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RELATED U.S. APPLICATION DATA
[0001] This application claims the benefit of priority of U.S. Provisional Application No. 61/277,555, filed on Sep. 28, 2009, and titled “Method and Means for Installing a Union Nut around a Valve Port”, incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] Service valve assemblies used to connect and control the flow of water through a tankless water heater are usually characterized by long valve bodies having numerous ports and at least 2 operable valves. A tankless water heater typically requires 2 service valves, a cold water service valve and a hot water service valve. The cold water service valve has a main valve for controlling the flow of cold water from a supply to the tankless water heater. The hot water service valve has a main valve for controlling the flow of hot water from the tankless water heater to one or more faucets. All service valve assemblies have a drain valve that allows the tankless water heater to be isolated from the supply and/or faucets such that service and maintenance operations can be performed on the tankless water heater. Drain ports open to the environment, so it is possible that someone opening a drain valve could be sprayed by water. If proper precautions are not taken, someone could accidentally open a hot water drain valve and be scalded.
[0003] Tankless water heaters are frequently installed into relatively small areas, so removing and replacing a bad service valve can be very difficult if there are long ports or protrusions off to the side of a valve assembly that prevent the valve assembly from rotating within a provided service area. To allow a valve assembly to be removable without needing to remove or damage an obstructing wall or structure, valve assemblies frequently are multi-piece assemblies. More piece parts usually means more opportunities for problems to develop between parts, and connectors always add bulk and length to an assembly. There is a need for a tankless water heater valve assembly that is safer to operate and easier to install.
SUMMARY OF THE INVENTION
[0004] The present invention is a service valve assembly that incorporates one or more safety features that also allow a valve body to be more compact, easier to install and of simplified operation. Tankless water heaters are typically located in tight spaces that can make access difficult. Because installed water pipes are usually not able to be rotated, installation of a valve assembly is facilitated if the valve assembly can be rotated within an axis area. By optimally foreshortening all perpendicularly protruding ports, potential for rotational freedom is maximized. In order to accomplish these goals, the main valve and the service valve are intentionally distinguished from each other as follows: a main valve is provided on a large port with a large valve handle that is able to be turned with ease, such as a lever handle, while a service valve is provided on a smaller port, with a relatively small valve handle that is intentionally difficult to turn without using a tool. Additionally, the main valve is intentionally oriented parallel to the water pipes such that a larger valve does not protrude in a limiting fashion as the valve is rotated during installation. Shorter perpendicularly protruding ports characterized by smaller valves contribute to easier installation, while distinct valve handles prevent confusion and/or accidental opening of a water valve, especially a hot water valve that could spray onto a person. Installation can further be simplified by using a unique union nut that allows a service valve to be easily connected to an existing tankless water heater.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 is a perspective view of a valve assembly of the present invention.
[0006] FIG. 2 is a cross sectional view through line 2 - 2 of FIG. 1 .
[0007] FIG. 3 is an exploded perspective view of the union in FIG. 1 .
[0008] FIG. 4 is a cross sectional view through line 4 - 4 of FIG. 3 .
[0009] FIG. 5 is a perspective view showing the union nut installed on the port.
[0010] FIG. 6 is a plan view of the union nut.
[0011] FIG. 7 is a perspective view showing the split ring installed on the port.
[0012] FIG. 8 is a plan view of the split ring.
[0013] The following is the list of numerical callouts used in FIGS. 1-8 :
10 . Valve assembly 12 . Casing 14 . First port 16 . Second port 18 . Main valve 20 . Main handle 22 . Third port 24 . Drain valve 26 . Drain handle 28 . Safety cap 30 . Fourth port 32 . Ridge 34 . Neck 36 . Flange 38 . Male Installation Threads 40 . First Seat 42 . Union Nut 44 . Shoulder 46 . Female Installation Threads 48 . Female Union Threads 50 . Split Ring 52 . Split 54 Inner cylindrical sleeve portion 56 . Outer cylindrical sleeve portion 58 . Middle cylindrical sleeve portion 60 . Rim 62 . Washer 64 . Adapter 66 . Second Seat 68 . Male Union Threads
DETAILED DESCRIPTION OF THE INVENTION
[0044] This detailed description will begin by describing the relevant components of a valve assembly that incorporates the present invention, followed by a description of safety and installation features, and then the various coupler components in the order that they are installed onto the valve assembly. Where reference numbers in one figure are the same as another figure, those reference numbers carry substantially the same meaning. Preferred sizes, materials and methods of attachment will be discussed, but these preferences are not intended to exclude other suitable or functionally equivalent sizes, materials or methods of attachment.
[0045] A valve assembly 10 has a casing 12 that encases at least two valves for selectively opening or obstructing the flow of water through pathways. The casing, which includes the entire valve body, is characterized by a main pathway for connecting a main inlet to a main outlet for the flow of water through the valve assembly. The main pathway is preferably the least restrictive path through and between the largest ports, or main ports, of the valve assembly. Other secondary ports frequently branch off of the main pathway at an angle, such as 90 degrees. All of these ports are part of the valve body. The casing can be formed from any known suitable material, such as metals or plastics, which meet the demands of a particular application. When used to service water pipes, the casing is preferably cast brass to allow the valve assembly to be compatible with numerous common pipe materials without creating an electric potential that causes corrosion.
[0046] A first port 14 , herein arbitrarily defined as a main port that is closest to the main valve of the valve assembly, is either an inlet or an outlet, depending on the desired direction of water flow. On a tankless water heater application, the first port of the cold water valve assembly is preferably an inlet connected to a water supply, while the first port of the hot water valve assembly is preferably an outlet connected to a faucet. The first port can terminate, at its open end, with a common connection means, such as male or female threads or a socket type connection.
[0047] A second port 16 is preferably a main port that is either an outlet or an inlet. The main valve 18 , which is intermediate the first port and the second port, is characterized by a valve member, such as a ball having a passageway that can be rotated, so a main valve whose valve member is a ball is a main ball valve. The valve member, which can open or obstruct the flow of a water through the valve body, is controlled by rotating a main handle 20 that turns a stem that passes through a bonnet in the casing and directly connects to the valve member. The main handle is preferably large enough to provide adequate leverage such that a user can rotate the main handle without requiring the use of any tools. A lever arm portion, such as a lever handle, or T-handle, is preferred. A lever handle's lever arm portion extends at least 2 cm from the stem portion of the main valve such that the main handle can be easily turned by hand without needing a tool. A T-handle's lever arm portion extends across the stem portion of the main valve, preferably spanning a distance of at least 3 cm, such that the handle can easily be grasped by a user's fingers. Obviously, larger main valves or difficult to turn stem portions will require a longer lever arm portion if it is desired to be able to operate a valve by hand.
[0048] A third port 22 , is incorporated into a valve body to provide access to a water system for service or maintenance by a user. On tankless water heater applications, the third port preferably protrudes perpendicularly from the main pathway through the valve body intermediate the main valve and the second port. To make installation of a valve assembly easier, especially in tight spaces, the third port should not protrude more than approximately twice the value of the outer diameter of the casing. The outer diameter of the casing should be determined by measuring around the casing at a cross-section that represents the surroundings of the chamber independent of any ports or other features of the casing. In order to accommodate a drain valve 24 that controls the flow through the third port, the third port is preferably smaller than the main ports to allow for the use of a smaller drain valve. Preferably, where ball valves are utilized in the valve assembly, the diameter of a main ball valve is at least 50% larger than the diameter of a drain ball valve. A smaller drain valve and third port that is perpendicularly protruding will not significantly contribute to the overall size of a valve assembly. This feature is particularly valuable to allow for the rotation of an entire valve assembly within an adjacent space, especially where existing water pipes are relatively fixed in location and orientation. An open end of the third port usually is characterized by male threads that can easily be connected to common hose connections, so the use of too large of a drain valve could cause the third port to perpendicularly protrude too far in a limiting manner.
[0049] The drain valve should only be open during servicing of the water system. A drain handle 26 of the drain valve preferably has a smaller profile that offers little leverage to a user, so it is very difficult to manipulate the drain valve's valve member without a tool, such as a wrench. A small hexagonal drain handle, which may also be slotted, is preferred. Most preferably, a thirteen millimeter, or half-inch, box-end, crescent or socket wrench can easily fit onto the drain handle for opening or closing the drain valve. Because a larger hexagonal drain handle is effectively a knob that can be turned by hand, it is recommended that no larger than about a fifteen millimeter hexagonal head be used. To provide an optional means for manipulating a drain, a slotted-head may be additionally incorporated into the drain handle such that a screwdriver or even a coin may be used to manipulate the drain valve orientation, especially because these tools are readily available.
[0050] Opening the drain valve can cause water to spray onto a user, especially an unintended user, who is unaware of the potential harm the water could cause to property or persons. Making the drain handle obviously different from the main handle, as described above, should help prevent someone from accidentally opening the drain port. A safety cap 28 is additionally used to protect the drain port from dirt that may damage valve components, from leaking and from being accidentally opened. Collectively, the smaller sized third port, drain valve and drain handle make for easier installations and safer access for servicing a system that utilizes the valve assembly. When a water system is equipped with more than one valve assembly, color coded valve handles will allow a user to quickly distinguish water flow and water characteristics, such as red for hot and blue for cold. Familiar ON/OFF arrows are also beneficial.
[0051] A fourth port 30 , optional, usually branching off of the main pathway somewhere between the main valve and the second port, can be provided to allow a pressure relief valve (not shown) to be installed onto the valve assembly. Pressure relief valves are usually not needed on a cold water valve because cold water supplies are expected to operate within a safe range of pressures. Additional or alternate ports, most commonly outlets, can be incorporated onto a valve body as needed. Because pressure relief valves can be relatively long, they protrude too far away from the valve assembly. In order to minimize this protrusion, the fourth port is preferably characterized by female threads. The fourth port can be larger in diameter than the diameter of the chamber, such that a female threaded portion of the fourth port is at least partially adjacent the chamber. Any suitable connection means can be formed or installed at an open end of any of the ports.
[0052] Most preferably, at least the second port of the above described valve assembly has a rotatable union nut installed over the port, without requiring the use of any tools. Brass, which is the preferred material for forming the valve casing, is cast, forged and/or machined to produce a desired shape. Unlike some other materials, it is not effective to try to flare or crimp the open end of a brass port to secure a union nut over the port such that the union nut rotates freely and can be threaded into a male fitting to be connected to the valve assembly. Instead, the following description explains how to make and install a rotatable union nut on a valve port.
[0053] A ridge 32 is formed around the exterior of the port such that a neck 34 is defined near the open end of the port. The neck is preferably machined, along with the other features described in this paragraph, such that a cast part that has not yet been machined probably is not characterized by any of these features. Adjacent the open end of the port is an outwardly flaring flange 36 , characterized by a larger diameter than at least the neck and ridge, formed to include male installation threads 38 . The male installation threads are preferably just a few projecting helical ribs having a fine pitch. It should be noted that the ridge and flange probably are not defined until after the neck has been machined into the port. The open end of the port terminates at a first seat 40 that has a flat and smooth face.
[0054] A union nut 42 is preferably made of brass, but it could also be copper, steel, iron or other metal that is compatible with a material being joined to, or it could be plastic, such as PVC. The union nut has an inwardly flaring shoulder 44 characterized by female installation threads 46 that are cut into the inner-most diameter of the shoulder. The diameter of the shoulder is too small to slip over the port on the valve body unless the female installation threads are screwed onto the male installation threads on the flange of the port. After several turns, the shoulder of the union nut is completely threaded over the flange of the port until the union nut freely slips past the neck and ridge on the port, no longer in threaded engagement. As is more common, the union nut is multi-sided, such as a hexagon, and characterized by female union threads 48 . The nominal diameter hole of the union nut is greater than the largest diameter of the shoulder, so the female union threads easily slide over the flange on the port.
[0055] After sliding the union nut over the port, a split ring 50 is installed around the neck of the port. The split ring is preferably a dielectric material, such as a strong plastic. The split ring is formed as two or three concentric offset cylindrical sleeves that do not have a continuous circumference because there is a split 52 that allows the split ring to be opened into a larger circumference. While the split ring is opened, it can pass over the flange on the port until it is positioned around the neck. Releasing the split ring will cause it to close around the neck such that an inner cylindrical sleeve portion 54 lies between the ridge and the flange of the port. An outer cylindrical sleeve portion 56 of the split ring partially covers the inner cylindrical sleeve portion, and fully covers the male installation threads on the port. A middle cylindrical sleeve portion 58 , if needed, joins the inner and outer cylindrical sleeve portions. With the split ring installed, the union nut can be partially drawn over the split ring until the shoulder of the union nut abuts an end of the outer cylindrical sleeve portion, against which the union nut can freely rotate. The shoulder is centered about the port by the inner cylindrical sleeve portion, which also serves to prevent the union nut from coming into electrical contact with the valve casing.
[0056] A washer 62 , most preferably made from rubber or other similar flexible material, is installed against the first seat 40 . The outer cylindrical sleeve portion of the split ring can extend beyond the end of the port such that a rim 60 can be used to centrally align the outer diameter of the washer. The inner diameter of the washer should be approximately the same size as the water pathway at the end of the port.
[0057] An adapter 64 , which is preferably made from a compatible or similar material as the union nut, is characterized by a second seat 66 that is positioned against the washer. The union nut can then be screwed to male union threads 68 on the adapter until the first and second seats are tightened against the washer. The other end of the adapter can be any desired connection means, such as a threaded connection or socket connection. Installation of a preferred service valve assembly can be performed by rotating the service valve to threadedly connect the first port to water pipes that are not able to be rotated, and then by using the above described union nut to connect the second port to the tankless water heater.
[0058] While a preferred form of the invention has been shown and described, it will be realized that alterations and modifications may be made thereto without departing from the scope of the following claims. | A service valve assembly for a tankless water heater incorporates one or more features that provide safer operation and easier installation of a valve assembly. Installation of a valve assembly is facilitated by foreshortening all perpendicularly protruding ports, thereby increasing the rotational freedom during installation. A main valve and a drain valve are intentionally distinguished from each other by providing different port sizes, valve handles and valve shapes that change the overall shape and characteristics of the valve assembly in such a way that accidental opening a drain port becomes much less likely. Installation can further be simplified by using a unique union nut that allows a service valve to be easily connected to an existing tankless water heater. | 18,979 |
FIELD OF THE INVENTION
The invention relates to a method for damping the kinetic energy of ions in ion cells filled with collision gas and with an exit aperture to drain the ions out of the cell.
BACKGROUND OF THE INVENTION
Some types of mass spectrometers, for example time-of-flight mass spectrometers with orthogonal ion injection, require a very well-conditioned ion beam for high mass resolution and precise mass determination. By a “well-conditioned ion beam” we mean here a beam of ions flying as parallel as possible with kinetic energies which are as uniform as possible. This “ion beam conditioning” can consist in first decelerating the motion of the ions in a conditioning cell by numerous collisions with a collision gas, drawing the decelerated ions out of the conditioning cell through suitable diaphragm systems, and then forming them into a relatively fine, almost parallel ion beam. The process of reducing the kinetic energy of the ions by decelerating them in a collision gas is termed “thermalization”. This reduces the “phase volume” of the ions. By “phase space” we mean the six-dimensional space made up of space and momentum coordinates measured in an entrained system of coordinates; by “phase volume” we mean that part of the phase space which is filled with ions. Good beam conditioning always requires compression of the phase volume.
For a time-of-flight mass spectrometer with orthogonal ion injection, high mass resolution requires that a fine ion beam as parallel as possible with a diameter of only 0.5 millimeters if possible be generated, whereby the energy of the ions in the beam should be as uniform as possible, for example 20 electron volts with deviations of less than 0.5 electron volts. Ions from normal ion feeding systems, for example RF ion guidance systems, have a much larger phase volume and therefore have to be conditioned before being fed into a mass spectrometer of this type.
Conditioning the ions by reducing their phase volume like this cannot be achieved by ion-optical methods (a consequence of the Liouville theorem) and with the exception of the complicated method of laser cooling, only the gas cooling described can reduce the phase volume. U.S. Pat. No. 4,963,736 (D. J. Douglas and J. B. French) describes an RF-operated ion guidance system which conditions the ions by cooling them for optimum injection into a mass-selective quadrupole filter.
Ion storage cells filled with collision gas have proved successful in reducing the phase space, whereby the cells consist, for example, of four round rods positioned between the diaphragm systems on the input side and output side, and which use a supply with both phases of an RF voltage to build up an essentially quadrupole alternating field which, in conjunction with retaining potentials on the diaphragm systems, retains the ions in the storage cell.
The demands on the conditioning cells are particularly high if it is intended that the conditioning cells will also be used for the fragmentation of ions, i.e. when it is intended that the deceleration gas will be simultaneously also used as the collision gas for a fragmentation. For fragmentation, the ions are injected into the collision-gas filled system with kinetic energies of between 30 and 200 electron volts. The fragmentation process is denoted by the abbreviation CID (collisionally induced decomposition); the fragmentation occurs only after many collisions, when the ion has absorbed sufficient intrinsic energy as a result of the high proportion of collisions to lead to the fragmentation of a bond. Regardless of whether the ions are fragmented or not, they are also kinetically cooled in the collision gas simultaneously and in competition with the fragmentation, i.e. their kinetic energy decreases. The fragmentation process in these quadrupole systems would proceed more effectively in collision gases with a heavier molecular weight; these heavier gases cannot be used, however, since their gas molecules deflect the ions more strongly to the side during collisions and it is then very easy for the ions, as a result of such collision cascades, to escape laterally out of the round-rod quadrupole system.
All current tandem mass spectrometers require collision cells for the fragmentation of one species of ion (the “parent ions”) in order to obtain information about the structure of the parent ions by analyzing the fragment ion spectrum (or “daughter ion spectrum”). In general, the parent ions are selected from a primary ion mixture by a quadrupole filter; then fragmented in the collision cell; after fragmentation, the daughter ions can be analyzed in quadrupole mass spectrometers, time-of-flight mass spectrometers with orthogonal ion injection, in RF ion traps or in ion cyclotron resonance spectrometers.
For many years, RF quadrupole systems have been used as collision cells, which are usually constructed of round rods and operated with purely RF voltage without superimposed DC voltage (in the so-called “RF-only mode”), usually with helium as the collision gas (sometimes with nitrogen), and in which both the parent and also the daughter ions remain trapped as well as possible. Mass spectrometers which use quadrupole filters near the inputs and near the outputs to select or analyze ions have become known as “Triple-Quads”, for obvious reasons; these Triple-Quads have been known for around 15 years.
Collision cells usually consist of RF rod systems with round rods, although for high-quality quadrupole mass spectrometers, hyperbole systems, which permit significantly better separation efficiency and transmissions, have established themselves in the last 30 years. Inexpensive round-rod systems are still considered good enough for the collision chambers, expensive hyperbole systems are not used at all.
From the work of F. von Busch and W. Paul, Z. Phys. 164,588 (1961), however, it is already known that in round-rod quadrupole filters, non-linear resonances exist which lead to the ejection of those ions whose motion parameters lie in the middle of the “Mathieu stability zone” and which should therefore be collected in a stable state. In three-dimensional RF ion traps, these resonances lead to the phenomenon of “black holes”, which occur in the same way in rod systems, particularly in round-rod systems. Round-rod systems contain octopole and higher even-numbered multipole fields of considerable strength superimposed on the quadrupole field, leading to a distortion of the ion oscillations in the radial direction and hence to the formation of overtones of the ion oscillation. Their meeting with the Mathieu side bands leads to the resonances, which only occur, however, when the ions sweep through relatively wide radial oscillations. For ions lying damped in the axis of the system, the resonances are not effective. The Mathieu stability field is traversed by numerous non-linear resonance lines, the resonances are by no means rare.
Now it is precisely the case in collision cells that the ions injected with higher energies of between 30 and 200 electron volts must reach the vicinity of the rods or their intermediate areas in large numbers by means of collision cascades, and they are therefore inevitably subjected to the phenomenon of non-linear resonances if they fulfill the resonance conditions. Specific species of daughter ions can thus disappear from the collision cell and hence out of the daughter ion spectrum and thus adulterate the spectrum of the daughter ions. In the most unfavorable case, even the selected parent ions are subjected to this resonance and disappear to a large extent from the collision cell.
Apart from this, round-rod systems have the further disadvantage that the pseudopotential wall between the rods is extremely low (for commercially available systems only some ten to twenty volts) and can easily be overcome by ions with an energy of 50 electron volts, usually the minimum energy required for fragmentation processes, by means of a random laterally-deflecting collision cascade. This escape affects both parent and daughter ions. The higher the mass of the collision gas molecules, the more ions are lost, because in this case, the angles of deflection per collision are greater. A cascade of a few collisions which coincidentally deflect in the same lateral direction is enough to remove the ion from the collision cell. In the case of a very light collision gas, the larger angles of deflection of a small number of collisions are no longer able to compensate statistically as well as the large number of smaller angles of deflection.
As far as the conditioning of the ions is concerned, a disadvantage of most collision cells is that either the ions leave the cell again with relatively high energy after sweeping through once, since their energy has not been sufficiently reduced by collisions, or that, after a sufficiently large number of collisions (after a long sweep at high pressure or also after several sweeps with reflections at the ion output) they have given up their kinetic energy apart from residues of thermal energy and then remain in the collision cell. There has been a long search for collision cells which make it possible to construct an axial DC voltage drop to fish out the fragmented and thermalized ions from the collision cell in an efficient and uniform manner. The DC voltage drop needs only to be a few volts.
The easiest way to generate a DC voltage drop is in a quadrupole electrode system made of four thin resistance wires. The thin wires require an extremely high RF voltage, however, in order to build up the quadrupole RF field since the largest voltage drop occurs in the immediate vicinity of the thin wire. In addition, the resistance must not be particularly high, otherwise the RF alternating voltage cannot propagate along the wires sufficiently quickly. It is therefore only possible to generate very low DC voltage drops along the wire. Moreover, the pseudopotential wall between the wires is very low; the ions can escape very easily. Furthermore, the proportion of higher multipole fields is very high. Hyberbolic quadrupole systems comprising a large number of clamped parallel wires which imitate the four hyperbolic areas of the ideal quadrupole system provide a way out. Quadrupole systems replicated in wire like this were already being used around 40 years ago in the laboratories of Wolfgang Paul, the inventor of all quadrupole systems. These quadrupole systems are difficult to produce, however, and not very precise.
Another type of ion storage system with an electrically switched forward thrust is known from patent specification U.S. Pat. No. 5,572,035 (J. Franzen). The patent specification relates to various types of ion guidance systems which are completely different to the rod and wire systems described here. One of these consists of only two helical, coiled conductors in the shape of the double helix, operated by connection to the two phases of RF voltage. Another consists of coaxial rings connected in turn to the phases of RF alternating voltage. Both systems can be operated so that an axial forward thrust of the ions is generated. The double helix can be produced from resistance wire across which a DC voltage drop is generated, in a similar way to the quadrupole rod system made of thin wires; since the double helix is more compatible with thinner wires, however, and also has longer wires, it is more suitable for the DC voltage drop. The individual rings of the ring system can be supplied with a DC voltage potential which decreases in stages ring by ring, as also described in the patent.
Further solutions for collision cells which permit a thrust of the ions along the axis in the interior of the system are described in U.S. Pat. No. 5,847,386 (B. A. Thomson and C. L. Jolliffe) and protected by patent. All these systems are based on round rods:
(a) a segmented quadrupole system made of a chain of a few short rod systems whose potential on the axis falls off in stages; (b) a quadrupole rod system made of conically tapering rods running parallel to the axis; (c) a quadrupole rod system whose rods are arranged conically against each other; (d) a quadrupole system of parallel rods with externally encompassing rings at DC voltage potentials which decrease step by step and which reach into the interior of the rod system
where they generate a decreasing potential on the axis;
(e) a quadrupole rod system whose nonconducting rods have an externally applied resistance layer across which a voltage drop is generated (better than the quadrupole system made of thin resistance wires); (f) a quadrupole rod system made of insulating thin-walled ceramic tubes, with an external resistance layer for a DC voltage drop and an internal metal layer for the RF feed which acts through the insulator to the outside; (g) a quadrupole rod system with auxiliary electrodes at weak DC voltage potential between the rods, whereby the auxiliary electrodes are arranged so as to taper to the axis of the system. The auxiliary electrodes are each located at the point of the zero potential of the two-phase RF voltage which is applied alternately across the rods. This generates a potential on the axis with potential gradient along the axis.
These arrays are, however, not completely satisfactory: partly because they are complicated to produce and therefore not particularly cheap, and partly because they function only moderately satisfactorily. The transitions between the split quadrupole systems thus present transmission losses and reflections in System (a). System (g) with the long auxiliary diaphragms between the rods exhibits larger ion losses in practice as a result of touching the auxiliary electrodes, which fundamentally decrease the height of the pseudopotential wall between the rods. This system has only limited suitability for the fragmentation of ions since the fragmentation always scatters the ions as well, and the losses are therefore much too high. The nonconducting rods (e) with resistance coating only partially conduct the RF voltage since here the higher capacity of the system compared with the thin wires means larger currents must be carried; or conversely, the resistance coating must really have an extremely low resistance. The ion guidance system (c), which is tapered instead of cylindrical, drives practically only those ions forward which have not collected at rest in the axis of the system, since only these experience a potential with a forward thrust. Almost the same is true for the rod system (b) comprising tapering rods. System (f) comprising thin ceramic tubes (according to the description tube walls around 0.5 to 1 millimeter thick) with interior metal coating to generate the RF field, and exterior resistance layer for the DC voltage drop, has disadvantages: the RF frequency causes such high dielectric losses in the material of the ceramic tubes that the system becomes extremely hot within a very short time and practically glows in the vacuum.
DE 102 21 468 A1 (J. Franzen and A. Brekenfeld) presents further systems with axial DC voltage drop, which are essentially based on the effect of DC voltages on externally encompassing tapering or trumpet-shaped electrodes.
It should be mentioned also that all rod systems into which external DC voltage potentials reach, as in U.S. Pat. No. 5,847,386, case (d) or (g), or as in DE 102 21 468 A1, are disadvantageous. The DC potential on the axis of the rod system is raised, thereby disturbing the parabolic minimum of the pseudopotential in the axis. In a quadrupole system of this type, four new potential minima in which the ions can oscillate are created between the axis and the rods. The possible oscillation amplitudes for the ions are extremely limited, however; the ions can easily collide with the rods and be lost through discharge.
The best systems are those which leave the parabolic minimum in the axis of the rod system undisturbed yet generate a DC voltage drop, as is the case with the rod system made of thin resistance wires or case (g) from U.S. Pat. No. 5,847,386, whose basic principle of the dielectric penetrated by RF has also been known for a long time. Every conductor radiates RF, whether it is insulated or not. A cylinder made of resistance material penetrated by RF has also been known as a “leaky dielectric” for some time (P. H. Dawson, “Performance of the Quadrupole Mass Filter with Separated RF and DC Fringing Fields”, Int. J. Mass Spectrom. Ion Phys., 25 (1977) 375-392. Cited is: W. L. Fite, Rev. Sci. Instrum., 47 (1976) 326).
Multipole systems of a higher order can also be used as a collision cell. Such multipole systems comprise more than just two rod pairs. With more than two rod pairs, hexapole, octopole, decapole, dodecapole fields etc. are created. Both phases of a two-phase RF voltage are applied across two neighboring rods. Walls of a so-called pseudopotential then develop between the rods, as is the case with the quadrupole system, these walls hold the ions in the interior of the rod system. In contrast to the quadrupole system, the pseudopotential forms a flat trough in the vicinity of the axis in which the thermalized ions collect further away from the axis than is the case with the parabolic minimum of a quadrupole system. The more rod pairs there are, the shallower the trough. Multipole systems are therefore not as suitable as quadrupole systems for beam conditioning. In octopole systems, it is even possible to observe that the Coulombic repulsion of the ions causes them to collect around the fringes; the axis has a much lower ion density. For some types of mass spectrometer, the higher multipole systems cannot therefore be used as a collision cell for the analysis of the daughter ions owing to their poor beam conditioning.
Time-of-flight mass spectrometers with orthogonal injection of a primary ion beam possess a so-called pulser at the beginning of the flight path which accelerates a section of the primary ion beam, i.e. a string-shaped ion package, at right angles to the previous direction of the beam. This forms a ribbon-shaped secondary ion beam in which light ions fly quickly and heavier ones more slowly, and whose direction of flight lies between the previous direction of the primary ion beam and the direction of acceleration at right angles to this. A time-of-flight mass spectrometer of this type is preferably operated with a velocity-focusing reflector which reflects the whole width of the ribbon-shaped secondary ion beam and directs it towards a similarly extended detector.
If all ions fly in a line exactly in the axis of the pulser, and if the ions have no velocity components transverse to the primary ion beam, then theoretically—as can easily be understood—an infinitely high mass resolution power can be achieved, since all ions with the same mass fly precisely in the same front and reach the detector at precisely the same time. If the primary ion beam has a finite cross section, but no ion has a velocity component transverse to the direction of the beam, then spatial focusing of the pulser again theoretically means an infinitely high mass resolution can be achieved. The high mass resolution can even still be achieved if a strict correlation exists between the ion location (measured from the beam axis of the primary beam in the direction of the acceleration) and the ion transverse velocity in the primary beam in the direction of the acceleration. If no such correlation exists, however, i.e. if ion locations and ion transverse velocities are statistically distributed with no correlation between the two distributions, then it is no longer possible to achieve high mass resolution.
The primary ion beam must therefore be conditioned with respect to location and velocity distribution in order to achieve a high mass resolution in the time-of-flight mass spectrometer.
Beam conditioning is also required for other types of mass spectrometer, or at the very least it is useful. Every mass spectrometer has a phase space acceptance cross section which determines which of the injected ions are accepted and which deflected or reflected.
SUMMARY OF THE INVENTION
The invention uses a conditioning cell with an adjustable DC potential which decreases towards the exit aperture to compress the phase volume of the ions by damping their kinetic energies, collecting the ions after thermalization in the spatial potential minimum thus created and letting them drain away relatively slowly through a central potential minimum in the exit aperture system. This facilitates the production of very fine, highly parallel ion beams which consist of almost monoenergetic ions. In particular, the method can also be coupled with a fragmentation of the ions.
The invention provides a method in which a fine monoenergetic ion beam is produced by steps including:
(a) injecting ions into a conditioning cell filled with a collision gas thereby thermalizing the ions, the collision cell having a diaphragm system to drain the ions out of the conditioning cell; (b) collecting the ions in a DC potential well in front of the diaphragm system; and (c) draining the ions out of the conditioning cell via a fine overflow potential minimum in the diaphragm system.
This generates the desired fine beam with ions displaying high energy homogeneity. Here, the potential minimum in the diaphragm system, viewed in the plane of the apertured diaphragms, is a point-shaped potential minimum directly at the center of the apertured diaphragms, with the potential increasing radially very quickly to a high barrier potential. A wall with a narrow channel forms along the axis of the electrode system and acts as the overflow.
On the one hand, the method can run continuously by having simultaneous and continuous ion introduction, thermalization, collection and draining over a pre-determined time interval. On the other, it can be also be discontinuous, in which case introduction, thermalization and collection form the first phase of the method, and the draining forms a second phase, whereby during the draining, the voltage drop along the conditioning cell can be temporally changed to make it possible for the draining to continue until the potential well is empty. This process can be repeated a number of times.
The method can use a conditioning cell constructed of parallel ring electrodes. The generation of a potential gradient in such a cell is known from patent specification U.S. Pat. No. 5,572,035. It is also possible, however, to use a conditioning cell consisting of two or more helical, coiled wires. In this case also, the generation of a potential gradient is known from the patent specification cited.
Lastly, it is possible to use a conditioning cell consisting of longitudinal electrodes in which a multipole RF field is present.
The conditioning cell uses in particular four longitudinal electrodes which generate a quadrupole field, because this quadrupole field possesses a well-formed pseudopotential minimum. The generation of DC voltage potential gradients in such quadrupole systems is described below. To avoid ion losses, the quadrupole RF field can be generated so as to be as free as possible from superimpositions with higher multipole fields by designing the longitudinal electrodes which generate the RF field with a hyperbolic shape towards the interior.
A DC voltage potential gradient can be generated by longitudinal electrodes equipped with electrically conductive surface layers and each separated from the RF-carrying longitudinal electrode below by a thin insulating layer and supplied with a mixture of RF and DC voltages. The potential gradient is generated via a DC voltage drop across the electrically conductive surface layers. This keeps the pseudopotential minimum in the axis. When plotted over a cross-sectional area of the quadrupole system, this minimum has the shape of a rotary paraboloid. Thermalized ions collect exactly in the axis of the quadrupole system.
It may be desirable to select at least two individually adjustable potential gradients along the quadrupole system; this can be achieved by them each having at least one through-hole plating of the surface layers to the longitudinal electrode below. If the longitudinal electrodes are hyperbolic in shape, the insulated surface layer only needs to cover the hyperbolic part of the longitudinal electrode.
For the task of collisionally induced fragmentation, it is particularly favorable to use hyperbolic electrodes since, here, the risk of losses due to collision cascades and nonlinear resonating daughter ions is particularly high. Before being put into operation, the collision cell is filled, as usual, with a collision gas at a pressure of between 10 −2 and 10 +2 Pascal, the ions to be fragmented are injected from one of the ends with energies of between 30 and 200 electron volts.
A hyperbolic quadrupole system has the advantage over the round-rod systems regularly used nowadays in that, firstly, there is no escape via nonlinear resonances and, secondly, the pseudopotentials arising from the axis in all radial directions have the same slope, i.e., supply the same restoring forces. The escape of ions via too low a pseudopotential wall between the pole rods as a result of laterally deflected collision cascades is almost completely prevented; if ions at all get lost from this system it is by the rare cases of colliding with the electrodes.
The mixture of RF and DC voltages for the DC voltage drop along the system can be generated using an air core transformer whose secondary windings are each designed to take both phases at least twice so that the DC voltage potentials can be fed into the cold center taps of two secondary windings. Three secondary windings are favorable: one winding serves to supply the RF for the hyperbolic electrodes, and two windings serve to supply the superimposed DC voltage. This enables two independent potential gradients to be generated.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows the scheme of a collision and conditioning cell according to the invention in a tandem mass spectrometer. The ion beam ( 50 ) is injected through the diaphragm system ( 51 ) into a quadrupole system ( 52 ) to select the parent ions; the parent ions selected are accelerated through the diaphragm system ( 53 ) and injected into the quadrupole system ( 54 ) forming the collision cell where they are fragmented; finally, thermalized fragment ions and the remaining parent ions are threaded through the potential overflow in the diaphragm system ( 55 ) into the pulser ( 56 ) of a time-of-flight mass spectrometer where they are accelerated, locally focused, through the accelerating electrodes ( 57 ) as an ion beam ( 58 ) into the flight path.
FIG. 2 shows a three-dimensional diagram of the potential well with exit channel at the end of the collision cell, shown as a longitudinal section of the collision cell. The parabolic potential minima of the quadrupole system decrease towards the exit end and are terminated by the potential distribution of the apertured diaphragm system. An ion pool is formed in the potential well with a surface ( 48 ) whose ions can drain away through the narrow exit potential channel ( 49 ) in the apertured diaphragm system.
FIG. 3 represents a glass quadrupole system which can form the essential part of a conditioning cell. The apertured diaphragm systems on both sides are not shown. The hyperbolic electrode sheets ( 2 , 3 ) are melted onto the inside of the glass body ( 1 ), and the insulated resistance layers are vapor deposited onto these. The connector pins ( 4 , 5 , 6 , 7 and 12 , 13 , 14 ) bring the DC voltage to the resistance layers, the connector pins ( 8 , 9 , 10 ) guide the RF voltage to the electrode sheets.
FIG. 4 illustrates a quadrupole system made of rigid aluminum electrodes ( 21 , 22 , 23 , 24 ), on whose anodized oxide layer the resistance layers ( 25 , 26 , 27 , 28 ) are applied, screwed into a glass holder ( 20 ) with a precise internal cross section.
FIG. 5 depicts an example of a diagram of the voltage supply with mixing of the RF phases and the DC voltage potentials; a transformer with three secondary windings is used to generate two potential gradients.
FIG. 6 is a schematic diagram of a quadrupole system (row A) with longitudinal electrodes ( 70 ) and resistance layer ( 71 ) with through-hole plating ( 72 ) and underneath the filling (row B) and emptying of the ion pool (rows C to E) by changing the DC potentials in the quadrupole system and across the exit diaphragm system ( 74 ).
DETAILED DESCRIPTION
A preferred embodiment of the method for producing a fine ion beam with ions displaying homogeneous energies consists in using a hyperbolic quadrupole system which facilitates the generation of an axial potential gradient, roughly the quadrupole system ( 54 ) in FIG. 1 , in conjunction with a diaphragm system ( 55 ) at the ejection end of the quadrupole system. The ions can be introduced through an injection diaphragm system ( 53 ) into the interior of the quadrupole system, for example. A glass quadrupole system ( 1 ) shown in FIG. 3 can be used as the quadrupole system, for instance. For this, the quadrupole system is filled with collision gas at a pressure of between 10 −2 and 10 +2 Pascal, causing the ions to thermalize more or less rapidly, i.e. they give up their kinetic energy to the collision gas keeping only thermal residual energies. The restoring forces of the pseudopotential cause the ions having lost their kinetic energy, to collect in the axis of the quadrupole system.
By switching on a weak DC voltage drop across the electrically conductive surface layer of the quadrupole system ( 1 ), the ions are driven slowly in the axis to the exit end of the quadrupole system. By applying DC voltages across the diaphragm system ( 55 ) ( FIG. 1 ) on the exit side in this case, a potential barrier can be set up so that here in the end of the quadrupole system an “ion pool” forms within the potential well which slowly fills with ions, whereby the ions in the ion pool are continuously further thermalized in the collision gas. The potential well of the “ion pool” with the ion reflector ( 48 ) is shown in FIG. 2 as a potential over a section of the longitudinal axis. The apertured diaphragm system ( 55 ) ( FIG. 1 ) barring the ions now possesses a potential minimum directly in the axis, which forms a point-shaped overflow ( 49 ) ( FIG. 2 ) over which the ions from the ion pool can slowly drain away out of the quadrupole system. A restoring potential of this type with a point-shaped overflow in the axis can easily be produced by the three apertured diaphragms ( 55 ) ( FIG. 1 ) supplied with a DC voltage. The ions which drain out of the ion pool like this are very monoenergetic; it is thus possible, as mathematical simulations demonstrate, to generate ion beams which have an energy spread of only 0.2 electron volt.
The “ion pool” in FIG. 2 is here a symbolic representation. The filling of the pool and the associated spatial expansion of the ions is a result of the Coulombic repulsion of the ions. The surface ( 48 ) does not exist, of course, since the ions collect in a three-dimensional lobe with rotational symmetry. The surface ( 48 ) here actually indicates a particular pressure of the Coulomb potential which presses the ions against the pseudopotential of the quadrupole system and against the barrier potential of the diaphragm system. If the collection of ions is large enough to make this Coulomb pressure sufficiently high, the ions can drain away via the overflow potential of the diaphragm system. This effect produces the extraordinarily good energy homogeneity of the ions draining away.
If the ions are injected through the injection diaphragms ( 53 ) with sufficient energy, most of them are fragmented. The conditioning cell then acts as a collision cell for the fragmentation of the ions (CID=collisionally induced decomposition).
This embodiment of a collision cell can be used for an arrangement which, according to FIG. 1 , comprises a selective quadrupole filter mass spectrometer ( 52 ), the quadrupole system ( 54 ) forming the collision cell, a pulser ( 56 ) for the ion beam in the time-of-flight mass spectrometer and the apertured diaphragm systems ( 51 ), ( 53 ) and ( 55 ).
A preferred embodiment of the quadrupole system for the collision cell assumes, as shown in FIG. 3 , a normal monolithic glass quadrupole ( 1 ) with melted-on hyperbolic sheet surfaces ( 2 , 3 ), as described in DE 27 37 903 (U.S. Pat. No. 4,213,557). The glass quadrupole system is formed in one operation in a hot molding process and fused with the sheet electrodes ( 2 , 3 ) and is thus relatively inexpensive to manufacture. It is extraordinarily precise in maintaining all dimensions.
The hyperbolic surfaces ( 2 , 3 ) of a glass quadrupole of this type are thinly coated with insulating paint and after drying in the vacuum, a thin layer of chromium is vapor deposited which acts as the electrically conductive surface layer. The chromium layer deposited in this process is only a few nanometers thick, it is possible in this case to generate a resistance of around five kilohms with good reproducibility. The chromium layer extends here to the end surfaces and also covers the front area of the glass so that connector pins ( 4 , 5 , 6 , 7 , 12 , 13 , 14 ) can be connected with the chromium layer on the electrodes ( 2 , 3 ) via a conductive paint. For a voltage drop of five volts, a current of one milliampere flows with a loss of power of five milliwatts. A voltage drop of five volts is more than sufficient; a smaller voltage drop is usually used.
Instead of the chromium layer it is also possible to apply a layer of another metal. At a defined position, the chromium layer can be connected to the hyperbolic electrode underneath by means of a gap in the insulating layer as schematically represented in the supply diagram in FIG. 5 . It is then possible to produce sections with different voltage drops.
A favorable embodiment for the voltage supply is illustrated schematically in FIG. 5 . A transformer is used for the voltage supply which uses a primary winding ( 30 ) and three secondary windings ( 34 , 37 ), ( 32 , 35 ) and ( 33 , 36 ), each with a center tap. The secondary windings are (unlike the schematic drawing which makes use of the form usually used in electrical engineering) all wound on the same core with the same coupling to the primary winding ( 30 ). This can be an air core transformer or a transformer with magnetic core, for example with ferrite core. The hot ends of the secondary winding ( 33 , 36 ) supply the four hyberbolic electrode sheets in the usual way, electrodes ( 40 , 41 ) positioned opposite each other each being supplied with the same phase (the two other electrodes and their supply are not shown here).
Two independently variable DC voltages ( 38 ) and ( 39 ) are fed into the center taps of the two other secondary windings ( 34 , 37 ) and ( 32 , 35 ) and the aforementioned secondary winding ( 33 , 36 ). The ends ( 32 ) and ( 34 ) of these windings are each connected with the ends of the insulated chromium layers ( 42 , 43 ) applied to the electrodes ( 40 , 41 ) in such a way that a DC current flows through the windings and the chromium layer, generating a voltage drop while, at the same time, the RF alternating voltage is also applied across both ends. The resistance layers ( 42 , 43 ) are connected with the hyperbolic electrodes below at position ( 44 ), it is therefore possible to generate two independent voltage drops in the sections ( 45 , 44 ) and ( 44 , 46 ) of the quadrupole system.
The RF alternating voltage of these feeds does not have to supply all the chromium layers ( 42 , 43 ) with RF voltage in this case, since there is capacitive coupling between the RF voltage through the insulating paint and the hyperbolic electrodes ( 40 , 41 ), which are good conductors. This simple circuit avoids the use of capacitors, resistances or inductors to connect the hot side of the transformer windings. It is possible to use a litz wire made of three braided strands for the windings, for example.
Since the electrically conductive surface layers ( 42 ) and ( 43 ), which each form a resistance layer insulated from the hyperbolic electrodes ( 40 ) and ( 41 ), are connected at position ( 44 ) with the hyperbolic electrodes ( 40 ) and ( 41 ) below, it is possible to form the voltage drop in the two partial sections ( 45 , 44 ) and ( 44 , 46 ) separately. The two independently adjustable potential gradients can be used to greatly vary the size of the pool which results in the overflow. A very small voltage drop in the larger part of the quadrupole system and a slightly higher potential gradient in front of the ejection diaphragm system make it possible to produce a small pool.
The two independent voltage drops in the sections ( 45 , 44 ) and ( 44 , 46 ) make it possible to empty the ion pool more rapidly at the end of a measurement by using a continuous increase of the voltage drop ( 44 , 46 ) to reduce the expansion of the pool and by completely draining the pool via the potential channel in the apertured diaphragm system on the output side.
The glass quadrupole system of FIG. 3 is eminently suitable for filling with collision gas. Clean nitrogen can be used for this, it is not necessary to use expensive helium in this case since, even with collision gases of higher molecular weights, the collision cascades with random lateral deflection do not lead to noticeable ion losses. Nitrogen as the collision gas has a higher fragmentation yield. It is even possible to use argon as the collision gas, producing an even higher fragmentation yield. It is advisable to make the injection and ejection apertures as fine as possible in order to be able to keep the pressure in the collision cell high without worsening the vacuum in the surrounding mass spectrometers by providing them with more collision gas than they can tolerate. A higher pressure leads to more rapid fragmentation and thermalization, which is particularly favorable for pulsed operation.
Gas mixtures, for example helium and argon, can create an equilibrium between thermalization and fragmentation. In this case, the helium is mainly responsible for the thermalization, the argon for the fragmentation. The mixture enables the desired ratio of fragmentation to kinetic cooling to be produced.
As illustrated in FIG. 1 , the hyberbolic quadrupole system ( 54 ) is sealed on both sides with apertured diaphragm systems ( 53 ) and ( 55 ). The apertured diaphragm system on the input side ( 53 ) provides the accelerating voltage for the subsequent fragmentation, the apertured diaphragm system on the output side ( 55 ) provides only a fine potential minimum in the axis to drain away thermalized ions, otherwise it is ion repulsive. The parent ions are selected in the quadrupole system ( 52 ). The usual method here is to select the whole isotope group of the parent ions in order to recover the isotope groups in the daughter ion spectrum; the specific mass range selected is therefore roughly between three and five mass units per elementary charge. The parent ions which are injected with energies of between 30 and 200 electron volts will first traverse the collision cell ( 54 ) with a few hundred collisions and be reflected on the output side of the diaphragm system ( 55 ). On returning to the diaphragm system on the input side ( 53 ) they are reflected again; they thus oscillate in the hyperbolic quadrupole system ( 54 ) until they are thermalized. This causes a proportion of the ions to be fragmented, this proportion depending on the collision density and the power of the collision. The collision density is given by the number, the power of the collision by the mass of the collision gas molecules. The thermalized ions collect in the axis of the quadrupole system, in the minimum of the pseudopotential.
The slight DC voltage drop along the quadrupole system ( 54 ) allows the thermalized ions to flow towards the output in front of the diaphragm system ( 55 ), where they collect in the “ion pool”. According to the invention, the potential of the outflow aperture in the axis of the diaphragm system ( 55 ) is kept high enough so that a certain quantity of thermalized ions must first fill the ion pool with a certain “overflow pressure” before the ions can emerge over the slight potential threshold in the outlet hole. As described above, the overflow pressure is formed by the Coulombic repulsion of the ions in the ion pool. This overflow out of an ion pool provides ions with extraordinarily homogeneous energies (“monoenergetic” ions).
It is possible to form an ion beam out of the outflowing monoenergetic ions which is eminently suitable for a time-of-flight mass spectrometer with orthogonal injection. The non-thermalized ions which occasionally emerge from the fine aperture, ions which can only emerge when they, by a rare coincidence, aim directly at this potential hole, are not a problem in the subsequent time-of-flight mass spectrometer because their velocity is too high and they either quickly completely sweep through the pulser or, alternately, they cannot hit the ion detector at the end of the flight path after being ejected as a pulse in the pulser. If the ions are injected into the collision cell with a small angle, their chance of escaping unthermalized from the overflow potential channel is reduced. Injection at a small angle is the norm for ions coming out of a selective quadrupole system, since the radial oscillation of the ions in the selective quadrupole occurs to a large extent unhindered.
The quantity of ions in the ion pool, which brings about the draining, depends on the profile of the DC voltage along the quadrupole system. As described above, this profile can be generated by three or more windings of the RF transformer. Controlling the voltage drop in front of the apertured diaphragm system on the output side makes it possible to empty the pool after measuring a daughter ion spectrum slowly and completely.
The quadrupole system with hyperbolic electrodes can be constructed in a completely different way, as shown in FIG. 4 . For example, four electrodes ( 21 , 22 , 23 , 24 ) can be manufactured out of aluminum with a hyperbolic electrode surface on the front and shaped on the rear so that there is a good screw fit in a retaining insulator ( 20 ). The retaining insulator ( 20 ) can be produced out of glass, for instance, using a method for producing so called “calibrated precision glass”, for example. The aluminum electrodes ( 21 , 22 , 23 , 24 ) are strongly anodized on the hyperbolic side at least, thus forming a nonconducting oxide layer. A thin layer of metal is then, in turn, vapor deposited onto this layer in order to produce the resistance layers ( 25 , 26 , 27 , 28 ) on the surface. The vapor is again deposited only on the hyperbolic surface here. The screw-fastened system is bonded in a similar way to the quadrupole system made of hyperbolic sheets which are melted onto the glass.
The collision cells according to the invention are particularly suitable for operation with a quadrupole mass spectrometer for selecting the parent ions, and with a time-of-flight mass spectrometer with orthogonal ion injection for analyzing daughter ions, as shown in FIG. 1 . The time-of-flight mass spectrometers provide extraordinarily good accuracy for mass determination; even with relatively small table-top instruments it is possible to obtain mass determinations to an accuracy of two to three millionths of the mass in a mass range of around 200 to 4000 atomic mass units, i.e. eminently suitable for the exceedingly interesting use in the field of protein and peptide analysis. This method is especially good for de-novo sequencing of peptides, i.e. the determination of the sequence of amino acids with no additional prior knowledge.
Time-of-flight mass spectrometers with orthogonal injection of a primary ion beam have a pulser ( 56 ) at the beginning of their flight path which accelerates a section of the primary ion beam, i.e., a fine string-shaped ion package, at right angles to the previous direction of the beam. This forms a ribbon-shaped secondary ion beam ( 58 ) in which light ions fly quickly and heavier ones more slowly, and whose direction of flight lies between the previous direction of the primary ion beam and the direction of acceleration at right angles to this. A time-of-flight mass spectrometer of this type is usually operated with a velocity-focusing reflector which reflects the whole width of the ribbon-shaped secondary ion beam and deflects it onto a detector which is also extended.
The resolution of this time-of-flight mass spectrometer depends on the quality of the primary ion beam, as described in the introduction. The primary ion beam must therefore be conditioned with respect to spatial and velocity distribution in order to achieve a high mass resolution in the time-of-flight mass spectrometer. This conditioning of the primary ion beam can be achieved by using the collision cell according to the invention.
A collision cell according to the invention can be operated both in continuous mode and also in a pulsed mode. The pulsed mode injects a predefined quantity of parent ions, allows them to oscillate backwards and forwards in the collision cell preferably without significant DC voltage drop until their kinetic energy has been absorbed by cooling or fragmenting collisions, and then empties the collision cell by increasing the decreasing DC voltages. The ions are then transported to the output, where they collect in the ion pool and can escape monoenergetically through the potential minimum in the center of the apertured diaphragm system. The pulsed mode can be repeated here for every spectrum of the time-of-flight spectrometer; fragmentation, thermalization and emptying must then take place very quickly. With a scan rate of ten kilohertz, each pulse operation must be completed in 100 microseconds, something which is only possible with very high collision gas pressures and which requires the DC voltages to be increased very rapidly. The quality of the beam suffers as a result, even with a scan rate of three kilohertz, the voltages of DC voltage drop and the apertured lens system must be very carefully matched in order to obtain a well-conditioned ion beam.
It is also possible to choose a slow pulsed mode in which one pulse encompasses the scan of a total of around 1000 individual spectra for a daughter spectrum, the daughter spectrum being scanned in around a tenth of a second.
It is also possible, however, to have pulsed operation with a period of around five milliseconds. In this case, the parent ions are injected for around a millisecond, for example out of an ion pool in the preceding selective quadrupole system. The ions then get around two milliseconds for fragmentation, thermalization and collection in the ion pool. This requires a collision gas pressure of around one to ten Pascal. After this, the ions are allowed to flow out of the ion pool for around two milliseconds, whereby the potential gradient of the ion pool is continuously increased, until the ion pool is practically empty. The emptying of the ion pool is shown schematically in FIG. 6 in several phases. Residues in the ion pool are not a problem, since immediately afterwards, a new filling period with the same parent ions begins.
This method of emptying the ion pool should produce excellent results with respect to the energy homogeneity and the composition of the ions. With longer collection phases, the heavy and the light ions in the ion pool segregate because the action of the pseudopotentials is mass-dependent. Collection phases which are too long when there is a good supply of ions then lead to a loss of heavy ions.
A pulsed mode of this type does not use the subsequent time-of-flight mass spectrometer to the full. The spectra are only ever taken for an interval of two milliseconds in a period of five milliseconds, the scanning of the spectra therefore occurs only 40% of the time. This has the effect of reducing the dynamic measuring range by a factor of 2.5. Nevertheless, this type of operation has proven to be advantageous for the resolution of the spectra and the accuracy of the mass spectra. If the total duration of the scan of a daughter ion spectrum is a tenth of a second, then with ten kilohertz scanning frequency, only 400 instead of 1000 daughter ion spectra are scanned and added. However, since the daughter ion spectra, which, after all, only utilize a fraction of the ions allowed into the mass spectrometer, practically never fully extend the ion detector and the digitalization electronics, this mode is desirable.
Knowledge of this invention makes it possible for those skilled in the art to set up yet more modes of operation for other types of analytical tasks using analogous methods. | The invention relates to a method for damping the kinetic energy of ions in ion cells filled with collision gas and with an exit aperture to drain the ions out of the cell. The invention uses a conditioning cell with an adjustable DC potential which decreases towards the exit aperture to compress the phase volume of the ions by damping their kinetic energies, collecting the ions after thermalization in the spatial potential minimum thus created and letting them drain away relatively slowly through a central potential minimum in the exit aperture system. This facilitates the production of very fine, highly parallel ion beams which consist of almost monoenergetic ions. In particular, the method can also be coupled with a fragmentation of the ions. | 49,635 |
FIELD OF THE INVENTION
This invention provides method and apparatus for rebuilding nominally disposable toner cartridges commonly used in electrostatic printers and copiers.
BACKGROUND OF THE INVENTION
It is common practice in the office printer and copier industry to make a lower priced copier or printer with a toner dispensing portion that is nominally a disposable cartridge. This cartridge commonly includes a toner bin, as well as a combination of a doctor blade and a gear-driven magnetic roller that is used to meter the toner onto a charged photoconductive surface.
The cost of replacing nominally disposable cartridges can be a significant fraction of the total cost of ownership. These cartridges commonly retail for 10-20% of the price of a new printer or copier. This high cost has given rise to an entire sub-industry of toner cartridge recyclers who recharge (and sometimes rebuild) the cartridges for a fraction of their new cost.
Although a cartridge can be refilled with toner many times, the precise mechanical and electrical components of the toner cartridge wear out and soon produce a visible degradation of copy quality. Since the cartridge is designed with the expectation of a short service life, serious wear problems can be encountered after only a few rechargings. Diagnosing just what wear mechanism causes which sort of copy degradation is a challenge for the re-builder, who must seek for his answers in an area unanticipated by the original designers. An example of such a diagnostic and corrective procedure is presented in a related patent application by the inventor. In his U.S. application, Ser. No. 07/823,290, the disclosure of which is herein incorporated by reference, the inventor described method and apparatus for maintaining copy quality by providing a substitute for a worn electrical contact to the toner roller.
One of the quality issues that has not been successfully addressed by the toner cartridge re-building industry is that of the "right side problem" in which a dark streak or gray background appears towards the right side of the imprinted surface of a piece of paper that has been processed through an affected electrostatic copier or printer. Re-builders have observed that when a printer or copier exhibits this effect, there is usually a build-up of excess toner on the corresponding "right side" of the corona wire (located adjacent the toner roller). Toner build-up on the corona wire can partially electrostatically shield the photoconductive drum, which prevents the corresponding "right side" of the photoconductor surface from being fully charged thus causing the observed dark streak on the right side of the paper.
Some re-builders have hypothesized that excess toner is blown onto this portion of the corona wire by a cooling fan (an exhaust vent for the air stream is normally adjacent the "right side" end of the corona wire) and have suggested placing a permanent magnet adjacent the corona wire to preferentially capture the toner (which is ferromagnetic) that would otherwise get on the wire.
The inventor has found no one in the industry who has suggested solving the "right side" problem by controlling the gap between the doctor blade and the toner roller and thereby preventing excess toner from getting out of the cartridge in the first place. This is not surprising, since (as will become apparent in the following discussion) the gap may open excessively only during printer operation, but remain within specification when the unit is at rest.
SUMMARY OF THE INVENTION
It is an object of the invention to reduce excess toner deposition near the right side of the image-bearing surface of a sheet of paper that has been processed through an electrostatic printer or copier.
It is a further object of the invention to reduce toner consumption in an electrostatic printer or copier.
It is an object of the invention to provide a method of rebuilding a worn toner cartridge so as to assure a uniform and accurately set gap between the doctor blade and the toner roller of the rebuilt cartridge.
It is a specific object of the invention to provide a bearing and a method of installing that bearing in place of a worn factory-installed bearing on a toner roller in order to extend the service life of a dry toner cartridge in an electrostatic printer or copier.
It is yet a further object of the invention to allow rebuilding of a toner cartridge without having to place a magnet near the corona wire in order to capture excess toner.
It is yet a further object of the invention to provide an indication of bearing wear to a toner cartridge recharger.
DESCRIPTION OF THE DRAWING
FIG. 1 of the drawing is a front plan view of a toner cartridge in which the bearing of the invention is installed.
FIG. 2 of the drawing is a side elevational view of a prior art bearing.
FIG. 3 of the drawing shows two views of the improved bearing. FIG. 3a is a side elevational view of one version of the improved bearing, with selected regions shown with distorted sizes for the sake of illustration. FIG. 3b is cross-sectional view taken through the section marked with reference numeral 76 in FIG. 3a.
FIG. 4 of the drawing is a side elevational view of a second version of the improved bearing, with selected regions distorted for the sake of illustration.
FIG. 5 of the drawing is a cross-section taken on a plane indicated as 70--70 in FIG. 1. FIG. 5a-b illustrate two steps in the process of installing the bearing of the invention into a housing after the bearing has been placed on the toner roller shaft.
DETAILED DESCRIPTION
Turning now to FIG. 1 of the drawing, one finds a toner cartridge typical of those that may be re-built according to the invention. A cartridge body 10 holds a doctor blade 12 and a toner roller 15. The doctor blade 12 can be fastened to the cartridge body 10 with a variety of screws, locating bosses, and the like that are well known in the art and that allow the edge of the blade 12 to be set parallel to the axis of the toner roller 15 and a controlled distance (e.g. 0.008-0.010") from the surface of the roller 15. The toner roller 15 is held in position in the cartridge body by bearings 18, 20 at either end thereof, and is rotated about its axis by means of a gear 22.
Satisfactory precision in metering the dry toner onto the roller requires a carefully set gap of approximately 0.008"-0.010" between the doctor blade 12 and the toner roller 15. The requisite precision can be readily attained during original equipment manufacture, and is normally held during the designed service life of the cartridge (i.e. in the absence of recharging). Progressive wear of the various components of the cartridge eventually leads to an uncontrolled and asymmetrical gap width, as will be subsequently discussed.
It is noteworthy that the two bearings 18, 20 have entirely different wear characteristics and wear mechanisms. The un-driven end bearing 18 outlasts the driven end bearing 20, which is subject to other forces that will be subsequently described. For the purposes of this disclosure, the service life of the un-driven end bearing 18 is of no concern, and the teachings herein presented will be directed at improvements to the driven-end bearing 20.
Turning now to FIG. 2 of the drawing, one finds an end view of a prior art version 20a of the driven-end bearing 20. The bearing 20a is generally a radially truncated disk that has outer 26 and inner 27 walls separated by a thinner web 28 region. The bearing 20a has a cylindrical inner bearing surface 30 that has a radius slightly greater than the end shaft 31 of the toner roller 15 about which it fits so that the bearing 20a can be easily slid onto the shaft 31 during assembly. The bearing 20a has a concentric outer cylindrical surface portion 32 that fits into a cylindrical bearing retainer 34 that is part of the end cap 24. The inner and outer surfaces of an OEM bearing (e.g. FIG. 20a) are separated by a predefined rear web width 29 that is marked with a double-headed arrow in FIG. 2. Since the bearing 20a can not extend substantially further outward than the toner roller 15 (i.e. the toner roller 15 needs to be brought into a close-spaced relation with the photoconductor surface so that it can donate toner to the charged photoconductor), the bearing 20a also has a generally flat outer surface portion 36 (i.e. the part of the bearing 20 that is visible in the elevation of FIG. 1).
Observations on bearings taken from used toner cartridges show that the inner surface 30 of the bearing 20 does not wear uniformly. Reaction forces to driving torques applied to the toner roller 15 by the driven gear 22, in combination with other forces (e.g. the weight of toner in the hopper) act to preferentially wear a portion 38 (shown in phantom in FIG. 2 of the drawing) that is approximately diametrically opposite that portion of the bearing 20 that is nearest the doctor blade 12. Thus, as wear progresses, the gap between the driven-end of the toner roller 15 and the doctor blade 12 becomes wider during the operation of the printer or copier. (The inventor has measured a gap of as much as 0.016" adjacent the driven-side bearing 20 in a worn cartridge by restraining the roller from turning and applying pressure to the drive gear (i.e. by simulating the torques associated with driving the roller). The same cartridge had a gap of 0.008-0.010" adjacent the un-driven bearing 18). This wear-induced wedge-shaped gap allows excess toner to be donated to the "right side" of the photoconductor. Other excess toner drifts into the neighborhood of the corona wire and preferentially builds up on the "right side" of the corona wire. Thus it appears that preferential wear of a bearing on the toner roller is the principal cause of the "right side problem", which is perhaps more properly called the "driven-side problem" or "gear-side problem". The terms "right side" and "left side", as used above, rapidly become ambiguous unless one understands that they refer strictly to the named side of the image-bearing surface of a sheet of paper and, by inference, to corresponding portions of the mechanisms that process that paper.
Note that when the toner roller 15 is not being driven, the rear web width 29 of the bearing 20a holds the roller in the proper position so that a normal gap width is measured between the toner roller 15 and doctor blade 12 as long as the preferential wear 38 has not reduced the rear web width 29.
Turning now to FIG. 3a of the drawing, one finds an end view of a bearing 20b of the invention. The bearing 20b, like the bearing 20a that it replaces, is in the form of a radially truncated disk with an inner wall 40 and a surrounding body portion 42 that is shown in FIG. 3b as being of uniform thickness, but that may also be configured similarly to the webbed design shown in FIG. 2. The radius of the cylindrical inner surface 44 of bearing 20b is chosen to be essentially the same or larger than that of bearing 20a so that the replacement bearing 20b can be easily slid over the end shaft 31 of the toner roller 15.
One key improvement in the replacement bearing 20b is a radial slot 50 (preferably approximately 0.030" in width) that extends from the inner surface 44 to a generally flat portion 52 of the outer surface of the bearing 20b, the flat portion being a plane parallel to the cylindrical axis of the inner wall 44 of the bearing.
A second key improvement in the new bearing 20b is the provision of additional material 55 adjacent the outer prolate surface 58 of the bearing 20b. The additional material 55 can be seen from FIG. 3a to extend beyond the phantom surface 60 that would have been formed approximately ninety degrees of arc from the flat surface portion had the new bearing 20b been made with the same outer radius as the cylindrical prior art bearing 20a. This additional material 55 may preferably add approximately 0.004" to 0.008" to the prolate radius of the distorted cylindrical outer surface 58 of bearing 20b.
It should be noted that the additional material 55 of the bearing 20b may be provided by a variety of composite surface geometries. The outer surface 58 could, for example, be a section of right elliptical cylinder. In a preferred embodiment, however, the outer surface 58 is constructed using arcuate segments that are the surfaces of sections of right circular cylinders drawn about two axes 61, 62 that are displaced from the principal axis 78 of the bearing 20b along a fictitious line segment 90 parallel to the flat face 52 of the bearing 20b. This construction, shown in FIGS. 3a and 3b of the drawing, provides the additional material 55 while maintaining the same rear web width 29 as was found in the OEM bearing 20a that is to be replaced.
Another feature of the new bearing 20b is a small locking ridge 65 on the outer bearing surface 58 adjacent one end 66 of the generally flat portion 52 of the bearing 20b. The purpose of this locking ridge 65, which may preferably protrude approximately 0.002" above the surface 58, will be subsequently discussed. The ear 68 that constitutes the other end of the generally flat portion 52 of the bearing 20b is provided as a handle for the operator to used during installation of the bearing 20b.
Turning now to FIG. 4 of the drawing, one finds an elevational view of a second bearing 20c of the invention. The bearing 20c, like bearings 20a and 20b, is in the form of a radially truncated disk with an inner wall 40 and a surrounding body portion 42. The inner surface 44 of bearing 20c is the same as that of bearing 20b discussed above, i.e. it is a section of a circular cylinder with an axis indicated with reference numeral 78 in FIG. 4. The outer surface 80 of bearing 20c is also cylindrical, but has a second axis 82 and a larger radius, which are chosen so as to provide the additional material 55 (shown as lying between the outer bearing surface 80 and a phantom right cylindrical surface 84, formed about the first cylindrical axis 78) while keeping the critical rear web width (indicated by a double headed arrow 29 in FIG. 4) between the first cylindrical axis 78 and the outer surface 80 of the bearing the same as it was for the OEM bearing 20a shown in FIG. 2.
Although the bearing 20c is shown, for purposes of illustration, in FIG. 4 as having two dramatically disparate cylindrical radii, the actual differences in radii and in axial positionings are small. In the preferred construction, the outer cylindrical bearing surface 80 has a radius approximately 0.005" greater than that of the inner cylindrical surface 44--i.e. the second cylindrical axis 82 is displaced only about 0.005" from the first cylindrical axis 78 along a fictitious line segment 92 that runs from the axis 78 to the flat portion 52 of the bearing 20c.
Thus, the invention provides bearings 20b and 20c that can be viewed as having been derived from the OEM bearing 20a by adding additional material 55 to a portion of the outer surface 32 of bearing 20a, where that portion lies between a phantom outer surface 60 and a cylindrical section formed about an axis that may be translated from the cylindrical axis 78 of the original bearing 20a. The translation may be in a variety of directions, including parallel to the flat surface portion 52 (bearing 20b) or perpendicular to the flat surface portion (bearing 20c).
The purposes of the various features of the new bearings 20b and 20c can be understood more clearly by considering the steps involved in using a new bearing 20b in re-building a toner cartridge (the use of 20c is identical). In disassembly of the worn cartridge, one would, inter alia, remove the gear-driven end of the toner roller from the cartridge body 10 by first removing the cartridge end cap 24 by pulling it to the left in the view shown in FIG. 1 (note that in many toner cartridge designs, the cartridge end cap includes a cylindrical sleeve that serves as the bearing retainer 34). One then twists the roller 15 from the body 10 and slides the gear 22 off a flattened portion of the toner roller shaft 31, and slides the bearing 20 off the shaft 31. On re-assembly, one would proceed in reverse order, and would place the new bearing 20b on the shaft 31 so that the ear 68 faced away from the bearing housing 34 (This position is shown in FIG. 5a of the drawing, which is a cross-section along a line indicated by the reference numeral 70 in FIG. 1.). In the view of FIG. 1, the ear 68 would be positioned so as to extend outward from the toner roller 15--i.e. out of the plane of the drawing of FIG. 1). Then after re-inserting the toner roller 15, one would push the end cap 24 into a recess in the toner cartridge body 10.
When in the position shown in FIG. 5a of the drawing, the new bearing 20b can be slid easily into position. The diameter of the inner surface 44 is at least as great as that of the original equipment manufacturer's bearing 20a, so the bearing 20b slides freely onto the shaft 31.
Once the above recited components of the toner cartridge are assembled, the new bearing 20b can be rotated into its seated position (shown in FIG. 5b) by pushing on the ear 68 (e.g. by pushing downward in the view of FIG. 1). In this position, the excess diameter of the outer bearing surface 58 of the new bearing 20b is rotated into a zero tolerance fit in the bearing housing 34. As the bearing 20b is wedged into the housing 34, the slot 50 is forced partially closed, thus securing a zero tolerance fit at both the inner 44 and outer 58 bearing surfaces of the improved bearing 20b. If, as is commonly the case, the bearing retainer 34 is in the form of a relatively thin cylindrical shell, the act of rotating the new bearing 20b or 20c into its locked position can force the walls of the bearing retainer 34 outward so as to obtain a zero tolerance fit between the bearing retainer 34 and the body 10 of toner cartridge (e.g. as shown in FIG. 5b).
The proper position for the bearing 20b can be felt by the installer when the locking ridge 65 is rotated past the end 72 of the bearing housing wall 34 and snaps perceptibly into place.
It should be noted that a further benefit of the improved bearing of the invention is that a zero tolerance fit is maintained even as the bearing wears. When the inner surface 44 of the new bearing 20b wears, the compressive forces resulting from jamming the bearing 20b into the housing 34 will cause the slot 50 to shrink further, and maintain the zero tolerance fit. Thus, for a given combination of OEM bearing 20a, housing 34 and replacement bearing 20b, one can select the width of the slot 50 so that the flat faces 74 that bound the slot are a first predetermined distance apart (e.g. 0.030") prior to installation; a second predetermined distance (e.g. 0.020") when first installed; and a third predetermined distance (e.g. 0.015") when the replacement bearing 20b is worn out. Whenever the cartridge is recharged with additional toner these gap widths can be easily checked without disassembling the cartridge to make the measurement.
Alternately, of course, one could choose the dimensions of the improved bearings 20b, 20c so that the slot 50 closed completely when the bearing was installed. In comparison with the approach described above, this "zero gap" approach would provide a more nearly cylindrical inner bearing surface for the toner roller 15 when the bearing was first installed. The disadvantages of the "zero gap" approach are, of course, that there would be no change in gap width to indicate wear, and wear would result in a greater amount of lateral "play" in the toner roller 15 over the service life of the bearing.
The improved bearings taught herein provide means of rebuilding a toner cartridge so that excess toner does not pass through a wedged and enlarged gap between the doctor blade 12 and the toner roller 15. This solves the "right side problem" and reduces the amount of toner used.
Although the present invention has been described with respect to a preferred embodiment, many modifications and alterations can be made without departing from the invention. Accordingly, it is intended that all such modifications and alterations be considered as within the spirit and scope of the invention as defined in the attached claims.
What is desired to be secured by Letters Patent is: | A replacement bearing is provided for use in rebuilding the nominally disposable toner cartridges that are commonly used in popularly priced electrostatic printers and copiers. When the bearing is rotated into its final position about the shaft of a toner roller, an oversize portion of the bearing is forced into a position that ensures that both the bearing retainer and the toner roller are restrained in a precise alignment. A slot, that has a predetermined gap when installed, is preferably provided in the bearing, and a decrease of the width of this gap is indicative of bearing wear. The precise alignment and wear indication means that are provided by the new bearing allow an operator to rebuild a toner cartridge that had been demonstrating the "right side problem", and to subsequently monitor the wear of a replacement bearing so as to prevent recurrence of copy degradation. | 20,868 |
CROSS-REFERENCES TO RELATED APPLICATIONS
[0001] This application claims priority under 35 U.S.C. §119 (e) to, and hereby incorporates by reference, U.S. Provisional Application No. 60/238,668, filed Oct. 6, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention is directed to substances for suppressing scents. More particularly, this invention is directed to liquid formulations applied to articles of attire, footwear, and equipment to prevent a person's scent from emanating therefrom.
[0004] 2. Background of the Invention
[0005] It is unavoidable that persons generate and give off odors (or scents). These odors may originate from sources such as natural body secretions (perspiration, oils), bacteria residing on the skin, and clothing worn by the individual.
[0006] Many animals, such as bear, deer, elk, and fox, have highly developed abilities to detect a person in proximity by sensing the person's odor. Therefore, persons hunting and observing these animals, in addition to visual camouflage, often attempt to prevent these animals from sensing odors characteristic of humans. To this end, several liquid and cream formulations are applied to the user's skin for masking or camouflaging the person's scent. Other substances are applied during bathing to temporarily remove the user's scent. Liquid formulations are also applied to garments worn by these persons to reduce odors. These liquid formulations have been proven to be effective in preventing the user's body odor from being detected by game. These liquid formulations typically contain ingredients for preventing or minimizing formation of odor causing chemical compounds. However, a liquid formulation suitable to be applied to clothing, footwear, and equipment with longer lasting and even more effective odor-suppressing properties would be even more desirable. There then is a need for a long lasting, odor-suppressing liquid formulation, which can be applied to apparel worn when hunting or observing animals and which can suppress odors caused by chemical compounds already present.
SUMMARY OF THE INVENTION
[0007] This invention substantially meets the aforementioned needs of the industry by providing a liquid formulation suitable to be applied to an article of apparel, the article of apparel to be worn by, or to be in close contact with, a person hunting or observing game or otherwise used to prevent game from sensing the user's scent. The present liquid formulation may also be advantageously applied to articles of equipment and with beneficial effects similar to those effects encountered when used on articles of apparel. When the present liquid formulation is applied to textiles and other materials used in making apparel, game animals are much less likely to detect the user. One way in which these odors are suppressed is by adsorbing odor-producing substances. Moreover, the liquid formulation of this invention may contain a substance which inhibits odiferous substance formation.
[0008] One embodiment of the present scent-adsorbing liquid formulation includes an alkali metal carbonate or bicarbonate salt, and a particulate, odor-adsorbing agent such as activated carbon. In another embodiment, a preservative may be included. The preservative may include a substance with antimicrobial activity. A nonionic surfactant, such as an alkylaryl polyether alcohol, may also be present in an amount sufficient to allow the preservative to be incorporated into the formulation as a solution, suspension, or emulsion and/or to allow for better coverage when applied to the article of apparel. The liquid formulation may further include a base, such as an alkali metal hydroxide, in an amount sufficient to provide a formulation pH between about 9 and 11. An alkaline pH may be advantageous in promoting penetration or coverage of the substance being treated, in retarding formation of some odiferous substances per se, and in providing an environment in which the preservatives are most effective in inhibiting bacterial (or generally microfloral) growth and development.
[0009] It is one feature that the present liquid formulation suppresses odors otherwise emanating from users by providing an adsorptive agent, such as particulate activated carbon. The liquid formulation is applied to an article of attire or other object worn by, or in close contact with, the user. The adsorptive agent adsorbs odiferous substances given off by the user which otherwise become airborne and would be detected by animals.
[0010] It is a second feature of this invention that some embodiments of the present liquid formulation may also inhibit or retard generation of odiferous substances by containing a preservative, such as an antimicrobial agent. The preservative, when applied to an item of apparel or an article to be in close contact with a user, stops or inhibits microflora (such as bacteria) from producing odiferous substances, which might otherwise be detected by animals.
[0011] It is a third feature of this invention that the present liquid formulation can be applied to garments worn by a user while hunting or observing game animals. When garments to which the present liquid formulation is applied are worn, the likelihood of being scented by the game animals is minimized. Stated otherwise, the likelihood of game animals moving into near proximity with the wearer of apparel treated by the present liquid formulation is maximized because of eliminated or greatly reduced odors emanating from the wearer.
[0012] Additional objects, advantages, and features of various embodiments of this invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art. The objects and advantages of various embodiments of this invention may be realized and attained by persons of ordinary skill in the art by means of the instrumentalities and combinations particularly pointed out in the description below.
DETAILED DESCRIPTION OF THE INVENTION
[0013] The present invention is a substantially liquid formulation suitable to be applied to fabrics or other articles of apparel, footwear, and items of equipment. These articles, when the present liquid formulation has been applied thereto, effectively prevent game animals from detecting a wearer's body odor or scent.
[0014] The term “substantially liquid formulation” is contemplated to describe formulations which may contain nonliquid ingredients, but can nonetheless be applied by methods used to apply other liquids after the nonliquid ingredients are suspended, e.g., by agitation. One such method of application is by using a spray bottle.
[0015] The present invention may include an odor-adsorbing material, the odor-adsorbing material suspendable (or otherwise included) in an aqueous solution (or emulsion). The present formulation may also include one or more preservatives (to include one or more antimicrobial formulations), an alkali metal carbonate or bicarbonate, one or more surfactants, and/or an alkali metal hydroxide. Powdered activated carbon may be advantageously suspended in this liquid formulation. Optionally, a dye is included. Unless otherwise specified, ingredient proportions are stated in percent by weight of the final product.
[0016] Preservatives
[0017] Suitable preservatives for use in the present formulation include:
[0018] 1. Alkali metal salts of C 2 -C 6 carboxylic acids, e.g., sodium propionate (Niacet Corporation).
[0019] 2. Derivatives of imidazoles, e.g., imidazolidinyl urea (Tristad 1U, Tri-K Industries).
[0020] 3. Mixtures of esterified phenols and phenol derivatives, e.g., methylparaben, propylparaben, and diazolidinyl urea (Germaben 2, Sutton Labs).
[0021] 4. Organic sulfur compounds.
[0022] a. 3-isothiazolones and salts formed by reactions with acids such as hydrochloric, nitric, and sulfuric acids; e.g., 5-chloro-2-methyl-4-isothiazolin-3-one; 2-n-butyl-3-isothiazolone; 2-benzyl-3-isothiazolone; 2-phenyl-3-isothiazolone, 2-methyl-4,5-dichloroisothiazolone; 5-chloro-2-methyl-3-isothiazolone; 2-methyl-4-isothiazolin-3-one; and mixtures thereof. An exemplary broad spectrum 3-isothiazolone preservative is available as Kathon® CG by Rohm and Haas Company.
[0023] b. Sodium pyrithione and mixtures of organic sulfur compounds.
[0024] 5. Halogenated compounds.
[0025] a. 5-bromo-5-nitro-1,3-dioxane (e.g., Bronidox L® from Henkel).
[0026] b. 2-bromo-2-nitropropane-1,3-diol, (e.g., Bronopol® from Inolex).
[0027] c. 1,1′-hexamethylene bis(5-(p-chlorophenyl)biguanide), commonly known as chlorhexidine and its salts.
[0028] d. 1,1,1-trichloro-2-methylpropan-2-ol, commonly known as chlorobutanol.
[0029] e. 4,4′-(trimethylenedioxy)bis-(3-bromobenzamidine) diisethionate or dibromopropamidine.
[0030] 6. Cyclic organic nitrogen compounds.
[0031] a. Imidazolidinedione compounds.
[0032] i. 1,3-bis(hydroxymethyl)-5,5-dimethyl-2,4-imidazolidinedione, commonly known as dimethyloldimethylhydantoin, or DMDM hydantoin, available as, e.g., Glydant® from Lonza.
[0033] ii. N-[1,3-bis(hydroxymethyl)2,5-dioxo-4-imidazolidinyl]-N,N′-bis(hydroxymethyl) urea, commonly known as diazolidinyl urea, available under the trade name Germall II® from Sutton Laboratories, Inc.
[0034] iii. N,N″-methylenebis {N′-[1-(hydroxymethyl)-2,5-dioxo-4-imidazolidinyl]urea}, commonly known as imidazolidinyl urea, available, e.g., under the trade name Abiol® from 3V-Sigma, Unicide U-13® from Induchem, Germall 115®.
[0035] b. Polymethoxy Bicyclic Oxazolidine, such as Nuosept® C from Huls America.
[0036] 7. Low Molecular Weight Aldehydes.
[0037] a. Formaldehyde.
[0038] b. Glutaraldehyde.
[0039] 8. Cationic and/or Quaternary Compounds.
[0040] a. Polyaminopropyl biguanide, also known as polyhexamethylene biguanide, such as Cosmocil CQ® from ICI Americas, Inc., or Mikrokill® from Brooks, Inc.
[0041] b. 1-(3-Chlorallyl)-3,5,7-triaza-1-azoniaadamantane chloride, available, e.g., Dowicil 200 from Dow Chemical.
[0042] 9. Dehydroacetic Acid.
[0043] 10. Phenyl and Phenoxy Compounds. Some non-limiting examples of phenyl and phenoxy compounds suitable for use in the present invention are:
[0044] a. 4,4′-diamidino-.alpha.,.omega.-diphenoxypropane diisethionate, commonly known as propamidine isethionate.
[0045] b. Benzyl alcohol.
[0046] c. 2-phenylethanol.
[0047] d. 2-phenoxyethanol.
[0048] The preservative or preservatives may be present in an amount between about 0.025% and 5%, 0.025% and 2.5%, 0.025% and 1%, or any range subsumed therein.
[0049] Surfactants
[0050] A variety of surfactants may be useful in the present invention. These surfactants are contemplated to include nonionic, anionic, and/or cationic surfactants. These surfactants may facilitate the inclusion of other substances in the present formulation as solutions, dispersions, and/or emulsions. These surfactants may also enable more complete coverage when the present formulation is applied to articles of attire.
[0051] Nonlimiting examples of nonionic surfactants which may be suitable for use in embodiments of this invention are recited below.
[0052] 1. Nonylphenol ethoxylates with 4-100 ethylene oxide groups per nonylphenol molecule.
[0053] 2. Dinonylphenol ethoxylates with 4-150 ethylene oxide groups per dinonylphenol molecule.
[0054] 3. Linear alcohol ethoxylates with the alcohol chain consisting of 2-24 carbon atoms and with 2 to 150 ethylene oxide groups per alcohol molecule.
[0055] 4. Dodecylphenol ethoxylates with 4-100 ethylene oxide groups per dodecylphenol molecule.
[0056] 5. Octylphenol ethoxylates with 4-100 ethylene oxide groups per octylphenol molecule.
[0057] 6. Alkanolamides in which the carbon chain includes a C 6 -C 18 fatty acid reacted with monoethanolamine, diethanolamine or isopropanolamine.
[0058] 7. Ethoxylated alkanolamides in which the carbon chain consists of a C 6 -C 18 fatty acid reacted with ethylene oxide and monoethanolamine, diethanolamine or isopropanolamine.
[0059] 8. Amine oxides having a carbon chain from C 6 to C 18 .
[0060] 9. Fatty acid ethoxylates with 2-40 ethylene oxide groups per fatty acid molecule where the fatty acid has a carbon chain from C 4 to C 18 .
[0061] 10. Ethylene oxide/propylene oxide (eo/po) block copolymers with average molecular weights of between 500 and 15,000.
[0062] 11. Nonylphenol ethoxylate propoxylates with average molecular weights between 400-8000.
[0063] 12. Alkylaryl polyether alcohols prepared by reacting octylphenol with ethylene oxide, e.g., octylphenoxypolyethoxyethanol with between about 1-70, 7-40, 9-30, or 9-10 ethylene oxide groups per molecule, e.g., Triton X-100 (Van Waters and Rogers).
[0064] 13. Linear alcohol alkoxylates (e.g., ethoxylates, propoxylates) with average molecular weights between 400-8000 and carbon chains from C 8 to C 18 .
[0065] Anionic surfactants which could be included in the present invention include, but are not limited to, the following examples.
[0066] 1. Alkyl sulfonate salts and alkylaryl sulfonate salts supplied with sodium, potassium, ammonium, protonated monoethanolamine, diethanolamine, or triethanolamine or protonated isopropanolamine cations, such as the following salts.
[0067] a. Linear primary C 6 -C 18 sulfonate salts.
[0068] b. Linear secondary C 3 -C 18 sulfonate salts.
[0069] c. Alpha olefin sulfonate salts.
[0070] d. Dodecylbenzene sulfonate salts.
[0071] e. Tridecylbenzene sulfonate salts.
[0072] f. Xylene sulfonate salts.
[0073] g. Cumene sulfonate salts.
[0074] h. Toluene sulfonate salts.
[0075] 2. Alkyl sulfate salts and alkylaryl sulfate salts supplied with Na, K, NH 4 , protonated monoethanolarnine, diethanolamine, or triethanolamine, or protonated isopropanolamine cations, such as the following salts.
[0076] a. Linear primary C 6 -C 18 sulfate salts.
[0077] b. Linear secondary C 3 -C 18 sulfate salts.
[0078] c. C 12 -C 13 benzene sulfate salts.
[0079] 3. Alkyl C 6 -C 18 naphthalene sulfonate salts with Na, K or NH 4 cations.
[0080] 4. Alkyl C 6 -C 18 diphenyl sulfonate salts with Na, K or NH 4 cations.
[0081] 5. Alkyl ether sulfate salts or alkylaryl ether sulfate salts supplied with Na, K, NH 4 , protonated monoethanolamnine, diethanolarnine, or triethanolamine, or protonated isoprponolamine cations, such as the following salts.
[0082] a. Alkyl C 8 -C 18 alcohol (ethoxylate) 1-6 sulfate salts.
[0083] b. Alkyl C 8 -C 12 phenoxy (ethoxylate) 1-12 sulfate salts.
[0084] 6. Alkyl ether sulfonate salts or alkylaryl ether sulfonate salts supplied with Na, K, NH 4 , protonated monoethanolamine, diethanolamnine or triethanolamine or protonated isopropanolamine cations, such as the following salts.
[0085] a. Alkyl C 8 -C 18 alcohol (ethoxylate) 1-6 sulfonate salts.
[0086] b. Alkyl C 8 -C 12 phenoxy (ethoxylate) 1-12 sulfonate salts.
[0087] 7. C 4 -C 18 dialkyl sulfosuccinate salts supplied with Na, K, NH 4 , protonated monoethanolamine, diethanolamine, or triethanolamine or protonated isopropanolamine cations, such as disodium dioctyl sulfosuccinate.
[0088] 8. Other anionic surfactants such as monoalkyl phosphate ester salts, dialkyl phosphate ester salts, isothionates, or taurate salts.
[0089] Cationic surfactants can also be used in the present composition. By way of illustration and not limitation, suitable cationic surfactants may include quaternary ammonium compounds selected from mono C 6 -C 16 , C 6 -C 10 N-alkyl, or alkenyl ammonium surfactants, wherein the remaining N positions are substituted by methyl, hydroxyethyl or hydroxypropyl groups.
[0090] Surfactants may be present in the present formulation in concentrations of between about 0.010% and 5%, 0.015% and 2.5%, 0.020% and 1%, or any range subsumed therein.
[0091] Adsorbing Agent
[0092] The odor-adsorbing agent of this invention may have a particle size range sufficiently small to be suspended easily and to pass through spray dispensers. One method of making a suitable activated carbon is to carbonize a starting material (e.g., coconut shells, coal, wood, soybean hulls, almond hulls, hazel nut shells, black walnut shells, Brazil nut shells, macadamia nut shells) at a high temperature in an inert atmosphere. The carbonized coconut shells are then steam activated at 800° C. to 1000° C. In many cases, the foregoing produces activated carbon with an internal surface area of from 900 square meters per gram to 1500 square meters per gram. Suitable activated carbons include those sold as 208C 4×8, 607 4×6, HR5 12×40, HR5 AW 12×40, 206A 12×40, 207A 4×10, and 207AW 12.40 (Bamebey and Sutcliffe). However, other adsorbents which might be suitable in mixtures with the foregoing or as sole adsorbents include modified clay media (e.g., 30% organically modified bentonite clay and 70% anthracite or activated carbon), bone char adsorbent, and impregnated activated carbon. If used in the present formulation, activated carbon may be present in an amount of about 1.0% or 1.5% or in amounts between about 0.10% and 5%, 0.20% and 2.5%, 0.70% and 2.00%, or any range subsumed therein.
[0093] Alkali Metal Carbonates/Bicarbonates
[0094] The alkali metal carbonate or bicarbonate used in the present formulation may be effective in suppressing and/or adsorbing odors and scents. Suitable alkali metal salts of this nature include sodium and potassium carbonates and bicarbonates and be present in amounts between about 0.01% and 5%, 1% and 5%, 2% and 4%, or any range subsumed therein.
[0095] Base
[0096] A base, such as an alkali metal hydroxide (e.g., Na OH) may be present in the formulation of this invention. The base will adjust the pH of the present formulation to between about 7 and 13, 8 and 12, 9 and 11, or any pH at which the present formulation disperses on textiles and effectively adsorbs and/or prevents the wearer's scent or odors from emanating therefrom. Thus, in some embodiments the base may be present in an amount between about 0.1% and 5.0%, 0.2% and 2.5%, 0.25% and 1.0%, or any range subsumed therein.
[0097] One way of making the present formulation is to add the preservatives, alkali metal carbonate or bicarbonate, surfactants, and base (if present) to a predetermined volume of water (e.g., deionized). The foregoing ingredients may be mixed or agitated until they are either in solution or emulsified. Undissolved ingredients and particulate impurities may then be removed by passing the solution through one or more filters (e.g., 10, 5, 1 micron). Finally, the odor-adsorbing agent is added and suspended (e.g., by agitation). Optionally, a dye may be added to the solution before or after the filtration step. A suitable black dye may be obtained from Keystone Corporation. The dye may be present in an amount such that the present formulation can be detected when applied to textiles, e.g., 0.01% -1.0%, or any range subsumed therein.
[0098] When being used, the present formulation may be agitated to the extent necessary to resuspend any settled activated carbon particulates. The present formulation may be applied as a spray or mist application to any desired surface. From four to five ounces of the present solution can be spray-applied to an individual garment. Alternatively, 128 (±4) ounces can be applied to a garment dipped in the present solution. For example, the present formulation may be sprayed on apparel such as clothing and boots, or on hunting gear and equipment. When applied thusly, the solution permeates the fibers and/or pores of the clothing, boots, and equipment. The solution may also be applied to the surfaces of equipment made of wood, metal, plastic, and composites. Moreover, the present formulation may be applied by immersing the article therein. After being applied, the solution dries and is actively present on the surface until washed or worn away. The present formulation may be applied as frequently as desired during use.
EXAMPLE I
[0099] Samples of 1) a test scent blocking formulation of the present invention (denoted below as A) and 2) a test scent blocking formulation of the prior art (denoted below as B) were tested for sorption capacity. The test scent blocking formulations had the ingredients shown below in Table 1.
TABLE 1 Ingredients Present in Test Scent Blocking Formulations of the Present Invention (A) and the Prior Art (B). A (%) B (%) Deionized water 96.036 96.591 Sodium bicarbonate 1 2.000 3.000 Sodium hydroxide 0.189 0.189 Sodium propionate 0.050 0.050 Triton X 100 ® 0.025 0.020 Particulate activated carbon 2 1.500 — Glydant Plus ® 0.200 0.150
[0100] [0100] 1 pH9-11
[0101] [0101] 2 Minimum adsorption capacity 60% (w/w); particle size (powder) 325×F; minimum mean particle diameter 18 microns; maximum mean particle diameter 62 microns; D(90) micron particle size below which 90% of particles flow=165 maximum; derived from coconut shells
[0102] Two sets of test “spike” solutions were prepared at various levels in a 1% Triton X 100 aqueous solvent using compounds chosen from prior studies as associated with human odors. A first set of spike solutions contained known concentrations of butyric acid and isovaleric acid. Butyric and isovaleric acids are known to be present in human perspiration. (“Study of the Composition of Volatile Compounds of Human Sweat and Urine,” Savina et al., Kosm. Biol. Aviakosm. Med., 1975). A second set of spike solutions contained known concentrations of six non-acidic organic compounds. These non-acidic compounds were chosen for their chemical functionality and/or their documented presence in human perspiration or urine. The six compounds and their functional classes were an aldehyde, isovaleraldehyde (3-methylbutanal); an alcohol, 2-butanol; a ketone, 2-hexanone; an ester, ethylbutyrate (ethyl butanoate); a disulfide, dimethyl disulfide (2,3-dithiabutane); and an unsaturated hydrocarbon limonene (methyl-4-isopropenyl-1-cyclohexene). Aldehydes, alcohols, and ketones and acids are known to occur in human perspiration and urine. The ester, unsaturated hydrocarbon, and disulfide are also commonly found in various human use products.
[0103] Three pieces of 70 mm diameter filter paper (Whatman GF/A 41) were inserted into, then formed to cover the sides of, 40 mm VOA vials. The VOA vials with inserted filter papers were then dried for two hours at 85° C. The vials with dried filter papers and septum screw caps were weighed. The test scent blocking formulations were thoroughly shaken to mix them well before being added to two ml vials. The two ml vials were then rolled to coat the formulation evenly on the filter papers. The total volume of test scent blocking formulation dispensed into each two ml vial was held constant at 30 ul of total solution by adding 1% Triton X 100 throughout the sampling period as necessary. This ensured that the test formulation did not splash onto the filter paper and also minimized solvent effects in the system. The VOA vial was then sealed with a septum screw cap and allowed to stand for two hours at room temperature. The two hour period was to attain equilibrium with respect to vapor and liquid phases of the spike solution. After the two hour period, a 75 um Carboxen/PDMS solid phase micro extraction fiber (SPME fiber), available from Supelco as part #57318, was inserted through the septum of the cap and the headspace in the VOA vial was extracted for 30 minutes at room temperature. Following the SPME extraction, the SPME fiber was desorbed into a gas chromatography-mass spectrometry system (GCMS) and analyzed under the select ion monitoring (SIM).
[0104] The SPME fiber was then removed from the vial headspace, inserted into a GC injection port, and desorbed in the GC injection port for three minutes at 280° C. The following conditions were present with respect to the GCMS instrument:
Interface Temperature 280° C. Source Temperature 200° C. Injector Temperature 280° C. Initial Temperature 30° C. Initial Hold 3 min. Ramp Rate 6° C./min to 90° C., 20° C./min to 230° C., hold 3 min Column DB Wax (J&W, 30 m × 0.25 mm × 0.25 um). Mass Range SIM (Select Ion Monitoring) Solvent Delay 3.2 min Group 1 Start Time 3.2 min (mass, dwell) 44, 100 58, 100 Group 2 Start Time 6.0 min (mass, dwell) 45, 100 59, 100 71, 100 88, 100 Group 3 Start Time 7.2 min (mass, dwell) 43, 100 58, 100 79, 100 94, 100 Group 4 Start Time 8.2 min (mass, dwell) 68, 100 93, 100 Group 5 Start Time 11.5 min (mass, dwell) 60, 100 73, 100 87, 100 Group 6 Start Time 21.7 min 200, 100
[0105] Individual compound response factors were generated daily from at least a two point standard curve. The two point standard curve bounded the response of the compounds in the headspace of the VOA vial. Standards used were prepared by adding a known mass of the analytes to a blank VOA vial, extracting the headspace with the SPME fiber for 30 minutes, and analyzing desorbed standards under the same GCMS method used to analyze the samples. The daily response factors (area of the principal ion vs. mass of analytes added to a 40 ml VOA vial) were stored in a calibration file and were used to calculate the headspace concentration from the testing done in a given day.
[0106] Each formulation sample was prepared and analyzed at least three times. Concentrations of analytes remaining in the headspaces were calculated by applying the response factors generated the same day as the test was conducted. A blank vial containing only the dried filter paper and 30 ul of the Triton X 100 without analytes was shown to be free of interferences. The mass of each test compound sorbed by each treatment solution was calculated by the following equation:
Mass Sorbed=Mass Added by Spike−Mass Remaining in Headspace.
[0107] The analysis protocol was based on about 0.1 to 1.0 ug of each analyte remaining in the headspace after being sorbed for two hours (5-15 ug acids remaining). In order to achieve this endpoint, the mass of each non-acid analyte added to the closed systems was about 1 ug for the second scent blocking formulation (Table 2). In the case of the present sent blocking formulation, several hundreds of micrograms were added. The amount of the two acids was held constant at about 69 ug for each scent blocking solution because the sorption/neutralization capacity of each formulation for the acids was substantially the same.
TABLE 2 Mass (ug) of Analytes Added to Two Scent Blocking Solutions. A B Isovaleraldehyde 275 0.66 2-butanol 415 1.00 Ethylbutyrate 333 0.80 Dimethyl disulfide 354 0.85 2-hexanone 320 0.77 d-limonene 303 0.73 Butyric acid 68.7 68.7 Isovaleric acid 69.6 69.6
[0108] The sorption capacity results by individual compound (mean±standard deviation) are depicted in Table 3. Considering the capacity for all compounds spiked, the present formulation had about 15 times more capacity than the prior art formulation. Because the acid sorbing capacity was the same for both scent blocking solutions, the addition of activated charcoal was obviously the reason for the superior sorbing of the non-acid compounds by the present formulation A. Considering only the six non-acid compounds, the present formulation had about 1000 fold more sorptive capacity than the prior art formulation.
TABLE 3 Mean Sorption Capacity of Two Scent Blocking Solutions Analyte A B Isovaleraldehyde 274 (0.1) 0.1 (0.1) 2-butanol 413 (0.6) 0.7 (<0.1) Ethylbutyrate 333 (<0.1) 0.5 (<0.1) Dimethyl disulfide 354 (0.1) <0.1 (0.1) 2-hexanone 319 (<0.1) 0.4 (0.1) d-limonene 303 (0.1) 0.4 (0.1) Butyric acid 66 (2.9) 66 (2.8) Isovaleric acid 66 (2.9) 67 (2.7) Total All 2128 135 Compounds Total Non-Acids 1996 2.1
[0109] Four additional embodiments of the present odor inhibiting formulation are presented below in Table 7 as formulations C, D, E, and F.
TABLE 7 Ingredients Present in Test Scent Blocking Formulations of the Present Invention. E (%) F (%) G (%) H (%) Deionized water 95.500 95.050 92.500 96.675 Sodium bicarbonate 0.850 1.750 2.500 Potassium carbonate 1.000 Sodium hydroxide 1 2.500 1.500 2.000 Sodium Propionate 0.050 0.075 Glydant Plus ® 0.250 Triton X 100 ® 1.050 Particulate activated carbon 2 2.000 1.500 2.500 0.750
[0110] Because numerous modifications of this invention may be made without departing from the spirit thereof, the scope of the invention is not to be limited to the embodiments illustrated and described. Rather, the scope of the invention is to be determined by the appended claims and their equivalents. | An odor-absorbing liquid formulation, one embodiment thereof comprising a preservative, an alkali metal salt, and a particulate odor-adsorbing agent such as activated carbon. The formulation may further include an alkylaryl polyether nonionic surfactant and may have an alkaline pH. The present liquid formulation is applied to apparel to be worn during hunting or observation to avoid being sensed by animals. | 31,696 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a continuation-in-part of application Ser. No. 74/067698, filed on June 11, 1990.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the field of barbecue grills, and more specifically to a barbecue grill having multiple chambers for improved cooking capability and ease of use.
2. Description of the Prior Art
A barbecue grill with multiple chambers for cooking meat and other foodstuffs is known from U.S. Pat. No. 4,932,390 to the applicant of the instant invention, which is a further improvement of aforesaid U.S. patent.
The aforesaid multi-chambered grill has the drawback that the grilled foodstuffs must be removed from the barbecue and placed in serving trays and the like before eating. In this process the food tends to become cold before it can be eaten, and additional eating utensils are required to be cleaned and/or disposed of.
Other barbecue grills of known construction have a similar disadvantage. These include Fuss, U.S. Pat. No. 3,598,102, issued on Aug. 10, 1971, and Thompson, U.S. Pat. No. 3,657,996, issued on April 25, 1972.
Fuss also fails to provide any means for raising and lowering the cooking grill. In addition, one cannot rotate the Fuss cooking grill without in some way touching its burning hot surface. Thompson provides mechanisms for rotating, raising and lowering the grill. These mechanisms, however, involve complex arrangements of gears and brackets which are expensive and prone to jamming.
SUMMARY OF THE INVENTION
The present invention accomplishes the above-stated objectives, as well as others, as may be determined by a fair reading and interpretation of the entire specification.
It is accordingly a primary object of the instant invention to provide a barbecue grill that overcomes the drawbacks of the known barbecue grills.
In accordance with the objects of the invention there is provided a multi-chambered barbecue grill having a main chamber, a cooking grill located in the main chamber, a fire source located in the main chamber below the cooking grill, an ash chamber integral with or attached to the main chamber below the fire source for catching ashes, and a reversible top chamber located above the main chamber, adapted for receiving the cooking grill in its reversed position.
In accordance with a further object, there is provided a barbecue grill wherein the fire source is a grate for supporting burning coals, or wherein said fire source is a gas burner, including an arrangement for supplying cooking gas to at least part of the gas burner.
In accordance with a further feature, there is provided a barbecue grill including a divider on top of the grate, which divides the grate into at least two sections, wherein one or several sections may contain burning coals.
In accordance with another feature there is provided a barbecue grill including a cooking grill support for rotatably supporting the cooking grill, and wherein the cooking grill support includes a height-adjusting arrangement for adjusting the height of the cooking grill above the fire source.
There may further be provided a barbecue grill wherein the cooking grill support includes a support bracket disposed above the cooking grill and is rigidly attached thereto and has a threaded hole therein with an axis perpendicular to the cooking grill, an elongate threaded member having a lower end threadedly receivable in the threaded hole, an upstanding post aligned with the threaded hole attached to the grate or fire source for rotatably supporting the lower end of the elongate threaded member.
There may alternatively be provided a barbecue grill wherein the fire source is a grate for supporting burning coals and the ash chamber has an underside, additionally including a tubular member attached to the grate and extending upward perpendicular to the grate for supporting the cooking grill in its lowest position and a push rod member slidably contained within the tubular member, which bears against underside of the cooking grill, for raising and lowering the cooking grill, said push rod member extending through a hole in said ash chamber, and supported at any of several elevations by support means attached beneath the ash chamber.
There may be provided a barbecue grill wherein the support means includes a lever member pivotally mounted on fulcrum means secured to the underside of the ash chamber, one end of the lever member extending under and supporting the push rod member and the other end forming a handle for pushing the lever member down or up to raise or lower, respectively, the push rod member, the lever member being adjustably secured in any of several positions by adjustment means.
There may be provided a barbecue grill wherein the support means includes a lever member, one end of which is pivotally mounted on fulcrum means secured to the underside of the ash chamber, extending under and supporting the push rod member, and the other end of which forms a handle for pivoting the lever member down or up to raise or lower, respectively, the push rod member, the lever member being adjustably secured in any of several elevations by adjustment means.
There may be provided a barbecue grill additionally including an inverted cup member having a lip and a closed end, wherein a hole is cut in the center of the cooking grill and the lip of the inverted cup member is attached to the cooking grill surrounding the hole, and the push rod extends through the hole and into the inverted cup member and presses against its closed end to support and to raise and lower the inverted cup member and the cooking grill.
Another alternative is provided wherein the support means includes a vertical support member which is cylindrical and has external threads and upper and lower ends, and passes through a hole in the bottom the main chamber having corresponding internal threads, such that the internal threads engage the external threads, the upper end of said vertical support member being attached to the cooking grill, for rotating and for raising and lowering the cooking grill by rotating the lower end of the vertical support member. The lower end of the vertical support member may be fitted with a knob for gripping and rotating.
The elevation mechanism may be contained within the main chamber between the cooking grill and the fire source. In this instance, the fire source is a grate for supporting burning coals, additionally including an upstanding post member attached to the grate and extending upward perpendicular to the grate for supporting the cooking grill in its lowest position, and an inverted cup member having a lip and a closed end, wherein a hole is cut in the center of the cooking grill and the lip of the inverted cup member is attached to the cooking grill so that the lip surrounds the hole, and the upstanding post member extends through the hole and into the inverted cup member to guide the cooking grill when the elevation of the cooking grill is changed, and an elevation mechanism for raising and lowering the cooking grill.
The elevation mechanism includes a lever member located between the cooking grill and the grate, pivotally attached to the main chamber wall and extending essentially diametrically across the interior of the main chamber and through a port in the main chamber wall to form a handle end of the lever member, for changing the elevation of the cooking grill, a tubular member which surrounds the upstanding post member and extends between the lever member and the cooking grill, for transmitting the movements of the lever member to the cooking grill, and a ratchet and pawl assembly for maintaining the lever member and the cooking grill at more than one elevation.
The elevation means may also include a fulcrum member mounted on the grate or the ash chamber and extending upward toward the cooking grill, having an essentially vertical edge with at least two teeth cut into the edge having and a horizontally projecting fulcrum pin, and a lever member with an axial slot for slidably receiving the fulcrum pin, and a horizontally projecting securing pin which can slide between the teeth when the lever member is slid axially in one direction, and out from the between the teeth when the lever member is slid axially in the opposite direction, one end of the lever member being located adjacent the upstanding post and supporting the cooking grill, and the other end extending through a port in the main chamber wall and serving as a handle for pivoting the lever member and thereby changing the elevation of the cooking grill.
The elevation means may also include a fulcrum member mounted on the grate or the ash chamber and extending upward toward the cooking grill having a horizontally projecting fulcrum pin, and a lever member with a pin hole for receiving the fulcrum pin, one end of the lever member being located adjacent the upstanding post and supporting the cooking grill, and the other end extending through a port in the main chamber wall and serving as a handle for pivoting the lever member and thereby changing the elevation of the cooking grill, said other end having a ratchet vertically and pivotally suspended therefrom for engaging a fixed pawl attached to the ash chamber.
In accordance with still another feature, there is provided a barbecue grill including cooking grill support means disposed in the reversible top chamber for supporting the cooking grill in its reversed position.
In accordance with a still further feature, there is provided a barbecue grill wherein the reversible top chamber includes an upward facing projection for supporting the top chamber in its reversed position.
In addition, there may be provided a barbecue grill which has a plurality of upward facing legs circumferentially attached to the reversible top chamber for supporting the top chamber in its reversed position, wherein the main chamber and the ash chamber have peripheral walls, wherein the peripheral wall of the ash chamber is inwardly spaced from the peripheral wall of the main chamber for forming air access to the fire source.
Further still, there may be provided a barbecue grill which includes a plurality of legs and an equal plurality of leg holders attached to the underside of the ash chamber or peripherally attached to the peripheral wall of the main chamber for receiving those legs.
BRIEF DESCRIPTION OF THE DRAWINGS
Various other objects, advantages, and features of the invention will become apparent to those skilled in the art from the following discussion taken in conjunction with the following drawings, in which:
1. FIG. 1 is an elevational cross-sectional view of the first embodiment of the invention, showing the interior construction. The optional features of peripherally attached legs and a non-integral ash chamber are as illustrated in FIGS. 1 through 10;
2. FIG. 2 is a plan view of the invention with part of the wall broken away to show the interior construction;
3. FIG. 3 is an elevational view of the invention showing the reversible top chamber in reversed position;
4. FIG. 4 is a fragmentary detail view showing a bracket for supporting the cooking grill;
5. FIG. 5 is an elevational view of the invention showing external details of the invention assembled for storage;
6. FIG. 6 is an elevational fragmentary enlarged detail of the invention showing a latching detail for the top chamber;
7. FIG. 7 is a top plan view of the invention showing the legs inserted in resilient leg holders for storage;
8. FIG. 8 is a fragmentary detail view of the invention showing the chambers in opened position;
9. FIG. 9 is an elevational view of the invention showing the chambers in opened position;
10. FIG. 10 is a fragmentary enlarged detail view showing holding details, seen along the line 10--10 of FIG. 9;
11. FIG. 11 is a side cross-sectional view of the invention showing the interior construction of the elevation assembly wherein an end of the lever member supports the push rod. This and subsequent FIGURES illustrate the preferred leg and leg holder attachment positions at the underside of the ash chamber, and the preferred ash chamber design which is integral with the main chamber;
12. FIG. 12 is a side cross-sectional view of the invention showing the interior construction of the elevation assembly wherein an end of the lever member supports the push rod, and the cooking grill includes the inverted cup member feature;
13. FIG. 13 is a fragmentary detail view of the lever member adjustment assembly.
14. FIG. 14 is a side cross-sectional view of the invention showing the interior construction of the elevation assembly wherein the middle of the lever member supports the push rod; and
15. FIG. 15 is a side cross-sectional view of the invention showing the interior construction of the elevation assembly wherein the push rod is threaded and engages threads in a hole in the ash chamber.
16. FIG. 16 is a side cross-sectional view of the invention showing the interior construction of the elevation assembly wherein the lever member extends radially from the center of the main chamber between the cooking grill and the grate through a port in the main chamber wall and pivots on a fulcrum mounted on the grate.
17. FIG. 17 is a close-up view of a preferred ratchet construction for securing the lever member and grill at any of several elevations, wherein the ratchet is pivotally suspended from the handle end of the lever member and engages a fixed pawl attached to the ash chamber.
18. FIG. 18 is a side cross-sectional view as in FIG. 16 wherein the lever member is pivotally attached to the main chamber wall and extends diametrically through the main chamber.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention which may be embodied in various forms. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for the claims and as a representative basis for teaching one skilled in the art to variously employ the present invention in virtually any appropriately detailed structure.
Reference is now made to the drawings, wherein like characteristics and features of the present invention shown in the various FIGURES are designated by the same reference numerals.
FIRST PREFERRED EMBODIMENT
Referring to FIGS. 1, 2, 3, 5, 7 and 8 a main chamber 1, advantageously of circular construction, with a peripheral wall 2 which contains a cooking grill 3 on which foodstuffs to be grilled or cooked can be placed, is shown. Below the cooking grill 3 there is a fire source, e.g. in the form of a slotted grate 4 which can hold a fire source, such as coal briquets 6, wood chips, charcoal or other combustible materials. A divider 10 in the form of a low vertical wall is positioned atop the grate 4 dividing the surface of the grate into two or more sections that each, several or all can be used to support burning material. The drawing shows the grate divided into two sections of which, for example, the left hand section may be covered with burning coals, as shown. The user of the barbecue grill can selectively heat the food-stuffs placed on the cooking grill 3 by turning it by means of a handle having a vertical elongate member 8 resting with its lower end 9 on the upper end 11 of an upstanding post 12 rigidly attached to the grate 4. By intermittently turning the handle, the user can accomplish intermittent cooking in which the food goes back and forth over the coals until it is properly cooked.
The post 12 leads loosely through an opening 13 in the grate 3 which is suspended by at least two downward facing rods 14, each attached at its upper end to a transverse support bracket 16, with a threaded hole 17 through which the elongate member 8 is threaded. The suspended grate 3 can rotate about the post 12, and its height above the grate 3 ca be adjusted by turning the knob 7 with the threaded member 8 in the threaded hole 17.
The fire source 4 can alternatively be a gas burner (not shown) with several gas jets as is well known, wherein various jets or groups of jets can be supplied with cooking gas through separate gas valves so that the heating surface can be sectionalized in a manner similar to the divided grate sections described above.
An ash chamber 18 to catch ashes and embers from the burning coals 6 is preferably a horizontal bottom wall integrally joined with main chamber walls 2. Alternatively, ash chamber 18 is a disk-shaped pan with upstanding peripheral walls 19 placed below the grate 4 and having its walls 19 spaced inward from the main chamber walls 2 to form a space indicated by arrows 21 for admitting air to the fire source 4. This alternative variation of ash chamber 18 is attached by rivets 22, screws or the like to the peripheral walls 2 of the main chamber 1. FIGS. 1 through 10 illustrate the invention with the alternative ash chamber 18 design, while FIGS. 11 through 17 illustrate the preferred ash chamber 18 design.
A plurality of legs 23 are slidably inserted in leg holders 24. After use, the legs 23 can be drawn out of the holders 24, and stored in resilient snap-in leg holders 26, best seen in FIGS. 7 and 8. Holders 24 may be attached to the periphery of chamber walls 2, as illustrated in FIGS. 1 through 10, or attached to the underside of ash chamber 18, as illustrated in FIGS. 11 through 17.
Carrying handles 27 may advantageously be attached to the main chamber walls 2.
An upper top chamber 5 with lower rolled edges 28 that fit over the peripheral walls 2 of the main chamber 1 serves two purposes, namely that of a cover for the main chamber 1, as shown in FIGS. 1 and 2, and that of supporting the cooking grill 3 in its inverted (upside-down) position, as shown in FIG. 3, for serving the cooked foodstuffs after completion of cooking. To that end a plurality of small inward facing brackets 29 are disposed peripherally along the peripheral wall 31 of the top chamber 5, attached to the peripheral walls 31. The top chamber 5 has an upward facing projection 32, that in its normal position, as seen in FIG. 1, makes room for the handle 7 and support bracket 16, and in its inverted position, seen in FIG. 3, serves to catch drippings and gravy from the grilled foodstuffs, after the cooking grill has been removed from the main chamber and placed on the brackets 29 of the upturned top chamber 5, as seen in FIG. 3.
The top chamber 5 may advantageously have short legs 33 as seen in FIGS. 1 and 3 that serve to steady the top chamber in its reversed position, for example on top of a table (not shown). Alternatively the projection 32 may have small dimples 35, as seen in FIG. 3 for steadying the top chamber in the reversed position.
FIG. 4 shows the brackets 29 as seen along the line 4--4 of FIG. 3.
FIGS. 5 and 6 show the top chamber 5 secured to the main chamber 1 in assembled position, e.g. for storage, by means of a slot 34 and lip 36 attachment and a rivet 37.
FIG. 9 shows the top chamber 5 and ash chamber 18 pivotally attached by means of respective hinges 38, 39 to the walls 2 of the main chamber 1 as may be required to control airflow to the heat source in the main chamber. Respective holding brackets 41, 42, with adjusting holes 43 are advantageously provided to respectively hold the top or bottom chamber in a selected position.
SECOND PREFERRED EMBODIMENT
The second preferred embodiment is like the first, except that threaded member 8, upstanding post 12, rods 14 and bracket 16 are replaced with an elevation assembly 50. Assembly 50 raises and lowers the cooking grill 3 and is operated from underneath the ash chamber 18. Assembly 50 may take any of several forms, which include the following.
A tubular member 52 is attached to the center of grate 4 and extends perpendicularly upward. See FIG. 11. A push rod 54 extends axially through member 52, through grate 4, and through a hole 60 in the center of ash chamber 18. The top end 56 of push rod 54 bears against cooking grill 3, so that moving push rod 54 upward within member 52 raises cooking grill 3. Conversely, moving push rod 54 downward lowers cooking grill 3. The lowest position of cooking grill 3 is reached when cooking grill 3 rests on tubular member 52. Cooking grill 3 may include a solid center plate 62 for push rod 54 to bear against. Rather than simply bearing against cooking grill 3, push rod 54 may alternatively be attached thereto.
Alternatively, the center of cooking grill 3 may be cut away to form a port 64 surrounded by the lip 66 of an inverted cup member 70, which is attached to cooking grill 3. See FIG. 12. In this instance, push rod 54 is of sufficient length to extend through port 64 into cup member 70, so that top end 56 bears against closed end 72. When cooking grill 3 is in its lowest position, closed end 72 rests on tubular member 52. Rather than simply bearing against closed end 72, push rod 54 may alternatively be attached thereto.
Push rod 54 is moved upward and downward within tubular member 52 by an adjustable support apparatus 80. Apparatus 80 includes a lever member 82 having a support end 84 and a handle end 86. Lever member 82 is mounted on a fulcrum 90 attached to the underside 92 of ash chamber 18. Push rod 54 rests on the support end 84 of lever member 82. An adjustment device 100, such as a screw 102 extending through a threaded passageway 104 in lever member 82 and against underside 92, holds handle end 86 in one of many possible positions, in turn holding push rod 54 at one of many elevations. See FIG. 13. Push rod 54 is not attached to lever member 82, so that push rod 54 remains free to rotate, which in turn assures that cooking grill 3 is free to rotate.
Fulcrum 90 may alternatively be attached to the edge of the underside 92 of ash chamber 18. The end of lever member 82 which was support end 84 in the above described arrangement is pivotally joined to fulcrum 90. Lever member 82 extends diametrically across the underside 92 from fulcrum 90 to handle end 86. In this instance, the middle 106 of lever member 82 supports push rod 54. See FIG. 14. Again, push rod 54 is not attached to lever member 82.
The lower portion 108 of push rod 54 may alternatively be threaded and engage corresponding threads in hole 60. This permits the raising and lowering of push rod 54, and thus of cooking grill 3, simply by rotating push rod 54 in one direction or the other. See FIG. 15. A knob 110 is preferably affixed to the lower end 112 of push rod 54 for the user to grip while turning push rod 54.
Hole 60 and its internal threads may be extended for added strength by attaching a plate 114 with a threaded bore 116 over hole 60. Bore 116 is of the same diameter as hole 60 and they are aligned one above the other with a common center axis.
THIRD PREFERRED EMBODIMENT
The third preferred embodiment is similar to the second. The elevation assembly 50 is contained within the main chamber 1 between the cooking grill 3 and the grate 4. See FIGS. 16 and 17. Assembly 50 is operated by moving the handle end 86 of lever member 82, which extends through a vertical slot 122 in main chamber wall 2.
The cooking grill 3 is fitted with the cup member 70. Upstanding post 12, as described for the first embodiment, extends from grate 4 into cup member 70. When the cooking grill 3 is in its lowest position, the closed end 72 of cup member 70 rests on the top end 124 of upstanding post 12. Lever member 82 bears against the cooking grill 3, adjacent to cup member 70, to raise, lower and support cooking grill 3. Cup member 70 may be provided with a flange portion 126 extending from lip 66 underneath cooking grill 3, to provide a solid surface for lever member 82 to bear against.
Lever member 82 can be mounted in at least two ways, each having its own particular adjustment and support mechanism 130. The first way, illustrated in FIG. 16, is for lever member 82 to extend only to the middle of cooking grill 3, terminating to form support end 84. Support end 84 may take the form of a fork of ring surrounding upstanding post 12, or a slat extending adjacent to or through upstanding post 12. Lever arm 82 pivots on a fulcrum pin 132 projecting from a fulcrum member 134. Fulcrum member 134 is a plate mounted vertically along a radial line between upstanding post 12 and wall 2, and attached to ash chamber 18. The vertical edge 136 of fulcrum member 134 closest to wall 2 is cut into a radial arc with its center at pin 132. Edge 136 is notched to form gear teeth 140. Fulcrum pin 132 extends through an axial slot 142 in lever member 82, which permits lever member 82 to slide longitudinally beside fulcrum member 134 over fulcrum pin 132. A positioning pin 144 projects from lever member 82. When lever member 82 is slid toward upstanding post 12, positioning pin 144 slides between two of the gear teeth 140. Teeth 140 may alternatively extend from the exterior of wall 2, adjacent vertical slot 122, with positioning pin 144 once again located to slide between teeth 140.
To adjust the height of cooking grill 3, lever member 82 is slid longitudinally away from upstanding post 12. This action causes positioning pin 144 to slide out from between gear teeth 140, freeing lever member 82 to pivot about fulcrum pin 132. Lever member 82 is pivoted to raise or lower cooking grill 3 to the desired elevation. Then lever member 82 is slid toward upstanding post 12 to place positioning pin 144 between two of the adjacent gear teeth 140. This holds lever member 82 and cooking grill 3 in the desired position until further repositioning is sought. The coal briquets 6 is preferably confined to the side of grate 4 opposite mechanism 130.
Alternatively, fulcrum member 134 may be mounted on grate 4 or ash chamber 18 and extend upward toward cooking grill 3, having a horizontally projecting fulcrum pin 132 fitting through a pin hole 142 in lever member 82. A ratchet 148 is vertically and pivotally suspended from handle end 86 for engaging a fixed pawl 160 attached to ash chamber 18 or main chamber 1. See FIG. 17.
The other illustrated variation of this embodiment is like the first, except that lever member 82 extends diametrically across the interior of main chamber 1 and is pivotally attached to wall 2 opposite handle end 86. See FIG. 18. Lever member 82 is contained within separating wall 10, which for this variation is a double wall. A tube 150 slidably surrounds upstanding post 12 and extends from the middle 106 of lever member 82 to flange portion 126. Cooking grill 3 is supported by flange portion 126, which rests on tube 150, which in turn rests on the middle 106 of lever member 82. Handle end 86 is bent upward at a right angle to form a connector portion 152, and then turns at another right angle to again extend in its original direction away from upstanding post 12. The remote edge 154 of connector portion 152 is cut to form ratchet teeth 156, which slope only in the downward direction, and are engaged by a pawl 160. Pawl 160 is resiliently retained against remote edge 154 by a spring 158.
To adjust the height of cooking grill 3, handle end 86 is lifted to raise the cooking grill 3. The slope of ratchet teeth 156 permits the pawl 160 to slide over them when the handle end 86 is raised. When the desired elevation of cooking grill 3 is reached, handle end 86 is simply released. Spring 158 causes pawl 160 to automatically engage teeth 156 and prevent downward movement. To lower cooking grill 3, the pawl 160 is pulled out from between ratchet teeth 156, and handle end 86 is lowered until cooking grill 3 reaches the desired elevation. Then the pawl 160 is released to again engage ratchet teeth 156 and retain cooking grill 3 at this elevation. The pivoting, suspended ratchet and pawl assembly set forth earlier may alternatively secure handle end 86.
The low profiles of the elevation assemblies of the second and third embodiments illustrated in FIGS. 11 and 13-15 permit the use of the beveled lid shown in those FIGURES. The beveled portion fits against the rim of the main chamber 1 when top chamber 5 is inverted, eliminating the need for top chamber 5 short legs 33.
The grill of the invention can be used in two modes:
Half-a-grill mode: In this mode only half of the grate is filled with charcoal, this becoming the "fire-side" with the other half becoming the "indirect heat side". The "indirect heat side" achieves four functions:
a) Intermittent exposure cooking: The free-spinning grid with the food on it can be rotated back and forth over the "fire side" (for direct exposure to the fire) and the "indirect heat side" (for continuity of cooking at lower heat). The food can be brought back to the "fire side" for a final roasting of the surface of the food. In most grills this is not possible as the surface of the food is being roasted and burned while the center is still raw.
b) Defrosting: The food is left over the "indirect heat side" to accomplish defrosting.
c) Keep warm: The "indirect heat side" allows the food to be kept warm until it is ready to be served.
d) Verification of degree of cooking: A piece of food can be cut to determine to what extent it has been cooked inside, and this can be done without exposing the hands to the fire. When cooking on the "indirect side", the hands are farther away from the fire. When cooking on the "fire side", in case of a flame-up, the food can be rotated away from the fire to the "indirect heat side".
Full-grill mode: Both halves of the grate can be loaded with charcoal if desired, for example to cook a large amount of food, while still retaining the advantages of the rotating grid and vertical adjustment of the grid.
This novel, economical way of barbecuing using Intermittent Exposure Cooking greatly reduces or eliminates the roast-burn biproduction of toxic, dangerous substances and allows direct and indirect cooking and defrost-keep warm capabilities.
While the invention has been described, disclosed, illustrated and shown in various terms or certain embodiments or modifications which it has assumed in practice, the scope of the invention is not intended to be, nor should it be deemed to be, limited thereby and such other modifications or embodiments as may be suggested by the teachings herein are particularly reserved especially as they fall within the breadth and scope of the claims here appended. | A multi-chambered barbecue grill having a main chamber, a cooking grill located in the main chamber, a fire source located in the main chamber below the cooking grill, an ash chamber attached to the main chamber below the fire source for catching ashes, and a reversible top chamber located above the main chamber, adapted for receiving the cooking grill in its reversed position. Various mechanisms are provided for raising and lowering the cooking grill to desired elevations above the fire source. | 31,291 |
This is a division of application Ser. No. 08/627,281 filed Apr. 4, 1996, now U.S. Pat. No. 6,305,069.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an oxide superconducting wire and a method of preparing the same, and a cable conductor which is formed by assembling such oxide superconducting wires, and more particularly, it relates to an oxide superconducting wire which can carry a heavy current in ac application and a method of preparing the same, and a cable conductor which is formed by assembling such oxide superconducting wires.
2. Description of the Background Art
The principal feature of an oxide superconductor resides in that the same is in a superconducting state also at a temperature exceeding the liquid nitrogen temperature. Therefore, a wire consisting of such an oxide superconductor is expected for application to a superconducting device, as a material which can be used under cooling with liquid nitrogen.
The inventors have developed a tape-shaped Bi-based Ag-coated multifilamentary wire, which is prepared from filaments of an oxide superconductor with a stabilizer of silver. A Bi-based Ag-coated wire can be prepared by charging a metal pipe with raw material powder serving as a precursor for a Bi oxide superconductor, wire-drawing the pipe and thereafter repeating rolling and a heat treatment a plurality of times.
On the other hand, a multifilamentary wire can be prepared by charging metal pipes with raw material powder, wire-drawing the same, engaging a plurality of such wires in a metal pipe for forming a multi-filamentary substance, further wire-drawing the same and thereafter repeating rolling and a heat treatment a plurality of times.
Among such preparation steps, the rolling step is effective for improving the orientation of crystal grains in the Bi superconductor having a plate-type crystal structure, strengthening bonding between the crystal grains and improving the density of the filaments, and regarded as being indispensable for attaining a high critical current density in preparation of a Bi-based Ag-coated wire.
Further, the aspect ratio of a section of the wire is increased by this rolling, whereby the aspect ratio of a section of each filament is also increased. This is advantageous for growth of the plate-type crystals, and a high critical current density is consequently attained.
On the other hand, the heat treatment step for the purpose of sintering is also indispensable for forming the superconductor, attaining crystal growth and strengthening bonding between the crystal grains, since the oxide superconductor is ceramics.
The Bi-based Ag-coated wire which is prepared in the aforementioned manner is excellent in bending property and capable of preparing a long wire having a critical current density exceeding 10 4 A/cm 2 , and hence the same is expected for application to a superconducting cable or magnet.
In ac application of such an oxide superconducting wire, however, ac loss resulting from a fluctuating magnetic field in driving comes into question. In a cable conductor which is formed by assembling superconducting wires, on the other hand, there arises a new problem to be solved such as a drift phenomenon resulting from ununiformity between impedances of the wires, which cannot be caused in dc application. Due to a drift caused in such a manner, further, loss upon formation of the conductor is disadvantageously increased beyond the sum of ac loss values of strands.
As to such problems caused in ac application, various countermeasures have generally been studied in relation to metal superconducting wires, for example. In more concrete terms, countermeasures of arranging high resistance barrier layers around or between filaments, preparing an extra-fine multifilamentary wire from superconducting filaments, increasing the specific resistance of a matrix and the like are studied in order to reduce ac loss. In order to suppress a current drift by uniformalizing the impedances of the filaments or wires in a conductor for an ac magnet, on the other hand, countermeasures of twisting the filaments or wires, dislocating the wires or filaments and the like are studied.
In order to attain a heavy current, further, a countermeasure of further twisting primary stranded wires each prepared by twisting superconducting strands to attain a flat-molded multinary structure or the like is studied.
While a countermeasure of further twisting primarily stranded wires to attain a multinary structure or the like must be taken also in employment of the aforementioned Bi-based Ag-coated wire for ac application similarly to the metal superconducting wire, however, it is impossible to implement the aforementioned multinary structure through an oxide superconducting wire by a method which is absolutely identical to that for the metal superconducting wire. This is because a Bi-based Ag-coated multifilamentary wire indispensably requires rolling and sintering processes as described above, while no such rolling and sintering steps are required for preparing a metal superconducting wire.
Namely, it is difficult to twist wires of a Bi oxide superconductor after sintering, since the Bi oxide superconductor is ceramics which is weak against bending distortion. Even if such wires can be twisted, a high critical current density cannot be attained. Further, it is difficult to twist wires in which aspect ratios of sections are increased by rolling. Even if such wires can be twisted, a number of clearances are defined in the stranded wire as compared with that prepared by twisting round wires, and a high critical current density cannot be attained.
SUMMARY OF THE INVENTION
In order to solve the aforementioned problems, an object of the present invention is to provide an oxide superconducting wire which maintains a high critical current density and has a small current drift with small ac loss when the same carries an alternating current and a method of preparing the same, and a cable conductor which is formed by assembling such oxide superconducting wires.
According to an aspect of the present invention, an oxide superconducting wire is provided. This oxide superconducting wire is a flat-molded stranded wire which is formed by twisting a plurality of metal-coated strands consisting of an oxide superconductor, and is characterized in that the flat-molded stranded wire has a rectangular sectional shape, and a section of each strand forming the flat-molded stranded wire has an aspect ratio of at least 2.
Throughout the specification, the term “aspect ratio” indicates the ratio of the thickness to the width in a cross section of the oxide superconducting wire.
Superconducting filaments provided in the strands can be brought into flat shapes having a high aspect ratio by setting the strands at an aspect ratio of at least 2. Consequently, a superconducting wire having a high critical current density can be obtained. In particular, the aspect ratio of the superconducting filaments is preferably around 10. The section of each strand preferably has an aspect ratio of not more than 20. It is difficult to increase the aspect ratio of the strands beyond 20 in case of twisting and molding the same.
According to the present invention, the strands are completely dislocated due to the twisting, whereby the impedances of the strands forming the stranded wire can be equalized to each other.
According to the present invention, further, the stranded wire has a rectangular sectional shape. Thus, the wire can be densely wound to be advantageously compacted when the same is applied to a coil or a cable.
Preferably, the metal coatings of the strands consist of silver or a silver alloy, and coating layers consisting of a material having higher resistance than silver are provided on the outer peripheries of the metal coatings.
Due to the presence of such coating layers, the strands can be prevented from bonding in the stranded wire, so that ac loss is effectively reduced.
The material having higher resistance than silver is prepared from a high resistance metal material or an inorganic insulating material, for example.
When no such coating layers consisting of a material having higher resistance than silver such as a high resistance metal material or an inorganic insulating material are present, metal matrices of silver or the like are so diffused during the heat treatment that the strands are disadvantageously bonded with each other, and hence bonding loss between the strands may be increased. The coating layers having higher resistance than silver effectively function to reduce such bonding loss.
The high resistance material is prepared from an Ag—Mn alloy, an Ag—Au alloy, or Ni or Cr having high resistance, for example.
On the other hand, the inorganic insulating material is prepared from an oxide insulating material such as MgO or CuO which is obtained by oxidizing Mg or Cu, for example. Bonding between the strands can be completely prevented by the coating layers consisting of such an insulating material. Further, the effect of dislocation is rendered further complete.
According to another aspect of the present invention, a method of preparing an oxide superconducting wire is provided. This method comprises the steps of preparing a stranded wire by twisting a plurality of strands each formed by metal-coating an oxide superconductor or raw material powder therefor, flat-molding the prepared stranded wire, and repeating rolling and a heat treatment of at least 800° C. on the flat-molded stranded wire a plurality of times.
Namely, a plurality of round wire type strands each formed by metal-coating an oxide superconductor or raw material powder therefor, which are not sintered as wires, are prepared. Then, the plurality of strands are twisted for preparing a stranded wire. As to the number of twisted strands, three, seven or twelve strands can be twisted, for example.
This stranded wire is flat-molded and thereafter further rolled, whereby superconducting filaments having circular sections which are provided in the strands can be deformed in the form of flat plates having a high aspect ratio. The dimensions of the superconducting filaments are preferably within the ranges of 0.1 to 100 μm in thickness and 1 μm to 1 mm in width. In the flat-molding, the superconducting filaments can be simultaneously deformed by application of rolling loads from above and under the wire.
Thereafter the step of performing rolling and a heat treatment is carried out at least twice, whereby an oxide superconducting wire in which strands are completely dislocated in order to cope with application to an ac wire can be obtained.
According to the present invention, the respective filaments are subjected to twisting as well as rolling. In the inventive wire, therefore, the impedances of the respective filaments are uniformalized by twisting. Also when the wire carries an alternating current, therefore, the current can be uniformly fed to the respective filaments. Further, bonding currents between the filaments are suppressed for effectively reducing ac loss. When the surfaces of the strands are insulated, it is possible to further suppress the bonding currents and reduce the ac loss.
According to the present invention, the flat-molded stranded wire rolled and heat treated. Thus, a high critical current density can also be attained by strengthening grain bonding which is broken by distortion in formation of the stranded wire and regularizing disturbed orientation.
According to the present invention, further, it is also possible to prepare a flat-molded multinary stranded wire by further twisting a plurality of primary stranded wires each obtained by twisting a plurality of strands. As to the number of twisted stranded wires, nine primary stranded wires can be twisted, for example.
It is particularly important to carry out the twisting step a plurality of times, in order to attain the aforementioned effects when the number of strands which are twisted for the purpose of attaining a high capacitance is increased.
According to the present invention, further, a stranded wire may be prepared by stacking and integrating a plurality of tape-shaped strands with each other and thereafter twisting the same. Particularly in case of a silver sheath Bi 2223 superconducting wire, it is important to prepare tape-shaped strands for attaining a high critical current density. Twisting is simplified by stacking the tape-shaped strands with each other for reducing the aspect ratio of sections thereof and thereafter twisting the same, and characteristic deterioration caused by bending distortion or the like can be effectively prevented.
The strands can be integrated with each other by a method of heat treating the stacked strands and bonding the same with each other by diffusion of silver, a method of performing compression molding, or a method of stacking the strands in a flat pipe, for example. In case of a long wire, it is effective to wire-draw and twist the strands after integrating the same with each other.
The tape-shaped strands are preferably previously heat treated in advance of twisting. It is possible to reinforce grain bonding of the oxide superconductor for attaining a high critical current density by further performing a heat treatment after forming the oxide superconductor by this heat treatment and performing the step of twisting etc.
According to the present invention, the method preferably further comprises a step of previously coating the outer peripheries of the strands with a material having higher resistance than silver before twisting the metal-coated strands for preparing the stranded wire.
The coating layers consisting of a material having higher resistance than silver can be formed by a method of adding Ni or Cr of high resistance to the outer surfaces of the strands by plating, or a method of applying a solution in which powder of an oxide insulating material such as AlO 3 is dispersed to the outer surfaces of the strands, for example.
Alternatively, coating layers consisting of a metal such as Mg or Cu may be formed on the outer peripheries of the strands so that these layers are thereafter oxidized to form coating layers consisting of an oxide insulating material such as MgO or CuO. In particular, excellent workability can be attained by performing an oxidizing step after the rolling of the stranded wire. Mg or Cu is richer in workability than MgO or CuO, and hence the stranded wire can be molded and rolled into a better shape by oxidizing the coating layers after performing twisting and rolling.
According to the present invention, the method preferably further comprises a step of previously coating the flat-molded stranded wire with a metal before rolling.
If the outermost layer of a flat-molded multinary stranded wire is so thin that superconducting filaments may be exposed through the subsequent rolling step, the stranded wire is preferably coated with a metal in advance.
Metal coating layers may be further formed on the outer peripheries of the strands which are coated with a metal such as silver or a silver alloy by performing metal coating on the surface of the flat-molded multinary stranded wire or engagement in a flat metal pipe.
According to the present invention, further, each strand is preferably a multifilamentary wire which is formed by embedding a plurality of superconductors in a metal matrix. Due to a plurality of superconducting filaments provided in each strand, flexibility of the wire is improved.
According to the present invention, the strands themselves are preferably subjected to twisting. Due to such twisting of the strands themselves, bonding loss and eddy current loss are reduced thereby reducing ac loss as a result.
According to the present invention, the method preferably further comprises a step of temporarily heat treating the flat-molded stranded wire before rolling. Workability in rolling can be improved by heat treating the flat-molded stranded wire at about 800° C. for diffusion-bonding the strands with each other.
According to the present invention, further, a step of winding strands around a core of a flat-molded stranded wire and flat-molding the same is preferably repeated a plurality of times.
A wire having low loss and a high capacitance can be obtained by repeating flat-twisting/molding a plurality of times. Such a wire is effective as a material for forming a compact cable conductor having low loss and a high capacitance.
According to still another aspect of the present invention, an oxide superconducting cable conductor is provided. This oxide superconducting cable conductor is formed by assembling oxide superconducting wires on a cylindrical former. Each oxide superconducting wire is a flat-molded stranded wire which is formed by twisting a plurality of metal-coated strands consisting of an oxide superconductor. This flat-molded stranded wire has a rectangular sectional shape, while a section of each strand forming the flat-molded stranded wire has an aspect ratio of at least 2.
In a single-layer cable conductor formed by assembling oxide superconducting wires on a former in a single layer, for example, all strands are dislocated to occupy positions which are electromagnetically completely equivalent to each other, whereby current distribution in the conductor is so uniformalized that increase of ac loss caused by a drift can be prevented. When wires are spirally wound on a former, on the other hand, it is effective to form the conductor in a two-layer structure so that first and second layers are wound in opposite directions, in order to cancel a magnetic field component along the longitudinal direction of the conductor. Thus, a drift between the layers caused by impedance difference therebetween as well as following ac loss can be minimized as compared with a multilayer conductor, by forming the conductor in a single- or two-layer structure.
According to the present invention, as hereinabove described, a metal-coated oxide superconducting wire having a high critical current density which can transmit a current with los loss can be obtained.
According to the present invention, further, it is also possible to increase the critical current per wire beyond 100 A by increasing the number of stranded wires and the degree of twisting, i.e., the number of times of twisting, so that the inventive wire is usefully applied to an oxide superconducting cable or a superconducting magnet which is employed for carrying a high capacitance alternating current.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a sectional view showing an intermediate in a step of preparing an oxide superconducting wire according to Example 1 of the present invention;
FIG. 2 is a sectional view showing the structure of the oxide superconducting wire according to Example 1 of the present invention;
FIG. 3 is a sectional view showing an intermediate in a step of preparing an oxide superconducting wire according to Example 5 of the present invention;
FIG. 4 is a sectional view showing an intermediate in another step of preparing an oxide superconducting wire according to Example 5 of the present invention;
FIG. 5 is a sectional view showing the structure of another exemplary oxide superconducting wire according to Example 5 of the present invention;
FIG. 6 is a sectional view showing the structure of a strand forming an oxide superconducting wire according to Example 6 of the present invention;
FIG. 7 is a sectional view showing the structure of a strand employed for an oxide superconducting wire according to Example 7 of the present invention;
FIG. 8 is a sectional view showing an intermediate in a step of preparing an oxide superconducting wire according to Example 7 of the present invention;
FIG. 9 is a sectional view showing an intermediate in another step of preparing an oxide superconducting wire according to Example 7 of the present invention;
FIG. 10 is a sectional view showing the structure of the oxide superconducting wire according to Example 7 of the present invention;
FIG. 11 is a sectional view showing an intermediate in a step of preparing an oxide superconducting wire according to Example 8 of the present invention;
FIG. 12 is a sectional view showing the structure of the oxide superconducting wire according to Example 8 of the present invention;
FIG. 13 is a perspective view showing the structure of an oxide superconducting cable conductor according to Example 12 of the present invention;
FIG. 14 is a sectional view showing the structure of the oxide superconducting cable conductor according to Example 12 of the present invention; and
FIG. 15 is a sectional view showing the structure of an oxide superconducting wire according to Example 13 of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
EXAMPLE 1
Bi 2 O 3 , PbO, SrCO 3 , CaCO 3 and CuO were blended with each other so that Bi, Pb, Sr, Ca and Cu were in composition ratios of 1.81:0.30:1.92:2.01:3.03. The blended powder was heat treated a plurality of times. This powder was crushed after each heat treatment. The powder obtained through such a heat treatment and crushing was further crushed by a ball mill, to obtain submicron powder.
Precursor powder obtained in the aforementioned manner was heat treated at 800° C. for 2 hours, and thereafter charged in a silver pipe of 12 mm in outer diameter and 8 mm in inner diameter. Then, the silver pipe charged with the powder was drawn into 0.9 mm, to prepare strands. Seven such strands were twisted to prepare the so-called primary stranded wire. Further, 15 such primary stranded wires were twisted and thereafter compression-molded, for preparing a flat-molded secondary stranded wire.
FIG. 1 is a sectional view showing the structure of the secondary stranded wire prepared in the aforementioned manner. Referring to FIG. 1, 15 primary stranded wires 12 each formed by twisting seven strands 11 are further twisted.
Then, the secondary stranded wire was heat treated at 800° C. for 2 hours so that the strands were integrated with each other by diffusion bonding, and thereafter rolled. Then, the stranded wire was heat treated at 845° C. for 50 hours, further rolled and thereafter heat treated at 840° C. for 50 hours.
FIG. 2 is a sectional view showing the structure of an oxide superconducting wire obtained in the aforementioned manner. Referring to FIG. 2, the flat-molded stranded wire has a rectangular sectional shape in this wire, and each strand 11 has a flat section having an aspect ratio (W1/T1) of about 4.
Then, the oxide superconducting wire obtained in the aforementioned manner was subjected to measurement of a critical current value Ic in liquid nitrogen. Consequently, this wire exhibited a value Ic of 50 A.
Ac loss values of a multilayer conductor which was formed by stacking five Bi-based Ag-coated single-filamentary wires having a critical current value Ic of 10 A and the inventive wire were measured by an energization four-probe method. Consequently, it has been confirmed that the ac loss of the inventive wire was smaller than that of the multilayer conductor in a region of not more than 50 Ap.
EXAMPLE 2
Precursor powder having a composition equal to that of the precursor powder employed in Example 1, which was obtained similarly to Example 1, was heat treated at 800° C. for 2 hours, and thereafter charged in a silver pipe of 12 mm in outer diameter and 9 mm in inner diameter. Then, the silver pipe charged with the powder was drawn into 0.9 mm, to prepare strands. Seven such strands were twisted to form the so-called primary stranded wire. Further, 15 such primary stranded wires were twisted and thereafter compression-molded, to prepare a flat-molded secondary stranded wire.
Then, the secondary stranded wire was engaged in a flat silver pipe of 1 mm in thickness, subjected to diffusion bonding at 800° C. for 2 hours, and thereafter rolled. Then, the pipe was heat treated at 845° C. for 50 hours, further rolled and thereafter heat treated at 840° C. for 50 hours.
In the structure of an oxide superconducting wire obtained in the aforementioned manner, the flat-molded stranded wire had a rectangular sectional shape, and each strand had a flat section having an aspect ratio of about 4, similarly to Example 1.
Then, the oxide superconducting wire obtained in the aforementioned manner was subjected to measurement of a critical current value Ic in liquid nitrogen. Consequently, this wire exhibited a value Ic of 50 A.
Ac loss values of a multilayer conductor which was formed by stacking five Bi-based Ag-coated single-filamentary wires having a critical current value Ic of 10 A and the inventive wire were measured by an energization four-probe method. Consequently, it has been confirmed that the ac loss of the inventive wire was smaller than that of the multilayer conductor in a region of not more than 50 Ap.
EXAMPLE 3
Precursor powder having a composition equal to that of the precursor powder employed in Example 1, which was obtained similarly to Example 1, was heat treated at 800° C. for 2 hours, and thereafter charged in a silver pipe of 12 mm in outer diameter and 9 mm in inner diameter. Then, the silver pipe charged with the powder was drawn into 0.9 mm, and seven such wires were engaged in a silver pipe and drawn to prepare a seven-conductor multifilamentary wire. Further, the seven-conductor multifilamentary wire was twisted at a pitch of 20 mm. Seven strands consisting of such twisted seven-conductor multifilamentary wires were twisted, to prepare the so-called primary stranded wire. Further, 15 such primary stranded wires were twisted and thereafter compression-molded, to prepare a flat-molded secondary stranded wire.
Then, this secondary stranded wire was engaged in a flat silver pipe of 1 mm in thickness, subjected to diffusion bonding at 800° C. for 2 hours, and thereafter rolled. Then, the pipe was heat treated at 845° C. for 50 hours, further rolled and thereafter heat treated at 840° C. for 50 hours.
In the structure of an oxide superconducting wire obtained in the aforementioned manner, the flat-molded stranded wire had a rectangular sectional shape similarly to Example 1, and each strand had a flat section having an aspect ratio of about 5.
Then, the oxide superconducting wire obtained in the aforementioned manner was subjected to measurement of a critical current value Ic in liquid nitrogen. Consequently, the inventive wire exhibited a value Ic of 40 A.
Ac loss values of a multilayer conductor which was formed by stacking four Bi-based Ag-coated single-filamentary wires having a critical current value Ic of 10 A and the inventive wire were measured by an energization four-probe method. Consequently, it has been confirmed that the ac loss of the inventive wire was smaller than that of the multilayer conductor in a region of not more than 40 Ap.
EXAMPLE 4
Precursor powder having a composition equal to that of the precursor powder employed in Example 1, which was obtained similarly to Example 1, was heat treated at 800° C. for 2 hours, and thereafter charged in a silver pipe of 12 mm in outer diameter and 10 mm in inner diameter. Seven such silver pipes charged with the powder were drawn and further engaged in a silver pipe of 12 mm in outer diameter and 9 mm in inner diameter to form a seven-conductor wire, which in turn was drawn into 0.9 mm.
Seven strands consisting of seven-conductor wires obtained in the aforementioned manner were twisted to prepare the so-called primary stranded wire. Further, 15 such primary stranded wires were twisted and thereafter compression-molded, to prepare a flat-molded secondary stranded wire.
Then, this secondary stranded wire was engaged in a flat silver pipe of 1 mm in thickness, which in turn was rolled, heat treated at 845° C. for 50 hours, further rolled and thereafter heat treated at 840° C. for 50 hours.
In the structure of an oxide superconducting wire obtained in the aforementioned manner, the flat-molded stranded wire had a rectangular sectional shape similarly to Example 1, and each strand had a flat section having an aspect ratio of about 5.
Then, the oxide superconducting wire obtained in the aforementioned manner was subjected to measurement of a critical current value Ic in liquid nitrogen. Consequently, this wire exhibited a value Ic of 40 A.
Ac loss values of a multilayer conductor which was formed by stacking four Bi-based Ag-coated single-filamentary wires having a critical current value Ic of 10 A and the inventive wire were measured by an energization four-probe method. Consequently, it has been confirmed that the ac loss of the inventive wire was smaller than that of the multilayer conductor in a region of not more than 40 Ap.
EXAMPLE 5
Precursor powder having a composition equal to that of the precursor powder employed in Example 1, which was obtained similarly to Example 1, was heat treated at 800° C. for 2 hours, and thereafter charged in a silver pipe of 24 mm in outer diameter and 20 mm in inner diameter. Then, 61 such silver pipes charged with the powder were drawn into diameters of 1.02 mm and further engaged in a silver pipe of 24 mm in outer diameter and 20 mm in inner diameter, which in turn was further drawn into a diameter of 1.02 mm, to form a strand. 12 such strands were twisted and flat-molded.
FIG. 3 is a sectional view showing the structure of a flat-molded stranded wire 52 obtained in the aforementioned manner. Referring to FIG. 3, this stranded wire 52 had a width W2 of 7.4 mm, and a thickness T2 of 1.45 mm.
Then, this wire was rolled into a thickness of 1 mm, and thereafter heat treated at 845° C. for 50 hours. Then the wire was rolled into 0.9 mm, and thereafter heat treated at 840° C. for 50 hours.
FIG. 4 is a sectional view showing the structure of a reacted flat-molded stranded wire 58 according to the present invention obtained in the aforementioned manner.
Referring to FIG. 4, this stranded wire 58 had a width W2 of 12 mm, and a thickness T1 of 1 mm. Each strand 51 forming the stranded wire 58 had an aspect ratio (W1/T1) of 4.4. As a result of a detailed analysis, each superconducting filament provided in each strand 51 had a width of about 100 μm and a thickness of about 10 μm. The volume percentage of a Bi 2223 phase was about 95%. Further, this superconducting flat-molded stranded wire had a critical current value Ic of 110 A.
Throughout the specification, the term “volume percentage” indicates the ratio of a magnetization rate exhibited by each sample in practice with respect to a magnetization rate (−{fraction ( 1 / 4 )}π [emU/cc]) which is measured when a superconductor exhibits complete diamagnetism.
FIG. 5 is a sectional view showing the structure of another exemplary oxide superconducting wire 152 after rolling. The superconducting wire 152 having absolutely no clearances between strands 151 can be obtained by rolling the same under a condition of setting a draft at 30 to 40% while providing guides on both sides thereof.
As comparative example, a substance obtained by engaging 61 conductors and thereafter drawing the same into a diameter of 1.02 mm similarly to the aforementioned wire was rolled into a thickness of 0.25 mm, and heat treated at 845° C. for 50 hours to prepare a wire. Four such wires were stacked, rolled into a thickness of 0.9 mm and heat treated at 840° C. for 50 hours, to be subjected to measurement of a critical current value Ic. Consequently, this comparative example exhibited a value Ic of 100 A.
Further, ac loss values of the aforementioned two types of wires were measured by an energization four-probe method. Consequently, the ac loss of the flat stranded wire was 0.05 mW/m while that of comparative example was 0.5 mW/m in energization under 60 Hz and 20 A rms . Thus, it has been recognized that the ac loss was reduced to {fraction (1/10)} in the inventive wire.
EXAMPLE 6
Cr or Ni was plated on the surfaces of the strands prepared in Example 5. 12 such strands were twisted and flat-molded. After the molding, the stranded wire had a width of 7.4 mm and a thickness of 1.45 mm. This wire was rolled into a thickness of 1 mm, and thereafter heat treated at 845° C. for 50 hours. Thereafter the wire was rolled into 0.9 mm, and thereafter heat treated at 840° C. for 50 hours.
FIG. 6 is a sectional view showing the structure of each strand 61 forming the flat-molded stranded wire obtained in the aforementioned manner.
Referring to FIG. 6, this strand 61 had a flat shape at an aspect ratio (W1/T1) of 3.7, and comprised a coating layer 66 consisting of Cr or Ni plating on its outer periphery. Further, the strand 61 was formed by embedding 61 superconductor filaments 65 in a matrix 64 consisting of silver, and each filament 65 had a width W5 of about 90 μm and a thickness T5 of about 10 μm.
The arrangement of the filaments 65 shown in FIG. 6 is a mere example, and the present invention is not necessarily restricted to such arrangement.
The volume percentage of a Bi 2223 phase was about 95%, and the critical current value Ic was 105 A.
Ac loss of this wire which was measured by an energization four-probe method was 0.01 mW/m in energization under 20 A. Thus, it has been recognized that the ac loss was reduced to ⅕ as compared with the strand of Example 1.
EXAMPLE 7
Precursor powder having a composition equal to that of the precursor powder employed in Example 1, which was obtained similarly to Example 1, was charged in a silver pipe of 24 mm in outer diameter and 20 mm in inner diameter. 61 such silver pipes were drawn into diameters of 1.02 mm and engaged in an Ag—Mn alloy pipe of 24 mm in outer diameter and 20 mm in inner diameter, which in turn was drawn into a diameter of 1.02 mm. Thereafter this wire was twisted at a pitch of 25 mm and thereafter rolled into a width of 3 mm and a thickness of 0.25 mm, to prepare a tape-shaped strand.
FIG. 7 is a sectional view showing the structure of a tape-shaped strand 71 obtained in the aforementioned manner. Referring to FIG. 7, this strand 71 is formed by embedding 61 superconducting filaments 75 in a matrix 74 consisting of silver, and a coating layer 76 consisting of an Ag—Mn alloy is formed on its outer periphery.
Then, 12 tape-shaped strands 71 obtained in the aforementioned manner were stacked as shown in FIG. 8, and heat treated at 840° C. for 50 hours. Thus, a multilayer wire 77 obtained in this manner was flat-drawn so that each side was 1 mm, and thereafter four such wires were twisted and flat-molded as shown in FIG. 9 . In the molding, the thickness was reduced by 10%. This wire was heat treated at 840° C. for 50 hours.
FIG. 10 is a sectional view showing the structure of an oxide superconducting wire obtained in the aforementioned manner. Referring to FIG. 10, this wire is a flat-molded stranded wire formed by twisting four multilayer wires 77 .
Then, the oxide superconducting wire obtained in the aforementioned manner was subjected to measurement of a critical current value Ic in liquid nitrogen. Consequently, this wire exhibited a value Ic of 50 A.
In this oxide superconducting wire, each superconducting filament had a width of about 30 μm and a thickness of about 3 μm.
Further, ac loss values of the flat-molded stranded wire obtained in the aforementioned manner and a 61-conductor wire having a critical current value Ic of 50 A, which was obtained by engaging 61 conductors and thereafter drawing, rolling and heat treating the same similarly to comparative example prepared in relation to Example 5, were measured by an energization four-probe method. Consequently, the ac loss of the flat stranded wire was 0.1 mW/m while that of comparative example was 4 mW/m in energization under 20 A peak . Thus, it has been recognized that the ac loss was reduced to {fraction (1/40)} in the inventive wire.
EXAMPLE 8
The tape-shaped wire 71 shown in FIG. 7 employed in Example 7 was heat treated at 845° C. for 50 hours, and thereafter rolled into a thickness of 0.2 mm. Then, Cr plating was performed on its surface. Then, 12 strands 81 having Cr-plated surfaces were stacked and inserted in a silver flat pipe 86 , as shown in FIG. 11. A multilayer wire 87 obtained in this manner was flat-drawn so that each side was 1 mm, and 12 such wires were further twisted and flat-molded. This wire was heat treated at 840° C. for 50 hours.
FIG. 12 is a sectional view showing the structure of an oxide superconducting wire obtained in the aforementioned manner. Referring to FIG. 12, this wire is a flat-molded stranded wire formed by twisting 12 multilayer wires 87 .
Then, the oxide superconducting wire obtained in the aforementioned manner was subjected to measurement of a critical current value Ic in liquid nitrogen. Consequently, this wire exhibited a value Ic of 150 A.
In this oxide superconducting wire, each superconducting filament had a width of about 30 μm and a thickness of about 3 μm.
Further, ac loss values of the flat-molded stranded wire obtained in the aforementioned manner and a wire obtained by stacking two 61-conductor wires having a critical current value Ic of 70 A, each of which was obtained by engaging 61 conductors, and thereafter drawing, rolling and heat treating the same similarly to comparative example prepared in relation to Example 5, were measured by an energization four-probe method. Consequently, the ac loss of the flat stranded wire was 0.2 mW/m while that of comparative example was 4 mW/m in energization under 20 A peak . Thus, it has been recognized that the ac loss was reduced.
EXAMPLE 9
Two types of wires were prepared by plating surfaces of strands of 1.02 mm in diameter prepared in Example 5 with Mg and Cu in thicknesses of 10 μm. Then, 12 such strands were twisted and flat-molded similarly to Example 1, and thereafter subjected to rolling and a heat treatment twice to form an oxide superconducting flat-molded stranded wire.
In the superconducting wires obtained in this manner, Cu on the surfaces of strands was oxidized into CuO while Mg was also oxidized into MgO by the heat treatment which was repeated twice. Consequently, the strands were substantially completely insulated from each other.
Then, a critical current value Ic in liquid nitrogen was measured as to the oxide superconducting wire obtained in the aforementioned manner. Consequently, this wire exhibited a value Ic of 98 A. Thus, it is understood that Cu or Mg is entirely is oxidized in the heat treatment so that only oxide films of CuO or MgO are formed on the strand surfaces when the Mg or Cu plating films formed on the strand surfaces are sufficiently reduced in thickness. Thus, it has been confirmed that the superconductivity of the wire was not influenced by Mg or Cu in this case.
Further, ac loss was measured as to the oxide superconducting wire obtained in the aforementioned manner. Consequently, ac loss in energization under 20 A peak was 0.01 mW/m in the case of forming CuO films on the strand surfaces, and 0.02 mW/m in the case of forming MgO films on the strand surfaces. Thus, it has been confirmed that bonding loss between the strands could be extremely reduced in both cases.
EXAMPLE 10
A solution which was prepared by dispersing alumina powder in an organic solvent was applied to the surfaces of the strands of 1.02 mm in diameter prepared in Example 5. Then, 12 such strands were twisted and flat-molded similarly to Example 1, and thereafter subjected to rolling and a heat treatment twice to prepare an oxide superconducting flat-molded stranded wire.
In the superconducting wire obtained in the aforementioned manner, alumina was uniformly dispersed in the surfaces of the strands by the heat treatment which was repeated twice. Consequently, the strands were substantially completely insulated from each other.
Then, the oxide superconducting wire obtained in the aforementioned manner was subjected to measurement of a critical current value Ic in liquid nitrogen. Consequently, this wire exhibited a value Ic of 89 A.
Further, ac loss was measured as to the oxide superconducting wire obtained in the aforementioned manner. Consequently, ac loss in energization under 20 A peak was 0.02 mW/m, and it has been confirmed that bonding loss between the strands could be extremely reduced.
EXAMPLE 11
Strands and a flat-molded stranded wire were prepared under conditions absolutely similar to those of Example 5, except that an Ag—Mn or Ag—Au alloy pipe was employed as a sheath material in place of the silver pipe. The obtained superconducting wire was subjected to measurement of a critical current value Ic in liquid nitrogen and ac loss under 51 Hz and 20 A peak . Table 1 shows results of comparison of characteristics.
TABLE 1
Comparative
Example
Example
Example
Example 5
Example 6
11
11
Sheath
Ag
Ag
Ag
Ag-Mn
Ag-Au
Material
(Matrix)
High
no
no
Cr, Ni
no
no
Resistance
Phase
Structure
four
flat-
flat-
flat-
flat-
stacked
molded
molded
molded
molded
layers
Ic
100A
110A
105A
90A
108A
AC Loss
0.5
0.05
0.01
0.03
0.02
(51 Hz,
mW/m
mW/m
mW/m
mW/m
mW/m
20 A peak)
Referring to Table 1, it has been recognized that bonding loss between strands is considerably reduced and ac loss is consequently reduced when a silver alloy of high resistance is employed for metal coatings of the strands.
EXAMPLE 12
FIG. 13 is a perspective view showing the structure of an exemplary oxide superconducting cable conductor according to the present invention, and FIG. 14 is a sectional view thereof.
Referring to FIGS. 13 and 14, this oxide superconducting cable conductor is formed by spirally assembling oxide superconducting wires 58 of Example 5 shown in FIG. 4 on a Cu pipe 9 in two layers. The first and second layers are assembled in S twist (anticlockwise) and Z twist (clockwise) respectively. The oxide superconducting cable conductor obtained in this manner was subjected to measurement of a critical current value Ic in liquid nitrogen. Consequently, this cable conductor exhibited a value Ic of 1500 A.
For the purpose of comparison, four layers of 61-conductor wires having a critical current value Ic of 25 A, each of which was obtained by engaging 61 conductors and thereafter drawing, rolling and heat treating the same similarly to the comparative wire prepared in relation to Example 5, were assembled on a Cu pipe of the same size as the above, to prepare a cable conductor having a critical current value Ic of 1500 A. Ac loss values were measured as to these two cable conductors. Consequently, the stranded wire two-layer conductor according to the present invention exhibited a value which was smaller by two digits than that of the four-layer conductor of comparative example.
EXAMPLE 13
The flat-molded stranded wire 52 prepared in Example 5 as shown in FIG. 3, which was not yet rolled and heat treated, was employed as a core so that 16 strands 51 employed in Example 5 were wound on its periphery, and flat-molded. This wire was rolled into a thickness of 2 mm, and thereafter heat treated at 845° C. for 50 hours. Then the wire was rolled into a thickness of 1.9 mm, and thereafter heat treated at 840° C. for 50 hours.
FIG. 15 is a sectional view showing the structure of the oxide superconducting wire obtained in the aforementioned manner.
Then, the oxide superconducting wire obtained in the aforementioned manner was subjected to measurement of a critical current value Ic in liquid nitrogen. Consequently, this wire exhibited a value Ic of 230 A.
In this oxide superconducting wire, each superconducting filament had a width of about 110 μm, and a thickness of 9 μm.
As comparative example, 10 wires each obtained by engaging 61 conductors and thereafter drawing, rolling and heat treating the same similarly to Example 5 were stacked, rolled into a thickness of 2 mm and heat treated at 840° C. for 50 hours, to be subjected to measurement of a critical current value Ic. Consequently, this wire exhibited a value Ic of 250 A.
Further, ac loss values of the aforementioned two types of wires were measured by an energization four-probe method. Consequently, the ac loss of the flat stranded wire was 0.3 mW/m while that of comparative example was 2 mW/m in energization under 100 A rms . Thus, it has been recognized that the ac loss was reduced.
EXAMPLE 14
The flat-molded stranded wire prepared in Example 6 was employed to prepare an oxide superconducting cable conductor having the same structure as Example 12. The obtained oxide superconducting cable conductor exhibited a critical current value Ic of 1400 A in liquid nitrogen. Further, this conductor exhibited ac loss which was lower by 100% than that of the cable conductor according to Example 12.
Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims. | Provided are an oxide superconducting wire which maintains a high critical current density and has a small current drift with small ac loss when the same carries an alternating current and a method of preparing the same, and a cable conductor which is formed by assembling such oxide superconducting wires. The oxide superconducting wire is a flat-molded stranded wire which is formed by twisting a plurality of metal-coated strands consisting of an oxide superconductor, and is characterized in that the flat-molded stranded wire has a rectangular sectional shape, and a section of each strand forming the flat-molded stranded wire has an aspect ratio (W1/T1) of at least 2. The method of preparing this oxide superconducting wire comprises the steps of preparing a stranded wire by twisting a plurality of strands, each of which is formed by metal-coating an oxide superconductor or raw material powder therefor, flat-molding the prepared stranded wire, and repeating rolling and a heat treatment of at least 800° C. on the flat molded stranded wire a plurality of times. | 48,690 |
This is a Continuation in Part of application Ser. No. 09/846,719 filed May 1, 2001 now U.S. Pat. No. 6,484,902. The entire contents of application Ser. No. 09/846,719 is incorporated herein. This application claims the benefit of U.S. Provisional Application Serial No. 60/200,920, filed May 1, 2000.
BACKGROUND OF THE INVENTION
This invention relates to methods and apparatus for material handling, and more particularly, for agitating and/or dispensing materials in a predetermined manner.
In the manufacture of products, it is often necessary to dispense and sort items, such as components used in assemblies or subassemblies, in some ordered manner, such that those items can then be used in subsequent manufacturing processes. These items might be delivered into containers, onto a conveyor belt, or directly to another machine. In other applications, it may be desirable to dispense and sort bulk granular or particulate materials. For the purposes herein, such components or other materials are collectively referred to for simplicity purposes generally as “items,” “products,” or “product.”
In certain applications, it may be necessary to not only deliver items in batches of an approximate predetermined quantity, but also to orient those items as they are dispensed such that those items may be more easily manipulated by machines, such as perhaps robots, or by workers, for subsequent use. It may also be desirable to dispense the items into another feeding device, the first such dispensing device then essentially taking on the role of a pre-feeder. Further, if the items are of a mixed nature, for example having two or more different components in a batch, it may be necessary to differentiate and separate the items into groups of their own kind during the dispensing process.
Other problems may arise in dispensing items, particularly in a production environment. Such items may become entangled with one another, and thus frustrate dispensing of such items in a controlled manner. Also, depending on the product being dispensed, static electricity may build up such that the product clings to the hopper or other container in which the product is held. Moisture can also cause a problem with such product by increasing the likelihood of adhesion of the items in groups.
Further, mechanical agitation or vibration of the items, such as is found in certain conventional dispensing devices, could potentially damage delicate items prior to being dispensed for subsequent use.
A dispenser may also be used for dispensing parts or components for certain manufacturing processing steps, such as de-flashing, cleaning, drying, counting, visual inspection, random selection, testing, chemical treatment, painting, coating, labeling, recycling, crushing, etc.
Various material handling devices have been patented. U.S. Pat. No. 4,118,074, issued to Solt, discloses a pulsed air activated conveyor for transporting bulk material. U.S. Pat. No. 4,848,974, issued to Wayt, discloses a system for the fluidized conveyance of flat articles, such as lids or bottoms for cans. U.S. Pat. No. 4,182,586, issued to Lenhart also discloses an air operated material handler, wherein jets of air are used to separate and align bulk storage items such as containers. U.S. Pat. No. 4,578,001, issued to Ochs et al., discloses an air conveyor hopper having air nozzles positioned on a rotating feed disc for engaging and carrying items.
While the foregoing designs are known, there still exists a need for improved methods and apparatus to perform mixing and dispensing of product.
AIR PULSE FEEDER
SUPPLEMENT TO THE BACKGROUND
Teoh et al. In U.S. Pat. No. 6,116,822 discloses the use of a vertical jet of air into a plurality of parts in order to agitate the parts and break up their bridge over a dispensing aperture. This jet of air, however is not described, illustrated, nor configured to take advantage of Bernoulli's principle by which the rapid motion of air might create a vacuum that could draw into the parts hopper a volume of air greater than that supplied by the jet itself. The closed nature of the connection between hopper and channel leading to the pick up location prohibit the free flow of ambient air necessary to effect such an amplification of air flow.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a dispensing system for dispensing products.
Another object of the present invention is to provide a method of dispensing products.
Another object of the present invention is to provide a method and apparatus for detangling products.
Yet another object of the present invention is to provide a method and apparatus for orienting products.
A still further object of the present invention is to provide a method and apparatus for detangling and orienting products.
A further object of the present invention is to provide a method and apparatus for sorting products.
A still further object of the present invention is to provide a method and apparatus for mixing products.
Generally, the present invention includes a dispensing apparatus for dispensing items from a plurality of items and comprises a container having a support surface for supporting the plurality of items, the container having an upper portion and an opening in the upper portion for receiving the plurality of the items. The container also has an open passageway in a lower portion thereof for dispensing items from the container. At least one pressurized fluid outlet is provided for delivering a pulse of pressurized fluid through the open passageway into the container of sufficient pressure to lift the plurality of items above the support surface, and at least one guide surface is provided for directing at least one of the plurality of items through the open passageway subsequent to the delivery of the pulse of pressurized fluid.
More specifically, the present invention includes an apparatus and methods for dispensing and/or mixing a variety of products on a predetermined or automated basis. The system uses pressurized fluid and a controller such as a programmable logic controller (“PLC”), microprocessor, or the like, to mix and/or dispense product upon application of compressed fluid pulses to the product. Products are “fluidized” by the pulse of compressed fluid provided to the hopper, the compressed fluid preferably being a compressed gas such as air, although other gases or fluids, and in particular, inert gases could be used, depending on the specific application.
The present invention allows for products such as small components, parts, or particles to be dispensed from a batch contained in a compartment or hopper. Such products may be. dispensed to containers, various types of conveyances, or other dispensers, feeders, magazines, cartridges, or another machine for further processing.
The pulse application of compressed air temporarily lifts and levitates the items in the hopper, while simultaneously blanketing them in the flow of air. Upon termination of the pulse, the items again drop, due to force of gravity, into the hopper, but due to the lifting and levitation of the items caused by the pulse, one or more items may be reoriented such that as the pulse flow ceases, such items are properly orientated to pass through a dispensing door or opening, such as a slot, in a lower portion of the hopper. The remaining items in the hopper, by their nature, may again become entangled or otherwise contact one another as they fall into place in the hopper after the pulse flow, such that such items bridge the dispensing slot to thereby prevent the remaining products from passing therethrough.
An analogous example of how the present invention operates is the shaking of the salt shaker in order to release salt on a food item. In certain instances, inverting the salt shaker will allow the flow of granular salt through tiny openings in the salt shaker. However, over time, the salt within the salt shaker may bridge the openings thereby preventing further flow of salt. This requires the salt shaker to again be either shaken, or reverted to its normal position and then reinverted in order to once again begin flow of the salt.
Products dispensed as a result of the pulse flow, or “blast,” are generally dispensed in a row which, if a conveyance such as a conveyor belt is used, could be oriented to be transverse to the direction of travel of the conveyor belt, or, in line with the conveyor belt travel to allow for a more continuous line of products to be provided on the conveyor belt.
Control may be maintained over the dispensing rate and distribution of products being dispensed and this allows for an approximate predetermined quantity of products to be dispensed with each pulse of pressurized fluid, in a manner which may be independent of actual pulse frequency.
The pulses can be programmed to be made infrequently, in a series of intermittent predetermined sequences, or continuously with the frequency of hundred, or perhaps a thousand or more, pulses per minute.
Further, the present invention can provide dispensing in synchronism with the movement and speed of other machines in response to signals of one or more sensors which may be provided on the present dispensing system, and, the system can be configured to dispense products and parts of similar shape and size oriented in a predetermined direction.
SUPPLEMENT TO THE SUMMARY OF THE INVENTION
The objectives of this invention include providing a method and apparatus for mixing, untangling, orienting, separating, dispensing, and feeding items from a plurality of items to some receiving apparatus, mechanism, or container.
This application gives additional emphasis and makes additional claims to important aspects of the invention. Specifically, much of the effectiveness of this invention comes from it's power to generate a vacuum that draws into the container, through the open passageway at the bottom of the container, significant volumes of pulsed fluid. The fluid brought in by vacuum is normally the main mover of the plurality of items. This use of pulsed vacuum to draw in pulsed fluid through the dispensing aperture is a distinguishing feature for this invention over the prior art.
The present invention includes an apparatus comprised of a container with a support surface, an opening in the upper portion for receiving items, a passageway in the lower portion for dispensing items, a guide surface to direct items into the passageway, a means for generating pulses of vacuum that draw pulses of air (or other fluid) into the container through the open passageway, and sufficient volume of available air outside the passageway and outside the container to fill the vacuum generated inside the container. The pulses of fluid serve to lift and separate items immediately above and around the passageway.
In many cases the items in the immediate area of the passageway and beyond are fluidized.
There is a natural tendency for items thus lifted and separated to “flow” out the passageway upon termination of the pulse, as the air forced in and expanded by the sudden vacuum is now released to collapse and return to the lower pressure area created outside the container by the abrupt departure of the air from outside the container to the inside. This means that items inside the container might exit faster than if they were dependent upon gravity alone. The retreating air is forcing them along. It also means the items are less likely to immediately re-jam since the natural vacuums created by the moving fluid tend to align the items with the path the air takes upon it's retreat out the passageway. There is also a tendency for items thus buffered with air to be better protected from damage than if vibration or other direct contact with some more rigid impetus moved them.
This application describes a variety of means to generate pulses of vacuum that in turn draw pulses of air (or other fluid) into the container through the passageway. These include the use of pulses of pressurized air into the container through the passageway, near the open passageway and in a second container, which extends into the lower portion of the primary container as well as other approaches. The use of thin sheets of pressurized air as provided by air knives and the use of laminar flow of air against supporting surfaces and guide surfaces further enhance the effectiveness of these pulses. When using vacuum pulses farther removed from the passageway it becomes important, during those pulses; to close the top opening in the container designed for supplying items. Otherwise, the power of the vacuum to draw air in through the passageway at the bottom of the container could be greatly diminished.
The invention teaches varying the size of the passageway. This can be especially helpful when dealing with more than a single configuration of items over time.
The invention teaches the inclusion of another container within the main container. Such a container can be used to block the area directly above the passageway from a large portion of the items in the main container. This can reduce the pressure on the items immediately above the passageway. This in turn reduces the necessary volume of air and level of pressure required to achieve satisfactory lift and separation of items to be dispensed at any given time. Such a container may also be configured to supply pulses of vacuum in the immediate area of the passageway.
The invention teaches the associated use of means to orient items to be dispensed and the associated use of means to separate various configurations of items.
The invention teaches the use of air funnels to enhance the effect of pulses of vacuum for moving the maximum volume of air into the container through the passageway.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing, as well as other objects of the present invention, will be further apparent from the following detailed description of the preferred embodiment of the invention, when taken together with the accompanying specification and the drawings, in which:
FIG. 1 is a perspective view of the dispensing system constructed in accordance with the present invention;
FIG. 2 is a partial perspective view of a dispensing system constructed in accordance with the present invention;
FIG. 3 is a side elevational view of a dispensing system constructed in accordance with the present invention, wherein the dispensing slot is in a dosed configuration;
FIG. 4 is a side elevational view of the dispensing system shown in FIG. 3, with the dispensing slot in an open position;
FIG. 5 is a perspective view of an air knife constructed in accordance with the present invention;
FIG. 6 is a sectional view taken along lines 6 — 6 of FIG. 5;
FIG. 7 is an exploded view of an air knife constructed in accordance with the present invention;
FIG. 8 is a schematic view of a dispensing system constructed in accordance with the present invention, wherein products to be dispensed are shown being held in a hopper;
FIG. 9 is a sectional view taken along lines 9 — 9 of FIG. 3;
FIGS. 10A-10F illustrate capsules, beans, tablets, electronic chips, fuses, and capacitors, respectively, all of which may be dispensed using the dispensing system of the present invention;
FIG. 11A is a simplified plan view of a dispensing system constructed in accordance with the present invention;
FIG. 11B is a simplified front elevational view of the dispensing system shown in FIG. 11A; and
FIG. 11C is a simplified right side elevational view of the dispensing system illustrated in FIG. 11 A.
SUPPLEMENT TO THE BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing, as well as other objects of the present invention, will be further apparent from the following description of the drawings and preferred embodiments of the invention, when taken together with the accompanying specifications and the drawings including all the information from the original application included herein, in which:
FIG. 12 is a cross section of a preferred embodiment of said invention illustrating a source for pulsed fluid outside the container that generates pulses of vacuum thereby drawing into the container ambient fluid from outside the container. The figure illustrates one configuration of an air funnel below the container to enhance the efficiency of the vacuum. It also shows sections of a guide surface and support surface configured to help align parts.
FIGS. 13-A and 13 -B illustrate parts being lifted and separated during pulses of vacuum and parts flowing down and out the dispensing aperture between pulses.
FIG. 14 is a cross section of a preferred embodiment of said invention illustrating a sealed top to the container with a removable lid. This cross section also illustrates pressurized fluids entering the container from within the lower portion of the container as a means for generating pulses of vacuum.
FIG. 15 is a cross section of a preferred embodiment of said invention illustrating an interchangeable part used to vary the size and shape of the open passageway by blocking part of the opening. This figure also illustrates delivery of pulses of vacuum through a second container within the main container (hopper) thereby drawing into the container ambient fluid from outside the container through the lower opening. In this case the vacuum source is not shown.
FIG. 16 is a cross section of a preferred embodiment of said invention illustrating the use of an interchangeable part to replace the open passageway itself in another size.
FIG. 17 . is a cross section of a preferred embodiment of said invention with interchangeable exit apparatus. Several examples of exit apparatus are shown.
FIG. 18 . shows two sections of a preferred embodiment of the invention illustrating one way to use the invention as a separator.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The accompanying drawings and the description which follows set forth this invention in its preferred embodiment. However, it is contemplated that persons generally familiar with material handling systems and methods will be able to apply the novel characteristics of the structures illustrated and described herein in other contexts by modification of certain details. Accordingly, the drawings and description are not to be taken as restrictive on the scope of this invention, but are to be understood as broad and general teachings.
Referring now to the drawings in detail, wherein like reference characters represent like elements or features throughout the various views, the mixing and dispensing system of the present invention is indicated generally in the figures by reference character 10 , such system 10 being suitable for practicing of the methods of the present invention.
As generally shown in FIGS. 1 and 11 A- 11 C, the dispensing system includes a generally V-shaped hopper, generally H, mounted on a base structure, generally 12 . Brackets 14 are attached to the base and carry journal rods 18 which are received in bores 19 of air knives, generally K Air knives K are carried for sliding movement on rods 18 , in a manner to be discussed in more detail below. Fixedly connected to the air knives K are end walls 20 , 22 of hopper H. Hopper H has four walls, end walls 20 , 22 forming two of those walls, and side walls 24 , 26 forming the remaining two walls. End walls 20 , 22 flare outwardly from one another, and the lower portions of the end walls 20 , 22 meet at the apex 30 of the hopper H, when the hopper H is in a “closed” position, as shown in FIG. 3 . When the hopper H is in a “dispensing” position, as shown in FIG. 4, the. end walls 20 , 22 are separated from one another to form a dispensing slot, generally S, for dispensing products, generally P, from the compartment, or interior portion, generally 34 , of the hopper H.
Both end walls 20 , 22 may be moveable laterally with respect to one another, or only one end wall may be moveable, with the other end wall being fixed. The side walls 24 , 26 , which are generally triangularly-shaped, are configured for generally vertical movement with respect to the end walls 20 , 22 , end walls 20 , 22 having elongated slots 38 for receipt of bolts 40 of side walls 24 , 26 .
Movement of the side walls 24 , 26 is accomplished by fluid actuators, generally A, such as pneumatic actuators, operating from a compressed air supply (not shown). It is to be understood, however, that other types of actuators could be used, such as solenoids, motors, spring mechanisms, etc., if desired, to open a dispensing slot in the lower portion of hopper H. Actuation of the actuators A is accomplished using conventional valving techniques and also includes the use of a programmable logic controller (PLC) (not shown) or other controller, such a microprocessor. Compression springs 44 are provided on rods 18 in order to force air knives K, end walls 20 , 22 to a normally closed position, wherein the dispensing slot S is closed. Activation of the actuators A forces side walls 24 , 26 upwardly or downwardly (as discussed in more detail below), which in turn forces one or more end walls 20 , 22 and corresponding air knives K inwardly or outwardly, respectively, as such are connected to end walls 20 , 22 . Upon deactivation of the supply of pressurized air to actuators A, compression springs 44 force air knives K back towards one another, and compression springs 54 likewise, force actuators A to their centered, “home,” position to force side walls 24 , 26 upwardly to thereby close dispensing slot S.
Pressurized air is provided to actuators A via hoses 52 A, 52 B, and pressurized air is also intermittently provided to inlets 53 of air knives K through hoses 50 for pulsing purposes.
As shown in FIG. 9, a hinged cover 60 is provided for selectively covering the opening 62 of hopper H, such cover including filter material, generally 64 , carried with grate 66 , for allowing air to pass upwardly therethrough, while also preventing product from being expelled upwardly from hopper H during the pulses of compressed air and also for preventing contaminants from entering hopper H and contaminating the products contained therein. Preferably, filter material overlaps the upper portion of side walls 24 , 26 somewhat to accommodate the upward and downward movements of the side walls.
FIG. 2 illustrates cover 60 in an open position exposing interior portion 34 of hopper H. Cover 60 is connected to hopper H via hinge, generally 61 , as shown in FIGS. 3, 4 , and 10 .
The opening and closing of dispensing slot S is performed using a unique system. An elongated bar 66 is attached to each side wall 24 , 26 , such as by welding. Thus, bar 66 moves upwardly and downwardly with side walls 24 , 26 .
Cam followers 68 are carried in cam follower supports 69 , which are fixedly attached to each end wall 20 , 22 . Cam followers 68 are allowed to freely rotate with respect to cam supports 69 and ride upon a camming surface 81 of bar 70 which is carried for sliding movement with respect to the bar 66 . In other words, camming bar 70 may shift from side to side, as shown by arrow 71 in FIG. 4 .
Fixedly attached to camming bar 70 are brackets 72 to which actuator A is attached. Actuator A is preferably a double action cylinder having a rod 73 extending therethrough with a central piston number 74 . The cylinder portion 75 of actuator A is fixedly attached to brackets 72 , and the ends of rod 73 are each fixedly attached to bar 66 through use of shoulder bolts 76 , which act as guides within slots 77 provided on each end of camming bar 70 . Compression springs 54 normally urge cylinder portion 75 of actuator A to a central position, substantially equal distantly spaced between rod ends 78 , when actuator A is not pressurized.
Upon pressurization of actuator A, the cylinder portion 75 of actuator A may move to one side or the other, since the ends 78 of rod 73 are fixed to bar 66 . This shifting from side to side of cylinder 75 causes a corresponding shifting of cam bar 70 . Detents 78 are provided on cam bar 70 and are used to open and close dispensing slot S through interaction of cam follower 68 therewith. For example, as shown in FIG. 3, cam followers 68 are resting within detents 78 . In this configuration, the dispensing slot S is closed. However, as shown in FIG. 4, cam bar 70 has been shifted to the left, through introduction of pressurized air through hose 52 B, which forces cam follower 68 upwardly out of detents 78 . This causes a corresponding downward movement of side plates 24 , 26 , as shown by arrow 79 , against the force of compression springs 44 , which consequently forces the ends 90 of end walls 20 , 22 and air knives K apart. This opens dispensing slot S to allow product P to be dispensed therefrom. It is to be noted that ordinarily, the force of compression springs 54 act through end walls 20 , 22 to force side walls 24 , 26 upwardly, and that the downward movement of side walls 24 , 26 in opening dispensing slot is performed against the force of springs 54 .
As shown in FIG. 4 introduction of air into air hose 52 B would cause the leftward movement of cam bar 70 , as shown by arrow 71 , to open dispensing slot S. However, if air is bled from hose 52 B, springs 54 would effectively force cylinder 75 to the centermost position, such that cam followers 68 again are received in detents 78 . This would in turn, force side walls 24 , 26 upwardly, and the compression action of springs 44 would force air knives K, and end walls 20 , 22 together, to thereby close dispensing slot S. Alternately, compressed air could be introduced to hose 52 A to shift cylinder 75 to the right to open dispensing slot S.
Note that the width of the dispensing slot can be changed by changing the location of the detents 78 in camming bar 70 . Camming bar 70 may include an additional camming surface 80 opposite camming surface 81 , with detents 82 having different relative positions with respect to detents 78 . This allows the same camming bar 70 to be used, by flipping it over, to yield a different width for dispensing slot S.
FIGS. 4, 6 , and 8 also illustrate dispensing passageway, or opening, S in an open configuration. Note that end walls 20 , 22 has been moved apart by the downward movement of side walls 24 , 26 , which in essence “pry” end walls 20 , 22 apart in order to create dispensing slot S. Note that side wall 24 has moved downwardly such that the lower tip thereof extends beyond the bottom edge 90 of end walls 20 , 22 .
FIG. 1 shows product P, which could be capsules, electronic chips, etc. which have been deposited on the conveyor belt 94 . Note in this example that the elongated dispensing slot S extends parallel to the direction of travel of the conveyor belt 94 . Therefore, the product P is deposited in a generally continuous line on the conveyor belt 94 . In other applications, however, the conveyor belt could run transverse to the dispensing slot such that the product is deposited in spaced apart, transversely extending rows across the width of the conveyor belt.
FIGS. 5-7 illustrate air knives K in detail. The assembly is held together with screws 96 and includes an air knife plate 98 , and a shim, or orifice plate, generally 100 , having a cut-out portion which defines the gap 101 through which air flows from the air knife K.
FIG. 8 illustrates product P such as electronic chips, capsules, etc. held in the hopper H when the dispensing slot S is open. This could be a configuration of the product P between pulses of pressurized air or other fluid. Note how the individual items, in conjunction with other items, serve to bridge the dispensing opening S to prevent other items from falling through the opening S. Upon a blast of pressurized air through the air knives K, however, such items would be lifted and levitated and agitated such that when such subsequent blast ends, the product will again fall downwardly, and this time the items which are properly oriented fit through the slot opening (which is of predetermined width and length), will fall through the opening.
FIGS. 10A through 10F illustrate a brief sampling of typical items which could be dispensed using dispensing system 10 . Such items include capsules, as shown in FIG. 10A, beans as shown in FIG. 10B, tablets, shown in FIG. 10C, electronic chips, shown in FIG. 10D, fuses, shown in FIG. 10E, and capacitors, shown in FIG. 10 F. By virtue of the blasts of air provided by the present invention, items which could be prone to entanglement, such as the electronic chips (FIG. 10D) and capacitors (FIG. 10F) could become separated and untangled from one another. With respect to mixing of items, the present invention could differentiate capsules shown in FIG. 10 A and tablets shown in FIG. 10C, if both were carried with the hopper, by simply varying the opening of the dispensing slot such that it would only dispense items the thickness of the tablets. Thus, assuming the capsules were a different thickness, the capsules would remain in the hopper, while the tablets would continue to be dispensed upon application of the blasts of compressed air, thereby effectively sorting the capsules and the tablets.
FIG. 11A illustrates hopper H, and also dispensing slot S in an open configuration. FIG. 11B illustrates the positioning of air knives K beneath hopper H, and FIG. 11C illustrates the hopper H with the dispensing slot S in an open position.
In operation, product, such as small parts, components, or other items are placed within the compartment 34 of hopper H. An ordinary. switch (not shown) is activated such that the PLC energizes a conventional solenoid valve (not shown) causing it to open and deliver compressed air from a compressed air source (not shown) to the hoses 52 A, 52 B connected to actuators A. Although not shown, such compressed air could be conditioned by passing the air through a dehumidifier or humidifier (if necessary), air filter, and pressure regulator prior to entering actuators A Movement of the cylinder 74 on rod 68 extending from the actuators A causes a change in the variable geometry of the hopper H, by moving one or more end walls 20 , 22 outwardly with respect to the other. The selective movement of the actuators A also causes side walls 24 , 26 to move downwardly to force a separation between side walls 20 , 20 and the air knives K to separate and form dispensing slot S, which is of a venturi shape, at the bottom of the hopper H.
As the dispensing slot S becomes open, the PLC activates a conventional quick response valve (not shown) causing it to open for a predetermined number of milliseconds. Compressed air passes through the valve and then enters chamber 110 located in and extending the substantial length of each air knife K. The compressed air then accelerates through elongated thin orifice 101 , on the order of 0.002-0.006 inches, preferably, and through an outlet 114 provided in each air knife K. The resulting pressurized air flow exhibits laminar flow characteristics such that the air flow exhausted from the outlet generally stays attached to the curved forward surfaces 116 of the air knives K, as shown by arrows 118 , due to the Coanda effect, which thus causes the air flow to change direction as it flows upwardly. The air flow continues upwardly into the hopper H and tends to follow the surfaces of the outwardly-flared end walls 20 , 22 before eventually becoming turbulent.
As the accelerated and expanding air emitted from the air knives K blasts into the hopper H, entangled and bridged items lodged in and blocking the dispensing opening S are disbursed by the force of the blast. The air flow quickly becomes turbulent and is completely diffused, while passing through the interstitial spaces between the items in the hopper. The initial burst of air causes the items in the hopper to become essentially fluidized, and, accordingly, the air generally coats the items with a thin layer of protective air. The effect of the blast of air, which begins as a laminar flow and then becomes turbulent, causes a separation and mixing of the contents of the hopper. Should items come into contact with each other, this contact would potentially be of reduced force, due to the blanket of air surrounding such items.
When the pulse of air ends, the upward momentum of the parts is overcome by gravity, and the ambient barometric pressure fills the partial vacuum created by the sudden expansion of the product caused by the pulses of air. This is believed to essentially defluidize the items as they fall down to the open dispensing slot S, and it is also believed that the descent of the product is accelerated by the sudden contraction of air into the area of relative vacuum created by the expansion of the items.
The items nearest to the bottom of the hopper H arrive first at the dispensing slot S. Since such items are now spread apart and relatively fluidized, they tend to align themselves with the narrow opening of the dispensing slot, thereby forming a row. Flowing on a thin layer of protective air, the items flow out generally unimpeded through the dispensing slot S between the air knives, and on to some form of conveyance, or into a bin, further dispensing device, machine, etc. in a suitable condition to facilitate proper orientation for subsequent use.
The items that remain in the hopper H tend to congregate and entangle in the base of the hopper thereby forming bridges across the dispensing opening S and becoming lodged there. The “pile” or other conglomeration of the product is thus generally reestablished, as such of the pulse items are no longer fluidized, since the air movement of the pulse has ended. Further, the weight of the upper portion of the pile compresses the bottom layer of items bridging the dispensing opening, thereby holding such bridging items in place and blocking the opening. This condition remains until another pulse of air occurs.
Beginning with the activation of the quick response valve, this same scenario takes place again, with the exception of the dispensing opening S, which remains open until the desired number of items are dispensed, or the hopper is empty. At this point, the PLC deactivates the solenoid valve controlling air flow to the actuators A, and air is bled off from the pneumatic actuators using conventional bleed-off valves or other relief fittings (not shown). This allows compression springs 54 located on the rods 73 to cause actuators A to return to their home position. This causes side walls 24 , 26 to move upwardly, and allows the air knives K and end walls 20 , 22 to be forced together by compression springs 44 . The movement of the end walls 20 , 22 and the air knives K together reestablishes the hopper H back to its original shape and geometry,. with the dispensing opening S closed.
The present invention is particularly suited for processing components or parts with traits that cause problems for conventional feeders, since the present invention uses different methods and applies additional principles of physics and aerodynamics. Conventional feeders may force components to move in a way which is harmful to the component, whereas the present invention, by suspending product in air, tends to reduce the possibility of product damage.
The present invention does not force items through a restriction while they are in a pile and entangled with one another. Instead, the items are lifted, separated, fluidized, mixed, and untangled and then allowed to align themselves naturally with a relatively narrow and controlled dispensing opening.
The dispensing system of the present invention can also be used with mixed batches in order to separate desired products from other products which may have been inadvertently left in the hopper. Also, components which may be prone to sticking together due to static electricity or because of moisture are more easily managed due to the blasts of air which continually move, separate and agitate the products.
In determining the appropriate width of the dispensing opening, such width is preferably narrower than the longer dimension of the items which must pass therethrough. This allows for better control over the items, by aligning their narrowest dimension with that of the dispensing opening each time they are pulsed with air.
Preferably, the hopper is of modular design with the end walls and/or side walls being readily exchangeable to permit providing a hopper of a different height, and/or width, if necessary. The outward incline of end walls 20 , 22 , which can be varied depending on the particular application, provides guide surfaces for product towards dispensing slot S. This would necessitate a corresponding change of the triangular shaped side walls 24 , 26 to accommodate the changed incline of end walls 20 , 22 . Further, the dispensing system should find applicability as a retrofit to existing machines requiring dispensing of product because of its versatile and readily variable modular design. A preferred range for the angle between end walls 20 , 22 is between 60 and 90 degrees.
The present invention may be used for dispensing and/or mixing a wide variety of materials and components. In certain applications, component sizes may range from approximately {fraction (1/64)}th of an inch to ⅝th of an inch across their shortest dimension, with {fraction (1/32)}nd of an inch to ½ inch being typical. However, it is to be understood that these dimensions are for illustrative purposes, and the present invention could be sized to accommodate materials with smaller or larger dimensions, depending on the particular application.
In certain applications mixing or agitation of product may be desired, even if dispensing of the product is not needed at that time. In such an event, dispensing slot S could simply remain only partially open, to prevent dispensing of the product, while pulsing the product with compressed air or other fluid.
For extremely small product P, such as granular material, fine powder, etc., a limitation may be reached based on the correlation of density, shape, texture, and the resulting aerodynamic drag of such material. For example, particles which are too small and light, such as fine powder, may float in the air when subjected to the pulsed fluid blasts of the present invention. Another limitation as to size involves parts or components which may be too large and too heavy, as a practical matter, because such parts would require a relatively large amount of compressed fluid to be used to lift and agitate such parts during the dispensing operation. Also, the use of such large amounts of pressurized fluid or compressed air could also present noise problems. It is to be understood, however, that the present invention could be used for such large products in situations where the dispensing abilities of the present invention outweigh such concerns.
The maximum applicability of the present invention would typically lie with components which range between small, dense items and relatively large volume items which are of less density. Further, components having surface configurations which are readily engageable by a fluid flow would be better suited for the present invention than would be spherical items, such as ball bearings. However, if small ball bearings, approximating the size of BBs, could be dispensed if such ball bearings were mixed with non-spherical items, such as oblong shaped parts.
The present invention finds particular use in dispensing and/or mixing items that are subject to damage or abrasion which may result from rubbing or impact forces of conventional dispensing devices. The present dispensing system is also desirable for components which may, from time to time, become mixed with other types of components. Further, the present invention finds use with components which need to be fed rapidly in large numbers or fed continuously at a constant and specific rate, or fed periodically, or in a series of intermittent patterns, or in unison with other process. Further, the present dispensing system can be used for components which are to be dispensed spaced apart from one another, for example, along a moveable conveyor belt, or for components which need to be dispensed aligned in a continuous row or file, or alternately, aligned in a series or rows or ranks. Components which are wet or which carry lubricating oils, or which tend to stick to each other when combined together, may be dispensed by the present dispensing system, as could also components which are required to be maintained or lubricated while in contact with one another in a batch configuration. Moreover, the present invention is suitable for components that are subject to static electric clinging, and finally, for general purpose components having no special or unique needs or requirements.
EXAMPLES
It is anticipated that the present invention may be used to dispense and/or mix a variety of materials, products and components, including but not limited to, the items listed below:
A. Electrical parts, such as fuses, capacitors, resistors, connectors, chips, microprocessors, etc.
B. Medicines or vitamins, such as pills, tablets, capsules, gel caps, etc.
C. Small mechanical parts, such as screws, washers, rivets, bolts, gears, bushings, nuts, pins, etc.
D. Diced foods, or foods shaped as small objects, such as candies, beans, cereals, macaroni, pasta, etc.
E. Pelletized or granular foods, such as those fed to farm animals, zoo animals, pets, etc.
F. Pelletized or granular chemicals, such as fertilizers, cleaning supplies, explosives, etc.
G. Agricultural products, such as rice, wheat, grains, oats, seeds, berries, nuts, etc.
H. Plastic parts, such as media, buttons, fittings, caps, spacers, toy parts, etc.
I. Rubber parts, such as O-rings, grommets, seals, gaskets, erasers, etc.
From the foregoing, it can be seen that the present invention provides a versatile system for dispensing and/or mixing a variety of materials and items through its ability to cause a strong aerodynamic effect upon such items. Through adjustment of the geometries of the hopper, the pulse frequency and duration, the dispensing opening, fluid pressure, flow rates, directions of the pressurized fluid flow, and timing and sequencing of the fluid flow blasts, the dispensing and mixing characteristics of the present invention can be varied, as desired. Moreover, by virtue of the design of the present invention, a precise and exacting adjustment may not be necessary in order to nevertheless maintain adequate control of the dispensing of products.
To accommodate products of particular dimensions, the geometric shape, dimensional ratios, etc. of end walls 20 , 22 and side walls 24 , 26 of the hopper can be varied to obtain the desired width for accommodating such products. Further, the width of the dispensing outlet can readily be varied depending on component size, as can the pulse frequency, duration, and pressure of the fluid used to lift and agitate products in the hopper. More specifically, pressurized fluid volumetric flow rates could be varied simply by varying the diameter of the compressed air supply lines 50 , and the blast or “spray” pattern of the pressurized fluid to which the products are subjected can be readily varied by changing the width of the air knives outlets 114 or simply the orifice plate 100 . Also, although not shown, sensors could be provided to detect various parameters of dispensing system 10 , and such sensors connected to a PLC for controlling operation of system 10 in response to the output of such sensors.
While preferred embodiments of the invention have been described using specific terms, such description is for present illustrative purposes only, and it is to be understood that changes and variations to such embodiments, including but not limited to the substitution of equivalent features or parts, and the reversal of various features thereof, may be practiced by those of ordinary skill in the art without departing from the spirit or scope of the following claims.
SUPPLEMENT TO THE DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to the drawings in detail, wherein like reference characters represent like elements or features throughout the various views, the mixing and dispensing system of the present invention is indicated generally by “ 10 ”.
Referring now to FIG. 12; pulses of pressurized fluid 252 , are emitted from the chamber 110 through a narrow opening whose size is determined by the spacer 100 . Due to the Coanda effect, the fluid tends to remain close to the surface as that surface turns upward into the container H. The container H serves as a hopper to hold parts P for processing. In this figure one surface 210 is indicated as a guide surface. The other surface 220 is indicated as a support surface. In this particular configuration, however, both surfaces serve as both support and guide surfaces. “V” shaped, parallel groves 211 in guide surface 210 help to align parts P as they move downward against the guide surface. Parallel fins 221 are perpendicular to support surface 220 . The fins 221 help to align parts P as they move downward against the support surface. Sections a-A and b-B of surfaces 210 and 220 respectively, show these surface configurations from another view. As is consistent with Bernoulli's principle, the pulses of pressurized fluid create a vacuum which in turn draws into the container H pulses of ambient fluids 260 from outside the hopper up through the opening S in the lower portion of the container. The drawing power of the pressurized fluid is enhanced by air funnel 240 . The opening 0 in the top of the container allows for the addition of parts P into the hopper for processing. The opening S in the lower portion of the container also serves as dispensing aperture for parts as is illustrated in other figures.
Referring now to FIGS. 13-A; the illustration shows the lower portion of a preferred embodiment of the present invention. Pulses of pressurized fluid 252 are emitted from the chamber 110 through a narrow opening whose size is determined by the spacer 100 . Due to the Coanda effect, the fluid tends to remain close to the surface as that surface turns upward into the container. The container serves as a hopper to hold parts P for processing. In this figure one surface 210 is indicated as a guide surface. The other surface 220 is indicated as a support surface. In this particular configuration, however, both surfaces serve as both support and guide surfaces. As is consistent with Bernoulli's principle, these pulses of pressurized fluid create a vacuum which in turn draws into the container H pulses of ambient fluids 260 from outside the hopper up through the opening S in the lower portion of the container. The drawing power of the pressurized fluid is enhanced by air funnel 240 . The upward pulse of fluid lifts and separates parts P as indicated in FIG. 13-A by the space between parts and the arrows flowing upward between parts.
FIG. 13-B shows the same parts P as the pulse ends, the fluid “collapses” and begins to retreat through open passageway S. The parts not only fall, but also are also swept along by and buffered by the retreating fluid 261 . The parts tend to align themselves with the flow of fluid and so pass through the open passageway faster, with less product damage, and in larger quantities than would be normal for parts that were simply dropped or shaken to give them impetus to pass through the open passageway S. This downward flow of fluid and parts is indicated by the generally lower position of parts P and the downward arrows 261 between and around the parts. This downward flow may be ended by the equalization of pressure within and without the container, by bridging of the parts over the open passageway S, and/or by the next upward pulse of fluid through open passageway S.
Referring now to FIG. 14; pulses of pressurized fluid 252 are emitted from the chamber 256 through a narrow opening inside the lower portion of hopper H. Due to the Coanda effect, the fluid tends to remain close to the surface as that surface turns upward within hopper H. In this figure one surface 210 is indicated as a guide surface. The other surface 220 is indicated as a support surface. In this particular configuration, however, both surfaces serve as both support and guide surfaces. As is consistent with Bernoulli's principle, these pulses of pressurized fluid create a vacuum which in turn draws into the hopper pulses of ambient fluids 260 through opening S from outside the hopper. The opening O in the top of the container allows for the addition of parts, shown in other figures, into the hopper for processing. The removable lid 235 for the opening O allows for the opening O to be closed or opened as desired. The opening S in the lower portion of the container also serves as dispensing aperture for parts as is illustrated in other figures. The parts are lifted and separated by these vacuum pulses and subsequently flow out the dispensing aperture S between pulses the same as illustrated in other figures.
FIG. 15 . presents a preferred embodiment of invention 10 and illustrates the use of an interchangeable (drop in) part 270 used to block part of the established open passageway S. By changing the size and/or shape of the open passageway in this simple manner, it may be unnecessary to have additional whole dispenser machines when changing items or when it is desired to separate items of a smaller size from standard items. In many instances the changes in opening size and shape that are possible with such a simple device as this can also serve to orient items as they exit the container. This figure also illustrates a second container 230 within the hopper. When the main container H is loaded with parts P as illustrated in other figures, the second container 230 blocks the area directly above the passageway from a large portion of the parts. This reduces the pressure on the items immediately above the passageway. This in turn reduces the necessary volume of air and level of pressure required to achieve satisfactory lift and separation of items to be dispensed at any given time. The second container 230 supplies vacuum pulses near the lower aperture. The second container 230 is sealed to a conduit 269 in its upper portion.
Pulses of vacuum 268 are supplied from another source at the opposite end (not shown) of the conduit. This in turn draws pulses of fluid 260 from outside the container through the opening S as reduced in size by the interchangeable part 270 . The air funnel 240 enhances the efficiency of this influx of fluid 260 . The opening S in the lower portion of the container also serves as dispensing aperture for parts as is illustrated in other figures. The parts are lifted and separated by these vacuum pulses and subsequently flow out the dispensing aperture S between pulses the same as illustrated in other figures.
FIG. 16 . illustrates a preferred embodiment 10 of this invention. In this case no air funnel 240 is shown, though it might well be added to enhance the influx of fluid. An interchangeable device 275 is shown as a replacement for that section of the container defining the opening S. In this case the interchangeable element 275 provides a smaller opening. Other such interchangeable elements might provide larger openings, subdivide the opening into multiple openings or change the shape of the opening. This is similar in function to the “drop in”, interchangeable element 270 shown in FIG. 15 . As described, however, 270 adds material to the existing apparatus and would therefore never increase the size of the opening. The design of such interchangeable elements will directly affect the flow of fluids and the flow of parts in the overall apparatus 10 . A second container 230 is shown within the hopper H. When the main container H is loaded with parts P as illustrated in other figures, the second container 230 blocks the area directly above the passageway from a large portion of the parts. This reduces the pressure on the items immediately above the passageway. This in turn reduces the necessary volume of air and level of pressure required to achieve satisfactory lift and separation of items to be dispensed at any given time. The second container 230 supplies vacuum pulses near the lower aperture. The second container 230 is sealed to a conduit 269 in its upper portion. Pulses of vacuum 268 are supplied from another source at the opposite end (not shown) of the conduit. This in turn draws pulses of fluid 260 from outside the container through the opening S as modified by the interchangeable part 275 . These pulses will then effect movement and flow of parts from hopper H as described and illustrated in other Figures.
FIG. 17 illustrates a preferred embodiment 10 of this invention incorporating an interchangeable exit apparatus 280 . Such an exit apparatus may be located within the open passageway S or below the open passageway as illustrated here. Example variations of this exit apparatus 280 -A, 280 -B, 280 -C and 280 -D are also illustrated. These interchangeable parts of various configurations can serve multiple functions. Some configurations of exit apparatus may simply vary by size, as is the case between 280 -A and 280 -B. This shift in size may serve to accommodate the dispensing of different sized items when they are processed through the apparatus at different times. This shift may also be used to separate items of different sizes when they are processed in the apparatus at the same time. In another case 28 b-A might be used with rectangular solids as well as more rounded items when a range of item orientations are acceptable. But, 280 -C might be preferred with rectangular solids when a more restricted orientation of parts is required. 280 -D shows an alternative in which the upper opening of the exit apparatus is round and could accept round or rectangular solids of appropriate size. In this case, however, the profile of the exit apparatus changes as it progresses downward. This allows the exit container to further orient a generally rectangular solid as it passes through and out of the exit apparatus. Many variations of size and-shape are possible and will be useful depending upon the parts themselves and subsequent operations involving those parts. This figure also shows a second container 230 within the main container H. When the main container H is loaded with parts P as illustrated in other figures, the second container 230 blocks the area directly above the passageway from a large portion of the parts. This reduces the pressure on the items immediately above the passageway. This in turn reduces the necessary volume of air and level of pressure required to achieve satisfactory lift and separation of items to be dispensed at any given time.
FIG. 18 . shows two views (section a—a and section b—b) of a preferred embodiment 10 of the invention used as a separator. A pre-feeder 245 supplies the hopper H with two configurations of a plurality of items P at one end of the trough shaped container H. Pulses of pressurized fluid 252 are emitted from a pressurized chamber 110 , which extends the length of hopper H through a gap that is also the length of hopper H. Spacer 100 determines the width of the gap. The open passageway S is sized to allow only the smaller of the items (the white ones) to pass through while the larger items (the shaded ones) remain in the hopper. The hopper has a slight decline leading away from the prefeeder toward two receptacles 310 and 320 at the opposite end of the hopper. As the items P are repeatedly lifted, separated and then flow downward toward the open passageway S the smaller items pass through the open passageway onto a conveyor C while the larger items are moved farther and farther down the hopper and eventually into receptacle 310 . The conveyor C carries the smaller articles to receptacle 320 . The angle of decline, the length of the trough, the volume of items being pre-feed to the hopper and variations in the pulses of pressurized fluid all affect the effectiveness of separating out the smaller parts before the larger parts are delivered into receiving apparatus 310 .
These figures illustrate many features of preferred embodiments independently of one another in some cases and in limited combinations in other cases. Such figures are intended to illustrate various features, but are not intended to limit the combinations of various features with one other. In fact, it is anticipated that variations in combinations of features will be normal in order to meet the needs of various manufacturing operations. In similar fashion, there are many unillustrated features that will be obvious to those of ordinary skill in the art based on the descriptions and claims made here. They include, but are not limited to, (1) vacuum pumps and other sources of vacuum pulses, (2) inlets for vacuum pulses into the container at places other than the lower portion of the container, (3) combination of the various features of this invention with other systems such as physical vibrations, sonic vibrations, magnetic, pneumatic and hydraulic pressure, etc.
Preferred embodiments of the invention have been described using specific terms. Such description is for present illustrative purposes only. It is to be understood that changes and variations to such embodiments may be practiced by those of ordinary skill in the art without departing from the spirit or scope of the following claims. Such variations may include, but are not limited to, the substitution of equivalent features or parts and the reversal of various features thereof. | A dispensing system that includes an apparatus comprised of a container with a support surface, an opening in the upper portion for receiving items, a passageway in the lower portion for dispensing items, a guide surface to direct items into the passageway, a means for generating pulses of vacuum that draw pulses of air (or other fluid) into the container through the open passageway, and sufficient volume of available air (or other fluid) outside the passageway and outside the container to fill the vacuum generated inside the container. A preferred method of generating the vacuum pulses is injecting pulses of high-pressure fluid in thin sheets into the container through the open passageway with laminar flow against the support or guide surfaces. Items are lifted and separated by the influx of fluid. Upon termination of pulses, the volume inside the container collapses and items, carried by and buffered by exiting fluid, pass through the open passageway often at speeds in excess of those that would be generated by gravity alone. | 59,136 |
REFERENCE TO RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent application Ser. No. 08/153,053, filed Nov. 17, 1993, now U.S. Pat. No. 5,504,316 which is a continuation-in-part of U.S. patent application Ser. No. 07/868,401, filed Apr. 14, 1992, now U.S. Pat. No. 5,280,165, which in turn is a division of application Ser. No. 07/520,464, filed May 8, 1990, now U.S. Pat. No. 5,168,149.
This application is also related to U.S. patent application Ser. No. 08/294,438, filed Aug. 23, 1994, which is a continuation of Ser. No. 08/037,143, filed Mar. 29, 1993 now abandoned, which is a division of Ser. No. 07/715,267, filed Jun. 14, 1991, now U.S. Pat. No. 5,235,167.
This application is also related to Ser. No. 08,271,729, filed, Jul. 7, 1994, which is a continuation of Ser. No. 07/981,448, filed Nov. 25, 1992, now abandoned.
This application is also related to Ser. No. 08/028,107, filed Mar. 8, 1993.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention generally relates to a scanner module for use in an optical scanner, for example, a bar code scanner.
2. Description of the Related Art
A typical optical scanner (for example a bar code scanner) has a light source, preferably a laser light source, and means for directing the laser beam onto a symbol (for example a bar code) to be read. On route to the symbol, the laser beam is generally directed onto, and reflected off, a light reflecting mirror of a scanning component. The scanning component causes oscillation of the mirror, so causing the laser beam repetitively to scan the symbol. Light reflected from the symbol is collected by the scanner and detected by a detector such as a photodiode. Decode circuitry and/or a microprocessor algorithm is provided to enable the reflected light to be decoded, thereby recovering the data which is recorded by the bar code symbol.
Scanners of this general type have been disclosed, for example, in U.S. Pat. Nos. 4,251,798; 4,360,798; 4,369,361; 4,387,297; 4,593,186; 4,496,831; 4,409,470; 4,808,804; 4,816,661; 4,816,660; and 4,871,904, all of which patents have been assigned to the same assignee as the present invention, and all of which are hereby incorporated by reference.
In recent years, it has become more common for bar code scanners to have within them a distinct scanner module containing all the necessary mechanical and optical elements needed to create the scanning of the laser beam and to deal with the incoming reflected beam from the bar code that is being scanned. Using a separate scanner module, within the housing of the bar code scanner, facilitates a modular approach to design and manufacture, thereby keeping costs down, improving reliability, and facilitating the transfer of scanning technology to a variety of scanner housings. A typical prior art scanner module is disclosed in U.S. Pat. No. 4,930,848, to Knowles.
There are a large number of known ways of mounting a mirror within the scanning component to cause the necessary scanning motion of the laser beam. Some provide for oscillation in only a single direction, so that the scanning laser beam traces out a single path across the bar code being scanned. Others provide two dimensional scanning patterns, such as for example raster patterns or patterns of greater complexity. Examples of scanning components allowing two dimensional scanning are shown in U.S. Pat. No. 5,280,165, and in European Patent Application 540,781. Both of these are assigned to the same assignee as the present invention, and are hereby incorporated by reference.
As optical scanning systems have become more complex, and as the demand for smaller size and lower power consumption has increased, shock protection for the scanner modules has become more difficult. These highly efficient scan engines, with both resonant and nonresonant scanning elements are difficult to protect because the scanning element must be free to move for scanning but must be protected in the event of a shock (for example if the user drops the bar code scanner within which the scanner module is incorporated). Also, as sizes are reduced manufacturing tolerances begin to have more significant impacts on costs. Furthermore, it becomes more difficult to achieve accurate optical alignment during assembly and to maintain that optical alignment during the life of the product.
SUMMARY OF THE INVENTION
Objects of the Invention
It is a general object of the invention at least to alleviate the problems of the prior art.
It is an additional object to provide a scanner module in which the scanning element is protected against shock.
It is a further object to provide a scanner module of increased compactness.
It is a further object to provide a robust, compact scanner module having reduced manufacturing/assembly costs.
FEATURES OF THE INVENTION
According to an aspect of the present invention there is provided a scan module for use in a scanner for reading indicia having parts of differing light reflectivity, the scan module comprising:
a) a frame;
b) a scanning component mounted to the frame for oscillatory motion, the scanning component including an optical element for directing light in a scanning pattern across an indicia to be read, the scanning component having an aperture therein;
c) an anti-shock member, passing through the
aperture in the scanning component, the anti-shock member being smaller in cross section than the size of the aperture, thereby providing clearance for the scanning component to oscillate in use, but preventing excessive movement of the scanning component with respect to the frame in the event that the module is subjected to a mechanical shock.
According to a further aspect of the invention there is providing a method of assembling a scan module for use in a scanner for reading indicia having parts of differing reflectivity, the scan module comprising: a frame; a scanning component to be mounted to the frame for oscillatory motion, the scanning component including an optical element for directing light in a scanning pattern across an indicia to be read, the scanning component having an aperture therein; and an anti-shock pin having a first head portion, a second head portion, and a waist portion having a smaller cross section than the first and second head portions; the method comprising: the following steps:
a) positioning the scanning component adjacent to the frame;
b) partially inserting the pin into the frame so that the second head portion passes through the aperture and extends from the aperture into a correspondingly-shaped bore in the frame, thereby aligning the scanning component with respect to the frame;
c) securing the scanning component to the frame; and
d) continuing insertion of the pin into the frame so that the waist portion of the pin becomes located within the aperture, thereby providing clearance for the scanning component to oscillate in use, but preventing excessive movement of the scanning component with respect to the frame in the event that the module is subjected to a mechanical shock.
According to a further aspect of the invention there is provided a scan module for use in a scanner for reading indicia having parts of differing light reflectivity, the scan module comprising:
a) a frame;
b) a scanning component comprising a bracket mounted to the frame by flexible support means for oscillatory motion, the bracket carrying an optical element for directing light in a scanning pattern across an indicia to be read;
c) an electromagnetic coil mounted to the frame;
d) magnet means secured to the bracket adjacent the coil; and
e) the bracket further including a counterweight portion balancing the mass of the optical element at the flexible support means, the counterweight portion at least partially overlying the coil.
According to yet a further aspect of the invention there is provided a scan module for use in a scanner for reading indicia having parts of differing light reflectivity, the scan module comprising:
a) a frame;
b) a scanning component comprising a main bracket mounted to the frame by flexible support means for oscillatory motion, the main bracket carrying an optical element for directing light in a scanning pattern across an indicia to be read, the main bracket having an aperture therein;
c) an electromagnetic coil mounted to the frame;
d) magnet means, secured to the bracket adjacent to the coil;
e) the bracket further including a counterweight portion balancing the mass of the optical element at the flexible support means, the counterweight portion at least partially overlying the coil; and
f) an anti-shock member passing through the aperture in the main bracket, the member being smaller in cross section than the size of the aperture, thereby providing clearance for the scanning component to oscillate in use, but preventing excessive movement of the scanning component with respect to the claim in the event that the module is subjected to a mechanical shock.
Preferably, the scanning component comprises a main bracket (for example of a beryllium copper alloy) which includes a pair of hanging brackets by which the main bracket is secured to the frame. Each hanging bracket has attached to it a thin strip of a polyester film, the strip being secured at one end to the hanging bracket and at the other end to the frame. The main bracket therefore hangs from the frame on the strips. The strips can flex, allowing the main bracket to oscillate.
The main bracket desirably carries an optical element, such as a mirror, for directing light onto onto it in a scanning pattern across the indicia to be read. The mirror may be secured to the main bracket by a further flexure, allowing the mirror to oscillate independently of the main bracket. If the flexure supporting the mirror and the strips are arranged to flex in mutually perpendicular directions, two dimensional scanning patterns (such as raster patterns) can be produced.
The strips may be protected from mechanical shock by first and second anti-shock pins which pass through apertures in the hanging brackets. The diameter of the central portions of the pins is slightly smaller than the diameter of the apertures, thereby allowing the main bracket to oscillate in use. However, if a shock is applied to the scan module, the pins prevent excessive movement of the main bracket, and hence prevent over-stressing of the strips.
Each anti-shock pin may include an enlarged head portion, which is of substantially the same size and shape in cross section as the aperture in the respective hanging bracket. This allows the main bracket to be accurately positioned with respect to the frame during assembly of the scan module, when the pin is in a partially-inserted position. Once the position has been accurately determined, the main bracket may be secured to the frame, and the pins fully inserted.
The invention may be carried into practice in a number of ways, and one specific embodiment will now be described, by way of example, with reference to the accompanying drawings. The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The preferred features of the invention, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will best be understood from the following description, when read in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded perspective view of a scanner module embodying the present invention;
FIG. 2 is a partially assembled view of the scanner module of FIG. 1;
FIG. 3 is a fully assembled view of the scanner module of FIG. 1;
FIG. 4 is a view from below of the scanner module of FIG. 1;
FIG. 5 shows, schematically, details of the scanning mechanism; and
FIG. 6 shows the range of oscillation of the scanning element.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference will be made, first of all, to FIGS. 5 and 6 which show, schematically, details of the scanning arrangement. Following a description of these figures, reference will then be made to FIGS. 1 to 4 which show how the preferred scanning arrangement of FIGS. 5 and 6 may be incorporated into a scanning module.
The scanning arrangement 170 shown in FIG. 5 comprises an electromagnetic coil 172 having a central opening into which partially extends a permanent magnet 174. The coil 172 is rigidly secured to a support member (not shown), and the magnet 174 is resiliently coupled to the same support by means of an arm 176.
A U-shaped spring 178 is attached to the magnet 174 at one end, and the opposite end of the spring supports an optical element, preferably a reflector 180. Electrical leads (not shown) carry an energizing current or drive signal to the coil 172. The reflector 180 will oscillate in response to such electromagnet coil signal so as to scan in one or two dimensions, selectively. The spring 178 may be made of any suitable flexible materials, such as a leaf spring, a flexible metal coil or a flat bar having sufficient flexibility properties, and may be of a material such as a beryllium-copper alloy.
The reflector 180 is positioned between a laser beam source and lens assembly 182 and a target (not shown in FIG. 5). Between the reflector 180 and source 182 is a collector 184 having an 181 opening through which a light beam emitted by the laser source 182 may pass to the reflector 180. The collector is oriented so as to direct incoming light, reflected by reflector 180 and then collector 184, to a photodetector 186.
An important aspect of the embodiment of FIG. 5 is that the mass of reflector 180 is considerably less than the mass of permanent magnet 174. The mass of the mirror is selected to be less than about one-fifth the mass of the magnet, and the angle of vibration of the mirror as shown in FIG. 6, a diagram derived by computer simulation, is about seven times that of the permanent magnet.
The reflector 180 is capable of 2-D scanning. As described in copending application Ser. No. 07/943,232, filed on Sep. 10, 1992, the U-shaped spring 178 is formed of a plastic material, such as Mylar or Kapton. The arms of the U-shaped spring 178 and the planar spring 176 may be arranged to vibrate in planes which are orthogonal to each other. Mylar is a registered trademark of E. I. du Pont de Nemours and Co., Inc. for polyester material. Oscillatory forces applied to permanent magnet 174 by the electromagnetic coil 172 can initiate desired vibrations in both of the springs 178 and 176 by carefully selecting drive signals applied to various terminals of the coil, as discussed in the copending application. Because of the different frequency vibration characteristics of the two springs 178 and 176, each spring will oscillate only at its natural vibration frequency. Hence, when the electromagnetic coil 172 is driven by a signal having high and low frequency components, the U-shaped spring 178 will vibrate at a frequency in the high range of frequencies, and the planar spring 176 will vibrate at a frequency in the low range of frequencies.
A feature of the embodiment of FIG. 5 is that the laser beam emitted by source 182 impinges the reflector 180 at an angle that is orthogonal to the axis of rotation of the reflector. Hence, the system avoids droop in the 2-D scan pattern that tends to arise when the angle of incidence of the laser beam is non-orthogonal to the reflective surface.
Another feature of FIG. 5 is in the folded or "retro" configuration shown, with the laser beam source 182 off axis from that of the beam directed from the reflector 180 to the target. The detector field of view follows the laser path to the target by way of collector 184. The folded configuration shown is made possible by opening 181 in the collector. The retro configuration enables the scanning mechanism to be considerably more compact than heretofore possible.
Reference should now be made to FIGS. 1 to 4, which illustrate the preferred scanner module within which the scanning arrangement of FIGS. 5 and 6 may be incorporated. For ease of reference, parts of the module already described with reference to FIGS. 5 and 6 will be given the same reference numerals.
As may best be seen in the exploded view of FIG. 1, the preferred scanner module consists of two separate sections: a chassis element 10 and a scan element 12. In FIG. 1, these two sections are shown in exploded form, prior to their securement together during the assembly process.
As is best seen in FIGS. 3 and 4, the chassis element 10 comprises a chassis 14 which carries the coil 172. The coil 172 is secured to a rear wall 16 of the chassis. At respective ends of the rear wall there are first and second forwardly-extending side supports 18, 20. The forward end of the side support 18 is provided with a vertical slot 22 (FIG. 3) into which is placed (FIG. 4) the collecting mirror 184 previously referred to. The forward part of the other side support 20 is provided with a larger vertical slot or cavity 24 (FIG. 3) into which the photodiode assembly 186 (FIG. 4) fits.
The features of the scan element 12 (which is during assembly secured to the chassis element 10) is best seen from a comparison of FIGS. 1, 2 and 4. The scan element comprises a beryllium-copper bracket generally shown at 26 having a vertical mounting portion 28 in a plane perpendicular to the axis of the coil 172. The upper part of the mounting portion is formed with two rearwardly-pointing prongs 30, 32 (not visible in FIG. 4). Secured to the mounting portion 28 is the spring 178, previously mentioned with reference to FIG. 5, which carries the mirror 180. On either side of the prongs 30, 32, the upper edge of the mounting portion 28 is bent backwardly to form first and second hanging brackets (34, 36, best seen in FIGS. 1 and 2). Screwed to these hanging brackets are respective first and second sheets of Mylar film 38, only one of which is visible in FIGS. 1 to 3. At the top of the Mylar sheets are secured respective hangers 40, 42.
The scanner module is assembled by bringing the scan element 12 up to the chassis element 10 and using screws 44, 46 to attach the hangers 40, 42 to respective bosses 48, 50 on the chassis side supports 18, 20. The relative positioning of the chassis element and the scan element, just prior to their securement together by the screws 44, 46 is shown most clearly in FIG. 2.
It will be appreciated that once the scanner module has been assembled, as described, the entire weight of the scan element, including the mirror 180, is supported by the hangers 40, 42 and the sheets of Mylar film 36, 38. The entire scan element is accordingly free to rock back and forth about a horizontal axis perpendicular to the axis of the coil 172 as the Mylar film flexes.
The operation of the device will now be described, with reference to FIG. 4. A laser beam, emanating from the laser beam source and lens assembly 182, passes through the hole 181 in the collector 184, and impinges upon the mirror 180 from which it is reflected via a window 52 to a bar code symbol to be read (not shown). Energization of the coil 172 causes oscillation of the mirror 180 in two directions: a first direction due to flexing of the spring 178 and a second direction due to flexing of the Mylar film 38. By appropriate control of the coil, a variety of scanning patterns can be produced, for example a raster pattern or other types of two-dimensional pattern.
Light reflected back from the bar code symbol passes back through the window 52, impinges on the mirror 180, and is reflected to the collector 184. The collector concentrates the light and reflects it back to the photo detector 186. Decoding circuitry and/or a microprocessor (not shown) then decode the signals received by the photo detector 186, to determine the data represented by the bar code.
It might be thought that because the entire weight of the scan element 12 is taken by the Mylar film 38, the system is likely to be very vulnerable to shocks, for example if the user accidentally knocks or even drops the bar code scanner within which the module is contained. However, provision has been made for that contingency by way of an anti-shock feature which will now be described.
First, as may be seen in FIGS. 2 and 3, the lower end of the hanging bracket 34 is located within a channel 54 formed in the side support 18 of the chassis. As the Mylar film 38 flexes, the hanging bracket 34 moves back and forth within the channel 54. The Mylar film 38 is prevented from over-flexing by the walls of the channel 54 which act as stops. A similar arrangement (not visible in the drawings) is provided on the other side.
A second level of protection is provided by alignment pins 56, 58, best seen in FIG. 1. Each pin comprises a threaded rear head portion 60, a reduced diameter smooth waist portion 62, and a smooth forward head portion 64.
In its operational position, shown in FIG. 3, the waist portion 62 of the pin passes through a hole 68 in the hanging bracket 34, with the forward head portion 64 being received within a correspondingly-sized blind bore 70 within one side of the channel 54. The rear head portion 60 of the pin is screwed into and held in place by a threaded bore 66 which opens at its forward end into the channel 54 and at its rearward end into the rear surface of the rear wall 16. There is a similar arrangement on the other side (not shown) for the second alignment pin 58.
The diameter of the waist portion 62 of the pin is some 0.02 inches smaller than the diameter of the hole 68 in the hanging bracket. This provides sufficient tolerance for the Mylar to flex slightly during normal operation of the device. However, if the module is dropped the presence of the pin prevents over-stressing and perhaps breaking of the Mylar.
The alignment pins have a further function of assisting accurate positioning of the scan element 12 with respect to the chassis during assembly. During assembly, the scan element is brought up into approximately the correct position, and the alignment pins are then inserted as shown in FIG. 2. At this point, the forward head portion 64 is a tight tolerance sliding fit both within the hole 68 in the hanging bracket and in the blind bore 70. This aligns the scan element to the pins and hence to the chassis. The scan element is then secured to the chassis, as previously described, using the screws 44, 46. The hangers 40, 42 provide a certain amount of adjustability or tolerance in positioning, thereby ensuring that the scan element can be attached to the chassis at the position defined by the alignment pins. The pins are then fully screwed into the threaded bores 66 until the end of the pin is flush with the rear face 16 of the chassis. At this point, as is shown in FIG. 3, the forward head portion of the pin has been received within the bore 70, and the waist portion has moved up to its final position within the hole 68 of the hanging bracket.
It will be understood that each of the elements described above, or any two or more together, may also find a useful application in other types of constructions differing from those described.
While the invention has been illustrated and described as embodied in a particular scanner module arrangement, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the stand point of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims. | A scanner module for use in a bar code reader has a scanning mirror which is mounted to a bracket by way of leaf-spring, allowing the mirror to oscillate in one direction. The bracket is hung from a stationary chassis by means of two strips of mylar film, allowing the entire bracket to oscillate in the perpendicular direction, thereby providing two dimensional oscillation of the mirror and raster scanning of a light beam reflected from the mirror. The mylar sheets are protected against mechanical shock by pins which pass through holes in the bracket. The pins are slightly smaller than the holes, allowing sufficient clearance for movement of the bracket during normal operation, but preventing too much stress being placed upon the mylar films if the module is dropped. The pins also provide accurate alignment of the bracket with respect to the chassis. | 24,572 |
RELATED APPLICATIONS
This is a continuation in part application of U.S. patent application Ser. No. 10/878,805, filed Jun. 28, 2004 now U.S. Pat. No. 7,332,408, titled “ISOLATION TRENCHES FOR MEMORY DEVICES,” which application is commonly assigned, the entire contents of which are incorporated herein by reference.
TECHNICAL FIELD OF THE INVENTION
The present invention relates generally to memory devices and in particular the present invention relates to isolation trenches for memory devices.
BACKGROUND OF THE INVENTION
Memory devices are typically provided as internal storage areas in computers. The term memory identifies data storage that comes in the form of integrated circuit chips. In general, memory devices contain an array of memory cells for storing data, and row and column decoder circuits coupled to the array of memory cells for accessing the array of memory cells in response to an external address.
One type of memory is a non-volatile memory known as flash memory. A flash memory is a type of EEPROM (electrically-erasable programmable read-only memory) that can be erased and reprogrammed in blocks. Many modern personal computers (PCs) have their BIOS stored on a flash memory chip so that it can easily be updated if necessary. Such a BIOS is sometimes called a flash BIOS. Flash memory is also popular in wireless electronic devices because it enables the manufacturer to support new communication protocols as they become standardized and to provide the ability to remotely upgrade the device for enhanced features.
A typical flash memory comprises a memory array that includes a large number of memory cells arranged in row and column fashion. Each of the memory cells includes a floating-gate field-effect transistor capable of holding a charge. The cells are usually grouped into blocks. Each of the cells within a block can be electrically programmed on an individual basis by charging the floating gate. The charge can be removed from the floating gate by a block erase operation. The data in a cell is determined by the presence or absence of the charge on the floating gate.
Memory devices are typically formed on semiconductor substrates using semiconductor fabrication methods. The array of memory cells is disposed on the substrate. Isolation trenches formed in the substrate within the array and filled with a dielectric, e.g., shallow trench isolation (STI), provide voltage isolation on the memory array by acting to prevent extraneous current flow through the substrate between the memory cells. The isolation trenches are often filled using a physical deposition process, e.g., with high-density plasma (HDP) oxides. However, the spacing requirements for flash memory arrays often require the isolation trenches to have relatively narrow widths, resulting in large aspect (or trench-depth-to-trench-width) ratios. The large aspect ratios often cause voids to form within the dielectric while filling these trenches using physical sputtering processes.
Filling the trenches with spin-on-dielectrics (SODs) can reduce the formation of voids within the dielectric during filling. However, spin-on-dielectrics usually have to be cured (or annealed) after they are disposed within the trenches, e.g., using a steam-oxidation process that can result in unwanted oxidation of the substrate and of layers of the memory cells overlying the substrate. To protect against such oxidation, the trenches can be lined with a nitride liner prior to filling the trenches with a spin-on-dielectric. One problem with nitride liners is that they can store trapped charges that can adversely affect the reliability of the memory cells and thus the memory device.
For the reasons stated above, and for other reasons stated below which will become apparent to those skilled in the art upon reading and understanding the present specification, there is a need in the art for alternatives to existing trench-fill methods.
SUMMARY
The above-mentioned problems with filling isolation trenches and other problems are addressed by the present invention and will be understood by reading and studying the following specification.
For one embodiment, the invention provides a method of forming a portion of an integrated circuit device contained on a semiconductor substrate. The method includes removing a portion of the substrate to define an isolation trench and forming a first dielectric layer on exposed surfaces of the substrate in the trench. Forming a second dielectric layer on at least the first dielectric layer, where the second dielectric layer contains a different dielectric material than the first dielectric layer is included in the method. The method includes depositing a third dielectric layer to fill the trench, removing an upper portion of the third dielectric layer from the trench and leaving a lower portion covering a portion of the second dielectric layer, and oxidizing the lower portion of the third dielectric layer after removing the upper portion. Removing an exposed portion of the second dielectric layer from the trench, thereby exposing a portion of the first dielectric layer is included in the method, as is forming a fourth dielectric layer in the trench covering the exposed portion of the first dielectric layer.
For another embodiment, the invention provides a method of forming a portion of an integrated circuit device contained on a semiconductor substrate. The method includes removing a portion of the substrate to define an isolation trench and forming a first dielectric layer on exposed surfaces of the substrate in the trench. Forming a second dielectric layer on at least the first dielectric layer, where the second dielectric layer contains a different dielectric material than the first dielectric layer is included in the method. The method includes partially filling the trench with a silicon rich oxide material, oxidizing the silicon rich oxide material, causing surplus silicon of the silicon rich oxide material to form silicon oxide. Removing an exposed portion of the second dielectric layer from the trench, thereby exposing a portion of the first dielectric layer is included in the method, as is forming a third dielectric layer in the trench covering the exposed portion of the first dielectric layer.
Further embodiments of the invention include methods and apparatus of varying scope.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified block diagram of a memory system, according to an embodiment of the invention.
FIGS. 2A-2H are cross-sectional views of a portion of a memory device during various stages of fabrication, according to another embodiment of the invention.
FIG. 3 is a cross-sectional view of a portion of a memory device during a stage of fabrication, according to yet another embodiment of the invention.
FIGS. 4A-4E are cross-sectional views of a portion of a memory device during various stages of fabrication, according to still another embodiment of the invention.
DETAILED DESCRIPTION
In the following detailed description of the invention, reference is made to the accompanying drawings that form a part hereof, and in which is shown, by way of illustration, specific embodiments in which the invention may be practiced. In the drawings, like numerals describe substantially similar components throughout the several views. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. Other embodiments may be utilized and structural, logical, and electrical changes may be made without departing from the scope of the present invention. The term wafer or substrate used in the following description includes any base semiconductor structure. Both are to be understood as including silicon-on-sapphire (SOS) technology, silicon-on-insulator (SOI) technology, thin film transistor (TFT) technology, doped and undoped semiconductors, epitaxial layers of a silicon supported by a base semiconductor structure, as well as other semiconductor structures well known to one skilled in the art. Furthermore, when reference is made to a wafer or substrate in the following description, previous process steps may have been utilized to form regions/junctions in the base semiconductor structure, and terms wafer or substrate include the underlying layers containing such regions/junctions. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined only by the appended claims and equivalents thereof.
FIG. 1 is a simplified block diagram of a memory system 100 , according to an embodiment of the invention. Memory system 100 includes an integrated circuit memory device 102 , such as a flash memory device, e.g., a NAND or NOR memory device, a DRAM, an SDRAM, etc., that includes an array of memory cells 104 and a region peripheral to memory array 104 that includes an address decoder 106 , row access circuitry 108 , column access circuitry 110 , control circuitry 112 , Input/Output (I/O) circuitry 114 , and an address buffer 116 . The row access circuitry 108 and column access circuitry 110 may include high-voltage circuitry, such as high-voltage pumps. Memory system 100 includes an external microprocessor 120 , or memory controller, electrically connected to memory device 102 for memory accessing as part of an electronic system. The memory device 102 receives control signals from the processor 120 over a control link 122 . The memory cells are used to store data that are accessed via a data (DQ) link 124 . Address signals are received via an address link 126 that are decoded at address decoder 106 to access the memory array 104 . Address buffer circuit 116 latches the address signals. The memory cells are accessed in response to the control signals and the address signals. It will be appreciated by those skilled in the art that additional circuitry and control signals can be provided, and that the memory device of FIG. 1 has been simplified to help focus on the invention.
The memory array 104 includes memory cells arranged in row and column fashion. For one embodiment, the memory cells are flash memory cells that include a floating-gate field-effect transistor capable of holding a charge. The cells may be grouped into blocks. Each of the cells within a block can be electrically programmed on an individual basis by charging the floating gate. The charge can be removed from the floating gate by a block erase operation.
For one embodiment, memory array 104 is a NOR flash memory array. A control gate of each memory cell of a row of the array is connected to a word line, and a drain region of each memory cell of a column of the array is connected to a bit line. The memory array for NOR flash memory devices is accessed by row access circuitry, such as the row access circuitry 108 of memory device 102 , activating a row of floating gate memory cells by selecting the word line connected to their control gates. The row of selected memory cells then place their data values on the column bit lines by flowing a differing current, depending upon their programmed states, from a connected source line to the connected column bit lines.
For another embodiment, memory array 104 is a NAND flash memory array also arranged such that the control gate of each memory cell of a row of the array is connected to a word line. However, each memory cell is not directly connected to a column bit line by its drain region. Instead, the memory cells of the array are arranged together in strings (often termed NAND strings), e.g., of 32 each, with the memory cells connected together in series, source to drain, between a source line and a column bit line. The memory array for NAND flash memory devices is then accessed by row access circuitry, such as the row access circuitry 108 of memory device 102 , activating a row of memory cells by selecting the word line connected to a control gate of a memory cell. In addition, the word lines connected to the control gates of unselected memory cells of each string are driven to operate the unselected memory cells of each string as pass transistors, so that they pass current in a manner that is unrestricted by their stored data values. Current then flows from the source line to the column bit line through each series connected string, restricted only by the selected memory cells of each string. This places the current-encoded data values of the row of selected memory cells on the column bit lines.
FIGS. 2A-2H are cross-sectional views of a portion of a memory device, such as a portion of the memory device 102 , during various stages of fabrication, according to another embodiment of the invention. FIG. 2A depicts the portion of the memory device after several processing steps have occurred. Formation of the structure depicted in FIG. 2A is well known and will not be detailed herein.
In general, the structure of FIG. 2A is formed by forming a first dielectric layer 202 on a substrate 200 , e.g., of silicon or the like. For one embodiment, the first dielectric layer 202 is a gate dielectric layer (or tunnel dielectric layer), such as a tunnel oxide layer. A conductive layer 204 , e.g., a layer of doped polysilicon, is formed on the first dielectric layer 202 , and a hard mask layer 206 is formed on the conductive layer 204 . The mask layer 206 can be a second dielectric layer, such as a nitride layer, e.g., a silicon nitride (Si 3 N 4 ) layer.
Trenches 210 are subsequently formed through the mask layer 206 , the conductive layer 204 , and the first dielectric layer 202 and extend into substrate 200 . This can be accomplished by patterning the mask layer 206 and etching. A third dielectric layer 212 may then be formed on portions of the substrate 200 exposed by the trenches 210 so as to line the portion of trenches 210 formed in substrate 200 .
A fourth dielectric layer 220 , such as a nitride layer, e.g., a silicon nitride layer, is formed on the structure of FIG. 2A in FIG. 2B , such as by blanket deposition, and acts as an oxidation barrier layer for one embodiment. Specifically, the fourth dielectric layer 220 is formed on an upper surface of mask layer 206 and on portions of the mask layer 206 , the conductive layer 204 , and the first dielectric layer 202 through which trenches 210 pass. The fourth dielectric layer 220 is also formed on the third dielectric layer 212 . In this way, the fourth dielectric layer 220 lines trenches 210 . For one embodiment, the third dielectric layer 212 acts to provide adhesion between substrate 200 and the fourth dielectric layer 220 and acts as a stress release layer for relieving stresses that would otherwise form between substrate 200 and the fourth dielectric layer 220 . For another embodiment, the third dielectric layer 212 is a pad oxide layer and can be a thermal oxide layer. For another embodiment, the third dielectric layer 212 is, for example, a layer of deposited silicon dioxide (SiO 2 ).
A fifth dielectric layer 230 is deposited within each of the trenches 210 on the fourth dielectric layer 220 in FIG. 2C to either fill or partially fill trenches 210 . For one embodiment, the fifth dielectric layer 230 is spin-on dielectric (SOD) material, such as a spin-on glass, hydrogen silsesquioxane (HSQ), hexamethyldisiloxane, polysilazane, octamethyltrisiloxane, etc. The fifth dielectric layer 230 is then cured (or annealed), e.g., using a steam-oxidation process, if necessary. For one embodiment, the fourth dielectric layer 204 acts to prevent oxidation of the substrate 200 and the conductive layer 204 during curing.
For one embodiment, the fifth dielectric layer 230 is formed as shown in FIG. 3 . Each of the trenches 210 is partially filled with a silicon-rich oxide material 330 . The silicon-rich oxide material 330 is then oxidized, e.g., using a steam oxidation process, causing the surplus silicon to form silicon oxide that expands. The expansion of the silicon oxide acts to exert a compressive stress on adjacent silicon, which has been shown to improve carrier mobility and thus transistor gain control. For one embodiment, the expansion is achieved when the silicon-rich oxide material 330 has a molar ratio of silicon to oxygen within a range of about 1:1 to about 2:1. For another embodiment, the ratio may be adjusted, dependent upon on the steam and temperature conditions used for the steam oxidation, in order to obtain a desired degree of expansion or resulting compressive stress.
In FIG. 2D , a portion of the fifth dielectric layer 230 is removed, such as by etching in an etch-back process, so that an upper surface of the fifth dielectric layer 230 is recessed within the respective trenches 210 , e.g., below an upper surface of substrate 200 , exposing a portion of the fourth dielectric layer 220 lining each of trenches 210 . For embodiments where fifth dielectric layer 230 is a polysilazane-based SOD material, the etch-back process for removing the portion of the fifth dielectric layer 230 includes using a mixture of deionized water and ammonium hydroxide, at a temperature in the range from about 20° C. to about 90° C., preferably at about 55° C. For other embodiments where the fifth dielectric layer 230 is spin-on dielectric (SOD) material, e.g., polysilazane, the fifth dielectric layer 230 is cured, e.g., using the steam-oxidation process, after the removal of the portion of the fifth dielectric layer 230 , i.e., is performed for the structure of FIG. 2D .
A portion of the fourth dielectric layer 220 is selectively removed in FIG. 2E , e.g., using a controlled wet etch, to a level of the upper surface of the fifth dielectric layer 230 such that a remaining portion of the fourth dielectric layer 220 is interposed between the fifth dielectric layer 230 and the third dielectric layer 212 . That is, the fourth dielectric layer 220 is removed from an upper surface of the mask layer 206 , and the exposed portion of the fourth dielectric layer 220 located within each of trenches 210 is removed. This exposes the upper surface of the mask layer 206 , the portions of the mask layer 206 , the conductive layer 204 , and the first dielectric layer 202 through which trenches 210 pass, and a portion of the third dielectric layer 212 lying between the upper surface of substrate 200 and the upper surface of the fifth dielectric layer. The remaining portions of the fourth dielectric layer 220 and the fifth dielectric layer 230 form a first dielectric plug 232 that fills a lower portion of trenches 210 , as shown in FIG. 2E , having an upper surface that is recessed below the upper surface of the substrate 200 . For another embodiment, the fourth dielectric layer 220 is removed to a level of an upper surface of the oxidized silicon-rich oxide material 330 of FIG. 3 to form a plug similar to first dielectric plug 232 (not shown in FIG. 3 ).
In FIG. 2F , a sixth dielectric layer 240 is blanket deposited over the structure of FIG. 2E and fills an unfilled portion of each of trenches 210 . Specifically, the sixth dielectric layer 240 is deposited on the exposed upper surface of the mask layer 206 , on the exposed portions of the mask layer 206 , the conductive layer 204 , and the first dielectric layer 202 through which trenches 210 pass, on the portion of the third dielectric layer 212 lying between the upper surface of substrate 200 and the upper surface of the fifth dielectric layer, and on the first dielectric plug 232 . For one embodiment, the sixth dielectric layer 240 is of a high-density-plasma (HDP) dielectric material, such as a high-density-plasma (HDP) oxide. Note that the first dielectric plugs 232 reduce the remaining depths of trenches 210 and thus their aspect ratios for the deposition of the sixth dielectric layer 240 . The reduced aspect ratios of trenches 210 act to reduce the formation of voids when depositing the sixth dielectric layer 240 within the unfilled portions of trenches 210 . For another embodiment, in a similar fashion, the sixth dielectric layer 240 is formed over the structure of FIG. 3 after the removal of the fourth dielectric layer 220 to the level of an upper surface of the oxidized silicon-rich oxide material 330 (not shown in FIG. 3 ).
A portion of the sixth dielectric layer 240 is removed from the structure of FIG. 2F in FIG. 2G , e.g., using chemical mechanical polishing (CMP). That is, the sixth dielectric layer 240 is removed so that the upper surface of the mask layer 206 is exposed and so that an upper surface of the sixth dielectric layer 240 within each of trenches 210 is substantially flush with the upper surface of the mask layer 206 . Note that the portion of the sixth dielectric layer 240 within each of the trenches 210 forms a second dielectric plug 242 that passes through the mask layer 206 , the conductive layer 204 , the first conductive layer 202 , extends into the substrate 200 , and terminates at the first conductive plug 232 . The third dielectric layer 212 is interposed between the portion of the second dielectric plug 242 and the substrate 200 and the first dielectric plug 232 and the substrate 200 . Note that a structure similar to that of FIG. 2H may be formed from the structure of FIG. 3 after the removal of the fourth dielectric layer 220 and the formation of sixth dielectric layer 240 , with the oxidized silicon-rich oxide material 330 replacing the fifth dielectric layer 230 .
Note that the fourth dielectric layer 220 is located in the lower portion of each of trenches 210 and thus away from the layers disposed on the upper surface of substrate 200 that can be used to form memory cells. This acts to reduce problems associated with the fourth dielectric layer 220 storing trapped charges, especially when the fourth dielectric layer 220 is of nitride, that can adversely affect the reliability of the memory cells and thus the memory device.
Mask 206 is subsequently removed to expose the conductive layer 204 . A seventh dielectric layer 250 , e.g., such as a layer of silicon oxide, a nitride, an oxynitride, an oxide-nitride-oxide (ONO) layer, etc., is then formed on the exposed conductive layer 204 . A conductive layer 260 , such as a doped polysilicon layer, a metal layer, e.g., refractory metal layer, a metal containing layer, e.g., a metal silicide layer, or the like, is formed on the seventh dielectric layer 250 , as shown in FIG. 2H . The conductive layer 260 may include one or more conductive materials or conductive layers, a metal or metal containing layer disposed on a polysilicon layer, etc. For another embodiment, conductive layers 204 and 260 respectively form a floating gate and a control gate (or word line) of memory cells of a memory array, such as memory array 104 of FIG. 1 , and the seventh dielectric layer 250 forms an intergate dielectric layer that separates the floating gate and the control gate. Source/drain regions are also formed in a portion of substrate 200 not shown in FIG. 2G as a part of the memory array. For one embodiment, conductive layer 204 is extended to improve the coupling of the floating gate. The trenches 210 filled with dielectric materials, as described above, act to prevent extraneous current flow through the substrate between the memory cells.
The components located in the region peripheral to memory array 104 of FIG. 1 (hereinafter the periphery) are also formed on the substrate 200 . For one embodiment the periphery may include address decoder 106 , row access circuitry 108 , column access circuitry 110 , control circuitry 112 , Input/Output (I/O) circuitry 114 , and address buffer 116 of memory device 102 , as shown in FIG. 1 . For another embodiment, the row access circuitry 108 and column access circuitry 110 may include high-voltage circuitry, such as high-voltage pumps. For some embodiments, the periphery includes passive elements, such as capacitors, and active elements, such as transistors, e.g., field-effect transistors.
For some embodiments, a memory array and a periphery are formed overlying the substrate 200 , as shown in FIGS. 4A through 4E at different stages of fabrication, according to another embodiment of the invention. The structure of FIG. 4A , for one embodiment, is formed essentially as described for FIGS. 2A-2B . That is, the first dielectric layer 202 , the conductive layer 204 , and the mask layer 206 are formed overlying substrate 200 ; trenches 210 are formed through the mask layer 206 , the conductive layer 204 , and the first dielectric layer 202 such that trenches 210 extend into substrate 200 ; the portion of trenches 210 extending into substrate 200 is lined with the third dielectric layer 212 ; and the fourth dielectric layer 220 is formed overlying the first dielectric layer 202 , the conductive layer 204 , the mask layer 206 , and the third dielectric layer 212 . For one embodiment, the trenches 210 in the periphery are deeper and/or wider than the trenches 210 in the array and thus have a larger volume than the trenches 210 in the array, as shown in FIG. 4A .
The fifth dielectric layer 230 is deposited overlying the structure of FIG. 4A in FIG. 4B so that dielectric material of the fifth dielectric layer 230 overfills trenches 210 . For the embodiment where the trenches 210 in the periphery have a larger volume than those in the array, more dielectric material is required to fill the trenches 210 of the periphery. Therefore, the trenches 210 of the array are filled more quickly than the trenches 210 of the periphery, and continued deposition of the dielectric material of the fifth dielectric layer 230 overfills the trenches 210 of the periphery. This, coupled with the fluid properties of the dielectric material, causes a step 410 to form in the fifth dielectric layer 230 between the array and the periphery, as shown in FIG. 4B . In FIG. 4C , a portion of the fifth dielectric layer 230 is removed, e.g., by CMP, so that step 410 is removed and an upper surface of the fifth dielectric layer 230 is substantially level, i.e., so that the upper surface of the fifth dielectric layer 230 in the periphery and the upper surface of the fifth dielectric layer 230 in the array are substantially co-planer. For one embodiment, the removal of the fifth dielectric layer 230 proceeds until an upper surface of the fifth dielectric layer 230 is substantially flush with an upper surface of the fourth dielectric layer 220 , as shown in FIG. 4C . For another embodiment, the removal proceeds until the fifth dielectric layer 230 is substantially level and overlies the upper surface of the fourth dielectric layer 220 (not shown).
In FIG. 4D , the fifth dielectric layer 230 is recessed within the respective trenches 210 , e.g., using an etch-back process, as described above in conjunction with FIG. 2D . Note further that leveling the fifth dielectric layer 230 prior to recessing the fifth dielectric layer 230 within the respective trenches 210 acts so that the fifth dielectric layer 230 is recessed to substantially the same level below the first dielectric layer 202 within the array and periphery trenches. Subsequently, for one embodiment, the process proceeds as described above for FIGS. 2E-2H to form the structure of FIG. 4E . That is, a portion of the fourth dielectric layer 220 is selectively removed to a level of the upper surface of the fifth dielectric layer 230 ; the sixth dielectric layer 240 is formed to fill the remaining portion of the trenches 210 ; the hard mask layer 206 is removed; and the seventh dielectric layer 250 and the conductive layer 260 are formed overlying conductive layer 204 .
In the array, the gate stacks comprising first dielectric layer 202 , the conductive layer 204 , the seventh dielectric layer 250 , and the conductive layer 260 each form a floating-gate transistor 275 that acts as a memory cell of the array. Each of the gate stacks comprising first dielectric layer 202 , the conductive layer 204 , the seventh dielectric layer 250 , and the conductive layer 260 in the periphery forms a field-effect transistor 280 . For some embodiments, the conductive layer 204 and the conductive layer 260 of each field-effect transistor 280 may be strapped (or shorted) together so that the shorted together conductive layers form the control gate of that field-effect transistor 280 . For another embodiment, the conductive layers 204 and 260 are not shorted together, and the conductive layer 204 forms the control gate of the field-effect transistors 280 . Note that field-effect transistors 280 , for one embodiment, form a portion of the logic of row access circuitry 108 and/or column access circuitry 110 of the memory device 102 of FIG. 1 for accessing rows and columns of the memory array 104 .
CONCLUSION
Although specific embodiments have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement that is calculated to achieve the same purpose may be substituted for the specific embodiments shown. Many adaptations of the invention will be apparent to those of ordinary skill in the art. Accordingly, this application is intended to cover any adaptations or variations of the invention. It is manifestly intended that this invention be limited only by the following claims and equivalents thereof. | A method includes removing a portion of a substrate to define an isolation trench; forming a first dielectric layer on exposed surfaces of the substrate in the trench; forming a second dielectric layer on at least the first dielectric layer, the second dielectric layer containing a different dielectric material than the first dielectric layer; depositing a third dielectric layer to fill the trench; removing an upper portion of the third dielectric layer from the trench and leaving a lower portion covering a portion of the second dielectric layer; oxidizing the lower portion of the third dielectric layer after removing the upper portion; removing an exposed portion of the second dielectric layer from the trench, thereby exposing a portion of the first dielectric layer; and forming a fourth dielectric layer in the trench covering the exposed portion of the first dielectric layer. | 30,077 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims the benefit of U.S. Provisional Application No. 60/985,533, filed on Nov. 5, 2007. The disclosure of the above application is incorporated herein by reference.
FIELD
The present disclosure relates to torque estimation and control, and more particularly to coordinating cylinder fueling and spark timing in torque estimation and control.
BACKGROUND
The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the presently named inventors, to the extent it is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted as prior art against the present disclosure.
Torque model data is often gathered on a dynamometer with all cylinders of an engine being fueled. However, some engines now use partial cylinder deactivation to reduce pumping losses and increase fuel economy. For example, four cylinders out of an eight cylinder engine may be deactivated to reduce pumping losses. In addition, some engines may deactivate all cylinders of the engine during deceleration, which reduces fuel usage. In addition, the pumping losses and rubbing friction of the engine with all cylinders deactivated may create a negative torque (braking torque) that helps to slow the vehicle. To accommodate these types of engines, adjustments may be made for torque estimation and control to account for the number of cylinders that are actually being fueled.
The torque produced by the activated (fueled) cylinders may be referred to as indicated torque or cylinder torque. Flywheel torque may be determined by subtracting rubbing friction, pumping losses, and accessory loads from the indicated torque. Therefore, in one approach to estimating torque with partial cylinder deactivation, the indicated torque is multiplied by a fraction of cylinders being fueled to determine a fractional indicated torque. The fraction is the number of cylinders being fueled divided by the total number of cylinders. Rubbing friction, pumping losses, and accessory loads can be subtracted from the fractional indicated torque to estimate an average torque at the flywheel (brake torque) for partial cylinder deactivation.
SUMMARY
An engine control system comprises a torque control module and a fueling control module. The torque control module selectively generates a deactivation signal for a first cylinder of a plurality of cylinders of an engine based on a torque request. The fueling control module halts fuel delivery to the first cylinder based on the deactivation signal. The torque control module increases a spark advance of the engine at a first time after the fueling control module halts fuel injection for the first cylinder. The first time corresponds to an initial time combustion fails to occur in the first cylinder because fuel delivery has been halted.
Further areas of applicability of the present disclosure will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples are intended for purposes of illustration only and are not intended to limit the scope of the disclosure.
BRIEF DESCRIPTION OF THE DRAWINGS
The present disclosure will become more fully understood from the detailed description and the accompanying drawings, wherein:
FIG. 1 is a graphical depiction of a decreasing torque request and corresponding cylinder deactivation and spark advance for an exemplary 4-cylinder engine;
FIG. 2 is a graphical depiction of cylinder event timing in an exemplary V8 engine;
FIG. 3 is a functional block diagram of an exemplary engine system;
FIG. 4 is a functional block diagram of an exemplary engine control system;
FIG. 5 is a functional block diagram of elements of the exemplary engine control system of FIG. 4 ; and
FIG. 6 is a flowchart that depicts exemplary steps performed by the elements shown in FIG. 5 to coordinate cylinder deactivation and spark advance.
DETAILED DESCRIPTION
The following description is merely exemplary in nature and is in no way intended to limit the disclosure, its application, or uses. For purposes of clarity, the same reference numbers will be used in the drawings to identify similar elements. As used herein, the phrase at least one of A, B, and C should be construed to mean a logical (A or B or C), using a non-exclusive logical or. It should be understood that steps within a method may be executed in different order without altering the principles of the present disclosure.
As used herein, the term module refers to an Application Specific Integrated Circuit (ASIC), an electronic circuit, a processor (shared, dedicated, or group) and memory that execute one or more software or firmware programs, a combinational logic circuit, and/or other suitable components that provide the described functionality.
In an internal combustion engine, fuel and spark are relatively fast actuators. The term fast is used in contrast to air flow (which may be measured as air per cylinder), which changes slowly as the throttle valve opens or closes. Removing fuel from one or more cylinders (deactivating the cylinders) and decreasing (retarding) the spark advance can both be used to achieve fast changes in brake torque.
When controlling an internal combustion engine, a rapid transition to minimum torque may be requested. The minimum torque the engine can produce with all cylinders on is limited by the minimum amount of air flow needed to maintain adequate combustion in all cylinders. To reduce the torque of the engine even further, cylinders are deactivated.
A minimum torque request may be made when the vehicle is decelerating, such as when the driver has removed their foot from the accelerator pedal. Minimum torque may be especially helpful for engine braking when traveling on downgrades. A smooth transition to minimum engine off torque can also be used when shutting down the engine, such as in a hybrid application. For example, in a hybrid application, the engine may be powered down when the vehicle comes to a stop. Rapid torque reductions may also be used to prevent engine flare when the clutch pedal of a manual transmission is depressed.
Cylinders can be individually turned off for a step-wise reduction in torque. However, abrupt changes in torque may be transmitted through the frame and perceived as a noise, vibration, or harshness issue. To create a smooth torque ramp, cylinder deactivation can be combined with changes in spark advance to produce a smooth torque reduction without points of discontinuity. In order to achieve this smooth response, spark advance is closely synchronized with cylinder deactivation.
Instead of experiencing an abrupt torque reduction when a cylinder is deactivated, the ignition system can advance the spark at the same time that the cylinder is deactivated. The increased spark advance offsets the torque reduction from the cylinder deactivation. The spark advance can then be ramped to a lower value.
At this time, the next cylinder can be turned off, with another corresponding increase in spark advance. This can be repeated for each cylinder, with the spark advance smoothing the transitions when cylinders are deactivated. A similar scheme can be used for smoothing increasing torque as cylinders are reactivated. For example, this may be used when the internal combustion engine in a hybrid application is restarted or when a driver once again depresses the accelerator pedal on a downgrade.
An example of a strategy where spark advance offsets large decreases in torque from cylinder deactivation is shown in FIG. 1 . FIG. 1 also depicts the difference between when a cylinder is commanded to be deactivated and when the cylinder actually is deactivated. Because of the close coupling between cylinder deactivation and spark advance, FIG. 1 shows how spark advance is affected by the delay in actual cylinder deactivation.
In addition to the coordination between spark advance and cylinder deactivation for torque control, coordination is also useful for torque estimation. Torque estimation is used to control engine parameters, and may be used by a hybrid controller to determine current or future torque requested from an electric motor. If the torque estimation function receives notice of a cylinder being deactivated without receiving notice of the corresponding increase in spark advance, torque estimation may erroneously estimate a negative spike in torque.
Therefore, when control is able to provide cylinder deactivation information at the same time as the corresponding spark advance, torque estimation may be able to incorporate the combined effects of both changes. FIG. 2 shows an exemplary cylinder firing diagram for a V8 engine, which illustrates why there may be a delay between a cylinder deactivation command and actual cylinder deactivation.
FIG. 3 depicts an engine system where fuel control is coordinated with spark control. FIG. 4 depicts exemplary components of an engine control module of the engine system. FIG. 5 depicts in greater detail certain components that are used to coordinate fueling and spark advance for the exemplary engine system. FIG. 6 depicts exemplary control steps used in determining and applying coordinated fueling and spark advance parameters.
Referring now to FIG. 1 , a graphical depiction of a decreasing torque request, cylinder deactivation, and spark advance for an exemplary 4-cylinder engine is presented. The torque request begins at a minimum air torque, which is −10 Nm in this example. The minimum air torque represents the torque produced when all cylinders are fueled and the minimum amount of air for proper combustion is provided to the cylinders.
The torque ramp then decreases until the minimum engine off torque is reached, which is −30 Nm in this example. At the minimum engine off torque, no fuel is provided to the cylinders and therefore no torque is being generated. Negative torque is created by friction in the engine, and may also be created by pumping losses resulting from the pistons drawing in, compressing, and expelling air.
Also indicated are the approximate average torques of the engine with 3, 2, and 1 cylinders activated, which are −15 Nm, −20 Nm and −25 Nm, respectively. At time t 1 , the number of cylinders is instructed to reduce from four to three. After a delay 10 , the number of cylinders actually activated decreases from four to three.
At time t 2 , the number of cylinders instructed to be activated is decreased from three to two. After a delay 20 , the actual number of cylinders activated decreases from three to two. As seen in FIG. 1 , delays, such as delay 10 and delay 20 , are not necessarily equal. This will be explained below with respect to FIG. 2 .
FIG. 1 also shows an uncoordinated spark advance, where the spark advance is set based upon the instructed number of activated cylinders. Therefore, at time t 1 , the uncoordinated spark advance increases to offset the decrease in torque caused by the cylinder reduction. However, because the cylinder was not actually deactivated until after the delay 10 , the increase in the uncoordinated spark advance would cause a spike in engine torque. The spark advance then ramps to a minimum level, where the next cylinder can be deactivated. The minimum level may represent the lowest spark advance that will still result in stable combustion.
A coordinated spark advance is shown, which increases spark advance at times when the number of cylinders being fueled actually decreases. A graph of torque estimation (not shown) based on coordinated spark and fuel control will be fairly smooth. This is because torque estimation receives the decreased number of cylinders as spark control provides torque estimation with the newly updated spark advance. By contrast, a graph of torque estimation (also not shown) corresponding to the uncoordinated spark advance would have downward torque spikes as each cylinder was deactivated.
Referring now to FIG. 2 , a graphical depiction of cylinder event timing in an exemplary V8 engine is presented. At the top of FIG. 2 is a square wave indicating teeth on a crankshaft wheel. The X axis represents crankshaft angle, and is shown between 0 and 720 degrees because cylinders fire every two crankshaft revolutions. The 8 cylinders are labeled with letters, from A to H. There are two gaps shown in the crankshaft teeth, one at top dead center (TDC) of cylinder D, and one at TDC of cylinder H. These gaps may be used for synchronizing the crankshaft signal. The time when the piston is at its topmost position, which is the point at which the air/fuel mixture is most compressed, is referred to as TDC.
A portion of the crankshaft period on the right of FIG. 2 is repeated on the left of FIG. 2 . This explains why TDC of cylinder H appears at both the left and the right. Ignition timing control may occur at a defined time for each cylinder. For example only, these events may be defined at 72° or 73.5° before TDC of each cylinder.
Timelines of the four strokes (intake, compression, power and exhaust) are shown for each cylinder. The cylinders are arranged in firing order from top to bottom, A to H. The physical cylinder number is indicated at the left of each timeline.
The end of the intake stroke for a cylinder may be defined as the time when the corresponding intake valve closes. The fuel boundary represents the last time at which fuel released from the fuel injectors will make it into the combustion chamber in that intake stroke. Normally, this will be slightly before the end of the intake stroke. For applications where fuel is injected directly into the combustion chamber, the fuel boundary may be at or after the end of the intake stroke.
After the fuel boundary, the fuel injector corresponding to the cylinder can begin spraying fuel for the next intake stroke. The fuel injector may spray fuel during the exhaust stroke so that a fuel-air mixture will be ready when the intake valve opens. Fuel may be sprayed earlier, such as in the compression or power strokes, to allow for more mixing of air and fuel and/or to allow for more time in which to inject a greater amount of fuel.
Because of the long period during which fuel may be sprayed, deactivating fuel to a cylinder may be done at the fuel boundaries. Therefore, when a request to deactivate cylinder 1 is received, the fuel injector for cylinder 1 is not deactivated until the next fuel boundary is reached. If the request is received slightly after a fuel boundary, nearly two crankshaft revolutions will occur before the fuel boundary is again reached.
Even after the fuel injector is disabled following the fuel boundary, the combustion chamber will already contain the previously sprayed fuel. The compression, power, and exhaust strokes therefore operate with the fuel that was previously injected. When the next intake stroke is reached, there is little or no fuel, as the fuel injector has been disabled for the last four strokes.
At this point, the combustion chamber contains only air. The compression stroke then compresses the air in the cylinder, and during the power stroke, no fuel-air mixture is present to ignite. This is the time at which the reduced torque from deactivating the cylinder is actually realized.
As seen in the example timing diagram of FIG. 2 , cylinder 8 fires before cylinder 1 would have fired, while cylinder 2 fires after cylinder 1 would have fired. The spark can be advanced starting with either the firing of cylinder 8 or the firing of cylinder 2 . In four-cylinder applications, there may not be enough time to advance the spark for the cylinder firing before cylinder 1 . In such cases, the spark will be advanced for the cylinder firing after cylinder 1 .
The spark advance can then be gradually reduced by following the torque command through the use of a torque model until the next cylinder is deactivated. The variable delay in FIG. 1 can now be understood. If a cylinder deactivation request is received immediately after the fuel boundary for that cylinder, two crankshaft revolutions will pass before the fuel injector for that cylinder can be disabled. In the next two crankshaft revolutions, the fuel previously sprayed is combusted and exhausted. The following intake and compression strokes operate on air that does not have injected fuel. At the power stroke, one crankshaft revolution after the intake stroke, there is no air/fuel mixture to ignite, and the average torque of the engine is therefore reduced.
On the other hand, if a cylinder deactivation request is received immediately before a fuel boundary, when the fuel boundary is reached, the fuel injector for that cylinder will be disabled. Then, after two crankshaft revolutions, the intake stroke draws in air, and after one more crankshaft revolution, the air mixture is not ignited. Therefore, the variable delay shown in FIG. 1 may vary between three and five crankshaft revolutions.
Referring now to FIG. 3 , a functional block diagram of an exemplary engine system 100 is presented. The engine system 100 includes an engine 102 that combusts an air/fuel mixture to produce drive torque for a vehicle based on a driver input module 104 . Air is drawn into an intake manifold 110 through a throttle valve 112 . An engine control module (ECM) 114 commands a throttle actuator module 116 to regulate opening of the throttle valve 112 to control the amount of air drawn into the intake manifold 110 .
Air from the intake manifold 110 is drawn into cylinders of the engine 102 . While the engine 102 may include multiple cylinders, for illustration purposes, a single representative cylinder 118 is shown. For example only, the engine 102 may include 2, 3, 4, 5, 6, 8, 10, and/or 12 cylinders. The ECM 114 may instruct a cylinder actuator module 120 to selectively deactivate some of the cylinders to improve fuel economy.
Air from the intake manifold 110 is drawn into the cylinder 118 through an intake valve 122 . The ECM 114 controls the amount of fuel injected by a fuel injection system 124 to achieve a desired air/fuel ratio. The fuel injection system 124 may inject fuel into the intake manifold 110 at a central location or may inject fuel into the intake manifold 110 at multiple locations, such as near the intake valve of each of the cylinders. Alternatively, the fuel injection system 124 may inject fuel directly into the cylinders. The cylinder actuator module 120 may control to which cylinders the fuel injection system 124 injects fuel.
The injected fuel mixes with the air and creates the air/fuel mixture in the cylinder 118 . A piston (not shown) within the cylinder 118 compresses the air/fuel mixture. Based upon a signal from the ECM 114 , a spark actuator module 126 energizes a spark plug 128 in the cylinder 118 , which ignites the air/fuel mixture. The timing of the spark may be specified relative to TDC.
The combustion of the air/fuel mixture drives the piston down, thereby driving a rotating crankshaft (not shown). The piston then begins moving up again and expels the byproducts of combustion through an exhaust valve 130 . The byproducts of combustion are exhausted from the vehicle via an exhaust system 134 .
The intake valve 122 may be controlled by an intake camshaft 140 , while the exhaust valve 130 may be controlled by an exhaust camshaft 142 . In various implementations, multiple intake camshafts may control multiple intake valves per cylinder and/or may control the intake valves of multiple banks of cylinders. Similarly, multiple exhaust camshafts may control multiple exhaust valves per cylinder and/or may control exhaust valves for multiple banks of cylinders. The cylinder actuator module 120 may deactivate cylinders by halting provision of fuel and spark and/or disabling their exhaust and/or intake valves.
The time at which the intake valve 122 is opened may be varied with respect to piston TDC by an intake cam phaser 148 . The time at which the exhaust valve 130 is opened may be varied with respect to piston TDC by an exhaust cam phaser 150 . A phaser actuator module 158 controls the intake cam phaser 148 and the exhaust cam phaser 150 based on signals from the ECM 114 .
The engine system 100 may include a boost device that provides pressurized air to the intake manifold 110 . For example, FIG. 1 depicts a turbocharger 160 . The turbocharger 160 is powered by exhaust gases flowing through the exhaust system 134 , and provides a compressed air charge to the intake manifold 110 . The turbocharger 160 may compress air before the air reaches the intake manifold 110 .
A wastegate 164 may allow exhaust gas to bypass the turbocharger 160 , thereby reducing the turbocharger's output (or boost). The ECM 114 controls the turbocharger 160 via a boost actuator module 162 . The boost actuator module 162 may modulate the boost of the turbocharger 160 by controlling the position of the wastegate 164 .
An intercooler (not shown) may dissipate some of the compressed air charge's heat, which is generated by air being compressed and may by the air's proximity to the exhaust system 134 . Alternate engine systems may include a supercharger that provides compressed air to the intake manifold 110 and is driven by the crankshaft.
The engine system 100 may include an exhaust gas recirculation (EGR) valve 170 , which selectively redirects exhaust gas back to the intake manifold 110 . In various implementations, the EGR valve 170 may be located after the turbocharger 160 . The engine system 100 may measure the speed of the crankshaft in revolutions per minute (RPM) using an RPM sensor 180 . The temperature of the engine coolant may be measured using an engine coolant temperature (ECT) sensor 182 . The ECT sensor 182 may be located within the engine 102 or at other locations where the coolant is circulated, such as a radiator (not shown).
The pressure within the intake manifold 110 may be measured using a manifold absolute pressure (MAP) sensor 184 . In various implementations, engine vacuum, which is the difference between ambient air pressure and the pressure within the intake manifold 110 , may be measured. The mass of air flowing into the intake manifold 110 may be measured using a mass air flow (MAF) sensor 186 . In various implementations, the MAF sensor 186 may be located in a housing with the throttle valve 112 .
The throttle actuator module 116 may monitor the position of the throttle valve 112 using one or more throttle position sensors (TPS) 190 . The ambient temperature of air being drawn into the engine system 100 may be measured using an intake air temperature (IAT) sensor 192 . The ECM 114 may use signals from the sensors to make control decisions for the engine system 100 .
The ECM 114 may communicate with a transmission control module 194 to coordinate shifting gears in a transmission (not shown). For example, the ECM 114 may reduce torque during a gear shift. The ECM 114 may communicate with a hybrid control module 196 to coordinate operation of the engine 102 and an electric motor 198 . The electric motor 198 may also function as a generator, and may be used to produce electrical energy for use by vehicle electrical systems and/or for storage in a battery. In various implementations, the ECM 114 , the transmission control module 194 , and the hybrid control module 196 may be integrated into one or more modules.
To abstractly refer to the various control mechanisms of the engine 102 , each system that varies an engine parameter may be referred to as an actuator. For example, the throttle actuator module 116 can change the blade position, and therefore the opening area, of the throttle valve 112 . The throttle actuator module 116 can therefore be referred to as an actuator, and the throttle opening area can be referred to as an actuator position or actuator value.
Similarly, the spark actuator module 126 can be referred to as an actuator, while the corresponding actuator position may be the amount of spark advance. Other actuators may include the boost actuator module 162 , the EGR valve 170 , the phaser actuator module 158 , the fuel injection system 124 , and the cylinder actuator module 120 . The term actuator position with respect to these actuators may correspond to boost pressure, EGR valve opening, intake and exhaust cam phaser angles, air/fuel ratio, and number of cylinders activated, respectively.
Referring now to FIG. 4 , a functional block diagram of an exemplary engine control system is presented. An engine control module (ECM) 300 includes an axle torque arbitration module 304 . The axle torque arbitration module 304 arbitrates between driver inputs from the driver input module 104 and other axle torque requests. For example, driver inputs may include accelerator pedal position.
Other axle torque requests may include a torque reduction requested during wheel slip by a traction control system and torque requests to control speed from a cruise control system. Torque requests may include target torque values as well as ramp requests, such as a request to ramp torque down to the minimum engine off torque or ramp torque up from the minimum engine off torque.
Axle torque requests may also include requests from an adaptive cruise control module, which may vary a torque request to maintain a predetermined following distance. Axle torque requests may also include torque increases due to negative wheel slip, such as where a tire of the vehicle slips with respect to the road surface when the torque produced by the engine is negative.
Axle torque requests may also include brake torque management requests and torque requests intended to prevent vehicle over-speed conditions. Brake torque management requests may reduce engine torque to ensure that engine torque does not exceed the ability of the brakes to hold the vehicle when the vehicle is stopped. Axle torque requests may also be made by body stability control systems. Axle torque requests may further include engine cutoff requests, such as may be generated when a critical fault is detected.
The axle torque arbitration module 304 outputs a predicted torque and an immediate torque. The predicted torque is the amount of torque that will be required in the future to meet the driver's torque request and/or speed requests. The immediate torque is the amount of currently required to meet temporary torque requests, such as torque reductions when shifting gears or when traction control senses wheel slippage.
The immediate torque may be achieved by engine actuators that respond quickly, while slower engine actuators may be targeted to achieve the predicted torque. For example, a spark actuator may be able to quickly change spark advance, while cam phaser or throttle actuators may be slower to respond because of air transport delays in the intake manifold. The axle torque arbitration module 304 outputs the predicted torque and the immediate torque to a propulsion torque arbitration module 308 .
In various implementations, the axle torque arbitration module 304 may output the predicted torque and immediate torque to a hybrid optimization module 312 . The hybrid optimization module 312 determines how much torque should be produced by the engine and how much torque should be produced by the electric motor 198 . The hybrid optimization module 312 then outputs modified predicted and immediate torque values to the propulsion torque arbitration module 308 . In various implementations, the hybrid optimization module 312 may be implemented in the hybrid control module 196 of FIG. 1 .
The predicted and immediate torques received by the propulsion torque arbitration module 308 are converted from the axle torque domain (at the wheels) into the propulsion torque domain (at the crankshaft). This conversion may occur before, after, or in place of the hybrid optimization module 312 .
The propulsion torque arbitration module 308 arbitrates between the converted predicted and immediate torque and other propulsion torque requests. Propulsion torque requests may include torque reductions for engine over-speed protection, torque increases for stall prevention, and torque reductions requested by the transmission control module 194 to accommodate gear shifts. Propulsion torque requests may also include torque requests from a speed control module, which may control engine speed during idle and coastdown, such as when the driver removes their foot from the accelerator pedal.
Propulsion torque requests may also include a clutch fuel cutoff, which may reduce engine torque when the driver depresses the clutch pedal in a manual transmission vehicle. Various torque reserves may also be provided to the propulsion torque arbitration module 306 to allow for fast realization of those torque values should they be needed. For example, a reserve may be applied to allow for air conditioning compressor turn-on and/or for power steering pump torque demands.
A catalyst light-off or cold start emissions process may directly vary spark advance for an engine. A corresponding propulsion torque request may be made to balance out the change in spark advance. In addition, the air-fuel ratio of the engine and/or the mass air flow of the engine may be varied, such as by diagnostic intrusive equivalence ratio testing and/or new engine purging. Corresponding propulsion torque requests may be made to offset these changes.
Propulsion torque requests may also include a shutoff request, which may be initiated by detection of a critical fault. For example, critical faults may include vehicle theft detection, stuck starter motor detection, electronic throttle control problems, and unexpected torque increases. In various implementations, various requests, such as shutoff requests, may not be arbitrated. For example only, shutoff requests may always win arbitration or may override arbitration altogether. The propulsion torque arbitration module 306 may still receive these requests so that, for example, appropriate data can be fed back to other torque requesters. For example, all other torque requestors may be informed that they have lost arbitration.
An actuation mode module 314 receives the predicted torque and the immediate torque from the propulsion torque arbitration module 306 . Based upon a mode setting, the actuation mode module 314 determines how the predicted and immediate torques will be achieved. For example, changing the throttle valve 112 allows for a wide range of torque control. However, opening and closing the throttle valve 112 is relatively slow.
Disabling cylinders provides for a wide range of torque control, but may produce drivability and emissions concerns. Changing spark advance is relatively fast, but does not provide much range of control. In addition, the amount of control possible with spark (spark capacity) changes as the amount of air entering the cylinder 118 changes.
According to the present disclosure, the throttle valve 112 may be closed just enough so that the desired immediate torque can be achieved by retarding the spark as far as possible. This provides for rapid resumption of the previous torque, as the spark can be quickly returned to its calibrated timing. In this way, the use of relatively slowly-responding throttle valve corrections is minimized by using the quickly-responding spark retard as much as possible.
The approach the actuation mode module 314 takes in meeting the immediate torque request is determined by a mode setting. The mode setting provided to the actuation mode module 314 may include an indication of modes including an inactive mode, a pleasible mode, a maximum range mode, and an auto actuation mode.
In the inactive mode, the actuation mode module 314 may ignore the immediate torque request. For example, the actuation mode module 314 may output the predicted torque to a predicted torque control module 316 . The predicted torque control module 316 converts the predicted torque to desired actuator positions for slow actuators. For example, the predicted torque control module 316 may control desired manifold absolute pressure (MAP), desired throttle area, and/or desired air per cylinder (APC).
An immediate torque control module 320 determines desired actuator positions for fast actuators, such as desired spark advance. The actuation mode module 314 may instruct the immediate torque control module 320 to set the spark advance to a calibrated value, which achieves the maximum possible torque for a given airflow. In the inactive mode, the immediate torque request does not therefore reduce the amount of torque produced or cause the spark advance to deviate from calibrated values.
In the pleasible mode, the actuation mode module 314 may attempt to achieve the immediate torque request using only spark retard. This may mean that if the desired torque reduction is greater than the spark reserve capacity (amount of torque reduction achievable by spark retard), the torque reduction will not be achieved. The actuation mode module 314 may therefore output the predicted torque to the predicted torque control module 316 for conversion to a desired throttle area. The actuation mode module 314 may output the immediate torque request to the immediate torque control module 320 , which will retard the spark as much as possible to attempt to achieve the immediate torque.
In the maximum range mode, the actuation mode module 314 may instruct the cylinder actuator module 120 to turn off one or more cylinders to achieve the immediate torque request. The actuation mode module 314 may use spark retard for the remainder of the torque reduction by outputting the immediate torque request to the immediate torque control module 320 . If there is not enough spark reserve capacity, the actuation mode module 314 may reduce the predicted torque request going to the predicted torque control module 316 .
In the auto actuation mode, the actuation mode module 314 may decrease the predicted torque request output to the predicted torque control module 316 . The predicted torque may be reduced only so far as is necessary to allow the immediate torque control module 320 to achieve the immediate torque request using spark retard.
The immediate torque control module 320 receives an estimated torque from a torque estimation module 324 and sets spark advance using the spark actuator module 126 to achieve the desired immediate torque. The estimated torque may represent the amount of torque that could immediately be produced by setting the spark advance to a calibrated value.
When the spark advance is set to the calibrated value, the resulting torque (maintaining the current APC) may be as close to mean best torque (MBT) as possible. MBT refers to the maximum torque that is generated for a given APC as spark advance is increased while using high-octane fuel. The spark advance at which this maximum torque occurs may be referred to as MBT spark. The torque at the calibrated value may be less than the torque at MBT spark because of, for example, fuel quality and environmental factors.
The immediate torque control module 320 can demand a smaller spark advance than the calibrated spark advance in order to reduce the estimated torque of the engine to the immediate torque request. The immediate torque control module 320 may also decrease the number of cylinders activated via the cylinder actuation module 120 . The cylinder actuator module 120 then reports the actual number of activated cylinders to the immediate torque control module 320 and the torque estimation module 324 .
When the number of activated cylinders changes, the cylinder actuator module 120 may report this change to the immediate torque control module 320 before reporting the change to the torque estimation module 324 . In this way, the torque estimation module 324 receives the changed number of cylinders at the same time as the updated spark advance from the immediate torque control module 320 . The torque estimation module may estimate an actual torque that is currently being generated at the current APC and the current spark advance.
The predicted torque control module 316 receives the estimated torque and may also receive a measured mass air flow (MAF) signal and an engine speed signal, referred to as a revolutions per minute (RPM) signal. The predicted torque control module 316 may generate a desired manifold absolute pressure (MAP) signal, which is output to a boost scheduling module 328 . The boost scheduling module 328 uses the desired MAP signal to control the boost actuator module 162 . The boost actuator module 162 then controls a turbocharger or a supercharger.
The predicted torque control module 316 may generate a desired area signal, which is output to the throttle actuator module 116 . The throttle actuator module 116 then regulates the throttle valve 112 to produce the desired throttle area. The predicted torque control module 316 may use the estimated torque and/or the MAF signal in order to perform closed loop control, such as closed loop control of the desired area signal.
The predicted torque control module 316 may also generate a desired air per cylinder (APC) signal, which is output to a phaser scheduling module 332 . Based on the desired APC signal and the RPM signal, the phaser scheduling module 332 commands the intake and/or exhaust cam phasers 148 and 150 to calibrated values using the phaser actuator module 158 .
The torque estimation module 324 may use current intake and exhaust cam phaser angles along with the MAF signal to determine the estimated torque. The current intake and exhaust cam phaser angles may be measured values. Further discussion of torque estimation can be found in commonly assigned U.S. Pat. No. 6,704,638 entitled “Torque Estimator for Engine RPM and Torque Control,” the disclosure of which is incorporated herein by reference in its entirety.
Referring now to FIG. 5 , a functional block diagram of selected elements of the exemplary engine control system of FIG. 4 is presented. A torque ramp module 402 provides a ramping axle torque request to the axle torque arbitration module 304 of the ECM 300 .
The torque ramp module 402 may request an increasing or decreasing torque ramp from the axle torque arbitration module 304 . For example only, this torque ramp may be in response to the driver removing their foot from the accelerator pedal or a hybrid engine controller instructing the engine to shut down, for example.
The immediate torque control module 320 receives an immediate torque request via the hybrid optimization module 312 , propulsion torque arbitration module 308 , and the actuation mode module 314 . The immediate torque request may include the torque ramp from the axle torque arbitration module 304 .
The immediate torque control module 320 produces a desired spark advance for the spark actuator module 126 based on the number of cylinders that are activated. The immediate torque control module 320 also outputs the desired number of activated cylinders to the cylinder actuator module 120 .
The cylinder actuator module 120 includes a fueling control module 410 , a firing sequence dectection module 412 , and a cylinder power determination module 414 . The fueling control module 410 instructs the fuel injection system 124 as to which cylinders should receive fuel. The firing sequence detection module 412 determines which of the four strokes each cylinder is currently performing, which may be determined from a number of degrees of rotation of the crankshaft of the engine.
The firing sequence detection module 412 may receive a signal for each degree of rotation of the crankshaft or after every predetermined number of degrees of the crankshaft. The firing sequence detection module 412 may also receive signals indicating the angular position of the crankshaft after a larger number of degrees of rotation. For example only, the firing sequence detection module 412 may receive a signal at each cylinder firing event. For example only, in a V8, cylinder firing events may occur every 90 degrees of crankshaft rotation.
The firing sequence detection module 412 outputs cylinder event information to the fueling control module 410 and to the cylinder power determination module 414 . When the fueling control module 410 receives a decreased desired number of cylinders from the immediate torque control module 320 , the fueling control module 410 waits for the next fuel boundary.
The fueling control module 410 may deactivate a predetermined cylinder, or may deactivate the cylinder whose fuel boundary next occurs. Once the fuel boundary occurs, the fueling control module 410 instructs the fuel injection system 124 to stop providing fuel to that cylinder. The fueling control module 410 informs the cylinder power determination module 414 when each cylinder is deactivated.
The fueling control module 410 may wait until the next intake cycle of the recently deactivated cylinder before indicating to the cylinder power determination module 414 that fueling of the cylinder has been stopped. The cylinder power determination module 414 outputs the number of activated cylinders to the immediate torque control module 320 .
The cylinder power determination module 414 may wait to output the reduced number of activated cylinders until it is time to determine a new spark advance. This new spark advance is generated to offset the reduction in torque realized at the time the now-deactivated cylinder fails to fire. For example, the new spark advance may be used for the cylinder that fires before or the cylinder that fires after the now-deactivated cylinder.
The cylinder power determination module 414 may send the reduced number of activated cylinders to the torque estimation module 324 after or when the new spark advance is generated. In this way, the torque estimation module 324 receives the reduced number of activated cylinders along with the corresponding increased spark advance. This may prevent the torque estimation module 324 from estimating a torque glitch, where an abrupt drop in torque caused by the cylinder deactivation is then offset by an increased spark advance. The estimated torque may be provided to the immediate torque control module 320 and to other modules, such as the hybrid optimization module 312 shown in FIG. 4 .
Referring now to FIG. 6 , a flowchart depicts exemplary steps performed by the elements shown in FIG. 5 to coordinate cylinder deactivation and spark advance. When a decreasing torque ramp to engine off minimum torque is requested by the torque ramp module 402 and received by the immediate torque control module 320 , control begins in step 502 .
In step 502 , control initializes a variable NumCylinders to the total number of cylinders in the engine. Control continues in step 504 , where NumCylinders is reported to spark control (the immediate torque control module 320 ) and torque estimation (the torque estimation module 324 ). Control continues in step 506 , where control determines whether NumCylinders is equal to zero. If so, all cylinders are off and control ends; otherwise, control continues in step 507 .
In step 507 , control ramps the spark advance to a minimum value. For example only, the minimum value may be the minimum spark advance available where stable combustion is maintained. In step 508 , control instructs cylinder X to be deactivated. Cylinder X, which is the next cylinder to be deactivated, may be chosen so that cylinders with adjacent firing times are not deactivated consecutively. For example, in the V8 timing diagram of FIG. 2 , cylinders 3 or 4 may be deactivated after cylinder 1 . Deactivating cylinder 2 after cylinder 1 may result in added vibration, as six cylinders will fire followed by a gap where two cylinders do not fire.
Control continues in step 510 , where control waits until the fuel boundary of Cylinder X is reached. As described in FIG. 2 , this may require up to two crankshaft revolutions. Control continues in step 512 , where fuel is disabled for Cylinder X. Control continues in step 514 , where control waits for two crankshaft revolutions. At this point, cylinder X has finished an intake stroke where no fuel was sprayed.
Control then continues in step 516 , where NumCylinders is decremented. Control then continues in step 518 , where NumCylinders is reported to spark control. Control continues in step 520 , where spark control advances the spark for a cylinder that fires adjacently to when cylinder X would have fired if it contained an air-fuel mixture. This adjacent cylinder may be the cylinder that would fire immediately before cylinder X or the cylinder that would fire immediately after cylinder X.
The spark will remain advanced for future cylinder firing, although the spark advance will decrease to continue the decrease in torque ramp. The spark advance of step 520 may be an abrupt, discontinuous jump, while the spark advance otherwise follows a continuous downward contour that follows the downward ramp of the torque request. Control continues in step 522 , where NumCylinders is reported to torque estimation. Torque estimation will now have received the advance spark timing, which combined with the reduced NumCylinders, will allow the torque estimation to accurately estimate engine torque. Control then returns to step 506 .
When only a single cylinder change in deactivation is requested, steps 508 to 522 may be performed, without placing them in a loop that deactivates all cylinders. The steps of FIG. 6 can be easily adapted to achieve an increasing torque ramp. In such a case, the spark advance would be reduced as a cylinder is activated.
In various implementations, such as a port fuel injection engine, an array of Boolean flags may be defined, one for each cylinder. The flag corresponding to a cylinder is updated at the end of the cylinder's intake stroke. The flag is set to true if the cylinder had been fueled during its last intake stroke. The array can be summed to determine the number of cylinders that were fueled during their last intake stroke.
This count may be placed into a circular buffer, which is updated and read on a cylinder synchronous basis. The circular buffer introduces a delay, which may be measured in terms of cylinder events, from the end of the intake stroke until the time at which a spark change would be necessary to account for that cylinder's fueling change.
In various implementations, the delay may be from the intake stroke until an event that is used to schedule spark. The delay may be reduced to account for time used in switching domains from cylinder synchronous to time-based, which is the domain in which the torque control operates, and back to cylinder synchronous, which is the domain in which spark control operates.
The delayed cylinder count is referred to as the powered count. This is the count that can be used in the cylinder fraction term for spark control. To coordinate this cylinder fraction term with torque estimation, the cylinder fraction term may be saved from its time domain calculation into another variable at the time when the cylinder synchronous spark scheduling event occurs. This ensures that the time domain determination is able to be used by the time domain spark torque controller and then be consumed by the spark advance controller.
Those skilled in the art can now appreciate from the foregoing description that the broad teachings of the disclosure can be implemented in a variety of forms. Therefore, while this disclosure includes particular examples, the true scope of the disclosure should not be so limited since other modifications will become apparent to the skilled practitioner upon a study of the drawings, the specification, and the following claims. | An engine control system comprises a torque control module and a fueling control module. The torque control module selectively generates a deactivation signal for a first cylinder of a plurality of cylinders of an engine based on a torque request. The fueling control module halts fuel delivery to the first cylinder based on the deactivation signal. The torque control module increases a spark advance of the engine at a first time after the fueling control module halts fuel injection for the first cylinder. The first time corresponds to an initial time combustion fails to occur in the first cylinder because fuel delivery has been halted. | 49,282 |
TECHNICAL FIELD
This invention relates to light-sensitive compositions useful for defining patterns on substrates by photolithography, particularly to new photoresist compositions especially useful in microlithographic applications where it is desirable to form microscopically-sized patterns which exhibit exceptional resistance to plasma etching. The present invention also relates to precursor compositions used to form the photoresist compositions and methods for forming, the precursor compositions and the photoresist compositions.
BACKGROUND OF THE INVENTION
Semiconductor devices such as integrated circuits, solid state sensors and flat panel displays are produced by microlithographic processes in which a photoresist is used to form a desired feature pattern on a device substrate. Light is passed through a patterned mask onto the photoresist layer which has been coated onto the device substrate. A chemical change occurs in the light-struck areas of the photoresist, causing the affected regions to become either more soluble or less soluble in a chemical developer. Treating the exposed photoresist with the developer etches a positive or negative image, respectively, into the photoresist layer. The resulting pattern serves as a contact mask for selectively modifying those regions of the substrate which are not protected by the pattern. These modifications may include, for example, etching, ion implantation, and deposition of a dissimilar material.
Plasma etching processes are being used increasingly to transfer photoresist patterns into device substrates or underlying layers. It is important that the photoresist pattern does not erode excessively during the plasma etching process, otherwise, the precise pattern will not be transferred into the underlying layer. For example, if the photoresist is removed by the etching process before the underlying layer has been fully etched, then the feature size will begin to increase as the etching process proceeds since the photoresist is no longer protecting the area of the substrate which it once covered. Because of the precision required in etching this is disadvantageous.
Plasma etching processes for organic layers such as color filters used in solid state color sensors and flat panel displays require photoresist materials with exceptional resistance to oxygen plasma etching. Conventional photoresists cannot be used effectively since they are primarily mixtures of organic compounds and resins which are etched more rapidly than the color layers.
Silicon-containing photoresists and silylated photoresist products have been developed to provide greater etch selectivity when patterning organic layers by oxygen plasma etchinig. Such compositions have been described, for example, in U.S. Pat. No. 5,250,395 issued to Allen et al. and by F. Coopmans and B. Rola in Proceedings of the SPIE, Vol. 631, p. 34 (1986). During the etching process, the silicon components in the photoresist are rapidly converted to silicon dioxide which resists further etching. The in-situ formed silicon dioxide layer then becomes the mask for etching the underlying organic layer.
Although oxygen is normally the principal plasma etchant for organic layers, it may be admixed with various fluorinated gases such as NF 3 , C 2 F 6 , HCF 3 , and CF 4 to aid in the removal of inorganic residues arising from metallic species. The inorganic residues are often present, for example, in color filter layers. Since, silicon dioxide is readily etched by fluorine-containing plasma etchants, silicon-containing photoresists cannot be used effectively in plasma etching processes where fluorine-containing gases are present.
For color filter applications, it is also desirable that the plasma etch-resistant photoresist be left in place as a permanent part of the device structure after the etching process has been completed. To function suitably in this respect, the remaining photoresist material must be continuous, homogeneous, highly adherent, and optically clear so that it does not reduce the transmissivity of the color filter assembly. Silicon-containing photoresists often exhibit poor optical clarity after plasma etching or high temperature thermal treatments which are usually applied to color filter layers. This problem is especially prevalent with silylated phenolic photoresists since the phenolic components form highly colored species when heated to above approximately 125° C.
There are other microlithographic applications where it is also desirable to leave a processed photoresist layer in place as a permanent device structure. For example, thin barium titanate and lead zirconate titanate layers are needed as ferroelectrics in advanced memory devices. Presently, these complex metal oxides must be deposited by chemical vapor deposition and then patterned in separate plasma etching processes. Considerable time and expense could be saved if the materials could be applied in a photosensitive precursor form by spin coating and then directly patterned by a photolithographic process, after which the patterned layer would be calcined in air to form the desired metal oxide device features.
Accordingly, there is a need for a photoresist material with greater plasma etching resistance in processes utilizing oxygen and/or fluorinated gases as the etchant species. At the same time, there is a need for a photoresist which is convertible to a permanent metal oxide layer with chemical, thermal, electrical, and optical properties useful for device application and whose properties can be controlled by adjusting the composition of the photoresist. The photoresist should further possess high resolution patterning capabilities and be easily integrated into modern microlithographic processing schemes. We have now discovered that all of these requirements surprisingly can be met with a photoresist composition containing an addition polymerizable organotitanium polymer as the principal constituent.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a reaction showing the formation of an example organotitanium polymer;
FIG. 2 shows the crosslinking reaction that occurs when the polymer is applied onto the substrate and exposed to radiation which induces addition polymerization;
FIG. 3 shows a table which displays a variation of photoresist plasma etching resistance with baking conditions; and,
FIG. 4 is a continuation of the table of FIG. 3 .
SUMMARY OF THE INVENTION
It is a principle object of the present invention to provide a photoresist composition with improved resistance to plasma etching processes which utilize oxygen and/or fluorine-containing gases, as well as noble gases, as the etchant species, with oxygen and fluorine preferred. It is a further objective to provide a photoresist composition which exhibits the following desirable properties in addition to improved plasma etching resistance:
a) good coating quality and feature coverage when applied by spin coating onto electronic substrates;
b) high sensitivity to ultraviolet, electron beam, and x-ray exposing radiation;
c) facile image development in aqueous alkaline developers;
d) good pre-cure adhesion to polymer, metal, and semiconductor materials;
e) high resolution, i.e., feature sizes of approximately 1 micron or smaller should be readily obtainable; and,
f) curable to a continuous, homogeneous, and, if desired, optically clear (>90% transmissivity at 400-700 nm wavelengths for 0.25 micron film thickness) metal oxide layer having good adhesion to underlying device structures.
Lastly, it is an objective of this invention to provide a method for using the photoresist composition in a microlithographic process as a plasma etch-resistant masking layer or a permanent device structure.
The improved photoresist composition is comprised principally of: a) an addition polymerizable organotitanium polymer or copolymer, b) a photopolymerization initiator or initiator system, and c) a solvent vehicle.
The photoresist composition is preferably coated onto a substrate by any of a variety of means, with spin coating preferred, and then dried to obtain a uniform, defect-free layer, which is then exposed to ultraviolet radiation through a patterned mask to generate a latent image. The exposed photoresist is etched in an alkaline aqueous solution or an aqueous chelate solution. having a pH greater than 10, to leave a negative-tone image of the mask in the layer. The patterned structure is baked in air and/or exposed to an oxygen-containing plasma to partially or fully convert the photoresist material into a titanium-containing metal oxide layer with high plasma etching resistance. The resulting metal oxide layer may be used as a mask for modifying underlying, layers by plasma etching, implantation, deposition, or other processes. Depending on its final physical and chemical properties, it may be left in place as a permanent device structure after the processing sequence has been completed.
DETAILED DESCRIPTION OF THE INVENTION
The improved photoresist composition of the present invention is preferably comprised of:
a) an addition polymerizable organotitanium polymer or copolymer prepared by reacting a poly(alkyltitanate) or poly(alkyltitanate-co-alkylmetallate) with an alcohol, carboxylic acid, beta-diketone, beta-ketoester, or alpha-hydroxy carboxylic acid, acid salt, or ester having at least one ethylenically unsaturated double bond capable of addition polymerization, wherein the copolymerized alkylmetallate moiety is selected from the group consisting of —(RO)Al—O—, —(RO) 2 Zr—O—, —(R′) 2 Si—O—, —(R′)(RO)Si—O—, and —(RO) 2 Si—O—, and where R and R′ are monovalent organic radicals;
b) a free radical-generating, photopolymerization initiator or initiator system;
c) a solvent vehicle suitable for obtaining high quality thin films on device substrates by spin casting.
The composition may additionally contain one or both of the following constituents:
d) an addition polymerizable co-monomer having at least one ethylenically unsaturated double bond, wherein the co-monomer may contain a covalently bonded metal; and,
e) a soluble metallic compound which is stable in the presence of the other photoresist ingredients.
It will be apparent to those skilled in the art that the organotitanium polymer or copolymer used in the title invention, and which upon heat treatment forms a metal oxide composition, is inherently capable of addition polymerization by virtue of the ethylenically unsaturated double bonds present within its structure. Therefore, it is expected that the organotitanium polymer or copolymer could be used alone in solution or in combination with some, but not necessarily all, of the above-mentioned constituents to prepare coatings which can be patterned by selective exposure to ionizing radiation, assuming such radiation is capable of inducing addition polymerization in the coating. For example, the improved photoresist composition may be exposed to an electron beam or x-ray source to form a negative-tone image in a manner analogous to exposure to ultraviolet light. In such instances, the inclusion of a free radical-generating photopolymerization initiator or initiator system may not be necessary for patterning since the high energy radiation can induce crosslinking in the exposed areas of the coating.
Components Of Composition
a. Addition Polymerizable Organotitanium Polymer
Organotitanium polymers suitable for use in the new photoresist composition include the reaction products of poly(alkyltitanates) and poly(alkyltitanates-co-alkylmetallates) with addition polymerizable alcohols, carboxylic acids, beta-diketones, beta-ketoesters, and alpha-hydroxy carboxylic acids, acid salts, and esters. For example, poly(n-butyl titanate) can be reacted with 2-hydroxyethyl acrylate to form the following polymeric titanate ester (1) which is capable of addition polymerization:
—[Ti(OR a ) x (OBu) y —O] n — (1)
where R a =—CH 2 —CH 2 —O—CO—CA=CH 2 , Bu=—CH 2 —CH 2 CH 2 —CH 3 , x+y=2, x=0.1-2.0, A=—H or —CH 3 , and n>2.
Poly(alkyltitanates) can also be reacted with acrylic acid or other addition polymerizable carboxylic acids to produce polymeric titanium acylates useful in the present invention. The reaction of poly(in-butyltitaniate) with acrylic acid, for example, results in the following polymeric product (2) which is capable of addition polymerization:
—[Ti(OR b ) x (OBu) y —O] n — (2)
where R b =—O—CO—CA=CH 2 , Bu=—CH 2 —CH 2 —CH 2 —CH 3 , x+y=2, x=0.1-2.0, A=—H or —CH 3 , and n>2.
Similarly, poly(alkyltitanates) can be reacted with beta-diketones, beta-ketoesters, and alpha-hydroxy carboxylic acids, acid salts, and esters containing addition polymerizable groups to produce polymeric titanium chelates useful in the present invention. For example, the reaction of poly(n-butyltitanate) with 2-acetoacetoxyethyl methacrylate, a beta-ketoester, results in the following, polymeric product (3) which is capable of addition polymerization:
where R c =—CH 2 —CH 2 —O—CO—C(CH 3 )=CH 2 Bu=—CH 2 —CH 2 —CH 2 —CH 3 , x+y=2, x=0.1-2.0, and n>2.
The reaction of poly(n-butyltitanate) with an addition polymerizable alpha-hydroxy carboxylic acid salt also yields a polymeric titanium chelate (4) useful in the present invention, for example:
where B + =(H 3 C) 2 NH + —R—CO—CA=CH 2 , R=—CH 2 —CH 2 —CH 2 —NH— or —CH 2 —CH 2 —O—, Bu=—CH 2 —CH 2 —CH 2 —CH 3 , x+y=2, x=0.1-2.0, A=—H or —CH 3 , and n>2.
An example of how the organotitanium polymer is formed is shown in FIG. 1 .
It will be apparent to those skilled in the art that useful addition polymerizable organotitanium polymers can also be prepared by reacting poly(alkyltitanates) with other known titanium chelants which have been functionalized to enable free radical-initiated polymerization. It will be further apparent that functionally equivalent, addition polymerizable organotitanium polymers can be prepared in principle by reacting, for examples titanate orthoesters having at least one ethylenically unsaturated double bond with a limited amount of water to form a soluble polymeric condensation product. Lastly, it is inferred that addition polymerizable organometallic polymers useful for the present invention can be prepared similarly from copolymers of alkyltitanates with alkylsilicates (siloxanes) and other alkylmetallates, notably those of aluminum, zirconium, cerium, niobium, and tantalum.
b. Photopolymerization Initiators or Initiator Systems
All known free radical initiators or initiator systems which operate effectively at 200-500 nm exposing wavelengths can be substantially employed as the photopolymerization initiator or initiator system for the present invention. The free radical initiator decomposes upon exposure to ultraviolet light, forming a species which has an unpaired electron or is capable of extracting a proton from another molecule so that the latter carries an unpaired electron. The free radical thus formed adds readily to an unsaturated double bond, especially acrylate-type double bonds, to generate a new free radical which then reacts with another double bond-containing molecule, and so on, creating a polymer chain in the process. The polymer-forming process is called addition polymerization. Examples of suitable initiators and initiator systems include:
1) trihalomethyl-substituted triazines such as p-methoxy phenyl-2,4-bis(trichloromethyl)-s-triazine;
2) trihalomethyl-substituted oxadiazoles such as 2-(p-butoxy styryl) chloromethyl-1,3,4-oxadiazole;
3) imidazole derivatives such as 2-(2′-chlorophenyl)-4,5-diphenylimidazole dimer (with a proton donor such as mercaptobenzimidazole);
4) hexaaryl biimidazoles such as 2,2′-bis(o-chlorophenyl) 4,4′,5,5′-tetraphenylbiimidazole;
5) benzoin alkyl ethers such as benzoin isopropyl ether;
6) anthraquinone derivatives such as 2-ethylanthraquinone;
7) benzanthrones;
8) benzophenones such as Michler's ketone;
9) acetophenones such as 2,2-diethoxy-2-phenylacetophenone;
10) thioxanthones such as 2-isopropylthioxanthone;
11) benzoic acid ester derivatives such as octyl p-dimethyl aminobenzoate;
12) acridines such as 9-phenylacridine;
13) phenazines such as 9,10-dimethylbenzphenazine; and,
14) titanium derivatives such as bis(cyclopentadienyl)-bis(2,6-difluoro-3-(pyl-1-yl) titanium.
These photopolymerization initiators may be used alone or in admixture. An example would be combining 2-isopropylthioxanthone with octyl p-dimethylaminobenzoate.
c. Solvent Vehicle and Additives
Suitable solvents for the new photoresist composition include alcohols, esters, glymes, ethers, glycol ether, ketones and their admixtures which boil in the range 70°-180° C. Especially preferred solvents include 1-methoxy-2-propanol (PGME), 2-butoxyethanol, cyclohexanone, 2-heptanone, ethyl 3-ethoxypropionate, propylene glycol methyl ether acetate, and other common photoresist solvents. Solvent systems containing an alcohol, such as PGME, are preferred for obtaining improved hydrolytic stability of the photoresist composition. Solvents such as ethyl acetoacetate and ethyl lactate may be used in the photoresist composition provided they do not cause side reactions with the photosensitive organotitanium polymer.
The photoresist composition may be augmented with small amounts (up to 20 wt. % of total solvents) of high boiling solvents such as N-methylpyrrolidone, gamma-butyrolactone, and tetrahydrofurfuryl alcohol to improve the solubility of the coating components, provided the solvents do not cause coating quality problems. Surface tension modifiers such as 3M Company's FLUORADO® FC-171 or FC-430 fluorinated surfactants may be added at low levels (approximately 1000 parts per million) to optimize coating quality without affecting the lithographic properties of the photoresist.
d. Co-monomers
Co-monomers having at least one ethylenically unsaturated double bond capable of addition polymerization may be added to the photoresist composition to improve the photospeed, resolution, or physical and chemical properties of the photoresist layer. Preferred comonomers carry multiple acrylate groups which participate in the addition polymerization process described above in the initiation and initiator systems. From the standpoint of the polymerization, co-monomers are indistinguishable from the (meth)acrylate groups on the organotitanium polymer. The comonomer can serve many purposes for example: 1) it can modify film properties from what would be obtained with the organotitanium polymer only, e.g., it can make the product softer or harder, 2) it can increased the photospeed by providing a higher concentration of polymerizable groups in the coating, or 3) it can change the development properties of the coating by making it more or less soluble in basic developer. Examples of suitable comonomers include mono- and polyfunctional (meth)acrylate esters such as 2-hydroxyethyl (meth)acrylate; ethylene glycol dimethacrylate, pentaerythritol triacrylate, and tetraacrylate; dipentaerythritol pentaacrylate and hexaacrylate; polyester (meth)acrylates obtained bv reacting (meth)acrylic acid with polyester prepolymers; urethane (meth)acrylates; epoxy (meth)acrylates prepared by reacting (meth)acrylic acid with epoxy resins such as bisphenol-A type epoxy resins, bisphenol-F type epoxy resins, and novolak-type epoxy resins; and, tris(2-acryloyloxyethyl) isocyanurate.
Suitable co-monomers also include acrylic-functional metal complexes prepared, for example, by tranesterifying titanium or zirconium alkoxides with 2-hydroxyethyl acrylate or a chelating organic moiety. The use of such metal-containing, co-monomers is advantageous for maintaining high metal content in the photoresist composition.
e. Non-Photopolymerizable Metallic Compounds
Non-photopolymerizable metallic compounds may be added to the photoresist composition to increase metal content or obtain complex metal oxide compositions from the processed photoresist layer. Suitable compounds include soluble metal carboxylates, metal alkoxides, metal hydroxides, metal chelates, and simple metal salts such as metal chlorides or nitrates. The amount and type of metal compounds which can be added are governed by 1) their solubility in the liquid photoresist as well as in the dried photoresist layer (an added metal compound should not crystallize in the dried film); 2) their overall effect on the lithographic properties of the photoresist; and, 3) their reactivity with the other photoresist components. It is especially important that added metal compounds do not cause precipitation of the organotitanium polymer or reduce its polymerizability through unwanted side reactions.
f. Other Compounds
Non-reactive organic compounds may be added to the photoresist composition to modify the properties of the photoresist layer. For example, solvent-soluble dyes can be added to the composition to prepare a patternable, permanently colored layer for light-filtering applications. Pigments can also be dispersed in the photoresist to obtain a directly patternable colored product. The ability to add these materials depends on their compatibility with the other photoresist components and their impact on the lithographic properties of the coating.
Method of Preparation
a. Preparation of Photopolymerizable Organotitanium Polymer
The addition polymerizable organotitanium polymer is preferably prepared by reacting in solution a poly(alkyltitanate) or poly(alkyltitanate-co-alkylmetallate) with a stoichiometric excess of an alcohol, carboxylic acid, beta-diketone, beta-ketoester, or alpha-hydroxy carboxylic acid, acid salt, or ester having at least one ethylenically unsaturated double bond capable of addition polymerization. The ester substituents on the starting polymer are substituted by the polymerizable reactants to form the final photosensitive product. The solution may be heated to about 70° C. for several hours to increase the rate and yield of the substitution reaction. By-product alcohol may be removed continuously from the reactor by vacuum distillation to drive the reaction to completion.
b. Formulation of Photoresist
The addition polymerizable organotitanium polymer, photopolymerization initiator(s), and, if present, co-monomers, and non-photopolymerizable metallic and organic compounds are combined by stirring in a portion of the solvent system and then diluted with additional portions of the solvent system until the desired total solids level is obtained. A total solids level of 30 wt. % is typically required in the solution to achieve a film thickness of 500-2500 Å when it is spin coated at 1000-5000 rpm for 30-90 seconds and then dried at approximately 100° C. Prior to the final dilution, the photoresist solution or its components may be treated, for example, by ion exchange processes to remove metal ion contamination. Preferred compositional ranges (expressed in wt. % based on total solids content) for each of the photoresist components are summarized in the table below:
Component
Useful Range %
Preferred Range %
addition polmerizable
15-90
40-80
organotitanium polymer or
copolymer
photoinitiator or photoinitiator
1-20
10-15
system
co-monomers
0-80
0-50
non-photopolymerizable
0-60
0-40
metallic and organic compounds
or pigments
Method of Use
The improved photoresist composition can be used effectively on most ceramic, metal, polymer, and semiconductor substrates including, for example, glass, sapphire, aluminum nitride, crystalline and polycrystalline silicon, silicon dioxide, silicon (oxy)nitride, aluminum, aluminum/silicon alloys, copper, platinum, tungsten, and organic layers such as color filters and polyimide coatings. The photoresist is coated onto the substrate by any of a variety of means including spin coating, roller coating, blade coating, meniscus or slot coating, and spray coating. Spin coatings, however, is most preferred with the photoresist applied by spin coating at 500-5000 rpm for 30-90 seconds. Spinning speeds of 1000-4000 rpm are especially preferred for obtaining uniform, defect-free coatings on 6″ and 8″ semiconductor substrates. The spin-coated film is dried typically at 80-120° C. for 30-120 seconds on a hot plate or equivalent baking unit prior to exposure. The photoresist is preferably applied at a film thickness of 0.05-1.00 micron (as-spun) and, more typically, to a film thickness of 0.10-0.50 micron by adjusting both the total solids level of the photoresist and the spinning speed and time to give the desired layer thickness. While the before mentioned thicknesses are preferred, the photoresists can be applied to a thickness of several microns if desired, assuming a sufficient level of polymer solids can be supported in the photoresist solution. Film thickness can be increased by increasing solids content, reducing the spinning speed, and formulating the resist with faster-drying solvents.
A latent image is formed in the photoresist layer by exposing it to ultraviolet radiation through a mask. An exposure dose of 10-1000 mJ/cm 2 is typically applied to the photoresist to define the latent image. Alternatively, regions of the photoresist layer may be exposed to electron beam or x-ray radiation to form a latent negative-tone image. An example of the radiation-induced crosslinking reation that occurs in the exposed areas is shown in FIG. 2 . The exposed photoresist layer is developed in aqueous alkali or an aqueous chelant solution to form the final pattern.
For use as a plasma etching mask, the patterned photoresist is converted to an etch-resistant metal oxide layer by one of two techniques. In the first, it is baked in air at 150°-300° C. for 15-60 minutes to decompose the organic components and leave a predominantly inorganic layer which is etch-resistant. The processed photoresist layer can then be used as a mask for plasma etching an underlying layer with oxygen or a fluorinated gas species.
In the second method, the patterned photoresist is applied and patterned over an organic layer such as a color filter. The two-layer structure is placed directly in a plasma etching environment where oxygen is the principal etching species. (Prior thermal decomposition is not required). Tlhe photoresist layer is partially converted to a metal oxide film during the initial portion of the process and then serves as an etching mask for the organic layer.
It is becoming popular to planarize surface topography during( the construction of integrated circuits in order to reduce photoresist thickness variations across the substrate and thereby enhance feature size control. In such instances, a relatively thick organic layer may be applied over the device features to form a planar surface. A thin photoresist is then applied onto the structure and used to pattern the organic planarizing layer by oxygen plasma etching. The remaining photoresist and the planarizing layer form a composite mask, or bilayer photoresist system, for etching or otherwise modifying the substrate. The new photoresist can be used very effectively in such processes because of its combined resistance to oxygen- and fluorinie-containing plasma etching processes. The use of the new photoresist in a bilayer configuration essentially follows the process described above for patterning an organic color filter. After the planarizing layer has been cleared by oxygen plasma etching, a fluorinated etchant may be introduced to etch the substrate. Unlike silicon-containing, bilayer photoresists which erode under these conditions, the new photoresist shows less degradation, which helps to maintain better edge acuity on the photoresist features throughout the etching process. This in turn reduces negative etch biasing caused by lateral erosion of the bilayer photoresist features. Once these modifications have been completed, the bilayer photoresist structure is lifted off by dissolving, the organic planarizing layer from beneath the metal oxide mask. The device substrate is then ready for another processing cycle.
When used to deposit permanent metal oxide device features, the photoresist is applied onto the device substrate, patterned, and then heated in air to form an metal oxide layer. The metal oxide may be calcined at high temperatures (>300° C.) to obtain a densified polycrystalline structure which has physical properties more suitable for device applications.
EXAMPLES
Example 1
A photorcsist composition corresponding to the present invention was prepared and used to pattern a color filter layer by a plasma etchings process.
a. Preparation of Photopolymerizable Organotitanium Polymer
Fifteen (15) parts by weight of poly(n-butyltitanate) obtained from Geleste Corporation were combined with 20 parts by weight of 2-hydroxyethyl acrylate (2-HEA) in a closed container and heated for approximately one hour to cause substitution of the titanate ester groups by 2-HEA. The resulting solution was used to prepare the photoresist composition described below.
b. Photoresist Formulation
A photoresist composition was prepared by combining 25.9 g of the above polymer solution, with 1.0 g of 2-isopropyl-9H-thioxanthen-9-one, and 3.0 g octyl p-dimethylaminobenzoate in 70.1 g propylene glycol methyl ether to form a solution containing 29.9 wt. % total solids.
c. Patterning Trials on Silicon
The photoresist composition was spin coated onto silicon wafers at 3000 rpm for 60 sec and then dried at 100° C. for 60 see on a hot plate to obtain 1600 Å-thick film specimens. The coated specimens were exposed to a broadband ultraviolet light source through a contact mask to form a latent negative image in the photoresist film. An exposure dose of 100 mJ/cm 2 was applied. The exposed specimens were developed for 5-10 seconds in 0.26 N tetramethylammonium hydroxide solution to form sharply defined, isolated, and dense features as small as 1 micron in width. The smallest features were retained at all points across the substrate, indicating that the photoresist had excellent adhesion to the silicon substrate.
Patterned specimens were placed individually in a March plasma etclhilng system and exposed to an oxygen-rich plasma for periods ranging from 1-60 minutes. Comparison of film thickness before and after exposure to the plasma showed that the starting film thickness of 1600 Å quickly decreased to 1100 Å, after which no further change was observed regardless of the etching time. The results clearly indicated that the organic components of the photoresist were rapidly removed by the oxygen plasma, leaving a titania layer which resisted further etching.
d. Pattern Transfer into an Organic Color Layer
The patterning process with the photoresist composition was repeated with the photoresist film now applied onto a substrate which had been previously coated with a 1.5 micron-thick polyimide color filter containing solvent-soluble organic dyes. (The color filter was baked at 230° C. for 1 hour prior to applying the photoresist.) Microscopic inspection of the photoresist layer immediately after patterning showed that two-micron and larger-sized features were retained across the substrate during the development process. The specimen was placed in a March plasma etching system and exposed to a plasma comprised of 90% O 2 and 10% CF 4 . After a 10-minute etch, the color filter was cleanly removed from those areas not protected by the photoresist. The photoresist remained uniformly intact on the color features at all points on the specimen.
Example 2
A photoresist composition corresponding to the present invention was prepared from an organotitanium polymer formed by the reaction of poly(n-butyltitanate) and an addition photopolymerizable beta-ketoester. The polymer showed improved solution stability in comparison to the organotitanium polymer used in Example 1.
a. Preparation of Photopolymerizable Organotitanium Polymer
In a 250 ml, oven-dried, round bottom flask fitted with a drying tube 29.67 g of poly(n-butyltitanate), containing a calculated 0.282 moles of reactive n-butyl ester groups, were combined with 66.32 g of 2-methacryloxyethyl acetoacetate (MEAA). The solution was stirred at room temperature for about 20 minutes and then immersed in an oil bath for 24 hours at 70-80° C. to cause substitution of the titanate ester groups by MEAA. Thie resulting polymer solution was used to prepare the photoresist composition described in section (b) below.
A second preparation of the same polymer was placed in a 50° C. oven for two weeks to determine its stability against gellation. The gold-yellow polymer solution exhibited a kinematic viscosity of 19.62 Centistokes at the beginning of the period. After two weeks at 50° C. the color of the solution was unchanged and its viscosity had decreased to 18.18 Centistokes (−7.3%), indicating the solution possessed excellent stability. When a solution of the photopolymerizable organotitanium polymer used in Example 1 was aged similarly, it gelled within 24 hours.
b. Photoresist Formulation
A photoresist composition was prepared by combining 26.0 g of the above polymer solution, 1.0 g of 2-isopropyl-9H-thioxanthen-9-one, and 3.0 g octyl p-dimethylaminiobenzoate in 74.1 g propylene glycol methyl ether. The solution was stirred for 1 hr at room temperature and then passed through a 0.2 μm endpoint filter to remove particulates prior to spin coating.
c. Patterning Trails on Silicon
The photoresist composition was spin coated onto silicon wafers at 3000 rpm for 60 sec and then dried at 100° C. for 60 sec on a hot plate to obtain 1500 Å-thick film specimens. The coated specimenis were exposed to a broadband ultraviolet light source through a contact mask to form a latent negative image in the photoresist film. An exposure dose of approximately 300 mJ/cm 2 was applied. The exposed specimens were developed for about 5 minutes in dilute potassium carbonate solution to form sharply defined, isolated, and dense features as small as 1 micron in width. The smallest features were retained at all points across the substrate, indicating that the photoresist had excellent adhesion to the silicon substrate.
d. Testing of Plasma Etching Resistance
The ability of the photoresists to withstand plasma etching in 90% O 2 /10% CF 4 was evaluated after applying various heat treatments (bakes) to the photoresists. It was expected that plasma etching resistance would improve as baking temperature and/or time increased since more of the easily etchable carbonaceous material would be removed from the photoresist layer prior to plasma etching by the heat treatment. The resistance of the photoresist to plasma etching in pure oxygen was determined at the same time. The results of the evaluations are summarized in Table 1.
The data in Table 1 indicated that the film thickness of the photoresist layer was highly dependent on the bake process applied to the layer prior to plasma etching. As bake temperature and time increased, more of the carbonaceous components were outgassed from the film, causing pre-etch film thickness to progressively decrease. Heat treatment of the photoresist layer improved resistance to O 2 /CF 4 etching as evidenced by the fact that post-etch photoresist thickness increased as bake temperature and time increased. The photoresist layer was highly resistant to plasma etching in pure oxygen regardless of the manner of heat treatment. | A composition is derived from an addition polymerizable organotitanium polymer which upon exposure to an oxygen plasma or baking in air, is converted to titanium dioxide (titania) or is converted to a mixed, titanium-containing metal oxide. The metal oxide formed in situ imparts etch-resistant action to a patterned photoresist layer. The composition may also be directly deposited and patterned into permanent metal oxide device features by a photolithographic process. | 37,216 |
BACKGROUND OF THE INVENTION
The present invention is directed to processes for ink jet printing. More specifically, the present invention is directed to ink jet printing processes employing an improved ink composition. One embodiment of the present invention is directed to a thermal ink jet printing process which comprises (a) incorporating into a thermal ink jet printer an ink composition comprising water, a dye, and pigment particles having an average particle diameter of from about 0.001 micron to about 10 microns, said pigment particles being present in the ink in an amount of less than 0.1 percent by weight; and (b) causing droplets of the ink to be ejected in an imagewise pattern onto a recording medium by selectively heating the ink in the printer in an imagewise pattern, thereby generating images on the recording medium.
Ink jet printing systems generally are of two types: continuous stream and drop-on-demand. In continuous stream ink jet systems, ink is emitted in a continuous stream under pressure through at least one orifice or nozzle. Multiple orifices or nozzles also can be used to increase imaging speed and throughput. The stream is ejected out of orifices and perturbed, causing it to break up into droplets at a fixed distance from the orifice. At the break-up point, the electrically charged ink droplets are passed through an applied electrode which is controlled and switched on and off in accordance with digital data signals. Charged ink droplets are passed through a controllable electric field which adjusts the trajectory of each droplet in order to direct it to either a gutter for ink deletion and recirculation or a specific location on a recording medium to create images. The image creation is controlled by electronic signals.
In drop-on-demand systems, a droplet is ejected from an orifice directly to a position on a recording medium by pressure created by, for example, a piezoelectric device, an acoustic device, or a thermal process controlled in accordance with digital data signals. An ink droplet is not generated and ejected through the nozzles of an imaging device unless it is needed to be placed on the recording medium.
Since drop-on-demand systems require no ink recovery, charging, or deflection operations, the system is simpler than the continuous stream type. There are three types of drop-on-demand ink jet systems. One type of drop-on-demand system has an ink filled channel or passageway having a nozzle on one end and a regulated piezoelectric transducer near the other end to produce pressure pulses. The relatively large size of the transducer prevents close spacing of the nozzles necessary for high resolution printing, and physical limitations of the transducer result in low ink drop velocity. Low drop velocity may seriously diminish tolerances for drop velocity variation and directionality, thus impacting the system's ability to produce high quality copies, and also decreases printing speed. Drop-on-demand systems which use piezoelectric devices to eject the ink droplets also suffer the disadvantage of a low resolution. A second type of drop-on-demand ink jet device is known as acoustic ink printing which can be operated at high frequency and high resolution. The printing utilizes a focused acoustic beam formed with a spherical lens illuminated by a plane wave of sound created by a piezoelectric transducer. The focused acoustic beam reflected from a surface exerts a pressure on the surface of the liquid, resulting in ejection of small droplets of ink onto an imaging substrate. Aqueous inks can be used in this system.
The third type of drop-on-demand system is known as thermal ink jet, or bubble jet, and produces high velocity droplets and allows very close spacing of nozzles. The major components of this type of drop-on-demand system are an ink filled channel having a nozzle on one end and a heat generating resistor near the nozzle. Printing signals representing digital information generate an electric current pulse in a resistive layer (resistor) within each ink passageway near the orifice or nozzle, causing the ink in the immediate vicinity of the resistor to be heated up periodically. Momentary heating of the ink leads to its evaporation almost instantaneously with the creation of a bubble. The ink at the orifice is forced out of the orifice as a propelled droplet at high speed as the bubble expands. When the hydrodynamic motion of the ink stops after discontinuous heating followed by cooling, the subsequent ink emitting process is ready to start all over again. With the introduction of a droplet ejection system based upon thermally generated bubbles, commonly referred to as the "bubble jet" system, the drop-on-demand ink jet printers provide simpler, lower cost devices than their continuous stream counterparts, and yet have substantially the same high speed printing capability.
The operating sequence of the bubble jet system begins with a current pulse through the resistive layer in the ink filled channel, the resistive layer being in close proximity to the orifice or nozzle for that channel. Heat is transferred from the resistor to the ink. The ink becomes superheated far above its normal boiling point, and for water based ink, finally reaches the critical temperature for bubble nucleation and formation of around 280° C. and above. Once nucleated and expanded, the bubble or water vapor thermally isolates the ink from the heater and no further heat can be applied to the ink. This bubble expands rapidly due to pressure increase upon heating until all the heat stored in the ink in excess of the normal boiling point diffuses away or is used to convert liquid to vapor, which removes heat due to heat of vaporization. The expansion of the bubble forces a droplet of ink out of the nozzle located either directly above or on the side of a heater, and once the excess heat is removed with diminishing pressure, the bubble collapses on the resistor. At this point, the resistor is no longer being heated because the current pulse has been terminated and, concurrently with the bubble collapse, the droplet is propelled at a high speed in a direction towards a recording medium. Subsequently, the ink channel refills by capillary action and is ready for the next repeating thermal ink jet process. This entire bubble formation and collapse sequence occurs in about 30 microseconds. The heater can be reheated to eject ink out of the channel after 100 to 2,000 microseconds minimum dwell time and to enable the channel to be refilled with ink without causing any dynamic refilling problem. Thermal ink jet processes are well known and are described in, for example, U.S. Pat. Nos. 4,601,777, 4,251,824, 4,410,899, 4,412,224, and 4,532,530, the disclosures of each of which are totally incorporated herein by reference.
Ink jet inks containing pigment particles as colorants are known. For example, in Dunn, "Waterproof Carbon Black Ink for Ink Jet Printing," Xerox Disclosure Journal, Vol. 4, No. 1 (1979), a waterproof colloidal carbon black ink for ink jet printing is disclosed. The ink is prepared by incorporating a water-resistant acrylic polymer binder into an ink jet ink, such that the ink composition comprises about 9 percent by weight of carbon black, about 2 percent by weight of an anionic polymer-type dispersing agent, about 5 percent by weight of polyethylene glycol, about 8 percent by weight of Carboset 514H, and about 76 percent by weight of ammoniated distilled water. Sufficient ammonium hydroxide is added to the ink to adjust the pH to 8.5. According to the article, this ink composition is particularly suited to ink jets run in a continuous mode.
U.S. Pat. No. 4,597,794 (Ohta et al.), the disclosure of which is totally incorporated herein by reference, discloses an ink jet recording process which comprises forming droplets of an ink and recording on an image receiving material by using the droplets, wherein the ink is prepared by dispersing fine particles of a pigment into an aqueous dispersion medium containing a polymer having both a hydrophilic and a hydrophobic construction portion. The hydrophilic portion constitutes a polymer of monomers having mainly additively polymerizable vinyl groups, into which hydrophilic construction portions such as carboxylic acid groups, sulfonic acid groups, sulfate groups, and the like are introduced. Pigment particle size may be from several microns to several hundred microns. The ink compositions disclosed may also include additives such as surfactants, salts, resins, and dyes.
