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EP-0490015-B1 | 490,015 | EP | B1 | EN | 19,940,202 | 1,992 | 20,100,220 | new | B65B11 | B65D71, B65B53 | B65D71, B65B53, B65B11 | B65D 71/08, B65B 11/58, B65B 53/00 | Procedure for cold-packaging and shrinkwrapping groups of products | This procedure forms a shrinkwrapping by placing two wrapping strips (3, 4) around the perpendicular axes of the group of products (1) by passing a film of material (2), that is partially stretched during the procedure so that it will cling easily and which when pulled will lengthen and shrink in width without tearing; one of the afore-mentioned wrapping strips (4) is then wrapped around the shorter horizontal axis of the group of products (1) and the top can be used as a carrying handle (5). | This invention describes a procedure for packaging and shrinkwrapping groups of products. With the techniques currently available on the market, most packs for packaging groups of products, such as cans or bottles of drinks are comprised of strips of heat-shrinkwrapping material. The advantage of these packs enabling individual loose products to be grouped, so that they are easier to handle and move, is that they are easy to manufacture, a film of heat-shrinkwrapping material is simply wound round the group of products, usually around the longer horizontal axis of the group, which is then passed through an oven where the wrapping is shrunk. So when the group leaves the oven it is already firmly wrapped and no further operations are needed. The main disadvantage of this kind of wrapping is financial: the wrapping film has to be fairly thick to support the weight of the group of products and the force of heat-shrinkwrapping without tearing involves some expense and wasted materials. A further disadvantage of this kind of wrapping is that it does not have a handle for carrying or moving the groups of products around. The simplest way of handling them is either by gripping the pack at the edge of the side openings or by making holes in the wrapping with the tips of the fingers, but this is rather difficult because the wrapping film is tough. In order to overcome this disadvantage some wrapping strips have been designed that can have a handle attached to them on the outside. This is quite a good idea for machine operators having to move the wrappings around, but it is very expensive for the manufacturer who requires a more complex and consequently more expensive machine. To overcome these problems the US-A-4596330 pubblication proposes a package comprising a pair of circumferentially continuous bands or tubes made from elastic plastic film of materials capable of being highly stretched below the elastic limits thereof. The band with horizontal axis makes also the function of handle. The material is applied without the necessity to be heated. During the application of the first (with vertical axis) band the products, that are to be packed, have the tendency to roll or slide and it is required particular care in the handling of this partially completed package; however the stretching of the ring bands and the applying phase of the same around the bottles is not an easy and simple procedure. It is, therefore the purpose of this invention to overcome the afore-mentioned disadvantages. In the form of the claims characterising it, this invention overcomes this disadvantage with a procedure using a double wrapping strip that also forms a carrying handle. One of the advantages of this invention is that it is simple to manufacture, consisting of a few simple stages, such as holding back the group of products and wrapping them in a partially stretched film of material that will cling easily and stretch without tearing. A further advantage of this invention is that it is inexpensive because the materials are relatively thin and do not require an oven. This invention is subsequently explained in greater detail in the following description with the diagrams enclosed, these being only one example of the invention and not to be interpreted as being in any way restrictive. Figures 1 to 5 are perspective drawings showing the different stages of the procedure in the terms of this invention. With reference to the enclosed figures, the procedure in the terms of this invention consists of the following steps: holding the group of products, 1, by their two opposite sides; using the film of material, 2, which clings easily and which when pulled will lengthen and shrink in width without tearing to form the first wrapping, 3, of said group of products around one of its perpendicular axes at the sides where it is being held; slightly pulling by permanently tightly stretching the film, 2, forming the first wrapping, 3; releasing the group of products, 1, and holding it by the other two sides at right-angles to the previous ones; using the film of material, 2, to form the second wrapping, 4, of the same group around the axis at right-angles to the previous sides where it is being held; slightly pulling by permanently tightly stretching the film, 2, forming the second wrapping, 4. Wrapping, 3, around the vertical axis is formed by ensuring that the film, 2, protrudes slightly beneath the group of products, 1, so that when wrapping is complete, it will act as a partial support for the products, 1. Whereas wrapping, 4, is around the horizontal axis, preferably the shorter one, so that it forms a carrying handle , 5, as shown in Figure 5. Shrinkwrapping formed in this way (see Fig. 5) consists of two wrapping strips, 3 and 4 (of one or more turns) of material that will cling easily and which when pulled will lengthen and shrink in width without tearing. Wrappings, 3 and 4, are overlapping and angled so as to be almost at right-angles to each other. The top of wrapping, 4, is on the horizontal axis and forms a carrying handle, 5. In its ideal form, as shown in the enclosed figures referring to bottles of drinks, 1, the group of bottles, 1, is held at the bottom by elevators, 6, and at the top by vertical pressers, 7, once the first strip of film, 2, marked 3a in Fig.1, is inserted between at least two bottles, 1. In the diagram the bottles, 1, are arranged in two lengthways rows, and the strip, 3a, is inserted between the two rows of bottles, 1, (see Figure 1, arrow f₁). The film, 2, is then wrapped around the bottles, 1, as it comes from the reel, 9, turning three times around the vertical axis of the group of bottles (see Fig. 2, arrow f₂); as can clearly be seen in Fig. 2, rotation of the reel, 9, is shown in four intermediate positions marked 9a, 9b, 9c and 9d. The first of these turns of the film, 2, is effected with the film only slightly stretched, while the second and third turns of the film are subject to stretching (usually by pulling) to what may be as much as 300% of its initial length; this operation is shown in the diagram in Fig. 2, where the strip, 3s, of the film, 2, has been stretched starting from position 9d of the reel, 9. Next the film, 2, is cut and the elevators and pressers, 6 and 7, are lowered or raised from the bottles, 1, (see Fig. 3, arrows f₃ and f₄), and wrapped in this way, they are fed to the next wrapping station (see Fig. 3, arrow f₅). As this figure shows, the wrapping, 3, protrudes slightly from underneath the edges of the bottles, 1, so that once the film, 2, is cut and the wrapping, 3, is no longer being pulled, it is released, becoming shorter and shrinking beneath the bottles, 1, thus acting as a support and clinging to them. The group of bottles, 1, is then held and supported by two horizontal pressers, 8, pressing on the longer vertical sides and strip, 4a, of the film, 2, the same as the previous strip, but preferably being wound from the second reel, 10, is brought into contact with the wrapping, 3, beneath the bottles, 1, (see Fig. 4, arrow f₆). As the film, 2, is made of material that clings easily, this will be sufficient to ensure that the strip, 4a, clings tightly to the wrapping, 3, and does not become unstuck while the reel, 10, makes three turns around the shorter diagonal horizontal axis of the group of bottles, 1, (see Fig. 2, arrow f₇). As in the previous case the first turn is effected with the film only slightly stretched, while the second and third turns are subjected to the afore-mentioned stretching in position 10d from the reel, 10. Finally the film, 2, is cut and as the top of the wrapping, 4, forms a strip of limited width, it can also act as the carrying handle, 5. The film material, 2, is such that the handle, 5, becomes slightly longer when the bottles, 1, are picked up, as shown in Fig. 5, but shrinks again once it is released, so the shrinkwrapping will cling to the bottles, 1, again so that they will not move in any way. As the material used for the film, 2, (polythene) is so thin that the three layers (two of which are stretched) are not even as thick as the 0.8 mm of the heat-shrinkwrapping materials, it is less expensive. A further advantage of this procedure is that no heat treatment is required so the machine being used is simpler, so many of the usual problems involved with shrinking ovens can be avoided. In fact, this packing procedure is particularly suited to products likely to suffer damage from large changes in temperature. There are countless variations to this procedure: publicity leaflets can be inserted together with the film (these are usually transparent) during the first wrapping stage, the wrapping being held in place by the stretching of the subsequent turns of film; this saves the need for any further stages for the application of publicity materials. The group of bottles, 1, could be rotated on its own axis and the reel, 9 and 10, kept still as a consequence, or the wrapping stages could be reversed. | Procedure for wrapping groups of products disposed in side-by-side relationship by means of two stretching plastics material film wrappings (3, 4) applied around the products at a right angle one with respect to each other, characterised in that said procedure consists of the following stages: holding the group of products (1) by two opposite sides; forming a first (3) of said wrappings of at least two turns around the perpendicular axis to the sides where the group of products (1) is being held by continuously unrolling a film of material (2); permanently tightly stretching at least the second turn of film (2) forming the first wrapping (3) by pulling the film of material (2); releasing the group of products (1) and holding it by a second set of two opposite sides at right-angles to the previous ones; forming a second (4) of said wrappings of at least two turns around the axis at right-angles to the second set of opposite sides where the group of products (1) is being held by continuously unrolling the film of material (2); permanently tightly stretching at least the second turn of film (2) forming the second wrapping (4) by pulling the film of material. Procedure according to claim 1, characterised in that the film (2) is made of material that will cling easily and which, when pulled will stretch without tearing. Procedure according to claim 1, characterised in that one of the wrappings (3) is formed around the vertical axis, ensuring that the film (2) protrudes from underneath beyond the edges of the group of products (1). Procedure according to claim 3, characterised in that the initial strip (3a) of the vertical wrapping (3) is inserted, prior to the wrapping (3) being formed, between at least two of the groups of products (1). Procedure according to claim 1, characterised in that one of the two wrappings (4) is placed around the shorter horizontal diagonal axis of the group of products (1) thus forming a carrying handle (5) for the group of products (1). Procedure according to claim 5, characterised in that the initial strip (4a) of the horizontal wrapping (4) is placed underneath the group of products (1) prior to the wrapping (4) being formed. Procedure according to claim 1, characterised in that the first wrapping (3) is made around the horizontal axis. Procedure according to 1, characterised in that at least one of the first (3) and second (4) wrappings is formed by at least three overlapping turns of film (2) and characterised in that the second and third turns are subjected to pulling or tight stretching. | PRAS MATIC S N C DI ORSI MARIO; PRAS-MATIC S.N.C. DI ORSI MARIO & C. | GUIDETTI LUIGI; ORSI MARIO; GUIDETTI, LUIGI; ORSI, MARIO |
EP-0490016-B1 | 490,016 | EP | B1 | EN | 19,950,809 | 1,992 | 20,100,220 | new | H03G1 | H03G1, G05F3 | G05F3, H03F3, H03F1, H03G1 | H03G 1/00B4D, G05F 3/22C1, H03G 1/04 | Integrated circuit for generating a temperature independent current proportional to the voltage difference between a signal and a reference voltage | A circuit particularly useful in AGC systems, produces an output current (IOUT) which is proportional to the difference between a signal voltage (VAGC) and a reference voltage (VR) which is practically independent of temperature, by being a function of a ratio among actual values of integrated resistances and of a ratio among substantially temperature-stable voltages. The effects of temperature dependent value of integrated resistances and of temperature-dependent electrical characteristics of integrated semiconductor devices are compensated in order to produce the desired temperature-independent output current which may usefully be utilized for implementing an automatic gain control. | BACKGROUND OF THE INVENTION1. Field of the inventionThe present invention relates to an integrated circuit for the generation of a current proportional to the difference between a signal voltage and a reference voltage, and independent of temperature and of variations in the integrated resistors. The circuit is particularly useful, although not exclusively, for effecting automatic gain control in signal processing systems. Examples of gain controlled amplifiers having low temperature coefficients can be found in US-A-4 413 235 and in US-A-4 101 841. 2. Description of the prior artThe input signal of a signal processing system, especially if this comes from magnetic transducers, mechanical transducers, tuners, etc., can be subject to large amplitude variations. Variations of 30-60 dB can occur under various circumstances. It is therefore useful to equip the system for processing the signal with a device for automatic gain control, commonly denoted by the acronym AGC, which determines a variable amplification of the input signal so as to obtain an amplified signal with constant amplitude at the output. A typical simplified diagram of a system furnished with AGC is shown in Fig. 1. The signal at the input to the AGC circuit is a DC voltage VAGC, which is proportional to the amplitude of the signal Vx. The AGC circuit supplies an output current Iout which regulates the gain of the amplifier G, thereby keeping the amplitude of the signal Vx constant independently of the amplitude of the input signal VIN. On the other hand, integrated circuit components have highly temperature-dependent intrinsic electrical characteristics. Notably, the junction VBE in silicon is inversely proportional to temperature, while the value of an integrated resistor is directly proportional to temperature. In AGC systems and in analogous integrated circuits these variations in the electrical characteristics relative to the nominal design values, can often determine intolerable inaccuracies in the operation of these very sensitive circuits. OBJECT AND SUMMARY OF THE INVENTIONHence it is a main aim of the present invention as defined in the appended claims, to provide an integrated circuit capable of generating a current proportional to the difference between a signal voltage and a reference voltage, and which is substantially independent of temperature variations. A further aim of the invention is to provide an improved AGC circuit. The circuit of the invention for generating a current proportional to the difference between a signal voltage and a reference voltage, and independent of temperature, comprises a differential input circuit having a first input terminal to which is applied the signal voltage and a second input terminal to which is applied a reference voltage stable relative to temperature. The circuit is formed from a pair of transistors connected in a common-emitter configuration, and each transistor is biased by means of an individual current generator connected between a first circuit supply node and the emitter of the relevant transistor. The two current generators are substantially identical and essentially deliver a current inversely proportional to a certain integrated resistor value (i.e. inversely proportional to the temperature coefficient of the integrated resistors) and the emitters of the two transistors are connected across an integrated resistor in order to raise the value of the trigger threshold of the differential, thereby increasing the zone of linearity in order to secure the conversion of the potential difference between the signal voltage and the reference voltage into a difference between the currents flowing through the two branches of the differential circuit. Between a second (virtual) supply node and the respective collectors of the two transistors of the differential input circuit, are connected two identical, forward-biased diodes which respectively function as load for the respective transistor. In this way, a differential voltage, which represents a current/voltage conversion, in accordance with a logarithmic law, of the currents which flow through the two branches of the differential circuit, is obtained between the output (collector) nodes of the differential input circuit. This differential voltage is applied to the inputs of a first differential stage, across which is forced a bias current generated by circuit means which are able to generate a current directly proportional to temperature and inversely proportional to the value of at least one integrated resistor. These circuit means for generating a current proportional to temperature and inversely proportional to the value of an integrated resistor can be various. According to a preferred embodiment, a bias current with these characteristics can conveniently be derived from a common band-gap circuit which is normally present in integrated circuits for signal processing, being widely used as source of a constant voltage with value substantially independent of temperature variations and of the supply voltage, as is well known to the expert. The differential output voltage produced by such a first differential stage is applied to the inputs of a second differential stage able to carry out a voltage/current conversion, in accordance with an exponential law, in order to generate the desired output current across an output terminal, as a function of the differential voltage applied to the individual inputs. This second differential stage is biased by means of a generator of constant current which is essentially independent of temperature variations. The output current is equal to the product of the value of said constant bias current of the second differential stage, and which is independent of temperature variations, and of an exponential function of a ratio between integrated resistors (which is therefore substantially invariable with respect to temperature), of the logarithm of a pure number and of the ratio between voltages which are substantially temperature-stable, as will be demonstrated in more detail later. BRIEF DESCRIPTION OF THE DRAWINGSThe various aspects and advantages of the circuit which is the subject of the present invention will become clearer through the following description and reference to the attached drawings in which: Fig. 1 is, as already described, a simplified block diagram of a system for automatic gain control (AGC); Fig. 2 is a functional block diagram of the circuit of the invention; Fig. 3 is a circuit diagram according to a preferred embodiment of the circuit of Fig. 2; Fig. 4 is a circuit diagram of a circuit generating a current proportional to temperature and inversely proportional to the value of an integrated resistor, alternatively usable in the circuit of the invention of Fig. 3. DESCRIPTION OF THE PREFERRED EMBODIMENTWith reference to Fig. 2, the circuit of the invention operationally comprises a first block A which performs a linear/logarithmic conversion of the differential voltage VAGC- VR into currents I₁ + x and I₁ - x. The block B performs a current/voltage conversion in accordance with a logarithmic law of the currents I₁ + x and I₁ - x into the differential voltage Vd. The block C is a first differential stage across which is driven a bias current I₂ generated by a circuit able to generate such a current I₂ directly proportional to temperature and inversely proportional to the value of at least one integrated resistor. This circuit can be a band-gap circuit (B.G.). The block C operationally performs a voltage/voltage conversion, in accordance with an exponential law, of the differential voltage Vd applied to the inputs, into a differential output voltage VD. The block D is a second differential stage, across which is driven a bias current IEE, which is essentially independent of temperature. Operationally, the block D performs a voltage/current conversion, in accordance with an exponential law, between the differential voltage VD applied to the individual inputs, into an output current IOUT which is a function of the difference between the voltages VAGC and VR and independent of temperature variations. A preferred embodiment of the invention is represented by the circuit of Fig. 3, in which the relevant circuit blocks A, B, C, D and B.G. are identified by means of frames executed with dashed lines. A typical band-gap circuit (B.G.) consists of the transistors T6, T7, T8, T9, T10 and T11 and of the resistors RA, RB, RC and RD. This circuit is commonly present in integrated circuits in that it is widely used to produce, on the respective output terminal, a constant voltage VG, which is extremely temperature-stable and independent of variations in supply voltage. The current across the transistors T6 and T7 of the band-gap circuit can be mirrored, by means of a transistor T5, and it can be demonstrated that this current I2 is given by the relationship: I₂ = KTqRA ln A where K is Boltzman's constant, q is the electron charge, T is the temperature in degrees Kelvin and A is the area of the transistor T8. The resistors R connected between the emitters of the transistors T6, T7 and T5 can optionally be introduced with the aim of increasing the precision of the mirroring ratios, in accordance with an art well known moreover to the expert. According to this preferred embodiment, a band-gap circuit is therefore exploited in order to generate a bias current I₂ essentially proportional to temperature (T) and inversely proportional to the value of at least one integrated resistor (RA), which current is forced across a first differential stage (block C) formed by the transistors T3 and T4 and by the relevant load resistors R₂. The second differential stage, or differential output stage (block D), is composed of the transistors T12 and T13 and of the relevant bias current IEE generator which is essentially independent of temperature. Numerous temperature-independent current generating circuits are fully described in the literature. The work entitled Analysis and Design of Analog Integrated Circuits by P.R. Gray, R.G. Meyer, Publisher J. Wiley & Sons 1984, second edition, contains, appendix A/3 on pp. 284-296, a description of numerous temperature-independent current and voltage generating circuits, which description is incorporated here for express reference. Other circuits of this type are moreover well known to the expert and hence a repeated description of these circuits is superfluous. The differential input circuit (block A) is composed of the pair of transistors T1 and T2, of the integrated resistor R₁ connected between the emitters of the two transistors and of the pair of current I₁ generators able to supply a current given by the following relationship: I₁ = VREFREwhere VREF is a constant, temperature-independent voltage and RE is an integrated resistor, the value of which is hence subject to temperature variations. As will be clear, a suitable voltage VREF will be able to be conveniently derived from the voltage VG available, within the integrated circuit, on the respective terminal of the band-gap circuit (B.G.). The block B represents the respective loads of the two transistors T1 and T2 of the differential input circuit, D1 and D2, respectively. The two diodes D1 and D2 are respectively connected to the respective collectors of the two transistors T1 and T2 and to a virtual supply node of the circuit. The resistor RV has the sole effect of producing a voltage drop sufficient to maintain the pair of transistors T3 and T4 of the first differential stage (block C) in an appropriate zone of the dynamic operating characteristic. ANALYSIS OF THE OPERATION OF THE CIRCUITIn comparing a temperature-stable reference voltage VR (which can be derived from the constant voltage VG supplied by the same band-gap circuit) with a signal voltage VAGC, and if the condition: R₁ I₁ >> VT (where VT = KTq ) is valid, it is possible to write: VAGC - VRR₁ = x The differential voltage Vd at the input of the first differential stage T3-T4 (block C) is given by the difference between the VBE of the diodes D1 and D2: Vd = VBE1 - VBE2 = VT ln I₁ + xI₁ - xThe equation which links the current y to the differential input voltage of the differential Vd is as follows: y = I₂2 tanh Vd2VTSubstituting (4) into (5) gives: y = I₂2VAGC - VRR₁ I₁Then substituting equation (1) for I₂ and equation (2) for I₁, gives: The following equation: IOUT = IEE11 + exp VDVTis valid for the output current IOUT produced by the second differential stage T12-T13 (block D), and if VD >> VT: IOUT = IEE exp (- VDVT) is obtained. Substituting equation (7) into equation (9): is obtained. As can be seen, the output current IOUT is given by the product of the constant bias current IEE of the second differential stage (block D), which is intrinsically temperature-stable, with the exponential function of a ratio between integrated resistors, which ratio is hence insensitive to temperature variations, of a logarithm of a pure number and of a ratio between substantially temperature-stable voltages. The current IOUT is therefore particularly suitable for exercising control of the gain of an amplifier in order to effect an extremely accurate system for automatic gain control (AGC), being insensitive to temperature variations. The necessary condition for forcing a current proportional to temperature and inversely proportional to the value of at least one integrated resistor across the first differential stage (block C), in order to permit the desired temperature compensation of the circuit of the invention, can also be satisfied using circuits different from the band-gap circuit (block B.G.). Fig. 4 shows a circuit alternatively suited to generating a current proportional to temperature and inversely proportional to the value of the temperature coefficient of the integrated resistors. The output current I₂ will in fact be given, to a good approximation, by the following equation: I₂ = KTq1RAHence, this, like other circuits, will be able to be used to generate the current I₂ to be forced across the first differential stage T3-T4 of the circuit of the invention, as will be evident to the expert. Moreover, it remains advantageous in integrated circuits where a band-gap circuit is already present, to add a transistor (T5) to drive the necessary current I₂ across the first differential stage. | An integrated circuit for the generation of a current proportional to the difference between a signal voltage (VAGC) and a reference voltage (VR) and independent of temperature, which comprises first means (B.G.) able to drive a bias current directly proportional to temperature and inversely proportional to the value of at least one integrated resistor across a first differential stage (C) having a first input and a second input and a first and a second output, which is able to carry out a voltage/voltage conversion, in accordance with an exponential law, of a differential input voltage (Vd) applied to said inputs; a current (IEE) generator able to drive a constant bias current essentially independent of temperature variations across a second differential stage (D) having a first input connected to said first output of said first differential stage and a second input connected to said second output of said first differential stage and which is able to carry out a voltage/current conversion, in accordance with an exponential law, in order to generate said output current (IOUT) across an output terminal, as a function of the differential voltage (VD) applied to said inputs; a differential input circuit (A) having a first input terminal to which is applied said signal voltage (VAGC) and a second input terminal to which is applied said reference voltage (VR), essentially independent of temperature, and formed by a pair of transistors (T1, T2) connected in a common-emitter configuration, respectively biased by means of two identical generators of current (I₁) respectively connected between a first supply node of the circuit and the emitters of said transistors and which are able to generate a current inversely proportional to the value of at least one integrated resistor, which emitters are interconnected across an integrated resistor (R₁), which transistors have identical, forward-biased diodes (D1, D2) as respective loads, respectively connected between the collectors of said transistors and a second virtual supply node of the circuit, the differential output voltage (Vd) across the collector nodes of said pair of transistors representing a current/voltage conversion, in accordance with a logarithmic law, of the respective currents (I₁ + x and I₁ - x) flowing through the transistors (T1, T2) of said pair and being applied to the inputs of said first differential stage (A), which currents represent a voltage/current conversion, in accordance with a linear/logarithmic law of the difference between said signal voltage (VAGC) and said reference voltage (VR). The integrated circuit as claimed in claim 1, wherein said first means able to generate a bias current directly proportional to temperature and inversely proportional to the value of at least one integrated resistor are a band-gap circuit and a transistor (T5) having a collector connected to a common emitter node of a pair of input transistors (T3, T4) of said first differential stage (C), an emitter substantially connected to a supply node and a base connected to the bases of a first pair of transistors (T6, T7) of said band-gap circuit which have their respective emmitters connected to said supply node. The integrated circuit as claimed in claim 1, wherein said two identical generators of current (I₁) for biasing the transistors (T1, T2) of said pair of transistors of the differential input circuit (A) generate a current with value equal to a ratio between a constant, temperature-stable voltage and an integrated resistor. An integrated circuit for the generation of a direct current (IOUT) for control of the gain of an amplifier comprising a circuit as claimed in Claim 1. The integrated circuit as claimed in claim 4, wherein said first means able to generate a bias current directly proportional to temperature and inversely proportional to the value of at least one integrated resistor are a band -gap circuit and a transistor (T5) having a collector connected to a common emitter node of a pair of input transistors (T3, T4) of said first differential stage, an emitter substantially connected to a supply node and a base connected to the bases of a first pair of transistors (T6, T7) of said band-gap circuit which have their respective emmitters connected to said supply node. The integrated circuit as claimed in claim 4, wherein said two identical generators of current (I₁) for biasing the transistors (T1, T2) of said pair of transistors of the differential input circuit (A) generate a current with value equal to a ratio between a constant, temperature-stable voltage and an integrated resistor. | SGS THOMSON MICROELECTRONICS; SGS-THOMSON MICROELECTRONICS S.R.L. | MOLONEY DAVID; SACCHI FABRIZIO; VAI GIANFRANCO; ZUFFADA MAURIZIO; MOLONEY, DAVID; SACCHI, FABRIZIO; VAI, GIANFRANCO; ZUFFADA, MAURIZIO |
EP-0490021-B1 | 490,021 | EP | B1 | EN | 19,941,123 | 1,992 | 20,100,220 | new | F16D65 | B22D19 | F16D65, B22D19 | F16D 65/10, R16D65:13B6, B22D 19/02, R16D200:260B2 | Composite brake drum for a motor vehicle and method for producing the same | The composite brake drum, particularly adapted for motor vehicle applications, includes a reinforcement assembly (30) embedded within the cylindrical portion (16) of the drum (10). The reinforcement assembly (30) is preferably made from steel wire stock and includes a plurality of circular loops (32) spaced axially within the brake drum cylindrical portion (16). Axially extending locator wires (34) are mechanically fastened to the reinforcing loops (32) and serve to locate the loops (32). End portions (38, 36) on the locator wire (34) contact only one of the mold halves (46) forming the mold cavity (50) and enable the device to be essentially self-locating without crossing the parting line (48) of the mold. By not crossing the parting line (48), the position of the loops (32) is maintained within acceptable tolerance limits from the finished friction surface (24) of the drum. The composite brake drum (10) is fabricated by pouring molten iron into the mold and then performing finish machining operations. | The invention relates to a composite brake drum as disclosed in claim 1. The invention further relates to a method for producing this brake drum. Brake drums used for motor vehicles such as heavy duty trucks are typically formed by casting grey iron and machining the casting in areas where precision dimensions and surfaces are required. Although iron brake drums perform satisfactorily, designers of braking systems are constantly striving for enhanced performance, lower cost, increased fatigue life and lighter weight. One particular shortcoming of conventional all-iron drums is their susceptibility to heat checking and crack formation which can ultimately lead to failure of the drum. As a means for providing an improved brake drum, composite structures are known in which steel is incorporated into an iron brake drum for reinforcement. For example, in accordance with U. S. Patent No. 2,316,029, a bell-shaped stamped sheet metal housing is provided having in iron inner portion centrifugally cast in place to form the friction surface of the drum. Although drums of this construction operate satisfactorily, the location of the steel reinforcing layer is not optimized since the higher bending stresses imposed on the brake drum by the brake shoes are very close to the inside cylindrical surfaces of the braking surface where the reinforcement of steel can be most advantageously used. Moreover, the process of manufacture of such a drum would require specialized machinery and processing steps. Another approach used in the past is to provide an externally applied reinforcing member such as a steel band as taught by U. S. Patent No. 3,841,448. This approach also requires specialized fabrication equipment and further does not optimally locate the steel reinforcing member. Moreover, the interface surfaces between the drum and reinforcement need to be precision machined and providing a good bond between the parts can be difficult. A steel wire ring is embedded within in iron brake drum structure according to U. S. Patent No. 2,111,709. Although this structure would likely provide improvements over in all-iron brake drum according to the prior art, the reinforcement provided by the single ring is positioned only to reinforce the open mouth of the brake drum. In addition, no means for positioning the reinforcing member during the molding process is disclosed by this patent. The large cross-sectional area of a single reinforcing ring could further lead to poor bonding between the iron and steel ring due to the heat sink imposed by the ring. The brake drum according to U.S. Patent No. 4,858,731, employs a cage-like reinforcement assembly made from steel wire which is cast in place to be substantially embedded within a grey iron brake drum. Locating wires are provided to position the reinforcement structure with respect to the mold cavity during casting. Since the steel material of the reinforcing assembly has a considerably higher modulus of elasticity than grey iron, the reinforcement increases the strength of the composite drum structure, thus decreasing mechanical deflection in response to loading. Although this brake drum makes improvements over previous drums, the locator wires of the reinforcement structure locate on both of the two mold halves when positioning the reinforcement structure. In this regard, the locator wires cross the parting line of the mold and present problems in terms of maintaining tolerances in the positioning of the reinforcement structure relative to the machined, loading or friction surface of the drum. Additionally, the interior ends of the locator wires were required to have precise diameters in that this end was required to contact both mold halves. Furthermore, this prior design tended to cause sand from the casting molds to be scraped free as the two mold halves are put together, leading to defects in the final product. The problem underlying the invention is to provide an improved composite brake drum in which the reinforcing structure is accurately positioned relative to the machined, loading or friction surface of the brake drum. Starting out from the composite brake drum of the generic kind this problem is solved in that the ends of the locator wires singly engage a common mold half used to cast said brake drum. Preferred embodiments of the composite brake drum of the present invention are described in claims 2 to 11. The composite brake drum of the invention can be produced by a method comprising the following steps: providing said first casting mold half having a surface defining a portion of a brake drum; providing said reinforcing structure; positioning said reinforcing structure in contact with said first mold half to locate said reinforcing structure relative to only said first mold half; providing said second casting mold half having a surface defining a portion of a brake drum; locating said second casting mold half relative to said first casting mold half to form a casting mold having a cavity exhibiting surfaces generally defining a portion of said brake drum and substantially encapsulating said reinforcing structure without said second casting mold half contacting said reinforcing structure ; casting said composite brake drum; and removing said composite brake drum from said casting mold. Advantageous kinds of performing this method are described in claims 13 to 19. The brake drum according to this invention employs a cage-like reinforcement assembly, preferably made from steel wire, which is cast in place to be substantially embedded within a grey iron brake drum. Specifically, the present invention offers an improvement in the locating and positioning of the reinforcement assembly relative to the machined, loading or braking surface of the drum. The locating means of the present invention accurately positions the reinforcement assembly with respect to one mold half during casting and therefore, neither crosses the parting line of the mold nor requires spanning the separation of the mold halves at the locating end. Thus, properly positioned, the reinforcement assembly eliminates the tolerance problems which lead to reduced drum life. The locating means also allows for easy reforming and fine tuning of the reinforcement assembly prior to mounting within the mold. This further assures accurate positioning of the reinforcement assembly. The present invention is additionally beneficial in that it allows green casting sand, which has been scraped or dislodged from the mold during positioning of the reinforcement assembly, to be cleared from the mold cavity before the mold is closed for actual casting. With the present reinforcement assembly contacting only one mold half, upon closing of the mold, additional casting sand will not be scraped from the second mold and the mold cavity will remain free from contaminants, upon closing of the mold. With the free or loose sand removed, the porosity of the casting is reduced and the strength of the drum proportionally increased. The reinforcement assembly also reduces the generation of surface checks and cracks which can propagate and ultimately cause mechanical failure of the brake drum. The increased strength of the composite further enables a reduction in the quantity of iron that is required to produce a brake drum of given strength, thus resulting in a lighter weight brake drum structure. The reinforcement assembly further results in the reinforcing sections being positioned close to the machined friction surfaces of the drum within tolerances required for the most advantageous structural efficiency. The axial aspect of the reinforcing assembly serves to reinforce the brake drum across the entire depth of the friction surface. Significantly, the composite brake drum according to this invention can be fabricated using conventional sand casting processes with minimal variations, thus saving the cost of retooling. Due to the fact that the metal reinforcing sections of this invention are distributed, relatively small diameter wires can be used which in turn enable the wires to be rapidly heated to temperatures near those of the molten iron being poured into the casting mold. Thus, good fusion between the iron and embedded steel reinforcement is promoted and casting cycle time is reduced. Additional benefits and advantages of the present invention will become apparent to those skilled in the art to which this invention relates from the subsequent description of the preferred embodiments and the appended claims, taken in conjunction with the accompanying drawings. Figure 1 is a perspective view of a composite motor vehicle brake drum structure constructed in accordance with this invention; Figure 2 is a cross-sectional view generally showing a portion of the brake drum as it is formed through casting processes; Figure 3 is a cross-sectional view generally taken along line 3-3 in Figure 1 showing the composite brake drum after finished machining operations; Figure 4 is a side view of a reinforcement assembly according to this invention; and Figure 5 is a cross-sectional view taken along line 5-5 of Figure 4 showing a reinforcement structure embodying the principles of the present invention. A composite brake drum in accordance with this invention is best shown in Figures 1 through 3 and is generally designated by reference number 10. Drum 10 has a mounting plate portion 12 configured to enable drum 10 to be mounted to a motor vehicle axle structure (not shown) for rotation about an axis of rotation 14. The mounting plate portion 12 merges into a cylindrical side portion 16, thus forming an free end 18 and a closed end 20. A so-called squeal band 22 is positioned adjacent the free end 18 and is a radially thickened portion of the brake drum 10. The inside cylindrical friction surface 24 of the drum 10 is engaged by expanding the brake shoes of a conventional drum type braking system. Figures 4 and 5 illustrate the configuration of a reinforcement assembly 30 in accordance with this invention. The reinforcement assembly 30 includes a plurality (six shown) of closed circular wire loops 32 made of steel wire stock. While individual loops 32 are employed in the present embodiment, a single continuously wrapped wire, looped in a general helical shape could also be used. Axially extending locator wires 34 are provided at circumferentially displaced positions as shown in Figure 4. The locator wires 34 are bonded or otherwise affixed to the loops 32, for example, by brazing, welding, soldering, adhering or by forming them integrally. Locator wires 34 have a radially outwardly turned ring 38 at one axial end and a generally offset contact portion 36 at the opposing end. The offset portion 36 is offset by a riser 40 which extends generally radially inward of the axial extending locator wire 34 toward the axis of rotation 14. A contact segment 41 of the offset portion 36 then continues in a generally axial direction until terminating in an outwardly directed toe or ski-nose 42. Figure 2 illustrates a process of casting a brake drum 10 according to this invention. As shown, a pair of sand cast molds halves 44 and 46 are provided which are separated at parting line 48 and define a mold cavity 50 whose surface forms the outer shape of the brake drum 10. As shown, the reinforcement assembly 30 is positioned within the mold cavity 50 such that offset portion 36, in particular the axial extension of the contact segment 41, is in contact with only the first or male mold half 46 and the ring 38 is fitted within a pocket 52 formed in the male mold half 46 for developing a portion of the squeal band 22. In previous brake drums, the position of the reinforcement assembly was engaged from both of the mold halves. This resulted in it being possible for the position of the reinforcement assembly to very along its length from the desired spacing distance, a distance measured from the friction surface, producing a non-uniform strength across the drum. The present invention overcomes this deficiency. The reinforcement structure 30 is positioned and mounted so as to reference the location and position of the loops 32 only with respect to the male mold half 46. Accordingly, the reinforcement structure 30 is fully positioned prior to the second or female mold half 44 being assembled or closed onto the male mold half 46. By limiting contact of the locating wires 34 to only the male mold half 46, the reinforcement assembly 30 does not traverse the parting line 48 as it is positioned within the mold cavity 50 (i.e. the locator wire 34 does not extend from the first mold half 46 thereafter contacting the second mold half 44). By not crossing the parting line 48, the positioning of the loops 32 is more accurately held relative to the braking surface. As seen in Figures 2 and 3, by referencing the reinforcement assembly 30 to only the male mold half 46, the loops 32 are more accurately positioned relative to the raw cast of the friction surface 24. As such, the friction surface 24 can be machined and finished while maintaining the loops 32 within the acceptable tolerances, thereby providing optimum and equally distributed strength within the composite drum 10. Since the locating wires 34 engage only the first mold half 46, it is possible to provide for a clean mold cavity 50, one absent of free or loose sand, for casting the drum 10. Whenever the reinforcement assembly 30 contacts the walls of the mold cavity, an amount of mold sand is scraped free at the place of contact. This occurs at each contact area. In the present invention, the reinforcement assembly 30 is positioned over the male mold half 46 and the assembly 30 contacts the male mold half 46 with the opposing ends 36, 38 of the locator wires 34. During the positioning of the reinforcement assembly 30, any amount of sand that would be scraped free is reduced by the elongated contacted segment 41 and ski-nose 42 of the offset portion 36 being connected to the remainder of the locator wire 34 by an axially and radially extending riser 40. As the reinforcement assembly is moved into its proper position, the contact segment 41 is able to slide along the mold half 46 with a rail or sledding action. In this manner, the terminal end or ski-nose 42 prohibits the contact segment 41 from being driven into the mold half 46. Prior to the positioning of the female mold half 44 over the male mold half 46, any free sand then present in the mold cavity 50 can be cleared to provide a clean mold cavity 50 for improved casting integrity. Typically, the sand is blown clear of the cavity 50. During casting, any free sand remaining within the mold cavity 50 will result in a contaminated casting having increased defects and reduced strength. Since the locator wires 34 will not contact the female mold half 44, the female mold half 44 may be brought into position without any additional sand being released into the cavity 50. Molten iron can now be poured into the mold cavity 50 to substantially embed the reinforcement assembly 30 while readily controlling the porosity to increase the strength of the drum 10. The offset shape of the offset contact portion 36 also allows for fine tuning or reforming of the reinforcement assembly 30 immediately prior to casting. By positioning the reinforcement assembly 30 over a solid duplicate of the mold, the orientation of the reinforcement assembly 30 can be readily checked and adjusted if necessary. Figure 3 is a cross-sectional view through the brake drum 10 after finish machining operations are completed. The phantom lines show the outline of the raw casting of the drum 10. As shown, the friction surface 24 is machined to form an accurate inside bore, this involves machining away the contact segment 41. Although iron is a superior material for forming the friction surface 24, the minute cross-sectional area of exposed steel caused by machining into the offset portion 36 does not produce adverse consequences along the interior surface. The rim surface 54 may be machined away causing a portion of the loop 38 to be removed. In previous designs, the locating ends were required to be embedded into and could disrupt the exterior surface of the cylindrical side portion 16. Since the exterior surface is subjected to extensive stress loading, it is desirable to eliminate the stress concentration induced by the presence of the machined locator ends along that surface. Additionally, the previously mentioned critical diameter is no longer necessary. The structural benefits provided by the composite brake drum 10, as compared with conventional cast brake drums, are manyfold. The ultimate tensile strength of grey iron is much less than that of steel and, accordingly, the steel of the reinforcement assembly 30 provides enhanced mechanical strength for the drum. The structure is also stiffer since the modulus of elasticity for steel is about twice that of grey iron, i.e. (20,7 to 10,3) x 10¹⁰ Pa or (30 to 15) x 10⁶ psi, respectively. Due to the increased modulus of elasticity of steel, the steel carries a disproportionately high fraction of the total load exerted on the brake drum as compared with its cross-sectional area. Accordingly, when steel is substituted for grey iron within the brake drum 10, the stress in the iron will be reduced and the stiffness of the composite will be enhanced as compared to a drum formed of iron alone. The benefits to be derived from such a composite structure include a reduction in the brake actuator travel of a vehicle and a higher tolerance to brake lining wear. In addition, the reduction in stress retards crack initiation and propagation. The configuration of the reinforcement assembly 30 in accordance with this invention further provides structural benefits in that the loops 32 are located close to the friction surface 24 and can readily be held within acceptable tolerances. Although stresses are applied onto a brake drum in numerous directions, a significant load is exerted on the cylindrical side portion 16 of the drum 10 in response to the radially outward travel of the brake shoes. Such a load places a tensile stress along the friction surface 24 and a tensile stress on the outer radial surface of the drum side portion 16. The steel making up the loops 32 has excellent tensile strength in extension and, with the positioning of the loops 32 in close proximity to the friction surface 24, such forces are far better restrained than in ordinary grey iron, which has a fairly low extension tensile strength. By positioning the loops 32 substantially equidistantly from the friction surface 24 along the surface's length, the strength of the composite brake drum 10 is uniformly increased across the friction surface 24. Disjunctions in strength could result in the drum 10 exhibiting an increased susceptibility to fatigue. | A composite brake drum (10) for a motor vehicle comprising : a mounting plate portion (12) for mounting said drum (10) to a motor vehicle axle structure for rotation about an axis of rotation (14); a cylindrical side portion (16) having a free end and an end joined to said mounting plate portion (12) and forming an inside cylindrical braking friction surface (24), said cylindrical side portion (16) having a reinforcing structure (30) substantially embedded therein and including at least two loops (32) extending circumferentially about said drum (10) and being coaxial with said axis of rotation (14), said loops (32) also being connected together and axially spaced from one another relative to said axis of rotation (14) by two or more axially extending locator wires (34) having ends (38, 36) for positioning said reinforcing structure (30) within said cylindrical side portion (16) during casting of the brake drum (10), at least one end (36) of said locator wires (34) extending axially beyond said loops (32), characterized in that said ends (38, 36) of said locator wires (34) singly engage a common mold half (46) used to cast said brake drum (10). A composite brake drum as set forth in claim 1 wherein said axially extending end includes a generally concave contact portion (36) for contacting a length of said common mold half (46), said concave contact portion (36) being open in a radially outward direction from said axis of rotation (14). A composite brake drum as set forth in claim 2 wherein said contact portion (36) includes a riser (40) extending radially inward from said loops (32) toward said axis of rotation (14), said riser (40) being connected to a generally axially extending contact segment (41) for contact with said inside cylindrical braking friction surface (24). A composite brake drum as set forth in claim 3 wherein said contacting segment (41) terminates in a radially outwardly extending end (42). A composite brake drum as set forth in one of the claims 1 to 4 wherein one end of said locator wires (34) forms a ring (38) contacting said inside cylindrical braking friction surface (24) and positioning said reinforcing structure (30) in said cylindrical side portion (16). A composite brake drum as set forth in one of the claims 1 to 5 wherein said reinforcing structure (30) includes three locator wires (34) equidistantly spaced about said loops (32). A composite brake drum as set forth in one of the claims 1 to 6 wherein said loops (32) are axially spaced apart such that one of said loops (32) is adjacent said free end (18) and another of said loops (32) is adjacent said end joined to said mounting plate portion (12). A composite brake drum as set forth in claim 7 wherein said reinforcing structure (30) includes six loops (32). A composite brake drum as set forth in one of the claims 1 to 8 wherein said loops (32) are formed steel wire. A composite brake drum as set forth in one of the claims 1 to 9 wherein said locator wires (34) are welded to said loops (32). A composite brake drum as set forth in one of the claims 1 to 10 wherein the common mold half contacted by said ends (38,36) of said locator wires (34) is a male mold half. A method of casting the composite brake drum according to one of the preceding claims, comprising the steps of: providing said first casting mold half (46) having a surface defining a portion of a brake drum (10); providing said reinforcing structure (30); positioning said reinforcing structure (30) in contact with said first mold half (46) to locate said reinforcing structure (30) relative to only said first mold half (46); providing said second casting mold half (44) having a surface defining a portion of a brake drum (10); locating said second casting mold half (44) relative to said first casting mold half (46) to form a casting mold having a cavity (50) exhibiting surfaces generally defining a portion of said brake drum (10) and substantially encapsulating said reinforcing structure (30) without said second casting mold half (44) contacting said reinforcing structure (30); casting said composite brake drum (10) ; and removing said composite brake drum (10) from said casting mold. The method as set forth in claim 12 further comprising the step of removing loose particles from said first mold surface to clean said first mold surface. The method as set forth in claim 13 wherein said cleaning is performed after positioning said reinforcing structure (30) in contact with said first mold half (46). The method as set forth in claim 13 wherein said cleaning is performed by blowing a blowing medium over said first mold surface. The method as set forth in one of the claims 12 to 15 wherein said first casting mold half (46) is a male mold half. The method as set forth in one of the claims 12 to 16 wherein said second casting mold half (44) is located onto said first casting mold half (46) by movement in a substantially horizontal direction. The method as set forth in one of the claims 12 to 17 wherein said composite brake drum (10) is cast with said axis of rotation (14) being oriented generally horizontally. The method as set forth in claim 18 wherein said reinforcing structure (30) is positioned in contact with said first mold half (46) so that one of said locator wires (34) is oriented substantially vertically downward of said axis of rotation (14). | BUDD CO; THE BUDD COMPANY | RAITZER DONALD ALBERT; TWISDOM RAYMOND JOSEPH; RAITZER, DONALD ALBERT; TWISDOM, RAYMOND JOSEPH |