U.S. Pat. No. 3,705,043 (Zabiak) discloses an ink suitable for jet printing which comprises a high infrared absorbing coloring component and a humectant in the form of an aliphatic polyol, alkyl ether derivatives of aliphatic polyols, and mixtures thereof in aqueous media. The infrared absorber component may be a high infrared absorptive water soluble dye, a solution of water dispersed carbon blacks, or mixtures thereof.
U.S. Pat. No. 3,687,887 (Zabiak) discloses an ink jet ink having application onto a film base which comprises an aqueous system containing 1 to 5 percent by weight of a dissolved styrene-maleic anhydride resin, 3 to 20 percent by weight of glycol ethers, and up to 4 percent by weight of carbon black in suspension or 1 to 4 percent of orthochromatic dyes in solution, or both, plus additives such as tinting dyes. Example 1 of this patent discloses a general ink formulation containing carbon black and a glycol ether, which may be an ethylene glycol type ether.
Japanese Patent 59-93765 discloses a recording liquid for ink jet printers. The ink disclosed therein is designed for dissolution stability at temperatures above 250° C. to prevent damage to the ink jet head, and comprises a dye, a solvent such as water, an organic solvent, an optional surface tension controller, a viscosity controller, and other additives. An amount of C.I. Food Black 2 is used as the colorant, and is present in the liquid in an amount of 0.5 to 15 percent by weight.
U.S. Pat. No. 4,273,847 (Lennon et al.) discloses a printing ink comprising particles of small size, each having a body portion consisting of a fusible resin with a colorant dispersed therein and an electrically conductive material, which may be carbon particles, situated substantially entirely on the surface of the body portion and comprising 5 to 10 percent of the weight of the ink. The disclosed ink is suitable for use in pulsed electrical printing.
U.S. Pat. No. 4,530,961 (Nguyen et al.) discloses an aqueous dispersion of carbon black grafted with hydrophilic monomers of alkali or ammonium carboxylate bearing polyacrylates, which suspension may be used for manufacturing ink jet inks. The dispersion has a viscosity of about 2 to about 30 centipoise for a carbon black content of about 1 to 15 percent by weight. This composition may also contain surfactants, wetting agents, dyes, mold inhibitors, oxygen absorbers, buffering agents, pH controlling agents, and viscosity controlling agents. Carbon black particles contained in the composition are of a size that permits them to pass easily through 1 to 50 micron mesh filters.
U.S. Pat. No. 4,877,451 (Winnik et al.), the disclosure of which is totally incorporated herein by reference, discloses ink jet ink compositions comprising water, a solvent, and a plurality of colored particles comprising hydrophilic porous silica particles to the surfaces of which dyes are covalently bonded through silane coupling agents.
U.S. Pat. No. 5,139,574 (Winnik et al.), the disclosure of which is totally incorporated herein by reference, discloses an ink composition which comprises an aqueous liquid vehicle, a water-soluble dye, and particles of a block copolymer of the formula ABA, wherein A represents a hydrophilic segment and B represents a hydrophobic segment, said ABA particles having an average diameter of about 300 Angstroms or less. The ink is particularly suitable for use in ink jet printing systems, especially thermal ink jet printing systems.
U.S. Pat. No. 5,145,518 (Winnik et al.), the disclosure of which is totally incorporated herein by reference, discloses an ink composition which comprises an aqueous liquid vehicle and particles of an average diameter of 100 nanometers or less which comprise micelles of block copolymers of the formula ABA, wherein A represents a hydrophilic segment and B represents a hydrophobic segment, and wherein dye molecules are covalently attached to the micelles, said dye molecules being detectable when exposed to radiation outside the visible wavelength range. Optionally, silica is precipitated within the micelles. In a specific embodiment, the dye molecules are substantially colorless. In another specific embodiment, the ink also contains a colorant detectable in the visible wavelength range.
U.S. Pat. No. 5,281,261 (Lin), the disclosure of which is totally incorporated herein by reference, discloses an ink composition comprising an aqueous liquid vehicle and pigment particles having attached to the surfaces thereof a polymerized vinyl aromatic salt.
U.S. Pat. No. 5,221,332 (Kohlmeier), the disclosure of which is totally incorporated herein by reference, discloses an ink composition which comprises an aqueous liquid vehicle, a colorant, and silica particles in an amount of from about 0.5 to about 5 percent by weight.
U.S. Pat. No. 4,836,852 (Knirsch et al.), the disclosure of which is totally incorporated herein by reference, discloses an ink formed by a solution of a direct dye in a mixture of water and glycol wetting agents, to which a pigment which is finely ground to particles of dimension of not more than 1000 Angstroms is added in dispersion, in a concentration of between 0.1 and 2 percent. The pigment particles serve to anchor the gaseous nuclei of gases which are dissolved in the ink for the purpose of stabilizing the boiling point of the ink. The ink is particularly suited to an ink jet printer of the type in which expulsion of the droplets is produced by causing instantaneous vaporization of a portion of ink in a nozzle.
U.S. Pat. No. 5,106,417 (Hauser et al.), the disclosure of which is totally incorporated herein by reference, discloses aqueous, low viscosity, stable printing ink compositions suitable for drop-on-demand ink jet printing containing specific selected amounts of a solid pigment preparation, a water-soluble organic solvent, a humectant and water so that the compositions resist clogging ink jet nozzles and give prints of excellent image resolution which are resistant to water and migration.
U.S. Pat. No. 5,085,698 (Ma et al.), the disclosure of which is totally incorporated herein by reference, discloses a pigmented ink for ink jet printers which comprises an aqueous carrier medium, and pigment particles dispersed in an AB or BAB block copolymer having a hydrophilic segment and a segment that links to the pigment. The A block and the 13 block(s) have molecular weights of at least 300. These inks give images having good print quality, water and smear resistance, lightfastness, and storage stability.
U.S. Pat. No. 5,026,427 (Mitchell et al.), the disclosure of which is totally incorporated herein by reference, discloses a process for the preparation of pigmented ink jet inks comprising: (a) mixing at least one pigment and at least one pigment dispersant in a dispersant medium to form a pigmented ink mixture wherein pigment is present in an amount up to 60% by weight based on the total weight of the mixture; (b) deflocculating the pigmented ink mixture by passing the pigmented ink mixture through at least a plurality of nozzles within a liquid jet interaction chamber at a liquid pressure of at least 1,000 psi to produce a substantially uniform dispersion of pigment particles in the dispersant medium.
While known compositions and processes are suitable for their intended purposes, a need remains for ink compositions particularly suitable for use in thermal ink jet printing processes. In addition, there is a need for ink compositions which, when employed in thermal ink jet printing processes, exhibit increased drop size, drop mass, and drop volume. Further, there is a need for ink compositions which, when employed in thermal ink jet printing processes, exhibit uniform drop speed over varying frequencies. Additionally, a need remains for ink compositions which, when employed in thermal ink jet printing processes, exhibit high ink drop velocity or short transit time. There is also a need for ink compositions which, when employed in thermal ink jet printing processes, exhibit a high jetting momentum, which is beneficial for printhead maintenance to clear clogging in the jet nozzles. In addition, there is a need for ink compositions which, when employed in thermal ink jet printing processes, exhibit large spot size and excellent optical density. Further, a need remains for ink compositions which, when employed in thermal ink jet printing processes, exhibit reduced misdirectionality of drops, thereby improving accuracy of ink placement on the recording medium. There is also a need for ink compositions which, when employed in thermal ink jet printing processes, exhibit improved print quality as a result of increased ink drop velocity. Additionally, there is a need for ink compositions which, when employed in thermal ink jet printing processes, exhibit stable long-term drop velocity and steady transit time.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide ink jet compositions and processes with the above advantages.
It is another object of the present invention to provide ink compositions particularly suitable for use in thermal ink jet printing processes.
It is yet another object of the present invention to provide ink compositions which, when employed in thermal ink jet printing processes, exhibit increased drop size, drop mass, and drop volume.
It is still another object of the present invention to provide ink compositions which, when employed in thermal ink jet printing processes, exhibit uniform drop speed over varying frequencies.
Another object of the present invention is to provide ink compositions which, when employed in thermal ink jet printing processes, exhibit high ink drop velocity or short transit time.
Yet another object of the present invention is to provide ink compositions which, when employed in thermal ink jet printing processes, exhibit a high jetting momentum, which is beneficial for printhead maintenance to clear clogging in the jet nozzles.
Still another object of the present invention is to provide ink compositions which, when employed in thermal ink jet printing processes, exhibit large spot size and excellent optical density.
It is another object of the present invention to provide ink compositions which, when employed in thermal ink jet printing processes, exhibit reduced misdirectionality of drops, thereby improving accuracy of ink placement on the recording medium.
It is yet another object of the present invention to provide ink compositions which, when employed in thermal ink jet printing processes, exhibit improved print quality as a result of increased ink drop velocity.
It is still another object of the present invention to provide ink compositions which, when employed in thermal ink jet printing processes, exhibit stable long-term drop velocity and steady transit time.
These and other objects of the present invention (or specific embodiments thereof) can be achieved by providing a thermal ink jet printing process which comprises (a) incorporating into a thermal ink jet printer an ink composition comprising water, a dye, and pigment particles having an average particle diameter of from about 0.001 micron to about 10 microns, said pigment particles being present in the ink in an amount of less than 0.1 percent by weight; and (b) causing droplets of the ink to be ejected in an imagewise pattern onto a recording medium by selectively heating the ink in the printer in an imagewise pattern, thereby generating images on the recording medium.
BRIEF DESCRIPTION OF THE DRAWING
Illustrated schematically in FIG. 1 are test results showing transit time as a function of the number of drops jetted for an ink of the present invention when jetted from a thermal ink jet printhead.
DETAILED DESCRIPTION OF THE INVENTION
The liquid vehicle of the inks employed in the present invention can consist solely of water, or it can comprise a mixture of water and a water soluble or water miscible organic component, which typically functions as a humectant. Examples of suitable organic components include ethylene glycol, propylene glycol, diethylene glycol, glycerine, dipropylene glycol, polyethylene glycols, polypropylene glycols, trimethylolpropane, amides, including N,N-dimethylformamide and other aliphatic amides, cyclic amides such as N-methylpyrrolidone and 1-cyclohexyl-2-pyrrolidone and the like, as well as aromatic amides, ethers, including dialkyl glycolethers and monoalkyl glycolethers, as well as amine derivatives such as morpholine, trimethylamine, triethylamine, dibutylamine, N,N-bis(3-aminopropyl) ethylenediamine, dialkylamines, piperidine, pyridine, and the like, carboxylic acids and their salts, esters, alcohols, including 1-propanol, 1-butanol, benzyl alcohol, phenol derivatives, and the like, organosulfides, organosulfoxides, including dimethyl sulfoxide, dialkylsulfoxides, sulfones, diarkylsulfones, sulofane, and the like, alcohol derivatives, hydroxyether derivatives such as carbitols (including 2-(2-butoxyethoxy)ethanol, 2-(2-ethoxyethoxy)ethanol, 2-(2-methoxyethoxy)ethanol, 2-(2-propoxyethoxy)ethanol), propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monobutyl ether, and the like, cellusolves, such as 2-butoxyethanol and 2-pentoxyethanol, amino alcohols, including diethanolamine, triethanolamine, and the like, ketones, polyelectrolytes, urea derivatives, and other water soluble or water miscible materials, as well as mixtures thereof. When mixtures of water and water soluble or miscible organic components are selected as the liquid vehicle, the water to organic ratio typically ranges from about 100:0 to about 40:60, and preferably from about 97:3 to about 50:50. The non-water component of the liquid vehicle generally serves as a humectant which has a boiling point usually higher than that of water (100° C.). In the ink compositions for the present invention, the liquid vehicle is typically present in an amount of from about 80 to about 99.9 percent by weight of the ink, and preferably from about 90 to about 99 percent by weight of the ink, although the amount can be outside these ranges.
The ink composition also contains a dye colorant. Any suitable dye or mixture of dyes compatible with the ink liquid vehicle can be used, with water soluble anionic dyes and cationic dyes being preferred. Examples of suitable dyes include Food dyes such as Food Black No. 1, Food Black No. 2, Food Red No. 40, Food Blue No. 1, Food Yellow No. 7, and the like, FD & C dyes, Acid Black dyes (No. 1, 7, 9, 24, 26, 48, 52, 58, 60, 61,63, 92, 107, 109, 118, 119, 131, 140, 155, 156, 172, 194, and the like), Acid Red dyes (No. 1, 8, 32, 35, 37, 52, 57, 92, 115, 119, 154, 249, 254, 256, and the like), Acid Blue dyes (No. 1, 7, 9, 25, 40, 45, 62, 78, 80, 92, 102, 104, 113, 117, 127, 158, 175, 183, 193, 209, and the like), Acid Yellow dyes (No. 3, 7, 17, 19, 23, 25, 29, 38, 42, 49, 59, 61, 72, 73, 114, 128, 151, and the like), Direct Black dyes (No. 4, 14, 17, 22, 27, 38, 51, 112, 117, 154, 168, and the like), Direct Blue dyes (No. 1, 6, 8, 14, 15, 25, 71, 76, 78, 80, 86, 90, 106, 108, 123, 163, 165, 199, 226, and the like), Direct Red dyes (No. 1, 2, 16, 23, 24, 28, 39, 62, 72, 236, and the like), Direct Yellow dyes (No. 4, 11, 12, 27, 28, 33, 34, 39, 50, 58, 86, 100, 106, 107, 118, 127, 132, 142, 157, and the like), anthraquinone dyes, monoazo dyes, disazo dyes, phthalocyanine derivatives, including various phthalocyanine sulfonate salts, aza [18] annulenes, formazan copper complexes, triphenodioxazines, Bernacid Red 2BMN; Pontamine Brilliant Bond Blue A; Pontamine; Caro direct Turquoise FBL Supra Conc. (Direct Blue 199), available from Carolina Color and Chemical; Special Fast Turquoise 8GL Liquid (Direct Blue 86), available from Mobay Chemical; Intrabond Liquid Turquoise GLL (Direct Blue 86), available from Crompton and Knowles; Cibracron Brilliant Red 38-A (Reactive Red 4), available from Aldrich Chemical; Drimarene Brilliant Red X-2B (Reactive Red 56), available from Pylam, Inc.; Levafix Brilliant Red E- 4B, available from Mobay Chemical; Levafix Brilliant Red E-6BA, available from Mobay Chemical; Procion Red H8B (Reactive Red 31), available from ICI America; Pylam Certified D&C Red #28 (Acid Red 92), available from Pylam; Direct Brilliant Pink B Ground Crude, available from Crompton & Knowles; Cartasol Yellow GTF Presscake, available from Sandoz, Inc.; Tartrazine Extra Conc. (FD&C Yellow #5, Acid Yellow 23), available from Sandoz; Carodirect Yellow RL (Direct Yellow 86), available from Carolina Color and Chemical; Cartasol Yellow GTF Liquid Special 110, available from Sandoz, Inc.; D&C Yellow #10 (Acid Yellow 3), available from Tricon; Yellow Shade 16948, available from Tricon, Basacid Black X34, available from BASF, Carta Black 2GT, available from Sandoz, Inc.; Neozapon Red 492 (BASF); Orasol Red G (Ciba-Geigy); Direct Brilliant Pink B (Crompton-Knolls); Aizen Spilon Red C-BH (Hodogaya Chemical Company); Kayanol Red 3BL (Nippon Kayaku Company); Levanol Brilliant Red 3BW (Mobay Chemical Company); Levaderm Lemon Yellow (Mobay Chemical Company); Spirit Fast Yellow 3G; Aizen Spilon Yellow C-GNH (Hodogaya Chemical Company); Sirius Supra Yellow GD 167; Cartasol Brilliant Yellow 4GF (Sandoz); Pergasol Yellow CGP (Ciba-Geigy); Orasol Black RL (Ciba-Geigy); Orasol Black RLP (Ciba-Geigy); Savinyl Black RLS (Sandoz); Dermacarbon 2GT (Sandoz); Pyrazol Black BG (ICI); Morfast Black Conc A (Morton-Thiokol); Diazol Black RN Quad (ICI); Orasol Blue GN (Ciba-Geigy); Savinyl Blue GLS (Sandoz); Luxol Blue MBSN (Morton-Thiokol); Sevron Blue 5GMF (ICI); Basacid Blue 750 (BASF); Bernacid Red, available from Berncolors, Poughkeepsie, N.Y.; Pontamine Brilliant Bond Blue; Berncolor A. Y. 34; Telon Fast Yellow 4GL-175; BASF Basacid Black SE 0228; the Pro-Jet® series of dyes available from ICI, including Pro-Jet® Yellow I (Direct Yellow 86), Pro-Jet® Magenta I (Acid Red 249), Pro-Jet® Cyan I (Direct Blue 199), Pro-Jet® Black I (Direct Black 168), Pro-Jet® Yellow 1-G (Direct Yellow 132), Aminyl Brilliant Red F-B, available from Sumitomo Chemical Company (Japan), the Duasyn® line of "salt-free" dyes available from Hoechst, such as Duasyn® Direct Black HEF-SF (Direct Black 168), Duasyn® Black RL-SF (Reactive Black 31), Duasyn® Direct Yellow 6G-SF VP216 (Direct Yellow 157), Duasyn® Brilliant Yellow GL-SF VP220 (Reactive Yellow 37), Duasyn® Acid Yellow XX-SF LP413 (Acid Yellow 23), Duasyn® Brilliant Red F3B-SF VP218 (Reactive Red 180), Duasyn® Rhodamine B-SF VP353 (Acid Red 52), Duasyn® Direct Turquoise Blue FRL-SF VP368 (Direct Blue 199), Duasyn® Acid Blue AE-SF VP344 (Acid Blue 9), various Reactive dyes, including Reactive Black dyes, Reactive Blue dyes, Reactive Red dyes, Reactive Yellow dyes, and the like, as well as mixtures thereof. The dye is present in the ink composition in any effective amount, typically from about 0.5 to about 15 percent by weight, and preferably from about 1 to about 10 percent by weight, and more preferably from about 1 to about 6 percent by weight, although the amount can be outside of these ranges.
Also contained in the ink composition of the present invention are pigment particles. The pigment can be of any desired color, such as black, cyan, magenta, yellow, red, blue, green, brown, or the like, as well as mixtures thereof. Preferably, the color of the pigment particles either is similar to or the same as the color of the selected dye, or does not interfere with or impair the desired color of the final ink. Examples of suitable pigments include various carbon blacks such as channel black, furnace black, lamp black, Raven®5250, Raven®5750, Raven®3500 and other similar carbon black products available from Columbia Company, Regal®330, Black Pearl® L, Black Pearl®1300, and other similar carbon black products available from Cabot Company, Degussa carbon blacks such as Color Black® series, Special Black® series, Printtex® series and Derussol® carbon black dispersions available from Degussa Company, Hostafine® series such as Hostafine® Yellow GR (Pigment 13), Hostafine® Yellow (Pigment 83), Hostafine® Red FRLL (Pigment Red 9), Hostafine® Rubine F6B (Pigment 184 ), Hostafine® Blue 2G (Pigment Blue 15:3), Hostafine® Black T (Pigment Black 7), and Hostafine® Black TS (Pigment Black 7), available from Hoechst Celanese Corporation, Normandy Magenta RD-2400 (Paul Uhlich), Paliogen Violet 5100 (BASF), Paliogen Violet 5890 (BASF), Permanent Violet VT2645 (Paul Uhlich), Heliogen Green L8730 (BASF), Argyle Green XP-111-S (Paul Uhlich), Brilliant Green Toner GR 0991 (Paul Uhlich), Heliogen Blue L6900, L7020 (BASF), Heliogen Blue D6840, D7080 (BASF), Sudan Blue OS (BASF), PV Fast Blue B2G01 (American Hoechst), Irgalite Blue BCA (Ciba-Geigy), Paliogen Blue 6470 (BASF), Sudan III (Matheson, Coleman, Bell), Sudan II (Matheson, Coleman, Bell), Sudan IV (Matheson, Coleman, Bell), Sudan Orange G (Aldrich), Sudan Orange 220 (BASF), Paliogen Orange 3040 (BASF), Ortho Orange OR 2673 (Paul Uhlich), Paliogen Yellow 152, 1560 (BASF), Lithol Fast Yellow 0991K (BASF), Paliotol Yellow 1840 (BASF), Novoperm Yellow FG 1 (Hoechst), Permanent Yellow YE 0305 (Paul Uhlich), Lumogen Yellow D0790 (BASF), Suco-Gelb L1250 (BASF), Suco-Yellow D1355 (BASF), Hostaperm Pink E (American Hoechst), Fanal Pink D4830 (BASF), Cinquasia Magenta (DuPont), Lithol Scarlet D3700 (BASF), Toluidine Red (Aldrich), Scarlet for Thermoplast NSD PS PA (Ugine Kuhlmann of Canada), E. D. Toluidine Red (Aldrich), Lithol Rubine Toner (Paul Uhlich), Lithol Scarlet 4440 (BASF), Bon Red C (Dominion Color Company), Royal Brilliant Red RD-8192 (Paul Uhlich), Oracet Pink RF (Ciba-Geigy), Paliogen Red 3871K (BASF), Paliogen Red 3340 (BASF), and Lithol Fast Scarlet L4300 (BASF). Other pigments can also be selected. Particularly preferred pigment particles are nonmutagenic and nontoxic carbon black particles with a polyaromatic hydrocarbon content of less than about 1 part per million. The pigment particles may be used in their commercially available forms, such as stabilized aqueous pigment dispersions, and need not be treated or modified with dispersing agents or other materials. However, if desired, a dispersing agent, dispersant, surfactant, or wetting agent can also be employed to modify the pigment dispersions further to enhance the colloidal stability of the pigment in the ink. If a pigment is not previously treated by a dispersing agent or by chemical bonding with a component (chemically modified or grafted pigment) which is hydrophilic for effectively dispersing the pigment in an aqueous system, such as a sulfonic acid salt, a phosphoric acid salt, a carboxylic acid salt, or the like, as described in, for example, U.S. Pat. No. 5,281,261, the disclosure of which is totally incorporated herein by reference, treatment of the pigment with a dispersing agent may be needed for the pigment particles to be dispersed effectively in an aqueous ink system without settling or coagulation.
A pigment dispersion can be prepared by, for example, treating pigment particles with a particle size reduction process which utilizes ball milling, homogenization, sonification, or a combination thereof in the presence of water and, if desired, at least one dispersing agent. The dispersing agent or agents can be nonionic, anionic, cationic, or amphoteric, or a combination thereof. Suitable dispersing agents, surfactants, and wetting agents include Igepal® series surfactants, alkyl or dialkyl phenoxy poly(ethyleneoxy)ethanol derivatives including Igepal® CA630, Igepal® CA-720, Igepal® CO-720, Igepal® CO-890, Igepal® CA-897, Igepal® CO-970, Igepal®DM-970, all available from Rhone-Poulenc Company, copolymers of naphthalene sulfonic salts and formaldehyde, including Daxad® 11, Daxad® 11 KLS, Daxad® 19, Daxad® 19K, and the like, all available from W. R. Grace & Company, the Lomar® series (including Lomar® D and the like), available from Diamond Shamrock Corporation, the Tamol series (including Tamol® SN and the like), available from Rohm and Haas Company, the Triton® series (including Triton® X-100, Triton® X-102, Triton® X-114, Triton® CF 21, Triton® CF 10, and the like), all available from Rohm and Haas Company, Duponol® ME Dry, Duponol® WN, Merpol® RA, Merpol® SE, Merpol® SH, Merpol® A, Zelec® NK, and the like, all available from E. I. Du Pont de Nemours & Company, the Tergitol® series, available from Union Carbide Company, the Surfynol® series (GA, TG, 465H, CT-136, and the like), available from Air Products and Chemicals Co., copolymers of styrene and maleic acid salts, such as those available from Alco Chemical Inc., polyacrylate derivatives, copolymers of acrylic monomers or methacrylic monomers and their salts, polystyrenesulfonate salts, and the like, as well as mixtures thereof. The dispersing agent is typically present in an amount of from about 0.1 to about 150 percent by weight of the pigment, and preferably from about 1 to about 100 percent by weight of the pigment, although the amount can be outside these ranges.
The pigment particles typically have an average particle diameter of from about 0.001 micron (1 nanometer) to about 10 microns, preferably from about 0.01 micron (10 nanometers) to about 3 microns, although the particle size can be outside this range. Reduction of pigment particle size can be achieved by various processes, such as ball milling, roll milling, paintshaking, mechanical attrition, microfluidization in a liquid jet interaction chamber at a high liquid pressure, sonification, precipitation, acid pasting, and the like. It is preferred to reduce the size of the pigment particles in the presence of water and a dispersing agent for the preparation of a pigment dispersion. The pigment particles treated with the dispersing agent form a stable colloidal pigment dispersion. The pigment dispersion can then be used to prepare a pigmented ink in an aqueous medium comprising a liquid vehicle, the pigment dispersion, and any additional desired ink additives. If necessary, additional steps of centrifugation and filtration can be carried out to assure the maintainenance of good pigment particle size in the ink after mixing the ink ingredients together. The ink or the pigment dispersion (higher pigment concentration) can then be admixed with a dye. The pigment particles can be added to an ink jet ink which comprises water, a dye, an optional humectant, an optional biocide, an optional pH buffer agent, an optional chelating agent, an optional penetrant or drying accelerating agent for decreasing drying time, an optional antioxidant, an optional anticlogging agent, and an optional monomeric or polymeric additive with thorough mixing. If necessary, a filtration process can be carried out to remove large or unstable pigment particles. Alternatively, pigment particles which are prepared by a chemical modification method or a grafting technique for providing needed hydrophilicity can also be employed. These modified or grafted pigment particles usually comprise a copolymer or polymer which contains either an ionizable component in water or a water miscible component to provide good colloidal stability in an aqueous ink.
The pigment particles are present in the ink in an amount of less than about 0.1 percent by weight of the ink, preferably from about 1 part per billion (0.0000001 percent) by weight to about 900 parts per million (0.09 percent) by weight, and more preferably from about 1 part per billion (0.0000001 percent) by weight to about 750 parts per million (0.075 percent) by weight of the ink.
Polymeric additives can also be added to the inks of the present invention to enhance the viscosity of the ink composition and provide any other desired functions. Water soluble polymers such as Gum Arabic, polyacrylate salts, polymethacrylate salts, polyvinyl alcohols, polyethylene oxides, poyethylene glycols, polypropylene glycols, hydroxypropylcellulose, hydroxyethylcellulose, polyvinylpyrrolidinone, polyvinylether, starch, polyacrylamide, copolymers of naphthalene sulfonate salts and formaldehyde, polysaccharides, and the like are particularly useful for stabilizing pigment particles in a water based liquid vehicle such as water or a mixture of water and a water soluble organic component. Polymeric additives, if present, can be present in the ink composition of the present invention in any effective amount, typically from 0 to about 5 percent by weight of the ink, and preferably from about 0.001 to about 3 percent by weight of the ink, although the amount can be outside these ranges.
Other optional additives to the ink composition of the present invention include biocides, such as Dowicil® 150, 200, and 75, Omidines® (Olin Company), benzoate salts, sorbate salts, and the like, typically present in an amount of from about 0.0001 to about 4 percent by weight, and preferably from about 0.01 to about 2.0 percent by weight, although the amount can be outside these ranges, antioxidants, including derivatives of phenols such as BHT, 2,6-di-t-butylphenol, and the like, tocopherol derivatives such as Vitamin E and the like, aromatic amines, alkyl and aromatic sulfides, and the like, typically present in an amount of from 0 to about 10 percent by weight, and preferably from 0 to about 5 percent by weight, although the amount can be outside these ranges, pH controlling agents, including acids such as acetic acid, phosphoric acid, boric acid, sulfuric acid, nitric acid, hydrochloric acid, and the like, bases such as potassium hydroxide, sodium hydroxide, lithium hydroxide, ammonium hydroxide, trimethylamine, ethanolamine, morpholine, triethanolamine, diethanolamine, and the like, phosphate salts, carboxylate salts, sulfite salts, amine salts, and the like, typically present in an amount of from 0 to about 10 percent by weight, and preferably from about 0.001 to about 5 percent by weight, although the amount can be outside these ranges, drying accelerating agents, such as sodium lauryl sulfate, N,N-diethyl-m-toluamide, cyclohexylpyrrolidinone, butylcarbitol, benzyl alcohol, polyglycol ethers, and the like, typically present in an amount of from about 0.001 to about 25 percent by weight, and preferably from about 0.01 to about 3 percent by weight, although the amount can be outside these ranges, surface tension modifiers, including surfactants such as sodium lauryl sulfate, sodium dodecyl sulfate, sodium octyl sulfate, Igepal® CO-630, Igepal® CO-530, Igepal® CA-630, Igepal® CA-530, and the like, typically present in an amount of from 0 to about 10 percent by weight, and preferably from 0 to about 5 percent by weight, although the amount can be outside these ranges, ink penetrants, such as alcohols, including isopropanol, butyl alcohol, and the like, sodium lauryl sulfate, esters, ketones, polyethylene glycol ether derivatives, N-methylpyrrolidone, and the like, typically present in an amount of from about 0.001 to about 15 percent by weight, and preferably from about 0.001 to about 10 percent by weight, although the amount can be outside these ranges, chelating agents, including EDTA (ethylene diamine tetraacetic acid), HEEDTA (N-(hydroxyethyl) ethylenediaminetriacetate), NTA (nitriloacetate), DTPA (diethylenetriaminepentaacetic acid), and the like, as well as their salts, typically present in an amount of from about 0.001 to about 5 percent by weight, and preferably from about 0.001 to about 2 percent by weight, although the amount can be outside these ranges, and additives for improving waterfastness and lightfastness, such as polyethyleneimine, ethylene and propylene oxide modified polyethyleneimine, and the like, typically present in an amount of from 0 to about 10 percent by weight, and preferably from 0 to about 5 percent by weight, although the amount can be outside these ranges. The viscosity of the ink typically is from about 1 to about 10 centipoise (measured at 25° C.) and preferably is less than about 4 centipoise, although the viscosity can be outside these ranges.
The ink jet inks of the present invention can be formulated to have either slow drying or fast drying characteristics on plain papers. The slow drying inks typically have a drying time greater than about 1 second, whereas the fast drying inks typically have a drying time of less than about 1 second. The surface tension of an ink of the present invention typically has a range of from about 26 to about 72 dynes per centimeter at 23° C., although the surface tension can be outside this range. The surface tension of a slow drying ink at 23° C. typically is equal to or greater than about 45 dynes per centimeter, and the surface tension of a fast drying ink at 23° C. typically is lower than about 45 dynes per centimeter. During the printing process, a heating means, such as a heated platen, a heated drum, a heated belt, a heated lamp, a microwave dryer, or the like can be used, if desired, to heat the recording medium (substrate or sheet) at any desired printing stages such as before printing, during printing, after printing, or some combination thereof to increase ink drying rates and to avoid ink smearing and intercolor bleeding. The recording medium usually is a plain paper, a coated paper, or an ink jet transparency, although other media can also be employed.
Generally, it is preferred to formulate the inks of the present invention to exhibit a reasonable level of resistivity or conductivity. Highly conductive ink jet inks can cause unwanted or premature heater damage, corrosion, ink instability, and nozzle clogging in a printhead. For these reasons, the resistivity of the inks of the present invention is preferably greater than about 142.86 Ohm-cm at room temperature. The conductivity of the ink containing a small amount of pigment particles is preferred to be less than about 7000 microMho/cm (or 0.007000 (Ohm-cm) -1 ) at room temperature.
Inks of the present invention can be prepared by any process suitable for preparing aqueous inks. An ink of the present invention can be prepared by thoroughly admixing water, an optional organic component (e.g. humectant), a pigment or pigment dispersion, an optional dispersant, an optional biocide, and any other desired optional additives. It is preferred, but not necessary, to prepare two inks of identical composition except that one contains a pigment and one contains a dye. The addition of a small amount of pigmented ink to the dye-based ink will not cause a significant change in the overall composition of the dye-based ink (except for a small change in the dye concentration) in the modification process. Also, in this way pigment particles in the pigmented ink will not experience a colloidal shock or instability when they are added to the dye-based ink of similar composition. The pigmented ink can be added slowly to the dye-based ink in the desired relative amounts with thorough mixing and stirring until a uniform ink composition results (typically about 30 minutes, although the mixing/stirring time can be either greater or less than this period). While not required, the ink ingredients can be heated during mixing or stirring if desired. Subsequent to mixing and stirring, the ink composition can be used either with or without filtration.
The process of the present invention can be employed with a wide variety of recording media, including plain papers such as Xerox® 4024 papers, including Ashdown 4024 DP, Cortland 4024 DP, Champion 4024 DP, Xerox® 4024 D.P. green, Xerox® 4024 D.P. pink, Xerox® 4024 D.P yellow, and the like, Xerox® 4200 papers, Xerox® 10 series paper, Xerox® Imaging Series LX paper, canary ruled paper, ruled notebook paper, bond paper such as Gilbert 25 percent cotton bond paper, Gilbert 100 percent cotton bond paper, and Strathmore bond paper, recycled papers, silica coated papers such as Sharp Company silica coated paper, JuJo® paper, glossy papers, and the like, transparency materials such as Xerox® 3R3351 ink jet transparencies, Tetronix ink jet transparencies, Arkright ink jet transparencies, Hewlett-Packard ink jet transparencies, and the like, fabrics, textile products, plastics, polymeric films, inorganic substrates such as metals and wood, and the like.
The jetting performance of the ink jet inks of the present invention were tested with either a 300 SPI (300 dpi) or 400 SPI (400 dpi) printhead with a 3 microsecond pulse length at a frequency of 1 KHz. The operating voltage for the printhead was held in a range of from 30 to 50 volts. The operating voltage generally was about 10 percent over the threshold voltage (minimum voltage needed to cause ejection of an ink droplet) of the printhead and the exact operating voltage used for the printhead in each instance depended on the ink and the type of printhead used. Ink drop mass (related to drop volume), transit time for a drop of ink travelling to a distance of 0.5 mm (related to drop velocity), and jetting stability were measured. The ink drop mass was determined by measuring the weight of collected ink divided by the number of drops of ink jetted. Ink velocity was calculated from the transit time data with the following formula (0.0005 meter/transit time). Thus, for an ink with a transit time of 50 microseconds, the ink drop velocity is 10 meters per second. A fast ink drop velocity (or short transit time over a fixed distance) usually results in accurate placement of the ink on a recording medium or substrate and a reduced directionality problem. A jetted ink with a large momentum (mass times velocity) enables easier removal of a solid or a viscous liquid plug near the orifice of an ink jet printhead, thus improving jetting efficiency and avoiding missing jets or misdirectionality problems. A large drop mass or drop volume of the jetted ink tends to produce a large spot on a recording medium to give high optical density and good image quality. For ink jet printing with a resolution of 300 SPI, a drop mass of about 140±20 nanograms per drop may be desired for a black ink to enable good optical density on a plain paper.
The ink of the present invention comprises a small amount of pigment particles well dispersed in an ink jet ink containing a dye. The pigment particles can be deposited uniformly onto a heater of a printhead and improve the nucleation, evaporation, and bubble formation of the ink ingredients, particularly the water (B.P.=100° C.), during thermal ink jet printing processes. The ink of the present invention exhibits an increase in drop mass (drop volume), drop velocity (short transit time), and long-term jetting stability for ink velocity (or transit time) compared to dye-based inks of similar composition but containing no pigment particles. As a result, the ink of the present invention enables proper placement on the recording medium with large spot size and very good optical density, and reduces misdirectionarity problems. Furthermore, upon jetting, the ink of the present invention possesses a large momentum, which can facilitate the removal of possible ink clogging near the nozzles of the printhead, and thus improves printhead maintenance efficiency. Also, long-term jetting stability (drop velocity, drop mass, and the like) are improved for the inks of the present invention, and the inks allow a printhead to function properly over a long period of time with good jetting performance.
The inks of the present invention can, if desired, be employed in a thermal ink jet printhead comprising multiple heaters and nozzles (for example, 48 jets, 128 jets, 192 jets, 256 jets, or the like) for printing on a recording medium with good image resolution of, for example, from 200 to 800 spots per inch. The multiple jet printheads can also be butted together in a series to form a printhead (full-width array printhead) capable of printing the ink imagewise on a recording medium at a faster speed than conventional (e.g. linewise printing) printheads.
Specific embodiments of the invention will now be described in detail. These examples are intended to be illustrative, and the invention is not limited to the materials, conditions, or process parameters set forth in these embodiments. All parts and percentages are by weight unless otherwise indicated.
EXAMPLE I (COMPARATIVE)
A black ink was prepared by admixing BASF X-34 dye (40.32 grams dye concentrate containing 12.096 grams dye solids), ethylene glycol (70.0 grams), isopropanol (12.35 grams), Dowicil 200 biocide (0.35 gram), and distilled water (226.98 grams). The pH of the ink was adjusted to 7.0. The ink was then filtered through 5.0 and 1.2 micron filters. The surface tension of the ink was 48.8 dynes per centimeter and the viscosity of the ink at room temperature was 2.0 centipoises. The conductivity of the ink at room temperature was 0.0035 (ohm-cm)- 1 .
EXAMPLE II
A carbon black pigment dispersion was prepared by adding Raven® 5250 carbon black (60 grams), Lomar® D solution (15 grams of Lomar® D in 60 grams of water), and distilled water (175 grams) to an attritor (O1 size from Union process Inc.) containing 1500 grams of stainless steel shots and milling for 30 minutes. After removing most of the carbon black dispersion from the attritor, additional water was added to the attritor in three portions (3×25 grams of distilled water) with mixing to repeatedly extract more carbon black dispersion from the attritor. All carbon black dispersions were combined to form a homogeneous pigment dispersion (353.76 grams, 16.86 percent by weight carbon black).
A carbon black ink was then prepared by thorough admixing of the above carbon black dispersion (74.14 grams), distilled water (116.8 grams), Dowicil 200 (0.25 gram), isopropanol (8.75 grams), and ethylene glycol (50.0 grams). The mixture was adjusted to pH=7.8, sonified, and centrifuged (7000 RPM). Liquid carbon black ink was then separated from unsuspended solid residue and filtered through a series of filters with pore sizes of 5.0 microns, 3.0 microns, and 1.2 microns. The resulting ink contained about 4.3 percent by weight carbon black with a particle size of less than 1.2 microns. The surface tension and viscosity of the ink at room temperature was dynes per centimeter and the viscosity at room temperature was 2.22 centipoises. The conductivity of the ink was 0.0050 (ohm-cm)- 1 .
EXAMPLE III
Several inks were prepared comprising a dye and different concentrations of pigment particles. Different amounts of the dye-based ink (Example I) and the pigmented ink (Example II) were weighed and thoroughly mixed to yield ink jet inks containing a) 0.025 percent by weight carbon black (Example IIIA); b) 0.05 percent by weight carbon black (Example IIIB); c) 0.075 percent by weight carbon black (Example IIIC); d) 0.09997 percent by weight carbon black (Example IIID); and e) 0.04 percent by weight carbon black (Example IIIE). All of the inks in Example III (A to E) were of similar composition except for the level of pigment concentration. All of the inks exhibited surface tensions in the range of 48.5 to 50.1 dynes per centimeter at room temperature, viscosities of from 2.0 to 2.3 centipoises at room temperature, and conductivities of less than 0.0045 (Ohm-cm)- 1 The transit times for ink droplets to travel a distance of 0.5 millimeter were 80 microseconds or more for the unmodified ink (Example I) and 58 microseconds or less for the modified inks (Examples IIIA, B, C, D, and E). These results demonstrate that the modified inks jetted at a higher velocity than the unmodified ink. Further data for the unmodified and modified inks is provided in Table I, showing increased drop mass data of modified dye inks containing pigment particles. Ink IIIE was also used in the long-term jetting stability test (Example V).
______________________________________ amount of amount of pigmented ink dye-based ink % by wt. drop mass of Example II of Example I pigment (nanogramsInk (grams) (grams) in ink per drop)______________________________________I 0.0 60.0 0 94-115IIIA 0.350 59.65 0.025 148IIIB 0.702 59.36 0.050 149IIIC 1.048 58.96 0.075 155IIID 1.390 58.61 0.0999 156______________________________________ Testing printhead was 300 SPI operated at 38 volts with a 3 microsecond pulse length at room temperature.
EXAMPLE IV
Additional inks were prepared by admixing the ink of Example I with the ink of Example II in varying amounts to yield inks containing a) 25 ppm carbon black (0.0025 percent by weight, Example IVA); b) 50 ppm carbon black (0.0050 percent by weight, Example IVB); and c) 100 ppm carbon black (0.0100 percent by weight, Example IVC). All of the inks exhibited conductivities of less than 0.0045 (Ohm-cm)- 1 . A 300 SPI printhead was employed for the jetting test to measure the average drop mass per drop of ink. All of the inks (Examples IV A, B, and C) exhibited larger drop mass than the ink of Example I. Some of the results are shown below in Table II, showing the effect of a small amount of pigment particles on drop mass in dye-based inks.
______________________________________ pigment drop mass increase in drop concentration (nanograms mass (nanogramsInk (ppm) per drop) per drop)______________________________________I 0 96 0IVA 25 102 8IVB 50 107 11IVC 100 120 24______________________________________
EXAMPLE V
The inks of Example I and Example IIIE were tested for long-term jetting stability with a 400 SPI printhead which was operated at 41 volts with a 3 microsecond pulse length. The results are shown in FIG. I, which shows transit time data (time for a travelling distance of 0.5 millimeters) as a function of number of jetting drops for the ink of Example (containing no pigment particles) and Example IIIE (containing 0.04% pigment particles). As the data in FIG. I indicate, the ink according to the present invention exhibits better long-term jetting stability and drop velocity (steady and shorter transit time with faster drop velocity) compared to the ink of Example I for up to at least 1×1 7 pulses. In addition, the ink of the present invention also yielded larger ink drop mass or drop volume than the ink of Example I.
EXAMPLE VI
A pigment dispersion was prepared as described in Example II except Lomar D (an anionic dispersant, 15 grams) was replaced with Igepal CO-890 (a nonionic dispersant, 18 grams). The fabricated pigment dispersion (361 grams) contained 15.39 percent by weight carbon black. A pigmented ink was then prepared by thoroughly admixing the pigment dispersion (97.53 grams), distilled water (131.67 grams), ethylene glycol (60.0 grams), Dowicil 200 (0.3 gram), and isopropanol (10.5 grams) with sonification. The ink mixture was adjusted to pH=7.37 and centrifuged at a speed of 10,000 RPM, followed by filtration with a series of filters with sizes of 5.0 microns, 3.0 microns, and 0.65 micron to yield a pigmented ink containing 20 percent by weight ethylene glycol, 3.5 percent by weight isopropanol, 4.02 percent by weight carbon black pigment particles, 0.1 percent by weight Dowicil 200, and distilled water (balance).
EXAMPLE VII
An ink was prepared by admixing the dye-based ink of Example I (99.004 grams) and the pigmented ink of Example VI (0.996 gram) to yield an ink containing 0.04 percent by weight carbon black pigment. The ink had the following physical properties at room temperature (23° C.): pH=7.48, viscosity=2.3 centipoises, conductivity=0.0040 (Ohm-cm)- 1 , and surface tension 47.2 dynes per centimeter. The ink was tested with a 300 SPI thermal ink jet printhead and exhibited a drop mass of 145 nanograms per drop, compared to a drop mass of 94 nanograms per drop for the ink of Example I.
EXAMPLE VIII
A pigmented ink was prepared by thoroughly admixing Hostafine Black TS black pigment (obtained from Hoechst Celanese Corporation, 45.45 grams), ethylene glycol (60.0 grams), isopropanol (10.5 grams), Dowicil 200 (0.3 grams), and distilled water (183.75 grams). The ink was adjusted for pH, centrifuged, and filtered with 5.0 micron, 1.2 micron, and 0.65 micron membrane filters. The pigmented ink thus prepared contained 6.0 percent by weight solids. The aforementioned pigmented ink (0.523 gram) was added to the dye-based ink of Example I (99.497 grams) with thorough mixing to yield an ink containing 0.0314 percent by weight solids (including carbon black and dispersing agent). The ink thus prepared exhibited the following physical properties: surface tension=47.2 dynes per centimeter, pH=7.48, conductivity=4100 (microOhm-cm)- 1 , and viscosity=2.3 centipoises. The ink had a drop mass of 104 nanograms per drop, which is larger than the drop mass of the ink of Example I (94 nanograms per drop).
EXAMPLE IX
The dye-based ink of Example I (79.25 grams) was admixed with the pigmented ink of Example II (0.744 gram) to yield an ink containing 0.04 percent by weight pigment particles. The ink thus prepared (60 grams) was placed in an ink cartridge with a 128 jet printhead, polyester felts, a scavenger consisting of polyurethane foam and a polyester microfilter, a heat sink, and necessary electrical connections. After priming, the cartridge was tested on a test fixture and showed that the ink produced an average drop mass of 148 nanograms per drop (average of 128 jets). The ink cartridge containing the ink was placed in an ink jet printer (Texas Instruments MicroMarc) for printing tests. The ink was printed on several plain papers and yielded excellent print quality with high optical density and accurate ink placement with no poor directionality. The accomplishment of high optical density on plain papers indicates that the modified ink was jetted with an adequate ink drop volume (or drop mass) and spot size for complete pixel coverage. High ink drop velocity (or short transit time) allowed an accurate ink placement on the recording media. The average spot size on the Xerox® Image Series Smooth paper was about 130 microns. The optical density data of the ink on different plain papers are listed below: Xerox® Image Series LX paper: O.D.=1.31; Xerox® Image Series Smooth: O.D.=1.26; Gilbert Bond paper: O.D.=1.33; and Neenah Classic Laid paper: O.D.=1.28.
Other embodiments and modifications of the present invention may occur to those skilled in the art subsequent to a review of the information presented herein; these embodiments and modifications, as well as equivalents thereof, are also included within the scope of this invention. | Disclosed is a thermal ink jet printing process which comprises (a) incorporating into a thermal ink jet printer an ink composition comprising water, a dye, and pigment particles having an average particle diameter of from about 0.001 micron to about 10 microns, said pigment particles being present in the ink in an amount of less than 0.1 percent by weight; and (b) causing droplets of the ink to be ejected in an imagewise pattern onto a recording medium by selectively heating the ink in the printer in an imagewise pattern, thereby generating images on the recording medium. The disclosed ink is capable of producing a large drop mass, high ink velocity, good directionality, and high quality images on plain papers with excellent long-term jetting stability. | 59,970 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of renewing water service pipe as well as to an apparatus used in carrying out a part of the method wherein a coating is applied to the inner surface of the water service pipe.
2. Description of the Prior Art
With years of use, rust, scales and other contaminants are generated and stick to the inner peripheral surface of pipes. This buildup effectively reduces the diameter of the pipe, resulting in increased flow resistance to the water flow with a consequent reduction of the flow rate as well as various inconveniences resulting from the reduced flow rate.
To overcome the above problems, it becomes necessary to periodically either replace the water supply pipe or renew the pipe by removing rust, scales and other contaminants attaching to the inner surface of the water service pipe. However, replacement of the water service pipe entails extensive long-term construction, as well as great expense to municipalities and, therefore, must be carefully planned.
For this reason, in most cases, effective yet simple renewal of pipes at relatively low cost would prove very useful.
Yet, even when pipes are renewed, it is very important that the renewal be completed in a short time period because the construction inherently necessitates a suspension of the water service supply, as well as the disruption of traffic around the site.
For these reasons, there is an increasing demand for the development of a method which can effect a perfect renewal of the water pipe quickly and which can prevent the recurrence of rusting, scaling and contamination of the inner surface of the pipe for many years, once the pipe has been treated.
SUMMARY OF THE INVENTION
It is, therefore, an object of the invention to reduce the period required for renewing water pipe.
It is another object of the invention to make it possible to thoroughly remove rust, scales, and other contaminants adhering to the inner surface of a water service pipe previously in use, so as to perfectly renew the latter.
It is yet another object of the invention to coat the inner surface of a previously constructed pipe which has been freed from rust, scale and other contaminants with an anti-rust synthetic resinous paint, so as to prevent the generation and adherance of rust, scales and contaminants to the inner wall of the pipe for a long time.
It is yet a further object of the invention to provide an apparatus capable of mixing a dual component synthetic resinous liquidus paint, which comprises a main liquid and a hardening liquid which harden rapidly, when mixed with each other immediately before application, by swiftly atomizing the mixed paint onto the inner surface of the pipe, thereby ensuring the formation of a thin and uniform coating of the paint on the latter.
It is another object of the invention to provide an apparatus capable of effectively mixing the main liquid and the hardening liquid of the dual component liquidus paint without employing electric driving power.
It is yet another object of the invention to provide a compact and a simple apparatus for coating the inner surface of a pipe, which affords easy removal of hardened residual paint attaching to the inside of the apparatus, and an easy cleaning of the inside of the pipe, as well as an easy inspection and replacement of the air motor at the site.
It is a further object of the invention to provide an apparatus, for coating the inner surface of the pipe, which can be inserted into and moved through even bent and curved pipes, so as to ensure a complete coating in a simple manner not only for straight pipes but for bent and curved pipes as well.
In fulfilling the above objects, a method of renewing a pipe section having fluid flowing therethrough has now been developed which comprises stopping the fluid flow through the said section. A scrubbing element is then inserted into one end of the section. This element is advanced from one end of the section to the other end thereof while it, at the same time, ejects a cleaning fluid from the scrubbing element to clean the inside of the section of materials adhering thereto. The section is then scraped to remove materials adhering to the inside of the section which were not removed by the scrubbing element. The materials removed during the scrubbing and scraping steps are flushed from the inside of the section and the section is dried by inducing a flow of air through the section. The inside of the section is painted by passing a painting device through the inside of the section to apply a mixture of paint and hardening liquid to the inside of the section.
In a preferred embodiment of the invention, the scrubbing element is a jet nozzle and the method of the invention comprises advancing the jet nozzle through the pipe by means of the reaction force generated when pressurized water is forced through the jet nozzle.
In yet another preferred embodiment of the invention the section is dried by creating a suction within the section to induce the flow of air therethrough. This suction is preferably created by providing a hollow suction pipe having an opening of diverging inner cross-section such that the suction pipe has an end of greater inner cross-section. The suction pipe further comprises means for introducing pressurized liquid around the periphery of the end of lesser cross-section. The end of greater inner cross-section is placed in fluid communication with the inside of the pipe section and pressurized liquid is passed past the end of lesser inner cross-section of the suction pipe to create a suction within the section.
A most preferred feature of the invention is the use of heated air to dry the pipe section.
The objects of the invention are further fulfilled by the apparatus of the invention which may be used to coat the inner surface of a pipe. The apparatus comprises: a casing; an air driven motor arranged within the casing; an air passage formed in the casing for introducing air into the casing to drive the motor; a cowling shaft projecting from a first end of the casing, the shaft being adapted to be rotated by the air driven motor; a cap shaped cowling having a base wall and a peripheral wall, said peripheral wall comprising a plurality of apertures, and cowling being attached to said cowling shaft to rotate with said shaft; a paint passage having an inlet and outlet, extending the length of said casing, said outlet opening onto said first end of said casing; and a paint nozzle connected to said end of said paint passage opening onto said first end of said casing to receive paint passing therethrough, said paint nozzle comprising at least one nozzle orifice facing and spaced from the interior of said peripheral wall of said cowling.
In a preferred embodiment, the apparatus further comprises a mixing device connected to the inlet portion of the paint passage. This mixing device is adapted to mix paint and hardening liquid fed to the device to form a mixture of the two prior to introducing the mixture into the paint passage.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates scrubbing the inner surface of a pipe with the scrubbing element of the invention;
FIG. 2 illustrates scraping the inner surface of the pipe with a scraping element;
FIG. 3 illustrates cleaning the inner surface of the pipe with a mop;
FIG. 4 illustrates air drying the inside of the pipe;
FIG. 5 illustrates coating the inside of the pipe with a paint mixture;
FIG. 6 is a longitudinal cross-sectional view of a scrubbing element used in FIG. 1;
FIG. 7 is a partially cut-away side elevational view of a scraping body used in FIG. 2;
FIG. 8 is a perspective view of an alternative type of brush head for use instead of the scraping body shown in FIG. 7;
FIG. 9 is a longitudinal cross-sectional view of the device used in FIG. 4 to dry the pipe;
FIG. 10 is a cross-sectional view taken along the line I--I of FIG. 9;
FIG. 11 is a top view of the painting apparatus shown in FIG. 5;
FIG. 12 is a partially cut-away enlarged top view of the painting apparatus shown in FIG. 11;
FIG. 13 is a partially cut-away side elevational view of the apparatus shown in FIG. 11;
FIG. 14 is a side view of a painting device shown in FIG. 11, with its housing portion in cross-section;
FIG. 15 illustrates a mixing device for the painting apparatus;
FIG. 16 is a longitudinal cross-sectional view of a connector coupling;
FIG. 17 is an enlarged cross-sectional view taken along the line II--II of FIG. 14;
FIG. 18 is a sectional view taken along the line III--III of FIG. 17;
FIG. 19 is a sectional view taken along the line IV--IV of FIG. 17;
FIG. 20 is an exploded sectional view of the painting device in its disassembled state;
FIG. 21 is a sectional view taken along the line V--V of FIG. 20;
FIG. 22 is a cross-sectional view along the line VI--VI of FIG. 20; and
FIG. 23 is an longitudinal cross-sectional view of a bearing and a portion surrounding the bearing and the cowling shaft of the painting device arranged for assembly.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
To renew and clean a water service pipe, which has already been in use, the water supply to the water service area around the pipe to be renewed is first shut off. As may be seen from FIG. 1, the ground in which the water service pipe A is buried is then bored at intervals of about 100 m or the like, as illustrated at B, so as to expose the water service pipe A at each of the bores B. At each bore, a suitable length of the pipe such as 60 cm., for example, is cut away. As a result, the already-constructed water service pipe A is cut into sections, each having a length of about 100 m.
Lengths of 100 m for the pipe sections are not meant to be exclusive of other segment lengths, and the water service pipe A can be cut at intervals other than 100 m, depending on the piping arrangement, state of the road and other conditions.
After cutting the pipe A into sections of, for example, 100 m length as explained above, a guide roller 100 is attached to one end opening of the pipe section A which is to be renewed first. A scrubbing element 101 is then inserted into the pipe section A, guided by the guide roller 100.
As shown in FIG. 6, the scrubbing element 101 has a bullet-like head section 102 and a cylindrical body section 104 connected to the rear end portion of the head-section through a neck section 103. A suitable number of jet nozzle ports 105 are regularly distributed around the circumference of the neck section 103, and are directed obliquely rearwardly and radially outwardly relative to the front of the element. An adapter 107 fixed to the end of water supply tube 106 is screwed into the body section 104 of scrubbing element 101, thus connecting water supply tube 106 to scrubbing element 101.
When the size of the scrubbing element is relatively small, the screwing engagement of the adapter 107 and the body section 104 of the scrubbing element 101 is made in a manner as shown in FIG. 6, i.e., by direct engagement of these members through a thread formed on the outer periphery of adapter 107 with a thread formed on the inner periphery of the body section 104, as shown at 108.
The size of the scrubber body 101 will be a function of the diameter of the pipe A to be renewed. Thus, for the renewal of a pipe A having a large diameter, it will be necessary to use a large-sized and heavy scrubbing element. When a large-sized scrubbing element 101 is used, the connection between the body section 104 and the water supply tube 106 is made through the engagement of the adapter 107 at the end of the water supply tube 106 with an adapter nut which is itself rotatably secured to the body section 104 in a water-tight manner. In this arrangement, the scrubbing body 101 is attached to the water supply tube 106 by simply rotating the nut.
The water supply tube 106 is made of a material having the appropriate flexibility and strength, and is connected at its end to a water pressurizing apparatus C.
As pressurized water is supplied from the water pressurizing apparatus C, through the water supply tube 106, to the scrubbing element 101, the scrubbing element 101 is self-propelled by the reaction of the pressurized water being jetted obliquely rearwardly through the jet nozzle ports 105, and moves ahead through the pipe A. During the forward movement of the scrubbing body 101, incrustations, scales and other contaminants on the inner wall of the pipe A are parted from the latter, due to the pressure exerted by the body of the scrubbing element 101 which is itself moving ahead, and due to the violent jet of water being jetted from the nozzle ports 105. The freed rusts, scales and other contaminants are then washed or flushed away from the pipe A, by the rearward flow of the water.
The water pressurizing apparatus may be mounted on an automobile or like vehicle for easy movement, while the water supply pipe 106 is wound around a rotary drum 110 (FIG. 1) so that it unwinds with the forward movement of the scrubbing element 101.
The water to be supplied may be picked up from any suitable source closest to the site.
The scrubbing step performed by the scrubbing element may be carried out repeatedly, as required, depending on the extent of buildup and incrustation on the inside of pipe A. The scrubbing body 101 can be returned to the starting position by simply rewinding the rotary drum 110, and then restarting the process from that position.
It will be seen that there is no damage to the pipe or joint by removed contaminants because the rust, scales and contaminants on the pipe wall are crushed into fine particles due to the impact pressure imparted by the scrubbing element and by the application of the jetted high pressure water, and are then conveniently washed away from the inside of the pipe A. The liquid may conveniently wash the removed materials into a ditch as illustrated in FIG. 1.
Additionally, since the scrubbing element is self-propelled through the pipe A by the reaction of the high pressure water jetted therefrom through the nozzle ports, it is not necessary to provide a specific means for moving the element such as a towing rope. Therefore, the work of inserting the towing means into the pipe and other associated works, which have in the past been necessary may be eliminated with the process of the invention, thus minimizing the time required for the scrubbing.
Although most of the rust, scales and other contaminants on the pipe wall may be removed by the foregoing scrubbing step, specific substances and strongly adhering materials may still remain along the pipe wall even after scrubbing. If the inner pipe wall is subsequently coated while these substances and materials remain on the pipe wall, these substances would soon cause peeling of the paint coating. Therefore, it is necessary to completely remove adhering materials in advance of the coating step.
To this end, a scraping step may be performed subsequent to the above scrubbing step, to smooth the inner surface of the pipe, by scraping off residual substances and materials. This is done by towing and moving a scraping element 111 along the inner wall of the pipe as shown in FIG. 2.
The scraping element 111 comprises a turbine 112 and a brush head 113 adapted to be rotated by the turbine 112. As shown in FIG. 7, the turbine 112 has a housing 131. A bearing 131 supports a rotor shaft 130a formed unitarily with the housing 131. A guide ring 132 for guiding the pressurized water is fixed to the inner periphery of the housing 131. The rotor shaft 130a is rotatably secured to the center of the guide ring 132 through a roller bearing 133. An impeller 135 is fixed to the rotor shaft 130a by means of a key 134, and is positioned just in front of the guide ring 132. The guide ring 132 is fixed to the housing 131 by means of a cap 136 which is screwed into the rear end portion of the housing 131.
A plurality of inclined grooves 137 are formed in the outer peripheral surface of the guide ring 132, for directing pressurized water which is introduced into the housing through the hose 106. On the other hand, a plurality of water receiving grooves 138 are formed to extend substantially at right angle to guide grooves 137. Turbine shaft 130 comprises rotor shaft 130a carrying impeller 135 and, rotatably supported in the turbine 112, a flexible shaft 130b screwed to the end of the rotor shaft 130a and a rod 130c screwed to the end of flexible shaft 130b. Flexible shaft 130b comprises, for example, a coiled steel wire of appropriate length having nuts 139 and 140 welded to its two ends. Brush head 113 is detachably secured to rod 130c.
The brush head 113 may be a steel wire brush as shown in FIG. 7, or may comprise a governor blade as shown in FIG. 8, and has a diameter substantially equal to or slightly smaller than the diameter of the pipe to be renewed.
Once the scrubbing element 101 has been moved from the one end opening of the pipe section A where it was inserted to the other end of the pipe section, the scrubber element 101 is detached from the water supply tube 106, and the turbine 112 is then coupled to the adapter 107 of the water supply tube 106.
Then, while supplying highly pressurized water from the water pressurizer C to the water supply tube 106, the rotary drum 110 is rotated to retract the tube, thereby towing the scraping element 111 through the pipe section A. Consequently, the pressurized water supplied to the scraping element 111 through the water supply tube 106 causes the rotation of the turbine 112, to thereby rotatably drive the brush head 113 with contact of the latter with the inner peripheral wall of the pipe section A. Consequently, contaminants still sticking to the wall of the pipe section A are scraped and the wall surface is smoothed. The contaminants scraped off the wall are conveniently washed away by the water discharged into the pipe section A.
Subsequent to this scraping step, the scraping element 111 is detached from the water supply and the scrubbing element 101 may again be attached to water supply tube 106. The scrubbing element 101 is then self-driven and run along the inner wall of the pipe section A, as is the case of the aforementioned scrubbing step, so as to rinse the inside of the pipe section A and to completely wash away any residual contaminants.
Then, if necessary, the inner surface of the pipe section A is wiped and cleaned. This wiping can be carried out making use of a suitable cleaning means, such as a sponge, mop or the like.
Thus, when the scrubbing element 101 has reached the far end opening of the pipe section at the end of the rinsing step, the scrubbing element 101 may be detached from the water supply tube 106 and a mop 114 may then be connected to the latter instead. The water supply tube 106 is then retracted, while stopping the water supply, so as to pull the mop 114 along the wall of the pipe section A, to thereby wipe and clean the inner surface of the pipe section A. As shown in FIG. 3, the mop 114 is not secured to the water supply tube 106, but is secured instead to a wire rope 115 adapted to be pulled by a winch D. After completion of this wiping and cleaning step, the inner surface of the pipe has been substantially cleaned and no contaminants are left on the surface. The wiping and cleaning step is optional and may be dispensed with.
Where the wiping and cleaning step is carried out, the drying step is carried out with the wire rope 115 left in the pipe section A. To the contrary, when wiping and cleaning are not performed, a wire rope is connected to the scrubber body 101 which has been moved to the other end opening of the pipe section, so that the wire rope may extend through the latter.
In both cases, the drying step is performed with a wire rope left in and extending through the pipe section A.
Drying is performed by an apparatus E illustrated in FIG. 4.
The apparatus E comprises flexible hose 117 having at its intermediate section a nozzle body 116 for jetting high pressure water, and a water pressurizer C connected to the nozzle body 116 through the water supply pipe 106 for supplying the nozzle body 116 with highly pressurized water.
The water pressurizer C and the water supply pipe 106 used in the previous step (FIG. 2) may be used as the pressurizer and the pipe in the drying step.
As will be seen from FIG. 9, the nozzle body 116 for jetting highly pressurized water comprises suction pipe 120, which may be made of metal provided with outwardly diverging passage 118 and having ends of lesser and greater inner cross-section, as well as a nozzle tube 121 screwed to the suction pipe 120 having a diverging cross-section 119. At the central portion of the nozzle body 116, a restriction 122 is provided which is surrounded by annular passage 123. The annular passage 123 communicates with the passage 119 formed in the nozzle tube 121 through a plurality of jet nozzle ports 124 which are suitably circumferentially distributed.
The water supply pipe 106 leading from the water pressurizer C is detachably connected to a connecting passage 125 which in turn communicates with the annular passage 123.
The nozzle ports 124 are formed at an inclination to the axis of the passage 119 so that their extensions do not intersect at a point ahead of these nozzle ports (FIG. 10). Therefore, a rotary component of force is imparted to the water jetted from the nozzle ports 124 so as to increase the velocity of the water flowing in the passage 119, thereby obtaining a higher vacuum, i.e., sucking force at the suction pipe 120.
Flexible hoses 117' and 117 of suitable lengths are connected to the suction side end and the nozzle side end of the nozzle body 116 respectively.
As shown in FIG. 4, in use, hose 117' is connected to one end opening of the pipe section A in the bore B', while hose 117 is extended into a suitable water disposal line such as a gutter in the vicinity of the site. After connecting the water supply pipe 106, which may be the one which was used in the previous scrubbing step, to the connection pipe 125 of the nozzle body 116, highly pressurized water of about 250 Kg/cm 2 is fed into the annular passage 123 through the water supply pipe 106 and the connecting pipe 125.
The pressurized water forcibly fed to the annular passage is vigorously jetted from the passage 119 through the nozzle ports 125 such that a rotational component of force is imparted to the water thereby increasing its velocity. The jetted water is finally led to the end of the hose 117 and discharged therefrom. As the water flows through the passage 119 at a high velocity, a vacuum is generated in passages 118 and 119 of the nozzle body 116, so that air is violently induced through pipe section A (FIG. 4), flexible tube 117' and then through the suction pipe 120. Consequently, a flow of air is caused in the pipe section A, so as to fully evaporate the water and moisture adhering to the inner wall of the pipe section A.
The time required for the drying may be very substantially shortened by connecting the end of a hose 126 of an air heater G to the other end opening A' of the pipe section A, so as to feed hot air into the pipe section A as shown in FIG. 4. In this embodiment of the invention, it is not always necessary to connect the hose 126 of the air heater G to the pipe section A. Thus, a sufficient shortening of the drying time may be obtained simply by placing the end of the hose 126 in the bore B. Also it is to be noted that the use of the air heater G is not indispensable, and that drying can be completed in a reasonable period of time, by solely inducing ambient unheated air.
It is noteworthy that the time required for drying the inside of the pipe section is shortened by inducing air through the pipe section in the described manner. More specifically, by simultaneously feeding hot air to the bore B, by placing the end of the hose 126 of the air heater G in the bore B, and the induction of air by the operation of the apparatus E having the nozzle body 116, so as to forcibly induce the mixture of heated and unheated air through the pipe, the time required for completely drying the inside of the pipe which is usually about 2 hours can be shortened to about 10 to 15 minutes, when air having a temperature of about 20° C. to about 50° C. is used. In summer, when temperatures are warmer (about 30° C. or more) the air is already warm and supplemental heating is unnecessary.
As may be seen from FIG. 5, after drying, the inner surface of the pipe section is next coated with an anti-rust plastic paint from a source H, to prevent renewed generation and adherence of rust, scales and other contanimants. Painting is performed with a painting device and a mixer 36.
The anti-rust plastic paint may advantageously comprise a mixture of a main liquid which is an epoxy resin and a hardening liquid. The liquids are atomized, after having been mixed with each other, and applied to the inner surface of the pipe section by means of a painting apparatus which will now be described.
Although a wide variety of paints and hardening materials may be used, the preferred paint composition comprises, by weight, about 90.0% epoxy resin, 9.9% titanium oxide, and 0.1% silica. The preferred hardening material comprises, by weight, about 60.0% modified amine adduct, 27.9% calcium carbonate, 12.0% barium sulfate, and 0.1% carbon black.
As shown in FIG. 11 the painting apparatus H has a painting device K comprising an air motor 10 (FIG. 18); a paint supply device J adapted to supply the painting device K with the paint, a pressurized air supplying device C adapted to supply the painter K with pressurized air, and a towing device adapted to tow the painting device K. The painting device K comprises a casing 1 of a small length and a small diameter (FIGS. 18 and 19).
As may be seen from FIG. 20, a motor chamber 2 is formed at the center of the casing 1, so as to open in the front wall of the latter. The motor chamber 2 has an inlet and an outlet both of which are in communication with a passage 3 for pressurized air, which is formed to open into the rear wall of the casing 1.
A paint passage 4 is formed in the casing 1 to extend axially through the latter. The paint passage 4 is provided therein with a stirring element 5 which comprises a plurality of plate-like pieces arranged in series in a staggered manner such that the front edge of a piece lies at a predetermined angle to the rear edge of the adjacent piece (FIG. 17).
As seen from FIG. 14, a mixing case 36 is connected to the rear end of the casing 1, through a flexible wire 35, while a cover 6 is fastened to the front side of the casing 1 by means of screws 7 (FIG. 19).
FIG. 22 illustrates that the cover 6 has a bore 8 formed coaxially with the motor chamber to receive the rotary shaft, as well as a nozzle connection port 9 (FIG. 20) which is formed coaxially with the paint passage 4.
A mixing chamber 37 is formed in the mixing case 36. The mixing chamber 37 has an inlet port opening in the rear wall of the mixing case 36 and an outlet port opening in the front wall of the mixing case 36. Besides the mixing chamber, a passage 38 for pressurized air is formed to extend axially through the mixing case 36. The outlet port of the mixing chamber 37 is connected to the inlet port of the paint passage 4 of the casing 1, while the outlet port of the passage 38 for pressurized air is connected to the inlet port of the passage 3 for pressurized air of the casing 1, respectively, through flexible tubes 39 and 39'.
The mixing chamber 37 is formed to have a diameter much larger than those of the inlet and outlet ports. Stirring elements (not shown) similar to that disposed in the paint passage 4 of the casing 1 are provided in the inlet and outlet passages of the mixing chamber 37. A tridentate or "Y" coupling 70 (FIG. 15) is screwed at its one end into the inlet port of the mixing chamber 37 of the mixing case 36. The other two ends of the "Y" coupling 70 are connected to a main liquid supply pipe 48 and a hardening liquid supply pipe 49, respectively, of the paint supply device. At the same time, the inlet port of the passage 38 for pressurized air is connected to the end of a hose 60 of the pressurized air supplying device C (FIG. 11). These connections are made through respective joints M which are designed to allow disconnection in a simple manner.
More specifically, as shown in FIG. 16 the joints M comprise female members 71 and male members 72. The female members 71 of these joints are secured to the two end openings of the tridentate coupling or "Y" connector 70 which is screwed into the mixing case 36, as well as to the inlet port of the pressurized air passage 60 of the mixing case 38. The male members 72 of the joints M are secured to the main liquid supply pipe 48 and the hardening liquid supply pipe 49 of the paint supply device J, as well as to the air hose 60 of the pressurized air supply device C. The mixing case 36 is connected to the paint supply device J and to the pressurized air supply device C, by inserting the male members 72 into the corresponding female members 71.
Bores 73 are formed in the periphery of the female member 71, so as to receive rings 74. As the rings 74 are pressed by a press ring 75, they move radially inwardly to project from the inner peripheral wall of the female member 71, and become fitted in a groove 76 formed on the outer periphery of the male member 72, thereby securing the male and the female members to each other.
The press ring 75 has an annular shape, and is fitted around the female member 71 so that it is free to move in the axial direction relative to the latter. The press ring 75 is normally biased by means of a spring 77 to a position where it presses the rings 74 into the groove 76 of the male member 72. To disconnect the male and the female members (72, 71) from each other, the press ring 75 is simply displaced in the axial direction, against the force of the spring 77, so as to free the ring 74 from the groove 76.
Valves 79 and 80 are arranged in the female and male members 71 and 72 respectively. These valves are adapted to open when the female and male members 71 and 72 are coupled with each other, and to close when the members are disconnected from one another.
As illustrated in FIGS. 18 and 19 an air motor 10 housed in the motor chamber 2 of the casing 1 has a cylinder 12, a rotor 13, and blades 14. The air motor 10, when arranged in the motor chamber 2, divides the pressurized air passage 3 into a suction side section 3a and an exhaust side section 3b. The pressurized air introduced into the passage 3 is caused to flow through the cylinder casing 11 of the air motor 10 and ventilation ports 15, 15', 16, 16' of the cylinder 12, toward the outlet port, so as to be exhausted from the latter. The air flowing in the described manner collides with the blades 14, so as to impart a torque to the latter, thereby causing high speed rotation of the motor shaft 17 of the rotor.
Use of an air motor 10 as the driving means is preferred to use of complicated accessories and members such as electric wirings and is less troublesome to operate. Furthermore, the adoption of the air motor contributes, in combination with the separate arrangement of the mixing device from the casing, to minimizing the size of the painting device K. This effect of minimizing the size of the painting device K provides a remarkable advantage, because it affords smooth passage of the painting device even through the bent and curved portion of the pipe.
The motor shaft 17 extends into the bore 8 formed in the cover 6 of the casing 1. The air motor 10 is screwed to the cover 6 and to the bottom of the motor chamber, at portions 18 and 19, respectively. Therefore, the air motor 10 can be dismounted from the motor chamber 2, by removing the screws 7 and then unscrewing the air motor at portions 18 and 19.
Thus, when the motor is found to malfunction in any way during testing it may be easily and swiftly replaced with a spare motor. Consequently, the pipe renewal work is entirely free of problems relating to the time consuming repair and replacement of the motor, as well as failures attributable to trouble with the air motor in the course of renewing the pipe. This, of course, ensures faster renewal of the pipe as well as easier maintanence of the motor after the work.
FIGS. 18 and 19 further illustrate a cowling 20 having a peripheral wall and a bottom wall. A shaft-receiving bore 21 is formed at the center of the bottom wall and the cowling shaft 22 is inserted in this bore and fixed thereto. A number of small apertures 23 are uniformly distributed and formed in the peripheral wall of the cowling 20. The end of the cowling shaft is threaded at 24 and is engaged by two nuts 25 and 26 so as to cramp the bottom of the cowling 20 therebetween, thereby fixing the cowling shaft 22 to the cowling 20.
The cowling shaft 22 is connected at its rear end to the motor shaft 17 of the air motor 10. Both shafts 17 and 22 are provided with clutches 27 which engage with a grooved sleeve 27'.
Turning now to FIGS. 20 to 23, a bearing 28 is press-fitted to an intermediate portion of the cowling shaft 22, through which the latter is rotatably carried by a support sleeve 29 which also plays the role of a cover. A nut 26 located at the inside of the cowling 20 is received by a bore 30 in the support sleeve 29. The support sleeve 29 is screwed to the cover 6 at a portion 31 (FIG. 19). Therefore, the cowling shaft 22 can easily be taken apart by first removing the nut 25 and the washer 25', removing the cowling 20, and then unscrewing the support sleeve 29 from the cover 6.
This arrangement allows the simple removal of any paint which has penetrated the inside of the painting device during the operation of the latter and hardened onto the wall of the same, after the use of the device.
A spraying nozzle 32 comprises a closed small pipe having a plurality of nozzle orifices 33 in its wall, arranged in a row extending in the axial direction of the small pipe (FIG. 19). The spraying nozzle 32 is screwed at its base portion to a nozzle attaching bore 9 of the cover 6 of the casing, so that it extends into the cowling 20. The nozzle orifices 33 are preferably oriented so as to face in the general direction of rotation of the peripheral wall of the cowling 20, although they are spaced from the inner peripheral wall. By orienting the orifices 33 so that paint is thrown out in a direction which coincides with the rotation of the cowling, the paint is sprayed over the entire inner surface of the pipe.
As seen in FIG. 18, a support system 34 comprising at least three resilient legs is secured to the outer peripheral surfaces of the casing 1 and the mixing casing 36, evenly spaced along the circumference of the casing. Each resilient leg is secured at its rear end to the rear end portion of the casing 1, while the front end thereof extends obliquely outwardly toward the front side end of the casing 1. The angle of divergence of all the resilient legs is preferably equal.
In the above embodiment, the painting device K has a mixing device comprising a mixing case 36 having an inner mixing chamber 37 designed for a better mixing of the main liquid and the hardening liquid with each other. Instead of the above stated mixing device, it is also possible to use another type of mixing arrangement (not shown) comprising a flexible tube of a suitable length having stirring elements therein. In the latter case, one end of the flexible tube is connected to the inlet port of the paint passage of the casing, while the other end of the flexible tube is connected to the outlet of a tridentate coupling fed by two separate inlets. Needless to say, in this embodiment the wire rope for connecting the casing to the mixing device may be dispensed with, and the air hose of the pressurized air supplying device may be directly connected to the inlet port of the pressurized air passage of the casing.
Furthermore, the pressurized air passage 3 of the casing 1 or passage 38 of the mixing case 36 of the painting device K is preferably provided with a cleaning means 81 such as an air filter. Such a cleaning means is effective not only for removing fine dust and other contaminants suspended in the pressurized air so as to protect the air motor 10 from these dusts and contaminants, but also for preventing attachment of dust and contaminants, which are carried by the air exhausted from the air motor 10, onto the unpainted inner wall of the pipe section A, thereby eliminating a cause of early peeling of the paint.
In the embodiment illustrated in FIG. 14, the cleaning means 81 is located in the vicinity of the outlet port of the pressurized air passage 38 of the mising case. However, as was pointed out above, this is not the only possible location of the cleaning means 81, and the cleaning means 81 may instead be arranged in the pressurized air passage 3 of the casing 1, as well as at the suction side of the same.
The cleaning device provided at the exhaust side would be effective to take up the oil content which has been blown off from the air motor 10, thus ensuring secure adherance of the paint onto the inner surface of the pipe section A.
Reference is now made to FIGS. 11 to 13, showing the paint supply device C.
The paint used in the process of the invention is a bicomponent liquidus synthetic resinous paint comprising a main paint liquid and a hardening liquid which hardens when the two liquids are mixed with each other. The main liquid and the hardening liquid are reserved in separate liquid tanks 42 and 43, respectively. The liquid tanks 42 and 43 are provided with stirring means 46 and 46', respectively. In each case the stirring means comprise a stirring blade (only blade 45 is shown) adapted to be driven by a motor (44 for tank 42 and 44' for tank 43). The main liquid and the hardening liquid are sucked from respective liquid tanks 42 and 43 by airless pumps 47 and 47', respectively and fed to respective paint supplying pipes 48 and 49 which are flexible hoses connected at their one end to the liquid tanks 42 and 43 through the airless pumps 47 and 47' and at their other ends to the painting device K.
A rotary drum 50 is interposed at intermediate portions of the paint supplying pipes 48 and 49. More specifically, as shown in FIG. 13, the rotary drum 50 has a hollow shaft 51. From respective ends of the shaft 51, and extending through the latter are paint tubes 53 and 54. These paint tubes lead up to the peripheral surface of a drum body portion 52 (FIG. 12). At the same time, an air tube 55 is extended through one end of the shaft 51 and then through the latter, so as to lead up to the periphery of the drum body portion 52. The paint supply pipes 53' and 54' are connected to the paint tubes 53 and 54 which are wound around the drum body portion 52. The shaft 51 of the rotary drum 50 is rotatably supported by bearings, so that the rotary drum 50 can be freely rotated as the paint supply pipes 53' and 54' are pulled, to thereby optionally pay off the paint supply pipes 53' and 54'.
The above mentioned shaft 51 is associated with a shaft 57 which is adapted to be driven by a motor 56, so as to rotate in response to the rotation of the shaft 57. This arrangement constitutes towing means T for towing the painting device K. Rotation of the rotary drum 50 caused by actuation of the motor 56 occurs in a direction which retracts or rewinds the paint supply pipes 53' and 54'.
A clutch mechanism 58 interposed between the shaft 51 of the rotary drum 50 and the shaft 57 is adapted to disengage the shaft 51 from the shaft 57, when the rotary drum is rotated so as to pay off the wound supply pipes.
The pressurized air supply device C comprises an air compressor 59 and an air hose 60 connected to the compressor. The air hose 60' is wound around the rotary drum 50 along its intermediate portion, as is the case of the paint supply pipes 53' and 54'. Namely, the air tube 55 in the shaft 51 of the rotary drum 50 is interposed in the intermediate portion of the air hose 60. The paint supply device J, pressurized air supplying device C and the towing device T are all mounted on a vehicle 61 (FIG. 11), for easy transportation to and installation at the destined site.
In FIGS. 11 and 12, reference numerals 62 and 63 denote hoses for recirculating the main liquid and the hardening liquid for maintaining the flowing condition of these liquids even when they are not being supplied to the painting device K. As illustrated in FIG. 16, female members 71 are capable of engaging the male members 72 of joints M secured to the paint supply pipes 53' and 54'. Immediately after the completion of the painting, the painting device K is detached from the paint supply pipes 53' and 54', and the recirculation hoses 62 and 63 are connected to the paint supply pipes 53' and 54' instead.
Since the recirculation hoses 62,63 are connected to the liquid tanks 42,43, the main liquid and the hardening liquid are kept in the flowing condition.
The coating of the inner surface of a pipe section A is carried out by means of painting apparatus H in the following manner.
At first, the painting device K is connected to the end of the wire rope which has been previously passed through the pipe section A. As the wire rope is pulled, the painting device K is brought to the other end opening of the pipe section A. The painting device K is thus placed at the other end opening of the pipe section A, with its cowling 20 directed toward the opening. Then, the wire rope is disconnected from the painting device K.
Then, simultaneously with a supply of pressurized air from the pressurized air supplying device C, the main and hardening liquids are fed under pressure to the painting device K.
Consequently, the main and hardening liquids are mixed with each other and sprayed from the spray nozzle 32. At the same time, the air motor 10 which is energized by the pressurized air rotates the cowling 20 at high speed.
Paint sprayed from the spray nozzle is atomized through the small apertures 23 of the cowling. The centrifugal force caused by the high speed rotation of the cowling 20 scatters the paint onto the inner surface of the pipe section A. During this atomization of the paint, the painting device K is moved along the wall of the pipe section A, by means of the towing means T. As a result, the painting device K is gradually moved back to the end of the pipe section A through which it has been inserted into the pipe section A, by rewinding the paint supply pipes 53' and 54' as well as the air hose 60' by rotation of the rotary drum 50 in a direction which rewinds the pipes. The inner surface of the pipe section A is coated with the paint, in the course of the return movement of the painting device K. Thus, when the travel of the painting device K from one to the other end of the pipe section A has been completed, the entire inner surface of the pipe section A will be coated with anti-rust synthetic resinous paint.
As a result of the improved coating of the inner surface of the pipe which occurs during the painting step, the repeated generation of rust, scales and the attachment of other contaminants to the inner wall of the pipe section A is prevented for a longer period, thereby extending the life of the pipe which results in substantially less maintenance and a longer useful life. These results will be of great benefit to municipalities which are routinely faced with overhauling their existing piping systems.
After the coating has completely dried, the cut out pipe section A is suitably connected to the adjacent pipe section, and the bore B is refilled, to complete the renewal of the water service pipe in accordance with the method of the invention. The drying of the coating may be performed in the same way as that performed for drying the inner surface of the pipe after the rinsing step. It will be seen that, when the drying method described for the drying subsequent to the rinsing is applied to the drying of the coating, the drying time can conveniently be shortened by more than several hours.
Although the method and apparatus of the invention has been described with reference to particular scrubbers, scrapers, process materials and the like, it is to be understood that the scope of the invention should not be construed as being limited only to what has been specifically disclosed. Instead, the invention is limited only by the scope of the claims. | A method of cleaning and renewing sections of pipe is disclosed wherein the flow of fluid through the pipe is shut off and a scrubbing element is inserted into one end of the pipe. The scrubbing element is advanced through the pipe while at the same time ejecting a cleaning fluid to clean the inside of the pipe section. The inner surface of the section is then scraped to remove materials adhering to the inside of the section which were not previously removed. The removed materials are then flushed from the inside of the section and the section is dried. The inside of the section is then painted by passing a painting device through the section which applies a mixture of paint and hardening liquid to the inside of the pipe. A device is also disclosed for coating the inner surface of a pipe which comprises a casing, an air motor and a cowling operatively connected to the motor for scattering coating liquid fed to the device. The apparatus may further comprise a mixing device for mixing coating liquids prior to applying them to the inner surface of the pipe. | 45,679 |
BACKGROUND OF THE INVENTION
The present invention relates to the deposition of a thin film and specifically to semiconductor thin film processing.
Deposition is one of the basic fabrication processes of modern semiconductor device structures. Deposition techniques includes Physical Vapor Deposition (PVD, or sputtering), and Chemical Vapor Deposition (CVD) and numerous variations of CVD such as pulsed CVD, sequential CVD or Atomic Layer Deposition (ALD).
PVD process uses a high vacuum apparatus and generated plasma that sputters atoms or clusters of atoms toward the surface of the wafer substrates. PVD is a line of sight deposition process that is more difficult to achieve conform film deposition over complex topography such as deposition of a thin and uniform liner or barrier layer over the small trench or via of 0.13 μm or less, especially with high aspect ratio greater than 4:1.
CVD method is different from PVD method. In CVD, a gas or vapor mixture is flowed over the wafer surface at an elevated temperature. Reactions then take place at the hot surface where deposition takes place. The basic characteristic of CVD process is the reaction at the substrate of all the precursors vapors together. The reaction often requires the presence of an energy source such as thermal energy (in the form of resistive heated substrate, or radiative heating), or plasma energy (in the form of plasma excitation). Temperature of the wafer surface is an important factor in CVD deposition, because the deposition depends on the reaction of the precursors and affects the uniformity of deposition over the large wafer surface. CVD typically requires high temperature for deposition which may not be compatible with other processes in the semiconductor process. CVD at lower temperature tends to produce low quality films in term of uniformity and impurities. The reactions can be further promoted by plasma energy in plasma enhanced CVD process, or by photon energy in rapid thermal CVD process. CVD technology has been used in semiconductor processing for a long time, and its characteristics are well known with a variety of precursors available. However, CVD process needs major improvements to meet modern technology requirements of new materials and more stringent film qualities and properties.
Variations of CVD include pulse CVD or sequential CVD. In pulse or sequential CVD, the chemical vapors or the supplied energies such as plasma energy, thermal energy, laser energy are pulsed instead of continuous as in CVD process. The major advantages of pulse CVD is the high effects of the transient state resulted from the on-off status of the precursors or the energies, and the reduced amount of precursors or energies due to the pulsed mode. Reduced energy is desirable which can be accomplished in pulsed mode since it leads to less substrate damage such as the case of plasma processing for thin gate oxide. Reduced precursor is desirable which can be accomplished in pulsed mode for specific applications such as epitaxial deposition where the precursors need to react with the substrate in an arrangement to extend the single crystal nature of the substrate. There are no purging steps in pulsed CVD since cross contaminations or gas phase reactions are not a concern, and the purpose of the pulsing of the precursors or energies is to obtain the desired film characteristics.
Pulsed CVD can be used for create gradient deposition such as U.S. Pat. No. 5,102,694 of Taylor et al. Taylor discloses a pulsed deposition process in which the precursors are periodically reduced to create a gradient of composition in the deposited films. Taylor's pulsed CVD relies only on the changing of the first set of precursors to vary the film compositions.
Pulsed CVD can be used to modulate the precursors flow such as U.S. Pat. No. 5,242,530, titled “Pulsed gas plasma-enhanced chemical vapor deposition of silicon”, of Batey et al. Batey discloses a pulsed deposition process in which the precursor silane is modulated during a steady flow of plasma hydrogen. The pulsing of silane creates a sequence of deposition and without the silane pulses, the steady plasma hydrogen cleans and prepare the deposited surface.
Pulsed CVD can be used to pulse the plasma energy needed for the deposition process such as U.S. Pat. No. 5,344,792, titled “Pulsed plasma enhanced CVD of metal silicide conductive films such as TiSi 2 ”, of Sandhu et al. Sandhu discloses a pulsed deposition process in which the precursors are introduced into a process chamber, then the plasma energy is introduced in pulsed mode to optimize the deposition conditions. U.S. Pat. No. 5,985,375, titled “Method for pulsed plasma enhanced vapor deposition”, of Donohoe et al. discloses a similar pulsed CVD process with the plasma energy in pulsed mode but with a power-modulated energy waveform. The pulsing of the plasma energy allows the deposition of a metal film with desired characteristics. U.S. Pat. No. 6,200,651, titled “Method of chemical vapor deposition in a vacuum plasma processor responsive to a pulsed microwave source”, of Roche et al. discloses a pulsed CVD process with an electron cyclotron resonance plasma having repetitive pulsed microwave field to optimize the deposited films. U.S. Pat. No. 6,451,390, titled “Deposition of TEOS oxide using pulsed RF plasma”, of Goto et al. discloses a TEOS oxide deposition process using a pulsed RF plasma to control the deposition rate of silicon dioxide. The pulsing feature offers the optimization of the deposit films through the transient state instead of the steady state. Pulsing of plasma during nitridation process of gate oxide shows less damage than continuous plasma nitridation process because of higher interaction due to plasma transient state and less damage due to shorter plasma time.
Pulsed CVD can be used to pulse the precursors needed for the deposition process such as U.S. Pat. No. 6,306,211, titled “Method for growing semiconductor film and method for fabricating semiconductor devices”, of Takahashi et al. Takahashi discloses a pulsed CVD process to deposit epitaxial film of Si x Ge y C z . Epitaxial deposition requires a single crystal substrate, and the deposited film extends the single crystal nature of the substrate, different from CVD poly crystal or amorphous film deposition. To extend the single crystal nature of the substrate, the deposited precursors need to bond with the substrate at specific lattice sites, therefore a reduced precursor flow is highly desirable in epitaxial deposition to allow the precursors enough time to rearrange into the correct lattice sites. The process includes a continuous flow of hydrogen to dilute the precursors to be introduced. Then sequential pulses of silicon-based precursor, germanium-based precursor and carbon-based precursor are introduced to deposit an epitaxial film of Si x Ge y C z . To deposit epitaxial film, little amounts of precursors are needed, and this can be accomplished by short pulses (order of micro seconds) and further diluted in high flow of hydrogen. Takahashi discloses that the pulses of the precursors are not overlapped, but is silent on the separation of these pulses. The objective of Takahashi pulsed CVD is to deposit compound films, therefore the separation of these precursors is not relevant.
Pulsed CVD as described by Takahashi et al. to deposit epitaxial film of Si x Ge y C z , does not allow deposition of high coverage or conformal film on a non-flat substrate, such as in a via or trench for interconnects in semiconductor devices. The objective of Takahashi pulsed CVD is to deposit epitaxial films with sufficiently planar surface as observed by Takahashi et al., without mentioning of possible deposition on trenches or vias.
ALD is another variation of CVD using chemical vapor for deposition. In ALD, various vapors are injected into the chamber in alternating and separated sequences. For example, a first precursor vapor is delivered into the chamber to be adsorbed on the substrate, then the first vapor is turned off and evacuated from the chamber. Another precursor vapor is then delivered into the chamber to react with the adsorbed molecules on the substrate to form a desired film. Then this vapor is turned off and evacuated from the chamber. This sequence is repeated for many cycles until the deposited film reaches the desired thickness. There are numerous variations of ALD processes, but the ALD processes all share two common characteristics: sequentially precursor vapors flow and self-limiting thickness per cycle. The sequential precursor flow and evacuation characteristic offers the elimination of gas phase reaction commonly associated with CVD process. The self-limiting thickness per cycle characteristic offers the excellent surface coverage, because the total film thickness does not depend on precursor flow, nor on process time. The total film thickness depends only on the number of cycles. The ALD process then is not sensitive to the substrate temperature.
The maximum thickness per cycle of ALD process is one monolayer because of the self limiting feature that the substrate surface is saturated with the first precursor. The first precursor can adsorb on the substrate, or the first precursor can have some reaction at the substrate, but the first precursor also saturate the substrate surface and the surface is terminated with a first precursor ligand.
The throughput of ALD process depends on how fast a cycle is, and therefore a small chamber volume is critical. Furthermore, the fast switching of the precursor valves is desirable to allow a high throughput. A typical ALD cycle is a few seconds long, therefore the precursor pulses are in order of second. Precursor depletion effect can be severe for this short process time.
U.S. Pat. No. 5,916,365 to Sherman entitled “Sequential chemical vapor deposition” provides for sequential chemical vapor deposition (ALD) by a sequence of chamber evacuating, adsorption of the first precursor onto the substrate, then another chamber evacuation, then a second radical precursor to react with the adsorbed precursor on the substrate surface, and a third chamber evacuation. The Sherman process produces sub-monolayers per cycle due to adsorption. The process cycle can be repeated to grow the desired thickness of film. Sherman discloses an ALD process in which the first precursor process flow is self-limiting, meaning no matter how long the process is, the adsorption thickness cannot changed. U.S. Pat. No. 6,015,590 to Suntola et al., entitled “Method for growing thin films” discloses an ALD process which completely separates the precursors. Suntola process is an improved ALD process (called ALE by Suntola) meaning the deposition is achieved through the saturation of precursors on the substrate surface and the subsequent reaction with the reactants. The advantage of Suntola process is the complete separation of precursors, with a better than 99% purging between pulses of precursors to prevent cross reactions.
U.S. Pat. No. 6,200,893, and its divisions (U.S. Pat. No. 6,451,695, U.S. Pat. No. 6,475,910, U.S. patent publication 2001/0002280, U.S. patent publication 2002/0192954, U.S. patent publication 2002/0197864) to Sneh entitled “Radical-assisted sequential CVD” discusses a method for ALD deposition. Sneh sequence process is a variation of ALD process. Sneh discloses a deposition step for the first precursor introduction, but the deposition of Sneh is self limiting because of the surface saturation with ligands. In fact, in U.S. Pat. No. 6,475,910, Sneh discloses a method to extend the thickness of the first precursor introduction step. The disclosure discloses another ALD process to sequential precursor flows to increase the thickness of the first precursor introduction step. In a way, this is similar to a nested loop, where the thickness of the first precursor flow step of an ALD process can be increased by another ALD process.
SUMMARY OF THE INVENTION
The present invention provides a hybrid deposition process of CVD and ALD, called NanoLayer Deposition (NLD). A co-pending application “Nanolayer thick film processing system and method” of the same authors, Ser. No. 09/954,244, filed Sep. 10, 2001 and published Mar. 13, 2003, Pub. No. 20030049375 A1, has been disclosed and is hereby incorporated by reference.
In one aspect of the invention, the present invention method to deposit a thin film on a substrate comprises the steps of:
a. introducing a first plurality of precursors to deposit a thin film on a substrate, the deposition process being not self limiting;
b. purging the first precursors; and
c. introducing a second plurality of precursors to modify the deposited thin film, the second plurality of precursors having at least one precursor different from the first plurality of precursors.
The deposition step in the present invention is not self limiting and is a function of substrate temperature and process time. This first step is similar to a CVD process using a first set of precursors. Then the first set of precursors is turned off and purged and a second set of precursors is introduced. The purpose of the purging step is to avoid the possible interaction between the two sets of precursors. Therefore the purging can be accomplished by a pumping step to evacuate the existing precursors in the process chamber. The characteristic of the pumping step is the reduction in chamber pressure to evacuate all gases and vapors. The purging can also be accomplished by a replacement step by using a non reacting gas such as nitrogen or inert gas to push all the precursors out of the process chamber. The characteristic of the replacement step is the maintaining of chamber pressure, with the precursor turned off and the purge gas turned on. A combination of these two steps can be use in the purging step, such as a pumping step followed by a nitrogen or argon replacement step. The second set of precursors modifies the already deposited film characteristics. The second set of precursors can treat the deposited film such as a modification of film composition, a doping or a removal of impurities from the deposited film. The second set of precursors can also deposit another layer on the deposited film. The additional layer can react with the existing layer to form a compound layer, or can have minimum reaction to form a nanolaminate film. The deposition step is preferably a disordered film deposition, in contrast to an ordered film deposition as in an epitaxial film. Deposition conditions for disordered film deposition are much simpler to achieve with less initial surface preparation and less special considerations relating to the order of the deposited films. In ordered film deposition like epitaxial film deposition, small amount of precursors is typically used to allow the precursors the needed time to arrange themselves on the surface to form crystalline film. For that purpose, pulsed CVD is highly suited for epitaxial film deposition. The epitaxial deposition also requires a buffer layer to ensure a continuous lattice growth, especially with a dis-similar lattice structure of the substrate and the deposited film.
The present NLD method to deposit a film differs markedly from CVD method with a sequential process and with the introduction of the second set of precursors. The present NLD method differs from pulse or sequential CVD with a purging step and with the introduction of the second set of precursors. The introduction of the second set of precursors after purging the first precursors in a cyclic sequential process allows the modification of the deposited film in a manner not possible in CVD and pulse and sequential CVD methods.
The pulsed CVD processes employing the pulsing of precursors to modify the composition such as gradient of the deposited films differ from the present invention NLD process because of the lacking of the second set of precursors to modify the properties of the deposited films.
The pulsed CVD processes employing the pulsing of deposition precursors in the presence of plasma precursors to modify the deposited film characteristics such as a smoother surface differ from the present invention differs from the present invention NLD process because of the lack of the purging step between the pulses, and because the plasma precursors are present throughout the deposition time. This pulsed CVD process allows the mixture of the continuous plasma precursors and the deposition precursors. Instead, the NLD process offers a purging step between the two sets of precursors to avoid cross contamination, to avoid possible gas phase reaction and to prepare the process chamber for different processes. For example, the purging step clear out the precursor such as an MOCVD precursor before turning on the plasma because the plasma is difficult to strike with the presence of a vapor.
The pulsed CVD processes employing the pulsing of plasma energy to modify the deposited film characteristics such as smoother film, different deposition rate, less damage to the deposited films differ from the present invention NLD process because of the lacking of the second set of precursors to modify the properties of the deposited films and the lacking of the purging step between the pulses. The pulsing feature offers the optimization of the deposit films through the transient state instead of the steady state, and therefore differ significantly with the present invention NLD method of using the second set of precursors to modify the deposited film characteristics.
The pulsed CVD processes employing the pulsing of deposition precursors to form epitaxial film differ from the present invention NLD process because of the lacking of the purging step between the precursors pulses. The purging step allows the use of incompatible precursors due to the separation effect of the purging step. The difference between pulsed CVD and NLD also includes the conceptual purpose of the two methods. The objective of pulsed CVD is to employ a suitable set of precursors and conditions to deposit the desired films, while the objective of NLD is to deposit a film, even an undesired film, and to provide a modification and treatment step to convert the undesired film into a desired film. Instead of finding a way to deposit a film with all the desired characteristics as in CVD or pulsed CVD, NLD finds a way to treat or modify an existing film to achieve a film with the desired characteristics. Further, recognizing that treating and modifying an existing is difficult when the thickness is large, NLD offers a cyclic process of depositing and treating or modifying, so that the treatment process is performed on very thin film and to achieve a thicker film.
The present NLD method to deposit a film also differs markedly from ALD method with a non self-limiting deposition step. The deposition step in the present invention NLD method is a function of substrate temperature and process time. The deposition/adsorption step in ALD method is a self-limiting step based on the saturation of precursor ligands on the substrate surface. Once the surface is saturated, the deposition/adsorption in ALD method stops and any excess precursor vapors have no further effect on the saturated surface. In other words, the deposition/adsorption step of ALD method is independent of time after reaching saturation. The ALD method also has less dependent on substrate temperature than CVD or NLD methods. Therefore the present invention NLD method has many distinct differences from ALD method.
In other aspect of the invention, the method of deposition further comprises a last purging step after step c. Similar the previous purging step, the last purging step is to remove the second set of precursors from the process chamber, either by evacuation, by replacement, or any combinations. In many applications, the treatment step can only treat a thin film, or the treatment step is much more effective if treating only a thin film, therefore the present invention further comprises a further step of repeating the previous steps until a desired thickness is reached. The last purging step can be optional because its purpose is to prevent possible reaction between the two sets of precursors. In cases that there are minimal reactions between these two sets of precursors, the last purging step can be eliminated to have a shorter process time and higher throughput.
The present invention also provides for the extension to a plurality of other sets of precursors. Another third set of precursors would enhanced the modification of the deposited film at the expense of process complexity and lower throughput. Another two sets of precursors would create a multilayer thin film or a nanolaminate film.
The present invention NLD process can be performed in any process chamber such as a standard CVD process chamber or an ALD small volume, fast switching valve process chamber. The chamber wall can be cold wall, or warm wall, or hot wall depending on the desired outputs. The delivery system can be showerhead delivery to provide uniform flow, or a sidewall inlet to provide laminar flow, or a shower ring to offer circular delivery. The precursor delivery can be liquid injection where the liquid precursors are delivered to a heated vaporizer to convert the precursors into vapor form before delivering into the process chamber. The precursor delivery can be vapor draw where the vapor of a liquid precursor is drawn from the liquid precursor container. The precursor delivery can be bubbler where the vapor of the liquid precursor is enhanced with the bubbling feature of a non reactive carrier gas.
The steps in the present invention can be any CVD deposition step such as thermal activated CVD, plasma enhanced CVD using parallel plate plasma, or inductive coupled plasma (ICP), or microwave plasma, or remote plasma, or rapid thermal processing using lamp heating. Not only the deposition step can be a deposition step, the treatment step can also be a CVD deposition step to modify the deposited film properties.
The treatment step can be a plasma treatment, or a temperature treatment. The plasma treatment can be an energetic species, and can be further enhanced with a bias to give kinetic energy to the energetic species. A strong bias can create reaction such as an ion implantation as in immersion ion implantation technology. In general, a highly energetic species in the treatment step can help in modification the deposited film properties. A bombardment of species can be employed to improve the roughness of the deposited film. A chemical reaction can be employed to remove impurities or to change film compositions and to modify the physical properties such as film density.
The present invention method can use any CVD precursors or MOCVD precursors. The deposition step is further enhanced with the second set of precursors to allow film properties that are difficult or impossible with CVD method. The precursors can be thermal activated, plasma activated or RTP activated. The precursors can be hydrogen, nitrogen, oxygen, ozone, inert gas, water, or inorganic precursors such as NH 3 , SiH 4 , NF 3 , or metal precursors such as TiCl 4 , or organic precursors, or metal organic precursors such as TDMAT, TDEAT, TMEAT, PDMAT, PDEAT.
In general, the process temperature of the present invention is lower than the temperature of similar CVD process to obtain the lower deposition rate and better uniformity. A typical process temperature is between 100° C. to 1000° C., depending on the thermal budget of the overall process. Metal interconnect of a semiconductor process requires the process temperature to be less than 500° C., and the new low dielectric constant (low k) interlevel dielectric process requires the process temperature to be less than 400° C., or even 350° C. For device fabrication, the temperature can be higher, up to 600° C. or even 800° C.
The process time of the present invention of each step is between the range of msec to many minutes. Shorter process time is desirable, but too short a process time can create many reliability issues such as timing requirements, component requirements. A typical throughput of 10 to 60 wafers per hour is acceptable for semiconductor fabrication. Using about 4 to 20 cycles per film thickness, that translates to about 3 to 90 seconds per step.
One aspect of the present invention is the plasma energy. To treat the sidewall surface of a high aspect ratio trench, the plasma is a high density and high pressure plasma. High density plasma can be accomplished with ICP or microwave. High density plasma can also be accomplished with remote plasma.
High pressure plasma can be a little harder. High density and high pressure plasma require a high energy in the chamber volume to compensate for the high collision loss due to the presence of many charged and neutral particles. To increase the power delivered to the chamber volume, an ICP power source needs to be close to the chamber volume and contains many inductive segments. These two requirements are difficult to fulfill because as the number of inductive segments increase, they are farther away from the chamber volume due to the size of the inductive segments. The inductive segments are typically a coil for the plasma source and carry a large current, therefore need to be water cooled. Conventional inductive coil has cross section of a square or a circle with a hollow center for water cool flow. The increase of number of inductive coil turns will increase the power, but since the successive turns are farther away from the chamber, the power increase is somewhat reduced, and at a certain distance, the power increase is no longer significant. Our plasma inductive coils is an innovation design and has a ribbon-like cross section with the width is many times larger than the thickness. A co-pending application “Plasma semiconductor processing system and method” of the same authors, Ser. No. 09/898,439, filing date Jul. 5, 2001 has been disclosed. With the thickness of the helical ribbon inductive coil is much less, order of mm as compared to 5 or 10 mm as conventional inductive coil, the inductive coils are much closer to the chamber volume and therefore can deliver a high power to the process chamber, resulting in a high density, high pressure plasma for sidewall structure treatments. The heat removal issue of the helical ribbon is much more significant than the conventional inductive coils, but it is an engineering issue and can be solved. With this new source of plasma, our process chamber pressure can be as high as 1000 milliTorr, and with further improvement, can reach 5 Torr, as compared to the typical process pressure of 10 to 100 milliTorr. As a result, the sidewall treatment of our process can be very good and the result is close to 100% conformality at the sidewall and the top and bottom surface.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a flowchart of a prior art CVD process.
FIG. 2 is a flowchart of a prior art pulse CVD process.
FIG. 3 is a flowchart of a prior art ALD process.
FIG. 4 is a flowchart of the present invention NLD process.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a flowchart of a prior art CVD process. In step 10 , the precursors are introduced into the process chamber. The precursors are then react at the substrate surface to form a deposited film in step 11 . The conditions for the precursors reaction can include plasma energy, thermal energy, photon energy, laser energy. The deposition characteristics of CVD process is the non self-limiting nature, meaning increase with process time and substrate temperature.
FIG. 2 shows a flowchart of a prior art pulse CVD process. In step 20 , the precursors are introduced into the process chamber in pulses. The precursors are then react at the substrate surface to form a deposited film in step 21 . Similar to CVD process, pulse CVD process can incorporate plasma energy, thermal energy, photon energy, laser energy. The pulse CVD process conditions can include precursor pulsing, plasma pulsing, thermal energy pulsing, photon energy pulsing, and laser energy pulsing. The deposition characteristics of pulse CVD process is the repeated CVD deposition process.
FIG. 3 shows a flowchart of a prior art ALD process. In step 30 , the precursors are introduced into the process chamber. Then the precursors are purged from the process chamber in step 31 . Another set of precursors is introduced into the process chamber in step 32 . Then this set of precursors is purged from the process chamber in step 33 . This purging step 33 is optional. The sequence can be repeated in step 34 until a desired thickness is reached. The basic characteristics of ALD process is the saturation of precursors in step 31 , meaning the deposition or adsorption of precursors in this step is self limiting, and is sensitive to process time and substrate temperature. The two sets of precursors are react in step 32 after the introduction of the second set of precursors. The purging step 31 is required to separate the two sets of precursors to prevent gas phase reaction and to preserve the surface reaction of ALD process.
FIG. 4 shows a flowchart of the present invention NLD process. In step 40 , the precursors are introduced into the process chamber. Then the precursors are purged from the process chamber in step 41 . Another set of precursors is introduced into the process chamber in step 42 . Then this set of precursors is purged from the process chamber in step 43 . This purging step 43 is optional. The sequence can be repeated in step 44 until a desired thickness is reached. The basic characteristics of NLD process is the non self limiting nature of the deposition in step 41 , meaning the deposition of precursors in this step is dependent on process time and substrate temperature. The two sets of precursors are not react with each other in step 42 . Instead, the second set of precursors react with the products of the first set of precursors, resulting after step 40 . The purging step 41 is normally needed to separate the two sets of precursors to prevent gas phase reaction, but may not be required in all cases because NLD process does not depend on the two sets of precursors interacting.
The present NLD method to deposit a film differs significantly from CVD method with a sequential process and with the introduction of the second set of precursors. The present NLD method differs from pulse or sequential CVD with a purging step and with the introduction of the second set of precursors. The cyclic sequential deposition using two sets of precursors with a purging step separating these two sets of precursors allows the modification of the deposited film in a manner not possible in CVD and pulse and sequential CVD methods. The following examples discuss the advantages of NLD versus CVD. In saying CVD, it also includes pulse CVD or sequential CVD methods.
An example is the surface coverage property of a deposited film. A typical CVD process would run at high temperature and continuously until a film is deposited. The uniformity and surface coverage of the CVD process would depend solely on the reaction mechanism of the chemical precursors and the initial substrate surface. In contrast the present invention NLD method provides a second set of precursors to modify the substrate surface characteristics during the deposition time, effectively allowing a substrate surface similar to the initial surface all the time to prevent surface property changes during the deposition process. NLD method offers an extra controllability to modify the substrate surface during deposition time to improve the surface coverage property of the deposited film. An NLD silicon dioxide deposition using TEOS and oxygen as the first set of precursors and plasma argon or hydrogen or nitrogen as the second set of precursors offers more uniformity and surface coverage at a thin film than CVD process using TEOS/oxygen alone. Similarly, an NLD silicon nitride deposition process using silane/ammonia as a first precursors and plasma argon or hydrogen or nitrogen as the second set of precursors offers more uniformity and surface coverage at a thin film than CVD process using silane/ammonia alone.
Another example is the process temperature of a deposited film. The CVD process temperature is determined by the reaction mechanism to provide an acceptable quality film. Lower the process temperature in CVD process could change the deposited film properties such as impurity incorporation due to incomplete reaction, different stoichiometry of the film components. In contrast, the present invention NLD method can run at a lower temperature than CVD method and still offers acceptable quality film due to the ability to modify the deposited film at low temperature to obtain the desired film properties. This is also a distinction of the NLD method from the CVD method where the substrate temperature of the NLD method is lower than the CVD method for the same set of first precursors. Since the deposition step in both NLD and CVD depends on the substrate temperature, a lower substrate temperature would offer a lower deposition rate, and a better controllability of the deposited film such as surface coverage.
Another example is the densification of a deposited film. CVD method would deposit a complete film, then subject the whole film to a treatment such as annealing. Since the whole film is thick, the annealing would take a long time, and in some cases, certain limitation of diffusion could prevent the heat treatment to reach the bottom of the deposited film. In contrast, the present invention NLD method offers the cyclic sequential method of depositing and heat treatment of a small fraction of the whole film. The whole film will be deposited a number of time, each time with only a fraction of the thickness. Since the fraction of the thickness is much thinner than the whole film thickness, the heat treatment would be short and effective. The number of cycles can chosen to optimize the film quality or the short process time.
Another example is the capability of composition modification of the deposited film such as the carbon removal treatment of a carbon-containing deposited film. CVD method would deposit a complete film containing a certain amount of carbon, then subject the whole film to an energetic species such as plasma hydrogen to react with the carbon to remove the carbon from the deposited film. To reach a thick film, the energy needed for the energetic species would be very high, in many cases impractical and potentially cause damage to the deposited film or the underlying substrate. In contrast, the present invention NLD method offers the cyclic sequential method of depositing and carbon removal treatment of a small fraction of the whole film. Since the film to be treated is much thinner, and can be chosen as thin as one desires, the energy of the energetic species can be low and within the range of practicality, to remove the carbon and not damage the deposited film or the underlying substrate.
Another example is the avoidance of gas phase reaction such as the deposition of TiN using TDMAT (tetra dimethyl amine titanium) metal organic precursor with NH 3 . CVD method would impractical since TDMAT would react with NH 3 in gas phase to create particles and roughen the deposited film. A CVD deposition of the whole film using TDMAT and then subjected the deposited film with NH 3 would not be possible to treat the whole film thickness. In contrast, the present invention NLD method offers the cyclic sequential method of depositing using TDMAT and NH 3 treatment of a small fraction of the whole film. With a deposited film thickness of TDMAT of less than a few nanometer (1-2 nm), the treatment of NH 3 would be effective, and only the cyclic sequential method of NLD would be able to provide. Similarly results can be obtained from TDEAT, TMEAT for titanium organic metal precursors, PDMAT, PDEAT for tantalum organic metal precursors, other organic metal precursors such as copper hfac tmvs, inorganic precursors such as copper hfac (I), copper hfac (II), copper iodine, copper chloride, titanium chloride together with plasma treatment of N 2 , H 2 , Ar, He, or NH 3 .
Another example is the modification of the property of the deposited film such as the deposition of a oxygen-rich film, a nitrogen-rich film, an oxy-nitride film, or a metal-rich film. To vary the content of any component in a deposited film such as oxygen, CVD method would require the adjustment of all the precursor components. This is not an easy task since the incorporation of a element is not directly proportional to its presence in the precursor vapor form. Many times it is not even possible to modify the resulting film components since CVD is a product of a chemical reaction, and any excess precursors would not participate in the reaction. In contrast, the present invention NLD method offers the cyclic sequential method of depositing and treatment of a small fraction of the whole film. The treatment step is a separate step and can be designed to achieve the desired results. If an oxygen-rich film is desired, a energetic oxygen treatment step such as a plasma oxygen, or an ozone flow, could incorporate more oxygen into the deposited film. The incorporation can be done if the deposited film is thin enough, a condition only available in the present invention NLD method, not CVD. If an nitrogen-rich film is desired, a energetic nitrogen treatment step such as a plasma nitrogen, or an ammonia (NH 3 ) flow, could incorporate more nitrogen into the deposited film. If an oxy-nitride film is desired, a energetic oxygen treatment step could incorporate more oxygen into the deposited film of nitride, or a energetic nitrogen treatment step could incorporate more nitrogen into the deposited film of oxide.
Another example is the incorporation of impurity to modify the deposited film property such as copper doped aluminum film, carbon doped silicon dioxide film, fluorine doped silicon dioxide film. For example, the electromigration resistance of pure aluminum is poor, and this resistance is much improved with the incorporation of a small amount of copper, typically of less than a few percents. CVD method would have to invent compatible precursors of aluminum and copper that can deposit a desired mixture. In contrast, the present invention NLD method offers the cyclic sequential method of depositing a fraction of the aluminum film and incorporate copper into the film fraction during the treatment sequence. Since the deposition uses the aluminum precursors and the treatment uses the copper precursors, and these precursors are separately and sequentially introduced into the process chamber, compatibility is not a big issue.
Another example is the deposition of multilayer films or nanolaminate films. Nanolaminate films are multilayer films but the different layers can be very thin, sometimes not complete layers, and sometimes even less than a monolayer. A CVD method would be impractical as it requires multiple process chamber and the capability of moving between these chambers without incurring contamination and impurities. In contrast, the present invention NLD method offers the cyclic sequential method of depositing a first layer film, and then deposit a second layer film during the treatment sequence. The first layer could be as thin as one desired, such as a fraction of a monolayer, or as thick as one desired, such as a few nanometer.
The present NLD method to deposit a film also differs significantly from ALD method with a non self-limiting deposition step. The deposition step in the present invention NLD method is a function of substrate temperature and process time. The deposition/adsorption step in ALD method is a self-limiting step based on the saturation of precursor ligands on the substrate surface. Once the surface is saturated, the deposition/adsorption in ALD method stops and any excess precursor vapors have no further effect on the saturated surface. In other words, the deposition/adsorption step of ALD method is independent of time after reaching saturation. The ALD method also has less dependent on substrate temperature than CVD or NLD methods. Therefore the present invention NLD method has many distinct differences from ALD method.
One example is the non self-limiting feature of the present invention NLD method allows the NLD method to share the precursors of CVD method, in contrast to the inability of ALD method to use CVD precursors. The deposition step of the present invention NLD method is similar to the deposition step of the CVD method, with the possible exception of lower temperature, therefore the NLD method can use all the precursors of the CVD methods, including the newly developed metal organic precursors or organic metal precursors (MOCVD precursors). In contrast, the precursor requirements of ALD are different because of the different deposition mechanisms. ALD precursors must have a self-limiting effect so that the precursor is adsorbed on the substrate, up to a monolayer. Because of this self limiting effect, only one monolayer or a sub-monolayer is deposited per cycle, and additional precursor will not be deposited on the grown layer even when excess precursor or additional time is supplied. The precursor designed for ALD must readily adsorb at bonding site on the deposited surface in a self-limiting mode. Once adsorbed, the precursor must react with the reactant to form the desired film. These requirements are different from CVD, where the precursors arrive at the substrate together and the film is deposited continuously from the reaction of the precursors at the substrate surface. Thus many useful CVD precursors are not viable as ALD precursors and vice versa. And it is not trivial or obvious to select a precursor for the ALD method.
Another example is the ease of incorporation of the enhancement of CVD technology such as plasma technology, rapid thermal processing technology. By sharing precursors with CVD, the NLD method also can share all the advancement of CVD without much modification. A plasma deposition step in NLD can be designed and tested quickly because of the available knowledge in CVD method.
Another example is the substrate surface preparation. This is a consequence of the different deposition mechanism of NLD and ALD. In ALD, the substrate and substrate preparation are very critical and are a part of the deposition process since different surfaces and surface preparations will lead to different film quality and properties. In contrast, in NLD, similar deposition process occurs with different surface preparations or different surfaces because the basic mechanism is the deposition step, depending only on precursors reaction and the energy supplied, and depending little on the substrate surface. The only dependence of NLD on the substrate surfaces is the nucleation time, since different surfaces have different time for the precursors to nucleate and start depositing. This characteristic is observed in our laboratory when we deposit TiN using NLD process on different substrates, a silicon dioxide substrate, an organic polymer substrate, and a porous dielectric substrate. The TiN films on these 3 different substrates have similar film quality and properties, with only different in thickness, due to the difference in nucleation times on different surfaces. Deposition of epitaxial films also requires intensive preparation of the substrate so that the first layer of atoms deposited would grow epitaxially or in an ordered arrangement from the substrate crystal. NLD process of non-epitaxial film allows conformal deposition or highly uniform coverage of a thin film over the vias and trenches, and especially high aspect ratio structures in semiconductor devices.
Another example is the ability to use MOCVD precursors. The MOCVD precursors contain a significant amount of carbon due to its organic content. The present invention NLD process uses MOCVD precursors with ease due to the deposition step using MOCVD precursors and the treatment step to remove any carbon left behind during the deposition step. An effective carbon removal step is the introduction of energetic hydrogen or nitrogen such as plasma hydrogen or nitrogen. In contrast, the use of MOCVD precursors in ALD method would demand significant research, and so far to the best of our knowledge, there is no commercially successful ALD process available using MOCVD precursors.
Another example is the non self-limiting feature of the present invention NLD method also allows the NLD method to adjust the thickness of the deposition step, or the treatment step, or both, to achieve a higher thickness per cycle. The ALD method is based on the saturation of ligands on the substrate surface, therefore the thickness per cycle is fixed and cannot be changed. In contrast, the thickness per cycle in the present invention NLD method is a function of process temperature and process time. The optimum thickness for NLD process is the largest thickness per cycle and still able to be treated during the treatment step. An NLD process deposits TiN using TDMAT precursor and plasma nitrogen treatment can have the thickness per cycle any where from sub nanometer to a few nanometers. The ability to vary the thickness per cycle allows the NLD process to use less cycles for the same total film thickness, leading to a faster process time and offering higher throughput than ALD process.
Another example is the non self-limiting feature of the present invention NLD method also allows the NLD method to vary the individual thickness of the resulting film, such as a few thicker or thinner layers in the middle of the deposited film, a manner not possible in ALD method. Some applications require a thick film where the film quality is only critical to the interface, the center portion of the film can be deposited with a very high thickness per cycle to increase the throughput while the beginning and the end of the deposition use a much thinner thickness per cycle to satisfy the requirement of a high quality interfaces. This feature is not possible with ALD process where all the cycles having the same thickness per cycle.
Another example is the process temperature of a deposited film. The ALD process temperature is largely fixed by the chemical reactions between the ligands of the precursors, and therefore ALD method is insensitive to the substrate temperature. In contrast, the present invention NLD method can run at a slightly higher temperature than ALD to offers the deposition characteristics, meaning a process dependent on process temperature and time. Furthermore, the NLD process can run at a much higher temperature to provide a larger thickness per cycle. The variation in thickness per cycle of NLD process can be accomplished by changing the substrate temperature, where a higher temperature would result in a high deposition rate, leading to a larger thickness per cycle. The change in substrate temperature is probably best accomplished by rapid thermal processing using radiative heat transfer for fast response time. A resistive heated substrate could provide the baseline temperature, and a lamp heating would provide the increase in temperature needed for larger thickness per cycle.
Another example is that it is not essential to have a purging step between the deposition and the treatment in the present invention NLD method because it is possible that the precursors in both steps are compatible. In contrast, ALD method requires the purging step between these two steps because of the designed reaction at the substrate surface. The purging step in NLD method helps overall in the cyclic sequential deposition scheme where the incompatibility of the two sets of precursors could cause potential damage. In rare cases where the two sets of precursors are compatible, the purging step is not critical and can be reduced or eliminated to improve the throughput.
Another example is the controllability of surface coverage. ALD method has excellent conformality and surface coverage, meaning this method will provide a theoretically perfect coverage of any configuration, as long as there is a pathway to it. But ALD is not capable of turning off this feature, meaning the excellent surface coverage is a characteristics of the ALD method. In contrast, in the present invention NLD, the surface coverage characteristics can be modified. In general, because of the deposition step in NLD is based on CVD, the thinner the thickness per cycle in NLD is, the better the surface coverage is. This degree of control offers NLD an unexpected advantage in porous substrate. ALD deposition on an open-pored porous substrate will travel through all the pores and deposit everywhere, potentially shorting the circuit if the deposited film is conductive. In contrast, NLD method can deliver a very high deposition rate at the beginning of the deposition cycle, effectively sealing off the open pores before starting deposition of a high quality thin film. By turning off the surface coverage feature, the degree of penetration of NLD into the porous material is significantly less than ALD method. Using this scheme, we have demonstrated a less penetration of the deposited film into the porous substrate. With further optimization, we believe that no penetration might be possible.
Another example is the flexibility of chamber design. The throughput of ALD is determined by the cycle time due to the independent of the thickness per cycle feature of ALD method. Therefore the chamber design in ALD is highly critical to achieve an acceptable throughput. ALD throughput depends strongly on many issues of chamber design, such as small chamber volume to ensure fast saturation and fast removal of precursors, fast switching valves to ensure quick response time of precursor on-off, uniform precursor delivery to ensure non-depletion effect of precursor. The fast response time requirement of ALD also puts a constraint on the timing requirement such as the synchronization of the precursor flow, the purging steps. In contrast, in the present invention NLD method, the chamber design issues are not any where as critical because of the potential higher thickness per cycle feature, leading to less number of cycles and higher throughput. Therefore a conventional CVD chamber with large volume, slow valve response time is adequate to perform NLD process. The NLD process could benefit from the chamber design of ALD, but NLD has the flexibility of trading some of the throughput for the simplicity of chamber design because the throughput of NLD without any chamber design consideration could be adequate for many applications. The advantage of the flexibility in chamber design is the ease of incorporate high density plasma into NLD process. High density plasma design requires a large chamber volume to equalize the energy of the charged and neutral particles due to high collision, and this requirement constraint contradicts with the small chamber volume requirement of ALD process, but acceptable with NLD process. | A hybrid deposition process of CVD and ALD, called NanoLayer Deposition (NLD) is provided. The nanolayer deposition process is a cyclic sequential deposition process, comprising the first step of introducing a first plurality of precursors to deposit a thin film with the deposition process not self limiting, then a second step of purging the first set of precursors and a third step of introducing a second plurality of precursors to modify the deposited thin film. The deposition step in the NLD process using the first set of precursors is not self limiting and is a function of substrate temperature and process time. The second set of precursors modifies the already deposited film characteristics. The second set of precursors can treat the deposited film such as a modification of film composition, a doping or a removal of impurities from the deposited film. The second set of precursors can also deposit another layer on the deposited film. The additional layer can react with the existing layer to form a compound layer, or can have minimum reaction to form a nanolaminate film. | 51,916 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a bonding structure between electronic device packages. More particularly, the present invention relates to a bump structure that can provide good bonding properties.
2. Description of the Related Art
In the fabrication of high-density electronic packages, a means of enhancing the bonding effect between an integrated circuit device and a carrier substrate, thereby increasing the production yield, is always an important research topic.
Using liquid crystal display (LCD) as an example, the technique for packaging an LCD has changed from chip-on-board (COB) to tape-automated-bonding (TAB) and then to the current fine pitch chip-on-glass (COG) due to the need for higher image resolution and the demand for a lighter and slimmer electronic product.
However, in most conventional packaging process that uses bumps as a means of bonding, the difference in the coefficient of thermal expansion (CTE) between the chip and the carrier substrate is quite significant. Therefore, after the chip and the carrier substrate are bonded together, warpage often occurs due to CTE mismatch between the chip, the bumps and the carrier substrate. As a result, the bumps are thermally stressed. Moreover, with the ever-increasing level of integration of the integrated circuit, the effects resulting from the thermal stress and the warpage are increasingly significant. One of the major effects includes a drop in the reliability of connection between the chip and the carrier substrate and the subsequent failure to comply with the reliability test.
K. Hatada in U.S. Pat. No. 4,749,120 proposed using gold bumps to serve as an electrical connection between a chip and a substrate, and in the meantime, using resin as a bonding agent between the two. However, the Young's modulus of metal is substantially higher than resin. Hence, in the process of joining the chip and the carrier substrate together and curing the resin, considerable contact stress must be applied. In addition, the gold bumps will be subjected to considerable peeling stress after the bonding process so that the gold bumps may peel off from the chip or the carrier substrate.
In another method, Y. Tagusa et. al in U.S. Pat. No. 4,963,002 proposed using nickel-plated (nickel) beads or silver particles to achieve electrical connection. Yet, this method is only suitable for bonding a small area. Furthermore, if the silver particles are used in the bonding process, the large Young's modulus of silver may lead to the same bump-peeling problem.
In yet another method, Sokolovsky et. al in U.S. Pat. No. 4,916,523 proposed using a unidirectional conductive bonding agent to bond the chip and the carrier substrate together. On the other hand, Brady et. al in U.S. Pat. No. 5,134,460 also proposed a design that involves coating a metallic layer over conductive metal bumps.
SUMMARY OF THE INVENTION
Accordingly, at least one objective of the present invention is to provide a method of minimizing the thermal stress problem in an electronic package due to a coefficient of thermal expansion (CTE) mismatch.
At least another objective of the present invention is to provide a method of resolving bump bonding problem due to Young's modulus problem so that the production yield is increased.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a composite bump suitable for disposing on the pad of a substrate. The composite bump includes a compliant body and an outer conductive layer. The coefficient of thermal expansion (CTE) of the compliant body is between 5 ppm/° C. and 200 ppm/° C. The outer conductive layer covers the compliant body and is electrically connected to the pad.
In one embodiment of the present invention, the Young's modulus of the compliant body is between 0.1 GPA to 2.8 Gpa, or between 3.5 Gpa to 20 Gpa, for example.
In one embodiment of the present invention, the compliant body is fabricated using polymer material. For example, the compliant body can be fabricated using polyimide or epoxy-based polymer.
In one embodiment of the present invention, the composite bump may further include a solder layer disposed on the outer conductive layer, for example. The solder layer is fabricated using lead-tin alloy, for example.
In one embodiment of the present invention, the compliant body can have the shape of a block and is disposed on the pad. The surface of the compliant body away from the pad can be a flat surface, a roughened surface or a curve surface.
In one embodiment of the present invention, the compliant body may include a plurality of protruding objects, for example. All the protruding objects can be disposed on the pad or on the peripheral region of the pad. However, a portion of the protruding objects may be disposed on the pad while the remaining protruding objects may be disposed on the peripheral region of the pad.
In one embodiment of the present invention, the compliant body may further include a substrate conductive layer disposed between the compliant body and the substrate. Furthermore, the outer conductive layer is connected to the substrate conductive layer. The compliant body has a block shape and extends to an area outside the pad. In addition, the surface of the compliant body away from the pad can be a flat surface, a roughened surface or a curve surface and the substrate conductive layer can be fabricated using a metal, for example.
Accordingly, the compliant body inside the composite bump in the present invention can provide a buffering effect during the bonding process. Furthermore, the coefficient of thermal expansion (CTE) of the compliant body can be adjusted to match the Young's modulus through design. As a result, the thermal stress is reduced and bonding effect is enhanced.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,
FIGS. 1A and 1B are schematic cross-sectional views showing a composite bump disposed on a substrate according to one preferred embodiment of the present invention.
FIG. 2 is a graph showing the relation between the warpage and the coefficient of thermal expansion of a compliant body.
FIG. 3 is a graph showing the relation between the contact stress and the coefficient of thermal expansion of a compliant body.
FIG. 4 is a graph showing the relation between the warpage and the Young's modulus of a compliant body.
FIG. 5 is a graph showing the relation between the contact stress and the Young's modulus of a compliant body.
FIG. 6 is a table analyzing the material parameters (including the coefficient of thermal expansion and the Young's modulus) of an integrated compliant body on the bonding effect.
FIG. 7 is a schematic cross-sectional view of a hemispherical bump according to the present invention.
FIG. 8 is a schematic cross-sectional view of a composite bump with a roughened surface according to the present invention.
FIGS. 9 through 11 are schematic cross-sectional views showing a composite bump with different types of protrusion arrangements.
FIGS. 12A through 12I are schematic cross-sectional views showing the steps for fabricating a composite bump according to the present invention.
FIGS. 13A through 13J are schematic cross-sectional views showing the steps for fabricating a composite bump with a substrate conductive layer according to the present invention.
FIGS. 14 through 16 are schematic cross-sectional views showing other composite bumps with a substrate conductive layer according to the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
The composite bump disclosed in the present invention can be disposed on a chip or any suitably designed carrier substrate such as a circuit board or a flexible tape. In the following embodiments, the generic name ‘substrate’ is used throughout and identical components are labeled with the same numbers.
FIGS. 1A and 1B are schematic cross-sectional views showing a composite bump disposed on a substrate according to one preferred embodiment of the present invention. The substrate 30 in FIGS. 1A and 1B has a pad 26 and a protective layer 28 thereon. The pad 26 has a diameter of about 90 μm, for example. The compliant body 32 is disposed on the pad 26 . The compliant body 32 has a thickness between about 5 μm to 25 μm. In the present embodiment, the compliant body 32 is fabricated using polymer material such as polyimide or epoxy-based polymer material, for example. Obviously, in other embodiments of the present invention, other materials having similar properties can be used to fabricate the compliant body 32 .
In addition, an outer conductive layer 36 covers the compliant body 32 . The outer conductive layer 36 can be fabricated using a metallic material such as aluminum or nickel, or an alloy such as nickel/gold, chromium/gold, chromium/silver or titanium/platinum. Obviously, the outer conductive layer 36 can also be an adhesion/barrier/conductor composite layer such as a chromium/copper/gold, chromium/nickel/gold, chromium/silver/gold, titanium/platinum/gold, titanium/palladium/gold or titanium/tungsten/silver composite layer. As shown in FIG. 1B , if solder bonding is required, then the outer conductive layer 36 may further include a solder layer 52 such as a lead-tin (PbSn), an indium-gallium (InGa) or an indium-tin (InSn) solder layer.
To avoid the thermal stress resulting from a coefficient of thermal expansion (CTE) mismatch, the CTE of the compliant body 32 is specially designed. FIG. 2 is a graph showing the relation between the warpage and the coefficient of thermal expansion of the compliant body 32 . FIG. 3 is a graph showing the relation between the contact stress and the coefficient of thermal expansion of the compliant body 32 . As shown in FIGS. 2 and 3 , if a lower degree of warpage is required or a higher contact stress is demanded to enhance the bonding strength, the compliant body 32 has to be fabricated using a material having a smaller CTE. Thus, based on the aforementioned analysis, the CTE of the compliant body 32 in the present invention is set within a preferable range of between 5 ppm/° C. and 200 ppm/° C. to produce the optimum effect. In fact, the preferred range for the CTE should be between 10 ppm/° C. and 150 ppm/° C.
In addition, the Young's modulus of the compliant body 32 also has some effect on the bonding effect. Hence, the Young's modulus of the compliant body 32 can be selected to increase the bonding effect and achieve an optimal design. FIG. 4 is a graph showing the relation between the warpage and the Young's modulus of the compliant body 32 . FIG. 5 is a graph showing the relation between the contact stress and the Young's modulus of the compliant body 32 . As observed from FIGS. 4 and 5 , if the amount of warpage needs to be minimized, the compliant body 32 should be fabricated using a material having a small Young's modulus. If the contact stress needs to be higher, the compliant body 32 should be fabricated using a material having a larger Young's modulus.
FIG. 6 is a table analyzing the material parameters (including the coefficient of thermal expansion and the Young's modulus) of the compliant body 32 on the bonding effect. With the aforementioned selection of the CTE in the preferred range and due consideration regarding the effect of the Young's modulus of the compliant body 32 on the bonding effect, the Young's modulus of the compliant body 32 is between 0.1 GPa and 2.8 GPa or between 3.5 GPa and 20 GPa. If the Young's modulus of the compliant body 32 is chosen to be between 0.1 GPa and 2.8 GPa, the warpage is lowered although the contact stress is smaller. On the other hand, if the Young's modulus of the compliant body 32 is chosen to be between 3.5 GPa and 20 GPa, the contact stress is increased to enhance bonding strength. Therefore, the present invention permits an amendment for the contact stress through a proper selection of the Young's modulus for the compliant body 32 .
Beside the composite bump shown in FIGS. 1A and 1B , the present invention also provide other composite bumps having different shapes and dispositions. FIG. 7 is a schematic cross-sectional view of a hemispherical bump according to the present invention. The surface of the compliant body 32 away from the pad 26 is a curve surface, for example. FIG. 8 is a schematic cross-sectional view of a composite bump with a roughened surface according to the present invention. The surface of the compliant body 32 away from the pad 26 has a roughened surface, for example. FIG. 9 is schematic cross-sectional view of a composite bump having a plurality of protrusions thereon. The compliant body 32 comprises a plurality of protrusions and the protrusions are disposed on the pad 26 . Similarly, FIGS. 10 and 11 are schematic cross-sectional views showing a composite bump with a plurality of protrusions. The protrusions in FIG. 10 are disposed on both the pads 26 and the peripheral region of the pad 26 , but the protrusions in FIG. 11 are disposed on the peripheral region of the pad 26 only.
FIGS. 12A through 12I are schematic cross-sectional views showing the steps for fabricating a composite bump according to the present invention. First, as shown in FIG. 12A , a substrate 30 having a pad 26 and a protective layer 28 thereon is provided. The pad 26 has a diameter of about 90 μm, for example. Furthermore, the surface of the pad 26 has been etched and cleaned.
As shown in FIG. 12B , a compliant material layer 32 is formed over the substrate 30 . The compliant material layer 32 is fabricated using the aforementioned polymer material, for example. In the present embodiment, the compliant material layer 32 is a non-photosensitive material such as non-photosensitive polyimide or epoxy-based polymer material having a thickness between about 5˜25 μm.
As shown in FIG. 12C , a patterned photoresist layer 40 is formed over the compliant material layer 32 above the pad 26 . As shown in FIG. 12D , using the photoresist layer 40 as a mask, the compliant material layer 32 is etched to form a compliant body 32 . The process of etching the compliant material layer 32 to form the compliant body 32 is more thoroughly described in chapter 8 of the book “Polyimides” written by Wilson, Stenzenberger and Hergenrother.
As shown in FIG. 12E , the photoresist layer 40 is removed. As shown in FIG. 12F , an outer conductive material layer 36 is formed globally over the substrate 30 . The outer conductive material layer 36 is, for example, a chromium/gold alloy layer comprising a chromium layer with a thickness of about 500 Å and a gold layer with a thickness of about 2000 Å. The outer conductive material layer 36 can also be a single metal layer of aluminum or nickel, or an alloyed layer of nickel/gold, chromium/silver or titanium/platinum. Furthermore, the outer conductive layer material 36 can also be an adhesion/barrier/conductive composite layer including, for example, chromium/copper/gold, chromium/nickel/gold, chromium/silver/gold, titanium/platinum/gold, titanium/palladium/gold or titanium/tungsten/silver.
As shown in FIG. 12G , another patterned photoresist layer 40 is formed over the outer conductive material layer 36 . As shown in FIG. 12H , using the photoresist layer 40 as a mask, the outer conductive material layer 36 is etched to form an outer conductive layer 36 . Thereafter, as shown in FIG. 12I , the photoresist layer 40 is removed to produce a composite bump.
The composite bump in the aforementioned embodiment can further include a substrate conductive layer 38 (as shown in FIG. 13J ) disposed between the compliant body 32 and the substrate 30 and extended into the peripheral area of the pad 26 above the protective layer 28 . Therefore, the compliant body 32 is able to extend outside the pad 26 and the outer conductive layer 36 covering the compliant body 32 connects with the substrate conductive layer 38 . The substrate conductive layer 38 is fabricated using aluminum, for example.
FIGS. 13A through 13J are schematic cross-sectional views showing the steps for fabricating a composite bump with the substrate conductive layer 38 according to the present invention. In the figures, a detailed explanation of previously described components (for example, material, thickness or processing parameters) is omitted in the following, and refers to the previous embodiment when necessary. First, as shown in FIG. 13A , a substrate 30 having a pad 26 and a protective layer 28 thereon is provided. As shown in FIG. 13B , a substrate conductive layer 38 is formed over the substrate 30 . The substrate conductive layer 38 is fabricated using a metallic material including aluminum or other suitable conductive material, for example. Then, as shown in FIGS. 13C˜13I , the steps necessary for fabricating the compliant body 32 and the outer conductive layer 36 as in the previous embodiment are carried out. In the process of etching the conductive material layer 36 as in FIGS. 13H and 13I , the substrate conductive material layer 38 is also etched. After removing the photoresist layer 40 , a composite bump like the one shown in FIG. 13J is formed.
The foregoing embodiment disclosed a method that uses non-photosensitive material to fabricate the compliant body. Obviously, the present invention also permits the use of photosensitive material in the fabrication of the compliant body. Since most of the steps have been described in detail in the previous embodiments, a detailed description is not repeated here.
In the following, several other types of composite bumps with substrate conductive layer fabricated according to the present invention are also illustrated as shown in FIGS. 14 through 16 . In FIG. 14 , a composite bump having a solder layer 52 formed over the outer conductive pad layer 36 is shown. In FIG. 15 , the surface of the compliant body away from pad 26 is a curve surface. In FIG. 16 , the surface of the compliant body away from the pad 26 is a roughened surface. Since the material, thickness and method of fabrication of the components in the present embodiments are closely related to the aforementioned embodiments, a detailed description is omitted.
In summary, the composite bump in the present invention mainly has a compliant body for providing a stress buffering effect. Furthermore, because the coefficient of thermal expansion of the compliant body is chosen to be within a preferred range, thermal stress is significantly relieved to increase the bonding effect. In addition, the Young's modulus of the compliant body can be specially designed to strike a balance between the contact stress and its corresponding peeling stress. Thus, a higher production yield can be obtained. Moreover, the present invention also permits a modification of the shape and disposition of the composite bump to produce an optimum design.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents. | A composite bump suitable for disposing on a substrate pad is provided. The composite bump includes a compliant body and an outer conductive layer. The coefficient of thermal expansion (CTE) of the compliant body is between 5 ppm/° C. and 200 ppm/° C. The outer conductive layer covers the compliant body and is electrically connected to the pad. The compliant body can provide a stress buffering effect for a bonding operation. Furthermore, by setting of the CTE of the compliant body within a preferable range, damages caused by thermal stress are reduced while the bonding effect is enhanced. | 20,765 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a digital filter for use in, for example, filtering of image data or the like.
2. Description of the Prior Art
A filter of symmetric coefficients having linear phase characteristic is generally employed as a finite impulse response or FIR digital filter. For the filter coefficients of the FIR digital filter, in general, a value of the coefficient of the central tap is large and values of the coefficients at the ends are small. Therefore, when the filter operations are performed using multipliers of the same input word length while aligning the digits, in the case of the filter operation using a small filter coefficient for an output of the tap at the end, the operation word length of the multiplier cannot be effectively used, so that the operation word length becomes vain.
Practically speaking, in the case where a numeric value is expressed by a fixed point method whereby a sign bit is expressed by the MSB and a decimal point appears immediately after the MSB, when the word length of a coefficient h 1 of a large value assumes m bits, the effective word length of a coefficient h 2 of a small value is n bits, which are smaller than the word length of the coefficient h 1 . Thus, (m-n) bits corresponding to the difference between the word lengths of the coefficients h 1 and h 2 become the vain word length. Assuming that the input word length of the multiplier is m bits and an input data x 1 is m bits, the case of multiplying the data x 1 by the coefficients h 1 and h 2 , respectively, will be now considered. In the multiplication of the input data x and the coefficient h 1 of a large value, both word lengths of the input data x 1 and the coefficient h 1 are equal to the input word length of the multiplier, so that the operation word length does not become vain. In the multiplication of the input data x 1 and the coefficient h 2 of a small value, however, the effective word length of the coefficient h.sub. 2 is expressed by n bits smaller than m bits of the input word length of the multiplier, so that (m-n) bits become the vain word length. Consequently, in the case where the output data of the taps which are multiplied by the coefficients in this manner are added the portions of the respective high order bits become the vain word lengths.
To prevent such vain word lengths, such constitution that the digits of the outputs of the taps are aligned as mentioned above is not used but another method is considered in the multiplication of the input data x 1 and the coefficient h 2 whereby the coefficient h 2 of a small value is shifted by (m-n) bits to the higher order so as to be increased by 2.sup.(m-n) times and supplied to the multiplier. In this way, by scaling the coefficient h 2 of a small value and supplying it to the multiplier the effective word length of the coefficient becomes long and the multiplication output of the multiplier becomes all effective bits, so that the vain operation word length is eliminated.
However, the outputs of the taps which are multiplied by the scaled coefficients- respectively have a drawback such that their .digits are not aligned by the amounts commensurate with the scaling. Therefore, it is necessary upon addition to shift the multiplied outputs of the respective taps by the amounts commensurate with the scaling so as to align their digits and then add those shifted outputs.
As described above, by supplying the scaled coefficients as inputs for multiplication, the vain operation word length is eliminated in the case where the FIR digital filter is constituted providing the multipliers of the same word length for the respective taps. However, since the filter coefficients differ for every characteristic of the filter, amounts of scaling of the multipliers also differ for every characteristic of the filter. In the case of realizing the digital filter in which the scaled coefficients are supplied as inputs for multiplication as mentioned above, different hardware must be provided for every characteristic of the digital filter, which is generally constituted by a hard-wired system for processing an image signal or the like, since the addition after the multiplication is accompanied by a bit shifting operation.
OBJECTS AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a digital filter in which hardware are not needed to be changed for every characteristic of the filter.
Another object of the invention is to provide a digital filter in which the vain operation word lengths of multipliers are eliminated.
According to the present invention, a digital filter comprising, an input terminal provided . with an input digital signal, a delay circuit connected to the input terminal and for producing a plurality of delayed digital signals each having different delay time with respect to the input digital signal, a first circuit for selectively adding the input digital signal and/or the plurality of delayed digital signals to be multiplied with one or more digital coefficient signals of same value so as to produce one or more added digital signals, a circuit for multiplying the one or more respective digital coefficient signals to the one or more added digital signals and/or one or more of the plurality of delayed digital signals, respectively a plurality of multiplied digital signals, a second circuit for adding the plurality of multiplied digital signals so as to produce an output digital signal, and a circuit connected between the delay circuit and a circuit for multiplying and for increasing the one or more added digital signals and/or the one or more of the plurality of delayed digital signals in the value thereof by one or more predetermined numbers of times, whereby the one or more respective digital coefficient signals have inversely proportional values corresponding to the one or more predetermined numbers of times of the values of the one or more added digital signals and/or the one or more of the plurality of delayed digital signals.
Further, a digital filter comprising, an input terminal provided with an input digital signal, a plurality of frame delay circuits connected to the input terminal in series, first digital adding circuits selectively connected to the input terminal or respective outputs of the plurality of frame delay circuits at inputs thereof, respectively, a plurality of line delay circuits connected to an output of the first digital adding circuits in series, second digital adding circuits selectively connected to the output of the first digital adding circuits or respective outputs of the plurality of line delay circuits at inputs thereof, respectively, a plurality of sample delay circuits connected to an output of the second digital adding circuits in series, third digital adding circuits selectively connected to the output of the second digital signal adding circuits or respective outputs of the plurality of sample delay circuits at inputs thereof, respectively, a plurality of multiplying circuits connected to outputs of the third digital adding circuits, respectively, and for multiplying a plurality of digital coefficient signals to the output signal of the third digital adding circuit, respectively, a fourth digital adding circuit connected to the outputs of the plurality of multiplying circuits at inputs thereof, respectively, and an output terminal connected to the output of the fourth digital adding circuit.
The above and other objects and advantages of the present invention will be more apparent from the following detailed description in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram showing how FIGS. 1A, 1B and 1C are assembled to form a block diagram showing an example of an arrangement of a three-dimensional digital filter;
FIG. 2 is a diagram showing how FIGS. 2A and 2B are assembled to form a block diagram showing an embodiment of the present invention;
FIG. 3 is a schematic diagram for use in explanation of one embodiment of the invention;
FIG. 4 is a schematic diagram showing an example of filter coefficients of a three-dimensional digital filter; and
FIG. 5 is a schematic diagram showing an example of coefficients in one embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
One embodiment of the present invention will now be described hereinbelow with reference to the drawings. This embodiment is applied to, for example, filtering of a non-interlaced image data.
When the frame is advanced together with the time, it is assumed that the coordinate in the direction of the frame is l, the coordinate in the vertical direction is m, and the coordinate in the horizontal direction is n, and an attention is now paid to a pixel x (l, m, n). When an image data is transmitted through an FIR digital filter having an impulse response within a range of 2L+1 samples in the frame direction, 2M+1 samples in the vertical direction, and 2N+1 samples in the horizontal direction, an output (l, m, n) with respect to the pixel x (l, m, n) from the filter becomes ##EQU1## Where, h (i, j, k) is an impulse response, namely, a filter coefficient of this three-dimensional filter.
Since an image signal is generated by a horizontal scan and a vertical scan the pixel x expressed by the coordinate function can be one-dimensionally expressed by a time function as follows.
x (l, m, n)=x (lF+mH+n)
Where, F is a vertical scan period and H is a horizontal scan period. Therefore, the three-dimensional FIR digital filter for an image signal can be realized by an arrangement shown in FIG. 1.
In FIG. 1, frame delay circuits 2 and 3 are cascade connected. An input terminal 1 is connected to one end of the frame delay circuit 2. A junction of the terminal 1 and delay circuit 2 is connected to one end of cascade connected line delay circuits 4 and 5. A junction of the delay circuits 2 and 3 is connected to one end of cascade connected line delay circuits 6 and 7. The other end of the delay circuit 3 is connected to one end of cascade connected line delay circuits 8 and 9.
An output at the junction of the input terminal and frame delay circuit 2 is supplied to a sum-of-products circuits which is constituted by: cascade connected sample delay circuits 10 to 13; multipliers 14 to 18 to which outputs of taps of the delay circuits 10 to 13 are supplied; and an adder 19 to which outputs of the multipliers 14 to 18 are supplied. The multipliers 14 to 18 serve to multiply filter coefficients h (1, 1, 2), h (1, 1, 1), h (1, 1, 0), h (1, 1, -1), and h (1, 1, -2), respectively.
An output of the line delay circuit 4 is supplied to a sum-of-products circuit which is constituted by: cascade connected sample delay circuits 20 to 23; multipliers 24 to 28 to which outputs of taps of the delay circuits 20 to 23 are supplied; and an adder 29 to which outputs of the multipliers 24 to 28 are supplied. The multipliers 24 to 28 serve to multiply filter coefficients h (1, 0, 2), h (1, 0, 1), h (1, 0, 0), h (1, 0, -1), and h (1, 0, -2), respectively.
An output of the line delay circuit 5 is supplied to a sum-of-products circuit which is constituted by: cascade connected sample delay circuits 30 to 33; multipliers 34 to 38 to which outputs of taps of the delay circuits 30 to 33 are supplied; and an adder 39 to which outputs of the multipliers 34 to 38 are supplied. The multipliers 34 to 38 serve to multiply filter coefficients h (1, -1, 2), h (1, -1, 1), h (1, -1, 0), h (1, -1, -1), and h (1, -1, -2), respectively.
An output at the junction of the frame delay circuits 2 and 3 is supplied to a sum-of-products circuit which is constituted by: cascade connected sample delay circuits 40 to 43; multipliers 44 to 48 to which outputs of taps of the delay circuits 40 to 43 are supplied; and an adder 49 to which outputs of the multipliers 44 to 48 are supplied. The multipliers 44 to 48 serve to multiply filter coefficients h (0, 1, 2), h (0, 1, 1), h (0, 1, 0), h (0, 1, -1), and h (0, 1, -2), respectively.
An output of the line delay circuit 6 is supplied to a sum-of-products circuit which is constituted by: cascade connected sample delay circuits 50 to 53; multipliers 54 to 58 to which outputs of taps of the delay circuits 50 to 53 are supplied; and an adder 59 to which outputs of the multipliers 54 to 58 are supplied. The multipliers 54 to 58 serve to multiply filter coefficients h (0, 0, 2), h (0, 0, 1), h (0, 0, 0), h (0, 0, -1), and h (0, 0, -2), respectively.
An output of the line delay circuit 7 is supplied to a sum-of-products circuit which is constituted by: cascade connected sample delay circuits 60 to 63; multipliers 64 to 68 to which outputs of taps of the delay circuits 60 to 63 are supplied; and an adder 69 to which output of the multipliers 64 to 68 are supplied. coefficients h (0, -1, 2), h (0, -1, 1), h (0, -1, 0), h (0, -1, -1), and h (0, -1, -2), respectively.
An output of the frame delay circuit 3 is supplied to a sum-of-products circuit which is constituted by: cascade connected sample delay circuits 70 to 73; multipliers 74 to 78 to which outputs of taps of the delay circuits 70 to 73 are supplied; and an adder 79 to which outputs of the multipliers 74 to 78 are supplied. The multipliers 74 to 78 serve to multiply filter coefficients h (-1, 1, 2), h (-1, 1, 1), h (-1, 1, 0), h (-1, 1, -1), and h (-1, 1, -2), respectively.
An output of the line delay circuit 8 is supplied to a sum-of-products circuit which is constituted by: cascade connected sample delay circuits 80 to 83; multipliers 84 to 88 to which outputs of taps of the delay circuits 80 to 83 are supplied; and an adder 89 to which outputs of the multipliers 84 to 88 are supplied. The multipliers 84 to 88 serve to multiply filter coefficients h (-1, 0, 2), h (-1, 0, 1), h (-1, 0, 0), h (-1, 0, -1), and h (-1, 0, -2), respectively.
An output of the line delay circuit 9 is supplied to a sum-of-products circuit which is constituted by: cascade connected sample delay circuits 90 to 93; multipliers 94 to 98 to which outputs of taps of the delay circuits 90 to 93 are supplied; and an adder 99 to which outputs of the multipliers 94 to 98 are supplied. The multipliers 94 to 98 serve to multiply filter coefficients h (-1, -1, 2), h (-1, -1, 1), h (-1, -1, 0), h (-1, -1, -1), and h (-1, -1, -2), respectively.
Outputs of the adders 19, 29, 39, 49, 59, 69, 79, 89, and 99 are supplied to an adder 100. An output terminal 101 is led out from the adder 100 and a filter output is derived from the output terminal 101.
In the three-dimensional digital filter which is used for an image signal, a filter of linear phase characteristic is often employed. The filter of the linear phase characteristic is a filter in which impulse responses are symmetrical with regard to the horizontal, vertical, and frame directions, namely, filter coefficients are symmetrical. In FIR filters having such symmetrical filter coefficients, it has been known that the number of multipliers can be reduced by multiplying the filter coefficients after preliminarily adding both data to be multiplied by same filter coefficient.
FIG. 2 shows an embodiment of the present invention. This embodiment intends to reduce the number of multipliers by using the symmetrical property of the filter coefficients as mentioned above.
In FIG. 2, frame delay circuits 202 and 203 are cascade connected. An input terminal 201 is connected to one end of the delay circuit 202. A digital image signal of, e.g., eight bits is supplied from the input terminal 201. Filter coefficients regarding tap outputs in the frame direction which are derived from the cascade connected delay circuits 202 and 203 are symmetrical. An output of the delay circuit 203 and an output at a junction of the input terminal 201 and delay circuit 202 are therefore supplied to an adder 204 so that the tap outputs in the frame direction to which the same filter coefficient is multiplied are preliminarily added.
Line delay circuits 205 and 206 are cascade connected and an output of the adder 204 is supplied to the delay circuit 205. Filter coefficients regarding the tap outputs in the vertical direction which are obtained from the cascade connected delay circuits 205 and 206 are symmetrical. The outputs of the delay circuit 206 and adder 204 are therefore supplied to an adder 207 so that the tap outputs in the vertical direction to which the same filter coefficient is multiplied are preliminarily added.
Sample delay circuits 208 to 211 are cascade connected. An output of the adder 207 is supplied to the delay circuit 208. Filter coefficients regarding the tap outputs in the horizontal direction which are obtained from the cascade connected delay circuits 208 to 211 are symmetrical. The outputs of the delay circuit 211 and adder 207 are therefore supplied to an adder 212 and the outputs of the delay circuits 210 and 208 are supplied to an adder 213 so that the outputs to which the same filter coefficient is multiplied are preliminarily added. An output of the adder 212 is supplied to a multiplier 214. An output of the adder 213 is supplied to a multiplier 215. The output of the delay circuit 209 is doubled and supplied to a multiplier 216. In this case, the parallel output of the sample delay circuit 209 may be shifted to the higher order by one bit and supplied to the multiplier or a bit shifter 209a may be separately provided. The multipliers 214, 215, and 216 serve to multiply filter coefficients h (1, 1, 2), h (1, 1, 1), and h (1, 1, 0), respectively. The filter coefficient h (1, 1, 0) is 1/2 of the inherent coefficient. Outputs of the multipliers 214, 215, and 216 are supplied to an adder 217. Sample delay circuits 218 to 221 are cascade connected. The output of the delay circuit 205 is supplied to the delay circuit 218. Filter coefficients regarding the tap outputs in the horizontal direction which are derived from the cascade connected sample delay circuits 218 to 221 are symmetrical. An output of the sample delay circuit 221 and the output of the line delay circuit 205 are therefore supplied to an adder 222, and outputs of the delay circuits 220 and 218 are supplied to an adder 223 so that the outputs to which the same filter coefficient is multiplied are preliminarily added. An output of the adder 222 is doubled and supplied to a multiplier 224. An output of the adder 223 is doubled and supplied to a multiplier 225. The output of the delay circuit 219 is increased by four times and supplied to a multiplier 226. The multipliers 224, 225, and 226 serve to multiply filter coefficients h (1, 0, 2), h (1, 0, 1), and h (1, 0, 0), respectively. The filter coefficients h (1, 0, 2) and h (1, 0, 1) are 1/2 of the inherent coefficients. The filter coefficient h (1, 0, 0) is 1/4 of the inherent coefficient. Outputs of the multipliers 224 to 226 are supplied to an adder 227. In the above case, a process similar to the sample delay circuit 209 may be performed to those outputs, respectively. However, in the case where the output which is obtained at the junction of the line delay circuits 205 and 206 is shifted by one bit to a higher order by a bit shifter 205a and the output of the sample delay circuit 219 is shifted by one bit to a higher order by a bit shifter 219a, a result similar to the above can be derived.
Line delay circuits 228 and 229 are cascade connected. The output of the frame delay circuit 202 is supplied to the delay circuit 228. Filter coefficients regarding the tap outputs in the vertical direction which are derived from the cascade connected line delay circuits 228 and 229 are symmetrical. The output of the line delay circuit 229 and the output of the frame delay circuit 202 are therefore supplied to an adder 230 so that the tap outputs in the vertical direction to which the same filter coefficient is multiplied are preliminarily added.
Sample delay circuits 231 to 234 are cascade connected. An output of the adder 230 is supplied to the delay circuit 231 Filter coefficients regarding the tap outputs in the horizontal direction which are obtained from the cascade connected delay circuits 231 to 234 are symmetrical. The output of the sample delay circuit 234 and the output of the adder 230 are therefore supplied to an adder 235, and the outputs of the delay circuits 233 and 231 are supplied to an adder 236 so that the outputs to which the same filter coefficient is multiplied are preliminarily added. An output of the adder 235 is doubled and supplied to a multiplier 237. An output of the adder 236 is doubled and supplied to a multiplier 238. The output of the delay circuit 232 is increased by four times and supplied to a multiplier 239. The multipliers 237, 238, and 239 serve to multiply filter coefficients h (0, 1, 2), h (0, 1, 1), and h (0, 1, 0), respectively. The filter coefficients h (0, 1, 2) and h (0, 1, 1) are 1/2 of the inherent coefficients. The filter coefficient h (0, 1, 0) is 1/4 of the inherent coefficient. Outputs of the multipliers 237, 238, and 239 are supplied to an adder 240. In the above case as well, a process similar to the sample delay circuit 209 may be performed to those outputs, respectively. However, in the case where the output which is obtained at the junction of the frame delay circuits 202 and 203 is shifted by one bit to a higher order by a bit shifter 202a at the output of the sample delay circuit 232 is shifted by one bit to a higher order by a bit shifter 232a, a result similar to the above can be derived.
Sample delay circuits 241 to 244 are cascade connected. The output of the line delay circuit 228 is supplied to the delay circuit 241. Filter coefficients regarding the tap outputs in the horizontal direction which are derived from the cascade connected sample delay circuits 241 to 244 are symmetrical. The outputs of the sample delay circuit 244 and line delay circuit 228 are therefore supplied to an adder 245. And the outputs of the sample delay circuits 243 and 241 are supplied to an adder 246 so that the outputs to which the same filter coefficient is multiplied are preliminarily added. An output of the adder 245 is increased by four times and supplied to a multiplier 247. An output of the adder 246 is increased .by four times and supplied to a multiplier 248. The output of the sample delay circuit 242 is increased by eight times and supplied to a multiplier 249. The multipliers 247 to 249 serve to multiply filter coefficients h (0, 0, 2), h (0, 0, 1), and h (0, 0, 0), respectively. The filter coefficients h (0, 0, 2) and h (0, 0, 1 ) are 1/4 of the inherent coefficients The filter coefficient h (0, 0, 0) is 1/8 of the inherent coefficient. Outputs of the multipliers 247 to 249 are supplied to an adder 250. In the above case as well, a process similar to the sample delay circuit 209 may be performed to those outputs, respectively. However, in the case where the outputs which are obtained at the junctions of the frame delay circuits 202 and 203 and of the line delay circuits 228 and 229 are shifted by one bit to a higher order by bit shifters 202a and 228a and the output of the sample delay circuit 242 is shifted by one bit to a higher order by a bit shifter 242a, a result similar to the above can be derived.
Outputs cf the adders 217, 227, 240, and 250 are supplied to an adder 251. An output terminal 252 is led out from the adder 251. A filter output is taken out from the output terminal 252.
As described above, with an arrangement in which data to be multiplied with the same filter coefficient is preliminarily added by using a symmetrical property of the filter coefficients, the input data of the multiplier to multiply the filter coefficient of the central tap among the input data of the multipliers to multiply the filter coefficients is not preliminarily added. Therefore in the conventional apparatus the effective word length is reduced as compared with the other input data. Thus, the effective word lengths of the input data for the filter coefficients have weights as shown in FIG. 3.
Namely, for example, when data each consisting of eight bits are added to each other the addition output is increased by one digit and becomes a data of nine bits. In this manner, the word length of the output data of the adder is longer by one bit than the effective word length of the input data. Therefore, assuming that a digital signal of, e.g., eight bits is supplied from the input terminal 201, the effective word lengths of the data which are respectively supplied to the multipliers 214 to 216, 224 to 226, 237 to 239, and 247 to 249 become as shown below.
The effective word length of the data which is supplied to the multiplier 214 is increased by three bits and becomes eleven bits since it is supplied through the adders 204, 207, and 212. The effective word length of the data which is supplied to the multiplier 215 is increased by three bits and becomes eleven bits since it is supplied through the adders 204, 207, and 213. The effective word length of the data which is supplied to the multiplier 216 is increased by two bits and becomes ten bits since it is supplied through the adders 204 and 207.
The effective word length of the data which is supplied to the multiplier 224 is increased by two bits and becomes ten bits since it is supplied through the adders 204 and 222. The effective word length of the data which is supplied to the multiplier 225 is increased by two bits and becomes ten bits since it is supplied through the adders 204 and 223. The effective word length of the data which is supplied to the multiplier 226 is increaded by one bit and becomes nine bits since it is supplied through the adder 204.
The effective word length of the data which is supplied to the multiplier 237 is increased by two bits and becomes ten bits since it is supplied through the adders 230 and 235. The effective word length of the data which is supplied to the multiplier 238 is increased by two bits and becomes ten bits since it is supplied through the adders 230 and 236. The effective word length of the data which is supplied to the multiplier 239 is increased by one bit and becomes nine bits since it is supplied through the adder 230.
The effective word length of the data which is supplied to the multiplier 247 is increased by one bit and becomes nine bits since it is supplied through the adder 245. The effective word length of the data which is supplied to the multiplier 248 is increased by one bit and becomes nine bits since it is supplied through the adder 246. The effective word length of the data which is supplied to the multiplier 249 is eight bits since it is not supplied through any adder.
As described above, by multiplying the input data of different effective word lengths using the multipliers of the same operation word length in a manner such that the digits of the output data from the multiplier are aligned, the high order bits of the operation word length cannot be effectively used in the case of the input data of a short effective word length. Therefore in the present invention the scaling of the input data is performed thereby to align the MSB of the input data and the MSB of the input for multiplication.
In other words, the data which has the weight of the effective word lengh of 1/8 is increased by eight times by shifting it by three bits. The data which has the weight of the effective word length of 1/4 is increased by four times by shifting it by two bits. The data which has the weight of the effective word length of 1/2 is doubled by shifting it by one bit. In this way, the MSB of all input data are aligned.
In this embodiment, the multipliers of the same input word length of, e.g., eleven bits are used as the multipliers 214 to 216, 224 to 226, 237 to 239, and 247 to 249. Therefore, the input data of the multiplier 249 is increased by eight times and supplied to the multiplier 249. The input data of the multipliers 226, 239, 247, and 248 are respectively increased by four times and supplied to the multipliers 226, 239, 247, and 248. The input data of the multipliers 216, 226, 225, 237, and 238 are respectively doubled and supplied to the multipliers 216, 224, 225, 237, and 238. In this manner, the effective word lengths of all input data are set to, for example, eleven bits which are equal to the input word length of the multipliers.
When the multiplication inputs are scaled and supplied as described above, the digits of the multiplied outputs are not aligned. To correct this, the digits of the multiplication outputs are aligned by reversely scaling the filter coefficients by amounts commensurate with the scaling of the input data. Practically speaking the filter coefficient regarding the data which has the weight of the word length of 1/8 is set to the coefficient of 1/8. The filter coefficient regarding the data which has the weight of the word length of 1/4 is set to the coefficient of 1/4. The filter coefficient regarding the data which has the weight of the word length of 1/2 is set to the coefficient of 1/2. Thus, the digits of the multiplication outputs can be aligned.
In this embodiment, the coefficient of the multiplier 249 is 1/8. The coefficients of the multipliers 226, 239, 247, and 248 are decreased 1/4, respectively. The coefficients of the multipliers 216, 224, 225, 237, and 238 are 1/2, respectively. In this way, the digits of the multiplication outputs are aligned. Consequently, the outputs of the multipliers 214 to 216, the outputs of the multipliers 224 to 226, the outputs of the multipliers 237 to 239, and the outputs of the multipliers 247 to 249 are supplied to the adders 217, 227, 240, and 250 without shifting the digits, respectively, and are added.
In general, values of the filter coefficients at the ends of the impulse response are small and values of the filter coefficients near the center are large. Since the data of the central tap has a small weight of the word length as input data for the multiplication, by reversely scaling the filter coefficients as mentioned above, the values of the coefficients approach to each other and the word lengths of the coefficients are almost aligned. Consequently, even in the case of the filter coefficient of a small value at the end, the operation word length ca be effectively used without making it vain.
FIG. 4 shows an example of filter coefficients of a three-dimensional digital filter. In the case of constituting a filter of filter coefficients shown in FIG. 4 by using this embodiment, the coefficients are scaled in accordance with the weights shown in FIG. 3 and supplied to the multipliers, so that they become coefficients shown in FIG. 5. The coefficients shown in FIG. 5 are coefficients which were multiplied by the weights and thereafter increased by eight times for easy comparison with the filter coefficients shown in FIG. 4.
As shown in FIG. 5, values of the coefficients are nearly equal. Therefore, when multipliers of similar input word lengths are used as multipliers to multiply the coefficients, the vain operation word length of the multipliers are not caused.
According to the present invention, the values of the coefficients which are supplied to the multipliers to multiply the filter coefficients are almost equalized and the word lengths of the filter coefficients are nearly equalized. Therefore, even in the case of performing the filter operation of the tap of a small filter coefficient as well, the vain operation word length is not caused. Further, there is no need to execute the scaling in accordance with the filter coefficients and the digits of the outputs of the multipliers are coincident. Thus, there is no need to change hardware for every characteristic of the filter.
Although the present invention has been shown and described with respect to a preferred embodiment, various change and modification which are obvious to a person skilled in the art to which the invention pertains are deemed to lie within the spirit and scope of the invention. | A digital filter has an input terminal provided with an input digital signal. A delay circuit connected to the input terminal produces a plurality of delayed digital signals each having a different delay time with respect to the input digital signal. A first circuit adds the input digital signal and/or the plurality of delayed digital signals to one or more digital coefficient signals of the same value so as to produce one or more added digital signals. A circuit multiplies the one or more respective digital coefficient signals by the one or more added digital signals and/or one or more of the plurality of delayed digital signals to produce a plurality of multiplied digital signals. A second circuit adds the plurality of multiplied digital signals to produce an output digital signal, and a circuit connected between the delay circuit and a multiplying circuit increases the one or more added digital signals and/or the one or more of the plurality of delayed digital signals by one or more predetermined numbers of times, whereby the one or more respective digital coefficient signals have inversely proportional values corresponding to the one or more predetermined numbers of times of the values of the one or more added digital signals and/or the one or more of the plurality of delayed digital signals. | 32,543 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No. 10/382,467, filed Mar. 6, 2003, now allowed, which claims the benefit of a foreign priority application filed in Japan on Mar. 6, 2002 as Ser. No. 2002-059903, all of which are incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to techniques for a semiconductor integrated circuit and its driving method. The invention also relates to a light emitting device that has a semiconductor integrated circuit of the present invention in its driving circuit portion and a pixel portion, in particular, an active matrix light emitting device which has a semiconductor integrated circuit of the present invention as a signal line driving circuit in a driving circuit portion, which has a plurality of pixels arranged so as to form a matrix pattern, and which has a switching element and a light emitting element in each of the pixels.
2. Description of the Related Art
In recent years, development of light emitting devices using self-luminous light emitting elements has progressed. Making good use of advantages such as high quality image, thinness and lightweightness, such light emitting devices are widely used in display screens of mobile phones and personal computers. In particular, light emitting devices using light emitting elements are characteristic in that they have suitably fast response speed for animated displays, and low voltage and low power consumption driving. Thus, light emitting devices using light emitting elements are expected to be widely used for various purposes, including new-generation mobile telephones and personal digital assistants (PDAs) and are attracting attention as the next-generation displays.
An example of a light emitting element is an organic light emitting diode (OLED) with an anode and a cathode, and has a structure in which an organic compounded layer is sandwiched between the aforementioned anode and cathode. The organic compound layer generally has a laminate structure of which is represented by a laminate structure of “hole transport layer, light emitting layer, and electron transport layer”, proposed by Tang, Eastman Kodak Company.
In order to make a light emitting element emit light, the semiconductor device which drives the light emitting element is formed of polysilicon (polycrystalline silicon) which has a large ON current. The amount of current that flows into the light emitting element and the luminescence of the light emitting element are in direct proportion to each other, whereby the light emitting element emits light having luminescence in accordance with the amount of current which flows to the organic compound layer. Also, as the semiconductor device that drives the light emitting element, a polysilicon transistor formed of polysilicon is used.
However, when displaying a multi-gray scale image using a light emitting device with a light emitting element, a method of driving the device such as an analog gray scale method (analog driving method), or a digital gray scale method (digital driving method) can be given. The difference between the two lies in their methods of controlling the light emitting element in the state of light emission or non-light emission. The former analog gray scale method uses an analog method of controlling the current that flows into the light emitting element thereby obtaining gray scale. The latter digital gray scale method uses a method in which the light emitting element is driven in only two states, an ON state (almost 100% luminescence), and an OFF state (almost 0% luminescence).
Further, proposed is a current input method with which it is possible to classify the type of signal that is inputted into the light emitting device using the light emitting element as an example. In this current input method, it is supposed control of the amount of current that flows to the light emitting element is possible without being influenced by the TFT which drives the light emitting element.
The current input method is applicable to both the analog gray scale method and the digital gray scale method mentioned above. The current input method is a method where a video signal inputted into a pixel is a current and the luminescence of the light emitting element can be controlled by flowing current according to the inputted video signal (current) into the light emitting element.
Next, an example of a circuit construction of a pixel using a current input method and a driving method thereof in light emitting device will be explained with reference to FIG. 14 . In FIG. 14 , a pixel has a signal line 1401 , first to third scanning lines 1402 to 1404 , a power source line 1405 , transistors 1406 to 1409 , a capacitor element 1410 , and light emitting element 1411 . A current source circuit 1412 is provided to the signal line.
The transistor 1406 has a gate electrode connected to the first scanning line 1402 . A first electrode of the transistor 1406 is connected to the signal line 1401 whereas its second electrode is connected to a first electrode of the transistor 1407 , a first electrode of the transistor 1408 , and a first electrode of the transistor 1409 . The transistor 1407 has a gate electrode connected to the second scanning line 1403 . A second electrode of the transistor 1407 is connected to a gate electrode of the transistor 1408 . A second electrode of the transistor 1408 is connected to the current line 1405 . The transistor 1409 has a gate electrode connected to the third scanning line 1404 . A second electrode of the transistor 1409 is connected to one of electrodes of the light emitting element 1411 . The capacitor element 1410 is connected between the gate electrode and second electrode of the transistor 1408 to hold the gate-source voltage of the transistor 1408 . The current line 1405 and a cathode of the light emitting element 1411 receive given electric potentials to hold an electric potential difference with each other.
Operations from video signal writing to light emission will be described next. First, pulses are inputted to the first scanning line 1402 and the second scanning line 1403 to turn the transistors 1406 and 1407 ON. A signal current flowing in the signal line 1401 at this point is denoted by I data and is supplied from the current source circuit 1412 .
Right after the transistor 1406 is turned ON, no electric charges are held in the capacitor element 1410 yet and therefore the transistor 1408 remains OFF. In other words, a current caused by electric charges accumulated already in the capacitor element 1410 alone is flowing at this point.
Thereafter, electric charges are gradually accumulated in the capacitor element 1410 to cause a difference in electric potential between the electrodes. As the electric potential difference between the electrodes reaches a threshold Vth of the transistor 1408 , the transistor 1408 is turned ON to generate a current flow. The current flowing into the capacitor element 1410 then is gradually reduced. However, the reduced current does not stop ongoing accumulation of electric charges in the capacitor element 1410 .
Accumulation of electric charges in the capacitor element 1410 continues until the electric potential difference between its two electrodes, namely, the gate-source voltage of the transistor 1408 , reaches a given voltage, which is a voltage (V GS ) high enough to cause the current I data to flow in the transistor 1408 . When the accumulation of electric charges is finished, the current I data continues to flow in the transistor 1408 . A signal writing operation is conducted as above. Lastly, the first scanning line 1402 and the second scanning line 1403 stop being selected to turn the transistors 1406 and 1407 OFF.
A light emission operation follows next. A pulse is inputted to the third scanning line 1404 to turn the transistor 1409 ON. With the transistor 1408 turned ON by V GS which is written in the preceding operation and kept in the capacitor 1410 , a current flows from the current source line 1405 . This causes the light emitting element 1411 to emit light. If the transistor 1408 is set to operate in a saturation range at this point, a light emission current I EL flowing in the light emitting element 1411 does not deviate from I data even when the source-drain voltage of the transistor 1408 is changed.
As described above, the current input method refers to a method in which a drain current whose current value is equal to or in proportion to the signal current value set by the current source circuit 1412 flows between the source and drain of the transistor 1408 and the light emitting element 1411 emits light with a luminance according to the drain current. By employing a current input method pixel as the one described in the above, influence of fluctuation in characteristic between transistors that constitute the pixel can be reduced and a desired current can be supplied to its light emitting element. Other current input method pixel circuits have been reported in U.S. Pat. No. 6,229,506 B1 and JP 2001-147659 A.
In a light emitting device employing the current input method, a signal current exactly reflecting a video signal has to be inputted to a pixel. However, when polysilicon transistors are used to build a driving circuit that inputs a signal current to a pixel (the circuit corresponds to the current source circuit 1412 in FIG. 14 ), characteristic fluctuation between the polysilicon transistors leads to fluctuation in signal current and unevenness in an image displayed. The characteristic fluctuation is caused by defects in crystal growth direction and grain boundaries, nonuniformity in thickness of the laminate, and insufficient accuracy in patterning a film. Because of large fluctuation between the polysilicon transistors, it is difficult to generate an accurate signal current and an image displayed will be full of streaks running vertically.
In other words, influence of characteristic fluctuation between transistors constituting a driving circuit that inputs a signal current to a pixel has to be reduced in a light emitting device employing the current input method. This means that influence of characteristic fluctuation has to be reduced both in transistors that constitute the driving circuit and in transistors that constitute a pixel.
SUMMARY OF THE INVENTION
The present invention has been made in view of the above problems, and an object of the present invention is therefore to provide a semiconductor integrated circuit which reduces influence of transistor characteristic fluctuation between current sources of a current source circuit until the transistor characteristics do not affect the circuit, as well as a method of driving the semiconductor integrated circuit.
Another object of the present invention is to provide a light emitting device having a driving circuit portion that has the semiconductor integrated circuit and a pixel portion.
Particularly, an object of the present invention is to provide an active matrix light emitting device which has the semiconductor integrated circuit as a signal line driving circuit in a driving circuit portion, which has a plurality of pixels arranged so as to form a matrix pattern, and which has a switching element and a light emitting element in each of the pixels.
Another object of the present invention is to provide a light emitting device in which semiconductor elements of a pixel portion and driving circuit portion are composed of polysilicon thin film transistors to integrally form the pixel portion and the driving circuit portion on the same substrate.
A current source circuit is composed of one or more current sources. One current source has one or more transistors. A current source that supplies a constant current is called a constant current source.
A semiconductor integrated circuit of the present invention is characterized by having signal lines, a current source circuit that outputs a current to be inputted to the signal lines, and means for switching current source circuits connected to the signal lines each time a given period passes (hereinafter simply referred to as switching means. The switching means has a plurality of circuits that have a switching function, and therefore is also called a switching circuit).
The switching means of the present invention switches current sources connected to signal lines and accordingly switches currents inputted to the signal lines at given intervals even when there is fluctuation in current outputted from the current source circuit. Therefore, the amount of current flowing into a light emitting element, namely, the luminance, is seemingly evened out over time and display unevenness can be solved. A light emitting device that is not influenced by transistor characteristic fluctuation is thus provided.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawings:
FIG. 1 is a diagram showing the structure of a semiconductor integrated circuit of the present invention;
FIG. 2 is a diagram showing the structure of a semiconductor integrated circuit of the present invention;
FIG. 3 is a diagram showing the structure of a semiconductor integrated circuit of the present invention;
FIG. 4 is a timing chart of a signal line driving method of the present invention;
FIG. 5 is a diagram showing the structure of a semiconductor integrated circuit of the present invention;
FIG. 6 is a diagram showing the structure of a semiconductor integrated circuit of the present invention;
FIG. 7 is a diagram showing the structure of switching means in a semiconductor integrated circuit of the present invention;
FIG. 8 is a diagram showing the structure of a semiconductor integrated circuit of the present invention;
FIG. 9 is a diagram showing the structure of a semiconductor integrated circuit of the present invention;
FIG. 10 is a diagram showing the structure of a semiconductor integrated circuit of the present invention;
FIGS. 11A to 11C are timing charts of a signal line driving method of the present invention;
FIGS. 12A and 12B are diagrams showing the structure of a light emitting device of the present invention;
FIGS. 13A and 13B are diagrams showing the structure of a semiconductor integrated circuit of the present invention;
FIG. 14 is a circuit diagram of a pixel of a light emitting device; and
FIGS. 15A to 15H are diagrams showing electronic equipment to which a light emitting device of the present invention is applied.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Embodiment Mode
An outline of a semiconductor integrated circuit of the present invention, as a signal line driving circuit, will be described with reference to FIG. 6 . For easy understanding, FIG. 6 focuses on three current sources C(i), C(i+1), and C(i+2) of a current source circuit and on a signal line S(m) for supplying a current to a pixel.
As shown in FIG. 6 , the current sources C(i), C(i+1), and C(i +2) are connected to the signal line S(m) through switching means. The present invention is characterized in that the switching means chooses a current to be inputted to the signal line S(m) out of a current I(i), a current I(i+1), and a current I(i+2) from the three current sources C(i) to C(i+2) and switches from one current to another each time a given period passes.
The switching means is described next. FIG. 7 shows the structure of the switching means. The current sources C(i), C(i+1), and C(i+2) respectively have characteristics that make the currents I(i), I(i+1), and I(i+2) to flow. The current sources C(i), C(i+1), and C(i+2) are placed such that they can be connected to the signal line S(m) through a switch. A signal is inputted to the switch and, according to the signal, the switch connects the signal line S(m) to one of the current sources C(i), C(i+1), and C(i+2).
When the switch establishes a connection with the current source C(i), the current I(i) flows into the signal line S(m). When the switch establishes a connection with the current source C(i+1), the current I(i+1) flows into the signal line S(m). When the switch connects with the current source C(i+2), the current I(i+2) flows into the signal line S(m). In short, the current to be flown into the signal line S(m) is switched among I(i), I(i +1), and I(i+2).
The example illustrated by FIGS. 6 and 7 focuses on one signal line and three current sources for easy understanding. However, an actual signal line driving circuit has plural signal lines and current sources as shown in the following embodiments. The switch serving as the switching means in FIG. 7 has a terminal but, in practice, the switching function is provided by an analog switch or like other circuits as shown in the following embodiments.
A period for switching within this given period is very short. Therefore, an image displayed seems uniform to the human eye even when there is difference in characteristics between current sources, namely, fluctuation in current supplied from a current source.
With the switching means described above, the present invention obtains a semiconductor integrated circuit having a current source circuit which is not influenced by transistor characteristics. This makes it possible to provide a light emitting device which can supply a desired signal current to a light emitting element and which can display an image with no unevenness.
To generalize the present invention using a function, the present invention is a semiconductor integrated circuit, comprised of: m signal lines S 1 , S 2 , . . . , and S m ; a current source circuit that has i current sources C 1 , C 2 , . . . , and C i ; and switching means that includes n switching units U 1 , U 2 , . . . , and U n , the circuit characterized in that: the n switching units are each connected to j current sources out of the i current sources; and the M-th signal line S M is connected to the N-th switching unit U N , and the switching unit U N is connected to the F 1 (N)-th current source, the F 2 (N)-th current source, the F 3 (N)-th current source, . . . , and the F j (N)-th current source which satisfy a function F k (x)(k=1˜j, x=1−n).
The present invention is a semiconductor integrated circuit, comprised of: m signal lines S 1 , S 2 , . . . , and S m ; a current source circuit that has i current sources C 1 , C 2 , . . . , and C i ; and switching means that includes n switching units U 1 , U 2 , . . . , U n , and the circuit characterized in that: the n switching units are each connected to j current sources out of the i current sources; the M-th signal line S M is connected to the N-th switching unit U N , and the switching unit U N is connected to the F 1 (N)-th current source, the F 2 (N)-th current source, the F 3 (N)-th current source, . . . , and the F j (N)-th current source which satisfy a function F k (x)(k=1˜j, x=1˜n); and the (M−1)-th signal line S M−1 is connected to the (N−1)-th switching unit U N−1 , and the switching unit U N−1 is connected to the F 1 (N−1)-th current source, the F 2 (N−1)-th current source, the F 3 (N−1)-th current source, . . . , and the F j (N−1)-th current source which satisfy the function F k (x).
In the present invention, adjacent switching units can share a current source. Using the above function, this is expressed as the current sources satisfying F 3 (N)=F 2 (N+1)=F 1 (N+2) when i=3, for example. In other words, adjacent switching units can share the N-th current source, the (N+1)-th current source, and the (N+2)-th current source. To give another example, current sources satisfy F 5 (N)=F 4 (N+1)=F 3 (N+2)=F 4 (N+3)=F 5 (N+4) when i=5, and adjacent switching units can share the N-th, (N+1)-th, (N+2)-th, (N+3)-th, and (N+4)-th current sources.
As described, the present invention allows switching units to share current sources. This eliminates the border between one signal line and its adjacent signal line and makes a uniform current to flow in all signal lines. As a result, no border is formed in any part of the display screen to make it possible to provide a light emitting device with no streaks in a displayed image and no luminance unevenness.
The present invention solves characteristic fluctuation among elements used in a semiconductor integrated circuit, and can provide the same effect when the elements whose characteristic fluctuation is to be controlled are transistors other than polysilicon transistors, for example, single crystal silicon transistors.
Embodiment 1
In this embodiment, a semiconductor integrated circuit of the present invention is applied to a signal line driving circuit of a driving circuit portion and a specific description is given on a structure and driving method of a current source circuit of the signal line driving circuit.
A specific example of the present invention is shown in FIG. 1 . The description given in this embodiment deals with current sources constituted of n-channel transistors. A transistor can take either the n-channel polarity or the p-channel polarity and, commonly, the polarity of a transistor is determined by the polarity of a pixel. When a current flows from a pixel toward a current source circuit, the polarity is desirably the n type. When a current flows from a current source circuit to a pixel, the polarity is desirably the p type. This is because fixing the source electric potential of a transistor is convenient.
Shown in FIG. 1 are transistors Tr(i) to Tr(i+5), switching means, and signal lines S(m) to S(m+5). The transistors Tr(i) to Tr(i+5) constitute current sources C(i) to C(i+5), respectively. Gate electrodes of the transistors Tr(i) to Tr(i+5) are connected to a current control line and their source electrodes are connected to V SS . The current value is controlled by the voltage applied to the current control line.
The gate electrodes of the transistors Tr(i) to Tr(i+5) here are connected to the same current control line for simplification. However, the transistors may be connected to different current control lines to have different current values by applying different levels of voltage to the current control lines. In this case, different transistors output currents to different destinations and voltages applied to the current control lines have to be switched in accordance with a switch in destination.
If the transistors Tr(i) to Tr(i+5) have an identical characteristic, currents I(i) to I(i+5) are equal to one another. In reality, however, characteristic fluctuation among the transistors Tr(i) to Tr(i+5) is large and therefore the currents I(i) to I(i+5) are varied. The switching means of the present invention chooses a current to be inputted to a signal line out of the currents I(i) to I(i+5) and switches from one to another each time a given period passes. Accordingly, a current flowing in a light emitting element is also switched at given intervals. As a result, to the human eye, light emission is evened out over time and unevenness in luminance is reduced.
FIG. 2 shows the structure of the switching means having analog switches (also called transfer gates). In FIG. 2 , components identical with those in FIG. 1 are denoted by the same symbols. The circuit is designed such that drain electrodes of the transistors Tr(i) to Tr(i+5) are connected to the signal lines S(m) to S(m+5). However, one signal line can be connected to three current sources. By a switching function, one out of three current sources is chosen for one signal line.
For example, when a signal for selecting a terminal 1 is inputted to the switching means, the signal line S(m+1) is connected to the current source C(i), the signal line S(m+2) is connected to the current source C(i+1), and the subsequent signal lines and current sources are connected in a similar fashion. Next, a signal for selecting a terminal 2 is inputted to the switching means to connect the signal line S(m+1) to the current source C(i+1) and the signal line S(m+2) to the current source C(i+2), and the subsequent signal lines and current sources are connected in a similar fashion. Next, a signal for selecting a terminal 3 is inputted to the switching means to connect the signal line S(m+1) to the current source C(i+2) and the signal line S(m+2) to the current source C(i+3), and the subsequent signal lines and current sources are connected in a similar fashion. Currents from three current sources are thus alternately inputted to one signal line, thereby avoiding uneven display.
To generalize this connection using the function that expresses the present invention, the current sources are set so as to satisfy F 1 (N)=N+a, F 2 (N)=N+b, and F 3 (N)=N+c (a, b, and c are integers and a≠b≠c) when i=3, and a=−1, b=0, and c=1.
FIG. 3 shows a specific example in which analog switches are used for the switching means having a switching function. In FIG. 3 , components identical with those in FIG. 2 are denoted by the same symbols, and the current sources C(i) to C(i+5) have the transistors Tr(i) to Tr(i+5), respectively.
Denoted by A(l) to A(l+2) and A(l)b to A(l+2)b in FIG. 3 are wires connected to plural analog switches. The analog switches are divided into groups and a group of analog switches is connected to one signal line (switching unit). In FIG. 3 , switching units U(n) to U(n+5) each have three analog switches and, are connected to the signal lines S(m) to S(m+5), respectively. The switching units together form the switching means.
In the current source C(i+1), the drain electrode of the transistor Tr(i+1) is connected to one of the analog switches of the switching unit U(n+1), one of the analog switches of the switching unit U(n), and one of the analog switches of the switching unit U(n +2). In short, a drain electrode of a transistor is connected to one analog switch chosen from each of three switching units. The rest of the current sources, C(i), C(i+2), C(i+3), C(i+4), and C(i+5), are similarly connected to their respective analog switches.
When signals are inputted to the wires A(l) and A(l+1)b, an analog switch to be connected is chosen and turned conductive. Then a current flows from the current source connected with the selected analog switch to a signal line, for example, from the current source C(i+1) to the signal line S(m+2). Similarly, currents flow from the current sources C(i+1), C(i+3), C(i+4), C(i+5), and C(i+6) to the signal lines S(m), S(m+2), S(m+3), S(m+4), and S(m+5), respectively. This is referred to as Selection ( 1 ).
Next, signals are inputted to the wires A(l+1) and A(l+1)b and an analog switch to be connected is chosen and turned conductive. Then a current flows from the current source connected with the selected analog switch to a signal line, for example, from the current source C(i+1) to the signal line S(m+1). Similarly, currents flow from the current sources C(i+1), C(i+3), C(i+4), C(i+5), and C(i+6) to the signal lines S(m+1), S(m+3), S(m+4), S(m+5), and S(m+6), respectively. Though not shown in FIG. 3 , the current source C(i +6) is the current source to the right of the current source C (i+5). This is referred to as Selection ( 2 ).
Next, signals are inputted to the wires A(l+2) and A(l+2)b and an analog switch to be connected is chosen to turn it conductive. Then a current flows from the current source connected with the selected analog switch to a signal line, for example, from the current source C(i+1) to the signal line S(m). Similarly, currents flow from the current sources C(i +1), C(i+3), C(i+4), C(i+5), and C(i+6) to the signal lines S(m−1), S(m+1), S(m+2), S(m+3), and S(m+4), respectively. Though not shown in FIG. 3 , the signal line S(m−1) is the signal line to the left of the signal line S (m). This is referred to as Selection ( 3 ).
Selections ( 1 ) to ( 3 ) are repeated at given intervals. In this way, an image displayed is made seemingly uniform even when the current inputted from the current sources C(i) to C(i+5) to the signal lines S(m) to S(m+5) is fluctuated.
The switching period in the signal line driving circuit of the present invention is described with reference to a timing chart of FIG. 4 . F 1 to F 3 in FIG. 4 denote first to third frame periods, respectively, and it takes one frame period for a light emitting device to display one image. One frame period is usually set to about 1/60 second in order to prevent flicker from being recognized by the human eye. A(l) to A(l+2) and A(l)b to A(l+2)b in FIG. 4 represent electric potentials of signals inputted to the wires A(l) to A(l+2) and A(l)b to A(l+2)b.
A switching period in which the electric potential of a signal inputted to A(l) is High (H) and the electric potential of a signal inputted to A(l)b is Low (L) is set in the first frame period F 1 . In this switching period, analog switches that are connected to the wires A(l) and A(l)b are turned conductive and currents are inputted from the transistors that are connected with the now-conductive analog switches to signal lines. Accordingly, only one analog switch out of each switching unit is turned conductive.
A switching period in which the electric potential of a signal inputted to A(l+1) is High (H) and the electric potential of a signal inputted to A(l+1)b is Low (L) is set in the second frame period F 2 . In this switching period, analog switches that are connected to the wires A(l+1) and A(l+1)b are turned conductive and currents are inputted from the transistors that are connected with the now-conductive analog switches to signal lines.
A switching period in which the electric potential of a signal inputted to A(l+2) is High (H) and the electric potential of a signal inputted to A(l+2)b is Low (L) is set in the third frame period F 3 . In this switching period, analog switches that are connected to the wires A(l+2) and A(l+2)b are turned conductive and currents are inputted from the transistors that are connected with the now-conductive analog switches to signal lines.
The frame periods F 1 to F 3 are repeated to allow the switching means to switch currents flowing into the signal lines S(m) to S(m+5) in order.
The description given in this embodiment deals with a structure in which the power supply line connected to a current source having an n type transistor is Vss and a current flows from a pixel to Vss. However, the polarity of the transistor is set in accordance with the polarity of the pixel as mentioned above. Accordingly, if the circuit takes a structure in which a current flows toward a pixel, the power supply line is Vdd and the transistor of the current source is given the p type conductivity.
Described next is a case in which a current source has a DA conversion function. This current source makes a current source circuit that outputs a current having analog values of 8 gray scales when a 3-bit digital video signal is inputted, for example.
FIG. 5 shows a specific circuit structure of such a current source circuit. As shown in FIG. 5 , each current source has three transistors, Tr 1 (i), Tr 2 (i), and Tr 3 (i). The ratio of W (gate width)/L (gate length) of the three transistors Tr 1 (i), Tr 2 (i), and Tr 3 (i) is set to 1:2:4. Then, with the same gate voltage applied to the transistors Tr 1 (i), Tr 2 (i), and Tr 3 (i), the ratio of currents flowing in the transistors is 1:2:4. In short, the ratio of currents supplied from one current source is 1:2:4 and the amount of current can be controlled in 2 3 =8 stages. Accordingly, the current source circuit can output a current having analog values of 8 gray scales from a 3-bit digital video signal.
Which of the transistors Tr 1 (i), Tr 2 (i), and Tr 3 (i) will be turned ON or OFF is controlled by controlling the voltage applied to their gates. This way the current value of currents outputted from the current sources C(i) to C(i+5) can be controlled. However, combinations of the currents from the current sources C(i) to C(i+5) and the signal lines S(m) to S(m+5) are varied by the switching means. Therefore voltages applied to the transistors Tr 1 (i), Tr 2 (i), and Tr 3 (i) of each of the current sources C(i) to C(i+5) have to be switched in accordance with a switch in combination.
By giving a current source a DA conversion function as above, an image can be displayed in gray scales with high accuracy. The bit number can be set to suit individual cases and transistors are designed in accordance with the set bit number.
In a light emitting device that uses the above-described signal line driving circuit of the present invention, display unevenness of pixels is reduced visually and the light emitting device can display a uniform image having no unevenness. The present invention can provide a uniform image with no display unevenness also when a signal is inputted through an external circuit to a signal line if the present invention is applied to the external circuit.
Furthermore, the present invention makes it possible to reduce the size and weight of a light emitting device if semiconductor elements of its signal line driving circuit are polysilicon transistors. This is because polysilicon transistors can be used for semiconductor elements of a pixel portion thereof and accordingly the pixel portion and a peripheral circuit portion that includes the signal line driving circuit can be formed integrally on the same substrate. When a pixel portion and a peripheral circuit portion are integrally formed on the same substrate, no external circuit is necessary. Since complex processes for connecting an external circuit to signal lines and failed connection can be avoided, the reliability of the light emitting device is improved by the present invention.
Embodiment 2
In the present invention, the number of current sources (columns of current sources) or the position of current sources (current source column number) may be asymmetric as long as one signal line is connected to 2 or more current sources. This embodiment shows as examples different structures for connection between switching units of switching means, signal lines, and current sources than Embodiment 1.
FIG. 8 shows a structure in which current sources C(i) to C(i+5) are connected to signal lines S(m) to S(m+5) through switching means. Switching means of the present invention has a function of switching currents sent from current sources. In order to avoid complicating the drawing, the switching function is schematically illustrated in FIG. 8 to give only 3 terminals and switches.
For instance, the signal line S(m+2) can be connected to any one of the current sources C(i+2), C(i+3), and C(i+4). In short, one signal line can be connected to the closest current source and 2 adjacent current sources to the right of the closest current source. This rule is used to connect the rest of the signal lines, S(m), S(m+1), S(m+3), S(m+4), and S(m+5) to the current sources.
To generalize this connection using the function that expresses the present invention, the current sources axe set so as to satisfy F 1 (N)=N+a, F 2 (N)=N+b, and F 3 (N)=N+c (a, b, and c are integers and a≠b≠c) when i=3, and a=−2, b=−1, and c=0.
According to the connection relation between signal lines and current sources of the present invention, it is not always necessary to connect a signal line with the closest current source, namely, a current source in the closest column, but a signal line may be connected to a distant current source. A connection structure shown in FIG. 9 is given an example thereof.
In FIG. 9 , current sources C(i) to C(i+6) are connected to signal lines S(m) to S(m+6) through switching means. This switching means too has 3 terminals and switches.
For instance, the signal line S(m+2) can be connected to any one of the current sources C(i), C(i+2), and+4). In short, one signal line can be connected to the closest current source and to the current source the second from the closest current source on each side. This rule is used to connect the rest of the signal lines, S(m), S(m+1), S(m+3), S(m +4), S(m+5), and S(m+6) to the current sources.
To generalize this connection using the function that expresses the present invention, the current sources are set so as to satisfy F 1 (N)=N+a, F 2 (N)=N+b, and F 3 (N)=N+c (a, b, and c are integers and a≠b≠c) when i=3, and a=−2, b=0, and c=−2.
According to the connection relation between signal lines and current sources of the present invention, the number of current sources connected to one signal line is not limited to 3. FIG. 10 shows an example of connecting 5 current sources in one switching unit.
In FIG. 10 , current sources C(i) to C(i+6) are connected to signal lines S(m) to S(m +6) through switching means. A switching unit in this switching means has 5 terminals and switches.
For instance, the signal line S(m+2) can be connected to any one of the current sources C(i), C(i+1), C(i+2), C(i+3), and C(i+4). In short, one signal line can be connected to the closest current source and to 2 adjacent current sources on each side. This rule is used to connect the rest of the signal lines, S(m), S(m+1), S(m+3), S(m+4), and S(m+5) to the current sources.
To generalize this connection using the function that expresses the present invention, the current sources are set so as to satisfy F 1 (N)=N+a, F 2 (N)=N+b, F 3 (N)=N+c, F 4 (N) =N+d, F 5 (N)=N+e (a, b, c, d, and e are integers and a≠b≠c≠d≠e) when i=5, and a=−2, b=−1, c=0, d=1, and e=2.
A displayed image seems more uniform and unevenness is reduced more as the number of current sources that can be connected to one signal line is larger as in FIG. 10 .
In this embodiment, currents flowing into signal lines can be switched by the method described in Embodiment 1 which uses analog switches to switch current sources. This embodiment may also employ current sources that have a DA conversion function (see Embodiment 1 for details). In short, this embodiment can be combined with the switching means and current sources of Embodiment 1.
As described above, the connection relation between signal lines and current sources of the present invention allows current sources to be in asymmetric number and position as long as one signal line is connected to 2 or more current sources and currents flowing into signal lines can be switched.
Embodiment 3
This embodiment describes an example in which a light emitting device of the present invention displays an image in gray scales by dividing one frame period (a unit frame period associated with synchronization timing of a video signal inputted) into sub-frame periods (this display method is called time ratio gray scale driving display).
Time ratio gray scale driving display is explained first. In a time ratio gray scale driving method using a digital video signal (digital driving), a writing period Ta and a display period (also called a lighting period) Ts are alternately repeated in one frame period to display one image.
For example, when an image is displayed from an n-bit digital video signal, one frame period has at least n writing periods and n display periods. The n writing periods are respectively associated with n bits of the video signal and the same applies to the n display periods.
As shown in FIG. 11A , a writing period Tam (m is an arbitrary number ranging from 1 to n) is followed by a display period that is associated with the same bit number, in this case, a display period Tsm. One writing period Ta and one display period Ta constitute a sub-frame period SF. The sub-frame period consisting of the writing period Tam and the display period Tsm which are associated with the m-th bit is SFm. Lengths of the display periods Ts 1 to Tsn are set so as to satisfy Ts 1 :Ts 2 : . . . :Tsn=2 0 :2 1 : . . . :2 (n−1 ).
In each sub-frame period, whether or not a light emitting element emits light is decided based on the bit of the digital video signal. The sum of lengths of display periods in one frame period in which a light emitting element emits light is controlled to control the gray scale number.
In order to improve the quality of an image displayed, a sub-frame period having a long display period may be divided into several periods. For a specific dividing method, see Japanese Patent Application No. 2000-267164.
In this embodiment, it is desirable to switch currents flowing from current sources to signal lines in a display period of a sub-frame period. If the switch is made in a writing period, the inputted current, namely, information on whether or not a light emitting element is to emit light, may not be transferred successfully. By switching in such short a period at intervals, fluctuation in luminance of light emitting elements is further reduced and the uniformity in display is improved.
FIG. 11B shows a specific example in which a 3-bit signal is used. In FIG. 11B , one frame period has sub-frame periods SF 1 , SF 2 , and SF 3 . The sub-frame periods SF 1 , SF 2 , and SF 3 have writing periods Ta 1 , Ta 2 , and Ta 3 and display periods Ts 1 , Ts 2 , and Ts 3 , respectively. Periods in which connection between a signal line and a current source is switched (hereinafter simply referred to as switching periods) 1 , 2 , and 3 are provided in display periods Ts 1 , Ts 2 , and Ts 3 , respectively. Currents inputted from current sources to signal lines are switched in the switching periods 1 to 3 . In this way, the switch can be made in a short period at intervals and a displayed image seems more uniform.
The switching periods 1 to 3 in FIG. 11B are each put immediately before a writing period. However, a switching period can be set in any time frame as long as it is within a display period.
FIG. 11C is a timing chart of signals inputted to analog switches. In the first frame, A 1 is ON in SF 1 , A 2 is ON in SF 2 , and A 3 is ON in SF 3 . In the second frame, A 2 is ON in SF 1 , A 3 is ON in SF 2 , and A 1 is ON in SF 3 . Though not shown in FIG. 11C , it is similar for the third frame and A 3 is ON in SF 1 , A 1 is ON in SF 2 , and A 2 is ON in SF 3 .
If ON states of A 1 to A 3 in the sub-frame periods SF 1 to SF 3 are fixed (if A 1 is ON in SF 1 , A 2 is ON in SF 2 , and A 3 is ON in SF 3 throughout the first to third frames), fluctuation cannot be evened out sufficiently. Accordingly, as shown in FIG. 11C , it is desirable to vary their ON states-from one sub-frame period to another and from one frame period to another.
This embodiment is merely an example and which signal is inputted in which sub-frame period can be set to suit individual cases. For a specific method of inputting signals, see FIG. 4 .
In this embodiment, it is preferable to employ the current source circuits of Embodiment 1 which have a DA conversion function in order to raise the gray scale number. This embodiment can be combined with Embodiments 1 and 2.
Embodiment 4
This embodiment describes the structure of a light emitting device of the present invention with reference to FIG. 12 .
The light emitting device of the invention includes a pixel portion 402 having a plurality of pixels arranged in matrix on a substrate 401 , and includes a signal line driving circuit 1203 , a first scanning line driver circuit 404 and a second scanning line driver circuit 405 in the periphery of the pixel portion 402 . Although the signal line driving circuit 1203 and the two scanning line driver circuits 404 and 405 are provided in FIG. 12(A) , the present invention is not limited thereto, and may be arbitrarily designed depending on the pixel structure. Signals are supplied from the outside to the signal line driving circuit 1203 , the first scanning line driver circuit 404 and the second scanning line driver circuit 405 via FPCs 406 .
The structures and operations of the first scanning line driver 404 circuit and the second scanning line driver circuit 405 will be described using FIG. 12(B) . The first scanning line driver 404 circuit and the second scanning line driver circuit 405 each include a shift register 407 and a buffer 408 . Operations will be briefly described as: the shift register 407 sequentially outputs sampling pulses in accordance, with a clock signal (G-CLK), a start pulse (S-SP), and an inverted clock signal (G-CLKb); thereafter, the sampling pulses amplified in the buffer 408 are input to scanning lines; and the scanning lines are set to be in a selected state for each line; signal currents I data are sequentially written to pixels controlled by the selected signal lines.
Note that the structure may be such that a level shifter circuit is arranged between the shift register 407 and the buffer 408 . Disposition of the level shifter circuit enables the voltage amplitude to be increased.
The structure of the signal line driving circuit 1203 will be hereafter described. Note that this embodiment may be arbitrarily combined with Embodiment 1, 2 and 3.
Current sources provided in the signal line driving circuit of the invention may not be arranged in a straight line, but may be shifted and arranged. Further, two signal line driving circuits may be provided symmetrical to the pixel portion. That is to say, the present invention does not limit the arrangement of the current sources as long as the current sources connect to the signal lines via switching means.
Embodiment 5
In this embodiment, the detailed structure and operations of the signal line driving circuit 1203 used in the case of performing 1-bit digital gradation display will be described with reference to FIG. 13 .
FIG. 13(A) is a schematic view of the signal line driving circuit 1203 used in the case of performing 1-bit digital gradation display. The signal line driving circuit 1203 includes a shift register 1211 , a first latch circuit 1212 , a second latch circuit 1213 and a constant current circuit 1214 . The shift register 1211 , the first latch circuit 1212 and the second latch circuit 1213 function as switches used for the video signals shown in FIG. 1 .
Further, the constant current circuit 1214 is constituted by a plurality of current sources. FIG. 13(B) shows specific circuits of the shift register 1211 , the first latch circuit 1212 and the second latch circuit 1213 .
Operations will be briefly described. The shift register 1211 is constituted by, for example, a plurality of flip-flop circuits (FFs). A clock signal (S-CLK), a start pulse (S-SP) and an inverted clock signal (S-CLKb) are input therein, and sampling pulses are sequentially output in accordance with the timing of these signals.
The sampling pulses, which have been output from the shift register 1211 , are input to the first latch circuit 1212 . Digital video signals have been input to the first latch circuit 1212 , and a video signal is retained in each column in accordance with the input timing of the sampling pulse.
In the first latch circuit 1212 , upon completion of video-signal retaining operations in columns to the last column, during a horizontal return period, a latch pulse is input to the second latch circuit 1213 , and video signals retained in the first latch circuit 1212 are transferred in batch to the second latch circuit 1213 . As a result, one-line video signals retained in the second latch circuit 1213 are input to video switches at the same time. On-off operations of the video switches are carried out to control the input of the signals to the pixels, thereby displaying the gradation.
While the video signals retained in the second latch circuit 1213 are being supplied to the constant current circuit 1214 , sampling pulses are again output in the shift register 1211 . Thereafter, the operation is iterated, and one-frame video signals are processed.
In addition, Embodiment 5 can be arbitrarily combined with the inventions described in embodiments 1, 2, 3 and 4.
Embodiment 6
Electronic equipment using the light emitting device of the present invention includes, for example, video cameras, digital cameras, goggle type displays (head mount displays), navigation systems, audio reproducing devices (such as car audio and audio components), notebook personal computers, game machines, mobile information terminals (such as mobile computers, mobile phones, portable game machines, and electronic books), and image reproducing, devices provided with a recording medium (specifically, devices for reproducing a recording medium such as a digital versatile disc (DVD), which includes a display capable of displaying images). In particular, in the case of mobile information terminals, since the degree of the view angle is appreciated important, the terminals preferably use the light emitting device. Practical examples are shown in FIG. 15 .
FIG. 15(A) shows a light emitting device, which contains a casing 2001 , a support base 2002 , a display portion 2003 , a speaker portion 2004 , a video input terminal 2005 , and the like. The light emitting device of the present invention can be applied to the display portion 2003 . Further, the light emitting device shown in FIG. 15(A) is completed with the present invention. Since the light emitting device is of self-light emitting type, it does not need a back light, and therefore a display portion that is thinner than that of a liquid crystal display can be obtained. Note that light emitting devices include all information display devices, for example, personal computers, television broadcast transmitter-receivers, and advertisement displays.
FIG. 15(B) shows a digital still camera, which contains a main body 2101 , a display portion 2102 , an image receiving portion 2103 , operation keys 2104 , an external connection port 2105 , a shutter 2106 , and the like. The light emitting device of the present invention can be applied to the display portion. 2102 . Further, the digital still camera shown in FIG. 15 (B) is completed with the present invention.
FIG. 15(C) shows a notebook personal computer, which contains a main body 2201 , a casing 2202 , a display portion 2203 , a keyboard 2204 , external connection ports 2205 , a pointing mouse 2206 , and the like. The light emitting device of the present invention can be applied to the display portion 2203 . Further, the light emitting device shown in FIG. 15(C) is completed with the present invention.
FIG. 15(D) shows a mobile computer, which contains a main body 2301 , a display portion 2302 , a switch 2303 , operation keys 2304 , an infrared port 2305 , and the like. The light emitting device of the present invention can be applied to the display portion 2303 . Further, the mobile computer shown in FIG. 15(D) is completed with the present invention.
FIG. 15(E) shows a portable image reproducing device provided with a recording medium (specifically, a DVD reproducing device), which contains a main body 2401 , a casing 2402 , a display portion A 2403 , a display portion B 2404 , a recording medium (such as a DVD) read-in portion 2405 , operation keys 2406 , a speaker portion 2407 , and the like. The display portion A 2403 mainly displays image information, and the display portion B 2404 mainly displays character information. The light emitting device of the present invention can be used in the display portion A 2403 and in the display portion B 2404 . Note that family game machines and the like are included in the image reproducing devices provided with a recording medium. Further, the DVD reproducing device shown in FIG. 15(E) is completed with the present invention.
FIG. 15(F) shows a goggle type display (head mounted display), which contains a main body 2501 , a display portion 2502 , an arm portion 2503 , and the like. The light emitting device of the present invention can be used in the display portion 2502 . The goggle type display shown in FIG. 15(F) is completed with the present invention.
FIG. 15(G) shows a video camera, which contains a main body 2601 , a display portion 2602 , a casing 2603 , external connection ports 2604 , a remote control reception portion 2605 , an image receiving portion 2606 , a battery 2607 , an audio input portion 2608 , operation keys 2609 , an eyepiece portion 2610 , and the like. The light emitting device of the present invention can be used in the display portion 2602 . The video camera shown in FIG. 15(G) is completed with the present invention.
Here, FIG. 15(H) shows a mobile phone, which contains a main body 2701 , a casing 2702 , a display portion 2703 , an audio input portion 2704 , an audio output portion 2705 , operation keys 2706 , external connection ports 2707 , an antenna 2708 , and the like. The light emitting device of the present invention can be used in the display portion 2703 . Note that, by displaying white characters on a black background, the current consumption of the mobile phone can be suppressed. Further, the mobile phone shown in FIG. 15(H) is completed with the present invention.
When the emission luminance of light emitting materials are Increased in the future, the light emitting device will be able to be applied to a front or rear type projector by expanding and projecting light containing image information having been output lenses or the like.
Cases are increasing in which the above-described electronic equipment displays information distributed via electronic communication lines such as the Internet and CATVs (cable TVs). Particularly increased are cases where moving picture information is displayed. Since the response speed of the light emitting materials is very high, the light emitting device is preferably used for moving picture display.
Since the light emitting device consumes power in a fight emitting portion, information is desirably displayed so that the light emitting portions are reduced as much as possible. Thus, in the case where the light emitting device is used for a display portion of a mobile information terminal, particularly, a mobile phone, an audio playback device, or the like, which primarily displays character information, it is preferable that the character information be formed in the light emitting portions with the non-light emitting portions being used as the background.
As described above, the application range of the present invention is very wide, so that the invention can be used for electronic equipment in all of fields. The electronic equipment according to this embodiment may use the structure of the signal line driving circuit according to any one of Embodiments 1 to 5.
The present invention can provide a semiconductor integrated circuit in which influence of characteristic fluctuation between transistors in a current source circuit is reduced until the transistor characteristics do not affect the circuit, and a method of driving the semiconductor integrated circuit. The semiconductor integrated circuit of the present invention can be used in a driving circuit portion to provide a light emitting device having a pixel portion. In particular, the semiconductor integrated circuit of the present invention can be applied to a signal line driving circuit of a driving circuit portion to provide an active matrix light emitting device in which pixels are arranged so as to form a matrix pattern and each of the pixels has a switching element and a light emitting element. The present invention can also provide a light emitting device in which elements of a pixel portion and a driving circuit portion are polysilicon thin film transistors to integrally form the pixel portion and the driving circuit portion on the same substrate. | A transistor causes fluctuation in the threshold and mobility due to the factor such as fluctuation of the gate length, the gate width, and the gate insulating film thickness generated by the difference of the manufacturing steps and the substrate to be used. As a result, there is caused fluctuation in the current value supplied to the pixel due to the influence of the characteristic fluctuation of the transistor, resulting in generating streaks in the display image. A light emitting device is provided which reduces influence of characteristics of transistors in a current source circuit constituting a signal line driving circuit until the transistor characteristics do not affect the device and which can display a clear image with no irregularities. A signal line driving circuit of the present invention can prevent streaks in a displayed image and uneven luminance. Also, the present invention makes it possible to form elements of a pixel portion and driving circuit portion from polysilicon on the same substrate integrally. In this way, a display device with reduced size and current consumption is provided as well as electronic equipment using the display device. | 56,876 |
FIELD OF THE INVENTION
[0001] The invention relates to a method for producing a hardened steel part with cathodic corrosion protection, a cathodic corrosion protection, and parts comprised of steel sheets with the corrosion protection.
BACKGROUND OF THE INVENTION
[0002] Low-alloy steel sheets, particularly for vehicle body construction are not corrosion resistant after they have been produced using suitable forming steps, either by means of hot rolling or cold rolling. This means that even after a relatively short period of time, moisture in the air causes oxidation to appear on the surface.
[0003] It is known to protect steel sheets from corrosion by means of appropriate corrosion protection coatings. According to DIN 50900, Part 1, corrosion is the reaction of a metallic material with its environment, producing a measurable change in the material, and can impair the function of a metallic part or an entire system. In order to avoid corrosion damage, steel is usually protected so that it resists corrosion-inducing influences for the required length of service life. Corrosion damage prevention can be achieved by influencing the properties of the reaction partners and/or by changing the reaction conditions, by separating a metallic material from the corrosive medium through the application of protective coatings, and by means of electrochemical measures.
[0004] According to DIN 50902, a corrosion protection coating is a coating produced on a metal or in the region close to the surface of a metal and is comprised of one or more layers. Multilayer coatings are also referred to as corrosion protection systems.
[0005] Possible corrosion protection coatings include, for example, organic coatings, inorganic coatings, and metallic coatings. The reason for using metallic corrosion protection coatings is to lend the steel surface the properties of the coating material for the longest possible period of time. The selection of an effective metallic corrosion protection correspondingly requires knowledge of the corrosion-inducing chemical relationships in the system comprised of the steel, coating metal, and aggressive medium.
[0006] The coating metal can be electrochemically more noble or less noble than steel. In the first case, the respective coating metal protects the steel only by forming protective coatings. This is referred to as a so-called barrier protection. As soon as the surface of the coating metal develops pores or is damaged, a “local element” forms in the presence of moisture in which the base partner, i.e. the metal to be protected, is attacked. The more noble coating metals include tin, nickel, and copper.
[0007] On the one hand, base metals provide protective covering layers; on the other hand, since they are no more noble than steel, they are also attacked when there are breaches in their coating. If such a coating becomes damaged, then the steel is not attacked as a result, but the formation of local elements begins to corrode the base covering metal. This is referred to as a so-called galvanic or cathodic corrosion protection. The base metals include zinc, for example.
[0008] Metallic protective layers are applied by means of a variety of methods. Depending on the metal and the method, the bond with the steel surface is chemical, physical, or mechanical and runs the gamut from alloy formation and diffusion to adhesion and simple mechanical bracing.
[0009] The metallic coatings should have technological and mechanical properties similar to those of steel and should also behave similarly to steel in reaction to mechanical stresses or plastic deformations. The coatings should also not be damaged by forming and should also not be negatively affected by forming procedures.
[0010] When applying hot dipped coatings, the metal to be protected is dipped into liquid molten metal. The hot dipping produces corresponding alloy layers at the phase boundary between the steel and the coating metal. An example of this is hot-dip galvanizing.
[0011] In continuous hot-dip galvanizing, the steel band is conveyed through a zinc bath at a bath temperature of approx. 450° C. The coating thickness—typically 6-20 μm—is adjusted by means of slot nozzles (using air or nitrogen as the stripping medium) that strip off the excess zinc scooped up by the band. Hot-dip galvanized items have a high degree of corrosion resistance and good suitability for welding and forming; they are chiefly used in the construction, automotive, and household appliance industries.
[0012] It is also known to produce a coating from a zinc-iron alloy. To accomplish this, these items, after the hot-dip galvanizing, undergo a diffusion annealing at temperatures above the melting point of zinc, usually between 480° C. and 550° C. This causes the zinc-iron alloy layers to grow and the overlying zinc layer to shrink. This method is referred to as “galvannealing”. The zinc-iron alloy thus generated likewise has a high resistance to corrosion, and a good suitability for welding and forming; its chief uses are in the automotive and household appliance industries. Hot dipping can also be used to produce other coatings made of aluminum, aluminum-silicon, zinc-aluminum, and aluminum-zinc-silicon.
[0013] It is also known to produce electrolytically deposited metal coatings, which means that metallic coatings comprised of electrolytes are deposited in an electrolytic fashion, i.e. with current passing through.
[0014] Electrolytic coating can also be used for metals that cannot be applied using the hot dipping method. Electrolytic coatings usually have layer thicknesses of between 2.5 and 10 μm and are generally thinner than hot-dipped coatings. Some metals such as zinc also permit the production of thick-layered coatings using the electrolytic coating method. Electrolytically galvanized sheets are primarily used in the automotive industry; because of their high surface quality, these sheets are chiefly used to construct the outer body. They have a good forming capacity, are suitable for welding, store well, and have matte surfaces to which paint adheres well.
[0015] Particularly in the automotive field, there is a constant push toward ever lighter raw vehicle bodies. On the one hand, this is because lighter vehicles consume less fuel; on the other hand, raw vehicle bodies need to be lighter in order to offset the weight of the ever more numerous auxiliary functions and auxiliary units with which modem vehicles are being equipped.
[0016] At the same time, however, safety requirements for motor vehicles are becoming more and more stringent; the vehicle body must assure the safety of the passengers in the vehicle and protect them in the event of an accident. It has therefore become necessary to provide a higher level of accident safety with lighter vehicle body weights. This can only be achieved by using materials with an increased strength, particularly in the region of the passenger compartment.
[0017] In order to achieve the required levels of strength, it is necessary to use steel types with improved mechanical properties or to treat the steel types used in order to provide them with the necessary mechanical properties.
[0018] In order to produce steel sheets with an increased strength, it is known to form steel parts and simultaneously harden them in a single step. This method is also referred to as “press hardening”. In this process, a steel sheet is heated to a temperature above the austenitization temperature, usually above 900° C., and then formed in a cold die. The die forms the hot steel sheet, which, due to its contact with the surfaces of the cold die, cools very rapidly so that the known hardening effects occur in the steel. It is also known to first form the steel sheet and then cool and harden the formed sheet steel part in a calibration press. By contrast with the first method, this has the advantage that the sheet is formed in the cold state, which makes it possible to achieve more complex shapes. In both methods, however, the heating causes scaling to occur on the surface of the sheet, so that after the forming and hardening, the surface of the sheet must be cleaned, for example by means of sandblasting. Then, the sheet is cut to size and if need be, the necessary holes are punched into it. In this case, it is disadvantageous that the sheets have a very high degree of hardness at the time they are mechanically machined, thus making the machining process expensive, in particular incurring a large amount of tool wear.
[0019] The object of U.S. Pat. No. 6,564,604 B2 is to produce steel sheets that then undergo a heat treatment and to create a method for manufacturing parts by hardening these coated steel sheets. In spite of the temperature increase, this approach is intended to assure that the steel sheet is not decarburized and the surface of the steel sheet does not oxidize before, during, or after the hot pressing or heat treatment. To this end, an alloyed, intermetallic mixture is applied to the surface before or after the punching, which should provide protection from corrosion and decarburizing and can also provide a lubricating function. In one embodiment form, the above-mentioned patent proposes using a conventional zinc layer that is clearly applied electrolytically; the intent is for this zinc layer, along with the steel substrate, to transform into a homogeneous Zn—Fe alloy in a subsequent austenitization of the sheet substrate. This homogeneous layer structure is verified by means of microscopic images. This coating should have a mechanical resistance that protects it from melting, thus contradicting earlier assumptions. In practice, however, such a property is not apparent. In addition, the use of zinc or zinc alloys should offer a cathodic protection to the edges if cuts are present. In this embodiment form, however, contrary to the contentions in the above-mentioned patent, a coating of this kind disadvantageously provides hardly any cathodic corrosion protection at the edges and in the region of the sheet metal surface and provides only poor corrosion protection in the event that the coating is damaged.
[0020] In the second example in U.S. Pat. No. 6,564,604 B2, a coating is disclosed, which is composed of 50% to 55% aluminum and 45% to 50% zinc, possibly with small quantities of silicon. A coating of this kind is not novel in and of itself and is known by the brand name Galvalume®. According to the above-mentioned patent, the coating metals zinc and aluminum should combine with iron to form a homogeneous zinc-aluminum-iron alloy coating. The disadvantage of this coating is that it no longer achieves a sufficient cathodic corrosion protection; but when it is used in the press hardening process, the predominantly barrier-type protection that it provides is also insufficient due to inevitable surface damage in some regions. In summary, the method described in the above patent is unable to solve the problem that in general, zinc-based cathodic corrosion coatings are not suitable for protecting steel sheets, which, after being coated, are to be subjected to a heat treatment and possibly an additional shaping or forming step.
[0021] EP 1 013 785 A1 has disclosed a method for producing a sheet metal part in which the surface of the sheet is to be provided with an aluminum coating or an aluminum alloy coating. A sheet provided with coatings of this kind should be subjected to a press hardening process; possible coating alloys disclosed include an alloy containing 9-10% silicon, 2-3.5% iron, and residual aluminum with impurities, and a second alloy with 2-4% iron and the residual aluminum with impurities. Coatings of this kind are intrinsically known and correspond to the coating of a hot-dip aluminized sheet steel. A coating of this kind has the disadvantage that it only achieves a so-called barrier protection. The moment a barrier protection coating of this kind is damaged or when fractures occur in the Fe—Al coating, the base material, in this case the steel, is attacked and corrodes. No cathodic protection is provided.
[0022] It is also disadvantageous that when the steel sheet is heated to the austenitization temperature and undergoes the subsequent press hardening step, even a hot-dip aluminized coating is subjected to such chemical and mechanical stress that the finished part does not have a sufficient corrosion protection coating. This substantiates the view that such a hot-dip aluminized coating is not sufficiently suitable for the press hardening of complex geometries, i.e. for the heating of a steel sheet to a temperature greater than the austenitization temperature.
[0023] DE 102 46 614 A1 has disclosed a method for producing a coated structural part for the automotive industry. This method is intended to eliminate the disadvantages of the above-mentioned European patent application 1 013 785 A1. In particular, the contention therein is that by using the dipping method according to European patent application 1 013 785 A, an intermetallic phase would already have been produced during the coating of the steel and that this alloy layer between the steel and the actual coating would be hard and brittle and would fracture during cold forming. As a result, microfractures would occur to such an extent that the coating itself would come loose from the base material and consequently lose its ability to protect. According to DE 102 46 614 A1, therefore, a coating comprised of metal or a metal alloy is applied by means of at least one galvanic coating method in an organic, non-aqueous solution; according to the above-mentioned patent application, aluminum or an aluminum alloy is a particularly well-suited and therefore preferable coating material. Alternatively, zinc or zinc alloys would also be suitable. A sheet coated in this way can then undergo a cold preforming followed by a hot final forming. But this method has the disadvantage that an aluminum coating, even when it has been electrolytically applied, offers no further corrosion protection once the surface of the finished part is damaged since the protective barrier has been breached. An electrolytically deposited zinc coating has the disadvantage that when heated for the hot forming, most of the zinc oxidizes and is no longer available for a cathodic protection. The zinc vaporizes in the protective gas atmosphere.
[0024] An object of the present invention is to create a method for producing a part made of hardened steel sheet with an improved cathodic corrosion protection.
[0025] A further object of the present invention is to create a cathodic corrosion protection for steel sheets that undergo a forming and hardening.
SUMMARY OF THE INVENTION
[0026] In the method according to the present invention, a hardenable steel sheet is provided with a coating comprised of a mixture of mainly zinc and one or more high oxygen affinity elements such as magnesium, silicon, titanium, calcium, aluminum, boron, and manganese, containing 0.1 to 15% by weight of the high oxygen affinity element, and the coated steel sheet, at least in some areas, is heated to a temperature above the austenitization temperature of the sheet alloy with the admission of oxygen, and is formed before or after this; after sufficient heating, the sheet is cooled, the cooling rate being calculated to produce a hardening of the sheet alloy. The result is a hardened part made of a sheet steel that provides a favorable level of cathodic corrosion protection.
[0027] The corrosion protection for steel sheets according to the present invention, which first undergo a heat treatment and are then formed and hardened, is a cathodic corrosion protection that is essentially zinc-based. According to the invention, the zinc that comprises the coating is mixed with 0.1% to 15% of one or more high oxygen affinity elements such as magnesium, silicon, titanium, calcium, aluminum, boron, and manganese, or any mixture or alloy thereof. It has turned out that such small quantities of a high oxygen affinity element such as magnesium, silicon, titanium, calcium, aluminum, boron, and manganese achieve a surprising effect in this specific use.
[0028] According to the present invention, the high oxygen affinity elements include at least Mg, Al, Ti, Si, Ca, B, and Mn. In the following, whenever aluminum is mentioned, it is intended to also stand for all of the other elements mentioned here.
[0029] For example, the coating according to the present invention can be deposited on a steel sheet by means of so-called hot-dip galvanization, i.e. a hot-dip coating process in which a fluid mixture of zinc and the high oxygen affinity element(s) is applied. It is also possible to deposit the coating electrolytically, i.e. to deposit the mixture of zinc and the high oxygen affinity element(s) together onto the sheet surface or to first deposit a zinc coating and then in a second step, to deposit one or more high oxygen affinity elements one after another or in any mixture or alloy thereof onto the zinc surface or to deposit them onto it through vaporization or other suitable methods.
[0030] It has surprisingly turned out that despite the small quantity of a high oxygen affinity element such as aluminum, upon heating, a very effective, self-healing, superficial, and full-coverage protective layer forms, which is essentially comprised of Al 2 O 3 or an oxide of the high oxygen affinity element (MgO, CaO, TiO, SiO 2 , B 2 O 3 , MnO). This very thin oxide layer protects the underlying zinc-containing corrosion protection coating from oxidation, even at very high temperatures. This means that during the special processing of the galvanized sheet in the press hardening process, an approximately two-layered corrosion protection coating forms, which is composed of a highly effective cathodic layer with a high zinc content that is in turn protected from oxidation and vaporization by a very thin oxidation protection coating comprised of one or more oxides (Al 2 O 3 , MgO, CaO, TiO, SiO 2 , B 2 O 3 , MnO). A cathodic corrosion protection coating is thus produced that has a surprising resistance to chemical attack. This means that it is necessary to perform the heat treatment in an oxidizing atmosphere. It is in fact possible to avoid oxidation if protective gas is used (an oxygen-free atmosphere), but the zinc would then vaporize due to the high vapor pressure.
[0031] It has also turned out that the corrosion protection coating according to the invention for the press hardening process also has such a high stability that a forming step following the austenitization of the sheets does not destroy this layer. Even if microfractures develop on the hardened part, the cathodic protective action nevertheless remains more powerful than the protective action of the known corrosion protection coatings for the press hardening process.
[0032] In order to provide a sheet with the corrosion protection according to the invention, in a first step, a zinc alloy with an aluminum content of greater than 0.1 wt. % but less than 15 wt. %, in particular less than 10 wt. %, and even more preferably of less than 5 wt. %, can be applied to a steel sheet, in particular an alloyed steel sheet, and then in a second step, parts of the coated sheet can be machined out, in particular cut out or punched out, and heated to a temperature above the austenitization temperature of the sheet alloy with the admission of atmospheric oxygen and subsequently cooled at an increased speed. A forming of the part cut out from the sheet (the sheet bar) can occur before or after the sheet is heated to the austenitization temperature.
[0033] It is assumed that in the first step of the process when the sheet is being coated, a thin inhibition phase comprised in particular of Fe 2 Al 5−x Zn x forms on the sheet surface or in the proximal region of the sheet, which inhibits the Fe—Zn diffusion in a fluid metal coating process that occurs in particular at a temperature of up to 690° C. Thus in the first process step, the sheet with a zinc-metal coating and added aluminum is produced, which has an extremely thin inhibition phase only toward the sheet surface, i.e. the proximal region of the coating, that effectively prevents a rapid growth of an iron-zinc binding phase. It is also conceivable that the mere presence of aluminum reduces the tendency for iron-zinc diffusion in the region of the boundary layer.
[0034] If in the second step, the sheet provided with a zinc-aluminum-metal coating is heated to the austenitization temperature of the sheet material with the admission of atmospheric oxygen, then the metal coating on the sheet liquefies for the time being. On the distal surface, the higher oxygen affinity aluminum from the zinc reacts with atmospheric oxygen to form a solid oxide or alumina, which produces a drop in the aluminum-metal concentration in this direction, resulting in a steady diffusion of aluminum toward depletion, i.e. toward the distal region. This alumina enrichment in the coating region exposed to the air then functions as an oxidation protection for the coating metal and as a vaporization inhibitor for the zinc.
[0035] Also during heating, the aluminum is drawn by steady diffusion from the proximal inhibition phase toward the distal region and is available there to form the surface layer of Al 2 O 3 . This achieves the sheet coating production that leaves behind a highly effective cathodic coating with a high zinc content.
[0036] A suitable example is a zinc alloy with an aluminum content of greater than 0.2 wt. % but less than 4 wt. %, preferably of greater than 0.26 wt. % but less than 2.5 wt. %.
[0037] If in the first step, the application of the zinc alloy coating onto the sheet surface suitably occurs during the passage through a liquid metal bath at a temperature of greater than 425° C. but less than 690° C., in particular from 440° C. to 495° C., with subsequent cooling of the coated sheet, it is possible not only to efficiently produce the proximal inhibition phase and to achieve an observable, very good diffusion inhibition in the region of the inhibition layer, but also to improve the hot forming properties of the sheet material.
[0038] An advantageous embodiment of the invention comprises a method that uses a hot rolled or cold rolled steel band with a thickness of for example greater than 0.15 mm and with a concentration range of at least one of the alloy elements within the following weight percentage limits:
carbon up to 0.4, preferably 0.15 to 0.3 silicon up to 1.9, preferably 0.11 to 1.5 manganese up to 3.0, preferably 0.8 to 2.5 chromium up to 1.5, preferably 0.1 to 0.9 molybdenum up to 0.9, preferably 0.1 to 0.5 nickel up to 0.9, titanium up to 0.2, preferably 0.02 to 0.1 vanadium up to 0.2 tungsten up to 0.2, aluminum up to 0.2, preferably 0.02 to 0.07 boron up to 0.01, preferably 0.0005 to 0.005 sulfur max. 0.01, preferably max. 0.008 phosphorus max 0.025, preferably max. 0.01 residual iron and impurities.
[0039] The surface structure of the cathodic corrosion protection according to the invention has been demonstrated to be particularly favorable for a high degree of adhesion of paints and lacquers.
[0040] The adhesion of the coating to the sheet steel item can be further improved if the surface coating has a zinc-rich, intermetallic iron-zinc-aluminum phase and an iron-rich iron-zinc-aluminum phase, the iron-rich phase having a ratio of zinc to iron of at most 0.95 (Zn/Fe≦0.95), preferably from 0.20 to 0.80 (Zn/Fe=0.20 to 0.80), and the zinc-rich phase having a ratio of zinc to iron of at least 2.0 (Zn/Fe≧2.0), preferably from 2.3 to 19.0 (Zn/Fe=2.3 to 19.0).
[0041] Examples of the invention will be explained in greater detail below in conjunction with the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0042] FIG. 1 shows a heating curve of test sheets during annealing in a radiation furnace.
[0043] FIG. 2 shows a microscopic image of the transverse section of an annealed test specimen of a steel sheet that has been hot-dip aluminized with a method not according to the invention.
[0044] FIG. 3 shows the potential curve over the measurement time in a galvanostatic dissolution for a steel sheet that has been hot-dip aluminized with a method not according to the invention.
[0045] FIG. 4 shows a microscopic image of the transverse section of an annealed test specimen of a steel sheet with an aluminum-zinc-silicon alloy coating not according to the invention.
[0046] FIG. 5 shows the potential curve over the measurement time in a galvanostatic dissolution trial of a steel sheet with an aluminum-zinc-silicon alloy coating not according to the invention.
[0047] FIG. 6 shows a microscopic image of the transverse section of an annealed test specimen of a cathodically corrosion-protected sheet according to the invention.
[0048] FIG. 7 shows the potential curve for the sheet according to FIG. 6 .
[0049] FIG. 8 shows a microscopic image of the transverse section of an annealed test specimen of a sheet provided with a cathodic corrosion protection according to the invention.
[0050] FIG. 9 shows the potential curve for the sheet according to FIG. 8 .
[0051] FIG. 10 shows microscopic images of the surface of a sheet that has been coated according to the invention in the unhardened—not yet heat treated—state shown in FIGS. 8 and 9 in comparison to a sheet that has been coated and treated by methods not according to the invention.
[0052] FIG. 11 shows a microscopic image of the transverse section of a sheet that has been coated and treated by methods not according to the invention.
[0053] FIG. 12 shows the potential curve for the sheet not according to the invention in FIG. 11 .
[0054] FIG. 13 shows a microscopic image of the transverse section of a sheet that has been coated and heat treated according to the invention.
[0055] FIG. 14 shows the potential curve for the sheet according to FIG. 13 .
[0056] FIG. 15 shows a microscopic image of the transverse section of a steel sheet that has been electrolytically galvanized not according to the invention.
[0057] FIG. 16 shows the potential curve for the sheet according to FIG. 15 .
[0058] FIG. 17 shows a microscopic image of the transverse section of an annealed test specimen of a sheet with a zinc-nickel coating not according to the invention.
[0059] FIG. 18 shows the potential curve for the sheet not according to the invention in FIG. 17 .
[0060] FIG. 19 is a comparison of the potentials required for dissolution for the tested materials as a function of time.
[0061] FIG. 20 is a graph depicting the area used to assess the corrosion protection.
[0062] FIG. 21 is a graph depicting the different protection energies of the tested materials.
[0063] FIG. 22 is a graph depicting the different protection energies of a sheet according to the invention, under two different heating conditions.
[0064] FIG. 23 qualitatively depicts the phase formation as a “leopard pattern” in coatings according to the invention.
[0065] FIG. 24 is a flowchart depicting the possible process sequences according to the invention.
[0066] FIG. 25 is a graph depicting the distribution of the elements aluminum, zinc, and iron depending on the depth of the surface coating before the sheet is annealed.
[0067] FIG. 26 is a graph depicting the distribution of the elements aluminum, zinc, and iron depending on the depth of the surface coating after the sheet is annealed, as proof of the formation of a protective aluminum oxide skin on the surface.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0068] Approximately 1 mm thick steel sheets with a corrosion protection coating that is the same on both sides, with a layer thickness of 15 μm were manufactured and tested. The sheets were placed for 4 minutes 30 seconds in a 900° C. radiation furnace and then rapidly cooled between steel plates. The time between removal of the sheets from the furnace and the cooling between the steel plates was 5 seconds. The heating curve of the sheets during the annealing in the radiation furnace essentially followed the curve shown in FIG. 1 .
[0069] Then, the test specimens obtained were analyzed for visual and electrochemical differences. Assessment criteria here included the appearance of the annealed steel sheets and the protection energy. The protection energy is the measure for the electrochemical protection of the coating, determined by means of galvanostatic dissolution.
[0070] The electrochemical method of galvanostatic dissolution of the metallic surface coatings of a material makes it possible to classify the corrosion protection mechanism of the coating. The potential/time behavior of a coating to be protected from corrosion is ascertained at a predetermined, constant current flow. A current density of 12.7 mA/cm 2 was predetermined for the measurements. The measurement device is a three-electrode system. A platinum network was used as a counter electrode; the reference electrode was comprised of Ag/AgCl (3M). The electrolyte was comprised of 100 g/l ZnSO 4 *5H 2 O and 200 g/l NaCl, dissolved in deionized water.
[0071] If the potential required to dissolve the layer is greater than or equal to the steel potential, which can easily be determined by stripping or grinding off the surface coating, then this is referred to as a pure barrier protection without an active cathodic corrosion protection. The barrier protection is characterized in that it separates the base material from the corrosive medium.
[0072] The results of the coating examples will be described below.
EXAMPLE 1 (NOT ACCORDING TO THE INVENTION)
[0073] A hot-dip aluminized steel sheet is produced by conveying a steel sheet through a liquid aluminum bath. When annealed at 900° C., the reaction of the steel with the aluminum coating produces an aluminum-iron surface layer. The correspondingly annealed sheet has a dark gray appearance; the surface is homogeneous and does not have any visually discernible defects.
[0074] The galvanostatic dissolution of the surface coating of the hot-dip aluminized sheet must have a very high potential (+2.8 V) at the beginning of the measurement in order to assure the current density of 12.7 mA/cm 2 . After a short measurement time, the required potential falls to the steel potential. It is clear from this behavior that an annealed sheet with a coating produced by hot-dip aluminization provides very efficient barrier protection. However, as soon as holes develop in the coating, the potential falls to the steel potential and damage to the base material begins to occur. Since the potential required for the dissolution never falls below the steel potential, this represents a pure barrier layer without cathodic corrosion protection. FIG. 3 shows the potential curve over the measurement time and FIG. 2 shows a microscopic image of a transverse section.
EXAMPLE 2 (NOT ACCORDING TO THE INVENTION)
[0075] A steel sheet was covered with an aluminum-zinc coating by means of hot-dip galvanization, the molten metal being comprised of 55% aluminum, 44% zinc, and approx. 1% silicon. After the coating of the surface and a subsequent annealing at 900° C., a gray-blue surface without defects is observed. FIG. 4 depicts a transverse section.
[0076] The annealed material then undergoes the galvanostatic dissolution. At the beginning of the measurement, the material demonstrates an approx. −0.92 V potential required for dissolution, which thus lies significantly below the steel potential. This value is comparable to the potential required for dissolution of a hot-dip galvanized coating before the annealing process. But this very zinc-rich phase ends after only approx. 350 seconds of measurement time. Then there is a rapid increase to a potential that now lies just below the steel potential. After this coating is breached, the potential first falls to a value of approx. −0.54 V and then continuously rises until it reaches a value of approx. −0.35 V. Only then does it begin to gradually fall to the steel potential. Because of the very negative potential that lies significantly below the steel potential at the beginning of the measurement, in addition to the barrier protection, this material does provide a certain amount of cathodic corrosion protection. However, the part of the coating that supplies a cathodic corrosion protection is depleted after only approx. 350 seconds of measurement time. The remaining coating can only provide a slight amount of cathodic corrosion protection since the difference between the required potential for the coating dissolution and the steel potential is now only equivalent to less than 0.12 V. In a poorly conductive electrolyte, this part of the cathodic corrosion protection is no longer usable. FIG. 5 shows the potential/time graph.
EXAMPLE 3 (ACCORDING TO THE INVENTION)
[0077] A steel sheet is hot-dip galvanized in a heat melting bath of essentially 95% zinc and 5% aluminum. After annealing, the sheet has a silver-gray surface without defects. In the transverse section ( FIG. 6 ), it is clear that the coating is comprised of a light phase and a dark phase, these phases representing Zn—Fe—Al-containing phases. The light phases are more zinc-rich and the dark phases are more iron-rich. Part of the aluminum reacts to the atmospheric oxygen during annealing and forms a protective Al 2 O 3 skin.
[0078] In the galvanostatic dissolution, at the beginning of the measurement, the sheet has a potential required for dissolution of approx. −0.7 V. This value lies significantly below the potential of the steel. After a measurement time of approx. 1,000 seconds, a potential of approx. −0.6 V sets in. This potential also lies significantly below the steel potential. After a measurement time of approx. 3,500 seconds, this part of the coating is depleted and the required potential for dissolution of the coating approaches the steel potential. After the annealing, this coating consequently provides a cathodic corrosion protection in addition to the barrier protection. Up to a measurement time of 3,500 seconds, the potential has a value of ≦−0.6 V so that an appreciable cathodic protection is maintained over a long time period, even if the sheet has been brought to austenitization temperature. FIG. 7 shows the potential/time graph.
EXAMPLE 4 (ACCORDING TO THE INVENTION)
[0079] The sheet is conveyed through a heat melting bath or zinc bath with a zinc content of 99.8% and an aluminum content of 0.2%. During the annealing, aluminum contained in the zinc coating reacts to atmospheric oxygen and forms a protective Al 2 O 3 skin. Continuous diffusion of the high oxygen affinity aluminum to the surface causes this protective skin to form and keeps it maintained. After annealing, the sheet has a silver-gray surface without defects. During annealing, diffusion transforms the zinc coating that was originally approx. 15 μm thick into a coating approx. 20 to 25 μm thick; this coating ( FIG. 8 ) is composed of a dark-looking phase with a Zn/Fe composition of approx. 30/70 and a light region with a Zn/Fe composition of approx. 80/20. The surface of the coating has been verified to have an increased aluminum content. The detection of oxides on the surface indicates the presence of a thin protective coating of Al 2 O 3 .
[0080] At the beginning of the galvanostatic dissolution, the annealed material has a potential of approx. −0.75 V. After a measurement time of approx. 1,500 seconds, the potential required for dissolution rises to ≦−0.6 V. The phase lasts until a measurement time of approx. 2,800 seconds. Then, the required potential rises to the steel potential. In this case, too, a cathodic corrosion protection is provided in addition to the barrier protection. Up to a measurement time of 2,800 seconds, the potential has a value of ≦−0.6 V. A material of this kind consequently also provides a cathodic protection over a very long time period. FIG. 9 shows the potential/time graph.
EXAMPLE 5 (NOT ACCORDING TO THE INVENTION)
[0081] After the sheet band emerges from the zinc bath (approx. 450° C. band temperature), the sheet is heated to a temperature of approx. 500° C. This causes the zinc layer to completely convert into Zn—Fe phases. The zinc layer is thus completely converted into Zn—Fe phases, i.e. all the way to the surface. This yields zinc-rich phases on the steel sheet that all have a Zn to Fe ratio of >70% zinc. In this corrosion protection coating, the zinc bath contains a small amount of aluminum, on the order of magnitude of approx. 0.13%.
[0082] A 1 mm-thick steel sheet with the above-mentioned heat-treated and completely converted coating is heated for 4 minutes 30 seconds in a 900° C. furnace. This yields a yellow-green surface.
[0083] The yellow-green surface indicates an oxidation of the Zn—Fe phases during the annealing. No presence of an aluminum oxide protective layer could be verified. The reason for the absence of an aluminum oxide layer can be explained by the fact that during the annealing treatment, the presence of the solid Zn—Fe phases prevents the aluminum from migrating to the surface as rapidly and protecting the Zn—Fe coating from oxidation. When this material is heated, at temperatures around 500° C., there is not yet any fluid zinc-rich phase because this only forms at higher temperatures of 782° C. Once 782° C. is reached, a thermodynamically generated fluid, zinc-rich phase is present, in which the aluminum is freely available. The surface layer, however, is not protected from oxidation.
[0084] At this point in time, it is possible that the corrosion protection coating is already partially oxidized and it is no longer possible for a full-coverage aluminum oxide skin to form. The coating in the transverse section appears rough and wavy and is comprised of Zn oxides and Zn—Fe oxides ( FIG. 11 ). In addition, due to the highly crystalline, acicular surface structure of the surface, the surface area of the above-mentioned material is much greater, which could also be disadvantageous for the formation of a full-coverage, thicker aluminum oxide protection coating. In the initial state, i.e. when it has not yet been heat treated, the above-mentioned coating not according to the invention constitutes a brittle coating with numerous fractures oriented both transversely and longitudinally in relation to the coating. ( FIG. 10 , compared to the previously mentioned example according to the invention (on the left in the figure).) As a result, in the course of the heating, both a decarburization and an oxidation of the steel substrate can occur, particularly in cold formed parts.
[0085] In the galvanostatic dissolution of this material, for the dissolution with a constant current flow, at the beginning of the measurement, a potential of +1V is applied, which then levels off to a value of approx. +0.7V. Here, too, the potential during the entire dissolution lies significantly below the steel potential ( FIG. 12 ). These annealing conditions thus also indicate a pure barrier protection. Here, too, no cathodic corrosion protection could be verified.
EXAMPLE 6 (ACCORDING TO THE INVENTION)
[0086] As in the example mentioned above, immediately after the hot-dip galvanization, a sheet undergoes a heat treatment at approx. 490° C. to 550° C., which only partially converts the zinc layer into Zn—Fe phases. The process here is carried out so that only part of the phase conversion occurs so that as yet unconverted zinc with aluminum is present at the surface and consequently, the free aluminum is available as an oxidation protection for the zinc coating.
[0087] A 1 mm-thick steel sheet with the heat-treated coating that is only partially converted into Zn—Fe phases according to the invention is inductively heated rapidly to 900° C. This yields a gray surface without defects. An REM/EDX test of the transverse section ( FIG. 13 ) shows a surface layer approx. 20 μm thick; the originally approx. 15 μm-thick zinc covering on the coating has, during the inductive annealing, transformed due to the diffusion into an approx. 20 μm Zn—Fe coating; this coating has the two-phase structure that is typical of the invention, having a “leopard pattern” with a phase that looks dark in the image and contains a Zn/Fe composition of approx. 30/70 and light regions with a Zn/Fe composition of approx. 80/20. Moreover, certain individual areas have zinc contents of ≧90%. The surface turns out to have a protective coating of aluminum oxide.
[0088] In the galvanostatic dissolution of the surface coating, a rapidly heated sheet bar with the hot-dip galvanized coating according to the invention, which is—by contrast with example 5—only partially heat treated before the press hardening, at the beginning of the measurement, the potential required for dissolution is approx. −0.94 V and is therefore comparable to the potential required for dissolution of an unannealed zinc coating. After a measurement time of approx. 500 seconds, the potential rises to a value of −0.79 V and thus lies significantly below the steel potential. After a measurement time of approx. 2,200 seconds, ≦0.6 V are required for dissolution; the potential then rises to −0.38 V and then approaches the steel potential ( FIG. 14 ). The rapidly heated material, which has been incompletely heat-treated according to the invention before the press hardening, can provide both a barrier protection and a very good cathodic corrosion protection. In this material, too, the cathodic corrosion protection can be maintained for a very long measurement time.
EXAMPLE 7 (NOT ACCORDING TO THE INVENTION)
[0089] A sheet is electrolytically galvanized by electrochemical depositing of zinc onto steel. During the annealing, the diffusion of the steel with the zinc coating forms a thin Zn—Fe layer. Most of the zinc oxidizes into zinc oxide, which has a green appearance due to the simultaneous formation of iron oxides. The surface has a green appearance with localized scaly areas in which the zinc oxide layer does not adhere to the steel.
[0090] An REM/EDX test ( FIG. 15 ) of the sample sheet confirms, in the transverse section, that a majority of the coating is comprised of a covering of zinc-iron oxide. In the galvanostatic dissolution, the potential required for the current flow is approx. +1V and thus lies significantly above the steel potential. In the course of the measurement, the potential fluctuates between +0.8 and −0.1 V, but lies above the steel potential during the entire dissolution of the coating. It follows, therefore, that the corrosion protection of an annealed, electrolytically galvanized coating is a pure barrier protection, but is less efficient than in a hot-dip aluminized sheet since the potential at the beginning of the measurement is lower in an electrolytically coated sheet than it is in a hot-dip aluminized sheet. The potential required for dissolution lies above the steel potential during the entire dissolution. Consequently even an annealed, electrolytically coated sheet does not provide a cathodic corrosion protection at any time. FIG. 16 shows the potential/time graph. The potential lies essentially above the steel potential, but fluctuates in detail from one test to another, despite identical test conditions.
EXAMPLE 8 (NOT ACCORDING TO THE INVENTION)
[0091] A sheet is produced by means of electrochemical depositing of zinc and nickel onto a steel surface. The weight ratio of zinc to nickel in the corrosion protection coating is approx. 90/10. The deposited layer thickness is approx. 5 μm.
[0092] The sheet with the coating is annealed in the presence of atmospheric oxygen for 4 minutes 30 seconds at 900° C. During the annealing, the diffusion of the steel with the zinc coating produces a thin diffusion layer comprised of zinc, nickel, and iron. Due to the lack of aluminum, though, most of the zinc oxidizes into zinc oxide. The surface has a scaly, green appearance with small, localized spalling areas where the oxide coating does not adhere to the steel.
[0093] An REM/EDX test of a transverse section ( FIG. 17 ) demonstrates that most of the coating has oxidized and is consequently unavailable for cathodic corrosion protection.
[0094] At the beginning of the measurement, at 1.5 V, the potential required for dissolution of the coating lies far above the steel potential. After approximately 250 seconds, it falls to approx. 0.04 V and oscillates within a range of ±0.25 V. After approx. 1,700 seconds of measurement time, it levels off to a value of −0.27 V and remains at this value until the end of the measurement. The potential required for dissolution of the coating lies significantly above the steel potential for the entire measurement time. Consequently, after the annealing, this coating performs a pure barrier function without any cathodic corrosion protection whatsoever ( FIG. 18 ).
9. Verification of the Aluminum Oxide Layer by Means of GDOES Analysis
[0095] A GDOES (Glow Discharge Optical Emission Spectroscopy) test can be used to verify the formation of the aluminum oxide layer during the annealing (and the migration of the aluminum to the surface).
[0096] For the GDOES measurement:
[0097] A 1 mm-thick steel sheet coated according to example 4, with a coating thickness of 15 μm was heated in air for 4 min 30 s in a 900° C. radiation furnace, then rapidly cooled between 5 cm-thick steel plates, and then the surface was analyzed with a GDOES measurement.
[0098] FIGS. 25 and 26 show GDOES analyses of the sheet coated according to example 4, before and after the annealing. Before the hardening ( FIG. 25 ) after approx. 15 μm, the transition from the zinc coating to the steel is reached; after the hardening, the coating is approx. 23 μm thick.
[0099] After the hardening ( FIG. 26 ), the increased aluminum content at the surface is evident in comparison to the unannealed sheet.
10. CONCLUSION
[0100] The examples demonstrate that only the corrosion protected sheets used according to the invention for the press hardening process have a cathodic corrosion protection after the annealing, in particular with a cathodic corrosion protection energy of >4 J/cm 2 . FIG. 19 shows a comparison of the potentials required for dissolution as a function of time.
[0101] In order to properly evaluate the quality of the cathodic corrosion protection, it is not permissible to only examine the length of time for which the cathodic corrosion protection can be maintained; it is also necessary to take into account the difference between the potential required for the dissolution and the steel potential. The greater this difference is, the more effective the cathodic corrosion protection, even with poorly conductive electrolytes. The cathodic corrosion protection is negligibly low in poorly conductive electrolytes when there is a voltage difference of 100 mV from the steel potential. Even with a small difference from the steel potential, however, a cathodic corrosion protection is still present in principal as long as a current flow is detected when a steel electrode is used; this is, however, negligibly low for practical aspects since the corrosive medium must be very conductive for this to contribute to the cathodic corrosion protection. This is practically never the case with atmospheric influences (rainwater, humidity, etc.). For this reason, the evaluation did not take into account the difference between the potential required for dissolution and the steel potential, but instead used a threshold of 100 mV below the steel potential. Only the difference up to this threshold was taken into account for the evaluation of the cathodic protection.
[0102] The area between the potential curve during the galvanostatic dissolution and the established threshold of 100 mV below the steel potential was established as an evaluation criterion for the cathodic protection of the respective surface coating after annealing ( FIG. 20 ). Only the area that lies below the threshold is taken into account. The area above the threshold is negligibly small and makes practically no contribution whatsoever to the cathodic corrosion protection and is therefore not included in the evaluation.
[0103] The area thus obtained, when multiplied by the current density, corresponds to the protection energy per unit area with which the base material can be actively protected from corrosion. The greater this energy is, the better the cathodic corrosion protection. FIG. 21 compares the determined protection energies per unit area to one another. While a sheet with the aluminum-zinc coating comprised of 55% aluminum and 44% zinc that is known from the prior art only has a protection energy per unit area of approx. 1.8 J/cm 2 , the protection energies per unit area of sheets coated according to the invention are 5.6 J/cm 2 and 5.9 J/cm 2 .
[0104] For the cathodic corrosion protection according to the present invention, it is determined below that 15 μm-thick coatings and the above-described processing and testing conditions yield a cathodic corrosion protection energy of at least 4 J/cm 2 .
[0105] A zinc coating that has been electrolytically deposited onto the surface of the steel sheet cannot by itself provide a corrosion protection according to the invention, even after a heating step that brings it to a temperature higher than the austenitization temperature. However, the present invention can also be achieved with an electrolytically deposited coating according to the invention. To accomplish this, the zinc, together with the high oxygen affinity element(s) can be simultaneously deposited in an electrolysis step onto the surface of the sheet so that the surface of the sheet is provided with a coating of a homogeneous structure that contains both zinc and the high oxygen affinity element(s). When heated to the austenitization temperature, a coating of this kind behaves in the same manner as a coating of the same composition that is deposited on the surface of the sheet by means of hot-dip galvanization.
[0106] In another advantageous embodiment form, only zinc is deposited onto the surface of the sheet in a first electrolysis step and the high oxygen affinity element(s) is/are deposited onto the zinc layer in a second electrolysis step. The second layer comprised of the high oxygen affinity elements here can be significantly thinner than the zinc layer. When such a coating according to the invention is heated, the outer covering—which is composed of the high oxygen affinity element(s) and is situated on the zinc layer—oxidizes, thus protecting the underlying zinc with an oxide skin. Naturally, the high oxygen affinity element(s) is/are selected so that they do not vaporize from the zinc layer or do not oxidize without leaving behind a protective oxide skin.
[0107] In another advantageous embodiment form, first a zinc layer is electrolytically deposited and then a layer of the high oxygen affinity element(s) is deposited by means of vaporization or other suitable non-electrolytic coating processes.
[0108] It is typical of the coatings according to the invention that in addition to the surface protective layer comprised of an oxide of the high oxygen affinity element(s), in particular Al 2 O 3 , after the heat treatment for the press hardening, the transverse sections of the coatings according to the invention have a typical “leopard pattern” that is composed of a zinc-rich, intermetallic Zn—Al phase and an iron-rich Fe—Zn—Al phase, the iron-rich phase having a ratio of zinc to iron of at most 0.95 (Zn/Fe≦0.95), preferably from 0.20 to 0.80 (Zn/Fe=0.20 to 0.80), and the zinc-rich phase having a ratio of zinc to iron of at least 2.0 (Zn/Fe≧2.0), preferably from 2.3 to 19.0 (Zn/Fe=2.3 to 19.0). It was possible to verify that only when such a two-phase structure is achieved is there a sufficient amount of cathodic protective action. Such a two-phase structure is only produced, however, if the Al 2 O 3 has already formed on the surface of the coating. By contrast with a known coating according to U.S. Pat. No. 6,564,604 B2, which has a homogeneous makeup in terms of structure and texture in which the Zn—Fe needles are supposed to lie in a zinc matrix, in this case, a non-homogeneous structure is composed of at least two different phases.
[0109] The invention is advantageous in that a continuous and therefore economically produced steel sheet is achieved for the manufacture of press-hardened parts and has a cathodic corrosion protection that is reliably maintained even when the sheet is heated above the austenitization temperature and subsequently formed. | The invention relates to a method for producing a hardened steel part having a cathodic corrosion protection, whereby a) a coating is applied to a sheet made of a hardenable steel alloy in a continuous coating process; b) the coating is essentially comprised of zinc; c) the coating additionally contains one or more oxygen-affine elements in a total amount of 0.1% by weight to 15% by weight with regard to the entire coating; d) the coated steel sheet is then, at least in partial areas and with the admission of atmospheric oxygen, brought to a temperature necessary for hardening and is heated until it undergoes a microstructural change necessary for hardening, whereby; e) a superficial skin is formed on the coating from an oxide of the oxygen-affine element(s), and; f) the sheet is shaped before or after heating, and; g) the sheet is cooled after sufficient heating, whereby the cooling rate is calculated in order to achieve a hardening of the sheet alloy. The invention also relates to a corrosion protection layer for the hardened steel part and to the steel part itself. | 54,860 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional Application, Ser. No. 60/178,348, filed Jan. 25, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to electronic gaming apparatus and methods and, more particularly, to such apparatus and methods for playing games such as poker, slot machines, keno, and secondary feature games. More specifically, the present invention relates to electronic gaming machines and methods that provide one or more players with the option to play individual games independently or simultaneously or, where there are multiple machines, to play such games independently or simultaneously and jointly with one or more players seated at separate machines.
[0004] 2. Description of the Prior Art
[0005] Electronic video gaming machines, for example, the GAME KING® by IGT® and the GAME MAKER® of Bally Gaming Systems®, have become a significant part of the gaming industry. With the help of advancements in microcomputer technology manufactures have expanded game features to allow players the ability to play a variety of games e.g., Slot, Poker, Keno, etc., to be displayed in a single game format (one game per machine) or a multi-game format (a variety of games per machine). Depending upon the machine, a player has the option of playing an independent game from a single game format or the ability to play an independent game from a multi game format. These advanced features are used to increase player appeal and to increase the volume of play (“coin-in”). The proliferation of legalized gaming has saturated the desirable locations for gaming establishments. Manufacturers of electronic video machines have been creating new games, bonuses, and a variety of progressive systems having giant jackpots—all to attract players and raise the volume of “coin in” in efforts, which helps casinos maximize profits over their limited gaming floor space. Casinos also compete for “player time” with other casinos because of the normal close proximity of the establishments.
[0006] Today game manufacturers are using a number of strategies to sell new machines, create player appeal, promote play and most importantly, increase the volume of coin in. A few of these strategies are listed below:
[0007] 1. Using current technology, gaming companies are improving old games and creating new games with sophisticated hardware, software, and video graphics;
[0008] 2. Using U.S. Pat. No. 4,448,419, permits an electronic gaming machine to have higher odds. Manufacturers & Casinos are using wide area progressive systems that can link together electronic gaming machines from casino to casino, forming one progressive jackpot. The more machine connected to a single progressive the faster it will grow. Wide area progressive systems create fast, growing progressives that are seeded with high jackpot amounts;
[0009] 3. Using entertaining themes, gaming companies are using the familiarity of TV shows, board games and personalities to create entertaining new games; and
[0010] 4. Using second event games, as in U.S. Pat. No. 5,823,874, gaming companies are creating special payouts and bonuses.
[0011] All of the strategies listed above have proven successful in the gaming market. However, even with the use of current technology and ingenious gaming concepts, up until the present day the player has only been able to play one independent game at a time. By using the proper programming, the method of the present invention can be used with all the strategies listed above.
[0012] Presently, the only way for a player to play multiple games is to concurrently play on adjoining machines. There has also been a limit to the justified odds and pay tables constructed from the existing games.
SUMMARY OF THE INVENTION
[0013] There is a demand in the gaming market for a new method of game play on electronic video machines. A method of game play that would provide the player with: new games and/or bonuses with higher odds and larger jackpots, that would not change the percentage of payback on existing games; a method of game play that would allow for a higher volume of “coin-in” per machine; and a method of game play that would promote groups of game players to participate in the same establishment.
[0014] By programming electronic video machines to permit players to play independent games or to play such independent games simultaneously and/or in conjunction with other independent games. Pay tables with higher odds and larger jackpots could be created for such new games and/or bonuses. This strategy would also allow for a higher volume of “coin in” by allowing the player(s) to place multiple wagers on multiple games using a independent electronic video machine or networked independent electronic video machine. This method would create a new dimension of game play for players and the gaming industry.
[0015] The method of the present invention can be used on any electronic gaming apparatus and more particularly to that class of gaming machines known as “electronic video machines” that are suitably programmed. Furthermore, where such a machine is so programmed, the method of the present invention can be used with virtually all of the existing games and game styles (Slot, Poker, Keno, etc.), as are available in the gaming market today.
[0016] The growth in new casinos is slowing, and new machine replacement is expected to drive the bulk of future business in the gaming market. This in turn provides a great opportunity to upgrade older machines and create a new generation of gaming machines with a method of game play that will enable casinos to have a higher volume of “coin in”.
[0017] It is an object of the present invention to be used in any old or new gaming apparatus that is suitably programmed in the gaming market.
[0018] It is a still further object of the present invention to provide a method of game play on a gaming machine that gives the player a more entertaining gaming experience, and one that is easy to understand.
[0019] The method of the present invention is also beneficial to the casinos and the customers. By enabling the player to play independent games simultaneously and/or in conjunction with other games, the player can play more than one of his or her favorite games at the same time without having to move from one machine to the next. This can be accomplished in an auto-play style and/or the player can play all the independent games on the screen at the same time.
[0020] With casinos and other gaming establishments having limited floor space, even when all of the gaming machines are being played, there remains a limit to the amount of “coin in” possible using those machines and their present manner of play. In contrast, utilization of the present inventive method enables an increase in the “coin in”, generating more revenue for the casino and giving the player a new entertaining gaming experience.
[0021] It is a further object of the present invention to provide a method of game play on an electronic gaming machine that allows for a higher volume of “coin in”, while also permitting the player to play the same games to which they have become accustomed.
[0022] The method of the present invention permits a player to wager on and play independent games (for example, those having different odds and pay tables) independently, simultaneously, and/or in conjunction with the same machine game from another electronic gaming machine over a game machine network.
[0023] Accordingly, the method of the present invention permits a player to choose the combination of independent games, i.e., those having different odds and pay tables, game styles, denominations, and wagers, yet play such games independently, simultaneously, and/or in conjunction with the other same machine games from an electronic gaming machine.
[0024] Yet another object of the present invention is to provide the player(s) with new games and additional opportunities to receive winning payouts.
[0025] It is a still further object of the present invention to provide a method of game play on an electronic gaming machine that allows for higher odds by creating, based upon a player's selection of games, pay tables for new games and/or bonuses. These newly created or create-able pay tables will in turn provide players the opportunity to play for higher jackpots and bonuses.
[0026] The method of the present invention is to permit the player(s) to wager on and play independent games independently, simultaneously, and/or in conjunction with other games from one or more electronic gaming machines. In addition, if the player(s) chooses to play more than one independent game at a time, the present invention allows the player(s) to become eligible for new games and/or bonuses. The independent games e.g. odds and pay tables, and wagers selected by the player then become parameters in pay tables created from the predetermined indicia of the independent games to create new games and/or bonuses.
[0027] A method of the present invention permits the player(s) to choose the combination of independent games, for example, the same or different odds and pay tables, game styles, denominations, and wagers, to be played simultaneously and/or in conjunction with other independent games—those of different odds and pay tables, game styles, denominations, and wagers on more than one electronic gaming machine. The independent games and wagers selected by the player(s) then become parameters in pay tables created from the predetermined indicia of the independent games to create new games and/or bonuses. Utilizing this method of game play, the player is allowed to play his or her favorite independent games while playing a new game and/or bonus.
[0028] In a still further object of the present invention, through utilization of a networked gaming system, and by identifying groups of gaming machines with numbers, letters, etc. (for example, machine 1,2,3; machine A,B,C; and so forth), on the video screen of the gaming machines, groups of electronic gaming machines can be linked together, permitting player(s) from the selected groups of gaming machines to play with other player(s) on the same group of gaming machines, using the same method of game play as is described above.
[0029] By adding a feature on the video screen that identifies the machines in the group, a player on machine one could select to play with a player on machine two, or with any other player(s) that want to participate in a new game and/or bonus that are playing at the time on the identified group of machines. Likewise, a player on machine two could select to play with a player on gaming machine one, or any other players that want to participate in the new game and/or bonus that are playing at the time on the identified group of machines.
[0030] In this manner players would be able to play as groups or teams for the same new games and/or bonuses that are described above. The independent games and wagers selected by the player(s) then become parameters in pay tables created from the predetermined indicia of the independent games to create new games and/or bonuses.
[0031] The method of game play under the present invention permits new games and/or bonuses to be created with higher odds and higher paybacks for the player(s) that can be used for large jackpots and/or in conjunction with networked gaming systems, progressive and wide-area progressive, and internet gaming systems. The variety of game pay tables that can be used to create new game and/or bonuses for the player is limited only to the programmer and the options programmed into the chosen gaming apparatus.
[0032] It is still another important object of the method of the present invention to permit a player(s) to choose the combination of independent progressive and non-progressive games, game styles, denominations, and wagers to be played independently, simultaneously, and/or in conjunction with other independent progressive and non-progressive games, game styles, denominations, wagers on one or more electronic gaming machine at any remote or multiple-remote gaming and non-gaming sites, using any remote or compatible wide-area progressive systems.
[0033] The games, and wagers selected by the player then become parameters in pay tables created from the predetermined indicia of the independent progressive and non-progressive games to create new games and bonuses. In this manner, the player is allowed to play his or her favorite independent games while playing for a progressive or wide-area progressive jackpots.
[0034] It is still another important object of the method of the present invention to permit the player(s) to choose the combination of independent progressive and non-progressive games, for example, different odds and pay tables, game styles, denominations, and wagers, to be played simultaneously and/or in conjunction with other independent progressive and non-progressive games, i.e., different odds and pay tables, game styles, denominations, and wagers on more that one electronic gaming apparatus. The games and wagers selected by the player then become parameters in pay tables created from the predetermined indicia of the independent progressive and non-progressive games to create new progressive and wide-area progressive games. This is made possible under the present invention by permitting play on one or more independent gaming machine that is simultaneous and/or in conjunction with machine games. It is thus possible to combine the odds of the independent games to create “combination” games having higher odds.
[0035] The method of the present invention is made possible by using a multi-tasking platform in an electronic gaming machine that is properly programmed. In order for players from different electronic gaming apparatuses to play together for the same new games and/or bonuses, the electronic gaming machine must be networked on any suitable gaming system that is being used in the market today.
[0036] While the method of the present invention has been described by way of examples, it will be understood by those skilled in the art that it is not intended to limit the invention to these examples. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention. It is expected that some further objects, advantages, and features of the present invention shall become apparent from the ensuing description and as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0037] FIGS. 1 - 30 are schematic representations of different video display screens, of the type as might be shown on gaming machines in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0038] The method of the present invention is to permit the player the option to play an independent game in a single game format independently, simultaneously, and/or in conjunction with other independent games. FIGS. 1 - 4 are basic illustrations displaying information and showing one example of how a player would play an independent game independently and FIGS. 5 - 12 show one example of how a player would play an independent game simultaneously and/or in conjunction with other independent games utilizing the method of game play of the present invention on a video touch screen gaming machine in a single game format.
[0039] The method of the present invention is also intended to permit the player to choose the combination of independent games e.g. different odds and pay tables, game styles, e.g., poker, keno, slot, bingo, blackjack, and the like, for a variety of monetary denominations, (5 cents, 25 cents, one dollar, etc.) and a variety monetary wagers, (1 coin, 2 coins, max bet, etc.). Permitting, in a multi game, denomination, and wager format, play of the games independently, simultaneously and/or in conjunction with other independent games.
[0040] [0040]FIG. 28 is a basic display illustration of three independent poker games after the player has selected the games, denominations, and wagers from an electronic video touch screen gaming machine menu. The same method of game play is applied here as in FIGS. 1 - 11 , only now in a multi-game, denomination, and wager format.
[0041] Using this method of game play, there is an unlimited number of independent game e.g. odds and pay tables, denomination, and wager combinations that can be played simultaneously and/or in conjunction with other independent games e.g. odds and pay tables, denominations, and wagers. This inventive technology thus creates new entertaining game play for the player while also allowing a higher volume of coin in for the casinos, with the player now allowed to wager on more than one game.
[0042] The method of the present invention is also intended to permit the player(s) to play an independent game in a single game format independently, simultaneously, and/or in conjunction with independent games from one or more electronic gaming machines. Should the player(s) choose to play more than one independent game at a time, the independent games (i.e. odds and pay tables), and wagers selected by the player(s) then become parameters in pay tables created from the predetermined indicia of the independent games to create New Games and/or New Bonuses.
[0043] FIGS. 13 - 19 are basic illustrations showing how a player(s) would become eligible for bonus pays, created by utilizing the method of game play on a video touch screen gaming machine in a single game format. FIGS. 21 - 26 are basic illustrations of how a player(s) would play a new game, to be referred hereinafter as BIG MONEY, created by utilizing the method of game play on a video touch screen gaming machine in a multi game format.
[0044] The method of the present invention is also intended to permit a player(s) to choose a combination of independent games game styles from one or more gaming apparatuses, as well as denominations and wagers in a multi-game format to be played simultaneously and/or in conjunction with other independent games e.g. different odds and pay tables, game styles, denominations, and wagers. The games e.g. different odds and pay tables and wagers selected by the player(s) then become parameters in pay tables created from the predetermined indicia of the independent games to thereby create New Games and/or New Bonuses.
[0045] [0045]FIG. 29 is a basic illustration displaying information and two independent poker games with Bonus Pays after the player(S) has selected the games, denominations, and wagers from a menu on an electronic video touch screen gaming machine. The same method of game play is applied here as in FIGS. 13 - 19 , only now in a multi-game, denomination, and wager format. FIG. 30 is a basic illustration displaying information and two independent poker games and the BIG MONEY after the player(s) has selected the games, denominations, and wagers from a menu located on an electronic video touch screen gaming machine. The same method of game play is applied here as in FIGS. 21 - 27 , only now in a multi-game, denomination, and wager format.
[0046] A multi-game offers a player a set of games, {G1, G2, . . . , Gn} that may be played simultaneously. Each game, Gi, has an associated set of outcomes, {O1, O2, . . . Om} that occur with probabilities {p1, p2, . . . , pm}. This preferred embodiment describes a bonus method based on combinations of outcomes of simultaneous games. Each game is played with independent wagers that may or may not be identical.
[0047] Total bonuses equal the sum of amounts bonused for each possible combination of outcomes times the probability of occurrence of the combination of outcomes. Let pi, j equal the probability of occurrence of outcome Oj of game Gi. The subscript j may have a different range for each game as each game may have a different set of outcomes. The total expectation of bonuses, B, for n simultaneous games is therefore:
[0048] the sum of B(i,j) (k,l) (. . .)(n,m) times pi, jpk, lp . . . pn, m for each outcome, j, l, . . . , m of each game i, k, . . . , n played (where m may have a different value for each of n games).
[0049] For example, let game 1 have three possible outcomes, game 2 have four possible outcomes and game 3 have five possible outcomes with associated probabilities p1,1, p1,2, p1,3, p2,1, p2,2, p2,3, p2,4, p3,1, p3,2, p3,3, p3,4, p3,5. Then there are 3*4*5=60 possible bonus expectations:
[0050] B(1,1)(2,1)(3,1)p1,1p2,1p3,1
[0051] B(1,2)(2,1)(3,1)p1,2p2,1p3,1
[0052] B(1,3) (2,1) (3,1)p1,3p2,1p3,1
[0053] B(1,1) (2,2) (3,1)p1,1p2,2p3,1
[0054] B(1,2)(2,2)(3,1)p1,2p2,2p3,1
[0055] .
[0056] .
[0057] .
[0058] B(1,3)(2,4)(3,5)p1,3p2,4p3,5
[0059] The sum of these expectations divided by the wager required to win a bonus is the amount by which the game percentage is increased. Assume that it is desired that all expectations be equal. Then each bonus expectation should equal the total expectation divided by 60 since there are 60 possible combinations. Further assume a wager of one cent ($0.01) and a bonus payback of 1% (0.01). Then any bonus expectation is:
B (1,1) (2,1) (3,1) p 1,1 p 2,1 p 3,1=(0.01 * 0.01)/60
[0060] and the bonus amount to be paid on bonus combination of G1O1, G2O1, G3O1 is:
B (1,1)(2,1)(3,1)=(0.01*0.01)/60/( p 1,1 p 2,1 p 3,1)
[0061] From this point on, a simplified notation can be used to replace game numbers by position in a statement, i.e. B(1,1)(2,1)(3,1) and p1,1p2,1p3,1 become B111 and p1p2p3.
[0062] Continuing the example above let us arbitrarily assign values to outcome probabilities for each of the three games.
p Game 1 Outcome 1 0.9 Outcome 2 0.09 Outcome 3 0.01 Game 2 Outcome 1 0.8 Outcome 2 0.1 Outcome 3 0.07 Outcome 4 0.03 Game 3 Outcome 1 0.7 Outcome 2 0.2 Outcome 3 0.08 Outcome 4 0.012 Outcome 5 0.008
[0063] Then bonus values in dollars (per penny wagered per percent of payback) equal:
B 111=(0.01*0.01)/60/(0.9*0.8*0.7)=$0.000003306
B 211=(0.01*0.01)/60/(0.09*0.8*0.7)=$0.00003306
B 311=(0.01*0.01)/60/(0.01*0.8*0.7)=$0.0002976
B 121=(0.01*0.01)/60/(0.9*0.1*0.7)=$0.000026455
B 221=(0.01*0.01)/60/(0.09*0.1*0.7)=$0.00026455
B 321=(0.01*0.01)/60/(0.01*0.1*0.7)=$0.002380952
B 131 (0.01*0.01)/60/(0.9*0.07*0.7)=$0.000037792
.
.
.
B 335=(0.01*0.01)/60/(0.01*0.07*0.008)=$0. 297619047
B 145 (0.01*0.01)/60/(0.9*0.03*0.008)=$0. 007716049
B 245=(0.01*0.01)/60/(0.09*0.03*0.008)=$0. 077160493
B 345=(0.01*0.01)/60/(0.01*0.03*0.008)=$0.694444444
[0064] The maximum bonus in this example is B345 and is equal to 69.444 times wager.
[0065] As a specific example let us consider three games of stud poker played simultaneously. For each game there are ten possible outcomes with probabilities:
No pair 0.501177394 One pair 0.422569027 Two pairs 0.047539015 Three of a kind 0.021128451 Straight 0.003924646 Flush 0.001965401 Full house 0.001440576 Four of a kind 0.000240096 Straight flush 0.000013851 Royal flush 0.000001539
[0066] There are 1000 possible bonus combinations which gives bonus values equal to:
[ Bxyz =(0.01*0.01)/1000/( px*py*pz )]
B 1 1 1=0.0000001/(0.501177394*0.501177394*0.501177394)=$0.000000794
B 2 1 1=0.0000001/(0.422569027*0.501177394*0.501177394)=$0.000000942
B3 1 1=0.0000001/(0.047539015*0.501177394*0.501177394)=$0.000008374
B 4 1 1=0.0000001/(0.021128451*0.501177394*0.501177394)=$0.000018842
.
B 1 5 7=0.0000001/(0.501177394*0.003924646*0.001440576)=$0.035291641
B 2 5 7=0.0000001/(0.422569027*0.003924646*0.001440576)=$0.041856766
B 3 5 7=0.0000001/(0.047539015*0.003924646*0.001440576)=$0.372060149
B 4 5 7=0.0000001/(0.021128451*0.003924646*0.001440576)=$0.837135340
.
B 8 9 9=0.0000001/(0.000240096*0.000013851*0.000013851)=$2,170,964.97
B 9 9 9=0.0000001/(0.000013851*0.000013851*0.000013851)=$37,631,940.40
.
B 10 10 10=0.0000001/(0.000001539*0.000001539*0.000001539)=$27,433,684,550.00
[0067] This chart shows the awards to be paid a player who hits a given number of numbers on an 8-spot Keno ticket while simultaneously winning a given stud poker hand. Awards are for a 1% return for $1.00 bet.
No One Jacks or Three of Poker Hand Pair Pair Better Two Pair A Kind Straight KENO DOLLARS HIT 0 0 0 0 0 0 0 HIT 1 0 0 0 0 0 0 HIT 2 0 0 0 0 0 0 HIT 3 0 0 0 0 0 0 HIT 4 0 0 0 0 0 0 HIT 5 0 0 0 0 0 1 HIT 6 0 0 0 0 1 6 HIT 7 0 0 2 5 13 70 HIT 8 13 22 50 139 313 1686
[0068] [0068] Four of A Straight Poker Hand Flush Full House Kind Flush Royal Flush KENO DOLLARS HIT 1 0 0 1 27 245 HIT 2 0 0 1 23 210 HIT 3 0 0 2 35 316 HIT 4 0 0 4 84 758 HIT 5 2 3 18 316 2844 HIT 6 13 18 109 1896 17068 HIT 7 140 191 1148 19913 179223 HIT 8 3367 4594 27569 477891 4301021
[0069] The format in which a game can be programmed to permit a player to be able to play independent games simultaneously and/or in conjunction with other independent games is unlimited. The format that is described below is very basic in order not to stray from the spirit and scope of the invention.
[0070] In a flowing format, the manner of play of game machines utilizing the present invention is set forth as follows:
[0071] [0071]FIG. 1 shows a representation of a video touch screen displaying information and a conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits video poker game in a single game format. Giving the player the option to play one, two or three games: Player chooses \ one game.
[0072] [0072]FIG. 2 shows a representation of a video touch screen displaying information and a conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits video poker game in a single game format: Player selects play max credits, and deal.
[0073] [0073]FIG. 3 shows a representation of a video touch screen displaying information and a conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits video poker game in a single game format: Player receives five cards, holds two cards and selects draw.
[0074] [0074]FIG. 4 shows a representation of a video touch screen displaying information and a conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits video poker game in a single game format: Player receives 3 new cards; three of a kind winner paid 15 credits. Player selects play more games.
[0075] [0075]FIG. 5 shows a representation of a video touch screen displaying information and three independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits video poker game in a single game format: Player selects 3 games.
[0076] [0076]FIG. 6 shows a representation of a video touch screen displaying information and three independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits video poker game in a single game format: Player selects play max credits, and place bet game one.
[0077] [0077]FIG. 7 shows a representation of a video touch screen displaying information and three independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits video poker game in a single game format: Player selects play max credits, and place bet game two.
[0078] [0078]FIG. 8 shows a representation of a video touch screen displaying information and three independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits video poker game in a single game format: Player selects play max credits, and place bet game three.
[0079] [0079]FIG. 9 shows a representation of a video touch screen displaying information and three independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits video poker game in a single game format: Player selects deal.
[0080] [0080]FIG. 10 shows a representation of a video touch screen displaying three independent conventional Jacks or Better \ 25 cent \ Bet 1 to 5 credits video poker game pay tables.
[0081] [0081]FIG. 11 shows a representation of a video touch screen displaying information and three independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits video poker game in a single game format: Player receives five cards game one; Player receives five cards, holds two game two; Player receives five cards, holds two game three; and Player selected draw.
[0082] [0082]FIG. 12 shows a representation of a video touch screen displaying information and three independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits video poker game in a single game format: Player receives five new cards game one; Player receives three new cards, full house winner paid 45 credits game two; and Player receives three new cards; two pairs winner paid 10 credits game three.
[0083] [0083]FIG. 13 shows a representation of a video touch screen displaying information and a independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits with Bonus Pays video poker game in a single game format. Giving the player the option to play one, two or three games: Player selects two games.
[0084] [0084]FIG. 14 shows a representation of a video touch screen displaying information and a Bonus Pays video poker game pay table.
[0085] [0085]FIG. 15 shows a representation of a video touch screen displaying information and two independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits with Bonus Pays video poker game in a single game format: Player selects play max credits, and place bet game one.
[0086] [0086]FIG. 16 shows a representation of a video touch screen displaying information and two independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits with Bonus Pays video poker game in a single game format: Player selects play max credits, and place bet game two.
[0087] [0087]FIG. 17 shows a representation of a video touch screen displaying information and two independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits with Bonus Pays video poker game in a single game format: Player selects deal.
[0088] [0088]FIG. 18 shows a representation of a video touch screen displaying information and two independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits with Bonus Pays video poker game in a single game format: Player receives five cards, holds four cards game one; Player receives five cards, holds three cards game two; and Player selects draw.
[0089] [0089]FIG. 19 shows a representation of a video touch screen displaying information and two independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits with Bonus Pays video poker game in a single game format; Player receives one new cards, flush winner paid 30 credits game one; and Player receives two new cards, flush winner paid 30 credits game two; and Player receives two flushes Bonus Pays winner 20 credits.
[0090] [0090]FIG. 20 shows a representation of a video touch screen displaying draw poker hand frequencies created from the method of the present invention.
[0091] [0091]FIG. 21 shows a representation of a video touch screen displaying information and an independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits and Big Money video poker games in a multi game format: Player selects two games and BIG MONEY.
[0092] [0092]FIG. 22 shows a representation of a video touch screen displaying information and two independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits and Big Money video poker games in a multi game format: Player selects bet max credits and place bet game one.
[0093] [0093]FIG. 23 shows a representation of a video touch screen displaying information and two independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits and Big Money video poker games in a multi game format: Player selects bet max credits and place bet game two.
[0094] [0094]FIG. 24 shows a representation of a video touch screen displaying information and two independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits and Big Money video poker games in a multi game format: Player selects bet 5 credits and place bet Big Money; and Player selects deal.
[0095] [0095]FIG. 25 shows a representation of a video touch screen displaying information and two independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits and Big Money video poker games in a multi game format: Player receives five cards, holds two cards game one; Player receives five cards, holds two cards game two; and Player selects draw.
[0096] [0096]FIG. 26 shows a representation of a video touch screen displaying information and two independent conventional Jacks or Better \ 25 cent \ bet 1 to 5 credits and Big Money video poker games in a multi game format: Player receives three new cards, three-of-a-kind winner paid 15 credits game one; Player receives three new cards, three-of-a-kind winner paid 15 credits game two; and Player receives two three-of-a-kinds BIG MONEY winner paid 30 credits.
[0097] [0097]FIG. 27 shows a representation of a video touch screen displaying information and a Big Money video poker games pay table.
[0098] [0098]FIG. 28 shows a representation of a video touch screen displaying information and three independent video poker games in a multi game, denomination and wager format.
[0099] [0099]FIG. 29 shows a representation of a video touch screen displaying information and two independent video poker games with Bonus Pays in a multi game, denomination and wager format.
[0100] [0100]FIG. 30 a representation of a video touch screen displaying information and two independent video poker games and Big Money in a multi game, denomination and wager format.
[0101] Reference is now made to the drawings wherein like numerals refer to like features throughout.
[0102] In conventional video poker, an electronic gaming machine is programmed to display a five-card hand dealt from a standard deck of fifty-two playing cards. The player bets one to five coins and activates the “Deal” button (or receives the initial deal automatically if the maximum number of coins are bet) to receive the initial deal of five cards. After the initial deal of the cards, the player may hold any of the initially dealt cards and then the player may select the “Draw” button to receive replacement cards. The player receives a payout on the resulting hand if the player achieves one of the pre-designated poker hand combinations shown on the payout schedule. The player bases the amount of the payout on the number of coins bet.
[0103] To describe the method of the present invention, the same conventional video poker game play as is describe above will be used. As will be understood by people skilled in the art, in order for the method of the present invention to work, the electronic gaming machine must be suitably programmed to add these additional features.
[0104] FIGS. 1 - 4 are basic illustrations showing how a player would play an independent conventional video poker game on a video touch screen gaming machine in a single game format using the method described above. Under the present invention, however, the player has the option to choose between One Game, Two Games or Three Games (and as is conventionally the case, any action can be initialized by touching the screen).
[0105] [0105]FIG. 1 shows a representation of a video touch screen 10 displaying information and an independent conventional Jacks or Better \ 25 cent \ bet one to five credit video poker game, with (based on theoretical probabilities) a payback percentage of approximately 96%. Also shown is a typical payout schedule that is used in electronic video draw poker machines. In order to activate the gaming machine the player inserts money into the coin entry or bill validator (not shown). Player inserts $10.00 into bill validator (not shown), credit $10.00 (Ref Num 20 ). Player now has the option to select One Game, Two Games or Three Games 30 . In this example, Player selects One Game 40 .
[0106] In FIG. 2, Player selects play max credits 50 ; a bet of 5 credits is displayed 60 . To start play, Player selects Deal 70 . In FIG. 3, five cards are displayed, with Player holding the 2 of Hearts and the 2 of Spades in game one 80 . Player selects Draw 90 .
[0107] In FIG. 4, three new cards are displayed: the 2 of Clubs, the Ace of Diamonds and the Queen of Spades (game one 80 ). Player receives three of a kind, and Player wins 15 credits 110 (credit $11.25 120 ). Player selects play more games 125 .
[0108] [0108]FIG. 5- 11 are basic illustrations displaying information and showing how a player would play an independent game simultaneously and/or in conjunction with other independent games using the method of the present invention on a video touch screen gaming machine in a single game format.
[0109] [0109]FIG. 5, is a representation of a video touch screen displaying information—independent conventional Jacks or Better \ Bonus Pays \ 25 cent \ bet one to five coin video poker game, with the option to play one, two or three games.
[0110] In order to activate the gaming machine the player inserts money into the coin entry or bill validator (not shown). In this example, Player inserts a $10.00 into bill validator (not shown)—credit $10.00 200 . Player selects Three games.
[0111] [0111]FIG. 6 is a representation of a video touch screen displaying information and three independent conventional Jacks or Better \ 25 cent \ bet one to five credit video poker games—Game one 130 , Game two 140 , and Game three 150 . Player selects play max credits 50 and places bet game one 160 . In FIG. 7 Player selects play max credits 50 then selects place bet game two 170 . In FIG. 8, Player selects play max credits 50 then selects place bet game three 180 .
[0112] In FIG. 9, a representation of a video touch screen displaying information, requiring three independent Jacks or better \ 25 cent video \ Bet 1 to 5 credit poker games, before the player activates game play. Player bets five credits game one 130 , bets five credits game two 140 , and bets five credits game three 150 (credit $6.25 190 ).
[0113] [0113]FIG. 10 is a representation of the three independent 25 cent \ Jacks or better \ bet one to five credits pay tables for game one, two, and three.
[0114] In FIG. 9, Player selects Deal 70 . FIG. 11 is a representation of a video touch screen displaying information and five cards displayed game one 130 . Five cards displayed, player holds King of Spades and King of Diamonds game two 140 . Five cards displayed, player holds Two of Hearts and Two of Spades game three 150 . Player selects Draw 90 .
[0115] In FIG. 12 five new cards are displayed game one 130 , in game two three new cards are displayed 2 of Spades, 2 of Diamonds and the 2 of Clubs. Player receives a full house, winner is paid 45 credits on game two 140 , and in game three, three new cards are displayed 8 of Clubs, 8 of Hearts and the 3 of Clubs. Player receives two pairs, and winner is paid 10 credits on game three 150 (credit $22.00 190 ).
[0116] FIGS. 13 - 19 are basic illustrations showing how a player would become eligible for bonus pays, using the method of the present invention on a video touch screen gaming machine in a single game format.
[0117] [0117]FIG. 13 is a representation of a video touch screen displaying information—independent conventional Jacks or Better \ Bonus Pays \ 25 cent \ bet one to five coin video poker game, with the option to play one, two or three games.
[0118] In order to activate the gaming machine the player inserts money into the coin entry or bill validator (not shown). In this example, Player inserts a $10.00 into bill validator (not shown)—credit $10.00 200 . This is the same video poker game illustrated in FIG. 1, only now the player can become eligible for bonus pays by playing max coins on two or more games 210 . FIG. 13 Player selects two games 220 (see bonus pays 230 , FIG. 14 as an example of a bonus pays pay table). Player is eligible for bonus pays while playing max coins on two or more games. Player wins if he or she receives two or more Royal Flushes, Straight Flushes, Four of a kinds, Full Houses, Flushes, Straights, Three of a Kinds, Two Pairs, or Jacks or Better.
[0119] If the Player chooses to play more than one independent game at a time, the independent games selected by the player then become parameters in pay tables created from the predetermined indicia, for example, Royal Flush, Four of a kind, etc., of the independent games to create bonus pays.
[0120] In FIG. 15, Player selects: play max credits 50 , and places this bet game one 130 . In FIG. 16, Player selects: play max credits 50 , in placing bet in game two 140 .
[0121] [0121]FIG. 17 is a representation of a video touch screen displaying information and two independent Jacks or better \ Bonus Pays \ 25 cent \ Bet 1 to 5 credits video poker games, before the player activates game play. As shown, the Player bets five credits in game one 130 , and bets five credits in game two 140 (credit $7.50 240 ). Player selects Deal 70 . In FIG. 18, five cards are displayed, Player holds 5, 3, 7, and 9 of Clubs game one 130 . Five cards are displayed, player holds Queen, 4, and 5 of Hearts game two 140 . Player selects Draw 90 .
[0122] In FIG. 19 one new card is displayed: Jack of Clubs, and Player receives a Flush—winner paid 30 credits on game one 130 . Two new cards are displayed 8 and 2 of Hearts, and Player receives a Flush—winner paid 30 credits on game two 140 . Player having received Two Flushes obtains a Bonus Pays—winner 20 credits 250 .
[0123] [0123]FIG. 20 is a representation of draw poker hand frequencies created from the method of the present invention. By allowing the player the option to play more than one game at a time, the interplay of the independent game hand frequencies creates combination game hand frequencies with extremely high odds that can be used for bonus pays and new games.
[0124] FIGS. 21 - 26 are basic illustrations of how a player would play a new game, to be referred hereinafter as BIG MONEY, created by utilizing the method of the present invention on a video touch screen gaming machine in a multi game format (see Big Money Pays 230 , with FIG. 27 an example of a Big Money pay table). Player is eligible for Big Money while playing two or more games and betting 5 credits on Big Money. Player wins if he or she receives two or more Royal Flushes, Straight Flushes, Four of a kinds, Full Houses, Flushes, Straights, Three of a Kinds, Two Pairs, or Jacks or Better.
[0125] If the Player chooses to play more than one independent game at a time, the independent games selected by the player then become parameters in pay tables created from the predetermined indicia, for example, Royal Flush, Four of a kind, etc., of the independent games to create Big Money.
[0126] [0126]FIG. 21 is a representation of a video touch screen displaying information and an independent conventional jacks or Better \ 25 cent \ bet one to five credits and BIG MONEY \ 25 cent \ 5 credits video poker games. In order to activate the gaming machine the player inserts money into the coin entry or bill validator (not shown). In the present example, Player inserts $10.00 into a bill validator—credit $10.00 125 . This is the same video poker game illustrated in FIG. 1, only now if the player chooses to play two or more games he or she can also play BIG MONEY.
[0127] Player selects two games 220 and BIG MONEY 260 . In FIG. 22 player selects play max credits 50 then selects place bet game one 130 . In FIG. 23, Player selects play max credits 50 then selects place bet game two 140 . In FIG. 24, Player selects play max credits 50 then selects place bet BIG MONEY 270 . Player then selects Deal 70 .
[0128] In FIG. 25, five cards are displayed, player holds Ace of Clubs and Ace of Spades in game one 130 . In game 2, five cards are displayed, with Player holding the Queen of Clubs and the Queen of Diamonds 140 . Player selects Draw 90 .
[0129] In FIG. 26, in game one three new cards are displayed, the 3 of Clubs, 8 of Hearts, and the Ace of Diamonds. Player receives three-of-a-kind—winner paid 15 credits on game one 130 . In game two, three new cards are displayed: the 3 of Hearts, 5 of Diamonds, and the Queen of Clubs. Player receives three-of-a-kind—winner paid 15 credits game two 140 . Player received two three-of-a-kinds, BIG MONEY winner paid 30 credits 280 . FIG. 28 shows a representation of a video touch screen displaying information and three independent video poker games in a multi game, denomination and wager format.
[0130] [0130]FIG. 29 shows a representation of a video touch screen displaying information and two independent video poker games with Bonus Pays in a multi game, denomination and wager format. FIG. 30 shows a representation of a video touch screen displaying information and two independent video poker games and Big Money in a multi game, denomination and wager format.
[0131] [0131]FIG. 31 is a representation of a video touch screen displaying information, MACHINE ONE'S identification for group play 500 and an independent conventional jacks or Better \ 25 cent \ bet one to five credits and video poker games. This is the same video poker game illustrated in FIG. 1, only now the player on MACHINE 1 chooses to participate in BIG MONEY GROUP PLAY 510 .
[0132] In FIG. 32 player on MACHINE 1 selects to play with another player on eligible MACHINE 2 520 and also selects to place bet on BIG MONEY GROUP PLAY 530 . FIG. 33 shows a representation of a video touch screen displaying information and BIG MONEY GROUP PLAY bet two credits 540 and MACHINES 1&2 are participating in BIG MONEY GROUP PLAY 550 .
[0133] [0133]FIG. 34 is a representation of a video touch screen displaying information, MACHINE TWO'S identification for group play 560 and an independent conventional jacks or Better \ 25 cent \ bet one to five credits and video poker games. This is the same video poker game illustrated in FIG. 1, only now the player chooses to participate in BIG MONEY GROUP PLAY 570 .
[0134] In FIG. 35 player on MACHINE 2 selects to play with another player on eligible MACHINE 1 580 and also selects to place bet on BIG MONEY GROUP PLAY 590 .
[0135] [0135]FIG. 36 shows a representation of a video touch screen displaying information and BIG MONEY GROUP PLAY bet two credits 600 and MACHINES 2&1 are participating in BIG MONEY GROUP PLAY 610 .
[0136] My invention has been disclosed in terms of a preferred embodiment thereof, which provides an improved single and multi format gaming machine and method for combination and/or simultaneous play that is of great novelty and utility. Various changes, modifications, and alterations in the teachings of the present invention may be contemplated by those skilled in the art without departing from the intended spirit and scope thereof. It is intended that the present invention encompass such changes and modifications. | An electronic gaming device having a plurality of games available for selection by a user allows selection of multiple games for concurrent play. One or more of the multiple games selected by the user in turn are utilized to create composite pay tables. These selection-dependant pay tables in turn provide the basis for additional betting opportunities for the user. The networking of multiple electronic gaming devices having the concurrent play feature provides multiple users with the betting opportunities embodied in these composite pay tables. | 50,421 |
FIELD OF THE INVENTION
The invention relates to a circuit arrangement for the protection of data, particularly tariff data and variable control data, in write-read memories (RAM) which are constructed as volatile memories, in interaction with a microcomputer system of a taximeter which is protected by means of buffer elements against supply voltage breakdowns. This circuit arrangement is intended to protect against manipulation and loss or unauthorized modification of the stored information.
BACKGROUND OF THE INVENTION
The microcomputer system of a taximeter consists essentially of an arrangement of a microprocessor with memories, input-output elements and supply modules which are combined as a system and which can decide, compute, display and store data by means of a predeterminable program based on the input of distance and/or time signals. A much-accepted type is the MOS microprocessor (for instance Intel 8049) which works, for instance, with an eight bit word length compared to the bipolar embodiments. As a part of the microcomputer system, the microprocessor or CPU serves for the processing of data according to a predeterminable rule. The directions for the latter are stored in a read-only memory or ROM as thus identified instructions and they represent the internal working program of the system. Information is fed one time into the read-only memory (ROM) and remains there permanently. The function of the ROM is limited so that the memory content can be read out. In the case of this application, the ROM serves primarily for program storage. However, during each change of information, the ROM must be exchanged for a new ROM which is programmed with correspondingly changed data. In the case of taximeters, the tariff data which form the basis for calculation of a fare are also subject to such changes. In known taximeters, one supplied the changed tariff data into a separate, exchangeable, programmable ROM (PROM) and, at the appropriate point in time when the new tariff became effective, it was exchanged for the present module (PROM). Of course, considerable effort is expended in this mode of operation when the tariff changes frequently.
In addition, a write-read memory (RAM) for the processing of variable data is provided in the microcomputer system. Since information can be read in the RAM and again read out at random in an advantageous manner, this type of memory is extremely suitable for the storage of data or the intermediate storage of data, however, care must be taken that the feed voltage is not lost because the information may be falsified or may be lost due to a voltage breakdown.
It is therefore absolutely necessary in the storage of information in write-read memories (RAM) which are constructed as volatile memories, to provide suitable measures which activate a protective device in dependence on power supply failures or the decrease of supply voltages below a predetermined value and these protective devices guarantee that the information remains in the RAM.
A known circuit arrangement for bridging power supply failures consists in that, for instance, a buffer battery is assigned to the RAM area which saves the stored information temporarily. However, it has been found that, in addition, for instance during power supply failure, due to capacities or inductances in the computer system or the power supply part, undefined voltage conditions result which may falsify information stored in the write-read memory (RAM). In addition to protecting the supply voltage for the RAM area by means of a buffer battery, also for protection of the information in the RAM, an additional measure is necessary which prevents all undefined voltage pulses which result during power supply failure in the system and which may act as interference pulses from affecting the RAM area.
In this connection, according to the German Patent No. 28 03 202, a circuit arrangement for the protection of data during power supply failure or decreasing supply voltage is specified for information stored in write-read memories (RAM) which are constructed as volatile memories. As measures for protection of information in the RAM during voltage failure or decrease of the supply voltage below a minimum value, a voltage monitoring circuit is provided which, in the case of protection, i.e., only during voltage decrease, takes over the supply of the RAM area with operating voltage from a charge storage or long-term storage of a decoupling network. The decoupling network then also controls a RAM write blocking circuit whereby any change of information in the RAM area is prevented before any interference pulses are present. In summary, this known device serves exclusively for protection of information in the RAM during voltage failure of the computer system.
During the normal operation of a system, i.e., during correct operating voltage conditions, the known system does not offer adequate protection, for instance, for tariff data and/or control data in an RAM of a taximeter since, due to any system interferences or manipulations, it would be conceivable to feed erroneous information into the RAM.
It is an object of the invention to provide a circuit arrangement for the permanent protection of data, particularly of tariff data and control data, in a volatile write-read memory (RAM) of a taximeter, wherein the measures for protection can only be cancelled by means of an authorized action in the circuit arrangement.
SUMMARY OF THE INVENTION
The object of the invention, referred to above, is achieved according to the invention by means of a control circuit which is incorporated in the signal line between the microcomputer system and the write-read memory (RAM). By means of this control circuit, in the calibrated state of the system, a suppression of write instructions can be set in such a way that maintenance of the stored data in the RAM is guaranteed.
The advantages of using a write-read memory (RAM) which is constructed as a volatile memory can generally not be overlooked for data storage. The advantages lie particularly in the characteristic of the RAM memory which makes available, on a relatively economical basis with this component, a storage means into which, in a simple manner, information may be read in and read out as often as desired. This ability is very convenient in the application in a taximeter in the characteristic as a tariff data and control data storage. Since, however, RAM's as storage means are in connection with all data, address and control lines with a microprocessor system, it must be ensured by means of additional circuit measures that unintentional information from the system cannot cause a change in the stored data in the RAM due to a case of interference as well as due to attempted manipulation. With the control which is incorporated in the write-signal line between the microcomputer system and the RAM, a total or partial preselectable suppression of write instructions can be set. By means of the circuit arrangement for the prevention of the recording possibility of the RAM, for instance, for tariff data and with a simultaneously effective decoupling of the operating voltage of the system and buffering of the supply voltage of the RAM during normal operating condition of a taximeter, it is achieved without great expenditure that the data stored in the RAM cannot be influenced by any uncontrolled interferences. During a simultaneous use of the RAM for feeding in tariff data and variable control counter data, the control circuit has measures by means of which parts of the RAM, for instance those parts characterized by a special address range, can be blocked against recording of information, so that a data interrogation can always be triggered, but any action in the sense of a data modification remains without effect for the characterized part of the memory. Due to the measure of a controlled prevention of the possibility to write in the RAM, it is possible during normal operation of a taximeter to absolutely protect the content of information of the memory which is volatile per se.
In order to finally utilize the characteristic of reading in information into the RAM in an advantageous manner, particularly in connection with a change of tariff data, the switching element for prevention of a write effect consists, for instance, of a sealable switch by means of which, during normal operation of the taximeter, the write signal can be blocked, however, it can be released for a programming operation. The latter process is limited, for instance, to an input of new or changed tariff data which may only be performed by a group of persons with the authority for this task. Due to the possibility to change the tariff data by means of suitable switching elements in the control circuit, tariff changes can be performed as often as desired without any expenditure for new parts. To release the write-blocking circuit for a required change in the tariff data, also a code switching mechanism may be used. Finally, instead of the code switching mechanism, suitable optically or magnetically acting devices may be used in order to guarantee an effect on the control circuit in the case of a required change in the tariff data.
For a better understanding of the present invention, reference is made to the following description and accompanying drawings, while the scope of the present invention will be pointed out in the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 shows a schematic circuit arrangement with a microcomputer system for taximeters including a circuit device for the protection of tariff data in a volatile memory (RAM);
FIG. 2 shows a schematic circuit arrangement according to FIG. 1 including a circuit device for the protection of tariff data, stored in a specific address range of a volatile memory (RAM).
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention is directed to storage of tariff and control data in an electronic taximeter and the protection of these data against unauthorized changes caused by system interferences or attempted manipulation. An electronic taximeter is essentially comprised of a microcomputer system 1 which is usually a combination of a microprocessor 2 or CPU (central processor unit), a program memory or ROM3 (read-only memory), a write-read memory 4 or RAM (random access memory), a control unit 5 or bus control and a clock generator 6 or clock. Depending on the functional importance and the structural interconnections of the device, the required components are combined to component groups and are arranged according to their hardware on appropriately designed, printed circuit boards. These printed circuit boards can be connected with one another by means of suitable plug connections whereby simultaneously, if possible, all necessary conducting lines between the component groups are established. A further description of all component groups is not necessary for the explanation for the connections of the circuit arrangement according to the invention and for this reason they are only indicated generally.
Functional decisions, calculating processes, control processes, storage of data, etc., are handled in an electronic taximeter in the component group which is to be identified with the term "logic". The core of the logic is, as shown in FIG. 1, the microcomputer system 1 with the central microprocessor 2 or CPU as the component which performs the functional sequences. For supply with operating voltage, the microcomputer system 2 is connected by means of a line 7 with a power supply which is adapted to the requirements, but not further shown. For representation of the processes, particularly for the continuous display of results, storage data, control counter data and other information which is important for the operation of the taximeter, the corresponding called-up data are shown by means of a display bus 8 in a multiple display field which is arranged in accordance with the importance of the data. Finally, the microcomputer system 1 receives via a generator signal line 9 by means of appropriately prepared signals from a generator input circuit which are evaluated, for instance, as distance units for conversion to fare units, using predetermined computation rules in the logic. As is known, in addition to distance units, time units are also included in the computation of a fare unit. The decision which of the two units are included in the form of a signal course, or whether both signal frequencies are included in a specific relation to one another for the determination of the fare, is made by the logic based on a working program which is determined by the corresponding tariff structure.
As is also known, the basis for a fare unit is the tariff which is established for local conditions. Due to this requirement and also due to the continuous adaptation of the fares to the continuously rising expenses, the taximeter or the hardware areas must be adaptable to any specified tariff situation.
The memory module which is on the market as a volatile write-read memory 10 or RAM has proven to be particularly suitable for storage of tariff data as well as repeated changes of these data at certain intervals as long as one is successful in achieving an absolute protection of the tariff data, stored in the RAM. A protective measure must be directed to the ordinary case of interference, such as system interferences or power supply failures, as well as also to the attempted case of interference due to manipulation of the stored data during normal operation of the taximeter. The RAM 10 is functional as a tariff data storage, separately from the central microcomputer system 1, as shown in FIGS. 1 and 2, and is connected with all data, address and control lines to the microcomputer system 1. According to the embodiment of FIG. 1, for the storage of tariff data, a separate RAM 10 is provided; correspondingly, in order to hold continuously variable data, such as, for instance, the control counter data, a RAM 11 is arranged. By means of a bidirectional counter data bus 12 controlled by the control mechanism in the microcomputer system 1, the flow of data takes place between the microcomputer system 1 and the called-up memory RAM 10 or 11.
While the RAM 11 can be switched during normal operation of the taximeter by means of control signals from the microcomputer area 1 selectively according to the operating program to write or read processes, the function of the RAM 10 remains limited to merely making available the stored tariff data for the read-out process. In the exceptional case, i.e., in the case of an intentional change of the tariff data, also the RAM 10 can be set by actuating a control circuit 13 which is still to be explained below for a write process.
For the selection of the data to be read out or for feeding in of data to be stored, the RAM 10 and 11 are connected by means of an address bus 14 with the microcomputer system 1. Corresponding signals for reading or writing are conducted into the RAM 10 by means of the internal control unit 5 or the control bus and a read-signal line 15 as well as a write signal line 16. For the transfer of a write-signal into the RAM 10 which is intended exclusively for tariff data, the write-signal line 16 is connected by means of a control circuit 13 and a write-connecting line 17 with the RAM 10. Due to the control circuit 13, it is possible, by means of additional switching elements in the control circuit 13, to let an intentional write-signal reach the RAM 10 exclusively by means of influencing the control circuit 13 separately from the system. Due to the interconnection of the control circuit 13, for the normal operation of a taximeter, a permanent suppression of the write instruction, which in its simplest form is represented as a write pulse on a signal line 16 to the RAM 10, can be set. In this way, it is absolutely prevented that the system can change the data stored as tariff data in the RAM 10 in any manner.
To restrict the influence on the control circuit 13 to an authorized circle of personnel, the control circuit 13 has, for instance, a sealable switch 18 which interrupts a write signal for the RAM 10 or generates a blocking signal by means of which any flow of information into the RAM 10 is prevented. In order to make it more difficult to influence the control circuit 13, also a code switching mechanism may be provided by means of which a switch 18 to produce the connection of the write-signal line with the RAM 10 can be controlled. In another embodiment, it is conceivable to influence the control circuit 13 by means of an optical device in order to make possible to write in the tariff RAM 10 with new tariff data. In another embodiment of the control circuit 13, the tariff RAM 10 can also be charged by means of magnetic control elements and the use of Reed switches. The different specified types of external action on the control circuit 13 in the sense of a specified tariff data change are indicated according to FIGS. 1 and 2 by a line 19.
For storage of the variable control data, according to the embodiment of FIG. 1, an additional write-read memory (RAM) 11 is provided which for read-in and read-out of data is also connected by means of the data bus 12 and the address bus 14 with the microcomputer system 1. In a storage of variable control data, for a continuous modification of the memory contents, the write-signal line 16 and the read-signal line 15 are connected directly with the bus control unit 5. To supply the RAM 10 and 11 with operating voltage, for protection of the voltage supply and for protection against any operating voltage breakdowns, one decoupling diode 20 is always provided in the line 21 to the operating voltage source of the system. An additional decoupling diode 22 is always in the voltage supply line from a buffer battery 23, shown in FIG. 1. Finally, the circuit arrangement contains, for decoupling and buffering of the supply voltage, a buffer capacitor 24 which is connected on the one side to ground and with its second connection is connected with the voltage supply lines 21 and 25 as well as by means of a line 26 with the RAM 10 and 11 for continuous supply and maintenance of the memories with operating voltage.
In another embodiment of the circuit arrangement according to the invention, for the mutual storage of tariff data and variable data (for instance, control counter data), one single write-read memory (RAM) module 27 is used (FIG. 2). The RAM 27 is divided into correspondingly required storage areas for fulfillment of the storage tasks of secured tariff data, on the one hand, and variable control counter data, on the other hand. In order to also here achieve to the same extent the absolute protection of the tariff data against unauthorized changes, the control circuit 13 is expanded in that additional switching elements 28 are provided by means of which specific address areas in the RAM which are assigned to the storage of tariff data can be blocked for incorrect writing. For this purpose, the address bus 14 is guided with respect to the signal lines 29 for the memory address for tariff data over the control circuit 13 where appropriate memory areas can be addressed by means of the switching element 29. In the memory sector which can be blocked by means of the switching element 28, in the sealed state of the taximeter, the storage areas are readable but not writable. Accordingly, in interaction with the write-signal block which is arranged in the same control circuit 13, the tariff data stored there cannot be changed. As already explained in connection with FIG. 1, a change can be only undertaken by authorized persons by externally acting by influencing a line 19. Regarding the safety measures against falsification of the contents of information of the RAM 27 based on a voltage breakdown or loss, the same measures apply for the circuit arrangement according to FIG. 2, as were explained for the circuit according to FIG. 1.
While the foregoing description and drawings represent the preferred embodiments of the present invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the true spirit and scope of the present invention. | A circuit arrangement for the permanent protection of data in volatile write-read memories (RAM) such as the type used for the storage of tariff data and variable control counter data in a taximeter. The inventive circuit arrangement provides a signal line between the microcomputer system and a volatile write-read memory (RAM) via a control circuit. By means of this arrangement, in the sealed state of the taximeter, a permanently effective suppression of write instructions can be set. Thus, the data stored there can no longer be affected by any interference signals from the microcomputer system. The supply of operating voltage of the RAM is secured by means of a circuit which includes a buffer battery and a buffer capacitor. | 20,589 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This is a continuing application, under 35 U.S.C. § 120, of copending international application No. PCT/EP2003/006691, filed Jun. 25, 2003, which designated the United States; this application also claims the priority, under 35 U.S.C. § 119, of German patent application No. 202 09 839.7, filed Jun. 25, 2002; the prior applications are herewith incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
[0002] The present invention relates to a configuration with a condenser and an evaporator shell for a refrigerating device, such as for instance a refrigerator or freezer cabinet.
[0003] In the case of a refrigerator, moisture given off by the refrigerated items to the air in the interior space of the refrigerator or moisture introduced by opening the door condenses on the evaporator. This moisture must be removed from the interior space of the refrigerator. For this purpose, a collecting channel which collects the moisture flowing off from the evaporator is generally fitted to a wall of the interior space, underneath the evaporator. From the lowest point of the collecting channel, a duct through which the water can flow away from the interior space is led through the housing wall of the refrigerator. This duct opens out in a conventional way into an open shell in which the water can evaporate. The shell is arranged above the condenser of the refrigerator, in order to warm up the water with the waste heat of the condenser and in this way speed up its evaporation.
[0004] Such evaporator shells are also used in the case of freezers with automatic defrosting, so-called no-frost appliances, in which the evaporator is artificially heated up from time to time in order to thaw frost which has been deposited on it.
[0005] Such a shell must be fitted as close as possible to the condenser in order to achieve adequate heating that ensures that the shell does not run over during operation and allow water to flow onto the condenser. In order to achieve such a close proximity between the condenser and the evaporator shell that is also consistent from appliance to appliance in mass production, the shell is generally not mounted on housing parts of the refrigerating device but directly on the condenser.
[0006] A known possible way of mounting the shell is to make it engage in a latching manner on pipe connecting pieces of the condenser. However, this is unsatisfactory from the aspect of a firm and reliable attachment of the evaporator shell, since a maximum of two fastening points are available on the inlet line and outlet line of the condenser and the distance between the pipe connecting pieces and the evaporator shell can be great.
[0007] The technique used at present by the assignee, BSH Bosch und Siemens Hausgeräte GmbH of Munich, Germany, therefore uses flat pins which are welded onto the upper side of the condenser in order to mount the evaporator shell on it. With this technique, the evaporator shell can indeed be mounted firmly and securely and also with a reproducible position with respect to the condenser, but it has the disadvantage that the welding is labor-intensive, because the places on the condenser housing that are intended for attaching the pins have to be ground smooth in advance, and that the possibility of damage to the condenser housing caused by careless welding cannot be ruled out. If a hole is formed in the housing of the condenser during welding, this damage cannot be rectified cost-effectively, and the condenser has to be scrapped.
SUMMARY OF THE INVENTION
[0008] It is accordingly an object of the invention to provide a condenser/evaporator assembly, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which provides for a condenser-evaporator shell configuration that can be implemented in a simple and cost-effective manner.
[0009] With the foregoing and other objects in view there is provided, in accordance with the invention, a configuration for a refrigerating device, comprising:
a condenser for the refrigerating device, the condenser having a housing formed with an upper half-shell and a lower half-shell, the upper half-shell carrying latching flanks; an evaporator shell mounted to the housing of the condenser, the evaporator shell bearing retaining claws configured to engage behind the latching flanks on the upper half-shell of the housing.
[0012] The latching flanks of the upper half of the shell can be already formed with little effort by machining during the production of the shell, before the condenser is assembled. The assembly of the configuration according to the invention can therefore take place in a simple way, in that the shell is simply pressed onto the condenser until it engages, or by placement and subsequent turning in the manner of a bayonet fastener.
[0013] To simplify the assembly, it is desirable that the upper half-shell has a basic shape which is rotationally symmetrical about an axis, and that the latching flanks are arranged at the same height with respect to this axis. In this way it is possible to mount the evaporator shell in many different orientations corresponding to the degree of symmetry; searching for an orientation of the shell that is suitable for mounting is made easier in this way, or made entirely superfluous.
[0014] In accordance with an added feature of the invention, the latching flanks are formed on at least one projection or at least one groove of the upper half-shell. This may be, in particular, a single, peripheral projection or a number of projections that are separate from one another and distributed at regular angular intervals around the periphery of the half-shell; in a corresponding way, the groove may also extend over the entire periphery of the half-shell, or a number of grooves extend in a plane over separate peripheral portions of the half-shell.
[0015] The retaining claws are preferably flexible, so that they are spread apart when the evaporator shell is fitted onto the upper half-shell, in order to be able subsequently to engage behind the latching flanks.
[0016] It may also be desirable to be able to use rigid retaining claws, such as for instance if the evaporator shell is formed from a rigid material and the retaining claws are intended to be in one part with the shell. In this case, latching engagement of the evaporator shell can be achieved in a simple way if the projections are separated in the peripheral direction of the upper half-shell by intermediate spaces, the width of which corresponds at least to the width of the retaining claws, so that the latter can be led through between the projections when the evaporator shell is placed onto the condenser, and can be made to engage on these during subsequent turning.
[0017] Other features which are considered as characteristic for the invention are set forth in the appended claims.
[0018] Although the invention is illustrated and described herein as embodied in a condenser-evaporator shell configuration for a refrigerating device, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
[0019] The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0020] FIG. 1 shows a schematic, partly cut-away, perspective view of the upper part of a condenser with an evaporator shell mounted thereon;
[0021] FIG. 2 is a perspective view of the complete evaporator shell from FIG. 1 ; and
[0022] FIG. 3 is a section taken through the upper part of a condenser with an evaporator shell mounted on it according to a second configuration of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a perspective view of the upper part of the housing 1 of a condenser for a refrigerating device and, halved, an evaporator shell 2 mounted on it. An upper half-shell 1 and a lower half-shell 9 , only represented in part, are connected by a weld seam 10 . The lower half-shell 9 bears four fastening lugs 11 for screwing the condenser in a refrigerating device, only one of which can be seen in the figure. The half-shell 1 is a round dome, which is formed as one part from sheet metal by deep-drawing. Three rib-shaped projections 3 are formed out of the dome shape. These ribs 3 extend in each case about 60° in the same plane perpendicular to the vertical axis of symmetry of the dome.
[0024] The evaporator shell 2 shown in its entirety in FIG. 2 has a base 4 , which is adapted to the dome shape of the upper half-shell 1 . Arranged at the edge of the base 4 , where the latter meets the side wall of the evaporator shell 2 , are three retaining claws 5 . These likewise extend in each case over an angle of just 60° and are uniformly distributed over the periphery of the evaporator shell 2 . In this way it is possible to mount the evaporator shell 2 by initially placing it onto the half-shell 1 in an orientation in which the retaining claws 5 reach through the intermediate spaces between adjacent ribs 3 and subsequently turning the evaporator shell 2 , so that the retaining claws 5 come into contact with latching flanks 7 on the underside of the ribs 3 and in this way keep the evaporator shell 2 pressed against the upper half-shell 1 .
[0025] The evaporator shell 2 according to this exemplary embodiment may be produced as one part from a rigid material, since the mounting does not require any significant deformation of the retaining claws 5 .
[0026] In the case of an alternative configuration, the three ribs 3 are replaced by one rib extending over the entire periphery of the half-shell 1 . In this case, the retaining claws of the evaporator shell must be flexible, in order that the evaporator shell can be mounted on the continuous rib by fitting it on, with the retaining claws being bent outward. For this purpose, the entire evaporator shell may be formed from a flexible material, or flexible retaining claws may be joined onto an otherwise rigid evaporator shell, for example formed on by injection-molding around it.
[0027] If the material of the retaining claws is not only flexible but also extensible, the retaining claws may also be formed as a closed ring, extending over the entire periphery of the evaporator shell 2 .
[0028] In the case of the second configuration of the configuration according to the invention, shown in section in FIG. 3 , the evaporator shell is fastened to a peripheral groove 6 , which is recessed in the upper half-shell 1 . Here, too, the retaining claws 5 engaging in the groove 6 may also be distributed as a plurality over the periphery of the evaporator shell 2 , or they may form a single closed ring.
[0029] Latching flanks 7 for anchoring the evaporator shell are formed here by the upper side wall of the groove 6 . | An evaporator shell is mounted on the half-shell of a condenser housing. The evaporator shell is retained with the aid of retaining claws that engage from the rear with catching flanks formed on the upper half-shell. | 11,882 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an autotensioner which is used to apply appropriate tension to the timing belt of an automotive engine or to a belt for driving auxiliary machinery, for example, an alternator, compressor, etc.
2. Description of the Prior Art
To drive a cam shaft of an OHC or DOHC type engine to rotate synchronously with the crankshaft, a drive mechanism that employs a timing belt 1, such as that shown in FIG. 14, is widely used.
In FIG. 14, reference numeral 2 denotes a driving pulley that is driven to rotate by the crankshaft of an engine, 3 a driven pulley that is secured to an end portion of a cam shaft, and 4 a tension pulley for applying appropriate tension to the timing belt 1.
The tension pulley 4 is, as shown in the enlarged view of FIG. 15, rotatably supported by a portion of a pivoting member 6 that pivots about a fixed shaft 5, the portion being eccentric with respect to the fixed shaft 5. A tension spring 8 is connected at one end thereof to the distal end portion of an arm piece 7 that is secured at its proximal end to the pivoting member 6, thereby applying resilient force to the pivoting member 6 in a direction in which the tension pulley 4 is resiliently pressed against the timing belt 1, and thus maintaining the tension in the timing belt 1 at a constant level irrespective of a change in the size of the timing belt 1 caused by a temperature change, for example, or oscillations of the belt 1 caused by the operation of the engine. This machanism is generally known as autotensioner.
The conventional autotensioner, however, involves the following problems.
When the driving pulley 2 in the arrangement shown in FIGS. 14 and 15 rotates counterclockwise, as shown by an arrow a in FIG. 14, the left half of the timing belt 1 tends to become taut, while the right half tends to become slack.
The autotensioner, which includes the tension pulley 4, is provided at the right half of the timing belt 1, that is, the portion of the belt 1 which tends to become slack. However, when the engine comes to a stop, it is likely to momentarily rotate in the reverse direction. During this moment, the right half of the timing belt 1 tends to become taut.
If the tension pulley 4 directly follows the movement of the timing belt 1 when such a sudden change in tension occurs, a large amount of slack momentarily occurs in the timing belt 1. In an extreme case, the slack in the timing belt 1 causes an undesired shift in the mesh between the belt 1 and the toothed pulleys (driving and driven pulleys 2 and 3), resulting in a difference in the phase of rotation between the engine crankshaft and the cam shaft.
To solve this problem, damper resistance that occurs between the fixed shaft 5 and the pivoting member 6 may be utilized in such a manner that the tension pulley 4 will not immediately follow a sudden change in the tension. In such a case, however, when the tension pulley 4 is rotating in a normal state (i.e., tension variations are small), it may be unable to follow fine oscillations of the timing belt 1. Thus, this arrangement may cause oscillations of the timing belt 1.
Under these circumstances, Japanese Patent Public Disclosure (KOKAI) No. 63-167163 discloses an invention wherein an oil damper mechanism and a roller-type one-way clutch are provided around the fixed shaft 5 so that the tension pulley 4 immediately follows the movement of the belt 1 only when the belt 1 becomes slack.
The disclosed invention suffers, however, from a lack of durability due to the following reasons: it is difficult to lubricate the roller type one-way clutch; fretting corrosion is likely to occur due to the type of structure; and the tension in the belt is supported by a roller.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an autotensioner which is free from the above-described problems of the prior art.
The autotensioner of the present invention has a fixed shaft, a pivoting member which is rotatably supported around the fixed shaft, at least the proximal portion of the member having a cylindrical configuration, a pulley which is rotatably supported around a pivot shaft that is a part of the pivoting member, the pivot shaft being parallel to the fixed shaft, and a spring which presses the pulley against a member to which tension is to be applied, in the same way as in the conventional autotensioner stated above.
The autotensioner of the present invention further has an annular space which is provided between the outer peripheral surface of the fixed shaft and the inner peripheral surface of the pivoting member, the space being filled with a viscous fluid, a first partition wall which is formed on a part of the outer peripheral surface of the fixed shaft, the partition wall having its outer peripheral edge in close proximity to the inner peripheral surface of the pivoting member to partition the annular space circumferentially, and a second partition wall which is formed on a part of the inner peripheral surface of the pivoting member, the second partition wall having its inner peripheral edge in close proximity to the outer peripheral surface of the fixed shaft to partition the annular space circumferentially, thus the second partition wall being moved within the viscous fluid that fills the annular space.
According to a first aspect of the present invention, which corresponds to the appended claim 1, the above-described autotensioner has a passage which is provided circumferentially in at least either one of the first and second partition walls, and a check valve which is provided in the intermediate part of the passage, the check valve being arranged to open the passage only when the pulley is moved by the resilient force of the spring.
According to a second aspect of the present invention, which corresponds to the appended claim 3, the above-described autotensioner has a passage which is defined by a space that is formed by separating at least either one of the outer peripheral edge of the first partition wall and the inner peripheral edge of the second partition wall from a peripheral surface that faces the peripheral edge concerned, and a check valve which is provided in the intermediate part of this passage, the check valve being arranged to open the passage only when the pulley is moved by the resilient force of the spring.
The autotensioner of the present invention, arranged as described above, functions as follows.
When the tension in a belt, to which appropriate tension is to be applied by the autotensioner, is suddenly increased at a part thereof which is pressed by the pulley that is supported on the pivoting member through the pivot shaft, the pivoting member is caused to pivot suddenly against the resilient force of the spring and consequently the second partition wall that is formed on the inner peripheral surface of the pivoting member is caused to move within the viscous fluid that fills the annular space.
However, when the pulley is caused to move against the resilient force of the spring in this way, the check valve, which is provided in the intermediate part of the passage that is provided in at least either one of the first and second partition walls (in the case of the appended claim 1) or the passage that is formed in between either one of the outer peripheral edge of the first partition wall and the inner peripheral edge of the second partition wall and a peripheral surface that faces the peripheral edge concerned (in the case of the appended claim 3), is left closed. Accordingly, strong resistance acts on the second partition wall when moving within the viscous fluid that fills the annular space, so that the pivoting member is only allowed to move slowly and effectively, thus enabling the pulley to follow slowly and effectively the movement of the belt in which the tension is increased suddenly. Thus, the other part of the belt is prevented from becoming excessively slack.
Conversely, when a part of the belt which is pressed by the pulley suddenly becomes slack, the check valve that is provided in the passage opens, so that resistance to the second partition wall that moves within the viscous fluid decreases. Accordingly, the pivoting member is allowed to pivot rapidly by the resilient force of the spring, thus enabling the pulley to follow the slack in the belt.
In short, the autotensioner of the present invention acts in such a manner that, when a part of the belt that is in contact with the pulley becomes tense, the pulley slowly and effectively follows the movement of the belt, whereas, when that part of the belt becomes slack, the pulley rapidly follows the movement of the belt, thus preventing, in either case, occurrence of excessive slack in any part of the belt.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 to 5 show in combination a first embodiment of the present invention, in which:
FIG. 1 is a sectional view showing the whole structure of the embodiment;
FIG. 2 is a sectional view taken along the line A--A in FIG. 1;
FIG. 3 shows only a pivoting member as viewed from the right-hand side of FIG. 1; and
FIGS. 4 and 5 are enlarged views of the part B of FIG. 2, FIG. 4 showing the behavior of a check valve when a belt becomes slack, and FIG. 5 showing the behavior of the check valve when the belt becomes taut.
FIGS. 6 to 9 show in combination a second embodiment of the present invention, in which:
FIG. 6 is a sectional view showing the whole structure of the embodiment;
FIG. 7 is a sectional view taken along the line C--C in FIG. 6; and
FIGS. 8 and 9 are enlarged views of the part D of FIG. 7, FIG. 8 showing the behavior of the check valve when the belt becomes slack, and FIG. 9 showing the behavior of the check valve when the belt becomes taut.
FIGS. 10 to 13 show in combination a third embodiment of the present invention, in which:
FIG. 10 is a view corresponding to a sectional view taken along the line C--C in FIG. 6;
FIG. 11 is an exploded perspective view of a check valve that is employed in the third embodiment; and
FIGS. 12 and 18 are enlarged views of the part E of FIG. 10, FIG. 12 showing the behavior of the check valve when the belt becomes slack, and FIG. 13 showing the behavior of the check valve when the belt becomes taut.
FIG. 14 is a front view of a timing belt driving mechanism of an engine, which is provided with an autotensioner; and
FIG. 15 is a front view showing one example of conventional autotensioners, which is incorporated in the timing belt driving mechanism shown in FIG. 14.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The present invention will be described below in more detail by way of embodiments and with reference to the accompanying drawings.
FIGS. 1 to 5 show in combination a first embodiment of the present invention, in which: FIG. 1 is a sectional view showing the whole structure of the embodiment; FIG. 2 is a sectional view taken along the line A--A in FIG. 1; FIG. 3 shows only a pivoting member as viewed from the right-hand side of FIG. 1; and FIGS. 4 and 5 are enlarged views of the part B of FIG. 2, FIG. 4 showing the behavior of a check valve when a belt becomes slack, and FIG. 5 showing the behavior of the check valve when the belt becomes taut.
Reference numeral 9 denotes a fixed shaft which is in the form of a cylinder that has a flange portion 9a which is formed along the outer peripheral surface of a portion which is closer to the proximal end (the right end as viewed in FIG. 1). When the autotensioner is to be used, the fixed shaft 9 is secured by means of a bolt 10 to the front side of the cylinder block of an engine (in the case where the autotensioner is designed for a timing belt).
Reference numeral 11 denotes a pivoting member which comprises a short cylindrical proximal portion 12 which fits on the flange portion 9a, and a pivot portion 13 which projects from the outer end face (the left end face as viewed in FIG. 1) of the proximal portion 12, the pivot portion 13 being eccentric with respect to the proximal portion 12. A pulley 14 is rotatably supported around the pivot portion 13 through a rolling bearing 36. The pivot portion 13 is fitted on the distal end portion of the fixed shaft 9 through a sliding bearing 16.
Reference numeral 15 denotes a torsion coil spring for application of resilient force to pivot the pivoting member 11. One end of the spring 15 is retained by a proximal end portion of the fixed shaft 9 which projects from the flange portion 9a, while the other end of the spring 15 is retained by the proximal end portion of the pivoting member 11.
In consequence, the pivoting member 11 is caused to pivot about the pivot portion 13 by the resilient force of the torsion coil spring 15, and the pulley 14 that is supported around the pivoting member 11 is movable in response to the pivotal motion of the member 11 by an amount corresponding to the eccentricity of the pivot portion 13 with respect to the fixed shaft 9.
The above-described arrangement is the same as that of autotensioners which have heretofore been known. In the autotensioner of the present invention, which is shown in FIGS. 1 to 5, however, an annular space 17 is provided between the outer peripheral surface of the fixed shaft 9 and the inner peripheral surface of the pivoting member 11, and the space 17 is filled with a viscous fluid, for example, oil.
More specifically, a sealing member 18 is provided between the outer peripheral edge of the flange portion 9a and the inner peripheral surface of the proximal portion 12 of the pivoting member 11, and another sealing member 18 is provided between the inner peripheral surface of the proximal end portion of the pivot portion 13 and the outer peripheral surface of the intermediate portion of the fixed shaft 9, thereby preventing leakage of the viscous fluid that fills the annular space 17, which is present between the two sealing members 18.
A first partition wall 19 is formed on the outer peripheral surface of a part of the fixed shaft 9 that is located between the flange portion 9a and the inner side surface 13a of the pivot portion 13. The outer peripheral edge of the first partition wall 19 is in close proximity to the inner peripheral surface of the pivoting member 11, and two side edges of the first partition wall 19 are in close proximity to the flange portion 9a and the inner side surface 13a, respectively. As a result, the annular space 17 is circumferentially partitioned by the first partition wall 19 (FIG. 2).
A second partition wall 20 is formed on the inner peripheral surface of a part of the pivoting member 11 that is located between the flange portion 9a and the inner side surface 13a of the pivot portion 13. The inner peripheral edge of the second partition wall 20 is in close proximity to the outer peripheral surface of the fixed shaft 9, and two side edges of the second partition wall 20 are in close proximity to the flange portion 9a and the inner side surface 13a, respectively. As a result, the annular space 17 is also circumferentially partitioned by the second partition wall 20 (FIG. 2).
The second partition wall 20, which is formed on the inner peripheral surface of the pivoting member 11, is movable within the viscous fluid that fills the annular space 17.
Of the first and second partition walls 19 and 20 that partition the annular space 17 circumferentially, the first partition wall 19, which is formed on the outer peripheral surface of the fixed shaft 9, is provided with a passage 21, which extends circumferentially (perpendicularly to the plane of FIG. 1; horizontally as viewed in FIG. 2).
A valve seat 22, which has an inward flange-like configuration, is formed along the inner peripheral edge of the opening of the passage 21, and a ball 23 is loosely fitted in the passage 21, the ball 23 having an outer diameter that is greater than the inner diameter of the valve seat 22. The ball 23 is resiliently pressed toward the valve seat 22 by means of a compression spring 25 which is provided between the ball 23 and a step 24 that is formed on the inner peripheral surface of the intermediate part of the passage 21. In consequence, the ball 23 and the valve seat 22 comprise a check valve 26 which allows the viscous fluid to flow only in one direction (from the right to the left as viewed in FIGS. 2, 4 and 5) within the passage 21.
It should be noted that the torsion coil spring 15 has a pretorqued resilient force which causes the pivoting member 11 to pivot clockwise as viewed in FIG. 2, and the check valve 26 therefore opens the passage 21 only when the pivoting member 11, which supports the pulley 14, is moved counter to the resilient force of the torsion coil spring 15 (i.e., clockwise as viewed in FIG. 3).
The autotensioner of the present invention, which is arranged as described above, is used in a state where the pulley 14 is brought into contact with a belt to which appropriate tension is to be applied and this pulley 14 is pressed against the belt by the resilient force of the torsion coil spring 15. When, in such a used state, the tension in a part of the timing belt that is pressed by the pulley 14 increases suddenly due to the engine stopping, for example, the pivoting member 11 that supports the pulley 14 at the distal end thereof is caused to pivot suddenly clockwise as viewed in FIG. 2 (i.e., counterclockwise as viewed in FIG. 3) against the resilient force of the torsion coil spring 15.
If, in such a case, the movement of the pulley 14 is allowed as it is, the other part of the belt would become excessively slack, causing problems such as an undesired shift in the mesh between the belt and the toothed pulleys (driving and driven pulleys), as described above.
To solve such problems, the autotensioner of the present invention is designed to function as follows.
When the pivoting member 11 is caused to pivot clockwise as viewed in FIG. 2 by a sudden increase in the tension applied to the belt, the second partition wall 20 that is formed on the inner peripheral surface of the pivoting member 11 is forced to move clockwise as viewed in FIG. 2 within the viscous fluid that fills the annular space 17, causing an increase in the pressure of the viscous fluid at the front side of the second partition wall 20 as viewed in the direction of movement thereof. As a result, the viscous fluid in the annular space 17 is caused to flow clockwise as viewed in FIG. 2.
However, when the pivoting member 11, which supports the pulley 14, moves against the resilient force of the torsion coil spring 15 in this way, the direction of the pressure that is applied to the ball 23 coincides with the direction in which the ball 23 is pressed by the compression spring 25, which is incorporated in the check valve 26 that is provided in the intermediate part of the passage 21 in the first partition wall 19. Accordingly, the check valve 26 is left closed, as shown in FIG. 5, so that strong resistance acts on the second partition wall 20 when moving within the viscous fluid in the annular space 17. Thus, the pivoting member 11 is only allowed to move slowly and effectively.
Accordingly, the pulley 14 is enabled to follow slowly and effectively the movement of the belt in which the tension is suddenly increased, thus preventing the other part of the belt from becoming excessively slack.
Conversely, when a part of the timing belt that is pressed by the pulley 14 suddenly becomes slack, the pivoting member 11 that supports the pulley 14 is caused to pivot counterclockwise as viewed in FIG. 2 (i.e., clockwise as viewed in FIG. 3). In consequence, the second partition wall 20 that is formed on the inner peripheral surface of the pivoting member 11 is forced to move counterclockwise as viewed in FIG. 2 within the viscous fluid that fills the annular space 17. As a result, the viscous fluid in the annular space 17 is caused to flow counterclockwise as viewed in FIG. 2.
Thus, when the pivoting member 11, which supports the pulley 14, is caused to move by the resilient force of the torsion coil spring 15, the direction of the pressure that is applied to the ball 23 is counter to the direction in which the ball 23 is pressed by the compression spring 25, which is incorporated in the check valve 26 that is provided in the intermediate part of the passage 21 in the first partition wall 19. Accordingly, the check valve 26 is opened, as shown in FIG. 4, so that resistance to the movement of the second partition wall 20 within the viscous fluid in the annular space 17 decreases, thus enabling the pivoting member 11 to move rapidly. As a result, the pivoting member 11 is rapidly pivoted by the resilient force of the torsion coil spring 15 to enable the pulley 14 to follow the slack in the belt.
Thus, in the case where the autotensioner of the present invention is used to apply tension to the belt 14, when a part of the belt that is contacted by the pulley 14 becomes tense, that is, when the pivoting member 11 pivots clockwise as viewed in FIG. 2, the pulley 14 slowly and effectively follows the movement of the belt in which the tension is increased, whereas, when the belt becomes slack, that is, when the pivoting member 11 pivots counterclockwise as viewed in FIG. 2, the pulley 14 rapidly follows the belt, thereby preventing occurrence of excessive slack in any part of the belt.
Although in the illustrated embodiment the passage 21 and the check valve 26 are provided in the first partition wall 19, these elements may be provided in the second partition wall 20 and may also be provided in both the first and second partition walls 19 and 20. However, in any case, the check valve 26 must be provided such that it opens the passage 21 only when the pivoting member 11 that supports the pulley 14 is moved by the resilient force of the torsion coil spring 15.
The structure of the check valve 26 is not necessarily limitative to a ball valve such as that illustrated in the figures. It is also possible to adopt other known structures, for example, a reed valve.
A second embodiment of the present invention, which corresponds to the appended Claims 3 and 4, will next be explained.
FIGS. 6 to 9 show in combination a second embodiment of the present invention, in which: FIG. 6 is a sectional view showing the whole structure of the embodiment; FIG. 7 is a sectional view taken along the line C--C in FIG. 6; and FIGS. 8 and 9 are enlarged views of the part D of FIG. 7, FIG. 8 showing the behavior of the check valve when the belt becomes slack, and FIG. 9 showing the behavior of the check valve when the belt becomes taut.
In this embodiment, the outer peripheral edge of the first partition wall 19 that is formed on the outer peripheral surface of the fixed shaft 9 is designed to separate from the inner peripheral surface of the pivoting member 11, thereby defining a passage 27 between the outer peripheral edge and the inner peripheral surface, and a check valve 28 is provided in the intermediate part of the passage 27, which is adapted to open the passage 27 only when the pivoting member 11 that supports the pulley 14 is moved by the resilient force of the torsion coil spring 15.
More specifically, the check valve 28 comprises a roller 30 which is loosely fitted in a recess 29 that is formed in the outer peripheral edge of the first partition wall 19, the depth of the recess 29 being continuously varied circumferentially, and a compression spring 31 which is provided between the roller 30 and the inner side surface of the recess 29 to press the roller 30 toward the shallower side of the recess 29.
In this embodiment, when the pivoting member 11, which supports pulley 14, pivots clockwise as viewed in FIG. 7 in response to a sudden increase in the tension in the belt, the check valve 28 closes the passage 27, as shown in FIG. 9, thereby preventing the pivoting member 11 from moving rapidly, and thus enabling the pulley 14 to follow slowly and effectively the movement of the belt in which tension is suddenly increased.
Conversely, when the belt becomes slack, the check valve 28 opens the passage 27, as shown in FIG. 8, so that no great resistance will act on the pivotal movement of the pivoting member 11, thereby enabling the pulley 14 to follow rapidly the movement of the belt.
Since the other arrangements and functions are the same as those in the above-described first embodiment, including the configuration (see FIG. 3) of the second partition wall 20 that is formed on the pivoting member 11, the same elements or portions are denoted by the same reference numerals, and repeated description thereof is omitted.
A third embodiment of the present invention, which corresponds to the appended Claims 3 and 5, will next be explained.
FIGS. 10 to 13 show in combination a third embodiment of the present invention, in which: FIG. 10 is a view corresponding to a sectional view taken along the line C--C in FIG. 6; FIG. 11 is an exploded perspective view of a check valve that is employed in the third embodiment; and FIGS. 12 and 13 are enlarged views of the part E of FIG. 10, FIG. 12 showing the behavior of the check valve when the belt becomes slack, and FIG. 13 showing the behavior of the check valve when the belt becomes taut.
In this embodiment, the outer peripheral edge of the first partition wall 19 that is formed on the outer peripheral surface of the fixed shaft 9 is designed to separate from the inner peripheral surface of the pivoting member 11, thereby defining a passage 27 between the outer peripheral edge and the inner peripheral surface, and a check valve 32 is provided in the intermediate part of the passage 27, which is adapted to open the passage 27 only when the pivoting member 11 that supports the pulley 14 is moved by the resilient force of the torsion coil spring 15, in the same way as in the second embodiment.
The check valve 32 in this embodiment is, however, comprised of a plate-shaped flapper 33 which is pivotally supported at its inner end portion through a pivot shaft 34 that is attached to the outer peripheral edge portion of the first partition wall 19. The outward pivotal movement of the flapper 33 is limited by the abutment between one side of the flapper 33 and the outer peripheral edge of the first partition wall 19. More specifically, this embodiment has a stopper mechanism wherein, when the flapper 33 pivots outwardly about the pivot shaft 34 until the outer peripheral edge of the flapper 33 comes into close proximity to the inner peripheral surface of the pivoting member 11, one side of the flapper 33 abuts against the outer peripheral edge of the first partition wall 19, as described above, thereby preventing the flapper 33 from pivoting any further.
In addition, a torsion spring 35 is provided between the flapper 33 and the first partition wall 19 to cause the flapper 33 to pivot in a direction in which the outer peripheral edge of the flapper 33 comes into close proximity to the inner peripheral surface of the pivoting member 11.
The operation of this embodiment is similar to that of the second embodiment. That is, when the pivoting member 11, which supports pulley 14, pivots clockwise as viewed in FIG. 10 in response to a sudden increase in the level of tension in the belt, the check valve 32 closes the passage 27, as shown in FIG. 13, thereby preventing the pivoting member 11 from moving rapidly, and thus enabling the pulley 14 to follow slowly and effectively the movement of the belt in which the tension is suddenly increased.
Conversely, when the belt becomes slack, the check valve 32 opens the passage 27, as shown in FIG. 12, so that no great resistance will act on the pivotal movement of the pivoting member 11, thereby enabling the pulley 14 to follow rapidly the movement of the belt.
Although in the second and third embodiments the passage 27 and the check valve 28 (32) are provided in between the outer peripheral surface of the first partition wall 19 and the inner peripheral surface of the pivoting member 11, these elements may be provided in between the inner peripheral edge of the second partition wall 20 and the outer peripheral surface of the fixed shaft 9 and may also be provided both in the area between the outer peripheral surface of the first partition wall 19 and the inner peripheral surface of the pivoting member 11 and in the area between the inner peripheral edge of the second partition wall 20 and the outer peripheral surface of the fixed shaft 9. However, in any case, the check valve 28 (32) must be provided such that it opens the passage 27 only when the pivoting member 11 that supports the pulley 14 is moved by the resilient force of the torsion coil spring 15 (i.e., when the pivoting member 11 moves clockwise, as viewed in FIG. 10).
Although in each of the foregoing embodiments the distal end portion of the pivoting member 11 is arranged to be eccentric with respect to the fixed shaft 9 to define the pivot portion 13 and the pulley 14 is supported on the pivot shaft 13, the stroke of the pulley 14 can also be ensured by an arrangement wherein a pivoting arm is provided on the outer peripheral surface of the pivoting member 11 and the pulley 14 is supported through a pivot shaft that is provided at the distal end of this pivoting arm.
The autotensioner of the present invention, arranged as detailed above, has a structure which is easy to lubricate and free from fretting corrosion and which is therefore superior in terms of both durability and reliability, and yet enables the tension in the belt to be constantly maintained at an optimal level and thereby prevents the occurrence of problems such as an undesired shift in the mesh between the belt and the toothed pulleys (driving and driven pulleys).
Although the present invention has been described through specific terms, it should be noted that the described embodiments are not necessarily exclusive and that various changes and modifications may be imparted thereto without departing from the scope of the invention which is limited solely by the appended claims. | An autotensioner which is designed to apply appropriate tension to a timing belt of an engine or a belt that drives auxiliary machinery, for example, an alternator, compressor, etc. The autotensioner has an annular space that is partitioned into two chambers by a first partition wall which is provided on a fixed member and a second partition wall which is provided on a pivoting member, the annular space being filled with a viscous fluid. The first partition wall is formed with a passage which provides communication between the two chambers, and a check valve is provided in the passage. The check valve closes the passage when the tension in the belt increases suddenly, to resist the pivotal movement of the tensioner in one rotational direction, thereby enabling the tensioner to follow slowly and effectively the movement of the belt in which the tension is suddenly increased. The check valve opens the passage when the portion of the belt engaged by the tensioner becomes slack, thereby decreasing the resistance to movement of the second partition wall within the viscous fluid, thus enabling the tensioner to move rapidly in a rotational direction opposite the direction of movement of the tensioner when the tension in the belt increases. | 30,709 |
This application is a continuation of application Ser. No. 08/720,671, filed Oct. 2, 1996, now abandoned, which in turn is a continuation of application Ser. No. 08/467,189, filed Jun. 6, 1995, now abandoned, which in turn is a divisional application of application Ser. No. 08/360,944, filed Dec. 21, 1994, now U.S. Pat. No. 5,616,512.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a process for manufacturing integrated circuits, particularly of intelligent power semiconductor devices.
2. Discussion of the Related Art
In manufacturing integrated circuits, the problem of obtaining chip regions which are electrically insulated from one another exists. For example, in power semiconductor devices provided with on-chip driving circuitry (also called intelligent power semiconductor devices), the power device must be electrically insulated from the driving circuitry.
The most common technique to achieve this electrical insulation is PN junction isolation. However, this technique gives rise to some problems, especially related to the introduction of parasitic components.
Considering for example a Vertical Intelligent Power semiconductor device (VIP), such as an NPN power bipolar transistor constituted by an N++ emitter region diffused into a P-type base region which is in turn diffused into an N-type epitaxial layer representing the collector of the transistor. The driving circuitry is obtained inside a P-type well which is diffused into the N-type epitaxial layer and connected to the lowest voltage among those utilized in the chip to keep the P-type well/N-type epitaxial layer junction reverse biased. Inside the P-type well, vertical NPN transistors and lateral PNP transistors are generally obtained. In this structure, a number of parasitic bipolar transistors are present, both NPN and PNP, having base, emitter and collector represented by the various P-type or N-type regions inside the P-type well, the P-type well itself and the N-type epitaxial layer. Another PNP parasitic transistor has emitter, base and collector respectively represented by the P-type base region of the power transistor, the N-type epitaxial layer and the P-type well. All such parasitic components limit VIP performances.
SUMMARY OF THE INVENTION
In view of the state of art described, the object of the present invention is to develop a process for manufacturing integrated circuits, particularly for intelligent power semiconductor devices which creates devices wherein the electrical insulation between various semiconductor regions does not give rise to parasitic components.
According to the present invention, this object is attained by means of a process for manufacturing integrated circuits which includes the following steps.
An oxide layer is formed on at least one surface of two respective semiconductor material wafers to obtain a single semiconductor material wafer with a first layer and a second layer of semiconductor material and a buried oxide layer interposed therebetween starting from said two semiconductor material wafers by direct bonding of the oxide layers previously grown. The single wafer is exposed to a controlled reduction of the thickness of the first layer of semiconductor material, and then the top surface of the first layer of semiconductor material is lapped. Next dopant impurities are selectively introduced into selected regions of the first layer of semiconductor material to form the desired integrated components. An insulating material layer is then formed over the top surface of the first layer of semiconductor material. The insulating material layer, and the first layer of semiconductor material are selectively etched down to the buried oxide layer to form trenches laterally delimiting respective portions of the first layer of semiconductor material wherein integrated components are present which are to be electrically isolated from other integrated components. Finally, the walls of the trenches are coated with an insulating material and the trenches are filled with amorphous silicon
According to the present invention, it is possible to fabricate integrated circuits, particularly intelligent power semiconductor devices with an integrated driving circuitry, which are not affected by the presence of parasitic devices since the electrical isolation between the various devices is not accomplished by means of junction isolation, but by means of dielectric isolation.
If the integrated circuit to be fabricated is an intelligent power semiconductor device with an integrated driving circuitry, the process according to the invention comprises two additional steps.
The first semiconductor material layer is selectively etched down to the buried oxide layer to obtain selected portions of the single wafer wherein the buried oxide layer is uncovered, and dopant impurities are selectively introduced into selected regions of the second layer of semiconductor material to form the desired power device.
It is thus possible to fabricate intelligent power semiconductor devices with an integrated driving circuitry which are not affected by the presence of parasitic devices since the electrical isolation between the power devices and the driving circuitry and between the various components of the driving circuitry is not accomplished by means of junction isolation, but by means of dielectric isolation.
The features of the present invention will be made more evident by the following detailed description of its preferred embodiment, illustrated as a non-limiting example in the annexed drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 to 7 are cross-sectional views of a part of an integrated circuit taken at intermediate steps of a manufacturing process according to the preferred embodiment of the invention.
DETAILED DESCRIPTION
As shown in FIG. 1, a manufacturing process according to the invention starts from two distinct silicon wafers 1 and 2, generally doped with donor impurities. A first wafer 1 comprises an N-type semiconductor bulk 9 and an N+ heavily doped silicon layer 3 at its bottom surface The second wafer 2 has resistivity and thickness values depending on the particular power device that is to be obtained.
The two silicon wafers 1 and 2 are then submitted to a thermal oxidation process to grow on the bottom surface of the first wafer 1 and on the top surface of the second wafer 2 respective thermal oxide layers 5 and 6. During this step, thermal oxide layers 4 and 7 are also grown on the top surface of the first wafer 1 and the bottom surface of the second wafer 2, respectively.
The two wafers 1 and 2 are then bonded together by means of the so-called "Silicon Direct Bonding" (SDB) technique, known per se and described for example in the European Patent Application No. 89202692.3. After this step, a single silicon wafer is obtained from the two silicon wafers 1 and 2. The bottom oxide layer 5 of the first wafer 1 and the top oxide layer 6 of the second wafer 2 constitute a single oxide layer 8 sandwiched between the second wafer 2 and the N+ layer 3 of the first wafer 1, and thus, this oxide layer is buried under the first wafer 1 (FIG. 2). Among the various Silicon On Insulator (SOI) techniques, the SDB technique produces buried oxide layers of better quality.
The top oxide layer 4 of the first wafer 1 and the bottom oxide layer 7 of the second wafer 2 are then removed, and the N-type semiconductor bulk 9 of the first wafer 1 is submitted to a controlled reduction of its thickness. The top surface of the N-type semiconductor bulk 9 of the first wafer 1 is then polished by means of a precision lapping and polishing machine (with a thickness tolerance of about 0.1 mm). The top surface of N-type semiconductor bulk 9 of the first wafer 1, at the end of these steps, represents the top side of the single silicon wafer composed by the two bonded silicon wafers 1 and 2 (FIG. 3).
If the integrated device to be fabricated is a Vertical Intelligent Power (VIP) device, such as a bipolar power transistor, the N-type semiconductor bulk 9 and the N+ layer 3 of the first wafer 1 are selectively etched and removed down to the single oxide layer 8. At the end of this step, within all the regions 10 of the single silicon wafer wherein power devices are to be fabricated, the buried oxide layer 8 is uncovered. However, within all the regions 11 reserved to the driving circuitries for the power devices, the oxide layer 8 is still buried under the N-type semiconductor bulk 9 and the N+ layer 3 (FIG. 4). It is important to note that the etching angle a should be as small as possible, to avoid the creation of high steps so that the following depositions of the various layers (such as vapox, aluminum, nitride, etc.) is readily facilitated.
After this step, a thermal oxide layer is grown over the entire top surface of the wafer, i.e. over the top surface of the N-type silicon bulk 9 (in the wafer regions 11) and over the uncovered oxide layer 8 (in the wafer regions 10).
The power devices and their driving circuitries are fabricated in their respective wafer regions 10 and 11 according to a standard and per se known manufacturing process. It is to be noted that if the depth of field of the photolitographic apparatus employed in the manufacturing process is lower than the difference in height between the wafer regions 11 and 10, all the photolitographic steps in the wafer regions 10 reserved to the power devices are to be performed separately from those in the wafer regions 11 reserved to the driving circuitries.
FIG. 5 shows on an enlarged scale a part of a wafer region 11 wherein a vertical NPN transistor is present. As known to anyone skilled in the art, the transistor comprises a P-type base region 12 diffused into the N-type semiconductor bulk 9, and an N+ emitter region 13 diffused into said base region 12. The collector region is represented by a portion of the N-type semiconductor bulk 9 which is located under the emitter region 13. When the transistor is biased in the forward active region, electrons are injected from the emitter region 13 into the base region 12 wherefrom they diffuse into the collector region. The N+ layer 3 represents a buried layer offering a low resistive path for the electrons to an N+ collector contact region 14.
To electrically insulate the transistor shown in FIG. 5 from other integrated components defined in the same wafer region 11, the process according to the present invention provides for the realization of vertical trenches. To obtain said trenches, a per se known technique is used providing for the deposition over the top surface of the N-type silicon bulk 9 of an insulating material layer generally composed by three layers: a thin thermal oxide layer 15; a nitride layer 16 and a vapour-deposited oxide layer ("vapox") 17 (FIG. 5). Successively, the three layers 15, 16 and 17, together with the N-type semiconductor bulk 9 and the N+ layer 3, are selectively etched down to the buried oxide layer 8, to form a trench 18 around the lateral transistor shown as well as around all the other elements of the driving circuitry in the wafer region 11 which are to be electrically isolated from one another (FIG. 6).
The trench 18 must then be filled with an insulation material. According to the known technique, the walls of the trench 18 are first covered by an oxide layer 19, and the trench 18 is filled with amorphous silicon 20. In this way the wafer region 11 is divided into portions which are electrically insulated from one another laterally by means of the trench 18 and at the bottom by means of the buried oxide layer 8.
The top surface of the N-type silicon bulk 9 is then planarized, the three layers 15, 16 and 17 are removed from the surface of the N-type bulk 9, and a thermal oxide layer 21 is grown over the entire surface. Said oxide layer 21 is then selectively etched to form contact areas 22 (FIG. 7), and an aluminum layer (not shown) is deposited over the thermal oxide layer 21 and selectively etched to form the desired pattern of interconnection lines between the various components.
The process according to the present invention is suitable for the manufacturing of integrated circuits in general and not only of VIP devices. If no power devices are to be fabricated, neither the step of selective removal of the N-type semiconductor bulk 9 and of the N+ layer 3, nor the subsequent thermal oxidation of the entire wafer surface, are performed. Apart from these differences, the process is totally similar to that already described.
Having thus described one particular embodiment of the invention, various alterations, modifications and improvements will readily occur to those skilled in the art. Such alterations, modifications and improvements are intended to be part of this disclosure and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description is by way of example only, and not intended as limiting the invention is limited only as defined in the following claims and equivalents thereto. | Semiconductor device chips having a first layer of semiconductor material, a second layer of a semiconductor material and an insulating layer disposed therebetween. The first layer of semiconductor material has doped semiconductor regions disposed therein, and the second layer of semiconductor material has a power device disposed therein. The power device is disposed beneath the doped semiconductor region of the first layer. Trenches may be located within the first layer of semiconductor material to electrically isolate different areas having doped semiconductor regions. The insulating layer is typically formed from an oxide. | 13,346 |
CROSS-REFERENCE
[0001] This application claims the benefit of U.S. Provisional Application No. 61/175,397, filed May 4, 2009, which application is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] Diabetes mellitus is a disease characterized by elevated levels of plasma glucose. Uncontrolled hyperglycemia is associated with increased risk of vascular disease including, nephropathy, neuropathy, retinopathy, hypertension, and death. There are two major forms of diabetes. Type 1 diabetes (or insulin-dependent diabetes) and Type 2 diabetes (or noninsulin-dependent diabetes). The American Diabetes Association has estimated that approximately 6% of the world population has diabetes. The goal of diabetic therapy is to maintain a normal level of glucose in the blood. The American Diabetic Association has recommended that diabetics monitor their blood glucose level at least three times a day in order to adjust their insulin dosages and/or their eating habits and exercise regimen. While, glucose tests can only measure a point in time result and do not provide an overall assessment of glycemic control over a period of time, it is an important tool in diabetes care management.
[0003] Integrated cell phones with glucose testing capabilities have been developed. However, a significant drawback to these integrated devices is that they do not provide the opportunity to upgrade glucose hardware or meter functionality without replacing the entire phone. Moreover, if either the phone or glucose testing functionality is damaged, the entire device must be replaced to regain full functionality. In addition, for example, the iPhone® and iPod® Touch offer superior graphics and data display capability potential, along with the flexibility of unlimited applications to manage data and communications.
[0004] Other efforts to develop integrated treatment system with a glucose meter include, for example, insulin pump and wrist strap controller, as well as an effort to integrate the glucose meter and a cell phone. These integrated glucose meter/cellular phone combinations are under testing and currently cost $149.00 USD retail. Testing strips are proprietary and available only through the manufacturer without reimbursement by an insurance company. These “Glugophones” are currently offered in at least three forms: as a dongle for the iPhone, an add-on pack for LG model UX5000, VX5200, and LX350 cell phones, as well as an add-on pack for the Motorola Razr® cell phone. This further limits providers to AT&T for the iPhone and Verizon for the others. Similar systems have been tested for a longer time in Finland.
SUMMARY OF THE INVENTION
[0005] Module adaptable to communicate with a suitable handheld devices or PDAs. Suitable devices include, but are not limited to, the Apple iPhone® or iPod®, Research in Motion Blackberry® smart phones, Motorola Droid smart phones, and Palm Pre smart phones. The module can be used without adding to the cost of the handheld device. This allows direct reimbursement for the replaceable meter module portion if payers choose to limit coverage for the full system, as well as the possibility of reimbursement for the entire system including the handheld device. Other solutions build the cost into the phone, which must be replaced to upgrade or replace the glucose function. Moreover, information from the glucose meter reading can be communicated from the PDA to a remote station for reporting the results. With an iPod-like approach, this could be accomplished without the need for a cellular signal or carrier, as long as a WiFi internet connection is available anywhere in the world.
[0006] The glucose device described here is an attachment module using the standard connector interface of the handheld device. A single module could be used on multiple handheld devices, saving cost. This flexibility also means that the module could be used with a handheld device, such as an iPod, in the gym, or with a handheld device, such as an iPhone, in the office, etc. Since it is detachable, it does not require extra space or size in the handheld devices itself—it is only attached when a reading is required. It also does not add cost to the handheld device hardware, unlike the integrated units. The functionality of the module could range from a simple electronic interface to the strip (using the handheld device to do all calculations, data processing, display, and communications with health care providers or data services) to an interface plus glucose calculation engine (where the module delivers an answer, and the handheld device provides further data processing, display, and communications with health care providers or data services) to a fully contained meter with a small display, using the handheld device for much richer data processing, display, and communications.
[0007] An aspect of the disclosure is directed to an apparatus for use to determine blood glucose levels. The apparatus comprises: an aperture adapted and configured to receive a glucose test strip; a detector adapted and configured to detect at least one of a presence or amount of a substance indicative of glucose level; a connector adapted and configured to engage the first device; a power source; and one or more input buttons or touch screen controls wherein the apparatus further comprises a logic apparatus adapted and configured to read instructions from a computer readable storage media associated with at least one of a first device having connectable to the Internet and the apparatus, wherein the computer readable storage media is configured to tangibly store thereon computer readable instructions. Components, such as the logic apparatus and detector can be positioned within a suitable housing or can be configured to be engaged to functionally form a housing. The apparatus is typically handheld. A display screen adapted and configured to display at least one of instructions or measurement results can also be provided. A data processor can be adapted to determine a blood glucose value from a measurement.
[0008] Another aspect of the disclosure is directed to a method for detecting the blood glucose levels. The method comprises: obtaining a sample from a mammal; applying the sample to a test strip wherein the test strip is inserted into an aperture adapted and configured to receive the strip in an apparatus further comprising a detector adapted and configured to detect at least one of a presence or amount of a substance indicative of glucose level; a connector adapted and configured to engage the first device; a power source; and one or more input buttons or touch screen controls, wherein the apparatus further comprises a logic apparatus adapted and configured to read instructions from a computer readable storage media associated with at least one of a first device having connectable to the Internet and the apparatus, wherein the computer readable storage media is configured to tangibly store thereon computer readable instructions; and determining a glucose level from the sample; communicating the glucose level to a handheld apparatus in communication with the blood glucose apparatus. Additional method steps can include, for example, one or more of, instructing a device with mobile communication functionality to contact one or more of an emergency service agency, doctor, and caregiver; displaying results of a the blood glucose measurement; and storing the measurement results on a memory device.
[0009] Still another aspect of the disclosure is directed to a networked apparatus for determining blood glucose. The networked apparatus comprises: a memory; a processor; a communicator; a display; and an apparatus for detecting a blood glucose level comprising an aperture adapted and configured to receive a glucose test strip; a detector adapted and configured to detect at least one of a presence or amount of a substance indicative of glucose level; a connector adapted and configured to engage the first device; a power source; and one or more input buttons or touch screen controls, wherein the apparatus further comprises a logic apparatus adapted and configured to read instructions from a computer readable storage media associated with at least one of a first device having connectable to the Internet and the apparatus, wherein the computer readable storage media is configured to tangibly store thereon computer readable instructions.
[0010] Still another aspect is directed to communication system. The communication system comprises: an apparatus for detecting blood glucose level comprising an aperture adapted and configured to receive a glucose test strip; a detector adapted and configured to detect at least one of a presence or amount of a substance indicative of glucose level; a connector adapted and configured to engage the first device; a power source; and one or more input buttons or touch screen controls, wherein the apparatus further comprises a logic apparatus adapted and configured to read instructions from a computer readable storage media associated with at least one of a first device having connectable to the Internet and the apparatus, wherein the computer readable storage media is configured to tangibly store thereon computer readable instructions; a server computer system; a measurement module on the server computer system for permitting the transmission of a measurement from a system for detecting blood glucose levels over a network; at least one of an API engine connected to at least one of the system for detecting blood glucose levels and the device for detecting blood glucose levels to create an message about the measurement and transmit the message over an API integrated network to a recipient having a predetermined recipient user name, an SMS engine connected to at least one of the system for detecting blood glucose levels and the device for detecting blood glucose levels to create an SMS message about the measurement and transmit the SMS message over a network to a recipient device having a predetermined measurement recipient telephone number, and an email engine connected to at least one of the system for detecting blood glucose levels and the device for detecting blood glucose levels to create an email message about the measurement and transmit the email message over the network to a recipient email having a predetermined recipient email address. Additionally, the system can further comprise a storing module on the server computer system for storing the measurement on the system for detecting blood glucose levels server database. In some configurations at least one of the system for detecting blood glucose levels and the device for detecting blood glucose levels is connectable to the server computer system over at least one of a mobile phone network and an Internet network, and a browser on the measurement recipient electronic device is used to retrieve an interface on the server computer system. Additionally, a plurality of email addresses can be held in a system for detecting blood glucose levels database and fewer than all the email addresses are individually selectable from the diagnostic host computer system, the email message being transmitted to at least one recipient email having at least one selected email address. wherein at least one of the system for detecting blood glucose levels and the device for detecting blood glucose levels is connectable to the server computer system over the Internet, and a browser on the measurement recipient electronic device is used to retrieve an interface on the server computer system. A plurality of user names can be held in the system for detecting blood glucose levels database and fewer than all the user names are individually selectable from the diagnostic host computer system, the message being transmitted to at least one measurement recipient user name via an API. Additionally, measurement recipient electronic device (e.g., smart phone, computer or glucose measurement device) is connectable directly or indirectly to the server computer system over the Internet, and a browser on the measurement recipient electronic device is used to retrieve an interface on the server computer system. Typically, the measurement recipient electronic device is connected to the server computer system over a cellular phone network. In many cases, the measurement recipient electronic device is a mobile device. An interface can also be provided on the server computer system, the interface being retrievable by an application on the mobile device. An SMS message is received by a message application on the mobile device. In some instances, a plurality of SMS messages are received for the measurement, each by a respective message application on a respective recipient mobile device. Typically, at least one SMS engine receives an SMS response over the cellular phone SMS network from the mobile device and stores an SMS response on the server computer system. Additionally, the measurement recipient phone number ID is transmitted with the SMS message to the SMS engine and is used by the server computer system to associate the SMS message with the SMS response. The server computer system can be configured to be connectable over a cellular phone network to receive a response from the measurement recipient mobile device. Additionally, the SMS message can include a URL that is selectable at the measurement recipient mobile device to respond from the measurement recipient mobile device to the server computer system, the server computer system utilizing the URL to associate the response with the SMS message. In some configurations, the system can further comprise, a downloadable application residing on the measurement recipient mobile device, the downloadable application transmitting the response and a measurement recipient phone number ID over the cellular phone network to the server computer system, the server computer system utilizing the measurement recipient phone number ID to associate the response with the SMS message; a transmissions module that transmits the measurement over a network other than the cellular phone SMS network to a measurement recipient user computer system, in parallel with the measurement that is sent over the cellular phone SMS network; and/or a downloadable application residing on the measurement recipient host computer, the downloadable application transmitting a response and a measurement recipient phone number ID over the cellular phone network to the server computer system, the server computer system utilizing the measurement recipient phone number ID to associate the response with the SMS message.
[0011] Another aspect of the disclosure is directed to a networked apparatus. The networked apparatus comprises: a memory; a processor; a communicator; a display; and an aperture adapted and configured to receive a glucose test strip; a detector adapted and configured to detect at least one of a presence or amount of a substance indicative of glucose level; a connector adapted and configured to engage the first device; a power source; and one or more input buttons or touch screen controls, wherein the apparatus further comprises a logic apparatus adapted and configured to read instructions from a computer readable storage media associated with at least one of a first device having connectable to the Internet and the apparatus, wherein the computer readable storage media is configured to tangibly store thereon computer readable instructions.
[0012] Still another aspect of the disclosure is directed to a communication system. The communication system comprises: an apparatus for detecting blood glucose level comprising an aperture adapted and configured to receive a glucose test strip; a detector adapted and configured to detect at least one of a presence or amount of a substance indicative of glucose level; a connector adapted and configured to engage the first device; a power source; and one or more input buttons or touch screen controls, wherein the apparatus further comprises a logic apparatus adapted and configured to read instructions from a computer readable storage media associated with at least one of a first device having connectable to the Internet and the apparatus, wherein the computer readable storage media is configured to tangibly store thereon computer readable instructions; a server computer system; a measurement module on the server computer system for permitting the transmission of a measurement from a system for detecting blood glucose levels over a network; at least one of an API engine connected to at least one of the system for detecting blood glucose levels and the device for detecting blood glucose levels to create an message about the measurement and transmit the message over an API integrated network to a recipient having a predetermined recipient user name, an SMS engine connected to at least one of the system for detecting blood glucose levels and the device for detecting blood glucose levels to create an SMS message about the measurement and transmit the SMS message over a network to a recipient device having a predetermined measurement recipient telephone number, and an email engine connected to at least one of the system for detecting blood glucose levels and the device for detecting blood glucose levels to create an email message about the measurement and transmit the email message over the network to a recipient email having a predetermined recipient email address. A storing module can also be provided on the server computer system for storing the measurement on the system for detecting blood glucose levels server database. In some configurations at least one of the system for detecting blood glucose levels and the device for detecting blood glucose levels is connectable to the server computer system over at least one of a mobile phone network and an Internet network, and a browser on the measurement recipient electronic device is used to retrieve an interface on the server computer system. Additionally, a plurality of email addresses are held in a system for detecting blood glucose levels database and fewer than all the email addresses are individually selectable from the diagnostic host computer system, the email message being transmitted to at least one recipient email having at least one selected email address. In some configurations, at least one of the system for detecting blood glucose levels and the device for detecting blood glucose levels is connectable to the server computer system over the Internet, and a browser on the measurement recipient electronic device is used to retrieve an interface on the server computer system. A plurality of user names can be held in the system for detecting blood glucose levels database and fewer than all the user names are individually selectable from the diagnostic host computer system, the message being transmitted to at least one measurement recipient user name via an API. Moreover, the measurement recipient electronic device is connectable to the server computer system over the Internet, and a browser on the measurement recipient electronic device is used to retrieve an interface on the server computer system. The measurement recipient electronic device can be connected to the server computer system over a cellular phone network, such as where the measurement recipient electronic device is a mobile device. Additionally, an interface on the server computer system, the interface being retrievable by an application on the mobile device. The SMS message can be received by a message application on the mobile device and, in at least some instances, a plurality of SMS messages are received for the measurement, each by a respective message application on a respective recipient mobile device. At least one SMS engine can be configured to receive an SMS response over the cellular phone SMS network from the mobile device and stores an SMS response on the server computer system. A measurement recipient phone number ID is transmitted with the SMS message to the SMS engine and is used by the server computer system to associate the SMS message with the SMS response. A server computer system is connectable over a cellular phone network to receive a response from the measurement recipient mobile device. The SMS message can includes, for example, a URL that is selectable at the measurement recipient mobile device to respond from the measurement recipient mobile device to the server computer system, the server computer system utilizing the URL to associate the response with the SMS message. The system can further include a downloadable application residing on the measurement recipient mobile device, the downloadable application transmitting the response and a measurement recipient phone number ID over the cellular phone network to the server computer system, the server computer system utilizing the measurement recipient phone number ID to associate the response with the SMS message; a transmissions module that transmits the measurement over a network other than the cellular phone SMS network to a measurement recipient user computer system, in parallel with the measurement that is sent over the cellular phone SMS network; a downloadable application residing on the measurement recipient host computer, the downloadable application transmitting a response and a measurement recipient phone number ID over the cellular phone network to the server computer system, the server computer system utilizing the measurement recipient phone number ID to associate the response with the SMS message.
INCORPORATION BY REFERENCE
[0013] All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, or patent application was specifically and individually indicated to be incorporated by reference.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] The novel features of the invention are set forth with particularity in the appended claims. A better understanding of the features and advantages of the present invention will be obtained by reference to the following detailed description that sets forth illustrative embodiments, in which the principles of the invention are utilized, and the accompanying drawings of which:
[0015] FIG. 1A is a perspective view of a handheld device suitable for use with the invention;
[0016] FIG. 1B is a depiction of a testing strip suitable for glucose testing;
[0017] FIG. 2A is a depiction of a handheld device in communication with an attachable glucose monitor;
[0018] FIG. 2B is a depiction of a handheld device in communication with an attachable glucose monitor wherein the monitor has a read-out screen;
[0019] FIGS. 3A-B are schematic block diagrams of devices for diabetes monitoring;
[0020] FIG. 4 is a flow chart illustrating method steps; and
[0021] FIG. 5A is a block diagram showing a representative example of a logic device through which a dynamic modular and scalable system can be achieved; and
[0022] FIG. 5B is a block diagram showing the cooperation of exemplary components of a system suitable for use in a system where dynamic data analysis and modeling is achieved.
DETAILED DESCRIPTION OF THE INVENTION
[0023] Currently there is no way for a handheld device to directly interface with a blood glucose meter thereby providing the potential for a rich data processing, display, and communications capabilities of the handheld device (e.g., iPhone and iPod Touch). These configurations provide the advantage of: flexibility of functionality and reimbursement coverage; ability for module provider to upgrade module over time without user having to upgrade phone; ability for any diabetes company to develop a module to work with the handheld device. These benefits also limit the cost of phone hardware and provide limited capability to develop and use future applications.
[0024] The present invention relates to glucose monitoring systems and methods, and more particularly to a system that adapts to engage a handheld device and which is configured to monitor the amount and rate of change of glucose in a patient, communicating the results to an easy-to-read display of such monitored information.
I. DEVICE PLATFORM/INTERFACE
[0025] FIG. 1 a illustrates a suitable smart phone device or handheld device 100 suitable for use in the system described. The handheld device 100 has a touch screen 102 and ports 104 suitable for use as, for example, data import and export, and buttons 106 . However, as will be appreciated by those in skill in the art, a device which provides a keyboard could also be used without departing from the scope of the invention. FIG. 1 b illustrates a standard glucose test strip 110 , such as those currently available from J&J and Abbot Diabetes Care.
[0026] A standard connector interface adapted to communicate with the handheld device 100 , such as a iPhone/iPod dock connector can be used to achieve communication of information between the handheld device and, for example, a measurement device or other peripheral device.
[0027] As illustrated in FIGS. 2 a and 2 b, the handheld device 200 is adapted and configured to engage the glucose measurement device 220 . The handheld device and glucose measurement device connection can be wireless (e.g., Blue Tooth), or wired. The device 200 is illustrated to include a touch screen 202 , ports, 204 , and buttons 206 . A test strip 210 is inserted into an aperture or channel configured to receive the strip. An aperture for receiving the test strip could, for example, be positioned on the glucose meter from a side of the measurement device that does not engage the handheld device, as illustrated in FIGS. 2 . In the configuration shown in FIG. 2 b, a display 222 is also provided. The test strip 210 typically contains a chemical for detecting glucose, such as glucose oxidase. This chemical reacts with the glucose in the blood sample provided by the user to create gluconic acid. Gluconic acid then reacts with, for example, ferricyanide, to create ferrocyanide. Once the ferrocyanide is created, the measurement device 220 runs an electronic current through the blood sample on the strip 210 . This current is then able to detect the ferrocyanide and determine how much glucose is in the sample of blood on the test strip 210 . That number is then relayed on the screen of the measurement device or on the handheld device connected to the measurement device.
[0028] FIG. 3A-B is an illustration of a measurement device 320 . A power source 330 , which may be removable, adapted and configured to provide power to the system, is shown. The power source 330 can be removable, rechargeable, or fixed (as in the case of a power cord). Suitable power sources include, but are not limited to, batteries. The power source 330 may be activated by a control button 334 . Moreover, power can come from an auxiliary device that the measurement device is connected to such as a computer or mobile phone. Additionally, a microcontroller can be provided on the device in order to facilitated manipulation and analysis of the information obtained from the sample. Alternatively, the information can be transmitted to a secondary device for manipulation.
[0029] An electromagnetic data storage device 336 (such as ROM, RAM, digital data storage, etc., such as in devices where data processing is provided) can be provided which stores instructions for operation of the measurement device. A memory, flash memory, and/or a full chip set or integrated circuit can be provided that interfaces (such as universal serial bus (USB) with the device. For the purposes of this disclosure a computer readable medium stores computer data, which data can include computer program code that is executable by a computer, in machine readable form. Computer readable medium may comprise computer readable storage media, for tangible or fixed storage of data, or communication media for transient interpretation of code-containing signals. Computer readable storage media includes physical or tangible storage (as opposed to signals) and includes without limitation volatile and non-volatile, removable and non-removable storage media implemented in any method or technology for the tangible storage of information such as computer-readable instructions, data structures, program modules or other data. Computer readable storage media includes, but is not limited to, RAM, ROM, EPROM, EEPROM, flash memory or other solid state memory technology, CD-ROM, DVD, or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other physical or material medium which can be used to tangibly store the desired information or data or instructions and which can be accessed by a computer or processor.
[0030] A port or channel 340 is provided for interfacing with the test strip (shown above). Additionally, input buttons 338 can be provided that enable a user to input information into the device itself. In some configurations a display 350 is provided. Suitable displays include, for example, liquid crystal displays (LCD).
[0031] As will be appreciated by those skilled in the art, the system can be contained within a suitably designed housing 332 or the components can be configured such that the components are interconnected in such a way as to function as a housing. A channel or port 340 is provided which is adaptable and configurable to receive a commercially available glucose test strip (shown in FIG. 2 ). A blood sample placed in fluid communication with the test strip which then determines the amount of ferrocyanide by measuring an electrical current.
[0032] As will be appreciated by those skilled in the art, connectivity can also be provided which enables the system to send the information to a printer, or a network. Connectivity can be, for example, wirelessly via the internet as well as via suitable connection ports.
II. GLUCOSE MEASUREMENTS
[0033] Electrochemical glucose monitors consist of a disposable sensor strip ( 110 , in FIG. 1 ) that is made with multiple layers of conductive and reactive components, including enzymes to catalyze the reaction of the blood glucose in proximity to electrodes which capture and carry the generated current through conductors to the measurement electronics. Examples include, but are not limited to LifeScan's OneTouch Ultra® series, or Abbott's Therasense FreeStyle® series, or Roche's Accu-Chek®. FIG. 2 illustrates the OneTouch Ultra ® sensor strip, with 3 electrical contact connections on the left and blood application capillary on the right.
[0034] The module adaptor is adapted for measuring blood glucose values and for generating blood glucose data in response to measuring said blood glucose values. As discussed more fully below, the module adaptor can be configured such that it is connected to a glucose measuring apparatus. Moreover, the monitor can be adapted and configured such that it is capable of receiving, storing and evaluating data. Examples include: (a) receiving and storing blood glucose data, (b) receiving and storing physician-supplied data, (c) prompting and receiving patient input into the monitor means at periodic times of patient data relating to diet, exercise, emotional stress and symptoms of hypoglycemia and other illness experienced by the patient during a preceding time period, (d) receiving and storing the patient data supplied by the patient, and (e) generating recommendations relative to patient insulin dosage based at least in part upon the received blood glucose data, physician data and patient data.
III. METHODS
[0035] Typical Use Steps are illustrated in FIG. 4 : Typical use steps include connecting a glucose measurement device to handheld device 410 , e.g., through standard dock interface, a cable, or Blue Tooth connection; once the two devices are in communication, the adaptor of the invention powers-up 420 , confirms ready to insert strip; instructions may then be provided to apply blood to the test strip; thereafter the device measures glucose from the sample 430 by automatically starting, and counts down to result; reports result 440 , either on handheld device 450 or the measurement device, and/or instructing the device to call emergency services 460 (e.g., 911) where the sugar level is below a pre-set or patient-specific pre-determined threshold, and/or storing the data 470 on either the measurement device or the handheld device to which the measurement device is attached.
[0036] The handheld device can then be used to chart data, graph data, sort and trend data for specifics like “pre-breakfast” etc. (standard and new custom applications are possible); handheld device can transmit sets of data to diabetes professionals for further analysis or advice. Moreover, parameters can be set for the device where transmission of data occurs when, for example, a reading exceeds a certain blood glucose threshold; a series of readings exceeds an blood glucose trend, etc. Where a patient takes a blood reading and the blood glucose level is dangerously low —thus resulting in the patient being confused and unable to make a call for emergency assistance—the device could call 911 and provide a message that the patient has a dangerously low blood glucose level and may not be able to stabilize without professional intervention.
IV. GLUCOSE MOBILE ADAPTOR DEVICES AND COMMUNICATION NETWORKS
[0037] As will be appreciated by those skilled in the art, modular and scalable system employing one or more of the glucose measurement devices discussed above can be provided which comprises a controller and more than one glucose measurement devices. Controller communicates with each glucose measurement device over a communication media. Communication media may be a wired point-to-point or multi-drop configuration. Examples of wired communication media include Ethernet, USB, and RS-232. Alternatively communication media may be wireless including radio frequency (RF) and optical. The glucose measurement device may have one or more slots for fluid processing devices such as test strips discussed above. Networked devices can be particularly useful in some situations. For example, networked devices that provide blood glucose monitoring results to a care provider (such as a doctor) can facilitate background analysis of compliance of a diabetic with diet, medication and insulin regimes which could then trigger earlier intervention by a healthcare provider when results begin trending in a clinically undesirable direction. Additionally, automatic messages in response to sample measurements can be generated to either the patient monitoring their glucose level and/or to the care provider. In some instances, automatic messages may be generated by the system to either encourage behavior (e.g., a text message or email indicating a patient is on track) or discourage behavior (e.g., a text message or email indicating that sugars are trending upward). Other automated messages could be either email or text messages providing pointers and tips for managing blood sugar. The networked communication system therefore enables background health monitoring and early intervention which can be achieved at a low cost with the least burden to health care practitioners. Additionally, live chat or texting can be facilitated via the mobile device to enable a care provider to intervene with a user real time in response to a recent communication. The user can easily review the results on the glucose measurement device while communicating with the care giver, or other person, on the wireless communication device.
[0038] To further appreciate the networked configurations of multiple glucose measurement device in a communication network, FIG. 5A is a block diagram showing a representative example logic device through which a browser can be accessed to control and/or communication with glucose measurement device described above. A computer system (or digital device) 500 , which may be understood as a logic apparatus adapted and configured to read instructions from computer readable storage media 514 which is configured to tangibly store thereon computer readable instructions and/or network port 506 , is connectable to a server 510 , and has a fixed media 516 . The computer system 500 can also be connected to the Internet or an intranet. The system includes central processing unit (CPU) 502 , disk drives 504 , optional input devices, illustrated as keyboard 518 and/or mouse 520 and optional monitor 508 . Data communication can be achieved through, for example, communication medium 509 to a server 510 at a local or a remote location. The communication medium 509 can include any suitable means or mechanism of transmitting and/or receiving data. For example, the communication medium can be a network connection, a wireless connection, or an internet connection. It is envisioned that data relating to the use, operation or function of the one or more glucose measurement devices (shown together for purposes of illustration here as 560 ) can be transmitted over such networks or connections. The computer system can be adapted to communicate with a user (users include healthcare providers, physicians, lab technicians, nurses, nurse practitioners, patients, and any other person or entity which would have access to information generated by the system) and/or a device used by a user. The computer system is adaptable to communicate with other computers over the Internet, or with computers via a server. Moreover the system is configurable to activate one or more devices associated with the network (e.g., diagnostic devices and/or glucose measurement device) and to communicate status and/or results of tests performed by the devices and/or systems.
[0039] As is well understood by those skilled in the art, the Internet is a worldwide network of computer networks. Today, the Internet is a public and self-sustaining network that is available to many millions of users. The Internet uses a set of communication protocols called TCP/IP (i.e., Transmission Control Protocol/Internet Protocol) to connect hosts. The Internet has a communications infrastructure known as the Internet backbone. Access to the Internet backbone is largely controlled by Internet Service Providers (ISPs) that resell access to corporations and individuals.
[0040] The Internet Protocol (IP) enables data to be sent from one device (e.g., a phone, a Personal Digital Assistant (PDA), a computer, etc.) to another device on a network. There are a variety of versions of IP today, including, e.g., IPv4, IPv6, etc. Other IPs are no doubt available and will continue to become available in the future, any of which can, in a communication network adapted and configured to employ or communicate with one or more glucose measurement devices, be used without departing from the scope of the disclosure. Each host device on the network has at least one IP address that is its own unique identifier and acts as a connectionless protocol. The connection between end points during a communication is not continuous. When a user sends or receives data or messages, the data or messages are divided into components known as packets. Every packet is treated as an independent unit of data and routed to its final destination—but not necessarily via the same path.
[0041] The Open System Interconnection (OSI) model was established to standardize transmission between points over the Internet or other networks. The OSI model separates the communications processes between two points in a network into seven stacked layers, with each layer adding its own set of functions. Each device handles a message so that there is a downward flow through each layer at a sending end point and an upward flow through the layers at a receiving end point. The programming and/or hardware that provides the seven layers of function is typically a combination of device operating systems, application software, TCP/IP and/or other transport and network protocols, and other software and hardware.
[0042] Typically, the top four layers are used when a message passes from or to a user and the bottom three layers are used when a message passes through a device (e.g., an IP host device). An IP host is any device on the network that is capable of transmitting and receiving IP packets, such as a server, a router or a workstation. Messages destined for some other host are not passed up to the upper layers but are forwarded to the other host. The layers of the OSI model are listed below. Layer 7 (i.e., the application layer) is a layer at which, e.g., communication partners are identified, quality of service is identified, user authentication and privacy are considered, constraints on data syntax are identified, etc. Layer 6 (i.e., the presentation layer) is a layer that, e.g., converts incoming and outgoing data from one presentation format to another, etc. Layer 5 (i.e., the session layer) is a layer that, e.g., sets up, coordinates, and terminates conversations, exchanges and dialogs between the applications, etc. Layer- 4 (i.e., the transport layer) is a layer that, e.g., manages end-to-end control and error-checking, etc. Layer- 3 (i.e., the network layer) is a layer that, e.g., handles routing and forwarding, etc. Layer- 2 (i.e., the data-link layer) is a layer that, e.g., provides synchronization for the physical level, does bit-stuffing and furnishes transmission protocol knowledge and management, etc. The Institute of Electrical and Electronics Engineers (IEEE) sub-divides the data-link layer into two further sub-layers, the MAC (Media Access Control) layer that controls the data transfer to and from the physical layer and the LLC (Logical Link Control) layer that interfaces with the network layer and interprets commands and performs error recovery. Layer 1 (i.e., the physical layer) is a layer that, e.g., conveys the bit stream through the network at the physical level. The IEEE sub-divides the physical layer into the PLCP (Physical Layer Convergence Procedure) sub-layer and the PMD (Physical Medium Dependent) sub-layer.
[0043] Wireless networks can incorporate a variety of types of mobile devices, such as, e.g., cellular and wireless telephones, PCs (personal computers), laptop computers, tablet computers, wearable computers, cordless phones, pagers, headsets, printers, PDAs, etc. and suitable for use in a system or communication network that includes one or more glucose measurement devices. For example, mobile devices may include digital systems to secure fast wireless transmissions of voice and/or data. Typical mobile devices include some or all of the following components: a transceiver (for example a transmitter and a receiver, including a single chip transceiver with an integrated transmitter, receiver and, if desired, other functions); an antenna; a processor; display; one or more audio transducers (for example, a speaker or a microphone as in devices for audio communications); electromagnetic data storage (such as ROM, RAM, digital data storage, etc., such as in devices where data processing is provided); memory; flash memory; and/or a full chip set or integrated circuit; interfaces (such as universal serial bus (USB), coder-decoder (CODEC), universal asynchronous receiver-transmitter (UART), phase-change memory (PCM), etc.). Other components can be provided without departing from the scope of the disclosure.
[0044] Wireless LANs (WLANs) in which a mobile user can connect to a local area network (LAN) through a wireless connection may be employed for wireless communications between one or more glucose measurement devices. Wireless communications can include communications that propagate via electromagnetic waves, such as light, infrared, radio, and microwave. There are a variety of WLAN standards that currently exist, such as Bluetooth®, IEEE 802.11, and the obsolete HomeRF.
[0045] By way of example, Bluetooth products may be used to provide links between mobile computers, mobile phones, portable handheld devices, personal digital assistants (PDAs), and other mobile devices and connectivity to the Internet. Bluetooth is a computing and telecommunications industry specification that details how mobile devices can easily interconnect with each other and with non-mobile devices using a short-range wireless connection. Bluetooth creates a digital wireless protocol to address end-user problems arising from the proliferation of various mobile devices that need to keep data synchronized and consistent from one device to another, thereby allowing equipment from different vendors to work seamlessly together.
[0046] An IEEE standard, IEEE 802.11, specifies technologies for wireless LANs and devices. Using 802.11, wireless networking may be accomplished with each single base station supporting several devices. In some examples, devices may come pre-equipped with wireless hardware or a user may install a separate piece of hardware, such as a card, that may include an antenna. By way of example, devices used in 802.11 typically include three notable elements, whether or not the device is an access point (AP), a mobile station (STA), a bridge, a personal computing memory card International Association (PCMCIA) card (or PC card) or another device: a radio transceiver; an antenna; and a MAC (Media Access Control) layer that controls packet flow between points in a network.
[0047] In addition, Multiple Interface Devices (MIDs) may be utilized in some wireless networks. MIDs may contain two independent network interfaces, such as a Bluetooth interface and an 802.11 interface, thus allowing the MID to participate on two separate networks as well as to interface with Bluetooth devices. The MID may have an IP address and a common IP (network) name associated with the IP address.
[0048] Wireless network devices may include, but are not limited to Bluetooth devices, WiMAX (Worldwide Interoperability for Microwave Access), Multiple Interface Devices (MIDs), 802.11x devices (IEEE 802.11 devices including, 802.11a, 802.11b and 802.11g devices), HomeRF (Home Radio Frequency) devices, Wi-Fi (Wireless Fidelity) devices, GPRS (General Packet Radio Service) devices, 3 G cellular devices, 2.5 G cellular devices, GSM (Global System for Mobile Communications) devices, EDGE (Enhanced Data for GSM Evolution) devices, TDMA type (Time Division Multiple Access) devices, or CDMA type (Code Division Multiple Access) devices, including CDMA2000. Each network device may contain addresses of varying types including but not limited to an IP address, a Bluetooth Device Address, a Bluetooth Common Name, a Bluetooth IP address, a Bluetooth IP Common Name, an 802.11 IP Address, an 802.11 IP common Name, or an IEEE MAC address.
[0049] Wireless networks can also involve methods and protocols found in, Mobile IP (Internet Protocol) systems, in PCS systems, and in other mobile network systems. With respect to Mobile IP, this involves a standard communications protocol created by the Internet Engineering Task Force (IETF). With Mobile IP, mobile device users can move across networks while maintaining their IP Address assigned once. See Request for Comments (RFC) 3344. NB: RFCs are formal documents of the Internet Engineering Task Force (IETF). Mobile IP enhances Internet Protocol (IP) and adds a mechanism to forward Internet traffic to mobile devices when connecting outside their home network. Mobile IP assigns each mobile node a home address on its home network and a care-of-address (CoA) that identifies the current location of the device within a network and its subnets. When a device is moved to a different network, it receives a new care-of address. A mobility agent on the home network can associate each home address with its care-of address. The mobile node can send the home agent a binding update each time it changes its care-of address using Internet Control Message Protocol (ICMP).
[0050] In basic IP routing (e.g., outside mobile IP), routing mechanisms rely on the assumptions that each network node always has a constant attachment point to the Internet and that each node's IP address identifies the network link it is attached to. Nodes include a connection point, which can include a redistribution point or an end point for data transmissions, and which can recognize, process and/or forward communications to other nodes. For example, Internet routers can look at an IP address prefix or the like identifying a device's network. Then, at a network level, routers can look at a set of bits identifying a particular subnet. Then, at a subnet level, routers can look at a set of bits identifying a particular device. With typical mobile IP communications, if a user disconnects a mobile device from the Internet and tries to reconnect it at a new subnet, then the device has to be reconfigured with a new IP address, a proper netmask and a default router. Otherwise, routing protocols would not be able to deliver the packets properly.
[0051] Computing system 500 , described above, can be deployed as part of a computer network that includes one or devices 560 , such as glucose measurement devices disclosed herein. In general, the description for computing environments applies to both server computers and client computers deployed in a network environment. FIG. 5B illustrates an exemplary illustrative networked computing environment 500 , with a server in communication with client computers via a communications network 550 . As shown in FIG. 5B , server 510 may be interconnected via a communications network 550 (which may be either of, or a combination of a fixed-wire or wireless LAN, WAN, intranet, extranet, peer-to-peer network, virtual private network, the Internet, or other communications network) with a number of client computing environments such as tablet personal computer 502 , mobile telephone 504 , telephone 506 , personal computer 502 ′, and personal digital assistant 508 . In a network environment in which the communications network 550 is the Internet, for example, server 510 can be dedicated computing environment servers operable to process and communicate data to and from client computing environments via any of a number of known protocols, such as, hypertext transfer protocol (HTTP), file transfer protocol (FTP), simple object access protocol (SOAP), or wireless application protocol (WAP). Other wireless protocols can be used without departing from the scope of the disclosure, including, for example Wireless Markup Language (WML), DoCoMo i-mode (used, for example, in Japan) and XHTML Basic. Additionally, networked computing environment 500 can utilize various data security protocols such as secured socket layer (SSL) or pretty good privacy (PGP). Each client computing environment can be equipped with operating system 538 operable to support one or more computing applications, such as a web browser (not shown), or other graphical user interface (not shown), or a mobile desktop environment (not shown) to gain access to server computing environment 500 .
[0052] In operation, a user (not shown) may interact with a computing application running on a client computing environment to obtain desired data and/or computing applications. The data and/or computing applications may be stored on server computing environment 500 and communicated to cooperating users through client computing environments over exemplary communications network 550 . A participating user may request access to specific data and applications housed in whole or in part on server computing environment 500 . These data may be communicated between client computing environments and server computing environments for processing and storage. Server computing environment 500 may host computing applications, processes and applets for the generation, authentication, encryption, and communication data and applications and may cooperate with other server computing environments (not shown), third party service providers (not shown), network attached storage (NAS) and storage area networks (SAN) to realize application/data transactions.
[0053] V. KITS
[0054] Bundling all devices, tools, components, materials, and accessories needed to use a measurement device to test a sample into a kit may enhance the usability and convenience of the devices. Suitable kits for glucose measurement can also include, for example, power source; test strips; wireless communication apparatus; and a glucose measurement device.
VI. EXAMPLES
Example 1
[0055] In some configurations, the module adaptor can be configured to connect to standard 3 conductor (or two, or more) electrochemical glucose sensor strip, and simply passes the connection through the interface with minimal circuitry or processing. The handheld device connected to the module electronically monitors the signal, and the glucose application within the handheld device contains the glucose calculation engine to convert the measured voltages/currents into a blood glucose result. The adaptor could be self powered by a rechargeable battery (e.g., from its handheld device connection) or replaceable internal battery, or could simply derive power solely off handheld device connection power.
Example 2
[0056] In some configurations, the adapter or module itself can be configured to contain circuitry and software to power and monitor a sensor strip, and to calculate a glucose result internally before transferring this result to the handheld device. This offers some advantages in terms of completely controlling the glucose calculation, to help ensure that future changes to the handheld device or their glucose applications will not interfere with calculating a correct glucose result as detected by the adapter. Such a configuration could be configured such that it is powered by rechargeable or replaceable battery, or, as described above, off the handheld device. Moreover, permanent memory resident to the adapter could be configured to include firmware.
Example 3
[0057] In other configurations, the adaptor or module is configured to calculate glucose values internally as described above for Example 2. Additionally, the adaptor can be configured to provide a small or simple display screen that can be used to compare/confirm the result as reported by handheld device. Also has the advantage of being a tiny stand-alone meter that can be used either attached or detached from the handheld device. For detachable use, the device would be configured to include a rechargeable or replaceable battery. However, it could also be powered off of the handheld device when it is in an attached configuration. Memory can also be provided for storing one or multiple glucose results. Stored results can then be uploaded to the handheld device in a separate step when the device is connected to a handheld device. In most configurations, the handheld device is capable of any level of complexity in glucose data reporting and storage, including simply reporting the current result in large, easy to read format, storing multiple results for later review, graphing, and otherwise trending and reporting results, and transmitting any or all of these and more to a central service or physician.
[0058] Advantages of the adapter include flexibility. As new applications come out, new data management features can be introduced. Unlike current fully integrated glucose monitoring cell phones, the adaptor module is detachable, transferable, and replaceable without purchasing a new handheld device.
[0059] While preferred embodiments of the present invention have been shown and described herein, it will be obvious to those skilled in the art that such embodiments are provided by way of example only. Numerous variations, changes, and substitutions will now occur to those skilled in the art without departing from the invention. It should be understood that various alternatives to the embodiments of the invention described herein may be employed in practicing the invention. It is intended that the following claims define the scope of the invention and that methods and structures within the scope of these claims and their equivalents be covered thereby. | Module adaptable to communicate with a suitable handheld devices or PDAs. Suitable devices include, but are not limited to, the Apple iPhone® or iPod®, Research in Motion Blackberry® smart phones, Motorola Droid smart phones, and Palm Pre smart phones. The module can be used without adding to the cost of the handheld device. This allows direct reimbursement for the replaceable meter module portion if payers choose to limit coverage for the full system, as well as the possibility of reimbursement for the entire system including the handheld device. Other solutions build the cost into the phone, which must be replaced to upgrade or replace the glucose function. Moreover, information from the glucose meter reading can be communicated from the PDA to a remote station for reporting the results. With an iPod-like approach, this could be accomplished without the need for a cellular signal or carrier, as long as a WiFi internet connection is available anywhere in the world. | 57,526 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to fabrication of an optical fiber preform. More specifically, the present invention relates to removing soot particles and controlling the diameter of the preform during a chemical vapor deposition (CVD) process.
[0003] 2. Description of the Related Art
[0004] The present invention is useable with a process for manufacturing a preform from which optical fibers may be drawn. Such optical fibers are used for transmitting optical signals in telecommunications applications. The preform may be manufactured by a variety of methods, including the CVD process in which glassy particles (soot) are deposited onto the inside wall of a glass substrate tube. The soot generally comprises silica that has been doped to provide a desired index of refraction. During the deposition process the soot is passed longitudinally through the glass tube by a carrier gas and a heat source is passed over the outside of the glass tube. The heat from the heat source sinters the soot to provide a homogenous glass layer. Heating the tube softens the tube and the pressure must be controlled inside the tube to achieve a desired tube diameter. Without a constant target pressure, the tube diameter may detrimentally increase, decrease, or otherwise deform, thereby affecting the quality of the preform and the resulting fibers drawn from the preform.
[0005] Methods for controlling the pressure inside the tube are currently unsatisfactory. For example, known methods of controlling the pressure inside the tube include using a valve to control the flow of the soot and carrier gas, and introducing a counterflow of a gas, such as oxygen, nitrogen, or other inert gas, at a downstream position relative to the flow of soot. In either example, a back-pressure is thereby created in the tube. However, such prior art methods suffer from several drawbacks including, for example, “blowback” caused by the valve sticking in a “closed” position, or imbalances that develop between the tube inlet and exit pressures. Specifically, the valve may become clogged with soot and is prevented from opening properly, some other obstruction within the apparatus may develop, or the counterflow gas may “spike” due to an unintended control loop command. Regardless of the cause, the pressure imbalance must eventually correct itself, often to the detriment of the preform. Short-term imbalances such as those described above can result in large soot agglomerations being propelled backwards into the substrate tube. These instances of blow-back cause imperfections, such as bubbles, that reduce the quality of the preform. Long-term pressure imbalances can cause catastrophic failures if the over-pressurization persists for a sufficient amount of time to cause the preform to burst.
[0006] In view of the preceding discussion, a need exists for an apparatus and method for controlling the pressure in the glass substrate tube without causing imperfections or preform bursting during a CVD process.
ASPECTS OF THE INVENTION
[0007] In a first aspect of the present invention an optical fiber preform fabricating device is provided. The preform fabricating device includes a particle remover for removing soot from a carrier gas, the soot being particles that are not deposited on a substrate tube. A soot collector communicates with the particle remover and contains the soot removed by the particle remover. Further, a control valve communicates with the particle remover. The control valve adjusts a pressure within the substrate tube.
[0008] In a second aspect of the present invention an optical fiber preform fabricating device is provided. The preform fabricating device includes a particle remover, a collector and a valve. The particle remover removes soot from a carrier gas, the soot being particles that are not deposited on a substrate tube. The collector communicates with the particle remover and contains the soot removed by the particle remover. The valve adjusts a pressure within the substrate tube.
[0009] In another aspect of the present invention, a method for fabricating a preform is provided. The method includes the step of removing soot from a carrier gas before the carrier gas passes through a valve, the soot being particles that are not deposited on a substrate tube. The method also includes the step of controlling a pressure and a flow rate of the carrier gas within the substrate tube.
[0010] These and other aspects, features and advantages of the present invention will become apparent from the following detailed description of the preferred embodiments taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] [0011]FIG. 1 is a plan view of a preferred embodiment of the present invention.
[0012] [0012]FIG. 2 is a plan view of features of the preferred embodiment of the present invention.
[0013] [0013]FIG. 3 is a cross-sectional view of a glass tube during a CVD operation.
DETAILED DESCRIPTION OF THE INVENTION
[0014] As explained below in detail, preferred embodiments of the present invention provide an apparatus and method for removing soot particles from a carrier gas and for controlling the diameter of a glass substrate tube during a CVD process. Of course the invention should not be limited solely to such features. These and other features of the preferred embodiments of the present invention are discussed below in detail.
[0015] A deposition apparatus 10 for performing a CVD operation in accordance with the present invention is illustrated in FIG. 1. The deposition apparatus 10 includes a glass working lathe 12 having a headstock 14 and a tailstock 16 . The headstock 14 and tailstock 16 support a substrate tube 18 in such a manner that the substrate tube 18 may be rotated about its longitudinal axis. The substrate tube 18 is mounted in the headstock 14 and tailstock 16 such that a stream of reactants, collectively referred to as soot, entrained in a carrier gas passes longitudinally through the substrate tube 18 . Specifically, the reactants and the carrier gas are fed through the headstock 14 , they react and form soot particles in the substrate tube 18 , and the effluent, which includes carrier gasses and undeposited soot, flows through the tail stock 16 . The soot includes dopants, such as germanium, for affecting optical properties of the finished preform. In a preferred embodiment the soot may also include phosphorous, fluorine, or any other desired materials.
[0016] The glass working lathe 12 also includes a heat source 20 such as a hydrogen and oxygen burner that directs heat against the substrate tube 18 in a defined heated area. The heated area creates a reaction zone within the substrate tube 18 . The heat source 20 is moved co-axially along the rotating substrate tube 18 during the CVD process, thereby causing the reaction zone to move along the substrate tube 18 . Soot is deposited onto the inner surface of the substrate tube 18 within and downstream of the reaction zone and is fused into a homogenous layer by the heat from the heat source 20 . Moving the heat source 20 along the substrate tube 18 is repeated one or more times to deposit additional layers of soot onto the inner wall of the substrate tube 18 . The wall of the substrate tube 18 is thereby increased to a desired thickness. See FIG. 3.
[0017] Not all of the soot is deposited onto the wall of the substrate tube 18 when the soot and carrier gas mixture passes through the reaction zone. The remaining soot and carrier gas mixture exits the substrate tube 18 through the tailstock 16 . As shown in FIGS. 1 and 2, the soot and gas mixture passes through the tailstock 16 and enters a particle removing device 22 for removing the soot particles from the gas stream. Soot particles are thereby prevented from passing back into the substrate tube 18 if there is any inadvertent counterflow of the carrier gas. The particle removing device 22 may be any suitable mechanism for removing the soot particles. Examples of such a device include separators such as a cyclone, impaction box, impingement separator, filter, scrubber, thermal separator or a settling chamber. In a preferred embodiment, a soot collector 24 communicates with the particle removing device 22 and collects the soot particles for later disposal or recycling. The soot collector 24 may be configured as a removable drawer, a bag or box, or any other easily replaceable or easily cleanable structure. Of course the invention is not limited to the above-described structures, and other devices for separating and holding the soot particles are also considered to be within the scope of the present invention.
[0018] In the preferred embodiment, the gas stream exits the particle removing device 22 then passes across a pressure transducer 26 . The pressure transducer 26 may be any known pressure transducer. The pressure transducer 26 detects the pressure of the carrier gas as it exits the particle removing device 22 and, from this detected pressure, the pressure inside the substrate tube 18 may be closely approximated. The position shown in FIGS. 1 and 2 for pressure transducer 26 is only one example. Other ports for pressure measurement can be placed at various points within the system. Also, for increased accuracy, multiple pressure transducers 26 may be used to detect the pressure at multiple points within the deposition apparatus 10 . For example, a pressure transducer 26 may be incorporated into one or more of the particle removing device 22 , the tailstock 16 and the headstock 14 . The pressure within the substrate tube 18 may thus be accurately approximated in accordance with measurements from one or more of the pressure transducers 26 .
[0019] As shown in FIG. 2, the carrier gas passes through a control valve 28 after passing across the pressure transducer 26 . The control valve 28 controls the flow rate of the gas stream as the gas stream passes through the deposition apparatus 10 and thereby controls the gas pressure inside the substrate tube 18 . Specifically, the control valve 28 is adjusted by a controller 30 to regulate the flow rate of the gas in accordance with the pressure detected by the pressure transducer 26 . By way of example, the controller 30 may include a central processing unit and memory with executable code for manipulating data received from the pressure transducer 26 and for outputting a corresponding control signal to the control valve 28 . The control valve 28 may be any conventional pressure proportioning or flow control valve assembly, or any other variable aperture device useable for regulating the flow of gas and/or pressure in response to a control signal or other input. The controller 30 controls the control valve 28 such that the pressure of the carrier gas inside substrate tube 18 reaches and maintains a desired value. The pressure of the carrier gas in the substrate tube 18 is decreased by controlling the control valve 28 to adjust to a more open position. The flow rate of the carrier gas through the control valve 28 and out of the substrate tube 18 is thereby increased, and the pressure within the substrate tube 18 is decreased. Alternatively, the pressure of the carrier gas in the substrate tube 18 is increased by controlling the control valve 28 to adjust to a more closed position. The flow rate of the carrier gas through the control valve 28 and out of the substrate tube 18 is thereby decreased, and the pressure within the substrate tube 18 increases. In accordance with a preferred embodiment of the present invention, the control valve 28 does not suffer performance degradation caused by soot accretion. Instead, the particle removing device 22 removes the soot from the carrier gas before the carrier gas enters the control valve 28 , and the control valve 28 is thus protected from becoming clogged or fouled. Blow-back of gas into the substrate tube 18 resulting from the control valve 28 sticking in the closed position, leading to an imbalance in gas pressures, is thereby prevented. If more than one pressure transducer 26 is used to monitor pressures within the deposition apparatus 10 , the controller 30 adjusts the control valve 28 in accordance with the pressures detected by each of the pressure transducers 26 , or by pre-determined combinations of the pressure transducers 26 .
[0020] The gas stream exits the control valve 28 and passes to downstream components such as a scrubber 32 for further removing components from the carrier gas. For example, the scrubber 32 removes any remaining particles, chlorine gases, germanium, silica, byproducts of reactions in the reaction zone, or any other predetermined components of the carrier gas.
[0021] As described above in detail, a preferred embodiment of the present invention prevents fouling of the control valve 28 , and prevents blow-back of the carrier gas and soot into the substrate tube 18 . In addition to preventing fouling and blow-back, a preferred embodiment of the present invention also controls the diameter of the substrate tube 18 . Specifically, the wall of the substrate tube 18 in the reaction zone is softened when the wall is heated by the heat source 20 . The pressure of the carrier gas is detected by one or more of the pressure transducers 26 and the pressure within the reaction zone of the substrate tube 18 is approximated. The controller 30 then controls the control valve 28 to increase or decrease the flow rate of the carrier gas through the substrate tube 18 in accordance with the pressure detected by the pressure transducer. The difference in pressure between the carrier gas in the substrate tube 18 and ambient pressure outside the substrate tube 18 causes the softened walls of the substrate tube 18 to expand or collapse to reach a desired diameter. Further, unwanted and potentially dangerous expansion of the substrate tube 18 resulting from obstructions caused by soot build-up in the exhaust apparatus is prevented in the manner previously discussed. Specifically, the control valve 28 is prevented from becoming fouled, and an unwanted pressure differential does not occur, because the particle removing device 22 removes unwanted soot particles from the carrier gas stream before the carrier gas stream passes through the control valve 28 . In the foregoing manner the diameter of the substrate tube 18 in the reaction zone is reliably controlled. As the heat source 20 moves along the substrate tube 18 the reaction zone also moves along the substrate tube 18 . The diameter of the entire substrate tube 18 is then controlled in the foregoing manner.
[0022] Although specific embodiments of the present invention have been described above in detail, it will be understood that this description is merely for illustration purposes. Various modifications of and equivalent structures corresponding to the disclosed aspects of the preferred embodiments in addition to those described above may be made by those skilled in the art without departing from the spirit of the present invention which is defined in the following claims, the scope of which is to be accorded the broadest interpretation so as to encompass such modifications and equivalent structures. | An optical fiber preform fabricating device is disclosed. The device includes a particle remover for removing soot from a carrier gas, the soot being particles that are not deposited on a substrate tube. The device also includes a soot collector communicating with the particle remover for containing the soot removed by the particle remover. A control valve communicates with the particle remover, and adjusts a pressure within the substrate tube. | 15,873 |
CROSS-REFERENCE TO RELATED APPLICATION
This application is a United States national phase application of co-pending international patent application number PCT/SI2011/000030, filed Jun. 2, 2011, which claims the benefit of Slovenia Application No. P-201000257 filed Aug. 26, 2010, of which is hereby incorporated by reference in its entirety.
BACKGROUND
The invention refers so a varistor fuse element, which comprises at least a varistor and a melting member and can be integrated into each appropriate DC or AC electric circuit.
According to the International Patent Classification, such inventions belong to electricity, namely to basic electric elements, in particular to overvoltage protection components on the basis of varistors. Furthermore, such invention may also belong to emergency protective circuit arrangements, which are adapted to interrupt the circuit automatically, as soon as undesired deviations with respect to usual operating conditions occur and/or when transient voltage occurs.
The invention is rest on the problem how to arrange a varistor fuse element comprising a combination of a varistor and a melting member that in a simple manner and when possible without introducing additional parts, components and wirings an efficient overvoltage protection will be maintained despite to possible variations of resistance if/whenever these would occur.
Consequently, the purpose of the invention is to create such a fuse, which should in a single and uniform casing comprise a varistor part, which should be capable to protect electric installations against overvoltage impulses and current strokes, as well as an electric fuse, which should be capable to transmit the current stroke due to increased voltage and to interrupt the circuit in the case of permanently increased current, which might occur due to damages in the varistor part. At the same time, such fuse element be available in the form of commonly used protective appliances, in particular electric melting fuses, and should not exceed dimensions thereof.
A varistor fuse element is one of protective appliances, which are intended for integration into electric circuits, in particular such circuits in which the probability of generating transient or transitional voltage due to direct or indirect lightning strike into particular building or its surrounding is pretty high. Such varistor fuse element may be used both in AC or DC installations, and also in electric installations used in exploitation of renewable energy resources, for example in photovoltaic power plants.
Protection against overvoltage, namely protection against short-term overvoltage impulses, is generally known to those skilled in the art and is a standard part in a sequence of protective measures in low-voltage electric installations. Namely, a voltage-depending resistance, the so-called varistor is usually used for such purposes. Varistors are usually manufactured in the form of plates consisting of a special sintered material, e.g. of zinc oxide (ZnO). Thanks to their properties, in normal circumstances the resistance thereof is very high. When exposed to an overvoltage impulse, e.g. due to a lightning strike, the resistance of such varistor is essentially decreasing, and the undesired overvoltage stroke is transmitted to the earth. Upon that, the resistance is increasing again towards the range of electric insulators.
As known, upon several successive current strokes through the varistor problems may occur in regard of changing the resistance of the varistor. By such changing, certain lower currents may be generated within the resistor even by nominal voltage. Such currents lead to overheating of the resistor, which results in further damages within the resistor, until it becomes completely out of order. Of that reason the varistor is normally serial connected with a thermal switch, which is able to operate in such a manner that by to high temperature on the body of the varistor the last is separated out from the circuit. Such thermal switch is usually manufactured in the form of resilient strip, which is soldered onto the varistor body. As soon as the body is then overheated due to current conducted by the nominal voltage, the solder is molten and the circuit is then interrupted by means of such switch. The main deficiency of such switch is the arc, which may occur in such switch and cannot be managed by the switch, which may be quite dangerous in photovoltaic (PV) installations. In such cases the explosion may occur in the switch, by which a part of installation may be damaged or at risk. The situation with said PV installations is in particular problematic because the parallel arc cannot be extinguished until the panel is exposed to the light. Said problem is not just a hypothetic one, and the users have complained that at present available overvoltage protection in PV installations is definitively bound with such problems.
Several approaches in the course of resolving such problems are known in the prior art. The fist possibility is given by the so-called SRF fuse (Surge Rated Fuse), which is serial connected to the varistor and is merely dealing with the question of essentially decreased resistance, through which a short circuit may occur at the nominal voltage. However, the melting threshold of such SRF fuse must be pre-determined at sufficiently high level since otherwise the fuse would be molten whenever the current stroke would occur. Consequently, the fuse is declared with regard to each value kA of impulse, which may still be conducted through such SRF fuse. The main deficiency of such approach results in two separate parts within two separate casings, namely a varistor within its casing and serial SRF fuse in its casing or stand, which have to be integrated installation. Such approach then requires much more space and wirings, which is undesired.
A further approach is described in WO2008/69870 (Ferraz Shawmut). In this case, the varistor is serial interconnected with a thermal switch, which is parallel interconnected with a fuse. A resilient strip of the thermal switch is soldered onto the varistor. When by too high temperature of the varistor the switch is activated, the current is redirected towards the fuse, in which the melting member is then molten, and the arc is herewith extinguished. Such appliance consists of three parts, which is a main deficiency, and moreover, two processes are successively performed, wherein in the first step the solder is molten on the contact of the switch, by which the switch is activated, and upon that in the second step the melting member within the fuse must be molten.
A still further approach is described in WO2004/072992 where the tubular varistor is foreseen, which simultaneously serves as a casing for a fuse having a melting member. However, when the overvoltage occurs, the casing of such fuse cannot serve as a resistance anymore, since the varistor becomes conductive at least for a short time period, so that the melting member of such fuse is then unable to perform correctly the main function thereof. Of that reason, at least according to the knowledge of the present inventor, this solution has never been practically applied.
It is moreover known to those skilled in the art that a so-called M-effect is performed for the purposes of interrupting each melting member whenever to high current has occurred, which might lead to overloading of installations. Such effect is based on the fact that the melting temperature of a copper-tin alloy is lower than the melting temperature of each of these metals as such. From quite construction point of view, melting members in fuses are manufactured in such a manner that the tin in the form of solder is placed on a copper melting member adjacent to a weak portion which is also foreseen on such melting member. When exposed to sufficiently high current, the temperature of the weak portion is increased, which leads to melting of tin within the solder, wherein said copper-tin alloy has not only a lower melting temperature but also higher electric resistance. Consequently, the resistance of the melting member in the area of said weak portion is increased, which leads to still further heating of the solder and still more intensive producing the copper-tin alloy. The whole process is developed quickly up to interruption of the melting member in the area of said weak portion. Operation of melting fuses and melting members is described in literature relating to operation and exploitation of such fuses.
SUMMARY
The invention refers to a varistor fuse element, comprising a cylindrical varistor, the resistance of which depends on voltage, as well as a cylindrical fuse, which are serial electric connected to each other. Said varistor consists of a pair of electric conductive electrodes, which are separated from each other by means of a body consisting of a material having a resistance which is depending on electric voltage, while said fuse consists of an electric insulating body, which is furnished with contact means which consist of an electric conductive material and are located on the end portions thereof and connected to each other by means of a melting member, which consists of electric conductive material and is furnished with a weak portion having a pre-determined cross-section which is adjusted for the purpose of melting and interrupting the contact between said contact means when the fuse is electrically overloaded.
In this case the invention provides that the fuse comprising a round tubular body and a varistor also comprising round tubular body are inserted within each other in such a manner that the varistor is placed within a longitudinal passage in the body of the fuse which is filled with the arc extinguishing material, and that electric conductive contact means are available on the end portions of said fuse body, wherein the electrode on the external surface of the varistor is electrically interconnected with one contact means of the fuse, while the other contact means thereof is via the melting member electrically interconnected with the other electrode of the varistor, which is available on the internal surface of the body of said varistor.
Another aspect of the invention refers to a varistor fuse element, comprising a cylindrical varistor, having the resistance which depends on voltage, as well as a cylindrical fuse, which are electric interconnected in a serial manner, wherein said varistor consists of a pair of electric conductive electrodes, which are separated from each other by a body consisting of a material having a resistance which is depending on electric voltage, and wherein said fuse consists of an electric insulating body, which is furnished with electric conductive contact means which are located on the end portions thereof and are connected to each other by means of a melting member, which consists of electric conductive material and comprises a weak portion having a pre-determined cross-section which is adjusted for the purposes of melting and interrupting the contact between said contact means when the fuse is electrically overloaded.
In this case the invention provides that the fuse comprising a round tubular body and the varistor also comprising a round tubular body are inserted within each other, so that the fuse is inserted within a longitudinal passage in the round tubular body of said varistor comprising the first electrode placed on the external surface and at least partially on one of the front surface thereof, while the second electrode of the varistor is located on the internal surface of said varistor body, wherein said fuse is exposed to the heat generated within the varistor due to varying the resistance thereof and comprises a longitudinal passage which is filled with an arc extinguishing material as well as melting member which extends throughout said passage and by means of which two contact means arranged on the end portions of the fuse are connected to each other indirectly via appropriate solder, and wherein the first contact means of the fuse is arranged within said passage in the body of the varistor and is electrically interconnected with the electrode on the internal surface of the body of the varistor, while the second contact means is arranged outside of the passage of the body of the varistor and is included in the electric circuit together with the other electrode located on the external surface and/or the front surface of the body of the varistor.
Said melting member comprises at least one weak portion having a pre-determined transversal cross-section.
In accordance with the first aspect of the invention, the melting member is via the solder electrically connected to the second electrode of the varistor, which is located on the internal surface of the body of the varistor. The weak portion on the melting member is preferably located adjacent to the solder. Moreover, said second electrode of the varistor and the melting member are both interconnected i.e. coated with the colder until the last is molten. The melting member is preferably pre-tensioned prior to coating thereof by solder and has a tendency of deflecting apart from the electrode of the varistor.
In general, the invention also provides that the melting temperature of the solder is lower than the melting temperatures of materials of the melting member and of the electrode of the varistor cooperating therewith. The material of the solder is preferably defined in such a manner that the resistance thereof is increasing by increasing the temperature. Moreover, the arc extinguishing material, which is present within the passage of the fuse and preferably also within the passage of the varistor, is preferably silica.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in more detail on the basis of two embodiments, which are shown in the attached drawing, wherein
FIG. 1 is a longitudinal cross-section through the first embodiment; and
FIG. 2 is a longitudinal cross-section through the second embodiment.
DETAILED DESCRIPTION
The object of the invention is a construction concept of product, by which the previously exposed problem has been resolved. The proposed solution is based on a cylindrical fuse 2 and a varistor 1 in the form of a cylindrical tube. Two embodiments of will be described. In both embodiments, said fuse 2 and said varistor are arranged coaxially within each other, wherein in the first embodiment according to FIG. 1 the varistor 1 is placed within the passage of a round tubular body 20 of the fuse 2 , while in the second embodiment on the contrary the fuse 2 is inserted within a passage in a round tubular body 10 of the varistor. In this, the term “round tubular” body 10 of the varistor 1 or “round tubular” body 20 of the fuse 2 means a body in the form of a round tube, namely of a tube having a round transversal cross-section.
Said round tubular body 10 of the varistor consists of a material (e.g. of ZnO) by which the conductivity is depending on contact voltage, so that such material may be used as insulator up to a pre-determined value of voltage. As soon as the voltage has overcome such pre-determined value, depending on thickness and configuration, the conductivity is essentially increased, by which the current stroke due to the increased voltage is discharged via the earth connection. In addition to that, due to such cylindrical shape of said body 10 in comparison with commonly used plate-like varistor 1 the complete fuse element as a commercial product is then available in a much more compact form.
As known to those skilled in the art, said tubular body 2 of the fuse 2 consists of an insulating material, preferably of ceramics or a plastic composite. Two contact means 21 , 22 are placed on the end portions 23 , 24 of the body 20 and are electrically interconnected via a melting member 25 .
The first embodiment according to FIG. 1 is based on a cylindrical fuse 2 having a sufficiently wide internal diameter of the tubular body 20 . (i.e. at least Type CH 22 or larger). In such case, the varistor 1 is manufactured as a cylinder, which is then inserted into a passage of the tubular body 20 of the fuse 2 . A cylindrical varistor 1 is manufactured in such a manner that both electrodes 11 , 12 , which are separated from each other by means of said body 10 of the varistor 1 , are available in the form of silver layers on the external surface 14 and the internal surface 13 of said body 10 , wherein the outer electrode 11 is electrically interconnected with the adjacent first contact means 21 of the fuse 2 , which is in this particular case performed in the area of one of both front surfaces 15 , 16 of the body 10 , while the melting member 25 of the fuse 2 is in this particular case attached to the internal electrode 12 of the varistor 1 by means of a solder 250 and is moreover electrically interconnected with the second contact means 22 of the fuse 2 . Said melting member 25 of the fuse 2 preferably consists of copper and extends throughout the passage in the tubular body 20 of the fuse 2 , which should be normally filled with an arc extinguishing material 26 , in particular with sand on the basis of silica, which is capable to eliminate arc, which might occur when the melting member 25 is interrupted. Said solder 250 preferably consists of an alloy on the basis of copper and tin.
The melting member 25 is conceived in such a manner that the first weak portion 25 ′ is located quite in the initial area adjacent to the solder 250 i.e. adjacent to the location of soldering to the electrode 12 of the varistor. Such, the solder 250 is simultaneously used on the one hand for the purposes of establishing of an electric conductive interconnection between the melting member 25 and the electrode 12 of the varistor, and on the other hand also for performing a so-called M-effect, which is required for the purposes of interrupting the melting member 25 in the case of overloading, or by low currents, respectively. The area, in which the solder 250 is applied, is arranged in such a manner that the melting member 25 as such is not in contact with the internal electrode 12 of the varistor 1 which is located on the internal surface 13 of the body 10 , and prior to applying the solder 250 , the melting member 25 is located at certain gap apart from said electrode 12 of the varistor, which gap is then filled with the solder 250 . As soon as the solder 250 is molten, the liquid solder flows out from said gap between the melting member 25 and the electrode 12 of the varistor 1 towards the arc extinguishing material 26 , namely into pores between silica particles. In fact, two processes of interrupting the contact between the melting member 25 and the electrode 12 are actually available and applied simultaneously or separately, depending on each particular conditions related to electric current and temperature. The rest of the melting member 25 outside of said weak portion 25 ′ is conceived in such a manner that the electric circuit throughout the fuse 2 is interrupted as soon as a short-circuit occurs, or when the current is essentially increased. Besides, the melting integral thereof must be sufficiently high, so that quite similarly like in a so-called SRF-fuse, the current stroke of nominal range in kA should not initiate melting of the melting member 25 and interrupt protective effect during the period of such impulse.
In this particular case, the complete interior of the fuse 2 and also of the varistor 2 is filled with silica, which is used as the material 26 for extinguishing the arc, which might be generated by when the melting member 25 is interrupted.
In accordance with a further aspect of the invention, the melting member 25 is mounted within the fuse 2 in a pre-tensioned state, by which upon melting it is then automatically deflected away from the corresponding electrode 12 of the varistor, so that efficiency and reliability of such varistor fuse element according to invention may be still additionally improved.
Whenever an overvoltage impulse occurs, conductivity of the varistor 1 is essentially increasing, so that the current is able to pass the body 10 between the electrodes 11 , 12 radially and then via the melting member 25 , which is however not melting in such situation. Such stroke i.e. overvoltage is then lead to the earth connection.
Whenever the varistor 1 is disabled or at least partially damaged, conductivity of the varistor is always increasing, although the overvoltage does not occur at all. Depending on the current intensity, the following possibilities may occur:
Whenever a low current of several mA up to approximately 1A is passing through the varistor 1 , the body 10 of the varistor starts overheating, and the solder 250 between the varistor 1 and the melting member 25 starts melting, by which the contact between the electrode 12 of the varistor 1 and the melting member 25 of the fuse 2 is interrupted; whenever the medium current within the range between approx. 1 A and approx. 10A is passing through the varistor 1 , said M-effect occurs in the first weak portion 25 ′ of the melting member 25 , by which the heat is generated both in said weak portion 25 ′ and in the varistor 25 , and interruption is then performed much earlier than in situation without overheating of the varistor 1 ; whenever the current within the range between several hundred A and several kA is passing the varistor 1 , the varistor 1 as such cannot represent a high resistance, while the melting member 25 is held in a short-circuit and is molten across the complete cross-section within a quite short interruption period of several ms.
In all three above situations, interruption of the path of the current occurs within the passage in the body 20 of the fuse 2 and therefore in the area where the arc extinguishing material 26 i.e. the silica is present, so that the arc is rapidly extinguished. The fact that the arc can never occur outside of the fuse 2 is apparently an essential benefit in comparison with known solutions, and may simultaneously with a compact construction and combining the fuse 2 with a thermal switch lead to achieving much higher interrupting efficiency of the fuse 2 .
Another embodiment according to FIG. 2 is based on a cylindrical varistor 1 , wherein the fuse 2 , e.g. a cylindrical SRF fuse, is embedded within the passage and where the thickness of the wall of the body 10 is determined with regard to each expected level of the voltage. Functioning of the varistor 1 is performed radially through the active body 10 between both electrodes 11 , 12 , and the fuse 2 is serial interconnected with the varistor 1 . Also in this case the varistor 1 and the fuse 2 are arranged coaxially within each other, wherein the fuse 2 is placed within the passage extending throughout the varistor 1 . However, in this case the serial interconnection of the varistor 1 and the fuse 2 is much more conventional. Namely, the melting member 25 is not soldered directly to the electrode 12 like in the first embodiment, and the complete fuse 2 is inserted within the cylindrical varistor 1 . Said M-effect occurs on the melting member 25 in a classic manner like in any other fuse 2 . Whenever the varistor 1 is damaged, the heat generated by such damaged varistor 1 is then via both contact means 21 , 22 and the body 20 of the fuse 2 transferred to the melting member 25 .
In this case, the fuse 2 and the varistor 1 , which are inserted within each other, are embedded between contact plates 31 , 32 , which are furnished with contact protrusions 310 , 320 , which are adapted for inserting into not-shown seats for receiving the fuse 2 . The external electrode 11 of the varistor 1 is maintained in the electricity conducting contact with the contact plate 32 on the front surface 16 , while the contact 21 means 21 of the fuse 2 is maintained in the electricity conducting contact with the other contact plate 31 . Electric current between the contact plates 31 , 32 is therefore able to pass through the fuse 2 and through the varistor 1 which is serial interconnected therewith, namely through the contact plate 32 and then through the external electrode 11 as well as the body 10 towards the internal electrode 11 of the varistor 1 , and then via the contact means 22 and the melting member 25 , which is by means of the solder 250 connected thereto, towards the other contact means 21 of the fuse and then through the other contact plate 31 . | The purpose of the invention is to create such a varistor fuse element, which should within a single housing include both a varistor ( 1 ) as well as an electric fuse ( 2 ), wherein said varistor part i.e. a varistor ( 1 ) is intended to protect each electric installation against overvoltage impulses and consequently against current strokes, while the fuse ( 2 ) is capable to transmit the current stroke due to increased voltage and to interrupt each permanently increased electric current, which might occur due to defects on the varistor ( 1 ). Moreover, such varistor fuse should not exceed dimensions of already known and widely used protective means, in particular melting fuses. In accordance with the invention, the fuse ( 2 ) with its round tubular casing ( 20 ) and the varistor, which is also embedded within a round tubular casing ( 10 ), are serial interconnected and arranged coaxially within each other. | 25,191 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a semiconductor device in which electrical connection between a pad of semiconductor chip and an electrode of a circuit substrate is performed via a coil spring. The present invention also relates to a method of manufacturing such semiconductor device.
[0003] 2. Description of the Prior Art
[0004] In order to comply with increase in processing speed of a semiconductor chip, it has been known and put into practice use that a semiconductor chip is mounted or connected to a circuit substrate in a flip chip bonding manner to shorten interconnection length there between.
[0005] In the flip chip bonding manner, a pad formed on the semiconductor chip and an electrode of the circuit substrate are directly bonded together via, for example, a solder ball. This method can provide the shortened interconnections, thereby preventing the occurrence of floating capacitance and inductance and permitting high-speed processing.
[0006] However, due to the direct bonding of the pads of the semiconductor component and the electrodes of the circuit substrate, stresses caused by the difference in thermal expansion between the semiconductor chip and the circuit substrate are concentrated in the bonding area of the chip and board to damage those areas. It has been proposed in the Japanese Patent Laid-Open No. 2002-151550 such a device that is shown in FIG. 1. In this device, each pad 102 of a semiconductor chip 101 and each electrode 105 of a circuit substrate 104 are bonded via an electrically conductive coil spring 107 by the both ends of the spring 107 are solder-connected respectively to a solder bump 103 of the chip 101 and a solder electrode 106 of the substrate 104 . With this construction, the coil spring 107 can absorb the differences in thermal expansion between the chip 101 and the circuit substrate 104 .
[0007] The present inventor, however, recognized that each of the solders 103 and 106 is sucked into the interior of the coil spring due to the capillary phenomenon, resulting to decrease in bonding strength between the coil spring 107 and the chip 101 and/or between the coil spring 107 and the substrate 104 . The inventor has made it clear that this decrease in strength is due to the fact that the substantive amount of solder 103 and/or 106 has flown into the coil spring 107 .
SUMMARY OF THE INVENTION
[0008] According to the present invention, there is provided a semiconductor device in which a pad of a semiconductor chip is solder-bonded to an electrode of a circuit substrate via a coil spring, at least on inner surface of which is covered with a material of low wettability against a solder.
[0009] The capillary phenomenon that a solder is sucked into the interior of the coil spring during solder bonding is prevented by the material of low solder. As a result, in the bonding area between the coil spring and the pad or the bonding area between the coil spring and the electrode, the solder remains in an amount necessary for solder bonding. Strong soldering bonding can be obtained by this action.
BRIEF DESCRIPTION OF THE DRAWINGS
[0010] The above and other objects, advantages and features of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
[0011] [0011]FIG. 1 is a view showing a semiconductor device according to the prior art;
[0012] [0012]FIG. 2 is a sectional view of a bonding area of the prior art;
[0013] [0013]FIG. 3 is a view of a semiconductor device of the first embodiment of the invention;
[0014] [0014]FIG. 4 is an enlarged view of a coil spring 7 of FIG. 3;
[0015] [0015]FIG. 5 is a schematic representation of an example of the second embodiment of the invention;
[0016] [0016]FIG. 6 is a schematic representation of an example of the second embodiment of the invention;
[0017] [0017]FIG. 7 is a schematic representation of an example of the fourth embodiment of the invention;
[0018] [0018]FIG. 8 is a schematic representation of an example of the fourth embodiment of the invention;
[0019] [0019]FIG. 9 is an explanatory drawing of a method of forming a coil spring of FIG. 8;
[0020] [0020]FIG. 10 is an explanatory drawing of a method of forming a coil spring in which a material of high wettability by the solder is formed further on an outer surface in FIG. 8;
[0021] FIGS. 11 ( a ) and ( b ) are each an explanatory drawing of a method of manufacturing a semiconductor device of the first embodiment of the invention; and
[0022] FIGS. 12 ( c ) and ( d ) are each an explanatory drawing of a method of manufacturing a semiconductor device of the first embodiment of the invention (continued from FIGS. 11 ( a ) and ( b ))
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] Before describing of the present invention, the prior art will be further explained in detail with reference to FIG. 2 in order to facilitate the understanding of the present invention. FIG. 2 shows an enlargement view of the FIG. 1 device and corresponds to the solder bonding between the coil spring 107 and the pad 102 of the semiconductor chip 101 . As shown in the figure, the solder, which has been originally formed on the pad 102 as a solder bump, is sucked up along an inner side surface of the coil spring 107 as indicated by the reference numeral 1031 . For this reason, the amount of solder which remains in the solder bonding area decrease. As a result, the strength of solder bonding decrease.
[0024] The invention will be now described hereinbelow with reference to illustrative embodiments. Those skilled in the art will recognize that many alternative embodiments can be accomplished using the teachings of the present invention and that the invention is not limited to the embodiments illustrated for explanatory purposes.
[0025] [0025]FIG. 3 is a side view showing the configuration of a semiconductor device in the first embodiment of the invention and FIG. 4 shows an example of coil spring used in the flip chip bonding of this semiconductor device. This semiconductor device 10 is comprised by a semiconductor chip 1 , a circuit substrate 4 and a coil spring 7 . The semiconductor chip 1 is formed from Si, GaAs, Ge, etc. The circuit substrate is formed from glass epoxy, alumina, ceramics, etc. The coil spring 7 is formed from a material of high electrical conductivity, such as Cu. The coil spring 7 used in this embodiment is fabricated by winding a Cu conductive wire having a thickness of 30 μm and has a length of 500 μm, a diameter of 150 μm and a pitch of 25 μm. The pitch called here refers to. “P” shown in FIG. 4. A plurality of pads 2 are formed on a surface of the semiconductor chip 1 and a plurality of electrodes 5 are formed on a surface of the circuit substrate 4 . In this embodiment, the diameter of the pad 2 and electrode 5 is 150 μm, the same value as the diameter of the coil spring 7 . The pad 2 and electrode 5 are formed from Al (aluminum), Ni (nickel), Cu (copper), etc.
[0026] The semiconductor chip 1 and circuit substrate 4 are arranged in such a manner that the surface on which the pads 2 are formed and the surface on which the electrodes 5 are formed are opposed to each other. A solder 3 formed from a Pb—Sn alloy is formed on the surface of the pad 2 and a solder 6 formed from a similar alloy is formed on the surface of the electrode 5 . By use of these solders the pad 2 and an end of the coil spring 7 are bonded together and the electrode 5 corresponding to this pad and the other end of the coil spring 7 are bonded together. As shown in FIG. 4, a material 27 of low solder wettability is formed on the surface of the coil spring 7 so that the solder is not sucked into the interior of the coil spring 7 . As a result, the solder remains on the pad 2 and electrode 5 in an amount necessary for the bonding with the coil spring 7 and strong solder bonding can be obtained.
[0027] A semiconductor device of this embodiment can be manufactured by the following procedure.
[0028] First, as shown in FIG. 11( a ), a bonding pad 2 is formed on a surface of a semiconductor chip 1 and a solder 3 is formed on this bonding pad 2 . The solder 3 can be formed by the ball mounting method, a printing method using a mask, the plating method, etc.
[0029] Next, as shown in FIG. 11( b ), a coil spring 7 with the material 27 of low solder wettability is supplied and arranged in each spring positioning hole 11 of a jig 12 in an upright manner. It is desirable that the jig 12 be formed from a material having a coefficient of thermal expansion close to that of the semiconductor chip 1 and heat resistance. The spring positioning hole 11 is formed by a processing method using a drill, a laser, etc. When the diameter of the spring positioning hole 11 is about 10 μm larger than the diameter of the coil spring 7 , it becomes easy to set the coil spring 7 . An evacuation hole 13 is provided on the back surface of the jig 12 .
[0030] Next, as shown in FIG. 12( c ), the jig 12 is inverted with the coil spring 7 kept in the positioning hole 11 by evacuating air from the evacuation hole 13 . Subsequently, the jig 12 is moved in such a manner that each coil spring 7 is positioned above the solder 3 formed on the semiconductor chip 1 . Incidentally, a flux is applied beforehand to the solder 3 or coil spring 7 . Subsequently, with the semiconductor chip 1 and the jig 12 kept as one piece, local heating treatment is performed by a reflow furnace or the pulse heat method. At this time, the solder 3 is melted and one end of each coil spring 7 is bonded to the pad 2 by the solder 3 . Although the melted solder is sucked into the interior of the coil spring of the prior art, the material 27 of low solder wettability of this invention prevents the melted solder 3 from being sucked into the coil spring 7 . Subsequently, by performing the cleaning and removal of the flux, a semiconductor chip in which one end of the coil spring 7 is bonded to the pad 2 by the solder 3 is obtained.
[0031] Next, as shown in FIG. 12( d ), a circuit substrate 4 on which electrodes 5 are formed is prepared. The electrode 5 is fabricated from Cu, Ni, Au, etc. The circuit substrate 4 is formed from glass epoxy, alumina, ceramics, etc. A solder 6 is formed on the electrode 5 . Subsequently, the semiconductor chip 1 to which the coil springs 7 are bonded is reversed and the semiconductor chip 1 is mounted on the circuit substrate 4 in such a manner that the coil spring 7 is positioned above the solder 6 formed on the circuit substrate 6 .
[0032] Next, the same local heating treatment as described above is performed and the solder 6 is melted, whereby the end of the coil spring 7 is bonded to the electrode 5 by the solder 6 . In this case, the compositions of the solder 3 and the solder 6 are adjusted so that the melting point of the solder 6 becomes lower than the melting point of the solder 3 . As a result of this, the other end of the coil spring 7 can be bonded to the electrode 5 by the solder 6 without affecting the bonded state already completed between coil spring 7 and solder 3 . Other embodiments of this invention can be manufactured in the same manner mentioned above.
[0033] In the second embodiment, the shape of the coil spring 7 in the first embodiment is changed. Examples of shape of the coil spring 7 are shown in FIGS. 5 and 6. FIG. 5 shows an example of coil spring in which the pitch between ends 8 a and 8 b is smaller than the pitch between middle parts 8 c and 8 d . As shown in this example, the pitch of smaller one can be set to 0. By adopting this shape, the contact area between the end of the coil spring 7 and the solder increases and stronger solder bonding can be obtained. FIG. 6 shows a coil spring in which the middle part is linear. By adopting this shape, the space in the interior of the coil spring decreases and the amount of solder sucked into the interior of the coil spring can be reduced. As a result, the solder remains on the pad and electrode in an amount necessary for solder bonding and strong solder bonding can be obtained.
[0034] In the third embodiment, the material of low solder wettability in the first embodiment is changed. Insulating materials, such as resin and metal oxide, and metals of low wettability, etc. can be used as the material of low wettability 27 in FIG. 4. When resin is used, a resin layer can be formed on the coil spring surface by applying a prescribed resin to the surface of a coil spring formed from a material of good electrical conductivity. When a metal oxide film is used, a metal oxide film can be formed on the coil spring surface by heating a metallic coil spring in an oxygen atmosphere. For example, when the coil spring is formed from Cu, the metal oxide film becomes a copper oxide film. When a metal of low wettability is used, a metal film of low wettability can be formed on the coil spring surface by using electrolysis plating or electroless plating. Cr etc. can be used as a metal material of low wettability.
[0035] In the fourth embodiment, the place where a material of low wettability is formed in the first embodiment is changed. A material of low wettability may be formed on the whole surface of the coil spring or may be partly formed as shown in FIGS. 7 and 8. In FIG. 7, the material of low wettability 27 is formed in parts other than ends 30 a . By adopting this configuration, it is possible to ensure wettability at the ends 30 a where the solder must adhere. As a result, stronger solder bonding can be obtained. Furthermore, by forming a material of high wettability at the 30 a where a material of low wettability is not formed, the ends 30 a and the solder are brought into closer contact with each other and stronger solder bonding can be obtained. In FIG. 8, the material of low wettability 27 is formed on an inner side surface 26 a of the coil spring. If the material of low wettability 27 is formed on the inner side surface 26 a of the coil spring, it is possible to reduce the degree of the capillary phenomenon. As a result, the solder remains on the pad 2 and electrode 5 in an amount necessary for solder bonding and it is possible to adequately obtain the effect that solder bonding becomes strong. Also, by preventing the material of low wettability 27 from being formed on an outer side surface 26 b of the coil spring, the outer side surface 26 b of the coil spring and the solder come into close contact with each other and stronger solder bonding can be obtained.
[0036] In forming a material of low wettability in part of the coil spring, the following method can be adopted. When resin is used as a material of low wettability, a prescribed resin is applied to a necessary place. When a metal oxide film is used as a material of low wettability, a metallic coil spring is first heated in an oxygen atmosphere and a metal oxide film is formed on the whole surface of the metallic coil spring. By causing the part 30 a of FIG. 7 and the part 26 b of FIG. 8 in the metal oxide film to fly by laser irradiation thereby to remove them, it is possible to form a metal oxide film in parts other than the end and outer side surface of the coil spring as shown in FIGS. 7 and 8. When the metal material of low wettability 27 is formed on the inner side surface 26 a of the coil spring as shown in FIG. 8, the following method can be adopted. First, as shown in FIG. 9, a metal of low wettability 271 is formed by the plating method etc. only on one side of a conductive wire 28 . By winding this conductive wire 28 in such a manner that the metal of low wettability 271 is provided on the inner side surface of the coil spring, it is possible to obtain the coil spring in which the metal of low wettability 271 is formed on the inner side surface.
[0037] Stronger solder bonding can be obtained when a material of high solder wettability is formed on the outer side surface in addition to the formation of the metal of low wettability on the inner side surface of the coil spring. This is due to the following principle. Because the material of low wettability is formed on the inner side surface in the interior of the coil spring, the suction of the solder into the interior of the coil spring is suppressed. On the other hand, because the material of high wettability is formed on the outer side surface of the coil spring, the solder spreads up along the outer side surface of the coil spring. At this time, the sucking up of the solder into the interior of the coil spring is more suppressed because a large amount of solder gathers on the outer side surface. At the same time, a larger amount of solder comes into contact with the outer side surface of the coil spring. Owing to the combined effects of the two phenomena, strong solder bonding can be obtained. For example, Au can be used as the material of high wettability.
[0038] A coil spring in which a material of low wettatbility is formed on the inner side surface and a material of high wettatbility is formed on the outer side surface can be made by the following method. First, as shown in FIG. 10, a material of low wettability 27 such as Cr is formed on one half surface of the conductive wire 28 and a material of high wettability 29 such as Au is formed on the other half surface. Next, this conductive wire 28 is wound in such a manner that the material of low wettability 27 is provided on the inner side surface to form a coil spring.
[0039] It is apparent that the present invention is not limited to the above embodiments, but may be modified and changed without departing from the scopes and spirits of the invention. | Disclosed herein is a semiconductor device in which a semiconductor chip is bonded at its pad to an electrode of a circuit substrate via a coil spring by solder-connecting both ends of the spring respectively to the pad and the electrode. There is provided a material having low solder wettability that covers at least part of the surface of the coil spring, so that the solder is prevented from being sucked into the Interior of the coil spring.
A semiconductor device of the present invention comprises a semiconductor chip, a circuit substrate and a coil spring electrically connecting the semiconductor chip and the circuit substrate by a solder. In order to prevent the solder from being sucked into the interior of the coil spring, a material having low wettability by the solder is formed on the surface of the coil spring. | 18,653 |
BACKGROUND OF THE INVENTION
[0001] 1. Field of Invention
[0002] This invention is directed to systems, methods and structures for manipulating the airflow resulting from fluid ejector carriage motion in fluid ejection devices.
[0003] 2. Description of Related Art
[0004] A variety of systems, methods, structures and/or devices are conventionally used to remove mist which is generated during the operation of fluid ejection devices, such as, for example, ink jet printers. In fluid ejection systems, mist removal is recognized as a significant problem. Very small residual droplets of fluid, such as, for example, ink in ink jet printers, are produced during the fluid ejection process. The residual droplets get caught up in the airflow generated by fluid ejector carriage motion. The residual droplets land indiscriminately, over a period of time, on internal surfaces of the fluid ejection devices. The film left by the residual droplets coats various internal surfaces of the fluid ejection device resulting in, not only cleanliness issues, but also impact to the operation of the fluid ejection device. Specifically, when the film that results from dry residual droplets accumulating on structures along which the carriage is designed to translate, such as, for example, fluid ejector carriage guide rods, the film can impede carriage motion. Additionally, accumulation on various internal sensors degrades the performance of these sensors.
[0005] The conventional solution for dealing with mist removal is to add separate, often electrically-driven, fans that can include filters. The disadvantages associated with the addition of separate fans include additional weight and/or structure, greater noise, and increased potential for failure, as well as increased cooling and energy requirements to support the additional fans and like devices.
[0006] A variety of systems, methods, structures and/or devices are conventionally used to dissipate heat in thermal fluid ejector modules of fluid ejection devices. The thermal fluid ejector modules of fluid ejection devices, such as, for example, ink jet printers, generate significant amounts of residual heat as the fluid is ejected by heating the fluid to the point of vaporization. This residual heat changes the performance, and ultimately the ejection quality, if the heat remains within the fluid ejector module. During lengthy operation or heavy coverage ejection, the temperature of the thermal fluid ejector module can exceed an allowable temperature limit. Once the temperature limit is exceeded, a slow down or cool down period is normally required to maintain ejection quality.
[0007] Many fluid ejection devices, such as, for example, printers, copiers and the like, improve throughput by improving thermal performance. Various techniques are used to remove heat from the fluid ejector module. These techniques include: diverting excess heat into the fluid being ejected; using heat sinks to conduct heat away from the fluid ejector module; and, as with residual mist removal, adding separate fans to increase the total volume of air circulating throughout the fluid ejection device facilitating additional cooling.
[0008] Improving heat transfer away from fluid ejection elements can be accomplished by directing flow of ambient air through the fluid ejector carriage and across the heater elements of the fluid ejection module housed in the carriage, and additionally across heat sinks, when installed. U.S. Pat. No. 6,382,760 to Peter, incorporated herein by reference in its entirety, discloses various exemplary embodiments of structures and/or devices for the manipulation of airflow through a fluid ejector carriage for cooling the heater elements and heat sinks.
[0009] A variety of systems, methods, structures and/or devices are conventionally used to dry the fluid deposited on a receiving medium by fluid ejection devices and/or to set certain “hot melt” fluids deposited on a receiving medium in a semi-molten state. Print quality in fluid ejection printer devices is enhanced when the fluid ejected onto the receiving medium is rapidly dried and/or set. Again here, separate fans usable to force airflow across the receiving medium have conventionally facilitated this function.
[0010] In all cases, the addition of separate fans for mist removal, fluid ejection element cooling, and receiving medium drying results in the disadvantages of additional weight, size, noise, heat production, and/or energy required in the fluid ejection device.
SUMMARY OF THE INVENTION
[0011] This invention provides systems, methods and structures for manipulating the airflow resulting from fluid ejector carriage motion.
[0012] This invention separately provides systems, methods and structures for containing the sweep path of a fluid ejector carriage as the fluid ejector carriage is driven in a substantially reciprocating fashion along structures upon which the fluid ejector carriage translates, such as, for example, carriage guide rods and/or rails.
[0013] This invention is separately directed to systems, methods and structures for improving mist removal, fluid ejector element cooling and fluid drying/setting in fluid ejection devices.
[0014] In various exemplary embodiments of the systems, methods and structures according to this invention, the fluid ejector carriage sweep path is enclosed by forming the interior cavity of the fluid ejection device to closely surround a fluid ejector carriage containing at least one fluid ejection module and structures upon which the fluid ejector carriage translates, such as, for example, carriage guide rods and/or rails. For ease of understanding and depiction, guide rods and/or rails will be shown and referred to as exemplary structures upon which a fluid ejector carriage translates. It should be appreciated, however, that the use of the terms guide rods and/or rails throughout is intended to be exemplary only and in no way limiting to the embodiment of any structure upon which a fluid ejector carriage translates.
[0015] In various exemplary embodiments of the systems, methods and structures according to this invention, the interior cross-sectional area of a resulting sweep path containment is sized such that it closely fits the silhouette of the sides of the fluid ejector carriage as manufactured or as modified with the addition of separate conforming structures.
[0016] In various exemplary embodiments of the systems, methods and structures according to this invention, the sweep path containment is generally closed on all sides, except for the face bounded by the receiving medium, and vented to a specific receiving area adjoining the containment or vented outside the fluid ejection device within which it is contained. The resulting effect is the ability to manipulate the airflow generated by fluid ejector carriage motion in order to accomplish one or more beneficial purposes.
[0017] In various exemplary embodiments of the systems, methods and structures according to this invention, containment of the fluid ejector carriage sweep path is accomplished by specifically molding or manufacturing the internal surfaces of existing fluid ejection device components, such as, for example, casings and/or covers, to substantially enclose the fluid ejector carriage sweep path to contain airflow therein. In various exemplary embodiments of the systems, methods, and structures according to this invention, separate structures, such as, for example, shrouds, and/or individual panels may be inserted in the vicinity of the fluid ejection carriage to form a sweep path containment.
[0018] In various exemplary embodiments of the systems, methods and structures according to this invention, the cross-sectional area of the sweep path containment should conform as nearly as possible with the cross-sectional profile, or silhouette, of the fluid ejector carriage as manufactured or as augmented.
[0019] In various exemplary embodiments of the systems, methods and structures according to this invention, the silhouette of the sides of the fluid ejector carriage can be manipulated, shaped and/or enlarged to fit the internal cross-sectional profile of the fluid ejector sweep path containment by molding or manufacture, or, for example, with the addition of appropriately sized and shaped lightweight baffles to the sides of the fluid ejector carriage.
[0020] In various exemplary embodiments of the systems, methods and structures according to this invention, openings, such as, for example, vents and/or channels, are provided at either end of the fluid ejector carriage sweep path containment to channel air from the fluid ejector carriage sweep path containment to outside the fluid ejection device. The fluid ejector carriage, conforming in silhouette to the internal cross-sectional area of the fluid ejector carriage sweep path containment, acts as a piston to draw air in through the opening at one end of the containment while expelling air through the opening at the other end of the containment to facilitate mist removal.
[0021] In various exemplary embodiments of the systems, methods and structures according to this invention, simple channels usable to direct the exhausted air out through the top, bottom, back, or front of the fluid ejection device are added. In various exemplary embodiments of the systems, methods and structures according to this invention, filters are added in proximity to the openings.
[0022] In various exemplary embodiments of the systems, methods and structures according to this invention, openings, such as, for example, vents and/or channels, are added to the fluid ejector carriage to allow air to flow through the fluid ejector carriage to be drawn past heater elements, and/or installed heat sinks, if any, contained in the fluid ejector carriage to facilitate cooling.
[0023] In various exemplary embodiments of the systems, methods and structures according to this invention, at least one additional opening in the face of the fluid ejector carriage that houses or mounts the fluid ejection module may be introduced. Airflow exhausted through such opening facilitates drying and/or setting the fluid deposited on the receiving medium.
[0024] It should be appreciated that the functions of mist removal, fluid ejector cooling and fluid drying/setting can be accomplished as individual tasks, or in any combination, based on the manipulation of the airflow accomplished in the various embodiments of systems, methods and structures according to this invention.
[0025] These and other features and advantages of the disclosed embodiments are described in, or are apparent from, the following detailed description of various exemplary embodiments of the systems, methods and structures according to this invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Various exemplary embodiments of the invention will be described in detail, with reference to the following figures, wherein
[0027] FIG. 1 illustrates a first exemplary embodiment of a fluid ejector carriage sweep path containment, and a fluid ejector carriage, usable with various exemplary embodiments of the systems, methods and structures according to this invention;
[0028] FIGS. 2 A-B illustrate a first exemplary embodiment of a fluid ejector carriage usable with various exemplary embodiments of the systems, methods and structures according to this invention;
[0029] FIG. 3 illustrates a bottom view of a first exemplary embodiment of a fluid ejector carriage usable with various exemplary embodiments of the systems, methods and structures according to this invention;
[0030] FIG. 4 illustrates a side view of a first exemplary embodiment of a fluid ejector carriage in a fluid ejector carriage sweep path containment usable with various exemplary embodiments of the systems, methods and structures according to this invention;
[0031] FIGS. 5 A-B are schematic diagrams illustrating a first exemplary embodiment of an airflow pattern to support mist removal from a fluid ejector carriage sweep path containment;
[0032] FIGS. 6 A-B are schematic diagrams illustrating a second exemplary embodiment of an airflow pattern to support mist removal from a fluid ejector carriage sweep path containment;
[0033] FIG. 7 illustrates a second exemplary embodiment of a fluid ejector carriage usable with various exemplary embodiments of the systems, methods and structures according to this invention;
[0034] FIG. 8 illustrates a bottom view of a second exemplary embodiment of a fluid ejector carriage usable with various exemplary embodiments of the systems, methods and structures according to this invention;
[0035] FIG. 9 illustrates a side view of a second exemplary embodiment of a fluid ejector carriage in a fluid ejector carriage sweep path containment usable with various exemplary embodiments of the systems, methods and structures according to this invention;
[0036] FIGS. 10 A-B are schematic diagrams illustrating a first exemplary embodiment of an airflow pattern to support fluid ejection element cooling through the fluid ejector carriage;
[0037] FIGS. 11 A-B are schematic diagrams illustrating a second exemplary embodiment of the airflow pattern to support fluid ejection element cooling through the fluid ejector carriage;
[0038] FIGS. 12 A-B are schematic diagrams illustrating a first exemplary embodiment of an airflow pattern to support drying the ejected fluid onto receiving medium;
[0039] FIG. 13 illustrates a side view of a third exemplary embodiment of a fluid ejector carriage in a fluid ejector carriage sweep path containment usable with various exemplary embodiments of the systems, methods and structures according to this invention; and
[0040] FIG. 14 illustrates a fourth exemplary embodiment of a fluid ejector carriage usable with various exemplary embodiments of the systems, methods and structures according to this invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0041] The following detailed description of various exemplary embodiments of the fluid ejector carriage sweep path containment and conforming fluid ejector carriage systems according to this invention may refer to and/or illustrate one specific type of fluid ejection system, an ink jet printer, for the sake of clarity and familiarity. However, it should be appreciated that the principles of this invention, as outlined and/or discussed below, can be equally applied to any known, or later-developed, fluid ejection system beyond the ink jet printer specifically discussed herein.
[0042] Various exemplary embodiments of the systems, methods and structures according to this invention enable the manipulation of airflow generated by fluid ejector carriage motion in devices, such as, for example, ink jet printers, copiers and/or facsimile machines, to at least one beneficial purpose. These beneficial purposes include: removing residual fluid mist generated in the fluid ejection process; cooling fluid ejector elements heated in the fluid ejection process; drying the fluid deposited on a receiving medium during the fluid ejection process; setting hot melt fluid deposited on a receiving medium during the fluid ejection process; and/or any other purpose wherein it would be advantageous to direct airflow created by the reciprocating motion of a fluid ejector carriage, such as, for example, to supplement or replace separate fans installed to induce airflow for such purpose.
[0043] In the various exemplary embodiments of the systems, methods and structures according to this invention, random airflow generated by fluid ejector carriage motion is contained and focused such that increased efficiency is gained with each sweep of the fluid ejector carriage within a fluid ejector carriage sweep path containment to accomplish one or more beneficial purposes. While 100% efficiency in movement and resultant manipulation of the airflow in the sweep path containment is not achievable, particularly in consideration of the requirement for access of the fluid ejection elements to the receiving medium, it is desirable to reduce random leakage from the fluid ejector carriage sweep path containment to the greatest extent. It is further desirable to maintain generally strict tolerances between the silhouette of the fluid ejector carriage and the internal faces of the fluid ejector carriage sweep path containment in order that, with each sweep of the fluid ejector carriage, a maximum percentage of the volume of the air contained within the fluid ejector sweep path containment is manipulated to at least one beneficial purpose. These tolerances, however, should not be designed, manufactured or molded so strictly to risk contact between the fluid ejector carriage and the internal surfaces of the fluid ejector carriage sweep path containment. Such contact would impede fluid ejector carriage motion, produce unintentional frictional drag, and/or generate unwanted noise within the fluid ejection device.
[0044] FIG. 1 illustrates a first exemplary embodiment of a fluid ejector carriage sweep path containment 100 , and a fluid ejector carriage 200 , usable with various exemplary embodiments of the systems, methods and structures according to this invention. As shown in FIG. 1 , the fluid ejector carriage sweep path containment 100 substantially encloses the fluid ejector carriage 200 and the structures upon which the fluid ejector carriage 200 translates, such as, for example, carriage guide rods and/or rails 250 , in a generally reciprocating motion.
[0045] In various exemplary embodiments of the systems, methods and structures according to this invention, the fluid ejector carriage sweep path containment 100 is formed from a plurality of individual elements which combine to substantially enclose the fluid ejector carriage 200 and structures upon which the fluid ejector translates. For simplicity, clarity and ease of explanation, the depicted embodiment of the fluid ejector carriage sweep path containment 100 is substantially a box-like containment structure that includes a bottom panel 110 , end panels 120 , a front panel 130 , a back panel 140 (removed in FIG. 1 ) and a fixed or movable top panel 150 . It should be appreciated that the fluid ejector carriage sweep path containment can be of any shape or size as long as the essential characteristic of generally maximum airflow manipulation is maintained. It should be appreciated further that the individual panel elements 110 / 120 / 130 / 140 / 150 , which combine to embody the fluid ejector carriage sweep path containment 100 , may be permanent or temporary, fixed or movable, individual elements. Additionally, the individual panel elements 110 / 120 / 130 / 140 / 150 may be molded individually into the structure of the housing of the fluid ejection device or secured to the internal structure of the fluid ejection device in various exemplary combinations.
[0046] In various exemplary embodiments of the systems, methods and structures according to this invention, at least one full-span slotted opening (not shown), as will be described below, usable to provide access for fluid ejection from the fluid ejector elements housed in the fluid ejector carriage 200 to the receiving medium, is included.
[0047] In various exemplary embodiments of the systems, methods and structures according to this invention, the motion of the fluid ejector carriage 200 , as it translates along at least one structure inside the fluid ejector carriage sweep path containment 100 , creates airflow that can be manipulated to beneficial purposes as described in detail below.
[0048] In the various exemplary embodiments of the systems, methods and structures according to this invention, openings 300 usable to facilitate desired airflow patterns are added. It should be appreciated that, though depicted in FIG. 1 as located in the end panels 120 , these openings can be located anywhere, generally at either end of the carriage sweep path, to facilitate desired airflow through and out of the fluid ejector carriage sweep path containment 100 . In various exemplary embodiments of the systems, methods and structures according to this invention, the openings 300 are completely unobstructed holes, or are in the form of vents with louvers, screen and/or other such structures added. As will be detailed below, the openings 300 may include filters usable to trap mist or other contaminants. Also, separate structures, such as, for example, channels, ducting, accordion-style bellows and/or other enclosures usable to direct exhaust air to specific areas inside or outside the fluid ejection device may be added.
[0049] FIGS. 2 A-B illustrate a first exemplary embodiment of a fluid ejector carriage 200 usable with various exemplary embodiments of the systems, methods and structures according to this invention. As shown in FIG. 2 , the fluid ejector carriage 200 includes a receiving area 210 to house the elements of at least one fluid ejection system. In various exemplary embodiments of the systems, methods and structures according to this invention, fluid ejection elements are mounted to a platform 215 . The fluid ejector carriage 200 also includes at least one housing 220 which houses at least one interface structure to provide interface between the fluid ejector carriage and the structure upon which the fluid ejector carriage translates. In cases where these structures are guide rods, the interface structures are then referred to and depicted, in exemplary manner, as fluid ejector carriage rod guides 225 . While depicted in FIG. 2 as a single separate housing 220 , it should be appreciated that the housing 220 need not be a separate compartment internal to the fluid ejector carriage 200 . Rather, any structure to facilitate passage of at least one structure upon which fluid ejector carriage translates (not shown) through the fluid ejector carriage 200 , while leaving generally intact the silhouette of the sides of the fluid ejector carriage 200 such that they conform to the overall cross-sectional size and shape of the inside of the fluid ejector carriage sweep path containment, depicted in FIG. 1 as element 100 , may be included.
[0050] In various exemplary embodiments of the systems, methods and structures according to this invention, the fluid ejector carriage 200 has a top face 230 , a front face 232 , a rear face 234 , side faces 236 and 238 , and a bottom face 240 . It should be appreciated that the side faces 236 and 238 are necessary to the operation of the invention as described herein. These side faces 236 and 238 conform in silhouette, shape and size to the internal cross-section of the fluid ejector carriage sweep path containment 100 . In various exemplary embodiments of the systems, methods and structures according to this invention, faces 230 , 232 , 234 and 240 may be present or absent as fixed or movable structures as are necessary for the structural integrity of the fluid ejector carriage 200 , or for securing the fluid ejection elements therein, while providing access for servicing and/or replacement of these elements in the fluid ejector carriage 200 .
[0051] FIG. 3 illustrates a bottom view of a first exemplary embodiment of a fluid ejector carriage 200 usable with various exemplary embodiments of the systems, methods and structures according to this invention. As shown in FIG. 3 , the fluid ejector carriage 200 is mounted on at least one structure upon which the fluid ejector carriage translates, such as, for example, at least one fluid ejector carriage guide rod 250 and between front and back panels 130 and 140 of the fluid ejector carriage sweep path containment 100 (depicted in FIG. 1 ). At least one fluid ejector element 265 (enlarged for clarity) is mounted on a face of the fluid ejector carriage 200 to deposit fluid on a receiving medium (not shown) as the fluid ejector carriage 200 translates along the at least one fluid ejector carriage guide rod 250 in direction A. It should be appreciated that, though depicted in FIG. 3 as mounted on the bottom face 240 of the fluid ejector carriage, the fluid ejector element 265 could be mounted on, or integral to, any face, front, top, bottom, or back of the fluid ejector carriage 200 that would facilitate access through the corresponding front, top, bottom, or back of the fluid ejector carriage sweep path containment 100 to accomplish fluid ejection from the fluid ejector element 265 onto the receiving medium.
[0052] In various exemplary embodiments of the systems, methods and structures according to this invention, the gap between the fluid ejector carriage 200 and the internal faces of the fluid ejector carriage sweep path containment, represented in FIG. 3 by the front panel 130 and the back panel 140 , is generally minimized to promote nearly complete airflow manipulation, minimizing leakage around the fluid ejector carriage 200 , as the fluid ejector carriage 200 translates along the at least one fluid ejector carriage guide rod 250 in direction A.
[0053] FIG. 4 illustrates a side view of a first exemplary embodiment of a fluid ejector carriage 200 in a fluid ejector carriage sweep path containment usable with various exemplary embodiments of the systems, methods and structures according to this invention. As shown in FIG. 4 , the fluid ejector carriage 200 is surrounded by the panels 110 , 130 , 140 and 150 of the fluid ejector carriage sweep path containment. The gap between the internal faces of the fluid ejector carriage sweep path containment panels 110 / 130 / 140 / 150 and the fluid ejector carriage 200 is generally minimized on all sides to facilitate as complete airflow movement on either side of, and to minimize leakage past, the fluid ejector carriage 200 as the fluid ejector carriage 200 translates along the at least one structure or fluid ejector carriage guide rod 250 depicted in FIG. 3 .
[0054] In the various exemplary embodiments of the systems, methods and structures according to this invention, the side faces 236 / 238 of the fluid ejector carriage 200 , conforming in size and shape to the internal cross-sectional area of the fluid ejector carriage sweep path containment, are solid to facilitate the manipulation of the air within the fluid ejector carriage sweep path containment completely external to the fluid ejector carriage 200 , as will be described below. It should be appreciated that, although depicted for simplicity and clarity as having a generally rectangular silhouette, the silhouette of the fluid ejector carriage 200 could embody any simple or complex shape, or combination of shapes, and may include at least one protrusion or extension as a structure to facilitate alignment of the fluid ejector carriage in the fluid ejector carriage sweep path containment. For example, see the complex shape illustrated in FIG. 13 . In the various exemplary embodiments of the systems, methods and structures according to this invention, the plurality of panels or structures which combine to form the fluid ejector carriage sweep path containment are molded or manufactured such that the internal surfaces of the plurality of panels substantially enclose a volume with a cross-sectional area that conforms in shape and is slightly larger in size than the simple or complex silhouette of the side faces 236 / 238 of the fluid ejector carriage.
[0055] In the various exemplary embodiments of the systems, methods and structures according to this invention, a slot 115 is included to provide access for the fluid ejector element 265 to the receiving medium 500 . The slot 115 generally traverses the entire length of a face, for example, the bottom face 110 as depicted in FIG. 4 , of the fluid ejector carriage sweep path containment. The receiving medium 500 is separately moved past the fluid ejector carriage sweep path containment in a direction generally perpendicular to the motion of the fluid ejector carriage 200 such that, with each successive sweep of the fluid ejector carriage 200 along the at least one fluid ejector carriage guide rod 250 (depicted in FIG. 3 ), fluid is ejected in a plurality of generally parallel lines or fields onto the receiving medium 500 . It should be appreciated that, though depicted in FIG. 4 as being mounted on the bottom face of the fluid ejector carriage 200 , the fluid ejector element 265 necessary for ejecting fluid onto the receiving medium may be mounted on, or integrally into, any face, front, top, bottom or back, of the fluid ejector carriage 200 . The slot 115 which provides access for the fluid ejector element 265 to the receiving medium 500 is present in corresponding position on the fluid ejector carriage sweep path containment.
[0056] The width of the slot 115 which provides access for the fluid ejector element 265 to the receiving medium 500 does provide the opportunity for leakage of the manipulated airflow based on carriage motion from the fluid ejector carriage sweep path containment. This leakage is, however, minimized as the receiving medium 500 provides a boundary that effectively closes the slot 115 in the bottom face 110 . It should be appreciated that, in conventional systems, fluid throw distance from a fluid ejector element to a receiving medium is generally about 2.5 mm or less. The slight gap between the open face 110 of the fluid ejector carriage sweep path containment 100 and the receiving medium 500 results in the receiving medium effectively acting as the airflow boundary to contain the manipulated airflow produced by carriage motion on this side of the fluid ejector sweep path containment 100 .
[0057] FIGS. 5 A-B are schematic diagrams illustrating a first exemplary embodiment of the airflow pattern to support mist removal from the fluid ejector carriage sweep path containment 100 . As the fluid ejector carriage 200 translates along at least one structure (not shown) inside the fluid ejector carriage sweep path containment 100 in direction X, air is drawn in through opening 300 into the airflow zone R and is expelled through opening 300 from airflow zone S in the direction shown by the arrows in FIG. 5A . As fluid is ejected by the fluid ejection system onto the receiving medium, residual droplets are formed and trail the fluid ejector carriage 200 in the area of the intake airflow zone R. When fluid ejector carriage motion is reversed, on subsequent sweep in direction Y, the airflow direction in airflow zones R and S reverse, as shown by the arrows in FIG. 5B . As fluid is ejected onto the receiving medium, residual droplets are created and trail the carriage in airflow zone S. The residual fluid mist droplets created on prior sweeps are forcibly expelled by the airflow in airflow zone R through opening 300 before they have a chance to settle on any of the internal structures or surfaces of the fluid ejector sweep path containment.
[0058] FIGS. 6 A-B are schematic diagrams illustrating a second exemplary embodiment of the airflow pattern to support mist removal from the fluid ejector carriage sweep path containment 100 . Optional filters 600 are introduced in proximity to the openings 300 . As the fluid ejector carriage 200 translates along at least one structure (not shown) inside the fluid ejector carriage sweep path containment 100 in direction X, air is drawn in through opening 300 into the airflow zone R and is expelled through opening 300 from airflow zone S in the direction shown by the arrows in FIG. 6A . When carriage motion is reversed, on subsequent sweep in direction Y, the airflow direction in airflow zones R and S reverses, as shown by the arrows in FIG. 6B . The residual fluid mist droplets created are forcibly expelled in the fluid ejection process by the airflow motion on subsequent sweeps, through filter 600 and opening 300 before the mist droplets settle on any internal structure or surface of the fluid ejector sweep path containment. The addition of fluid mist filters 600 , while restricting airflow to some extent, has the advantage that on subsequent sweeps in directions X and Y the fluid mist droplets are generally captured and managed by the filters 600 rather than being freely or completely exhausted out through openings 300 .
[0059] FIG. 7 illustrates a second exemplary embodiment of a fluid ejector carriage usable with various exemplary embodiments of the systems, methods and structures according to this invention. Openings 400 are added in the side faces 236 / 238 of the fluid ejector carriage 200 , and in any structures that may be added so that the silhouette of the carriage approximates the cross-sectional area of the inside of the fluid ejector carriage sweep path containment. These openings facilitate airflow movement through the fluid ejector carriage 200 , as will be described in detail below. In various exemplary embodiments of the systems, methods and structures according to this invention, the openings 400 are completely unobstructed holes in the sides of the carriage, or are in the form of vents with louvers, screen and/or other such structures added. The openings 400 may include filters usable to trap mist or other contaminants. The openings 400 are added to facilitate manipulation of a percentage of the resultant airflow, based on fluid ejector carriage motion, through the fluid ejector carriage 200 .
[0060] FIG. 8 illustrates a bottom view of a second exemplary embodiment of a fluid ejector carriage 200 usable with various exemplary embodiments of the systems, methods and structures according to this invention. FIG. 9 illustrates a side view of a second exemplary embodiment of a fluid ejector carriage 200 in a fluid ejector carriage sweep path containment. As shown in FIGS. 8 and 9 , the fluid ejector carriage 200 is mounted on at least one structure along which the carriage translates such as, for example, a fluid ejector carriage guide rod 250 and between the front and back panels 130 / 140 of the fluid ejector carriage sweep path containment 100 (depicted in FIG. 1 ).
[0061] In various exemplary embodiments of the systems, methods and structures according to this invention, at least one structure or device 275 usable to manipulate the resultant airflow that passes through the fluid ejector carriage 200 through the side openings 400 (depicted in FIG. 7 ) is added. The at least one structure and/or device 275 directs the resultant airflow, generated by fluid ejector carriage motion in direction A, across the heater elements of the fluid ejection module and heat sinks, if installed, to dissipate the heat generated by the fluid ejection operation.
[0062] FIGS. 10 A-B are schematic diagrams illustrating a first exemplary embodiment of the airflow pattern to support fluid ejector element and/or heat sink cooling through the fluid ejector carriage 200 . As the fluid ejector carriage 200 translates along at least one structure (not shown) inside the fluid ejector carriage sweep path containment 100 in direction X air is drawn in through opening 300 into airflow zone R and expelled through opening 300 from airflow zone S in the direction shown by the arrows in FIG. 10A . A percentage of the air inside the fluid ejector carriage sweep path containment 100 passes through the fluid ejector carriage 200 in resultant direction V. This airflow is manipulated by one or more structures and/or devices 275 (depicted in FIG. 8 ) across the heater elements of the fluid ejector module and heat sinks, if installed, housed in the fluid ejector carriage 200 , to dissipate heat. When fluid ejector carriage motion is reversed on a subsequent sweep in direction Y, airflow direction in airflow zones R and S reverse, as shown by the arrows in FIG. 10B . Heated air that remained in airflow zone R based on the resultant airflow V from the previous sweep is then expelled from airflow zone R while resultant airflow W in FIG. 10B is directed through the fluid ejector carriage 200 to continue the cooling process.
[0063] FIGS. 11 A-B are schematic diagrams illustrating a second exemplary embodiment of the airflow pattern to support fluid ejector element and/or heat sink cooling through the fluid ejector carriage 200 . As shown in FIG. 11A , optional louvers 700 are introduced.
[0064] In the various exemplary embodiments of the systems, methods and structures according to this invention, the percentage of the resultant airflow generated by fluid ejector carriage 200 movement in the fluid ejector carriage sweep path containment 100 that is available for fluid ejector element and/or heat sink cooling is dependent on the size of the openings 400 in the side of the fluid ejector carriage 200 and constriction of exhaust air from the fluid ejector carriage sweep path containment 100 . Constriction of exhaust air can be accomplished by: decreasing the size of the openings 300 in the ends of the fluid ejector carriage sweep path containment 100 ; increasing the density of the filter elements 600 , depicted in FIG. 6 ; introducing one-way air vents and/or louvers 700 A and B; or, if airflow across the fluid ejector elements and/or heat sink is the only objective, doing away with the openings 300 altogether, resulting in substantially closed ends to the fluid ejector carriage sweep path containment 100 .
[0065] In the exemplary embodiment of this invention depicted in FIGS. 11 A-B, as the fluid ejector carriage 200 translates along at least one structure (not shown) inside the fluid ejector carriage sweep path containment 100 in direction X, air is drawn in through the open louvers 700 , in proximity to opening 300 , into airflow zone R and exhausted from airflow zone S through louvers 700 . A portion of the resultant airflow generated by the fluid ejector carriage motion is forced through the opening in the fluid ejector carriage 200 in the direction depicted by the arrow V in FIG. 11A . When fluid ejector carriage motion is reversed, on a subsequent sweep in direction Y, the airflow patterns in airflow zones R and S stop when the louvers 700 close, as shown in FIG. 11B . Motion of the fluid ejector carriage 200 in direction Y causes air in airflow zone R in front of the fluid ejector carriage, restricted by the closed louvers, from being exhausted, to be reversed such that a larger percentage of the airflow is forced through the openings in the fluid ejector carriage 200 in the resultant direction W, as depicted in FIG. 11B .
[0066] FIGS. 12 A-B are schematic diagrams illustrating a first exemplary embodiment of an airflow pattern to support drying and/or setting of the fluid ejected onto a receiving medium. In the various exemplary embodiments of the systems, methods and structures according to this invention, the fully closed carriage depicted in FIGS. 3 and 4 facilitates drying/setting of the fluid deposited on the receiving medium as a portion of the airflow in front of the carriage as it translates along at least one structure will be sheared across the face of the receiving medium based on the piston like effect of the carriage and the fact that the face of the fluid ejector sweep path containment adjacent to the receiving medium is essentially open such that the airflow generated by the carriage motion is not restricted by the structure of the face but rather by the presence of the receiving medium. As the fluid ejector carriage 200 translates along at least one structure (not shown) inside the fluid ejector carriage sweep path containment 100 in direction X, air is drawn in through opening 300 into airflow zone R. Based on constriction in the exit side opening, a portion of the resultant airflow V which meets the face of the fluid ejector carriage 200 is deflected generally in the direction of the receiving medium 500 as shown in FIG. 12A . When fluid ejector carriage 200 motion is reversed, on a subsequent sweep in direction Y, airflow direction in airflow zones R and S reverses, as shown in FIG. 12B , the process of fluid drying/setting continues with each subsequent sweep and the directing of a portion of the resultant airflow toward the receiving medium 500 .
[0067] In the various exemplary embodiments of the systems, methods and structures according to this invention, enlarging the span-wise slot in the side of the fluid ejector sweep path containment that faces the receiving medium, specifically in the direction that the receiving medium translates, can further facilitate the process of drying/setting fluid deposited on the receiving medium.
[0068] FIG. 13 illustrates a side view of a third exemplary embodiment of a fluid ejector carriage in a fluid ejector carriage sweep path containment usable with various exemplary embodiments of the systems, methods and structures according to this invention. As shown in FIG. 13 , the fluid ejector carriage 200 is surrounded by a bottom panel 110 , a front panel 130 , a back panel 140 , and a movable top panel 150 . The movable top panel 150 facilitates access to the fluid ejector carriage 200 , for example, when opened in direction C. Movable top panel 150 may be provided with any conventional or subsequently developed removable mounting structure, such as a hinge or a fully removable mount so as to provide access to the sweep path for maintenance, repair or other purpose. It should be appreciated that any of the panels or combinations of panels may be removably provided to facilitate access to the fluid ejector carriage 200 or sweep path.
[0069] In the exemplary embodiment depicted in FIG. 13 , the fluid ejector carriage 200 includes a structural interface such as a fluid ejector carriage rod guide 225 to accommodate a structure upon which the fluid ejector carriage translates such as, for example, a fluid ejector carriage guide rod (not shown). The side panels 236 / 238 of the fluid ejector carriage 200 have a complex shape which substantially conforms to the internal cross-sectional shape of the fluid ejector carriage sweep path containment 100 comprising the fluid ejector carriage sweep path containment panels 110 / 130 / 140 / 150 . In the exemplary embodiment shown in FIG. 13 , the fluid ejector element 265 is mounted on the bottom face of the fluid ejector carriage 200 . The fluid ejector carriage sweep path containment 100 provides an opening 115 in the bottom panel 110 to facilitate access of the fluid ejector element 265 to the receiving medium 500 .
[0070] In the exemplary embodiment depicted in FIG. 13 , the gap between the internal faces of the fluid ejector carriage sweep path containment panels 110 / 130 / 140 / 150 and the fluid ejector carriage 200 is generally minimized to facilitate as complete air flow movement on either side of, and to minimize leakage past, the fluid ejector carriage 200 as the fluid ejector carriage 200 translates along the at least one structure. It should be appreciated that the silhouette of the fluid ejector carriage 200 could embody any simple or complex shape or combination of shapes, and may include at least one protrusion or extension as a structure to facilitate alignment of the fluid ejector carriage 200 in the fluid ejector carriage sweep path containment 100 .
[0071] FIG. 14 illustrates a fourth exemplary embodiment of a fluid ejector carriage usable with various exemplary embodiments of the systems, methods and structures according to this invention. As depicted in FIG. 14 , structures 910 and 920 are added to the sides of the fluid ejector carriage 200 . These structures 910 and 920 are manipulated, shaped and/or enlarged to fit the cross-sectional silhouette of the fluid ejector carriage sweep path containment. Such structures 910 and 920 include, but are not limited to, simple lightweight baffles specifically designed to mirror the cross-sectional shape and size of the inside of the fluid ejector carriage sweep path containment. For simplicity, clarity and ease of depiction, the structures 910 and 920 depicted in FIG. 14 are generally rectangular. It should be appreciated that these structures 910 and 920 can be of any simple or complex shape, and an appropriate size, as long as the essential characteristic of generally promoting maximum airflow manipulation within the fluid ejector sweep path containment is maintained.
[0072] In the various exemplary embodiments of the systems, methods and structures according to this invention, at least one non-fluid ejection sweep of the fluid ejector carriage in the fluid ejector carriage sweep path containment may be added to the end of, or interleaved throughout, the fluid ejection process to facilitate: better mist removal and control; additional fluid ejection device cooling; and/or improved drying/setting of all lines or fields of fluid deposited on the receiving medium.
[0073] While this invention has been described in conjunction with the exemplary embodiments outlined above, various alternatives, modifications, variations, and/or improvements, whether known or that are, or may be, presently unforeseen, may become apparent. Accordingly, the exemplary embodiments of the invention, as set forth above, are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and/or scope of the invention. Therefore, the systems, methods, structures and/or devices according to this invention are intended to embrace all known, or later-developed alternatives, modifications, variations, and/or improvements. | A system, method and structure that promotes removing mist, dissipating heat, and/or drying a receiving medium in a fluid ejection device. This is achieved by substantially enclosing the sweep path of the fluid ejector carriage and manipulating the generally enclosed airflow that results from translating the fluid ejector carriage in a sweep direction. | 47,066 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority of U.S. provisional applications No. 60/330,689 filed on Oct. 29, 2001 and No. 60/333,753 filed on Nov. 29, 2001.
FIELD OF THE INVENTION
[0002] The present invention relates to a simulation system, a simulation method and a computer-readable medium for analysis, and synthesis of human motion under partial assist from powered augmentation devices.
BACKGROUND OF THE INVENTION
[0003] Effective usage of human assistive systems or augmentation devices for restoration or enhancement of motor function is an important area of research in rehabilitation and performance enhancement. A partial list of important and desired features of an effective assistive system include: (1) a decrease in energy rate and cost with respect to able-bodied subjects performing the same task, (2) minimum disruption and maximum comfort of normal activities when employing the assistive system, and (3) practicality.
[0004] The third requirement considers the ease of wearing such a device and its power consumption needs. These requirements and available technology have led to the development of externally powered orthoses and prostheses that interface directly or indirectly with the human neuromuscular system. Although significant progress has been made in meeting many of the requirements needed for development of practical human assist devices (Popovic, D., Externally Powered and Controlled Orthotics and Prosthetics. The Biomedical Engineering Handbook, Editor Bronzino, J. D., 2nd ed. Vol. 2, Chapter 142, 2000), realization of such systems for daily applications is still in its infancy. The complexity of the central nervous system (CNS) control and the interface between voluntary control and external artificial control are still challenging, unanswered questions.
[0005] At Honda's Wako Research Center, a mechanically powered walking assist prototype system was recently unveiled (Katoh and Hirata, The Concept of a Walking Assistance Suit, Welfare Engineering Symposium, The Japan Society of Mechanical Engineers, August 2001). The target application is to help the elderly and disabled people to either execute daily tasks they could not previously perform, or use less physical exertion than they currently employ for these tasks. The tasks considered include walking, lifting, sitting/standing, and climbing stairs. Two important and challenging questions to consider in the implementation of the Honda prototype and similar human augmentation systems include: 1) analysis and monitoring of biomechanical as well as physiological quantities which cannot be readily measured and 2) the synthesis of an active control which can safely and effectively augment voluntary control. By developing computational methods to study these issues, future performance of human augmentation devices can be studied through simulation, without constraints imposed by hardware implementations of current technology. Simulation studies also enable us to estimate physiological quantities that cannot be easily measured, including muscle forces, joint forces, and energetics of motion. We can simulate effects of aging, predict muscular activity, estimate muscle fatigue and capacity, and detect potential dangerous physiological conditions. It should be mentioned that the exclusive use of simulation is not a substitute for eventual testing on live human subjects. However, an accurate subject-specific simulation allows control algorithms to be designed and refined for the walking assist device. This is especially relevant in our target user population because they already have existing health constraints.
[0006] U.S. Pat. No. 6,152,890 discloses a device and a method for the recording, presentation and automatic classification of biomechanical variables measured on a freely moving test person during a work shift.
[0007] Japanese patent publication unexamined No. 2000-249570 discloses a method for generating human kinematic data.
[0008] “Gruber, K. et. al., 1998. A comparative study of impact dynamics: wobbling mass model versus rigid body models. Journal of Biomechanics 31, 439-444” discloses inverse dynamics model used to simulate the human body.
[0009] However, any of the above documents does not deal with analysis and synthesis of human motion under assist from powered augmentation devices.
[0010] Accordingly, what is needed is a system and a method for analysis and synthesis of human motion under assist from powered augmentation devices.
SUMMARY OF THE INVENTION
[0011] According to one aspect of the invention, a simulation system is provided for a combined musculoskeletal and augmentation device system including segments and joints connecting the segments. The simulation system comprises a dynamics model of the combined musculoskeletal and augmentation device system and an augmentation device controller for control of the augmentation device. The simulation system further comprises an inverse dynamics model for the musculoskeletal and augmentation device system and a muscle force and muscle capacity module for checking and adjusting the computed torques. The dynamics model of the combined musculoskeletal and augmentation device system receives feasible computed torques at the joints as inputs and delivers simulated kinematic data of the segments as outputs. The augmentation device controller for control of the augmentation device, receives the simulated kinematic data as inputs and delivers assist torques as outputs. The inverse dynamics model for the musculoskeletal and augmentation device system, receives the simulated kinematic data, desired kinematic data of the segments and the assist torques as inputs and delivers the computed muscle torques and net joint torque as outputs. The muscle force and muscle capacity module for checking and adjusting the computed torques, receives the computed muscle torques as inputs and delivers feasible computed torques as outputs after making adjustments to the computed torques.
[0012] According to another aspect of the invention, a method is provided for simulating a combined musculoskeletal and augmentation device system including segments and joints connecting the segments. The method comprises the steps of computing assist torques of the augmentation device, based on simulated kinematic data and computing torques based on the simulated kinematic data, desired kinematic data of the segments and the assist torques. The method further comprises the steps of checking and adjusting the computed torques and computing the simulated kinematic data of the segments based on the computed torques at the joints.
[0013] According to another aspect of the invention, a computer readable medium containing a program for simulating a combined musculoskeletal and augmentation device system including segments and joints connecting the segments, is provided. The program comprises instructions of computing assist torques of the augmentation device, based on simulated kinematic data and of computing torques based on the simulated kinematic data, desired kinematic data of the segments, and the assist torques. The program further comprises instructions of checking and adjusting the computed torques and of computing the simulated kinematic data of the segments based on computed torques at the joints.
[0014] According to an embodiment of the invention, muscle forces are deduced from the computed torques, compared with maximum force limits and adjusted if the muscle forces exceed limits, to obtain feasible torques.
[0015] According to another embodiment of the invention, muscle forces with and without the assist torques are compared in order to asses whether the assist torque control helps or hinders motion and if the assist torque control hinders motion the muscle forces are adjusted and feasible joint torques are computed.
[0016] According to another embodiment of the invention, muscle forces with and without the assist torques are compared in order to asses whether the assist torque control helps or hinders motion and if the assist torque control hinders motion the assist torque control law is adjusted to ensure that feasible joint torques are computed.
[0017] According to another embodiment of the invention, muscle forces are deduced based on a static optimization criterion in which a sum of muscle activation squared is minimized.
[0018] According to another embodiment of the invention, modified accelerations of kinematic data are obtained through non-linear position and velocity feedback from the simulated kinematic data.
[0019] According to another embodiment of the invention, the kinematic data include position data, velocity data and acceleration data and estimates of kinematic data are computed, through non-linear feedback based on desired acceleration data, error between simulated position data and desired position data and error between simulated velocity data and desired velocity data.
[0020] According to another embodiment of the invention, the kinematic data include position data, velocity data and acceleration data and estimates of kinematic data are computed, through non-linear feedback based on error between simulated position data and desired position data and/or error between simulated velocity data and desired velocity data.
[0021] According to another embodiment of the invention, computed reaction forces under the segments contacting the ground are obtained based on the feasible computed torques and the simulated kinematic data.
[0022] According to another embodiment of the invention, gravity compensation control algorithm is employed, in which the assist torques are obtained to reduce the computed muscle force by artificially compensating for the forces due to gravity.
[0023] According to another embodiment of the invention, change in the computed torques, due to compensation for gravity is obtained, using coordinates of the center of the mass of the segments.
[0024] According to another embodiment of the invention, the coordinates of the center of the mass of the segments, are obtained from measurements of joint angles and segment lengths.
[0025] According to another embodiment of the invention, change in the computed torques, due to compensation for gravity, is obtained using measured reaction forces under the feet.
[0026] According to another embodiment of the invention, the feedback gains are selected to produce the fastest possible non-oscillatory response.
DESCRIPTION OF THE DRAWINGS
[0027] [0027]FIG. 1 a biped system having five degrees of freedom in the sagittal plane with intermittent ground contact during double support, single support, and air-born phase;
[0028] [0028]FIG. 2 is a system model description with intermittent contact of left and right feet with the ground;
[0029] [0029]FIG. 3 is an inverse dynamics controller with position and velocity feedback for calculation of torques that when applied to a system model, will track and reproduce the desired kinematic data;
[0030] [0030]FIG. 4 is a muscle force and muscle capacity module;
[0031] [0031]FIG. 5 is a block-diagram of the integrated simulation system;
[0032] [0032]FIG. 6 is a flowchart illustrating a simulation process according to an aspect of the present invention;
[0033] [0033]FIG. 7 is a simulation of the joint angles during a squatting maneuver without employing the desired accelerations (a=0), in which nearly perfect tracking of desired kinematic trajectories is illustrated;
[0034] [0034]FIG. 8 is a simulation of the joint torques during a squatting maneuver without employing the desired accelerations (a=0), in which the proposed method using nonlinear feedback (NLF) produces nearly identical joint torque estimates as compared to the ground truth (ideal) joint torques obtained by a noise free inverse dynamics computation; and
[0035] [0035]FIG. 9 is a simulation of the horizontal and vertical ground reaction forces during a squatting maneuver without employing the desired accelerations (a=0), in which the proposed method using nonlinear feedback (NLF) produces nearly identical ground reaction estimates as compared to the ground truth (ideal) ground reaction forces obtained by an Iterative Newton Euler inverse dynamics procedure.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0036] The present invention provides computational methods for analysis, and synthesis of human motion under partial assist from powered augmentation devices. The algorithms are integrated in a simulation platform to be used as a test-bed for prototyping, simulating, and verifying algorithms to control human motion under artificial control. The analysis and synthesis problems in human motion are formulated as a trajectory tracking control algorithm using inverse and forward models coupled by proportional and derivative feedback terms. A muscle force distribution and capacity module is used to monitor the computed joint torques in order to assess the physiological consequences of the artificial control, and if needed to make modifications. This framework allows us to verify robustness, stability, and performance of the controller, and to be able to quickly change parameters in a simulation environment. We can study many different motions in a simulation environment. Thus, future performance and designs of human augmentation devices can be studied through simulation, without the risk and constraints imposed by hardware implementations of current technology.
[0037] The System Model
[0038] The system (or plant) refers to a dynamic model of the combined musculoskeletal and augmentation device system. The system may be designed having various degrees of complexity, depending on the requirements imposed by the study. Without loss of generality, we consider a simple planar biped system to illustrate the concepts (See FIG. 1). The equations of motion are formulated in such a way to handle three phases of biped motion as shown in FIG. 1. They include single support, double support, and airborn. Let q be the coordinates corresponding to the rotational and translational degrees of freedom.
q=[x 3 y 3 Θ 1 Θ 2 Θ 3 Θ 4 Θ 5 ] T (1)
[0039] where (x 3 , y 3 ) corresponds to the center of mass of the torso and the joint angles Θ are measured clockwise from the vertical.
[0040] The system is actuated by voluntary control from the muscles and artificial control from the augmentation device. The total torque applied at the joints (net joint torque) are the combined torque from the muscles (τ m ) and the assist actuators (τ a )
τ=τ a +τ m (2)
[0041] Let C(q) represent the foot-floor contact constraints and Γ=[Γ L Γ R ] T be the vector corresponding to the ground reaction forces under the left and right feet. The equations of motion of the system are given by,
J ( q ) q ¨ + B ( q , q . ) q . + G ( q ) + T ad = ∂ C T ∂ q Γ ′ + D τ ( 3 )
[0042] where J, B, and G correspond to the inertia, coriolis and centrifugal torques, and gravitational terms, respectively. The vector T ad models the augmentation device dynamics and the constant matrix D characterizes the torque coupling effects at the joints. The matrix D is present because absolute coordinates for the joint angles are used in the formulation of the equation of motion, as opposed to relative coordinates. The ground reaction forces may be expressed as a function of the state and inputs by (Hemami, H., A feedback On-Off Model of Biped Dynamics. IEEE Transactions on Systems, Man, and Cybernetics, Vol. SMC-10, No. 7, July 1980).
Γ = ( ∂ C ∂ q J ( q ) - 1 ∂ C T ∂ q ) - 1 ( - ∂ ∂ q ( ∂ C ∂ q q . ) q . + ∂ C ∂ q J ( q ) - 1 ( B ( q , q . ) q . + G ( q ) + T ad - D τ ) ) ( 4 )
[0043] [0043]FIG. 2 shows a system model description with intermittent contact of left and right feet with the ground. Forward dynamic simulations are performed by computing the induced accelerations {umlaut over (q)} obtained from Equation 3 and Equation 4, using the simulated state variable q and {dot over (q)} which are obtained by numerical integration.
[0044] The Internal (Inverse) Model
[0045] It has been demonstrated that the behavior of the human body when coupled with a novel mechanical system is very similar to the behavior that results when the controller relies on an internal model. One such internal model is thought to be a forward model, a term used to describe the computations involved in predicting sensory consequences of a motor command. There are a number of studies that have suggested that a forward model may be used by the human central nervous system (CNS) to estimate sensory consequences of motor actions (Wolpert, D. M., Miall, R. C., Kerr, G. K., Stein, J. F. Ocular limit cycles induced by delayed retinal feedback. Exp Brain Res., 96: 173-180, 1993; Flanagan. J. R., Wing, A. M. The role of internal models in motion planning and control: evidence from grip force adjustment during movements of hand held loads. J. Neurosci, 17:1519-1528, 1997). This theory is easily understood when considering transmission delays inherent in the sensory-motor loop. Although a forward model is particularly relevant to feedback control of time delayed systems, an inverse model is sometimes considered to predict the motor commands that are appropriate for a desired behavior (Atkeson, C. G. Learning arm kinematics and dynamics. Annu Rev. Neurosci, 12:157-183, 1989; Kawato, M., Adaptation and learning in control of voluntary movement by the central nervous system. Advanced Robotics 3, 229-249, 1989; Shadmehr, R., Leaming virtual equilibrium trajectories for control of a robot arm. Neural Comput, 2:436-477, 1990; Gomi, H., Kawato, M., The cerebellum and vor/okr learning models. Trends Neurosci, 15:445-453, 1992).
[0046] Inverse models are generally not considered for control of time delayed systems since the controller would seem to not have the ability to respond to the error and results in instability. However, it is plausible that local or intrinsic feedback mechanisms in conjunction with an inverse model can function to stabilize a system with latencies. Local feedback with stabilizing characteristics is believed to exist in humans in the form of viscoelastic properties of muscles and spinal reflex loop. The concept of an inverse model is also attractive for analysis problems of biomechanical quantities, whereby internal loads are estimated from kinesiological measurements. The approach adopted here in developing a computational model of human sensory motor control is based on the concept of an inverse model coupled with nonlinear feedback (FIG. 3). This mechanism is compelling from the standpoint of biomechanical analysis of human motion as well as the synthesis of artificial control. Let q d represent the desired kinematics, obtained from motion capture data. The following control law (Dτ′), when applied to the system equations, will result in a simulated response that will track and reproduce the desired kinematics data,
D τ ′ = J ( q ) q ¨ * + B ( q , q . ) q . + G ( q ) + T ad - ∂ C T ∂ q Γ ′ ( 5 )
[0047] where,
{umlaut over (q)}*=a{umlaut over (q)} d +K p ( q d −q )+ K v ( {dot over (q)} d −{dot over (q)} ) (6)
[0048] The diagonal matrices K p and K v represent the position and velocity feedback gains, respectively. The eigenvalues of the closed loop system are related to the feedback gains by the following,
K p =−(λ 1 +λ 2 ) (7)
K v λ 1 λ 2 (8)
[0049] A critically damped response (fastest possible non-oscillatory response) to the tracking error can be achieved by specifying the eigenvalues to be equal, real, and negative. The parameter a is constant and set to 0 or 1, depending on the severity of noise in the measurements. If the desired trajectories are obtained from noisy motion capture measurements, it may be appropriate to set a=0 and to specify the eigenvalues to be large and negative. This way, tracking is achieved without the need to compute unreliable accelerations from noisy kinematics data.
[0050] Muscle Force and Muscle Capacity
[0051] The muscle force and muscle capacity module should ideally be implemented in the forward path of the closed loop system (as shown in FIG. 5). However, it may also be implemented as a separate module whose output is used for analysis purpose only. In the latter case, the module's inputs would tap into the required variables of the closed loop system, but the module would not alter the closed loop dynamics.
[0052] In either case, a number of different muscle force distribution algorithms may be implemented. The underlying concepts of our choice of muscle force distribution algorithm is presented below.
[0053] The relationship between the net muscular moment τ m and the muscle forces F m is given by,
D τ m = - ∂ L T ∂ q F m ( 9 )
[0054] where L is the overall length of the muscle actuator, and ∂L T /∂q is an (n×m) muscle moment arm matrix. Since the number of muscles (m) exceeds the degrees of freedom (n), the computation of the muscle actuator's excitation inputs (and the resulting forces) from an inverse dynamics computation amounts to solving a problem that is inherently ill-posed. Static, nonlinear optimization has been used extensively to predict the individual muscle forces to produce the required torque. There are several compelling reasons for using static optimization to predict the individual muscle forces: first, static, non-linear optimization techniques have well developed theoretical foundations. With the advance of commercial software for solving general, constrained, multi-variable non-linear optimization problems, it is now possible to solve sophisticated problems numerically in relatively short time. Second, the notion that muscle forces are controlled in some way to optimize physiological criteria has great intuitive appeal. It has been shown that for motions like walking, static optimization yields very similar results to dynamic optimization (Anderson, F C and Pandy, M G., Static and Dynamic Optimization Solutions for Gait are practically equivalent, Journal of Biomechanics 34, 2001, 153-161, 2001).
[0055] A muscle force and muscle capacity module takes the computed torques from the inverse model (denoted by Dτ′) as inputs and calculates the muscle forces based on a static optimization criterion (module 410 in FIG. 4). While any cost function can be defined in solving the optimization problem, the one used here minimizes the sum of muscle activations squared
J = ∑ i = 1 m a i 2 ( 10 )
[0056] where m is the number of muscles crossing the joint, a i is the activation level for muscle i and is constrained to be between 0.01 and 1.0. A muscle force F i for muscle i can be represented as below;
F i = a i F i 0 ( 11 )
[0057] where
F i 0
[0058] represents a maximum force limit for muscle i. A gradient based technique can be used to numerically solve for the muscle activations that minimize the cost function J while satisfying the joint moment equilibrium for all degrees of freedom of interest. The optimization problem can be solved using constrained nonlinear optimization (Sequential Quadratic Programming; AEM Design). Once the muscle activations are obtained, the muscle force can then be determined using the force-length-velocity-activation relationship of muscle (Zajac, F. E. Muscle and tendon: Properties, models, scaling, and application to biomechanics and motor control. Critical Reviews in Biomedical Engineering, 17(4):359-41 1, 1989; Anderson, F C and Pandy, M G., Static and Dynamic Optimization Solutions for Gait are practically equivalent, Journal of Biomechanics 34, 2001, 153-161, 2001 ; Hungspreugs, P., Thelen, D., Dariush, B., Ng-Thow-Hing, V., Muscle Force Distribution Estimation Using Static Optimization Techniques. Technical Report-Honda R&D Americas, April 2001).
[0059] The computed muscle forces are then compared with physiological capacity of the muscle in the muscle capacity module 420 . The maximum force limits can be ascertained from the well-studied force-length-velocity relationship of muscle (Zajac 1989, cited above). In addition, the muscle forces with and without the assist torque are compared in order to assess whether the assist torque control has helped (improved efficiency) or hindered the motion. If the assist torque control hinders motion, the muscle forces are adjusted and feasible joint torques are computed (modules 430 and 440 in FIG. 4). A poorly designed assist control would then result in Dτ′≠Dτ, producing a simulated response that would not track the desired response. If the assist torques are well designed, Dτ′=Dτ and the resulting motion would track the desired motion.
[0060] Augmentation Device Controller
[0061] The inputs to the human augmentation device may include the sensed state variables q s and/or {dot over (q)} s , which can be directly measured or estimated. These inputs, denoted by (q s , {dot over (q)} s ) represent a subset of the total number of state variables (q, {dot over (q)}) in our human model. In addition to the sensed state variables, measurements may also be used as input to the augmentation device controller. The augmentation device controller output represents the assist torque τ a , which is then input to the inverse model.
[0062] Different control strategies may be used by the human augmentation device controller. For example, gravity compensation control can be used for tasks requiring an increase in potential energy of the total system (human and exoskeleton). Such tasks would include lifting objects, carrying loads, climbing stairs, rising from a chair, etc. A different control strategy, or hybrid control strategies, may be suitable for other tasks such as walking or running. Here, we will present the gravity compensation control algorithm.
[0063] By using the Lagrangian, we can assess the total potential energy of the musculoskeletal system. Let U denote the total potential energy stored in the system,
U = ∑ i - 1 n m j g T X 1 ( 12 )
[0064] The torque at joint i due to gravity can be computed by taking the partial derivative of U with respect to q i ,
D τ gr = ∂ U ∂ q i = ∑ j = 1 n m j g T ∂ X j ∂ q i ( 13 )
[0065] where g T represents the gravitational acceleration vector, and X j represents the coordinates of the center of mass of segment j. Suppose the knee joint between segment 1 and segment 2 is actuated by an augmentation device and the angle corresponding to q 2 (represents q s ⊂q) is measurable. The following control law may be used as one algorithm for the augmentation device controller
D τ a = D τ g r = ∂ U ∂ q 2 = ∑ j = 1 n m j g T ∂ X j ∂ q 2 ( 4 )
[0066] Note that the above control algorithm requires the center of mass positions of all the link segments (denoted by X j ). Although X j can be derived from measurement of joint angles and segment lengths, it may not be feasible to measure all joint angles and all segment lengths. Alternatively, if the vertical component of the ground reaction force under each foot can be measured or estimated, it is possible to derive an iterative “ground up” gravity compensation algorithm which would eliminate the need for access to center of mass of every segment.
[0067] Integration of Modules
[0068] The block-diagram of the integrated modules as has been presented in the description is shown in FIG. 5. The Augmentation device controller is presumed to have as inputs the sensed states and output the assist torques. The overall framework is very general and enables flexible design of the augmentation device control signals. The details of such designs are easily made by those skilled in the art.
[0069] [0069]FIG. 6 shows a flowchart illustrating a simulation process according to an embodiment of the present invention. At step S 605 , time t is set to 0. At step S 610 , desired kinematic data for the combined musculoskeletal and augmentation device system are obtained. The desired kinematic data may be obtained from motion capture data.
[0070] At step S 612 , the simulated kinematic data is fed back to obtain tracking error.
[0071] At step S 615 , modified accelerations {umlaut over (q)}* are computed using Equation 6.
[0072] At step 617 , the sensed kinematic data is fed back.
[0073] At step S 620 , assist torques Dτ a are computed using the augmentation device controller 500 .
[0074] At step S 625 , torques Dτ′ are computed using Equation 5 (inverse model 300 ).
[0075] At step S 630 , muscle forces are checked and adjusted to modify the corresponding torques (muscle force and capacity module 400 ).
[0076] At step S 635 , the induced accelerations {umlaut over (q)} are computed using Equations 3 and 4 and the simulated kinematic data q and {dot over (q)} are obtained by numerical integration (modules 200 , 210 and 220 ).
[0077] At step S 640 , time t is incremented and at step S 645 , whether t is less than t c or not is determined. If t is less than t c , the process returns to step S 610 . If t is equal to or greater than t c , the process ends.
[0078] It should be noted that the above-mentioned equations, modules or functions can be implemented in any kind of computing devices, including general-purpose computers such as personal computers, work stations and main frame computers, and ASICs (Application Specific Integrated Circuits).
[0079] In an embodiment a general-purpose computer is employed to implement the invention. The general-purpose computer comprises software representing the above-mentioned equations, modules or functions. The software is preferably contained in computer readable mediums. Computer readable mediums include read only memories, random access memories, hard disks, flexible disks, compact disks and so on.
[0080] Simulations
[0081] A very simple simulation of the tracking system is carried out to illustrate some of the concepts proposed in the description.
[0082] A simulation illustrating the tracking characteristics of the proposed method without acceleration estimates of the reference trajectory, is provided. In particular, the double support phase of the biped system during a squatting maneuver was simulated. The results are illustrated in FIGS. 7 to 9 .
[0083] In FIG. 7, the desired and simulated joint trajectories illustrate the effectiveness of the tracking procedure. These results were obtained by setting a=0, i.e. no acceleration estimates were used as inputs to the inverse model. The corresponding joint torques and ground reaction forces are depicted in FIG. 8 and FIG. 9, respectively.
[0084] It should be noted that those skilled in the art can modify or change the above-mentioned embodiments, without departing from the scope and spirit of the present invention. It should therefore be noted that the disclosed embodiments are not intended to limit the scope of the invention, but only to exemplarily illustrate the invention. | A system, a method and a computer readable medium are provided for simulating a combined musculoskeletal and augmentation device system. The dynamics model of the combined musculoskeletal and augmentation device system receives computed torques at the joints as inputs and delivers simulated kinematic data of the segments as outputs. The augmentation device controller for control of the augmentation device, receives the simulated kinematic data as inputs and delivers assist torques as outputs. The inverse dynamics model for the musculoskeletal and augmentation device system, receives the simulated kinematic data, desired kinematic data of the segments and the assit torques as inputs and delivers the computed net joint torque and muscle torque. The muscle force and muscle capacity module for checking and adjusting the computed torques, receives the computed torques as inputs and delivers computed torques as outputs after the checking and adjustment. | 34,265 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of China application serial no. 201110100828.0, filed on Apr. 21, 2011. The entirety of the above-mentioned patent application is hereby incorporated by reference herein and made a part of this specification.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a DC to DC buck converting controller, and more particularly a DC to DC buck converting controller with programmable output voltage.
[0004] 2. Description of Related Art
[0005] FIG. 1 is a schematic diagram of a conventional DC to DC buck converting circuit. The DC to DC buck converting circuit comprises a controller 10 , two switches M 1 and M 2 , an inductance L, a capacitance C, a bootstrap circuit BS and a voltage divider VD. The voltage divider VD detects an output voltage of the buck converting circuit and accordingly generates a feedback signal FB. The controller 10 turns the switches M 1 and M 2 on/off according to the feedback signal FB, so as to make the DC to DC buck converting circuit to convert an input signal Vin into an output voltage Vout which is stabilized at a preset output voltage.
[0006] The controller 10 comprises a comparator 12 , a constant on-time period circuit 14 , a logic control circuit 16 and two gate driving units 18 , 20 . The comparator 12 generates a feedback control signal according to the feedback signal FB and a reference voltage Vref. An on-time period of the constant on-time period circuit 14 is determined by the input voltage Vin and the output voltage Vout, and the constant on-time period circuit 14 generates an constant on-time signal according to the feedback control signal. The logic control circuit 16 determines conduction timing and cut-off timing of the switches M 1 and M 2 , and makes the switches M 1 and M 2 turned on and off separately via the gate driving units 18 and 20 . The switch M 2 is a N-type MOSFET. For avoiding that the gate driving unit 20 in the controller 10 cannot generate a signal which is high enough to turn on the switch M 2 . The bootstrap circuit BS is used supply a sufficiently high voltage to the gate driving unit 20 .
[0007] The constant on-time period circuit 14 adjusts the constant on-time period according to the input voltage Vin and the output voltage Vout to make the DC to DC buck converting circuit operate in a quasi-constant frequency. Therefore, an electromagnetic interference (EMI) generated by the switches M 1 and M 2 can be easily filtered out, regardless of the levels of the input voltage Vin and the output voltage Vout.
[0008] However, the DC to DC buck converting circuit must economize on energy to meet the current energy-saving trend, which means that the DC to DC buck converting circuit needs energy-saving mode to adjust output voltage. Therefore, it is an important issue to support the energy-saving mode on the DC to DC buck converting circuit.
SUMMARY OF THE INVENTION
[0009] The invention uses an extra setting signal to set the level of the output voltage to achieve the function of energy-saving mode for adjusting the output voltage.
[0010] To accomplish the aforementioned and other objects, an exemplary embodiment of the invention provides a DC to DC buck converting controller, adapted to control a DC to DC buck converting circuit which converts an input voltage into an output voltage. The DC to DC buck converting controller comprises a feedback circuit and a driving circuit. The feedback circuit generates a feedback control signal according to a reference voltage and a feedback signal representative of the output voltage. The driving circuit generates at least one control signal to control the DC to DC buck converting circuit according to the feedback control signal. The driving circuit comprises a constant on-time period unit. The constant on-time period unit sets a constant on-time period to make the driving circuit to determine a duty cycle of the DC to DC buck converting circuit according to the level of the reference voltage. Wherein, the level of the reference voltage is determined by a preset output voltage.
[0011] It needs to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed. In order to make the features and the advantages of the invention comprehensible, exemplary embodiments accompanied with figures are described in detail below.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The present invention will now be specified with reference to its preferred embodiment illustrated in the drawings, in which:
[0013] FIG. 1 is a schematic diagram of a conventional DC to DC buck converting circuit;
[0014] FIG. 2 is a schematic diagram of a DC to DC buck converting circuit according to a first embodiment of the invention; and
[0015] FIG. 3 is a schematic diagram of a constant on-time period circuit according to an example shown in the FIG. 2 .
DESCRIPTION OF EMBODIMENTS
[0016] In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawings.
[0017] FIG. 2 is a schematic diagram of a DC to DC buck converting circuit according to a first embodiment of the invention. The DC to DC buck converting circuit comprises a controller 100 , two switches M 1 and M 2 , an inductance L, a capacitance C, a bootstrap circuit BS and a voltage divider VD. The voltage divider VD detects an output voltage Vout of the DC to DC buck converting circuit and accordingly generates a feedback signal FB. The controller 100 turns the switches M 1 and M 2 on/off according to the feedback signal FB, so as to make the DC to DC buck converting circuit convert an input voltage Vin into an output voltage Vout which is stabilized at a preset output voltage.
[0018] The controller 100 comprises a feedback circuit 112 , a driving circuit which comprises a constant on-time period circuit 114 , a logic control circuit 116 and two gate driving units 118 , 120 . The feedback circuit 112 comprises a comparator. An inverting input terminal of the comparator receives the feedback signal FB and a non-inverting input terminal thereof receives a reference voltage Vr and accordingly outputs a feedback control signal Sfb. The constant on-time period circuit 114 receives the feedback control signal Sfb and the reference voltage Vr and accordingly generates a constant on-time signal Sto. A pulse width (time period) of the constant on-time signal Sto is determined by a level of the reference voltage Vr. A starting timing of the constant on-time signal Sto, i.e., rising/falling edge, is determined according to the feedback control signal Sfb. The logic control circuit 116 is coupled with a connection node of the two switches M 1 and M 2 to detect a current of the inductance L and determine turned-on timings and turned-off timings of the two switches M 1 and M 2 according to the feedback control signal Sfb and the current of the inductance L. The logic control circuit 116 turns the two switches M 1 and M 2 on/off via the gate driving units 118 and 120 respectively. In the present embodiment, a duty cycle of the DC to DC buck converting circuit, i.e., a time ratio of a period time to transmit the power from the input voltage Vin into the DC to DC buck converting circuit via the switch M 1 and a cycle time thereof, is determined by turned-on period of the switch M 1 . That is, when a beginning of each cycle (when the level of the feedback signal FB is lower than the level of the reference voltage Vr), the feedback circuit 112 generates a feedback control signal Sfb to make the constant on-time period circuit 114 to generate the constant on-time signal Sto with a constant pulse width (time period). The logic control circuit 116 turns on the switch M 1 according to the constant on-time signal Sto. After the constant pulse width (time period), the logic control circuit 116 turns the switch M 1 off and turns the switch M 2 on to make the current of the inductance L freewheel through the switch M 2 . When the current of the inductance L is decreased to zero, the switch M 2 is turned off.
[0019] The reference voltage Vr may be an external control signal, which a level of the reference voltage Vr is determined by an external circuit or set by users according to a preset output voltage. In the present embodiment, the controller 100 further comprises a reference voltage generating circuit 115 . The reference voltage generating circuit 115 generates a reference base voltage Vr 0 . The user makes the reference base voltage Vr 0 divided into a demand reference voltage Vr by a voltage divider and transmits the reference voltage Vr into the feedback circuit 112 and the constant on-time period circuit 114 . The voltage divider comprises the resistances RV 1 , RV 2 and a voltage division ratio thereof is set by the input voltage Vin and the preset output voltage. In addition, the voltage division ratio of the voltage divider VD may affect the ratio of the feedback signal FB and the output voltage Vout. Therefore, the ratio of the resistances RV 1 , RV 2 is set according to the voltage division ratio of the voltage divider VD.
[0020] FIG. 3 is a schematic diagram of a constant on-time period circuit according to a second embodiment of the invention. The constant on-time period circuit 114 comprises a current source I, a period capacitance Cton and a comparator 1141 . The current of the current source I is set by a current mirror MI and an on-time period resistance Rton. The on-time period resistance Rton is coupled with the input voltage
[0021] Vin and so a current flowing through the on-time period resistance depends on the the input voltage Vin. The current flowing through the on-time period resistance is mirrored to the current source I by the current mirror MI. On the beginning of each cycle, the period capacitance Cton is charging from zero by the current source I. The comparator 1141 compares the voltage of the period capacitance Cton with one of the original voltage Vset and the reference voltage Vr to generate the constant on-time signal Sto, and the original voltage Vset is higher than the reference voltage Vr. On the beginning of enabling the circuit, the comparator 1141 compares the voltage of the period capacitance Cton with the original voltage Vset to make the on-time period longer and so the output voltage Vout could be increased faster. Just before or when the output voltage Vout reaches the preset voltage, the comparator 1141 compares the voltage of the period capacitance Cton with the reference voltage Vr to make the output voltage Vout to be stabilized on the preset output voltage. The constant on-time period circuit 114 further comprises a SR flip-flop 1142 and an inverter 1143 . A set terminal S of the SR flip-flop 1142 is coupled with the output terminal of the comparator 1141 through the inverter 1143 , a reset terminal R thereof is coupled with the feedback circuit 112 and an output terminal is coupled with the discharging unit SWd. The discharging unit SWd is coupled with two ends of the period capacitance Cton to discharge the period capacitance Cton according to the controlling of the SR flip-flop 1142 . When the voltage of the period capacitance Cton is higher than the reference voltage Vr, the constant on-time signal Sto is changed into low level to trigger the SR flip-flop 1142 through the inverter 1143 . Then, the discharging unit SWd discharges the period capacitance Cton. When the output voltage Vout is lower than the preset voltage, the feedback control signal Sfb is at high level to make the SR flip-flop 1142 reset to stop the discharging unit SWD discharging. Therefore, on the beginning of each cycle, the output voltage Vout is lower than the preset output voltage and the period capacitance Cton is charged by the current sources I. When the voltage of period capacitance C is higher than the reference voltage Vr, the period capacitance Cton is discharged to zero voltage to wait for the next cycle.
[0022] All the features disclosed in this specification (including any accompanying claims, abstract, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features. | A constant on-time period of a DC to DC buck converting controller is adjusted according to a level of a preset output voltage. Therefore, the DC to DC buck converting controller of the present invention is suitable for any applications with different requests of output voltages or different operating mode. | 13,306 |
FIELD OF INVENTION
[0001] The present invention relates to pharmaceutical formulations for topical application and manufacturing processes therefor, which are suitable for the treatment of various topical infections.
BACKGROUND OF THE INVENTION
[0002] Anaerobic bacteria are frequently found in infections of the skin, soft tissue, bones and in bacteremia. Injury to skin, bone or soft tissue by trauma, ischemia or surgery creates a suitable environment for anaerobic infections. Since the sites that are colonized by anaerobic bacteria contain many species of bacteria, disruption of anatomic barriers allows penetration of many organisms, resulting in mixed infections involving multiple species of anaerobes combined with facultative or microaerophilic organisms.
[0003] Two-thirds of clinically significant anaerobic infections involve following five anaerobes: Bacteroides fragilis group, Bacteroides melaninogenicus groups, Fusobacterium nucleatum, Clostridium perfringens , and anaerobic cocci.
[0004] Certain types of infections as stated below in Table 1 commonly involve anaerobic bacteria including lower extremity infections in diabetics or in patients with severe peripheral vascular disease.
TABLE 1 Skin and soft Incidence of anaerobic tissue infections involvement (%) Diabetic foot ulcers 95 Infected diabetic gangrene 85 Non-clostridial crepitant cellulitis 75 Decubitus ulcer with bacteremia 63 Cutaneous abscesses 62 Soft tissue abscesses 60 Topical infection of head and neck 48 Topical infection of trunk 36 Topical infection of hand 31 Topical infection of buttock 33
[0005] Therefore, there are many conditions such as diabetic ulcers, decubitus ulcers, cellulitis, pyoderma etc. that have aerobic and anaerobic microflora. Thus, it is rational to use an agent having action on both types of organisms.
[0006] U.S. Pat. No. 4,803,066 describes antibacterial and antifungal composition for topical application the composition comprise azole derivative with silver compound. Metronidazole 1% solution is reported to be effective in treating various ulcers which included pressure sores in elderly and chronically ill patients, diabetic ulcers, venous ulcers. The solution was also used as irrigation or packs in the management of ischiorectal abscess, large abscesses in other areas, undermining subcutaneous cavitation complicating simple sacral pressure sores. Metronidazole topical therapy is also recommended for anaerobic decubitus ulcers (Grade III & IV), marginal cellulitis and sacral ulcers.
[0007] U.S. Pat. No. 5,407,670 describes topical ointment for the treatment of epidermal trauma such as burns, rashes, lesions, wounds and decubital ulcers, which contains povidone-iodine along with polymyxin, bacitracin, neomycin, and sugar. U.S. Pat. No. 5,137,718 describes infection fighting composition for topical application containing povidone-iodine complex for viricidal or microbial agent.
[0008] Patients admitted in ICU, trauma ward, emergency wards, burn wards, unconscious patients, patients with neurological/spinal disorders and patients undergoing urinary tract surgery are often catheterized. Bladder irrigation with Povidone-Iodine is effective in prevention of urinary tract infection after single or intermittent catheterization.[Van Den Broek P J, Lancet, March, 1(8428), 5635, 1985].
[0009] Metronidazole is a bactericidal. It has activity against the facultative anaerobes Gardnerella vaginalis and Helicobacter pyroli and is effective against some spirochetes. Moreover, several protozoa and anaerobic bacteria including Bacteroides and Clostridium Spp. are sensitive to Metronidazole. Efficacy of metronidazole against obligate anaerobic bacteria in vitro including the gram-negative organisms Bacteroides fragilis , Fusobacterium Spp., Peptococcus Spp., Peptostreptococcus Spp., and Villanelle Spp. is well established.
[0010] The mechanism of action of Metronidazole is thought to involve interference with DNA by a metabolite in which a nitro group of metronidazole has been reduced by bacterial nitroreductases to an unstable intermediate, which interacts with DNA, effectively preventing further replication.
[0011] A Variety of nitroimidazoles are widely used as anti bacterial, antitrichomonal, anti-parasitic agents. Representative active agents are tinidazole, nimorazole, panidazole, flunidazole, ronidazole but metronidazole is the only one which is widely accepted in therapy.
[0012] Metronidazole is considered the ‘gold standard’ against which other antimicrobials with perceived anti-anaerobic activity are compared. This is due primarily to its killing of Baceroides spp., and the very low rate of resistance acquired by these bacteria.(Olsson-Liljequist B, Nord C E, Scand. J. Infect. Dis., 1981: Suppl. 26: 24-5, Aldridge K E, Gelfand M, Relier L B, et al; Aldridge K E, Gelfand M, Relier L B, et al; Diagn. Microbiol. Infect. Dis.; 1994; 18:235-41; Selkon J B, Scand. J. Infect. Dis., 1981: Suppl. 26: 19-23; Sigeti J S, Guiney Jr D G, Davis C E, J. Infect. Dis., 1983; 148:1083-9; Scher K. S., Surg. Gyn. Obstet., 1988: 167:175-9)
[0013] The cure rates in patients with intra abdominal infections such as Gangrenous or perforated appendicitis improvement occurred in 100% of the patients. (Willis A. T., Ferguson I. R., et al., B. Med. J., 1976: 1: 318-21; Foster M. C., Kaplia L et al., Rev. Infect. Dis., 1986: 8 Suppl.5: 5634-8.)
[0014] Metronidazole is much more in therapeutic use compared to other nitormidazoles. Metronidazole was marketed for therapeutic use in February 1960.
[0015] Metronidazole is the only nitroimidazole available for topical treatment. Metronidazole 0.8% gel is used for treatment of malodeorous fungating tumors, Decebitus ulcers and varicose ulcers. Metronidazole 0.75% cream is employed for treatment of rosacea.
[0016] Iodine has long been accepted as a uniquely effective antiseptic and used widely both for the prevention and treatment of infection. It has a broad antimicrobial spectrum: bacteria, viruses, bacterial endospores, fungi, and protozoas are destroyed, however, been limited by a number of undesirable factors. The disadvantages of iodine are an unpleasant odor and staining properties, unstability and irritation potential of solutions to animal tissue. Iodine solutions may prove toxic to open wounds.
[0017] An iodophor which is a complex of iodine in ionic or molecular form or both with a carrier that serves to increase the solubility of iodine in water and also provides a reservoir of iodine for a controlled and sustained release over time. There are two categories of iodophors, water-soluble and water insoluble. An example of a water-soluble iodophor is the polyvinylpyrrolidone-iodine complex widely used as a germicidal solution. An example of a water insoluble iodophor is polyvinyl alcohol sponge complexed with iodine, which can be used to wipe down and disinfect hard surfaces.
[0018] It was discovered that Povidone-Iodine [iodine complexed with the inert polymer, polyvinylpyrrolidone (povidone)] ceases to irritate, sensitize or stain and yet retains its unique microbicidal activity as iodine is continually delivered. Biochemical research has indicated that this high degree of microbiocidal activity is the result of the interruption of vital metabolic pathways. This is accomplished by the iodination of the amino acid sequence of the microorganisms' proteins. [Bloomfield S. F., “Chlorine & Iodine Formulations”, in Handbook of Disinfectants & Antiseptics, Ed. By Ascezi J. M., Marcel Dekker Inc., NY, 1996, pp 147-149]
[0019] Povidone-Iodine is effective against variety of strains such as Staphylococcus aureus, Proteus mirabilus, Proteus vulgaris, Escherichia coli, Enterobacter areogenes , Enterobacter Spp., Streptococcus faecalis, Streptococcus pyogenes, Streptococcus hemolyticus, Salmonella typhimurium, Salmonella typhosa , Salmonella type C1, Salmonella Spp., Serratia marcescens , Serratia Spp., Shigella sonni, Pseudomonas aeruginosa, Klebsiella pneumoniae, Diplococcus pneumoniae, Mycobacterium tuberculosis, Bacillus subtillis, Clostridium septicum, Clostridium tetani, Bacillus subtillis spores, Trichophyton rubrum, Candida albicans, richomonas vaginalis, Aspergillus flavus, Aspergillus niger.
[0020] Povidone-iodine is used for the treatment of burns and of different skin lesions (decubitus and leg ulcers, etc.). In special preparations it is available for the therapy of inflammations in the mouth and pharynx and for vaginitis. Povidone-Iodine is used in the treatment of skin disinfection in the prevention of nosocomial infections, especially, prior to invasive procedures such as the insertion of peripheral catheters, treatment of exit site infection [Tanaka S., Advances in Peritoneal Dialysis, 12, 214-7, 1996] and bacteraemia in haemodyletic patients [Fong I. W., Postgraduate Medicinal Journal, 69, Suppl 3S15-7, 1993]. It is also used as surgical scrub as an effective method for avoiding intra as well as post-surgical infection. [Tucci V. J., Stone A. M., Thompson C., Isenberg H. D., Wise L, Surg. Gynecol. Obstet., 145(3), 415-6,1977] Povidone-iodine cream effectively limits bacterial infection in patients with traumatic lacerations requiring sutures. [Gravett et al, Annals of Emergency Medicine, 16(2), 167-71, 1987].
[0021] Water soluble iodophors forms micellar aggregates which enables a reduction in the concentration of free available iodine in water as well as simultaneous reduction in the disadvantages of iodine i.e. its unpleasant odor, irritation and staining of tissue, and corrosion of metal surfaces. An important factor in creating an iodophor is that one wishes to keep the concentration of free iodine in the solution as low as possible; to be effective
SUMMARY OF THE INVENTION
[0022] Thus, taking into consideration the limitations associated with the conventional topical composition with individual active agents stated above, the present inventor has discovered a composition comprising of an iodophor and a alkyl imidazole, which has a wide antimicrobial activity against aerobic as well as anaerobic bacteria. Preferably, the composition comprises metronidazole and povidone-iodine. Povidone-Iodine acts against aerobic organisms and metronidazole acts against anaerobic organisms.
[0023] The present invention provides formulations and methods for the treatment of individuals affected with various skin infections and injuries, such as pre-operative and post-operative antisepsis, diabetic ulcers, lapromatous ulcers, decubitus ulcers, cellulitis, and other skin infection showing the presence of both aerobic and anaerobic microorganisms, as well as wounds, such as contaminated lacerations, accidental wounds, traumatic wounds, abrasions, thermal wounds (Burns of 1st, 2nd, 3rd degree), and animal and human bites. The present invention also provides formulations and methods for the treatment of mycotic infections such as pyoderma, otitis externa, tinea pedis, tinea cruris, tinea corporis, tinea versicolor, and cutaneous candidiasis, topical treatment of monialliasis, trichomoniasis, and non-specific vaginitis. Moreover, the present invention provides formulations and methods for prophylactic treatment of patients, such as bladder irrigation during catheterisation and before catheter removal, and as a disinfectant in small surgical procedures, and in catheter (peritoneal/dialysis) exit site wounds.
[0024] None of the references mentioned earlier in the text teach the combination of metronidazole and povidone-iodine for treatment of microbial and mycotic infections caused by aerobic as well as anaerobic microorganisms. It is a object of this invention to provide a pharmaceutical formulation comprising combination of metronidazole and Povidone-Iodine in the form of topical pharmaceutical composition having the effect on aerobic and anaerobic bacteria. This combination has been found to be therapeutically advanced over either metronidazole or Povidone-Iodine individually with improved patient compliance.
[0025] The combination offers following advantages:
[0026] Easy application schedule i.e. single application takes care of both the types i.e. aerobic and anaerobic organisms.
[0027] Reduced number of applications.
[0028] Broad spectrum of anti microbial activity
[0029] Rapid control of infection.
[0030] This formulation when applied on the affected part, flows and fills out the wounded area after application and thereafter comes into contact with the damaged tissue with microbial infection. Metronidazole exerts its aerobicidal activity and Povidone-Iodine reacts with amino acids of microbial cell wall of anaerobic bacteria present thereby killing the microbes. Thus, the combination comprising Metronidazole and Povidone-Iodine is therapeutically better over either metronidazole or Povidone-Iodine individually. The combination has a topical microbicidal activity against bacteria including spores, fungi, yeast, protozoa and viruses, even in presence of blood, serum, pus and necrotic tissue.
DETAILED DESCRIPTION OF THE INVENTION
[0031] The present invention is a pharmaceutical composition for topical application comprising of an iodophor and a alkyl imidazole, which has a wide antimicrobial activity against aerobic as well as anaerobic bacteria. Preferably, the composition comprises metronidazole and povidone-iodine. Povidone-Iodine acts against aerobic organisms and metronidazole acts against anaerobic organisms.
[0032] The term “pharmaceutical composition for topical application”, as used herein, means various compatible dosage forms which are suitable for administration to a human or veterinary application.
[0033] Suitably, the compositions is adapted for topical administration which include for instance, ointments, solutions, creams or lotions, powder, topical patches, aerosols and can be used in the form of scrub, irrigating solution and paint. In addition, compositions of the present invention may be used in impregnated dressings. Compositions of the present invention may also contain appropriate conventional additives such as preservatives, chelating agents, solvents to assist drug penetration and emollients, hydrocarbon waxes, oleaginous substances, fatty acids and fatty alcohol in ointments and creams. Ingredients present in the topical carrier of the present invention are suitable for administration to different infected sites.
[0034] Such a preparation is most preferably administered in the form of ointment and solution although the other dosage forms are also advantageously envisioned. Advantages to administering the composition as a ointment and solution include convenience, ease of application, increased safety.
[0035] Preferred pharmaceutical compositions for topical application according to the present invention comprises of metronidazole or a pharmaceutically acceptable salt or ester thereof from 0.01 to 10%, preferably from 0.05 to 5% and most preferably 1% by weight of the composition.
[0036] Metronidazole, i.e., 1-(beta-hydroxyethyl)-2-methyl-5-nitroimidazole, belongs to the class of alkyl imidazole derivatives and are useful as antimicrobial agents. The term “metronidazole,” as used in this specification and claims, includes not only 1-(2-hydroxyethyl)-2-methyl-5-nitroimidazole, but also those analogs and derivatives of metronidazole (salts, esters etc) that are soluble in the pharmaceutical compositions described herein and which exhibit therapeutic activity when applied as taught by the present invention.
[0037] A preferred pharmaceutical compositions for topical application according to the present invention comprises of Povidone-Iodine from 1 to 20%, preferably from 3 to 10% and most preferably 5% by weight of the composition.
[0038] Specific examples of iodophors useful in this invention include polyvinylpyrrolidone-iodine, polyvinyl alcohol-iodine, polyvinyl oxazolidone-iodine, polyvinyl imidazole-iodine, polyvinyl morpholone-iodine, polyvinyl caprolactam-iodine, soluble starch-iodine, betacyclodextrin-iodine, polyoxyethylenepolyoxypropylene condensate-iodine, and ethoxylated linear alcohol-iodine, with polyvinyl pyrrolidone-iodine being the most preferred. The iodophor as mentioned in the present invention is characterized by enhanced bactericidal, germicidal and other biocidal activity, and reduced vapor pressure and odor. Staining is virtually non-existent and wide dilution with water is possible.
[0039] The preferred pharmaceutical composition of the present invention is in the form of ointment comprising metronidazole and povidone-iodine impregnated in a suitable water soluble base. The means of formulating water soluble ointment bases are known to those skilled in the art. A water soluble base lowers surface tension of the composition aiding uniform distribution of the composition.
[0040] Water soluble bases are prepared from mixtures of high and low molecular weight polythylene glycols, which have general formula HOCH 2 [CH 2 OCH 2 ] n CH 2 OH. Suitable derivatives include ethers and esters of the poly (substituted or unsubstituted alkylene) glycols, such as macrogol ethers and esters e.g. cetomacrogol; glycofurol; block copolymers including poly (substituted or unsubstituted alkylene) glycols such as block copolymers of polyethylene glycol and polypropylene glycol and cross-linked polyethylene glycols.
[0041] Various grades of poly (substituted or unsubstituted alkylene) glycols and derivatives thereof may be used in combination to achieve the desired physical properties of the formulation. Preferably the formulation comprises polyethylene glycol or a derivative thereof which are commercially available in a variety of chain lengths and with a variety of consistencies. Suitable polyethylene glycols include PEG 300 and PEG 400 (liquids); PEG 1000 (semi-solids); and PEG 4000 and PEG 6000 (hard solids).
[0042] These may be used singly or admixed in suitable proportions to achieve the desired consistency of formulation. A preferred combination comprises PEG 4000 and PEG 400, suitably in a ratio of from 0.5:1 to 1:5, preferably from 1:1 to 1:3; most preferably about 1:2.
[0043] Typically, the vehicle comprises at least 70%, preferably at least 80%, most preferably at least 90% by weight of a pharmaceutically acceptable poly (substituted or unsubstituted alkylene) glycol or a derivative thereof.
[0044] Where the pharmaceutical composition is in the form of solution the active ingredients are combined with following ingredients:
[0045] Surface active agent
[0046] Co-solvent
[0047] Buffering agent
[0048] The expression “Surface active agent” as used in this specification refers to anionic surfactant. Such a sufactant provides better surface contact of the composition with infected area.
[0049] Specific preferred anionic surfactants include, but are not limited to, lauryl sulfates, octyl sulfates, 2-ethylhexyl sulfates, decyl sulfates, tridecyl sulfates, cocoates, lauroyl sarcosinates, lauryl sulfosuccinates, diphenyl oxide disulfonates, lauryl sulfosuccinates, myristyl sulfates, oleates, stearates, tallates, ricinoleates, cetyl sulfates, and similar surfactants.
[0050] However, sodium lauryl sulphate is preferably used as a surface active agent in the solution composition of the present invention in an amount of 0.1% to about 5.0% by wt. and preferably, in an amount of about 0.5% by wt. based on the total wt. of the composition.
[0051] The expression “co-solvent” as used in this specification refers to used in combination to increase the solubility of the solutes. Examples of preferred class are ethanol, sorbitol, glycerin, propylene glycol and members of polyethylene glycol polymer series. However, Polyethylene glycol 400 is preferably used as a cosolvent in the solution composition of the present invention in an amount of 2.5% to about 10.0% by wt. and preferably, in an amount of about 5.0% by wt. based on the total wt. of the composition.
[0052] The expression buffering agent as used in this specification refers to combination of basic pH adjuster and acidic pH adjuster.
[0053] Examples of preferred classes of basic pH adjusters are ammonia; mono-, di- , and tri-alkyl amines; mono-, di-, and tri-alkanolamines; alkali metal and alkaline earth metal hydroxides; alkaline phosphates and mixtures thereof. However, the identity of the basic pH adjuster is not limited, and any basic pH adjuster known in the art can be used. However, Dibasic sodium phosphate is preferably used as basic pH adjuster in the solution composition of the present invention in an amount of 2.5% to about 5.0% by wt. and preferably, in an amount of about 3.83% by wt. based on the total wt. of the composition.
[0054] The preferred classes of acidic pH adjusters are the mineral acids and polycarboxylic acids. Examples of mineral acids are hydrochloric acid, nitric acid, phosphoric acid, and sulfuric acid. Nonlimiting examples of polycarboxylic acids are citric acid, glycolic acid, and lactic acid. The identity of the acidic pH adjuster is not limited and any acidic pH adjuster known in the art, alone or in combination can be used. However, Citric acid is preferably used as acidic pH adjuster in the solution composition of the present invention in an amount of 0.5% to about 2.0% by wt. and preferably, in an amount of about 1.63% by wt. based on the total wt. of the composition.
[0055] The most preferred composition has a pH of below 7, most preferably between 5 to 6.5.
[0056] The pharmaceutical composition of the invention in the form of ointment can be prepared as follows: Metronidazole is dissolved in a mixture of PEG 400 and water under stirring. Then Povidone-Iodine is added to above solution and dissolved under stirring. Then PEG 4000 is melted by heating to 60-65° C. and then added to the above viscous solution under stirring. The mixture is allowed to cool to room temperature to form uniform viscous ointment.
[0057] The pharmaceutical composition of the invention in the form solution can be prepared by the method stated below:
[0058] The buffer is prepared by dissolving dibasic sodium phosphate and citric acid in water. Povidone-Iodine is dissolved in buffer under stirring. Metronidazole is dissolved in PEG 400 under stirring and added to the above solution containing Povidone-Iodine with mixing. Sodium lauryl sulphate is dissolved in water and added to the bulk solution under stirring. The volume is adjusted with water to get the specified concentration.
[0059] To investigate the effectiveness of the present invention in various types of wounds, controlled clinical trials were carried out all over India.
[0060] This study is not disclosed to the public and the trials are done in confidence. The results of clinical study in India are given below.
[0061] 40 patients having lacerated wound were included in the study to evaluate the efficacy and safety of Metronidazole and Povidone-Iodine ointment as described in present invention and its comparison with Povidone-Iodine ointment 5%. Patients were divided in to two groups of twenty each. Group one received treatment with Povidone-Iodine ointment 5% where as group two received treatment with Metronidazole and Povidone-Iodine ointment as described in present invention. General and wound parameters such as pain, tenderness, edema, discharge, stages of healing, final healing, type and strength of scar were recorded. Treatment was given twice a day in each group. In group one healing took place in 8 weeks where as in group 2 it took 5 weeks. The improvement in pain, tenderness, edema and discharge improved much faster in Metronidazole and Povidone-Iodine ointment group as described in present invention group compared to Povidone-Iodine 5% group. Similarly scar formation was much faster in Metronidazole and Povidone-Iodine ointment as described in present invention group than Povidone-Iodine 5% ointment.
[0062] 50 patients suffering from Bacterial and mycotic skin infections were included in the trial. They were divided in to two groups 25 each. Group 1 received treatment with Povidone-Iodine ointment 5% and group 2 received Metronidazole and Povidone-Iodine ointment as described in present invention ointment. Both the ointments applied twice a day. The time for recovery, signs of inflammation and response of the lesions were monitors. All patients completed study without any side effect. The healing of lesions in Povidone-Iodine ointment 5% group occurred in 9 days while in Metronidazole and Povidone-Iodine ointment as described in present invention ointment group healing occurred in 6 days. Inflammatory parameters showed faster remission in Metronidazole and Povidone-Iodine ointment as described in present invention group than Povidone-Iodine ointment 5% group.
[0063] 50 patients undergoing gastrointestinal surgery were included in the evaluation of Metronidazole and Povidone-Iodine solution as described in present invention 5% solution and its comparison with Povidone-Iodine 5% solution as pre operative and post-operative anti-sepsis. They were divided two groups of 25 each group 1 received treatment with Povidone-Iodine 5% solution as pre and post operative scrub and Povidone-Iodine 5% ointment post operatively applied twice a day on operation wound. Group 2 received Metronidazole and Povidone-Iodine solution as described in present invention 5% solution as pre and post-operative scrub and Metronidazole and Povidone-Iodine solution as described in present invention 5% ointment as application twice a day on surgical wound. There were no serious post operative wound infections in any of the group. However, healing of the wound was much faster in Metronidazole and Povidone-Iodine solution as described in present invention group than Povidone-Iodine 5% solution group.
[0064] 30 patients undergoing gastrointestinal surgery were included in the evaluation of Metronidazole 1% gel and Metronidazole and Povidone Iodine ointment. 30 patients were divided in to group of 15 each Group I received Metronidazole 1% Gel in form of topical application over incision post-operatively and Group II received Metronidazole and Povidone Iodine ointment applied topically on incision post-operatively. The dressing in both the group done daily and ointment and gel were applied twice daily. There were no serious post-operative wound infection in any of the group however healing of the wound was faster in Metronidazole and Povidone Iodine ointment group compared to Metronidazole 1% gel group.
[0065] Above clinical studies confirm the efficacy of the present pharmaceutical composition of this invention:
[0066] From this trial it can be concluded that Metronidazole and Povidone-Iodine as described in present invention is better than Povidone-Iodine alone in the management of bacterial and mycotic skin infections. This can be attributed to the unique combination comprising Metronidazole, an anaerobicidal agent and Povidone-Iodine, an aerobicidal agent which offered significantly rapid reduction due to the synergistic effect. This can be attributed to the unique combination comprising metronidazole, an anaerobicidal agent, and povidone-iodine, an aerobicidal agent, that offers significant rapid reduction of infection due to their combined action, which increases the effectiveness of each other.
[0067] The invention will now be illustrated by the following Examples:
EXAMPLE 1
[0068] [0068] Metronidazole 1.00% Povidone-Iodine 5.00% Polyethylene glycol 4000 30.00% Polyethylene glycol 400 59.75% Purified Water 4.25%
[0069] The ointment preparations of the invention can be prepared by dissolving Metronidazole in a mixture of PEG 400 and water under stirring. Then adding Povidone-Iodine to above solution and dissolving under stirring. Then melting PEG 4000 by heating to 60-65° C. and adding to the above viscous solution under stirring. Allowing to cool to room temperature to form uniform viscous ointment.
Metronidazole 2.00% Povidone-Iodine 10.00% Polyethylene glycol 4000 30.00% Polyethylene glycol 400 59.75% Purified Water 4.25%
[0070] The same procedure as used in Example 1 was repeated only change is the concentration of the metronidazole and Povidone-Iodine are different to that of Example 1.
Metronidazole 1.00% Povidone-Iodine 5.00% Polyethylene glycol 400 5.00% Sodium lauryl sulphate 0.50% Dibasic Sodium phosphate 3.83% Citric acid 1.63% Purified Water 4.25%
[0071] The solution preparation of this invention can be prepared by dissolving dibasic sodium phosphate and citric acid in water. In this solution dissolving Povidone-Iodine under stirring. Then dissolving metronidazole in PEG 400 under stirring and adding this solution to the above solution containing Povidone-Iodine. Mixing well. Then dissolving sodium lauryl sulphate in water and adding this to the bulk solution under stirring. Mixing well and adjusting the volume with water to get the specified concentration.
Metronidazole 2.00% Povidone-Iodine 10.00% Polyethylene glycol 400 5.00% Sodium lauryl sulphate 0.50% Dibasic Sodium phosphate 3.83% Citric acid 1.63% Purified Water 4.25%
[0072] The same procedure as used in example 3 was repeated only change is the concentration of the metronidazole and Povidone-Iodine are different to that of example 3.
[0073] In addition the combination of Metronidazole and Povidone-Iodine may be applied or formulated contemporaneously with other topical agents to provide synergistic or amplified activity for management of wounds.
[0074] It is to be understood that the example and embodiments described hereinabove are for the purpose of providing a description of the present invention by way of example and are not to be viewed as limiting the present invention in any way. Various modifications or changes that may be made to that described hereinabove by those of ordinary skill in the art are also contemplated by the present invention and are to be included within the spirit and purview of this application and the stated claims. | A pharmaceutical composition for topical application and manufacturing process thereof for treatment of microbial and mycotic infections caused by aerobic and anaerobic microorganisms is provided comprising metronidazole and Povidone-Iodine, in effective amounts. Such a composition can be administered topically to patients in need thereof in various pharmaceutical dosage forms. | 32,061 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The subject invention relates generally to sharpeners for writing or drawing implements and, more specifically, to electric sharpeners for crayons.
2. The Prior Art
Crayon or pencil sharpeners are common consumer products. Typically such devices are designed to be either portable or mounted to a surface in a fixed fashion. The configuration of conventional sharpeners provide a conical block with opposed walls defining an implement receiving channel. The walls provide sharpening edges, of either metallic or plastic composition, that extend from the base of the housing to its apex. The edges engage and shave the surface of the crayon or pencil as the implement is pressed into the opening and rotated.
In regard specifically to crayon sharpeners, the crayon is inserted downward into the conical housing and rotated against the wall edges. The tip of the crayon, formed of wax, plastic, or similar material, is shaved layer by layer into a conical form, tapering to a point. The shavings pass through openings between the wall edges into a receptacle below that can be detached and emptied when full. Electric sharpeners are designed to rotate the cutting block while the user holds the writing implement stationary against the cutting edges.
Representative of known sharpeners are the embodiments set forth in U.S. Pat. Nos. 2,857,881; 4,248,283; and 4,991,299. The cutting elements in each are of the type described above. The '881 embodiment is of note for showing a crayon carton that provides a sharpening element in one of the carton sidewalls. The shavings are collected within a separate internal compartment of the carton and emptied by opening one of the carton flaps.
The state of the art sharpeners work well and are widely accepted by their users. However, several shortcomings are attendant their use, particularly in the sharpening of crayons. In order to appreciate the shortcomings it is important to note that crayons are coloring implements formed by a molding operation into a specific point configuration of plastic or wax, to provide a coloring tip of optimal utility. The form of the tip is frustroconical, tapering downward from a inwardly stepped annular shoulder to a flat circular nose. The flat nose, wider than a point, is more suitable for coloring than a point for it enables a wider band of color to be applied with each stroke. A paper or plastic sleeve is formed to encase the crayon and is either removed by hand prior to sharpening the point or removed by the sharpener during the sharpening procedure.
The molded form of the tip created in the manufacture of the crayon is optimal for its intended use, but quickly deteriorates with use. The post manufacture sharpening of the crayon into a sharp point, as done with prior art sharpeners, however, creates a crayon tip that is inferior to that formed in the original mold. A sharp point will wear down quickly into all undesirable dull round shape. Moreover, a sharp point is much more inefficient in laying) a wide band of color with each stroke.
In addition, the paper jacket surrounding the crayon is relatively abrasive to cut when compared to the soft crayon material. Repeated use of known sharpeners against such a jacket can cause plastic cutting blades of conventional sharpeners to dull quickly. Removing the sleeve by hand can eliminate this deficiency but is inconvenient from the user's standpoint.
Another deficiency in available sharpeners, particularly electrically driven versions, is that they lack adequate user safeguards. Since the users of crayon sharpeners are young children, it is important to guard the user from contact with the cutting blades of the sharpener, both during the sharpening procedure and when the shavings receptacle is being emptied. Moreover, safeguards are needed to insure that young users will not damage the crayon sharpener by inserting into the cutting station inappropriate objects that are much harder than crayons, such as pencils or pens. Commercial sharpeners have blades that are relatively difficult to maintain or repair. Lastly, young users are more likely to use sharpeners in such a manner as to cause end portions of the crayon to break off in the cutting station. Available sharpeners neither deter such breakage nor facilitate easy removal of the broken pieces from the cutting station.
SUMMARY OF THE INVENTION
The subject invention overcomes the aforementioned shortcomings by providing a crayon sharpener that restores the crayon tip to its manufactured configuration, facilitates safe and convenient repair and maintenance but reduces the need therefor; and contains safety features that protect young users. In addition, the sharpener incorporates a built-in piece ejection pin for expelling broken crayon tips from the cutting station.
The subject sharpener comprises a carry case having an internal storage compartment or storing crayons and other supplies, and a battery driven crayon sharpener built into one of he carry case sidewalls. The sharpener comprises a fixedly mounted battery and drive tear rain and a removable cartridge module. The cartridge module couples to the drive gear train in use and includes a cartridge block having four independently oriented cutting blades and a shaving collecting drawer therebeneath.
The cartridge block has an axial bore therethrough dimensioned to receive a crayon and a pair of conically beveled plastic blades at an inward end of the bore positioned to contact a forward end of the inserted crayon. The motor drive train rotates the cartridge block, causing the plastic blades to impart a conical nose to the forward crayon end and to cut an instepped annular shoulder around the conically formed crayon tip.
A preparatory steel blade is also provided, mounted to the cartridge block and oriented normal to the crayon axis and positioned to contact a forward peripheral surface of the canyon and score the jacket therearound. A secondary steel blade is mounted to the cartridge block and oriented parallel to the axis of the crayon. The secondary blade rotates with the block to peel off and remove the paper covering that was scored by the preparatory steel blade mounted normal to the crayon axis.
An ejector pin is positioned to extend coaxially with the forward end of the cartridge block bore and provides a vertical forward surface that operates to form a flat vertical nose surface on the crayon tip during the sharpening procedure. Combined, the action of the blades and ejector pin forward surface restore the crayon tip to its original manufactured configuration. In addition, the ejector pin is spring loaded by insertion of the crayon into the cartridge block. Upon removal of the crayon the forward surface of the ejector pin moves into the cartridge block bore to dislodge any broken crayon pieces therein which thereupon fall down into the module drawer.
Automatic motor engagement and disengagement responsive to insertion of the crayon is provided and the gear train driving the cartridge block is configured to disengage the drive whenever an article harder than a crayon such as a pencil or pen, is inserted into the cartridge bore. The motor also is disabled whenever the cartridge module is removed from the carry case sidewall. The cartridge module shaving drawer can be readily emptied through a side door and an internal flange within the drawer prevents the user from placing fingers in proximity to the cartridge block blades above the drawer. The blades, however, can be accessed if necessary when the cartridge module is disattached for repair or replacement of the blades.
Accordingly it is an objective of the subject invention to provide a crayon sharpener that restores the forward tip of a worn crayon to its original configuration.
A further objective is to provide a sharpener that self-ejects broken crayon pieces from the cutting station.
Another objective is to provide a crayon sharpener that provides ready access to cutting blades for maintenance or replacement.
An objective of the invention is to provide a crayon sharpener having automatic drive motor engagement and disengagement responsive to the presence of a crayon.
An objective of the invention is to provide a crayon sharpener that automatically disables the drive motor when a harder implement such as a pen or pencil is inserted into the cutting station.
Yet a further objective is to provide a crayon sharpener having cutting blades of respective material composition.
A further objective is to provide a crayon sharpener having a removable module for blade access and for shavings disposal.
Still a further objective is to provide a crayon sharpener that is made of relatively few parts and that requires a low level of maintenance.
Another objective is to provide a crayon sharpener that is economically and readily produced, readily assembled and that is convenient to the user.
These and other objectives, which will be apparent to those skilled in the art, are achieved by a preferred embodiment that is described in detail below and illustrated in the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the assembled sharpener.
FIG. 2 is an exploded perspective view of the carry case and motor housing.
FIG. 3 is a right end elevation view of the assembled sharpener.
FIG. 4 is a longitudinal section view through the sharpener taken along the line 4--4 of FIG. 3.
FIG. 5 is an exploded perspective view of the module cover plate and retention cap.
FIG. 6 is a planar inward end view of the cartridge module.
FIG. 7 is a longitudinal section view of the cartridge module taken along the line 7--7 of FIG. 6.
FIG. 8 is a planar outward end view of the cartridge module with the cover plate removed.
FIG. 9 is an exploded perspective view of the ejector pin, drive housing, clutch collar, cartridge block, and motor controlling contacts.
FIG. 10 is an exploded perspective view of the cartridge block and blades and a representative crayon.
FIG. 11 is a top plan view of the assembled cartridge block.
FIG. 12 is a transverse section view through the cartridge block, taken along the line 12--12 of FIG. 11.
FIG. 13 is a transverse section view through the cartridge block, taken along the line 13--13 of FIG. 11.
FIG. 14 is a transverse section view through the cartridge block, taken along the line 14--14 of FIG. 11.
FIG. 15 is an exploded side elevation view of the cartridge block, clutch collar, and drive housing.
FIG. 16 is a longitudinal section view through the assembly of FIG. 15, taken along the line 16--16.
FIG. 17 is a longitudinal section view through the assembled drive housing.
FIG. 18 is a plan view of the motor and drive train assembly.
FIG. 19 is an exploded side elevation view of the drive housing, electrical motor contacts, and the cartridge housing, shown with the contacts in the disengaged position.
FIG. 20 is an exploded side elevation view of the drive and cartridge housing shown with the electrical motor contacts in the engaged position.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring initially to FIGS. 1, 2, and 4, the subject sharpener assembly 10 is seen to comprise a lower housing 12, an upper housing 14, a lid 16, a handle 18, a cartridge module 20, a gear box housing 22, and a cover plate 24. The assembly 10 combines to form a hand carried portable crayon storage container having an integral battery powered crayon sharpener built therein.
The four sided lower housing 12 is molded from conventional plastics material by conventional means, and is defined by sidewalls 26, 28, and end walls 30, 32 projecting from a bottom floor surface 29 to an upper rim 31. Extending upward from within the housing, proximate the four corners, are four assembly sockets 34, each having an upwardly opening axial bore 35. A series of three parallel spacer walls 36 project upward from the floor 29 include upwardly concave upper edges 37. A bottom opening battery compartment 38 extends into the floor 29 as shown.
Formed within the end wall 30 at the top rim 31 is a semicircular pivot pin flange 40. Across from the flange 40, extending into the top rim 31 of the opposite end wall 32 is a semicircular opening 42.
The upper housing 14 is a four sided plastic molded form, having sidewalls 44 and end walls 46, 48. A semi-circular pivot post flange 50 projects outward form end wall 46 and extending upwardly into the opposite end wall 48 is a semi-circular opening 52 (FIG. 5). The housing 14 further includes an inner storage compartment 54 and a raised platform at one end of the compartment 54 that is formed to provide adjacent crayon holding channels 56. A through-bore 58 exists through the vertical wall 55 of the raised platform as shown.
The lid 16 is a concave body 60 formed from plastic by conventional means. The body 60 merges at opposite ends with raised shoulder portions 62, each having a handle socket recess 64 formed downward therein and a through slot 66 extending downwardly through the lid to an underside. The lid is configured to have an end flap portion 68 through which a circular hole 70 extends. The opposite lid side is formed having a larger end flap portion 72 through which a larger circular hole 74 extends.
The handle 18 is an elongate plastic form having a central grip portion 76 of inverted U-shaped cross-section, defined by side surfaces 78. Four dependent rectangular retention tabs 80 extend from the side surfaces 78, each having a locking flange 82 at a lower free end.
The components 12, 14, 16, 18, 20, 22, and 24 fit together to form the assembly shown in FIG. 1. The cartridge module and gear box housing 22 are cylindrical cans of plastic construction that are supported by the arcuate edges 37 of the lower housing support walls 36. So located, the locking cover 24 is adjacent the end wall 32. The upper housing attaches to the lower housing and includes like-shaped downwardly directed edges (not shown) that, with edges 37, encircle and entrap the components 20, 22. The upper housing further has dependent posts (not shown) that extend from an underside into the bores 35 of the support posts 34, whereby connecting the housings 12, 14 together.
So joined, the flanges 40, 50 of the housings 12, 14 form a circular pivot post extending outward from on end of the assembly, and the openings (FIG. 5) 42, 52 of the housings 12, 14 at the opposite end form a circular opening that communicates with an internal chamber defined by the components 12, 14. The lid is pivotally connected to the upper housing 14 by the placement of flap through hole 70 around the pivot post formed by flanges 40, 50, and flap through hole 74 around the circular opening formed by the openings 42, 52. Pivotally mounted lid 16 encloses the storage compartment 54 of the upper housing 14, and moves along an arcuate path between open and shut conditions. The handle 18 snaps into the upper sockets 64 of the lid 16, as tabs 80 project downward through lid slots 66 and the locking flanges 82 catch over an underside edge of the slots 66. The handle call then be used to transport the container or to rotate the lid into an open position.
With reference to FIGS. 2, 4, 5, and 7, it will be seen that the end flap 72 of the lid 16 is formed having an arcuate cutout channel 84 along the top perimeter hole 74. Intermediately positioned along the channel 84 is a rectangular notch 86. The notch 86 operates as a keyway for facilitating the removal of the cartridge module from the container as will be explained below.
The lock cover 24 is of a concave dish shape, having a radiussed outer wall 88. A slot 90 projects rearward from the outer wall 88 at the top, and a lip 92 projects rearward from wall 88 at the bottom. Proximate the slot 90, a cylindrical sleeve 94 projects rearward and throughbore 96 projects through the sleeve 94 from an outward surface of the wall 88. A rectangular alignment tab 95 projects outward from the peripheral edge of wall 88 and includes a locking flange 97 at the remote end thereof. Finger depressions 98 extend into the outward facing surface of the wall 88 to facilitate manual grasping and turnings of the cover 24.
Continuing, with reference to FIGS. 5, 6, 7, and 7, the subject crayon sharpening incorporates a removable cartridge module 100 that comprises a drawer housing 102, a pivotal drawer door 104, and a cartridge block 106. The drawer housing 102 is of plastic construction having an internal upper chamber 108 and a lower, shavings collection chamber 110, with chambers 108, 110 being separated by a horizontally extending, downwardly concave partition flange 112. The housing 102 has a forward wall interrupted by a forwardly projecting cylindrical sleeve 116 proximate a top end. The sleeve has forward ends 118 inwardly formed as shown. The cover 24 attaches to the housing 102 by two screws 119 as shown in FIG. 6 that fit into two counter bored bosses 117 (FIG. 8) on the drawer housing and into two screw bosses (not shown) in the rearward facing surface of cover 24.
A pair of spaced apart cylindrical pivot pins 120 extend from the sides of the drawer housing into the lower chamber 110 thereof The door component 104 is of plastic construction, preferably transparent, and comprises a forward wall 122 and a bottom wall 124 connected at a right angle. The door has a pair of pivot post sockets 126, 128 formed and located to capture the pivot posts 120 therein, making the door reciprocally rotatable about the posts 120. A latch 130 of U-shape configuration is provided having a reversely formed upper free end 132 and a locking flange 134 extending thereacross. The latch flange 134 catches over the lower edge of drawer housing front surface 114 to lock the door component 104 in an upright condition, below the upper chamber 108.
The door 104 can be freed to rotate clockwise by compressing the latch 130 sufficiently to enable free end and flange 132, 134 to clear the lower edge of the front wall 114. So freed, the door can rotate clockwise into an inverted condition, whereupon the shavings contents accumulated upon the door in an upright condition will be expelled. The phantom lines of FIG. 7 depict the inverted state. Thereafter, the door can be rotated counter clockwise until latch end 132 and flange 134 snap back over the lower end of wall 114. Thus, the drawer readily and conveniently can be emptied and returned to its original state. It will be appreciated that the cartridge module 100 shown in FIG. 7 is a self-contained assembly that is transportable by grasping the cover 24. Also, it will be noted that the cover 24 attaches to the outward edge of the housing 102 by means of two screws 119.
A protrusion 135 of elongate cylindrical configuration and having a rounded remote end, extends rearward from the housing surface 114 through an aperture 137 in module housing 20 as will be appreciated from FIGS. 6, 19, and 20. The protrusion 135 functions to apply a biasing force to the motor actuating contacts as will be explained below.
As seen from FIGS. 4, 7, 9, and 10, the cartridge block 106 seats lengthwise within the upper chamber 108 of the drawer housing 102. The block 106 comprises a cylindrical rearward sleeve 136 having conical outwardly projecting annular gear teeth 138 therearound and bore 140 therethrough; an intermediate larger diameter sleeve 142 adjoining the forward sleeve 136 and having a series of spaced apart retention ribs 144 therearound and extending lengthwise along the sleeve 136; and an outwardly directed semi-circular retention flange 146 at a forward edge of sleeve 136. Internally, the bore 140 terminates at an inward partition wall 148, and an aperture 150 that is coaxially aligned with the bore 140 proceeds through wall 148 to the forward side thereof.
A cutting station generally referenced at 152 exists forward of partition wall 148. The cartridge block 106 includes a central planar surface 154 extending forward from the flange 146, through which a centrally disposed elongate opening 156 extends. Opposite sides of the opening 156 comprise cutting blade edges 158, 160 that converge from a forward end to a rearward end of the station 152. The central planar surface 154 is flanked on both sides by sidewalls 162,164, and extends forwardly to a vertical, semi-circular mounting flange 166. A blade supporting pedestal 168 is positioned upon the surface 154 in abutment with the flange 166. The flange 166 has three apertures 170, 172, and 174 therethrough and a fourth aperture 173 extends through the surface 154 to one side of the central opening 156.
A forward cylindrical sleeve 176 extends from the flange 166 to a forward end of the cartridge block; the sleeve 176 having a coaxial bore 178 extending from the forward end of the cartridge block backward to the inner partition wall 148 as best seen in FIG. 7. The bore 178 has a rearward end portion that extends through the cutting station 152 and is of circular dimension in cross section, diametrically sized to closely admit a standard sized crayon.
A secondary blade 180 is provided that flat, horizontally oriented body 182 and a beveled cutting edge 184 that projects into the bore 178 and is oriented offset from yet parallel to the major axis of the cartridge block bore 178. The blade body 182 has a central through aperture 186. A preparatory blade 188 is further provided that has a flat, vertically oriented square shaped body 190 and a lower cutting edge 192 that extends into the bore 178 and is oriented transverse to the major axis of the cartridge bore. The body 190 has a step 194 formed in a lower corner adjacent to the cutting edge 192 and a centrally disposed through aperture 195.
A blade retainer 196 is provided having a flat elongate center portion 206; stepped end portions 198, 200, and central mounting apertures 202, 204 extending through portions 198, 200. A horizontal cantilever flange 208 extends forward from an upper edge of portion 206 and a horizontal cantilever flange 210 extends rearward from a lower edge of portion 200. Flange 210 has a downwardly formed free end 212. Four assembly eyelets 214 are provided, each having a circular head 216 and a central cylindrical shank projecting therefrom.
Assembly of the blades to the cartridge block will be understood from FIGS. 10, 11, 13, and 14. The blade 180 is positioned upon the cartridge block surface 154 with the flat forward edge of the blade against the flange 166, the aperture 186 in alignment over the aperture 173, and the side facing edge of the blade 180 against the sidewall 164. So positioned, the cutting edge 184 projects into the axial bore and bevels outwardly therefrom toward the rear of the cartridge block surface 154. A forward portion of the cutting edge 184 projects forward beyond the forward end of the cutting edges 158, 160. The cutting edge 184 is parallel to and offset from the central axis of bore 178. One eyelet 214 is inserted through aligned apertures 186, 173 to secure the blade 180 to surface 154.
The blade 188 is likewise assembled to surface 154, with the forward facing side of body 190 abutting the flange 166, step 194 brought to rest upon the support 168, and aperture 195 aligned over aperture 172. The lower cutting edge 192 depends into the upper portion of the axial bore and is oriented perpendicular to the axis of the axial bore. One eyelet 214 extends through apertures 195, 172 to secure blade 188 to surface 166.
The blade retainer 196 provides means for attachment of the blades 180, 188 to the surface 154. The retainer 196 is positioned upon the surface 154 with the tab 212 inserted down into the eyelet 214 within apertures 186, 173, and retainer tab 208 projecting, through the aperture 172 of flange 166. At the opposite end of the retainer, center portion 206 overlaps the blade 188 and the flange 166, and apertures 202 and 170 are in alignment and receive one eyelet 214 to secure the retainer 196 to the cartridge block. The final eyelet is inserted through aligned apertures 204 of the retainer and 174 of the flange 166. The retainer and the eyelet serve as mutually redundant connections for attachment of the blades 180,188 to the cartridge block. Together, the retainer 196 and eyelets 214 ensure that the blades 180, 188 will not move through use from their intended positions on surface 154, 166.
The assembled cartridge block, retainer, and blades, are received within the cartridge module 100 as will be appreciated from a combined consideration of FIGS. 7 and 10. The cartridge block 106 assembles from the forward end of the drawer housing 102, residing in the upper chamber 108 thereof. Upon insertion of the cartridge block 106, the intermediate sleeve 142 of the block 106 resides within the cylindrical socket 116 of housing 102, and the sleeve 136 projects from the rearward housing end 118 with clearance. It will be noted that the gear teeth 138 of sleeve 136 are spaced inward from the housing end 118 and that a circumferential gap exists about the block sleeve 136. The retention ribs 144 of block sleeve 142 extend into close proximity to the sidewalls of socket 116 and cannot clear the inwardly formed end 118 to thereby prevent the cartridge block from exiting the rearward end of the drawer housing 102.
The cylinder sleeve 94 of the cover member 24 captures the forward sleeve 176 of the cartridge block 106 therein with nominal clearance as shown. Spanning, the upper chamber 108, the cartridge block is free at both ends and along its intermediary length to rotate about the longitudinal axis thereof. The bore 178 of the block 106 coaxially aligns with the bore 96 of the cover member 24. The distance between the forward end of the bore 178 and the inner partition wall 148 at the rearward end of the cutting station 152, and the diameter of the coaligned bores 96, 178 are designed to accommodate the axial receipt of a standard crayon therein.
As depicted in FIG. 10, a crayon 220 of the type commonly used is manufactured by a molding process to include an inner cylindrical core of colored wax, plastic, or the like 222, an outer jacket 224 of paper or plastic, and a frustroconical nose 226 that terminates at a circular nose end surface 228. The crayon end surface 228 is ideally suited for coloring in that it applies a relatively wider band of color with each stroke that achievable with a sharpened point.
Referring to FIGS. 4, 9, 15, 16, and 17, a clutch collar 230 is shown having a cylindrical body 232; a throughbore 234 extending through body 232; a pair of diametrically opposite peripheral arched flanges 236, 238; and a radiussed lobe projection 240 directed outward from each flange 236, 238. The internal surface of the body 232 includes an annular ring of gear teeth 242. A cylindrical drive housing 244 is configured having, a main body 246 and a frontal annular bore 248 extending inward into the body 246 to an internal partition wall 247. An annular rearward bore 249 is provided on the rearward side of wall 247 and extends rearward to a rearward end of body 246. An outwardly projecting annular flange 250 extends about body 246 proximate the forward end thereof. An axial sleeve 252 extends through the body 246, with a forward sleeve end 254 projecting beyond the forward end of body 246 and a rearward sleeve end 259 projects beyond the rearward end of the body 246. An aperture 256 extends through the forward sleeve end 254 and an axial through bore 258 extends through the sleeve 252 from the rearward end 259 to the forward end 254 and communicates with the aperture 256.
A ring of internal annular gear teeth 260 circumscribe an inner wall of the housing 244 in the forward bore 248 and a ring of outward directed annular gear teeth 262 circumscribe the outer surface of the housing 244 proximate the rearward housing end.
A circular ring 264 is positioned within the rearward bore 249, having a body 265 and a throughbore 266. The ring body 265 has an annular forward facing channel 268 adapted to receive and seat a helical compression spring 270 and to press the spring against the internal surface of chamber 249. An ejector pin 272 is shown to comprise a forward segment 274 terminating at a circular forward end surface 275; an annular retention collar 276 positioned axially rearward of the forward segment 274; an elongate main body segment 278 terminating at a rearward end 280. A helical compression spring 282 receives the rearward end 280 therethrough and is positioned against the forward collar 276. An end cap 284 having a central socket 286 receives the rearward end 280 of the ejector pin 272 therein to prevent separation of the spring 282 therefrom.
Referring to FIGS. 2, 9 and 18, a motor 288 is mounted to the gear box housing 22 and lead 290 electrically connects the motor 288 to contact 300 and lead 292 goes from the motor to the battery compartment 38. Motor 288 is a conventional drive motor that is common in the industry and operates on 4 "AA" alkaline batteries that are stored and electrically connected with the compartment 38. The electric motor 288 drives a worm gear 294 that meshes with and drives a combination gear 296. The gear 296 in turn meshes with and drives a spur gear 298 that engages and drives the outward gear teeth 262 of the drive housing 244. The gear train described above thus mechanically rotates whenever the motor 288 is actuated and rotational movement of the drive housing 244 stops whenever the motor 288 is deactivated.
The switching of motor 288 between the on and off modes occurs via two separate electrical contacts 300 and 302 that are positioned adjacent to one another but electrically isolated by an insulation spacer 304. Contact arm 300 is L-shaped and includes a mounting aperture 306 and a remote contact tip 308. The spacer 304 is likewise L-shaped and includes an aperture 310; and L-shaped contact arm 302 is provided with mounting aperture 312 and includes a remote contact end 314.
The position of the contact arms relative to the drive housing 244 will be understood from FIGS. 9, 18, 19, and 20. The contact arm 302 is longer that the contact arm 300 and the remote end of arm 302 is positioned forward and adjacent to the peripheral flange 250 of the drive housing 244. The protrusion 135 of the drawer housing 102 projects from surface 114 through an aperture 137 in the cartridge housing 20 and presses against the contact 302, biasing the contact 302 against contact 300. Whenever the drive housing is in the rearwardly biased position, as shown in FIG. 20, the spring 270 is compressed, and the contact end 308 of contact arm 300 is in electrical contact with the contact arm 302 and a circuit is established therethrough which activates the drive motor 288. However, when in the forward, or released position, as depicted in FIG. 17 and 19, spring 270 will exert a forward force and move the drive housing 244 forward and flange 250 of the housing will contact and force the remote end 314 of contact 302 forward, whereby breaking electrical contact between the contacts 300, 302, and disabling the motor 288. The force exerted by housing 244 against contact end 314 causes end 314 to resiliently flex about the remote end of protrusion 135, breaking the connection with contact 300. As will be explained below, the housing 244 moves axially rearward responsive to a crayon inserted into the cartridge block to activate the motor and returns to a forward axial position in the absence of a crayon to deactivate the motor 288.
With reference to FIGS. 4, 7, 9, and 17, the operation of the subject sharpener will be explained. The clutch collar 230 is coaxially seated within the drive housing 244, with the housing center sleeve 252 projecting through the clutch collar 230 and the inward gear teeth 260 of housing 244 meshing with the lobe projections 240 of the clutch collar. The gear teeth 262 of the housing 244 mesh with the drive gear train as described above. The housing 244 reciprocates axially along the ejector pin 272 between a forward position, shown in FIG. 17, in which compression the spring 270 is relaxed and exerts no biasing force on the housing 244, and a rearward position in which the compression spring 270 is compressed against the inward surface of housing 22.
The cartridge block 106 is rotationally seated within the removable cartridge drawer assembly 100. As the assembly 100 is inserted into the cartridge module 20, the leading end of the cartridge block sleeve 136 enters into the clutch collar 230 and a leading portion of the cartridge block gear teeth 138 mesh with the internal gear teeth 242 of the clutch collar. The cartridge block 106 reciprocates axially along the major axis of the housing cylindrical socket 116 a small distance indicated in FIG. 7 at 316. Axial movement in the rearward direction is initiated when a crayon 220 is inserted axially into cartridge block bore 178 and a forward end of the crayon contacts sharpening, edges 158, 160. Pushing the crayon inward causes the cartridge block forward gear teeth 138 further into the clutch collar teeth 242 and pushes the drive housing 244 axially rearward. Rearward movement of housing 244 causes spring 270 to compress, the peripheral flange 250 to disengage from the motor contact arm 302, and the contacts 300 and 302 to re-engage. With the re-engagement of contacts 300 and 302, motor 288 is activated and begins rotation of the housing 244 through worm gear 294 combination gear 296, and spur gear 298.
Rotation of housing 244 causes rotation of the clutch collar 230 as lobes 240 are rotationally driven by gear teeth 260. The rotation of clutch collar 230 in turn causes the cartridge block 106 to rotate about its longitudinal axis as clutch teeth 242 drive the cartridge block teeth 138. Rotation of the cartridge block 106 causes rotation of the sharpening blades 158, 160, 180, 188 relative to the forward nose of the crayon 220. The vertical blade 188 scores the circumference of outer jacket 224 proximate the forward end as it rotates and the horizontal blade 180 initiates a horizontal annular cut into the forward end of the crayon as it rotates, stripping away the outside crayon jacket back to the cut made by vertical blade 188. Contemporaneously, the rotating blades 158, 160, oriented to converge from front edge to rearward edge, carve the nose portion 226 into a conical form. The shavings resulting from the cutting blades fall between the blades 158, 160 into the upper drawer chamber 108, thence onto the downwardly concave flange 112, and thereafter fall off into the lower drawer chamber 110 and onto the lower door panel 124.
The subject invention incorporates means for disabling the rotation of the cartridge block 106 whenever an article harder than a crayon, such as a pen or pencil, is inserted into the cartridge block bore by mistake. As will be appreciated from the configuration of the clutch collar lobes 240 and the drive housing internal gear teeth 260, shown in FIG. 18, rotation of the clutch collar by the drive housing will occur only at a relatively low torque loading level. A higher torque loading will cause the lobes 280 to slip over the housing gear teeth 260, preventing the rotation of the collar 230 and the cartridge block 106 therein. For example, if the cartridge block is loaded with a harder object such a pencil, a larger torque will be required to turn the blades 158, 160, 180, 188 against the object. However, the torque required to rotate the cartridge block 106 will exceed the preset torque limits designed into the clutch collar lobes 240 and rotation of the clutch collar and cartridge block will be inhibited. Thus, the subject sharpener incorporates a fail-safe mechanism for disabling the rotation of the sharpening blades against an object that is harder than the relatively soft crayon for which the sharpener was designed.
Removal of the crayon after it has been sharpened from the cartridge block releases earward pressure on the cartridge block 106 and drive housing 244, freeing spring 270 to direct a forward force on the housing 244 and cartridge block 106. Forward movement of housing 244 causes flange 250 to re-enrage motor contact arm 302, separating it from contact arm 300, whereby breaking the motor circuit and deactivating the motor. Consequently, rotation of housing 244 terminates and with rotation of the cartridge block 106. Insertion of a crayon into the cartridge block 106 thus initiates rotation of the cartridge block by engaging the motor 288 and withdrawal of the crayon terminates the rotation of the cartridge block 106 by electrically breaking the circuit of the motor 288.
The contact between contacts 300 and 302 is also broken by the removal of the shavings drawer assembly 100 from the sharpener housings. As the assembly is withdrawn, the spring 270 causes the drive housing 244 to move axially forward, causing peripheral flange 250 to engage contact 302 and break electrical engagement between contact 302 and 300, whereby disabling the motor 288. Thus, removal of the drawer assembly 100 effectively disables the drive motor and prevents actuation of the drive assembly during its absence.
The manner of removal of the drawer assembly 100 will be appreciated from consideration of FIGS. 5 and 6. The cover 24 of the drawer assembly 100 is provided with the lock tab 95, located at approximately the ten o'clock position. The lid 16 of the sharpener has a channel 84 formed in a peripheral edge of the opening 74, and a notch 86 is located within the channel at the twelve o'clock position. In order to remove the drawer assembly 100, the lid 16 must be rotated until the notch 86 aligns with the cover member tab 95, whereupon the cover member 24 and the drawer assembly 100 may be pulled out of engagement with the sharpener case. Replacement of the drawer assembly occurs in reverse sequence. That is, the lid 16 must be rotated so that the notch 86 is in the ten o'clock position so that the drawer assembly cover tab 95 can be inserted therethrough. The lid 16 is thereafter rotated into an upright position and tab 95 is trapped against the inside surface of channel 84.
The removal of the drawer assembly 100 most frequently is for the emptying of shavings from the lower housing chamber 110. To effectuate removal, the latch end 132 is pushed down and in, causing the flange 134 to clear the lower end of wall 114. The lower door 104 can thereafter be rotated clockwise into an inverted position and its shavings contents emptied. It will be noted that with the door 104 open, the blade area of the cartridge block is digitally inaccessible because of the presence of flange 112. A child, therefore, cannot reach into the blade area and inadvertently be injured.
A second reason for removal of the drawer assembly 100 is to replace the blades 158, 160, 180, or 188. Also, if the forward end of the crayon breaks off during the sharpening procedure and cannot be dislodged by the ejector pin as explained below, the cartridge block can be accessed by removal of the drawer face 114 by the loosening of two captive screws (not shown) and freeing the cartridge assembly for replacement or cleaning.
The ejector pin 272 as seen in FIGS. 4, 7, and 9, extends through sleeve 252 of the drive housing 244 and the forward pin segment 274 projects through the aperture 256 in the sleeve end wall 254. The spring 282 is received over the ejector pin segment 278, and abuts the annular collar 276 at a forward end, and seats within an annular channel 318 at a rearward end. The rearward end 280 of the ejector pin projects through the through bore 58 within the wall 55 of the upper housing 14 and has end cap 284 secured thereover. As such, the end 280 of the ejector pin is digitally accessible from the storage compartment 54 of the upper housing 14.
The forward end 274 of the pin 272 extends through the sleeve end wall 254 and through the inner partition wall 148 of the cartridge block as shown in FIGS. 7,9, 16, and 17. The forward circular end surface 275 of the pin 272 projects through end wall aperture 255 and into the cutting station 152. As the crayon is inserted into the cutting station 152 and is sharpened, the forward nose surface of the crayon will abut the forward end surface 275 of the pin 272 and take a circular form. The ejector pin 272 will be pushed by the crayon axially rearward, compressing the spring 282. After the sharpened crayon is removed, the spring 282 will force the pin 272 forward end surface 275 will push any residual crayon shavings or any small broken crayon pieces from cutting station 152 and they will drop out. If the pieces lodged in the cutting station 152 are of a larger size, the ejector pin may be forced axially forward by digitally pressing the rearward end 280 of the pin forward from within the storage compartment 54 of the upper housing 14. If that proves unsuccessful, the drawer assembly 100 can be removed and the cartridge block accessed and serviced.
From the foregoing it will be appreciated that the subject invention functions to restore the forward tip of a crayon to its manufactured state. The outer jacket of the crayon is scored by the vertical blade 188, referred to as the preparatory blade, and the horizontal blade 180 lifts the paper and peels it away and in so doing cuts an annular shoulder 223 into the forward end. The convergent blades 158, 160 form a conical nose to the crayon and elector pin forward end surface 275 gives the crayon tip a circular flat nose end surface that is optimal for coloring purposes. The blades 180, 188 are formed of steel for durability since repeated cutting through the jackets of crayons can dull plastic blades. The blades 158, 160 are of plastic construction since they encounter only soft core material.
The safeguards incorporated in the subject invention are apparent from the forgoing. First, the motor will be automatically engaged when the crayon is inserted into the cartridge block and therethrough forces the drive housing rearward. Removal of the crayon causes the motor to automatically disengage in reverse manner. Secondly, the insertion of a harder object, such as a pen or pencil, into the cartridge bore will cause the clutch collar to slip out of meshing engagement with the drive housing, whereby preventing the cartridge block blades from rotating against the harder object. The softer crayon, however, will not cause such slippage and the clutch collar will remain in engagement with the drive housing and be rotated thereby.
Thirdly, the subject motor is disabled by the removal of the drawer assembly 100, an additional safeguard. The drawer assembly further facilitates easy removal of shavings through a bottom dropping door and incorporates an internal flange to render the cartridge block blades inaccessible to fingers when the bottom door is open. Lastly, the subject invention incorporates a self-ejecting pin for dislodging broken crayon pieces from the cutting station.
While the preferred embodiment of the subject invention has been described above, the invention is not intended to be limited thereto. Other embodiments that will be apparent to those skilled in the art and which utilize the teachings herein set forth, are intended to be within the scope and spirit of the subject invention. | A crayon sharpening assembly is disclosed comprising an axially rotating cartridge block (106) having an axial bore (178) for axial receipt of a crayon with a forward end of the crayon positioned within a cutting station (152). A pair of convergent sharpening blades (158, 160) carve a conical nose into the forward crayon end; a secondary horizontal blade (180) engages the forward crayon end and cuts an annular stepped shoulder surrounding the conical nose; and a preparatory vertical blade (188) makes a vertical circumscribing cut through the jacket of the crayon proximate the forward end, whereby restoring the forward crayon end into its manufactured form. A carrying case (12, 14) is provided having a pivotal lid (16), with the sharpener drive assembly (20, 22) built into one end wall. A drawer assembly (100) is removable from the end wall and contains the cartridge block (106) and a housing (102) for collecting shavings generated in the sharpening procedure. A bottom housing door (104) opens to allow expulsion of the shavings. Rotation of the cartridge block (106) is facilitated by an electrically driven drive assembly that is automatically engaged and disengaged by the respective insertion and removal of the crayon and disengaged by the removal of the drawer housing assembly. Rotation of the cartridge block (106) is defeated by a clutch member (230) whenever an article that has a hardness greater than that of a crayon is inserted into the cartridge block cutting station (152). | 44,051 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates in general to means for stably supporting an object and more specifically to a self-contained, adjustable support device having a collapsed position for storage and/or transport and having an open position for providing stable supporting surfces for a wide variety of objects.
2. Description of the Prior Art
Heretofore, various devices have been used by carpenters and other workmen to support workpieces as the workpiece is cut, filed or otherwise worked on. Typically, such workmen use a pair of sawhorsed or tesles to support a workpiece or the like. However, typical sawhorses and tresles are often disadvantageous because they are typically not adjustable or collapsable and often do not have adequate strength. Other disadvantages include bulkiness, storage and transport difficulty and a tendency to become weakened through repeated use. Further, additional support means such as transverse rails and the like must be used in conjunction with such typical sawhorses and tresles when supporting small, large, odd shaped, or flimsey objects. A preliminary patentablility search in class 248, subclass 439 and class 182, subclasses 153, 154, and 155 produced the following patents: Fassler, U.S. Pat. No. 965,173; Varache, U.S. Pat. No. 1,150,794; Beland, U.S. Pat. No. 1,298,867; Tyler et al, U.S. Pat. No. 1,860,875; Strand, U.S. Pat. No. 1,876,787; Bowers, U.S. Pat. No. 2,897,911; Barthel, U.S. Pat. No. 3,817,349 and Hendrickson et al, U.S. Pat. No. 3,945,328. None of the above patents or prior art devices disclose or suggest the present invention.
SUMMARY OF THE INVENTION
The present invention provides a support device of general utility value, particularly useful to work men for supporting workpieces such as lumber or other objects for sawing, drilling, painting, repair and the like. The support device of the present invention comprises, in general, a support beam; leg structure; and bracket means pivotally attaching the support beam to the leg structure, the bracket means including pivot rod means extending through the beam member for allowing pivotal movement relative thereto, support means rigidly mounted relative to the pivot rod means for supportingly engaging the beam member, and attachment means rigidly mounted relative to the pivot rod means and the support means for attaching the pivot rod means and support means to the leg structure.
An object of the present invention is to provide a new and improved support device which is substantially compact, easily adjustable, collapsable, storable, transportable, and adequately strong, that does not become weak or wobbly through use, and that is substantially self-stabilizing on uneven floor or ground conditions.
Another object of the present invention is to provide a latch bracket which will lock a pair of legs to a central beam either in a legs extended position or a legs collapsed position, and which will allow each pair of legs to be adjusted to various positions along the beam.
An additional object of the present invention is to provide a support device which can be used as an individual means for support small, large, odd shaped, or flimsey objects by means of providing multiple support surfaces lying in substantially the same plane, thus eliminating the need for multiple support devices and/or supplemental support means for such objects and for supporting such objects in a way that a workman is not limited or hindered in access to the supported objects by the support device itself.
Another object of the present invention is to provide means for out-of-the-way storage of tools and the like.
Still another object of the present invention is to provide a construction of the support device which is simple, practical and economical to manufacture and to use.
Many other objects, advantages and/or features of the present invention will be at once apparent or will become so as the preferred embodiment of the present invention is hereinafter described.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the support device of the present invention.
FIG. 2 is a perspective view of a bracket means of the support device of the present invention.
FIG. 3 is a perspective view of a leg means of the support device of the present invention with certain portions of the support beam structure shown in broken lines.
FIG. 4 is a perspective view of a thumbscrew of the support device of the present invention.
FIG. 5 is a perspective view of strut of the support device of the present invention with certain portions of the support beam structure and leg means shown in broken lines.
FIG. 6 is a side elevational view of the support device of the present inention with portions thereof broken away for clarity.
FIG. 7 is similar to FIG. 6 but with the leg means thereof in folded, collapsed positions.
FIG. 8 is a top plan view of FIG. 7.
FIG. 9 is a somewhat diagrammatic sectional view of a portion of the support device of the present invention showing certain features of the first bracket means, the first leg means and support beam.
FIG. 10 is similar to FIG. 9 but shows the leg means in a folded, collapsed position.
FIG. 11 is a sectional view substantially as taken on line XI--XI of FIG. 9.
FIG. 12 is a sectional view similar to FIG. 11 but showing the bracket means in a moved position.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The preferred embodiment of the support device 11 of the present invention as clearly shown in FIG. 1 includes a support structure or means 12 that includes an elongated longitudinal support beam member 13 having an upper surface 13' and a lower surface 13" (see FIGS. 11 and 12) and having a first end 15 and a second end 17; a first leg structure or means 19 for supporting the first end 15 of the support beam member 13; and a second leg structure or means 21 for supporting the second end 17 of the support beam member 13 (see, in general, FIG. 1). A first bracket means 23 is provided to attach the first leg means 19 relative to the first end of the support beam member 13 and a second bracket means 25 is provided to attach the second leg means 21 relative to the second end 17 of the support beam member 13. The first and second bracket means 23, 25 are constructed so as to allow the first and second leg means 19, 21 to move between an extended, in use or open position with the leg means 19, 21 positioned substantially perpendicular to the support beam member 13 (see FIGS. 1, 6 and 9), and a collapsed, closed or stored position in which the leg means 19, 21 are positioned substantially parallel with the support beam member 13 (see FIGS. 7, 8 and 10).
The first leg means 19 preferably includes an inverted substantially U-shaped body member 27 having a first leg 29 with a first end 31 and a second end 33, a second leg 35 with a first end 37 and a second end 39, and a web or bight portion 41 extending between the second end 33, 39 of the first and second legs 29, 35 (see, in general, FIG. 3). The body member 27 is preferably constructed of an elongated length of metal tubing which may be bent or otherwise formed to the inverted U-shape as will now be apparent to those skilled in the art. Thus, for example, the body member 27 may be constructed out of 18 gauge 3/4 inch by 11/2 inch rectangular metal tubing. A generally horizontal cross member 43 preferably extends between the first and second legs 29, 35 at a point between the first and second end thereof substantially parallel to the bight portion 41. The cross member 43 is preferably constructed of metal tubing and may be welded or otherwise fixedly attached to those skilled in the art. Thus, for example, the cross member 43 may also be constructed of 18 gauge 3/4 inch by 11/2 inch rectangular metal tubing. A strut 45 preferably extends bewteen the cross member 43 and the bight portion 41.
The strut 45 (see FIG. 5) is preferably channel-shaped having a first side portion 47 having an aperture 48 therethrough, a second side portion 49 having an aperture 50 therethrough, and a back portion 51 extending between the first and second side portions 47, 49. An aperture 52 is provided through the back portion 51 for reasons which will hereinafter become apparent. The aperture 52 is preferably adapted to screwably receive a threaded shaft as will hereinafter become apparent. Thus, the aperture 52 may be threaded as will be apparent to those skilled in the art or a threaded nut 52' (see FIGS. 9 and 10) may be fixedly attached to the back portion 51 concentrically of the aperture 52, etc. The strut 45 preferably has a notch 53 therein for receiving the bight portion 41 of the body member 27 as clearly shown in FIG. 3, thus allowing the upper ends or ears 47', 49', of the first and second side portions 47, 49 to extend above the bight portion 41 for reasons which will hereinafter become apparent. The strut 45 is preferably constructed of 14 gauge sheet metal or the like and may be easily cut and bent into the desired shape. The strut 45 may be fixedly attached to the cross member 43 and bight portion 41 in any manner now apparent to those skilled in the art such as by being welded thereto. Shoes 55 constructed of plastic or the like may be secured ot the first ends 31, 37 of the first and second legs 29, 35.
The second leg means 21 is preferably substantially identical in construction and function to the first leg means 19 and the above detailed description of the first leg means 19 should be referred to for a complete understanding of the second leg means 21. Similar parts and elements of the first and second leg means 19, 21 bear the same reference numerals in the drawings.
The first bracket means 23 (see, in general, FIG. 2) includes a pivot rod means 57 extending through the beam member 13 (see FIGS. 11 and 12) for allowing pivotal movement relative thereto. The first bracket means 23 also includes support means 59 rigidly mounted relative to the pivot rod means 57 for supportingly engaging the beam member 13, and attachment means 61 rigidly mounted relative to the pivot rod means 57 and the support means 59 for removably attaching the pivot rod means 57 and support means 59 to the first leg means 19. Preferably, the first bracket means 23 is constructed primarily of heavy gauge metal having a body portion 63 bent at one end to form a flange 65 having a slot 67 and outwardly angled distal ends 68 for defining the attachment means 61 in a manner which will hereinafter become apparent, and bent at the other end to form a first flange 69 and a second flange 71 which coact to define the support means 59 in a manner which will hereinafter become apparent. As clearly shown in FIGS. 2, 9 and 10, the outer faces of the first and second flanges 69, 71 are located perpendicular to one another for reasons which will hereinafter become apparent. The body portion 62 may have one or more strengthening or reinforcing flanges 72 (see FIGS. 11 and 12) extending the length thereof to increase the strength and stability of the bracket means 23 as will now be apparent to those skilled in the art. The pivot rod means 57 may consist simply of an elongated rod 73 such as a typical bolt or the like having a first end 75 fixedly secured to the body 63 by welding or the like and having a second end 77. The second end 77 of the rod 73 preferably has a transverse aperture 79 therethrough for removably receiving a hitch pin clip 81 or the like for reasons which will hereinafter become apparent.
The second bracket means 25 is preferably identical in construction and function to the first bracket means 23 and the above detailed description of the first bracket means 23 should be referred to for a complete understanding of the second bracket means 25. Similar parts and elements of the first and second bracket means 23, 25 bear the same reference numerals in the drawings.
The support beam member 13 preferably consists of an elongated length of lumber such as a typical "two by four" or the like. Transverse apertures 83 are provided through the support beam member 13 for allowing the rod 73 of the pivot rod means 57 of each bracket means 23, 25 to pass therethrough. Preferably, a plurality of spaced apart apertures 83 are provided along the length of the support beam member 13 to allow adjustment of the leg members 19, 21 toward and away from one another as will be apparent to those skilled in the art.
The support means 12 preferably includes structure for defining a pari of elongated, transverse support beam members located one substantially adjacent each end 15, 17 of the longitudinal support beam member 13 and positioned substantially transverse thereto. The transverse support beam members may be defined merely by the upper surfaces of the bight portions 41 of the first and second leg means 19, 21. Preferably, however, the transverse support beam members include a plurality of slats 85 for being fixedly attached to the upper surfaces of the bight portions 41 of the first and second leg means 19,2 1 as clearly shown in FIG. 1. Each slat 85 preferably consists of an elongated lumber such as a typical "two by four" or the like and is preferably fixedly attached to the respective bight portion 41 by lag screws 87 or the like with the upwardly extending ears 47', 49' of the side portions 47, 49 acting as end stops for the slats 85 (see FIG. 3). Thus, the upper surface 13' of the longitudinal support beam member 13 and the upper surfaces of the slats 85 are planar relative to one another whereby an object can be stably supported on the support means 12 even if it extends across the beam member 13 and one or more slats 85. The support means 12 is thereby defined by an elongated longitudinal surface having first and second ends, a first transverse surface extending across the longitudinal surface adjacent the first end thereof, and a second transverse surface extending across the longitudinal surface adjacent the second end thereof, with the longitudinal and transverse surfaces planar to one another and with the transverse surfaces located intermediate the first and second ends of the longitudinal surface.
The attachment means 61 preferably includes a thumbscrew 89 (see, in general, FIG. 4) having a threaded body 91 for extending through the slot 67 in the flange 65 of the body 63 and into the threaded aperture 52 in the strut 45 to couple the respective bracket means 23, 25 to the respective strut 45. The thumbscrew 89 preferably has a head 93 for allowing it to be easily turned and a flange 95 for acting as a stop against the flange 65.
To connect the first leg means 19 to the support beam member 13 with the first bracket means 23, the support beam member 13 is positioned on the strut 45 between the upwardly extending ears 47', 49' of the first and second side portions 47, 49 thereof and with surface 13" adjacent to the upper surface of bight portion 41 of the bodymember 27, with one of the apertures 83 through the support beam member 13 aligned with the apertures 48, 50 through the first and second side portions 47, 51 of the strut (see, in general, FIG. 11). Then the rod 73 of the pivot rod means 57 is inserted through the aligned apertures 48, 50, 83. Once the rod 73 is inserted through the apertures 48, 50, 83, the hitch pin clip is inserted through the aperture 79 of the rod 73 to prevent inadvertent removal of the rod 73 from the apertures 48, 50, 83. the body 63 of the bracket means 23 can then be positioned so that the flange 65 is positioned adjacent to the threaded aperture 52 in the back portion 51 of the strut 45 with the slots 67 extending about the body 91 of the thumb screw 89 and with the flange 71 engaging the bottom of the beam member 13 (see FIG. 9). The thumb screw 89 can then be tightened to cause the support means and pivot means of the bracket means 23 to coact to wedge the support beam member 13 therebetween. More specifically, as the thumb screw 89 is tightened, the flange 95 thereof will cause the bracket means 23 to pivot somewhat about the pivot rod means 57 to cause the flange 71 to exert force against the lower surface 13" of the support beam member 13 (see FIG. 9) causing the lower surface 13" of the support beam member 13 to push against the bight portion 41 of the body member 27 while the lower radial surface of the rod 73 will exert force against the lower radial surface of the aperture 83. The outwardly angled distal ends 68 of the flange 65 will then coact with the wedge like force being applied to ensure that the bracket means 23 remains in position.
When the support device 11 is thus set up in the operative position with both leg means 19, 21 properly locked in place by way of the first and second brackets means 23, 25 respectively, the support device 11 will be structurely stable. Even if the support device 11 is set up on an uneven floor or ground surface, the construction allows the support device 11 to flex slightly and remain substantially stable.
To collapse the support device 11, the thumb screw 89 is loosened several turns. This will relieve the locking forces at the joint and allow the body 63 to be laterally moved to a position that by the time the hitch pin clip 81 comes in contact with the side portion 49 of strut 45, the flanges 65, 69, 71 are disengaged from the strut 45 and the beam member 13 respectively to allow the body member 27 to be rotated to a collapsed position (see FIG. 12).
To lock the body member 27 in the collapsed position, the body 63 is again moved laterally to position the flange 65 over the threaded aperture 52 and the thumb screw 89 is then tightened with the flange 69 engaging the upper surface 13' of the beam member 13 (see FIG. 12) to thereby lock the body member 27 in the collapsed position.
A board 97 or a similar member may be positioned across the crossmembers 43 of the leg means 19, 21 when in the extended position as clearly shown in FIG. 6 to provide a shelf or the like for out-of-the-way storage of tools and the like.
It should be noted that the first and second legs 29, 35 of the second leg means 21 may be spaced slightly farther apart from one another than the first and second legs 39, 25 of the first leg means 19 to allow portions of the first leg means 19 to nest within portions of the second leg means 21 when the support device 11 is in the collapsed position as clearly shown in FIG. 8.
From the above, it will be seen that all the recited objects, advantages, and features of the present invention have been demostrated as achievable in a highly practical and economical to manufacture and use embodiment of the present invention.
Although the present invention has been described and illustrated with respect to a preferred embodiment thereof and a preferred use therefore, it is not to be so limited since changes and modifications can be made therein which are within the full intended scope of the invention. | A self-contained adjustable support device designed to provide stable work supporting surfaces for a wide variety of objects in the legs extended position and also provides a legs collapsed position for storage and/or transport. The support device includes a pair of latch brackets with each latch bracket constructed to lock a pair of legs to a central beam either in the legs extended position or the legs collapsed position; and to allow each pair of legs to be adjusted to various positions along the beam. | 19,339 |
BACKGROUND
[0001] 1. Field of the Invention
[0002] The present invention relates to detecting redirection or interception of data and in particular to a method of detecting a redirecting process in the course of a bi-directional non-contact making transmission of data.
[0003] 2. Description of the Related Technology
[0004] Systems for the bi-directional non-contact making transmission of data are preferably used in identification systems. In general, these systems consist of a base station and a transponder. These systems are utilised for authentication purposes in the field of motor cars, a main field of usage. In order to achieve a high level of security for the authentication process, the distance over which the communication can take place is restricted to just a few meters in the case of a so-called “passive entry” system, i.e. the opening of a vehicle by pulling the door handle. In an identification system, it is important that the time required for the authentication process be kept short. The total time for the authentication process in the field of motor vehicles is generally between 50 and 130 msec. In order to prevent unauthorised authentication by means of a redirecting process for example, methods have been developed for detecting the manipulation and for terminating the authentication process should this be necessary.
[0005] A first method of detecting redirection or interception during an authentication process is known from German patent document DE 10005503, wherein at least one characteristic parameter of the transmitted electromagnetic wave is altered in reversible manner. To this end, a reply signal, which, for example, has been altered in frequency relative to the interrogation signal in a second transmitting and receiving unit (a transponder), is transmitted back to the first transmitting and receiving unit. In the first transmitting and receiving unit (the base station), the frequency of the reply signal is changed back again and compared with the frequency of the originally transmitted interrogation signal. If the value detected thereby lies within a pre-defined interval, one can virtually exclude the possibility that redirection has occurred.
[0006] Another method of detecting redirection in the course of an authentication process is known from German patent document DE 198 27 722. In order to prevent unauthorised opening of a motor vehicle, the power of the transmitted interrogation signal and that of the reply signal are bit-modulated. The mask used for the modulation process is produced by means of a secret key which is known to both the base station and the transponder. A maximum permissible time period is laid down, this being based on the assumption that the modulation of the transmitted power would have to be evaluated in the event of a redirecting process and that an additional time delay would thereby ensue between the transmission of the interrogation signal and the reception of the reply signal. If the time difference between the interrogation and the reply signals is greater than the redefined minimum time, then it is assumed that redirection has occurred and the authentication process is terminated.
[0007] The disadvantage of the previous methods is that redirection is not impeded or is not made difficult enough when using the previous methods. It is true that the reversible alteration of the frequency makes the frequency conversion process that is generally carried out during a redirecting process more difficult, but the degree of difficulty involved is determined only by the precision of the frequency conversion process within the redirecting device. Insofar as it is possible to effect a high precision conversion and re-conversion of the frequency in the redirecting devices, then an authentication process can be carried out and unauthorised access to a motor vehicle for example can be obtained. In the case of the other known method, which attempts to detect redirection by encoding the modulation of the transmitter power, this can already be done by the currently known devices (transceivers) that are used for redirecting purposes. Thus the known transceivers compensate for the additional attenuation losses, which are caused by the greater length of the signal path during the redirecting process, by subjecting the signals to linear amplification without thereby altering the relative modulation of the transmitter power. However, as the modulation of the transmitter power does not have to be decoded, the time loss postulated by the method does not occur and redirection cannot be detected. Neither of the two methods offers sufficient protection from unauthorised access within an authentication process.
SUMMARY OF THE INVENTION
[0008] Aspects of the present invention seek to provide a method which detects a redirection of the signals.
[0009] According to the present invention, there is provided a method of detecting a redirecting process in the course of a bi-directional non-contact making transmission of data between a first transmitting and receiving unit and a second transmitting and receiving unit wherein the first transmitting and receiving unit transmits an interrogation signal, the value of the amplitude (A 1 ) of the received interrogation signal is measured by the second transmitting and receiving unit, the measured value of the amplitude (A 1 ) is transmitted back in a reply signal, and the value of the amplitude (A 2 ) of the received reply signal is measured by the first transmitting and receiving unit and compared with the returned value of the amplitude (A 1 ).
[0010] In embodiments of the present invention, in the course of a bi-directional non-contact making transmission of data, it is determined as to whether a redirecting process is taking place by means of a comparison of the attenuation characteristics of the transmission paths between a first transmitting and receiving unit and a second transmitting and receiving unit. To this end, the interrogation signal transmitted by the first transmitting and receiving unit is measured in regard to the amplitude thereof in the second transmitting and receiving unit. The measured amplitude value is transmitted back to the first transmitting and receiving unit in a reply signal, preferably, in encoded form. Furthermore, the amplitude of the received reply signal is determined in the first transmitting and receiving unit and is compared with the returned value of the amplitude, whereafter a value is assigned to a redirection indicator in dependence upon the comparison. One can exclude the possibility that a redirecting process is occurring, if the result of the comparison of the amplitude values falls within a predefined interval.
[0011] Methods in accordance with the present invention are based upon the principle that in the case of a communication process not subjected to redirection, the transmission path will be symmetrical in regard to the attenuating behaviour thereof, i.e. both the forward path and the return path will have the same attenuation characteristics since the two transmitting and receiving units utilise a single respective antenna for the transmission and reception of signals. If the signals are prolonged by means of a redirecting device, then the redirecting device is utilising different antennae for transmitting and receiving purposes and is amplifying the signals in order to compensate for the additional attenuation caused by the redirecting device. Differing coupling factors between the antennae in the transmitting and receiving units and those in the redirecting device are associated with the different antennae used for transmitting and receiving purposes in the redirecting device, these differing coupling factors removing the symmetry of the transmission paths and heavily attenuating, in different manners, the amplitude of the interrogation signal in comparison with the amplitude of the reply signal.
[0012] In a further development of the method, the information regarding the attenuating characteristics of the signal path, which can be extrapolated from the measured value of the amplitude, is protected from unauthorised access. To this end, the digitalised value of the amplitude is inserted into the reply signal in encoded form. For an authentication process in which the authorisation is checked by examining encoded ID codes, the value of the amplitude could be coded using the same key as that with which the ID code of the respective transmitting and receiving unit was encoded prior to the transmission. By virtue of such an encoding process, it becomes impossible to evaluate the attenuation information using justifiable resources.
[0013] In another embodiment of the method, the comparison of the amplitudes is carried out within a predefined time window, whereby a check can be made as to whether the reply signal immediately follows the interrogation signal in time. Consequently, any change in position of either of the two transmitting and receiving units during the communication process between the first transmitting and receiving unit and the second transmitting and receiving unit will be prevented from removing the symmetry of the transmission path but a suspected redirecting process will be indicated by means of the resultant differing attenuations of the amplitudes. Furthermore, a redirecting device will be prevented from compensating for the asymmetry of the attenuation characteristics by trying to repeatedly change its signal amplification factor.
[0014] In another embodiment of the method, redirection is detected by comparing the frequency of the interrogation signal with the frequency of the reply signal, this being done in addition to the comparison of the amplitudes made by the first transmitting and receiving unit. In order to make the interval used for the frequency comparison as small as possible, it is advantageous if the second transmitting and receiving unit carries out a frequency coupling process with the frequency of the interrogation signal transmitted by the first transmitting and receiving unit. The carrier frequency can thereby be regenerated for the purposes of modulating the data in the reply signal. Since the frequency of the reply signal and that of the carrier signal are identical, the smallest deviations of the carrier frequency can be detected. A process of redirecting at the same frequency is thereby made extremely difficult since the functioning of the redirecting device will be adversely affected due to feedback. A frequency conversion process effected by the redirecting device within the redirection path leads to the carrier frequency being subjected to a frequency off-set. Should the result of the frequency comparison lie within the predefined interval, then it is possible to exclude the likelihood of a redirecting process.
[0015] In another embodiment of the method, the first transmitting and receiving unit also checks, in addition to the comparison made in respect of the amplitudes and the frequencies, as to whether the carrier signal remains uninterrupted, apart from field-gaps during the transmission of the interrogation signal, until the reception of the reply signal. Consequently, it is extremely difficult for a redirecting device to convert the carrier frequency for the purposes of redirecting the transmission without this being detected by the first transmitting and receiving unit. Amplification of the signals, which would compensate for the additional attenuation caused by the lengthening of the signal path, has to be effected at the frequency of the carrier by the redirecting device. In so doing however, the redirecting device can only compensate for the additional attenuation losses insofar as the signal amplification factor thereof remains smaller than the value of the decoupling between its transmitting and receiving antennae. On the other hand, if the circuit amplification factor within the redirecting device is greater than one, then this would result in feedback so that the functioning of the redirecting device would be extremely badly affected.
[0016] Experiments made by the applicant have shown that it is advantageous if a comparison of the amplitude values and a comparison of the frequencies is effected within an authentication process whilst checking the authorisation by means of an ID code. Thus, these methods do not require any additional time for detecting a redirecting process and can be employed, to advantage, for applications in the field of motor vehicles. Moreover, in applications in the motor vehicle field, the time span of 50-130 msec allowed for the authentication process is too short, except at intolerable expense, for decoding the amplitude values which are transmitted back with the reply signal, or, for compensating for the differing attenuation characteristics on the forward and return paths by means of some other method. Consequently, the possibility of unauthorised authentication by means of a redirecting process can be reliably excluded.
BRIEF DESCRIPTION OF THE FIGURES
[0017] Preferred embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, of which:
[0018] [0018]FIG. 1 shows an embodiment of the invention in the form of a method for determining the attenuation of the amplitudes in a bi-directional data transmission system involving a redirecting process;
[0019] [0019]FIG. 2 shows an embodiment of the invention in the form of a method for determining the attenuation of the amplitudes whilst simultaneously comparing the carrier frequencies when there is no redirection; and
[0020] [0020]FIG. 3 shows a flow diagram for the authentication process in conjunction with the embodiment illustrated in FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] The purpose of the embodiment depicted in FIG. 1 is to detect redirection or interception of data during an exchange of data between a first transmitting and receiving unit and a second transmitting and receiving unit by making a comparison between the attenuation of the amplitudes on the forward path and the return path. An arrangement of this type can be employed for authentication purposes in systems in the motor vehicle field for example, so as to detect a redirecting process. The system illustrated consists of a first sending and receiving unit RXTX 2 which will be referred to hereinafter as the base station, a second transmitting and receiving unit RXTX 1 which will be referred to hereinafter as the transponder. Moreover, there is also depicted a redirecting device WL which lengthens the communication paths between the base station RXTX 2 and the transponder RXTX 1 . The communication path from the base station to the transponder will be referred to as the UPLINK, whereas the reverse communication path will be referred to as the DOWNLINK. The construction of the individual devices will now be explained.
[0022] The base station RXTX 2 consists of an oscillator unit OSC 2 which produces a carrier frequency F 2 that is used for modulation purposes in an output amplifier TX 2 . Using the data delivered by a data processing unit DP 2 , the output amplifier TX 2 produces a modulated output signal F 2 OUT which is transmitted in the form of an interrogation signal having the power P 2 OUT by means of a transmitting and receiving antenna AN 2 . Furthermore, the transmitting and receiving antenna AN 2 is connected to an input amplifier RX 2 so as to amplify an incoming input signal F 2 IN having an input power P 2 IN and pass it on to a signal processor SP 2 . The signal processor SP 2 measures the magnitude of the amplitude of the input signal F 2 IN and passes the measured value A 2 to the data processing unit DP 2 . Furthermore, the signal processor SP 2 demodulates the input signal F 2 IN and passes on the data recovered from the carrier signal to the data processing unit DP 2 .
[0023] As regards the lengthening of the UPLINK communication path by the redirecting device WL, the interrogation signal transmitted by the base station RXTX 2 is passed on from a first receiving antenna E 1 to an amplifier RY 1 which then retransmits this interrogation signal that has been amplified by the factor G 1 by means of a first transmitting antenna S 1 . As regards the lengthening of the DOWNLINK communication path by the redirecting device WL, a reply signal transmitted by the transponder RXTX 1 is passed on from a second receiving antenna E 2 to a second amplifier RY 2 which then retransmits the reply signal that has been amplified by the factor G 2 from a second transmitting antenna S 2 .
[0024] The transponder RXTX 1 consists of an oscillator unit OSC 1 which produces a carrier frequency F 1 that is used for modulation purposes in an output amplifier TX 1 . Using the data delivered by a data processing unit DP 1 , the output amplifier TX 1 produces a modulated output signal F 1 OUT which is transmitted in the form of a reply signal having the transmission power P 1 OUT by means of a transmitting and receiving antenna AN 1 . Furthermore, the transmitting and receiving antenna AN 1 is connected to an input amplifier RX 1 so as to amplify an incoming input signal F 1 IN having a reception power P 1 IN and pass it on to a signal processor SP 1 . The signal processor SP 1 measures the magnitude of the amplitude of the input signal F 1 IN and passes on the measured value A 1 to the data processing unit DP 1 . Furthermore, the signal processor SP 1 demodulates the input signal F 1 IN and passes on the data derived from the carrier signal to the data processing unit DP 1 .
[0025] For the UPLINK, the magnitude of the attenuation between the base station RXTX 2 and the redirecting device WL is defined by a coupling factor K 21 , and the attenuation between the redirecting device and the transponder is defined by a coupling factor K 11 . In a corresponding manner for the DOWNLINK, the attenuation between the transponder RXTX 1 and the redirecting device WL is defined by a coupling factor K 12 , and the attenuation between the redirecting device WL and the base station RXTX 2 is defined by a coupling factor K 22 . Furthermore, the coupling between the antennae E 1 and S 2 is defined by a factor KRY 21 , and the coupling between the antennae S 1 and E 2 is defined by a factor KRY 12 .
[0026] The manner in which the arrangement functions will now be explained. In the UPLINK, the communication path is lengthened by the redirecting device WL, in that the redirecting device WL receives an interrogation signal transmitted by the base station RXTX 2 and, after amplification, retransmits it. The interrogation signal is demodulated by the transponder RXTX 1 and the measured value of the amplitude A 1 of the interrogation signal is retransmitted in the form of data in a reply signal for the DOWNLINK. Then, in the DOWNLINK, the communication path is lengthened by the redirecting device WL, in that the received reply signal is amplified and transmitted to the base station RXTX 2 . The base station RXTX 2 demodulates the received reply signal and compares the value of the amplitude A 1 that has been retransmitted with the reply signal with the measured value of the amplitude A 2 of the reply signal in the data processing unit DP 2 . If the two values of the measured amplitudes differ, then a digit 1 is stored in an internal memory by the data processing unit DP 2 , and an indication is given that redirection has occurred. If the result of the comparison falls within a predefined interval, then the digit zero is stored in the memory to show that it can be concluded that a redirecting process has not occurred.
[0027] In the case of a predefined transmitting power P 2 OUT and P 1 OUT and a predefined amplification of the input signals P 2 IN and P 1 IN by the base station RXTX 2 and the transponder RXTX 1 , the values A 1 and A 2 of the amplitudes of the interrogation signal and the reply signal are dependent on the coupling factors for the UPLINK and the DOWNLINK and upon the amplification factors G 1 and G 2 in the redirecting device WL. In the present example, the following relationship applies for a coupling factor KUL in the case of redirection in the UPLINK:
KUL=K 21 +G 1 +K 11
[0028] and a coupling factor KDL for the DOWNLINK is given by:
KDL=K 12 +G 2 +K 22
[0029] As a result of the asymmetry between the transmission paths in the UPLINK and the DOWNLINK, the two coupling factors KDL and KUL and the attenuation of the amplitudes A 1 and A 2 are different. In contrast thereto, the transmission path will exhibit a symmetrical attenuation characteristic if the redirecting device should be removed from the communication path. In this case, the following relationship exists for the two coupling factors KDL and KUL in the UPLINK and the DOWNLINK:
KDL=KUL
[0030] Furthermore, due to the additional coupling factors and the free space attenuation included therein, the attenuation of the amplitudes will be greater in the event of redirection than would be the case without redirection. Based on the difference in the attenuation characteristics when the redirecting device WL is present compared with the case when the redirecting device WL is absent, a reliable method of detecting redirection is obtained by the process of comparing the amplitudes A 1 and A 2 . This also applies in the case where the redirecting device WL attempts to compensate for the asymmetry of the attenuation characteristic by means of the amplification processes G 1 and G 2 since, without undue expenditure, this cannot be carried out without knowledge of the distances involved in the communication or knowledge of the coupling factors K 11 to K 22 . Insofar as the redirecting device WL effects amplification of the amplitudes A 1 and A 2 on the carrier frequency F 1 , the coupling factors KRY 12 and KRY 21 determine the maximum permissible degree of amplification G 1 and G 2 . In order to prevent oscillations occurring in the redirecting device WL due to feedback, the circuit amplification factor of the redirecting device must remain below 1.
[0031] In a further embodiment which is illustrated in FIG. 2, a comparison of the carrier frequencies of the interrogation signal and the reply signal is carried out in addition to the comparison of the amplitudes that has already been described with reference to FIG. 1 in the case of communication between the base station RXTX 2 and the transponder RXTX 1 . Accordingly, the functional construction of the base station RXTX 2 and the transponder RXTX 1 described hereinafter is identical, except for the aforesaid extension, with the functions illustrated in FIG. 1. Furthermore, in the embodiment illustrated, the communication between the base station RXTX 2 and the transponder RXTX 1 is effected without a redirecting process being involved, so that the coupling factor KUL for the UPLINK is identical to the coupling factor KDL for the DOWNLINK. A preferred utilisation of the embodiment within an authentication process will be explained in conjunction with the explanations given in connection with FIG. 3.
[0032] Within the base station RXTX 2 , the carrier signal F 2 produced by the oscillator OSC 2 is additionally supplied to a frequency comparison unit FC, the output of which is connected to the data processing unit DP 2 . Furthermore, the reply signal, which has been amplified by the receiving amplifier RX 2 and whose carrier has been regenerated by means of a unit CLK 2 , is supplied to the frequency comparison unit FC. The oscillator unit OSC 1 is replaced by a unit CLK 1 in the transponder RXTX 1 . The reply signal amplified by the input amplifier RX 1 is supplied to the unit CLK 1 for the purposes of regenerating the carrier. Following the regeneration process, the carrier is supplied at a frequency F 21 to the output amplifier TX 1 for a fresh modulation process whereafter it is transmitted.
[0033] The manner in which the arrangement functions will now be explained. At the beginning of the transmission of the interrogation signal, the unmodulated carrier signal F 2 is supplied to the frequency comparison unit FC. As soon as the transponder RXTX 1 receives the interrogation signal, an unmodulated carrier having the frequency F 21 is obtained by regenerating the carrier signal with the aid of the unit CLK 1 , and this is then supplied to the transmitting amplifier TX 1 for a fresh modulation process and retransmission to the base station RXTX 2 in the form of a reply signal. A rigid frequency coupling process is thereby carried out. As soon as the reply signal has been received in the base station RXTX 2 , the carrier having the frequency F 21 , which is derived from the reply signal by the unit CLK 2 , is supplied to the frequency comparison unit FC for the purposes of comparing the frequencies of the interrogation signal and the reply signal. Consequently the frequency F 2 of the oscillator unit OSC 2 and the frequency F 21 obtained from the reply signal are applied to the unit FC. The frequency comparison unit FC will supply a signal to the data processing unit DP 2 insofar as the two frequencies are equal. If the evaluation of the amplitudes that was carried out simultaneously by the data processing unit DP 2 also results in the two values of the amplitudes A 1 and A 2 being equal then one can exclude the possibility of a redirecting process.
[0034] The flow diagram for an authentication process based on the embodiment illustrated in FIG. 2 will be described in connection with FIG. 3.
[0035] Following the start of the authentication process, by actuating the door handle of a vehicle for example, the output amplifier TX 2 in the base station RXTX 2 transmits an interrogation signal SN 2 , which preferably incorporates encoded data, during a first process step TRANSMIT SN 2 . In a succeeding process step RECEIVE SN 2 , the interrogation signal is amplified by the input amplifier RX 1 in the transponder RXTX 1 and it is then passed on. Whilst the unit CLK 1 derives the carrier from the interrogation signal in a process step EXTRACT F 2 , the value of the amplitude A 1 is measured and the data is separated from the carrier within the signal processing unit SP 1 in the course of the process steps MEASURE AM 1 and EXTRACT DATA which run in parallel. In a following process step DECRYPT DATA, the data is decoded and is then checked for agreement with an internally stored code in a query step ID-CODE. If the ID code is not valid, the authentication process comes to an end and a reply signal will not be sent back. If the ID code is valid then the measured value of the amplitude A 1 is encoded in a following process step ENCRYPT, whereafter it is retransmitted in the form of a reply signal by the output amplifier TX 1 in the course of a succeeding process step TRANSMIT SN 1 . Following the reception of the reply signal in the base-station RXTX 2 , which is characterised by the process step RECEIVE SN 1 , the value of the amplitude A 2 is measured and the data is separated from the carrier within the signal processing unit SP 2 during the process steps MEASURE AM 2 and EXTRACT DATA which run in parallel simultaneously with a process step EXTRACT F 21 in which the unit CLK 2 regenerates the carrier for the frequency comparison process. In a succeeding process step DECRYPT DATA, the data is decoded and a check is made during a query step ID-CODE as to whether the retransmitted ID code matches an internally stored code. If the ID code is not valid, the authentication process comes to an end. If the ID code is valid, it is checked in the two succeeding query steps F? and A? as to whether the frequency F 2 matches the frequency F 21 and as to whether the ratio of the amplitudes A 1 and A 2 matches a predetermined value. If the result of one of these queries is negative then the authentication process comes to an end. If the result of both queries is positive, then the authentication process has been successfully completed i.e. the doors of the vehicle are unlocked in a succeeding process step UNLOCK.
[0036] It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations. | In a method of detecting redirection or interception during a bi-directional non-contact making data transmission, the attenuation (A 1 ) of the amplitude over the forward path is compared with the attenuation (A 2 ) of the amplitude over the return path. The attenuation (A 1 ) over the forward path is transmitted in encoded form with the reply signal. If the attenuation values determined thereby are of the same magnitude, then the likelihood of a redirecting process can be excluded. In order to additionally increase the security of the system, the carrier frequency (F 2 ) of the interrogation signal can also be compared with the carrier frequency (F 21 ) of the reply signal. The signals can also incorporate an ID code. | 29,065 |
BACKGROUND OF THE INVENTION
This invention relates generally to a method of cold on-column injection of a liquid sample onto a capillary gas chromatography column and more particularly to such a method that can be used with a relatively larger sample size without producing the peak distortion or splitting observed under conventional on-column injection conditions.
The two principal objectives of a sampling technique in capillary gas chromatography are to allow identical composition for sample injected onto the column and sample prior to the injection, and to introduce no or minimum extra column band broadening effects so that the total column resolving power is maintained. The former objective is easily achieved by the on-column injection technique because non-vaporizing ("cold") on-column injection, unlike conventional vaporizing injection techniques (split, splitless or direct), can deliver a sample into a capillary gas chromatography column with little effect on composition. The discriminative, adsorptive and thermal effects commonly observed with vaporizing injectors are largely absent, and excellent quantitative accuracy and precision are obtainable. Thus, on-column injection has been successfully applied to a number of difficult sampling problems. As to the latter of the aforementioned objectives, however, intolerable band boardening has been produced by the injection of a liquid sample into a capillary column due to the dynamic spreading of the liquid sample by the carrier gas over a significant length of the column inlet. As described by K. Grob, Jr. in J. Chromatogr., Vol. 213 (1981) at page 3, an on-column injection of a large sample size can result in chromatographic peak splitting due to the effect of the column being flooded by the liquid sample. This liquid sample flooding not only reduces the total available column resolving power and lifetime but also provides minimal use for qualitative and quantitative chromatographic information. The extent of this flooding along the length of the column depends upon the sample size, the column diameter, the carrier gas flow rate, the solvent physicochemical properties, and the column temperature (which affects the viscosity of the carrier gas and surface tension of the liquid sample). In general, a sample size in the range of 1-2 microliters can typically flood a column length of more than 50 cm. A larger sample size up to 10 microliters can easily flood several meters of the column inlet. Thus, this initial spreading of the liquid sample zone is one of the most serious constraints on the use of the method, resulting not only in a non-reproducible peak profile depending on the distribution of the solute molecules within the flooded sample zone but also an extensive peak broadening which is determined by the initial sample bandwidth.
One of the attempts to reduce the effect of liquid sample flooding described by K. Grob, Jr. et al in J. Chromatogr., Vol. 244 (1982) at page 185 has been by removing the stationary phase on the first few meters of the column to prevent retention trapping of the non-uniformly distributed solute molecules. After injection, the flooded column inlet zone is heated up to vaporize sample molecules to be carried downstream to the column zone where stationary liquid traps solute molecules in a narrow initial sample zone. The technique improves the peak shape over that obtained with a conventional on-column injector. This technique, however, has limited success in practical applications due to the following drawbacks. Firstly, it is difficult in practice to strip stationary phase from a column inlet. In particular, nonpolar phases and chemically bonded phases are not completely removable. The use of an uncoated precolumn may allow satisfactory surface characteristics for the requirement of utilizing the retention gap technique, but the practical difficulties and constraints in column connection techniques have to be taken into consideration. Secondly, the retention gap technique does not solve the fundamental problem of sample size limitation. The amount of sample injected is again limited by the length of the retention gap. A sample size of 3 microliters may require 2-3 meters of retention gap to allow satisfactory peak shape. Thirdly, uncoated bare column walls for the retention gap may produce undesirable adsorption effects. Deactivation of the precolumn may not give satisfactory results due to the possibility of retention of solute molecules on the deactivated phase or phases, defeating the retention gap effect. Fourthly, the technique requires that the column oven temperature be cooled down to below the solvent boiling point before every injection. This could require more time than that required for a chromatographic separation. The speed of analysis is thus constrained by the injection technique.
It is therefore an object of this invention to provide a solute focusing method of introducing a liquid sample into a gas chromatographic column.
It is another object of this invention to provide an on-column injection method in gas chromatography which can yield chromatograms of good quality with relatively large sample sizes without causing intolerable peak shape distortion and, hence, useless chromatographic information.
SUMMARY OF THE INVENTION
The above and other objectives are achieved by applying solute focusing techniques to the on-column injection. The injection zone, or the inlet end of the chromatographic column, is kept at a temperature below the boiling point of the solvent while the adjacent downstream zone is kept at a higher temperature so that the following characteristics for an ideal on-column injection process can be achieved: (1) to allow liquid sample injection; (2) to vaporize and separate solvent from solute molecules quickly after injection; (3) to apply solute focusing technique to minimize initial solute molecular zone spreading; and (4) to allow separately temperature programmed injection and vaporization zones to obtain optimum resolution and speed of analysis.
BRIEF DESCRIPTION OF DRAWINGS
FIGS. 1(a) and 1(b) show schematically the principle of solute focusing technique which is applied to on-column injection according to the present invention.
FIG. 2 is a portion of the experimental results according to the method of the present invention, showing the effects of increasing sample size on peak shape.
FIG. 3 is a result of comparison experiment without solute focusing, showing the effects of increasing sample size on peak shape.
DETAILED DESCRIPTION OF THE INVENTION
The solute focusing technique of the present invention can be practiced, for example, by using the on-column gas chromatographic injector disclosed by P. L. Feinstein in U.S. patent application Ser. No. 342,958, filed Jan. 26, 1982 and assigned to the present assignee. The principle of the method is shown schematically in FIGS. 1(a) and (b). For the sake of simplicity, FIG. 1 illustrates a situation where the liquid sample introduced into a column 11 from a needle 12 consists of only one kind each of solute and solvent molecules (illustrated by shaded and open circles, respectively). An inlet portion 15, to be identified as injection zone, of the column 11 is surrounded by a temperature controlling means 25 including, for example, an electric heater and a cryogenic cooler for regulating the temperature of the injection zone 15. The zone inside the column 11 adjacent to and downstream from the injection zone 15 is identified as the vaporization zone 16 and is surrounded by a second temperature controlling means (column oven) 26 which controls the temperature of the vaporization zone 16. Thus, it is possible to control the injector and oven temperatures independently of each other and to select a variety of different combinations of these temperatures.
In operation, the sample is injected as shown in FIG. 1(a) in its liquid state. For solute focusing, the injection zone 15 is held at a temperature 20° to 40° C. below the solvent boiling point during injection, while the vaporization zone 16 is heated at 10° to 20° C. above the solvent boiling point. During injection, the relatively cold injection zone 15 becomes flooded to some degree with liquid sample. As the liquid is moved downstream by carrier flow and enters the hot vaporization zone 16, the solvent evaporates rapidly, and is carried away by the mobile phase, leaving the solutes trapped in a narrow stationary liquid band at the front of the vaporization zone 16 (FIG. 1(b)). Molecules which may flow back from the vaporization zone 16 will recondense in the injection zone 15 maintained at a low injection zone temperature in the meantime.
Immediately after the introduction of liquid sample is completed, the injection zone temperature is quickly increased to a level significantly higher than the solvent boiling point. This has the effect of driving any residual sample into the vaporization zone 16 where solute molecules are trapped, focused to a very narrow injection sample bandwidth.
After the injection zone 15 reaches this final temperature, normal oven temperature programming is started so that on-column injection can be carried out under the correct non-vaporizing conditions, while flooding of a large column section is avoided. Stripping of the inlet section is not required since band sharpening is achieved by a combination of thermal focusing and retentive focusing (cold trapping). Vapor backflow during injection into the cooled injection zone 15 is not a concern since the entire area is heated after injection.
Experimentally observed effects of increasing sample size on the chromatograph peak shape are shown in Table I below both with and without solute focusing. In these experiments, the sample was an n-alkane mixture in isooctane (boiling at 98° C.). With solute focusing the injection zone temperature was raised from 20° C. to 300° C. at the rate of 180° C./min while the vaporization zone temperature was initially kept at 110° C. for one minute and then raised to 300° C. at the rate of 10° C./min. Without solute focusing, the injection and vaporization zone temperatures were the same and were held for one minute initially at 80° C. and then raised to 300° C. at the rate of 10° C./min. FIG. 2 shows chromatograms obtained with solute focusing under these conditions. In contrast to the results without solute focusing, (FIG. 3), these chromatograms for sample sizes of 1 to 8 microliters show excellent peak shape and nearly constant peak widths from 1- up to 8-microliter injection sizes. Table I lists the experimentally determined peak widths at half height for several peaks from the chromatograms obtained both with and without solute focusing.
TABLE I______________________________________InjectedAmount With Solute Without(Microliter) Solute Focusing Solute Focusing______________________________________1.0 n-C26 3.1 3.5 n-C30 3.0 5.5 n-C44 2.6 5.45.0 n-C26 3.2 14.4 n-C30 3.0 17.1 n-C44 3.8 18.28.0 n-C26 3.2 21.7 n-C30 3.1 22.9 n-C44 4.0 26.7______________________________________
The present invention has been described above only in terms of the general method and one set of experiments. The above description, however, is to be considered as illustrative rather than as limiting, and this invention is accordingly to be broadly construed. For example, FIG. 1 is to be interpreted merely as a schematic illustration so that the depicted dimensional relationships are not intended to be realistic. The length of the injection zone, however, is normally between 10 and 15 cm which can have stationary phase either present or stripped.
The injection and vaporization zone temperatures can also be adjusted conveniently although the vaporization zone temperature should usually be more than 10° C. higher than the solvent boiling point at 1 bar. This initial vaporization zone temperature in a constant flow pneumatics system may be determined by and optimized for the chromatographic resolution and speed of analysis. It can be above solvent boiling point by more than 10° to 15° C. to allow faster analysis time if the solute components of interest can be satisfactorily separated. In a constant pressure pneumatics, however, the applicable initial vaporization zone temperature is limited to about 10° to 15° C. above the solvent boiling point. This is due to the fact that a high vaporization zone temperature could produce rapid vaporization and pressure increase inside the column which could force liquid sample backflow into the injector and result in sample loss and peak shape distortion. A constant pressure pneumatics has also a limited applicable sample size due to the combined gas pressure of the carrier gas, and the vaporized sample inside the column may exceed the pressure at the injection zone during injection process. The proposed solute focusing technique performs best in a constant flow pneumatics system with a gas leak-tight on-column injector. A slow on-column injection of large sample size in a constant flow pneumatics systems prevents backflow of the vaporized sample inside the column because of a constant flow of carrier gas into the column maintained by the constant flow controller. The scope of the invention is defined only by the following claims. | A solute focusing method is applied to the on-column injection of a liquid sample in gas chromatography so that relatively large sample sizes can be used without causing intolerable column flooding. The injection zone of the column is kept originally at a temperature below the solvent boiling point but the temperature in the adjacent downstream zone is kept higher than the solvent boiling point so that the solvent will evaporate and flow downstream, leaving the solute molecules concentrated within a relatively limited length along the column. | 13,652 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to U.S. Provisional Patent Application No. 61/867,273 filed Aug. 19, 2013, which is incorporated herein to the extent not inconsistent herewith.
BACKGROUND
[0002] The brown recluse spider, Loxosceles recluse (Araneae: Sicariidae), is a common household pest in the Midwestern United States. It is mainly nocturnal and is capable of inflicting a venomous bite. Its coloration ranges from light to dark brown with markings on the dorsal side of the cephalothorax. L. recluse spiders have six eyes arranged in three pairs. They average about three-eighths of an inch in size.
[0003] Spider traps are known to the art, for example as described in U.S. Pat. Nos. 4,048,747, 4,052,811, 4,244,134, 4,324,062, 4,608,774, 4,819,371, 5,513,465, 5,572,825, 5,649,385, 6,786,001 8,341,873, US Patent Publication Nos. 20050138858 and 20050279016, EP Patent Publication No. EP2347759, and PCT Publication No. WO 9615664. Traps containing bait comprising double-stranded RNA for controlling brown recluse spiders are mentioned in EP Patent No. EP0659339, and described as box-shaped and made of a material such as corrugated cardboard with a sticky substance coating the material. At least one Loxosceles species prefers refuges that offer acute angles (Stropa 2010).
[0004] Glue-traps have been sold commercially for capture of not only arachnids but also flying insects, rodents, and reptiles. Glue-traps have also been used for estimating the population of beetle infestations (e.g., Hagstrum et al. 1994). In addition, glue-traps have been used to estimate brown recluse populations inside residential housing (Vetter et al. 2002). A search of the existing literature reveals no studies that compare spider trap designs, even though spider populations have been successfully estimated with glue-traps (Sandidge et al. 2005). Many such traps comprise behavior-altering chemicals such as pesticides and chemical attractants. Homeowners, however, are often deterred from using chemical pesticides due to possible health risks and environmental side effects.
[0005] Many insects are attracted to light, and traps for such insects utilizing light or food or other chemical attractants as bait have been described. However, brown recluse spiders prefer dark places, and many homeowners prefer not to attract human attention to such traps by using light.
[0006] There is a particular need for safe and consistent management for the brown recluse spider, Loxosceles reclusa Gertsch & Mulaik, a venomous spider found in large areas of central, eastern, and southern United States, and considered abundant in Kansas (Sandidge and Hopwood, 2005). This spider is a synanthrope and therefore is commonly found in association with human structures (Schenone et al., 1970). The brown recluse spider is venomous and, although bites are uncommon, when they do occur the bite may develop into a necrotic lesion where tissues around the bite break down, creating a slow-healing wound that may leave significant scarring (Anderson, 1982). Therefore, tolerance for brown recluse spiders in homes is very low and homeowners expect 100% control.
[0007] It is estimated that most homes in the area of brown recluse distribution are infested by these spiders, and that they are regularly transported to new homes in building materials or in items moved from other structures (Zurek, 2005). L. recluse has adapted so well to human dwellings that populations can be quite large with one report documenting up to 2,055 brown recluse spiders collected from a 270 m 2 Kansas home in a mere six-month time period (Vetter and Barger, 2002).
[0008] The brown recluse presents challenges for pest control professionals because it is so difficult to eliminate from structures. There have been few studies conducted to test the efficacy of modern pesticides and treatment methods for brown recluse spider control and the studies that have been conducted often report inconsistent results (Sandidge and Hopwood, 2005). One of the reasons that L. reclusa is so difficult to eliminate from structures is because of their secretive nature. These spiders are nocturnal, webs are typically built in out-of-the-way areas that are rarely disturbed, including difficult to access areas; locations of spiders will differ with each infestation depending on many variables including the layout of the home, temperature and population size (Sandidge and Hopwood, 2005). Additionally, L. reclusa is known to feed on a wide range of insect and other arthropod prey and has been shown to readily feed on dead prey, including freshly killed, dead several months, and even prey killed with insecticides (Sandidge, 2003). They can also survive a long time without food or water. Brown recluse spiders have been shown to live up to ten months in a controlled setting with no food or water and up to six months with no food, water, or fresh air (Sandidge and Hopwood, 2005). In addition, these spiders are long-lived, with an average lifespan of 646 days for males and 794 days for females, under favorable conditions (Elzinga, 1977).
[0009] Attempted management of these spiders has included the use of various fumigants and aerosols, many having no data to show they were effective, and which were often applied haphazardly and excessively. Early pesticide trials were contradictory and a number of the chemicals considered somewhat effective or effective are now restricted or banned in the United States (Norment and Pate, 1968; Gladney and Dawkins1972). For example, Hite et al. (1966) examined the efficacy of 13 topically applied chemicals, including lindane, diazinon, chlordane, malathion, and carbaryl. Of these tested chemicals only lindane, which has since been banned in the U.S., provided significant residual control of the spiders.
[0010] There is a need in the art for a trap for spiders and insects, and especially for the dangerous brown recluse spider, that does not use light as an attractant. There is also a need for such traps not containing chemical attractants or other chemical control substances. Because the brown recluse spider is an important arthropod pest in structures, good, safe, consistent control measures are needed in the form of improved methods for controlling their populations in indoor spaces.
[0011] All publications referred to herein are incorporated by reference for purposes of written description and enablement.
SUMMARY
[0012] A trap for spiders and other insects is provided herein that is especially useful for catching brown recluse ( Loxosceles reclusa ) spiders. In embodiments the trap does not comprise chemical attractants or other behavior-modifying environmentally harmful chemicals. In embodiments the trap does not comprise food bait. In embodiments, the trap does not use light to attract spiders or other insects.
[0013] In embodiments, the internal volume of the trap is shaped as a triangular prism as shown in FIG. 1 hereof, except that the triangular faces (sides) are open, i.e., are not solid faces. In embodiments, the triangular faces (sides) are solid, or one or more faces are solid with openings, therein, e.g., comprised of separate vertical struts. In other embodiments the trap is shaped as a pyramid. In other embodiments, the trap is shaped as a box. In embodiments at least one face of the spider trap is completely open. In embodiments, the front of the spider trap comprises openings and can be substantially open. In embodiments, one or more side walls of the trap extend beyond the shape formed by the internal volume of the trap. In embodiments the trap comprises at least one flat, planar wall or portion of a wall. In embodiments the trap comprises two parallel flat planar walls or portions of walls.
[0014] The spider trap comprises a floor, which in embodiments is rectangular, but can be any other shape. The floor, in embodiments, is disposed horizontally on the floor of a room or on a table or other object. The floor can be completely planar, or be wavy, stepped, or have any other regular or irregular surface features. In embodiments, the floor, back and front of the spider trap are all rectangular in shape.
[0015] The spider trap also comprises a back disposed at an angle θ to the floor. In embodiments angle θ is between about 80° and about 100°. The angle should be large enough, at least one inch, to accommodate the height of a typical spider, but no greater than about 100° so as to be able to place to trap flush against a vertical surface, such as a wall, cabinet, etc. In an embodiment the angle between the bottom of the back and the back edge of the floor is about 90°.
[0016] The spider trap also comprises a front disposed at an angle φ to the floor and an angle α to the back. The angle φ between the front and the floor should be large enough to allow spiders entry and small enough to keep dimensions on a compact size and in embodiments is between about 35° and about 55°. If the front is comprised of struts as shown in FIGS. 3 and 4 , each strut is desirably at said angle φ to the floor. If the front additionally comprises a horizontal bar at the bottom of the struts as shown in FIG. 4 , between the bottom of the struts and the front edge of the floor, the angle φ of the front with the floor is considered to be the angle of a notional line extending from the bottom of the horizontal bar to the front edge of the floor with the floor. The angle α between the top of the back and the top of the front should be between about 35° and about 55°. It should not be so large that compact trap size is adversely affected or so small that spiders are unable to gain entry. In embodiments, the front of the trap comprises one or more openings. In embodiments, the front of the trap is substantially open. The purpose of the opening(s) is to allow the spider to enter the trap from either the front or the sides of the trap. All walls of the trap can comprise openings sized and shaped so as to permit entry to spiders from any direction from which the spider approaches. The openings can be rectangular in shape, circular, arc-shaped, or any other regular or irregular shape desired.
[0017] At least a portion of the floor is covered with a bug adhesive capable of sticking to a spider leg as well as other body parts and is capable of substantially preventing disengagement of the spider therefrom. Bug adhesives such as those used in flypaper are well-known to the art and commercially available, e.g., available from Atlantic Glue and Paste and Glue, Brooklyn, N.Y., ISCA Technologies, Riverside, Calif., and Ningbo Yinzhou Hopson Chemical Industry Co. Ltd., Ningbo, China. The adhesive should retain its adherence properties for at least 3 months; it should be nontoxic to mammals, both pets and people; the MSDS (material safety data sheet) should be supplied with the adhesive and confirm lack of toxicity; and the adhesive should hold a spider fast after contact with any part of the spider.
[0018] The inventors have found that no spiders were caught on the vertical portions of commercial traps. Thus, while it does not appear to interfere with the effectiveness of the trap to provide bug adhesive on portions of the trap other than the floor, this is not necessary, and it is advantageous in terms of cost savings and ease of handling of the traps that bug adhesive not be coated on surfaces other than the floor of the trap.
[0019] Adhesive-coated surfaces of the trap can be covered with slick, peel-off paper for shipping and handling.
[0020] In an embodiment hereof, the inside of the trap is high enough to allow an adult Loxosceles reclusa with a leg span of up to 2.5 inches to walk inside if it is walking vertically along the wall and entering into the back of the trap without lowering itself in height to avoid touching the trap, and spacious enough to capture up to one dozen adult spiders. In embodiments, such traps hereof have a compact size, i.e., an internal volume between about 35 and about 50 cubic inches, and a height of at least about 2.5 inches.
[0021] In an embodiment hereof, the area of the trap floor is large enough to catch multiple spiders if spiders are not removed from the trap. In embodiments, traps hereof have a floor area between about 10 and about 24 square inches.
[0022] In embodiments such as that shown in FIG. 3 hereof, the traps have a front wall comprised of vertical struts, the struts have a width between about 0.15 and about 0.35 inches, wide enough to provide sufficient load-bearing capacity to support the front and back walls under normal use, but not so wide as to interfere with the spider's ability to enter the glue trap from the front of the trap between the struts.
[0023] In embodiments such as that shown in FIG. 4 hereof, the front of the trap has a horizontal bar wide enough to provide sufficient load-bearing capacity to support the front and back walls under normal use, e.g., between about 0.15 and about 0.35 inches.
[0024] In embodiments the walls and floor of the trap are fixedly attached to each other; in embodiments they are rotatably attached to each other so as to rotate through an angle of between about 40° and about 50°, and/or the walls can be removably attached to each other, such as by hinges, by a cord such as a cloth or plastic lacing, or by other fastening devices known to the art. They can also be rotatably connected to each other by being made of a flexible material capable of being folded to form a three-dimensional trap structure or portion thereof. In embodiments each wall of the trap is attached to another portion of the trap so as to form a single flat sheet that can be folded to make the three-dimensional trap. In embodiments. In embodiments, adjacent walls need not be fastened to each other if forces of friction or gravity or the buttressing forces of other walls or the floor will keep them in place during use, for example, in embodiments it may not be necessary to secure the front of the trap to the floor.
[0025] In embodiments, the spider trap is made from a material that is, or is made from, wood or wood products, e.g., natural wood, cardboard, including corrugated cardboard, paper, and/or chipboard. In embodiments at least some portions of the surfaces of the trap: the back and the struts are rough to provide a surface the spider can easily walk on.
[0026] Kits comprising trap components such as solid walls, fasteners, bug adhesive and instructions for their assembly are also provided herein. In embodiments, the trap is provided to consumers as a single foldable piece of material such as paper comprising tabs and slots, adhesive tabs or other attachment features known to the art for ease of assembly. Consumers can thus determine if they want an “open” (flat) trap or if they want to fold it over to prevent children and pets from contact with the bug adhesive, and manufacturers of the traps need only provide a single embodiment to serve both purposes.
[0027] In an embodiment, the trap is packaged for sale on a packaging board in the form of a single sheet as shown in FIG. 7 . The trap comprises a back section, a floor section, a front section and a fold-over tab section. Bug adhesive is coated on the floor section of the trap and covered with peel-off paper. A contact adhesive is coated on the fold-over tab and covered with peel-off paper.
[0028] A method for making a spider trap having the shape of a triangular prism comprises: providing a floor having front and back edges; coating or partially coating the floor with a bug adhesive capable of sticking to a spider leg; providing a back having a top edge and a bottom edge, sized and shaped so as to be capable of being fastened to the back edge of the floor; fastening the bottom edge of the back to the back edge of the floor such that the back is disposed at an angle θ to the floor; providing a front having a top edge and a bottom edge, the front being sized and shaped to be attached to the top edge of the back; wherein the front comprises openings defined by a series of vertical struts, a series of vertical struts in combination with a horizontal strut disposed along the bottom of the struts, or a solid portion having an “X” or hourglass shape; fastening the top edge of the front to the front edge of the back so that the front forms an angle α with the back; and optionally fastening the bottom edge of the front to the front edge of the floor so that the front forms an angle φ with the floor.
[0029] A suitable adhesive can be coated on the floor or portions thereof, and/or other walls of the trap before or after the walls are attached to each other.
[0030] Embodiments of the traps hereof having internal volumes with other shapes can be made by methods analogous to those described above.
[0031] To use the single-sheet trap, the back section of the trap is folded over toward the center of the trap to form a vertical back, leaving the rest of the trap flat. The front section the trap is folded upward and inward toward the center to form the front of the trap, leaving the floor section flat. The tops of the front and back are brought together. The contact paper is removed from the fold-over tab on the front of the trap and the fold-over tab is folded downward and inward to stick to the outside top edge of the back.
[0032] In use, the trap is disposed in an area believed to be a brown recluse spider habitat and allowed to remain there until one or more brown recluse spiders have become stuck to the adhesive coating. To determine whether an area is likely to be a brown recluse spider habitat, the following factors need to be considered:
a. Usual geographical habitat: areas of the United States: from southeastern Nebraska through southern Iowa. Illinois, and Indiana to southwestern Ohio. In the southern states, it is native from central Texas to western Georgia and north to Kentucky; b. Preferred surfaces: cardboard, newspaper, lumber; and c. Local habitat: dark, undisturbed places such as shoes, inside dressers, in bed sheets of infrequently-used beds, in clothes stacked or piled or left lying on the floor, inside work gloves, behind baseboards and pictures, in toilets, and near sources of warmth when ambient temperatures are lower than usual; and nearby areas where they can wander in search of mates and prey items.
[0036] It is not necessary to bait the trap with food or other attractants.
[0037] Spider traps hereof made of biodegradable, non-toxic materials, along with spiders that have been trapped therein, can be left in place in wilderness settings or in urban and household environments can be disposed of with other biodegradable waste.
[0038] This disclosure also provides methods for controlling brown recluse spider populations in indoor spaces utilizing spider traps.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] FIG. 1 shows a side view of the spider traps hereof.
[0040] FIG. 2 shows a perspective view of a spider trap hereof having an X-shaped strut design.
[0041] FIG. 3 shows a perspective view of a spider trap hereof having a vertical strut design.
[0042] FIG. 4 shows a perspective view of a spider trap hereof having a vertical strut design with a horizontal bar at the bottom.
[0043] FIG. 5 shows a perspective view of a flat trap design.
[0044] FIG. 6 shows a perspective view of a prior art box trap design used as a control for evaluating the traps hereof.
[0045] FIG. 7 illustrates a commercial version of the trap that can be packaged and sold in flat form and folded by the customer to a three-dimensional conformation.
DETAILED DESCRIPTION
Definitions
[0046] A prism is a shape made of two parallel faces that are polygons of the same shape and sides that are parallelograms.
[0047] A triangular prism is a prism with triangular faces, e.g., as shown in FIG. 1 .
[0048] A pyramid is a shape with a base that is a polygon and triangular sides.
[0049] The term “rectangular” as used herein includes square.
[0050] The term “vertical” as used herein with respect to trap walls means extending in an upward direction from the floor at any angle.
[0051] The term “back” as used herein with respect to the traps hereof refers to a wall having the least number of openings of any other wall of the trap.
[0052] The term “front” as used with respect to the traps hereof refers to a vertical wall which is approximately or directly opposite to the back wall if the trap has four or more faces, or if the trap has three faces, it can refer to either adjacent wall.
[0053] The term “floor” as used with respect to the traps hereof refers to a horizontal portion of the bottom of the trap.
[0054] The term “top” “bottom,” “upward,” “downward,” “above” and “below” are used herein in their usual meaning relative to the force of gravity when a trap is placed with its floor perpendicular to the force of gravity.
[0055] The term “side” as used with respect to the traps hereof refers to any face of the internal volume of the trap that is not a front, back or floor.
[0056] The term “open” as used with respect to a face of the trap means that there is no wall on that face.
[0057] “Substantially open” as used herein with respect to the front of the trap means that solid portions of the front of the trap are disposed so as to be directly over no more than about 50% to about 75% of the area of the floor.
[0058] The “internal volume” of the trap is the three-dimensional shape enclosed by the walls of the trap, and if one or more sides are “open,” that is, are without walls, the internal volume of the trap is defined by the edges of the walls adjoining the “open” walls.
[0059] The term “substantially preventing disengagement of a spider leg” as used with respect to the capability of bug adhesives used herein means that in at least about 75% of cases in which a brown recluse spider's leg is stuck to the adhesive, the spider will not be able to pull the leg free.
[0060] The brown recluse spider, L. reclusa , is sometimes referred to as the violin or fiddleback spider because of the violin-shaped marking on its dorsum. Although bites are rare, the venom can cause serious wounds and infestations should be taken seriously. The brown recluse spider is most common in the south and central states of the United States, especially in Missouri, Kansas, Arkansas, Louisiana, eastern Texas, and Oklahoma. However, the spider has been found in several large cities outside this range.
[0061] Brown recluse ( L. reclusa ) spiders prefer dry, dark, undisturbed places, although they do wander in search of mates and prey items. Although reclusive and shy, they have shown a preference for certain surfaces, such as cardboard, newspaper, and lumber, and other Loxosceles species have shown similar preferences (Fischer et al. 2005). Of these choices, cardboard was used in the Example hereof as the most practical and most inexpensive choice for trap construction.
[0062] While there are limited options for chemical-free arachnid pest control, glue-traps are one suitable alternative to pesticides. Four novel trap shape designs and one popular glue trap already on the market were tested to determine if one (or more) of the new designs were more likely to catch brown recluse spiders than the existing design. Although this type of trap was most efficient for capturing L. reclusa , it can pose risks in homes with children and pets for obvious reasons. Among the traps with coverings, the vertical strut trap was most preferred by the spiders, and recommended for homeowners with children and pets.
[0063] In the specific embodiments depicted in the Figures, it is to be understood that the specific dimensions and relative dimensions of the traps are not essential features of the traps. The specific and relative dimensions can be feely varied to form a wide range of embodiments within the general parameters specified herein.
[0064] In embodiments, a kit for making a trap for spiders and other insects is provided comprising the following components: a flat sheet of a foldable wood product comprising: a back section optionally comprising a slit; a floor section integral with said back section at least partially coated with bug adhesive covered with peel-off paper; a front section integral with said floor section, said floor section comprising openings therein; a tab section integral with said front section sized and shaped, in use, to be folded over the top of the back section, said tab section optionally comprising at least a partial coating of contact adhesive covered with peel-off paper; or said tab section optionally being sized and shaped so as, in use, to fit into said slit in said back section; and instructions for configuring said flat sheet into a three-dimensional spider trap.
[0065] A method of making the kit is also comprising: providing a flat sheet comprising front, floor, back and tab sections; coating at least a portion of said floor section with bug adhesive; covering at least said coated floor section with peel-off paper; optionally coating said tab section with contact adhesive and covering said coated tab section with peel-off paper; preparing instructions for peeling off said peel-off paper and folding said flat sheet into a three-dimensional spider trap, wherein said instructions are printed on said flat sheet or provided separately; and packaging said flat sheet and instructions for sale.
[0066] A method for making a three-dimensional spider trap from such a kit is also provided comprising: removing said peel-off paper from said bug adhesive on said floor section; folding said back section upward and inward with respect to said floor section to form the trap back; folding said front section upward and inward with respect to said floor section to form the trap front; folding said tab section inward and downward with respect to said trap front to fold over the top of said trap back; and securing said tab to the top of said trap back by: inserting it into said optional slit on the trap back; or peeling said optional contact adhesive from said tab and sticking said tab to the top of the back edge of said front.
[0067] Further provided herein is a method for catching a brown recluse spider comprising: Identifying a location where brown recluse spiders are likely to be living; disposing a trap of claim 1 in said area; and allowing said trap to remain in said area until one or more spiders have become stuck to the bug adhesive coating on said trap. To determine whether brown recluse spiders are likely to be living in an area, the following factors should be considered: the area should be defined as the approximate area a brown recluse spider will typically roam over; whether or not a brown recluse spider has been spotted in the area; whether a bite suspected of being a brown recluse spider bite has been experienced by a person in the area; whether the area is located in a geographical region known to be a brown recluse spider habitat; whether the area is an area where humans are likely to go; whether the area provides wood-derived materials as likely brown recluse spider habitats; whether the area provides piles of clothing or rubble likely to provide suitable habitats for brown recluse spiders, and other factors known to the art.
[0068] The traps can be left in the area until brown recluse spiders have been captured, or if no spiders are captured within a period of about 14 days, it can be assumed the area is not a significant brown recluse spider habitat.
[0069] The traps hereof can also be used to estimate the brown recluse spider population in an area by placing them in an area and counting the number of spiders caught therein over a selected period of time.
[0070] FIG. 1 shows a generalized side view of spider traps 10 hereof shown in FIGS. 2-4 . In the embodiment shown in FIG. 1 , back 12 has a height of 6.83 inches. Floor 16 has a width of 6.99 inches. Sides 14 can be present as solid walls, or can be completely or partially open or absent. They are triangular in shape and have a height of 6.83 and a width of 6.99 inches. The angle α between back 12 and front 18 , and the angle φ between floor 16 and front 18 in the embodiment illustrated are about 45°, and the angle θ between floor 16 and back 12 is about 90°. Front 18 lies on a plane extending from the top of back 12 to the front of floor 16 .
[0071] FIGS. 2-4 depict traps hereof in which fronts 18 comprise openings of varying shapes and sizes. The solid portions of front 18 can be formed as a single piece or made from separate pieces attached to each other. Sides 14 are open rather than being walls in the embodiments depicted in FIGS. 2-4 .
[0072] FIG. 2 shows a perspective view of spider trap 10 hereof having an X-shaped or hourglass strut design. The hourglass design is one embodiment of the X-shaped design that includes narrow vertical struts 25 along each vertical edge of front 18 . The X-shaped design can include vertical struts 24 , or such vertical struts can be absent. In the embodiment depicted, back 12 has a height of 6.67 inches, a length of 13.49 inches and a width of 6.99 inches. Front 18 , which is rectangular in shape, has a length of 13.49 inches and a width of 9.53 inches. Floor 16 , coated with a bug adhesive 28 , is visible in this view. Solid portion 22 of front 18 comprises triangular openings 20 bounded by solid portions 22 . In the embodiment shown, the solid portions forming the “X” have a width of 0.795 inches and are connected to or integral with narrow vertical struts 25 .
[0073] FIG. 3 shows a perspective view of spider trap 10 hereof having a vertical strut design. Floor 16 , coated with bug adhesive 28 (shown as dotted lines) is visible in this view. Vertical openings 20 a are defined by the solid portion of front 18 which is composed of separate full-length vertical struts 24 . In the embodiment shown, back 12 has a height of 6.67 inches and a length of 13.49 inches. Floor 16 has a width of 6.99 inches and a length of 13.49 inches. In the embodiment shown, two narrow vertical struts 25 are disposed at the left and right ends of trap 10 , and three wider vertical struts 24 are evenly spaced between them, defining vertical openings 20 a . The vertical struts 24 depicted have a length of 8.26 inches and a width of 0.25 inches and extend from the top of back 12 to the front of floor 16 .
[0074] FIG. 4 shows a perspective view of spider trap 10 hereof in which front 18 comprises partial-length vertical struts 24 a , connected at their lower ends to horizontal bar 26 . Floor 16 , coated with bug adhesive 28 is visible in this view. Partial-length vertical struts 24 a define vertical openings 20 a . Horizontal bar 26 is disposed along the bottom of vertical slates 24 a , and spaced apart from the front edge of floor 16 so as to define horizontal opening 20 b . In the embodiment shown, back 12 has a height of 6.66 inches and a width of 13.49 inches. Floor 16 has a width of 6.99 inches and a length of 13.49 inches. Front 18 has a length of 13.49 inches and a width of 9.53 inches. Horizontal bar 26 has a width of 0.795 inches and horizontal opening 20 b has a width (vertical height) of 2.54 inches.
[0075] FIG. 5 shows a perspective view of a prior art Catchmaster™ flat trap design comprising a flat, rectangular substrate 30 on which bug adhesive 28 is coated. In the embodiment shown, substrate 30 has a length of 13.49 inches and a width of 6.99 inches.