EP-0490024-B1 | 490,024 | EP | B1 | EN | 19,950,517 | 1,992 | 20,100,220 | new | H02P5 | null | H02P21 | H02P 21/14P, H02P 21/08S | Induction motor vector control | An induction motor vector control apparatus employing a rotating Cartesian coordinate system (d,q) having a d-axis held in coincidence with a secondary flux of the induction motor. Another rotating Cartesian coordinate system (γ, δ) having a γ-axis held in coincidence with the induction motor primary current to detects a δ-axis induction motor primary voltage change caused by a change in the induction motor secondary resistance. The δ-axis primary voltage change contains no component related to a primary resistance change and it is used to compensate the secondary resistance for its change. | BACKGROUND OF THE INVENTIONThis invention relates to an apparatus for controlling an adjustable speed electric motor and, more particularly, to an apparatus for vector control of an induction motor. Electric power converters or inverters have been employed for the application of adjustable speed drives using alternating current motors. A typical converter includes a direct current (DC) rectifier for rectifying three-phase AC input voltage and for supplying the resulting direct current (DC) bus potential to an inverter. The inverter comprises a plurality of pairs of series-connected switching elements to generate an adjustable frequency output. In many applications, such a frequency adjustment is effected through a control circuit which employs a pulse width modulation (PWM) control technique in producing variable frequency gating pulses to periodically switch the respective switching elements so as to operate the motor at a variable speed. The motor can be propelled (motoring mode) or retarded (braking mode) as desired by appropriately varying the frequency and the amplitude of the excitation that the inverter applies to the motor (see for example the 3rd European Conference on Power electronics and applications Vol. 3,12 October 1989, pages 1079-1085). The actual motor speed is sensed and compared with a commanded motor speed. A speed error signal, which depends on the difference between the actual and desired values of motor speed, is derived and applied to a proportional plus integral control circuit which converts it into a torque command signal. The control circuit responds to the torque command signal by controlling the operation of the inverter so as to vary, as a function of the torque command signal, the amplitude of the voltages supplied from the inverter to the motor. In order to provide more accurate motor control and linear motor torque control for variations in commanded torque, vector control has been proposed and employed. Such vector control utilizes a secondary flux rotational speed together with the torque command signal to control the momentary values of the frequency and amplitude of the stator current of the motor. It has been proposed to compensate for the influence of changes in the primary and secondary resistances of the induction motor on the vector control. The compensation has been made on an assumption that the excitation current is constant. However, this assumption is not satisfied when the secondary flux changes. A secondary resistance compensation is disclosed in JP-A-61147788. SUMMARY OF THE INVENTIONTherefore, a main object of the invention is to provide an improved vector control apparatus which can provide more accurate motor control. There is provided, in accordance with a first embodiment of the invention, an apparatus employing a rotating Cartesian coordinate system (d, q) having a d-axis and q-axis, the d-axis being held in coincidence with a secondary flux of the induction motor, for vector control of an adjustable-speed induction motor. The apparatus comprises means for applying a primary current and voltage to drive the induction motor, means sensitive to an induction motor angular velocity for producing an induction motor angular velocity value ωr, means for producing a d-axis secondary flux command value λ2d*, means for calculating a d-axis primary current command value i1d* as a function of the d-axis secondary flux command value λ2d* and a secondary time constant command value L2*/R2*, means for producing a q-axis primary current command value i1q*, means employing a rotating Cartesian coordinate system (γ, δ) having a γ-axis and δ-axis, the γ-axis being held in coincidence with the primary current I1, for calculating a γ-axis primary current command value i1γ* and a phase angle ψ of the γ-axis with respect to the d-axis as a function of the primary current command values i1d* and i1q*, means for calculating the γ- and δ-axis primary voltage command values v1γ* and v1δ* as a function of the γ-axis primary current command value i1γ*, the phase angle ψ, the d-axis secondary flux command value λ2d*, and a primary voltage angular frequency ω0, means for sensing the primary current and converting the sensed primary current into γ- and δ-axis primary current values i1γ and i1δ, means for calculating a γ-axis primary voltage change Δv1γ as a function of the γ-axis primary current value i1γ and the γ-axis primary current command value i1γ*, means for calculating a δ-axis primary voltage change Δv1δ as a function of the δ-axis primary current value i1δ and a δ-axis primary current command value i1δ*, means for adding the γ-axis primary voltage change Δv1γ to the γ-axis primary voltage command value v1γ* to produce a γ-axis primary voltage command signal v1γ, means for adding the δ-axis primary voltage change Δv1δ to the δ-axis primary voltage command value v1δ* to produce a δ-axis primary voltage command signal v1δ, means for calculating a secondary resistance change as a function of the d-axis primary current command value i1d*, the q-axis primary current command value i1q*, the γ-axis primary current command value i1γ*, the d-axis secondary flux command value λ2d*, the primary voltage angular frequency ω0 and the δ-axis primary voltage change Δv1δ, means for correcting the secondary time constant command value L2*/R2* based upon the secondary resistance change, means for calculating a slip frequency ωs as a function of the q-axis primary current command value i1q*, the d-axis secondary flux command value λ2d*, and the corrected secondary time constant command value, means for adding the slip frequency ωs to the induction motor angular velocity value ωr to produce the primary voltage angular frequency ω0, and means for controlling the motor driving means to adjust the primary voltage based upon the primary voltage command signals v1γ and v1δ, and the primary voltage angular frequency ω0. In a second embodiment of the invention, the induction motor vector control apparatus of the first embodiment further comprises means for subtracting the δ-axis primary current i1δ from the δ-axis primary current command value i1δ* to produce a difference (i1δ* - i1δ), means for multiplying the difference (i1δ* - i1δ) by a leakage inductance Lσ to produce a multiplied value (i1δ* - i1δ)·Lσ, means for integrating the difference (i1δ* - i1δ) to produce an integrated value Δv1δI, means for adding the multiplied value to the integrated value to produce a δ-axis primary voltage change Δv1δ, and wherein the δ-axis primary voltage change used by the means for calculating a secondary resistance change is the integral value Δv1δI. In a third embodiment of the invention, the induction motor vector control apparatus comprises means for applying a primary current and voltage to drive the induction motor, means sensitive to an induction motor angular velocity for producing an induction motor angular velocity value ωr, means for producing a d-axis secondary flux command value λ2d*, means for calculating a d-axis primary current command value i1d* as a function of the d-axis secondary flux command value λ2d*, and a secondary time constant command value L2*/R2*, means for producing a q-axis primary current command value i1q*, means employing a rotating Cartesian coordinate system (γ, δ) having a γ-axis and δ-axis, the γ-axis being held in coincidence with the primary current I1, for calculating a γ-axis primary current command value i1γ* and a phase angle ψ of the γ-axis with respect to the d-axis as a function of the primary current command values i1d* and i1q*, means for calculating the γ- and δ-axis primary voltage command values v1γ* and v1δ* as a function of the γ-axis primary current command value i1γ*, the phase angle ψ, the d-axis secondary flux command value λ2d*, and a primary voltage angular frequency ω0, means for sensing the primary current and converting the sensed primary current into γ- and δ-axis primary current values i1γ and i1δ, means for calculating a γ-axis primary voltage change Δv1γ as a function of the γ-axis primary current value i1γ and the γ-axis primary current command value i1γ*, means for calculating a δ-axis primary voltage change Δv1δ as a function of the δ-axis primary current value i1δ and a δ-axis primary current command value i1δ*, means for adding the γ-axis primary voltage change Δv1γ to the γ-axis primary voltage command value v1γ* to produce a γ-axis primary voltage command signal v1γ, means for adding the δ-axis primary voltage change Δv1δ to the δ-axis primary voltage command value v1δ* to produce a δ-axis primary voltage command signal v1δ, means for calculating a slip frequency command value ωs* as a function of the q-axis primary current command value i1q* and the d-axis secondary flux command value λ2d*, means for calculating a difference of the δ-axis primary voltage change Δv1δ from a δ-axis primary voltage change command value, means for calculating a slip frequency change Δωs as a function of the calculated difference, means for adding the slip frequency change Δωs to the slip frequency command value ωs* to produce a slip frequency ωs, means for adding the slip frequency ωs to the induction motor angular velocity value ωr to produce the primary voltage angular frequency ω0, and means for controlling the motor driving means to adjust the primary voltage based upon the primary voltage command signals v1γ and v1δ, and the primary voltage angular frequency ω0. In a fourth embodiment of the invention, the induction motor vector control apparatus of the third embodiment further comprises means for subtracting the δ-axis primary current i1δ from the δ-axis primary current command value i1δ* to produce a difference (i1δ* - i1δ), means for multiplying the difference (i1δ* - i1δ) by a leakage inductance Lσ to produce a multiplied value (i1δ* - i1δ)·Lσ, means for integrating the difference (i1δ* - i1δ) to produce an integrated value Δv1δI, means for adding the multiplied value to the integrated value to produce a δ-axis primary voltage change Δv1δ, means for calculating a secondary resistance change K as a function of the calculated difference, means for multiplying the calculated difference by the slip frequency command value ωs* to produce a slip frequency change Δωs. BRIEF DESCRIPTION OF THE DRAWINGSThe invention will be described in greater detail by reference to the following description taken in connection with the accompanying drawings, in which like reference numerals identify like elements in the several figures and in which: Fig. 1 is a schematic diagram showing a prior art induction motor vector control apparatus; Fig. 2 is a diagram showing the relationship between the primary and secondary currents and voltages expressed in coordinate systems (d, q) and (γ, δ) ; Fig. 3 is a diagram showing the relationships between the primary voltage changes expressed in the coordinate systems (d, q) and (γ, δ); Fig. 4 is a circuit diagram showing an equivalent circuit for an induction motor; Fig. 5 is a diagram showing the vectors of the currents produced in the equivalent circuit of Fig. 4; Fig. 6 is a diagram showing the vectors of the voltages produced in an equivalent circuit for an idling induction motor; Fig. 7 is a schematic diagram showing a first embodiment of an induction motor vector control apparatus made in accordance with the invention; Fig. 8 is a schematic diagram showing a second embodiment of the induction motor vector control apparatus of the invention; Fig. 9 is a schematic diagram showing a modified form of the second embodiment of the invention; Fig. 10 is a schematic diagram showing a third embodiment of the induction motor vector control apparatus of the invention; Fig. 11 is a schematic diagram showing a modified form of the third embodiment of the invention; Fig. 12 is a schematic diagram showing a fourth embodiment of the induction motor vector control apparatus of the invention; Fig. 13 is a schematic diagram showing a modified form of the fourth embodiment of the invention; Fig. 14 is a schematic diagram showing another modified form of the fourth embodiment of the invention; Fig. 15 is a flow diagram showing the programming of the digital computer used in the induction motor vector control apparatus of the invention; and Fig. 16 is a flow diagram showing the programming of the digital computer used in the induction motor vector control apparatus of the invention. DETAILED DESCRIPTION OF THE INVENTIONPrior to the description of the preferred embodiments of the present invention, the prior art vector control apparatus of Fig. 1 is briefly described. The principles on which the conventional vector control apparatus is based are as follows: An induction motor voltage equation expressed in a two-dimensional Cartesian coordinate system (d, q) rotating at the same angular velocity as the angular velocity of the primary voltage to the induction motor is given as where ωs = ωo - ωr, Lσ = (L1 · L2 - M²)/L2, v1d is the primary voltage in the d-axis, v1q is the primary voltage in the q-axis, i1d is the primary current in the d-axis, i1q is the primary current in the q-axis, λ2d is the secondary flux in the d-axis, λ2q is the secondary flux in the q-axis, P is the differentiating operator, R1 is the primary resistance, R2 is the secondary resistance, L1 is the primary inductance, L2 is the secondary inductance, M is the excitation inductance, Lσ is the equivalent leakage inductance, ωo is the primary voltage angular frequency, ωr is the rotor angular frequency, and ωs is the slip frequency. Assuming now that the d-axis is held in coincidence with the direction of the secondary flux, the q-axis secondary flux λ2q is zero, the d-axis secondary flux λ2d is a constant value 2, the d-axis secondary current i2d is zero, and the q-axis secondary current i2q is equal to the secondary current i2. It is, therefore, possible to control the induction motor like DC motors. The d- and q-axis secondary flux λ2d and λ2q are λ2d = M · i1d + L2 · i2d λ2q = M · i1q + L2 · i2q Since i2d = 0 and i2q = 0 under the vector control, the d-axis secondary flux is equal to M·i1d and the q-axis primary current i1q is equal to - L2/M·i2q. Thus, the q-axis primary current i1q is proportional to the torque current. From the fourth row of Equation (1), the following equation is derived: - R2L2 · M · i1q + ωs · λ2d = 0 This equation is solved for the slip frequency as ωs = R2L2 · M · i1qλ2d = R2L2 · M · i1qM · i1d = R2L2 · i1qi1dThus, the vector control is made by getting the d-axis primary current i1d at λ2d/M and the slip frequency ωs at a value calculated from Equation (5). As can be seen from Equation (5), the secondary resistance R2 used in calculating the slip frequency ωs changes with changes in ambient and rotor temperatures. It is, therefore, required to estimate the secondary resistance change based upon inverter output voltage and to correct the slip frequency command value ωs* based upon the secondary resistance change estimated from the inverter voltage. If the secondary resistance changes are ignored, the vector control is degraded for torque control accuracy and torque response time. If the inverter output voltage is used as it is to estimate the secondary resistance change, however, a component related to the primary resistance change will be introduced into the estimated secondary resistance change. For this reason, it is desirable to estimate the secondary resistance change based upon a signal which is independent from the primary resistance change. The vector control apparatus is arranged to control excitation currents iu, iv and iw that an inverter 10 applies to an induction motor IM by utilizing motor-flux and motor-torque command signals i1d* and i1q*. The induction motor IM has three-phase stator windings which are energized by the output of the inverter 10 and a rotor coupled to drive a mechanical load. The inverter 10 includes a plurality of parallel pairs of series-connected switching element arranged and controlled to convert DC input power into AC output power having adjustable frequency and voltage magnitude. The inverter 10 is controlled by a pulse-width-modulation (PWM) circuit 11 which includes a PWM waveform generator, a triangle waveform generator and a gating circuit. The PWM waveform generator receives a triangle wave signal from the triangle waveform generator and controls the gating circuit to produce gating pulses so as to periodically switch the respective switching elements of the inverter in a predetermined sequence and at a desired frequency. The vector control apparatus includes a rotor angular velocity sensor 12 connected to a pulse pickup transducer PP. This transducer is associated with the rotor of the induction motor IM for producing a series of electric pulses of a repetition rate directly proportional to the speed of rotation of the rotor. The rotor angular velocity sensor 12 receives the electric pulses and produces an actual rotor angular velocity signal ωr indicative of the sensed angular velocity ωr of the rotor. The actual rotor angular velocity signal ωr is fed to a secondary flux command generator 13 which receives a command signal λ2d*/M*. The secondary flux command generator 13 produces a command signal i1d* which remains at a value λ2d*/M* when the actual rotor angular velocity ωr is less than a predetermined value and decreases as the actual rotor angular velocity ωr increases when the actual rotor angular velocity ωr exceeds the predetermined value. The secondary flux command signal i1d* is fed from the secondary flux command generator 13 to a calculation circuit 16. The actual rotor angular velocity signal ωr is also fed to a summing circuit 14 which subtracts it from a rotor angular velocity command signal ωr* to provide an error output signal. In order to enhance the induction motor control for stability and response time, a proportional plus integral operation is provided on this error signal at a proportional plus integral circuit 15 to produce a torque command signal i1q*. The torque command signal i1q* is applied to the calculation circuit 16. The calculation circuit 16 utilizes the command signals i1d* and i1q* to calculate command values v1d* and v1q* for the d- and q-axis components of the primary voltage applied to the induction motor IM. The conventional vector control apparatus also includes a coordinate converter 17 which senses two excitation currents iu and iv to the induction motor IM and converts them into d- and q-axis primary current signals i1d and i1q. The d-axis primary current signal i1d is applied to a summing circuit 18 which subtracts it from the secondary flux command signal i1d* fed thereto from the secondary flux command generator 13 to provide an error signal. A proportional plus integral operation is provided on this error signal at a proportional plus integral circuit 19 to produce a signal Δv1d. The signal Δv1d is then applied to a summing circuit 22 which adds it to the command signal v1d* to correct the command signal v1d*. The corrected signal vid is applied to a coordinate transformer 24. Similarly, the q-axis primary current signal i1q is applied to a summing circuit 20 which subtracts it from the torque command signal i1q* fed thereto from the proportional plus integral circuit 15 to provide an error signal. A proportional plus integral operation is provided on this error signal in a proportional plus integral circuit 20 to produce a signal Δv1q. The signal Δv1q is applied to a summing circuit 23 which adds it to the signal v1q* to correct the command signal v1q*. The corrected signal v1q is applied to the coordinate transformer 24. The signals Δv1d and Δv1q contain components related to changes in the primary and secondary resistances R1 and R2. Fig. 2 is a diagram showing the relationship between the primary and secondary currents and voltages expressed in coordinate systems (d, q) and (γ, δ), and Fig. 3 is a diagram showing the relationship between the primary voltage changes expressed in the coordinate systems (d, q) and (γ, δ). In these figures, the character V indicates the primary voltage, the character E is the secondary voltage, the character Δv1 is the primary voltage change, the character Δv1γ is the γ-axis primary voltage change, the character Δv1δ is the δ-axis primary voltage change, the character ψ is the phase angle of the γ-axis with respect to the d-axis, the character I0 is the excitation current, and the character I2 is the torque current. The δ-axis primary voltage change Δv1δ is given as Δv1δ = -Δv1d · sinψ + Δv1q · cosψ where sinψ = I2/I1 = i1q/i1γ and cosψ = I0/I1 = i1d/i1γ. The d- and q-axis primary voltage changes contains components related to first and second resistance changes. In the conventional apparatus, however. the vector control is made on an assumption that i1d = λ2d/M, that is, the d-axis excitation current i1d is constant without regard to secondary flux control. For this reason, the slip frequency cannot be calculated with high accuracy. The relationship between the d-axis secondary flux λ2d and the d-axis primary current ild may be derived from the third row of Equation (1) as - R2L2 · M · i1d + (R2L2 + P) · λ2d - ωs · λ2q = 0 i1d = L2R2 · λ2dM · (R2L2 + P) = λ2dM · (1 + L2R2 · P) As can be seen from Equation (8), the d-axis primary current i1d should be controlled in a fashion of time advance of first order with respect to changes in the d-axis secondary flux λ2d. In other words, the condition λ2d = M·i1d cannot be established when the secondary flux command λ2d* changes. The principles of the invention will be described with reference to Figs. 4 and 5. Fig. 4 shows an asymmetrical T-I type equivalent circuit for an induction motor. Fig. 5 is a diagram showing the vectors of the currents produced in the equivalent circuit of Fig. 4. Assuming now that the γ-axis is held in coincidence with the direction of the primary current I1, the γ-axis primary current i1γ is equal to the primary current I1 and the δ-axis primary current i1δ is zero. The induction motor voltage equation expressed in the two-dimensional Cartesian coordinate system (γ, δ) rotating at the same angular velocity as the angular velocity of the primary voltage to the induction motor IM is given as From the third and fourth rows of Equation (9), the following equations are derived: - R2L2 · M · i1γ + (R2L2 + P) · λ2γ - ωs · λ2δ = 0 ωs · λ2γ + (R2L2 + P) · λ2δ = 0 From Equation (11), the following equation is derived: R2/L2 + P = - λ2γ · ωs/λ2δ Substituting Equation (12) into Equation (10) gives the following equation: - R2L2 · M · i1γ - λ2γ²λ2δ · ωs - λ2δ · ωs = 0 - R2L2 · M · i1γ - (λ2γ² + λ2δ²λ2δ) · ωs = 0 Thus, ωs = - λ2δλ2γ² + λ2δ² · R2L2 · M · i1γ The d- and q-axis secondary fluxes λ2γ and λ2δ are λ2γ = λ2d cosψ λ2δ = - λ2dsinψ λ2γ² + λ2δ² = λ2d² Substituting Equations (14), (15) and (16) into Equation (13) gives the following equation: ωs = R2L2 · M · i1γ · sinψλ2d = R2L2 · M · i1qM · i1d = R2L2 · i1qi1dIt can be seen from Equation (17) that the slip frequency ωs can be calculated from the same equation as Equation (5) used to calculate the slip frequency in the conventional vector control apparatus if the γ- and δ-axis primary currents i1γ and i1δ are controlled to establish conditions of i1γ = I1 and i1δ = 0 with the γ-axis being held in coincidence with the direction of the primary current I1. If the vector control is made with regard to secondary flux control, that is, the d-axis secondary flux λ2d is not equal to M·i1d, the slip frequency ωs is ωs = R2L2 · i1q(λ2d/M) Considerations are made to the voltage commands v1γ* and v1δ*. Since the vector control is made on the coordinate system (γ, δ) with i1γ* = I1 and i1δ* = 0, the following equation can be derived from Equation (9): Equation (19) may be modified to remove the terms affixed to the differentiating operator P. When vector control conditions are satisfied, the following equations are given λ2γ* = λ2d* · cosψ =M · λ2d*M · cosψ λ2δ* = - λ2d* · sinψ = - M · λ2d*M · sinψ Thus, multiplying out (20) v1γ* = R1 · i1γ* + M²L2 · ω₀ · λ2d*M · sinψ v1δ* = Lσ · ω₀ · i1γ* + M²L2 · ω₀ · λ2d*M · cosψ The term P·i1γ affixed to Lσ in Equation (19) cannot be ignored when a rapid change occurs in the torque command i1q* and/or when the excitation current command i1d* changes. With regard to the term P·i1γ, the voltage commands v1γ* and v1δ* are v1γ* = R1 · i1γ* + Lσ · P · i1γ* + M²L2 · ω₀ · λ2d*M · sinψ = R1(1 + LσR1 · P)i1γ* + M²L2 · ω₀ · λ2d*M · sinψ v1δ* = Lσ · ω₀ · i1γ* + M²L2 · ω₀ · λ2d*M cosψ Considerations are made to a secondary flux change with a secondary resistance change. The following equations are derived from the third and fourth rows of Equation (9): - R2L2 · M · i1γ + (R2L2 + P) · λ2γ - ωs · λ2δ = 0 ωs · λ2γ + (R2L2 + P) · λ2δ = 0 Multiplying Equations (27) and (28) by L2/R2 gives -M · i1γ + (1 + L2R2 · P) · λ2γ - L2R2 · ωs · λ2δ = 0 L2R2 · ωs · λ2γ + (1 + L2R2 · P) · λ2δ = 0 Multiplying Equation (29) by (1 + L2 · P/R2) gives -M · (1 + L2R2 · P) · i1γ + (1 + L2R2 · P)² · λ2γ - L2R2 · ωs · (1 + L2R2 · P) · λ2δ = 0 Multiplying Equation (30) by L2·ωs/R2 gives (L2R2 · ωs)² · λ2γ + L2R2 · ωs · (1 + L2R2 · P) · λ2δ = 0 Adding Equation (31) to Equation (32) gives λ2γ = M·(1 + L2R2·P)·i1γ(1 + L2R2·P)² + (L2R2·ωs)²Multiplying Equation (29) by L2 · ωs/R2 gives -M · L2R2 · ωs · i1γ + L2R2 · ωs · (1 + L2R2 · P) · λ2γ - (L2R2 · ωs)² · λ2δ = 0 Multiplying Equation (30) by (1 + L2 · P/R2) gives L2R2 · ωs · (1 + L2R2 · P) · λ2γ + (1 + L2R2 P)² · λ2δ = 0 Subtracting Equation (34) from Equation (35) gives λ2δ = - M · L2R2 · ωs · i1γ(1 + L2R2 · P)² + (L2R2 · ωs)²It is now assumed that the currents are controlled to respective command values and thus i1γ* = i1γ, i1δ* = i1δ = 0, i1d* = i1d, and i1q* = i1q. Since R2 = (1 + K)·R2* where K is the secondary resistance change, the term L2·ωs/R2 used in Equations (33) and (36) may be expressed as the following, with the use of (18) L2R2 · ωs = L2*(1 + K) · R2* · R2*L2* · i1q*λ2d*M* = 1(1 + K) · i1q*λ2d*M*Since the excitation current is controlled as shown in Equation (8), the following equation is obtained: i1d* = λ2d*M* · (1 + L2*R2* · P) Assuming now that the secondary time constant L2/R2 of the term (1 + L2·P/R2) is equal to L2*/R2*, that is, the secondary resistance R2 is unchanged in a short time, the following equation is given: 1 + L2R2 · P = i1d*λ2d*M*Substituting Equations (39) and (37) into Equations (33) and (36) gives λ2γ = λ2d* · (1 + K)² · i1d* · i1γ*(1 + k)² · i1d*² + i1q*²λ2δ = -λ2d* · (1 + K) · i1q* · i1γ*(1 + k)² · i1d*² + i1q*²Thus, the secondary flux command values are given as λ2γ* = λ2d* · cosψ= λ2d* · i1d*i1γ*λ2δ* = -λ2d* · sinψ = -λ2d* · i1q*i1γ*ψ = tan⁻¹ i1q*i1d*Using Equations (40) and (42), the following equation is given: Δλ2γ = λ2γ - λ2γ* = λ2γ* · {(1 + K)² · i1γ*²(1 - k)² · i1d*² + i1q*² - 1} Using Equations (41) and (43), the following equation is given Δλ2δ = λ2δ - λ2δ* = λ2δ* · {(1 + K) · i1γ*²(1 + k)² · i1d*² + i1q*² - 1} When the secondary flux changes, the primary current is from Equation (20) v1γ = R1 · i1γ* - M*L2* · ω₀(λ2δ* + Δλ2δ) v1δ = Lσ* · ω₀ · i1γ* + M*L2* · ω₀(λ2γ* + Δλ2γ) Since the primary voltage command value is expressed by Equations (23) and (24), the voltage changes are derived from Equations (23), (24), (47) and (48) along with Equations (45) and (46). First (47) and (23) Δv1γ = v1γ - v1γ* = - M*L2* · ω₀ · Δλ2δ substitute (46) = - M*L2* · ω₀ · λ2δ* {(1 + K) · i1γ*²(1 + k)² · i1d*² + i1q*² - 1} = M*²L2* · ω₀ · λ2d*M* · i1q*i1γ* {(1 + K)² · i1γ*²(1 + k)² · i1d*² + i1q*² - 1} First (48) and (24) Δv1δ = v1δ - v1δ* = + M*L2* · ω₀ · Δλ2γ substitute (45) = + M*L2* · ω₀ · λ2γ* {(1 + K)² · i1γ*²(1 + k)² · i1d*² + i1q*² - 1} = M*²L2* · ω₀ · λ2d*M* · i1d*i1γ* {(1 + K)² · i1γ*²(1 + k)² · i1d*² + i1q*² - 1} where it has been assumed that M/L2 is equal to M*/L2*, that is the excitation inductance is unchanged in a short time. Since the γ-axis primary voltage v1γ contains a component related to the term R1·i1γ*, it contains a component related to a voltage change caused by a change in the primary resistance R1. With regard to a change in the primary resistance R1, Equation (47) becomes, using R1 = (1+A1)·R1* v1γ = (1 + A1)R1* · i1γ* - ML2 · ω₀(λ2δ* + Δλ2δ) = R1* · i1γ* - ML2ω₀ · λ2δ* + λ1 · R1* i1γ* - ML2 · ω₀ · Δλ2δ Thus, Δv1γ = v1γ - v1γ* = A1 · R1* · i1γ* + M2L2* · ω₀ · λ2d*M*i1q*i1γ* {(1 + K) · i1γ*²(1 + k)² · i1d*² + i1q*² - 1} where A1 is a primary resistance change. Although the term Δv1, which contains a component related to a change in the primary resistance R1, is not suitable for use in correcting for a change in the secondary resistance R2, the δ-axis primary voltage change Δv1δ contains no component related to the primary resistance R1 and it may be considered as a voltage change component caused by a secondary resistance change. It is, therefore, possible to eliminate the influence of the primary resistance R1 by detecting the change Δv1δ of the δ-axis primary voltage v1δ and using the detected change Δv1δ to correct the secondary resistance change. As a result, the secondary resistance correction can be free from the influence of the primary resistance R1 which changes with changes in temperature. Normally, the influence of voltage drops caused by the primary resistance R1 increases at slow induction motor speeds. Since the δ-axis primary voltage v1δ contains no component related to a voltage drop caused by the primary resistance R1, however, it is possible to provide an accurate secondary resistance correction at slow induction motor speeds. In addition, it is possible to estimate the primary resistance R1 by detecting the γ-axis primary voltage change Δv1γ which is a voltage component caused only by a change in the primary resistance R1 when the secondary resistance correction is made based upon the δ-axis primary voltage change Δv1δ The secondary resistance change K is given by modifying Equation (50) as 1 + K = M*²L2* · ω₀ · λ2d*M* · i1d* · i1q*² + i1γ* · i1q*² · Δv1δM*²L2* · ω₀ · λ2d*M* · i1d* · i1q*² - i1γ* · i1d*² · Δv1δThus, if the δ-primary voltage change Δv1δ is detected, the secondary resistance change K can be calculated from Equation (53). Considerations are made to identification of the primary resistance R1 and the excitation inductance M during induction motor idling operation. The ratio of the excitation current to the torque current changes to change the primary voltage with changes in the excitation inductance M. Since the primary voltage changes with changes in the secondary resistance R2, it is impossible to distinguish a primary voltage change caused by an excitation inductance change from a primary voltage change caused by a secondary resistance change. Since the torque current i1q is zero during induction motor idling operation, however, the primary voltage change is free from the influence of the secondary resistance change. It is, therefore, possible to make an excitation inductance correction using the primary voltage change detected during induction motor idling operation. Fig. 6 is a diagram showing the vectors of the voltage produced in a T-I type equivalent circuit for an idling induction motor. Since the torque current i1q is zero during induction motor idling operation, the d-axis and q-axis of the coordinate system (d,q) are in coincidence with the -axis and δ-axis of the coordinate system (γ,δ), respectively. Thus, considerations are made to the coordinate system (d, q). During induction motor idling operation where the q-axis primary current i1q is zero, the primary current is derived from Equation (19) with the term P being ignored as v1d = R1 · i1d viq = Lσ · ω₀ · i1d + M²L2 · ω₀ · λ2d*MIt is now assumed that i1d* = i1d since the d-axis primary current i1d is controlled to the command value i1d*, AM is the excitation inductance change, and the change in the equivalent leakage inductance Lσ is small and can be ignored. The command voltage value during induction motor idling operation is expressed as v1d* = R1* · i1d* viq* = Lσ · *ω₀ · i1d* + M*²L2* · ω₀ · λ2d*M*Using the primary resistance change A1 and the excitation inductance change AM. the primary voltage can be expressed as v1d = (1 + A1) · R1* · i1d* viq = Lσ · *ω₀ · i1d* + (1 + AM) · M*²L2* · ω₀ · λ2d*M*The d- and q-axis primary voltage changes Δv1d and Δv1q are expressed in Equations (60) and (61) derived from Equations (56), (57), and (58) and (59), and the primary resistance change A1 and the excitation inductance change AM are expressed in Equations (62) and (63) derived from Equations (60) and (61). Δv1d = v1d - v1d* = A1 · R1* · i1d* Δv1q = v1q - v1q* =AM · M*2L2* · ω₀ λ2d*M*A1 = Δv1dR1* i1d*AM = Δv1qM*²L2* · ω₀ · λ2d*M*Since λ2d* = M* · i1d* when the excitation command is unchanged, the excitation inductance change AM is AM = Δv1qM*²L2* · ω₀ · i1d*As can be seen from the foregoing, it is possible to identify the primary resistance R1 and the excitation inductance M using the primary voltage change during induction motor idling operation. That is, the primary resistance change A1 can be derived from the d-axis primary voltage change Δv1d, and the excitation inductance change AM can be derived from the q-axis primary voltage change Δv1q. If the secondary resistance command R2* is in coincidence with the actual secondary resistance R2, the slip frequency command ωs* may be calculated from Equation (18). However, the actual secondary resistance R2 changes with changes in temperature. According to the invention, the δ-axis primary voltage change Δv1δ is utilized to calculate the secondary resistance change K and the calculated secondary resistance change K is utilized to correct the secondary resistance command R2*. The corrected secondary resistance command is used in calculating the slip frequency command ωs*. That is, the slip frequency command ωs* is calculated from the following equation: ωs* = (1 + K) · R2*L2* · i1q*λ2d*/M*The primary resistance R1 changes with changes in temperature. However, the secondary resistance correction is free from the influence of the primary resistance change since the δ-axis primary voltage change Δv1δ contains no component related to the primary resistance, as can be seen from Equation (50). In this respect, the invention is similar to the vector control circuit of Fig. 1. However, the conventional vector control apparatus is quite different from the invention in that the vector control is made only on a single coordinate system (d, q). Referring to Fig. 7, there is shown a schematic block diagram of a vector control apparatus embodying the invention. The vector control apparatus is arranged to control excitation currents iu, iv and iw that an inverter 40 applies to an induction motor IM by utilizing motor-flux and motor-torque command current signals i1d* and i1q*. The induction motor IM has three-phase stator windings which are energized by the output of the inverter 40 and a rotor coupled to drive a mechanical load. The inverter 40 includes a plurality of parallel pairs of series-connected switching element arranged and controlled to convert DC input power into AC output power having adjustable frequency and voltage magnitude. The inverter 40 is controlled by a pulse-width-modulation (PWM) circuit 41 which includes a PWM waveform generator, a triangle waveform generator and a gating circuit. The PWM waveform generator receives a triangle wave signal from the triangle waveform generator and controls the gating circuit to produce gating pulses so as to periodically switch the respective switching elements of the inverter in a predetermined sequence and at a desired frequency. The vector control apparatus includes a rotor speed sensor 42 connected to a pulse pickup transducer PP. This transducer is associated with the rotor of the induction motor IM for producing a series of electric pulses of a repetition rate directly proportional to the speed of rotation of the rotor. The rotor speed sensor 42 receives the electric pulses and produces an actual rotor angular velocity signal ωr indicative of the sensed rotor angular velocity. The actual rotor angular velocity signal ωr is fed to a calculation circuit 43 which receives a command signal λ2d*/M*. The calculation circuit 43 produces a command signal which remains at a value λ2d*/M* when the actual speed signal ωr is less than a predetermined value and decreases as the actual speed signal ωr increases when the actual speed signal ωr exceeds the predetermined value. The command signal is applied from the calculation circuit 43 to a calculation circuit 44 where a secondary flux command signal in terms of the primary current command value i1d* is calculated from Equation (8) as i1d* = λ2dM (1 + L2R2 P) The actual speed signal ωr is also applied to a summing circuit 45 which subtracts it from a speed command signal ωr* to provide an error output signal. In order to enhance the induction motor control for stability and response time, a proportional plus integral operation is provided on this error signal in a proportional plus integral circuit 46 to produce a torque command signal i1q*. These command signals i1d* and i1q* are applied to a first coordinate converter 47. The first coordinate converter 47 utilizes the command signals i1d* and i1q* to calculate a γ-axis primary current command value i1γ* and a phase angle ψ of the γ-axis of the coordinate system (γ, δ) held in coincidence with the direction of the primary current I1 with respect to the d-axis of the coordinate system (d, q) held in coincidence with the direction of the secondary flux as ψ = tan⁻¹(i1q*/i1d*), I1 = i1d*² + i1q*²The calculated phase angle ψ is fed to a calculation circuit 48 which utilizes the calculated phase angle in the form of sinψ and cosψ, along with the calculated value λ2d*/M* fed from the calculation circuit 44 and the primary voltage angular frequency 0, to calculate γ- and δ-axis primary voltage command values v1γ* and v1δ* from Equations (23) and (24). The vector control apparatus also includes a second coordinate converter 50 which senses two excitation currents iu and iv supplied from the inverter 40 to the induction motor IM and converts them into γ- and δ-axis primary current signals i1γ and i1δ. The γ-axis primary current i1γ is supplied to a summing circuit 51 which subtracts it from the γ-axis primary current command signal i1γ* to provide an error signal. A proportional plus integral operation is provided on this error signal in a proportional plus integral circuit 52 to produce a γ-axis primary voltage change signal Δv1γ. The signal Δv1γ is applied to a summing circuit 56 which adds it to the command signal v1γ* to correct the command signal viγ*. The corrected signal viγ is applied to a coordinate transformer 58. Similarly, the δ -axis primary current signal i1δ is fed to a summing circuit 53 which subtracts it from a δ-axis primary current command signal i1δ* to provide an error signal. A proportional plus integral operation is provided on this error signal in a proportional plus integral circuit 54 to produce a δ-axis primary voltage change signal Δv1δ. The signal Δv1δ is then applied to a summing circuit 57 which adds it to the δ-axis primary voltage command signal v1δ* to correct the command signal v1δ*. The corrected signal v1δ is applied to the coordinate transformer 58. The coordinate transformer 58 receives the corrected signals v1γ and v1δ and produces a signal |V1| indicative of the magnitude of the primary voltage vector V1 and a value indicative of the phase angle of the primary voltage vector V1 with respect to the γ-axis. The value |V1| is fed directly to the PWM circuit 41, whereas the value is fed to the PWM circuit 41 through a summing circuit 59 where it is added to an value ϑ (=ω0·t) to be described later. The PWM circuit 51 converts the values |V1| and + ϑ into primary voltage command signals causing the inverter 40 to produces three-phase excitation currents iu, iv and iw to the induction motor IM. The numeral 60 designates a secondary resistance change calculation circuit which utilizes the command signal λ2d*/M* fed thereto from the calculation circuit 43, the command signal i1d* fed thereto from the calculation circuit 44, the command signal i1q* fed thereto form the proportion plus integral circuit 46, the primary voltage angular velocity ω0 fed thereto from a summing circuit to be described later, the command signal i1γ* fed thereto from the first coordinate converter 47 and the command signal Δi1δ fed thereto from the proportional plus integral circuit 54 to calculate a secondary resistance change K from Equation (53). The calculated secondary resistance change K is fed to a slip angle frequency calculation circuit 61 which utilizes it, along with the command signals λ2d*/M* and i1q*, to calculate a slip frequency ωs from Equation (65). If a digital computer is used to make calculations at the circuits of Fig. 7, the slip frequency ωs is calculated as follows: The secondary resistance change K and the slip frequency ωs are calculated in synchronism with a series of clock pulses. The slip factor calculation circuit 61 uses the secondary resistance value R2n-1 calculated in the last or (n-1)th cycle of execution of the program to calculate the secondary resistance value S2n in the present or nth cycle of execution of the program. Assuming now that Kn is the secondary resistance change value calculated in the nth cycle of execution of the program, R2n is the secondary resistance value calculated in the nth cycle of execution of the program, and a predetermined value R2* is assigned to an initial value R20 for the secondary resistance value R2n, successive calculations are performed as follows: First calculation: R21 = (1 + K1) · R20 =(1 + K1) · R2* Second calculation: R22 = (1 + K2) · R21 = (1 + K2) · (1+K1) · R2* · · · Nth calculation: R2n = (1 + Kn) · R2(n - 1) = (1 + Kn) · (1 + Kn - 1) ··· (1 + K1) · R2* Assuming that ωsn is the slip frequency value calculated in the nth cycle of execution of the program, the value ωsn is given as ωsn = (1 + Kn) · ωs(n - 1) The value ωs(n-1) is calculated and stored in the (n-1)th cycle of execution of the program and it is used, along with the value Kn, to calculate the value ωsn from Equation (66). The initial value ωs1 for the slip frequency ωs is given as ωs1 = (1 + K1) · R2*(1/L2*) · i1q*/(λ2d*/M*) The calculated slip frequency ωs* is fed to the summing circuit 62 which adds it to the sensed rotor angular velocity ωr to provide a primary voltage angular frequency command signal ω0 which is then fed to an integrator circuit 63. The integrator circuit converts it into an angular position signal ϑ indicative of the angular position of the secondary flux. The angular position signal ϑ is then fed to the summing circuit 64. The numeral 65 designates an identification circuit operable in response to an output from a comparator 66. The comparator 66 compares the torque command signal i1q* with a predetermined value, for example, equal to 5% of the rated torque current. When the torque command signal i1q* is less than the predetermined value, the induction motor IM is idling and the comparator 66 produces a command signal causing the identification circuit 65 to operate. The command signal is also applied to disable the secondary resistance change calculation circuit 60 since the vector control is subject to no influence of the secondary resistance change while the induction motor IM is idling. The identification circuit 65 measures the γ-axis primary voltage change signal Δv1γ and the d-axis primary current command signal i1d* during induction motor idling operation and utilizes them to calculate a primary resistance change A1 from Equation (62). The calculated primary resistance change A1 is utilized to identify the primary resistance R1. The identification circuit 65 also measures the δ-axis primary voltage signal Δv1δ, the primary voltage angular frequency ω0 and the signal λ2d*/M* and utilizes them to calculate an excitation inductance change AM from Equation (63). The calculated excitation inductance change AM is used to identify the excitation inductance M²/L2. In order to calculate the γ-axis primary voltage command v1γ* , from Equation (25), with regard to the differentiating operator P, the calculation circuit 48 may be arranged to use the term R1*·(1 + Lσ/R1·P) in place of the term R1*. This is effective to enhance the vector control for control accuracy and response time. Referring to Fig. 8, there is shown a second embodiment of the vector control apparatus of the invention. The second embodiment is similar to that of the first embodiment except for the arrangement of the proportional plus integral circuits 70 and 74. Like reference numerals have been applied to Fig. 8 with respect to the equivalent components shown in Fig. 7. With the secondary flux change being ignored, the following equations can be derived from Equation (19): v1γ = R1 · i1γ + Lσ · P · i1γ + M²/L2 · ω₀ · (λ2d/M) · sinψ v1δ = Lσ · ω₀ · i1γ + Lσ · P · i1δ + M²/L2 · ω₀ · (λ2d/M) · cosψ As can be seen from Equations (67) and (68), each of the v1γ and v1δ changes by a value corresponding to the time rate of change of the corresponding one of the v1γ and v1δ with a rapid change in the primary current. That is, the δ-axis primary voltage change contains a component related to the secondary resistance change and also a component related to the time rate of change of the primary current, whereas the γ-axis primary voltage change contains a component related to the primary resistance and excitation inductance changes and also a component related to the time rate of change of the primary current. In this embodiment, both of (1) the primary voltage changes (Δv1γ and Δv1δ) which contain the terms Lσ·P·i1γ and Lσ·P·i1δ, and (2) the primary voltage changes (Δv1 I and Δv1δI) which do not contain the terms Lσ·P·i1 and Lσ·P·i1δ are calculated. The primary voltage changes Δv1γ and Δv1δ are used to control the primary voltage. The primary voltage changes Δv1γI and Δv1δI are used to correct the secondary resistance change and identify the primary resistance. The proportional plus integral circuit 70 includes a proportional element 71, an integral element 72 and a summing circuit 73. The proportional element 71 calculates a value (i1γ* - i1γ) x Lσ/Ts corresponding to Lσ·P·i1γ where Ts is the calculation time period. The integral element 72 integrates the value (i1γ* - i1γ). The integrated value is added to the calculated value (i1γ* - i1γ) x Lσ/Ts in the summing circuit 73. The added value Δv1γ is fed to the summing circuit 56. Similarly, the proportional plus integral circuit 74 includes a proportional element 75, an integral element 76 and a summing circuit 77. The proportional element 75 calculates a value (i1δ* -i1δ) x Lσ/Ts corresponding to Lσ·P·i1δ. The integral element 76 integrates the value (i1δ* - i1δ). The integrated value is added to the calculated value (i1δ* - i1δ) x Lσ/Ts in the summing circuit 77. The added value Δv1δ is fed to the summing circuit 57. The values (i1γ* - i1γ)/Ts and (i1δ* - i1δ)/Ts are calculated by differentiating elements. With this arrangement, the values Δv1γI and Δv1δ1 are free from the influence of a sudden primary current change. It is, therefore, possible to improve the accuracy with which the secondary resistance is corrected and the primary current is identified. Referring to Fig. 9, there is shown a modified form of the second embodiment where the δ-axis primary voltage change signal Δv1δI is fed to the secondary resistance change calculation circuit 60 through a filter 78 which provides a time lag of first order to the δ-axis primary voltage change signal Δv1δI. Since the δ-axis voltage change signal Δv1δI contains ripples particularly at low frequencies, it is desirable to remove the ripples to provide a stable secondary resistance change correction. The time constant of the filter 78A is varied in inverse proportion to the primary voltage angular frequency ω0. The filter transfer function G(S) is represented as G(S) = 1/1 + ST1 where T1 = 1/f0 = 2π/ω0, T1 is the time constant of the filter, f0 is the output frequency of the inverter 40, and ω0 is the primary angular frequency. For this purpose, a time constant setting circuit 79 receives a primary voltage angular frequency signal ω0 from the summing circuit 62 to vary the time constant of the filter 78 in inverse proportion to the primary voltage angular frequency ω0. It is desirable to provide a limiter 79a between the filter 78 and the time constant setting circuit 79 for varying the filtering effect according to the induction motor speed. Referring to Fig. 10, there is shown a third embodiment of the vector control apparatus of the invention. The third embodiment is similar to that of the first embodiment except that the secondary resistance change calculation circuit 60 is removed and replaced with a proportional plus integral circuit 80. Like reference numerals have been applied to Fig. 10 with respect to the equivalent components shown in Fig. 7. The proportional plus integral circuit 80 receives an input from a summing circuit 81 which subtracts the δ-axis primary voltage change Δv1δ fed from the proportional plus integral circuit 54 from a δ-axis primary voltage change command value Δv1δ* (= 0). The proportional plus integral circuit 80 calculates a slip frequency change Δωs from the present slip frequency command value ωs*. The calculated slip frequency change Δωs is fed from the proportional plus integral circuit 80 through a switch 82 to a summing circuit 83 where it is added to the slip frequency command value ωs* fed from the slip frequency calculation circuit 61. The switch 82 opens to interrupt the signal from the proportional plus integral circuit 80 to the summing circuit 83 in response to the command signal from the comparator 66, that is, when the induction motor IM is idling. The slip frequency calculation circuit 61 calculates the slip frequency command value ωs* from the following equation with the second resistance R2 being assumed to be unchanged from its command value: ωs = R2*L2* · i1q*λ2d*/M*The slip frequency command value ωs* is fed from the summing circuit 83 to the summing circuit 62. With this arrangement, the slip frequency command value is automatically corrected according to the secondary resistance. It is to be understood that the proportion plus integral circuits 52 and 54 may be replaced with the proportional plus integral circuit 70 and 74 of Fig. 8 in order to improve the accuracy with which the secondary resistance is corrected and the primary current is identified. Referring to Fig. 11, there is shown a modified form of the third embodiment. The δ-axis primary voltage change Δv1δ caused by a secondary resistance change is given by Equation (50). As can be seen from Equation (50), the δ-axis primary voltage change Δv1δ changes in direct proportion to the primary angular frequency ω0. For this reason, the primary angular frequency ω0 and thus the δ-axis primary voltage change Δv1δ are very small in a low frequency region or a motor locked condition. Therefore, the secondary resistance correction response is slow since the values Δv1δ and Δv1δI are very small. This modification improves the response time by providing a gain control circuit 84 which varies the gain Kp of the proportional plus integral circuit 80 in inverse proportion to the primary angular frequency ω0 as Kp = Kp* x ωOTRQ/ω0 where Kp* is the gain of the proportional plus integral circuit 80 at ω0TRQ, and 0TRQ is the ground angular frequency. It is preferable to enhance the operation stability of the proportional plus integral circuit 80 by providing a limiter 85 which limits the gain Kp between lower and upper limits Kp1 and Kp2. The primary angular frequency ω0 is set at ω0OTRQ and the gain Kp is set at Kp* if the primary angular frequency ω0 is in a steady output region. Referring to Fig. 12, there is shown a fourth embodiment of the vector control apparatus of the invention. The fourth embodiment is similar to that of the third embodiment except that a multiplying circuit 90 is provided. Like reference numerals have been applied to Fig. 12 with respect to the equivalent components shown in Fig. 10. When a sudden change occurs in the torque current command signal i1q* or the excitation current command signal λ2d*/M*, the slip frequency ωs will change. With the use of a proportional plus integral circuit arranged to produce a slip frequency change signal Δωs, the slip frequency change signal should change with a change in the command signal i1q* or λ2d*/M*. For this reason, the correction for secondary resistance changes has a slow response to a change in the torque current command signal i1q* or the excitation current command signal λ2d*/M*. This problem can be eliminated by arranging the secondary resistance correcting circuit in a manner to directly output the secondary resistance change K. Using the secondary resistance change K, the slip frequency is expressed as ωs = (1 + K) · R2*L2* · i1q*λ2d*/M* = R2*L2* · i1q*λ2d*/M + K · R2*L2* · i1q*λ2d*/M = ωs* + Δωs Assuming that the secondary resistance change K is a constant, the slip frequency change Δωs changes with a change in the command signal i1q* or λ2d*/M*, as can be seen from Equation (70). The proportional plus integral circuit 80 receives an input from the summing circuit 81 which subtracts the δ-axis primary voltage change Δv1δ fed from the proportional plus integral circuit 54 from a δ-axis primary voltage change command value Δv1δ* (= 0). The proportional plus integral circuit 80 calculates a secondary resistance change K. The calculated secondary resistance change K is fed from the proportional plus integral circuit 80 through the switch 82 to the multiplying circuit 90 where it is multiplied by the slip frequency command signal ωs* fed from the slip frequency calculation circuit 61. The product Δωs = K x ωs* is added to the slip frequency command signal ωs* fed from the slip frequency calculation circuit 61 in the summing circuit 83. The output of the summing circuit 83 is coupled to the summing circuit 62. The switch 82 opens to interrupt the signal from the proportional plus integral circuit 80 to the multiplying circuit 90 in response to the command signal from the comparator 66, that is, when the induction motor IM is idling. Referring to Fig. 13, there is shown a modification of the fourth embodiment. In this modification, the proportion plus integral circuits 52 and 54 are replaced with the proportional plus integral circuit 70 and 74 of Fig. 8 in order to improve the accuracy with which the secondary resistance is corrected and the primary current is identified. Referring to Fig. 14, there is shown another modified form of the fourth embodiment. The δ-axis primary voltage change Δv1δ caused by a secondary resistance change is given by Equation (50). As can be seen from Equation (50), the δ-axis primary voltage change Δv1δ changes in direct proportion to the primary angular frequency ω0. For this reason, the primary angular frequency ω0 and thus the δ-axis primary voltage change Δv1δ are very small in a low frequency region or a motor locked condition. Therefore, the secondary resistance correction response is slow since the values Δv1δ and Δv1δI are very small. This modification improves the response time by providing a gain control circuit 91 which varies the gain Kp of the proportional plus integral circuit 80 in inverse proportion to the primary angular frequency ω0 as Kp = Kp* x ωOTRQ/ω0 where Kp* is the gain of the proportional plus integral circuit 80 at ω0TRQ, and ω0TRQ is the ground angular frequency. It is preferable to enhance the operation stability of the proportional plus integral circuit 80 by providing a limiter 92 which limits the gain Kp between lower and upper limits Kp1 and Kp2. The primary angular frequency ω0 is set at ω0TRQ and the gain Kp is set at Kp* if the primary angular frequency ω0 is in a steady output region. As described in connection with Figs. 11 and 14, The δ-axis primary voltage change Δv1δ caused by a secondary resistance change is given by Equation (50). As can be seen from Equation (50), the δ-axis primary voltage change Δv1δ changes in direct proportion to the primary angular frequency ω0. For this reason, the primary angular frequency ω0 and thus the δ-axis primary voltage change Δv1δ are very small in a low frequency region or a motor locked condition. Thus, the secondary resistance correction response is slow since the values Δv1δ and Δv1δI are very small. It is, therefore, desired to increase the accuracy with which the secondary resistance change correction is made and to shorten the identification time. As can be seen from Equation (50), the δ-axis primary voltage change Δv1δ is in direct proportion to the primary voltage angular frequency ω0. Since the primary voltage angular frequency ω0 is equal to the slip frequency s in a motor clocked condition (ωr = 0), the δ-axis primary voltage change Δv1δ is in direct proportion to the slip frequency ωs. The slip frequency command value ωs* is given as ωs* = R2*L2* · i1q*λ2d*/M*When the torque current command value i1q* is small (at low load conditions), the slip frequency command value ωs* and thus the δ-axis primary voltage change Δv1δ are small. A mechanical brake, which is normally used with the induction motor IM, permits the induction motor IM to drive in a motor locked condition. If the torque current command value i1q* is set at a great value (for example, 50% to 100% of its maximum value) with the application of braking to drive the induction motor in a motor locked condition, the slip frequency command value ωs* and thus the δ-axis primary voltage change Δv1δ will be great. The great δ-axis primary voltage change Δv1δ is used to calculate the secondary resistance change from Equation (53) or operate the proportional plus integral circuit 80 so as to increase the accuracy of the secondary resistance change correction and to shorten the identification time. Fig. 15 is a flow diagram of the programming of the digital computer used in the induction motor vector control apparatus to calculate the secondary resistance change. The computer program is entered at the point 102. At the point 104 in the program, braking is applied to the induction motor IM. At the point 106 in the program, the torque current command value i1q* is set at a great value (for example, 50% to 100% of its maximum value). At the point 108 in the program, the value (1 + K) is calculated as a function of the δ-axis primary voltage change Δv1δ from Equation (53). At the point 110 in the program, the calculated value (1 + K) is held. The held value is used as an initial value of the secondary resistance change when the induction motor IM is returned into a normal operating condition. The program then proceeds to the end point 112. Fig. 16 is a flow diagram of the programming of the digital computer used in the induction motor vector control apparatus to operate the proportional plus integral circuit 80. The computer program is entered at the point 202. At the point 204 in the program, braking is applied to the induction motor IM. At the point 206 in the program, the torque current command value i1q* is set at a great value (for example, 50% to 100% of its maximum value). At the point 208 in the program, the proportional plus integral circuit 80 is operated with the δ-axis primary voltage change Δv1δ is applied to the input of the proportional plus integral circuit 80. At the point 210 in the program, a counter is set. At the point 212 in the program, a determination is made as to whether or not the counter accumulates a count corresponding to a time required for the identification. If the answer to this question is yes , then the program proceeds to the point 214. Otherwise, the program is returned to the point 212. At the point 214 in the program, the output of the proportional plus integral circuit 80 is held. The held secondary resistance change is used as an initial value of the secondary resistance change when the induction motor IM is returned into a normal operating condition. Following this, the program proceeds to the end point 216. | An apparatus employing a rotating Cartesian coordinate system (d, q) having a d-axis and q-axis, the d-axis being held in coincidence with a secondary flux of the induction motor (IM), for vector control of an adjustable-speed induction motor, comprising: means (40) for applying a primary current and voltage to drive the induction motor; means (PP, 42) sensitive to an induction motor angular velocity for producing an induction motor angular velocity value ωr; means (43) for producing a d-axis secondary flux command value λ2d*; means (44) for calculating a d-axis primary current command value i1d* as a function of the d-axis secondary flux command value λ2d* and a secondary time constant command value L2*/R2*; means (46) for producing a q-axis primary current command value i1q*; means (47) employing a rotating Cartesian coordinate system (γ, δ) having a γ-axis and δ-axis, the γ-axis being held in coincidence with the primary current I1 for calculating a γ-axis primary current command value i1γ* and a phase angle ψ of the γ-axis with respect to the d-axis as a function of the primary current command values i1d* and i1q*; means (48) for calculating the γ- and δ-axis primary voltage command values v1γ* and v1δ* as a function of the γ-axis primary current command value i1γ*, the phase angle ψ, the d-axis secondary flux command value λ2d*, and a primary voltage angular frequency ω0; means (50) for sensing the primary current and converting the sensed primary current into γ- and δ-axis primary current values i1γ and i1δ; means (51, 52) for caluclating a γ-axis primary voltage change Δv1γ as a function of the γ-axis primary current value i1γ and the γ-axis primary current command value i1γ*; means (53, 54) for calculating a δ-axis primary voltage change Δv1δ as a function of the δ-axis primary current value i1δ and a δ-axis primary current command value i1δ*; means (56) for adding the γ-axis primary voltage change Δv1γ to the γ-axis primary voltage command value v1γ* to produce a γ-axis primary voltage command signal v1γ; means (57) for adding the δ-axis primary voltage change Δv1δ to the δ-axis primary voltage command value v1δ* to produce a δ-axis primary voltage command signal v1δ; means (60) for calculating a secondary resistance change (K) as a function of the d-axis primary current command value i1d*, the q-axis primary current command value i1q*, the γ-axis primary current command value i1γ*, the d-axis secondary flux command value λ2d*, the primary voltage angular frequency ω0, the excitation inductance command value M*, the secondary inductance command value L2* and the δ-axis primary voltage change Δv1δ according to the equation 1 + K = M*²L2* · ω₀ · λ2d*M* · i1d* · i1q*² + i1γ* · i1q*² · Δv1δM*²L2* · ω₀ · λ2d*M* · i1d* · i1q*² - i1γ* · i1d*² · Δv1δ means (61) for correcting the secondary time constant command value L2*/R2* based upon the secondary resistance change; means (61) for calculating a slip frequency ωs as a function of the q-axis primary current command value i1q*, the d-axis secondary flux command value λ2d*, and the corrected secondary time constant command value; means (62) for adding the slip frequency ωs to the induction motor angular velocity value ωr to produce the primary voltage angular frequency ω0; and means (58, 41) for controlling the motor driving means to adjust the primary voltage based upon the primary voltage command signals v1γ and v1δ, and the primary voltage angular frequency ω0. The induction motor vector control apparatus as claimed in claim 1, wherein the δ-axis primary voltage change command value Δv1δ is zero. The induction motor vector control apparatus as claimed in claim 1, wherein the γ- and δ-axis primary voltage command value calculating means calculates the γ- and δ-axis primary voltage command values v1γ* and v1δ* as v1γ* = R1 · i1γ* + M²L2 · ω₀ · λ2d*M · sin ψ v1δ* = Lσ · ω₀ · i1γ* + M²L2 · ω₀ · λ2d*M · cos ψ where R1 is the primary resistance of the induction motor, M is the excitation inductance of the induction motor, and L2 is the secondary inductance of the induction motor, and wherein the induction motor vector control apparatus preferably further includes means for calculating a change A1 in the primary resistance R1 as a function of the primary resistance R1, the γ-axis primary voltage change Δv1γ, and the d-axis primary current command value i1d* when the induction motor is idling, means for correcting the primary resistance R1 based upon the calculated primary resistance change A1, means for calculating a change AM in the excitation inductance M as a function of the excitation inductance M, the δ-axis primary voltage change Δv1δ, the primary voltage angular frequency ω0, and the d-axis secondary flux command value λ2d* when the induction motor is idling, and means for correcting the excitation inductance M based upon the calculated excitation inductance change AM. The induction motor vector control apparatus as claimed in claim 1, wherein the γ- and δ-axis primary voltage command value calculating means calculates the γ- and δ-axis primary voltage command values v1γ* and v1δ* as v1γ* = R1(1 + LσR1 · P)i1γ* + M²L2 · ω₀ · λ2d*M · sin ψ v1δ* = Lσ · ω₀ · i1γ* + M²L2 · ω₀ · λ2d*M · cos ψ where R1 is the primary resistance of the induction motor, M is the excitation inductance of the induction motor, L2 is the secondary inductance of the induction motor, and P is a differentiating operator, and wherein the induction motor vector control apparatus preferably further includes means for calculating a change A1 in the primary resistance R1 as a function of the primary resistance R1, the γ-axis primary voltage change Δv1γ, and the d-axis primary current command value i1d* when the induction motor is idling, means for correcting the primary resistance R1 based upon the calculated primary resistance change A1, means for calculating a change AM in the excitation inductance M as a function of the excitation inductance M, the δ-axis primary voltage change Δv1δ, the primary voltage angular frequency ω0, and the d-axis secondary flux command value λ2d* when the induction motor is idling, and means for correcting the excitation inductance M based upon the calculated excitation inductance change AM. The induction motor vector control apparatus as claimed in claim 1, comprising: means (53) for subtracting the δ-axis primary current i1δ from the δ-axis primary current command value i1δ* to produce a difference (i1δ* - i1δ); means (75) for multiplying the difference (i1δ* - i1δ) by a leakage inductance Lσ to produce a multiplied value (i1δ - i1δ)·Lσ; means (76) for integrating the difference (i1δ* - i1δ) to produce an integrated value Δv1δI; means (77) for adding the multiplied value to the integrated value to produce a δ-axis primary voltage change Δv1δ; and wherein the δ-axis primary voltage change used by the means (60) for calculating a secondary resistance change is the integrated value Δv1δI. The induction motor vector control apparatus as claimed in claim 5, wherein the δ-axis primary voltage change command value Δv1δ is zero. The induction motor vector control apparatus as claimed in claim 5, further including filter means (78) having a time constant to provide a time lag of first order to the integrated value Δv1δI fed to the secondary resistance change calculating means, and means (79) for controlling the time constant of the filter means in inverse proportion to the primary voltage angular frequency ω0. The induction motor vector control apparatus as claimed in claim 5, wherein the γ-axis primary voltage change calculating means (70) includes: means (51) for subtracting the γ-axis primary current i1γ from the γ-axis primary current command value i1γ* to produce a difference (i1γ* - i1γ); means (71) for multiplying the difference (i1γ* - i1γ) by a leakage inductance Lσ to produce a multiplied value (i1γ* - i1γ)·Lσ; means (72) for integrating the difference (i1γ* - i1γ) to produce an integrated value Δv1γI; and means (73) for adding the multiplied value to the integrated value to produce the γ-axis primary voltage change Δv1γ, and wherein the γ- and δ-axis primary voltage command value calculating means (70, 74) preferably calculates the γ- and δ-axis primary voltage command values v1γ* and v1δ* as v1γ* = R1 · i1γ* + M²L2 · ω₀ · λ2d*M · sin ψ v1δ* = Lσ · ω₀ · i1γ* + M²L2 · ω₀ · λ2d*M · cos ψ where R1 is the primary resistance of the induction motor, M is the excitation inductance of the induction motor, and L2 is the secondary inductance of the induction motor. The induction motor vector control apparatus as claimed in claim 8, further including means for calculating a change A1 in the primary resistance R1 as a function of the primary resistance R1, the integrated value Δv1γI, and the d-axis primary current command value i1d* when the induction motor is idling, means for correcting the primary resistance R1 based upon the calculated primary resistance change A1, means for calculating a change AM in the excitation inductance M as a function of the excitation inductance M, the integrated value Δv1δI, the primary voltage angular frequency ω0, and the d-axis secondary flux command value λ2d* when the induction motor is idling, and means for correcting the excitation inductance M based upon the calculated excitation inductance change AM, wherein the induction motor vector control apparatus preferably further includes filter means having a time constant to provide a time lag of first order to the integrated value Δv1δI fed to the secondary resistance change calculating means, and means for controlling the time constant of the filter means in inverse proportion to the primary voltage angular frequency ω0. The induction motor vector control apparatus as claimed in claim 8, wherein the γ- and δ-axis primary voltage command value calculating means calculates the γ- and δ-axis primary voltage command values v1γ* and v1δ* as v1γ* = R1(1 + LσR1 · P)i1γ* + M²L2 · ω₀ · λ2d*M · sin ψ v1δ* = Lσ · ω₀ · i1γ* + M²L2 · ω₀ · λ2d*M · cos ψ where R1 is the primary resistance of the induction motor, M is the excitation inductance of the induction motor, L2 is the secondary inductance of the induction motor, and P is a differentiating operator, wherein the induction motor vector control apparatus preferably further includes means for calculating a change A1 in the primary resistance R1 as a function of the primary resistance R1, the integrated value Δv1γI and the d-axis primary current command value i1d* when the induction motor is idling, means for correcting the primary resistance R1 based upon the calculated primary resistance change A1, means for calculating a change AM in the excitation inductance M as a function of the excitation inductance M, the integrated value Δv1δI, the primary voltage angular frequency ω0, and the d-axis secondary flux command value λ2d* when the induction motor is idling, and means for correcting the excitation inductance M based upon the calculated excitation inductance change AM, and wherein the induction motor vector control apparatus preferably further includes filter means having a time constant to provide a time lag of first order to the integrated value Δv1δI fed to the secondary resistance change calculating means, and means for controlling the time constant of the filter means in inverse proportion to the primary voltage angular frequency ω0. An apparatus employing a rotating Cartesian coordinate system (d, q) having a d-axis and q-axis, the d-axis being held in coincidence with a secondary flux of the induction motor (IM), for vector control of an adjustable-speed induction motor, comprising: means (40) for applying a primary current and voltage to drive the induction motor; means (PP, 42) sensitive to an induction motor angular velocity for producing an induction motor angular velocity value ωr; means (43) for producing a d-axis secondary flux command value λ2d*; means (44) for calculating a d-axis primary current command value i1d* as a function of the d-axis secondary flux command value λ2d* and a secondary time constant command value L2*/R2*; means (46) for producing a q-axis primary current command value i1q*; means (47) employing a rotating Cartesian coordinate system (γ, δ) having a γ-axis and δ-axis, the γ-axis being held in coincidence with the primary current I1 for calculating a γ-axis primary current command value i1γ* and a phase angle ψ of the γ-axis with respect to the d-axis as a function of the primary current command values i1d* and i1q*; means (48) for calculating the γ- and δ-axis primary voltage command values v1γ* and v1δ* as a function of the γ-axis primary current command value i1γ*, the phase angle ψ, the d-axis secondary flux command value λ2d*, and a primary voltage angular frequency ω0; means (50) for sensing the primary current and converting the sensed primary current into γ- and δ-axis primary current values i1γ and i1δ; means (51, 52) for caluclating a γ-axis primary voltage change Δv1γ as a function of the γ-axis primary current value i1γ and the γ-axis primary current command value i1γ*; means (53, 54) for calculating a δ-axis primary voltage change Δv1δ as a function of the δ-axis primary current value i1δ and a δ-axis primary current command value i1δ*; means (56) for adding the γ-axis primary voltage change Δv1γ to the γ-axis primary voltage command value v1γ* to produce a γ-axis primary voltage command signal v1γ; means (57) for adding the δ-axis primary voltage change Δv1δ to the δ-axis primary voltage command value v1δ* to produce a δ-axis primary voltage command signal v1δ; means (61) for calculating a slip frequency command value ωs* as a function of the q-axis primary current command value i1q* and the d-axis secondary flux command value λ2d*; means (81) for calculating a difference of the δ-axis primary voltage change Δv1δ from a δ-axis primary voltage change command value; means (80) for calculating a slip frequency change Δωs as a function of the calculated difference; means (83) for adding the slip frequency change Δωs to the slip frequency command value ωs* to produce a slip frequency ωs; means (62) for adding the slip frequency ωs to the induction motor angular velocity value ωr to produce the primary voltage angular frequency ω0; and means (58, 41) for controlling the motor driving means to adjust the primary voltage based upon the primary voltage command signals v1γ and v1δ, and the primary voltage angular frequency ω0. The induction motor vector control apparatus as claimed in claim 11, wherein the δ-axis primary voltage change command value Δv1δ is zero, and/or wherein the slip frequency change calculating means is a proportional plus integral amplifier having a variable gain, and/or wherein the induction motor vector control apparatus further includes means for controlling the gain of the proportional plus integral amplifier in inverse proportion to the primary voltage angular frequency ω0, and/or wherein the γ- and δ-axis primary voltage command value calculating means calculates the γ- and δ-axis primary voltage command values v1γ* and v1δ* as v1γ* = R1 · i1γ* + M²L2 · ω₀ · λ2d*M · sin ψ v1δ* = Lσ · ω₀ · i1γ* + M²L2 · ω₀ · λ2d*M · cos ψ where R1 is the primary resistance of the induction motor, M is the excitation inductance of the induction motor, and L2 is the secondary inductance of the induction motor, wherein the induction motor vector control apparatus optionally further includes means for calculating a change A1 in the primary resistance R1 as a function of the primary resistance R1, the γ-axis primary voltage change Δv1γ, and the d-axis primary current command value i1d* when the induction motor is idling, means for correcting the primary resistance R1 based upon the calculated primary resistance change A1, means for calculating a change AM in the excitation inductance M as a function of the excitation inductance M, the δ-axis primary voltage change Δv1δ, the primary voltage angular frequency ω0, and the d-axis secondary flux command value λ2d* when the induction motor is idling, and means for correcting the excitation inductance M based upon the calculated excitation inductance change AM. The induction motor vector control apparatus as claimed in claim 11, wherein the γ- and δ-axis primary voltage command value calculating means calculates the γ- and δ-axis primary voltage command values v1γ* and v1δ* as v1γ* = R1(1 + LσR1 · P)i1γ* + M²L2 · ω₀ · λ2d*M · sin ψ v1δ* = Lσ · ω₀ · i1γ* + M²L2 · ω₀ · λ2d*M · cos ψ where R1 is the primary resistance of the induction motor, M is the excitation inductance of the induction motor, L2 is the secondary inductance of the induction motor, and P is a differentiating operator, wherein the induction motor vector control apparatus preferably further includes means for calculating a change A1 in the primary resistance R1 as a function of the primary resistance R1, the γ-axis primary voltage change Δv1γI and the d-axis primary current command value i1d* when the induction motor is idling, means for correcting the primary resistance R1 based upon the calculated primary resistance change A1, means for calculating a change AM in the excitation inductance M as a function of the excitation inductance M, the δ-axis primary voltage change Δv1δ, the primary voltage angular frequency ω0, and the d-axis secondary flux command value λ2d* when the induction motor is idling, and means for correcting the excitation inductance M based upon the calculated excitation inductance change AM. The induction motor vector control apparatus as claimed in claim 11, wherein the slip frequency change calculating means includes means for calculating a secondary resistance change K as a function of the calculated difference, and means for multiplying the secondary resistance change K by the slip frequency command ωs* to produce the slip frequency change Δωs. The induction motor vector control apparatus as claimed in claim 11, comprising: means (53) for subtracting the δ-axis primary current i1δ from the δ-axis primary current command value i1δ* to produce a difference (i1δ* - i1δ); means (75) for multiplying the difference (i1δ* - i1δ) by a leakage inductance Lσ to produce a multiplied value (i1δ* - i1δ)·Lσ; means (76) for integrating the difference (i1δ* - i1δ) to produce an integrated value Δv1δI; means (77) for adding the multiplied value to the integrated value to produce a δ-axis primary voltage change Δv1δ; means (80) for calculating a secondary resistance change K as a function of the calculated difference; means (90) for multiplying the calculated difference by the slip frequency command value ωs* to produce a slip frequency change Δωs; and/or wherein the δ-axis primary voltage change command value Δv1δ is zero, and/or wherein the slip frequency change calculating means is a proportional plus integral amplifier having a variable gain, and wherein the induction motor vector control apparatus preferably further includes means for controlling the gain of the proportional plus integral amplifier in inverse proportion to the primary voltage angular frequency ω0. | MEIDENSHA ELECTRIC MFG CO LTD; KABUSHIKI KAISHA MEIDENSHA | YAMADA TETUO; YAMAMOTO YASUHIRO; YAMADA, TETUO; YAMAMOTO, YASUHIRO |
EP-0490031-B1 | 490,031 | EP | B1 | EN | 19,981,125 | 1,992 | 20,100,220 | new | A01N57 | A01N25 | A01N25, A01N57 | A01N 25/32, A01N 57/12+M, A01N 25/12 | Method for protecting crops while eliminating crop injury due to pesticide interactions. | There are provided new granulated soil insecticidal-nematicidal compositions with concomitant reduced mammalian dermal toxicities, comprising an inert granular, biodegradable, sorptive carrier of renewable resource material and an insecticidally and nematicidally effective amount of O,O-diethyl S-{[(1,1-dimethylethyl)thio]methyl}phosphorodithioate or O,O-diethyl S-(ethylthiomethyl)phosphorodithioate. | The present invention relates to a method for protecting crops from attack by insects and nematodes while inhibiting the growth of undesirable plant species in the presence of said crops and reducing or eliminating crop injury due to interaction in the plant between terbufos, the insecticide-nematicide, and an AHAS inhibiting herbicide.Background of the InventionMonostory et al., Nehézvegyip. Kut. Intéz. Közl. 1979, 8, 57-64 discloses granulated plant protectors comprising a pesticide and a cellulose-rich by-product of furfurol manufacture. For the past four decades farmers have employed soil insecticides and nematicides for the protection of their crops and control of soil borne pests in the locus thereof. Many of these insecticides and nematioides have LD50's at or below 50 mg/kg of animal body weight and are extremely toxic to mammals, including humans, when introduced into the circulatory systems thereof whether by dermal absorption, inhalation or ingestion. As such, it has been long recognized that extreme care must be taken when handling these toxic materials, as for example during the manufacture, packaging, transportation, distribution or the application thereof to the soil in the locus of the crops sought to be protected.Two examples of soil insecticides that were developed nearly forty years ago and are still in as great demand today as they were in earlier years, are terbufos and phorate.Technical grade terbufos is reported in the Eight Edition of the Pesticide manual published by The British Crop Protection Council, to have an acute percutaneous LD50 on rabbits of 1.0 mg/kg of animal body weight. Phorate is reported to have an acute percutaneous LD50 on rats of 2.5-6.2 mg/kg of animal body weight.Thus it is not surprising to find that during these past four decades the agricultural industry has sponsored an extensive research effort to find methods of reducing the oral and dermal toxicities of these extremely toxic insecticide-nematicides. It has been found that when terbufos or phorate formulations are prepared on pumice or other abrasive carriers the applicators used for distribution of the formulated product are subject to severe wear and rapid erosion. Such erosion is costly and is a very significant problem especially in under developed and economically stressed countries.In addition to the above-said difficulties encountered in the preparation of terbufos and phorate formulations having reduced dermal toxicity, it is now evident that the high grade minerals from naturally occurring deposits which have been previously employed as carriers for insecticides and nematicides are being depleted. Thus, the quality of the carriers available today is beginning to deteriorate and with such deterioration formulators are encountering problems in (1) maintaining pesticide levels in the formulated products, (2) retaining effectiveness of the products in the field and (3) maintaining the LD50 levels once established for the formulated products.It is therefore an object of the present invention to provide a method for protecting crops by applying a new granulated pesticidal formulation composition having reduced mammalian dermal toxicity and comprising a solid inert granular, biodegradable, sorptive carrier obtained from a renewable resource and an insecticidally and nematicidally effective amount of O,O-diethyl S-{[(1,1-dimethylethyl)thio]methyl)phosphorodithioate and thereafter a herbicidally effective amount of an AHAS inhibiting herbicide.It is also an object of this invention to provide a method for protecting crops, comprising the application of a particulate pesticide composition with concomitant reduced mammalian dermal toxicity, comprising; an inert granular carrier prepared from a cellulosic complex and having a uniform quality, particle size, shape, bulk density, absorption capacity and pH, and having absorbed therein an insecticidally-nematicidally effective amount of terbufos. and thereafter the application of an AHAS inhibiting herbicide. The cellulosic carriers used in the formulation of this invention are also essentially non-dusting and non-abrasive, but readily decompose in or on the soil in the presence of soil and moisture.SUMMARY OF THE INVENTIONThis invention applies new granulated insecticidal-nematicidal compositions with reduced mammalian dermal toxicities, comprising; an inert granular, biodegradable, sorptive carrier of renewable resource material and an insecticidally and nematicidally effective amount of O,O-diethyl S-{[(1,1-dimethylethyl)thio]methyl}phosphorodithioate, (Terbufos).Specifically, the present invention relates to a method for protecting crops from attack by insects and nematodes while inhibiting the growth of undesirable plant species in the presence of said crops and reducing or eliminating crop injury due to interaction in the plant between terbufos, the insecticide-nematicide, and the AHAS inhibiting herbicide comprising; applying to soil in the locus of said crops, at or about the time of planting, an insecticidally-nematicidally effective amount of a cellulosic granular composition at least 90% of which is -8 +20 mesh granules having a bulk density of from 561 kg/m3 (35 lbs/cft) to 722 kg/m3 (45,0 lbs/cft) and a pH value between pH6 and pH8 said cellulosic composition being selected from the group of cellulosic material derived from deinked paper, deinked recycled paper, waste sulfate pulp or primary sludge from paper manufacture, wood fiber, primary wood pulp, secondary wood pulp or sludge from wood processing and absorbed therein from 5.0% to 15% by weight of terbufos and thereafter applying to the locus of the above-said terbufos treated crops approximately 2 to 4 weeks after planting and after said crops have emerged, a herbicidally effective amount of an AHAS inhibiting herbicide. The renewable resource material is a cellulosic material preferably obtained as deinked paper, recycled or otherwise, or as waste material from paper manufacture such as sulfate, sulfate pulp or primary paper sludge. Other cellulosic materials that may be employed as the renewable resource material from which the sorptive granular carriers can be prepared for use in the compositions of this invention are wood fiber from trees and primary and secondary wood pulp or sludge.Granular carriers that are especially useful in the preparation of the reduced dermal terbufos and phorate compositions of this invention generally have a bulk density of from 35 to 45 lbs/cft. They have a pH value between pH 6.0 and pH 8.0, contain from about 2.0% to 5.0% moisture, have a particle size in which at least about 90% by weight of the granules are -8, +20 mesh, based upon U.S. Standard sieve sizes. They are comprised of about 37% to 60% by weight of fiber and contain about 63% to 40% by weight of fillers normally used in the manufacture of paper such as kaolin, barium sulfate, titanium dioxide and the like.The granules that are used in the preparation of the compositions of this invention are distinguished from other granules heretofore employed as carriers for terbufos by reason of the fact that the above-said granules provide finished, free-flowing, non-abrasive granular compositions having significantly reduced mammalian dermal toxicities and provide slow release of the pesticide contained therein. The granules themselves can be prepared by the methods of manufacture described by H. E. Lowe etal in their UK patent GB 2188651B, application No. 8705107.4 filed March 5, 1987. However, it should be noted that the patentees describe the preparation of such a broad class of granular compositions by their processes that many of the granular compositions prepared by the patentees are not entirely satisfactory for use in the preparation of the compositions of the present invention.Only those granular compositions having the physical and chemical characteristics described above appear to provide the significantly improved mammalian dermal toxicities and controlled release rates of terbufos or phorate so vehemently sought after during the past four decades of research in the field of crop protection products.In accordance with this invention, compositions containing from about 2.0% to 20% by weight of terbufos can be prepared by spraying a fluidized or tumbling bed of dry particulated cellulosic material with about 2.0% to 20.0% by weight of technical grade terbufos or phorate. The particle size of the cellulosic granules is generally at least about 90% by weight of -8 mesh +20 mesh particle size and comprises about 75% to 98% by weight of the finished terbufos cellulosic particulate product. In practice, controlled particle size ranges of 8/20, 10/14, 12/20, or 12/24 mesh material are frequently used.Spraying of the cellulosic particles is continued for about 10 to 30 minutes, after which the sprayed granules are tumbled or blended for an additional 10 to 60 minutes and preferably 20 to 60 minutes to allow the terbufos to be uniformly distributed throughout the particulate mass and well absorbed into each granule.Where desired from about 2.0% to 7.0% by weight of vegetable oil or mineral oil may be applied as a liquid spray to the terbufos or phorate impregnated granules. However, unlike conventional terbufos granules prepared with montmorillonite, Mexican ROB (aluminum silicate), European Diaperl S-1 or the like, where the LD50 of the pesticide granules have heretofore, been further improved by the addition of small amount of oil, with the compositions of the present invention addition of a small amount of vegetable or mineral oil is tolerable but generally tends to increase the dermal toxicity of the terbufos granules rather than reduce the dermal toxicity thereof.A biocide may also be applied to the above-said granules to inhibit bacterial proliferation and the thus prepared granules may be dried using any convenient means, such as a fluid bed drier, belt dryer or the like.In addition to the above-said procedures for preparing terbufos cellulosic granular compositions with markedly reduced mammalian dermal toxicity, it is also found that further improvement in the mammalian dermal toxicity can be obtained by coating or partially coating the terbufos granules, with about 1.0% to 10.0% by weight of a natural or synthetic resin or polymer such as shellac, lacquer, or an acrylic polymer, polyvinyl acetate (PVA) or a polyvinyl chloride (PVC) resin or polyvinyl chloride/vinyl ester copolymer or homopolymer having a weight average molecular weight of about 200,000 to 400,000 and an inherent viscosity, as determined by ASTMD 1243, of about 1.00 to 1.32. For example, the PVC coating composition is prepared by admixing said PVC resin with about 5.0% to 15.0%, by weight, of a plasticizing agent such as butyl benzyl phthalate, diisononyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, tricresyl phosphate and trioctyl phosphate; about 0.3% to 2.0%, by weight, of a heat stabilizing agent for the resin, such as an organotin stabilizer, organo barium stabilizer, zinc/calcium stearate, epoxidized soybean oil, dibasic lead phosphite or the like; and about 0.5% to 2.0%, by weight, of a surface active agent, such as a nonionic surfactant.Nonionic surfactants useful in these PVC coating compositions include nonylphenoxy polyethoxyethanol, octylphenoxy polyethoxyethanol, alkylarylpolyether alcohol, alkyl polyether alcohol, mixtures thereof, or the like.Polymers used in in the PVC coating compositions were marketed by B.F. Goodrich as Geon, 138.Other plasticizers useful in the preparation of the above-said PVC coating compositions are epoxidized soybean oil, organic trimellitates, such as trioctyl mellitate or organic citrates such as acetyl tributylcitrate, or mixtures thereof.Other stabilizing agents effective for stabilizing the PVC resins include stearates, such as alkaline earth metal stearates, epoxidized soybean oil, secondary octyl tins and phosphites and organo barium and cadmium complexes, or mixtures thereof.Preferred PVC coated compositions of the present invention comprise about 2.0% to 20.0% by weight of terbufos; about 70.0% to 93.0%, by weight of a biodegradable, cellulosic granular material having a pH value between pH 6 and pH 8 and a particle size which is about 90% by weight -8 +48 mesh and coated with about 5.0% to 10.0%, by weight, of a polyvinyl chloride dispersion resin homopolymer/copolymer coating composition having a weight average molecular weight of about 260,000 to 340,000 and an inherent viscosity ASTMD 1243 of about 1.13 to 1.26 and containing about 5.0% to 15.0%, by weight, of a plasticizing agent selected from butyl benzyl phthalate and diisononyl phthalate; about 0.3% to 2.0%, by weight, of calcium/zinc stearate, a heat stabilizing agent for the resin; about 0.5% to 2.0% of the nonionic surfactant, nonylphenoxy polyethoxyethanol.The PVC or PVC/vinyl ester copolymer or homopolymer composition employed for coating or partially coating the terbufos cellulosic granular compositions may be prepared by mixing together about 12.5% to 50.0% by weight of the PVC resin or PVC/vinyl ester copolymer or homopolymer with about 0.3% to 5.0% by weight of a heat stabilizing agent; about 5.0% to 37.5% by weight of a plasticizing agent; and about 0.58% to 5% by weight of a surface active agent. This composition can then be sprayed onto the tumbling bed of particulate cellulosic, biodegradable, sorptive carrier containing from about 2.0% to 20.0% by weight of terbufos. When spraying is complete, the particulate composition is introduced into a dryer or drum furnace where it is heated to a temperature between about 120°C to 160°C in order to cure the PVC resin coating on the granules.Advantageously, the granulated formulations of this invention are highly effective for controlling symphylids, white grubs, seed corn beetles, billbugs, thrips, corn flea beetles, nematodes, wireworms, rootmaggots, cutworms, greenbugs, corn leaf aphids, Diabrotica spp., Tetanopsmyopaeformis, Delia brassicae, millipedes, onion maggots, and the like and may be applied to the soil in several ways. They may be applied to the soil surface as a broadcast application, a band beside the rows of planted crops, or a ring around individual plants such as in the case of banana trees. The compositions may also be applied in furrow when planting crops such as corn or in admixture with crop seeds such as canola, i.e. oil seed rape.A surprising advantage obtained when utilizing the formulations of this invention is the slow release of the terbufos which has been absorbed into the cellulosic granules. These cellulosic granular formulations do not permit rapid release or a burst of terbufos into the soil when said granular formulation is applied. Rather, these formulations provide a metered release of toxicant into the soil. This is especially important when the above-said pesticides are being employed for crop protection against insects and nematodes and said crops are being treated for weed control with an AHAS inhibiting herbicide such as a sulfonyl urea. Among the AHAS inhibiting herbicides, which have been reported to induce crop injury when used in conjunction with previously available terbufos compositions are primisulforon and nicrosulfuron. Surprisingly, it has now been found that the very metered release of terbufos from the granules of the formulations of the present invention limits the availability of the terbufos to the root systems of the treated plants and restricts the amount of pesticide that can be taken into the plant system. Thus, antagonism between the pesticide and the altered enzyme system in the plant, created by use of an AHAS inhibiting herbicide in the vicinity of said plant, is substantially eliminated and phytotoxicity in the crop essentially avoided.In practice, it is found that the application of a sufficient quantity of the cellulosic granular composition of the invention, to provide about 0.25 kg/ha to 8.0 kg/ha, preferably about 0.25 kg/ha to 4.0 kg/ha of the insecticide-nematicide, to the soil in which plants are planted or growing, will protect said plants from attack by insects and nematodes. Moreover, it is found that such treatment will provide extended protection for the plants against insect and nematode attack.In order to facilitate a further understanding of the invention, the following examples are presented primarily for the purpose of illustrating certain more specific details thereof. The invention is not to be deemed limited thereby except as defined in the claims. EXAMPLE 15% Terbufos cellulosic granular insecticide-nematicide composition having reduced mammalian dermal toxicityA horizontal rotary blender is charged with 750 gm of inert 12/20 mesh granular biodegradable, cellulosic sorptive particles having a pH value of 7.15 and a bulk density of 38.5 lbs/cft. Said cellulosic granules are about 39.0% by weight of cellulose fiber, 58% by weight of kaolin and about 4% by weight of titanium dioxide and/or barium sulfate from the manufacture of paper. The particle size distribution of the cellulosic granules is as follows: U.S. Sieve Size% By Weight#80#100#120.97#1679.04#2017.39#301.74pan0.84The blender is started and the tumbling mass of particulate material sprayed with 51 gm of technical grade terbufos (86.0% purity). Spraying is continued for twelve minutes and the sprayed mass blended for an additional ten minutes to assure even distribution of the terbufos throughout the particulate mass and excellent absorption into each particle. The composition thus prepared is then screened to assure a 12/20 mesh product having a minimal amount of fines and essentially no oversize. The bulk density of the finished product is 46.3 lbs/cft. The product is then stored in glass containers until the formulation is assayed for stability, attrition, mammalian toxicity and/or biologically evaluated.To determine stability of the terbufos in the above-said particulate composition, said composition is placed in a glass storage vessel and stored at 45°C for two months. The initial terbufos assay indicates the presence of 5.48% terbufos in the composition. Two months after storage at 45°C the product is again assayed and found to contain 5.43% terbufos.Resistance to attrition of the terbufos composition is found to be very high from the day of preparation and, surprisingly, improves during storage as can be seen below. Resistance to Attrition (%)Initial1 Month2 Months3 Months98.0%98.8%99.2%99.6%The mammalian dermal toxicity of the thus prepared composition is determined on male rabbits and the Rabbit Dermal LD50 is found to be 453 [326-627] mg/kg.EXAMPLE 25% Terbufos cellulosic granular insecticide-nematicide composition having reduced mammalian dermal toxicityThe procedure of Example 1 is repeated excepting that 10/14 mesh inert, biodegradable, cellulosic sorptive particles are substituted for the 12/20 mesh particles used in said example 1. The cellulosic granules are approximately 40% by weight cellulose fiber, 57% by weight of kaolin and 3% by weight of titanium dioxide and/or barium sulfate from the manufacture of paper. The particle size distribution of the cellulosic granules based on U. S. Sieve Size is as follows: U.S. Sieve Size% By Weight#80#8-104.97#10-1467.44#14-1618.16#16-509.43-300 The bulk density of these granules is 35.7 lbs/cft and they have a pH value of 7.7.The blender is charged with 750 gm of the above-said cellulosic particles and sprayed with 53.43 gm of technical grade terbufos (88.0% purity) for twelve minutes. After spraying of the terbufos is complete, the sprayed particles are sprayed with 0.75 gm of Red Dye Sudan IV and then blended for an additional ten minute period.The bulk density of the finished product is 39.2 lbs/cft and has a Rabbit Dermal of LD50 of 343 [244-482] mg/kg.The finished product comprises on a parts by weight basis 5.85% terbufos, 0.01% Red Dye Sudan IV and 94.14% cellulosic granules 10/14 mesh.EXAMPLE 3 5% Terbufos plus 5% soybean oil cellulosic granular insecticide-nematicide composition having reduced mammalian dermal toxicity The procedure of Example 2 is repeated excepting that the 750 gm of 10/14 mesh cellulosic particles are sprayed with 57.04 gm of technical grade terbufos (88% purity), then with 50 gm of soybean oil and thereafter 0.75 gm of Red Dye Sudan IV. The sprayed particles are blended for an additional ten minutes and then placed in a clear glass bottle.Determination of the dermal toxicity of the thus prepared composition indicates a Rabbit Dermal toxicity of 207 [167-258]mg/kg on male rabbits.On a parts by weight basis the finished product is 5.85% terbufos, 0.01% Red Dye Sudan IV, 5.85% Soybean Oil and cellulosic granules 10/14 mesh 88.29%.EXAMPLE 410% Terbufos cellulosic granular insecticide-nematicide composition having reduced mammalian dermal toxicityA horizontal rotary blender is charged with 750 gm of inert 8/20 mesh granular, biodegradable, cellulosic sorptive particles having a pH value of 7.15 and a bulk density of 38.5 lbs/cft. Said cellulosic granules are about 38% by weight of cellulose fiber, 58% by weight of kaolin and about 4% by weight of titanium dioxide and/or barium sulfate used in the manufacture of paper. The particle size distribution of the cellulosic granules is as follows: U.S. Sieve Size% By Weight#80.2#100.4#1481.7#1614.4#253.3pan0The blender is started and the tumbling mass of particulate material sprayed with 100.0 gm of technical grade terbufos (86.0% purity). Spraying is continued for twelve minutes and the sprayed mass blended for an additional ten minutes to assure even distribution of the terbufos throughout the particulate mass and excellent absorption into each particle. The composition, thus prepared, is then screened to assure an 8/20 mesh product having a very minimal amount of fines and essentially no oversize. The product is stored in a glass bottle until analyzed and found to contain 10.2% terbufos. The Rabbit Dermal LD50 for this product is 171 [122-214] mg/kg. It has a finished bulk density of 46.3 lbs/cft.The finished product is 10.20% by weight terbufos and 89.80% by weight 8/20 mesh cellulosic granules.EXAMPLE 510% Terbufos cellulosic granular insecticide-nematicide composition having reduced mammalian dermal toxicityThe procedure of Example 4 is repeated excepting that 12/20 mesh cellulosic granular material is substituted for the 8/20 mesh material used in said Example 4. The finished product has a bulk density of 46.3 lbs/cft and a Rabbit Dermal LD50 of 226 [163-314]-mg/kg. Addition of 2.0% by weight of linseed oil to the thus prepared product increases the mammalian dermal toxicity of the oil containing product giving it a Rabbit Dermal LD50 171 [122-214] mg/kg. EXAMPLE 615% Terbufos cellulosic granular insecticide-nematicide composition having reduced mammalian dermal toxicityA horizontal rotary blender is charged with 85 parts by weight of 8/20 mesh granular, biodegradable, cellulosic sorptive particles having a bulk density of 38.5 lbs/cft and a pH value of 7.15. The blender is rotated and sprayed with 17.04 parts by weight of technical grade terbufos (88% purity). Spraying of the terbufos is conducted for twelve minutes and the sprayed mass is permitted to blend for fifteen minutes thereafter. The thus prepared product contains 15% by weight of terbufos and has a Rabbit Dermal LD50 of 143 [73-276] mg/kg.The above-described procedure is repeated excepting that 12/20 mesh cellulosic granules are substituted for the 8/20 mesh granules used in the above-said composition. The product contains 15% by weight of terbufos and has a Rabbit Dermal LD50 of 135 [82-221] mg/kg. EXAMPLE 7Determination of Rabbit Dermal toxicities for all compositions described in Examples 1-13 aboveIn these tests, albino male rabbits of the New Zealand white strain and approximately 12 to 14 weeks of age are weighted and placed in individual cages equipped with an automatic watering device. The rabbits are fed adlibitum a non-medicated Purina Rabbit chow. Each animal is identified using a metal ear tag.The test site is prepared on each animal by clipping the trunk free of hair with electric clippers and a number 40 blade approximately 24 hours prior to testing. The test material, as received, is spread on a plastic wrap, moistened with tap water, the rabbit is placed ventral surface down on the wrap with the test material and the plastic wrap secured to the animal with adhesive tape. The area is then covered with a filter cloth wrapping to protect the plastic from damage. The area of application encompasses approximately 10% of the body surface area. The test material is held occluded under the impervious plastic wrap in continuous 24 hour contact with the shaved skin. At the end of the 24 hour exposure period the wraps are removed and any remaining test material removed by wiping the test site the cloth wrap.The treated animals are examined daily for toxic signs such as ataxia, salivation and prostration and death.The toxic signs (if any) and death are recorded for each animal and the results of the observations recorded. The LD50 calculations are then undertaken using the Weil Method.Comparative Rabbit Dermal toxicity data, mg/kg for the compositions prepared in examples 1-6 above are reported in Tables I and II below, where it can be seen that terbufos compositions prepared on the new cellulosic granules have significantly improved LD50's compared to compositions prepared on carriers obtained for non-renewable natural resources. Rabbit Dermal toxicity data: LD50's for 5% to 15% by weight of terbufos on a variety of granular carriersCompound % by weight terbufosGranular Cellulosic carrier U.S. mesh sizeDermal LD50 mg/kgGranular Mineral carrier U.S. mesh sizeDermal LD50 mg/kg5 %12/20453[326-627]24/48 Eastern European Diaperl S-1120[99-154]510/14343[244-482]24/48 Mexican ROB495%+ 5% oil10/14207[167-258]10%8/20171[122-214]10/20 Costa Rican Pumice5210%12/20226[163-314]24/48 South African montmorillonite136[123-149]10% + 2% oil12/20171[122-214]15%8/20143[73-276]24/48 U.S. montmorillonite10.215%12/20135[82-221]Rabbit Dermal toxicity data: LD50's for 15% to 20% by weight of phorate on a variety of granular carriersCompound % by weight terbufosGranular Cellulosic carrier U.S. mesh sizeDermal LD50 mg/kgGranular Mineral carrier U.S. mesh sizeDermal LD50 mg/kg15%24/48260[161-420]24/48 sand2824/48 U.S. montmorillonite12920%24/4880[51-127]24/48 attapulgite3724/48 U.S. montmorillonite64EXAMPLE 8Preparation of Terbufos cellulosic granular insecticidenematicide composition partially coated with shellac and having a reduced mammalian dermal toxicityA 400.0 gm sample of the terbufos composition prepared as described in Example 5 above is introduced into a bench top tumbler and the tumbler set in motion. A 1.36 kg can of white shellac (30.7% solids) is then well stirred and a 50 gm sample of the shellac taken from the can and sprayed on the surface of the tumbling mass of 10% terbufos. Since the shellac adheres to the surfaces of the spraying equipment on 23.88 gms of shellac is actually applied to the particles. Spraying is completed in about 3 minutes, but, the sprayed granules are permitted to tumble for an additional 20 minutes and until the particles have a shiny appearance. To assist drying the treated granules are permitted to tumble and subjected to blowing with a stream of air. The finished granules are only partially coated and contain about 1.8% by weight of shellac.EXAMPLE 9Preparation of Terbufos cellulosic granular insecticidenematicide composition partially coated with an acrylic polymer and having a reduced mammalian dermal toxicityThe procedure of example 15 is repeated excepting that an acrylic polymer marketed by Rohm Pharmaceutical Co. as Eudragit-E is used as the coating material. In this preparation 400.0 gm of the 10% terbufos granules prepared as in Example 5 are placed in a bench top tumbler and the tumbler bet in motion. This tumbling particles are then sprayed with 12.5 gm of the acrylic polymer Eudragit-E dispersed in 100 mL of acetone. Spraying is carried out over a 70 minute period and then tumbled for an additional 30 minutes with air being blown into the tumbler for the purpose of drying the particles. As the acrylic polymer adheres to equipment only 33.3 gm of the polymer is actually applied to the particles surfaces. This yields particles having 1.04% by weight of acrylic polymer as a partial coating.EXAMPLE 10Biological evaluation of Terbufos cellulosic granular insecticide-nematicide composition having reduced mammalian dermal toxicityIn these tests, banana trees are treated with a semi-circular application of the terbufos applied to the soil on cellulosic or pumice granules. The root systems are examined at 30 day intervals following application. Results obtained are as follows: A biological evaluation of terbufos cellulosic granular insecticide-nematicide for the control of banana nematodes (Radopholussimilis) indicate the formulation is effective in reducing these nematodes similar to the pumice formulation. Nematode counts obtained following June 26 applications in bananas ar as follows: FormulationCarrierDosage (gm ai/mat)No. of Radodophulus similis/100g rootsJulyAug.Sept.Terbufos 15%G(cellulose)3.011,0008,9177,417Terbufos 10%(pumice)3.07,0007,16713,000At 3 months after treatment, the cellulosic formulation is maintaining the Radopholus populations numerically below the economic threshold level of 10,000/100 g roots for an extended period compared to the pumice formulation. The nematode control for both treatments is reflected in the plant response in percent functional roots. FormulationCarrier(gm ai/mat)Functional Roots (%)JulyAug.Sept.Terbufos 15%G(cellulose)3.087.385.680.4Terbufos 10%(pumice)3.085.585.980.0The results indicate the cellulosic formulation of terbufos is equal to the pumice formulation which is recognized as highly effective in the control of nematodes present in banana plantations. | A method for protecting crops from attack by insects and nematodes while inhibiting the growth of undesirable plant species in the presence of said crops and reducing or eliminating crop injury due to interaction in the plant between terbufos, the insecticidenematicide, and the AHAS inhibiting herbicide, comprising; applying to soil in the locus of said crops, at or about the time of planting, an insecticidally-nematicidally effective amount of a cellulosic granular composition at least 90% of which is -8 +20 mesh granules having a bulk density of from 561 kg/m3 (35 lbs/cft) to 722 kg/m3 (45,0 lbs/cft) and a pH value between pH6 and pH8 said cellulosic composition being selected from the group of cellulosic material derived from deinked paper, deinked recycled paper, waste sulfate pulp or primary sludge from paper manufacture, wood fiber, primary wood pulp, secondary wood pulp or sludge from wood processing and absorbed therein from 5.0% to 15% by weight of terbufos and thereafter applying to the locus of the above-said terbufos treated crops approximately 2 to 4 weeks after planting and after said crops have emerged, a herbicidally effective amount of an AHAS inhibiting herbicide.A method according to Claim 1 wherein the AHAS inhibiting herbicide is primisulfuron or nicrosulfuron. | AMERICAN CYANAMID CO; AMERICAN CYANAMID COMPANY | BEHM JAMES ARTHUR; MILIONIS JERRY PETER; BEHM, JAMES ARTHUR; MILIONIS, JERRY PETER |