[0076] FIG. 6 shows a perspective view of a prior art Catchmaster™ box trap design used as a control for evaluating the trap designs depicted in FIGS. 2-4 . In the embodiment shown, the back of the trap has a height of 3.49 inches, a length of 13.34 inches. The front of the trap has a height of 2.54 inches and a length of 13.54 inches.
[0077] FIG. 7 illustrates a commercial version of trap 10 hereof that can be packaged and sold in the form of a flat sheet and folded by the customer into a three-dimensional conformation along the horizontal lines depicted between the trap sections. Trap 10 can be mounted on a packaging board 36 for sale. The trap comprises a back section 12 , a floor section 16 , and a front section 18 . Floor section 16 is coated with bug adhesive 28 , depicted by dotted lines, and then covered with peel-off paper 32 . Front section 18 comprises full-length vertical struts 24 separated by vertical openings 20 a . Fold-over tab 34 runs horizontally along the bottom of vertical struts 24 and is coated with contact adhesive 29 and covered with peel-off paper 32 .
[0078] To use trap 10 shown in FIG. 10 , the customer removes it from packaging board 36 , and removes peel-off paper 32 from floor 16 and fold-over tab 34 . The customer folds back 12 upward and inward to about a 90° angle and folds front 18 inward and upward so that the top of front 18 is adjacent to the top of back 12 , leaving floor 16 horizontal and allowing tab 34 to extend beyond the top of back 12 . The customer then folds tab 34 down so that contact adhesive 29 thereon secures it to the top of the outside edge of back 12 . This creates a three-dimensional trap structure which can be placed in a suitable area for trapping spiders.
Examples
Example 1
Spider Trap Construction
[0079] It was hypothesized that glue traps employing cardboard would be suitable for attracting and trapping Loxosceles reclusa spiders. The motivation of this study was to determine improved three-dimensional shape(s) of cardboard traps for catching brown recluse spiders. Although reclusive and shy, L. reclusa have shown a preference for certain surfaces, such as cardboard, newspaper, lumber, and other Loxosceles species have shown similar preferences (Fischer et al. 2005). Of these choices, cardboard was chosen as the most practical and inexpensive choice for trap construction.
[0080] The effectiveness of several three-dimensional glue-trap shapes for trapping Loxosceles reclusa Gertsch and Mulaik (Araneae: Sicariidae), was investigated using four novel glue-trap shape designs, which were compared to an existing design currently on the market. These four novel and one standard shape designs were tested using pairwise comparisons. The most effective trap design was a flat glue-trap with no covering. The next most-effective trap was a trap with a front face comprising full-length parallel vertical struts. The trap comprising partial-length vertical struts with a horizontal bar was the third most effective embodiment.
Materials and Methods
[0081] All L. reclusa used in this study were caught in central or south-central Missouri, USA. While in the laboratory, they were fed a diet consisting of domestic house crickets ( Achetus domesticus ) and various species of shorthorned grasshoppers. A mixture of adult and juveniles spiders were used. Glue-trap designs were made using modified Catchmaster™ glue traps (catchmaster.com) cut into 6.67×13.49 cm rectangles and laser-produced cardboard cutouts from The Center for Rapid Product Realization at Western Carolina University.
[0082] The experimental roofed traps used 0.03″ non-corrugated chipboard pad cardboard (Uline, uline.com) laser cut to the specifications shown in FIGS. 1-4 . There were a total of five trap designs: flat (6.67×13.49 cm rectangle with no cardboard attached, FIG. 5 ), and traps with fronts having X-shaped (hourglass) struts ( FIG. 2 ) full-length vertical struts ( FIG. 3 ), partial-length vertical struts with a horizontal bar near the bottom ( FIG. 4 ), and regular Catchmaster™ traps ( FIG. 6 ), which were used as the control. The base of the trap was the same (6.67×13.49 cm rectangle) in each of the five designs.
[0083] For a paired comparison of traps, two spiders of the same gender and/or age group (males with males, females with females, juveniles with juveniles) were placed into a plastic bin measuring 30.48×45.72×30.48 cm and left to acclimate for approximately 12 hours. At that point, two traps of different designs were placed in the bin, one on either end, about 2.54 cm from the wall. Spiders were left for another 12 hours, and at the conclusion of that period, it was noted in which trap, if any, the spiders were caught. Each trap pairing was tested at least 50 times. Only spiders that did not choose a trap during their first experiment were used again. The experimental comparisons were performed in a laboratory setting to cut down on external stimuli that might have influenced trap choice, such as odors, air currents, temperature, etc.
Statistical Analysis
[0084] A Bradley-Terry model was fitted for paired comparisons in SAS© 9.2 (sas.com) with PROC LOGISTIC and PROC GENMOD, where ties (spider prefers neither trap) are removed. The Deviance and Pearson Goodness-of-Fit Statistics in PROC LOGISTIC yield p-values of 0.09 and 0.10 respectively, the Hosmer-Lemeshow p-value is 0.21, and the Lagrange Multiplier Statistic for non-intercept in PROC GENMOD yields a p-value of 0.03, which suggests that there may be a problem with the fit of the Bradley-Terry model.
Results and Discussion
[0085] The estimated preference probabilities obtained from the fitted model are listed in Table 1.
[0000] TABLE 1 Estimated preference probabilities obtained from the fitted model. Preferred trap design Design preferred over p X Vertical 0.43 Horizontal 0.45 Flat 0.25 Control 0.5 Vertical Horizontal 0.53 Flat 0.31 Control 0.58 Horizontal Flat 0.29 Control 0.55 Flat Control 0.75
The probabilities suggest the following ordering of the five traps for catching L. reclusa (least preferable to most preferable): Control< X trap< horizontal bar trap< vertical strut trap< flat trap.
[0086] In addition to the possible problem with the model mentioned above, there was a fairly high percentage of ties in the data set (Table 2).
[0000]
TABLE 2
Number of Trials and Ties
Comparison
Number of Trials
Number of Ties
X vs. Vertical
55
23
X vs. Horizontal
58
23
X vs. Flat
63
16
X vs. Control
50
13
Vertical vs. Horizontal
51
12
Vertical vs. Flat
50
13
Vertical vs. Control
50
9
Horizontal vs. Flat
55
9
Horizontal vs. Control
50
3
Flat vs. Control
50
14
[0087] As a result, an extended Bradley-Terry analysis that adjusted for ties was implemented in SAS. Here, a tie was interpreted to mean that each trap receives one-half of a choice. For example, assume that 50 trials were performed for a pair of traps, and the first trap was chosen 23 times, the second trap was chosen 22 times, and neither trap was chosen 5 times. In the adjustment for ties, pseudo-data were generated, where the first and second traps were chosen 25.5 and 24.5 times, respectively. Turner and Firth (2012) find that this simple and intuitive approach to handling ties works well in practice and generally yields results very similar to those obtained from much more sophisticated analyses, which have the disadvantage of being much harder to implement and interpret.
[0088] A Bradley-Terry model for paired comparisons was fit with the pseudo-data values in SAS. The Deviance and Pearson Goodness of-Fit Statistics in PROC LOGISTIC yielded p-values of 0.17 and 0.18 respectively, the Hosmer-Lemeshow p-value was 0.35, and the Lagrange Multiplier Statistic for non-intercept in PROC GENMOD yielded a p-value of 0.06. Obtaining insignificant p-values for each of the four goodness-of-fit procedures suggests that the extended Bradley-Terry model fits the data well.
[0089] The estimated preference probabilities obtained from the adjusted analysis are listed in Table 3.
[0000]
TABLE 3
Estimated Preference Probabilities
Obtained from the Adjusted Analysis
Preferred trap design
Design preferred over
p
X
Vertical
0.45
Horizontal
0.47
Flat
0.32
Control
0.51
Vertical
Horizontal
0.52
Flat
0.36
Control
0.56
Horizontal
Flat
0.34
Control
0.54
Flat
Control
0.69
[0090] The probabilities yielded the following ordering of the five traps for catching L. reclusa (least preferable to most preferable): Control< X trap< horizontal bar trap< vertical strut trap< flat trap.
[0091] In summary, analyses that excluded ties and analyses that included ties agreed on the same ordering of the traps. The flat trap was chosen more than the other traps in the pairwise comparisons (Table 4).
[0000]
TABLE 4
Trap Comparisons
Trap Pairings
X
Vertical
Horizontal
Flat
Control
X vs. Vertical
22%
36%
X vs. Horizontal
24%
32%
X vs. Flat
16%
56%
X vs. Control
46%
28%
Vertical vs. Horizontal
36%
40%
Vertical vs. Flat
30%
44%
Vertical vs. Control
44%
38%
Horizontal vs. Flat
14%
72%
Horizontal vs. Control
54%
40%
Flat vs. Control
46%
26%
[0092] However, the flat trap was the least user-friendly trap of those tested, since there was no barrier to prevent accidental glue contact from non-arthropod victims such as children, pets, etc. The other traps had some type of cardboard “roof” over the glue part, serving as a physical deterrent for unwary or inquisitive animals and/or children. The standard, unmodified control trap design performed poorly against all of the modified designs, even though it had a much larger glue perimeter (55.88 cm) and glue surface area. Exposed glue perimeters for the X, all vertical, vertical with horizontal bar, and flat traps were 18.42, 17.78, 19.69, and 36.83 cm, respectively. Perimeter comparisons can yield only a partial explanation for the differences in trap selection, because the flat trap had 53% more exposed perimeter than the other modified traps, yet it was chosen 14% more often than the horizontal bar trap design. It also outperformed the control trap, which had 66% more exposed perimeter than the flat trap. Also, the cardboard backs and struts on the other three modified traps may have facilitated spider escape, as there was no glue on those areas. The experimental roofed traps were constructed of chipboard cardboard, a different material than the commercial roofed traps, so the different results obtained with the experimental traps vs. the commercial traps cannot be ascribed solely to different design shapes.
Example 2
Comparison of Vertical Trap with Flat Traps
[0093] The objective of this study was to compare the performance of the vertical spider trap of the present invention with three commercial glue traps, Catchmaster (spider and insect trap, www.catchmaster.com/wpcproduct/mouse-insect-glue-boards/), PIC (GMT-2F Mouse Glue Board, www.amazon.com/PIC-GMT-2F-Mouse-Board-2-Pack/dp/B0037Z1F9A), and Tomcat (Glue Board, www.tomcatbrand.com/glue_boards.html). Materials and methods were as described in Example 1 except that the present vertical trap was tested against the three competing flat traps and 100 trials were conducted. In 41 of the 100 trials no spider was caught. Results are provided in Table 5.
[0000] TABLE 5 Comparison of Vertical Trap with Flat Glue Traps PIC Vertical Catchmaster Triangular prism Tomcat (This Rectangular (solid front, back Rectangular Type of Trap Invention) box and floor) box No. of trials 21 17 14 7 in which spider was caught
The results show superior performance by the novel vertical trap hereof.
[0094] The foregoing illustrates spider traps hereof and methods and kits for making them, as well as methods of catching spiders and reducing spider populations in indoor areas. The descriptions, examples and illustrations provided are not intended as an exhaustive description of every possible embodiment covered by the claims. Art-known and obvious equivalents to elements, components structures, parameters, and method steps are included within the scope of this invention which is defined by the attached claims.
REFERENCES
[0000]
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Vetter, R S, Barger D K. 2002. An infestation of 2,055 brown recluse spiders (Araneae: Sicariidae) and no envenomations in a Kansas home: Implications for bite diagnosis in regions of North America where the spider is not endemic. Clinical Infectious Diseases 39(6):948-951. 2002.
Zurek, L. 2005. Spiders and Scorpions. Kansas State University Agricultural Experiment Station and Cooperative Extension Service. MF-771: 1-3. | A trap for spiders and other insects is provided. The trap is especially useful for catching brown recluse ( Loxosceles reclusa ) spiders, whose bites are extremely harmful. The trap need not utilize chemical attractants or other behavior-modifying environmentally harmful chemicals, or food bait or lights to attract the spiders. In embodiments, the internal volume of the trap is shaped as a triangular prism with open triangular faces and openings in the front. At least a portion of the floor is coated with bug adhesive. The trap can be packaged as a kit including a flat sheet that can be folded a three-dimensional shape. In a useful embodiment the front includes spaced vertical struts. Methods and kits for making using the traps are also provided. | 56,326 |
BACKGROUND OF THE INVENTION
The present invention relates to infusion members and more particularly to a novel multi-angle U-shaped hub for an infusion member.
Conventional medical practice often requires an intravenous infusion to be performed to allow blood, nutriments or other desirable fluids to be fed directly into the vascular system of a patient being treated. A venipuncture is performed at a site on the patient's body and a hollow infusion member is inserted therethrough. Typically, a length of tubing is attached between the infusion member and a supply bottle located in the vicinity of the patient. It is extremely important to prevent lateral movement of the infusion member relative to the venipuncture site, to reduce abrasion and laceration of the flesh around the venipuncture site and so minimize its irritation and susceptibility to phlebitis, and to prevent inadvertent withdrawal of the infusion member, to minimize hematoma or blood loss.
It is known to provide a structure, adjacent to the junction of the infusion member and tube, to be grasped during the venipuncture operation. It is also known to utilize the structure to provide a surface for taping the junction region to the patient's body, after the infusion member had been inserted, to reduce the undesirable lateral movements thereof.
Desirable infusion apparatus should also utilize a structure allowing the infusion member and tube to be manufactured in an axially aligned condition, and still provide a doctor or technician complete choice of the final angular orientation of the infusion tube with respect to the infusion member. A medical practitioner, especially when preparing a patient for surgery, requires a choice of angles of the infusion tube relative to the infusion member. Various surgical procedures require that the infusion tube: remain axially aligned with the infusion member, as when the intravenous supply is positioned toward the lower extremity of the patient; have a 90° bend with respect to the axis of the infusion member, as when filters are attached thereto; have a 135° bend with respect to the infusion member axis, to allow the flexible tube to point towards the head of the operating table when the venipuncture site is situated in the outstretched arm of the patient; or have a 180° bend if the arm is at and parallel to the patient's side and the intravenous source is near the head of the patient. Thus, an infusion member hub capable of maintaining the flexible infusion tube at one of a plurality of angles relative to the axis of the infusion member, yet minimizing the radial pressure on the tube to prevent a pinch effect and subsequent decrease of both internal cross-section of and flow through the tube, is desirable.
BRIEF SUMMARY OF THE INVENTION
In accordance with the invention, a multi-angle U-shaped hub for an infusion member includes a plurality of clips generally equally spaced about the periphery of the hub and a projection extending from one corner of the hub to receive the junction of the infusion member, such as an intravenous needle, a sheathed needle, a cannula, a catheter, a styletto-catheter or the like, with a flexible length of infusion tube. The infusion tube and infusion member are initially in axial alignment. Each of the hub clips has a radially disposed slot, of a width less than the outer diameter of the tube, which slot communicates with a generally circular aperture having a diameter at least equal to the outer diameter of the flexible tube and formed in each hub clip parallel to the hub periphery. The infusion tube is inserted through the slot into the aperture of a successively larger total of the hub clips to enable the tube to be bent through and maintained at successively greater angles relative to the axis of the infusion member. The diameter of the aperture is selected to prevent pinching of the wall of the infusion tube.
In a preferred embodiment, a semi-circular hub is provided with four hub clips. Each clip is positioned to have a 45° angular rotation along the curved hub periphery relative to the adjacent hub clips or to the hub protrusion.
In another preferred embodiment, the hub protrusion encloses the junction between the flexible infusion tube and a male standard cannula connector to provide the advantages of the multi-angle hub while enabling the practitioner to select one of a variety of standard rigid or flexible cannulae for attachment to the standard connector.
In still another preferred embodiment, a shaped collar is formed about the junction of the infusion member and infusion tube, or an intermediate portion of an infusion combination. The hub protrusion includes a flanged recess adapted to forcefittedly receive and lock the shaped collar to the multi-angle hub, thereby enabling insertion and removal of one of a plurality of infusion combinations, and reuse of the hub and/or infusion member.
In yet another preferred embodiment, the infusion member is a single lumen catheter having a slidably retractable but non-removable stylette contained in a secondary channel formed completely within the catheter wall; the hub protrusion includes a cooperatively formed recess in communication with the stylette channel for enabling the passage of the proximal end of the stylette through the protrusion whereby the sharp stylette tip may be withdrawn a short distance into its secondary channel after the venipuncture has been performed. This novel styletto-catheter may be utilized separate from the novel hub.
Accordingly, it is an object of the present invention to provide a novel hub for an infusion member and infusion tube.
It is another object of the present invention to provide a novel infusion hub allowing an infusion tube to be maintained at one of a plurality of angular orientations with respect to the axis of an infusion member.
It is yet another object of the present invention to provide a hub having means for detachably receiving one of a variety of infusion tube-infusion member combinations to provide for reuse of the hub.
It is a further object of the present invention to provide a novel styletto-catheter having its stylette slidably received within a secondary channel formed within the wall of a single lumen catheter.
It is a still further object of the present invention to provide a styletto-catheter in apparatus allowing a flexible infusion tube to be maintained at one of a plurality of angular orientations with respect to the axis of the catheter lumen.
These and other objects of the present invention will become apparent in reading the accompanying detailed description and the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a plan view of a multi-angle U-shaped hub for an infusion member and infusion tube in accordance with the principles of the present invention.
FIG. 1a is a plan view of the hub of FIG. 1 and illustrating the manner in which the infusion tube is retained at a plurality of angular orientations with respect to the axis of the infusion member;
FIG. 2 is an enlarged cross-sectional view of the hub taken along line 2--2 of FIG. 1;
FIG. 3 is an enlarged cross-sectional view of the hub, infusion member and infusion tube taken along line 3--3 of FIG. 1;
FIG. 4 is an exploded perspective view of the hub utilizing a novel styletto-catheter and illustrating a method for the manufacture thereof;
FIG. 5 is a plan view of another embodiment of hub having means for detachable mounting an infusion combination to the hub protrusion, and a partially-sectionalized view of one such infusion combination;
FIG. 6 is an enlarged cross-sectional view of the hub taken along line 6--6 of FIG. 5;
FIG. 7 is an exploded perspective view of another means for detachably mounting an infusion combination to a protrusion on the periphery of the multi-angle hub of the present invention;
FIGS. 8 and 8a are cross-sectional views of the hub and novel styletto-catheter in the extended and retracted conditions, respectively;
FIG. 9 is a cross-sectional view of the styletto-catheter taken along line 9--9 of FIG. 8a;
FIGS. 9a and 9b are cross-sectional views of alternative embodiments of the styletto-catheter;
FIG. 10 is a cross-sectional view of another embodiment of a styletto-catheter in accordance with the principles of the invention and for use separate from the U-shaped hub;
FIG. 11 is a cross-sectional view of the styletto-catheter taken along line 11--11 of FIG. 7; and
FIGS. 11a and 11b are cross-sectional views of alternative embodiments of the styletto-catheter utilizing the principles of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIGS. 1-3, a preferred embodiment of multi-angle U-shaped hub 10 comprises a generally semicircular portion 11 formed of a relatively inflexible and lightweight material, such as plastic or the like, and having generally parallel upper and lower smooth surfaces 11a and 11b, respectively. A projection 12 integrally extends from a portion of hub periphery 14 adjacent to a first corner 11c formed between the periphery and the diametric edge 16. A plurality of clips 18a-18d respectively extend radially outward from hub periphery 14.
A hollow infusion member 20, such as a needle; a cannula; a catheter with or without centrally placed removable trochar, stylette or needle; a sheathed needle; a styletto-catheter or the like, has a bevelled or flat distal end 21 and a proximal end 22 having attachment means 22a such as a flared skirt, hub or the like. A length of flexible infusion tubing 25 has an outer diameter D 1 . One end 27 of the tube includes hub means 28, such as a standard universal female intravenous tube coupling having a converging interior passage 29 for force-fittingly receiving the nipple, such as a Luer fitting or the like, of a tube running from an intravenous supply bottle or the like (not shown for reasons of simplicity). The proximal end 22 of infusion member 20 is adapted to closely receive and form a substantially liquid-tight seal to a forward end 30 of tube 25. It should be understood that a separate infusion member 20 and infusion tube 25 are shown for the purposes of illustration only; the wall and channel of tube 25 may extend in uninterrupted fashion completely through hub protrusion 12 to form a flexible cannula, as the hollow infusion member 20. In general, hub protrusion 12 receives an infusion combination, which combination is defined herein as any infusion tube in fluid-flow connection with either an infusion member or means for coupling an infusion member to the tube. Usually a more rigid stylette or hollow needle is kept within the infusion member during insertion and removed after insertion in the vein.
Hub protrusion 12 surrounds and encases the junction between infusion member proximal end 22 and infusion tubing forward end 30. The protrusion is preferably molded around the previously joined infusion member and tube to provide a high quality liquid-tight seal.
Each hub clip 18 has a selected value of angular rotation along curved periphery 14 with respect to both the adjacent hub clips and to a reference line 12a at protrusion 12. Thus, a first clip 18a is situated at an angle α with respect to reference line 12a; a second clip 18b is situated with an angle β with respect to first clip 18a; a third clip 18c is situated with an angle γ with respect to second clip 18b; and a fourth clip 18d is situated with an angle δ with respect to third clip 18c, for hub having four hub clips 18. It should be understood that this novel hub for infusion member may be provided with one clip, or plurality of clips 18 and that the angles formed between adjacent clips and between a clip and the hub protrusion may be selected as required for a range of end uses. In a preferred embodiment, the hub includes four clips having equal angles with each other and with reference line 12a, i.e., α=β=γ=δ, and each angle is approximately fourty-five degrees.
Each hub clip 18 has an aperture 35, of diameter D 2 , formed therethrough parallel to hub periphery 14. Aperture diameter D 2 is selected to be substantially equal to, but never less than, the outer diameter of D 1 of infusion tube 25, whereby pressure tending to pinch infusion tube 25 partially or completely closed is avoided when the infusion tube is positioned within aperture 35. A slot 36 is formed through the radially outermost remaining portion of clip 18 to allow tube 25 to be pressed into aperture 35. Slot 36 has a gap distance G selected to allow tube 25 to pass therethrough only when tube 25 is forcibly compressed, whereby the tube is maintained within the aperture if external compression force is not applied. Preferably, the material utilized for the formation of the hub, and particularly for clips 18, is highly resilient to absorb shock forces tending to tear tube 25 from each clip 18 through which the tube has been positioned.
In use, opposite surfaces 11a and 11b of the hub are grasped to allow insertion of infusion member 20. A solid or hollow trocar member 35 may be required to perform the puncture, particularly if the infusion member 20 is a flexible catheter or the like. The bevelled cutting edge 35a of the trocar is inserted through the axially aligned lumens of tube 25 and infusion member 20 to extend forward of infusion member forward end 21. After the puncture has been performed, and the trocar removed, infusion tube coupling 28 is attached to a supply bottle or the like (not shown). It should be understood that known means may be employed with tube 25 and its coupling 28 to temporarily seal the lumen and prevent liquid outflow after the puncture has been completed but before connection has been made to the coupling. One of smooth hub surfaces 11a or 11b is then placed against the patient's skin and the hub is secured in place by means external to the hub (not shown). Alternatively, surfaces 11a and/or 11b may be slightly concave to make pinching more comfortable. And in another alternative, one or both of hub surfaces 11a, 11b are coated with a layer of adhesive material 38 and covered with a protective layer 39; protective layer 39 is removed and hub 10 is pressed against the patient's skin to allow adhesive layer 38 to adhere thereto and hole the hub in place to absorb the forces of lateral movement.
Having inserted infusion member 20 and secured hub 10 to the patient's body, the physician or medical technician now bends tube 25 into position against the slot 36 formed in the first clip 18a and presses the tubing therethrough to be retained within aperture 35 (FIG. 1a); the axis B of infusion tube 25 is now held at a bend angle θ with respect to the axis A of infusion member 20, having been gently bent at region 25a to prevent buckling of the tube wall and ensuing diminution of infusion flow. A larger bend angle θ is achieved as tube 25 is engaged within the apertures of clips 18 having greater angles of rotation from protrusion 12. Thus, in the illustrative examples, θ is 45° when tube 25 is held only by clip 18a. Tube 25' forms an angle θ equal to 90° when positioned in the apertures of both clips 18a and 18b; θ = 135° when tube 25" is positioned in the apertures of clips 18a, 18b and 18c; and θ = 180° when tube 25'" is positioned through the apertures of all four clips 18a-18d.
In one preferred embodiment (FIG. 4), multi-angle hub 10 is formed of a semi-circular blank 50 having a thickness T 1 . Protrusion 51, having a greater thickness T, is formed along the curved periphery of member 50 and encloses the junction between an infusion member 52, such as a styletto-catheter, and an infusion tube 53. Each or a pair of matched clip members 55a and 55b has a central semi-circular portion 56 and 56', respectively, of thickness T 2 and have a like plurality of fingers 57 extending from their respective curved peripheries 56a and 56'a of portions 56 and 56' -- the position of clip fingers 57a-57d on each of periphery 56a, 56a' being complementary about an axis C passing through the midpoint of each diametric side 56b', 56b' and perpendicular thereto. Each clip finger 57 includes a radially extended portion 58 integrally joined to a semi-circular portion 56 or 56' and a second portion 59 extended perpendicular to the plane of the portion at the radially outermost end of first portion 58. A curved portion 60 fills the inside corner formed by portions 58 and 59 and has a radius of curvature essentially equal to one-half the outer diameter D 1 of tube 25.
A matched pair of clip members 55a and 55b are arranged with their respective clip finger second portions 59 facing each other, and are fastened by means of a suitable cement, solvent, thermal weld or the like to opposite faces 50a, 50b of hub member 50. It should be evident that a large selection of final hub assemblies 10 can be formed by manufacturing a plurality of different hub members 50 and another plurality of different matched pairs of clip members 55. Each hub member 50 has a particular combination of infusion member 52 and length and type of infusion tube 53 and may be utilized with a pair of matched clip members 55 selected from the plurality of such clip member pins having the same radius but utilizing different numbers and positions of clip portions 57. The clip member thickness T 2 and hub member thickness T 1 are selected such that T 1 + T z = T, the protrusion thickness, to yield a hub having smooth upper and lower surfaces 11a, 11b (FIG. 2). The length L of each clip second portion 59 is selected according to the formula L = 1/2 (T-G) to provide for a suitable slot 36 through which tube 25 may enter the clip.
Referring now to FIGS. 5 and 6, wherein like reference numerals are utilized for like elements, another embodiment of multi-angle infusion hub 10' includes a hub protrusion 12' integrally extended from a portion of hub periphery 14 adjacent to the first corner 11c formed between the periphery and diametric edge 16. Hub protrusion 12' has a cross-section similar to each hub clip 18 and includes an aperture 35 of diameter D 2 formed therethrough parallel to hub periphery 14 and a slot 36' formed through the radially outermost remaining portion of hub protrusion 12'. An intermediate portion 25a of tube 25', between distal end 30' and proximal end 27', is forcibly compressed and inserted within protrusion aperture 35' and maintained therein by the resiliency of the material forming protrusion 12', in the absence of external compression force.
A male standard cannula connector 62 has a converging forward portion 62a and a tube coupling portion 62b of reduced diameter force-fittedly received within the lumen of distal end 30 of infusion tube 25'. Portion 62 may also be cemented, bonded by solvent or thermally welded to distal end 30. The outer diameter D 3 of coupling portion 62b is at least equal to the bore diameter of flexible tubing 25', to insure a liquid-tight connection therebetween. The standard connector 62 is adapted to accept a wide variety of rigid or flexible standard cannulae (not shown). If force-fittedly secured, the selected cannula may be removed from standard connector 62 to allow the hub, tube and connector combination to be reused, or the tube-connector combination may be pressed outwardly from channel 35' and be disposed of, allowing reuse of hub 10'.
Referring now to FIG. 7, a collar 64 has a flat upper surface 64a of width W 1 and a tapering lower portion 64b having a keel-like projection 64c to control rolling or turning. The collar may be molded around the junction between an infusion member and infusion tube to provide the required liquid-tight connection, or, as illustrated, may be molded about an intermediate portion of a continuous length of flexible infusion tube 25" to form part of an infusion combination. Hub member 10" has a flat surfaced diametric edge 16" and includes a hub protrusion 12" having a recess 65 of similar cross-section to collar 64 including keel 64c. Recess 65 is formed into protrusion 12" perpendicular to flat surface 16". A circular channel 35" axially extends in either direction from recess 65 and a slot 36" is formed through the radially outermost remaining portion of hub protrusion 12" to allow tube 25" to enter channel 35". A flanged edge 66 is formed along the length of the rectangular opening of recess 65 in the radially outermost surface 12b of hub protrusion 12'. The flanged edges reduce the width of recess 65 to a width W 2 less than the width W 1 of the remaining portion of the recess and of collar 64.
In use, collar 64 is pressed into recess 65 with its keel 64c and then its converging portion 64b initially entering the recess. The insertion is aided by the resiliency of the material utilized for the hub member. Upon further application of force, collar 64 fully enters recess 65 and flange portion 66 resiliently snap-locks over peripheral edge portions of the top surface 64a of molded collar 64, to prevent radial movement of collar 64 within recess 65, while the remaining portions of hub protrusion 12" prevent axial and rotational movement of the collar and the encased tube 25'. The resilient material of hub protrusion 12" is forced apart adjacent top surface 12 to allow collar 64 and the attached tube 25" to be removed from recess 65 and discarded whereby multi-angle hub 10" may be reused.
I have found that a particularly advantageous infusion member for use with my novel, multi-angle U-shaped hub 10 is a styletto-catheter 52 (FIG. 8) having a generally flexible infusion portion 70 integrally joined with infusion tube 53 which is of variable length and has a female I.V. connection at proximal end 53a. Infusion portion 70 has a smooth exterior surface 70a and may be of any geometric cross-section, including circular (FIG. 9), square (FIG. 9a), oval (FIG. 9b) or triangular (FIG. 11a) cross-section. A secondary channel 71 is formed within a thickened portion 72 of the tube wall and extends parallel to the lumen of infusion member 52 from distal end 73 into a communicating recess 75 formed in hub member protrusion 51. The cross-sectional area of secondary channel 71 is usually, but not always, less than the cross-sectional area of catheter lumen 70a whereby the magnitude of lumenal flow is at most slightly reduced.
A semi-rigid metallic stylette 80 has a cross-sectional shape selected to be closely received within the bore of secondary channel 71. Thus, a first stylette 80 has an oval cross-section for use in oval cross-section secondary channel 71 formed in a portion of the wall 72 of a circular cross-section catheter 52 (FIG. 9); another catheter 52' of square cross-section (FIG. 9a) has a secondary channel 71' formed with a rectangular cross-section to closely receive a stylette 80' having a cooperative rectangular cross-section; and a third catheter 52" (FIG. 9b) has a secondary channel 71" of highly eccentric oval cross-section to closely receive a stylette 80" having a cooperative oval cross-section.
The distal end 81 of stylette 80 is bevelled and sharpened to enable a venipuncture to be performed even when infusion portion 70 is formed of a flexible material. Stylette 80 is bent to allow its proximal end 82 to extend through recess 75 in a direction substantially perpendicular to the axial direction of infusion member 52 and away from the top surface 51a of protrusion 51.
The length of stylette 80 is selected to allow distal end 81 to extend forward of catheter end 73 when stylette extension 82 is urged against the forward wall 75a of recess 75. The length S of recess 75 is selected to allow complete withdrawal of distal end 81 within secondary channel 71 when extension 82 is urged against the rear walls 75b of recess 75. Stylette 80 cannot be removed in normal use and remains rigidly positioned within secondary channel 71 to resist and prevent kinking and twisting movement of infusion portion 70, while distal end 81 is enclosed and protected by the forward portion 70b of the catheter whereby danger of laceration to the surrounding tissue is reduced. The width of a styletto 80 may be maximized for formation of a puncture having a size approaching the cross-sectional area of the catheter, for ease of insertion thereof.
In another preferred embodiment, a styletto-catheter 90 (FIG. 10) is utilized independent of hub 10. Styletto-catheter 90 comprises a flexible tube 91 having a catheter lumen 92 generally axially formed therethrough. Tube 91 has a bevelled distal end 91a and a flared proximal end 91b adapted to force-fittingly receive a standard male intravenous coupling 93 in axial connection. A portion 94 of the catheter wall is gradually thickened to extend into lumen 92. At least one secondary channel 95 is axially formed within thickened wall portion 94. A flexible stylette member 96 is positioned within each secondary channel 95. The distal end 96a of stylette 96 is sharpened to enable formation of a venipuncture or the like, and the proximal end 96b of stylette 96 is bent to extend radially away from the axis of lumen 92. A recess 91c is formed in the wall of catheter 91 adjacent to stylette extension 96b to enable the stylette to be urged toward catheter tip 91a until stylette tip 96a protrudes therefrom for the cutting operation. The stylette is withdrawn along secondary channel 95 only until stylette extension 96b abuts a protrusion 97, to prevent complete removal of the stylette. It should be understood that the resiliency of the material utilized in the formation of catheter 91 is sufficiently high to cooperate with the exterior surface of stylette 96 to form a liquid-tight seal to prevent fluid passage along the secondary channel.
Styletto-catheter 90 may utilize a single stylette 96 emplaced within a single secondary channel 95 (FIGS. 11 and 11a), or may advantageously utilize a pair of independently movable stylettes 96,96' (FIG. 11b), each independently slidably enclosed within its own secondary channel 95, 95' formed within a like number of thickened portions 94, 94' in the wall of the catheter.
The shape, number and position of the stylettes are chosen for the required end use. The cross-sectional area of the thickened wall portion 94 (of 71 of FIG. 8 and 8a), and hence of stylette 80 or 96, may be selected to decrease the cross-sectional area of the lumen 92 of the catheter by an insignificant amount, or may be selected to allow use of a stylette 96 having a greater width than the width of the lumen 92, to form a large area puncture for ease of catheter insertion. Each stylette may advantageously be V-shaped (FIG. 11a) to cut a flat of skin, to even further enlarge the puncture area for ease of catheter insertion.
There has just been described a novel, multi-angle U-shaped hub for an infusion member and tube, allowing the infusion tube to be maintained at one of a plurality of angular orientations with respect to the axis of the infusion member. A novel styletto-catheter having its stylette slidably received within a secondary channel formed within a wall of a single-lumen catheter is described, which styletto-catheter may be used either with the U-shaped hub or independently.
The present invention has been described in connection with several preferred embodiments thereof; many variations and modifications will now become apparent to those skilled in the art. It is preferred, therefore, the present invention be limited not by the specific disclosure herein, but only by the appended claims. | A U-shaped hub has a plurality of clips formed along its exterior periphery to selectively receive an infusion tube at one of a like plurality of fixed angles relative to a protrusion extending from the periphery of the hub. The junction of the infusion tube and a hollow infusion member, such as an intravenous needle, a sheathed needle, a catheter, a cannula, a styletto-catheter or the like, is embedded within the hub projection. The channel diameter of each hub clip is substantially equal to the outer diameter of the flexible infusion tube to prevent collapse of the tube wall while enabling the initially straight tube to be bent and retained at one of a plurality of angles with respect to the center line of the infusion member to permit the use of a direct tubing connection between an intravenous source and the infusion member and for reducing the danger of lateral movement of the infusion member relative to the body. A novel styletto-catheter having a slidably retractable but non-removable stylette positioned in a separate channel within the wall of the catheter lumen is disclosed for use either with or without the U-shaped hub. The non-removable stylette prevents kinking, twisting and shape-distortion of the infusion member after the insertion thereof. | 28,110 |
This is a continuation of co-pending application Ser. No. 07/343,663 filed on Apr. 27, 1989, now U.S. Pat. No. 5,245,329.
BACKGROUND OF THE INVENTION
This invention relates to access control, and more particularly it is concerned with a high security access control system involving credit card type keys or mechanical keys and locks as well as keyholder authentication to prevent unauthorized use of a key.
A number of different types of access control systems and devices have existed in use or in previous patents--for example, the systems of National Computer Systems, Inc. and Continental Instruments, Inc.
Cylinders and keys having mechanical configuration in combination with electrical, magnetic or optical locking or unlocking devices have also been known. See, for example, U.S. Pat. Nos. 4,603,564, 4,658,105, 4,633,687, 4,458,512, and 3,733,862. In some of these devices, keys and cylinders could be coded by the manufacturer or by the user, with the non-mechanical aspect of the key affording additional security against opening of a lock without the proper key. In these combinations of mechanical and non-mechanical security features on a key, the non-mechanical code or configuration or pattern simply added to what was required to open the lock, generally not carrying other readable data useful for other purposes.
U.S. Pat. No. 4,537,484 shows one example of a fingerprint reader system for use in identity verification. Another such reader is manufactured by ThumbScan, Inc. of Oakbrook Terrace, Ill., for the purpose of computer terminal security. Such scanners have also been suggested for use in identification in access control systems involving granting of entry only to authorized persons. However, these systems have not cooperated with keys and locks which could be used in the same facility. Also, they have generally required processing of the attempted user's fingerprint in a central processor which would have to either compare the attempted user's fingerprint with hundreds or thousands of stored fingerprints in a database, or would receive a user identification number keypunched in by the person seeking access, and then look up a database-stored fingerprint corresponding to that code and make the comparison. Such a central look-up and comparison would involve a great deal of central computer memory and power, and the use of many-conductor bus cables between each access control point and the central processor, and would tend to require considerable time or a very high powered computer, to complete the access control decision. This equipment and installation of the cables can involve great cost, particularly when added to an existing building.
A different approach to access control decision making is taken by the present invention described below. In a preferred embodiment, a keyholder carries a key which not only has a mechanical configuration for accessing mechanical locks (or a card type key with non-mechanical lock access features), but also carries encoded data representing a personal identifying code or feature of the keyholder, as well as a simple identity number or code. The high security authentication comparison can be made directly at the access control point, by a small processor board located behind a reader panel.
SUMMARY OF THE INVENTION
In accordance with the access control system of the present invention, the system includes a series of mechanical keys or card type keys (electronic, magnetic, hole-punched, etc.) which can optionally be high security keys themselves. At least some of the keys carry encoded data which represent a personal feature of the intended keyholder assigned to that key. In preferred embodiments, the personal identifying or authenticating feature of the keyholder is a "biometric" feature, such as a fingerprint, a retina scan, a facial photograph or other feature unique to the intended keyholder. A retina scanner is disclosed in U.S. Pat. No. 4,685,140, for example.
The encoded data preferably is placed on the bottom edge of a mechanical key, and may it be in a groove formed in that edge of the key. Alternatively, the data may be placed on one surface of the key's head. It may be read by swiping it through a reader slot. On a card type key the encoded data can be in a stripe on the card surface. Optical data storage such as used in audio and video discs may be used, or high-density optical storage such as disclosed in U.S. Pat. Nos. 4,145,758, 4,304,848 or 4,503,135.
The key also has a mechanical configuration (or lock accessing feature) matched to certain mechanical lock cylinders (or non-mechanical locks) to which the intended keyholder is to have access. Some of these may be lower security areas, and some may combine the mechanical or non-mechanical lock features with the user authentication access control feature, for high security.
It is a central feature of the present invention, and an important distinction from prior access control systems or high-security keys, that the key itself bears encoded data which is not merely picked up by the lock apparatus to establish a higher security in allowing rotation of a lock cylinder (or opening of a non-mechanical lock), but which carries digitized information relating to a personal authenticating feature of the intended user of the key, for reading and making a comparison before access is granted to the attempted user.
At some high-security access control point in the system, the keyholder places his key into a keyway or slot or against a reader, which reads the encoded, digitized information which relates specifically to the intended keyholder. This information as read is briefly stored in a memory associated with a small processor connected to the key reader. The keyholder may then be prompted to place a selected finger against a transparent window of a fingerprint reader. The fingerprint reader scans the fingerprint, and this scanned information is compared with the encoded information. It should be understood that other features unique to the intended keyholder can be used, as mentioned above such as a retina scan or a photograph.
If the actual fingerprint as read matches sufficiently closely to the fingerprint as encoded and stored on the key, a provisional decision is made by the small processor to grant access to the keyholder. In some applications a time/date access decision will also be required, with that decision made by a central processor, based on whether the particular keyholder is to be permitted access to that area at that particular time.
Optionally the keyholder can also be required to use his key to access a lock at the same location. The key can be used to rotate one cylinder, for example, while a second lock or bolt is released electrically, automatically, based on the decision of the system to grant access.
In a preferred embodiment the keyholder can be granted access by an electric release or electric strike based on the positive user authentication decision (with or without time/date decision from a central processor, as above), without using the mechanical key configuration (or other lock accessing features). In this case, the mechanical key configuration is used for other locks in the system, wherein lower security is required, with the encoded key enabling the keyholder to carry only one item for access to all permissible locks. With the authentication comparison made directly at the access control point, and no personal authentication (e.g., fingerprint) data required to be imported from any remote database at a central computer, the access control system of the invention can employ only a very small cable connecting each access control point to the central processor, e.g. two conductors, for time/date decision from the central processor and for reports to the central processor. Whenever access is attempted, the small local processor at the access control point can send a report which includes an identification of the keyholder, derived from encoded information on the key, and a "yes" or "no" decision as to whether access was permitted. The time of day and the access control point location can be added to the report by the central processor.
The system also enables access management for allowing different personnel entry at different times of day or different days of the week or calendar days, etc. The small on-site processor can be programmed to allow access to certain personnel by personnel code or number (at certain times), but preferably, for large numbers of personnel this is controlled by the central processor (again via a simple two-conductor cable). This can be adjusted, or access can be canceled for certain personnel (such as discharged employees) by instruction input at the central processor.
In another preferred embodiment of the invention, at each high-security access control point there is a keyway configured specifically for keys of keyholders who are to have access at this point. The keyway is at the key reader, instead of (or in addition to) the keyway being in a lock cylinder. When a key of the correct type is inserted into this keyway, the reader scans the encoded data. Keys of the wrong mechanical configuration cannot be inserted, so that access will not be possible. The keyway can be of a high-security type, rather than one in common use.
In addition, a high-security key cut configuration can be used, such as of the type shown in U.S. Pat. Nos. 4,635,455 and 4,732,022 assigned to Medeco Security Locks, Inc. Such key cuts are made at an oblique angle with respect to the side faces of the key. For the purposes of this invention, at least one pin can be cooperative with the keyway, with the pin having an angled bottom end which becomes rotationally oriented when it engages against the angle cut key. If the pin does not engage properly against the key's angle cut, access can be automatically denied (even though the keyholder identification will preferably still be read from the key). This enables a report to be made to the central processor, regarding the attempted entry, and the fact that a certain keyholder's key was apparently defective or was attempted to be used improperly, at the wrong access control point.
An alarm can be activated under such condition of attempted improper key use, or a silent signal can be sent elsewhere in the system where preferably personnel will be alerted.
The same alarm or signal can be sent whenever access is denied in any of the various forms of the system of the invention, and for any reason, including the reason that the keyholder's fingerprint (or other personnel identifier) did not match the code on the key.
If desired for extra security, the keyway provided at the key code reader can comprise an actual lock cylinder which must be rotated before a positive access decision can be completed. Such a cylinder can include a full compliment of pins in a nigh-security configuration if desired, so that a combination of user authentication and mechanical keying is relied upon for added security.
In one aspect, the invention comprises a card type or mechanical key, either of the pin type or of other high-security type currently in use, such as the dimple type or the tubular type, in combination with encoded data secured to the key--data which is readable by a scanner or reader and which does not directly help enable the keyholder to rotate the key in a lock. Instead, the encoded data is representative of some personal identifying, authenticating feature known by or held by or on the person of the intended keyholder. Such an authenticating feature preferably comprises a biometric feature such as a fingerprint scan, a retina scan, a voice pattern or a facial photograph; more broadly speaking, however, it can include other items such as a memorized number or code which is known only to the intended keyholder or keyholders and which must be input to a keyboard by the keyholder to be matched with what is read from the key. The prior art did not contemplate a mechanical key which itself bore such separate data which would enable authentication of the keyholder attempting access.
The encoded information on the key, if it represents fingerprint, retina scan, voice or other characteristic of the intended keyholder, also preferably includes a central keyholder number or code, for the purpose of reporting the identity of the intended keyholder in a transaction record whenever the key is attempted to be used for access.
In another aspect the invention comprises a card type key having normal lock accessing features, encoded data relating to the personal authenticating feature, and a photograph of the intended user, with other appropriate printed matter to allow the card to be used as an identifying card or badge. In a still further aspect, the card can at a minimum have encoded data carrying a biometric feature to be used in an access control system of the invention having corresponding biometric readers (e.g. fingerprint).
It is therefore among the objects of the present invention to improve over previous access control systems and high-security mechanical key systems by encoding keys with a user authentication code which can be read by scanners or readers at access control points, so as to prevent anyone but an authorized, intended keyholder from gaining access at such control points. An associated object is to provide an access control system wherein the key configuration or access control feature is effective to open locks at other points where keyholder authentication is not required, thus enabling personnel to carry only one key for access to both high-security points and lower-security points. These and other objects, advantages and features of the invention will be apparent from the following description of preferred embodiments, considered along with the accompanying drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic drawing indicating components of an overall access control system in accordance with the principles of the present invention.
FIG. 2 is a view showing a mechanical key forming a part of the system of the invention in one embodiment, with encoded data formed on or secured to the key.
FIG. 3 is a frontal elevation view illustrating elements of the system of the invention in a preferred embodiment, at one access control point in the system.
FIG. 4 is a schematic system diagram partially in the form of a block diagram, indicating several access control points and security components, and indicating some information and control flow to and from a central processor, in accordance with one embodiment of the system of the invention.
FIG. 5 is a schematic block diagram indicating information which might be included in the encoded data on the mechanical key indicated in FIG. 2, and illustrating flow of information from the key and from a fingerprint scanner which may be included, and showing operation of the system to grant access or deny access and to make reports.
FIG. 6 is a schematic view, partially in perspective, showing elements of an optical key reader which may be included in the system of the invention.
FIG. 7 is a schematic diagram showing an embodiment of a system of the invention wherein access control points are formed into groups.
FIG. 8 is a flow diagram indicating operation of the system in accordance with one preferred embodiment of the invention.
FIG. 9 is a flow diagram illustrating the use of the access control system of the invention with an employee time management and payroll system.
FIG. 10 is a perspective view showing a credit card type key with non-mechanical lock access features and with encoded data representing a personal identifying feature of-the keyholder.
FIG. 11 is a view similar to FIG. 10, showing a card with encoded data representing a personal biometric identifying feature of the keyholder and also a photograph of the keyholder, so that the card can be used as a security pass as well as an authenticating pass for high security access.
DESCRIPTION OF PREFERRED EMBODIMENTS
In the drawings, FIG. 1 shows schematically an access control system 10 in accordance with one embodiment of the present invention. Principal components of the system 10 include a series of high security access control points 12, including different security levels at 12a and 12b, and a series of lower security access control points 14. The system also includes a central processor unit 15 with associated memory, as well as a number of distributed mechanical keys 16 which are controlled in distribution and each registered to a specific intended keyholder or keyholders.
As schematically indicated in FIG. 1, the processor unit 15 is connected only to the high security access control points 12. The processor 15 may have a programmer unit 17 and an optional printer 18 connected to it.
As illustrated in FIG. 2, a mechanical key 16 as used in the system includes a mechanical configuration 19 for engagement with a mechanical lock, and it also includes encoded data related to high security access control located, for example, at a position 20 on or in the bottom edge of the key 16. The encoded data may alternatively be located on the head 22 of the key or on another edge, such as edges 24 of the key head 22. In these alternate locations the encoded data can be read by placing the key against a reader, or by insertion into a slot or by swiping through a slot.
Although FIG. 2 shows a conventional mechanical key configuration, for use with pin and shear plane type rotatable lock cylinders, the mechanical key 16 can also be of the higher security type with angle cuts as shown in U.S. Pat. No. 4,732,022 referenced above, or it can be a tube-shaped key of type often used on computers and burglar alarms, etc., or a dimple type key or any other type of mechanical key.
It should be understood that the present invention also applies to credit card type keys, hole punched type flat keys, and other flat plastic or metal card type keys, as well as conventional mechanical keys. The term "key" as used herein and in the claims is intended to encompass all such keys, except accompanies by the term "mechanical."
An example of one kind of credit card type key 16a is shown in FIG. 10. All of FIGS. 1 and 3 through 9, and the accompanying description, should be understood as encompassing the use of any of a number of such card type keys, in many different configurations and with different types of lock accessing features. The card type key 16a in FIG. 10 may have hole-punched type lock access features 21, and a small strip of encoded data 23 carrying the personal identifying feature, such as a biometric feature.
Each key has two separate functions--a mechanical function of opening mechanical (or magnetic, hole-punch, etc.) locks in the system, and an electronic or data function involving the carrying of data as discussed above. The data borne by the key 16, in accordance with preferred embodiments of the invention, does not itself open a lock or help enable opening of a lock or enable access at an access control point. Rather, it includes information specific to the intended keyholder, for authenticating the keyholder when access is attempted by a keyholder using the key. At the minimum, the encoded data will include a personal code, e.g. a combination of numbers which are memorized by the intended keyholder and which only the intended keyholder (and perhaps supervisory personnel) is supposed to know. A comparison is made between the encoded information, or some of the encoded information from the key, and similar information input in another way (e.g. input manually by the keyholder on a number keyboard or input via fingerprint).
Thus, the system of invention differs from prior systems, even in the form of the minimum system just described, in that when access is attempted, the system does not retrieve a secret code from a central database or processor, for comparison with a code input by the attempted user. Instead, the secret code is carried on the key itself, and can be read by a small local processor at the access control point and there compared directly with a code input by the attempted user. The on-site comparison is one important feature of the invention.
However, in preferred embodiments of the invention the keyholder authenticating data carries not merely a secret number or code memorized by and known only to the intended keyholder, but instead or in addition carries data related to a personal identifying characteristic or biometric feature of the intended keyholder. This identifying biometric feature or characteristic advantageously can be the intended keyholder's fingerprint, but it could also be any other unique personal characteristic as discussed above, such as a digitized facial photograph or a voice pattern or even a retina scan.
At each high-security access control point in such a preferred system, there is provided both a key reader for reading the encoded data on the key, and a reader of the attempted user's biometric feature such as fingerprint, voice pattern, photograph, retina scan, etc. FIG. 3, showing an example of a high-security access control point, shows a fingerprint reader window 25 and a keyway 26 for reading of the encoded data on the key. A reader panel 28 shown in FIG. 3 also may include an optional key pad 30, for manually inputting a code, which can be an alternative to a fingerprint reader or other personal identifying feature reader as discussed above, in a simple form of the system.
Fingerprint readers are well Known and well developed. For example, see U.S. Pat. No. 4,537,484 referenced above. Retina scanners are also known and effective for distinguishing between individuals and matching a known retina scan of a person, as discussed above. If a retina scanner is used in the system of the invention, the window 25 can have behind it a retina scanner. However, many individuals may find retina scanners objectionable.
An individual's facial photograph can be digitized and stored as encoded data carried on the key 16. The window 25 in FIG. 3 can have behind it a camera, such as a video camera, for producing a video image which can be scanned by associated electronics and compared with the image encoded on the key 16, to determine whether a close enough match exists.
If voice identification is used, a microphone can be included on the panel 28 shown in FIG. 3, indicated as grid lines 32 in FIG. 3.
It should be understood that ordinarily not all of the items 25, 30 and 32 will be included on the access control panel 28--they are illustrated primarily as alternatives.
When a keyholder approaches a high-security access control point such as exemplified in FIG. 3, he may not be required to actually use his key in a keyway (indicated at 34) of the door, gate, computer, safe, drawer, etc. Instead, the keyholder positions his key 16 in a position to be scanned for the encoded data (as by inserting it into a keyway such as shown at 26) and he inputs his personal identifying or authenticating feature, e.g. his actual fingerprint, to be compared with the data from the key, using the panel 28. If a match is found, access preferably is granted electrically (optionally other criteria may first be required as described below). Thus, if the access control point has a door 36 such as shown in the example of FIG. 3, the panel electronics can actuate an electric release 38 in the door jamb 40, or an electric strike 41 in the door 36. This enables the authenticated keyholder to merely pull or push the door 36 open, without rotation of any lock cylinder in the door.
However, in an embodiment of the invention the keyholder may also be required to use his key 16 in a keyway 34 in the door. For example, the door may include a deadbolt or catch (not shown) which cannot be released by any key within the possession of a certain class of personnel, but which will be released, allowing the door to open, by an electric door jamb release mechanism 38 or electric strike mechanism 41 controlled by the panel 28. In addition, a different mechanical strike or deadbolt 43 can be controlled by the mechanical lock cylinder 34, which the authenticated keyholder will be required to use in addition, when access has been granted electronically via the panel 28. This can also serve as mechanical backup security in the event the electronic system is shut off or malfunctions.
Alternatively, a keyway 34 can be provided in the door which will receive a different key, other than the key 16 in the possession of the keyholder. The special key for the keyway 34 can override the electronic system under certain conditions such as an emergency, but with special high-security keys for this keyway 34 only possessed by certain high-security personnel. In addition, preferably a record is made and sent to a central processor whenever the door is opened by such a special key, without authentication via the panel 28. This is discussed further below with reference to FIGS. 4 and 5.
As another alternative, the keyway 34 shown in the door 36 can fit the keyholder's key 16, but with the cylinder associated with keyway 34 normally disabled against unlocking the door in this way, thus normally requiring the panel 28 to release the door. The disabling mechanism for the key cylinder 34 can be electrically released, such as in times of emergency or certain times of day when high-security access control is not required. During these periods, access can be gained, e.g. the door 36 can be opened, merely using the mechanical key 16 and the keyway 34, in the conventional manner.
Such a cylinder's disabling mechanism can simply be a solenoid operated or otherwise electrically actuated pin internal to the door 36, which locks the cylinder 34 against rotation except when electrically released.
FIG. 3 shows an optional door or cover 25a (dashed lines) which can be included to cover the reader window 25 when not in use. The cover 25a can be slidable and solenoid operated--normally closed but openable automatically when a key is inserted in the keyway 26. The cover can comprise a pair of doors which slide in and out from left and right or top and bottom. In a system with date/time access control the opening of the cover 25a can be delayed until after a signal is received from the central processor authorizing entry to the particular personnel number or key number at the particular time.
In preferred embodiments of the overall system of the invention, once the keyholder has gained access at the access control point 12 shown in FIG. 3 (e.g. he has opened the door 36 and entered), the keyholder may encounter additional high-security access points 12, or he may simply encounter lower security access points 14 (FIG. 1). These latter access points 14 will require only the mechanical key 16 with its configuration 19, without use of the encoded data. In this way, the single access item (the mechanical key) is used for several purposes within the system.
FIG. 1 shows that the high-security access control points 12 may include different levels of security. The highest security is illustrated at 12a, where a fingerprint verification reader 24 and a keyway for a key code reader 26 are both included; at 12b, only the keyway/key reader 26 is included, without fingerprint verification. At this type access control point, the key identification number or code is read from the key and sent to the processor unit 15, which will send back a signal to grant access only if the person associated with that key number is to be admitted at the particular date and time involved. This information is stored in memory at the processor 15.
Similarly, time/date control may be a part of the access decision at all or some high-security points 12a depending on the type of facility and whether differentiation is needed among personnel and as to dates and times of permitted access. Each user's key preferably includes the encoded key number or ID number which is read by the key reader. This is sent to the central processor 15, which determines whether access is restricted at this particular time, and sends back a signal to the panel 28 confirming or denying access. This decision, as well as the comparison, must be positive for access to be granted.
FIG. 4 is another schematic representation showing several access control points including a high-security access control point 12, in elevational section. Various components of the security panel 28 are shown, as well as connection to the central processor 15. As in FIG. 3, FIG. 4 shows the system with a fingerprint reader 42, behind the window 25, as one preferred embodiment; however, it should be understood that other types of personal authentication biometric feature reading devices may be substituted for the fingerprint reader 42, as mentioned above.
As indicated in FIG. 4, and also in reference to FIG. 5, the control panel includes a key scanner or reader 44 for reading the encoded data on the key. This may be associated with a keyway 26 as illustrated in FIG. 3, although the encoded data be alternatively be on the head of the key (or on a card key, as discussed above), with the key simply placed up adjacent to the key scanner 44.
If a keyway is included, the encoded data (which may be optically encoded) may be scanned using the movement of the key in entering the keyway. This is shown schematically in FIG. 6. Data on the key, which may be encoded in the recess 20, is scanned by a beam such as a focused laser beam 44a emanating from a laser diode 44b and focused by focusing optics 44c. As the key 16 is mushed into the slot or keyway 26, the encoded information is moved mast the beam 44a and this movement produces a scan, eliminating the need for a beam scanner. A reflection signal from the encoded information returns and is reflected by a beam splitter mirror 44d and another mirror 44e to a photodetector 44f. The electrical voltage signal from the detector 44f is fed to a special data decode processor 44g and the decoded signal is sent to the local processor 46. Alternatively, the raw signal from the detector 44f can go directly to the local processor 46, provided with decode software.
FIGS. 4 and 5 also show schematically an electric release or electric strike 45 in the door jamb or door, to be activated by the panel 28 when a keyholder is authenticated and granted access.
A small local processor 46 at the panel 28 receives inputs from the electronic key scanner 44 and from the fingerprint reader 42, with the scanned fingerprint preferably digitized in the manner the encoded data is digitized. The processor 46 makes a comparison to determine whether the live fingerprint just scanned is close enough to the fingerprint data as digitized in the encoded data to constitute a match, within preset criteria, and if so, a preliminary decision is made to grant access. If time/date control is not included the electric release or electric strike may be activated at this point to admit the person.
At the same time, as shown in FIGS. 4 and 5, the key scanner or reader 44 preferably reads an encoded identifying number (or other ID code) from the data carried by the key, and this information is sent to the central processor 15. It can either go into the local processor and from there to the central processor in a report, or directly to the central processor as shown in FIG. 5, to be there correlated with an authentication report as discussed below.
If date/time access control is desired, this ID information is used by the central processor 15 to determine (via a database) whether access should be granted at this time. As indicated in FIG. 5, and in the flow chart of FIG. 8, both "yes" decisions are required in order for the electric release or strike 45 to be activated. The central processor looks up the ID number and checks whether that ID number should be permitted entry at the particular date and time of attempted entry.
The ID information is also used to make a record of the transaction in the central processor 15. A transaction record or report 47 (FIGS. 5 and 8), sent to the central processor 15, can comprise only the access decision, i.e. yes or no, from the authentication comparison. A signal carrying this information can be sent to the central processor with a simple two-conductor cord, indicated by a line 48 shown in FIGS. 4 and 5. In the central processor 15 this report is correlated the personnel or key identifying number or code (ID number), which has been received almost simultaneously.
The flow chart of FIG. 8 outlines functions carried out in a preferred embodiment of the system of the invention. These functions are illustrated without regard to which processor or other element is used to perform each function. The flow chart does not need further explanation, beyond the description on the chart and the description herein.
FIG. 4 also indicates a form of switch 50, such as a mechanical limit switch or photoelectric sensor, which optionally may be actuated every time the door or gate or drawer, etc. 36 is opened. This information can be sent to the central processor (via line 52, which can be the same conductor wire as represented by the line 48), and it will normally match a positive access decision as described above. If the door is ever opened in the absence of a positive access decision, a report of such occurrence can be made by the central processor (it can be printed out via the printer 18). An audible alarm and/or indicator light can also be activated, if desired.
FIG. 7 shows schematically a variation of what has been described in the other drawing figures. In FIG. 7 an access control system 70 in accordance with the invention includes a large plurality of high-security access control points 72 (labeled in FIG. 7 as 72a, 72b and 72c). Each of these access control points 72 may be similar in most respects to the high-security access control points 12 shown in FIGS. 3, 4 and 5.
However, in the embodiment shown in FIG. 7 these access control points 72 are grouped into an "A" group, a "B" group and a C group. The A group of access control points 72a are each connected to a processor A, with the B group connected to a processor B and the C group connected to a processor C. The access control points within a group are Physically located close to one another, so that they can easily be connected, as by a two-conductor wire, to the processor for the group.
Each of the processors A, B and C serves the function of the small processor 46, but is of somewhat larger capacity so that a group of access control points can be served.
The system 70 also includes a central processor 15 such as described above with reference to FIGS. 1, 4 and 5. With the group processors being of larger capacity than the local processors 46 in the earlier embodiment, the processor 15 may be used to program the group processors A, B and C to handle some functions which otherwise would have been performed by the main processor 15. This can include the date/time control information discussed above, which can also be used to exclude certain personnel (by ID number or key number) who should no longer have access, such as discharged employees.
The processor 15 is also used, as in the previous embodiment, for maintaining a database and for receiving reports from the processors A, B and C and for itself generating reports. The printer 18 may be included, as above, as well as a display monitor 74.
FIG. 9 is a simple block diagram illustrating the interconnection of the system of the invention with an employee time management system, as for time and payroll management of hourly employees. FIG. 9 shows that an employee on beginning a work shift will approach one or more high-security entry doors (which can include non-authenticating access points 12b shown in FIG. 1). The employee inserts his key, which is read at least for the employee number or ID number (block 80), and preferably also is read for the authenticating feature as indicated in the figure. After the central processor checks a database for time/date control (block 82), and the employee is approved to enter at this time, and assuming keyholder authentication is positive, if necessary, as in the block 84, the door is released and access is permitted (block 86). This causes a report 88 to be created, indicating the date and time of entry and the employee identity. The report is sent to time management and payroll 90, which may be operated by the central processor.
When the same employee exits, at the end of a shift or for a meal break, he again inserts his key, but into a key reader at the inside of the door, which signifies that he is exiting. This is indicated in the block 92. Keyholder authentication (block 95) preferably is again required to assure that the proper employee is checking himself out. The employee removes his key and exits (block 94). The opening of the door itself does not require keyholder authentication or even key insertion, but properly taking these steps is in the employee's interest for payroll records. A report 96 is generated, which goes to time management and payroll 90. The record of the employee's entry and exit times enables the compilation of a weekly (or biweekly, monthly, etc.) time report and the automatic printing of checks for the employee (block 98).
FIGS. 10 and 11 show card type access control devices encompassed by the invention. The credit card type key 16a of FIG. 10 was discussed above. In FIG. 11 a different type of card 100 is shown, not necessarily containing any locks accessing feature such as the feature 21 shown in FIG. 10. The card 100 serves as an ID card or security pass, preferably with a photograph 102 of the intended bearer. It also serves as an access control device, having a biometric feature (e.g. fingerprint) encoded in a strip of encoded data 23. Thus, the card 100 is used by the bearer for accessing high-security access points in the manner described with reference to FIGS. 1 and 3 through 9, while also serving as a security pass visual inception. A principal difference is that the card 100 may not be capable of directly accessing any lock.
The above described preferred embodiments are intended to illustrate the principles of the invention, but not to limit its scope. Other embodiments and variations to these preferred embodiments will be apparent to those skilled in the art and may be made without departing from the spirit and scope of the invention as defined in the following claims. | An access control system combines card type keys or mechanical keys and lock cylinders with keyholder authentication, so that only the authorized keyholder or keyholders can use a key at an access control point. The access control point can be a door, gate, drawer, safe, safety deposit box, computer terminal or other situation wherein high security is desirable. In a preferred embodiment, the access control system includes a series of mechanical keys (or card type keys) having encoded data stored on the bottom edges of the keys. The encoded data may be in the form of a bar code or optical data storage, either directly formed onto the key or on a strip of plastic or other material bearing the encoded data, secured to the key. In one form of the invention, user authentication involves a biometric feature such as a fingerprint of the intended keyholder. The fingerprint is digitized, encoded and placed on the bottom edge of the mechanical key for that intended keyholder, preferably along with an encoded keyholder identifying number. An authentication reader at a high security access control point includes a keyway with a reader for the encoded data representing the encoded fingerprint, and also a fingerprint reader for reading the user's fingerprint at each instance of attempted entry. Comparison of the attempted user's fingerprint with the stored fingerprint is preferably made directly at the access control point, so that only the access decision and a keyholder identifying code need to be sent to a central processor. | 39,257 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No. 14/068,626 which claims the benefit of U.S. Provisional Application No. 61/720,894, filed Oct. 31, 2012 and U.S. Provisional Application No. 61/720,931, filed Oct. 31, 2012, all of which are herein incorporated by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to a drive mechanism, and more particularly to a drive mechanism for an electric toothbrush.
BACKGROUND OF THE INVENTION
[0003] After a certain amount of use, the brush heads on electric toothbrushes often wear out and need to be replaced. A drive mechanism that is efficient and includes parts that are easily connectable between the new brushing attachment and handle is desirable.
SUMMARY OF THE PREFERRED EMBODIMENTS
[0004] The invention generally is a drive interface between a powered toothbrush handle that includes a battery, motor, and gear train that rotates a drive shaft located at an attachment interface, such as the attachment mechanism disclosed and claimed in pending U.S. Non-provisional patent application Ser. No. 14/068,733, filed on Oct. 31, 2013 which is incorporated herein by reference for all purposes, to power a removable brushing attachment. The drive interface includes features that help provide proper alignment during connection and drive torque during operation.
[0005] In accordance with a first aspect of the present invention there is provided a toothbrush that includes a brushing attachment and a handle. The brushing attachment includes a main body portion with a hollow neck with an attachment opening and a head with a cleaning member opening, a drive shaft positioned in the neck, a cleaning member drive mechanism matingly engaged with gearing on the drive shaft, and a cleaning member extending through the cleaning member opening in the head and operatively associated with the cleaning member drive mechanism. The drive shaft includes a spline drive on one end and the gearing on the opposite end and is positioned adjacent the attachment opening in the neck. The handle includes a main body portion that houses a motor, and a brushing attachment connection receiver extending upwardly from the main body portion that is at least partially received in the attachment opening in the brushing attachment. The brushing attachment connection receiver includes a recess defined therein that receives a drive hub therein. The drive hub includes a grooved recess defined therein that receives the spline drive. In a preferred embodiment, the grooved recess includes a straight section and an incline section, and the straight section has smaller outer diameter than the outer diameter of the incline section. Preferably, the grooved recess includes at least one drive groove having an inner surface and at least one guide groove having an inner surface, and there is clearance between the spline positioned in the guide groove and the inner surface of the guide groove. Put another way, the guide groove is larger in volume than the drive groove. In an embodiment, the grooved recess includes a plurality of alternating drive grooves and guide grooves.
[0006] In accordance with another aspect of the present invention, there is provided a brushing attachment for a toothbrush that includes a main body portion, drive shaft, cleaning member drive mechanism, and a cleaning member. The main body portion includes a hollow neck and a head, and the neck includes an attachment opening and the head includes a cleaning member opening. The drive shaft is positioned in the neck and includes a spline drive on one end and gearing on the opposite end. The spline drive is positioned adjacent the attachment opening in the neck. The cleaning member drive mechanism is matingly engaged with the gearing on the drive shaft, and the cleaning member extends through the cleaning member opening in the head and is operatively associated with the cleaning member drive mechanism. In use, motivating rotational force imparted to the spline drive is translated from the drive shaft to the cleaning member drive mechanism and to the cleaning member such that the cleaning member rotates. In a preferred embodiment, the spline drive includes a plurality of splines that each have an inclined surface on the distal end thereof. Preferably, each of the six splines includes two opposing longitudinally extending surfaces that taper toward the distal end.
[0007] The invention, together with additional features and advantages thereof, may be best understood by reference to the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] FIG. 1 is a side elevational view of an electric toothbrush having a handle and brushing attachment removably connected to one another in accordance with a preferred embodiment of the present invention;
[0009] FIG. 2 is an exploded view of the electric toothbrush of FIG. 1 , showing the drive hub and drive shaft;
[0010] FIG. 3A is a perspective view of the drive shaft;
[0011] FIG. 3B is a bottom plan view of the drive shaft;
[0012] FIG. 4A is a perspective view of the drive hub;
[0013] FIG. 4B is a top plan view of the drive hub;
[0014] FIG. 4C is an cross-sectional view of the drive hub taken along line 4 C- 4 C of FIG. 4B ;
[0015] FIG. 4D is an cross-sectional view of the drive hub taken along line 4 D- 4 D of FIG. 4C ;
[0016] FIG. 5 is a side elevational view of the drive shaft inserted into the drive hub, with the drive hub shown in cross-section;
[0017] FIG. 6 is a cross-sectional view taken along line 6 - 6 of FIG. 5 ; and
[0018] FIG. 7 is a cross-sectional view of the brushing attachment with the internal components in elevation.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] The following description and drawings are illustrative and are not to be construed as limiting. Numerous specific details are described to provide a thorough understanding of the disclosure. However, in certain instances, well-known or conventional details are not described in order to avoid obscuring the description. References to one or an embodiment in the present disclosure can be, but not necessarily are references to the same embodiment; and, such references mean at least one of the embodiments.
[0020] Reference in this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the-disclosure. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. Moreover, various features are described which may be exhibited by some embodiments and not by others. Similarly, various requirements are described which may be requirements for some embodiments but not other embodiments.
[0021] The terms used in this specification generally have their ordinary meanings in the art, within the context of the disclosure, and in the specific context where each term is used. Certain terms that are used to describe the disclosure are discussed below, or elsewhere in the specification, to provide additional guidance to the practitioner regarding the description of the disclosure. For convenience, certain terms may be highlighted, for example using italics and/or quotation marks: The use of highlighting has no influence on the scope and meaning of a term; the scope and meaning of a term is the same, in the same context, whether or not it is highlighted. It will be appreciated that the same thing can be said in more than one way.
[0022] Consequently, alternative language and synonyms may be used for any one or more of the terms discussed herein. Nor is any special significance to be placed upon whether or not a term is elaborated or discussed herein. Synonyms for certain terms are provided. A recital of one or more synonyms does not exclude the use of other synonyms. The use of examples anywhere in this specification including examples of any terms discussed herein is illustrative only, and is not intended to further limit the scope and meaning of the disclosure or of any exemplified term. Likewise, the disclosure is not limited to various embodiments given in this specification.
[0023] Without intent to further limit the scope of the disclosure, examples of instruments, apparatus, methods and their related results according to the embodiments of the present disclosure are given below. Note that titles or subtitles may be used in the examples for convenience of a reader, which in no way should limit the scope of the disclosure. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. In the case of conflict, the present document, including definitions, will control.
[0024] It will be appreciated that terms such as “front,” “back,” “upper,” “lower,” “side,” “short,” “long,” “up,” “down,” and “below” used herein are merely for ease of description and refer to the orientation of the components as shown in the figures. It should be understood that any orientation of the components described herein is within the scope of the present invention.
[0025] Referring now to the drawings, which are for purposes of illustrating the present invention and not for purposes of limiting the same, FIGS. 1-6 show an electric toothbrush 10 having a handle 12 and a brushing attachment 14 and that includes a drive mechanism or interface 16 . It will be understood that the electrical components of the handle 12 , (e.g., the motor 17 , battery, etc.) and the components for transmitting motion (e.g., rotational motion) to the drive mechanism 16 are known. Therefore, a discussion of these components will be omitted. Furthermore, any type of attachment mechanism for securing the brushing attachment 14 to the handle 12 is within the scope of the present invention and, therefore, a description herein will be omitted. For example, the attachment mechanism taught in U.S. Pat. No. 8,196,246, the entirety of which is incorporated herein be reference, can be used.
[0026] As shown in FIGS. 2 and 5 , the drive mechanism 16 generally includes a drive hub 18 that is received in a recess 20 defined in a brushing attachment connection receiver 22 that extends from the main body portion 21 of the handle 12 and a drive shaft 24 that is housed in a neck 26 of the brushing attachment 14 . A bushing can be used to position or secure drive shaft 24 within neck 26 . However, this is not a limitation on the present invention.
[0027] With reference to FIGS. 2 and 7 , in a preferred embodiment, brushing attachment 14 includes a main body portion 25 (comprising neck 26 and a head 28 ) and cleaning member 30 (e.g., bristles). The neck 26 includes an attachment opening 26 a and the head 28 includes a cleaning member opening 28 a. It will be appreciated by those skilled in the art, that brushing attachment 14 can include brushing surfaces other than the bristles, such as massagers, flossers or other tooth cleaning technology known in the art (these are all referred to herein generally as “cleaning members”). Internally, the brushing attachment 14 includes gearing 32 or other energy translation mechanism for translating the rotational energy through the 90 degree bend from the drive shaft 24 to the cleaning member 30 .
[0028] As shown in FIGS. 3A and 3B , in a preferred embodiment, drive shaft 24 is a unitary structure that includes a spline drive 34 comprising a series of splines 34 a on one end thereof, and gearing 32 on the other end thereof In another embodiment, the drive shaft 24 can be constructed of separate, non-unitary parts. As shown in FIG. 7 , the gearing 32 on the end of the drive shaft 24 mates with the gearing 32 on a cleaning member drive mechanism 33 that is positioned in the head 28 . Gearing for translating the rotation of the drive shaft 24 to the cleaning member drive mechanism 33 (through the 90 degree bend) and ultimately the cleaning member 30 is known. Any type of gearing or the like is within the scope of the present invention. Furthermore, any type of cleaning member drive mechanism 33 and attachment to the cleaning member 30 is within the scope of the present invention.
[0029] As shown in FIGS. 4A-4D , in a preferred embodiment, drive hub 18 includes a main body portion 36 that is received in recess 20 , a rim 38 that seats on or is adjacent to the top surface of brushing attachment connection receiver 22 , a lower recess 40 for receiving rotational energy from the motor (e.g., via a knurled shaft), and an upper or grooved recess 42 that includes a series of grooves 44 that matingly engage the spline drive 34 of the drive shaft 24 . In a preferred embodiment, the grooves 44 each include a straight portion 44 a and a lead in or incline portion 44 b. The straight portion 44 a interfaces with the splines 34 a to provide the interface to facilitate the transfer of the rotational motivation generally from the handle 12 to the brushing attachment 14 , and more specifically, from the drive hub 18 to the drive shaft 24 . The incline portion 44 b helps facilitate the insertion of the spline drive 34 into the upper recess 42 . As shown in FIG. 4A , in a preferred embodiment, the incline portion 44 b of the grooves 44 includes a circumferential incline surface 46 a and two non-circumferential incline surfaces 46 b.
[0030] The plurality of grooves 44 together form, within the upper recess 42 , a straight section 42 a and an incline section 42 b. As shown in FIGS. 4B and 6 , the incline section 42 b has a greater outer diameter OD 1 than the outer diameter of the spline drive 34 OD 2 (measured at the tip of the individual splines 34 a ) and a greater outer diameter OD 1 than the outer diameter of the straight section 42 a OD 3 . The larger diameter and incline section 42 b makes it easier to align the drive shaft 24 with the straight section 42 a of upper recess 42 when placing a brushing attachment 14 on the handle 12 . In a preferred embodiment, the splines 34 a each include an inclined surface 34 b on the distal end 34 c thereof, which further facilitates alignment of the drive shaft 24 and drive hub 18 . As is best shown in FIG. 5 , the splines 34 a each include two opposing longitudinally extending surfaces 34 d that taper toward the distal end 34 c thereof The inclined and tapered surfaces all help facilitate mating of the spline drive 34 with the grooved opening 42 of the drive hub 18 . In another embodiment, the tapered surfaces 34 d and the inclined surfaces 34 b can be omitted.
[0031] In a preferred embodiment, as is shown best in FIG. 4B , within the series of grooves 44 , the drive hub 18 and upper recess 42 also include drive grooves 44 c and guide grooves 44 d. The guide grooves 44 d are sized larger than the splines 34 a and help provide proper alignment of the splines 34 a during attachment of the brushing attachment 14 . The clearance between the surfaces of splines 34 a and the inner surfaces of guide grooves 44 d are shown in FIG. 6 . The drive grooves 44 c are sized to snugly receive the splines 34 a and provide little clearance. In use, the drive surface of drive grooves 44 c contact the splines 34 a positioned within drive grooves 44 c to rotate drive shaft 24 . In a preferred embodiment, the drive grooves 44 c and the guide grooves 44 d alternate. However, this is not a limitation on the present invention. In the exemplary embodiment shown in the figures, the drive hub 18 includes three drive grooves 44 c and three guide grooves 44 d. However, this is not a limitation on the present invention and any number of drive grooves 44 c and guide grooves 44 d can be used.
[0032] In use, a new brushing attachment 14 is placed onto the brushing attachment connection receiver 22 such that the spline drive 34 is received into upper recess 42 . As the spline drive 34 enters the incline section 42 b, if the drive shaft 24 is misaligned, as a result of the incline, the spline drive 34 will be guided inwardly until the axis of the drive shaft 24 is generally axial with the axis of the drive hub 18 and the spline drive 34 will enter the straight section 42 a of upper recess 42 . The individual splines 34 a each enter a corresponding drive groove 44 c or guide groove 44 d. The attachment mechanism between the handle 12 and brushing attachment 14 is attached and the toothbrush is now ready for use. When the toothbrush 10 is used, motivating rotational force is transferred from the motor to the drive hub 18 , which, as a result of the interaction of splines 34 a and drive grooves 44 c, imparts motivating rotational force to drive shaft 24 . As a result of gearing 32 , the motivating rotational force is translated 90 degrees from the drive shaft 24 and to cleaning member 30 , for teeth cleaning.
[0033] Unless the context clearly requires otherwise, throughout the description and the claims, the words “comprise,” “comprising,” and the like are to be construed in an inclusive sense, as opposed to an exclusive or exhaustive sense; that is to say, in the sense of “including, but not limited to.” As used herein, the terms “connected,” “coupled,” or any variant thereof, means any connection or coupling, either direct or indirect, between two or more elements; the coupling of connection between the elements can be physical, logical, or a combination thereof Additionally, the words “herein,” “above,” “below,” and words of similar import, when used in this application, shall refer to this application as a whole and not to any particular portions of this application. Where the context permits, words in the above Detailed Description of the Preferred Embodiments using the singular or plural number may also include the plural or singular number respectively. The word “or” in reference to a list of two or more items, covers all of the following interpretations of the word: any of the items in the list, all of the items in the list, and any combination of the items in the list.
[0034] The above-detailed description of embodiments of the disclosure is not intended to be exhaustive or to limit the teachings to the precise form disclosed above. While specific embodiments of and examples for the disclosure are described above for illustrative purposes, various equivalent modifications are possible within the scope of the disclosure, as those skilled in the relevant art will recognize. Further any specific numbers noted herein are only examples: alternative implementations may employ differing values or ranges.
[0035] Any patents and applications and other references noted above, including any that may be listed in accompanying filing papers, are incorporated herein by reference in their entirety. Aspects of the disclosure can be modified, if necessary, to employ the systems, functions, and concepts of the various references described above to provide yet further embodiments of the disclosure.
[0036] Accordingly, although exemplary embodiments of the invention have been shown and described, it is to be understood that all the terms used herein are descriptive rather than limiting, and that many changes, modifications, and substitutions may be made by one having ordinary skill in the art without departing from the spirit and scope of the invention. | A toothbrush that includes a brushing attachment and a handle. The brushing attachment includes a main body portion with a hollow neck having an attachment opening and a head with a cleaning member opening, a drive shaft positioned in the neck, a cleaning member drive mechanism matingly engaged with gearing on the drive shaft, and a cleaning member extending through the cleaning member opening in the head and operatively associated with the cleaning member drive mechanism. The drive shaft includes a spline drive on one end and gearing on the opposite end. The handle includes a main body portion with a brushing attachment connection receiver that is at least partially received in the attachment opening. The brushing attachment connection receiver includes a recess defined therein that receives a drive hub with a grooved recess defined therein that receives the spline drive. | 20,549 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan application serial no. 94104990, filed on Feb. 21, 2005. All disclosure of the Taiwan application is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of Invention
[0003] The present invention relates to a mobile storage device, more specifically, to a stackable mobile storage device.
[0004] 2. Description of Related Art
[0005] Nowadays is information and multi-media age, a vast amount of information is digitized before being processed. Large size magnetic disks were used in the past, however, affected by magnetization effect, so that the magnetic disks were gradually eliminated due to its insufficient capacity, and small storage memories with larger capacity. A smaller storage medium with larger storage capacity and smaller volume has been introduced instead. Memory card, mobile drive (or walk drive) and micro hard drive in most common use have been developed based on the flash memory technology. In addition, these new type drives have advantages of easy carrying and convenient access.
[0006] Generally speaking, in the fabrication of the mobile drive, the mobile drive can mutually supports USB1.1 interface and USB2.0 interface to transport vast amount of data, so as to be compatible to a computer and its peripherals. And, the mobile drive requires no reading device (such as card reader), and features in plug-and-play. Moreover, since the capacity of the mobile drive is getting larger and larger, and it can store up to hundreds of compressed songs (such as MP3 music, etc.). Therefore, it can be very conveniently used as a walkman or pen recorder.
[0007] Remarkably, the capacity of the conventional single mobile drive is fixed, and no extension slot is designed on the drive. Thus, it is impossible to expand the capacity of the mobile drive when the user finds that the capacity is insufficient. As a result, one has to partially delete or completely erase the data on the original mobile drive, or transfer the data to a computer hard drive, so that new data can be stored on the mobile drive. This is very inconvenient. If the size of the new data is larger than the capacity of the mobile drive, the user has to use an alternative method or purchase a drive with lager capacity to solve this issue. However this will increase the cost. Therefore, the conventional single-capacity mobile drive is not convenient in various uses, and the capacity of each mobile drive can't be shared, thus its usability is affected.
SUMMARY OF THE INVENTION
[0008] The object of the present invention is to provide a stackable mobile storage device which can expand the capacity of the mobile drive.
[0009] Another object of the present invention is to provide a control circuit by which the capacity of each mobile drive can be aggregated into a larger capacity to store more data conveniently.
[0010] The present invention provides a stackable mobile storage device including a first mobile drive, at least one second mobile drive and a detachable module. The first mobile drive includes a transmitting interface and a control unit, and the second mobile drive is stacked on the first mobile drive. Wherein, the first mobile drive has a first memory, while the second mobile drive has a second memory, and the capacity of the second memory can be added to the capacity of the first memory through a switching unit and is enabled by the control unit. In addition, the detachable module is coupled between the first and second mobile drives.
[0011] The present invention provides a control circuit which is suitable for using in a mobile storage device with a plurality of mobile drives. Each of the mobile drives has a memory, a control unit, a detachable module and a switching unit. Wherein, the detachable module has a male connector and a female connector, and the mobile drives are electrically coupled to each others by a manner of the combination of the male and the female connectors. In addition, the switching unit has a first switch, a second switch and a third switch, wherein the first switch is coupled between the control unit and the memory, and the second switch is coupled between the male connector and the memory, and the third switch is coupled between the female connector and the memory, so that the memory of each mobile drive is enabled by the control unit.
[0012] The present invention further provides a capacity expandable mobile drive which includes a base block, a transmitting interface, at least one connector and a switching unit. The base block includes a control unit and a memory, wherein the control unit is to control the reading and the writing operations on the memory. Moreover, the transmitting interface can be protruded out or hidden within the base block, and be electrically connected with the control unit. In addition, the connector is implemented on the base block to connect at least one second mobile drive which has a second memory. Furthermore, the switching unit has a plurality of switches wherein one of these switches is coupled between the control unit and the memory, and another one of these switches is coupled between the connector and the memory. As a result, the second memory of the second mobile drive can be enabled through the control unit.
[0013] According to the embodiment of the present invention, the above control unit for example includes a control chip and a circuit board, and the control chip is electrically connected to a transmitting interface through the circuit board. In addition, the transmitting interface is, for example, a universal serial bus (USB) interface. Moreover, the switching unit is, for example, an electronic three-way switch or a mechanical three-way switch.
[0014] The detachable module and the switching unit coupled between two mobile drives are used in the present invention to form a stackable mobile storage device with expandable capacity and its control circuit. Therefore, a single mobile drive can be used individually, and when a plurality of mobile drives are stacked together, the memories can be shared so as to increase the selectivity and manipulability of the mobile drive on using.
[0015] These and other exemplary embodiments, features, aspects, and advantages of the present invention will be described and become more apparent from the detailed description of exemplary embodiments when reading in conjunction with accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] FIG. 1A - FIG. 1B schematically illustrate the outer appearance and internal block diagram of a stackable mobile storage device, according to an embodiment of the present invention.
[0017] FIG. 2 schematically illustrates the block diagram of the internal equivalent circuit of the storage device of FIG. 1A .
[0018] FIG. 3 and FIG. 4 respectively schematically illustrate the outer appearance and the block diagram of the internal equivalent circuit of a stackable mobile storage device, according to an embodiment of the present invention.
[0019] FIG. 5 schematically illustrates the disassembling and assembling diagram of a stackable mobile storage device, according to another embodiment of the present invention.
[0020] FIG. 6 schematically illustrates the block diagram of the internal equivalent circuit of the stackable flash storage device of FIG. 5 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0021] FIG. 1A - FIG. 1B schematically illustrate the outer appearance and internal block diagram of a stackable storage device, according to an embodiment of the present invention. And FIG. 2 schematically illustrates a block diagram of the internal equivalent circuit of the storage device of FIG. 1A . Referring to FIGS. 1A-1B , first, the stackable storage device 100 for example includes a base block 110 , a transmitting interface 120 , a male connector 132 , a female connector 134 and a switching unit 140 . Wherein, the base block 110 has a built-in control unit 112 , such as control a chip 114 , a circuit board 116 and the related parts thereof (not shown) etc. The control chip 114 can be electrically connected with the transmitting interface 120 through the circuit board 116 as shown in FIG. 1B . A usual transmitting interface 120 is, for example, a universal serial bus (USB) interface, an IEEE 1394 transmitting interface or other high speed transmitting interface, and preferably, the transmitting interface satisfying the specification of USB1.1 and USB2.0. In the present embodiment, although the transmitting interface 120 is protruded out of the base block 110 , it can also be a retractable design (not shown) within the base block 110 . The transmitting interface 120 can be electrically connected to the control unit 112 through a flat cable 136 , so that the transmitting interface 120 can be hidden in the base block 110 .
[0022] With referring to FIG. 1B , the base block 110 further includes a memory 118 inside, which includes for example a flash memory or other types of high capacity storage medium, implemented on the circuit board 116 . The control chip 114 can access data on the memory 118 . Remarkably, the switching unit 140 is implemented on the circuit board 116 . In the equivalent circuit shown in FIG. 2 , a switching unit 140 including a plurality of switches 141 - 143 or a single three-way switch (shown in FIG. 1A ) is implemented between the control chip 114 and the memory 118 to switch the master/slave property of the storage device. When the storage device 100 is used individually, just by switching the switching unit 140 to the master connection end (close the switch 140 in the middle, and leave the upper and lower switches 141 and 143 open), the mobile drive can serve as a regular mobile drive. Moreover, to use a plurality of storage devices 100 , just by combining the male connector 132 and the female connector 134 for switching its storage device to slave connection end (leaving the switch 142 in the middle open, and closing the upper and lower switches 141 and 143 respectively), the mobile drive can then serve as an expanded mobile drive to expand the capacity of the memory 118 .
[0023] With referring to FIG. 3 and FIG. 4 , both respectively show the diagram of the outer appearance and the block diagram of the internal equivalent circuit of a stackable mobile storage device of an embodiment of the present invention. The stackable mobile storage device 200 for example includes a first mobile drive 210 , at least one second mobile drive 220 and a detachable module 230 . The structure and function of the first mobile drive 210 are the same as those of the second mobile drive 220 . Inside the base block, 212 , 222 , both have control chips 214 , 224 and memories 216 and 226 , respectively. The difference is that when the first mobile drive 210 serves as the mobile drive of the master control end, the switch 218 in the middle is electrically coupled between the control chip 214 and the memory 216 , and leaves the circuit of upper and lower switches open. The second mobile drive 220 can only open the circuit of the middle and upper switches, and close the circuit of the lower switch 228 to connect the memory 226 and the corresponding female connector 234 , so that the second mobile drive serves as a mobile drive with an expanded capacity. In addition, the first and the second mobile drives 210 and 220 can be stacked on top of each other through a detachable module 230 that combines the male connector 232 to the female connector 234 . Specifically, the memory 226 of the second mobile drive 220 can be enabled by the control of the control chip 214 to store data.
[0024] In the above embodiment, the transmitting interface (not shown) can be hidden within the base block 222 to avoid hindering the use of the transmitting interface 240 of the first mobile drive 210 when the second mobile drive 220 serves as the capacity expanding mobile drive. Moreover, if the second mobile drive 220 is used individually, the user can just conveniently set the transmitting interface (not shown) to protrude out of the base block 222 , thus enable the users to have various options of memory capacities without causing the insufficient memory problem.
[0025] In addition, with referring to the FIG. 5 and FIG. 6 , both illustrate the diagram of the outer appearance and the internal equivalent circuit about a stackable mobile storage device, with an embodiment of the present invention. The stackable mobile storage device 300 for example includes a first mobile drive 210 , at least a second mobile drive 220 , at least a third mobile drive 320 and two detachable modules 230 and 330 . The structure and function of the first mobile drive 210 and the second mobile drive are as described in the previous embodiment, and there are also a control chip 324 and a memory 326 inside the base block 322 of the third mobile drive 320 . Specifically, when the first and the second mobile drive 210 , 220 are stacked on top of each other through a detachable module 230 between them, the first and the third mobile drives 210 and 320 can also be stacked on top of each other through another detachable module 330 (the combination of the male connector 332 and the female connector 334 ). In addition, the middle and the lower switches of the third mobile drive 320 are off, and the upper switch between the memory 326 and the corresponding male connector 332 is conducted, so that the whole of drive serves as a capacity expanding mobile drive, thus the mobile drive can be used very conveniently.
[0026] Similarly, the memory 326 of the third mobile drive 320 can also be enabled through the control chip 214 in the first mobile drive 210 . Also and, the transmitting interface (not shown) can be hidden within the base block 322 to avoid hindering the use of the transmitting interface 240 in the first mobile drive 210 when the third mobile drive serves as a capacity expanding mobile drive. In addition, the transmitting interface (not shown) can be just protruded out of the base block 322 if the third mobile drive is used individually. The switch at the middle is conducted and the upper and lower switches are off. The reading and writing operations on the memory 326 are controlled by its own control unit 324 .
[0027] It can be understood from the above descriptions, since a detachable module and a switching unit are used in the present invention to connect two mobile drives, a stackable mobile storage device and its control circuit with expandable memory capacity are formed. Wherein, each of the mobile drives is equipped with at least one connector (e.g. a male connector or a female connector, or both) which is capable of expanding the capacity of the memory, so that the capacity of the memory can be aggregated into a larger capacity. Moreover, the switching unit can be an electronic three-way switch, a mechanical three-way switch or a plurality of switches in combination.
[0028] In summary, the stackable mobile storage device and the control unit thereof of the present invention have at least the advantages as follows:
[0029] (1) Each mobile drive can be used individually, and a plurality of mobile drives can also be stacked on top of each other to share the memory to increase the selectivity and manipulability of the mobile drive.
[0030] (2) The transmitting interface can be hidden within the base block to avoid hindering the use of the transmitting interface in the master control end of the mobile drive when the mobile drive serves as a capacity expanding mobile drive.
[0031] While the present invention has been particularly shown and described with referring to exemplary embodiments thereof, it will be understood by those of ordinary skill in the art that various changes in form and details may be made therein without departing from the spirit and scope of the present invention as defined by the following claims. | A stackable mobile storage device is provided, including a first mobile drive, at least a second mobile drive and a detachable module plugged between the first mobile drive and the second mobile drive to stack each other. The detachable module is composed of a male connector and a female connector. Especially, the second mobile drive is connected to a control unit of the first mobile drive by a switching unit when serving as a mobile drive for expanding capacity, to be enabled by the control of the first mobile drive. Therefore, the memory capacity of the second mobile drive can be added to the first mobile drive with more capacity to store more data. | 16,707 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims all benefits of Japanese Patent Application No. 2004-118856, filed on Apr. 14, 2004, in the Japanese Intellectual Property Office, and Korean Patent Application No. 2004-79209, filed on Oct. 5, 2004, in the Korean Intellectual Property Office, the disclosures of which are incorporated herein in their entirety by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a memory medium, and, more particularly, to a method of recording and/or reproducing information with respect to a hologram memory medium, in which the information is recorded as interference fringes by using an object beam and a reference beam.
[0004] 2. Related Art
[0005] Recently, a rewritable optical disk of a phase shift type or an optical magnetic type is widely used as an information recording medium. In order to increase the recording density of such an optical disk, reducing the diameter of a beam spot and the distance between adjacent tracks or adjacent bits is required.
[0006] Although the recording density of an optical disk has been increased, the recording density of such an optical disk is physically limited by a diffraction limit of a beam, because data is recorded on a surface. Accordingly, a three-dimensional multi-recording including a depth direction is required to increase the recording density of an optical disk.
[0007] Therefore, a hologram memory medium having a large capacity due to a three-dimensional multi-recording region and a high speed due to a two-dimensional recording/reproducing method has attracted public attention as a next generation of computer file memory. Such a hologram memory medium may be formed by inserting a recording layer, which is formed of a photopolymer, between two sheets of glass. In order to record data on such a hologram memory medium, an object beam corresponding to data to be recorded and a reference beam are irradiated to the hologram memory medium to form interference fringes or interference patterns of the object beam and the reference beam. In order to reproduce data from the hologram memory medium, the reference beam is irradiated to the interference fringes to extract optical data corresponding to the recorded data.
[0008] In addition, hologram memory media having a cube shape and a card shape are provided. For example, Japanese Laid-open Patent No. 2000-67204 discloses a card shaped hologram memory including multiple recording layers on which waveguides are recorded to increase a recording capacity.
[0009] However, when recording/reproducing data on/from such a hologram memory medium, data is recorded on or reproduced from a data recording/reproducing area (or data area) on the hologram memory medium in a horizontal direction along a reference line, also known as a recording route, as shown in FIG. 1 . At the end of the reference line, the recording or the reproducing is stopped to move to an adjacent reference line, and then the recording or the reproducing of data is repeated in the horizontal direction along the adjacent reference line. However, such a method stops the recording or the reproducing of data at the ends of the reference lines. As a result, the operation continuity cannot be secured. Furthermore, the control of a data recording/reproducing optical system becomes complicated.
SUMMARY OF THE INVENTION
[0010] Accordingly, the present invention advantageously provides methods of recording/reproducing information on/from a hologram memory medium in which a recording/reproducing optical system can be conveniently controlled to increase a recording capacity of the hologram memory medium.
[0011] According to an aspect of the present invention, a method of recording information on a card or rectangular shaped hologram memory medium, comprises sequentially recording information on a data recording/reproducing area of the card shaped hologram memory medium along a predetermined route, while maintaining a predetermined distance between stripes of information.
[0012] Accordingly, the information can be continuously recorded on the card shaped hologram memory medium. In addition, the information can be continuously reproduced without operating an optical system, such as an optical pickup, unnecessarily.
[0013] The predetermined route may be formed in a spiral shape that spans the entire data recording/reproducing area of the card shaped hologram memory medium. Since the predetermined route is formed in the spiral shape, the data recording/reproducing area of the card shaped hologram memory medium can be effectively used, and the information may be continuously recorded in the data recording/reproducing area of the card shaped hologram memory medium.
[0014] The information recorded in the data recording/reproducing area of the card shaped hologram memory medium may be sequentially recorded from a central portion to a circumference or periphery of the card shaped hologram memory medium or from the circumference or periphery to the central portion of the card shaped hologram memory medium.
[0015] Accordingly, the data recording/reproducing area of the card shaped hologram memory medium can be effectively used, while continuously recording the information without operating an optical system unnecessarily.
[0016] Alternatively, the predetermined route may be formed in a continuous zig-zag shape that spans the entire data recording/reproducing area of the card shaped hologram memory medium, by having a plurality of reference lines that are parallel to one another and connecting the ends of each reference lines with the start portions of the following reference lines.
[0017] The information recorded on the data recording/reproducing area of the card shaped hologram memory medium may be sequentially recorded from an opened end of a reference line to an opened end of another reference line.
[0018] Accordingly, the data recording/reproducing area of the card shaped hologram memory medium can be effectively used, while continuously recording the information without operating an optical system unnecessarily.
[0019] A recording shape adjacent to a portion of converting a recording direction is a curve. Accordingly, a servo following property of an optical system, such as an optical pickup, may be sufficiently secured even in a portion of converting the recording direction.
[0020] According to an aspect of the present invention, the information may be recorded utilizing a two-dimensional shift multi-recording method. Accordingly, a recording capacity of the card-shaped hologram memory medium may be increased. When the information is recorded utilizing a two-dimensional shift multi-recording method, the distance between the parallel reference lines, which are formed in a spiral shape, is the same as a shift amount of the two-dimensional shift multi-recording. Accordingly, the information may be continuously recorded on the card shaped hologram memory medium, while increasing a recording capacity of the card shaped hologram memory medium, and without operating an optical system unnecessarily.
[0021] The present invention is more specifically described in the following paragraphs by reference to the drawings attached only by way of example.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] A better understanding of the present invention will become apparent from the following detailed description of example embodiments and the claims when read in connection with the accompanying drawings, all forming a part of the disclosure of this invention. While the following written and illustrated disclosure focuses on disclosing example embodiments of the invention, it should be clearly understood that the same is by way of illustration and example only and that the invention is not limited thereto. The spirit and scope of the invention are limited only by the terms of the appended claims. The following represents brief descriptions of the drawings, wherein:
[0023] FIG. 1 illustrates a conventional method of recording information on a hologram memory medium useful in gaining a more thorough appreciation of the present invention;
[0024] FIG. 2 illustrates a method of recording/reproducing information on/from a data area of a card shaped hologram memory medium along a recording (reproducing) route in a spiral pattern according to a first embodiment of the present invention;
[0025] FIG. 3 illustrates an adjacent distance according to the first embodiment of the present invention;
[0026] FIG. 4 illustrates example interference fringes recorded in a spiral pattern according to the first embodiment of the present invention;
[0027] FIG. 5 illustrates a method of recording/reproducing information on/from a data area of a card shaped hologram memory medium along a recording (reproducing) route in a continuous zig-zag pattern according to a second embodiment of the present invention;
[0028] FIG. 6 illustrates an adjacent distance according to the second embodiment of the present invention;
[0029] FIG. 7 illustrates example interference fringes according to the second embodiment of the present invention;
[0030] FIG. 8 illustrates an example hologram memory medium according to an embodiment of the present invention;
[0031] FIG. 9 is a block diagram of an example information recording/reproducing apparatus according to an embodiment of the present invention;
[0032] FIG. 10 illustrates an example optical system according to an embodiment of the present invention; and
[0033] FIG. 11 is a flowchart illustrating a method of recording/reproducing information on/from a hologram memory medium according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE EMBODIMENTS
[0034] The present invention is applicable for use with all types of memory or computer-readable media, hologram memory media, data recording/reproducing apparatuses and computer systems implemented methods described according to various embodiments of the present invention. However, for the sake of simplicity, discussions will concentrate mainly on exemplary use of a hologram memory media having a card shape or a rectangular shape, although the scope of the present invention is not limited thereto.
[0035] Attention now is directed to the drawings and particularly to FIGS. 2 through 7 , in which hologram memory media having information recorded by methods of recording information such as video data, audio data, audio/visual (AV) data, computer files or meta information according to various embodiments of the present invention. Specifically, FIG. 2 illustrates a method of recording/reproducing information on/from a data area of a card shaped hologram memory medium along a recording (reproducing) route in a spiral or concentric pattern according to a first embodiment of the present invention. FIGS. 3-4 illustrate an example distance Ws between parallel reference lines established by an interference pattern which is a series of interference fringes that span the entire data area of the hologram memory medium, as shown in FIG. 2 . FIG. 5 illustrates another method of recording/reproducing information on/from a data area of a card shaped hologram memory medium along a recording (reproducing) route in a continuous zig-zag pattern according to a second embodiment of the present invention. FIGS. 6-7 illustrate an example distance Ws between parallel reference lines established by an interference pattern which is a series of interference fringes that span the entire data area of the hologram memory medium, as shown in FIG. 5 . FIG. 8 illustrates a sectional view of a hologram memory medium having servo information i.e., location determination information, recorded thereon which is arranged on a surface facing a surface having a data area.
[0036] In one example embodiment of the present invention, an interference pattern which is a series of interference fringes recorded on the hologram memory medium is formed in a spiral shape, as shown in FIGS. 2 through 4 . Such interference fringes are recorded on the hologram memory medium due to an interference between an object beam and a reference beam during a recording operation. As a result, information can be continuously recorded on or reproduced from the hologram memory medium, starting from a central portion extending to a circumference or periphery of the hologram memory medium, or vice versa, without interruption, i.e., stopping recording or reproducing at an end of a reference line, and restarting at a next, adjacent reference line. In another example embodiment of the present invention, an interference pattern of interference fringes is formed in a continuous zig-zag shape by connecting end portions of reference lines to start portions of following references lines, while arranging the reference lines in parallel to one another, as shown in FIGS. 5 through 7 .
[0037] Referring to FIG. 8 , a hologram memory medium 1 includes a substrate 2 , a hologram recording layer 3 , a total reflection layer 4 , a protective layer 5 , a coat layer (not shown), an adherence layer (not shown), and a substrate 6 having pits 7 in a concave shape or a convex shape. As shown in FIG. 8 , the substrates 2 and 6 serve as bases of the hologram memory medium 1 . The hologram recording layer 3 is formed of a photosensitive material, for example, a photo polymer, a photorefractive crystal or any other material having a high recording/reproducing efficiency and resolution. Such a material should allow for repeated recording and erasing of data without causing a deterioration of the high recording/reproducing efficiency and resolution characteristics. Information of an object beam is recorded as interference fringes on the hologram recording layer 3 by irradiating the object beam and a reference beam to the same location on the hologram memory medium 1 .
[0038] The total reflection layer 4 reflects the object beam and the reference beam that are irradiated to the hologram recording layer 3 to prevent the transmission of the object beam and the reference beam to a surface facing a surface having a data recording/reproducing area. The protective layer 5 physically protects servo information, in other words, the pits 7 , in a concave shape or a convex shape formed on the substrate 6 from the outside.
[0039] The pits 7 include servo information of an optical system, such as an optical pickup, which records or reproduces information. Accordingly, the servo information can be optically read from the substrate 6 of the hologram memory medium 1 so as to properly control the location of the optical system, i.e., the irradiation location of the object beam and the reference beam from the optical system.
[0040] The pit row shape is symmetrical with the recording shape of the interference fringes (interference stripes), which are recorded on the hologram memory medium. For example, when the interference fringes are formed in a spiral shape, the pit row is formed in a spiral shape symmetrical with the spiral shape of the interference stripes.
[0041] Referring to FIGS. 3 and 6 , the distance W S between the parallel reference lines is applied to a two-dimensional multi-recording method. Therefore, the distance W s may be the same as a shift amount of the two-dimensional multi-recording method. Accordingly, the distance between the pit rows is the same of the distance WS between the reference lines. The examples of the interference stripes, which are recorded by the two-dimensional shift multi-recording method, are shown in FIGS. 4 and 7 .
[0042] In addition, recording information corresponding to table of content (TOC) data of a compact disk (CD) or a DVD is recorded in a predetermined location of the data recording/reproducing area. Such recording information recorded in the data recording/reproducing area includes location information, in other words, address data, recorded in each data row as well as actual recording information. Accordingly, an access to a predetermined data row can be performed by using the information corresponding to the TOC data and the address data of each data row.
[0043] Turning now to FIG. 9 , an information recording/reproducing apparatus for recording/reproducing information on/from a hologram memory medium according to an embodiment of the present invention is illustrated. As shown in FIG. 9 , the information recording/reproducing apparatus includes a hologram memory medium transferring motor 10 , an optical pickup 11 , a feed motor 12 , a signal process integrated circuit (IC) 13 , a central processing unit (CPU) 14 , and a driver integrated circuit (IC) 15 .
[0044] The hologram memory medium transferring motor 10 transfers a hologram memory medium 1 in a different direction from a reference line to the same distance as the shift amount of a shift multi-recording, at the end portion of the reference line. In addition, the transfer of the hologram memory medium transferring motor 10 is controlled by the output of the driver IC 15 .
[0045] The optical pickup 11 includes optical elements such as a laser light source, for example, a semiconductor laser, a collimator lens, an object lens, which is driven by a focus actuator or a tracking actuator, and a polarizing beam splitter, and a light receiving device.
[0046] The feed motor 12 moves the optical pickup 11 to a predetermined location along the hologram memory medium 1 . More specifically, in a search operation, the feed motor 12 controls the location of the optical pickup 11 by using a driving voltage supplied from the driver IC 15 . The driving voltage may be obtained, for example, based on the address data recorded on the hologram memory medium 1 .
[0047] The signal process IC 13 generates a reproducing signal based on a return light quantity from the hologram memory medium 1 that is received by the light receiving device (not shown) in the optical pickup 11 , while generating a focus error (FE) signal obtained by detecting a focus error of a radiation laser from the optical pickup 11 by an astigmatism method based on the return light quantity obtained by the light receiving device (not shown) in the optical pickup 11 . Furthermore, the signal process IC 13 generates a track error (TE) signal obtained by detecting an error in the radiation laser from the optical pickup 11 in a reference line direction by a push-pull method. In addition, the signal process IC 13 generates a focus driving (FODRV) signal and a tracking driving (TRDRV) signal based on the FE and TE signals.
[0048] The CPU 14 controls the information recording/reproducing apparatus based on a control program stored in an internal memory such as a read only memory (ROM). According to an embodiment of the present invention, the CPU 14 controls various servo operations when recording information on the hologram memory medium 1 . More specifically, the CPU 14 calculates a driving voltage of the feed motor 12 that is required to move the optical pickup 11 based on the present address data and the address data of a target location in a search operation, and supplies the driving voltage of the feed motor 12 to the driver IC 15 through the signal process IC 13 .
[0049] The driver IC 15 inputs the focus driving (FODRV) signal or the tracking driving (TRDRV) signal that are generated in the signal process IC 13 , and amplifies the input focus driving (FODRV) signal or tracking driving (TRDRV) signal to a predetermined size. Thereafter, the driver IC 15 supplies the amplified signal to a focus actuator or a tracking actuator.
[0050] Referring to FIG. 10 , an example optical system, such as an optical pickup 11 , shown in FIG. 9 , for use in an information recording/reproducing apparatus according to an embodiment of the present invention is illustrated. As shown in FIG. 10 , such an optical system includes a data recording/reproducing optical system 20 and a location determination controlling optical system 30 . The data recording/reproducing optical system 20 records information in the data recording/reproducing area of the hologram memory medium 1 and reproduces information from the data recording/reproducing area of the hologram memory medium 1 . The location determination controlling optical system 30 performs the location determination control of the object beam and the reference beam irradiated from the data recording/reproducing system 20 based on the servo information, when recording/reproducing information on/from the hologram memory medium 1 . In addition, the data recording/reproducing optical system 20 and the location determination controlling optical system 30 are integrally formed. In such a situation, the location determination controlling optical system 30 transfers inconnection with the transfer of the data recording/reproducing optical system 20 . However, the data recording/reproducing optical system 20 and the location determination controlling optical system 30 can also be physically separated. In such a situation, a control signal may be fed back from the location determination controlling optical system 30 to the data recording/reproducing optical system 20 so as to determine the location of the optical system.
[0051] Turning now to FIG. 11 , a method of recording information on a hologram memory medium utilizing an information recording/reproducing apparatus according to an embodiment of the present invention will now be described as follows.
[0052] When a hologram memory medium 1 is mounted in an information recording/reproducing apparatus in S 101 , a CPU 14 calculates a driving voltage of a feed motor 12 for transferring an optical pickup 11 based on address data from a location determination controlling optical system 30 in order to transfer the optical pickup 11 to a home position having recording information in the hologram memory medium 1 by supplying the driving voltage of the feed motor 12 to a driver IC 15 through a signal process IC 13 , in S 102 .
[0053] Thereafter, the CPU 14 reads information corresponding to table of content (TOC) data, which is recorded around the home position, from a reproducing signal from the location determination controlling optical system 30 in order to determine whether the information is preliminarily recorded on the hologram memory medium 1 , in S 103 . In the case where the information is not recorded on the hologram memory medium 1 , the data recording/reproducing optical system 20 is transferred to a predetermined recording start location, in S 104 .
[0054] In the case where the information is recorded on the hologram memory medium 1 , the data recording/reproducing optical system 20 is transferred to an address, which is obtained by shifting from the address of the last information by the amount corresponding to the shift amount of a shift multi-recording, in S 105 . When the recording/reproducing optical system 20 is transferred to a predetermined location, the data recording/reproducing optical system 20 radiates an object beam and a reference beam to the data recording/reproducing area of the hologram memory medium 1 to record predetermined information as interference stripes, in S 106 . Thereafter, the data recording/reproducing optical system 20 records information, while shifting by a predetermined amount based on location determination information, which is obtained from the location determination controlling optical system 30 .
[0055] As described from the foregoing, the present invention advantageously provides methods of recording/reproducing information on/from a card type hologram memory medium, in which a data recording/reproducing area of the hologram memory medium can be effectively used, and information can be continuously recorded and reproduced. As a result, the operation continuity can be secured, and the control of a data recording/reproducing optical system can be simplified. In addition, such recording/reproducing methods can advantageously utilize two-dimensional shift multi-recording and reproducing techniques.
[0056] While there have been illustrated and described what are considered to be example embodiments of the present invention, it will be understood by those skilled in the art and as technology develops that various changes and modification may be made, and equivalents may be substituted for elements thereof without departing from the spirit and scope of the present invention. Many modifications may be made to adapt the teachings of the present invention to a particular situation without departing from the scope thereof. For example, the hologram memory medium can be formed in different sizes and shapes, such as square, cube, spherical and elliptical shape, as long as information can be continuously recorded on or reproduced from the hologram memory medium without interruption. In addition, the hologram memory medium can be a recordable medium formed of a photo-polymer, a multi-waveguide type medium or a rewritable medium formed of photorefractive crystals, such as LiNbO 3 (lithium niobate). Similarly, the CPU can be implemented as a chipset having firmware, or alternatively, a general or special purposed computer programmed to perform the methods as described with reference to FIGS. 2-7 . Moreover, such a hologram memory medium can also have a wide range of applications, including multimedia computing, video-on demand, high-definition televisions, portable computing and consumer video. Accordingly, it is intended, therefore, that the present invention not be limited to the various example embodiments disclosed, but that the present invention includes all embodiments falling within the scope of the appended claims. | A method of recording/reproducing information on/from a card-shaped hologram memory medium is provided in which an information recording/reproducing optical system can be conveniently controlled to increase a recording capacity of the card-shaped hologram memory medium. In the method, pieces of information are sequentially recorded in a data recording/reproducing area of the card shaped hologram memory medium along a predetermined route, while maintaining a predetermined distance between pieces of information. | 26,824 |
CROSS-REFERENCE TO RELATED APPLICATIONS
The present invention is related to those disclosed in:
1) U.S. patent application Ser. No. 10/630,311, filed concurrently herewith, entitled “CIRCUITRY FOR REDUCING LEAKAGE CURRENTS IN A PRE-CHARGE CIRCUIT USING VERY SMALL MOSFET DEVICES;” and
2) U.S. patent application Ser. No. 10/630,504, filed concurrently herewith, entitled “CIRCUITRY FOR REDUCING LEAKAGE CURRENTS IN A TRANSMISSION GATE SWITCH USING VERY SMALL MOSFET DEVICES.”
U.S. patent application Ser. Nos. 10/630,311 and 10/630,504 are commonly assigned to the assignee of the present invention. The disclosures of the related patent applications are hereby incorporated by reference for all purposes as if fully set forth herein.
TECHNICAL FIELD OF THE INVENTION
The present invention is generally directed to analog circuits that are fabricated using small feature-sized MOSFET processes and, in particular, to a circuit that reduces sub-threshold leakage currents in small MOSFET devices connected to sensitive analog circuit nodes.
BACKGROUND OF THE INVENTION
As the feature size of MOSFET processes shrink, the MOSFET sub-threshold drain-to-source leakage current when the transistor is supposedly turned off becomes increasingly large. In analog circuits where it is critical for a node to stay at high impedance, this increased leakage current may no longer be ignored. When the devices connected to the high impedance node draw large enough leakage currents, the performance of the circuit may suffer significantly. For instance, in a phase-locked loop (PLL), the devices connected to the high-impedance node of the loop filter may draw enough current when the devices are supposedly off to cause jitter in the PLL output.
Therefore, there is a need in the art for improved analog circuits that are fabricated using small feature-sized MOSFET processes. In particular, there is a need for circuits that reduce the sub-threshold leakage currents in small MOSFET devices connected to sensitive analog circuit nodes.
SUMMARY OF THE INVENTION
Low leakage current versions of three commonly used analog switches are shown to demonstrate techniques of reducing MOSFET sub-threshold leakage currents which can be significant in modern small-feature-sized CMOS processes. These circuits may be coupled to the high-impedance node of a phase-locked loop (PLL), for example. The three circuits include 1) pull-up/pull-down devices, 2) a pre-charge circuit, and 3) a transmission switch (T-switch) for analog testing. It should be noted that the low leakage current designs disclosed herein are general purpose and are not necessarily limited to PLL designs.
To address the above-discussed deficiencies of the prior art, it is a primary object of the present invention to provide, for use with an operational circuit comprising at least one high-impedance node, a pull-down circuit capable of pulling the high-impedance node down to ground when a pull-down (PD) signal driving the pull-down circuit is Logic 1. According to an advantageous embodiment of the present invention, the pull-down circuit comprises: 1) a first pull-down N-channel transistor having a drain coupled to the high-impedance node, a gate coupled to the PD signal, and a source coupled to a common node; 2) a second pull-down N-channel transistor having a drain coupled to the common node, a gate coupled to the PD signal, and a source coupled to a ground rail;, wherein the first and second pull-down N-channel transistors are off when the PD signal is Logic 0 and are on when the PD signal is Logic 1; and 3) a gate-biasing circuit driven by the PD signal, wherein the gate-biasing circuit is off when the PD signal is Logic 1 and the gate-biasing circuit applies a Logic 1 bias voltage to the common node when the PD signal is Logic 0, the Logic 1 bias voltage creating a negative Vgs bias on the first pull-down N-channel transistor when the PD signal is Logic 0.
According to another embodiment of the present invention, the gate-biasing circuit comprises a P-channel transistor having a gate coupled to the PD signal, a drain coupled to the common node, and a source coupled to a VDD power supply rail.
According to still another embodiment of the present invention, the gate-biasing circuit comprises: 1) an inverter having an input coupled to the PD signal; and 2) a biasing N-channel transistor having a gate coupled to an output of the inverter, a source coupled to the common node, and a drain coupled to a VDD power supply rail.
It is another primary object of the present invention to provide, for use with an operational circuit comprising at least one high-impedance node, a pull-up circuit capable of pulling the high-impedance node up to a high voltage when a pull-up (PU*) signal driving the pull-up circuit is Logic 0. According to an advantageous embodiment of the present invention, the pull-up circuit comprises: 1) a first pull-up P-channel transistor having a drain coupled to the high-impedance node, a gate coupled to the PU* signal, and a source coupled to a common node; a second pull-up P-channel transistor having a drain coupled to the common node, a gate coupled to the PU* signal, and a source coupled to a VDD power supply rail, wherein the first and second pull-up P-channel transistors are off when the PU* signal is Logic 1 and are on when the PU* signal is Logic 0; and a gate-biasing circuit driven by the PU* signal, wherein the gate-biasing circuit is off when the PU* signal is Logic 0 and the gate-biasing circuit applies a Logic 0 bias voltage to the common node when the PU* signal is Logic 1, the Logic 0 bias voltage creating a positive Vgs bias on the first pull-up P-channel transistor when the PU* signal is Logic 1.
In another embodiment of the present invention, the gate-biasing circuit comprises a biasing N-channel transistor having a gate coupled to the PU* signal, a drain coupled to the common node, and a source coupled to a ground power rail.
In still another embodiment of the present invention, the gate-biasing circuit comprises: 1) an inverter having an input coupled to the PU* signal; and 2) a biasing P-channel transistor having a gate coupled to an output of the inverter, a source coupled to the common node, and a drain coupled to a ground power rail.
Before undertaking the DETAILED DESCRIPTION OF THE INVENTION below, it may be advantageous to set forth definitions of certain words and phrases used throughout this patent document: the terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation; the term “or,” is inclusive, meaning and/or; the phrases “associated with” and “associated therewith,” as well as derivatives thereof, may mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like; and the term “controller” means any device, system or part thereof that controls at least one operation. A controller may be implemented in hardware, firmware or software, or some combination of at least two of the same. It should be noted that the functionality associated with a controller may be centralized or distributed, whether locally or remotely. Definitions for certain words and phrases are provided throughout this patent document, those of ordinary skill in the art should understand that in many, if not most instances, such definitions apply to prior, as well as future uses of such defined words and phrases.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:
FIG. 1 illustrates an exemplary phase-locked loop (PLL) that incorporates commonly used analog switches in which MOSFET sub-threshold leakage currents are reduced according to the principles of the present invention;
FIG. 2A illustrates a conventional pull-down circuit according to an exemplary embodiment of the prior art;
FIG. 2B illustrates a conventional pull-up circuit according to an exemplary embodiment of the prior art;
FIG. 3A illustrates a pull-down circuit according to an exemplary embodiment of the present invention;
FIG. 3B illustrates a pull-up circuit according to an exemplary embodiment of the present invention
FIG. 4 illustrates a conventional pre-charge circuit according to an exemplary embodiment of the prior art;
FIG. 5 illustrates a pre-charge circuit according to an exemplary embodiment of the present invention;
FIG. 6 illustrates a conventional test circuit according to an exemplary embodiment of the prior art; and
FIG. 7 illustrates a test circuit according to an exemplary embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1 through 7 , discussed below, and the various embodiments used to describe the principles of the present invention in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the invention. Those skilled in the art will understand that the principles of the present invention may be implemented in any suitably arranged small feature-sized MOSFET device.
FIG. 1 illustrates exemplary phase-locked loop (PLL) 100 , which incorporates commonly used analog switches in which MOSFET sub-threshold leakage currents are reduced according to the principles of the present invention. PLL 100 comprises frequency divider 110 , phase-frequency detector 120 , charge pump and loop filter circuit 130 , voltage controlled oscillator 140 and frequency divider 160 . Frequency divider 110 divides the frequency of the input signal, VIN, by R, where R may be an integer of a fractional value. Frequency divider 150 divides the frequency of the output signal, VOUT, by N, where N may be an integer or a fractional value.
PFD 120 receives and compares the frequency-divided reference signal from frequency divider 110 and the frequency-divided feedback signal from frequency divider 150 . Depending on whether the frequency of the feedback signal is greater than or less than the frequency of the reference signal, PFD 130 generates either a Pump Up signal or a Pump Down signal that is applied to charge pump and loop filter 130 . If a Pump Up signal is received, charge pump and loop filter 130 adds charge to the loop filter, which is typically a large storage capacitor. If a Pump Down signal is received, charge pump and loop filter 130 discharges the loop filter. The voltage on the loop filter is the control voltage, VC, at the output of charge pump and loop filter 130 .
Voltage-controlled oscillator 140 produces the output signal, VOUT, which has a frequency that is controlled by the control voltage, CV. As the CV voltage increases, the frequency of the VOUT output signal increases. As the CV voltage decreases, the frequency of the VOUT output signal decreases. Thus, through the operation of the negative feedback path in PLL 150 , the frequency of the VOUT output signal is held at some multiple of the frequency of the VIN input signal, where the multiple is determined by the values of R and N of frequency dividers 110 and 150 , respectively.
FIG. 2A illustrates conventional pull-down circuit 210 according to an exemplary embodiment of the prior art. Pull-down circuit 210 comprises. N-channel transistor 210 , which has a gate coupled to the pull-down signal, PD, a drain coupled to the VC node at the output of charge pump and loop filter 130 , and a source coupled to the VSS power rail (e.g., ground rail). According to the exemplary embodiment, N-channel transistor 210 is a metal-oxide-silicon field effect transistor (MOSFET).
The VC node at the output of charge pump and loop filter 130 is a high impedance node. When the pull-down signal, PD, is at Logic 1, N-channel transistor 210 is turned on, thereby pulling the node VC to ground. This discharges the loop filter capacitor. When PD is Logic 0, N-channel transistor 210 is off and should not have any measurable effect on the PLL operation. If reality, however, if N-channel transistor 210 is made from a small-feature-sized CMOS process, the sub-threshold drain-to-source leakage current (Ids) when N-channel transistor 210 is off is no longer negligible. As a result, even if Vgs of N-channel transistor 210 is zero volts (0 V), Ids of N-channel transistor 210 could be on the order of hundreds of nano-amperes. In the case of PLL 100 , is this non-zero leakage current drains significant charge from the loop filter capacitor even when the PD signal is Logic 0, thereby causing unacceptably large amounts of jitter at the output of PLL 100 .
FIG. 2B illustrates conventional pull-up circuit 250 according to an exemplary embodiment of the prior art. Pull-up circuit 250 comprises P-channel transistor 250 , which has a gate coupled to the pull-up signal, PU*, a drain coupled to the VC node at the output of charge pump and loop filter 130 , and a source coupled to the VDD power supply rail. According to the exemplary embodiment, P-channel transistor 250 is a metal-oxide-silicon field effect transistor (MOSFET). The pull-up signal, PU* is an active low signal.
The VC node at the output of charge pump and loop filter 130 is a high impedance node. When the pull-up signal, PU*, is at Logic 0, P-channel transistor 250 is turned on, thereby pulling the node VC up to the. VDD rail voltage. This charges the loop filter capacitor. When PU* is Logic 1, P-channel transistor 250 is off and should not have any measurable effect on the PLL operation. If reality, however, if P-channel transistor 250 is made from a small-feature-sized CMOS process, the sub-threshold drain-to-source leakage current (Ids) when P-channel transistor 250 is off is no longer negligible. As a result, even if Vgs of P-channel transistor 250 is zero volts (0 V), Ids of P-channel transistor 250 could be on the order of hundreds of nano-amperes. In the case of PLL 100 , this non-zero leakage current adds significant charge to the loop filter capacitor even when the PU* signal is Logic 1, thereby causing unacceptably large amounts of jitter at the output of PLL 100 .
FIG. 3A illustrates pull-down circuit 300 according to an exemplary embodiment of the present invention. Pull-down circuit 300 comprises N-channel transistors 310 , 320 and 330 , and inverter 340 . The gates of N-channel transistors 310 and 320 are coupled to the pull-down signal, PD. The drain of N-channel transistor 310 is coupled to the VC node at the output of charge pump and loop filter 130 . The source of N-channel transistor 310 is coupled to the drain of N-channel transistor 320 . The source of N-channel transistor 320 is coupled to the VSS power rail (e.g., ground rail).
The input of inverter 340 is coupled to the pull-down signal, PD. The output of inverter 340 drives the gate of N-channel transistor 330 . The drain of N-channel transistor 330 is coupled to the VDD power supply rail. The source of N-channel transistor 330 is coupled to the drain of N-channel transistor 320 .
Pull-down circuit 300 performs the same function as the circuit in FIG. 2A , without the leakage problem. When the pull-down signal, PD, is Logic 1, N-channel transistors 310 and 320 are turned on, thereby pulling the VC node at the output of charge pump and loop filter 130 to ground. Also, when PD is Logic 1, N-channel transistor 330 is turned off and does nothing. It is noted the widths of N-channel transistors 310 and 320 are twice the width of N-channel transistor 210 in order to maintain the same pull-down impedance.
When the PD pull-down signal is Logic 0, N-channel transistors 310 and 320 are both off. At the same time, N-channel transistor 330 is turned on, thereby pulling the source of N-channel transistor 310 and the drain of N-channel transistor 320 up to the VDD rail (i.e., Logic 1). As a result, the Vgs voltage of N-channel transistor 310 is negative, rather than merely 0 volts. This is a “hard” shut-off that effectively reduces the sub-threshold leakage current of N-channel transistor 310 to a negligible amount, thereby avoiding leakage problems.
Other circuit designs may be used to create a negative Vgs voltage bias on N-channel transistor 310 . For example, in an alternate embodiment of the present invention, N-channel transistor 330 and inverter 340 may be replaced by a single P-channel transistor that has a gate coupled to the PD input signal, a source coupled to the VDD power supply rail, and a drain coupled to the source of N-channel transistor 310 .
FIG. 3B illustrates pull-up circuit 350 according to an exemplary embodiment of the present invention. Pull-up circuit 350 comprises P-channel transistors 360 and 370 , and N-channel transistor 380 . The gates of P-channel transistors 360 and 370 are coupled to the pull-up signal, PU*. The drain of P-channel transistor 370 is coupled to the VC node at the output of charge pump and loop filter 130 . The source of P-channel transistor 370 is coupled to the drain of P-channel transistor 360 . The source of P-channel transistor 360 is coupled to the VDD power supply rail.
The pull-up signal, PU* also drives the gate of N-channel transistor 380 . The source of N-channel transistor 380 is coupled to the VSS supply rail (i.e., ground). The drain of N-channel transistor 380 is coupled to the common node at the drain of P-channel transistor 360 and the source of P-channel transistor 370 .
Pull-up circuit 350 performs the same function as the circuit in FIG. 2B , without the leakage problem. When the pull-up signal, PU*, is Logic 0, P-channel transistors 360 and 370 are turned on, thereby pulling the VC node at the output of charge pump and loop filter 130 up to the VDD supply voltage. Also, when PU* is Logic 0, N-channel transistor 380 is turned off and does nothing. It is noted the widths of P-channel transistors 360 and 370 are twice the width of P-channel transistor 250 in order to maintain the same pull-up impedance.
When the pull-up signal, PU*, is Logic 1, P-channel transistors 360 and 370 are both off. At the same time, N-channel transistor 380 is turned on, thereby pulling the source of P-channel transistor 370 and the drain of P-channel transistor 360 down to ground (i.e., Logic 1). As a result, the Vgs voltage of P-channel transistor 370 is positive, rather than merely 0 volts. This is a “hard” shut-off that effectively reduces the sub-threshold leakage current of P-channel transistor 370 to a negligible amount, thereby avoiding leakage problems.
Other circuit designs may be used to create a positive Vgs voltage bias on P-channel transistor 310 . For example, in an alternate embodiment of the present invention, N-channel transistor 380 may be replaced by an inverter that is driven by the PU* pull-down signal and a single P-channel transistor that has a gate coupled to the output of the inverter. The P-channel transistor would also have a drain coupled to the VSS power supply rail, and a source coupled to the source of P-channel transistor 370 .
FIG. 4 illustrates conventional pre-charge circuit 400 in exemplary charge pump and loop filter 130 according to an exemplary embodiment of the prior art. Pre-charge circuit 400 comprises P-channel transistors 421 - 425 , N-channel transistor 431 , and inverter 410 . P-channel transistor 425 and N-channel transistor 431 form a transmission gate switch. When the Pre-Charge input signal is at Logic 1, pre-charge circuit 400 is enabled and P-channel transistor 425 and N-channel transistor 431 are both on. When the Pre-Charge input signal is at Logic 0, pre-charge circuit 400 is disabled and P-channel transistor 425 and N-channel transistor 431 are both off.
When Pre-Charge=1, P-channel transistor 421 is off and P-channel transistor 422 is on. When Pre-Charge=0, P-channel transistor 421 is on and P-channel transistor 422 is off. P-channel transistor 423 and P-channel transistor 424 are connected as diodes (i.e., Vgd=0). It is noted that the gate and drain of P-channel transistor 424 are directly connected together (i.e., Vgd=0 always) and the gate and drain of P-channel transistor 423 are shorted together when P-channel transistor 422 is on (i.e., Vgd=0 when Pre-Charge=1). Because P-channel transistor 423 and P-channel transistor 424 are the same type and size devices and are connected in series between the VDD rail and the VSS rail (i.e., ground), the voltage, VMID, at the drain of P-channel transistor 422 is VDD/2.
When Pre-Charge=1, the transmission gate switch formed by P-channel transistor 425 and N-channel transistor 431 is on (i.e., closed), thereby shorting the VMID node to the VC node. This drives the high-impedance VC node to approximately VDD/2. When Pre-Charge=0, the transmission gate switch is off, thereby isolating the VMID node from the VC node. Also, when Pre-Charge=0, P-channel transistor 422 is off and P-channel transistor 421 is on, thereby shorting the gate of P-channel transistor 423 to the VDD rail. Since the source of P-channel transistor 421 also is connected to the VDD rail, the Vgs for P-channel transistor 423 is zero and P-channel transistor 423 is off. This cuts off current flow through P-channel transistor 423 and P-channel transistor 424 .
Unfortunately, pre-charge circuit 400 experiences high leakage current when pre-charge circuit 400 is disabled. When Pre-Charge=0, P-channel transistor 423 is off, but P-channel transistor 424 is still on Thus, the VMID node sits at approximately 0 volts. Since Pre-charge=0 is coupled to the gate of N-channel transistor 431 and VMID=0 is coupled to the source of N-channel transistor 431 , the Vgs of N-channel transistor 431 is approximately 0 volts. This permits sub-threshold leakage currents in small-feature-sized processes. Therefore, a leakage current path forms between the high impedance node, VC, and the VSS rail (i.e., ground) through N-channel transistor 431 and P-channel transistor 424 .
FIG. 5 illustrates pre-charge circuit 500 in exemplary charge pump and loop filter 130 according to an exemplary embodiment of the present invention. Pre-charge circuit 500 comprises P-channel transistors 521 - 525 , N-channel transistors 531 - 534 , and inverter 510 . P-channel transistor 525 and N-channel transistor 534 form a transmission gate switch. When the Pre-Charge input signal is at Logic 1, pre-charge circuit 500 is enabled and P-channel transistor 525 and N-channel transistor 534 are both on. When the Pre-Charge input signal is at Logic 0, pre-charge circuit 500 is disabled and P-channel transistor 525 and N-channel transistor 534 are both off.
When Pre-Charge=1, P-channel transistors 521 and 523 are off and N-channel transistors 531 and 532 are on. When Pre-Charge=0, P-channel transistors 521 and 523 are on and N-channel transistors 531 and 532 are off. When Pre-Charge=1, P-channel transistor 522 and P-channel transistor 524 are connected as diodes (i.e., Vgd=0). The gate and drain of P-channel transistor 522 are shorted together when N-channel transistor 531 is on (i.e., Vgd=0 when Pre-charge=1). Similarly, the gate and drain of P-channel transistor 524 are shorted together when N-channel transistor 532 is on (i.e., Vgd=0 when Pre-Charge=1). Because P-channel transistor 522 and P-channel transistor 524 are the same type and size devices and are connected in series between the VDD rail and the VSS rail (i.e., ground), the voltage, VMID, at the drain of P-channel transistor 522 is VDD/2.
The gate and source of N-channel transistor 533 are connected together, so that N-channel transistor 533 is off all the time. N-channel transistor 533 has negligible effect when P-channel transistors 522 and 524 are on. However, when Pre-Charge=0, P-channel transistors 521 and 523 are on and N-channel transistors 531 and 532 are off. Since P-channel transistors 521 and 523 are both on, the gate-to-source voltages (Vgs) of P-channel transistors 522 and 524 are both 0 volts. Therefore, P-channel transistors 522 and 524 are off.
Because P-channel transistors 522 and 524 are the same type and size devices, the impedances of P-channel transistors 522 and 524 are approximately the same when P-channel transistors 522 and 524 are off. When pre-charge circuit 500 is in this state, N-channel transistor 533 is off, but has a Vgs of zero volts and therefore has a sub-threshold leakage current. It is noted that when Pre-Charge=0, P-channel transistor 523 is on and shorts the VMID node to the drain of N-channel transistor 532 , which is off. However, N-channel transistor 532 still has a sub-threshold leakage current that can discharge the VMID node through P-channel transistor 523 . Therefore, N-channel transistor 533 is introduced to cancel the leakage current of N-channel transistor 532 . In this way, the VMID node sits at approximately VDD/2. Note the size of N-channel transistor 533 is larger than the size of N-channel transistor 532 in order to compensate for the body effect of N-channel transistor 533 when an n-well process is used.
The source of N-channel transistor 534 is coupled to the VMID node and the drain of N-channel transistor 534 is coupled to the VC node. The source of P-channel transistor 525 is coupled to the VMID node and the drain of P-channel transistor 525 is coupled to the VC node. When the VMID node is at VDD/2, the sub-threshold leakage currents of both N-channel transistor 534 and P-channel transistor 525 are negligible because N-channel transistor 534 and P-channel transistor 525 are both “hard” off. That is, the Vgs bias of N-channel transistor 534 is negative (i.e., −VDD/2) and the Vsg bias of P-channel transistor 525 is positive (i.e., +VDD/2).
FIG. 6 illustrates conventional test circuit 600 according to an exemplary embodiment of the prior art. For measurement purposes, test circuit 600 transmits the voltage at an internal node (the VC voltage in this case) to an externally accessible test point, namely the input/output (I/O) pad VEXT. Test circuit 600 comprises N-channel transistors 611 - 613 , P-channel transistors 621 and 622 , and inverter 630 . N-channel transistor 611 and P-channel transistor 621 form a first transmission gate switch. N-channel transistor 612 and P-channel transistor 622 form a second transmission gate switch. N-channel transistor 613 operates as a pull-down device.
When the ON signal is Logic 1, N-channel transistors 611 and 612 are on, P-channel transistors 621 and 622 are on, and N-channel transistor 613 is off. Since both transmission gates are on, the VC node is shorted to the VEXT node. This allows the user to either monitor or drive the internal analog node, VC. When the ON is Logic 0, both transmission switches are off and N-channel transistor 613 is on and pulls the V 1 node between the transmission switches to ground. This is done to minimize potential interferences from the VEXT external node to internal node VC via capacitive couplings. As in the cases of pull-down circuit 210 and pre-charge circuit 400 , a sub-threshold leakage current path exists from the VC to ground through N-channel transistor 611 and N-channel transistor 613 when test circuit 600 is off.
FIG. 7 illustrates test circuit 700 according to an exemplary embodiment of the present invention. For measurement purposes, test circuit 700 transmits the voltage at an internal node (the VC voltage in this case) to an externally accessible test point, namely the input/output (I/O) pad VEXT. Test circuit 700 comprises N-channel transistors 711 - 715 , P-channel transistors 721 - 723 , and inverter 730 . N-channel transistor 711 and P-channel transistor 721 form a first transmission gate switch. N-channel transistor 712 and P-channel transistor 722 form a second transmission gate switch. N-channel transistor 713 and P-channel transistor 723 form a third transmission gate switch. N-channel transistor 715 operates as a pull-down device. The gate and source of N-channel transistor 714 are coupled together (i.e., Vgs=0), so that N-channel transistor 714 is always off. However, N-channel transistor 714 has a sub-threshold leakage current when Vgs=0.
When the ON signal is Logic 1, all three transmission gate switches are on, allowing test circuit 700 to function in a manner similar to test circuit 600 . However, the switch sizes in test circuit 700 are 50% larger than those in test circuit 600 to maintain the same on-resistance. When the ON signal is Logic 0, all three transmission gate switches are off. The V 1 node is pulled down to ground by N-channel transistor 715 , keeping interference low.
However, the sub-threshold leakage current path is eliminated in test circuit 700 . N-channel transistor 712 is still leaky because its Vgs is 0 volts. However, N-channel transistor 714 is also leaky and has approximately the same impedance as N-channel transistor 712 . So the voltage at the V 2 node is approximately VDD/2 when the V 1 node is pulled down to ground. It is noted that the size of N-channel transistor 714 is bigger than the size of N-channel transistor 712 to compensate for the body effect. Because the V 2 node is at VDD/2 when the V 1 node is at ground and the ON signal is Logic 0, N-channel transistor 711 and P-channel transistor are “hard” off (i.e., Vgs<0 for N-channel transistor 711 and Vgs>0 for P-channel transistor 721 ). Hence, there is a negligible amount of leakage current and no leaky path is connected to the VC node.
The above-described circuits can be used to reduce sub-threshold leakage currents in small-feature-sized CMOS processes. All three circuits involve leaky switches when the Vgs values of the MOSFET devices are 0 volts (i.e., when the switches are off). The new circuit designs modify the prior art circuits such that the leakage paths are eliminated by making Vgs<0 for the N-channel devices and Vgs>0 for the P-channel devices. This is accomplished without impacting circuit performances or affecting power consumption.
Although the present invention has been described with an exemplary embodiment, various changes and modifications may be suggested to one skilled in the art. It is intended that the present invention encompass such changes and modifications as fall within the scope of the appended claims. | A pull-down circuit for pulling a high-impedance node to ground when a pull-down (PD) signal driving the pull-down circuit is Logic 1. The pull-down circuit comprises: 1) a first pull-down N-channel transistor having a drain coupled to the high-impedance node, a gate coupled to the PD signal, and a source coupled to a common node; 2) a second pull-down N-channel transistor having a drain coupled to the common node, a gate coupled to the PD signal, and a source coupled to a ground rail;, wherein the first and second pull-down N-channel transistors are off when the PD signal is Logic 0 and are on when the PD signal is Logic 1; and 3) a gate-biasing circuit driven by the PD signal. The gate-biasing circuit is off when the PD signal is Logic 1 and the gate-biasing circuit applies a Logic 1 bias voltage to the common node when the PD signal is Logic 0. The Logic 1 bias voltage creates a negative Vgs bias on the first pull-down N-channel transistor when the PD signal is Logic 0. An analogous pull-up circuit also is disclosed. | 31,318 |
BACKGROUND INFORMATION
1. Field
The present disclosure relates generally to aircraft and in particular to a method and apparatus for controlling the flight of an aircraft. Still more particularly, the present disclosure relates to a method, apparatus, and computer program product for controlling thrust generated by the engine of an aircraft.
2. Background
Takeoff is a phase of flight when an aircraft transitions from moving along the ground to flying in the air. An aircraft may make this transition when a takeoff speed is reached. The takeoff speed for an aircraft may vary based on a number of factors. These factors include, for example, air density, aircraft gross weight, aircraft configuration, and other suitable factors.
The speed needed for a takeoff is relative to the motion of the air. For example, headwind reduces the amount of groundspeed at the point of takeoff. In contrast, a tailwind increases the groundspeed at the point of takeoff.
The amount of thrust generated by an engine may affect the maintenance schedule required for an engine. For example, when crosswinds are present, the air into an inlet for an engine may separate. This separation of air may provide poor aerodynamics with respect to fan blades within the engine. If the engine is providing a high-level thrust, poor aerodynamics may cause vibrations on the fan blades.
These vibrations may result in requiring more frequent replacement or maintenance of the blades. This type of increased maintenance increases cost and makes the aircraft unavailable more often. One solution is to restrict engine power to a selected level until the forward speed is such that adverse aerodynamics at an inlet of an engine no longer occurs.
SUMMARY
In one advantageous embodiment, a method is presented for controlling thrust generated by an aircraft. A command is received for a selected level of thrust for the aircraft. A level of thrust provided by an engine for the aircraft is controlled based on a groundspeed and an airspeed of the aircraft in response to receiving the command.
In another advantageous embodiment, an apparatus comprises a thrust control process and a processor unit. The thrust control process may be capable of receiving a command for a selected level of thrust generated by an engine. The thrust control process may control a level of thrust provided by the engine based on a groundspeed and an airspeed of an aircraft in response to receiving the command. The thrust control process may execute on the processor unit.
In yet another advantageous embodiment, a computer program product for controlling thrust generated by an aircraft comprises a computer recordable storage medium, and program code stored on the computer recordable storage medium. Program code may be present for receiving a command for a selected level of thrust for the aircraft. Program code may also be present for controlling a level of thrust provided by an engine for the aircraft based on a groundspeed and an airspeed of the aircraft in response to receiving the command.
The features, functions, and advantages can be achieved independently in various embodiments of the present disclosure or may be combined in yet other embodiments in which further details can be seen with reference to the following description and drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
The novel features believed characteristic of the advantageous embodiments are set forth in the appended claims. The advantageous embodiments, however, as well as a preferred mode of use, further objectives and advantages thereof, will best be understood by reference to the following detailed description of an advantageous embodiment of the present disclosure when read in conjunction with the accompanying drawings, wherein:
FIG. 1 is a diagram of an aircraft in which an advantageous embodiment may be implemented;
FIG. 2 is a diagram of a data processing system in accordance with an advantageous embodiment;
FIG. 3 is a diagram illustrating a thrust control system in accordance with an advantageous embodiment;
FIG. 4 is a diagram illustrating a thrust control unit in accordance with an advantageous embodiment;
FIG. 5 is a diagram illustrating limits supplied to engine thrust in accordance with an advantageous embodiment;
FIG. 6 is a diagram illustrating limits for thrust in accordance with an advantageous embodiment;
FIG. 7 is a diagram illustrating limits for thrust in accordance with an advantageous embodiment;
FIG. 8 is a diagram illustrating logic for controlling thrust in accordance with an advantageous embodiment;
FIG. 9 is a diagram illustrating logic to generate or enable a groundspeed limit enable signal in accordance with an advantageous embodiment;
FIG. 10 is a diagram illustrating logic to generate an airspeed limit enable signal in accordance with an advantageous embodiment;
FIG. 11 is a high level flowchart of a process for controlling thrust generated by an aircraft in accordance with an advantageous embodiment;
FIG. 12 is a flowchart of a process for controlling thrust generated by an aircraft in accordance with an advantageous embodiment;
FIG. 13 is a flowchart of a process for enabling and disabling a groundspeed limit in accordance with an advantageous embodiment; and
FIG. 14 is a flowchart of a process for enabling and disabling an airspeed limit in accordance with an advantageous embodiment.
DETAILED DESCRIPTION
With reference now to the figures, and in particular, with reference to FIG. 1 , a diagram of an aircraft is depicted in which an advantageous embodiment may be implemented. Aircraft 100 is an example of an aircraft in which a method and apparatus for controlling engine power may be implemented. In this illustrative example, aircraft 100 has wings 102 and 104 attached to body 106 . Aircraft 100 includes wing mounted engine 108 , wing mounted engine 110 , and tail 112 . In particular, the different advantageous embodiments may control a level of thrust that may be generated by wing mounted engine 108 and wing mounted engine 110 when aircraft 100 is on the ground.
Although a wing mounted twin engine aircraft is illustrated in FIG. 1 , this illustration is provided for purposes of illustrating one type of aircraft in which different advantageous embodiments may be implemented. The different advantageous embodiments may be implemented on other types of aircraft with other numbers of engines and/or configurations of engines.
Turning now to FIG. 2 , a diagram of a data processing system is depicted in accordance with an advantageous embodiment. Data processing system 200 is an example of a data processing that may be implemented within aircraft 100 in FIG. 1 . Data processing system 200 may be found in various systems for aircraft 100 . For example, data processing system 200 may be implemented in components used to control the engines.
In these different advantageous embodiments, data processing system 200 may be configured to control the thrust generated by these types of engines. In this illustrative example, data processing system 200 includes communications fabric 202 , which provides communications between processor unit 204 , memory 206 , persistent storage 208 , communications unit 210 , input/output (I/O) unit 212 , and display 214 .
Processor unit 204 serves to execute instructions for software that may be loaded into memory 206 . Processor unit 204 may be a set of one or more processors or may be a multi-processor core, depending on the particular implementation. Further, processor unit 204 may be implemented using one or more heterogeneous processor systems in which a main processor is present with secondary processors on a single chip. As another illustrative example, processor unit 204 may be a symmetric multi-processor system containing multiple processors of the same type.
Memory 206 and persistent storage 208 are examples of storage devices. A storage device is any piece of hardware that is capable of storing information either on a temporary basis and/or a permanent basis. Memory 206 , in these examples, may be, for example, a random access memory or any other suitable volatile or non-volatile storage device. Persistent storage 208 may take various forms depending on the particular implementation.
For example, persistent storage 208 may contain one or more components or devices. For example, persistent storage 208 may be a hard drive, a flash memory, or some combination of the above. The media used by persistent storage 208 also may be removable. For example, a removable hard drive may be used for persistent storage 208 .
Communications unit 210 , in these examples, provides for communications with other data processing systems or devices. In these examples, communications unit 210 is a network interface card. Communications unit 210 may provide communications through the use of either or both physical and wireless communications links.
Input/output unit 212 allows for input and output of data with other devices that may be connected to data processing system 200 . For example, input/output unit 212 may provide a connection for user input through a keyboard and mouse. Display 214 provides a mechanism to display information to a user.
Instructions for the operating system and applications or programs are located on persistent storage 208 . These instructions may be loaded into memory 206 for execution by processor unit 204 . The processes of the different embodiments may be performed by processor unit 204 using computer implemented instructions, which may be located in a memory, such as memory 206 .
These instructions are referred to as program code, computer usable program code, or computer readable program code that may be read and executed by a processor in processor unit 204 . The program code in the different embodiments may be embodied on different physical or tangible computer readable media, such as memory 206 or persistent storage 208 .
Program code 216 is a functional form and located on computer readable media 218 that is selectively removable and may be loaded onto or transferred to data processing system 200 for execution by processor unit 204 . Program code 216 and computer readable media 218 form computer program product 220 in these examples.
In one example, computer readable media 218 may be in a tangible form, such as, for example, an optical or magnetic disc that is inserted or placed into a drive or other device that is part of persistent storage 208 for transfer onto a storage device, such as a hard drive that is part of persistent storage 208 .
In a tangible form, computer readable media 218 also may take the form of a persistent storage, such as a hard drive, a thumb drive, or a flash memory that is connected to data processing system 200 . The tangible form of computer readable media 218 is also referred to as computer recordable storage media. In some instances, computer readable media 218 may not be removable.
Alternatively, program code 216 may be transferred to data processing system 200 from computer readable media 218 through a communications link to communications unit 210 and/or through a connection to input/output unit 212 . The communications link and/or the connection may be physical or wireless in the illustrative examples. The computer readable media also may take the form of non-tangible media, such as communications links or wireless transmissions containing the program code.
In some illustrative embodiments, program code 216 may be downloaded over a network to persistent storage 208 from another device or data processing system for use within data processing system 200 . For instance, program code stored in a computer readable storage medium in a server data processing system may be downloaded over a network from the server to data processing system 200 . The data processing system providing program code 216 may be a server computer, a client computer, or some other device capable of storing and transmitting program code 216 .
The different components illustrated for data processing system 200 are not meant to provide architectural limitations to the manner in which different embodiments may be implemented. The different illustrative embodiments may be implemented in a data processing system including components in addition to or in place of those illustrated for data processing system 200 . Other components shown in FIG. 2 can be varied from the illustrative examples shown.
As one example, a storage device in data processing system 200 is any hardware apparatus that may store data. Memory 206 , persistent storage 208 and computer readable media 218 are examples of storage devices in a tangible form.
In another example, a bus system may be used to implement communications fabric 202 and may be comprised of one or more buses, such as a system bus or an input/output bus. Of course, the bus system may be implemented using any suitable type of architecture that provides for a transfer of data between different components or devices attached to the bus system.
Additionally, a communications unit may include one or more devices used to transmit and receive data, such as a modem or a network adapter. Further, a memory may be, for example, memory 206 or a cache such as found in an interface and memory controller hub that may be present in communications fabric 202 .
The different advantageous embodiments recognize and take into account that currently used systems for limiting engine power may be insufficient. The different advantageous embodiments recognize that currently used systems ramp and/or allow an increase in the maximum engine power based on airspeed.
The different advantageous embodiments recognize that using only airspeed may have a susceptibility to the thrust appearing to stop less than the target thrust until sufficient airspeed is attained. Further, the different advantageous embodiments also recognize that the use of airspeed to control the amount of thrust may allow the thrust to be reduced if a gust of wind causes a reduction in airspeed.
For example, if a pilot commands or selects full power while applying pressure on the brakes, the engines may increase thrust and hold at around 96 percent power. Once the brakes are released and the aircraft begins to roll forward, the engine power may remain at around 96 percent until the airspeed exceeds a certain threshold. This threshold may be around 30 knots. At this point, the thrust may be ramped or increased to 100 percent power using a linear ramp with increasing airspeed.
The different advantageous embodiments, recognize and take into account that situations may exist in which using airspeed to ramp thrust may not result in a linear or smooth increase in power as expected by a pilot. For example, if the aircraft begins rolling forward as the throttles are advanced such that 30 knots of airspeed is achieved before the engines have reached 96 percent power, little, if any, pause in engine power may exist.
Further, wind gusts may produce a noticeable rollback or reduction in thrust when these wind gusts reduce the airspeed of the aircraft. The different advantageous embodiments recognize and take into account that a concern may be present in which a pilot may perceive an unusual delay or rollback of the engines as an anomaly and abort a takeoff.
Thus, the different advantageous embodiments provide a method and apparatus for limiting thrust in a manner that presents a pilot with a continuously increasing thrust. This limit also ensures that a fan blade threshold is met such that undesirable vibrations that may require more frequent maintenance or sooner maintenance may be avoided. The different advantageous embodiments use a groundspeed limit and an airspeed limit to limit the amount of thrust generated by an engine. This type of system may provide a limit for the amount of thrust, but may allow for continuous thrust increase during a rolling takeoff procedure.
When a command is received for a selected level of thrust for an aircraft, the level of thrust provided by the engine may be based both on the groundspeed and the airspeed of the aircraft. A determination may be made as to whether a groundspeed limit for the thrust is to be used based on the groundspeed and the airspeed. In response to the groundspeed limit being present, the level of thrust is provided using the lower value generated between the groundspeed limit and airspeed limit.
In response to the groundspeed limit not being used, the level of thrust may be provided using the airspeed limit. At some speed of travel on the ground, the airspeed limit also may no longer be used. Further, one or more of the airspeed limit and the groundspeed limit also may be used again after this use if the requested level of thrust is less than the groundspeed limit and the groundspeed falls below some threshold.
In the different advantageous embodiments, the commanded level and the actual level of thrust is displayed to the operator. The operator may observe a lag as the thrust increases, but is less likely to mistakenly identify the lag and/or limits as an anomaly in the engine.
Turning now to FIG. 3 , a diagram illustrating a thrust control system is depicted in accordance with an advantageous embodiment. Thrust control system 300 may be implemented using a data processing system such as, for example, data processing system 200 in FIG. 2 .
In this example, thrust control system 300 includes throttle controller 302 , thrust control unit 304 , groundspeed sensor 306 , airspeed sensor 308 , and engine 310 . Throttle controller 302 may be a controller located in a cockpit of an aircraft such as, for example, aircraft 100 . Thrust control unit 304 may be a computer physically located at engine 310 . Thrust control unit 304 receives input from groundspeed sensor 306 and airspeed sensor 308 .
These various components illustrated for thrust control system 300 may be implemented using currently available components. For example, airspeed sensor 308 may detect airspeed based on impact pressure. For example, airspeed sensor 308 may detect a pressure difference caused by forward motion, which may be total pressure minus static pressure.
Groundspeed sensor 306 may be, for example, an inertially based sensor, a global positioning system sensor, or some other suitable type of device. The different advantageous embodiments recognize that an airspeed detected by airspeed sensor 308 may be invalid at speeds less than around 30 knots.
With reference now to FIG. 4 , a diagram illustrating a thrust control unit is depicted in accordance with an advantageous embodiment. In this example, thrust control unit 400 is a more detailed example of thrust control unit 304 in FIG. 3 .
In this example, thrust control unit 400 includes thrust control process 402 , groundspeed limit unit 404 , airspeed limit unit 406 , and policy 408 . Thrust control process 402 may receive commanded thrust 410 as an input. Commanded thrust 410 may be received from a controller such as, for example, throttle controller 302 in FIG. 3 .
Commanded thrust 410 is a command indicating the level of thrust desired by a pilot. Thrust control process 402 also may receive airspeed 412 and groundspeed 414 as inputs when generating engine command 416 . Engine command 416 is the command actually sent to the engine by thrust control unit 400 and may vary from commanded thrust 410 , depending on the application of policy 408 .
Policy 408 is a set of rules. A set as used herein refers to one or more items. For example, a set of rules is one or more rules. Policy 408 may be used by thrust control process 402 to determine whether groundspeed limit unit 404 and/or airspeed limit unit 406 should be used to provide limits when generating engine command 416 . If neither groundspeed limit 404 nor airspeed limit 406 limit is applied, engine command 416 may be the same as commanded thrust 410 . Groundspeed limit unit 404 and airspeed limit unit 406 are functions that may be used to limit the amount of thrust in engine command 416 .
The limits generated by these units may be used to limit the amount of thrust requested in commanded thrust 410 . In other words, groundspeed limit unit 404 and/or airspeed limit unit 406 may generate limits for the level of thrust for engine command 416 . With the limits that may be generated by groundspeed limit unit 404 and/or airspeed limit unit 406 , engine command 416 may provide a level of thrust that is less than commanded thrust 410 depending on the speed of aircraft.
In these examples, groundspeed limit unit 404 applies when the groundspeed of the aircraft is less than some limit. Groundspeed limit unit 404 may be disabled when the groundspeed or the airspeed exceeds some threshold. The threshold for the groundspeed and airspeed are different in these examples. The groundspeed threshold for disabling groundspeed limit unit 404 may be higher than the airspeed threshold in these examples.
Groundspeed limit unit 404 is implemented as a ramp function using groundspeed 414 . In this manner, the thrust may increase continuously from a lower limit up to an upper limit. This upper limit in these examples is an airspeed thrust limit. This airspeed thrust limit may be set at a level to prevent undesirable vibrations in the fan blades that may occur due to changes in aerodynamics caused by crosswinds. In these illustrative examples, groundspeed limit unit 404 may be implemented in a number of different ways. For example, groundspeed limit unit 404 may be implemented as a table, a series of equations, or some other suitable function.
For example, groundspeed limit unit 404 may provide for a groundspeed using the following equation:
maximum thrust=((6/55)*groundspeed)+90.
Alternatively, a table may set the limit for the thrust based on the groundspeed.
Airspeed limit unit 406 is an upper limit to the thrust that may be commanded. This limit also may be disabled when the airspeed is above a selected level. In these examples, airspeed limit unit 406 may be implemented using logical hysteresis or any other suitable function or process. For example, the limit may switch off when airspeed increases from some airspeed to another airspeed.
Further, the limit may be switched on or used when the airspeed decreases from a higher airspeed to a lesser airspeed. For example, the limit may be 96 percent of the maximum thrust when the airspeed is less than 50 knots. When the airspeed becomes greater than 50 knots, the limit is then the maximum thrust. The limit may be turned back on if the airspeed decreases from a level that is greater than 35 knots to less than 35 knots. When that occurs, the limit may be set to 96 percent of the maximum thrust rather than providing maximum thrust.
With reference now to FIG. 5 , a diagram illustrating limits supplied to engine thrust is depicted in accordance with an advantageous embodiment. In this example, graph 500 illustrates groundspeed on horizontal axis 502 and airspeed on horizontal axis 504 . The thrust is a percentage of maximum thrust. Thrust in percent is represented by vertical axis 505 . Line 506 illustrates a groundspeed limit, while line 508 illustrates an airspeed limit. Line 510 illustrates a resulting limit from these two limits. The resulting limit in line 510 may change depending on whether wind is present.
In this example, no wind is present. The groundspeed limit represented by line 506 is level until 10 knots groundspeed is reached. The amount of thrust that may be generated increases as a ramp until 65 knots is reached. At 65 knots, the thrust limit is level. The airspeed limit represented by line 508 is level until an airspeed of 50 knots is reached. At that point, the airspeed limit is removed and the maximum thrust may be generated. As can be seen by this example, the groundspeed limit is removed when the airspeed reaches 50 knots.
With reference now to FIG. 6 , a diagram illustrating limits for thrust is depicted in accordance with an advantageous embodiment. In this example, graph 600 , horizontal axis 602 represents groundspeed, while horizontal axis 604 represents airspeed. Vertical axis 606 represents thrust. Line 608 represents a groundspeed limit, while line 610 represents an airspeed limit. Line 612 represents a resulting limit from these two limits.
In this example, a 15 knot headwind is encountered by the aircraft. As can be seen, an airspeed of 50 knots is reached more quickly as compared to graph 500 with the presence of a headwind. When 50 knots is reached, the groundspeed limit is no longer effective. Further, the airspeed limit is also removed resulting in power being increased to a maximum thrust for the engine.
With reference now to FIG. 7 , a diagram illustrating limits for thrust is depicted in accordance with an advantageous embodiment. In graph 700 , horizontal axis 702 represents groundspeed, while horizontal axis 704 represents airspeed. Vertical axis 706 represents thrust. Line 708 represents a groundspeed limit, while line 710 represents an airspeed limit. Line 712 illustrates the resulting limit between the airspeed limit and the groundspeed limit.
In this example, a 15 knot tailwind is present. As a result, an airspeed of 50 knots is not reached until the groundspeed of 65 knots also is reached. As a result, the limit is not removed until the groundspeed has reached 65 knots in this example.
With reference to FIGS. 8-10 , an example of logic for a thrust control process is depicted in accordance with an advantageous embodiment. The logic illustrated in FIGS. 8-10 are simplified diagrams of logic that may be used.
These simplified diagrams are presented for purposes of illustrating logic on a high level for use in a thrust control process, such as thrust control process 402 . The actual logic used to implement these processes may include other logic components in addition to or in place of the ones depicted in these figures.
With reference now to FIG. 8 , a diagram illustrating logic for controlling thrust is depicted in accordance with an advantageous embodiment. Logic 800 in FIG. 8 is an example of logic that may be implemented in thrust control process 402 in FIG. 4 .
In this example, logic 800 receives command 802 as an input. Logic 800 also receives groundspeed 804 , groundspeed limit enable 806 , airspeed 808 , and airspeed limit enable 810 as inputs.
Groundspeed 804 is sent to groundspeed limit unit 812 . The output of groundspeed limit unit 812 is a groundspeed limit for a thrust level that is based on groundspeed 804 . The output of groundspeed limit unit 812 may be a thrust level that is less than that in command 802 . When groundspeed limit enable is a logic “1”, groundspeed limit unit 812 is used to control thrust. This thrust level is input into switch 814 . Switch 814 may be enabled by groundspeed limit enable 806 . Additionally, command 802 also is input into switch 814 . The output of switch 814 is sent into minimum unit 816 .
Airspeed 808 is entered as an input into airspeed limit unit 818 . Airspeed limit unit 818 generates an airspeed limit for a thrust level based on airspeed 808 . The output of airspeed limit unit 818 may be a thrust level that is less than the amount of thrust requested by command 802 . This thrust level is sent to switch 820 . Switch 820 also receives command 802 as an input. Switch 820 may be enabled by airspeed limit enable 810 . When airspeed limit enable is a logic “1”, airspeed limit unit 818 is used to control thrust. The output of switch 820 is sent to minimum unit 816 .
Minimum unit 816 selects the lower value of the outputs of switch 814 and switch 820 . In these examples, groundspeed limit unit 812 is typically a lower limit than airspeed limit unit 818 . Then this output forms command 822 which is used to control the engine.
In these examples, command 802 also forms thrust display 824 which is an output for the display that is seen by the pilot. In the different advantageous embodiments, although command 822 may be lower than command 802 , the pilot sees the same level of commanded thrust in command display 824 as command 802 . The pilot may perceive a lag in the thrust increasing as the airspeed increases. This increase in thrust, however, may be maintained as a constant increase to avoid aborting a takeoff when an engine anomaly is not actually present.
With reference now to FIG. 9 , a diagram illustrating logic to enable a groundspeed limit is depicted in accordance with an advantageous embodiment. In this example, logic 900 receives a number of different inputs. These inputs include aircraft on ground 902 , groundspeed valid 904 , groundspeed 906 , constant 908 , airspeed valid 910 , airspeed 912 , and constant 914 .
In this example, aircraft on ground 902 indicates whether the aircraft is on the ground. A logic “1” indicates that the aircraft is on the ground in these examples. Groundspeed valid 904 is a logic “1” if the groundspeed is valid. Groundspeed 906 is the groundspeed detected by a groundspeed sensor. A groundspeed may not be valid if, for example, a groundspeed sensor is disabled or faulty. Constant 908 in this example is a speed limit at which the groundspeed limit should be enabled. In this example, constant 908 is 70 knots.
Groundspeed 906 and constant 908 are compared by comparator 911 . Comparator 911 determines whether groundspeed 906 is less than constant 908 . If groundspeed 906 is less than constant 908 , a true value is generated by comparator 911 and sent into AND gate 915 . If groundspeed 906 is not less than constant 908 , a false value is generated by comparator 911 and sent into AND gate 915 . AND gate 915 also receives groundspeed valid 904 and aircraft on ground 902 as inputs. The output of AND gate 915 is true if all of the inputs are true.
Airspeed 912 and constant 914 are sent into comparator 916 . In these examples, if airspeed 912 is greater than constant 914 , the output of comparator 916 is the logic “1.” This output is sent into AND gate 918 . AND gate 918 also receives airspeed valid 910 as an input. If the airspeed is valid and airspeed 912 is greater than constant 914 , a logic “1” is output by AND gate 918 . This output is sent into OR gate 920 . Additionally, the output of AND gate 915 is sent through inverter 922 into OR gate 920 . The output of OR gate 920 is sent into latch 922 .
Latch 922 also receives the output of AND gate 915 as an input. When the output of AND gate 915 is true, the output of latch 922 is set true, and remains true until the output of OR gate 920 is true. As long as the output of OR gate 920 is true, the output of latch 922 is false. The output of latch 922 forms groundspeed limit enable 924 , which is used in logic 800 . More specifically, groundspeed limit enable 924 is an example of groundspeed limit enable 806 in FIG. 8 .
In essence, groundspeed logic 900 determines whether the groundspeed limit is to be used. In these examples, logic 900 enables the groundspeed limit when the groundspeed is valid, the groundspeed is less than 70 knots, and the aircraft is on the ground.
Once logic 900 enables the groundspeed limit, this limit may be disabled if the groundspeed becomes invalid, the groundspeed exceeds 70 knots, the aircraft is in the air, or the airspeed is valid and the airspeed is greater than 50 knots. If the groundspeed limit has been disabled with speed that is above a selected level, or if the groundspeed is invalid, the groundspeed limit may be re-enabled. In this example, the disabling speed may be an airspeed of 50 knots and/or a groundspeed of 70 knots.
The groundspeed may be re-enabled if the commanded or requested thrust is less than the groundspeed limit for the current groundspeed, the groundspeed is valid, and the groundspeed falls below 20 knots.
With reference now to FIG. 10 , a diagram illustrating logic to generate an airspeed limit enable signal is depicted in accordance with an advantageous embodiment. In this example, logic 1001 receives a number of different inputs. These inputs include, for example, aircraft on ground 1000 , airspeed 1002 , constant 1004 , airspeed valid 1006 , groundspeed valid 1008 , groundspeed 1010 , and constant 1012 .
In this example, aircraft on ground 1000 is sent into latch 1014 . Airspeed 1002 and constant 1004 are sent to comparator 1016 . In this example, constant 1004 is 50 knots. If airspeed 1002 is greater than constant 1004 , a logic “1” is sent into AND gate 1018 . AND gate 1018 also receives airspeed valid 1006 as an input. The output of AND gate 1018 is sent into OR gate 1020 . Airspeed valid 1006 is sent through inverter 1022 to the input of AND gate 1024 . Groundspeed valid 1008 also forms an input into AND gate 1024 .
Groundspeed 1010 and constant 1012 are sent to comparator 1026 . In these examples, comparator 1026 determines whether groundspeed 1010 is less than constant 1012 . The output of comparator 1026 is sent through inverter 1027 to AND gate 1024 . The output of AND gate 1024 is sent to OR gate 1020 .
Aircraft on ground 1000 is also an input into OR gate 1020 . Aircraft on ground 1000 is sent through inverter 1026 into OR gate 1020 . If groundspeed 1010 is less than constant 1012 , the output of comparator 1026 is a logic “1” in these examples. Constant 1012 has a value of 70 knots in this example.
The output of OR gate 1020 is sent as an input into latch 1014 . The output of latch 1014 is set true when the aircraft is on the ground. When any of the input conditions cause the output of OR gate 1020 to be true, the output of latch 1014 is held false. The output of latch 1014 forms airspeed limit enable 1028 . This value is an input into logic 800 in FIG. 8 . Airspeed limit enable 1028 is an example of groundspeed limit enable 806 in FIG. 8 .
In this example, logic 1001 disables the airspeed limit when the airspeed is greater than 50 knots. The airspeed limit may be re-enabled in these examples, if the airspeed is less than 35 knots or if the airspeed is invalid and the groundspeed is valid and less than 20 knots, and if the commanded level thrust is less than the airspeed limit.
The logic illustrated in FIGS. 8-10 are provided as an example of one manner in which groundspeed and airspeed may be used to control thrust during takeoff. This example is not meant to imply physical or architectural limitations to the manner in which other advantageous embodiments may be implemented.
With reference now to FIG. 11 , a high level flowchart of a process for controlling thrust generated by an aircraft is depicted in accordance with an advantageous embodiment. The process illustrated in FIG. 11 may be implemented in thrust control process 402 in FIG. 4 .
The process begins by receiving a command for a desired level of thrust for an aircraft on the ground (operation 1100 ). The process sends the command to a thrust display (operation 1102 ). The thrust display in operation 1102 may be, for example, thrust display 312 in FIG. 3 .
The process controls a level of thrust actually provided by an engine in the aircraft based on a groundspeed and an airspeed (operation 1104 ), with the process terminating thereafter. Operation 1104 uses a lower limit of thrust set by a ground speed limit and an airspeed limit to control the level of thrust of the engine for the aircraft.
The level of thrust provided is based on the desired level of thrust and the lower limit, wherein the level of thrust is a continuous linear increase in thrust limited by the groundspeed limit and the airspeed limit. In other words, the level of thrust does not exceed the lower of the two limits as long as the limits are enabled or being used in the manner described in these examples.
With reference now to FIG. 12 , a flowchart of a process for controlling thrust generated by an aircraft is depicted in accordance with an advantageous embodiment. The process illustrated in FIG. 12 may be implemented in a software component such as, for example, thrust control process 402 in FIG. 4 . More specifically, FIG. 12 is a more detailed illustration of the process in FIG. 11 .
The process begins by receiving a command for a selected level of thrust for the aircraft (operation 1200 ). A determination is made as to whether a groundspeed limit has been enabled (operation 1202 ). If the groundspeed limit has been enabled, the thrust command is set using the groundspeed limit based on the current groundspeed (operation 1204 ), with the process terminating thereafter.
With reference again to step 1202 , if the groundspeed limit is not enabled, a determination is made as to whether an airspeed limit has been enabled (operation 1206 ). If the airspeed limit has been enabled, the thrust command is set using the airspeed limit based on the current airspeed (operation 1208 ), with the process terminating thereafter.
With reference again to operation 1206 , if the airspeed limit is not enabled, the process sets the thrust command as the received command (operation 1210 ), with the process terminating thereafter. In this case, the commanded thrust is the actual level of thrust that is sent as a thrust command to the engine. In operation 1210 , no limits are applied to the actual thrust since the groundspeed limit and the airspeed limit are not enabled.
With reference now to FIG. 13 , a flowchart of a process for enabling and disabling a groundspeed limit is depicted in accordance with an advantageous embodiment. The process illustrated in FIG. 13 may be implemented in a software component such as, for example, thrust control process 402 in FIG. 4 .
The process begins by determining whether the aircraft is on the ground (operation 1300 ). If the aircraft is not on the ground, the process disables the groundspeed limit (operation 1302 ). Next, the disable flag is set as true (operation 1304 ), with the process terminating thereafter.
With reference again to operation 1300 , if the aircraft is on the ground, a determination is made as to whether the disable flag is set equal to true (operation 1306 ). This determination is made to identify whether the groundspeed limit has been previously disabled, but may need to be re-enabled, for example if the aircraft has left the ground but returned to the ground.
If the disable flag is set equal to true, a determination is made as to whether the groundspeed is valid (operation 1308 ). If the groundspeed is not valid, the groundspeed limit is disabled (operation 1310 ) and the process sets the disable flag equal to true (operation 1312 ), with the process terminating thereafter.
With reference again to operation 1308 , if the groundspeed is valid, a determination is made as to whether the groundspeed is less than 20 knots (operation 1314 ). The threshold value of 20 knots is set at a speed that indicates that the aircraft is no longer taking off. In this case, the aircraft either was taking off and aborted the take off or took off and subsequently landed.
If the groundspeed is not less than 20 knots, the process proceeds to operation 1310 as described above. Otherwise, a determination is made as to whether the thrust is less than the thrust command (operation 1316 ). In this example, the thrust command is the command or desired thrust requested by pilot.
If the thrust is not less than the thrust command, the process proceeds to operation 1310 as previously described. Otherwise, the process re-enables the groundspeed limit (operation 1318 ). The process then sets the disable flag to false (operation 1320 ), with the process terminating thereafter.
With reference again to operation 1306 , if the disable flag is not true, a determination is made as to whether the airspeed is valid (operation 1322 ). If the airspeed is valid, a determination is made as to whether the airspeed is greater than 50 knots (operation 1324 ). If the airspeed is greater than 50 knots, the groundspeed limit is disabled (operation 1326 ). The process then sets the disable flag equal to true (operation 1328 ), with the process terminating thereafter.
With reference again to operation 1324 , if the airspeed is not greater than 50 knots, the groundspeed limit is enabled (operation 1330 ). The process then sets the disable flag equal to false (operation 1332 ), with the process terminating thereafter.
With reference again to operation 1322 , if the airspeed is not valid, a determination is made as to whether the groundspeed is valid (operation 1334 ). If the groundspeed is not valid, the process proceeds to operation 1326 as described above. If the groundspeed is valid, a determination is made as to whether the groundspeed is less than 70 knots (operation 1336 ).
In this example, the 70 knot groundspeed level provides a 20 knot margin above the airspeed limit of 50 knots. This margin allows for continuous engine acceleration for a takeoff in a 15-knot tailwind, as illustrated in FIG. 7 , and provides an additional 5 knot margin to account for uncertainty in the groundspeed sensing system. Of course, other thresholds may be selected depending on the implementation. If the groundspeed is not less than 70 knots, the process proceeds to operation 1326 . Otherwise, the process proceeds to operation 1330 as described above.
With reference now to FIG. 14 , a flowchart of a process for enabling and disabling an airspeed limit is depicted in accordance with an advantageous embodiment. The process illustrated in FIG. 14 may be implemented in a software component such as, for example, thrust control process 402 in FIG. 4 .
The process begins by determining whether the aircraft is on the ground (operation 1400 ). If the aircraft is not on the ground, the process disables the airspeed limit (operation 1402 ). The process then sets the disable flag equal to true (operation 1404 ), with the process terminating thereafter.
With reference again to operation 1400 , if the aircraft is on the ground, a determination is made as to whether the disable flag is set equal to true (operation 1406 ). If the disable flag is true, a determination is made as to whether the airspeed is valid (operation 1408 ). If the airspeed is valid, a determination is made as to whether the airspeed is less than 35 knots (operation 1410 ). If the airspeed is less than 35 knots, a determination is made as to whether the thrust is less than the thrust command (operation 1412 ). If the thrust is less than the thrust command, the process re-enables the airspeed limit (operation 1414 ) and sets the disable flag to false (operation 1416 ), with the process terminating thereafter.
In operation 1412 , if the thrust is not less than the thrust command, the process disables the airspeed limit (operation 1418 ) and sets the disable flag equal to true (operation 1420 ). With reference again to operation 1410 , if the airspeed is not less than 35 knots, the process also proceeds to operation 1418 .
In operation 1408 , if the airspeed is not valid, a determination is made as to whether the groundspeed is valid (operation 1422 ). If the groundspeed is valid, a determination is made as to whether the groundspeed is less than 20 knots. If the groundspeed is less than 20 knots, the process proceeds to operation 1412 as described above. Otherwise, the process proceeds to operation 1418 as previously described. In operation 1422 , the process proceeds to operation 1418 if the groundspeed is not valid.
With reference again to operation 1406 , if the disable flag is not true, a determination is made as to whether the airspeed is valid (operation 1426 ). If the airspeed is valid, a determination is made as to whether the airspeed is greater than 50 knots (operation 1428 ). If the airspeed is greater than 50 knots, the process disables the airspeed limit (operation 1430 ). The process then sets the disable flag equal to true (operation 1432 ), with the process terminating thereafter. As an example, the threshold of 50 knots may be the airspeed at which inlet separation due to crosswinds has been eliminated, and full thrust is allowed.
If the airspeed is not greater than 50, the process enables the airspeed limit (operation 1434 ). The process then sets the disable flag to false (operation 1436 ), with the process terminating thereafter.
With reference again to operation 1426 , if the airspeed is not valid, a determination is made as to whether the groundspeed is valid (operation 1438 ). If the groundspeed is valid, a determination is made as to whether the groundspeed is less than 70 knots (operation 1440 ). If the groundspeed is less than 70 knots, the process proceeds to operation 1434 as described above. The 70 knot groundspeed limit is selected to provide a margin above the 50 knot airspeed limit. Otherwise, the process proceeds to operation 1430 as previously described. The process also proceeds to operation 1430 in operation 1438 if the groundspeed is not valid.
The different thresholds illustrated in FIGS. 13 and 14 have been selected for purposes of depicting one implementation and are not meant to limit the manner in which other advantageous embodiments may be implemented. For example, in other advantageous embodiments, other groundspeed thresholds may be used other than those illustrated.
The flowcharts and block diagrams in the different depicted embodiments illustrate the architecture, functionality, and operation of some possible implementations of apparatus, methods and computer program products. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of computer usable or readable program code, which comprises one or more executable instructions for implementing the specified function or functions.
In some alternative implementations, the function or functions noted in the block may occur out of the order noted in the figures. For example, in some cases, two blocks shown in succession may be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved.
Thus, the different advantageous embodiments provide a method, apparatus, and program code for managing thrust levels in an aircraft. The different advantageous embodiments receive a command for a selected amount of thrust. The actual amount of thrust generated by the engine may be controlled based on the groundspeed and airspeed of the aircraft. In these different advantageous embodiments, an airspeed limit and a groundspeed limit may be applied to the received command to identify the actual command to be sent to the engine to generate thrust.
Using the different advantageous embodiments, an operator of the aircraft perceives a constant increase in thrust without reaching speed limits that may produce additional wear and tear on the engine. In particular, undesired vibrations on fan blades in the engine may be avoided to reduce the frequency of maintenance for these and other components.
The operator may only perceive a lag in engine thrust. As a result, the operator may not mistakenly perceive an anomaly in the engine requiring aborting the takeoff.
The different advantageous embodiments can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment containing both hardware and software elements. Some embodiments are implemented in software, which includes but is not limited to forms, such as, for example, firmware, resident software, and microcode.
Furthermore, the different embodiments can take the form of a computer program product accessible from a computer usable or computer readable medium providing program code for use by or in connection with a computer or any device or system that executes instructions. For the purposes of this disclosure, a computer usable or computer readable medium can generally be any tangible apparatus that can contain, store, communicate, propagate, or transport the program for use by or in connection with the instruction execution system, apparatus, or device.
The computer usable or computer readable medium can be, for example, without limitation an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, or a propagation medium. Non-limiting examples of a computer readable medium include a semiconductor or solid state memory, magnetic tape, a removable computer diskette, a random access memory (RAM), a read-only memory (ROM), a rigid magnetic disk, and an optical disk. Optical disks may include compact disk-read only memory (CD-ROM), compact disk-read/write (CD-R/W) and DVD.
Further, a computer usable or computer readable medium may contain or store a computer readable or usable program code such that when the computer readable or usable program code is executed on a computer, the execution of this computer readable or usable program code causes the computer to transmit another computer readable or usable program code over a communications link. This communications link may use a medium that is, for example without limitation, physical or wireless.
A data processing system suitable for storing and/or executing computer readable or computer usable program code will include one or more processors coupled directly or indirectly to memory elements through a communications fabric, such as a system bus. The memory elements may include local memory employed during actual execution of the program code, bulk storage, and cache memories which provide temporary storage of at least some computer readable or computer usable program code to reduce the number of times code may be retrieved from bulk storage during execution of the code.
Input/output or I/O devices can be coupled to the system either directly or through intervening I/O controllers. These devices may include, for example, without limitation, keyboards, touch screen displays, and pointing devices. Different communications adapters may also be coupled to the system to enable the data processing system to become coupled to other data processing systems or remote printers or storage devices through intervening private or public networks. Non-limiting examples are modems and network adapters are just a few of the currently available types of communications adapters.
The description of the different advantageous embodiments has been presented for purposes of illustration and description, and is not intended to be exhaustive or limited to the embodiments in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art. Further, different advantageous embodiments may provide different advantages as compared to other advantageous embodiments.
The embodiment or embodiments selected are chosen and described in order to best explain the principles of the embodiments, the practical application, and to enable others of ordinary skill in the art to understand the disclosure for various embodiments with various modifications as are suited to the particular use contemplated. | A method is presented for controlling thrust generated by aircraft engines. Engine thrust is controlled based on aircraft groundspeed and airspeed during the initial part of takeoff. Limiting thrust at low groundspeed during the initial phase of takeoff has significant benefits that reduce engine stress during this brief but critical phase leading to flight. Logical elements combine both groundspeed and airspeed in such a way that the operator perceives a smooth progressive thrust increase consistent with normal engine operation. | 52,766 |
FIELD OF THE INVENTION
[0001] This invention relates generally to animal controllers. More specifically, this invention pertains to a prod that controls animals with discharges of electrical energy.
BACKGROUND OF THE INVENTION
[0002] Devices that provide an electric shock to control behavior or movement of animals are well known. These devices, known as stock or cattle prods, are available in a variety of shapes and sizes and can be characterized in that they are able to control animals using high voltage electrical discharges. Generally, stock prods are hand held devices that comprise a housing that contains a power source, circuitry used to generate high voltage, and a pair of high voltage electrodes. The stock prod's power source is typically a dry-cell battery that is connected to an input of the circuitry used to generate the high voltage, with the high voltage generated by a step up transformer and/or a capacitor multiplier circuit. The high voltage output generated by the circuitry is typically connected to a pair of electrodes, which extend away from the exterior of the housing. Preferably, the electrodes are spaced apart from each other by a distance that is sufficient to prevent discharge therebetween. In use, the prod is activated to generate high voltage at the electrodes and the tips of the electrodes are brought into contact with, or in close proximity to, the skin of an animal. As the tips of the electrodes near or touch the animal's skin, the prod discharges leaving the animal with a gentle reminder that it should move or otherwise modify its behavior.
[0003] Present stock prods are designed to deliver each discharge as a steady or constant stream of high voltage oscillations or pulses having a predetermined intensity and duration. For example, a discharge may have an intensity of 10,000 volts at a frequency of 2,000 oscillations or pulses per second. It is important to note that the amount of energy expended with each discharge is directly related to battery life. For example, a prod having four C-cell batteries might be able to produce two hours of discharges before the prod loses its effectiveness, whereas a prod having six D-cell batteries might be able to produce three or more hours of discharges before the prod loses its effectiveness. It should be apparent, then, that with provision of additional and/or larger batteries the number of discharges that a prod is able to produce will increase accordingly and the life of the prod will be extended. The drawback with this approach, however, is that extra and/or larger batteries add weight and size to the prod and it eventually becomes too heavy and bulky to operate comfortably for extended periods of time. Alternatively, modifying the output of the prod's discharge can extend the battery life of a prod. There are several ways to do this.
[0004] One way is by reducing the duration of each oscillation or pulse. Another way is by lowering the voltage potential that is generated between the tips of the electrodes. In either case, the shock intensity felt by the animal is also reduced. As one may expect, the major drawback to employing such methods is that the increased battery life comes at the expense of operational effectiveness. This could be potentially life threatening, particularly when the operator is unable to administer an effective shock to a particularly large and/or agitated animal, or when an animal's skin is covered with a thick coat of hair.
[0005] Regardless of the particular way in which the battery life of a prod is extended, each time the prod is used, the batteries become weaker and the shock intensity diminishes. Eventually, there will be a point where the prod will no longer operate as intended. This is to be expected. The problem is that the battery life of the prod cannot be accurately predicted by merely observing the prod, and an operator has no way of knowing if the battery is capable of generating an hour's worth of discharges or is on the verge of failure. More often than not, the prod will suddenly go dead without any warning. This can be particularly dangerous, especially if the operator is in the midst of a herding operation involving scores of animals. There are several ways in which to prevent the occurrence of such a sudden and potentially catastrophic event.
[0006] One way is to periodically replace the batteries of the power source. This is very effective, but it can become quite costly if the batteries are frequently replaced, and it can be wasteful because perfectly good batteries may be thrown away and end up in a landfill. Moreover, it is not always possible to determine if the new batteries are themselves defective or substandard. That is, the batteries could be defective and fail prematurely. Another way to lessen the chance of having a sudden prod failure is to informally test the prod by creating a spark gap between the tips of the electrodes and observing the size of the high voltage arc and accompanying noise that is generated. The problem with this approach is that the inferences drawn from observing the spark are subjective. Moreover, the spark may be masked by bright daylight, accentuated by shadows, or skewed by variable atmospheric conditions such as high humidity, and the observer may overestimate or underestimate the operational capability and condition of the prod and it's battery life.
[0007] In a related matter, the above-mentioned stock prods are designed to operate at a given supply voltage, which may be based on the number of batteries used or based on a pre-engineered battery pack. So, for example, a prod may be designed to operate at six volts, nine volts, or in the case of a battery pack, fractional voltages such as seven and one-half volts. In either case, the stock prod's circuit is designed to draw a given amount of current for one particular supply voltage, resulting in a given battery life and given shock intensity. It is important to note that variations in the supply voltage and/or supply impedance can lead to variations in the supply current and variations in the discharge produced at the output end of the prod, which can affect the shock intensity and/or battery life of the prod. Such variations can be caused by changes in battery temperature, the configuration or size designation of the battery, and battery construction. Variability also exists between similarly sized batteries having different manufacturers.
[0008] The high voltage potential in present stock prods can be generated by several methods. One method is by using a step-up transformer, which typically comprises a primary (input) winding and a single secondary (output) winding, and has a core that is allowed to float (i.e., not connected to anything in an electrical sense). A drawback to such an arrangement is that electric fields and small amounts of leakage current can cause the core to be charged to an undesirable voltage potential that can lead to transformer failure. In an alternative configuration, the core may be connected to ground in the circuit, typically one of the secondary winding connections. A drawback with this arrangement is, relative to the grounded core, the non-grounded end of the secondary winding becomes charged to a voltage that is equivalent to the output of the prod, which can be around ten thousand volts or higher. This alternative configuration with the grounded core requires that the transformer be constructed with additional space between the grounded core and non-grounded end of the secondary winding to reduce electric fields that would otherwise lead to transformer failure. As will be appreciated, this can result in a larger stock prod housing.
[0009] The high voltage potential in present stock prods can also be generated using a capacitor multiplier circuit. Such circuits can be designed in several ways. A common circuit design uses a step-up transformer to drive the capacitor multiplier circuit where the transformer provides an increase in voltage over the supply voltage and the capacitor multiplier circuit steps up the transformer's output voltage to a high voltage potential. Although the transformer's voltage is lower than the high voltage potential, the transformer in this design may also suffer from the same electric field and leakage current as mentioned above. Alternatively, the circuit design may use transistors to drive the circuit. Unfortunately, the problem with such an arrangement is that without the transformer to provide an increase over the supply voltage, the multiplier circuit requires many more stages resulting in a design that is large and expensive. For this reason, this design is not common in the industry.
[0010] A common problem with the aforementioned high voltage generating configurations is that the high voltage can circumvent isolation between the various components and, under certain conditions, present a potential hazard to the operator. For instance, the operator may inadvertently become part of the electrical pathway when grabbing onto and holding a prod housing that is covered with condensation, or by accidentally touching an exposed metallic fastener that is in electrical contact with the power supply or primary circuit of the transformer of the prod, thus electrically connecting the user to the stock prod's power supply or primary circuit. In such not altogether uncommon conditions, should one of the electrode tips be brought into contact with an animal, current can flow out one of the high voltage electrodes, down through the animal, through the soil, up through the operator and back into the prod through the moisture or metallic fastener, and from the transformer's primary winding to secondary winding either through direction connection in the circuit or by arcing from primary winding to secondary winding, shocking the operator in the process. For this reason, some present stock prod enclosures try to provide the user with a layer of insulation to keep the user from becoming electrically connected to the power supply or primary circuit of the transformer.
[0011] Initially, electric stock prods were only able to produce one discharge level. However, it soon became apparent that one discharge level was not applicable to all animals. The problem was that some animals might be unaffected by the discharge, while other animals might find the shock intensity very intense. As a result, some of the present stock prods are now provided with a switch to change the shock intensity between two different discharge intensity levels or modes, high and low. Other stock prods are provided with interchangeable circuits or electrical generating components that provide predetermined levels of discharge intensity levels that are geared to the particular animal to be controlled. A drawback with these attempts to control the level of discharge intensity is that they are all preset by design and not adjustable, and the prod is unable to operate at an optimal level for a particular animal.
[0012] In addition to the high voltage, some stock prods are provided with an audible sound in an effort to control the animal more humanely. As one may imagine, this combination of a high voltage discharge and an audible sound may consume a relatively large amount of power. In an attempt to reduce such power consumption, some prods are provided with a second switch that can be used turn the high voltage off and conserve battery life. Typically, this second switch is located inside the battery compartment of the housing and is relatively difficult to access. This energy saving, high voltage cutout switch also allows the operator to control animals whose behavior has been modified to respond to the audible sound. However, the problem with this type of prod is that it does not give an operator the option of quickly reactivating the high voltage should a bull or other animal decide to charge.
[0013] Existing stock prod housings are manufactured using a variety of plastic materials to support the electrodes. Depending on the distance between the electrodes and the voltage differential therebetween, arcing may occur, and this often results in a layer of carbon being deposited across the housing surface. This carbon can cause the stock prod to short-out and stop providing a shock to an animal. One solution to this problem is to increase the space between the electrodes. Another solution to this problem is to reduce the voltage. The problem with these solutions is that they either increase size or reduce effectiveness and do not address the cause of carbon tracking, allowing the problem to reoccur.
[0014] There is a need for an electric prod that is able to extend battery life, while maintaining its effectiveness of operation. There is also a need for an electric prod that is less prone to accidental user shock, and transformer failure. There is yet another need for a stock prod that is able to maintain a predetermined output in the presence of different power supplies. There is also a need for a prod whose output intensity may be adjusted to a particular situation or a prod whose output self-adjusts to the situation. There is yet another need for a prod whose operational status is readily observable. There is still another need for prod that is able to provide two levels of animal control cues while the prod is in operation. And there is a need for a prod whose electrodes are less prone to short-circuiting.
SUMMARY OF THE INVENTION
[0015] Briefly, the present invention comprises an electric stock prod of the type that controls or modifies animal behavior through the use of multiple control cues, such as audible sounds and electrical discharges. The prod comprises a power module (or motor) having an input section, an output section, and a multi-functional control circuit. The input section of the power module (or motor) is operatively connected to a suitable power source and the output section of the power module is operatively connected to a pair of discharge electrodes. The power module is provided with a protective shell, which is positioned and secured within a prod housing. The power source may comprise one or more batteries, a battery pack, a fuel cell, or even a self-contained modular power unit, for example, and be positioned and secured within the prod housing or releasably attached to thereto, as the case may be. It will be appreciated that the output of the aforementioned power sources will vary in terms of operational voltage and impedance, and for that reason the prod of the present invention is provided with circuitry that is able to monitor the power source and control the output so that the prod can ultimately provide a consistent shock intensity. The circuitry also has the ability to assess the condition of the power source and transmit this information to the operator. A feature of the circuitry is that it is able to conserve power source life and still administer an effective electrical discharge to an animal. The intensity level of the electrical discharge can be further adjusted to take into account factors inherent to the animal being controlled, and/or external factors such as weather. Preferably, the prod is provided with a two-step trigger switch that is able to provide two control cues (an audio cue, and an electrical discharge cue) which are used to condition an animal and which also conserve energy. High voltage potentials are achieved through the use of a step-up transformer that is configured so that the potential for accidentally shocking the operator is greatly reduced.
[0016] More specifically, the stock prod of the present invention provides longer power source life by modifying the discharge of the prod without diminishing its effectiveness. This is achieved by forming each discharge into a series of short pulse trains instead of one long continuous pulse train or oscillations, and its operation may be described thusly: a short pulse train, then a pause with no pulses, then another short pulse train, then another pause with no pulses, and-so-on. Preferably, each of the shorter pulse trains has the same energy level per pulse and the same pulse rate as the longer continuous output. However, this can change depending on how the circuitry is programmed or configured. The benefits of having such a discharge are twofold. First, the prod is able to deliver a discharge that is as effective as a long pulse train. And second, by providing periods of acquiescence between the short pulse trains, power source life is prolonged. It will be appreciated that the parameters of operation such as energy level, pulse rate, periods of acquiescence between the pulses, etc. are values that may be programmed or otherwise incorporated into the circuitry design.
[0017] The step-up transformer of the present invention differs from prior art stock prods in that it has two secondary windings rather than one secondary winding. With this configuration, the two secondary windings are connected to each other in series, with one end of each winding connected as a center tap, which is connected to the transformer core. By using two secondary windings in series the voltage potential between the transformer's secondary winding can be halved, relative to the core. Thus, instead of having a ten thousand volt differential between a single secondary winding and the core, there are two voltage differentials of plus and minus five thousand volts between each of the two secondary windings and the core. Note that the voltage differential between those ends of the secondary windings not connected to the center tap would be equal to the output potential of the prod, in this example, ten thousand volts. This configuration allows the distance between the core and the windings to be reduced, resulting in a smaller, lighter, and less expensive transformer.
[0018] Another feature of the step-up transformer is that it also has an isolation value that has a higher value than the output voltage. By increasing the primary to secondary isolation such that the isolation is greater than the output voltage of the prod, the output voltage is prevented from jumping from the primary to the secondary winding to complete the circuit through an operator. This virtually eliminates any shock through an operator and the circuitry even if the operator is directly or indirectly in contact with the power source.
[0019] The circuitry of the prod performs several functions, one of which is to monitor the output of the power source. In operation, the circuitry compares the output of the power source with one or more predetermined values. Then depending on the degree of difference between the monitored and predetermined values, the circuitry will activate an indicator. For example, if the circuitry detects a level of supply current in the normal operating range, it will provide a signal to the operator of the prod. If the circuitry detects a level of supply current that is slightly below the normal operating range, but still able to produce an effective output, it will provide a different signal to the operator of the prod. And, if the circuitry detects a level of supply current that causes the output falls below a minimum threshold, it will provide yet another different signal. Thus the operator of the prod will be able to determine, in advance of use, if the power source needs to be immediately replaced or needs to be replaced in the near future. Preferably, the indicators are visually discernable when activated. However, it will be appreciated that they may produce sounds when activated, for example, pre-recorded messages, or tones.
[0020] Another function performed by the circuitry is to control the output or shock intensity. This is achieved using two different methods each independent from each another. In the first method, control is achieved by measuring the supply voltage of the power source to determine operational values. It will be appreciated that the operational values determine the output parameters of the output, such as voltage, number of pulses per second, and duration of pulse trains and duration between pulse trains. For example, four C-cell batteries combined to generate an output voltage of six volts will have a set of operational parameters different than the operational parameters for six C-cell batteries combined to generate an output voltage of nine volts. In each case, the combination of operational parameters and supply voltage will result in the same output parameters such as voltage, number of pulses per second, etc.
[0021] The second method to control the output or shock intensity is by measuring the supply current and comparing it to operational values that may be predetermined or generated according to the supply voltage. If there are differences between the measured and predetermined values, the output level of the power source is adjusted to bring it into accord with the predetermined value. For example, the circuit draws a given amount of current. The circuitry is designed so that it is able to measure this current draw and compare it to a predetermined value, say one amp, and adjust the output accordingly. Note that the operational values may be designed into, pre-programmed, or generated on a real-time basis by the circuitry as it measures the voltage value. As will be appreciated, this allows the prod to able to accommodate variations in power source impedance due to changes in temperature, changes in power source capacity, or with differences in impedances that occur in different brands of power sources, for example; without any appreciable change in performance. It also allows the prod to operate with different power sources having a range of operational voltages such as one or more batteries, a battery pack, or even a modular power unit having its own protective housing.
[0022] Additionally, the prod of the present invention is provided with a separate output adjuster with which to further vary the output level of the discharge. This gives an operator more control over the intensity of the shock that is delivered to an animal. Preferably, the variable output is achieved by providing the circuitry of the prod with a potentiometer. Thus, the prod is able to provide a range of shock intensity levels.
[0023] Advantageously, the stock prod is configured to be able to provide two distinct modes of operation. In the first mode, the stock prod will emit an audio cue. In the second mode, the stock prod will emit an audio cue and administer an electrical discharge. Thus, an operator can administer two types of control cues to an animal. In use, the operator of a prod will initially actuate the first mode of operation and then later progress to the second mode of operation so that an animal will receive an innocuous audio cue, and if necessary, an electrical discharge cue. As will be appreciated, actuating the two control cues may be accomplished in a number of ways and with a number of different switching arrangements, such as two separate switches or a single toggle switch. Preferably, however, the two modes of operation are controlled through one multi-step switch. And preferably, this multi-step switch is in the form of a two-step trigger switch. In order to activate the “audio only” first mode, the operator need only partially depress the trigger by a predetermined amount of movement. Note that in this mode, there will be no electrical discharge and this conserves battery life. In order to activate the second mode, which includes both audio and electrical cues, the trigger has to be depressed by a second, predetermined amount of movement.
[0024] Another feature of the present invention is that a portion of the power module housing between the discharge electrodes is provided with material that resists carbon tracking that would otherwise result in a carbon track and premature failure. Preferably, the material is polypropylene, and preferably the polypropylene is formed as a unitary structure such as an end cap, which receives and positions the discharge electrodes in a predetermined relation. It will be appreciated, however, that the polypropylene may take the form of a protective layer that is applied or attached to an end cap in a conventional manner.
[0025] Accordingly, an object of the present invention is to provide an electrically powered hand-held stock prod for controlling the movement and/or behavior of animals.
[0026] Another object of the invention is to increase the operational life of a prod without changing the effectiveness of its electrical discharge or shock intensity.
[0027] It is another object of the present invention to reduce the potential for user shock.
[0028] Yet another object of the invention is to facilitate determination of the operational status of a stock prod.
[0029] A feature of the present invention is that the input is monitored to control the output.
[0030] Another feature of the invention is that the prod may be powered by a variety of different sources having a range of voltage potentials.
[0031] Yet another feature of the present invention is that the operator may vary the shock intensity within a range of predetermined values.
[0032] Yet another feature of the present invention is that the shock intensity may be varied within a range of predetermined values by the control circuitry.
[0033] Still another feature of the invention is that the operational status of a prod may be visually ascertained.
[0034] Still another feature of the present invention is the ability to provide different levels and types of sensory cues for controlling the movement or behavior of animals.
[0035] An advantage of the present invention is that a prod is able to operate effectively using different power sources.
[0036] Another advantage of the invention is that the output may be tailored to a particular situation.
[0037] Still another advantage of the present invention is that a user can tell, at a glance, the operational status of a prod.
[0038] These and other objects, features and advantages of the present invention will become apparent from the following detailed description thereof taken in conjunction with the accompanying drawing, wherein like reference numerals designate like elements throughout the several views.
BRIEF DESCRIPTION OF THE DRAWINGS
[0039] [0039]FIG. 1 is a side plan view of a preferred embodiment of a stock prod;
[0040] [0040]FIG. 2 is a top plan view of the stock prod of FIG. 1;
[0041] [0041]FIG. 3 is a partial cross-sectional view of the stock prod of FIG. 1 taken along lines 3 - 3 ;
[0042] [0042]FIG. 4 is a cross-sectional view of the stock prod of FIG. 2 taken along lines 4 - 4 ;
[0043] [0043]FIG. 5 is a partial, exploded perspective view of a preferred housing and housing cover of a power supply for the stock prod of FIG. 1;
[0044] [0044]FIG. 6 is an isometric view of a preferred power module for the stock prod of FIG. 1;
[0045] [0045]FIG. 7 is an exploded view of the power module of FIG. 5;
[0046] [0046]FIG. 8 is a schematic representation of a preferred circuit used in the preferred stock prod of FIG. 1;
[0047] [0047]FIG. 9 is a partial top plan view of the circuit board illustrating the location of some of the components of the power module of FIG. 5; and,
[0048] [0048]FIG. 10 is a partial, isometric view of a preferred transformer used in the stock prod of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENT
[0049] Referring to FIG. 1, a preferred embodiment of a stock prod 10 is depicted. As can be seen, the stock prod 10 comprises an elongated body 12 having a first end 14 and a second end 16 . The first end 14 of the body 12 is operatively connected to a conventionally configured shaft 30 of the type having an attachment end 32 and a discharge end 34 , with the attachment end 32 includes a base 36 (see FIG. 3) and the discharge end 34 including electrodes 38 , 40 . The shaft 30 is operatively connected to the first end 14 of the body 12 by a ferrule 42 and a nut 44 . The second end 16 of the body 12 is operatively connected to a power supply 50 that comprises a housing 52 having a first end 54 , a second end 56 and a cavity 58 (see FIGS. 3 - 5 ). As can be seen, the first end 54 of the power supply 50 is operatively connected to the second end 16 of the body 12 in a manner that will be discussed later in greater detail. For ease of fabrication, body 12 is formed as housing members 18 , 20 which are removably connectable to each other in a confronting relation and which form an interior space 22 (see FIG. 5) that is configured to retain a power module 130 (see, for example, FIGS. 3, 6 and 7 ). As can be seen in FIG. 2, housing member 18 includes an aperture 88 that is configured to retain a protective lens 90 , which is positioned over a changeable indicator on the power module 130 (FIGS. 3, 6, and 7 ). As will be appreciated lens 90 may be clear or tinted as desired.
[0050] Referring to FIG. 3, the second housing member 20 includes a recess 92 and a peripheral wall 94 that are configured to receive a trigger assembly 100 . The trigger assembly 100 comprises a trigger housing 102 and a switch (or trigger) 108 that is pivotally connected to the housing 102 by a pivot pin 110 . The trigger assembly 100 is provided with a biasing element (not shown) that urges the switch 108 towards an off or non-engagement position. The assembly 100 also comprises a plunger 114 that is operatively connected to the switch 108 and which may be moved thereby into the interior 22 (shown in FIG. 5) of the body 12 through apertures 116 , 98 of the housing 102 and body 12 , respectively, so that it may engage an electrical contact 118 (see FIG. 6). Preferably, the trigger assembly 100 is attached to the housing member 20 by a fastener 106 that passes through apertures 96 and 104 of the body 12 and the housing 102 , respectively. The trigger assembly 100 also comprises a trigger lock 120 that is movably connected to the trigger switch 108 by a connecting member such as a pin fastener 122 . In order to lock the trigger switch 108 the trigger lock 120 , which is normally aligned with the trigger switch 108 , is rotated so that it is misaligned relative to the trigger switch 108 . When the trigger lock 120 is rotated in such a manner, the trigger lock is 120 is positioned so that it will contact the walls of the trigger housing 100 and/or the peripheral wall 94 of the housing member 20 . When this occurs, the trigger switch 108 and attached plunger 114 are prevented from moving the contact 118 (see FIG. 6) so that it completes an electrical circuit.
[0051] Turning to FIGS. 3 and 4, the shaft 30 is operatively connected to the first end 14 of the body 12 by a ferrule 42 that engages the base 36 of the shaft 30 , and a nut 44 that frictionally and compressively engages the ferrule 42 . Preferably, the nut 44 is threaded so that it may engage an end cap that extends beyond the first end 14 of the body 12 . Note that the electrical conduits of the shaft have been omitted since they do not form a part of this invention.
[0052] Referring to FIGS. 3 and 4, and the second end 56 of the housing 52 , note that the exterior surface of the base 60 is designed and configured so that it may support the stock prod 10 in a freestanding relation. As can be seen, the exterior surface of the base 60 is substantially planar. Preferably, the base 60 is provided with a stand-off or rib 62 that further positions the stock prod 10 and which provides clearance for a latch 74 that secures the housing 52 to the body 12 .
[0053] Referring to FIGS. 3 and 4, and the first end 54 of the housing 52 , note that the cavity 58 , which retainingly receives batteries B, may be closed off by a housing cover 76 . The cover 76 comprises a circumferential wall 78 that is configured to engage an internally formed ledge 59 in the power supply housing 52 . The cover also comprises resiliently mounted tabs 80 having outwardly extending projections 82 that engage inwardly facing recesses 61 (see FIG. 5) formed in the interior surface of the housing 52 . In an unstressed state, the tabs 80 are arranged so that the outwardly facing projections 82 are in position to engage the recesses 61 in the housing 52 . To disengage or attach the cover 76 to the housing 52 , the tabs 80 and their projections 82 are biased towards each other in a pinching action. Once the pinching action is discontinued, the tabs 80 are free to resume their unstressed state. The cover also comprises an aperture 84 (see FIG. 5) that is configured to accept a central shaft 64 that extends from the second end of the housing 52 . As can be seen, the central shaft 64 extends through the cavity 58 of the housing 52 and through the aperture 84 (see FIG. 5) of the cover 76 , but also partially though an aperture in the body 12 (see also FIG. 6). The central shaft 64 includes a through hole 66 that is configured to slidingly accept a rod 68 . One end of the rod 68 is threaded and provided with a nut 70 . The nut 70 is used to retain a deformable member 72 on the rod 68 so that it is positioned between the top of the end of the central shaft 64 and the nut 70 . The other end of the rod 68 is provided with a pivotly mounted latch 74 . The latch 74 is configured so that when it is aligned with the rod 68 the deformable member 72 is in an unstressed state, and when the latch 74 is pivoted so that it is transverse to the rod 68 the deformable member 72 is compressed and expands radially relative to the central shaft 64 and the aperture in the body 12 (see also, FIG. 6). Note that when the deformable member 72 is in its expanded state, it is larger than the aperture of the body 12 , and withdrawal of the central shaft 64 therefrom is prevented.
[0054] Referring to FIG. 5, the juxtaposition of a power supply housing 52 , a housing cover 76 and a body 12 can be seen. Assembly is a follows. A cover 76 is positioned over the first end 54 of the housing 52 . Note that batteries have been omitted from the cavity 58 of the housing 52 to facilitate a better understanding of the figure. The tabs 80 are then moved towards each other in a pinching action and the aperture 84 of the cover 76 is aligned with the central shaft 64 . The cover 76 is then slid over the central shaft 64 until the circumferential wall 78 engages the ledge 59 of the housing. Since the depth of the circumferential wall 78 of the cover 76 is less than the depth of the ledge 59 of the housing 52 , the cover 76 will be recessed relative the edge of the first end 54 . The tabs 80 are then released and the projections 82 are allowed to engage the recesses 61 of the housing. To attach the power supply housing 52 to the body 12 , the first end 54 of the housing is brought into alignment with the second end 16 of the body 12 . The housing 52 and the body 12 are then brought together. As the housing 52 and the body 12 are brought together, offset skirts 24 a , 24 b guide their movements until the housing 52 contacts shoulders 26 a , 26 b of the body. As this occurs, the deformable member 72 of the central shaft 64 protrudes through an attachment aperture in the body (see FIG. 6). After the housing 52 and the body 12 have been joined together, the latch 74 (see FIG. 3) is pivoted so that it is transverse to the rod 68 . This causes the deformable member 72 to expand and prevent the central shaft 64 from being withdrawn from the engagement with the aperture in the body. It will be appreciated that the cover 76 need not be present for the power supply housing 52 to be connected to the body 12 , and that there may be occasions where such a connection will be necessary or desirable.
[0055] Referring to FIG. 6, the body 12 (as shown in FIG. 1) is configured to retain a power module 130 comprising a shell 132 having opposing helves 134 , 136 (see FIG. 7). The shell 132 has a first end 138 and a second end 140 . The second end 140 comprises an aperture 144 that is configured to admit the nut 70 and the deformable member 72 of the central shaft 64 that extends from the base 60 of the power supply housing 52 . The second end 140 also comprises a second aperture 142 that is configured to permit manipulation of an output adjustment member. The second end 140 also comprises an input section 146 which operatively connects to the power supply 50 through the electrical interface 86 (see FIG. 5) of the housing cover 76 of the power supply housing 52 . As will be seen, the input section 146 distributes power to several areas of the power module 130 . Continuing on, the first end 138 comprises a threaded end cap 150 that forms a portion of the output section 152 , which partially extends from the shell 132 .
[0056] Referring to FIG. 7, the shell halves 134 , 136 have been separated to reveal internal components of the power module 130 . As can be seen, the shell halves 134 , 136 form an aperture 154 at the first end 138 that receives the end cap 150 . The end cap 150 comprises a plurality of tabs 156 ( a - d ) that are configured to be received in slots 158 ( a - d ) in the shell halves 134 , 136 during assembly of the shell 132 . The end cap 150 includes two apertures 160 , 162 that are configured to receive and retain connectors J 5 , J 4 , respectively, that conduct electricity to the shaft 30 (see also, FIG. 4). The end cap 150 is fabricated from material that resists carbon tracking. Preferably, the material comprises polypropylene. It is understood, however that other material having similar characteristics may also be used. It is also understood that the end cap need not be fabricated as a unitary structure, and that carbon tracking resistant material may be applied to the end cap in a conventional manner using known techniques and technologies. The internal components of the power module 130 are carried on a printed circuit board 170 whose circuitry will be discussed in greater detail below.
[0057] Referring to FIGS. 8 and 9, a preferred circuit diagram of a stock prod in accordance with the present invention is shown. The power supply circuit is powered by a suitable direct current power supply, which may be take the form of four to seven batteries providing six to nine volts DC. The circuit is connected to the power supply by through connectors J 1 and J 2 , where J 1 and J 2 are positive and negative, respectively.
[0058] Power from the power supply is connected to three sections of the circuit in FIG. 8. First, power is connected to the voltage sense circuit comprised of zener diode D 3 used to create an offset voltage and resistor R 3 B and resistor R 4 C configured in what is commonly referred to as a voltage divider. Voltage at the common point of resistor R 3 B/R 4 C is connected to the control circuit through resistor R 4 B provided as a high impedance between the voltage divider and the control circuit. The voltage sense circuit provides the control circuit with measurable voltage reflective of the power supply voltage.
[0059] Second, power is connected to transformer T 1 through diode D 1 and capacitor C 1 . Transformer T 1 is used to generate high voltage and is turned on and off by a transistor Q 1 which is connected to the control circuit. When transformer T 1 is turned on (on-time), current flows through the primary winding storing energy in the transformer's core. When transformer T 1 is turned off (off-time), energy in the core is coupled to the secondary winding of Transformer T 1 creating a high voltage pulse. The on-time and off-time are critical to both the prod's shock intensity and power supply life and are an intricate part of the timing circuit covered later. Current provided to transformer T 1 is provided through diode D 1 , which is used to prevent current flow should the power supply be connected with the incorrect polarity. Current provided to transformer T 1 is also provided through capacitor C 1 , which is used as a filter to provide a more constant current flow from the power supply.
[0060] Third, power is connected to the power supply for the control circuit and is comprises a voltage regulator U 1 , capacitors C 2 , C 3 , and C 4 and diode D 2 . Voltage regulator U 1 provides a constant voltage for the control circuit and serves as a reference voltage. Capacitors C 2 , C 3 , and C 4 all provide filtering for electrical noise. Diode D 2 is used to prevent current flow from the power supply to the control circuit should the power supply be connected with the incorrect polarity. The control circuit consists of a single part, micro-controller U 2 . Micro-controller U 2 performs all measurements, provides all timing functions, determines all operating values, and controls functions of the stock prod. When power is applied to the circuit shown in FIG. 8, micro-controller U 2 starts executing it's program and measures the voltage from the voltage sense circuit comprised of Diode D 3 and Resistors R 3 B, R 4 C, and R 4 B through an internal A/D converter connected to pin 6 of Micro-controller U 2 . The voltage measured by micro-controller U 2 at pin 6 is directly related to the supply voltage. The program executed in micro-controller U 2 compares the measured voltage to predetermined values to determine the voltage of the power source and sets additional operating parameters based on the operating voltage. The step of setting operating parameters for variation in supply voltage allows the stock prod's shock intensity and power supply life to be kept constant regardless of supply voltage.
[0061] Once the voltage of the power supply is determined and micro-controller U 2 determines the operating parameters for given supply voltage, micro-controller U 2 executes program code to determine the position of the trigger (or switch, see 108 of FIG. 3). The trigger is provided with three positions. The first position is off with connector J 3 connected to the negative supply contact, connector J 2 . When the trigger is partially pressed, power is applied to the circuit through connector J 2 and J 1 . As the trigger is further pressed to the third position, connector J 3 is disconnected from ground (Connector J 2 ). Micro-controller U 2 measures the voltage on connector J 3 through resistor R 3 A by means of another A/D converter connected to pin 5 . R 3 A is provided to allow micro-controller pin 5 to operate as an output while connector J 3 is connected to ground. If the voltage measured by micro-controller U 2 at pin 5 is connected to ground, the program changes pins 5 and 6 to outputs to drive an annunciator (preferably a buzzer) B 1 . The program remains in a loop measuring the position of the trigger based on the voltage at pin 5 and toggles outputs from pins 3 , 5 , and 6 to create an audio sound from the annunciator (buzzer) B 1 and to create a signal from an indicator of an indicator circuit (wherein the indicator circuit preferably comprises a light emitting diode (LED) D 5 and current limiting resistor R 2 ). When the trigger is fully pressed, the voltage at pin 5 rises above ground allowing micro-controller U 2 to measure the increase in voltage causing the program to move to the section of program code used to generate high voltage at the prod's output connectors J 4 and J 5 . This three-stage trigger allows the user to activate the prod in either audio only or in high voltage modes without the use of a second switch located in an inconvenient location.
[0062] Before turning the high voltage on, micro-controller U 2 executes a section of program to determine the output level according to where the user sets the position of an output adjuster (preferably a potentiometer) R 7 . The potentiometer R 7 is connected to ground and in series with resistors R 5 C and R 5 B where resistor R 5 B becomes the upper leg of a voltage divider. Resistors R 7 and R 5 C become the adjustable lower leg of the voltage divider, and common point of the voltage divider (R 5 B and R 5 C) is measured by micro-controller U 2 through the A/D converter connected to pin 5 . Based on the voltage measured by micro-controller U 2 at pin 5 , parameters are determined for the output of the prod. As long as the high voltage is on, micro-controller U 2 will loop back to this section of the program, determine position of potentiometer R 7 , and adjust the parameters for the output based on the position of potentiometer R 7 .
[0063] After micro-controller U 2 has executed the section of program to determine the user's desired output level according to the position of the output adjuster R 7 , micro-controller U 2 provides a signal to transistor Q 1 turning current on to the primary winding of transformer T 1 . The gate of transistor Q 1 is also connected through resistor R 3 C to ground to bleed off any gate charge on transistor Q 1 . When transistor Q 1 is turned on and current flows from the positive supply source connected to connector J 1 , through diode D 1 , through the primary winding of transformer T 1 , through transistor Q 1 , and through resistor R 1 to ground connected to connector J 2 . Resistor R 1 is provided in the lower leg of the current path to provide a voltage level that changes relative to ground with the amount of current through the primary winding of transformer T 1 . Resistor R 1 is also provided in parallel with capacitor C 6 provided for noise suppression. As current through transformer T 1 increases during the current pulse, the voltage across resistor R 1 increases. The voltage across resistor R 1 is measured by micro-controller U 2 through another A/D converter located within micro-controller U 2 at pin 7 through Resistor R 4 A. Resistor R 4 A is provided just as in impedance between micro-controller U 2 and the rest of the circuit for purposes of noise rejection. After determining the current through the primary winding of transformer T 1 by means of the voltage across resistor R 1 , micro-controller U 2 compares the current to operating parameters to determine if the current is within limits. If the parameters are not within limits, micro-controller U 2 adjusts the on-time duration to move the current back within limits. This allows the prod to compensate for changes in power supply due to factors such as aging or temperature (ie. old and/or cold batteries).
[0064] As micro-controller U 2 determines the supply current by measuring the voltage across resistor R 1 , it also determines if the current can be maintained within limits, maintained out of limits, or inadequate for the prod to deliver an effective output. If the current can be maintained within limits, micro-controller U 2 sets outputs at pins 3 and 5 to turn the indicator on to a predetermined color (ie. turning the LED D 5 on green) to provide a signal to the user that the power source is acceptable. If the current can be maintained but not within limits, micro-controller U 2 sets outputs at pins 3 and 5 to turn the indicator on to a second predetermined color (ie. turning the LED D 5 on yellow) to provide a signal to the user that the power source is weak. If the current is determined to be inadequate to provide an effective output, micro-controller U 2 sets outputs at pins 3 and 5 to turn the indicator on to a third predetermined color (ie. turning the LED D 5 on red) to provide a signal to the user that the power source is unacceptable. This provides the user with immediate feedback regarding the condition of the power source.
[0065] Micro-controller U 2 continues executing it's program turning transformer T 1 on and off by transistor Q 1 , while determining the supply current by measuring the voltage across resistor R 1 , determining the user's desired output according to the position of output adjuster (potentiometer) R 7 , controlling the type of signal that the indicator displays to the user through diode D 5 according to the condition of the power source, and adjusting operating parameters, limits, and variables to maintain a constant output. After continuing operation for two seconds, micro-controller U 2 tests pin 4 to determine if it is connected to ground, or if the ground has been removed at the factory where resistor R 5 A connected between micro-controller pin 4 and Vdd pulls pin 4 above ground. If micro-controller U 2 determines pin 4 is connected to ground, the program continues in the same loop described above. If micro-controller U 2 determines pin 4 is no longer connected to ground, transistor Q 1 is turned off and held off until the user releases the trigger and reapplies power causing micro-controller U 2 to restart at the beginning of it's program. This determination of the condition of micro-controller U 2 pin 4 allows the program to operate in more than one mode; for example, when continuous operation is desired, or when operation is stopped after a predetermined period of time (for example, two seconds).
[0066] While micro-controller U 2 turns transformer T 1 on and off, off-times are periodically extended creating pulse trains and periods with no output. The shock intensity felt during the pulse train is the same as if no off-time had been extended. Although no shock is felt during the time of the extended off-time, the prod is as effective during the pulse train. This extended off-time reduces the average current draw from the power source, which results in longer power supply life
[0067] As the current is turned on and off through the primary winding of transformer T 1 , high voltage pulses are developed on the secondary winding. These pulses are rectified through diode D 4 and stored in capacitor C 5 until the voltage in capacitor C 5 is high enough to break down spark gap JP 1 . Capacitor C 5 is provided with a resistor R 6 in parallel to bleed capacitor C 5 down after power has been removed from the circuit to avoid capacitor C 5 from retaining a charge possibly discharging accidentally several seconds after the user releases the trigger. When the voltage in capacitor C 5 breaks down spark gap JP 1 and when the high voltage connectors J 4 and J 5 are in contact with an animal, the energy in capacitor C 5 discharges through the animal administering the shock. A discharge may also occur when the voltage in capacitor C 5 breaks down spark gap JP 1 and when a path such as a carbon track is provided between connectors J 4 and J 5 . To reduce and/or eliminate the possibility of a carbon track developing, an insulator manufactured of polypropylene, which resists carbon track build up, supports connectors J 4 and J 5 .
[0068] In addition to providing the high voltage, transformer T 1 also provides isolation between the power source connected to the primary circuit and the secondary winding connected to the high voltage circuit. The isolation is different from existing stock prod transformers in that the isolation between primary winding and the secondary winding is higher than high voltage potential delivered. This higher level of isolation between primary and secondary winding creates an insulation barrier such that the user is isolated form the high voltage eliminating the possibility of the user receiving a shock through moisture connecting the user to the supply source or primary circuit.
[0069] Referring to FIG. 10, transformer T 1 is depicted without windings to better facilitate understanding of the invention. As can be seen the transformer T 1 comprises a generally u-shaped core 180 having legs 182 and 184 . Starting from the left side of the figure, a primary winding connector 188 can be seen. A primary winding bay 190 and a second primary winging connector 192 and one or more isolation members 194 follow this. As mentioned previously, the transformer of the present invention differs from transformers used in prior art stock prods in that it has two secondary windings rather than one secondary winding. Moreover, the secondary windings are connected to each other in series. Thus, the first of the two secondary windings starts with secondary center tap 202 , proceeds to secondary winding bays 200 and 196 , and ends up at negative secondary winding connection 198 . The second of the two secondary windings starts with the secondary center tap 202 , proceeds to a secondary winding bays 204 and 208 and attaches to a positive secondary winding connection 206 . With this configuration, the two secondary windings are connected to each other in series, with one end of each winding connected at a center tap 202 , which is connected to the transformer core 180 . By using two secondary windings in series the voltage potential between the transformer's secondary winding can be halved, relative to the core.
[0070] The present invention having thus been described, other modifications, alterations or substitutions may present themselves to those skilled in the art, all of which are within the spirit and scope of the present invention. It is therefore intended that the present invention be limited in scope only by the claims attached below. | An electrical discharge stock prod having a circuit that prolongs battery life by monitoring power input and modifying the prod discharge characteristics. The circuit allows the prod to deliver a consistent voltage level to discharge electrodes, even though the power sources may vary. Preferably, the circuit is operated by a micro-controller. Additionally, by virtue of an improved transformer configuration (which lowers the voltage potential between the primary and secondary cores) and strategically placed polypropylene (which reduces carbon arcing) and increased isolation between primary and secondary windings within the transformer, safety of the prod is substantially enhanced. Preferably, the voltage to the discharge electrodes of the prod can be infinitely adjusted within a predetermined range of voltages, energies, and/or pulse rates to allow the prod to be effectively used on subjects having different physical parameters. Moreover, the prod is provided with a multi-function actuator that is configured to provide the prod with two types of cues; an audible cue, and a combined audible and electrical discharge cue, respectively. The prod includes a visual indicator that lets the operator know, at a glance, if the power supply has sufficient energy to operate the prod. And, the prod includes a removable power unit that includes a base, which enables the prod to be free standing when not in use. | 54,885 |
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a method for monitoring the functional capability of lambda sensors, in which switching times of the lambda sensor are measured.
In internal combustion engines, pollutant emissions can be reduced by catalytic post-treatment.
A prerequisite of catalytic post-treatment is a certain composition of the exhaust gas, which is known as a stoichiometric mixture. That purpose is served by mixture regulation by means of a so-called lambda sensor, by which the mixture composition is periodically regulated within close limits around a command or setpoint value. To that end, if the fuel/air mixture is rich, the sensor outputs a high voltage (the rich voltage), and if the fuel/air mixture is lean, it outputs a low voltage. A voltage jump that is characteristic for lambda=1 is located between those voltages.
The sensors may become defective in the course of operation, causing the mixture composition to be incorrectly regulated. In that case the exhaust gases are no longer correctly detoxified, and over the long term the catalyst is even damaged as a result.
It is therefore necessary to monitor the functional capability of the lambda sensor.
Summary of the Invention
It is accordingly an object of the invention to provide a method for monitoring lambda sensors, which overcomes the hereinafore-mentioned disadvantages of the heretofore-known methods of this general type and which makes it possible to reliably monitor a dynamic functional capability of a lambda sensor.
With the foregoing and other objects in view there is provided, in accordance with the invention, a method for monitoring lambda sensors, which comprises ascertaining a reference value from a magnitude of switching times under operating conditions of a lambda regulation cycle, in which a sensor signal changes from a rich value to a lean value or from a lean value to a rich value, and classifying a sensor as functioning correctly if the reference value is less than an associated limit value.
This is done by measuring the switching times within which the lambda sensor, in the context of its jump function, switches over from the high voltage value (rich voltage) that characterizes a rich mixture to a lower voltage value (lean voltage) that indicates a lean mixture. The switching times for the reverse jump from "lean" to "rich" are also measured. The magnitude of these switching times is a measure of the functional capability of the lambda sensor. If the switching times are above a limit value ascertained beforehand on a test bench using correct lambda sensors, or if they are equivalent to this limit value, the lambda sensor is defective. If the switching times are below the limit value, then the lambda sensor is functioning correctly. The limit values are dependent on the engine operating point and are therefore taken from a performance graph, for instance as a function of the aspirated air and the rpm of the engine.
In order to monitor the switching times, it is necessary for the engine to be in a virtually steady operating state during the test cycle. However, in that state, the testing is possible without disruptively intervening in the lambda regulation.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a method for monitoring lambda sensors, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
The drawing is a flow chart which shows the course of an exemplary embodiment of the method according to the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the single FIGURE of the drawing in detail, there is seen an exemplary embodiment in which it is assumed that with a rich mixture, a lambda sensor outputs a higher voltage value than with a lean mixture. The method of the invention functions analogously with lambda sensors which have the opposite relationship between the voltage and the mixture.
According to the invention, a reference value is ascertained from lambda sensor switching times. In the exemplary embodiment, a plurality of switching times are added together for that purpose, with a separate evaluation being made of the switching times from rich to lean and from lean to rich, and they are compared with an associated limit value.
In a method step S1 a switching time TS that the lambda sensor requires to switch over from rich to lean or from lean to rich, is measured.
By way of example, the measurement may be performed with a clocked time counter. At the switchover from rich to lean, the elapsed-time counter remains at zero as long as the lambda sensor signal is above a rich threshold.
If it drops below the rich threshold, then the time counter begins to run. It stops again once the lambda sensor signal has dropped below the lean threshold.
At the switchover from lean to rich, the elapsed-time counter remains at zero as long as the lambda sensor signal is below the lean threshold.
If it rises above the lean threshold, then the time counter begins to run. It stops again when the lambda sensor signal rises above the rich threshold. A predeterminable fraction of the maximum value of the lambda sensor signal is defined as the rich and lean thresholds. For instance, 90% of the maximum value is assumed as the rich threshold, and 10% of the maximum value is assumed as the lean threshold. Instead of the most recent measured individual maximum value or minimum value, it is also possible to use the value obtained through a sliding averaging from the respective last actually measured values.
As is indicated in a method step S2, the switchover event is monitored at turning points. A turning point occurs if in the event of switching from rich to lean the actually steadily diminishing lambda sensor signal suddenly becomes larger again, or in the event of switching from lean to rich, the actually steadily increasing lambda sensor signal suddenly becomes smaller again. If a turning point is thus recognized, this switching time is no longer used for evaluation.
In a method step S3, monitoring is carried out as to whether or not the engine is in a virtually steady state, that is whether or not the load and rpm have not varied considerably since the last switching time measurement. If such an approximately steady state is not present, then once again the switching time is not used for evaluation.
However, if an approximately steady state is indeed present, then in a method step S4 a check is made as to whether or not the sensor is switching from rich to lean, and if so then a jump is made to a step S5, or if it is switching from lean to rich, in which case a jump is made to a step S9.
In the method step S5, the currently ascertained switching time TS is added to a sum SFM of the switching times that were already ascertained previously.
Then in a method step S6, a switching time limit value FMG is read out from a performance graph, for instance as a function of an aspirated airflow and an rpm of the engine, and is added to a sum SFMG of previously already read-out limit values.
In a method step S7, a counter ZF, which indicates the number of switchovers from rich to lean, is incremented by one.
In a method step S8, a check is made as to whether or not the value of the counter ZF is less than a predeterminable trip value ZFA that defines the length of the test cycle. If that is the case, then a return is made to the start of the method. However, if the value is greater than or equal to the trip value, then in a method step S14 a check is made as to whether or not the sum of ascertained switching times SFM from rich to lean is less than the limit value SFMG. If so, then in a method step S16 an indication is issued that the lambda sensor is functioning properly. However, if the ascertained total value SFM is greater than or equal to the limit value SFMG, then in a method step S15 an indication is made that the lambda sensor is defective.
In both cases, the counters and summands are reset in a method step S17, and then if new monitoring of the lambda sensor is intended to take place, a return to the start of the method is made.
Conversely, if it is found in the method step S4 that the sensor is switching from lean to rich, then a jump is made to a method step S9.
In the method step S9, the currently ascertained switching time TS is added to the sum SMF of switching times that were already ascertained previously.
Then in a method step S10, the switching time limit value MFG is read out from a performance graph, again as a function of the current operating conditions of the engine (for instance from the aspirated air mass and the current rpm), and is added to the total SMFG of previously already read-out limit values.
In a method step S11, the counter ZM, which indicates the number of switchovers from rich to lean, is incremented by one.
In a method step S12, a check is made as to whether or not the value of the counter ZM is less than a trip value ZMA. If that is the case, then a return is made to the start of the method. However, if the value is greater than or equal to the trip value, then in a method step S13 a check is made as to whether or not the sum of ascertained switching times SMF from lean to rich is less than the limit value SMFG. If so, then as was already described above, in the method step S16 an indication is issued that the lambda sensor is functioning properly. However, if the ascertained total value is greater than or equal to the limit value, then as was already described above, in the method step S15 an indication is made that the lambda sensor is defective.
If the lambda sensor is defective, a monitoring of catalyst efficiency, which may possibly be present, is moreover inhibited. | A method for monitoring lambda sensors includes ascertaining a reference value from a magnitude of switching times under operating conditions of a lambda regulation cycle, in which a sensor signal changes from a rich value to a lean value or from a lean value to a rich value. A sensor is classified as functioning correctly if the reference value is less than an associated limit value. | 10,593 |
BACKGROUND
1. Field of the Invention
This invention relates to processes for selectively separating a mixture of components through sorption and desorption and, more particularly to a novel simulated moving bed apparatus and method whereby the simulated moving bed is created within an uninterrupted sorbent bed by imbedding strategically within such sorbent bed multiple distributors for injection of feedstock and eluent along with multiple collectors for removal of extract and raffinate and to obtain narrower fraction cuts by reducing the time for injecting feedstock and eluent and collecting separated fractions respectively without stopping the percolation of circulating fluid through the sorbent bed which results in significantly reduced bed compaction and flow restriction.
2. The Prior Art
The commercial application of column chromatography for the separation of dissolved constituents using suitable sorbents and batch operation has evolved over the years to a level as represented by Yoritomi et al (U.S. Pat. Nos. 4,379,751 and 4,267,054). To achieve a reasonable level of separation the sorbent beds in these systems must be relatively tall. Yoritomi specifies at least 10 meters. At such high bed depths the flow rates through the bed must be relatively low to avoid progressive bed compaction and eventual total blockage to flow. These necessary low flow rates restrict operating capacities which could potentially be available from state of the art, high kinetic separating mediums. The stop and go operation of a batch process as represented by U.S. Pat. No. 4,379,751 also leaves a large part of the separating medium idle in certain parts of the column while feedstock and eluent are added to the column or extract and raffinate fractions are withdrawn. Additionally, the total removal of certain concentration bands from the column liquid as practiced by U.S. Pat. No. 4,379,751 imposes rather sudden changes of concentration gradients which impairs general operating efficiency in terms of osmotic shock on the resin and the need to re-establish this concentration band in subsequent cycles which retards the speed of operation. These impediments have all but eliminated the batch process from consideration for commercial application in column chromatography.
The invention of the so-called simulated moving bed process by Broughton et al (U.S. Pat. No. 2,985,589) improves on the batch operation in its most sophisticated form by providing for the continuous circulation of fluids through multiple beds of sorbents. The sorbent beds are arranged as an endless loop with periodic advances to the next sorbent bed within the loop for inlet flows of feedstock and eluent and outlet flows of effluent fractions, respectively. This operation is also referred to as a pseudo moving bed process. One form of commercialization of this process includes discrete multiple sorbent beds vertically stacked on top of each other in the form of a tower as initially proposed by the foregoing reference as well as those of Ishikawa et al (U.S. Pat. No. 4,182,633); Odawara et al (U.S. Pat. No. 4,157,267); Ando et al (U.S. Pat. No. 4,405,455). Another approach is the use of multiple individual columns horizontally arranged as a train with the train operated as an independent closed loop and is taught by Schoenrock et al (U.S. Pat. No. 4,412,866) and Ando et a (U.S. Pat. No. 4,599,115). In the commercial separation of dissolved constituents by chromatography such a the fractionation of fructose from dextrose or the separation of sucrose from highly impure sugar solution such as molasses by ionic exclusion using the so-called simulated moving bed technique, it becomes necessary to establish and maintain a very specific concentration profile. This concentration profile is distributed, as a rule, over four or more sorbent beds as taught by the foregoing references to aid in optimizing the introduction and withdrawal of streams at strategic positions of the closed loop.
One or more of these sorbent beds within the endless loop is projected to represent a specific zone which in their most fundamental form are referred to as sorption, displacement, elution and rinse zones, respectively. Continuous circulation of the loop fluid around this endless loop train causes each of the zones to be periodically shifted to the sorbent bed next in line downstream. The objective is t maintain a steady state concentration profile which moves as a wave continuously around the looped train while introducing feedstock and eluent to the train at strategic locations and removing separated fractions from the circulation fluid thereby establishing a continuum.
General performance efficiency and steady state operation of the process depend primarily upon the following factors:
1. Accurate control of the correct circulating flow to maintain a steady state profile through the entire loop.
2. Correct selection of influent and effluent cuts.
3. Uniform cross sectional distribution and drainage of fluids entering and leaving the beds, respectively.
4. Uniform cross sectional, downward movement of the circulation fluid through the sorbent beds with avoidance of channeling or net lateral flow.
5. Distinction between hydraulic balance and internally generated pressure through the circulation pumps and separate control for each pressure function.
Conventionally the determination and control of the circulation flow rate remains generally undefined and left to speculation or experimentation. The patent of Schoenrock et al refers to a total liquid displacement volume as being given to provide the basis for establishing the circulation flow rate without defining the meaning of that terminology or how one arrives at that value. Other patents are mute on this point and leave the impression that this value is derived through trial and error. Although the teachings of U.S. Pat. No. 4,412,866 are very specific for correcting a given basic circulation flow rate with measured inflow and outflow rates, experience has shown that these corrections are not accurate and ineffective if the basic circulation flow rate is not accurately know.. The foregoing problems reduce the operating efficiency and the need for periodic manual corrections of the circulation flow rate. Because of its dynamic nature the pseudo-moving bed operation of the known prior art generates a continuously changing concentration profile of the dissolved components in the fluid percolating through the sorbent beds in terms of absolute concentration as well as the relative concentration of the dissolved solutes to each other.
These systems also teach and practice a continuous inflow of feedstock and eluent and respective outflows of separated fractions throughout the complete cycle This constraint requires compromises for selecting the positions to introduce feedstock and eluent as well as for withdrawing effluent fractions. A constant feedstock and eluent composition is thus introduced into and spread over a continuously changing concentration profile in the circulation fluid while continuously changing effluent concentrations are withdrawn. Such a processing strategy compromises the background concentration profile. Continuous or frequent monitoring of these concentration profiles is therefore essential to bracket the target concentrations for inlet and outlet positions in pseudo-moving bed separator loops to approach optimum operating performance for the system. To overcome this impediment it is common practice to increase the number of sorbent beds within a sorbent bed train and thereby gain access to smaller changes in the concentration gradients and sharper separation. Hence, the generally held conviction that an increasing number of discrete sorbent beds in a sorbent bed train improves the separating efficiency for pseudo moving bed systems. However, multiple bed trains such as the tower trains require a relatively short bed depth of less than 1 meter for each of its vessels to manage an extremely high pressure drop associated with high flow velocities required by multiple bed trains and which are particularly observed in certain parts of such trains. This high pressure drop is as a rule isolated to those beds where high solids concentrations accumulate and where the sorbent medium expands due to the desorbent action. One option to reduce this restriction for large commercial plants is to increase the diameter of the column and reduce the bed depth for each sorbent bed in the sorbent bed train. It is, however, also generally recognized by experts that it becomes increasingly more difficult to maintain the required uniform cross-sectional distribution, uniform cross-sectional collection and uniform cross-sectional downward movement for fluids in pseudo-moving bed sorbent trains as the ratio of sorbent bed diameter to the sorbent particle size increases. Hence, separation performances deteriorate as a rule with increasing column diameter. Because of the recognized restrictions in sorbent bed diameter the need for multiple trains in large commercial installations is associated with greatly increased costs. All these aforementioned impediments are associated with reduced operating efficiency, greatly increased costs, increased control complexity and increased pressure drop restrictions. The various systems proposed and currently in use represent trial and error compromises deviating more or less from the ideal state for achieving the objectives referred to above.
I have now discovered the means to approach the ideal state of efficiency and performance at greatly reduced costs, reduced complexity of valving and reduced process control needs. Problems associated with the control of pressures are also virtually eliminated.
In view of the foregoing, it would be an advancement in the art to provide a novel, pseudo-moving bed apparatus in a single vessel having the capability to more efficiently utilize the sorption characteristics of the sorbent material in the sorbent bed. It would also be an advancement in the art to provide an apparatus and method for obtaining narrower fraction cuts through the more efficient utilization of the sorption characteristics of the sorption bed through a carefully controlled pseudo moving bed in the sorption bed. It would also be an advancement in the art to provide a sorbent bed with all of the zones for sorption and desorption of the desired constituent from the fluid stream contained in a single, continuous sorbent bed. Such a novel apparatus and method is disclosed and claimed herein.
BRIEF SUMMARY AND OBJECTS OF THE INVENTION
This invention relates to a novel apparatus and method for obtaining more efficient separation of constituents from a liquid stream through narrower fraction cuts from a simulated moving bed contained in a continuous, uninterrupted sorbent bed. A circulating liquid stream is continuously moved through the sorbent bed in an endless loop while carefully controlled amounts of feedstock and eluent are periodically introduced into the circulating liquid stream in coordination with the withdrawal of separated fractions from the circulating fluid as predetermined by the kinetics of the specific sorbent material. Multiple distributors and collectors provide for the ability to create a simulated moving bed within the single sorbent bed.
It is, therefore, the primary object of this invention to provide multiple distributors and collectors with uniform cross-sectional functionality imbedded in the sorbent material contained in a single, uninterrupted bed functionally operating as a simulated, moving bed to balance unavoidable expansion and contraction of sorbent material in the sorbent bed to prevent bed compaction.
Another object of this invention is to periodically inject feedstream and eluent in the shortest possible time into the continuously circulating loop fluid at strategic positions and in coordination with the withdrawal of separated fractions for maintaining hydraulic integrity within the loop to provide for narrower fraction cuts.
Another object of this invention is to maintain fixed positions for inlet and outlet streams of the loop. Another object of this invention is to alternate feed and eluent addition in coordination with respective withdrawal of separated fraction.
Another object of this invention is to add feedstream and eluent simultaneously to the circulating fluid of the simulated moving bed with uninterrupted, stationary sorbent bed, at fixed locations in coordination with the withdrawal of separated fractions from the circulating fluid.
Another object of this invention is to move addition and withdrawal positions along the length of the sorbent bed in coordination with the movement of the optimum concentration profile in the multiple zones within the circulating fluid flowing through the stationary sorbent bed.
These and other objects and features of the present invention will become more readily apparent from the following description in which preferred and other embodiments of the invention have been set forth in conjunction with the accompanying drawing and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic of a first preferred embodiment of the novel process of this invention;
FIG. 2 is a chart of the circulation liquid profile through the apparatus and method of this invention;
FIG. 3 is a schematic of a second preferred embodiment of the novel process of this invention; and
FIG. 4 is a schematic of a third preferred embodiment of the novel process of this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The invention is best understood by the following description with reference to the drawings wherein like parts are designated by like numerals throughout.
General Discussion
Through careful observation I have discovered that improved operating performance of pseudo-moving bed processes with increasing number of sorbent beds is largely a result of narrower fraction cuts and increased frequency for collecting and redistributing the circulating fluid through a continuous multiple bed sorbent train with discrete sorption beds. This approach inhibits, through frequent cross-sectional drainage and redistribution, the possibility of progressive channeling and lateral flow which otherwise would distort the moving front and the profile. Such flow deviations occur when moving sorbent bed fluid through a continuous sorbent bed with a large diameter and without special provisions for uniform perpendicular flow, distribution and drainage respectively.
This invention comprises an improved pseudo-moving bed system wherein a continuous sorbent bed configured from a single, uninterrupted sorbent bed without the need for multiple beds in the form of discrete compartments or separate vessels. The sorbent bed is characterized in that it contains all concentration gradients within the circulating fluid of a pseudo-moving bed train.
The single column eliminates the problem of pressure drop found in sorbent beds where the discrete zones are isolated in separate vessels or compartments within the vessel. This I have found to be important because of the nature of the sorption process as it effects the physical characteristics of the sorbent material. In particular, during the sorption process the individual beads of sorbent material shrink in size while those beads of sorbent material undergoing desorption tend to swell. This latter swelling phenomena causes significant compaction in a sorbent bed confined in a single vessel or compartment with a corresponding reduction of flow rate through the sorbent bed. However, the sorbent bed of my invention is contained in a single vessel with the discrete zones able to freely communicate throughout the entire length of the sorbent bed. This is important since it eliminates the foregoing problem of compaction that would otherwise occur if the various zones in the sorbent bed of my invention were confined in separate compartments.
The circulating fluid is continuously moving without interruption through the sorbent bed from the top to the bottom and returned to the top of the sorbent bed by means of a circulating pump to form an endless loop. Collectors are located at strategic positions in the sorbent bed to uniformly introduce feedstock and/or eluent over the entire cross-sectional are of the sorbent bed. Collectors are also located at strategic locations to uniformly withdraw fractions containing separated components from the circulating fluid over the cross-sectional area of the sorbent bed. The introduction of feedstock and eluent to the circulating fluid and the withdrawal of respective fractions from the circulating fluid occur periodically within the shortest possible time whenever the relevant concentration gradient within the circulation fluid arrives at the respective distributors/collectors. Uniform perpendicular and downward movement of circulating fluid is maintained throughout the entire sorbent bed at predetermined, changeable flow rates. Only a portion of the circulating fluid containing the desired concentration gradient is periodically withdrawn at the preselected location. An equivalent volume of feedstock and/or eluent is added to the circulating fluid at the preselected locations while the remaining part of the circulating fluid (plus added feedstock and eluent after becoming part of the circulating fluid) continues its downward travel through the sorbent bed. The circulating fluid passes from top to bottom through the sorbent bed and back to the top to form an endless loop. This circulating fluid maintains a steady state, continuously moving fluid stream but with an unchanging yet dynamically moving concentration profile generated through the progressive and continuous sorption and desorption of sorbents. Collectors and distributors in this sorbent bed system are designed to achieve uniform, cross-sectional distribution of feedstock and eluent and collection of the respective fractions without removal of separating medium from the sorbent bed. These distributors/collectors may be operated in a static, fixed position for a dedicated function. Alternatively, they may be operated dynamically wherein they alternately function in each respective position for distribution or collection. The interior of the sorbent bed columns contain means to enforce uniform cross-sectional and perpendicular downflow without lateral movement for the circulating fluid. This new concept can also be applied to multiple sorbent bed trains in connection with chromatography, ion exclusion, ion exchange or any separation process requiring sorbent beds.
In studying the operational limitations of the pseudo-moving bed process I have also discovered the fundamental means for projecting an accurate basic circulation flow and for predicting and maintaining a steady state progressive movement of the four basic zones in a pseudo-moving sorbent bed. I found this to be based on the true liquid voidage between the solid sorbent particles in the noncompressible sorbent bed and the application of the specific kinetics for the sorbent medium. These values can be experimentally determined for each specific sorbent medium and column design. For spherical, uniform particles with a mean diameter of about 320 microns I have determined the voidage to be about 48% of the total sorbent bed volume in columns designed according to this invention and used in ion exclusion operations. I have also determined experimentally the basic kinetics of the sorbent required for predicting the movements of the various zones through a pseudo-moving sorbent bed to assure depletion of the circulation fluid from the sorbed substance and regeneration of the sorbent with the eluent. These functions are defined within the scope of this invention as:
a. The ability to retain a fixed quantity of the sorbed component. For the conditions used in this demonstration this value was 31 grams sucrose/liter sorbent medium.
b. The average rate of sorption from the blended mixture For the conditions in the examples given below it was to be 1.5 grams/liter sorbent/minute with a range between 0.5 to about 3.5 grams sucrose/minute/liter sorbent medium.
c. The average rate of desorption from the sorbent medium loaded with sucrose. The desorption rate for the sorbent medium and conditions in this demonstration it was to be 3.05 grams sucrose per minute per liter sorbent medium with a range between over 7 grams to under 1 grams sucrose/minute/liter sorbent medium. Desorption is primarily driven by concentration differences.
With this information it is now possible to project correctly the amount of loading per time unit and the maximum velocity of the circulation fluid during the sorption and desorption process in the sorbent bed to move the optimum concentration profile at steady state and in the proper time frame in front of respective distributors and collectors while keeping respective frontal zones separated from each other.
Detailed Description
FIG. 1 illustrates the essential components required for a first preferred embodiment of the simulated moving bed according to this invention shown generally at 10 and includes a column 12, having an eluent dome 13, a sorbent bed 14, a circulation distributor 16, a secondary distributor 17, an effluent collector 18, and a circulation collector 19. Also included are a circulation pump 20, a feedstock valve 22, eluent valves 24 and 25, an extract valve 26, a raffinate valve 27, a circulation flowmeter 30, feedstock flowmeter 32, eluent flowmeter 34, effluent flowmeter 35, check valve 36 and pressure sensors 40-43.
Special means for preventing lateral flow within the sorbent bed and for enforcing uniform distribution and collection are not shown.
FIG. 1 provides for the operation of distributors 16 and 17 along with collectors 18 and 19 in a static mode, each with a dedicated, single function of injection with alternate withdrawal of separated fractions. Sorbent bed 14 is operated as a pseudo-moving bed system within column 12 which is configured as a single column containing sorbent bed 14 as a continuous sorbent bed. The top of sorbent bed 14 may be confined either by a flat, horizontal enclosure of the column (not shown) or by a hydraulic dome or eluent dome 13 formed from the incoming eluent, eluent 45, which in turn is confined by the dished head of the column enclosure of eluent dome 13 as shown in FIG. 1. In the preferred, less costly latter case eluent 45 is added to the top of eluent dome 13 whenever the scheduled addition for eluent 45 at that position occurs. Eluent 45 hydraulically and uniformly pushes the underlying interface into the circulating fluid throughout the cross section of column 12. The circulating fluid is also continuously and uniformly injected through distributor 16 across the cross section of sorbent bed 14. When operating with a flat horizontal top enclosure (not shown) for sorbent bed 14, the top eluent injection through valve 25 would be adjacent to injection of feedstock 44.
FIG. 2 illustrates an optimum concentration profile throughout the circulation fluid in sorbent bed 14 (FIG. 1). This concentration profile is generated and maintained when operating at steady state according to this invention. With the lowest solids concentration in the circulation fluid represented by Zone A in FIG. 1 (at circulation distributor 16) eluent 45 is added to eluent dome 13 during a brief period while Zone D, representing the leading front of the nonsorbed components, is moving across collector 18. During this brief period of eluent 45 addition to the top of sorbent bed 14 the most favorable raffinate 47 fraction located in Zone D and containing the nonsorbed component is withdrawn through collector 18 and valve 27. At the same time Zone B contains the desorbed fraction and a concentration gradient equivalent to the feedstock is represented by Zone C. Circulation pump 20 is manipulated to move the concentration profile as illustrated in FIG. 2 without interruption around this endless loop in harmony with the brief periods of additions to and withdrawals from the endless loop while sorption and desorption i continuously proceeding in various parts of sorbent bed 14. This manipulation of the circulation pump 20 moves in due time the most favorable concentration for the desorbed component in Zone B in front of collector 18 while the feed stock 44 concentration profile arrives with Zone C at the circulation distributor 16 and the lowest total dissolved solids concentration in Zone A surrounds the secondary distributor 17. At that point and for the shortest possible time feedstock 44 is added through valve 22 to the circulation fluid in Zone C while the desorbed component, extract 46, is withdrawn through collector 18 and valve 26. Simultaneous with the withdrawal of extract 46 through collector 18 and valve 26 eluent 45 may be added through valve 24 and secondary distributor 17 to Zone A at a preselected rate to maintain the predetermined overall ratio of eluent 45 to feedstock 44 for a complete cycle along with the desired ratio of the separated fractions to each other for a complete cycle. The operation of pump 20 is continuous but variable to move circulating fluid through circulation circuit 21 at a predetermined but changeable rate through the sorbent bed 14 and to maintain a progressive concentration profile at steady state for a total utilization of all sorbent medium in sorbent bed 14 in harmony with the kinetic properties of the sorbent material.
FIG. 3 demonstrates the manifolding according to this invention for a single sorbent bed featuring dedicated operation of distributors/collectors but with simultaneous injection of feedstock and eluent to the circulation fluid for the shortest possible time while at the same time withdrawing separated fractions from the circulation fluid through dedicated collectors. The circulation flow is maintained uninterrupted but at a somewhat reduced rate during the short injection period. In its most basic form the configuration in FIG. 3 according to this invention is shown generally at 50 and includes a vessel 52 with a sorbent bed 54. The upper end of vessel 52 is configured with an eluent dome 56. Also included are an upper circulation distributor 60, extract collector 61, feedstock distributor 62, raffinate collector 63, recirculation collector 64, recirculation pump 85, eluent valve 67, extract valve 75, feedstock valve 71, raffinate valve 81, eluent flowmeter 68, extract flowmeter 76, feedstock flowmeter 72, raffinate flowmeter 82, recirculation flowmeter 88, pressure sensors 90-93, and optional outlet valve 69, for backwashing purposes.
Recirculation circuit 84 is provided and includes pump 85, pressure gauges 91 and 92, and flowmeter 88 to monitor the flow therethrough. Recirculation liquid is withdrawn from vessel 52 through recirculation collector 64 and returned to vessel 52 through circulation distributor 60. FIG. 3 illustrates operation with an eluent dome 56 but may be configured with a flat horizontal column top (not shown) without freeboard over the sorbent bed in which case the eluent injection is projected to be in the recirculation circuit 84. The top of sorbent bed 54 may be confined either by a flat, horizontal top (not shown) on vessel 52 or by a hydraulic dome formed as eluent dome 56 which in turn is confined by the upwardly dished head of vessel 52 as shown in FIG. 3. In the preferred, less costly latter case eluent 66 is added to the top of eluent dome 56 whenever the scheduled addition for eluent 66 at that position occurs. Eluent 66 in eluent dome 5 hydraulically pushes the eluent dome interface uniformly throughout its cross-sectional area into the circulating liquid. Circulating liquid from recirculation circuit 84 is continuously injected uniformly into sorbent bed 54 across the cross-section defined by the upper distributor 60.
Referring now to FIG. 4, a third preferred embodiment of the concentration apparatus of this invention is shown generally at 100 and includes a vessel 102 having a sorbent bed 104 therein. A plurality of distributor/collectors are interposed across the cross-sectional area of sorbent bed 104 at preselected locations along the longitudinal axis of sorbent bed 104. An upper distributor 106 is placed on the upper surface of sorbent bed 104. Collectors 110, 112, 114 and 116 are uniformly spaced throughout the length of sorbent bed 104 with collector 116 located at the bottom of sorbent bed 104. Collectors 110, 112 and 114 simultaneously serve as distributors. However, for sake of clarity and to facilitate the discussion of their function, these distributors are shown separately and are described as distributors 111, 113 and 115, respectively. A recirculation circuit 120 includes a pump 122, pressure gauges 124 and 125 along with a flowmeter 126. Feedstock 130 enters the circulatory system of apparatus 100 through a flowmeter 129, and the flow thereto regulated by the selective operation of valves 131-134 in cooperation with valves 142 and 144 which also control portions of eluent 140. For example, feedstock 130 is directed to distributor 111 by opening valve 133 while valves 132, 134, 131 and 142 are closed. To direct feedstock 130 into distributor 113, valve 131 is opened while valves 133, 144, 132 and 134 are closed. Similarly, feedstock 130 is directed into distributor 115 by opening valve 132 with valves 131, 133, 134 and 143 closed. Feedstock 130 can also be diverted into the recirculation circuit 120 by opening valve 134 with valves 132, 131, 133 and 141 closed. Feedstock 130 is introduced into recirculation circuit 120 upstream of pump 122 in order to assure thorough mixing of the two streams as they pass through pump 122.
Eluent 140 passes through flowmeter 139 and is then directed to any one of eluent dome 103 or distributors 111, 113 or 115. Eluent 140 is directed into eluent dome 103 by opening valve 141 while keeping valves 142, 144 and 143 closed. Eluent 140 is directed into distributor 111 by opening valve 142 while keeping valves 141, 133, 144 and 143 closed. Correspondingly, eluent 140 is directed into distributor 113 by opening valve 144 with valves 141, 142, 143 and 131 closed. Eluent 140 is directed into distributor 115 by opening valve 143 and keeping valves 141, 142, 144 and 132 closed.
Extract 150 is removed through flowmeter 149 and can be obtained from any one of collectors 110, 112, 114 or 116. From collector 110, extract 150 is removed by opening valve 151 while closing valves 163, 152, 153 and 155. Removal of extract 150 from collector 112 is accomplished by opening valve 152 while closing valves 164, 151, 153 and 155. From collector 114, extract 150 is removed by opening valve 153 while closing valves 161, 151, 152 and 155. Extract 150 is removed from collector 116 by opening valve 155 while closing valves 162, 153, 152 and 151.
Raffinate 160 is removed through flowmeter 159 from any one of collectors 110, 112, 114 or 116. From collector 110, raffinate 160 is removed by opening valve 163 while closing valves 164, 151, 161 and 162. Raffinate 160 is withdrawn from collector 112 by opening valve 164 while closing valves 163, 152, 161 and 162. Raffinate 160 is removed from collector 114 by opening valve 161 while closing valves 153, 162, 163 and 164. Raffinate 160 is removed from collector 116 by opening valve 162 while closing valves 155, 161, 163 and 164.
FIG. 4 comprises the required components according to this invention when operating a single, continuous sorbent bed functioning with dynamic sequencing wherein injections of feedstock and eluent to the circulation fluid and withdrawals of separated fractions from the circulation fluid occur simultaneously within a short period of time from distributors/collectors which progressively change in their respective function. As the profile according to FIG. 2 in the circulation fluid moves continuously at steady state through the sorbent bed the respective injections of eluent and feedstock to the circulation fluid and the withdrawal of separated fractions from the circulation fluid occurs approximately simultaneous through assigned distributions/collectors for a brief period whenever the relevant concentration front travels across the relevant distributor/collector while the circulation fluid continuous downstream. Relevant inlet and outlet valves are opened approximately simultaneously at that time to allow injection of eluent and feedstock through preselected distributors together with the withdrawal of an equivalent portion of the circulation fluid from preselected collectors respectively while the remaining circulating flow continuous uninterrupted but at a somewhat reduced rate during the injection period.
The improvements are applicable to any form of pseudo moving bed separation. Any suitable sorbent material may be used but the preferred material is a uniform, spherical, gel type, noncompressible polystyrenic cation exchanger crosslinked with 6-8% divinylbenzene, a particle size of under 400 microns with a coefficient for particle size variation of less than 10. Variations in the kinetic nature and physical configuration of the sorbent medium will have a decisive impact on the basic circulation flow rate required to maintain a steady state profile. Any suitable sorbents may be used in combination with this invention by adjusting the basic circulation flow, loading and other operating parameters to the specific kinetics, particle size and particle size distribution of the sorbent medium used. When used in ion exclusion such as for the recovery of sucrose from low sugar purity liquors the sorbent medium should preferably be in its ionic potassium form. When used for the chromatographic separation of fructose from fructose/glucose blends the sorbent medium should preferably be in its ionic calcium form. With suitable sorbents the improvements according to this invention may be applied wherever it becomes necessary to separate mixtures into individual components or groups of components. The technique may also be extended to improve the efficiency in ion exchange operations as well.
The following examples ar given to detail the procedure according to this invention for the fractionation of sucrose from impure sugar solutions such as final molasses having sugar purities of about 60% on total dissolved solids or mother liquors from the second crystallization stage of sugar beet liquors with a sugar purity of about 75% on total dissolved solids. Total dissolved solids for the feed syrup is preferably as high as possible but is usually held for practical reasons in the range between 60-75%. Operating temperatures should be sufficiently high to minimize the negative impact of viscosity on pressure drop without significant thermal degradation on system components which suggests a range between 65-85 degrees Celsius. Operating capacities depend somewhat on the sugar purity of the feed syrup and may vary between less than 500 kg to over 700 kg total dissolved solids per cubic meter sorbent medium per day for ion exclusion work. Other conditions imposed on the operation include the ratio of eluent to feed syrup and the raffinate to extract ratio. The sorbent medium in the first example is a polystyrenic gel type cation exchanger in the potassium form, crosslinked with 6% divinylbenzene having a mean particle size of 320 microns with a coefficient of variation for particle size distribution of less than 10. Feed syrup in the first example is the mother liquor from a beet sugar crystallization with a sugar purity of 75% of total dissolved solids, a total dissolved solids content of 70% and a temperature of 80 degrees Celsius for both the feed syrup and the eluent. Feed syrup and eluent are both free of suspended solids which could foul the sorbent bed and contain less than 1% multivalent cations on total cations to prevent fouling of the functional groups. Substantial variations from these conditions may be practiced as long as the operating parameters are stable within narrow tolerances throughout each specific operation.
EXAMPLE 1
Pseudo-moving Bed Operation with a Single Sorbent Bed, Fixed Distributor Functions and Alternate Injection of Feed Syrup and Eluent and Withdrawal of Separated Fractions in a Short Period of Time (FIG. 1)
A vertical column, vessel 12, with an inside diameter of 50 centimeters and height of 490 centimeters was designed as diagrammatically illustrated in FIG. 1. Vessel 12 was uniformly packed with the sorbent medium described above to form sorbent bed 14. Condensate water which was free of dissolved or suspended gases was used as a slurrying agent to transfer the resin until sorbent bed 14 became a noncompressible, uniformly packed sorbent bed that extended from collector 19 to distributor 16. Under these conditions the space occupied by the free water between the sorbent particles represented about 48% of sorbent bed 14 which is the displacement volume in a complete cycle for the movement of the excluded ions and represents the product of circulation flow and total cycle time. The packed column of sorbent bed 14 was first brought to a steady state condition (as reflected by a concentration profile similar to that shown in FIG. 2) by following a series of consecutive steps 1 through 4, outlined below. That profile is than retained and moved continuously through the sorbent bed at steady state by continued cycling of steps 1 through 4.
Step 1: Injecting Eluent and Withdrawing Raffinate During Continued Circulation
Step 1 is arbitrarily defined with the nonsorbed components in Zone D with the most desirable raffinate concentration profile surrounding collector 18 while the condition in Zone A of circulation liquid nearly void of dissolved solids arrives at distributor 16. At this point eluent is introduced through control valve 25 at a flow rate of 17.8 liters per minute for 5 minutes to move eluent liquid uniformly over the entire cross-section of sorbent bed 14 through the interface at distributor 16 while raffinate is withdrawn simultaneously through collector 18 and control valve 27 at an equivalent rate to maintain steady state pressure at the suction of pump 20 as shown by pressure gauge 42. The circulation flow rate as measured at flowmeter 30 is maintained at about 4.4 liters per minute during step 1 by manipulating pump 20.
Step 2: Recycle
At the termination of step 1, control valves 25 and 27 close and a circulation flow of 18.0 liter/minute as measured by flowmeter 30 is maintained during step 2 for a period of about 10 minutes or until the desired extract concentration profile in Zone B surrounds collector 18. A minimum total dissolved solids concentration surrounds distributor 17 in Zone A and a purity equivalent to the feedstock surrounds distributor 16 in Zone C.
Step 3: Injecting Blend and Withdrawing Extract During Continued Circulation
Termination of step 2 and the beginning of step 3 is initiated when the optimum extract concentration in Zone B of the circulation liquid arrives at distributor 18, minimum total dissolved solids are measured in Zone A at distributor 17 and feedstock purity in Zone C surrounds distributor 16. At this point and for a period of 3 minutes feed stock 44 is injected into the circulation liquid at a rate of 5.3 liters per minute through control valve 22 and distributor 16, eluent is injected via control valve 24 and distributor 17 at a rate of 2.1 liters per minute and extract 26 is simultaneously withdrawn via collector 18 and control valve 26 at a rate of about 7.4 liters per minute as measured by flow meter 35. This rate is sufficient to maintain suction pressure for pump 20 at its predetermined level. The recycle flowrate through recirculation circuit 24 during step 3 is maintained at 15 liters per minute.
Step 4: Recycle
At the termination of step 3, control valves 24 and 22 close and the recycle flow rate is increased to 18 liters per minute as measured at flowmeter 30 for a period of 12 minutes or a condition which returns the imaginary zones in sorbent bed 14 to a liquid concentration profile to the same position at the end of step 4 as was evident at the beginning of step 1. The termination of step 4 ends a complete cycle and initiates the beginning of a new cycle with the start of step 1.
When starting with a condition where the sorbent medium in sorbent bed 14 is totally surrounded by water a steady state is reached in about 15 hours following a series of cycled steps 1 through 4. It is possible to arrive in under 6 hours at steady state conditions with certain other manual manipulations.
Results
At steady state operation the sugar purity of the collected extract 30 is about 95% and has a total solids content of about 38% The sugar purity for raffinate 32 is about 11% and has a total solids concentration of about 4%. About 96.5% of the sugar introduced is found in extract 30 which also contains about 15% of the impurities. About 85% of the impurities are found in raffinate 32 which also contains about 3.5% of the sugar introduced.
EXAMPLE 2
Pseudo-moving, Single Bed Separator With Stationary Positions of Inlet and Outlet Points, Simultaneous Introduction of Feedstock and Eluent and Withdrawal of Fractionated Eluents in the Shortest Possible Time. (FIG. 3)
FIG. 3 diagrammatically illustrates another version of a single pseudo moving sorbent bed separator according t this invention. This version is also based on the imaginary division of a single sorbent bed into four basic Zones A, B, C and D and a concentration profile similar to that shown in FIG. 2. The size of sorbent bed 54 and other operating conditions are the same as for Example 1.
Step 1: Injection of Blend and Eluent and Withdrawal of Fractionated Eluents During Continued Circulation
Step 1 is initiated with the circulation liquid exhibiting a concentration profile similar to that illustrated in FIG. 1 with the lowest total dissolved solids concentration in Zone A at distributor 60, optimum extract concentration in Zone B at collector 61, feedstock purity in Zone C at distributor 62 and optimum raffinate concentration in Zone D at collector 63. Valves 67, 75, 71 and 81 are opened about the same time to (1) inject eluent 66 into Zone A at a rate of 19.9 liters per minute for 3 minutes through top valve 67 and thereafter for an additional 2 minutes at a rate of 17.8 liters per minute, (2) withdraw extract 74 for 3 minutes from Zone B through collector 61 and valve 75 at a rate of 7.4 liters per minute, (3) inject feedstock 70 for 3 minutes into Zone C through valve 11 and distributor 62 at a rate of 5.3 liters per minute, and (4) withdraw raffinate 80 for 5 minutes at a rate of about 17.8 liters per minute from Zone D through collector 63 and valve 81 to maintain suction pressure for pump 85 at the predetermined level. Pump 85 is manipulated during the first three minutes of step 1 to maintain a circulation flowrate of 5.0 liters per minute as measured at flowmeter 88. Valves 75 and 71 close after 3 minutes into step 1, while valves 67 and 81 remain open for 5 minutes while the circulation flow increases to 7.5 liters per minute during the final 2 minutes of step 1.
Step 2: Recycle
Valves 67 and 81 are closed at the end of step 1 and circulation pump 85 is manipulated to maintain a circulation flowrate of 18.0 liters per minute across flowmeter 88 for a period 25 minutes or until the concentration profile which prevailed at the beginning of step 1 is re-established throughout the sorbent bed.
Results
Overall operating results will be similar to those shown for example 1.
EXAMPLE 3
Pseudo Moving, Single Bed Separator with Simultaneous Injections of Feed Syrup and Eluent and Withdrawals of Separated Fractions using Dynamically Shifting Functions for Respective Distributors and Collectors (FIG. 4)
Example 3 is based on the operation with the design according to this invention illustrated in FIG. 4 and using the basic operating conditions as for Example 1.
Step 1: Injecting Blend and Eluent While Withdrawing Separated Fractions During Continued Circulation
With the system at steady state and an optimum concentration profile similar to that illustrated in FIG. 2 established, the beginning of step 1 has been arbitrarily assigned when the circulation liquid surrounding the circulation distributor 106 in Zone A is nearly void of any dissolved substance. At that point the circulation liquid at collector 110 in Zone B is approximately at the highest sugar purity while approximately purity equivalency between the feed syrup in the feedstock 130 and the circulation liquid 120 is reached at distributor 112 in Zone C and the desired composition in raffinate 160 is measured at collector 114 in Zone D. At that point, top valve 141 is opened to inject water at a rate of 15.9 liters per minute, valve 151 at distributor 110 is opened to withdraw 3.8 liters per minute extract 150, valve 131 at distributor 112 is opened to inject 2.65 liters per minute feedstock 130 and valve 161 at distributor 114 is opened to withdraw approximately 14.75 liters per minute raffinate to maintain the hydraulic balance in the loop by controlling the suction pressure at pump 122 in the target range. Pump 122 is manipulated during step 1 to maintain the flow across circulation flowmeter 126 at 6 liters per minute. The duration of step 1 is 1.5 minutes.
Step 2: Recycle
All inlet and outlet valves are closed at the beginning of step 2 while pump 122 is manipulated to maintain for 6 minutes a circulation flowrate across flowmeter 126 of 18.5 liters per minute or until the optimum raffinate concentration in Zone D surrounds collector 116.
Step 3: Injecting Blend and Eluent While Withdrawing Separated Fractions During Continued Circulation
Step 3 repeats the flow and time conditions for step 1 with the opening of valve 142 to inject water through distributor 111 at a rate of 15.9 liters per minute, valve 152 is opened to withdraw extract 150 through collector 112 at a rate of 3.8 liters per minute, valve 132 is opened to inject feedstock 130 at a rate of 2.65 liter per minute through distributor 115 and valve 162 is opened to withdraw raffinate through collector 116 at a flowrate of about 14.75 liters per minute to maintain the suction pressure for pump 122 in the preselected range while maintaining a basic circulation flowrate of 6 liters per minute. Step 3 is maintained for 1.5 minutes.
Step 4: Recycle
With all inlet and outlet valves closed step 4 repeats the conditions for step 2 until the sorbent bed profile has moved one position downstream or more precisely until the optimum raffinate concentration in sorbent bed 104 circulation liquid in Zone D surrounds collector 110, the circulation liquid in Zone A is nearly free of dissolved solids and surrounds distributor 112, the highest sugar purity is found in the Zone B of the circulation liquid surrounding collector 114 and nearly equivalent feedstock sugar purity is found in Zone C at collector 116.
Step 5: Injecting Blend and Eluent While Withdrawing Separated Fractions During Continued Circulation
The circulation flowrate as measured at flowmeter 126 changes to 20.75 liters per minute during step 5. All other flowrates as well as the step time remain as for step 1 after the concentration profile has moved two positions downstream with Zone D now located at collector 110 and raffinate 160 withdrawn therefrom through valve 163, Zone A around distributor 113 with eluent 140 now entering through valve 144, Zone B surrounding collector 114 and extract 150 withdrawn through collector 114 and valve 153 with Zone C surrounding collector 116 and feedsyrup 130 injected through valve 134 while all other valves are closed.
Step 6: Recycle
Step 6 repeats the flow and time requirements for step 2 to move the sorbent bed profile now three positions downstream from the starting position of step 1 or until the optimum raffinate concentration in Zone D surrounds collector 112, Zone A surrounds distributor 115, Zone B surrounds collector 116 and Zone C with sugar purity in the circulation liquid nearly equivalent to the feedstock now located at distributor 111.
Step 7: Injecting Blend and Eluent While Withdrawing Separated Fractions During Continued Circulation
With the circulation profile shifted one position downstream during steps 5 and 6 to position the raffinate Zone D around collector 112, Zone A around distributor 115, Zone B to collector 116 and Zone C to distributor 110 the respective valves 164, 143, 155 and 133 open for 1.5 minutes to deliver the respective flowrates specified for step 1 while maintaining pump 122 suction pressure in the assigned target range. The circulation flowrate measured at flowmeter 126 is controlled at 18.1 liters per minute during step 7 only for the duration of this step which is 1.5 minutes.
Step 8: Recycle
Step 8 is a repeat of step 2 to return the sorbent bed circulation profile to the position it occupied at the beginning of step 1.
Results
At steady state the extract has a sugar purity of 97% and contains about 96.6% of the sugar introduced with the feed syrup while rejecting about 89.8% of the nonsugars to the raffinate.
The present invention may be embodied in other specific forms without departing from its spirit or essential characteristics. The described embodiments are to be considered in all respects only as illustrative and not restrictive. The scope of the invention is, therefore, indicated by the appended claims rather than by the foregoing description. All changes which come within the meaning and range of equivalency of the claims are to be embraced within their scope. | An apparatus and process for concentrating a selected component from a multi-component liquid using a sorbent bed having a preferential sorption rate for the selected component. The sorbent bed is enclosed in a single vessel and is operated in a simulated moving bed technique whereby the flow profile of the liquid is continually moved downwardly through the sorbent bed. Recirculation is continuous but variable and is accompanied by the injection of eluent and feedstock and the removal of extract and raffinate at preselected times, locations, and amounts as a function of the kinetics and voidage of the sorbent bed. Extract purity and operational efficiency of the sorbent bed are the result of this novel apparatus and process. | 50,485 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Application No. 61/531,286, filed Sep. 6, 2011, the disclosure of which is incorporated herein by reference.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
[0002] NOT APPLICABLE
REFERENCE TO SEQUENCE LISTING, A TABLE, OR A COMPUTER PROGRAM LISTING COMPACT DISC APPENDIX
[0003] NOT APPLICABLE
BACKGROUND
[0004] Commercial wireless networks have evolved through several generations today with the latest fourth generation (4G) cellular wireless network based on OFDMA and MIMO antenna technology being optimized for packet data transmission, which is expected to dominate the overall volume of wireless network traffic. In addition to the large increases in data traffic, voice can also be supported by carrying speech frames as Voice-over-IP. However, data traffic has become the main driver for increasing wireless capacity. With the explosive adoption of smart phones and similar devices there is an increasing need for more and more data capacity.
[0005] Data applications are asymmetric there being much more demand for downlink capacity than for uplink capacity. This is also consistent with the flexibility in transmission equipment that can be supported by a cellular wireless network where the downlink transmission power from the Base Station (BS) to the User Equipment (UE) is much higher than the uplink transmission power from the UE to the Base Station.
[0006] Existing wireless technologies (e.g., CDMA HRPD, WCDMA HSDPA, and OFDMA, i.e., LTE and WiMAX) all have limitations due to underlying transmission technology. While OFDMA may theoretically have much higher transmission capacity over the same frequency range, it can be further improved by juxtopositioning various “flavors” of Smart Antenna and MIMO technologies, but these technologies are still fundamentally limited by legacy wireless network architecture.
[0007] The amount of data traffic in the current 4G and 3G networks has grown exponentially especially given the mass adoption of smart phones and other mobile devices. Yet, the RF spectrum that can be used commercially is limited and in North America the utilization of available spectrum is already near 80%. There is therefore a clear need for additional capacity per MHz of spectrum.
[0008] The Active Electronic Scanned Array (AESA) technology provides a means to fundamentally update the wireless network architecture, in particular that at the cell level and it provides the potential to increase network capacity significantly.
SUMMARY
[0009] The present invention solves the problem of providing additional capacity by introducing a Base Station in a cellular wireless network that comprises one or more Active Electronic Scanned Arrays (AESA), each of which comprises a plurality of transmitter modules (TxM), for transmitting a RF signal to a UE, each TxM for use with at least one other corresponding TxM, each TxM being spaced apart a distance equal to a function of a Radio Frequency (RF) wavelength used by a UE and the Base Station. An AESA also comprises a plurality of receiver modules (RxMs), for receiving a RF signal from the UE, each RxM for use with at least one other corresponding RxM, each RxM being spaced apart a distance equal to a function of the RF wavelength used by the UE and the Base Station.
[0010] An AESA can comprise a plurality of transmitter-receiver modules (TRM), each of which includes a physically combined transmitter, for transmitting a RF signal to a UE, and a receiver, for receiving a RF signal from the UE. The TRMs are spaced apart a distance equal to a function of the RF wavelength used by the UE and the Base Station.
[0011] The UE transmits, by using its TxM/TRM, a logical control channel that contains messages of its RF channel feedback. The Base Station, on receiving and decoding such information from the UE can adjust phase alignment of a group of two or more TxMs/TRMs for subsequently transmitting RF signals to the UE. In the opposite direction, the Base Station may also transmit such a logical control channel including similar kind of control information to the UE and to allow the UE to adjust phase alignment of the modules of the UE AESA.
[0012] The RF channel between the Base Station and the UE consists of two types of logical channels, i.e., the aforementioned logical control channel and the user traffic channel. The specific wireless technology, e.g., WCDMA, CDMA, WiMax, and LTE, may be designed with one or more logical control channels, and a plurality of traffic channels.
[0013] A controller for the AESA, as part of the Base Station, comprises an interface to be connected with the plurality of TxMs and the plurality of RxMs. In the AESA with the TRMs, the controller is connected with the combined TRMs. In the transmission direction, the controller steers the phase alignment of the at least two TxMs (or TRMs), on one of the AESA arrays, for transmitting signals to the UE. The controller determines the direction and the compactness of the electromagnetic field carrying the RF signal through the desired phase alignment. The controller also selects the number of TxMs (or TRMs), when combined through phase alignment, to provide a more, or less, sharply focused signal, and a stronger, or a weaker, signal which leads to increased, or decreased, data transfer rate and increased, or decreased, transmission range to the UE.
[0014] In the receiving direction, the controller steers the phase alignment of at least two RxMs (or TRMs) for receiving from the UE. It determines the direction of the RF signal to receive and the number of RxMs (or TRMs) for the specific UE to achieve a more, or less, sharply focused received signal, or a higher, or lower, signal gain.
[0015] Through coordinating all the transmission to and receiving from all UEs, and the transmission and receiving TxMs (or TRMs) and RxMs (or TRMs), the controller maximizes the aggregate data transfer rate over the cell covered by the Base Station.
[0016] The controller can be designed to operate in one or more layers. A controller may be connected to a sub-controller wherein the sub-controller is coupled with the TxMs, and the RxMs, or the combined TRMs of an AESA array. The sub-controller directly steers the TxMs and the RxMs, or TRMs. Hence, the main controller itself controls them indirectly, but can perform a more coordinating function; this allows the overall architecture to be scalable when necessary.
[0017] In another aspect of the invention, a method is provided for increasing transmission and reception capacity, by utilizing an AESA array in a node in the wireless network, where the AESA is coupled to a controller for controlling independent TxMs of the AESA. The controller selects a subset of the modules dynamically based on their location, geometry, and distance to each other measured as a function of the said RF wavelength in response to the UE provided UE RF channel feedback, via a logical control channel, the RF channel feedback being used for adjusting the phase alignment of the modules and optimizing the aggregate power level to maximize the data transfer rate, where the phase alignment controls the direction of transmission of the compatible RF signals to the UE and the number of selected sets of modules controls the sharpness of the signal and the aggregate power targeted at the UE.
[0018] In a further aspect of the present invention a controller is introduced. The controller controls multiple subsets of TxMs of the AESA array, where each subset is a group of TxMs selected based on their location, geometry, and distance to each other measured as a function of the said RF wavelength in response to the UE provided RF channel feedback. Each subset of TxMs transmits with compliance to a specific wireless technology standard, including GSM, WCDMA, CDMA, WiMAX, LTE, and their evolved standards to the UE capable of receiving and transmitting in the compatible technology. The selection of these TxM subsets are dynamic and based on the current RF environment characterized by the RF parameters in the system including the location of the UE and the UE's channel matrix.
[0019] The single Base Station supports multiple wireless technology standards at the same time by selecting different TxM subsets and transmitting according to the said technology standard over each subset. The controller includes broadcasting and detecting means for the particular radio technology of the UE and scheduling logic operating in a processor with an associated memory that selects one of the plurality of physical or logical sub-controllers that corresponds with the radio technology of the UE. Each sub-controller comprises the logic means for selecting one or more TxMs in the shared pool of such modules of the AESA to transmit a part of or a full frequency band specific to the UE. The number, location, geometry, and distance, to each other of these modules, measured as a function of the said RF wavelength in response to the UE provided UE RF channel feedback, via a logical control channel, are controlled to optimize the desired direction of transmission to the UE and the aggregate power targeted at the UE to maximize the data transfer rate.
[0020] In further aspect of the invention, a method is provided for increasing transmission and reception capacity, by utilizing an AESA array in a node in the wireless network, where the AESA is coupled to a controller for controlling independent TRMs of the AESA. The controller selects a subset of the modules dynamically in response to the UE provided UE RF channel feedback, via a logical control channel, RF channel feedback being used for adjusting the phase alignment of the modules and optimize the aggregate power level to maximize the data transfer rate, where the phase alignment controls the direction of transmission of compatible RF signals to the UE and the number of selected set of modules controls the sharpness of the signal and the aggregate power targeted at the UE.
[0021] In a further aspect of the present invention a controller is introduced. The controller controls multiple subsets of TRMs of the AESA array, where each subset is a group of TRMs selected based on their location, geometry, and distance to each other measured as a function of the said RF wavelength in response to the UE provided RF channel feedback. Each subset of TRMs transmits according to a specific wireless technology standard, including GSM, WCDMA, CDMA, WiMAX, LTE, and their evolved standards to the UE capable of receiving and transmitting in the compatible technology. The selection of these TRM subsets are dynamic and based on the current RF environment characterized by the RF parameters in the system including the UE RF channel feedback. The single Base Station supports multiple wireless technology standards at the same time by selecting different TRM subsets and transmitting the said technology standard over each subset. The controller includes broadcasting and detecting means for the particular radio technology of the UE and scheduling logic operating in a processor with an associated memory that selects one of the plurality of physical or logical sub-controllers that corresponds with the radio technology of the UE. Each sub-controller comprises the logic means for selecting one or more transmission modules in the shared pool of such modules of the AESA to transmit a part of or a full frequency band specific to the UE. The number, location, geometry, and distance, to each other of these modules, measured as a function of the said RF wavelength in response to the UE provided UE RF channel feedback, via a logical control channel, are controlled to optimize the desired direction of transmission to the UE and the aggregate power targeted at the UE to maximize the data transfer rate.
[0022] In a further aspect of the present invention a system providing increased transmission capacity in a wireless network comprises a user equipment (UE) in communication with a Base Station capable of at least one of GSM, WCDMA, CDMA, WiMAX, LTE, and their evolved technology standards. The BS comprises an (AESA) array, for transmitting and receiving RF radio frequency signals to and from the UE in the compatible technology standards. The UE contains TxMs and RxMs and transmits at least one logical control channel to provide its RF channel feedback, for example, its location and geographical information to the BS and a channel matrix that includes information of its estimate of the condition of the RF channels in the direction from the BS to the UE.
[0023] In another aspect of the present invention a system providing increased transmission capacity in a wireless network comprises a user equipment (UE) in communication with a Base Station capable of at least one of GSM, WCDMA, CDMA, WiMAX, LTE, and their evolved technology standards. The BS comprises an (AESA) array, for transmitting and receiving RF radio frequency signals to and from the UE in the compatible technology standards. The UE contains TRMs and transmits at least one logical control channel to provide its RF channel feedback, for example, its location and geographical information to the BS and a channel matrix that includes information of its estimate of the condition of the RF channels in the direction from the BS to the UE.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0024] The novel features believed characteristic of the invention are set forth in the appended claims. The invention will best be understood by reference to the following detailed description of an illustrative embodiment when read in conjunction with the accompanying drawings, wherein:
[0025] FIG. 1 is a military AESA radar installation in an F-22 Raptor Fighter;
[0026] FIG. 2 , depicts a block diagram of an AESA radar antenna, wherein each “pin” is an AESA transmitter/receiver module;
[0027] FIG. 3 , illustrates a high level block diagram of each TxM being connected to a phase shift module (PSM) that provides a controllable phase shift of the RF signal;
[0028] FIG. 4 a depicts two-sine waves that when perfectly aligned in phase multiply the signal;
[0029] FIG. 4 b illustrates the effect when two sine waves are perfectly out-of phase signals;
[0030] FIG. 5 depicts the additive effect of multiple Transmitter modules transmitting in phase;
[0031] FIG. 6 illustrates channel update as transmitted from the UE at regular intervals;
[0032] FIG. 7 a depicts a high level block diagram of a network in accordance with the present invention;
[0033] FIG. 7 b illustrates a User Equipment;
[0034] FIG. 7 c depicts a high level block diagram of a Base Station;
[0035] FIG. 8 a depicts a high level block diagram of a Base Station incorporating an AESA antenna configuration in accordance with a preferred embodiment of the invention;
[0036] FIG. 8 b illustrates a high level block diagram of the Active Electronic Scanned Array (AESA) configuration in a Base Station in accordance with a preferred embodiment of the present invention;
[0037] FIG. 9 is a high level flow chart for a process of utilizing a AESA in accordance with a preferred embodiment of the present invention; and
[0038] FIG. 10 depicts the Base Station transmission power in at least four different directions, each having the same spatial signature in accordance with a preferred embodiment of the present invention.
DETAILED DESCRIPTION
[0039] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the present invention.
[0040] Reference throughout this specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the appearances of the phrases “in one embodiment” or “in an embodiment” or “according to one embodiment” (or other phrases having similar import) at various places throughout this specification are not necessarily all referring to the same embodiment. Furthermore, the particular features, structures, or characteristics may be combined in any suitable manner in one or more embodiments. Furthermore, depending on the context of discussion herein, a singular term may include its plural forms and a plural term may include its singular form. Similarly, a hyphenated term (e.g., “on-demand”) may be occasionally interchangeably used with its non-hyphenated version (e.g., “on demand”), a capitalized entry (e.g., “Software”) may be interchangeably used with its non-capitalized version (e.g., “software”), a plural term may be indicated with or without an apostrophe (e.g., PE's or PEs), and an italicized term (e.g., “N+1”) may be interchangeably used with its non-italicized version (e.g., “N+1”). Such occasional interchangeable uses shall not be considered inconsistent with each other.
[0041] It is noted at the outset that the terms “coupled,” “connected”, “connecting,” “electrically connected,” etc., are used interchangeably herein to generally refer to the condition of being electrically/electronically connected. Similarly, a first entity is considered to be in “communication” with a second entity (or entities) when the first entity electrically sends and/or receives (whether through wireline or wireless means) information signals (whether containing data information or non-data/control information) to the second entity regardless of the type (analog or digital) of those signals. It is further noted that various figures (including component diagrams) shown and discussed herein are for illustrative purpose only, and are not drawn to scale.
[0042] The functionality can be implemented by means of hardware comprising several distinct elements and by means of a suitably programmed processing apparatus. The processing apparatus can comprise a computer, a microprocessor, a state machine, a logic array or any other suitable processing apparatus. The processing apparatus can be a general-purpose processor which executes software to cause the general-purpose processor to perform the required tasks, or the processing apparatus can be dedicated to perform the required functions. Another aspect of the invention provides machine-readable instructions (software) which, when executed by a processor, perform any of the described methods. The machine-readable instructions may be stored on an electronic memory device, hard disk, optical disk or other machine-readable storage medium. The machine-readable instructions can be downloaded to a processing apparatus via a network connection.
[0043] Abbreviations
[0044] 3GPP 3rd Generation Project Partnership
[0045] 3GPP2 3rd Generation Project Partnership 2
[0046] AESA Active Electronic Scanned Array
[0047] BTS Base Transceiver Station
[0048] CDMA Code Division Multiple Access
[0049] CQI Channel Quality Indicator
[0050] CSI Channel State Indication
[0051] DL Downlink
[0052] DRC Data Rate Control
[0053] FDMA Frequency Division Multiple Access
[0054] GPS Global Positioning System
[0055] HRPD High Rate Packet Data
[0056] HSDPA High Speed Downlink Packet-Data Access
[0057] LTE Long Term Evolution (3GPP)
[0058] MIMO Multiple-In Multiple-Out
[0059] OFDMA Orthogonal Frequency Division Multiple Access
[0060] PN Pseudo-sequence Number
[0061] PSM Phase Shift Module
[0062] RF Radio Frequency
[0063] Rx Receive
[0064] RxM Receiver Module
[0065] SC-FDMA Single Carrier-Frequency Division Multiple Access
[0066] TDMA Time Division Multiple Access
[0067] TRM Transmitter/Receiver Module
[0068] Tx Transmit
[0069] TxM Transmitter Module
[0070] UE User Equipment
[0071] UL Uplink
[0072] UMTS University Mobile Telecommunications System
[0073] WIMAX Worldwide Interoperability for Microwave Access
[0074] WCDMA Wide-Band CDMA
[0075] Active Electronic Scanned Array (AESA), is a key wireless technology in modern radar and typically requires a massive amount of compute-power to control and manage AESA transmission and reception. It is expected by the time of 4G wireless networks and beyond, the required computing power and the related AESA cost issues will be resolved due to continued progress in electronics and semiconductor technologies. Adapting the AESA technology to a mobile or fixed wireless network can provide many times of capacity increase in the downlink and uplink. AESA technology, when applied to wireless transmission equipment can improve capacity by utilizing thousands of transmitter modules in the Base Station and can devote as many transmitter modules to each user as needed and as permitted within the coverage of a cell. The cost of such equipment is currently high but, it is already trending down and with mass commercialization, the equipment would become affordable.
[0076] AESA transmission and reception can be designed to be directional towards individual User Equipment (UE). By increasing the number of transmitter modules that work together, the network can support users further and further away from the cell center as long as the uplink transmit technology from the user permits. And equally, it can scale up the amount of data transmitted to the user (or a group of users), depending on the RF environment of each user, by steering more transmitter modules towards the user in one or more specific directions. The capacity that can be exploited is potentially large as the transmission power can be scaled with more transmission modules and time-sharing the transmission of data to many users in many directions.
[0077] FIG. 1 is a photograph of a military AESA radar installation in an F-22 Raptor Fighter. The application of AESA technology, to date, has not been used in the commercial wireless communications field. However, with progress made in solid state electronic components, AESA transmitters have become much smaller and, with mass commercialization, trending to becoming more affordable.
[0078] FIG. 2 , illustrates a block diagram of an AESA radar antenna, wherein each of the multitude of pins as shown in FIG. 1 are represented by the small circles, each of the circles representing an AESA transmitter/receiver module (TxM/RxM). Note the “pins” should fill the AESA transmitter panel or panels, though not all are depicted in the figure. In an advanced fighter plane such as the F35, part of the AESA array can be directed for point-to-point high capacity data link communications. Each TxM consumes very little power, a few hundred milli-watts up to a few watts.
[0079] FIG. 3 depicts each TxM connected to a phase shift module (PSM) that provides a controllable phase shift of the RF signal. (The PSM can be a separate device or contained within the TxM.) A subset of the TxMs can be targeted in a specific direction towards a User Equipment (UE) where the Tx signal from each TxM overlaps in space and interferes constructively to reinforce the signal in this specific direction; this is done by controlling the PSM phase shift of the transmitted signal from each TxM. In a simple case, a TxM may transmit a narrow-band simple sine-wave form signal. Constructive interference between signals from different modules, when phase controlled, reinforces the signal in the desired direction. The Tx modules are controlled as a subset to a user and in time, where a control channel with the AESA array or any traditional 3G/4G technology is used for timing alignment, network signaling, and resource scheduling.
[0080] The target of the transmitted signal is a mobile or fixed wireless device generically referred to as a User Equipment (UE). The AESA Tx modules (TxM) are part of the Base Station transceiver system (BS), which utilizes the TxMs to schedule and transmit data to the UE.
[0081] Each of the TxMs is controlled so as to be phase aligned such that signals from the subset of TxMs interfere constructively (signals are additive) in the direction of a User Equipment and within a computed distance of the UE from the Base Station cell center. The UE transmits its RF channel feedback in the UL, including Channel State Information (CSI), including that for the DL channel to the UE and that for the UL channel from the UE, the accepted data rate from the Base Station to the UE, the transmitted data rate from the UE to the Base Station, and the position information of the UE transmitted signal, including, location, elevation, and orientation so that the TxM can be steered to transmit accurately to the UE even when it is mobile.
[0082] For example, by delaying the phase shift of some TxM elements in relation to other modules in a particular group of Tx modules, the direction of the transmitted signal is steered by the angle of θ as shown in FIG. 3 . Note, there are no moving parts in the steering of the transmission direction of the desired signals as the modules are electronically steered rather than being steered mechanically, which reduces the need for maintenance.
[0083] Each cell or sector within the wireless network has one or more AESA panels coupled with one or more Base Stations (see FIG. 2 ). The more TxM and RxM modules in the array the higher the potential transmission capacity, being limited only by the electric power supply, the space to accommodate the AESA, and the range of the transmission frequency band.
[0084] As illustrated in FIG. 4 a , two-sine waves multiply when perfectly aligned in phase. The signal strength almost doubles, hence even though an individual TxM power may be low, the cascaded transmit power of a group of aligned TxMs becomes large and can target a UE from a significant distance (however the signal will still attenuate in free space exponentially). The opposite is true when two sine-waves are out of phase as in FIG. 4( b ), where perfectly out-of phase signals sum to zero.
[0085] The phase shift is done in such a manner as to delay some of the TxM signals within the same subgroup where the signal phase aligns in a specific direction, resulting in constructive interference. In other directions, the signals interfere destructively and hence the signal is degraded. Because each TxM module transmits a small amount of power, the direction of constructive interference cascades and produces a stronger signal. The direction of non-constructive interference transmits no more than a few hundred meters before signals dissipate through attenuation in free space.
[0086] FIG. 5 illustrates the additive effect of multiple TxM transmitting in phase, where the signal is strengthened (i.e., appearing brighter) in the direction of the phase alignment.
[0087] The number of TxM modules required can be determined from a desired signal strength, which determines a modulation and coding scheme (hence the achievable data rate) and the expected attenuation of the signal in the transmission environment given the distance to the target receiver and the RF channel. Note there are other factors that limit the number of TxMs being added, for example, the Uplink (UL) transmission from the UE and the desired cell sizes. The estimate of the number of modules required can be computed from channel feedback from the UE in the UL The more TxMs are allocated to a target, the stronger the multiplied signal strength is, hence the higher modulation and coding scheme, or the further away the receiver may be located.
[0088] The Tx direction can be determined from periodic channel feedback by the UE in the UL direction. As illustrated in FIG. 6 , channel feedback update is transmitted from the UE at regular intervals to ensure that the BS has up to date information to determine the direction of the transmission to the UE.
[0089] In the simplest form, the TxM transmits a narrow band sine-wave signal that time-multiplexes a reference pilot signal with a predetermined modulation and coding scheme and bit sequence and payload data to the target UE. For GSM, CDMA, WCDMA, OFDMA (e.g., LTE and WiMAX), the respective transmitted signal waveform apply to that specific technology.
[0090] Each TxM module is an independent transmitter in the sense that it can be controlled to transmit a specific frequency at a time, and the directionality of the DL transmission is such that there is a high level of frequency reuse within the same network cell. Each TxM is capable of transmitting at a wide range of frequencies so that a Pseudo-random Number (PN) sequence may be used to control the transmission to use frequency-hopping for diversity gain and interference robustness of the design.
[0091] In the UL, the direction of transmission and channel feedback are reversed. In particular, the channel feedback includes Channel State Information (CSI), including that for the UL channel to the Base Station and that for the DL channel from the Base Station, the accepted data rate from the UE to the Base Station, the transmitted data rate from the Base Station to the UE, and the position information of the Base Station transmitted signal, including, location, elevation, and orientation. However, the same principles apply. In the UL the UE is the transmitter and the Base Station is the receiver. The Base Station Rx modules are steered in phase to align to a direction of the transmitted signal from the UE. This has the benefit of optimizing the desired signal in specific signal paths and direction, and minimizing any interference from other directions. A subset of RxMs can be controlled according to specific separation, as a function of the frequency wavelength, for a particular UE to maximize receive diversity or to maximize data rate.
[0092] The DL and UL transmitted signal may employ any existing wireless technologies, including CDMA, CDMA EVDO, WCDMA, and OFDMA (e.g., LTE and WiMAX) as defined by 3GPP and 3GPP2. A specific channel in the UL (or DL) direction is employed for signaling the channel feedback, and it may also be used for scheduling of resources for the DL (or UL) direction using any of these existing wireless technologies. The Base Station (or the UE) transmission direction can be adjusted in response to the channel feedback from the UE (or the Base Station), typically within milliseconds, to ensure adaptation to RF conditions and to keep up with UE mobility.
[0093] FIG. 7 a depicts a high level block diagram of a network in accordance with the present invention. The network can include one or more instances of user equipment (UEs) and one or more Base Stations capable of communicating with these UEs, along with any additional elements suitable to support communication between UEs or between a UE and another communication device (such as a landline telephone). Although the illustrated UEs may represent communication devices that include any suitable combination of hardware and software, these UEs may, in particular embodiments represent devices such as the example UE illustrated in greater detail by FIG. 7 b . Similarly, although the illustrated Base Stations represent network nodes that include any suitable combination of hardware and software, these Base Stations may, in particular embodiments, represent devices such as the example Base Station illustrated in greater detail by FIG. 7 c.
[0094] FIG. 7 b illustrates an example UE which includes a microprocessor, a memory, a transceiver, and an antenna. In particular embodiments, some or all of the functionality described above as being provided by mobile communication devices or other forms of UE may be provided by the UE processor executing instructions stored on a computer-readable medium, such as the memory shown in FIG. 7 b . Alternative embodiments of the UE may include additional components beyond those shown in FIG. 8 that may be responsible for providing certain aspects of the UE's functionality, including any of the functionality described above and/or any functionality necessary to support the solution described above.
[0095] As depicted in FIG. 7 b , the example Base Station includes a microprocessor, a memory, a transceiver, and an antenna. In particular embodiments, some or all of the functionality described above as being provided by a mobile Base Station, a Base Station Controller, a Node B, an enhanced Node B, or any other type of mobile communications node executing instructions stored in the memory. Alternative embodiments of the Base Station may include additional components responsible for providing additional functionality, including any of the functionality identified above and/or any functionality necessary to support the solution described above.
[0096] FIG. 8 a depicts a high level block diagram of a Base Station incorporating an AESA antenna configuration in accordance with a preferred embodiment of the invention. Base Station 802 includes controller 804 , which manages sub-controller 806 which, in turn, controls the transmitter and receiver modules of AESA 808 . The sub-controller may control and operate the TxMs and RxMs individually, in pairs or in groups of modules. Not pictured are UEs and the rest of the network of which Base Station 802 is an integral part. Even though there is only one sub-controller 806 shown for ease of explanation, there can be multiple sub-controllers that are controlled by controller 804 . As will be shown in FIG. 8 b , sub-controllers representing various and different radio access technologies can be simultaneously controlled both for transmitting and receiving. The AESA Base Station may be considered a “universal” Base Station as virtually any radio access technology may be handled at the same time both receiving and transmitting. This feature of the invention could give rise to an independent, single Base Station operator entity that can serve multiple telecom operators at the same time.
[0097] FIG. 8 b illustrates a high level block diagram of the AESA antenna configuration in a Base Station in accordance with a preferred embodiment of the present invention. High capacity AESA 808 is managed by controller 804 , which includes a number of sub-controllers for controlling various wireless technologies, three of which are illustrated here. Because of room and clarity of explanation only three technologies are represented here and include GSM-sc (GSM subcontroller) 806 a, WCDMA-sc 806 b and LTE-sc 806 c. The number of sub-controllers is limited only by available space and power requirements of AESA 808 . Various TxM/RxM pairs can be taken over and controlled by the individual subcontrollers on an as needed and as available basis. In other words, if a pair of TxM/RxM (previously used by GSM-sc) is now idle and a need arises for LTE transmission and reception, LTE-sc 806 c may be utilized by controller 804 to connect, e.g., Tx group 812 to an LTE enabled wireless communications device.
[0098] AESA 808 consists of a large number of low-powered, independent transmitter modules (TxM) 810 and a similarly large number (but not necessarily the same number) of independent receiver modules (RxM). Sub-controllers can take over various groups of transmitters and/or receivers (e.g., 812 , 814 , 816 and 818 ) in response to a UE's requirement for signal power. Because each TxM and RxM is independently controlled and can be spatially separated flexibly, a subset or subsets of TxM (or RxM) can be steered through phase-shift electronically using phase shift module (not shown) for beam-forming, Tx/Rx diversity, or spatial multiplexing to each UE within the coverage area of AESA 808 . A controlling algorithm has the flexibility to choose from a large number of active Tx/Rx module pairs or groups as well as applying different transmission methods to these subsets of modules.
[0099] The TxM and RxM are active and are independently (in frequency, phase, and power) steered utilizing the aforementioned phase shift module. The pairs or groups of TxM and RxM are utilized on an as-needed basis in subsets to the overall set of modules to support multiple UEs, each UE possibly using a different radio access technology, that are accessing the network. Since the modules are strategically separated spatially, flexibility is afforded by the reach (i.e., power level when interfering constructively) and Tx/Rx direction (i.e., phase shift).
[0100] The TxM and RxM modules may be physically combined as a TRM, thus each module in FIG. 8 a and FIG. 8 b is capable of transmitting in the DL, and receiving in the UL. Similar to the TxM and RxM each TRM module can be individually steered by the controller, but the transmit and receive direction will be the same.
[0101] FIG. 9 is a high level flow chart for a process of utilizing a AESA in accordance with a preferred embodiment of the present invention. The steps in this process are for an AESA having separate TxM and RxM modules. In a process involving TRMs (combination of TxM and RxM), the steps are similar and will not be recited here. The process involving TxM and RxM modules begins at step 902 with the reception of a signal (including control channels, traffic channels, channel feedback, and pilot signal) from a User Equipment (UE) at a Base Station in which an AESA is incorporated. The process then moves to step 904 where a controller for the AESA determines the wireless technology of the UE signal. Typically the UE registers with the system as it enters the system, including one or more of wireless technologies that it supports.
[0102] Next, the process proceeds to step 906 with the controller directing the signal to a sub-controller that handles the wireless technology of the UE. The wireless technologies that are handled by the Base Station in which AESA is installed may include CDMA, GSM, WCDMA and LTE. The ability to handle the different technologies is found in selecting available transmitter modules that are spaced a distance apart as a function of the wavelength of the operating frequency of the UE. Any of the modules, receiver or transmitter, can be used to carry signals to and from almost any UE because of the ability to select the spacing of the transmitting and receiving modules.
[0103] The sub-controller allocates frequencies and time slots for the transmission to and reception from the UE. It also determines the direction of the transmission and reception using data received from the UE RF channel feedback. More TxM modules are used for higher signal strength, and for a more sharply focused signal, specifically spaced TxM modules and the individual phase shifts are used for the transmission direction. Similarly, more RxM modules for higher gain, and specifically spaced RxM modules and the phase shifts for the direction. After the TxMs are chosen, the process moves to step 910 , where phase alignment is applied to the group of TxMs for transmission and RxMs for receiving. In the next step, step 914 , as the UE changes direction and distance from the Base Station, the Base Station continues to monitor the UE, and the process restarts from 902 again, where the number of TxMs and RxMs, phase alignment of each module, overall power, and overall gain, in UL and DL, are constantly adjusted by the sub-controller so as to maintain or increase data transfer.
[0104] In step 916 , as the UE using GSM wireless technology leaves the cell covered by the Base Station, another UE using LTE may enter the same cell. As the Tx modules are now idle, the LTE controller can utilize the vacant Tx and Rx modules for the LTE controller. If the GSM UE is in the cell when the LTE UE is acquired by the AESA Base Station, the LTE sub-controller selects idle RxM and TxM modules to connect to the LTE UE. As multiple UEs enter the cell, depending on the availability of Tx and Rx modules, all of the UEs regardless of wireless technology, can be served by the AESA Base Station.
[0105] FIG. 10 shows that the Tx power to the UEs in the same spatial signature group can be precisely controlled to multiplex many UEs in the same direction, which allows data rate maximization overall in the coverage area of the cell, and the power of different frequencies being limits to achieve a balanced data rate to the target UEs, while at the same time to reduce the interference to adjacent cells. Using LTE as an example, which uses OFDMA signals and have some very attractive properties, each TxM (or RxM) module group can be modulated with OFDM symbols to multiplex more users with the same spatial signatures as captured by channel feedback. The multiplexed OFDM signals may compose of many frequencies, have the same direction, and may have different power for each subset of frequencies.
[0106] In each direction, a specific AESA channel can be formed with reduced interference between channels. The lope of the channel can be controlled to be narrower or wider depending on the covered area and UEs as needed by controlling more or fewer TxM and RxM modules and their spacing on the AESA arrays. The important aspect of this Base Station architecture using the AESA is that each channel can be dynamically constructed depending on the need as obtained from the channel feedback from the UE. In fact, the different channels are omni-directional and spans different directions across 360 degrees and from the ground to the required elevation at different times and for different UEs.
[0107] Each channel can be transmitting one of the supported wireless technologies, i.e., GSM, CDMA, WCDMA, LTE, WiMAX, and their derivatives.
[0108] Although the described solutions may be implemented in any appropriate type of telecommunication system supporting any suitable communication standards and using any suitable components, particular embodiments of the described solutions may be implemented in a network, such as that illustrated in FIG. 7 .
[0109] As will be recognized by those skilled in the art, the innovative concepts described in the present application can be modified and varied over a wide range of applications. Accordingly, the scope of patented subject matter should not be limited to any of the specific exemplary teachings discussed above, but is instead defined by the following claims | A base station in a network includes an Active Electronic Scanned Array (AESA) to enhance and increase transmission and reception in a wireless telecommunications network. The AESA comprises a plurality of transmitter and receiver modules for sending and receiving signals from a User Equipment (UE) with increased signal strength and higher gain. The AESA comprises a central controller; and subcontrollers that cause signals to be directed to specific transmission modules (TxMs) and receiver modules (RxMs) in the AESA to send to the UE. By increasing the number of TxMs used, the signal strength to the UE can be increased significantly. Subcontrollers for handling different radio frequencies can be utilized in the same AESA so that multiple telecommunication systems can be accommodated on a single base station. | 44,122 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 11/408,474 filed on Apr. 21, 2006, which is incorporated by reference herein in its entirety.
FIELD
The present invention relates to covered stents for use in various medical procedures.
BACKGROUND
The following terms used herein are defined as follows:
The term “stent” means a frame structure containing openings through its wall, typically cylindrical in shape, intended for implantation into the body. A stent may be self-expanding and/or expanded using applied forces.
As used herein, the terms “covered stent” and “stent-graft” are used interchangeably to mean a stent with a cover on at least a portion of its length. The cover can be on the outer surface, the inner surface, on both surfaces of the stent, or the stent may be embedded within the cover itself. The cover may be porous or non-porous and permeable or non-permeable. Active or inactive agents or fillers can be attached to or incorporated into the cover.
Referring to FIG. 4 a , as used in this application, the term “wrinkle” 65 a , 65 b means a fold in a stent cover 62 that has a larger peak to valley height 64 than a thickness 66 of an adjacent stent strut 68 . In the illustrated instance where the cover is mounted within the stent, a wrinkle 65 a in a cover 62 on the outer surface of a covered stent 60 may be identified where the cover extends beyond the inner surface of the stent struts 68 . A wrinkle 65 b can also extend radially inward.
Referring to FIG. 4 b , a wrinkle 65 a in a cover on the inner surface of a covered stent 60 can extend radially outward. Such an outward-extending wrinkle may be identified where the cover 62 extends beyond the outer surface of the stent struts 68 as shown in FIG. 4 b . A wrinkle 65 b can also extend radially inward as shown in FIG. 4 b
Wrinkles can be observed with unaided vision or they can be observed and measured under magnification, such as optical microscopy. “Wrinkle-free” means a stent covering that is substantially free of “wrinkles.”
As used herein, the term “expand” has two distinct meanings. When used in the context of describing stents, it refers to the increase in diameter of those devices. When used in the context of ePTFE material, it refers to the stretching (i.e., expansion) process used to render PTFE material stronger and porous.
As used herein, the term “self-expanding” means the attribute of a device that describes that it expands outwardly, such as in a general radial direction, upon removal of a constraining means, thereby increasing in diameter without the aid of an external force. That is, self-expanding devices inherently increase in diameter once a constraining mechanism is removed. Constraining means include, but are not limited to, tubes from which the stent or covered stent device is removed, such as by pushing. Alternatively, a constraining tube or sheath may be disrupted to free the device or the constraining means can be unraveled should it be constructed of a fiber or fibers. External forces, as provided by balloon catheters for example, may be used prior to expansion to help initiate an expansion process, during expansion to facilitate expansion, and/or after stent or covered stent deployment to further expand or otherwise help fully deploy and seat the device.
As used herein, the term “fully deployed” refers to the state of a self-expanding stent after which the constraining means has been removed and the stent, at about 37° C. over the course of 30 seconds, has expanded under its own means without any restriction. A portion or portions of a self-expanding stent may be fully deployed and the remainder of the stent may be not fully deployed.
The phrase, “operating diametric range” refers to the diametric size range over which the stent or stent-graft will be used and typically refers to the inner diameter of the device. Devices are frequently implanted in vessel diameters smaller than that corresponding to the device fully deployed state. This operating range may be the labeled size(s) that appear in the product literature or on the product package or it can encompass a wider range, depending on the use of the device.
As used herein, the term “porous” describes a material that contains small or microscopic openings, or pores. Without limitation, “porous” is inclusive of materials that possess pores that are observable under microscopic examination. “Non-porous” refers to materials that are substantially free of pores. The term “permeable” describes a material through which fluids (liquid and/or gas) can pass. “Impermeable” describes materials that block the passage of fluids. It should be appreciated that a material may be non-porous yet still be permeable to certain substances.
Stents and covered stents have a long history in the treatment of trauma-related injuries and disease, especially in the treatment of vascular disease. Stents can provide a dimensionally stable conduit for blood flow. Stents prevent vessel recoil subsequent to balloon dilatation thereby maintaining maximal blood flow. Covered stents can provide the additional benefits of preventing blood leakage through the wall of the device and inhibiting, if not preventing, tissue growth through the stent into the lumen of the device. Such growth through the interstices of the stent may obviate the intended benefits of the stenting procedure.
In the treatment of carotid arteries and the neurovasculature, coverings trap plaque particles and other potential emboli against the vessel wall thereby preventing them from entering the blood stream and possibly causing a stroke. Coverings on stents are also highly desirable for the treatment of aneurismal vascular disease. The covers may further act as useful substrates for adding fillers or other bioactive agents (such as anticoagulant drugs, antibiotics, growth inhibiting agents, and the like) to enhance device performance.
The stent covers may extend along a portion or portions or along the entire length of the stent. Generally, stent covers should be biocompatible and robust. They can be subjected to cyclic stresses about a non-zero mean pressure. Consequently, it is desirable for them to be fatigue and creep resistant in order to resist the long-term effects of blood pressure. It is also desirable that stent covers be wear-resistant and abrasion-resistant. These attributes are balanced with a desire to provide as thin a cover as possible in order to achieve as small a delivery profile as possible. Covers compromise the flow cross-section of the devices, thereby narrowing the blood flow area of the device, which increases the resistance to flow. While increased flow area is desirable, durability can be critical to the long-term performance of covered stents. Design choice, therefore, may favor the stronger, hence thicker, covering. Thick covers, however, are more resistant to distension than otherwise identical thinner covers.
Some balloon-expandable stent covers are wrinkle-free over the operating range of the stents because the extreme pressures of the balloons can distend the thick, strong covers that are placed onto the stent at a less than a fully deployed stent diameter. Even the thinnest covers in the prior art such as those made of ePTFE (e.g., those taught in U.S. Pat. No. 6,923,827 to Campbell et al., and U.S. Pat. No. 5,800,522 to Campbell et al.), however, may be too unyielding to be distended by the radial forces exerted by even the most robust self-expanding stents.
Non-elastic and non-deformable self-expanding stent covers are, therefore, generally attached in a wrinkle-free state to the stent when the stent is fully deployed. When such covered stents are at any outer diameter smaller than the fully deployed outer diameter, the cover is necessarily wrinkled. These wrinkles, unfortunately, can serve as sites for flow disruption, clot initiation, infection, and other problems. The presence of wrinkles may be especially deleterious at the inlet to covered stents. The gap between the wrinkled leading edge of the cover and the host vessel wall can be a site for thrombus accumulation and proliferation. The adverse consequences of wrinkles are particularly significant in small diameter vessels which are prone to fail due to thrombosis, and even more significant in the small vessels that provide blood to the brain.
The use of thin, strong materials is known for implantable devices (e.g., those taught in U.S. Pat. No. 5,735,892 to Myers et al.). Extremely thin films of expanded PTFE (ePTFE) have been taught to cover both self-expanding and balloon expandable stents. Typically these films are oriented during the construction of the devices to impart strength in the circumferential direction of the device. Consequently, the expanding forces of the self-expanding stents may be far too low to distend these materials. In fact, such devices are generally designed to withstand high pressures. These coverings, like those of other coverings in the art, are wrinkle-free only when the devices are fully deployed.
Thin, extruded but not expanded fluoropolymer tubes have been used to cover self-expanding and balloon-expandable stents (e.g., U.S. Patent Application 2003/0082324 A1 to Sogard). These seamless extruded tube covers are applied to self-expanding stents in the fully deployed state of the stents. The stent coverings, therefore, possess wrinkles upon crushing the device to a diameter smaller than the fully deployed diameter.
Expanded PTFE material has been used to cover stents that are self-expanding up to a given diameter, then use the assistance of a balloon catheter or other expansion force to achieve the desired clinical implantation diameter (e.g., U.S. Pat. No. 6,336,937 to Vonesh et al). Such covers are wrinkled in the range of diameters up to the diameter at which the stent expands on its own. Beyond that diameter, the covers may be relatively wrinkle-free, however, the stent may no longer be freely self-expanding.
Another type of covered stent previously disclosed (e.g., U.S. Patent Application 2002/0178570 A1 to Sogard) is constructed with two polymeric liners laminated together yet not adhered to the stent. In the absence of bonding a liner to the stent, both an inner and outer liner are necessary and they need to be bonded together at the stent openings in order to construct a coherent stent-graft. This construction provides a relatively smooth liner on one side of the stent. The outer liner follows the geometry of the stent strut and is bonded to the inner liner. As such, according to the definition of a “wrinkle” as provided herein, the outer liner is wrinkled. Expanded PTFE liners of self-expanding covered stents made with shape memory alloys were taught to be laminated together at elevated temperatures, as high as 250° C. (and below 327° C.), while not exceeding a stent temperature which might reset the shape memory state of the alloy. In the absence of bonding the liners to the stent struts, gaps are formed between the liners. Such gaps may become filled with biological materials that compromise the blood flow area and, therefore, may restrict blood flow.
Without the addition of other materials, expanded PTFE materials must be heated well above 200° C. in order the heat bond them together. Given that these stent-graft devices are intended to self-expand at body temperature, the temperature at which the alloy may reset is necessarily close to body temperature. This thermal requirement obviates the possibility of heat bonding the liner to the stent at around a 250° C. temperature. Furthermore, the size of the covered stent that can be constructed in this manner is limited by the physics of heat conduction. That is, a 250° C. heat source must be at a suitable distance from the stent during the lamination process. The liners are laminated with the stent at a diameter less than deployed diameter, hence the size of the openings of the stent are smaller than if the liners were laminated at a larger stent diameter. Consequently, small diameter covered stents cannot be made in accordance with these teachings, nor can the liners be bonded to the stent.
U.S. Pat. No. 6,156,064 to Chouinard teaches use of dip coating to apply polymers to self-expanding stents. Stents and stent-grafts are dipped into polymer-solvent solutions to form a film on the stent followed by spray coating and applying a polymeric film to the tube. Stent-grafts comprising at least three layers (i.e., stent, graft, and membrane) are taught to be constructed in this manner.
Stents have also been covered with a continuous layer of elastic material. As taught in U.S. Pat. No. 5,534,287 to Lukic, a covering may be applied to a stent by radially contracting the stent, then placing it inside a tube with a coating on its inner surface. The stent is allowed to expand, thereby bringing it in contact with the coating on the tube. The surface of contact between the stent and the tube is then vulcanized or similarly bonded. No teaching is provided concerning the diameter of the tube relative to the fully deployed stent diameter. The patent specifically teaches in one embodiment the application of the coating on a stent in the expanded condition. The inventor does not teach how to eliminate or even reduce wrinkles in the stent cover. In fact, the patent teaches how to increase the thickness of the coating, a process that would only increase the occurrence of wrinkling. The patent teaches away from the use of a non-elastic material to cover the stent, and specifically teaches away from the use of a “Teflon®” (i.e., PTFE) tube.
U.S. Patent Application 2004/0024448 A1 to Chang et al teaches covered stents with elastomeric materials including PAVE-TFE. Self-expanding stent-grafts made with this material, like those made of other materials in the art, are not wrinkle-free over the operating range of the devices. These coverings of self-expanding stents are typically applied to the stent in the fully-deployed state. Consequently, wrinkles are formed when the stent-graft is crushed to any significant degree.
SUMMARY
The present invention is an improved expandable implantable stent-graft device that provides a smooth flow surface over a range of operative expanded diameters. This is accomplished by applying a unique cover material to the stent through a unique technique that allows the cover to become wrinkle-free prior to reaching fully deployed diameter. The unique cover material then allows the device to continue to expand to a fully deployed diameter while maintaining a smooth and coherent flow surface throughout this additional expansion.
In one embodiment the present invention comprises a diametrically self-expanding stent-graft device having a graft covering attached to at least a portion of the stent. The device is adapted to be constrained into a compacted diameter for insertion into a body conduit, which will produce wrinkles along its graft surface. However, when the device is unconstrained from the compacted diameter it will self-expand up to a fully deployed diameter with the graft being substantially wrinkle-free over diameters ranging from 50% to 100% of the fully deployed diameter.
Further improvements in the present invention may include providing a fluoropolymer graft component, such as an ePTFE, in the form of either a coherent continuous tube or a film tube. The graft and stent may be combined together through a variety of means, including using heat bonding or adhesive, such as FEP or PMVE-TFE.
By modifying the materials and/or the construction techniques, the range of wrinkle-free expansions can be increased to about 30%-100% or even wider ranges.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 a is a three-quarter isometric view of one embodiment of a covered stent of the present invention in the constrained state, having the cover mounted on the outside of the stent;
FIG. 1 b is a three-quarter isometric view of the embodiment of a covered stent of the present invention of FIG. 1 a in the fully deployed state;
FIG. 2 a is a transverse cross-section view of the embodiment of a covered stent of the present invention deployed to 30% of the fully deployed outer diameter of the device;
FIG. 2 b is a transverse cross-section view of the embodiment of a covered stent of the present invention deployed to 50% of the fully deployed outer diameter of the device with the smooth gradual transition of the adhesive-stent cover interface shown in detail in an enlarged sectional view;
FIG. 2 c is a transverse cross-section view of the embodiment of a covered stent of the present invention taken along line 2 c - 2 c of FIG. 1 b , deployed to 100% of the fully deployed outer diameter of the device with the smooth gradual transition of the adhesive-stent cover interface shown in detail in an enlarged sectional view;
FIG. 3 a is a photomicrograph showing the inside of a covered stent of the present invention that is constrained in a partially deployed state of about 50% of the fully deployed outer diameter of the device;
FIG. 3 b is a photomicrograph showing the inside of a covered stent of the present invention that is constrained in a partially deployed state of about 60% of the fully deployed outer diameter of the device;
FIG. 3 c is a photomicrograph showing the inside of a covered stent of the present invention that is constrained in a partially deployed state of about 70% of the fully deployed outer diameter of the device;
FIG. 3 d is a photomicrograph showing the inside of a covered stent of the present invention that is constrained in a partially deployed state of about 80% of the fully deployed outer diameter of the device;
FIG. 3 e is a photomicrograph showing the inside of a covered stent of the present invention that is constrained in a partially deployed state of about 90% of the fully deployed outer diameter of the device;
FIG. 3 f is a photomicrograph showing the inside of a covered stent of the present invention that is fully deployed;
FIG. 3 g is a photomicrograph showing the inside of a covered stent of the prior art that is constrained in a partially deployed state of about 50% of the fully deployed diameter;
FIG. 4 a is a transverse cross-section view of exemplary wrinkles in a cover on the outer surface of the stent; and
FIG. 4 b is a transverse cross-section view of exemplary wrinkles in a cover on the inner surface of the stent.
DETAILED DESCRIPTION
The present invention addresses the problem of wrinkles in the covers in stent-grafts. The covers of self-expanding stent-grafts heretofore exhibited wrinkles when deployed to diameters smaller than the diameter at which the cover was applied to the stent, which is typically the fully deployed diameter. Inasmuch as body conduits are rarely the exact diameter of the stent-graft, rarely uniformly circular in cross-section, and rarely non-tapered, sections or entire lengths of self-expanding stent-grafts frequently are not fully deployed and hence present wrinkled surfaces to flowing blood or other body fluids. Furthermore, covered stents are often intentionally implanted at less than their fully deployed diameters in order to utilize their inherent radial expansion force to better anchor the devices against the host tissue, thereby preventing device migration in response to blood flow. Such practices come at the expense of having to tolerate devices with at least partially wrinkled covers. The present invention involves the use of a unique stent cover material, one that combines two seemingly mutually exclusive properties—being both strong enough to withstand the forces exerted by constant, cyclic blood pressure and also distensible enough to expand in response to the expansion forces exerted by a self-expanding stent.
In addition, a unique manufacturing method had to be devised in order to utilize this material to construct a self-expanding stent-graft. The temperature-constrained shape-memory properties of self-expanding stents introduce significant processing challenges. Ultimately, a process was developed which entailed not only applying the cover to the stent in a cold environment, but also entailed bonding the cover to the stent at these cold temperatures.
Referring to FIGS. 1 a and 1 b , the present invention is directed to implantable device 60 having a self-expanding stent component 63 with either an inner or outer cover 62 (or both), that is wrinkle-free over an operating diametric range of the device. The cover 62 has wrinkles 65 in the constrained state as shown in FIG. 1 a . The wrinkles disappear once the device self-expands to the diameter at which the cover was applied to the stent. The cover 62 remains wrinkle-free as the device 60 self-expands even further as shown in FIG. 1 b . The invention addresses the clinical problems associated with wrinkles in self-expanding stent covers while providing the minimum amount of covering material. Wrinkles are known to disrupt blood flow and become sites for clot deposition which can ultimately lead to graft thrombosis and embolus shedding. These sequelae may create serious clinical consequences, especially in organs such as the brain. The incorporation of a single, very thin cover enables a stent-graft device with a profile dictated primarily by the stent strut dimensions, not by the mass or volume of the cover. The present invention, therefore, provides a heretofore unavailable combination of deployment diameter for a given size stent-graft and a wrinkle-free cover surface over a wide range of deployed diameters.
For use in the present invention, nitinol (nickel-titanium shape memory alloy) and stainless steel are preferred stent materials. Nitinol is preferred for its shape memory properties. The memory characteristics can be tailored for the requirements of the stenting application during the fabrication of the alloy. Furthermore, nitinol used to make the stent can be in the form of wire that can be braided or welded, for example, or it can be tubing stock from which a stent is cut. While nitinol offers a wide variety of stent design options, it should be appreciated that stainless steel and other materials may also be formed into many different shapes and constructs.
Stent covers of the present invention are preferably durable and biocompatible. They may be seamless or contain one or more seams. The stent covering of the present invention has a low Young's modulus, which enables it to be distended with the minimal force that is exerted by a self-expanding stent. Furthermore, the covering is provided with a minimal (or non-existent) elastic recoil force so that after stent expansion the covering does not cause the stent-graft to decrease in diameter over time. The cover is also preferably thin. Thinness has the multiple benefits of reducing the introduction size of the device, maximizing the blood flow cross-section, providing less resistance to radial expansion, and introducing less elastic recoil.
In a preferred embodiment, a nitinol stent is chilled and crushed to a diameter less than the fully deployed outer diameter. The chilling is desirable to help maintain the stent in the crushed state. The covering is then applied without creating wrinkles. The constrained diameter is selected according to the intended operating parameters of the device, such as about 90% of the fully deployed outer diameter or less, about 80% of the fully deployed outer diameter or less, about 70% of the fully deployed outer diameter or less, about 60% of the fully deployed outer diameter or less, and for most applications most preferably about 50% of the fully deployed outer diameter or less. While maintaining the device in the chilled state, the stent-graft is allowed to dry and then further crimped with a chilled crimping tool and transferred into a delivery catheter.
The stent cover may consist of fluorinated ethylene propylene (FEP) coating the nodes and fibrils of ePTFE film. Most preferably, a cover of ePTFE, is used to practice the invention. Whereas ePTFE is known for its high tensile strength, that strength is imparted only in the direction of expansion. If the ePTFE material is not expanded in the orthogonal direction (i.e., the transverse direction in the case of films) during the processing of the material, the ePTFE material is extremely distensible in that direction. Such materials have both very low tensile strength and very low Young's modulus in the transverse direction. The low Young's modulus property enables the material to distend under low forces. Films used to construct articles of the present invention can be easily elongated in the transverse direction by hand, thereby demonstrating their low Young's modulus values. In the most preferred embodiments, therefore, the ePTFE materials are in the form of very thin, highly porous films that are highly distensible in the transverse direction. The combination of high porosity and thinness result in a cover material that occupies minimal volume of the device. Expanded PTFE stent covers may offer additional advantages by virtue of the ability to provide and control their porosity. Various agents or fillers can be added to the surface or within the pores of the material. Such agents and fillers may include but are not limited to therapeutic drugs, antithrombotic agents, and radio opaque markers. If desired, portions of or the entire ePTFE cover may optionally be rendered non-porous or non-permeable by densifying, filling the pores, or through any other suitable means. Preferably, to provide added stability to the material, the ePTFE material is raised above its crystalline melt point, that is, the ePTFE material is “sintered.”
It is believed that thin ePTFE films possessing a thickness of less than about 0.25 mm are preferred for practicing the present invention. It is believed that even more preferred are films possessing a thickness less than about 0.1 mm. Preferred thin ePTFE films possess densities in the range of about 0.2 to about 0.6 g/cc. It is believed that more preferred thin ePTFE films have densities in the range of about 0.3 to about 0.5 g/cc. It is believed that preferred thin ePTFE films possess matrix tensile strengths in the range of about 70 to about 550 MPa and about 15 to about 50 MPa, in the longitudinal and transverse directions, respectively. It is believed that more preferred thin ePTFE films possess matrix tensile strengths in the range of about 150 to about 400 MPa and about 20 to about 40 MPa, in the longitudinal and transverse directions, respectively. The preferred film for use in practicing the present invention is a thin ePTFE film possessing a thickness of about 0.02 mm, a density of about 0.4 g/cc, longitudinal matrix strength of about 260 MPA, and a transverse matrix tensile strength of about 30 MPa.
It is believed that preferred thin ePTFE films possess Young's modulus in the range of about 100 to about 500 MPa and about 0.5 to about 20 MPa, in the longitudinal and transverse directions, respectively. It is believed that more preferred thin ePTFE films possess Young's modulus in the range of about 200 to about 400 MPa and about 1 to about 10 MPa, in the longitudinal and transverse directions, respectively. The most preferred Young's modulus values of the film in the longitudinal and transverse directions are about 300 MPa and about 2 MPa, respectively. This film is exceedingly distensible in the transverse direction.
The choice of film properties is largely dependent on the force the self-expanding stent exerts on the material during expansion. For example, stronger films may be used with stents that exert higher radial forces during self-expansion.
To take advantage of the low Young's modulus of the film, the covered stent may be constructed with the low Young's modulus direction of the film oriented in the circumferential direction of the stent. The high strength direction of the film is therefore oriented in the axial direction of the stent. Preferably, the film is applied to the stent in the shape of a tube. A film tube is constructed by rolling multiple layers of the film around the circumference of a mandrel that is covered with a release material (such as Kapton film, part number T-188-1/1, Fralock Corporation, Canoga Park, Calif.). Preferably, three or fewer ePTFE film layers are applied, more preferably a single layer is applied wherein the overlap seam is narrow and comprises only two layers of the film.
The film tube can be attached to the stent by suturing, gluing, and the like. Gluing is preferred, utilizing an adhesive or combination of adhesives by means such as spraying or dipping. It is preferred to dip coat a fully deployed stent with an adhesive, ensuring that the adhesive does not span the openings in the stent. Thermal or ambient cured adhesives can be used. When bonding the film tube to a shape memory metal stent using a thermally-activated adhesive, the adhesive should be curable at a temperature below the critical transition temperatures of the metal. Adhesives such as perfluoroethylvinylether-tetrafluoroethylene (PEVE-TFE) or perfluoropropylvinylether-tetrafluoroethylene (PPVE-TFE) are preferred. Terpolymers containing at least two of the following monomers are also preferred: PEVE, PPVE, perfluoromethylvinylether (PMVE), and TFE. Most preferably, the adhesive is perfluoromethylvinylether-tetrafluoroethylene (PMVE-TFE) material when bonding the cover to a nitinol stent.
FIG. 2 a depicts a cross-section of the covered stent of the present invention that was constructed at 50% of the fully deployed outer diameter, crimped and transferred inside a delivery catheter, and then deployed to 30% of the fully deployed outer diameter of the device. The stent cover 62 can be attached to the outer surface of the stent by bonding it to stent struts 68 as shown in FIG. 2 a , thereby providing an outer stent cover 51 to the stent 63 . The cover 62 can alternatively be bonded to the inner surface of the stent as shown in FIG. 4 b , providing an inner stent cover 41 .
The most preferred way to attach the film tube to the outer surface of the stent involves placing the film tube inside a rigid (e.g., glass) tube that has an inner diameter smaller than the fully deployed out diameter of the stent, then inserting the crimped stent inside the film tube and bonding the stent and film tube together.
The film tube covering is first inserted inside the constraining tube without creating wrinkles. The ends of the film tube may be everted over the ends of the constraining tube. Preferably the ends are everted to the extent that modest tension is applied to the film tube, enough to hold the film tube taut and thereby keep the film tube free of wrinkles. As has been noted, the inner diameter of the constraining tube, and hence the constraining diameter, should be less than the fully deployed diameter of the device, such as 90% of the fully deployed outer diameter or less, about 80% of the fully deployed outer diameter or less, about 70% of the fully deployed outer diameter or less, about 60% of the fully deployed outer diameter or less, or about 50% of the fully deployed outer diameter or less.
A nitinol stent is prepared by dip coating a thin layer of adhesive to its struts and allowing the adhesive to dry. The preferred adhesive is PMVE-TFE, such as that taught in Example 5 of US Patent Application 2004/0024448 to Chang et al. Contrary to practices in the prior art that teach bonding covers to stents at ambient or even highly elevated temperatures, the cover is applied to the stent at lower than ambient temperatures. Preferably, the stent is chilled and crimped in a cold chamber (e.g., the freezer compartment of a refrigerator). The low temperature process is desired in order to cool the stent in order to dimensionally stabilize it at a diameter less than the film tube diameter while the cover is attached. The crimped stent is next inserted inside the film tube, which is inside a rigid tube. The assembly is permitted to warm to ambient temperature. The stent expands, hence comes in intimate contact with the film tube, as it warms. The assembly is submerged in a solvent that activates the PMVE-TFE adhesive and then warmed above ambient temperature to evaporate the solvent, thus allowing the adhesive to solidify.
The device inside the rigid tube is then again chilled in a freezer to a temperature at which at the device does not self-expand if unconstrained and then the stent-graft is removed from the tube. At this point, the stent-graft is further crimped using the chilled crimping machine, and transferred inside of a delivery catheter. Instead of crimping at this stage, alternatively the porous ePTFE cover of the stent-graft device may be rendered non-permeable. One method to do so can be achieved by dipping the device into a chilled dilute solution of elastomeric material, such as PMVE-TFE, PEVE-TFE, PPVE-TFE, or silicone. A dilute solution is preferred inasmuch as the solution becomes significantly more viscous when chilled to the same temperature as the device. Once the solution dries, the stent-graft can be crimped further, as previously described, and transferred inside of a delivery catheter.
Therapeutic agents, fillers, or the like can be added to the stent cover, the adhesive used to bond the stent cover to the stent or the elastomer material used to render the cover non-permeable or any combination thereof.
Stent-grafts made in this manner exhibit wrinkle-free coverings over the device diameter range extending from the diameter at which the covering was applied up to and including the fully deployed diameter. FIG. 2 b illustrates the wrinkle-free stent cover 62 (in this case, on the outer surface of the stent) at the diameter at which it was bonded to the stent struts 68 , thereby forming the covered stent device 60 . The thin cover 62 stretches and remains wrinkle free up to and including the fully deployed diameter as shown in FIG. 2 c . FIG. 2 c depicts a cross-section of the covered stent of FIG. 1 b . In order to achieve this device performance, the covering should be applied to the stent at a diameter smaller than the fully deployed diameter. This diameter should be no larger than the smallest intended diameter of the implanted device. Crushing the device below the diameter at which the cover was applied induces wrinkles in the stent cover. For example, crushing a device of the present invention to such a degree that it is small enough to be transferred to inside a delivery catheter will induce wrinkles in the stent cover. The wrinkles are no longer present once the deployed stent-graft reaches the diameter at which the cover was applied. Attaching the covering at an intermediate stent size means less crushing is necessary to decrease the stent-graft diameter for insertion into the delivery catheter. The likelihood of perforating the cover during the crushing process is reduced when less crushing is needed.
A stent-graft with an inner cover can be fabricated with a film tube and an adhesive-coated stent as previously described. The stent can be chilled then crushed and constrained inside a constraining tube. The film tube can then be mounted onto a balloon, introduced inside the stent, pressed against the stent via inflating the underlying balloon, then bonded to the stent by immersing the assembly into the appropriate solvent for the adhesive, and then allowed to dry. The balloon is then deflated and the stent-graft plus the constraining tube are again chilled to enable removal of the constraining tube prior to further radial crushing of the stent-graft and loading the device into the delivery system.
The present invention also minimizes flow disturbances caused by blunt stent strut profiles. As seen in FIG. 2 b and FIG. 2 c the adhesive material 22 bonded to stent strut 68 forms a smooth gradual transition where it attaches to stent cover 62 . In the absence of this transition, the stent strut 68 may present a blunt profile to the flowing blood.
The wrinkle-free feature of articles of the present invention can benefit the performance of tapered stent-grafts. Tapered grafts are widely used in the treatment of aortoiliac disease. The present invention, which can include or not include a tapered stent and/or cover, can be implanted inside a tapered vessel without exhibiting wrinkles in the cover. That is, regardless of the shape of the starting materials, the device of the present invention can conform to become a tapered self-expanding stent-graft when deployed within a tapered body conduit. This allows tapered body conduits to be treated with non-tapered devices that are easier and less expensive to construct, without deploying an improperly sized stent-grafts. This also allows for a wider range of effective deployable sizes and shapes without the need to increase the number of different configurations of products.
The present invention has particular value in very demanding, small caliber stenting applications. These are applications in which a cover is needed to either protect against plaque or other debris from entering the blood stream after balloon angioplasty or to seal an aneurysm. Perhaps the most demanding applications are those involving the treatment of carotid and neural vessels where even small wrinkles in the stent cover may create a nidus for thrombosis. Given the sensitivity of the brain, the consequences of such thrombus accumulation and possible embolization can be dire. Not only does the present invention overcome the challenging problem of providing a wrinkle-free cover in a viable stent-graft, it accomplishes this with a surprisingly minimal amount of covering material. It was unanticipated that such a distensible, thin, and low mass material could satisfactorily perform as a stent covering.
The following examples are intended to illustrate how the present invention may be made and used, but not to limit it to such examples. The full scope of the present invention is defined in the appended claims.
EXAMPLES
To evaluate the examples, the following test methods were employed.
Test Methods
Assessment of Wrinkles
Stent-graft device covers were visually examined without the aid of magnification at ambient temperatures. Microscopic examination might be warranted for very small devices. The ends of devices were secured within a hollow DELRIN® acetal resin block in order fix the longitudinal axis of the device at an angle of about 45° above horizontal which enabled viewing the inner surface of the stent-grafts. The devices were positioned to allow examination of free edge of the device and stent openings nearest the ends of the device. Stent-grafts that were not fully deployed were constrained inside rigid tubes during examination. Fully deployed devices were submerged in an about 37° C. water bath prior to examination.
Alternatively, optical or scanning electron microscopy could be used to look for the presence or absence of wrinkles.
Dimensional Measurements
Stent and covered stent device outer diameters were measured with the aid of a tapered mandrel. The end of a device was slipped over the mandrel until the end fit snuggly onto the mandrel. The outer diameter of the device was then measured with a set of calipers. Optionally, a profile projector could be used to measure the outer diameter of the device while so placed on the mandrel.
The fully deployed outer diameter was measured after allowing the self-expanding device to fully deploy in a 37° C. water bath for 30 seconds, then measuring the device diameter in the water bath in the manner previously described.
For devices constrained inside constraining means having a round cross-section, the device outer diameter in the constrained state was taken to be the inner diameter of the constraining means.
In order to examine a device at some percentage of the fully deployed diameter of the device, the fully deployed diameter must first be known. A length of a device can be severed from the entire device and its fully deployed diameter can be measured. For example, a length of the device can be released from the delivery catheter and its diameter measured after being fully deployed in a 37° C. water bath.
Tensile Break Load, Matrix Tensile Strength (MTS), and Young's Modulus Determinations
Tensile break load of the film was measured using a tensile test machine (Model 5564, Instron Corporation, Norwood, Mass.) equipped with flat-faced grips and a 10 N and 100 N load cells for the transverse and longitudinal values, respectively. The gauge length was 1 inch (2.54 cm) and the cross-head speed was 1 in/min (2.54 cm/min). Each sample was weighed using a Mettler AE2000 scale (Mettler Instrument, Highstown, N.J.), then the thickness of the samples was measured using a snap gauge (Mitutoyo Absulute, Kawasaki, Japan). A total of ten samples were tested. Half were tested in the longitudinal direction, half were tested in the transverse (i.e., orthogonal to the longitudinal) direction and the average of the break load (i.e., the peak force) was calculated. The longitudinal and transverse MTS were calculated using the following equation:
MTS =(break load/cross-section area)*(density of PTFE)/bulk density of the film), wherein the density of PTFE is taken to be 2.2 g/cc.
Young's modulus was determined from tensile test data obtained using a tensile test machine (Model 5500, Instron Corporation, Norwood, Mass.). The test was performed using a sample gauge length of 1 inch (2.54 cm) and a cross-head speed of 1 in/min (2.54 cm/min). A total of ten samples were tested. Half were tested in the longitudinal direction, half were tested in the transverse (i.e., orthogonal to the longitudinal) direction.
Inventive Example 1
Tubular, self-expanding nitinol stents constructed using the pattern as described in FIG. 4 of U.S. Pat. No. 6,709,453 to Pinchasik et al., were obtained. The stents had an outer diameter of approximately 8 mm and lengths of about 44 mm. Six sections about 15 mm in length were cut from the stents. Each of the six sections was processed in the following manner. The stent was dip-coated with PMVE-TFE, a liquefied thermoplastic fluoropolymer as described in Example 5 of US Patent Application 2004/0024,448 of Chang, et. al.
A short piece of silver-plated copper wire (approximately 0.5 mm in diameter) was fashioned into a hook and used to suspend the stent. The stent was submerged in a 3% by weight solution of PMVE-TFE and FC-77 solvent (3M Fluoroinert, 3M Specialty Chemicals Division, St Paul, Minn.). The dipped stent was removed from the solution and air-dried. The hook attached to the opposite end of the stent and the dipping process was repeated. The stent was next dipped in a 2% by weight solution of the fluoropolymer and the solvent, then air-dried. Once again, the hook was attached to the opposite end of the stent and the stent was again dipped into the 2% solution. This dipping process, therefore, consisted of four total dips, which yielded a uniform and uninterrupted layer of thermoplastic fluoropolymer on the stent struts. The amount of material applied weighed approximately 0.01 grams as determined by weighing the stent before and after the dipping process.
A stent covering was made as follows. A 4.0 mm stainless steel mandrel was obtained. A 4 mm inner diameter thin-walled (wall thickness of about 0.1 mm) ePTFE tube was fitted over the mandrel. The purpose of this tube was to later assist in removing the stent cover from the mandrel. Next, a spiral wrapping of ribbon of polyimide sheeting (KAPTON®, Part Number T-188-1/1, Fralock Corporation, Canoga Park, Calif.) was applied on top of the ePTFE tube to completely cover a 75 mm length of the graft.
A thin ePTFE film with the following properties was obtained: width of about 50 mm, matrix tensile strength in the longitudinal direction of about 256 MPa, matrix tensile strength in the transverse direction of about 31 MPa, a thickness of 0.02 mm, and a density of about 0.39 g/cc. (The tensile strengths in the longitudinal and transverse directions were 45 MPa and 5 MPa, respectively.) Young's modulus values of the film in the longitudinal and transverse directions were 282 MPa and 1.9 MPa, respectively. An approximately 80 mm length of the film was applied on top of the polyimide sheeting in the axial direction of the mandrel such that the ends of film were in direct contact with the thin-walled ePTFE tube. The corners of these ends were heat bonded to the thin-wall tube with the use of a local heat source (Weller Soldering Iron, model EC200M, Cooper Tools, Apex, N.C.) set to 343° C. With the film tacked in place in this manner, one layer of the film was wrapped about the circumference of the mandrel. Wrapping of the film was performed under minimal tension in order to avoid stretching the film. Approximately a 2 mm width of overlap region was created. The film layers in this overlap region were heat bonded together with the soldering iron set to 343° C. to form a seam. For this construction, therefore, the longitudinal direction of the film, which was its high strength direction, was oriented along the length of the mandrel. The weaker, transverse, film direction was oriented in the circumferential direction of the mandrel.
A second layer of polyimide film was helically wrapped on top of the ePTFE film, completely covering it. This entire assembly was then placed in a forced air oven (Model NT-1000, Grieve Corporation, Round Lake, Ill.) set at 370° C. The assembly was removed from the oven after 7 minutes and allowed to cool. After cooling, the outer wrap of polyimide film was removed. The film tube, inner layer of polyimide film, and the thin-walled ePTFE tube, together, were carefully removed from the mandrel. The thin-walled ePTFE tube was everted, thereby removing it from the polyimide film. The polyimide film was then carefully removed from the ePTFE film tube.
The stent and film tube were next assembled into a stent-graft. The ePTFE film tube was inserted inside a 60 mm long glass tube having an inner diameter of 4 mm and a wall thickness of 1 mm such that both ends of the film tube extended beyond the ends of the glass tube. The ends of closed forceps were then used to spread the ends of the film tube by placing them inside each end of the tube and then opening them. The film tube ends were everted over the outside of the glass tube. The film was tacky enough to secure the ends to the surface of the tube, thereby holding the wrinkle-free film tube in place. The glass tube with the ePTFE film tube inside it was placed in a conventional freezer set at approximately −15° C. Tools that would later be used to create the stent-graft, namely a set of tweezers and an iris-type stent crimping device, such as taught in US 2002/0138966 A1 to Motsenbocker, were also chilled in the freezer compartment.
The chilled crimping device was used to reduce the diameter of the adhesive-coated stent uniformly along its length. The outer diameter of the stent was reduced to about 3 mm. Using chilled tweezers, the following procedure was performed inside the freezer compartment. The stent was removed from the crimper and transferred into the ePTFE film tube that was inside the chilled glass tube. The glass tube, film tube and stent were then removed from the freezer and allowed to warm to ambient temperature. The stent, by virtue of its shape memory characteristics, self-expanded as the assembly warmed. In doing so, the stent exerted radial force against the film tube, creating intimate contact between the stent and the film-tube along the length of the stent.
Next, the stent cover was bonded to the stent. This assembly, still constrained by the 4 mm inner diameter of the glass tube, was then dipped in a container of FC-77 solvent for 40 seconds in order to activate the adhesive. The assembly was then allowed to dry for approximately 30 minutes while being warmed to 40° C. through the use of a halogen lamp. The assembly was allowed to cool to ambient temperature. In this way, a stent-graft device was created.
The stent-graft device was pushed to one end of the glass tube until the end of the stent was flush with the end of the glass tube. The ePTFE covering was trimmed flush with the stent. The process was repeated to trim the opposite end of the stent-graft. With the stent-graft still inside the glass tube, the device was inspected to ensure thorough and uniform bonding between the stent cover and the stent and to verify the absence of wrinkles in the covering.
The next step entailed loading the stent-graft into a delivery system. The stent-graft device, still constrained by the glass tube, was chilled in a freezer as previously described. The device was then transferred to inside a chilled iris crimper and further radially crushed to reduce its outer diameter to the desired delivery profile (i.e., crushed outer diameter), which was about 2 mm. The device was then transferred from the crimper into its intended delivery system. Thus, the device was prevented from self-expanding to its fully deployed outer diameter during the assembly and loading processes.
The resultant stent-graft device had a delivery profile of about 2 mm and a fully deployed outer diameter of 8 mm. Photographs were taken of the device at various stages of deployment and subsequent re-crushing. The outer diameter of the device was characterized as a percentage of the fully deployed outer diameter, which was about 8 mm. The fully deployed device outer diameter was about 8 mm at both about 37° C. and at ambient temperature. It should be noted that this may not be the case for other types of nitinol alloys.
FIGS. 3 a through 3 f are photomicrographs showing the inside of the six covered stents of this example. One device was transferred from its 2 mm delivery profile constraining sheath into a hollowed DELRIN® resin block with an inner diameter corresponding to about 50% of the fully deployed outer diameter of the device. This 50% of the fully deployed outer diameter corresponds to the outer diameter at which the device was made. Photomicrographs were taken of the end of the device as previously described. A representative image is shown as FIG. 3 a . This photomicrograph indicates the absence of wrinkles in the stent covering. Another device was transferred into a hollowed DELRIN® resin block with an inner diameter corresponding to about 60% of the fully deployed outer diameter of the device. A representative image is shown as FIG. 3 b . This photomicrograph indicates the absence of wrinkles in the stent covering. A third device was transferred into a hollowed DELRIN® resin block with an inner diameter corresponding to about 70% of the fully deployed outer diameter of the device. A representative image is shown as FIG. 3 c . This photomicrograph indicates the absence of wrinkles in the stent covering. The fourth and fifth stent-grafts were transferred into hollowed DELRIN® resin blocks with inside diameters of 80% and 90% of the fully deployed outer diameter of the devices, respectively; representative photomicrographs appear in FIGS. 3 d and 3 e , respectively. The coverings were wrinkle-free in both of these states, as indicated in the photomicrographs. The sixth device was fully deployed in a 37° C. water bath and then examined under a microscope. A representative image is shown as FIG. 3 f . This photomicrograph indicates the absence of wrinkles in the stent covering.
Comparative Example 2
Film used in the construction of the six stent-graft devices of Example 1 was used to make a stent-graft in accordance with the teachings of the prior art. The cover was applied to a length of a stent of the type previously-described. In this case, the cover was attached to the stent in the fully deployed state under ambient conditions. The cover was applied in the same manner as described previously. The stent-graft device was then transferred to inside a chilled iris crimper as previously described and further radially crushed to reduce its outer diameter to the desired delivery profile (i.e., crushed outer diameter), which was about 2 mm. The device was then transferred from the crimper into its intended delivery system. Thus, the device was prevented from self-expanding to its fully deployed outer diameter during the assembly and loading processes. The resultant stent-graft device had a delivery profile of about 2 mm and a fully deployed outer diameter of 8 mm. This device was deployed within a hollow DELRIN® resin cavity, as described in Example 1. The diameter of the hole in the block corresponded to about 50% of the fully deployed diameter of the device. A representative photomicrograph of the crushed device appears as FIG. 3 g.
The advantage of making the stent-graft device of the present invention in the above-described manner is clear when comparing FIG. 3 a with FIG. 3 g . Both photomicrographs were taken at 50% of the fully deployed outer diameter. FIG. 3 a , unlike FIG. 3 g , exhibits no wrinkles. FIG. 3 a demonstrates the wrinkle-free benefit of the present invention. On the other hand, FIG. 3 g demonstrates the wrinkles that result from crushing a film tube that was made at 100% of the deployed diameter, then crushed to 50% of the deployed diameter. Note the wrinkles in the leading edge of the cover in FIG. 3 g.
While particular embodiments of the present invention have been illustrated and described herein, the present invention should not be limited to such illustrations and descriptions. It should be apparent that changes and modifications may be incorporated and embodied as part of the present invention within the scope of the following claims. | An improved stent-graft device is provided that delivers a smooth flow surface over a range of operative expanded diameters by applying a unique cover material to the stent through a technique that allows the cover to become wrinkle-free prior to reaching fully deployed diameter. The unique cover material then allows the device to continue to expand to a fully deployed diameter while maintaining a smooth and coherent flow surface throughout this additional expansion. Employed with a self-expanding device, when the device is unconstrained from a compacted diameter it will self-expand up to a fully deployed diameter with the graft being substantially wrinkle-free over diameters ranging from about 30-50% to 100% of the fully deployed diameter. | 54,908 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This invention is related to the technology disclosed in my related U.S. Patent Applications Ser. No. 918,576 filed July 24, 1978, and Ser. No. 092,468 filed Nov. 8, 1979.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a polyphonic digital synthesizer of periodic signals for the production of musical sound. More particularly, it concerns entirely digital synthesizers in which each periodic signal results from a succession of digital samples produced in particular from a wave form sample memory read at variable frequency and then converted into analog form.
2. Description of the Prior Art
Such synthesizers have already been described in French patent applications Nos. 7607419 of Mar. 16, 1976, 7720245 of July 1, 1977, 7832727 of Nov. 21, 1978, and in first certificate of addition number 7907339 of Mar. 23, 1979.
Each sample is produced from a set of digital data such as instantaneous phase, current amplitude (signal envelope), harmonic or octave row, analog output path, etc., which are stored in a block of memories. Each sample therefore results from the reading of a block of memories. This same block is the source of a complete periodic signal, by virtue of the periodic reading of this block and simultaneous updating of the instantaneous phase datum which it contains.
All of the samples of all of the periodic signals are produced sequentially and cyclically in a series which results from connecting the reading of the memory blocks.
Given that a complex output sound can be considered as the sum of a certain number of elementary periodic signals, e.g. sinusoidal, and given the polyphonic nature of the synthesizer, there are numerous memory blocks organized into an assembly called the "virtual keyboard." The synthesizer thereby generates a great number of signals automatically using the data inscribed in the "virtual keyboard."
To make up a complete musical instrument, such as an electric organ, the synthesizer is connected to keyboards, pedals, buttons, stops, and control means which register the data necessary for the generation of signals in the "virtual keyboard," according to actions taken with the keys, buttons, pedals, and stops, and as a function of time. In a quality musical instrument in particular, the development over time of the amplitude of each sound component must be made with great precision and according to given principles. But this need involves considerable work by the control means of the instrument, as well as great complexity of such means and a high cost for the circuits which compose them.
SUMMARY OF THE INVENTION
Accordingly, one object of this invention is to provide a novel synthesizer which avoids the above-noted problem by considerably simplifying the work performed by the control means with regard to the control of the development of each sound component (or periodic signal).
Another object of the present invention is a new synthesizer in which the amplitude of each sound component is capable of developing automatically over time between an initial running value and a given final value, according to a given principle, and of doing so without intervention of the instrument's control means, at least until the final amplitude value has been reached.
According to one characteristic of the invention, the synthesizer comprises:
plural generators of rectangular signals of given frequencies;
a set of memory blocks containing at least instantaneous phase data, octave or harmonic row data, and amplitude data;
control means for reading the memory blocks sequentially and in a given series which is a function of the generator signals;
means for producing analog samples of periodic signals from the data read in the blocks; and
means for automatically developing, as a function of time, the amplitude of each periodic signal, comprising computation means for periodically replacing the amplitude datum of each block which contains one with a new amplitude datum computed by interpolation between the initial amplitude and a predetermined final amplitude.
For example, one or more amplitude clock generators determine the rhythm of computation of the new amplitude values.
According to another characteristic of the invention, each block containing a running amplitude datum further contains a final amplitude datum which serves periodically for the computation of the new running amplitude. The development of the amplitudes of the different periodic signals is thus mutually independent.
According to the invention, therefore, the amplitude datum in the virtual keyboard block is automatically modified at the rhythm of the amplitude clock (very low frequency) according to an essentially linear or logarithmic interpolation. The logarithmic (or exponential) interpolation, in particular, enables a very gentle and natural development of the amplitude between the initial and final values to be obtained, without the listener sensing a stepwise amplitude development. The amplitude clock is completely independent of the rectangular signal generators which determine the frequencies of the elementary tones. Several amplitude clocks are even desirable so as to make available a great variety of amplitude development speeds.
Given that this amplitude development is carried out automatically by the synthesizer, the instrument's control means are now required only to furnish several points of the amplitude envelope curve of the periodic output signals, which simplifies the task of the control means considerably and enables the general qualities of the instrument to be greatly improved.
According to a preferred embodiment of the invention, the means used for automatic development of amplitude may be common with other of the synthesizer's computational means, limiting the complexity of the circuits. These means may also be blocked at any time by the instrument's outside control means, thus suspending automatic operation and leaving the possibility of creating special effects to the instrument control means.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:
FIG. 1 is a block diagram of the general structure of a synthesizer according to the invention;
FIG. 2 is a detailed circuit diagram of the automatic amplitude development circuits and the control circuits of the invention;
FIG. 3 is a graph illustrating an amplitude development curve running from an initial to a final value;
FIG. 4 is a graph illustrating a complete curve of the development of the amplitude of a sound component; and
FIG. 5 is a flow chart explaining the progress of operations within the synthesizer.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the drawings, wherein like reference numerals designate identical or corresponding parts throughout the several views, and more particularly to FIG. 1 thereof, the synthesizer of the invention includes as an essential element "virtual keyboard" 2, which is a set of memory blocks, each containing digital parameters used for generating a sample of a periodic signal. The virtual keyboard consists, for example, of a memory composed of 256 blocks of 7 memories each. The contents of each of the memories of the blocks will be set forth clearly in the following. The blocks are read one by one, sequentially and according to a given series. The contents of the seven memories of each block are read simultaneously and applied to the other circuits of the synthesizer. They occasion the production of a sample and/or the updating of a datum contained in the virtual keyboard (running amplitude, instantaneous phase).
The virtual keyboard is therefore the basic element of the synthesizer since it contains both the data necessary for the production of successive samples of elementary signals and address pointers enabling sequential reading of the blocks in a given series. The position of each block in the virtual keyboard is defined by an address. This position may vary. It is decided by the synthesizer's outside control means. The position of each datum in a block is, by contrast, constant, with each memory coupled to one or more specific circuits of the synthesizer.
There are therefore two types of blocks in virtual keyboard 2: main blocks and secondary blocks.
Each main block contains an instantaneous phase value Ψ which is automatically incremented in substantial synchronization with the signal of a generator designated within the block by a number I. The block also contains a primary pointer PP, i.e. the address of another main block, a secondary pointer PS, i.e. the address of a secondary block, and a block type identification bit T (e.g. T=1 for a main block). Each secondary block contains digital data relating to octave O, wave form and type F, analog output path selection V, running amplitude AC, final amplitude AF, and selection of amplitude clock generator VA. It further contains a bit M for validation or restriction of automatic amplitude development, a secondary pointer PS, i.e. the address of another block (either main or secondary), and a block type identification bit T (T=0 for a secondary block).
Memory 10 contains the bit for identification of each type of block (T=1 or 0).
Memory 11 contains secondary pointer PS for the two types of blocks.
Memory 12 contains either primary pointer PP, where a main block is concerned, or data M, VA and AF where a secondary block is concerned.
Memory 13 contains either instantaneous phase Ψ (main block) or running amplitude AC (secondary block). This particular memory enables the circuits for incrementation of phase Ψ and variation of amplitude AC to be combined, these circuits having the same connection to the virtual keyboard.
Memory 14 contains either frequency generator number I (main block) or output path number V (secondary block).
Memories 15 and 16 contain respectively either the numbers for waveform F or octave O where a secondary block is concerned, or no significant data, in the case of a main block. These positions are of course available for containing data for eventual supplementary operations.
The significance of the data delivered by virtual keyboard V thus depends on the type of block read, i.e. on indicator T read in memory 10. The unfolding of operations within the synthesizer is thus directly tied to the reading of the blocks according to a set series, or chain, as described with reference to the following FIG. 5.
This unfolding is automatic, but it is nevertheless conditioned by the content of memories 11 and 12 (pointers), and determined by the control means of the instrument (not shown) and by the rectangular signals of a certain number of generators.
The control means of the musical instrument (not shown) communicate with the synthesizer through a set of connections called a "bus" 1. The controls of the synthesizer thus amount to read and write operations in the virtual keyboard from bus 1.
Selection of the blocks of the virtual keyboard is made by an address register 3, likewise connected to bus 1. This register is, in fact, a buffer register supplied with an address furnished either by the bus or by a selector circuit 4 which receives the two address pointers of the virtual keyboard, primary pointer PP of memory 12 and secondary pointer PS of memory 11. Selection depends on a selection control signal delivered by command logic 6 of the synthesizer. Turnover of the addresses in buffer register 3 occurs at the rhythm of a clock 5 or of a clock or control signal which determines the frequency of recurrence of the block read operations and consequently the frequency of production of samples of the elementary signals. However, the choice and order of production of the samples depends both on the content of the memory blocks, particularly the pointers, and on rectangular signal generators 7 and 8.
A set of generators 7 of rectangular signals determines the frequencies of the synthesizer's elementary signals. Set 7 contains at least 12 generators, the frequencies of which are fixed and distributed over a chromatic range. Generally, set 7 contains other generators, e.g. controllable frequency generators, enabling the synthesizer to produce signals of variable frequencies as well as special effects. These generators are connected to control logic 6 which, in keeping with the sequence for reading the blocks of virtual keyboard 2, detects changes in state in the generators and orders the updating of phase data Ψ and the production of analog samples.
A set of generators 8 determines the speed of amplitude development of the elementary signals. The frequencies of generators 8 are very low (several hertz to several hundred hertz). These generators are likewise connected to control logic 6, which, again in keeping with the sequence for reading the blocks of the virtual keyboard, detects generator state changes and orders the updating of amplitude data AC.
In order to do this, the control logic receives, in addition to signals from generators 7 and 8, block type identification bit T, the current address delivered by register 3, validation bit M, speed VA for selection of one of generators 8, number I for selection of one of generators 7, the least significant bit (Ψ o or A o ) of the current phase Ψ or amplitude datum AC, and a signal "=" indicating the equality AC=AF.
Depending on the state of all of these signals, logic 6 delivers an order "≠" for updating the current datum Ψ or AC, an order for selection of a primary or secondary pointer to selector 4, and call signals IT and ADR for the synthesizer's outside control means, through BUS 1.
The generation of elementary tones by successive samples is thus done from the above-mentioned control signals (T, ≠) and the date read in the virtual keyboard.
Computation circuit 20 performs either the incrementation and memorization of phase Ψ or the updating of current amplitude AC as a function of final amplitude AF.
An address computation circuit 21 receives phase and waveform and octave numbers F and O, and delivers an address which is applied to a waveform memory 22. The latter delivers a digital instantaneous amplitude sample (or amplitude variation sample) to a digital-analog converter element 23. The analog sample obtained is multiplied, in circuit 24, by the digital current amplitude datum AC and the result applied to a demultiplexing circuit 25 controlled by path selection datum V. Circuit 25 includes several analog output paths 26 intended to be connected to amplifiers through filtering and amplitude adjustment circuits which are not shown.
Circuits 21 to 25 are constructed very simply. Circuits 21 and 22 are read only memories, for example. Circuits 23 and 24 consists, for example, of two digital-analog converters connected in series, the output of one being connected to the reference input of the other. Circuit 25 is a demultiplexing circuit.
FIG. 2 represents the details of control logic 6 and of circuit 20 for updating phase and amplitude data.
These circuits function from data read in the virtual keyboard, of which only memories 14, 10, 12 and 13 have been represented, along with address register 3 and selector 4.
The control logic comprises two multiplex circuits 60 and 61. Circuit 60 receives the rectangular signals delivered by the series of generators 7 (e.g. 16 different frequencies) which determine the frequencies of the periodic output signals. Circuit 61 receives the rectangular signals of the series of generators 8 (e.g. eight frequencies) which determine the speed of development of the amplitude of the periodic signals.
Multiplexer 60 therefore outputs the rectangular signal designated by the number I delivered by memory 14 when the block read is a main block (T=1). If not, i.e., if T=0, the output is disconnected (high impedance). Similarly, multiplexer 61 receives datum VA from memory 12 and delivers the signal from the corresponding generator when T=0. In order to do this, datum T (one bit) is applied directly to circuit 60 and, through an inverter gate 64, to circuit 61. The two multiplexer outputs are connected to one input of an exclusive-OR gate 65, the other input of which receives the least significant bits Ψ o (if T=1) or A o (if T=0). The output of gate 65 thus delivers an active ≠ signal if the states of the input signals are different and an inactive signal if they are identical. Each time the "≠" signal is active, it induces an updating of phase datum Ψ or amplitude datum AC (incrementation of the phase or interpolation of the amplitude). This updating must be performed in such a way that the least significant bit of Ψ OR AC is always identical to the state of the generator selected by one of the multiplexers. As long as there is equality, gate 65 will not order an updating.
This updating is carried out by circuit 20, which comprises:
a first three-input, eight bit adder 35. A first input is connected to memory 13 and thus receives phase Ψ (if T=1) or current amplitude AC (if T=0). A second input permanently receives a logic state 1 (1L). A third input is connected to the output of an AND circuit 34;
a second two-input, four bit adder 33. A first input receives the four most significant bits of memory 13 following inversion by an inverter 32. A second input receives the four bits of final amplitude AF. The output of adder 33 is connected to a non-inverting input of AND circuit 34. The other input of AND 34 is inverting and receives signal T;
a comparator circuit 31 receiving the contents of memories 12 and 13 delivering an "=" signal as soon as there is identity.
For the operation of circuit 20, two cases are possible, according to the value of T:
If T=1, the data read in memory 13 is phase Ψ. The binary state of the output of AND 34 is still 0. Consequently, the output of adder 35 delivers Ψ+1. This datum is placed in memory in a register 36 so as to be available (for circuit 21) when the datum read in memory 13 is amplitude AC. Datum Ψ+1 is likewise registered in memory 13 in place of preceding datum Ψ. The order of memorization is given by the "≠" signal delivered by exclusive-OR 65.
If T=0, it is datum AC which is delivered by memory 13. The four most significant AC bits at input Y 1 of circuit 32 represent AC/16. Considering similarly that datum Y 2 at the input of adder 33 is AF/16, since memory 12 has only 4 bits, adder 33 delivers:
Y.sub.3 =Y.sub.2 -Y.sub.1 =(AF-AC)/16-1
This datum is applied to adder 35 across AND 34, which is open when T=0, with a left shift of one bit, corresponding to a multiplication by two:
Y.sub.4 =2Y.sub.3
The output of adder 35 thus delivers:
Y.sub.5 =AC+Y.sub.4 +1=AC+2(AF-AC)16-1
This operation performs two functions:
a logarithmic interpolation between AC and AF:
a reversal of least significant bit A o , since the quantity added, 2(AF-AC)/16-1, is odd.
Control logic 6 further comprises an AND circuit 66 performing Tx≠ in order to control selector circuit 4. In fact, as long as ≠ is in state 0, the type of block selected does not change, as long as the states of generators 7 do not change, the blocks read remain main blocks, and no sample is computed. If the reading of a series of secondary blocks is in question, T=0 and the "≠" signal has no effect on selector 4. The series of secondary blocks follows its sequence until a main block appears, as will be explained below.
The control logic further comprises an address memory 63 intended to register the address of the block in which there exists the equation AC=AF. In order to do this, the "=" signal delivered by comparator 31 is applied to a logic circuit 62 intended to govern the end of amplitude development in each block. This circuit receives signals T, M (1 bit), "=", and address ADR in memory 63. It delivers memorization control signals to memory 63, multiplexer M blocking signals, and IT interruption signals to the synthesizer's outside control circuits through BUS 1. The IT signal is accompanied by the contents ADR of memory 63. The latter also receives through bus 1 a signal RAZ for clearing its contents. Logic 62 is made up simply of a programmable network (read only memory). The outputs deliver control signals as a function of input signals in accordance with the following truth table, in which the symbol x means "don't care, 1 or 0":
______________________________________M T ADR = Commands______________________________________1 x x x No commandx 1 x x No command0 0 ≠0 x Transmission of IT No memory in 63 Blocking of multiplexer 610 0 =0 0 No IT signal No memorization in 63 Unblocking of multiplexer 610 0 =0 1 Transmission of signal IT Memorization of ADR in 63 Blocking of multiplexer 61______________________________________
FIG. 3 represents the automatic development of the amplitude of a periodic output signal over time t from an initial amplitude to a final amplitude. It shows an increasing signal and a decreasing signal. The amplitude of each signal in fact develops by steps. The points on each curve indicate the new running amplitude AC.sub.(n+1)t calculated from the running amplitude at the preceding point AC nt and final amplitude AF, according to the formula:
AC.sub.(n+1)t =AC.sub.nt +(AF-AC.sub.nt)/k
with the coefficient k preferably being a power of 2 (k=4 in the case of the Figure).
FIG. 4 represents the amplitude envelope curve of a periodic signal. This curve comprises a leading section t 0 -T 1 where the amplitude is rising, a section T 1 -T 5 where the signal undergoes an amplitude tremolo, and a section T 5 -T 6 , etc., involving diminution and extinction of the signal. It should be noted that this complex evolution of amplitude requires only a few amplitude commands (writing new value AF), at instants T1, T2, T3, etc.
FIG. 5 is a flow chart explaining the unfolding of the sequence for reading of blocks within the synthesizer.
As long as the state of the signals from generators 7 does not change, reading of main blocks proceeds without production of any samples, along loop 100-101-100, etc., which comprises selection of a principal pointer 101, reading of a designated main block (100), and a test of the generator designated by the number I which it contains. If the state of a generator changes (≠), phase Ψ of the main block is incremented (103). The following block, designated by the secondary pointer (102), is first made the object of a test (104). If this block is a main one, there is a return to 101; if it is not a main one, the state of generator 8 designated by datum V A is tested (105).
A sample is then computed automatically (107), either using the running amplitude value AC already contained in the block (if there is state change as indicated by the "=" sign) or using a new running amplitude (if "≠") computed (106) according to a logarithmic (or exponential, or linear) interpolation. Then a new block is selected by the secondary pointer (102) and so on.
The invention is applied to electronic musical instruments of which it constitutes the principal element. In fact, the production of an instrument such as an electric organ requires other elements surrounding the synthesizer, such as cabinet, keyboards, pedals, electric power supply, low frequency amplification and synthesizer control logic. This control is advantageously composed of a microcomputer, of which the synthesizer according to the invention is a peripheral. This microcomputer, moreover, is very simple and comprises a microprocessor connected to program memories, data memories, and logic circuits making the necessary connections with keyboards, pedals, buttons, stops, etc., as well as with the synthesizer. Several synthesizers may even be coupled to one microcomputer and vice-versa.
By automatically carrying out the automatic development of the envelope of each periodic signal up to a final amplitude value, the synthesizer according to the invention frees the microcomputer from the corresponding task. The complexity of the synthesizer is not substantially increased, however, since the phase incrementation and amplitude computation circuits are joint, with the characteristic that each updating operation of phase or amplitude adds an odd quantity to the preceding value, so that the least significant bit may follow the state of a generator. Other equivalent means are obviously foreseeable. It should also be noted that the automatic amplitude development of each periodic signal is independent of that of other signals. Thus, certain periodic signals may be modified from time to time by the control means of the instrument while others may keep the same amplitude, in two possible ways, either by ignoring the IT signal transmitted by control logic 6, or by placing a mask M in memory 12 of the virtual keyboard. This mask M prevents logic 62 from transmitting an IT signal to the microprocessor, but does not prevent the operation of the means (20) for updating the running amplitude. The running amplitude value meanwhile remains constant and equal to AF. Mask M may also be used to block the operation of updating means 20.
Obviously, numerous additional modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended Claims, the invention may be practiced otherwise than as specifically described herein. | An entirely digital polyphonic musical synthesizer in which the amplitude of each spectral component may develop either linearly or logarithmically as a function of time, including amplitude computation means which produce, for each period of an amplitude clock signal, a new current amplitude value by linear or logarithmic interpolation between the initial current amplitude and a predetermined final amplitude value. The new current amplitude value is memorized in place of the initial value. When the current amplitude is equal to the final amplitude, a signal is transmitted to the synthesizer control means. The synthesizer enables gentle modulations in amplitude to be obtained and reduces the complexity of the instrument's control means. | 26,662 |
BACKGROUND
[0001] The applicant's prior published patent application GB2,494,435A discloses a communication system which utilises a guiding medium which is suitable for sustaining electromagnetic surface waves. The contents of GB2,494,435A are hereby incorporated by reference. The present application presents various applications and improvements to the system disclosed in GB2,494,435A.
BRIEF SUMMARY
[0002] In a first aspect, the present invention provides a communications system, comprising: a surface wave channel for guiding electromagnetic surface waves; a transmitter, coupled to said surface wave channel for transmitting signals along said surface wave channel; one or more disrupters, arranged to be positioned at arbitrary locations on or adjacent said surface wave channel, and arranged to convert said surface wave signals to space wave signals; and one or more receiver terminals, arranged to be positioned at locations corresponding to said disrupters, each terminal comprising an antenna for receiving said space wave signals.
[0003] In a second aspect, the present invention provides a surface wave to space wave converter, comprising: a surface wave collector; and an antenna; wherein the surface wave collector is coupled to the antenna; the surface wave collector is arranged to collect surface wave signals from a surface wave channel; and the antenna is arranged to radiate said signal as a space wave.
[0004] Further examples of features of the present invention are recited in the claims.
DESCRIPTION OF THE DRAWINGS
[0005] Embodiments of the present invention will now be described, by way of example only, and with reference to the accompanying drawings, in which:
[0006] FIG. 1 shows a communications system in accordance with an embodiment of the present invention;
[0007] FIG. 2 shows a surface wave launcher for use with the system of FIG. 1 ;
[0008] FIG. 3 shows further details of the surface wave launcher of FIG. 2 ; and
[0009] FIG. 4 shows a surface wave to space wave converter in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
[0010] FIG. 1 shows a communications system 100 in accordance with an embodiment of the present invention. The system 100 includes a surface wave channel 101 . The surface wave channel may take the form of the surface wave channels disclosed in the applicant's published UK patent application, GB2,494,435A. In particular, the surface wave channel has a high surface impedance, and is suitable for guiding electromagnetic surface waves. The channel 101 is elongate, and is generally arranged to guide surface waves in the direction of its length. The channel may be made of a dielectric coated conductor, corrugated surface, or any other material which has a high surface impedance suitable for the transmission of electromagnetic surface waves.
[0011] The system 100 further comprises a surface wave launcher 102 . The surface wave launcher 102 is arranged to convert electrical signals to surface wave signals. Further details of a suitable launcher are provided in GB2,494,435A, and are also described below. The system 100 also includes a server 103 . The server 103 is coupled to the surface wave launcher 102 by connection 104 . The server 103 is includes a transmitter, and is arranged to transmit data along the surface wave channel 101 . The surface wave launcher 102 converts signals received from the server 103 to surface wave signals.
[0012] The system 100 also includes a plurality of disrupters 105 A, 105 B, 105 C. The disrupters may be positioned at arbitrary positions along the surface wave channel. The disrupters are arranged to disrupt the surface wave signals, and to cause the surface wave signals to be scattered as space waves. In the present embodiment, the disrupters 105 A, 105 B, 105 C are metallic plates, which act as reflectors. The metallic plates are positioned on the surface wave channel so that they are perpendicular to the surface. They are orientated to cause specular scattering at an angle of ninety degrees to the direction of the channel. In order to achieve this, the plates are orientated at a forty five degree angle. In use, when a surface wave hits the plate, it is reflected as a space wave. The reflectors may be arranged to reflect the surface waves towards the edge of the channel 101 , where they reradiate as space waves. Alternatively, the reflectors may be arranged to reflect the surface waves upwards, away from the surface.
[0013] The system 100 also includes a plurality of user terminals 106 A, 106 B, 106 C. Each user terminal is coupled to an antenna 107 A, 107 B, 107 C. The antennas are arranged to receive the space waves reflected from the disrupters 105 A, 105 B, 105 C. As such, in use, the antennas and their corresponding user terminals are positioned in close proximity to the positions of the corresponding disrupters. In particular, the antennas 107 A, 107 B, 107 C are positioned close enough to the disrupters so that they may adequately receive the space wave signals.
[0014] The user terminals 106 A, 106 B, 106 C may include a user interface which may include a display. The terminals may therefore be arranged to display data sent by the server 103 . One application of this system may be in a television broadcast system. For example, the system may be used as an in-flight entertainment system on a passenger airplane.
[0015] In use, the server 103 broadcasts a data signal which may include multimedia data to be viewed by the user terminals 106 A, 106 B, 106 C. The signal is converted to a surface wave by surface wave launcher 102 . The surface wave propagates along the surface wave channel 101 . The disrupters 105 A, 105 B, 105 C are positioned such that only some of the surface wave is reflected, the remainder propagating along the surface channel towards the other disrupters. The reflected surface wave propagates as a space wave towards a corresponding antenna 107 A, 107 B, 107 C. The space wave is then converted to an electrical signal by the corresponding antenna. The converted signal is then received by the corresponding user terminal 106 A, 106 B, 106 C.
[0016] FIG. 2 shows an example of a surface wave launcher which may be used with the system 100 shown in FIG. 1 . FIG. 2 shows a surface wave launcher 200 in accordance with a first embodiment of the present invention. The surface wave launcher includes a parallel-plate waveguide 201 and a feed section 202 . The waveguide 201 includes a feed end 203 and a launch end 204 . The feed section 202 is coupled to the waveguide 201 as the feed end 203 . The feed section includes a coaxial cable 205 . The coaxial cable includes an inner conductor 206 , an insulating layer 207 and an outer conductor 208 . The feed section 202 also includes a coupling pin 209 which is connected to the inner conductor 206 at an end of the coaxial cable.
[0017] The waveguide 201 is a rectangular cuboid. The waveguide 201 includes a first planar conductor 210 , which is forms an upper surface of the waveguide. The first planar conductor 210 forms an isosceles triangle, the top vertex of which is connected to the coupling pin 209 . The waveguide 201 also includes a dielectric layer 211 , positioned below the first planar conductor 210 , and which is also a rectangular cuboid. The dielectric 211 is preferably low loss for the frequency of operation. The waveguide 201 also includes a second planar conductor (not shown in FIG. 2 ), which is positioned behind the dielectric layer 211 . The second planar conductor is rectangular in shape, and completely covers the underside of the dielectric 211 .
[0018] FIG. 3 shows a cross-section through launcher 200 . The features of the launcher 200 are labelled in the same manner as in FIG. 2 . In FIG. 3 , the second planar conductor 212 is shown. The outer conductor 208 of the coaxial cable 205 is coupled to the second planar conductor 212 .
[0019] FIG. 3 also shows a guiding medium 213 with which the surface wave launcher 200 is arranged to operate. The guiding medium may be similar to that described in the applicant's previously published UK patent application GB2,494,435A. The guiding medium 213 includes a dielectric layer 214 and a conductive layer 215 . Together they form a dielectric coated conductor with a reactive impedance which is higher than the resistive impedance. Such a surface is suitable for the propagation of electromagnetic surface waves. In use, the launcher 200 can be placed at a shallow angle to the surface of a guiding medium 213 to launch waves in a particular direction. The performance of the launcher 200 at a particular frequency can be optimised by changing the length of the triangle.
[0020] The surface wave launcher 200 may also operate in reverse, as a surface wave collector. Furthermore, the system 100 may operate in reverse, with user terminals transmitting signals which are reflected by the disrupters onto the surface wave channel, to generate surface waves.
[0021] As noted, above the system 100 includes a number of disrupters. FIG. 4 shows a surface wave to space wave converter 300 in accordance with an alternative embodiment of the present invention. The converter 300 includes a surface wave collector 301 and an antenna 302 . An output of the surface wave collector 301 is coupled to an input of the antenna 302 . The collector 301 may take the form of the surface wave launcher described above in connection with FIGS. 2 and 3 . As noted there, the surface wave launcher may operate in reverse as a surface wave collector. In use, the waveguide of the surface wave collector is positioned against the surface wave channel 101 . The collector 301 collects surface waves and converts them to electrical signals which are sent to the antenna 302 . The antenna 302 then radiates a corresponding space wave which may be received by a user terminal. The antenna 302 may take many forms. For example, it can be directional or omni-directional depending on the requirements of the system.
[0022] In an alternative embodiment of the present invention, the converter 300 may be used to transmit a space wave signal to another converter, which then launchers a surface wave onto a further surface wave channel. This embodiment could be used where it is not possible to lay a surface wave channel, for example where a gap needs bridging.
[0023] In the above-described embodiments, surface wave launchers and surface wave collectors have been described. These devices may in fact identical in construction. However, in use, the device will either act to “collect” surface waves, or to “launch” surface waves. The terminology used above has been selected dependent on the context in which the device is being used. It will be appreciated that in some contexts, the devices may be used for both purposes, even though they are referred to as either collectors or launchers.
[0024] Features of the present invention are defined in the appended claims. While particular combinations of features have been presented in the claims, it will be appreciated that other combinations, such as those provided above, may be used.
[0025] Further modifications and variations of the aforementioned systems and methods may be implemented within the scope of the appended claims. | A communications system, comprising: a surface wave channel for guiding electromagnetic surface waves; a transmitter, coupled to said surface wave channel for transmitting signals along said surface wave channel; one or more disrupters, arranged to be positioned at arbitrary locations on or adjacent said surface wave channel, and arranged to convert said surface wave signals to space wave signals; and one or more receiver terminals, arranged to be positioned at locations corresponding to said disrupters, each terminal comprising an antenna for receiving said space wave signals. | 11,899 |
CROSS REFERENCE TO RELATED PATENT
U.S. Pat. No. 4,107,792.
BACKGROUND OF THE INVENTION
This invention relates to an apparatus for the discontinuous mixing of at least two materials, at least one of which is a liquid. More particularly, the invention relates to a mixing apparatus which includes a container and a mixer disposed therein, the mixer having a first rotor which is driveable at high speed through a shaft, and a second rotor which replaces a stator and is driven at a lower speed, both the first rotor and the stator having teeth which cooperate by being positioned on mutually concentric but axially separate circles and which move past one another on circles of different radii to define shearing slots.
An apparatus of the type to which this invention relates and of which it is an improvement is described in U.S. Pat. No. 4,107,792. It is a particular feature of the mixing apparatus described in the aforementioned patent that the radially farther outward circle of teeth on the rotor is disposed outside of the radially outwardly located circle of teeth on a stator. It has been found in the arrangement of the rotor relative to the stator as described in the aforementioned patent that, when solids are dispersed in liquids, the dispersal time is reduced to one fifth of the time required when using previously known types of apparatus. The total amount of energy required for a mixing process is simultaneously reduced by 75 to 80 percent of the energy expenditure which would otherwise be required. By disposing the radially outwardly lying circle of teeth of the rotor externally of the radially outwardly lying circle of teeth of the stator, the individual material particles and drops of fluid acquire a high tangential acceleration due to contact with the radially outwardly lying teeth of the rotor after passing the radially outwardly lying shear slots. The high tangential acceleration leads to the formation of pronounced circular flow patterns which guide all the small particles and/or droplets more often into the rotor-stator system so that all the particles are subjected to very high hydrodynamic shear stresses. Many other advantages and favorable effects are derived from the disposition of stator and rotor as described in the aforementioned patent and these descriptions are incorporated in the present disclosure by reference. One of the advantages of the design according to the U.S. Pat. No. 4,107,792 is that cavitation phenomena develop in the shearing slots between the rotor and the stator. Advantageously also, the teeth of the rotor and the corresponding teeth of the stator have the same axial extent and are mounted parallel to each other. Preferably, the teeth on both rotor and stator are in the form of pins.
The use of mixing apparatus in practice has shown that the dispersal of thixotropic materials in fluids is made more difficult because the above-mentioned well-defined circular fluid flows did not appear.
In order to improve the mixing characteristics for thixotropic materials, it has been proposed in a prospectus entitled "Drais Planetary Kneader Mixers", published by Draiswerke GmbH, West Germany, to mount the radially most outwardly lying row of teeth on the stator and, in addition thereto, to provide supplementary mixing tools driven by planetary gears, each supplementary mixing tool being attached to one planetary gear of the planetary gear train. Furthermore, movable strippers are disposed in the vicinity of the interior wall of the container.
The use of this planetary mixer which employs the combination of a movable scraper or stripper, together with the above-described principal mixer consisting of a rotor and stator, has shown that the mixing of thixotropic materials remains unsatisfactory.
SUMMARY OF THE INVENTION
It is thus a principal object of the present invention to provide an apparatus for mixing at least two materials with a decreased energy input and a reduction of the mixing time. It is an associated object of the present invention to provide a mixing apparatus in which the aforementioned advantages are obtained when at least one of the materials to be mixed is a thixotropic material.
The foregoing object as well as others which are to become clear from the text below, is achieved according to the invention by virtue of the fact that the mixing apparatus is provided with a second rotating shaft coaxial with and rotating in the same sense as the principal rotating shaft carrying the first rotor, and wherein the secondary rotating shaft carries a unit which replaces the stator as well as a scraper located and moving in the vicinity of the interior wall of the mixing container. The unit, hereinbelow referred to as a second rotor rotates at a lower angular velocity than the conventional rotor, hereinbelow referred to as the first rotor. It has been found, surprisingly, in using the apparatus of the invention which includes, in addition to the first rotor and the second rotor, only scrapers rotating slowly in the vicinity of the interior wall of the container but does not include any supplementary mixing tools, that the forced mingling of the materials is optimized. A possible explanation for this fact is that the supplementary mixing tools, for example the aforementioned planetary mixing tools, may actually disturb and diminish the circular fluid flows generated by the rotor-rotor system, whereas these circular flows are enhanced when only scrapers are present. It should be noted that the construction according to the present invention is advantageous even when non-thixotropic materials are mixed and will lead to a substantial reduction of the mixture time because all of the particles and droplets of the materials to be mixed participate in the forced motion in a statistically more uniform manner so that each particle or droplet completes the required number of passages through the shearing slots of the rotor-rotor system substantially sooner. The second rotor of the present invention actually rotates but its speed of rotation is substantially slower than that of the first rotor and has consequently stator-like characteristics to a considerable degree.
Advantageously, the second rotating shaft carrying the second rotor and the wall scraping attachment is a hollow shaft which coaxially surrounds the principal drive shaft of the first rotor.
Advantageously, the speed of rotation of the principal shaft is 7-70 times greater than the speed of rotation of the drive shaft to which the second rotor and the wall scraper are attached. In an advantageous feature of the invention, the radial extent of the scraper increases toward the top of the container, thereby causing an increased flow of materials toward the central shaft in the vicinity of the top part of the container.
BRIEF DESCRIPTION OF THE DRAWINGS
Further advantages and features of the invention will be apparent from the description of an embodiment with reference to the drawing.
The single FIGURE of the drawing is a side-elevational view of an apparatus for mixing materials according to the invention in partial vertical cross section. Reference numerals referring to parts identical with those of FIG. 1 in U.S. Pat. No. 4,107,792 are marked with primes.
DESCRIPTION OF THE PREFERRED EMBODIMENT
An apparatus for mixing materials according to the present invention is provided with a substantially cylindrical container 1' open at the top, into which a mixer 2' is inserted from above. The mixer 2' is provided with a shaft 4' on a suspension mount in a housing 3' indicated generally, the shaft being driveable at high speed by a drive motor 40. The lower, free end of the shaft 4' carries first rotor 17' consisting of a hub 18' coupled to the end of the shaft 4' and, extending therefrom, substantially radial, propeller-like rotor arms 21' the ends of which carry an annular disc 23'. Mounted vertically on the disc 23' are teeth 24' in the form of pins disposed parallel to one another at regular intervals around the periphery of the disc 23'. An annular disc 11' which is part of a second rotor unit 8' is disposed in the plane defined by the upper ends of the teeth 24' and also carries a row of equally spaced teeth 12' in the form of pins. The pins 12' extend downwardly from the annular disc 11' to the immediate vicinity of the surface of the annular disc 23'. The annular disc 11' of the second rotor 8' is held in its position by arms 41 disposed substantially parallel to the principal rotor shaft 4' and attached at their other end to a hollow shaft 42 which is concentric with and surrounds the shaft 4' of the first rotor 17'. The sense of rotation of the hollow shaft 42 is the same, as indicated by the arrow 43, as the sense of rotation of the shaft 4' of the first rotor 17' as indicated by the arrow 20'.
Further attached to the hollow shaft 42 is a radially extending carrier arm 44 whose radially remote, free end carries a downwardly extending scraper 45 having a radially remote scraping edge 46 which may be in contact with the interior cylindrical wall 47 of the container 1' or at least lies in the immediate vicinity of that surface. The scraping attachment 45 may be rotated about an internal axis 48, thereby adjusting its angular position with respect to the carrier arm 44 as well as with respect to the prevailing tangent to the interior wall 47 of the container 1'. The hollow shaft 42 carrying the scraper 45 and the second rotor 8' is also rotated by the drive motor 40 at a constant speed which, depending on the dimensions of the apparatus may lie between 10 and 25 rpm.
The rotational speed of the central shaft 4' which carries the first rotor 17' is substantially higher. The higher speed of rotation of the shaft 4' is obtained by the interposition of a steplessly controllable transmission (not shown) located within the housing 3'. In very large installations, the speed range which may be selected is between 150 and 500 rpm, whereas it may be for example between 500 and 1500 rpm in relatively small installations.
The preferred rotational speed of the shaft 4' and its first rotor 17' is thus seen to be from 7-70 times greater than the speed of rotation of the hollow shaft 42 carrying the second rotor 8' and the scraper 45.
The relative disposition of the stator teeth 12' and the rotor teeth 24' is as described in U.S. Pat. No. 4,107,792. As stated therein, the teeth 24 are in the form of pins having the same diameter and the same length as the teeth 12, also made in the form of pins. The two sets of teeth overlap in their lengthwise directions, as seen in FIG. 1 so that, when one tooth 24' on the rotor 17' passes the tooth 12' on the second rotor 8', a shearing slot is formed whose width can be several millimeters. The teeth 12', 24', are positioned axially parallel to the axis of rotation 28' of the shaft 4'. Similarly, the effects due to this disposition of the teeth and due to the relatively rapid rotation of the rotor teeth 24' which radially surround the rotor teeth 12', are virtually the same as obtained in the apparatus described in the aforementioned patent. Due to the high circumferential speed of the first rotor 17', which may be as high as 50 m/sec, the materials in the container 1' acquire a very high tangential acceleration which tends to generate a well-defined circular flow which is illustrated in the figure by flow lines 29' and 30'. It will be appreciated that, while the figure shows only those components of motion of the flow which occur in a vertical section, the motion would actually have rotational components which cannot be shown. In practice, the flow pattern is invariably three-dimensional. The existence of these flow patterns is further enhanced by the presence of the scraper 45 due to the fact that the scraper 45 increases the return flow of particles from the radially outward region of the container 1' toward the central shaft 4'. This return flow leads to an increased circulation of the individual particles so that they tend to pass the shearing slots formed between the teeth 12' and 24' still more often than would otherwise be the case. Furthermore, the presence of the scraper 45 prevents the deposition of any material on the wall 47, which materials might otherwise be lost to the forced circulation. The increased return flow due to the scraper is the result of an increase in the radial extent of the scraper toward the top of the container. In the simplest embodiment, the scraper 45 has a lower region 45a and an upper region 45b of greater radial extent than the lower region. Accordingly, the scraper exerts increased return flow forces on the fluid toward the central axis 28' in a region where the flow would tend to be the least agitated. The fact that both shafts rotate in the same sense brings the advantage that the scraper does not have to operate in opposition to the established rotational flows described above but moves in the same direction as these flows, thereby substantially reducing the energy requirements for driving the hollow shaft 42 carrying the scraper 45 and the second rotor 8'.
The housing 3' which houses the drive motor 40, the shaft 4' and the hollow shaft 42 may be mounted in known manner on a pedestal 49 whose height may be adjustable, permitting the housing 3' to be moved upwardly as far as necessary to remove the mixing system 2' completely from the container 1'. The open top of the container 1' may be closed by a cover 51 mounted on a non-rotatable guide tube 50 concentrically surrounding the hollow shaft 42. The cover 51 may also be moved axially by means of a hydraulic drive mechanism 52. The cover 51 may be vacuum-sealed with respect to the container 1' in known manner. The cover 51 is provided with a vacuum sealable filler opening 53 and an evacuation valve 54. The lower part of the container 1' has an outlet valve 55.
Due to the construction of the mixing apparatus of the present invention, which includes a slowly rotating scraper 45, it is no longer necessary, as was heretofore required, to cause the mixer 2' to execute an axial oscillatory (up and down) motion within the container 1'. This oscillatory motion required a substantial expenditure and introduced substantial sealing problems during vacuum operation because of the requirement of having to seal the cover 51 with respect to the shaft 4' in both rotary and axial motion. Accordingly, the construction of the present invention is particularly advantageous when the mixing apparatus is used in vacuum operation.
It is to be understood that the foregoing description as well as the accompanying drawing relate to an illustrative embodiment of an apparatus set out by way of example and not by way of limitation. Numerous other embodiments and variants are possible without departing from the spirit and scope of the invention. | An apparatus for discontinuous mixing of substances, one of which is a liquid and especially suitable for the mixing of thixotropic materials. The mixer has a high speed rotor which cooperates with a more slowly rotating stator. Both rotor and stator are provided with teeth disposed on mutually concentric circles. When the teeth move past one another, shearing slots are formed. The drive shaft carrying the stator also carries at least one radially extending arm on which is mounted a wall scraper whose angle of attack with respect to the wall may be changed by rotation about an internal axis. | 15,343 |
PRIORITY
[0001] This application claims the benefit under 35 U.S.C. §119(a) of a Korean patent application filed in the Korean Intellectual Property Office on Jul. 5, 2011 and assigned Serial No. 10-2011-0066623, the entire disclosure of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The preset invention relates to a method and apparatus in which a device terminal accesses a coordinator terminal in a communication system. More particularly, the present invention relates to a system and method supporting efficient operations of a plurality of sensor devices that periodically transmit sensing information in a Body Area Network (BAN).
[0004] 2. Description of the Related Art
[0005] Wireless Body Area Network (WBAN), which is under standardization as an international standard called Institute of Electrical and Electronic Engineers (IEEE) 802.15.6 TG6 BAN, aims to provide medical services such as telemedicine services over a communication network formed around three meters or less from the body, and to provide entertainment services in which wearable equipment for wearable computing or motion sensors are used. In addition, WBAN is under similar standardization as an international standard called IEEE 802.15.4j Medical BAN (MBAN), and 802.15.4j is defined as an amendment standard for using the existing 802.15.4 in a Medical BAN Service (MBANS) band of 2.36˜2.4 GHz.
[0006] WBAN generally includes a coordinator and a plurality of devices such as various types of sensors attachable to the body.
[0007] The main application of WBAN is to collect biometric information from medical sensors and to send the collected biometric information to medical institutions. A coordinator, which has a wire or wireless communication line connected to a medical institution server, sends data received from devices or sensors connected by WBAN to the medical institution server. For example, the coordinator may send the data received from the devices or sensors in an unprocessed form or after analyzing such data.
[0008] In the WBAN healthcare system, because small-sized devices equipped with a mobile power supply such as a battery are mainly handled, reducing (e.g., minimizing) the power consumption of the devices is an important system requirement. Generally, a low duty cycling technique may be applied, for low-power implementation. As an example, the small-sized devices may be sensors having poor power conditions.
[0009] FIG. 1 shows a data transmission process when it is operated by low duty cycling and when a beacon is used in an IEEE 802.15.4 WBAN according to the related art.
[0010] Referring to FIG. 1 , when the data transmission process is operated by low duty cycling, the lower the duty cycling, the greater the number of nodes that have data during an inactive period. At the starting point of the next active period, the system attempts to transmit all of the data.
[0011] As described above, in the WBAN according to the related art, when data is transmitted by low duty cycling, many nodes may have data during an inactive period due to the low duty cycling. Consequently, transmission of all of this data is attempted in the next active period.
[0012] In this case, the WBAN according to the related art may deal with contention with the fixed initial backoff settings, for packet transmission. However, when the concentration of traffic is severe, it is difficult to solve this problem with the initial backoff settings which were made without recognizing this problem.
[0013] In addition, when a number of packet transmission attempts rapidly increases in the next active period, the packet transmission attempts are concentrated at the same time in a Contention Access Period (CAP). Accordingly, traffic may occur during the packet transmission.
[0014] Therefore, a need exists for an apparatus and method for controlling resource access by devices such that in a WBAN in which periodic data transmission is made, a plurality of devices may be prevented from causing a reduction in performance such as delays due to their excessive collisions in a Contention Access Period CAP
[0015] The above information is presented as background information only to assist with an understanding of the present disclosure. No determination has been made, and no assertion is made, as to whether any of the above might be applicable as prior art with regard to the present disclosure.
SUMMARY OF THE INVENTION
[0016] Aspects of the present invention are to address at least the above-mentioned problems and/or disadvantages and to provide at least the advantages described below. Accordingly, an aspect of the present invention is to provide a system and method for controlling resource access by devices such that in a Wireless Body Area Network (WBAN) in which periodic data transmission is made, a plurality of devices may be prevented from causing a reduction in performance such as delays due to their excessive collisions in a Contention Access Period (CAP).
[0017] In accordance with an aspect of the present invention, a coordinator in a Mutual Broadcast Period (MBP) and CAP operating system for load control is provided. The coordinator includes a Radio Frequency (RF) unit for broadcasting a beacon frame, and a controller for determining whether contention for data transmission in a CAP due to backlogged traffic increases, by recognizing the number of connected devices, for broadcasting a beacon frame including information about an MBP used for load control to each device through the RF unit before the CAP if the contention for data transmission increases, for determining whether a load control broadcast message for determining existence of data load is received in the MBP from the device without error, and for sending a response to the load control broadcast message to the device.
[0018] In accordance with another aspect of the present invention, a device in a MBP and CAP operating system for load control is provided. The device includes a RF unit for receiving a beacon frame broadcasted from a coordinator, and a controller for sending a load control broadcast message for determining existence of data load to the coordinator in an MBP based on information about the MBP upon receiving a beacon frame including information about an MBP used for load control from the coordinator before a CAP, for determining a type of a CAP depending on whether sending of the load control broadcast message is successful and whether packet transmission by other devices is successful, and for performing data transmission using a CAP corresponding to the determined CAP type.
[0019] In accordance with another aspect of the present invention, a method for operating a MBP and CAP for load control in a coordinator is provided. The method includes determining whether contention for data transmission in a CAP due to backlogged traffic increases, by recognizing the number of connected devices, broadcasting a beacon frame including information about an MBP used for load control to each device before the CAP, if the contention for data transmission increases, determining whether the load control broadcast message is received without error, and sending a response to the load control broadcast message to the device.
[0020] In accordance with another aspect of the present invention, a method for operating a MBP and CAP for load control in a device is provided. The method includes receiving a beacon frame including information about an MBP used for load control from a coordinator before a CAP, sending a load control broadcast message for determining existence of data load to the coordinator in the MBP based on information about the MBP, determining a type of a CAP depending on whether sending of the load control broadcast message is successful and whether packet transmission by other devices is successful, and performing data transmission using a CAP corresponding to the determined CAP type.
[0021] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings, in which:
[0023] FIG. 1 shows a data transmission process when it is operated by low duty cycling and when a beacon is used in an IEEE 802.15.4 Wireless Body Area Network (WBAN) according to the related art;
[0024] FIG. 2 shows a structure of a superframe including a Mutual Broadcast Period (MBP) according to an exemplary embodiment of the present invention;
[0025] FIG. 3 shows a superframe configured by dividing an MBP into Mutual Broadcast Zones (MBZs) and a Contention Access Period (CAP) into Contention Access Zones (CAZs) according to an exemplary embodiment of the present invention;
[0026] FIG. 4 shows a structure of one MBZ according to an exemplary embodiment of the present invention;
[0027] FIG. 5 shows a structure of a coordinator and a device according to an exemplary embodiment of the present invention;
[0028] FIG. 6 shows a structure of a beacon frame according to an exemplary embodiment of the present invention;
[0029] FIG. 7 shows a structure of an MBP field according to a first exemplary embodiment of the present invention;
[0030] FIG. 8 shows a structure of a superframe including the MBP field and having no GTS according to the first exemplary embodiment of the present invention;
[0031] FIG. 9 shows a structure of a superframe including the MBP field and having a GTS according to the first exemplary embodiment of the present invention;
[0032] FIG. 10 shows a structure of an MBP field according to a second exemplary embodiment of the present invention;
[0033] FIG. 11 shows a structure of a superframe according to the second exemplary embodiment of the present invention;
[0034] FIG. 12 shows a structure of an MBP field according to a third exemplary embodiment of the present invention;
[0035] FIG. 13 shows a structure of an MBP field according to a fourth exemplary embodiment of the present invention;
[0036] FIG. 14 shows a structure of a superframe according to the third exemplary embodiment of the present invention;
[0037] FIG. 15 shows a structure of a superframe according to the fourth exemplary embodiment of the present invention;
[0038] FIG. 16 shows a process of performing load control using an MBP according to an exemplary embodiment of the present invention;
[0039] FIGS. 17A and 17B show a flow diagram of a Carrier Sense Multiple Access-Collision Avoidance (CSMA-CA) algorithm in an Exclusive CAP according to an exemplary embodiment of the present invention;
[0040] FIGS. 18A and 18B show a flow diagram of a CSMA-CA algorithm in a Background CAP according to an exemplary embodiment of the present invention;
[0041] FIG. 19 shows a process of performing load control using an MBP in a coordinator according to an exemplary embodiment of the present invention; and
[0042] FIG. 20 shows a process of performing load control using an MBP in a device according to an exemplary embodiment of the present invention.
[0043] Throughout the drawings, in should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0044] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention as defined by the claims and their equivalents. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary. Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions may be omitted for clarity and conciseness.
[0045] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention is provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.
[0046] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a component surface” includes reference to one or more of such surfaces.
[0047] FIG. 2 shows a structure of a superframe including a Mutual Broadcast Period (MBP) according to an exemplary embodiment of the present invention.
[0048] Referring to FIG. 2 , the superframe includes a beacon frame B, an MBP, a Contention Access Period (CAP), and a Contention Free Period (CFP).
[0049] In an exemplary embodiment of the present invention, the MBP is established between the beacon frame B and the Contention Access Period (CAP) as shown in FIG. 2 . Thus, before entering the CAP, devices may exchange information with each other, thereby ensuring proper load control in the CAP.
[0050] Queue information about the number of packets accumulated thus far is sent in the MBP, thereby preventing transmission attempts from being concentrated at the same time in the CAP.
[0051] In the exemplary embodiment of the present invention, load control in the CAP is made naturally in a distributed manner depending on the information that the devices have exchanged in the MBP.
[0052] According to exemplary embodiments of the present invention, the MBP is smaller than the CAP in time period. As example, with regard to a length of the MBP, the coordinator may inform the devices of the length of the MBP by adding a field indicating the length of the MBP in the beacon frame B and including information about the length of the MBP or information about a start point of the CAP in the added field. This MBP operates by Carrier Sense Multiple Access-Collision Avoidance (CSMA-CA) similarly to the CAP, but the MBP may be set so as to consider light contention situations such as making a length of a backoff slot short because the MBP does not require transmission of a lot of data.
[0053] FIG. 3 shows a superframe configured by dividing an MBP into Mutual Broadcast Zones (MBZs) and a CAP into Contention Access Zones (CAZs) according to an exemplary embodiment of the present invention.
[0054] Referring to FIG. 3 , the superframe includes a beacon frame B, an MBP, and a CAP. The MBP includes at least one MBZ and the CAP includes at least one CAZ.
[0055] Exemplary embodiments of the present invention propose MBZs and CAZs, for balanced load control. An MBZ corresponds to each of N zones obtained by dividing an MBP. Similarly, a CAZ corresponds to each of N zones obtained by dividing a CAP. MBZs correspond to CAZs on a one-to-one basis.
[0056] For example, assume that the coordinator sets 6 MBZs in an MBP and 6 CAZs in a CAP.
[0057] These MBZs and CAZs are used as a tool for load balancing, through load control. As an example, MBZ # 1 corresponds to CAZ # 1 , MBZ # 2 corresponds to CAZ # 2 , and in this way, MBZ # 6 corresponds to CAZ # 6 .
[0058] One MBZ will be described in detail with reference to FIG. 4 .
[0059] FIG. 4 shows a structure of one MBZ according to an exemplary embodiment of the present invention.
[0060] Referring to FIG. 4 , one MBZ includes a plurality of mini backoff slots. When attempting to transmit data in an MBZ, a device transmits data at the boundary of a mini backoff slot in accordance with a slotted CSMA-CA operation.
[0061] According to exemplary embodiments of the present invention, the data that a plurality of devices attempt to send in one MBZ, includes queue information of each device, and a device detects transmission by other devices based on the slotted CSMA-CA operation, and transmits data by a backoff algorithm. However, when there are a large number of devices, the devices may not transmit data in an MBZ.
[0062] FIG. 5 shows a structure of a coordinator and a device according to an exemplary embodiment of the present invention.
[0063] Referring to FIG. 5 , a coordinator 100 includes a controller 101 , a Radio Frequency (RF) unit 102 , and a memory 103 , and a device 110 includes a controller 111 , an RF unit 112 , a sensing unit 113 , and a memory 114 .
[0064] According to exemplary embodiments of the present invention, if the controller 101 in the coordinator 100 expects an increase in contention by data transmission in a CAP due to backlogged traffic by recognizing the number of connected devices, the controller 101 informs the devices of the expected increase in contention by including MBP information in a beacon frame B. For example, the MBP information includes a period length and the number of MBZs.
[0065] Thereafter, upon receiving a queue information packet sent for load control from the device 110 without error, the controller 101 sends a response or an Acknowledgement (ACK) to the device 110 . If there is traffic that the coordinator 100 desires to send to the device 110 , the controller 101 sets a destination address as a broadcast address, sends a broadcast message to the broadcast address, and sends no ACK to the device 110 that has received the broadcast message. The queue information packet includes an indicator indicating a control packet sent in an MBP, and may further include a queue length associated with Quality of Service (QoS), a traffic type, a battery status, and the like. The queue information packet includes queue information in terms of other utilizations of an MBZ, and in fact, only for load control resource access, the queue information may be minimized or not. The queue information packet may be called a ‘load control broadcast message’.
[0066] The RF unit 102 in the coordinator 100 broadcasts a beacon frame B, and sends an ACK to the device 110 upon receiving a queue information message from the device 110 .
[0067] The memory 103 in the coordinator 100 stores information used for data transmission, and may store MBP information such as a period length and the number of MBZs.
[0068] Next, the controller 111 in the device 110 obtains MBP information from the coordinator 100 , finds the required amount of resources needed for packet transmission, and then determines the number of CAZs based thereon. Thereafter, the controller 111 arbitrarily selects one or multiple MBZs, the number of which corresponds to the found number of CAZs, from among all MBZs.
[0069] To transmit a packet in a CAP, the controller 111 first transmits a message packet including queue information to the coordinator 100 in a mini backoff slot at an MBZ point selected from a total of N MBZs in an MBP.
[0070] Upon receiving an ACK from the coordinator 100 , the controller 111 determines whether to use a CAZ corresponding to the MBZ as an Exclusive CAP, and stores it in the memory 114 . Upon receiving no ACK from the coordinator 100 , the controller 111 retries the packet transmission, considering that a Negative Acknowledgement (NACK) is received. If the transmission in the selected MBZ is not successful, the controller 111 selects again one of the remaining unselected MBZs. The term ‘Exclusive CAP’ as used herein may refer to a period in which the device 110 may transmit more data than an amount of data, which is set by default.
[0071] While not transmitting its queue information packet in the selected MBZ, the controller 111 receives queue information packets from other devices in a listening state, and upon receiving ACKs for the queue information packets from the coordinator 100 , the controller 111 stores the queue information packets in the memory 114 . This may be used when the controller 111 adjusts CSMA-CA variables in a CAP.
[0072] The controller 111 performs listening only, in the unselected MBZs. If there is no queue information packet that the device 110 has transmitted in the MBZ and received an ACK therefor, the controller 111 determines to use a CAZ corresponding to the MBZ as a Normal CAP. The term “Normal CAP’ as used herein may refer to a period in which the device 110 may transmit data in the amount of data, which is set by default.
[0073] If the device 110 fails to transmit the queue information packet in all MBZs, the controller 111 determines to use the full CAP as a Background CAP. The term ‘Background CAP’ as used herein may refer to a period in which the device 110 may transmit data in the remaining period among the entire data transmission period.
[0074] The RF unit 112 in the device 110 is configured to transmit and receive information. For example, the RF unit 112 receives a beacon frame broadcasted from the coordinator 100 , transmits a queue information packet to the coordinator 100 in each MBZ corresponding to each CAZ, and receives an ACK from the coordinator 100 .
[0075] The sensing unit 113 in the device 110 outputs sensed data to the controller 111 .
[0076] The memory 114 in the device 110 stores information needed for data transmission, and may store the queue information packet received from the coordinator 100 . The memory 114 stores in advance CAP information corresponding to the transmission results of the queue information packet. For example, the CAP information includes an Exclusive CAP, a Normal CAP and a Background CAP.
[0077] As a result, exemplary embodiments of the present invention may enable efficient resource access by performing load control in a distributed manner for data transmission/reception, contributing to a reduction in access delay and power consumption and enabling appropriate QoS control.
[0078] A structure of the above-described beacon frame B will be described in detail below with reference to FIG. 6 .
[0079] FIG. 6 shows a structure of a beacon frame according to an exemplary embodiment of the present invention.
[0080] Referring to FIG. 6 , the beacon frame includes a field for Frame Control, a field for Sequence Number, an Addressing field, an Auxiliary Security Header, a field for Superframe Specification, a Pending address field, a Beacon Payload, an MBP field, a Frame Check Sequence (FCS). The beacon frame may also include a GTS field.
[0081] According to exemplary embodiments of the present invention, it is appropriate for the MBP field to include variable fields, similarly to GTS fields, rather than the Superframe Specification field giving information, because the MBP field is a field newly added to the existing specification. Details and structure of the MBP field will be described in detail below with reference to FIGS. 7 to 15 .
[0082] FIG. 7 shows a structure of an MBP field according to a first exemplary embodiment of the present invention.
[0083] A MBZ/CAZ Count field (with 4 bits, having a value of 0 to 15) indicates the number of MBZs/CAZs.
[0084] A MBZ Length field indicates a length of one MBZ on a slot basis.
[0085] A CAZ Length field indicates a length of one CAZ on a slot basis.
[0086] Referring to FIG. 7 , if MBZ/CAZ Count is 3, MBZ length is 1, and CAZ length is 4, then slots # 0 to # 2 operate as an MBP, slots # 3 to # 14 operate as CAZs corresponding to MBZs, and the remaining slot # 15 may operate as a Normal CAP.
[0087] Two different types of superframes including the MBP field according to a first exemplary embodiment of the present invention may be represented as shown in FIGS. 8 and 9 . FIG. 8 shows a type of a superframe without GTS, and FIG. 9 shows a type of a superframe to which GTS is applied.
[0088] FIG. 8 shows a structure of a superframe including the MBP field and having no GTS according to the first exemplary embodiment of the present invention. FIG. 9 shows a structure of a superframe including the MBP field and having a GTS according to the first exemplary embodiment of the present invention.
[0089] Referring to FIG. 8 , the superframe includes a beacon frame, an MBP, and a CAP. The MBP includes at least one MBZ and the CAP includes at least one CAZ.
[0090] Referring to FIG. 9 , the superframe includes a beacon frame, an MBP, and a CAP, and a GTS. For example, the GTS may be included in a Circuit Emulation over Packet (CEP). The CEP may include a plurality of GTSs.
[0091] FIG. 10 shows a structure of an MBP field according to a second exemplary embodiment of the present invention.
[0092] Referring to FIG. 10 , the MBP field includes an MBZ/CAZ Count, an MBZ Ending Slot, and a CAZ Ending Slot.
[0093] MBZ Ending Slot indicates the last slot among the existing 16 available slots, which is to be used for an MBP.
[0094] CAZ Ending Slot indicates a slot of the last CAZ in a CAP.
[0095] Although a first exemplary embodiment of the present invention is similar to a second exemplary embodiment of the present invention, when the CAZ Ending Slot is not defined, a CAP from the next slot of MBZ Ending Slot to the final CAP slot of the Superframe Specification field will be divided by a number in the MBZ/CAZ Count field in the same length.
[0096] When the CAZ Ending Slot is defined, if the CAZ Ending Slot is greater than the final CAP slot, it is regarded as the same value as that of the final CAP slot, and a CAP from the next slot of MBZ Ending Slot to CAZ Ending Slot will be divided by a number in the MBZ/CAZ Count field in the same length. In this case, a CAZ length will not be a multiple of a superframe slot. An MBP from 0 to MBZ Ending Slot is also divided by a number in the MBZ/CAZ Count field in the same length and used as MBZ field.
[0097] When the MBP field according to a second exemplary embodiment of the present invention is used, for each MBZ/CAZ, a CAP from the next slot of MBZ Ending Slot to a superframe slot designated by CAZ Ending Slot will be divided by a number in the MBZ/CAZ Count field in the same length.
[0098] A superframe including the MBP field according to the second exemplary embodiment of the present invention may be represented as shown in FIG. 11 .
[0099] FIG. 11 shows a structure of a superframe according to the second exemplary embodiment of the present invention.
[0100] Referring to FIG. 11 , the superframe includes a beacon field, an MBP, a CAP, and a GTS. The MBP field includes at least one MBZ, and the CAP includes at least one CAZ. As an example, the GTS may be included in a CFP.
[0101] In addition, MBP Duration (MD) determined by an MBP Order value rather than based on the superframe slot as in the above-described first and second exemplary embodiments of the present invention may be configured with an MBP. An MBP Order field is a field used to adjust a size of the superframe, and an MBP Order value may be determined by the user or the coordinator's algorithm, like the superframe order or beacon order, and may have 2 bits in an exemplary embodiment of the present invention.
[0102] The configured MBP fields may be represented as shown in FIGS. 12 and 13 .
[0103] FIG. 12 shows a structure of an MBP field according to a third exemplary embodiment of the present invention, and FIG. 13 shows a structure of an MBP field according to a fourth exemplary embodiment of the present invention.
[0104] Referring to FIG. 12 , the MBP field includes an MBP Order, an MBZ/CAZ Count, and a CAZ Length.
[0105] Referring to FIG. 13 , the MBP field includes an MBP Order, an MBZ/CAZ Count, and a CAZ Ending Slot.
[0106] Similarly to Superframe Duration (SD) and Beacon Interval (BI), MD may be calculated by Equation (1) below.
[0000] MD =aBaseSuperframeDuration*2 MO symbols (1)
[0107] An MBP is inserted as a new period ahead of a CAP before a start of a superframe slot # 0 depending on the calculated MD, and other fields in the MBP field according to the third and fourth exemplary embodiments of the present invention are the same as those in the MBP field according to the first and second exemplary embodiments of the present invention.
[0108] Superframes including the MBP fields according to the third and fourth exemplary embodiments of the present invention may be represented as shown in FIGS. 14 and 15 .
[0109] FIG. 14 shows a structure of a superframe according to the third exemplary embodiment of the present invention, and FIG. 15 shows a structure of a superframe according to the fourth exemplary embodiment of the present invention.
[0110] Referring to FIG. 14 , the superframe includes a beacon field, an MBP, a CAP, and a GTS. The MBP may include at least one MBZ, and the CAP may include at least one CAZ. As an example, the GTS may be included in a CFP.
[0111] Referring to FIG. 15 , the superframe includes a beacon field, an MBP, a CAP, and a GTS. The MBP may include at least one MBZ, and the CAP may include at least one CAZ. As an example, the GTS may be included in a CFP.
[0112] An operation of the device will be described in detail below with reference to FIG. 16 .
[0113] FIG. 16 shows a process of performing load control using an MBP according to an exemplary embodiment of the present invention.
[0114] According to exemplary embodiments of the present invention, if a plurality of devices attempt transmission of a queue information packet in one MBZ, all or some of the attempting devices may succeed in the attempts, or all of the attempting devices may fail in the attempts.
[0115] When all of the attempting devices succeed in the attempts, all of the devices operate in a CAP corresponding to an Exclusive CAP (E-CAP). However, when there are a large number of devices, only some of the devices may succeed in the attempts generally, because it will be unlikely that all of the devices may succeed in the attempts. Some devices having succeeded in the attempts may operate in a CAP corresponding to an Exclusive CAP, but the remaining devices having failed in the attempts may not use the associated CAZs. If all of the devices have failed in their respective attempts, the devices having made the attempts may not use the associated CAZs. However, the devices, which have been performing listening instead without making the attempts, may use the associated CAZs as a Normal CAP. The devices, which have finally failed in transmission in an MBP because they have failed in transmission in all MBZs where they attempted the transmission, may use the entire CAP as a Background CAP.
[0116] Referring to FIG. 16 , it is assumed that a superframe is divided into 6 CAZs in a CAP and 6 MBZs in an MBP, and as the coordinator broadcasts this information to devices, the devices recognize the information in advance.
[0117] For example, in a case in which first and fourth devices delivered a Queue (Q) information packet to the coordinator in MBZ # 1 among 6 MBZs in an MBP, second, third and fifth devices determine to transmit data using a Normal CAP N-CAP at CAZ # 1 in a CAP, when no ACK is received from the coordinator.
[0118] In a case in which second and fifth devices delivered a Q information packet to the coordinator in MBZ # 2 among 6 MBZs in an MBP, the second and fifth devices determine to transmit data using an Exclusive CAP E-CAP at CAZ # 2 in a CAP upon receiving an ACK from the coordinator.
[0119] In a case in which first and fifth devices delivered a Q information packet to the coordinator in MBZ # 3 among 6 MBZs in an MBP, only the fifth device determines to transmit data using an Exclusive CAP E-CAP at CAZ # 3 in a CAP, if no ACK is received at the first device from the coordinator and an ACK is received at the fifth device from the coordinator.
[0120] In a case in which a first device delivered a Q information packet to the coordinator in MBZ # 4 among 6 MBZs in an MBP, only the first device determines to transmit data using an Exclusive CAP E-CAP at CAZ # 4 in a CAP if an ACK is received at the first device from the coordinator.
[0121] In a case in which third and fourth devices delivered a Q information packet to the coordinator in MBZ # 5 among 6 MBZs in an MBP, first, second and fifth devices determine to transmit data using a Normal CAP N-CAP at CAZ # 5 in a CAP if no ACK is received from the coordinator.
[0122] In a case in which third and fourth devices delivered a Q information packet to the coordinator in MBZ # 6 among 6 MBZs in an MBP, only the third device determines to transmit data using an Exclusive CAP E-CAP at CAZ # 6 in a CAP, if an ACK is received at the third device from the coordinator and no ACK is received at the fourth device from the coordinator.
[0123] The fourth device, which has failed in transmission of a Q information packet at all of 6 MBZs in an MBP, determines to transmit data using a Background CAP (B-CAP) in a CAP.
[0124] As described above, an operation in a CAP is based on the CSMA-CA resource access scheme which is defined according to each of the Exclusive CAP, Normal CAP and Background CAP determined in an MBP in advance. Although the detailed operation in each period will not be described herein, it is general that an Exclusive CAP may be set for a device to attempt resource access more strongly than usual, and a Background CAP may be set for a device to attempt resource access more weakly than usual. In this regard, the Exclusive CAP, Normal CAP and Background CAP may have, for example, the following variables and algorithms. Specifically, CSMA-CA algorithms, in which the foregoing is reflected, will be described with reference to FIGS. 17A , 17 B, 18 A and 18 B. Operations on the CSMA-CA algorithms in FIGS. 17A , 17 B, 18 A and 18 B are the same as an operation of the general CSMA-CA algorithm, and variables and algorithm setting values by the Exclusive CAP and Background CAP will be applied as described below.
[0125] FIGS. 17A and 17B show a flow diagram of a CSMA-CA algorithm in an Exclusive CAP according to an exemplary embodiment of the present invention.
[0126] Referring to FIG. 17A , at step 1701 it is determined whether a CSMA-CA operation is a slotted CSMA-CA operation. If it is a slotted CSMA-CA operation, then the process proceeds to step 1708 . At step 1708 , the NB may be set such that NB=0, and CW may be set such that CW=2. Upon setting NB and CW, the process proceeds to step 1709 . At step 1709 , it is determine whether battery life extension is required. If battery life extension is not required, then the process proceeds to step 1710 at which BE may be set such that BE=less of (2, macMinBE) and thereafter the process proceeds to step 1712 . If at step 1709 , it is determined that battery life extension is required, then BE may be set such that BE=macMinBE at step 1711 . Thereafter, the process proceeds to step 1712 . At step 1712 , the back off period boundary is located and the process proceeds to step 1713 . At step 1713 , a delay for a random number of backoff periods is performed. For example, the delays may be such that a delay of random(2 BE -1) unit backoff periods is performed. After the delay, the process proceeds to step 1714 at which a CCA on backoff period boundary is performed and the process proceeds to step 1715 . At step 1715 , it is determined whether a channel is idle.
[0127] Referring to FIG. 17A , if the channel is determined to be idle at step 1715 , the process proceeds to step 1716 at which an Exclusive CAP is set less than a Normal CAP in terms of setting values: macMinBE and macMaxBE, and in a BE incremental equation in step 1716 , BE may be set such that BE=min(BE+0.5, macMaxBE), and maxCSMAbackoffs is set large. In an NE incremental equation in step 1716 , NB may be set such that NB=NB+0.5. When NB or BE is used, their integers may be taken and used. After step 1716 , the process proceeds to step 1717 at which it is determined whether NB is greater than macMaxCSMABackoffs. If NB is not greater than macMaxCSMABackoffs, then the process returns to step 1713 . If NB is greater than macMaxCSMABackoffs, then the process ends in failure.
[0128] If the channel is determined to not be idle at step 1715 , then the process proceeds to step 1718 at which CW may be set such that CW=CW-1. After the CW is set, the process proceeds to step 1719 at which it is determined whether CW=0. If CW is determined to not equal 0, then the process returns to step 1714 . However, if CW is determined to equal 0, then the process ends in success.
[0129] Referring to FIGS. 17A and 17B , if at step 1701 it is determined that the CSMA-CA operation is not slotted, then the process proceeds to step 1702 . At step 1702 , the NB may be set such that NB=0 and ME may be set such that BE=macMinBe. Thereafter, the process proceeds to step 1703 at which a delay is performed. As an example, the delay may be for a number of unit backoff periods corresponding to random(2 BE -1). Thereafter, the process proceeds to step 1704 at which a CCA is performed. After performing the CCA, the process proceeds to step 1705 at which it is determined whether the channel is idle. If the channel is determined to be idle at step 1705 , then the process proceeds to step 1706 at which NB may be set such that NB=NB+0.5 and BE may be set such that BE=min(BE+0.5, macMaxBE). Thereafter, the process proceeds to step 1707 at which it is determined whether NB is greater than macMaxCSMABackoffs. If it is determined that NB is not greater than macMaxCSMABackoffs, then the process returns to step 1703 . If NB is determined to be greater than macMaxCSMABackoffs, then the process ends in failure.
[0130] Conversely, if at step 1705 it is determined that the channel is idle, then the process ends in success.
[0131] According to exemplary embodiments of the present invention, a Normal CAP is the same as macMinBE, macMaxBE, and maxCSMAbackoffs values used by the existing CSMA-CA algorithm in a CAP. BE has min([BE+1], macMaxBE) and NB has NB+1.
[0132] FIGS. 18A and 18B show a flow diagram of a CSMA-CA algorithm in a Background CAP according to an exemplary embodiment of the present invention.
[0133] Referring to FIG. 18A , at step 1801 it is determined whether a CSMA-CA operation is a slotted CSMA-CA operation. If it is a slotted CSMA-CA operation, then the process proceeds to step 1808 . At step 1808 , the NB may be set such that NB=0, and CW may be set such that CW=2. Upon setting NB and CW, the process proceeds to step 1809 . At step 1809 , it is determine whether battery life extension is required. If battery life extension is not required, then the process proceeds to step 1810 at which BE may be set such that BE=less of (2, macMinBE) and thereafter the process proceeds to step 1812 . If at step 1809 , it is determined that battery life extension is required, then BE may be set such that BE=macMinBE at step 1811 . Thereafter, the process proceeds to step 1812 . At step 1812 , the back off period boundary is located and the process proceeds to step 1813 . At step 1813 , a delay for a random number of backoff periods is performed. For example, the delays may be such that a delay of random(2 BE -1) unit backoff periods is performed. After the delay, the process proceeds to step 1814 at which a CCA on backoff period boundary is performed and the process proceeds to step 1815 . At step 1815 , it is determined whether a channel is idle.
[0134] Referring to FIG. 18A , if the channel is determined to be idle at step 1815 , the process proceeds to step 1816 at which a Background CAP is set greater than a Normal CAP in terms of setting values: macMinBE and macMaxBE. In a BE incremental equation in step 1816 , BE may be set such that BE=min(BE+2, macMaxBE), and maxCSMAbackoffs may be set small. In an NB incremental equation in step 1816 , NB may be set such that NB=NB+2.
[0135] NB corresponds to the number of retries due to a backoff made at one access attempt. CW is the number of backoff periods needed to check whether the channel is in an idle state. BE is related to the number of backoff intervals for which a device should wait before performing channel sensing, and the device may select any number from among numbers of 0 to 2BE-1 before its operation.
[0136] After step 1816 , the process proceeds to step 1817 at which it is determined whether NB is greater than macMaxCSMABackoffs. If NB is not greater than macMaxCSMABackoffs, then the process returns to step 1813 . If NB is greater than macMaxCSMABackoffs, then the process ends in failure.
[0137] If the channel is determined to not be idle at step 1815 , then the process proceeds to step 1818 at which CW may be set such that CW=CW-1. After the CW is set, the process proceeds to step 1819 at which it is determined whether CW=0. If CW is determined to not equal 0, then the process returns to step 1814 . However, if CW is determined to equal 0, then the process ends in success.
[0138] Referring to FIGS. 18A and 18B , if at step 1801 it is determined that the CSMA-CA operation is not slotted, then the process proceeds to step 1802 . At step 1802 , the NB may be set such that NB=0 and ME may be set such that BE=macMinBe. Thereafter, the process proceeds to step 1803 at which a delay is performed. As an example, the delay may be for a number of unit backoff periods corresponding to random(2 BE -1). Thereafter, the process proceeds to step 1804 at which a CCA is performed. After performing the CCA, the process proceeds to step 1805 at which it is determined whether the channel is idle. If the channel is determined to be idle at step 1805 , then the process proceeds to step 1806 at which NB may be set such that NB=NB+2 and BE may be set such that BE=min(BE+2, macMaxBE). Thereafter, the process proceeds to step 1807 at which it is determined whether NB is greater than macMaxCSMABackoffs. If it is determined that NB is not greater than macMaxCSMABackoffs, then the process returns to step 1803 . If NB is determined to be greater than macMaxCSMABackoffs, then the process ends in failure.
[0139] Conversely, if at step 1805 it is determined that the channel is idle, then the process ends in success.
[0140] According to exemplary embodiments of the present invention, even in the same CAZ, differentiated access may be performed based on the queue information exchanged in an MBP in advance, taking into account inter-device QoS.
[0141] FIG. 19 shows a process of performing load control using an MBP in a coordinator according to an exemplary embodiment of the present invention.
[0142] In step 1900 , the coordinator 100 determines whether contention for data transmission in a CAP due to backlogged traffic has increased. If the contention has increased, the coordinator 100 proceeds to step 1902 . Otherwise, the controller 100 performs common data transmission in step 1901 .
[0143] In step 1902 , the controller 100 generates a beacon frame including MBP information and broadcasts it to devices.
[0144] The coordinator 100 determines in step 1903 whether a queue information packet for load control is received from each device without error in an MBP. If the queue information packet is received without error, the coordinator 100 proceeds to step 1905 . Otherwise, the coordinator 100 sends no response (or ACK) to each device in step 1904 .
[0145] In step 1905 , the coordinator 100 sends a response to the queue information packet received without error, to each device.
[0146] FIG. 20 shows a process of performing load control using an MBP in a device according to an exemplary embodiment of the present invention.
[0147] In step 2000 , the device 110 receives a beacon frame including MBP information from the coordinator 100 .
[0148] In step 2001 , the device 110 finds the required amount of resources needed for packet transmission based on the received MBP information, and then determines the number of CAZs depending on the found required amount of resources.
[0149] In step 2002 , the device 110 determines the number of MBZs, which corresponds to the determined number of CAZs. The number of MBZs is equal to the number of CAZs.
[0150] In step 2003 , the device 110 transmits a queue information packet for load control to the coordinator 100 in an MBZ corresponding to the time point selected from among the determined number of MBZs.
[0151] In step 2004 , the device 110 determines a CAP type depending on whether its transmission of a queue information packet is successful and whether packet transmissions by other devices are successful. For example, the device 110 may determine any one of an Exclusive CAP, a Normal CAP, and a Background CAP depending on whether its transmission of a queue information packet is successful.
[0152] In step 2005 , the device 110 performs a data transmission/reception operation using the determined CAP.
[0153] For example, upon receiving a response message to the queue information packet from the coordinator 100 , the device 110 determines a type of CAP as an Exclusive CAP, determining that its transmission of a queue information packet is successful, and performs data transmission using the determined Exclusive CAP.
[0154] If transmissions of a queue information packet by other devices are failed, the device 110 determines a type of CAP as a Normal CAP, and performs data transmission using the determined Normal CAP.
[0155] If transmissions of a queue information packet in an MBP are all failed, the device 110 determines a type of CAP as a Background CAP, and performs data transmission using the determined Background CAP.
[0156] As is apparent from the foregoing description, in operations of a coordinator and a device, devices participating in packet transmission/reception may receive the packets which are transmitted and received in an MBZ. For example, if another device receives the packet whose address is designated as an address of a specific device, such as unicast, in an MBZ, then the device may demodulate the packet regardless of its original destination so that the packet transmitted/received between the coordinator and the specific device may be delivered to other devices, making it possible to determine whether the packet transmission is successful. In addition, as a destination address of a queue information packet or a response packet is set as a broadcast address, the packet may be delivered not only to the device but also to the coordinator, making it possible to determine whether the packet transmission is successful. In this case, the coordinator broadcasts a response to the received packet.
[0157] In this manner, exemplary embodiments of the present invention may enable efficient resource access by performing load control in a distributed manner, for data transmission/reception, thus contributing to a reduction in access delay and power consumption and enabling appropriate QoS control.
[0158] While the invention has been shown and described with reference to certain exemplary embodiments thereof, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents. | A method and a system for operating a Mutual Broadcast Period (MBP) and Contention Access Period (CAP) for load control are provided. The proposed system and method is suitable for a short-range communication environment such as communication environment in or around the human body, and is for a mesh network communication environment in which one piconet is formed around the human body or a plurality of devices are connected. When signals carrying biometric information are periodically received from a plurality of sensor devices for medical purposes, the system and method may achieve efficient resource access by performing load control in a distributed manner, contributing to a reduction in access delay and power consumption and enabling appropriate QoS control. | 50,026 |
FIELD OF THE INVENTION
[0001] This application generally relates to systems and methods for authenticating a bulk quantity of a consumable product with a corresponding product. More specifically, the invention associates a bulk quantity of the consumable product with a product parameter such as a consumption rate of the consumable product within the corresponding product; provides and authorizes a key and/or reader with the bulk quantity and consumption rate data to a specific corresponding product wherein the bulk quantity and consumption rate data are correlated to a maximum consumption quantity value; monitoring consumption of the consumable product within the corresponding product until the maximum consumption quantity value is reached; and providing an event output to the corresponding product when the maximum consumption quantity value is realized.
BACKGROUND OF THE INVENTION
[0002] In today's competitive marketplace, the costs for companies to create, maintain, and grow new markets and market share is becoming increasingly expensive. Providing low cost systems of assuring the company's investment is protected by newcomers into the market place is increasing in demand. Previous systems of differentiating the authenticity of a product have generally focused on individual pieces. That is, if a manufacturer wants to ensure that a specific refill or consumable product (eg. a printer toner cartridge or a soap refill) is configured to specific equipment, that is the primary or corresponding product (eg. a printer or soap dispenser), each refill product will be individually provided with the authentication system that allows the refill product to be used with the primary product.
[0003] In cases where the individual consumable pieces are inexpensive or that have a physical shape that does not readily permit the inclusion of authentication systems, present authentication techniques are difficult to implement or are too expensive to justify the costs. For example, if the refill product is only worth a few pennies, the cost of incorporating an authentication system that may cost at least a few pennies to incorporate with the refill product cannot usually be justified.
[0004] Furthermore, for these types of products, as with other products that are readily marked, there has also been a need to enhance brand protection, to monitor and maintain shelf-life requirements and best-before dates, limit the life of a material, ensure non-compatible products are not used inappropriately for safety considerations, as well as for distribution control and prevention of cross selling into markets.
[0005] As described in co-pending application PCT/CA2011/001008, authentication technologies having electronic keying that utilize special optical coatings are effective and inexpensive methods of being able to differentiate between authentic products and counterfeit products on an individual basis. As described in PCT '008, individual products can be linked or keyed to a specific dispensing product using inexpensive LED emitters/receivers and special optical coatings. However, the PCT '008 technology generally requires that the two products are in close proximity to one another in order for the keying to be enabled and can thus be limited by a number of factors including the geometric limitations of the consumable and corresponding products.
[0006] In other words, and by way of example, with regards to bulk products, there has been a need for a system that enables the consumption of bulk products to be monitored without the need for marking each specific item. For example, it is more difficult and potentially expensive to mark individual hot drink stir sticks that may be used with a commercial stir stick dispenser. However, as is known, stir sticks are generally packaged and shipped in larger containers/boxes that may contain several hundred dozen individual sticks. As such, specifically keying individual stir sticks to a dispenser is difficult or impractical.
[0007] Thus, there is a need for an authentication system and methodology that is capable of and that is inexpensive enough to authenticate a wider range of products including odd-shaped and inexpensive products.
[0008] Further still, there has been a need for product authentication systems that can be readily retro-fit to existing equipment, such that existing equipment can be effective in ensuring that properly authenticated consumable products are used within the existing equipment without the need for extensive modifications to the existing equipment.
[0009] Further still, there has been a need for systems that can effectively monitor the consumption of product across a number of different pieces of equipment.
SUMMARY OF THE INVENTION
[0010] In accordance with the invention, there is provided a method of authenticating a bulk quantity of a consumable product with a corresponding product that utilizes the consumable product comprising the steps of: (a) associating a bulk quantity of the consumable product with a consumption parameter of the consumable product within the corresponding product; (b) authorizing a key with the bulk quantity and consumption parameter from step a) to a specific corresponding product wherein the bulk quantity and consumption parameter are correlated to a quantity value; (c) monitoring consumption of the consumable product within the corresponding product until the quantity value is reached; and (d) providing an event output to the corresponding product when the quantity value is realized.
[0011] In various embodiments, the event output is an audio and/or visual signal to an end-user; and/or the quantity value is any one of or a combination of total volume, total mass or time.
[0012] In another embodiment, the method further includes the step of altering the operation of the corresponding product when the quantity value is reached which may include increasing the amount of material being dispensed when the quantity value is reached, decreasing the amount of material being dispensed when the quantity value is reached or stopping the amount of material being dispensed when the quantity value is reached.
[0013] In various embodiments, the key contains data including any one of or a combination of product serial number, jurisdictional data, shelf-life or quantity data.
[0014] In another aspect, the invention provides a system for authenticating a bulk quantity of a consumable product with a corresponding product that utilizes the consumable product comprising: a key and reader for operative connection to the corresponding product, the key containing information relating to a consumption parameter of the consumable product and the reader having a controller for monitoring the consumption parameter of the consumable product within the corresponding product as the consumable product is being consumed relative a to quantity value; the controller monitoring consumption of the consumable product within the corresponding product and determining when the quantity value is reached, the controller providing an event output when the quantity value is reached to an output event circuit operatively connected to the controller.
[0015] In further embodiments, the output event circuit includes an audio and/or visual circuit for providing an audio or visual signal to an end-user.
[0016] In other embodiments, the quantity value is any one of or a combination of total volume, total mass or time.
[0017] In other embodiments, the controller includes means for altering the operation of the corresponding product when the quantity value is reached which may include increasing the amount of material being dispensed when the quantity value is reached, decreasing the amount of material being dispensed when the quantity value is reached or stopping the amount of material being dispensed when the quantity value is reached. The key may also contain data including any one of or a combination of product serial number, jurisdictional data, shelf-life or quantity data.
[0018] In yet another aspect, the invention provides a retro-fit system for detecting consumption of a consumable product with a corresponding product that utilizes the consumable product, the system for retro-fit connection to the corresponding product, the system comprising: a body for attachment to the corresponding product, the body operatively containing: a controller operatively connected to a power supply; a reader operatively connected to the controller, the reader for operative connection with a key containing quantity information relating to the consumable product; a use detector operatively connected to the controller for detecting operation events of the corresponding product; wherein the controller includes a counter for counting operation events and includes means for calculating total consumption and comparing total consumption to the quantity information, the controller having means to activate an alarm system operatively connected to the controller in the event that total consumption exceeds the quantity information.
[0019] In one embodiment, the system includes a solar cell operatively connected to the controller and power supply for providing solar energy to the power supply.
[0020] In further embodiments, the system may also include a communication interface operatively connected to the controller for communicating any one of or a combination of total consumption information or alarm events to a computer network.
[0021] In another embodiment, the system includes a communication interface operatively connected to the controller for communicating any one of or a combination of total consumption information or alarm events to an adjacent retrofit system.
[0022] In another aspect, the invention includes two or more retro-fit systems, each for detecting consumption of a consumable product with a corresponding product and each operatively connected to separate corresponding products and wherein each retro-fit system includes means for communicating consumption data between each retro-fit system. In these embodiments, each controller may calculate total consumption based on consumption information received from each retro-fit system for determining if an alarm condition exists. Key information between each controller can also be exchanged to provide authorization to multiple retro-fit systems within a network.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] The invention is described with reference to the accompanying figures in which:
[0024] FIG. 1 is a schematic diagram of a key and reader system on a corresponding product (eg. dispenser) and a corresponding bulk product in accordance with one embodiment of the invention;
[0025] FIG. 2 is a schematic diagram of a retro-fit kit for use with a corresponding product (eg. a dispenser) in accordance with one embodiment of the invention; and,
[0026] FIG. 3 is a flow chart illustrating typical logic utilized in monitoring the consumption of a consumable product in accordance with one embodiment of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0027] With reference to the figures, various embodiments of systems and methods for authorizing bulk products with specific dispensing apparatus are described. In addition, systems and methods of retro-fitting authorization technology to existing equipment are described.
[0028] In the context of this invention, bulk or consumable products generally mean products that may be any one of or a number of difficult to mark, relatively inexpensive and/or that are normally shipped in larger containers with a number of smaller packages/containers within the bulk shipment. These products are generally used with a corresponding product that will either dispense or use the consumable product and which collectively constitute a product pair. Examples of such product pairs include but are not limited to food product dispensers (eg. breakfast cereal, condiment and milk dispensers), bulk chemical dispensers (eg. soap, window cleaner, surface sanitizer dispensers), and product dispensers (eg. hot drink stir stick dispensers).
[0029] As shown in FIG. 1 , generally the invention provides a key 12 that is associated with a bulk product or container 22 and that is coded to contain information about a consumable product 14 that may be within a smaller package within a bulk container 22 . The key is interfaced with a reader 16 within a dispensing apparatus 18 that can read and obtain data from the key. The key contains information about the consumable product such that the dispensing apparatus 18 (dispenser) will operate in an unrestricted mode only if the key is interfaced (eg. within a slot or opening 20 ) with the dispenser and is otherwise being operated consistently within the authorized parameters of the consumable product.
[0030] For example, a restaurant operator may provide a breakfast cereal dispenser 18 into which fixed volumes/weights of bagged breakfast cereal are inserted. An end user typically uses the dispenser by approaching the dispenser and turning a knob in order to dispense a fixed volume of breakfast cereal. During normal operation, restaurant staff will periodically monitor the level of breakfast cereal in the dispenser and when the levels become low, re-fill the cereal dispenser with a pre-packaged volume of breakfast cereal from a store room.
[0031] As shown in FIG. 1 , the cereal for each re-fill may be contained in a plastic bag that was purchased as a bulk shipment 22 of breakfast cereal. For the purposes of illustration, the bulk shipment may contain 10 bags of breakfast cereal (numbered 1 to 10). In this case, after retrieving a bag of breakfast cereal from the bulk shipment box, the restaurant staff will simply open a new bag of cereal and pour it into the dispenser. As can be appreciated, as the plastic bag is thrown away immediately after emptying, marking the individual plastic bag with specific coded information will be of little use for the purposes of keying as the bag itself is not interfaced with the cereal dispenser. Moreover, busy restaurant staff cannot be concerned with ensuring that proper keying is occurring every time they fill up a breakfast cereal dispenser.
[0032] However, and in accordance with the invention, replacing a key in the dispenser each time a new bulk shipment box is opened can provide an effective system for ensuring that the authorized breakfast cereal is used in the dispenser and involvement with end-users is minimal. In our example, the bulk shipment box 22 is provided with a key 12 that can be interfaced with the dispenser 18 and contain information that permits operation of the dispenser for a specific period of time and/or to dispense a specific quantity of product. Upon the expiry of the specific parameters of the key (primarily a maximum quantity), the dispenser will prevent operation of the dispenser and/or signal that new product is required. For example, the key may be coded to permit the equivalent of 10 bags of cereal to be dispensed from the dispenser. Thus, after the assumed volume/weight of 10 bags of cereal (with appropriate allowances), the dispenser may be shut-down. If the dispenser is shut-down, this will provide a clear signal to the end-user (i.e. restaurant staff) that a new key must be interfaced with the dispenser.
[0033] Alternatively, the dispenser may simply signal through a signal system 24 that the key has expired by a visual 24 a and/or audio 24 b signal that will continue until a new key is inserted. In this case, the dispenser may not be shut-down upon the expiry of the key where, in this embodiment it would be assumed that the warning signal is sufficient reminder to the end-users that an authorized product key must be interfaced with the dispenser to ensure that authorized product is used with the dispenser.
[0034] While a system only incorporating a signal system that does not completely shut-down a dispenser will not absolutely prevent the use of unauthorized product in the dispenser, as a user could add cereal to the dispenser that has been obtained from a non-authorized manufacturer, at the very least the warning system will substantially reduce the use of unauthorized products as the warning system may be sufficiently disruptive to the operation of the dispenser that it will motivate the end-user to obtain a new key.
[0035] In various embodiments, the packaging of the bulk product may also be configured to ensure that opening the bulk product ensures that the first product out of the box is matched with a new key to ensure that the new key is paired with the dispenser when the first product is used. In our example, the key 12 is attached to bag 1 and would be clearly marked to ensure it is the first product to be used. In one embodiment, each product is marked with a number to advise users the order in which the product should be utilized. In one embodiment, after consumption of a certain percentage of the bulk product, a visual reminder 8 a (eg. a card) may also be provided to remind a user to order new bulk product although this can also be achieved electronically through the system as described below.
[0036] As can be understood, the above technology can be applied to a wide array of dispenser/product pairs such as laundry machines/soap, dishwashers/soap, paper dispensers/paper, hand sanitizers/sanitizer, waxing machines/wax, milk dispensers/milk as well as many other products.
[0037] In various embodiments, the key can be configured with a variety of data. As noted above, this can be an authorized weight/volume of product and/or a time parameter. Time-based authorizations can be utilized to ensure that shelf life/expiry dates are respected. That is, in the case of a product such as a milk dispenser/milk container product pair, the milk dispenser may monitor both the weight/volume of milk being dispensed as well as the shelf-life date. In this example, the bulk quantity of milk may have a code that indicates that 25 liters of milk can be dispensed as well as a code indicating that the shelf-life of the product is 7 days. Upon the expiry of either parameter, the dispenser may then enter an unauthorized condition where one or more alarms are presented to the user.
[0038] In addition, authorization to ensure distribution control can also be implemented. As an example, a manufacturer may wish to prevent a distributor in one jurisdiction from selling into another jurisdiction. That is, a first distributor may be authorized by a manufacturer to sell product in a first jurisdiction but not be authorized to sell product into a second jurisdiction due to contractual obligations with a second distributor in a second jurisdiction. However, in the absence of authorization technology that does not individually mark each end-product, it is effectively impossible to enforce jurisdictional boundaries with each distributor. With the subject system, an appropriate jurisdictional code can be attached to each bulk shipment to ensure that a product can effectively only be paired to a corresponding product of the product pair in an authorized jurisdiction.
[0039] Importantly, the subject system also allows the cost of authentication between product pairs to be reduced as many of the disadvantages of specific dispenser/product pairing can be obviated. For example, in many product pairs, there is substantial additional cost associated with incorporating authentication technology within the specific geometries of products. That is, in order to ensure that a dispenser using a specific refill cartridge can authenticate in a manner that is reliable and/or possible, significant geometric limitations of the physical dimensions of the products may have to be overcome in order to effectively provide product pair linking.
[0040] In the subject system, the key system may be substantially simplified in terms of its geometric shape and/or size. For example, the key could be a simple, thin paper or plastic card that contains the authorization information. Similarly, the reader may be a simple slot that receives the key. Importantly, by simplifying the geometry between the key and reader in such a way that it is not actually on the product packaging or otherwise incorporated into the consumable product, allows the key and reader to be located in favorable locations on the dispenser. For example, the reader can likely be configured to a position of the dispenser where there is naturally dead volume within the dispenser and thus may be more readily incorporated into existing dispenser designs.
[0041] Furthermore, the key and reader may also be established as a retro-fit kit for certain products, where an existing dispenser can be retrofit to include bulk authorization functionality. As shown in FIG. 2 , a retro-fit kit 50 may include a reader 16 for receiving a key 12 within a slot 20 and associated authorization electronics contained within a compact package. Typically, the package will include means to interrupt power 12 f to the dispenser and/or provide a visual or audio warning through an output system 24 a, 24 b to an end-user. While a specific retro-fit kit may be designed for a specific dispenser, based on the specific shape and available volumes within the dispenser, many different dispensers may be able to utilize the same kit to achieve the desired functionality given that many dispensers will have at least a minimum available volume for configuration of the kit.
[0042] In one embodiment, the kit may be externally configured to the dispenser and only utilize a visual or audio warning system 24 a, 24 b that does not require wiring to the dispenser. For example, the retro-fit kit may be a box 40 that is permanently or semi-permanently attached to the exterior of the dispenser. In this case, a manufacturer with a line of dispensers may retroactively connect a retro-fit authentication system to the exterior of the dispenser by an appropriate attachment system such as screws, bolts, two-side adhesive tape and/or glue. The manner in which the authentication system is attached may be sufficiently secure that attempts to remove the retro-fit kit will result in damage to the dispenser, although this may not be required for certain installations. The box will contain an appropriate controller 16 a and reader 20 to interface with a key 12 as described above.
[0043] In one embodiment, the retro-fit kit will include a rechargeable battery 12 b that is configured to a solar cell 12 c for charging the battery. In this embodiment, which will be particularly useful for dispensers that are deployed in lighted locations, the solar cell will ensure that the battery remains charged such that, the warning system will be able to provide its warning for a substantial period of time, for example, for at least several weeks, and potentially indefinitely in the event that the solar power cell has a sufficient power rating to provide continuous power. In this case, the controller 12 a may also be programmed to provide an alarm sequence that is balanced to the availability of power within the battery. In the case of an audio alarm, the alarm needs only to be sufficiently loud in order to be noticeable but not so loud as to be uncomfortable. While a visual alarm may also be implemented, on its own this may be less preferred.
[0044] In those embodiments where the retro-fit kit is simply configured to the exterior of the dispenser and does not directly interface with the internal dispensing mechanisms of the dispenser, the detection of operation events such as rates of consumption can be implemented for certain types of dispensers. For example, for those dispensers that include a motor (or systems that produce identifiable physical effects) that is actuated each time a dispenser operation occurs, the retro-fit kit may include a vibration sensor 12 d (or similar device) that would detect the movement of the motor or related or similar components. Thus, the retro-fit kit could detect and monitor the number of dispense operations to calculate when an authorization key is no longer valid. As an example, in the case of a soap dispenser, the soap dispenser may include a motor and valve mechanism to dispense a fixed volume of soap with each actuation. In this case, after an authorization key has been inserted into the retro-fit kit box 40 , the retro-fit kit controller 16 a would simply count the number of dispenses by detecting motor vibration each time the motor is turned on. Thus, based on the knowledge of the volume per dispense, the number of valid dispenses can be calculated. After reaching the threshold number of dispenses, the alarm system 24 a, 24 b would be actuated. Other types of sensors may also be provided including strain gauges, optical and/or ultrasonic sensors.
[0045] This system may also be used as a retro-fit notification system for advising personnel that a consumable product is nearing exhaustion and will need replacement. In this aspect of the invention, the retro-fit notification system may be implemented without the bulk authentication concepts described above and may simply be a means of advising when an individual quantity of a consumable product is nearing exhaustion. In this case, for example when 80% of the product has been consumed, the alarm system may actuate at a first level, perhaps flashing a small LED light at a 5 second interval. When 90% of the product has been consumed, the alarm system may flash the LED light at a 2 second interval. When 95% of the product has been consumed, the alarm system may add an audio alarm at a 10 second interval. Thus, when service personnel are in the proximity of the dispenser, they can make a determination of the level of product remaining in the dispenser. As understood by those skilled in the art, any number of alarm conditions may be designed and incorporated.
[0046] In addition to motor vibration sensors, other means of detecting the number of actuations may be used. For example, the retro-fit kit may include an infra-red or ultrasonic sensor 12 e that detects the presence of an end-user and base the consumption calculation on the number of times an end-user is detected.
[0047] The ability to retro-fit an authentication system to product pairs may be particularly beneficial within certain businesses or chains of business where factors such as product quality are essential components of a business. For example, in the case of franchises, it is often very important for franchisers to control the supply of product to their franchisees to ensure that customers receive product of consistent quality across multiple locations and over time. Very often, the good will of the franchise business will depend on the consistency of the product that is delivered to customers. While a franchise contract may require that product be purchased from authorized sources, it may be difficult to ensure that the actual product being sold was in fact purchased from an authorized source.
[0048] For example, while a national chain of coffee shops may require that only coffee of a specific brand is used in the coffee brewing machines of the franchise, a franchisee may choose to utilize another (possibly less expensive) source of coffee in the coffee machine. However, if a retro-fit authorization kit is configured to a coffee machine, the retro-fit kit may be able to count the number of brew cycles the coffee machine goes through as a measurement of the consumption of coffee and thereafter activate the alarm system if an alarm condition is detected.
[0049] In situations where multiple dispensing machines may be utilizing bulk product from a single bulk shipment (as shown in FIG. 1 ), different dispensers may have to share information to ensure that consumption rates are being properly monitored. Accordingly, a retro-fit circuit may also include wireless functionality in the form of a communication interface 12 g that collectively enables adjacent machines to monitor the total consumption rates across more than one machine. In addition, if consumable product is being received from a single bulk packaging source, the controller in each adjacent retro-fit unit may share key information across a network such that only a single key is required to provide authorization to multiple retro-fit units.
[0050] Wireless technology may also be utilized as a reminder to users when to initiate the re-ordering of product. For example, a coffee machine that has calculated that 50 pots of coffee have been brewed since the authentication key was interfaced with the coffee machine, may initiate a network event that triggers an email, SMS, or similar alert being sent to an owner to order additional coffee. Communicative technology, including both wireless and wired technology, may also be utilized to inform of non-compliance events. For example, if a franchisee is utilizing a non-authorized coffee bean, an alert can be generated by a communication interface 12 g and sent to the franchiser to inform of the non-compliance event.
[0051] In various embodiments, the keying system will also only be accessible to higher level users (eg. restaurant staff) as opposed to final end-users (eg. customers). For example, in our bulk cereal example, restaurant staff (higher level user) may have access to the authentication key 12 only when a dispenser cabinet is opened with a regular lock key so as to minimize the risk of tampering by the end-user (restaurant customer).
[0052] For the retro-fit kit embodiment, similarly a lock or cover 30 may be provided that requires a regular lock key to open in order to prevent end-user access to the key 12 .
Authentication
[0053] Authentication can occur using a variety of authentication methodologies and systems including the authentication systems as described in U.S. Pat. No. 7,793,839 and co-pending application PCT/CA2011/001008 incorporated herein by reference. Other authentication systems could include bar codes, magnetic stripe, smart cards etc. Codes will typically include serial numbers and product specific codes that represent authorized weights/volumes/times etc. Importantly, the key and reader combinations may utilize read-only or read/write technologies depending on the specific product pair and requirements of the manufacturers/distributors and/or end users. in the read/write scenario, after the expiry of the product specific code (i.e. the weight/volume/time code), the code on the key may be irreversibly altered to prevent future reading of the code by any reader.
[0054] FIG. 3 is a flow chart depicting a typical process by which electronics in the corresponding product (eg. a dispenser) would monitor consumption of a consumable product. While an authorization key is not present 501 the system would be in an unauthorized mode and operation of the dispenser would be in a corresponding condition (eg. Increasing, decreasing the dispensed quantity of product and/or preventing operation and/or providing a visual/audio signal). If the authorization key is present 502 , data from the key would be read 503 and determined if the product was authorized with the dispenser 504 . If the product was authorized, a dispense counter would be set to a value N 505 and would decrease the counter by one with each use 506 . The dispenser would continue to operate while the counter was greater than zero 507 . For any condition that was interpreted as unauthorized, the system would return to idle 501 .
[0055] Although the present invention has been described and illustrated with respect to preferred embodiments and preferred uses thereof, it is not to be so limited since modifications and changes can be made therein which are within the full, intended scope of the invention as understood by those skilled in the art. | This application generally relates to systems and methods for authenticating a bulk quantity of a consumable product with a corresponding product. More specifically, the invention associates a bulk quantity of the consumable product with a product parameter such as a consumption rate of the consumable product within the corresponding product; provides and authorizes a key and/or reader with the bulk quantity and consumption rate data to a specific corresponding product wherein the bulk quantity and consumption rate data are correlated to a maximum consumption quantity value; monitoring consumption of the consumable product within the corresponding product until the maximum consumption quantity value is reached; and providing an event output to the corresponding product when the maximum consumption quantity value is realized. | 32,822 |
FIELD OF THE INVENTION
[0001] The present invention involves a wound dressing comprising chemically modified chitosan fiber or unmodified chitosan fiber, and chemically modified cellulose fiber, providing clinical benefits in bacteriostatic and fluid absorption. The wound dressing is useful in treatment of chronic wounds, such as venous stasis ulcers, pressure ulcers, diabetic foot ulcers and other chronic ulcers.
BACKGROUND OF THE INVENTION
[0002] It is well known that nurses are facing some challenges when selecting the right wound dressing for the management of chronic wounds. In addition to managing the wound exudates, they also need to consider providing a good healing environment for the wound. This good healing environment includes inhibiting the growth of microorganisms.
[0003] Chitosan has a bacteriostatic property by the existence of the amino groups in the molecule of chitosan. The positive charge of a chitosan molecule neutralizes the negative charge of cell membrane of bacteria inhibiting the growth of the bacteria. On the other hand, small molecules of chitosan penetrate through the bacterial cell membrane into the cell nucleus to inhibit enzyme formation. This can be observed in the general inhibition test. When the chitosan wound dressing is placed onto a Petri-dish for 24 hrs that has been covered with bacteria, a clear or less cloudy can be seen underneath the wound dressing whilst all other areas of the bottom of the Petri-dish displayed a cloudy appearance. This means that the area underneath the chitosan wound dressing has less bacterial growth than other areas which has not been covered by the chitosan dressing. This demonstrates that chitosan has a bacteriostatic property, which can be used to treat infected wounds.
[0004] Generally speaking, silver wound dressings also have bacteriostatic properties. However, a wound dressing containing silver which may be cytotoxic.
[0005] EP0690344 and U.S. Pat. No. 3,589,364 disclose an absorptive wound dressing manufactured by carboxymethyl cellulose fibers. WO2010/061225 discloses a method of preparing modified cellulose fiber by forming a water insoluble alkyl sulfonate cellulose fiber to improve its absorbency. According to the above patents, high absorbency can be obtained when the cellulose fibers are chemically modified. However this type of dressing does not have bacteriostatic properties.
[0006] Alginate dressings are also used in the management of chronic wounds. However alginates do not have bacteriostatic properties, its absorbency is also lower than that of chemically modified cellulose fibers.
[0007] EP0740554 and U.S. Pat. No. 6,471,982 disclose a fibrous wound dressing prepared by blending a gelling fiber such as an alginate fiber and a non-gelling fiber such as cellulose fiber. This blending method may reduce the cost of the product.
[0008] U.S. Pat. No. 7,385,101 discloses a wound dressing composed of a silver nylon fiber and an absorptive fiber. This dressing is used in managing the infected wounds.
[0009] U.S. Pat. No. 5,836,970 describes a wound dressing composed of chitosan fiber and alginate fiber. This patent disclosed the bacteriostatic and haemostatic properties of chitosan fiber and the absorbency of alginate fiber.
[0010] U.S. Pat. No. 6,458,460, EP0927013 and CN1303355 describe a wound dressing containing two gelling fibers, one is carboxymethyl cellulose fiber and the other one is alginate fiber. The mixture of these two fibers helps to improve the dressing absorbency, but does not have bacteriostatic property.
[0011] EP1318842 disclosed a wound dressing composing a silver fiber and a non-silver fiber. This wound dressing possesses antibacterial function as well as absorbency. This type of dressing generally is cytotoxic.
[0012] CN1313416 disclosed a method of blending cotton fibers and chitosan fibers. Although the purpose of this invention was not for wound care, it also disclosed that the product prepared by this method has antibacterial function.
[0013] Therefore it become a clinical need to develop a wound dressing that is very absorbent to wound fluid but can also provide some bacteriostatic functions.
SUMMARY OF THE INVENTION
[0014] The present invention involves a wound dressing characterized in that the wound dressing comprises of chitosan fibers and chemically modified cellulose fibers. The chitosan fiber can be chemically modified or unmodified fiber. Particularly, the invention involves a wound dressing prepared by blending chitosan fibers and chemically modified cellulose fibers to obtain a fabric. Because of bacteriostatic property of the chitosan fiber and the high absorption capacity of the chemically modified cellulose, the dressing of the present invention can provide an ideal healing environment of bacteriostatic properties and fluid absorption to the chronic wound. Furthermore, the ratio of the chitosan fiber to chemically modified cellulose can be adjusted to suit the need of each type of the wound. For example for a wound that has a large amount of fluid but has not yet developed the wound infection, a dressing containing a small percentage of chitosan fiber is more suitable, as the small amount of chitosan fiber may be sufficient to prevent the wound from infection whilst the majority of the dressing is made of chemically modified cellulose which can provide the fluid absorption capacity needed for this type of the wound exudate. For example 30% of chitosan fiber and 70% of chemically modified cellulose fiber. However for the wound type that has already got infection, the dressing with more chitosan fiber is best suited, such as 70% of chitosan fiber and 30% of chemically modified cellulose fiber.
[0015] The present invention also relates to the application of the said wound dressing in the management of chronic wounds
[0016] Particularly, the invention involves a wound dressing wherein the wound dressing is composed of 5-95% w/w of chitosan fibers, 95-5% w/w chemically modified cellulose fibers, preferably 10-90% w/w of chitosan fibers, 90-10% w/w chemically modified cellulose fibers. All fiber percentage is based on the total weight of chitosan fiber and the chemically modified cellulose fibers. The wound dressing in the present invention is manufactured by blending of 5-95% w/w of chitosan fibers and 95-5% w/w chemically modified cellulose fibers. The blending is achieved during the carding and nonwoven process, i.e. the two fibers are weighed separately and blended together during or before the fiber opening stage, then carded together to form a nonwoven fabric made of a homogeneous mix of two fibers.
[0017] This invention also involves a method of manufacturing the said wound dressing by blending of chemically modified or unmodified chitosan fibers and chemically modified cellulose fibers through a nonwoven process, followed by slitting, cutting, packaging and sterilisation.
[0018] The wound dressing in the present invention can be used in the management of chronic wounds, such as venous stasis ulcers, pressure ulcers, diabetic foot ulcers and other chronic ulcers.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] FIG. 1 shows the photo of the area underneath of the dressing prepared by blending 5% of chitosan fiber and 95% of chemically modified cellulose fiber at 1 day against Staphylococcus aureus;
[0020] FIG. 2 shows the photo of the area underneath of the dressing prepared by blending 95% of acylated chitosan fiber and 5% of chemically modified cellulose fiber at 1 day against Escherichia coli;
[0021] FIG. 3 shows the photo of the area underneath of the dressing prepared by blending 50% of acylated chitosan fiber and 50% of chemically modified cellulose fiber at 1 day against Staphylococcus aureus; and
[0022] FIG. 4 shows the device that was used in the wet strength tensile testing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0023] In an example of the present invention, chitosan fibers and chemically modified cellulose fibers were prepared respectively by their manufacturing process. Chitosan fiber can be prepared by first dissolving the chitosan powder in an acetic acid aqueous solution, then extruding the mixed chitosan solution (dope) into sodium hydroxide solution for precipitation. This is followed by washing, stretching, drying, cutting into staple fiber. The degree of deacetylation of the chitosan fiber is 50% or above, preferably 70% or above. Chemically modified chitosan fiber is prepared by reacting the chitosan fiber with certain chemicals so that the chitosan fiber becomes more absorbent or gelling. Typical examples of this kind of treatment are carboxymethylation or acylation treatments.
[0024] The chemically modified chitosan fiber used in the present invention is acylated chitosan fiber or carboxymethyl chitosan fiber. Carboxymethyl chitosan fiber is prepared by reacting the chitosan fiber with halogenated acetic acid. The acylated chitosan fiber is obtained by reacting the chitosan fiber with succinic anhydride. These chemical treatments make the chitosan fiber absorbent and gelling.
[0025] The chemically modified cellulose fiber used in the present invention is carboxymethyl cellulose fiber, preferably the carboxymethylated solvent spun cellulose fiber. Or the chemically modified cellulose fiber used in the present invention is a water insoluble cellulose alkyl sulfonate fiber. The chemically modified cellulose fiber is prepared by reacting standard cellulose fiber or solvent spun cellulose fiber (Lyocell) with certain chemicals for increased absorption capacity or gelling property. The preferred chemically modified cellulose fiber is carboxymethyl cellulose fiber or water insoluble cellulose alkyl sulfonate fiber.
[0026] The unmodified chitosan fiber has generally an absorbency to Solution A (a solution containing 8.298 g sodium chloride and 0.368 g calcium chloride dihydrate per liter) of 100% or 200%. The chemically modified chitosan fiber or cellulose fiber has an absorbency to Solution A (a solution containing 8.298 g sodium chloride and 0.368 g calcium chloride dihydrate per liter) of 500% or above, sometimes can be as high as 3000%.
[0027] It is well known that the strength of a wound dressing or a nonwoven material is different in the machine direction compared to the cross machine direction. The machine direction (MD) is the direction that materials move during the manufacturing. The cross machine direction (CD) is the direction 90 degree to the MD. Normally the strength of a nonwoven material in machine direction is lower than that in cross machine direction. Although it is difficult to distinguish machine direction and cross machine direction when the material is cut into square or rectangle dressing, the direction with lower strength can be considered as the MD. Therefore a wound dressing generally has two strengths, one is MD strength and the other is CD strength. The average strength (including average wet strength) is the average of MD and CD strengths. The average wet strength of the wound dressing in the present invention is 0.3 N/cm or above, preferably 0.5 N/cm, more preferably 1.0 N/cm, most preferably 1.8 N/cm or as high as 6.0 N/cm.
[0028] In an example of the present invention, chitosan fibers and chemically modified cellulose fibers are blended before or during the carding process. Usually, the blending process takes place in the fiber opening stage, followed by carding and needling processes. The carding process can further open and blend the two fibers to achieve a homogeneous mix. The typical nonwoven method is needle punching process.
[0029] In another example of the present invention, the chitosan fibers and the chemically modified cellulose fibers may contain surfactant, lubricant or antimicrobial agent. Some of these are process aids, others are for special purposes. For example, to apply Tween 20 onto the fiber surface can improve the process efficiency of the carding and the nonwoven process. For the purpose of enhancing the dressing's ability to kill bacteria and fungi, it will be necessary to add some antimicrobial agents to the fiber such as silver or PHMB.
[0030] In an example of the present invention, the content of chitosan fibers and the chemically modified cellulose fibers can be varied to suit the functional requirement of the wound dressing. The ratio of chitosan fiber can be between 5-95% w/w, calculated on the total weight of both fibers. The ratio of chemically modified cellulose fiber can be 95-5% w/w, calculated on the total weight of both fibers.
[0031] Preferably, the present invention involves a wound dressing composed of 10-90% w/w of chitosan fiber and 90-10% w/w of chemically modified cellulose fiber.
[0032] In the present invention, the fiber's linear density and length are controlled to suit the wound dressing manufacturing process. The linear density of the chitosan fibers and the chemically modified cellulose fibers is between 0.5 dtex to 5 dtex, preferably 2 dtex to 4 dtex. The length of the chitosan fibers and the chemically modified cellulose fibers is between 10 mm to 125 mm.
[0033] The present invention also involves a method of preparing the said wound dressing. The method comprises blending the chitosan fibers and the chemically modified cellulose fibers together during or before the fiber opening stage, then converting the blended fibers into a fabric through a nonwoven process, then cutting, packing and sterilizing. Preferably, the nonwoven process is needle punch process. Other nonwoven process can also be used. For example, one of the said fibers can be converted into a fabric first, and then the other fiber is laminated onto this pre-made fabric by needling or chemical bonding. Although the dressing manufactured by this method is not a homogeneous blend of the two fibers (chitosan fiber and chemically modified cellulose fiber), the dressing can still provide a bacteriostatic environment and high absorbency functions. Another method is to prepare a fabric that contains 100% chitosan fiber (either chemically modified or unmodified, or both) and a fabric that contains 100% chemically modified cellulose fiber first, and then laminate the two fabrics together by needling or chemical bonding.
[0034] According to the shape of different wounds, the wound dressing composed of chitosan fibers and chemically modified cellulose fibers can be cut into a square or rectangular shape to satisfy various applications in wound care.
[0035] The wound dressing in present invention is usually be packed by a known packaging material such as paper/poly, paper/paper, or foil/foil, and then sterilized by gamma irradiation or ETO.
[0036] The present invention can be further illustrated by the following examples.
EXAMPLE 1
[0037] Raw material: Chitosan fiber: linear density 2.0 dtex, fiber length 50 mm. The fiber contains 1% by weight of surfactant (Tween 20). The fiber's absorbency to the solution containing 8.298 g/l of sodium chloride and 0.368 g/l of calcium chloride dehydrate (solution A) is over 110%. Chemically modified cellulose fiber: linear density 1.4 dtex, fiber length 38 mm. The fiber is modified by carboxymethylation reaction. The fiber's absorbency of a solution containing 8.298 g/l of sodium chloride and 0.368 g/l of calcium chloride dehydrate (solution A) is 2200%.
[0038] 100 g of chitosan fiber and 900 g of chemically modified cellulose fiber are blended and opened manually for 5 mins, then fed into a single cylinder card (Cuarnicard). The fibers are further blended into the hopper and the card, then opened and formed into a web. The web is crosslapped and needled into a nonwoven with a base weight of 130 gsm.
[0039] Cut the fabric into 10×10 cm, pack the dressing into pouches then sterilise the dressing by gamma irradiation.
[0040] The dressing has an absorbency of 18.5 g/g, a wet strength in CD direction of 0.45 N/cm, in MD direction of 0.17 N/cm, average 0.3 N/cm.
EXAMPLE 2
[0041] In order to observe the bacteriostatic performance of the wound dressing in Example 1, approximately 0.25 mL of Staphylococcus aureus at a concentration of 10E6-10E7 cfu/mL was evenly coated on a Petri dish. Then the dressing obtained from Example 1 was cut into 2×2 cm and placed into the Petri dish. The Petri dish was then cultured at temperature of 37° C., and observed for the growth of bacteria on the plate. FIG. 1 shows the area underneath the dressing at 1 days.
[0042] From FIG. 1 , it can be seen that the area underneath of the dressing is less cloudy than the rest of the Petri dish, indicating less growth of bacteria underneath of the dressing.
EXAMPLE 3
[0043] Raw material: Acylated Chitosan fiber: linear density 2.0 dtex, fiber length 50 mm. The fiber contains 1% by weight of surfactant (Tween 20). The fiber's absorbency to the solution containing 8.298 g/l of sodium chloride and 0.368 g/l of calcium chloride dehydrate (solution A) is over 1500%. Chemically modified cellulose fiber: linear density 1.7 dtex, fiber length 50 mm. The fiber is modified by carboxymethylation reaction. The fiber's absorbency of the solution containing 8.298 g/l of sodium chloride and 0.368 g/l of calcium chloride dehydrate (solution A) is 1500%.
[0044] Take 400 g of chitosan fiber and submerse the fiber in ethanol solution for 30 minutes. Squeeze the fiber to dry then place the fiber into a 0.1 g/m 1 succinic anhydride solution (894 g of succinic anhydride in 8940 ml of ethanol). Heat to 70° C. for 40 mins. Squeeze the fiber to dry then wash the fiber in an ethanol solution, followed by submersing the fiber in an ethanol solution containing Tween 20. The final steps are drying the fiber to an acceptable moisture content and cutting the fiber to a staple length.
[0045] Take 190 g of the above acylated chitosan and 10 g of chemically modified cellulose fiber, blend and open two fibers manually for 5 mins, then fed the blend into a single cylinder card (Cuarnicard). The fibers are further blended into the hopper and the card, then opened and formed into a web. The web is crosslapped and needled punched into a nonwoven with a base weight of 130 gsm.
[0046] Cut the fabric into 10×10 cm, pack the dressing into pouches then sterilise the dressing by EtO.
[0047] The dressing has an absorbency of 14.6 g/g, a wet strength in CD direction of 2.5 N/cm, in MD direction of 1.1 N/cm, average 1.8 N/cm.
EXAMPLE 4
[0048] In order to observe the bacteriostatic performance of the wound dressing in Example 3, approximately 0.25 mL of E. Coli at a concentration of 10E6-10E7 cfu/mL was evenly coated on a Petri dish. Then the dressing obtained from Example 3 was cut into 2×2 cm and placed into the Petri dish. The Petri dish was then cultured at temperature of 37° C., and observed for the growth of bacteria on the plate. FIG. 2 shows the area underneath the dressing at 1 days.
[0049] From the FIG. 2 , it can be seen that the area underneath of the dressing is less cloudy than the rest of the Petri dish, indicating less growth of bacteria underneath of the dressing.
EXAMPLE 5
[0050] Raw material: Acylated Chitosan fiber: linear density 2.2 dtex, fiber length 75 mm. The fiber's absorbency of the solution containing 8.298 g/l of sodium chloride and 0.368 g/l of calcium chloride dehydrate (solution A) is over 1500%. Chemically modified cellulose fiber: linear density 1.7 dtex, fiber length 50 mm. The fiber is modified by carboxymethylation reaction. The fiber's absorbency of the solution containing 8.298 g/l of sodium chloride and 0.368 g/l of calcium chloride dehydrate (solution A) is 1500%.
[0051] Take 1000 g of the acylated chitosan and 1000 g of carboxymethyl cellulose fiber, blend and open two fibers manually for 5 mins, then fed the blend into a single cylinder card (Cuarnicard). The fibers are further blended into the hopper and the card, then opened and formed into a web. The web is crosslapped and needled punched into a nonwoven with a base weight of 110 gsm.
[0052] Cut the fabric into 10×10 cm, pack the dressing into pouches then sterilise the dressing by EtO.
[0053] The dressing has an absorbency of 14.6 g/g, a wet strength in CD direction of 1.5 N/cm, in MD direction of 0.5 N/cm, average 1.0 N/cm.
EXAMPLE 6
[0054] In order to observe the bacteriostatic performance of the wound dressing in Example 5, approximately 0.25 mL of Staphylococcus aureus at a concentration of 10E6-10E7 cfu/mL was evenly coated on a Petri dish. Then the dressing obtained from Example 5 was cut into 2×2 cm and placed into the Petri dish. The Petri dish was then cultured at temperature of 37° C., and observed for the growth of bacteria on the plate. FIG. 3 shows the area underneath the dressing at 1 days.
[0055] From the FIG. 3 , it can be seen that the area underneath of the dressing is less cloudy than the rest of the Petri dish, indicating less growth of bacteria underneath of the dressing.
EXAMPLE 7
[0056] Raw material: Acylated Chitosan fiber: linear density 2.2 dtex, fiber length 75 mm. The fiber's absorbency of the solution containing 8.298 g/l of sodium chloride and 0.368 g/l of calcium chloride dehydrate (solution A) is over 800%. Chemically modified solvent spun cellulose fiber: linear density 1.4 dtex, fiber length 60 mm. The fiber is modified by carboxymethylation reaction. The fiber's absorbency of the solution containing 8.298 g/l of sodium chloride and 0.368 g/l of calcium chloride dehydrate (solution A) is 3000%.
[0057] Take 1000 g of the acylated chitosan and 1000 g of carboxymethyl cellulose fiber, blend and open two fibers manually for 5 mins, then fed the blend into a single cylinder card (Cuarnicard). The fibers are further blended into the hopper and the card, then opened and formed into a web. The web is crosslapped and needled punched into a nonwoven with a base weight of 160 gsm.
[0058] Cut the fabric into 10×10 cm, pack the dressing into pouches then sterilise the dressing by EtO.
[0059] The dressing has an absorbency of 17.5 g/g, a wet strength in CD direction of 0.9 N/cm, in MD direction of 0.2 N/cm, average 0.55 N/cm.
EXAMPLE 8
[0060] Raw material: Acylated Chitosan fiber: linear density 2.2 dtex, fiber length 50 mm. The fiber's absorbency of the solution containing 8.298 g/l of sodium chloride and 0.368 g/l of calcium chloride dehydrate (solution A) is over 800%. The fiber contains 1% of Tween 20. Carboxymethyl cellulose fiber: linear density 2.2 dtex, fiber length 50 mm. The fiber's surface was sprayed with about 3000 ppm PHMB as an antimicrobial fiber.
[0061] Take 400 g of the acylated chitosan and 100 g of above antimicrobial carboxymethyl cellulose fiber, blend and open two fibers manually for 5 mins, then fed the blend into a single cylinder card (Cuarnicard). The fibers are further blended into the hopper and the card, then opened and formed into a web. The web is crosslapped and needled punched into a nonwoven with a base weight of 100 gsm.
[0062] Cut the fabric into 10×10 cm, pack the dressing into pouches then sterilise the dressing by EtO.
[0063] The dressing has an absorbency of 12 g/g, a wet strength in CD direction of 0.8 N/cm, in MD direction of 0.3 N/cm, average 0.55 N/cm.
EXAMPLE 9
[0064] Raw material: Chitosan fiber: linear density 2.0 dtex, fiber length 50 mm. The fiber contains 1% by weight of surfactant (Tween 20). The fiber's absorbency to the solution containing 8.298 g/l of sodium chloride and 0.368 g/l of calcium chloride dehydrate (solution A) is over 110%. Acylated chitosan fiber: fiber linear density 2.2 dtex, fiber length 50 mm. fiber's absorbency of a solution containing 8.298 g/l of sodium chloride and 0.368 g/l of calcium chloride dehydrate (solution A) is 800%. The fiber contains 1% weight of Tween 20.
[0065] 1900 g of chitosan fiber and 100 g of acylated chitosan fiber are blended and opened manually for 5 mins, then fed into a single cylinder card (Cuarnicard). The fibers are further blended into the hopper and the card, then opened and formed into a web. The web is crosslapped and needled into a nonwoven with a base weight of 180 gsm.
[0066] Cut the fabric into 10×10 cm, pack the dressing into pouches then sterilise the dressing by EtO.
[0067] The dressing has an absorbency of 7.2 g/g, a wet strength in CD direction of 6.9 N/cm, in MD direction of 4.8 N/cm, average 5.2 N/cm.
[0068] Wet Strength Test Method
[0069] The absorbency test for all samples of chitosan fiber, chemically modified cellulose fiber and all dressings followed the ISO standard ISO 13726-1: 2002 Part 1 Aspects of Absorbency.
[0070] The ISO standard described a Solution A as the test solution. The solution A is made up with 8.298 g/l of sodium chloride and 0.368 g/l of calcium chloride dihydrate and distilled water.
[0071] In order to get an accurate reading for the dressing's wet strength, particular when comparing samples manufactured at various conditions, the test for the dressing's wet strength was performed in the following method:
[0072] 1) Cut a 2 cm strip off a test specimen, the strip length shall be at least 7 cm. With a 10×10 cm wound dressing, it is preferably to cut the second sample at a 90 degree angle to the first sample, so that samples of both MD and CD directions can be obtained at the same time, as shown in FIG. 4 .
[0073] 2) Fold the sample in half, and place the sample into the test solution 3 which is contained in the container 2 . The test solution is Solution A as above. The height of the solution in the container shall be 2+/−0.5 cm.
[0074] 3) Make sure that the sample's folded end is placed at the bottom of the device. Leave the sample in the device for 30 seconds.
[0075] 4) Lift the sample out of the container, place the two ends of the sample which are still dry into the top and bottom clamps of the Tensile Tester. This will avoid the sample slippage during the tensile testing.
[0076] 5) The distance between two jaws is 50 mm and the travel speed of the top jaw is set at 100 mm/min.
[0077] 6) Record the maximum force (N) required to break the sample. It is recommended to test both strips of the same dressing (10×10 cm) at the same time period so that one with higher strength can be recorded as the CD, and the other as the MD.
[0078] The average wet strength is the average of CD and MD value. | A wound dressing with bacteriostatic and hygroscopicity, preparation method therefore, and the use thereof in preparing a product for treating chronic wounds. The dressing comprises chitosan fiber and modified cellulose fiber. | 27,530 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a rolling contact device such as a cam follower, used in the technical field of machine tool or the like, and more particularly to a rolling contact device which comprises a shaft having an outer track surface, an outer ring surrounding the shaft and having an inner track surfaces, and rolling elements disposed between the shaft and the outer ring in a relationship spaced apart from each other circumferentially of the shaft.
2. Description of the Prior Arts
Heretofore, there is known a rolling contact device of the above mentioned type, in which one end of the shaft is adapted to be secured to an element of a machine and the peripheral surface of the outer ring is made in rolling contact with a cam surface of a cam serving as a cam follower. Such a cam follower is disclosed, for example, in Japanese Patent Publication No. 54-20534. The rolling contact device of this type is also used for moving a machine element together with the rolling contact device along a guiding rail with one end of the shaft secured to the machine element and with the peripheral surface of the outer ring in rolling contact with the rail.
The above-mentioned rolling contact device of the prior art suffers from a problem that when a radial load exceeding a certain value, such as an impact load, is applied to the outer ring, permanent deformations or press traces occur on the contact portions of the track surface of the shaft, the rolling elements and the track surface of the outer ring, thereby deteriorating the precision of the device.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a rolling contact device which may solve the abovedescribed problem of the prior art.
According to the present invention, a rolling contact device comprises: a shaft having an outer track surface; an outer ring surrounding the shaft and having an inner track surface; rolling elements disposed between the shaft and the outer ring in a relationship spaced apart from each other circumferentially of the shaft, the outer peripheral surface of the outer ring being adapted to be in rolling contact with a track surface of an element of an apparatus; and an at least one abutting portion provided on each of the shaft and the outer ring; the abutting portions on the shaft and the outer ring being radially opposed to each other with a small gap defined therebetween, such that, when a radial load exceeding a predetermined value acts on the outer ring, the abutting portions may abut against each other, thereby reducing radial load acting on contact portions of the track surface of the outer ring, the rolling elements and the track surface of the shaft.
The above and other objects, features and advantages of the invention will become more apparent from the following description with reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a rolling contact device according to a first embodiment of the present invention.
FIG. 2 shows the function and the advantage of a rolling contact device of the present invention.
FIGS. 3, 4, 5, 6 and 7 show second, third, fourth, fifth and sixth embodiments of the present invention, respectively.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 shows a rolling contact device according to the first embodiment of the present invention.
The rolling contact device comprises a shaft 1 having an outer track surface la, an outer ring 2 surrounding the shaft 1 and having an inner track surface 2a, and rolling elements 3 arranged between the shaft 1 and the outer ring 2 in rolling contact with the track surface laof the shaft 1 and the track surface 2aof the outer ring 2. The rolling elements are composed of needle rollers arranged in a relationship spaced apart from each other circumferentially of the shaft 1. The shaft 1 is integrally formed with a flange 1bat its left end for preventing outer ring 2 from moving to the left and slipping out from the shaft 1.
The shaft 1 is formed with abutting portions 1c, 1dadjacent to the both ends of the track surface on each other, thereby relieving or reducing the load 1a, and the outer ring 2 includes abutting portions 1c, on each other, thereby relieving or reducing the load 1dlocated opposite to the abutting portions 1c, 1d, respectively. The abutting portions 1c, 1dand the abutting portions 2b, 2care opposite to each other with a gap G of a predetermined size or depth formed therebetween. When a radial load F, greater than a predetermined value, acts on the outer ring 2 and the outer ring deforms radially over a predetermined amount, the abutting portions abut on each other, thereby relieving or reducing the load acting on the contact portions of the track surface 2aof the outer ring 2, the rolling elements 3 and the track surface 2aof the shaft 1. In the first embodiment, the abutting portions 1c, 1dare constituted by annular projections located along the periphery of the shaft 1 adjacent to both axial ends of the track surface 1a. The outer ring 2 has an inner cylindrical surface of a constant diameter, and the ring portions 2b, 2cadjacent to the track surface 2aserve as the abutting portions.
The rolling contact device shown in FIG. 1 is used in such a manner that the shaft 1 is secured to a machine element (not shown) at the of the shaft, while the outer ring 2 is placed in contact with a cam, rail or the like. When a radial load F greater than a predetermined value is applied to the outer ring 2 while the ring 2 is in a rotating or not-rotating state, the radial deformation of the outer ring 2 towards the shaft 1 becomes equal to the gap G, and the abutting portions 2b, 2cabut on the abutting portions 1c, 1d. In this state, a part of the radial load is directly transferred to the shaft 1 through these abutting portions, thereby relieving or reducing load acting on the rolling contact portions of the device.
If a rolling contact device does not have the abutting portions 1c, 1d, 2b, 2c, the relation between a radial elastic deformation δ(mm) of the outer ring 2, maximum load Qm (kgf) acting on the rolling element, and an effective length La (mm) of each rolling element, is expressed, similarly to the case of a roller bearing, by the following equation: ##EQU1##
Assuming that a radial load corresponding to the basic static nominal load Co (kgf) of the device acts on the outer ring 2, the maximum load Qm on each rolling element can be calculated by the following equation (2), which Z designates the number of the rolling element 3. In such a rolling contact device of bearing under an usual operation, it is experimentally recognized that a deformation of a rolling element or a roller smaller than 1/10000 of the rolling element diameter is permitted without causing any operational trouble. Accordingly, a static load causing such permanent deformation is referred to as a basic static nominal load. ##EQU2##
The elastic deformation δof the outer ring 2 deduced from equations (1) and (2) is based on the assumption that no abutting portions 1c, 1d, 2b, 2care provided and a basic static nominal load is applied. By arranging the abutting portions 1c, 1d, 2b, 2cso as to make the gap G smaller than this elastic deformation δ, when a basic static nominal load is applied, the abutting portions 2b, 2calways abut on abutting portions 1c, 1d, thereby relieving the load acting on the rolling contact portions. In consequence, the above-mentioned gap G is preferred to be below the elastic deformation. In actual operation of the device, it is desired for the abutting portions 2b, 2cto slide along the abutting portions 1c, 1dwith a lubricant oil present in the gap G, similar to the case of a plane bearing. In such a case, the amount or size of the gap G is preferred to be a little greater than the sum of the elastic deformation of the outer ring caused when a maximum radial load (design load) is applied thereto in an usual operation of the device, and the allowable minimum thickness of a lubricant oil film for effecting a fluid lubrication.
FIG. 2 shows a relation between a radial load F (kgf) acting on the rolling elements and an outer ring deformation δ(mm). In the FIG., line X shows a theoretical characteristic of a device of a prior art which has no abutting portions such as lc, ld,2b, 2c. Line Y shows an example of a characteristic of the illustrated embodiment having the abutting portions 1c, 1d, 2b, 2c. Line Y shows a characteristic of the rolling contact device according to the illustrated embodiment of the present invention, where the size or depth of the gap G is made equal to the sum δ 3 of the outer ring maximum deformation δ, resulted from maximum radial load applied to the outer ring during usual operation and minimum allowable thickness δ 2 of the lubricant oil. As obvious from line X in FIG. 2, in the prior art, the deformation of the outer ring linearly increases substantially in proportion to the increase of the radial load, and reaches δ 4 when a radial load corresponding to the basic static nominal load Co acts on the outer ring. In an usual operation, that is in a radial load range below point Cb which corresponds to the outer ring displacement δ 1 , line X coincides with line Y, in other words, the function of the device of the present invention is identical to that of the device of the prior art. In the range between point Pb and point Pc at which the radial load is Cc and the deformation of the outer ring reaches the value δ 3 , the gap G gradually decreases from the allowable minimum thickness of the lubricant oil film. In this range, since the abutting portions 2b, 2cabut on the abutting portions 1c, 1dwith an oil film interposed therebetween the deformation of the outer ring increases along a gentle slope as the load increases. When the radial load reaches Cc corresponding to point Pc, the abutting portions 2b, 2cdirectly contact with the abutting portions 1c, 1dwith no oil film therebetween. When the radial load further increases beyond point Cc, the deformation of the outer ring linearly increases along a slope gentler than the above-mentioned slope between point 0 and point Pb due to the greater stiffness of the rolling contact device. In consequence, the basic static nominal load corresponding to the outer ring displacement δ 4 is Co in the prior art, while in the illustrated embodiment as indicated by line Y, it is Cx which is considerably greater than Co.
As mentioned above by referring to FIG. 2, since the outer ring deformation reaches δ 4 only when a greater load Cx is applied on the ring, permanent deformations of the rolling contact portions assumed to be caused by an impact load applied on the outer ring can be effectively prevented. Referring to line Y, in the range from Pb to Pc, the oil film gradually becomes thinner with an increasing frictional force accompanied, while in the range from Pc to Px, the abutting portions 2b, 2cdirectly abut on the abutting portions 1c, 1dwith no oil film therebetween, making it difficult for the outer ring to rotate. Therefore, when a radial load greater than Cb, particularly the load greater than Cc, is applied on the outer ring which is in a rotating state, the rotation of the ring may be abruptly stopped in an inconvenient manner. Consequently, it may be said that the rolling contact device of the present invention is most suitable to be used for a device sufferring an impact load which may be applied in a stationary state of the device., For example, the rolling contact device of the present invention may be used in an intermittent index device which transforms a continuous rotary motion of an input shaft to an intermittent rotary motion of an output shaft through a cam and rolling contact devices. In this case, there is the possibility that a large radial impact load may be applied to the outer rings of the rolling contact devices during the intermittent period for which the output shaft and hence the outer rings are in a stationary state, but no permanent deformation of the rolling contact portions may be caused by the impact load.
Line Y in FIG. 2 corresponds to a case where the gap G is made equal to the outer ring deformation δ 3 . However, the gap G may also be selected to be greater than the elastic deformation δ 3 , as mentioned before.
FIG. 3, FIG. 4 and FIG. 5 show second, third and fourth embodiments of the present invention, respectively. In the second embodiment shown in FIG. 3, annular abutting portion 1cand the opposite abutting portion 2bprovided in the first embodiment shown in FIG. 1 are omitted, and a flange portion 2bis provided on the shaft 1 for abutting on the left end of the rolling elements 3. On the other hand, similarly to the first embodiment, shaft 1 is formed with an annular projection or abutting portion ldadjacent to the right end of the rolling elements 3, which is opposite to abutting portion 2cof the outer ring 2. In the third embodiment shown in FIG. 4, the shaft 1
track surfaces 1aand 1aaxially separated from each other. A plurality of rolling elements 3' are arranged around the track surface la`, while a plurality of rolling elements 3"are arranged around the track surface 1a". The outer ring 2 having the track surface 2ais arranged around these rolling elements 3' and 3". The shaft 1 is formed with an annular projection 1edisposed between the track surface 1a`and the track surface 1a", which constitutes an abutting portion of the shaft 1. The outer ring portion opposite to the projection 1ewith a small gap G constitutes an abutting portion 2dof the outer ring 2. In the fourth embodiment shown in FIG. 5, the shaft 1 has a left end portion which has a substantially constant outside diameter greater than that of the right side portion of the shaft, and rolling elements 3 and outer ring 2 are mounted on this left end portion. In this fourth embodiment, the bottom surface of an annular groove formed in the inner surfaces of the outer ring 2 constitutes a track surface 2aof the outer ring 2, the outer ring portions adjacent to the ends of the track surface 2aconstitute abutting portions 2b, 2cof the outer ring 2, and the shaft portions opposite to the abutting portions 2b, 2cconstitute abutting portions 1c, 1dof the shaft 1.
Since in the second, third and fourth embodiments, the features other than those described above are similar to those of the first embodiment, such similar features are indicated by the same reference numbers or marks, and detailed descriptions thereof are omitted. The gap G is determined in the second, third, or fourth embodiment similarly to the first embodiment.
FIG. 6 shows a fifth embodiment of the present invention. The rolling contact device of this embodiment is of a so-called roller follower type, and comprises a shaft 10 having a constant diameter and a track surface 10aat its periphery, an outer ring 12 having a constant inside diameter and a track surface 12a, and a plurality of rolling elements 13 disposed 5 between the shaft and the outer ring at circumferential intervals and in rolling contact with the track surfaces 10aand 12a. The shaft 10 is formed with annular projections adjacent to the both ends of the track surface 10a, which constitute abutting portions 10c, 10dof the shaft 10. Outer ring portions opposite to the abutting portions 10c10d constitute abutting portions 12b, 12cof the outer ring 12 with a small gap G formed therebetween.
FIG. 7 shows a sixth embodiment of the present invention. In this embodiment, the shaft 10 is not formed with any annular projections such as the abutting portions 10c, 10dseen in the fifth embodiment. Instead, an outer ring 12 is formed with an annular inner groove, the bottom of which constitutes a track surface 12a, and outer ring portions adjacent to the both ends of the track surface 12aconstitute abutting portions 12b, 12c. Portions of shaft 10 opposite to the abutting portions 12b, 12cconstitute abutting portions 10c, 10 dof the shaft 10 with a small gap G formed therebetween. Other features of the sixth embodiment are similar to those of the fifth embodiment.
The size of the gap G in the fifth and sixth embodiments is determined in the same manner as in the first embodiment.
As mentioned above, the rolling contact device of the present invention brings about such advantages as to a decrease of the probability of permanent deformations of the device at its rolling contact portions, when an impact load of the like acts on the outer ring of the device. | A rolling contact device having a shaft adapted to be secured to an element of an apparatus, an outer ring adapted to be in rolling contact with another element of the apparatus, and rolling elements disposed between the shaft and the outer ring, includes an abutting portion provided on each shaft and the outer ring, the abutting portions on the shaft and the outer ring being opposed to each other with a small gap defined therebetween. These abutting portions are arranged such that, when an excessive radial load is applied to the outer ring, the abutting portions are brought into contact with each other to prevent permanent deformation of rolling contact portions of the device. | 16,858 |
CROSS-REFERENCE TO RELATED APPLICATIONS
Not applicable.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not applicable
REFERENCE TO A "MICROFICHE APPENDIX"
Not applicable
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the disassembly or unthreading of pipe, specifically of oil and gas well drilling pipe and more particularly to an improved method and apparatus for enabling a user to disassemble or destab joints of oil field drill pipe and the like even in offshore marine conditions, e.g. on semisubmersible rigs and the like. Even more particularly, the present invention relates to an improved destabbing apparatus and its method of use wherein a cylindrically shaped sleeve having a hinged body enables the sleeve to be assembled and disassembled to a pair of connected joints of pipe, the lower end of the sleeve having a cam and clamp arrangement that securely fastens the sleeve to the lower of the two pipe joints enabling a user to "destab" (disassemble) the upper joint while the sleeve grips the lower joint.
2. General Background of the Invention
In the oil and gas well drilling industry, it is common to employ drill strings that are comprised of a number of lengths of drill pipe that are connected end to end. In some particular types of joints such as those that employ wedge threads, dovetail threads, taper threads and the like, excess thread wear and thread damage can more easily occur during destabbing operations. Further, rough seas cause floating oil well drilling vessels to pitch so that aligning pipe sections is difficult.
BRIEF SUMMARY OF THE INVENTION
The present invention provides an improved method of destabbing or disconnecting a pair of threadably interengaged and generally vertically oriented oil and gas well drill pipe sections that are connectable end to end at threaded pin and box joint connections.
The method first provides a pair of pipe joints to be joined, each having end portions with mating faces and threaded portions that are connected to similarly threaded portions of another joint.
During destabbing, a sleeve is affixed to the assembly of the pipe joints at the mating faces, wherein a lower end portion of the sleeve engages the lower joint and an upper end portion of the sleeve engages the upper joint.
The joints are then "destabbed" by rotating the upper joint relative to the lower joint and wherein the sleeve tightly engages the lower joint.
During this method, the longitudinal axes of the joints are maintained in alignment. The present invention also provides a pipe destabbing apparatus for disconnecting a pair of threadably connected pipe joints having threaded end portions and mating faces at the end portions.
The apparatus includes a sleeve having a pair of connected sections, means on the sleeve sections for enabling a user to manipulate the sleeve sections during use, at least one of the sleeve section having a window, the lower end of the sleeve having a compressive member for pressing the sleeve against the lower joint of the pair of assembled joint of pipe, and wherein the window enables the user to position the mating faces at the middle of the sleeve by visual inspection.
The upper end of the sleeve closely conforms to the upper joint of pipe and the compressive member applies sufficient load to the assembled joints at the lower joint so that when the two joints are rotated with respect to one another during disassembly or destabbing, the lower joint is affixed to the sleeve and the upper joint rotates with respect to the sleeve and lower joint.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the preferred embodiment of the apparatus of the present invention;
FIG. 2 is a perspective view of the preferred embodiment of the apparatus of the present invention illustrating the destabbing of one joint of pipe from another joint of pipe;
FIG. 3 is a perspective view of the preferred embodiment of the apparatus of the present invention; and
FIG. 4 is a top view of the preferred embodiment of the apparatus of the present invention;
FIG. 5 is a top view of the preferred embodiment of the apparatus of the present invention showing the body in an open position;
FIG. 6 is an elevational view of the preferred embodiment of the apparatus of the present invention; and
FIGS. 7-8 are fragmentary views showing the locking cam position.
For a further understanding of the nature, objects, and advantages of the present invention, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein:
DETAILED DESCRIPTION OF THE INVENTION
FIGS. 1-6 show generally the preferred embodiment of the apparatus of the present invention designated generally by the numeral 10. Destabbing apparatus 10 includes a cylindrically shaped sleeve in the form of two semicircular clamp sections 21, 22 as shown in FIGS. 1-4. In the oil and gas well drilling industry, stabbing means to thread one joint of drill pipe that is vertically oriented into another joint of drill pipe that is vertically oriented such as occurs when running a drill string into the well. "Destabbing" refers to the disassembly or unthreading of an upper vertically oriented joint from a lower joint, such as occurs when pulling a pipe string out of a well. In FIGS. 2 and 6, a pair of joints of drill pipe are connected end to end including a lower joint 11 and an upper joint 12. The lower joint 11 provides a box end portion 13. The upper joint 12 provides a pin end portion 14. Each of the joints 11, 12 provides a longitudinally extending, typically cylindrically shaped open ended flow bore 15, 16 respectively.
Each of the joints 11, 12 provides a wall 17, 18 respectively. In FIG. 1, a rotation of the upper joint 12 with respect to the lower joint 11 in the direction of arrow 19 enables the threads at the box and pin end portions 13, 14 to be disassembled or "destabbed" so that the joint 12 can be separated from the joint 11 in the direction of arrow 20.
In FIGS. 1-5, destabbing apparatus 10 is the form of a cylindrically shaped sleeve that includes clamp sections 21, 22 connected together with upper and lower hinges 23. Handles 24, 25 enable a user to grip the respective clamp sections 21, 22 during assembly and during disassembly of the apparatus 10 to a pair of connected joints 11, 12.
A pair of windows 26, 27 are provided respectively upon clamp sections 21, 22 as shown in FIGS. 1, 2, 3 and 6. The windows 26, 27 enable a user to place the apparatus 10 in the correct position upon a pair of assembled joints 11, 12. Preferably, the respective lower end portions 45, 46 of the windows 26, 27 are placed immediately below the upper transverse surface 47 of the lower joint 11, a distance indicated by arrow 48 as shown in FIG. 6. In this fashion, the user ensures that the apparatus 10 will be clamped to the upper end of the lower joint 11.
Because the upper end portion of the clamped sections 21, 22 are not provided with a clamp mechanism (such as the mechanism 40 at the bottom of the apparatus 10), only the bottom part of the apparatus 10 is tightly clamped to the lower joint 11. This construction enables the upper joint 12 to rotate freely with respect to the clamp sections 21, 22 during destabbing. Each of the clamp sections 21, 22 provides and upper annular edge 28 and a lower annular edge 29. The windows 26, 27 are space downwardly from the upper annular edge 28 and upwardly from the lower annular edge 29 as shown in FIG. 3.
Clamp mechanism 40 is shown more particularly in FIGS. 3-4 and 6-8. Clamp mechanism 40 is mounted at weldment 42 to clamp section 21. The weldment 42 carries a square block like body 39 with a central longitudinal bore 43 through which threaded fastener 37 passes. Threaded fastener 37 attaches at hinge 36 to link 32. The opposite end of threaded member 37 carries washer 41 and nut 43.
Spring 38 is positioned in between body 39 and washer 41 as shown in FIG. 4. Handle 33 is pivotally attached at pivot 34 to link 32. Cam 35 at one end of handle 33 is provided for engaging the recess 31 of catch 30. In order to close clamp sections 21, 22, a user holds knob 47 of handle 33 and manipulates the handle 33 until cam roller 49 engages the recess 31. The user then rotates the handle 33 in the direction of arrow 44 in FIGS. 4 and 8.
Cam roller 49 engages recess 31 of catch 30 that is welded to clamp section 22. Continued rotation of handle 33 in the direction of arrow 44 similarly rotates cam roller 49 in the direction of arrow 50. Cam links 51, 52 nest in between links 32 as shown in FIGS. 4, 6-7 as closure is completed.
Tension in spring 38 can be varied by tightening or loosening nut 37 on threaded fastener 37 to vary the distance between washer 41 and block 39. When handle 33 is rotated to the fully closed position of FIG. 4, threaded fastener 37 moves relative to bore 43 so that spring 38 can be compressed to load the connection of cam roller 49 to catch 30.
The inside surfaces of clamp sections 21, 22 are curved to conform to the outer surfaces of pipe sections 11, 12. However, the inside surfaces of the clamp sections 21, 22 can be slightly cut away above a horizontal line 53 that is also represented by transverse face 47 of lower joint 11 (see FIG. 6).
Such a cut-away surface could be a few, for example only a few tenths of a millimeter, allowing upper joint 12 to rotate a little more freely relative to lower joint 11 during destabbing. However, it has been found that the inside surfaces 54, 55 of respective clamp sections 21, 22 can define a cylinder with uniform transverse cross section since clamp mechanism 40 tightly grips lower section 11 during destabbing.
The following table lists the parts numbers and parts descriptions as used herein and in the drawings attached hereto.
______________________________________PARTS LISTPart Number Description______________________________________10 destabbing apparatus11 joint12 joint13 box end14 pin end15 flow bore16 flow bore17 wall18 wall19 arrow20 arrow21 clamp section22 clamp section23 hinge24 handle25 handle26 window27 window28 upper edge29 lower edge30 catch31 recess32 link33 handle34 pivot35 cam36 pivot37 threaded member38 spring39 body40 clamp mechanism41 washer42 weldment43 nut44 arrow45 lower end portion46 lower end portion47 knob48 arrow49 cam roller50 arrow51 cam link52 cam link53 line54 inside surface55 inside surface______________________________________
The foregoing embodiments are presented by way of example only; the scope of the present invention is to be limited only by the following claims. | A method and apparatus for destabbing (disassembling) two vertically oriented drill pipe joint sections provides a two part clamp arrangement that holds the assembled joint at their interface. A lower end of the clamp arrangement is tightly clamped to the lower joint so that the upper joint rotates when the two joint are gripped with power tongs or like pipe handling devices and unthreaded or "destabbed". | 12,766 |
The research leading to the present invention was supported, at least in part, by grant CA42567 from the National Cancer Institute, also by funds from the NIH Medical Scientist Training Program (grant number GM07739). Accordingly, the Government may have certain rights in the invention.
BACKGROUND
This invention relates to the field of enzyme inhibitors, especially inhibitors of histone acetyltransferases.
The molecular identification of a number of histone acetyltransferases (HATs) has led to new insights into the mechanisms of activation of gene expression (Mizzen and Allis, 1998; Stuhl, 1998). The members of this growing family include the important transcription factors p300/CBP and PCAF (Yang et al., 1996; Ogryzko et al., 1996; Bannister and Kouzarides, 1996). PCAF and p300/CBP can catalyze the acetylation of histones (Yang et al., 1996; Ogryzko et al., 1996; Bannister and Kouzarides, 1996) and other substrates (Wu and Roeder, 1997) and these HATs have been suggested to play differential roles in coactivation of gene expression. The HAT domain of PCAF appears to be involved in MyoD-dependent coactivation and differentiation, whereas that of p300 seems to be less important (Puri et al., 1997). A role for the acetyltransferase activity of PCAF was also suggested for transcriptional activation by the liganded retinoic acid receptor (RAR). The PCAF acetyltransferase domain but not that of CBP can assist retinoic acid induced transcription in cultured cells that are depleted of endogenous PCAF and CBP by antibody microinjection (Korzus et al., 1998). On the other hand, the acetyltransferase domain of CBP and not that of PCAF can contribute to CREB-activated transcription in PCAF- and CBP-depleted cells (Korzus et al., 1998). These experiments suggest differential requirements for PCAF and p300/CBP in the coactivation of various sequence-specific DNA binding transcriptional activators. However, none of these studies has established directly that acetyltransferase action or histone acetylation per se is involved in these activation processes.
Because of the possibility that PCAF and p300 proteins physically interact (Ogryzko et al., 1996), their relative contributions toward acetylation of substrates and gene activation is not generally known. While mutations in the active site regions of these enzymes can help clarify these issues, the effects of such mutations on altering protein structure and stability can complicate interpretations. Small molecules have been useful in elucidation of the general role of histone acetylation in transcription by blocking histone deacetylase (Taunton et al., 1996). It would be advantageous to apply active-site directed, specific, and potent synthetic inhibitors of individual HAT enzymes to dissect their relative roles in protein acetylation and transcription. Furthermore, there is a basis for expecting that the blockade of p300 HAT activity would have therapeutic potential in the treatment of certain cancers (Giles et al., 1998).
Prior to the molecular characterization of specific HAT enzymes, several polyamine-CoA conjugates were found to block HAT activities present in cell extracts (Cullis et al., 1982; Erwin et al., 1984). However the actual enzyme or enzymes inhibited have not been characterized. We have shown that one of these synthetic inhibitors (Cullis et al., 1982) potently blocks non-chromatin template mediated transcription and therefore would not be useful in the determination of the role of HAT activity in gene activation unpublished data.
PCAF belongs to a superfamily of GNAT (GCN-5 related N-acetyltransferases) acetyltransferases whose three-dimensional structures have recently been reported (Coon et al., 1995; Neuwald and Landsman, 1997; Wolf et al., 1998; Dutnall et al., 1998; Wybenga-Groot et al., 1999; Hickman et al., 1999a; Hickman et al., 1999b; Lin et al., 1999). Family members most likely catalyze acetyl transfer in a ternary complex containing enzyme, histone, and acetyl-CoA (De Angelis et al., 1998; Tanner et al., 1999). Bisubstrate analog inhibitors have proved successful for the GNAT family member serotonin N-acetyltransferase (Khalil et al., 1998; Khalil et al., 1999). Here we report on bisubstrate analog inhibitors and their effects on histone acetylation and transcription.
SUMMARY OF THE INVENTION
The invention in a general aspect is a histone acetyltransferase inhibitor. Such inhibitors are useful both as analytical reagents for studying the role of histone acetyltransferases in the regulation of gene expression. They are also useful for inhibiting acetyltransferase in diseased cells that overexpress such acetyltransferase.
In a particular embodiment of the invention, the inhibitor is Coenzyme A (CoA) covalently linked (preferably via a —CO— bridge to a lysine ε-amino group) to lysine or a polypeptide comprising lysine. Inhibitors that are specific for p300 acetyltransferase are those in which the CoA is linked to lysine or a very short polypeptide (2 to 6 amino acids) comprising lysine. Such inhibitors will inhibit p300 acetyltransferases (“p300 inhibitors”) more significantly (at least 100 times as much) than they inhibit PCAF acetyltransferases. Inhibitors that are specific for PCAF acetyltransferases (“PCAF inhibitors”) are those in which the CoA is linked to lysine in longer polypeptides (8 or more amino acids.) Such inhibitors will inhibit PCAF acetyltransferases (“PCAF inhibitors”) more significantly (at least 100 times as much) than they inhibit p300 acetyltransferases.
In another aspect, the invention is histone acetylase inhibitors that will inhibit transcription of a histone-associated DNA sequence more strongly than the identical DNA sequence not associated with histones (especially, naked DNA). Such inhibitors are the p300 inhibitors and PCAF inhibitors.
In another general aspect, the invention is the process of administering a histone acetyltransferase inhibitor to a host, the host being an animal or human. Such a process is done for therapeutic purposes in cases where it is beneficial to the host to have a histone acetyltransferase inhibited. That is the case, for example, in certain types of cancers. It can also be the case in certain gene therapy protocols.
A preferred histone acetyltransferase inhibitor of the present invention is one with the structure
where the H is [CHR 11 ] is absent if R 11 is oxygen
where n is an integer in the range 0 to 2;
where R 1 , R 2 , and R 10 are independently selected from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, pentyl, vinyl, ethinyl, allyl, methyloxy, ethyloxy, propyloxy, butyloxy, and pentyloxy;
where R 11 for each R 11 is independently selected (e.g., if n is 3, there are three R 11 moieties that can be independently selected) from the group consisting of hydrogen, methyl, ethyl, propyl, butyl, pentyl, vinyl, ethinyl, allyl, methyloxy, ethyloxy, propyloxy, butyloxy, pentyloxy fluoro, chloro, bromo, iodo, hydroxy, carboxy, and oxygen,
where carboxy is
wherein R 12 is hydrogen, methyl, ethyl, propyl, or isopropyl,
where R 8 is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, vinyl, ethinyl, allyl, methyloxy, ethyloxy, propyloxy, butyloxy, pentyloxy, an amino acid or a polypeptide comprising two amino acids, provided that if R 8 is an amino acid or polypeptide, said amino acid or polypeptide may have a protective group (e.g., it is acetylated) at its N terminus. The intent of the protective group is to provide ptrotection during the compound's synthesis.
Where R 9 is selected from the group consisting of methyl, ethyl, propyl, butyl, pentyl, vinyl, ethinyl, allyl, methyloxy, ethyloxy, propyloxy, butyloxy, pentyloxy, an amino acid acetylated at its N terminus, or a polypeptide of two or more amino acids; and pharmaceutically acceptable salts thereof.
Inhibitors of interest that are analogs of Lys-CoA are also shown in FIG. 7, (R 6 and R 7 in FIG. 7 correspond to R 8 and R 9 , respectively.) For H3-20-CoA analogs of interest include those with substitutions in the lysine moiety similar to those shown for Lys-CoA. In addition, truncations and substitutions of the other amino acids in the peptide backbone using combinatorial approaches can be performed to create analogs.
Specific embodiments of interest are:
those wherein R 8 , in combination with the carbonyl group adjacent to R 8 , is an amino acid or a polypeptide of two or more amino acids;
those wherein R 9 is an amino acid or a polypeptide of two or more amino acids;
those wherein R 8 , in combination with the carbonyl group adjacent to R 8 , is an amino acid of a polypeptide of two or more amino acids, and R 9 is an amino acid or a polypeptide of two or more amino acids.
Specific inhibitors of p300 acetyltransferase are preferably:
those wherein R 8 , in combination with the carbonyl group adjacent to R 8 , is an amino acid, especially where the amino acid is Gly;
those wherein R 9 is an amino acid or a polypeptide of 2 or 3 amino acids, especially where R 9 is selected from the group consisting of Gly, Gly-Leu, and Gly-Lys-Gly (such that the leftmost amino acid is the one closest to the NH group adjacent to the R 9 group); and
those where wherein R 8 is methyl and R 9 is hydrogen (also referred to as Lys-CoA herein).
Specific inhibitors of PCAF acetyltransferase are preferably:
those wherein R 8 , in combination with the carbonyl group adjacent to R 8 , is a polypeptide comprising at least three amino acids, especially where the three amino acids are those of Gly-Gly-Thr and in that sequence;
those wherein R 8 , in combination with the carbonyl group adjacent to R 8 , comprises a polypeptide of at least 8 amino acids especially where the eight amino acids are those of Thr-Ala-Arg-Lys-Ser-Thr-Gly-Gly- (SEQ ID NO:1) and in that sequence:
those wherein R9 is a polypeptide of at least 5 amino acids, especially where the 5 amino acids are those of Ala-Pro-Arg-Lys-Gln (SEQ ID NO:2) and in that sequence; and
those where R8 is (N-acetyl)-Ala-Arg-Thr-Thr-Lys-Gln-Thr-Ala-Arg-Lys-Ser-Thr-Gly-NH-CH 2 - in that sequence, wherein the peptide portion of R 8 is SEQ ID NO:3, and R9 is the polypeptide Ala-Pro-Arg-Lys-Gln-Leu (SEQ ID NO:4) in that sequence.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 . Design and synthesis of peptide CoA conjugates.
FIG. 1 A: Coupling reactions.
FIG. 1 B: Peptide synthesis
FIG. 2 . Evaluation of Lys-CoA as a HAT inhibitor.
FIG. 2 A: Autoradiographic analysis of p300 HAT inhibition by Lys-CoA. Lanes 1-5 employed 0, 0.1, 0.5, 2.5, and 10 μM concentrations of Lys-CoA. Images bands are histones H4 (top) and H3 (bottom).
FIG. 2 B: Bar graph analysis of p300 HAT Inhibition by Lys-CoA at the concentrations indicated, quantitated using Phosphorimage analysis (Molecular Dynamics). HAT activity is normalized to 100% for no added inhibitor.
FIG. 2 C: Bar graph analysis of PCAF HAT Inhibition by Lys-CoA at the concentrations indicated, quantitated using Phosphorimage analysis (Molecular Dynamics). HAT activity is normalized to 100% for no added inhibitor. Standard error was found to be ±20% for duplicate runs.
The sequence Ala-Pro-Arg-Lys is SEQ ID NO:5. The sequence Gly-Leu-gly-Lys is SEQ ID NO:6. The sequence Ala-Arg-Thr-Lys-Gln-Thr-Ala-Arg-Lys-Ser-Thr-Gly-Gly, which is represented in the Figure in reverse direction (from right to left), is SEQ ID NO:8. The sequence Ala-Pro-Arg-Lys-Gln-Leu is SEQ ID NO:4. The sequence Ser-Gly-Arg-Gly-Lys-Gly-Gly, which is represented in the Figure in reverse direction is SEQ ID NO:9. The sequence Gly-Leu-Gly-Lys-Gly-Gly-Ala-Lys-Arg-Asn-Arg-Ala is SEQ ID NO:10. The entire sequence for H3-CoA-7 is SEQ ID NO:11. The entire sequence for H4-CoA-7 is SEQ ID NO:12. The entire sequence for H3-CoA-20 is SEQ ID NO:13. The entire sequence for H4-CoA-20 is SEQ ID NO:14.
FIG. 3 . Assessment of p300 and PCAF HAT activities in p300/PCAF.
FIG. 3 A: p300 and PCAF HAT activities with mixed histones as substrates. Bar 1, PCAF alone without inhibitors; Bar 2, p300 alone without inhibitors; Bar 3; PCAF+p300 without inhibitors; Bar 4, PCAF+p300+Lys-CoA (30 μM); Bar 5, PCAF+p300+H3-CoA-20 (30 μM); Bar 6, PCAF+p300+Lys-CoA (30 μM)+H3-CoA-20 (30 μM). Activities were normalized to 100% for Bar 3. Standard error was found to be ±20% for duplicate runs.
FIG. 3 B: p300 and PCAF HAT activities with nucleosomes as substrates. Bar 1, PCAF alone without inhibitors; Bar 2, p300 alone without inhibitors; Bar 3; PCAF+p300 without inhibitors; Bar 4, PCAF+p300+Lys-CoA (20 μM); Bar 5, PCAF+p300+H3-CoA-20 (15 μM); Bar 6, PCAF+p300+Lys-CoA (20 μM)+H3-CoA-20 (15 μM). Activities were normalized to 100% for Bar 3. Standard error was found to be ±20% for duplicate runs.
FIG. 4 . Lys-CoA inhibits p300 HAT activity dependent transcription activation. FIG. 4 A: Outline of the in vitro transcription protocol.
FIG. 4 B and C: Transcription from naked DNA and chromatin templates. DNA (28 ng) and freshly assembled chromatin templates (with an equivalent amount of DNA) were incubated with or without activator, Gal4-VP16 (30 ng) for 20 min at 30° C.; 25 ng of baculovirus expressed, highly purified p300 (full length) and 1.5 μM of acetyl-CoA were added as indicated. Following the addition of nuclear extract (source of general transcription factors) and NTPs, transcription reactions were incubated and processed as described. Before adding it to the reaction, p300 was incubated (4° C., 20 min) with or without inhibitors: without inhibitor (panel C, lanes 2 and 9), 10 μM Lys-CoA (panel C, lanes 3 and lane 10) or H3-CoA-20 (Panel C, lanes 4 and 11).
FIG. 5 . Acetyl-CoA.
FIG. 6 . Cell permeable analog development.
FIG. 7 . Inhibitory lysine analogs.
FIG. 8 . Evaluation of H3-CoA-20 as a HAT inhibitor.
FIG. 8 A: H3-CoA-20 p300 HAT inhibition.
FIG. 8 B: H3-CoA-20 PCAF inhibition.
DETAILED DESCRIPTION OF THE INVENTION
Amino acid abbreviations
“Ala” represents alanine, “Asn” represents asparagine, “Lys” represents lysine, “Leu” represents leucine. “Thr” represents threonine, “Ser” represents serine, “Arg” represents arginine, “Pro” represents proline, “Gln” represents glutamine.
Pharmaceutical aspects of the invention
In a preferred embodiment, a prodrug represented by Lys-X is used in order that enzymes within the cell, especially HAT enzymes, can catalyze alkyl transfer to CoASH so as to generate the potent p300 inhibitor Lys-CoA within the cells. Lys-X is expected to be cell permeable because it is small, relatively hydrophobic and unchanged. Upon conversion to Lys-CoA within cells, it would be “trapped” in the cell and thereby a potent p300 inhibitor. (See FIG. 6.) This strategy was shown to be effective in a related system with serotonin N-acetyltransferase (E. M. Khalil et al., PNAS, vol. 96, pp. 12418-12423, 1999).
In another option, Lys-pantetheinyl derivatives are administered. The further elaboration of Lys-panteheine or Lys-pant-phosphate within cells can be predicted based on the known cellular enzymes that convert pantetheine and phosphopantetheine to coenzyme A. (See FIG. 6.) Indeed, we have shown (unpublished data) that this appears to take place for an indole-pantetheine derivative.
A general approach to making peptide agents cell permeable is to covalently attach them to short membrane permeable sequences (Rojas M. Donahue JP. Tan Z. Lin YZ. Genetic engineering of proteins with cell membrane permeability. Nature Biotechnology, 16(4):370-5, 1998 April and references therein). This is another option for both Lys-CoA and H3-20-CoA.
4) Liposomes and cationic lipids might also be used to deliver the HAT inhibitors inside cells.
Pharmaceutical preparations of the compounds of the invention would include pharmaceutically acceptable carriers, or other adjuvants as needed, and would be prepared in effective dosage ranges as needed.
Generally, the inhibitors (or precursors thereof capable of being correctly processed in the host or the host's cells) of the invention may be formulated for intraarterial, intraperitoneal, intramuscular, subcutaneous, intravenous, oral, nasal, rectal, bucal, sublingual, pulmonary, topical, transdermal, or other routes of administration. Comprehended by the invention are pharmaceutical compositions comprising effective amounts of inhibitors of the invention together with pharmaceutically acceptable diluents, preservatives, solubilizers, emulsifiers, adjuvants and/or carriers. Such compositions include, for example, aqueous diluents of various buffer content, incorporation of the material into particulate preparations of polymeric compounds such as polylactic acid, polyglycolic acid, etc. or into liposomes. The compositions may be prepared in liquid form, or may be in dried powder, such as lyophilized form.
Solid dosage forms include tablets, capsules, pills, troches or lozenges, cachets or pellets. Also, liposomal or proteinoid encapsulation may be used to formulate the present compositions (as, for example, proteinoid microspheres). Liposomal encapsulation may be used and the liposomes may be derivatized with various polymers.
Appropriate dosage levels for treatment of various conditions in various patients will depend on the patient and the therapeutic purpose. Generally, for injection or infusion, dosage will be between 0.01 μg of biologically active inhibitor/kg body weight and 10 mg/kg. The dosing schedule may vary, depending on the circulation half-life of the inhibitor (or its precursor) whether, for example, the inhibitor is delivered by bolus dose or continuous infusion, and the formulation used.
Results and discussion
We synthesized Lys-CoA and the other peptide CoA conjugates shown in FIG. 1 . Modification of the ε-amino group of the lysine was carried out in one pot, first coupling the amine with bromoacetic acid followed by reaction of the α-bromo-acetamide function with CoASH (FIG. 1 A). Partially, protected peptides were produced by solid phase peptide synthesis using the Fmoc strategy. Selective modification of the desired lysine in the context of other lysine residues was achieved using orthogonal protection with the dimethyldioxocyclohexylidene (Dde) protective group. It was necessary to carry out the CoA conjugation step after cleaving the peptides from the resin because of the presumed lability of the lycosidic linkage in CoA in the presence of strong acid conditions. Each peptide CoA conjugate (FIG. 1B) was purified to homogeneity (>95%) by reverse phase HPLC, and electrospray mass spectrometry was used to verify structural integrity. These compounds were stable in solution under long term storage conditions (>6 mos) at −80° C.
Screening of the peptide CoA conjugate for inhibition of HAT activity of PCAF and p300 was carried out according to standard HAT assay procedures (Ogryzko et al., 1996; Yang et al., 1996; Schiltz et al., 1999) using commercially available mixed calf histone substrates. As can be seen, Lys-CoA was found to be a potent and selective inhibitor of p300 acetyltransferase activity with an IC 50 of approximately 500 nM (FIG. 2, Table 1). Under similar conditions, the IC 50 of Lys-CoA for PCAF inhibition was approximately 200 μM. Neither of the heptapeptide-CoA conjugates was effective at inhibiting p300 or PCAF (Table 1). H3-CoA-20 proved to be very effective at inhibiting PCAF HAT activity (IC 50 =300 nM) but showed little ability to block p300 (IC 50 =200 μM) (FIG. 8, Table 1). Interestingly, H4-CoA-20 was a poor inhibitor of both p300 and PCAF (Table 1). Neither the H3-20 peptide (which lacked CoA attachment) nor CoASH itself were potent HAT inhibitors (Table 1). That the H3-CoA-20 conjugate required the covalent attachment of the histone H3 20 amino acid peptide to CoASH was confirmed by showing that an equimolar mixture of free peptide and CoASH was poorly able (IC 50 >10 μM) to block PCAF HAT activity (data not shown).
Regarding inhibition results with PCAF, there is enhanced inhibition by an H3-20-CoA conjugate over an H4-20-CoA conjugate, a degree of selectivity >100-fold). Inhibition of PCAF was not achieved by the shorter conjugate H3-CoA-7. This suggests that key binding interactions between the PCAF enzyme and the histone H3 substrate lie outside the nearest neighboring residues and are mediated more broadly over the substrate sequence.
The potent inhibition of p300 by Lys-CoA but by none of the other peptide-CoA conjugates was an unexpected finding. That incorporation of longer peptide sequences derived from the histone H4 or H3 substrate into the bisubstrate analog actually reduces binding affinity is not readily explicable. These results are particularly striking since Lys-CoA actually lacks positive charges, a hallmark of the N-terminal regions of the substrates histone H3 and histone H4. These findings strongly suggest that p300 has a significantly different catalytic mechanism or mode of substrate binding compared to PCAF and other GNAT superfamily members, reflecting its lack of sequence homology.
With potent and specific HAT inhibitors in hand, one can exploit these molecules in further biochemical analysis. Since p300 and PCAF may form a complex and since each catalyzes acetyltransferase activity, the availability of inhibitors allows an opportunity to investigate the precise contributions of each enzyme present in a PCAF/p300 mixture toward histone acetylation. As can be seen in FIG. 3A, the combination of PCAF and p300 (present together) leads to an increased histone acetylation rate compared to either enzyme working alone (compare bars 1 and 2 with bar 3). In principle, this increase could have arisen in two ways: i) simple summing of the two enzyme activities without synergism or antagonism, or ii) stimulation of enzyme A by enzyme B with concomitant antagonism of enzyme B by enzyme A. Here, application of Lys-CoA and H3-CoA-20 inhibitors proved useful in distinguishing between these possibilities. It was observed that in the presence of Lys-CoA, the PCAF/p300 mixture resulted in acetylation that was similar to the rate of PCAF alone (compare bar 1 and bar 4) whereas in the presence of H3-CoA-20, the PCAF/p300 mixture resulted in acetylation that was similar to the rate of p300 alone (compare bar 2 and bar 5). Moreover, addition of both Lys-CoA and H3-CoA-20 to the PCAF/p300 mixture abolished nearly completely histone acetylation (bar 6). Furthermore, the pattern of histone acetylation (histone H3 vs. H4) reflected that expected for PCAF in the presence of Lys-CoA and that expected for p300 in the presence of H3-CoA-20 (data not shown). These results suggest that with purified histone mixtures, PCAF and p300 act independently when present together (without synergism or antagonism) to acetylate histones.
Given that physiologic substrates for p300 and PCAF are likely to be histones bound to DNA in nucleosomal structure, it was important to establish that selectivity of the inhibitors Lys-CoA and H3-CoA-20 could be achieved in this setting. As nucleosomes are much poorer substrates for HAT enzymes compared to free histones, it was necessary to use larger quantities of each of the enzymes (˜5-10-fold greater) and allow acetylation to take place for a longer period of time (˜40-fold greater) to achieve adequate signal to noise. In this way it was shown that Lys-CoA was still selective for p300 inhibition and H3-CoA-20 was still selective for PCAF blockade (using 20 μM Lys-CoA, greater than 90% p300 inhibition was achieved while less than 10% PCAF inhibition occurred; using 15 μM H3-CoA-20, greater than 90% PCAF inhibition was observed with less than 10% p300 inhibition detected, data not shown). Experiments with mixtures of PCAF and p300 and nucleosome substrate showed the same pattern of histone acetylation in the presence of inhibitors as observed for the free histone substrates (compare FIG. 3 A and 3 B). Thus it can be concluded the p300 and PCAF act independently in histone acetylation of nucleosomes as substrates. This is noteworthy since higher concentrations of HATs were used in the nucleosome experiments, which would be expected to encourage p300-PCAF interaction.
An important application of selective HAT inhibitors is to use them as tools in studies of transcriptional regulation. Given the limited ability of CoA conjugates to penetrate cell membranes (Robishaw and Neely, 1985), it was advantageous to evaluate these compounds in an in vitro chromatin-based transcription system. In this regard, we exploited a recently developed in vitro chromatin-transcription system that appears to require the HAT activity of full length p300 for the function of transcriptional activators (data not shown). The strategy designed for these experiments is outlined in FIG. 4 A.
The chromatin template was reconstituted by incubation of purified proteins (HeLa core histones, NAP1 and rh TopoI) with a 5.4 kb plasmid (p20855G5MLC2AT) that contains a 690 bp promoter region (5 Gal4 binding sites and the adenovirus major late promoter with a G-less cassette) flanked on both sides by the 5 nucleosome positioning sequence from the sea urchin 55 rRNA gene (Cote et al., 1995). Assembled chromatin was structurally characterized by supercoiling and micrococcal nuclease (MNase) assay (data not shown).
The chromatin template was nearly completely inert even in the presence of Gal-VP16 activator (FIG. 4B, lane 7). In contrast, an equimolar amount of the corresponding DNA template showed a high level of activator-dependent transcription that was 15-fold above the basal transcription (FIG. 4B, lanes 1 vs 2) and independent of the presence of p300 and/or acetyl-CoA (FIG. 4B, lane 2 vs 3-5). Addition of p300 along with Gal-VP16 activator had a negligible effect in activating transcription from the chromatin template (FIG. 4C, lane 8). However, addition of 1.5 μM acetyl-CoA along with p300 and Gal-VP16 activator increased transcription ˜10-fold compared to the reaction without acetyl-CoA addition (compare FIG. 4C, lanes 8 vs 9), suggesting a role for the p300 HAT activity in the observed transcription activation.
Preincubation of p300 with the p300 selective HAT inhibitor Lys-CoA (10 μM) completely abolished the p300 and acetyl-CoA dependent transcription activation from the chromatin template (FIG. 4C, lanes 10 vs 9). Similar pretreatment of p30 with the PCAF selective inhibitor, H3-20-CoA (10 μM) marginally inhibited (˜30%) the p300 HAT activity dependent transcription (FIG. 4C, lanes 9 vs 11) consistent with the expected specificity of the inhibitors. As a control, it was shown that the effect of these two inhibitors on naked DNA transcription was minimal, Lys-CoA inhibited naked DNA transcription only 15-20% (average of 4 independent experiments) and H3-20-CoA did not affect transcription at all (FIG. 4C, lanes 2 vs 3 and 4). These data establish directly the role of p300 HAT activity in this transcriptional system.
Further studies showed that baculovirus expressed full length PCAF had no effect on activator dependent transcription from the chromatin template in either the presence or absence of p300 under the conditions we have tested (data not shown). It was a formal possibility that PCAF could be recruited to the promoter in the presence of p300, and provide a redundant HAT function that did not further increase transcription. However, this possibility was ruled out by showing that Lys-CoA abolished transcriptional activation in the presence of p300-PCAF mixtures just as it did with p300 alone (data not shown).
In summary, these studies report the design, synthesis, and evaluation of the first selective HAT inhibitors. These HAT inhibitors were used to quantify the contributions of the interacting HATs p300 and PCAF in histone acetylation and revealed an additive but non-synergistic interaction between the PCAF and p300 HAT activities in the systems investigated. Furthermore, the p300-selective inhibitor, Lys-CoA, showed a specific inhibition of p300 and acetyl-CoA dependent transcription from a chromatin template, directly demonstrating the importance of the p300 HAT activity in transcriptional enhancement in an in vitro system. Applications employing selective HAT inhibitors as biological tools in a variety of contexts can now be pursued.
Experimental procedures
Lys-CoA synthesis
Synthesis of Lys-CoA was carried out as follows: N-acetyl-lysine-amide hydrochloride (Ac-Lys-NH 2 , 50 mg, 224 mmol), bromoacetic acid (31 mg, 224 mmol), 1-[3-(dimethylamino)propyl]-3-ethylcarbodiimide hydrochloride (EDC, 43 mg, 224 mmol), and triethylamine (31.1 ml, 224 mmol) were dissolved in 4 mL N,N-dimethylformamide (DMF). After stirring under nitrogen at room temperature (12 h), more bromoacetic acid (31 mg, 224 mmol) and EDC (43 mg, 224 mmol) were added to the reaction. After an additional 4 h, the mixture was concentrated in vacuo. The residue was dissolved in 4 mL aqueous 1 M triethylammonium bicarbonate (pH 8.0)/4 mL methanol, CoASH (129 mg, 155 mmol) was added, and the reaction was stirred overnight under nitrogen for a total of 15 hours, Lys-CoA was purified from this solution by preparative reverse phase C-18 HPLC. The compound was eluted (t R =30 min, λ=260 nm) at a constant flow rate of 10 mL/min with 100% aqueous 50 mM KH 2 PO 4 (pH 4.5) for 5 minutes, followed by a linear gradient to 40% methanol over 35 minutes, Lys-CoA was desalted by preparative C-18 HPLC at a constant flow rate of 10 mL/min, eluting with 100% H 2 O (0.05% TFA) for 30 min, followed by a linear gradient to 100% methanol over 5 min. then 100% methanol for 20 min to elute the compound (t R =41 min). The methanol was removed on a rotary evaporator and the compound was dissolved in H 2 O and lyophilized for 48 hr. The compound (51 mg, 23% yield) appeared >95% pure by analytical reversed phase C-18 HPLC. 1 H NMR (400 MHz, D 2 O), and electrospray mass spectrometry, which showed data in full accord with the reported structure.
Peptide CoA Conjugate Syntheses
Peptide CoA conjugates and other peptides (H3-CoA-7, H4-CoA-7, H3-CoA-20, H4-CoA-20, H3-20, H4-20) were synthesized using the solid phase fluorenylmethoxycarbonyl peptide synthesis strategy on a Rainin PS-3 machine. The N-terminal residues were used in the α-amino acetylated forms and the C-terminal residues were the free acids for the 20 aa peptides (obtained with Wang resin) and the carboxamides for the 7 aa peptides (obtained with Rink amide resin). Note that lysine residues that were not conjugated with CoA were orthogonally protected with Dde (dimethyldioxocyclohexylidene) ε-NH 2 group) whereas the others were protected with tert-butoxycarbonyl groups. Peptides were cleaved from the resin and deblocked with trifluoroacetic acid in reagent K which left the Dde group intact and then reacted as described above with excess bromoacetic acid (˜4 equivalents) and CoASH (˜5 equivalents), followed by Dde removal via hydrazinolysis (3% aqueous hydrazine at room temperature, 2-3 h). For standard peptides (H3-20 and H4-20), Dde groups were removed without carrying out the CoA coupling steps. Peptides were purified by preparative reversed phase C-18 HPLC (H 2 O:CH 3 CN: 0.5% trifluoroacetic acid). Peptides appeared >95% pure using analytical reversed phase C-18 HPLC and showed the predicted molecular mass using electrospray mass spectrometry.
HAT Activity Inhibition Assays
Full length PCAF and p300 proteins were prepared and purified according to previously described methods (Schiltz et al., 1999). HAT inhibition assay procedures were adapted from previously described methods (gryzko et al., 1996; Yang et al., 1996; Schiltz et al., 1999). Briefly, substrate concentrations were 10 μM acetyl-CoA (NEN, 14 C, 0.02 μCi/μL), 33 μg/mL mixed histones (Boehringer); buffer conditions-50 mM Tris-HCl (pH 8), 10 mM sodium butyrate 1 mM phenylmethyl sulfonyl fluoride, 1 mM dithiothreitol, 0.1 mM N,N,N′,N′-ethylenediamine tetraacetic acid and 10% v/v glycerol. Reactions employed purified recombinant p300 and PCAF (Schiltz et al., 1999) at concentrations of 6 nM and 27 nM, respectively. A range of at least 5 inhibitor concentrations were used. Assays were carried out in 0.5 mL plastic tubes at 30° C. and the reaction volumes were 30 μL. Reactions were initiated with the radioactive acetyl-CoA (4 μL) after allowing the enzyme/buffer/histone/inhibitor mixture to equilibrate at 30° C. for 10 min, and reactions quenched after 1 min with 7.5 μL 5×SDS gel load. Mixtures were run out on 15% SDSPAGE visualized with Coomassie blue, dried, and radioactivity quantified by phosphorimage analysis (Molecular Dynamics). In all cases, background acetylation (in the absence of enzyme) was subtracted from the total signal. All assays were performed at least twice and duplicates generally agreed within 20%. IC 50 values were estimated from bar graph plots (see FIG. 2 for an example) and estimated standard errors on these values are ±20%. For nucleosomes (Cote et al., 1995), enzyme concentrations were 24 nM for p300 and 432 nM for PCAF and reactions were allowed to proceed for 40 min before quenching (nucleosome concentrations had approximately equal amount of protein visualized by SDSPAGE as the mixed histone reactions).
Transcription studies
Native HeLa nucleosome was prepared as described elsewhere (Cote et al., 1995). Human core histones were purified as described elsewhere (Kunda et a, 1998). Recombinant His 6 -tagged nucleosome assembly protein 1 (NAP1) and transcription activator Gal4-VP16 were expressed in E. coli and purified with nitrilloacetic acid-agarose (Qiagen) as specified by the manufacturer. Baculovirus expressed recombinant human topoisomerase I (rh TopoI) and full length p300 were purified as described previously (Wang and Roeder, 1996; Kraus and Kadonaga, 1998). Chromatin template for transcription studies were assembled on a ˜5.4 kb plasmid (p2085S G5MLC2AT) with purified human core histones, rh TpopI, and NAP1 as described (T. K. K. et al., manuscript in preparation). Prior to use in the transcription experiment, assembled, chromatin was subjected to supercoiling and Mnase assay. In vitro transcription assays were carried out in 50 μL reaction mixtures containing either 28 ng of DNA or an equivalent amount of chromatin.
Summary
Here we described the design, synthesis, and application of peptide CoA conjugates as selective HAT inhibitors for the transcription factors p300 and PCAF. Two inhibitors (Lys-CoA for p300, H3-CoA-20 for PCAF) were found to be potent (IC 50 ˜0.5 μM) and selective (˜200-fold) in blocking p300 and PCAF HAT activity. These inhibitors were used to show quantitatively that PCAF and p300 display additive but not synergistic HAT activity when present in mixtures. Lys-CoA was used to directly demonstrate the importance of p300 HAT activity in enhancing chromatin template mediated transcription in vitro.
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Wybenga-Groot, L. E., Draker, K.-a., Wright, G. D., and Berghuis, A. M. (1999) Crystal structure of an aminoglycoside 6′-N-acetyltransferase defining the GCN5-related N-acetyltransferase superfamily fold. Structure 7, 497-507.
Yang, X.-J., Ogryzko, V. V., Nishikawa, J., Howard, B. H., and Nakatani, Y. (1996) A p300/CBP-associated factor that competes with the adenoviral oncoprotein E1A. Nature 382, 319-324.
Figure Legends
1) FIG. 1 . Design and Synthesis of Peptide CoA Conjugates. (A) General scheme for CoA coupling to the lysine ε-NH2 groups. (B) Peptide CoA conjugates evaluated for HAT inhibition. See Experimental Procedures for synthetic details.
2) FIG. 2 . Evaluation of Lys-CoA as a HAT Inhibitor. (A) Autoradiographic analysis of p300 HAT inhibition by Lys-CoA. Lanes 1-5 employed 0, 0.1, 0.5, 2.5, and 10 μM concentrations of Lys-CoA. Imaged bands are histones H4 (top) and H3 (bottom). See Experimental Procedures for details. (B) Bar graph analysis of p300 HAT Inhibition by Lys-CoA at the concentrations indicated, quantitated using Phosphorimage analysis (Molecular Dynamics). HAT activity is normalized to 100% for no added inhibitor. (C) Bar graph analysis of PCAF HAT Inhibition by Lys-CoA at the concentration indicated, quantitated using Phosphorimage analysis (Molecular Dynamics). HAT activity is normalized to 100% for no added inhibitor. Standard error was found to be ±20% for duplicate runs.
3) FIG. 3 . Assessment of p300 and PCAF HAT Activities in p300/PCAF Mixtures. (A) p300 and PCAF HAT activities with mixed histones as substrates. Bar 1, PCAF alone without inhibitors; Bar 2, p300 alone without inhibitors; Bar 3; PCAF+p300 without inhibitors; Bar 4, PCAF+p300+Lys-CoA (30 μM); Bar 5, PCAF+p300+H3-CoA-20 (20 μM); Bar 6, PCAF+p300+Lys-CoA (30 μM)+H3-CoA-20 (30 μM). Activities were normalized to 100% for Bar 3. Standard error was found to be ±20% for duplicate runs. In a separate experiment done under identical conditions with the individual enzymes, it was shown that Lys-CoA (20 μM) and H3-CoA-20 (15 μM) blocked p300 and PCAF HAT activity greater than 90%, respectively, and showed less than 10% inhibition with PCAF and p300, respectively (data not shown). See Experimental Procedures for details. (B) p300 and PCAF HAT activities with nucleosomes as substrates. Bar 1, PCAF alone without inhibitors; Bar 2, p300 alone without inhibitors; Bar 3; PCAF+p300 without inhibitors; Bar 4, PCAF+p300+Lys-CoA (20 μM); Bar 5, PCAF+300+H3-CoA-20 (15 μM); Bar 6, PCAF+p300+Lys-CoA (20 μM)+H3-CoA-20 (15 μM). Activities were normalized to 100% for Bar 3. Standard error was found to be ±20% for duplicate runs. In a separate experiment done under identical conditions with the individual enzymes, it was shown that Lys-CoA (20 μM) and H3-CoA-20 (15 μM) blocked p300 and PCAF nucleosome acetylation activity greater than 90%, respectively, and showed less than 10% inhibition with PCAF and p300, respectively (data now shown) See Experimental Procedures for details.
4) FIG. 4 . Lys-CoA inhibits p300 HAT activity dependent transcription activation. (A) Outline of the in vitro transcription protocol. (B) and (C) Transcription form naked DNA and chromatin templates. DNA (28 ng) and freshly assembled chromatin templates (with an equivalent amount of DNA) were incubated with or without activator, Gal4-VP16 (30 ng) for 20 min at 30°, 25 ng of baculovirus expressed, highly purified p300 (full length) and 1.5 μM of acetyl-CoA were added as indicated. Following the addition of nuclear extract (source of general transcription factors) and NTPs, transcription reactions were incubated and processed as described (T. K. K. et al., manuscript in preparation). Before adding it to the reaction, p300 was incubated (4° C., 20 min) with or without inhibitors; without inhibitor (pane C, lanes 2 and 9), 10 μM Lys-CoA (panel C, lanes 3 and lane 10) or H3-CoA-20 (Panel C, lanes 4 and 11).
TABLE 1
Compound
IC 50 with p300 (μM)
IC 50 with PCAF (μM)
CoASH
200
>20
H3-20
—
>20
H3-CoA-7
>30
>20
H3-CoA-20
200
0.3
H4-CoA-20
>10
>10
Lys-CoA
0.5
200
Table 1 provides IC 50 values for synthetic compounds with CoASH. Substrate concentrations were: [acetyl-CoA]=10 M, [mixed histones]=33 μg/mL. Assays were performed as described in Experimental Procedures. The IC 50 values are identified as the concentrations of compound necessary to cause 50% inhibition of the acetyltransferase reaction. The values written as ‘>10 μM’ or ‘>20 μM’ indicate that less than 50% inhibition was observed at these inhibitor concentrations (the upper limit used in the particular assay). Standard errors on all values are estimated to be ±20%.
14
1
8
PRT
Artificial Sequence
Description of Artificial Sequence PART OF
SYNTHETIC MOLECULES THAT ACT AS ENZYME INHIBITORS
1
Thr Ala Arg Lys Ser Thr Gly Gly
1 5
2
5
PRT
Artificial Sequence
Description of Artificial Sequence PART OF
SYNTHETIC MOLECULES THAT ACT AS ENZYME INHIBITORS
2
Ala Pro Arg Lys Gln
1 5
3
13
PRT
Artificial Sequence
Description of Artificial Sequence PART OF
SYNTHETIC MOLECULES THAT ACT AS ENZYME INHIBITORS
3
Ala Arg Thr Thr Lys Gln Thr Ala Arg Lys Ser Thr Gly
1 5 10
4
6
PRT
Artificial Sequence
Description of Artificial Sequence PART OF
SYNTHETIC MOLECULES THAT ACT AS ENZYME INHIBITORS
4
Ala Pro Arg Lys Gln Leu
1 5
5
4
PRT
Artificial Sequence
Description of Artificial Sequence PART OF
SYNTHETIC MOLECULES THAT ACT AS ENZYME INHIBITORS
5
Ala Pro Arg Lys
1
6
4
PRT
Artificial Sequence
Description of Artificial Sequence PART OF
SYNTHETIC MOLECULES THAT ACT AS ENZYME INHIBITORS
6
Gly Leu Gly Lys
1
7
12
PRT
Artificial Sequence
Description of Artificial Sequence PART OF
SYNTHETIC MOLECULES THAT ACT AS ENZYME INHIBITORS
7
Ala Arg Thr Lys Gln Thr Ala Arg Lys Ser Thr Gly
1 5 10
8
13
PRT
Artificial Sequence
Description of Artificial Sequence PART OF
SYNTHETIC MOLECULES THAT ACT AS ENZYME INHIBITORS
8
Ala Arg Thr Lys Gln Thr Ala Arg Lys Ser Thr Gly Gly
1 5 10
9
7
PRT
Artificial Sequence
Description of Artificial Sequence PART OF
SYNTHETIC MOLECULES THAT ACT AS ENZYME INHIBITORS
9
Ser Gly Arg Gly Lys Gly Gly
1 5
10
12
PRT
Artificial Sequence
Description of Artificial Sequence PART OF
SYNTHETIC MOLECULES THAT ACT AS ENZYME INHIBITORS
10
Gly Leu Gly Lys Gly Gly Ala Lys Arg Asn Arg Ala
1 5 10
11
7
PRT
Artificial Sequence
Description of Artificial Sequence SYNTHETIC
MOLECULE THAT ACT AS ENZYME INHIBITOR
11
Gly Gly Lys Ala Pro Arg Lys
1 5
12
7
PRT
Artificial Sequence
Description of Artificial Sequence SYNTHETIC
MOLECULE THAT ACT AS ENZYME INHIBITOR
12
Gly Gly Lys Gly Leu Gly Lys
1 5
13
20
PRT
Artificial Sequence
Description of Artificial Sequence SYNTHETIC
MOLECULE THAT ACT AS ENZYME INHIBITOR
13
Ala Arg Thr Lys Gln Thr Ala Arg Lys Ser Thr Gly Gly Lys Ala Pro
1 5 10 15
Arg Lys Gln Leu
20
14
20
PRT
Artificial Sequence
Description of Artificial Sequence SYNTHETIC
MOLECULE THAT ACT AS ENZYME INHIBITOR
14
Ser Gly Arg Gly Lys Gly Gly Lys Gly Leu Gly Lys Gly Gly Ala Lys
1 5 10 15
Arg Asn Arg Ala
20 | Histone acetyltransferase inhibitors, especially those that are differentiate between p300 and PCAF histone acetyltransferase; also therapeutic processes comprising their administration to humans. | 52,028 |
RELATED APPLICATIONS
[0001] This application claims the benefit of U.S. Provisional Patent Application Ser. No. 61/406,414 filed Oct. 25, 2010, and is a continuation-in-part of U.S. patent application Ser. No. 13/069,292 filed Mar. 22, 2011 (which claims the benefit of U.S. Provisional Patent Application Ser. No. 61/316,070 filed Mar. 22, 2010), which is a continuation-in-part of U.S. patent application Ser. No. 12/911,445 filed Oct. 25, 2010 (now abandoned), which is a continuation of U.S. patent application Ser. No. 12/106,968 filed Apr. 21, 2008 (now U.S. Pat. No. 7,822,896 and which claims the benefit of U.S. Provisional Application Ser. No. 60/950,040 filed Jul. 16, 2007), which is a continuation-in-part of U.S. patent application Ser. No. 11/801,127 filed May 7, 2007 (now abandoned), which is a continuation of U.S. patent application Ser. No. 11/296,134 filed Dec. 6, 2005 (now U.S. Pat. No. 7,216,191), which is a continuation-in-part of U.S. patent application Ser. No. 11/043,296 filed Jan. 25, 2005 (now abandoned), which is a continuation-in-part of U.S. patent application Ser. No. 10/071,870 filed Feb. 8, 2002 (now U.S. Pat. No. 6,892,265 and which claims the benefit of U.S. Provisional Application Ser. No. 60/269,129 filed Feb. 14, 2001). The foregoing disclosures are incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to methods and apparatus for driving solenoids, and more particularly to a configurable connectorized apparatus for driving a solenoid coil.
BACKGROUND
[0003] Solenoids are widely used throughout the world. Thus solenoids actuate relays or contactors that apply power to the starter motor of most cars. Solenoids actuate the lock mechanism in most keyless door systems. Most automatic valves, whether pneumatic or fluidic, employ solenoids to actuate or pilot the valve. Solenoids are found in factories, buildings, cars and homes.
[0004] FIG. 1 depicts a generic solenoid 10 showing its principal constituent parts. The two leadwires, 2 , convey electrical current to the solenoid coil 3 which generates a magnetic field. The magnetic circuit of said solenoid 10 includes the metal case 4 and the air gap 6 . The armature 5 is influenced by the magnetic field and a force will attempt to move or hold the armature 5 in the direction of the hardstop 8 . When said armature 5 contacts and remains in contact with said hardstop 8 , it is said to be sealed. Various features are often added to said armature 5 such as the hole 7 in order to attach a mechanism to the armature 5 and thereby complete the mechanical linkage to the solenoid mechanism. Not shown is the return mechanism, such as a spring, which tends to return said solenoid 10 to its open position when electrical current is removed from said solenoid 10 .
[0005] Solenoids transduce the flow of electrical current into motion via force on the moving portion of the solenoid called the armature. The armature of a solenoid may be connected to various mechanisms, thus in a relay, the armature motion opens or closes electrical contacts whereas in a solenoid-operated valve, the armature is often directly connected to one side of a valve seal. In larger valves, the solenoid operates a smaller so-called pilot valve that employs some fluidic or pneumatic amplification, but the basic operation of the valve is initiated by the solenoid action.
[0006] Therefore, solenoids are essential components in a wide range of mechanisms that perform among other things, electrical switching, latching, braking, clamping, valving, diverting or connecting.
[0007] The most common method of actuating solenoids involves applying a constant voltage to the coil, whether AC or DC. The voltage causes a current to flow in the coil and a consequent magnetic field is generated which puts force on the solenoid armature and moves the mechanism to which the solenoid is attached. However, as described in detail below, there are significant challenges associated with driving solenoids in an energy efficient manner with circuitry that does not itself create further problems.
[0008] FIGS. 2-4 provide examples of circuits used for driving solenoids. FIG. 2 depicts a common prior art transistor solenoid drive circuit including transistor 11 which is capable of conducting electrical current in response to a signal on its input. Said electrical current will flow through solenoid 10 . When said transistor 11 is caused to stop conducting in response to a signal on its input, a flyback diode 14 conducts electrical current in order to prevent the inductive component of said solenoid 10 from increasing the voltage seen by said transistor 11 and possibly destroying said transistor 11 . When the energy in said solenoid 10 has been exhausted by the recirculation process, said current ceases and said solenoid 10 is thus de-energized.
[0009] FIG. 3 depicts a solenoid driver integrated circuit 12 such as is commercially available from a number of manufacturers and employing pulse width modulation (PWM) of the supply voltage in order to reduce the holding current to the solenoid 10 . Connected to said solenoid driver 12 is said solenoid 10 as well as two of the commonly required external components, a flyback diode 14 and a series-connected diode 13 intended to both prevent damage to said driver integrated circuit 12 and to somewhat reduce electrical radiation from the PWM switching transients. Said solenoid driver integrated circuit 12 is fixed configuration and cannot be reconfigured for other purposes such as measuring or producing voltages or currents other than required for the narrow solenoid drive task at hand.
[0010] FIG. 4 depicts a typical prior art fixed configuration sinking output module 17 capable of driving solenoid 10 . As is typical for the prior art, said output module 17 does not provide power to drive said solenoid 10 but instead relies upon connecting and disconnecting power provided by external device power supply 18 . In addition, as is customary for said fixed-configuration output modules 17 , terminal blocks 19 are employed to effect the wiring to said solenoid 10 . In addition, as is customary for said output modules, a protective flyback diode 14 is installed to reduce voltages produced by said solenoid 10 during the de-energization process.
[0011] As is widely known to those skilled in the art of solenoid-driven mechanism design, there is a delicate balance between providing sufficient solenoid force at a desired distance of travel and generating excessive energy consumption and heating in the solenoid coil. The amount of electrical current required to move the solenoid to its closed position is high compared to the electrical current required to keep the solenoid closed—or sealed as is the term of art. Thus a solenoid that is to remain sealed for a long period of time tends to become hot and consume a large amount of energy compared to what is needed just to hold the solenoid sealed. The delicate balance for the solenoid-driven mechanism designer is to build a solenoid that will reliably move a given distance to the sealed position while at the same time not consuming excessive electrical power or overheating despite constant application of power to the solenoid coil.
[0012] This basic design challenge of the solenoid underscores the problem that is to be solved by this invention, and therefore a more detailed description of the cause of this design challenge is justified in order to explain the merits of this invention.
[0013] Whereas the solenoid transduces the flow of electrical current to force on the armature, said force is not a constant function of electrical current. When the solenoid is sealed, there is essentially no air gap in the magnetic circuit, thus the magnetic flux is relatively high at a given electrical current. However, when the solenoid is fully open, there exists an air gap in the magnetic circuit that significantly increases the electrical reluctance of the circuit, said reluctance being the ratio of magnetomotive force (MMF) to magnetic flux developed. Thus at said given electrical current, the force on the fully open armature can be significantly lower than when the armature is in the sealed position. In order to move the armature reliably, therefore, it is necessary to supply more electrical current than is required when the solenoid is sealed. To make matters worse, the requirement for high current to seal the solenoid only lasts for a fraction of a second whereas the solenoid is often left in its conducting, sealed state indefinitely. Energy is being wasted.
[0014] Those skilled in the art long ago realized that, for a given solenoid current, the force on the armature increases as the armature moves closer to its sealed or closed position because reluctance decreases with the shorter air gap. These same persons reasoned that by varying the current or voltage to the solenoid, they could provide an initially higher force to seal the solenoid and subsequently reduce the current or voltage in order to hold the solenoid sealed because the force exerted upon a sealed solenoid armature is much higher than the force on an open solenoid given the same electrical current or voltage. By employing this strategy of varying the current or voltage, it is possible to reduce the heating of the solenoid coil while providing the required high force to close the solenoid.
[0015] In U.S. Pat. No. 7,262,950 B2 (“Suzuki”), Suzuki teaches that building a current control circuit can allow cutting back the current to the relay coil after the relay has closed. Unfortunately, the circuit of Suzuki requires that a series-wired transistor throttle the current to the relay coil thus creating heat and reducing the possible energy savings considerably. Thus Suzuki's invention does somewhat reduce solenoid heating but by moving some of the heat generation to a transistor. For example, if Suzuki reduced the holding solenoid current to ½ of the initial pull-in current, then the system of Suzuki would see solenoid energy use go down to ¼ of the previous level. Unfortunately, another ¼ of said energy is burned up in ohmic losses in the transistor. In addition, Suzuki does not mention a strategy for dealing with the effect of the relay coil inductance during relay turn-off. It is well understood in the art that employing a transistor to remove power from an inductor will result in a large voltage swing that in general must be mitigated by inserting a path for current to flow thus avoiding a dangerous increase in circuit voltage. Generally, a diode is employed that will allow the relay coil current to circulate during turn-off.
[0016] Others have attempted to avoid wasting half of the energy reduction. Others have reasoned that employing pulse width modulation (PWM) of the solenoid voltage could reduce the losses in the transistor via well-understood power switching technology in which the transistor is rapidly turned on and off, largely avoiding its linear region. This strategy works well for inductive circuits wherein little current initially flows during the closing of the transistor. Fortunately, a solenoid is highly inductive, thus PWM works well. Unfortunately, however, PWM can easily generate disruptive electrical radiation unless special care is taken. In an industrial control system application it is almost unthinkable to place restrictions on the user of a solenoid.
[0017] Then too, a class of integrated circuits, such as Texas Instruments DRV102 PWM Valve/Solenoid Driver, has aimed to produce a fixed and dedicated electrical circuit capable of initially driving the solenoid with full voltage and consequently full current and subsequently reducing said current by performing PWM of the power signal to the solenoid. Unfortunately, said integrated circuits can produce undesirable electrical interference as described earlier. For example, an application note for the Texas Instruments DRV102 states, “The PWM switching voltages and currents can cause electromagnetic radiation.” The note further suggests that determining the location of noise reducing components “may defy logic”, i.e. may be difficult to predict and require repetitive empirical testing. In addition, such integrated circuits usually require the addition of a number of external components and are fixed configuration: the connector to which the solenoid is attached can only drive a solenoid. The present invention as explained below provides additional applications and flexibility that is not available using these prior art devices.
[0018] The prior art has not adequately addressed a significant design challenge in solenoid driving: how to determine if a solenoid is sealed. A solenoid can fail to reach or stay at its closed or sealed position upon the application of electrical current for a number of reasons. The solenoid may be jammed and unable to initially move in either direction. The solenoid coil may be open or not electrically continuous and therefore incapable of generating the required magnetic field. The solenoid coil may be shorted. The solenoid may be exposed to vibration that puts a sufficient force on the solenoid to unseal it. Or, there could be a momentary loss of electrical current that results in the solenoid holding force being reduced briefly. Or, the current applied to the solenoid coil might be slightly less than required to reliably hold the solenoid armature sealed under all physical variations such as ambient temperature. The prior art only teaches a single solution to this dilemma of determining the solenoid state, and that is to cause the solenoid to close an electrical connection when it is sealed. FIG. 5 depicts the prior art apparatus for determining the state of the solenoid, whether sealed or open. In this prior art system, the controller 90 commands a solenoid coil 91 to close. After the solenoid 91 has been given sufficient time to seal, the controller 90 then senses the state of the auxiliary contact 92 which is mechanically linked to the solenoid mechanism. Based upon the state of said auxiliary contact 92 , said controller 90 can deduce the state of the solenoid 91 . However, if the solenoid 10 is not a relay, then said solenoid 10 must be mechanically connected to said auxiliary contact 92 , such connection being problematic and costly. Even in the case where the solenoid is part of a relay, this strategy requires using one set of contacts for this monitoring process. Additional electrical circuits are required to monitor this extra contact, and for systems employing reduced holding current, the actuation sequence must be repeated. In the case where the solenoid is not a part of a relay, then a set of contacts must be added to the solenoid mechanism. This requirement is prohibitive except for the most critical solenoid systems.
SUMMARY OF THE INVENTION
[0019] The present invention provides a configurable connectorized method and apparatus for driving a solenoid coil, capable of providing a sufficiently high force to move the solenoid from its fully open position to its sealed position. It can also reduce the energy consumed and the heating of the solenoid coil when the solenoid is sealed. The present invention reduces the energy without continuous losses from a series throttling transistor or resistor. The invention facilitates detection of a solenoid coil which is open or shorted, and can reduce the current on a solenoid for which the armature is jammed in order to reduce the consequential overheating of the coil. The present invention eliminates the requirement to use PWM as the drive method, and handles coil turn-off behavior without the need for additional components such as diodes. The present invention simplifies connections to one or more relays or solenoids without the requirement for external power supplies. The present invention allows determination of whether a solenoid is sealed without the need for auxiliary electrical contacts, and can use information about the solenoid unsealed state to essentially instantaneously increase the force on the solenoid armature to cause the armature to return to its sealed position before the armature has moved significantly.
[0020] The present invention extends the teachings of U.S. Pat. Nos. 6,892,265, 7,216,191 and 7,822,896 and U.S. patent application Ser. No. 13/069,292, published as Patent Appl. Publ. No. US 2011 / 0231176 . In the previous inventions, a configurable connectorized system is described in which any connector pin of such a system may be configured for a wide variety of electrical functions, such as measuring a voltage, producing a voltage, measuring a current, producing a current, producing various power levels or even handling frequency information such as serial communication data.
[0021] A single version product built using these teachings has solved numerous industrial controls problems. When compared with traditional industrial control input/output modules, the configurable, connectorized input/output module dramatically reduces the number of additional components required such as power supplies and terminal blocks. The configurable, connectorized input/output system eliminates the need for many different fixed-configuration modules by virtue of its ability to change the electrical configuration of its connector pins.
[0022] The present invention enables the pin configuration of the input/output module to be changed during normal operation, thus if a solenoid is connected between two such pins, the voltage across the solenoid may be changed without any added components or without the required use of PWM. Because the present invention enables the pin configuration to be changed from one power supply to another or varying the voltage level of any said multiple power supplies, the invention allows high efficiency power supplies to be used. Therefore, no throttling or PWM is required to reduce the voltage across the solenoid, although nothing precludes the use of PWM in the present invention should it, for some reason, be determined to be beneficial. In addition, the present invention also provides two ways to handle the inductive current at turn-off. First, the configurable connectorized module can throttle the current gradually while holding the coil voltage within an acceptable level. Second, the first of one of the solenoid's two pins may be again reconfigured to the same voltage as the second pin thus connecting both sides of the solenoid coil to the same power supply, either high side or low side. In both ways, the effect of the inductance of the coil during circuit turnoff is addressed, and no additional components are required to provide for safe circuit operation.
[0023] In addition, because the present invention provides for connecting other sensing and sourcing circuit elements to the connector pin, it is possible to determine whether the solenoid is sealed. Said determination is based upon the fact that the electrical inductance of the solenoid is inversely related to the electrical reluctance and said reluctance decreases as the solenoid air gap goes to zero. Said determination is achieved by imposing either a periodic or step change to voltage across the solenoid and measuring the resulting periodic or step change in current. Said resulting current is a function of solenoid inductance. Or, alternatively, said determination may be achieved by making either a step change or a periodic change to the current through the solenoid and measuring the resulting change in voltage, although the preferred embodiment is the former method of determination. Said determination includes whether the solenoid is sealed, opening or open. In addition, in the case where the solenoid becomes unintentionally unsealed, the method and apparatus of the present invention is capable of essentially simultaneously increasing the solenoid current to reseal the solenoid, thus preventing unintended opening of the solenoid. Said resealing can be effected without any additional apparatus than is found in the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 is a depiction of a generic solenoid showing its principal constituent parts.
[0025] FIG. 2 is a common prior art circuit apparatus for driving a solenoid coil, and in particular shows the required fly-back diode.
[0026] FIG. 3 is a common prior art circuit apparatus for driving a solenoid coil that uses pulse width modulation (PWM) and in particular shows the required series-wired diode as well as the additional fly-back diode.
[0027] FIG. 4 depicts a prior art circuit common to a programmable logic controller or industrial fixed-configuration output module.
[0028] FIG. 5 depicts the prior art apparatus for detecting the unsealed state of a solenoid.
[0029] FIG. 6 depicts the configurable apparatus of the present invention.
[0030] FIG. 7 depicts the connection of a relay or solenoid coil to a configurable connectorized module of the present invention.
[0031] FIGS. 8A , 8 B and 8 C depict the command, voltage and current wave forms, respectively, of the present invention when actively snubbing the decaying solenoid currents to zero.
[0032] FIGS. 9A , 9 B and 9 C depict the command, voltage and current wave forms, respectively, of the present invention when allowing decaying solenoid currents to flow to zero.
[0033] FIG. 10 depicts a model of the constituent resistive and inductive components of the solenoid for the purpose of describing the method and apparatus of the present invention for determining the unsealed state of a solenoid.
[0034] FIGS. 11A , 11 B, 11 C and 11 D depict the voltage and current waveforms, employed to measure the inductance of the solenoid and thereby determine the unsealed state of said solenoid, of the present invention.
[0035] FIGS. 12A and 12B depict voltage and current waveforms for an alternative method of the present invention for solenoid state determination.
[0036] FIG. 13 is an example of an ASIC configured as a pin driver interface apparatus, according to some embodiments of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0037] FIG. 6 depicts a functional block diagram of the configurable connectorized input/output module 15 of the present invention. Included inside said module 15 of the preferred embodiment is a microprocessor 80 which is capable of directing any of a plurality of signals to one or more pins 16 which are subsequently to be connected to various sensors and actuators such as solenoid, but by no means limited to solenoids. In particular, said configurable connectorized input/output module 15 contains one or more power supplies 81 which may be routed in the same manner as other of the plurality of signals via switching means 82 such as R 5 or R 6 and connect to one or more connector pins 16 . When a solenoid is connected between two such pins 16 , the configurable connectorized input/output module 15 can produce one of a plurality of power levels to said solenoid thereby adjusting the current flowing through the solenoid without the need for PWM.
[0038] The configurable input/output module 15 may contain any number of interconnection apparatus 83 . Each interconnection apparatus 83 is connected to one device connector 16 and optionally through an internal cross point switch to another interconnection apparatus. (See FIG. 13 and related description.) FIG. 6 is highly stylized and is intended to convey the essence of the module of the present invention.
[0039] FIG. 7 depicts the configurable connectorized input/output module 15 of the present invention when connected to a solenoid 10 . In this configuration, said module 15 has been configured by the microprocessor 80 to route a plurality of power levels from power supplies 81 to pins 1 and 2 of said module 15 . Any of the 15 pins shown in FIG. 7 could have been configured for this function, unlike prior art fixed-configuration output modules. Unlike the prior art fixed-configuration output module, where an external device power supply was required, none is required by the present invention and none is shown in FIG. 7 . Also unlike the prior art fixed-configuration output module where a flyback diode is required to protect the output module, none is required by the present invention and thus none is shown. The configurable connectorized input/output module 15 of the present invention is thus able to cause one of a plurality of voltages to be applied to the connected solenoid 10 thus effecting the goals of the present invention.
[0040] FIGS. 8A , 8 B and 8 C depict the voltage and current waveforms resulting from the actuation of the solenoid 10 using a snubbing turnoff method and apparatus, and shown as Solenoid Drive Signal in FIG. 8A . There are nine phases to the voltage waveform which we will now describe. Each phase is numbered 21 through 29 in FIG. 8B .
[0041] In Phase 21 , the solenoid voltage is zero which is the idle state of the solenoid. The solenoid is unpowered and ready to be actuated.
[0042] In Phase 22 , in response to the solenoid drive signal becoming true, 30 , the configurable connectorized input/output module 15 connects the actuation-level voltage to the solenoid 10 . In this preferred embodiment, said activation-level voltage is 24V. In response to the imposed voltage, current in the solenoid coil rapidly increases, 40 , and the solenoid moves smartly because the imposed voltage is preferably higher than the sustainable steady state coil voltage. However by varying the duration of phase 23 , it is possible to control the solenoid actuation force.
[0043] In Phase 23 , the configurable connectorized input/output module 15 maintains the pull-in-level voltage on the solenoid coil and the coil current moves asymptotically to steady state, 41 . The length of the Phase 23 portion is sized such that said solenoid current may not reach steady state in order to control the solenoid actuation force. At the end of phase 41 , the solenoid is preferentially in its closed or sealed position.
[0044] In Phase 24 , the configurable connectorized input/output module 15 essentially simultaneously disconnects the actuation-level voltage from the solenoid and connects the sustain-level voltage to the solenoid. Alternatively, the voltage level of a single power supply can be varied to achieve the same goal. The sustain-level voltage is chosen to provide ample holding force for the solenoid, whereas said sustain-level voltage might not be sufficient to reliably pull in the solenoid under all conditions. Said sustain-level voltage can preferentially be adjusted by the microprocessor 80 . As Phase 24 begins, the solenoid coil current 42 begins to decrease in response to the lower applied voltage. Said solenoid coil current decreases to a steady state 43 after some time period which is a function of the solenoid electrical characteristics.
[0045] In Phase 25 , the sustain-level voltage is maintained on the solenoid in order to keep the solenoid sealed. Phase 25 is maintained as long as required by the control system. This time can range from milliseconds to months or longer.
[0046] In Phase 26 , the process is begun to remove power from the solenoid in response to the solenoid drive signal becoming false, 31 . The configurable solenoid drive circuit cannot simply open its drive transistors to the solenoid because the inductance of the solenoid coil—which makes rapid reduction in current infeasible—would cause the voltage at the configurable connectorized input/output module pin 16 to become very negative with respect to ground and likely damage or destroy the switching means 82 . If the solenoid coil is equipped with a so-called flyback diode, then said solenoid current is provided a path while the coil energy is dissipated. If, however, there is no flyback diode, then the coil voltage will cross zero volts and become negative. The configurable connectorized input/output module 15 of the present invention is therefore configured to begin to throttle the coil current and clamp the coil voltage to a value, which in the preferred embodiment is approximately −5V with respect to ground.
[0047] In Phase 27 , the throttling process continues until the voltage that the coil is capable of sourcing falls to less than the clamped voltage. During Phase 27 , the solenoid coil current 44 decreases linearly.
[0048] In Phase 28 , the configurable connectorized input/output module 15 stops actively throttling the solenoid coil current and instead provides a fixed transistor gate drive thus dissipating the remaining energy from the solenoid coil. The solenoid current, 45 , decays exponentially to zero during Phase 28 , and the solenoid coil returns to its idle state.
[0049] In Phase 29 , the solenoid coil is in the same state as it was in Phase 21 : the coil is quiescent, the solenoid is not engaged and the solenoid is again ready to be actuated. The solenoid coil current, 46 , is also zero.
[0050] With reference to FIGS. 6 & 7 , the interface apparatus 84 may be configured to connect one of a plurality of power supplies to the device connector 16 to which the solenoid 10 is connected. For example, switching means 82 can initially be caused to connect a 24VDC power supply to said device connector 16 in order to achieve the solenoid pull-in phase. Likewise, said interface apparatus 84 may then be caused to connect a 5VDC power supply to said device connector 16 in order to achieve the solenoid sustaining phase.
[0051] FIGS. 9A , 9 B and 9 C are very similar to FIGS. 8A , 8 B and 8 C with the exception that rather than throttling the solenoid current, the two pins of the configurable connectorized input/output module 15 which are connected to the solenoid 10 are set to the same voltage, either high-side or low-side. In so doing, the solenoid current flows through said module 15 until the solenoid current is exhausted. Thus phase 27 in FIG. 9B remains at zero volts, not −5 volts as in FIG. 8B . And the current in FIG. 9C decreases asymptotically to zero in phase 46 .
[0052] In the context of the present invention, determining the state of the solenoid, whether sealed, opening or fully open is achieved by measuring the inductance of the solenoid coil, since said inductance is inversely proportional to reluctance which is itself a function of the solenoid air gap: reluctance decreases as air gap decreases and then further decreases when the solenoid fully seals and the air gap is essentially eliminated. The present invention provides a number of methods and a number of apparatuses to measure said inductance. Two methods and two apparatuses will be described, but are intended to be for illustrative purposes only. Simpler or more appropriate methods using other features of the present invention are possible but this description is intended to convey the essence of the invention.
[0053] FIG. 10 depicts a common electrical circuit model used to describe the inductance measurement of the present invention. Specifically, the solenoid 10 has been broken down into two constituent parts. Its resistive component 95 is series-connected to its inductive component 96 . This model will facilitate the description of the inductance measurement system.
[0054] FIG. 11A depicts the DC voltage across a solenoid. Said voltage may be any appropriate value greater than or equal to zero volts. FIG. 11B depicts the resulting DC current given the applied voltage depicted in FIG. 11A , said resulting DC current being greater than or equal to zero. FIG. 11C depicts a sinusoidal voltage signal of suitable frequency imposed upon the DC voltage signal of FIG. 11A , said sinusoidal voltage being a sufficiently small percentage of the DC voltage as not to affect the operation of the solenoid but sufficiently large to generate a measurable current in said solenoid 10 . Said sinusoidal voltage signal is established by making small changes to the voltage setpoint of any of the multiple power supplies 81 connected to the configurable connectorized input/output module 15 of the present invention. Said sinusoidal voltage signal will cause a variation in the DC current signal of FIG. 11B that is also essentially sinusoidal. Said variation in the DC current signal is shown in FIG. 11D . The phase of the signal of FIG. 11D with respect to the sinusoidal voltage signal of FIG. 11C will be a function of the relative magnitudes of the two constituent elements depicted in FIG. 10 , the resistive 95 and inductive 96 components of said solenoid 10 . Specifically, if the resistive element 95 of FIG. 10 were to be large and the inductive component 96 of FIG. 10 were to be small, then the phase of the current signal of FIG. 11D with respect to the voltage signal of FIG. 11C will be small and closer to 0 degrees than 90 degrees. If, however, the resistive component 95 of FIG. 10 were to be small and the inductive component 96 of FIG. 10 were to be large, then the phase of the current signal of FIG. 11D with respect to the voltage signal of FIG. 11C will be large and closer to 90 degrees than 0 degrees. Using well known methods of signal processing wherein quadrature components of the current signal can be extracted, we can measure the inductive component of the solenoid 10 .
[0055] Alternative methods and apparatuses may be used for the inductance measurements, such as periodic square wave excitation rather than periodic sine wave excitation with similar results and perhaps a simpler and more effective embodiment. Furthermore, step changes in voltage or current and the subsequent measurement of the response in current or voltage can provide similar inductance measurements in an embodiment that may be more appropriate for the electronic circuits employed.
[0056] An alternative method for solenoid state determination relies upon observation of step responses rather than the phase and magnitude of response to periodic excitation. FIG. 12A depicts solenoid voltage for a typical energization and de-energization sequence, with state query pulses used to determine whether the solenoid is sealed. The magnitude or polarity, and the duration of these query pulses are designed to avoid altering the state of the solenoid. FIG. 12B depicts the solenoid current response to this sequence in FIG. 12A and its query pulses. The three voltages imposed across the relay in this method would, in a preferred embodiment, be the same levels used for energization, holding, and de-energization, although this is not a critical aspect of the present invention. This method will now be described in detail, in the order of events or phases in the depicted sequence.
[0057] Initially, the solenoid is de-energized, with zero current and voltage. In that state, query pulses of sufficiently small amplitude and duration can be applied to produce the current response 50 without moving the solenoid armature. By sampling said current response at its known peak, at the end of the query pulse, the solenoid inductance can be inferred with one sample provided the query pulse duration is short in comparison to the L/R time-constant of the solenoid in its sealed or unsealed state, or in between states. As described previously, this inductance indicates the solenoid state, an object of the invention.
[0058] At some time, the solenoid is energized, producing the current response 51 and one of the current responses 52 or 53 , depending upon whether the solenoid armature moves or not. Because the inductance can be measured for the de-energized state, and because responses 51 and 53 are both part of a simple, real exponential determined by that known inductance and the resistance known by other means, this non-moving pin response can be readily distinguished from the response pair 51 and 52 which exhibit markedly different trajectories. This distinction may be made by sampling the current at times along the response whose time-separation is short in comparison to the L/R time-constant, permitting a simple computation by microprocessor 80 to detect the trajectory departure 52 from the simple, real exponential, which departure indicates the desired motion of the solenoid armature. This method represents an improvement over an earlier invention, U.S. Pat. No. 3,946,285, which relies upon detection of the cusp at the end of response phase 52 , because it does not rely upon double differentiation or existence of the cusp which can be softened or eliminated if the solenoid armature is not abruptly stopped at the end of its energization travel.
[0059] After successful energization, the solenoid voltage is reduced to its holding level, producing current response 54 , eventually settling to the low-power holding current at the onset of current response 55 .
[0060] During energization, query pulses are applied at whatever rate is appropriate for the application, producing current response 55 . While this is similar to current response 50 , the current change relative to the step amplitude is smaller because of the much higher inductance of the solenoid in its sealed state. Again, as for current response 50 , a single sample at the response 55 peak can be used to infer solenoid inductance and hence its sealed or unsealed state. Because the inductance in the unsealed state is several times smaller than the sealed state inductance, the amplitude of the current response 55 , relative to its holding current baseline, readily distinguishes the solenoid states.
[0061] At some time, the solenoid is de-energized, producing the current response 56 and one of the current responses 57 or 58 , depending upon whether the solenoid armature moves or not. These conditions can be distinguished by the same criteria mentioned above for detection of successful energization, except to detect successful de-energization.
[0062] Finally, the de-energized starting state is reached, with query pulses producing current response 59 at whatever rate is appropriate for the application.
[0063] It should be noted that the query pulses indicate the solenoid armature position independently of whether armature motion is detected by distinguishing current trajectories. For many applications, the query pulses alone would suffice to detect solenoid failures. However, the motion detection provides an earlier indication of success or failure, during a time when the query pulses cannot be applied. Such earlier detection may be important in applications where other system actions should soon follow a solenoid state change, but only if that change occurs as commanded.
[0064] Said measurement of inductance can be pei formed constantly by the configurable, connectorized system of the present invention. Because the measurement does not affect operation of the solenoid, it is preferable that the measurement be first made when the solenoid is not energized with a DC voltage above zero. Said first measurement is then used as the baseline inductance of the solenoid.
[0065] While the solenoid is first commanded to seal by the action of the configurable connectorized input/output module 15 , said measurement of inductance continues to be made. When the solenoid is sealed, the sealed measured inductance will be higher than said first baseline measurement of inductance because of the previously described electrical characteristics of a solenoid. Said sealed measured inductance is stored by the microprocessor 80 of the configurable connectorized input/output module 15 and is subsequently used to determine the state of the solenoid, whether sealed, opening or open.
[0066] Said inductance measurement is continuously performed during the time that the solenoid is intended to remain sealed and during which time the solenoid voltage is at its lower holding level 25 . If, for any reason, said solenoid 10 becomes unsealed, its inductance will consequently decrease. Said inductance measurement will detect this decrease in inductance. Essentially simultaneously, the configurable connectorized input/output module 15 will increase the solenoid voltage to its pull-in value 23 in order to reseal the solenoid 10 . In so doing, the present invention can prevent the solenoid armature 5 from moving far enough to affect the mechanical state of the mechanism to which the solenoid 10 is connected. After the solenoid 10 is resealed, the configurable connectorized input/output module 15 may then again lower the applied solenoid voltage to the hold-in value 25 in order to again reduce the energy consumed by the solenoid 10 . The method and apparatus of the present invention may optionally slightly increase the applied solenoid voltage to slightly increase the solenoid holding force to compensate for the effect that led to the unsealing of the solenoid.
[0067] The snubbing turnoff method as described with reference to FIGS. 8A-8C above, the variations described with reference to FIGS. 9A-9C , the method for determining the state of a solenoid as described with reference to FIGS. 10 and 11 A- 11 D and variations thereof may all be implemented with the configurable, connectorized input/output module of the present invention and a computer program. The computer program may be stored in memory in the module and executed by the microprocessor in the module. Alternatively, the program may be stored externally to the module—in a control system for example—and instructions are sent to the microprocessor in the module for running the processes. In a further alternative, computer programs for some of the processes of the present invention may be stored in memory on the module, and some external to the module—in memory in the control system, for example. An example of a system controller 85 connected to the module 15 is shown in FIG. 7 . The connection between the system controller and the module may be a standard cable or a network connection (for example, Ethernet). The connection may be a backplane connector—for example, the module may be plugged into the backplane of a PLC or an embedded controller. The connection may also be a wireless connection. Without departing from the teaching of the present invention, a configurable, connectorized input/output module may: act as a so-called embedded controller; be a circuit board which is part of a larger system; or function as the system controller by itself.
[0068] The interface apparatus 84 , including interconnection apparatus 83 such as those illustrated in FIG. 6 , may be configured as an integrated circuit (IC). The IC is repeated within the I/O module 15 for each device connector 16 . Thus, if there are 25 device connectors 16 , then 25 ICs would be employed. The module 15 can contain any number of ICs, just as any module may contain any number of device connectors 16 . Another embodiment may employ a different IC architecture in which multiple device connectors 16 are handled in each IC or multiple ICs are used to handle one or more device connectors. The result of using an IC is a dramatic reduction in the size and cost of building a module 15 by virtue of the miniaturization afforded by modern semiconductor processes.
[0069] FIG. 13 is a block diagram of an integrated circuit capable of realizing the interface apparatus, 84 . The integrated circuit 198 has been specifically designed to serve the role of the interconnection apparatus, thus it may be referred to as an Application Specific Integrated Circuit (ASIC). This ASIC is specifically designed to provide the functionality of the interconnection apparatus 83 . At some point in the future, such an ASIC could become a standard product from an integrated circuit vendor. Therefore the term ASIC, as used herein, includes a standard integrated circuit designed to function as the interface apparatus. Furthermore, the term integrated circuit (IC), as it is used herein is intended to cover the following range of devices: ASICs, hybrid ICs, low temperature co-fired ceramic (LTCC) hybrid ICs, multi-chip modules (MCMs) and system in a package (SiP) devices. Hybrid ICs are miniaturized electronic circuits that provide the same functionality as a (monolithic) IC. MCMs comprise at least two ICs; the interface apparatus of the present invention may be realized by a MGM where the required functionalities are divided between multiple ICs. A SiP, also known as a Chip Stack MCM is a number of ICs enclosed in a single package or module. A SiP can be utilized in the current invention similarly to a MCM. In theory, programmable logic devices might be used to realize the interface apparatus of the present invention. However, currently available programmable logic devices, such as field programmable gate arrays (FPGAs), have a number of functional limitations that make their use undesirable—for example an FPGA cannot route power or ground to a given pin. Should FPGAs be extended to overcome these functional limitations then these improved FPGAs may be used as components to realize the interface apparatus 84 .
[0070] FIG. 13 depicts a block diagram of a pin driver ASIC 198 . When connected to the microprocessor 80 by a serial communication bus 206 such as an SPI interface, the microprocessor 80 of FIGS. 6 & 7 can command the ASIC 198 to perform the functions of the circuits of interconnection apparatus 83 . Although the circuitry of FIG. 13 appears different from the interconnection apparatus 83 , the ASIC 198 is capable of performing the same or similar required functions. Whereas FIG. 6 is a somewhat idealized diagram intended to convey the essence of the module of the invention, FIG. 13 contains more of the circuit elements that one would place inside an ASIC. Nonetheless, FIG. 13 implements all the circuit elements of FIG. 6 . For example, FIG. 6 shows a digital-to-analog converter (D/A or DAC) connectable to the device communication connector 16 . In FIG. 13 , the digital-to-analog converter 226 is connected to the output pin 208 via the switch 220 . The present invention also includes other circuit arrangements for an ASIC 198 for the same or similar purpose. Those skilled in the art will know how to design various such circuitry, and these are to be included in the present invention.
[0071] Exemplary features of the ASIC of FIG. 13 will now be briefly described. Power may be applied to pin 208 by closing high current switch 222 b and setting the supply selector 227 to any of the available power supply voltages such as 24-volts, 12-volts, 5-volts, ground or negative 12-volts. Said available power supply voltages provide the required pull-in and sustaining voltage levels to drive the solenoid.
[0072] The ASIC can measure the voltage on pin 208 by closing the low current switch 222 and reading the voltage converted by the analog-to-digital converter 216 .
[0073] The ASIC can measure the current supplied to pin 208 by way of the high current switch 222 b by use of the multiple programmable current limiters 224 which contain current measurement apparatuses. Said current measurement is used to determine the solenoid inductance as well as to determine whether said solenoid coil is shorted or open.
[0074] The periodic variation in voltage to the solenoid which is used to determine solenoid inductance is most easily accomplished by slightly varying the voltage of the plurality of power supplies 81 , said appropriate power supply being selected by supply selector 227 . The step change in voltage to the solenoid which is used to determine solenoid inductance is most easily accomplished by momentarily changing the supply selector 227 to increase or decrease the solenoid voltage in order to increase or decrease the solenoid current in order to effect the measurement of solenoid inductance.
[0075] ASIC 198 has the ability to measure the amount of current flowing in or out of the node 208 labeled “Pin” in FIG. 13 . The pin driver circuit 198 in this case uses its A/D converter 216 to measure current flowing into or out of the pin node 208 , thereby enabling the detection of excessive current, or detecting whether a device connected to the Pin node 208 is functioning or wired correctly.
[0076] ASIC 198 also has the ability to monitor the current flow into and out of the pin node 208 to unilaterally disconnect the circuit 198 , thereby protecting the ASIC 198 from damage from short circuits or other potentially damaging conditions. The ASIC 198 employs a so-called “abuse detect circuit” 218 to monitor rapid changes in current that could potentially damage the ASIC 198 . Low current switches 220 , 221 and 222 and high current switch 222 b respond to the abuse detect circuit 218 to disconnect the pin 208 .
[0077] The ASIC 198 abuse detect circuit 218 has the ability to establish a current limit for the pin 208 , the current limit being programmatically set by the microprocessor 80 . This is indicated by selections 224 .
[0078] The ASIC 198 can measure the voltage at the pin node 208 in order to allow the microprocessor 80 to determine the state of a digital input connected to the pin node. The threshold of a digital input can thereby be programmed rather than being fixed in hardware. The threshold of the digital input is set by the microprocessor 80 using the digital-to-analog converter 226 . The output of the digital-to-analog converter 226 is applied to one side of a latching comparator 225 . The other input to the latching comparator 225 is routed from the pin 208 and represents the digital input. Therefore, when the voltage of the digital input on the pin 208 crosses the threshold set by the digital-to-analog converter, the microprocessor 80 is able to determine the change in the input and thus deduce that the digital input has changed state.
[0079] The ASIC 198 can measure a current signal presented at the pin node, the current signal being produced by various industrial control devices. The ASIC 198 can measure signals varying over the standard 4-20 mA and 0-20 mA ranges. This current measurement means is accomplished by the microprocessor 80 as it causes the selectable gain voltage buffer 231 to produce a convenient voltage such as zero volts at its output terminal. At the same time, the microprocessor 80 causes the selectable source resistor 228 to present a resistance to the path of current from the industrial control device and its current output. This current enters the ASIC 198 via the pin 208 . The imposed voltage on one side of a known resistance will cause the unknown current from the external device to produce a voltage on the pin 208 which is then measured via the analog-to-digital converter 216 through the low current switch 222 . The microprocessor 80 uses Ohm's Law to solve for the unknown current being generated by the industrial control device.
[0080] The ASIC 198 includes functions as described above in reference to the interface apparatus 84 . For example, an ASIC 198 can include an interconnection apparatus 83 including a digital-to-analog converter 226 , wherein the microprocessor 80 is programmable to direct the reception of a digital signal from the microprocessor 80 and cause the signal to be converted by the digital-to-analog converter 226 to an analog signal, and to place a copy of the analog signal on the pin 208 . See FIGS. 6 and 13 .
[0081] The ASIC 198 can also include an interconnection apparatus 83 including an analog-to-digital converter 216 , and wherein the microprocessor 80 is programmable to detect an analog signal on any selected contact 16 and cause the analog-to-digital converter 216 to convert the signal to a digital signal and output a copy of the digital signal to the microprocessor 80 .
[0082] The ASIC 198 can also include a supply selector 227 , and a high current switch 222 b positioned between the selector 227 and the pin 208 . The microprocessor 80 is programmable to operate a supply selector 227 to cause a power supply voltage to be connected to a first contact 16 , and to cause a power supply return to be connected to a second contact 16 .
[0083] Referring to FIG. 13 , there is a 2×8 cross-point switch 210 , that serves to connect a sensor to two adjacent pins 208 which are in turn connected to two adjacent device communication connectors 16 . The cross-point switch 210 allows a sensor such as a thermocouple to be connected to a precision differential amplifier 212 . The precision differential amplifier 212 may be connected via the low current switch 222 and the 2×8 cross-point switch 210 to the 4-way cross-point I/O 214 and then to another 4-way cross-point I/O 214 on an adjacent integrated circuit 19 (the integrated circuit for an adjacent contact 16 ).
[0084] Other enhancements of the present invention include the ability of the module 15 to perform independent control of devices connected to the module 15 . If, for example, a solenoid is connected to the module 15 , then the microprocessor 80 can perform the required periodic or continuous measurement of inductance by causing the solenoid voltage to slightly vary and then measure the resulting current using the current measurement apparatuses in the programmable current limiters 224 . In addition, said microprocessor 80 can perform the required steps to shut down the solenoid by throttling or recirculating the current. The module 15 can thereby perform all the functions required to actuate a solenoid and verify its state, whether sealed or open.
[0085] Referring to FIGS. 6 & 7 , the microprocessor 80 is generally configured/programmed by a controller 85 to receive instruction from the controller as required to sense a particular state of a selected device such as solenoid inductance and/or actuate a selected device, such as solenoid 10 , and provide the corresponding data to the system controller. The microprocessor 80 may also be programmed/directed by the controller to cause a particular signal to be applied to any selected one or more contacts 16 . In addition, the microprocessor 80 is programmed to respond to direction to send a selected signal type from one or more of devices to the system controller. In other words, the microprocessor controls the configuration of the interface apparatus 84 and generally the microprocessor is controlled by the system controller. Alternatively, the interface apparatus can be configured in response to a message stored in the memory of the microprocessor 80 of the module 15 .
[0086] In some embodiments, the microprocessor 80 has an embedded web server. A personal computer may be connected to the module 15 using an Ethernet cable or a wireless communication device and then to the Internet. Here the personal computer may also be a system controller. The embedded web server provides configuration pages for each device connected to the module 15 . The user then uses a mouse, or other keyboard inputs, to configure the device function and assign input/output pins. The user may simply drag and drop icons on the configuration page to determine a specific interconnection apparatus for each of the contacts. In other embodiments, the microprocessor 80 uses a network connection to access a server on the Internet and receive from said server instructions to determine a specific interconnection apparatus for each of the contacts.
[0087] As an example of the operation of the module 15 , the microprocessor 80 may be programmed to recognize particular input data, included for example in an Ethernet packet on a network cable connected to said microprocessor containing instructions to actuate a particular solenoid connected to said module 15 .
[0088] The circuit switching apparatus (R 1 -R 12 ) are shown diagrammatically as electromechanical relays. In one embodiment, this switching apparatus is realized in a semiconductor circuit. (See FIG. 13 and related description.) A semiconductor circuit can be realized far less expensively and can act faster than an electromechanical relay circuit. An electromechanical relay is used in order to show the essence of the invention.
[0089] While certain representative embodiments and details have been shown for purposes of illustrating the invention, it will be apparent to those skilled in the art that various changes in the methods and apparatus disclosed herein may be made without departing from the scope of the invention which is defined in the appended claims. | A configurable, connectorized method and apparatus for driving a solenoid coil reduces energy consumption and heating of the solenoid coil, allows detection of the solenoid state, and simplifies connections to the solenoid. | 58,362 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to bolted joints, for use in low thermal expansion materials, and more particularly to a joint assembly wherein a metallic fastener joins material having a low coefficient of thermal expansion to a material having a high coefficient of thermal expansion.
2. Description of the Related Art
With the increasing use of ceramic and other low thermal expansion materials, a problem is encountered when such materials are joined to high thermal expansion materials. Such materials also are typically used in high strength conventional fasteners, such as metallic bolts. Metal fasteners are thermally incompatible with ceramic and other low thermal expansion materials in that the metal expands more than the ceramic material does with an increase in temperature. The coefficient of thermal expansion for metals ranges from 3×10 -6 to 13×10 -6 in./in./°F., with the coefficient of thermal expansion for steel being about 10×10 -6 in./in./°F. On the other hand, ceramic materials have a coefficient of thermal expansion of 1×10 -6 to 2×10 -6 in./in./°F. If a metallic bolt shank is fitted closely within a bore in a ceramic material, cracking of the ceramic material is likely to occur if the joint is exposed to temperature changes.
Various bushings are conventionally used for providing a close fit between a shank and a bore through which the shank passes. Two such bushings are disclosed in U.S. Pat. Nos. 4,156,299 and 3,643,290. However, these devices do not address the problem of differential thermal expansions. Other attempts have been made for joining ceramic and metal parts in a manner that compensates for differential thermal expansions. However such joints have proved complex and costly and they do not eliminate thermally induced stress in the materials being joined.
The problem of fitting a high thermal expansion fastener in the bore of a low thermal expansion material and the problem of compensating for differential expansions between the high and low thermal expansion materials being joined so that thermal stress does not result upon temperature change has not been addressed. The present invention provides a cost efficient solution to this problem.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide a thermal stress-free joint assembly for joining a high thermal expansion material to a low thermal expansion material by means of a high thermal expansion shank within a bore in the low thermal expansion material.
It is another object of the present invention to provide a joint assembly in which a high thermal expansion shank fits closely within a bore in a low thermal expansion material and remains closely fit with temperature changes.
It is additionally an object of the invention to provide a joint assembly that does not experience thermally induced stress with temperature change and that can be produced at a cost that is comparable to the cost of conventional bolted joint assemblies.
Additional objects and advantages of the present invention will be set forth in part in the description that follows and in part will be obvious from the description or may be learned by practice of the invention. The objects and advantages of the invention may be realized and obtained by the apparatus particularly pointed out in the appended claims.
To achieve the objects and in accordance with the purpose of the invention, as embodied and as broadly described herein, a thermal stress-free joint assembly for joining a high thermal expansion material and a low thermal expansion material is provided, comprising: a first member having a bore therethrough, the first member comprised of a first material having a first coefficient of thermal expansion, the bore having a selected cross section; a second member; a fastener comprised of a second material having a second coefficient of thermal expansion, the second coefficient of thermal expansion being greater than the first coefficient of thermal expansion, the fastener including a shank having a selected cross section passing through the bore, the fastener engaging said second member for joining said first and second members; an annular bushing disposed in the bore and having a selected external diameter and a circumferential surface closely engaging the periphery of the bore, an internal circumferential surface closely engaging the shank and at least one frangible portion extending between the external and internal circumferential surfaces, the bushing being comprised of a material having a third coefficient of thermal expansion that is less than the first and second coefficients of thermal expansion, the shank and bore dimensions being selected in accordance with the following equation:
D.sub.1 /D.sub.2 =(α.sub.3 -α.sub.1)/(α.sub.3 -α.sub.2)
where
D 1 =shank cross sectional dimension
D 2 =bore dimension
α 1 =first member coefficient of thermal expansion
α 2 =shank coefficient of thermal expansion.
α 3 =bushing coefficient of thermal expansion
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate the presently preferred embodiment of the invention and, together with the description, serve to explain the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view of a joint assembly according to the preferred embodiment of the invention.
FIG. 2 is a cross-sectional view of the joint assembly shown in FIG. 1 taken along the line A--A.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference will now be made in detail to a presently preferred embodiment of the invention, an example of which is illustrated in the accompanying drawings. Throughout the drawings, like reference characters are used to designate like elements.
According to the present invention, there is provided a joint assembly 10 which includes a first member 12 having a bore therethrough and a second member 26 having an aperture 38. The first member is comprised of a first material having a first coefficient of thermal expansion α 1 , and the bore has a selected cross sectional dimension. As embodied herein, a first member 12 is comprised of a material having a low coefficient of thermal expansion, as for example, a ceramic material with a coefficient of thermal expansion in the range of about 1×10 -6 to about 2×10 -6 in./in./°F. Second member 26 may also be comprised of a metallic material. Member 12 has a bore 14 formed therethrough. Preferably, bore 14 is a circular cylindrical bore having a diameter shown by dimension line 30 in FIG. 2.
According to the present invention, a fastener 15 is provided which is comprised of a second material having a second coefficient of thermal expansion α 2 , the second coefficient of thermal expansion being greater than the first coefficient of thermal expansion α 1 . The fastener has a shank of a selected cross section passing through the bore in the first member and the aperture in the second member. As embodied herein, fastener 15 which may be a bolt includes a head 18 that is integral with shank 16, the latter having a threaded end 17 on which a threaded nut 20 is threadedly engaged. The material of which fastener 15 is made has a coefficient of thermal expansion greater than the coefficient of thermal expansion of member 12. Fastener 15, including shank 16, is preferably made of metal having a coefficient of thermal expansion in the range of about 4×10 -6 to 13×10 -6 in./in./°F. Fastener 15 may be, for example, a conventional metal bolt having a smooth shank 16 and a threaded end 17 on to which a threaded nut 20 is threadedly engaged. Shank 16 has a diameter, as shown by dimension line 32, that is smaller than the diameter of bore 14 as shown by dimension line 30. Shank 16 is disposed within bore 14.
According to the invention, there is further provided an annular bushing 21 disposed in the bore 14. Bushing 21 has an external circumferential surface 34 closely engaged by bore 14, an internal circumferential surface 36 closely surrounding shank 16 and a frangible portion 28 extending between said external and internal circumferential surfaces 34 and 36, respectively. The bushing is comprised of a material having a third coefficient of thermal expansion α 3 that is less than the first and second coefficients of thermal expansion. As embodied herein, an annular bushing 21 is provided between shank 16 and member 12. Bushing 21 has an external diameter substantially equal to the diameter of bore 14 shown by dimension line 30 and an internal diameter substantially equal to the diameter of shank 16 shown by dimension line 32.
According to the preferred embodiment of the invention, bushing 21 is made of a material having a coefficient of thermal expansion substantially equal to zero. Bushing 21 may be comprised of a carbon matrix with carbon fibers formulated in a manner to achieve a coefficient of thermal expansion equal to zero.
According to another embodiment of the invention, bushing 21 is comprised of a material having a coefficient of thermal expansion less than zero. Such a bushing may be comprised of a carbon matrix with carbon fibers formulated to result in a negative thermal expansion material. That is, bushing 21 may be formulated to contract as the temperature of the bushing increases.
The frangible portion 28 of bushing 21 is provided to permit bushing 21 to separate when the diameter of shank 16 increases upon thermal expansion. Frangible portion 28 may be formed as a score line 28a that breaks upon the first expansion of shank 16, or may be formed as a gap 28b which is cut completely through bushing 21. More than one frangible portion 28 may be used, and multiple frangible portions may be arranged equally spaced around the circumference of bushing 21.
According to the invention the cross-sectional dimensions of the shank and bore have the following relationship:
D.sub.1 /D.sub.2 =(α.sub.3 -α.sub.1)/(α.sub.3 -α.sub.2) (1)
where
D 1 =shank cross sectional dimension
D 2 =bore dimension
α 1 =first member coefficient of thermal expansion
α 2 =shank coefficient of thermal expansion.
α 3 =bushing coefficient of thermal expansion
According to the preferred embodiment, the shank and bore are circularly cylindrical and the shank and bore dimensions D 1 and D 2 are the diameters of the shank and bore, respectively. The ratio of the diameter of shank 16 as shown by dimension line 32 to the diameter of bore 14 as shown by dimension line 30 equals the ratio of the difference between the coefficient of thermal expansion of the bushing and the coefficient of thermal expansion of the first member to the difference between the coefficient of thermal expansion of the bushing and the coefficient of thermal expansion of the shank. It can be seen in FIG. 2 that the diameter of bore 14 in member 12 as shown by dimension line 30 is substantially equal to the outer diameter of bushing 21.
According to another preferred embodiment of the invention, the bushing coefficient of thermal expansion α 3 is approximately equal to zero. In this case the relationship between dimensions D 1 and D 2 is as follows:
D.sub.1 /D.sub.2 =α.sub.1 /α.sub.2. (2)
By selecting the dimensions of the fastener, bushing and bore according to either of these equations, (1) or (2), shank 16 will fit closely within bore 14 of member 12 both before and after thermal expansion or contraction of shank 16. In addition, the joint assembly 10 will not experience thermal stress because bushing 21 will separate or converge at frangible portion 28 so that the fit between shank 16 and member 12 remains close without an increase in stress on either member 12 or shank 16.
Washers 22 and 24 may be made from a material having a coefficient of thermal expansion greater than that of fastener 15 so that as shank 16 elongates with increased temperature, washers 22 and 24 increase in thickness to maintain bolt preload by bearing against head 18 and nut 20.
It will be apparent to those skilled in the art that modifications and variations can be made in the joint assembly of this invention. The invention in its broader aspects is, therefore, not limited to the specific details, representative methods and apparatus, and illustrative examples shown and described herein and above. Thus, it is intended that all matter contained in the foregoing description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense. | A thermal stress-free joint assembly for joining a low thermal expansion member and a high thermal expansion member uses a fastener and a bushing fitted within a bore in the low thermal expansion member, wherein the fastener and bushing materials are selected to have predetermined coefficients of thermal expansion. The fastener includes a shank which passes through the bore in the low thermal expansion member. The bushing, bore and shank are dimensioned according to a mathematical relationship to maintain a predetermined clearance or preload as the joint undergoes changes in temperature, without damage to either joined member from thermally induced stress. | 12,936 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a quadrature modulation circuit. In particular, the present invention relates to a quadrature modulation circuit which includes a base band wave reshaping circuit used for digital modulation such as four phase shift keying modulation (QPSK) in which the frequency band is limited by the digital transmission system.
2. Description of the Prior Art
FIG. 8 shows a block diagram of a conventional quadrature modulation circuit used for QPSK. In FIG. 8, an in -phase channel signal 1 i (I-ch) and a quadrature-phase channel signal 1 q (Q-ch) are non-return-to-zero (NRZ) input signals. Low pass filters (ROM LPF) 2 i and 2 q are read only memories (ROM) respectively which operate as band limitation filters for I-ch and Q-ch. Digital to analog converters (D/A converter) 3 i and 3 q convert the digital signals which are received from the ROM LPF 2 i and ROM LPF 2 q , to analog signals. Analog filters 4 i and 4 q suppress the step aliases received from the D/A converters 3 i and 3 q . A quadrature modulation circuit 5 which includes a phase shifter 51, multipliers 52, 53 and an adder 54 modulate a carrier orthogonally with the output signals of the analog filters 4 i and 4 q . An oscillator 6 supplies the modulation carrier signal to the quadrature modulation circuit 5.
FIG. 9 shows a block diagram of the low pass filters (ROM LPF) 2 i and 2 q in FIG. 8. In FIG. 9, an input signal 1 corresponds to the in-phase channel signal 1 i (I-ch) and the quadrature channel signal 1 q (Q-ch). An n-step shift register 21 shifts the input signal 1 in sequence. An oscillator 22 generates a clock signal corresponding to the sample frequency of the ROM LPF 2 i and 2 q . A ROM 24 stores the resulting data of the wave form from the filter.
FIG. 10 shows another block diagram of the low pass filters (ROM LPF) 2 i and 2 q in FIG. 8. A pair of n/2-step shift registers 211 and 212 shift the first half cycle of the input signal and the second half cycle of the input signal respectively. ROMs 241 and 242 store the different wave forms. An adder 25 adds the values received from the ROMs 241 and 242.
The operation of the above conventional art is explained hereinafter. In the digital modulation, such as QPSK, since the frequency component spreads over a wide range, the frequency of the modulated output signal is limited by band limitation filter. A QPSK signal S(t) limited in the base band frequency is expressed in the following equation (1). ##EQU1## where ω c is a carrier frequency, I k and Q k are the digital signals of I-ch and Q-ch and have the value of +1 or -1 and h (t) is the impulse response of the band limitation filter. A nyquist filter having the characteristics of a raised-cosine roll-off is used for the band limitation filter.
The operation of FIG. 8 is explained by referring the equation (1). An in-phase channel signal 1 i (I-ch) and a quadrature channel signal 1 q (Q-ch) are inputted to the low pass filters (ROM LPF) 2 i and 2 q respectively by the form of NRZ signal I k and Q k . Input signals I k and Q k are convoluted to form impulse responses in the low pass filters (ROM LPF) 2 i and 2 q respectively. Smoothed wave forms I (t) and Q (t) are outputted as sampled and quantized numerical data from the low pass filters (ROM LPF) 2 i and 2 q respectively. These output data are inputted to the D/A converters 3 i and 3 q respectively and converted into analog signals. The analog filters 4 i and 4 q smooth the step data converted to the analog signals, suppress the aliases generated at the sampling process, and the output signals I (t) and Q (t) are inputted to the quadrature modulator 5. In the quadrature modulator 5, the carrier signal generated in the generator 6 is distributed into two quadrature carriers -sin ω c and cos ω c which is shifted 90 degrees using a shifter 51. These two carrier signals are applied to multipliers 52 and 53 and are multiplied by the output signals I (t) and Q (t) received from the analog filter 4 i and 4 q respectively. The two outputs from the multipliers 52 and 53 are added in an adder 54 and are outputted as a modulation wave form S (t).
The operations of the ROMs LPF 2 i and 2 q are explained by using FIG. 9 and FIG. 11. The operation of the LPF can be considered as the convolution of the input signal and the impulse response of the LPF. Therefore, they are expressed as the second and the third equations of equation (1).
FIG. 11 shows the convolution result of the equation (1). In FIG. 11, numeral 7 shows input impulse row (I k or Q k ). The upward arrow shows "1" and downward arrow shows "0". 8 is an impulse response wave form [I k ·h(t-kT) or Q k ·h(t-kT)] of the LPF for each input impulse 7. These impulse response wave forms [I k ·h(t-kT) or Q k ·h(t-kT)] are shown in dotted lines. 9 is a filter output wave from [I (t) or Q (t)] in which all impulse response wave forms are added. The filter output wave form [I (t) or Q (t)] is shown in solid line.
The range k of Σ is k=-∞ to ∞. As easily known from each impulse response wave form 8 in FIG. 11, the value of the impulse response becomes negligibly small where |k| is very large. Therefore, the impulse response can be restricted within the finite range. In this example, 5 symbols before and 5 symbols after a certain symbol (total symbols are 10) are used for calculating the convolution of the impulse response. In this case, the impulse response wave form between the "5" symbol and "6" symbol shown in the solid line is calculated using 10 symbols shown in FIG. 11. When the convolution is calculated from the finite impulse response, the filter output wave form I (t) or Q (t) is obtained as the summation of all impulse response wave forms corresponding to each 10 symbols. That is, the impulse response wave form between the "5" symbol and "6" is calculated from only 10 symbols of "1" to "10" symbols.
FIG. 9 shows a ROM LPF which includes the ROM 24 for storing the wave form described above. In FIG. 9, digital signals I k or Q k (input signal 1) are inputted to the n-step shift register 21. The shift register 21 shifts the input data (symbol) in sequence and stores the most recent n symbols and outputs these n symbols to the address of the ROM 24. In this embodiment, as the 10 symbols are used, n is equal to 10.
All combination wave forms of n symbols are calculated beforehand and stored in the ROM 24. In this case, the wave form can not be processed continuously on the time axis. Therefore, the wave forms between two symbols are sampled on the time point of 2 m and the quantized data is stored in the ROM 24. The m bits output from the 2 m binary counter 23 which operates at the sampling clock received from the oscillator 22 is inputted to the ROM 24 as well as the n symbols received from the shift register 21. The ROM LPF in FIG. 9 operates as the LPF by selecting the output wave form stored in the ROM 24 at a time according to the address data constructed of n symbol data received from the shift register 21 and by reading in sequence the b 2 m sampling number between the two symbols which is selected according to the output value from the counter 23.
The capacity of the ROM 24 is decided by the referred symbol data n and the sampling number 2 m between the two symbols. For example, in the case of QPSK, as I k and Q k are expressed by one bit respectively, if n=10 and m=3, then the necessary capacity for the ROM 24 is 2.sup.(n+m) =2 13 =8K words respectively for each I-ch and Q-ch ROM. Further, if n becomes larger in order to make the truncation error of the impulse response smaller, the capacity of the ROM will be increasing exponentially.
FIG. 10 is a block diagram of ROMs LPF 2 i and 2 q configuration which is able to decrease the required capacity of the ROM 24 of FIG. 9. In FIG. 10, the operation of the low pass filter is modified, and expressed by equation (2) which is introduced from the second and third equations of equation (1) as follows. ##EQU2##
In equation (2), the range of the impulse response exists between finite n symbols.
The operation of the FIG. 10 is explained using FIG. 12 and equation (2). The filter output wave form is considered as the summation of the filter output wave forms shown in FIGS. 12(a) and (b). That is, the wave form of the FIG. 12(a) indicates the first term of the right side of equation (2) and FIG. 12(b) indicates the second term of the right side of the equation (2). The reference numbers 71˜91 and 72˜92 in FIG. 12 correspond to the number 7˜9 in FIG. 11.
The wave forms shown in FIG. 12(a) and (b) are stored in a ROM 241 and 242 of FIG. 10 respectively in the same way as stored in the ROM 24 in FIG. 9. Each n/2 data from the shift registers 211 and 212 and m bit data from the counter 23 are inputted to the ROMs 241 and 242 respectively, and the corresponding data are read from the ROMs 241 and 242 respectively. The two output data from the ROM 241 are added in an adder 25. That is, the ROM 241 operates to calculates the first term of the right side of equation (2), the ROM 241 operates to calculates the second term of the right side of equation (2), and the adder 25 calculates the addition of the right side of equation (2).
The n data input is divided into two portions, and the first half n/2 data (k=-n/2˜-1) is stored in the n/2 step shift register 211 and the second half n/2 data (k=0˜n/2 -1) is stored in the n/2 step shift register 212. The address data from the shift register 211 is outputted to the ROM 241, and the address data from the shift register 212 is outputted to the ROM 242. The m bits output from the counter 23 is inputted to the both ROM 241 and 242. The operation of the m bits output is the same as explained in the FIG. 9.
The capacity of the ROMs 241 and 242 in FIG. 10 is calculated as follows. For example, if n=10 and m=3, then the capacity of the both ROMs is 2.sup.(n/2+m) ×2=2 8 ×2=512 words. In the case of 16 QAM, 8 PSK and π/4 shifted DQPSK, the capacity of the ROM is 2.sup.(2×n/2+m) ×2=2 13 ×2=16K words.
As discussed above, the capacity of the ROM of FIG. 10 becomes smaller than that of FIG. 9. But, the capacity of the ROMs 241 and 242 still occupies a considerable amount of memory in the quadrature modulation circuit of FIG. 8. It is also necessary to provide two sets of the same ROM in the quadrature modulation circuit for each I-ch and Q-ch.
There is prior art, for example, laid-open Japanese patent publication No. 63-77246/1988, which describes such quadrature modulation.
As the conventional quadrature modulation is constructed as discussed above, it is necessary to provide a large capacity ROM LPF 2 i and ROM LPF 2 q for each I-ch and Q-ch respectively.
It is a primary object of the present invention to provide a quadrature modulation circuit which requires small capacity ROMs for operating as filters.
It is a further object of the present invention to reduce the hardware size compared with the prior art quadrature modulation circuit having ROMs for operating as filters.
It is a further object of the present invention to reduce the ROM size by using the amplitude symmetry of the wave form.
It is a still further object of the present invention to reduce the ROM size by using the symmetry of the wave form on the time axis.
SUMMARY OF THE INVENTION
A quadrature modulation circuit includes at least a low pass filter for limiting the frequency band of the in-phase channel and the quadrature channel, along with at least a D/A converter for converting the digital signals received from the low pass filters to analog signals. The quadrature modulation circuit also includes at least a filter for suppressing the aliases outputted from the D/A converters and a quadrature modulator for modulating the outputs from the filters. In the quadrature modulation circuit, the low pass filters operate by a time division sequence for the inphase channel and the quadrature channel. The low pass filters also use one symbol as a sign data and invert the sign of the remaining symbol data and that of the data read out from the ROM. The low pass filters divide the reference data into the first half portion and the second half portion, and read out of the contents from the ROM for the forward direction of the time axis at the first half portion, and for the backward direction of the time axis at the second half portion.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows a block diagram of a first embodiment of a quadrature modulation circuit of the present invention.
FIG. 2 shows a block diagram of a construction of a ROM LPF of the embodiment of FIG. 1.
FIG. 3 shows the symmetrical signal wave form on the time axis.
FIG. 4 shows the symmetrical signal wave form in terms of amplitude.
FIG. 5 shows a block diagram of a second embodiment of a quadrature modulation circuit of the present invention.
FIG. 6 shows a block diagram of a third embodiment of a quadrature modulation circuit of the present invention.
FIG. 7 shows a block diagram of a construction of the ROM LPF of FIG. 6.
FIG. 7b shows a block diagram of another construction of the ROM LPF of FIG. 6.
FIG. 8 shows a block diagram of a conventional quadrature modulation circuit.
FIG. 9 shows a block diagram of a construction of a ROM LPF of FIG. 8.
FIG. 10 shows a block diagram of another construction of a ROM LPF of FIG. 8.
FIG. 11 shows the wave form of the ROM of the FIG. 9.
FIG. 12 shows the wave form of the ROM of the FIG. 10.
FIG. 13 shows a time chart which gives wave forms for some points in FIG. 2.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a first embodiment of the present invention. In FIG. 1, signals 1 i and 1 q are inputted signals of I-ch and Q-ch respectively. A selector 10 switches the input signals 1 i and 1 q to a ROM 20 by a time division process. A ROM 20 is a ROM LPF which stores a half of the wave form data using the symmetry characteristic of the wave form data. The adoption of the ROM LPF decreases the capacity of the memory. A demultiplexer 11 demultiplexes the output signal from the ROM 20 by a time division process. D/A converters 3 i and 3 q convert the input digital signals into analog signals for the I-channel and the Q-channel respectively. Analog filters 4 i and 4 q smooth the analog signals, suppress the aliases generated at the sampling process, and output I (t) and Q (t) signals to the quadrature modulator 5 respectively. A quadrature modulator 5 modulates the input I (t) and Q (t) signals with the distributed two signals in the same manner as explained in FIG. 8. An oscillator 6 supplies the modulation carrier signal to the quadrature modulator 5.
FIG. 2 shows a block diagram of the selector 10 and the ROM LPF 20 of FIG. 1. In FIG. 2, n/2 step shift registers 211 i , 211 q , 212 i and 212 q shift the input 1 i and 1 q signals in sequence respectively. A selector 100 selects one of the outputs from the shift registers 211 i , 211 q , 212 i and 212 q . Exclusive ORs 202 and 204 operate so that the amplitude symmetry of the wave form is used for calculating the output signal. Exclusive OR 203 operates so that the symmetry of time axis of the wave form is used for calculating the output signal. A ROM 201 is addressed by the outputs of the exclusive ORs 202 and 203 and outputs the data to an exclusive OR 204. An adder 251 adds the output from the exclusive OR 204. A latch circuit 206 latches the output from the adder 251 and uses it for the succeeding addition. An oscillator 221 generates a clock signal which is supplied to a counter 231 for counting the clock. A timing generator 207 generates the latch clock signal (CK) and clear signal (CLR) for the latch circuit 206 from the clock signal received from the counter 231.
The operation of the first embodiment is explained hereinafter using FIG. 1 and FIG. 2. In FIG. 1, signals 1 i and 1 q are inputted to the selector 10. The selector 10 switches the input signals 1 i and 1 q to the ROM LPF 20 by a time division process. The ROM LPF 20 stores the filtered wave form data. Needed memory of which is reduced by utilizing the symmetric characteristics of the wave form. The same ROM LPF 20 is used both for the in-phase channel and the quadrature channel by a time division process. The demultiplexer 11 demultiplexes the output signal from the ROM LPF 20 and sends it to the D/A converters 3 i and 3 q by a time division process. Each D/A converter 3 i and 3 q converts the input digital signal into an analog signal. Each analog filter 4 i and 4 q smoothes the analog signal, suppresses the aliases generated at the sampling process, and outputs I (t) and Q (t) signals to the quadrature modulator 5 respectively. The quadrature modulator 5 modulate a carrier orthogonally with the output signals of the analog filters 4 i and 4 q .
More detailed explanation is made in connection with the ROM LPF 20 of FIG. 1 using FIG. 2, FIG. 3, FIG. 4 and FIG. 13.
Firstly, it is explained how the required capacity of the ROM is reduced by half compared with the prior art using the symmetry characteristic of the signal wave form on the time axis.
FIG. 3 shows the symmetrical characteristic of the signal wave form on the time axis. Numerals 73 and 74 are inputted impulse rows respectively, and numerals 83 and 84 are impulse responses for each input impulse. Numerals 93 and 94 are outputted signal wave forms from the filter which are obtained as the summation of all impulse responses 83 and 84 respectively. As discussed above, in the conventional art, it is necessary to provide the ROMs 241 and 242 for storing the first half n/2 symbols and the second half n/2 symbols respectively. But, the data stored in the ROM 241 is the same as the data stored in the ROM 242 in which the data address is reversely arranged.
FIG. 3(a) shows the wave form which is read out from the ROM 241 of FIG. 10 at the case of n=10 and the first half five bits are "01011". On the other hand, FIG. 3(b) shows the wave form which is read out from the ROM 242 of FIG. 10 for the case of n=10 and where the second half five bits are "11010". Comparing the two wave form, it is apparent that, if the time axis is reversed, FIG. 3(b) becomes the same as FIG. 3(a). That is, the wave form of the FIG. 3(b) can be obtained by changing the data sequence from "11010" to "01011", and by reversing the counter number which indicates the sampling position, namely by reversing the time axis and reading out the wave form from the ROM 241. As discussed above, by changing the address data, the wave forms of FIG. 3(a) and FIG. 3(b) can be read out from the same ROM 201 as shown in FIG. 2.
Secondly, it is explained that the required capacity of the ROM is reduced by half compared with the prior art using the amplitude symmetry of the wave form of FIG. 4.
FIG. 4 shows the wave form which explains the amplitude symmetry. In FIG. 4, numbers 75 and 76 are inputted impulse sequences respectively, and numbers 85 and 86 are impulse responses for each input impulse. Numbers 95 and 96 are the output signal wave forms of the filter which convolutes the impulse responses 85 and 86 respectively. FIG. 4(a) shows the wave form which is read out from the ROM 241 of FIG. 10 for the case of n=10 and where the first half five bits are "01011". On the other hand, FIG. 4(b) shows the wave form which is read out from the ROM 241 of FIG. 10 for the case of n=10 and where the first half five bits are "10100" which is the reversed wave form of the FIG. 4(a). Comparing the two wave forms, it is apparent that, by multiplying by (-1), these wave forms are easily transformed each other. The operation for multiplying the wave form by (-1) is attained by inverting each bit and adding 1 to the inverted bits in the case of the two's compliment of the binary. Further, in the case where the wave form is expressed by the sign bit and the absolute value of the remaining bits, the inversion of the amplitude of the wave form is attained only by inverting the sign bit.
As explained above, the operation for multiplying by (-1) is attained easily by simple hardware. Therefore, the required capacity of the ROM is reduced by half by storing the half wave form in the ROM shown in FIG. 4(a), and by multiplying the output wave form by (-1).
The method for reversing the amplitude symmetry wave form is explained hereinafter. For example, the data on the time axis "5" in FIG. 4(a) is continuously supervised, and if the data on the time axis "5" is "0", then the data of the time axis "1"˜"4" are supplied to the ROM 201 as the address data, and if the data on the time axis "5" is "1", then the data of the time axis "1"˜"4" are inverted and supplied to the ROM 201 as the address data. The read out data from the ROM 201 is multiplied by (-1) in the exclusive OR 204.
In FIG. 2, the above two symmetry (time axis and amplitude) process and time division process for I channel and Q channel is used. Therefore, the required capacity of the ROM is reduced by one eighth in comparison with the conventional ROM filter.
The operation of FIG. 2 is explained hereinafter. In FIG. 2, the first half of the input signal 1 i is stored in the register 211 i and the second half of the signal 1 i is stored in the register 212 i in the same way as described in FIG. 10. The first half of the input signal 1 q is stored in the register 211 q and the second half of the signal 1 q is stored in the register 212 q . The first n/2 symbols are obtained from the register 211 i and 211 q , and the second n/2 symbols are obtained from the registers 212 i and 212 q .
A selector 100 selects the input signal from the registers 211 i , 211 q , 212 i and 212 q by the combination of the control signal S 1 and S 0 .
FIG. 13 shows a time chart which gives wave forms of the signals S 1 , S 0 , latch clock signal CK and clear signal CLR in FIG. 2 and the timing relation between them. Latch clock signal CK and the clear signal CLR are generated in the timing generator 207 of FIG. 2. The select signal S 1 switches the I channel and Q channels at a sampling point. The select signal S 0 switches the first half symbols and the second half symbols of the I channel and the Q channel at a sampling point. That is, the output of the register 211 i is selected when S 1 and S 0 are (00), and the output of the register 212 i is selected when S 1 and S 0 are (01). In the same way, the output of the register 211 q is selected when S 1 and S 0 are (10) and the output of the register 212 q is selected when S 1 and S 0 are (11).
When the select signal S 0 is 1, the outputs from the register 212 i and 212 q are reversed in order, and also each bit of the output of the time counter 231 is inverted by the select signal S 0 (=1) which is inputted to the exclusive-OR 203. The above reverse of the register 212 i and the register 212 q is executed by changing the connection between the registers 212 i , 212 q and the selector 100. As discussed above, the symmetry of the wave form on the time axis is attained.
The output data selected by the select signal S 1 and S 0 is separated to a specific bit symbol for indicating the sign of the wave form and the remaining (n/2-1) bit symbols in order to use the symmetry characteristic of the amplitude of the wave form. These remaining (n/2-1) bit symbols are inputted as the address input to the ROM 201. The sign bit is inputted to the exclusive-OR 202 which inverts the address data. Further, the sign bit is inputted to an exclusive-OR 204 and an adder 251. The output data is processed as two's compliment. Multiplication by (-1) is executed at the exclusive-OR 204 and at the adder 251 by applying "1" to the least significant carry bit.
In FIG. 2, the impulse response of the first half of the wave form and the impulse response of the second half of the wave form are processed by time division process. Therefore the output of the I channel and Q channel can not be added at a time as shown in FIG. 10. In this circuit, the addition in the adder 251 is executed as follows.
Firstly, a latch circuit 206 is cleared by the clear pulse CLR received from the timing generator 207 before the first half of the wave form is read out from the ROM 201. After the first half of the wave form is read out from the ROM 201, the latch circuit 206 stores the read out first half of the wave form.
Secondly, the second half of the wave form is read out from the ROM 201. The output from the adder 251 shows the addition result of the first half and the second half of the wave form. As a result, the output wave form processed by the ROM LPF is obtained from the adder 251.
FIG. 5 shows a block diagram of a second embodiment of a quadrature modulation circuit of the present invention. In FIG. 5, a D/A converter 30 is provided which operates by a time division process for I channel and Q channel.
The output analog signal from the D/A converter 30 is sampled alternately by the sample hold circuits 12i and 12q, demultiplexed into the I channel and the Q channel. The sample hold circuits 13i and 13q operate by the same timing, and align the phase of the I channel and the Q channel.
The other operations are the same as those described in FIG. 1. Therefore the detailed description is omitted. The above embodiments are described using QPSK, but they may also be applied using other forms of modulation, such as 8 PSK, π/4 shifted DQPSK and QAM. The advantages of the other applications are the same as with the present embodiments.
FIG. 6 shows a block diagram of a third embodiment of a quadrature modulation circuit of the present invention which is applied to the Gaussian filtered minimum phase shift keying modulation (GMSK). In FIG. 6, the same reference numbers as used in FIG. 1 are used to refer to the same portions or the corresponding portions. Accordingly the detailed explanation of such portions is omitted in connection with the same reference numbers.
In FIG. 6, a signal 101 is inputted to a ROM LPF 20. An adder 14 adds the signal from the ROM LPF 20. A latch 15 stores the output signal from the adder 15 which is then added to the succeeding output from the ROM LPF 20. A COS ROM 16 and a SIN ROM 17 convert the output phase from the adder 14 to I channel signal and Q channel signals respectively.
In the case of GMSK, input signal 101 is smoothed in the ROM LPF 20. The output signal from the ROM LPF 20 is integrated in sequence by the adder 14 and the latch 15, and the signal in the frequency domain is converted into the signal in the phase domain. After that, the outputs from the COS ROM 16 and the SIN ROM 17 are converted to analog signals in the D/A converter 3 i , 3 q and supplied to the quadrature modulator 5 through LPF 4 i and 4 q .
FIG. 7 shows a detailed block diagram of the construction of the ROM LPF 20 of FIG. 6 using amplitude symmetry characteristic. In FIG. 7, numeral 2010 is a ROM, numeral 2040 is a calculator which multiplies the output from the ROM 2010 by (-1) selectively. In FIG. 7, the same reference number to the FIG. 2 and FIG. 9 is the same portion or the corresponding portion. Accordingly the detailed explanation of the portion is abbreviated in connection with the same number.
The operation of the embodiment of FIG. 7 is explained hereinafter. The input signal 101 is stored in a shift register 21. One bit of the output signal from the shift register 21 is used as a sign bit and applied to the exclusive-OR 202 and the calculator 2040. The sign bit (1 bit) and the remaining (n-1) bits from the shift register 21 are inputted into the exclusive-OR 202. The remaining (n-1) bits are used as address bits. As discussed above, the output signal from the ROM 2010 is multiplied by (-1) in the calculator 2040 when the sign bit is "1". In this manner, the required capacity of the ROM is reduced by half using amplitude symmetry characteristic.
FIG. 7b shows a detailed block diagram of the construction of the ROM LPF 20 of FIG. 6 using the symmetry on the time axis. In FIG. 7b, 1001 is a selector which selects one of the outputs from the shift registers 211,212. 2011 is a ROM. 2211 is a generator which generates the clock signal. 2311 is a counter which counts the clock signal. 2071 is a timing generator which generates a latch clock and a clear signal.
In FIG. 7b, the same reference numbers as used in FIG. 2 are used to refer to the same portions or corresponding portions. Accordingly the detailed explanation of such portions is omitted in connection with the same reference numbers.
The operation of the embodiment of FIG. 7b is explained hereinafter. The input signal 101 is stored in shift registers 211 and 212. The first half n/2 symbols of the input signal 101 is stored in the shift register 211 and the second half n/2 symbols of the input signal 101 is stored in the shift register 212. The select input signal S 0 selects the first half n/2 symbols or the second half n/2 symbols, that is, the output of the register 211 or 212. When the select input signal S 0 is "1", the selector 1001 selects the second half n/2 symbols from the register 212. In order to use symmetry on the time axis, the output from the register 212 is reversed and the counter data from the counter 2311 is also inverted in the exclusive-OR 203 by the S 0 bit as explained in connection with FIG. 2.
The impulse responses of the first half wave form and the second half wave form are read from the ROM 2011 by time division process. The output data from the ROM 2011 is added in the same way using the adder 251 and the latch 206 as described in connection with FIG. 2. As a result, the filter output wave form is obtained from the output of the adder 251.
In this manner, the required capacity of the ROM is reduced by half using symmetry wave form on the time axis.
The above embodiment are described for applying GMSK, but it may be applied to the tamed FM and other digital FM modulation systems. The advantages of the other applications are the same as in this embodiment. | A quadrature modulation circuit includes a low pass filter which operates by a time division process for the in-phase channel and quadrature-phase channel, and reduces address requirements data using amplitude symmetry of the wave form and/or using symmetry wave form on the time axis. The capacity of the ROM is reduced by half or more and the configuration of the quadrature modulation circuit is simplified. | 30,875 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority from Japanese application JP2016-023783 filed on Feb. 10, 2016, the content of which is hereby incorporated by reference into this application.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a display device and a manufacturing method thereof, and particularly to a flexible display.
[0004] 2. Description of the Related Art
[0005] A flat panel display such as an organic electroluminescence (EL) display device has a display panel in which a thin film transistor (TFT), an organic light-emitting diode (OLED) and the like are formed on a substrate. Conventionally, a glass substrate is used for the base member of the display panel. However, recently, the development of a flexible display using a resin film or the like as the base member to enable the flexure of the display panel is under way.
[0006] As a structure of the organic EL display device, an element substrate having a display area where an OLED as a display element is formed, and a counter substrate on which a color filter or the like is formed and which is arranged opposite the display area of the element substrate, are bonded together. To secure reliability, the element substrate and the counter substrate are bonded together with a filler held between these substrates. In this case, a method may be used in which a dam having a convex structure is formed at an outer peripheral part of the counter substrate, then the filler is dripped into the dam, and the element substrate and counter substrate are thus bonded together. This dam plays the role of preventing the filler from protruding to the outside. The dam is formed by applying a fluid material onto the outer perimeter of the panel with a dispenser or the like and then hardening the fluid material.
[0007] Also, a layer (substrate layer) in which a plurality of the flexible element substrates and counter substrates are arranged is formed on a support plate such as a glass substrate, and after the two substrates are bonded together on each support plate, the resulting structure is divided into a plurality of display panels.
SUMMARY OF THE INVENTION
[0008] In order to achieve a narrow frame on a high-definition display panel, a dam needs to be patterned with a smaller width and higher precision. However, with the technique of dripping the dam material from the nozzle of the dispenser, high-precision patterning is difficult.
[0009] Also, the dam material dripped from the dispenser and hardened is relatively flexible and will not easily crack. Therefore, when dividing the integrally formed plurality of display panels into the individual display panels, laser cutting or the like is used, and a relatively simple technique such as scribe and break cannot be used.
[0010] The invention is to provide a display panel which can be processed with higher precision by a simpler technique, when producing display panels by a so-called multiple formation, that is, stacking a substrate disposed a plurality of element substrates and a substrate disposed a plurality of counter substrates and then dividing the stacked substrate into a plurality of display panel, and in which the frame can be narrowed by reducing redundant areas between the substrates, and a manufacturing method thereof.
[0011] A display device according to an aspect of the invention includes: an element substrate including a flexible multilayer structure having a resin film as a base member, and having a display area where a display element is formed; a counter substrate including a flexible multilayer structure having a resin film as a base member, and stacked on the display area of the element substrate; and a filler filling a space between the element substrate and the counter substrate. Each of the element substrate and the counter substrate has a rib which includes a covalently or ionically bonding inorganic material and which is in contact with an outer peripheral lateral surface of the multilayer structure.
[0012] A manufacturing method of a display device according to another aspect of the invention is a manufacturing method of a display device having a flexible element substrate including a display area where a display element is formed, and a flexible counter substrate bonded to the display area of the element substrate with a filler held between the substrates. The manufacturing method includes: forming a first substrate layer in which a plurality of the element substrate is arranged, on one main surface of a first support plate; forming a second substrate layer in which the counter substrate is provided at each position facing the display area of each of the element substrates in the first substrate layer, on one main surface of a second support plate; bonding the first substrate layer on the first support plate to the second substrate layer on the second support plate and thus forming a substrate layer joined body; and dividing the first substrate layer together with the first support plate, dividing the second substrate layer together with the second support plate, and thereby dividing the substrate layer joined body held between the first and second support plates, into a plurality of parts, each part corresponding to the display device. The forming of the first substrate layer includes forming a ridge-like first rib including a covalently or ionically bonding inorganic material along an edge of the element substrate. The forming of the second substrate layer includes forming a counter area part made of a material including a flexible resin film and arranged opposite the display area, and a second rib including a covalently or ionically bonding inorganic material and in the form of a ridge surrounding the counter area part and higher than the counter area part. The bonding includes filling, with a filler, a recess part in the second substrate layer generated at the counter area part due to a height difference from the second rib. The dividing includes scribing the first and second support plates along the first and second ribs, and flexing and breaking the first and second support plates that are scribed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a schematic view showing a schematic configuration of an organic EL display device according to an embodiment of the invention.
[0014] FIG. 2 is a schematic vertical cross-sectional view of a display panel according to the embodiment of the invention.
[0015] FIG. 3 is a schematic process flowchart of the manufacturing method of the organic EL display device according to the embodiment of the invention.
[0016] FIG. 4 is a schematic vertical cross-sectional view of each of a first substrate layer after the completion of a first substrate layer forming process, and a second substrate layer after the completion of a second substrate layer forming process.
[0017] FIG. 5 is a schematic vertical cross-sectional view of the state where the first substrate layer and the second substrate layer are bonded together.
[0018] FIG. 6 is a schematic plan view of the first substrate layer and the second substrate layer.
DETAILED DESCRIPTION OF THE INVENTION
[0019] Hereinafter, a form of embodying the invention (hereinafter referred to as an embodiment) will be described with reference to the drawings.
[0020] The disclosure is only an example, and as a matter of course, any change that can be easily thought of by a person skilled in the art without departing from the spirit of the invention should be included in the scope of the invention. In order to clarify the explanation, the drawings may schematically show each part in terms of its width, thickness, shape and the like, compared with the actual configuration. However, this is simply an example and should not limit the interpretation of the invention. Also, elements similar to those described before with reference to already mentioned drawings may be denoted by the same reference signs, and detailed description of these elements may be omitted when appropriate.
[0021] The display device according to the embodiment of the invention is an organic EL display device. The organic EL display device is an active-matrix display device and is installed in a television, personal computer, mobile terminal, mobile phone and the like.
[0022] FIG. 1 is a schematic view showing a schematic configuration of an organic EL display device 2 according to the embodiment. The organic EL display device 2 has a pixel array part 4 which displays an image, and a drive unit which drives the pixel array part 4 . The organic EL display device 2 is a flat panel display and has a display panel. The display panel includes a display area where the pixel array part 4 is arranged, and a non-display area.
[0023] In the pixel array part 4 , an OLED 6 as a display element and a pixel circuit 8 are arranged in the form of a matrix corresponding pixels. The pixel circuit 8 is made up of a plurality of TFTs 10 , 12 and a capacitor 14 .
[0024] Meanwhile, the drive unit includes a scanning line drive circuit 20 , a video line drive circuit 22 , a drive power-supply circuit 24 , and a control device 26 . The drive unit drives the pixel circuit 8 to control the light emission of the OLED 6 .
[0025] The drive unit can be arranged in the non-display area of the display panel. The drive unit can be formed on the element substrate forming the display panel together with the pixel circuit 8 . Also, the drive unit may be put in an integrated circuit (IC) produced separately from the pixel circuit 8 , and this IC may be installed within the display panel or on a flexible printed circuit (FPC) connected to the display panel.
[0026] The scanning line drive circuit 20 is connected to a scanning signal line 28 provided for each horizontal line of pixels (pixel row). The scanning line drive circuit 20 sequentially selects a scanning signal line 28 in response to a timing signal inputted from the control device 26 , and applies a voltage to switch on the lighting TFT 10 , to the selected scanning signal line 28 .
[0027] The video line drive circuit 22 is connected to a video signal line 30 provided for each vertical line of pixels (pixel column). The video line drive circuit 22 has a video signal inputted from the control device 26 , and outputs a voltage corresponding to the video signal for the selected pixel row to each video signal line 30 , simultaneously with the selection of the scanning signal line 28 by the scanning line drive circuit 20 . This voltage is written in the capacitor 14 via the lighting TFT 10 , in the selected pixel row. The drive TFT 12 supplies a current corresponding to the written voltage to the OLED 6 , and this causes the OLED 6 of the pixel corresponding to the selected scanning signal line 28 to emit light.
[0028] The drive power-supply circuit 24 is connected to a drive power-supply line 32 provided for each pixel column, and supplies a current to the OLED 6 via the drive power-supply line 32 and the drive TFT 12 in the selected pixel row.
[0029] Here, the anode of the OLED 6 is connected to the drive TFT 12 . Meanwhile, the cathode of each OLED 6 is basically connected to the ground potential, and the cathodes of the OLEDs 6 of all the pixels are formed by a common electrode.
[0030] FIG. 2 is a schematic vertical cross-sectional view of a display panel 40 . The display panel 40 includes an element substrate 42 and a counter substrate 44 bonded to each other.
[0031] The element substrate 42 has a display area 46 and a non-display area 48 . In the display area 46 of the element substrate 42 , the pixel array part 4 is provided as already described. In the non-display area 48 , a wiring 50 led out of the pixel array part 4 in the adjacent display area 46 is formed. Also, in the non-display area 48 , a terminal 52 for connecting the drive unit to the wiring 50 or a circuit of the drive unit can be formed, and an IC can be arranged. FIG. 2 shows an example in which an FPC 54 is connected to the terminal 52 provided in the non-display area 48 .
[0032] The pixel array part 4 , the wiring 50 , the terminal 52 and the like are formed on one main surface of a base member 56 made of a flexible resin film. For example, the base member 56 can be formed using polyimide, epoxy, acrylic, polyethylene naphthalate, and a thermoplastic fluorine resin such as tetrafluoroethylene-ethylene copolymer.
[0033] The pixel array part 4 has a multilayer structure including a circuit layer in which electronic circuits such as the pixel circuit 8 , the scanning signal line 28 , the video signal line 30 , and the drive power-supply line 32 are formed, and an OLED layer in which an OLED is formed, or the like. The OLED layer includes a pixel electrode, an organic material multilayer part, a common electrode, and a bank. The pixel electrode, the common electrode, and the organic material multilayer part held between these electrodes form the OLED. Also, basically, the common electrode contacts the organic material multilayer parts of all the pixels in the display area. Meanwhile, the pixel electrode is formed separately for each pixel and is connected to the drive TFT 12 shown in FIG. 1 and formed in the circuit layer. The common electrode and the pixel electrode is formed using a transparent conductive material such as IZO (indium zinc oxide) or ITO (indium tin oxide). The organic material multilayer part has a light emitting layer. The light emitting layer has holes and electrons injected therein in response to the voltage applied to both electrodes, and emits light due to the recombination of these holes and electrons.
[0034] The OLED layer is stacked on the circuit layer, and a cover layer 58 is stacked on the OLED layer. The cover layer 58 is made of a film with a moisture-proof function and protects the OLED from property deterioration due to moisture. For example, a layer made of silicon nitride (SiN) is stacked as the cover layer 58 .
[0035] An end part 60 made of a covalently bonding inorganic material or an ionically bonding inorganic material is in tight contact with the outer peripheral lateral surface of the base member 56 . The end part 60 has a moisture-proof function on the lateral surface of the base member 56 or the like. Also, the back side of the element substrate 42 , that is, the side opposite to the side where the pixel array part 4 is formed, of the base member 56 , is covered by a barrier layer 62 having a moisture-proof function.
[0036] The counter substrate 44 is stacked on the display area 46 of the element substrate 42 . The counter substrate 44 has a counter area part which is arranged opposite the display area 46 , and an end part 64 which surrounds the counter area part and is higher than the counter area part. The counter area part has a multilayer structure using a flexible resin film as a base member 66 , and a color filter and a barrier layer (hereinafter these two are collectively referred to as a color filter layer 68 ) and the like are stacked on one main surface of the base member 66 . The base member 66 can be formed using the materials mentioned above with respect to the base member 56 , for example. The end part 64 is made of a covalently bonding inorganic material or an ionically bonding inorganic material and is in tight contact with the outer peripheral lateral surface of the base member 66 . The end part 64 has a moisture-proof function on the lateral surface of the base member 66 and the like. Also, the back side of the counter substrate 44 , that is, the side opposite to the side where the color filter layer 68 is formed, of the base member 66 , is covered by a barrier layer 70 having a moisture-proof function.
[0037] In the element substrate 42 , the cover layer 58 may cover the base member 56 in an area excluding the wiring 50 , of the non-display area 48 . Also, an underlying layer made up of a silicon nitride film and a silicon oxide film may be provided between the pixel array part 4 and the base member 56 , and this underlying layer may exist in the entirety of the display area 46 and the non-display area 48 . Since the cover layer 58 , the end part 60 , the barrier layer 62 , and the underlying layer, which do not easily pass oxygen or moisture through, are thus provided on the top surface, the bottom surface, and the lateral surface of the base member 56 , moisture or oxygen does not enter the base member 56 . Similarly, in the base member 66 of the counter substrate 44 , since the color filter layer 68 , the end part 64 , and the barrier layer 70 , which do not easily pass moisture or oxygen through, are provided on the top surface, the bottom surface, and the lateral surface, moisture or oxygen does not enter the base member 66 .
[0038] The element substrate 42 and the counter substrate 44 are bonded together in such a way that the surface where the pixel array part 4 and the like are formed, of the element substrate 42 , and the surface where the color filter layer 68 is formed, face each other. Here, the surface where color filter layer 68 is formed, of the counter substrate 44 , is a recess part in the counter area part due to the height difference between the end part 64 and the counter area part. This recess part is filled with a filler 72 when bonding the two substrates 42 , 44 together. The filler 72 fills the space between the element substrate 42 and the counter substrate 44 and hardens and thus bonds the two substrates together.
[0039] In the part where the edge of the element substrate 42 and the edge of the counter substrate 44 coincide with each other, the top surface of the end part 60 and the top surface of the end part 64 face each other. In this part, the two substrate 42 , 44 are in tight contact with each other, preventing the filler 72 from leaking out. Meanwhile, in the part where the edge of the counter substrate 44 and the edge of the element substrate 42 do not coincide with each other, specifically, in the boundary part between the display area 46 and the non-display area 48 of the element substrate 42 , a dam material 74 is stacked on the element substrate 42 in order to prevent the formation of a space between the top surface of the end part 64 and the top surface of the element substrate 42 and the entry of the filler 72 into the space.
[0040] To protect the joined body of the element substrate 42 and the counter substrate 44 , protection films 76 , 78 are bonded onto the outer surfaces of the substrates, that is, onto the barrier layers 62 , 70 .
[0041] Next, the manufacturing method of the organic EL display device 2 will be described. The manufacturing method of the organic EL display device 2 according to the invention is characterized by the manufacturing method of the display panel 40 . In this manufacturing method, the multilayer structures of a plurality of display panels 40 are formed integrally.
[0042] FIG. 3 is a schematic process flowchart of the manufacturing method. This process flow is made up of a series of steps for forming a first substrate layer in which the structures of a plurality of element substrates 42 are arranged on one main surface of a first support plate (first substrate layer forming process: Steps S 10 to S 15 ), a series of steps for forming a second substrate layer in which the structure of each counter substrate 44 is provided at a position facing the display area 46 of each element substrate 42 in the first substrate layer, on one main surface of a second support plate (second substrate layer forming process: Steps S 20 to S 24 ), and a series of steps (Steps S 30 to S 33 ) for assembling the first substrate layer and the second substrate layer into the display panel 40 .
[0043] FIG. 4 is a schematic vertical cross-sectional view of the first substrate layer after the completion of the first substrate layer forming process and the second substrate layer after the completion of the second substrate forming process. In this illustration, the direction of and horizontal positional relation between the two substrate layers are the same as those at the time of bonding these substrate layers. FIG. 5 is a schematic cross-sectional view of the state where the two substrate layers are bonded together.
[0044] FIG. 6 is a schematic plan view of a first substrate layer 200 and a second substrate layer 202 . The position of the cross section shown in FIGS. 4 and 5 is the same as in FIG. 2 , and this position is indicated by a segment A-A in FIG. 6 . In FIG. 6 , one element substrate 42 arranged in the first substrate layer 200 and one counter substrate 44 arranged in the second substrate layer 202 are indicated by hatching. The element substrate 42 has a rectangular planar shape. In FIG. 6 , the area above the dotted line in this rectangle is the display area 46 , and the area below the dotted line is the non-display area 48 . The counter substrate 44 has a rectangular planar shape, too, and has a shape basically coincident with the display area 46 of the element substrate 42 . When the first substrate layer 200 and the second substrate layer 202 are bonded together, three sides of the four sides forming the outline of the counter substrate 44 overlap with the outline of the element substrate 42 , and the remaining one side is situated at the boundary between the display area 46 and the non-display area 48 .
[0045] Since the element substrate 42 is flexible, a support plate 90 which holds the element substrate 42 in a flat state is prepared at the beginning of the first substrate layer forming process (Step S 10 ). As the support plate 90 , a material suitable for the scribe and break technique is used. For example, the support plate 90 is formed using glass. In this embodiment, in order to produce a plurality of display panels 40 in one shot as described above, the support plate 90 in a shape and size that allows a plurality of element substrate 42 to be arranged thereon is prepared. In the example shown in FIG. 6 , three by three element substrates 42 , in the directions of length and width, are arranged on the support plate 90 .
[0046] First, the first substrate layer forming process will be described. A sacrificial layer (not illustrated) used at the time of stripping the element substrate 42 from the support plate 90 , and the barrier layer 62 having a moisture-proof function are stacked in order on the support plate 90 (Step S 11 ). The sacrificial layer is preferably made of a metal or metal oxide. Titanium (Ti), tungsten (W) or oxides thereof may be used. The barrier layer 62 is made up of a silicon nitride film, silicon oxide film, silicon carbonitride film, silicon carbide film, or multilayer structure of these films.
[0047] A ridge-like first rib 92 is formed using a covalently or ionically bonding inorganic material, on the barrier layer 62 along the edge of the element substrate 42 (Step S 12 ). In FIG. 6 , the element substrate 42 is in contact with the edge of the adjacent element substrate 42 , and these element substrates 42 share the rib 92 provided along the side in the direction of length. Meanwhile, in the example of FIG. 6 , since a margin area 94 is provided between the element substrates 42 next to each other in the direction of length, the rib 92 provided along the side in the direction of width of the element substrates 42 is not shared between the element substrates 42 .
[0048] As a method for forming the rib 92 , patterning using a photolithography technique, a printing method, an aerosol deposition method, sheet pasting or the like can be used. Incidentally, the aerosol deposition method is a high-speed coating method in which fine particles of ceramics, metal or the like as a powder material are sprayed, thus enabling solidification and densification at room temperature without needing a binder or pre-heating of the base member. The rib 92 is formed of a covalently or ionically bonding inorganic material as described above, due to its characteristic of being susceptible to cracking, compared with an organic material like resin or a metal, and therefore suitable for the scribe and break technique. For example, the rib 92 is formed of SiN, silicon oxide (SiO), ITO or the like. Moreover, the same material as the sacrificial layer may be used for the rib 92 , and a metal oxide or metal nitride may be used. A material that can easily crack and does not easily pass water and oxygen through is preferable for the rib 92 . The thickness (height) of the rib 92 is set to be basically the same as or slightly greater than the thickness of the multilayer structure that is subsequently formed in the area surrounded by the rib 92 .
[0049] In the area surrounded by the rib 92 , the base member 56 of the flexible resin film is stacked (Step S 13 ). Further thereon, the circuit layer of the pixel array part 4 , the OLED layer and the like are formed in the display area 46 , whereas the wiring 50 , the terminal 52 and the like are formed in the non-display area 48 , and the cover layer 58 is formed thereon (Step S 14 ).
[0050] After the main structure of the element substrate 42 such as the pixel array part 4 and the wiring 50 is formed on the base member 56 in Step S 14 , the dam material 74 (seal part) having a thickness corresponding to the height difference between the position of the rib 92 and an area arranged opposite the end part 64 of the counter substrate 44 at the boundary between the display area 46 and the non-display area 48 is formed in this area (Step S 15 ). Thus, the first substrate layer 200 is formed on the surface of the support plate 90 .
[0051] Next, the second substrate layer forming process will be described. In this process, as in the first substrate layer forming process, a support plate 96 is prepared (Step S 20 ), and a sacrificial layer (not illustrated) and the barrier layer 70 are stacked thereon in order (Step S 21 ). Also, a ridge-like second rib 98 is formed using a covalently or ionically bonding inorganic material, on the barrier layer 70 along the edge of the counter substrate 44 (Step S 22 ). The rib 98 can be formed using a technique and material that are basically similar to those of the rib 92 . The thickness (height) of the rib 98 is set to be basically greater than the thickness of the multilayer structure subsequently formed in the area (counter area part) surrounded by the rib 98 . The same material as the barrier layer 62 may be used for the barrier layer 70 , and the same material as the material used at the time of forming the first substrate layer may be used for the sacrificial layer.
[0052] Also, in FIG. 6 , since the counter substrate 44 is stacked on the display area 46 of the element substrate 42 , the counter substrates 44 next to each other in the direction of width are in contact with each other at the edge, similarly to the element substrates 42 , and these counter substrates 44 share the rib 98 provided along the side in the direction of length, whereas the rib 98 provided along the side in the direction of width is not shared between the counter substrates 44 .
[0053] In the area surrounded by the rib 98 , the base member 66 of the flexible resin film is stacked (Step S 23 ), and the color filter, the barrier layer and the like forming the color filter layer 68 are formed further thereon (Step S 24 ). Thus, the second substrate layer 202 is formed on the surface of the support plate 96 . As described above, the same material as the base member 56 , for example, can be used for the base member 66 .
[0054] FIG. 4 shows the first substrate layer 200 and the second substrate layer 202 produced by the above processes. Next, the process of assembling these substrate layers into the display panel 40 . The counter area part of the second substrate layer 202 , that is, the surface of the area surrounded by the rib 98 , is a recess part by having the rib 98 formed to be higher than the counter area part. This recess part is filled with the filler 72 , using a dispenser or the like (Step S 30 ). Then, for example, the support plate 96 is horizontally placed, with the surface where the second substrate layer 202 is formed facing upward, and the support plate 90 is overlaid on the support plate 96 , with the surface where the first substrate layer 200 is formed facing downward. Then, the first substrate layer 200 and the second substrate layer 202 are bonded together into the state shown in FIG. 5 (Step S 31 ).
[0055] Here, the filler 72 may fill the gap between the two substrate layers when the first substrate layer 200 and the second substrate layer 202 are bonded together. That is, the filler 72 need not necessarily be spread on the entire surface of the recess part at the stage of Step S 30 . For example, the filler 72 may be scattered inside the recess part in Step S 30 , and the filter 72 can be evenly spread in the gap when the two substrate layers are bonded in a vacuum.
[0056] Also, a filler 100 may be scattered in the area opposite the margin area 94 of the first substrate layer 200 , of the second substrate layer 202 , and may be used as a spacer for maintaining the gap between the two substrate layers at the part corresponding to the non-display area 48 of the element substrate 42 .
[0057] After the fillers 72 , 100 are hardened, the joined body of the substrate layers 200 , 202 is divided together with the support plates 90 , 96 into the respective display panels 40 by using the scribe and break technique (Step S 32 ). Specifically, each of the support plates 90 , 96 is scribed and the substrate layers are flexed and broken together with the support plates.
[0058] Scribe lines are formed along the ribs 92 , 98 . Particularly, at the part where the rib is shared among the element substrates 42 adjacent to each other in the first substrate layer 200 , or the counter substrates 44 adjacent to each other in the second substrate layer 202 , the scribe line is set within the width of the rib, so that the rib is left on both adjacent substrates after breaking. In this embodiment, such a shared part of the rib is the part extending in the direction of length, of the ribs 92 , 98 shown in FIG. 6 .
[0059] Meanwhile, at the part of the rib that is not shared among the element substrates 42 adjacent to each other in the first substrate layer 200 or the counter substrates 44 adjacent to each other in the second substrate layer 202 , the scribe line may be set along the edge on the side of the rib that is not adjacent to the element substrate 42 or the counter substrate 44 , so that, at this part, the rib is left in its full width on the adjacent substrate. In this embodiment, such a non-shared part of the rib is the part extending in the direction of width, of the ribs 92 , 98 shown in FIG. 6 . However, the scribe line is set within the width of the rib at this part as well, thus achieving a narrower frame. Specifically, scribe lines are set at the positions α 1 , α 2 on the first substrate layer 200 and the positions β 1 , β 2 on the second substrate layer 202 shown in FIG. 5 , and the substrate layers are then broken.
[0060] The ribs 92 , 98 after the breaking form the outer peripheral end parts 60 , 64 of the element substrate 42 and the counter substrate 44 , respectively.
[0061] Here, the dam material 74 is formed in the area facing a part of a rib 98 a shown in FIG. 5 . The rib 98 a is the rib 98 situated at the boundary between the display area 46 and the non-display area 48 , and the part of the rib 98 a belongs to the counter substrate 44 after the braking. That is, in the case where the scribe line is set within the width of the rib 98 a as described above, the forming area for the dam material 74 and the position of the scribe line are adjusted so that the dame material 74 will not protrude to the outside from the position β 2 of the scribe line. If the dam material 74 is laid across the break position, the dame material 74 may not be divided, or a part 102 that should be removed by the division, of the second substrate layer 202 , may remain attached to the element substrate 42 even after the division. On the other hand, if the dam material 74 is held on the inside from the position β 2 of the scribe line, this part 102 can be easily removed by breaking.
[0062] After the breaking, the cover layer 58 and the like stacked on the terminal 52 are removed, exposing the terminal 52 . Then, the process of connecting the FPC 54 to the terminal 52 , or the like, is carried out.
[0063] Subsequently, the support plates 90 , 96 are separated from the joined body of the element substrate 42 and the counter substrate 44 divided for each display panel 40 by the breaking (Step S 33 ). For the separation of the support plates, methods such as evaporating the sacrificial layers between the barrier layers 62 , 70 and the support plates 90 , 96 by laser ablation, or dissolving the sacrificial layers by etching, may be used. After separating the support plates, the protection films 76 , 78 are stuck to the back sides of the element substrate 42 and the counter substrate 44 . Thus, the structure of the display panel 40 shown in FIG. 2 is basically achieved.
[0064] In the embodiment, the case of an organic EL display device is illustrated as a disclosed example of the display device. However, as other application examples, any flat panel display devices can be employed, such as a liquid crystal display device, other types of self-light-emitting display device, electronic paper display device having an electrophoretic element or the like, and quantum dot display device. Also, as a matter of course, display devices of medium and small sizes to large size can be used without any particular limitation.
[0065] A person skilled in the art can readily think of various changes and modifications within the scope of the technical idea of the invention, and such changes and modifications should be understood as falling within the scope of the invention. For example, the addition or deletion of a component, or a design change suitably made to the foregoing embodiment by a person skilled in the art, or the addition or omission of a process, or a condition change in the embodiment is included in the scope of the invention as long as such change or the like includes the spirit of the invention.
[0066] Also, as a matter of course, other advantageous effects that may be achieved by the configurations described in the embodiment should be understood as being achieved by the invention if those effects are clear from the specification or can be readily thought of by a person skilled in the art.
[0067] While there have been described what are at present considered to be certain embodiments of the invention, it will be understood that various modifications may be made thereto, and it is intended that the appended claims cover all such modifications as fall within the true spirit and scope of the invention. | Simple and high-precision processing, and narrowing of the frame are to be facilitated at the time of preparing display panels by multiple formation. After bonding a first substrate layer in which a plurality of element substrates is formed on a support plate and a second substrate layer in which a plurality of counter substrates is formed on a support plate, these substrate layers are divided into a plurality of display panels. Ridge-like ribs of a covalently or ionically bonding inorganic material are formed along edges of the element substrate and the counter substrate. The dividing includes scribing the support plates along the ribs, and flexing and breaking the support plates. | 36,672 |
The present application claims priority from U.S. Provisional patent application No. 60/406,661, filed Aug. 29, 2002.
FIELD OF THE INVENTION
The present invention relates to improving the luminance and the operating stability of phosphors used for full color ac electroluminescent displays employing thick film dielectric layers with a high dielectric constant. More specifically, the invention relates to an improved thin film fine grained zinc sulfide phosphor in combination with a structure and/or substance to minimize or prevent reaction of the fine grained phosphor with oxygen for use in electroluminescent displays.
BACKGROUND OF THE INVENTION
Thick film dielectric structures as exemplified by U.S. Pat. No. 5,432,015 are known and exhibit superior characteristics to that of traditional TFEL displays. High performance red, green and blue phosphor materials have been developed for use with thick film dielectric structures to provide increased luminance performance. These phosphor materials include europium activated barium thioaluminate based materials for blue emission, terbium activated zinc sulfide, manganese activated magnesium zinc sulfide or europium activated calcium thioaluminate based materials for green emission, as well as traditional manganese activated zinc sulfide that can be appropriately filtered for red emission.
The thin film phosphor materials used for red, green and blue sub-pixels must be patterned using photolithographic techniques employing solvent solutions for high resolution displays. Traces of these solutions remaining in the display following photolithographic processing together with reaction of moisture or oxygen present in the processing environment may react chemically with certain phosphor materials that are sensitive to oxidation or hydrolysis reactions to cause performance degradation of the completed display. Continued chemical reactions during operation of the display may cause continued performance degradation thereby shortening the life of the display.
To overcome such performance degradation problems, researchers have proposed the use of various materials in conjunction with phosphor materials including zinc sulfide rare earth metal activated phosphors as disclosed for example in U.S. Pat. Nos. 6,048,616 and 6,379,583.