EP-0490033-B2 | 490,033 | EP | B2 | EN | 19,980,429 | 1,992 | 20,100,220 | new | A63H33 | null | A63H33 | A63H 33/04B, A63H 33/06C, A63H 33/10C | Construction toy | A construction toy system uses, as principle components, a connector (10) having one or more gripping sockets (14), and rod-like struts (13) having end portions configured to be received in the gripping sockets (14). The sockets (14) comprise pairs of gripping arms (16), formed of deflectable plastic material. Outer portions of the gripping arms (16) have concave grooves for lateral, snap-in assembly of struts (13) having complimentary cylindrical connector portions. The gripping arms (16) have locking projections (24) arranged to interlock with annular recesses (27) near the ends of the struts (13). The struts (13) have end flanges (26), received in a cavity at the closed end of the gripping socket (14). Certain forms of the connecting elements are designed so that an assembly of two such connector elements provides for sockets in each of two planes oriented at right angles to each other to form a right angle corner structure, for example, or a Tee-shaped structure. The system comprises a variety of connector elements, having one or more sockets arranged to be joined with struts, to form complex structural units. A plurality of single socket connector elements can be connected with a succession of crosswise oriented struts to form an articulated structure, of endless or finite length. Connector elements also may be joined to form connector assemblies with provision for mounting struts in several planar directions, Struts are provided in graduated sizes according to a predetermined length progression, such that one standard size strut can serve as the hypotenuse of a right isosceles triangle formed with struts of a smaller size. Complex structures can be assembled using right triangular subunits. The device is especially adapted for high volume production by injection molding techniques. | The invention is directed to constructions toys, and more particularly to novel and improved forms of construction toy, comprising hub-like conector elements and strut-like structural elements adapted to be removably engaged with the connector elements to form a composite structure, as defined in the preambles of claims 1 and 18. The invention is also directed to an adaptor element for such construciton toys.A variety of construction toys is known, which are comprised of combinations of conector elements and structural elements which can be combined in various forms to form composite structures. One example is disclosed in DE-A-35 24 467.The object of the invention is to provide construction toys incorporating a variety of unique and advantageous features enhancing their performances, which toys can be mass-produced on a low cost basis.In order to comply with this object, a constructional toy system is proposed which comprises the features of claims 1 and 18, respectively. Furthermore, an adaptor element is which comprises the features of claim 35 is proposed.Preferred embodiments and improvements of the invention are subject of the subclaims appended to the respective independent claims.The device of the present invention, while being of a kown general type, incorporates a variety of unique and advantageous features which greatly enhance its perfomance. At the same time, the device is designed to be mass produced by injection molding techniques, so as to be capable of manufacture on a low cost basis.A hub-like connector element is provided with a plurality of generally radially oriented sockets for receivng and lockingly engaging end portions of typical structural elements of strut-like configuration. The connecting sockets are designed to accomodate lateral snap-in insertion of the structural elements. The end extremities of the structural elements are formed with an annular groove, defining a flanged end. The sockets on the connector elements are defined by spaced pairs of gripping arms, and each arm includes an inwardly protruding locking projection arranged to be received in the annular groove of the structural element. Accordingly, upon lateral snap-in installation of a structural element, it is locked against axial withdrawal from the connector element.The strut-like structural elements, molded to be of circular cross section at the ends, are configured, in regions intermediate the ends in a generally X-shaped cross section. The X-shaped cross section is arranged for cooperation with the opposed locking projections of the gripping arms such that, when the structural element is oriented at 90° to its normal radial orientation in the connector element, it may be pressed laterally between a pair of gripping arms and snapped into locked position, with the locking projections engaging the X-shaped cross section to immobilize the structural element.Among the structural possibilities enabled by the last mentioned feature of crosswise gripping of structural elements is the assembly of articulated belt-like structures, which can be incorporated into dynamically operated toy structures, such as bulldozers, tanks, conveyor belts and the like, and also static structures such as catenary suspension elements.One form of connector element enables one connector to be joined with another, in planes which are disposed at right angles to each other. A pair of thus-joined connector elements provides for an assembly with structural elements in two principal planes. In addition, each of the available sockets still retains the ability to lockingly receive structural elements oriented at right angles to the principal plane of the hub-like connector element. In one modification, an assembly of connector elements can be provided which accommodates the mounting of strut elements extending in four planar directions from a central axis. Modified forms of such connector element assemblies are provided in which strut elements extend in three planar directions (forming a Tee-shaped joint) or in two planar directions (forming a right angular corner joint).The design and construction of the socket-forming recesses, on the one hand, and the ends of the strut elements, on the other hand, advantageously is such that the cooperative action of the rib and groove means serves to yieldably urge the strut elements axially into tight end face contact with the end wall of the recess. This provides for a significant degree of additional stability in the connection between the strut and connector.To particular advantage, the construction toy system includes a series of struts of graduated lengths, graduated in accordance with a predetermined formula such that when two struts of a given length in a series are joined with connector elements to form a right angularly related structure, the strut of the next larger length in the series is of an appropriate length to be joined in the assembly along the hypotenuse of the triangular structure. In this manner, a large structural assembly may be formed utilizing rigid triangular structural subassemblies of various different sizes for maximum strength and rigidity.In the new system, in which a series of strut elements of graduated lengths is provided according to the before- mentioned principle, a structure consisting of a pair of like strut elements of a given length in the series, mounted on opposite sides of a connector element so as to be coaxial, are equal in length to the length of a strut element two sizes larger in the series. This arrangement provides for an extraordinary degree of flexibility in the arrangement of structural parts in any assembly.A significant aspect of the foregoing geometric relationship is the fact that the strut elements can be assembled with the connector elements by lateral snap-in assembly, so that the center to center distance of a pair of connector elements does not have to be enlarged in order to receive a strut element. This enables a structure to be easily added to and/or modified even after it has reached a stage of substantial rigidity.For many dynamic structures, a driving relationship between a strut element, functioning as an axle, and an associated connector element may be desired. To this end, the construction toy system incorporates a drive element comprising a socket-forming recess of the type described, which is intended for the crosswise reception of a strut element functioning as an axle for an adjacent connector element. The drive element is formed with a laterally extending drive pin arranged to be received between adjacent spoke-like webs of a connector element, in order to lock the connector element in driving relation to the strut on which it is supported.For a more complete understanding of the above and other features and advantages of the invention, reference should be made to the following detailed description of preferred embodiments and to the accompanying drawing.Preferred embodiments are described in connection with the drawings, in which Fig. 1 is an elevational view, partly in section, of a hub-like connector element constructed according to the invention, with selected structural elements joined therewith.Fig. 2 is a greatly enlarged, fragmentary, perspective view of a portion of the connector element of Fig. 1.Fig. 3 is an enlarged, fragmentary view of the end portion of a strut-like structural element constructed in accordance with the invention.Fig. 4 is a cross sectional view as taken on line 4-4 of Fig. 3.Figs. 5, 6 and 7 are sequential views, as taken generally on line 7-7 of Fig. 1, showing progressive stages of lateral, snap-in insertion of a structural element into a socket of the connector element of Fig. 1.Figs. 8 and 9 are enlarged, cross sectional views as taken generally on lines 8-8, 9-9 respectively of Fig. 1. Fig. 10 is an elevational view of a strut-like structural element constructed according to the invention.Fig. 11 is a highly enlarged, fragmentary perspective view showing the structural element of Fig. 10 installed in a socket of a connector element at right angles to the normal radial orientation.Fig. 12 is a transverse cross sectional view as taken generally on line 12-12 of Fig. 11.Fig. 13 is a bottom perspective view of an adapter block element, for integrating the construction toy with certain popular, block-type construction toys.Fig. 14 is an elevational view, partly in section, of the adapter block of Fig. 13.Fig. 15 is a top plan view of the assembly of Fig. 14.Fig. 16 is a perspective view of an assembly of a pair of modified connector elements each with the other.Fig. 17 is an exploded view showing the component elements of the assembly of Fig. 16.Fig. 18 is a greatly enlarged, fragmentary perspective view of a connector element of Fig. 16.Fig. 19 is an elevational view of the assembly of Fig. 16.Fig. 20 is an enlarged, fragmentary sectional view, illustrating the manner in which a structural element of Fig. 19 is inserted in certain of the sockets of the connector element.Fig. 21 is a side elevational view of a single socket connector element constructed to receive one strut element oriented axially in a socket-forming recess and a second strut element in a hub bearing, disposed at right angles thereto.Fig. 22 is a side elevational view of a two element connector.Figs. 23-29 illustrate other modifications of connector elements.Fig. 30 is a group view illustrating a series of strut elements of graduated length and also the relationship of the length of a given strut of a series to smaller struts joined together coaxially by a connecting element.Fig. 31 is a greatly enlarged view illustrating the socket portion of a connecting element in cross section as joined with a strut element.Fig. 32 is an elevational view of an assembly of strut and connector elements arranged in triangular sub-units of increasing size.Fig. 33 is a top plan view of an articulated belt or tread structure constructed of a plurality of single unit connectors and a plurality of strut elements mounted in crosswise relation therein.Fig. 34 is a cross sectional view as taken along line 34-34 of Fig. 33. Figs. 35-39 are various views illustrating a modified form of connector element which is capable of assembly with a like connector element.Figs. 40, 41 illustrate a connector element of the type shown in Figs. 35-39, as assembled with a connector element of the type shown in Figs. 16-20.Fig. 42 is a perspective view of a drive element constructed for crosswise reception of a strut element serving as an axle, and provided with a driving lug.Fig. 43 is an elevational view of the driving element of Fig. 42, showing a strut element gripped in crosswise relation therein.Fig. 44 is a view, similar to Fig. 43, showing in addition a connector element received on the strut element and drivingly engaged for rotation therewith.Fig. 45 is an elevational view of a combined pulley and wheel-forming element.Fig. 46 is a side elevational view of a tire-like element adapted for assembly with the element of Fig. 45.Figs. 47, 48 are cross sectional views as taken generally on lines 47-47, 48-48 respectively of Figs. 45, 46.A hub-like connector element 10 is shown particularly in Fig. 1. The connector element includes a central hub cylinder 11 and radiating spokes 12. The illustrated form provides for the connection of eight, radially disposed structural elements 13.The radial spokes 12 support an array of eight sockets 14, each comprising an end wall 15 and spaced-apart, opposed gripping elements 16. The sockets 14 are radially disposed with respect to the central axis 17 of the connector, and the respective pairs of gripping elements 16 are desirably arranged on opposite sides of the radial axis of the socket, in generally parallel relation to such radial axis.The gripping elements 16 are provided in their outer portions with concave grooves 18, which are concentric about the radial axis 19 of the socket and extend from the outer end extremities 20 of the gripping elements a suitable distance toward the base wall 15 of the socket, typically about halfway.The strut-like structural elements 13 are of generally cylindrical construction at the their end extremities. The structural elements may have a nominal diameter of, for example, approximately 6,35 mm (0.250 inch),for cooperation with concave grooves 18 in the gripping elements formed on a diameter of the same dimension.As is apparent in Fig. 5, the arc of the grooves 18 serves to narrow the entrance area to a dimension significantly less than the 6,35 mm (0.250 inch) diameter of the structural element. The dimension at the throat or opening 21 may be on the order 5,334 mm (0.210 inch). Accordingly, it is desirable to form the lateral edges 22 of the gripping arms to diverge from the throat 21 to the outer lateral surface 23 of the gripping arm. An angle of divergence of about 15° is appropriate. This facilitates the lateral insertion of the structural element 13 into the grooves 18 by causing the gripping arms 16 to be laterally displaced and separated. Once the structural element is seated in the grooves 18, the gripping arms 16 close snugly about the structural element to retain it in position.Each of the gripping arms 16 is provided with a locking projection 24, desirably of semicylindrical configuration, extending at right angles to the radial axis of the socket defined by the gripping elements. In the illustrated construction, the projections 24 are of generally uniform cross section and extend from one side edge of the gripping arms 16 to the other, as shown best in the enlarged perspective view of Fig. 2.The locking projections 24 are spaced radially outward a short distance from the base wall 15 of the socket and define therewith a flange-receiving recess 25 at the inner or base end of the socket.As shown in Fig. 3, the end extremity of each of the structural elements 13 is configured such that a longitudinal cross section of the end portion is approximately the same as the longitudinal cross section of a socket 14, taken along its radial axis in a plane parallel to the flat sides of the connector element. The structural elements 13 include cylindrical end flanges 26 of a size and shape to be received in the flange-receiving recess 25 of the socket. Immediately adjacent the cylindrical end flange 26 is an annular groove 27 of a semicircular cross sectional configuration adapted to be received within the narrowed space between opposed locking projections 24. Immediately adjacent the annular groove 27 is a cylindrical gripping portion 28, which is adapted to be received in the concave grooves 18 and gripped snugly by the outer portions of the gripping arms 16. The axial length of the gripping portion 28 desirably corresponds to the effective length of the grooves 18. The cylindrical flange 26 may have an axial length of, for example, 1,575 mm (0.062 inch). The annular groove 27 and the locking projections 24 may have a typical radius of approximately, 1,575 mm (0.062 inch). For structural elements of 6,35 mm (1/4 inch) nominal diameter a suitable length overall for the gripping sockets 14 is about 8,89 mm (0.35 inch).A typical form of strut-like structural element 13 is shown in Fig. 10. The element may of course be of any length, and a typical construction toy set incorporating principles of the invention would utilize large numbers of such elements, of various appropriate lengths. To particular advantage, portons of the structural element between its respective end portions 30 are of an X-shaped cross sectional configuration, comprised of ribs 31, extending radially, typically at 90° angular intervals and preferably with the external surfaces 32 of the ribs lying on the cylindrical envelope of the element as defined by its cylindrical end portions.By properly dimensioning the thickness 33 of the ribs 31, and slightly beveling the outer sidewall portions thereof, as indicated at 34, the structural element is able to be pushed laterally into the open end of a radial socket 14 and forced between a pair of opposed locking projections 24, as reflected in Figs. 11 and 12, seating the projections in recesses 39 between adjacent ribs.The X-shaped cross section of the structural element may be periodically interrupted by one or more pairs of cylindrical portions 35 spaced apart a distance approximately equal to the width dimension 36 of the gripping arms 16. When the structural element is snapped into locked position on the projections 24, as shown in Figs. 11 and 12, the structural element is locked in position axially, laterally and rotationally. Alternatively, if the structural element is applied laterally into the radial socket 14 in one of its areas 37 in which adjacent cylindrical sections 35 are widely spaced, it is possible to adjust the position of the structural element along its axis, within limits.In a specifically advantageous embodiment of the invention, the width of the ribs 31 may be on the order of 0,236 mm (0.093 inch), tapered convergently in the outer portions, as is reflected particularly in Fig. 4. It will be understood that X-shaped configuration of the structural elements 13 is not limited in principle to the use of two pairs of ribs. For example, three pairs of ribs may be arranged at 60° angular spacing. Accordingly, the term X-shaped , as used herein, is to be interpreted as encompassing such alternatives.As reflected in Figs. 13 to 15, the present invention provides an adapter element 40 of block-like configuration, which is adapted to interface between conventional block-type construction elements and the construction toy elements of the present invention.In Figs. 14 and 15, for example, elements 41, 42 are block-like construction elements of a known type, constructed in the form of an open-sided block provided with a top wall 44 and sidewalls 45 to 48 forming an open cavity 49. The top wall 44 is provided with a plurality (eight in the illustration) of short circular projections 50. Also extending from the top wall 44 through the cavity 49 are three elongated tubular friction posts 51. In accordance with known design of the block-type construction elements 41, 42, the internal dimensions of the cavity 49 are such as to fit snugly about the external projections 50. In addition, the friction posts 51 are dimensioned to have tangential contact with the sides of the projections 50 when construction blocks are placed one atop the other. This enables, in a known manner, the plurality of construction blocks to be frictionally assembled to form a composite structure.The adapter block 40 includes a top wall 52 and sidewalls 53. In the illustrated arrangement, the adapter block is of square configuration, but other configurations are possible within the contemplation of the invention. Projecting from the top wall 52 are four elongated cylindrical projections 54 of a diameter and spacing corresponding to the short circular projections 50 of the construction blocks 41, 42. These cylindrical projections 54 may be inserted into the open cavity 49 of a construction block and desirably are of a length corresponding generally to the depth of the cavity 49.A tubular adapter sleeve 55 extends from the underside of the top wall 52, through the open cavity 56 in the adapter block 40. The internal diameter of the tubular sleeve is such as to snugly receive an end portion 30 of a structural element 13, as shown in Fig. 14. The tubular sleeve 55 is recessed below the open edge 57 of the adapter block side walls 53 so that the adapter block 40 may be assembled with a conventional construction block 41, 42 in an otherwise known manner.A connector element 70, shown in Figs. 16, 17, has the general snowflake configuration of the device described above, and has many of the structural features of the before mentioned device, but is specially modified to accommodate assembly with a second, similarly configured connector element oriented at right angles thereto. The connector element 70 is generally of a flat, open configuration, typically about 6,35 mm (1/4 inch) in thickness. At its center, the connecting element 70 has a solid, semi-cylindrical core 71. Guide walls 72, 73 extend from opposite sides of the core 71, in spaced-apart, parallel relation. The spacing between the guide walls 72, 73 is substantially equal to the thickness of the connector element, allowing for a second such element 70a to be received within the recess 74 defined by the spaced-apart guide walls 72, 73 and a flat transverse wall 75 which forms one side of the core 71 and is positioned on an axial plane passing through the connector element.Extending radially outward from the core are a plurality of spoke-like elements 76 to 78 which, at their outer ends, join with peripheral walls 79, 80. In the illustrated arrangement, the walls 79, 80 define seven sides of a generally octagonal structure, with the eighth side being open to accommodate the recess 74. As is evident in Fig. 17, the several walls 79 extend continuously from one spoke to the other (or from a spoke to the guide walls 72, 73). The wall 80, which lies directly opposite the recess 74 is, however, formed with a discontinuity in form of a gap 81 the function of which will be explained hereinafter.Each of the walls 79, 80 forms the end wall of a strut-receiving socket 82 (in the case of the walls 79) or 83 (in the case of the interrupted wall 80). Each of the sockets is defined by pairs of opposed gripping elements 84 provided internally with semi-cylindrical locking projections 85, which extend at right angles to the generally radial axis of the socket. The locking projections, in conjunction with the base walls 79, 80, define flange-receiving recesses 86. The outer portions of the gripping elements 84 are formed with concave grooves 87 concentric with respect to the generally radial axis 88 of the socket.As shown in Fig. 19, strut-like structural elements 90 are provided with cylindrical end flanges 91, adjacent annular grooves 92, and cylindrical portions 93 arranged to be received snugly in the concave grooves 87 of the gripping elements. The structural member 90 (sometimes referred to as a strut) normally is assembled with the connector element 70 by being pressed laterally into one of the sockets 82. The lateral entrance to the socket 82 is partially closed by a narrow throat section, defined by upper and lower edges 94 of the cylindrical grooves 87. Divergent guide surfaces 95 are provided to facilitate lateral insertion of the structural elements.To particular advantage, the configuration of the sockets and struts is such that, when a strut end is received in a socket, the flat flange end wall 91a of the strut is resiliently urged into firm face to face contact with the flat base wall 79 (or 80) of the socket. This arrangement adds significant stability and rigidity to an assembly of parts. The desired relationship is achieved by displacing the locking projections 85 slightly in the direction of the socket end wall 79, with respect to the normal position of the strut groove 92. Thus, when the strut is snapped into assembled position it is automatically pressed toward the bottom of the socket to urge the flat walls 91a and 79 into tight face to face contact.With reference now to the exploded view of Fig. 17, a second connector element 70a identical to the connector element 70 is oriented so that its principal plane lies at right angles to that of the element 70 and also so that its recess side (not shown in Fig. 17) faces the recess 74 of the element 70. When these two elements 70, 70a are moved together, in the direction of the arrow 96, the portion of the connector 70 to the left of the end wall 75 is received by the recess of the connector element 70a. Likewise, the recess 74 of the element 70 receives the right-hand portion of the element 70a. The completed assembly of the two connecting elements 70, 70a is evident in the perspective view of Fig. 16. The assembled connectors provide radially oriented strut-receiving recesses in two planes, so that the structural possibilities of the system are greatly enhanced.To secure the two connector elements 70, 70a in assembled relation, cooperating ribs and grooves are formed on the respective parts. The guide walls 72, 73 are provided with transverse detent grooves 97. These are arranged to receive appropriately located detent ribs 98 on the opposite connector element. The ribs 98, as indicated in Fig. 17, are formed on the radial spoke-like elements 77. During assembly of a pair of connector elements 70, 70a, as the projecting ribs 98 reach the outer end of the guide walls 72, 73, the guide walls are elastically displaced outwardly a distance sufficient to accommodate the presence of the ribs. This elastic displacement is facilitated by providing a small gap 81 in the recess wall 80. Thus, during the assembly process, the opposite halves of the divided wall 80 are displaced toward each other, facilitating the outward displacement of the guide walls 72, 73. This process is happening simultaneously on both of the connector elements 70, 70a, as will be understood.The single plane connector element described in Figs. 1 to 5 is formed with a symmetrical array of eight strut-receiving sockets. The individual connector elements 70, 70a, on the other hand, are formed with one less strut-receiving socket, by reason of the open-sided recess 74 at one side of the connector. Nevertheless, when the two elements are assembled, as reflected in Fig. 16, for example, each connector element contributes, in effect, a strut-receiving socket to the other connector element, so that there are four pairs of opposed sockets in each plane.When two of the connecting elements are assembled in the manner of Fig. 16, three opposed pairs of sockets on each connecting element are open and accessible for lateral insertion of a strut 90. However, in the case of one of the opposed pairs of sockets 83, 83a, normal lateral insertion of a strut is precluded by the immediate adjacency of outwardly extending gripping elements 84 carried by the opposite connecting element of the assembly.Insertion of a strut element 90 into the partially inaccessible sockets 83, 83a is facilitated by reason of the slotted recess wall 80. The slot or gap 81 therein enables limited outward displacement of the adjacent gripping arms 84 to enable a strut element to be cammed into position through a levering motion, illustrated schematically in Figs. 19 and 20. With reference to Fig. 19, the position of the strut element 90 shown in broken lines represents a typical starting position for inserting a strut into a socket 83a of a connecting element 70a. The end surface 100 of the strut is placed against an outer surface 101 of the adjacent gripping arm, and this serves somewhat as a guide as the strut is pushed laterally into the socket, while generally holding the angular orientation shown in Fig. 19. During this operation, there is an initial outward displacement of the opposed gripping arms, accommodated by the slot or gap 81 which tends to open up wider than normal. In addition, the recess guide wall 72 is deflected outward slightly and this is encouraged by a levering action of the strut element 90 in the direction of the arrow 102 of Fig. 19. This has the effect of prying upwardly against the guide surface 101, so that the adjacent gripping arm element 84 is displaced in the direction of the arrow 103 in Fig. 20. Levering of the strut continues until the flanged end of the strut snaps into place in the recess, as shown in full lines in Fig. 19. Removal of a strut from one of the partially blocked sockets 83 or 83a is accomplished by a generally reverse procedure.As shown in Fig. 31, the configuration of socket-forming recesses 150 and struts 140 advantageously are such that the center of curvature of the ribs 130, 131 is located on an axis 151 which is offset from the surface 152 of end wall 125 a distance slightly less than the offset between the axis 153, containing the center of curvature of the annular groove 147, and the end surface 154 of the strut element. As a result when the strut element is forced laterally betwenn gripping arms 126, 127 into gripped position in the recess 150, the ribs 130, 131 are in pressure contact with side portions of the annular groove, in a manner to force the strut end surface 154 into tight face-to face contact with the surface 152 of the recess end wall. By tightly holding these two surfaces in face-to-face contact, a desirable degree of additional rigidity is imparted to the assembly of the strut and connecting element.Connector elements may be formed in a wide variety of types and styles, having from one to a plurality of socket-forming recesses 150. Connector elements having more than one recess advantageously are configured so that recesses are separated angularly by 45°, or a multiple thereof, although other configurations are useable within the teachings of the invention.In Fig. 21, a single recess connector 160 is illustrated. It includes a hub section 161 defined by a cylindrical wall 162. The inside diameter of the hub cylinder is approximately the diameter of a cylindrical envelope formed by the struts 140. The diameter of that cylindrical envelope corresponds to the diameter of the cylindrical end portions 146, 148 of the struts 140, and also to the diametric dimensions of the ribs 145. A strut element thus may be freely received in the cylindrical opening 163 of the hub section 161 with a slight clearance to accommodate free rotation and free longitudinal movement of the struts within the hub cylinder. The axis 164 of the hub cylinder is disposed at right angle to the longitudinal axis 165 of the recess 150. The wall 167, which forms the end wall of the recess 150, is spaced from the hub axis 164 by a pair of space web sections 166, which are integral with the wall 167 and the hub cylinder 162.Typically, the connector elements are constructed of a predetermined, uniform thickness in the direction of the hub axis 164. Preferably, the width is approximately equal to the diameter of the cylindrical envelope of the strut elements. A thickness of approximately 6,2 mm (0.244 inch) has been found to be particularly desirable, in that it permits, in most cases, connector elements to be assembled side-by-side, cross-ways with respect to a strut, over the full length of the central body of the strut, with virtually no space left at either end. This allows structures to be formed with, in effect, a solid wall of elements joined to a transversely disposed strut across the full width of the body portion of the strut.The connector device 170 illustrated in Fig. 22 is similar to that shown in Fig. 21, but includes a pair of socket-forming recesses 150 angularly separated by 180°, with the longitudinal axis 171 of the respective socket-forming recesses 150 being coaxially aligned and intersecting with the hub axis 172. The connector element of Fig. 22 is particularly useful for joining a pair of strut elements end to end, in coaxially aligned relation, as reflected in Fig. 30. For this and other reasons, the distance d from the hub axis 172 to the outer face of the recess end wall (corresponding to the surface 152 in Fig. 31) is the same for both recesses of the connector device 170 of Fig. 22 as for the single connector 160 of Fig. 21. This geometric relationship is also applied to the several varieties of connector elements illustrated herein such that, in all cases, a strut element secured in a socket-forming recess of a connector element is positioned a fixed, predetermined distance from the central hub axis of the connector element.In the illustration of Fig. 23, a connector element 180 is shown, which also is provided with two socket-forming recesses 150. These are aligned along axes 181 intersecting with a hub axis 182 disposed at right angles thereto. The construction of the hub cylinder 185, recesses 150, etc. is generally the same as described with respect to the connector elements 160 and 170. However, in the modification of Fig. 23, the strut-receiving recesses 150 are spaced apart by an angle of 45°. In the connector elements 190 and 200 of Figs. 24 and 25, respectively, the connector elements are provided with three and four strut-receiving recesses 150, respectively, in each case arrayed along axes 191, 201 intersecting with a hub axis 192, 202 and angularly spaced 45° apart. As reflected in the views of Figs. 23 to 25, the connector elements therein shown include intermediate, radially disposed spoke-like walls 183, 193, 203 which extend radially with respect to the hub axes 182, 192, 202 and are joined integrally with end walls of adjacent recesses 150. The outermost walls 184, 194, 204, on the other hand, extend into tangency with the respective hub cylinders 185, 195, 205.In the illustrations of Figs. 26 to 28, connector elements 210, 220, 230 are formed to have, respectively, five, six and seven socket-forming recesses 150, each arrayed along an axis intersecting and extending radially from the hub axis 212, 222, or 232. The several recess axes 211, 221 and 231 are spaced apart at an angular distance of 45°, as in the case of the connectors of Figs. 23 to 25. Preferably, in each of the connector elements of Fig. 26 to 28, the exterior wall sections 214, 224, 234 are arranged to be tangent to the hub cylinders 215, 225, 235, for both esthetic and functional purposes. The wall sections 214 of the connector element 210, for example, in conjunction with the continuing wall of the associated socket-forming recess, provide a broad, flat surface on which to support the connector element and/or a flat surface to define an outer edge of a structure.The connector element 240 of Fig. 29 is substantially of the configuration shown in Fig. 1, in this instance being formed as part of a series of connector elements of common dimensions. In this respect, the distance d from the hub axis 242 to the face of any recess wall is the same uniform distance as in the other illustrated forms of connector elements.With reference to Figs. 30 and 32, the system of the invention advantageously incorporates strut elements in various graduated lengths, according to a predetermined size progression, such that strut elements of various sizes in a set may be assembled together with the before described connector elements to form a series of right triangular structural units of an assembly. In the composite illustration of Fig. 30, there are shown a series of strut elements 140a to 140f, inclusive, of progressively increasing lengths. The progression of lengths is such that when any two strut elements of a given size are joined with a connector element to form two sides of a right triangle, the strut of the next greater length is of the appropriate size to form the hypotenuse of that triangle. For example, in Fig. 32, a three-position, right angle connector element 190 is joined with two strut elements 140a of the smallest size, forming the sides of a right triangle. In the illustration, the vertically oriented strut element 140a is joined with a four-position connector element 200 and the horizontally oriented strut element 140a is joined with a five-position connector element 210. A strut element 140b, constituting the next size longer than the strut elements 140a, is joined with the connector elements 200, 210, forming the hypotenuse of a small right triangle.In the illustration of Fig. 32, the strut element 140b, which forms the hypotenuse of the first described right angular structural element 250, itself forms one side of a right triangular structural element 260 of a larger size. In this respect, the connector element 200 is joined with a second strut element 416 of the same length as the strut element 140b to form two sides of the triangle structural element 260. A second four-position connector element 200 is joined to the upper end of the upper strut element 416, and a strut element 140c, being the third element in the length progression, is joined with the upper connector element 200 and the before mentioned connector element 210 and constitutes the hypotenuse of the triangular structural element 260. As is evident in Fig. 32, a pair of the strut elements 140c may in turn constitute the sides of a still larger right triangular structural unit 270, the hypotenuse of which is constituted by the next larger size strut element 140d. Progressively larger right triangular structural units may be assembled, within the limits of the maximum length strut element provided by the set.In the system of the invention, the length progression of the strut elements is in accordance with a predetermined formula. Thus, in a system of n different lengths, each strut length is determined according to the formula: Lx = (1.414)(x-1) * Dmin - (2 * d), whereLx= Length of the xth strut of a series of 1 to n ,Dmin= the spacing between hub axes of two connector elements joined by the shortest strut element of the series,d= the distance from the hub axis to the end wall of the socket-forming section.It is known to assemble structures of right triangular units, including structures in which the hypotenuse of one triangular unit constitutes a side of a second and larger right triangular unit. In the toy system of the present invention, however, unique advantages are derived from the design of the connector elements and strut elements to accommodate lateral, snap-in assembly of the strut elements into the connectors. This enables parts to be assembled and disassembled from the structure, without involving change of the center-to-center distances between connector elements and connection points. Thus, complex, rigid, multi-dimensional structures can be designed and assembled for great facility.As shown in Fig. 30, there is also an advantageous geometric relationship between the graduated length strut elements 140a to 140f and connector elements in which there are socket-forming recesses oriented 180° apart. This includes in particular the connector element 170 (Fig. 22), which is a two-position connector element having its recesses 150 coaxially aligned and oppositely facing. This connector element serves usefully as a splicing connector, to join two shorter strut elements to form a longer strut assembly. When one of the connector elements 170 (which may conveniently be referred to as a splice connector) is joined with two struts of a given size a strut assembly is formed which is equal in length to a strut two sizes larger than the strut elements joined by the splice connector. Thus, as shown in Fig. 30, two of the shortest strut elements 140a are spliced to form a strut assembly equal in length to the strut element 140c. Two of the next size strut elements 140b are spliced to form a strut assembly equal in length to the strut element 140d. Additional corresponding assemblies are shown in the composite view of Fig. 30. It is possible, of course, to join in a splice connector element 170 strut elements of different lengths, in order to develop strut assemblies of a length different from the standard, progressive strut length illustrated in Fig. 30.Since all of the connector elements, regardless of configuration, employ a common spacing d from hub axis to the end surface of the socket-forming recess, the relationships illustrated in Fig. 30 will be true in any situation in which strut elements are assembled to a connector with a coaxial orientation.The assembly shown in Figs. 33 and 34 is comprised of a plurality of single recess connector elements 160 (Fig. 21) joined with a plurality of strut elements of a predetermined uniform size, such as elements 140c as reflected in Fig. 30. A first plurality (three in the illustration) of single unit connector elements 160 are arranged in side-by-side relation, spaced apart by the width of a connector element, and are rotatably connected to a strut element 280 in Fig. 34. The strut element 280 is passed through the hub opening 281, in which it is freely received. For purposes of identification, the reference numeral 282 is applied to connector elements of the first group. Alternating with the connector elements 282 are similar connector elements 283. The connector elements 283 are snap fitted onto the strut element 280, with the rib portions 130, 131 of the connector element tightly received in the grooves 144 of the strut element, so as to tightly grip the strut element. Thus, while the individual connector elements 282 are freely movable with respect to the strut element 200, the alternating connector elements 283 are rigidly secured thereto, both against rotation and sliding movement. A successor of such assemblies provides an articulated belt-like structure, which can be endless in form or of finite length, as desired, and can be of any suitable width for the purpose intended. As shown in Fig. 33, the end extremities of the strut elements project a short distance from each edge of the belt-like assembly.Structures of the type shown in Figs. 33, 34 have a wide variety of advantageous uses. Among these is the formation of tracks, for track-laying vehicles such as bulldozers, cranes, tanks and the like. Panel-like structures can also be assembled to function, in a toy structure, as wall or roof panels, for example, floor surfacing and the like. A narrow assembly can be utilized as a flexible cable-like element, for example.With reference now to Figs. 35 to 41, there is shown a particularly advantageous form of connector element arranged for assembly with another connector element having similar features, to provide a connector assembly providing means for joining strut elements extending in a plurality of planar directions.The connector elements 310 illustrated in Fig. 35 are formed with four recess positions 150, angularly spaced at 45°. Directly opposite one of the recess positions 150a of each element is positioned a special recess 311. The recess 311 is defined by spaced-apart side walls 312, 313 and a bottom wall 314. The side walls 312, 313 are spaced apart a distance equal to the standard thickness of a connector element and are arranged symmetrically to an imaginary plane extending through the geometric center of the connector element 310 and containing the longitudinal axis of the oppositely oriented strut-receiving recess 150a. The exposed surface of the end wall 314 lies on a plane at right angles to the previously mentioned plane, also passing through the principal axis 315 of the connector element 310.The connector elements 310 are arranged to be assembled together in the manner reflected in Figs. 35 to 37, with the respective special recess portions 311 facing each other and the principal planes of the respective connector elements being oriented at right angles. The respective connector elements 310 are pressed together until the end walls 314 of the recesses 311 are in firm face-to-face contact, so that the respective central axes 315 of each element lie substantially in a common plane.Desirably, each of the recess walls 312, 313 is formed with a transverse groove 316 arranged to receive, in detent locking relation, ribs 317 projecting from opposite sides of spoke walls 319. Accordingly, when the two elements are assembled together, they are relatively rigidly locked together against any but intentional separation.As reflected in Fig. 36, when the walls 312, 313 first engage the projecting ribs 317, the walls are displaced outwardly. The presence of a small gap 318 enables the gripping arms of the opposed strut-receiving recess 150a to be easily displaced toward each other while the walls 312, 313 are being outwardly displaced by the ribs 317. When the parts are pressed together to their final positions, with the end walls 314 seated against each other, each of the sets of ribs 317 will be seated in each of the sets of grooves 316, substantially as shown in Fig. 37.The assembled connector elements of Figs. 35 to 39 provide for the support of strut elements in each of two planar directions disposed at right angles. The connector arrangement thus is perfectly suited for assembling external corners of structures, as can be appreciated by observations of Figs. 38 and 39.In the composite view of Fig. 40, a connector element 310 of the type shown in Figs. 35 to 39 is arranged to be joined with a second, seven-position connector element 410. The connector element 410 includes a special recess 411 disposed coaxially opposite to a strut-receiving recess 150a.Assembly of the connector elements 310, 410, to form a multi-planar assembly is accomplished in the same manner described with respect to Figs. 35 to 39. The resulting assembly is of T-shaped configuration when viewed from above, as reflected in Fig. 41, and provides for the mounting of strut elements in each of three planar directions. In the T-shaped assembly of Figs. 40, 41, the upper socket recess 150a is not accessible for normal, lateral snap-in assembly of a strut element, because of the presence of the associated connector element. However, by providing the gap 318 in the recess end wall, it becomes possible to insert the strut initially at an angle and to install it by a twisting motion, all as hereinbefore described. The gap 318 allows the gripping arms 126, 127 to more easily separate, in order to accommodate a twist-in assembly of the strut.For certain applications, however, it may be desired to lock a connector element together with a strut passing through its central hub opening, for rotation in unison and/or for fixing the position of the connector element axially along the strut element. To this end, the system includes a drive element, such as illustrated in Figs. 42 to 44 of the drawing, for frictionally and non-rotatably gripping a strut element. In the illustrated form, the drive element comprises a drive block 510, injection molded of suitable plastic material and advantageously incorporating a socket-forming recess 150 of the form previously described. This includes particularly the opposed projecting ribs 130, 131 defining a narrow throat area between the gripping arms 126, 127, Adjacent the closed end of the recess 150, the block 510 advantageously mounts a driving lug 511 projecting laterally from one end face 512, generally parallel to the alignment of the ribs 130, 131.In a typical utilization of the drive block 510, a connecting element 240, typically of a full snowflake configuration, having eight strut-receiving positions, is mounted on a strut 513. The drive block 510 is applied to the body portion of the strut 513, so that the respective ribs 130, 131 are received in and lockingly engaged with opposed longitudinal grooves 144 of the strut. The block 510 is thus rigidly fixed to the strut against rotation and also is frictionally restrained against longitudinal movement along the strut (being slidable therealong, however, under appropriate force).The location of the drive lug 511 is such that, when the connector element 240 and drive block 510 are directly adjacent each other, the drive lug 511 is positioned in and substantially occupies the trapezoidal space between a pair of adjacent, radially disposed spoke-like walls 123. The strut 513 and connector element 240 are thus locked against relative rotation, so that rotational drive applied to one of the elements is correspondingly imparted to the other. By positioning drive blocks 510 on opposite sides of a connector element, the connector element can be locked in position, axially on a strut.For many dynamic toy assemblies, drive pulleys and/or wheels are useful and desirable elements. To advantage, a combined pulley/wheel element 610 is shown in Fig. 45. This is an injection molded part formed with an outer rim 611 and a central hub opening 612 adapted to be closely received over a strut element. Radially outward from the central opening 612 are one or more drive recesses 613. These are arranged to receive the drive lug 511 of a drive block (Fig. 42). As shown in Fig. 47, the element 610 is provided with an external annular recess 614, which enables the element to function as a pulley, when associated with an appropriate drive belt (not shown). When the element 610 functions as a pulley, it is drivingly connected to a strut element, using a drive block 510, functioning either as a drive pulley or a driven pulley, as the case may be.The element 610 can be covered to form a wheel by applying the tire element of Fig. 46. The tire element 620 is formed of a resilient elastomer, such as neoprene. The inner portion 621 of the tire is of a width to be closely received in the annular recess 614. The outer portion 622 of the tire is wider than the inner portion 621, advantageously equal in width to the thickness of the outer rim portion 611 of the wheel element 610. Shoulders 623 are formed at each side of the tire. These engage outer flanges 624 of the wheel element 610, to position the tire concentrically on the supporting rim.When used as a wheel, the element 610 may be driven or not, as desired. If it is to be driven, then a drive block 510 is employed, as previously described.The construction toy system of the invention provides a uniquely simplified, yet exceptionally versatile construction medium, for assembling a limitless variety of structures, both static and dynamic in character. The system easily lends itself to the production, by economical, mass production injection molding techniques of standardized building elements of a wide variety, permitting the relatively quick and simplified assembly of structures.Within the basic concepts of the invention, it is possible to construct simplified and effective forms of dynamic structures, such as endless tracks or belts, driven rotating systems and the like. These are achieved with the consistent use of standardized strut elements and standardized connecting elements. That is, the connecting elements utilize standardized socket-forming recesses, although various in number, and such recesses are located at standardized distances from the principal axis of the connecting element. Likewise, the strut elements incorporate standard end configurations, in conjunction with body portions of various length. Further, by providing for a splice connector, capable of joining two strut elements end to end, the structural combinations available from a relatively limited number of standardized strut lengths is multiplied.The elements of the construction toy of the invention are adapted readily for high production injection molding of the component parts of a suitable plastic material. A variety of such plastic materials are suitable for the purpose, it being necessary, of course, to select a material having a reasonable degree of strength and elasticity to enable proper functioning of the gripping arms, for example, over numerous assembly and disassembly operations. A material known