Ihara et al., ( Journal of the Electrochemical Society 149 (2002) pp H72-H75) discloses the use of glass to encapsulate nanocrystalline terbium activated zinc sulfide grains. Such encapsulated nanocrystalline grains led to substantially increased photoluminescence and cathodoluminescence as compared to bulk terbium activated zinc sulfide that was attributed to an increase in the transition probability for the decay of the terbium atom from its excited state. The glass coating prevented loss of sulfur and terbium relative to the zinc content of the particles under electron bombardment, whereas uncoated particles with the same diameter showed a significant loss of sulfur and some loss of terbium under the same conditions. The sulfur loss was due to displacement of sulfur from the zinc sulfide by oxygen. However, this reference teaches that the glass coating method is not applicable to the coating of bulk materials such as deposited films and therefore the use of the coated powders for electroluminescent applications was not considered where the factors controlling luminance are different than they are for photoluminescence or cathodoluminescence. Also, a reduction in the grain size of manganese activated zinc sulfide phosphor films in electroluminescence applications did not facilitate an improvement in luminance, but rather decreased the luminance, showing that a reduction in grain size does not necessarily lead to increased luminance.
Mikami et al., (Proceedings of the 6 th International Conference on the Science and Technology of Display Phosphors (2000) pp. 61-4) disclose the use of sputtered silicon nitride layers to encapsulate a terbium activated zinc magnesium sulfide thin film phosphor layer in an electroluminescent device to improve the emission spectrum for use as a green phosphor. Luminosity or luminance stability of the device was not addressed.
J. Ohwaki et al., (Review of the Electrical Communications laboratories Vol. 35, 1987) disclose the use of chemical vapour deposition to deposit silicon nitride on an electron beam deposited terbium activated zinc sulfide phosphor film to improve its luminance stability. The silicon nitride layer was to provide a barrier to prevent moisture incursion into the conventional type of zinc sulfide phosphor. Further, chemical vapour deposition processes are difficult to adapt to large area electroluminescent displays for television and other large format display applications and suffer cost and safety disadvantages associated with the handling of volatile precursor chemicals and remediation of effluent gases required for the processes.
U.S. Pat. No. 4,188,565 discloses the use of oxygen-containing insulator silicon nitride layers for use with a manganese activated zinc sulfide phosphor where the oxygen content in the silicon nitride is between 0.1 and 10 mole percent. It is taught in this patent that silicon nitride that does not contain oxygen is unsatisfactory because it does not form a sufficiently strong bond with the phosphor material to prevent delamination. The above noted patent further teaches deposition of the oxygen doped silicon nitride by the use of a sputtering process in a low-pressure atmosphere of nitrogen or a nitrogen-argon mixture containing nitrous oxide. A second insulator layer in combination with the oxygen doped silicon nitride layer is also used to prevent degradation of the phosphor material due to reaction with ambient moisture.
U.S. Pat. No. 4,721,631 discloses deposition of a silicon nitride layer or a silicon oxynitride layer on top of a manganese activated zinc sulfide phosphor film using a plasma chemical vapour deposition method. In this method the process gas for the deposition includes nitrogen and silane rather than ammonia and silane in order to exclude hydrogen from the process since hydrogen can react with sulfur bearing phosphor materials to form hydrogen sulfide, thereby degrading the phosphor performance. It is disclosed that silicon nitride layers deposited using the ammonia free plasma chemical vapour deposition process enable equivalent performance results with manganese activated zinc sulfide phosphors to those obtained with sputtered silicon nitride layers, whereas silicon nitride layers deposited using ammonia yield inferior results.
U.S. Pat. No. 4,880,661 discloses that a manganese-activated zinc sulfide phosphor film cannot successfully be deposited on top of a silicon nitride film using chemical vapour deposition due to its hydrogen concentration. The hydrogen migrates into the phosphor during thermal annealing of the deposited phosphor, causing degradation by loss of sulfur due to reaction with the hydrogen.
U.S. Pat. No. 4,897,319 discloses an electroluminescent device with a double-stack insulator on either side of a manganese-activated zinc sulfide phosphor layer to improve the luminance and energy efficiency of the device. One of the stack members is silicon oxynitride and the other is barium tantalate. The order of the members are reversed on the two sides with the silicon oxynitride layer in contact with the phosphor film on one side and the barium tantalate oxide layer in contact with the phosphor on the opposite side.
U.S. Pat. No. 5,314,759 discloses an electroluminescent display that includes a terbium activated zinc sulfide phosphor layer deposited by Atomic Layer Epitaxy (ALE) and a layer of samarium doped zinc aluminum oxide.
U.S. Pat. No. 5,496,597 discloses a method for making a multilayer alkaline-earth sulfide-metal oxide structure for electroluminescent displays. The phosphor layer has dielectric layers on each side composed of various materials including aluminum oxide.
U.S. Pat. No. 5,598,059 discloses various phosphors including zinc sulfide doped with terbium and having insulating layers of various materials including aluminum oxide.
U.S. Pat. No. 5,602,445 discloses various phosphors with layered construction and having insulating and buffer layers about the phosphor. In one aspect, zinc sulfide is used to sandwich a calcium chloride or strontium chloride rare earth activated phosphor.
U.S. Pat. No. 5,644,190 discloses the use of insulator layers of silicon oxide on both sides of phosphor layers of various materials including manganese activated zinc gallium oxide and zinc cadmium sulfide activated with silver and indium oxide.
WO 00/70917 discloses an electroluminescent laminate that includes a rate earth activated zinc sulfide material having a diffusion barrier layer of zinc sulfide.
While the aforementioned references and patents may teach the use of a conventional large grained rare earth activated zinc sulfide phosphor with certain types of “barrier” or “insulator” materials” for the purpose of preventing reaction of the phosphor with water from the ambient environment or some other “stabilizing” type function, there remains a need to provide an improved zinc sulfide rare earth activated phosphor that has both improved luminance and a long operating life with minimal degradation.
SUMMARY OF THE INVENTION
The present invention is directed to a thick film electroluminescent device employing a thin film zinc sulfide phosphor doped with a rare earth activator species that has an improved luminance and a long operating life with minimal luminance degradation. Conventional teachings in EL technology utilize phosphors with a large grain size in order to achieve good performance. In contrast, in the present invention an improved rare earth activated zinc sulfide phosphor is achieved by making the zinc sulfide thin film phosphor fine grained. The use of the fine grained zinc sulfide phosphor may be combined with a structure and/or substance to minimize or prevent reaction of the fine grained phosphor with oxygen within a thick film electroluminescent display.
In aspects, a structure or substance suitable for use with the fine grained phosphor may be selected from: interface modifying layers on one or both sides of the phosphor film to improve the stability of the interface between the phosphor film and the rest of the device structure; a hermetic enclosure for the electroluminescent display; an oxygen getter incorporated into the display; and any combination thereof including having all of the structures and substances present together in a single display.
Zinc sulfide based phosphor films are susceptible to degradation due to incorporation of oxygen into the film, either by replacement of sulfur by oxygen in the crystal lattice, or by incorporation of oxygen into the grain boundaries. In fact, the reaction rate with oxygen is increased if the grain size is small or if the zinc sulfide crystal lattice contains a high density of crystal defects. The luminance of zinc sulfide based sulfide phosphor materials is adversely affected by oxygen incorporation. The source of the oxygen may be the internal structure of the display device outside of the phosphor film, or it may be the ambient environment. The rate of oxygen incorporation may be accelerated by the presence of water in the structure. The rate of reaction is typically higher if the crystal grain size is smaller, due in part to the ability of oxygen to diffuse within the film along grain boundaries much more quickly than it can diffuse through the crystal lattice of the individual grains.
To overcome such difficulties, the Applicant's have developed thin film zinc sulfide phosphors doped with rare earth activator species where the phosphor material is fine grained with a preferred morphology and with a preferred crystal structure to improve luminance. The use of such fine grained phosphors may be combined with a structure and/or substance to minimize or prevent reaction of the fine grained phosphor with oxygen.
In one aspect, interface modifying layers may be employed to help limit the rate at which oxygen can react with the phosphor material and facilitates the use of a fine grained phosphor. The interface modifying layer is preferably oxygen-free and hydrogen-free, although it may contain oxygen that is sufficiently tightly bonded that it cannot react with the adjacent phosphor material.
In another aspect, a hermetic enclosure may be provided to minimize exposure of the fine grained phosphor material to oxygen. Such an enclosure may comprise an optically transparent cover plate disposed over the laminated structure comprising the phosphor layer deposited onto the device substrate with a sealing bead between the substrate and the cover plate beyond the perimeter of the laminated structure. The sealing bead may comprise a glass frit or polymeric material as is known to those of skill in the art. Alternatively it may be an oxygen-impermeable sealing layer deposited over, and extending everywhere beyond the perimeter of the laminated structure to prevent exposure of the phosphor to oxygen.
In a further aspect, an oxygen getter may be introduced into the display to remove traces of oxygen. Getter materials are known to those of skill in the art. A getter should be selected that has a greater affinity for oxygen than the phosphor material during the operational lifetime of the electroluminescent device. The getter should be positioned within the hermetic enclosure to capture any residual oxygen within the enclosure or that may permeate into the enclosure during the display life. It is preferable that the getter be positioned so that it is not directly incorporated into or in contact with the fine grained phosphor material.
According to an aspect of the present invention is an improved phosphor for an electroluminescent display, said phosphor comprising;
a thin fine grained rare earth metal activated zinc sulfide phosphor material.
According to another aspect of the present invention is an improved phosphor for an electroluminescent display, said phosphor comprising;
a thin fine grained rare earth metal activated zinc sulfide phosphor material, wherein said phosphor has a crystal grain dimension of up to about 50 nm.
According to another aspect of the present invention is an improved phosphor for an electroluminescent display, said phosphor comprising;
a thin fine grained rare earth metal activated zinc sulfide phosphor material used in combination with a structure or substance to minimize or prevent reaction of said fine grained phosphor with oxygen.
According to still another aspect of the present invention is a thick film dielectric electroluminescent device comprising;
a thin film fine grained rare earth metal activated zinc sulfide phosphor; and a structure and/or substance to minimize or prevent reaction of the fine grained phosphor with oxygen, wherein said structure or substance comprises one or more of;
i) interface modifying layers on one or both sides of the phosphor film to improve the stability of the interface between the phosphor film and the rest of the device;
ii) a hermetic enclosure for the electroluminescent device; and
iii) an oxygen getter incorporated into the device.
According to yet another aspect of the invention is a thick film dielectric electroluminescent device comprising;
a thin phosphor layer of formula ZnS:Re, wherein said phosphor layer has a crystal grain size of up to about 50 nm and Re is selected from terbium and europium; and a structure and/or substance to minimize or prevent reaction of the fine grained phosphor with oxygen, wherein said structure or substance comprises one or more of;
i) interface modifying layers on one or both sides of the phosphor film to improve the stability of the interface between the phosphor film and the rest of the device;
ii) a hermetic enclosure for the electroluminescent device; and
iii) an oxygen getter incorporated into the device.
According to yet another aspect of the present invention is an improved phosphor structure for an electroluminescent display, said structure comprising;
a thin fine-grained rare earth metal activated zinc sulfide phosphor layer; and an interface modifying layer adjacent one or both sides of said phosphor layer.
According to an aspect of the present invention is an improved phosphor structure for an electroluminescent display, said structure comprising;
a thin phosphor layer of formula ZnS:Re, wherein said phosphor layer has a crystal grain size of up to about 50 nm and Re is selected from terbium and europium; and an interface modifying layer adjacent one or both sides of said phosphor layer wherein said modifying layer is selected from the group consisting of pure zinc sulfide, hydroxyl ion free alumina (Al 2 O 3 ) or alumina containing hydroxyl ions at a concentration sufficiently low that it does not contribute to phosphor degradation, aluminum nitride, silicon nitride containing no oxygen (Si 3 N 4 ) and silicon nitride with a sufficiently low oxygen content that the oxygen is sufficiently tightly bound so as not to contribute to phosphor degradation.
According to an aspect of the present invention is an improved phosphor structure for an electroluminescent display, said structure comprising;
a thin phosphor layer of formula ZnS:Re, wherein said phosphor layer has a sphalerite crystal structure of grain size of about 20 to about 50 nm and Re is selected from terbium and europium; and an interface modifying layer adjacent one or both sides of said phosphor layer wherein said modifying layer is selected from the group consisting of pure zinc sulfide, hydroxyl ion free alumina (Al 2 O 3 ) or alumina containing hydroxyl ions at a concentration sufficiently low that it does not contribute to phosphor degradation, aluminum nitride, silicon nitride containing no oxygen (Si 3 N 4 ) and silicon nitride with a sufficiently low oxygen content that the oxygen is sufficiently tightly bound so as not to contribute to phosphor degradation.
According to yet another aspect of the present invention is an improved phosphor structure for an electroluminescent display, said structure comprising;
a thin phosphor layer of formula ZnS:Tb, wherein said phosphor layer has a crystal grain size of about 20 nm to about 50 nm; and an interface modifying layer adjacent one or both sides of said phosphor layer wherein said modifying layer is pure zinc sulfide.
According to another aspect of the present invention is a thick film dielectric electroluminescent device comprising;
a thin fine-grained rare earth metal activated zinc sulfide phosphor layer; and an interface modifying layer adjacent one or both sides of said phosphor layer.
According to yet another aspect of the present invention is a method for making a fine grained rare earth metal activated zinc sulfide phosphor film, said method comprising;
depositing said film onto a substrate using a sputtering process in an atmosphere comprising argon at a working pressure in the range of about 0.5 to 5×10 −2 torr and an oxygen partial pressure of less than about 0.05 of the working pressure, said film substrate maintained at a temperature between ambient temperature and about 300° C., at a deposition rate in the range of about 5 to 100 Angstroms per second, wherein the atomic ratio of the rare earth metal to zinc in the source material is in the range of about 0.5 to 2 percent.
In aspects of the method, the oxygen partial pressure is preferably less than about 0.02 percent of the working pressure; the film substrate is maintained at a temperature of about between ambient and 200° C.; the working pressure is in the range of about 1 to 3×10 −2 torr, the deposition rate is in the range of about 5 to 100 Angstroms per second, more preferably in the range of about 5 to 50 Angstroms per second and more preferably in the range of about 10 to 30 Angstroms per second; and the atomic ratio of the rare earth element to zinc in the source material is in the range of about 0.5 to 2 percent.
According to still a further aspect of the present invention is a method for stabilizing a fine grained rare earth metal activated zinc sulfide phosphor, said method comprising;
providing an interface modifying layer adjacent one or both sides of said phosphor.
According to yet another aspect of the invention is a method for stabilizing a fine grained rare earth metal activated zinc sulfide phosphor within a thick film dielectric electroluminescent device, said method comprising;
providing a structure and/or substance to minimize or prevent reaction of the fine grained phosphor with oxygen, wherein said structure or substance comprises one or more of;
i) interface modifying layers on one or both sides of the phosphor film to improve the stability of the interface between the phosphor film and the rest of the device;
ii) a hermetic enclosure for the electroluminescent device; and
iii) an oxygen getter incorporated into the device.
Other features and advantages of the present invention will become apparent from the following detailed description. It should be understood, however, that the detailed description and the specific examples while indicating embodiments of the invention are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from said detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given herein and from the accompanying drawings, which are given by way of illustration only and do not limit the intended scope of the invention.
FIG. 1 shows a schematic drawing of the cross section of a thick dielectric electroluminescent device showing the position of silicon nitride layers of the present invention.
FIG. 2 are graphs showing the luminance versus cumulative operating time for electroluminescent devices having an electron beam-deposited terbium activated zinc sulfide phosphor subject to different annealing conditions.
FIG. 3 is a scanning electron micrograph of a cross section of an electron beam evaporated terbium activated zinc sulfide phosphor film in an electroluminescent device.
FIG. 4 is a graph showing the luminance versus cumulative operating time for an electroluminescent device having a fine-grained sputtered terbium activated zinc sulfide phosphor
FIG. 5 is a scanning electron micrograph of a cross section of a fine-grained sputtered terbium activated zinc sulfide phosphor film in an electroluminescent device.
FIG. 6 is a graph comparing the luminance versus cumulative operating time for an electroluminescent device having a fine-grained sputtered terbium activated phosphor film in contact with an undoped zinc sulfide layer against that of a similar device without the undoped zinc sulfide layer.
FIG. 7 is a graph comparing the luminance versus cumulative operating time for an electroluminescent device having a fine grained sputtered terbium activated phosphor film doped with oxygen against that of a similar device that was not doped with oxygen.
FIG. 8 is a graph comparing the luminance versus cumulative operating time for an electroluminescent device having a fine-grained sputtered terbium activated phosphor film in contact with a silicon nitride layer against that of a similar device without the silicon nitride layer.
FIG. 9 is a graph comparing the luminance versus cumulative operating time for an electroluminescent device having a fine-grained sputtered terbium activated phosphor film in contact with an alumina layer deposited using atomic layer chemical vapour deposition.
DETAILED DESCRIPTION OF THE INVENTION
The present invention is a fine-grained zinc sulfide thin film phosphor layer in a thick film electroluminescent device where additionally a structure and/or substance is provided to minimize or prevent reaction of the fine grained phosphor with oxygen. The structure or substance may be selected from one or more of: interface modifying layers on one or both sides of the phosphor film to improve the stability of the interface between the phosphor film and the rest of the device; a hermetic enclosure for the electroluminescent device; and an oxygen getter incorporated into the device. It is understood by one of skill in the art that the fine grained zinc sulfide phosphor of the invention may be incorporated into an electroluminescent device additionally having one or all of the aforementioned structures or devices.
In one preferred aspect, the fine grained thin film zinc sulfide phosphor film is in contact at one or both surfaces with an interface modifying layer that improves the electrical and chemical stability of the phosphor film and its interface with the rest of the electroluminescent device. The novel combination of fine grained phosphor with a preferred morphology and with a preferred crystal structure with one or more layers of an interface modifying layer adjacent the phosphor, acts to stabilize the phosphor from degradation and provide enhanced luminance and longer operational life of the phosphor within an electroluminescent device.
The present invention is particularly applicable to electroluminescent devices employing a thick dielectric layer having a high dielectric constant dielectric layer wherein the thick dielectric material is a composite material comprising two or more oxide compounds that may evolve chemical species that are deleterious to phosphor performance in response to thermal processing or device operation and wherein the surface of the thick dielectric is rough on the scale of the phosphor thickness resulting in cracks or pinholes through the device structure and contains voids that may contain or absorb such species, thus contributing to a loss of luminance and operating efficiency over the operating life of the device.
FIG. 1 shows a schematic drawing of the cross section of an electroluminescent device of the present invention generally indicated by reference numeral 10 . The device 10 has a substrate 12 with a metal conductor layer 14 (ie. gold), a thick film dielectric layer 16 (i.e. PMT-PT) and a smoothing layer 18 (i.e. lead zirconate titanate) thereon. A variety of substrates may be used, as will be understood by persons skilled in the art. The preferred substrate is a substrate that is opaque in the visible and infrared regions of the electromagnetic spectrum. In particular, the substrate is a thick film dielectric layer on a ceramic substrate. Examples of such substrates include alumina, and metal ceramic composites. An interface modifying layer 18 is shown to be present adjacent the phosphor layer 20 . While the interface modifying layer 18 is shown on both sides of the phosphor, it is understood that only one such layer either above or below the phosphor may be used. A thin film dielectric layer 22 and then an ITO transport electrode 24 are present above the phosphor. A hermetic enclosure 26 is shown disposed over the laminated structure which is enclosed by a sealing bead 28 .
The interface modifying layer helps to minimize migration of oxygen into the phosphor material during device operation to avoid performance degradation. The interface modifying layer, in addition to inhibiting the migration of oxygen, helps to minimize migration of water or other deleterious chemical species originating from the external environment into the phosphor to cause a reduction in luminance. Similarly, a hermetic enclosure and oxygen getter both act to minimize exposure of the phosphor material to oxygen.
The present invention is particularly directed towards improving the luminosity and operating life of rare earth-activated zinc sulfide phosphor materials, or zinc sulfide phosphors doped with another activator whose radiative efficiency can be improved by reducing the grain size of the host crystal lattice. While not being bound to any particular theory, the increase in phosphor stability and luminance may be related to an increase in the radiative transition probability for the activator species in question due to a change in its local environment within the host lattice, for example by a slight shift in the atomic levels localized on the activator atom relative to the electronic band gap of the zinc sulfide host lattice. If the energy difference between one or other of these electronic energy levels and the electron states in the top of the valence band or bottom of the conduction band is reduced by sufficiently reducing the grain size such that the electronic band structure deviates to a degree from that for bulk zinc sulfide, then spectroscopic selection rules that would normally prevent or nearly prevent the optical transition in question may be partially removed, thus increasing the radiative transition probability. This may in turn decrease a tendency for non-radiative relaxation of the activator species (such that light would not be emitted during the relaxation process). This model is supported by the experimental observation that the radiative decay time for photoexcitation of terbium as an activator species is substantially reduced if the host grain size is reduced to about 50 nm. Some activator species such as manganese in zinc sulfide are relatively unaffected by a decrease in the crystal grain size of the host material, and this may have to do with the positioning of the manganese electron states with respect to the zinc sulfide band gap. Also activator species typified by manganese may be relatively unaffected by the substitution of oxygen of sulfur in the immediate environment of the host lattice. The pronounced reduction in the luminance of terbium activated zinc sulfide with the substitution of oxygen for sulfur in the host lattice is possibly due to the high affinity of terbium for oxygen. Sulfur can be displaced by oxygen in the zinc sulfide host material. Such reactions are expected to be enhanced if the grain size is small.
The zinc sulfide phosphors for the invention can be represented by the formula ZnS:RE where RE is a rare earth metal selected from the group consisting of terbium and europium. Terbium is most preferred for use in the invention. The atomic ratio of terbium or europium to zinc is preferably in the range of about 0.005 to about 0.02 and more preferably in the range of about 0.01 to 0.02.
The zinc sulfide phosphors of the invention are fine grained rare earth-activated zinc sulfide phosphor films wherein the crystal structure of the zinc sulfide comprises the zincblende (sphalerite) crystal structure with the ( 111 ) crystallographic direction substantially aligned in a direction perpendicular to the plane of the film and wherein an interface modifying film is provided in contact with one or both surfaces of the film. The fine grained phosphor is preferably deposited using a sputtering process in an atmosphere comprising argon or another inert gas and optionally containing a minor concentration of hydrogen sulfide or another sulfur bearing vapour to minimize oxygen incorporation into the phosphorfilm.
The crystal grains of the zinc sulfide phosphor are columnar in shape with the long dimension of the columns extending substantially across the thickness of the phosphor film in a direction perpendicular to the film and where the width of the columnar grains is less than about 50 nm, and wherein the phosphor film is in contact at one or both of its surfaces with an interface modifying layer for the purpose of minimizing performance degradation of the phosphor material during device operation. The grain size is defined as the dimension in a direction perpendicular to the column axis when the grains have a columnar shape. It is understood by those of skill in the art that the crystal grain dimension can be of any size up to about 50 nm and any ranges thereof, such as from but not limited to about 20 nm to about 50 nm, about 30 nm to about 50 nm and about 40 nm to about 50 nm. The thickness of the zinc phosphor layer is about 0.5 to about 1.0 μm.
The phosphor of the present invention may be deposited onto a suitable substrate by a variety of known methods such as for example, sputtering, electron beam deposition and chemical vapour deposition. Sputtering is the preferred method to deposit the fine grained phosphor. Sputtering is conducted in an atmosphere comprising argon at a working pressure in the range of about 0.5 to 5×10 −2 torr and an oxygen partial pressure of less than about 0.05 percent of the working pressure. The film substrate is maintained at a temperature between ambient temperature and about 300° C. at a deposition rate in the range of about 5 to 100 Angstroms per second. The atomic ratio of the rare earth metal to zinc in the source material is about 0.5 to about 2 percent to provide the desired ratio in the deposited film in the range of about 0.005 to 0.02 and preferably in the range of about 0.01 to 0.02.
It is understood by one of skill in the art that in aspects of the method, the oxygen partial pressure is preferably less than about 0.02 percent of the working pressure; the working pressure is in the range of about 1 to 3×10 −2 torr, the film substrate is maintained at a temperature of about between ambient and 200® C.; the deposition rate is in the range of about 15 to 50 Angstroms per second, more preferably 20 to 30 Angstroms per second; and the atomic ratio of the rare earth element to zinc in the source material in the range of about 0.8 to 1.2 percent such to provide a deposited film with an atomic ratio of rare earth element to zinc in the range of 0.005 to 0.02.
The provision of a fine grained and defined crystal structure for the zinc sulfide phosphor is dependent on a variety of conditions of the deposition process such as for example: substrate nature, substrate temperature, deposition rate, type and concentration of dopant, pressure and composition of vacuum environment. In one aspect of the invention the rate at which oxygen can diffuse within the phosphor layer is limited by minimizing the concentration of sulfur vacancies in the zinc sulfide phosphor material and minimizing the oxygen concentration in the phosphor layer after fabrication of the electroluminescent device. A means to limit the oxygen and sulfur vacancy concentration is to deposit the phosphor layer in a low-pressure sulfur-containing atmosphere but at a pressure sufficient to ensure that the deposited phosphor material is not sulfur-deficient. Conditions to ensure sulfur sufficiency are well known in the art. Further, one of skill in the art could readily examine the deposited phosphor film and confirm by methods such as x-ray diffraction analysis that the film was in fact fine grained in accordance with the present invention.
The effect of oxygen in decreasing the luminance of terbium activated zinc sulfide thin phosphor films has been demonstrated by comparing the performance of films sputtered in an argon atmosphere to that of films sputtered in an atmosphere comprising 0.1% oxygen in argon. The luminance of the latter films in thick dielectric electroluminescent devices was shown to be substantially, lower than that of the former films.
The interface modifying layer(s) of the invention can comprise a variety of materials such as for example pure zinc sulfide, hydroxyl ion free alumina, aluminum nitride, silicon nitride and aluminum oxide that has been deposited using atomic layer epitaxy wherein the hydroxyl ions contained within the oxide layer is maintained at a concentration sufficiently low that it does not contribute to phosphor degradation. Preferred materials for use as an interface modifying layer are pure undoped zinc sulfide and silicon nitride.
The thickness of the modifying layer or layers is chosen to be sufficient to prevent oxygen incorporation into the phosphor film but not too thick that the voltage drop across the modifying and phosphor contributes excessively to an increased operation voltage for the display. If the modifying layer is too thin, it may not be continuous and therefore may not prevent oxygen incorporation into the phosphor layer. Further, diffusion of oxygen through the film along grain boundaries is faster if the film is thinner. Generally, if the relative dielectric constant of the modifying layer is in the range of about 7 to 10, a thickness in the range of about 40 to 60 nm is suitable. One skilled in the art may readily optimize the thickness by achieving a practical trade-off between the inhibiting reaction of oxygen with the phosphor and minimizing the operating voltage for the device.
In one aspect of the invention, sputtering is the preferred method for deposition of a silicon nitride interface modifying layer phosphor. The deposition rate is controlled by adjusting the rf power to the target. The deposition rate being adjusted to provide a dense non-porous coating to provide an effective oxygen barrier at the desired thickness. Typically a deposition rate in the range of about 4 to 6 Angstroms per second is suitable. The temperature of the substrate during deposition is maintained close to ambient temperature up to about 200° C.
In the case of silicon nitride (that does not contain oxygen), the film composition of the silicon nitride should be controlled in order that it adhere well to the phosphor layer. Specifically, the film should not contain nitrogen beyond the stoichiometric ratio for Si 3 N 4 . Excess nitrogen has been found to cause internal stress to accumulate within the film leading to delamination. It has been found that if the reactive sputtering is carried out using a silicon nitride target in a low pressure nitrogen atmosphere, the composition of the film can be controlled so that the film comprises a composite film comprising stoichiometric silicon nitride and elemental silicon. Provided that the silicon content is maintained at a suitably low level, the electrical resistivity of the silicon nitride film will be maintained at a suitably high value, the chemical reactivity will be suitably low and the internal stress in the film will be sufficiently low to prevent delamination of the silicon nitride film from the phosphor and other adjacent layers.
The required composition for a sputtered silicon nitride film can be achieved provided that the ratio of argon to nitrogen is within the range of about 6:1 to 2:1 and the working pressure is maintained within the range of about 8×10 −4 torr to about 6×10 −3 torr. If the ratio of argon to nitrogen is too low, the deposited film will have high internal stress and may delaminate from adjacent layers. If the ratio is too high the deposited film may be chemically reactive and have an unacceptably high electrical conductivity. These undesirable properties will arise if the silicon phase is in sufficient concentration to form a continuous silicon network through the composite film and is not encapsulated by the silicon nitride phase to prevent chemical reaction of the silicon with oxygen or other reactive species in the immediate environment.
The nitrogen content must be optimized within a preferred range by appropriate control over the deposition and subsequent thermal treatment of the silicon nitride film in a manner that is compatible, with the rest of the display structure upon which it is deposited. Typically it is found that vacuum deposition from a silicon nitride target provides satisfactory results provides that the deposition atmosphere comprises an inert atmosphere with a sufficient concentration nitrogen present to avoid silicon precipitation, but not so high as to allow excessive nitrogen to be incorporated into the film. Sputtering has been found to be particularly effective as a deposition means.
Hermetic enclosures may comprise an optically transparent cover plate disposed over the laminated structure comprising the fine grained phosphor layer deposited onto a substrate. A sealing bead is provided between the substrate and cover plate beyond the perimeter of the laminated structure. The sealing bead may comprise a glass frit or polymeric material. Alternatively, a hermetic enclosure may be an oxygen-impermeable sealing layer extending over and beyond the perimeter of the laminated structure to prevent the phosphor to oxygen exposure. Suitable oxygen-impermeable materials are known to those of skill in the art and may include but are not limited to glass and glass frit compositions.
Getter materials, in particular, oxygen getters may be used to remove traces of oxygen in the electroluminescent display. Suitable getter materials for use in the invention are known to those of skill in the art and include but are not limited to titanium and barium. It is preferred that the getter material not be directly incorporated or in contact with the phosphor layer.
The present invention is suited for use in an electroluminescent display or device as described for example in Applicant's WO 00/70917 (the disclosure of which is incorporated herein by reference). Such an electroluminescent device has a substrate on which is located row electrodes. A thick film dielectric is provided with a thin film dielectric thereon. Thin film dielectric is provided as pixel columns. The pixel columns cortain phosphors to provide the three basic colors viz. red, green and blue. In an alternate embodiment, a common thin film dielectric may be deposited over all of the pixels at one time rather than separately deposited dielectric layers over each pixel.
A variety of substrates may be used, as will be understood by persons skilled in the art. In particular, the substrate is a rigid refractory sheet that in one aspect has deposited thereon an electrically conductive film with a thick dielectric layer deposited on the conductive film. Examples of suitable refractory sheet materials include but are not limited to ceramics such as alumina, metal ceramic composites, glass ceramic materials and high temperature glass materials. Suitable electrically conductive films are known to those of skill in the art such as, but not limited to, gold and silver alloy. The thick dielectric layer comprises ferroelectric material. The thick dielectric layer may also comprise one or more thin film dielectric layers thereon.
The above disclosure generally describes the present invention. A more complete understanding can be obtained by reference to the following specific Examples. These Examples are described solely for purposes of illustration and are not intended to limit the scope of the invention. Changes in form and substitution of equivalents are contemplated as circumstances may suggest or render expedient. Although specific terms have been employed herein, such terms are intended in a descriptive sense and not for purposes of limitation.
EXAMPLE 1
Three thick dielectric electroluminescent devices incorporating thin film phosphor layers comprising fine-grained zinc sulfide activated with terbium were constructed. The thick film substrate was comprised of a 5 cm by 5 cm alumina substrate having a thickness of 0.1 cm. A gold electrode was deposited on the substrate, followed with a thick film high dielectric constant dielectric layer in accordance with the methods exemplified in Applicant's co-pending international application PCT CA00/00561 filed May 12, 2000 (the entirety of which is incorporated herein by reference). A thin film dielectric layer consisting of barium titanate, with a thickness of about 100-200 nm, was deposited on top of the thick film dielectric layer using the sol gel technique described in Applicant's co-pending U.S. patent application Ser. No. 09/761,971 filed Jan. 17, 2001 (the entirety of which is incorporated herein by reference).
A zinc sulfide phosphor film activated with about 2 atomic percent terbium added to the source material as a mixture of terbium fluoride and terbium oxide as Tb 4 O 7 was electron-beam evaporated on top of the barium titanate layer. The deposition was carried out in a chamber initially evacuated to a pressure of 5×10 −6 torr and into which hydrogen sulfide was injected at 0 to 35 sccm to maintain a hydrogen sulfide pressure of 1 to 10×10 −5 torr during the deposition. The substrate was at a temperature in the range of 100° C. to 200° C. during the deposition. The growth rate of the film was 20 to 50 Angstroms per second and the film thickness was in the range of 0.9 to 1.1 micrometers.
Next a 50 nm thick alumina layer and an indium tin oxide upper conductor film were deposited on the phosphor layer according to the methods of Applicant's co-pending international application PCT CA00/00561 (the entirety of which is incorporated herein by reference) and wherein one completed device was annealed in air at 550° C., one was annealed under nitrogen at 550° C., and the third was not annealed following deposition of the indium tin oxide and prior to testing.
The electroluminescence of the completed devices was measured by applying a 240 Hz alternating polarity square wave voltage waveform of amplitude 60 volts about the optical threshold voltage for the device. The luminance data is shown in FIG. 2 . The measured luminance can be seen from the figure to be in the range of about 300 to 400 candelas per square meter, slowly decreasing to about 250 to 350 candelas per square meter after about 5000 hours testing.
A scanning electron micrograph was obtained of a cross section of the deposited phosphor film, as shown in FIG. 3 . The majority of the crystal grains can be seen to be in the size range of 50 to 150 nm with an aspect ratio (length to width ratio) in the range of about 1:1 to 5:1. Also visible in the micrograph are the alumina layer and indium tin oxide layer above the phosphor film and a portion of the underlying dielectric layer upon which the phosphor was deposited. Chemical analysis of the film by energy dispersive x-ray analysis (EDX) showed that it was essentially stoichiometric with an atomic ratio of sulfur to zinc close to 1.
EXAMPLE 2
Two electroluminescent devices were constructed similar to that of example 1, but with a fine-grained terbium activated zinc sulfide phosphor film deposited using an rf sputtering process rather than electron beam evaporation. The film was sputtered in a chamber initially evacuated to a base pressure of 8×10 −7 torr and then filled with argon controlled to a pressure of 2.5×10 −2 torr during the sputtering process. The sputtering target was a rectangular solid of dimensions 38 cm long by 12 cm wide by 0.7 cm thick with a composition similar to that of the electron beam pellet. The film was deposited at a rate of 20 Angstroms per second to a thickness in the range of 650 to 800 nm using an rf power of 2.6 watts per cm 2 .
The devices were tested under similar conditions to those of example 1 except that the aging test was carried out at 240 Hz during the first 300 hours and then switched to 1.2 kHz to accelerate the test. The results with the time scale multiplied by 5 beyond 300 hours (the ratio of 1.2 kHz to 240 Hz) and the luminance divided by the same factor beyond 300 hours in FIG. 4 . As can be seen from this figure, the initial luminance was about 750 candelas per square meter, but decreased in an approximately linear fashion to about 400 candelas per square meter after the equivalent of about 7000 hours of testing. This example shows that the initial luminance was substantially improved over that for the electron beam deposited phosphor having a larger grain size, but, unlike the phosphors with larger grain size, the luminance decreased significantly with increasing operating time.
A scanning electron micrograph was obtained of a cross section of a similar device. The scanning electron micrograph is shown in FIG. 5 . It shows that the crystal grains of the phosphor film are substantially aligned in a direction perpendicular to the plane of the film and extend substantially across the approximate 700 nm thickness of the film. The width of the grains is mostly in the range of 20 to 50 nm. Further, x-ray diffraction analysis of the film showed the grains to consist of the zincblende crystal structure with the (111) crystallographic direction substantially perpendicular to the plane of the film. However, the film was found to be deficient in sulfur, with an atomic ratio of sulfur to zinc determined from EDX measurement of about 0.9 and with a portion of the anion deficiency made up with oxygen.
EXAMPLE 3
An electroluminescent device was constructed similar to that of example 2, but with an interface modifying layer comprising a 50 nm thick undoped zinc sulfide layer deposited using electron beam evaporation on top of the phosphor layer. The luminance versus operating time in an accelerated aging test where the voltage pulse frequency was 240 Hz for the first 300 hours and 1.2 KHz thereafter is shown in FIG. 6 , against similar data for another device without the undoped zinc sulfide. The luminance was converted to an equivalent luminance at 240 Hz, as in the previous examples. It can be seen from this figure that the initial luminance of the two devices is similar, but the rate of decrease of the luminance of the one with the undoped zinc sulfide layer is significantly lower.
This example shows the benefit of the undoped essentially pure zinc sulfide layer in stabilizing the luminance of the fine-grained terbium activated zinc sulfide phosphor layer.
EXAMPLE 4
Four electroluminescent devices similar to those of example 2, two of which had 0.1 percent oxygen added to the: argon used to maintain the atmosphere for phosphor film sputtering were constructed and tested. The comparative luminance data is shown in FIG. 7 . As can be seen from this figure, the addition of oxygen resulted in a film with significantly reduced luminance.
EXAMPLE 5
Two electroluminescent devices similar to those of example 2 were constructed, except that a 50 nm thick silicon nitride layer was sputtered onto the phosphor layer of one of the devices prior to deposition of an upper alumina dielectric layer and the indium tin oxide electrode. To deposit the silicon nitride layer a Si 3 N 4 sputtering target was employed and the sputtering atmosphere was an argon-nitrogen mixture with a ratio of argon to nitrogen of 2.3. The working pressure for sputtering was 2×10 3 torr. The argon flow rate into the sputtering chamber, during the sputtering operation was about 7 sccm. The deposition rate for the film was 5 Angstroms per second.
The luminance of the devices was measured as a function of operating time in an accelerated test at 1200 Hz with a voltage 60 volts above the initial threshold voltage. The comparative luminance data, converted to luminance at 240 hz, is shown in FIG. 8 . As with the insertion of an undoped zinc sulfide on top of the phosphor film, the silicon nitride layer had the effect of stabilizing the luminance of the device as it was operated.
EXAMPLE 6
Two electroluminescent devices similar to those of example 3 were constructed except that a 30 nm thick alumina layer was deposited using atomic layer epitaxy onto the phosphor layer. The atomic layer chemical vapour deposition (ALCVD) was carried out using tetramethyl aluminum and water as precursor reagents with the deposition substrate held at a temperature of 290° C. The use of ALCVD ensured that the deposited alumina layer was conformal to the phosphor surface and had a minimal density of pinholes or other defects that may allow oxygen infusion into the phosphor layer It also minimized the hydroxyl content of the alumina layer.
The luminance of the devices was measured as a function of operating time at 240 Hz. The luminance at 60 volts above the threshold voltage stablized at about 1050 candelas per square meter and remained at level for in excess of 500 hours. The luminance data is shown in FIG. 9, again showing the stabilizing effect of the protective layer.
EXAMPLE 7
Four devices were constructed similar to those in example 2, except that the working pressure and flow or the argon component of the working gas were varied as identified in table 1 below. The luminance at 60 volts above the threshold voltage at a frequency of 240 Hz.
TABLE 1
Device Number
Working Pressure
Argon Flow
Luminance
1
8 × 10 −3 torr
52 sccm
1315 cd/m 2
2
8 × 10 −3 torr
160 sccm
1695 cd/m 2
3
15 × 10 −3 torr
100 sccm
2320 cd/m 2
4
25 × 10 −3 torr
172 sccm
2215 cd/m 2
The phosphor grain structure of the four devices was examined by scanning electron microscopy of cross sections of the phosphor film. It was noted device #1 had a grain diameter of approximately 50 nm and did not show columnar grain shapes. Device #2 also had a grain diameter of about 50 nm and a measure of columnar structure. Devices #3 and #4 had clearly columnar grains and grain sizes of approximately 40 nm and 30 nm, respectively. This example demonstrates improved luminance associated with phosphor grain sizes of less than 50 nm achieved as the working pressure is increased above 8×10 −3 torr. It also demonstrates a weaker trend to higher luminance as the working gas flow rate is increased. This latter effect is thought to be due to more efficient purging of oxygen from the process gas at higher flow rates.
Although preferred embodiments of the invention have been described herein in detail, it will be understood by those skilled in the art that variations may be made thereto without departing from the spirit of the invention or the scope of the appended claims. | An improved fine grained zinc sulfide phosphor is provided for use in ac electroluminescent displays. The fine-grained zinc sulfide phosphor film exhibits improved luminance and may be used in conjunction with a structure or substance to minimize or prevent reaction of the fine grained phosphor with oxygen. The invention is particularly applicable to zinc sulfide phosphors used in electroluminescent displays that employ thick dielectric layers subject to high processing temperatures to form and activate the phosphor films. | 55,641 |
CROSS-REFERENCES TO RELATED APPLICATIONS
This application is a Continuation Application of and claims priority to U.S. Pat. application No. 11/385,278, filed on Mar. 20, 2006, titled “IMAGE PROCESSING SYSTEM FOR SKIN DETECTION AND LOCALIZATION,” by Dempski, et al.
BACKGROUND OF THE INVENTION
1. Technical Field
The invention relates to image processing. In particular, the invention relates to skin detection and localization in an image.
2. Related Art
Continuous and rapid developments in imaging technology have produced correspondingly greater demands on image processing systems. Extensive improvements in imaging technology have given rise to larger and higher resolution image data sets, which in turn require faster and more efficient processing systems to maintain an acceptable level of system responsiveness. At the same time, an increasing number of industries, ranging from security to medicine to manufacturing, have turned to image processing to keep pace with the demands of modern marketplaces.
For example, image processing to detect skin is an important first step in many security industry applications, including facial recognition and motion tracking. In the case of facial recognition, before a security application can compare a face to the faces in a database, an image processing system must first determine whether or not a video or static image even contains skin. If the image does contain skin, the image processing system must determine where in that image the skin is located and whether it is facial skin. Furthermore, it is often desirable to perform such skin and face detection in real-time to analyze, for example, a video stream running at 30 frames-per-second from a security camera.
In the past, a general purpose central processing unit (CPU) in an image processing system performed skin detection. Alternatively, costly and highly customized image processing hardware was sometimes designed and built to specifically detect skin in images. However, annual incremental advancements in general purpose CPU architectures do not directly correlate with an increased ability to perform specialized image processing functions such as skin detection and localization. Furthermore, the resources which a CPU may devote to skin detection are limited because the CPU must also execute other demanding general purpose system applications (e.g., word processors, spreadsheets, and computer aided design programs).
Therefore, past implementations of skin detection and localization were limited to two relatively unsatisfactory options: reduced speed and efficiency of processing performed by a general purpose CPU, or the increased costs and complexity of highly customized hardware. For example, designing and manufacturing highly customized hardware for skin detection to accommodate the massive rollout of security cameras throughout major cities, or the increased security screening at airports, would prove extremely costly and impractical. Yet these and other applications are limited in effectiveness without high performance image processing solutions.
Therefore, a need exists for an improved processing system for skin detection and localization.
SUMMARY
An image processing system provides extremely fast skin detection and localization. The image processing system implements specialized processing techniques in a graphics processing unit (GPU) to perform the majority of the skin detection and localization processing. The main system processor is then free to perform other important tasks. The GPU speeds the detection and localization due to its highly optimized texture processing architecture. The image processing system thereby leads to a less expensive skin detection and localization solution, particularly compared to past systems which relied on highly customized image processing hardware.
The image processing system includes a system processor, a GPU, a system memory, and a skin detection program. The GPU includes a highly optimized graphics processing architecture including a texture memory and multiple pixel shaders. The system memory initially stores a probability table and the source image in which to detect skin. The skin detection program uploads the probability table and the source image from the system memory to the texture memory in the GPU. The skin detection program then defines a render target with respect to the source image and issues a draw call to the GPU. The draw call initiates texture mapping by the pixel shaders of the source image and the probability table onto the render target. The texture mapping operation, in conjunction with a skin threshold (e.g., an alpha test threshold), determines which of the pixels rendered in the render target are considered skin pixels.
In addition to determining whether skin exists in the source image, the image processing system may also locate the skin. To that end, the image processing system includes a skin location program. In one implementation, the skin location program performs a block tree search (e.g., a quad tree search) of the source image. As will be explained in more detail below, in performing the block tree search, the skin location program iteratively issues draw calls to the GPU to cause the pixel shaders to texture map the probability table onto progressively smaller render targets positioned within the source image. The skin location program stores the locations in the source image where skin pixels were found in the system memory.
Other systems, methods, features and advantages of the invention will be, or will become, apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the following claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention can be better understood with reference to the following drawings and description. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. Moreover, in the figures, like referenced numerals designate corresponding parts throughout the different views.
FIG. 1 shows an image processing system which detects and localizes skin in a source image.
FIG. 2 shows an RGB color space including a plot of RGB color values for a set of skin samples.
FIG. 3 shows a Y-Cb-Cr color space including a plot of Y-Cb-Cr color values for a set of skin samples, and a two-dimensional Cb-Cr color space including a plot of the skin samples with respect to only the Cb-Cr values.
FIG. 4 shows a probability plot obtained from the Cb-Cr color space shown in FIG. 3 .
FIG. 5 shows the acts which a setup program may take to setup a GPU for skin detection or localization.
FIG. 6 shows the acts which a skin detection program may take to determine whether skin exists in a source image.
FIG. 7 shows the acts which a skin location program may take to locate skin within a source image.
FIG. 8 shows the acts which a pixel shader control program may take in a GPU for skin detection and localization to identify skin pixels in a source image.
FIG. 9 shows a portion of a source image including skin pixels, and progressively smaller render targets.
FIG. 10 shows a portion of a source image including skin pixels, and progressively smaller render targets.
FIG. 11 shows a skin localization performance graph of an image processing system, in comparison to performing localization entirely on a general purpose CPU.
FIG. 12 shows a skin localization performance graph of an image processing system that saves the render target, in comparison to the performance of a general CPU.
FIG. 13 shows a skin localization performance graph of an image processing system 100 under the assumption that the image processing system does not save the render target, in comparison to the performance of a general purpose CPU.
FIG. 14 shows an image processing system including a communication interface connected to a network.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The elements illustrated in the Figures function as explained in more detail below. Before setting forth the detailed explanation, however, it is noted that all of the discussion below, regardless of the particular implementation being described, is exemplary in nature, rather than limiting. For example, although selected aspects, features, or components of the implementations are depicted as being stored in memories, all or part of the systems and methods consistent with the image processing system may be stored on, distributed across, or read from other machine-readable media, for example, secondary storage devices such as hard disks, floppy disks, and CD-ROMs; a signal received from a network; or other forms of ROM or RAM either currently known or later developed.
Furthermore, although specific components of the image processing system will be described, methods, systems, and articles of manufacture consistent with the systems may include additional or different components. For example, a system processor may be implemented as a microprocessor, microcontroller, application specific integrated circuit (ASIC), discrete logic, or a combination of other type of circuits or logic. Similarly, memories may be DRAM, SRAM, Flash or any other type of memory. Parameters (e.g., thresholds), databases, tables, and other data structures may be separately stored and managed, may be incorporated into a single memory or database, or may be logically and physically organized in many different ways. Programs may be parts of a single program, separate programs, or distributed across several memories and processors.
FIG. 1 shows an image processing system 100 which provides faster than real-time skin detection and localization. The image processing system 100 includes a system processor 102 , a system memory 104 , and a GPU 106 . The GPU may be a graphics processor available from NVIDIA of Santa Clara, Calif. or ATI Research, Inc of Marlborough, Mass., as examples. As will be described in more detail below, the system processor 102 executes a setup program 108 , a skin detection program 110 , and a skin location program 112 from the system memory 104 . The system memory 104 stores a probability table 114 , a source image 116 , and an occlusion query 118 . The system memory 104 also stores a skin detection flag 120 , system parameters 122 , an occlusion result 124 , and skin locations 126 . The system parameters 122 may include a render target upper size limit 128 , a render target lower size limit 130 , and a skin threshold 132 . The memory also stores an occlusion result 124 obtained from the GPU 106 . The occlusion result 124 may provide a skin pixel count 134 .
The GPU 106 includes a texture memory 136 , multiple parallel pixel shaders 138 , and a frame buffer 140 . The texture memory 136 stores a probability texture 142 and an image texture 144 . Multiple parallel pixel shaders 138 process the probability texture 142 and image texture 144 in response to draw calls from the system processor 102 . The multiple parallel pixel shaders 138 execute a pixel shader control program 148 . Alpha test circuitry 150 filters the pixels processed by the pixel shaders 138 . In particular, the alpha test circuitry 150 applies an alpha test 154 to determine whether to keep or discard texture processed pixels. The system processor 102 may establish the skin threshold 132 or other filter parameter for the alpha test 154 . The skin threshold 132 represents a probability below which texture processed pixels are not likely enough to be skin to count as skin pixels. The GPU 106 discards such pixels, but stores the pixels which pass the alpha test 154 as processed pixels 152 in the frame buffer 140 .
The source image 116 may be obtained from a video stream, a digital camera, or other source. The source image 116 includes image data represented in a particular color space, such as the RGB color space. The image processing system 100 , however, may process images with image data represented in other color spaces. The image processing system 100 obtains and stores the source image 116 in the system memory 104 for processing.
The system processor 102 executes the setup program 108 as a precursor to executing the skin detection program 110 and/or the skin location program 112 . The programs 112 and 114 employ the probability table 114 and source image 116 in conjunction with the GPU 106 to rapidly detect and/or locate skin in the source image 116 . The setup program 108 provides the probability table 114 and the source image 116 to the GPU 106 in preparation for texture mapping operations.
The image processing system 100 stores a probability table 114 constructed based on an analysis of images containing skin. The probability table 114 stores the probability that, for any particular pixel expressed in the color coordinate index (e.g., Cb-Cr) of the probability table 114 , the pixel is a skin pixel. Each possible value of Cb and Cr defines a color location in the probability table 114 at which a skin probability is stored. The probability table 114 may be pre-established in the system 100 , or the image processing system 100 may obtain the probability table 114 from an external source, such as the sources described and shown with reference to FIG. 14 . The system processor 102 may dynamically change the probability table 114 during processing to adapt the skin detection and location to any particular probability criteria.
FIG. 2 shows a plot 200 of RGB color values for a set of known skin samples 202 along a Red axis 204 , a Green axis 206 , and a Blue axis 208 . The RGB plot 202 exhibits a significant smear of the skin samples throughout the RGB color space. The variance along each axis 204 , 206 , and 208 makes distinguishing between skin and non-skin pixels difficult in the RGB color space. When the RGB color values are expressed or converted to the Y-Cb-Cr color space, however, the skin pixels localize, pointing to a clearer differentiation between skin and non-skin pixels.
FIG. 3 shows a plot 300 of Y-Cb-Cr color values for the set of skin samples 202 , and a two-dimensional plot 302 of the skin samples 202 with respect to only the Cb-Cr values. The Y-Cb-Cr plot 300 demonstrates tight clustering of the skin samples 202 along the Cb and Cr axes 304 and 306 . The Y axis 308 , which represents luminance, exhibits the largest amount of variance within the Y-Cb-Cr plot 300 of the skin samples. Variation in the luminance value is largely imperceptible to the human eye. Dropping the luminance value results in the two dimensional Cb-Cr plot 302 of the skin samples 202 . The skin samples 202 tend to cluster together with a small amount of variance in the Cb-Cr color space.
FIG. 4 shows a probability table 400 obtained from the two dimensional Cb-Cr color space 302 shown in FIG. 3 . The probability table 400 is setup along a color coordinate index formed from the Cb and Cr (X and Z) axes 402 and 404 . Each index location defines a possible color in the Cb-Cr color space. The probability table 400 establishes a skin probability (e.g., the skin probability 408 ) along the Y axis 406 at each color location.
The probability table 400 may be constructed by binning the Cb-Cr color values of the skin sample set 202 into a 255×255 table, represented by the X and Z axes 402 and 404 . The skin probability represented by the Y axis may be determined by dividing each binned value by the total number of skin samples. The clustered nature of the skin samples 202 in the Cb-Cr color model results in the relatively large skin probability 408 shown in the probability table 400 .
Returning to FIG. 1 , the setup program 108 uploads the probability table 114 and source image 116 to the GPU 106 . The GPU 106 stores the probability table 114 as the probability texture 142 and stores the source image 116 as the image texture 144 in the texture memory 136 . The setup program 108 may also determine the alpha parameters (e.g., the skin threshold 132 ) for the alpha test circuitry 150 and upload the parameters to the alpha test circuitry 150 in the GPU 106 . The alpha test circuitry 150 compares the skin threshold 132 against texture determinations made by the pixel shaders 138 to determine whether the textured pixels should be considered skin pixels. The acts performed by the setup program 108 are shown in FIG. 5 and are described in more detail below.
The skin detection program 110 detects whether or not the source image 116 contains skin. The skin detection program 110 issues draw calls to initiate texture mapping in the multiple parallel pixel shaders 138 . The skin detection program 110 also issues an occlusion query 118 to the GPU 106 to determine the skin pixel count 134 . The skin pixel count 134 is the number of pixels which pass the alpha test 154 and are considered skin pixels. These pixels may also be written to the frame buffer 140 . The skin detection program 110 sets or clears the skin detection flag 120 depending on whether or not the occlusion result 124 returns a non-zero skin pixel count 134 . Accordingly, the skin detection program 110 may act as a fast filter to determine whether skin exists at all in the source image 116 . The acts taken by the skin detection program 110 are shown in FIG. 6 and are described in more detail below.
The skin location program 112 locates skin in the source image 116 . In one implementation, the skin location program 112 executes a block tree search of the source image 116 to locate skin pixels. The skin location program 112 initially searches regions of the source image 116 defined by the render target upper size limit 128 . In a region where skin pixels are detected, the skin location program 112 subdivides that region and searches for pixels within those subregions. The skin location program 112 may continue subdividing and searching until the size of the subregions equals the render target lower size limit 130 .
In this manner, the skin location program 112 efficiently and accurately locates skin within the source image 116 , at a resolution corresponding to the lower size limit of the render target. The skin location program 112 stores the skin locations 126 (e.g., the locations of render targets which have a non-zero skin pixel count) in the system memory 104 . The acts performed by the skin location program 112 are shown in FIG. 7 and are described in more detail below.
The skin detection program 110 and skin location program 112 include instructions that issue draw calls to the GPU 106 to initiate texture mapping in the multiple parallel pixel shaders 138 . The multiple parallel pixel shaders 138 texture map the probability texture 142 and the image texture 144 onto a render target. The render target may be defined by vertices which bound the render target (e.g., upper left and lower right vertices).
The programs 110 and 112 receive the occlusion result 124 arising from texture mapping the render target. The occlusion result 124 specifies the number of skin pixels which pass the alpha test applied by the alpha test circuitry 150 . The programs 110 and 112 may save the locations where skin is found (e.g., by saving the render target locations with respect to the source image 116 ). After executing the skin detection and/or location programs 112 and 114 , the image processing system 100 may report the skin pixel count 134 or skin locations 126 to other applications or may use the skin pixel count 134 or skin locations 126 for other purposes.
FIG. 5 shows the acts 500 which the setup program 108 may take to setup the GPU 106 for skin detection or localization. The setup program 108 obtains the probability table 114 from the system memory 104 (Act 502 ). The setup program 108 then uploads the probability table 114 to the GPU texture memory 136 as the probability texture 142 (Act 504 ). The setup program 108 also obtains the source image 116 from the system memory 104 (Act 506 ), and uploads the source image 116 to the GPU texture memory 136 as the image texture 144 (Act 508 ). The image processing system 100 may thereby apply the speed and parallel processing capabilities of the multiple parallel pixels shaders in the GPU 106 to detect and locate skin in the source image 116 .
The setup program 108 may also determine alpha parameters (Act 510 ). The alpha parameters may include the skin threshold 132 or other criteria used for the alpha test 154 in the alpha test circuitry 150 . The alpha test circuitry 150 determines whether or not a texture processed pixel qualifies as a skin pixel. As described in more detail below in reference to FIG. 14 , the setup program 108 may also determine the alpha parameter based upon values provided external systems, such as systems requesting skin detection or location in the source image 116 by the image processing system 100 . The setup program 108 establishes the alpha test 154 in the GPU 106 (Act 512 ) prior to skin detection or localization.
FIG. 6 shows the acts 600 which the skin detection program 110 may take to determine whether skin exists in the source image 116 . The skin detection program 110 initiates execution of the setup program 108 (Act 602 ). As described above, the setup program 108 uploads the probability table 114 and the source image 116 to the texture memory 136 as the probability texture 142 and image texture 144 respectively.
The skin detection program 110 issues the occlusion query 118 to the GPU 106 to request a skin pixel count 134 (Act 604 ). The occlusion query 118 returns the number of pixels that pass the alpha test 154 for any given render target. The skin detection program 110 also defines the initial render target (Act 606 ). To that end, the skin detection program 110 determines the size and location of the render target with respect to the source image 116 . The initial render target may be a rectangle which has the upper size limit 128 (e.g., the entire size of the source image 116 ) or may be as small as the lower size limit 130 (e.g., a single pixel).
The skin detection program 110 clears the skin detection flag 120 (Act 608 ) and initiates texture mapping of the probability texture 142 and image texture 144 onto the current render target (Act 610 ). To do so, the skin detection program 110 issues a draw call to the GPU 106 to initiate texture mapping by the multiple parallel pixel shaders 138 under control of the pixel shader control program 148 . The GPU 106 determines the transparency of each pixel in the render target, performs the alpha test 154 , and returns the occlusion result 124 , including the skin pixel count 134 . The skin detection program 110 receives an occlusion result 124 which contains the skin pixel count 134 of the current render target. (Act 612 ).
If the skin pixel count is non-zero, the skin detection program 110 sets the skin detection flag 120 (Act 614 ) and may save the render target location at which skin was located (Act 616 ). In other implementations, the skin detection flag 120 may be set when a threshold number of skin pixels are located (e.g., 5% or more of the image contains skin). If the skin detection program 110 will search for skin in other parts of the image, the skin detection program 110 defines a new render target (e.g., a larger render target, smaller render target, or a new location for the render target) (Act 618 ) and initiates texture mapping on the current render target (Act 610 ).
FIG. 7 shows the acts which the skin location program 112 may take to locate skin within the source image 116 . Although the example below assumes the skin location program 112 locates skin throughout the source image 116 , it is noted that the skin location program 112 may instead selectively locate skin in one or more sub-portions of the source image 116 . The skin location program 112 initiates execution of the setup program 108 (Act 702 ). As described above, the setup program 108 uploads the probability table 114 and the source image 116 to the texture memory 136 as the probability texture 142 and image texture 144 respectively. The setup program 108 may also determine the alpha parameters and establish the alpha test 154 in the GPU 106 .
The skin location program 112 defines the render target upper size limit 128 (Act 704 ). The skin location program 112 may define the render target upper size limit 128 as the size of the entire source image 116 , or as any subregion of the source image 116 . The skin location program 112 also defines the render target lower size limit 130 (Act 706 ). The render target lower size limit 130 determines a lower bound on the size of the render target (e.g., 64×64 pixels, 16×16 pixels, 1×1 pixel, or any other lower bound). As the render target decreases in size, the location accuracy increases.
The skin location program 112 issues the occlusion query 118 to the GPU 106 (Act 708 ). The skin location program 112 sets an initial render target (Act 710 ). For example, the skin location program 112 may set the initial render target to the render target upper size limit 128 , and select a position (e.g., the upper left hand corner of the source image) for the render target.
The skin location program 112 makes a draw call to the GPU 106 to initiate texture mapping of the probability texture 142 and image texture 144 onto the current render target (Act 712 ). Alpha testing in the GPU acts as a filter on the transparency values of the texture mapped pixels to determine the number of texture mapped pixels which qualify as skin pixels. The skin pixel count 134 is returned in the occlusion result 124 .
When the render target is full or skin pixels or empty of skin pixels, the skin location program 112 does not subdivide the render target. When the render target is full of skin pixels, the skin location program 112 saves the render target locations as skin locations 126 (Act 718 ). The skin location program 112 may also save the contents of the render target in the memory 104 . If more of the source image remains to be processed, the skin location program 112 sets a new render target (Act 720 ) (e.g., moves the render target to a new location with respect to the source image) and again initiates texture mapping.
If the render target was partially full of skin pixels, the skin location program 112 determines whether the render target has reached the lower size limit 130 . If so, the skin location program 112 saves the skin locations (Act 718 ) and determines whether more of the source image remains to be processed. Otherwise, the skin location program subdivides the render target (Act 722 ). For example, when applying a quad-tree search strategy, the skin location program 112 may sub-divide the render into four smaller render targets. A new, smaller, render target is therefore set (Act 720 ), and the skin location program 112 again initiates texture mapping.
In the example above, the skin location program 112 did not subdivide a render target which was completely empty of skin pixels or full of skin pixels. In other implementations, the skin location program 112 may also be configured to process a partially filled render target as if it contained either zero skin pixels, or all skin pixels. For example, the skin location program 112 may process a render target containing between zero and a threshold number of skin pixels as if the render target contained zero skin pixels. Likewise, the skin location program 112 may process a render target containing between a given threshold of skin pixels and all skin pixels as if the render target were full of skin pixels.
The skin location program 112 described above may also execute skin location using predicated draw calls. A predicated draw call used in the skin location program 112 is a draw call which instructs the GPU to draw a particular render target, and if skin is detected in that render target, to subdivide the render target into subregions and draw those subregions. Accordingly, the skin location program 112 issues one draw call to draw the render target and the four smaller render targets as opposed to issuing up to five draw calls to draw the same regions.
FIG. 8 shows the acts which the pixel shader control program 148 may take in the GPU 106 for skin detection and localization to identify skin pixels in the source image 116 . The pixel shader control program 148 obtains a pixel from the image texture 144 (Act 802 ). The pixel shader control program 148 converts the pixel from the color space in which the image texture 144 exists, such as the RGB color space, to the color space in which the probability texture 142 exists, such as the Cb-Cr color space (Act 804 ). The converted pixel becomes a probability coordinate which the pixel shader control program 148 indexes into the probability texture 142 .
The pixel shader control program 148 determines the skin probability for the pixel by indexing the probability coordinate into the probability texture 142 (Act 806 ). The indexed value resulting from the texture mapping described above may be an RGBA value, where A contains the probability that the pixel's Cb-Cr value is skin. The pixel shader control program 148 sets the alpha value of the output pixel to the skin probability obtained from the probability texture (Act 808 ). In this instance the RGB values may contain other data such as the type of skin the pixel contains. The resulting indexed value may also be a one value component texture containing the probability that the pixel contains skin. In these examples, the pixel shader control program 148 sets the A value as the transparency of the indexed pixel. The pixel shader control program 148 , however, may output any other component on any other axis of the probability texture 142 as the rendered pixel output value (e.g., the transparency value) for the pixel.
The pixel shader control program 148 then outputs the texture mapped pixel 152 (Act 810 ), which is then subject to the alpha test to determine whether the pixel qualifies as a skin pixel. Table 1, below, shows one example of a pixel shader control program which converts RBG to Cb-Cr and in which ‘MainTexture’ refers to the image texture 144 , ‘dot’ is a dot product operation, and ‘tex2D’ refers to the probability texture 142 .
TABLE 1
struct VS_OUTPUT
{
float4 Position : POSITION;
float4 Color : COLOR;
float2 TexCoords0 : TEXCOORD0;
float2 TexCoords1 : TEXCOORD1;
};
struct PS_OUTPUT
{
float4 Color : COLOR;
};
sampler MainTexture : register(s0);
sampler CbCrBinTexture : register(s1);
PS_OUTPUT main(const VS_OUTPUT OutVertex)
{
PS_OUTPUT OutPixel;
float2 cbcrcolors;
float2 cbcrwithrange;
float4 CbConverter = {−0.168736, −0.331264, 0.500, 0.00};
float4 CrConverter = {0.500, −0.418688, −0.081312, 0.00};
cbcrcolors.x = dot(CbConverter, tex2D(MainTexture,
OutVertex.TexCoords0));
cbcrcolors.y = dot(CrConverter, tex2D(MainTexture,
OutVertex.TexCoords0));
cbcrwithrange.y = cbcrcolors.x * 0.8784 + 0.5020;
cbcrwithrange.x = cbcrcolors.y * 0.8784 + 0.5020;
float4 retcolor = tex2D(CbCrBinTexture, cbcrwithrange);
OutPixel.Color = retcolor.r;
return OutPixel;
}
Table 2 shows another example of a pixel shader control program 148 in which the textured pixel is determined using a 3D direction vector to index into six 2D textures arranged into a cube map. The cube map texture construct is a set of six textures, each representing the side of a three-dimensional cube. The pixel shader control program may use any three component RGB value as a vector to point from the center of the cube to a spot on the cube wall.
TABLE 2
struct VS_OUTPUT
{
float4 Position : POSITION;
float4 Color : COLOR;
float2 TexCoords0 : TEXCOORD0;
float2 TexCoords1 : TEXCOORD1;
};
struct PS_OUTPUT
{
float4 Color : COLOR;
};
sampler MainTexture : register(s0);
sampler CbCrBinTexture : register(s1);
PS_OUTPUT main(const VS_OUTPUT OutVertex)
{
PS_OUTPUT OutPixel;
float4 Color1 = tex2D(MainTexture, OutVertex.TexCoords0);
float4 retcolor = texCUBE(CubeMapTexture, Color1);
OutPixel.Color = retcolor.r;
return OutPixel;
}
FIGS. 9 and 10 show examples of a 48×48 pixel portion of a source image 900 including skin pixels 902 , render targets 904 , 906 , 908 , and 910 , and progressively smaller render targets 1000 , 1002 , 1004 , and 1006 . FIGS. 9 and 10 illustrate steps the skin location program 112 may take to locate skin within the source image 900 . In this example, the skin location program 112 sets the render target upper size limit 128 as 48×48, and the render target lower size limit 130 as 12×12. The skin location program 112 sets the 48×48 portion of the source 900 as the initial render target. The skin location program 112 initiates texture mapping of the probability texture 142 and image texture 144 onto the initial render target 900 .
The skin location program 112 determines that the initial render target 900 contains more than zero, but less than all skin pixels 902 . As a result, the skin location program 112 subdivides the initial render target 900 into four smaller 24×24 subregions 904 - 910 . The skin location program 112 sets the upper left subregion 904 as the new render target and initiates texture mapping as to the render target 904 .
The skin location program 112 determines that the render target 904 contains all skin pixels 902 . The skin location program 112 stores the skin locations 126 in system memory 104 . The skin location program 112 sets the upper right subregion 906 as the new render target because the skin location program 112 has not yet processed the entire subdivided render target 900 . The skin location program 112 initiates texture mapping on the render target 906 and determines that it contains zero skin pixels 902 . The skin location program 112 moves to the lower left subregion 908 as the new render target and determines that the render target 908 also contains zero skin pixels 902 .
The skin location program 112 then moves to the lower right subregion 910 as the new render target and, after initiating texture mapping on to the render target 910 , determines that the render target 910 contains more than zero, but less than all skin pixels 902 . The render target 910 , 24×24 pixels, has not reached the render target lower size limit 130 . Accordingly, the skin detection program 110 subdivides the render target 910 (in this example, into four quadrants).
FIG. 10 shows the render target 910 subdivided into progressively smaller 12×12 subregions 1000 - 1006 . The skin location program 112 sets one of the progressively smaller subregions 1000 - 1006 as the new render target. In this example, the skin location program 112 sets progressively smaller subregion 1000 as the new render target.
After determining that the render target 1000 contains zero skin pixels 902 , and that less than the entire previously subdivided render target 910 has been processed, the skin location program 112 sets the progressively smaller subregion 1002 as the new render target. The skin location program 112 determines that the render target 1002 contains all skin pixels 902 and stores the skin location to system memory 104 . The skin location program 112 sets progressively smaller subregion 1004 as the new render target. The skin location program 112 determines that the render target 1004 contains more than zero, but less than all skin pixels 902 . The skin location program 112 also determines that the render target 1004 size equals the render target lower size limit 130 .
The skin location program 112 stores the skin location into the system memory 104 . Because less than the entire previously subdivided render target 910 has been processed, the skin location program 112 sets the progressively smaller subregion 1006 as the new render target. The skin location program 112 determines that the render target 1006 contains more than zero but less than all skin pixels 902 . The skin location program 112 stores the render target 1006 to system memory 104 instead of subdividing further because the size of the render target 1006 equals the render target lower size limit 130 . Thus, the skin location program 112 determines locations for the skin pixels 902 present in the portion of the source image 900 .
FIG. 11 shows a skin localization performance graph 1100 of the image processing system 100 in comparison to performing localization entirely on a general purpose CPU. The performance graph 1100 shows performance plots 1102 - 1112 achieved using modern GPUs 106 . The performance plots 1102 , 1106 , and 1110 show system 100 performance using different GPUs where render targets are not saved. The performance plots 1106 , 1108 , and 1112 show system performance using different GPUs where render targets are save to memory 104 . As demonstrated in FIG. 11 , using the image processing system 100 to locate skin results in significantly improved performance (in some cases several hundred times faster) compared to the performance plot 1114 of skin location done on a general purpose CPU.
FIG. 12 shows a skin localization performance graph 1200 of the image processing system 100 that saves the render target in comparison to the performance of a general CPU. The performance graph 1200 shows different performance plots 1202 - 1214 for the image processing system 100 when the image processing system 100 saves render targets of the following render target block levels: 8×8 blocks, plot 1202 , 16×16 blocks, plot 1204 , 32×32 blocks, plot 1206 , 64×64 blocks, plot 1208 , and 128×128 blocks, plot 1210 . The performance graph 1200 also shows the performance 1212 and the average performance 1214 of the image processing system 100 where the image processing system 100 uses the quad tree approach to locating skin. As demonstrated by the performance graph 1200 , the image processing system 100 , even when saving 8×8 blocks, performs far faster (in some cases, hundreds of times faster) than processing on a general purpose CPU.
FIG. 13 shows a skin localization performance graph 1300 of the image processing system 100 under the assumption that the image processing system 100 does not save the render target, in comparison to the performance of a general purpose CPU. The performance of the following render target block levels are charted: 8×8 blocks, plot 1302 ; 16×16 blocks, plot 1304 ; 32×32 blocks, plot 1306 ; 64×64 blocks, plot 1308 ; and 128×128 blocks, plot 1310 . The performance graph 1300 also shows the performance 1312 and the average performance 1314 of the image processing system 100 where the image processing system 100 uses the quad tree approach to locating skin. As demonstrated by the performance graph 1300 , the image processing system 100 is far faster (typically many hundreds of times faster) than processing on a general purpose CPU.
The different performance plots in FIGS. 12 and 13 illustrate that there is overhead associated not only with saving the render targets, but also with issuing draw calls to the GPU. For example, FIG. 13 (which assumes that render targets are not saved) shows that issuing draw calls for 128×128 blocks over the render target yields higher performance than executing a significant number of additional draw calls for covering the render target using 8×8 blocks. Nevertheless, the performance is still greater than that of a general purpose CPU, and includes the added benefit of very high accuracy at a block size of 8×8, without saving the render target during the initial pass. The quad tree approach yields an intermediate level of performance (which is still far greater than that of a general purpose CPU) because that approach need not further subdivide blocks which are full or empty of pixels. The quad tree approach there need not drill down to the smallest block size in many instances.
FIG. 14 shows the image processing system 100 , including a communication interface 1400 connected to a network 1402 . The image processing system 100 communicates over the network 1402 with service requestors 1404 which, for example, submit source images, probability tables, and feature detection and/or location requests to the image processing system 100 . The feature detection requests may be skin detection requests, or requests to detect other characteristics in the source image, such as hazardous substances. To that end, the service requestors may provide probability tables which establish probabilities for detecting the feature of interest (e.g., a probability table which assigns probabilities to certain colors being a hazardous substance). The service requestors 1404 may be, as examples, external security, surveillance, medicine, and/or other systems which request skin detection and/or localization in the source image 116 . Alternatively or additionally, the image processing system 100 may obtain source images from the image sources 1406 . The image sources 158 may include a video feed, digital camera, or other image source.
The service requestors 1404 may also provide other data to the image processing system 100 . For example, each service requestor 1404 may provide a different feature detection threshold (e.g., a skin threshold 132 ) for use in a specific application. The service requestors 1404 may also specify the render target upper size limit 128 , the render target lower size limit 130 , or other parameters. For example, where the service requestor 1404 requests highly accurate skin location in the source image 116 , the image processing system 100 may set a relatively small (e.g., 8×8, 4×4, 2×2, or 1×1) render target lower size limit 130 . When the service requestor 1404 specifies less stringent accuracy requirements, the image processing system 100 may set a larger render target lower size limit 130 .
The service requestors 1404 may use the skin detection and/or location data for a variety of applications. For example, the image processing system 100 may detect and locate skin in a source image 116 as a pre-processing step for a facial recognition system. In addition to skin detection and localization, the image processing system 100 described above may be used for other image processing tasks. For example, the image processing system 100 may be configured to detect and/or locate organic compounds for use at a security station in an airport, bus terminal, government office building, or other facility. In this example, the probability table 114 may be constructed based upon an image set of organic compound samples.
In another example, the image processing system 100 may be configured to detect and/or locate certain terrain, objects, or other details in satellite images. For example, using a probability table 114 based upon a set of marijuana field image samples, the image processing system 100 may detect and locate other marijuana fields in satellite or high altitude images. As another example, the image processing system 100 may be configured to detect specific tissues or other materials in medical images.
While various embodiments of the invention have been described, it will be apparent to those of ordinary skill in the art that many more embodiments and implementations are possible within the scope of the invention. As one example, the render target may stay the same size during skin detection or localization (e.g., a 640×480 canvas onto which the GPU performs texture mapping), while the draw calls may specify smaller blocks within the render target. In other words, in other implementations, the render target itself need not be subdivided. Instead, the draw calls may specify portions of the render target for skin detection and localization texture processing. Accordingly, the invention is not to be restricted except in light of the attached claims and their equivalents. | An image processing system provides faster than real-time skin detection and localization. The system uses the highly optimized architecture of a graphics processing unit to quickly and efficiently detect and locate skin in an image. By performing skin detection and localization on the graphics processing unit, the image processing system frees the main system processor to perform other important tasks, including running general purpose applications. The speed with which the image processing system detects and localizes skin also facilitates subsequent processing steps such as face detection and motion tracking. | 50,857 |
BACKGROUND OF THE INVENTION
The invention relates to a vehicle for beach cleaning comprising a vehicle frame, at least one wheel axis disposed on it, a vertically adjustable garbage pickup, a conveyor adjoining the garbage pickup and conveying the garbage taken over from the garbage pickup to a collecting receptacle, disposed at the rear end of the vehicle frame and a supply rotor allocated to the pickup area of the garbage pickup.
Such a beach cleaning vehicle is known from U.S. Pat. No. 4,482,019. Refuse is picked up from the ground, e.g. a sandy beach, by a supply rotor designed with tines and conveyed to a conveyor belt. The tines of the supply rotor are bent in the direction of motion at their ends, the rotor rotates in the same direction.
It is disadvantageous that the pollutants have to be picked up from the ground in the direction of motion and must be guided past the supply rotor over a range of 180°. Impurities flung away forwardly by the tines partly bounce against a rotor housing and partly fall back onto the beach; due to this they come in front of the supply rotor again and must be picked up again.
The rotational speed of the rotor is added to the driving speed in the pickup area so that the refuse is tangentially flung forwardly in the direction of motion upon contact with the tines. In this fashion, pollutants can accumulate increasingly in front of the supply rotor and impair a further use.
The tines are greatly loaded when striking against the pollutants or the sand due to the high relative speed, and they may break.
Fibrous pollutants such as algae can wind themselves around the supply rotor and the tines due to the rotation of the supply rotor and the long entrainment up to the delivery to the transport belt and are matted together with it. In the case of greater algae pollution the known supply rotor must be cleaned frequently and freed from the algae.
Due to the design of the supply rotor and its allocation to the transport belt, pollutants are only picked up from the beach, which are seized by the rotor. Pollutants not picked up by the supply rotor cannot be picked up by the transport belt and remain on the beach.
The entire vehicle frame with all means attached thereto is lowered for the vertical adjustment of the supply rotor. The wheels mounted on a strap-shaped mounting are pivoted rearwardly by an actuating means, and due to this the entire vehicle is lowered. A vertical adjustment of the supply rotor relative to the transport belt is not possible. The distance between supply rotor and transport belt can likewise not be varied. Bulky pollutants cannot be picked up, and lead possibly to a damage to the vehicle.
A separation of pollutants and sand only takes place in the known beach vehicle by means of a sieve belt connected downstream of the transport belt. It must transport both the pollutants and the sand. This can in particular greatly load the vehicle in terms of weight, in particular if the sand is moist. Part of the sand with the pollutants is moreover further transported up to the collecting receptacle. The collecting receptacle is filled prematurely and must be exchanged for another receptacle or be emptied.
SUMMARY OF THE INVENTION
The invention is based on the object of providing a vehicle for beach cleaning of the type mentioned at the beginning which is improved as regards the supply, pickup and transport of refuse and the separation of the refuse and sand and the disposal of the pollutants.
This object is attained in a vehicle for beach cleaning having the features of the preamble of claim 1 by the fact that a swivel frame supporting the garbage pickup and the supply rotor is mounted in lowerable fashion on the vehicle frame for the vertical adjustment, the supply rotor is pivotably mounted on it by means of links across a swivelling range and is in particular rotatable counter-clockwise about an axis of rotation mounted on the links.
The supply rotor is disposed in a first, front operating position for the supply of garbage and/or sand to the garbage pickup in the direction of motion in front of the pickup V-ledge disposed in front of the garbage pickup, the distance between the V-ledge and the axis of rotation of the rotor is minimal in a second, central operating position, and the rotor is disposed at a distance to the V-ledge or the garbage pickup which is greater as compared with the second operating position in a third, rear operating position.
Consequently not the entire vehicle frame must be lowered according to the invention for the vertical adjustment of the garbage pickup, but only the swivel frame. Depending upon the application, the garbage pickup is lowered with the pickup V-ledge to the sand or into the sand. The pollutants and, possibly, sand are picked up via the V-ledge. The supply rotor is also lowered at the same time. Since it is mounted pivotably relative to the garbage pickup, both the distance of the supply rotor to the garbage pickup or the V-ledge and the height of the supply rotor relative to the sand can be varied indepedently of the garbage pickup.
The supply rotor is disposed in the direction of motion in front to the V-ledge, and thus also in front of the garbage pickup in a first operating position. If the V-ledge rests approximately on the sand in this position, the supply rotor rotates above the sand or penetrates only somewhat into the sand surface. The garbage pickup supplies all superficial pollutants to the garbage pickup in this position. Only a very small sand capture takes place, and a high driving speed is consequently possible. Since the rotor rotates moreover counter-clockwise, rotational speed and driving speed are not added, which leads to a lesser load of the rotor. The rotor flings the pollutants in the direction of the V-ledge and the garbage pickup, a partial separation of pollutants as a function of their weight taking place at the same time. More light-weight pollutants are flung over a greater distance in the direction of the garbage pickup than heavier ones, e.g. sand.
Impurities possibly not seized by the supply rotor are subsequently still picked up by the V-ledge and conveyed to the garbage pickup. In this fashion, all pollutants are picked up from the beach up to a certain penetration depth and the beach is thoroughly cleaned.
The first operating position is in particular of advantage in the case of wet sand or in the flood border area, since only little sand pickup takes place and the surface is thoroughly cleaned.
The second operating position of the supply rotor is preferably used for dry sand. In this position the rotor does not only serve for supplying pollutants to the garbage pickup, but also for accelerating the sand and the pollutants picked up by the V-ledge. The V-ledge is partly immersed in the sand. The supply rotor forming a duct with the V-ledge catches partly the sand and in particular the garbage lying on the surface of the sand. In similar fashion as in the first operating position, the rotor flings the materials located in its area of rotation in the direction of the garbage pickup. The lighter parts are flung over a greater distance than the heavier parts. In this fashion, sand and pollutants are already supplied to the garbage pickup in partly separated fashion and can more easily be separated still further on it. At the same time, a higher driving speed is possible due to the accelerated conveying of the picked up materials.
It is in particular possible in the third operating position to also pick up bulky parts. Since the distance between supply rotor and V-ledge or garbage pickup is relatively great, the parts picked up by the V-ledge can be guided to the garbage pickup through the gap formed between rotor and V-ledge. Due to its rotation, the rotor promotes the further transport.
The pollutants largely already separated from the sand by the supply rotor and the garbage pickup are freed from sand possibly entrained almost completely on the subsequent conveyor and supplied to the collecting receptacle.
The features of claims 2 and 3 are furthermore advantageous, since in this fashion the swivel frame is of a simple design and is disposed completely below the vehicle frame. The upper side of the vehicle frame can be additionally used for many purposes, such as for the transporting of building material, earth, gardening articles or the like. The swivel frame itself can be lowered with its end located in the direction of motion due to the mounting on its rear end. Supply rotor and pickup V-ledge are disposed on said end.
The features of claims 4 and 5 are advantageous since a multi-purpose use of the vehicle is possible in this fashion. The swivel frame together with garbage pickup and supply rotor can be exchanged for another swivel frame with corresponding means by means of detachable quick-action closures. A retrofitting of the vehicle to other fields of application is possible without great time expenditure. The flexibility of the vehicle is increased by this. A use for cleaning asphalted roads is e.g. also possible, the pickup V-ledge being preferably designed elastically and the supply rotor being particularly designed as brush roller in this case. The vehicle can also be used without swivel frame for general transport purposes.
The features of claims 6 to 9 are also advantageous, since the garbage pickup can be used for many fields of application in this fashion. The pollutants are taken over from the supply rotor or the V-ledge by the elevator and are conveyed to the conveyor connected downstream. If the elevator has a drive of its own, its speed can be adjusted independently of the rotational speed of the supply rotor or of the speed of the conveyor and can be easily adapted to applications with different garbage volumes.
The design of the vehicle according to claims 10 to 12 is also advantageous. The pickup area of V-ledge, supply rotor and garbage pickup can be designed in accordance with the vehicle width. The width of the flow of garbage is reduced in accordance with the given conditions via the disposed lateral blades and directing plates and can thus be passed through between the wheels attached to the wheel axis. The pollutants are picked up before they are possibly compacted with the wheels of the vehicle or even pressed into the ground, and the sand is cleaned across the entire width of the vehicle. A larger width of e.g. the V-ledge would basically also be possible, however, this would render the handling of the vehicle more difficult and persons might be injured due to the ends of the V-ledge laterally projecting from the contour of the vehicle.
The features of claims 13 and 14 are advantageous inasmuch as e.g. an automatically controlled lowering and lifting of the swivel frame is possible by means of the actuating means. The actuating means may be designed as a hydraulic actuating cylinder and can e.g. be remotely controlled by the driver of the vehicle. In order to be able to use the entire width of the swivel frame for the garbage pickup, the actuating means is disposed laterally on the frame.
It is furthermore advantageous if the angle of incidence for the garbage pickup of the pickup V-ledge relative to the ground is greater than the angle of incidence of the garbage pickup. In this fashion a narrowing transport duct is obtained between pickup V-ledge and supply rotor in the second operating position for the further transport of picked up garbage and sand, the end of the transport duct having a larger aperture angle so that the material picked up due to this can be distributed better across the garbage pickup.
A further development of the vehicle according to claims 16 to 18 is furthermore suitable. Material possibly flung upwardly or potentially beyond the garbage pickup by the rotor is recovered and deflected back into the garbage pickup by means of the baffle lining. At the same time, lumps are e.g. comminuted during the impact, which renders a subsequent separation of garbage and sand easier on the garbage pickup or the conveyor. The height of the baffle lining decreasing in particular oppositely to the direction of motion prevents that garbage or sand is flung away beyond the garbage pickup. The covering of the baffle lining serves additionally as a stop during the swivelling back of the swivel frame in the direction of the vehicle frame and for mounting the swivel axis of the rotor.
Advantageous developments of a supply rotor suspension are revealed by claims 19 to 21. Due to the use of the U-shaped frame, the supply rotor is suspended by means of the frame fundamentally in pendulous fashion. The entire frame can be pivoted about the swivel axis by means of the flange bearing projecting from the U-web and the corresponding bearing straps projecting from the covering.
The rotor is thus suspended easily accessibly. A pivoting across the swivelling range comprising the operating positions is moreover possible in a very simple fashion due to the arrangement of the flange bearings and bearing straps. The swivel radius of the supply rotor is relatively large, but nevertheless it is possible to pivot the swivel frame up to close to the vehicle frame, flange bearings and bearing strips of the rotor being disposed laterally next to the vehicle frame. A vertical fine adjustment of the rotor is moreover possible thanks to the special mounting of the axis of rotation of the rotor.
In order to adjust the supply rotor independently of other means in its rotational speed it is furthermore advantageous if a driving means is allocated to one end of the axis of rotation of the rotor. This may be a hydromotor which is connected to the hydraulic system of the vehicle and can possibly be adjusted by the driver.
The features of claims 23 and 24 are also advantageous, since the rotor can be pivoted independently of the garbage pickup due to the actuating means for pivoting the rotor. The actuating means can e.g. be designed as a hydraulically operable piston. The actuating means is attached with one end near the axis of rotation of the rotor so that no greater leverage occurs. In order to render the pivoting easier, the other end of the actuating means is disposed on a side wall of the baffle lining.
The supply rotor comprises a plurality of radially projecting tines defining the rotor circumference in an advantageous embodiment. The pollutants or the sand are flung in the direction of the V-ledge or the garbage pickup by means of the tines. The tines can be designed as elastic tines of metal or plastic material fixedly disposed on the axis of rotation of the rotor. It is likewise possible to mount the tines in spring-loaded fashion.
In order to achieve a minimum distance between V-ledge and axis of rotation of the rotor in the second operating condition and to optimize the transport effect of the rotor in this position it is advantageous if the pickup V-ledge extends substantially in a direction in parallel to a tangent of a swivel curve in the direction of motion, the swivel curve being defined as envelope of a part of the rotor circumference opposite to the swivel bearing.
Advantageous developments of supply rotor and V-ledge result from the features of claims 27 to 30.
The features of claims 31 and 32 are advantageous inasmuch as an additional separation of the garbage from the entrained ground materials is possible by means of the conveyor. In order to prevent a soiling of or damage to the wheel axis and all lines located below the conveyor means, the installation of a baffle plate above the rear axle is advantageous. A deflection axis can be formed as an unbalanced shaft on the conveyor but also on the garbage pick up and facilitate the shaking off of sand or ground material by a specific vibrating movement vertically to the direction of transport.
It is advantageous for mounting the actuating means of the swivel frame if the front transverse bar of the vehicle frame projects laterally beyond the transverse bars up to about the width of the vehicle and the actuating means are mounted on its ends. At the same time, tipping means for a loading area disposed on the vehicle frame can be mounted on these ends. The vehicle frame is substantially formed by a frame rectangle formed by two longitudinal bars and two transverse bars and a frame triangle disposed on its front edge in one example of embodiment. A coupling means for a traction vehicle is disposed on the tip of the triangle.
In order to obtain a loading area being as large as possible, it is advantageous if the loading area extends almost completely across garbage pickup and conveyor. The collecting receptacle is pivotable across the loading area by means of two supports disposed laterally on the vehicle frame or on the loading area and can be emptied uniformly on the loading area.
The features of claims 35 to 37 are moreover advantageous inasmuch as a uniform dumping of the collecting receptacle across the entire length of the loading area is possible by means of the tipping connecting bars. The first garbage is directly emptied above the rear end of the loading area on the same via a dumping edge of the collecting receptacle, and the collecting receptacle is gradually further pivoted during the pivoting towards the front end of the loading area by means of the arrangement of tipping links and supports. The support of the collecting receptacle can be rotated from a substantially horizontal position into an approximately vertical position by means of a tipping means. Both the tipping means for the collecting receptacle and the tipping means for the loading area can be designed as hydraulically operable pistons.
The further development of the vehicle according to claims 38 to 40 is furthermore suitable. A vertical adjustment of the rear end of the vehicle is possible due to the wheel axis designed as a lift axis. The vehicle frame is lifted by means of the lifting means in particular for emptying the loading area, and the collecting garbage can also be dumped into a higher container.
BRIEF DESCRIPTION OF THE DRAWINGS
The solutions suggested according to the invention and advantageous examples of embodiment thereof are explained and described in the following by means of the Figs. represented in the drawing.
FIG. 1 shows a lateral view of the vehicle for beach cleaning with pivoted loading area and collecting receptacle.
FIG. 2 shows a lateral view of the vehicle for beach cleaning with lowered swivel frame.
FIG. 3 shows a top view of the vehicle.
FIG. 4 shows a top view of garbage pickup and conveyor.
FIG. 5 shows a front view of the supply rotor.
FIG. 6 shows a lateral view of a frame for mounting the supply rotor.
FIG. 7 shows a lateral view of a driving means of the supply rotor.
FIG. 8 shows a lateral view of a first operating position of the supply rotor.
FIG. 9 shows a lateral view of a second operating position of the supply rotor.
FIG. 10 shows a lateral view of a third operating position of the supply rotor.
FIG. 11 shows a front view of a lift axis according to the invention.
FIG. 12 shows a lateral view of the lift axis and
FIG. 13 shows a further lateral view of the lift axis.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The vehicle for beaching cleaning 1 according to the invention is represented in FIG. 1 together with a traction vehicle 2. The beach cleaning vehicle 1 is connected to the traction vehicle 2 by means of a coupling means 3 and a coupling means 77 formed on the traction vehicle 2 and movable across the ground 68. The vehicle 1 is substantially formed of the vehicle frame 4, an upwardly folded loading area 5, a swivel frame 7 disposed below the vehicle frame 4 and a collecting receptacle 6 pivoted across the loading area 5.
The coupling means 3 is disposed on the vehicle frame 4 on its front end, and a substantially horizontal tipping axis 51 for the loading area 5 is disposed on its rear end. The loading area 5 is upwardly tilted about the tipping axis 51 by about 45° with respect to the vehicle frame 4. An adjustable rear wall 50, which is pivotably mounted on the rear upper end of the loading area 5 is partly opened. A collecting receptacle pivoting means 39 is disposed on a side wall 87 of the loading area near the lower side pointing towards the vehicle frame. The same extends substantially in parallel and closely adjacent to the lower side of the side surface 87. The pivoting means 39 is mounted on a front end 40 on the side surface 87, while the rear end 41 is mounted on the tip of a triangular frame element 48, 49. The ends of the legs 48 and 49 of the triangular frame element are connected with the support 42. The support and the legs of the triangle close a substantially equilateral triangle. Near the connection between the legs of the triangle 48 and the support 42, the support 42 is pivotably mounted with its end 43 on the lower side of the lateral wall 87 of the loading area 5. The collecting receptacle 6 is pivotably mounted relative to the support 42 on the opposite end 44. The end 44 of the support 42 is disposed approximately in the surface centroid of a lateral surface of the collecting receptacle 6. A transverse bar 45 extends rectangularly to the support 42 along the collecting receptacle 6.
A tipping link 46 is rotatably mounted adjacent to the end 43 of the support 42 on the side wall 87 of the loading area 5. The bearing point 164 of the tipping link 46 is represented in FIG. 2 or 3 and is located staggeredly in the direction of the upper edge of the lateral wall 87 relative to the bearing point 43 of the support 42. The tipping link 46 is rotatably mounted on the upper end 47 on the collecting receptacle 6. The position of the link mounted 47 on the collecting receptacle is approximately at the intersection of the top surface of the collecting receptacle and a straight line running from the bottom surface of the receptacle to the top surface of the receptacle, which line passes through the mounting location 44 of the receptacle 6 and the support 42. The tipping link 46 is designed with a length being somewhat smaller than that of the support 42.
The loading area 5 is pivoted with respect to the vehicle frame 4 by means of a loading area tipping means 36 which is disposed between a transverse bar 35 of the frame 4 and the lateral surface 87 of the loading area 5. The tipping means 36 is rotatably mounted on the transverse bar 35 with one end 37 and is disposed approximately above the end 43 of the support 42 centrally to the side wall 87 with the other end 38.
An actuating means 32 is rotatable mounted with one end 34 on the transverse bar 35 opposite to the end 37 of the tipping means 36. The actuating means 32 is rotatably mounted with its other end 33 on a swivel frame 7 disposed below the vehicle frame 4. The swivel frame (7) consists essentially of longitudinal bars forming a rectangle and at least one transverse bar. The rear end of the swivel frame is rotatably mounted on the vehicle frame.
The swivel frame 7 can be lowered in the direction towards the ground 68 by means of a substantially horizontal swivel axis 8 disposed near the rear end of the swivel frame by means of the actuating means 32. A number of rollers 20, 21, 24, 25, 26, 27 are rotatably mounted in the swivel frame 7. The rollers 20 and 21 serve as deflecting axes for a conveyor belt formed of an upper run 22 and lower run 23. The rollers 24, 25 and 26 are designed as supporting rollers and define a transport plane of the upper run 22 together with the deflecting axes 20 and 21. The rollers 27 and 28 are in each case disposed between the deflecting axes 20 or 21 and the supporting rollers 24 or 26 adjacent to them. They are downwardly staggered with respect to these rollers and not in contact with the upper run 22. The rollers 27 and 28 serve as tensioning rollers and are disposed below the lower run 23 and guide it in the direction of the upper run 22. The lower run 23 sags in the direction of the ground 68 between the tensioning rollers 27 and 28.
A baffle lining 15, which is a cover for the swivel frame 7 is adjacently disposed downstream of the supply rotor 11. The baffle lining consists of two lateral walls 134 and a covering 16, that extends between and connects the walls 134 at their upper ends. The baffle lining 15 is disposed on the swivel frame 7 above the deflecting axis 20 and the supporting roller 24. The baffle lining 15 points from the swivel frame 7 in the direction of the vehicle frame 4. In the pivoted condition of the swivel arm 7 represented in FIG. 1 a covering 16 of the baffle lining 15 is in abutment with the lower side of the vehicle frame 4 across its entire length. The end 33 of the actuating means 32 is disposed at the rear end of the baffle lining 15 near the swivel frame 7. A directing plate 65 is disposed between the swivel axis 33 and the end 8 of the swivel frame 7 mounted on the vehicle frame 4, which extends in the longitudinal direction of the swivel frame projecting beyond the upper run 22.
An actuating means 29 extends between a rear upper edge of the baffle lining 15 and a supply rotor 11 disposed before it for pivoting the rotor. It is mounted with its rear end 31 on the baffle lining 15 and with its front end 30 on the supply rotor 11.
The supply rotor 11 is rotatable about an axis of rotation. It has a plurality of radially projecting tines 67, wherein the tines may be spring tines. For example, the supply rotor may take the form of a brush roller or other conventional supply rotor. A driving means covering 17 extends between axis of rotation 18 and the vehicle frame 4. It projects partly laterally beyond the vehicle frame 4. A bearing strap 19 is directed towards the upper end of the covering 17. The bearing strap is disposed on a front edge of the covering 16 of the baffle lining 15.
In extension of the swivel frame 7 a lateral blade 64 partly laterally covering the supply rotor 11 is directly disposed below the supply rotor 11. The height of the lateral blade 64 corresponds approximately to the height of the end of the swivel frame 7, which is adjacent to it. While the swivel frame 7 encloses an acute angle with the vehicle frame 4 and points in the direction of the ground 68, the side blade 64 points in the direction of the traction vehicle 2 and somewhat upwardly, extending approximately in parallel to the opposite end of the swivel frame 7 pointing towards a conveyor 12.
The conveyor 12 is disposed between wheel axis 13 and vehicle frame 4. It has an inclination corresponding approximately to the swivel frame. A run 58 formed of upper run and lower run runs over deflecting axes 52 and 53 and over supporting rollers 54 and 55 and tensioning rollers 56 and 57. The direction of transport of the conveyor 12 and of the garbage pickup 9 disposed in the swivel frame 7 is the same and directed towards the rear end of the vehicle 1. The conveyor 12 also has laterally limiting directing plates 66 in similar fashion as the swivel frame 7.
A vertically adjustable garbage pickup is disposed below the vehicle frame 4. The garbage pickup includes an elevator with a front deflection axis 20 at the front end of the swivel frame 7 and a rear deflection axis 21 at the rear end of the swivel frame. The swivel frame 7 with the supply rotor 11 and the garbage pickup can be designed as a quickly exchangeable cassette unit.
The vehicle frame 4 is represented in lifted fashion with respect to the wheel axis 13 in FIG. 1. Two supporting arms 62 and 63 connected with the vehicle frame point from the vehicle frame in the direction of the wheel axis 13. A lifting cylinder 61 is disposed centrally between them. A lifting piston 60 is extended out of the lifting cylinder 61 almost completely, a holding element 59 partly encompassing the wheel axis 13 being disposed on its end. The holding element has a cross-section similar to an isosceles triangle. The lifting piston 60 is centrally connected to the base of this triangle.
The wheel 14 is almost completely visible when the vehicle frame 4 is lifted by means of the lifting means 60, 61.
A vertically adjustable actuating wheel 162 for depositing the vehicle 1 is disposed near the coupling means 3 vertically to the vehicle frame 4.
The beach cleaning vehicle 1 with the swivel frame 7 lowered to the ground 68 is represented in FIG. 2. The same elements are provided with the same reference numerals in accordance with FIG. 1 and will only be partly mentioned.
In this Fig. the loading area 5 is placed on the vehicle frame. The tipping means 36 moves its end 38 along the circular arc 72 when being actuated, the loading area 5 adopting approximately the position represented in FIG. 1 at the end of the circular arc. The tip 41 of the triangular frame part can be guided along the semi-circular arc 71 by means of the collecting receptacle swivel means 39. Whereas the collecting receptacle is pivoted as far beyond the loading area 5 as possible and the tip of the triangle 41 points in the direction of the swivel means 39 in the position of the collecting receptacle 6 shown in FIG. 1, the collecting receptacle 6 is disposed near the ground 68 below the rear deflecting axis 53 of the conveyor 12 in the position represented in FIG. 2. Upon actuation of the collecting receptacle swivel means 39, the surface centre 44 of the collecting receptacle 6 moves along the circle 69 up to the position of the collecting receptacle 6'. The end point 47 of the tipping link 46 moves at the same time along the arc 70. Due to the relative arrangement and length of support 42 and tipping link 46 described in FIG. 1, the corresponding guide arcs 69 and 70 intersect each other, and the collecting receptacle 6 points with its open end more and more in the direction of the loading surface 5 and can be emptied via a dumping edge 161 in the direction of the loading area 5.
The swivel frame 7 is lowered about the bearing point 8 with one end to the ground 68. A pickup V-ledge 10 disposed on the swivel frame 7 below the supply rotor contacts the ground 68 with its free end and the lateral blade 64 extends with its lower side substantially in parallel to the ground.
Upon the lifting of the swivel frame 7 in the direction towards the vehicle frame 4 by means of the actuating means 32, its end 33 mounted on the swivel frame 7 can be guided along the arc 73. The axis of rotation 18 of the supply rotor 11 can furthermore be pivoted across the swivel range 74 by means of the actuating means 29. The supply rotor is in a second operating position in the arrangement of the supply rotor represented in FIG. 2, while the positions 11' and 11" correspond to a first or a third operating position. They will be explained in greater detail in FIGS. 8 to 10.
As opposed to the representation of the vehicle frame 4 lifted in FIG. 1, the wheel axis 13 is mounted directly on the ends of the supporting arms 62 and 63 and the vehicle frame extends substantially horizontally.
A top view of the beach cleaning vehicle 1 is shown in FIG. 3. The vehicle frame 4 has a triangular frame section and an adjoining rectangular frame section connected with the coupling means 3. The triangular frame section is formed by two supports 81 and 82 extending symmetrically to the longitudinal direction 100 from the coupling means 3 in the direction of a first transverse bar 35. The tip of the triangle is disposed in the coupling means 3, while the base of the triangle is formed by the transverse bar 35. Longitudinal bars 75 and 76 adjoin the supports 81 and 82 in parallel to the longitudinal axis 100. The rectangular frame section is formed by these supports the transverse bar 35 and a transverse bar 78 disposed near the end of the vehicle. The longitudinal bars 75 and 76 have a distance corresponding to the distance of the wheels 14 and 14'. The loading area 5 is pivotably mounted on its rear ends 51 and 51', these ends projecting rearwardly beyond the transverse bar 78. While the transverse bar 78 extends from one longitudinal bar to the other, the transverse bar 35 being in parallel to it has a greater length. It projects with its ends 79 and 80 on both sides beyond the longitudinal bars by respectively the same length. The actuating means 32 and 36 are pivotably mounted on the outer ends of the transverse bar ends 79 and 80.
The loading area 5 is disposed above the frame 4 and is resting on it. A front wall 88, two side walls 87 and 89 and a rear wall 50 of the loading area 5 can be recognized in the top view shown in FIG. 3. The side walls or the front and rear wall are in parallel to the longitudinal bars 75 and 76 or the transverse bars 35 and 78 and form the rectangular loading area 5. The rear wall 50 extends at an angle to the vertical rearwardly in the direction towards the collecting receptacle 6 in accordance with the representation in FIG. 2. Whereas the upper edge of the rear wall 50 is disposed in front of the collecting receptacle, the lower edge which is closer to the collecting receptacle is disposed above an opening 90 of the collecting receptacle 6. The dumping edge 161 is thus located below the loading area 5. Dumping edge and the side of the collecting receptacle opposite to it extend substantially in parallel to the rear wall 50. The extension of the collecting receptacle 6 vertically to the longitudinal direction 100, i.e. its width, is slightly shorter than the inner distance of the side walls 87 and 89 of the loading area. The collecting receptacle 6 is centrally connected with the support 42 or 42' or the tipping links 46 and 46' with its transverse sides via the bearings 44 and 44' or 47 and 47'. The supports 42 and 42' extend in parallel to the tipping links 46 and 46' outside the side walls 87 and 89. Both supports 42 and tipping link 46 are connected 20 on their ends 43 and 164 with the side wall 87 and correspondingly with the side wall 89 on the other side. Laterally outside and in parallel to the side walls 87 and 89, collecting receptacle swivel means 39 and 39' are disposed on the side walls 87 and 89. The swivel means 39 extends between a first bearing point 40 and a second bearing point 41. The bearing point 41 is disposed above the support 42 in accordance with FIGS. 1 and 3 as tip of a triangle. The distance of support 42 and collecting receptacle swivel means 39 to the side wall 87 is substantially the same. The same applies mutatis mutandis to the collecting receptacle swivel means 39' on the other side wall 89 of the loading area 5.
A hydraulic covering 91 is disposed in front of the front wall 88 on the triangular frame section formed by the supports 81 and 82. The hydraulic covering extends symmetrically to the longitudinal direction 100, its side surfaces extending substantially in parallel to the supports 81 and 82 and projecting beyond them.
The covering 16 is disposed symmetrically to the longitudinal direction 100 below the hydraulic covering 91 and below the frame 4. The covering 16 projects slightly on both sides relative to the side walls 87 and 89 of the loading area 5, the actuating means 29 and 29' being disposed on these sides. The distance of these actuating means corresponds substantially to the distance of the collecting receptacle swivel means 39 and 39' or the distance of the supports 42 and 42'.
Bearing straps 19 and 19' are disposed on the front end of the covering 16 symmetrically to the longitudinal direction 100. The bearing straps are in engagement with bearing means 85 and 86 of a frame 84. The frame 84 extends in parallel to the front side of the covering 16 and laterally projects beyond it by two arms directed in the direction of the actuating means 29 and 29'. The driving means covering 17 is disposed on one side of the frame 84, a motor 83 projecting from the covering 17 in the direction of the longitudinal axis of the frame 84.
The beach cleaning vehicle 1 is represented in FIG. 4 in a top view of the garbage pickup 9, the conveyor 12 and the collecting receptacle 6.
Both the run 22 of the garbage pickup 9 and the run of the conveyor 12 are designed as sieve belts. They have a plurality of substantially rhombic openings.
Two lateral blades 64 and 64' outwardly bent symmetrically to the longitudinal direction 100 are disposed on the front side of the vehicle 1 on the ends of the V-ledge 10. The pickup width 92 of the lateral blades 64 and 64' corresponds substantially to the vehicle width 93. The V-ledge 10 projects from the garbage pickup 9 approximately beyond half of the longitudinal extension of the lateral blades 64 and 64' in the direction of the coupling means 3. The distance of the lateral blades is slightly smaller at the rear ends of the lateral blades than the width 95 of the upper run 22 of the garbage pickup 9. Directing plates 96 and 97 extending symmetrically to the longitudinal direction 100 adjoin these ends. They extend across a section directly adjoining the lateral blades 64 and 64' in parallel to the longitudinal direction 100, while they converge towards each other in the subsequent section. The distance of the directing plates 96 and 97 is somewhat smaller at the end of the garbage pickup 9 than the width 94 of the run 58 of the conveyor 12. The conveyor is disposed with its front deflection axis 52 below the rear deflection axis 21 of the garbage pickup in accordance e.g. with FIG. 1. The directing plates 96 and 97 are continued by parallel directing plates 66 and 66' of the conveyor up to its rear end. The collecting receptacle 6 is disposed on this end with a width 102, this width being greater than the width 94 of the upper run 58 of the conveyor 12.
A drive means 98 is disposed on one side of the rear deflection axis 21 for driving the garbage pickup 9. At least the supporting rollers 25 and 26 are drive-connected with the deflection axis 21 by means of driving connections 99.
The conveyor 12 also has a driven means 101 disposed on one side on its rear deflection axis 53.
Since the conveyor 12 is disposed between the wheels 14 and 14' above the wheel axis 13, its width 94 is smaller than the inner distance of the two wheels.
The supply rotor 11 is represented in FIG. 5. The frame 84 is substantially of a U-shape. A U-web 103 extends horizontally and in parallel to the swivel axis 120 of the rotor or the axis of rotation 18 of the rotor. The U-web 103 has U-legs 104 and 105 disposed rectangularly to it on its ends. They extend up to near above a rotor shaft 106 concentric to the axis of rotation 18. Bearing flanges 107 or 108 are disposed on the ends 109 and 110 of the U-legs 104 and 105. The bearing flanges are placed from the outside on the U-legs 104 or 105 and connected with them.
The axis of rotation 18 is mounted in the bearing flanges 107 and 108.
Concentric rotor end disks 132 and 133 are disposed on the axis of rotation 18. The rotor end disks limit the supply rotor 11 in the direction of the axis of rotation. A plurality of radially projecting tines 67 are disposed on the rotor shaft 106. Only a few tines are represented in FIG. 5 in order to illustrate this.
Bearing means 85 and 86 are disposed on the U-web 103 to mount the supply rotor 11 on the swivel axis 120.
The bearing means are formed in each case by a pair of bearing flanges 116, 117 or 118, 119. The bearing flanges have a corresponding opening to receive the swivel axis.
A drive means 111 is disposed on one side of the supply rotor 11. The drive means 111 comprises a motor 112 disposed above the U-web 103 and a drive disk 113 mounted on its driving axis. The drive disk 113 is connected with a drive disk 114 coaxially disposed on the axis of rotation via a V-belt 115.
A lateral view in particular of the flange bearing 108 is represented in FIG. 6. It is substantially of a U-shape. Oblong holes 123 and 124 are disposed in the U-webs symmetrically to an oblong groove 122 receiving the axis of rotation. A U-leg has an enlargement, in which a bore 30 is disposed. One end of the actuating means 29 can be mounted in this bore.
A U-leg 105 of the frame 84 of FIG. 5 is visible above the bearing flange 108. Both the oblong groove 122 and the U-leg 105 extend vertically in the direction 125. The bearing flange 119 extends at the upper end of the U-leg 105 in the direction 126. The bearing flange has a swivel bearing bore 121. The angle 127 is enclosed between the direction 125 of the oblong groove 122 and the direction 126 of the bearing flange 119.
The driving means of the supply rotor 11 is represented in FIG. 7. The rotor end disk 133 is disposed concentrically to the axis of rotation 18. Tines 67 project radially beyond the rotor end disk and define the circumferential line upon rotation in the direction 128.
The drive disk 114 is connected with the axis of rotation 18 coaxially to the axis of rotation 18. The drive disk 113 connected with the motor is disposed vertically above this drive disk. Both are drive-connected via a V-belt. A tensioning roller 131 staggered laterally with respect to the connecting line of the two drive disks 113 and 114 is disposed between the drive disks 113 and 114 to tension the V-belt.
The supply rotor is represented in a first operating position in FIG. 8. The same reference numerals designate the same elements as they are already known from the preceding Figs. They will only be dealt with partly.
The supply rotor 11 is pivoted forwardly about the swivel bearing axis 120 by means of the actuating means 29. The lowest point of the supply rotor 11 is located near the surface 68 and in front of the pickup V-ledge 10. The tines 67 engage in a layer of garbage 136 located on the surface upon counter-clockwise rotation 128. The garbage 136 is conveyed to the upper run 22 of the garbage pickup via the pickup V-ledge both by the rotation of the supply rotor 11 and by the movement of the vehicle in the direction 140. The garbage pickup transports the garbage away in the direction 137. In the operating position shown in FIG. 8 the pickup V-ledge 10 is disposed near the surface 68, but above this surface. The supply rotor can be pivoted forwardly that much by means of the actuating means 29 until the length of the piston 138 corresponds approximately to the length of the actuating means 29. In the position of the supply rotor being pivoted rearwardly to the greatest extent, the piston 138 is completely pulled into the actuating means 29. The entire swivel range of the supply rotor corresponds substantially to the swivel arc 74 of the axis of rotation 18.
A vertical fine adjustment of the axis of rotation 1B in directions 141 is possible by means of the oblong holes 123 represented in FIG. 6.
A wedge-shaped recess 139 is disposed in a lateral wall 134 of the baffle lining 15. It serves for receiving the axis of rotation 18 upon the pivoting of the supply rotor 11.
In the operating position represented in FIG. 8 the tines 67 do not engage into the sand 135 located below the surface 68.
Distance a, as seen in FIG. 9, is measured by forming a right angle between a substantially vertical line from the swivel bearing 120 to the ground surface and a substantially horizontal line from the tip 144 of the V-ledge 10, wherein a is equal to the distance between the tip of the V-ledge and the base point of the right angle. The distance a should be less than or equal to 1.5 r, wherein r is the radius of the rotor 131, and greater than or equal to 0.8 r, preferably a is approximately 1.15 r.
Distance b is the distance of the swivel bearing 120 from the horizontal line measured by a. The distance b is less than or equal to 3.0 r and greater than or equal to 2.0 r, preferably b is approximately 2.4 r.
Distance c, the distance between the swivel bearing and the plane determined by the V-ledge is less than or equal to 3.2 r and greater than or equal to 2.5 r, preferably c is approximately to 2.8 r.
Distance e is the distance between the periphery of the supply rotor and the plane determined by the V-ledge.
A second operating position of the supply rotor 11 is represented in FIG. 9. The pickup V-ledge is introduced with its tip 144 into the sand up to the depth d in this case. Both sand 135 and garbage 136 is located between the pickup V-ledge 10 and the supply rotor 11. The supply rotor 11 is pivoted rearwardly that much in this operating position that the distance e between the circumferential line 129 and the V-ledge 10 is minimal. Further characteristic magnitudes according to the invention are the distance a of the tip 144 of the pickup V-ledge 10 and the perpendicular base point 143 of the perpendicular 142 passing through the swivel axis 120 and the distance b or c of the swivel axis 120 from the perpendicular base point or the plane formed by the pickup V-ledge 10.
The pickup V-ledge encloses an angle α with the horizontal, which is greater by the angle 145 than the angle β enclosed between upper run 22 and the horizontal. Distance e is about 1/4 to about 1/6 of the radius of the rotor.
The supply rotor 11 is represented in a third operating position in FIG. 10. The piston 138 is completely introduced into the actuating means 29 and the supply rotor is disposed in its position pivoted rearwardly to the greatest extent. The circumferential line 129 of the supply rotor almost contacts the covering 16 from below and the axis of rotation 18 is introduced as far as possible into the cutout 139 of the side wall of the baffle lining.
Circumferential line 129 and upper run 22 are disposed at the distance f in the third operating position. The distance f is approximately twice as great as the distance e between circumferential line and pickup V-ledge 10 in the second operating position. As can be recognized by means of the envelope 163 of the circumferential line 129 during pivoting, the distance e is the minimum distance.
A front view of the wheel axis 13 is represented in FIG. 11. A bottom wall 146 of the loading area 5 extends horizontally and rests on the transverse bar 78 of the vehicle frame. The vehicle frame is laterally enclosed by the longitudinal bars 75 and 76. The side walls 82 and 87 enclosing the loading area 5 in vertical direction are disposed above the longitudinal bars 75, 76 and outwardly staggered with respect to them.
Lifting cylinders 61 or 61' are attached to the longitudinal bars 75 and 76 by means of upper lifting means fastenings 152 and 153 resting against the longitudinal bars. The lifting cylinders are directly disposed below the longitudinal bars 75 and 76 and, like them, they are symmetrically disposed to the central vertical axis 164 of the vehicle. The lifting pistons 61 and 61' are fastened to the wheel axis 13 by means of holding elements 59 and 151 between the wheels 14 and 14' directly adjacent to them. Lower lifting means fastenings 149 and 150 are formed on each of the holding elements. The lifting pistons movable in the lifting cylinders are mounted on the same. The ends of the lifting pistons 61 and 61' are guided through lifting piston guides 147 and 148 above the lower lifting means fastenings 149 and 150.
A lateral view of the lifting means is represented in FIG. 12. The upper lifting means fastening 153 is visible below the longitudinal bar 76. The upper lifting means fastening is substantially formed by a profile disposed laterally on the longitudinal bar 76 in parallel to the longitudinal bar 76. A bore 154 is centrically formed in this profile for mounting the upper end of the lifting cylinder 61. Two supporting arms 62 and 63 pointing in the direction of the wheel axis are disposed on the ends of the profile on the longitudinal bar 76. A profile 148 is mounted near the free ends of the supporting arms between the same for fixing the lower end of the lifting cylinder 61. The lifting cylinder 61 itself extends centrally to the supporting arms 62 and 63 enclosing substantially a triangle with the longitudinal bar 76. In the representation according to FIG. 12 the lower bearing point of the lifting means is disposed directly below the profile 148. The holding element 59 resting against the free ends of the supporting arms 62 and 63 is represented on the free ends of the supporting arms 62 and 63. Its cross-section has substantially the shape of an isosceles triangle. The free ends of the supporting arms 62 and 63 rest against the ends of the base line of this triangle. The lower bearing point 150 of the lifting means is disposed centrally between these free ends in the centre of the base line. The two legs of the triangle point in the direction of the wheel axis 13 and encompass it partly.
The lifting means with maximally extended lifting piston 60 is represented in FIG. 13. The same reference numerals designate the same elements in accordance with FIG. 12. They will only be dealt with partly.
The longitudinal bar 76 is represented upwardly lifted by the distance g with respect to the wheel axis 13. The free ends 157 and 158 of the supporting arms have bearing journals 155 and 156. They are disposed in parallel to the lifting cylinder 61 or the lifting piston 60 and point towards the holding element 59. Corresponding bearing openings 159 and 160 are disposed in the holding element, which are in engagement with the bearing journals 155 and 156 in the representation according to FIG. 12. | A vehicle for beach cleaning has a vehicle frame with at least one wheel axis disposed on it. Garbage is picked up from the beach by a vertically adjustable garbage pickup and delivered to a conveyor adjoining the garbage pickup and conveying the garbage taken to a collecting receptacle disposed at the rear end of the vehicle frame. A supply rotor is allocated to the pickup area of the garbage pickup.
In order to improve the supply, the pickup and the transport of refuse and the separation of refuse and sand and the disposal of the pollutants, a swivel frame supporting the garbage pickup and the supply rotor is lowerably mounted on the vehicle frame for vertical adjustment, the supply rotor being mounted on the swivel frame pivotably across a swivel range comprising different operating conditions by means of links and being in particular counter-clockwise rotatable about an axis of rotation mounted on the links. | 50,257 |
FIELD OF THE INVENTION
This invention relates to the field of integrated circuit packaging and, more specifically, to an arrangement which allows multiple semiconductor chips to be housed in a single package. The invention is most particularly suited for plastic packaging of integrated circuits.
BACKGROUND OF THE INVENTION
Semiconductor integrated circuits, or chips, are small (usually square or rectangular) pieces of semiconductor material (e.g., silicon or gallium arsenide) with dimensions typically on the order of 2-7 millimeters on a side. Semiconductor chips may contain complex circuitry formed of hundreds of thousands of individual electronic components. Naturally, to utilize such a chip, connections must be made between the chip itself and external circuitry. To facilitate use of the chip and the making of such connections, the chip is usually packaged in a housing equipped with a lead structure incorporating electrical leads, each of which is at one end electrically bonded to the chip and at its other end serves as a connection point to other circuits. Inside the package, these leads are connected to individual terminal sites, known as bonding pads, on the chip. A variety of conventional techniques are available to accomplish this bonding.
A leadframe typically carries only one chip. Thus, interconnections from chip to chip usually are made exteriorly to the chip package. While this provides flexibility in arranging interchip connections, there are situations in which such flexibility is unnecessary and adds to the cost of a product using the chips. Sometimes two chips are designed to be connected together in a particular fashion and advantages would accrue from connecting the chips within a single package, so that two chips could be sold as a single unit. Of course, there are instances when the circuitry on two smaller chips can be combined to be fabricated as a single chip in a single package. This is not possible, however, when the two constituent chips are manufactured using different process technologies.
To assemble two chips on a single leadframe, the chips must be placed side by side on the leadframe's die attach paddle. However, this approach cannot be used with chips which are backside biased, unless their biasing needs are the same under all conditions.
To solve this problem, some companies have removed the usual metal die attach paddle in the leadframe assembly and have replaced it with a dielectric substrate, onto which multiple chips may be mounted. The dielectric substrate is typically a ceramic or resin. The use of a dielectric is necessitated by the requirement to electrically isolate the substrates of the chips, so they may be separately backside biased. This solves the technical problem, but at considerable expense.
Accordingly, it is an object of the present invention to provide an inexpensive technique for assembling multiple integrated circuit chips on a single leadframe.
Another object of the invention is to provide a multiple chip mounting arrangement on a single leadframe which does not require removal of the metal die attach paddle of the leadframe or use of a dielectric substrate as a foundation for mounting the chips.
SUMMARY OF THE INVENTION
The foregoing objects are achieved in an assembly wherein the die attach paddle of a conventional leadframe is cut to form two electrically isolated die attach paddles and a dielectric tape is applied to one side of the two die attach paddles, spanning the space between them, providing physical support and substantially preventing cantilevered or twisting motion of the die attach paddles relative to the remainder of the leadframe assembly.
The die attach paddles may not be electrically isolated in the strictest sense of that term until the various leads of the leadframe are separated from the side rails. Hence, it should be understood that when the die attach paddles are referred to herein as being electrically isolated, that term is meant to indicate that the die attach paddles will be electrically isolated once the side rails are removed and all metal bridges between the leads are cut.
The invention will be more readily understood from the detailed description, which should be read in conjunction with the accompanying drawing. The detailed description is presented by way of example only, with the invention being defined only by the appended claims and equivalents thereto.
BRIEF DESCRIPTION OF THE DRAWING
In the drawing,
FIG. 1 is a top plan view of a typical prior art leadframe strip or a plurality of leadframe assemblies used for production of integrated circuits in plastic packages;
FIG. 2 is a cross sectional view of a single leadframe of FIG. 1, taken alone the lines 2--2 thereof, and showing in phantom two semiconductor chips p aced thereon;
FIG. 3 is a top plan view of a partially completed leadframe assembly according to the present invention;
FIG. 4 is a simplified cross-sectional view of the partially complete leadframe assembly of FIG. 3, taken alone the lines 4--4 thereof;
FIG. 5 is a bottom plan view of a completed leadframe assembly according to the present invention;
FIG. 6 is a top plan view of a completed leadframe assembly according to the present invention, with two chips mounted thereon;
FIG. 7 is a simplified cross sectional view of the assembly of FIG. 6, taken alone the lines 7--7 thereof;
FIG. 8 is an expanded layout of the apparatus of FIG. 6, showing the internal electrical connections established between the two chips o the leadframe assembly; and
FIG. 9 is a top plan view of a leadframe assembly with four die attach paddles according to the present invention.
DETAILED DESCRIPTION
FIG. 1 shows a typical prior art leadframe strip 10, which is stamped from sheet metal. The leadframe strip 10 comprises a pair of side rails 12 and 14, each having sprocket holes, such as 16 and 18, at regularly spaced intervals. The sprocket holes cooperate during the chip assembly process with sprocket teeth in a mechanism for moving the leadframe strip through appropriate processing equipment. A leadframe strip generally has a large number of leadframe assemblies, such as the two assemblies 20 and 22, suspended between the side rails at regular intervals.
Referring to representative leadframe assembly 20, each leadframe assembly comprises a die attach paddle 24 supported from the side rails 12 and 14 by thin metal bridges 26 and 28, respectively. A plurality of connection pins or leads 30A, 30B . . . 30n are also suspended between the side rails via bridges 31 and are arrayed around the die attach paddle. These connection pins are later bonded to small wires which connect them to bonding pads, or terminals, on the semiconductor chip(s). Later in the assembly process, the bridges 26, 28 and 31 are severed, detaching the side rails 12 and 14 from the connection pin strips and electrically isolating each of the connection pins and the die attach paddle.
When two integrated circuit chips, such as chips 40 and 42, are mounted on opposite ends of die attach paddle 24, an arrangement such as that shown in FIG. 2 results. Since the die attach paddle is metal, chips 40 and 42 are, in such configuration, not electrically independent. If a bias voltage is applied to die attach paddle 24, it affects both chips 40 and 42. This, as noted above, is a situation that greatly restricts the flexibility of selecting two chips for assembly into the same package, since the two chips must be capable of operating with the substrate bias. Often, two chips which are to be closely interconnected must maintain independent biases.
According to the present invention, this problem is solved as shown in FIGS. 3-8. The first step in creating the assembly of the present invention is to provide a modified leadframe assembly, wherein the attach paddle is formed as or cut into two (or more) separate die attach paddles, as indicated, for example, by the paddles 24A and 24B of FIG. 3. A single die attach paddle 24 may be cut into two or more constituent and electrically isolated die attach paddles, or die attach paddles 24A and 24B can be manufactured separately from the beginning. Separate die attach paddles 24A and 24B can be the same size or different sizes. For purposes of generality, they are indicated in the drawings to be of different sizes. The resulting arrangement appears in a simplified cross sectional view in FIG. 4, wherein the space 44 between the two die attach paddle members 24A and 24B is more apparent. Again, chips 40 and 42 which are to be mounted on the respective die attach paddles are shown in phantom and in diagrammatic form only. This structure 10 allows separate backside biasing of the two chips, but it is impractical. The leadframe is formed from a very thin sheet metal stock, so the bridges 26 and 28 (not shown in FIG. 4, but identical to those shown in FIG. 1) are inadequate to rigidly support the die attached paddles 24A and 24B which, due to the gap 44, are now cantilevered from the siderails. The twisting and moving of the two die attached paddles in that situation is intolerable.
As a next step, therefore, in fabrication of the present invention, a strip of polyimide tape is applied, using a non conductive adhesive such as a silicone adhesive, to the reverse sides of the paddles 24A and 24B (i.e., the side which does not receive the chips). This is represented by the tape 50 in FIG. 5. A suitable material is Kapton® tape manufactured by E. I. duPont de Nemours of Wilmington, Del.
After the polyimide tape has been secured, providing structural stability to the assembly, the two chips are glued to the top surfaces of the respective die attach paddles 24A and 24B, as shown in FIG. 6. The resulting arrangement is shown in the simplified cross-section of FIG. 7.
Finally, the two chips 40 and 42 are wired to the connection pins, as shown in FIG. 8 by, for example, the wires 60A and 60B. They are also wired to each other by connecting appropriate conductors indicated generally at 62, between opposing bonding pads on the two chips. Lastly, the entire assembly is encapsulated in a plastic package.
The polyimide tape may be obtained with an already applied coating of a pressure sensitive adhesive, so that it can simply be pressed in place. Alternatively, the polyimide tape may be secured to the die attach paddles with a heat activated adhesive.
A prime benefit of this invention is its low cost. A total of 1-2¢ is added over the cost of the standard leadframe of the type shown in Fiq. 1. By contrast, the use of a ceramic substrate adds about 15-25¢ to fabrication costs, and the use of a resin substrate adds about 15 to fabrication cost.
Up to four (or more) chips may be placed in a single package using this approach, using (for example) the arrangement shown in FIG. 9, where four separate die attach paddles 70A, 70B, 70C and 70D each have one bridge or tie bar (72A, 72B, 72C and 72D, respectively) connecting them to the side rail of the leadframe strip. A single strip of dielectric tape 74 may be applied across the backs of all the attach paddles. This can permit extremely complex functionality to be provided in a single package at low cost.
Having thus described the inventive concept and two embodiments which are shown by way of example only, it will be readily apparent that various alterations, modifications and improvements will occur to those skilled in the art. Such alterations, modifications and improvements are intended to be suggested herein, although not expressly stated. Accordingly, the invention is limited only by the following claims and equivalents thereto. | The foregoing objects are achieved in an assembly wherein the die attach paddle of a conventional leadframe is cut to form two electrically isolated die attach paddles and a dielectric tape is applied to one side of the two die attach paddles, spanning the space between them, providing physical support and substantially preventing cantilevered or twisting motion of the die attach paddles relative to the remainder of the leadframe assembly. | 11,892 |
BACKGROUND OF THE INVENTION
The present invention relates to a sieve belt comprised of a multiplicity of helices made of thermosettable synthetic resin material, especially synthetic resin wire, with adjacent helices intermeshed with each other so that the windings of one helix enter between the windings of the adjacent helix and pintle wires which are inserted through the respective channels thus formed by the intermeshed helices. For controlling the air permeability of the sieve belt the hollow interiors of the helices are filled with a filler material. The invention further relates to a method for producing such a sieve belt.
Due to varying requirements, it is desirable to be able to change the air permeability of sieve belts made of synthetic resin helices. In the sieve belt disclosed in U.S. patent application Ser. No. 111,497 filed Jan. 11, 1980 now U.S. Pat No. 4,346,138 in the name of Johannes Lefferts and assigned to the same assignee as the present application, the spirals or helices are open and the air permeability is very high. In papermaking machines operating at very high speeds, high air permeability may be disadvantageous since it causes very intense air circulation which may disturb the paper web. The air permeability could be reduced by inserting stiff monofilaments into the interiors of the helices from the sieve belt edges or by inserting spun yarns or multifilament yarns by means of a threading device. However, such inserted material would lie straight in the interiors of the helices so that a large amount of filling material would be required to appreciably reduce the air permeability. Moreover, the large amount of filler material would greatly increase the weight per unit area of the sieve so that the insertion of the filler material and generally the handling of the sieve would become cumbersome, especially in the mounting of the sieve belt on the papermaking machine. The later introduction of filler material into the assembled sieve belt meets with difficulties and brings about disadvantages. Either the filler materials are introduced into the interlocked helices before the sieve belt is thermoset or the filler materials are inserted into and threaded through the channels after thermosetting. In both cases, the sieve belt must be thermoset a second time after insertion of the filler material since otherwise, the filler material might shrink later on under the influence of the papermachine temperature. Two thermosetting steps are very expensive and time consuming. Moreover, when the filler material is introduced prior to thermosetting of the sieve belt, there is the risk that the helices may shift over the pintle wires which are still straight at that stage so that humps and buckles may develop in the sieve belt. Furthermore, in both modes of operation, a certain length of filler material would have to extend laterally from the sieve belt so that after thermosetting and shrinkage of the filler material, the sieve belt will still be filled across its entire width. Such a method would be complicated and susceptible to trouble.
Another disadvantage resides in the fact that the filler material extends straight through the helices so that it can easily slip out of the sieve belt. For instances, if the edge of the sieve belt is damaged in the papermaking machine, the filler material can easily get caught on parts of the papermaking machine and will then be pulled out of the sieve belt. This may happen when the sieve belt laterally chafes against the machine.
SUMMARY OF THE INVENTION
The present invention provides a new and inproved sieve belt having reduced air permeability which can be produced quickly and economically.
According to the present invention, the filler material, for example multi-filament or mono-filament yarn, spun yarn or taped yarn, is disposed in the hollow interiors of the helices in a completely untensioned state in a stuffed or crimped condition. Since no tension is exerted on the filler material it expands in a transverse direction thereby filling the hollow interiors of the helices better and more uniformly than a tensioned yarn. Especially with the use of softly twisted multi-filament yarns and spun yarns as filler materials, the individual fibers are uniformly distributed throughout the hollow space so that the sieve belt does not have any open areas.
The present invention provides a new and improved method for assembling sieve belts with filler material in that the filler material contained in the hollow interiors of the helices yields as the helices are interlocked and can be easily pushed aside thereby permitting the use of already filled helices for the manufacture of the sieve belt. The channel into which the pintle wire is to be inserted is formed without any particular difficulties. Straight mono-filaments or multi-filaments, when used as filler material, would not make room for the formation of the channel and would offer considerable resistance to interlocking of the helices. If such a filler material were used it could be introduced into the hollow helix interiors only after interlocking of the helices.
The aforementioned difficulties resulting from the filling of the helices after they have been interlocked to form the sieve belt are not encountered in the manufacture of the sieve belt according to the present invention. Although minor shrinkage of the filler material may occur on thermosetting of the filled sieve belt, sufficient length of the filler material is available to allow for such shrinkage, that is, after thermosetting of the sieve belt the filler material is still more or less undulated rather than straight in the hollow interior of the helices. This undulation causes sufficient friction in the interior of the helices to prevent slipping of the filler material out of the helices even if the edges should be damaged. This is significant particularly with the use of smooth material, for example mono-filaments, twisted mono-filaments or multi-filaments. Slippage of the filler material out of the helices can also be prevented by forcing the material into the interior of the helices. However, in practice this cannot be realized because the sieve belts would become very heavy and the helices so plugged as to be no longer capable of being interlocked.
In principle, there are two possibilities for filling the interiors of the helices before interlocking them, namely, either to wind the synthetic resin wire around the filler material when the helices are formed or to fill the helices with filler material after their formation but prior to interlocking. In the second case, the helices can be filled so that first one or more monofilament wires are threaded into the interior of the helices and thereafter the filler material is deformed under external influences, for example by wrapping the helices with a yarn so that the wraps of the yarn come to lie between the windings of the helices and then tensioning the yarn in a direction normal to the longitudinal axis of the helix. In this manner, the yarn tends to pull the filler material somewhat out between the helix windings normal to the helix axis. In this state, the filler material is thermoset. Another possibility is to deform the filler material from the outside by gears or by impressing other helices. Finally, a yarn composed of a less shrinkable and a highly shrinkable component may be employed. Such a yarn will crimp automatically during thermosetting. The same effect can be obtained with the use of bicomponent filaments.
The sieve belt according to the present invention is especially suited for use with a paper machine sieve and is especially advantageous when used in the pressing section of a papermaking machine.
The foregoing and other objects, features and advantages of the invention will be apparent from the following more particular description of preferred embodiments of the invention as illustrated in the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of a sieve belt having filled helices showing a comparison between straight filling material and untensioned or crimped filling material.
FIG. 2 is a longitudinal sectional view of the two arrangements shown in FIG. 1 comparing the helices filled with a straight tensioned yarn and the helices filled with untensioned filler material thermoset in a wavey configuration.
FIG. 3 is a sectional view similar to FIG. 2 showing how the filler material extends beyond the helix arcs when the filler yarn is initially provided with a greater excess length.
FIG. 4 is a schematic view showing the apparatus for manufacturing filled helices for a sieve belt according to the present invention.
DETAILED DESCRIPTION OF THE INVENTION
As described in prior U.S. application Ser. No. 111,497 (supra) the sieve belt is comprised of a plurality of intermeshed helices joined together by a plurality of pintle wires, one in each channel formed by two adjacent helices.
As illustrated in FIG. 1 of the present application, the hollow interior of each helix is filled with a filler material. The spaces A and B of the two helices at the left of FIG. 1 are filled with straight mono-filament yarn while the spaces C and D on the right of FIG. 1 are filled with a bulky multi-filament or spun yarn. It is clear that voids are still present in the interior spaces A and B, for example where the helix arcs of adjacent helices intermesh, while the bulky filler material completely fills the interior spaces C and D. From FIG. 2 it may be seen that the filler material on the right not only fills the hollow interiors of the helices but that it also partially enters between the helix arcs. In this manner, the surface of the sieve belt is closed and equalized and the chance of very slight markings caused by the sieve belt is further reduced. Moreover, such a complete filling of the spaces between the helix arcs enlarges the supporting area of the sieve belt which promotes drying of the paper. By providing the filler material with an especially great excess length, it is possible that the filler material will even extend beyond the arcs as seen in FIG. 3. This imparts a soft surface to the sieve belt.
An arrangement for producing filled helices is shown in FIG. 4. The portion of the method for producing the helix is similar to that disclosed in prior application Ser. No. 111,497 (supra). The apparatus comprises a rotating mandrel D and a cone K which are guided in a reciprocating manner at one end of the mandrel 20. The helix is produced by feeding a first filament T from a package P to the rapidly rotating mandrel D. The first filament T is thus wound onto the mandrel 20 by means of the cone K which reciprocates rapidly and the thus formed helix is pushed across the mandrel past heating means to the righthand side as viewed in FIG. 4.
The arrangement according to the present invention further provides for a filler yarn G which is withdrawn from a package S and passes between rolls W which are adjustable as to speed. The package S and the rolls W are connected to the shaft of the mandrel D so as to rotate as a unit with the mandrel D and the cone K about the longitudinal axis of the mandrel D. Moreover, the package P for the filament T from which the helices are formed is arranged so that the filament T first comes into contact with the cone K at the point P1 in the outer third of the cone K, then passes over the inner part of the cone K and is finally wound about the mandrel D. The filler yarn G contacts the cone K at the periphery thereof and is engaged by the filament T at the point P1, that is, it is clamped between the filament T and the surface of the cone K. As the filament T slides over the inner part of the cone K, it takes along a portion of the filler yarn G disposed between the points P1 and P2. The point P2 is located at the transition between the cone K and the mandrel D, that is, at the point where the winding of the helix starts. By adjusting the speed of the rolls W the length of the piece of filler yarn G which is taken along by the filament T can be controlled and is then placed within the winding of the helix. The filler yarn G is urged laterally outwardly between the windings of the filament T and the auxiliary wire H and is set in this condition by the heating means. The excess length of the filler yarn G is thermoset in this way, that is, the excess length of the filler material is consumed in the crimping of the material. After the auxiliary wire H has left the mandrel D and the helix has been pushed from the mandrel D the thermoset crimps of the filler yarn G slip into the interior of the helix and spread out in the hollow interior of the helix.
The extent of crimping of the filler yarn G is determined by the peripheral speed of the rolls W as mentioned before. The extent of crimp generally varies between 1.2 and 8, that is, in a given length of the helix 1.2X to 8X this length of filler yarn is disposed. Lower values for the crimp are also possible.
To complete the manufacture of the sieve belt, the filled helices are pushed laterally one into the other so that the windings of one helix come to lie between the windings of the adjacent helix. The helices are pushed into one another to the extent necessary to form a channel into which a pintle wire is inserted for firmly locking the helices together. Finally, the sieve belt is thermoset under tension so that the helices are somewhat buried in the material of the pintle wire thereby causing the pintle wire to assume a wavy configuration. As the helices are thus interlocked, the filler material in one helix is pushed away by the windings of the other helix. Since the filler material is very bulky, it does not offer too much resistance and yields to the pressure.
The air permeability of the sieve belt is determined, inter alia, by the type of filler material and the extent of its crimp. Thus, for example, in a sieve belt having a thickness of 2.5 mm and comprised of helices having a wire thickness of 0.7 mm, pintle wire having a wire thickness of 0.9 mm and 20 pintle wires per 10 cm of sieve length, the air permeability is 320 m 3 per m 2 per minute at a pressure differential of 12.7 mm water head. When the same sieve belt is made from helices filled with two textured polyamide multi-filament yarns of 1300 dtex each having a 1.5 crimp, the air permeability drops to 140 m 3 per m 2 per minute.
Other types of filler material may be used such as one having a linear textile structure. "Tape yarn" is also usable and is chemical tape (extruded and slit), spliced tape or woven tape.
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those in the art that the foregoing and other changes in form and details may be made therein without departing from the spirit and scope of the invention. | The sieve belt is comprised of a multiplicity of helices made of thermosettable synthetic resin material which are interlocked with each other by inserting a plurality of pintle wires into the channels defined by the overlapping helices. For controlling the air permeability of the sieve belt, the hollow interiors of the helices are filled with a filler material comprised of crimped synthetic filaments. | 15,156 |
BACKGROUND OF THE INVENTION
The present invention relates to an improved method for accelerating the freezing of ice, initially formed by the freezing of a sea water spray or impounded sea water, and more particularly to an improved method to form an engineered load-bearing ice structure of high quality and in a shorter time than normally could be obtained.
Rapid freezing of sea water is important in certain applications such as the construction of load-bearing ice structures in offshore Arctic regions where such structures are employed in conjunction with hydrocarbon exploration and production and in the construction of airfields, roads, camps and the like. In these applications, sea water is used exclusively as the aqueous medium and construction is usually started as soon as the ambient air temperature is sufficiently low to cause freezing of the sea water. It is economically advantageous to be able to cause the freezing of sea water to proceed as rapidly as possible so that load-bearing structures may be constructed in a relatively short period of time so as to extend to the maximum degree possible the utility of the manufactured structure.
A method commonly employed to form ice structures involves the propelling of sea water through the air as essentially a stream of sea water and over significant horizontal distances. The volume of the continuous stream may range up to 30,000 gallons per minute from a single nozzle used to propel the salt water over the needed distance. The air, by virtue of its low temperature with respect to the nominal freezing temperature of sea water (-1.6 to -2.0 degrees C depending on salinity), acts as a coolant. The formation of droplets and the interaction of the sea water stream/droplet spray with cooler air results in freezing of the projected droplet spray. The efficiency of freezing depends on efficient heat exchange between the sprayed droplets and air. Formation of water droplets and the size of the droplets ultimately governs freezing efficiency at any ambient air temperature less than the nominal freezing temperature of the sea water. At the spray nozzle, the bulk of the sea water is in the form of a solid stream of water having high momentum in order to cover the desired relatively large horizontal distance. In the vicinity of the nozzle, shear and turbulent forces along the periphery of the water stream initiate droplet breakup and segregation. Along the trajectory of the stream/droplet spray, wind forces and gravitational forces promote increasing droplet breakup and segregation. Maximum droplet breakup, in the absence of significant wind forces, occurs at the apogee of the stream trajectory. The surface tension of the sea water is the fundamental property which governs how soon discrete water droplets will form and their size distribution for any imposed set of ambient conditions.
Load-bearing ice structures are also commonly built by forming a berm or dike and then flooding the impounded area with sea water, the process being repeated, after freezing of the sea water, as necessary until a desired thickness of ice has formed. Ice structures which are used as the support unit for large drill rigs are themselves large. Construction may require one or more months. It is necessary, therefore, to accelerate the ice construction phase so as to allow maximum time for drilling activities prior to the onset of the Spring thaw. The more or less routine application of flooding-spraying technology in conjunction with offshore Arctic application is described in the prior art, U.S. Pat. No. 4,048,808 being a typical example.
In accordance with this invention, it has been discovered that the governing property of a high volume sea water stream is formation of water droplets varying in a size from 1 to about 3 mm in diameter. These droplets freeze in the form of hailstones, which are rounded or spherical masses of ice. The interior of the frozen droplets commonly contain liquid water of high salinity consistent with finite freezing rates and thermodynamic constraints that govern the freezing of saline solutions which have a true eutectic. Successful ice construction requires that the projected sprayed material which falls to the surface have a liquid content. Some droplets crush on impact releasing additional brine. The fallen material undergoes partial melting and then refreezing. Excess brine drains either away from the structure by virtue of its reduced freezing temperature, caused by partial evaporation during flight and by salt rejection that occurs simultaneously with freezing or remains entrained in the porosity of the spray ice. On impact with the ground, the brine is released and there is some partial melting of the frozen material. The newly formed slush then refreezes upon exposure to ambient temperature air. The refreezing which occurs after impact is the phenomena that is responsible for strength development in sprayed ice.
In ice construction, where the aim is to build a substantial load-bearing structure of a relatively large dimension, dry snow is undesirable and detrimental because snow contributes to a general weakening of the manufactured structure and snow does not possess the substantial strength of ice.
Sea water spray construction of ice islands is a complex process that includes several important phenomena which collectively control the properties of the manufactured structure. Sea water is usually applied as a spray. The freezing of the spray is controlled by ambient climactic conditions, the volume of spray and the size distribution of water droplets within the spray. Spray ice, which consists of a mixture of ice and brine and/or precipitated salt may, depending upon ambient temperature and wind conditions, partially remelt upon impact and then slowly refreeze. Typically, spray ice construction is a cyclic process where sea water is sprayed for a period of time and then spraying is terminated to allow refreezing of the sprayed surface. The cycle is then repeated as necessary to produce the desired structure. Internal structure of spray ice reflects the cyclic nature of its formation.
Manufactured ice consists of alternating layers of relatively hard ice immediately underlain by a much thicker layer of much softer material. The internal structure of an ice island is a direct reflection of the techniques used for its construction.
The basic methodology for construction of an ice island using sea water spraying techniques, consists of freezing a sea water spray by the cooling action of ambient temperature air on the spray. Since sea water must be sprayed in large volumes over considerable horizontal distances, nozzles are selected primarily for their throwing or spraying distance. This requirement places rather stringent controls of the size of water droplets which form in the spray. It is the discrete water droplets which ultimately freeze and fall to the ground.
As droplets form in the spray, they freeze in the form of spherical hailstones consisting of ice. The cores of many of the larger hailstones contain brine significantly more saline than the source sea water due to partial evaporation of sprayed sea water and salt rejection during the freezing process. Upon impact, some hailstones shatter releasing brine. Depending upon ambient temperatures, some free, unfrozen brine may also reach the ground unfrozen but concentrated by partial evaporation. The spray may reach heights above ground surface of two hundred (200) feet or more. Air temperature differences between the maximum height attained by the spray and ground level can also encourage partial remelting of spray ice.
The saline brine contacts previously sprayed and frozen material and causes partial melting of this material. The residue brine as a consequence of the partial remelting decreases in salinity. The newly formed slush is then slowly refrozen by the action of the ambient air. The slush refreezes from its surface downward. As the initial upper surface refreezes, lower levels of the slush are insulated from direct air contact and they freeze at a lower rate. As a result of this process, the sprayed ice consists of cyclic deposits of hard ice immediately underlain by softer material that was prevented from fully freezing. If spraying is stopped and then resumed at a later time, the newly fallen material will cause partial remelting of the previously frozen surface. Thus, the thickness of the hard ice surface is probably never as great as it was when originally formed just before resumption of spraying.
A thermal gradient exists from the sea water-ice interface to the ice-air interface. Thermistor arrays are usually buried in an ice island during construction, and temperature data derived from these devices graphically demonstrate the heat transfer phenomena. Thus, partial remelting of newly formed spray ice is also a reflection of heat transfer from the warmer sea water to the colder free ice surface.
The primary factors that govern spray ice construction can be summarized as follows: (1) the freezing dynamics of a sea water spray, and (2) the refreezing of spray ice.
In the past, researches have concentrated on understanding spray freezing phenomena. Essentially, no attention has been devoted to the problem of spray ice refreezing. The dominating importance of spray ice refreezing can be readily understood when it is noted that during a typical twenty four (24) hour period, sea water may be sprayed for ten (10) hours or less whereas the remainder of the twenty four (24) hour period is spent waiting for spray ice to refreeze. Any improvement resulting in a diminution of the time required to refreeze spray ice may have dramatic and significant impact on overall construction time and cost.
The time required to refreeze spray ice after a spraying period is the major factor that influences the time required to build an ice structure. It would be desirable, therefore, to provide improved and relatively simple methods for accelerating spray ice refreezing.
SUMMARY OF THE PRESENT INVENTION
In brief, the present invention focuses on acceleration of the formation of load bearing ice structures and more particularly to the acceleration of the refreezing of ice structures during their construction. In one form, the method of this invention involves use of a conveyance to move a ventilation fan across the newly deposited ice surface. Normally, refreezing of spray ice occurs by ambient air cooling. Wind blows cool air horizontally across the ice surface. However, the efficiency of the process is limited by thermal effects which retard heat heat transfer when the ice surface initially refreezes thereby insulating lower lying material from the direct cooling effects of ambient temperature air. Furthermore, wind velocity in the boundary layer adjacent to the ice surface may be a small fraction of wind forces at higher levels above the ice surface.
The method of the present invention involves forced refreezing by directing a vertical column of air downward on the ice surface with sufficient force to disrupt the surface material and, thereby, to cause cooling to a greater depth than would be otherwise possible. The roughened air-blown surface may then be resmoothed by a rake attached to the ventilation fan conveyance. Another approach involves mounting the fan directly on self-contained power units. Other methods for direction of air columns downward in a spray ice surface include use of helicopters of hydrofoils operated over the desired area or tracked vehicles or use of winches and cranes to support or transport any one of a number of different well known devices to move a vertical air column across the spray ice surface.
Ice construction using flooding techniques is effective and routinely practiced in Arctic regions because it is possible to freeze a shallow impounded mass of sea water. Cooling occurs at the water-air interface. An intrinsic property of water is the attainment of maximum density at a temperature slightly above its freezing temperature. This property allows for more uniform cooling of a large impounded water mass.
The forced refreezing method can, therefore, equally be applied to the accelerated freezing of impounded sea water.
Application of the forced refreezing method, whether applied to the refreezing of spray ice or to the accelerated freezing of impounded sea water, will significantly improve the mechanical properties of the ice structure, where improvemnt in load-bearing strength and shear resistance is desirable. This improvement is obtained because refreezing of spray ice or accelerated freezing of impounded sea water, occurs over a greater depth range, by virtue of the forced refreezing of the downward directed air column which contacts the spray ice or impounded sea water over a greater vertical depth than could be obtained normally by the action of wind blowing more or less horizontal with respect to the local ground surface.
In accordance with the present invention, enhanced cooling or forced refreezing of spray ice or forced freezing of impounded sea water can be accomplished by use of a large downward-facing fan that is moved over the freshly sprayed or flooded surface to decrease the heat transfer resistance between the ambient temperature and surface temperature. There are two important factors that work together to increase the freezing speed considerably. These two factors are that the heat transfer coefficient is much greater in stagnation flow, compared to parallel flow; and, in a related aspect, the blowing arrangement ensures that the cold far-field temperature is brought in closer proximity of the surface.
Virtually any technique for moving fan, or other source of downwardly directed frigid air, across a surface may be employed. By the present invention, it is the movement of large volumes of cold ambient temperature air downward against a layer of freshly prepared spray ice or impounded sea water which is important and for the purpose of more quickly and completely freezing or refreezing the surface material. The air stream produced by the fan can be controlled so that spray ice or impounded sea water may be cooled over a greater depth than is possible by natural cooling due to wind movement horizontally across the spray ice or impounded sea water surface. This more efficient cooling will lead to more complete freezing and refreezing and, thereby, production of a stronger structure in a shorter time.
In Arctic regions, it is common practice to employ wheeled and tracked vehicles in conjunction with ice island and other types of construction activities. Modification of these devices by addition of the ventilation fan is practical, feasible, and by means disclosed herein, beneficial in providing for more rapid and complete freezing and refreezing of spray ice and impounded sea water. Application of the methods disclosed herein will, therefore, significantly shorten the time normally required to fabricate an ice structure and, therefore, reduce construction costs. Furthermore, application of the disclosed methods will result in ice structures having greater inherent load-bearing capacity and resistance to shear, by virtue of more complete freezing, than could otherwise be reasonably expected by application of what is generally recognized to be standard and accepted ice structure construction practice.
An obvious implication of the forced refreezing method is its extension to ice construction involving primarily the preparation of offshore ice roads, camps, air fields, parking ramps and the like.
It is apparent from the foregoing brief description that the present invention offers many advantages over the prior art methodology. These and other advantages and other objects are made more clearly apparent from a consideration of the several forms in which the present invention may be practiced. Such forms are described and forms of the various apparatus which may be used in the practice of this invention are illustrated in the present specification. The forms described in detail are for the purpose of illustrating the general principles of the present invention; but it is to be understood that such detailed description is not to be taken in a limiting sense.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic view of one form of apparatus which may be used to practice the present invention;
FIG. 1a is a diagrammatic view, in section, of the device illustrated in FIG. 1;
FIG. 2 is a diagrammatic view of another form of apparatus which may be used in the practice of the present invention;
FIG. 2a is a diagrammatic view, in section, of the device illustrated in FIG. 2;
FIG. 3 is a diagrammatic view of yet another form of apparatus which may be used in the practice of this invention; and
FIG. 3a is a diagrammatic view, in section, of the device illustrated in FIG. 3.
DETAILED DESCRIPTION OF THE INVENTION
In accordance with the present invention, load-bearing ice structures may be fabricated from frozen sea water and in those geographic areas and at those times of the year in which the ambient air temperature is below about minus one degree C. The fabrication of ice structures, in accordance with the present invention, also contemplates the continued maintenance of a site in those regions amenable to construction of ice structures. Thus, for example, roads or aircraft runways and the like may be partially completed by conventional construction and completed or processed in accordance with the present invention.
There are two basic modes of practicing the improved ice construction methodology of the present invention. In one mode, a spraying technique, as described, may be used. In the other a berm is formed to impound sea water and thereafter the construction proceeds in accordance with this invention.
Ice construction applications involving the freezing of sea water sprays benefit from a reduction in the time required to refreeze partially melted spray ice. In similar fashion, more rapid freezing of impounded sea water would be desirable and beneficial. Accelerated rates of freezing of spray ice and impounded sea water can be obtained by directing a controlled column of frigid ambient air vertically downward against the surface to be frozen. The air temperature should be at least below about minus one degree C. in order to effect freezing of sea water.
As mentioned, in the use of spraying techniques, the spraying operation, in addition to providing for the formation of ice particles, by the freezing of water drops, results in the formation of a slush ice which is of a salinity greater than the normal salinity of sea water. The slush ice is, in effect, a residue having a salinity somewhat higher than that of the sea water initially frozen from the droplet spray. As noted, the refreezing of this slush ice is responsible for the development of strength in the formation spray formed ice structures. In the case of spay ice construction, it is this refreezing which adds to the time of construction and which is needed in order to develop the desired strength of the load-bearing ice structure.
By the present invention, an initial ice structure is formed. For the purposes of this invention, the initial ice structure is that initially formed at the start of the construction and which, in effect, forms the base upon which the final ice structure is constructed. Overall, the process is cyclical, involving spraying, freezing and refreezing, and spraying etc., a cycle that is repeated until the structure is completed.
By the present invention, the freezing and refreezing portion of the cycle is shortened and the nature of the frozen product, in terms of its load carrying qualities, is improved over prior practices. To effect this improvement, it is necessary to effect reasonably rapid freezing of the slush ice or impounded ice, in order to achieve a depth of frozen ice which enhances the loadcarrying ability of the finished ice structure.
By the present invention, this is accomplished by the formation of an initial ice structure, either by spraying or impounding procedures, followed by directing downwardly towards the surface of the initial ice structure a controlled column of frigid ambient air. Since the surface of the initial ice structure possesses sufficient integrity to support weight, vehicles may be used to transport equipment intended to generate a downwardly vertically directed column of air. Thus, the methodology involves traversing the initial ice structure while directing the column of air against the surface of the ice structure. in general the entire surface of the initial ice structure is traversed, although this may not be necessary for those portions intended not to be significant load-bearing regions of the completed ice structure.
After the first pass, additional sea water is sprayed or added to the impounded area and the process is repeated. In those instances in which the surface of the initial ice structure is such that it is undesirable to use ground vehicles, a helicopter may be used in which case the main rotor down wash forms the controlled column of air which is directed against the ice surface.
As an example of the type of vehicles which may be used, reference to the drawings, FIGS. 1 through 3, which illustrate typical land vehicles of the type used in the Arctic region. As illustrated in FIGS. 1 and 1a, a ventilation fan 10 and its associated speed control and electric power generator 12 are mounted on a wheeled platform 15 that is towed behind a wheeled primary power unit 20. The power unit 20 may, for example be a unit known commercially as a ROLL-E-GONE power unit.
The air rate is adjusted so as to disturb the spray ice surface with air penetration into the spray ice or, alternatively, into a layer of impounded sea water. Disruption and dispersion of spray ice is minimized by placement of a shroud 25 about the fan which also serves to channel the column of frigid air downwardly. Disrupted and refrozen spray ice may be converted to a smooth surface by passage of the rake 30 located at the end of the fan platform 15. In use, the vehicle traverses the initial ice structure while the fan blows a column of frigid air downwardly towards the surface. One pass is usually sufficient, depending upon the capacity of the fan and the rate of travel. If necessary a partial or added pass may be made, as needed. Thereafter, spraying is continued or additional sea water is added to the impounded area formed by the berm.
Alternatively, the fan conveyance of FIGS. 2 and 2a may be employed, in which cases, the various components, such as the fan 50 and the generator 52 are mounted on the bed 55 which is combined into a single power unit. The shroud 65 is located as illustrated, with the rake 66 mounted on the end of the bed. The unit illustrated in FIGS. 3 and 3a is similar to that of FIGS. 2 and 2a except that the vehicle is a tracked vehicle 75, as shown.
In use, a layer of spray ice of six (6) to twelve (12) inches thickness is formed. Sea water spraying would then cease for the period required to freeze the deposited material by passage of the fan. Sea water spraying or flooding would then resume and the cycle of spraying or flooding followed by forced refreezing would continue as necessary until an ice structure of desired size were built.
It will be apparent from the above detailed disclosure that various modifications may be made, based on the above detailed disclosure, and it is understood that such modifications as will be apparent to those skilled in the art are to be considered within the scope of the present invention as set forth in the appended claims. So, for example, the passage of a helicopter over an impounded body of sea water would be but another instance of the application of the present invention. Similarly, the passage of a hydrofoil or hovercraft, which is a vehicle that moves on a cushion of air, over a spray ice surface or a body of impounded sea water, can be seen to be but another embodiment of the forced refreezing method. | A method for accelerating construction of a load bearing ice island, formed by either sea water spraying or flooding techniques, of higher quality or in a shorter time or both than would otherwise be possible. The method involves forced refreezing of spray ice by application of a vertical stream of cold ambient air, as produced by a fan or other devices described, directly downward on the ice surface or by application of the downwardly directed air stream to an impounded mass of sea water. The specific application for the process is construction of improved load bearing structures as used in Arctic regions in support of offshore hydrocarbon exploration and production activities. | 24,461 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a welding auxiliary material for welding refractory metal parts of high-intensity electric light sources.
2. Description of the Prior Art
When manufacturing halogen lamps, the joints between the refractory metal parts such as tungsten or molybdenum are welded joints, as the reliability of the joints is an indispensable requirement.
Refractory metal parts of low-wattage halogen lamps with "standard", i.e. not long or extended life, are welded directly together, if no special requirement exists. This, however, does not ensure a satisfactory joint in every case. The Hungarian Patent No. 185.198 discloses a molybdenum lead-in foil for elimination of unsatisfactory features. The surface of the foil is provided with a thin electroplated rhenium layer. Such a lead-in foil has better weldability properties than the simple uncoated foil. A foil prepared in that way is useful in the manufacture of halogen lamps with low current loads and "standard" lives, for joining refractory metal parts and meets the requirements for reliable operation on that field, but not in the case of halogen lamps with extended or long lives and heavy current loads.
This is explained by the fact that only a low-thickness rhenium layer can be applied to the surface of the lead-in foil. This has the consequence that, during the welding operation, the lead-in wire is unable to get embedded into the thin rhenium layer applied to the lead-in foil and therefore, a small-surface weld will be produced. In case of high-wattage halogen lamps, the current flow - due to the high current density-generates a substantial amount of thermal load resulting in the earlier destruction of the joint and in shortened lamp life.
The functionability of halogen lamps with high current loads and lives of several thousand hours can only be insured if higher requirements for joining the refractory metal parts and for the bond produced in welding are met.
In some types of lamps with high current loads as well as long lives, a separate platinum welding auxiliary is placed between the basic metal foil and the current lead-in order to produce a welded joint of satisfactory quality.
In this case, platinum will melt during welding and form a molybdenum-platinum alloy phase with a portion of the molybdenum material of the foil. This adversely affects the strength at high temperatures of the molybdenum foil which can result in thickness decrease, cracks and tear in the foil.
Another disadvantage is that after melting at the temperature necessary for pinch-sealing the lamp liquid and/or vapour phase platinum can enter the inner space of the lamp where, on reaching the tungsten filament, a lower-melting platinum-tungsten alloy will be formed. This has the possible consequences of local filament fusing and arcing that result in early lamp failure.
It should also be considered a disadvantage that the melt creeps on the current lead-in during welding with the consequence that no gas-tight seal will be achieved in some cases.
A further disadvantage is that the so-called "brazed joint" will in lamp operation, caused by the local thermal load, get alloyed gradually into the basic metals during the time of operation. Caused by this "loss" of the initial bond, the cross-section available for current conduction will decrease and the local thermal load will be enchanced resulting in a further "loss" and a rapid deterioration of the joint. It is also a common practice to use a platinum coated welding auxiliary material for welding refractory metal parts together. This method suffers from the disadvantages described earlier in the discussion of platinum welding auxiliary material.
According to the U.S. Pat. No. 4,823,048, a joint is produced by spot-welding the inner current lead-in and the metal foil together and a welding auxiliary material foil is connected, also by means of welding, to this joint. The filler foil increases the surface area available for current conduction thereby reduces current density. One end of the metal foil is connected to the large-surface portion of the metal foil opposite to the inner current lead-in and its other end, to the inner current lead-in.
The joint according to U.S. Pat. No. 4,823,048 has the disadvantages of being complicated to produce and also the inability to solve the problems described earlier related to the cross-section reduction or tear of the current lead-in foil.
OBJECTS AND SUMMARY OF THE INVENTION
The object of the present invention is therefore to provide welding auxiliary material enabling to join the inner and outer current lead-in of high-wattage electric light sources with the current lead-in foil in a simple and rapid and reliable manner, without damage to the parts during welding and the subsequent pinch-sealing process.
Another object is to provide reliability for the joint even in the case of heavy current conduction properties over the time of operation.
Other objects and advantages of the present invention will become apparent from the description and drawings which will follow.
It has been found that a welding auxiliary material of unique structure and suitable thickness can be prepared by sintering refractory metal powder. Accordingly, the welding auxiliary material for producing welded joints between the refractory metal parts of high-wattage electric light sources is formed with a porous-structure surface layer sintered from a refractory metal powder having a melting point of above 2000° C.
The welding auxiliary material according to the invention can be further characterized by that the material of the refractory metal powder is molybdenum and/or rhenium.
In a preferred embodiment, the surface layer is sintered on a refractory metal substrate which substrate is a molybdenum foil.
In another embodiment, the surface layer pores are impregnated with and additive that promotes welding. In a preferred embodiment, ethanol or other alcohol derivative is used for the additive.
The welding auxiliary material has several favourable properties. Due to the porous-structure surface layer, the outer surface of the welding auxiliary material is rough including the side facing the molybdenum current lead-in foil.
During the welding operation, the relatively rough surface will make many point-like contacts with a high contact resistance and, caused by the intensive local heat generation, the welding auxiliary material will melt producing microweld spots and resulting in a large-surface welded zone.
Due to the intensive local heat generation, the time needed for welding can be shortened and this has the consequence that no recrystallization process will occur in the parts preventing the current lead-in parts from becoming brittle.
It should also be considered an advantage that the method of sintering, according to this invention forms a thicker surface layer and the current lead-ins will get embedded deeper into this thicker surface layer which increases the cross-section available for conduction. The increased cross-section results in improved current conduction properties and lower specific heat load and this leads to the prolongation of life.
It is also a significant advantage of the present invention that--due to the thicker surface layer--the material surrounding the weld neither will become overly thin nor will be distorted since the welding auxiliary material is thick enough to have satisfactory amount of material for producing the joint.
The strength properties at high temperatures of the rhenium-molybdenum and rhenium-tungsten alloys formed by welding when the rhenium-containing welding auxiliary material is used are more favourable than those of the component metals and these alloys melt high above the temperature used during the pinch-sealing process. Due to this fact, the undesired effects which are unavoidable when a platinium metal sheet is used, will not occur.
When the welding auxiliary material according to the invention is used, the alloy phase does not creep on the current lead-ins and does not melt during pinch-sealing. This results in a gas-tight seal that can be produced more safely than in the case of other known methods.
A further advantage of the welding auxiliary material according to the invention is that the pores can be filled with an additive promoting the welding process and, due to this, the welding auxiliary material is able by itself to provide a protective atmosphere during welding. This solution not only improves the quality of the welded joint, but also reduces the expenses for the welding operation by making unnecessary some machine accessories that have been indispensable so far.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following, a more detailed description of the invention will be given by means of examples illustrated by drawing figures. In the drawings:
FIG. 1 is a perspective view of a preferred embodiment of the welding auxiliary material according to the invention,
FIG. 2 is the cross-section of another preferred embodiment,
FIG. 3 is a view, partly in section, of the welded joint produced using the welding auxiliary material and
FIG. 4 is the sectional view taken along IV--IV of FIG. 3.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1, an embodiment of the welding auxiliary material is shown, the entire cross-section of which is prepared from molybdenum metal powder using sintering. The welding auxiliary material 1, also including its surface layer 1a has a porous structure and consists of molybdenum grains ground to grain sizes below 10 microns. Thickness "v" of the welding auxiliary material 1 is 50 microns in this example, but it may vary depending on the field of application.
In FIG. 2, the cross-section of an embodiment is seen in which the surface layer 1a of the welding auxiliary material 1 is sintered on the refractory, preferably molybdenum metal substrate 2 having a sheet thickness "s" of 20 microns. Use of the metal substrate 2 is recommended in order to facilitate the handling of the welding auxiliary material 1. Thickness "v" of the welding auxiliary material 1 is 60 microns in this embodiment from which one can calculate that the construction thickness "h" is preferable in respect of producing the welded joint, but the construction thickness "h" of the surface layer 1a may vary from 10 microns up to 50 microns.
The pores of the surface layer 1a of the welding auxiliary material 1 are filled with an additive 3 preferably consisting of ethanol, but other alcohol derivatives can also be used. The additive 3, evaporating by the heat generated during welding, forms a protective atmosphere further improving the quality of the weld.
In another embodiment, the surface layer 1a is prepared from the mixture of rhenium and molybdenum metal powders instead of molybdenum powder alone. The proportion of rhenium to molybdenum may range between rather different values as the properties of the joint produced are improved by a welding auxiliary material 1 with as low as 5 to 10% rhenium content.
To show an example, the preparation of the welding auxiliary material 1 is performed as follows. The molybdenum foil metal substrate 2 having a sheet thickness "s" of 20 microns is coated with a mixture of rhenium and molybdenum metal powders ground to 1 micron grain size and suspended in alcohol. The proportion of rhenium to molybdenum is 2:1 in the mixture. This is followed by the sintering process performed in hydrogen-flushed tungsten-tube furnace at 2200° C. for 5 minutes. After this, the welding auxiliary material 1 described above and having the surface layer 1a with porous structure is prepared.
FIGS. 3 and 4 show an example for the use of the welding auxiliary material 1. Current lead-in foil 8 and outer current lead-in wires 7 and 7' welded to it as well as inner current lead-in 6 are placed in pinch-sealed portion 5 of bulb 4. The welding auxiliary material 1 being between the current lead-in foil 8 and the inner current lead-in 6 as well as between the current lead-in wires 7 and 7' and the current lead-in foil 8 is found only in the environment of the welded spot. The current lead-in foil 8 is made of molybdenum and the material of the inner current lead-in 6 is tungsten or molybdenum known and commonly used in light source manufacture.
It is seen clearly in FIG. 4 how the inner current lead-in 6 is connected to the current lead-in foil 8 fixed in the pinch-sealed portion 5.
The surface layer la molten caused by the effect of heat during welding surrounds the inner current lead-in 6 over a large surface and, due to this, the joint provides better conditions for current conduction than the known solutions do.
The welding auxiliary material 1 can be successfully used for welding together the parts located in pinch-sealed portions of electric light sources. Due to its favourable properties such as the resistance to reactive environments, it can also be used for joining parts inside the bulb of mercury and metal halide lamps.
Although only preferred embodiments are specifically illustrated and described herein, it will be appreciated that many modifications and variations of the present invention are possible in light of the above teachings and within the purview of the appended claims without departing from the spirit and intended scope of the invention. | An improved welding auxiliary material for producing welded joints between refractory metal parts of high-wattage electric light sources is described. The characteristic feature of the invention is that the welding auxiliary material has a porous structure surface layer sintered from a refractory metal powder having a melting point of above 2000° C. | 13,807 |
FIELD OF INVENTION
[0001] Generally, embodiments of the invention relate to integrated electronics and integrated electronics systems. More specifically, embodiments of the invention relate to a technique and corresponding infrastructure to maintain order of events corresponding to operations for caching agents operating according to a caching protocol where the caching agents are separated from the protocol agents.
BACKGROUND
[0002] Computer systems and processor architectures, in particular, can use various types communication networks and protocols to exchange information between agents, such as electronic devices, within those systems and architectures. Multiple processing elements (“processing cores”) in a microprocessor, for example, use caching agents to store, retrieve, and exchange data between the various cores of the microprocessor. Likewise, computer systems in which single or multiple core microprocessors are interconnected may use caching agents to store, retrieve and exchange data between the microprocessors or other agents.
[0003] In electronic networks, cached data is managed and exchanged according to certain rules, or “protocol,” such that coherency is maintained among the various caches and the devices, such as processing cores, that use the cached data. Caching activity across these devices directly serviced by the caches, such as lookup operations, store operations, invalidation operations, and data transfer operations, can be managed by logic or software routine (collectively or individually referred to as a “cache agent”), such that cache coherency is maintained among the various caches and cache agents. Caching activity within or outside of a microprocessor, such as snoop resolution, write-backs, fills, requests, and conflict resolution, can be managed by logic or software routine (collectively or individually referred to as a “protocol agent”), such that coherency is maintained among the various cache agents and processing cores within the microprocessor and among agents external to the microprocessor. In some prior art multi-core or single-core processors, for example, the caching agent is coupled to a specific coherence protocol agent, which may be physically integrated within the caching agent to which it corresponds. This means that the same circuit and/or software routine may be responsible for implementing cache operations, such as requests, dirty block replacement, fills, reads, etc., as the protocol for managing these operations.
[0004] FIG. 1 illustrates a prior art microprocessor having a number of caching agents, each having circuitry to implement the caching protocol used among the caching agents of the microprocessor. In the prior art processor of FIG. 1 , each caching agent is responsible for implementing and keeping track of the cache protocol as applied to itself. That is, each cache agent is coupled to a protocol agent, such that the same unit is responsible for both cache operations and the coherence protocol. Unfortunately, this “decentralized” caching protocol architecture requires redundant use of protocol logic and/or software to maintain the caching protocol among all caching agents within the processor or computer system to which the protocol corresponds. In the case of the protocol being implemented using complementary metal-oxide-semiconductor (CMOS) logic devices, this can result in substantial power consumption by the processor or system, especially in multi-core processors having a number of caching agents.
[0005] Furthermore, the prior art caching architecture of FIG. 1 may be somewhat bandwidth limited in the amount of caching traffic supported among the caching agents, as each caching agent has to share the same bus, cache agent ports, and cache agent queuing structure that facilitate communication among the various caching agents.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] Claimed subject matter is particularly and distinctly pointed out in the concluding portion of the specification. The claimed subject matter, however, both as to organization and method of operation, together with objects, features, and advantages thereof, may best be understood by reference to the following detailed description when read with the accompanying drawings in which:
[0007] FIG. 1 illustrates a prior art caching architecture used within a microprocessor or computer system.
[0008] FIG. 2 illustrates a caching architecture according to one embodiment of the invention.
[0009] FIG. 3 illustrates a caching architecture including routing circuits according to one embodiment of the invention.
[0010] FIG. 4 illustrates a block diagram of one embodiment of message ordering logic to accommodate the various message types while ensuring proper ordering.
[0011] FIG. 5 illustrates a computer system having a shared bus architecture, in which one embodiment of the invention may be used.
[0012] FIG. 6 illustrates a computer system having a point-to-point bus architecture, in which one embodiment of the invention may be used.
DETAILED DESCRIPTION
[0013] Embodiments of the invention disclosed herein describe a caching architecture that may be used in an electronic device, such as a single core or multiple core microprocessor, or an electronics system, such a shared bus computer system or a point-to-point (P2P) bus computer system. More particularly, one embodiment of the invention includes a caching architecture, in which the caching protocol is more centralized and decoupled from the caching agents to which the protocol corresponds than in some prior art caching architectures.
[0014] With cache agents and protocol agents being detached, a pre-coherence channel is used to ensure that the protocol agent is kept current with the coherence information from the cache agents. In one embodiment, the pre-coherence channel includes an on-chip, or local, interconnection network. In this manner, cache events may have their order maintained and the protocol agents have a view of the coherence of the cache(s) in the system.
[0015] In one embodiment, a cache agent can communicate with a protocol agent using two signals that operate in part of the pre-coherence channel: one signal (“AD”) to communicate addressed caching operations, such as data and/or cache ownership requests, data write-back operations, and snoop responses with data for cache-to-cache transfers, from a cache agent, and one signal (“AK”) to communicate non-address responses, such as cache fill acknowledgements and non-data snoop responses, such as a cache “hit” or “miss” indication. Furthermore, in at least one embodiment, each signal may transmit information in opposite directions within the same clock cycle. For example, AK may transmit a first operation, such as a request operation, to a first protocol agent during a first clock cycle in a first direction while transmitting a second operation, such as a write-back operation, to the first or a second protocol agent in the opposite direction during the same clock signal.
[0016] The concurrent bidirectional characteristics of the signals, AD and AK, can be conceptualized by two sets of cache agents, routing circuits, and a protocol agent interconnected by two signals, or “rings,” transmitting an AK and AD signal, respectively, in one direction. FIG. 2 , for example, illustrates one embodiment of a caching architecture, in which the two signals, AD and AK, are conceptualized as four rings, two of which are capable of transmitting information in a clockwise direction and two of which are capable of transmitting information in a counter clockwise direction. In particular, the caching architecture 200 of FIG. 2 depicts a first set of caching agents 201 , 203 , 205 , and 207 that correspond to a first caching protocol agent (“protocol agent”) 209 and a second set of caching agents 202 , 204 , 206 , and 208 that correspond to a second protocol agent 210 . Note that in alternative embodiments, only single separate rings are used for the AK and AD signals. In yet another embodiment, more than two rings are used for each of the AK and AD signals.
[0017] Each cache agent of the first set can communicate cache operations such as loads and stores to processing cores (not shown in FIG. 2 ), and data requests, data write-back operations, cache fill acknowledgements, and snoop response transactions, to the first protocol agent. Likewise, each cache agent of the second set communicates these non-data cache transactions to the second protocol agent. The cache agents may communicate to the protocol agents, in one embodiment, through a series of router circuit (not shown in FIG. 2 ).
[0018] The first and second protocol agents are responsible for arbitrating between the various operations from their respective cache agents such that the operations are managed and completed in a manner consistent with the caching protocol of the caching architecture.
[0019] In one embodiment, each cache agent has access to four communication channels (depicted by rings in FIG. 2 ) 211 , 212 , 213 , 214 , upon which caching transactions may be communicated. Each cache agent may communicate cache transactions on any of the four rings illustrated in FIG. 2 . In other embodiments, each cache agent may be restricted to a particular ring or group of rings upon which caching transactions may be communicated to/from the cache agent. The cache data that results from the transactions communicated on the rings of FIG. 2 may be communicated among the cache agents on other communication channels (e.g., data bus) not depicted in FIG. 2 . Alternatively, in some embodiments the cache data may be communicated on the rings depicted in FIG. 2 . Moreover, in other embodiments, each network in FIG. 2 may be configured in other topologies, such as tree topology or a chain.
[0020] In the embodiment illustrated in FIG. 2 , caching transactions, such as data and/or cache ownership requests, data write-back operations, and snoop responses with data are sent on rings 212 and 214 (“address” rings) and transactions, such as cache fill acknowledgements and non-data snoop responses, such as a cache “hit” or “miss” indication, are transmitted on rings 211 and 213 (“non-address” rings). In other embodiments, the above or other transactional information may be transmitted on other combinations of the rings 211 - 214 . The particular ring assignment for the various cache transactions discussed above and illustrated in FIG. 2 are only one example of the transactions and ring assignments that may be used in embodiments of the invention.
[0021] As each set of cache agents communicates information between each other via the protocol agents, an ordering of the information entering the protocol agent can be maintained, in at least one embodiment, such that the correct information will allow correct coherence protocol transitions in the protocol agent at the correct time. In one embodiment, the ordering of information within the networks is maintained by each protocol agent. More specifically, in one embodiment, each protocol agent maintains the correct ordering of the various caching operations being performed by temporarily storing the operations as they arrive within each protocol agent and retrieving them in the order in which they arrived in order to produce correct coherence protocol transitions in the protocol agent.
[0022] In one embodiment, each protocol agent contains one or more buffers that may be used to store data, commands, or addresses originating from one of the cache agents, which can then be retrieved from the buffers in the proper order to be delivered to a particular cache agent. In the embodiment illustrated in FIG. 2 , each protocol agent includes, or otherwise has associated therewith, two first-in-first-out (FIFO) buffers 216 , 217 , 218 , 219 that are each coupled to two of the four rings of FIG. 2 . Each pair of rings illustrated can communicate information in a particular direction. For example, rings 211 and 212 can communicate information in a clockwise (CW) direction, whereas rings 213 and 214 can communicate information in a counter-clockwise (CCW) direction. In an alternate embodiment, only a single FIFO is used and only two of the four rings are used.
[0023] FIG. 3 is a diagram illustrating the ring structure of FIG. 2 in conjunction with various routing circuits, which route data to their intended recipient from each of the cache agents. In particular, FIG. 3 illustrates a number of cache agents, identified by the letter “C”, in a ring configuration of two networks, each comprising signals AD and AK to interconnect a cache agent with a protocol agent, identified by the letter “S”. A routing circuit, identified by the letter “R”, is associated with each cache agent to either route information contained within signals, AD and AK, to the next cache agent within a network (if the next agent in the network is not a protocol agent) or to a protocol agent (if the next agent within the network is a protocol agent).
[0024] Two of the routing circuits 310 and 315 couple the rings of the networks in FIG. 3 to the protocol agents, whereas other routing agents connect the rings to other cache agents and other ring networks. In one embodiment, a cache agent 307 may send a signal intended for one of the protocol agents on ring 301 in a clockwise direction. The routing agents between cache agent 307 and the intended protocol agent, moving in a clockwise direction around the ring, propagates the information contained within the signal between them until the signal reaches the routing circuit, 310 or 315 , which would route the signal to the intended protocol agent. For example, the signal described above would be retrieved by protocol agent 307 and the information within would be stored in the appropriate FIFO.
[0025] After information is stored within the FIFOs of a particular protocol agent, the protocol agent may process the cache events sent by the cache agent in accordance to the coherence protocol by retrieving, or “popping,” the information off of the FIFO in the order in which it was stored.
[0000] Ordering Rules
[0026] As discussed above, because the cache agents (e.g., cache controllers) are separate from the protocol agent, the coherence ordering point is not at the same location, particularly since there is a non-one-to-one mapping between cache controllers and protocol engines with a variable latency Chip Multi Processor (CMP) network in between.
[0027] More specifically, a cache controller performs cache actions, such as requests, writebacks, snoops, and fills in an internal order, and when applied in a sequence to a single block in the cache, results in the data and state of the block to be updated in the order according to the specific sequence. This ordered sequence of cache events is important to correctly implement the coherence protocol. For instance, in one embodiment, the communication of correct cache ordering allows snoop responses and new requests to be seen in the correct order by the detached protocol agent, giving it the visibility into the internal ordering at the cache controller for these events, thereby ensuring that a snoop doesn't incorrectly get reordered behind a request and become blocked. The cache ordering point is where cache events, such as snoops, request, writebacks, and fills are ordered with respect to one another. The coherence ordering point is where coherence decisions are made from events specifically necessary to implement the protocol state transitions. These events include the cache events set forth herein, which are brought into the protocol agent in the correct cache event ordering via the pre-coherence channel, along with external coherence events, which reflect the communication of the coherence view from other protocol agents in the system.
[0028] In one embodiment, the cache ordering point is made to appear as if it's located inside the protocol agent, which is located in the system interface instead of the cache controller. To do that, information contained in the cache agent's ordering point is shifted into the coherence ordering point via the pre-coherence channel.
[0029] In one embodiment, the pre-coherence channel gives a protocol agent a minimal view into the internal ordering at the cache agents, allowing the protocol agent to function in a detached way without violating coherence rules in the coherence protocol. In one embodiment, it recognizes what type of ordered cache events are important and thus need to be communicated in the pre-coherence channel to the protocol agent In one embodiment, the pre-coherence channel consists of an ordered mechanism to transport cache events from the cache agent into the protocol agent, and includes recovery and ignore mechanisms to allow a consistent coherence view of the system. The pre-coherence channel also includes a mechanism where resource dependencies are resolved by blocking the pre-coherence channel or moving the blockage to another FIFO to unblock the pre-coherence channel.
[0030] The use of pre-coherence channel ordering enables the cache agents to be detached from protocol engines. This provides a number of advantages such as, for example, the following advantages. First, it allows each protocol to be optimized for their own intended purposes (local protocol optimized for cache transfer performance, and off-chip protocol to support the complex conflict and coherence completion rules). Second, it modularizes the overall chip design. Third, it allows more effective resource sharing between the local cache agents in a multiple cache agent design. Fourth, the local protocol hides on-chip coherence operations from off-chip protocol, so off-chip bandwidth is saved.
[0031] In one embodiment, the pre-coherence channel is implemented as a virtual ordered route by which cache specific information is communicated from the cache agent into the specific logic that maintains the system interface's coherence ordering point, which is a request inflight table referred to herein as the missing address file (MAF), located in the protocol agent. Physically, this virtual route is implemented as the CMP network, and egress and ingress buffering on either side of the network within the cache and protocol agents respectively leading from the cache control logic to the MAF. The CMP network is the link and physical layers of the an on-chip communication consisting of the CMP address, acknowledgement, and data networks, between cache agents, processors, and protocol agents, shown as the collective of the bus network and its routing components in FIG. 3 .
[0032] In one embodiment, the pre-coherence channel ordering is relaxed to allow a certain degree of out-of-ordering to lessen the restrictions on the CMP network in cases where reordering effects can either be (1) recovered, or (2) ignored because they do not cause the cache and protocol agent's states to diverge.
[0033] Since the protocol agent is apart from the cache agent, cache ordering needs to be communicated into the protocol agent. A set of rules is set forth herein by which a cache agent communicates the cache ordering into the protocol agent across a CMP network to a protocol agent.
[0034] In one embodiment, the following message types communicate the ordering point from the cache controller into the system interface: requests, writebacks, data (fill) acknowledgements, and snoop responses. These messages come into the protocol agent as a single input stream of events. From the dependency point of view, in one embodiment, they are classified into three types: simple flow dependency, cyclic resource dependency, and acyclic resource dependency.
[0035] For a simple flow control dependency, data acknowledgement and snoop responses do not require allocation of a resource in order to be consumed. In one embodiment, they both could potentially create home channel messages, which are sunk in preallocated buffers in the home node of the system, thus, not requiring additional dependency aside from message flow control. (The home node may be part of the memory controller in a system responsible for connecting each of the processors in the system to the memory controller, and these transactions are used to implement a coherence protocol in which these processors and the home node coupled to the memory controller jointly participate.)
[0036] For a cyclic resource dependency, requests depend on the allocation of a resource. In one embodiment, because resource sharing (as opposed to resource division) is allowed, a request may not have a free MAF entry to allocate. In order to make room for allocation, another entry needs to retire, and for that to occur, snoops need to make forward progress. If a request is blocking the input event stream, then snoop responses behind the request are prevented from making forward progress. As long as snoop responses are blocked, the protocol engine cannot complete requests, and request entries in the MAF will not retire, which is a deadlock condition. Request allocation depends on request forward progress, which depends on snoop forward progress, which depends on the event stream making forward progress, which is blocked by the request.
[0037] For acyclic resource dependency, writeback transactions also have a resource dependency on allocation into the MAF. While blocking on a MAF entry to become available, the input stream from the cache agent is also blocked. However, this is a benign resource dependency because writeback forward progress is not dependent on the any messages behind it, namely, a snoop response message following it from the cache agent. As long as there is a reserved writeback allocation path into the MAF, writebacks can achieve still forward progress even by blocking the input event stream.
[0038] FIG. 4 is a block diagram of one embodiment of message ordering logic to accommodate the various message types while ensuring the proper ordering of the cache coherency events. In one embodiment, this logic is in the protocol agent. The ordering logic uses two separate FIFOs and includes the MAF.
[0039] Referring to FIG. 4 , an incoming stream of events is impact into ingress queue (e.g., FIFO) 403 . Such events are received from the pre-coherence channel ordering interface (e.g., rings) between the one or more protocol agents and one or more caches (e.g., cache agent 401 ) in the sets of caches. These events are received in the form of messages that include requests, writebacks, data acknowledgements, snoop no data messages, and snoop data messages.
[0040] The head of ingress FIFO 403 is coupled to one input of arbiter 405 . In one embodiment, only the head of ingress FIFO 403 is allowed to arbitrate for input into MAF 406 . In one embodiment, non-request events are allowed to block at the head of ingress FIFO 403 while waiting for resources, but if a request is at the head of ingress FIFO 403 and blocked, it is moved into spill FIFO 404 instead, thereby allowing the stream of events following it in ingress FIFO 404 to proceed to avoid deadlock. In one embodiment, the move is done by obtaining an issue slot by doing a poison issue when not all the resources are available. The poison issue is one which is interpreted as a nop elsewhere, but enables allocation into spill FIFO 404 .
[0041] In one embodiment, spill FIFO 404 is preallocated with the total number of requests from all cache agents from which the protocol agent can receive. In one embodiment, unallocated requests have one way pre-coherence ordering with respect to the other messages. Thus, an unallocated request cannot shift forward in the pre-coherence channel but is allowed to move backwards. In other words, the protocol agent pretends the cache agent request was sent later than it was with respect to snoops following it. Additionally requests are out-of-order with respect to each other. Subsequently, arbiter 405 arbitrates between the outputs of ingress FIFO 403 and spill FIFO 404 .
[0042] Thus, from the dependency point of view, requirements are made on the reordering of requests in comparison to all other events in the pre-coherence channel ordering. In these reordered cases, reordering is done on the pre-coherence channel where it would not have been allowed in at the system interface. These happen in cases where either the protocol agent is able to recover, or the reordered perception of events do not force the cache and coherence agents to diverge. The following matrix describes what may or may not be allowed to reorder in one embodiment:
X followed Snoop Data Snoop No by Y Request Writeback Hit Data Data Ack. Request Unordered(1) Ordered(2) Ordered(2) Unordered(7) Unordered(1) Writeback Must allow Ordered(2) Unordered(6) Unordered(8) Unordered(5) reorder(3) Snoop Data Must allow Ordered(2) Unordered(6) Unordered(8) Unordered(5) Hit reorder(3) Snoop No Must allow Ordered(2) Ordered(2) Ordered(2) Unordered(5) Data reorder(3) Data Ack. Impossible Impossible Ordered(4) Ordered(4) Impossible
[0043] (1) Multiple requests to the same address can be inflight from the cache agent, or a new request could come from the cache agent before the old one has been retired. In one embodiment, a CAM is implemented in the protocol agent to serialize the requests and guarantee there's only one outstanding request to an address in the system. This is provided so that the rejected second requires will be able to fairly arbitrate the next time.
[0044] (2) A request, writeback, or snoop response need to be ordered behind prior writebacks and snoop responses. In one embodiment, out-of-order events between cache and protocol agents for these event sequences cannot be changed to make a coherent series of events through pre-coherence channel architecture efforts, so they are disallowed.
[0045] (3) A snoop response or writeback following a matching request are required to be able to pass ahead of a blocked request to avoid deadlock.
[0046] (4) In one embodiment, a data acknowledgment could trigger the coherence protocol to enter a conflict phase, if earlier snoop responses have resulted in conflict against the same transaction receiving the data acknowledgements. Therefore, the correct ordering of snoop responses versus data acknowledgement is communicated on the pre-coherence channel to ensure conflicts are properly detected to allow entrance into conflict phase.
[0047] (5) In one embodiment of the coherence protocol, cache replacements and snoops on the returned data are allowed to occur in the cache agent prior to the coherence agent completing the transaction. These are allowed to merge into the active transaction and activate once the transaction is complete. Thus, the pre-coherence channel ordering allows these to be reordered ahead of the data acknowledgement, so that they merge into the transaction before it is potentially completed by the data acknowledgement. A recovery method is used to buffer early extracted data from writebacks and snoop data hits and unbuffer and covert to writebacks after completion of the said request.
[0048] (6) These cases are only for fetch type requests, for which the peer agent is only obligated to give a recent (non-infinitely-stale) version of the data. A snoop response can be unordered with a writeback or another snoop response to return an almost current data.
[0049] (7) A snoop miss passed by a request is registered as a conflict, which is an ignored side-effect.
[0050] (8) These could only happen in the following sequence: snoop miss→data ack.→writeback or snoop hit. In one embodiment, the fill operation occurs in the middle. One pre-coherence channel implementation relies on the MAF to buffer the writeback or snoop hit into the inflight request waiting for the data acknowledge, and then recovering through unbuffer and conversion to writeback.
[0051] The ordering requirements may be hardened in an implementation to make unordered relations ordered, but the table above defines the loosest relations between the messages that must travel on the CMP network into the coherence point in MAF 406 . Additionally, the request dependency requirements are satisfied in all parts of the network to avoid request deadlock.
[0052] In one embodiment, ingress FIFO 403 and spill FIFO 404 in the system interface could be part of the CMP network. All requests, writebacks, snoop responses, and data acknowledgements are explicitly made ordered in the FIFO, even though the pre-coherence channel does not require all of them to be ordered. Request dependency is fixed through spill FIFO 404 , which then allows requests to be unordered amongst requests to take advantage of rule 1 .
[0053] In one embodiment, the interconnect is a network of rings optimized for cache transfer between cores and caches. In one embodiment, there are three different types of ring networks to facilitate this: address, no-address, and data. In one embodiment, every message is one phit in length and the three ring networks exist to balance the message load between the rings. For instance, a read request on address is balanced by a cache response on data. Each of the ring networks is arbitrated separately. A ring guarantees point-to-point ordering, but ordering across different rings can be skewed, so keeping ordering across ring networks means ordered injection into the ring networks from a source.
[0054] To benefit most from the out-of-orderness allowed by the pre-coherence channel on this rings-based architecture, messages are split across address and no-address networks in the following way. Requests, writebacks, and snoop data hits are placed on the address network, and snoop no data and data acknowledgements are placed on the no-address network. Messages on each network are ordered between themselves. Two rings allow bandwidth to be doubled. In one embodiment, address ring injection does not need to be ordered with no-address ring injection, but the reverse requires order. That is, an address can pass no-address but not vice-versa.
[0055] Once into the protocol agent, all messages are piled into ingress FIFO 403 in the order they're received, which is the order the cache agent intends. No further reordering of messages occur in ingress FIFO 403 as they are pulled out and sent to be issued into MAF 406 in order under control of arbiter 405 . The out-of-orderness introduced on the ring network, but sill complying to the pre-coherence channel ordering, is reflected in ingress FIFO 403 , along with request out-of-orderness, which is introduced local to the system interface at the FIFO 404 , through arbiter 405 across the FIFOs into MAF 406 . The sum of out-of-orderness seen at MAF 406 is either corrected with special effort in the protocol agent such as rules 5 and 8 , or rationalized away to not affect the overall picture of the coherence protocol as in rules 1 , 3 , 6 , and 7 , in one embodiment of an implementation of a coherence protocol at MAF 406 . From that point on, messages travel on the coherence channel on or off-chip between protocol agents in the system.
[0056] FIG. 5 illustrates a front-side-bus (FSB) computer system in which one embodiment of the invention may be used. A processor 505 accesses data from a level one (L1) cache memory 510 and main memory 515 . In other embodiments, the cache memory may be a level two (L2) cache or other memory within a computer system memory hierarchy. Furthermore, in some embodiments, the computer system of FIG. 5 may contain both a L1 cache and an L2 cache.
[0057] Illustrated within the processor of FIG. 5 is one embodiment 506 . The processor may have any number of processing cores. Other embodiments, however, may be implemented within other devices within the system, such as a separate bus agent, or distributed throughout the system in hardware, software, or some combination thereof.
[0058] The main memory may be implemented in various memory sources, such as dynamic random-access memory (DRAM), a hard disk drive (HDD) 520 , or a memory source located remotely from the computer system via network interface 530 containing various storage devices and technologies. The cache memory may be located either within the processor or in close proximity to the processor, such as on the processor's local bus 507 .
[0059] Furthermore, the cache memory may contain relatively fast memory cells, such as a six-transistor (6T) cell, or other memory cell of approximately equal or faster access speed. The computer system of FIG. 5 may be a point-to-point (PtP) network of bus agents, such as microprocessors, that communicate via bus signals dedicated to each agent on the PtP network. Within, or at least associated with, each bus agent may be at least one embodiment of invention 506 , Alternatively, an embodiment of the invention may be located or associated with only one of the bus agents of FIG. 5 , or in fewer than all of the bus agents of FIG. 5 .
[0060] FIG. 6 illustrates a computer system that is arranged in a point-to-point (PtP) configuration. In particular, FIG. 6 shows a system where processors, memory, and input/output devices are interconnected by a number of point-to-point interfaces.
[0061] The system of FIG. 6 may also include several processors, of which only two, processors 670 and 680 are shown for clarity. Processors 670 and 680 may each include a local memory controller hub (MCH) 672 and 682 to connect with memory 22 , 24 . Processors 670 and 680 may exchange data via a point-to-point (PtP) interface 650 using PtP interface circuits 678 and 688 . Processors 670 and 680 may each exchange data with a chipset 690 via individual PtP interfaces 652 and 654 using point to point interface circuits 676 , 694 , 686 and 698 . Chipset 690 may also exchange data with a high-performance graphics circuit 638 via a high-performance graphics interface 639 . Embodiments of the invention may be located within any processor having any number of processing cores, or within each of the PtP bus agents of FIG. 6 .
[0062] Other embodiments of the invention, however, may exist in other circuits, logic units, or devices within the system of FIG. 6 . Furthermore, other embodiments of the invention may be distributed throughout several circuits, logic units, or devices illustrated in FIG. 6 .
[0063] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the claimed subject matter. However, it will be understood by those skilled in the art that the claimed subject matter may be practiced without these specific details. In other instances, well-known methods, procedures, components and circuits have not been described in detail so as not to obscure the claimed subject matter.
[0064] Reference in the specification to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the invention. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
[0065] In the foregoing specification, the invention has been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes can be made thereto without departing from the broader spirit and scope of the invention. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense. | A cache architecture to increase communication throughput and reduce stalls due to coherence protocol dependencies. More particularly, embodiments of the invention include multiple cache agents that each communication with the same protocol agent. In one embodiment, a pre-coherence channel couples the cache agents to the protocol agent to enable the protocol agent to receive events corresponding to cache operations from the cache agents to maintain ordering with respect to the cache operation events. | 37,097 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an apparatus for setting a liner in a well casing.
2. Description of the Related Art Including Information Disclosed Under 37 CFR 1.97 & 1.98
During the construction of oil and gas wells a wellbore is drilled in the ground. After a certain depth is reached drilling is halted and a well casing lowered down the wellbore and cemented in place. Drilling is then recommenced until the wellbore reaches the next predetermined depth. At this stage drilling is halted and a liner lowered down the well casing. The liner is suspended from the well casing by a device known as a liner hanger which acts between the liner and the well casing.
The liner hanger can be set mechanically or hydraulically. U.S. Pat. No. 3,291,220 shows an apparatus for setting a liner in a well casing, which apparatus comprises a liner hanger and a running tool. The running tool is provided with a valve seat obstruction of which will, in use, allow fluid pressure to be developed to set the liner hanger in the well casing. Once the liner hanger has been set the running tool is rotated anti clockwise to unscrew the running tool from the liner hanger. The running tool is then recovered.
BRIEF SUMMARY OF THE INVENTION
The present invention is characterised in that after the liner hanger has been set the application of further pressure will displace the valve seat to enable the running tool to be released and to allow fluid flow through the running tool.
Preferably, the liner hanger comprises a plurality of slips which are mounted on a ring which is restrained against motion by a shear member.
Advantageously, the liner hanger is provided with a packer and a member which, in use, applies pressure to the packer to deform it to occupy the space between said liner hanger and the well casing.
Preferably, the apparatus includes a plurality of slips, at least one of which is attached to the member by a shear member, the arrangement being such that when pressure is applied to the member via the slips the packer deforms to occupy the space between the liner hanger and the well casing, and subsequently the shear member fails so that the slips move into a position between the member and the well casing to retain the packer in its deformed position.
Advantageously, the slips form part of a polished bore receptacle.
Preferably, the running tool comprises a liner support unit which comprises a body, a unit which extends outwardly from the body and engages one of the liner and the liner hanger, and wherein the valve seat is disposed in the liner support unit and is releasably attached thereto by a shear member.
Advantageously, the apparatus includes at least one member which acts between the valve seat and the unit to maintain the unit in the extended position.
Preferably, the liner support unit comprises the body, a support which is fast with or integral with the body, and a ring which is slidably mounted on the body, rests on the support, and accommodates the unit, the arrangement being such that when the unit is in its extended position the body and the support can be moved relative to the ring and the unit accommodated thereby to a secondary release position in which the unit can move radially inwardly.
Advantageously, the body is provided with a recess to accommodate the unit when the body is in the secondary release position.
Preferably, the running tool is provided with a lug which rests on the liner hanger, and the liner hanger is provided with a slot which, when the lug is moved into alignment with the slot allows the running tool to be moved relative to the liner hanger and the liner support unit to be moved to its secondary release position.
Normally the liner is provided with both a liner hanger and a polished bore receptacle which extends upwardly from the liner hanger and is fitted with a junk bonnet which acts between the polished bore receptacle and the running tool to inhibit debris, for example cement, coming into contact with the many parts of the running tool whose operation could be inhibited or prevented by the ingress of debris.
Previously, after the liner has been set and cemented in position the final step has been to raise the running tool to an extent such that the junk basket is removed from the top of the polished bore receptacle. At this stage spring loaded lugs move outwardly from part of the running tool so that when the running tool is subsequently lowered the lugs bear on the polished bore receptacle which actuates the packer between the liner and the well casing. During this time debris is free to enter the tool and the polished bore receptacle which is undesirable both because of the prolonged exposure of the running tool to debris and the fact that debris can accumulate in the details of the liner hanger and polished bore receptacle impairing re-entry of the running tool should this be required.
According to another aspect of the present invention there is provided an apparatus for setting a liner in a well casing, which apparatus comprises a liner, a liner hanger, a polished bore receptacle, a packer which can be actuated by applying downward pressure to said polished bore receptacle, a running tool, and a junk bonnet which extends between said polished bore receptacle and said running tool and inhibits the ingress of debris into said polished bore receptacle, characterised in that said junk bonnet and said running tool are provided with means which, when said running tool is raised sufficiently, without removing said junk bonnet from said polished bore receptacle, co-operate so that if said running tool is subsequently lowered downward force applied to said running tool will be applied to said polished bore receptacle to set said packer.
Preferably, said means comprises a lip which extends radially outwardly from said running tool, and a hook which is biased radially inwardly from said junk bonnet.
Advantageously, said apparatus includes a ring which is disposed to restrict radial inward movement of said hook but which can be displaced by said lip to allow such movement.
Preferably, the junk bonnet comprises a unit which extends outwardly therefrom and engages the polished bore receptacle to inhibit separation thereof, and the unit is maintained in the extended position by a ring which is displaceable to enable said unit to move out of engagement with the polished bore receptacle.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
For a better understanding of the present invention reference will now be made, by way of example, to the accompanying drawings, in which:
FIGS. 1A, 1B and 1C together show a side view, partly in cross-section, of an apparatus in accordance with the present invention in use; and
FIG. 2 is a section taken on line II--II of FIG. 1 with parts omitted for clarity.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIGS. 1A, 1B and 1C of the drawings there is shown a liner 1 which is suspended within a well casing 2 by a running tool 100 which is attached to the bottom of a drill string (not shown).
The top of the liner 1 is attached to a liner hanger which is generally identified by reference LH. A polished bore receptacle 22 extends upwardly from the top of the liner hanger (LH).
The running tool 100 comprises an upper tubular member 3 and a lower tubular member 17 which are connected by a liner support unit (LSU) which is provided with a plurality of teeth units 16 which extend radially outwardly into grooves in the liner hanger LH and releasably connect the liner hanger LH to the running tool 100.
The teeth units 16 are maintained in position by dogs 15 which are themselves maintained in position by dog keepers 13 and 14 which are in turn maintained in position by a valve seat 5 which is held in the liner support unit LSU by a shear pin 12. The liner support unit LSU comprises a body 26 having a support 25 fast thereon. Ring 29 which accommodates the teeth units 16 is a push fit on the body 26.
In operation the liner 1 is lowered on the running tool 100. The weight of the liner 1 is supported by the liner hanger (LH) which bears on the teeth units 16 which are supported by the support 25 fast with the body 26. During this operation it is not uncommon for the liner 1 to become blocked by an obstruction. A common method of removing such obstructions is to pump fluid, typically drilling fluid, down through the liner 1 until the obstruction is removed whereafter the liner 1 can be further lowered.
When the liner 1 reaches the required position a ball 4 is released into the drill string. The ball 4 passes through the drill string and the upper tubular member 3 of the running tool 100 and comes to rest on the valve seat 5.
Fluid is then pumped down the drill string. Since the passage of fluid is blocked by the ball 4 the pressure is transmitted through holes 7 and 8 and acts on ring 9 which is restrained by shear pin 6.
When the pressure of the fluid reaches about 103 bar (1500 psi) the shear pin 6 fails which enables ring 9 to move upwardly. The ring 9 is provided with a plurality of separate and distinct slips 10 which, as the ring 9 moves upwardly, are forced outwardly by the tapered surface on a ring 11 until they engage the well casing 2.
Once the slips 10 have moved to their outermost position the fluid pressure is again increased until at about 172 bar (2500 psi) the shear pin 12 fails. The ball 4 and valve seat 5 travel down the lower tubular member 17 until they land on the floor thereof (not shown) below port 18. As the valve seat 5 moves downwardly the dog keepers 13 and 14 are no longer restrained nor are the dogs 15 or the teeth units 16.
Accordingly, when an upward force is applied to the running tool 100 the teeth units 16 should (if they have not already done so) move radially inwardly to allow the running tool 100 to be raised.
It will be noted that the release of the valve seat 5 permits separation of the running tool 100 from the liner 1. Furthermore, fluid flow through the running tool 100 is now re-enabled with the fluid leaving the running tool 100 via outlets including outlet 18 disposed along the length of the lower tubular member 17.
Should the liner 1 fail to separate from the running tool 100 in the manner described, for example by failure of the shear pin 12 to fracture or the valve seat 5 jamming, the running tool 100 includes a secondary release mechanism which is generally identified by reference SRM.
The secondary release mechanism (SRM) comprises three lugs 24 which project radially from a boss fast with the upper tubular member 3 of the running tool 100. In its normal position the lugs 24 overlie the top of the liner hanger (LH) and consequently prevent the running tool 100 being lowered beyond the position shown with respect to the liner hanger (LH). (In this connection the lug 24 has been illustrated displaced slightly anti-clockwise of its normal position to facilitate understanding of its operation.)
However, if the tool string is rotated anti-clockwise the lugs 24 come into alignment with longitudinally extending slots 28 in the liner hanger (LH). When this occurs the running tool 100 can be lowered sufficient to displace the body 25 of the liner support unit (LSU) (together with the support 25, ring 29, dogs 15, dog keepers 13, 14, valve seat 5, ball 4 and shear pin 12) downwards sufficient to bring the teeth units 16 into alignment with a recess 30 in the body 26 of the liner support unit LSU and thus allow the teeth 16 to move into the recess 30 and release the liner 1 from the running tool 100. It should perhaps be emphasised that the support 25 is fast with the body 26 of the liner support unit LSU whereas the ring 29 merely fits snugly over the body 16 but can be removed therefrom with the application of only a light force.
It will be appreciated that great care must be taken to ensure that the secondary release mechanism (SRM) does not operate inadvertently and accordingly the secondary release mechanism (SRM) includes a damper so that the lugs 24 can only come into alignment with the slots 28 if a sufficient anti-clockwise force, for example 3500 ft·lbs of left-hand torque, is applied to the drill string for a sufficient time, for example 30 seconds. In order to achieve this the secondary release mechanism (SRM) incorporates a damper unit which is better shown in FIG. 2. In particular, the damper unit comprises a rotor which forms part of the upper tubular member 3 of the running tool 100 and a stator 31 which is provided with three lugs 27 which project into the slots 28.
The rotor is provided with three radially outwardly extending vanes 33 whilst the stator 31 is provided with three radially inwardly extending vanes 34. The spaces between the vanes are filled with grease 36. In use, when an anti-clockwise force is applied to the running tool 100 the rotor attempts to move anti-clockwise. However, this movement is resisted by the grease which slowly oozes past the minute clearance between the radial extremities of the vanes 33 and the inside of the stator 31. This delays the lugs 24 coming into alignment with the slots 28 unless a sufficient anti-clockwise force is applied for a sufficient time. When a clockwise force is applied, as in normal operation, the stator 35 moves to the position shown in FIG. 2 where the vanes 33 abut the vanes 34. In this position clockwise rotation of the drill string is transmitted to the liner hanger LH via the lugs 27 and the slots 28.
Such rotation can be extremely helpful for facilitating the running of the liner 1 and during the subsequent cementation operation. In this connection, it will be noted that the liner hanger (LH) is provided with a bearing above the ring 11 to facilitate rotation of the liner 1 after the liner hanger (LH) has been set.
Historically, the practice at this stage would have been to completely withdraw the running tool 100 and then cement the liner 1 in position. However, the practice now is to raise the running tool 100 by a small distance to confirm that the liner 1 has been separated from the running tool 100 and then proceed with cementing through the drill string and running tool 100.
With this in mind, the top of the polished bore receptacle 22 is provided with a junk bonnet 20 which is intended to prevent material entering the polished bore receptacle 22 particularly during the cementing operation.
The junk bonnet 20 comprises a seal 19 which slidably engages the outer wall of the upper tubular member 3 and a seal 21 which engages the inner wall of the polished bore receptacle 22. The junk bonnet 20 is maintained in the polished bore receptacle 22 by teeth units 44 which project into grooves in the polished bore receptacle 22. The junk bonnet 20 is also restrained from rotation by a spring loaded pin 45 which is mounted in the junk bonnet 20 and which projects into a recess in the top of the polished bore receptacle 22 as shown.
The teeth units 44 are maintained in the radially extended position shown by a ring 46 which is held in place by a shear pin 43.
The bottom of the junk bonnet 20 is provided with an inwardly extending flange 35 which supports a plurality of hooks 47 which are biased radially inwardly by a resilient pad 48 but are restrained by a ring 49 secured to the junk bonnet 20 by a shear pin 50. The upper end of the hooks 47 rest on a bearing race 38 as shown.
In operation after the liner hanger LH has been set and the running tool 100 disconnected the running tool 100 is raised a short distance to confirm that disconnection has occurred. The running tool 100 is then lowered to relocate the lugs 27 in the slots 28.
Cementing then proceeds. This involves pumping cement down the drill string, through the running tool 100 and down the liner 1. The cement is supplied under pressure and consequently is squeezed up through the annular space between the liner 1 and the wellbore until it reaches the bottom of the well casing 2 when it passes up through the annular gap between the liner 1 and the well casing 2. During this time the liner 1 is rotated to enhance the distribution and compaction of the cement. Eventually the cement rises up between the liner 1 and the well casing 2 and a thin layer of cement covers the top of the junk bonnet 20.
At this time the running tool 100 is raised until the lip 32 enters the bottom of the junk bonnet 20. The lip 32 displaces the hooks 47 radially outwardly and then bears upwardly on the ring 49 until the shear pin 50 fails. As the ring 49 is pushed further up inside the junk bonnet 20 the hooks 47 move radially inwardly so that when the running tool 100 is lowered the lip 32 is supported on the hooks 47.
Downward force (typically 6800 kg (15,000 lbs)) is applied to the running tool 100. This force is applied to the junk bonnet 20 via the lip 32 and is transmitted to the polished bore receptacle 22.
It will be noted that when the running tool 100 was raised the stator 31 of the secondary release mechanism (SRM) also moved upwardly leaving the teeth units 51 connecting the polished bore receptacle 22 to the liner hanger LH unsupported. If the teeth units 51 have not already done so the application of downward force to the polished bore receptacle 22 displaces the teeth unit 51 inwardly and also shears sheet pin 37. As the polished bore receptacle 22 moves downwardly the packer 40 is squeezed downwardly and deformed outwardly against the well casing 2 by the core member 39. Further downward pressure (typically 18,200 kg (40,000 lbs)) fractures shear pin 41 causing the slip 42 to move outwardly over the cone member 39 and lock the packer 40 in position.
The running tool 100 is now raised so that the lip 32 bears against the ring 49 which in turn bears against the ring 46 until the shear pin 43 fails after which the teeth unit 44 can enter the recess in the ring 49 and the entire running tool 100 can be raised to the surface together with the valve seat 5, ball 4, teeth units 16 and any other debris which will have collected on the floor of the lower tubular member 17 below the port 18.
If it is not possible to fracture the shear pin 43 by a straight pull this may be accomplished by a combination of rotating the drill string and pulling. The spring loaded pin 45 facilitates this operation by preventing the junk bonnet 20 rotating in concert with the upper tubular member 3.
At the completion of the operation only the well casing 2, the liner 1, the liner hanger (LH), its components and the polished bore receptacle 22 should remain in the wellbore.
By way of background, it should be noted that the packer 40 is set to ensure fluid tightness between the liner 1 and the well casing 2 even though there is cement between these components It should also be noted that not all liners are cemented in place in which case the packer 40 is set immediately after the liner hanger (LH) has been set and the running tool 100 separated from the liner hanger (LH). | A system for setting a liner in a well casing which has a liner, a liner hanger, a polished bore receptacle, a packer which can be actuated by applying downward pressure to the polished bore receptacle, a running tool, and a junk bonnet which extends between the polished bore receptacle and the running tool and inhibits the ingress of debris into the polished bore receptacle, the junk bonnet and the running tool provided with apparatus which, when the running tool is raised without removing the junket bonnet from the polished bore receptacle, the apparatus cooperate so that when the running tool is subsequently lowered downward force applied to the running tool will be applied to the polished bore receptacle to set the packer, wherein the apparatus comprises a lip which extends radially outwardly from the running tool, and a hook which is biased radially inwardly from the junk bonnet and including a ring which is disposed to restrict radial inward movement of the hook but which can be displaced by the lip to allow such movement. | 19,416 |
FIELD OF THE INVENTION
This invention relates to inhalation activatable dispensers for use with inhalers such as dry powder dispersers and aerosol container assemblies which contain medicaments for inhalation therapy, are pressurized with liquid propellants, and include a metering valve through which a series of metered medicament doses can be dispensed. In particular the invention relates to inhalation activatable dispensers which are removably retained within an outer casing.
BACKGROUND TO THE INVENITON
Inhalation activatable dispensers for use with aerosol container assemblies of the type described above are known, their general purpose being to afford proper coordination of the dispensing of a dose of medicament with the inhalatin of the patient thereby allowing the maximum proportion of the dose of medicament to be drawn into the patient's bronchial passages. Examples of such dispensers are described in British Patent Specification Nos. 1,269,554, 1,335,378, 1,392,192 and 2,061,116 and U.S. Pat. Nos. 3,456,644, 3,645,645, 3,456,646, 3,565,070, 3,598,294, 3,814,297, 3,605,738, 3,732,864, 3,636,949, 3,789,843 and 3,187,748 and German Patent No. 3,040,641.
European Patent No. 147028 discloses an inhalation activatable dispenser for use with an aerosol container in which a latch mechanism releasing vane is pivotally mounted in an air passage between an aerosol outlet valve and a mouthpiece, which latch mechanism cannot be released if force to activate the dispenser is not applied before a patient inhales.
The dispenser generally comprises a housing having a mouthpiece and an air passage therethrough terminating at the mouthpiece, the housing being adapted to receive an aerosol container having a support block with a socket adapted to receive the stem of the valve of the aerosol container and a through orifice communicating between the socket and the air passage, and latch means having parts movable between an engaged position in which movement of the container and the support block toward each other upon the application of a force to bias the container and the support block toward each other is prevented and a release position in which movement of the container and the support block toward each other in response to said force is permitted causing the stem to move to its inner discharge position, the latch means comprising a vane mounted on the housing in the air passageway between the orifice and the mouthpiece for movement toward the mouthpiece under the influence of inhalation through the mouthpiece to release the latch means in which the vane moves toward the mouthpiece from a blocking to a nonblocking position with respect to the passageway in response to inhaling at the mouthpiece and releases the latch means only during the application of said force to bias the container and support block toward each other.
This inhalation device has been received favourably by patients and doctors since it not only overcomes the hand-lung coordination problem but it does so at a very low triggering flow rate (approximately 30 liters/minute) essentially silently, and with a very compact design barely larger than a standard inhaler.
It is an object of the present invention to provide an inhalation activable dispenser within an outer casing.
BRIEF SUMMARY OF THE INVENTION
Therefore according to the present invention there is provided:
(i) a breath-actuated inhaler comprising a medicament reservoir mounted within a housing which comprises a mouthpiece and breath-actuation means which prevents dispensing from the reservoir until a patient inhales through the mouthpiece, and,
(ii) a protective casing surrounding the breath actuated inhaler, the casing comprising a body portion and a movable cover which may be displaced to allow a patient access to the mouthpiece to use the breath-actuated inhaler whilst it is within the casing, the breath-actuated inhaler being removable from the protective casing and operable outside the casing.
The arrangement of a removable breath-actuated inhaler within a protective casing has several advantages. The casing surrounds and preferably completely envelopes the inhaler preventing ingress of dust, water and other foreign bodies allowing the inhalation device to be readily carried in a pocket, handbag etc. The inhaler may be used without removing it from the casing by displacing the cover to allow patient access to the mouthpiece. The casing also protects the inhaler, particularly the breath-actuated mechanism, from direct damage and if the casing is damaged the inhaler will probably still function from within the casing. However, if the casing is subjected to severe damage the inhaler may be removed and used in its breath-actuated mode outside the casing. In a preferred embodiment the breath-actuated inhaler comprises means to disable the breath-actuated mechanism thereby allowing the inhaler to be used in a simple press-and-breathe mode which allows test firing.
DESCRIPTION OF PREFERRED EMBODIMENTS
The inhaler preferably comprises an aerosol vial containing a mixture of propellant and medicament and equipped with a metering valve. However, the inhalation device of the invention may comprise a dry powder dispensing device in which the medicament is entrained in the air stream established by the patient's inspiratory effort. Examples of such devices are disclosed in our co-pending British Patent Application No. 8909891.7.
Suitable breath-actuated mechanisms for use in the inhaler are known and are described, for example, in European Patent No. 147028. The breath-actuated mechanism requires a priming or cocking force which moves the aerosol container relative to the valve stem for dispensing when the breath-actuated mechanism has been actuated. In one arrangement of the invention the priming force may be provided by a cocking lever mounted through the protective casing or may be provided by a screw arrangement or when the cover is displaced e.g. by a sliding, lever, geared or cam action or a combination thereof. Alternatively, access to a cocking lever may be gained when the cover is displaced. The priming force may be applied directly to the aerosol container or to the valve e.g. via a nozzle block assembly. The priming force is preferably applied by the cover which may be pivotally mounted to displace upwardly or downwardly to provide access to the mouthpiece. Generally the priming force applied by the cocking lever, cover etc., results in compression of a spring which moves the aerosol container relative to the valve when the breath-actuated mechanism is triggered. When the inhaler is removed from the casing the priming force may be applied manually by squeezing the aerosol container and housing between thumb and finger in a similar manner to a conventional press-and-breathe inhaler.
Alternatively, the inhaler may possess its own cocking lever to apply the primary force when the inhaler is removed from the casing. When the inhaler is within the casing the cocking lever may be uncovered for use when the cover is displaced or may interact with the cover to prime the inhaler during displacement of the cover.
The inhaler is preferably capable of accommodating aerosol vials of different lengths to avoid the necessity of producing completely different devices for each size of vial. Different length vials may be accommodated by forming the body portion of the casing in two or more parts, one part being in the form of a sleeve or shroud which envelops the base and at least part of the body of the aerosol vial. A series of such sleeves may be fabricated to correspond to different lengths of aerosol vials. Alternatively, the body portion of the casing may have an aperture through which the aerosol vial extends thereby obviating the need for producing a range of different size components.
The inhaler preferably incorporates means to provide an indication of the number of doses dispensed and/or remaining in the aerosol container. The indication is preferably visual and the housing of the inhaler and optionally the protective casing may have a transparent window or aperture for viewing.
The invention will now be described with reference to the accompanying drawings in which:
FIG. 1 represents a vertical cross-section through a breath-actuated inhaler suitable for use in the invention,
FIG. 2 represents a vertical cross-section through the breath-actuated inhaler of FIG. 1 during operation,
FIG. 3 represents a vertical cross-section through the breath-actuated inhaler of FIG. 1 in the press-and-breathe mode,
FIG. 4 represents a vertical cross-section through an inhalation device in accordance with the invention which comprises the breath-actuated inhaler of FIG. 1 within a protective casing,
FIG. 5 represents a vertical cross-section through the inhalation device of FIG. 4 showing the cover displaced,
FIGS. 6a and 6b represent a perspective view and a cross-section through an alternative inhalation device in accordance with the invention,
FIGS. 7a and 7b represent a perspective view and vertical cross-section through a further inhalation device in accordance with the invention,
FIGS. 8a and 8b represent a vertical cross-section through the upper portion of a further inhalation device in accordance with the invention,
FIGS. 9a and 9b represent a vertical cross-section through an upper portion of a further inhalation device in accordance with the invention, and
FIGS. 10a and 10b represent a vertical cross-section through an upper portion of a further inhalation device in accordance with the invention.
Referring to FIGS. 1 to 5, the breath-actuated inhaler comprises a housing (2) incorporating a mouthpiece (4) and contains an aerosol vial (6). The aerosol vial (6) may be of any suitable size and has a metering valve (not shown) possessing a hollow valve stem (8). The valve stem (8) is held within a nozzle block (10) which has a passage (12) in communication with the mouthpiece (4). Discharge of the metering valve is effected by relative movement between the valve stem (8) and the aerosol vial (6).
The breath-actuation mechanism comprises a vane (14) which is pivotally mounted within the mouthpiece (4), a rocker element (15) which supports a catch (16) pivotally mounted on the rocker at (18). When the breath-actuated mechanism is in its blocking position as shown in FIG. 1 and a cocking force is applied in the direction of the arrows A, movement of the aerosol vial (6) relative to the valve stem (8) is prevented. Such movement is blocked by the rocker element (15), which is prevented from pivotal movement by the catch (16) having a curved surface (17) engaging the curved surface (20) of the vane (14). Thus, when the inhaler is in its breath-actuated mode it is not possible to dispense from the aerosol vial before inhalation through the mouthpiece (4).
When a patient inhales through the mouthpiece as shown in FIG. 2, inhalation causes pivotal movement of the vane. The curved surface (20) of the vane (14) and the curved surface (17) of the catch (16) effectively act as co-operating roller surfaces. Pivotal movement of the vane causes the curved surface (20) to rotate in one direction resulting in curved surface (17) of the catch rotating in the opposite direction. This displacement of the catch moves from a blocking to an unblocking position allowing pivotal movement of the rocker element (15) which in turn allows movement of the vial (6) relative to the valve stem (8) under the influence of the cocking pressure causing the valve to fire.
The inhaler also comprises a switch (22) which may convert the inhaler between a breath-actuated mode and a press-and-breathe mode as may be required for test firing. The switch (22) is pivotally mounted within the housing (2) and comprises a finger (24) which is capable of engaging the catch (16). When the switch (22) is in the breath-actuated mode as shown in FIGS. 1 and 2 there is no engagement between the finger (24) and the catch (16). However, when the switch (22) is pivoted to the press-and-breathe mode as shown in FIG. 3, the finger (24) engages the catch (16), pivoting the catch (16) away from the vane (14) to its unblocking position thereby allowing free movement of the aerosol vial (6) relative to the valve stem (8). In the press-and-breathe mode the valve may be fired at any time. During use the patient will be required to coordinate the cocking force and breathing in order to attain an effective dose. The vane (14) will simply pivot to the roof of the mouthpiece during inhalation.
The breath-actuated inhaler additionally comprises means to provide an indication of the number of doses dispensed and/or an indication of the number of doses remaining. The indicator means comprises a ring (26) mounted for rotation about the aerosol vial, the ring having a plurality of circumferential teeth (28) which co-operate with a plurality of tines (30) mounted on the housing. During the reciprocatory motion of the aerosol vial when the valve is operated one or more of the tines (30) abuts a cam surface on one or more of the teeth (28) causing rotation of the ring (26) by a small increment. Suitable indication markings are present on the side of the ring (26) which may be viewed through a transparent window (32) in the housing to provide the patient with an indication of the contents remaining. Examples of such means for providing an indication of the contents of an inhaler are disclosed in our co-pending British Patent Application No. 8913893.7, dated 16th June, 1989.
FIGS. 4 and 5 of the accompanying drawings illustrate the breath-actuated inhaler of FIGS. 1 to 3 positioned within a protective casing generally shown at (34). The casing comprises a body portion (36) and a movable cover (38). The protective casing completely envelopes the inhaler preventing ingress of dust and other contaminates and provides robust protection against percussion damage should the inhalation device be dropped etc.
In the embodiment shown in FIGS. 4 and 5 the movable cover (38) is pivoted about pivot point (40) and has a forward protecting extension (39) which when closed fills the gap between pivot (40) and the casing. As the cover is pivoted, this extension (39) acts as a cam (42) on the bar of the inhaler and lifts it up against spring (48). After 90° of movement flange (44) is lifted above first step (45) on projection (46) on the protective cover and is retained on second step, where it remains during remainder of cover movement. On closing, the cover disengages flange (44) from step (45) and allows it to return to original position. Thus, a patient may simply open the cover of the casing and inhale through the mouthpiece to receive a dose of medicament.
The breath-actuated inhaler is retained within the protective cover by a flange (44) on the housing engaging projection (46) on the interior of the protective cover. The inhaler may simply be removed by pushing the inhaler upwards against the cocking spring (48) until the flange (44) and projection (46) disengage and then the inhaler may be readily pulled from the protective casing.
The breath-actuated inhaler may be inserted within the protective cover by fully opening the cover, pushing the top of the inhaler up against the cocking spring and inserting the base until the flange (44) engages the projection (46). When the cover is closed the breath-actuated inhaler will automatically be converted to the breath-actuated mode, even if it is in the press-and-breathe mode, by flange (25) on the cover pushing switch (22) to the breath-actuated position.
It will be readily appreciated that the protective casing may be constructed in a number of different configurations and it is not necessary for the opening of the cover to automatically apply a cocking force to the inhaler. The arrangement of FIG. 6a and 6b comprises a body portion (36) and a cover (38) which is pivotally mounted about pivot point (40). Opening of the cover (38) does not apply a cocking force to the breath-actuated inhaler. Cocking lever (50) is provided at the top of the protective cover and is constructed and arranged such that upon pivoting the cocking lever (50) downward pressure is applied to the aerosol vial of the breath-actuated inhaler (FIG. 6b).
FIGS. 7a and 7b illustrate an alternative form of protective casing comprising a body portion (36) and a movable cover (38) which is pivoted from a point at the top of the body portion and provides a cocking force to the inhaler as the cover (38) is opened.
FIGS. 8a and 8b of the accompanying drawings illustrate a breath-actuated inhaler in accordance with the invention in which the protective casing (34) may be modified to accommodate aerosol vials of different length. The body portion (36) of the casing has an aperture (80) through which a shroud (82) extends which accommodates the aerosol vial (not shown). A series of shrouds (82) may be fabricated having different lengths in order to accommodate various sizes of aerosol vial.
Whilst a cocking spring may be positioned within the top of the shroud (82), in a similar manner to the cocking spring (48 shown in FIG. 4), to absorb and retain the cocking force applied when the cover (38) is opened (as described with reference to FIG. 4) a cocking spring external of the shroud (82) may be employed. The shroud (82) is provided with a flange (84) and cocking spring (86) is positioned around the shroud (82) extending between the flange (84) and a stop or the top of the protective casing (88). When the cover (38) is opened, the breath-actuated inhaler, together with the shroud (82) is lifted (FIG. 8b) compressing cocking spring (86). When the patient breathes through the mouthpiece (4), the breath-actuated mechanism is triggered moving the shroud (82) and aerosol vial downwards to fire the aerosol valve.
FIGS. 9a and 9b of the accompanying drawings illustrate an alternative cocking mechanism which may be incorporated into the protective casing of an inhalation device in accordance with the invention. The body portion (36) of the protective casing may comprise a separate upper portion (90) which envelopes the end of the aerosol valve (6). Cocking spring (48) is positioned within the upper portion of the casing (90) to act against the base of the aerosol vial (6). The upper portion (90) is retained on the body portion (36) of the protective casing by complimentary flanges (92 and 94) which constitute a thread segment such that rotation of the upper portion (90) in the direction of the arrow X (FIG. 9b) causes the upper portion (90) to move down the body portion (36) thereby compressing cocking spring (48) and applying the necessary cocking force for the breath-actuated mechanism.
FIGS. 10a and 10b illustrate an inhalation device in accordance with the invention which incorporates the features of FIGS. 8 and 9. The top of the protective casing comprises an upper portion (90) through which extends a shroud (82) whose length is selected to accommodate the particular size of aerosol vial (6). Cocking spring (86) extends between flange (84) on the shroud and a stop or top (88) of the upper portion (90) and is compressed by downward movement of the upper portion (90) upon rotation in the direction of the arrow X. When the patient breathes through the mouthpiece (not shown) the breath-actuated device is triggered and the shroud (82) moves downwardly under the influence of the spring (86) thereby firing the aerosol valve.
In a further embodiment of the invention (not illustrated in the drawings) the shroud (82) shown in FIGS. 8 and 10 may be dispensed with and replaced by a circumferential flange extending around the aerosol vial, equivalent to flange (84), against which cocking spring (86) will act. The circumferential flange may be fabricated as a snap-on component around the aerosol vial e.g., in the region of the neck of the vial. This arrangement will obviate the need for fabricating a series of shrouds to accommodate the different sizes of aerosol vial, since the aerosol vial will simply extend through the top of the protective casing. | An inhalation device comprising:
(i) a breath-actuated inhaler comprising a medicament reservoir mounted within a housing which comprises a mouthpiece and breath-actuation means which prevents dispensing from the reservoir until a patient inhales through the mouthpiece, and,
(ii) a protective casing surrounding the breath actuated inhaler, the casing comprising a body portion and a movable cover which may be displaced to allow a patient access to the mouthpiece to use the breath-actuated inhaler while it is within the casing, the breath-actuated inhaler being removable from the protective casing and operable outside the casing. | 20,437 |
FIELD OF THE INVENTION
The present invention relates to a laser printing system for forming images by scanning a photosensitive member with a laser beam for exposure.
BACKGROUND OF THE INVENTION
Electrophotographic printers having a laser as the light source generally include an optical device which comprises the laser light source, laser beam shaping means and a beam scanning assembly. In recent years, such printers have been required to have a dot density (DPI: dots/inch) in the range of 100 to 1000, whereas different dot densities need different optical devices, consequently necessitating different printers.
Accordingly, Unexamined Japanese Patent Application No. SHO 59-117372 proposes a printer which is adapted to selectively give one of a plurality of different dot densities by automatically collectively controlling the laser beam diameter, laser modulation frequency, speed of rotation of a polygonal mirror for scanning with the beam and speed of rotation of the photosensitive drum.
However, since the prior-art printer has a single optical device which has a variable beam diameter, laser modulation frequency and rotational speed of the polygonal mirror, the device is complex in construction and becomes large-sized. Moreover there is a limitation to the speed of the motor in varying the speed of the polygonal mirror, and a higher speed results in impaired durability and a lower speed involves uneven rotation. The use of one optical device thus imposes limitations on the range of dot density variations, so that there arises a need to prepare different printers for widely varying dot densities.
SUMMARY OF THE INVENTION
Accordingly, the primary object of the present invention is to provide a laser printing system having a wider range of dot density variations although the system is of the single printer type.
Another object of the invention is to provide a laser printing system wherein the dot density is variable easily.
Another object of the invention is to provide a laser printing system which is easy to repair when the laser optical device thereof malfunctions and which is also easy to maintain.
Still another object of the invention is to provide a laser printing system which is adapted to produce prints in different colors each at a suitable dot density.
The foregoing objects can be fulfilled by providing a laser printing system comprising:
a main body including a photosensitive member; and
an optical unit for forming an image on the photosensitive member by projecting a laser beam thereon, said unit being exchangably provided in said main body and being selected from a plurality of units each having a different dot density, and comprising;
a laser beam source,
means for driving the laser beam source,
means for shaping the laser beam,
means for scanning the surface of said photosensitive member with the laser beam, and
means for giving an instruction as to the dot density of said unit to said main body;
wherein said main body forms the image at the dot density according to the instruction corresponding to the selected optical unit.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects or features of the present invention will become apparent from the following description of preferred embodiments thereof taken in conjunction with the accompanying drawings, in which:
FIGS. 1 and 2 are respectively a diagram and a perspective view schematically showing the construction of a laser printing system according to a first embodiment of the invention;
FIG. 3 is a diagram showing the construction of an optical unit included int he first embodiment;
FIG. 4 is a block diagram showing how the first embodiment is controlled;
FIG. 5 is a block diagram showing how the form of modified from the first embodiment is controlled.
FIG. 6 is a diagram showing the construction of a laser printing system according to a second embodiment of the invention; and
FIG. 7 is a diagram showing the construction of a laser printing system according to a third embodiment of the invention.
In the following description, like parts are designated by like reference numbers throughout the several drawings.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 and 2 are a diagram and a perspective view schematically showing the construction of the first embodiment, i.e., a laser printing system.
The system per se is adapted for practicing a known electrophotographic process and has a photosensitive drum 1 disposed in its center and drivingly rotatable in the direction of arrow a. Arranged around the drum 1 are a sensitizing charger 2, a magnetic brush developing unit 3, a transfer charger 4, a cleaner 5 of the blade type and an eraser lamp 6. The surface of the drum 1 is first charged to a predetermined potential by the charger 2 and the irradiated with a laser beam from the optical unit 20 to be described below in detail to form an electrostatic latent image on the drum surface. The latent image is converted to a visible image by the deposition of tone by the developing unit 3. By the discharge of the transfer charger 4, the toner image is transferred onto copy paper fed from a paper cassette 10 through a path indicated by a two-dot-and-dash line and is thermally fixed to the paper by a fixing unit 11. The copy paper is thereafter delivered onto a discharge tray 12.
On the other hand, the photosensitive drum 1 continues to rotate in the direction of arrow a after the image transfer, cleaned by the cleaner 5 for the removal of the residual toner, irradiated by the eraser lamp 6 for the removal of the residual charge and made ready for the subsequent copying cycle.
The optical unit 20 is int he form of a cartridge having a case 21 with a handle 22 and can be removably installed in position within the main body of the system from the front side thereof by being guided along unillustrated guide rails or the like.
The optical unit 20 has inside the case 21 a laser diode 25 serving as a light source, a collimator lens 26, a polygonal mirror 27, a drive motor 28 for rotating the mirror, SOS lens 29, reflecting mirror 30 and SOS sensor 31.
The laser beam emitter by the laser diode 25 and spreading out to some extent is collimated by the collimator lens 26, deflected by the polygonal mirror 27 and projected via the fθ lens 29 and the reflecting mirror 30 onto the drum 1 parallel to the axis thereof, i.e., along the main scanning line L. The SOS sensor 31 has the function of correcting an error in the recording start position in each scan line due to the errors involved in the division of the mirror surface of the polygonal mirror 27. To detect the image start position in the main scanning direction, the sensor is position in equivalent relation to the main scanning line L on the surface of the photosensitive drum 1.
With the above arrangement, the relationship between the dot density and various optical factors is represented by the following equations. It is herein assumed that the dot density in the main scanning direction is identical with that in the subscanning direction.
Beam diameter (d): d-C.sub.1 /D (1)
Number of revolutions (R) of the polygonal mirror: R=C.sub.2.D.V/N (2)
Modulation frequency (f): f=C.sub.3.F.D.sub.2.V/N (3)
Amount of light (E): E=C.sub.4.P.sub.0.N(F.V) (4)
wherein
C 1 -C 4 : proportional constant
D: dot density
V: peripheral speed of the drum
N: number of polygonal mirror faces
F: focal distance of the fθ lens
P 0 : output of the laser diode
The beam diameter (d) is determined from Equation (1) based on the dot density (D). In the optical unit 20, the beam diameter (d), for example, can be varied by using a different beam expander or prism or varying the focal distance of the collimator lens 26.
According to the present embodiment, the dot density (D) is variable by changing the optical unit 20. Accordingly, different optical units 20 with different dot densities are prepared, such that when it is assumed that the peripheral speed V of the photosensitve drum is constant, all or one of the rotational speed (R) of the polygonal mirror, the number (N) of the polygonal mirror faces, the modulation frequency (f) and the focal distance (F) of the fθ lens in each optical unit 20 is altered in accordance with the dot density thereof.
When the number of polygonal mirror faces, (N), is given, the number of revolutions (R) of the polygonal mirror is determined from Equation (2) according to the dot density (d). If the modulation frequency (f) is constant, Equation (3) gives the focal distance (F) of the fθ lens. Equation (4) reveals that at varying dot densities (D), the amount of light on the drum can be made constant by varying the laser output (P 0 ).
On the other hand, Equation (3) indicates that when the modulation frequency (f) and the fθ lens focal distance (f) are constant, the dot density (D) can be varied by altering the number of polygonal mirror faces, (N).
However, to obtain varying focal distances (F) or varying numbers of polygonal mirror faces, it is necessary to prepare a plurality of fθ lenses 29 or polygonal mirrors 27 in accordance with the dot densities of different optical units, at a greatly increased cost.
Equations (2) and (3) show that the dot density (D) is readily variable by altering the number of revolutions (R) of the polygonal mirror and the modulation frequency (f) when the fθ lens focal distance (F) and the polygonal mirror face number (N) remain constant. Equation (2) indicates that the polygonal mirror speed (R) is proportional to the dot density (D). Equation (3) shows that the modulation frequency (f) is in proportion to the square of the dot density (D).
The above description reveals that when optical units 20 with different dot densities are prepared, one of a plurality of different dot densities is selectively available simply changing the optical unit cartridge.
For the different optical units 20 to provide varying dot densities (D), it is practically most feasible to vary the number of revolutions (R) of the polygonal mirror and the modulation frequency (f) as already described. With the present embodiment, the optical unit 20 includes an oscillation circuit 40 which comprises a basic clock circuit (clock signal generating circuit) 40a and a frequency divider circuit 40b for controlling the number of revolutions (R) of the polygonal mirror 27 and the modulation frequency (f) of the laser diode 25.
More specifically stated with reference to FIG. 4, the oscillation circuit 40 feeds frequency data to a polygonal mirror drive circuit 41 within the optical unit 20 to drive the polygonal mirror motor 28 at a speed (R) predetermined for the particular unit 20 concerned. Further the oscillation circuit 40 feeds modulation frequency date (f) to image control means of a mechanical control circuit 43 provided int he system main body and including a microcomputer. In the image control means, the data is combined with image data from a character generator 44 to give LD data (pulse width and pulse on-off data), which is fed to the laser diode drive circuit 42, causing the laser diode 25 to emit a laser beam on modulation.
On the other hand, the other signals to be given by the optical unit 20 to the mechanical control circuit 43 in the main body include a lock signal which is delivered from the drive circuit 41 when the speed of the polygonal mirror 27 has reach the predetermined value. and an SOS (synchronizing) signal which is produced from the SOS sensor 3 for determining the scanning start position. Also fed to the mechanical control circuit 43 is a paper size signal which is produced from a paper sensor 45 provided on the paper cassette 10 shown in FIGS. 1 and 2 for determining the image area.
The basic clock circuit 40a may alternatively be provided in the mechanical control circuit 43 in the main body. Also usable as the beam scanning means in place of the polygonal mirror 27 are a galvanomirror, holographic scanner, etc.
As already stated, the dot density (D) is variable by altering not only the polygonal mirror speed (R) but also the polygonal mirror face number (N). In other words, the desired dot density (D) can be obtained at a lower mirror speed (R) using a polygonal mirror having an increased number (N) of faces. Then a fall bearing is used, the mirror speed (R) is limited to about 10,000 r.p.m., and the permissible range is exceeded when the dot density (D) is higher than a certain level. In such a case, the speed (R) can be set within the permissible range of up to 10,000 r.p.m. by increasing the face number (N).
As shown in FIG. 4, the optical unit 20 feeds the modulation frequency data (f) and the polygonal mirror rotation frequency data (R) to the mechanical control circuit 43 in the main body, and the dot density (D) of the optical unit 20 is transmitted to the main body in terms of these two items of data. Other dot density (D) indicating signals may alternatively be used. The dot density thus transmitted to the system main body serves to indicate the image area, in other words, the dot number for the specified paper size and the dot number from the scanning start point to the end point. The dot density indicating signal may be delivered via the mechanical control circuit 43 to the character generator 44 so as to produce a pattern in accordance with the dot density.
Although the present embodiment has been described above based on the assumption that the dot density in the main scanning direction is identical with that in the subscanning direction, at least one of these do densities can be variable independently. Equations (1) to (3) can be interpreted as follows when the dot density (DM) in the main scanning direction and the dot density (DS) in the subscanning direction are considered separately.
Beam diameter in main scanning direction (dM): dM=C.sub.5 /DM (5)
Beam diameter in subscanning direction (dS): dS=C.sub.6 /DS (6)
Number of revolutions (R) of polygonal mirror: R=C.sub.7.DS.V/N (7)
Modulation frequency (f): f=C.sub.8.F.DM.DS.V/N=C.sub.9.F.DM.R (8)
where C 5 -C 9 are proportional constants.
The beam diameters (dM), (dS) in the main and subscanning directions are determined form Equations (5), (6) based on the dot densities (DM), (DS) in the main and subscanning directions, respectively. When the two beam diameters (dM), (dS) are different, the laser beam is elliptical in cross section.
Equation (7) shows that the dot density (DS) in the subscanning direction is dependent on the polygonal mirror speed (R) and the polygonal mirror face number (N). It is herein assumed that the peripheral speed of the photosensitive drum is constant as in the foregoing case. Accordingly, the dot density (DS) in the subscanning direction is variable by altering the mirror speed (R) and/or the mirror face number (N).
On the other hand, Equation (8) indicates that the dot density (DM) in the main scanning direction is dependent on the modulation frequency (f), the fθ lens focal distance (F) and the polygonal mirror face number (N). Accordingly, if the dot density (DS) in the subscanning direction is varied by altering the mirror speed (R), the dot density (DM) in the main scanning direction also will consequently be varied. The dot density (DS) can only be varied while keeping the other density (DM) at the specified value without any variation, by altering the modulation frequency (f) and/or the fθ lens focal distance (F). For example, the dot density (DS) in the subscanning direction only can be doubled by doubling the mirror speed (R) and also doubling the modulation frequency (f). The dot density (DM) in the main scanning direction then remains unchanged as will be apparent from Equation (8).
Conversely, the dot density (DM) in the main scanning direction only can be varied, for example, by altering the modulation frequency (f) only. In this case, the dot density (DS) in the subscanning direction remains unchanged.
It will be apparent from the above description that the dot densities (DM), (DS) in the main scanning and subscanning directions are also both variable independently of each other.
With reference to FIG. 5, an exemplary circuit construction of optical unit 20 will be described below which is adapted to vary the dot densities (DM), (DS) in the main scanning and subscanning directions indepently of each other. Throughout FIGS. 4 and 5, like parts are designated by like reference numbers, and the difference only will be described.
The construction of FIG. 5 comprises, in addition to the construction of FIG. 4, a polygonal mirror face number data generating circuit 47 disposed in the optical unit 20. The circuit 47 gives the mechanical control circuit 43 of the main body the data as to the polygonal mirror face number (N) of the optical unit 20.
The mechanical control circuit 20 recognizes the dot density (DM) in the main scanning direction with reference to the data as to the number of revolutions of the polygonal mirror, (R), and the data as to the laser diode modulation frequency, (f), from the oscillation circuit. The circuit 20 further recognizes the dot density (DS) in the subscanning direction with reference to the polygonal mirror frequency data (f), the mirror face number data (N) and the drum peripheral speed data (V) stored in the circuit 20. In accordance with the two dot densities, the circuit 20 conducts communications with the character generator 44 to prepare the desired LD data.
The dot densities in the main scanning direction and the subscanning direction are controllable independently of each other by the above construction. Data is handled, for example, according to the G3 standard of the facsimile system at densities of 8 pixels/mm in the main scanning direction and 3.85 lines/mm or 7.7 lines/mm in the subscanning direction. When optical units are prepared in conformity with these densities, output images can be produced by the present system for input data without the necessity of image edition. Further when an optical unit is used for main bodies which have a peripheral speed of he photosensitive drum, the main bodies will operate at the same dot density n the main scanning direction but differ in the dot density in the subscanning direction, consequently producing images which are enlarged or contracted in the subscanning direction. Such drawback can be overcome if each main body is equipped with a proper optical unit in conformity with the peripheral speed of its photosensitive drum.
According to the first embodiment described above, cartridges having different dot densities are prepared, one of which is selectively used to obtain the desired one of the dot densities. This enables a single printing system to produce widely varying dot densities. The present system is further easy to maintain because a malfunction, if it occurs, can be remedied by merely replacing the faulty cartrige.
A second embodiment of the invention will be described next.
The second embodiment is adated to form images in more than one color by incorporating a plurality of optical units, as well as a plurality of electrophotographic image forming units, each identical with the corresponding unit of the first embodiment.
FIG. 6 shows the second embodiment wherein electrophotographic units A and A' are arranged in series.
In FIG. 6, the same parts as those of the first embodiment individually in corresponding relation are designated by the same corresponding reference numerals, and a prime is attached to each reference numeral for the second unit A'. Copy paper is transported in the direction of arrow c as indicated by a two-dot-and-dash line. The first photographic unit A transfers an image to the paper, and the second unit A' forms another image as superposed on the first image.
With the second embodiment, optical units 20 and 20' are interchangeable and are each replaceable by an optical unit of different dot density. For example, suppose the first optical unit 20 has a dot density of 200 DPI, the first developing unit 3 contains a black toner, the second optical unit 20' has a dot density of 300 DPI, and the second developing unit 3' contains a red toner. Images of 200 DPI are then formed in black, and those of 300 DPI in red. For example, lines for which high resolution is required can be reproduced in red, and other characters in black, selectively.
If the optical units 20, 20' are interchanged, images of 200 DPI will be formed in red, and those of 300 DPI in black. When another optical unit of a still different dot density (e.g., 400 DPI) is prepared and installed into the system as a replacement, images can be formed in black or red at this dot density.
FIG. 7 is a diagram showing a third embodiment of the invention.
The third embodiment comprises one photosensitive drum 1 and arranged around the drum 1 are a sensitizing charger 2, an optical unit 20 and a developing units 3 filled with a developer containing a color toner which are arranged in a first stage, and a sensitizing charger 2', an optical unit 20' and a developing unit 3' filled with a developer containing a black toner which are arranged in a second stage. Further arranged around the drum are a transfer charger 4, a cleaner 5 and an eraser lamp 6.
With this embodiment, a first toner image is formed by the optical unit 20 and the developing unit 3, and the optical unit 20' and the developing unit 3' form another toner image superposed on the first image. The combined toner image is then transferred onto copy paper by a single transfer operation with the transfer charger 4.
The optical units 20 and 20' of the third embodiment are the same as those of the second embodiment and therefore will not be described in detail. The third embodiment is equivalent tot he second embodiment in the result achieved.
While the image forming elements for forming two-color images are arranged according to the above second and third embodiments, optical units which are identical or different in dot density may be arranged side by side for one set of image forming elements so as to selectively use one of the optical units. One of the optical units, when used more frequently than the other in this case, can be discarded and replaced by the less frequently used one, and a new optical unit installed in the latter position.
Although the present invention has been fully described by way of examples with reference to the accompanying drawings, it is to be noted that various changes and modifications will be apparent to those skilled in the art. Therefore, unless otherwise such changes and modifications depart from the scope of the present invention, they should be construed as being included therein. | A laser printing system including a main body having a photosensitive member and an optical unit for forming an image on the photosensitive member by projecting a laser beam thereon. The optical unit is detachably provided in said main body and has a laser beam source, a laser beam source drive circuit, a laser beam shaping member, and a polygonal mirror for scanning the surface of the photosensitive member with the laser beam. The optical unit gives to the main body an instruction as to the dot density especially assigned thereto. The main body forms the image at the dot density assigned to the optical unit which is selected from a plurality of optical units having different dot densities. Accordingly, the optical units having different dot densities are prepared so as to be selectively used to obtain the desired one of the dot densities. | 23,466 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a cascade scanning optical system having a pair of laser scanning optical systems which are arranged along the main scanning direction and controlled to operate in synchronization with each other so as to realize a wide scanning line. More specifically the present invention relates to an apparatus of such a cascade scanning optical system, having a pair of laser scanning optical systems, for synchronizing the rotation of a polygon mirror of one laser scanning optical system with the rotation of a polygon mirror of the other laser scanning optical system, to prevent a pair of scanning lines that are to be aligned, respectively generated by the pair of laser scanning optical systems, from being deviated from each other in the sub-scanning direction.
2. Description of the Related Art
A cascade scanning optical system having a plurality of laser scanning optical systems arranged along the main scanning direction to realize a wide scanning line is known. Such a type of scanning optical system is disclosed in Japanese Laid-Open Patent Publication No. 61-11720, published on Jan. 20, 1986. This publication discloses a cascade scanning optical system having a pair of laser scanning optical systems each having a laser beam emitter, a polygon mirror serving as a deflecting device, an fθ lens, etc. The pair of laser scanning optical systems are synchronously driven to emit respective scanning laser beams to a photoconductive surface (scanning surface) of a photoconductive drum on a common line thereon extending in parallel to the axial direction of the photoconductive drum. The pair of scanning laser beams respectively scan two adjacent ranges of the common line on the photoconductive surface so as to scan the photoconductive surface of the photoconductive drum in the main scanning direction in a wide range.
There is a fundamental problem to be overcome in such a type of cascade scanning optical system. Namely, how can a scanning line, made on the photoconductive drum by the scanning laser beam emitted from one laser scanning optical system of the cascade scanning optical system, be accurately aligned with another scanning line, made on the photoconductive drum by the scanning laser beam emitted from another laser scanning optical system of the cascade scanning optical system, so that the scanning lines are not apart from each other in either the main scanning direction or the sub-scanning direction, i.e., so as to form a straight and continuous scanning line through the combination of the separate scanning lines.
It is sometimes the case that each reflecting surface (scanning laser beam deflecting surface) of a polygon mirror used in the cascade scanning optical system slightly tilts from its original position. In the case where the angle of each reflecting surface of the polygon mirror of one laser scanning optical system is different from that of the other corresponding laser scanning optical system, the pair of scanning lines, which are respectively generated by the aforementioned corresponding reflecting surfaces forming a straight and continuous scanning line, will deviate from each other in the sub-scanning direction on the photoconductive drum. This results in a gap or deviation occurring between the two scanning lines in the sub-scanning direction, so that a straight and continuous scanning line will not be formed. A similar problem will arise in the case where one or both of the polygon mirrors rotate with a tremor or oscillation.
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a synchronizing apparatus of a cascade scanning optical system which can prevent a scanning line, made by the scanning laser beam emitted from one laser scanning optical system, and another scanning line, made by the scanning laser beam emitted from the other laser scanning optical system, from far deviating from each other in the sub-scanning direction on a scanning surface.
To achieve the object mentioned above, according to an aspect of the present invention, there is provided a cascade scanning optical system which includes: a first laser scanning optical system having a first polygon mirror, provided with a plurality of first reflecting surfaces, for deflecting a first scanning laser beam to scan a part of a scanning surface to generate a first scanning line; a second laser scanning optical system having a second polygon mirror, provided with a plurality of second reflecting surfaces, for deflecting a second scanning laser beam to scan another part of the scanning surface to generate a second scanning line, wherein the first and second laser scanning optical systems are arranged so as to align the first scanning line with the second scanning line at a point of contact therebetween in a main scanning direction to form a single scanning line; means for measuring a degree of tilt of each of the plurality of first reflecting surfaces and the plurality of second reflecting surfaces; and means for determining combinations of the plurality of first reflecting surfaces with the plurality of second reflecting surfaces in accordance with results of measurements of the measuring means so that the single scanning line is formed by any one of the combinations while minimizing a phase difference between a first phase formed by degrees of tilt of the plurality of first reflecting surfaces and a second phase formed by degrees of tilt of the plurality of the second reflecting surfaces.
Preferably, the determining means includes means for comparing the degrees of tilt of the plurality of first reflecting surfaces with the degrees of tilt of the plurality of the second reflecting surfaces to judge which reflecting surface of the plurality of first reflecting surfaces has the closest degree of tilt to a reflecting surface of the plurality of the second reflecting surfaces.
Preferably, the measuring means includes: a first position sensitive device for detecting a position of the first scanning laser beam in a sub-scanning direction perpendicular to the main scanning direction to determine the degree of tilt of each of the plurality of first reflecting surfaces; and a second position sensitive device for detecting a position of the second scanning laser beam in the sub-scanning direction to determine the degree of tilt of each of the plurality of second reflecting surfaces.
Preferably, the first position sensitive device is positioned outside a first optical path through which the first scanning laser beam passes to form the first scanning line, and wherein the second position sensitive device is positioned outside a second optical path through which the second scanning laser beam passes to form the second scanning line.
Preferably, the cascade scanning optical system further includes means for storing the degree of tilt of each of the plurality of first reflecting surfaces and the plurality of second reflecting surfaces.
Preferably, the storing means includes: a first memory for storing the degree of tilt of each of the plurality of first reflecting surfaces; and a second memory for storing the degree of tilt of each of the plurality of second reflecting surfaces.
Preferably, the determining means includes means for comparing the degrees of tilt of the plurality of first reflecting surfaces which are stored in the first memory with the degrees of tilt of the plurality of the second reflecting surfaces which are stored in the second memory to judge which reflecting surface of the plurality of first reflecting surfaces has the closest degree of tilt to a reflecting surface of the plurality of the second reflecting surfaces so as to determine the combinations.
Preferably, the measuring means and the determining means each start operating each time a power switch of the cascade scanning optical system is turned ON.
Preferably, the cascade scanning optical system further includes a drum having the scanning surface on a periphery of the drum.
Preferably, the first and second laser scanning optical systems are composed of the same optical elements.
Preferably, the first and second laser scanning optical systems are symmetrically arranged.
According to another aspect of the present invention, there is provided a synchronizing apparatus of a cascade scanning optical system, the cascade scanning optical system including a pair of laser scanning optical systems each having a polygon mirror provided with a plurality of reflecting surfaces, the pair of laser scanning optical systems being arranged to form a single scanning line, wherein the synchronizing apparatus includes: means for measuring a degree of tilt of each of the plurality of reflecting surfaces of the polygon mirrors; and means for determining combinations of the plurality of reflecting surfaces of one of the polygon mirrors with the plurality of reflecting surfaces of the other of the polygon mirrors in accordance with results of measurements of the measuring means so that the single scanning line is formed by any one of the combinations while minimizing a phase difference between a first phase formed by degrees of tilt of the plurality of reflecting surfaces of the one of the polygon mirrors and a second phase formed by degrees of tilt of the plurality of the reflecting surfaces of the other of the polygon mirrors.
The present disclosure relates to subject matter contained in Japanese Patent Application No. 8-348106 (filed on Dec. 26, 1996) which is expressly incorporated herein by reference in its entirety.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be described below in detail with reference to the accompanying drawings in which:
FIG. 1 is a perspective view of an embodiment of a cascade scanning optical system to which the present invention is applied, showing only fundamental elements thereof;
FIG. 2 is a plan view of a part of the cascade scanning optical system shown in FIG. 1;
FIG. 3A is a graph showing the degree of tilt of each reflecting surface of the first of the pair of polygon mirrors shown in FIG. 1 or 2 in one example;
FIG. 3B is a graph showing the degree of tilt of each reflecting surface of the second of the pair of polygon mirrors shown in FIG. 1 or 2 in the one example; and
FIG. 4 is a block diagram of a synchronizing apparatus of the cascade scanning optical system.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows an embodiment of a cascade scanning optical system for scanning the photoconductive surface of a photoconductive drum (rotating member) 10 provided in a laser-beam printer. The cascade scanning optical system is provided with a pair of laser scanning optical systems, i.e., a first scanning optical system 20A and a second scanning optical system 20B. The first and second optical systems 20A and 20B are each designed as a non-telecentric system, so that the incident angle of a scanning laser beam emitted from each of the first and second optical systems 20A and 20B relative to the photoconductive surface of the drum 10 varies in accordance with a variation in the position of the scanning spot of the scanning laser beam on the photoconductive surface in the main scanning direction. The first and second scanning optical systems 20A and 20B are provided with the same optical elements or parts, that is, the first scanning optical system 20A is provided with a laser collimating unit 21A serving as a laser beam emitter, a cylindrical lens 23A, a polygon mirror (scanning laser beam deflector) 24A, an fθ lens group 25A, an auxiliary lens 26A and a mirror 27A, while the second scanning optical system 20B is provided with a laser collimating unit 21B serving as a laser beam emitter, a cylindrical lens 23B, a polygon mirror (scanning laser beam deflector) 24B, an fθ lens group 25B, an auxiliary lens 26B and a mirror 27B. Each of the fθ lens groups 25A and 25B consists of two lens elements as can be seen from FIG. 1. The first and second scanning optical systems 20A and 20B are arranged side by side in a direction parallel to the axial direction of the drum 10 and are supported by a common casing 35 on an inner flat surface thereof.
The laser collimating units 21A and 21B are identical. Each of the laser collimating units 21A and 21B is provided therein with a laser diode LD and a collimating lens group (not shown) for collimating a laser beam emitted from the laser diode LD. In each of the first and second scanning optical systems 20A and 20B, the laser beam emitted from the laser diode LD is collimated through the collimating lens group. Thereafter this collimated laser beam is incident upon the cylindrical lens 23A or 23B positioned in front of the corresponding laser collimating unit 21A or 21B. Each cylindrical lens 23A or 23B has a power in the sub-scanning direction, so that the spot of the laser beam incident thereon is elongated therethrough in the main scanning direction to be incident upon the corresponding polygon mirror 24A or 24B. The polygon mirrors 24A and 24B are each rotated, so that laser beams incident thereon are deflected in the main scanning direction to proceed toward the mirrors 27A and 27B through the fθ lens groups 25A and 25B and the auxiliary lenses 26A and 26B, respectively. Subsequently, the laser beams incident upon the mirrors 27A and 27B are reflected thereby towards the photoconductive drum 10, to thereby scan the same in the main scanning direction.
Each of the auxiliary lenses 26A and 26B has a power mainly in the sub-scanning direction. In order to reduce the size of the cascade scanning optical system, it is possible to omit each of the auxiliary lenses 26A and 26B. In such a case, the design of the fθ lens groups 25A and 25B would be modified in such a way that they would have the equivalent power to that of the combined power of the original fθ lens groups 25A and 25B and the auxiliary lenses 26A and 26B, respectively. In FIG. 2, "X" represents an optical axis of the fθ lens group 25A or 25B. The optical axis X extends perpendicular to the main scanning direction. "S" represents the photoconductive surface of the drum 10. The auxiliary lenses 26A and 26B and the mirrors 27A and 27B are not illustrated in either FIG. 2 or 4.
The polygon mirror 24A rotates in a clockwise direction while the polygon mirror 24B rotates in a counterclockwise direction, as viewed in FIG. 2. Namely, the polygon mirrors 24A and 24B rotate in opposite rotational directions to scan the photoconductive surface of the drum 10 from its approximate center toward respective opposite ends in opposite directions. A mirror 28A is fixedly provided in the casing 35 at a position to receive the scanning laser beam emitted from the fθ lens group 25A before the scanning laser beam is incident on the photoconductive surface of the drum 10 through the auxiliary lens 26A and the mirror 27A at each scanning sweep while the polygon mirror 24A rotates. The laser beam reflected by the mirror 28A is incident on a laser beam detector (BD) 29A fixedly provided in the casing 35 at a position opposite to the mirror 28A. Likewise, a mirror 28B is fixedly provided in the casing 35 at a position to receive the scanning laser beam emitted from the fθ lens group 25B before the scanning laser beam is incident on the photoconductive surface of the drum 10 through the auxiliary lens 26B and the mirror 27B at each scanning sweep while the polygon mirror 24B rotates. The laser beam reflected by the mirror 28B is incident on a laser beam detector (BD) 29B fixedly provided in the casing 35 at a position opposite to the mirror 28B.
The laser diodes LD of the laser collimating units 21A and 21B are each controlled to turn its laser emission ON or OFF in accordance with given image data to draw a corresponding image (charge-latent image) on the photoconductive surface of the drum 10, and subsequently this image drawn on the photoconductive surface of the drum 10 is transferred to plain paper according to a conventional electrophotographic method. The polygon mirrors 24A and 24B are controlled synchronously with the use of the laser beam detectors 29A and 29B such that on the photoconductive surface of the drum 10 the scanning starting point of a spot of the scanning laser beam emitted from the first scanning optical system 20A is properly and precisely adjacent to the scanning starting point of a spot of the scanning laser beam emitted from the second scanning optical system 20B, and that those two spots move in opposite directions apart from each other in the main scanning direction to thereby form a wide scanning line on the photoconductive surface of the drum 10. With the rotational movement of the photoconductive drum 10 which is synchronized to the rotational movement of each of the polygon mirrors 24A and 24B, a series of wide scanning lines are made on the photoconductive surface of the drum 10 to thereby obtain a certain image (charge-latent image) on the photoconductive surface of the drum 10.
The polygon mirror 24A has a regular hexagonal cross section and is provided along a circumference thereof with six reflecting surfaces (scanning laser beam deflecting surfaces) A, B, C, D, E and F. Likewise, the polygon mirror 24B has a regular hexagonal cross section and is provided along a circumference thereof with corresponding six reflecting surfaces (scanning laser beam deflecting surfaces) a, b, c, d, e and f. In either polygon mirror 24A or 24B, there is a possibility of each reflecting surface tilting from its original position. Such tilt causes the position of the spot of the corresponding scanning laser beam to deviate on the photoconductive surface in the sub-scanning direction. In the case where the degree (amount) of tilt of one reflecting surface of the polygon mirror 24A is different from that of a corresponding reflecting surface of the polygon mirror 24B, opposing ends of two scanning lines to be combined which are formed by a pair of scanning laser beams on the photoconductive surface will be apart from each other in the sub-scanning direction. With a synchronizing apparatus which will be hereinafter discussed such a problem of deviation of opposing ends of the two scanning lines in the sub-scanning direction is effectively prevented from occurring.
A first PSD (semiconductor position sensitive device) 31A is fixedly provided in the casing 35 at a position in the vicinity of the laser beam detector 29A to receive the scanning laser beam emitted from the fθ lens group 25A after the scanning laser beam has completed a single scanning at each scanning sweep while the polygon mirror 24A rotates. Likewise, a second PSD (semiconductor position sensitive device) 31B is fixedly provided in the casing 35 at a position in the vicinity of the laser beam detector 29B to receive a laser beam emitted from the fθ lens group 25B after the scanning laser beam has completed a single scanning at each scanning sweep while the polygon mirror 24B rotates. Each PSD 31A, 31B detects the position of a scanning laser beam received, emitted from the corresponding polygon mirror 24A or 24B, in the sub-scanning direction so as to determine the degree of tilt of each reflecting surface of the corresponding polygon mirror 24A or 24B. FIG. 3A is a graph showing the degree of tilt of each reflecting surface (A, B, C, D, E and F) of the polygon mirror 24A while FIG. 3B is a graph showing the degree of tilt of each reflecting surface (a, b, c, d, e and f) of the polygon mirror 24B, in an example. As can be seen from FIGS. 3A and 3B, in either polygon mirror 24A or 24B the degree of tilt periodically varies to substantially form a sine curve. In the present embodiment a point at which the phases of the two sine curves coincides with each other most is determined to synchronize the rotation of the polygon mirror 24A with the rotation of the polygon mirror 24B so as to form a wide scanning line on the photoconductive surface of the drum 10 by a corresponding pair (determined pair) of reflecting surfaces of the polygon mirrors 24A and 24B. In the illustrated particular example shown in FIGS. 3A and 3B, a deviation of a pair of scanning lines respectively generated by the polygon mirrors 24A and 24B on the photoconductive surface in the sub-scanning direction will be greatly reduced or substantially eliminated if the rotation of the polygon mirror 24A is synchronized with the rotation of the polygon mirror 24B with the reflecting surface `A` of the polygon mirror 24A coincident with the reflecting surface `e` of the polygon mirror 24B, as will be appreciated from FIGS. 3A and 3B.
FIG. 4 shows a block diagram of the synchronizing apparatus of the cascade scanning optical system which realizes the aforementioned synchronizing process. The first and second polygon mirrors 24A and 24B are rotated by first and second motor units 55A and 55B, respectively. When the first and second motor units 55A and 55B start operating upon the power switch turned ON, the motor units 55A and 55B are each controlled, rotating with common clock pulses output from a frequency divider 53 which receives clock pulses from a clock pulse generator 51. After the rotation of each motor unit 55A, 55B has become stable and the PLL (phase-lock loop) starts, the rotational speed of the second polygon mirror 24B, i.e., the rotational speed of the second motor unit 55B, is controlled in accordance with signals which are output from the second laser beam detector 29B each time the first laser beam detector 29A detects the laser beam emitted from the first polygon mirror 24A.
The first laser beam detector 29A outputs a signal to both a first phase detecting circuit 57A and a phase-difference detector 59 at the time the first laser beam detector 29A detects a scanning laser beam. The second laser beam detector 29B outputs a signal to each of: a second phase detecting circuit 57B, the phase-difference detector 59, and a delay circuit (time-delay circuit) 81 at the time the second laser beam detector 29B detects a scanning laser beam. The phase-difference detector 59 determines a phase difference between the phase of signals output from the first laser beam detector 29A and the phase of signals output from the second laser beam detector 29B in accordance with the signals input from the first and second laser beam detectors 29A and 29B to output a phase difference indicating voltage to an LPF (low pass filter) 61. The terms "phase difference indicating voltage" herein used mean a voltage which indicates the magnitude of a phase difference. In the case where the phase of signals output from the second laser beam detector 29B follows the phase of signals output from the first laser beam detector 29A, the phase-difference detector 59 outputs a positive phase difference indicating voltage. Conversely, in the case where the phase of signals output from the second laser beam detector 29B precedes the phase of signals output from the first laser beam detector 29A, the phase-difference detector 59 outputs a negative phase difference indicating voltage.
Inputting a phase difference indicating voltage output from the phase-difference detector 59, the LPF 61 converts the phase difference indicating voltage into a DC voltage corresponding to the magnitude of the input phase difference indicating voltage. Subsequently, the LPF 61 outputs the DC voltage to a VCO (voltage controlled oscillator) 63. The VCO 63 changes the frequency of clock pulses output therefrom in accordance with the DC voltage input from the LPF 61 In this particular embodiment, the VCO 63 outputs clock pulses having a high frequency to a multiplexer 67 when the DC voltage input from the LPF 61 is a high voltage, while the VCO 63 outputs clock pulses having a low frequency to the multiplexer 67 when the DC voltage input from the LPF 61 is a low voltage. The multiplexer 67 adjusts clock pulses input from the frequency divider 53 in accordance with clock pulses input from the VCO 63 to output the adjusted clock pulses to the second motor unit 55B. Accordingly, in the case where the phase of signals output from the second laser beam detector 29B follows that of the first laser beam detector 29A, the rotational speed of the second motor unit 55B increases. Conversely, in the case where the phase of signals output from the second laser beam detector 29B precedes that of the first laser beam detector 29A, the rotational speed of the second motor unit 55B decreases.
When detecting a scanning laser beam, each PSD 31A, 31B outputs a voltage corresponding to the detected position of the received scanning laser beam. The voltage output from the first PSD 31A is converted into digital signals by an A/D converter 71A to be stored in a data memory 73A as data (first data group) representing the degrees of tilt of the reflecting surfaces A, B, C, D, E and F of the first polygon mirror 24A. Similarly, the voltage output from the second PSD 31B is converted into digital signals by an A/D converter 71B to be stored in a data memory 73B as data (second data group) representing the degrees of tilt of the reflecting surfaces a, b, c, d, e and f of the second polygon mirror 24B. It is preferable to measure each of the aforementioned first and second data groups more than once and store the average values of the first data group and the average values of the second data group in the data memories 73A and 73B, respectively, so as to improve the reliability of each of the first and second data groups.
After the degrees of tilt of the reflecting surfaces of the first polygon mirror 24A have all been stored in the data memory 73A, a reflecting-surface position detecting circuit 75A firstly detects the degree of tilt of any one of the reflecting surfaces of the first polygon mirror 24A, which rotates at a fixed rotational speed, by inputting a signal from the first PSD 31A through the A/D converter 71A. Subsequently the reflecting-surface position detecting circuit 75A inputs the values from the first data group stored in the data memory 73A and compares each stored degree of tilt in the first data group with the detected degree of tilt of the aforementioned reflecting surface of the first polygon mirror 24A to determine which one of the reflecting surfaces A, B, C, D, E or F of the first polygon mirror 24A is the aforementioned reflecting surface of the first polygon mirror 24A. Thereafter the reflecting-surface position detecting circuit 75A outputs the data (first surface data) representing one of the reflecting surfaces A, B, C, D, E or F of the first polygon mirror 24A which is the aforementioned reflecting surface of the first polygon mirror 24A, to a motor speed controller 77.
Likewise, after the degrees of tilt of the reflecting surfaces of the second polygon mirror 24B have all been stored in the data memory 73B, a reflecting-surface position detecting circuit 75B firstly detects the degree of tilt of any one of reflecting surfaces of the second polygon mirror 24B, which rotates at a fixed rotational speed, by inputting a signal from the second PSD 31B through the A/D converter 71B. Subsequently the reflecting-surface position detecting circuit 75B inputs the values of the second data group stored in the data memory 73B and compares each stored degree of tilt in the second data group with the detected degree of tilt of the aforementioned reflecting surface of the second polygon mirror 24B to determine which one of the reflecting surfaces a, b, c, d, e or f of the second polygon mirror 24B is the aforementioned reflecting surface of the second polygon mirror 24B. Thereafter the reflecting-surface position detecting circuit 75B outputs the data (second surface data) representing one of the reflecting surfaces a, b, c, d, e or f of the second polygon mirror 24B which is the aforementioned reflecting surface of the second polygon mirror 24B, to the motor speed controller 77.
The motor speed controller 77 compares the first surface data input from the reflecting-surface position detecting circuit 75A and the corresponding data stored in the data memory 73A which represents the degree of tilt of the aforementioned reflecting surface of the first polygon mirror 24A with the second surface data input from the reflecting-surface position detecting circuit 75B and the corresponding data stored in the data memory 73B which represents the degree of tilt of the aforementioned reflecting surface of the second polygon mirror 24B to determine a phase difference between the phase of the degrees of tilt of reflecting surfaces of the first polygon mirror 24A and the phase of the degrees of tilt of reflecting surfaces of the second polygon mirror 24B. Namely, it is determined which degree of tilt of the reflecting surfaces A, B, C, D, E or F of the first polygon mirror 24A is closest to which degree of tilt of the reflecting surfaces a, b, c, d, e or f of the second polygon mirror 24B. Thereafter, with the reflecting surfaces A, B, C, D, E and F of the first polygon mirror 24A regarded as reference surfaces, the motor speed controller 77 converts the phase difference into a voltage (phase difference indicating voltage) to be output to the LPF 61.
The LPF 61 converts the voltage input from the motor speed controller 77 into a DC voltage corresponding to the magnitude of the input voltage and outputs the DC voltage to the VCO 63. The VCO 63 varies the frequency of clock pulses output therefrom in accordance with the DC voltage input from the LPF 61. Due to the variation in frequency of clock pulses output from the VCO 63, the rotational speed of the second motor unit 55B is controlled to increase or decrease so as to match the phase of a sine curve formed by the degrees of tilt of the reflecting surfaces of the first polygon mirror 24A with the phase of a sine curve formed by the degrees of tilt of the reflecting surfaces of the second polygon mirror 24B, so that the combinations of the reflecting surfaces A, B, C, D, E and F with the reflecting surfaces a, b, c, d, e and f change, i.e., the correspondence of each of the reflecting surfaces A, B, C, D, E and F with a corresponding reflecting surface a, b, c, d, e or f changes. At the time the motor speed controller 77 detects a condition that the data representing the degree of tilt of any one of the reflecting surfaces A, B, C, D, E and F substantially corresponds to the data representing the degree of tilt of a corresponding reflecting surfaces a, b, c, d, e or f which is currently synchronized with the aforementioned any one of the reflecting surfaces A, B, C, D, E and F, the motor speed controller 77 stops outputting the voltage (phase difference indicating voltage) to the LPF 61 so as to maintain the current phase (correspondence of reflecting surfaces), which completes the synchronizing process of the present embodiment. Thereafter the synchronization of rotation of the first and second polygon mirrors 24A and 24B is maintained according to the phase difference indicating voltage output from the phase-difference detector 59.
In the illustrated particular example shown in FIGS. 3A and 3B, after the above synchronizing process has been completed, the reflecting surface A of the first polygon mirror 24A corresponds to the reflecting surface e of the second polygon mirror 24B. Accordingly, the motor speed controller 77 adjusts the rotational speed of the second motor unit 55B to synchronize the reflecting surface A of the first polygon mirror 24A with the reflecting surface e of the second polygon mirror 24B.
The motor speed controller 77 can determine the phase difference between the sine curve of the degrees of tilt of reflecting surfaces of the first polygon mirror 24A and the sine curve of the degrees of tilt of reflecting surfaces of the second polygon mirror 24B, using all the aforementioned data input from each of the data memories 73A and 73B and the reflecting-surface position detecting circuits 75A and 75B, in accordance with either one of the following two practical methods.
[First method]
Regarding each of the first and second polygon mirrors 24A and 24B, among the data representing the degrees of tilts of the six reflecting surfaces a specific reflecting surface whose degree of tilt is the largest is ranked as Level 3. The other five reflecting surfaces which follow the specific reflecting surface in time order are ranked Levels 4, 5, 6, 1 and 2, respectively. In the example shown in FIG. 3A the reflecting surface B is ranked as Level 3. In the example shown in FIG. 3B the reflecting surface f is ranked as Level 3.
Thereafter, one of the reflecting surfaces of the second polygon mirror 24B which is currently synchronized with the aforementioned specific reflecting surface of the first polygon mirror 24A whose degree of tilt is the largest is detected. Subsequently the Level value of the detected one of the reflecting surfaces of the second polygon mirror 24B is subtracted from the Level value of the aforementioned specific reflecting surface. The larger the absolute value of the result of such a subtraction is, the larger the phase difference is. Therefore, an amount of variation in the number of revolutions of the second polygon mirror 24B per a certain period of time can be determined based on the result of the aforementioned subtraction. At the same time, by knowing whether the result of the subtraction is a negative value or a positive value, it can be judged whether the phase of the sine curve representing the degrees of tilt of reflecting surfaces of the second polygon mirror 24B precedes or follows the phase of the sine curve representing the degrees of tilt of reflecting surfaces of the first polygon mirror 24A, i.e., whether the number of revolutions of the second polygon mirror 24B per a certain period of time should be increased or decreased can be determined. This operation is completed when the result of the aforementioned subtraction becomes zero (0). In this first method, although a specific reflecting surface whose degree of tilt is the largest is ranked as Level 3, a specific reflecting surface whose degree of tilt is the smallest may be ranked as Level 3 (reference level).
[Second Method]
The value of the degree of tilt of the reflecting surface `a` is subtracted from the value of degree of tilt of one of the reflecting surfaces A, B, C, D, E and F which is currently synchronized with the reflecting surface `a`, and the result of that subtraction is stored in memory. Similarly, the value of the degree of tilt of the reflecting surface `b` is subtracted from the value of the degree of tilt of another one of the reflecting surfaces A, B, C, D, E and F which is currently synchronized with the reflecting surface `b`, and the result of that subtraction is stored in memory. A similar operation is performed for each of the remaining four reflecting surfaces c, d, e and f. After all the six results have been obtained, the number of revolution of the second polygon mirror 24B per a certain period of time is adjusted such that the sum of the absolute values of the six results will be minimal.
The processing in either the first or second method can start to be performed each time the power switch of the apparatus is turned ON, i.e. each time the first and second motor units 55A and 55B start operating, or during the idle of each motor units 55A, 55B at the time a certain period of time elapses after the power switch of the apparatus is turned ON.
In FIG. 4, "HSYNC 1" and "HSYNC 2" shown on the left side of the drawing each represent a reference signal for commencing an operation of writing main scanning data. A delay circuit (time-delay circuit) 81 delays the output signal by a specific time interval with respect to the input signal, so that the commencement of each scanning sweep made by the second scanning optical system 20B is delayed by the aforementioned specified time interval with respect to the commencement of each scanning sweep made by the first scanning optical system 20A. The data of the specified time interval (delay-time data) is prestored in memory 79, so that the delay circuit 81 inputs the delay-time data from the memory 79 and outputs the reference signal HSYNC 2 in accordance with the delay-time data.
As can be understood from the foregoing, according to the present embodiment of the cascade scanning optical system, a deviation between a scanning line made by the scanning laser beam emitted from one laser scanning optical system and another scanning line made by the other laser scanning optical system, which are to be aligned to form a straight and continuous scanning line, can be fallen into an acceptable range of deviation.
Obvious changes may be made in the specific embodiments of the present invention described herein, such modifications being within the spirit and scope of the invention claimed. It is indicated that all matter contained herein is illustrative and does not limit the scope of the present invention. | A cascade scanning optical system which includes: a first laser scanning optical system having a first polygon mirror, provided with a plurality of first reflecting surfaces, for deflecting a first scanning laser beam to scan a part of a scanning surface to generate a first scanning line; a second laser scanning optical system having a second polygon mirror, provided with a plurality of second reflecting surfaces, for deflecting a second scanning laser beam to scan another part of the scanning surface to generate a second scanning line, wherein the first and second laser scanning optical systems are arranged so as to align the first scanning line with the second scanning line at a point of contact therebetween in a main scanning direction to form a single scanning line; means for measuring a degree of tilt of each of the plurality of first reflecting surfaces and the plurality of second reflecting surfaces; and means for determining combinations of the plurality of first reflecting surfaces with the plurality of second reflecting surfaces in accordance with results of measurements of the measuring means so that the single scanning line is formed by any one of the combinations while minimizing a phase difference between a first phase formed by degrees of tilt of the plurality of first reflecting surfaces and a second phase formed by degrees of tilt of the plurality of the second reflecting surfaces. | 37,506 |
CROSS REFERENCES TO RELATED APPLICATIONS
This application is a division of Ser. No. 14,005 filed Feb. 21, 1979 now abandoned which was a continuation of Ser. No. 851,651 filed Nov. 15, 1977 now abandoned, which was a continuation-in-part of Ser. No. 673,567 filed Apr. 5, 1976 now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
In one aspect, this invention relates to vacuum distillation systems. In another aspect, this invention relates to closed loop waste treating systems. In yet a further aspect, this invention relates to methods of using distillation systems.
2. Description of the Prior Art
Prior art distillation systems wherein a variable speed compressor is used to put energy into a vapor which is in turn condensed to give off latent heat of vaporization to a distilland are known in the art. One example of such a system is shown by U.S. Pat. No. 2,446,880. These systems have been primarily used for water desalinization and operate at temperatures near or even above the boiling point of water at atmospheric pressure.
Such systems are not desirable for distilling fruit juices or plating solutions; since they must be concentrated at temperatures well below the boiling point of water to prevent degradation of the organic materials present.
SUMMARY OF THE INVENTION
It is an object of this invention to provide an improved method of controlling the vapor compression process. The vapor compression system of this invention has an evaporation chamber maintained at a reduced pressure, a concentration chamber for holding the distilland to be concentrated, a density measuring means for measuring distilland density, and an evaporation surface connecting to the concentration and evaporation chambers. This configuration allows the distilland to be retained within the concentration chamber until the desired distilland concentration measured as a function of density is obtained.
As a further feature of this invention, the compressor capacity is increased until the compressor reaches a surge condition and the compressor capacity is reduced an incremental amount to bring the compressor into the desired operating range.
BRIEF DESCRIPTION OF THE DRAWINGS
In the accompanying drawing:
FIG. 1 is a schematic drawing of a plating line which includes a vapor compression unit of this invention and is adapted for closed loop operation;
FIG. 2 is a side elevation view in partial section of a vapor compression unit incorporating features of this invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A typical plating schematic using a vapor compression still is shown in FIG. 1. Parts to be plated are placed in a plating tank 12 which contains a solution of ions to be deposited on the parts as a metal layer. After a metal layer has been deposited on the parts, the plated parts are moved successively to rinse tanks 14, 16, 18 where any plating solution clinging to the plated part is rinsed off.
A substantial amount of plating solution, containing valuable metal ions and organic additives, is carried into the rinse tanks. Also, some water is carried from tank to tank by the parts as they are rinsed. The carry over and evaporation from the rinse tanks depletes the water in the rinse tanks and the concentration of plating solution will steadily rise, especially in the first rinse tank 14.
A portion of the water in the first rinse tank 14 is periodically withdrawn from the bottom of the tank and sufficient water from the second tank 16 is transferred via line 15 to refill tank 14. The tank 16 is refilled from tank 18 via line 17 and tank 18 is in turn filled by purified water from a vapor compression still 20 via line 19. Additional water can be added from an outside source of fresh water 21 when needed.
As shown, the rinse water or distilland from the first rinse tank 14, is withdrawn at outlet 22 by opening valve 24. The contaminated rinse water is conveyed by a pipe 26 to a heat exchanger 28 where the rinse water extracts some heat from purified water condensed in the vapor compression still 20. The preheated rinse water passes through a three-way valve 30 and is fed to the vapor compression still from the rinse water. The rinse water is concentrated to a density suitable for return to the plating tank 12. The concentrated solution is withdrawn from the concentration chamber through a valve 32 and pumped to the plating tank 12 via a line 34.
The pure water resulting from the vapor compression cycle is withdrawn through valve 36 into the heat exchanger 28 via line 38 and then is returned to rinse tank 18 by line 19.
If desired, the vapor compression system can be used to purify water before it enters the plating cycle. Treatment of the water before it enters the system removes the calcium, magnesium, and other undesired metal ions which are present in every source of water. These metal ions will concentrate in the plating bath as water is lost and settle out as solid salts to form a sludge at the bottom of the tank 12 or remain in the plating solution. In either case, the increasing concentration of undesired metal ions reduces plating efficiency. Eventually the plating solution must be discarded, resulting in a loss of valuable metal ions in the solution discarded, or the sludge must be removed from the plating tank requiring that plating operations be suspended. Accumulation of this sludge would be particularly pronounced where the process cycle is a closed loop as shown. Purification of the incoming fresh water would lessen or eliminate this problem.
FIG. 2 shows a detailed view of one vapor compression apparatus useful in the practice of this invention. The operation of this unit is described with reference to plating rinse water. The system could also be used to treat other liquids such as fruit juices, organic solvents or sea water. A generally cylindrical, vertically oriented housing 39 defines an evaporation chamber 40 which collects vaporized water from the inside of the tubes 54 located at one end of the housing near a compressor 42. The compressor 42 comprises generally a compressor wheel 43, volute 45 and driving means 46. As shown, the driving means is an electric motor 47 mounted on a bracket 48 attached to the housing 39. The motor 47 drives a V-belt drive 49 which in turn rotates the compressor wheel 43. The compressor wheel 43 withdraws vapor from the evaporation chamber maintaining the evaporation chamber at a reduced pressure e.g., 0.5 to 1.5 pisa. As shown, cross-tubes 50 transport compressed vapor from the volute 45 to a condensation-heat exchanger chamber 52.
At the lower end of the housing 39, distal the compressor 42, are a number of concentration chambers (three being shown) 44a, 44b, 44c which are filled with rinse water to be concentrated or incoming fresh water to be purified. Each concentration chamber is fluidly connected to the evaporation chamber 40 by an evaporation surface. As shown, the fluid connection is by means of capillary tubes 54 which extend from the lower portion of their respective concentration chambers and terminate in the plate 56 which forms the floor of the evaporation chamber 40. In general there will be a plurality of tubes extending from each concentration chamber into the evaporation chamber, only one tube per concentration chamber being shown for clarity. The interior walls of the capillary tubes 54 are wet by the liquid being concentrated and provide a large surface area for the formation of water vapor which passes into the evaporation chamber 40.
Sensing means 58a, 58b, and 58c are installed in each concentration chamber to measure the concentration of the remaining liquid. As shown, the various sensing means generate an electrical signal which is fed to a control means 60. The control means 60 activates the three-way valve 32 so that the concentration chambers can be emptied when the liquid in the chambers reaches the desired concentration. In one aspect of this invention the concentration of the remaining liquid is determined by measuring its density. Suitable density measuring devices are known in the liquid measuring art. One general method of density measurement, which could be used in practicing this invention, is displacement measurement using a float. Such devices operate by submerging a float in the liquid to be measured. The float's movement up and down within the liquid generates a continuously variable signal proportional to the density of the surrounding liquid. A full description can be found in Chemical Engineers Handbook, 5th Ed., McGraw-Hill, New York, 1973, especially pages 22-48, and 49, the disclosure of which is incorporated herein by reference.
In general, pumps (not shown) would be associated with the various valves to move the liquid within the system as needed. The chamber would be replenished via valve 30 with more liquid to be concentrated as needed.
A large diameter vertically oriented duct 51 extends longitudinally along the middle of housing 39. Overflow liquid from tubes 54 flows into the duct and down into a reservoir 65.
The liquid in reservoir 65 can in turn be pumped by a pump 66 through a valve 68 to the inlet of valve 30, returning the overflow liquid into the concentration chamber.
OPERATION
In general, as with stills of this type, vapor from the liquid being treated will be generated on an evaporation surface. The vapor generated will be drawn into a compressor, compressed, and the compressed vapor is condensed. Generally the vapor is condensed so that the latent heat of condensation is transferred to the liquid being treated thereby creating more vapor to be compressed.
In greater detail, vapor exiting from the upper end of tubes 54 will enter the evaporation chamber 40, passing over the cross tubes 50. As the vapor passes the cross tubes 50, it will remove some heat from the cross tubes which super heats the vapor and lowers the heat in the compressed vapor. The rising vapor enters a liquid carrier 74 which will remove any remaining liquid droplets entrained in the vapor stream. The barrier is shown as a screen but can be other materials known in the art, one barrier material being porous agglomerated plate.
The vapor, free from liquid, enters the housing surrounding the rotating compressor wheel 43, is accelerated by the wheel and is pushed into the volute 45 where the vapor's velocity decreases and the pressure increases.
The vapor from volute 45 enters the cross tubes 50 and passes through the tubes to a plenum 76 located within the housing. From the plenum, the compressed vapor enters a variable capacity heat exchange chamber. The heat exchange chamber comprises the chamber 52 defined by the plate 56, the upper surface of concentration chamber 44a, and the housing 39. Vapor entering the chamber 52 will be exposed to the exterior walls of the tubes 54 and, being at a higher temperature and pressure than the liquid inside the tubes, will condense to form a liquid. As shown, the chamber 52 contains a quantity of liquid and a vapor filled space 66 above the liquid. The heat transfer to the capillary tubes is different for the vapor filled phase and the liquid phase. By varying the liquid level within the heat exchange chamber 52, the amount of heat transferred to the liquid within the tubes 36 and thus the amount of additional vapor created can be controlled. The heat transfer and thereby the amount of vapor can also be controlled by varying the height of solvent within the tubes, a lower liquid level resulting in a lower heat transfer.
Of course, control of the vapor compression still involves several variables in addition to the liquid level in the chamber 52 or tubes 54. With a given compressor wheel, the amount of liquid withdrawn from the concentration chambers will vary as a function of: compressor wheel speed, inlet geometry and guide vane angle. In general, if the liquid level in the heat exchange chamber is increased, the amount of heat available to evaporate solvent and concentrate liquid is decreased.
The inlet geometry can be changed to vary the compressor's operating capacity. Such variable inlet geometries are well known in the art and a further description is omitted in the interest of brevity.
Because of changes in the distilland or variations in the production process to which this system is attached changes are necessary from time to time. One method of operating the compressor of this system is to increase the compressor capacity, such as by increasing compressor wheel speed until the compressor crosses the surge line and begins to surge. The compressor capacity could then be reduced by a fixed amount, such as by changing compressor speed or inlet geometry, to bring the capacity to the desired point on the efficiency curve. The operating efficiency curves are determined by the variables present in the system each system being individualistic but the operating characteristic curve as easily calculated or emperically determined. Such charts showing efficiency islands as a function of pressure ratio versus flow at a constant impeller tip speed are so well known that a detailed example is omitted. One example of a centrifugal compressor performance chart can be found in Gas Turbines, Sorenson, Ronald Press Co., New York, 1951, especially page 267.
Ordinarily causing a centrifugal compressor wheel to surge would not be a viable means of controlling a process. However, because the compressor wheel is operating at a reduced pressure, the amount of energy applied to the wheel during surge is minimal. Using the surge point of the compressor as a control measurement provides a quick and easy method of determining the operating conditions at a given time since the pressure ratio changes markedly when the compressor surges. Pressure sensing devices are well known in the art and a detailed description is omitted in the interest of brevity. The surge control can be used in combination with the variable heat exchanger to further increase the efficient operating range of the system.
The operating steps detailed above could be performed by a microprocessor which would receive relevant data and determine the operating condition of the system by comparison with a predetermined performance chart. If the system needed correction, the microprocessor would be programmed to drive the system into the surge condition and adjust the compressor capacity as discussed hereinbefore.
Where the liquid in one of the concentration chambers 44a, 44b, and 44c reaches the desired concentration, the sensing means in the associated chamber will activate the control means 60 which in turn activates the valve 32 to empty the concentration chambers. The emptied chamber is refilled and the process continues.
Various modifications and alterations of this invention will become obvious to those skilled in the art without departing from the scope and spirit of this invention. For example, the still of this invention can be used to concentrate fruit juice and for disalinization of water in addition to treating plating rinse water. | A liquid containing a solvent to be evaporated is fed to a concentration chamber which is fluidly connected to an evaporation chamber maintained at a reduced pressure. A vapor compression means withdraws solvent vapor from the evaporation chamber, compresses the vapor and forces the compressed vapor to a liquification chamber. Regulator means responsive to the density of the liquid remaining within the concentration chamber will regulate the rate of solvent evaporation to provide a concentrate suitable for recycling.
A method of operating the still of this invention utilizes the technique of increasing the compressor capacity until the compressor begins to surge and then reducing the capacity a fixed amount to provide the desired efficiency. | 15,358 |
BACKGROUND OF THE INVENTION
The present invention relates to tires for heavy vehicles, such as trucks and buses. More particularly, it relates to the beads of radial carcass tires which have at least one bead wire in each bead and are intended to be mounted on rims defined in accordance with the existing standards and having flanges axially on the outside.
In certain cases, tires for heavy vehicles are called upon to support substantial overloads which produce flexings at the level of the side walls of the tire of an amplitude which is greater, and therefore more disadvantageous, the greater the overload. This problem is also encountered in the case of twin tires when one of the two tires has suffered a loss of pressure, as the result, for instance, of a puncture, and the other tire, which bears the entire load, experiences at its sidewalls flexings which are very disadvantageous for the life of the carcass reinforcement.
Finally, for certain heavy vehicles there is a demand for tires the overall diameter of which is substantially reduced while they retain the profiles and dimensions of rims at present on the market in order to increase the useful load transported; if H represents the height of the tire mounted on its rim, measured on a meridian section between the point of the bead closest to the axis of rotation and the outermost point of the tread of the tire and S the overall width of the tire measured parallel to the axis of rotation, the aspect ratio is defined by H/S.
In the case of aspect ratios less than or equal to 0.6, poor resistance to fatigue of the tire under the cycles imposed by travel is noted; in each side wall of the tire extending between a bead and the belt of the crown, the corresponding portion of the radial carcass is reduced in height and, therefore, each carcass cord undergoes cycles of flexure along small radii of curvature. In operation, upon each revolution of the wheel these cords are subjected to cycles of variation in curvature which are more disadvantageous the smaller this aspect ratio and therefore these radii of curvature.
Various proposals are known which are directed at overcoming excessive fatigue in the sidewall of a tire during the course of travel. Among them, mention may be made of French Patent No. 1,502,689 which discloses that by reinforcing this zone of the tire with, for instance, a layer of rubber stock, the tire is imparted additional rigidity and it is thus possible to decrease the amplitude of the flexing cycles. However, such an arrangement results in an increase in weight and particularly in heating of the sidewalls and therefore in a consumption of energy.
Another proposal disclosed in French Patent Application No. 2,415,016 suggests producing a "depression" in the sidewall of the tire, thus making it possible to reduce the height of the bead and increase the height of the sidewall and therefore to increase the flexibility of the sidewall. This solution makes it possible effectively to increase the life of the sidewalls under strong flexure, but in a manner which is still limited in part due to the fact that the zone of the bead of the tire which is furthest radially to the outside is still forced to flex along the profile of the flange of the rim.
While these two proposals make it possible substantially to increase the life of the sidewall, they still are insufficient in the case of tires of ratios less than or equal to 0.6.
SUMMARY OF THE INVENTION
The object of the present invention is to produce a radial carcass tire mounted on a rim having bead seats which are extended radially and axially to the outside by flanges and the sidewalls of which tire have in inflated state radii of curvature which are substantially greater than those obtained on a tire of the same dimensions made in accordance with the prior art.
Another object is in this way to obtain longer life under the loading cycles caused by travel and under static or dynamic overloads.
The object of the present invention described with reference to the accompanying drawings is a tire for heavy vehicles which is intended to be mounted on a rim J having two bead seats which are extended axially and radially towards the outside by flanges of radius R J , each bead B comprising at least one bead wire 2 of inner radius R T around which a radial carcass armature is anchored by turning-up, characterized by the fact that
(a) the center of gravity 21 of the meridian section of the bead wire 2 is located radially to the outside of the rim flange,
(b) the bead wire 2 has a modulus of elasticity at least equal to 100,000 MPa and its clamping on the rim flange s=(R J -R B )/(R T -R B ) is between 0.1 and 0.9, R B being the radius of the bead of the unmounted tire measured in the plane perpendicular to the axis of rotation and passing through the center of gravity 21 of the cross section of the bead wire 2.
By located radially to the outside of the rim flange, it is to be understood that the center of gravity 21 is located at a distance from the axis of rotation greater than R J and is positioned on a straight line perpendicular to the axis of rotation passing between the point K, the point of connection between the generatrix of the seat of the rim and the flange of the rim, and the point L, point of the furthest axially outward point of the flange of the rim.
In the present invention, in the case of the tire mounted on its rim and inflated to its operating pressure and subjected to its average load of use, the axial component of the forces exerted by the bead on the rim flange resulting from the effects of the inflation pressure and the lateral stresses imposed on the tire along a curve is balanced, for instance, by frictional forces and wedging forces developed between the bead and the rim flange. Adaptation of these forces can be effected by adjusting the value of the clamping of the bead wire 2 and the position of its center of gravity 21 radially to the outside of the rim flange and axially with respect to this same rim flange.
In this position of the bead wire spaced both radially to the outside and axially to the outside with respect to its traditional position, the radius of curvature of the radial reinforcements of the carcass ply is increased, which improves the resistance to fatigue of said reinforcements.
This effect on the radius of curvature of the sidewalls can be further improved if the turn-up of the carcass ply around the bead wire 2 is effected radially towards the inside of the tire.
One advantage of the present invention is the possibility of retaining the rims at present available and in particular of retaining the same diameters of the brake-drum on which the assembly consisting of tire and rim is mounted.
The present invention permits a possible decrease in the outside diameter of the tire in order to obtain a tire having an aspect ratio which is less than or equal to 0.6 with a small section height H while having sidewalls the radii of curvature of which are sufficiently great and assuring a suitable locking of the beads on the rim.
In order to improve, in time, the holding of the tire on the rim with due consideration of the phenomena of flow of the rubber mixes located radially below the bead wire 2, it is advantageous for the portion of the bead B axially to the inside with respect to the bead wire 2 to be extended radially towards the inside by means of an extension 5; said extension may even come into contact with the seat of the rim.
In order to maintain, over the course of time, a force of contact between the portion 5 of the bead B and the rim seat, this extension may be reinforced by various materials, such as, for instance, textile or metal cords arranged annularly or at least a bead wire of any cross section.
In order to assure an effective holding of the bead on the rim even under the effect of thermal stresses generated by the heating of the brake drums as a result of repeated braking, it may be advantageous, while reinforcing the portion 5 of the bead B axially and radially to the inside with respect to the bead wire 2 with, for instance, a bead wire 3 of a modulus of at least 4000 MPa, to arrange one or more connecting plies between the bead wire 3 and the portion of the bead radially to the outside of the flange of the rim.
The role of this ply is to avoid any danger of axial displacement towards the outside of the portion of the bead radially to the outside of the rim flange under the effect of thermal and mechanical stresses.
The cords or cables of each connecting ply are directed in such a manner as to form an angle of between -45° and +45° with respect to the orientation of the carcass reinforcement.
The description which follows, read with reference to the accompanying drawing which shows possible embodiments and is given solely by way of example, will permit of a better understanding of the invention.
DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a view of the transverse half-section of a tire mounted on its rim in accordance with the invention, the axis XX' being the axis of symmetry of the figure;
FIG. 2 is a meridian view of a tire bead, not mounted on a rim, in accordance with the invention;
FIG. 3 is a variant embodiment of the invention in which the portion of the bead furthest axially and radially to the inside comprises a reinforcement bead wire around which there is wound a connecting ply the ends of which are located on opposite sides of the bead wire which is located radially to the outside of the rim flange; and
FIG. 4 is another variant embodiment of the invention in which the two ends of a connecting ply are arranged on the same side with respect to the bead wire which is located radially to the outside of the flange of the rim.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
FIG. 1 shows, in solid lines, the meridian half section of a tire of size 295/50 R 22.5 developed in accordance with the invention, and superimposed on that, drawn in dashed lines, a tire of the same size in accordance with the prior art, these two tires being mounted on the same rim. In this example, the mounting rim J comprises two bead seats, the generatrices of which form an angle of 15°±1° with a line parallel to the axis of rotation, said seats being extended radially and axially towards the outside by flanges in the form of a circular arc of radius 12.7 mm; for said mounting rim the radius R J corresponds to the radial distance between the axis of rotation and a point A of the flange furthest away from the axis of rotation. The point K is the point of connection between the rim seat and the rim flange and the point L is the point of the rim flange furthest axially to the outside.
The tire developed in accordance with the invention comprises a bead wire of "braided" type of interior radius R T , the center of gravity 21 of the section of which is located radially with respect to the axis of rotation at a distance greater than the radius R J of the rim flange and is positioned axially on a straight line perpendicular to the axis of rotation passing between the point K and the point A of the rim flange furthest radially to the outside. A carcass reinforcement 1 of metal cables formed of 12 wires of 18/100 is turned up axially towards the inside around the bead wire 2 to form the turn-up 1', this making it possible to avoid the presence of a point of inflection of the carcass reinforcement above the bead wire 2 and thus to increase the height of the sidewall and therefore the radius of curvature of the sidewall of the inflated tire.
The bead wire 2 of "braided" type has a modulus of elasticity extension equal to 150,000 MPa and its clamping s=(R J -R B )/(R T -R B ) is equal to 0.3 in order to assure the locking of the bead on the rim flange, R B (see FIG. 2) being the radius of the bead of the tire not mounted on the rim measured in the plane which is perpendicular to the axis of rotation and passes through the center of gravity of the cross section of the bead wire 2.
It will be noted that, while having a tire the aspect ratio H/S of which is in this case equal to 0.5, it has been able to retain for the sidewall of the 295/50 R 22.5 tire an average radius of curvature R 2 of the carcass reinforcement which is greater than the average radius R 1 measured on the sidewall of the tire constructed with a bead in accordance with the prior art.
FIG. 2 shows the bead B of a tire developed in accordance with the invention, not mounted on a rim; this bead comprises a carcass ply 1 which is turned up axially towards the inside around a bead wire of "braided" type, positioned in the bead B in such a manner that, once the tire is mounted on the rim, the center of gravity 21 of the cross section of the bead wire 2 is located radially to the outside of the flange of the rim and axially between the two straight lines perpendicular to the axis of rotation and passing through the points K and A. The said bead also comprises a portion 5 of rubber mix which is axially towards the inside with respect to the bead wire 2 and which extends the bead B radially towards the axis of rotation in contact with a portion of the rim flange.
FIG. 3 shows a variant of the invention in which the bead B is extended radially towards the axis of rotation by a portion 5 axially and radially to the inside with respect to the bead wire 2 which is itself positioned radially to the outside of the flange of the rim J; the said portion 5 comes into contact with the seat of the rim J and is reinforced by a bead wire 3 of "braided" type of a modulus equal to 100,000 MPa. Around this bead wire 3 there is wound a connecting ply formed of textile cords, the turn-ups 4 and 4' of which cover, on the two sides, the carcass reinforcement 1 and its turn-up 1'. The end of the turn-up 4' is located at a distance from the axis of rotation greater than the inner radius R T of the bead wire 2 and less than the radius R E of the end of the turn-up 1' of the carcass reinforcement; the end of the turn-up 4 is located at a distance from the axis of rotation greater than the radius of the end of the turn-up 1' of the carcass reinforcement. The cords of this connecting ply are disposed radially.
FIG. 4 shows another tire bead developed in accordance with the invention and mounted on a rim in which the portion 5 of the bead B axially and radially to the inside with respect to the bead wire 2 is extended until coming into contact with the seat of the rim J and comprises a bead wire 3 of "braided" type of a modulus equal to 100,000 MPa, around which there is wound a connecting ply of radially arranged textile cords, the turn-ups 4 and 4' of which are in part superimposed and are both located on the side axially to the outside of the carcass reinforcement. The ends of the turn-ups of the connecting ply are located, with respect to the axis of rotation, at distances greater than the inside radius R T of the bead wire 2 and less than the radius R E of the end of the turn-up 1' of the carcass reinforcement. In order to avoid a discontinuity in resistance to flexure of the zone of the bead located radially to the outside of the bead wire 2, the ends of the turn-ups of the connecting ply are staggered with a minimum stagger of 10 mm between their respective radii.
It should be noted that in the variant tire bead structures shown in FIGS. 3 and 4, the development of the clamping on the flange as a function of time is better controlled due to the fact that a part of the rubber stocks is replaced by at least one ply of a non-flowing material. | A tire structure with radial carcass reinforcement for heavy vehicles and rticularly a tire bead structure which makes it possible to have, on unmodified rims, sidewalls the radii of curvature of which are sufficiently great to avoid premature fatigue of the constituent reinforcement elements of the carcass as a result of the flexing cycles generated by travel. The said tire structure has at least one bead wire (2) which is located radially to the outside of the rim flange (J) and around which the turn-up (1') of the carcass (1) is formed. | 15,970 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of UK Patent Application No. 1504057.9, filed 10 Mar. 2015, the entire contents and substance of which is hereby incorporated by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to an exercise equipment storage apparatus, and in particular a reconfigurable shelving unit for weighted exercise equipment.
[0004] 2. Description of Related Art
[0005] An ever increasing range of exercise equipment is available to gym owners for use by gym users in fitness and strength training. A wider range of exercise equipment enables a gym to provide a wider range of training facilities and to cater for a greater range of customers. Exercise equipment in a gym environment must be stored in an accessible manner such that it is freely yet safely accessible to the gym users. Given the finite space within a gym facility and the requirement to maintain as much free floor space as possible, the amount of exercise equipment a gym may provide is limited by the floor space available and efficiency with which the storage apparatus holds the equipment.
[0006] Given the diversity in the shape and size of modern exercise equipment, storage is typically individually tailored to specific equipment, with dedicated storage being required for each range of equipment. Typically storage is in the form of shelving racks. In order to maintain equipment safely in position on the shelves a retaining element is required to hold, cradle or otherwise restrain the equipment, which differ in size and orientation from equipment to equipment. It is therefore not generally possible to safely store more than one type of equipment on a given storage apparatus. As a result, the requirement to provide a wide range of different storage solutions results in storage inefficiency and limits the variety of equipment that may be provided.
[0007] In addition, should a gym owner decide to replace a range of equipment with an alternative, they must purchase a new rack to hold the alternative range of equipment, adding significantly to the cost of updating their equipment. A further disadvantage, particularly for smaller gyms that require equipment in more limited numbers, is that the number of units of each type of equipment may be significantly less than the number of units which the dedicated storage unit is configured to store. Therefore, the storage unit represents an inefficient use of space and Cost.
[0008] It is therefore desirable to provide an improved exercise storage apparatus which addresses the above described problems and/or which offers improvements generally.
[0009] According to the present invention there is provided an exercise equipment storage apparatus as described in the accompanying claims.
BRIEF SUMMARY OF THE INVENTION
[0010] In an embodiment of the invention there is provided an exercise equipment storage apparatus comprising at least one shelf having a support surface; a support structure arranged to support the at least one shelf; and a plurality of stop members mounted on the support surface defining at least one storage zone for receiving said exercise equipment. The plurality of stop members are reconfigurable to selectively vary the position, size and/or orientation of the at least one storage zone. As such, the storage unit may be reconfigured to house an almost limitless range of exercise equipment. The entire storage unit may be configured to hold a specific range of equipment or configured, and may be reconfigured if that range is replaced with an alternative. The storage unit may alternatively be configured to hold a variety of different equipment on the same unit. This is advantageous for smaller gyms that hold smaller volumes of equipment. It also enables larger gyms to create storage pods with a variety of equipment provided on each pod, enabling the equipment to be distributed at multiple stations around the gym rather than the entire set of each range of equipment being located at a single location.
[0011] The plurality of stop members are retaining elements and preferably cooperate in pairs to form a channel defining the at least one storage zone. A single stop member may cooperate with more than other stop member simultaneously in a paired arrangement. For example a stop member may have stop formations on two sides, with each side pairing with a different stop member. Typically a holding channel is sufficient to retain a piece of exercise equipment, and the channels may cooperate with retaining walls, lips or the like at the front and or rear edges of the shelves to retain the equipment.
[0012] The stop members may comprise an elongate body having a stop surface extending along the length of the body. The shelves are preferably substantially square and the length of the stop members is preferably substantially equal to the length if the sides of the shelves such that in either the lengthwise or transverse orientation the stop members extend substantially across the entire depth or width of the shelf.
[0013] Preferably the stop surface is inclined transversely to the length of the body to define a wedge formation. The wedge formation advantageously enables the stops members to cradle equipment having a rounded lower surface with the wedging action preventing rolling of the equipment in at least the transverse direction.
[0014] The stop members preferably have a vertical rear wall extending along the length of the body on the opposing side to inclined wedge surface. This enables the stop members to be
[0015] The pairs of stop members are preferably arranged parallel to each other with the inclined surfaces facing towards each other such that the storage zones have a substantially convex configuration in the transverse direction relative to the length of the stop members, thereby defining a substantially convex configuration.
[0016] Each shelf preferably includes a plurality of connection points for securing the stop members to the shelf, the connection points being arranged to define a plurality of connection locations with the stop members being reconfigurable by selective securement to different connection locations selected from the plurality of connection locations.
[0017] Each shelf preferably includes a front edge and an orthogonal array of connection points configured to enable the stop members to be secured to the shelf in a parallel arrangement to each other in which the stop members arranged parallel or transverse to the front edge of the shelf. The orthogonal array ensures that the stop members are only able to be secured to the shelf one of a transverse or longitudinal arrangement. Longitudinal is used here to refer to the axis defined front to back of the shelf.
[0018] The plurality of connection points may comprise apertures extending through the shelf for receiving a corresponding connection member. The corresponding connection members may be spigots or lugs extending from the stop members, snap fit connections or threaded connectors provided through the shelf from the underside.
[0019] The corresponding connection member is preferably a threaded fastener, and the stop members may include a plurality of threaded bores having a spacing corresponding to the spacing of the apertures of the shelf such that the threaded bores may be aligned with a selected plurality of connection apertures to receive a corresponding plurality of fasteners extending therethrough. This means of securing the stop members provides a secure connection which is essential where weighted equipment is being stowed, while also enabling the stop members to be removed from reconfiguration using a tool.
[0020] The support structure preferably comprises an upright spine member and a base member, and wherein a plurality of shelves is secured to the spine. The use of a spine enables the shelves to be supported using only a single support member thereby reducing material, parts and cost, as well as maximizing access to the shelves with the spine being located at the rear of the shelves with full access to the front and sides, and providing an aesthetically pleasing design with the shelves having a floating appearance.
[0021] A plurality of connection points are preferably provided along the height of the spine and the plurality of shelves are removably connectable to the plurality of the connection points to enable the height and/or relative spacing of the shelves to be selectively varied. As such equipment of varying heights may be accommodated.
[0022] The spine preferably includes a front face and side walls, with the connection points being formed in the side walls, and wherein each shelf comprises a pair of spaced connection brackets extending from the lower surface configured to locate either side of the spine adjacent the side walls to connect the shelf to the spine. The shelf also preferably includes a retaining wall, lip or ridge at the front and/or rear edges.
[0023] The connection brackets preferably each include a transversely facing connection plate extending downwardly from the lower surface of the shelf having a vertical rear edge and an angled forward edge with the connection plate tapering upwardly in the forward direction towards the lower surface of the shelf. The brackets are secured via connectors inserted through the brackets transversely into the side walls of the spine.
[0024] The connection brackets may each include a flange plate extending downwardly from the rear edge of the shelf, a forwardly extending angular reinforcement plate connecting the base of the flange plate to the lower surface of the shelf, with the transversely facing connection plate being secured to the flange plate and the angular reinforcement member. This arrangement maximizes support of the shelves while minimizing material usage.
[0025] The upper surface of the base is preferably provided with a plurality of connection points corresponding to the connection points of the shelves to enable the stop members to be secured to the base to provide one or more additional storage zones, thereby maximizing the storage efficiency of the apparatus.
[0026] The spine preferably includes a forwardly angled lower section that secures to the base forwardly of the upper section and the base is arranged such that the rear edge of the base is aligned with the rear face of the spine. This ensures that there is a part of the base that extends rearwardly of the connection with the spine for maximum stability, while also ensuring that the apparatus may be placed in flush abutment with a wall with the spine flush with said wall, thereby optimizing the use of space.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] Various features and advantages of the present invention may be more readily understood with reference to the following detailed description taken in conjunction with the accompanying drawings, wherein like reference numerals designate like structural elements, and in which:
[0028] FIG. 1 shows a shelving assembly for weighted exercise equipment according to an embodiment of the invention;
[0029] FIG. 2 shows a shelf of the shelving assembly of FIG. 1 ;
[0030] FIG. 3 shows a view from below of the shelf of FIG. 2 ;
[0031] FIG. 4 shows a stop member of the shelving assembly of FIG. 1 ; and
[0032] FIG. 5 is a view from below of the stop member of FIG. 5 .
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0033] To facilitate an understanding of the principles and features of the various embodiments of the invention, various illustrative embodiments are explained below. Although exemplary embodiments of the invention are explained in detail, it is to be understood that other embodiments are contemplated. Accordingly, it is not intended that the invention is limited in its scope to the details of construction and arrangement of components set forth in the following description or examples. The invention is capable of other embodiments and of being practiced or carried out in various ways. Also, in describing the exemplary embodiments, specific terminology will be resorted to for the sake of clarity.
[0034] It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural references unless the context clearly dictates otherwise. For example, reference to a component is intended also to include composition of a plurality of components. References to a composition containing “a” constituent is intended to include other constituents in addition to the one named.
[0035] Also, in describing the exemplary embodiments, terminology will be resorted to for the sake of clarity. It is intended that each term contemplates its broadest meaning as understood by those skilled in the art and includes all technical equivalents which operate in a similar manner to accomplish a similar purpose.
[0036] Ranges may be expressed herein as from “about” or “approximately” or “substantially” one particular value and/or to “about” or “approximately” or “substantially” another particular value. When such a range is expressed, other exemplary embodiments include from the one particular value and/or to the other particular value.
[0037] Similarly, as used herein, “substantially free” of something, or “substantially pure”, and like characterizations, can include both being “at least substantially free” of something, or “at least substantially pure”, and being “completely free” of something, or “completely pure”.
[0038] By “comprising” or “containing” or “including” is meant that at least the named compound, element, particle, or method step is present in the composition or article or method, but does not exclude the presence of other compounds, materials, particles, method steps, even if the other such compounds, material, particles, method steps have the same function as what is named.
[0039] It is also to be understood that the mention of one or more method steps does not preclude the presence of additional method steps or intervening method steps between those steps expressly identified. Similarly, it is also to be understood that the mention of one or more components in a composition does not preclude the presence of additional components than those expressly identified.
[0040] The materials described as making up the various elements of the invention are intended to be illustrative and not restrictive. Many suitable materials that would perform the same or a similar function as the materials described herein are intended to be embraced within the scope of the invention. Such other materials not described herein can include, but are not limited to, for example, materials that are developed after the time of the development of the invention.
[0041] Referring to FIG. 1 , there is provided a reconfigurable shelving assembly 1 for weighted exercise equipment. The shelving assembly 1 comprises a plurality of shelves 2 supported on a support frame 4 having a base 6 . The support frame 4 comprises a vertical spine member 8 that is preferably formed from rectangular hollow section steel or aluminum. The spine 8 includes an upright and preferably substantially vertical main support section 10 and a lower section 12 that is inclined forwardly.
[0042] The spine 8 includes a front facing wall 14 , side walls 16 and a rear facing wall 18 . In use the front wall 14 is forwardly facing towards the user, and towards the front leading edge of the shelves 2 . The terms ‘forwardly’ and ‘rearwardly’ are relative and are used to refer to a direction towards or away from the leading edge of the shelves and the term ‘sideways’ refers to a direction transverse to the forward and rearward direction. The term ‘upwardly’ and ‘vertically’ are relative to the base 6 and refer to a vertical axis perpendicular to the planar upper face of the base 6 .
[0043] The lower end 12 of the spine 8 is angled forwardly at an elbow 20 located approximately a fifth of the way along the height of the spine 8 . The lower section 12 secures to the base 6 at a connection point 24 which has a forward location relative to the main support section 10 . The base 6 forms a foot for supporting the spine 8 and shelves 2 such that the support assembly 1 is free standing. The forwardly inclined arrangement of the lower section 12 of the spine 8 allows a rear portion 22 of the base 6 to extend rearwardly of the connection point 24 with the lower section 12 such that the rear edge 26 of the base 6 is aligned with the rear face 18 of the spine 8 . This enables the support assembly 1 to be located flush against a wall with the spine 8 substantially abutting the wall without interference from the base 6 . The base 6 comprises a planar support plate which preferably extends forwardly at its front edge 28 a greater distance than the front edge of the shelves 2 to maximize stability.
[0044] The shelves 2 are preferably formed from folded sheet metal such as steel or aluminum. As shown in FIG. 2 each shelf 2 includes a ridge 30 along the front edge 32 defining a forward retaining wall. The ridge 30 is formed by a v-shaped fold including an inclined surface 34 forming a wedge arrangement on the inner side of the ridge 30 and a vertical flange section 36 defining a flat front facing wall to the shelf. At the rear edge 40 a rearwardly inclined wall 42 is also formed to provide a wedge arrangement at the rear edge. The front wedge 34 and rear wedge 42 combine to define a concave profile across the shelf 2 along the longitudinal axis defined front to back of the shelf 2 . A flat section 44 is provided rearwardly of the wedge 42 , and a vertical flange section 46 extends vertically downwards at the rear edge of the shelf 2 .
[0045] An array of apertures 43 is formed through the main planar section 45 of the shelf 2 . The apertures 43 are arranged in an orthogonal array with rows extending transversely and longitudinally across the plate. In the embodiment shown in FIG. 2 , four transversely extending rows are provided that are evenly spaced in the longitudinal direction. The apertures 43 along these rows also form longitudinally extending rows. Nine apertures are provided across the shelf 2 in the transverse direction such that nine longitudinal rows are defined.
[0046] As shown in FIG. 3 , a channel 48 is defined midway along the rear flange plate 46 , with a corresponding cut away 50 being formed in the flat section 44 . The channel 48 has a width corresponding to the width of the spine 8 with the spine 8 being received in the channel 48 to secure the shelf 2 to the spine 8 . Either side of the channel 48 are provide longitudinally extending connection plates 52 having a plurality of apertures 54 arranged vertically adjacent the rear edge of the plates 52 . The size and spacing of the apertures 42 corresponds to a plurality of connection apertures 56 formed along the side walls of the spine 8 . The apertures 54 of the shelf 2 are aligned with the apertures 56 of the spine 8 and threaded fasteners or any other suitable connection means are passed through the aligned apertures to secure the shelf 2 to the spine 8 at a selected and variable height. The apertures 56 of the spine may include an inner thread formed by any suitable means to enable a threaded fastener to be screwed directly into the spine 8 . The connection plates 52 taper upwardly in the forward direction and provide bracing for the shelf in connection with rear flange plate 46 . Forwardly extending upwardly inclined plates 58 extend from the flange plate to the shelf 2 to provide further support, with the inclined plates being connected to the connection plates 52 .
[0047] As shown in FIG. 4 , a stop member 60 comprises an elongate body 62 having an inclined stop surface 64 extending along its length. The stop member 60 includes a substantially vertical rear wall 66 , an upper edge 68 , a front edge 70 and end walls 72 . The stop surface 64 is inclined downwardly from the upper edge 68 to the front edge 70 in the transverse direction relative to the length of the body 62 , such that when viewed from the end the stop member 60 has a substantially right angled triangular cross sectional shape providing the stop member 60 with a wedged configuration. The stop surface 64 includes a textured grip surface having an integrally molded raised waveform pattern which increases the friction coefficient of the surface, thereby improving grip. Other surface texturing may be utilized to improve grip and/or the surface may be provided with a resilient coating or covering such as rubber to improve grip. A plurality of scalloped sections 74 are formed along the upper edge 68 having a substantially semi-circular shape to allow these sections to cradle a cylindrical bar such as a weight bar or a cylindrical handle or other component of an exercise device when supported on the upper edge 68 of two or more stop members 60 . A recess 76 is formed centrally along the stop surface 64 and front edge 70 that enables the wedged stop member 60 to more effectively cradle a spherical exercise apparatus such as a medicine ball. The recess 76 includes inwardly inclined front edge sections 78 and a section of the stop surface that is inclined downwardly at a greater angle than the rest of the surface.
[0048] Longitudinal stops 79 are provided proximate either end of the stop surface 64 . The longitudinal stops 79 are preferably rubber or plastic blocks arranged to prevent apparatus rolling longitudinally past the ends of the stop member 60 . The blocks 79 are preferably removable and include spigots 81 extending from their lower surface that are inserted into corresponding recesses in the stop surface 64 to removably secure them thereto.
[0049] A shown in FIG. 5 , the lower surface 82 of the stop member 60 includes a pair of attachment elements 84 for securing the stop member to a shelf 2 . The attachment members comprise cylindrical elements or bosses each having a threaded inner bore for receiving a corresponding treaded fastener. The body 62 of the wedged stop member 60 is preferably hollow as shown, with a plurality of reinforcing walls 86 supporting the threaded bosses 84 , and the stop surface 64 .
[0050] Referring again to FIG. 1 , the stop members 60 are securable to the support surface 45 of the shelves 2 in a multitude of different configurations by aligning the attachment elements 84 with two correspondingly spaced apertures 43 . The array of apertures 43 is arranged such that the spacing of the apertures 43 corresponds to the spacing of the attachment elements 84 , with the spacing of the attachment elements 84 being a multiple of the spacing of the apertures 43 . In the shelf shown in FIG. 2 the spacing of the front and rear transverse rows of aperture 43 are spaced apart equal to the spacing of the attachment elements 84 . The stop members are therefore only locatable lengthwise in a single lengthwise position when oriented lengthwise, front to back, but are locatable in this longitudinal position at multiple transverse locations width wise by connection to corresponding pairs of apertures 43 along the front and rear rows of apertures 43 . The spacing of the apertures along the transverse rows is such the outermost apertures 43 at the ends of the rows are spaced apart equal to the spacing of the attachment elements 84 , such that when oriented transversely, the stop members 60 are only locatable width wise in a single width wise position but are locatable in this orientation at multiple locations lengthwise by connection to corresponding pairs of apertures 43 the longitudinal rows of apertures 43 .
[0051] The stop members 60 may also be oriented transversely and secured in position in a similar manner by alignment of the attachment elements 84 with a correspondingly spaced pair of connection apertures 43 at the required location. As shown in FIG. 1 , the vertical back walls 62 of the stop members 60 allows them to be abutted back to back. To enable this the attachment elements 84 are located centrally in the transverse direction and the apertures 43 are spaced apart a distance equal to the width of the stop elements 60 , with the distance between the attachment elements of two stop elements back to back being equal to the spacing of the aperture 43 and equal to the width of one stop member 60 .
[0052] Whilst endeavoring in the foregoing specification to draw attention to those features of the invention believed to be of particular importance it should be understood that the Applicant claims protection in respect of any patentable feature or combination of features hereinbefore referred to and/or shown in the drawings whether or not particular emphasis has been placed thereon. | An exercise equipment storage apparatus having a number of shelves, each having a support surface. A support structure in the form of a spine is arranged to support the shelves. A plurality of stop members are mounted on the support surface. The stop members define at least one storage zone for receiving the exercise equipment. The plurality of stop members are reconfigurable to selectively vary the position, size and/or orientation of the at least one storage zone. As such, the storage unit may be reconfigured to house an almost limitless range of exercise equipment. | 25,915 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The instant disclosure relates to a bidirectional wireless charging device; in particular, to a bidirectional wireless charging device with an integrated transceiver chip.
2. Description of Related Art
With the technology well developed, there are many kinds of personal mobile devices and wearable devices which connect with the Internet, provide people a so-called mobile life, and thus increase the convenience in our daily lives. However, the requirement of electric power for using these electric products also gradually increases. For solving this problem, there is a wireless charging device developed currently. The wireless charging device can be generally categorized as two kinds, wherein one is the wireless charging device using the Electromagnetic Induction Technology and another is the wireless charging device using the Electromagnetic Resonance Technology. Particularly, the wireless charging device using the Electromagnetic Induction Technology is more common. The advantage of the wireless charging device is that the electric device and the wireless charging device do not need wires to have a connection.
In the prior art, one wireless charging device merely has a signal direction wireless charging function. For example, the wireless charging device as a powering end can merely provide electric power, and the wireless charging device as a charging end can merely receive electric power. Generally, there is not the wireless charging device which can provide electric power outdoors, which means that the user's portable electric device may not be used anywhere anytime. For example, when the power of the wireless charging device runs out and the wearable device, such as a smart watch, has an urgent request for charging, if there was an electric device having sufficient power which could charge the smart watch, the above problem could be solved.
Therefore, in the prior art, there has been a kind of bidirectional wireless charging device developed. The bidirectional wireless charging device has a power providing function and a power receiving function. Thus, the bidirectional wireless charging device can be a powering end or a charging end under different circumstances.
However, the traditional bidirectional wireless charging device must have an emitter chip and its corresponding circuit (such as a control circuit, a modulation circuit, a power stage circuit and the like), and have a transceiver chip and its corresponding circuit (such as a control circuit, a modulation circuit, a power stage circuit, a rectifying circuit and the like). In other words, to realize the bidirectional wireless charging function, the area of inner circuit of the bidirectional wireless charging and the cost dramatically increase.
SUMMARY OF THE INVENTION
The instant disclosure provides a bidirectional wireless charging device. The bidirectional wireless charging device comprises a transceiver chip receiving a switch signal. The transceiver chip comprises a power stage circuit and a control module. The power stage circuit is electrically connected to a coil, and outputs a voltage to the coil or receives an induced voltage from the coil. The control module is electrically connected to the power stage circuit, and correspondingly makes the transceiver chip turn into a power mode or a charging mode according to the switch signal. The transceiver chip provides the voltage to the coil when the switch signal indicates that the transceiver chip turns into the power mode. The transceiver chip receives the induced voltage from the coil and charges a power storage unit of the bidirectional wireless charging device, when the switch signal indicates that the transceiver chip turns into the charging mode.
The instant disclosure further provides a bidirectional wireless charging system. The bidirectional wireless charging system comprises at least two bidirectional wireless charging devices. Each bidirectional wireless charging device comprises a transceiver chip receiving a switch signal. The transceiver chip comprises a first bidirectional wireless charging device and a second bidirectional wireless charging device. The first bidirectional wireless charging device and the second bidirectional wireless charging device respectively comprise a power stage circuit and a control module. The power stage circuit is electrically connected to a coil, and outputs a voltage to the coil or receives an induced voltage from the coil. The control module is electrically connected to the power stage circuit, and correspondingly makes the transceiver chip turn into a power mode or a charging mode according to the switch signal. The first bidirectional wireless charging device and the second bidirectional wireless charging device are either a charging end and a powering end according to the switch signal. When the first bidirectional wireless charging device is the powering end, the transceiver chip of the first bidirectional wireless charging device turns into the power mode and provides the voltage to the coil so as to make the first bidirectional wireless charging device provide a pulse width modulated signal to the second bidirectional wireless charging device. The pulse width modulated signal includes an electromagnetic energy. When the second bidirectional wireless charging device is the charging end, the transceiver chip of the second bidirectional wireless charging device turns into the charging mode, receives the induced voltage from the coil, and charges a power storage unit of the second bidirectional wireless charging device.
To sum up, the bidirectional wireless charging device provided by the instant disclosure can used as a powering end or a charging end to improve the convenience of the bidirectional wireless charging device. Moreover, compared with the traditional bidirectional wireless charging device, the transceiver chip of the bidirectional wireless charging device provided by the instant disclosure integrates the power mode operation module and the charging mode operation module into a single chip. Thereby, merely one control module and one power stage circuit are needed for the instant disclosure to provide the bidirectional wireless charging function, which effectively shrinks the circuit area, decreases the cost and also reduces the system complexity.
For further understanding of the instant disclosure, reference is made to the following detailed description illustrating the embodiments and examples of the instant disclosure. The description is only for illustrating the instant disclosure, not for limiting the scope of the claim.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:
FIG. 1 shows a schematic diagram of a bidirectional wireless charging system of one embodiment of the instant disclosure;
FIG. 2 shows a block diagram of a bidirectional wireless charging device of one embodiment of the instant disclosure;
FIG. 3A a schematic diagram of a bidirectional wireless charging device of one embodiment of the instant disclosure;
FIG. 3B a schematic diagram of a bidirectional wireless charging device of another embodiment of the instant disclosure;
FIG. 4 shows a schematic diagram of a bidirectional wireless charging device of one embodiment of the instant disclosure in the power mode;
FIG. 5 shows a schematic diagram of a bidirectional wireless charging device of one embodiment of the instant disclosure in the charging mode;
FIG. 6 shows a flow chart of a bidirectional wireless charging device of one embodiment of the instant disclosure in the power mode; and
FIG. 7 shows a flow chart of a bidirectional wireless charging device of one embodiment of the instant disclosure in the charging mode.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
The aforementioned illustrations and following detailed descriptions are exemplary for the purpose of further explaining the scope of the instant disclosure. Other objectives and advantages related to the instant disclosure will be illustrated in the subsequent descriptions and appended drawings. In the drawings, the size and relative sizes of layers and regions may be exaggerated for clarity.