to be suitable for the purpose is Celcon M270 , an acetal copolymer made available by Hoechst Celanese, Chatham, New Jersey, USA.By enabling the hub-like connector elements to be joined with structural elements by a lateral snap-together action, it becomes more practical to assemble large and complex structures, because the center-to-center distance between component elements does not have to be altered during joining of the components. By contrast, where assembly of the components requires axial insertion of one part into another, center-to-center distances are temporarily enlarged, which at best requires great care and at worst may make it impossible to assemble certain types of structures.The arrangement of the invention provides a unique two-way gripping action between the hub-like connector elements and the structural elements, wherein the outer, deflectable portions of the gripping arms provide lateral containment, while the innermost portions of the gripping arms form a relatively non-deflectable flange-receiving cavity which freely admits the end flange 86 of the structural element during lateral assembly, but provides positive restraint against axial movement of the structural element. | Construction toy system, comprising connector elements (10) and strut-like structural elements (13) adapted to be removably engaged with its ends in lateral and laterally open sockets (14) of such connector elements (10) to form a composite structure, said sockets (14) each having an inner end wall (15) and a pair of spaced-apart gripping arms (16) defining an axis (19) of said socket extending between said gripping arms, integral locking projections (24) extending inward from at least one of said gripping arms (16), said locking projections (24) being spaced from said inner end wall (15) and defining with said innner end wall (15) a first locking chamber, said gripping arms (16) being formed with concave grooves (18) therein, an opposed pair of said grooves (18) defining a second locking chamber, at least one end portion of said structural elements (13) being shaped to be confined within a generally cylindrical envelope, said end portion defining an axis of said structural element (13) and having a locking flange (26) receivable laterally within said first locking chamber and being locked therewith against movement in the direction of the axis of the structural element (13),characterized in that, each connector element (10) has more than one of said sockets (14), that the concave grooves (18) of the gripping arms (16) of each socket extend from said locking projection (24) toward the ends of each gripping arm of said socket (14), that said locking flange (26) is arranged at the end extremity of said structural element (13), that each end portion of the structural element (13) has a circumferential groove (27) immediately adjacent and partly defining said locking flange (26), that said annual groove (27) is adapted to receive said locking projections (24) when said structural element (13) is inserted laterally into said open ended socket (14), that said concave groove (27) is shaped in a position to cloesely receive portions of the cylindrical envelope of the structural element (13), and that said gripping arms (16) are elastically deflectable to accomodate lateral insertion of said structural element (13) into said socket (14).Toy systems according to claim 1, characterized in that the structural elements (13) have a generally circular cross section in the region of the end extremities thereof, that the spacing between pairs of gripping arms is less than the diameter of said circular cross section, and that the contours of the concave recesses (18) of said gripping arms correspond generally to the circular contours (28) of said structural elements.Toy systems according to claim 1 or 2, characterized in that the inner end wall (15) of each socket-forming section (14) extends between the gripping arms (16) of each pair at their inner ends and define with said gripping arms a generally U-shaped socket for the lateral reception of an end portion of a structural element (13), the cross section configuration of said socket, taken along its longitudinal axis (19), and in a plane bisecting said gripping arms (16), being generally in close confirmity to the longitudinal cross sectional configuration of an end portion of one of said structural elements (13).Toy system according to one of claims 1 to 3, characterized in that said locking projection means (24) is of arcuate convex configuration and extends generally from one edge of a gripping arm (16) to the other, the annular groove (27) in said structural element having a cross sectional configuration to closely receive said locking projections (24), whereby said structural element (13) is locked against separation from said connector element in the direction of the axis of said structural element.Toy system according to one of claims 1 to 4, characterized in that said structural elements (13) are of generally circular cross section over at least a portion of their length, that said structural elements are of generally X cross section, within the envelope of said generally circular cross section, over at least a portion of their length, said portions of generally X cross section being receivable in the space between a pair of said gripping arms (16) while said structural elements (13) are disposed at right angels to the axis (19) defined by said gripping arms, and that said structural element (13) is adapted to be forced laterally between a pair of opposed locking projections (24) on said gripping arms (16) and being thereby lockingly gripped by said projections.Toy system according to one of claims 1 to 5, characterized in that opposed locking projections (130, 131) on said gripping arms (126, 127) extend transversely thereto and extend into the space between said gripping arms, that said strut-like structural element (13) has an end flange defined in part by said annular groove (147) and a flat end face (154) spaced from said groove, and that said annular groove (147) and said locking projections (130, 131), and said end wall (152) and said flat end face (154), are so geometrically related that, when said structural element is assembled in said recess, the flat end face of said structural element is urged firmly and resiliently in an axial direction into face to face contact with said end wall (152).Toy system according to one of claims 1 to 6, characterized in that said connector element comprises a first connector element (70) and has a central core (71) defining a central axis of said connector element, a plurality of sockets (82) arranged generally radially about said core for receiving structural elements, said core and sockets forming said first connector element to be of generally flat configuration and of predetermined thickness, and an open-sided recess (74) in one side of said first connector element, extending to said central axis and having a width to the thickness of the connector element, said open-sided recess (74) being adapted to receive a second connector element (70a) to form a composite connector element having sockets radiating in two planes.Toy system according to claim 7, characterized in that the first connector (70) has a socket (83) for receiving a strut-like structural element (90) directly opposite said open sided recess, whereby, in an assembly of first and second joined connector elements (70, 70a), the second connector element (70a) has a socket for receiving a strut-like structural element at the location of the open-sided recess in the first connector element (70). Toy system according to claim 7 or 8, characterized in that the open-sided recess (74) is defined by a pair of spaced-apart, parallel guide walls (72, 73) for receiving the second connector element (70a), said guide walls having detent means (97) therein cooperating with detent means (98) on the second connector element (70a) to retain an assembled pair of first and second connector elements in joined relation.Toy system according to one of claims 7 to 9, characterized in that said first connector element (70) has a plurality of sockets (82, 83), each comprised of a pair of gripping arms and an end wall, the end walls (79, 80) of adjacent sockets being adjacent and integrally joined, and that at least one of said end walls (80) is slotted to form a gap (81), to accomodate outward deflection of said guide walls (72, 73).Toy system according to one of claims 7 to 10, characterized in that said first connector element has a socket (83) for receiving a structural element located directily opposite said open-sided recess, and that said this socket (83) has the slotted end wall (80).Toy system according to one of claims 5 to 11, characterized in that said sockets (82, 83) are configured for lateral, snap-in reception of end portions of said structural elements (90), and that the gripping arms of said last mentioned socket (83) is separable upon displacement of the parts of said slotted end wall (80), to accommodate assembly of a structural element (90) by other than lateral, snap-in reception.Toy system according to one of claims 7 to 12, characterized in that said open sided recess (74) has detent means (97) of a first type therein, and that portions of said first connector element (70) located diametrically opposite said open sided recess are formed with detent means (98) of a second type engageable with detent means (97) of said first type for lockingly engaging a pair of connector elements (70, 70a) in assembled relation.Toy system according to one of claims 7 to 13, characterized in that said first connector element (310) has a plurality of sockets (150, 150a), each comprised of a pair of gripping arms and an end wall, that the end walls of adjacent sockets are adjacent and integrally joined, that at least one of said sockets (150a) is arranged directly opposite to said open-sided recess (311), and that the balance of said sockets (150) being arrayed on the same side of plane containing said open-sided recess (311) and said one socket (150a), whereby, when said first connector element is joined with a second connector element (310), said second connector element has a plane containing the axes of its sockets, the sockets of the first connector element project in the plane of and/or one side of the plane of the second connector element.Toy system according to claim 14, characterized in that the first connector element is configured with one socket (150a) directly opposite to said open-sided recess (312) and all other sockets (150) are on one side of a plane containing said one socket (150a) and said recess (311) and are disposed at right angles to said plane containing the open-sided recess (311) and at least one socket (150a) of said first connector element.Toy system according to claim 15, characterized in that said second connector element is configured the same as the first connector element, whereby a connected pair of said connector elements define a right angle corner structure.Toy system according to claim 15, characterized in that said second connector element (410) is configured with sockets (150, 150a) extending in an array of greater than 180, whereby a connected pair of said first and second connector elements (310, 410) define a Tee-shaped joint structure.Construction toy system, comprising connector elements (10) and strut-like structure elements (13) removably joinable with other elements to form a coherent structure, wherein at least certain of the connector elements (10) comprise a common portion and a plurality of socket-forming sections (14) extending generally radially outward from said common portion, each said socket-forming section being disposed on a predetermined socket axis (19) extending generally radially from said common portion, each said socket-forming section comprising a pair of spaced-apart, generally parallel cantilever mounted gripping arms (16) symmetrically arranged with respect to its said socket axis, each pair of gripping arms (16) defining between them an open-sided, axially disposed socket (14), said strut-like structural elements (13) being formed with opposite end portions and intermediate portions integrally joining said end portions,characterized in that, the gripping arms (16) are formed with first interlock means (18) to interlock with a strut-like structural element (13) for releasably but firmly holding a strut element aligned with said socket axis, second interlock means (24) are formed in said socket-forming section to interlock with a strut-like structural element (13) simultaneously engaged by the first interlock means (18) for releasably but firmly holding the strut-like structural element (13) in a predetermined axial position along said socket axis, the opposite end portions being provided with first and second interlocking means (28, 27) for simultaneous cooperative engagement with the first and second interlocking means (18, 24) of a socket-forming section of a connector element, whereby the respective first interlocking means (18, 28) hold a structural element in coaxial alignment with a selected socket axis while the respective second interlocking means (24, 27) hold said structural element in predetermined axial position on said selected socket axis, said arms (16) being resiliently separable to accommodate lateral snap-in reception of an end portion of a strut-like element (13) in a direction transverse to the socket axis (19), whereby the structural element is firmly spaced and positioned in fixed relation to the socket-forming section.Toy system according to claim 18, characterized in that the second interlocking means comprise opposed rib-like elements (24) on the spaced-apart gripping arms (16) and conforming groove means (27) on the opposite end portions of the strut-like structural elements (13), the rib-like elements (24) being oriented transversely to the socket axis (19) to receive the conforming groove means (27) during lateral reception of an end portion between a pair of gripping arms (16).Toy system according to claim 18 or 19, characterized in that the socket-forming section includes an end wall (154) integral with the gripping arms and spaced from the rib-like elements (130), the strut-like structural elements (140) having end surfaces spaced from said conforming groove means (147), the spacing between the rib-like elements (330) and the end wall (154) being such, in relation to the spacing between the conforming groove means (147) and the end surface (152), that the end wall (154) and the end surface (152) are urged into snug contact when a strut-like structural element (13) is received in the socket-forming section.Toy system according to claim 18, characterized in that the second interlocking means comprise a rib-like interlocking means (24) on one of the socket-forming section (14) or the strut-like structural element (13), and conforming groove means (27) on the other of said section or element.Toy system according to claim 21, characterized in that the socket-forming section has a closed end formed by an end wall (152) and that the structural element has an end surface (154), the second interlock means yieldably urging the end surface into snug contact with the end wall.Toy system according to claim 18, characterized in that the commong portion of the connector element (160) includes a hub-forming section (161) having a transverse opening (163) therein of a size and shape for the axial reception of a strut-like structural element and defining a hub axis (164), the hub axis being disposed at rigth angles to and substantially intersecting with said socket axis (164), and the connector element (160) comprises a single socket-forming section (150) integrally associated with a single hub-forming section (161).Toy system according to claim 16, characterized in that the connector element (170) comprises a pair of socket-forming sections (150) integrally associated with a single hub-forming section, the socket-forming sections being oppositely disposed and being aligned along a common socket axis (171).Toy system according to claim 18, characterized in that the connector element comprises a plurality of n socket-forming sections, each of said socket-forming sections being aligned along respective socket axes disposed approximately 45° with respect to a neighboring socket axis and all of said axes intersecting each other substantially at said hub axis, wherein n is an integer between 2 and 8.Toy system according to one of claims 23, 24 or 25, characterized in that each of said socket-forming sections being disposed at a fixed predetermined distance (d) from the hub axis, whereby, when a strut-like structural element (13) is retained in any socket-forming section, the end extremity of the structural element is spaced a fixed, uniform distance from the hub axis.Toy system according to one of claims 18 to 26, characterized in that it includes a series of strut-like structural elements of graduated lengths, wherein in a system of n different lengths of said structural elements, each length is determined according to the formula Lx = (1.414) (x-1) * Dmin - (2 * d), where Lx = Length of the xth structural element of a series 1 to n , D min = the spacing between hub axes of two connector elements joined by the shortest structural element of the series, and d = the distance from the hub axis to the end wall of the socket-forming section, a plurality of connector elements and strut-like structural elements of said system being adapted to be assembled into one or more right triangles (250, 260, 270).Toy system according to claim 27, characterized in that an assembly comprising a connector element (170) of claim 7, joined with two structural elements (140b) of length lx in a series, is equal in length to a structural element (140d) of length L(x+2) in said series.Toy system according to claim 18, characterized in that the gripping arms (16) are formed with rib-like projections (24) extending transverse with respect to the socket axis (19) and project inward toward the socket axis, the strut-like structural element (13) being formed, in a predetermined area between its ends, with opposed longitudinally extending grooves (39), the strut-like structural element (13) being yieldably received in the socket (14) in an orientation disposed at 90° to the socket axis (19), with said rib-like projections (24) being received in an opposed pair of said grooves (39), whereby the strut-like structural element (13) is non-rotatably gripped by the connector element with the structural element disposed perpendicular to the socket axis (19).Toy system according to claim 29, characterized in that the common portion of the connector element includes a hub-forming section (161) having a transverse opening (163) therein of a size and shape for the axial reception of a strut-like structural element and defining a hub axis (164), the hub axis being disposed at right angles to and substantially intersecting with the socket axis (165), wherein a plurality of such connector elements are joined to form a belt-like structure, a first group (282) of such connector elements being arranged in side-by-side relation, spaced apart by a distance at least equal to the width of a connector element, the hub axes of each of the elements of said first group being coaxially aligned, a first strut-like structural element (280) extending through the hubs of each of the connector elements of said first group, a second group (283) of such connector elements (160) being arranged in side-by side relation, and interspersed in the spaces between connector elements of the first group (282), the connector elements of the second group (283) gripping said first strut-like structural element (280) by engagement of the rib-like projections (130, 131) of the connector elements with an opposed pair of longitudinal grooves (144) of said first structural element, and additional groups (282, 283) of such connector elements and strut-like structural elements are connected in an extended series to form an articulated belt-like structure.Toy system according to claim 30, characterized in that the strut-like structural elements (280) are of such length, in relation to the combined width of the first and the second groups (282, 283) of connector elements, that end portions of the structural elements project laterally from each side of the assembly.Toy system according to claim 29, characterized in that the connector element (510) comprises an integral formed, laterally extending drive lug (511), the connector element being mounted on a strut-like structural element (513) with the rib-like projections (130, 131) of the connector element being received in opposed longitudinal grooves (144) of the structural element, whereby the connector element is locked in fixed relation to the structural element with the structural element at right angles to the socket axis, and that an additional element (240) is mounted on the structural element, the additional element being positioned adjacent to the connector element, the drive lug (511) being in driving engagement with an adjacent portion of the additional element.Toy system according to claim 32, characterized in that the additional element comprises a circular wheel-like element (610) having a rim portion (611) and a hub portion, the hub portion having a hub opening (612) for receiving the strut element, that the wheel-like element has a drive opening (613) located a predetermined distance radially outward from the center of the hub portion, for the reception of the drive lug (511) of the connector element, and that the wheel-like element has an outwardly facing circumferential groove (614) in its rim portion.Toy system according to claim 33, characterized in that an annular tire-like element (620) formed of elatomeric material is removably received in the annular groove (614). | CONNECTOR SET LP; CONNECTOR SET LIMITED PARTNERSHIP | GLICKMAN JOEL I; GLICKMAN, JOEL I. |
EP-0490037-B2 | 490,037 | EP | B2 | EN | 20,011,114 | 1,992 | 20,100,220 | new | B01J20 | null | B01J20 | B01J 20/18D | Method of cleaning waste gas containing ketonic organic solvents | An adsorbent comprising zeolite with an amount of solid acid of not more than 0.05 mmol/g as determined by pyridine temperature programed desorption method and with a SiO₂/Al₂O₃ molar ratio of not less than 50, and a cleaning method of waste gas containing ketonic organic solvents are disclosed. | The present invention relates to a method of cleaning waste gas containing ketonic organic solvents using a specific adsorbent.So far, for the deaning of gas containing solvents, activated carbon has been used extensively as an adsorbent. When ketonic organic solvents are contained in gas, however, the formation of very small amount of decomposition products is often identified due to the catalytic action of activated carbon. Among these decomposition products, easily desorptive ones can cause a decrease in purity of recovered solvent and hardly desorptive ones can contaminate the activated carbon, both resulting in the obstacle for adsorption. Moreover, the decomposition products are most often acids, which adversely affect on the corrosion of the material of device.Ketones produce carboxylic acids via enol intermediates due to the oxidative action on the surface of adsorbent. Because of the generation of heat, this reaction progresses abruptly and the heat of reaction generated is accumulated. When sufficient oxygen is supplied, a chain reaction is triggered and the bed of activated carbon itself sometimes catches fire. The firing temperature of fresh activated carbon is around 400 to 500 °C, but, if large amounts of high-boiling point substances are accumulated, it may sometimes decrease to lower than 200 °C.As described, the use of activated carbon for the cleaning of gas containing ketonic organic solvents indudes various problems. For this reason, contrivances have been made in such ways that an activated carbon with low catalytic activity is used, that a damping device is installed in the upstream area of adsorption bed to prevent the temperature rise of bed due to the heat of adsorption, heat of reaction, etc., and the like. However, as long as the activated carbon is used as an adsorbent, more or less catalytic action to ketonic organic solvents is inevitable. When installing the damping device, the inhibition of catalytic action will become possible, but, if the relative humidity becomes high, the adsorption level of activated carbon to organic solvents will be decreased. Thus, the greatest care was required for the running and the management of adsorption device.Moreover, recently, zeolites with increased hydrophobicity also begin to be used for the adsorption of organic compounds as new adsorbents in place of activated carbon (WO 84/04913 and US Pat. 4795482).However, when the inventors tried the adsorption of ketonic organic solvents with these hyrophobic zeolites, it was found that they exhibited the catalytic activity similarly to activated carbon. Namely, while it is possible to adsorb the ketonic organic solvents by treating waste gas containing ketonic organic solvents with activated carbon, conventional hydrophobic zeolites or the like, the ketonic organic solvents cause the decomposition or the polymerization reaction on adsorbent in the process of the regeneration of adsorbent under heat due to the catalytic action thereof. As a result, the purity of ketonic organic solvents in recovered organic solvent was low, not permitting the reuse thereof. Moreover, during repeating the adsorption and desorption procedures, the adsorption performance of adsorbent itself was also decreased and not only stabilized deaning of waste gas was impossible, but also problems from the points of safety and maintenance such as firing and corrosion of device were presentPaying attention particularly to the catalytic action of adsorbent to ketonic organic solvents, the inventors made diligent investigations to provide an adsorbent which enables the recovery of high-purity ketonic organic solvents from waste gas without special procedures and further which is not in danger of firing and decreased adsorption performance and does not exhibit the catalytic property to ketonic organic solvents.The invention provides a method as defined in claim 1 using an adsorbent comprising zeolite with an amount of solid acid of not more than 0.05 mmol/g as determined by pyridine temperature programed desorption method and with a SiO2/Al2O3 molar ratio of not less than 50.In following, details of the invention will be illustrated.The SiO2/Al2O3 molar ratio of A type zeolites, X type zeolites, Y type zeolites, etc. used commonly as general purpose adsorbents is as low as 2 to 5 and these zeolites adsorb water more selectively than organic compounds. Hence, they are not suitable as the adsorbents for deaning waste gas containing organic solvents.Zeolites lose the hydrophilic characteristic at a SiO2/Al2O3 molar ratio of more than 20 and become gradually to exhibit the hydrophobic characteristic. The zeolites showing the hydrophobicity in this way are useful for the cleaning of waste gas containing organic solvents as hydrophobic adsorbents similarly to activated carbon. The hydrophobic zeolites known hitherto, however, possess simultaneously the catalytic action. Hence, when they are contacted with highly reactive organic compounds such as ketonic organic solvents, the ketonic organic solvents adsorbed cause the decomposition or the polymerization reaction in the process of the regeneration under heat due to the catalytic action of zeolites. Further, during using them as adsorbents for a long term, the remaining ketonic organic solvents become low-polymerization products or decomposition products to cause the firing, decreased adsorption performance, corrosion of device, etc. Such catalytic reaction takes place particularly violently In the desorption procedure where the regeneration is performed by heating and progresses, through slight, even in the PSA (pressure swing adsorption) procedure at low temperature. Further, because the decomposition reaction of ketonic organic solvents is an exothermic reaction, the heat of reaction is accumulated In the bed of adsorbent even in the case of PSA process not accompanying the regeneration under heat, sometimes leading to an abrupt increase in the temperature of adsorbent.The active sites of this catalytic reaction are considered to be the acid sites in the crystal of hydrophobic zeolite. Thus, the zeolite with Infinite SiO2/Al2O3 molar ratio is considered to have no catalytic action. However, the limit of SiO2/Al2O3 molar ratio of zeolites practically available or adjustable is around 500. This is due to that aluminum oxide is contained in the source of silicon available as a raw material of zeolites, though in very small amount. For example, in the case of direct synthetic method, very small amount of aluminum atoms in the source of silicon is selectively taken into the skeleton of zeolite crystal in the process of the crystallization. Moreover, it is practically impossible to completely remove the very small amount of aluminum atoms in zeolite seven by the dealumination treatment with mineral acids etc.Based on this reason, zeolites showing hydrophobicity has been difficult hitherto to be used as adsorbents for waste gas containing highly reactive ketonic organic solvents due to the catalytic action thereof.The skeleton of zeolite crystal is, however, formed with SiO4 and AlO4 and incombustible. For this reason, the adsorbent itself never combusts in the case of the cleaning of waste gas containing combustible substances such as organic solvents, which is very advantageous in the aspect of safety.The inventors made diligent investigations to obtain a zeolite adsorbent without the catalytic activity to ketonic organic solvents preparing various zeolites by direct synthetic method or methods of giving modification treatment to synthetic zeolites. As a result, it has been found that, if the amount of solid acid is not more than 0.05 mmol/g, the zeolite does not exhibit the catalytic activity to ketonic organic solvents and, if the SiO2/Al2O3 molar ratio is not less than 50, it is hydrophobic and well adsorbs the ketonic organic solvents even under the coexistence of moisture.As described later, the adsorbent used in the method of the invention can be obtained by the hydrothermal calcination of zeolite with desired SiO2/Al2O3 molar ratio or by converting it to alkalimetal type or alkaline earth metal type.In the case of the SiO2/Al2O3 molar ratio being under 50, it is difficult to make the amount of solid acid not more than 0.05 mmol/g even by said hydrothermal treatment, while, even if converting to alkali metal type or alkaline earth metal type, the hydrophobicity is decreased and the zeolite becomes to adsorb moisture in large amounts, thus it is not suitable as an adsorbent used in the method of the invention. For this reason, the SiO2/Al2O3 molar ratio must be not less than 50.Moreover, as well-known, zeolites have the molecular sieve effect and the type of adsorbable molecules is determined depending on the type of zeolites. Also, in the case of recovering ketonic organic solvents from waste gas, it is only necessary to select the zeolites having larger pore sizes than the diameter of ketone molecules to be adsorbed. Usually, such pore sizes may be realized with zeolites having 8-, 10- or 12-membered oxygen ring, and the crystal structures of chabazite, offretite, mordenite, faujasite ,Ω, ZSM-5 and ZSM-11 type, etc. are suitable.The preparation methods of hydrophobic zeolites with high SiO2/Al2O3 molar ratio indude a method of preparing by dealumination treatment etc. with mineral adds etc. using natural zeolites or synthetic zeolites as starting raw materials, or a direct synthetic method by mixing silica source, alumina source, alkali source and organic bases for crystallization.As the hydrophobic zeolites prepared by dealumination treatment etc., dealuminated mordenite (N.Y. Chen, J. Phy. Chem., 80, (1), 60-64 (1976)), ultrahydrophobic Y type zeolite (GB PaL 2014970, Studies in Surface Science and Catalysis, Volume 5, 203-210 (1980)), hydrophobic L type zeolite (Eur. Pat. 258127), etc. are known.As the hydrophobic zeolites prepared by direct synthetic method, ZSM-5 (US PaL 3702886), ZSM-11 (US Pat. 3709979), ZSM-12 (US Pat. 3832449), ZSM-22 (US PAT. 4556477), ZSM-23 (US Pat. 4076842), ZSM-48 (Eur. Pat. 23089), Silicalite (US Pat. 4061724), etc. are known.All of these can be suitably used for the production of the adsorbents, but the SiO2/Al2O3 molar ratio of zeolites to be obtained must be not less than 50 as described previously.Usually, the hydrophobic zeolites obtainable by above-mentioned methods are proton type. In order to convert these to zeolites with an amount of solid add of not more than 0.05 mmol/g as determined by pyridine temperature programed desorption method, a method of extinguishing the active sites In the crystal skeleton of proton type hydrophobic zeolites by hydrothermal calcination treatment, a method of converting to alkali metal type or alkaline earth metal type by neutralization method or ion-exchange method, and the like can be selected suitably. The conditions of hydrothermal calcination treatment for making the amount by solid add not more than 0.05 mmol/g differ depending on the structure of zeolites and the SiO2/Al2O3 molar ratio, but, by contriving the conditions as below, aimed adsorbents can be obtained regardless of the structure of zeolites, if the SiO2/Al2O3 molar ratio Is not less than 50.The concentration of steam in hydrothermal calcination treatment is preferable to be not less than 2 vol. % and the concentration of steam of 5 vol. % or more is a practical condition. When the concentration of steam is high, the adsorbents can be obtained even under conditions of calcination temperature being relatively mild. Through the hydrothermal calcination at a temperature under 500 °C, however, it is difficult to completely extinguish the catalytic activity of adsorbent to ketonic organic solvents. Also, if over 1200 °C, the crystal structure itself of hydrophobic zeolites tends to collapse. That is, the preferable temperature range for performing the hydrothermal calcination is 500 to 1200 °C, preferably 600 to 1000 °C. The time for the hydrothermal calcination treatment differs depending on the concentration of steam and calcination temperature, but more than 30 minutes are required within a said temperature range. When converting to alkali metal type or alkaline earth metal type, it is only necessary to replace protons with ions such as Li, Na, K, Cs, Be, Mg, Ca, Sr and Ba by neutralization method or ion-exchange method. Alkali metal type or alkaline earth metal type zeolites are unsuitable for the adsorbents, because the hydrophobicity decreases at the SiO2/Al2O3 molar ratio of under 50 to adsorb moisture in large amounts. Moreover, in such case that the SiO2/Al2O3 molar ratio is under 200 and the cationic ions are of alkaline earth metal with bivalence, local imbalance of charges in often caused in zeolite. Namely, when the SiO2/Al2O3 molar ratio is under 200, the alkali metal type with monovalence such as Li, Na, K or Cs is more preferable because of lack of the catalytic activity to ketonic organic solvents.As the methods of converting powder of proton type hydrophobic zeolites to alkali metal type or alkaline earch metal type, there are neutralization method, ion-exchange method, combined method of both, etc. The neutralization method is a method wherein an aqueous solution of hydroxide of alkali metal or alkaline earth metal is slowly added dropwise to the slurrried proton type hydrophobic zeolite to neutralize the sites of solid acid of zeolite, thus converting to alkali metal type or alkaline earth metal type. The ion-exchange method is a method wherein proton type hydrophobic zeolite is immersed into an aqueous solution of salt of alkali metal or alkaline earth metal to exchange ions at a temperature of ambient temperature to 100 °C, thus converting to alkali metal type or alkaline earch metal type. In the case of ion-exchange method, when reaching the exchange equilibrium, the ion-exchange does not progress further and perfect alkali metal type or alkaline earch metal type cannot be achieved only by one time ion-exchange, hence further several times ion-exchanges should be repeated. Moreover, the combined method of both is a method wherein hydrophobic zeolite is made into slurry with an aqueous solution of salt of alkali metal or alkaline earth metal and neutralized with an aqueous solution of hydroxide of alkali metal or alkaline earth metal for preparation.According to this combined method, perfect alkali metal type hydrophobic zeolites can be obtained and the procedure is also simple, thus this is the most rational method. However, even if any method may be used for preparation, the hydrophobic zeolites can be used suitably as the adsorbents, provided they are of perfect alkali metal type or alkaline earth metal-type. The alkali metal type or alkaline earth metal type hydrophobic zeolites thus obtained are further washed sufficiently and dried. If the washing procedure is not enough, the adsorption performance sometimes decreases due to the alkali metal salt adhered thereto.As a measurement method of acidic property of zeolites, there is relatively simple temperature programed desorption method (TPD method). In the TPD method, basic substance (usually, thermally stable ammonia, pyridine, etc. are used) is adsorbed onto the sample, and then this is desorbed at a constant velocity while raising temperature. At this time, since the adsorption of basic substance onto the acid sites is considered to be 1:1 based on the acid-base reaction, the amount of basic substance desorbed can be regarded as an amount of add sites. Moreover, since the basic substance adsorbed onto stronger acid sites is considered not to be eliminated until higher temperature, the desorbed temperature indicates the strength of add sites. In this way, by the TPD method, the amount of acid and the strength of add can be known simultaneously. The TPD method with pyridine (Py-TPD method) may be conducted along following procedure using a flow type TPD device. Namely, the sample is packed Into the adsorption tube under the conditions below and vacuum exhaustion is conducted as a pretreatment. Pyridine is adsorbed onto the sample and, successively, temperature is raised at a constant velocity while following He as a carrier gas to deaerate the gas phase and pyridine phisically adsorbed to observe the desorption spectrum. Sample0.4 g Pretreatment 500 °C, vacuum exhaustion for 1 hour Adsorptionroom temperature. 15 minutes, 50-60 TorrDeaeration100 °C, vacuum exhaustion for 5 minutesDesorptionflow of He 60 cc/min temperature-raising velocity 10 °C/minWith zeolite adsorbents, when the amount of solid add by this Py-TPD is higher than 0.05 mmol/g, the decomposition occurs on desorption because of many add sites being main active sites, resulting In the decreased purity of organic solvent recovered. In other words, the catalytic property to ketonic organic solvents is too high, which is unpreferable. If not more than 0.05 mmol/g, the acid sites being active sites become less and the decomposition becomes hard to occur an desorption permitting the recovery of organic solvents with high purity. In other words, if the amount of solid acid is made not more than 0.05 mmol/g, the ketonic organic solvents do not cause the decomposition or the polymerization reaction on adsorbent due to the catalytic action thereof making it possible to recover and to reuse the ketonic organic solvents with high purity.The adsorbents are usually used in a shape of cylinder, sphere or honeycomb. For converting the powder of zeolites to these shapes, inorganic binder components such as silica sol, silica gel and day minerals are added to increase the bondability between carrier and zeolite crystals or zeolite crystals each other because zeolite crystal itself has no bondability, followed by secondary processings such as molding and honeycombing. The binder component is preferable to be inert and ones showing the reaction activity to ketonic organic solvents such as alumina sol and alumina gel are unsuitable. Moreover, after the molding or honeycombing, the calcination treatment is required to retain the shape of these secondary processed products. At this time, if the calcination procedure is performed under the hydrothermal conditions, it is not needed to hydrothermally calcine the powder of zeolites beforehand. Namely, as a rational implementing method of obtaining the inventive adsorbents by the hydrothermal calcination treatment, a method of first performing the secondary processing of the powder of hydrophobic zeolites, then successively performing the hydrothermal calcination is possible. Of course, the powder of zeolites after the hydrothermal calcination may be secondarily processed and then calcined under mild conditions. When the proton type zeolites are converted to alkali metal type or alkaline earth metal type by the neutralization method, ion-exchange method or combined method thereof, washing and drying are accompanied. If converting to alkali metal type or alkaline earth metal type after the secondary processing, such troubles that the secondarily processed product is broken in this process, that extra salt of alkali metal or alkaline earth metal is left behind adhering as it is due to the defficiency of washing leading to decreased adsorption performance, and the like may be caused. Hence, for obtaining the alkali metal type or alkaline earth metal type adsorbents, a method of first converting the powder of proton type zeolites to alkali metal type or alkaline earth metal type by the neutralization method, ion-exchange method or combined method thereof, then performing the secondary processings such as molding and honeycombing is a rational implementing method.Here, molded products of zeolites produced without using binder are shown in publications of Japanese Unexamined Patent Publication No. Sho 62-70225, No. Sho 62-138320, etc. Zeolites, the amount of solid acid by Py-TPD thereof being brought to not more than 0.05 mmol/g by hydrothermal calcination treatment or neutralization or ion-exchange method using hydrophobic zeolites after the dealumination treatment by such molded products of zeolites containing no binder component, have high adsorption level, which are more suitable as the adsorbents.The adsorbents used in the method of the invention are particularly useful as adsorbents for cleaning waste gas containing ketonic organic solvents such as methyl ethyl ketone, methyl isobutyl ketone and cydohexanone. They can be suitably used in any device of fixed bed adsorption device, fluidized bed adsorption device, moving bed adsorption device, honey comb rotor thickening device, etc. Moreover, as the methods for adsorption and desorption procedure, there are pressure swing adsorption method, thermal swing adsorption method, combined method thereof, etc., but the inventive adsorbents can be applied to any mode.With the adsorbents of the invention, the adsorption procedures such as thickening of and solvent recovery from waste gas of ketonic organic solvents, which were difficult hitherto, have become possible without special contrivance for the adsorption device. Moreover, since the adsorbents do not exhibit the catalytic property at all, the dangers such as corrosion of adsorption device and firing of adsorbent bed, which were problematic hitherto, have been eliminated.In following, explanation will be made about the examples of the invention.Example 1Y type zeolite with a SiO2/Al2O3 molar ratio of 14 and a lattice constant of 24.33 angstroms was dealuminated with 1.5 N aqueous solution of hydrochloric add of 50 °C to obtain hydrophobic Y type zeolite with a SiO2/Al2O3 molar ratio of 500. To 100 parts by weight of this hydrophobic zeolite were added 25 parts by weight of day as a binder and a cylindrical molded product with a diameter of 3 mm was obtained. This molded product was calcined for 2 hours at 800 °C in air flow with a steam concentration of 20 vol. % to obtain an adsorbent Comparative example 1On the other hand, to 100 parts by weight of Y type zeolite with a SiO2/Al2O3 molar ratio of 14 not subjected to the dealumination treatment with aqueous solution of hydrochloric acid were added 25 parts by weight of clay as a binder and a cylindrical molded product with a diameter of 3 mm was obtained. This molded product was calcined for 2 hours at 800 °C in air flow with a steam concentration of 20 vol. % to obtain an adsorbent.Example 2Synthetic mordenite type zeolite was subjected to the dealumination treatment to obtain hydrophobic mordenite type zeolite with a SiO2/Al2O3 molar ratio of 200. To 100 parts by weight of this hydrophobic mordenite type zeolite were added 25 parts by weight of silica sol as a binder and a cylindrical molded product with a diameter of 3 mm was obtained. This molded product was calcined for 10 hours at 700 °C in air flow with a steam concentration of 20 vol. % to obtain an adsorbent.Comparative example 2Except that the calcination was carried out in dried air, treatment was made similarly to Example 2 to obtain an adsorbent.Example 3By the direct synthetic method, ZSM-5 type zeolite with a SiO2/Al2O3, molar ratio of 200 was obtained. After organic bases in zeolite were removed by calcining for 4 hours at 600 °C in atmosphere, 500 ml of 1M aqueous solution of NaCI were added to 100 g of this proton type hydrophobic ZSM-5, which was stirred to make a slurry. To this slurry was slowly added 0.1 N NaOH for neutralization. Further, this zeolite was washed sufficiently with warm water of 60 °C and dried overnight at 120 °C to obtain sodium type hydrophobic ZSM-5. To 100 parts by weight of sodium type hydrophobic ZSM-5 were added 25 parts by weight of silica sol as a binder, and a cylindrical molded product with a diameter of 1.5 mm was obtained, which was calcined for 2 hours at 600 °C in atmosphere to obtain an adsorbent.Comparative example 3To 100 parts by weight of proton type ZSM-5 type zeolite with a SiO2/Al2O3 molar ratio of 200 were added 25 parts by weight of silica sol as a binder and a cylindrical molded product with a diameter of 1.5 mm was obtained, which was calcined for 2 hours at 600 °C in atmosphere to obtain an adsorbent.Example 4Using synthetic mordenite type zeolite with a SiO2/Al2O3 molar ratio of 20, the dealumination treatment was conducted with mineral acid to obtain proton type hydrophobic mordenite. Subsequent treatment was made similarly to Example 3 to obtain an adsorbent.Comparative example 4On the other hand, to 100 parts by weight of proton type hydrophobic mordenite with a SiO2/Al2O3 molar ratio of 200 were added 25 parts by weight of silica sol as a binder, which was made into a cylindrical molded product with a diameter of 1.5 mm. This molded product was calcined for 2 hours at 600 °C in atmosphere to obtain an adsorbent.Of the adsorbents obtained in respective examples above, measurement of moisture adsorption capacity, determination of the amount of solid acid by Py-TPD method and adsorption and desorption test to methyl ethyl ketone were carried out by following methods. These results are shown in Table 1 and Table 2.(Moisture adsorption capacity)The adsorbent was placed in a crucible (w1 g) having been made constant weight and, after heated for 2 hours at 350 °C in an electric furnace to remove moisture, the adsorbent in crucible was cooled in a desiccator accommodated with drier and then weight (w2 g) was measured. This was then placed in a desiccator kept at a relative humidity of 30 % and, after allowed to stand for 24 hours at 20 °C, the weight (w3 g) was measured. The moisture adsorption capacity was determined using following equation. Moisture adsorption capacity(wt. %) = {(w3 - w2)/(w2- w1)} x 100<Determination of the amount of solid acid by Py-TPD method>The adsorbent was packed into a measurement tube and, after removed the moisture by treating 1 hour at 500 °C under vacuum, nitrogen was introduced, which was retained for 1 hour at 500 °C and then cooled to 300 °C. Further, pyridine gas vaporized with nitrogen was adsorbed onto the sample for 20 minutes at 300 °C. Next, the temperature of sample was increased from 300 °C to 950 °C at a temperature-raising velocity of 10 °C/min and the amount of pyridine coming to be eliminated was measured by means of gas chromatography (detector: flame ionization detector). The amount of solid acid in sample was determined by integrating the amount of pyridine eliminated on diagram within a range of 300 to 950 °C.<Adsorption and desorption test to methyl ethyl ketone>A glass column with an inner diameter of 6 cm and a length of 45 cm was used for the adsorption and desorption test. After packed the adsorbent into this column so as the height of bed to become 35 cm, adsorption and desorption test was conducted. The adsorption test was conducted at 25 °C. Air with a methyl ethyl ketone concentration of 3000 ppm (moisture concentration 10000 ppm) was flown through the bed of adsorbent at a flow rate of 0.2 m/sec and the time when the concentration of methyl ethyl ketone at exit portion reached 150 ppm was made saturation time (min). Further, the adsorption test was continued until the concentration of methyl ethyl ketone at exit portion reached 3000 ppm and the weight of column (Wa) after the completion of adsorption test was measured.For the desorption test, column was heated to 150 °C by ribbon heater while flowing dried air through the bed of adsorbent adsorbed methyl ethyl ketone at 0.075 m/sec. After continued until the exit concentration of methyl ethyl ketone reached lower than 10 ppm, column was cooled and the weight of column (Wd) after the completion of desorption test was measured. Moreover, the concentration of methyl ethyl ketone in eliminated gas was integrated on diagram to determine the amount of methyl ethyl ketone recovered (Wr).The recovery rate (%) of methyl ethyl ketone was calculated using following equation. Results are shown in Table 1. Recovery rate of methyl ethyl ketone (%) = Wr x 100/(Wa - Wb)The concentrations of methyl ethyl ketone at entrance and exit of the bed of adsorbent was measured by means of gas chromatography (detector FID). Saturation time (min)Recovery rate of methyl-ethyl ketone (%)Amount of solid acid (mmol/g)Example 126099.90.00Comparative example 126094.80.14Example 215199.20.03Comparative example 215584.70.08Moisture adsorption level (wt. %)Saturation time (min)Recovery rate of methyl-ethyl ketone (%)Amount of solid acid (mmol/g)Example 32.3310299.80.03Comparative example 32.769065.10.12Example 42.555799.80.01Comparative example 42.736084.70.08 | A method of cleaning waste gas containing ketonic organic solvents comprising contacting the waste gas containing ketonic organic solvents with an adsorbent comprising zeolite with an amount of solid acid of not more than 0.05 mmol/g as determined by pyridine temperature programmed desorption method and with a SiO2/Al2O3 molar ratio of not less than 50.The method according to claim 1, wherein the zeolite is one obtained by giving the hydrothermal calcination treatment.The method according to Claim 1, wherein the zeolite comprises hydrophobic zeolite of alkali metal type or alkaline earth metal type. | TOSOH CORP; TOSOH CORPORATION | HARADA MASASHI; INOUE TAKAHIKO; HARADA, MASASHI; INOUE, TAKAHIKO |
EP-0490045-B1 | 490,045 | EP | B1 | EN | 19,951,227 | 1,992 | 20,100,220 | new | H04N1 | null | G06T1, H04N1, H04N9 | H04N 9/04B, H04N 1/48C | Single-scan time delay and integration color imaging system | An electronic imaging system develops red, green and blue images of a document in a single pass of the document through the system. The system includes an image sensor which has three time delay and integration (TDI) sensor arrays. Each sensor array is configured to have two optically masked rows of charge coupled devices (CCD's) for every row of CCD's that is used for imaging. The sensor arrays are arranged so that the first row of imaging CCD's on any two successive arrays are separated by a distance of an integer, K, times three times the height of a picture element (pel) of the image of the document that is projected onto the image sensor, plus or minus one pel height. The spectral component of the image of the document that is projected onto the image sensor is changed in sequence from red, to green, to blue. As the spectral component projected onto the image sensor is changed, the image of the document is scanned down the image sensor by a distance of one pel height. By this scheme, each line of pels in the document is imaged in each of the sensor arrays in a respectively different spectral component. A document may be imaged in all three colors in a single pass through the system without having dedicated filters for each of the separate sensor arrays. | Field of the InventionThis invention relates generally to a system and a method which captures high-resolution color images and in particular, to a line-sequential color imaging system which employs three time delay and integration (TDI) sensors to obtain a color image of a document. BackgroundElectronic color imaging systems generally capture three distinct spectral components of an image, for example, red, green and blue. Each of these components is represented by an electrical signal. In many applications, the separate electrical signals are sampled and digitized. If the image is to be stored, the digital samples may be written into a digital memory. The image may be reproduced by applying the three signals to a device which combines the colors represented by the three signals. Sequential color imaging systems are well known. In these systems, a single image sensing device sequentially receives, for example, red, blue and green color information at a high rate relative to the rate at which the image is changing. If a document is moving during the imaging operation, The system must operate at relatively high frequencies since the document must be resolved into three distinct signals while it is held momentarily still. Other existing systems use a single linear or time delay and integration (TDI) imaging device to capture three separate scans of a document, each taken with a separate filter in place near the lens. The imaging device generally resolves lines of picture elements (pels) and scans the image incrementally, line by line. Either the document, the entire system except the document, the imaging device or a system of mirrors may be moved to provide the scan. The primary disadvantage of a system of this type is the time required for three scans at a given maximum output data rate. If the document must move while it is being scanned, it may be necessary to make three passes through the system to obtain all three images. These passes add to the time required to process the document and may present undesirable alignment problems. One method of avoiding multiple passes is to use three separately packaged imaging devices together with a system of spectrally selective beam splitters and filters. In this system, a different spectral band is applied to each device. These systems are disadvantageous because they require expensive optical components and need precise alignment. Multiple passes over the image may also be avoided by placing three imaging devices close together on a single chip or substrate arranged such that each device is exposed to light in a different spectral band. This may be done in several ways. According to a first method, the light from the illuminated image may be dispersed so that the different devices are simultaneously exposed to different spectral bands. This method requires a linear filament illuminator and expensive optical components. Moreover, this method makes inefficient use of its illuminator and is not suitable for scanners which move only the imaging device. A second method employs a uniform illuminator but places different filters over the different imaging devices. This method is disadvantageous since it requires special technology to apply and align the filters to the devices. A paper by Yao et al. entitled A Spatial Image Separator for Color Scanning SPIE Vol 809 - Scanning Imaging Technology pp 52-54, March 1987, describes a single-pass TDI color imager which uses a single TDI array. This system requires relatively complex and, thus, expensive optical components. U.S. Patent US-A-4,500,914 to Watanabe et al. relates to a color imaging array in which red, green and blue sensor elements are defined by a single charge coupled device (CCD) imaging array that is tessellated with respective red, green and blue filter elements. U.S. Patent US-A-4,264,921 to Pennington et al. relates to a single-pass color imager having three TDI arrays which each receive different spectral illumination. U.S. Patent US-A-4,628,350 to Aughton et al. concerns an imaging system in which a light beam is passed through a moving transparency, through a rotating filter element and onto a single linear imaging device. The rotating filter element sequentially passes light in three distinct spectral components. The light is converted into electrical signals by the single imaging device. Aughton teaches the use of a single linear imaging device with rapidly changing spectral image components. The advantages of TDI imaging arrays over linear imagers are well known: higher effective sensitivity to light and greater spatial uniformity and fidelity in the captured image. In a single-pass imager, however, TDI arrays cannot be substituted for linear arrays in a straightforward manner. This is because TDI imaging arrays operate in a pipelined mode, containing an electronic representation of several image pel lines at all times. Thus, if known TDI arrays were substituted for the linear arrays, the three color images would be mixed together, preventing color image reproduction from the electronic output. It is therefore an object of the present invention to combine the advantages of a single-pass color imager with those of TDI imagers. Summary of the InventionThe present invention is embodied in a system and method for generating multiple spectrum image of a document in a single scan as claimed in claims 1 and 10. Brief Description of the DrawingsFig. 1is a perspective drawing partly in block diagram form which illustrates the configuration of key elements of the imaging system. Fig. 2 is a plan drawing which illustrates the structure of two optical filters suitable for use in the imaging system shown in Fig. 1. Fig. 3is a block diagram which shows how the imaging system shown in Fig. 1 may be used. Fig. 4is a plan drawing of the sensor element used in the imaging system shown in Fig. 1. Fig. 4a is an expanded plan drawing of a portion of the sensor element shown in Fig. 4. Detailed Description of Exemplary Embodiments of the InventionOverviewAlthough the invention is described in the context of a color imaging system in which an image of a scanned document is developed from three component primary color images, it is contemplated that it may be used to develop other types of multiple spectrum images. For example, it may be desirable to capture both a visible light image and an infra-red image of an object other than a document in a single scan or to capture a polychrome image and one or more monochrome images. One skilled in the art of designing imaging systems could readily adapt this invention to perform these functions. The present invention is described in the context of a color imaging system suitable for use in an optical scanner or a color facsimile machine. In these systems, the document is moved through the machine in incremental steps. As the document is moved an image of at least a portion of the document moves across a sensor array. The exemplary imaging system also includes a rotating disk having three optical filters designed to produce final captured images corresponding to the red, green and blue spectral bands defined by the Commission Internationale de L'Eclairage (CIE). The rotation of the disk is synchronized to the motion of the document so that, as each new line of pels is imaged onto the sensor array, it is illuminated by a different spectral component of the light. The sensor array used in the described embodiments includes three TDI imaging devices. The basic operational principles of TDI imaging devices are described in U.S. Patent US-A-4,264,921 to Pennington et al. In the exemplary embodiments of the invention, each of the three TDI devices has two masked lines of charge transfer elements for every unmasked line of pel sensing charge transfer elements. The shifting of pel signals through the pel sensing elements and masked elements of the parallel lines of charge transfer devices is also synchronized to the motion of the document. This synchronization insures that as each new line of pels is imaged onto the device, the charge packets representing the previously captured line are shifted to the next charge transfer element. In the exemplary embodiments of the invention each TDI sensor includes three lines of pel sensing elements (e.g. lines 412, 414 and 416 of Fig. 4), separated from each other by two lines of masked charge transfer elements (e.g. lines 412′ and 412″ of Fig. 4). As the document is scanned, the charge accumulated in line 412 is shifted into lines 412′, 412″ and 414 in sequence. The scanning of the document and the shifting of pel samples through the TDI elements is synchronized so that, as each line of pel samples is shifted between successive lines of pel sensing elements (e.g. between lines 412 and 414), the respective sensing elements are illuminated by the same line of pels and the same spectral component. Thus, in the exemplary embodiment of the invention, the charge accumulated by the TDI device for each spectral component of each scanned line of pels is integrated over three exposure intervals. As the pel samples are shifted out of the final line of pel sensing elements (e.g. 416) they are applied to a serial charge transfer shift register (e.g. 418) which rapidly shifts the entire line of samples as an analog signal (e.g. OUT1). The three TDI sensors are arranged so that, as a line of pels from the document is applied to each of the sensors, it is illuminated by a different spectral component. Thus, for a given line of pels scanned from the document, its red spectral component is available at OUT1, later, its green component is available at OUT2 and later still, its blue component is available at OUT3. The different spectral signals are available at different times due to the time required to scan the line of pels over the sensors 302, 304 and 306. Each of the sensors 302, 304 and 306 provides signals representing three different spectral components of any three successive lines of pels. For example, the sensor 302 may provide the red, green and blue components for respective successive lines L1, L2 and L3 while sensor 304 provides the green, blue and red components and sensor 306 provides the blue, red and green components, respectively. Thus all three color components of a line of pels are provided as the three lines are scanned across all three of the sensors. Detailed DescriptionFig. 1 is a perspective drawing, partly in block diagram form, of an optical imaging system which includes an embodiment of the present invention. In Fig. 1, control and data gathering functions performed by a processor 122 are accomplished via bidirectional connections to the processor, illustrated in block diagram form. As shown in Fig. 1, a document 108 is moved through the imaging system on a belt 110. The motion of the belt is governed by a motor 124 which is responsive to control signals provided by the processor 122. In the exemplary embodiment of the invention, the motor 124 may be, for example, a stepper motor having a relatively large number of steps per revolution (e.g. 200). Upon receiving a signal from the processor 122, the exemplary motor 124 advances one step, causing an incremental movement of the belt and thus, the document on the belt. The rate at which step signals are provided by the processor 122 determines the speed of the motor 124. In a first exemplary embodiment of the invention, the document is illuminated by two lamps 112 which may be, for example, conventional quartz halogen lamps. Light from the illuminated image of the document 108 is passed through a filter element 114R of a rotating color wheel 114 and is projected by a lens system 116 onto an imaging array 118. The lens system 116 may be any of a number of conventional lens systems which do not produce significant distortion in the image as it is scanned across the imaging array 118. The exemplary color wheel 114 has three filters 114R, 114G and 114B, which approximate the spectral distribution shapes required for imaging the respective red, green and blue CIE color spectra. These filters are separated by opaque areas 114P. The filters are shown shaped as sectors of a disk by way of example only. The color wheel is turned by a motor 120 to expose the imager 118 to different spectral components at different times. In the exemplary embodiment of the invention, the motor 120 is a stepper motor which is controlled by a pulse train provided by the processor 122. In the example, filter wheel 114 is shown in front of the lens 116. As a matter of design choice, it may, alternatively, be placed between the lens 116 and the imager 118. In a second exemplary embodiment of the invention, the lamps 112, color wheel 114 and stepper motor 120 are replaced by three sets of lamps 112R, 112G and 112B which emit red, green and blue light, respectively. Each of these lamps is controlled by the processor 122 to sequentially illuminate the document 108, and thus the image of the document on the imaging array 118, with the different spectral components. As indicated by the arrows next to the belt 110 and imaging array 118, as the document moves along the belt in an upward direction in the Fig., the image of the document moves across the imaging array 118 in a downward direction. In the exemplary embodiment of the invention, the imaging array contains three sensor arrays which are composed of charge-coupled devices (CCD's) operated in time delay and integration (TDI) mode. The imaging array 118 is described below in greater detail with reference to Figs. 4 and 4a. The TDI sensor arrays on the imaging array 118 capture images of lines of pels from the document 108 as photocharge packets. The amount of charge in a packet represents the brightness of the associated pel. Each line of pels corresponds to a fine horizontal line of the document 108. In this embodiment of the invention, the processor 122 applies a four-phase parallel clock signal to the TDI arrays on the imaging array 118. In response to each cycle of the four-phase clock, the charge packets in one line are shifted downward in the direction of the image motion. In the exemplary embodiment of the invention, each line of the image contains 2048 pels and each pel corresponds to a square on the document having an area of approximately .00003 square inches. Correspondingly, each line of sensors in the imaging array contains 2048 elements. In this embodiment of the invention, the processor 122 synchronizes the motion of the belt 110 and of the color wheel 114 to the parallel clock signal applied to the imaging array. For each cycle of the parallel clock signal the document on the belt is moved so that the image of the document advances vertically by one pel position on the imager 118. Also, for each pulse of the parallel clock signal the color wheel rotates to position the next filter between the lens and the document. The motion of the belt and the shifting of captured charge in the TDI arrays are timed to occur when the lens is blocked by one of the opaque regions, 114P of the color wheel 114. As set forth below, each color component of each line on the document may be imaged several times as it is scanned across the imager. The amount of charge accumulated for each pel position of the line is proportional to the amount of time that the line is imaged. When a line of pels has been captured and integrated by the TDI sensor, it is shifted out as an analog signal in response to a serial clock signal supplied to the sensor array 118 by the processor 122. This analog signal is a time sequence of accumulated charge packets representing a line of pels in the document. Since the sensor array 118 includes three TDI sensors, it is continuously providing three analog signals. In the exemplary embodiment of the invention, the three sensor arrays are configured to provide, at any instant, signals representing three different color spectra. For example, during one cycle of the parallel clock signal the three sensor arrays may provide red, green and blue color signal components, respectively, while in the next parallel clock cycle they may provide blue, red and green, respectively. These signals are resolved into separate red, green and blue images by the processor circuitry described below with reference to Fig. 3. The sensor arrays provide respectively different color signals at any given time because the number of masked lines of charge transfer elements between the bottom row of imaging elements and the serial register are different for the three arrays. These masked lines delay each output line by one parallel cycle. Thus, varying the delay in each array changes the relationship between the output signals. If, for example, each array had the same delay, all three arrays would simultaneously provide output signals for the same color. Fig. 2a is a plan diagram of the color wheel 114 shown in Fig. 1. This color wheel includes three filters, one each having a spectral distribution which, when combined with the spectral content of the lamps and the spectral response of the imager, corresponds to the red, green and blue CIE color spectra. These exemplary filters, however, produce only rough approximations of the respective CIE spectral bands which are shown in Fig. 2c. As shown in this Fig., the blue spectral band z has a peak at 450 nanometers (nm), the green spectral band y has a peak at 540 nm and the red spectral band x has two peaks, one at 600 nm and one at 435 nm. The peak at 435 nm is at approximately the same wavelength as the peak of the blue spectral filter. The red filter 114R in the exemplary color wheel 114 ignores the effect of the blue peak on spectral transmission. Accordingly, while this filter may provide an adequate translation of color from a document to an electronic image, this translation is not as accurate as it could be. Greater accuracy in the transmission spectrum of the red filter may be achieved by adding a fourth filter to the color wheel, as shown in Fig. 2b. In this wheel, the red filter 114R is replaced by two smaller filters 114RP and 114BP. The filter 114RP has a transmission spectrum which approximates the peak of the x CIE tristimulus curve at 600 nm. The transmission spectrum of the filter 114BP is a reduced-amplitude version of the z tristimulus curve. This approximates the peak of the x curve at 435 nm. The inventors have found this to be a good approximation of the double-peak x transmission spectrum. In the exemplary embodiment of the invention, the red peak filter 114RP is smaller than the red filter 114R shown in Figs. 1 and 2a. This filter provides acceptable performance, however, since the TDI sensors exhibit greater sensitivity to light at the red end of the spectrum than to light at the blue end of the spectrum. In operation, the imaging array 118 would be exposed light from both of the filter elements 114RP and 114BP during a single cycle of the parallel clock signal PC. The array 118 would only be exposed to light from one of the filter elements 114G and 114B respectively during each of the next two successive clock cycles. Although the wheel 114 is shown as only having one filter element of each color, it is contemplated that an alternative wheel may have multiple filter elements of each color. This would be advantageous since it would allow the speed of the stepper motor 120 to be reduced, since all of the filter elements could be inserted between the document and the imaging array 118 is a portion of the rotational period of the motor. As shown in Fig. 1, the lamps 112, color wheel 114 and stepper motor 120 may be replaced by three sets of filtered light sources 112R, 112G and 112B which are individually activated by the processor 122 at times corresponding to the illumination of the image by the filters in the wheel 114 in the embodiment described above. In this alternative embodiment, the blue peak of the x CIE tristimulus curve may be approximated by briefly activating the blue light source during the time interval in which the red light source is activated. Fig. 3 is a block diagram which shows details of the imaging array 118 and of the components of the processor 122 which send control signals to, and receive data from the imaging array 118. As described above, the imaging array 118 includes three component TDI arrays 302, 304 and 306. These arrays are described below, in greater detail, with reference to Figs. 4 and 4a. A clock generator circuit 330 provides parallel clock signals, PC, and serial clock signals, SC, to each of the component TDI arrays of the imaging array 118. It is understood that PC and SC each symbolically represent multiple conductors conveying multiple clock signals to the parallel and serial registers of the imaging arrays. For example, PC may comprise four parallel phases and a parallel-to-serial interface phase, while SC may comprise four serial phases, a set phase and a reset phase. All serial phases and all parallel phases have respective common frequencies. In this embodiment of the invention, the signals PC and SC have frequencies of approximately 4 KHz and 8 MHz, respectively. The exemplary clock generator circuit 330 also provides clock signals to stepper motor controllers 334 and 336 which control the belt stepper motor 124 and color wheel stepper motor 122, respectively. In addition, the clock generator provides other clock signals, described below, which are used by components of the processor 122. By controlling the frequency and phase of these clock signals, the processor 122 synchronises the motion of the belt 110, the color wheel 114 and the shifting of packets through the TDI sensor arrays as described above. Each of the component TDI arrays 302, 304 and 306 provides an analog output signal to a respective analog-to-digital converter (ADC) 308, 310 and 312. Each analog output signal is generated by serially shifting 2048 charge packets, representing a line of pels, from the array synchronous with the signal SC. The ADC's 308, 310 and 312 each receive, from the clock generator 330, a clock signal having the same frequency as the signal SC but with a phase determined by the analog output signal. In response to this signal, the ADC's 308, 310 and 312 generate digital values representing the respective analog charge packets provided by the imaging arrays 302, 304 and 306, respectively. Each of the ADC's 302, 304 and 306 provides the digital values that it produces to three multiplexers 314, 316 and 318. Each digital value is in the form of eight parallel bits. In this example this signal is shown as a single path for clarity. The multiplexers 314, 316 and 318 are all coupled to receive a two-bit control signal from a modulo-three counter 320. The clock input signal to the counter 320 is provided by the clock generator 330 and has substantially the same frequency as the parallel clock signal PC. As shown in Fig. 3, the multiplexer 314 is configured to pass the signal provided by the ADC's 308, 310 and 312 when the values provided by the counter 320 are 0, 1 and 2, respectively. For these values, the multiplexer 316 is configured to pass the values provided by the respective ADC's 310, 312 and 308, while multiplexer 318 is configured to pass the values provided by the ADC's 312, 308 and 310. In this configuration, the samples provided by each multiplexer represent a separate color component of the image. Which color component is passed by which multiplexer depends on the synchronization of the color wheel 114 to the clock signal PC. In the exemplary embodiment of the invention, the color wheel rotates to expose the sensor array to red, green and blue light in succession. Thus, with the proper phasing of the two-bit control signal, the exemplary multiplexers 314, 316 and 318 provide red, green and blue sample values, respectively. The samples provided by the multiplexers 314, 316 and 318 are applied to respective digital memory arrays 322, 324 and 326. Each of these memories has sufficient capacity to hold samples representing an entire document. In the exemplary embodiment of the invention, where the document 108 may be 11 by 14 inches and where each pel represents a square on the document having an area of .00003 square inches and 256 greyscale values, the exemplary memory arrays each contain more than 5,000,000 bytes (5 MB) of data storage. The memory arrays 322, 324 and 326 include conventional dual-port random access memory (RAM) elements. Data may be stored into these RAMs in response to a first set of address signals, provided by address logic 332, while stored data is independently read from the arrays in response to a second set of address signals, provided by application circuitry 328. This application circuitry may be, for example a conventional color facsimile transmission system. Due to the configuration of the imaging array 118, if red samples representing one line of pels (e.g. L1) are provided by the TDI sensor array 302, red samples for the next two lines on the document (e.g. L2 and L3) are provided by the sensor arrays 304 and 306, respectively. Not only are these lines of samples provided by different sensor elements but, in this embodiment of the invention, they are delayed, respectively, by 15 and 30 cycles of the parallel clock signal PC with respect to the line of samples provided by the sensor element 302. In addition to the above considerations for generating address values for successive lines of samples of a single color, other considerations exist for generating address values for the different color components of a single line of samples. Using the line L1 described above, if the TDI sensor array 302 provides the red samples for line L1, the sensor array 304 provides the green samples and sensor 308 provides the blue samples with respective delays of 14 and 28 cycles of the signal PC. To handle this addressing scheme, the exemplary address logic 332 is coupled to receive a clock signal, MC, having substantially the same frequency as the serial clock signal SC. In addition, the address logic 332 receives the counter value provided by the counter 320 to the multiplexers 314, 316 and 318. The exemplary logic circuitry 332 contains three address counters (not shown), one for each of the memories 322, 324 and 326 and stores three address values (not shown) for each memory. The address value that is loaded into a particular counter is determined from the signal provided by the modulo 3 counter 320. All three of the counters in the address logic 332 are incremented synchronously with the clock signal MC. The circuitry shown in Fig. 4 assumes that the various sensor arrays, 302, 304 and 306 simultaneously provide signals representing different spectral components. If, as set forth above, the sensor arrays are identical and, so, provide signals representing the same spectral components, the memory 322 would be segmented differently requiring changes in the address logic 332. One skilled in the art of designing image processing circuitry can readily design suitable circuitry to handle the signals provided by the alternative sensor arrays. Fig. 4 is an expanded plan view of the sensor array 118 shown in Figs. 1 and 3. Fig. 4a is a further expansion of a portion of the sensor array 302. These two Figs. are used to describe the configuration and operation of the imaging array 118. As described above, the imaging array 118 includes three component TDI sensor arrays, 302, 304 and 306. Sensor array 302 has three lines of 2048 pel imaging cells (412, 414 and 416) which accumulate charge when exposed to light. The imaging cells in lines 412 and 414 are separated by two lines of masked cells, 412′ and 412″. These masked cells are not light sensitive and merely act as two stages each of 2048 parallel CCD shift registers, which pass the charge packets from the line 412 to the line 414. There are also two lines of masked cells between the lines of pel imaging cells 414 and 416 and between the pel imaging cells in the line 416 and a 2048 stage parallel input serial output CCD shift register 418. Fig. 4a is a plan diagram of a portion of the TDI array 302. The array includes three rows of imaging cells, 412, 414 and 416. Each of the rows of imaging cells is separated from the next row by two rows of masked cells (e.g. 412′ and 412″). The parallel clock signal PC, includes, in this embodiment, four phase signals which are applied to all of the masked and unmasked rows of cells. The four-phase clock signal acts to transfer charge packets, in parallel, from one row of the TDI array to the next. The exemplary signal PC also includes a parallel-to-serial transfer phase. The discussion that follows describes the operation of the TDI array in terms of time intervals defined by successive cycles of the signal PC. During a first cycle of this signal, the charge packets P1, P2 and P3 are accumulated while row 412 is exposed to, for example, a line, L1 of pels from the document illuminated by red light (at the same time other charge packets are being accumulated in rows 414 and 416 by exposure to other lines of the document, also in red light). These charge packets are transferred to row 412′ to become the packets P1′, P2′ and P3′ at the start of the next cycle. During this time interval, the line of pels L1 is focused on row 412′ and the entire imaging array is exposed to green light. The amount of charge in the packets held in row 412′ is substantially unchanged during this cycle because the effect of light on the masked row of cells of row 412′ is negligible. During the next cycle, the packets P1′, P2′ and P3′ are transferred from the masked row 412′ to the masked row 412″ to become the packets P1″, P2″ and P3″. During this interval the pels of line L1 are focused on the row 412″ and the imaging array 118 is exposed to blue light. As with row 412′, the amount of charge in the packets P1″, P2″ and P3″ remains substantially constant; there is no contribution from the blue light. In the next cycle, the packets P1″, P2″ and P3″ are transferred into the imaging cells of row 414, becoming P1‴, P2‴ and P3‴. The pels of line L1 are then focused on the row 414 and the array 118 is again illuminated by red light. During this interval, the light shining on the imaging cells increases the charge in packets P1‴, P2‴ and P3‴. During the next two cycles of the signal PC, the charge packets representing the pels of line L1 are transferred through the cells 414′ and 414″. In the next subsequent cycle, charge is again accumulated in the packets while they reside in the imaging cells of row 416 and are exposed to line L1 in red light. These charge packets are then transferred through the rows 416′ and 416″ in the next two cycles. Upon leaving the row 416″, at the start of the next cycle, the accumulated charge packets are transferred, in parallel, into a parallel input, serial output shift register 418 by the parallel-to-serial phase of the clock signal PC. During that cycle, these charge packets are shifted out of the shift register 418 in response to the 8 MHz clock signals, SC. The set and reset phases of the signal SC aid in the generation of the analog output signal from the serial register. It is noted that, at any time, charge packets reside in all elements of each array so that the operations described above are occurring simultaneously throughout the imaging array. The structure of the component TDI arrays 304 and 306 is the same as the array 302 except for the number of rows of masked cells between the last imaging line and the output shift register. In the array 304, only one row of masked cells is present between the last line of pel imaging cells, 426 and output shift register 428. In the TDI array 306, the output shift register 438 is coupled directly to the last line of imaging cells, 436 with no intervening rows of masked cells. The number of lines of cells is different for the different TDI arrays to ensure that no two arrays will simultaneously provide samples of the same spectral component. As described above, all of the TDI arrays are simultaneously exposed to each of the three spectral components and all of the arrays are responsive to the clock signal PC to transfer the accumulated charge packets in each line to the next successive line. Thus, if all of the TDI arrays had the same number of lines then they would all simultaneously provide samples of the same spectral component at the output ports of their respective serial shift register stages. In the configuration shown in Fig. 4, while the TDI array 302 is providing red spectral samples at its output terminal, the arrays 304 and 306 are providing green samples and blue samples, respectively. The individual TDI arrays 302, 304 and 306 are arranged on the sensor array 118 so that the distance d between the first line of imaging cells on any two successive arrays is a multiple of the spacing represented by three lines of cells (imaging and non-imaging) plus the spacing represented by one additional line. As a practical design consideration, it is desirable that the spacing be large enough to permit electrical connections to the individual arrays 302, 304 and 306. In the exemplary embodiment, the distance d is equivalent to 16 line widths (5*3+1). In other embodiments of the invention where each TDI sensor array may include, for example, 33 lines of cells (11 imaging lines and 22 masked lines), a distance d of 52 line widths may be more appropriate. As an alternative, the distance d may be equivalent to a multiple of three line spacings, minus one line spacing. In Fig. 4, the spacing between the arrays is not shown to scale. This arrangement of the respective TDI sensor arrays ensures that each line of pels is imaged in each of the three color spectra, red, green and blue. As set forth above, the motion of the belt is synchronized to the motion of the color wheel and the parallel clock signal PC so that for each cycle of the signal PC, the image of the document is moved vertically down the imager by one pel position and the color wheel is rotated to expose the imaging array to a different spectral component. Using this scheme, each unmasked row of imaging elements is exposed to the same lines of pels for a given spectral component. For example, when line 412 is exposed to a line of pels L1 in red light, lines 414 and 416 will also be exposed to the same line of pels in red light respectively 3 and 6 cycles of the signal PC after line 412 is exposed. As the image of the document is scanned down the imaging array 118, if a given line L1 is exposed in red light on the imaging lines of the TDI array 302, it is exposed in green light on the imaging lines of the TDI array 304 and in blue light on the imaging lines of the TDI array 306. Thus, every line of pels in the document is imaged in all three spectral components. In the exemplary embodiment of the invention, there are delays of 15 and 30 cycles of the signal PC between the time that the line of pels in one spectral component is provided by the TDI array 302 and the times that the other two spectral components of the line are provided by the respective TDI arrays 304 and 306. These delays would increase if each of the TDI arrays used more rows of cells or if the spacing between successive TDI arrays were increased. While the described embodiments of the invention use TDI sensor arrays, it is noted that linear image sensors (not shown) may be substituted for the TDI arrays. In this alternative embodiment, three linear image sensors would be placed in the same relative positions on the sensor array 118 as described above. Each successive pair of linear sensors would have the spacing between their lines of imaging cells as described above. This configuration of linear sensors would allow the use of a lower data rate from each sensor than in the imaging apparatus set forth in the above referenced Aughton patent. While this invention has been described in terms of an exemplary embodiment, it is understood that it may be practiced as outlined above within the scope of the attached claims. | A system for capturing multiple spectral components of an image of an object as a matrix of picture elements (pels) comprising: image sensing means (118), including M sensor elements (302, 304, 306), where M is an integer, for simultaneously generating M electrical signals representing M lines of pels, respectively, from the image of the object; imaging means (116) for projecting the image of the object onto said image sensing means; scanning means for scanning the image of the object across said image sensing means; characterized by: spectral control means (114) for changing spectral components of the image of the object that are projected onto said image sensing means from among N spectral components, where N is an integer not less than M; and control means (122) for synchronizing the spectral control means and the scanning means such that, as a line of pels from the image of the object is scanned across said image sensing means once, images of at least M of said N spectral components of the line are projected in succession onto the M sensing elements, respectively. The system of claim 1 wherein the M sensor elements of said image sensing means include M respective time delay and integration (TDI) sensor arrays, each of said TDI sensor arrays including multiple rows of image sensing elements, wherein: each row of image sensing elements is configured to sense a line of pels from the projected image of the object; and each row of image sensing elements is separated from the next row of image sensing elements by M-1 rows of optically masked charge transfer elements. The system of claim 2 wherein: each pel of the projected image of the object has a predetermined height, H,; and the respective first rows of image sensing elements on successive ones of said M sensor elements are separated by a distance, D, which is defined by the equation D = [(K * M) + 1] * H, where K is an integer. The system of claim 2 wherein: each pel of the projected image of the object has a predetermined height, H,; and the respective first rows of image sensing elements on successive ones of said M sensor elements are separated by a distance, D, which is defined by the equation D = [(K * M) - 1] * H, where K is an integer. The system of one of claims 1 to 4 wherein: the spectral control means (114) is responsive to said control means (122) to change the spectral component of the image of the object that is projected onto the image sensing means (118) at respective regular time intervals each having a duration of T; and the scanning means is responsive to the control means to scan the image of the document across the image sensing means by a distance substantially equal to H during the time T. The system of one of claims 1 to 5 wherein the spectral control means includes: means (112) for simultaneously illuminating the object with polychromatic radiation including said multiple spectral components; and filter means (114) including N filter elements, disposed between the object and the image sensing means, for successively filtering radiation reflected from the object which is imaged onto the image sensing means through at least M of said N filter elements. The system of claim 6 wherein said filter means includes a color wheel having three filter elements which approximate respective red, green and blue CIE tristimulus spectra. The system of claim 7 wherein the filter element which approximates the red CIE tristimulus spectrum includes a first filter having a transmission spectrum with exhibits a peak transmission for light waves having a wavelength of approximately 600 pm and a second filter having a transmission spectrum which approximates the blue CIE tristimulus spectrum. The system of one of claims 1 to 8 wherein the spectral control means (114) includes means (112R, 112B, 112G) for sequentially illuminating the object with each of said respective multiple spectral components. A method of capturing multiple spectral components of an image of an object as a matrix electrical signals representing picture elements (pels) for use in an imaging system including an image sensor array including M sensor elements (302, 304, 306), where M is an integer, for simultaneously generating M electrical signals representing M lines of pels comprising the steps of: a) projecting the image of the object onto the image sensor array; b) scanning the projected image of the object across the sensor array; characterized by the further steps of: c) changing the spectral component of the image projected onto the image sensor array from among N spectral components, where N is an integer not less than M; d) synchronizing steps b) and c) so that, as a line of pels from the image of the object is scanned across the image sensor array once, images of at least M of the N spectral components of the line of pels are projected in succession onto the M sensor elements, respectively. | IBM; INTERNATIONAL BUSINESS MACHINES CORPORATION | SCHLIG EUGENE STEWART; YAO YING LUH; SCHLIG, EUGENE STEWART; YAO, YING LUH |
EP-0490048-B1 | 490,048 | EP | B1 | EN | 19,970,813 | 1,992 | 20,100,220 | new | H01M10 | null | H01M10, H01M6 | H01M 10/40E1, H01M 10/40 | Non-aqueous electrolyte cell | A non-aqueous electrolyte cell comprising a positive electrode, a negative electrode, and an electrolyte consisting of a solute and an organic solvent, characterized in that the solvent is a solvent mixture of a cyclic carbonate and a non-cyclic carbonate. | BACKGROUND OF THE INVENTION1) Field of the InventionThe present invention relates to a non-aqueous electrolyte cell comprising a positive electrode, a negative electrode and a non-aqueous electrolyte consisting of a solute and an organic solvent. 2) Description of the Prior ArtA non-aqueous electrolyte cell in which a negative electrode has lithium or a lithium alloy as an active material provides advantages of high energy density and low self-discharge rate. A low boiling point solvent such as dimethoxyethane or dioxolane has been conventionally used as a solvent of an electrolyte. However, this gives rise to the problem that the solvent reacts with lithium to form a film, which is inactive and has a low conductivity, on the surface of the negative electrode. This causes an increase in the internal resistance of the cell, resulting in a decline in the cell performance during the life time of the cell (especially of the high rate discharge characteristics). In order to solve the above problem, it has been proposed to employ a solvent mixture of a cyclic carbonate and a low boiling point solvent to form a film of Li2CO3 having a high conductivity on the surface of the negative electrode, thereby improving the life time. However, lithium reacts, though very slightly, with a low boiling point solvent, and an inactive film (Li2O) is formed on the surface of the negative electrode. This decreases the high rate discharge characteristics after a long storage period. As another method for solving the problem, a non-aqueous electrolyte cell using a solvent mixture of a cyclic carbonate and an non-cyclic carbonate has been developed. For example, a cell disclosed in JP-A 61064082 includes LiCF3SO3 as a solute and a solvent mixture of a cyclic carbonate (PC) and a non-cyclic carbonate (DEC). The non-aqueous electrolyte secondary cell of FR-A-2641130 also uses a solvent mixture of a cyclic carbonate and a non-cyclic carbonate. As described above, it is possible to improve the high rate discharge characteristics by using a solvent mixture of a cyclic carbonate and a non-cyclic carbonate to form a film of Li2CO3, which does not increase the internal resistance of the cell, on the surface of the negative electrode. With such arrangement, the life time is improved, the formation of a Li2O film can be prevented, and the high rate discharge characteristics after a long storage period is improved. However, a further techique is sought for improving the amount of discharge after a long storage period. EP-A-0 486 950 discloses another non-aqueous electrolyte cell. Especially, this document shows a non-aqueous electrolyte secondary battery is essentially comprising of a negative electrode which comprises a carbonaceous material capable of doping and de-doping lithium, a positive electrode made of an active material which comprises a Li-containing metal complex oxide of the general formula LixMO2, wherein M represents at least one member selected from the group consisting of Co, Ni and Mn and 0.5 ≤ x ≤ 1, and a non-aqueous electrolyte which contains an electrolyte and an organic solvent therefor. The organic solvent is a mixed solvent of propylene carbonate and at least one member selected from the group consisting of diethyl carbonate and dipropyl carbonate. Since this document with the priority dated 17.11.1990 has been published on 27.5.1992 it constitutes state of the art only under article 54(3) (4)EPC. SUMMARY OF THE INVENTIONAn object of the present invention, therefore, is to provide a non-aqueous electrolyte cell capable of drastically improving a high rate discharge characteristic after storage as well as before storage. Another object of the present invention is to provide a non-aqueous electrolyte cell capable of improving a charge and discharge cycle characteristic before and after storage when used as a secondary cell. Still another object of the present invention, therefore, is to provide a non-aqueous electrolyte cell with the improved amount of discharge having high stability after a long storage period. The above objects are achieved by a non-aqueous electrolyte cell according to claim 1, a dischargeable non-aqueous electrolyte primary cell according to claim 4 and a rechargeable non-aqueous electrolyte secondary cell according to claim 6. The dependent claims are related to different developments of the present invention. The above objects are fulfilled for the following reasons: A storage characteristic in a non-aqueous electrolyte cell is deteriorated since a film having a low conductivity is generated by reaction between lithium and a solvent during long-term storage. When the solvent comprises a cyclic carbonate such as propylene carbonate or ethylene carbonate, a film of Li2CO3, which does not increase the internal resistance of the cell, is formed on the negative electrode, whereby the storage characteristic can be improved. However, if the solvent consists of a cyclic carbonate only, the high rate discharge characteristic is deteriorated due to high viscosity of the electrolyte. Therefore, a solvent mixture of a cyclic carbonate and a low boiling point solvent having a low viscosity such as dimethoxyethane or dioxolane is generally used. However, such a solvent mixture also has a problem that reaction between lithium and the low boiling point solvent is inevitable after long term storage although the high rate discharge characteristic is improved. The reaction forms an inactive film of Li2O, whereby the high rate discharge characteristic is deteriorated after long term storage. In order to solve the above problems, the present invention employs a solvent mixture of a cyclic carbonate and a non-cyclic carbonate having a low viscosity. In this case, the viscosity of the electrolyte becomes lower than the case of the cyclic carbonate solvent, whereby the high rate discharge characteristic is improved. Moreover, since each carbonate forms a film of Li2CO3, the post-storage high rate discharge characteristic is further improved. When the present invention is applied to a secondary cell, thanks to the formation of the film having a high conductivity, not only the storage characteristic but also the charge and discharge cycle characteristic are improved. BRIEF DESCRIPTION OF THE DRAWINGSThese and other objects, advantages and features of the invention will become apparent from the following description thereof taken in conjunction with the accompanying drawings which illustrate specific embodiments of the invention. In the drawings:- Fig. 1 is a sectional view of a flat type non-aqueous electrolyte cell according to an embodiment of the present invention, Fig. 2 is a graph showing initial high rate discharge characteristic of Cell A according to the present invention and Comparative Cells X1 and X2, Fig. 3 is a graph showing post-storage high rate discharge characteristics of Cells A, X1 and X2, Fig. 4 is a graph showing relationship between the mixing ratio of ethylene carbonate and dimethyl carbonate and discharge capacity, Fig. 5 is a graph showing initial high rate discharge characteristics of Cell B and Comparative Cells Y1 and Y2, Fig. 6 is a graph showing post-storage high rate discharge characteristics of Cells B, Y1 and Y2, Fig. 7 is a graph showing initial high rate discharge characteristics of Cell C according to the present invention and Comparative Cells Z1 and Z2, Fig. 8 is a graph showing post-storage high rate discharge characteristics of Cells C, Z1 and Z2, and Fig. 9 is a graph showing relationship between the mixing ratio of propylene carbonate and dimethyl carbonate and discharge capacity. DESCRIPTION OF THE PREFERRED EMBODIMENTSEmbodiment I [Example 1] Fig. 1 is a sectional view of a flat type non-aqueous electrolyte primary cell as an embodiment of the present invention. The cell comprises a negative electrode 1 formed of lithium metal and pressed upon an inner surface of a negative collector 2. The negative collector 2 is secured to an inner bottom surface of a negative can 3 formed of ferritic stainless steel (SUS430). The negative can 3 is peripherally secured in an insulating packing 4 formed of polypropylene, while a positive can 5 is secured peripherally of the insulating packing 4. A positive collector 6 is secured to an inner bottom surface of the positive can 5. A positive electrode 7 is secured to an inner surface of the positive collector 6. A separator 8 impregnated with an electrolyte is disposed between the positive electrode 7 and the negative electrode 1. The positive electrode 7 was produced as follows. First, manganese dioxide heat-treated in a temperature range of 350-430°C acting as an active material, carbon powder acting as a conductive agent and fluororesin powder acting as a binder were mixed in a weight ratio of 85:10:5. Then, the mixture was molded under pressure and heat-treated at 250-350°C. The negative electrode 1 was produced by punching a piece having a predetermined size out of a rolled plate of lithium. The electrolyte was prepared by dissolving lithium phosphate hexafluoride in an equivalent volume solvent mixture of ethylene carbonate and dimethyl carbonate in 1mol/l. The cell has a diameter of 20.0mm, a height of 2.5mm and a capacity of 130mAh. The cell manufactured as above is referred to as Cell A, hereinafter. [Comparative Example 1]A cell was manufactured in the same way as Example 1 except that a solvent of ethylene carbonate was employed instead of the solvent mixture of ethylene carbonate and dimethyl carbonate. The cell manufactured as above is referred to as Cell X1, hereinafter. [Comparative Example 2]A cell was manufactured in the same way as Example 1 except that an equivalent volume solvent mixture of ethylene carbonate and dimethoxyethane was employed instead of the solvent mixture of ethylene carbonate and dimethyl carbonate. The cell manufactured as above is referred to as Cell X2, hereinafter. [Experiment 1]With respect to Cells A, X1 and X2, initial high rate discharge characteristics immediately after cell assembly and post-storage high rate discharge characteristics after the cells were stored for 3 months at 60°C were checked. Figs. 2 and 3 respectively show the results. The experiment was conducted under the condition that the cells were discharged with a constant resistance of 300Ω at 25°C. As apparent from Figs. 2 and 3, Cell A according to the present invention is superior in both initial and post-storage high rate discharge characteristics. In contrast, Cell X1 is excellent in the post-storage high rate discharge characteristic but is poor in the initial high rate discharge, whereas Cell X2 is excellent in the initial high rate discharge characteristic but is poor in the post-storage high rate discharge characteristic. This is considered due to the following reasons. 1) Comparative Cell X1Cell X1 employs the solvent consisting of one cyclic carbonate (ethylene carbonate). Therefore, a film of Li2CO3 is formed by reaction between lithium of the negative electrode and the solvent as in Cell A of the present invention. This restricts deterioration of the post-storage high rate discharge characteristic. However, due to high viscosity of the electrolyte, the initial high rate discharge characteristic is lowered. 2) Comparative Cell X2In Cell X2, the solvent contains a low boiling point solvent(dimethoxyethane). This prevents the viscosity of the electrolyte from being heightened, thereby improving the initial high rate discharge characteristic. However, after long-term storage at a high temperature, the low boiling point solvent reacts on lithium, whereby an inactive film of Li2O is formed on surfaces of the negative electrode. As a result, the post-storage high rate discharge characteristic is lowered. 3) Cell A of the present inventionSince the solvent contains a non-cyclic carbonate (dimethyl carbonate), the viscosity of the electrolyte is prevented from being heightened, resulting in improvement in the initial high rate discharge characteristic. Further, since a film of Li2CO3, which does not increase the internal resistance of the cell, is formed, deterioration of the high rate discharge characteristic after long-term storage is restricted. [Experiment 2]An optimum ratio range of ethylene carbonate and dimethyl carbonate was found by checking the relationship between the mixing ratio and discharge capacity. The experiment was conducted under the condition that the cell manufactured in the same way as Cell A was discharged with a constant resistance of 300Ω at 25°C after storage for 3 months at 60°C. As apparent from Fig. 4, it is preferable that ethylene carbonate is contained in a range of 30-70vol%. Comparative Embodiment II[Example 1]A cell was manufactured in the same way as Example 1 of Embodiment I except that lithium trifluoromethane sulfonate was employed as the solute and that an equivalent volume solvent mixture of propylene carbonate and dimethyl carbonate was employed as the solvent. The cell manufactured as above is referred to as Cell B, hereinafter. [Comparative Cell 1]A cell was manufactured in the same way as the above Example 1 except that a solvent of propylene carbonate was employed. The cell manufactured as above is referred to as Cell Y1, hereinafter. [Comparative Cell 2]A cell was manufactured in the same way as the above Example 1 except that an equivalent volume solvent mixture of propylene carbonate and dioxolane was employed. The cell manufactured as above is referred to as Cell Y2, hereinafter. [Experiment]With respect to Cells B, Y1 and Y2, initial high rate discharge characteristics and post-storage high rate discharge characteristics were checked. Figs. 5 and 6 show the results. The experiment condition was the same as Experiment 1 of Embodiment I. As apparent from Figs. 5 and 6, Cell B is superior in both initial and post-storage high rate characteristics. In contrast, Comparative Cell Y2 is excellent in the initial high rate discharge characteristic but is poor in the post-storage high rate discharge characteristic. Comparative Cell Y1 is excellent in the post-storage high rate discharge characteristic but is poor in the initial high rate discharge characteristic. Embodiment III[Example 1]In this embodiment, the present invention is applied to a secondary cell. The secondary cell in this embodiment has substantially the same construction as the cell of Fig. 1 except the kinds of an active material for the positive electrode and an electrolyte. More specifically, rechargeable cobalt oxide is used as the active material for the positive electrode and the electrolyte is prepared by dissolving lithium phosphate hexafluoride in an equivalent volume solvent mixture of propylene carbonate and dimethyl carbonate in 1mol/l. The cell manufactured as above is referred to as Cell C, hereinafter. [Comparative Example 1]A cell was manufactured in the same way as the above Example 1 except that a solvent of propylene carbonate was employed. The cell manufactured as above is referred to as Cell Z1, hereinafter. [Comparative Example 2]A cell was manufactured in the same way as the above Example 1 except that an equivalent volume solvent mixture of propylene carbonate and dimethoxyethane was employed. The cell manufactured as above is referred to as Cell Z2, hereinafter. [Experiment 1]With respect to Cells C, Z1 and Z2, initial cycle characteristics immediately after cell assembly and post-storage cycle characteristics after storage for 3 months at 60°C were checked. Figs. 7 and 8 respectively show the results. The experiment was conducted under the condition that the cells were repeatedly charged with a charge current of 2mA for 3 hours and discharged with a discharge current of 2mA for 3 hours until the cell voltages drop to 2.5V. As apparent from Figs. 7 and 8, Cell C according to the present invention is superior to Comparative Cells Z1 and Z2 in both initial and post-storage cycle characteristics. [Experiment 2]An optimum mixing ratio range of propylene carbonate and dimethyl carbonate was found by checking the relationship between the mixing ratio and the post-storage cycle number. Fig. 9 shows the result. As apparent from Fig. 9, it is preferable that propylene carbonate is contained in a range of 30-70vol%. Other PointsIn the above three embodiments, ethylene carbonate or propylene carbonate is employed as the cyclic carbonate. Other cyclic carbonates such as butylene carbonate, vinylene carbonate may also be employed. In the above embodiments, dimethyl carbonate is employed as the non-cyclic carbonate. Methyl ethyl carbonate may also be employed. The negative electrode is not limited to lithium metal but may be formed of a lithium alloy such as a lithium-aluminum alloy. Although the present invention has been fully described by way of embodiments 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, the scope of the present invention is limited only be the appended claims. | A non-aqueous electrolyte cell comprising: a positive electrode composed of manganese oxide or cobalt oxide, a negative eletrode, and an electrolyte consisting of LiPF6 as a solute and a solvent mixture of a cyclic carbonate and a non-cyclic carbonate, the amount of the cyclic carbonate in the solvent being from 30 vol% to 70 vol%, wherein the non-cyclic carbonate is selected from a group consisting of dimethyl carbonate and methyl ethyl carbonate. A non-aqueous electrolyte cell as claimed in claim 1, wherein the cyclic carbonate is selected from a group consisting of ethylene carbonate, propylene carbonate, butylene carbonate and vinylene carbonate. A non-aqueous electrolyte cell as claimed in claim 1, wherein the negative electrode is formed of either one of lithium and a lithium alloy. A dischargeable non-aqueous electrolyte primary cell comprising: a positive electrode composed of manganese oxide; a negative electrode including either one of lithium and a lithium alloy; and a non-aqueous electrolyte consisting of LiPF6 as a solute and a solvent mixture of a cyclic carbonate and a non-cyclic carbonate; the amount of the cyclic carbonate in the solvent is from 30 vol% to 70 vol%, wherein the non-cyclic carbonate is selected from a group consisting of dimethyl carbonate and methyl ethyl carbonate. A non-aqueous electrolyte primary cell as claimed in claim 4, wherein the cyclic carbonate is selected from a group consisting of ethylene carbonate, propylene carbonate, butylene carbonate and vinylene carbonate. A rechargeable non-aqueous electrolyte secondary cell comprising: a positive electrode composed of cobalt oxide; a negative electrode including either one of lithium and a lithium alloy; and a non-aqueous electrolyte consisting of LiPF6 as a solute and a solvent mixture of a cyclic carbonate and a non-cyclic carbonate; the amount of the cyclic carbonate in the solvent is from 30 vol% to 70 vol%, wherein the non-cyclic carbonate is selected from a group consisting of dimethyl carbonate and methyl ethyl carbonate. A rechargeable non-aqueous electrolyte secondary cell as claimed in claim 6, wherein the cyclic carbonate is selected from a group consisting of ethylene carbonate, propylene carbonate, butylene carbonate and vinylene carbonate. | SANYO ELECTRIC CO; SANYO ELECTRIC CO., LIMITED. | FURUKAWA NOBUHIRO; TAKAHASHI MASATOSHI; YOSHIMURA SEIJI; FURUKAWA, NOBUHIRO; TAKAHASHI, MASATOSHI; YOSHIMURA, SEIJI |