It will be understood that, although the terms first, second, third, and the like, may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only to distinguish one element, component, region, layer or section from another region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the instant disclosure. As used herein, the term “and/or” includes any and all combinations of one or more of the associated listed items.
Please refer to FIG. 1 , FIG. 1 shows a schematic diagram of a bidirectional wireless charging system of one embodiment of the instant disclosure. The bidirectional wireless charging system comprises at least two bidirectional wireless charging devices. In this embodiment, the bidirectional wireless charging system comprises a first bidirectional wireless charging device 1 A, a second bidirectional wireless charging device 1 B and a third bidirectional wireless charging device 1 C. It is to be noted that FIG. 1 is merely used to describe the bidirectional wireless charging system of one embodiment of the instant disclosure but does not limit the instant disclosure. In other embodiments, the bidirectional wireless charging system can merely comprise two bidirectional wireless charging devices or comprise more than two bidirectional wireless charging devices.
The first bidirectional wireless charging device 1 A, the second bidirectional wireless charging device 1 B and the third bidirectional wireless charging device 1 C can be a mobile phone, a tablet computer, a laptop, a wireless charger, a smart watch, a set-top box or other electric products having a wireless charging function. For an easy instruction and understanding of the instant disclosure, in the following description, the first bidirectional wireless charging device 1 A may be a mobile phone, the second bidirectional wireless charging device 1 B may be a wireless charger and the third bidirectional wireless charging device 1 C may be a smart watch. In addition, the first bidirectional wireless charging device 1 A, the second bidirectional wireless charging device 1 B and the third bidirectional wireless charging device 1 C are operated according to the Electromagnetic Induction Technology. However, it is not limited herein. The first bidirectional wireless charging device 1 A, the second bidirectional wireless charging device 1 B and the third bidirectional wireless charging device 1 C can also be operated according to the Electromagnetic Resonance Technology.
The second bidirectional wireless charging device 1 B may often be provided with commercial power and thus maintain sufficient power. When the first bidirectional wireless charging device 1 A has insufficient power, the user can operate the first bidirectional wireless charging device 1 A to send a switch signal to the second bidirectional wireless charging device 1 B. For example, the switch signal is an analogue signal indicating that the bidirectional wireless charging device turns into a power mode or a charging mode. For instance, the bidirectional wireless charging device receiving a high-level switch signal would turn into the power mode, and he bidirectional wireless charging device receiving a low-level switch signal would turn into the charging mode. After receiving the high-level switch signal, the second bidirectional wireless charging device 1 B turns into the power mode and starts to charge the first bidirectional wireless charging device 1 A.
In another case, when the stored power of the first bidirectional wireless charging device 1 A is insufficient to drive the first bidirectional wireless charging device 1 A, the user can also operate the second bidirectional wireless charging device 1 B to send a low-level switch signal to the first bidirectional wireless charging device 1 A. The switch signal has energy, so the first bidirectional wireless charging device 1 A can be turned on by the energy of the switch signal. After that, the first bidirectional wireless charging device 1 A would reply the second bidirectional wireless charging device 1 B with a high-level switch signal. After receiving the high-level switch signal, the second bidirectional wireless charging device 1 B starts to charge the first bidirectional wireless charging device 1 A.
When the stored power of the first bidirectional wireless charging device 1 A reaches a predetermined value (such as 90% of the maximum stored power of the first bidirectional wireless charging device 1 A), the first bidirectional wireless charging device 1 A sends a status signal to the second bidirectional wireless charging device 1 B, so that the second bidirectional wireless charging device 1 B ends the power mode and thus stops charging the first bidirectional wireless charging device 1 A.
Sometimes the user may bring the first bidirectional wireless charging device 1 A, the second bidirectional wireless charging device 1 B and the third bidirectional wireless charging device 1 C outside, and in this case the second bidirectional wireless charging device 1 B can't be provided with commercial power and can't maintain sufficient power. When the second bidirectional wireless charging device 1 B has insufficient power, the second bidirectional wireless charging device 1 B can't charge the third bidirectional wireless charging device 1 C. There may be a more urgent demand for using the third bidirectional wireless charging device 1 C, so the user would try not to run out the power of the third bidirectional wireless charging device 1 C. At this moment, the user can operate the third bidirectional wireless charging device 1 C to send a switch signal to the first bidirectional wireless charging device 1 A, so that the first bidirectional wireless charging device 1 A would turn into the power mode and start to charge the third bidirectional wireless charging device 1 C.
In other words, the first bidirectional wireless charging device 1 A, the second bidirectional wireless charging device 1 B and the third bidirectional wireless charging device 1 C provided in this embodiment can be used as a charging end or a powering end, so as to increase the convenience of the bidirectional wireless charging system.
In addition, the switch signal can be a Pulse Width Modulation signal (PWM signal) sent by a coil; however, it is not limited herein. For example, in other embodiments, the bidirectional wireless charging device 1 can send a switch signal wirelessly via a wireless transmission unit (not shown in FIG. 1 ).
There is further instruction for a structure of the bidirectional wireless charging device in the following description. Please refer to FIG. 2 , FIG. 2 shows a block diagram of a bidirectional wireless charging device of one embodiment of the instant disclosure. The bidirectional wireless charging device 1 can be one of the above mentioned first bidirectional wireless charging device, second bidirectional wireless charging device 1 B and third bidirectional wireless charging device 1 C. For a need to instruct easily, they are described as the bidirectional wireless charging device 1 in the following description.
The bidirectional wireless charging device 1 comprises a transceiver chip 10 , a coil 11 , a power processing unit 12 and a power storage unit 13 . The coil 11 is electrically connected to the transceiver chip 10 . The transceiver chip is electrically connected to the power processing unit 12 and the power storage unit 13 . The power processing unit 12 is electrically connected to the power storage unit 13 .
The coil 11 can be a cable coil or other inductor that can generate an induced voltage corresponding to a variable electromagnetic field. When the bidirectional wireless charging device 1 is used as a powering end, the coil 11 can convert the voltage into a PWM signal and send the PWM signal out. The PWM signal includes an electromagnetic energy, so a charging end can charge with the received electromagnetic energy. When the bidirectional wireless charging device is used as a charging end, the coil 11 can sense the PWM signal and convert the electromagnetic energy of the PWM signal into an induced voltage.
The transceiver chip 10 receives the switch signal and correspondingly controls and makes the bidirectional wireless charging device 1 turn into the power mode or the charging mode. Moreover, when the bidirectional wireless charging device 1 is used as a powering end, the transceiver chip 10 receives the voltage from the power processing unit 12 and the power storage unit 13 , and provides the voltage to the coil 11 so that the coil 11 generates a PWM signal. When the bidirectional wireless charging device 1 is used as a charging end, the transceiver chip 10 receives an induced voltage generated by the coil 11 , and rectifies and regulates the induced voltage to generate a regulated voltage.
The power processing unit 12 manages the stored power of the bidirectional wireless charging device 1 . For example, the power processing unit 12 determines when to transmit the regulated voltage outputted by the transceiver chip 10 to the power storage unit 13 , or makes the power storage unit 13 provide power to the transceiver chip 11 .
The power storage unit 13 is used to store power, for example, the battery of the bidirectional wireless charging device 1 or other power storage devices, such as a capacitor.
For further instruction, please refer to FIG. 3A . FIG. 3A is a schematic diagram of a bidirectional wireless charging device of one embodiment of the instant disclosure. As described in the above embodiment, the bidirectional wireless charging device 1 comprises a transceiver chip 10 , a coil 11 , a power processing unit 12 and a power storage unit 13 . The relationship of connection between the transceiver chip 10 , the coil 11 , the power processing unit 12 and the power storage unit 13 for this embodiment can be referred to the description in the previous embodiment, and thus the redundant information is not repeated. The following description is merely for the difference between this embodiment and the previous embodiment.
The transceiver chip 10 further comprises a control module 101 , a power stage circuit 102 , a charging mode operation module 104 and a power mode operation module 103 . The control module 101 is electrically connected to the power stage circuit 102 . The power stage circuit 102 is electrically connected to the coil 11 . The charging mode operation module 104 is electrically connected to the control module 101 and the coil 11 . The power mode operation module 103 is electrically connected to the control module 101 and the coil 11 .
In conjunction with FIG. 3 a and FIG. 3B , FIG. 3B is a schematic diagram of a bidirectional wireless charging device of another embodiment of the instant disclosure. The transceiver chip 10 of the bidirectional wireless charging device 1 also comprises a control module 101 , a power stage circuit 102 , a charging mode operation module 104 and a power mode operation module 103 . The following is further instruction about the structure and function of the transceiver chip 10 .
The control module 101 comprises a control unit 1010 . The control unit 1010 is electrically connected to the power stage circuit 102 . The control unit 1010 controls and adjusts the voltage output by the power stage circuit 102 .
The power stage circuit 102 comprises a power switch, a pulse width modulation circuit, an isolated high-frequency transformer, a rectifying circuit and an output filter (not shown in FIG. 3B ). The rectifying circuit can be, for example, a half-bridge rectifying circuit or a full-bridge rectifying circuit, to generate a rectified voltage.
When the bidirectional wireless charging device 1 is used as a power end, the power stage circuit 102 drives the power switch and provides a voltage to the coil 11 , so that the coil 11 is driven to have a resonance and output a PWM signal. When the bidirectional wireless charging device 1 is used as a charging end, the power stage circuit 102 receives an induced voltage from the coil 11 and generates a rectified voltage. The detailed structure and the working mechanism of the power stage circuit 102 would be able to be comprehended by one skilled in the art and further descriptions are therefore omitted.
The power mode operation module 103 comprises a demodulation unit 1030 electrically connected to the control unit 1010 and the coil 11 . The demodulation unit 1030 receives a PWM signal PWM′ output by another bidirectional wireless charging device which is used as a charging end via the coil 11 , and demodulates the received PWM signal PWM′. The PWM signal PWM′ includes a status message sent from the charging end. In detail, the status message comprises a quantity of the charging end (for example, the currently stored electric quantity of the charging end), an energy adjusting request, an energy maintaining request, a cut-off supply request or the like. The demodulation unit 1030 filters the high-frequency band out from PWM signal PWM′, maintains the amplitude, and uses the amplitude size as a status message sent by the charging end. After that, the demodulation unit 1030 outputs the demodulated status message to the control unit 1010 , so that the control unit 1010 correspondingly controls the voltage output by the power stage circuit 102 according to the demodulated status message.
For example, when the status message includes an energy adjusting request, the control unit 1010 would correspondingly adjust the voltage output by the power stage circuit 102 according to the currently stored power of the charging end. When the status message includes an energy maintaining request, the control unit 1010 would make the power stage circuit 102 maintain the provided voltage.
The charging mode operation module 104 comprises a voltage regulating unit 1040 and a modulation unit 1041 . The voltage regulating unit 1040 is electrically connected to the control unit 1010 , the power stage circuit 102 and the power processing unit 12 . The modulation unit 1041 is electrically connected to the control unit 1010 and the coil 11 . The voltage regulating unit 1040 receives the rectified voltage output by the power stage circuit 102 , regulates the rectified voltage and outputs the regulated voltage to charge the power storage unit 13 of the bidirectional wireless charging device 1 . The modulation unit 1041 is controlled by the control unit 1010 . The control unit 1010 controls and makes the modulation unit 1041 generate a PWM signal including a status message according to the regulated voltage value and the power currently stored in the bidirectional wireless charging device.
Please refer to FIG. 4 . FIG. 4 shows a schematic diagram of a bidirectional wireless charging device of one embodiment of the instant disclosure in the power mode. When another bidirectional wireless charging device 1 ′ (not shown in FIG. 4 , such as the wireless charging device 1 ′ in FIG. 5 ) has insufficient power (for example, the left power of the bidirectional wireless charging device 1 ′ is less than 20% of the maximum stored power but more than the minimum stored power), the user can operate the bidirectional wireless charging device 1 ′ to send a switch signal, such as a high-level switch signal. After receiving the switch signal, the bidirectional wireless charging device 1 turns into the power mode and becomes a powering end to start to provide power to the bidirectional wireless charging device V. In addition, in this embodiment, the high-level switch signal corresponds to the power mode but it is not limited herein. That is, in other embodiments, the low-level switch signal can also be set to correspond to the power mode.
Further, when the switching unit (not shown in FIG. 4 ) of the control module 101 receives the high-level switch signal, the switching unit makes the circuit path corresponding to the power mode operation module 103 turn on (shown as the circuit path connected by the real line in FIG. 4 ), and makes the circuit path corresponding to the charging mode operation module 103 turn off (shown as the circuit path connected by the dash line in FIG. 4 .). The switching unit may be, for example, a multiplexer or a Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) switch, so as to switch the corresponding circuit path according to the switch signal.
After the bidirectional wireless charging device 1 turns into the power mode, the power processing unit 12 controls the power storage unit 13 to provide power to the power stage circuit 102 . After that, the control unit 1010 of the control module 101 controls the power stage circuit 102 to output a voltage to the coil 11 so as to drive the coil to have the resonance and to output a PWM signal having the electromagnetic energy. As the charging end, the coil 11 of the bidirectional wireless charging device 1 ′ generates an induced voltage via the electromagnetic induction and start to charge.
When the stored power of the bidirectional wireless charging device 1 ′ reaches a predetermined value, the bidirectional wireless charging device 1 ′ would output a PWM signal including a cut-off supply request. After the demodulation unit 1030 of the power mode operation module 103 of the bidirectional wireless charging device 1 receives a PWM signal PWM′ via the coil 11 , it would demodulate the PWM signal PWM′ and output a demodulated status message. The control unit 1010 receives the status message and correspondingly controls the output power of the power stage circuit 102 according to the status message. For example, when the bidirectional wireless charging device 1 receives the status message indicating that the stored power of the bidirectional wireless charging device 1 ′ reaches a predetermined value (such as 90% of the maximum stored power of the bidirectional wireless charging device 1 ′, but it is not limited herein), the control unit 1010 of the bidirectional wireless charging device 1 makes the power stage circuit 102 stop charging the bidirectional wireless charging device 1 ′.
Please refer to FIG. 5 . FIG. 5 shows a schematic diagram of a bidirectional wireless charging device of one embodiment of the instant disclosure in the charging mode. Different from the embodiment shown in FIG. 4 , the bidirectional wireless charging device 1 ′ shown in FIG. 5 is used as the charging end. In addition, the bidirectional wireless charging device 1 shown in FIG. 4 and the bidirectional wireless charging device 1 ′ shown in FIG. 5 have the same structure but different operation modes.
Further, when the user tends to charge the bidirectional wireless charging device 1 ′, the user can make the bidirectional wireless charging device 1 ′ turn into the charging mode. At this moment, the switching signal generating unit (not shown in FIG. 5 ) of the bidirectional wireless charging device 1 ′ would generate a high-level switch signal and a low-level switch signal. The high-level switch signal is sent to the bidirectional wireless charging device 1 (not shown in FIG. 5 , such as the wireless charging device 1 ), so that the bidirectional wireless charging device 1 turns into the power mode. The low-level switch signal is sent to the control module 101 ′ of the bidirectional wireless charging device 1 ′, so that the bidirectional wireless charging device 1 ′ turns into the power mode.
After the switching unit (not shown in FIG. 5 ) of the control module 101 ′ receives the switch signal, the switching unit makes the circuit corresponding to the charging mode operation module 104 ′ turn on (shown as the circuit path connected by the real line in FIG. 5 ), but makes the circuit corresponding to the powering mode operation module 103 ′ turn off (shown as the circuit path connected by the dotted line in FIG. 5 ). As mentioned above, the switching unit, such as a multiplexer or a MOSFET switch, is configured to correspondingly switch the circuit paths according to the switch signal.
The coil 11 ′ receives the PWM signal from the bidirectional wireless charging device 1 , and converts the electromagnetic energy of the PWM signal into an induced voltage. The power stage circuit receives and rectifies the induced voltage, and outputs a rectified voltage.
The voltage regulating unit 1040 ′ of the charging mode operation module 104 ′ receives and regulates the rectified voltage, and generates a regulated voltage. After that, the voltage regulating unit 1040 ′ outputs the regulated voltage to the control unit 1010 ′, so as to provide power for the operation of the bidirectional wireless charging device V. Moreover, the voltage regulating unit 1040 ′ outputs the regulated voltage to the power processing unit 12 ′, and the power processing unit 12 ′ uses the regulated voltage to charge the power storage unit 13 ′.
After receiving the regulated voltage, the control unit 1010 ′ makes the modulation unit 1041 ′ change the voltage amplitude of the coil 11 according to the regulated voltage value and the currently stored power of the bidirectional wireless charging device 1 ′, so that the coil 11 ′ generates a PWM signal PWM′ including a status message for informing the powering end about the current electric quantity of the bidirectional wireless charging device 1 ′, an energy adjusting request, an energy maintaining request or a cut-off supply request.
The steps for the bidirectional wireless charging device 1 ′ to generate a PWM signal PWM′ are as follows. After receiving the regulated voltage, the control unit 1010 ′ determines whether the power provided from the power storage unit 13 ′ to the bidirectional wireless charging device 1 ′ is within a normal range. If the power provided by the power storage unit 13 ′ is not within the normal range, it means that the power currently stored in the power storage unit is insufficient to support and maintain the operation of the bidirectional wireless charging device V. At this moment, the control unit 1010 ′ makes the modulation unit 1041 ′ change the voltage amplitude of the coil 11 ′, so as to generate a PWM signal PWM′ including an energy adjusting request or an energy maintaining request. If the power provided by the power storage unit 13 ′ is within the normal range, the control unit 1010 ′ further detects whether the power stored in the power storage unit 13 ′ reaches a predetermined value. When the control unit 1010 ′ determines that the power stored in the power storage unit 13 ′ reaches the predetermined value, the control unit 1010 ′ makes the modulation unit 1041 ′ generate a PWM signal PWM′ including a cut-off supply signal.
For example, when the power provided by the power storage unit 13 ′ is not within the normal range, the control unit 1010 ′ makes the modulation unit 1041 ′ generate a PWM signal PWM′ including an energy adjusting request, so as to request the powering end to provide a PWM signal PWM having more energy.
When the power provided by the power storage unit 13 ′ is within the normal range and the power stored in the power storage unit 13 ′ has not reached the predetermined value (such as 90% of the maximum stored power of the bidirectional wireless charging device 1 ′), the control unit 1010 ′ makes the modulation unit 1041 ′ generate a PWM signal PWM′ including an energy adjusting request, so as to request the powering end to output a PWM signal PWM having more energy. In another case, the control unit 1010 ′ can also makes the modulation unit 1041 ′ generate a PWM signal PWM′ including an energy maintaining request, so as to make the powering end keep outputting the current PWM signal PWM.
When the power provided by the power storage unit 13 ′ is within the normal range and the control unit 1010 ′ determines that the power stored in the power storage unit 13 ′ reaches the predetermined value, the control unit 1010 ′ makes the modulation unit 1041 ′ generate a PWM signal PWM′ including a cut-off supply signal, so as to make the powering end stop charging the bidirectional wireless charging device 1 ′.
In addition, the above embodiment is an example for describing the application of the instant disclosure, but it is not limited herein. The user can set the normal range of power provided by the power storage unit 13 ′ and set the predetermined value of power stored in the power storage unit 13 ′ based on need.
In other embodiments, the control unit 1010 ′ is also configured to make the modulation unit 1041 ′ generate a PWM signal PWM including a status message once every time interval, so as to inform the powering end of the current electric quantity of the bidirectional wireless charging device 1 ′, an energy adjusting request, or an energy maintaining request. Thereby, the powering end can dynamically adjust the electromagnetic energy provided to the bidirectional wireless charging device 1 ′.
For instance, when the status message output by the bidirectional wireless charging device 1 ′ indicates that the currently stored power of the bidirectional wireless charging device 1 ′ is less than 70% of the maximum stored power, the powering end would output a PWM signal PWM with more energy. When the status message output by the bidirectional wireless charging device 1 ′ indicates that the currently stored power of the bidirectional wireless charging device 1 ′ is about 70%-90% of the maximum stored power, the powering end would output a PWM signal PWM with less energy. When the status message output by the bidirectional wireless charging device 1 ′ indicates that the currently stored power of the bidirectional wireless charging device 1 ′ is more than 90% of the maximum stored power, the powering end would stop charging the bidirectional wireless charging device 1 ′. In addition, the above embodiment is an example for describing the application of the instant disclosure, but it is not limited herein. The user can set how the bidirectional wireless charging device 1 and bidirectional wireless charging device 1 ′ dynamically adjust the electromagnetic energy based on needs.
In this embodiment, the transceiver chip 10 of the bidirectional wireless charging device 1 merely comprises one power mode operation module 103 and one charging mode operation module 104 . In other embodiments, the transceiver chip 10 can also comprise a plurality of coils 11 , a plurality of power mode operation modules 103 and a plurality of charging mode operation modules 104 . The power mode operation modules 103 are electrically connected to the control module 101 and the corresponding coil 11 respectively, and the charging mode operation modules 104 are electrically connected to the control module 101 , the corresponding coils and the power stage circuit 102 respectively. Thereby, the bidirectional wireless charging device 1 can receive the electromagnetic energy from many powering ends at the same time or can provide the electromagnetic energy to many charging ends at the same time, which makes the bidirectional wireless charging device 1 have multiple bidirectional wireless charging functions.
It is worth mentioning that, in the above embodiment, the user needs to manually operate the bidirectional wireless charging device 1 to generate a switch signal and start the charging process. However, in other embodiments, the two bidirectional wireless charging devices 1 and 1 ′ in the bidirectional wireless charging system can automatically start the charging process.
In detail, in other embodiments, the user can set the bidirectional wireless charging devices 1 and 1 ′ to turn on the automatic charging function. When the distance between the bidirectional wireless charging devices 1 and 1 ′ is less than a preset distance, the bidirectional wireless charging devices 1 and 1 ′ would exchange their status messages to inform each other of the current electric quantity. When the current electric quantity of the bidirectional wireless charging device 1 is more than a first threshold value and the current electric quantity of the bidirectional wireless charging device 1 ′ is less than a second threshold value, the bidirectional wireless charging device 1 would start to charge the bidirectional wireless charging device 1 ′.
For example, when the current electric quantity of the bidirectional wireless charging device 1 ′ is less than 20% of the maximum stored power and the current electric quantity of the bidirectional wireless charging device 1 is more than 80% of the maximum stored power, the bidirectional wireless charging device 1 would automatically charge the bidirectional wireless charging device V. In addition, the above embodiment is merely an example for describing the application of the instant disclosure, but it is not limited herein. The skilled in the art can set the predetermined distance, a first threshold value and second threshold value based on the actual operation and needs. Moreover, the user can also choose to turn off the automatic charging function of the bidirectional wireless charging devices 1 and 1 ′, and thus in the instant disclosure the bidirectional wireless charging devices 1 and 1 ′ can optionally turn on their automatic charging function.
On the other hand, in other embodiments, the bidirectional wireless charging system can be set such that the bidirectional wireless charging device 1 periodically sends a switch signal to another bidirectional wireless charging device. When the bidirectional wireless charging device 1 ′ receives the switch signal and the bidirectional wireless charging device 1 ′ has insufficient power, the bidirectional wireless charging device 1 ′ would reply to this switch signal. After receiving the reply of the bidirectional wireless charging device 1 ′, the bidirectional wireless charging device 1 would turn into the power mode and start to charge the bidirectional wireless charging device 1 ′.
In short, the bidirectional wireless charging device provided in the embodiment of the instant disclosure can be used as a powering end or a charging end, so as to increase the convenience of the bidirectional wireless charging system. Moreover, the transceiver chip 10 of the bidirectional wireless charging device provided in the embodiment of the instant disclosure integrates the power mode operation module 103 and the charging mode operation module 104 into a single chip. Thereby, the bidirectional wireless charging device 1 merely needs one control module 101 and one power stage circuit 102 to realize the bidirectional wireless charging function.
Please refer to FIG. 6 , FIG. 6 shows a flow chart of a bidirectional wireless charging device of one embodiment of the instant disclosure in the power mode. The steps of process shown in FIG. 6 are applied to the above bidirectional wireless charging devices 1 and 1 ′. The Step S 601 is starting the powering process. The Step S 602 is making the bidirectional wireless charging device 1 turn into the power mode. The switch signal can be sent from the switch signal generating unit of the bidirectional wireless charging device 1 or from the switch signal generating unit of another bidirectional wireless charging device (such as the bidirectional wireless charging device 1 ′). The Step S 603 is that the bidirectional wireless charging device 1 starts to output the electromagnetic energy to the bidirectional wireless charging device 1 ′.
The Step S 604 is that the bidirectional wireless charging device 1 receives and demodulates a PWM signal PWM′ sent by the bidirectional wireless charging device 1 ′, so as to obtain a status message of the bidirectional wireless charging device 1 ′, which includes an electric quantity in formation of the charging end, an energy adjusting request, an energy maintaining request or a cut-off supply request. The Step S 605 is that the bidirectional wireless charging device 1 determines whether the status message includes a cut-off supply message. If the status message includes a cut-off supply message, it goes to the Step S 606 , and if the status message does not include a cut-off supply message, it goes to the Step S 607 . The Step S 606 is that the bidirectional wireless charging device 1 adjusts the power output by the power stage circuit according to the status message and that it returns to the Step S 603 so as to continue to charge the bidirectional wireless charging device V. The steps for the bidirectional wireless charging device 1 adjusting the power output by the power stage circuit are the same as the above embodiment, and thus the redundant information is not repeated. The Step S 606 is that the bidirectional wireless charging device 1 stops outputting the electromagnetic energy, and the Step S 607 is ending the powering process.
Please refer to FIG. 7 , FIG. 7 shows a flow chart of a bidirectional wireless charging device of one embodiment of the instant disclosure in the charging mode. The steps of the process shown in FIG. 7 are also applied to the above bidirectional wireless charging devices 1 and 1 ′. The Step S 701 is starting the charging process. The Step S 702 is that the bidirectional wireless charging device 1 ′ receives a switch signal and turns into the charging mode. The Step S 703 is that the bidirectional wireless charging device 1 ′ receives a PWM signal PWM from another bidirectional wireless charging device (such as the bidirectional wireless charging device 1 ), so as to charge based on the electromagnetic energy of the PWM signal PWM. The Step S 704 is that the bidirectional wireless charging device 1 ′ converts the electromagnetic energy into a regulated voltage and provides the regulated voltage to the power storage unit 13 ′ for charging.
The Step S 705 is that control unit 1010 ′ of the bidirectional wireless charging device 1 ′ determines whether the power provided from the power storage unit 13 ′ to the bidirectional wireless charging device 1 ′ is within a normal range. As described above, those skilled in the art can set this normal range of power provided by the power storage unit 13 ′ based on need. If the power provided by the power storage unit 13 ′ is within the normal range, it goes to the Step S 706 . If the power provided by the power storage unit 13 ′ is not within the normal range, it goes to the Step S 707 .
The Step S 706 is that the control unit 1010 ′ determines whether the power stored in the power storage unit 13 ′ reaches a predetermined value. If the control unit 1010 ′ determines that the power stored in the power storage unit 13 ′ reaches the predetermined value, it goes to the Step S 708 , otherwise it goes to the Step S 707 . As described above, those skilled in the art can set a predetermined value of power stored in the power storage unit 13 ′ based on need. The Step S 707 is that the control unit 1010 ′ makes the modulation unit 1041 ′ drive the coil 11 ′ to generate a PWM signal PWM′ including an energy adjusting request or an energy maintaining request, so as to inform the bidirectional wireless charging device 1 of its electric quantity information. After the bidirectional wireless charging device 1 receives the PWM signal PWM′, it adjusts the output power according to the status message of the PWM signal PWM′ and continues to provide the electromagnetic energy to the bidirectional wireless charging device 1 ′.
The Step S 708 is that the power stored in the power storage unit 13 ′ reaches the predetermined value, so the control unit 1010 ′ makes the modulation unit 1041 ′ drive the coil 11 ′ to generate a PWM signal PWM′ including a cut-off supply request. After that, the bidirectional wireless charging device 1 ′ outputs the PWM signal PWM′ to the bidirectional wireless charging device 1 , so that that bidirectional wireless charging device 1 stops charging the bidirectional wireless charging device 1 ′. The Step S 709 is ending the charging process.
To sum up, the bidirectional wireless charging device provided by the instant disclosure can be used as a powering end or a charging end to improve the convenience of the bidirectional wireless charging device. Moreover, compared with the traditional bidirectional wireless charging device, the transceiver chip of the bidirectional wireless charging device provided by the instant disclosure integrates the power mode operation module and the charging mode operation module into a single chip. Thereby, merely one control module and one power stage circuit are needed for the instant disclosure to provide the bidirectional wireless charging function, which effectively shrinks the circuit area, decreases the cost and also reduces the system complexity.
In addition, in the transceiver chip provided by the embodiment of the instant disclosure, the power mode operation module and the charging mode operation module are set to use one control module and one power stage circuit together, and the number of pins of the transceiver chip also decreases. In detail, in the power mode, part of the pins of the transceiver chip can be necessarily used for powering. When switching to the charging mode, the above part of the pins would be necessarily used with the change of the transceiver chip's mode. In other words, part of the pins of the transceiver chip is used both in the power mode and the charging mode. Thereby, the number of pins of the transceiver chip can be decreased, which effectively reduces the cost of the transceiver chip.
Moreover, the traditional bidirectional wireless charging device using the electromagnetic induction technology would lose some power after electromagnetic transduction because of the external circuit, which decreases the power obtained by the bidirectional wireless charging device. The bidirectional wireless charging device provided by the embodiment of the instant disclosure integrates the switching circuit, the rectifying circuit and the demodulation circuit into a single transceiver chip, which reduces the power loss and thus increases the efficiency of the bidirectional wireless charging device.
The bidirectional wireless charging device provided by the embodiment of the instant disclosure also provides an automatic charging function. When there is not sufficient power, the bidirectional wireless charging device would automatically search for a nearby bidirectional wireless charging device for charging, so that the user need not manually operate the bidirectional wireless charging device for charging.
The descriptions illustrated supra set forth simply the preferred embodiments of the instant disclosure; however, the characteristics of the instant disclosure are by no means restricted thereto. All changes, alterations, or modifications conveniently considered by those skilled in the art are deemed to be encompassed within the scope of the instant disclosure delineated by the following claims. | The present disclosure illustrates a bidirectional wireless charging device. The bidirectional wireless charging device comprises a transceiver chip which is configured to receive a switch signal. The transceiver chip comprises a power stage circuit and a control module. The power stage circuit is coupled to a coil, and the control module is coupled to the power stage circuit. The power stage circuit is configured to output a voltage to the coil, or to receive an induced voltage from the coil. The control module is configured to control the transceiver chip to enter a power mode or a charging mode based upon the switch signal. When the transceiver chip enters the power mode, the transceiver chip provides the voltage to the coil. When the transceiver chip enters the charging mode, the transceiver chip receives the induced voltage from the coil and charges a power storage unit. | 48,700 |
BACKGROUND OF THE INVENTION
The device of the present invention provides for the permanent recording of the various acts of patient care which are performed. The tape is of such length that a minimum of 30 days permanent recording is provided. The area in which the entry is made is covered by a slide unit which is movable between a position in which an entry can be made and a closed position in which, after an entry has been made, the entry is hidden from view. When the slide is then moved forwardly to permit an additional entry on the tape, the tape is advanced and the previous entry is moved forward out of sight. Therefore, at no time after an entry is completed can it be seen to identify the time or the type of entry previously made except by an authorized person. Thus, it is impossible for an unauthorized person to identify when the patient was last cared for. Further, no hospital employee can be aware of another staff member's entry. This prevents multiple entries to cover up any lack of regular patient inspection. Personnel will thus be protected if a patient is inspected as required by law on a regular basis by an assigned aide or nurse. Thus, the hospital and personnel will have a permanent record to present at any legal hearing should one occur.
In addition, the time of wet-bed change is immediately recorded as are patient meals. If a patient does not partake of the food served, this fact can also be noted and the time recorded. Patient body position changes will be noted as to time, thus minimizing decubitus disputes. This is of extreme importance because a position change is required every 2 hours for a patient confined to a bed. The Director of Nurses can note the time she checked on the patient so that patient accident and incidents are lessened, preventing increased insurance rates.
The device makes it impossible to leave space available for nurse's notes for a later nurse's protection. The charts would not coincide. State personnel and Director of Nurses, only, will have a key to the patient care recording unit for instant removal to verify verbal nursing comments. Nursing personnel cannot dispute poor patient care should a dispute arise as to their personnel records. In many states, citations are issued and fines levied. Also many citations must be posted on the wall of the hospital. By eliminating citations and any fines imposed prevents embarrassment to the hospital relative to patient care.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view showing the device in position on the foot board of a bed.
FIG. 2 is a partial perspective view showing the tape in position for recordation of a nurse's entry.
FIG. 3 is a perspective view illustrating the construction of the device and the manner of providing the tape.
FIG. 4 is a plan view of the device.
FIG. 5 is a section taken along the line 5--5 in FIG. 4.
FIG. 6 is a view taken along the line 6--6 in FIG. 5.
FIG. 7 is a view taken along the line 7--7 in FIG. 5.
FIG. 8 is a perspective view of a modified form of the device.
FIG. 9 is a plan view of the device shown in perspective in FIG. 8.
FIG. 10 is a section taken along line 10--10 in FIG. 9.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, the recording device of this invention, generally indicated at 11, is mounted on a foot board 12 of a patient's bed by flanges 13 which depend from the device and fit over the foot board. The device is retained in place by screws 14 which force plate 15 into tight engagement with the foot board 12 (see FIG. 7). The device includes a receptable 16 closed by a removable door 17, the latter being adapted to be locked in a closed position by lock 18.
Mounted upon side wall 19 of the device is a fixed shaft 21 and a movable shaft 22. Shaft 21 provides a support for a roll of tape 23, the tape being fed from that roll over a support 24 and thence about a second roll 26 on shaft 22. Roll 26 has a keyway 27 thereon fitting a key 28 on roll 22.
To advance the tape from roll 23 to roll 26, I provide a ratchet wheel 31 on shaft 22, the latter having a plurality of ratchet teeth 32, the teeth being successfully engaged by a pawl 33 held against the ratchet wheel 31 by spring 36. Pawl 33 is mounted on a bracket 37 secured on the underside of the slidable top 38. Slidable top 38 is supported on the top of the device in channel 39. When the movable top 38 is pushed in the direction of the arrow in FIG. 2 by engagement with its handle 41, the tape is advanced one step to provide a fresh writing surface upon which an entry can be made by a nurse or other authorized personnel. It is impossible to back up the tape because of the engagement of the ratchet wheel 31 with a dog 43 hinged as at 44 on the side wall 19 under the pressure of a spring 46.
When the movable top 38 is returned to a position in which the entry on the tape is concealed, the tape remains in this position until the movable top 38 is again advanced to open position to expose a length of tape so that a fresh entry can be made. Previous entries are wound up upon the roll 26 and thus cannot be viewed by one not having means to operate the lock 18.
In that form of the device shown in FIGS. 8, 9 and 10, the recording device is generally indicated at 51. This includes a door 52 hinged as at 53 along the bottom edge of the device. Shafts 54 and 55 are mounted in spaced relation upon vertical side wall 56. A roll of tape 57 is mounted upon shaft 54 and tape from this roll passes upwardly over a writing shelf 58 mounted beneath an opening 59 in the top 61 of the device. The tape extends to a spool 62 mounted upon shaft 55 which spool is in driving engagement with the shaft 55. Mounted upon shaft 55 is a ratchet wheel 63 which is effective to rotate shaft 55. Rotation of the shaft 55 is effected by means of a pawl 64 which is selectively engaged with ratchet wheel 63 under the tension applied by spring 65. The pawl is made in the form of a bell crank, one end of which is hinged as at 66 on a lever 67 which is fixed on the underside of slidable top 68. The slidable top has handle 69 and is movable therewith between a closed position, as appears in FIGS. 8, 9 and 10, and the forward position in which slidable top is advanced to expose that portion of the tape supported on the shelf 58 immediately below opening 59 in top 61.
When it is desired to make an entry on the tape, the lever 67 is advanced from the full line position in which it appears in FIGS. 8, 9 and 10 to the dotted line position shown in FIG. 10. Movement of the top by the lever 67 is effective to rotate the ratchet and so advance the tape, thus withdrawing the previous entry from view and winding the tape up on spool 62. When the entry has been completed, the arm 67 is moved to the right in FIG. 10 which serves to retract the pawl to its starting position in which it can again advance the ratchet wheel.
If it is desired to remove the tape from the device for examination, this can be achieved quite readily by opening the lock 18 and lowering the door 52. Shaft 54 is formed with a square recess 71 in which one can insert the end of key 72 to permit rotation of shaft 54 and return of the tape from spool 62 during the rotation of shaft 54. It is, of course, necessary for one to move the pawl 64 from engagement with the ratchet wheel 63 so that the latter may be rotated in a clockwise direction.
The unit is not necessarily limited to bed attachment but may also be used in any area associated with a patient's care and requiring verification of either time or events pertinent for future reference. | A device is provided for recording written information dealing with the care of a patient. Each additional entry advances the previous entry and records it as a permanent record on the same tape roll. Each earlier entry is thereby hidden from view, thus preventing the alteration of records. | 7,791 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a device for exchanging objects, in particular writing instruments, between two holders embodied substantially alike and open at one side. To effect the transfer of an object by means of the approach of their open sides oriented toward one another, these holders are movable relative to one another in a plane which extends substantially at right angles to their longitudinal axes.
2. Brief Description of the Prior Art
In a known device of this kind (described in German published application, DE-OS No. 29 13 690), a change of writing instruments is to be accomplished in a computer-controlled drawing system. A writing instrument is held in the holder of the drawing head by two leaf springs, disposed opposite one another, with ends lightly gripping the writing instrument and pressing it against a stationary inner face, located opposite the opening in the holder, of the receiving area. The free ends of the leaf springs protrude somewhat in the direction of the transfer of the writing instrument to the holder of the instrument magazine, and the holder in the instrument magazine has two correspondingly embodied springs.
If the writing instrument is held in the holder of that drawing head and the drawing head approaches the instrument magazine, then in this state the free ends of the springs of the holder provided in the instrument magazine are located closer together, because of the absence of one writing instrument, than the free ends of the springs of the holder in the drawing head, which are spread apart by the writing instrument inserted between them. As a result, the free ends of the springs of the instrument magazine come into contact with the outer circumference of the writing instrument, and upon the further approach of the drawing head toward the instrument magazine these free ends are spread apart. As a consequence, they touch the protruding free ends of the springs of the holder in the drawing head and push their way in between these springs and the writing instrument, until they come to engage the writing instrument and thereby withdraw it from the holder of the drawing head upon the reversal of the movement of the drawing head.
When a writing instrument is inserted from the instrument magazine into the drawing head, the springs of the holders function in the same manner as described above, but in this case the springs of the holder of the drawing head push their way in between the springs of the holder of the instrument magazine and the writing instrument.
Although this known device for exchanging writing instruments functions relatively simply and reliably, it has the disadvantage that the position of the writing instrument in the holder of the drawing head is not defined precisely, because it is substantially determined by the characteristics of the two springs, which can vary with use. As a result, it may happen that when exchanging one writing instrument producing a particular line width for another which produces a line of different width, for instance, and attempting with the new instrument to continue a line drawn by the old instrument, the new line having the different width will not be centered precisely with respect to the line segment drawn previously.
SUMMARY OF THE INVENTION
It is the object of the invention to create a device of simple structure for exchanging objects, in particular writing instruments, in which the position of the object in a holder is precisely defined and does not undergo any variation, even with long use.
In order to attain this object, a device of the general type discussed above is embodied in such a manner that the object is held in a receptacle having an uneven number of sides, and in cross section substantially having the shape of a regular, convex n-gon. At each corner, the receptacle has an element of ferromagnetic material or a permanent magnet, all these elements being disposed at the same level. In the receiving area, each holder has on the inner face located opposite its open side either a permanent magnet or an element of ferromagnetic material, disposed on the same level as the elements of ferromagnetic material or permanent magnets on the receptacle. Finally, the receptacle, which is held in a holder by means of the aligned position of an element of ferromagnetic material and a permanent magnet, can be rotated by an integral multiple of half the inside angle of the n-gon upon approaching the other holder as a result of the engagement therewith, and it can be transferred into the other holder by means of the aligned position of an element of ferromagnetic material and a permanent magnet.
In the device according to the invention, the fixation of the object, or of the receptacle containing the object, in a holder is thus effected by means of magnetic force--that is, in a non-wearing manner--so that even after long use the position in which the object is held inside the holder always remains the same. For transfer to the other holder, because of the approach of the two holders toward one another, the receptacle containing the object is rotated about its longitudinal axis in such a manner that the areas which attract one another because of magnetic force are displaced relative to one another, and corresponding areas in the other holder which also attract one another magnetically are brought into an aligned position. That is to say, the receptacle of the other holder is attracted magnetically and is fixed in this holder in a position which is replicable even after a long period of use. As a result of the rotation of the receptacle, the holder originally containing this receptacle no longer holds it by magnetic force, because the rotation has instead effected a magnetic fixation of the receptacle in the other holder. Hence, it is now possible to remove the other holder together with the receptacle from the holder which had originally fixed this receptacle.
In order to keep the receptacle in the holder in a position which is precisely aligned in the axial direction, each holder and the receptacle can have two groups of permanent magnets and of elements of ferromagnetic material disposed spaced apart axially from one another, at uniform distances from one another. As a result, the receptacle in the holder is thus held at two areas located at an axial distance from one another by magnetic force, and the axial alignment of the receptacle is thus assured.
In the receiving area of each holder, at least one guide face for the receptacle may be provided between the groups, so that during the transfer operation this receptacle is put into the desired position in the holder by the guide face.
In addition, the receptacle can be brought into an engagement with the associated holder such that it cannot be shifted in the axial direction. For instance, by an engagement between the guide face and a recess provided on the receptacle. By this means, it is also possible to fix the height of the receptacle relative to the holder in a replicable manner.
In the simplest design of the receptacle, it may in cross section have substantially the shape of a triangle.
In order to attain the rotation of the receptacle in one holder upon approaching the other holder or being approached thereby, at least one portion of the opposing free edge areas of the open sides of the holders may protrude to different extents, beyond the inner face of the receiving area which carries the permanent magnet or the element of ferromagnetic material. As a result, the edge area of the holder not containing the receptacle (which protrudes farther out) comes into contact with the receptacle sooner than the other free edge area (which does not protrude as far) so that a rotation of the receptacle is thereby effected.
With the free edge areas of the open sides of the holders embodied in such a manner, the longitudinal axes of the holders may be located, in the transfer position: on a first straight line extending through the centers of the permanent magnets or elements of ferromagnetic material, provided therein. In order to be moved away from one another, the holders can be movable relative to one another along this line. Upon approaching one another, the holders can be movable relative to one another along a second straight line which extends at an acute angle from the first line, for instance at an angle of 35° to 50° (and preferably from 40° to 45°), and passes through the longitudinal axes of the holders. When the device is embodied in such a manner, the approach of the holders to one another is thus effected along a straight line which is different from the straight line along which the holders are moved apart from one another.
The invention will now be described in detail, referring to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1, in a simplified perspective view, shows a plotter in which a holder of a device for exchanging writing instruments may be seen;
FIG. 2, in perspective views, shows two holders, one of which holds the writing instrument receptacle;
FIG. 3 is a different view of one of the holders of FIG. 2;
FIG. 4 is a section taken along the line IV--IV of FIG. 3;
FIG. 5 is a section taken along the line V--V of FIG. 3;
FIG. 6 is a vertical section taken through the writing instrument receptacle of FIG. 2;
FIG. 7 is a section taken along the line VII--VII of FIG. 6;
FIGS. 8-12 shows the positions of a holder in sequence in the course of the removal of the receptacle from a stationary holder; and
FIGS. 13-17 show the positions of a holder in sequence in the course of the transfer of the receptacle from this holder to the stationary holder.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The invention will be described herein in terms of a device for exchanging writing instruments, such as may be used in the conventional flat bed plotter 1 shown in FIG. 1, which has a bar 2 that can be moved back and forth in one direction over the drawing surface 3, and a holder 5 secured to bar 2 by means of a drawing head, not shown. The drawing head is movable back and forth on the bar 2 in the longitudinal direction thereof in the conventional manner. Magazines 4 for writing instruments are also present on the stationary frame of the plotter 1, and are shown in a highly simplified and schematic manner. Holders not shown, but corresponding to the holder 5, are secured in these instrument magazines 4.
Two holders 5, 5' of identical design are shown in FIG. 2, each in the approximate shape of half a cylindrical shell, the holders facing one another with their open sides. The various parts of the two holders are identified with the same reference numerals, but those of one holder, which will later be assumed to be the stationary holder, are marked with a prime ('). Because the design of the two holders is the same, it will be sufficient to describe only one holder in detail.
The holder 5, which by way of example is of plastic or non-ferromagnetic metal, has two permanent magnets 6, 7 on its inner face located opposite the open side. The permanent magnets 6, 7 are located on a straight line, extending parallel to the longitudinal axis and are spaced apart axially from one another. Between these permanent magnets, upon the inner face is a protruding guide face 9, and an oblong slot 8 which is provided on a connecting line drawn between the permanent magnets 6 and 7, in the vicinity of the guide face. The holder can be secured on some component of the exchanging device, for instance on the bar 2 or on an instrument magazine 4 of the plotter (FIG. 1), by means of this oblong slot 8. As is shown more particularly in FIG. 2 and 5, one lateral limiting wall of the receiving area of the holder 5 is longer than the other lateral limiting wall, so that free edge area 11 is more remote from the permanent magnets 6, 7 than is free edge area 10. In the assembled state, the longer lateral wall area of one holder (for instance holder 5), is located with its free edge area 11 opposite the shorter wall area of the other holder (for instance holder 5')--that is, opposite the free edge area 10' (FIG. 2)--so that when the holders 5, 5' have made their full approach toward one another and are fully in alignment, they approximately form a ring.
In FIG. 2, a receptacle 20 is held in the holder 5' and has a substantially triangular cross section with rounded corners (FIG. 7). A central bore 21 extends through this receptacle 20 along its longitudinal axis. When the receptacle 20 is positioned in one of the holders, its longitudinal axis coincides with that of the holder, for instance the longitudinal axis 12' of the holder 5' in FIG. 2. The central bore 21 serves to receive the objects which are to be exchanged for one another and is therefore adapted in its shape and size to the shape and size of the objects. Elements 22, 23, 24 of ferromagnetic material are provided on each corner of the receptacle 20 in a common radial plane, and elements of ferromagnetic material having the same shape as the elements 22, 23, 24 are disposed, at a distance from the latter which is equal to the distance between the permanent magnets 6, 7 in the holder 5, on each corner of the receptacle in a second radial plane; of these, only the element 25 is shown in FIG. 6.
In the vicinity of each corner, a groove extending in the circumferential direction is embodied between the elements of ferromagnetic material spaced apart axially from one another. In FIG. 6 only the groove 26 is shown, located between the elements 22 and 25. The size of these grooves in the direction of the longitudinal axis of the receptacle 20 corresponds to the length of the guide face 9 of the holder 5 in the direction of the longitudinal axis 12. Hence, when the receptacle 20 is inserted in the holder 5, the guide face 9 engages this groove and reliably prevents a shift in position of the receptacle inside the holder in the direction of the longitudinal axis 12.
The receptacle 20, like the holder 5, may be fabricated of plastic or of non-ferromagnetic metal.
If the position of the holders 5, 5' and of the receptacle 20 as shown in FIG. 2 is taken as the point of departure, then the resultant sectional illustration (extending in the same plane as section V--V of FIG. 3 taken through the holder 5 and section VII--VII of FIG. 6 taken through the receptacle) is shown in FIG. 8. In FIG. 8 the receptacle 20 is seated within the holder 5', and the guide face 9' extends within the corresponding groove of receptacle 20, which is provided in the corner area between the ferromagnetic material element 23 and the ferromagnetic material element provided some distance beneath it. In this position, the central axis of the permanent magnet 6' is located on the central axis of the element of ferromagnetic material 23, so that these two elements attract one another by magnetic force. A permanent magnet 7' (not shown in FIG. 8), attracts an adjacent element of ferromagnetic material of the receptacle 20 in the same manner. The central axis of the receptacle 20 is located in the central axis 12' of the holder 5'. The holder 5 is located at a distance from the holder 5' and offset laterally somewhat therefrom. Its central axis 12 is located on a straight line 14, which extends through the central axis 12' of the holder 5'. Straight line 14 is shown intersecting the straight line 13, which passes through the centers of the permanent magnet 6' and of the element 23 of ferromagnetic material as well as through the central axis 12', at an acute angle of approximately 41.
In order to effect transfer of the receptacle 20 from the holder 5' to the holder 5, the holder 5 is moved out of the position shown in FIG. 8, in which the open sides of the holders 5, 5' are oriented toward one another, toward the holder 5' in the plane of the drawing without tilting or twisting in such a manner that the central axis 12 of the holder moves along the line 14. As a result of this approach, the free edge area 11 of the holder 5 comes into contact with the corner of the receptacle 20 in which the element 22 of ferromagnetic material is located (FIG. 9). Further, upon approaching still closer, the free edge area 11 rotates the receptacle 20 counterclockwise in the holder 5 (FIG. 10). During this rotation, the guide face 9' remains in engagement with the groove between the element 23 and the element of ferromagnetic material located below it. Hence, an axial shifting of the receptacle is not possible, although the element 23 of ferromagnetic material is moved out of the vicinity of the permanent magnet 6' and the element of ferromagnetic material located below this element 23 is correspondingly moved out of the vicinity of the permanent magnet 7' and the holder is thereby raised as a result of magnetic force. Once the holder 5 has approached the holder 5' to its closest extent, and the axis 12 of the holder 5 and the axis 12' of the holder 5' to its closest extent, and the axis 12 of the holder 5 and the axis 12' of the holder 5' coincide (FIG. 11), then the receptacle 20 has been rotated to such an extent that the ferromagnetic elements 22 and 23 of the receptacle 20 are at a great distance from the permanent magnet 6', while the element 24 of ferromagnetic material is in alignment with the permanent magnet 6 of the holder 5. Thus, the element of ferromagnetic material located below the element 24 is also in alignment with the permanent magnet 7, and the receptacle 20 is thus attracted by the permanent magnets 6 and 7. The axial positioning of the receptacle 20 is thereby effected, in the same manner as with the movement and the restraint of the receptacle 20 in the holder 5', by means of the engagement of the guide face 9 with the groove provided between the element 24 and the element of ferromagnetic material located below it.
Since in the position shown in FIG. 11 the receptacle 20 is thus held by the holder 5 by magnetic force, yet there is no longer any magnetic force existing between the receptacle 20 and the holder 5', it is possible to remove the receptacle 20 from the holder 5' by moving the holder 5 with its longitudinal axis 12 along the straight line 13, and the receptacle 20 can then be moved away together with the holder 5 (FIG. 12).
Should it be desired to transfer the receptacle 20 from the movable holder 5 to the stationary holder 5', the holder 5 is shifted parallel to the straight line 13. Thereby, central axis 12 of movable holders is located on a straight line 15 extending parallel to the straight line 13 (FIG. 13). Subsequently, an approaching movement of the holder 5 toward the holder 5' takes place, in which the central axis 12 of the holder 5 is moved along the straight line 14 (FIG. 14), as in the case of the approach movement described earlier. The result is that the free edge area 11' of the holder 5' comes into contact with the receptacle 20 having the element 23 of ferromagnetic material. If this approach movement is continued, and as a result of this engagement, a counterclockwise rotation of the receptacle 20 inside the holder 5 occurs. Consequently, the element 24 of ferromagnetic material moves clear of the permanent magnet 6 and the element of ferromagnetic material located below the element 24 moves clear of the permanent magnet 7 (FIG. 15). This approaching movement ends when the longitudinal axis 12 of the holder 5 coincides with the longitudinal axis 12' of the holder 5' (FIG. 16). In this position, the element 22 of ferromagnetic material and the permanent magnet 6' (like the element 25 of ferromagnetic material 25 and the permanent magnet 7'), are located opposite one another, while no restraining magnetic force remains between the receptacle 20 and the holder 5. In this position for receptacle 20, the holder 5 can thus be removed from the holder 5' by moving it with its longitudinal axis 12 along the line 13, and the receptacle 20 will be held in the holder 5' by magnetic force (FIG. 17).
In the above description, it has been assumed that permanent magnets are provided in the holders, while elements of ferromagnetic material are provided in the receptacles. Naturally it is also possible to replace the permanent magnets in the holders with elements of ferromagnetic material instead and then to replace the elements of ferromagnetic material in the receptacle with permanent magnets. The only criterion is that with a corresponding, aligned positions of the permanent magnet and the element of ferromagnetic material, a magnetic force should be exerted between the holder and the receptacle which keeps these parts together.
While a preferred embodiment of the invention has been shown and described, the invention is to be limited solely by the scope of the appended claims. | In a device for exchanging objects, in particular writing instruments, two substantially identically embodied holders (5, 5') which are open at one side are provided. These holders are movable relative to one another in a plane extending substantially at right angles to there longitudinal axes (12, 12'). The object to be exchanged is held in a receptacle (20), which in cross section has substantially the shape of a regular, convex n-gon having an uneven number of sides. At each corner of the receptacle (20), there is an element of ferromagnetic material (22, 23, 24), and there is a permanent magnet (6, 6') on the inner face, located opposite the open side, of the receiving area of each holder (5, 5'). The receptacle (20) is positionally fixed in a holder (for instance, 5') by means of the aligned position of an element (23) of ferromagnetic material and of a permanent magnet (6', for example). By means of an approach toward the other holder (5'), the receptacle (20) is rotated, so that the permanent magnet (6) of the other holder (5) enters into an aligned position with one element (24) of ferromagnetic material of the receptacle (20), while the magnetic effect between the receptacle (20) and the one holder (5') is broken (FIG. 8). | 21,307 |
This application is a continuation-in-part of U.S. application Ser. No. 10/143,380, filed May 10, 2002 now abandoned (which is incorporated in its entirety as a part hereof), which claimed the benefit of U.S. Provisional Application No. 60/290,297, filed May 11, 2001.
FIELD OF THE INVENTION
This invention relates to antimicrobial polyester-containing articles and methodology for the preparation of antimicrobial polyester-containing articles utilizing chitosan and chitosan-metal complexes as the antimicrobial agent.
TECHNICAL BACKGROUND OF THE INVENTION
This invention relates to the use of chitosan and chitosan-metal complexes to generate polyester-containing articles having antimicrobial properties.
PCT application WO 00/49219 discloses the preparation of substrates with biocidal properties. The deposition of solubilized chitosan on polyester, among other materials, followed by treatment with silver salts, reduction of the silver salt and crosslinking the chitosan is disclosed to yield a durable biocidal article. The application also discloses the crosslinking of the chitosan after it is applied, either before or after the silver salt treatment.
JP Kokai H9-291478 discloses a process for the application of a chitosan derivative to polyester fabric comprising UV treatment of the polyester fabric followed by application of a chitosan-derived quaternary ammonium base. The UV irradiation serves to generate free radicals on the surface of the polyester fabric to which the chitosan is subsequently attached. H. Shin et al, Sen - I Gakkaishi, 54(8), 400–406 (1998) discloses similar UV fabric treatment and also a low temperature air plasma treatment prior to chitosan treatment.
JP Kokai H8-22772 discloses a process for the manufacture of an antibacterial acrylic yarn which comprises dipping, in an aqueous acidic chitosan solution, a wet spun yarn from an acrylonitrile-based polymer solution, neutralizing with an aqueous alkali solution, drying and densifying. The process may be carried out batch-wise or continuously. The chitosan is absorbed on the surface of the yarn and deposited in micro-voids within the yarn before drying.
S. Matsukawa et al., Sen - I Gakkaishi, 51(1), 51–56 (1995) disclose the modification of polyester fabrics using chitosan. The polyester was hydrolyzed with caustic soda, neutralized with 1% acetic acid solution, then treated with a chitosan solution and, optionally, with a crosslinking agent.
SUMMARY OF THE INVENTION
This invention provides an antimicrobial polyester-containing article having chitosan grafted onto the article and optionally, containing one or more metal salts, one or more carboxyl-containing polymers or combination thereof.
Further disclosed is a process for preparing antimicrobial polyester-containing articles comprising the sequential steps of:
(a) providing a polyester-containing article; (b) contacting the polyester-containing article with a basic solution; (c) optionally, washing the article produced in step (b); (d) contacting the article produced in step (b) or step (c) with a strong mineral acid solution; (e) optionally, washing the article produced in step (d); (f) contacting the article produced in step (d) or step (e) with a solution comprising a chitosan agent selected from the group consisting of chitosan, chitosan salts and chistosan derivatives; (g) optionally, heating the article produced in step (f); (h) isolating the article produced in step (f) or step (g); and (i) optionally, heating the article isolated in step (h) at a temperature higher than the temperature of step (g).
Further disclosed is a continuous process for producing an antimicrobial polyester-containing article comprising the sequential steps of:
(a) providing a feed station on which is disposed a polyester-containing article and a take-up station capable of receiving the polyester-containing article; (b) drawing the article from the feed station through a first treatment station wherein said article is exposed to a basic solution; (c) optionally drawing the step (b)-treated article through a second treatment station wherein the article is exposed to water; (d) drawing the step (b)- or step (c)-treated article through a third treatment station wherein the article is exposed to a strong mineral acid solution; (e) optionally, drawing the step (d)-treated article through a fourth treatment station wherein the article is exposed to deionized water; (f) drawing the step (d)- or step (e)-treated article through a fifth treatment station wherein the article is exposed to a solution comprising a chitosan agent; (g) optionally, heating the step (f)-treated article after it exits the chitosan treatment station; and (h) causing the step (f)- or step (g)-treated article to be received on and accumulate on the take-up station.
BRIEF DESCRIPTION OF THE DRAWINGS
The drawings consist of 20 figures as follows:
FIG. 1 is a diagram showing the antimicrobial effect of chitosan grafted on 3GT knit fabric vs. Listeria monocytogenes ATCC 15313.
FIG. 2 is a diagram showing the antimicrobial effect of chitosan grafted on 2GT knit fabric vs. Klebsiella pneumoniae ATCC 4352.
FIG. 3 is a diagram showing the antimicrobial effect of chitosan grafted on 2GT knit fabric vs. Candida albicans ATCC 10231.
FIG. 4 is a diagram showing the antimicrobial effect of chitosan grafted on 3GT woven fabric vs. Staphylococcus aureus ATCC 6538.
FIG. 5 is a diagram showing the antimicrobial effect of chitosans of various molecular weights grafted onto 2GT woven microfiber fabric vs. E. coli ATCC 25922.
FIG. 6 is a diagram showing the antimicrobial effect of chitosans of various molecular weights grafted onto 2GT woven microfiber fabric vs. Staphylococcus aureus ATCC 29213.
FIG. 7 is a diagram showing the antimicrobial effect of chitosan grafted onto 3GT fabrics with and without silver nitrate treatment vs. Salmonella cholerasuis ATCC 9239.
FIG. 8 is a diagram showing the antimicrobial effect of chitosan grafted on 3GT fabrics with and without copper sulfate treatment vs. E. coli O157:H7.
FIG. 9 is a diagram showing the antimicrobial effect of chitosan grafted on 2GT fabrics with various concentration silver nitrate solution post treatment vs. Staphylococcus aureus ATCC 6538.
FIG. 10 is a diagram showing the antimicrobial effect of chitosan grafted on 2GT fabrics after various hydrolysis times with and without a 0.1% silver nitrate post treatment vs. E. coli O157:H7.
FIG. 11 is a diagram showing the antimicrobial activity of free chitosan vs. grafted chitosan on 2GT fabric vs. Staphylococcus aureus ATCC 6538.
FIG. 12 is a diagram showing the antimicrobial activity of grafted chitosan on 2GT knit fabrics with various after-treatments of polyacrylic acid, additional chitosan and/or silver nitrate treatment vs. E. coli 25922.
FIG. 13 is a diagram showing the antimicrobial effect of chitosan grafted on 2GT fiber by processing in a package dyer vs. E. coli ATCC 25922.
FIG. 14 is a diagram showing the antimicrobial effect of chitosan grafted on 2GT fiber by processing in a package dyer and single-end sizer vs. E. coli ATCC 25922.
FIG. 15 is a diagram showing the antimicrobial effect of a chitosan-treated polyester and Lycra® blend fiber vs. E. coli ATCC 25922.
FIG. 16 is a diagram showing the antimicrobial effect vs. E. coli ATCC 25922 of chitosan treatment of yarns commonly occurring in polyester blends.
FIG. 17 is a diagram showing the antimicrobial effect of a chitosan-treated polyester/rayon nonwoven fabric vs. E. coli ATCC 25922.
FIG. 18 is a diagram showing the antimicrobial effect of a chitosan-treated polyester/wood pulp nonwoven fabric vs. E. coli ATCC 25922.
FIG. 19 is a diagram showing the antimicrobial effect of a chitosan-treated bicomponent (2GT/3GT) polyester fiber vs. E. coli ATCC 25922.
FIG. 20 is a schematic diagram of the continuous process of the invention for making antimicrobial polyester-containing articles.
DETAILED DESCRIPTION OF THE INVENTION
The present invention involves the preparation of antimicrobial polyester-containing articles that have chitosan grafted thereon. Chitosan is the commonly used name for poly-[1-4]-β-D-glucosamine. Chitosan is chemically derived from chitin, which is a poly-[1-4]-β-N-acetyl-D-glucosamine which, in turn, is derived from the cell walls of fungi, the shells of insects and, especially, crustaceans. As used herein, the term “grafted” means that the chitosan is bound to the polyester substrate by either ionic (electrostatic) or covalent bonding. Grafting of the chitosan to the polyester article may be confirmed by Electron Spectroscopy for Chemical Analysis (ESCA) [see, for example, Xin Qu, Anders Wirsen, Bjorn Orlander, Anne-Christine Albertsson, Polymer Bulletin, (2001), vol. 46., pp. 223–229 and Huh, M. W., Kang, I., Lee, D. H., Kim, W. S., Lee, D. H., Park, L. S., Mln, K. E., and Seo, K. H., J. Appl. Polym. Sci. (2001), vol. 81, p. 2769]. Grafting is also established by the literature report of Ga-er Yu, Frederick G. Morin, Geffory A. R. Nobes, and Robert H. Marchessault, in Macromolecules, (1999), vol. 32, pp. 518–520). ESCA data demonstrate that the chitosan-modified surfaces of the polyester-containing articles of the present invention are similar in composition to those of the chitosan starting materials. The ESCA data also show that these surfaces have a significant level of nitrogen that is incorporated in a salt form, which provides evidence that the chitosan in physically linked to the surface through ionic interactions.
Polyesters comprise those polymers prepared from diols and dicarboxylic acids. Dicarboxylic acids useable in the preparation of polyesters include, but are not limited to, unsubstituted and substituted aromatic, aliphatic, unsaturated, and alicyclic dicarboxylic acids and the lower alkyl esters of dicarboxylic acids having from 2 carbons to 36 carbons. Specific examples of the desirable dicarboxylic acid component include terephthalic acid, dimethyl terephthalate, isophthalic acid, dimethyl isophthalate, 2,6-napthalene dicarboxylic acid, dimethyl-2,6-naphthalate, 2,7-naphthalenedicarboxylic acid, dimethyl-2,7-naphthalate, 3,4′-diphenyl ether dicarboxylic acid, dimethyl-3,4′diphenyl ether dicarboxylate, 4,4′-diphenyl ether dicarboxylic acid, dimethyl-4,4′-diphenyl ether dicarboxylate, 3,4′-diphenyl sulfide dicarboxylic acid, dimethyl-3,4′-diphenyl sulfide dicarboxylate, 4,4′-diphenyl sulfide dicarboxylic acid, dimethyl-4,4′-diphenyl sulfide dicarboxylate, 3,4′-diphenyl sulfone dicarboxylic acid, dimethyl-3,4′-diphenyl sulfone dicarboxylate, 4,4′-diphenyl sulfone dicarboxylic acid, dimethyl-4,4′-diphenyl sulfone dicarboxylate, 3,4′-benzophenonedicarboxylic acid, dimethyl-3,4′-benzophenonedicarboxylate, 4,4′-benzophenonedicarboxylic acid, dimethyl-4,4′-benzophenonedicarboxylate, 1,4-naphthalene dicarboxylic acid, dimethyl-1,4-naphthalate, 4,4′-methylene bis(benzoic acid), dimethyl-4,4′-methylenebis(benzoate), oxalic acid, dimethyl oxalate, malonic acid, dimethyl malonate, succinic acid, dimethyl succinate, methylsuccinic acid, glutaric acid, dimethyl glutarate, 2-methylglutaric acid, 3-methylglutaric acid, adipic acid, dimethyl adipate, 3-methyladipic acid, 2,2,5,5-tetramethylhexanedioic acid, pimelic acid, suberic acid, azelaic acid, dimethyl azelate, sebacic acid, 1,1 1-undecanedicarboxylic acid, 1,10-decanedicarboxylic acid, undecanedioic acid, 1,12-dodecanedicarboxylic acid, hexadecanedioic acid, docosanedioic acid, tetracosanedioic acid, dimer acid, 1,4-cyclohexanedicarboxylic acid, dimethyl-1,4-cyclohexanedicarboxylate, 1,3-cyclohexanedicarboxylic acid, dimethyl-1,3-cyclohexanedicarboxylate, 1,1-cyclohexanediacetic acid, metal salts of 5-sulfo-dimethylisophalate, fumaric acid, maleic anhydride, maleic acid, hexahydrophthalic acid, phthalic acid and the like and mixtures derived therefrom.
Diols useful in the preparation of polyesters include, but are not limited to, unsubstituted, substituted, straight chain, branched, cyclic aliphatic, aliphatic-aromatic or aromatic diols having from 2 carbon atoms to 36 carbon atoms. Specific examples of the desirable diol component include ethylene glycol, 1,3-propanediol, 1,2-propanediol, 1,2-, 1,3- and 1,4-butanediol, 1,5-pentane diol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, dimer diol, isosorbide, 4,8-bis (hydroxymethyl)-tricyclo [5.2.1.0/2.6]decane, 1,2-, 1,3- and 1,4-cyclohexanedimethanol, and the longer chain diols and polyols made by the reaction product of diols or polyols with alkylene oxides including di(ethylene glycol), tri(ethylene glycol), poly(ethylene ether) glycols, poly(butylene ether) glycols and the like and mixtures derived therefrom.
The preferred polyesters useful herein are poly(ethylene terephthalate) (“2GT”), poly(trimethylene terephthalate) (“3GT”), and blends and copolymers thereof.
The term “polyester-containing article” as used herein means an article that has a surface composition of at least 10% polyester by area.
In apparel applications, garments comprising polyester often include other components, such as acrylic, wool, silk, cotton, linen, flax, hemp, rayon, cellulose, wood pulp, cellulose acetate or triacetate, nylon 6 or nylon 66, poly(m-phenylene isophthalamide) (‘PMIA,’ available from E. I. du Pont de Nemours and Company, Wilmington, Del., U.S.A. under the trademark Nomex®), poly(p-phenylene terephthalamide) (‘PPTA,’ available from E. I. du Pont de Nemours and Company under the trademark Kevlar®), polyolefins such as polypropylene and polyethylene, fiberglass, Lycra® spandex (available from E. I. du Pont de Nemours and Company), and elastomers. Polyesters other than poly(ethylene terephthalate) may also be present, for example, a copolymer with a low melt temperature that is used as a binder fiber in fiberfill.
Combination of the fibers listed above can be used in the present invention for added benefits. Such fiber combinations can be prepared by any means known to those skilled in the art. “Bicomponent” filaments in which two polymers are arranged side-by-side or in a sheath-core arrangement can be formed during the spinning process. 2GT/3GT bicomponent fibers such as are disclosed in U.S. Pat. No. 3,671,379, herein incorporated by reference, are one example useful in the present invention.
Another means of preparing fiber combinations is by intimate blending of staple fibers; i.e., as the staple yarn is spun, the different fibers can be combined in either a carding or drawing process. Fiber combinations can also be prepared by knitting or weaving yarns, staple, or filament of different composition into the same fabric. In the case of Lycra® spandex (E. I. de Nemours and Company, Wilmington, Del.), the spandex is added in staple yarn at either the spinning step or during fabric production, such as plating in knitting.
As a first step of the process of the present invention, polyester-containing articles are pretreated. This pretreatment involves hydrolyzing the surface of said polyester-containing article to prepare it for subsequent attachment of chitosan groups. The pretreatment is achieved by the hydrolytic rupture of some of the ester bonds in the polyester-containing articles to generate carboxylate groups.
The hydrolysis treatment involves exposure of the polyester-containing article to an aqueous solution of a base. All soluble Group I, II, and III hydroxides, ammonium hydroxide, and alkyl-substituted ammonium hydroxides can be used to effect hydrolysis. The base can be dissolved in water or a mixture of water with one or more water-soluble organic solvents. Examples of suitable water-soluble organic solvents include methanol, ethanol, propanol, ethylene glycol, propylene glycol, acetonitrile, dimethylformamide, and dimethylacetamide.
The base useful in the invention is typically an alkali metal hydroxide, most preferably sodium hydroxide. The concentration of base in the aqueous solution is not critical and depends on the base being used and the treatment temperature. In the case of sodium hydroxide, the concentration may range from 1 to 40% by weight. The temperature of the treatment is not critical, room temperature being preferred. Temperature ranges of 10 to 90° C. may be employed. Lower temperature is preferred with the higher concentrations of base. The article is exposed to the basic solution long enough to reduce its weight by from 1 to 30 percent, preferably by from 1 to 10 percent. The treatment time will depend on the concentration and temperature of the basic solution; the higher the concentration of the base solution, and the higher the temperature employed the shorter the time of treatment. Times as low as 2 to 30 seconds can be employed successfully. Optionally, the article is then washed with water to remove the bulk of the base solution.
Following the hydrolysis treatment, the article is acidified by treatment with strong mineral acid to a pH of less than or equal to the pKa of the carboxylate groups generated by the hydrolysis treatment. The article can be directly acidified with aqueous mineral or organic acids without the involvement of water washing. However, aqueous washing is preferred to minimize the use of acids. As used herein, the term “strong” mineral acid, means acids having a pH less than pH 2. Mineral acids useful herein include, for example, hydrochloric, sulfuric and phosphoric acids. Hydrochloric acid is most preferred. The time and temperature of the acidification step are not critical; times ranging from 2 seconds to 30 minutes at room temperature can be employed successfully.
Optionally, the article is again washed with water to remove the bulk of the mineral acid. The article may then be used directly in the next step, or may, optionally, be dried.
While not desiring to be bound by any particular theory, it is believed that the acidification below the pKa of the carboxylate groups, resulting in the formation of the free carboxylic acid group, greatly increases the rate and efficacy of the reaction of the carboxyl species with chitosan in the subsequent step.
Following the acidification step, the article is treated with chitosan. This comprises soaking or wetting the article with a solution containing a chitosan agent. The term “chitosan agent” as used herein means all chitosan-based moieties, including chitosan, chitosan salt, and chitosan derivatives. The solution comprising the chitosan agent may be aqueous. However, since chitosan by itself is not soluble in water, the chitosan may be solubilized in a solution. Solubility is obtained by adding the chitosan to a dilute solution of a water-soluble, organic acid selected from the group consisting of mono-, di- and polycarboxylic acids. This allows the chitosan to react with the acid to form a water-soluble salt, herein referred to as “chitosan salt.” Alternatively, “chitosan derivatives,” including N- and O-carboxyalkyl chitosan, that are water-soluble, can be used directly in water instead of chitosan salt. . The chitosan may also be dissolved in special solvents like dimethylacetamide in the presence of lithium chloride, or N-methyl-morpholine-N-oxide. Such solubilized chitosan solutions can be used in the present invention instead of aqueous solutions containing chitosan salt or chitosan derivatives.
Typically, the chitosan solution is an aqueous acetic acid solution, for example, an aqueous solution containing 2% chitosan and 0.75% acetic acid or 2% chitosan and 1.5% aqueous acetic acid. The time of treatment is typically 5 to 30 minutes. The temperature of the treatment is not critical, room temperature being preferred. After treatment with chitosan solution, excess solution may be allowed to drip out, or may be removed by wringing or spinning.
Optionally, the treated article is then dried via oven drying or a combination of ambient air drying and oven drying.
Articles prepared by the above methods exhibit antimicrobial properties. The term “antimicrobial” as used herein, means both bactericidal and fungicidal. In addition, the fibers and yarns processed herein exhibit favorable physical properties with respect to tenacity, elongation and hand-feel.
Said antimicrobial properties may, optionally, be further enhanced by treatment with soluble metal salts, for example, soluble silver salts, soluble copper salts and soluble zinc salts. The preferred metal salts of the invention are aqueous solutions of zinc sulfate, copper sulfate or silver nitrate. The metal salts are typically applied by dipping or padding a dilute (0.1 to 5%) solution of salt in water. The degree of enhancement depends on the particular metal salt used, its concentration, the time and temperature of exposure, and the specific chitosan treatment, that is, the type of chitosan agent, its concentration, the temperature, and the time of exposure. Examples 3, 4, 5, 6 and 7; FIGS. 7 , 8 , 9 , 10 and 11 ; and Table 1 demonstrate the effect of metal salts in the process of the invention.
Articles prepared by the above method of the invention also exhibit improved antistatic properties. Antistatic properties refer to the ability of a textile material to disperse an electrostatic charge and to prevent the buildup of static electricity. ( Dictionary of Fiber & Textile Technology , Hoechst Celanese Corp., Charlotte, N.C. (1990), p. 8)
A further optional post-treatment comprises applying a carboxyl-containing polymer to the chitosan treated article, or to the metal salt treated chitosan treated article. The term “carboxyl-containing polymer” as used herein means a polymer that contains carboxylic acid groups in side chains attached to the polymer backbone. The carboxyl-containing polymer, most preferably polyacrylic acid, is typically applied from a dilute aqueous solution by dipping or padding.
Any of the above described chitosan-treated articles, metal salt-treated articles or the carboxyl-containing polymer-treated articles, may benefit from a further chitosan solution treatment. Included within the scope of this invention are articles that, having received a first treatment with chitosan by the process of the present invention, are further subjected to one or more treatments with metal salt, carboxyl-containing polymer and/or additional chitosan in any order, with the proviso that the surface of the final article is treated with metal salt or a chitosan solution.
In a preferred embodiment, the process of the invention further involves heating the chitosan-grafted polyester-containing article to a temperature of from 35° C. to 190° C. under a nitrogen or ambient atmosphere for from 30 seconds to 20 hours, washing with deionized water and further drying the article at a temperature of 35° C. to 190° C. for from 30 seconds to 20 hours.
The articles of the present invention can also be produced in a continuous process. The process is illustrated by FIG. 20 of the drawings herein. Referring now to FIG. 20 , there is shown an apparatus for performing the following sequential steps of the invention:
(a) A feed station ( 2 ) on which is disposed a polyester-containing article ( 1 ) is provided. The feed station would typically comprise one or more feed rollers ( 10 ). (b) The article is drawn from the feed station through a first treatment station ( 4 ) wherein said article is exposed to a basic solution. The treatment stations herein would typically be immersion bath trays or tanks. (c) The article is optionally drawn from the first treatment station through a second treatment station ( 5 ) wherein the step (b)-treated article is exposed to water. Optionally, one or any number of draw rolls ( 11 ) may help guide the article between the treatment stations. Draw rolls such as draw roll ( 11 ) may be placed along any step of the continuous process as is commonly known in the art. (d) The article from the second treatment station is drawn through a third treatment station ( 6 ) wherein the step (c)-treated article is exposed to a strong mineral acid solution. (e) Optionally, the article from the third treatment station is drawn through a fourth treatment station ( 7 ) wherein the step (d)-treated article is exposed to water. (f) The article is then drawn through a fifth treatment station ( 8 ) wherein the step (d)- or step (e)-treated article is exposed to a solution comprising the chitosan agent. As discussed above, the chitosan agent is selected from the group consisting of chitosan, chitosan salts and chitosan derivatives. The treatment stations would typically be immersion bath trays or tanks. (g) Optionally, the step (f)-treated article is heated by a heater, such as a heater roll assembly ( 9 ) after it exits the chitosan treatment station. (h) The step (f)- or step (g)-treated article is then received on and accumulates on the take-up station ( 3 ). The treated article would typically be wound by means of a traversing guide ( 12 ) onto the take-up station ( 3 ) which is typically one or more cardboard or resin tubes to form spinning bobbins.
The feed station, treatment stations, heaters, and take-up components may be any convenient means known in the art for continuous treatment of fibers and yarns (see, for example, Ullmann's Encyclopedia of Industrial Chemistry , fifth Edition, Wolfgang Gerhartz, Executive Editor, Volume A10, VCH Verlagsgesellschaftg, Weinheim, Federal Republic of Germany (1987), “Fibers, 3. General Production Technology,” H. Lucker, W. Kagi, U. Kemp, and W. Stibal, pp. 511–566). The continuous process is particularly appropriate for treating polyester-containing fiber or yarn on a commercial scale.
The process and articles of the present invention do not employ crosslinking agents which makes the process more efficient and economical than other currently available processes requiring the use of crosslinking agents. The phrase “crosslinking agent” connotes the commonly used di- or tri-functional crosslinking agents known in the art. The carboxyl-containing polymers, e.g. polyacrylic acids, are not construed to be crosslinking agents in the context of the present invention.
The preferred articles of the present invention are in the form of fibers; fabrics, including wovens and nonwovens; filaments; films; and articles and constructs prepared therefrom.
The antimicrobial articles of the invention shall find application in uses such as apparel, including sportswear, activewear, intimate apparel, swimwear and medical garments; healthcare, including medical drapes, antimicrobial wipes, surfaces (counters, floors, walls), personal hygiene products and medical packaging; household articles, including fiberfill, bedding, window treatments and surfaces; and food processing/service, including packaging, absorbent antimicrobial pads for meat packaging, antimicrobial wipes and surfaces.
EXAMPLES
Materials and Methods
The following fiber-based materials were used in the following Examples. Woven and knit fabrics were also tested as outlined in the Examples.
1. Poly(ethylene terephthalate) (“2GT”) fiber, knit fabric and microfiber woven fabric, from E. I. du Pont de Nemours and Company (Wilmington, Del.). 2. Sorona® poly(trimethylene terephthalate) (“3GT”) yarn, 70 denier, 34 filament, round cross-section, made by E. I. du Pont de Nemours and Company (Wilmington, Del.).
The chitosan materials used in this study were obtained as commercially available from Primex Ingredients ASA, Norway under the trademark Chitoclear® chitosan and were used as purchased.
All Examples demonstrate the use of chitosan salt, i.e., chitosan dissolved in acetic acid as the chitosan agent of the invention.
Treated articles were tested for antimicrobial properties by the Shake Flask Test for Antimicrobial Testing of Materials, as follows:
1. A single, isolated colony from a bacterial or yeast agar plate culture was inoculated in 15–25 ml of Trypticase Soy Broth (TSB) in a sterile flask. It was incubated at 25–37° C. (using optimal growth temperature for the specific microbe) for 16–24 hours with or without shaking (selecting appropriate aeration of the specific strain). For filamentous fungi, sporulating cultures were prepared on agar plates. 2. The overnight bacterial or yeast culture was diluted into sterile phosphate buffer (see below) at pH 6.0 to 7.0 to obtain approximately 10 5 colony forming units per ml (cfu/ml). The total volume of phosphate buffer needed was 50 ml×number of test flasks (including controls). For filamentous fungi, spore suspensions at 10 5 spores/ml were prepared. Spore suspensions were prepared by gently resuspending spores from an agar plate culture that had been flooded with sterile saline or phosphate buffer. To obtain initial inoculum counts, final dilutions (prepared in phosphate buffer) of 10 −4 and 10 −3 were plated onto Trypticase Soy Agar (TSA) plates in duplicate. Plates were incubated at 25–37° C. overnight. 3. 50 ml of inoculated phosphate buffer was transferred into each sterile test flask containing 0.5 g of material to be tested. Also, control flasks of inoculated phosphate buffer and uninoculated phosphate buffer with no test materials were prepared. 4. All flasks were placed on a wrist-action shaker and incubated with vigorous shaking at room temperature. All flasks were sampled periodically and appropriate dilutions were plated onto TSA plates. The TSA plates were incubated at 25–37° C. for 16–48 hours and colonies were then counted. 5. Colony counts were reported as the number of Colony Forming Units per ml (cfu/ml). 6. The activity constant, At value, was calculated as follows: Δt=C−B, where Δt is the activity constant for contact time t, C is the mean log 10 density of microbes in flasks of untreated control materials after X hours of incubation, and B is the mean log 10 density of microbes in flasks of treated materials after X hours of incubation. Δt was typically calculated at 4, 6, or 24 hours and may be expressed as Δt X .
Stock phosphate buffer: Monobasic Potassium Phosphate 22.4 g Dibasic Potassium Phosphate 56.0 g Deionized Water volume increased to 1000 ml
The pH of the phosphate buffer was adjusted to pH 6.0 to 7.0 with either NaOH or HCl. The stock phosphate buffer was filtered, sterilized, and stored at 4° C. until use. The working phosphate buffer was prepared by diluting 1 ml of stock phosphate buffer in 800 ml of sterile deionized water.
Example 1
Preparation of Chitosan Grafted 2GT and 3GT Knit Standard Polyester Fabrics
Polyester fabrics (8 inch×9 inch; 3GT fabric weighing 21.8 g, 2GT fabric weighing 19.5 g) were soaked in 10% aqueous sodium hydroxide solution and gently shaken for 90 min. Each was then washed with water and soaked in 1 M aqueous hydrochloric acid solution for 30 min, washed with deionized water and dried in air for 1 h. Each was then immersed in 2 weight % aqueous chitosan solution (mol. wt. 75,000,) containing 1.5% acetic acid for 30 min, The chitosan used in Example 1 was food grade Chitoclear® chitosan (Primex Ingredients ASA, Norway). The degree of N-deacetylation of this sample was over 90% and this was ascertained by proton and carbon 13 NMR spectroscopy. The molecular weight of this sample was estimated using standard relative viscosity measurements as reported in the literature. The excess chitosan was allowed to drip, air dried for an hour and then dried at 85° C. for 16 h under nitrogen atmosphere. The weights of the chitosan-grafted fabrics were: 3GT, 24.06 g; 2GT, 21.32 g. The fabrics were then washed with water and dried at 80° C. for 16 h to give a 3GT sample weighing 23.3 g and a 2GT sample weighing 20.6 g (6.8 and 5.6% chitosan incorporation, respectively). These fabrics were tested for their antimicrobial efficacy as described above.
FIG. 1 shows the antimicrobial effect of chitosan grafted on 3GT knit fabric vs. Listeria monocytogenes ATCC 15313; the 3GT control is untreated fabric. FIG. 2 shows the antimicrobial effect of chitosan grafted on 2GT knit fabric vs. Klebsiella pneumoniae ATCC 4352; the 2GT control is untreated fabric. FIG. 3 shows the antimicrobial effect of chitosan grafted on 2GT knit fabric vs. Candida albicans ATCC 10231. FIG. 4 shows the antimicrobial effect of chitosan grafted on 3GT woven fabric vs. Staphylococcus aureus ATCC 6538.
Chitosan grafted onto 2GT and 3GT polyester fabrics demonstrated at least a 3-log reduction of the following microorganisms in 4–6 h:
Escherichia coli ATCC 25922 Escherichia coli ATCC 49106 (enterotoxigenic/enterohemorrhagic) Escherichia coli O157:H7 (enterotoxigenic/enterohemorrhagic) Salmonella cholerasuis ATCC 9239 Staphylococcus aureus ATCC 6538 Bacillus subtilis ATCC 6633 Enterococcus faecalis ATCC 29212 Klebsiella pneumoniae ATCC 4352 Listeria monocytogenes ATCC 15313 Listeria welshimeri ATCC 35897 Pseudomonas aeruginosa ATCC 27853 Candida albicans ATCC 10231 Acinetobacter sp. ATCC 14291 Micrococcus luteus ATCC 4698 Staphylococcus cohnii ATCC 49330 Staphylococcus hominus ATCC 27844
Example 2
Grafting of Chitosan Samples of Varying Molecular Weight onto 2GT Fabrics and the Evaluation of the Resulting Antimicrobial Properties
Chitosan samples with degree of de-N-acetylation of over 80% and mol. wt. in the range of 950,000 (Pfansteihl, U.S.A.), 630,000 (Sigma Chemical Company, U.S.A.), 290,000 (Kitomer, Canada), 104,000 (Chitoclear®, industrial grade, Primex Ingredients ASA, Norway), 83,000 (Chitoclear®, industrial grade, Primex Ingredients ASA, Norway), 74,000 (Chitoclear®, food grade, Primex Ingredients ASA, Norway), 39,000 (Chitoclear®, food grade, Primex Ingredients ASA, Norway), and 33,000 (Chitoclear®, food grade, Primex Ingredients ASA, Norway) were grafted onto polyester fabrics in order to evaluate the effect of chitosan molecular weight on the antimicrobial activity. A 1% solution of each commercial chitosan in 0.75% aqueous acetic acid was used in the grafting procedure as described in Example 1. As shown in FIG. 5 (2GT; E. coli ATCC 25922) and FIG. 6 (2GT; Staphylococcus aureus ATCC 29213), the process of this invention is operable with chitosans of a wide range of molecular weights.
Example 3
Preparation of Chitosan Grafted Fabrics Treated With Antimicrobial Salts
Chitosan grafted 3GT woven fabric (22.8 g), prepared according to the procedure of Example 1 was soaked in 2% aqueous silver nitrate solution for 30 min, extensively washed with water, and dried at 37° C. for 16 h. Weight of the resultant fabric was 23.0 g.
Similarly, chitosan grafted 3GT knit fabric (23.1 g), prepared according to the procedure of Example 1 was treated with 2% copper sulfate solution as described above to obtained copper doped fabric, (23.7 g).
As indicated by the results obtained, metal doping of chitosan-grafted polyester may be used to enhance antimicrobial activity. Silver nitrate ( FIG. 7 ), copper sulfate ( FIG. 8 ) or, by a similar procedure, zinc sulfate were used successfully as metal dopes. FIG. 7 demonstrates 3GT fabrics prepared with grafted chitosan with or without a silver nitrate dope vs. Salmonella cholerasuis ATCC 9239. FIG. 8 demonstrates 3GT fabrics prepared with grafted chitosan with or without a copper sulfate dope vs. E. coli O157:H7.
Chitosan grafted onto 2GT and 3GT polyester, followed by doping with metals has demonstrated at least a 3-log reduction of the following microorganisms, which are known to be more resistant to antimicrobials, in 4–6 h:
Escherichia coli ATCC 49106 (enterotoxigenic/enterohemorrhagic) Escherichia coli O157: H7 (enterotoxigenic/enterohemorrhagic) Salmonella cholerasuis ATCC 9239
Example 4
Preparation of Chitosan Grafted Fabrics After Treated With Various Concentrations of Silver Nitrate Solution
2GT knit fabrics in the form of (five) socks were soaked in water, the excess water drained, and then treated with 40% aqueous sodium hydroxide for 2 min. These socks were then extensively washed with water and soaked in 1M aqueous hydrochloric acid for 2 min, then washed with water. This was followed by immersing the socks in aqueous 1% chitosan (Chitoclear®, food grade, mol. wt. 74,000, Primex Ingredients ASA, Norway) solution containing 0.75% acetic acid for 2 min, then excess solution allowed to drain followed by drying the socks at 85° C. for 16 h under nitrogen. These dried samples were washed again with water and re-dried.
Four samples were, respectively, treated with aqueous 0.5%, 0.25%, 0.125%, and 0.0625% silver nitrate solution for 2 min., washed with water and dried at 45 C. for 16 h. The antimicrobial activity of these 4 samples and the “chitosan-only” control were then evaluated. FIG. 9 shows the antimicrobial effect of these 5 samples vs. Staphylococcus aureus ATCC 6538. Even the lowest concentration of silver nitrate (0.0625%) is very efficacious against the microbe Staphylococcus aureus ATCC 6538 and, as shown in FIG. 10 , just 0.01% silver nitrate dope was efficacious against microbes that can only be killed with chitosan-silver, such as E. coli O157:H7. It is postulated that the low concentration of silver works in synergy with the chitosan to achieve this level of efficacy.
Example 5
Preparation of Chitosan Grafted Fabrics Employing Various Times of Chitosan Treatment With and Without 0.1% Silver Nitrate Post Treatment
Samples of 2GT fibers were hydrolyzed and treated with 2% chitosan by the procedure of Example 4 except that the chitosan treatment time was 0.5, 1 or 2 minutes, respectively. Portions of each of these three samples were then treated with a 0.1% silver nitrate solution as in Example 4. FIG. 10 shows the antimicrobial effect of chitosan grafted on 2GT fabrics after these various hydrolysis times with and without the 0.1% silver nitrate post treatment vs. E. coli O157:H7.
Example 6
Wash Testing of Chitosan Grafted 3GT Fabrics (With and Without Silver Nitrate Post-Treatment)
Samples of 3GT chitosan grafted fabrics, with and without silver nitrate treatment (3GT samples prepared in Example 3 and Example 1, respectively), were subjected to five AATCC RA 88 “C” wash cycles. Table 1 below shows the results of an E. coli ATCC 25922 shake flask test on these washed 3GT fabrics. The Δt is the log reduction between the inoculum control and the test material. As shown in Table 1, all chitosan and chitosan+silver-treated fabrics reduced the viable population of E. coli ATCC 25922 by at least 3 logs after 4 h of exposure.
TABLE 1
3GT woven fabrics prepared with grafted chitosan with and
without a silver nitrate post treatment vs. E. coli ATCC 25922.
Fabric
Δt after 1 h
Δt after 4 h
3GT Control, unwashed
0.000
0.000
3GT Control, washed
0.267
0.160
3GT + Chitosan, unwashed
4.869
5.415
3GT + Chitosan, washed
2.313
3.813
3GT + Chitosan + Ag, unwashed
5.568
5.415
3GT + Chitosan + Ag, washed
5.568
5.415
Example 7
Testing of Antimicrobial Activity of Free Chitosan, Chitosan Grafted 2GT and Silver Nitrate Post-Treated Chitosan Grafted 2GT
Two pieces of scoured socks (5.56 g and 5.9 g respectively) of 2GT polyester fabrics were grafted with 2% chitosan solution as described in Example 1 to generate chitosan grafted fabrics (weight after grafting was 6.2 g and 6.6 g, respectively). This latter piece of fabric (6.6 g) was then soaked with 0.5% silver nitrate solution, washed with water and dried at 37° C. for 16 h. Weight of the dried fabric was 6.6 g. For comparative purposes, free chitosan powder was tested as is in the shake flask test.
FIG. 11 shows the antimicrobial activity of free chitosan, grafted chitosan and silver nitrate-treated grafted chitosan vs. Staphylococcus aureus ATCC 6538. Free chitosan demonstrates lower antimicrobial activity, which is more characteristic of a bacteriostat, compared to chitosan grafted onto polyester with or without silver nitrate post treatment.
Example 8
Multi-layer Grafting of 2GT Fabrics With Chitosan and Polyacrylic Acid
Four 2GT knit fabrics (samples A–D, 19.5, 18.8,19.5, 19.7 g, respectively) were grafted with chitosan as described in Example 1. Weight of the products A–D were 21.3, 20.4, 21.2, and 21.1 g, respectively.
Fabric samples A and B were dipped in 2% polyacrylic acid solution for 30 min, air dried and washed with water and then dried at 80° C. to give chitosan polyacrylic acid coated fabrics A′ (21.5 g) and B′ (20.6 g).
Part of fabric A′ (10.3 g) was treated again with 2% chitosan solution and dried at 85° C. for 16 h followed by washing with water and dried to give A″ (10.5 g). Another part of A′ (11.2 g) was dipped in 2% silver nitrate solution for 30 min, washed with water and dried at 37° C. for 16 h. to give A′″. Weight of A′″ was 11.02 g.
FIG. 12 shows the antimicrobial activity of 2GT+chitosan (A); 2GT+chitosan+polyacrylic acid (A″); 2GT+chitosan+polyacrylic acid+chitosan (A″), and 2GT+chitosan+polyacrylic acid;+silver nitrate (A′″) and three various controls vs. E. coli 25922.
Example 9
Chitosan Grafted Fibers Made in Commercial Prototype Equipment
The chitosan chemistry described in the above examples can be applied to fibers as well as fabrics using standard fiber processing equipment. The preparation of antimicrobial fibers by performing the caustic hydrolysis, acidification, and chitosan grafting steps in a package dyer, as well as by performing the caustic hydrolysis and acidification in a package dyer and the chitosan grafting step in a single-end sizer machine has been demonstrated.
FIG. 13 shows antimicrobial performance of 2GT fiber with grafted chitosan applied by processing in a package dyer vs. E. coli ATCC 25922. FIG. 14 shows the antimicrobial performance of 2GT fiber with grafted chitosan applied by processing in a package dyer and single-end sizer vs. E. coli ATCC 25922.
Example 10
Chitosan-Treated Bicomponent Fiber: 2GT/Lycra® Blend
Fibers of a Lycra® spandex/2GT blend (Lycra® spandex/2GT blend fiber containing 10% 10 denier Lycra® and 90% 150 denier Dacron® polyester, made by E. I. du Pont de Nemours and Company (Wilmington, Del.)) were treated with caustic as described in Example 1. The treated fibers were then passed through a chitosan solution in a single-end sizer as in Example 9. FIG. 15 shows the antimicrobial effect of the chitosan-treated fibers versus E. coli ATCC 25922.
Example 11
Chitosan Treatment of Yarns Commonly Combined with Polyester in Fabrics
Cotton yarn (having a yarn count of 30/1cc, commercially available from Parkdale Mills, Inc. (Gastonia, N.C.)), Soft White® 24 acrylic yarn ( 1/24 worsted count with a 1½″ cut, 100% open end spun yarn that has been waxed, made by Amital Spinning Corporation (New Bern, N.C.)), and Tactel® nylon 66 (30 denier yarn (commercially available from E. I. du Pont de Nemours and Company, Wilmington, Del.) were treated with caustic as described in Example 1. The treated fibers were then passed through a chitosan solution in a single end sizer as in Example 9. FIG. 16 shows the antimicrobial effect of the chitosan-treated yarns versus E. coli ATCC 25922.
Example 12
Chitosan-Treated Polyester/Rayon Nonwoven Fabric
Sontara® wipes comprising a 1:1 polyester/rayon nonwoven blend (commercially available from E. I. du Pont de Nemours and Company. (Wilmington, Del.) were treated as in Example 1, one sample with only the caustic treatment described therein and one with the complete chitosan grafting treatment. The antimicrobial effect of the chitosan grafting treatment versus E coli ATCC 25922 is seen in FIG. 17 .
Example 13
Chitosan-Treated Polyester/Cellulose Nonwoven Fabric
Sontara® wipes comprising a 1:1 polyester/wood pulp nonwoven blend (commercially available from E. I. du Pont de Nemours and Company, Wilmington, Del.) were treated as in Example 1, one sample with only the caustic treatment described therein and one with the complete chitosan grafting treatment. The antimicrobial effect of the chitosan grafting treatment versus E. coli ATCC 25922 is seen in FIG. 18 .
Example 14–18
(a) Preparation of Surface Primed 2GT Fibers
2GT fiber (150–200 g, 229 g) was passed at a rate of about 8 m/min through a series of solution trays containing, in turn, 10% aqueous sodium hydroxide, 1.0 M aqueous hydrochloric acid, and water. Excess solution was then stripped from the fiber with a sponge. The fiber was then dried by wrapping around a drum heated to about 130° C. The fiber was then wound using a tension winder followed by heat setting the fiber at 160° C. by wrapping around a heated roller at that temperature and winding at a speed at 60 m/min. Yield of the fiber was 218.7 g, a loss of 4.5 weight percent. This procedure demonstrates the hydrolysis conditions that cause weight loss of the fiber. The process resulted in the formation of carboxyl groups on the surface of the fiber as evidenced from the dying of the fiber with a blue dye specific for acidic groups.
(b) Preparation of 2GT Chitosan-Treated Fiber and Fabric
2GT fiber (150–200 g) was passed at a rate of about 8 m/min through a series of solution trays containing, in turn, 10% aqueous sodium hydroxide, 1.0 M aqueous hydrochloric acid, water, and a solution of chitosan (Chitoclear®, Primex Ingredients, Norway) in 1% aqueous acetic acid. The concentration of chitosan varied from 0.25 to 2 weight percent, as shown in Table 1. Excess solution was then stripped from the fiber with a sponge. The fiber was dried by wrapping around a drum heated to about 130° C. The fiber was then wound using a tension winder followed by heat setting of the fiber at 160° C. by wrapping around a heated roller at that temperature and winding at a speed at 60 m/min. In each case, the chitosan-treated fiber was tested with Orange II dye, and the orange color indicated chitosan was present on the surface of the fiber. A portion of fiber that had been treated with a 2% chitosan solution was made into a fabric and dyed with Orange II dye. The intense orange color indicated that chitosan was present at the surface of the fabric.
TABLE 2
Chitosan
Initial
Final
Weight
Concentration
Example
Weight (g)
Weight (g)
Change (%)
(weight %)
Surface
229
218.7
−4.5
0
primed
only
−4.5
14
207
231
11.6
2
15
141
154
9.2
1.5
16
165
174
5.5
1
17
119
133
11.8
0.5
18
216
237
9.7
0.25
Example 20
Preparation of Antimicrobial Chitosan-2GT/3GT Fibers
2GT/3GT bicomponent fiber from E. I. du Pont de Nemours and Company (Wilmington, Del.) was passed at a rate of about 8 m/min through a series of solution trays containing, in turn, 10% aqueous sodium hydroxide, 1.0 M aqueous hydrochloric acid, water, and a solution of 0.25% chitosan (Chitoclear®, Primex Ingredients ASA, Norway) in 1% aqueous acetic acid. This was followed by stripping the excess solution in the fiber with a sponge. The fiber was dried by wrapping around a drum heated to about 130° C. The fiber was then wound using a tension winder followed by heat setting of the fiber at 160° C. by wrapping around a heated roller at that temperature and winding at a speed at 60 m/min. Two samples were taken from different part of the fiber and submitted for antimicrobial evaluation. The antimicrobial effect of the chitosan grafting treatment versus E coli ATCC 25922 is seen in FIG. 19 . | This invention relates to antimicrobial polyester-containing articles and methodology for the preparation of antimicrobial polyester-containing articles utilizing chitosan and chitosan-metal complexes as the antimicrobial agent. | 51,503 |
CLAIM OF PRIORITY
[0001] The present application claims priority from Japanese application JP 2004-263195 filed on Sep. 10, 2004, the content of which is hereby incorporated by reference into this application.
FIELD OF THE INVENTION
[0002] The present invention relates to a delay locked loop (DLL) circuit, and in particular, to a delay locked loop circuit suitable for use in a digital predistortion circuit for compensating for nonlinear distortion occurring to an analog circuit (for example, a power amplifier), in a baseband, a digital predistortion type transmitter using the same, and a wireless base station.
BACKGROUND OF THE INVENTION
[0003] With the widespread use of cellular phones, it has lately become essential to make effective use of radio wave resources, and attention is being focused on CDMA, and OFDM as wireless communication systems high in frequency utilization efficiency. It is known that momentary maximum power at about 10 dB or greater against average transmission power occurs to a transmitter at a base station for these systems.
[0004] Meanwhile, a power amplifier of the transmitter at the base station has a property such that high efficiency is generally obtained at the time of a large output operation, but there occurs deterioration in linearity at that time because of output saturation. Since such nonlinear distortion causes a transmitted spectrum to spread, resulting in interference with other bands, a quantity of disturbing waves generated is strictly regulated by Wireless Telegraphy Act.
[0005] With the transmitter at the base station, it is regarded preferable from the viewpoint of equipment size and running cost to execute operation in a high-efficiency state by raising output amplitude of the power amplifier, however, with CDMA, and OFDM, operation at high efficiency has become difficult to execute because nonlinear distortion is prone to occur thereto.
[0006] As a method of overcoming such a problem as described, various method of linearizing the output of the power amplifier by use of distortion-compensating techniques have so far been developed, and as one of such methods, digital predistortion for executing compensation for distortion in a baseband has been well known. The conventional configuration of the digital predistortion includes a configuration wherein a delay unit is made up of an FIR type digital filter (refer to Patent Document 1).
[0007] [Patent Document 1] JP-A No. 189685/2001
[0008] FIG. 3 shows a configuration example of a digital predistortion type transmitter at a wireless base station, and FIG. 4 shows a configuration of a predistortion unit 303 by way of example.
[0009] In FIG. 3 , a transmission signal fed from a controller 300 is processed for coding by a modulator 301 to be subsequently subjected to bandwidth control by a baseband-signal-processing unit 302 , which outputs quadrature IQ signals Ii, Qi to be further processed for compensation for distortion by a predistortion unit 303 to be thereby converted into analog signals by a D/A converter 304 , and a quadrature modulator 305 executes conversion of frequencies of the analog signals into a radio frequency band, whereupon a power amplifier 306 amplifies power, thereby sending out radio waves into the air from an antenna 310 through an antenna sharing unit 309 . In this case, nonlinear distortion occurs to the power amplifier 306 at the time of a large output, which, however, can be deemed equivalent to a case where the nonlinear distortion is superimposed on the output of a linear amplifier 307 .
[0010] In order to effectively implement predistortion, it is necessary to accurately cancel out nonlinear characteristics of the power amplifier 306 by accurately grasping an amount of the nonlinear distortion that has occurred. Accordingly, transmission radio waves are converted in frequency to an IF band with the use of a mixer 311 to be subsequently converted into a digital signal by an A/D converter 312 , and the digital signal is demodulated by a digital quadrature demodulator 313 to be thereby fed back to the predistortion unit 303 . As for a configuration of a demodulation unit, a digital IF type excellent in demodulation precision has been described, however, various configurations other than that, including an analog quadrature modulator, are conceivable for adoption.
[0011] Next, referring to FIG. 4 , a configuration of the predistortion unit 303 is described hereinafter. In FIG. 4 , s delay unit 104 outputs signals Id, Qd obtained by delaying first input signals Ii, Qi by an integer (n) multiple of sample frequency. A subtractor 103 computes a difference between the signals Id, Qd, and second first input signals Ir, Qr. Based on a differential signal as obtained, an adaptive signal processor 102 controls a predistortor 101 so as to render the differential signal coming to zero. For adaptive signal processing, use is usually made of an algorithm for minimizing the square of an error, that is, distortion power, such as the least mean square algorithm, and recursive least square algorithm, based on the gradient method.
[0012] If nonlinear distortion has been accurately extracted by the subtractor 103 , reduction in the nonlinear distortion can be implemented as a result of the adaptive signal processing described as above. However, if the extraction of the nonlinear distortion is incomplete, a control error results even in a state where the nonlinear distortion is at zero because the differential signal is not eliminated. In other words, in order to implement effective predistortion, it becomes necessary that delay on a signal path from the predistortor 101 to the quadrature demodulator 313 have been corrected by the delay unit 104 .
[0013] However, while a delay quantity of the former does not always correspond to an integer multiple of the sample frequency since the same passes through analog elements, a delay quantity of the latter corresponds to nothing but the integer multiple of the sample frequency since the same is generated in a latch circuit. More specifically, if the delay quantity of the former is broken down into a component “n” corresponding to the integer multiple of the sample frequency, and a component “a” less than one sample frequency, the component “n” can be corrected, but it is difficult to correct the component “a.”
[0014] In Patent Document 1, there is disclosed a technology for correcting a delay quantity “a” less than one sample frequency. In this case, use is made of an FIR filter as means for causing the delay quantity less than one sample frequency to occur. In the case of this example, follow-up property thereof, against variation in delay time, is poor because delay time is decided prior to the start of a distortion-compensation operation. Accordingly, there is disclosed an example of creating a delay locked loop for controlling a clock phase of the A/D converter 312 .
[0015] With delay correction means using the FIR filter as described in the conventional technology, an amplitude characteristic becomes flat only in the case where a tap factor is “0 0 . . . .. 010 . . . .. 0 0”, and when delay is set to less than one sample frequency, there arises a problem that the amplitude characteristic intrinsically has waviness occurring thereto, thereby impairing accuracy in distortion extraction by subtraction. Further, since delay correction is implemented by means of the FIR, there is a tendency that relatively large and redundant delay (corresponding to not less than 16 samples in the case of an embodiment of the conventional technology) is added. thereby creating a factor for interfering with higher speed in adaptive signal processing.
[0016] Still further, there is a problem with the delay locked loop as described in the conventional technology in that there is the needs for analog components such as a D/A converter for controlling the clock of the A/D converter 312 , a smoothing filter, and a VCO in addition to those components shown in FIG. 3 . Furthermore, in addition to an increase in the number of the analog components, there is a problem with the performance thereof in that jitter is prone to occur to clock due to the effect of quantization noises of the D/A converter, and thermal noises of the VCO, and further, the retention capability of control voltage is low due to the effect of an offset voltage, thereby causing the delay locked loop susceptible to be out of sync at the time of no signal.
SUMMARY OF THE INVENTION
[0017] The invention has been developed in order to resolve the problem with the conventional technology as described above, and for example, a representative embodiment of the invention is as described hereunder.
[0018] That is, the invention provides a delay locked loop circuit which comprises: a variable delay element for receiving first input IQ signals; a subtractor connected to output terminals of the variable delay element, for receiving signals based on output signals of the variable delay element, and second input IQ signals; a delay comparator connected to the output terminals of the variable delay element, for receiving the output signals of the variable delay element; and a smoothing filter connected to an output terminal of the delay comparator, and to an input terminal of the variable delay element, for receiving and smoothing an output signal of the delay comparator, and outputting a smoothed signal to the variable delay element, in which either the first input IQ signals or the second input IQ signals are signals generated as a result of output IQ signals undergoing digital-to-analog conversion, and again undergoing analog-to-digital conversion after passing through an analog circuit, and delay control is implemented for checking distortion occurring to the output IQ signals due to the same passing through the analog circuit by means of the variable delay element.
[0019] In particular, with the use of an IIR filter as the variable delay element, the delay locked loop can be fully digitalized as an analog component is eliminated therefrom, so that it becomes possible not only to reduce the number of analog components, but also to avoid the problems of jitter and out-of-sync. Furthermore, since an FIR filter is not in use in this case, amplitude characteristic of the loop can be rendered fully smooth, and redundant delay can be suppressed to an extremely small magnitude.
[0020] Thus, with the delay locked loop according to the invention, delay between two kinds of signals can be corrected substantially exactly down to a minute delay less than one sample frequency.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a block diagram showing a first embodiment of the invention;
[0022] FIG. 2 is a block diagram showing a second embodiment of the invention;
[0023] FIG. 3 is a block diagram showing a configuration of a predistortion type transmitter at a wireless base station;
[0024] FIG. 4 is a block diagram showing a configuration of a predistortion unit;
[0025] FIG. 5 is a block diagram showing a configuration of a block of delay comparison and smoothing;
[0026] FIG. 6 is a block diagram showing a configuration example of an IIR filter (a lattice secondary all-pass type);
[0027] FIG. 7 is a diagram showing frequency characteristics in the case of the group delay characteristics being at the maximum smoothness;
[0028] FIG. 8 is a diagram showing the frequency characteristics in the case of the frequency characteristics being rendered wider in bandwidth ranging from f=0 to f=fs/4; and
[0029] FIG. 9 is a block diagram showing a third embodiment of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0000] First Embodiment
[0030] A first embodiment of the invention is described hereinafter with reference to the accompanying drawings. A configuration shown in FIG. 1 is the same as the configuration shown in FIG. 4 except that a delay comparator 106 , a smoothing filter 107 , and an IIR filter 105 are additionally provided. The delay comparator 106 outputs a signal according to a delay difference between signals Id, Qd, which are first input signals Ii, Qi, after delayed, and output signals If, Qf of the IIR filter 105 . The smoothing filter 107 outputs a signal P representing an output of the delay comparator 106 after removing high-pass random components thereof. The IIR filter 105 is a filter circuit acting on second input signals Ir, Qr, causing a delay quantity to undergo a change according to the signal P.
[0031] FIG. 5 shows respective configurations of the delay comparator 106 , and the smoothing filter 107 by way of example. First, on the basis of the reference signals Id, Qd, and the input signals If, Qf, respective momentary powers Wd, Wf are found. To find the respective momentary powers, it is sufficient to calculate the sum of the squares of the respective signals IQ. Subsequently, the momentary power Wd is kept delayed by one sample through a unit delay 203 , and the product of the momentary power Wd as delayed and the momentary power Wf is calculated with the use of a multiplier 206 . Separately from this, the momentary power Wf is delayed by two samples through unit delays 204 , 205 , and the product of the momentary power Wf as delayed, and the momentary power Wd as delayed is calculated with the use of a multiplier 207 . By calculating a difference between an output of multiplier 206 and an output of multiplier 207 , delay comparison based on correlation of the signals can be executed. However, with an output of the delay comparator 106 , a time average value contains not only delay information but also the high-pass random components attributable to the signals, so that the output is smoothed out by the smoothing filter 107 before outputting a signal P. As an example of a configuration of the smoothing filter 107 , use can be made of an integrator comprising an adder 209 , a unit delay 210 , and a constant multiplier 211 . As the output of the delay comparator 106 becomes zero at the time of no signal, an output of the smoothing filter 107 is retained at a constant value as a result of integration, and since the same is a digital circuit, retention capability thereof is perfect.
[0032] Now, an IIR filter is described hereinafter. Various configurations of the IIR filter are conceivable, and by way of example, there can be cited a lattice secondary all-pass filter as shown in FIG. 6 . The transfer function thereof is represented by expression (1), the amplitude characteristic thereof is constant regardless of frequency, and the group delay characteristic thereof varies depending on two parameters, that is, multiplier factors P 1 , P 2 :
Iout ( z ) Iin ( z ) = Qout ( z ) Qin ( z ) = P1 + P2 ( 1 + P1 ) z - 1 + z - 2 1 + P2 ( 1 + P1 ) z - 1 + P1z - 2 ( 1 )
[0033] In order to constitute a feedback loop, it is required that control be implemented by a single parameter P. Accordingly, functions P 1 =F 1 (P), P 2 =F 2 (P), based on single parameter P, are set up, and by imposing an appropriate restrictive condition on P 1 and P 2 , the two parameters are reduced to one parameter. Meanwhile, with the IIR filter, it is intrinsically impossible to obtain a linear phase characteristic (group delay smoothing characteristic), so that it is necessary to implement this by approximation. Accordingly, the restrictive condition described is decided in such a way as to give group delay smoothness. However, since various methods of deciding the same are conceivable depending on the method of the approximation, two cases are shown hereinafter.
[0034] If the restrictive condition as a first case is decided such that a group delay low-pass characteristic has the maximum smoothness, F 1 (P), and F 2 (P) are represented by expression (2):
F1 ( P ) = P ( P + 1 ) 8 - P ≅ 0.12 P + 0.12 P 2
F2 ( P ) = P ( P - 8 ) 8 + P 2 ≅ - 1.04 P - 0.03 P 2 ( 2 )
[0035] Shown in FIG. 7 is a frequency characteristic diagram obtained by plotting the group delay characteristics in this case, using the parameter P as a parameter. The group delay smoothness in a low-pass range is found extremely good, but an increase in frequency is accompanied by large variation in delay.
[0036] If a condition is added as a second case such that a group delay quantity at f=0 is equal to a group delay quantity at f=fs/4, F 1 (P), and F 2 (P) are represented by expression (3):
F1 ( P ) = P ( P + 1 ) 4 - P ≅ 0.23 P + 0.24 P 2
F2 ( P ) = P ( P - 4 ) 4 + P 2 ≅ - 1.08 P - 0.06 P 2 ( 3 )
[0037] Shown in FIG. 8 is a frequency characteristic diagram obtained by plotting the group delay characteristics in this case, using the parameter P as a parameter. Group delay is found somewhat wavy in a range of f=0 to f=fs/4; however, if such waviness is permissible, the frequency characteristics are deemed to be wider in bandwidth than in the first case. In either case, by varying the parameter P in a range of −1 to 0, the delay quantity can be continuously varied from one sample up to two samples.
[0038] Further, exact formulas of the functions of F 1 (P), and F 2 (P), respectively, are based on the four fundamental rules of arithmetic, and can therefore be implemented in a digital circuit, however, it need only be sufficient to execute multiplication and addition by employing polynomial approximation as described in expressions (2), and (3), thereby simplifying calculation. Furthermore, if relationships between corresponding functions are stored in a table, the exact formulas can be implemented even without execution of calculation.
[0039] With the present embodiment of the invention, the delay comparator 106 , the smoothing filter 107 , and the IIR filter 105 make up the delay locked loop, and by setting a delay quantity of the delay unit 104 to (n+1), timing of the output of the delay unit 104 can be coincided with that of the output of the IIR filter 105 , thereby enabling accurate extraction of a distortion component to be implemented by the subtractor 103 . Further, in contrast to the conventional technology, the delay locked loop is fully digitalized, so that the same is resistant to the effect of noises, and will not be out of sync at the time of no signal because the output of the smoothing filter 107 is retained without being affected by an offset. Furthermore, since the FIR filter is not in use, amplitude characteristic of the loop is theoretically smooth, so that redundant delay can be suppressed to an extremely small magnitude.
[0000] Second Embodiment
[0040] Next, a second embodiment of the invention is described hereinafter with reference to FIG. 2 . With a configuration shown in FIG. 2 , IIR filters 105 are in use in place of the delay unit 104 in FIG. 1 . A delay comparator 106 outputs a signal according to a delay difference between first input signals Ir, Qr, and output signals If, Qf of the IIR filters 105 . The smoothing filter 107 outputs a signal P corresponding to an output of the delay comparator 106 after removing high-pass random components thereof. The IIR filters 105 represent a filter circuit acting on second input signals Ii, Qi, causing a delay quantity to undergo a change according to the signal P. FIG. 2 shows a case where the IIR filters are provided in two stages, however, it is to be pointed out that the invention is not limited thereto. That is, the IIR filter in one stage may be provided or the IIR filters in not less than three stages (generally, in n-stages) (n: an integer not less than 1). If the IIR filters in the n-stages are provided, the sum of delay quantities of respective element IIR filters in the n-stages are obtained, as If, Qf, from the output terminal of the element IIR filter in the last stage.
[0041] The configuration of the present embodiment is not limited to a configuration shown in FIG. 2 , and may include various other variations. For example, FIG. 2 shows the configuration wherein the IIR filters 105 are disposed in front-end stages of a predistortor 101 , however, the present embodiment is not limited thereto, and the IIR filters 105 may be disposed in back-end stages of the predistortor 101 , or some thereof disposed in the front-end stages may be combined with others disposed in the back-end stages such that the IIR filters 105 may be divided in such a way as to be disposed at several locations.
[0042] With the present embodiment, a delay quantity along a signal path from the predistortor 101 to a subtractor 103 can be minimized while a variable range of the delay quantity can be rendered wider. Further, in contrast to the conventional technology, the delay locked loop is fully digitalized, so that the same is resistant to the effect of noises, and will not be out of sync at the time of no signal because the output of the smoothing filter 107 is retained without being affected by an offset. Furthermore, since the FIR filter is not in use, amplitude characteristic of the loop is theoretically smooth, so that redundant delay can be suppressed to an extremely small magnitude.
[0000] Third Embodiment
[0043] Now, a third embodiment of the invention is described hereinafter with reference to FIG. 9 . In FIG. 9 , in stead of using the IIR filters as variable delay elements, use is made of a quantizer 108 for binary-quantizing an output of a smoothing filter 107 , and a 0/1 delay switching unit 109 configured so as to be capable of selecting either 0-sample delay or one-sample delay (selectively switching therebetween) according to an output value of the quantizer 108 . A delay comparator 106 outputs a signal according to a delay difference between signals Id, Qd, corresponding to first input signals Ii, Qi, after delayed, and output signals If, Qf of the 0/1 delay switching unit 109 . The smoothing filter 107 outputs a signal P corresponding to an output of the delay comparator 106 after removing high-pass random components thereof. The quantizer 108 receives the signal P, and executes quantization for binarization of the same, thereby outputting a binary output value (for example, 0 or 1), corresponding to the signal P, to the 0/1 delay-switching unit 109 . The 0/1 delay-switching unit 109 causes a delay quantity of second input signals Ir, Qr, to undergo a change according to a binary input value (for example, 0 or 1) corresponding to the signal P, thereby outputting signals If, Qf.
[0044] With the present embodiment, since the delay quantity is insufficient at the time of 0-sample delay, and is excessive at the time of 1-sample delay, switching of the delay quantity is automatically implemented by the sigma-delta modulation that is well known as a feedback operation, so that it is possible to set a delay quantity “a” less than one sample on average. Accordingly, switching of the delay quantity can be executed at a sufficiently high speed in comparison with a signal bandwidth, thereby obtaining an advantageous effect equivalent to that of the first embodiment without use of the IIR filter.
[0000] Fourth Embodiment
[0045] Now, a fourth embodiment of the invention is described hereinafter with reference to FIG. 3 . The present embodiment is an example of a digital predistortion type transmitter (a transmission system at a wireless base station), to which the delay locked loop according the invention is applied. A transmission signal fed from a controller 300 is processed for coding by a modulator 301 to be subsequently subjected to bandwidth control by a baseband-signal-processing unit 302 , which outputs quadrature IQ signals Ii, Qi to be further processed for compensation of distortion by a predistortion unit 303 to be thereby converted into analog signals by a D/A converter 304 , and an quadrature modulator 305 executes conversion of frequencies thereof into a radio frequency band, whereupon a power amplifier 306 amplifies power, thereby sending out radio waves into the air from an antenna 310 through an antenna sharing unit 309 . For the predistortion unit 303 , use is made of any of the first to three embodiments described in the foregoing, or various variations thereof. In this case, nonlinear distortion occurs to the power amplifier 306 at the time of a large output, which, however, can be deemed equivalent to a case where the nonlinear distortion is superimposed on the output of a linear amplifier 307 .
[0046] In order to effectively implement predistortion, it is necessary to accurately cancel out nonlinear characteristics of the power amplifier 306 by accurately grasping an amount of the nonlinear distortion that has occurred. Accordingly, transmission radio waves are converted in frequency to an IF band through a mixer 311 to be subsequently converted into a digital signal by an A/D converter 312 , whereupon the digital signal is demodulated by a digital quadrature demodulator 313 to be thereby fed back to the predistortion unit 303 . As for a configuration of the demodulator, various configurations other than the one described are conceivable for adoption as in the case of the conventional demodulator.
[0047] With the present embodiment, the nonlinear distortion that has occurred to the power amplifier 306 can be accurately extracted by applying the delay locked loop according the invention to the digital predistortion type transmitter, so that it is possible to implement compensation for distortion, with few errors.
[0000] Fifth Embodiment
[0048] Further, a fifth embodiment of the invention is described hereinafter with reference to FIG. 3 . The present embodiment is an example of a wireless base station, to a transmission system of which the digital predistortion type transmitter according to the fourth embodiment of the invention is applied. The present embodiment is the same in configuration as the fourth embodiment except that a signal reception system is connected to the antenna sharing unit 309 . The antenna sharing unit 309 outputs a received signal delivered via the antenna 310 to the signal reception system while receiving a transmission signal amplified in power by the power amplifier 306 of the transmission system, and outputting the transmission signal to the antenna 310 . As for a specific configuration of the signal reception system, various well known forms can be used.
[0049] With the present embodiment, because the effect of signal delay is compensated for, and nonlinear distortion can be accurately extracted, control error in adaptive signal processing can be reduced, thereby enhancing linearity. Accordingly, since compensation for nonlinear distortion is appropriately implemented even at the time of a large amplitude, output at a large amplitude is enabled, thereby enabling operation in a high-efficiency state to be implemented. | Disclosed are a delay locked loop circuit capable of accurately extracting nonlinear distortion superimposed on an output of a digital predistortion type transmitter, the digital predistortion type transmitter, and a wireless base station using the same. The delay locked loop circuit comprises a variable delay element for receiving first input IQ signals Ir, Or, a subtractor for receiving signals Id, Qd based on output signals. If, Qf of the variable delay element, and second input IQ signals Ii, Qi, a delay comparator for receiving the output signals If, Qf of the variable delay element, and a smoothing filter for receiving and smoothing an output signal of the delay comparator, and outputting a smoothed signal to the variable delay element, in which delay control is implemented for checking distortion occurring to the output IQ signals due to the same passing through the analog circuit by means of the variable delay element. Either the first input IQ signals or the second input IQ signals are signals generated as a result of output IQ signals Io, Qo undergoing digital-to-analog conversion, and again undergoing analog-to-digital conversion after passing through an analog circuit. In particular, an IIR filter may be used for the variable delay element. | 28,692 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims benefit of priority to U.S. Provisional Patent Application Ser. No. 60/959,811 filed Jul. 16, 2007 and U.S. Provisional Patent Application Ser. No. 60/923,832, filed Apr. 17, 2007, which applications are hereby incorporated by reference in their entirety.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to surgical methods and devices therefor, including surgical access devices. Particularly, the present invention is directed to surgical access ports for use in endoluminal or transluminal procedures, such as through the human esophagus or lower gastrointestinal tract, and related methods.
2. Description of Related Art
A variety of devices are known in the art for assisting surgical procedures-including cannulas for accessing internal cavities of a patient, and other devices, such as endoscopes.
Endoscopy is a term for a range of medical procedures that allow a doctor to observe the inside of the body without performing major surgery. An endoscope (e.g., a fibrescope) is a long tube with a lens at the distal end and an eyepiece and/or camera at the proximal end. The end with the lens is inserted into a patient. Light is transmitted through the tube (via bundles of optical fibres) to illuminate the surgical site, and the eyepiece magnifies the area so the doctor can visualize the surgical site. Usually, an endoscope is inserted through one of the body's natural openings, such as the mouth, urethra or anus, but depending on the particular procedure, may require a small incision through the skin. Such procedures are often performed under general or local anesthetic. Specially designed endoscopes are used to perform simple surgical procedures, such as tubal ligation (“tying” of the female fallopian tubes); locating, sampling or removing foreign objects or tumors from the lungs or digestive tract; removal of the gallbladder; taking small samples of tissue for diagnostic purposes (biopsy).
A range of endoscopes have been developed for many parts of the body. Each has its own name, depending on the part of the body it is intended to investigate. For example, an arthroscope is inserted through a small incision to examine a skeletal joint. A bronchoscope is inserted down the trachea (windpipe) to examine the lungs. A colonoscope is inserted through the anus to examine the colon. A gastroscope is inserted down the esophagus to examine the stomach. A hysteroscope is inserted through the cervix to examine the uterus. A laparoscope is inserted through a small incision to examine the abdominal organs. A cystoscope is inserted via the urethra to examine the urethra and urinary bladder. Many of the foregoing procedures can be carried out with one or more instruments used in conjunction with an endoscope. Such procedures often also require an opening through which the endoscope and/or instruments can pass. Such working channels can be natural openings—e.g. the mouth and esophagus, or artificial openings such as an incision made in the abdomen of a patient.
Applicants recognize that current endoscopic systems suffer from various limitations, particularly when used in conjunction with certain medical procedures. Some endoscopes may be configured with an integral working channel. Such working channels are often small, and may or may not be suitable for a particular instrument to be inserted therethrough. Moreover, it can prove difficult to obtain good working instruments in very small sizes. Further, imaging through fibers can be limiting-often due to low resolution images. If an endoscope is provided with an imaging chip on a scope having a circular cross-section, this can restrict the size and quality of images obtained therefrom. Moreover, if insufflation is required for a particular procedure, insufflation through an endoscope is typically maintained with mechanical seals. Even state-of-the-art mechanical seals typically present difficulty for a surgeon due to substantial friction, which results in difficult manipulation and restricted instrument access.
Applicants recognize that with the foregoing problems in the art, there remains a need for improved visualization and access devices that allow for easier access and movement and better quality imaging. The present invention provides a solution for these problems.
SUMMARY OF THE INVENTION
The purpose and advantages of the present invention will be set forth in and apparent from the description that follows. Additional advantages of the invention will be realized and attained by the devices and methods particularly pointed out in the written description and claims hereof, as well as from the appended drawings. The present invention is directed to devices, as described hereinbelow, as well as to methods utilizing such devices.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied, the invention includes an access device adapted and configured to be inserted through a natural biological orifice is provided. The access device includes a body, a nozzle means and means for delivering a pressurized flow of fluid to the nozzle means. The body is configured and dimensioned to be inserted through a natural bodily orifice and has proximal and distal end portions and defines at least one lumen therethrough to accommodate passage of one or more surgical instruments. The nozzle means is operatively associated with the body for directing pressurized fluid into the lumen to develop a pressure differential in an area within a region within the lumen to form a fluid seal around the one or more surgical instruments passing therethrough.
In accordance with the invention, the body can be substantially rigid or substantially flexible, or include both rigid and flexible elements, as required. The access device can include at least one control element for manipulation of the curvature of the access device. Alternatively, two individual control elements can be used to control orthogonal motion—e.g., with respect to X and Y axes. Such control elements can further be provided in one or more opposing pairs. Such control elements can be, for example flexible or semi-rigid rods, wires or ribbons. Manipulation of the curvature of the entire access device can be controlled, or alternatively, the curvature of only the distal tip can be controlled, depending on the precise implementation.
One or more image sensors can be arranged in the distal end portion of the access device, which are adapted and configured to capture images of a region distal the distal end portion of the access device. If multiple image sensors are provided, they can facilitate stereoscopic imaging of the subject region. One or more working channels can be provided in the wall of the access device, and one or more of said working channels can be configured and adapted to provide irrigation to a surgical site. Alternatively or additionally, one or more of said working channels can be configured and adapted to provide drainage to a surgical site and one or more channels can be configured to allow a surgical instrument to pass therethrough.
One or more light sources can be arranged in the distal end portion of the access device, and adapted and configured to illuminate a region distal the distal end portion of the access device. Alternatively or additionally, illumination means can be provided in the wall of the access device.
Further, one or more guide elements adapted and configured to guide surgical instruments in the lumen of the access device can be provided. One or more pressure sensing channels can be arranged in the wall of the access device, and be configured and adapted to be in fluid communication with a surgical site.
Devices in accordance with the invention can be of any length desired or required. For example, the length of the body can be between about 30 cm and about 50 cm, depending on the precise application. A range of length between about 30 cm and 40 cm is particularly advantageous for a transesophageal access route for an endoluminal intra-gastric procedure—accessing a patient's stomach or duodenum. In alternate embodiments, the length of the body can be between about 40 cm and 50 cm, which range of length is particularly advantageous for transluminal access to internal organs via a trans-gastric route—that is, accessing a an organ through the wall of a patient's stomach. If desired, devices in accordance with the invention can be in the range of about 15 cm to about 20 cm for use as an anoscope and transanal access to the rectum, and can be up to about 160 cm in length for use as, or in conjunction with, a colonoscope, depending on the precise implementation. In accordance with one embodiment of the invention, a device provided with integral optics and illumination is between about 90 cm and 130 cm in length, preferably about 110 cm in length. Internal diameters of access devices in accordance with the invention can be any size that is practical for the application, but preferably range between about 10 mm and 20 mm, and in a preferred embodiment, between 15 mm and 18 mm.
Access devices in accordance with the invention can further comprise an integral image display provided in the proximal end portion thereof.
In accordance with another aspect of the invention, an insertion device is provided for inserting access devices in accordance with the invention. Such insertion devices can have a tip portion to facilitate insertion of the access device through a natural orifice. The tip can taper to a substantially blunt end and/or can include a dilating element. The tip portion can include at least one transparent region. The insertion device can be provided with illuminating means for illuminating a region distal the insertion device. Also, the insertion device can be configured and adapted to interface with an endoscope to facilitate guidance of the user during insertion. The insertion device can further include an integral lens arranged in a distal end portion thereof.
Further in accordance with the invention, a method of accessing an internal region of a body is provided. The method includes inserting through a natural body orifice an elongated body having longitudinally opposed proximal and distal end portions. The body defines at least one lumen configured and dimensioned to accommodate passage of one or more surgical instruments. The body further includes nozzle means operatively associated with the body for directing pressurized fluid into the lumen to develop a pressure differential in an area within a region within the lumen to form a fluid seal around the one or more surgical instruments passing therethrough. The method further includes the steps of delivering pressurized fluid to the nozzle means to create said pressure differential; and inserting one or more surgical instruments through the body to access the interior of the body.
In accordance with another aspect of the invention, an access device is provided which is adapted and configured to be inserted through an orifice. The access device includes a body, a nozzle means, means for delivering a pressurized flow of fluid to the nozzle means and at least one control element. The body is configured and dimensioned to be inserted through an orifice and has proximal and distal end portions and defines at least one lumen therethrough to accommodate passage of one or more surgical instruments, and is flexible in at least one region. The nozzle means is operatively associated with the body for directing pressurized fluid into the lumen to develop a pressure differential in an area within a region within the lumen to form a fluid seal around the one or more surgical instruments passing therethrough. The at least one control element is arranged within the body and is adapted and configured to effect a change in curvature of the at least one flexible region of the body. In accordance with the invention, the orifice can be a natural biological orifice, or alternatively can be formed from an incision made in the patient.
In accordance with still another aspect of the invention, a method for performing a cholecystectomy is provided. The method includes the steps of inserting a first access device through the esophagus of a patient and into the stomach, penetrating the stomach wall and extending the first access device through the stomach wall, inserting a second access device through the umbilicus of the patient, inserting an endoscope through the first access device, retracting the gallbladder, exposing the cystic duct and cystic artery, applying at least two dips on each of the cystic duct and artery, transecting each of the cystic duct and artery, dissecting and removing the gallbladder from the liver bed, and removing the gallbladder.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and are intended to provide further explanation of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute part of this specification, are included to illustrate and provide a further understanding of the method and system of the invention. Together with the description, the drawings serve to explain the principles of the invention, wherein:
FIG. 1 a illustrates a first embodiment of an access device in accordance with the invention, having a generally elliptical cross-section;
FIG. 1 b is a proximal end view of the embodiment of FIG. 1 a;
FIG. 1 c is a distal end view of the embodiment of FIG. 1 a;
FIG. 2 a illustrates a further embodiment of an access device in accordance with the invention, in which the wall of the device houses additional working channels;
FIG. 2 b is a cutaway view of a portion of the access device of FIG. 2 a , illustrating a fluid seal in accordance with the invention;
FIG. 2 c is a distal end view of the embodiment of FIG. 2 a , illustrating working channels and other features;
FIG. 3 a illustrates an access device in accordance with the invention, which is flexible and manipulable, in which instrument guides can be provided integrally with the access device, or can be provided in an attachable cap;
FIG. 3 b is a partial view of the access device of FIG. 3 a , illustrating surgical instruments inserted through the access device;
FIG. 3 c is a proximal end view of the access device of FIG. 3 a , illustrating an instrument guide provided therewith;
FIG. 3 d is a partial view of the distal end of the access device of FIG. 3 a , illustrating an insertion device inserted therethrough;
FIG. 4 a illustrates an access device in accordance with the invention having a proximal display, such as an LCD display;
FIG. 4 b is a distal end view of the access device of FIG. 4 a;
FIG. 5 illustrates a further embodiment of an access device in accordance with the invention, including control knobs which manipulate control elements provided within the access device;
FIG. 6 is an enlarged cross-sectional view of a distal end portion of an access device in accordance with the invention, through which an insertion device has been inserted;
FIG. 7 a illustrates a flexible access device, that is particularly configured and adapted for transanal insertion;
FIG. 7 b illustrates a rigid access device that is particularly configured and adapted for transanal insertion;
FIG. 7 c is a distal end view of the access devices of FIGS. 7 a and 7 b;
FIG. 7 d is a proximal end view of the access devices of FIGS. 7 a and 7 b , illustrating instrument guides provided thereon.
FIG. 8 is a side view of a further embodiment of an access device constructed in accordance with the invention having a distal end with open distal side portion;
FIG. 9 is an illustration of the access device of FIG. 8 inserted through a patient's esophagus into the stomach;
FIG. 10 is a side view of another embodiment of an access device constructed in accordance with the invention, with a distal end having a side-grasping feature with undulating grasping elements;
FIG. 11 is a partial view of the distal end of a variation of the embodiment of FIG. 10 , with straight grasping elements;
FIG. 12 illustrates three stages of an example procedure utilizing the access device of FIG. 10 ;
FIG. 13 a is a partial view of the distal end of a further embodiment of an access device constructed in accordance with the invention having internal steering elements;
FIG. 13 b is a cutaway view of the distal end of the access device of FIG. 13 a;
FIG. 14 is a schematic representation of a cholecystectomy in accordance with the invention; and
FIG. 15 are side and end views of a frangible tip in accordance with the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Reference will now be made in detail to select embodiments of the invention, examples of which are illustrated in the accompanying drawings.
The devices and methods presented herein may be used as surgical access ports, particularly for endoluminal or transluminal medical procedures. The devices described and set forth herein can incorporate any feature from the following U.S. patent applications and patents, which are each incorporated herein by reference in their entirety: U.S. patent application Ser. No. 11/517,929, filed Sep. 8, 2006 (U.S. Patent Publication No. US 2007/0088275, published Apr. 19, 2007), which is a continuation-in-part of U.S. patent application Ser. No. 10/776,923, filed Feb. 11, 2004 (now U.S. Pat. No. 7,338,473), which is a continuation-in-part of U.S. patent application Ser. No. 10/739,872, filed Dec. 18, 2003 (now U.S. Pat. No. 7,285,112), which is a continuation-in-part of U.S. patent application Ser. No. 10/441,149, filed May 17, 2003 (now U.S. Pat. No. 7,182,752). Each of the foregoing applications also claims priority to U.S. Provisional Application Ser. No. 60/461,149, filed Apr. 8, 2003, which itself is also hereby incorporated by reference in its entirety. The devices described and set forth herein can further incorporate any feature from U.S. patent application Ser. No. 11/544,856 (U.S. Patent Publication No. US 2008/0086167), and U.S. Provisional Application Ser. No. 60/850,006 both filed Oct. 6, 2006, which are also incorporated herein by reference in their entirety.
FIGS. 1 a - 1 c illustrate a first embodiment of an access device 100 in accordance with the invention. This embodiment has a generally elliptical cross-section, as can be seen at its proximal end 101 ( FIG. 1 b ). Further, this access device 100 , as embodied in FIGS. 1 a - 1 c , is sufficiently flexible to navigate a natural body orifice through which it is intended to be inserted. The access device 100 includes an insufflation input 120 a , and a pressure sensing channel having proximal and distal openings 110 a , 110 b , respectively. The body of the access device 100 includes a lumen 170 , and can be embodied so as to include manipulating elements 180 , such as wires, to effect curvature of the access device 100 , when desired. An image sensor 130 may be provided at the distal end region, as may be at least one light source 140 . In this embodiment it is contemplated that the at least one light source, may be one or more light-emitting diodes (LEDs), and that one or more CMOS, CCD or other small image sensors may be mounted at the distal end of the device and used as image sensors. Images can be transmitted to the external environment through conductive elements provided on or within the access device 100 , or can be provided wirelessly, such as by radio frequency transmission to a receiver. Alternatively, it is contemplated that the access device might not contain integrated optics and that known types of viewing devices may be inserted through the central lumen or a working channel of the access device for viewing purposes.
Devices in accordance with the invention can be of any length desired or required. For example, the length of the body can be between about 30 cm and about 50 cm, depending on the precise application. A range of length between about 30 cm and 40 cm is particularly advantageous for a transesophageal access route for an endoluminal intra-gastric procedure. In alternate embodiments, the length of the body can be between about 40 cm and 50 cm, which range of length is particularly advantageous for transluminal access to internal organs via a trans-gastric route—that is, accessing a an organ through the wall of a patient's stomach. If desired, devices in accordance with the invention can be in the range of about 15 cm to about 20 cm for use as an anoscope and transanal access to the rectum, and can be up to about 160 cm in length for use as, or in conjunction with, a colonoscope, depending on the precise implementation. In accordance with one embodiment of the invention, a device provided with integral optics and illumination is between about 90 cm and 130 cm in length, preferably about 110 cm in length. Internal diameters of access devices in accordance with the invention can be any size that is practical for the application, but preferably range between about 10 mm and 20 mm, and in a preferred embodiment, between 15 mm and 18 mm.
Additional features that can be incorporated into access devices in accordance with the invention include, but are not limited to having an outer cross-sectional shape ranging from circular, through an elliptical shape to near linear in shape.
With respect to the embodiment of FIGS. 1 a - 1 c , one or more fluid seals 120 b are provided to seal between instruments passing through the lumen 170 , and the wall of the lumen, in order to maintain pressure within an operative space. Various embodiments of access devices having fluid seals (or alternatively “air seals” or “pneumatic seals”) are set forth in the documents referenced above. Although mechanical sealing can additionally be incorporated into different embodiments of access devices described therein, as well as into those described in connection with the present invention, such mechanical seals can equally be absent, allowing substantially unencumbered movement of instruments through and within such access devices.
In accordance with the present invention the access device 100 of FIG. 1 or any access device set forth herein can be provided with a fluid seal, as described in the documents referenced above. The subject access devices can further include one or more of the following features: one or more endoscopes; one or more working channels; illumination capability; and/or the capability to be steered by a user. Incorporation of non-mechanical seals into endoluminal and transluminal access devices in accordance with the invention can allow for easier, safer procedures as well as new approaches to procedures.
Fluid seals in accordance with the invention can be embodied in a variety of suitable manners. Nozzles can be provided that are substantially annular in configuration, or alternatively, if desired, a plurality of discrete nozzle apertures can be defined in place one such annular nozzle. These discrete nozzle apertures can be arranged as necessary, about the wall of the access device, to form an effective barrier to proximal egress of insufflation gas from a surgical site. Such discrete nozzles can each be substantially round in shape, or alternatively can be oblong or another shape. The nozzles can be placed at regular intervals about the circumference of the lumen, can extend part way around, or can be spaced from each other in groups. If turbulence is desired, surface features such as protrusions, vanes, grooves, surface texture can be added in the path of fluid flow, as desired. Further, one or more nozzles or groups of nozzles can be provided in access devices in accordance with the invention, with such nozzles being located in one region, or in a plurality of regions along the length of the access device.
FIGS. 2 a - 2 c illustrate a further embodiment of an access device 200 , in accordance with the invention. The access device 200 includes an insufflation fluid input 220 a , which is in fluid communication with a fluid seal 220 b . The fluid seal may be positioned within the proximal housing of the device or may be positioned at any desired location between the proximal housing and the distal tip of the device. A lumen 270 serves as a working channel for passage of surgical instruments and the like, and is defined by the wall 275 of the access device 200 . The wall 275 itself also houses additional working channels, such as an irrigation port 260 , drainage port 261 and pressure sensing port 210 a . Additional ports can be used for additional functions, as desired or required. Optionally, illumination can be provided by way of one or more light sources, which can be provided directly in the wall 275 , or whose light can be transmitted through the wall 275 , to the distal end thereof by one or more fiber optic elements 250 . Further, one or more optional image sensors 230 can be provided in the wall 275 in order to capture images of a surgical site.
In accordance with the invention, the foregoing and following embodiments can be flexible or rigid, as desired or required. Further the foregoing and below-described access devices allow a user to pass a plurality of surgical instruments through a natural lumen into the human body. Such natural openings include, for example, the mouth and esophagus, the anus and rectum or vagina.
Entrance through such natural openings can provide access into the digestive tract without surgical incisions penetrating the external abdominal wall. Furthermore, gastrointestinal pressures can be maintained within the organ(s), such as the stomach, without any interference with inserted instruments which would typically be caused by mechanical seals used in a typical endoscope, colonoscope, trocar, cannula or other access systems. Moreover, manipulation of surgical instruments is less encumbered, as compared with more conventional devices having mechanical seals. The subject access devices suffer less from frictional resistance between inserted instruments and the access device. Reducing such interference and friction is advantageous, and may reduce torque and other forces transmitted from the inserted instrument through the access device to surrounding tissue, which can cause trauma and prolong healing and recovery. The access device may also allow crossing of paths of the inserted instruments, as when switching hands, without having to retract and then reinsert an instruments.
Endoscopic surgical or exploratory access via a transesophageal or transanal route can be intraluminal—that is, it can be used for accessing the natural lumen itself (e.g., the esophagus, stomach, rectum, colon), or can be transluminal, that is—used to access other anatomy through the wall of such structures. Such an approach can be referred to as Natural Orifice Transluminal Endoscopic Surgery™ (“NOTES”). Such access can allow for imaging, insertion of one or more surgical instruments, removal of a tissue specimen, or insufflation of the lumen (e.g., the stomach). For example, access to a patient's peritoneum can be achieved through an internal endoluminal route. Moreover, insufflation of the peritoneum is possible using access devices in accordance with the invention. The following is a sample list of minimally-invasive procedures that can be accomplished by surgeons operating through access devices as described herein:
Endoluminal Access to the Upper GI Tract
Reflux procedures, such as fundoplication
Obesity procedures, such as gastric restriction
Diabetes procedures such as duodenal bypasses
Gastric tumor removal
Endoluminal Access to the Lower GI Tract
Tumor removal
Diverticulum removal, repair
Transluminal Access Through Esophagus, Rectum or Vagina
All current abdominal and pelvic surgery such as:
Gallbladder Appendectomy Ovarian cysts Oophorectomy Sterilization Hernia repair
Devices in accordance with the invention can allow, in general, for new approaches to accessing anatomy. Any instrument inserted through the lumen of an access device equipped with one or more fluid seals in accordance with the invention will experience markedly reduced frictional resistance, due to replacement of mechanical seals with fluid seals. It may, at times, prove useful to include one or more mechanical valves, such as for example a duckbill valve or other so-called “zero seal” intended to seal the access device when no instrument is inserted therethrough. However, typically the number of such valves will be reduced if not eliminated, for every fluid seal that is used. Without mechanical seals protruding into a lumen of access devices in accordance with the invention, more space for instruments is available, while free insertion and movement of the instruments is not hampered by mechanical seals.
Further, gas, such as carbon dioxide, can be supplied to such fluid seals in a continuous manner—thereby insufflating an operative space while also sealing the operative space. Such a continuous flow of insufflation gas is distinct from prior systems, in that prior insufflation technologies operate in a cyclic manner—alternately insufflating and sensing pressure. Such systems do not allow for insufflation when pressure is being sensed. A further advantage to access devices in accordance with the invention, is that maintaining a pressure barrier in an access device, between an insufflated space and the surrounding environment without the use of elastomeric seals provides the capability for safe relief from pressure buildup from any possible system failures or sources of additional pressure. Additionally, bucking is reduced when operating using devices in accordance with the invention. Bucking is the phenomenon where a patient tightens his diaphragm while his abdomen is insufflated. This tightening dramatically increases pressure within the abdomen. Further, if used in laparoscopic procedure, fluid seals incorporated with devices constructed in accordance with the invention all use of open type instrumentation.
Additionally, access devices in accordance with the invention allow for more freedom in instrument design. Because contact seals are not required, instruments inserted through access devices in accordance with the invention do not need to conform to the shape and size of such mechanical seals. Accordingly, instruments having a non-symmetrical shape can be used, which may be more efficient and cost-effective, and multiple instruments can be inserted simultaneously to improve manipulation through the access device. Advantageously, the absence of mechanical seals reduces the likelihood of smudging of optical components of surgical instruments inserted through access devices constructed in accordance with the invention.
Moreover, devices in accordance with the present invention can be provided with various cross-sectional shapes, including, but not limited to circular, elliptical, or as set forth above, cross-sectional shapes that approach a linear morphology when not in use. If embodied in an elliptical shape, access devices in accordance with the invention advantageously allow insertion of instruments of various sizes, such as instruments having an oblong cross-section. An elliptical cross-section can also allow for insertion of the access device in regions of the anatomy that would otherwise not allow insertion of an access device having a round cross-sectional shape.
Surgical instruments that can be used through access devices in accordance with the invention include, but are not limited to rigid or flexible versions of the following, depending on the procedure: graspers, scissors, snares, staplers, ultrasonic imaging devices, ultrasonic cutting and/or coagulating devices, vessel sealing devices, RF devices, microwave energy delivery devices glue delivery devices and suturing devices.
Access devices in accordance with the invention can further incorporate various imaging technologies. One or more image sensors can be utilized for image acquisition, which sensors can be incorporated into an access device, for example at or near the distal end thereof. Alternatively, standard fiber optic imaging technology may be inserted through the fluid seal or may be incorporated into a wall of the access device, such that an objective (lens) is at the distal end portion of the access device, and an image sensor and/or eyepiece is provided elsewhere, such as at the proximal end thereof. Such imaging devices can be embodied so as to obtain still images, but video images can alternatively or additionally be obtained to allow for real-time guidance of a procedure, and can allow for guidance during insertion of the access device itself. Additionally, illumination can be provided in the subject access devices in the form of integrated fiber-optics, connected to an external light source and/or integrated sources of light, such as LEDs (light-emitting diodes) integrated into the distal end portion of the access device. Capability for infrared imaging for diagnostic purposes can further be provided, in the form of an optical sensor capable of capturing light in the infrared region, and additionally, if needed, an infrared light source.
FIGS. 3 a - 3 d illustrate a surgical access device 300 in accordance with the invention, which is flexible and manipulable, as with foregoing embodiments. One or more fluid seals 320 b are provided therein, to which fluid (such as compressed air or inert gas, or in the case of arthroscopic or other surgery which utilizes liquid, saline or other suitable biocompatible liquid) is supplied via a fluid input 320 a . A sensing input 310 is also provided, as described above in connection with other embodiments. If desired, instrument guides 385 (shown in the end view of FIG. 3 c ) can be provided integrally formed with the access device 300 , or in the form of an attached cap 380 ( FIG. 3 a ). As shown in FIG. 3 b , surgical or exploratory instruments 305 a , 305 b , 305 c pass through the guides 385 , and thereby are prevented from moving undesirably, or unnecessarily interfering with one another.
Further in accordance with the invention, an insertion device 390 can be provided, which is inserted into the access device 300 , prior to insertion in a patient. The insertion device 390 includes a tip 395 , which facilitates insertion into a patient. Tip 295 may be blunt or sharp, rounded or pointed or such other configuration as appropriate for the intended insertion. Tip 395 also may be transparent to provide optical viewing during or after insertion.
As illustrated in FIG. 4 a , a proximal display 489 , such as an LCD display, can be provided with access devices in accordance with the invention, such as access device 400 of FIGS. 4 a and 4 b . Such displays 489 can be integrated with respective access devices, or can be attached thereto in order to provide optimum viewing nearer the location in which the procedure is taking place, rather than on a display mounted far from the operating table. Such displays can provide high resolution direct images of the anatomy. In the embodiment of FIGS. 4 a and 4 b , the display 489 receives images from an image sensor 430 arranged in the distal end region of the access device 400 . If desired, video signals from the image sensor 430 can be additionally output to display monitors by one or more wired and/or wireless connections. Of course, images may alternatively or additionally be displayed on a traditional monitor in the vicinity.
As best seen in FIG. 4 b , illumination elements 451 may also be provided at the distal end region of the access device 400 , and can include light sources, such as light-emitting diodes (LEDs) or alternatively or additionally, fiberoptic conduits that deliver light from an external light source. It is preferable, generally, that such illumination elements 451 be capable of providing bright, controllable illumination and be relatively small in size. As can be seen in FIG. 4 b , the foregoing elements can be provided directly in a wall of the access device 400 , which has a lumen 470 , running therethrough, with openings 470 a ( FIG. 4 a ), 470 b at proximal and distal ends of the access device 400 , respectively.
The nature of access devices in accordance with the invention, particularly because fluid seals can be integrated therewith, allows the ability to use new flexible instruments of different shapes, geometries and mechanics. Such instruments might otherwise not be satisfactorily sealable with conventional sealing techniques. The absence of mechanical seals also can allow for passage of instrument drive and steering mechanisms, as well as for tissue manipulation, repair and/or retrieval.
FIG. 5 illustrates a further embodiment of an access device 500 in accordance with the invention. The access device 500 includes control knobs 581 , 583 , which manipulate control elements provided within the access device 500 . When the control elements are placed in tension, the access device will tend to bend toward that control element. Conversely, when a control element is placed in compression, the access device 500 , will tend to bend away from that control element. In the embodiment of FIG. 5 , two controls 581 , 583 control bending of the access device in two orthogonal directions, such as “X” and “Y” in a Cartesian coordinate system.
FIG. 6 is an enlarged cross-sectional view of a distal end portion of an access device 600 , in accordance with the invention, through which an insertion device 660 has been inserted. The insertion device 660 may receive an endoscope 670 therethrough, which views the insertion site through one or more transparent windows or lenses 665 . The lenses 665 can also be adapted to provide illumination to the insertion site. In this embodiment, the insertion device 660 may terminate in an elongate tip 661 , which may facilitate dilation of a natural orifice through which the insertion device 660 and access device 600 assembly pass during insertion. Further, the contour 663 of the insertion device provides a relatively smooth transition to the diameter of the access device 600 from that of the tip 661 .
FIGS. 7 a - 7 d illustrate rigid and flexible access devices 700 a , 700 b , respectively, that are particularly configured and adapted for transanal insertion into the rectum of a patient. Features for these embodiments can be any of those set forth in connection with foregoing embodiments, including but not limited to use with an insertion device, incorporation of one or more fluid seals or insufflation means and/or steerability (in the case of flexible access devices). Further, as illustrated in FIG. 7 d , which is a proximal end view of a cap for attachment to the access device 700 a , 700 b , instrument guides 785 can be provided. As best seen in the distal end view of FIG. 7 c , irrigation channels 781 , illumination capability 783 , visualization components, such as one or more image sensors 787 , or fiber optics to allow image transmission, and drainage capacity, such as in the form of drainage channels 789 can be incorporated. The foregoing elements can be arranged within the wall 775 of the access devices 700 a , 700 b , as with the embodiment described in connection with FIGS. 2 a - 2 c , for example. Additionally, an insertion device 790 can be utilized to facilitate insertion into the body of a patient.
FIG. 8 is a side view of a further embodiment of an access device 800 constructed in accordance with the invention. The access device 800 has a distal end 870 with open distal side portion 875 . This embodiment allows instrumentation to be oriented to act on the side as an alternative to or in addition to through a distal end aperture. This arrangement is particularly advantageous when performing a procedure on the wall of a passage, such as the esophagus, stomach or duodenum, for example. A wall of such passage can be sucked via vacuum or pulled by mechanical means into contact with the access device 800 to facilitate a procedure. When in contact with the access device 800 , steps including cutting, stapling and removal of tissue can be carried out. Vacuum can be applied in a number of ways, in accordance with the invention. Preferably, suction is applied directly through the access device 800 . A single pump can be provided, which is adapted and configured to both provide insufflation pressure to the access device 800 and to provide suction to the access device 800 . Use of a single pump allows for more streamlined surgical equipment and controls—reducing unnecessary clutter in the operating room and reducing cost by obviating a second pumping device. Naturally, if desired, separate pumps can be connected to the access device 800 , and selectively activated in order to switch between insufflation and suction. Alternatively still, a secondary suction device can be utilized—either inserted through a central internal lumen of the access device 800 or external thereto.
Additionally, the access device 800 can be flexible to allow manipulation through the anatomy of a patient, as seen in FIG. 9 . Moreover, the overall shape of the access device 800 can be preformed, as illustrated, so that the device has a tendency to revert to a shape that facilitates insertion and/or comfortable retention in the patient. The entire access device 800 , or a portion thereof, such as the distal end portion, can be steerable to aid insertion of the access device and procedures performed therewith.
A fluid seal can be provided in the proximal end portion 815 of the access device 800 , or additionally or alternatively at one or more other locations throughout the length of the access device 800 .
FIG. 10 is a side view of another embodiment of an access device 1000 constructed in accordance with the invention. The access device 1000 is similar to that of FIGS. 8 and 9 , but includes at its distal end 1070 , a side-grasping feature with undulating grasping elements 1071 . Alternatively, the side-grasping elements can be straight grasping elements 1171 as illustrated in FIG. 11 .
FIG. 12 illustrates the side grasping elements in closed, open and grasping positions, respectively. The grasping elements can be used to engage a wall of a passage, internal organ or other element, for example, to move the wall or steady the wall for another step, such as a puncture or incision. Actuation can be effected in any suitable manner. In accordance with one aspect of the invention, tension within the wall 1079 of the distal end 1071 is adjusted to effect closure or opening of the grasping elements 1071 . Such tension can be adjusted by way of, for example, shape-memory alloy ribs 1278 arranged within the wall of the distal end 1070 . Such ribs 1278 can have a first shape at normal room and/or body temperatures. The ribs 1278 can be electrically connected to a power source, such that when voltage is applied, resistive heating of the ribs 1278 effects a change in shape of the ribs to a second shape. Depending on the desired implementation, the normal state of the ribs can be open or closed.
Alternatively, the grasping elements 1071 can be actuated by providing one or more control elements (e.g., wires) terminating in a plurality of ends that terminate in or near the grasping elements 1071 , within the wall 1079 of the distal end 1071 . Accordingly, applying compression to such control cables will cause the grasping elements to close.
FIGS. 13 a and 13 b illustrate a distal end portion 1370 of a surgical access device constructed in accordance with the invention having a steerable distal end portion 1370 . Control elements 1310 , such as wires are provided within or adjacent the wall 1379 of the access device. The control elements 1310 are anchored in one or more locations 1320 to the wall of the access device. Although illustrated within the lumen 1340 of the access device, the control elements 1310 are provided with in the wall 1379 . Tension applied to one or more control elements 1310 effects a change in curvature of the distal end portion 1370 . In conjunction with applied rotation to the entire access device by a surgeon, navigation through the patient's anatomy is facilitated.
The present invention also relates to surgical procedures performed utilizing devices set forth herein. FIG. 14 illustrates an endoluminal and transluminal access device 1400 being used in a trans-gastric cholecystectomy (removal of gall bladder). As illustrated, the access device 1400 is inserted by way of the esophagus 1490 of a patient, into the stomach 1420 of the patient. Access is made by way of an incision through the wall of the stomach 1420 , into the abdominal cavity 1410 . An incision is made in any suitable manner, but preferably by an endoscopic cutting implement placed through the lumen of the access device 1400 , which induces coagulation, such as by electrocautery or ultrasonic vibrations.
Either preceding or following this step, a second access device 1450 is inserted through the navel or umbilicus 1411 of the patient. This mode of external access obscures any scarring that may occur. Naturally, the trans-esophageal entry of the access device 1400 carries no risk of visible scarring.
Prior to or upon entering the abdominal cavity 1410 , the cavity may be insufflated by way of the access device 1400 . Alternatively, the abdominal cavity can be insufflated by way of the second access device 1450 and/or still another element, such as a veress needle.
In the illustrated embodiment, a flexible endoscope 1405 is inserted through the transluminal access device 1400 . Any number of additional instruments that can physically fit through the lumen of the access device 1400 can be inserted therethrough, and the fluid seal formed by the access device 1400 will maintain a seal around the instruments. An entire cholecystectomy can be performed via this access device 1400 . At present it is more effective to close the incision made in the stomach wall by accessing the stomach 1420 from the outside, and for this reason, the second access device 1450 is used with a surgical stapler 1457 to close the incision made in the stomach. Therefore, the second access device 1450 is also used during the cholecystectomy. Through the channel of the second access device, an endoscope, grasper shears or any other necessary instrument can be inserted.
Upon severing the cystic duct, vascular tissue and connecting tissue, the gall bladder can be removed by either the transluminal access device 1400 or the second access device 1450 . If necessary, the gall bladder can be separated into smaller pieces for removal, as by a morcellator or the like.
In accordance with one embodiment of the invention, a method for performing a cholecystectomy includes the steps of:
Inserting a first access device in accordance with the invention through the esophagus of a patient and into the stomach; Penetrating the stomach wall and extending the first access device through the stomach wall; Inserting a second access device through the umbilicus of the patient; Inserting an endoscope through the first access device; Retracting the gallbladder with the at least one grasper; Exposing the cystic duct and cystic artery; Applying at least two clips on each of the cystic duct and artery; Transecting each of the cystic duct and artery with surgical scissors or another suitable instrument; Dissecting and removing the gallbladder from the liver bed; and Removing the gallbladder.
In accordance with this method, the second access device can have, for example, a diameter of 21 mm. The endoscope can be flexible and can have a diameter, for example, of about 10 mm. The cystic duct and artery can be exposed with dissectors, such as 5 mm dissectors. One or more graspers can be inserted through the second access device to manipulate the gallbladder. Clips can be applied with a 5 mm clip applier. The scissors can be 5 mm scissors, for example. Dissecting and removing the gallbladder can be accomplished with shears, such as ultrasonic shears. The gallbladder can be removed through the second access device. Alternatively, the gallbladder can be removed from the first access device, and can be removed from either access device whole or morcellated.
FIG. 15 illustrates one embodiment of a distal end portion of an access device in accordance with the invention. The access device of FIG. 15 includes a frangible tip 1510 that maintains sterility of the lumen of the access device during insertion through a cavity, such as the gastrointestinal tract, until a point when the tip is ruptured or intentionally cut. The frangible tip may have any shape, and may include lines of weakness 1513 , such as regions of decreased material thickness or score lines.
Having a sealed tip, instruments, such as endoscopes inserted through the access device benefit from a sterile path essentially the entire way to the surgical site. This reduces or eliminates any problems in sterilizing equipment, such as endoscopes with working channels. Advantageously, utilizing access devices in accordance with the invention eliminates the need for using endoscopes with integral working channels, because instruments can be inserted in parallel with the endoscope while maintaining a seal around all instruments. Even though sterility using access devices in accordance with the invention is enhanced as compared with simply inserting such instruments through a particular bodily opening, by including a sealed tip, sterility of a working channel is further enhanced.
Other types of tips or seals can be provided at the distal end of access devices in accordance with the invention, such as a removable cap, a sheath capable of being remotely withdrawn proximally, away from the distal tip or hinged hemispheric shutters, that function similarly to an eyelid and close over the distal opening of the lumen.
In accordance with the invention, transluminal access can be made through the rectum, colon, stomach (as illustrated in FIG. 14 ), esophagus or vagina, for example. Instruments that can be inserted through access devices in accordance with the invention include, but are not limited to dissectors, clip appliers, shears, automatic suturing devices, endoscopes, graspers, morcellators, suction tubes, electrocautery or coagulation devices, specimen retrieval tools, surgical staplers, as well as specialized tools for specific procedures.
Surgical procedures which may be performed with devices set forth herein, and in accordance with methods set forth herein include: cholecystectomy, appendectomy bariatric procedures, such as adjustable gastric banding (lap band), gastrectomy, such as sleeve gastrectomy, any of a variety of procedures to alleviate gastroesophageal reflux disease (GERD), tubal ligation, oophorectomy, nephrectomy, prostatectomy, colorectal procedures, hernia repair, gynecological resection, resection of the spleen, and splenectomy.
Such procedures, as well as others applicable in accordance with the invention, can mitigate damage caused by or aide recovery from such conditions as obesity, diabetes, gastroesophageal reflux disease (GERD), gallstones, appendicitis, colon disease, ideopathic thrombocytopenia purpura (ITP) and other diseases.
It should be noted that features described and/or illustrated in connection with one embodiment described herein can be combined with or substituted for other features described and/or illustrated in connection with any other embodiment set forth herein. Although a feature may be described in one particular embodiment, it should be understood that such a feature is not limited to being provided precisely in that manner or only in that embodiment.
The access devices and related methods of the present invention, as described above and shown in the drawings, provide, among other things, access devices with superior properties including the capability to provide substantially frictionless sealing of instruments passing therethrough. Endoluminal and transluminal procedures advantageously require less time for recovery than traditional procedures, among other benefits. It will be apparent to those skilled in the art that various modifications and variations can be made in the device and method of the present invention without departing from the spirit or scope of the invention. | An access device adapted and configured to be inserted through a natural biological orifice, and related surgical methods are provided. The access device includes a body, a nozzle means and means for delivering a pressurized flow of fluid to the nozzle means. The body is configured and dimensioned to be inserted through a natural bodily orifice and has proximal and distal end portions and defines at least one lumen therethrough to accommodate passage of one or more surgical instruments. The nozzle means is operatively associated with the body for directing pressurized fluid into the lumen to develop a pressure differential in an area within a region within the lumen to form a fluid seal around the one or more surgical instruments passing therethrough. | 54,024 |
BACKGROUND OF THE INVENTION
This invention relates to a positioning gear for moving a load suspended by at least one cable of a lifting system in the vertical direction.
In building large structures it is generally necessary to position large, complex and heavy members of the total structure by means of a hoisting crane, after which these structural members can be installed. In this process it is up to the crane driver to position the member as well as possible. However, since the crane driver is usually at a great height above the installation level, it is in practice not feasible for him to determine the correct position, in particular the correct height, of the member with respect to the structure. He usually receives, therefore, directions from an assistant at installation level, and generally the positioning of the structural member at installation level is carried out using manual force. This is time-consuming and requires manpower, and is therefore expensive.
SUMMARY OF THE INVENTION
It is now an object of the invention to permit an assistant at installation level to carry out all the positioning operations as soon as the crane driver has brought the member approximately to its intended position.
Another object is to provide a positioning gear in the form of an independently controllable unit for accurately positioning a load comprising an energy source, so that the positioning gear is able to work for a certain period without supply of energy from outside and which gear can be used at any location.
Still another object of the invention is to provide a positioning gear only requiring energy for moving a load upwardly, the moving of the load downwardly being effected by only the load.
This object is achieved by a positioning gear of the said type, whereby said gear comprises a controllable positioning element provided with a first attaching device for joining the element to a first cable section and a second attaching device for joining the element to a second cable section, following the first cable section, which can be joined to the load, said positioning element being able to vary the distance between said first and second attaching devices, said positioning element forming one movable assembly with an independent energy source or energy sources for operating the positioning element in a manner such that, after the positioning element has been joined to a cable, the entire assembly can be moved together with a load to be lifted or set down.
Such a gear makes it possible for an assistant at installation level to be able to determine relatively rapidly and accurately the position of the load by controlling the positioning gear.
This offers the great advantage that, in places where there is no room for placing trucks, cranes, and the like, which situation often occurs in towns with dense building and heavy traffic which must not be interrupted by closure, a load can nevertheless be set down in a simple and rapid manner at the desired position, which results in considerable savings in view of the costs of hiring a crane.
An independent energy source offers the great advantage that it is possible to work without making use of the normal electricity supplies which are often not directly available at such sites, as a result of which the employment of special electricity cables, which can easily be damaged, would be compulsory. The same problems arise if it is necessary to employ a supply line for supplying gaseous or liquid pressure medium, such as compressed air.
This construction also has the advantage that if the energy source is rechargeable, it can be kept small, and the recharging unit can be set down in the vicinity.
Advantageously, the positioning element comprises a single acting controllable working pressure medium cylinder with which a load can be set down in a simple manner at a desired position. According to a very advantageous embodiment, the working pressure medium cylinder together with a supply source of working pressure medium in a supply source of incremental pressure medium with the associated connecting lines forms one assembly which can be suspended via the working pressure medium cylinder in a cable.
In this case, the risk of the connecting lines being damaged is limited to a minimum.
In this case, the operating means for the entire assembly is expediently constructed as mechanically operable operating means such as with a traction cord.
The invention also relates to a method for placing a load at a desired position using a positioning gear according to the invention.
Other claims and many of the attendant advantages will be more readily appreciated as the same becomes better understood by reference to the following detailed description and considered in connection with the accompanying drawings in which like reference symbols designate like parts without the figures.
DESCRIPTION OF THE DRAWINGS
FIG. 1 shows diagrammatically a hoisting crane with the positioning gear according to the invention;
FIG. 2 shows diagrammatically an a large scale an embodiment of the positioning gear shown in FIG. 1;
FIG. 3 shows diagrammatically a system in which several lifting and positioning gears according to the invention are used and,
FIG. 4 shows diagrammatically another system in which several lifting and positioning gears are also incorporated.
DESCRIPTION OF PREFERRED EMBODIMENT
FIG. 1 shows a hoisting crane 28 having a crane jib 27 . Along the crane jib runs a travelling trolley 26 supporting a load 11 via a hoisting cable 10, a positioning gear 13 and cable sections 20 and 22. The force due to the weight of the load is compensated for by a counter-weight 29. The travelling trolley 26 and the hoisting cable 10 are operated by a crane driver 25 whose position is such that he can have a general overview of the positioning of the load. 24 shows a structure in which the load 11 is to be accurately positioned.
The crane drive 25 brings the load 11 approximately to its intended position. Then an operator 39 operates the positioning gear 13 by means of control devices 30 in a manner such that the load 11 is brought precisely to its position in the structure 24.
FIG. 2 shows diagrammatically a preferred embodiment of lifting and positioning gear according to the invention consists of a hydraulic cylinder.
This cylinder comprises a piston 31 with a rod 18. The cylinder 1 has an opening 23 for the supply and discharge of hydraulic working pressure fluid in the space 14; because a simple-acting hydraulic cylinder 1 is involved in this case, the supply and discharge are combined in one line 32. Also arranged in line 32 is a security valve 35' which operates in two directions to prevent the flow velocity of the fluid working pressure medium from being too high.
The line 32 leads to a pressure transformer 6, the pneumatic side of which is connected through a conduit 17, a valve 5 and a further conduit 16 to an energy supply source 8 of supplementary pressure medium, in the present embodiment a reservoir filled with gas under pressure, for example, a gas cylinder.
The line 33 leads to a supply reservoir 3 for working pressure fluid in the present exemplary embodiment a hydraulic-pneumatic oil reservoir of a conventional type.
Downstream of the energy supply source 8 for pressurized gas there is a reducing valve 9 which lowers the pressure of the gas from the supply source 8 to a usable level. Downstream of said reducing valve 9 there is a manually operable valve 5, controlled, for example, by a cord 37. The pressure transformer 6 of a conventional type converts the gas pressure from the source 8 into the pressure on the liquid working pressure medium with which the hydraulic cylinder 1 can be operated. The flow rate of the oil in the line 32 is determined by means of a rate regulating valve 7 which is preferably set beforehand. Although this may also be made controllable, it is preferable to set it beforehand in order to limit the number of operations performed by the operator in positioning the load to a minimum.
Downstream of the oil reservoir or accumulator 3 in the line 33 there is a valve 2 which can be used to allow or interrupt the flow of oil in the line 33. Between the valve 2 and the hydraulic cylinder 1 there is a rate controlling valve 4 by means of which the flow rate of oil in the line 33 can be determined. Connected in parallel with valve 4 is a spring-loaded non-return valve 34 being oriented in such a manner that working pressure medium or oil can only flow through it in the direction of the hydraulic cylinder 1. Said nonreturn valve 34 is useful in order to be able to feed oil rapidly into the cylinder 1 (raising of unloaded piston 31 after the load 11 has been put down) since the flow rate would otherwise only be determined by valve 4. Preferably, the valve 4 is set beforehand for the same reasons as have been mentioned for valve 7. Valve 2 is expediently operated by a cord 36, in which case, to fix the operations for opening and closing the valves, said cord 36 may be connected to cord 37.
A cable section 20 is attached via the device 19 to the housing of the cylinder 1, while a cable section 22 is attached to a device 21 mounted on the connecting rod 18 of piston 31. In the present embodiment, the cable section 20 is attached to the hoisting cable 10 of the crane 28 and the cable section 22 may be attached to the load 11.
The cylinder 1, the pressure transformer 6, the accumulator 3 and the energy supply source 8 and associated lines, and also shut-off valves 2 and 5 are expediently mounted on a frame thus forming a unit so that by incorporating cylinder 1 in the hoisting cable 10 all the other parts are also suspended by means of that frame. As a result of this, the risk of damage to any member when the gear according to the invention is being used is virtually eliminated.
The gear operates as follows.
In the initial state, the valve 2 is open and the piston 31 is in its highest position under the influence of the hydraulic pressure from the accumulator 3. A load 11 is attached to the cable section 22 which is jointed to the piston rod 18. When the hoisting is started, the outward stroke of the piston 31 with connecting rod 18 will take place under the influence of the weight of the load 11. It should be noted that the space 38 above piston 31 is not connected with any pressure fluid. Thus the working pressure cylinder 1 is only single acting. During this first phase of the hoisting and the lowering of the piston 31, a flow of oil takes place from the cylinder 1 towards the oil reservoir 3; the flow rate (and consequently the speed of movement of the load) is set in advance or controlled by means of the rate regulating valve 4. The flow of the oil to the reservoir 3 is stopped by closing the valve 2.
The load, which is not yet lifted in the initial stage, can now be raised by the crane 28 and brought near its intended position in the structure 24. Hereafter the intake stroke of the piston 31 with connecting rod 18 will take place under the influence of the pneumatic pressure from the gas reservoir 8. The valve 5 is opened, which produces a flow of gas under pressure to the pressure transformer 6 where the gas pressure is transmitted to the oil which will flow into the cylinder 1, as a result of which the piston 31 plus the load is moved upwards. This movement is stopped by closing the valve 5.
After the load has been positioned at the desired place, and the load is no longer attached to the cable section 22, the intake stroke of the piston 31 with connecting rod 18 is effected by opening the valve 2 and consequently bringing about the connection between the oil reservoir 3 and the cylinder 1. Due to the pneumatic pressure in the reservoir 3, oil flows from oil reservoir 3 to the cylinder 1, as a result of which the unloaded piston 31 is forced upwards.
Thereafter a new load may then be attached again to the cable section 22 and the lifting and positioning gear is again ready for use.
The operating devices described above (the valves 2 and 5, the rate regulating valves 4 and 7) are connected in a known manner to control devices by means of which the operator is able to operate the lifting and positioning gear. Preference is given to mechanical operation of the valves 2 and 5, while the rate regulating valves are expediently set beforehand and are not regulated during the operation of the gear.
FIG. 3 shows a use in which the load 11 has an appreciable surface area. The diagrammatically shown hoisting cable 10 divides up into two suspension cables 12 which divide up in turn into follow-on suspension cables 15. Lifting and positioning gear 13 according to the invention is located in one of the suspension cables 12 and in one of the follow-on suspension cables 15. This makes a more accurate positioning of the load 11 possible. Said lifting and positioning gears may each be connected separately to control devices 30, but they may also be connected to common control devices 30 so that one operator is able to operate the two lifting and positioning gears 13 together.
It is clear that several lifting and positioning gears according to the invention may be connected both in series and in parallel.
FIG. 4 finally shows yet another embodiment in which a hoisting cable 10 divides up into two follow-on cables 15a which support a supporting beam 38. In each of the follow-on cables 15a, positioning gear according to the invention is incorporated.
In order to be able also to rotate the load 11, the supporting beam 38 is connected via a follow-on cable 15b and positioning gear 13 incorporated therein to an upper face 11' of the load 11. At the other end of the beam 38, another follow-on cable 15c is fitted which divides up into two cables 15d, 15e which are connected to side faces 11" and 11"'. Positioning gears 13 are also incorporated in the cables 15d and 15e. | Positioning device to be incorporated as a controllable coupling element between a load and the cable of a hoisting apparatus. The element includes a hydraulic cylinder connected to a hydro-pneumatic transformer and to a hydro-pneumatic reservoir. The transformer is connected to a source of pressurized gas through a first valve, a second valve being provided in the line from the cylinder to the reservoir. The cylinder, the transformer, the pressurized gas source, the reservoir and both valves are mounted in a common frame, both valves being operable from a distance. | 14,228 |
RELATED APPLICATIONS
The present application is a continuation-in-part of application PCT/EP2011052890, filed on 28 Feb. 2011, in Europe, and published as WO 2012116721 A1.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This application relates to hearing aids. More specifically, it relates to a method for driving a digital output stage of a hearing aid. It also relates to a hearing aid configured for employing the method.
In this context, a hearing aid is defined as a small, battery-powered device, comprising a microphone, an audio processor and an acoustic output transducer, configured to be worn in or behind the ear by a hearing-impaired person. By fitting the hearing aid according to a prescription calculated from a measurement of a hearing loss of the user, the hearing aid may amplify certain frequency bands in order to compensate the hearing loss in those frequency bands. In order to provide an accurate and flexible amplification, most modern hearing aids are of the digital variety.
Contemporary digital hearing aids incorporate a digital signal processor for processing audio signals from the microphone into electrical signals suitable for driving the acoustic output transducer according to the prescription. In order to save space and improve efficiency, some digital hearing aid processors use a digital output signal to drive the acoustic output transducer directly without performing a digital-to-analog conversion of the output signal. If the digital signal is delivered to the acoustic output transducer directly as a digital bit stream with a sufficiently high frequency, the coil of the acoustic output transducer performs the duty as a low-pass filter, allowing only frequencies below e.g. 15-20 kHz to be reproduced by the acoustic output transducer. The digital output signal is preferably a pulse width modulated signal, a sigma-delta modulated signal, or a combination thereof.
The most recent generations of hearing aids also incorporate a tiny radio receiver for the purpose of receiving radio signals intended for the hearing aid circuitry. Typical uses of such a radio receiver are remote controlling volume and program settings from a wireless remote control carried around by the hearing aid user, streaming of audio signals from an external source such as a television set, a compact disc player or a mobile telephone, wireless programming of the hearing aid by a hearing aid fitter according to a prescription, thus eliminating the need for cumbersome wires and fault-prone electrical contacts between the fitting equipment and the hearing aid, or synchronization signals from another hearing aid. The radio receivers employed for this purpose must be physically small, have modest power requirements, and perform reliably within the intended range of the transmitter used.
An H-bridge is an electronic circuit for controlling inductive loads such as electric motors or loudspeakers. It operates by controlling the direction of a flow of current through a load connected between the output terminals of the H-bridge by opening and closing a set of electronic switches present in the H-bridge. The switches may preferably be embodied as semiconductor switching elements such as BJT transistors or MOSFET transistors. This operating principle permits a direct digital drive output stage to be employed in order to enable a suitably conditioned digital signal to drive a loudspeaker directly, thus eliminating the need for a dedicated digital-to-analog converter and at the same time reducing the power requirements for the output stage.
A sigma-delta modulator is an electronic circuit for converting a signal into a bit stream. The signal to be converted may be digital or analog, and the sigma-delta modulator is typically used in applications where a signal of a high resolution is to be converted into a signal of a lower resolution. In this context, a sigma-delta modulator is used for driving the H-bridge output stage in the hearing aid.
The diaphragm of a loudspeaker has a resting or neutral position assumed whenever no current flows through the loudspeaker coil and two extreme positions assumed whenever the maximal allowable current flows in either direction through the loudspeaker. By applying a sufficiently fast-changing bit stream from an H-bridge represented by positive and negative voltage impulses to the loudspeaker terminals, any position between the two extreme diaphragm positions of the loudspeaker may be attained. The higher the number of positive impulses in the bit stream is, the more the loudspeaker diaphragm will move towards the first extreme position, and the higher the number of negative impulses in the bit stream is, the more the loudspeaker diaphragm will move towards the second extreme position. Due to the low-pass filtering effect of the loudspeaker coil, no audible switching noise will emanate from the loudspeaker when driven in this way, provided the switching period of the bit stream is well above the reproduction frequency limit of the loudspeaker. Thus, a digital bit stream may control a loudspeaker directly.
2. The Prior Art
Digital radio receivers, such as the kind disclosed in WO-A1-09/062500, are especially useful, as they require very little power while maintaining a comparatively high selectivity in the reception. Other types of radio receivers may be employed, but the limited power available in a hearing aid puts a severe restriction on the selectivity, and, as a consequence, the obtainable range and reliability of the radio receiver. A remote control transmitter for use with a hearing aid has a desirable range of approximately one meter while an internal transmitter in another hearing aid has a desirable range of roughly thirty centimeters. The remote control transmitter is capable of issuing various commands to the hearing aid such as program selection and volume control, and also of performing streaming of a digitally represented audio signal to the hearing aid, thus being highly dependent on the existence of a reliable transmission link from the transmitter to the receiver. A pair of hearing aids having a set of transmitters and receivers may have the capability to exchange central parameters relating to the signal processing in the hearing aids apart from program selections and volume settings. This capability is also dependent on the presence of a reliable transmission link between the two hearing aids.
From EP-B1-1716723 is known a digital output stage for a hearing aid, said output stage comprising a sigma-delta converter and an H-bridge for driving an acoustic output transducer for a hearing aid. The output stage is denoted a three-level output stage because it is capable of delivering a bit stream consisting of three individual signal levels to the acoustic output transducer. In the following, these levels are denoted “+1”, “−1” and “0”, where “+1” equals the maximum positive voltage across the acoustic output transducer, “−1” equals the maximum negative voltage across the acoustic output transducer, and “0” equals no voltage. This utilizes the fact that a positive voltage pulse makes the diaphragm of the acoustic output transducer move in one direction, and a negative voltage pulse makes the diaphragm of the acoustic output transducer move in the other direction. By delivering a clocked bit stream consisting of “+1”-levels and “−1”-levels interspersed with “0”-levels as voltage pulses to the acoustic output transducer, any position deviation within the confinements of the mechanical suspension of the acoustic output transducer diaphragm may thus be obtained, as the loudspeaker coil acts as an integrator of the voltage pulses. The digital output stage of the prior art generates the “0”-level by applying a “+1”-level and a “−1”-level simultaneously to both terminals of the acoustic output transducer.
This way of generating the “0”-level for the acoustic output transducer has the advantages of being very easy to implement, as no extra components are needed to provide the “0”-level, and to save power, as the “0”-level uses no extra current and the provision of three separate levels effectively doubles the possible voltage swing across the acoustic output transducer. However, it also has some inherent drawbacks, which will be explained in greater detail in the following.
The “+1”-levels and “−1”-levels both generate differential voltages over the wires and terminals of the acoustic output transducer. This is not the case with the “0”-level. With the “0”-level, both wires carry the same voltage simultaneously, and since this is a voltage rapidly switching between the “+1”-level and “−1”-level it radiates more common mode signal energy to its immediate surroundings. This radiation results in increased crosstalk to nearby circuitry such as telecoils or wireless transmission receiver coils typically present in the hearing aid. Since this crosstalk has frequencies above 1 MHz, it does not possess a problem to a nearby telecoil, which may usually be found in a hearing aid, since a telecoil is configured to convey frequencies below 8-10 kHz. A wireless receiver coil, however, inevitably suffers a very considerable reduction in its signal-to-noise ratio from the capacitive interference signal induced by this crosstalk phenomenon, often to a degree where reliable signal reception becomes impossible.
This capacitive interference emanates mainly from electrically exposed parts of the output circuit, primarily the wires connecting the output pads of the electronic circuit chip of the hearing aid to the input terminals of the acoustic output transducer. It is not possible to shorten these wires further for mechanical reasons, but some reduction in the capacitive coupling between these wires and sensitive electronic circuits in the vicinity may be achieved by twisting the wires and keeping them physically close together.
The voltage pulses from the H-bridge output stage of the hearing aid are essentially presented to the output transducer as a square wave signal having a frequency of 1-2 MHz, and the resulting switching noise components from the “0”-levels generated in this manner may thus disturb the operation of electronic circuits sensitive to capacitive interference in this frequency range, such as a radio receiver. In cases where the afflicted electronic equipment incorporates a wireless remote control receiver in the hearing aid the problems caused by electromagnetic interference are exceptionally severe, as the effective operating range of the wireless remote control is limited considerably by the capacitive interference emanating from the output stage, excluding the remote control signals from proper reception.
WO-A1-03/047309 discloses a digital output driver circuit for driving a loudspeaker for a mobile device such as a hearing aid or a mobile phone. The digital driver circuit comprises an input, a modulator and a three-level H-bridge and is integrated into the loudspeaker enclosure in order to shield the driver circuit from electromagnetic interference and to keep the wires connecting the driver output to the loudspeaker short. The driver circuit further comprises a feedback circuit connected to the loudspeaker for regulating the supply voltage for the driver circuit.
An output driver integrated into a loudspeaker, such as described by the teachings of WO-A1-03/047309, is not interchangeable with dynamic standard loudspeakers of the kind used in hearing aids. If, for example, a hearing aid housing and circuitry may be adapted for use with a range of different loudspeakers having different impedance values, e.g. for treating different degrees of hearing loss, a loudspeaker having an integrated output driver would not be well suited for this configuration. Hearing aids configured for being used with receiver-in-the-ear (RITE) loudspeakers would also be impractical to implement using this method. In cases where this type of flexibility is desired, long wires between the output stage terminals of the hearing aid circuit and the terminals of the loudspeaker of the hearing aid are unavoidable. An extra set of long wires for the signal from the loudspeaker to the feedback circuit would also be required by the prior art output driver, which would further increase the capacitive interference noise.
The invention, in a second aspect, provides a method of driving an output stage for a hearing aid, said hearing aid having at least one input transducer, an analog-to-digital converter, a digital signal processor, a sigma-delta modulator, a first quantizing block, a second quantizing block, a decoder, an H-bridge output converter, an acoustic output transducer, a timer, a controller and a radio receiver, the radio receiver having an idle mode of operation and a listening mode of operation, said method comprising the steps of generating a driving signal in the sigma-delta modulator based on an output signal from the digital signal processor, processing, in the first quantizing block, using the sigma-delta modulator output signal to generate a first bit stream adapted for defining two discrete levels, processing, in the second quantizing block, using the sigma-delta modulator output signal to generate a second bit stream adapted for defining three discrete levels, the controller using the timer to execute a control sequence for enabling the decoder to select one bit stream among the first and the second bit streams and control the operating mode of the radio receiver, the decoder selecting the first bit stream whenever the radio receiver is in the listening mode, the decoder selecting the second bit stream whenever the radio receiver is in the idle mode, and providing a drive signal for the H-bridge output converter based on the selected bit stream.
This method of driving an output stage of the H-bridge variety for a hearing aid achieves that the power efficiency of an output stage operating with three levels is maintained as closely as possible while minimizing the problems caused by the interference also associated with a three-level output stage.
By taking the operating mode of the radio receiver into account when selecting the operating mode of the sigma-delta modulator, the H-bridge output converter is driven in a three-level mode whenever the radio receiver is in the idle mode, i.e. when it is not receiving any signals. In this case, power consumption is reduced by driving the H-bridge output converter in a three-level mode. Whenever the radio receiver is in the listening mode, the H-bridge output converter is driven in a two-level mode. In this case, the power consumption is increased somewhat, but the interference associated with driving the H-bridge output converter in the three-level mode is reduced.
In a preferred embodiment, the controller enables the radio receiver to enter the listening mode periodically, e.g. twenty times per second, in turn causing the H-bridge output converter to operate in the two-level mode for the duration the radio receiver is in the listening mode. The duration of the listening mode period may be relatively short, e.g. ten milliseconds, unless the radio receiver detects a radio signal within the listening mode period. Otherwise, the radio receiver may reenter the idle mode, in turn causing the H-bridge output converter to operate in the three-level mode again. However, if the radio receiver detects the presence of a radio signal within the listening mode period, reentrance by the radio receiver to the idle mode is suppressed until no radio signal has been detected for the duration of a predetermined period, e.g. a tenth of a second. Then the radio receiver reenters the idle mode, thus forcing the H-bridge output converter to operate in the three-level mode again.
The invention, in a second aspect, provides a hearing aid having at least one input transducer, an analog-to-digital converter, a digital signal processor, a sigma-delta modulator, a first quantizing block, a second quantizing block, a decoder, an H-bridge output converter, an acoustic output transducer, a timer, a controller and a radio receiver, the radio receiver having an idle mode of operation and a listening mode of operation, the sigma-delta modulator being adapted for generating a driving signal based on an output signal from the digital signal processor, the first quantizing block being adapted for generating a first bit stream and the second quantizing block being adapted for generating a second bit stream based on the sigma-delta modulator output signal, the first bit stream incorporating two discrete levels and the second bit stream incorporating three discrete levels, the controller being adapted for enabling the decoder to select one bit stream among the first and the second bit streams and for controlling the operating mode of the radio receiver, wherein said controller is configured to make the decoder select the first bit stream whenever the radio receiver is in the listening mode, and make the decoder select the second bit stream whenever the radio receiver is in the idle mode.
Additional features will appear from the dependent claims.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be explained in greater detail with respect to the drawings, where
FIG. 1 is a schematic of an H-bridge output stage for a hearing aid according to an embodiment of the invention,
FIG. 2 is a table showing possible states of the H-bridge output stage of the hearing aid according to an embodiment of the invention,
FIG. 3 is a flowchart of an algorithm for controlling the operating modes according to an embodiment of the invention,
FIG. 4 is a graph illustrating the operating sequence of the output stage and the radio receiver of the hearing aid according to an embodiment of the invention, and
FIG. 5 is a schematic of a hearing aid having an H-bridge output stage according to an embodiment of the invention.
DETAILED DESCRIPTION
The schematic in FIG. 1 shows an output stage 1 for use with a hearing aid according to the invention. The output stage comprises a sigma-delta modulator 2 , a first comparator 8 constituting a first quantizer, a second quantizer 13 comprising a second comparator 9 and a third comparator 10 , a decoder 11 , an H-bridge 12 , a controller 16 , a control wire 14 , a controlled switch 15 , a radio receiver 17 , an antenna 18 and an acoustic output transducer 19 . The sigma-delta modulator 2 comprises a difference node 3 , a first summing node 4 , a second summing node 5 , a first unit delay block 6 and a second unit delay block 7 . The H-bridge comprises a first transistor 20 , a second transistor 21 , a third transistor 22 , and a fourth transistor 23 . Also shown in FIG. 1 is an output terminal from a digital signal processor DSP of the hearing aid.
The output terminal of the digital signal processor DSP is connected to the input of the sigma-delta converter 2 . The output terminal of the digital signal processor DSP is connected to a first input of the difference node 3 of the sigma-delta converter 2 , and a feedback loop from the output of the sigma-delta converter 2 is connected to a second input of the difference node 3 . The output of the difference node 3 is connected to a first input of the first summing node 4 , and the output of the first unit delay block 6 is connected to a second input of the first summing node 4 . The output of the first summing node 4 is split between an input of the first unit delay block 6 and a first input of the second summing node 5 . An output of the second unit delay block 7 is connected to a second input of the second summing node 5 , and the output of the second summing node 5 is split between an input of the second unit delay block 7 , the feedback loop feeding the difference node 3 , and the positive inputs of the first comparator 8 , the second comparator 9 and the third comparator 10 , respectively.
The output of the sigma-delta modulator 2 is connected to the positive input terminals of the first comparator 8 , the second comparator 9 , and the third comparator 10 , respectively. The negative input terminal of the first comparator 8 is connected to logical LOW, the negative input terminal of the second comparator 9 is connected to the logical level X, and the negative input terminal of the third comparator 10 is connected to the logical level Y. The output of the first quantizer 8 is connected to a first input of the decoder 11 , and the outputs of the second quantizer 13 are connected to a second and a third input of the decoder 11 . Based on the output signal from the sigma-delta modulator 2 , the first quantizer 8 is capable of generating two different quantization levels and the second quantizer 13 is capable of generating three different quantization levels.
A first output of the decoder 11 is connected to the first transistor 20 of the H-bridge 12 , a second output of the decoder 11 is connected to the second transistor 21 of the H-bridge 12 , a third output of the decoder 11 is connected to the third transistor 22 of the H-bridge 12 , and a fourth output of the decoder 11 is connected to the fourth transistor 23 of the H-bridge 12 . The source terminals of the first transistor 20 and the third transistor 22 are connected to V ss . The drain terminal of the first transistor 20 and the source terminal of the second transistor 21 are connected to a first terminal of the acoustic output transducer 19 . The drain terminal of the third transistor 22 and the source terminal of the fourth transistor 23 are connected to a second terminal of the acoustic output transducer 19 , and the drain terminals of the second transistor 21 and the fourth transistor 23 are connected to V dd .
The control wire 14 of the controller 16 is connected to the control input of the controlled switch 15 and to a control input of the decoder 11 , respectively. The controlled switch 15 connects an output of the radio receiver 17 to an input of the controller 16 , disabling this connection whenever the controlled switch 15 is open. A signaling wire connects the radio receiver 17 to the controller 16 for providing data based on radio signals picked up by the antenna 18 and demodulated by the radio receiver 17 to the controller 16 .
When in use, the digital signal processor DSP provides a bit stream representing an audio signal to the input of the sigma-delta modulator 2 . The bit stream is conditioned by the sigma-delta modulator 2 in order to suit the inputs of the first comparator 8 , the second comparator 9 and the third comparator 10 , respectively. The first comparator 8 acts as a first two-level quantizer on the output signal from the sigma-delta modulator 2 , and the second comparator 9 and the third comparator 10 in combination act as a second three-level quantizer 13 on the output signal from the sigma-delta modulator 2 .
The first comparator 8 outputs a logical LOW level whenever the level of the output signal from the sigma-delta modulator 2 is below a first, predetermined limit and a logical HIGH level whenever the signal is above said first, predetermined limit. The second comparator 9 outputs a logical LOW level whenever the input signal is below the limit X and a logical HIGH level whenever the input signal is above the limit X. The third comparator 10 outputs a logical LOW level whenever the input signal is below the limit Y and a logical HIGH level whenever the input signal is above the limit Y.
Together, the second comparator 9 and the third comparator 10 may thus generate four possible levels for the decoder 11 . However, only three of these levels are utilized in the decoder 11 , as the condition where the output of the second comparator 9 is logical HIGH and the output of the third comparator 10 is logical LOW is treated equally to the condition where the output of the second comparator 9 is logical LOW and the output of the third comparator 10 is logical HIGH. The three conditions may be interpreted by the decoder 11 as e.g. the symbol “−1” for input levels resulting in both comparator outputs being logical LOW, the symbol “0” for input levels resulting in the two comparator outputs being mutually different, i.e. one comparator output is logical LOW while the other comparator output is logical HIGH, and the symbol “+1” for input levels resulting in both comparator outputs being logical HIGH. In this way, the first quantizer 8 effectively generates two discrete levels from the input signal from the sigma-delta modulator 2 , and the second quantizer 13 effectively generates three discrete levels from the input signal from the sigma-delta modulator 2 .
The decoder 11 is capable of selecting either the two-level output from the first quantizer 8 or the three-level output from the second quantizer 13 as the input signal to be decoded. The decoder 11 , together with the H-bridge 12 , is capable of driving the loudspeaker 19 in a two-level mode of operation whenever the output signal from the first quantizer 8 is selected as the input signal, and in a three-level mode of operation whenever the output signal from the second quantizer 13 is selected as the input signal.
The decision about which output to use as an input of the decoder 11 is determined by the state of the control wire 14 of the controller 16 . The control wire 14 may be in an asserted state or in an unasserted state, respectively. Whenever the control wire 14 is in the asserted state, the decoder 11 uses the output signal from the two-level output of the first quantizer 8 as its input signal. Asserting the control wire 14 also closes the switch 15 , thereby enabling the radio receiver 17 to receive radio signals via the antenna 18 . Whenever the radio receiver 17 is enabled to receive radio signals, information about the presence of a radio signal is conveyed to the controller 16 through a separate wire (not shown). Whenever the control wire 14 is in the unasserted state, the decoder 11 uses the output signal from the three-level output of the second quantizer 13 as its input signal. Unasserting the control wire 14 also opens the switch 15 , thereby disabling the radio receiver 17 from receiving radio signals.
Whenever the decoder 11 receives a “−1”-symbol for decoding, it turns on the second transistor 21 and the third transistor 22 , respectively, of the H-bridge 12 . The second transistor 21 connects the upper terminal of the acoustic output transducer 19 to the positive voltage V dd , and the third transistor 22 connects the lower terminal of the acoustic output transducer to the negative voltage V ss , and the loudspeaker membrane moves inwards.
Whenever the decoder 11 receives a “+1”-symbol for decoding, it turns on the first transistor 20 and the fourth transistor 23 , respectively, of the H-bridge 12 . The first transistor 20 connects the upper terminal of the acoustic output transducer 19 to the negative voltage V ss , and the fourth transistor 23 connects the lower terminal of the acoustic output transducer to the positive voltage V dd , and the loudspeaker membrane moves outwards.
Whenever the decoder 11 receives a “0”-symbol for decoding, it turns on the second transistor 21 and the fourth transistor 23 , respectively, of the H-bridge 12 . Both the second transistor 21 and the third transistor 22 then connect the upper terminal and the lower terminal of the acoustic output transducer 19 to the negative voltage V ss , and the loudspeaker membrane moves towards its resting position.
The controller 16 coordinates the quantization resolution of the output signal from the sigma-delta modulator 2 with the operation of the radio receiver 17 in such a way that the radio receiver 17 is disabled whenever the decoder 11 is using the three-level input for controlling the H-bridge 12 , and in such a way that the radio receiver 17 is enabled whenever the decoder 11 is using the two-level input for controlling the H-bridge 12 .
The table shown in FIG. 2 illustrates the possible states of the connecting wires of an acoustic output transducer similar to the acoustic output transducer 19 in FIG. 1 when connected to the H-bridge output stage of the hearing aid according to an embodiment of the invention. Beside the table is sketched an acoustic output transducer having connecting terminals A and B. In the configuration of a preferred embodiment of the hearing aid according to the invention, a sigma-delta converter together with a first quantizer, a second quantizer and a decoder may generate either two or three different output symbols intended for the H-bridge output stage of the hearing aid.
When the symbol “−1” is generated, the H-bridge output stage connects the terminal A of the acoustic output transducer to a negative voltage, preferably the negative battery voltage, denoted V dd , and the terminal B of the acoustic output transducer to a positive voltage, preferably the positive battery voltage, denoted V ss . This induces an electromotive force in the transducer coil of the acoustic output transducer in the direction from terminal B to terminal A, and a transducer membrane mechanically connected to the transducer coil will thus move in one direction, say, inwards.
When the symbol “+1” is generated, the H-bridge output stage connects the terminal A of the acoustic output transducer to the positive battery voltage V ss , and the terminal B of the acoustic output transducer to the negative battery voltage V dd . This induces an electromotive force in the transducer coil of the acoustic output transducer in the opposite direction, i.e. from terminal A to terminal B, and the transducer membrane will thus move in the opposite direction, say, outwards.
When the symbol “0” is generated, the H-bridge output stage connects both the terminal A and the terminal B of the acoustic output transducer to the negative battery voltage V dd . No electromotive force is induced in the transducer coil of the acoustic output transducer in this case, and the transducer membrane will thus move towards its resting position.
When the H-bridge is put into two-level mode, the symbol “0” is not generated. The switching between two-level mode and three-level mode is beneficially performed in the decoder. By changing the quantization resolution of the output signal from the sigma-delta modulator from two levels to three levels, or vice versa, in the decoder, the feedback history of the sigma-delta modulator is preserved in its entirety. As shown in FIG. 1 , this may be performed by the decoder having both the two-level and the three-level quantization resolution available at all times, and selecting the appropriate quantization resolution for driving the output for the acoustic output transducer of the hearing aid as necessary. The fact that the feedback history of the sigma-delta modulator is preserved in its entirety implies that switching between the two-level mode and the three-level mode of the sigma-delta modulator is performed seamlessly with regard to the output signal to the acoustic output transducer without any audible artifacts.
An easy way of providing both a two-level modulation and a three-level modulation of the bit stream could be to employ two separate sigma-delta modulators. If a two-level sigma-delta modulator in parallel with a three-level sigma-delta modulator were used instead of a single sigma-delta modulator having both two-level and three-level capability, the feedback history of the sigma-delta modulator would be lost every time a transition from the two-level mode to the three-level mode, or vice versa, were made. This configuration would inevitably introduce undesirable, spurious transients into the output signal. By introducing a single sigma-delta modulator capable of selectively producing both a two-level and a three-level modulation of the output bit stream, the feedback history of the output stage is preserved when switching between different quantizing resolutions.
In FIG. 3 is shown a flowchart illustrating a preferred control algorithm for a radio receiver and an H-bridge output stage of the hearing aid according to the invention. The timing values used by the algorithm in FIG. 3 are calculated and detected by an external subroutine, and are thus not shown. Only the timing flags are passed implicitly to the algorithm shown in FIG. 3 based on the timing values encountered by the system. The algorithm, initiating in step 301 , continues immediately to step 302 , where the radio receiver is put into an idle mode. The algorithm sets the H-bridge output stage in a three-level mode in step 303 and enters a loop in step 304 . In step 304 , the algorithm determines if fifty milliseconds have elapsed since the radio receiver was last put into the idle mode. If this is not the case, the algorithm loops back into step 304 until the fifty milliseconds have elapsed, and continues to step 305 , where the radio receiver is put into a listening mode. The algorithm then continues unconditionally to step 306 , where the H-bridge output stage is put into a two-level mode.
The algorithm continues in step 307 , where an indicator in the radio receiver informs the algorithm if a radio signal is present. If this is not the case, the algorithm branches out into a test, carried out in step 308 , to determine if ten milliseconds have elapsed since the radio receiver were put into the listening mode without detecting a signal. If ten milliseconds have not yet elapsed, the algorithm loops back into step 307 in order to test if a radio signal has been picked up yet by the radio receiver. Otherwise, if ten milliseconds have elapsed without the radio receiver detecting the presence of a radio signal, the algorithm loops back into step 302 , where the radio receiver is put back into the idle mode, and continues unconditionally into step 303 , where the H-bridge is put back into the three-level mode and the procedure of the algorithm is repeated indefinitely.
If, however, a radio signal is indeed detected by the radio receiver while the algorithm is processing step 307 , the algorithm instead continues into step 309 , where a subroutine (not shown) is called for carrying out the process of decoding the data bits received by the radio receiver of the hearing aid. The algorithm continues into step 310 , where a test is carried out in order to determine if one hundred milliseconds have elapsed since a signal was detected by the radio receiver. If this is not the case, the algorithm loops back into step 309 and continues the process of decoding the data bits received by the radio receiver. Otherwise, the algorithm continues into step 311 , where a test is carried out in order to determine if a radio signal is still present. If this is the case, the algorithm loops back into step 309 and continues the decoding process. If this is not the case, the algorithm instead loops back into step 302 , where the radio receiver is put back into the idle mode, and continues to step 303 , where the H-bridge is put back into the three-level mode.
The essence of the functionality of the algorithm shown in FIG. 3 is as follows: The radio receiver of the hearing aid is put into the idle mode and the H-bridge output stage of the hearing aid is put into the three-level mode for fifty milliseconds. Then the radio receiver listens for the presence of a radio signal while the H-bridge output stage is put into the two-level mode in order to minimize interference. If no signal has been detected by the radio receiver for a period of ten milliseconds, the radio receiver is put back into the idle mode and the H-bridge output stage is put back into the three-level mode in order to conserve power. However, if the radio receiver of the hearing aid detects the presence of a radio signal, reception and decoding of the received radio signal is commenced. Every 0.1 seconds a test is performed in order to determine if a radio signal is still present. If this is the case, the reception and decoding of the received radio signal continues. If a radio signal is no longer deemed to be present, the radio receiver is once again put back into the idle mode and the H-bridge output stage is put back into the three-level mode in order to conserve power.
FIG. 4 shows an exemplified set of graphs illustrating the interoperational characteristics between an output stage and a radio receiver in a hearing aid according to the invention. The upper graph in FIG. 4 illustrates the state of the control wire 14 of the controller 16 as shown in FIG. 1 , the middle graph in FIG. 4 shows the output signal of the H-bridge 12 seen across the input terminals of the acoustic output transducer 19 in FIG. 1 , and the lower graph in FIG. 4 shows the activity of the receiver 17 in FIG. 1 when controlled by the controllable switch 15 controlled by the control wire 14 of the controller 16 in FIG. 1 . All three graphs are assumed to be synchronous.
The upper graph in FIG. 4 illustrates that the control wire 14 of FIG. 1 is asserted for short periods of time, thus enabling the radio receiver 17 in FIG. 1 and forcing the H-bridge output stage to operate in the two-level mode. Whenever the control wire is unasserted, the radio receiver is disabled and the H-bridge output stage is operated in the three-level mode. This is illustrated by the middle graph in FIG. 4 , where an arbitrary output signal from the H-bridge output stage is exhibiting three-level operation when the control wire is unasserted and two-level operation when the control wire is asserted. The lower graph in FIG. 4 illustrates the operation of the receiver 17 in FIG. 1 .
The operation of the output stage of the hearing aid according to the invention, as illustrated by the graphs in FIG. 4 , will now be explained in further detail with reference to the elements shown in FIG. 1 . Below the lower graph in FIG. 4 is suggested a timeline with eight time instants, labeled from T 1 to T 8 . At the instant 0, the control wire 14 is unasserted, the radio receiver 17 is inactive, and the H-bridge output stage 1 is operating in the three-level output mode, delivering the three-level digital output signal directly to the acoustic output transducer 19 of FIG. 1 .
At the instant T 1 , the control wire 14 is asserted, and the H-bridge output stage 1 changes its operation from the three-level output mode to the two-level output mode. At the same time, the radio receiver 17 is activated. This condition persists until the instant T 2 , approximately ten milliseconds later, where the control wire 14 is unasserted, the radio receiver 17 is inactivated, and the H-bridge output stage 1 is set to change its operation back into the three-level output mode. From the instant T 2 until the instant T 3 , approximately fifty milliseconds later, the control wire 14 is unasserted, leaving the H-bridge in the three-level output mode and the radio receiver 17 inactive. In this case, a radio signal R 0 , superimposed onto the lower graph of FIG. 4 in a dotted line, incidentally occurs between the instant T 2 and the instant T 3 . Because the radio receiver 17 is in its inactive mode, the radio signal R o is not picked up by the radio receiver 17 of the hearing aid.
At the instant T 3 , the radio receiver 17 is activated again by asserting the control wire 14 , and the H-bridge output stage 1 changes its operation from the three-level output mode to the two-level output mode. Since no radio signal is detected by the radio receiver 17 between the instant T 3 and the instant T 4 , the control wire 14 is unasserted at the instant T 4 , approximately ten milliseconds later, when the radio receiver 17 is deactivated again, and the H-bridge output stage 1 has its operation changed back into the three-level output mode.
Between the instant T 4 and the instant T 5 , another radio signal R 1 , superimposed onto the lower graph of FIG. 4 in a thin, solid line, occurs, but since it is still present at T 5 , it is detected by the radio receiver 17 . The detection of the radio signal R 1 by the radio receiver 17 makes the controller 16 keep the control wire 14 asserted, thus keeping the radio receiver 17 active and the H-bridge output stage 1 operating the two-level output mode. Within the time period between the instant T 5 and the instant T 6 , a third radio signal R 2 , superimposed onto the lower graph of FIG. 4 in a thin, solid line, is detected and decoded by the radio receiver 17 . The radio receiver 17 keeps a reception flag asserted during reception of the radio signal R 2 , and thus prevents the return of the radio receiver 17 to its inactive state. This, in turn, also delays the return of the H-bridge output stage 1 to the two-level output mode.
When the radio signal R 2 ceases, a timing function delays the unassertion of the control wire 14 for a predetermined period of time. As no other radio signal is detected before the instant T 6 , the control wire 14 is unasserted again at T 6 . Hereby the radio receiver 17 is inactivated, and the H-bridge output stage 1 changes its operation back to the three-level output mode. At the instant T 7 , after approximately another fifty milliseconds, the radio receiver 17 is activated again by asserting the control wire 14 , and the H-bridge output stage 1 changes its operation from the three-level output mode to the two-level output mode. The control wire 14 is unasserted again at the instant T 8 , approximately ten milliseconds later, whereby the radio receiver 17 is deactivated again, and the H-bridge output stage 1 changes its operation back into the three-level output mode.
In order to demonstrate the operating principles of the H-bridge output stage according to an embodiment of the invention, the three bursts of radio transmission illustrated by the lower graph in FIG. 4 are shown as being rather short. This is done to illustrate, in as brief a way as possible, the fact that the radio receiver 17 is only capable of receiving radio signals when it is activated by the controller 16 of the hearing aid, and that the radio receiver 17 has the ability to delay a pending inactivation whenever a radio signal is encountered. In a practical example, radio transmissions intended for the hearing aid will be significantly longer, preferably spanning a considerably longer period of time than the sixty milliseconds shown elapsing between two activations of the radio receiver in the example.
In FIG. 5 is shown a schematic of a hearing aid 40 incorporating an H-bridge output stage according to an embodiment of the invention. The hearing aid 40 comprises an acoustic input transducer 30 , an analog-to-digital converter 31 , a digital signal processor 32 , a sigma-delta modulator 2 , a first quantizer block 8 , a second quantizer block 13 , a decoder 11 , an H-bridge 12 , a controller 16 , a control wire 14 , a controllable switch 15 , a timer 33 , an acoustic output transducer 19 , and a radio receiver 17 having an antenna 18 . In FIG. 5 is also shown a radio transmitter 34 having an antenna 35 . The sigma-delta converter 2 , the decoder 11 , the controller 16 , the H-bridge 12 , the acoustic output transducer 19 and the radio receiver 17 are considered to be similar to the corresponding parts of the system shown in FIG. 1 .
When in use, the microphone 30 of the hearing aid 40 picks up acoustic signals and converts them into electrical signals and feeds the electrical signals to an input of the analog-to-digital converter 31 . The digital output signal from the analog-to-digital converter 31 is used as the input for the digital signal processor 32 , where the main part of the signal processing, e.g. filtering, compression, prescription gain calculation etc. takes place. The output signal from the digital signal processor 32 is a digital signal, which is fed to the input of the sigma-delta modulator 2 .
The output signal from the sigma-delta modulator 2 , which may be considered to be a digital bit stream, is split into two branches, one branch going to the first quantizing block 8 , and the second branch going to the second quantizing block 13 . The output signals from the first and second quantization blocks 8 , 13 , are presented as input signals to the decoder 11 . The decoder 11 generates a set of control signals for the H-bridge 12 . The output terminals of the H-bridge 12 are connected to the input terminals of the acoustic output transducer 19 , and the H-bridge 12 generates a digital output signal for the acoustic output transducer 19 .
The output signal from the first quantization block 8 is a two-level bit stream intended for driving the H-bridge 12 in a two-level mode via the decoder 11 . The output signal from the second quantization block 13 is a three-level bit stream intended for driving the H-bridge 12 in a three-level mode via the decoder 11 . The decoder 11 is thus capable of selecting either the output signal from the first quantization block 8 or the output signal from the second quantization block 13 as the input signal for generating the set of control signals for the H-bridge 12 .
When the two-level output signal from the first quantization block 8 is used, the decoder 11 is said to be operating in a two-level mode, and when the three-level output signal from the second quantization block 13 is used, the decoder 11 is said to be operating in a three-level mode. The radio receiver 17 is capable of operating in an idle mode, wherein radio signal reception is suppressed, and in an active mode, wherein radio signal reception is enabled.
The controller 16 determines which mode the decoder 11 is supposed to be using in a given situation in order to generate the set of control signals for the H-bridge 12 . For this purpose, the controller 16 utilizes information from the timer 33 and the radio receiver 17 , respectively, to determine what the mode of operation for the decoder 11 should be. The timer 33 generates a timing sequence similar to the timing sequence shown in FIG. 4 . This timing sequence is used by the controller 16 to control the operation of the decoder 11 and the radio receiver 17 of the hearing aid 40 . During a first phase of the timing sequence, the timer 33 sends a signal to the controller 16 at regular intervals in order to make it change the operation of the radio receiver 17 from the idle mode to the active mode and force the decoder 11 to select the two-level bit stream from the first quantizer block 8 for the H-bridge 12 in order for it to operate in the two-level mode.
When the controller 16 determines that the radio receiver 17 should change its mode of operation from the idle mode to the active mode based on the signal from the timer 33 , the controller 16 asserts the control wire 14 in order to engage the controlled switch 15 for activating the radio receiver 17 . Simultaneously, the controller 16 forces the decoder 11 , via the control wire 14 , to select the two-level bit stream originating from the first quantizing block 8 for controlling the H-bridge 12 . The radio receiver 17 is now in the active mode, and the H-bridge 12 is producing a two-level bit stream for the acoustic output transducer 19 .
Unless the radio transmitter 34 transmits a radio signal which is picked up by the radio receiver 17 while it is in the active mode, the controller 16 waits for a signal from the timer 33 and unasserts the control wire 14 upon detecting the signal from the timer 33 , thus disengaging the controlled switch 15 , in turn forcing the radio receiver 17 back into the idle mode, and makes the decoder 11 select the three-level bit stream from the second quantizing block 13 for controlling the H-bridge 12 . If, however, the radio transmitter 34 transmits a radio signal, and this radio signal is detected by the radio receiver 17 , a signal is sent from the radio receiver 17 to the controller 16 , informing the controller 16 to postpone signals from the timer 33 until the radio receiver 17 informs the controller 16 that it has finished receiving and decoding the radio signal.
The timer 33 now enters a second phase in the timing sequence, wherein the controller 16 regularly checks the status of the radio receiver 17 in order to determine that the radio receiver 17 is still receiving and decoding a radio signal. If this is the case, the controller maintains status quo, i.e. it keeps the H-bridge 12 operating in the two-level mode and keeps the radio receiver 17 in the active mode. When the radio transmitter 34 ends a transmission, the radio receiver 17 stops detecting a radio signal, and thus ends the decoding process. Upon terminating the decoding process, the radio receiver 17 sends a signal to the controller 16 in order to convey the information that reception of the radio signal has ended. Upon getting this piece of information, the controller 16 then waits for a signal from the timer 33 before deactivating the radio receiver 17 and forcing the H-bridge 12 into the three-level mode, producing a three-level bit stream to the acoustic output transducer 19 .
In a preferred embodiment, the first phase of the timing sequence of the timer 33 , as described in the foregoing, is considerably shorter than the second phase. This relationship between the two phases of the timing sequence is preferred because it allows the H-bridge 12 to operate for as long as possible in the power-saving three-level mode of operation during the first phase of the timing sequence, and prevents premature reentrance of the H-bridge 12 into the three-level mode of operation while the radio receiver 17 receives and decodes a radio signal, thus reducing the risk of the reception of the radio signal being corrupted by capacitive interference from the H-bridge 12 . | In a hearing aid ( 40 ), a direct-digital H-bridge output driver stage ( 1 ) driven by a sigma-delta modulator ( 2 ) is configured to operate in a power-saving three-level output mode or a power-consuming two-level output mode. The three-level output mode of the H-bridge output driver stage ( 1 ) has low power consumption but suffers the disadvantage of emitting capacitive noise potentially interfering with the reception of radio signals in a radio receiver ( 17 ) in the hearing aid ( 40 ). By providing a novel method of selecting the two-level output mode whenever the radio receiver ( 17 ) is receiving signals, and selecting the three-level output mode whenever the radio receiver ( 17 ) is idle, this capacitive interference does not disturb the radio receiver ( 17 ) in the hearing aid ( 40 ). The invention provides a method and a hearing aid. | 51,024 |
CROSS-REFERENCED RELATED APPLICATIONS
[0001] This application is a continuation of International Patent Application No. PCT/CH2009/000042 filed Feb. 4, 2009, which claims priority to Swiss Patent Application No. 189/08 filed Feb. 11, 2008, the entire contents of each are incorporated herein by reference.
BACKGROUND
[0002] The present invention relates to devices for administering, injecting, infusing, delivering or dispensing a substance, and to methods of making and using such devices. More particularly, it relates to a device for administering a fluid or liquid product or substance, e.g. fluid medicaments, pharmaceuticals or cosmetics. More particularly, it relates to a device for administering a fluid product that is to be mixed in a two-chamber carpule (which also may be thought of and/or referred to as an ampoule, container, or the like) before use.
[0003] In the treatment of various diseases, e.g. diabetes, and in cases of impaired growth, injection devices or appliances, which may be called injections pens or simply pens, are used to inject a medicament in the form of a fluid product into the body tissue. Such pens can also be used for other pharmaceutical or cosmetic purposes. Typically, a pen comprises a housing, an administering mechanism accommodated at least partially in the housing, and a receptacle for receiving the fluid product, e.g. a carpule holder, which receives a carpule and which is supported by or attached to the housing to connect the carpule to the administering mechanism. Generally, the administering mechanism is composed of a mechanism that is able to drive or move a stopper in the carpule. Generally, at the end of the carpule holder and directed away from the mechanism, an injection needle unit is fitted which forms a fluid connection to the fluid product in the carpule. Typically, an injection pen comprises a trigger button, the actuation of which activates the administering mechanism, such that the medicament is ejected from the carpule through the injection needle. In the prior art, it is known to block or lock the trigger button or to cover it, or in some other way to safeguard against accidental triggering. The blocking or safety feature is overridden or released just before use of the injection pen to be able to carry out an injection.
[0004] Two-chamber carpules are often used in practice, these being provided, for example, for administration of hormone preparations. The two-chamber carpules have a first chamber with a lyophilized active substance, and a second chamber with a solvent. The active substance is dissolved in the solvent just before administration, by the solvent being conveyed into the chamber containing the active substance. These two-chamber carpules have two stoppers, which separate the two chambers from each other. During the mixing of the active substance, the two stoppers are moved inside the carpule in such a way that the solvent can run through a bypass into the chamber containing the active substance. Especially when using two-chamber carpules of this kind in an injection pen, it is important to ensure that no accidental or premature administration is initiated, since in such cases the medicament may not have been completely mixed.
SUMMARY
[0005] It is an object of the present invention to make available an administering device which minimizes or avoids the chance of accidental or premature actuation of the device and thus increases the safety of the device.
[0006] In one embodiment, the present invention comprises an apparatus for administering a substance, comprising a housing, an administering mechanism accommodated in the housing, an actuation element for actuating the administering mechanism, a receptacle for holding the substance, and a lock for releasably locking the actuation element, wherein the receptacle is rotatable relative to the housing and the lock can be unlocked by rotating the receptacle.
[0007] In one embodiment, the present invention comprises a device for administering a fluid product comprising a housing for receiving an administering mechanism, an actuation element for actuating the administering mechanism, a receptacle for receiving the fluid product, and a blocking mechanism (which also may be thought of and/or referred to as a lock) for blocking the actuation element. The housing of the device can have a sleeve-shaped configuration, such that the device has the shape of a pen or pencil. An aspect of the configuration of the housing is that the administering mechanism can be accommodated therein without its function being impaired. It is also possible for the housing to carry and/or include functional elements of the administering mechanism and, thus, form part of the administering mechanism.
[0008] In some embodiments, for example, the administering mechanism is composed of a mechanism generally comprising an advancing member, e.g. a piston rod, which can be advanced relative to the housing in the direction of the receptacle for the fluid product. There, it generally contacts a stopper in the receptacle, such that the movement of the advancing member also has the effect that the stopper in the receptacle is driven forward and the fluid product is discharged. The advancing member can be driven manually. However, it is also possible to provide a drive in the form of a pretensioned spring. Moreover, non-mechanical drives may be used, e.g. pneumatic drives.
[0009] The actuation element for actuating the administering mechanism is movable relative to the housing, to be able to act on the administering mechanism. The actuation element can protrude from the housing in the form of a button. However, it is also possible to arrange the actuation element laterally on the housing, e.g. in the form of a slide or lever. The actuation element can be used to activate the administering mechanism, e.g. the advancing member, directly, or a pretensioned spring element can be released from its pretensioning and then act in turn on the advancing member.
[0010] The fluid product is accommodated in the receptacle for receiving the fluid product. In some preferred embodiments, the fluid product is located or contained in a carpule or the like that can be inserted into the receptacle. Such carpules generally have a first end, closed off by a stopper, and a second end, closed off by a thin membrane through which a needle of an injection needle unit can be pushed for and/or during use. The receptacle with the carpule can be attached to the administering mechanism by inserting the receptacle into the housing or mounting it on the housing.
[0011] To block or lock the actuation element, a device for administering a fluid product in accordance with the present invention has a blocking mechanism (which also may be thought of and/or referred to as a lock). The blocking mechanism prevents the actuation of the actuation element and, consequently, the actuation of the administering mechanism when the blocking mechanism is locked or located in a blocking position. The blocking mechanism can be moved from the blocking position to a release (released or unlocked) position in which the actuation element can be actuated to administer the fluid product by the administering mechanism.
[0012] According to the present invention, the receptacle is mounted so as to be rotatable relative to the housing, the blocking mechanism being movable from the blocking position to the release position by rotation of the receptacle relative to the housing. The receptacle is in this case rotated, for example, about a longitudinal axis of the housing or of the receptacle. Thus, by the rotation of the receptacle, an injection pen in accordance with the present invention can be unlocked and the administering mechanism triggered using the actuation element.
[0013] Locking and unlocking of the blocking mechanism in accordance with the present invention is advantageous when using two-chamber carpules which, for the mixing procedure, are turned or screwed into the housing of the administering device. In this case it is possible, by the rotation, to trigger the mixing procedure in the two-chamber carpule and also to move the blocking mechanism to the release or unlocked position. It is also possible for the receptacle to be arranged on or in the housing by a bayonet coupling, which bayonet coupling is also established by a rotation movement. In this rotation too, according to the present invention, the blocking mechanism can at the same time be moved to a release position.
[0014] In some preferred embodiments, to move the blocking mechanism from the blocking position to the release position, the receptacle has an abutment and the blocking mechanism has a counter-abutment. The abutment of the receptacle and the counter-abutment of the blocking mechanism interact in such a way that, upon rotation of the receptacle relative to the housing, they contact each other and, upon further rotation of the receptacle, they entrain the blocking mechanism and move the latter from the blocking position to the release position. For this purpose, the blocking mechanism is rotatable, for example, relative to the housing in the circumferential direction of the housing.
[0015] As soon as the blocking mechanism is located in the released or unlocked position, the actuation element can be activated. In some preferred embodiments, in the release position of the blocking mechanism, the actuation element may be moved relative to the housing along the longitudinal axis of the housing. For example, an actuation button protruding from the housing at one end is pressed or pushed into the housing.
[0016] According to one embodiment of the present invention, the blocking mechanism is arranged on the actuation element. For example, the blocking mechanism and the actuation element can be structured as one piece. In this case, the blocking mechanism and the actuation element can be produced from a single section. However, it is also possible to subsequently secure the blocking mechanism on the actuation element. In one variant, the actuation element then moves along with the blocking mechanism when the blocking mechanism is moved from the blocking position to the release position. For example, the actuation element is rotated along with the rotation of the receptacle.
[0017] In another variant, the blocking mechanism may be a flexible arm. The flexible arm can deflect in the circumferential direction of an axis of the actuation element, that is to say it can bend away from its rest position in a direction of rotation about the longitudinal axis. In this embodiment, the flexible arm forms the counter-abutment of the blocking mechanism, which counter-abutment interacts with the abutment of the receptacle. As the receptacle rotates, its abutment contacts the flexible arm and deflects the arm from the rest position, as a result of which the blocking mechanism is moved to a release position.
[0018] In some preferred embodiments, the blocking or locking of the actuation element is effected by a blocking abutment on the blocking mechanism, which blocking abutment, in the blocking position, contacts a longitudinal abutment on the housing or a structure fixed to the housing in the longitudinal direction. A longitudinal abutment is to be understood as an abutment that blocks a movement along a longitudinal axis of the administering device. When the blocking abutment bears on the longitudinal abutment, the actuation element cannot be actuated in this longitudinal direction. The actuation element is therefore blocked against being pressed or pushed into the housing. This blocking is canceled by the deflection of the flexible arm, since the blocking abutment on the blocking mechanism is moved laterally away from the longitudinal abutment by the deflection of the flexible arm upon rotation of the receptacle. In the deflected position of the flexible arm, the blocking mechanism assumes a release or unlocked position. The blocking abutment can then be guided laterally past the longitudinal abutment in the longitudinal direction when the actuation element is moved into the housing.
[0019] In another embodiment of the present invention, the blocking mechanism is designed as a rotary element that can be rotated relative to the actuation element. In this case, the blocking mechanism has a blocking abutment which, in the blocking position, contacts a longitudinal abutment on the actuation element, on the housing, or a part fixed to the housing. In this embodiment, the actuation element is therefore not movable in the longitudinal direction of the housing relative to the blocking mechanism in the blocking position. If the longitudinal abutment is provided on the actuation element, the rotary element is mounted rotatably in the housing such that it is not movable relative to the housing in the longitudinal direction. By rotating the rotary element by the rotation of the receptacle, the blocking abutment is removed from the longitudinal abutment on the actuation element, and the blocking is canceled. The actuation element can then be moved in the longitudinal direction relative to the housing and to the rotary element.
[0020] If the longitudinal abutment is provided on the housing or on a part fixed to the housing, the rotary element is mounted rotatably in the housing such that, in the blocking position, it is rotatable relative to the housing but not longitudinally movable and, in the release position, can be moved in the longitudinal direction relative to the housing. The blocking thus acts between the blocking mechanism, in the form of the rotary element, and the housing. If the rotary element is rotated relative to the housing by the rotation of the receptacle, the blocking abutment is moved away from the longitudinal abutment on the housing or on the part fixed to the housing. The blocking mechanism can then be moved, together with the actuation element, relative to the housing in the longitudinal direction. Thus, in these variants too, the actuation element is prevented from being activated. The blocking mechanism and the rotary element are rotated by the rotation movement of the receptacle relative to the housing, by the abutment on the receptacle and the counter-abutment on the blocking mechanism. By this rotation, the abutment action between the blocking abutment of the blocking mechanism and the longitudinal abutment on the actuation element or on the housing or on the part fixed to the housing is canceled, and these abutments can be moved past one another in the longitudinal direction. Accordingly, in this position, the blocking mechanism is located in a release position in which the actuation element can be activated.
[0021] In some embodiments, it may be advantageous if the rotary element of the blocking mechanism is secured in the blocking position. Such securing can, for example, be afforded by a press fit or by a pretensioning of a spring element. Upon rotation of the receptacle, the rotary element is then pushed out of the press fit or deflected counter to the spring tension.
[0022] In some embodiments of the present invention, it is advantageous to provide a catch mechanism which locks the receptacle relative to the housing in the release position of the blocking mechanism. The locking action ensures that the receptacle does not rotate back in the opposite direction and cause the blocking mechanism to move from the release position back to a blocking position. Such a catch mechanism can, for example, be in the form of a snap-action or detent mechanism on the receptacle, which snaps into a recess on the housing.
[0023] The present invention is advantageous when using a two-chamber carpule in a device for administering a fluid product. The receptacle for the two-chamber carpule has a thread, and the housing has a matching thread. Thus, the receptacle can be turned or screwed into the housing. When using the two-chamber carpule, the screwing of the receptacle into the housing can be used to mix the components or constituents of the fluid product in the two-chamber carpule. By screwing the receptacle into the housing, a first stopper in the two-chamber carpule is pushed forward (i.e., distally), e.g. by the advancing member of the administering mechanism. The forward movement is transferred via the solvent in the first chamber to the second stopper which separates the solvent chamber from the active substance chamber. The two stoppers are moved uniformly until the second stopper has arrived at a bypass in the carpule wall, through which bypass the solvent can run from the solvent chamber into the active substance chamber. The first stopper is pushed forward until the solvent is in the first chamber, and until the first stopper comes to lie on the second stopper. The screwing-in of the two-chamber carpule is such that the blocking mechanism is moved from the blocking position to the release position as soon as all of the solvent has passed from the solvent chamber to the active substance chamber. By the catch mechanism, the receptacle is locked relative to the housing in the release position of the blocking mechanism, such that the administering device, in this position, is ready for an injection, that is to say the active substance has been mixed completely and the blocking of the administering device is canceled. As soon as an injection needle unit is fitted onto the receptacle, an injection can be performed. In this embodiment, it is advantageous that no separate maneuver is needed to unlock the blocking mechanism, and instead the blocking action is canceled by the necessary mixing of the two-chamber carpule.
BRIEF DESCRIPTION OF THE DRAWINGS
[0024] FIG. 1 depicts an embodiment of an administering device in accordance with the present invention in a starting state,
[0025] FIG. 2 shows the administering device in a state when mixing has taken place,
[0026] FIG. 3 shows the administering device in a state when air has been removed,
[0027] FIG. 4 shows the administering device in a triggered state,
[0028] FIG. 5 shows the administering device in a state after a product has been discharged,
[0029] FIG. 6 a is an inside view of the administering device in a blocking position,
[0030] FIG. 6 b is an inside view of the administering device in a release position,
[0031] FIG. 7 a is a detailed view of another embodiment of an administering device in a blocking position, and
[0032] FIG. 7 b is a detailed view of the administering device of FIG. 7 a in a release or unlocked position.
DETAILED DESCRIPTION
[0033] With regard to fastening, mounting, attaching or connecting components of the present invention, unless specifically described as otherwise, conventional mechanical fasteners and methods may be used. Other appropriate fastening or attachment methods include adhesives, welding and soldering, the latter particularly with regard to the electrical system of the invention, if any. In embodiments with electrical features or components, suitable electrical components and circuitry, wires, wireless components, chips, boards, microprocessors, inputs, outputs, displays, control components, etc. may be used. Generally, unless otherwise indicated, the materials for making embodiments of the invention and/or components thereof may be selected from appropriate materials such as metal, metallic alloys, ceramics, plastics, etc. Unless otherwise indicated specifically or by context, positional terms (e.g., up, down, front, rear, distal, proximal, etc.) are descriptive not limiting. Same reference numbers are used to denote same parts or components.
[0034] FIGS. 1 to 6 show an embodiment of an administering device according to the present invention with a blocking mechanism, or lock, for blocking an actuation element. FIGS. 7 a and 7 b show another embodiment of a blocking mechanism for blocking an actuation element. Each of FIGS. 1 to 5 shows two views, of which the second view at the bottom is turned through 90° in relation to the first view at the top.
[0035] The administering device according to one embodiment of the present invention uses a two-chamber carpule as container for a fluid product. The fluid product is discharged from the carpule by a drive member being moved forward (distally) by a discharging spring. The product is therefore discharged automatically as soon as the discharging spring is activated. The administering device has a fixed dose, i.e. the discharge volume is fixed. The forward movement of the drive member is therefore also fixed and cannot be individually adjusted. The administering device is blocked or locked after a single discharge procedure and is discarded after the discharge procedure.
[0036] It should be clear to a person skilled in the art that a blocking mechanism or lock according to the present invention can be used equally advantageously in reusable administering devices, in devices with individual dosing or manual discharge, and also in devices with single-chamber carpules.
[0037] In the text below, the term distal (and terms front or forward) refer to the end of the administering device at which the fluid product is discharged, and the term proximal designates the opposite end (the rear or back end).
[0038] The administering device according to one embodiment of the present invention has a housing 1 , a receptacle for receiving the fluid product or substance to be administered in the form of a carpule holder 2 , a drive member 3 with a holding mechanism in the form of holding arms 4 , a blocking mechanism in the form of a blocking ring 5 , and an actuation element in the form of a trigger button 6 .
[0039] A two-chamber carpule 7 is accommodated in the carpule holder 2 . The two-chamber carpule has a first stopper 8 a and a second stopper 8 b . The second stopper 8 b closes the two-chamber carpule at the proximal end. At the distal end, the two-chamber carpule has a narrowed area whose opening is closed off by a membrane. The membrane can be pierced by a needle of an injection needle unit. The injection needle unit is not shown in the figures. A first chamber 9 a , in which a dry or lyophilized active substance is accommodated (not shown), is formed between the membrane and the first stopper 8 a . A second chamber, in which the solvent for the active substance is stored, is formed between the first stopper 8 a and the second stopper 8 b.
[0040] The drive member 3 has a sleeve-shaped configuration. A drive spring 10 , arranged in the inside of the drive member 3 , is clamped between a distal abutment at the sleeve base of the drive member and a proximal abutment on an element 11 fixed to the housing. In the starting state in FIG. 1 , the drive member 3 is held relative to the housing element 11 by snap-action arms 12 , which releasably snap in behind an abutment of the housing element 11 . At the distal end of the drive member 3 , the holding arms 4 are mounted in such a way that they protrude or extend laterally from a longitudinal axis of the drive member in this starting position. In the embodiment depicted, two holding arms are shown spread apart from each other. It is of course also possible to provide three or more such holding arms 4 . In the starting state in FIG. 1 , the distal ends of the holding arms 4 abut against a proximal edge of the carpule 7 . The holding arms 4 press the carpule 7 against a shoulder 13 of the carpule holder 2 . The carpule 7 is therefore held in a defined (or certain or selected) position, relative to the carpule holder 2 , by the holding mechanism in the from of the holding arms 4 . This prevents the carpule from moving back and forth in the proximal and distal directions in the holder.
[0041] In the starting state in FIG. 1 , the blocking ring 5 is located in a blocking position in which it blocks or prevents an actuation of the trigger button 6 , i.e. the trigger button 6 cannot be pressed in the longitudinal direction into the housing 1 . For this purpose, the blocking ring 5 has a blocking abutment 14 , which rests on a counter-abutment 15 on the trigger button 6 . By the blocking abutment 14 of the blocking ring 5 and the counter-abutment 15 of the trigger button 6 abutting or contacting each other, the trigger button 6 cannot be actuated, that is to say it cannot be pressed into the housing along the longitudinal axis of the housing. For this purpose, the blocking ring 5 is mounted fixedly relative to the housing in the longitudinal direction but can be rotated relative to the housing. The blocking abutment 14 can be formed, for example, by ribs or cams on the blocking ring or by the proximal edge of the blocking ring 5 .
[0042] The blocking ring 15 has a sleeve-shaped configuration and surrounds the snap-action arms 12 of the drive member 3 . In the starting state in FIG. 1 , the inner circumferential surface of the blocking ring 5 bears on the outside of the snap-action arms 12 such that the arms cannot be released from their snap-in engagement behind the housing element 11 . The blocking ring 5 thus blocks an actuation of the trigger button 6 and also a release of the snap-action arms 12 . The starting state corresponds to a delivery or purchase state in which the administering device is supplied to a user. An actuation of the administering device is not possible in this state.
[0043] FIG. 2 shows the administering device in a state when mixing has taken place, in which state the active substance of the chamber 9 a of the two-chamber carpule 7 has been mixed with the solvent of the chamber 9 b . The completion of the mixing procedure can be indicated by a tactile, acoustic or visual signal. As is shown in FIG. 2 , mixing was achieved by moving the stoppers 8 a and 8 b inside the carpule 7 until the stopper 8 a comes to lie on a bypass 16 through which the solvent can flow into the chamber 9 a and the stopper 8 b comes to lie on the stopper 8 a . For advancing the stoppers, the carpule holder 2 is screwed into the housing 1 such that the drive member, which in this state is at rest relative to the housing, moves the stoppers 8 a and 8 b relative to the carpule 7 . To screw the carpule holder in, an inner thread is provided on the inside of the housing and an outer thread is provided on the outside of the carpule holder.
[0044] As can be seen in FIG. 2 , the holding arms 4 have slipped from the proximal edge of the carpule 7 and have been moved radially inwardly in the direction of the longitudinal axis of the drive member. For this purpose, the ends of the holding arms 4 have oblique surfaces along which the holding arms 4 are deflected inwardly as soon as the proximal edge of the carpule 7 is pressed with sufficient force against the oblique surfaces, as is the case when the carpule holder 2 is screwed into the housing 1 . The holding arms 4 move in toward each other and form a ram for the stopper 8 b of the carpule 7 . By the holding arms 4 abutting against the stopper 8 b , the carpule 7 is further held in its defined position in the carpule holder 2 , while the stoppers 8 a and 8 b are moved inside the carpule 7 . Independently of this, the holding arms 4 form a press fit with the inside wall of the carpule 7 , as they have radially outward pretensioning since having being bent radially inwardly. This press fit serves to hold the carpule in a defined or set position in the carpule holder.
[0045] After the mixing has taken place in the two-chamber carpule, it may be necessary for the chamber 9 a , with the dissolved active substance, to have air removed from it before the active substance can be injected. For this purpose, an injection needle unit is mounted on the distal end of the carpule holder 2 , such that a needle pierces the membrane of the carpule 7 and thus creates a fluid connection to the chamber 9 a . Screwing in the carpule holder 2 slightly further leads to a further advance movement of the stoppers 8 a and 8 b , such that air located in the chamber 9 a can escape. The advance movement is normally carried out until a small amount of the active substance 9 a emerges from the needle of the injection needle unit. The completion of the air removal procedure, which also may be thought of and/or referred to as priming or a priming procedure, can be indicated by a tactile, acoustic or visual signal.
[0046] The state with the air removed in shown in FIG. 3 . The injection needle unit is not shown. In the last screwing-in movement of the carpule holder 2 into the housing 1 , in which air can also be removed from the carpule, the blocking ring 5 is moved from the blocking position to the release position. As is shown in FIGS. 6 a - 6 d , the carpule holder for this purpose has an abutment 17 , and the blocking ring has a counter-abutment 18 . The abutment 17 of the carpule holder 2 is designed such that it abuts in the circumferential direction against the counter-abutment 18 of the blocking ring 5 during the rotation movement of the carpule holder. Upon further rotation of the carpule holder 2 , the carpule holder carries the blocking ring 5 along with it, such that the blocking ring 5 is rotated relative to the housing 1 and to the trigger button 6 . By this rotation movement, the blocking ring is moved from the blocking position to the release position. As is shown in FIG. 3 , during the rotation the blocking abutment 14 of the blocking ring 5 is rotated away from the counter-abutment 15 of the trigger button 6 until the counter-abutment 15 lies opposite a groove or channel 19 of the blocking ring, inside which groove or channel 19 the counter-abutment 15 of the trigger button 6 can be moved in the longitudinal direction.
[0047] During the rotation of the blocking ring 5 by the carpule holder 2 , the inner surfaces of the blocking ring 5 , which prevent the snap-action arms 12 from disengaging from their snap-in position, are also rotated away from this position. In the release position of the blocking ring 5 , the snap-action arms 12 lie opposite recesses in the sleeve face of the blocking ring 5 . The blocking ring 5 is therefore also located in a release position with respect to the snap-action arms 12 .
[0048] FIG. 4 shows the administering device in a triggered state in which the trigger button 6 has been pressed into the housing 1 generally along the longitudinal axis of the housing 1 . The counter-abutments 15 of the trigger button 6 have been moved inside the channels 19 of the blocking ring 5 . The trigger button 6 has inwardly extending webs 20 which, when the trigger button is in the triggered or pushed-in state, bear against oblique surfaces on the proximal end of the snap-action arms 12 and spread the arms 12 radially outwardly as the trigger button 6 moves forward, such that the ends of the snap-action arms come to lie inside the recesses in the blocking ring 5 . The securing of the drive member 3 on the housing element 11 is canceled by the spreading-open of the snap-action arms 12 . In the triggered state, the spring force of the drive spring 10 begins to act and presses against the drive member 3 .
[0049] As is shown in FIG. 5 , the drive member 3 is moved forward relative to the carpule 7 by the force of the spring 10 and drives the stoppers 8 a and 8 b inside the carpule 7 , such that the active substance is discharged from the chamber 9 a . The drive spring 10 pushes the drive member 3 forward into the carpule until a projection 21 , provided on the drive member 3 , abuts against an edge of the housing element 11 . As soon as the projection 21 abuts against the housing element 11 , the discharging of the active substance is ended.
[0050] In the illustrative embodiment shown, a flexible arm 22 , provided on the drive member 3 , protrudes into and/or lodges in a recess in the carpule holder, when the discharging has ended, and serves to block or prevent a movement of the drive member 3 in the proximal direction. Moreover, when it catches in the recess of the carpule holder, the arm 22 produces an acoustic noise, which indicates that the discharging has been completed.
[0051] FIGS. 7 a and 7 b show another embodiment of an administering device with a blocking mechanism according to the present invention. In this variant, the blocking mechanism is arranged on the actuation element, which is in the form of the trigger button. As is shown in FIG. 7 a , a locking arm 23 protrudes or extends from the trigger button 6 in the longitudinal direction of the administering device. The locking arm 23 and the trigger button 6 are one piece or integrally connected. A blocking abutment 24 , which abuts in the longitudinal direction against a longitudinal abutment of the housing element 11 , is provided on the locking arm 23 . Because of the contact of the blocking abutment 24 with the longitudinal abutment 25 , the trigger button 6 cannot be pressed in the longitudinal direction into the housing 1 .
[0052] In FIG. 7 b , the carpule holder 2 has already been screwed into the housing 1 . The carpule holder 2 is screwed into the housing until an abutment 17 ′ of the carpule holder abuts in the circumferential direction against a counter-abutment 18 ′ of the locking arm 23 of the trigger button 6 . Upon further rotation of the carpule holder 2 , the locking arm 23 is deflected in the circumferential direction relative to its rest position, since the abutment 17 ′ acts against the counter-abutment 18 ′. The blocking abutment of the trigger button 6 is in this way deflected from its blocking position relative to the longitudinal abutment 25 of the housing element 11 and comes to lie opposite a recess in the housing element 11 . The blocking mechanism for blocking the trigger button 6 is now located in a release position in which the trigger button 6 can be pressed into the housing 1 along the longitudinal axis. The blocking abutment 24 is guided through the recess in the housing element 11 .
[0053] In this embodiment, the carpule holder 2 has a catch mechanism with which it locks relative to the housing as soon as the blocking mechanism is in a release position, such that a reverse rotation of the carpule holder and consequently a renewed blocking of the trigger button are prevented.
[0054] Embodiments of the present invention, including preferred embodiments, have been presented for the purpose of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms and steps disclosed. The embodiments were chosen and described to illustrate the principles of the invention and the practical application thereof, and to enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth they are fairly, legally, and equitably entitled. | An apparatus for administering a fluid product, including a housing, an administering mechanism accommodated in the housing, an actuation element for actuating the administering mechanism, a receptacle for holding the fluid product, and a lock for releasably locking the actuation element, wherein the receptacle is rotatable relative to the housing and the lock can be moved from a locked position to an unlocked position by rotating the receptacle. | 36,321 |
This application claims the benefit of U.S. Provisional Application No. 61/062,219, filed Jan. 24, 2008, which is hereby incorporated by reference in its entirety.
SUMMARY OF THE INVENTION
The invention provides apparatus to control the movement of heat and moisture and control temperature and humidity, by evaporation and air cooling with air flow between an armor shell, apparel, or helmet covering human or animal body using; air flow channels, water wicking material covered heat pipes, or thermal conductors in contact with human or animal body and humidity and/or temperature reactive auto-actuated laminate impedance structures or humidity and/or temperature reactive auto-actuated laminate valves.
The invention provides apparatus to control the movement of heat and chemicals and thereby control temperature and humidity, by evaporation and air cooling with fluid flow between a cover over a living body using fluid flow channels, liquid wicking material covered thermal conduits in contact with living body, and chemical concentration and/or temperature reactive auto-actuated laminate structures with varying impedance to the movement of heat and chemicals.
The invention provides apparatus to control heat and moisture flux to control temperature and humidity environment, by evaporation and air cooling with airflow between an armor shell, apparel, or helmet covering a living body using; air flow channels, water wicking material covered thermal conduits in contact with body, and humidity and/or temperature reactive auto-actuated laminate impedance structures which therein vary impedance to the flux of heat, moisture and/or fluid flow.
Elements:
remove heat and chemicals, or moisture control temperature and humidity, evaporation and air cooling with air flow between an armor shell, apparel, or helmet covering air flow channels chemical concentration and/or temperature reactive auto-actuated laminate structures which control heat and air flow wicking material covered heat thermal conduits, heat pipes, or conductor which is also in contact with the human, animal, or living body.
The use of body armor, helmets, fire proof suits, hazardous environment suits, cock pit shells, thick garments, shoes, and gloves on people such as motor cross racing drivers, racing car drivers, soldiers, police, and firefighters can lead to excessive temperatures on the wearers body. The human body reaction to maintain constant temperature is to sweat and cool by evaporation on the skin. Due to the confined conditions and lack of air circulation under the armor the sweating does not result in evaporation and effective cooling of the wearer. Thus sweat builds up under the armor and the wearer becomes uncomfortable, this can result in dehydration, in some situations even possibly lead to hyperthermia or hypothermia. In addition the moist and warm conditions on the skin are ideal growth conditions for bacterial growth and can lead to skin and wound infections of the wearers. Body oils from the wearer can also interfere with efficient wicking of sweat. In cold weather environments excessive cooling through body armor can also lead to an opposite situation of chilling the wearer of the armor.
The disclosed invention is to provide a means of wicking sweat off the body and skin onto a wicking surface covering the padding or of the of the body armor, and creating air flow passages in the padding of the helmet or body armor to allow for effective cooling by evaporation of the sweat from the wearer. Padding contact and confinement of the body armor interferes with the normal evaporative cooling of sweating and evaporation to air flow. By placing thermally conductive materials, or heat pipes inside the padding to transfer heat on contact with the body and with the evaporating sweat areas onto the wicking surfaces it restores the cooling effect of sweating. To provide optimum heat removal control to maintain desirable temperatures and humidity surrounding the wearer, humidity or temperature bi-material laminate actuating valves open to let air flow when temperatures or humidity are high to maximize air flow and evaporation and close when the temperatures are low or humidity is low to retain heat and maintain a comfortable environment about the wearer. The laminate actuators can be distributed through out the air vent channels under the body armor to achieve local control thereby uniformly maintaining desirable environmental conditions through out the apparel. Laminate actuators in the form of exterior layers or fabric can be used to cover the exterior of the body armor or helmet to act as self adjusting variable thermal insulation and ventilation to the body armor and thermally conductive elements. To insure the cooling effect of flowing air in high humidity environments water absorbent and heat dissipation an air intake filter be used to de-humidify the air flow entering the system. The air intake filter can also be an insect, dust and/or bacterial filter to keep the air flow space inside the armor clean. An air fan can be used to pump air through the system when the system is stationary or high power cooling performance is needed or the air flow resistance into passages will not allow sufficient evaporative cooling to be effective. The padding and wicking surfaces can be treated with antibacterial coating to prevent fungal and bacterial growth. Water can be distributed to the evaporating areas with tubes or membranes onto of the thermal conductors or heat pipes for additional cooling. This patent application incorporates laminated actuators of our filed patent application U.S. Ser. No. 11/702,821, filed Feb. 6, 2007, based on U.S. Provisional Application 60/765,607, filed Feb. 6, 2006 “Laminate Actuators and Valves” as if fully set forth herein as an air and heat flow control mechanism because of their simplicity, unique low mass and structural formability to be incorporated into apparel.
PRIOR ART
Hockaday Robert, et al. U.S. Pat. No. 6,772,448 B1 “Non-Fogging Goggles” Our patent describes using heat pipes to move body heat to heat the lens of a goggle. This patent describes using a water absorbent on the vents. It does describe using wicking sweat from the body contact but it does not describe using the evaporative cooling on the exterior of the heat pipe to cool the body or using actuated vents to regulate the flow air to achieve regulated body cooling.
Pierce Brendan U.S. Pat. No. 7,207,071 “Ventilated helmet system” This is an example of ribbed passageways for air flow in a helmet. This patent describes placing a dust air filter in the incoming air flow. Porous hydrophilic foam in contact with the wearer is described. Wicking with a cloth liner is described. Using the venturi effect and convective effect to draw air is described. He describes a need for metering the air flow, but does not show a method of doing this besides the passive air flow effects.
Golde Paul U.S. Pat. No. 7,017,191“Ventilated protective garment” is an example of a ventilated garment using air flow passageways and aerodynamic ventilation of the garment. Uses an air permeable panel and a ventilation slit that can be opened and closed. This patent does describe the need to able to change the ventilation and cooling with changing environment around motorcycle riders wearing helmets and leather riding suits. This patent does not describe auto actuation on humidity or temperature of the open and closing of the ventilation slit.
VanDerWoude Brian et al. US Patent application 20070028372“Medical/surgical personal protection system providing ventilation, illumination and communication” is an example of a helmet for medical personal ventilation with a sterile barrier around medical personnel. It uses a ventilation fan. This patent does not describe auto actuation on humidity or temperature control of the ventilation system, but does provide fan flow volume control with electronic control button controls.
Arnold Anthony Peter US Patent 20050193742 “Personal heat control device and method” is a personal cooling of protective head gear. They use heat pipes in the foam pads. Thermoelectric on garments is the primary claim. This patent application does not use air flow for cooling or describe evaporative cooling coupled with the heat pipes.
Barbut Denise et al. US patent applications 20070123813 and 20060276552 “Methods and devices for non-invasive cerebral cooling and systemic cooling” Describes heat pipes that are used to cerebral cooling with heat pipes inserted into the nasal cavity. They also describe using a pump to move evaporating cooling fluids into the lumens cavities inside the body. This patent application does not describe using auto actuation with humidity or temperature to control the cooling.
Simon-Toy Moshe et al. US patent application 20010003907 “Personal Cooling Apparatus and Method” Uses thermal conductors, such as graphite fibers, in contact with living body, uses wicking of sweat, antimicrobial coatings, and incorporates automatic integrated thermostat control of air flow device. It does mention a variety of air flow mechanisms fans, and convective air flow. This patent application does not use auto actuation bi-material laminate actuator valves or heat pipes.
Angus June, et al. US patent application 20020134809 “Waist Pouch” Uses moisture heat and air flow channels, wicking to evaporative cooling remote from the site of the sweating. This patent application does not use heat pipes, or auto actuation laminate actuated valves to control air flow.
Gupta Ramesh, et al. US patent application 20070204974 “Heat pipe with controlled fluid charge” is a heat pipe system that uses a controlled amount of mass working fluid to control the upper temperature limit on heat pipes heat transfer at high temperatures. This patent application does not integrate the heat pipe into apparel or animal contact.
Turner David, et al. US Patent application 20030045918 “Apparel Ventilation System” David Turner uses pressurized air flow in channels in helmets and apparel to achieve cooling. This patent application used a pressurized bladder and a plurality of air flow channels and openings in wearer contact in apparel for ventilation. Providing sufficient air ventilation for wearer's body to regulate their temperature. This patent application does describe using the perspiration of the user combined with air flow as a body's natural cooling mechanism. It also describes wicking perspiration away. This patent application describes using compressed warm or cool air as the air flow source. This patent application does not describe an auto thermal or humidity actuated air flow control system.
McCarter Walter K., et al. US Patent application 20050246826 “Cooling Garment for Use with a Bullet Proof Vest” This patent application teaches using air ribbed air flow channels under armor. Excessive sweating of wearer can lead to discomfort, skin irritation and dehydration. This device uses a detachable fan to move air flow. This patent application describes using water resistant surface coatings. This patent application does not describe an auto thermal or humidity actuated air flow control system.
Touzov; Igor Victorovich US patent application 20070151121 “Stretchable and transformable planar heat pipe for apparel and footwear, and production method thereof” This patent describes a stretchable heat pipe made of polymers and rubbers used inside shoes and apparel. It uses the effect of boiling point set by the atmospheric pressure surrounding the heat pipe, thereby reducing the transfer of heat when the body contact is bellow the boiling point of the heat pipe. This invention describes using the heat pipe in conjunction with socks and the heat pipe extending out of the apparel into the atmosphere. This heat pipe system does not describe using the wicking covering on the heat pipe and evaporative cooling on the heat pipe outer surfaces or using humidity or thermal or humidity auto actuated valve to control air flow or cooling of the heat pipe.
Clodic Denis WO/1997/006396 PCT/FR96/01270 “Footwear or clothing article with integral thermal regulation element” This patent describes a heat pipe that moves heat from relatively warm regions of the body to cooler regions of the body and the exterior atmosphere. It does describe an air circulating channel supplies forces air flow underneath the heat pipe. This patent application does not describe using auto thermal or humidity actuated air flow control system.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 Cross Sectional View of Heat Removal System for Helmet
1 . Air into helmet channels 2 . Helmet 3 . Air flow channels in the padding and heat pipe 4 . Heat pipe with fluid 5 . Layer that expands with humidity 6 . Substrate layer of the actuator that can bend 7 . Condensation and heat delivery area of the heat pipe 8 . Air flow over the exterior of the heat pipe and helmet 9 . Laminate actuator 10 . Air flow exiting the helmet 11 . Laminate actuator 12 . Heat pipe and wick out of the rim of the helmet 13 . Head of the wearer 14 . Wicking material covering the heat pipe 15 . Hole in helmet 16 . Thermal expansion layer actuating flap valve 17 . Substrate layer bending 18 . Aperture with air flowing through 19 . Air Space
FIG. 2 Wick Covered Heat Pipe
20 . Sweat from body and skin of wearer 21 . Evaporation and wicking of sweat and water 22 . Boiling of working fluid of heat pipe 23 . Wicking onto surface of heat pipe 24 . Heat pipe wall, impermeable to the working fluid 25 . Wicking material inside heat pipe 26 . Condensing working fluid inside heat pipe 27 . Working liquid fluid inside the heat pipe 28 . Body and skin of wearer
FIG. 3 Actuated Vents with Heat Pipe
35 . Sweat wicking off wearer 36 . Inlet moisture absorbent 37 . Inlet air flow 38 . Helmet, shell, armor or apparel exterior 39 . Working fluid bubble 40 . Condensed Working fluid 41 . Wicking material or cloth exterior of heat pipe in thermal contact 42 . Sweat or water on exterior of heat pipe 43 . Airflow exit aperture 44 . Air flowing out of exit aperture 45 . Humidity or temperature expansion layer of the laminate actuator 46 . Substrate layer of the laminate actuator 47 . Working fluid of the heat pipe 48 . Inner wicking material or cloth inside the heat pipe 49 . Wall of heat pipe 50 . Sweat of wearers skin 51 . body of wearer 52 . Fan or air pump 53 . Exterior cooling fins on dehydrator 54 . Biocide coating or particles (anti bacterial or anti fungus material) 55 . Airflow channel
FIG. 4 Actuated Air Flow with Thermally Conductive Wicking Padding
60 . Fan 61 . Moisture absorbent 62 . Airflow thru the absorbent and air flow into the channels of the padding 63 . Helmet, armor, apparel, or structure wall. 64 . Sweat 65 . Exit of apertures 66 . Exit air flow 67 . Expansion laminate material 68 . Substrate laminate material 69 . Thermally conductive padding in helmet 70 . Wicking material or fabric 71 . Sweat on body 72 . Body 73 . Sweat wicking onto exterior wick of pads 74 . Cooling fins of de-hydrator 75 . Biocide coating or particles 76 . Channels in padding 77 . Network filter or electrostatic filter
FIG. 5 Actuated Air Flow Cooling System With Supplemental Water Distribution and Body Contact Layer.
90 . Heat fins on dehydrator 91 . Absorbent beads 92 . Filter network or electrostatic filter electret fins or sheets 93 . Air flow 94 . Shell of armor 95 . Evaporating water or wick on thermal conductive padding 96 . Air flow channel 97 . Water wick pore or diffusion pore 98 . Vapor diffusion route or pore 99 . Supplemental water 100 . Exit air flow aperture 101 . Exit air flow 102 . Expansion or contraction layer of actuator 103 . Substrate film of actuator 104 . Membrane water permeable, or impermeable, fabric layer, or garment 105 . Biocide treatment or salt or water vapor reducing film 106 . Thermally conductive padding 107 . Sweat from human on wearer side of layer 108 . Sweat on wearer 109 . Water on thermally conductive padding side of layer 110 . Wearer 111 . Water on thermal conductive padding side of membrane or fabric layer 112 . Fan. 113 . Wicking material on thermal conductor 114 . Tubing 130 . Pump and bladder 131 . Supplemental cooling fluid
FIG. 6 Laminate Actuator Valve
115 . Shelf in aperture 116 . Aperture 117 . Expansion layer 118 . Notch in actuator 119 . Actuating flap 120 . Second actuating flap 121 . Substrate layer 122 . Expansion or contraction layer 123 . Cut in laminate 124 . Cut in laminate 125 . Cut in laminate
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Several typical embodiments of the invention are illustrated in the following frames. In these drawings several variations in assembly and arrangements will be shown. Please note that the drawings are drawn disproportionately to illustrate the physical features of this invention. In FIG. 1 a cross sectional view of helmet on a human head is shown. In a typical application the protective shell or helmet 2 is made of Kevlar and polyester resin lamination or steel. The padding 4 on the head of the human 13 is open cell urethane or closed cell neopream foam with a silk covering over the urethane foam. Inside the padding are flexible or rigid heat pipes. Rigid heat pipes 4 can be formed out of stainless steel or copper and the working fluid can be water, butane, or fluorocarbons such as perfluorhexane, 2-methyl perfluorpentane 1,1 difluroethane, 1,1,1,2-tetrafluroethane. Flexible heat pipes 4 , 7 , 12 can be formed out of aluminum foil sandwiched between polyester and polypropylene laminate, which typically are used to encapsulate lithium ion batteries. The working fluid in the flexible heat pipe 4 , 7 , 12 is chosen to have a boiling point at atmospheric pressure since the flexible heat pipe will be at a pressure of the surrounding atmosphere due to the flexible walls and ability to change volume, at comfortable temperature such as 28° C. of pentane. An example of a non-combustible and non-toxic working fluid is trichloromonofluomethane (Freon 11) with a boiling point of 23.8° C. The amount of working fluid in the flexible heat pipe 4 , 7 , 12 is determined precisely as to not have an excess amount such that the heat pipe will inflate to its maximum extent and not burst the seals when the heat pipe is heated above its boiling point. The choice of working fluid can be mixtures of different fluids that are aziotropes that achieve a desirable boiling point such as 5% water and pentane with a boiling point of 34.6° C. By establishing a heat pipe 4 , 7 , 12 boiling point with an impurity gas or though the pressurization via the flexible walls of the heat pipe the heat removal will only occur above the boiling point of the working fluid. This prevents the heat pipe from removing heat bellow the boiling point, so that it acts like an automatic thermostat and does not remove heat when the wearer surface 14 is cold. The heat pipes can be formed into a network to cover the head and extend out into the exterior air 7 , 12 , either through the helmet via 15 a vent hole or around the rim of the helmet shown in FIG. 1 . The heat pipes will be filled with the working fluid and a wicking material 4 to redistribute the liquid working fluid by capillary action back to the heat source. These wicking materials can be silk or finely woven stainless steel mesh. In some situations such as in a helmet the wicking material inside the heat pipe 4 can be deleted if the helmet 2 or application is oriented in gravity such that the liquid return of the working fluid is back down to the heat source (the head 13 ). This can lead to a beneficial situation that if the outside air 8 , is hotter than the human 13 there will be no liquid on the high area of the heat pipe 7 and it will be able to boil fluid and transfer heat from the outside environment to the inside the helmet 3 , 14 . This can be very important to not transfer heat into the human 13 , such as when there is fire on the outside of the helmet 2 or armor. To control the airflow 1 through the helmet laminate actuators 5 , 6 , 9 , 11 are made of two layers such as a polyester substrate film 6 which has a low to negative thermal expansion coefficient and the temperature or humidity expanding material layer 5 such as Nylon (Wright Coating Co., 1603 North Pitcher St., Kalamazoo, Mich. 49007), Nafion (Sigma-Aldrich Co., 3050 Spruce St., St Louis, Mo., 63103) or an aromatic polyetherketone resin having protonic acid group (US Patent application 20040191602 Mitsu Corporation, 580-32 Nagaura, Sodegaura-City, Chiba 299-0265, Japan), for expansion with high humidity or polyethylene for expansion with high temperatures. The laminate actuators 5 , 6 , 9 , 11 can be placed such that they block the airflow out 10 of the exit apertures 15 when the interior of the helmet is low humidity or cold. When the humidity rises or the temperatures rise the apertures open 5 , 6 , 9 , 11 . With the apertures open air flows 1 , 10 through channels 3 formed in the wick covered padding 4 , 14 and evaporation of sweat or water added to the padding in the helmet. Air flowing 1 over the exterior of the heat pipes cools the heat pipes and removed heat from the surface 14 of the wearer 13 . To draw air out though the vent 15 in the top of the helmet 2 a venturi flow 10 constriction and hole 15 can be formed with the heat pipe 7 or a vent cover 16 , 17 . The high velocity flow causes the pressure to be lowered and draw air out of the top of the helmet 2 . Other arrangements such as with motorcycle helmets is to direct the vent cover open such that face away from the air flow 8 direction as illustrated vent 16 , 17 and draw air through the aperture 18 the actuator 16 , 17 when opened. To moderate or control the cooling of the heat pipe that is outside the helmet a laminated actuator cover or variable insulation layer 16 , 17 can be placed over the heat pipe 7 . This laminate actuator layer or layers 16 , 17 can react to temperature alone, in contrast to the laminate actuators 5 , 6 , 9 , 11 on the inside of the helmet or body armor that react to humidity or temperature. These exterior laminated actuators, as an example, are made with a lamination of polyester substrate layer 17 with a low coefficient of thermal expansion and a polyethylene layer 16 with a high thermal expansion coefficient. The laminate actuator sheet 16 , 17 , fibers, or polymorphic surface are cut to form flap valves or random hair like actuation. Flap actuators 16 , 17 and apertures 18 can be formed to close and block air flow through the aperture 18 . In both cases the laminate actuators interfere with flow of air and flow over heat from the heat pipe 7 . These thermal actuated laminate actuators 16 , 17 placed on the outside of the helmet or armor 2 can be a fabric like material that expands and traps air 19 when exterior temperatures or low and allows air flow 18 when temperatures are high. Thermally conductive materials such as graphite sheets, fibers, copper wires, copper foils, aluminum wires, or aluminum oxide can be incorporated into the padding foam 4 , 14 or substituted for the heat pipes 7 to move heat away from the wearer to the water evaporating areas or outside the helmet 2 . The thermally conductive materials or rigid heat pipes 12 exposed to the outside air flow 8 have the disadvantage that if they are taken to the outside the helmet can remove or add heat to the wearer, but are simple to construct compared to the heat pipes. To correct this disadvantage a laminate actuator cover 16 , 17 , as shown covering the heat pipe on the top of the helmet 7 , can thermally insulate the heat pipe 7 when temperatures are low.
In operation of the helmet air flows 1 into the channels of the padding 14 , 4 of the helmet removing some heat through the padding by heating up the incoming air, if the outside air is cooler than the wearer. Additional cooling occurs from the evaporation of sweat which is wicked 14 through silk or COOL MAX® (Intex Corporation, 1031 Summit Ave. Greensboro, N.C. 27405) onto the surface of the padded heat pipes into the air flow channels 3 . The air flow 1 is blocked by the laminate actuators 5 , 6 , 9 , 11 if the humidity or temperatures are low in the helmet 2 . If the humidity or temperatures are high the laminate actuators 5 , 6 , 9 , 11 open and air flows 1 and evaporative cooling occurs and heat is removed from the surface of the wearer 14 via the heat pipes of thermally conductive pads 4 . The moisture laden air flow exits 10 from the helmet though vent holes 15 or out though the back rim valves 11 of the helmet 2 . Air flow movement is expected to be driven by thermal convention or forced by the motion of the wearer on a motorcycle or vehicle. Later drawings will show how the air flow can be forced through the padding channels with a fan or pump.
In FIG. 2 a cross sectional view of the wick covered heat pipe is shown in contact with a wearer's skin or body. In this diagram the heat pipe 24 , 25 , 22 , 26 , 27 draws sweat 20 off the surface of the wearer 28 where the heat pipe makes contact with the wearer's skin. The sweat 21 wicks over the surface of the heat pipe through the silk covering of the heat pipe 23 . On the surfaces of the heat pipe that is exposed to flowing air the sweat 21 evaporates and the cools the surface of the heat pipe. Inside the heat pipe the working fluid condenses 26 and delivers heat through the heat of condensation of the working fluid 27 . While on the contact area with the wearer 28 the working fluid liquid boils 22 and removes heat from the surface of the wearer 28 via the heat of vaporization. Heat can also be removed from the surface of the wearer 28 through the heat pipe to the cooler surroundings without evaporating sweat 21 off the surface of heat pipe. The heat pipe walls 24 are formed by heat sealing an aluminum layer or copper layer lined polyester polyethylene sandwich material (Vendor address). An inner wicking liner 25 is placed inside the heat pipe such as silk fabric, polyester fabric, open cell urethane foam, or fine woven stainless steel mesh.
In FIG. 3 a wick covered heat pipe inside a helmet or armor shell with air flow and actuating valve are shown. In this example the heat pipe 49 is part of the padding of the helmet or armor 38 and is pressed against the wearer 51 . Sweat 50 from the wearer 51 is wicked from the surface of the skin 35 and through the wicking fabric 41 of covering the heat pipe 49 . The sweat 42 wicks to the surfaces of the heat pipe/padding 41 to be exposed to the air flow channels 55 in the helmet 39 . The air flows 37 through an air intake and out 44 through a vent port 43 . In this example a de-humidifier 53 filled with a material such as zeolite beads or a salt 36 that absorbs water vapor from the air. With this absorption the heat of condensation and heat of interaction is delivered on the zeolite or salt 36 . This heat is then conducted to heat fins 53 and dissipated into the surroundings. A fan or pump 52 can be used to force air flow 37 through the dehumidifier and air flow channels 55 . If the wearer 51 is traveling through the air their may be sufficient rammed air pressure and subsequent air flow 37 through the dehydrator and the air flow channels 55 to cool the wearer 51 . Thus, the fan or pump 52 may not be needed. In situations where the wearer 51 is stationary, the fan or pump 52 may be necessary to achieve sufficient air flow to cool the wearer 51 . A laminate actuator valve 43 , 45 , 46 is shown in this example. It is formed by a lamination of polyester plastic film 46 coated at the bending areas with, Nylon, aromatic polyetherketone resin, or other humidity swelling plastic film 45 . Temperature actuation could be enabled by laminating on the actuator a plastic film 45 such as polyethylene which has a high thermal coefficient of expansion. Both thermal expansion and humidity expansion materials could be laminated onto the actuator substrate film 46 to produce temperature and humidity actuation with changes in temperature and humidity. The laminate actuator 45 , 46 covers its aperture 43 when humidity or temperatures are low and uncovers the aperture 43 when humidity or temperatures are high. This allows air to flow 37 though the air channels in the padding 55 and out 44 through the vent hole 43 . This in turn allows sweat 42 to evaporate and cool the surface of the heat pipe 41 , 49 and the heat pipe 49 in turn cools the surface of the wearer 51 , by boiling a working fluid 47 . A working fluid 47 , such as pentane is wicked onto the inner surfaces of the heat pipe 49 with a silk or polyester liner fabric 48 . The working fluid 47 boils 39 , removing heat, at the thermal contact of the wearer 51 , and then deliverers' heat by condensation 40 to the sweat 42 in the wick cover 41 on the heat pipe 49 when it condenses 40 . Then as the air is flows 37 , 44 past the water wicked surface 42 on the outer surface of the heat pipe 49 heat is removed by vaporization of the sweat 42 . A biocide such as silver coatings or photoreactive titanium dioxide particles or films 54 are deposited into and onto the wicking fabric 41 on the heat pipe 49 . The biocide 54 is added to block the growth of bacteria or fungus on the wicking surfaces 41 because they are moist and may be impregnated with dead skin, body fluids, and sweats from the wearer 51 and provide ideal growth environment for bacteria and funguses.
In FIG. 4 wick covered thermally conductive padding dehydrating air flow and laminate actuator are shown. In this example the padding 69 on the wearer 72 is thermally conductive and a conduit for heat flux such as radiant heat transfer, fluid circulation (convection), electron conduction (metals), and phonon heat transfer (electrical insulators). The thermal conduit padding 69 can be open cell urethane foam loaded with graphite, aluminum oxide, or copper powder, closed cell silicone rubber, closed cell neopreame rubber, closed cell polystyrene foam, or closed cell urethane rubber foam. The padding 69 can also be a bladder filled with a, powder, beads, liquid, or jelly such as silicone gel Beta Gel (Geltec Corporation, Ltd, Shinagawa TS Bldg. 2-13-40 Konan Minato-ku, Tokyo 108-0075, Japan). Materials such as graphite powder, graphite fibers, carbon nano-tubes, aluminum wires, aluminum fibers, magnesium powder, silver powder, silver wires, copper wires, copper powder, silicon carbide powder, zirconium oxide powder, aluminum oxide powder, and water gels, can be incorporated into the padding 69 to increase the thermal conductivity. The thermal conductive material 69 can act to homogenize the temperature environment contained behind the armor which can be useful when certain parts of the armor are exposed to different temperatures and heat loss environments such as in gloves and shoes, where the finger tips and toes are cold and the palms and ankles may be hot. There are physiological situations where the human or animal body reduces or has reduced blood flow to the extremities and the external redistribution of heat to the extremities can be useful. The padding 69 is covered with a wicking material 70 such as silk fabric or hydrophilic treated polyester fabric such as COOL MAX®. The wicking fabric 70 can be coated with a photo catalytic titanium oxide coating (TPXsol, KON corporation, 91-115 Miyano Yamauch-cho, Kishima-gun Saga prefecture, Japan) 75 to achieve a high surface energy and wet-ability. This wetting coating 70 such as photo catalytic coating can also act as a biocide killing bacteria and fungus on contact. Silver coatings 75 on the wicking material 70 can also be used as a biocide. The air inlet contains loosely packed beads or cadged beads of moisture absorbent material 61 such as a zeolite, silica gel, or calcium oxide that remove moisture from the inlet air as it flows through. This air inlet bed 61 , 77 can also act to filter out insects, dust, rain, snow, bacteria, and dirt from the air flowing into the channels in the padding 76 and incorporate techniques such as network mesh filter such as expanded Teflon and/or electrostatic filter such as parallel sheets of charged electrets of silicone rubber 77 . The dehydration of the air flow 62 may be useful in high humidity environments but may be less useful in environments where the relative humidity is below 50%. The heat of condensation of the moisture and the reaction of the moisture with the moisture absorbent 61 is conducted to the armor walls 63 of the dehydrator and dissipated to the environment through cooling fins 74 . A fan or pump 60 is used to push air through the dehydrator particles 61 and channels 76 in the padding. The fan or pump 60 could be linked to the laminate actuator 67 , 68 to only operate when the laminate actuator valve 65 , 67 , 68 has opened and air will flow through the system. In some situations thermal convection of air flow or just the motion of the wearer may be sufficient to move air through the air channels 76 to effectively cool the wearer 72 . A laminate actuator valve 65 , 67 , 68 is shown in this example formed by a lamination of a polyester or polyimide plastic film 68 coated at the bending areas with Nylon, aromatic polyetherketone resin or other humidity swelling plastic film 67 . Temperature actuation could be enabled by laminating onto the substrate film 68 an actuating plastic film 67 such as polyethylene which has a high thermal coefficient of expansion. Both thermal expansion and humidity expansion materials could be laminated onto the substrate film 68 to produce temperature and humidity actuation with changes in temperature and humidity. The laminate actuator 67 , 68 covers the opening 65 when humidity or temperatures are low and uncovers the opening 65 when humidity or temperatures are high. This allows airflow 62 , 66 though the channels 76 in the padding 69 and out through the vent hole 65 . This air flow allows sweat 64 to evaporate and diffuse water molecules into the dry incoming air, and cool the wicking surface 70 of the thermally conductive pads 69 which in turn cools the surface of the wearer 72 . Sweat 71 from the body 72 is wicked through the cloth cover 70 to the outer surfaces 64 of the thermal conductor 69 . When the temperatures or humidity inside the helmet 63 is low the laminate actuator valve 65 , 67 , 68 closes and air flow 66 is blocked or impeded. This air flow blockage or impedance reduces the heat flux lost from evaporation, diffusion, and convection and maintains comfortable conditions inside the helmet 63 .
In FIG. 5 the cooling system with supplemental water supply for evaporation and a fabric or membrane layer between the wearer and the thermal conductor is shown. In this embodiment of the invention the features of the wicking material 113 on thermally conductive padding 106 is shown. A humidity or temperature activated laminate actuator valve 102 , 103 are shown covering an exit aperture 100 in the armor shell 94 . An air flow intake fan 112 with dehydrator beads bed 91 and conduction and convection cooling fins 90 on the exterior of the dehydrator is shown. In certain situations supplemental evaporative cooling may be very desirable for this invention. These are situations where the cooling needs tax the wear to sweat sufficiently or the wearer needs to be isolated from the external air such as in hazardous environmental suits. Thus, to provide this higher cooling capacity evaporative cooling water can be distributed onto the wick 113 on the thermally conductive padding 106 through tubes such as polyurethane (Stevens Urathane, 412 Main Street, Easthampton, Mass. 01027) or silicone rubber tubing 114 (Silicone Specialty Fabricators, 222 Industrial Park Drive, Elk Rapids, Mich. 49629). A network of tubing with open exits or tubes with small pores, 98 , 97 can distribute water to the wicking material 113 on the thermal conductors 106 in the air flow passages 96 . Other alternative methods of delivering the supplemental water is through a water permeable membrane such a thin walled polyurethane tubing 114 or though a hydrophobic porous water vapor permeable membrane of expanded Teflon or GORE-TEX® (W.L. Gore & Associates, Inc., 295 Blue Ball Road, Elkton, Md. 21921). In all three cases the water distribution system tubes 114 should be in physical contact or thermal contact with the thermal conductive padding 106 to be able to conduct heat from the wearer 110 to the evaporative cooling sites 95 . These supplemental fluid tubes 114 could also be sealed tubes or a portion being sealed and the chilled fluid or heated fluid 124 circulated throughout the helmet or body armor 94 . A pump 123 , such as a hand squeeze elastic bladder, could be used to circulate or oscillator the fluids into the tubes 114 . Another configuration that will be used in many situations is that the wearer 110 has a wicking fabric 104 covering their skin such as silk or micro fiber polyester COOL MAX® and the sweat route 108 , 107 , 109 , 111 and thermal contact must go through this fabric covering. This layer interface between the wick covered thermal conductor 113 , 106 and the wearer 110 may also be a membrane 104 such as polyurethane or silicone rubber membrane to allow water 107 , 109 to diffuse through but not allow bacteria or viruses through. This membrane 104 could be a porous hydrophobic liquid water blocking membrane that would allow vapor through while not allowing liquid water to flow through such as with expanded Teflon, or GORE-TEX® fabric. The membrane 104 could also be an impermeable barrier such as neoprene rubber or stainless steel plate where only heat removal is desired. When the water transport 108 , 107 , 109 , 111 from the wearer 110 to the wick covered thermal conductor 106 , 113 , 95 is done with a selectively permeable membrane 104 such as an cellulose nitrate, osmotic membrane (Membrane Process Engineering, 3-3-3 Akasaka, Minato-Ku, Tokyo, Japan) or a vapor transport membrane such as expanded Teflon a salt or water vapor pressure reducing material such as sodium chloride, cotton, titanium dioxide, or Nafion polymer electrolytes 105 can be coated or incorporated into the wicking material on the thermally conductive padding 106 . This creates a vapor pressure gradient, surface tension energy gradient, with the higher surface tension energy on the evaporation sites 95 , or ionic concentration gradient to draw water from the wearer to the wicking covering material 113 . This can keep the wearer's surface 110 dry and comfortable. In operation the supplemental water 99 distribution 97 , 98 from the tubes 114 and wicking materials 113 could be provided for on demand or thorough sensors built into the laminate actuators 102 , 103 that sense excessive temperatures. The fan 112 can also be activated through the same laminate actuator sensor 102 , 103 . When temperatures are low the laminate actuator could cover the aperture 100 and stop the evaporative cooling 95 , 98 and the fan 112 would shut off to thermally insulate and conserve heat of the wearer 110 . In operation air is drawn through the water absorbent 9 and electrostatic filter 92 with a fan 112 . This insures that the air flow 93 is dry and clean. The airflow 93 through the channel between the conductive pads 106 and armor 94 . Evaporation of water occurs on the surface of the wick 113 and the supplemental fluid tubes 98 . If the temperatures are high the laminate actuators 102 , 103 will open and let the exit air flow 101 through the aperture 100 .
In FIG. 6 a sample of sheet of laminate actuator valves is shown. The constructions of these laminate actuators are formed out of two or more films of materials 121 , 122 that have different expansion properties and are laminated together. The different expansion properties of the two films 121 , 122 lead to shear stress between the two films. To relieve this stress laminated films will curl once they find a preferential curl or non-constrained direction. If the laminate sheet is cut into patterns such as the three right angle cuts 123 , 124 , 125 as shown in FIG. 6 the laminate will curl into a flap arrangement 117 , 119 , 120 that has a preferential fold determined by the geometry of the cut pattern and the laminated material deposits. The aperture 116 left by the cut can act as the aperture of a valve when the flap presses back into the aperture 116 . A shelf 115 can be cut or formed into the substrate 121 and the flap 118 such that the flap can only open one direction and creates a seal with the aperture 116 when the actuation goes in the opposite curl direction. An example of a laminate actuator construction is to thermally bond a 25 micron thick sheet of polyester 121 with a low thermal expansion coefficient to a 75 micron thick sheet of polyethylene 122 with a high coefficient of expansion. In this particular example the flaps or actuators 119 , 120 would curl open when hot and curl closed when cooled to press the notch on the flap 118 to the shelf 115 on the aperture 116 . Laminated actuator structures can be cut with many patterns such as two right angle cuts, three angles cuts that form flaps and apertures. Laminate actuators can be formed and cut on two or three dimensional surfaces such as fibers, cylinders and polymorphic surfaces. Our patent Application U.S. 60/765,607 describes a host of cut patterns, geometries of laminate actuator valves. These valves are auto-actuating valves and auto-changing structures that change with changes in temperature, relative humidity, chemical, electrical, and light environments. Mesh support materials or shelves 115 can be laminated onto the apertures 116 to create screens as flap stops to prevent the flap from curling through the aperture and opening in the opposite direction. These laminated actuator valves and structures can range in size from many centimeters nanometer dimension hairs. The actuators can be effective as hairs that actuate and created impedance to fluid and thermal flow or fluff layers of actuators to effectively increase thermal insulation by pushing each layer apart to create stagnant cavities of fluid (gasses or liquids). The laminate actuated structures can also include coiling and uncoiling fibers and strips.
Another construction example of a laminate actuator is to form the laminated layers with a porous polyester substrate or polyethylene 121 and a temperature or humidity expanding material layer 122 such as Nylon, Nafion, or an aromatic polyetherketone resin having protonic acid group for expansion. The porosity of the substrate 121 can enhance the adhesion between the layers and also increase the sensitivity to moisture by allowing diffusion through the substrate membrane 121 to the expanding material layer 122 . The expanding material layer 122 is coated onto the one side of the polyester substrate 121 . Specific deposit patterns and thicknesses of the expanding layer 122 can be used to efficiently utilize the expansion polymers and create effective actuation patterns. Additional layers of coatings and electrodes such as piezoelectric materials can be deposited on the substrate 121 or expansion layers 122 such as a piezoelectric material of polydifluoethylene (PDVF), and electrodes such as vapor deposited platinum films, or sliver print. These additional coatings can provide for functions to act as sensors to the relative humidity, temperature, or be electrically stimulated to open the actuators or cause them to oscillate and pump air flow.
Physical elements of this invention include:
1. Wick contact with living body 2. Heat pipe or thermal conductor or conduit in contact with living body 3. Air flow in channels 4. Evaporative cooling in the air flow channels and on heat pipes or thermal conductors. 5. Using flexible or elastic heat pipes pressure equilibrium with the external atmosphere to set the boiling point of the working fluid. 6. Using impurities in the heat pipe working fluid to set the boiling point of the working fluid inside the heat pipes. 7. Heat pipes without wicks and gravity orientation to act as one way heat delivery systems and avoid heat flow back to the wearer. 8. Humidity or temperature auto-reactive laminate actuator structures and/or valves to control air flow to try and achieve more constant temperature or humidity conditions, by impeding air flow when dry or cold and reducing impedance when humid or hot. 9. Humidity or temperature auto-reactive laminated actuator structures to achieve self adjusting variable thermal insulation to achieve more constant temperature by increasing thermal resistance when dry or cold and decrease thermal resistance when humid or hot. 10. Covering the living body padding with a plurality of reactive laminate actuator valve arrays or actuated structures such as curling hairs. 11. Covering the exterior of the helmet or body armor to achieved self adjusting variable thermal insulation. 12. Delivering extra liquid water or a fluid for evaporative cooling inside the helmet or armor to the wicking padding on the thermal conductors or heat pipes. 13. Fluid flow systems that can also be used to deliver hot or cold fluids to the inside the helmet or armor. 14. Delivering liquid water and evaporation through a membrane for cooling inside the helmet or armor. 15. Coating the wicking materials with biocides and fungicides. 16. Using a fan or pump to push air flow or fluid flow through the channels in the helmet or body armor. 17. Using a moisture absorbent to remove moisture from the air entering the helmet or body armor. 18. Using a filter and/or electrostatic filter to remove contaminants from the air flowing into the helmet or body armor. 19. Using a wicking covering over the living body. 20. Using a selectively permeable membrane between the living body and the air flow passages. 21. Using ionic concentration gradients to draw water away from the living body surface. 22. Using surface tension gradients to draw water away from the living body surface. 23. Using the position and geometry of air flow vents with respect to the helmet or body armor air flow environment or gravity orientation to achieve high air flow rates and convective air flow rates in the channels in the helmet or body armor. 24. Using a pump to move supplemental fluids into the helmet or body armor to for supplemental evaporative cooling or circulating cooled or heated fluids.
While this invention has been described with reference to specific embodiments, modifications, and variations of the invention may be constructed without departing from the scope of the invention. | The lack of air flow under body armor, helmets, and thick garments can lead to excessive moisture build up and discomfort on the wearers body due to lack of heat removal and effective evaporation of sweat. By incorporating wick covered heat pipes or thermal conductors with air flow channels in the apparel contact area between the garments, helmets, and body armor the effectiveness air flow cooling and evaporation of sweat can be restored. Humidity or temperature auto-actuated bi-material valves are used to control this air-moisture-heat flow to achieve a controlled comfortable humidity-temperature environment and avoid excessive cooling. Supplementary air pumps, filters, dehydrators, fluid pumps, heating fluids, and cooling fluids may be incorporated to enhance the effectiveness. Biocides and hydrophilic materials are also incorporated on the wick coverings to avoid biological growth and maintain performance to achieve a healthy environment for the wearer. | 48,274 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser. No. 10/389,448 filed Mar. 14, 2003, incorporated herein by reference. Cross-reference is also made to U.S. patent application Ser. No. 09/526,679 filed on Mar. 16, 2000, now U.S. Pat. No. 6,553,604, and Ser. No. 09/576,590 filed on May 22, 2000, now U.S. Pat. No. 6,564,416, both of which are assigned to Gillette Canada Company.
FIELD OF THE INVENTION
[0002] The invention relates generally to the field of oral care, and in particular to toothbrushes. More specifically, the invention relates to a toothbrush head having one or more pivoting tufts of bristles, the head having two portions that can move independent of each other.
BACKGROUND OF THE INVENTION
[0003] A Japanese patent document having an application number of 3-312978 discloses a toothbrush having a multiplicity of tufts of nylon bristles. In a first embodiment shown in FIGS. 1, 2 and 3 of the document, a plurality of cylindrical recessed sections in the head are set orthogonally to the longitudinal axial direction of a shank and are formed at equal intervals. Column-shaped rotary bodies 5 are respectively contained in the recessed sections. On the peripheral surfaces of the rotary bodies 5 , along the axial direction, projected strip sections 5 a are formed, and they are set in a state that they are positioned at the opening sections of the recessed sections. At the opening sections of the recessed sections, contact surfaces to be positioned on both the sides are formed. At both the ends of the upper surfaces of the projected strip sections 5 a , nylon bristles 6 are arranged to be vertically erected.
[0004] As shown in FIG. 3 of the document, the arrangement described above allows bristles 6 to rotate during use of the brush. A problem with this brush is that two tufts of bristles are secured to each strip section 5 a and thus must rotate in unison. As a result, an individual tuft of bristles cannot rotate independently of its “partner” tuft. The individual tuft may thus be prevented from achieving optimal penetration between two teeth during brushing because the partner tuft might contact the teeth in a different manner and interfere with rotation of the individual tuft.
[0005] FIGS. 4, 5 and 6 of the document disclose a second embodiment in which each tuft of bristles is secured to the head by a ball and socket type arrangement. While this embodiment allows each tuft of bristles to swivel independent of the other tufts, it does have disadvantages. If a tuft of bristles is tilted out towards the side of the head and that tuft is positioned near the interface between the side and top surfaces of the teeth, chances are increased that the bristle tips will not even be in contact with the teeth during brushing. Further, the random orientation in which the tufts can end up after brushing detracts from the attractiveness of the brush.
[0006] The Japanese reference also discloses that the brush head is made of a unitary structure. As such, water cannot flow through any central portion of the brush head, thereby inhibiting the cleanability of the brush. Further, the unitary head structure does not allow different portions of the head to move independently of each other. Accordingly, the bristle tufts extending from the tuft cannot accommodate the varying tooth surfaces as well as a brush in which the head has two or more portions that can move or flex independent of each other.
SUMMARY OF THE INVENTION
[0007] The present invention is directed to overcoming one or more of the problems set forth above. Briefly summarized, according to one aspect of the present invention, a toothbrush head has a tooth cleaning element extending from the head. The head is divided into at least two portions which can be moved independent of each other. The tooth cleaning element is rotatable relative to that portion of the head from which it extends.
[0008] According to another aspect of the invention, a tooth cleaning element includes one or more tooth cleaners, a base support, and an anchor pivot. One end of the one or more tooth cleaners is secured to a first end of the base support. One end of the anchor pivot is secured to a second end of the base support. The anchor portion has a larger section further from the base support than a smaller section of the anchor portion.
[0009] In accordance with a third aspect of the invention, a method of making a toothbrush head includes molding a plastic toothbrush head in a mold. The head has two distinct portions which are spaced a predetermined distance from each other. The head is removed from the mold. At least that part of the head where the two head portions connect is heated. The two head portions are moved towards each other. At least that part of the head where the two head portions connect is cooled such that the two head portions will now remain in positions where they will be spaced apart a distance which is less than the predetermined distance.
[0010] According to a fourth aspect of the invention, a method of making a toothbrush head includes molding a plastic toothbrush head in a mold. The head has at least one hole therein which extends all the way through the head. The head is removed from the mold. A tooth cleaning element is inserted into the hole
[0011] These and other aspects, objects, features and advantages of the present invention will be more clearly understood and appreciated from a review of the following detailed description of the preferred embodiments and appended claims, and by reference to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective view of the toothbrush head of FIG. 1 ;
[0013] FIG. 2 is a top view of the head of FIG. 1 ;
[0014] FIG. 3 is a side view of the head of FIG. 1 ;
[0015] FIG. 4 is a bottom view of the head of FIG. 1 ;
[0016] FIG. 5 is a side view of the head of FIG. 1 showing one of the head portions flexing;
[0017] FIG. 6 is a top view of the head of FIG. 1 with the two head portions separated from each other;
[0018] FIG. 7 is a top view of the head of FIG. 1 after the head portions have been positioned closer to each other;
[0019] FIG. 8 is a front view of a pivoting tuft taken along the lines 8 - 8 of FIG. 13 ;
[0020] FIG. 9 is a side view of the pivoting tuft of FIG. 8 taken along lines 9 - 9 ;
[0021] FIG. 10 is a top view of one of the holes in the head for receiving the pivoting tuft (see FIG. 6 );
[0022] FIG. 11 is a sectional view of FIG. 10 taken along lines 11 - 11 ;
[0023] FIG. 12 is a sectional view of FIG. 10 taken along lines 12 - 12 ;
[0024] FIG. 13 is a side view of the head of FIG. 1 (a portion is removed to facilitate viewing) and a pivoting tuft prior to insertion into the head;
[0025] FIG. 14 is a side view of the head of FIG. 1 (a portion is removed to facilitate viewing) and a pivoting tuft after insertion into the head;
[0026] FIG. 15 is a side view of the pivoting tuft showing its motion;
[0027] FIGS. 16 A-C are sectional views of FIG. 15 taken along the lines 16 A-C- 16 A-C;
[0028] FIG. 17 is a perspective view of a tooth cleaner in the form of a ribbed fin; and
[0029] FIG. 18 is a side view of the ribbed fin of FIG. 17 .
DETAILED DESCRIPTION
[0030] Beginning with FIGS. 1-5 , there is shown a toothbrush head 16 which extends from a neck 14 which extends from a handle (not shown) to form a toothbrush. The type of handle is not germane to the present invention. The head and handle are preferably made of polypropylene. The head has a serpentine split 18 which divides the head into two portions 20 and 22 . An end of the split 13 near neck 14 is preferably circular in shape (see FIG. 2 ). As shown in FIG. 5 , the split in the head allows portions 20 and 22 to flex or move independent of each other during use of the toothbrush, thus facilitating cleaning of the teeth.
[0031] Split 18 can also be defined as an opening in the head between head portions 20 and 22 . This opening allows water to flow through the head, thereby enhancing cleaning of the top head surface which typically gets caked with toothpaste in spite of efforts to rinse the head clean.
[0032] Head portion 20 includes a projecting part 24 which fits (at least partially) into a recess 26 (see FIG. 6 ) defined by portion 22 . Projecting part 24 has several tufts of bristles extending from it (to be described in further detail below) and is surrounded on three sides by head portion 22 .
[0033] Referring now to FIGS. 2 and 3 , each of the tufts of bristles on head 16 will be described. A first pair of tufts 28 are located towards the free end of the head, one on each head portion 20 , 22 . Each tuft has bristles (tooth cleaners) which preferably are each made of polybutylene-terepthalate (PBT) and have a diameter of 0.007 inches. The shortest bristles in tuft 28 have a length of 0.420 inches with the remaining bristles increasing in length steadily to a tip of the tuft. Each tuft tilts away from the handle by an angle of preferably about 12 degrees relative to that portion of the surface of the head from which it projects. As shown in FIG. 2 , tufts 28 have a larger cross-section than any other tuft on the head.
[0034] A second group of tufts are pivoting tufts 30 (the only tufts on the head which are rotatable). There are four tufts 30 on each head portion 20 , 22 which are located towards the outside of the head. Each tuft 30 can pivot up to about 15 degrees to either side of a vertical position on the head, more preferably being able to pivot up to about 8 degrees to either side of a vertical position on the head. The pivoting of tufts 30 is roughly towards or away from neck 14 . Each tuft 30 includes a base support 32 made of polypropylene. The bristles are made of polyamid 6.12, have a diameter of 0.008 inches and extend 0.420 inches above the base support.
[0035] A third group of tufts 34 extend perpendicular to the head. There are four tufts 34 on each head portion 20 , 22 which alternate with tufts 30 . When viewed from the top ( FIG. 2 ) the tufts are oval in shape (similar to tufts 30 but larger). In other words, the tufts 34 and 30 have oval shaped cross-sections. Each tuft 34 has bristles which are made of polyamid 6.12, have a diameter of 0.006 inches and extend above the head by about 0.385 inches.
[0036] A fourth group of tufts 36 are located towards the inside of the head. There are two such tufts on each head portion 20 , 22 . Each tuft 36 extends perpendicular to the head. The bristles of tuft 36 have a diameter of 0.006 inches, are made of polyamid 6.12 and rise about 0.360 inches above the head.
[0037] A fifth and final group of tufts 38 are also located towards the inside of the head (away from a perimeter 21 of the head). There are 4 pairs of tufts 38 . In each pair one tuft is closer to neck 14 than the other tuft. In each pair of tufts 38 , (a) a base of one tuft is closer to a first side of the head and this one tuft leans towards a second side of the head, and (b) a base of the other tuft is closer to the second side of the head and this other tuft leans towards the first side of the head. As such, the tufts in each pair lean across each other. The angle of tilt towards the side of the head is about five degrees. Each tuft 38 bristles which are made of PBT, have a bristle diameter of about 0.007 inches and extend about 0.460 inches above head 16 . Each tuft 38 has an oval cross-section with a long dimension of the oval being oriented in the direction of tilt.
[0038] The bristles used on the head can be crimped (see U.S. Pat. No. 6,058,541) or notched (see U.S. Pat. No. 6,018,840). Other types of tooth cleaners besides bristles can be used. For example, a tuft of bristles could be replaced by an elastomeric fin. The US patents listed in this paragraph are incorporated herein by reference.
[0039] Turning now to FIG. 6 , a description will now be provided as to how the toothbrush (head) is made. In a first step, the head, neck and handle of the toothbrush are injection molded in a mold. During this injection molding step, tufts 28 , 34 , 36 and 38 are secured in the head by a hot-tufting process. Hot-tufting processes are notoriously well known by those skilled in the art (see e.g. U.S. Pat. Nos. 4,635,313; and 6,361,120; British patent application 2,330,791; and European patent application 676,268 A1).
[0040] Briefly, hot-tufting involves presenting ends of a multiplicity of groups of plastic filaments into a mold. Each group of filament ends inside the mold is optionally melted into a blob. Each filament group is cut to a desired length (either before or after being introduced into the mold) to form a tuft of bristles. The mold is closed and molten plastic is injected into the mold. When the plastic solidifies, it locks one end of the tufts of bristles into the head of the toothbrush.
[0041] It can be seen in FIG. 6 that the opening 18 between head portions 20 and 22 is much wider at this point than in the heads final form (see FIG. 2 ). In other words, head portions 20 and 22 are spaced a predetermined distance (preferably at least about 1 mm) from each other. Further, through holes 40 are created during the molding step for receiving pivoting tufts 30 at a later point in the manufacturing process. Holes 40 will be described in greater detail below.
[0042] With reference to FIG. 7 , after the toothbrush is removed from the mold, heat 42 is applied to the head near the neck and to part of the neck (hereinafter the neck). The heat can be applied in a number of ways including hot air, radiant heating, ultrasonic or convection (e.g. hot oil) heating. Here the heat is shown being applied to the sides of the neck. It is preferable to apply the heat to the top and bottom surface of the neck. The heat brings the plastic up to 1.0-1.12 times its glass transition temperature (when temperatures are measured in the Kelvin scale). The plastic should not be heated above 1.12 times its glass transition temperature in order to avoid damaging the plastic. More preferably, the plastic is heated to about 1.03-1.06 times its glass transition temperature (measured in degrees Kelvin). The glass transition temperature for polypropylene is about 100 degrees centigrade whereas the glass transition temperature for copolyester and polyurethane is about 65 degrees centigrade.
[0043] Pressure 44 is then applied to head portions 20 , 22 to move the portions towards each other. Once head portions 20 , 22 are in the position shown in FIG. 2 , the heated portion of the head/neck is cooled by, for example, exposing the heated portion to a cold gas or liquid. If room temperature air is used to cool the neck, such air should be applied for about 20-25 seconds. This has the effect of forming the two head portions into their final positions.
[0044] In order to achieve short process times, the highest temperature heat source which will not damage the plastic should be used. If too hot a heat source is used and/or if the heat is applied for too long, the plastic can be damaged. If the heat source is not hot enough, the process will take too long and/or head portions 20 , 22 will not remain in their final desired positions. If the head/neck are made of polypropylene and hot air is used to heat the neck, (a) the heated air should be at a temperature of about 170 degrees centigrade and should be applied to the neck for about 70 seconds, (b) the polypropylene should be raised to a temperature of about 140 degrees centigrade, and (c) a nozzle which applies the hot air to the neck should be about 10 mm from the neck.
[0045] If copolyester or polyurethane is used as the material for the head neck, (a) the heated air should be at a temperature of 250 degrees centigrade and should be applied to the neck for about 10 seconds, (b) the material should be raised to a temperature of preferably 95-100 degrees centigrade, and (c) a nozzle which applies the hot air to the neck should be about 15-20 mm from the neck.
[0046] Heating the respective materials above for the time indicated allows the material to be softened and mechanically bent into its final form. Exceeding the heating times above could cause the material to overheat and become damaged.
[0047] Turning to FIGS. 8 and 9 , each pivoting tuft 30 has a multiplicity of bristles 46 , a base support 48 and an anchor pivot 50 . The bristles are secured to and extend from a first end 52 of the base support while a first end 54 of the anchor pivot extends from a second end 56 of the base support. The base support and anchor pivot are preferably a unitary structure made of the same material. Anchor pivot 50 includes a first portion 58 near the first end 54 and a second portion 60 near a second end 62 of the anchor pivot. First portion 58 is smaller in an X an Y dimension than second portion 60 . Base support 48 is larger in an X and Y dimension than second portion 60 of the anchor support. Second portion 60 includes a pair of lips 63 . The anchor pivot defines an opening 64 therethrough.
[0048] Tuft 30 can also be made by a hot-tufting type process as described above. Instead of injecting plastic into the mold to form a toothbrush handle, neck and head, the plastic is injected into a mold to form base support 48 and anchor pivot 50 , capturing bristles 46 when the injected plastic cools.
[0049] With reference to FIGS. 10-12 , through holes 40 ( FIG. 6 ) will now be described. Each hole 40 extends from a top surface 66 of the brush head through a bottom surface 68 . Hole 40 includes first and second portions 70 and 72 . Portion 72 is substantially a parallelepiped except that some of its lower section is rounded off (see FIG. 11 ). Portion 70 is also substantially a parallelepiped except that two of its sides are flared to the sides by about 15 degrees (see FIG. 12 ). Hole portion 72 is longer in a dimension A than hole portion 70 ( FIG. 11 ). Hole portion 70 has about the same width in a dimension B as hole portion 72 where hole portions 70 and 72 meet ( FIG. 12 ). Dimensions A and B are substantially perpendicular to each other in this embodiment. A pair of lips 73 are defined by this arrangement.
[0050] Turning now to FIGS. 13-16 , the insertion of pivoting tufts 30 into holes 40 will be described. A tuft 30 is positioned over a hole 40 with end 62 of anchor pivot 50 facing the hole ( FIG. 13 ). As shown in FIGS. 16 A-C, tuft 30 is moved towards hole 40 until end 62 starts to enter the hole ( FIG. 16A ). Tuft 30 is then pressed into the hole causing sides of hole portion 70 to squeeze second portion 60 of the anchor pivot. Accordingly, anchor pivot 50 collapses causing opening 64 to become temporarily smaller. Tuft 30 is then pushed all the way into hole 40 ( FIG. 16C ) at which point the resilient plastic anchor pivot springs back to its form shown in FIG. 16A . This paragraph describes a snap-fit retention of tuft 30 to the head.
[0051] Referring to FIG. 16C , base support 48 is longer in the A dimension than hole portion 70 and thus prevents tuft 30 from being pressed further into hole 40 . Second portion 60 is also longer in the A dimension than hole portion 70 and so prevents tuft 30 from moving back out of hole 40 . This is due to the fact that lips 63 ( FIG. 8 ) engage lips 73 ( FIG. 11 ). This arrangement also prevents tuft 30 from rotating about the long axis of the bristles.
[0052] As shown in FIG. 15 , tuft 30 pivots when it is engaged by, for example, portions of the oral cavity during brushing. Preferably each tuft 30 can pivot up to about 15 degrees to either side of a position perpendicular to surface 66 .
[0053] Turning to FIGS. 17 and 18 , another type of tooth cleaning element in the form of a fin 80 is disclosed. Each fin is supported by a base support 48 and an anchor pivot 50 (both not shown) as described above, allowing the fin to pivot on the brush head. Alternatively, a fin can be securely affixed to the head so that it does not pivot. The fin is created of a thermoplastic elastomer (TPE) by an injection molding process. In this embodiment, a textured surface is provided by a series of ribs 82 . These ribs enhance cleaning of the oral cavity. The ribs are formed by injection molding a TPE over the fin. The ribs are preferably softer than the fin. Alternative textured surfaces (e.g. dimples) can be used in place of the ribs.
[0054] As shown in FIG. 18 , the fin has a width of preferably about 0.030 inches. The long dimension of the fin above the base support is preferably 0.420 inches. A tip 84 of fin 80 has a width of preferably 0.007 inches. The distance from the base of the ribs to tip 84 is about 0.168 inches whereas the distance from the top of the ribs to the tip is about 0.079 inches. The top of the ribs have a width of about 0.035 inches. The ribs (textured surface) preferably extend about 2-12 mil away from said fin.
[0055] The invention has been described with reference to a preferred embodiment. However, it will be appreciated that variations and modifications can be effected by a person of ordinary skill in the art without departing from the scope of the invention. | A toothbrush has a handle and a head part, on which bristle filaments and at least one flexible cleaning element are arranged. The at least one flexible cleaning element is arranged on a carrier element which consists of a hard material and is connected to the head part. A process for producing such a toothbrush is also disclosed. | 22,448 |
This application claims priority to provisional U.S. Patent Application Ser. No. 60/489,086 filed on Jul. 22, 2003 entitled “PIPELINE STRUCTURE FOR A SHARED MEMORY PROTOCOL” by Weiss et al.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to processor-based systems, and, more particularly, to providing a higher bandwidth, lower-latency implementation of a scaled shared memory (SSM) protocol.
2. Description of the Related Art
Businesses typically rely on network computing to maintain a competitive advantage over other businesses. As such, developers, when designing processor-based systems for use in network-centric environments, may take several factors into consideration to meet the expectation of the customers, factors such as functionality, reliability, scalability, and performance of such systems.
One example of a processor-based system used in a network-centric environment is a mid-range server system. A single mid-range server system may have a plurality of system boards that may, for example, be configured as one or more domains, where a domain, for example, may act as a separate machine by running its own instance of an operating system to perform one or more of the configured tasks.
A mid-range server, in one embodiment, may employ a distributed shared memory system, where processors from one system board can access memory contents from another system board. The union of all of the memories on the system boards of the mid-range server comprises a distributed shared memory (DSM).
One method of accessing data from other system boards within a system is to broadcast a memory request on a common bus. For example, if a requesting system board desires to access information stored in a memory line residing in a memory of another system board, the requesting system board typically broadcasts on the common bus its memory access request. All of the system boards in the system may receive the same request and the system board whose memory address ranges match the memory address provided in the memory access request may then respond.
The broadcast approach for accessing contents of memories in other system boards may work adequately when a relatively small number of system boards are present in a system. However, such an approach may be unsuitable as the number of system boards grows. As the number of system boards grows, so does the number of memory access requests, thus to handle this increased traffic, larger and faster buses may be needed to allow the memory accesses to complete in a timely manner. Operating a large bus at high speeds may be problematic because of electrical concerns, in part, due to high capacitance, inductance, and the like. Furthermore, a larger number of boards within a system may require extra broadcasts, which could further add undesirable delays and may require additional processing power to handle the extra broadcasts.
Designers have proposed the use of directories in a distributed shared memory system to reduce the need for globally broadcasting memory requests. Typically, each system board serves as a home board for memory lines within a selected memory address range, and where each system board is aware of the memory address ranges belonging to the other system boards within the system. Each home board generally maintains its own directory for memory lines that fall within its address range. Thus, when a requesting board desires to access memory contents from another board, instead of generally broadcasting the memory request in the system, the request is transmitted to the appropriate home board. The home board may consult its directory and determine which system board is capable of responding to the memory request and identify any system boards that need to be informed of the request.
Directories are generally effective in reducing the need for globally broadcasting memory requests during memory accesses. However, implementing a directory that is capable of mapping every memory location within a system board generally represents a significant memory overhead. As such, directory caches are often designed to hold only mappings for a subset of the total memory. The system typically must use some other method, such as broadcasting, to resolve requests for memory that are not currently mapped in the directory cache.
Communication requests between the multiple boards described above (e.g., the requesting board and the home board) generally cause them to develop a client/server relationship. Communications between the multiple boards with client/server relationships may experience an inherent latency of operation during communications between the client and the server. Many times, several system clock cycles may pass during which no significant activity relating to transactions between the client and the server is accomplished. This results in communication latency, which may adversely affect the operation of the server.
Often, latency in communications between the requesting board and the home board may cause several portions of a transaction request to be placed in a queue. An appreciable number of requests may be queued, which may slow the operation of the server. While transaction requests are queued, several system clock cycles may be bypassed due to the latency of communication operations. This may cause a backlog to develop in a queue, which may slow the operation of the server.
The present invention is directed to overcoming, or at least reducing, the effects of, one or more of the problems set forth above.
SUMMARY
In one aspect of the present invention, a method is provided for implementation of a pipeline structure for data transfer. A request is received from a first domain to access a second domain during a first clock cycle. A pipeline structure is used to perform at least a portion of the request during a subsequent clock cycle.
In another aspect of the present invention, a method is provided for implementation of a pipeline structure for data transfer. A request is received from a first domain to access a second domain during a first clock cycle. A determination is made as to whether a latency of operation relating to the request is above a predetermined threshold. A latency reduction process is performed in response to the determination that the latency of operation relating to the request is above a predetermined threshold. The latency reduction process includes using a pipeline protocol to perform at least a portion of the request during a clock cycle substantially immediately following the first clock cycle.
In another aspect of the instant invention, an apparatus is provided for the implementation of a pipeline structure for data transfer. The apparatus of the present invention includes an interface and a first control unit that is communicatively coupled to the interface. The first control unit is adapted to: receive a request from a first domain for data that is storable in a resource associated with a second domain during a first clock cycle; access the data from the resource associated with the second domain using a pipeline structure unit; provide the data to the first domain based upon a pipeline structure provided by the pipeline structure unit; and to provide an indication to the first domain in response to providing the data.
In yet another aspect of the present invention, a computer readable program storage device encoded with instructions is provided for implementation of a pipeline structure for data transfer. A computer readable program storage device encoded with instructions that, when executed by a computer, performs a method, which comprises: receiving a request from a first domain to access a second domain during a first clock cycle; and using a pipeline structure to perform at least a portion of the request during a subsequent clock cycle.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates a block diagram depiction of a system in accordance with one illustrative embodiment of the present invention.
FIG. 2 illustrates a block diagram depiction of an illustrative domain configuration that may be implemented in the system of FIG. 1 , in accordance with one illustrative embodiment of the present invention.
FIG. 3 illustrates a block diagram depiction of a system board set that may be implemented in the system of FIG. 1 , in accordance with one illustrative embodiment of the present invention.
FIGS. 4A , 4 B, and 4 C illustrate a directory cache entry that may be implemented in the system of FIG. 1 , in accordance with one illustrative embodiment of the present invention.
FIG. 5 illustrates a state diagram including the various communication paths between one or more boards of the system of FIG. 1 , in accordance with one illustrative embodiment of the present invention.
FIG. 6 illustrates a flowchart depiction of the method in accordance with one illustrative embodiment of the present invention.
FIG. 7 illustrates a more detailed flowchart depiction of the step of performing a latency reduction process, as indicated in FIG. 6 , in accordance with one illustrative embodiment of the present invention.
FIG. 8 illustrates a more detailed flowchart depiction of the step of performing a request agent protocol, as indicated in FIG. 7 , in accordance with one illustrative embodiment of the present invention.
While the invention is susceptible to various modifications and alternative forms, specific embodiments thereof are shown by way of example in the drawings and will herein be described in detail. It should be understood, however, that the drawings and detailed description thereto are not intended to limit the invention to the particular form disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present invention as defined by the appended claims. Note, the headings are for organizational purposes only and are not meant to be used to limit or interpret the description or claims. Furthermore, note that the word “may” is used throughout this application in a permissive sense (i.e., having the potential to, being able to), not a mandatory sense (i.e., must). The term “include” and derivations thereof mean “including, but not limited to.” The term “connected” means “directly or indirectly connected,” and the term “coupled” means “directly or indirectly coupled.”
DETAILED DESCRIPTION
Embodiments of the present invention provide for improving the bandwidth relating to communications between multiple portions of a server system. The improvements in the bandwidth provided by embodiments of the present invention may be used to reduce the latency of communications between a plurality of portions of the server system. Embodiments of the present invention provide for implementing a pipeline structure such that substantially every clock cycle of a system clock may be used to implement or execute at least a portion of a transaction into the pipeline structure. Embodiments of the present invention provide for reducing the latency of communication systems for improved response to a transaction request made by a portion of a server system.
Turning now to FIG. 1 , a block diagram depiction of a system 10 , in accordance with one illustrative embodiment of the present invention, is provided. The system 10 , in one embodiment, includes a plurality of system control boards 15 ( 1 −2) that are coupled to a switch 20 . For illustrative purposes, lines 21 ( 1 −2) are utilized to show that the system control boards 15 ( 1 −2) are coupled to the switch 20 , although it should be appreciated that, in other embodiments, the boards 15 ( 1 −2) may be coupled to the switch 20 in any of a variety of ways, including by edge connectors, cables, or other available interfaces.
In the illustrated embodiment, the system 10 includes two control boards 15 ( 1 −2), one for managing the overall operation of the system 10 and the other to provide redundancy and automatic failover in the event that the other board fails. Although not so limited, in the illustrated embodiment, the first system control board 15 ( 1 ) serves as a “main” system control board, while the second system control board 15 ( 2 ) serves as an alternate hot-swap replaceable system control board. In one embodiment, during any given moment, generally one of the two system control boards 15 ( 1 −2) actively controls the overall operations of the system 10 .
If failures of the hardware or software occur on the main system control board 15 ( 1 ), or failures on any hardware control path from the main system control board 15 ( 1 ) to other system devices occur, the system controller failover software 22 automatically triggers a failover to the alternative control board 15 ( 2 ). The alternative system control board 15 ( 2 ), in one embodiment, assumes the role of the main system control board 15 ( 1 ) and takes over the responsibilities of the main system control board 15 ( 1 ). To accomplish the transition from the main system control board 15 ( 1 ) to the alternative system control board 15 ( 2 ), it may be desirable to replicate the system controller data, configuration, and/or log files on both of the system control boards 15 ( 1 −2). The system control boards 15 ( 1 −2) in the illustrated embodiment may each include a respective control unit 23 ( 1 −2).
The system 10 , in one embodiment, includes a plurality of system board sets 29 ( 1 −n) that are coupled to the switch 20 , as indicated by lines 50 ( 1 −n). The system board sets 29 ( 1 −n) may be coupled to the switch 20 in one of several ways, including edge connectors or other available interfaces. The switch 20 may serve as a communications conduit for the plurality of system board sets 29 ( 1 −n), half of which may be connected on one side of the switch 20 and the other half on the opposite side of the switch 20 .
The switch 20 , in one embodiment, may allow system board sets 29 ( 1 −n) to communicate, if desired. Thus, the switch 20 may allow the two system control boards 15 ( 1 −n) to communicate with each other or with other system board sets 29 ( 1 −n), as well as allow the system board sets 29 ( 1 −n) to communicate with each other.
The system board sets 29 ( 1 −n), in one embodiment, comprise one or more boards, including a system board 30 , I/O board 35 , and expander board 40 . The system board 30 may include processors and associated memories for executing, in one embodiment, applications, including portions of an operating system. The I/O board 35 may manage I/O cards, such as peripheral component interface cards and optical cards that are installed in the system 10 . The expander board 40 , in one embodiment, generally acts as a multiplexer (e.g., 2:1 multiplexer) to allow both the system board 30 and I/O board 35 to interface with the switch 20 , which, in some instances, may have only one slot for interfacing with both boards 30 , 35 .
In one embodiment, the system 10 may be dynamically subdivided into a plurality of system domains, where each domain may have a separate boot disk (to execute a specific instance of the operating system, for example), separate disk storage, network interfaces, and/or I/O interfaces. Each domain, for example, may operate as a separate machine that performs a variety of user-configured services. For example, one or more domains may be designated as an application server, a web server, database server, and the like. In one embodiment, each domain may run its own operating system (e.g., Solaris operating system) and may be reconfigured without interrupting the operation of other domains.
FIG. 2 illustrates an exemplary arrangement where at least two domains are defined in the system 10 . The first domain, identified by vertical cross-sectional lines, includes the system board set 29 (n/ 2 + 2 ), the system board 30 of the system board set 29 ( 1 ), and the I/O board 35 of the system board set 29 ( 2 ). The second domain in the illustrated embodiment includes the system board sets 29 ( 3 ), 29 (n/ 2 + 1 ), and 29 (n/ 2 + 3 ), as well as the I/O board 35 of the system board set 29 ( 1 ) and the system board 30 of the system board set 29 ( 2 ).
As shown, a domain may be formed of an entire system board set 29 ( 1 −n), one or more boards (e.g., system board 30 , I/O board 35 ) from selected system board sets 29 ( 1 −n), or a combination thereof. Although not necessary, it may be possible to define each system board set 29 ( 1 −n) as a separate domain. For example, if each system board set 29 ( 1 −n) were its own domain, the system 10 may conceivably have up to “n” (i.e., the number of system board sets) different domains. When two boards (e.g., system board 30 , I/O board 35 ) from the same system board set 29 ( 1 −n) are in different domains, such a configuration is referred to as a “split expander.” The expander board 40 of the system board sets 29 ( 1 −n), in one embodiment, keeps the transactions separate for each domain. No physical proximity may be needed for boards in a domain.
Using the switch 20 , inter-domain communications may be possible. For example, the switch 20 may provide a high-speed communications path so that data may be exchanged between the first domain and the second domain of FIG. 2 . In one embodiment, a separate path for data and address through the switch 20 may be used for inter-domain communications.
Referring now to FIG. 3 , a block diagram of the system board set 29 ( 1 −n) coupled to the switch 20 is illustrated, in accordance with one embodiment of the present invention. The system board 30 of each system board set 29 ( 1 −n) in the illustrated embodiment includes four processors 360 ( 1 −4), with each of the processors 360 ( 1 −4) having an associated memory 361 ( 1 −4). In one embodiment, each of the processors 360 ( 1 −4) may be coupled to a respective cache memory 362 ( 1 −4). In other embodiments, each of the processors 360 ( 1 −4) may have more than one associated cache memories 362 ( 1 −4), wherein some or all of the one or more cache memories 362 ( 1 −4) may reside within the processors 360 ( 1 −4). In one embodiment, each cache memory 362 ( 1 −4) may be a split cache, where a storage portion of the cache memory 362 ( 1 −4) may be external to the processor, and a control portion (e.g., tags and flags) may be resident inside the processors 360 ( 1 −4).
The processors 360 ( 1 −4), in one embodiment, may be able to access their own respective memories 361 ( 1 −4) and cache memories 362 ( 1 −4), as well as access the memories associated with other processors. In one embodiment, a different number of processors and memories may be employed in any desirable combination, depending on the implementation. In one embodiment, two five-port dual data switches 365 ( 1 −2) connect the processor/memory pairs (e.g., processors 360 ( 1 −2)/memories 361 ( 1 −2) and processors 360 ( 3 −4)/memories 361 ( 3 −4)) to a board data switch 367 .
Although not so limited, the I/O board 35 of each system board set 29 ( 1 −n) in the illustrated embodiment includes a controller 370 for managing one or more of the PCI cards that may be installed in one or more PCI slots 372 ( 1 −p). In the illustrated embodiment, the I/O board 35 also includes a second controller 374 for managing one or more I/O cards that may be installed in one or more I/O slots 376 ( 1 −o). The I/O slots 376 ( 1 −o) may receive optic cards, network cards, and the like. The I/O board 35 , in one embodiment, may communicate with the system control board 15 ( 1 −2) (see FIG. 1 ) over an internal network (not shown).
The two controllers 370 , 374 of the I/O board 35 , in one embodiment, are coupled to a data switch 378 . A switch 380 in the expander board 40 receives the output signal from the data switch 378 of the I/O board 35 and from the switch 367 of the system board set 29 ( 1 −n) and provides it to a System Data Interface (SDI) 383 , in one embodiment. The SDI 383 may process data transactions to and from the switch 20 and the system board 30 and I/O board 35 . A separate address path (shown in dashed lines) is shown from the processors 360 ( 1 −4) and the controllers 370 , 374 to the coherency module 382 . In the illustrated embodiment, the SDI 383 includes a buffer 384 , described in more detail below. The coherency module 382 may process address and response transactions to and from the switch 20 and the system and I/O boards 30 and 35 .
In one embodiment, the switch 20 may include a data switch 385 , address switch 386 , and response switch 388 for transmitting respective data, address, and control signals provided by the coherency module 382 or SDI 383 of each expander board 40 of the system board sets 29 ( 1 −n). Thus, in one embodiment, the switch 20 may include three 18×18 crossbar switches that provide a separate data path, address path, and control signal path to allow intra- and inter-domain communications. Using separate paths for data, addresses, and control signals, may reduce the interference among data traffic, address traffic, and control signal traffic. In one embodiment, the switch 20 may provide a bandwidth of about 43 Gigabytes per second. In other embodiments, a higher or lower bandwidth may be achieved using the switch 20 .
It should be noted that the arrangement and/or location of various components (e.g., coherency module 382 , processors 360 ( 1 −4), controllers 370 , 374 ) within each system board set 29 ( 1 −4) is a matter of design choice, and thus may vary from one implementation to another. Additionally, more or fewer components may be employed without deviating from the scope of the present invention.
In accordance with one embodiment of the present invention, cache coherency is performed at two different levels, one at the intra-system board set 29 ( 1 −n) level and one at the inter-system board set 29 ( 1 −n) level. With respect to the first level, cache coherency within each system board set 29 ( 1 −n) is performed, in one embodiment, using conventional cache coherency snooping techniques, such as the modified, owned, exclusive, shared, and invalid (MOESI) cache coherency protocol. Memory lines transition into the 0 state from M if another processor 360 ( 1 −4) requests a shared copy. A line in the 0 state cannot be modified, and is written back to memory when victimized. It represents a shared line for which the data in memory is out of date. The processors 360 ( 1 −4) may broadcast transactions to other devices within the system board set 29 ( 1 −n), where the appropriate device(s) may then respond with the desired results or data.
Because the number of devices within the system board set 29 ( 1 −n) may be relatively small, a conventional coherency snooping technique, in which requests are commonly broadcasted to other devices, may adequately achieve the desired objective. However, because the system 10 may contain a large number of system board sets 29 ( 1 −n), each having one or more processors 360 ( 1 −4), memory accesses may require a large number of broadcasts before such requests can be serviced. Accordingly, a second level of coherency may be performed at the system level (between the expander boards 40 ) by the coherency module 382 of each expander board 40 using, in one embodiment, the scalable shared memory (SSM) protocol.
The coherency module 382 , in one embodiment, includes a control unit 389 coupled to a home agent 390 , a request agent 392 , and a slave agent 394 . Collectively, the agents 390 , 392 , 394 may operate to aid in maintaining system-wide coherency. In the illustrated embodiment, the control unit 389 of the coherency module 382 interconnects the system board 30 and the I/O board 35 as well as interconnects the home agent 390 , request agent 392 , and slave agent 394 within the coherency module 382 . In one embodiment, if the expander board 40 is split between two domains (i.e., the system and the I/O boards 30 and 35 of one system board set 29 ( 1 −n) are in different domains), the control unit 389 of the coherency module 382 may arbitrate the system board 30 and I/O board 35 separately, one on odd cycles and the other on even cycles.
The coherency module 382 may also include a pipeline structure unit 393 that is capable of providing a pipeline structure for executing transactions requested by various portions of the system 10 . Tasks handled by the request agent 392 and/or the home agent 390 may be positioned in a pipeline format by the pipeline structure unit 393 . In one embodiment, on substantially every system clock cycle, a new transaction is moved into the pipeline provided by the pipeline structure unit 393 such that a portion of a requested transaction is performed on each system clock cycle. Performing a portion of a transaction on substantially every system clock cycle increases the bandwidth of the SSM protocol. A more detailed description of increasing the bandwidth of the SSM protocol is provided below. The pipeline structure unit 393 may be a software, hardware, or firmware unit that is a standalone unit or may be integrated into a control unit 389 . The pipeline structure unit 393 may be implemented into various portions of the system 10 , including the expander board 40 , the system board 30 , and/or the I/O board 35 .
The SSM protocol uses MTags embedded in the data to control what the devices under the control of each expander board 40 can do to a cache line. The MTags may be stored in the caches 362 ( 1 −4) and/or memories 361 ( 1 −4) of each system board set 29 ( 1 −n). Table 1 below illustrates three types of values that may be associated with MTags.
TABLE 1
MTag Type
Description
Invalid (gI)
No read or write allowed for this type of
line. A device must ask for a new value
before completing an operation with this
line.
Shared (gS)
A read may complete, but not a write.
Modifiable (gM)
Both reads and writes are permitted to this
line.
As mentioned, the Mtag states are employed in the illustrated embodiment in addition to the conventional MOESI cache coherency protocol. For example, to do a write, a device should have a copy of the line that is both M and gM. If the line is gM but not M, then the status of the line may be promoted to M with a transaction within the expander board 40 . If the line is not gM, then a remote transaction may have to be done involving the cache coherency module 382 , which, as mentioned, employs the SSM protocol in one embodiment.
The coherency module 382 , in one embodiment, controls a directory cache (DC) 396 that holds information about lines of memory that have been recently referenced using the SSM protocol. The DC 396 , in one embodiment, may be stored in a volatile memory, such as a static random access memory (SRAM). The DC 396 may be a partial directory in that it may not have enough entry slots to hold all of the cacheable lines that are associated with a given expander board 40 . As is described in more detail later, the coherency module 382 , in one embodiment, controls a locking module 398 that prevents access to a selected entry in the directory cache 396 when the status of that entry, for example, is being updated.
The DC 396 may be capable of caching a predefined number of directory entries corresponding to cache lines of the caches 362 ( 1 −4) for a given system board 30 . The DC 396 may be chosen to be of a suitable size so that a reasonable number of commonly used memory blocks may generally be cached. Although not so limited, in the illustrated embodiment, the DC 396 is a 3-way set-associative cache, formed of three SRAMs that can be read in parallel. An exemplary 3-wide DC entry is shown in FIG. 4A . The DC 396 , in one embodiment, includes 3-wide DC entries (collectively referred to as a “set”) 410 . Each DC entry in a given set 410 may be indexed by a partial address.
As shown in FIG. 4A , in one embodiment, each of the three DC entry fields 415 ( 0 −2) has an associated address parity field 420 ( 0 −2). Each set 410 includes an error correction code (ECC) field 425 ( 0 −1). In case of errors, the ECC field 425 ( 0 −1) may allow error correction, in some instances. Each 3-wide DC entry in a given set 410 includes a least recently modified (LRM) field 430 that may identify which of the three DC entry fields 415 ( 0 −2) was least recently modified. Although other encoding techniques may be employed, in the illustrated embodiment, three bits are used to identify the LRM entry. An exemplary list of LRM codes employed in the illustrated embodiment is provided in Table 2 below.
TABLE 2
DC Least-Recently-Modified encoding
LRM
Most Recent
Middle
Least Recent
000
Entry 0
Entry 1
Entry 2
001
Entry 1
Entry 0
Entry 2
010
Entry 2
Entry 0
Entry 1
011
***undefined state ***
100
Entry 0
Entry 2
Entry 1
101
Entry 1
Entry 2
Entry 0
110
Entry 2
Entry 1
Entry 0
111
*** undefined state ***
As indicated in the exemplary LRM encoding scheme of Table 2, various combinations of bits in the LRM field 430 identify the order in which the three entry fields 415 ( 0 −2) in the DC 396 were modified. As an example, the digits ‘000’ (i.e., the first entry in Table 2), indicate that the entry field 415 ( 2 ) was least recently modified, followed by the middle entry field 415 ( 1 ), and then the first entry field 415 ( 0 ), which was most recently modified. As an added example, the digits ‘101’ indicate that the entry field 415 ( 0 ) was least recently modified, followed by the entry field 415 ( 2 ), and then the entry field 415 ( 1 ), which was most recently modified. As described later, the LRM field 430 , in one embodiment, is utilized, in part, to determine which DC entry field 415 ( 0 −2) to victimize from a particular set 410 of the DC 396 when that set 410 is full.
In accordance with one embodiment of the present invention, two different types of entries, a shared entry 435 and an owned entry 437 , may be stored in the entry fields 415 ( 0 −2) of the DC 396 , as shown in FIGS. 4B-C . An owned entry 437 , in one embodiment, signifies expander board 40 has both read and write access for that particular entry. A shared entry 435 , in one embodiment, indicates that one or more expander boards 40 have read, but not write, access for that particular entry.
The shared entry 435 , in one embodiment, includes an identifier field 440 , a mask field 445 , and an address tag field 450 . The identifier field 440 , in the illustrated embodiment, is a single bit field, which, if equal to bit 1 , indicates that the stored cache line is shared by one or more of the processors 360 ( 1 −4) of the system board sets 29 ( 1 −n) in the system 10 . The mask field 445 , which may have up to “n” bits (i.e., one bit for each of the system board sets 29 ( 1 −n)), identifies through a series of bits which of the system boards 30 of the system board sets 29 ( 1 −n), has a shared copy of the cache line. The address tag field 450 may store at least a portion of the address field of the corresponding cache line, in one embodiment.