EP-0490061-B1 | 490,061 | EP | B1 | EN | 19,960,612 | 1,992 | 20,100,220 | new | C25D1 | C25D1, B41J2 | C25D1, B41J2 | C25D 1/04, B41J 2/16G, C25D 1/08, B41J 2/16M2, B41J 2/16M3D, B41J 2/16M8C, B41J 2/16M5, B41J 2/16M3W, B41J 2/16M4, B41J 2/16M8P | Process for continuously electroforming parts such as ink jet orifice plates for inkjet printers | A method for continuously manufacturing parts requiring precision micro-fabrication. According to the method, a surface of a mandrel (2) having a reusable pattern (11) thereon is moved through an electroforming bath (4). While the mandrel surface moves through the bath, a metal layer is deposited on the mandrel surface to define a pattern. After the metal layer has been deposited to the selected thickness, the metal layer is separated from the mandrel surface . | BACKGROUND OF THE INVENTIONField of the Invention:The present invention generally relates to a continuous process for forming parts by precision micro-fabrication and, more particularly, to a process for fabricating inkjet orifice plates for printheads of inkjet printers. State of the Art:It is known to provide printheads for inkjet printers wherein the printheads each include a substrate, an intermediate barrier layer, and a nozzle plate including an array of nozzle orifices, each of which is paired with a vaporization chamber in the substrate. Also, a complete inkjet printhead includes means that connect the vaporization cavities to a single ink supply reservoir. In practice, the print quality of an inkjet printers depends upon the physical characteristics of the nozzles in its printhead. The geometry of a printhead orifice nozzle affects, for instance, the size, trajectory, and speed of ink drop ejection. In addition, the geometry of a printhead orifice nozzle affects the ink supply flow to the associated vaporization chamber and, in some instances, can affect the manner in which ink is ejected from adjacent nozzles. In practice, nozzle plates for inkjet printheads often are fabricated from nickel in an lithographic electroforming processes. One example of a suitable lithographic electroforming process is described in United States Patent No. 4,773,971, assigned to the Hewlett-Packard Company of Palo Alto, California. In the process described in the patent, nickel nozzle plates are formed with a reusable mandrel that includes a conductive material covered with a patterned dielectric layer. To form a nozzle plate, the reusable mandrel is inserted in an electroforming bath so that nickel is electroplated onto the conductive areas of the mandrel. An article entitled The ThinkJet Orifice Plate: A Part With Many Functions by Gary L. Siewell et al. in the Hewlett-Packard Journal, May 1985, pages 33-37, discloses an orifice plate made by a single electroforming step wherein nozzles are formed around pillars of photoresist with carefully controlled overplating. More particularly, the article discloses that a stainless steel mandrel is: (1) deburred, burnished, and cleaned; (2) a layer of photoresist is spun on the surface and patterned to form protected areas for manifolds; (3) the exposed surface is uniformly etched to a specified depth; (4) the resist is removed and the mandrel is burnished and cleaned again; (5) a new coat of photoresist is spun on and patterned to define the barriers and standoffs; and (6) the barriers and standoffs are etched. Further, the Siewell art discloses that the orifice plate can be made by: (1) laminating the stainless steel mandrel with dry film photoresist; (2) exposing and developing the resist so that circular pads, or pillars, are left for orifices or nozzles; (3) electroplating the mandrel with nickel on the exposed stainless steel areas including the insides of grooves etched into the mandrel to define the barrier walls and standoffs; (4) peeling the plating from the mandrel, the electroplated film being easily removed due to an oxide surface on the stainless steel which causes plated metals to only weakly adhere to the oxide surface; and (5) stripping the photoresist from the nickel foil. According to the article, the nickel foil has openings wherever the resist was on the mandrel. Still further, the article states that the resist is used to define edges of each orifice plate, including break tabs which allows a large number of orifice plates formed on the mandrel to be removed in a single piece, bonded to a mating array of thin-film substrates and separated into individual printheads. SUMMARY OF THE INVENTIONGenerally speaking, the present invention provides a continuous electroforming process and apparatus for manufacturing parts requiring precision micro-fabrication as specified in present claims 1 and 12 respectively. The process includes a first step of moving a surface of a mandrel having a reusable pattern thereon through an electroforming bath, a second step of depositing a metal layer on the surface of the mandrel in the shape of the pattern while the mandrel surface moves through the bath, and a third step of separating the metal layer from the mandrel surface after the metal layer has been deposited to a selected thickness. In practice, the mandrel can take various forms. For instance, the mandrel can be a movable belt. In an alternative embodiment, the mandrel can be a rotatable drum. When the mandrel is a movable belt, the belt can be made, for instance, of a sheet of polymer material such as polyimide having a metallized thin film such as titanium or chromium/titanium thereon forming the reusable pattern. Alternatively, the belt can comprise a sheet of electrically conductive material having a dielectric material such as silicon carbide, nitride or oxide thereon for defining the reusable pattern. When the mandrel is a drum, the drum can comprise an electrically conductive material such as stainless steel having a dielectric material thereon such as silicon carbide, nitride or oxide that define the reusable pattern. The electrically conductive material allows an electroplated layer of metal such as nickel to be built up thereon in the shape of the reusable pattern. Preferably, the reusable pattern is in the shape of a device having details in µm in height, width and depth dimensions. More particularly, the device comprises an orifice plate and the reusable pattern defines the plate's features by photolithography. BRIEF DESCRIPTION OF THE DRAWINGSThe present invention can be further understood by reference to the following description and attached drawings which illustrate the preferred embodiments. In the drawings: Figure 1 shows an apparatus useful for carrying out one embodiment of a process according to the invention; and Figure 2 shows a component of the apparatus shown in Figure 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTSIn the following, there will described a continuous electroforming process for manufacturing parts by precision micro-fabrication. The micro-fabricated parts can include, for example, orifice plates for printers, inkjet orifice plates, and masks for laser processing or for spectrophotometers. In the micro-fabrication process, the first step comprises moving a surface of a mandrel having a reusable pattern thereon through an electroforming bath. The second step comprises depositing a metal layer on the surface of the mandrel in the shape of the reusable pattern while the mandrel surface moves through the bath. The third step comprises separating the metal layer from the mandrel surface after the metal layer has deposited to a selected thickness. In practice, the mandrel can take various forms. For instance, in one embodiment, the mandrel is in the form of a movable belt. In another embodiment, the mandrel is in the form of a rotatable drum. Figure 1 shows an electroforming apparatus 1 wherein the mandrel 2 is in the form of a moving belt 3. (The belt 3 is shown by itself in Figure 2.) In the illustrated embodiment, the belt 3 moves through an electroforming bath 4 which includes an anode 5 such as a sacrificial nickel anode. In operation of the electroforming apparatus, current is applied between the anode 5 and the belt 3. As a result, the belt acts as a cathode, and a metal layer 6 is deposited onto it. In the embodiment shown in Figures 1 and 2, belt 3 is an endless belt supported for rotation in, for example, the counterclockwise direction. In this embodiment, belt 3 is supported by driven rollers 7 and 7a located outside the bath 4, while guides 8 are immersed in the bath 4. The deposited metal layer 6 is separated from the belt 3 outside the bath 4 at a location adjacent the intersection of a guide 9 and one of the driven rollers 7a. The separated metal layer 6a is then wound on a reel 10. With particular reference to the belt 3 in Figure 2, it should be noted that the belt includes details of a reusable pattern 11 having microfine dimensions. In the embodiment shown, the belt 3 includes a lower section which moves in a rectilinear path and the anode 5 is parallel to the rectilinear path and faces the lower section of the belt. When the mandrel is a movable belt, it can comprise a sheet of polymer material such as polyimide having a metallized thin film such as titanium or chromium/titanium thereon forming the reusable pattern. Alternatively, the belt can comprise a sheet of electrically conductive material having a dielectric material such as silicon carbide, nitride or oxide thereon for defining the reusable pattern on the electrically conductive material. Preferably, the belt is about 4 mile thick. Alternatively, the mandrel can be a drum comprised of an electrically conductive material such as stainless steel or other metals (including copper, brass, and steel coated with electroless nickel) having a dielectric material thereon (such as silicon carbide, nitride or oxide) for defining the pattern on the radially outer surface of the drum. In the case where the mandrel 2 is belt 3, the metallized thin film can be applied by process such as vacuum deposition. More particularly, in this case, the belt can comprise a layer of titanium on a sheet of polyimide. The polyimide material can be, for instance, KAPTON which is a product of DuPont or UPILEX which is a product of Ube Company of Japan. Alternatively, the metallized thin film can comprise a first layer of chromium which improves adhesion and a second layer of titanium. As still another alternative, the belt can be a layer of titanium on a polyimide sheet with a layer of dielectric material such as silicon nitride on the titanium layer. The dielectric material can be applied by, for instance, a process such as vacuum deposition. The belt can be fabricated in a number of ways. For instance, a thin metal film can be metallized on a polyimide substrate. The metallized film is preferably mirror polished to provide the highest quality parts when electroforming the metal layer on the belt. The reusable pattern 11 on the belt 3 can be defined by photolithography so as to provide a photoresist having a shape of the pattern 11 on the thin metal film. The thin metal film is etched such as by chemical etching, dry etching or plasma etching through to the polyimide substrate such that the thin metal film which remains after the etching has the shape of the photoresist. Then, the photoresist is removed to provide the belt 3 with the reusable pattern 11 thereon. Another way of making the belt is as follows. First, a sheet of polymer material such as polyimide is coated by a process such as by sputter depositing with a layer of electrically conductive material such as titanium or a first layer of chromium and a second layer of titanium over the chromium. Then, the electrically conductive material is coated with a layer of dielectric material such as silicon carbide, nitride or oxide. Then the reusable pattern 11 is defined by photolithography so as to provide a photoresist mask having a shape that defines the reusable pattern 11 on the dielectric layer. The dielectric layer is then etched such as by chemical etching, dry etching or plasma etching through to the electrically conductive material such that the dielectric layer which remains after the etching step has the shape of the photoresist. Then the photoresist is removed thereby providing the belt 3 with the pattern 11 thereon. The drum can be prepared in a similar manner. In particular, in the case where the drum is of stainless steel, the pattern 11 can be defined on the drum's outer periphery by photolithography. One advantage of this is that the insulating or dielectric material defines the pattern 11. In the above-described electroforming process, it is preferred that the deposited metal layer 6 is separated from the mandrel 2 outside the bath 4 after the deposited metal layer 6 has a selected thickness. To control the thickness of the deposited metal layer 6, adjustments can be made to the current applied between anode 5 and mandrel 2, or to the speed that the surface of the mandrel 2 moves through the bath 4. The bath 4 can comprise a nickel-Watts bath, a nickel-sulfamate bath or any other suitable bath. The anode can be a sacrificial anode or the deposited metal layer 6 can be obtained directly from the electrolyte forming the bath. In the case where a nickel-Watts bath is used, the bath can contain nickel chloride, nickel sulfate, boric acid and organic additives such as a leveler, a brightener and a stress reducer. When the above-described process is used to manufacture inkjet orifice plates, the pattern 11 on the mandrel can be used for forming inkjet orifice plates. Accordingly, the deposited metal layer 6 separated from the mandrel 2 will include a plurality of plates, each having the shape and features of an inkjet orifice plate with the plates being connected together in the form of a continuous sheet. The process can further include a step of bonding the plates to suitable thin-film substrates and a step of separating the bonded plates and substrates into individual printheads. The foregoing has described the principles, preferred embodiments and modes of operation of the present invention. However, the invention should not be construed as being limited to the particular embodiments discussed. Thus, the above-described embodiments should be regarded as illustrative rather than restrictive, and it should be appreciated that variations may be made in those embodiments by workers skilled in the art without departing from the scope of present invention as defined by the following claims. | A continuous electroforming process for forming a part requiring precision micro-fabrication such as an inkjet orifice plate, the process comprising: a first step of moving a surface of a mandrel (2) through an electroforming bath (4), said mandrel (2) comprising a sheet of electrically conductive material having a dielectric material thereon which defines a reusable pattern (11) on one side of the electrically conductive material, said reusable pattern being in the shape of a device having microfine dimensions in height, width and depth; a second step of depositing a metal layer (6) on the surface of the mandrel (2) while the surface of the mandrel (2) moves through the electroforming bath (4) until the metal layer (6) is deposited in the pattern (11) on the surface of the mandrel (2); and a third step of separating the metal layer (6a) from the surface of the mandrel (2) after the metal layer (6) is deposited in the second step. The process of claim 1, wherein the mandrel (2) comprises a moving belt (3). The process of claim 2, wherein the belt (3) comprises a sheet of polymer material having a metallized thin film thereon forming the pattern (11). The process of claim 3, wherein the metallized thin film comprises a layer of titanium. The process of claim 3, wherein the metallized thin film comprises a first layer of chromium and a second layer of titanium, the chromium layer being between the sheet of polymer material and the layer of titanium. The process of claim 1, wherein the mandrel (2) comprises a rotating drum (3). The process of claim 6, wherein the drum (3) comprises an electrically conductive material of stainless steel having a dielectric material thereon which defines the pattern (11). The process of one of claims 1 to 7, wherein the dielectric material is a material selected from the group consisting of silicon nitride, carbide and oxide. The process of one of claims 1 to 8, wherein the thickness of the metal layer (6) deposited in the second step is controlled by adjusting an applied current between the mandrel (2) and an anode (5) in the electroforming bath (4). The process of one of claims 1 to 9, wherein the thickness of the metal layer (6) deposited in the second step is controlled by adjusting a speed at which the mandrel surface moves through the electroforming bath (4). The process of claim 1, wherein the metal layer (6) applied in the second step comprises nickel. An apparatus (1) for electroforming a part requiring precision micro-fabrication such as an inkjet orifice plate, comprising: an electroforming bath (4); a mandrel (2) having a reusable pattern (11) on its one surface, the pattern (11) being defined by electrically conductive material which is covered by a dielectric material for defining said pattern in a shape of a device having microfine dimensions in height, width and depth; support means (7, 7a, 8, 9) supporting the mandrel (2) such that the mandrel surface moves continuously through the electroforming bath (4) during a step of electro-depositing metal from the electroforming bath (4) as a deposited metal layer (6) on the mandrel surface; separation means (7a, 9) for separating the deposited metal layer (6) from the mandrel (2); and reel means (10) for winding the deposited metal layer (6a) in a coil after it has been separated from the mandrel (2) by the separation means (7a, 9). The apparatus of claim 12, wherein the mandrel (2) comprises an endless belt (3) supported by the support means (7, 7a, 8, 9) such that a section of the belt (3) is immersed in an electrolyte comprising the electroforming bath (4). The apparatus of claim 13, wherein the endless belt (3) comprises a polymer sheet with the electrically conductive material on an outer surface of the endless belt (3). The apparatus of claim 12, wherein the mandrel (2) comprises a drum and the support means supports the drum for rotation such that part of the drum is immersed in an electrolyte comprising the electroforming bath (4). The apparatus of claim 15, wherein the drum is formed of metal, and a layer of dielectric material is provided on the drum for defining the pattern (11). The apparatus of one of claims 12 to 16, wherein the pattern (11) is shaped for forming a nozzle plate of an inkjet printhead for an inkjet printer. | HEWLETT PACKARD CO; HEWLETT-PACKARD COMPANY | LAM SI-TY; MCCLELLAND PAUL H; LAM, SI-TY; MCCLELLAND, PAUL H. |
EP-0490063-B1 | 490,063 | EP | B1 | EN | 19,980,429 | 1,992 | 20,100,220 | new | C07D207 | C07C255 | A01N43, C07C255, C07D207 | M07D207:34, C07D 207/34, C07C 255/13 | Process for the preparation of insecticidal, acaricidal and molluscicidal 2-halopyrrole-3-carbonitrile compounds | There is provided a process for the preparation of 2-halopyrrole-3-carbonitrile compounds (I) which are useful as insecticidal, acaricidal and molluscicidal agents. wherein X is Cl or Br. Furthermore, a process for the preparation of intermediates (II) is disclosed. wherein R is C₁-C₄ alkyl. | The present invention is directed to a process for preparing insecticidal, acaricidal and molluscicidal 2-halopyrrole-3-carbonitrile compounds of formula I wherein X is Cl or Br.According to Tetrahedron 45 (20), 6439-48(1989) such compounds have been obtained from a malodinitrile which in turn can be prepared in accordance with Chem. Berichte 113 (6), 2069-80 (1989).It is the problem of the invention to prepare the 2-halopyrrole-3-carbonitrile compounds in high yield. This problem is solved by the method of claim 1 or of claim 3.Surprisingly, it has been found that in compounds of formula I may be prepared in high yield by reacting malononitrile with the base and the haloacetaldehyde di(C1-C4 alkyl) acetal of formula II wherein R is C1-C4 alkyl and X is as described above in the presence of a solvent to obtain a (formylmethyl)malononitrile di(C1-C4 alkyl) acetal compound of formula III wherein R is as described above and reacting said formula III compound with a hydrogen halide acid.One of the preferred embodiments of the present invention involves reacting malononitrile with about 1 to 3 molar equivalents, of the base and about 1 to 3 molar equivalents, of a formula II haloacetaldehyde di(C1-C4 alkyl) acetal compound as described above in the presence of a solvent preferably at a temperature range of about 0°C to 100°C to form a formula III (formylmethyl)malononitrile di(C1-C4 alkyl) acetal compound as described above and reacting the formula III compound with at least 1 molar equivalent of hydrochloric acid or hydrobromic acid at a temperature range of about 15°C to 100°C to form 2-halopyrrole-3-carbonitrile compounds of formula I.The formula I compounds may be isolated by conventional techniques such as dilution of the reaction mixture with water and filtration or, alternatively, extraction with a suitable solvent. Suitable extraction solvents include water-immiscible solvents such as ether, ethyl acetate, toluene, methylene chloride and the like.Bases suitable for use in the process of the present invention include alkali metal C1-C6 alkoxides, alkali metal hydroxides, alkali metal hydrides, alkali metal carbonates, C1-C4 trialkylamines and pyridine. Preferred bases are potassium tert-butoxide, sodium methoxide and sodium hydride.Reaction solvents suitable for use in the present invention include organic solvents such as ether, tetrahydrofuran, ethylene glycol dimethyl ether, toluene and mixtures thereof. Preferred reaction solvents are tetrahydrofuran and ethylene glycol dimethyl ether.Starting formula II haloacetaldehyde di(C1-C4 alkyl) acetal compounds are prepared according to the procedures of Beilsteins Handbuch Der Organischen Chemie, Band I, System-Number 1-151, pages 611, 624 and 625, 1918.Molluscicidal 2,4,5-trihalopyrrole-3-carbonitrile compounds of formula IV may be prepared by halogenating formula I compounds using standard halogenating techniques. The reaction may be illustrated as follows: wherein X is Cl or Br and Y is Cl or Br.Preparation of N-substituted formula IV 2,4,5-trihalopyrrole-3-carbonitriles may be achieved by reacting the formula IV pyrrole with an alkylating or acylating agent in the presence of an alkali metal alkoxide or hydride. The reactions are illustrated as follows: wherein X is Cl or Br;Y is Cl or Br;Z is halogen; andR is C1-C6 alkyl optionally substituted with one to three halogen atoms, one cyano, one C1-C4 alkoxy, one C1-C6 alkylcarbonyloxy group, one C1-C6 alkoxycarbonyl group or one benzyloxy group.In order to facilitate a further understanding of the invention, the following examples are presented to illustrate more specific details thereof. The invention is not to be limited thereby except as defined in the claims. EXAMPLE 1Preparation of (Formylmethyl)malononitrile dimethyl acetalMalononitrile (20g, 0.30 mol) is added to a 0°C mixture of potassium tert-butoxide (37g, 0.33 mol), ethylene glycol dimethyl ether (300 mL) and tetrahydrofuran (75 mL). After a short time, bromoacetaldehyde dimethyl acetal (52g, 0.30 mol) is added to the reaction mixture. The reaction mixture is refluxed for 48 hours then cooled to room temperature. Solvent is removed and ether, water and brine are added to the reaction mixture. The organic layer is separated, dried over magnesium sulfate and concentrated invacuo to give a brown oil. Flash chromatography of the oil using silica gel and a 5:1 hexanes/ethyl acetate solution as eluant yields a colorless oil which is distilled to obtain the title compound as a colorless oil (10g; 21%, bp 110°-115°C, 3mmHg) which is identified by IR and NMR spectral analyses.EXAMPLE 2Preparation of 2-Chloropyrrole-3-carbonitrileHydrochloric acid (7 mL, 37%) is added to (formylmethyl)malononitrile dimethyl acetal (2g, 0.013 mol). The reaction mixture exotherms slightly to 33°-37°C where it stays for about 10 minutes. After another 20 minutes of stirring, a light colored solid precipitates. At this point, the reaction mixture is poured over an ice-water mixture and vacuum filtered. The resultant orange solid is dissolved in ethyl acetate and flash chromatographed using silica gel and 3:1 hexane/ethyl acetate as eluant to give the title compound as a white solid (0.7g, 43%, mp 105°-106°C) which is identified by IR and NMR spectral analyses.EXAMPLE 3Preparation of 2-Bromopyrrole-3-carbonitrileHydrobromic acid (5 mL, 47-49%) is added to (formylmethyl)malononitrile dimethyl acetal (0.55g, 0.0036 mol). After stirring for 30 minutes the reaction mixture is poured into an ice-water mixture and vacuum filtered. The solids are flash chromatographed using silica gel and 3:1 hexane/ethyl acetate as eluant to give the title compound as a beige solid (0.38g, 62%, mp 102°-106°C) which is identified by IR and NMR spectral analyses. | A process for the preparation of a 2-halopyrrole-3-carbonitrile compound having the structural formula wherein X is Cl or Br characterized by reacting malononitrile with 1 to 3 molar equivalents of a base selected from the group consisting of an alkali metal C1-C6 alkoxide, an alkali metal hydroxide, an alkali metal hydride, an alkali metal carbonate, a C1-C4 trialkylamine and pyridine and 1 to 3 molar equivalents of a haloacetaldehyde di(C1-C4 alkyl) acetal compound having the structural formula wherein R is C1-C4 alkyl and X is as described above in the presence of a solvent to obtain a (formylmethyl)malononitrile di(C1-C4 alkyl) acetal compound having the structure wherein R is as described above and reacting said (formylmethyl)malononitrile di(C1-C4 alkyl) acetal compound with at least 1 molar equivalent of hydrochloric acid or hydrobromic acid to form said 2-halopyrrole-3-carbonitrile compound. The process according to claim 1 wherein the base is selected from the group consisting of an alkali metal C1-C6 alkoxide, an alkali metal hydride and an alkali metal carbonate, and the solvent is selected from the group consisting of tetrahydrofuran, ether and ethylene glycol dimethyl ether.A process for the preparation of a 2-halopyrrole-3-carbonitrile compound having the structural formula wherein X is Cl or Br characterized by reacting a (formylmethyl)malononitrile di(C1-C4 alkyl) acetal compound having the structural formula wherein R is C1-C4 alkyl with at least 1 molar equivalent of hydrochloric acid or hydrobromic acid to form said 2-halopyrrole-3-carbonitrlle compound.The process according to claim 3 wherein the temperature of the reaction mixture is about 15° C to 100 °C. | AMERICAN CYANAMID CO; AMERICAN CYANAMID COMPANY | LOWEN GREGORY THOMAS; LOWEN, GREGORY THOMAS |
EP-0490065-B1 | 490,065 | EP | B1 | EN | 19,980,506 | 1,992 | 20,100,220 | new | C08L63 | C08K5 | C08K5, C08G59, C08L63 | C08G 59/40B4, C08K 5/5397+L63/00 | Fire retardant epoxy resin compositions | Thermosetting epoxy resin compositions having improved flame retardancy having combined therewith an effective amount of a dihydroxymethyl phosphine oxide having the general formula wherein R represents an alkyl group having from 1 to about 8 carbon atoms or -R'OH where R' represents an alkylene group having from 2 to about 8 carbon atoms, are disclosed. | Statement of the InventionThe present invention relates to thermosetting epoxy resin compositions which are rendered flame retardant by having combined therewith an effective amount of specific dihydroxymethyl phosphine oxides.Background of the InventionEpoxy resins and their utility are well known and have been described in numerous publications. Just as well known is the propensity of these resins to burn. To improve their flame retardant characteristics, epoxy resins have been compounded with phosphate and phosphonate esters including those containing haloalkyl groups as described in British Patent No. 1,487,609; U.S. Patent No. 3,192,242 and South African Patent No. 18201/77. The use of triphenylphosphine as a flame retardant additive for epoxy resins was described by Martin and Price, J. Applied Polymer Science, 12, 143-158 (1968).Tetrakishydroxymethylphosphonium chloride and trishydroxymethylphosphine oxide have also been used in epoxy resins as described in U.S. Patent No. 2,916,473. Aminoalkylphosphonic acid esters are suggested as fire retardant hardeners for epoxy resins in U.S. Patent No. 4,151,229.U.S. Patent Nos. 3,666,543 and 3,716,580 disclose 2-hydroxyalkylphosphine oxides and halogenated derivatives thereof that are said to have utility as flame proofing agents.U.S. Patent Nos. 4,345,059; 4,380,571 and 4,440,944 all disclose fire retardant epoxy resin compositions which contain 3-hydroxyalkylphosphine oxides to impart said fire retardant characteristics. Addition of halogenated organic compounds alone to epoxy resins for imparting flame retardancy is well known and widely practiced. The most widely used method is to add a brominated bis-phenol acetone or a bis-epoxide adduct thereof to the resin. However, these brominated resins, when used alone, require bromine contents of up to 20% or even higher to be effective. These large organobromine levels increase the density of the resin, generate large amounts of smoke containing corrosive materials such as hydrogen bromide gas, and may lead to generation of highly toxic materials such as polybrominated dibenzodioxins. Formulations which reduce the bromine content required for flame retardancy would thus have significant value.However, phosphorus based known flame retardant additives for use in epoxy resin compositions generally suffer from one or more deficiencies including low compatibility with the resin, low thermal stability or poor fire retardant behavior. Some fire retardant additives also negatively impact the glass transition temperature of the resin to an unacceptable extent.Summary of the InventionThe present invention is directed to thermosetting epoxy resin compositions having improved flame retardancy having combined therewith an effective amount of a dihydroxymethyl phosphine oxide having the general formula wherein R represents an alkyl group having from 1 to about 8 carbon atoms or -R'OH where R' represents an alkylene group having from 2 to about 8 carbon atoms.The present invention is also directed to a method of rendering epoxy resins fire retardant through the incorporation of the dihydroxyalkyl phosphine oxides of Formula I therein.In a further embodiment, the present invention is directed to epoxy laminate compositions containing the dihydroxyalkyl phosphine oxide of Formula I.Detailed Description of the InventionIn accordance with the present invention, it has been discovered that the addition of a relatively small but effective amount of a dihydroxyalkyl phosphine oxide having a structure as set forth in Formula I to an epoxy resin will substantially increase its resistance to burning. These fire retardant resins also exhibit excellent handling characteristics including glass transition temperatures (Tg's). Further, even upon burning, such resins evolve substantially reduced quantities of smoke than do many other fire retardant epoxy resin compositions.The dihydroxyalkyl phosphine oxides of Formula I may be used with either conventional hardeners, such as amine or anhydride hardeners, and they may also be used alone or in combination with halogen-containing epoxide resins, such as bromine-containing resins. When the epoxide resin is heat cured in the presence of the dihydroxyalkyl phosphine oxide and a hardener, the dihydroxyalkyl phosphine oxide is believed to react with the hardener and/or terminal epoxy groups to become incorporated in the polymer molecule.The dihydroxyalkyl phosphine oxides useful in the practice of the present invention are those represented by the general formula wherein R represents an alkyl group having from 1 to about 8 carbon atoms or the group -R'OH wherein R' represents an alkylene group having from 2 to about 8 carbon atoms. Preferred are compounds of Formula I wherein R represents alkyl groups having from 1 to about 4 carbon atoms and R1 represents an alkylen group having 2 to about 4 carbon atoms.Particularly effective in increasing the fire resistance of epoxy resins, and especially preferred in the practice of the present invention are: isobutyl-bis(hydroxymethyl)phosphine oxide, t-butyl-bis(hydroxymethyl)phosphine oxide, methyl-bis(hydroxymethyl)phosphine oxide, and mixtures thereof.The dihydroxymethyl phosphine oxides useful in the practice of the present invention may be conveniently prepared by reacting a monoalkyl phosphine with two equivalents of formaldehyde in an aqueous solution with control of the pH of said solution followed by oxidation with a stoichiometric amount of hydrogen peroxide.Although any of the known hardeners for epoxy resins may be used in conjunction with the phosphine oxide flame retardant additives, the amine and anhydride hardeners are particularly preferred. The phosphine oxides may, if desired, be reacted with a typical cyclic dicarboxylic acid anhydride such as phthalic anhydride, nadic methyl anhydride, etc., to form an intermediate ester which will further react in an epoxy resin system to produce a cured flame retardant object. Alternatively, the phosphine oxides may be reacted with the epoxy resin monomers such as epichlorohydrin with elimination of hydrochloric acid to give a glycidyl ether derivative. Such intermediates would have excellent compatibility with epoxy resins and minimize the reaction between the hardener and the phosphine oxide. Alternatively, the phosphine oxides may be mixed with or partially reacted with the uncured epoxy resins followed by addition of the hardener, anhydrides or amines to cure the resin.Other suitable hardeners for the claimed epoxy resins are the aromatic amines such as methylene dianiline or other amines such as dicyandiamide or other higher temperature curing agents such as 4,4' diaminodiphenyl sulfone, or BF3-monoethylamine complex.The particular epoxy resin and the specific hardener that is used are not critical as the phosphine oxides herein described will react with all of the known epoxy resins. The hardeners employed need not be limited to those mentioned above as all hardeners common to epoxy resin technology may be used to obtain the fire retardant epoxy resins of the present invention.It should also be understood that if the functionality of the epoxy resin and/or the phosphine oxide and/or the hardener is three or greater, crosslinking may occur with the production of infusable molded objects whereas when the functionality of the phosphine oxide, epoxy resins and anhydride or amine is two or less, thermoplastic resins are obtained.Mixtures may be prepared of the phosphine oxides and hardeners prior to addition of the epoxy resin monomer. Such phosphine oxide-hardener intermediate may be prepared by heating the phosphine oxide with, for example, anhydrides at a temperature between 70oC and 120oC until a solution forms. Mixed anhydrides, such as mixtures of phthalic anhydride and nadic methyl anhydride, in all proportions may be used. The phosphine oxide may be present in amounts such that the phosphorus content of the resin is up to 5% by weight or more in the final resin formulation but is preferably present in amounts from about 0.01% to about 5% by weight based upon the weight of epoxide present. Most preferably, the phosphine oxide additives are present in amounts such that the phosphorus content of the resin ranges from 0.05 to about 2.0% by weight based upon the final resin formation. When anhydrides are used as the hardener, stoichiometric amounts are preferred, i.e. the ratio of the moles of dibasic anhydride to the equivalents of epoxide is desirably from about 0.80 to about 1.2. Optimally, the ratio of the moles of anhydride to the equivalents of epoxide is between about 0.90 and about 1.0.In those cases where the solubility of the phosphine oxide flame retardants in the epoxy resin monomers is not a problem, the phosphine oxides can be mixed with the epoxy resin first, an anhydride hardener first, or all three components can be mixed at once. The phosphine oxides were found to have an accelerating effect upon the cure of epoxy resins such that no additional accelerators are required.The resin mixtures herein described may be cast into sheets by heating in molds consisting of mylar-lined glass plates with teflon spacers. Fillers may be added to the resin-phosphine oxide mixtures which can then be compression, transfer or injection molded. The epoxy resin mixtures of the present invention can also be used as laminating resins using either dry molding or wet lay-up techniques. The preferred substrate is glass cloth but a woven or non-woven fabric or sheets of cellulose may be substituted for the glass cloth to obtain a laminate having different physical and electrical properties. Such epoxy resins can be used in any application involving epoxy resins but are most suited for electrical applications including laminated printed circuit boards, potting compounds, castings, encapsulations, molding powders, etc. The claimed phosphine oxide-epoxy resin compositions may also be used as coatings, sealants or adhesives, and can be used with or without fillers and other additives. It is believed the physical and electrical properties of those epoxy resins cured in the presence of phosphine oxide additives are substantially unchanged from those epoxy resins containing no additives. With the proper formulation and curing temperature, such variations, as do exist, may be further minimized.The phosphine oxides described herein may be used as the sole flame retardant in epoxy resins or may be used in combination with halogen-containing flame retardants. Mixtures of these materials with other previously described phosphorus based epoxy flame retardants could also be used. Especially effective are mixtures containing the phosphine oxide flame retardants in combination with a brominated bisphenol A based resin such as the diglycidyl ether of tetrabromobisphenol A (manufactured by the Shell Chemical Company of Houston, Texas as EPON® 1120). Preferably such resins may be present in amounts ranging from about 1-80 wt.% based upon the weight of the final resin composition. Most preferably, such resins are present in amounts ranging from 25-50 wt.% based upon the same basis.The following Examples are intended to illustrate some of the more preferred aspects of the present invention and, accordingly, should not be considered as necessarily limiting the scope of the invention. All parts are expressed in parts by weight unless otherwise specified.ExamplesDefinitions1. IBHMPO shall represent isobutyl-bis(hydroxymethyl)phosphine oxide. 2. TBHMPO shall represent t-butyl-bis(hydroxymethyl)phosphine oxide.3. MHMPO shall represent methyl-bis(hydroxymethyl)phosphine oxide.4. THMPO shall represent tris(hydroxymethyl)phosphine oxide, which is contained herein for the purposes of comparison.5. BHPPO shall represent sec-butyl-bis(3-hydroxypropyl)phosphine oxide, which is contained herein for the purposes of comparison.6. IBHPPO shall represent isobutyl-bis(3-hydroxypropyl)phosphine oxide, which is contained herein for the purposes of comparison.7. ABT represents the average burn time for a laminate of an epoxy resin and determined by averaging the burn times from UL-94 tests run on five identical samples of a given laminate.8. UL-94 represents a rating under the procedure set forth in UL-94 procedure of Underwriters Laboratories, Inc. for evaluating the flammability of vertically aligned plastic materials. The procedure involves the initial contacting of a flame of specified height to a plastic article for 10 seconds. If the burning plastic extinguishes itself within 30 seconds after removal of the flame, the elapsed time is recorded and the test is then repeated. Failure to self-extinguish within to the 30 second period during either the first or second trial is equated to failure of the flame retardant characteristics of the plastic. The performance of the plastic is rated on a scale consisting of the designations V-O , V-1 and V-2 . V-O denotes that neither burn time exceeded 10 seconds. V-1 denotes that neither burn time exceeded 30 seconds.9. Tg shall mean glass transition temperature. It is determined by dynamic mechanical analysis (DMA), and the tangent delta value is reported in degrees centigrade.PROCEDUREA resin formulation was prepared using various quantities of EPON® 828 resin and EPON® 1120 resin, (both products Shell Chemical Company). EPON 1120 resin is a brominated bisphenol A resin which is said to contain about 20 weight % of bromine. To said resins were added 6 phr of DICY, 0.45 phr of benzyl dimethyl amine accelerator and 50 phr of methyl cellusolve solvent. Also added were the phosphine oxide flame retardant additives set forth in the above Definitions.Following complete mixing of the above formulation in a glass jar at 50°C the formulation was coated onto a 9.5 x 15.5 piece of glass cloth (produced by the Clark Schwebel Company and marketed under designated 7642/CS700). The coated glass fiber was then heated to 160oC for about 7 minutes in a forced draft oven. The fiber, now a non-tacky prepreg, was then cut into nine (9) 3 x5 strips which were stacked upon one another (4 up, 5 down) with an aluminum plate coated with releasing fabric on the outer sides thereof. The stack was then placed on a press. The stacked strips were then subjected to elevated temperatures and pressures according to the following general schedule: 10 minutes at 120oC with no pressure applied.45 minutes at 200°C with applied pressure of about 200 psi.It should be noted that the application of heat and pressure was varied slightly sample to sample in order to control resin flow of the laminate. This was done by varying the time period that the laminate was held at 120oC without application of pressure.The press and laminate were then cooled. Upon removal from the press, the laminates appeared light green/translucent in color with varying amounts on resin adhering to the edges thereof. A laminate was then weighed, its thickness measured and its percent resin content determined. The laminate was then cut into five strips (0.5 x5 ) for use in conducting the previously described UL-94 test. The data gathered in this test is set forth in Table 1. Example% P%BrAdditive%ResinUL-94 RatingABT (Sec.)1020---43V-01.42018---41V-00.83016---42V-04.34014---42V-1145012---44V-1226010---42fails---71.09IBHMPO39V-00.280.89IBHMPO41V-03.990.511IBHMPO42V-01.9100.610IBHMPO41V-13.7110.515IBHMPO30V-00.4120.511IBHMPO25V-00.4130.59IBHMPO31V-19140.713IBHMPO25V-00150.79IBHMPO32V-01.2160.77IBHMPO38V-1 16.2170.811 IBHMPO 36 V-0 1.2180.87IBHMPO28V-03.0190.85IBHMPO34fails27.4201.09IBHMPO33V-01.0211.07IBHMPO28V-110.2221.05IBHMPO30V-115230.88TBHMPO35V-18.8243.00TBHMPO44fails---253.00TBHMPO46V-122.4260.810TBHMPO39V-03.3270.610MHMPO37V-17.5281.010MHMPO41V-02.1290.610THMPO31V-03.4300.610THMPO36V-02.4310.87IBHPPO43fails23320.810IBHPPO32V-18.0330.87BHPPO35V-115.6340.810BHPPO36V-16.0The data above demonstrates that the claimed resin compositions exhibit flame retardant properties even when such compositions do not contain bromine therein. However, superior results are achieved wherein bromine is indeed present in such compositions.The glass transition temperatures of several resins produced in the course of the preceding Examples were determined. The results are set forth in Table 2 below. Tg data for resins not containing flame retardant additives were also determined. Resins containing 10% and 20% bromine possessed Tg's of 143 and 137, respectfully. Example No.% P% BrAdditiveTg230.88TBHMPO147253.00TBHMPO131270.610MHMPO145290.610THMPO144320.810IBHPPO131340.810BHPPO133110.515IBHMPO142100.610TBHMPO141260.810TBHMPO141281.010MHMPO142The above data shows that the claimed flame retardant resin compositions possess Tg's comparable to those of resin compositions which do not contain flame retardant additives. Moreover, the claimed resin compositions are further shown to possess higher Tg's than those of flame retardant compositions of the prior art. The composition containing THMPO has a similar Tg to the compounds of the invention but is insoluble in the resin varnish and significantly increases the gel time of the resin (Kofler hot bench method). | An epoxy resin composition having flame retardant properties comprising an epoxy resin, a hardener and an effective amount of at least one dihydroxymethyl phosphine oxide of the formula wherein R represents an alkyl group having from 1 to 8 carbon atoms or the group R'OH wherein R' represents an alkylene group having from 2 to 8 carbon atoms.The resin composition of Claim 1 wherein R is an alkyl group having from 1 to 4 carbon atoms and R' is an alkylene group having from 2 to 4 carbon atoms.The resin composition of Claim 1 wherein the dihydroxymethyl phosphine oxide is selected from the group consisting of isobutyl-bis(hydroxymethyl)phosphine oxide, t-butyl-bis(hydroxymethyl)phosphine oxide, methyl-bis(hydroxymethyl) phosphine oxide, and mixtures thereof.The resin composition of Claim 1 wherein the dihydroxymethyl phosphine oxide is present in quantities wherein the phosphorus content contributed ranges from 0.01 to 5% by weight based upon the weight of the resin composition.The resin composition of Claim 4 wherein the dihydroxymethyl phosphine oxide is present in quantities wherein the phosphorus content contributed ranges from 0.05 to 2% by weight based upon the weight of the resin composition.The resin composition of Claim 1 further comprising from 1.0 to 30% by weight of bromine based upon the weight of the resin composition.The resin composition of claim 6 further comprising from 2 to 11% by weight of bromine based upon the weight of the resin composition.A process for the production of an epoxy resin composition having flame retardant properties comprising reacting an epoxy resin, a hardener and an effective amount of at least one dihydroxymethyl phosphine oxide of the formula wherein R represents an alkyl group having from 1 to about 8 carbon atoms or the group R'OH wherein R' represents an alkylene group having from 2 to about 8 carbon atoms.The process of Claim 8 wherein R is an alkyl group having from 1 to 4 carbon atoms and R' is an alkylene group having from 2 to 4 carbon atoms.The process of Claim 9 wherein the dihydroxymethyl phosphine oxide is selected from the group consisting of isobutyl-bis(hydroxymethyl)phosphine oxide, t-butyl-bis(hydroxymethyl)phosphine oxide, methyl-bis(hydroxymethyl) phosphine oxide, and mixtures thereof. The process of Claim 8 wherein the dihydroxymethyl phosphine oxide is present in quantities wherein the phosphorus content contributed ranges from 0.01 to 5% by weight based upon the weight of the resin composition.The process of Claim 11 wherein the dihydroxymethyl phosphine oxide is present in quantities wherein the phosphorus content contributed ranges from 0.05 to 2% by weight based upon the weight of the resin composition.The process of Claim 8 further comprising from 1.0 to 30% by weight of bromine based upon the weight of the resin composition.The process of Claim 13 further comprising from about 2 to 11% by weight of bromine based upon the weight of the resin composition.A product produced through the process of Claim 8. | CYTEC TECH CORP; CYTEC TECHNOLOGY CORP. | CALBICK CHESTER J; FISCHER ROBERT G JR; CALBICK, CHESTER J.; FISCHER, ROBERT G., JR. |