The owned entry 437 includes an identifier field 455 , an owner field 460 , an address tag field 465 , a valid field 470 , and a retention bit field 475 , in one embodiment. The identifier field 455 , in the illustrated embodiment, is a single bit field, which, if equal to bit 0 , indicates that the stored cache line is owned by the named expander in the system 10 . The owner field 460 is adapted to store the identity of a particular expander board 40 of the system board sets 29 ( 1 −n) that holds the valid copy of the cache line. The address tag field 465 may be adapted to store at least an identifying portion of the address field of the corresponding cache line, in one embodiment. For example, the tag field 465 may be comprised of the upper order bits of the address. The valid field 470 , in one embodiment, indicates if the corresponding entry in the DC 396 is valid. An entry in the DC 396 may be invalid at start-up, for example, when the system 10 or domain in the system 10 is first initialized. If the invalid bit is “0,” an actual ownership of a line by a named expander is recorded in the owner field 460 .
Referring now to FIG. 5 , a state diagram including the various communication paths between a requesting board 510 , a home board 520 , and slave board 530 in servicing memory access requests is illustrated, in accordance with one or more embodiments of the present invention. The boards 510 , 520 , 530 , in one embodiment, may include one or more boards (e.g., expander board 40 , system board 30 , I/O board 35 ) of one or more control board sets 29 ( 1 −n). The term “memory access requests,” as utilized herein, may include, in one embodiment, one or more of the processors 360 ( 1 −4) (see FIG. 3 ) of a given system board set 29 ( 1 −n) accessing one or more caches 362 ( 1 −4) or memories 361 ( 1 −4) in the system 10 .
Although the invention is not so limited, for the purposes of this discussion, it is herein assumed that one domain is configured in the system 10 that is formed of one or more complete (i.e., no split expanders) system board sets 29 ( 1 −n). Generally, a given cache line in the system 10 is associated with one home board 520 . The requesting board 510 in the illustrated embodiment represents a board attempting to access a selected cache line. The slave board 530 in the illustrated embodiment represents a board that currently has a copy of a cache line that the requesting board 510 is attempting to access. In a case where a current copy of a requested cache line resides in the home board 520 , then the home board 520 is also the slave board 530 for that transaction.
The requesting board 510 may initiate one of a variety of memory access transactions, including request-to-own (RTO), request-to-share (RTS), WriteStream, WriteBack, and ReadStream transactions. One or more of the aforementioned memory access transactions may be local or remote transactions, where local transactions may include transactions that are broadcast locally within the system board set 29 ( 1 −n) and remote transactions may include transactions that are intended to access cache lines from other system board sets 29 ( 1 −n). Although not so limited, in one embodiment, an RTO may be issued to obtain an exclusive copy of a cache line, an RTS to obtain a shared copy of a cache line, a WriteBack transaction to write the cached line back to the home board, a ReadStream request to get a snapshot copy of the cache line, and a WriteStream request to write a copy of the cache line.
For illustrative purposes, an exemplary RTO transaction among the boards 510 , 520 , and 530 is described below. For the purpose of this illustration, it is herein assumed that the requesting board 510 is attempting to obtain write-access to a cache line owned by the home board 520 , where the latest copy of the requested cache line resides on the slave board 530 . The RTO from the requesting board 510 is forwarded to the home board 520 via path 540 . Forwarding of the RTO from the requesting board 510 to the home board 520 is typically handled by the coherency module 382 (see FIG. 3 ) of the requesting board 510 utilizing the address provided with the RTO.
The requesting board 510 determines which of the home boards 520 has the requested cache line by, for example, mapping the address of the cache line to the address ranges of the caches associated with the various expander boards 40 within the system 10 . When the home board 520 receives the RTO message over the path 540 , the coherency module 382 of the home board 520 checks its directory cache 396 (see FIG. 3 ) to determine if there is an entry corresponding to the requested cache line. Assuming that an entry exists in the directory cache 396 , the home board 520 may reference the information stored in that entry to determine if the slave board 530 currently has an exclusive copy of the requested cache line. It should be noted, in one embodiment, that while the directory cache 396 of the home board 520 is being referenced, the coherency module 382 may use the locking module 398 to at least temporarily prevent other expander boards 40 from accessing that entry in the directory cache 396 .
Based on the information stored in the directory cache 396 , the home board 520 is able to ascertain, in one embodiment, that the slave board 530 currently has an exclusive copy of the cache line. Accordingly, the home board 520 , in one embodiment, transmits a request over a path 545 to the slave board 530 to forward a copy of the requested cache line to the requesting board 510 . In one embodiment, the slave board 530 downgrades its copy from an exclusive copy (i.e., M-type) to an invalid copy (i.e., I-type) since, by definition, if one board in the system 10 has an exclusive M-copy (i.e., the requesting board 510 in this case), all other nodes should have invalid I-copies.
When the requesting board 510 receives a copy of the cache line over a path 550 , it internally notes that it now has an exclusive M-copy and acknowledges over a path 555 . When the home board 520 receives the acknowledgment message from the requesting board 510 over the path 555 , the home board 520 updates its directory cache 396 to reflect that the requesting board 510 now has write-access to the cache line, and may use the locking module 398 to allow other transactions involving the cache line to be serviced. The paths 540 , 545 , 550 , and 555 , in one embodiment, may be paths through the switch 20 (see FIGS. 1 and 3 ).
As other transactions occur for accessing cache lines in the home board 520 , for example, the coherency module 382 of the home board 520 routinely may update its directory cache 396 to reflect the status of the referenced cache lines. The status of the referenced cache lines may include information regarding the state of the cache line (e.g., M, I, S), ownership rights, and the like. At any given time, because of the finite size of the directory cache 396 , it may be possible that a particular set 410 within the directory cache 396 may be full. When a particular set 410 within the directory cache 396 is full, it may be desirable to discard or overwrite old entries to store new entries since it may be desirable to retain some entries in the directory cache 396 over others.
Embodiments of the present invention provide for servicing at least a portion of a transaction between the requesting boards 510 , the home board 520 , and/or the slave board 530 in response to virtually every clock cycle.
Turning now to FIG. 6 , a flow chart depiction of the methods in accordance with one illustrative embodiment of the present invention is provided. The system 10 provides for developing a client/server relationship between the requesting board 510 and the home board 520 and/or the slave board 530 for executing transactions, such as memory transactions (block 610 ). For example, the requesting board 510 may initiate a memory access transaction and a write back transaction to write the cache line back to the home board 520 . The transaction may be queued in response to a determination that the home agent 390 in the coherency module 382 is not prepared to execute the requested transaction.
The system 10 may then determine a latency of operation related to the communications between the client/server described above (block 620 ). The system 10 may calculate or determine that the latency may be above a predetermined threshold (block 630 ). The latency threshold may depend upon a predetermined acceptable latency set by the system 10 . When the system 10 determines that the latency is at or below the predetermined threshold, normal communication described above is continued (block 640 ). However, when the system 10 determines that the latency is above the predetermined threshold, a latency reduction process in response to the latency is implemented by the system 10 (block 650 ).
Embodiments of the present invention provide for implementing a high-bandwidth, low-latency communications protocol. For example, pipeline structures may be set-up such that during virtually every clock cycle, a new transaction may be moved into position into the pipeline structure described above, to perform the requested portion of the transaction function. In one embodiment, the pipeline structure unit 393 is used by the system 10 to utilize substantially every clock cycle to perform at least a portion of the requested transaction. A more detailed description and illustration of the latency reduction process indicated in block 650 of FIG. 6 , is provided in FIG. 7 .
Turning now to FIG. 7 , a flowchart depiction of the methods for performing a client/server transaction in accordance with an illustrative embodiment of the present invention is provided. When the system 10 receives a request for a transaction, such as a memory transaction, a request agent protocol is performed (block 710 ). The request agent protocol involves searching for a transaction to be handled by the SSM protocol. A more detailed description of the request agent protocol is provided in FIG. 8 and accompanying description below.
Upon performing the request agent protocol, the system 10 determines if the target home agent 390 of one of the boards 510 , 520 , 530 is ready to execute the request (block 720 , 730 ). If the target home agent 390 is not ready to execute the requested transaction, the transaction is placed into a queue (block 740 ). The requested transaction is removed from the queue when the target home agent 390 is ready to execute the transaction. When the home agent 390 is ready to execute the transaction request, the system 10 performs a lock transaction (block 750 ). In one embodiment, the system 10 may use the locking module 398 to prevent other entities in the system 10 from accessing a particular entry in the directory cache 396 of the target home board 520 .
The system 10 then compares the transaction that is requested to currently outstanding transactions (block 760 ). A record of transactions that indicates currently outstanding transactions is used to compare the current requested transaction to see if its address matches with a transaction that is already being handled by the system 10 . Even if an exhaustive transaction list is not available for all addresses, a selected number of transactions may be recorded, such that a rapid determination may be made, whether a particular requested transaction is to be handled (block 770 ).
Generally, an efficient transaction list may be used to compare the requested transaction within one clock cycle to make a fast determination whether a particular transaction is to be handled. The pipeline structure described above may be used to move each new transaction into a position in the pipeline, such that during virtually every clock cycle, a portion of the requested transaction is executed. Within a clock cycle of encountering the transaction, the system 10 may determine that there is an address match resulting from the transaction comparison. The matched address may then be sent to a local device and to the local coherency module 382 , which may look up the address in the coherence directory cache (block 780 ). The system 10 then prepares to execute the requested transaction. The target home agent 390 and any slave agents 394 may then execute at least a portion of the transaction (block 790 ).
The home agent 390 and any slave agents 394 may then send responses to the request agent 392 that it looks up the nature of the transaction that is being referred to and completes the transaction to the requesting processor or I/O device, and then sends a further response back to the home agent 390 to have it unlock the transaction when the unlocking of the transaction is appropriate. For example, in order to read data from memory, the interchange between the home agent 390 , the slave agent 394 , and the requesting request agent 392 operates such that rather than having the home agent 390 maintain this transaction in a wait state, embodiments of the present invention provide for a protocol engine (e.g., the pipeline structure unit 393 ) that sends the transaction to a queuing structure. The requested transaction is then recycled back to the protocol engine at a later time, where there is a further step to be accomplished in the protocol. Meanwhile, on every intervening clock cycle, another transaction may be passed through the protocol cycle such that all clock cycles are utilized to move a requested transaction forward. Therefore, the bandwidth of the SSM protocol is increased and more efficient transactions in the system 10 may take place.
Turning now to FIG. 8 , a block diagram depiction of the step of performing the request agent protocol indicated in block 710 of FIG. 7 is illustrated. The system 10 may look for transactions to be handled by the SSM protocol based upon a requested transaction (block 810 ). This function may be performed by the request agent 392 . The transaction is then acquired from a bus that interconnects the various components of the system 10 (block 820 ). Information regarding the transaction may then be recorded for later comparison with other requested transactions (block 830 ). The transaction is then sent to an appropriate home agent 390 for processing (block 840 ).
The requested transaction may be sent to the switch 20 , which comprises a centerplane, such that the data regarding the transaction goes through the centerplane and then drives another coherency module 382 , but at the home agent 390 . At that position, it is queued up to determine whether the home agent 390 is ready to execute the transaction. A pipeline structure 393 is used such that for virtually every clock cycle a new transaction moves into each position of the pipeline to perform a portion of the requested transaction function, therefore it may be queued such that it may be recycled back to the protocol cycle at a later time. During this time, other intervening clock cycles are used to perform other transactions that are passed through the protocol cycle. Completion of the steps described in FIG. 8 substantially completes the process of performing the request agent protocol indicated in block 710 of FIG. 7 .
For ease of illustration, several references to “cache line(s)” or “line(s)” are made in the discussion herein with respect to memory access. It should be appreciated that these references, as utilized in this discussion, may refer to any line that is cacheable, and include one or more bits of information that is retrieved from the caches 362 ( 1 −4) and/or memories 361 ( 1 −4) (see FIG. 3 ) in the system 10 .
The various system layers, routines, or modules may be executable control units (such as control unit 389 (see FIG. 3 ). Each control unit 389 may include a microprocessor, a microcontroller, a digital signal processor, a processor card (including one or more microprocessors or controllers), or other control or computing devices.
The storage devices referred to in this discussion may include one or more machine-readable storage media for storing data and instructions. The storage media may include different forms of memory including semiconductor memory devices such as dynamic or static random access memories (DRAMs or SRAMs), erasable and programmable read-only memories (EPROMs), electrically erasable and programmable read-only memories (EEPROMs) and flash memories; magnetic disks such as fixed, floppy, removable disks; other magnetic media including tape; and optical media such as compact disks (CDs) or digital video disks (DVDs). Instructions that make up the various software layers, routines, or modules in the various systems may be stored in respective storage devices. The instructions when executed by a respective control unit cause the corresponding system to perform programmed acts.
Although the embodiments above have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications. | A method and apparatus for implementation of a pipeline structure for data transfer. A request is received from a first domain to access a second domain during a first clock cycle. A pipeline structure is used to perform at least a portion of the request during a subsequent clock cycle. | 51,934 |
BACKGROUND
[0001] Sealing devices are well known in the hydrocarbon recovery industry due to their ubiquitous use pursuant to varied needs throughout the wellbore. There are also many different types of sealing devices, some of which allow for testing immediately after setting by pressuring up on the well system to ensure that the setting procedure was successful. This is clearly beneficial as there is an immediate confirmation of a successful job. This occurs before the operator leaves the job site to insure that the job went well and thus promotes customer satisfaction.
[0002] While the above testing opportunity is the case for many kinds of sealing devices it is not so for all devices. Swellable devices cannot be tested because their initial actuation is a much longer-term program. More specifically, swellable materials that are used in the wellbore generally set over a time period of about two weeks. While setting time does vary (due to particular fluid concentration and chemistry and the temperature of the wellbore at the location of the set), it is always over time long enough that it would be decidedly uneconomical to maintain testing equipment at a site to test such a seal after it is expected to be fully set.
[0003] Because swellable materials have other beneficial properties and are favored in the art, they are becoming more and more prevalent despite the fact that testing is not realistically plausible.
SUMMARY
[0004] A swellable setting confirmation arrangement comprising a mandrel; a swellable material supported by the mandrel; one or more sensory configurations at the swellable material.
[0005] A method for confirming setting of a swellable material comprising: running a swellable material to a target location in a wellbore; swelling the swellable material for a period of time; measuring strain caused by the swelling of the swellable material with one or more sensory configurations.
[0006] A method for installing a swellable material having a setting confirmation function in a wellbore comprising: Installing one or more sensory configurations in a wellbore; installing a swellable material radially adjacent the one or more sensory configurations.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] Referring now to the drawings wherein like elements are numbered alike in the several Figures:
[0008] FIG. 1 is a schematic view of a first embodiment of a set verification arrangement for a swellable device;
[0009] FIG. 1A is an alternate configuration showing the sensory configuration in a spaced helical pattern;
[0010] FIG. 1B is an alternate configuration showing the sensory configuration in a non-spaced helical pattern;
[0011] FIG. 2 is a schematic view of a second embodiment of a set verification arrangement for a swellable device;
[0012] FIG. 3 is a schematic view of a third embodiment of a set verification arrangement for a swellable device; and
[0013] FIG. 4 is a schematic view of a fourth embodiment of a set verification arrangement for a swellable device.
DETAILED DESCRIPTION
[0014] The above-described drawback to the use of swellable devices in the downhole environment is overcome through various embodiments and methods as disclosed herein.
[0015] Referring to FIG. 1 , a first embodiment is illustrated schematically in quarter section. A swellable setting confirmation arrangement 10 comprises a mandrel 12 having a swellable material 14 disposed there around. In one iteration, the swellable material 14 is around the mandrel 12 for 360 degrees but it should be noted that it is not necessarily required that the swellable material 14 be so configured. It is possible in other embodiments for the material 14 to be something short of 360 degrees about the mandrel 12 for particular applications without effect on the arrangement disclosed herein. Between the mandrel 12 and the swellable material 14 is disposed one or more sensory configuration(s) 16 . The configuration may comprise one or more optic fibers, load cells, strain sensors, such as hall effect sensors, momentary switches, etc. that have the ability to sense a load placed thereon (on or off, a “dichotomous measurement”). In one embodiment, the sensor(s) not only sense the presence of a load but additionally quantifies that load as well. The foregoing sensory configurations can be configured to sense quantitatively by known methods. Such sensing includes but are not limited to mercury strain gauges, rubber strain gauges, piezo resistance strain gauges, silicon strain gauges, wheatstone bridges, intrinsic sensors, extrinsic sensors, electro mechanical sensors, electro optic sensors, etc. An optic fiber based sensory configuration is an example of a configuration capable of both. The one or more sensory configurations 16 may thus be a single optic fiber, a plurality of fibers, a bundle of fibers, etc. extending roughly longitudinally and generally parallel to the mandrel 12 , or extending helically about the mandrel 12 (with the helix ranging from tightly wrapped (see FIG. 1B ) such that there is no gap between adjacent wraps of the optic fiber(s) to loosely wrapped (see FIG. 1 A) so that gaps from small to large may exist between the adjacent wraps of optic fiber(s)depending upon resolution desired). Determination of the density of the sensory configuration is directly related to the resolution of the information desired to be obtained. The greater the resolution desired, the greater the density needed. It is to be understood that the helical illustration of FIG. 1 is equally applicable to the FIG. 2 and FIG. 3 embodiments by substituting the configuration 16 in those illustrations for the configurations 16 shown in FIGS. 1A and 1B . It is intended that the reader understand that the helical conditions shown are applicable to any of the embodiments of the invention.
[0016] In other embodiments, the one or more sensory configurations 16 may be placed randomly between the swellable material 14 and mandrel 12 or may be placed in any desired pattern between material 14 and mandrel 12 . This includes a pattern that is affected by the use of a network of strain sensors in a net of electrical connection, etc. The pattern may itself be unrelated to any anticipated distribution of strain (in which case the distribution is likely to be uniform but is not required to be) or may be specifically placed with regard to anticipated strain distribution. In either case, the purpose of the one or more sensory configurations 16 is to sense strain placed thereon by the swelling of the swellable material 14 .
[0017] When a swellable material is set in a wellbore the material 14 will exert pressure against the mandrel 12 and the structure against which it is set. Depending upon a number of factors including but not limited to the degree of swelling attained and the geometric shape of the structure in which the swellable device is being set, the strain experienced at various portions of the swellable material and thus the mandrel may be different. The swellable setting confirmation arrangement 10 provides information to this effect to an operator. As noted above, since the swellable material swells slowly in the wellbore, on the order of two weeks, there is no way to test the set of the swellable while the installation crew and equipment is still on site. This means that if the swellable did not attain a set that enables it to do its job, this will not necessarily be known and presumably, production will suffer. If a well operator knows that something was a miss, remedial action could be taken. Where the arrangement 10 merely shows existence or absence of strain enough information is provided that the operator knows the device must be pulled and a new one put in. Where however, the arrangement 10 also provides a quantification of the strain thereon, a much more resolute picture of the downhole environment can be gleaned. This enables an operator or swellable installation crew to determine more precisely what type, shape, style, etc. of swellable would be best suited to have the desired effect in the particular wellbore. This is possible because with a quantification of strain, the geometry in the wellbore is far better defined since areas of greater strain and areas of lesser strain will indicate washed out areas or out of round areas of the structure downhole in which the device is being set.
[0018] In the embodiments discussed above, as the swellable material swells into contact with a structure in which it is being set, the material 14 itself exerts more and more pressure on the mandrel. Because the one or more sensory configurations 16 are located between the material 14 and the mandrel 12 , they are compressed there between and hence will register that condition either dichotomously or quantitatively depending upon application.
[0019] In another embodiment illustrated in FIG. 2 , the one or more sensory configurations 16 are embedded in the swellable material 14 . The one or more sensory configurations are hence put into compression upon swelling of the swellable material 14 similarly to that of the embodiment of FIG. 1 but the compression profile is distinct in that the configurations 16 are not directly compressed against the mandrel 12 . While the magnitude of compression may be smaller in this embodiment, it is still easily measured dichotomously or quantitatively. Further, in this embodiment the one or more sensory configurations may be better environmentally protected for some applications.
[0020] In yet another embodiment, referring to FIG. 3 , the one or more sensory configurations 16 are located on an outside surface 20 of the material 14 . In this embodiment, the configurations 16 are exposed to the wellbore and are more likely to experience damage but they also will be directly in contact with the surface against which the swellable material 14 is to be set. This will provide a very accurate indication of the surface irregularities of the structure in applications where such is useful.
[0021] In yet another embodiment, referring to FIG. 4 , the one or more sensory configurations 16 (each of those disclosed above are possible) are separated from the swellable material 14 . In one iteration the separated sensory configurations are still mounted to the same mandrel so that they can be put in place in a single run whereas in another iteration, the sensory configurations 16 could be mounted to a separate string for run in separately from the swellable material 14 if dictated by a particular need. FIG. 4 schematically illustrates both concepts by including a break line 26 that is intended to signify alternatively length of the mandrel 12 or a separate mandrel run at a different time. In either of these iterations, the one or more sensory configurations 16 are mountable in the wellbore 22 via a deployment method such as expansion. One embodiment will use rings 28 and 30 on either end of the configurations 16 that are expandable and will anchor the configurations 16 to the wellbore 22 . The configurations 16 are thus affixed to the wellbore 22 where after the swellable material 14 is positioned inside of the configuration(s) 16 and allowed to swell in the normal course. Progress of the swellable material can be monitored, as can that of the foregoing embodiments through the one or more sensory configurations 16 . It is also to be noted that the components can be reversed such that the configurations 16 are placed at a radially inward position instead of outward with similar effects.
[0022] While preferred embodiments have been shown and described, modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation | A swellable setting confirmation arrangement comprising: a mandrel; a swellable material supported by the mandrel; one or more sensory configurations at the swellable material and a method for confirming setting of a swellable material and for installing a swellable material having a setting confirmation function. | 12,345 |
GOVERNMENT SUPPORT
Experimental work described herein was supported by grants from the United States Government which may have certain rights in the invention.
BACKGROUND OF THE INVENTION
Transmembrane receptors are proteins which are localized in the plasma membrane of eukaryotic cells. These receptors have an extracellular domain, a transmembrane domain and an intracellular domain. Transmembrane receptors mediate molecular signaling functions by, for example, binding specifically with an external signaling molecule (referred to as a ligand) which activates the receptor. Activation results typically in the triggering of an intracellular catalytic function which is carried out by, or mediated through, the intracellular domain of the transmembrane receptor.
There are various families of transmembrane receptors that show overall similarity in sequence. The highest conservation of sequence is in the intracellular catalytic domain. Characteristic amino acid position can be used to define classes of receptors or to distinguish related family members. Sequences are much more divergent in the extracellular domain.
A variety of methods have been developed for the identification and isolation of transmembrane receptors. This is frequently a straightforward matter since receptors often share a common sequence in their catalytic domain. However, the identification of the ligands which bind to, and activate, the transmembrane receptors is a much more difficult undertaking. Brute force approaches for the identification of ligands for known receptors are rarely successful. Brute force approaches usually depend on a biological activity that can be monitored (e.g., nerve growth for nerve growth factor; or glucose homeostasis for the insulin receptor) or they depend on finding a source of the ligand and using affinity to purify it (as was used to find the c-Kit ligand in mouse hemopoietic cells). In general, however, a source of the ligand is not known, nor is there an obvious or easily assayable biological activity. Therefore, there are many receptors, referred to as "orphan receptors" for which no corresponding ligand has been identified. A systematic approach to the identification of receptor ligands would be of great value for the identification of ligands having useful pharmacological activities.
SUMMARY OF THE INVENTION
The present invention relates to compositions and methods which are useful in connection with the identification of transmembrane receptors and their corresponding ligands. Preferred transmembrane receptors include tyrosine kinase receptors, cytokine receptors and tyrosine phosphatase receptors. Such receptors mediate cell signaling through the interaction of specific binding pairs (e.g., receptor/ligand pairs). The present invention is based on the finding that an unknown component in a receptor-mediated signaling pathway, which results ultimately in an intracellular catalytic event, can be identified by combining other known components within a cellular background within which the catalytic event ordinarily will not take place at significant levels. A cDNA expression library is then used to transform such cells. If the cDNA insert encodes the missing component of the transmembrane receptor-mediated signaling pathway, the catalytic event will be triggered. Detection of the otherwise absent catalytic activity is indicative of a cDNA insert encoding the missing component.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram illustrating the steps employed in the identification of a ligand specific for the FGF receptor.
FIG. 2 is a diagram illustrating the colony Western blot technique.
DETAILED DESCRIPTION OF THE INVENTION
Transmembrane receptors have a binding site with high affinity for a specific signaling molecule. The signaling molecule is referred to herein as a ligand. The present invention is based on the development of a novel approach for the identification of polypeptide ligands by functional expression in the yeast Saccharomyces cerevisiae. This approach is based on the previously unproven hypothesis that it may be possible to functionally express a heterologous tyrosine kinase receptor and its corresponding polypeptide ligand in the same yeast cell, leading to the activation of the receptor and a substantial increase in intracellular tyrosine phosphorylation. The intracellular tyrosine kinase activity of the tyrosine kinase receptor is activated by the binding of a ligand to the extracellular domain of the receptor. This interaction can occur on the surface of the cell (plasma membrane) or in intracellular membrane compartments such as secretory vesicles. In either case, according to the hypothesis confirmed herein, the activation of the cytoplasmically oriented kinase domain results in phosphorylation of tyrosine residues of cytoplasmic protein targets.
Yeast was chosen as an expression system because many molecular biological techniques are available and it has been demonstrated that many higher eukaryotic genes, including some growth factor-encoding genes, can be functionally expressed in yeast. In addition, only a few endogenous protein tyrosine kinases have been identified in yeast, so that yeast is expected to have a low background of endogenous tyrosine phosphorylation. These features enabled the development of a screen to identify polypeptide ligands for heterologous tyrosine kinase receptors for which no ligand has yet been identified. Such receptors are referred to as orphan receptors. The term heterologous is used herein to mean "non-endogenous". Thus, for example, a tyrosine kinase which is heterologous in the yeast Saccharomyces cerevisiae is a tyrosine kinase which is non-endogenous (i.e., not present) in wild-type Saccharomyces cerevisiae.
The disclosed method for identifying a ligand for a tyrosine kinase receptor involves the co-expression in yeast cells (preferably Saccharomyces cerevisiae) of a gene encoding a tyrosine kinase receptor, together with an expression cDNA library which, for example, is constructed from a tissue or cell line that is thought to synthesize a receptor ligand in vivo. The tyrosine kinase gene, together with any regulatory elements required for expression, can be introduced into the yeast strain on a stable plasmid (e.g., a CEN-based plasmid), or it can be integrated into the yeast chromosome using standard techniques (Methods In Enzymology, vol. 194, C. Guthrie and G. Fink, eds., (1991)).
The choice of expression vectors for use in connection with the cDNA library is not limited to a particular vector. Any expression vector suitable for use in yeast cells is appropriate. The discussion relating to experiments disclosed in the Exemplification section which follows describes a particular combination of elements which was determined to yield meaningful results. However, many options are available for genetic markers, promoters and ancillary expression sequences. As discussed in greater detail below, the use of an inducible promoter to drive expression of the cDNA library is a preferred feature which provides a convenient means for demonstrating that observed changes in tyrosine kinase activity are, in fact, cDNA dependent.
In a preferred format of the assay, two expression constructs are employed; the first expression construct contains the tyrosine kinase gene and the second expression construct carries the cDNA library. Typically the two expression constructs are not introduced simultaneously, but rather a stable yeast strain is first established which harbors the tyrosine kinase receptor carried on a CEN-based plasmid. Other regulatory sequences are included, as needed, to ensure that the tyrosine kinase gene is constitutively expressed. A CEN-based expression vector contains CEN sequences which are specific centromeric regions which promote equal segregation during cell division. The inclusion of such sequences in the expression construct results in improved mitotic segregation. It has been reported, for example, that mitotic segregation of CEN-based plasmids results in a population of cells in which over 90% of the cells carry one to two copies of the CEN-based plasmid. Faulty mitotic segregation in a similar transformation experiment with an otherwise identical expression construct which lacks CEN sequences would be expected to result in a cell population in which only about 5-20% of the cells contain the plasmid.
Many transmembrane tyrosine kinase receptors have been identified (for reviews see, e.g., Hanks, Current Opinion in Structural Biology 1: 369 (1991) and Pawson and Bernstein, Trends in Genetics 6:350 (1990)). A number of these tyrosine kinase receptors are orphan receptors for which no activating ligand has been identified. Any transmembrane tyrosine kinase that can be expressed in yeast cells is useful in connection with the present invention. Based on fundamental principles of molecular biology, there is no reason to believe a priori that any member of the tyrosine kinase receptor family would not be useful in connection with the present invention. Preferably, the gene encoding the tyrosine kinase receptor is isolated from the same organism from which nucleic acid is to be isolated for use in the construction of a cDNA library.
As discussed in the Exemplification section which follows, the level of expression of the transmembrane tyrosine kinase is a variable which must be considered in the design of the assay for ligand identification. For example, it was determined that high level expression of the FGF receptor results in a substantial increase in intracellular phosphorylation, even in the absence of FGF. Therefore, it is important that expression of the transmembrane receptor be driven by regulatory elements which result in a sufficient level of expression of the transmembrane receptor to facilitate detection following activation of the receptor by ligand binding, while not resulting in overexpression to the extent that ligand-independent autophosphorylation results. A preferred promoter for the expression of the transmembrane receptor is the ACT1 (actin) promoter. This promoter was determined to provide a robust, ligand-dependent signal in the experiments described below.
The cDNA library is prepared by conventional techniques. Briefly, mRNA is isolated from an organism of interest. An RNA-directed DNA polymerase is employed for first strand synthesis using the mRNA as template. Second strand synthesis is carried out using a DNA-directed DNA polymerase which results in the cDNA product. Following conventional processing to facilitate cloning of the cDNA, the cDNA is inserted into an expression vector suitable for use in yeast cells. Preferably the promoter which drives expression from the cDNA expression construct is an inducible promoter (e.g., GAL1) .
As disclosed in the Exemplification section that follows, removal of the endogenous signal sequence from a cDNA insert encoding a functional receptor ligand resulted in inactivation of the ligand. It appears, therefore, to be necessary to include a signal sequence in the cDNA library constructs to mark the encoded polypeptide for transport across the membrane of the endoplasmic reticulum thereby enabling the extracellular release of the encoded polypeptide which facilitates interaction with the extracellular domain of a transmembrane receptor. The signal sequence employed in the experiments disclosed herein was the signal sequence of Saccharomyces cerevisiae invertase. However, any signal sequence which can function in yeast should be useful in connection with the present invention (Nothwehr and Gordon, Bioessays 12:479 (1990)).
The cDNA expression library is then used to transform the yeast strain which constitutively expresses the transmembrane tyrosine kinase gene. mRNA encoding the tyrosine kinase receptor and the cDNA product are thought to be translated in the rough endoplasmic reticulum, accumulate in the inner cavity of the rough endoplasmic reticulum, and migrate to the lumen of the Golgi vesicles for transport to the Golgi complex. Within the Golgi complex, proteins are "addressed" for their ultimate destination. From the Golgi complex, the addressed proteins are transported out of the complex by secretory vesicles.
A transmembrane tyrosine kinase receptor, if sequestered in a secretory vesicle, the Golgi complex or the endoplasmic reticulum, is oriented such that the cytoplasmic domain is in contact with the cellular cytoplasm as the various vesicles migrate from the Golgi complex to the plasma membrane which is the ultimate destination for a transmembrane receptor. It is possible that the signal sequence bearing polypeptides encoded by the cDNA library can be co-compartmentalized with the transmembrane receptor in the same secretory vesicle. If this were to occur, any cDNA encoded ligand specific for the tyrosine kinase receptor could bind with the "extracellular" portion of the tyrosine kinase receptor (which is located in the internal portion of the secretory vesicle during the migration to the plasma membrane) thereby activating intracellar tyrosine kinases through contact with the cytoplasmically oriented intracellular domain of the tyrosine kinase receptor.
Alternatively, activation of intracellular tyrosine kinase activity could also result from interaction with an extracellular polypeptide encoded by the cDNA library through interaction with a plasma transmembrane tyrosine kinase receptor. This occurs, for example, following migration of the secretory vesicle to the plasma membrane resulting in the incorporation of the plasma transmembrane tyrosine kinase receptor and export of the signal sequence-bearing cDNA encoded polypeptide ligand.
In either case, activation of the intracellular tyrosine kinase activity results in the phosphorylation of intracellular tyrosine residues at a level which is substantially higher (i.e., at least about 4-fold higher) than background levels of phosphorylation in the yeast stain harboring an expression construct containing only the gene encoding the tyrosine kinase receptor (the negative control strain).
The preferred method for determining the level of intracellular tyrosine phosphorylation is a colony Western blot using replica plates. It will be recognized that, although particularly convenient, the colony Western blot method is but one example of many conventional assays which could be employed to determine levels of intracellular tyrosine kinase activity. The colony Western blot procedure using replica plates is shown diagramatically in FIG. 2. cDNA library transformants are initially plated on media which do not contain an inducer of the promoter which drives expression of the cDNA insert. For examples, if the GAL1 promoter is used to drive expression of the cDNA insert, cDNA library transformants are initially plated on a medium containing 2% glucose. On this growth medium, cells containing the cDNA expression construct will grow, but the encoded cDNA product is not expressed.
A set of replica filters is produced from the initial transformation plate by sequentially placing a set of directionally oriented membranes (e.g., nitrocellulose filter membranes) over the transformation plate such that the membrane contacts existing transformant colonies. Cells from transformation colonies adhere to the membranes to form a pattern which represents the pattern of colonies on the transformation plate. Each of the replica filters is then placed on a separate plate, one of which contains a compound which will induce the inducible promoter (e.g., 2% galactose to induce the GAL1 promoter) and one of which will not induce the inducible promoter (e.g., 2% glucose for the GAL1 promoter). Both plates are incubated overnight to promote regrowth of the original cDNA library transformants.
Following overnight incubation, the replica filters are removed from the growth medium plates, and the colonies are lysed in situ by soaking the replica filters in a lysis solution for a period of time sufficient to lyse cellular membranes (e.g., 0.1% SDS, 0.2 N NaOH, 35 mM DTT for about 30 minutes). The replica filters are then probed with anti-phosphotyrosine antibodies. Colonies which exhibit elevated tyrosine kinase activity on the replica filter which had been incubated overnight on a growth medium containing a compound which induces expression-of the cDNA insert linked to the inducible promoter, but which do not exhibit elevated tyrosine kinase activity on the replica filter incubated overnight on a growth medium lacking the inducing compound, contain a cDNA insert encoding a candidate ligand.
To confirm that a candidate ligand is, in fact, a ligand (and not, for example, a distinct tyrosine kinase), the expression construct is recovered (or rescued) from the cells of the colony demonstrating increased tyrosine kinase activity when grown under inducing conditions. The rescued expression construct is then used to transform a first yeast strain which is known to constitutively express the tyrosine kinase gene, and a second yeast strain which does not express the tyrosine kinase gene. Increased tyrosine kinase activity in the strain which is known to express the tyrosine kinase gene, coupled with no increased tyrosine kinase activity in the strain which does not express the tyrosine kinase gene, serves as confirmation that the cDNA insert of the cDNA expression construct encodes a polypeptide ligand which binds to, and activates, the tyrosine kinase gene product.
Following confirmation that the candidate ligand is, in fact, a receptor ligand, it is a straightforward matter to identify and characterize the polypeptide encoded by the cDNA library which is responsible for the increase in tyrosine kinase activity. This is accomplished by isolating plasmid DNA from the strain which exhibits the elevated tyrosine kinase activity and characterizing the insert carried in the plasmid (e.g., by DNA sequence analysis). The molecule encoded by the cDNA insert can then be further characterized by conventional approaches such as expression and isolation of the encoded polypeptide followed by in vitro binding studies in order to confirm the specificity of the binding interaction with the transmembrane receptor.
The method of the present invention is not limited to the isolation of tyrosine kinase receptor ligands. Rather, the method can be modified for use in the identification of ligands for any transmembrane receptor having a single transmembrane domain, an extracellular domain and an intracellular domain. This is accomplished by generating an expression construct encoding a chimeric fusion protein comprising the extracellular domain of a transmembrane receptor fused to the intracellular domain of a specific tyrosine kinase receptor (e.g., the FGF receptor). As mentioned previously, this construct is preferably generated in a CEN-based plasmid background or, alternatively, in a plasmid which will facilitate integration of the chimeric receptor into the yeast chromosome. Conventional molecular biological techniques are employed to generate this construct, as well as all others disclosed in this specification (see e.g., Molecular Cloning: A Laboratory Manual, Maniatis et al., eds., Cold Spring Harbor Publications, Cold Spring Harbor, N.Y. (1989)). This expression construct encoding the tyrosine kinase receptor fusion protein is used in a manner analogous to the expression construct encoding the tyrosine kinase receptor in the embodiment described above.
Briefly, the preferred embodiment of this aspect of the invention includes the construction of a yeast strain which constitutively expresses a chimeric fusion protein of the type described above. This strain is then transformed with a cDNA expression library generated using mRNA isolated from the organism of interest. A ligand which binds specifically to the native transmembrane receptor will bind to the extracellular domain of the tyrosine kinase fusion protein and this ligand binding will trigger ligand-dependent intracellular tyrosine kinase activity mediated by the intracellular domain of the tyrosine kinase receptor. Intracellular tyrosine kinase activity is detected in the manner described previously.
A specific example of this embodiment of the present invention is applicable to the isolation of a ligand for a cytokine receptor (e.g., erythropoietin receptor, interleukin-3 receptor, etc.). Cytokine receptors, like tyrosine kinase receptors, are transmembrane receptors found in mammalian cells and possess both an extracellular domain and an intracellular domain. However, unlike the tyrosine kinase receptors, cytokine receptors do not possess a catalytic domain but rather recruit cytoplasmic tyrosine kinase enzymes in response to ligand activation. More specifically, the intracellular (cytoplasmic) domain of the cytokine receptor has been shown to bind to, and activate, a class of cytoplasmic tyrosine kinases (e.g., the JAK2/TYK2 class).
To isolate cytokine receptor ligands, a yeast strain is constructed which constitutively expresses a cytoplasmic tyrosine kinase and a transmembrane cytokine receptor. This yeast strain is then transformed with a cDNA expression library from an organism of interest, preferably under the control of an inducible promoter. Elevated levels of tyrosine kinase activity will be observed if the polypeptide encoded by the cDNA library insert functions as a ligand for the native cytokine receptor. Binding of the polypeptide ligand to the extracellular domain of the cytokine receptor (either at the plasma membrane or within a secretory vesicle) results in the activation of the cytoplasmic tyrosine kinase.
The colony Western blot procedure discussed above, and shown diagramatically in FIG. 2, is the preferred method for screening for an expression construct encoding a functional ligand. Specifically, a set of replica filters is prepared from the original transformation plate and the first and second replica filters are incubated overnight under inducing conditions, and non-inducing conditions, respectively. Colonies affixed to the replica filters are then lysed and probed with antiphosphotyrosine antibodies.
Increased levels of tyrosine kinase activity can be indicative of a cDNA insert encoding a ligand for the cytokine receptor or, alternatively, a cDNA insert encoding a cytoplasmic tyrosine kinase enzyme. To determine which of these two alternatives is responsible for the observed increase in tyrosine kinase activity, the expression construct encoding the candidate ligand is rescued and used to independently transform a first cell population which constitutively expresses the cytokine receptor and the cytoplasmic tyrosine kinase, and a second cell population which constitutively expresses the cytokine receptor but not the cytoplasmic tyrosine kinase. Candidates which demonstrate an increase in tyrosine kinase activity in the first cell population, but not the second, encode a cytokine receptor ligand. Expression constructs which result in an increase in tyrosine kinase activity in both the first cell population and the second cell population encode a cytoplasmic tyrosine kinase.
Given the fundamental disclosure that a yeast cell system can be used to identify ligands and other members of specific binding pairs involved in receptor-mediated molecular signaling, numerous variations of the theme described above are derivable through routine experimentation. Using such variations, any single polypeptide component of the receptor-mediated signaling pathway can be identified through the introduction of a cDNA library into yeast cells which have been modified to constitutively produce other necessary components of the signaling pathway.
For example, the methods described above can be modified to facilitate the identification of a cytokine receptor. As discussed above, cytokine-receptor mediated signaling involves a cytokine receptor and a cytoplasmic tyrosine kinase which is activated by interaction with the cytoplasmic domain of the cytokine receptor. As reported in the Exemplification section below, overexpression of the transmembrane tyrosine kinase (e.g., by expression from the GAL1 promoter) resulted in ligand-independent tyrosine kinase activity. By analogy, it would be expected that overexpression of a transmembrane cytokine receptor in the presence of a cytoplasmic tyrosine kinase would yield ligand-independent tyrosine kinase activity.
More specifically, a yeast strain constitutively expressing a cytoplasmic tyrosine kinase is first constructed. The use of the GAL1 promoter would be expected to result in a high level of cytoplasmic tyrosine kinase expression. However, routine experimentation may be required to optimize the expression level. It is preferred, for example, that the cytoplasmic tyrosine kinase be produced at such a level that it is detectable by Western blot.
A cDNA library is then constructed, preferably with the expression of the cDNA insert under the control of an inducible promoter. Replica filters are produced and incubated independently with, and without, a compound capable of inducing expression from the inducible promoter. Increased levels of tyrosine kinase activity are detected, for example, by colony Western blot in cells grown under inducing conditions, but not under non-inducing conditions. This would be observed, for example, when the cDNA insert encodes a cytokine receptor. The expression construct is rescued from these cells and introduced independently into yeast cells with, and without, constitutively expressed intracellular tyrosine kinase. Increased tyrosine kinase activity which is dependent upon the constitutively expressed cytoplasmic tyrosine kinase of the host strain indicates that the cDNA insert encodes a cytokine receptor. Increased tyrosine kinase activity which is not dependent upon the constitutively expressed cytoplasmic tyrosine kinase of the host strain is an indication that the cDNA insert encodes a functional tyrosine kinase. If such a cytokine receptor is known or discovered, yeast strains expressing the cytoplasmic tyrosine kinase and the cytokine receptor can be employed in a method for the isolation of a ligand in a manner analogous to the methods described elsewhere in this specification.
Another example of a variation of presently disclosed method is useful for the identification of a receptor for an orphan polypeptide ligand (i.e., a ligand for which no receptor has been previously identified), or for the identification of new receptors for a ligand which is known to interact productively with one or more previously identified receptors. This method incorporates the use of a yeast strain which has been modified to constitutively produce the previously identified ligand or orphan ligand. A cDNA library is introduced and the colony Western blot is employed to identify colonies which exhibit increased tyrosine kinase activity in the induced state. Rescue of the expression construct, followed by retransformation of yeast cells both with and without a constitutively expressed ligand, is used to confirm ligand-dependent activation of tyrosine kinase activity. It will be recognized that the description above relates specifically to a tyrosine kinase-like receptor. The method is easily modified for use with a cytokine receptor by adding constitutive cytoplasmic tyrosine kinase activity to the list of constitutive host cell requirements.
Similarly, the methods of this invention can be used to identify a cytoplasmic tyrosine kinase if a known cytokine receptor and ligand are provided. In this method, the cytokine receptor and ligand are expressed constitutively in a host yeast strain. The cDNA library is provided, and transformants are screened, in the induced and non-induced state, by the replica method discussed above. Candidate cytoplasmic tyrosine kinases are those encoded by an expression construct conferring increased tyrosine kinase activity in the induced state. The cDNA expression construct is rescued from the identified colony and introduced into yeast cells which constitutively express the cytokine receptor and ligand. The rescued construct is also introduced into a yeast strain lacking the cytokine receptor and ligand. Increased activity in the former, but not in the latter, is indicative of a cDNA insert encoding a cytoplasmic tyrosine kinase.
In another aspect of the invention, polypeptide modulators of receptor-mediated tyrosine kinase activity can be isolated. A polypeptide modulator can be, for example, a polypeptide (intracellular or extracellular) which modifies the affinity of the ligand for receptor, or which modifies the activity of the catalytic domain (either integral or recruited). Polypeptide modulators can be isolated by first providing a yeast strain which constitutively expresses a ligand/receptor pair (together with the cytoplasmic tyrosine kinase in the case of a cytokine receptor/ligand pair). The construction of such strains has been discussed in greater detail above. A yeast cell which constitutively expresses the ligand/receptor pair is expected to exhibit a relatively high level of background tyrosine kinase activity when the cDNA library is expressed in both the induced and non-induced state. However, the presence of a cDNA insert encoding a strong modulator (either an up-modulator or a down-modulator) will be determined by a detectable (i.e., at least about 2-fold) change in the level of tyrosine kinase activity in the induced state due to the presence of the polypeptide modulator.
In another aspect of the invention, ligands which specifically activate transmembrane tyrosine phosphatase receptors can be isolated. Transmembrane tyrosine phosphatase receptors are membrane components which have an intracellular catalytic domain which functions to remove phosphate groups from tyrosine residues. In other words, the tyrosine phosphatase receptor function can be viewed as a catalytic function which reverses the action of a tyrosine kinase (a tyrosine kinase functions by adding a phosphate group to intracellular tyrosine residues). Tyrosine phosphatase receptors have an extracellular domain and, therefore, the existence of extracellular ligands is presumed although none have been isolated to date.
In order to isolate a cDNA fragment encoding a tyrosine phosphatase receptor ligand, it is necessary to first provide a yeast strain which constitutively expresses cellular components necessary to produce a basal level of intracellular tyrosine kinase activity. This can be accomplished, for example, by providing a strain which constitutively expresses appropriate levels of a transmembrane tyrosine kinase receptor, together with its corresponding ligand. Basal levels of tyrosine kinase activity in such a strain are determined using the colony Western blot, for example.
Following a determination of intracellular tyrosine kinase activity, this strain is further modified to express a tyrosine phosphatase receptor. Subsequent to the introduction of the tyrosine phosphatase receptor gene, levels of tyrosine kinase activity are again determined to ensure that there has been no change in the basal level of phosphorylation detected. In the absence of the tyrosine phosphatase receptor ligand, the addition of the expressible tyrosine phosphatase receptor gene to the strain should not affect basal levels of phosphorylation.
Confirmation that the introduction of the tyrosine phosphatase gene does not affect detected phosphorylation levels is followed by the introduction of a cDNA library, preferably under the control of an inducible promoter. Replica filters are produced from the plate of transformants and incubated overnight under either inducing or non-inducing conditions. The levels of intracellular tyrosine phosphorylation are then determined, for example, by the colony Western blotting procedure. Reduced levels of intracellular tyrosine phosphorylation under inducing growth conditions, relative to the levels determined under non-inducing growth conditions, are an indication that the cDNA insert encodes a tyrosine phosphatase ligand which binds to the extracellular domain of the tyrosine phosphatase receptor thereby activating the tyrosine phosphatase activity which functions to reduce intracellular tyrosine phosphorylation thereby reversing the effect of the constitutively expressed tyrosine kinase. The initial indication that the cDNA insert encodes a tyrosine phosphatase ligand can be confirmed by further studies including, for example, demonstration that the observed decrease in phosphorylation is dependent upon entry of the cDNA encoded product into the secretory pathway. Confirmation that a signal sequence is encoded by the cDNA insert is an example of one type of confirmatory experiment.
The methods of the present invention can be further modified for use in the identification of functionally significant domains in a transmembrane receptor or its ligand. This method is carried out, for example, by mutagenizing either the transmembrane receptor or its ligand by conventional site-directed mutagenic techniques. The mutagenized component is then included in an assay of the type described above with a non-mutagenized copy serving as a positive control. Increased intracellular tyrosine phosphorylation in the positive control coupled with a relative decrease in tyrosine phosphorylation (relative to the positive control) in the assay which includes the mutagenized component indicates that the mutagenized amino acid residue(s) are of functional significance.
EXEMPLIFICATION
Disclosed in this Exemplification section are experiments which confirm a previously unproven hypothesis that it may be possible to functionally express a tyrosine kinase receptor and its corresponding polypeptide ligand in the same yeast cell, leading to activation of the receptor and a substantial increase in intracellular tyrosine phosphorylation. More specifically, using African clawed frog Xenopus laevis FGF receptor and FGF genes as a model system, it has been demonstrated that tyrosine kinase activity is triggered by co-expression of its ligand gene in yeast cells, provided that the ligand is capable of entering the secretory pathway. This activation of FGF receptor was detected by colony Western blotting which enables the screening of a large number of yeast transformants of a cDNA library. By screening a Xenopus cDNA library with a yeast strain expressing FGF receptor, two genes encoding novel growth factor-like ligands were identified, which can activate the FGF receptor by conventional pathways.
Materials and Methods
i) Yeast strains
A yeast Saccharomyces cerevisiae strain used in this study was PSY315 (Mat a, leu2, ura3 his3, lys2).
ii) Yeast transformation and media
The LiCl method (Ito et al., J. Bacteriol. 153:167 (1983)) was used for yeast transformation. Following media were used for yeast culture, YPD (1% yeast extract, 2% tryptone, 2% glucose), YPG (1% yeast extract, 2% tryptone, 2% galactose), SD (0.067% yeast nitrogen base w/o amino acids, 2% glucose), and SG (0.067% yeast nitrogen base w/o amino acids, 2% galactose).
iii) Plasmids
The vector plasmids pTS210 and pTS249 carry URA3 and LEU2, respectively, and both carry CEN4, GAL1 promoter and ACT1 terminator. The plasmid pKNA1 harbors LEU2, CEN4, ACT1 promoter and ACT 1 terminator.
Two types of plasmids for expression of Xenopus bFGF (basic fibroblast growth factor) in yeast were constructed: One plasmid is constructed by cloning bFGF gene into pTS210 (pTS-FGF) and a second plasmid is identical to the first except that a signal sequence of S. cerevisiae invertase (Carlson et al., Mol. Cell. Biol. 3: 439 (1983)) was inserted at the initiation codon of the bFGF gene (pTS-ssFGF). For FGF receptor expression, the Xenopus FGF receptor-1 gene (Musci et al., Proc. Natl. Acad. Sci. USA 87:8365 (1990)) was cloned into pTS249 and pKNA1 (pTS-FGFR and pKN-FGFR, respectively).
iv) Antibody
Anti-phosphotyrosine antibody 4G10 is purchased from Upstate Biotechnology Incorporated.
v) Colony Western blotting
Yeast transformants were plated on SD plates and incubated at 30° C. for two days. Colonies were transferred onto two nitrocellulose membranes (Millipore HATF 082). These membranes were placed colony-side up on SD and SG plates, and incubated overnight at 30° C. The membranes were placed on Whatman 3 MM filter paper presoaked with lysis buffer (0.1% SDS, 0.2 M NaOH, 35 mM DTT), and incubated at room temperature for 30 min. Colonies on the membranes were rinsed off with water, then the membranes were incubated in TBS-T(20 mM Tris-HCl pH 8.0, 150 mM NaCl, 0.05% Tween-20)-2% BSA (sigma) for blocking on a shaker for one hour, then incubated in 1:1,000-diluted anti-phosphotyrosine antibody (in TBS-T with 2% BSA) for one hour, and subsequently washed three times in TBS-T. The blots were then incubated in 1:10,000-diluted HRP(horse radish peroxidase)-conjugated goat anti-mouse Ig antibody (Bio-Rad) for one hour, and washed three times. Detection was done with chemiluminescence reagents (Amersham, ECL).
vi) cDNA library
The vector plasmid of the cDNA library is λyes (Elledge et al., Proc. Natl. Acad. Sci. USA 88: 1731 (1991)), which carries URA3, CEN4, ARS1, GAL1 promoter and HIS3 terminator. Two sources of cDNA were used for library construction. One was made from Xenopus XTC cells, The other was made from Xenopus unfertilized eggs and 10 hour embryos.
vii) Ca 2+ release assay
The procedure for the Ca 2+ release assay described in Amaya et al. (Cell 66:257 (1991)) was followed. Briefly, oocytes injected with certain mRNAs transcribed in vitro were incubated for two days, then incubated with 45 Ca 2+ for three hours. These oocytes were washed in 45 Ca 2+ -free medium, incubated in media for 10 minutes, followed by scintillation counting of the released radioactivity.
viii) Partial purification of EG2 protein
Yeast cells expressing the EG2 gene under control of GAL promoter were cultured in 1 L of YPG for eight hours (about 2×10 10 cells). Cells were collected and disrupted with glass beads in 20 ml of buffer A (20 mM Tris-HCl (pH 8.0), 1 mM EDTA, 1 mM PMSF), containing 150 mM NaCl. Cell debris were removed by low speed centrifugation (3,000×g for 5 minutes). The supernatant was centrifuged at 80,000×g for 20 minutes. The pellet was suspended in 5 ml of buffer A containing 1.2 M NaCl, then centrifuged with the same condition. The resulting pellet was suspended in 2 ml of buffer A containing 1% Triton X-100, and centrifuged with the same condition again. The supernatant was diluted 20 fold in modified Barth's saline (Gurdon, Meth. Cell Biol. 16: 125 (1977)) containing 0.5 mg/ml BSA.
Results and Discussion
To test whether co-expression of a receptor-tyrosine kinase and its ligand leads to the activation of the kinase in yeast cells, Xenopus laevis FGF receptor and bFGF were used as a model system. These genes were co-expressed in yeast cells under control of GAL1 promoter by co-transforming pTS-FGFR and pTS-FGF. In addition, bFGF fused with the SUC2 signal sequence (pTS-ssFGF) was also co-expressed with the FGF receptor gene because it is known that the bFGF gene does not have a signal sequence.
To determine whether the tyrosine kinase is activated in these strains, whole cell extracts were analyzed by immunoblotting with anti-phosphotyrosine antibody. The following results were obtained: (1) Expression of either bFGF or ssFGF alone had no effect on the level of tyrosine phosphorylation. (2) Expression of the FGF receptor plasmid led to a substantial increase in tyrosine phosphorylation of several endogenous proteins. (3) Co-expression of FGF receptor and ssFGF dramatically increased tyrosine phosphorylation to a level that was several times higher than the phosphorylation level observed after expression of the FGF receptor alone. (4) Co-expression of the FGF receptor and bFGF without a signal sequence did not lead to any increase in phosphorylation above that obtained after expression of the FGF receptor alone, although the same levels of the FGF proteins in the strains expressing the bFGF gene with and without the signal sequence are detected by immunoblotting with anti-FGF antibody. FGF could not be detected in culture supernatants, suggesting that the interaction was intracellular or periplasmic.
These findings demonstrate that it is possible to functionally co-express the FGF receptor and bFGF in yeast in such a way that they can interact productively in an autocrine manner and thereby lead to an increase in the FGF-receptor mediated phosphorylation of endogenous yeast proteins. bFGF with a signal sequence appears to interact with the extracellular domain of the FGF receptor on the cell surface or in internal membrane compartments, while bFGF without a signal sequence localizes in the cytoplasm and cannot interact with the receptor.
For screening of a large number of yeast transformants, a colony Western blotting method (Lyons and Nelson, Proc. Natl. Acad. Sci. USA 81:7426 (1984)) was developed. Yeast transformants expressing bFGF (with or without the signal sequence) and/or FGF receptor were plated on a glucose plate. Colonies were transferred to a filter and the filter was then placed on a galactose plate to induce bFGF expression. After overnight incubation, cells on the filter were lysed and the level of tyrosine phosphorylated proteins in each colony was determined by probing with anti-phosphotyrosine antibodies. The results of this experiment were essentially the same as those described above. That is, expression of the FGF receptor led to an increase in the level of tyrosine phosphorylation that was substantially augmented when bFGF containing a signal sequence was co-expressed, but not when bFGF lacking a signal sequence was co-expressed. These results indicate that the colony Western blotting method is sensitive and can be used to rapidly and easily screen thousands of different yeast colonies.
Several promoters have been tested for the expression of the FGF receptor gene in order to optimize the detection of its activation by colony Western blotting. They included the GAL1, ACT1 (actin; Gallwitz et al., Nucl. Acids Res. 9: 6339 (1981)), GPD1 (glyceraldehyde-3-phosphate dehydrogenase; Bitter and Egan, Gene 32: 263 (1984)) and TUB1 (α-tubulin; Schatz et al., Mol. Cell. Biol. 6: 3711 (1986)) promoters. Among them, the ACT1 promoter was determined to be most suitable. FGF receptor gene expression driven by GAL1 promoter proved very high, leading to high levels of tyrosine phosphorylation even in the absence of FGF, while the TUB1 promoter was extremely weak, such that FGF receptor activation by FGF could not be detected. Under the control of the GPD1 promoter, expression of the FGF receptor gene was repressed by galactose-containing media. On the other hand, the ACT1 promoter gave similar levels of FGF receptor gene expression in galactose- and in glucose-containing media, and levels of tyrosine phosphorylation were low in the absence of FGF, but significantly increased by expression of ssFGF. For these reasons, the ACT1 promoter was used for the cDNA screening experiment described below.
The above results encouraged further attempts to use this method to identify novel ligands for tyrosine kinase receptors. As a first step, the method was used to identify new ligands for the FGF receptor. The purpose of this experiment is two-fold: first, to determine whether this system can be used to identify genuine FGF genes, and second, to isolate previously unidentified activators of the FGF receptor.
The procedure followed is outlined diagramatically in FIG. 1. Yeast cells expressing the FGF receptor were transformed with a cDNA library expected to contain FGF gene family members. Since bFGF (Kimelman et al., Science 242: 1053 (1988)), embryonic FGF (Isaacs et al., Development 114: 711 (1992)) and int-2/FGF3 (Tannahill, et al., Development 115: 695 (1992)) are known to be expressed in Xenopus embryos, we used a cDNA library made from mRNA isolated from Xenopus eggs and embryos (egg library). A library made from XTC cells was also used (XTC library).
150,000 and 25,000 transformants were obtained from the egg and XTC libraries, respectively. In the first screening by colony Western blotting with an anti-phosphotyrosine antibody, 65 and 29 candidates were identified, and by the second screening, nine and two transformants were found to be positive (egg and XTC library, respectively). Plasmid DNA in each transformant was rescued, and re-transformed into yeast strains with and without the FGF receptor gene in order to test whether the positive signal is dependent on expression of the FGF receptor gene. Only one plasmid rescued from one of the egg-library transformants was found to be positive even in the absence of the receptor gene expression. The other genes increased tyrosine phosphorylation only when the FGF receptor gene was co-expressed.
The DNA sequence of the genes present on these plasmids was determined (Table 1). Two genes encoded peptide factors with putative signal peptide sequences. One gene, designated XT1, encodes a protein with some homology to bovine angiogenin and Chinese hamster pancreatic ribonuclease A (about 30% identity; (Maes et al., FEBS Letter 241: 41 (1988); Haugg and Schein, Nucl. Acids Res. 20: 612 (1992)). The other, EG2, is homologous to cripto, which is an EGF family member, identified in both mouse and human (about 30% identity; Ciccodicola et al., EMBO J. 8: 1897 (1989); Dono et al., Development 118: 1157 (1993)). Angiogenin, like FGF, is an angiogenesis-promoting factor. Cripto is suggested to have a role in mesoderm by virtue of its embryonic localized induction. Receptors for angiogenin and cripto have not yet been identified. Taking these facts into account, XT1 and EG2 gene products could be novel ligands of the FGF receptor.
The XT2 encodes a putative protease homologous to cathepsin L (58% identity with human cathepsin L; Joseph et al., J. Clin. Invest. 81: 1621 (1988); Gal and Gottesman, Biochem. J. 253: 303 (1988)). This protease might cleave the FGF receptor in yeast cells, and the cleaved fragment might have an elevated tyrosine kinase activity. EG1 was previously identified in Xenopus laevis as a heterogeneous ribonucleoprotein (Kay et al., Proc. Natl. Acad. Sci. USA 87.: 1367 (1990)). EG3 has an RNA recognition motif found in many RNA binding proteins (Kim and Baker, Mol. Cell. Biol. 13: 174 (1993)). These RNA binding proteins might increase synthesis of FGF receptor protein by increasing the efficiency of transcription or translation. Elevated expression induces autophosphorylation.
EG4 encodes a novel 96 kDa protein. Recently, a gene similar to EG4 was found in C. elegans (39% identity), but its function is unknown (Wilson et al., Nature 368.: 32 (1994)). The plasmid which was positive even in the absence of the FGF receptor gene harbored a gene encoding a putative tyrosine kinase homologous to mouse cytoplasmic tyrosine kinase FER (Hao et al., Mol. Cell. Biol. 9: 1587 (1989)).
XT1 and EG2, which have been identified as activators of the FGF receptor in yeast, were tested to determine whether they could also activate the FGF receptor expressed in higher eukaryotic cells. Since it is known that the activation of FGF receptor in Xenopus oocytes is linked to a rapid Ca 2+ release from internal stores (Johnson et al., Mol. Cell. Biol. 10: 4728 (1990)), Ca 2+ release assays were performed with Xenopus oocytes expressing FGF receptor.
As for EG2, the EG2 protein was partially purified tagged with a flag epitope expressed in yeast. The oocytes expressing FGF receptor were labeled with 45 Ca 2+ treated with EG2, followed by Ca 2+ release assay. It was found that Ca release was stimulated by treatment of partially purified EG2 protein.
As for XT1, this protein has not been expressed efficiently enough to purify the protein, so instead, XT1 mRNA was co-injected with FGF receptor mRNA into oocytes. If XT1 protein activates the FGF receptor in oocytes, it is expected that the FGF receptor would be constitutively activated by the continuous synthesis of XT1 protein, and that the basal level of Ca 2+ efflux in the co-injected oocyte would be higher than in oocytes injected FGF receptor mRNA alone. Ca 2+ efflux of labeled oocytes was measured, and it was found that co-injection of XT1 and FGF receptor mRNAs increased Ca 2+ release two-fold more than the injection of FGF receptor message alone. Co-injection of bFGF and FGF receptor mRNA increased Ca 2+ release three-fold. XT1 or bFGF mRNA alone did not increase Ca 2+ release.
These results demonstrate that XT1 and EG2 can activate FGF receptor expressed in Xenopus oocytes, and that these protein synthesized in vivo can work as activators of FGF receptor. In order to demonstrate that these proteins are real ligands for FGF receptor, it will be necessary to show that these proteins bind directly to an extracellular domain of the FGF receptor.
TABLE 1______________________________________Genes Which Increase Protein-Tyrosine Phosphorylation inYeast Cells Expressing FGF Receptor.FGF receptor frequencygene dependency gene product of isolation______________________________________1) secreted proteinsXT1 + homologous to angiogenin 1 and RNaseAEG2 + cripto (EGF-like growth 4 factor)XT2 + 58% identical to human 1 cathespin L2) RNA binding proteinsEG1 + heterogeneous 2 ribonucleoproteinEG3 + RNA binding protein 13) a novel proteinEG4 + novel 96 kd protein 14) FGF-receptor independentEG5 - cytoplasmic tyrosine 1 kinase TER______________________________________ | Disclosed herein are compositions and methods which are useful in the identification and isolation of components involved in transmembrane receptor-mediated signaling. Such components include the receptors themselves (e.g., tyrosine kinase receptors, cytokine receptors and tyrosine phosphatase receptors), as well as ligands which bind the receptors and modulators of the downstream intracellular catalytic event which characterizes receptor-mediated signalling. | 50,738 |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims the benefit of U.S. Provisional Patent Application No. 61/570,233, filed Dec. 13, 2011, which is hereby incorporated by reference.
BACKGROUND
[0002] Partitions for passenger vehicles are used to separate the interior space for different uses. According to one common type of partition used in law enforcement vehicles, the rear seat area (typically suited for two passengers) is separated from the front seat area (typically suited for a driver and a passenger) by a partition. This type of partition separates one or two law enforcement officers seated in the front seat area from one, two or sometimes three rear seat occupants, such as suspects and other individuals, thereby reducing the risks of injury to the law enforcement officers from the rear seat occupants, as well as restricting the ability of the rear seat occupants to escape from the vehicle.
[0003] Law enforcement officers spend many hours in their vehicles each day, so vehicle partition mounting schemes that provide a full range of front seat adjustment, both in terms of fore-aft translation of the seat and pivoting of the seat back, are highly sought after. At the same time, however, law enforcement vehicles are becoming smaller because of the need for greater fuel economy. In addition, rear seat legroom is also compromised in today's newest vehicle models that are used in law enforcement. In some cases, it is necessary to compromise and provide for full adjustability of the driver's seat and less adjustability of the front passenger seat while also seeking to maximize the available rear seat legroom within a number of constraints. It would be beneficial to maintain or increase the free area available to rear seat occupants for ingress into and egress from the vehicle.
SUMMARY
[0004] Described below are implementations of a partition that address some of the problems of conventional partitions.
[0005] According to one implementation, a partition for separating front and rear occupant areas of a vehicle comprises at least one partition member and at least one pair of partition support brackets. The partition member has an upper extent comprising a near ceiling member positionable adjacent a ceiling of the vehicle and two lateral extents comprising opposite side members. The pair of partition brackets is mountable to opposite sides of the vehicle and to the opposite side members of the partition member to couple the partition to the vehicle. The partition support bracket for at least one of the opposite sides comprises a load support section configured to support a proportion of a partition member load as applied to that side.
[0006] The at least one bracket can comprise an internal bracket component and an external bracket component. The internal bracket component can be configured to be mounted to a pillar of the vehicle. The external bracket can be configured for coupling to the internal bracket component. The internal bracket component and the external bracket component can together define an intermediate space dimensioned to receive a trim panel for the pillar of the vehicle. The internal bracket component can comprise screw bosses for receiving threaded fasteners to couple the external bracket component to the internal bracket component. The screw bosses can be dimensioned to maintain a space between the internal bracket component and the external bracket component.
[0007] The partition support bracket can be a sole load supporting member for partition member forces and other associated forces carried by the respective side of the vehicle. Each of the pair of the partition support brackets can be a sole load supporting member to transfer forces exerted by the partition to the respective side of the vehicle. The partition support bracket can have a generally planar cross-section.
[0008] At least one of the side members of the partition member can be dimensioned to terminate at a height above a knee height when the partition is installed in a vehicle. Stated differently, the partition member can be “legless” on at least one side. In another implementation, the side members of the partition member extend away from the near ceiling member, and both are dimensioned to terminate above a knee height as defined by a typical seated rear seat occupant's knees when the partition is installed in a vehicle.
[0009] The internal bracket component can be configured for mounting to a B-pillar of the vehicle. At least one of the pair of support brackets can define a large opening therein. The internal bracket component can be comprised of two separate pieces. The internal bracket component can comprise a body and out turned flanges. The load support section of the at least one of the partition support brackets can be shaped to extend over a space between a side surface of the vehicle and the partition member when the partition is installed in the vehicle.
[0010] The at least one of the support brackets can be configured to maintain an open feet access area when the partition is installed to ease ingress and egress through a door opening for a rear seat occupant. The at least one of the support brackets can be configured to support the partition frame spaced rearward of a B-pillar of the vehicle by a greatest distance of about 4 inches to about 6 inches when the partition is installed in the vehicle.
[0011] In another implementation, a partition for separating two-passenger front and multiple-passenger rear occupant areas of a vehicle comprises a partition frame, one or more panel members and a tubular extension. The partition frame has an upper lateral member, respective angled side tubular members extending from ends of the upper lateral member, and a window bordered by the upper lateral member and the side members. The one or more panel members are configured to fit between the window and a floor pan of the vehicle in a vertical direction and between first and second sides of the vehicle in a horizontal direction. The tubular extension is positionable to support one of the angled side tubular members for positioning adjacent the first side of the vehicle. The tubular extension has a lower end configured for coupling to a midsection of the vehicle. A first of the body panel members is positionable adjacent the tubular extension and generally defines a first body member plane approximately parallel to a reference plane defined by the tubular extension and the window. There is at least a second body panel member positionable laterally adjacent the first body panel member and for positioning adjacent the second side of the vehicle. The second body panel member has a recessed portion recessed in a forward direction relative to the first body panel to increase space available for a rear seat occupant on the second side of the vehicle.
[0012] The recessed portion can comprise a foot well having a further recessed portion sized to accommodate at least a portion of a rear seat occupant's feet. In some implementations, there is no tubular extension positionable to support the other of the angled side tubular members for positioning adjacent the second side of the vehicle.
[0013] The partition can be configured for withstanding loads applied to the partition and transmitted through the brackets to the vehicle by connections to the vehicle's midsection at heights above a floor level of the vehicle. The partition can be configured for attachment to the vehicle's B-pillars.
[0014] These and other implementations are described below in greater detail.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] FIG. 1 is an exploded perspective view of an embodiment of the partition providing increased legroom.
[0016] FIG. 2 is an elevation view of a rear side of the partition of FIG. 1 as would be seen from the rear seat of the vehicle, also showing an imaginary second support member in dashed lines.
[0017] FIG. 3 is an elevation view of a right side (passenger side) of the partition of FIG. 1 .
[0018] FIG. 4 is a rear side perspective view of the partition of FIG. 1 , showing the right side of the partition.
[0019] FIG. 5 is another rear side perspective view of the partition of FIG. 1 , showing the left side (driver's side) of the partition.
[0020] FIG. 6 is a front side perspective view of the partition, also showing an optional gun mount.
[0021] FIG. 7 is an exploded perspective view of a partition similar to FIG. 1 , except showing different configurations for several components.
[0022] FIG. 8 is a front side perspective view of a partition similar to FIG. 1 , except showing different configurations for several components.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0023] An embodiment of a partition 10 providing increased legroom is shown in FIGS. 1-6 . The partition 10 (or partition assembly) includes a partition frame 12 and at least a pair of partition support brackets 20 , 22 that couple the partition 10 to a vehicle. In the illustrated implementations, the partition is configured to be coupled to the vehicle's inner surface at approximately the B-pillar of the vehicle, and at a height above the floor pan and door opening (or door sill). In the illustrated implementations, the partition is coupled to the vehicle at a height below the window glass, but in other applications, this connection between the partition and the vehicle may occur at points above the vehicle glass.
[0024] The partition frame 12 includes a near ceiling member 14 configured to positioned near the ceiling of the vehicle. The near ceiling member 14 is connected at each end to side members 16 via transition sections 18 . For vehicles equipped with side curtain air bags, the side members 16 are configured for positioning at least some distance away from the adjacent surfaces of the vehicle's interior, and the resulting spaces are covered or filled by the panels 34 . The panels 34 (or their fasteners) may deform, detach, pivot and/or otherwise change condition to allow the side curtain air bags to operate without impediment when deployed. For example, the panels or their fasteners may be bendable to allow deformation upon deployment of an air bag.
[0025] There is a window assembly 36 mounted within the partition frame 12 . The window assembly may have one or more movable windows. In some implementations, the lower extent of the partition is defined at about the location of the lower horizontal window frame member.
[0026] In the illustrated implementations, the left side of the partition frame 12 includes a vertical support member 32 that extends downwardly from the corresponding side member 16 . The vertical support member 32 is coupled to the vehicle by a bracket 40 shaped to receive a tubular end of the vertical support member 32 . Although the bracket 40 as illustrated is configured for positioning well above the floor or floor pan level of the vehicle, the bracket 40 and the member 32 protrude into the open space available to a passenger seated behind the driver. There may be a spacer 42 located between the member 32 and the bracket 40 . In other implementations, the member 32 and the bracket 40 are formed as a single piece.
[0027] At the right side of the partition, the side member 16 terminates at 19 , i.e., defining a knee space for an occupant seated in the other rear seat behind the front passenger seat. There is a seat back section 46 that has a center section connected to a left side seat back panel 38 and to a recessed right side seat back panel 50 . Although the left side seat back panel 36 is shown as part of the partition frame 12 , it can be formed as a single piece. Similarly, although the recessed right side back panel 50 is shown to be formed as a portion of the seat back section 46 , it can be formed as a separate piece. The left side may be fitted with a lower extension panel 44 that substantially fills the space between the lower edge of the left side seat back panel 38 and the floor pan of the vehicle.
[0028] Conveniently, the seat back panel 38 , the lower extension panel 44 , the seat back section 46 and the recessed seat back panel 50 can be formed of sheet metal, plastic, or other suitable material. In general, these components do not bear any significant loads.
[0029] In FIGS. 2 and 3 , an imaginary support member or “leg” L, similar in dimension and position to the support member 32 is shown. Conventionally, known partitions have a generally symmetrical construction, and thus would interpose such a member L (and its corresponding bracket, which is not shown) into the rear seat space, despite other efforts to increase that space (e.g., such as providing the recessed right side back panel 50 ). It has been discovered, however, that greater legroom and ease of access are achieved if the leg L is eliminated and the load from the partition is instead carried by the bracket 20 . Thus, the bracket 20 provides structural support and is the predominate member by which loads are transferred from the partition frame 12 to the vehicle.
[0030] The external bracket 28 can be formed with an extension 54 that allows the partition frame 12 (in the area of 19 ) to be coupled by the internal bracket 24 to the vehicle over a significant setback distance S ( FIG. 3 ) from the axis of the B pillar, which shown by the line B. In various implementations, the setback distance S can be about 3 inches to about 6 inches. In other implementations, depending upon vehicle geometry, the setback distance may be less than 3 inches
[0031] Because of the extension 54 and the setback distance S, the body 56 of the external bracket component is also configured to fill the gap, i.e., to cover the space between the partition frame and the nearest inner surface of the vehicle. This maintains the integrity of the partition, e.g., in preventing a rear seat occupant from reaching through a gap to access the front seat area.
[0032] The various components may be assembled together using conventional threaded fasteners, such as bolt 80 . Referring to FIG. 6 , the bracket components 24 and 28 , and the bracket components 26 and 30 , can be spaced apart so that the vehicle's trim panel can be reinstalled after the respective internal bracket components 24 and 26 are coupled to the vehicle and before the external bracket components 28 and 30 , respectively, are connected. Screw bosses 62 are one example of suitable spacers.
[0033] The brackets 20 , 22 can be formed of any suitable material for carrying the loads transferred from the partition, such as, e.g., 3/16″ to ¼″ steel plate. Although the bracket components 26 , 30 and 24 , 28 are shown as single pieces, any may be formed in multiple pieces, depending upon the specific requirements. Each bracket 20 , 22 is attached to the vehicle with at least three fasteners. In general, pairs of fasteners are arranged at approximately the same level. The bracket components can be provided with flanges, such as the flange 60 , to make securing the components to each other or to the vehicle more convenient and secure.
[0034] FIG. 7 is an exploded perspective view of a partition according to another implementation viewed from its rear side. The partition 110 is similar to the partition 10 shown in FIG. 1 , and like elements have the same reference numbers, plus 100 . The differences between the partition 110 and the partition 10 are as follows: (1) the lower extension panel 144 is taller than the lower extension panel 44 , (2) the corresponding left side back panel portion 138 does not extend as far below the level of the partition window as in the back panel portion or back panel 38 , (3) in the seat back section 146 , the lower edge 147 is at a greater height than a corresponding edge in the seat back portion 46 , and (4) a foot well 151 with one or more forwardly oriented recesses is provided. The lower extension panel 144 illustrates another example of how in the area behind the driver's seat and between the lower edge of the window and the floor of the vehicle, there can be a single panel, a combination of multiple panels or, in some cases, no panel. Also, the bottom portion of the panel 144 can be formed as shown to conform to the contours of the vehicle's floor pan to prevent gaps, yet extend forwardly to provide as much space in the rear compartment as possible, while still maintaining full adjustability of the driver's seat position. In the same way, the lower edge 147 can be a greater height as shown to conform to a vehicle having a greater vertical feature at that location. The foot well 151 can be formed into a separate panel 153 attached to a bottom edge of the seat back panel 150 , or it can be formed as one piece with the panel 150 .
[0035] FIG. 8 is an exploded perspective view of a partition according to another implementation viewed from its front side. The partition 210 is similar to the partition 10 or the partition 110 , and like elements have the same reference numbers as in FIG. 1 , plus 200 . In the partition 210 , the lower extension panel 244 has a geometry configured to follow the contours of a different vehicle's floor pan, and includes a deep recess to receive at least a portion of a rear seat occupant's feet. In the partition 210 , the foot well 251 is configured as a separate piece that is attached to the seat back panel 250 . FIG. 8 illustrates another example of brackets 224 and 226 having respective openings 231 and 233 . The openings 231 , 233 are provided to allow the brackets to be installed over projecting elements of the vehicle seatbelt assemblies, which extend through the openings when the brackets are installed, maintaining their full operational capabilities.
[0036] Thus, with the illustrated implementations, it is possible to provide a partition that allows for the driver's seat to have full range of motion (translation fore and aft and pivoting of the seat back), even in today's smaller vehicles, ensuring enhanced legroom. At the same time, increased rear seat legroom is provided for one rear seat occupant on the opposite side, i.e., in the seat behind the front passenger seat. (The front passenger seat area is reduced somewhat, but is still fully usable.) By maintaining an open access area, particularly at lower heights where a rear seat occupant needs to move his feet, ingress and egress are improved. Specifically, by minimizing the portions of the partition that would protrude into the forward open area defined by the door opening/door sill and the vehicle's vertical side surface (generally, the vehicle's B pillar), the rear seat occupant can move into and out of the seat without maneuvering his feet around a support member attached to the floor pan or protruding rearward of the seatback and/or striking his knees on the seat back. The open access area as described can provided for one rear seat occupant as shown, or in a full “legless” partition providing increased access for both rear seat occupants.
[0037] In view of the many possible embodiments to which the principles of the disclosed invention may be applied, it should be recognized that the illustrated embodiments are only preferred examples of the invention and should not be taken as limiting the scope of the invention. Rather, the scope of the invention is defined by the following claims. We therefore claim as our invention all that comes within the scope and spirit of these claims. | A partition for separating front and rear occupant areas of a vehicle comprising at least one partition member and at least one pair of partition support brackets. The partition bracket has an upper extent comprising a near ceiling member positionable adjacent a ceiling of the vehicle and two lateral extents comprising opposite side members. The partition support brackets are mountable to opposite sides of the vehicle and to the opposite side members of the partition member to couple the partition to the vehicle. The partition support bracket for at least one of the opposite sides comprises a load support section configured to support a proportion of a partition member load as applied to the at least one of the sides. | 20,306 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the use of back-scattered microwave radiation for non-invasive monitoring and diagnostics of biological activity, physiologic activity, anatomical structure and the pathology of various organs of living animals and man.
2. Description of the Prior Art
The use of microwaves in monitoring biological activity and pathological diagnostics is receiving more and more attention, particularly because microwaves are capable of penetration of soft tissue and can be used in non-invasive techniques for monitoring the heart, brain and other organs. Two examples of such techniques are disclosed in U.S. Pat. Nos. 3,483,860 to Namarow and 3,951,314 to Malech.
U.S. Pat. No. 3,483,860 to Namarow discloses a method for monitoring intrasomatic circulatory functions and organ movement wherein low power microwave signals are modulated with an audio frequency and transmitted through a horn antenna positioned on a subject's chest. A portion of such signals is reflected back and received through a directional coupler. The received signals are modulated in accordance with heart action, i.e. variations in blood flow during the pumping cycle and movement of the heart and adjacent bodily organs. The modulated signals are amplified and demodulated in a receiver, the modulation envelope being impressed on the audio carrier frequency. While providing an important diagnostic tool, because of the use of a horn antenna large areas are irradiated and it is not possible to isolate for diagnosis small localized areas. Also, since the system depends on variations in blood flow or muscle or heart movement, it cannot be used for medical diagnosis of areas such as the brain which is free from movement or the spine which is substantially transparent to microwaves.
U.S. Pat. No. 3,951,134 to Malech discloses a method and apparatus for remotely monitoring brain waves. Electromagnetic signals of different frequencies are simultaneously transmitted to the brain of the subject. It is suggested that the signals of different frequencies penetrate the subject's skull and mix to form an interference waveform which is modulated by brain activity. The modulated interference waveform is re-transmitted from the brain and picked up by the antenna and processed in received electronics to develop a signal representing intra-brain activity. While the Malech patent provides a means of monitoring brain function which may be a useful barometer of organic functions, it is too technically cumbersome to be accepted as a general diagnostic tool by the general practioner.
Over the years researchers have reported various techniques for using microwaves as a means for biological studies and reference may be made to the following publications.
(1) C. Susskind, "Possible Use of Microwaves in the Management of Lung Disease," Proc. IEE, Vol. 61, pp. 673-74 (May 1973);
(2) C. Susskind and A. R. Perrins, "Oscillograph Field Plotter," Electronics, Vol. 24, pg. 140 (September 1951);
(3) P. C. Pedersen et al., "An Investigation of the Use of Microwave Radiation for Pulmonary Diagnostics," IEEE Transactions on Biomedical Engineering, Vol. BME-22, pp. 410-12 (September 1976);
(4) P. C. Pedersen et al., "Microwave Reflection and Transmission Measurements for Pulmonary Diagnosis and Monitoring," IEEE Transactions on Biomedical Engineering, Vol. BME-25, pp. 40-48 (January 1978);
(5) D. G. Bragg et al., "Monitoring and Diagnosis of Pulmonary Edema by Microwaves: A Preliminary Report," Investigative Radiology, Vol. 12, pp. 289-91 (May-June 1977);
(6) D. W. Griffin, "MW Interferometers for Biological Studies," Microwave Journal, Vol. 21, pp. 69-72 (May 1978);
(7) H. P. Schwan, "Microwave Biophysics," Microwave Power Engineering, E. C. O'Kresss, ed. (Academic Press. 1968) pp. 213-34;
(8) O. M. Salati et al., "Radio Frequency Radiation Hazards," Electronic Industries, pp. 96-101 (November 1962);
(9) J. Yamaura, "Mapping of Microwave Power Transmitted Through the Human Thorax," Proceedings of the IEEE, Vol. 67, pp. 1170-71 (August 1978; and
(10) J. C. Lin et al., "Microwave Apexcardiography," IEEE Transactions on Microwave Theory and Techniques, Vol. MT-27, pp. 618-20 (June 1979).
While much research has been funded to develop microwave techniques for diagnostic testing and large amounts of funds have been spent in the development of sophisticated laboratory electronics to support such research, little attention has been paid toward the development of diagnostic instruments or tools capable of every day use by the general practioner. Perhaps one reason for the absence of interest in this area is the traditional reluctance of medical practioners in deviating from accepted practice and the use of tools or instruments radically different from those which have served the profession well over the years.
SUMMARY OF THE INVENTION
It is a primary object of the present invention to provide a microwave diagnostic instrument for probing and monitoring on-going biological activity, physiologic activity, anatomical structure and the pathology of various organs of living animals and man.
Another object of the present invention is to provide a portable microwave diagnostic instrument which can operate at safe levels of radiation and which can be used for monitoring heart and other organ activity and to study activities of the brain and spinal cord.
A further object of the present invention is to provide a portable microwave diagnostic instrument that may be used as a substitute for a stethoscope by converting localized heart activity into monaural or binaural sounds.
Still another object of the present invention is to provide a portable diagnostic instrument capable of monitoring electrical activity of the brain and spinal cord.
Accordingly, the present invention relates to a method and apparatus for directing and concentrating a low power level microwave signal on localized body areas such as the heart and other organs, spine and brain to non-invasively monitor on-going biological or neural activity. A Gunn diode feeds power into one end of a short, insulated dielectric wave guide, the free end of which houses a point contact semiconductor isolated by a metal shield from the incident beam. The wave guide concentrates and directs a pencil shaped beam through the free end onto a small localized area. Back scattered radiation is detected, filtered, amplified and recorded to reflect on-going biological or neural activity. The microwave instrumentation is housed to form a compact portable unit capable of being carried by a physician much the same way as a stethoscope and includes two ear tubes connected to receive the audio output of the amplifier through an audio converter to provide a monaural or binaural signal indicative of the on-going biological or neural activity.
A BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and advantages of the invention will be further apparent from the following description and the accompanying drawings which form part of the instant specification and which are to be read in conjunction therewith, and in which like reference numerals are used to identify like parts throughout the several views.
In the drawings, FIG. 1 is a perspective view of a "microprobe" in accordance with the present invention;
FIG. 2 is a enlarged, fragmentary view of the free end of the waveguide shown in FIG. 1 within the dash line circle;
FIG. 3 is a diagramatic view of a microwave diagnostic instrument in accordance with the present invention;
FIG. 4 is a partial diagramatic and enlarged view of the microwave diagnostic instrument of FIG. 3 showing a further embodiment of the "microprobe" in elevation with part of the housing removed for clarity;
FIG. 5 is a bottom view of the "microprobe" of FIG. 4 looking into the waveguide exit ports;
FIG. 6 illustrates a typical laboratory set up for the present invention for detecting heart activity in a mouse;
FIG. 7 is a combined schematic and diagramatic view of an amplitude to frequency converter in accordance with the present invention;
FIG. 8 illustrates modulated and microwave signals as recorded at various locations on the chest of a mouse using the microprobe of the present invention;
FIG. 9 shows a graphical representation of a target area scanned by the microprobe of the present invention;
FIG. 10 shows the modulated microwave signal response taken along different points of the target area of FIG. 9;
FIG. 11 shows a modulated, microwave signal response from a human heart taken at three different positions;
FIG. 12 shows modulated, microwave signals developed from matched diodes arranged in a semi-circular pattern on the dorsal surface of the head of an animal;
FIG. 13 shows recordings obtained from the occipital regions of a head of an animal when stimulated with a light source; and
FIG. 14 shows recordings obtained from the spinal cord of an animal.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, there is shown the "heart" of the microwave monitoring system of the present invention which for convenience will be referred to as the "microprobe" 10. Microprobe 10 comprises a conventional miniature self-contained Gunn diode 12 and associated resonating chamber 13 formed by planar walls and having an output window 14 in one wall. Diode 12 is powered by a suitable DC voltage supply not shown in FIG. 1. The DC supply may be a well known type such as Thornton model MWG-103, or batteries.
Gunn diode 12 has its output window 14 coupled to one end of a tapered dielectric waveguide 16 mounted to wall 18 of resonating chamber 13. Guide 16 has a decreasing or reducing taper in the direction of its output end. As shown in FIG. 1, waveguide 16 is truncated to form a frustum of a solid regular trapezoid and has a small groove 20 cut into the free end of the waveguide forming microwave exit ports 22 and 24 to each side of the groove. Groove 20 is lined with a metallic shield 26 which may be of aluminum or copper as shown more clearly in FIG. 2 and a detector diode 28 is mounted within the groove which together with the reflector serves as a housing for the small diode detector. Negligible power due to field fringing is received at the detector unless an object is placed in front of the waveguide to produce backscattering of radiation. The outer planar surfaces of waveguide 16 may also be provided with a metallic shield 27 of aluminum foil or copper foil. Other metal layers such as gold or silver may also be utilized. Such a shield is not essential for operation of the microprobe; however, the shield improves microwave response and cancels stray fields.
Waveguide 16 is preferably a solid dielectric such as plexiglass; however, any suitable plastic transparent to microwaves may be used. The material selected should be such that the impedance at the exit ports 22-24 approximates the impedance of the subject to be monitored, i.e. the surface against which the microprobe is pressed. To this end, the impedance of the waveguide may be modified by incorporating into the plastic suitable fillers such as titanium dioxide to change the dielectric constant of the solid material forming the waveguide. While waveguide 16 is shown as having flat tapering sides forming a solid regular trapezoid, other shapes will readily suggest themselves. For example, waveguide 16 may take the form of a truncated cone. It is, however, important that the dielectric waveguide 16 tapers to a gradually reduced cross section at the output end such that the microwave power output signal from the Gunn diode 12 is polarized and focused into a beam as it passes through the inside of the dielectric guide. The cross sectional area of the output end of the guide at exit ports 22 and 24 should be approximately 1 square centimeter. The high refractive index of the dielectric serves to shorten the effective wavelength and allows propagation of the beam through the exit ports 22 and 24 at the end of the waveguide in the order of 1 square centimeter or less. Thus, there is provided a highly localized beam which enables diagnostic measurements to be made of discreet areas of organs. The localization can be further restricted by increasing the frequency of the microwave source. In the preferred embodiment, the diode provides a continuous frequency output of 10 gigahertz. However, by varying the diode and resonating chamber, the output frequency of the emitted signal can be changed over a wide range of, say, 5 gigahertz to 20 gigahertz.
The continuous wave output radiation has a total power output level of less than 10 milliwatts. Thus, monitoring of biophysical activity of a life system can be accomplished safely with a minimum of hazard to the life system. The penetration depth, defined as the distance to attentuate the beam power to 1/e of the incident level for a 10 gigahertz wave is 0.34 cm. in high water content tissue and 3.0 cm. in fat or boney tissue. The wavelength in these two types of tissue are 0.46 cm. and 1.41 cm. respectively.
Many geometries are possible for detecting scattered microwave radiation at all angles from 0° to 180°. The microprobe 10 may be scanned slowly across the area of the life system or subject being monitored and evaluated or several detectors may be arranged in an array. It is also possible to detect backscattered waves by physically separating the detector 28 from the microprobe 10. This advantageously enables one to obtain spatial distribution of the scattered waves. However, in the preferred embodiment the detector diode 28 is disposed at the center of the exit end of the waveguide, centrally disposed between ports 22 and 24. This arrangement provides a better signal to noise ratio and minimizes power level requirements.
Referring to FIG. 3, there is illustrated a portable microwave diagnostic instrument constructed in accordance with the present invention. As should be apparent, the instrument is specifically designed to approximate the physical appearance of a stethoscope. To this end, microprobe 10 is housed in a T-shaped cylindrical casing 30 having a flat surface 32 adapted to be placed against the skin of the subject. Diaphragm 32 includes a central window shaped to correspond to the output end of waveguide 16 and is in flush engagement with the outer perimeter of the exit end of the dielectric waveguide. A shielded cable 33 provides the necessary electrical connections between microwave source diode 12 and detector diode 28 to a solid state miniaturized integrated circuit conveniently packaged in casing 30. The integrated circuit includes a power source 36, amplifier 38 and a voltage to frequency converter 40 which provides an audio output signal correlated to the biophysical activity of the subject which in the case of FIG. 3 is cardiac activity. The output of the voltage to frequency converter is coupled via cable 42 to a pair of ear tubes 44 and 46 extending from spring member 48. Spring member 48 enables the ear tubes to be spread apart for insertion into the ears in a conventional manner. The output of the circuit may be monophonic or split between the two ear tubes to provide a binaural response.
As should be readily apparent, the packaging of the integrated circuit board enables the control components, together with the ear piece and microprobe element 10 to be slipped into and conveniently carried in a coat pocket, much the same as a stethoscope. Further miniaturization of the circuits onto semiconductor chips in accordance with conventional technology enables the power source 36, amplifier 40 and voltage to frequency converter 34 to be advantageously housed within the casing 30 for the microprobe element. To this end, as shown in FIGS. 4 and 5, Gunn diode 12 fits snugly within the upper section 31 of casing 30 which is of a reduced dimension compared to the base portion 33 of the casing. The area within the casing 30 and around waveguide 16 forms a cavity 52. At one end of cavity 52 is mounted a semiconductor chip 54 comprising the amplifier stages 38 and voltage to frequency converter 40. To the other side of cavity 52 is mounted power source or battery 36. Diaphragm 32 is coupled to a resilient spring element shown diagrammatically at 56 which operatively connects an on/off switch 58. Switch 58 is normally open until diaphragm 32 is pressed against the subject. Pressure on diaphragm 32 causes the spring element to flex and close switch 58 establishing electrical power connection between the Gunn diode and electrical circuits and the battery power source. To this end, switch 58 has one end connected by conductor 60 to the positive terminal of the power source 36 and its other end connected by suitable conductors 61 to chip 54 and diode 12. A common ground may be established through the use of a metal case or an internal metal band 62 within the case. Alternatively, the internal surface of the case may be provided with suitable conductive strips formed by thin layers deposited by conventional laminating processes.
Referring now to FIG. 6, there is shown a typical laboratory set up for monitoring cardiac activity of a mouse. Test results were obtained using an ICR mouse 64, female, adult weighing approximately 30 grams. The output detector 28 which may be a point contact Shottky diode is connected via shielded cable 65 to a AC amplifier stage 66 having a gain of 10 4 -10 6 .
Amplifier stage 66 may include one or more conventional stages. Additionally, pre-amplifiers may be included. Conventional IC components may be utilized such as National Semiconductor quad op-amp 4 stage amplifier LM324N and National Semiconductor LM381AN pre-amplifier. The output of the amplifier 66 is coupled via conductor 67 to a oscilloscope 68 and a polygraph recorder 70 (Grass 7WC12PA) for making permanent recordings. An audio output is provided by connecting the output of amplifier 66 to an amplitude to frequency converter 72 which in turn has its output connected to head phones 74 via conductor 73.
FIG. 7 illustrates a typical arrangement for achieving an audible response from backscattered radiation due to biophysical activity of a subject. The output of the Gunn diode is AC coupled to amplifier 66 to remove any DC components. The output of amplifier 66 provides a sub-audible signal which is applied via line 71 to base electrode input of transistor 76. Transistor 76 has its collector/emitter electrodes connected across an RC timing control loop comprising resistors 77 and 78 and capacitor 79. Resistors 77 and 78 are selectively connected into the circuit depending on the position of switch 80. Depending on which resistor is selected establishes whether breathing or lung sounds are filtered or incorporated into the output signal. Lung sounds appear as background noise and conventionally in a stethoscope the heartbeat is heard with the background breathing noise. In the present invention, by switching in a lower value resistance, the sounds due to slow voltage variations occasioned by breathing ##EQU1## are effectively filtered out. The RC network sets the dc input level to the oscillator 82 which is a conventional 1000 cycle voltage controlled oscillator having its audio output connected to phones 74. Variations of the sub-audible input are thus translated into varying tone signals. Advantageously, a conventional squelch arrangement may be provided at the output of the oscillator to avoid low level noise in the phones.
The basic principle of operation consists of the fact that both the heart and the brain modulate an incoming continuous wave microwave signal; and that this modulation appears in the scattered beam. The scattered beam carries information imposed on it by the organ activity.
This modulated scattered wave is detected with a simple diode detector and converted into an identically modulated electric signal. The continuous component of the electric signal is removed by filtering while the sub-audible low frequency modulated signal components (up to approximately 100 Hz) are amplified, and monitored or displayed either on an oscillograph, or a chart recorder, or by conversion to an audio signal. Since these signals represent information imposed on the microwave radiation by the organ, they therefore reflect the operation of that organ.
This phenomenon provides a new technique for probing the physiologic activity, the anatomical structure, and the pathology of the various organs of living animals and man. At the present time, the mechanism for the modulation by the organ of the microwave radiation is not well understood. It was thought to reflect changes induced by mechanical activities of the various organs, but experiments tend to indicate the response may be due in part to electrical activity. Although the mechanism for modulation is not completely understood, nevertheless, with this new technique, it is exceedingly easy to obtain significant information regarding the activity of the heart. The modulation signals are rich and complicated, consisting of many peaks and valleys of different amplitudes and halfwidths. It is obvious that these signals contain a significantly larger quantity of information concerning heart activity than does the standard EKG. There is no apparent dead time in these signals. Because of the ease with which these signals can be obtained from a simple apparatus, they lend themselves well to utility in the medical field of cardiology. By scanning manipulations of the probe over the heart area, these signals may be used to present a visual image of various areas of the heart on an oscilloscope screen. Such an instrument would provide the cardiologist with a totally new capacity for examination of the heart function in animal and human patients for the detection of pathologic conditions.
The basic method was shown to work on mice. The mouse was anesthetized with an injection of sodium pentobarbital (1 cc, 40 mg/kg, injected subcutaneously under the skin of the back). The anesthetic was administered to make the animal tractable for the experiments, and is not necessary for the effect. The mouse is then turned on its back as shown in FIG. 6 and the microprobe positioned above the chest in contact with the skin. Skin contact enhances the strength of the signal and may either eliminate an additional source of extraneous reflected power from the air-skin interface, or provide a better impedance match for power transfer. The microwave power is turned on, and the electrical signal from the detector 28 is coupled to the solid state amplifier 66 of approximately 1000 gain. The input and output of the amplifier are both AC coupled. This removes the DC component.
The band width of the amplifier is approximately 1000 Hz. The output of the amplifier was fed into a Grass Polygraph Recorder. In FIG. 8, there are presented a series of recordings taken on the Grass Polygraph Recorder used in a single channel mode. Each of the recordings is from a slightly different position on the chest. The chart speed is 25 mm/sec. The heart signals recorded can be obtained only from a region of roughly 1/2 cm 2 , centered over the animal's heart. The signals consist of two different types. The first are the signals A appearing approximately once per second and are of high amplitude. These reflect the breathing mode of the animal. The pulses B that appear at approximately five per second are the heart beats of the animal. It can be seen that the modulated microwave signal for the heart beat consists of at least six, and possibly more, peaks and trough; that the shape of these modulated signals change with the position over the chest; and finally, that the signal strength is extremely high since the gain of the Grass Polygraph Recorder was set at 1 mv/cm. The signals change when the microprobe is moved away from the region of the heart, and, at a sufficient distance away, the microprobe can only pick up the signals due to the breathing mode, and the heart pulses have disappeared, as shown in the recording taken over the abdomen.
Referring to FIG. 9, the chest of a mouse was graphed with a 6 mm square of 1 mm blocks, `0-0` refers to a position directly over the heart. The numbers, +2, +4, and +6, -2, -4, and -6, refer to successive 2 mm movements up and down, respectively, from the reference position 0,0. The graphs of FIG. 10 show the change in the nature of the signals as one scans a small portion of the animal's body around the mouse heart with a microprobe.
FIG. 11 shows a chart recording of modulated signals derived by the present invention from a human heart at three different positions. The variations suggest the localizability of the beam and the mapping capacity of the system. It is obvious that the human microwave cardiogram is far more complex than the standard electrocardiogram shown in the upper left hand corner of the recording. A significantly larger amount of information is embodied in the modulated microwave heart beat signal than is present in the EKG and the apparatus allows one to examine the physiologic activity of the heart in a living animal with minimal irritation and to obtain a rich supply of information that is presently beyond the capacity of the EKG and other known instruments.
A further development consists of a Stereophonic diagnostic instrument. By the use of two independent microprobes whose separation distance and angular orientations are selectively varied, there is provided a three-dimensional sound picture of the heart activity. The output of each microprobe is fed into one channel of a stereo amplifier, the output of which goes to one loudspeaker or channel of a stero amplifier, the output of which goes to one loudspeaker or headphone.
Another application is in microwave cardiography. As demonstrated above, the output of the diode can be fed directly to a chart recording for a permanent record. The resulting signal is a complex composed of a number of peaks of varying amplitudes and halfwidths. By comparing normal hearts with abnormal hearts, a determination of pathologic conditions of the heart by simple examination of the chart can be made. Also, the microprobe can be placed serially at different positions around the heart region of the chest to obtain additional information due to the different geometry; or the microprobe can be mechanically or electrically moved in a scanning pattern across the surface of the chest to provide additional information. Variations in the shape of the modulated signals with geometry can provide further information on the localization of abnormalities.
From any single microprobe in a given position over the chest cavity there is a time varying signal reflecting the microwave modulating activity of the heart. It is possible, by a number of known means, to convert this modulated signal into a visual display of the heart in actual real time movement.
For example, an array of microwave sources and detectors can be electrically scanned in a timed sequence and the outputs presented to the intensity control of a synchronously scanned oscilloscope beam. The time for one complete scan must be short compared to the movement time of the heart. This, then, provides a rough two-dimensional picture in time of the heart movement. An alternative embodiment would be to have the microprobe movement rapidly scanning the chest cavity in synchrony with the oscilloscope beam. The microwave beam may also be converted from a continuous wave to a pulsed beam, with the pulse frequency sufficiently high so that the scanning beam time for one frame would give a good resolution. The parameters are not too dissimilar to a vidicon television system.
As hereinbefore noted, modulation due to heart activity has generally been thought to be the results of mechanical muscle movement. However, experiments in connection with microwaves scattered from the heads and spinal cords, contain modulations in amplitude which reflect on going biological activity in these organs and which suggest the response is due to neural activity and interaction on the input beam.
The animals used in the detection of brain activity are the ICR mouse, female, adult, weighing approximately 30 grams, and the Dutch belted rabbit, female, adult, weighing approximately 1 kilogram. The animals were anesthetized with sodium pentobarbital to put them in the dormant state. The animals were then mounted in a stereotaxic holder made of wood and glass to minimize disturbance of the microwaves. These heads are rigidly restrained. The microprobe is placed on the dorsal surface of the head of the anesthetized animal. The probe need not make direct contact with the skin for signals to be obtained. In some cases the animal's fur was shaved, and, in one case, the skin of the surface of the head was resected to expose the skull. In this latter case the same signals were obtained, thus removing the possibility that skin or muscle movements are the source of the signals.
The modulated signals consist of a variety of types, differing in frequencies, amplitudes and wave forms. The dominant form of activity sensed by the microprobe is the lowest frequency range, between 0.5 and 2 hertz. These signals are rhythmic pulsations which are closely associated with the animal's respiration. These signals may be monophasic, or, as is more usual, biphasic. These types of signals are called "breathing modes". In some cases they appear to be sharp, with a full width at half maximum, of about 0.1 seconds; in other cases the width can be 3 to 4 times larger. A second type of signal found in the rabbit, related to these "breathing mode" spikes are those resembling alpha wave spindles. These are at a frequency of 8 hertz, while interspindle spikes occur at a frequency of about 16 hertz. Similar signals in the mouse do not appear to be related to the "breathing modes". The high frequency cutoff of the polygraph eliminated possible higher frequency components.
With either a dead animal, or one in a deeply anesthetized state (though still breathing) no signals are detected. As the anesthetic wears off (though the animals are still torpid) the signals emerge from the background noise thus monitoring the depth of anesthesia. These signals are shown in FIG. 12 as recorded by an array of 7 different, but roughly matched, diodes arranged in a semicircle above the head, from left to right. The microwave beam entered frontally at a 90° angle to the array. These, and other data, illustrate that the "breathing mode" is not distributed uniformly across the head. The spatial distribution varies smoothly as a function of position of the diode array. Bilateral asymmetry is often observed. The "breathing mode" is variable in time at a given position, i.e. particular positions alternately pulsated and then became silent for a period of many minutes. The wave form also can appear in a mirror image of itself in various places on the cranium at different times.
The confirmation that these microwave signals reflect electrical activity of the brain is the appearance of evoked responses. Such signals have appeared in both the mouse and the rabbit using a variable frequency light source. A light emitting diode was chosen whose light was in the yellow spectral region. The frequency was controlled by applying a sinusoidal voltage to it from an Ando ULO-5 oscillator. To avoid electrical interference with the microprobe, the light from the diode was conducted via a 30 cm. glass rod to the eye of the dark adapted animal. The microwave semiconducting diode detector was shown to be insensitive to visible light, and, in any case, a black cloth covered the head of the animal, preventing the light from reaching the diode. On a number of occasions, a change in the microwave signals when the stimulus was applied has been observed. A recording, clearly showing an entrainment of the microprobe signals with the light signals, is shown in FIG. 13. These recordings were obtained from the occipital regions of the head.
The microprobe of the invention has also been used to probe the spinal cord of both the mouse and the rabbit and the resultant modulated signals obtained are illustrated in FIG. 14. Movement of the microprobe a few millimeters away from the spine in either direction causes a loss of these signals. These signals contain the "breathing mode" pattern with a superimposed spike frequency at 6 hertz, plus smaller amplitude, but higher frequency spikes at 16 hertz. For purposes of comparison, it is noted that the heart beat rate as determined by the probe over the animal's chest was 4-5 hertz for the mouse and 3-4 hertz for the rabbit. Thus, neither the brain nor the spinal cord signals can easily be attributed to the heart movement, or to coordinated blood pressure waves.
The simplest assumption to make is to attribute the signals we have reported here to purely mechanical movements, but it has become difficult to sustain this argument. The fact that the signal strength is a function of the depth of anesthesia, and does not appear in a deeply anesthetized animal which is still breathing, cannot easily be reconciled with purely mechanical movements. The plasticity of the signals, both with position and time, the changes in wave form, and the evident asymmetry across the head, further increase our doubts. The appearance of evoked response activity suggests more than a purely mechanical source for these signals. We, therefore, believe that it is at least possible that some, if not all, of these microprobe signals reflect, either directly or indirectly, underlying electrical activity of the brain and spinal cord. | A portable microprobe uses 10 gigahertz CW microwave radiation at a power level of less than 10 milliwatts for recording of a number of biophysical phenomena associated with the cardiac and neural activity of the life system. The microprobe consists of a Gunn diode feeding power into a short, insulated dielectric waveguide, the free end of which houses a point contact semiconductor diode isolated by a metal shield from the incident beam. The wave guide concentrates and delivers a pencil shaped beam into the tissue of interest and the back-scattered radiation is modulated and detected by the diode. The detected signal is filtered, amplified and recorded to reflect on-going biological activity. The receiver electronics is housed in a small self-contained package and has its output connected through a flexible attachment to two ear tubes which enable continuous monitoring of the audio response through an electrical and audio converter indicative of the on-going biological activity. By scanning step wise across the chest, the microprobe allows localization of many details of cardiac activity. The microprobe can also be used to monitor activities of the brain and the spinal cord. | 34,353 |
FIELD OF THE INVENTION
[0001] The present invention relates to a wireless relay TDD (Time Division Duplexing) system, especially to a relay station (RS), a base station (BS) and a mobile terminal (MT) in a wireless relay TDD system.
BACKGROUND OF THE INVENTION
[0002] Currently, RS (Relay Station) has been introduced into IMT-Advanced system for extending the network coverage and enhancing the transmission efficiency. The possibility of implementing RS dual-direction receiving and transmission in different sub-carriers is proposed in the proposals of 3GPP R1-090665 and 3GPP R1-090734. However, no matter whether the proposal that RS implements dual-direction communication can be adopted, how RS satisfies the synchronization requirements with MT (Mobile Terminal) and eNB (evolved Node B) at the same time at the switching point of transmitting/receiving or receiving/transmitting is an urgent issue to be resolved.
[0003] In prior art, the eNB and RS may employ two kinds of synchronization, that is, GPS (Global Positioning System) and AI (Air Interface) synchronization. FIG. 1 and FIG. 2 show the schematic diagrams of the occurred interference problems of the eNB and RS under synchronization of GPS and synchronization of AI respectively. It is to be noted that, the interference problems are described in FIG. 1 and FIG. 2 by taking the frame structure of configuration 1 proposed in 3GPP TS36.211, v8.5.0 as an example, and without loss of generality, other frame structures in TDD system have the same interference problem as well.
[0004] Referring to FIG. 1 and FIG. 2 , assuming that the third sub-frame is the backhaul from RS to eNB, and the eighth sub-frame is the backhaul from eNB to RS. Here, the eighth sub-frame is “stolen UL”, that is, in the frame structure defined in TDD system, originally the eighth sub-frame should be an uplink sub-frame, but now it is used as a downlink sub-frame. It is to be noted that the eighth sub-frame here acting as a downlink sub-frame is only for embodying all of the possibly occurred problems in the same frame. In practical application, the eighth sub-frame may still act as an uplink sub-frame.
[0005] Usually, because the distance between eNB and RS is relative long, there will be transmission latency in the data transmission between eNB and RS. Assuming that the distance between eNB and RS is r, the transmission latency between eNB and RS is r/c, wherein, c is velocity of light. The transmission latency between MT and RS may be neglected because the distance between MT and RS is relative short.
[0006] As shown in FIG. 1 , for a RS, only after it finishes receiving the second sub-frame from MT, can it send the third sub-frame to the eNB. Because there is transmission latency from the RS to the eNB, the eNB has to send the fourth sub-frame to the RS before completely finishing receiving the third sub-frame from the RS. Therefore, the eNB can only receive part of data of the third sub-frame from the RS and has to give up receiving other data. If the length (namely the latency from the RS to the eNB) of data which the eNB gives up to receive is greater than CP (Cyclic Prefix), then the eNB can not completely recover the content of the third sub-frame from the RS.
[0007] Similarly, for the reason of transmission latency from the eNB to the RS, the RS has to send the ninth sub-frame to the MT before completely finishing receiving the eighth sub-frame from the eNB. Therefore the RS can only receive part of data of the eighth sub-frame from the eNB and has to give up receiving other data, thereby it may cause that the RS can not completely recover the content of the eighth sub-frame from the eNB.
[0008] Because the eNB and the RS are under synchronization of AI in FIG. 2 , there is no interference problem between the eighth sub-frame and the ninth sub-frame, however, it may be seen from FIG. 2 that the interference problem between the third sub-frame and the fourth sub-frame is more serious than that under synchronization of GPS.
SUMMARY OF THE INVENTION
[0009] In order to solve the aforesaid disadvantages in the prior art, the present invention proposes a method and device for eliminating interference in a wireless relay TDD system, particularly, by reducing the GP (Guard Period) of a relay station by a predetermined time length and performing data receiving and data sending by using the reduced predetermined time length, interference caused by non-synchronization between an eNB and a RS is avoided.
[0010] According to the first aspect of the present invention, there is provided a method of eliminating interference in a wireless relay TDD system, wherein, the method comprises the step of: reducing the GP of a relay station by a predetermined time length and performing data receiving and data sending by using the reduced predetermined time length.
[0011] According to the second aspect of the present invention, there is provided a method of eliminating interference in a relay station of a wireless relay TDD system, wherein, the method comprises the step of: reducing the GP of a relay station by a predetermined time length and performing data receiving and data sending by using the reduced predetermined time length.
[0012] According to the third aspect of the present invention, there is provided a method of assisting a relay station to eliminate interference in a base station of a wireless relay TDD system, wherein, the method comprises the step of assisting the relay station that uses the method according to the aforesaid second aspect, to perform data receiving and sending.
[0013] According to the fourth aspect of the present invention, there is provided an interference eliminating device for eliminating interference in a wireless relay TDD system, wherein, the interference eliminating device is used for reducing the GP of a relay station by a predetermined time length and performing data receiving and data sending by using the reduced predetermined time length.
[0014] According to the fifth aspect of the present invention, there is provided an assisting interference eliminating device, for assisting a relay station to eliminate interference in a base station of a wireless relay TDD system, wherein, the assisting interference eliminating device is used for assisting the relay station that uses the interference eliminating device according to the aforesaid fourth aspect, to perform data receiving and sending.
[0015] By using the technical solution of the present invention, interference caused due to non-synchronization between an eNB and a RS may be avoided.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] By reading the detailed description of the non-limiting embodiments with reference to the following drawings, other features, objects and advantages of the present invention will become apparent:
[0017] FIG. 1 shows a schematic diagram of the occurred interference problems of the eNB and RS under synchronization of GPS in the prior art;
[0018] FIG. 2 shows a schematic diagram of the occurred interference problems of the eNB and RS under synchronization of AI in the prior art;
[0019] FIG. 3 shows a schematic diagram of the frame structure of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of GPS, according to a first embodiment of the present invention;
[0020] FIG. 4 shows a flowchart of system method of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of GPS, according to a first embodiment of the present invention;
[0021] FIG. 5 shows a schematic diagram of the frame structure of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of GPS, according to a second embodiment of the present invention;
[0022] FIG. 6 shows a flowchart of system method of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of GPS, according to a second embodiment of the present invention;
[0023] FIG. 7 shows a schematic diagram of the frame structure of eliminating interference by occupying the resource of the GP for data transmission when the eNB and RS are under synchronization of GPS, according to a third embodiment of the present invention;
[0024] FIG. 8 shows a flowchart of system method of eliminating interference by occupying the resource of the GP for data transmission when the eNB and RS are under synchronization of GPS, according to a third embodiment of the present invention;
[0025] FIG. 9 shows a schematic diagram of the frame structure of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of AI, according to a fourth embodiment of the present invention;
[0026] FIG. 10 shows a flowchart of system method of eliminating interference by reducing the length of the OP when the eNB and RS are under synchronization of AI, according to a fourth embodiment of the present invention;
[0027] FIG. 11 shows a block diagram of system structure of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of GPS, according to a fifth embodiment of the present invention;
[0028] FIG. 12 shows a block diagram of system structure of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of GPS, according to a sixth embodiment of the present invention;
[0029] FIG. 13 shows a block diagram of system structure of eliminating interference by occupying the resource of the GP for data transmission when the eNB and RS are under synchronization of GPS, according to a seventh embodiment of the present invention; and
[0030] FIG. 14 shows a block diagram of system structure of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of AI, according to an eighth embodiment of the present invention;
[0031] In drawings, same or similar reference signs refer to the same or similar component.
DETAILED DESCRIPTION OF EMBODIMENTS
[0032] In the followings, the present invention is described in detail with reference to the drawings.
[0033] Usually, because RS cell is smaller than eNB cell, it is feasible for RS to use a shorter GP compared with eNB.
[0034] Preferably, the GP for RS may be half of the GP for eNB. Even if RS only uses half of the GP for eNB, it is enough for RS, since half the GP means:
[0035] 1) the adius of RS cell is at least 10 km;
[0036] 2) the RS's transmission power is only about 6 dB lower than the eNB's transmission power;
[0037] 3) the RS cell can cover from the eNB to the cell edge if the RS is located at the middle position of the eNB and the cell edge;
[0038] 4) the RS cell can cover the middle point between the eNB and the RS if the RS is located at the cell edge.
[0039] Certainly, the GP for RS may be reduced to a value that is smaller than half of the GP for eNB, but it will not influence the essence of the technical solution of the present invention.
[0040] Hereinafter, reducing the GP for RS to half of the GP for eNB is taken as example to describe the technical solution of the present invention.
[0041] At the same time, hereinafter, the magnitude of transmission latency between the eNB and the RS being equal to half of the magnitude of the GP for eNB (that is, the magnitude of transmission latency between the eNB and the RS is equal to the magnitude of the reduced GP for RS, GP/2) is taken as example to describe the present invention.
Embodiment 1
[0042] The embodiment is for the scenario that the eNB 2 and the RS 1 are under synchronization of GPS and the RS 1 sends the third sub-frame to the eNB 2 after finishing receiving the second sub-frame from the MT 0 .
[0043] FIG. 3 shows a schematic diagram of the frame structure of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of GPS, according to a first embodiment of the present invention.
[0044] FIG. 4 shows a flowchart of method of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of GPS, according to a first embodiment of the present invention.
[0045] In FIG. 3 , the 0 th sub-frame is a downlink sub-frame, the first sub-frame is a special sub-frame, the second sub-frame is an uplink sub-frame, the third sub-frame is an uplink sub-frame, and the fourth sub-frame is a downlink sub-frame. Wherein, Dw (DwPTS) in the second sub-frame is downlink synchronization time slot, G (GP) is guard period, and Up (UpPTS) is uplink synchronization time slot.
[0046] Comparing FIG. 2 with FIG. 3 , it can be seen that the eNB 3 may completely finish receiving the third sub-frame from RS before starting to send the fourth sub-frame by reducing the GP of the RS 1 to half of the GP of the eNB 2 in this embodiment.
[0047] After the MT 0 starts up, firstly downlink synchronization should be established with cell, and then uplink synchronization can be started to establish. How the MT 0 establishes downlink synchronization is the prior art, and those skilled in the art should understand it, which will not be described in detail for the purpose of simplicity.
[0048] In the present invention, the process of the MT 0 establishing uplink synchronization with the RS 1 is the same as that in the prior art, and the only difference is that, after the MT 0 sends uplink synchronization code to the RS 1 , information of timing advancing comprised in the uplink timing advancing signaling that is fed back to the MT 0 by the RS 1 will change, namely, the RS 1 will add original GP/2 timing advancing to original timing advancing. That is to say, the moment at which the MT 0 starts to send uplink sub-frames will be ahead of the moment indicated by original timing advancing by GP/2.
[0049] To be specific, the MT 0 firstly sends the uplink synchronization code to the RS 1 at UpPTS time slot when the MT 0 performs random access. After the RS 1 receives the uplink synchronization code from the MT 0 , it sends the uplink timing advancing signaling to the MT 0 in the step S 11 . Wherein, the uplink timing advancing signaling comprises information of timing advancing, and in the present invention, the information of timing advancing equals to the original timing advancing plus GP/2 timing advancing. Then, in the step S 12 , the MT 0 receives uplink timing advancing signaling from RS 1 , and the MT 0 may know when it should send uplink sub-frames to reach uplink synchronization with the RS 1 according to information of timing advancing comprised in the uplink timing advancing signaling.
[0050] Because the RS 1 adds GP/2 timing advancing to the original timing advancing, in the step S 13 , the MT 0 sends the second sub-frame (that is, the uplink sub-frame from the MT 0 to the RS 1 ) to the RS 1 ahead of the original sending moment of the second sub-frame by GP/2.
[0051] Then, in the step S 14 , the RS 1 starts to receive the second sub-frame from the MT 0 ahead of the original receiving moment by GP/2. Because the MT 0 starts to send the second sub-frame to the RS 1 ahead of time by GP/2, the RS 1 finishes receiving the second sub-frame from the MT 0 ahead of time by GP/2.
[0052] Because the RS 1 finishes receiving the second sub-frame ahead of time by GP/2, and accordingly, in the step S 15 , the RS 1 starts to send the third sub-frame (that is, the uplink sub-frame from the RS 1 to the eNB 2 ) to the eNB 2 ahead of time by GP/2.
[0053] After that, in the step S 16 , the eNB 2 receives the third sub-frame from the RS 1 .
[0054] Considering that the transmission latency from the RS 1 to the eNB 2 is GP/2, and the RS 1 sends the third sub-frame ahead of the original sending moment by therefore, as shown in FIG. 3 , the eNB 2 completely finishes receiving the third sub-frame from the RS 1 before starting to send the fourth sub-frame to the RS 1 so that the receiving of the third sub-frame and the sending of the fourth sub-frame of the eNB 2 will not cause interference.
[0055] Certainly, while the RS 1 sends the third sub-frame to the eNB 2 , the RS 1 may also sends downlink data to the MT 0 using other frequency bands.
Embodiment 2
[0056] The embodiment is for the scenario that the eNB 2 and the RS 1 are under synchronization of GPS and the RS 1 sends the ninth sub-frame to the MT 0 after finishing receiving the eighth sub-frame from the eNB 2 . And, in the embodiment, the frequency band occupied by the data transmission between the eNB 2 and the RS 1 is different from the frequency band occupied by the data transmission between the MT 0 and the RS 1 .
[0057] FIG. 5 shows a schematic diagram of the frame structure of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of GPS, according to a second embodiment of the present invention.
[0058] FIG. 6 shows a flowchart of method of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of GPS, according to a second embodiment of the present invention.
[0059] For the purpose of simplicity, the frequency band used for the data transmission between the eNB 2 and the RS 1 is called as the frequency band from the eNB 2 to the RS 1 ; the frequency band used for the data transmission between the MT 0 and the RS 1 is called as the frequency band from the MT 0 to the RS 1 .
[0060] Similar to the embodiment 1, after the MT 0 receives the uplink timing advancing signaling from the RS 1 (corresponding to the step S 21 and the step S 22 in FIG. 6 respectively), in the step S 23 , the MT 0 sends uplink data to the RS 1 in the frequency band from the MT 0 to the RS 1 (in FIG. 5 , denoted by “ ”) ahead of time by GP/2. Because the MT 0 sends uplink data to the RS 1 ahead of time by GP/2, accordingly, in the step S 24 , the RS 1 receives uplink data from the MT 0 in the frequency band from the MT 0 to the RS 1 ahead of time by GP/2.
[0061] At the same time, because the MT 0 finishes sending uplink data to the RS 1 ahead of time by GP/2, part of time-frequency resources of the MT 0 for sending uplink data become idle.
[0062] Because this part of time-frequency resources become idle, in the step S 25 , the eNB 2 sends to the RS 1 a first data block corresponding to GP/2 time length in the eighth sub-frame in the frequency band from the MT 0 to the RS 1 , and sends to the RS 1 the remaining second data block in the eighth sub-frame in a frequency band from the eNB 2 to the RS 1 (in FIG. 5 , denoted by “ ”).
[0063] Preferably, the first data block intercepted from the eighth sub-frame comprises a reference symbol, in such a way that the RS 1 can estimate the channel state from the MT 0 to the RS 1 after receiving the first data block. Certainly, if the first data block intercepted from the eighth sub-frame does not comprise a reference symbol, the eNB 2 may firstly add the reference symbol into the first data block before sending the first data block, in such a way that the RS 1 can estimate the channel state from the MT 0 to the RS 1 after receiving the first data block.
[0064] It is to be noted, the first data block intercepted from the eighth sub-frame should be sent within a specific time slot so that the RS 1 can just receive the first data block on a time frequency resource that becomes idle after the MT 0 finishes sending the uplink data ahead of time by GP/2.
[0065] Then, in the step S 26 , the RS 1 receives the first data block on a time frequency resource that becomes idle after the MT 0 finishes sending the uplink data ahead of time by GP/2, and receives a second data block in the frequency band from the eNB 2 to the RS 1 . After then, the two parts of data blocks are merged to get the eighth sub-frame from the eNB 2 .
[0066] Because the first data block in the eighth sub-frame is sent to the RS 1 using the frequency band from the MT 0 to the RS 1 , as shown in FIG. 5 , the RS 1 has already finished receiving the eighth sub-frame from the eNB 2 before starting to send the ninth sub-frame to the MT 0 so that the receiving of the eighth sub-frame and the sending of the ninth sub-frame of the RS 1 will not cause interference.
Embodiment 3
[0067] The embodiment is for the scenario that the eNB 2 and the RS 1 are under synchronization of GPS and the RS 1 sends the ninth sub-frame to the MT 0 after finishing receiving the eighth sub-frame from the eNB 2 . And, in the embodiment, the frequency band occupied by the data transmission between the eNB 2 and the RS 1 is the same as the frequency band occupied by the data transmission between the MT 0 and the RS 1 .
[0068] FIG. 7 shows a schematic diagram of the frame structure of eliminating interference by occupying the resource of the GP for data transmission when the eNB and RS are under synchronization of GPS, according to a third embodiment of the present invention;
[0069] FIG. 8 shows a flowchart of system method of eliminating interference by occupying the resource of the GP for data transmission when the eNB and RS are under synchronization of GPS, according to a third embodiment of the present invention;
[0070] In FIG. 7 , the fifth sub-frame is a downlink sub-frame, the sixth sub-frame is a special sub-frame, the seventh sub-frame is an uplink sub-frame, the eighth sub-frame is an uplink sub-frame, and the ninth sub-frame is a downlink sub-frame. Wherein, Dw (DwPTS) in the sixth sub-frame is downlink synchronization time slot, G (GP) is guard period, and Up (UpPTS) is uplink synchronization time slot.
[0071] As shown in FIG. 7 , in the embodiment, assuming that the eighth sub-fra “stolen UL”, which is taken as downlink sub-frame. That is, the eNB 2 sends the eighth sub-frame to the RS 1 , and the RS 1 sends the ninth sub-frame to the MT 0 after finishing receiving the eighth sub-frame from the eNB 2 .
[0072] Because there is transmission latency in the data transmission from the eNB 2 to the RS 1 , the RS 1 does not finish receiving the eighth sub-frame from the eNB 2 while preparing to send the ninth sub-frame to the MT 0 . Based on this, the eNB 2 sends part of data of the eighth sub-frame within the GP of specific sub-frame (the sixth sub-frame) in advance, and sends the remaining data of the eighth sub-frame by still using the original time frequency resources. In this way, the RS 1 just starts to send the ninth sub-frame to the MT 0 after finishing receiving the eighth sub-frame from the eNB 2 .
[0073] To be specific, in the step S 31 , the eNB 2 sends to the RS 1 a first data block corresponding to GP/2 time length in the eighth sub-frame via the frequency band from the eNB 2 to the RS 1 within the GP of specific sub-frame.
[0074] Accordingly, considering the transmission latency from the eNB 2 to the RS 1 , in the step S 32 , the RS 1 receives the first data block from the eNB 2 within the specific time slot of GP.
[0075] Preferably, as shown in FIG. 7 , the RS 1 starts to receive the first data block from the eNB 2 at the GP/4 after the starting moment of GP, and finishes receiving the first data block from the eNB 2 at the GP/4 before the end moment of GP.
[0076] Based on this, considering the transmission latency of GP/2 from the eNB 2 to the RS 1 , in order to enable the RS 1 to receive the first data block from the eNB 2 within the specific time slot of GP, the eNB 2 should start to send the first data block to the RS 1 at the last GP/4 of DwPTS time slot.
[0077] It is to be noted, usually, the downlink synchronous signal sent within DwPTS time slot only occupies the very narrow frequency band, which is different from the frequency band occupied by the downlink data transmission from the eNB 2 to the RS 1 , therefore, even if the eNB 2 starts to send the first data block to the RS 1 from the last GP/4 of the DwPTS time slot, it will not cause interference with that the eNB 2 sends the downlink synchronous signal within DwPTS time slot.
[0078] Certainly, the RS 1 may also start to receive the first data block from the eNB 2 at the starting time of GP, and accordingly, the eNB 2 needs to start to send the first data block to the RS 1 at the GP/2 before the starting time of GP.
Embodiment 4
[0079] The embodiment is for the scenario that the eNB 2 and the RS 1 are under synchronization of AI and the RS 1 sends the third sub-frame to the eNB 2 after finishing receiving the second sub-frame from the MT 0 . And, in the embodiment, the frequency band occupied by the data transmission between the eNB 2 and the RS 1 is different from the frequency band occupied by the data transmission between the MT 0 and the RS 1 .
[0080] FIG. 9 shows a schematic diagram of the frame structure of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of AI, according to a fourth embodiment of the present invention;
[0081] FIG. 10 shows a flowchart of method of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of AI, according to a fourth embodiment of the present invention;
[0082] For the purpose of simplicity, the frequency band used for the data transmission between the eNB 2 and the RS 1 is called as the frequency band from the eNB 2 to the RS 1 ; the frequency band used for the data transmission between the MT 0 and the RS 1 is called as the frequency band from the MT 0 to the RS 1 .
[0083] Because the eNB 2 and the RS 1 are under synchronization of AI, therefore, referring to FIG. 2 , there is no interference between the eighth sub-frame and the ninth sub-frame, but the interference between the third sub-frame and the fourth sub-frame is more serious.
[0084] Similar to the embodiment 1, the MT 0 firstly sends the uplink synchronization code to the RS 1 at UpPTS time slot when the MT 0 performs random access. After the RS 1 receives the uplink synchronization code from the MT 0 , it sends the uplink timing advancing signaling to the MT 0 in the step S 41 . Wherein, the uplink timing advancing signaling comprises information of timing advancing, and in the present invention, the information of timing advancing equals to the original timing advancing plus GP/2 timing advancing. Then, in the step S 42 , the MT 0 receives uplink timing advancing signaling from RS 1 , and the MT 0 may know when it should send uplink sub-frames to reach uplink synchronization with the RS 1 according to information of timing advancing comprised in the uplink timing advancing signaling.
[0085] Because the RS 1 adds GP/2 timing advancing to the original timing advancing, in the step S 43 , the MT 0 sends the second sub-frame (that is, the uplink sub-frame from the MT 0 to the RS 1 ) to the RS 1 ahead of the original sending moment by GP/2.
[0086] Then, in the step S 44 , the RS 1 starts to receive the second sub-frame from the MT 0 ahead of the original receiving moment by GP/2. Because the MT 0 starts to send the second sub-frame to the RS 1 ahead of time by GP/2, the RS 1 finishes receiving the second sub-frame from the MT 0 ahead of time by GP/2. Because the RS 1 finishes receiving the second sub-frame ahead of time by GP/2, accordingly, the RS 1 starts to send the third sub-frame (that is, the uplink sub-frame from the RS 1 to the eNB 2 ) to the eNB 2 ahead of time by GP/2.
[0087] Because the MT 0 finishes sending uplink data to the RS 1 ahead of time by GP/2, part of time-frequency resources of the MT 0 for sending uplink data become idle.
[0088] Based on this, in the step S 45 , the RS 1 sends to the eNB 2 a first data block corresponding to GP/2 time length in the third sub-frame on the time frequency resource that becomes idle after the MT 0 finishes sending the uplink data ahead of time by GP/2, and at the same time sends to the eNB 2 the remaining second data block in the third sub-frame ahead of time by GP/2 in the frequency band from the RS 1 to the eNB 2 .
[0089] Then, in the step S 46 , the eNB 2 receives the first data block from the RS 1 in the frequency band from the MT 0 to the RS 1 , and receives the second data block from the RS 1 in the frequency band from the RS 1 to the eNB 2 .
[0090] After the eNB 2 receives the first data block and the second data block on the different frequency bands, the two parts of data blocks are merged to get the third sub-frame from the RS 1 .
[0091] In a variation, if the frequency band occupied by the data transmission between the eNB 2 and the RS 1 is the same as the frequency band occupied by the data transmission between the MT 0 and the RS 1 , the RS 1 may send the first data block by only using the time frequency resource that becomes idle after the MT 0 finishes sending the uplink data ahead of time by GP/2. Based on this, the data block of (2P-GP/2) time length in the third sub-frame which is sent to the eNB 2 by the RS 1 is discarded, wherein P is the latency time of transmission from the RS 1 to the eNB 2 . If the latency time of transmission from the RS 1 to the eNB 2 is GP/2, a data block of GP/2 time length in the third sub-frame which is sent to the eNB 2 by the RS 1 is discarded.
[0092] Hereinbefore, the technical solution of the present invention is described from the aspect of method; hereinafter, the technical solution of the present invention will be further described from the aspect of device module.
Embodiment 5
[0093] The embodiment is for the scenario that the eNB 2 and the RS 1 are under synchronization of GPS and the RS 1 sends the third sub-frame to the eNB 2 after finishing receiving the second sub-frame from the MT 0 .
[0094] FIG. 11 shows a block diagram of system structure of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of GPS, according to a fifth embodiment of the present invention. The MT 0 , the eNB 2 and an interference eliminating device 11 in the RS 1 are shown in the FIG. 11 , wherein the interference eliminating device 11 comprises a first sending means 111 , a first receiving means 112 and a second sending means 113 .
[0095] In the embodiment, the contents of FIG. 3 are taken as reference here together.
[0096] In FIG. 3 , the 0 th sub-frame is a downlink sub-frame, the first sub-frame is a special sub-frame, the second sub-frame is an uplink sub-frame, the third sub-frame is an uplink sub-frame, and the fourth sub-frame is a downlink sub-frame. Wherein, Dw (DwPTS) in the second sub-frame is downlink synchronization time slot, G (GP) is guard period, and Up (UpPTS) is uplink synchronization time slot.
[0097] Comparing FIG. 2 with FIG. 3 , it can be seen that the eNB 3 may completely finish receiving the third sub-frame from RS before starting to send the fourth sub-frame by reducing the GP of the RS 1 to half of the GP of the eNB 2 in this embodiment.
[0098] After the MT 0 starts up, firstly downlink synchronization should be established with cell, and then uplink synchronization can be started to establish. How the MT 0 establishes downlink synchronization is the prior art, and those skilled in the art should understand it, which will not be described in detail for the purpose of simplicity.
[0099] In the present invention, the process of the MT 0 establishing uplink synchronization with the RS 1 is the same as that in the prior art, and the only difference is that, after the MT 0 sends uplink synchronization code to the RS 1 , information of timing advancing comprised in the uplink timing advancing signaling that is fed back to the MT 0 by the RS 1 will change, namely, the RS 1 will add original GP/2 timing advancing to original timing advancing. That is to say, the moment at which the MT 0 starts to send uplink sub-frames will be ahead of the moment indicated by original timing advancing by GP/2.
[0100] To be specific, the MT 0 firstly sends the uplink synchronization code to the RS 1 at UpPTS time slot when the MT 0 performs random access. After the RS 1 receives the uplink synchronization code from the MT 0 , the first sending means 111 in the interference eliminating device 11 in the RS 1 sends the uplink timing advancing signaling to the MT 0 . Wherein, the uplink timing advancing signaling comprises information of timing advancing, and in the present invention, the information of timing advancing equals to the original timing advancing plus GP/2 ing advancing. Then, the MT 0 receives uplink timing advancing signaling from RS 1 , and the MT 0 may know when it should send uplink sub-frames to reach uplink synchronization with the RS 1 according to information of timing advancing comprised in the uplink timing advancing signaling.
[0101] Because the RS 1 adds GP/2 timing advancing to the original timing advancing, the MT 0 sends the second sub-frame (that is, the uplink sub-frame from the MT 0 to the RS 1 ) to the RS 1 ahead of the original sending moment of the second sub-frame by GP/2.
[0102] The first receiving means 112 in the interference eliminating device 11 in the RS 1 starts to receive the second sub-frame from the MT 0 ahead of the original receiving moment by GP/2. Because the MT 0 starts to send the second sub-frame to the RS 1 ahead of time by GP/2, the first receiving means 112 in the RS 1 finishes receiving the second sub-frame from the MT 0 ahead of time by GP/2.
[0103] Because the first receiving means 112 in the RS 1 finishes receiving the second sub-frame ahead of time by GP/2, and accordingly, the second sending means 113 in the interference eliminating device 11 in the RS 1 starts to send the third sub-frame (that is, the uplink sub-frame from the RS 1 to the eNB 2 ) to the eNB 2 ahead of time by GP/2.
[0104] After that, the eNB 2 receives the third sub-frame from the RS 1 .
[0105] Considering that the transmission latency from the RS 1 to the eNB 2 is GP/2, and second sending means 113 in the RS 1 sends the third sub-frame ahead of the original sending moment by GP/2, therefore, as shown in FIG. 3 , the eNB 2 completely finishes receiving the third sub-frame from the RS 1 before starting to send the fourth sub-frame to the RS 1 so that the receiving of the third sub-frame and the sending of the fourth sub-frame of the eNB 2 will not cause interference.
[0106] Certainly, while the RS 1 sends the third sub-frame to the eNB 2 , the RS 1 may also sends downlink data to the MT 0 using other frequency bands.
Embodiment 6
[0107] The embodiment is for the scenario that the eNB 2 and the RS 1 are under synchronization of GPS and the RS 1 sends the ninth sub-frame to the MT 0 after finishing receiving the eighth sub-frame from the eNB 2 . And, in the embodiment, the frequency band occupied by the data transmission between the eNB 2 and the RS 1 is different from the frequency band occupied by the data transmission between the MT 0 and the RS 1 .
[0108] FIG. 12 shows a block diagram of system structure of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of GPS, according to a sixth embodiment of the present invention. The MT 0 , an interference eliminating device 12 in the RS 1 and an assisting interference eliminating device 22 in the eNB 2 are shown in FIG. 12 , wherein, the interference eliminating device 12 comprises a third sending means 121 , a second receiving means 122 and a third receiving means 123 , and the assisting interference eliminating device 22 comprises a sixth sending means 221 .
[0109] In the embodiment, the contents of FIG. 5 are taken as reference here together.
[0110] For the purpose of simplicity, the frequency band used for the data transmission between the eNB 2 and the RS 1 is called as the frequency band from the eNB 2 to the RS 1 ; the frequency band used for the data transmission between the MT 0 and the RS 1 is called as the frequency band from the NIT 0 to the RS 1 .
[0111] Similar to the embodiment 5, after the MT 0 receives the uplink timing advancing signaling from the third sending means 121 in the interference eliminating device 12 in the RS 1 , the MT 0 sends uplink data to the RS 1 in the frequency band from the MT 0 to the RS 1 (in FIG. 5 , denoted by “ ”) ahead of time by GP/2. Because the MT 0 sends uplink data to the RS 1 ahead of time by GP/2, accordingly, the second receiving means 122 in the interference eliminating device 12 in the RS 1 receives uplink data from the MT 0 in the frequency band from the MT 0 to the RS 1 ahead of time by GP/2.
[0112] At the same time, because the MT 0 finishes sending uplink data to the RS 1 ahead of time by GP/2, part of time-frequency resources of the MT 0 for sending uplink data become idle.
[0113] Because this part of time-frequency resources become idle, the sixth sending means 221 in the assisting interference eliminating device 22 in the eNB 2 sends to the RS 1 a first data block corresponding to GP/2 time length in the eighth sub-frame in the frequency band from the MT 0 to the RS 1 , and sends to the RS 1 the remaining second data block in the eighth sub-frame in a frequency band from the eNB 2 to the RS 1 (in FIG. 5 , denoted by “ ”).
[0114] Preferably, the first data block intercepted from the eighth sub-frame comprises a reference symbol, so that the RS 1 can estimate the channel state from the MT 0 to the RS 1 after receiving the first data block. Certainly, if the first data block intercepted from the eighth sub-frame does not comprise a reference symbol, the sixth sending means 221 in the eNB 2 may firstly add the reference symbol into the first data block before sending the first data block, so that the RS 1 can estimate the channel state from the MT 0 to the RS 1 after receiving the first data block.
[0115] It is to be noted, the first data block intercepted from the eighth sub-frame should be sent within a specific time slot so that the RS 1 can just receive the first data block on a time frequency resource that becomes idle after the MT 0 finishes sending the uplink data ahead of time by GP/2.
[0116] Then, the third receiving means 123 in the interference eliminating device 12 in the RS 1 receives the first data block on a time frequency resource that becomes idle after the MT 0 finishes sending the uplink data ahead of time by GP/2, and receives a second data block in the frequency band from the eNB 2 to the RS 1 . After then, the two parts of data blocks are merged to get the eighth sub-frame from the eNB 2 .
[0117] Because the first data block in the eighth sub-frame is sent to the RS 1 using the frequency band from the MT 0 to the RS 1 , as shown in FIG. 5 , the RS 1 has already finished receiving the eighth sub-frame from the eNB 2 before starting to send the ninth sub-frame to the MT 0 so that the receiving of the eighth sub-frame and the sending of the ninth sub-frame of the RS 1 will not cause interference.
Embodiment 7
[0118] The embodiment is for the scenario that the eNB 2 and the RS 1 are under synchronization of GPS and the RS 1 sends the ninth sub-frame to the MT 0 after finishing receiving the eighth sub-frame from the eNB 2 . And, in the embodiment, the frequency band occupied by the data transmission between the eNB 2 and the RS 1 is the same as the frequency band occupied by the data transmission between the MT 0 and the RS 1 .
[0119] FIG. 13 shows a block diagram of system structure of eliminating interference by occupying the resource of the GP for data transmission when the eNB and RS are under synchronization of GPS, according to a seventh embodiment of the present invention. The interference eliminating device 13 in the RS 1 and the assisting interference eliminating device 23 in the eNB 2 are shown in FIG. 13 , wherein, the interference eliminating device 13 comprises the fourth receiving means 131 , the assisting interference eliminating device 23 comprises the seventh sending means 231 .
[0120] In the embodiment, the contents of FIG. 7 are taken as reference here together.
[0121] In FIG. 7 , the fifth sub-frame is a downlink sub-frame, the sixth sub-frame is a special sub-frame, the seventh sub-frame is an uplink sub-frame, the eighth sub-frame is an uplink sub-frame, and the ninth sub-frame is a downlink sub-frame. Wherein, Dw (DwPTS) in the sixth sub-frame is downlink synchronization time slot, G (GP) is guard period, and Up (UpPTS) is uplink synchronization time slot.
[0122] As shown in FIG. 7 , in the embodiment, assuming that the eighth sub-frame is “stolen UL”, which is taken as downlink sub-frame. That is, the eNB 2 sends the eighth sub-frame to the RS 1 , and the RS 1 sends the ninth sub-frame to the MT 0 after finishing receiving the eighth sub-frame from the eNB 2 .
[0123] Because there is transmission latency in the data transmission from the eNB 2 to the RS 1 , the RS 1 does not finish receiving the eighth sub-frame from the eNB 2 while preparing to send the ninth sub-frame to the MT 0 . Based on this, the eNB 2 sends part of data of the eighth sub-frame within the GP of specific sub-frame (the sixth sub-frame) in advance, and sends the remaining data of the eighth sub-frame by still using the original time frequency resources. In this way, the RS 1 just starts to send the ninth sub-frame to the MT 0 after finishing receiving, the eighth sub-frame from the eNB 2 .
[0124] To be specific, the seventh sending means 231 in the assisting interference eliminating device 23 in the eNB 2 sends to the RS 1 a first data block corresponding to GP/2 time length in the eighth sub-frame via the frequency band from the eNB 2 to the RS 1 within the GP of specific sub-frame.
[0125] Accordingly, considering the transmission latency from the eNB 2 to the RS 1 , the fourth receiving means 131 in the interference eliminating device 13 in the RS 1 receives the first data block from the eNB 2 within the specific time slot of GP.
[0126] Preferably, as shown in FIG. 7 , the fourth receiving means 131 in the RS 1 starts to receive the first data block from the eNB 2 at the GP/4 after the starting moment of GP, and finishes receiving the first data block from the eNB 2 at the GP/4 before the end moment of GP.
[0127] Based on this, considering the transmission latency of GP/2 from the eNB 2 to the RS 1 , in order to enable the fourth receiving means 131 in the RS 1 to receive the first data block from the eNB 2 within the specific time slot of GP, the seventh sending means 231 in the eNB 2 should start to send the first data block to the RS 1 at the last GP/4 of DwPTS time slot.
[0128] It is to be noted, usually, the downlink synchronous signal sent within DwPTS time slot only occupy the very narrow frequency band, which is different from the frequency band occupied by the downlink data transmission from the eNB 2 to the RS 1 , therefore, even if the eNB 2 starts to send the first data block to the RS 1 from the last GP/4 of the DwPTS time slot, it will not cause interference with that the eNB 2 sends the downlink synchronous signal within DwPTS time slot.
[0129] Certainly, the RS 1 may also start to receive the first data block from the eNB 2 at the starting time of GP, and accordingly, the eNB 2 needs to start to send the first data block to the RS 1 at the GP/2 before the starting time of GP.
Embodiment 8
[0130] The embodiment is for the scenario that the eNB 2 and the RS 1 are under synchronization of AI and the RS 1 sends the third sub-frame to the eNB 2 after finishing receiving the second sub-frame from the MT 0 . And, in the embodiment, the frequency band occupied by the data transmission between the eNB 2 and the RS 1 is different from the frequency band occupied by the data transmission between the MT 0 and the RS 1 .
[0131] FIG. 14 shows a block diagram of system structure of eliminating interference by reducing the length of the GP when the eNB and RS are under synchronization of AI, according to a eighth embodiment of the present invention. The MT 0 an interference eliminating device 14 in the RS 1 and an assisting interference eliminating device 24 in eNB 2 are shown in FIG. 14 , wherein the interference eliminating device 14 comprises a fourth sending means 141 , a fifth receiving means 142 and a fifth sending means 143 , and the assisting interference eliminating device 24 comprises a sixth receiving means 241 .
[0132] In the embodiment, the contents of FIG. 9 are taken as reference here together.
[0133] For the purpose of simplicity, the frequency band used for the data transmission between the eNB 2 and the RS 1 is called as the frequency band from the eNB 2 to the RS 1 ; the frequency band used for the data transmission between the MT 0 and the RS 1 is called as the frequency band from the MT 0 to the RS 1 .
[0134] Because the eNB 2 and the RS 1 are under synchronization of AI, therefore, referring to FIG. 2 , there is no interference between the eighth sub-frame and the ninth sub-frame, but the interference between the third sub-frame and the fourth sub-frame is more serious.
[0135] Similar to the embodiment 5, the MT 0 firstly sends the uplink synchronization code to the RS 1 at UpPTS time slot when the MT 0 performs random access. After the RS 1 receives the uplink synchronization code from the MT 0 , the fourth sending means 141 in the interference eliminating device 14 in the RS 1 sends the uplink timing advancing signaling to the MT 0 . Wherein, the uplink timing advancing signaling comprises information of timing advancing, and in the present invention, the information of timing advancing equals to the original timing advancing plus GP/2 timing advancing. Then, the MT 0 receives uplink timing advancing signaling from RS 1 , and the MT 0 may know when it should send uplink sub-frames to reach uplink synchronization with the RS 1 according to information of timing advancing comprised in the uplink timing advancing signaling.
[0136] Because the RS 1 adds GP/2 timing advancing to the original timing advancing, the MT 0 sends the second sub-frame (that is, the uplink sub-frame from the MT 0 to the RS 1 ) to the RS 1 ahead of the original sending moment by GP/2.
[0137] The fifth receiving means 142 in interference eliminating device 14 in the RS 1 starts to receive the second sub-frame from the MT 0 ahead of the original time by GP/2. Because the MT 0 starts to send the second sub-frame to the RS 1 ahead of receiving moment by GP/2, the fifth receiving means 142 in the RS 1 finishes receiving the second sub-frame from the MT 0 ahead of time by GP/2. Because The fifth receiving means 142 in the RS 1 finishes receiving the second sub-frame ahead of time by GP/2, accordingly, the fifth sending means 143 in interference eliminating device 14 in the RS 1 starts to send the third sub-frame (that is, the uplink sub-frame from the RS 1 to the eNB 2 ) to the eNB 2 ahead of time by GP/2.
[0138] Because the MT 0 finishes sending uplink data to the RS 1 ahead of time by GP/2, part of time-frequency resources of the MT 0 for sending uplink data become idle.
[0139] Based on this, the fifth sending means 143 in the interference eliminating device 14 in the RS 1 sends to the eNB 2 a first data block corresponding to GP/2 time length in the third sub-frame on the time frequency resource that becomes idle after the MT 0 finishes sending the uplink data ahead of time by GP/2, and at the same time sends to the eNB 2 the remaining second data block in the third sub-frame ahead of time by GP/2 in the frequency band from the RS 1 to the eNB 2 .
[0140] The sixth receiving means 241 in the assisting interference eliminating device 24 in the eNB 2 receives the first data block from the RS 1 in the frequency hand from the MT 0 to the RS 1 , and receives the second data block from the RS 1 in the frequency band from the RS 1 to the eNB 2 .
[0141] After the eNB 2 receives the first data block and the second data block on the different frequency bands, the two parts of data blocks are merged to get the third sub-frame from the RS 1 .
[0142] In a variation, if the frequency band occupied by the data transmission between the eNB 2 and the RS 1 is the same as the frequency band occupied by the data transmission between the MT 0 and the RS 1 , the RS 1 may send the first data block by only using the time frequency resource that becomes idle after the MT 0 finishes sending the uplink data ahead of time by GP/2. Based on this, the data block of (2P-GP/2) time length in the third sub-frame which is sent to the eNB 2 by the RS 1 is discarded, wherein P is the latency time of transmission from the RS 1 to the eNB 2 . If the latency time of transmission from the RS 1 to the eNB 2 is GP/2, a data block of GP/2 time length in the third sub-frame which is sent to the eNB 2 by the RS 1 is discarded.
[0143] The detailed embodiments of the present invention are described hereinbefore, it needs to be understood that the present invention is not limited to the aforesaid specific embodiments, those skilled in the art may make all kinds of variation or modification within the scope of the appended claims. | The present invention provides a method and a device for eliminating interference in a wireless relay TDD system. Data is sent between a relay station and a base station by occupying time slots of guard period, thereby the interference caused by non-synchronization between the base station and the relay station is eliminated. | 52,204 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2015-212125, filed on Oct. 28, 2015, the entire contents of which are incorporated herein by reference.
FIELD
[0002] The embodiments discussed herein are related to augmented reality.
BACKGROUND
[0003] In recent years, there has been performed display of contents, which is called augmented reality (hereinafter, called AR) and in which, by using a smartphone or the like incorporating a camera, markers installed in articles are image-captured, thereby displaying the contents on a captured image screen. In addition, in authoring in which an AR content is associated with an AR marker serving as a marker installed in an article, inputting of the AR content is performed in a state in which the AR marker is image-captured.
[0004] Related technologies are disclosed in, for example, Japanese Laid-open Patent Publication No. 2015-001875, Japanese Laid-open Patent Publication No. 2013-004001, and International Publication Pamphlet No. WO 2012/105175.
SUMMARY
[0005] According to an aspect of the invention, an information processing system includes circuitry configured to acquire a first image captured by an imaging device, extract, from the first image, a plurality of candidate areas each including an object having a shape corresponding to a shape of a marker to be used for augmented reality, control a display to display a first composite image that applies a predetermined graphical effect on the candidate areas in the first image, receive selection of a first area of the candidate areas from among the candidate areas, acquire identification information corresponding to a first marker included in the first area from a source other than the first image, receive an input corresponding to a first position on the first image as an arrangement position of content to be virtually arranged with reference to the first marker, convert the first position into positional information in a coordinate system corresponding to the first area, and store, in a memory, the positional information, the identification information, and the content in association with one another.
[0006] The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.
[0007] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF DRAWINGS
[0008] FIG. 1 is a block diagram illustrating an example of a configuration of an information processing device of a first embodiment;
[0009] FIG. 2 is a diagram illustrating an example of a content storage unit;
[0010] FIG. 3 is a diagram illustrating an example of a positional relationship;
[0011] FIG. 4 is a diagram illustrating another example of the positional relationship;
[0012] FIG. 5 is a diagram illustrating an example of extraction of AR marker candidates;
[0013] FIG. 6 is a diagram illustrating an example of a captured image screen at a time of editing;
[0014] FIG. 7 is a diagram illustrating another example of a captured image screen at a time of editing;
[0015] FIG. 8 is a diagram illustrating an example of a captured image screen at a time of display;
[0016] FIG. 9 is a diagram illustrating another example of a captured image screen at a time of display;
[0017] FIG. 10 is a flowchart illustrating an example of display control processing of the first embodiment;
[0018] FIG. 11 is a flowchart illustrating an example of content display processing;
[0019] FIG. 12 is a block diagram illustrating an example of a configuration of an information processing device of a second embodiment;
[0020] FIG. 13 is a flowchart illustrating an example of display control processing of the second embodiment;
[0021] FIG. 14 is a block diagram illustrating an example of a configuration of an information processing device of a third embodiment;
[0022] FIG. 15 is a flowchart illustrating an example of display control processing of the third embodiment; and
[0023] FIG. 16 is a diagram illustrating an example of a computer to execute a display control program.
DESCRIPTION OF EMBODIMENTS
[0024] Since an angle of view of a camera is narrow in a case where authoring is performed by using a terminal such as a smartphone, a range of AR contents able to be edited at one time becomes narrow. On the other hand, in a state in which all AR contents come within the angle of view, it becomes difficult to recognize an AR marker. Therefore, in a case where AR contents are arranged for the same AR marker over a wide range, it is difficult to simultaneously arrange or operate all the AR contents.
[0025] In one aspect, an object of the technology disclosed in embodiments is to set AR contents even at a distance at which it is difficult to recognize an AR marker.
[0026] Hereinafter, examples of a display control method, a display control program, and an information processing device, disclosed by the present application, will be described in detail, based on drawing. Note that the present embodiments do not limit the disclosed technology. In addition, the following embodiments may be arbitrarily combined to the extent that these do not contradict.
First Embodiment
[0027] FIG. 1 is a block diagram illustrating an example of a configuration of an information processing device of a first embodiment. An information processing device 100 illustrated in FIG. 1 extracts a predetermined shape from an acquired captured image and receives inputting of identification information and specification of a position on a captured image screen. The information processing device 100 causes the storage unit 120 to store therein a positional relationship between an extraction position of the predetermined shape and the specified position while associating the positional relationship with the input identification information. Upon extracting, based on an AR marker having a predetermined shape, identification information, the information processing device 100 displays an AR content corresponding to the identification information, in accordance with a positional relationship stored in the storage unit 120 . From this, the information processing device 100 is able to set the AR content even at a distance at which it is difficult to recognize the AR marker.
[0028] As illustrated in FIG. 1 , the information processing device 100 includes a camera 110 , a display operation unit 111 , a storage unit 120 , and a control unit 130 . Note that in addition to the functional units illustrated in FIG. 1 , the information processing device 100 may include various kinds of functional units included in a known computer, for example, functional units such as a communication unit, various kinds of input devices, and a sound-output device. As examples of the information processing device 100 , various kinds of terminals such as a tablet terminal, a smartphone, and a mobile phone may be adopted.
[0029] The camera 110 image-captures an object assigned with an AR marker or an AR marker candidate. The camera 110 uses, as an imaging element, for example, a complementary metal oxide semiconductor (CMOS) image sensor, a charge coupled device (CCD) image sensor, or the like, thereby image-capturing an image. The camera 110 subjects light received by the imaging element to photoelectric conversion and performs analog-digital (A-D) conversion, thereby generating a captured image. The camera 110 outputs the generated captured image to the control unit 130 . In addition, if the control unit 130 inputs a stop signal, the camera 110 stops outputting of a captured image, and if a start signal is input, the camera 110 starts outputting of a captured image. In other words, if, for example, the start signal is input, the camera 110 outputs a captured image as a moving image, and if the stop signal is input, the camera 110 stops outputting of the moving image.
[0030] Note that as an AR marker to be image-captured, a marker, which stores information by dividing, into areas, an area within, for example, a black border of a white square shape having the black border and paining the individual areas in white and black, may be used. In addition, regarding the AR marker, while not being able to be recognized as an AR marker on a captured image, a quadrangle area seems to be an AR marker in some cases. In this case, the relevant area is defined as an AR marker candidate. Furthermore, AR marker candidates include an area that is close to a square shape and that seems to be an AR marker while not being an AR marker.
[0031] The display operation unit 111 corresponds to a display device for displaying various kinds of information and an input device to receive various kinds of operations from a user. As the display device, the display operation unit 111 is realized by, for example, a liquid crystal display or the like. In addition, as the input device, the display operation unit 111 is realized by, for example, a touch panel or the like. In other words, in the display operation unit 111 , the display device and the input device are integrated. The display operation unit 111 outputs, as operation information to the control unit 130 , an operation input by the user.
[0032] The storage unit 120 is realized by, for example, a semiconductor memory element such as a random access memory (RAM) or a flash memory or a storage device such as a hard disk or an optical disk. The storage unit 120 includes a content storage unit 121 . In addition, the storage unit 120 stores therein information used for processing in the control unit 130 .
[0033] The content storage unit 121 stores therein AR contents while associating the AR contents with marker IDs (Identifiers) of respective AR markers. FIG. 2 is a diagram illustrating an example of a content storage unit. As illustrated in FIG. 2 , the content storage unit 121 includes items such as a “marker ID”, a “positional relationship”, and a “content”. The content storage unit 121 stores therein marker IDs while associating each one of the marker IDs with, for example, groups of positional relationships and contents.
[0034] The “marker ID” is an identifier to identify an AR marker. The “positional relationship” is information indicating a relative position between an AR content and an AR marker. The “positional relationship” is able to be expressed by coordinates with, for example, a side of an AR marker as a reference value. The “content” is an AR content to be displayed in accordance with an AR marker. As the “content”, for example, an arrow “←” indicating a check point, a character string “attention!” for calling attention, an image, a 3 D content, a moving image, and so forth may be used. In an example of the first row of FIG. 2 , a content “←” and so forth to be displayed at a position of coordinates (1,1) are associated with a marker ID “M001”. Note that the coordinates are expressed by, for example, 3 axes of x, y, and z and the z-axis may be omitted in a case where the z-axis is “0”.
[0035] Here, by using FIG. 3 and FIG. 4 , a positional relationship between an AR marker and an AR content will be described. FIG. 3 is a diagram illustrating an example of a positional relationship. In the example of FIG. 3 , a star serving as an AR content corresponds to a case of being located at “2” from the center of an AR marker in an x-axis direction and being located at “0” from the center of the AR marker in a y-axis direction, in other words, being located at coordinates (2,0) while a side of the AR marker is defined as “1”.
[0036] FIG. 4 is a diagram illustrating another example of the positional relationship. FIG. 4 is an example of display of an AR content in an image obtained by image-capturing an oblique lateral view of the AR marker. In the example of FIG. 4 , a value of the z-axis is calculated based on a ratio between a length of the x-axis of the AR marker and a length of the y-axis thereof, and the position of the star serving as the AR content is expressed based on the coordinates (x,y,z). In addition, in the example of FIG. 4 , the magnitude and direction of inclination, in other words, the positive or negative of the z-axis is calculated in accordance with ratios of facing sides of the AR marker.
[0037] Returning to the description of FIG. 1 , by using a RAM as a working area, a program stored in an internal storage device is executed by, for example, a central processing unit (CPU), a micro processing unit (MPU), or the like, thereby realizing the control unit 130 . In addition, the control unit 130 may be realized by, for example, an integrated circuit such as an application specific integrated circuit (ASIC) or a field programmable gate array (FPGA). The control unit 130 includes a reception unit 131 , a storage control unit 132 , and a display control unit 133 and realizes or performs functions and operations of information processing to be described later. Note that an inner structure of the control unit 130 is not limited to the configuration illustrated in FIG. 1 and may adopt another configuration if the other configuration performs the information processing to be described later. In addition, the control unit 130 causes the display operation unit 111 to display a captured image input by the camera 110 .
[0038] If the display operation unit 111 inputs operation information to the effect that authoring is to be initiated, the reception unit 131 acquires a captured image from the camera 110 and outputs the stop signal to the camera 110 . At this time, the reception unit 131 causes the display operation unit 111 to display the acquired captured image. The reception unit 131 scans the acquired captured image and determines whether or not one or more AR marker candidates exist. In a case where no AR marker candidate exists, the reception unit 131 outputs the start signal to the camera 110 .
[0039] In a case where one or more AR marker candidate exists, the reception unit 131 extracts shapes of the respective AR marker candidates from the captured image. In other words, the reception unit 131 extracts predetermined shapes from the acquired captured image. The reception unit 131 causes the AR marker candidates, from which shapes thereof on the captured image are extracted, to be highlighted. Here, each of the predetermined shapes only has to be a shape from which the size and inclination of the relevant shape are able to be measured or calculated.
[0040] On the captured image caused to be displayed by the display operation unit 111 , the reception unit 131 starts receiving selection for the AR marker candidates. The reception unit 131 determines whether or not selection is received. In a case where no selection is received, the reception unit 131 waits for reception of selection. In a case where selection is received, the reception unit 131 starts receiving a marker ID.
[0041] The reception unit 131 determines whether or not a marker ID is received. In a case where no marker ID is received, the reception unit 131 waits for reception of a marker ID. In a case where a marker ID is received, the reception unit 131 associates the received marker ID with the AR marker candidate for which the selection is received and implements authoring of a AR content corresponding to the relevant AR marker candidate.
[0042] The reception unit 131 receives the marker ID, based on, for example, inputting to the display operation unit 111 , performed by a user. In addition, the reception unit 131 may receive, for example, identification information, in other words, a marker ID, extracted by recognizing an AR marker immediately before this scanning of the captured image. Furthermore, the reception unit 131 may implement the authoring in a state in which the user comes close to AR marker candidates once and moves away therefrom after causing the AR marker to be recognized and a wide angle of view is secured.
[0043] Here, extraction of AR marker candidates will be described by using FIG. 5 . FIG. 5 is a diagram illustrating an example of extraction of AR marker candidates. As illustrated in FIG. 5 , in a captured image screen 10 , areas 11 to 13 are extracted as AR marker candidates. In the captured image screen 10 , the user performs selection on the AR marker candidates of the areas 11 to 13 . In the example of FIG. 5 , an AR marker candidate of the area 11 installed in an article 14 is selected. Note that while not being an AR marker, each of AR marker candidates of the areas 12 and 13 is an area that seems to be an AR marker.
[0044] As the authoring, first the reception unit 131 receives a position on the captured image, at which an AR content is to be arranged. Regarding, for example, specification of a position, the reception unit 131 receives specification of a position with a side of an AR marker as a reference value. The reception unit 131 outputs, to the storage control unit 132 , the received position on the captured image, at which the AR content is to be arranged, while associating, with the marker ID, the received position on the captured image, at which the AR content to be arranged. In other words, the reception unit 131 outputs, to the storage control unit 132 , the position on the captured image, at which the AR content is to be arranged, while associating, with the marker ID received for the corresponding AR marker candidate, the position on the captured image, at which the AR content to be arranged. In addition, in a case where AR contents are to be arranged, the reception unit 131 outputs, to the storage control unit 132 , positions of the AR contents and the marker ID while associating the positions of the respective AR contents with the marker ID. Furthermore, the reception unit 131 outputs, to the storage control unit 132 , the position of the AR marker candidate for which the selection is received and the input AR contents.
[0045] If the reception unit 131 inputs the position of the corresponding AR marker candidate, the marker ID, and the positions of the AR contents, the storage control unit 132 stores, in the content storage unit 121 , a positional relationship between the position of the corresponding AR marker candidate and the positions of the AR contents while associating the positional relationship with the marker ID. In addition, the storage control unit 132 stores, in the content storage unit 121 , the AR contents while associating the AR contents with the marker ID. In other words, the storage control unit 132 stores an authoring result in the content storage unit 121 . Here, the positional relationship may be expressed by relative coordinates in which the position of, for example, the corresponding AR marker candidate serve as a reference. If storing of the authoring result is completed, the storage control unit 132 outputs the start signal to the camera 110 .
[0046] Here, by using FIG. 6 and FIG. 7 , the authoring, in other words, editing of AR contents will be described. FIG. 6 is a diagram illustrating an example of a captured image screen at a time of editing. As illustrated in FIG. 6 , an AR marker candidate 21 is displayed in a captured image screen 20 at a time of editing. In the captured image screen 20 , first, a user selects an AR marker candidate 21 and inputs a marker ID. In the captured image screen 20 , next, the user inputs AR contents 22 to 26 . At this time, the captured image screen 20 corresponds to an image image-captured from a distance at which it is difficult to recognize the AR marker candidate 21 as an AR marker.
[0047] FIG. 7 is a diagram illustrating another example of a captured image screen at a time of editing. FIG. 7 is a captured image screen at a time of editing in a case where the AR marker candidate of the area 11 is selected in the example of FIG. 5 . As illustrated in FIG. 7 , in a captured image screen 30 , a user selects an AR marker candidate 31 installed in the article 14 and inputs a marker ID. In the captured image screen 30 , next, the user inputs AR contents 32 and 33 . In the same way as the captured image screen 20 in FIG. 6 , the captured image screen 30 at this time corresponds to an image image-captured from a distance at which it is difficult to recognize the AR marker candidate 31 as an AR marker.
[0048] Returning to the description of FIG. 1 , upon recognizing an AR marker within a captured image in a case where the display operation unit 111 displays the captured image input by the camera 110 , the display control unit 133 extracts identification information, in other words, a marker ID, based on the recognized AR marker. Upon extracting the marker ID, the display control unit 133 references the content storage unit 121 and causes an AR content corresponding to the marker ID to be displayed on the captured image screen, based on a positional relationship.
[0049] Here, by using FIG. 8 and FIG. 9 , a captured image screen at a time of display of an AR content will be described. FIG. 8 is a diagram illustrating an example of a captured image screen at a time of display. As illustrated in FIG. 8 , in a captured image screen 40 , if an AR marker 41 is recognized, the AR contents 22 to 24 associated with the marker ID of the AR marker 41 are displayed. Here, the marker ID of the AR marker 41 is the same as the marker ID of the AR marker candidate 21 in FIG. 6 . In the captured image screen 40 , the AR marker 41 is located on a right side on the captured image screen, and the AR contents 22 to 24 located on the left side and the upper side of the AR marker 41 are displayed. In other words, in the captured image screen 40 , since the user comes closer to the AR marker 41 than in the captured image screen 20 in FIG. 6 , it is possible to recognize the AR marker 41 . However, since the angle of view is narrow, a state in which it is difficult to display all the AR contents set in the captured image screen 20 in FIG. 6 is produced.
[0050] Next, it is assumed that the user moves the information processing device 100 so that the AR marker 41 moves from the right side on the captured image screen and is located on a left side thereon, compared with the state of FIG. 8 . A captured image screen in this case is illustrated in FIG. 9 . FIG. 9 is a diagram illustrating another example of a captured image screen at a time of display. In a captured image screen 42 in FIG. 9 , the AR marker 41 is located on a left side on the captured image screen, and the AR contents 24 to 26 located on the right side and the upper side of the AR marker 41 are displayed.
[0051] Next, an operation of the information processing device 100 of the first embodiment will be described. FIG. 10 is a flowchart illustrating an example of display control processing of the first embodiment.
[0052] The control unit 130 outputs the start signal to the camera 110 . The control unit 130 causes the display operation unit 111 to display a captured image input by the camera 110 . If the display operation unit 111 inputs operation information to the effect that authoring is to be initiated, the reception unit 131 acquires a captured image from the camera 110 and outputs the stop signal to the camera 110 . If the stop signal is input by the control unit 130 , the camera 110 stops outputting of a captured image (step S 1 ).
[0053] The reception unit 131 scans the acquired captured image (step S 2 ) and determines whether or not one or more AR marker candidates exist (step S 3 ). In a case where no AR marker candidate exists (step S 3 : negative), the reception unit 131 outputs the start signal to the camera 110 and returns to step S 1 .
[0054] In a case where one or more AR marker candidates exist (step S 3 : affirmative), the reception unit 131 extracts shapes of the respective AR marker candidates from the captured image. The reception unit 131 causes the AR marker candidates, from which shapes thereof on the captured image are extracted, to be highlighted (step S 4 ). On the captured image caused to be displayed by the display operation unit 111 , the reception unit 131 starts receiving selection for the AR marker candidates (step S 5 ). The reception unit 131 determines whether or not selection is received (step S 6 ). In a case where no selection is received (step S 6 : negative), the reception unit 131 repeats the determination in step S 6 .
[0055] In a case where selection is received (step S 6 : affirmative), the reception unit 131 starts receiving a marker ID (step S 7 ). The reception unit 131 determines whether or not a marker ID is received (step S 8 ). In a case where no marker ID is received (step S 8 : negative), the reception unit 131 repeats the determination in step S 8 .
[0056] In a case where a marker ID is received (step S 8 : affirmative), the reception unit 131 associates the received marker ID with the AR marker candidate for which the selection is received and implements authoring of a AR content corresponding to the relevant AR marker candidate (step S 9 ). As the authoring, first the reception unit 131 receives a position on the captured image, at which the AR content is to be arranged. The reception unit 131 outputs, to the storage control unit 132 , the position on the captured image, at which the AR content is to be arranged, while associating, with a marker ID received for the AR marker candidate, the position on the captured image, at which the AR content to be arranged. In addition, the reception unit 131 outputs, to the storage control unit 132 , the position of the AR marker candidate for which the selection is received and the input AR content.
[0057] If the reception unit 131 inputs the position of the corresponding AR marker candidate, the marker ID, and the position of the AR content, the storage control unit 132 stores, in the content storage unit 121 , a positional relationship between the position of the AR marker candidate and the position of the AR content while associating the positional relationship with the marker ID. In addition, the storage control unit 132 stores, in the content storage unit 121 , the AR content while associating the AR content with the marker ID. In other words, the storage control unit 132 stores an authoring result in the content storage unit 121 (step S 10 ). If storing of the authoring result is completed, the storage control unit 132 outputs the start signal to the camera 110 . If the start signal is input, the camera 110 starts outputting of a captured image (step S 11 ).
[0058] Upon recognizing an AR marker within the captured image in a case where the display operation unit 111 displays the captured image input by the camera 110 , the display control unit 133 performs content display processing (step S 12 ). Here, the content display processing will be described by using FIG. 11 . FIG. 11 is a flowchart illustrating an example of the content display processing.
[0059] The display control unit 133 recognizes an AR marker on a captured image (step S 121 ) and extracts identification information, based on the recognized AR marker (step S 122 ). Upon extracting identification information, in other words, a marker ID, the display control unit 133 references the content storage unit 121 and causes an AR content corresponding to the marker ID to be displayed on a captured image screen (step S 123 ) and returns to former processing. From this, the display control unit 133 is able to display the AR content corresponding to the AR marker.
[0060] Returning to the description of the display control processing in FIG. 10 , if the content display processing finishes, the display control unit 133 terminates the display control processing. From this, the information processing device 100 is able to set the AR content even at a distance at which it is difficult to recognize the AR marker. In other words, it becomes possible for the information processing device 100 to perform the authoring having a range broader than in the related art. In addition, the information processing device 100 is able to display the set AR content.
[0061] In this way, the information processing device 100 extracts a predetermined shape from the acquired captured image and receives inputting of the identification information and specification of a position on the captured image screen. In addition, the information processing device 100 causes the storage unit 120 to store therein a positional relationship between an extraction position of the predetermined shape and the specified position while associating the positional relationship with the input identification information. In addition, upon extracting, based on the AR marker having a predetermined shape, identification information, the information processing device 100 displays an AR content corresponding to the identification information, in accordance with the positional relationship stored in the storage unit 120 . As a result, it is possible to set the AR content even at a distance at which it is difficult to recognize the AR marker.
[0062] Regarding specification of a position, the information processing device 100 receives specification of a position with a side of an AR marker as a reference value. As a result, it is possible to easily arrange an AR content at a relative position based on the corresponding AR marker.
[0063] In addition, the information processing device 100 receives, as inputting of identification information, the identification information most recently extracted based on an AR marker. As a result, it is possible to easily receive the inputting of the identification information.
[0064] In addition, in the information processing device 100 , a predetermined shape is a shape from which the size and inclination of the shape are able to be measured or calculated. As a result, it is possible to display an AR content corresponding to the image-capturing direction of an AR marker.
[0065] In addition, the information processing device 100 extracts a predetermined shape from an acquired captured image and receives inputting of identification information. In addition, upon receiving specification of a position at which an AR content is to be arranged on a captured image screen, the information processing device 100 causes the storage unit 120 to store therein a positional relationship between an extraction position of the predetermined shape and the specified position while associating the positional relationship with the input identification information. In addition, upon extracting, based on an AR marker having a predetermined shape, identification information, the information processing device 100 displays an AR content corresponding to the identification information, in accordance with the positional relationship stored in the storage unit 120 . As a result, it is possible to set the AR content even at a distance at which it is difficult to recognize the AR marker.
Second Embodiment
[0066] While, in the above-mentioned first embodiment, the authoring is implemented after a marker ID serving as the identification information is received, a marker ID may be received after the authoring is implemented, and an embodiment in this case will be described as a second embodiment. FIG. 12 is a block diagram illustrating an example of a configuration of an information processing device of the second embodiment. Note that the same symbol is assigned to the same configuration as that of the information processing device 100 of the first embodiment, thereby omitting the redundant descriptions of a configuration and an operation thereof.
[0067] An information processing device 200 of the second embodiment includes a reception unit 231 in place of the reception unit 131 in the information processing device 100 of the first embodiment.
[0068] If the display operation unit 111 inputs operation information to the effect that authoring is to be initiated, the reception unit 231 acquires a captured image from the camera 110 and outputs the stop signal to the camera 110 . At this time, the reception unit 231 causes the display operation unit 111 to display the acquired captured image. The reception unit 231 scans the acquired captured image and determines whether or not one or more AR marker candidates exist. In a case where no AR marker candidate exists, the reception unit 231 outputs the start signal to the camera 110 .
[0069] In a case where one or more AR marker candidates exist, the reception unit 231 extracts shapes of the respective AR marker candidates from the captured image. In other words, the reception unit 231 extracts predetermined shapes from the acquired captured image. The reception unit 231 causes the AR marker candidates, from which shapes thereof on the captured image are extracted, to be highlighted.
[0070] On the captured image caused to be displayed by the display operation unit 111 , the reception unit 231 starts receiving selection for the AR marker candidates. The reception unit 231 determines whether or not selection is received. In a case where no selection is received, the reception unit 231 waits for reception of selection. In a case where the selection is received, the reception unit 231 implements authoring of a AR content corresponding to the AR marker candidate for which the selection is received.
[0071] As the authoring, first the reception unit 231 receives a position on the captured image, at which the corresponding AR content is to be arranged. The reception unit 231 receives specification of a position of the corresponding AR content with a position of, for example, the corresponding AR marker candidate as a reference. If inputting of the corresponding AR content is completed and the authoring is completed, the reception unit 231 starts receiving a marker ID. Note that a user may come close to the corresponding AR marker candidate, thereby causing the reception unit 231 to recognize an AR marker and to receive the corresponding marker ID.
[0072] The reception unit 231 determines whether or not a marker ID is received. In a case where no marker ID is received, the reception unit 231 waits for reception of a marker ID. In a case where a marker ID is received, the reception unit 231 outputs, to the storage control unit 132 , the received marker ID while associating the received marker ID with the AR content for which the authoring is completed and the position of the AR content. In addition, the reception unit 231 outputs, to the storage control unit 132 , the position of the AR marker candidate for which the selection is received.
[0073] Next, an operation of the information processing device 200 of the second embodiment will be described. Since, in the second embodiment, compared with the display control processing of the first embodiment, processing operations in steps S 1 to S 6 and S 10 to S 12 are the same as those of the first embodiment, the descriptions thereof will be omitted. Since in the second embodiment, processing operations in steps S 21 to S 23 are performed in place of those in steps S 7 to S 9 in the first embodiment, steps S 21 to S 23 will be described. FIG. 13 is a flowchart illustrating an example of display control processing of the second embodiment.
[0074] In a case where selection is received (step S 6 : affirmative), the reception unit 231 implements authoring of an AR content corresponding to the AR marker candidate for which the selection is received (step S 21 ). As the authoring, first the reception unit 231 receives a position on the captured image, at which the corresponding AR content is to be arranged. The reception unit 231 receives specification of a position of the corresponding AR content with a position of, for example, the corresponding AR marker candidate as a reference. If inputting of the corresponding AR content is completed and the authoring is completed, the reception unit 231 starts receiving a marker ID (step S 22 ).
[0075] The reception unit 231 determines whether or not a marker ID is received (step S 23 ). In a case where no marker ID is received (step S 23 : negative), the reception unit 231 repeats the determination in step S 23 . In a case where a marker ID is received (step S 23 : affirmative), the reception unit 131 outputs, to the storage control unit 132 , the received marker ID while associating the received marker ID with the AR content for which the authoring is completed and the position of the AR content. In addition, the reception unit 231 outputs, to the storage control unit 132 , the position of the AR marker candidate for which the selection is received. From this, the information processing device 200 is able to set the AR content even at a distance at which it is difficult to recognize an AR marker. In other words, it becomes possible for the information processing device 200 to perform the authoring having a range broader than in the related art. In addition, the information processing device 200 is able to display the set AR content.
Third Embodiment
[0076] In each of the above-mentioned embodiments, a case where no AR content is associated with the marker ID of an AR marker before authoring is described as an example. In contrast, authoring may be performed on an AR marker whose marker ID is associated with an AR content, and an embodiment in this case will be described as a third embodiment. FIG. 14 is a block diagram illustrating an example of a configuration of an information processing device of the third embodiment. Note that the same symbol is assigned to the same configuration as that of the information processing device 100 of the first embodiment, thereby omitting the redundant descriptions of a configuration and an operation thereof.
[0077] An information processing device 300 of the third embodiment includes a reception unit 331 and a storage control unit 332 in place of the reception unit 131 and the storage control unit 132 , respectively, in the information processing device 100 of the first embodiment.
[0078] If the display operation unit 111 inputs operation information to the effect that authoring is to be initiated, the reception unit 331 acquires a captured image from the camera 110 and outputs the stop signal to the camera 110 . At this time, the reception unit 331 causes the display operation unit 111 to display the acquired captured image. The reception unit 331 scans the acquired captured image and determines whether or not one or more AR marker candidates exist. In a case where no AR marker candidate exists, the reception unit 331 outputs the start signal to the camera 110 .
[0079] In a case where one or more AR marker candidates exist, the reception unit 331 extracts shapes of the respective AR marker candidates from the captured image. In other words, the reception unit 331 extracts predetermined shapes from the acquired captured image. The reception unit 331 causes the AR marker candidates, from which shapes thereof on the captured image are extracted, to be highlighted.
[0080] On the captured image caused to be displayed by the display operation unit 111 , in other words, a captured image screen, the reception unit 331 starts receiving selection for the AR marker candidates. The reception unit 331 determines whether or not selection is received. In a case where no selection is received, the reception unit 331 waits for reception of selection. In a case where the selection is received, the reception unit 231 starts receiving a marker ID.
[0081] The reception unit 331 determines whether or not a marker ID is received. In a case where no marker ID is received, the reception unit 331 waits for reception of a marker ID. In a case where a marker ID is received, the reception unit 331 references the content storage unit 121 and causes an AR content corresponding to the marker ID to be displayed on the captured image screen, based on a positional relationship. Note that regarding an AR content, no information of a positional relationship may exist and in that case, the AR content is displayed at a preliminarily defined position on the captured image screen, such as the upper right of the screen.
[0082] The reception unit 331 implements authoring of an AR content corresponding to an AR marker candidate. The reception unit 331 receives a position on the captured image, in other words, the captured image screen, at which the corresponding AR content is to be arranged. In addition, for an already arranged AR content, the reception unit 331 receives specification of a specific arrangement position on the captured image screen. At this time, in a case where the already arranged AR content has information of a positional relationship, the information of a positional relationship is updated, and in a case where the relevant AR content has no information of a positional relationship, information of a positional relationship with the position of the corresponding AR marker candidate is generated. The reception unit 331 outputs, to the storage control unit 332 , the position on the captured image, at which the corresponding AR content is to be arranged, while associating the position on the captured image with the corresponding marker ID received for the corresponding AR marker candidate. In addition, the reception unit 331 outputs, to the storage control unit 332 , the position of the AR marker candidate for which the selection is received and the input AR content.
[0083] In this way, the reception unit 331 extracts a predetermined shape from the acquired captured image and receives inputting of identification information. In addition, the reception unit 331 references the content storage unit 121 and causes an AR content to be displayed on the captured image screen, the AR content being associated with the input identification information and being stored. In other words, the reception unit 331 has functions of both a reception unit and a first display control unit. In addition, at this time, the display control unit 133 has a function of a second display control unit.
[0084] If the reception unit 331 inputs the position of the corresponding AR marker candidate, the marker ID, and the position of the corresponding AR content, the storage control unit 332 stores, in the content storage unit 121 , a positional relationship between the position of the AR marker candidate and the position of the AR content while associating the positional relationship with the marker ID. In addition, the storage control unit 132 stores, in the content storage unit 121 , a newly input AR content while associating the newly input AR content with the corresponding marker ID. At this time, regarding an AR content already stored in the content storage unit 121 , the storage control unit 332 updates, with a new positional relationship, the positional relationship of the relevant AR content. In addition, in a case where the relevant AR content has no information of a positional relationship, a new positional relationship is stored while being associated with the relevant AR content. In other words, the storage control unit 332 stores an authoring result in the content storage unit 121 . If storing of the authoring result is completed, the storage control unit 332 outputs the start signal to the camera 110 .
[0085] Next, an operation of the information processing device 300 of the third embodiment will be described. Since, in the third embodiment, compared with the display control processing of the first embodiment, processing operations in steps S 1 to S 8 , S 11 , and S 12 are the same as those of the first embodiment, the descriptions thereof will be omitted. Since in the third embodiment, processing operations in steps S 31 to S 33 are performed in place of those in steps S 9 and S 10 in the first embodiment, steps S 31 to S 33 will be described. FIG. 15 is a flowchart illustrating an example of display control processing of the third embodiment.
[0086] In a case where a marker ID is received (step S 8 : affirmative), the reception unit 331 references the content storage unit 121 and causes an AR content corresponding to the marker ID to be displayed on a captured image screen, based on a positional relationship.
[0087] The reception unit 331 implements authoring of an AR content corresponding to an AR marker candidate (step S 32 ). The reception unit 331 receives a position on a captured image, at which the corresponding AR content is to be arranged. In addition, for an already arranged AR content, the reception unit 331 receives specification of a specific arrangement position on the captured image screen. The reception unit 331 outputs, to the storage control unit 332 , a position on the captured image, at which the corresponding AR content is to be arranged, while associating the position on the captured image with the corresponding marker ID received for the corresponding AR marker candidate. In addition, the reception unit 331 outputs, to the storage control unit 332 , the position of the AR marker candidate for which the selection is received and the input AR content.
[0088] If the reception unit 331 inputs the position of the corresponding AR marker candidate, the marker ID, and the position of the corresponding AR content, the storage control unit 332 stores, in the content storage unit 121 , a positional relationship between the position of the AR marker candidate and the position of the AR content while associating the positional relationship with the marker ID. In addition, the storage control unit 132 stores, in the content storage unit 121 , a newly input AR content while associating the newly input AR content with the corresponding marker ID. In other words, the storage control unit 332 stores an authoring result in the content storage unit 121 (step S 33 ). From this, the information processing device 300 is able to update and set the AR content even at a distance at which it is difficult to recognize an AR marker. In other words, it becomes possible for the information processing device 300 to perform the authoring having a range broader than in the related art. In addition, the information processing device 300 is able to display the set AR content.
[0089] In this way, the information processing device 300 extracts a predetermined shape from the acquired captured image and receives inputting of identification information. In addition, the information processing device 300 references a storage content of the storage unit 121 storing therein AR contents while associating the AR contents with identification information and causes an AR content to be displayed on the captured image screen, the AR content being associated with the input identification information and being stored. In addition, upon receiving, for the displayed AR content, specification of a specific arrangement position on the captured image screen, the information processing device 300 causes the storage unit 120 to store therein a positional relationship between the extraction position of the predetermined shape and the specified specific arrangement position while associating the positional relationship with the input identification information. In addition, upon extracting, based on an AR marker having the predetermined shape, identification information, the information processing device 300 displays an AR content corresponding to the identification information, in accordance with the corresponding positional relationship stored in the storage unit 120 . As a result, it is possible to set the AR content even at a distance at which it is difficult to recognize the AR marker.
[0090] Note that while, in each of the above-mentioned embodiments, an AR marker is used as a marker for associating an AR content, there is no limitation thereto. For example, a bar code, a QR code (registered trademark), feature extraction based on image recognition, and so forth, which are each able to recognize a target object, are available as the marker.
[0091] In addition, while, in each of the above-mentioned embodiments, an image captured by the camera 110 is defined as a target of processing, there is no limitation thereto. For example, a captured image, which is preliminarily image-captured by another camera and which includes AR marker candidates stored in a storage medium, may be defined as a target of processing.
[0092] In addition, individual illustrated configuration elements of individual units do not have to be physically configured as illustrated in drawings. In other words, a specific embodiment of the distribution or integration of the individual units is not limited to one of embodiments illustrated in drawings, and all or some of the individual units may be configured by being functionally or physically integrated or distributed in arbitrary units in accordance with various loads, various statuses of use, and so forth. For example, the reception unit 131 and the storage control unit 132 may be integrated. In addition, the individual processing operations illustrated in drawings are not limited to the above-mentioned orders, may be simultaneously implemented insofar as contents of processing operations do not contradict one another, and may be implemented by changing the orders thereof.
[0093] Furthermore, all or arbitrary part of various kinds of processing functions performed in each of devices may be performed on a CPU (or a microcomputer such as an MPU or a micro controller unit (MCU)). It goes without saying that all or arbitrary part of various kinds of processing functions may be performed on a program analyzed and performed in the CPU (or the microcomputer such as the MPU or the MCU) or may be performed on hardware based on hard-wired logic.
[0094] By the way, various kinds of processing described in each of the above-mentioned embodiments may be realized by causing a computer to execute a preliminarily prepared program. Therefore, in what follows, an example of a computer to execute a program having the same functions as those of each of the above-mentioned embodiments will be described. FIG. 16 is a diagram illustrating an example of a computer to execute a display control program.
[0095] As illustrated in FIG. 16 , a computer 400 includes a CPU 401 to perform various kinds of arithmetic processing operations, an input device 402 to receive data inputs, and a monitor 403 . In addition, the computer 400 includes a medium reading device 404 to read programs and so forth from a storage medium, an interface device 405 for being coupled to various kinds of devices, and a communication device 406 for being coupled to another information processing device or the like by using a wired line or wireless. In addition, the computer 400 includes a RAM 407 to temporarily store therein various kinds of information, and a hard disk device 408 . In addition, the individual devices 401 to 408 are coupled to a bus 409 .
[0096] In the hard disk device 408 , a display control program having the same functions as those of the individual processing units of the reception unit 131 , 231 , or 331 , the storage control unit 132 or 332 , and the display control unit 133 , illustrated in FIG. 1 , FIG. 12 , or FIG. 14 . In addition, in the hard disk device 408 , various kinds of data for realizing the content storage unit 121 and the display control program are stored.
[0097] The input device 402 receives, from a user of the computer 400 , inputting of various kinds of information such as, for example, operation information. The monitor 403 displays, for the user of the computer 400 , various kinds of screens such as, for example, captured image screens. The camera 110 is coupled to the interface device 405 , for example. The communication device 406 is coupled to, for example, a network, not illustrated, and exchanges various kinds of information with another information processing device.
[0098] The CPU 401 reads individual programs stored in the hard disk device 408 and deploys and executes the individual programs in the RAM 407 , thereby performing various kinds of processing. In addition, these programs are able to cause the computer 400 to function as the reception unit 131 , 231 , or 331 , the storage control unit 132 or 332 , and the display control unit 133 illustrated in FIG. 1 , FIG. 12 , or FIG. 14 .
[0099] Note that the above-mentioned display control program does not have to be stored in the hard disk device 408 . The computer 400 may read and execute, for example, a program stored in a storage medium readable by the computer 400 . The storage medium readable by the computer 400 corresponds to, for example, a portable recording medium such as a CD-ROM, a DVD disk, or a universal serial bus (USB) memory, a semiconductor memory such as a flash memory, a hard disk drive, or the like. In addition, the display control program may be stored in advance in a device coupled to a public line, the Internet, a LAN, and so forth, and the computer 400 may read, from these, and execute the display control program.
[0100] All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention. | A system includes circuitry configured to acquire a first image, extract a plurality of candidate areas each including an object having a shape corresponding to a shape of a marker to be used for augmented reality, control a display to display a first composite image that applies a predetermined graphical effect on the candidate areas in the first image, receive selection of a first area from among the candidate areas, acquire identification information corresponding to a first marker included in the first area from a source other than the first image, receive an input corresponding to a first position on the first image as an arrangement position of content to be virtually arranged with reference to the first marker, convert the first position into positional information in a coordinate system corresponding to the first area, and store the positional information, the identification information, and the content. | 56,145 |
FIELD OF THE INVENTION
[0001] The present invention relates to a transducer for measurement signals measured by a sensor and, more particularly, relates to a USB transducer which transmits measurement signals to a USB terminal of a computer through a USB cable.
BACKGROUND OF THE INVENTION
[0002] In the field of equipment for environmental analysis, process analysis, laboratory analysis, and industrial analysis, measuring instruments and measuring systems that display measurement signals measured by various kinds of sensors or that convert the signals into an analog output for transmission are generically called transducers. Generally, such transducers are provided with switches or like operating parts for making settings for the transducer itself or for controlling the sensor.
[0003] FIG. 7 shows a prior art transducer. In the figure, the transducer 10 is connected to a sensor 11 and external power supply 12 , and the output of the transducer 10 is coupled to a computer 14 via an A/D converter 13 , if necessary. The transducer 10 comprises a measuring section 101 for making measurements, an operation section 102 having switches or the like, and a display section 103 for displaying measurement data.
[0004] The measuring operation in FIG. 7 will be described step by step. First, the sensor 11 is set ready for the measurement. After that, power is turned on to the transducer 10 . Next, the transducer 10 is placed in a setup mode, and various settings, such as the setting of upper and lower set values for the measurement range, the setting of alarm set points, the setting for temperature compensation, and the setting of response speed, are made from the operation section 102 of the transducer 10 . When the measurement setup of the transducer 10 is completed, the transducer 10 is placed in a measurement mode to start the measurement. Measurement data is transmitted from the sensor 11 and displayed on the display section 103 . Then, the transducer 10 is switched to a transmission mode to transmit the measurement data to the computer 14 for analysis.
[0005] In the prior art, analog transmission (DC 4 to 20 mA, etc.) or serial data communication such as RS-232C has been used as a method for transmitting the measurement data from the transducer to the computer.
[0006] In the case of analog transmission, the A/D converter 13 for converting the data into a digital signal must be provided as shown by dashed lines, thus requiring the use of an extra device before connection to the computer 14 .
[0007] In the case of serial communication using RS-232C, the A/D converter is not needed, but few instruments are equipped with RS-232C and, if equipped with RS-232C, such instruments are often expensive; for this reason, in the field of equipment for environmental analysis, process analysis, laboratory analysis, and industrial analysis, measuring systems using RS-232C are not prevalent (reference document 1).
[0008] Another method of transmission is one that uses the GPIB (General Purpose Interface Bus) interface. This interface allows a number of devices to be connected in a daisy chain on a single bus. However, equipment that uses this interface system is bulky, its volume being as large as 100 cm 3 or more, and requires the use of an independent power supply. GPIB ensures reliable data transmission by using a method called three-wire handshaking. While reliable data transmission can be achieved, GPIB is slow in such cases as when a setup operation and a measurement value read operation are repeated. (Reference document 2)
[0009] There is a high-speed version of GPIB, but this is intended for the transmission of large volumes of data (such as waveform data). Further, the cable length of GPIB is specified in the standard, and the expensive cable is usually rugged and bulky.
[0010] In the prior art, when processing a plurality of measurement data by computer, a plurality of arrays of sensors 11 a to 11 e , transducers 10 a to 10 e , and computers 14 a to 14 e have been arranged as shown in FIG. 8 , and the processing has been performed using a data management device 15 . As a result, the overall system becomes large, causing problems in terms of space and cost. (Reference document 3)
[0011] Furthermore, it has not been possible to control the transducer 10 from the computer 14 , and power has had to be supplied externally.
[0012] Reference document 1: Yokogawa Technical Report, Vol. 44, No. 1, 2000, pp. 19-24.
[0013] Reference document 2: http://www.ocs-1v.co.jp/LabVIEW/Sub3 — 5.htm
[0014] Reference document 3:
[0000] http://toyonakakeisou.com/02FA/01Keisoku/01Keisoku.htm
SUMMARY OF THE INVENTION
[0015] There are various limitations when using the prior art transducer 10 by incorporating it into other equipment, and these limitations have impeded the incorporation of the transducer into other equipment. For example, as measurement values are checked using a display meter or a digital display, and various settings and operations are performed using buttons or keys on the system, the transducer has had to be mounted in a surface section of an instrument. FIG. 9 shows an example in which the transducer 10 is mounted by cutting a panel 16 . Reference numeral 17 is a fixing device for fixing the transducer in place.
[0016] In this way, design freedom in terms of the incorporation of the measuring system has been greatly limited.
[0017] Further, when using a personal computer to process and analyze the data measured by the prior art measuring system, as the measurement value is output in the form of an analog signal in the prior art transducer, the signal has had to be converted into a digital signal for input to the personal computer. This has led to the problem that the accuracy of the measurement value decreases due to a conversion error associated with the signal conversion. Furthermore, this prior art system also has required the use of an A/D converter, resulting in an increase in cost.
[0018] There has also been the following problem. Conventionally, software has been provided to users in a general-purpose standardized form. On the other hand, user requests vary widely, and it is strongly requested by users that application software be made customizable, demanding that the source code of the special application software be disclosed. However, disclosure of the source code has involved difficult problems, as the disclosure means disclosing information including know-how. For such reasons, the user requests have not been adequately addressed.
[0019] It is an object of the present invention to solve the above problems associated with the prior art measuring system. More specifically, the invention is directed to the provision of a user-friendly system that ensures freedom for incorporating the measuring system into other equipment, reduces the conversion error associated with the signal conversion, reduces the cost of the A/D converter, and allows simultaneous processing of a plurality of data, while also addressing the user request for customization of application software.
[Means for Solving the Problems]
[0020] In view of the above technical problems, the system of the present invention is constructed so that measurement signals from various kinds of measuring instruments, for example, equipment for environmental analysis, process analysis, laboratory analysis, industrial analysis, or the like, can be directly coupled to a USB terminal of a computer, thereby making it possible to observe, record, and store the results of the measurements and to analyze the data. In this configuration, the transducer can be controlled by a control signal supplied from the computer via the USB cable, and power for the transducer can also be supplied from the computer. The invention thus achieves a system that processes a plurality of measurements simultaneously and analyzes the plurality of measurement data using a single computer.
[0021] According to a first mode of the present invention, there is provided a USB transducer comprising: input means for taking a measurement signal from a sensor; output means for transferring signals to and from an external computer via a USB cable; and signal processing means for processing the measurement signal as well as a signal transferred from the external computer.
[0022] According to a second mode of the present invention, the signal processing means according to the first mode includes: a CPU which receives the measurement signal from the sensor, converts the measurement signal into a digital signal, performs processing based on a command signal from the computer, and performs processing for converting the digital signal into measurement data; and a controller which converts the data into data ready for processing by the computer, and which converts the signal transferred from the external computer into a signal format ready for processing by the CPU.
[0023] According to a third mode of the present invention, the USB transducer according to the first or second mode is configured so that power for the USB transducer is supplied from the computer through the USB cable.
[0024] [Effect of the Invention]
[0025] Using the USB cable, signal transmission/reception and supply of power can be accomplished using a single cable connection. Thus, according to the present invention, not only can the measurement data be displayed on the computer display, but various settings for measurements can also be made on the computer while confirming the settings on the screen of the computer connected to the device of the present invention. Since power, for example, DC power (DC5V, 500 mA), necessary for the operation of the transducer is supplied from the computer, there is no need to provide a separate power supply.
[0026] Further, when incorporating the device (USB transducer) of the present invention into other equipment, since there is no need to provide setting/operation keys, display meter, digital display or the like on the device, and since the size of the device is small, no limitation is imposed when incorporating the device into other equipment, and thus the design freedom in terms of the shape and mounting of the device can be greatly enhanced.
[0027] As the signal that the device of the present invention outputs for transmission to the computer is a digital signal, the output of the device of the present invention is not converted and, therefore, provides a highly accurate measurement signal. There is also no need to provide an extra device such as an A/D converter.
[0028] Furthermore, most computers (both desktop and notebook types) currently sold on the market are fitted with terminals for USB connection, which is thus the most prevalent connection method.
[0029] In the case of the prior art transducer, there are cases where, depending on the quality of the power supply in the actual operating environment, the transducer is affected by external perturbations such as excessive noise, leading to malfunctioning of the transducer; on the other hand, when USB cable is used, stable operation of the transducer can be achieved because the quality of the power supplied from the computer is assured by the computer (USB interface) technical standard. Furthermore, the invention can achieve a system that makes a plurality of measurements simultaneously and performs data processing to analyze the plurality of measurement data using a signal computer.
BRIEF DESCRIPTION OF THE DRAWINGS
[0030] The above object and features of the present invention will be more apparent from the following description of the preferred embodiments with reference to the accompanying drawings, wherein:
[0031] FIG. 1 is a block diagram showing how a USB transducer according to the present invention is connected to a sensor and a computer;
[0032] FIG. 2 is a block diagram of the USB transducer according to the present invention;
[0033] FIG. 3 is a functional block diagram of the USB transducer according to the present invention;
[0034] FIG. 4 is a block diagram showing an arrangement for connection of USB transducers, sensors, and a computer when making a plurality of measurements;
[0035] FIG. 5 is a perspective view showing the external appearance of the USB transducer of the present invention;
[0036] FIG. 6A is a diagram showing connections for pH and ORP measurements using the USB transducer of the present invention;
[0037] FIG. 6B is a diagram showing connections for resistance/temperature measurement using the USB transducers of the present invention;
[0038] FIG. 7 is a diagram showing the configuration of a prior art transducer and its connections to a sensor and a computer;
[0039] FIG. 8 is a block diagram showing an arrangement for connection of USB transducers, sensors, computers, and a data management device when making a plurality of measurements according to the prior art; and
[0040] FIG. 9 is a perspective view for explaining the condition in which the prior art transducer is mounted in another equipment.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0041] Embodiments of the present invention will be described below with reference to the drawings.
[0042] FIG. 1 is a diagram showing a measuring system that uses a USB transducer according to the present invention. The output of a sensor 1 is connected to the USB transducer 2 whose output, in turn, is connected to a computer 4 by means of a USB cable 3 . A measurement signal from the sensor 1 is input to the USB transducer 2 , which then transfers the measurement signal to the computer 4 . At the same time, the computer 4 is configured to be able to set up the operation of the USB transducer 2 by sending the commands through the USB cable, check the measurement value, provide an instruction for computation, and process the data for analysis. Power for the transducer 2 is supplied from the computer 4 through the USB cable 3 .
[0043] FIG. 2 shows the configuration of the USB transducer 2 of the present invention. The USB transducer 2 includes an input connector 23 as an input means, a CPU 21 and a USB controller 22 as signal processing means for processing signals, and a USB terminal 24 as an output means.
[0044] The CPU 21 is connected to the USB controller 22 , and the USB controller 22 is connected to the USB terminal 24 . The USB terminal 23 is connected to the computer 4 via the USB cable 3 .
[0045] The measurement signal from the sensor 1 is input to the CPU 21 , transferred through the USB controller 22 and the USB terminal 23 , and sent to the computer 4 through the USB cable 3 . The signal from the computer 4 is transferred through the USB cable 3 and the USB terminal 23 and input to the USB controller 22 and the CPU 21 . In the figure, dashed lines indicate power supply lines over which the computer 4 supplies power to the USB transducer 2 .
[0046] The CPU 21 includes an A/D converter 211 , a computation circuit 212 , and a memory 213 . The A/D converter 211 is connected to the computation circuit 212 which in turn is connected to the memory 213 . The analog measurement signal from the sensor is converted by the A/D converter 211 into a digital signal which is supplied to the computation circuit 212 . The computation circuit 212 performs computation, for example, for converting the digital signal into measurement data by using the output of the A/D converter 211 and the data and program stored in the memory 212 , and stores the result of the computation in the memory 213 or supplies the result to the USB controller 22 . An identifier for identifying the transducer 2 , instrument set values, and firmware for the transducer are prestored in the memory 213 .
[0047] Each transducer has an identifier for uniquely identifying the transducer, and the identifier unique to the transducer 2 is prestored in the memory 213 . Using this identifier, the computer 4 can switch the mode between setup, measurement, and transmission for each individual one of transducers 2 a to 2 e when making different kinds of measurements (for example, pH and ORP measurements), and can make various settings and manage the measurement for each individual transducer.
[0048] The quantity to be measured is predetermined for each transducer 2 and, to make this distinction, an identifier indicating the quantity to be measured by the transducer 2 is prestored in the memory 213 .
[0049] The USB controller 22 converts the result of the computation received from the CPU 21 into a signal format that can be received by the computer 4 , and outputs the signal via the USB terminal 23 onto the USB cable 3 for transmission to the computer 4 . Conversely, the signal from the computer 4 is converted into a signal format that can be received by the CPU, and sent to the USB transducer 2 via the cable 3 and via the USB terminal 24 .
[0050] FIG. 3 is a block diagram showing a functional representation of the USB transducer 2 of the present invention. The USB transducer 2 includes at least an A/D converting means 26 and a functional means 27 . The functional means 27 comprises at least a time stamping means 271 and a command executing means 272 .
[0051] The A/D converting means 26 converts the analog measurement signal received from the sensor into a digital signal and is identical to the A/D converter 211 shown in FIG. 2 .
[0052] The time stamping means in the functional means 27 measures the measurement time 271 and appends a time stamp to the measurement data.
[0053] The command executing means 272 interprets a command received from the computer, and executes the command in the transducer 2 . Commands to be executed here include, for example, commands for alarm setting, measurement range setting, timer and other device setting, etc. and commands for performing computation for correcting the measurement data.
[0054] One feature of the USB transducer configuration according to the present invention is that all the functions and instructions necessary for controlling the USB transducer are predefined as commands (instruction words) for the user and that the means (command executing means) is provided for executing the commands. In the present invention, a command means a process to be executed in the transducer.
[0055] Usually, when controlling a device by using software, the contents of a command (describing the action and mathematical equation to be performed by the command) are directly written to a control program. In this case, the contents of the command (in particular, the mathematical equation and numeric value correcting means) may contain important know-how, and often, such contents cannot be disclosed to general users.
[0056] As a result, the user cannot create a control program specific to his use. If, for example, the mathematical equation is disclosed, unpredictable computation results can occur unless the user correctly understand the mathematical equation.
[0057] In view of this, the present inventors have devised a method in which instruction statements for setting conditions and the processing of a plurality of equations are predefined as single-line commands (instruction words) and the process to be executed by each particular command is stored in a memory within the transducer so that a control program can be executed by specifying the instruction word. With this method, an environment necessary for the construction of an application program can be provided to the user without disclosing the condition settings, important equations, and the details of computation.
[0058] As earlier described, there are two kinds of commands, one concerning transducer setting and the other describing the details of computation. In practice, the command executing means is configured to store in a program area within the memory 213 a program that executes an instruction in response to each particular command, and to cause the computation circuit 212 to execute the command.
[0059] In the above configuration, when a command is sent to the USB transducer 2 from the computer 4 , the command is executed using the computation means 212 and the program stored in the memory of the transducer 2 .
[0060] Examples of transducer commands for pH measurement are shown below.
[0061] 1. Examples of condition setting commands
[0062] OFFSET:
[0063] Set electromotive force corresponding to pH=7, and store the set value in memory.
[0064] CRACK:
[0065] Set electrode crack detection function and store the setting in memory.
[0066] 2. Examples of computation commands
[0067] CAL:
[0068] For example, a true value C which is a value effective as measurement data is obtained by subtracting correction value B, an offset value, from the measurement value A measured by the sensor 1 ; here, when a user command CAL for true value calculation is issued from the computer 4 , the operation C=A−B is performed in the USB transducer 2 .
[0069] TEMP_COMP:
[0070] This command sets the sample solution temperature compensating function for the pH value, and stores the setting in memory. The sample solution temperature compensating function compensates for the pH-temperature characteristics of the sample solution, and the pH value is compensated for temperature in accordance with the following equation.
[0071] pH value after compensation=Raw pH value−(Solution temperature−25° C.)×Solution temperature compensation coefficient
[0072] In the above equation, the solution temperature compensation coefficient represents the amount of change of the pH value for a temperature change of 1° C. This coefficient value varies from one sample solution to another.
[0073] Next, an operation will be described referring to FIG. 2 . First, when the USB transducer 2 of the present invention is connected to the computer 4 via the USB cable 3 , operating power is supplied to the transducer 2 which is thus started up. Thereupon, the transducer identifier and the sensor identifier are automatically sent to the computer 4 . Next, the USB transducer 2 is placed in a setup mode by a command from the computer 4 , and receives the various setting commands from the computer 4 to make necessary settings, thus becoming ready for measurement.
[0074] When the setup for the measurement is completed, the USB transducer 2 is placed in a measurement mode by a command from the computer 4 . In this mode, the sensor 1 makes the prescribed measurement. The signal measured here is an analog signal, which is sent to the USB transducer 2 where the analog signal is converted by the A/D converting means 22 into a digital signal. Further, in the CPU 21 , using the data and program prestored in the memory 213 the computation means 212 corrects the digital signal for changes in temperature and for individual differences of hardware by performing computation under the conditions prespecified by the user, and outputs the final measurement data. That is, the A/D-converted digital signal is based, for example, on the voltage of the electromotive force generated from the sensor and, when measuring the pH, the digital signal is converted to the pH value corresponding to the voltage value, and computation for correction, etc. is performed. On the other hand, the time stamping means 271 measures the measurement time, and appends to the digital signal a time stamp that indicates the time of the measurement ( FIG. 3 ).
[0075] The signal is then output from the USB transducer 2 , passes through the USB cable 3 , and is input to the computer 4 .
[0076] When the user corrects the measurement value, for example, the pH value, by temperature compensation, the TEMP_COMP command is sent to the transducer 2 from the application software running on the computer 4 . The computation means 212 in the CPU 21 then recognizes the TEMP_COMP command from among the commands prestored in the memory 213 , and performs the specified computation (action) to execute the temperature compensation in accordance with the previously made setting. Likewise, when any particular command is sent to the transducer 2 from the application software running on the computer 4 , the command is recognized and the specified function or computation is executed in the transducer 2 . The result of the execution is stored in the memory 214 or sent to the computer 4 via the USB controller.
[0077] FIG. 4 shows a configuration in which a plurality of transducers 2 a to 2 e are connected to one computer 4 . Using the transducer identifiers earlier described, the computer 4 can automatically identify the plurality of connected transducers 2 a to 2 e and manage the respective measurement data. In the illustrated example, five transducers are connected. In the preferred embodiment of the invention, up to 12 transducers, for example, can be automatically identified. The transducers can be handled without having to be aware of the type of sensor (the quantity to be measured). The transducer identifiers may be used in combination with the sensor identifiers to further enhance the reliability with which the quantities to be measured are identified.
[0078] FIG. 5 is a perspective view showing the external appearance of the USB transducer 2 , and reference numeral 23 indicates an input means via which a signal from the sensor is input, i.e., a connector to which a signal line from the sensor is connected. On the opposite side from the connector 23 , there is provided an output means of the USB transducer 2 , that is, a connector (USB terminal 24 ) for connecting to the USB cable (this connector is not shown here, as it is a connector well known to any person skilled in the art).
[0079] FIGS. 6A and 6B show application examples that use the transducers of the present invention.
[0080] In FIG. 6A , two USB transducers ( 2 a and 2 b ) according to the present invention are used to measure the measurement data received from a pH sensor 1 a and an ORP (Oxidation Reduction Potential) sensor 1 b . The input terminals of the USB transducers 2 a and 2 b are connected to the pH sensor 1 a and the ORP sensor 1 b , respectively. The output terminals are connected to the computer 4 via respective USB cables 3 a and 3 b and via a hub 5 .
[0081] The USB transducer 2 a connected to the pH sensor 1 a is a dedicated transducer for the pH sensor, and the USB transducer 2 b connected to the ORP sensor 1 b is a dedicated transducer for the ORP sensor. Accordingly, the computer 4 can automatically identify the type of each USB transducer.
[0082] In the figure, the measurement signal from each sensor, which includes temperature data, is sent to the corresponding USB transducer through four lines. In this configuration, the pH of the solution, the temperature of the solution, and the ORP measurement data taken from the solution whose ORP is measured are simultaneously read into the computer 4 and displayed on the display of the computer 4 . The illustrated example has shown as an example the configuration in which two sensors, the pH sensor and the ORP sensor, are connected, but it will be appreciated that only one sensor may be used. It is also possible to use a dissolved oxygen (DO) sensor as the sensor. In that case, a USB transducer dedicated for the dissolved oxygen (DO) sensor is used, as a matter of course. Here, as data measured by the dissolved oxygen (DO) sensor is influenced by solvent temperature and chloride ion concentration, compensation buttons for selecting solvent temperature and chloride ion concentration compensation methods to compensate for the data can be added on the display (not shown) of the computer 4 .
[0083] With the traditional RS-232C interface, because of its specification, it has been difficult to read two or more measurement signals simultaneously into a computer. Further, while a system similar to the one of the present invention can be constructed using a GPIB interface, the interface and the cable are generally expensive and, if a plurality of data are to be captured simultaneously and displayed on the computer, a special program for that purpose has had to be created.
[0084] According to the present invention, as the plurality of USB transducers in accordance with the present invention can be easily connected to one computer using a commercially available USB hub, and as each transducer can be automatically identified at the computer end and each measurement data can be automatically measured, displayed, and stored, there is no need to create a special program for that purpose. As the time of the measurement is appended to each measurement data, the variation of the data can be automatically displayed. Further, the computer can analyze the measurement data by effectively using the time data. Furthermore, as the power for the USB transducer is supplied from the computer, and the transducer body is small for this type of transducer, the space required for conducting an experiment can be saved. In the experiment conducted here, a computer, two USB transducers, a USB hub, a pH sensor, and an ORP sensor were arranged on a desk measuring 30 cm by 60 cm. After connecting the USB cables, the three parameters, i.e., the pH, the temperature of the pH solution, and the ORP were read at intervals of one second, and the parameters were able to be displayed simultaneously on the display (not shown) and recorded.
[0085] FIG. 6B shows an example in which a specimen resistance/temperature measuring instrument is constructed using two USB transducers ( 2 a and 2 b ) of the present invention dedicated for voltage and temperature sensors, respectively. The resistance/temperature measurement here means measuring a change in the resistance value of the specimen with respect to a change in temperature.
[0086] In FIG. 6B , reference numeral 6 designates the test specimen for the resistance/temperature measurement. This is, for example, a rectangular specimen measuring 1 cm in length, and 5 mm in width 3 mm in thickness (top view). Vapor deposition electrodes 6 a and 6 b are respectively formed on the upper and lower ends of the specimen 6 , and two vapor deposition electrode bands 6 c and 6 d , each encircling the specimen 6 , are formed at two positions spaced apart in the height direction. This specimen 6 is placed in a thermostatic chamber 7 , and a constant current source 9 is connected to the electrodes 6 a and 6 b . A temperature sensor 8 is placed inside the thermostatic chamber 7 .
[0087] The first USB transducer 2 a is connected to the electrode bands 6 c and 6 d of the specimen 6 via cable 10 a and 10 b , and the second USB transducer 2 b is connected to the temperature sensor 8 via cables 11 a and 11 b . The first and second USB transducers are dedicated USB transducers for the voltage and temperature sensors, respectively. Their outputs are connected to a hub 5 via the respective USB cables 3 a and 3 b , and the output of the hub 5 is connected to the computer 4 via a cable 12 .
[0088] The resistance and temperature of the specimen 6 are measured while supplying, for example, a direct current of 1 μA to 1 A from the constant current source 9 in the direction directed from the electrode 6 a toward the electrode 6 b.
[0089] For the resistance/temperature measurement of the specimen 6 , the temperature sensor 8 is placed in close proximity to the specimen 6 , and the terminal voltage between the two vapor deposition electrode bands 6 c and 6 d of the specimen 6 is transmitted to the second USB transducer 2 b and, via the USB hub 5 , on to the computer 4 which displays the voltage on the display (not shown) connected to the computer 4 .
[0090] The type of each USB transducer (in this case, the dedicated USB transducers for the voltage and temperature sensors) is automatically identified by the computer, and the measurement data received from the first USB transducer 2 a and second USB transducer 2 b are automatically and periodically measured, displayed, and stored in a memory (not shown) by the computer. In the example of the USB transducer that the inventor fabricated in accordance with the present invention, the measurement was successfully made with a particular value within the range of −100 V to 100 V, for example, with 50 V, and the accuracy of the measurement was 1 mV.
[0091] On the other hand, the level of the temperature measurement signal that the second USB transducer outputs differs depending on the type of the temperature sensor 8 (for example, when the temperature sensor is a thermocouple sensor, the measurement temperature range and the accuracy vary depending on the type of the thermocouple (B, R, S, N, K, etc.); therefore, voltage versus temperature calibration must be done for each type of sensor. For this purpose, a set button for selecting the type of thermocouple can be added on the screen of the computer display.
[0092] Further, by clicking on an electrode crack detection function on the computer, a fault condition can be detected immediately when a break occurs in the thermocouple.
INDUSTRIAL APPLICABILITY
[0093] In the field of equipment for environmental analysis, process analysis, laboratory analysis, and industrial analysis, the applicability of the present invention is enormous, because measurement data can be directly handled by a computer and because a plurality of data can be processed simultaneously. Furthermore, as the transducer of the present invention is compact in construction and does not require the provision of a dedicated power supply, design freedom when incorporating the transducer into a system is enhanced, which greatly facilitates the construction of the system. It has been verified as described above that the present invention is particularly useful for applications where the transducers are connected to a pH sensor, an ORP sensor and voltage and temperature sensors.
CROSS-REFERENCE TO RELATED APPLICATION
[0094] This application claims priority of Japanese Patent Application Number 2006-031646, filed on Feb. 8, 2006. | The present invention is directed to the provision of a user-friendly system that ensures freedom for incorporating the measuring system into other equipment, reduces a conversion error associated with signal conversion, reduces the cost of an A/D converter, and allows simultaneous processing of a plurality of data. A USB transducer according to the present invention comprises: an input section which receives a measurement signal from a measuring device; a controller which converts measurement data into digital data and further converts the digital data into data ready for processing by a computer; and an output section having a USB connection terminal for outputting the data generated by the controller to the computer by using a USB cable, and for receiving a control signal from the computer. | 35,828 |
BACKGROUND OF THE INVENTION
[0001] This invention relates to a packing for an injector device for the placement of a subcutaneous infusion set on a patient.
[0002] Medical needles are widely used in the course of patient treatment, particularly for delivery of selected medications. In one form, hollow hypodermic needles are employed for transcutaneous delivery of the medication from a syringe or the like, an insertion needle used in conjunction with an injector device is employed for transcutaneous placement of a soft and relatively flexible tubular cannula, followed by removal of the insertion needle and subsequent infusion of medical fluid to the patient through the cannula.
[0003] It is often necessary for a patient to transcutaneously place the medical needle himself. Diabetic patients for example frequently place a subcutaneous infusion set with a cannula for subsequent programmable delivery of insulin by means of a medication infusion pump.
[0004] Some patients are reluctant or hesitant to pierce their own skin with a medical needle, and thus encounter difficulties in correct needle placement for proper administration of the medication. Such difficulties can be attributable to insufficient manual skill to achieve proper needle placement or alternately to anxiety associated with anticipated discomfort as the needle pierces the skin. This problem can be especially significant with medications delivered via a subcutaneous infusion set, since incorrect placement can cause kinking of the cannula and resultant obstruction of medication flow to the patient. Cannula kinking can be due to infusion set placement at an incorrect angle relative to the patient's skin, and/or needle placement with an incorrect force and speed of insertion.
[0005] In relation to the known devices several different problems are recognized. Either the packing is compact and easy to handle but do not leave room for storage of extra equipment or accessories which is necessary or nice to have when applying the infusion set and protection of the insertion needle, or the packing can comprise extra equipment or accessories but is difficult to handle e.g. because it has a separate needle cover attached to the injector device which needle cover has to be removed before use.
[0006] The invention of the present application indicates a solution to these problems.
[0007] In order to provide the patient with a system comprising an injector device, an infusion set and necessary accessories such as tubing and connection (hub) for e.g. a pump or a reservoir which system can assure correct, easy and safe insertion of the infusion set, it is an advantage if the injector device combined with the infusion set and all other necessary components are delivered to the patient in one packing which is easy to gain access to and where the system is in a ready-to-use form making it uncomplicated for the patient to remove the injector from the sterile packing, connect the tubing of the infusion set to e.g. a pump or a reservoir and inject the infusion device, without having to interconnect any components of the system whether that could be attaching the infusion set to the injector or connecting the tubing to the infusion part.
[0008] An example of injector devices which can be enclosed in the packing is disclosed in WO03/026728, incorporated by reference herein.
[0009] The present invention is aimed at providing a packing for an injector device, which allows for protecting the sharp-pointed needle which is used to penetrate the patient's skin and allows for including tubing and large or heavy pieces such as a hub beside the injection device inside the packing. The present invention also aims at providing a packing which allows for the injection device to take at least two positions inside the packing, in a first position the injection device is secured to the packing and in a second position it is possible to remove the injection device from the packing.
SUMMARY OF THE INVENTION
[0010] The invention concern a packing inside which an injector device combined with an infusion set and at least one insertion needle can be kept under sterile conditions which packing comprises at least
a first part made of a material which can not be penetrated by an insertion needle, a second part which is attached to the first part before use in such a way that the conditions inside the packing remains sterile, a first storage room storing the injector device combined with an infusion set and an insertion needle and characterized in that the first part provides a further storage room isolated from the insertion needle.
[0014] The storage room is an open room defined by the walls of the first part of the packing and by a surface of the combined injector device. The extra storage room can be used for keeping equipment such as fittings for external equipment, connectors attached to the tubing from the infusion device etc. under sterile conditions, while at the same time protecting the insertion needle which will normally be <0.5 mm in outer diameter, preferably <0.3 mm in outer diameter. These very thin insertion needles are normally used when insertion is performed with an injector device as the injector device assures that the insertion needle penetrates the skin of the patient in a correct angle without twisting or bending the insertion needle.
[0015] In one embodiment of the invention the further storage room is adjacent to the proximal side of the infusion set and the further storage room has at least one wall provided by a needle cover extending from the inner surface of the first part toward the proximal side of the infusion set thereby isolating the insertion needle. In this embodiment the needle cover is integrated with the cover isolating the needle/cannula side of the injector device from the surroundings.
[0016] In a second embodiment of the invention the further storage room is adjacent to a non-proximal side of the insertion device. A non-proximal side is a distal side of the injector device combined with the infusion set and the at least one insertion needle. In this second embodiment there is no needle cover isolating the needle/cannula side of the injector device from the surroundings, the further storage room is formed by the first part of the packing and e.g. a distal surface of the combined injector device.
[0017] In the second embodiment of the invention the further storage room is preferably adapted for at least partly holding the injection device after use, this can be done by providing the further storage room with restrictions which restrictions will secure the injection device to the inside of the first packing after use.
[0018] Preferably the first part of the packing is constructed with a bottom part and walls standing upright form the bottom part and forming a rim opposite the bottom part and the second part comprises one piece of material which can be secured to the rim.
[0019] In a preferred embodiment the walls, seen from a sectional view through upright standing material, form at least two sections each formed as a partial circle with at least two centres C 1 and C 2 and the centres C 1 and C 2 are placed with a distance D between them. Preferably the radius of the two partial circles, R 1 and R 2 , are not identical, R 2 <R 1 .
[0020] In a preferred embodiment the section with the centre C 1 has a radius R 1 large enough to hold the injector device without restricting removal of the device from the packing, and preferably this section should be large enough to hold the injector device wrapped with at least one layer of infusion tubing.
[0021] In a specially preferred embodiment the section with the centre C 2 has a radius R 2 large enough to hold the housing of the injector device, and preferably the section with the centre C 2 has restrictions which secure the injector device to the first part of the packing. These restrictions should prevent the used injection device to move out of the first part of the packing in a direction parallel with the walls of the first part of the packing. Also such restrictions could prevent the used injection device to move between the section with centre C 1 and the section with centre C 2 .
[0022] The invention also concerns a combined injector device comprising an infusion set, at least one insertion needle, a housing, the injection device is releasably connected to the infusion set and the infusion set is connected to an infusion tubing, where the infusion tubing is placed outside the housing of the injector device during storage under sterile conditions. As it is preferred to remove the tubing from the packing before the injection device is removed from the clean packing, it is more efficient to place the tubing outside the housing of the injection device as this makes the tubing accessible. Preferably the infusion tubing is coiled around the outer surface of the housing during storage.
[0023] In a more preferred embodiment the invention concerns an injector device combined with an infusion set and an insertion needle which combination before use is kept under sterile conditions in a packing comprising at least
a first part made of a material which can not be penetrated by an insertion needle, a second part which is attached to the first part before use in such a way that the conditions inside the packing remains sterile, and the injector device comprises a housing and is releasably connected the infusion set which infusion set is connected to an infusion tubing,
characterized in that the infusion tubing is placed between the outer surface of the housing of the injector device and the inner surface of a first part of the packing during storage.
[0027] In a more preferred embodiment the invention concerns an injector device assembly for transcutaneously placing a hollow cannula of a subcutaneous infusion set through the skin of a patient where the injector device is releasably connected to the infusion set ( 14 ) during storage, and where the injector device comprises:
a device housing, a plunger slidably received within the device housing for movement between an advanced position and a retracted position, an insertion needle is either secured to the plunger for receiving and supporting the cannula of the subcutaneous infusion set or insertion needle is constituted by the cannula, the infusion set, which is releasably connected to the plunger, is in a position oriented for transcutaneous placement of the cannula upon movement of the plunger from the retracted position to the advanced position, a drive for urging the plunger from the retracted position toward the advanced position to transcutaneously place said cannula of said subcutaneous infusion set received on said insertion needle,
and the infusion set comprises:
a housing connected to an infusion tubing by a suitable connector, wherein the infusion tubing is positioned close to the outer surface of the housing of the injector device during storage, and preferably the infusion tubing is coiled wholly or partly around the housing of the injector device, and more preferred the outer surface of the housing is provided with guiding or positioning means for the tubing.
[0032] One purpose of the packing according to the present invention is to form a closed shell around the injector and the infusion set in order to prevent the device from being polluted with micro organisms. A second purpose is to protect the injection needle, which could be the cannula, from impacts from the surroundings as the cannula/injection needle is very thin and delicate, and also to protect the surroundings from the injection needle, especially when the insertion needle has been used and has to be disposed of. A third purpose is to make it possible to include a whole system for injecting an infusion set and connecting this set to a device such as a pump or a reservoir in a packing in a ready-to-use state.
BRIEF DESCRIPTION OF THE DRAWINGS
[0033] The accompanying drawings illustrate the invention.
[0034] FIG. 1 is a perspective view of a known infusion device suitable for use with an injector device, and
[0035] FIG. 2 shows in an exploded view a known embodiment of an injector device assembly wherein the plunger has an insertion needle secured thereto,
[0036] FIGS. 3 a and 3 b show in a perspective view the known injector device of FIG. 1 with the plunger in the advanced position,
[0037] FIGS. 4 a and 4 b show in a perspective view the injector device of FIG. 2 with the plunger in the retracted position,
[0038] FIGS. 4 c - 4 e show views similar to FIGS. 3 a , 4 a and 4 b with part of the housing being cut away,
[0039] FIGS. 5 A and B show respectively a view of the inner surface and a view of the outer surface of a first part of a packing of one embodiment according to the invention,
[0040] FIG. 6 shows a view of a first part of a packing of a second embodiment according to the invention,
[0041] FIG. 7 shows a three-dimensional view of the second embodiment of FIG. 6 ,
[0042] FIG. 8 shows a housing of an injector device according to the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0043] FIG. 1 shows an example of an infusion set 14 suitable for use with an injector device. The infusion set 14 includes a housing 3 with an internal chamber (not shown). The internal chamber receives medication via infusion tubing 113 which may be detachably connected to the housing 3 by any suitable connector 7 . The base 24 of the housing 3 may be a flexible sheet of a woven material secured to the housing 3 such as by means of an adhesive and carrying an adhesive covered by a release sheet 14 ′ which is removed to expose the adhesive prior to placement of the infusion set. The infusion set 14 has a protruding soft and flexible cannula 26 , which communicates with the internal chamber. An internal passage which is sealed by a sealing membrane 4 and which is penetrated by the insertion needle of the injector device extends through the housing opposite the cannula 26 .
[0044] FIG. 2 shows in an exploded view a known embodiment of an injector device assembly.
[0045] FIGS. 3 and 4 show the same embodiment in different views and positions.
[0046] The packing of the injector device 310 includes a housing 328 and respective removable covers 342 , 394 . The cover 342 has a hollow for accommodating a part of an insertion needle 312 when the cover 342 is secured to the housing 328 , such as by snap engagement with the rim 309 of the housing 328 . The cover 342 , the housing 328 , a plunger 330 and a drive with a spring for advancing the plunger 330 to the advanced position can be made of plastics while the cover 394 may be a flexible foil secured to the housing 328 by an adhesive. Preferably, the covers 342 , 394 serve as bacterial barriers, the flexible foil 394 being of medical paper. An insertion needle 312 is preferably secured in a stable manner to the plunger 330 of the injection device, such as by press-fitting, the plunger 330 having a narrow central passage wherein an end of the insertion needle 112 is lodged. The plunger 330 and the drive may be formed integrally as a single component in a molding process.
[0047] The ring-shaped housing 328 is flexible in the sense that the application of a manual force against diametrically opposed depressions 303 of fingertip size will give rise to a slight deformation of the housing 328 such that it assumes a slightly oval shape when viewed from above for bringing about a release of the plunger in the retracted position and cause a spring-loaded movement of the plunger 330 towards the advanced position, as will be explained. For maintaining the plunger 330 in the retracted position the housing 328 is provided with two opposed ledges 366 . Moreover, the housing 328 is provided with opposed dovetail projections 301 extending along the same general direction as the insertion needle 312 and adapted to connect with complementary recesses in the aforementioned spring, to secure the spring in relation to the housing 328 .
[0048] The plunger 330 generally includes a head 332 , a hub 331 and, opposite the head 332 , an enlarged gripping portion 331 ′ which allows a user to manually pull the plunger 330 to a retracted position. The head 332 normally carries a marking M representing the place where the 113 tubing exits the infusion set 314 located there under whereby the user can check the orientation of the tubing after placement of the infusion set. The head 332 moreover has a recess 332 ′ for accommodating the infusion set 326 with cannula 326 through which the insertion needle 312 extends, the infusion set 314 preferably being maintained in position by frictional engagement of the insertion needle 312 with an inside surface of the infusion set 314 . The plunger 330 has two opposed rigid walls 306 extending radially outwardly from the hub 331 . The walls 306 extend in the axial direction of the device 310 , i.e. in the same general direction as the insertion needle 312 , and are connected to the aforementioned spring. Moreover, as best seen in FIG. 3 d , the walls 306 each carry a lateral projection 307 with a finger 358 which is releasably locked in engagement with a corresponding one of the ledges 366 of the housing 328 by snap action in the retracted position of the plunger 330 . The depressions 303 preferably being offset with respect to the ledges 366 by about 90° will cause the opposed ledges 366 to move apart when the aforementioned manual force is applied and the housing 328 assumes an oval shape, thereby bringing the finger 358 on each wall 306 out of engagement with the corresponding ledge 366 . For retaining a proximal part of the tubing 113 (not shown) which is wound around the plunger 330 , wall 306 has a groove G best seen in FIGS. 4 c and 4 d sized to receive a small length of the tubing 113 and to prevent the infusion set 314 from being inadvertently pulled away from the plunger 330 by the user when the tubing is unwound for connection with a medical fluid supply.
[0049] The drive which acts to drive the plunger 330 from the retracted position towards the advanced position when the fingers 358 are disengaged comprises a spring including four thin and flexible plastics strips, of which two opposed strips 336 A extend about halfway around the plunger 330 at the level of the gripping portion 331 ′ while two other opposed strips 336 B extend about halfway around the plunger 330 at the level of the head 332 , as viewed in the advanced and unbiased position of the plunger shown in FIGS. 2 and 3 a - e . One end 336 ′ of one of the strips 336 A and one end 336 ′ of one of the strips 336 B is rigidly connected to one of the walls 306 , while one end 336 ′ of the other one of the strips 336 A and one end 336 ′ of the other one of the strips 336 B is rigidly connected to the other one of the walls 306 . Preferably, the strips 336 A and 336 B are integrally connected with the walls 306 in a molding process where the plunger 330 and the spring formed from the strips 336 A and 336 B is formed in one molding operation.
[0050] The spring also comprises two rigid opposed rigid walls 302 that extend in the axial direction of the device 310 and that are each rigidly connected with the second end 336 ″ of one of the strips 336 A and the second end 336 ″ of one of the other strips 336 B. The rigid walls 302 are preferably integrally connected with the strips 336 A and 336 B at the second end thereof. The walls rigid 302 each have an axially extending recess 305 which is complementary with the dovetail projection 301 on the housing 328 . When the plunger 330 with the spring is mounted within the housing 328 the dovetail projection 301 is slid into the recess 305 by axial movement; by selecting proper dimensions of the dovetail projection 301 , and possibly also by performing this operation at a predetermined temperature, a press-fit may result that prevents subsequent removal of the plunger 330 . Alternatively, or additionally, the plunger 330 may be secured using glue, or using a welding process. The two rigid walls 302 of the spring also comprise a respective projection 308 with a lower surface which in the advanced position of the plunger 330 is essentially coplanar with the rim 309 of the housing 328 . The projections 308 include a clip-like retainer C for securing a distal part of the tubing 113 wound around the plunger 330 , thereby maintaining the tubing in position until unwound by the user.
[0051] As will be understood, the walls 302 are fixed in relation to the housing 328 , and the strips 336 A and 336 B, being thin and flexible, define the parts of the spring that undergo a change in shape upon retraction of the plunger 330 and that through this change of shape generate the force acting on the plunger 330 via the connections at the ends 336 ′ and required to advance the plunger 330 to the advanced position upon disengagement of the fingers 358 . The shape of the strips 336 A and 336 B in the deformed condition when the plunger 330 is held in the retracted position is shown in FIGS. 4 a - d . The connection between the strips 336 A, 336 B and the walls 302 , 306 being rigid, in the sense that bending moments arising in the strips 336 A, 336 B upon retraction of the plunger 330 are transferred to the walls 302 , 306 , brings about a deformation of the strips 336 A, 336 B as shown.
[0052] It will be understood that the resiliency of the spring is generally defined by the elastic properties of the flexible strips 336 A, 336 B which should be selected such that the drive is capable of advancing the plunger 330 to the advanced position at least once, following retraction. The spring would normally allow the piston to be retracted several times, and provide the required force for subsequently advancing the plunger 330 . However, the device being normally a disposable unit requires the spring to be formed with the capability to only a limited number of times advance the plunger 330 at one given speed, and the spring need not be capable of returning the plunger to the exact original position after several times of use.
[0053] As seen best in FIG. 2 , the two strips 336 B each carry a wall member 304 which provides support for a tubing (not shown) connected to the infusion set 314 and wound around the plunger 330 in the annular space 315 between the plunger 330 and the housing 328 .
[0054] In this embodiment the housing 328 constitutes the packing and this necessitates that the tubing 113 is wound around on the inside of the housing 328 in order for the tubing to be protected by the packing.
[0055] FIGS. 5 A and B shows an embodiment of a first part 1 of the packing according to the invention seen from the side being adjacent to the insertion needle, this embodiment has one storage room which isolates the insertion needle 9 a and one storage room for accessories 9 b . In this embodiment the first part 1 replaces the removable cover 342 of the known injection device and the second part is constituted by the housing 328 and the second removable cover 394 . The cover 342 is made of a relatively hard material and has a hollow for accommodating the insertion needle 312 when the cover 342 is secured to the housing 328 , but the cover is only intended to protect the insertion needle 312 from impacts and actions coming from the outside of the packing. In order to protect the delicate insertion needle 312 from actions coming from the inside of the packing, e.g. actions origination from accessories to the combined injection system laying unsecured in the sterile storage room next to the insertion needle 312 , the first part 1 is provided with a needle cover 8 extending from the inner surface 7 of the first part 1 and completely surrounding the insertion needle 312 . In this embodiment the second storage room 9 b which is isolated from the insertion needle 312 has the form of a circular band with a vacant circular centre in which the insertion needle 312 , 26 is positioned when the first part 1 of the packing is joined to the injector device 310 , but the needle cover 8 could also have the form of a wall being connected at two positions to the inner surface 7 of the first part 1 of the packing as illustrated in FIG. 5 B.
[0056] The needle cover 8 is preferably made of a continuous sheet of material providing a continuous protective wall for the insertion needle 312 but the needle cover 8 can be made of a material different from the first part 1 of the packing and the needle cover 8 can also be made as a non-continuous wall e.g. be made of upright standing posts or the like which provides for a non-continuous wall but although non-continuous the wall continues to protect the insertion needle 312 against the unit or units being stored between the inner walls 7 of the first part 1 of the packing and the insertion needle 312 as long as the openings in the needle cover 8 are small enough to prevent contact between the unsecured unit(s)/accessories and the insertion needle 312 .
[0057] FIG. 5 C shows the first part 1 of the packing seen from the outer side i.e. the non-sterile side of the packing.
[0058] FIG. 6 shows a first part 1 of a packing according to the invention, the first part 1 of the packing consist of a rim 2 d and a shaped hollow comprising a bottom part 2 a , 2 b and a wall part 2 c with an inner surface 7 . In order to provide the packing with an adequate steadiness, the bottom part is preferably constituted with a plurality of hollow 2 a and elevated 2 b areas. In FIG. 5 the bottom part is provided with four hollows 2 a forming a cross-like elevated part 2 b . The elevated part 2 b extends along the line A-A and along the lines from C 1 -B on both sides of the rim 2 d.
[0059] The first part 1 of the packing covers the cannula side of the injection device 310 , 310 ′ inside the packing and is made of a relatively hard material such as polypropylene (PP) or polyethylene (PE) or another material which cannot be penetrated by the injection needle. The relatively hard material will protect the injection needle against impacts from the surroundings and also the surroundings will be protected against the injection needle 312 . The injection needle can either be a sharp needle 312 unreleasably connected to the injector device 310 , 310 ′ or it can be the cannula 26 , 326 of the infusion set 14 when the cannula is constructed of a hard material. A second part of the packing (not shown) of this embodiment covers the opening of the first part 1 of the packing which opening is formed of the rim 2 d and turned away from the injection needle 312 , 26 . This means that the second part of the packing does not need to protect the insertion needle and can be made of a soft material which is e.g. glued or welded to the rim 2 d of the first part 1 of the packing.
[0060] When seen from the rim side, which will also be referred to as the top side, the packing of this embodiment has the form of two partial circles with different diameter, D 1 and D 2 . The two circles are larger than half their full size which means that the line B-B where they meet forms the narrowest part of the shape formed by the rim 2 d . No matter which forms the two sections may have it will be preferred to provide the space shaped by the walls 2 c with a reduced cross-section indicated with a line (B-B) in FIG. 5 . The center of the largest partial circle is marked with C 1 and the center of the smallest partial circle is marked with C 2 and the position where the line B-B crosses the line A-A is marked with O. The line B-B will in this embodiment always be perpendicular to the line A-A and cross the line A-A at a position between the two center markings C 1 and C 2 . The distance D between the two center markings C 1 and C 2 is in the figure named d C1-O-C2 .
[0061] In this embodiment the distance between the inner surface of the walls 2 c at the line B-B is almost the same as the outer diameter of the housing 328 of the injector device 310 , 310 ′, preferably the distance between the inner surface of the walls 2 c at line B-B is slightly smaller than the housing 328 of the injector device and the walls 2 c have a certain flexibility which will make it possible to force the housing 328 of the injector device 310 , 310 ′ from the circle part with the largest diameter to the circle part with the smallest diameter and then lock the injector device 310 , 310 ′ in this position as the flexibility of the walls 2 c of the packing will prevent the injector device from slipping back into the circle part with the largest diameter.
[0062] In a preferred embodiment the device has the following measures:
[0000] Outer radius of the housing 328 incl. guiding means 5 =57 mm
Outer radius of the housing 328 excl. guiding means 5 =55 mm
d C1-B =R 1 =30.2 mm
d C2-B =R 2 =27.7 mm
D=d C1-O-C2 =20.0 mm
d C1-O =13.74 mm
d B-O =√{square root over (30.2 2 −13.74 2 )}=26.89 mm
d B-B =2*d B-O =53.77 mm (distance between inner walls at line B-B)
[0063] The first part 1 of the packing can be provided with means for locking the injector device 310 , 310 ′ to the inside of the packing of the circle part with the smallest diameter. This can be done in a simple way by extending the rim 2 d of the circle part with the smallest diameter either partly, i.e. by forming protrusions extending inwardly from the rim 2 d toward the center C 2 , or as a whole i.e. the whole rim is extended toward the center C 2 thereby decreasing the diameter of the partial circle part at the rim 2 d level. Which solution is the most appropriate would depend on the material used to make the first part 1 of the packing and the rim 2 d of the packing, generally the more stiff and steady the material is the fewer protrusions or the smaller protrusion area will be needed to detain the injector device inside the packing.
[0064] The height H representing the total height of the first part 1 of the packing comprising both the walls 2 c and the bottom part 2 a , 2 b should be deep enough to surround and protect the insertion needle.
[0065] The area of the packing placed closest to—and facing—the insertion needle, in this embodiment the central part of the packing along the line A-A, will have a height H sufficient to enclose and protect the insertion needle whether the injection device is placed in the partial circle with the smallest or the largest diameter.
[0066] FIG. 6 shows a three-dimensional view of the embodiment from FIG. 5 .
[0067] FIG. 7 shows an embodiment of an injection device which can be packed in the embodiment of the packing described in FIGS. 5 and 6 . In this embodiment guiding means 5 are placed on the outer surface 6 of the housing 328 .
[0068] Like the known device shown if FIG. 2-4 the injection device 310 ′ comprise a ring-shaped housing 328 which is flexible in the sense that the application of a manual force against diametrically opposed depressions 303 of fingertip size (Only one is shown) will give rise to a slight deformation of the housing 328 such that it assumes a slightly oval shape when viewed from above for bringing about a release of a plunger in the retracted position and cause a spring-loaded movement of the plunger towards an advanced position. For maintaining the plunger in the retracted position the housing 328 is provided with two opposed ledges 366 . The housing 328 is also provided with opposed dovetail projections 301 extending along the same general direction as the insertion needle and adapted to connect with complementary recesses in the spring, to secure the spring in relation to the housing 328 . The plunger can be as described above and shown in FIGS. 2 , 3 and 4 .
[0069] As the packing will isolate the injector device 310 ′ from the surroundings it is not necessary to keep the tube 113 inside the housing 328 before use, and the injector device is provided with horizontal flanges 5 which can keep the coiled tube 113 in place when the injector device is placed inside the packing.
[0070] Before use and during storage the injector device 310 ′ is kept inside the packing, the needle/cannula side of the injector device 310 ′ is turned towards the first part of the packing and a second part of packing is secured to the rim 2 d of the first part of the packing in order to assure an airtight closure of the sterile packing. The injector device 310 ′ is placed in the circle part with the largest diameter and the center C 1 , the tube 113 is coiled around the injector device 310 ′ and fitted in between the flanges 5 , the connector (not shown) which is unreleasably fastened to the tube 113 and which can connect the tube to e.g. a pump and/or a reservoir for medication is placed in the circle part with the smallest diameter.
[0071] When the user wants to insert an infusion set 14 to the skin the following steps are performed:
I. The second part of the packing is removed.
Preferably the second part (not shown) of the packing has the form of a flexible membrane made by e.g. paper or plastic being glued or molded to the rim 2 d of the first part 1 of the packing.
II. The user take hold of the connector placed in the circle part with the smallest diameter, unwind the tube 113 which is coiled around the injector device 310 ′ and connects the tube 113 to a device that can provide fluid through the tube 113 e.g. to a pump combined with a reservoir. III. After unwinding the tube 113 it will be easy for the user to lift the injector device 310 ′ out of the first part 1 of the packing, bring the plunger to the retracted position, place the injector device 310 ′ against the skin and press the diametrically opposed depressions 303 thereby forcing the plunger to a forward position and inserting the infusion set 14 . The infusion set 14 is left inserted in the patient's skin while the injector device 310 ′ is removed. IV. After use the injector device 310 ′ is replace in the first part 1 of the packing in the circle part with the largest diameter, and from there the injector device 310 ′ is pushed into the circle part with the smallest diameter. Preferably the circle part with the smallest diameter is provided with means for retaining the injector device inside the first part 1 of the packing which will make it possible to dispose of the injector device after use without having to think about how to prevent surroundings from being exposed to the infected needle of the injector device 310 ′.
[0077] In order to make it possible to place the injector device 310 ′ inside the first part of the packing it is necessary that the outer dimension of the injector device, preferably the outer dimensions of the injector device 310 ′ with the tube 113 coiled around it, is smaller than the inner dimension of at least a part of the first part 1 of the packing, preferably the inner dimension of the circle part with the largest diameter.
[0078] In order to fasten the injector device 310 ′ inside the packing after use, at least a part of the packing is provided with a restricted room. In one embodiment this restricted room is partly constructed of the circle part with the smallest diameter and the center C 2 . The restriction can comprise a combination of a reduced cross-section e.g. as formed at the line B-B and one or more protrusions extending inward at the rim level. | This invention relates to a packing for an injector device for the placement of a subcutaneous infusion set on a patient. An insertion needle used in conjunction with an injector device is employed for transcutaneous placement of a soft and relatively flexible tubular cannula, followed by removal of the insertion needle and subsequent infusion of medical fluid according to the present invention can storage an injector device combined with an infusion set and an insertion needle under sterile conditions. The packing comprises at least—a first storage room storing the injector device combined with an infusion set and an insertion needle, —a first part ( 1 ) providing a further storage room ( 9 b ) isolated from the insertion needle ( 312, 26 ), is constructed with a bottom part ( 2 a , 2 b ) and walls ( 2 c ) standing upright form the bottom part ( 2 a , 2 b ), —a second part which is attached to the first part ( 1 ) before use in such a way that the conditions inside the packing remain sterile, and seen from a sectional view through the walls ( 2 c ), the walls ( 2 c ) are forming at least two sections each formed as a partial circle with at least two centres C 1 and C 2 and the centres C 1 and C 2 are placed with a distance D between them. | 37,156 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application claims priority to U.S. Provisional Application Ser. No. 61/043,933, filed Apr. 10, 2008, which is herein incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
This invention relates generally to articles formed from titanium alloys, and more specifically to articles having varying microstructures in pre-selected regions and methods therefore.
Titanium fan and compressor blade dovetails are susceptible to fretting and edge of contact (EOC) fatigue failures at the dovetail/disk slot contact location due to high contact stresses. Exemplary compressor blade dovetail fatigue failures are due to a) loss of wear coating on the dovetail surface, b) lever arm failures, c) vane bushing failures, and d) stick/slip condition with the mating titanium spool.
One approach used to address the problem of premature fatigue failure is replacement of a Ti6Al4V alloy with Ti4Al4Mo2Sn (Ti442) alloy. This high strength alloy considerably reduces dovetail failures. However, recurrence of dovetail failures pose a high cost to business and further reductions in fatigue failure are sought.
Generally, fan and compressor titanium-based blades comprise equiaxed alpha+beta titanium alloys. This microstructure provides a good balance of mechanical properties for the combined airfoil/dovetail structure. It is known in the titanium industry that titanium articles having bimodal (alpha+beta) or martensitic microstructures have superior high cycle fatigue (HCF) properties compared to mill annealed titanium articles. Articles having martensitic or bimodal microstructures are slightly harder and stronger than coarse or slow cooled microstructures. An increase in the hardness and yield strength of the titanium alloys increases the resistance to crack initiation by fatigue. Thus, any improvement in the strength of the titanium alloy increases fatigue resistance including resistance to environmentally- or contact-driven fatigue.
Martensitic and bimodal structures may be obtained through high temperature heat treat followed by water quench. However, the necessary heat treat/quench cycle cannot be applied to a substantially net-shaped airfoil due to dimensional distortion during heat treat and quench. Thus, the heat treat/quench process is not feasible on a complete blade.
Accordingly, it would be desirable to provide the dovetail region of a compressor blade that capitalizes on the high strength and fatigue resistance of bimodal and/or martensitic structure while preserving the airfoil dimension and mechanical properties.
BRIEF DESCRIPTION OF THE INVENTION
The above-mentioned need or needs may be met by exemplary embodiments which provide an article including a body comprising a titanium base alloy. The article includes at least a first portion and a second portion adjacent the first portion. The first portion comprises an alpha+beta microstructure and the second portion comprises a microstructure selected from a martensitic microstructure or a bimodal microstructure. In an exemplary embodiment, the microstructure of the second portion is achieved by selectively heating at least a surface region of the second portion followed by immediate quenching without substantially heating the first portion.
An exemplary embodiment is directed to a method that includes providing a near net-shaped article comprising a body comprising a titanium base alloy. The article includes a first portion and a second portion adjacent the first portion, wherein the near net-shaped article exhibits an alpha+beta microstructure substantially throughout the first and second portions. Thereafter, the second portion is processed to provide a pre-selected region of the second portion with a modified microstructure selected from a martensitic microstructure and/or a bimodal microstructure without substantially modifying the microstructure of the first portion.
An exemplary embodiment is directed to a method that includes providing a near net-shaped article comprising a body comprising a titanium alloy and having a first portion encompassing an airfoil region being shaped to substantially an airfoil final dimension and a second portion encompassing an unfinished dovetail region. The near net-shaped article exhibits an alpha+beta microstructure substantially throughout the first and second portions. Thereafter, at least a surface region of the second portion is selectively heated, followed by immediate quenching without substantially heating the first portion to provide a pre-selected region of the second portion with a modified microstructure selected from a martensitic microstructure and/or a bimodal microstructure without substantially modifying the microstructure of the first portion. Thereafter, the second portion is processed to a final body dimension.
BRIEF DESCRIPTION OF THE DRAWINGS
The subject matter which is regarded as the invention is particularly pointed out and distinctly claimed in the concluding part of the specification. The invention, however, may be best understood by reference to the following description taken in conjunction with the accompanying drawing figures in which:
FIG. 1 is a perspective view of a titanium alloy compressor blade.
FIG. 2 is a schematic representation of a compressor blade having an unmodified airfoil and a dovetail having a modified microstructure substantially throughout the dovetail thickness.
FIG. 3 is a schematic representation of a compressor blade having an unmodified airfoil and a dovetail having a modified microstructure in pre-selected regions.
FIG. 4 is a schematic representation of an unfinished dovetail having a modified microstructure and an exemplary induction heating assembly.
FIG. 5 is a micrograph of a portion of an unmodified airfoil exhibiting annealed alpha+beta microstructure.
FIG. 6 is a micrograph of a portion of a modified dovetail exhibiting a martensitic microstructure.
FIG. 7 is a micrograph of a portion of a modified dovetail exhibiting a bimodal (alpha+beta/martensitic) microstructure.
FIG. 8 is a flowchart illustrating an exemplary process.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings wherein identical reference numerals denote the same elements throughout the various views, FIG. 1 depicts a component article of a gas turbine engine such as a compressor blade 20 . The compressor blade 20 is formed of a titanium-base alloy as will be discussed in greater detail below. The compressor blade 20 includes an airfoil 22 that acts against the incoming flow of air into the gas turbine engine and axially compresses the air flow. The compressor blade 20 is mounted to a compressor disk/spool (not shown) by a dovetail 24 which extends downwardly from the airfoil 22 and engages a slot on the compressor disk. A platform 26 extends longitudinally outwardly from the area where the airfoil 22 is joined to the dovetail 24 . The airfoil 22 has a leading edge 30 , a trailing edge 32 , and a tip 34 remote from the platform 26 .
The airfoil 22 is relatively thin measured in a transverse direction (i.e., perpendicular to a chord to the convex side drawn parallel to the platform). The dovetail 24 is relatively thick measured perpendicular to its direction of elongation.
The compressor blade 20 is made of a titanium-base alloy, which is an alloy having more titanium than any other element. One particular titanium-base alloy is known as Ti-442, having a nominal composition, in weight percent, of about 4 percent aluminum, about 4 percent molybdenum, about 2 percent tin, about 0.5 percent silicon, balance titanium. Another titanium-base alloy is known as Ti-811, having a nominal composition, in weight percent, of about 8 percent aluminum, about 1 percent molybdenum, about 1 percent vanadium, balance titanium. Another exemplary titanium-base alloy is known as Ti 64, having a nominal composition, in weight percent, of about 6 percent aluminum, about 4 percent vanadium, balance titanium.
In an exemplary embodiment, a near net-shape article is forged from a selected titanium alloy. As used herein, “near net-shape article” means that at least a portion of the article (i.e., the airfoil) has been shaped to substantially its final dimensions, but at least another portion of the article (i.e., the dovetail) has not been finally shaped. In the embodiments disclosed herein, the term “unfinished dovetail” is used to signify the dovetail potion of a near-net shape compressor blade that must still undergo final shaping processes. The unfinished dovetail distorts during the heat treatment/water quenching hardening process. Subsequent to the final forge operation, but prior to final shaping, the near net-shape article undergoes one or more process steps to achieve a desired modified microstructure in the dovetail. FIG. 4 depicts a near net-shape compressor blade 40 including an airfoil 42 and unfinished dovetail 44 . Airfoil 42 has an alpha+beta microstructure that is maintained throughout subsequent processing.
After achieving the desired alpha+beta phase in the near-net shape article, including airfoil 42 , the unfinished dovetail 44 is subjected to one or more selected process steps to attain a modified microstructure in pre-selected regions or throughout the dovetail thickness. In an exemplary embodiment, the modified microstructure 45 includes a martensitic microstructure throughout the dovetail thickness, schematically represented in FIG. 2 . In another exemplary embodiment, the modified microstructure 45 includes a bimodal microstructure. The martensitic microstructure 46 may be present at the periphery of the dovetail, referred to herein as “skin depth,” schematically represented in FIG. 3 . Typically “skin depth” is about 5 to 10 mills in from the outer surface.
In an exemplary embodiment, the high strength unfinished dovetail 44 is achieved through a heat treatment immediately followed by a water quench. The heat treatment may be provided by induction heating, laser treatment, or electron beam methods. An exemplary apparatus is schematically represented in FIG. 4 . An exemplary apparatus includes a hollow ceramic vessel 48 adapted for insertion of the unfinished dovetail 44 . In this embodiment, induction heating coils 50 are utilized to provide the requisite heat treatment. Alternate heating methods may be utilized. For example, it is contemplated that laser beams may be utilized to heat pre-selected regions of the unfinished dovetail 44 . Alternately, electron beam radiation may be utilized. An important consideration is the rapidity with which the water quench can occur after heating. Those with skill in the art will appreciate that induction heating, laser treatment, or electron beam methods can provide a rapid, controlled heating environment. The temperature and duration of the heat treatment, followed by adequate water quench, impacts the resulting microstructure within the dovetail. For example, heat treatment below the beta solvus temperature, followed by immediate quenching, is a prerequisite for a bimodal microstructure. Heat treatment above the beta solvus temperature, followed by immediate quenching, results in martensitic microstructure. The depth of the modified microstructure (i.e., skin depth) may be dependent on the duration of the heat treatment. In general, only the unfinished dovetail 44 is subjected to the additional heat treatment, thus preserving the alpha+beta structure of the airfoil 42 shown in FIG. 5 . FIGS. 6 and 7 respectively show the martensitic microstructure and the bimodal structure achieved in the dovetail according to embodiments disclosed herein.
Following the heat treatment/quench process, the near net shape blade is finished to a final shape. FIG. 8 depicts an exemplary process for achieving the desired microstructure in the airfoil and dovetail. The near net-shaped article is provided following a final forging operation (Step 110 ). The article is subjected to one or more subsequent processes (Step 112 ). The subsequent processes may include heat treating, milling cleaning, inspecting etc., as necessary. During or after any of the individual processes provided in Step 112 , the unfinished dovetail is subjected to the controlled heat treatment/water quench process to achieve the desired microstructure (Step 114 ). After hardening of the unfinished dovetail, the article is finished to its final dimension (Step 116 ). Step 116 may include one or more of broaching, machining, shot peening, plasma coating or other processes known to those with skill in the art.
Exemplary embodiments disclosed here are particularly directed to compressor blades. However, the principles disclosed herein are applicable to other articles and processes where selected hardening is desired.
EXAMPLES
Example 1
Triple Phase Ti442 Fan and Compressor Blade. 1350° F./4-6 hr anneal for airfoil toughness; Heat treat dovetail region at 1600° F.-1750° F. for up to five minutes for fatigue resistance in air or argon atmosphere; Immediate water quench; Vacuum stress relieve at 1020° F. for 2 hrs. Dovetail heat treat accomplished by induction, laser, or electron beam. Hardening occurs throughout dovetail thickness or skin depth. Results: Blade is martensite—OR—bimodal structure at dovetail—AND—alpha+beta in the airfoil. In one embodiment, short induction heating, generally less than 15 seconds, results in skin depth martensitic structure. Induction heating for from 15 to 180 seconds results in a martensitic structure throughout the dovetail thickness. The strength of the dovetail is increased about 30% over comparable unmodified dovetail. For example, an observed Ti442 dovetail hardness increased to 47 Rc from its original 36 Rc (unmodified structure) In an exemplary embodiment, the strength of Ti442 dovetails having a modified microstructure is comparable to Inco 718 alloy. It is contemplated that the stress relieve process may be performed at temperatures from about 1000° F. to about 1200° F.
Example 2
Triple Phase Ti64 Fan and Compressor Blade. 1300° F./2 hr anneal for airfoil toughness; For fatigue resistance, heat treat dovetail region at 1700° F.-1850° F. for up to 5 minutes in air or argon atmosphere; Immediate water quench; Stress relieve at 1020° F. for 2 hrs. Heat treat accomplished by induction, laser or electron beam. Hardening throughout dovetail thickness or skin depth. Results: Blade is martensite—OR—bimodal structure at dovetail—AND—alpha+beta in the airfoil. An observed Ti64 dovetail hardness increased to greater than 40 Rc from its original (unmodified) hardness.
Example 3
Triple Phase Ti811 Fan and Compressor Blade. 1350° F./2 hr anneal for airfoil toughness/age; For fatigue resistance, heat treat dovetail at 1800° F.-1950° F. for up to 5 minutes in air or argon atmosphere; Immediate water quench; Stress relieve at 1020° F.-1350° F. for 2 hrs. Heat treat accomplished by induction, laser, or electron beam. Hardening throughout dovetail thickness or skin depth. Results: Blade is martensite—OR—bimodal structure at dovetail—AND—alpha+beta in the airfoil. A preferred stress relief is 2 hrs at 1020° F. after induction hardening. An observed Ti811 dovetail hardness increased to greater than 36 Rc from it original (unmodified) hardness.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to make and use the invention. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims. | Article (e.g., turbine engine fan or compressor blade) comprising a titanium alloy has a first portion with alpha+beta microstructure and a second portion with martensitic or a bimodal microstructure. The modified microstructure of the second portion is provided by selectively heating, and immediately quenching, the second portion without substantially heating the first portion. An exemplary method includes providing a near net-shaped article having a first portion (e.g., an airfoil region) and a second portion (e.g., an unfinished dovetail region). Initially, the article comprises an alpha+beta microstructure throughout. Thereafter, the second portion is selectively heated, followed by immediate quenching, without substantially heating the first portion, to modify the microstructure of the second portion to a martensitic or bimodal microstructure without substantially modifying the microstructure of the first portion. Thereafter, the second portion may be processed to a final body dimension. | 16,288 |
BACKGROUND OF THE INVENTION
This invention relates to projection video systems and specifically to a color correction systems for a projection video systems utilizing a single light valve, but multiple sources of illumination.
Most commercially available projection video systems utilize separate projection systems for each of the three primary colors. The systems thus require three light valves with separate optical systems which must be accurately converged on the screen, which adds to complexity and expense. Recently, projection video systems utilizing only a single light valve have been developed. One such system is a color field sequential system, in which the normal video field, 1/60th of a second, is broken into three parts, or color subfields of 1/180th of a second. During the three color subfields, the light valve is illuminated with red, green and blue light sequentially. While the light valve is illuminated with any given color, the video data corresponding to that color is displayed on the light valve. The eye then fuses the three color sub-fields into a single, full color field. The eye also fuses successive video fields and frames into full motion, full color video.
Recently, improved light valves particularly suitable for use in projection television systems have become available. One such device is a so-called deformable mirror device (sometimes called a digital mirror device or DMD) which is illustrated in U.S. Pat. No. 5,079,544 and patents referenced therein, in which the light valve consists of an array of tiny movable mirror-like pixels for deflecting a beam of light either to the display screen (on) or away from the display optics (off). This device is suitable for use in a field sequential system because its pixels are capable of being switched very rapidly. By further rapid switching of the pixels a grey scale is generated.
In addition to improved light valves for use in projection video systems, improved projection lamps are also now available. These projection lamps are highly efficient and have a long life. Furthermore, these lamps are physically quite small and have a small arc length. Small size and small arc length can significantly reduce the size and cost of the optics used to project the light onto the light valve as well as onto the viewing surface. Smaller optics can considerably reduce the overall cost of a video projection system since the optical elements of the system are a very significant portion of the overall cost. Many such lamps are also capable of following an electrical drive signal with good fidelity, i.e. they have a fast rise and fall time and can follow any reasonable waveform, including squarewaves. One such lamp is the Philips CSL-R100W Ultra High Pressure Projection lamp.
However, many otherwise suitable lamps may not have even color distribution across the visible spectrum, i.e. they may be deficient in one or more colors. Furthermore, these lamps have carefully designed thermal properties which require operation at a given power level in order to assure optimal power dissipation. Accordingly, such lamps require a consistent power input over time, such as 100 watts. If greater power is input to the lamp, the lamp will have a significantly shortened life span but turning down the power input to the lamp will cause the lamp to become unstable or go out altogether. The present invention is directed towards providing a three-lamp, single light valve projection video system that can take full advantage of these improved projection lamps while operating the lamps at optimum parameters.
In addition to correcting for any color spectrum deficiencies of the projection lamps used in a projection video system, a suitable video projection system must also provide for color correction of the dichroic filters utilized to convert the white light output from the projection lamps to the primary colors. Dichroic filters are manufactured in a batch process and there are sample to sample variations in the colorimetry of these filters. Additionally upon exposure to the intense light of projection lamps, the colors of the dichroic filters may fade. Accordingly, any suitable projection system must be able to compensate for batch to batch variation and/or fading of the dichroic filters. Finally, a suitable projection video system should also provide for color correction based on user preference, either statically or dynamically.
U.S. patent application Ser. No. 08/141,145 filed Oct. 21, 1993 entitled "Color Correction System for Video Projector", is directed to a method for dynamically color correcting a projection video system utilizing a single projection lamp, a color wheel of dichroic filters and a single light valve. The disclosure of U.S. application Ser. No. 08/141,145 is hereby incorporated by reference, as if fully set forth herein. The present application is directed to a color video projection system utilizing multiple projection lamps and a single light valve.
SUMMARY OF THE INVENTION
This invention is directed to a color correction system for a projection video system utilizing a single light valve with multiple projection lamps. The system is capable of varying the light output of the projection lamps without varying the electrical power input thereto so as to permit the lamps to be driven in accordance with their operating parameters. The system occludes unwanted optical output in synchronization with system requirements and is responsive to user input as well as dynamically electrically controllable.
The video projection system includes a light valve for modulating light impinging thereon with the video signal and three projection lamps, one for each of the primary colors, which are activated sequentially. Positioned in the light path between two of the lamps and the light valve are occluders which block and unblock the light output from their associated lamp. The lamps which have the occluders are operated such that each lamp may be driven with a series of non-occluded pulses and occluded pulses. The occluded pulses occur when the occluder blocks the light output from the lamp. The more a desired reduction in output in one of the colors is required, the non-occluded pulses are reduced and the corresponding occluded pulses are increased. This permits adjustment of the color temperature of the system to user preference without adversely affecting the electrical properties of the lamp. As such, the electrical power input to each of the lamps remains within operational parameters but the optical output of a particular color as seen by the light valve and thus the viewer is reduced.
BRIEF DESCRIPTION OF THE DRAWINGS
For better understanding of the invention, reference is made to the detailed specification to follow, which is to be taken in conjunction with the following drawing figures;
FIG. 1 is a schematic diagram of a projection video system using multiple projection lamps and a single light valve;
FIG. 2 illustrates a schematic diagram of a color projection video system utilizing three projection lamps and a single light valve and a means for dynamically adjusting the colorimetry of the system; and
FIG. 3 is a timing diagram of the driving and occluded pulses for the three projection lamps.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 illustrates schematically an illumination system for projection color video system utilizing three projection lamps to illuminate a single light valve. This illumination arrangement nearly triples the brightness of the projected image over a single lamp, single light valve system. FIG. 1 illustrates an illumination system 10 for illuminating a light valve 12 by three projection lamps 14, 16 and 18. The projection lamps 14, 16 and 18 are driven from a power source 20 by a sequential switch (commutator) 22 operated by control electronics 23. As is shown in FIG. 1, the white light emitted by each of the lamps is directed to dichroic mirrors 24, 26. Dichroic mirror 24 reflects green light and transmits blue light. Thus, the light from lamp 14 after passing through dichroic mirror 24 will have color components other than be blue subtracted and the light from lamp 16 after reflecting from dichroic mirror 24 will be green as its other components will not be reflected from mirror 24. Dichroic mirror 26 reflects red light and passes blue and green light. Thus, the red components of light emitted by lamp 18 will be reflected by dichroic mirror 26 to light valve 12.
The net result of the lamp and filter arrangement is that when lamp 14 is activated by switch 22, light valve 12 will be illuminated by blue light only, when lamp 16 is activated, DMD 12 will be illuminated by green light only and when lamp 18 is activated, light valve 12 will be illuminated by red light only. Integrator optics 28 may be disposed between dichroic mirror 26 and light valve 12 so as to provide a uniform field of illumination. Light valve 12 modulates the light under the control of light valve electronics 33 in accordance with the incoming video information 34. After modulation by light valve 12, the light passes to optics 30 and viewing screen 32. Light valve electronics 33 also provides a sync output signal 38 to the input of electronics 23 which controls switch 22. The color subfields generated will be integrated by the eye into a full color picture.
FIG. 2 illustrates a multiple lamp, single light valve projection video system 60 which permits varying the light output of the projection lamps, so as to provide for color control, without varying the electrical power input to the projection lamps so that the optimal operating conditions are maintained. System 60 includes a light valve 62 driven by light valve electronics 64 which in turn receives an input video signal 66. Light valve 62 modulates light impinging thereon in accordance with video signal 66 under the control of the light valve electronics 64. Light valve 62 is sequentially illuminated with red, green and blue light. While light valve 62 is illuminated with a given color (a color sub-field), the video data corresponding to that color is displayed on the light valve by light valve electronics 64. The eye fuses the three color subfields into a single full color field and successive video fields into a full motion, full color video. The modulated light from the light valve is projected by projection optics 68 to a viewing screen 70, which may be of the front or rear projection configuration.
A synchronization signal 72 is output from light valve electronics 64 to a lamp controller/driver 74. Lamp controller/driver 74 has separate drive (power) outputs 76, 78, 80 to three separate projection lamps 82, 84, 88. Disposed in the output path of projection lamps 82, 84, 88 are dichroic filters 90, 92. Dichroic filter 90 reflects red light and passes blue and green light. Thus, the red component of the white light output of lamp 82 will be reflected by dichroic mirror 90 to light valve 62. Dichroic filter 92 reflects blue light and passes green light. Thus, the green component of the white light output of projection lamp 84 will be passed through of dichroic filter 92 and will impinge on light valve 62 after passing through dichroic filter 90 which also passes green light. Dichroic filter 92 will also reflect the blue component of projection lamp 88 and illuminate light valve 62 with it after passing through dichroic filter 90. Thus, the net result of the arrangement of projection lamps 82, 84, 88 and dichroic filters 90, 92 is that projection lamp 82 functions as the "red" illumination lamp, projection lamp 84 functions as the "green" illumination lamp and projection lamp 88 functions as the "blue" projection lamp.
Also disposed in the illumination path of "green" projection lamp 84 is an occluder (shutter wheel) 94. A second occluder 96, is positioned in front of "blue" lamp 88. Occluders 94, 96 have been illustrated in their simplest form, that is of circular rotating wheels which are approximately 2/3 opaque with light transmissive segment 98 in wheel 94 and a light transmissive segment 100 in wheel 96. Occluders 94, 96 are driven by phase locked servo motors 102, 103 which are controlled by occluder driver 104 which receives a control input 105 from lamp controller/driver 74. Lamp controller/driver 74 includes user inputs 106 R , 106 G and 106 B so that the overall colorimetry of the projected image may be adjusted. Additionally, a color sensor 107 located at the output of light valve 62 may also input a signal 108 to lamp controller/driver 74 to permit automatic adjustment of color temperature.
The synchronization and drive arrangement for the three lamps 82, 84, 88 and the two occluders 94, 96 is shown in FIG. 3. If extremely precise color control or a greater range of adjustment is needed, a third occluder can be positioned in front of "red" lamp 82, however there is generally no need for occluders in front of all of the lamps because the relative color balance of the system can be adjusted by changing the light output of two of the three primary colors. As a practical matter, the un-occluded lamp will be that of the color which the lamp is least spectrally efficient. For the purposes of this discussion, we will assume that this is "red" lamp 82.
FIG. 3 illustrates the electrical power output to the "red", "green" and "blue" lamps through lines 76, 78 and 80. As is indicated on the bottom (red) graph of FIG. 3, the small tick marks indicate the color subfields with the video field comprising three color subfields. The lowermost graph of FIG. 3 illustrates the power output through line 76 to lamp 82 which forms the red illumination. As is seen a positive going pulse 110 is applied to lamp 82 for one color subfield (in this case red). No power is applied to lamp 82 for the next two color subfields (i.e. the green and the blue subfields). Thereafter, a negative going pulse 110' is applied to lamp 82 through line 76. The result of this operation is that lamp 82 is energized for one-third of the video field with an amplitude A R with pulses both positive 110 and negative 110 going so that the lamp is driven under optimal conditions. In FIG. 3 the electrical power input to the lamps is the amplitude of the pulses times the duration of the pulses. As is seen in FIG. 3, the amplitude A R of "red" pulses 110 is greater than that of the other colors as will be described in detail below.
The middle timing chart of FIG. 3 illustrates the power input to lamp 88 which is the "blue" lamp by the action of dichroic filter 92. Also disposed in the illumination path of lamp 88 is occluder 96. As is seen, lamp 88 is powered by a series of positive pulses 112 and negative pulses 112' for one-third of the video field (i.e. during the "blue" color subfield). Pulses 112, 112' occur when the light transmissive segment 100 of occluder 96 is positioned in front of lamp 88. However, the blue power pulses 112, 112' have an amplitude A B (illustrated by the height of pulses 112, 112' in graph 4) which is less than that of red pulses 110, 110'. Thus, the total power of non-occluded pulses 112 and 112' is less than the full power requirement of lamp 88. However, as noted above, many sophisticated projection lamps cannot be operated at less than full power, averaged over a period of time, without operational difficulties which can lead to premature lamp failure.
In order to restore proper electrical power input to lamp 88, it is activated with a series of compensatory pulses 114, 114' which are again both positive and negative going. However, the pulses 114, 114' occur when the opaque portion of occluder wheel 96 is positioned so as to block the light output from lamp 88. Thus, there is no light output to light valve 62 by lamp 88 during pulses 114, 114'. The duration and amplitude of the pulses 114 and 114' are adjusted so as to restore the total electrical power input to lamp 88 to the desired amount so that its operational characteristics will not be affected. The amplitude A B of non-occluded pulses 112', 112 is less than that of "red" pulses 110, 110'. However, the total electrical power input to lamp 88 is the sum of non-occluded pulses 112, 112', and occluded pulses 114, 114'. The result of this operation is that the optical output of lamp 88 to light valve 62 is reduced but its electrical input remains at the optimal level so that its operational characteristics are not affected.
Similarly, "green" lamp 84 is driven with a series of non-occluded pulses 116, 116' and a series of occluded pulses 118, 118'. It is seen that the amplitude A G of non-occluded pulses 116 are the lowest which means that the non-occluded electrical input to the "green" lamp 84 is the lowest, which would be the case where the lamp is spectrally efficient in green. Accordingly, the compensatory occluded pulses 118, 118' are the largest so that the total power input to lamp 84 remains at the optimum level. In summary, as the drive arrangement in FIG. 3 illustrates, all of the lamps see exactly the same input electrical power so that their operating characteristics are optimum.
In operation, if the user deems the picture on screen 70 to be "too green", the user would operate control 106 G which causes lamp controller 74 to alter the relationship of the driving pulses on line 78 to lamp 84. If a reduction in green is desired, non-occluded pulses 116, 116' are reduced in amplitude. However, in order to maintain proper electrical power input to lamp 84, occluded pulses 118, 118' are increased in amplitude so that the total electrical power to lamp 84 remains the same. Since, however, the non-occluded pulses have been reduced in amplitude, the total light output of lamp 84 is reduced and thus the overabundance of green is compensated for. A similar operation will occur with respect to blue lamp 88. If the picture projected on screen 70 is too blue, non-occluded pulses 112, 112' to lamp 88 are reduced and occluded pulses 114, 114' would be increased by operation of control 106 B .
The question arises as to how to compensate for a picture that is "too red" since "red" lamp 82 has no occluding device positioned in front of it and, as noted above, its power input cannot be turned down without possible malfunction. The answer is that both blue and green power is reduced by controls 106 G , 106 B so that the relative amount of red increases. The automatic control of color sensor 107 would also cause lamp controller/driver 74 to operate in a similar manner to adjust the color balance to a preset point.
Occluder driver 104 drives motors 102, 103 so that the light transmissive portions of occluders 94, 96 are positioned in front of their respective lamps 84, 88 during the time that the non-occluded pulses occur. Occluder driver 104 receives a control input from lamp controller/driver 74 which in turn is synchronized to light valve 62 by light valve electronics 64 so that occluders 94, 96 are synchronized to the incoming video and illumination signals. As a practical matter the requirement that the light valve be loaded with video data constrains the start and stop points of the non-occluded pulses to defined non-arbitrary locations. However the occluded pulses 114, 114', 118 and 118' may occur at any time during the other two-thirds of the video field, the timing between occluders 94, 96 and the occluded pulses is thus not particularly critical. It is merely necessary that the occluded pulses occur during the period when the output of the respective lamps are occluded. Further, the waveform of the occluded pulses is not critical and may be of any form sufficient to drive the lamps under optimum operating conditions. The waveforms of the occluded pulses may also be utilized to facilitate re-ignition of the lamps by the non-occluded pulses.
The devices used to occlude the light output from the projection lamps need not be motor driven shutter wheels as illustrated in FIG. 2. The occluders may be any form of controllable shutter suitable for occluding the output of projection lamps. Such suitable occluders can be mechanical shutters operated electrically or shutters in the form of electrically operated dispersive liquid crystal devices. The only requirement is that the shutter be capable of a synchronized operation with the illumination of the lamps. Mechanical variable density occluders could also be used to provide the function of the occluder wheels, however this would preclude dynamic color adjustment.
Lamp controller/driver 74 may be implemented in a number of ways. Similar to the lamp driver in application Ser. No. 141,145 referred to previously; controller driver 74 may consist of a voltage output square wave generator coupled to a current amplifier whose three outputs follow the voltage inputs. Many commercially available power supplies may also be used,the only requirement is that the controller driver be capable of proportioning the power output between the non-occluded and occluded pulses so that the total power supplied to each lamp remains constant. The three separate color controls 106 R , 106 B , and 106 G may also be replaced with a single "tint" control.
The above-described embodiments are merely illustrative of the principles of the present invention. Numerous modifications and variations thereof will be readily apparent to those skilled in the art without departing from the spirit and scope of the present invention. | A color correction system for a video projection system utilizing a single light valve for modulating light impinging thereon with a video signal and three projection lamps, one for each of the primary colors, which are activated sequentially. Positioned in the light path between two of the lamps and the light valve are occluders which block and unblock the light output from their associated lamp. The lamps which have the occluders are operated such that each lamp may be driven with a series of non-occluded pulses and occluded pulses. The occluded pulses occur when the occluder blocks the light output from the lamp. The more a desired reduction in light output in one of the colors is required, the non-occluded pulses are reduced and the corresponding occluded pulses are increased. This permits adjustment of the colorimetry of the system without adversely affecting the electrical properties of the lamp. As such, the electrical power input to each of the lamps remains within operational parameters but the light output of a particular color as seen by the light valve, and thus the viewer, may be reduced. | 21,979 |
CLAIM FOR PRIORITY
This application is a continuation of application Ser. No. 10/231,025, filed on Aug. 30, 2002, now U.S. Pat. No. 7,668,946 and claims the benefit of U.S. Provisional Application No. 60/316,022, filed on Aug. 31, 2001, all of which are incorporated herein by reference.
BACKGROUND
1. Technical Field
The present invention generally relates to predicting traffic volume on the Internet, and more specifically to predicting traffic volume to assist in marketing, planning, execution, and evaluation of advertising campaigns for the Internet.
2. Related Art
The number of users on the Internet continues to grow at an astounding rate while businesses continue to rapidly commercialize its use. As they surf through websites, users generate a high volume of traffic over the Internet. Increasingly, businesses take advantage of this traffic by advertising their products or services on the Internet. These advertisements may appear in the form of leased advertising space on websites, which are similar to rented billboard space in highways and cities or commercials broadcasted during television/radio programs. Experience has shown that it can be difficult to plan, execute, and/or evaluate an advertising campaign conducted over the Internet. Unlike billboards and commercials, there are very few tools (e.g., Nielson ratings, etc.) to accurately measure or predict user traffic on the Internet.
One method for measuring exposure of advertisements posted on a website may be based on daily traffic estimates. This method allows one to control the exposure of an ad and predict the traffic volume (i.e., number of impressions, viewers, actions, website hits, mouse clicks, etc.) on a given site at daily intervals. However, there is no control over how this exposure occurs within the day itself because the method assumes a constant rate of traffic throughout the day. Experience has shown that website traffic typically exhibits strong hourly patterns. Traffic may accelerate at peak-hours, and hence, so does ad exposure. Conversely, at low traffic times, ads may be viewed at a lower rate. These daily (as opposed to hourly) estimates exhibit high intra-day errors, which result in irregular or uneven ad campaigns that are not always favored by advertisers.
This situation is illustrated in FIG. 1 , where a pattern of under-over-under estimation is evident. Traffic volume in the hours of 12:00 am to 5:00 am, 6:00 am to 2:00 pm, and 3:00 pm to 11:00 pm are overestimated, underestimated, and overestimated, respectively. FIG. 2 shows error size for each hour relative to the traffic volume for the entire day. Note that errors tend to average out during the day. However, during times of high relative error, ad campaigns based on a daily traffic estimate tend to accelerate; while at times of low (negative) relative error, these same ad campaigns tend to dramatically decelerate. This situation yields an uneven campaign with “run-away” periods followed by “stalled” periods of exposure.
Campaign unevenness is a symptom of prediction errors (positive or negative). As illustrated in FIG. 2 , taking the values of these hourly errors relative to a day's total traffic can give a good indication of the gravity of the campaign's failure to predict intra-day traffic patterns. By summing the absolute value of these relative hourly errors, it is clear that the prediction errors can amount to close to half (48.32%) of the day's total traffic, even though the prediction for the overall daily traffic is accurate. A single hour's prediction error as a percentage of that hour's actual traffic can be much more dramatic. For instance, the hour starting at 9:00 am has a predicted traffic volume of 156,604, but the actual traffic volume is only 15,583, which is an error of 905% for that hour. Similarly for the hours of 1:00 am to 4:00 am, underestimation (per hour) ranges between 40 and 50 percent relative to the actual traffic volume for each respective hour.
Because of the dynamic nature of the Internet, it is difficult to predict the amount of time it will take before advertising goals for a particular advertisement are met. Therefore, it would be beneficial to provide a mechanism to better estimate traffic volume.
SUMMARY OF EXEMPLARY EMBODIMENTS
Methods, systems, and articles of manufacture of the present invention may assist in planning, execution, and evaluation of advertising campaigns on the Internet. Particularly, methods, systems, and articles of manufacture of the present invention may help evaluate and/or predict traffic volume on the Internet.
One exemplary embodiment of the invention relates to a method for predicting traffic. The method may comprise receiving historical traffic data for a location, and computing a prediction of traffic volume for a particular time at the location using the historical traffic data and at least one prediction algorithm.
Additional embodiments and aspects of the invention are set forth in the detailed description which follows, and in part are obvious from the description, or may be learned by practice of methods, systems, and articles of manufacture consistent with the present invention. It is understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several embodiments of the invention and together with the description, serve to explain the principles of the invention. In the drawings:
FIG. 1 illustrates an exemplary pattern of under-over-under estimation consistent with the prior art;
FIG. 2 illustrates exemplary errors in the pattern relative to a day's total traffic consistent with the prior art;
FIGS. 3A and 3B illustrate exemplary linear relationships in hourly traffic consistent with features and principles of the present invention;
FIGS. 4A and 4B compare the performance between various exemplary prediction methods consistent with features and principles of the present invention;
FIG. 5 illustrates an exemplary predictability map consistent with features and principles of the present invention;
FIG. 6 illustrates an exemplary system for predicting traffic consistent with features and principles of the present invention;
FIG. 7 illustrates an exemplary method for predicting traffic consistent with features and principles of the present invention; and
FIG. 8 illustrates an exemplary method for conducting an ad campaign consistent with features and principles of the present invention.
DETAILED DESCRIPTION
Reference is now made in detail to exemplary embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used throughout the drawings to refer to the same or like parts.
As discussed above, one method for predicting traffic may estimate a daily traffic volume for a location and use the estimate to compute a constant traffic rate throughout the day. However, other methods (e.g., hour-of-day means method, previous-hour method, previous-hour-plus-drift method, point-slope method, etc.) described below, may also be used to compute traffic predictions using different time intervals, such as with hourly predictions.
One exemplary method for predicting traffic may compute traffic averages for each hour of a day. The hour-of-day means (HDM) method may assume that traffic depends only on the hour of the day regardless of an overall traffic trend at other times of the day. For example, let x i,k j represent the measured traffic volume of location j during hour k of day i. Assuming
x i,k j =v k j
where v k j is a random variable with mean μ k j and variance (σ k j ) 2 that describes the traffic volume at location j according to the k th hour (k=0, . . . , 23), the family of x i,k j for i=1, 2, . . . is then a sequence of independent, identically distributed (i.i.d.) random variables. For illustrative purposes, the following example focuses on a single location. Hence, the superscript j may be dropped from the notation.
Letting E i,k [.] denote an expectation operator conditioned on hour k of day i (i.e., the history of the traffic volume for the location is known up to hour k of day i), the HDM method may then use the expectation as a forecast of the traffic volume for the next hour, which yields
E i,k [x i,k+1 ]=E[v k+1 ]=μ k+1
As one of ordinary skill in the art of traffic estimation can appreciate, for all l less than i, the HDM method may have
E l,k [x i,k ]=μ k
A traffic volume predictor v k for μ k may be constructed using the above results. From a history containing n days of measured traffic volume data, v k may be computed as
V _ k = 1 n ∑ i = 1 n x i , k
for each k=0, . . . , 23. Therefore, in the HDM method, the traffic volume prediction {circumflex over (x)} k at an hour k for any day is given by
{circumflex over (x)} k = v k
which is simply the mean of the measured traffic volume at hour k over a history of n days. The history of n days may be n consecutive or nonconsecutive days.
The variance of the predictor v k is given by
var [ v _ k ] = σ ^ k 2 n
where {circumflex over (σ)} k 2 is the estimated variance of the measured traffic volume at hour k over n days and is given by
σ ^ k 2 = 1 n - 1 ( ∑ i = 1 n ( x i , k 2 ) - n v _ k )
Hence, the rate of reduction of the variance of {circumflex over (v)} k (in percentage terms) as the history increases from n to n+1 is n/(1+n 2 ), or approximately 1/(1+n) as n becomes large. This result shows that gaining accuracy in traffic volume prediction may become increasingly difficult after the history grows beyond a certain number of days. Even assuming that hourly means of traffic volume are stationary (i.e., they don't change over time), accuracy in their estimation is limited by available computational resources. Because of the slowdown in the prediction's convergence and the estimated magnitude of the variance for typically measured traffic at a location, a three-month history provided to the predictor v k would give predictions exhibiting up to 20% volatility. Table 1 shows some exemplary results for high traffic locations.
TABLE 1
Volatility comparison
History Size
Volatility of Prediction
(days)
(%)
30
~20
60
~13
90
~10
120
~10
Another exemplary method for predicting traffic may assume that traffic at a location obeys a random walk with zero mean scenario. That is, traffic at a given hour may be predicted by traffic at a previous hour plus a zero-mean, random disturbance. The previous-hour (PrevHr) method can capture the effect of “traffic momentum” (i.e., the momentum of traffic from the previous hour carries over to the next hour). For example, the PrevHr method may assume the following structure
x i,k+1 j =x i,k j +ε k j
where ε k j is a random variable with E[ε k j ]=0 and var(ε k j )=σ ε k j 2 .
Limiting the analysis to a single location, superscript j may be dropped from the notation. Using expectation E i,k [.] as a forecast of the traffic volume for x i,k+1 and a history of measured traffic volume up to day i and hour k, the following equation is obtained:
E i,k [x i,k+1 ]=E i,k [x i,k +ε k ]=x i,k
Therefore, the predicted traffic volume {circumflex over (x)} i,k+1 at day i and hour k+1 is given by,
{circumflex over (x)} i,k+1 =x i,k
which is the measured traffic volume at day i and hour k. Note that for any hour m occurring after hour k, this method may predict the traffic volume at hour m to be the last measured traffic volume in the history.
Another exemplary method for predicting traffic may combine recent traffic information (e.g., traffic information from the previous hour) and a history of changes (i.e., drift) in traffic. The previous-hour-plus-drift (PrevHr+) method assumes the changes are of an additive, incremental form and the increments are adjusted according to the hour of the day, which allows the method to accommodate daily patterns observed in historical traffic data. For example, the PrevHr+ method may assume the following structure:
x i,k+1 j =Δ k+1 +x i,k j
where Δ k is a random variable describing the traffic increment for an hour k of the day. In this equation, the following convention is used: x i,0 j =Δ 0 +x i-1,23 j .
Again, dropping the superscript j and using the expectation as a forecast for the expected traffic volume, the following equation is obtained:
E i,k [x i,k+1 ]=E i,k [Δ k+1 ]+x i,k
As one of ordinary skill in the art can appreciate, traffic for m hours into the future may be forecasted in a recursive manner. That is, the above equation may be recursively applied to yield
E i , k [ x i , k + m ] = ∑ s = 1 m ( E i , k [ Δ k + s ] ) + x i , k
using the following conventions: x i-1,24 =x i,0 and E i,k [Δ k+s ]=E i,k └Δ mod(k+s,24) ┘. With a traffic history of n days, a traffic increment estimator may estimate the expectation E i,k [Δ k ] using
Δ ^ k = 1 n - 1 ∑ i = 1 n ( x i , k - x i , k - 1 )
Therefore, the forecast for the expected traffic volume may be rewritten as
E i,k [x i,k+1 ]={circumflex over (Δ)} k+1 +x i,k
and the predicted traffic volume {circumflex over (x)} i,k+1 at day i and hour k+1 is then given by
{circumflex over (x)} i,k+1 ={circumflex over (Δ)} k+1 +x i,k
which is the estimated traffic increment at hour k+1 plus the measured traffic volume in the previous hour.
The increment estimator {circumflex over (Δ)} k may only use the most recent three months of historical traffic data to generate the estimate because using more data may not significantly reduce the variance of the estimate. Using more data may also increasingly expose the estimate to incorrect modeling due to long-term, structural changes in traffic patterns. An increment variance estimator may approximate the variance of Δ k using
σ
^
Δ
k
2
=
1
n
-
1
∑
i
=
1
n
(
x
i
,
k
-
x
i
,
k
-
1
-
Δ
^
k
)
2
The variance estimator may be useful when the historical traffic data contains extreme traffic volume values or outlying data, as defined below. It is not unusual to encounter extreme values coming from errors or by omission in historical traffic data. For instance, a chain of missing values in the historical traffic data at times where traffic is typically high for a certain location may indicate that there has been some historical data capture problem. Of course, it may also mean that the location became unpopular and that traffic for those times was indeed zero. This type of atypical data is referred to as outlying data. The criteria for deciding between what is legitimate data and what is outlying data is rather subjective. However, traffic volume prediction may be improved if these extreme values are removed or corrected.
In one exemplary embodiment of the present invention, a filter may be used to correct or remove outlying data from the historical data. The filter may employ a criteria that assumes a measured traffic volume at some time (e.g., at day i and at hour k) in the historical data is outlying data when the measured traffic volume at that time lies more than N d standard deviations from the mean of the measured traffic volume at hour k over a history of n days. For example, the filter may estimate {circumflex over (Δ)} k and {circumflex over (σ)} Δ k 2 in the manner described above. If a measured traffic volume x i,k meets the following parameters:
x i,k >x i,k−1 +{circumflex over (Δ)} k +N d {circumflex over (σ)} Δ k
or
x i,k >x i,k−1 +{circumflex over (Δ)} k −N d {circumflex over (σ)} Δ k
then the measured traffic volume x i,k may be classified as outlying data and the filter may substitute x i,k−1 +{circumflex over (Δ)} k for x i,k in the historical traffic data. The predicted traffic volume may then be calculated using the corrected data as previously described.
Another exemplary method for predicting traffic may add another degree of freedom to the PrevHr+ method because the explanatory impact of recent traffic may vary according to the time of day in addition to a time-of-day dependent, additive shock. This method may assume a linear relationship between x i,k j and x i,k+1 j , and hence, is called the point-slope method. FIG. 3A shows an example of the linear relationship. It plots the measured traffic volume at the third hour versus the fourth hour of each day in February, 2001 at a test location. The plot shows the measured traffic volumes of the third and fourth hour form a linear pattern. This pattern may be found at most locations, but the strength and form of the linear relationship varies by hour and across locations. For example, FIG. 3B shows a similar relationship five hours later at the same location for the eighth and ninth hours, but while the relationship is still fairly linear, it significantly differs in slope (the solid line represents a 45-degree line in both FIGS. 3A and 3B ). In general, for most locations, the relationship between traffic at subsequent hours is linear enough to justify using the point-slope method as a first-order approximation.
From the above observations, the point-slope method may assume the following structure:
x i,k+1 j =a k+1 j +b k+1 j x i,k j +ε k+1 j
where a k j is a mean hour-of-day additive increment, b k j is a constant or a loading for the hour prior to hour k, and ε k j is a random variable (i.e., noise term) with zero mean (i.e., E i,k [ε k+1 ]=0) at location j and hour k. Focusing on one location (i.e., dropping superscript j), using the expectation as a forecast for the expected traffic volume, and recognizing that E i,k [x i,k ]=x i,k , the following equation is obtained:
E i,k [x i,k+1 ]=a k+1 +b k+1 E i,k [x i,k]+E i,k [ε k+1] =a k+1 +b k+1 x i,k
Traffic for more distant times in the future may be forecasted in a recursive manner. More specifically, a forecast for traffic volume m hours after the hour k may be given by
E
i
,
k
[
X
i
,
k
+
m
]
=
∑
h
=
1
m
(
a
k
+
h
∏
s
=
h
+
1
m
b
k
+
s
)
+
∏
h
=
1
m
b
k
+
h
x
i
,
k
As one of ordinary skill in the art can appreciate, the point-slope method, discussed above, uses a linear regression with x i,k as regress and and x i,k−1 as regressor. The coefficients a k and b k may not be directly observable from the historical traffic data, but they may be estimated using, for example, a least squares method. The least squares method may estimate a k and b k by minimizing a sum of squared errors
∑ i = 1 n ⅇ i , k 2 = ∑ i = 1 n ( x i , k - a ^ k - b ^ k x i , k - 1 ) 2
where e i,k is a prediction error between a predicted traffic volume at hour k of day i and the measured traffic volume at hour k of day i. Using first-order conditions to minimize
∑ i = 1 n ⅇ i , k 2 ,
the point-slope method may solve for coefficients â k and {circumflex over (b)} k to yield
b ^ k = ∑ i = 1 n ( x i , k x i , k - 1 ) - n x _ k x _ k - 1 ∑ i = 1 n ( x i , k - 1 ) 2 - n x _ k - 1 2 a ^ k = x _ k + b ^ k x _ k - 1
where
x _ k = 1 n ∑ i = 1 n x i , k and x _ k - 1 = 1 n ∑ i = 1 n x i , k - 1
with the convention x i,−1 =x i-1,23 . We may substitute the coefficient estimates for the coefficients a k and b k in the expected traffic volume forecast, and the predicted traffic volume {circumflex over (x)} i,k+1 at day i and hour k+1 is then given by
{circumflex over (x)} i,k+1 =â k+1 {circumflex over (b)} k+1 x i,k
In one exemplary embodiment, the hourly traffic predictions from any of the HDM, PrevHr, PrevHr+, and point-slope methods may be combined to predict the traffic volume for a location (e.g., a website) over a period of time comprising m z hours.
Using the point-slope method as an example, let {circumflex over (x)} i,k+1,z represent the predicted traffic volume for hour k+1 of day i in time niche z. Then, {circumflex over (x)} i,k+1,z may be calculated using
{circumflex over (x)} i,k+1,z =â k+1 +{circumflex over (b)} k+1 x i,k
From the previous results for E i,k [x i,k+m ], the traffic volume m hours after hour k of day i at a location may be calculated using
x ^ i , k + m = ∑ h = 1 m ( a ^ k + h ∏ s = h + 1 m b ^ k + s ) + ∏ h = 1 m b ^ k + h x i , k
If H z is a set of hours k+m, then the predicted traffic volume for a location during the H z hours may be calculated by
d ^ = ∑ k + m ∈ H z x ^ i , k + m
which is simply the sum of the individual hourly traffic volume predictions for the time defined by H z .
In general, the point-slope method may provide consistently accurate traffic volume predictions, but when the measured traffic volume contains structural traffic changes (e.g., outlying data), the method may “blow up” (i.e., yield extraordinarily large predictions). The traffic volume predictions may be filtered to prevent the blow ups using mathematical functions, distributions, or other criteria. For example, one embodiment of the present invention may construct a test statistic filter f({circumflex over (x)} i,k ), such that
f ( x ^ i , k ) = { 1 ; if x _ k - t c σ ^ k ≤ x ^ i , k ≤ x _ k + t c σ ^ k 0 ; otherwise
where t c is a threshold estimate, x k is the estimated mean of the measured traffic volume at hour k over n days, and {circumflex over (σ)} k is the estimated standard deviation of the measured traffic volume at hour k over n days. Table 2 shows the exemplary critical values of t c corresponding to the number of days n that may be used to compute the predicted traffic volume {circumflex over (x)} i,k . The t c values in Table 2 are based on a student-t distribution cumulative density function (c.d.f.) with a 99% cumulative probability criterion, but as one of ordinary skill in the art can appreciate, the values of t c may be based on any other statistical/mathematical function (e.g., discrete function, continuous function, Poisson c.d.f., binomial c.d.f., etc.) with any other criterion.
TABLE 2
Critical values of t c
n
t c
<20
2.878
21
2.861
22
2.845
23
2.831
24
2.819
25
2.807
26
2.797
27
2.787
28
2.779
29
2.771
30
2.763
31
2.756
32
2.750
33 to 42
2.704
43 to 62
2.660
63 to 122
2.617
>122
2.576
One exemplary embodiment of the present invention may use filter f({circumflex over (x)} i,k ) to measure whether {circumflex over (x)} i,k is believable based on historical traffic data. A problem with this is that if a permanent regime or behavioral change occurs in a traffic pattern, then past traffic data may become irrelevant. In spite of this, filter f({circumflex over (x)} i,k ) may be used to indicate whether a location's traffic pattern is stable enough for the point-slope method to be effective. If this is not the case, then when f({circumflex over (x)} i,k ) is zero, one embodiment may revert to other methods (e.g., HDM method, PrevHr method, etc.) that may not blow up in the face of pattern changes.
Table 3 uses various exemplary predictability scores to compare the performance of the HDM, PrevHr, PrevHr+, and point-slope methods in predicting traffic volume at a test location for a period from Feb. 1, 2001 to Feb. 28, 2001.
TABLE 3 Location A from Feb. 1, 2001 to Feb. 28, 2001 Total traffic = 92,407,331 impressions (total traffic volume) Daily Point- Mean HDM PrevHr PrevHr+ Slope Mean Error 3,396 (7,705) 123 103 (347) Standard Dev. 89,496 33,252 35,301 18,323 16,262 Maximum Error 239,809 175,126 186,993 146,510 144,192 Minimum Error 26 1 21 14 4 Normalized L1 47% 15% 17% 7% 6% Score
The predictions were computed using a 90-day sliding window of historical traffic data (i.e., when calculating the prediction for each hour of the day, only the most recent 90 days of traffic data were used). The comparison is made in terms of hourly prediction errors, where each method observed (i.e., recorded in the historical traffic data) the traffic volume for the last 90 days up to hour k of day i and computed a prediction {circumflex over (x)} i,k+1 for the next hour's traffic based on the observation. Each method continued predicting the traffic volume for the subsequent hour as the previous hour of traffic volume was observed. Then, from the prediction and the measured traffic volumes, the prediction errors e i,k were computed, as defined by
e i,k =x i,k −{circumflex over (x)} i,k
The predictability scores in Table 3 were calculated using
e _ = 1 24 n ∑ i = 1 n ∑ k = 0 23 e i , k
(mean error),
σ e = 1 24 n - 1 ∑ i = 1 n ∑ k = 0 23 ( ⅇ i , k 2 - 24 n e _ 2 )
(standard deviation),
e max = max { i , k } e i , k
(maximum error),
e min = min { i , k } e i , k
(minimum error), and
L 1 = ∑ i = 1 n ∑ k = 0 23 e i , k ∑ i = 1 n ∑ k = 0 23 x i , k × 100 %
(normalized L1 score)
Although the above lists the mean error, standard deviation, maximum error, minimum error, and normalized L1 score as possible predictability scores, other metrics (e.g., total traffic, etc.) may be used as a predictability score.
From Table 3, we can see that the PrevHr+ and the point-slope methods are among the best performers. The point-slope method in particular exhibits the lowest standard deviation and maximum error. The prediction method selected may depend on a user's objectives and willingness to trade-off error mean and variance. Table 3 also shows that the point-slope model has the lowest normalized L1 score. This may come at the expense of a higher mean error. However, this mean error may be orders of magnitude below what a method using daily means (instead of hourly predictions) would yield.
Predictability scores may provide a good criterion for selecting a method of predicting traffic based on a desired smoothness in deployment of an ad campaign. A smoothly deployed ad campaign exposes users to advertisements at a predictable pace. Hence, a smooth ad campaign may use a method that accurately predicts traffic volume. In contrast, an unsmoothly deployed ad campaign exposes users to advertisements unpredictably or even haphazardly until the exposure reaches a predetermined level that signifies the end of the campaign.
FIGS. 4A and 4B provide a visual perspective of the relative effectiveness of the different methods. The figures show the hourly traffic predictions of each method and the actual traffic for the test location on Feb. 18, 2001. The methods with better predictability scores seem to deliver more accurate predictions because their predictions match the later observed traffic volume more closely than the methods with worse predictability scores. In these figures, it is also easy to see some of the characteristics and possible limitations of each method.
A predictability score gives a measure of the size of a method's prediction error for an analyzed time period. That is, it may give a measure of a location's traffic predictability and may be used to compare the predictability of different locations. This is an important criterion when seeking smooth campaigns because it provides a comparison metric across different locations. The predictability score may be used for campaign decision-making. Campaigns with a high smoothness priority may deliver ads at locations based on the knowledge that the locations with a better predictability score may be more predictable and are likely to deliver smoother campaigns. Note that a first location's predictability score may be better than a second location's predictability score if the first score is lower or higher than the second score.
For example, consider the normalized L1 score in Table 4 for a second location B during the month of February. Compared with the performance results in Table 3, the location for Table 4 may be deemed less predictable because its normalized L1 score using the point-slope model is 12%, which is lower than the score (6%) for Table 3's location. However, the second location has less total traffic (i.e., 8,962,345 impressions) than the first location (i.e., 92,407,331 impressions). In general, lower traffic locations may be less predictable, so a predictability score based on total traffic would be better if it is higher.
TABLE 4
Location B from Feb. 1, 2001 to Feb. 28, 2001 Total
traffic = 8,962,345 impressions (total traffic volume)
Daily
Point-
Mean
HDM
PrevHr
PrevHr+
Slope
Mean Error
(1,003)
3,203
(26)
(27)
344
Standard Dev.
5,851
4,049
2,862
2,396
2,263
Maximum Error
15,482
15,309
11,292
8,907
8,578
Minimum Error
1
8
4
4
6
Normalized L1
32%
27%
15%
12%
12%
Score
It may be better to direct smoothness-sensitive campaigns towards locations with a better predictability score. Generalizing this idea, we can form a predictability map that compares how safe (in terms of smoothness) a location is relative to other locations. FIG. 5 illustrates an exemplary predictability map consistent with features and principles of the present invention. The map plots a predictability score, such as the L1 score, against the average daily traffic volume for three test locations. Although the predictability map in FIG. 5 is a scatter plot, one of ordinary skill in the art can appreciate that the predictability map may take the form of a contour plot, bar graph, line graph, or any other type of graph. From the map, location C appears to be a better target for a smoothness-sensitive campaign than location B because of its lower L1 score. However, we may target a group of locations for an ad campaign. The predictability score PRG of the group of locations may then be calculated using
PR G = ∑ j ∈ G T j PR j ∑ j ∈ G T j
where G is a set of all locations j in the group, T j is location j's total traffic per unit of time (i.e., day), and PR j is the predictability score of location j.
For example, using the map in FIG. 5 , we can advertise an ad at both locations A and C to fulfill an ad campaign with less expected prediction error than if we only advertised at location A. Further, we do not need to target a campaign equally towards each location in the group. We can use various combinations of locations in order to meet both desired traffic volume and predictability requirements.
According to features and principles of the present invention and as illustrated in FIG. 6 , an exemplary system 600 for predicting traffic may include a storage device 602 , a processor 604 , a network 606 , a computer 608 , and a computer 610 . Processor 604 may be coupled to storage device 602 and network 606 . Network 606 may be coupled to computers 608 and 610 . Storage device 602 may be implemented using hard drives, floppy disks, ROM, RAM, and/or any other mechanisms for saving data. Processor 604 may be implemented using computers, application-specific integrated circuits, CPUs, and/or any other device that is capable of following instructions and/or manipulating data. Network 606 may be implemented via the Internet, wide area networks, local area networks, telephone networks, and/or any other mechanism that can facilitate remote communications. Computers 608 and 610 may be personal computers, desktops, mainframes, and/or any other computing device.
According to features and principles of the present invention, system 600 may be configured to implement exemplary method 700 , illustrated in FIG. 7 , for predicting traffic. Processor 604 may receive historical traffic data for a location (step 702 ). The historical traffic data may be stored on storage device 602 . Historical traffic data may include any information about previous traffic volume at the location. If the location is a website on network 606 , the historical traffic data may include a number of visitors to the website via computers 608 or 610 , a number of hits at the website, a number of impressions at the website, and/or any other data about the website for various times of the day.
Particularly, the historical traffic data may include observations of the traffic volume x i,k at the website at each hour k of day i for any number of days. The observations may be made by processor 604 , counters at the website, or any other mechanism. Besides websites, the location may be any other place where traffic passes through or attendance can be measured and/or observed. For example, a location may be a highway, a street, a television channel, a radio station, or any other place where traffic information is obtainable.
Consistent with features and principles of the present invention, processor 604 may identify one or more time-dependent parameters based on the historical traffic data (step 704 ). For example, processor 604 may estimate the parameters â k , {circumflex over (b)} k , {circumflex over (x)} k , {circumflex over (x)} i,k , {circumflex over (x)} i,k,z , {circumflex over (σ)} k , {circumflex over (σ)} k 2 , {circumflex over (Δ)} k , {circumflex over (d)} z , x k , e k , or other time-dependent parameters using historical traffic data. Processor 604 may estimate the time-dependent parameters using ordinary least squares or other methods, as previously described.
Processor 604 may compute a traffic volume prediction (step 706 ), consistent with features and principles of the present invention. The prediction may be computed using any of the methods discussed herein and it may be the predicted traffic volume for the next hour, day, time niche, or other time period. Processor 604 may then compare the prediction against actual measured traffic volume data (step 708 ). The actual traffic volume data may reflect visits, hits, etc. by users at a location (e.g., website) via computers 608 or 610 . In one embodiment, processor 604 may make the comparison by calculating e i,k .
Consistent with features and principles of the present invention, processor 604 may then compute a predictability score for the location (step 710 ). The predictability score may be a normalized L1 score, a mean error, a maximum error, a minimum error, or any other metric. When e i,k is calculated, the computed predictability score may also be based on e i,k .
Additionally, processor 604 may perform steps 702 to 710 to compute a predictability score of another location. System 600 may execute an ad campaign based on the predictability scores of the two locations using an exemplary method 800 illustrated in FIG. 8 . For example, processor 604 may compare the predictability scores of the two locations (step 802 ) and generate a predictability map (step 804 ). From the predictability map and/or the predictability scores, processor 604 may select one of the two locations, a group comprising the two locations, and/or a larger plurality of locations for an advertising campaign (step 806 ). Processor 604 may conduct an advertising campaign at the selected location(s) by sending or placing advertisements at the locations (step 808 ). If the locations are websites, then processor 604 may display advertisements on the websites.
According to features and principles of the present invention, during the life of the ad campaign, processor 604 may adjust an advertising schedule of the ad campaign (step 810 ) to compensate for differences or variances between predicted and actual traffic. The advertising schedule may include the planned times and locations where processor 604 intends to place ads, as determined in steps 802 to 806 . As an ad campaign progresses, processor 604 may predict the traffic volume at various locations for a window of W days (e.g., processor 604 may predict the traffic volume for multiple hours at a website, as previously discussed). Processor 604 may then use the predictions to adjust the advertisement delivery schedule within the time window.
In the foregoing description, various features are grouped together in various embodiments for purposes of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed invention requires more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive aspects may lie in less than all features of a single foregoing disclosed embodiment. Thus, the following claims are hereby incorporated into this description, with each claim standing on its own as a separate embodiment of the invention. Furthermore, as used herein, the words “may” and “may be” are to be interpreted in an open-ended, non-restrictive manner. | Methods, systems, and articles of manufacture of the present invention may assist in planning, execution, and evaluation of advertising campaigns on the Internet. Particularly, methods, systems, and articles of manufacture of the present invention may help evaluate and/or predict traffic volume on the Internet. An exemplary method for predicting traffic may comprise receiving historical traffic data for a location, and computing a prediction of traffic volume for a particular time at the location using the historical traffic data and at least one prediction algorithm. | 50,569 |
FIELD OF THE INVENTION
[0001] The present invention relates to the method according to the preamble of claim 1 for doping and/or colouring glass, and especially to a method for doping glass, in which a two- or three-dimensional layer is formed of nanomaterial on the surface of the glass and allowed to diffuse and/or dissolve into the glass to change the transmission, absorption, reflection and/or scattering of electromagnetic radiation of the glass. In this context, colouring refers to doping glass in such a manner that the transmission or reflection spectrum of glass changes in the visible light region (approximately 400 to 700 nm) and/or ultraviolet region (200 to 400 nm) and/or near infrared region (700 to 2000 nm) and/or infrared region (2 mm to 50 mm). According to the invention, glass can be coloured in such a manner that a nano-sized material (size below 100 nm in two or three dimensions) is directed to the surface of glass, the temperature of which is at least 500° C., and the material consists of at least a glass-colouring compound, such as a transition metal oxide, and an element or compound that lowers the melting temperature of the oxide, such as an alkali metal oxide. The material dissolves and/or diffuses on the surface of glass and dopes it in such a manner that it turns into the colour characteristic of the colouring compound.
[0002] So as to be able to colour glass efficiently, i.e. in a sufficiently short time, at a temperature of 500 to 800° C., the material used in the colouring must be in nanosize. There are two reasons for this. Firstly, the diffusion rate of particles in a medium depends essentially on the size of the particles, and typically, the diffusion rate of particles of 10 nm is three times faster than particles of 1 micrometer. Secondly, the surface area and surface energy required for colouring reactions is bigger when the material is in nanosize.
[0003] For the sake of clarity, it should be noted that the size of less than 100 nm in three dimensions refers to particles with a diameter of less than 100 nm, and the size of less than 100 nm in two dimensions refers to thin films with a thickness of less than 100 nm. In the following, the text refers mainly to nano-sized particles, but the invention can also be applied using thin films.
[0004] The method of the invention can be used to colour flat glass, packing glass, utility or household glass, and special glass, such as optical fibre blanks.
DESCRIPTION OF THE PRIOR ART
[0005] Colouring glass refers on a wide scale to altering the interaction between glass and electromagnetic radiation directed to it in such a manner that the transmission of the radiation through the glass, reflection from the surface of the glass, absorption into the glass, or scatter from the components in the glass changes. The most important wavelength regions are the ultraviolet region (e.g. preventing ultraviolet radiation of sun through glass), the visible light region (altering the colour of glass visible to the human eye), the near infrared region (altering the transmission of sun infrared radiation, or glass material used in active optical fibres), and the actual infrared region (altering the transmission of heat radiation).
[0006] Glass can be coloured in many different ways. Most typically, glass is coloured by adding into molten glass or its raw materials compounds of colour-producing metals, such as iron, copper, chromium, cobalt, nickel, manganese, vanadium, silver, gold, rare earth metals, or the like. Such a component will cause absorption or scattering of a certain wavelength region in the glass, thus producing a characteristic colour in the glass. However, adding a colouring substance in molten glass or raw materials makes changing the colour an extremely expensive and time-consuming procedure. Therefore, the manufacture of especially small batches of coloured glass is expensive.
[0007] Nickel oxide is used in colouring glass grey. When glass is made with a float process, the molten glass web runs on a tin bath. To prevent the tin bath from oxidizing, there is a reducing gas atmosphere on the tin bath. However, this causes nickel to reduce on the surface of glass, whereby metal nickel is formed on the surface of glass and creates a gauze or veil on the surface, which weakens the quality of the glass. To eliminate this problem, nickel-free grey glass compositions have been developed, such as the one disclosed in U.S. Pat. No. 4,339,541. The method is thus still based on colouring molten glass entirely.
[0008] U.S. Pat. No. 4,748,054 discloses a method for colouring glass with pigment layers. In this method, glass is sandblasted and different enamel layers are pressed on it to be then attached to the surface by burning. However, the chemical or mechanical wear resistance of such a glass is poor.
[0009] U.S. Pat. No. 3,973,069 discloses an improved method of colouring glass with diffusion. The improvement is provided with electric potential. The patent describes as a known method a method for colouring glass with colour metal ion diffusion in such a manner that glass is brought into contact with a medium that contains colouring ions, and the ions then diffuse from the medium to the glass. The glass colouring mechanism is then specifically based on the diffusion of ions and not on the diffusion of a nano-sized material with the glass. Similarly, the diffusing substance is not an oxide, but a metal ion. The patent only refers to colouring glass with silver. However, this colouring mechanism is not a pure diffusion, but an ion exchange reaction (silver/sodium ion).
[0010] U.S. Pat. No. 5,837,025 discloses a method for colouring glass with nano-sized glass particles. According to the method, glass-like, coloured glass particles are made and directed to the surface of the glass being coloured and sintered into transparent glass at a temperature of less than 900° C. The method differs from the present invention in that in the present invention, the particles diffuse inside glass and do not form a separate coating on the surface of the glass.
[0011] Finnish Patent FI98832, a method and device for spraying material, discloses a method that can be used in doping glass. In this method, the material being sprayed is directed in liquid form into a flame and transformed into droplets with the aid of a gas essentially close to the flame. This produces extremely small particles that are a nanometre in size quickly, inexpensively and in one step. The patent does not, however, describe the size of the produced liquid droplet. Neither does the patent describe the interaction between the produced particles and glass material.
[0012] Finnish patent FI114548 describes a method for colouring glass with colloidal particles. The patented method uses a flame spraying method to transport colloidal particles to the material being coloured. In the method, it is also possible to add other components to the flame, such as a glass-forming liquid or gaseous material, which assist the formation of correct-sized colloidal particles in the material. The patent does not state any other functions for the glass-forming liquid or gaseous material.
[0013] When using the method described in FI98832 for colouring glass, it has been found that a gauzy curtain may appear on the surface of the glass especially when colouring the glass in low temperatures of less than 700° C. The gauze is assumed to be due to crystalline areas remaining on the surface of the glass, whose proportion on the surface increases with the temperature difference between the melting point of the colouring component and glass surface. In cobalt oxide, whose melting point is 1795° C., the crystalline portion is larger than in iron oxide, whose melting point is 1369° C. or 1594° C. depending on the crystal form. In copper oxide, whose melting point is 1235° C. or 1326° C. depending on the crystal form, the crystalline portion is even smaller than in iron oxide.
[0014] When colouring glass with the method of FI98832 or some other method, in which the colouring is based on the diffusion and dissolution into glass of nanoparticles (particle diameter less than 100 nm), the colouring should, for economic reasons, be done when the temperature of the glass is 500 to 650° C. The colouring can then be done in a float line between the tin bath and cooling oven (temperature 550 to 630° C.) or in a glass tempering line (temperature approximately 620° C.). Colouring must then not produce crystal-line and/or gauzy areas on the surface of the glass.
SUMMARY OF THE INVENTION
[0015] It is thus an object of the present invention to provide a method for doping and/or colouring glass in such a manner that the above-mentioned prior-art drawbacks are eliminated. The object of the invention is achieved by a method according to the characterising part of claim 1 , which is characterised in that the layer of nanomaterial contains at least one component that provides the above-mentioned change, and at least one component that lowers the melting point of the component providing the above-mentioned change.
[0016] With the method of the present invention, glass can be coloured when the temperature of the surface of the glass is higher than 500° C.
[0017] The present invention is based on the idea that a nano-scale material is directed to the surface of the glass, the material consisting of at least two components: a metal compound providing a characteristic colour for the glass and a component lowering the melting point of the metal compound.
[0018] The lowering of the melting point of the compound can also take place in such a manner that the nanomaterial has components that trans-form the metal compound providing a characteristic colour into an amorphous form in the nanoparticle.
[0019] The lowering of the melting point of a compound can also take place in such a manner that the metal compound providing a characteristic colour and the component lowering the melting point of the compound are in different nanoparticles or films that are brought into contact with each other to produce essentially the same outcome as when these components are in the same nanoparticle or film.
BRIEF DESCRIPTION OF THE FIGURES
[0020] The invention will now be described in greater detail by means of preferred embodiments and with reference to the attached drawings, in which
[0021] FIG. 1 is a flow chart showing an implementation method of the invention, and
[0022] FIG. 2 shows equipment used in implementing the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The present invention relates to a method for colouring glass in a wavelength region that extends from ultraviolet radiation to infrared radiation. The temperature of the glass being coloured is above 500° C. The invention is based on directing to the surface of the glass a material less than 100 nanometres in size and consisting of a metal compound that provides a characteristic colour for the glass and a component that lowers the melting point of the metal compound.
[0024] Combinations of the colouring metal compound and the component lowering its melting point include CoO—V 2 O 5 , CoO—CaO, CoO—B 2 O 3 , Cu 2 O—PbO, Cu 2 O—SiO 2 , CoO—SiO 2 , CoO—TiO 2 , MnO—SiO 2 , MnO—Al 2 O 3 —SiO 2 , MnO—Al 2 O 3 —Y 2 O 3 —SiO 2 , Fe 2 O 3 —P 2 O 5 , and Mno—P 2 O 5 . It is apparent to a person skilled in the art that there are numerous compounds of this type and that the melting point of the compounds is lower than that of the colouring compound possibly only in some mixture ratios. The best result is obtained when the components form a eutectic mixture ratio, but the formation of such a eutectic mixture ratio is not necessary.
[0025] The nano-sized material essential for the present invention can be produced in many ways, such as with a flame method, laser ablation, sol-gel method, chemical vapour phase deposition (CVD), physical vapour phase deposition (PVD), atom layer deposition (ALD) method, molecular beam epitaxy (MBE) method, or the like. The following presents the use of a hot aerosol layering method to produce the material of the invention.
[0026] According to the flowchart of FIG. 1 , the method of the invention forms a flame in step 11 . In this context, the term ‘flame’ refers to any method of producing a high, local temperature. These include a fuel/oxygen flame, a plasma flame, an electric arc, or a high temperature provided with laser heating.
[0027] In step 12 , a liquid raw material, for instance, is directed to the flame or close to it. The liquid raw material contains a metal compound that as a result of a chemical reaction or vaporisation/condensation in the flame produces nano-sized particles that contain a glass-colouring metal compound, typically metal oxide. The raw material fed into the flame in step 12 also contains a starting material that as a result of the chemical reaction and/or vaporisation/condensation in the flame produces nano-sized particles that contain a component that lowers the melting point of the compound of the glass-colouring metal compound. The nanoparticles created in step 12 can be particles that contain both the glass-colouring metal compound and the component that lowers the melting point of the metal compound. The nanoparticles created in step 12 can be crystalline or amorphous, as long as the melting temperature of the produced material is lower than that of the glass-colouring metal compound.
[0028] In the next step 13 of the method, at least one liquid component is transformed into droplets in such a manner that the formed droplets contain the colouring component, or a reaction in which the colouring component has partaken, the second component created as a result, or a compound of these two. Said droplets can preferably be made to contain said colouring component, if the colouring component is already dissolved in the liquid being made into droplets when it is fed into the flame.
[0029] It is essential for an efficient formation of nanoparticles created in the flame that the sprayed liquid material is brought into the flame in very small droplets. If the liquid material is brought into the flame in larger droplets, the process produces not only nanoparticles, but also larger particles that will not dissolve into the glass being coloured, and thus weaken the quality of the glass. The optically measured diameter of the droplets being created must therefore preferably be less than 10 micrometers, more preferably less than 6 micrometers, and most preferably less than 3 micrometers. The droplets can be produced by using generally known atomisation methods, such as gas-distributed atomisation, pressure atomisation, or ultrasound-based atomisation.
[0030] In the next step 14 of the method, the droplets and the components contained therein are evaporated and condensated, whereby the condensated components form ultra-small particles either through chemical reactions, mainly oxidisation reaction, or through nucleation/condensation. Evaporation and condensation can preferably be done with the heat of the flame or with an exothermally reacting solvent.
[0031] The composition, content, and size distribution of the created particles can be controlled by adjusting the operating parameters of the method, such as the temperature of the flame, flow rates of the gases, composition of the components fed to the flame, interrelations and absolute quantities of the components. Controlling the size distribution of the created particles is important, because the size of the particles plays a significant role in successful colouring of glass. It is especially essential that all particles be created through evaporation-nucleation, whereby no large residual particles are created in the process. The creation of residual particles can be avoided, if the droplet size of the liquid being sprayed is sufficiently small.
[0032] The particles created in the last step 15 of the method are brought into contact with the material to be coloured. The particles collect on the surface of the glass to be coloured mainly due to diffusion and thermophoresis. Owing to the large specific area of the particles, they diffuse and dissolve into the glass and provide to the glass a colour that is characteristic of the metal or metals in the particles. Due to the components that lower the melting point of the metal compounds in the particles, no crystalline or gauzy areas are formed in the glass, which would weaken the quality of the glass.
[0033] FIG. 2 shows equipment for colouring glass with the method of the invention. The shown equipment is a flame spraying apparatus based on a flame provided by burning gas, but it is clear to a person skilled in the art that instead of a gas flame, the heat source (thermal reactor) can also be a plasma flame, for instance.
[0034] The equipment 20 comprises a nozzle 21 that forms a flame 29 for spraying the colouring component 27 . The nozzle is preferably made up of nested pipes 22 a, 22 b, 22 c, 22 d, through which the components used in the spraying can be conveniently brought to the flame 29 .
[0035] To produce the flame 29 , a combustion gas, such as hydrogen, is brought to the nozzle 21 from container 23 b through pipe 22 b serving as a feed channel. Correspondingly, the oxygen required for producing the flame is brought from container 23 c to feed pipe 22 c. Feed pipe 22 c can be connected to feed pipe 22 b, if a premixed flame is to be used. The combustion gas and oxygen flowing through the nozzle S form the flame 29 . To control reactions in the flame or in its vicinity, it is also possible to feed a protective gas to the process from container 23 a through feed channel 22 a.
[0036] For the sake of simplicity, FIG. 2 only shows a situation, in which the component essential for colouring and the component essential for the formation of the eutectic mixture or partially eutectic mixture are already mixed or dissolved into the liquid to be atomised in container 23 d. Possible modifications to the device, such as arranging more liquid feeds, vapour feeds, or gas feeds by increasing the number of nested or adjacent pipes, or by connecting more containers to the same inlet, or by bubbling the component with combustion gases or a protective gas, are apparent to a person skilled in the art.
[0037] In the device of FIG. 2 , the liquid to be sprayed is fed from chamber 23 d to supply channel 22 d. Along the supply channel, the liquid is directed to the nozzle S that sprays it and is shaped in a manner known per se to achieve the desired flow properties. The liquid flowing through the nozzle S is made into droplets 28 preferably with a gas flowing from supply channel 22 b . To achieve an as efficient droplet-to-nanoparticle transformation as possible, the diameter of the droplets must be at most 10 micrometers. Under the thermal energy released from the flame 29 , the droplets 28 form particles 27 that are preferably directed to the glass being doped. Owing to the large specific area of the particles, they diffuse and dissolve into the glass and produce into the glass the colour characteristic of the metal or metals in the particles. Due to the components that lower the melting point of the metal compounds in the particles, no crystalline or gauzy areas are formed in the glass, which would weaken the quality of the glass.
[0038] The equipment 20 also comprises a control system 26 for controlling the operating parameters of the equipment in such a manner that as the droplets 29 and their contents evaporate and react/nucleate, the properties, such as content and particle size distribution, of the created particles 27 can be controlled.
EXAMPLES p In the following, the invention will be described in more detail with examples.
Example 1
Colouring Glass Blue with Cobalt
[0039] It is known that cobalt oxide and silicon oxide form a eutectic mixture whose melting point is approximately 1377° C., i.e. approximately 400° C. lower than that of cobalt oxide. Such a mixture contains approximately 75% cobalt oxide and 25% silicon oxide.
[0040] The raw material of cobalt oxide was prepared by dissolving 25 g cobalt nitrate hexahydrate, Co(NO 3 ) 2 •6H 2 O, into 100 ml methanol. This solution was fed to middle channel 22 d of the flame spraying equipment shown in FIG. 2 at 10 ml/min. The flame spraying equipment was positioned in such a manner that forming droplets and particles took place in an oven having a temperature of 600° C. Droplets were formed from the liquid by feeding hydrogen gas into channel 22 b at a volume flow of 20 l/min, whereby the speed of the hydrogen gas at the nozzle S was approximately 150 m/s. The fast hydrogen gas flow formed droplets of less than 10 micrometers of the liquid flow. Nitrogen gas was fed from channel 22 c at a flow rate of 15 l/min. Some of the nitrogen gas, approximately 5% of the volume flow, was first directed from feed bottle 23 c through a bubbler. The bubbler contained silicon tetrachloride, SiCl 4 , that evaporated with the nitrogen gas flow. After this, the nitrogen flow containing evaporated silicon tetrachloride was combined with the rest of the nitrogen flow and directed to channel 22 c. The temperature of silicon tetrachloride was adjusted so that silicon tetrachloride produced, in comparison with the cobalt nitrate flow, such a mass flow that the ratio of cobalt oxide and silicon oxide created in the process was 3:1. Oxygen gas was fed to channel 22 a at a volume flow of 10 l/min. The raw materials reacted in the flame and formed CoO—SiO 2 nanoparticles having an average diameter of approximately 30 nm. The particles partially agglomerated into particle chains. The particles were directed to flat glass that moved at a speed of 0.2 m/min in the 600-degree oven. The distance of the flame spraying equipment nozzle S from the surface of the glass was 155 mm. After the coating, the tensions in the glass were removed by keeping the glass for 15 minutes at a temperature of 500° C., after which the glass was cooled to room temperature during three hours. After the cooling, it could be seen that the glass had turned blue, and there was no gauze or crystalline materials in it.
Example 2
Colouring Glass Grey with Nickel
[0041] It is known that nickel oxide, NiO, and vanadium pentoxide, V 2 O 5 , form a mixture whose melting point at every mixture ratio is lower than the melting point of nickel oxide. In the exemplary test, nanoparticles were prepared containing approximately 60% nickel oxide and 40% vanadium pentoxide. The melting point of such a material is approximately 900° C., i.e. approximately 1000° C. lower than that of nickel oxide.
[0042] The raw material of nickel oxide was prepared by dissolving 25 g hexahydrate of nickel nitrate, Ni(NO 3 ) 2 •6H 2 O, into 100 ml ethanol. The raw material of vanadium pentoxide was prepared by dissolving 2.9 g vanadium chloride, VCl 2 , into 100 ml ethanol. The solutions were then mixed together. This solution was fed to middle channel 22 d of the flame spraying equipment shown in FIG. 2 at 10 ml/min. The flame spraying equipment was positioned in such a manner that forming droplets and particles took place in an oven having a temperature of 600° C. Droplets were formed from the liquid by feeding hydrogen gas to channel 22 b at a volume flow of 20 l/min, whereby the speed of the hydrogen gas at the nozzle S was approximately 150 m/s. The fast hydrogen gas flow formed droplets of less than 10 micrometers of the liquid flow. Oxygen gas was fed to channel 22 a at a volume flow of 10 l/min. The raw materials reacted in the flame and formed NiO—V2O5 nanoparticles having an average diameter of approximately 30 nm. The particles partially agglomerated into particle chains. The particles were directed to flat glass that moved at a speed of 0.2 m/min in the 600-degree oven. The distance of the flame spraying equipment nozzle S from the surface of the glass was 155 mm. After the coating, the tensions in the glass were removed by keeping the glass for 15 minutes at a temperature of 500° C., after which the glass was cooled to room temperature during three hours. After the cooling, it could be seen that the glass had turned grey, and there was no gauze or crystalline materials in it.
[0043] It is apparent to a person skilled in the art that as technology advances, the basic idea of the invention can be implemented in many ways. The invention and its embodiments are thus not limited to the examples described above, but may vary within the scope of the claims. | The invention relates to a method for doping and/or colouring glass. In the method a two- or three-dimensional layer is formed on the surface of the glass, and the layer is further allowed to diffuse and/or dissolve into the glass to change the transmission, absorption, reflection and/or scattering of the electromagnetic radiation of the glass. The layer of nanomaterial includes at least one component that causes the above-mentioned change and at least one component that lowers the melting point of the above-mentioned component causing the change. | 25,441 |
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