EP-0490069-B1 | 490,069 | EP | B1 | EN | 19,980,121 | 1,992 | 20,100,220 | new | G11B25 | G11B21, G11B33, G11B19 | G11B25, G11B19, G11B23, G11B5, G11B33, G11B17 | G11B 19/00, G11B 33/14C, G11B 25/04R, G11B 23/03A10, G11B 5/55D, G11B 19/20, G11B 17/043 | Magnetic disk drive | A cartridge (234) for accommodating a magnetic recording medium (222) also accommodates an actuator (225) and a spindle (232). The spindle (232) accommodated in the cartridge (234) is driven by a spindle driving mechanism (236) provided in a driving device (235) so as to rotate the magnetic recording medium (322). The actuator (225) is driven by an actuator driving mechanism (237) provided in the driving device (235) so as to move a magnetic head approximately in the radial direction of the magnetic recording medium (222). The cartridge (234) includes a shutter mechanism (241) which is opened so as to expose at least a part of the spindle (232) and the actuator (225) in such a manner as to face the actuator driving mechanism (237) and the spindle driving mechanism (236), respectively, when the cartridge (234) is mounted on the driving device (235) and which is closed so as to enclose the spindle (232) and the magnetic head and the actuator (225) in the cartridge (234) in a sealed state when the cartridge (234) is removed from the driving device (235). The cartridge (234) further includes a ramp loading mechanism (229) for protecting the magnetic head from an external shock when the cartridge (234) is removed from the driving device (235). | The present invention relates to a magnetic disk drive which is used as an external storage unit of a computer.Fig. 8 is a perspective view of an example of a conventional magnetic disk apparatus, which is shown in a catalogue of a microfloppy disk drive (3.5-inch flexible disk drive: MP-F11W) produced by SONY Corporation. This is a very general 3.5-inch flexible disk device (hereinunder referred to as FDD ). In Fig. 8, the reference numeral 1 represents a magnetic head, 2 an arm to which the magnetic head 2 is fixed such that the magnetic head 2 exists within a predetermined azimuth, 3 a carriage to which the magnetic head 1 on the opposite side is fixed such that the magnetic head 2 exists within a predetermined azimuth, 4 a pressure spring for applying a predetermined pressure to the magnetic head 1 through the arm 2, 5 a fitting metal for fixing the pressure spring 4 to the carriage 3, 6 a lead screw which axially rotates and induces the linear reciprocal movements of the carriage 3, 7 a stepping motor for applying a driving force to the lead screw 6 and 8 a flexible printed circuit (hereinunder referred to as FPC ). The reference numeral 9 denotes a loading mechanism having a function of mounting and removing a cartridge which is shown in Fig. 9, 10 a base to which various structures are fixed so as to be accommodated therein, 11 a front panel which is attached to the front surface of the disk drive, 12 a door provided on the front panel 11 so as to be opened and closed when the cartridge 18 is mounted or removed, 13 a push button which is pressed into the apparatus or released coupled with the movement of the loading mechanism 9, 14 a printed circuit board which is fixed to the bottom portion of the base 10, and 15 a mounting frame for mounting the drive on a system such as a personal computer.Fig. 9 is a perspective view of the cartridge 18. The reference numeral 16 represents a flexible recording medium on and from which information is written or read by the magnetic heads 1, 17 a shutter which is opened or closed coupled with the movement of the loading mechanism 9 so as to expose or cover the portion of the recording medium 16 with which the magnetic head 1 comes into contact, 19 a chucking plate magnetically attracted to the rotary portion of a spindle motor (not shown) which is provided in the disk drive shown in Fig. 8, 20 a center hole for receiving the centering shaft of the spindle motor and 21 a driving hole into which the driving pin of the spindle motor is inserted and to which the driving force is transmitted. The operation of this conventional magnetic disk drive will now be explained.When the cartridge 18 shown in Fig. 9 is inserted from the door 12 of the front panel 11, the shutter 17 is slid in the direction indicated by the arrow A in Fig. 9 by the loading mechanism 9, thereby exposing the portion with which the magnetic head 1 comes into contact. At the same time, the chucking plate 19 is attracted to the spindle chucking surface by the magnetic force of a magnet provided on the spindle chucking surface.The push button 13 projects coupled with the movement of the loading mechanism 9. The arm 2 is pushed down by the pressure spring 4 and the magnetic head 1 fixed on the arm 2 comes into contact with the recording medium 16, whereby the recording medium 16 is sandwiched between the magnetic head 1 fixed on the arm and the magnetic head 1 fixed on the carriage 3. When the recording medium 16 is normally chucked, the spindle motor starts to rotate, and the driving pin of the spindle motor comes into the driving hole 21 provided in the chucking plate 19, so that the recording medium 16 also rotates. The rotation of the stepping motor 7 is transmitted to the carriage 3 through the lead screw 6 and the carriage 3 linearly reciprocates by the distance which is proportional to the rotational angle of the stepping motor 7, so that the magnetic head 1 is positioned at the desired track position of the recording medium 16 in accordance with the command from the system.When the positioning of the magnetic head 1 is finished, the magnetic head 1 starts to write or read information on or from the magnetic recording medium 16. When the user presses the push button 13 in order to take out the cartridge 18 after the end of the writing/reading of necessary information, the loading mechanism 9 operates the other way around. That is, the arm 2 is pushed up, and the cartridge 18 is pushed out of the door 12 of the front panel 11. This FDD operates in the same way with respect to any other recording medium 16. In addition, in order to enable the recording medium 16 to operate normally in any other disk drive, namely, to impart compatibility between drives to the recording medium 16, the magnetic head 1 is fixed to the arm 2 within a predetermined azimuth in any disk drive. An FDD as a conventional magnetic disk drive in which a recording medium is replaceable has the above-described structure. Such an FDD must be free from the non-uniformity in the chucking accuracy at which a recording medium is chucked by the spindle and the non-uniformity in the rotational accuracy due to the non-uniformity in the chucking accuracy so as to write and read information on and from any recording medium in the same way. For this reason, the FDD must have a compatibility between recording mediums and impart a compatibility between drives to a recording medium. If these demands are satisfied, the increase in the recording density is checked and it is difficult to reduce the size of the disk drive in spite of a small capacity. In addition, since the disk drive does not have a sealed structure so as to make a recording medium replaceable, the dust which has entered the apparatus goes between the magnetic head and the recording medium and damages the recording medium or adheres to the driving mechanism such as the lead screw, thereby deteriorating the positioning accuracy and lowering the reliability. WO 90/05974 already discloses a magnetic disk drive including a spindle motor assembly having a magnetic clutch plate and an actuator. The disk drive receives a hermetically sealed cartridge containing a plurality of disks with associated heads mounted in the cartridge. Associated with an arm assembly which supports the heads is a component for use with the actuator. With the cartridge inserted in the drive, the actuator operates to cause the heads to traverse relative to the disk as the spindle motorassembly uses a magnetic field to engage a magnetic plate associated with the cartridge in order to spin the disk. Data transfer connectors are associated with both the drive and the cartridge in order to allow for the transfer of data between the cartridge and the drive. However, the cartridge has not a completely sealed structure, because part of the arm assembly projects via an opening of the cartridge. Through this opening dust may enter into the cartridge, which can cause the magnetic head to crash.JP-A-61074188 shows a disk cartridge including a case. In order to prevent the entry of dust or corrosive atmosphere into the case, it is closed at the side opposite to the insertion port of a drive shaft and simultaneously a flexible seal member is disposed on the interior of the insertion port forming case.JP-A-2139781 describes a magnetic disk device comprising means for reducing noise. Since vibration caused by a driving mechanism for a spindle and an access mechanism is transmitted to a base of a head disk assembly, a sound absorbing material is arranged on the outer surface of the base. From JP-A-2 094 192 a magnetic disk device is known which comprises a base plate for housing a carriage including the magnetic heads, and spindle and magnetic disks in a sealed state. In order to electromagnetically shield the magnetic disk device from external electromagnetic noise and also to prevent leakage of a magnetic flux from the device, the inner surface of the base plate is coated with a magnetic substance. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to solve the above-described problems in the related art and to provide a magnetic disk drive which allows the replacement of a recording medium, which has high reliability. For solving this object, a magnetic disk drive as known from WO 90/05974 comprises the features of the characterizing part of claim 1. Preferred embodiments of the magnetic disk drive according to the present invention are defined in the subclaims. In this structure according to the invention, the loading mechanism opens and closes the shutter mechanism when the cartridge is mounted on the driving device and removed therefrom, respectively. The loading mechanism opens the shutter mechanism when the cartridge is mounted on the driving device and exposes at least a part of the actuator and the spindle in the cartridge. In this state, the spindle driving mechanism and the actuator mechanism drive the spindle and the actuator, respectively. When the spindle is driven, the magnetic recording medium rotates and when the actuator is driven, the magnetic head is positioned. In this state, it is possible to write desired information at a given position on the magnetiv recording medium by the magnetic head or to read from a given position on the recording medium by the magnetic head the information written at that position. On the other hand, when the cartridge is removed from the driving device by the loading mechanism, the loading mechanism closes the shutter mechanism. In other words, the cartridge assumes a sealed state.In this way, according to the present invention, a small-sized magnetic disk drive which has higher reliability and a high recording density is realized at a low cost while maintaining easiness in handling. These advantages are ascribed to the fact that since the cartridge has a sealed structure, the cartridge is unsusceptible to dust and the recording density is enhanced, and that since the number of elements which are to be disposed in the cartridge in a sealed state is small, it is possible to reduce the size of the cartridge.The above and other objects, features and advantages of the present invention will become clear from the following description of the preferred embodiments thereof, taken in conjunction with the accompanying drawings. Fig. 1 is perspective view of an embodiment of a magnetic disk drive according to the present invention;Fig. 2A is a plan view of the embodiment shown in Fig. 1;Fig. 2B is a B-B sectional side elevational view of the embodiment shown in Fig. 2A; Fig. 3A is a plan view of the bottom of the cartridge in the embodiment shown in Fig. 1, in the state in which the shutter mechanism is open;Fig. 3B is a plan view of the bottom of the cartridge of the embodiment shwon in Fig. 1, in the state in which the shutter mechanism is closed;Fig. 4 is a perspective view of the actuator in the embodiment shown in Fig. 1;Figs. 5A and 5B are a sectional side elevational view and a plan view, respectively, of the spindle in the embodiment shown in Fig. 1;Figs. 5C and 5D are a sectional side elevational view and a plan view, respectively, of the spindle driving mechanism in the embodiment shown in Fig. 1;Fig. 6 shows another embodiment of a magnetic disk drive according to the present invention;Fig. 7 is a perspective view of the actuator and the actuator driving portion in a conventional magnetic disk drive shown in Fig. 8;Fig. 8 is a perspective view of the conventional magnetic disk drive; andFig. 9 is a perspective view of the cartridge in the conventional magnetic disk drive.An embodiment of the present invention will be explained hereinunder with reference to the accompanying drawings.Fig. 1 is a perspective view of an embodiment of the present invention. The reference numeral 232 represents a spindle on which a recording medium 222 of substantially not more than 76 mm mounted and which rotates with high accuracy, 233 a moving magnet fixed to one end of an actuator 225 which is opposite to the end at which a suspension 224 is fixed, and 234 a cartridge composed of a cover 230 and a base 210 and accommodating various elements therein. The cartridge 234 has a height of about less than 10 mm, a width of about less than 70 mm and a length of about less than 106 mm. The reference numeral 235 denotes a driving device into which the cartridge 234 is integrally inserted, and 236 a spindle motor driving mechanism which is composed of a plurality of flat coils 236a and which is disposed in the driving device 235 at the position which opposes the bottom portion of the spindle 232.The reference numeral 237 represents an actuator driving mechanism disposed in the driving device 235 at the position which opposes the bottom portion of the actuator 225, 238 a slot cover for covering the upper portion of the driving device 235 in the state in which the cartridge 234 is inserted thereinto, 239 a slot door provided at one end of the slot cover 238 so as to be opened and closed when the cartridge 234 is inserted or removed, 240 a loading mechanism provided in the driving device 235 so as to mount and remove the cartridge 234 on and from the driving device 235, 240a an L-shaped end portion of the loading mechanism 240, 240b the other end portion of the loading mechanism 240 and 241 a shutter mechanism which is composed of a magnetic shielding material and which slides so as to expose or cover the bottom portion of the actuator 225 and the bottom portion of the spindle 232 coupled with the operation of mounting or removing the cartridge 234.The reference numeral 242 represents a positioning pin A provided on the driving device 235 so as to determine the position of the cartridge 234 when the cartridge 234 is inserted, 243 a positioning pin B provided on the driving device 235 similarly to the positioning pin A 242, and 244 a connector A which is provided in the driving device 235 so as to come into contact with a connector B 245 (shown in Fig. 3A) in electric conduction which is provided on the bottom portion of the cartridge 234 in electrical connection with an FPC 208 which transmits a signal of a magnetic head 223.The reference numeral 246 represents a system connector which is attached to a printed circuit board 214 at one end of the driving device 235 so as to connect the driving device 235 to the system. In Fig. 3A, the reference numeral 253 denotes a retracting cam A which is provided on the bottom surface of the cartridge 234 and which is rotated by means of a spring or the like. The reference numeral 254 in Fig. 1 represents a retracting cam B which is provided in the cartridge 234 and which has the same rotational shaft as the retracting cam A 253. The reference numeral 226 denotes a pivot and 229 a ramp loading mechanism.Fig. 2A is a plan view of the embodiment shown in Fig. 1 in the state in which the cartridge 234 is integrally inserted into the driving device 235 and Fig. 2B is a sectional side elevational view thereof. In Figs. 2A and 2B, the reference numeral 247 represents a spindle housing which constitutes a bearing of the spindle 232, 248 a subbase to which the spindle housing 247 and a bearing portion 225a of the actuator 225 are fixed, 249 a subplate to which the subbase 248 is fixed through a column 252, 250 a buffer material with which the gap between the subbase and the inner wall of the cartridge 234 and the gap between the subplate 249 and the inner wall of the cartridge 234 are filled.The reference numeral 251 represents a rotor which constitutes the bottom portion of the spindle 232. The rotor 251 is composed of a magnet which has a plurality of magnetic poles in the circumferential direction in correspondence with number of the flat coils 236a of the spindle driving mechanism 236. The reference numeral 255 in Fig. 4 denotes a yoke which constitutes the moving magnet 233, 256 a pair of magnets fixed to both ends of the yoke 255, and 257 a coil wound around the actuator driving mechanism 237 in a flat shape. The reference numeral 213 represents a push button and 223 the magnetic head in Figs. 2A and 2B. Figs. 3A and 3B show the cartridge 234 and Fig. 4 shows the structure of the actuator 225 and the vicinity thereof. Figs. 5A to 5D show the structure of the spindle 232, the spindle motor driving mechanism and the vicinity thereof.The operation of this magnetic disk drive will now be explained. When the user pushes the cartridge 234 into the slot cover 238 while pressing the cartridge 234 against the slot door 239 in the direction indicated by the arrow A in Fig. 1, the slot door 239 swivels inwardly and downwardly around the axis B to clear the entrance. The cartridge 234 is then inserted into the slot cover 238 along the L-shaped end portions 240a of the loading mechanism 240 with the slot door 239 pressed under the cartridge 234 until the cartridge 234 abuts against the positioning pin A 242 and the positioning pin B 243 and is stopped thereby. Simultaneously, the loading mechanism 240 is lowered, and the cartridge 234 is also lowered by virtue of the L-shaped end portions 240a, thereby being united with the driving device 235 into one body.When the cartridge 234 is inserted, the end portions 240b of the loading mechanism 240 slide the shutter mechanism 241 in the opposite direction to the direction of cartridge insertion in correspondence with the amount of horizontal movement of the cartridge 234. As a result, the shuttering mechanism 241 exposes a part of the actuator 225 in the vicinity of the moving magnet 233 and a part of the spindle 232 in the vicinity of the bottom portion of the rotor 251, both of which have been covered by the shutter mechanism 241 on the base 210, and the connector B 245, as shown in Fig. 3A.In this way, the cartridge 234 is united with the driving device 235 into one body with the bottom portion of the rotor 251 of the spindle 232 facing the spindle motor driving mechanism 236, and the magnetic poles of the pair of magnets 256 of the moving magnet 233 facing the actuator driving mechanism 237. In this state, the connector A 244 of the driving mechanism 235 comes into contact with the connector B 245 of the cartridge 234 and they are electrically connected with each other. When a command such as writing and reading is transmitted from the system to the driving device 235 through the system connector 246, a current flows to the spindle driving mechanism 236 in accordance with the command, so that the spindle 232 is rotated by the electromagnetic induction produced between the spindle driving mechanism 236 and the rotor 251.When the number of revolutions of the spindle 232 reaches a stationary number of revolutions and the spindle 232 rotates normally, a control current flows to the actuator driving mechanism 237, and the electromagnetic induction by a magnetic circuit constituted by the actuator driving mechanism 237 and the moving magnet 233 produces the force for moving the moving magnet 233. As a result, the actuator 225 with the suspension 224 mounted on the ramp loading mechanism 229 rotates around the pivot 226, so that the suspension 224 leaves the ramp loading mechanism 229 and the magnetic head 223 moves to the outer periphery of the recording medium 222 while floating thereabove at a slight height.In this state, it is possible to rock the actuator 225 by varying the direction of the current flow, and it is possible to position the magnetic head 223 at a desired position on the recording medium 22 for the writing/reading operation by controlling the amount of current. The written/read signal is transmitted to the connector A 244 through the FPC 208, and to the connector B 245 which is electrically connected to the connector A 244. The signal is then subjected to a predetermined processing by the printed circuit board 214 provided on the bottom portion of the driving device 235 and transmitted to the system through the system connector 246.The operation of removing the cartridge 234 from the driving device 235 after the end of a predetermined operation will now be explained. When the push button 213 is pressed, the loading mechanism 240 is raised and the cartridge 234 is also raised therewith. The connecter A 244 is separated from the connector B 245, whereby the bottom portion of the rotor 251 of the spindle 232 is moved from position which faces the spindle motor driving mechanism 236 and the magnetic poles of the pair of magnets 256 of the moving magnet 233 are moved from the position which faces the actuator driving mechanism 237. In this state, it is possible to remove the cartridge 234 from the driving device 235.When the cartridge 234 is drawn, the shutter mechanism 241 slides in the opposite direction to the direction of cartridge removal in correspondence with the amount of horizontal movement of the cartridge 234. The shutter mechanism 241 thus covers the part of the actuator 225 in the vicinity of the moving magnet 233, the part of the spindle 232 in the vicinity of the bottom portion of the rotor 251, and further the connector B 245, as shown in Fig. 3B. In the base 210, the vicinity of the moving magnet 233 and the vicinity of the rotor 251 of the spindle 232 are composed of a nonmagnetic material and the other portion is made of a magnetic shielding material. In addition, in the cartridge 234 which is removed from the driving device 235, the portions of the nonmagnetic material in the vicinity of the moving magnet 233 and in the vicinity of the rotor 251 of the spindle 232 of the base 210 are covered with the shutter mechanism 241 composed of a magnetic shielding material. Accordingly, there is no fear of the information written on the recording medium 222 being damaged due to external influence.Although the moving magnet 233 and the actuator driving mechanism 237 are coupled in a non-contacting state by electromagnetic induction in order to rock the actuator 225 in this embodiment, they may be coupled in a contacting state as in another embodiment shown in Figs. 6 and 7.In this embodiment, a turntable 358 composed of a magnetic material is attached to one end of a pivot 326. An elastic thin-film seal 359 which is deformable in the rotational direction of the pivot 326 so as not to obstruct the rocking movement of the pivot 326 is provided between the pivot 326 and a base 310. An actuator driving mechanism 337 is provided with a coupling member 360 composed of a magnet in such a manner as to be removably coupled with the turntable 358. The actuator driving mechanism 337 is composed of magnets 361 and a coil 362 so as to rotate the coupling member 360. In this structure, when a cartridge 334 is inserted into a driving mechanism, the coupling member 360 is magnetically coupled with the turntable 358 into one body while rotating such that the end surface of a notched portion 364 provided on the turntable 358 of an actuator 325 shown in Fig. 7 abuts against the end surface of a notched portion 363 provided on the coupling member 360. Consequently, the actuator 325 to which the driving force of the actuator driving mechanism 337 is transmitted is rocked. At this time, the elastic thin-film seal 359 repeats clockwise or counterclockwise deformation in correspondence with the rotation or reverse rotation of the turntable 358. Thus, this embodiment has similar advantages to those of the first embodiment. | A magnetic disk drive system comprising: A) a cartridge (234) including: a) a planar magnetic recording medium (222);b) a spindle (232) fixed to the central part of the magnetic recording medium (222);c) a magnetic head (223) which is fixed to an actuator (225) and which magnetically writes information on the magnetic recording medium (222) and reads the information written on the magnetic recording medium (222); andd) an actuator (225) which supports the magnetic head (223) which supports the magnetic head (223) at one and thereof and which rocks around the pivot (226) in a plane parallel to the recording surface of the recording medium (222); andB) a driving device (235) including: e) a loading mechanism (240) for mounting the cartridge (234) on the driving device (235) while opening a shutter mechanism (241) and for removing the cartridge (234) while closing the shutter mechanism (241); f) a spindle driving mechanism (236) for rotating the magnetic recording medium (222) by rotating the spindle (232) in the state in which the cartridge (234) is mounted; andg) an actuator driving mechanism (237) for moving the position of the magnetic head (223) by rocking the actuator (225) in the state in which the cartridge (234) is mounted, characterized in that the cartridge (234) has a sealed structure and that the shutter mechanism (241), when it is closed, accomodates the magnetic recording medium (222), spindle (232), magnetic head (223) and actuator (225) in the cartridge (234) in a sealed state and, when it is opened, exposes at least a part of the actuator (225) and that an elastic thin-film seal (359) which is an annular member composed of a plurality of scale-like pieces covers the peripheral edge of the exposed pivot (326), which is deformed by the rotational force around the pivot (326) and which absorbs the rotational force by the deformation and seals at least the peripheral edge of the exposed pivot (326);a turntable (358) is opposed to one end of the pivot (326) in such a manner as to seal the exposed pivot (326) in the axial direction when the cartridge (234) is mounted on the driving mechanism (235) and the shutter mechanism (241) is open; and a coupling member (360) is engaged with the turntable (358) so as to transmit the rotational force of the actuator driving mechanism (337) and rotate the turntable (358).A magnetic disk drive system according to claim 1, wherein the shutter mechanism (241) is composed of a magnetic shielding material.A magnetic disk drive system according to claim 1, wherein the surface of the cartridge (234) except the surface which faces the spindle driving mechanism (236) and the actuator driving mechanism (237, 337) is covered with a magnetic shielding material.A magnetic disk drive system according to claim 1, wherein the cartridge (234) includes further a means for covering the the surface which faces the spindle driving mechanism (236) and the actuator driving mechanism (237, 337) with a nonmagnetic material when the shutter mechanism (241) is closed.A magnetic disk drive system according to claim 1, wherein the cartridge (234) further includes a cartridge connceting mechanism (245) and the actuator (225, 335), respectivelly, from a driving circuit and transmitting and receiving an electric signal between the magnetic head (223) and the driving circuit; and the driving device (235) further includes a driving device connecting mechanism (244) which is connected to the cartridge connecting mechanism (245) and which is separated from the cartridge connecting mechanism (245) when the cartridge (234) is removed from the driving device (235).A magnetic disk drive system according to claim 1, wherein the cartridge (234) further includes: a case which is composed of a base (210) and a cover (230) and which constitutes the outer frame of the cartridge (234);a subbase (248) for fixing the spindle (232) and the pivot (226, 326) of the actuator (225, 325);a subplate (249) which is supported by the subbase (248) and which covers the magnetic recording medium (222); anda buffer material (250) with which the gap between the subbase (248) and the inner wall of the case and the gap between the subplate (249) and the inner wall of the case are filled.A magnetic disk drive system according to claim 1, wherein the cartridge (234) further includes: a suspension (224) which is a leaf spring with one end being fixed to the actuator (325) and the other end supporting the magnetic head (223) in such a manner as to enable the magnetic head (223) to be pushed up vertically relative to the actuator (325);a means for moving the magnetic head outside of the recording surface of the magnetic recording medium (222) in a plane which is parallel to the recording surface of the magnetic recording medium (222) by rotating the actuator (325) when the shutter mechanism (241) is closed>;a retracting cam (253) for pushing up the suspension (224) when the shutter (241) is closed; anda ramp loading mechanism (29) for receiving the suspension (224) and holding the vertical position of magnetic head (223) when the magnetic head (223) moves outside of the recording surface of the magnetic recording medium (222) and the suspension (224) is pushed up. | MITSUBISHI ELECTRIC CORP; MITSUBISHI DENKI KABUSHIKI KAISHA | KAMO MASAYOSHI; KAWADA JUNJI; SHOJI KENJI; KAMO, MASAYOSHI; KAWADA, JUNJI; SHOJI, KENJI; Kamo, Masayoshi, c/o Mitsubishi Denki K. K.; Kawada, Junji, c/o Mitsubishi Denki Engin. K. K.; Shoji, Kenji, c/o Mitsubishi Denki K. K. |
EP-0490077-B1 | 490,077 | EP | B1 | EN | 19,970,806 | 1,992 | 20,100,220 | new | C12N15 | A61K48, C07H21 | A61K47, C12N15, A61K38, A61K48, C07K14, A61P35, A61K31 | C12N 15/11B5, A61K 47/48H4N, M12N301:450, A61K 47/48H4, K61K38:00 | Antisense oligonucleotides for treatment of cancer | RIα antisense oligonucleotides and pharmaceutical compositions thereof are disclosed. Methods for treating certain cancers in animals comprising administering to animals an effective amount of an RIα antisense oligonucleotide, or a pharmaceutical composition thereof, are also disclosed. | FIELD OF THE INVENTIONThe invention is in the field of medicinal chemistry. In particular, the invention relates to the use of certain antisense oligonucleotides for the treatment of cancer. BACKGROUND OF THE INVENTIONControl mechanisms for cell growth and differentiation are disrupted in neoplastic cells (Potter, V.R. (1988) Adv. Oncol.4, 1-8; Strife, A. & Clarkson, B. (1988) Semin. Hematol.25, 1-19; Sachs, L. (1987) Cancer Res.47, 1981-1986). cAMP, an intracellular regulatory agent, has been considered to have a role in the control of cell proliferation and differentiation (Pastan, I., Johnson, G.S. & Anderson, W.B. (1975) Ann. Rev. Biochem.44, 491-522; Prasad, K.N. (1975) Biol. Rev.50, 129-165; Cho-Chung, Y.S. (1980) J. Cyclic Nucleotide Res.6, 163-177; Puck, T.T. (1987) Somatic Cell Mot. Genet.13, 451-457). Either inhibitory or stimulatory effects of cAMP on cell growth have been reported previously in studies in which cAMP analogs such as N6-O2'-dibutyryladenosine 3',5'-cyclic monophosphate or agents that raise intracellular cAMP to abnormal and continuously high levels were used, and available data are interpreted very differently (Chapowski, F.J., Kelly, L.A. & Butcher, R.W. (1975) Adv. Cyclic Nucleotide Protein Phosphorylat. Res.6, 245-338; Cho-Chung, Y.S. (1979) in Influence of Hormones on Tumor Development, eds. Kellen, J.A. & Hilf, R. (CRC, Boca Raton, FL), pp. 55-93); Prasad, K.N. (1981) in The Transformed Cell, eds. Cameron, L.L. & Pool, T.B. (Academic, New York), pp. 235-266; Boynton, A.L. & Whitfield, J.F. (1983) Adv. Cyclic Nucleotide Res.15, 193-294). Recently, site-selective cAMP analogs were discovered which show a preference for binding to purified preparations of type II rather than type I cAMP-dependent protein kinase in vitro (Robinson-Steiner, A.M. & Corbin, J.D. (1983) J. Biol. Chem. 258, 1032-1040; Øgreid, D., Ekanger, R., Suva, R.H., Miller, J.P., Sturm, P., Corbin, J. D. & Døskeland, S.O. (1985) Eur. J. Biochem.150, 219-227), provoke potent growth inhibition, differentiation, and reverse transformation in a broad spectrum of human and rodent cancer cell lines (Katsaros, D., Tortora, G., Tagliaferri, P., Clair, T., Ally, S., Neckers, L., Robins, R.K. & Cho-Chung, Y.S. (1987) FEBS Lett. 223, 97-103; Tortora, G., Tagliaferri, P., Clair, T., Colamonici, O., Neckers, L.M., Robins, R.K. & Cho-Chung, Y.S. (1988) Blood, 71, 230-233; Tagliaferri,, P., Katsaros, D., Clair, T., Robins,. R.K. & Cho-Chung, Y.S. (1988) J. Biol. Chem.263, 409-416). The type I and type II protein kinases are distinguished by their regulatory subunits (RI and RII, respectively) (Corbin, J.D., Keely, S.L. & Park, C.R. (1975) J. Biol. Chem.250, 218-225; Hofmann, F., Beavo, J.A. & Krebs, E.G. (1975) J. Biol. Chem.250, 7795-7801). Four different regulatory subunits [RIα (previously designated RI) (Lee, D.C., Carmichael, D.F., Krebs, E.G. & McKnight, G.S. (1983) Proc. Natl. Acad. Sci.USA80, 3608-3612), RIβ (Clegg, C.H., Cadd, G.G. & McKnight, G.S. (1988) Proc. Natl. Acad. Sci. USA85, 3703-3707), RIIα (RII54) (Scott, J.D., Glaccum, M.B., Zoller, M.J., Uhler, M.D., Hofmann, D.M., McKnight, G.S. & Krebs, E.G. (1987) Proc. Natl. Acad. Sci. USA 84, 5192-5196) and RIIβ (RII51) (Jahnsen, T., Hedin, L., Kidd, V.J., Beattie, W.G., Lohmann, S.M., Walter, U., Durica, J., Schulz, T.Z., Schlitz, E., Browner, M., Lawrence, C.B., Goldman, D., Ratoosh, S.L. & Richards, J.S. (1986) J. Biol. Chem.261, 12352-12361)] have now been identified at the gene/mRNA level. Two different catalytic subunits [Cα (Uhler, M.D., Carmichael, D.F., Lee, D.C. Chrivia, J.C., Krebs, E.G. & McKnight, G.S. (1986) Proc. Natl. Acad. Sci. USA83, 1300-1304) and Cβ (Uhler, M.D., Chrivia, J.C. & McKnight, G.S. (1986) J. Biol. Chem.261, 15360-15363; Showers, M.O. & Maurer, R.A. (1986) J. Biol. Chem. 261, 16288-16291)] have also been identified; however, preferential coexpression of either one of these catalytic subunits with either the type I or type II protein kinase regulatory subunit has not been found (Showers, M.O. & Maurer, R.A. (1986) J. Biol. Chem.261, 16288-16291). The growth inhibition by site-selective cAMP analogs parallels reduction in RIα with an increase in RIIβ, resulting in an increase of the RIIβ/RIα ratio in cancer cells (Ally, S., Tortora, G., Clair, T., Grieco, D., Merlo, G., Katsaros, D., Øgreid, D., Døskeland, S.O., Jahnsen, T. & Cho-Chung, Y.S. (1988) Proc. Natl. Acad. Sci. USA85, 6319-6322; Cho-Chung, Y.S. (1989) J. Natl. Cancer Inst.81, 982-987). Such selection modulation of Rα versus RIIβ is not mimicked by treatment with N6,O2'-dibutyryladenosine 3',5'-cyclic monophosphate, a previously studied cAMP analog (Ally, S., Tortora, G., Clair, T., Grieco, D., Merlo, G., Katsaros, D., Øgreid, D., Døskeland, S.O., Jahnsen, T. & Cho-Chung, Y.S. (1988) Proc. Nat],Acad. Sci. USA85, 6319-6322). The growth inhibition further correlates with a rapid translocation of RIIβ to the nucleus and an increase in the transcription of the RIIβ gene (Ally, S., Tortora, G., Clair, T., Grieco, D., Merlo, G., Katsaros, D., Øgreid, D., Døskeland, S.O., Jahnsen, T. & Cho-Chung, Y.S. (1988) Proc. Natl. Acad. Sci. USA85, 6319-6322). These results support the hypothesis that RIβ plays an important role in the cAMP growth regulatory function (Cho-Chung, Y.S. (1989) J. Natl. Cancer Inst.81, 982-987). Antisense RNA sequences have been described as naturally occurring biological inhibitors of gene expression in both prokaryotes (Mizuno, T., Chou, M-Y, and Inouye, M. (1984), Proc. Natl. Acad. Sci. USA81, (1966-1970)) and eukaryotes (Heywood, S.M. Nucleic Acids Res.,14, 6771-6772 (1986)), and these sequences presumably function by hybridizing to complementary mRNA sequences, resulting in hybridization arrest of translation (Paterson, B.M., Roberts, B.E., and Kuff, E.L., (1977) Proc. Natl. Acad. Sci. USA, 74, 4370-4374. Antisense oligodeoxynucleotides are short synthetic nucleotide sequences formulated to be complementary to a specific gene or RNA message. Through the binding of these oligomers to a target-DNA or mRNA sequence, transcription or translation of the gene can be selectively blocked and the disease process generated by that gene can be halted. The cytoplasmic location of mRNA provides a target considered to be readily accessible to antisense oligodeoxynucleotides entering the cell; hence much of the work in the field has focused on RNA as a target. Currently, the use of antisense oligodeoxynucleotides provides a useful tool for exploring regulation of gene expression in vitro and in tissue culture (Rothenberg, M., Johnson, G., Laughlin, C., Green, I., Craddock, J., Sarver, N., and Cohen, J.S. (1989) J. Natl. Cancer Inst., 81:1539-1544. Tortora et al, PNAS USA 87:705-708 (January 1990) discloses an RIα antisense oligodeoxynucleotide (corresponding to the antisense oligonucleotide having SEQ.ID NO: 1) which inhibits the growth and differentiation of only one cell line of leukemia in vitro. No in vivo data demonstrating that said oligonucleotide is capable of inhibiting cancerous cells in vivo is shown and no S-oligonucleotide is described. Cho-Chung et al, Proc. Am. Assoc. Cancer Res. 31:29, Abstract No. 171 (March 1990) discloses that an RIα subunit antisense oligodeoxynucleotide effects growth inhibition and change of morphology of human colon, breast, and gastric carcinoma, neuroblastoma and F9 teratocarcinoma cell lines. Tortora et al, Proc. Am. Assoc. Cancer Res. 31:38, Abstract No. 220 (March 1990), discloses that an RIα subunit antisense oligonucleotide of the cAMP-dependent protein kinase inhibits proliferation of human HL-60 promyelocytic leukemia. Clair, T. et al (March 1991), Proceedings of the American Association for Cancer Research, Vol. 32, Abstract 1645, describes the use of a 21-mer antisense R1-alpha S-oligonucleotide which inhibits the growth of LS 174T human colon carcinoma in athymic mice. SUMMARY OF THE INVENTIONThe invention is related to the discovery that inhibiting the expression of RIα in leukemia cells by contact with an antisense O-oligonucleotides and S-oligonucleotides for RIα results in the inhibition of proliferation and the stimulation of cell differentiation. Accordingly, the invention is directed to the use of RIα antisense oligonucleotides for the treatment of cancer. In particular, the invention is related to the use of antisense oligonucleotides SEQ ID NO: 2, 3 and 4 for the preparation of a medicament suitable for treating cancer, wherein said oligonucleotides are complementary to a region in the RI-alpha (SEQ ID NO: 6) and are capable of suppressing growth of cancer cells susceptible to growth suppression in animals including humans. The invention is also related to a method for treating cancer by suppressing growth of cancer cells susceptible to growth suppression and for inducing cancer cell differentiation in an animal comprising administering to an animal including human in need of such treatment a cancer cell growth suppressing amount of an RIα antisense oligonucleotide. DESCRIPTION OF THE FIGURESFig. 1 depicts a graph showing the effect of Rα antisense oligodeoxynucleotide on the basal rate of growth of HL-60 leukemic cells (A) and the growth of these cells when treated with cAMP analogs or TPA (B). A, cells were grown (see the Examples) in the absence (O) or presence (•) of RIα antisense oligodeoxynucleotide (15 µM). At indicated times, cell counts in duplicate were performed. Data represent the average values ± SD of four experiments. B, On day 4 of experiment A, cells exposed or unexposed to RIα antisense oligodeoxynucleotide were reseeded (day 0) at 5 x 105 cells/dish, and cells pre-exposed to RIα antisense oligodeoxynucleotide were further treated with the oligomer at day 0 and day 2. cAMP analogs and TPA were added one time at day 0. Cell counts were performed on a Coulter counter on day 4. 8-Cl, 8-Cl-cAMP (10 µM); 8-C1 + N6-B, 8-C1-cAMP (5 µM) + N6-benzyl-cAMP (5 µM); TPA (10-8 M). The data represent the average values ± SD of four experiments. Fig. 2 depicts a graph showing the effect of RIα antisense oligodeoxynucleotide on the morphologic transformation of HL-60 cells. Cells either exposed or unexposed to RIα antisense oligodeoxynucleotide were treated with cAMP analogs or TPA as described in Fig. 1B. On day 4 (see Fig. 1B), cells were washed twice in Dulbecco's phosphate-buffered saline and were pelleted onto a glass slide by cytocentrifuge. The resulting cytopreparations were fixed and stained by Wright's stain. x 180. Fig. 3 depicts a Northern blot showing decreased RIα mRNA expression in HL-60 leukemic cells exposed to RIα antisense oligodeoxynucleotide. Cells were either exposed or unexposed to RIα antisense oligodeoxynucleotide (15 µM) for 8 hr. Isolation of total RNA and Northern blot analysis followed the methods described in the Examples. A, ethidium bromide staining of RNA; M, markers of ribosomal RNAs; lanes 1, 2, cells unexposed or exposed to RIα antisense oligomer. B, Northern blot analysis; the same nitrocellulose filter was hybridized to both RIα and actin probes in sequential manner. Lanes 1, 2, cells unexposed or exposed to RIα antisense oligomer. Fig. 4 depicts an SDS-PAGE showing the effect of RIα antisense oligodeoxynucleotide on the basal and induced levels of RIα and RIIβ cAMP receptor proteins in HL-60 leukemic cells. Cells were either exposed to RIα antisense oligodeoxynucleotide (15 µM) or treated with cAMP analogs as described in Fig. 1. Preparation of cell extracts, the photoactivated incorporation of 8-N3-[32P]cAMP and immunoprecipitation using the anti-RIα or anti-RIIβ antiserum and protein A Sepharose, and SDS-PAGE of solubilized antigen-antibody complex followed the methods described in the Examples. Preimmune serum controls were carried out simultaneously and detected no immunoprecipitated band. M, 14C-labeled marker proteins of known molecular weight; RIα, the 48,000 molecular weight RI (Sigma); RIIα, the 56,000 molecular weight RII (Sigma). Lanes RIα and RIIβ are from photoaffinity labeling with 8-N3-[32P]cAMP only; lanes 1 to 3, photoaffinity labeling with 8-N3-[32P]cAMP followed by immunoprecipitation with anti-RIα or anti-RIIβ antiserum. 8-Cl, 8-Cl-cAMP (5 µM); N6-benzyl,N6-benzyl-cAMP (5µM). The data in the table represent quantification by densitometric scanning of the autoradiograms. The data are expressed relative to the levels in control cells unexposed to RIα antisense oligomer and untreated with cAMP analog, which are set equal to 1 arbitrary unit. The data represent an average ± SD of three experiments. A and B, immunoprecipitation with anti-RIa and anti-RIIβ antisera, respectively. Fig. 5 depicts graphs showing the growth inhibition of human cancer cell lines by RIα antisense oligodeoxynucleotide having SEQ ID No: 1 (O-oligo and S-oligo derivatives), compared to controls. Cell lines: SK-N-SH, neuroblastoma; LS-174T, colon carcinoma; MCF-7, breast carcinoma; TMK-1, gastric carcinoma. E2, estradiol-17β. Fig. 6 depicts the change in morphology of SK-N-SH human neuroblastoma cells exposed to RIα antisense oligodeoxynucleotide having SEQ ID No: 1. Fig. 7 depicts a graph showing that RIα antisense oligodeoxynucleotide and its phosphorothioate analog inhibit the in vivo growth of LS-174T human colon carcinoma in athymic mice. Figure 7A shows the oligodeoxynucleotide concentration-dependent inhibition of tumor growth. O-oligo, RIα antisense oligodeoxynucleotide; S-oligo, phosphorothioate analog of RIα antisense oligomer. The cholesterol pellets (total weight 20 mg) containing the indicated doses of O-oligo or S-oligo were implanted s.c. one time, at zero time, and tumor sizes were measured. Tumor volume (see Materials and Methods, Example 3) represents an average ± S.D. of 7 tumors. Figure 7B shows the temporal effect of antisense oligodeoxynucleotide phosphorothioate analogs on tumor growth. S-oligos as indicated at 0.3 mg dose in cholesterol pellets (total weight 20 mg) were implanted s.c. 2x/week, and tumor volume (see Materials and Methods, Example 3) represents an average ± S.D. of 7 tumors. DESCRIPTION OF THE PREFERRED EMBODIMENTSAntisense therapy is the administration of exogenous oligonucleotides which bind to a target polynucleotide located within the cells. The term antisense refers to the fact that such oligonucleotides are complementary to their intracellular targets, e.g., RIα. See for example, Jack Cohen, OLIGODEOXYNUCLEOTIDES, Antisense Inhibitors of Gene Expression, CRC Press, 1989; and Synthesis 1:1-5 (1988). The RIα antisense oligonucleotides of the present invention include derivatives such as S-oligonucleotides (phosphorothioate derivatives or S-oligos, see, Jack Cohen, supra) which exhibit enhanced cancer cell growth inhibitory action (see Figures 5 and 7A). S-oligos (nucleoside phosphorothioates) are isoelectronic analogs of an oligonucleotide (O-oligo) in which a nonbridging oxygen atom of the phosphate group is replaced by a sulfur atom. The S-oligos of the present invention may be prepared by treatment of the corresponding O-oligos with 3H-1,2-benzodithiol-3-one-1,1-dioxide which is a sulfur transfer reagent. See Iyer, R.P. et al., J. Org. Chem.55:4693-4698 (1990); and Iyer, R.P. et al., J. Am. Chem. Soc. 112:1253-1254 (1990), the disclosures of which are fully incorporated by reference herein. The RIα antisense oligonucleotides used in the present invention may be RNA or DNA which is complementary to and stably hybridizes with the first 100 N-terminal codons of the RIα genome or the corresponding mRNA. Use of an oligonucleotide complementary to this region allows for the selective hybridization to RIα mRNA and not to mRNA specifying other regulatory subunits of protein kinase. Preferably, the RIα antisense oligonucleotides of the present invention are a 15 to 30-mer fragment of the antisense DNA molecule having SEQ ID NO:5 which hybridizes to RIα mRNA. RIα antisense oligonucleotide is a 15- to 30-mer oligonucleotide which is complementary to a region in the first 100 N-terminal codons of RIα (Seq. ID No:6). The nucleotide sequence of these RIα antisense oligonucleotides is SEQ ID No:2, SEQ ID No:3, or SEQ ID No:4. Pharmaceutical compositions may comprise an effective amount of at least one of the RIα antisense oligonucleotides of the invention in combination with a pharmaceutically acceptable carrier. In one embodiment, a single RIα antisense oligonucleotide is utilized. In another embodiment, two RIα antisense oligonucleotides are utilized which are complementary to adjacent regions of the RIα genome. Administration of two RIα antisense oligonucleotides which are complementary to adjacent regions of the RIα genome or corresponding mRNA may allow for more efficient inhibition of RIα genomic transcription or mRNA translation, resulting in more effective inhibition of cancer cell growth. Preferably, the RIα antisense oligonucleotide is coadministered with an agent which enhances the uptake of the antisense molecule by the cells. For example, the RIα antisense oligonucleotide may be combined with a lipophilic cationic compound which may be in the form of liposomes. The use of liposomes to introduce nucleotides into cells is taught, for example, in U.S. Patent Nos. 4,897,355 and 4,394,448, the disclosures of which are incorporated by reference in their entirety. See also U.S. Patent Nos. 4,235,871, 4,231,877, 4,224,179, 4,753,788, 4,673,567, 4,247,411, 4,814,270 for general methods of preparing liposomes comprising biological materials. Alternatively, the RIα antisense oligonucleotide may be combined with a lipophilic carrier such as any one of a number of sterols including cholesterol, cholate and deoxycholic acid. A preferred sterol is cholesterol. In addition, the RIα antisense oligonucleotide may be conjugated to a peptide that is ingested by cells. Examples of useful peptides include peptide hormones, antigens or antibodies, and peptide toxins. By choosing a peptide that is selectively taken up by the neoplastic cells, specific delivery of the antisense agent may be effected. The RIα antisense oligonucleotide may be covalently bound via the 5'OH group by formation of an activated aminoalkyl derivative. The peptide of choice may then be covalently attached to the activated RIα antisense oligonucleotide via an amino and sulfhydryl reactive hetero bifunctional reagent. The latter is bound to a cysteine residue present in the peptide. Upon exposure of cells to the RIα antisense oligonucleotide bound to the peptide, the peptidyl antisense agent is endocytosed and the RIα antisense oligonucleotide binds to the target RIα mRNA to inhibit translation. See PCT Application Publication No. PCT/US89/02363. As antineoplastic agents, the RIα antisense oligonucleotides of the present invention are useful in treating a variety of cancers, including, but not limited to, gastric, pancreatic, lung, breast, anal, colorectal, head and neck neoplasms, neuroblastomas, melanoma and various leukemias. The RIα antisense oligonucleotides used in the invention may also be active against the following tumor systems: F9 teratocarcinoma, SK-N-SH neuroblastoma, TMK-1 gastric carcinoma, HL-60 promyelocytic Leukemia, Leukemia L-1210, Leukemia P388, P1534 leukemia, Friend Virus-Leukemia, Leukemia L4946, Mecca lymphosarcoma, Gardner lymphosarcoma, Ridgway Osteogenic sarcoma, Sarcoma 180 (ascites), Wagner osteogenic sarcoma, Sarcoma T241, Lewis lung carcinoma, Carcinoma 755, CD8F, MCF-7 breast carcinoma, Colon 38, LS-174T colon carcinoma, Carcinoma 1025, Ehrlich carcinoma (ascites & solid), Krubs 2 carcinoma (ascites), Bashford carcinoma 63, Adenocarcinoma E 0771, B16 Melanoma, Hardin-Passey melanoma, Giloma 26, Miyona adenocarcinoma, Walker carcinosarcoma 256, Flexner-Jobling carcinoma, Jensen sarcoma, Iglesias Sarcoma, Iglesias ovarian tumor, Murphy-Sturn lymphosarcoma, Yoshida sarcoma, Dunning leukemia, Rous chicken sarcoma, and Crabb hamster sarcoma. The RIα antisense oligonucleotides and the pharmaceutical compositions used in the present invention may be administered by any means that achieve their intended purpose. For example, administration may be by parenteral, subcutaneous, intravenous, intramuscular, intra-peritoneal, or transdermal routes. The dosage administered will be dependent upon the age, health, and weight of the recipient, kind of concurrent treatment, if any, frequency of treatment, and the nature of the effect desired. Compositions used in this invention include all compositions wherein the RIα antisense oligonucleotide is contained in an amount which is effective to achieve inhibition of proliferation and/or stimulate differentiation of the subject cancer cells. While individual needs vary, determination of optimal ranges of effective amounts of each component is with the skill of the art. Typically, the RIα antisense oligonucleotide may be administered to mammals, e.g. humans, at a dose of 0.005 to 1 mg/kg/day, or an equivalent amount of the pharmaceutically acceptable salt thereof, per day of the body weight of the mammal being treated. In addition to administering the RIα antisense oligonucleotides as a raw chemical in solution, the RIα antisense oligonucleotides may be administered as part of a pharmaceutical preparation containing suitable pharmaceutically acceptable carriers comprising excipients and auxiliaries which facilitate processing of the RIα antisense oligonucleotide into preparations which can be used pharmaceutically. Suitable formulations for parenteral administration include aqueous solutions of the RIα antisense oligonucleotides in water-soluble form, for example, water-soluble salts. In addition, suspensions of the active compounds as appropriate oily injection suspensions may be administered. Suitable lipophilic solvents or vehicles include fatty oils, for example, sesame oil, or synthetic fatty acid esters, for example, ethyl oleate or triglycerides. Aqueous injection suspensions may contain substances which increase the viscosity of the suspension include, for example, sodium carboxymethyl cellulose, sorbitol, and/or dextran. Optionally, the suspension may also contain stabilizers. The antisense oligonucleotides used in the present invention may be prepared according to any of the methods that are well known to those of ordinary skill in the art. Preferably, the antisense oligonucleotides are prepared by solid phase synthesis. See, Goodchild, J., Bioconjugate Chemistry,1:165-167 (1990), for a review of the chemical synthesis of oligonucleotides. Alternatively, the antisense oligonucleotides can be obtained from a number of companies which specialize in the custom synthesis of oligonucleotides. Having now generally described this invention, the same will be understood by reference to an example which is provided herein for purposes of illustration only and is not intending to be limited unless otherwise specified. The entire text of all applications, patents and publications, if any, cited above and below are hereby incorporated by reference. EXAMPLESExample 1Oligodeoxynucleotides. The 21-mer oligodeoxynucleotides used in the present studies were synthesized at Midland Certified Reagent Co. (Midland, TX) and had the following sequences: human RIα (Sandberg, M., Tasken, K., Oyen, O., Hansson, V. & Jahnsen, T. (1987) Biochem. Biophys. Res. Commun.149, 939-945) antisense, 5'-GGC-GGT-ACT-GCC-AGA-CTC-CAT-3' (SEQ ID No:1); human RIIβ (Levy, F.O., Oyen, O., Sandberg, M., Tasken, K., Eskild, W., Hansson, V. & Jahnsen, T. (1988) Mol. Endocrinol., 2, 1364-1373) antisense 5'-CGC-CGG-GAT-CTC-GAT-GCT-CAT-3'; human RIIα (Oyen, O., Myklebust, F., Scott, J. D., Hansson, V. & Jahnsen, T. (1989) FEBS Lett.246, 57-64) antisense, 5'-CGG-GAT-CTG-GAT-GTG-GCT-CAT-3'; and the random sequence oligodeoxynucleotide was made of a mixture of all four nucleotides at every position. Cell Growth Experiment. Cells grown in suspension culture in RPM1 1640 medium supplemented with 10% heat-inactivated fetal bovine serum, penicillin (50 U/ml), streptomycin (500 µg/ml), and 1 mM glutamine (Gibco, Grand Island, NY) were seeded at 5 x 105 cells per dish. Oligodeoxynucleotides were added after seeding and every 48 hr thereafter. Cell counts were performed on a Coulter counter. Cells unexposed or exposed to oligodeoxynucleotides for 4 days were reseeded (day 0) at 5 x 105 cells/dish, and cells pre-exposed to the oligodeoxynucleotide were further treated with the oligomer at day 0 and day 2. cAMP analogs (kindly provided by Dr. R.K. Robins, Nucleic Acid Research Institute, Costa Mesa, CA) or 12-O-tetradecanoylphorbol-13-acetate (TPA) were added one time at day 0. Cell counts were performed on day 4. Immunoprecipitation of RIα and RIIβ cAMP Receptor Proteins after Photoaffinity Labeling with 8-N3-[32P]cAMP. Cell extracts were prepared at 0-4°C. The cell pellets (2 x 106 cells), after two washes with PBS, were suspended in 0.5 ml buffer Ten (0.1 M NaC1, 5 mM MgC12, 1% Nonidet P-40, 0.5% Na deoxycholate, 2 KIU/ml bovine aprotinin, and 20 mM Tris-HCl, pH 7.4) containing proteolysis inhibitors (Tortora, G., Clair, T. & Cho-Chung, Y. S. (1990) Proc. Natl. Acad. Sci. USA87, 705-708), vortex-mixed, passed through a 22-gauge needle 10 times, allowed to stand for 30 min at 4°C, and centrifuged at 750 x g for 20 min; the resulting supernatants were used as cell lysates. The photoactivated incorporation of 8-N3-[32P]cAMP (60.0 Ci/mmol), and the immunoprecipitation using the anti-RIα or anti-RIIβ antiserum (kindly provided by Dr. S.O. Døskeland, University of Bergen, Bergen, Norway) and protein A Sepharose and SDS-PAGE of solubilized antigen-antibody complex followed the method previously described (Tortora, G., Clair, T. & Cho-Chung, Y. S. (1990) Proc. Natl. Acad. Sci. USA87, 705-708; Ekanger, R., Sand, T. E., Ogreid, D., Christoffersen, T. & Døskeland, S.O. (1985) J. Biol. Chem.260, 3393-3401). cAMP-Dependent Protein Kinase Assays. After two washes with Dulbecco's phosphate-buffered saline, cell pellets (2 x 106 cells) were lysed in 0.5 ml of 20 mM Tris (pH 7.5), 0.1 mM sodium EDTA, 1 mM dithiothreitol, 0.1 mM pepstatin, 0.1 mM antipain, 0.1 mM chymostatin, 0.2 mM leupeptin, 0.4 mg/ml aprotinin, and 0.5 mg/ml soybean trypsin inhibitor, using 100 strokes of a Dounce homogenizer. After centrifugation (Eppendorf 5412) for 5 min, the supernatants were adjusted to 0.7 mg protein/ml and assayed (Uhler, M. D. & McKnight, G. S. (1987) J. Biol. Chem.262, 15202-15207) immediately. Assays (40 µl total volume) were performed for 10 min at 30°C and contained 200 µM ATP, 2.7 x 106 cpm γ[32P)ATP, 20 mM MgC12, 100 µM Kemptide (Sigma K-1127) (Kemp, B. E., Graves, D. J., Benjamin, E. & Krebs, E. G. (1977) J. Biol. Chem.252, 4888-4894), 40 mM. Tris (pH 7.5), ± 100 µM protein kinase inhibitor (Sigma P-3294) (Cheng, H.-C., Van Patten, S. M., Smith, A. J. & Walsh, D. A. (1985) Biochem. J. 231, 655-661), ± 8 µM cAMP and 7 µg of cell extract. The phosphorylation of Kemptide was determined by spotting 20 µl of incubation mixture on phosphocellulose filters (Whatman, P81) and washing in phosphoric acid as described (Roskoski, R. (1983) Methods Enzymol.99, 3-6). Radioactivity was measured by liquid scintillation using Econofluor-2 (NEN Research Products NEF-969). Isolation of Total RNA and Northern Blot Analysis. The cells (108 washed twice with phosphate-buffered saline) were lysed in 4.2 M guanidine isothiocyanate containing 25 mM sodium citrate (pH 7.0), 0.5% sarcosyl (N-lauroylsarcosine Na+), and 0.1 M β-mercaptoethanol, and the lysates were homogenized, and total cellular RNA was sedimented through a CsCl cushion (5.7 M CsCl, 10 mM EDTA) as described by Chirgwin et al. (Chirgwin, J. M., Przybyla, A. E., MacDonald, R. Y. & Rutter, W. J. (1977) Biochemistry18, 5284-5288). Total cellular RNA containing 20 mM 3-[N-morpholine]propane-sulfonic acid (pH 7.0), 50% formamide, and 6% formaldehyde was denatured at 65°C for 10 min and electrophoresed through a denaturing 1.2% agarose-2.2 M formaldehyde gel. The gels were then transferred to Biotrans nylon membranes (ICN Biomedicals) by the method of Thomas (Thomas, P. S. (1980) Proc. Natl. Acad. Sci. USA77, 5201-5205) and hybridized to the following two 32P-labeled nick-translated cDNA probes: 1.5 kilobase (kb) cDNA clone containing the entire coding region for the human cAMP-dependent protein kinase type I regulatory subunit, RIα (Sandberg, M., Tasken, K., Oyen, Q., Hansson, V. & Jahnsen, T. (1987) Biochem. Biophys. Res. Commun.149, 939-945) (kindly provided by Dr. T. Jahnsen, Institute of Pathology, Rikshospitalet, Oslo, Norway), and human β actin (Oncor p7000 β actin). RESULTSThe RIα antisense oligodeoxynucleotide at 15 µM concentration had immediate effects on the rate of proliferation of HL-60 cells. By 4-5 days in culture, while cells unexposed to RIα antisense oligomer demonstrated an exponential rate of growth, cells exposed to the antisense oligomer exhibited a reduced growth rate and eventually stopped replicating (Fig. 1A). This inhibitory effect on cell proliferation persisted throughout the culture period. The growth inhibition was not due to cell killing; cells were over 90% viable after exposure to RIα antisense oligomer (15 µM) for 7 days as assessed by flow cytometry using forward and side scatter. RIα sense, RIIα, or RIIβ antisense, or a random sequence oligodeoxynucleotide had-no such growth inhibitory effect. Cells unexposed or exposed to RIα antisense oligodeoxynucleotide for 4 days in culture were reseeded and examined for their response to treatment with cAMP analogs or TPA. In cells unexposed to RIα antisense oligodeoxynucleotide, 8-C1-cAMP (10 µM) produced 60% growth inhibition, and 80% growth inhibition was achieved by 8-Cl-cAMP (5 µM) plus N6-benzyl-cAMP (5 µM) (Fig. 1B) (Tortora, G., Tagliaferri, P., Clair, T., Colamonici, O. Neckers, L. M., Robins, R. K. & Cho-Chung, Y. S. (1988) Blood71, 230-233), and TPA (10-8 M) exhibited 60% growth inhibition (Fig. 1B). In contrast, cells exposed to antisense oligodeoxynucleotide exhibited retarded growth (25% the rate of growth of cells unexposed to the antisense oligomer) and neither cAMP analogs nor TPA brought about further retardation of growth (Fig. 1B). HL-60 cells undergo a monocytic differentiation upon treatment with site-selective cAMP analogs. Cells either unexposed or exposed to Rα antisense oligodeoxynucleotide were examined for their morphology before and alter treatment with cAMP analogs. As shown in Fig. 2, in cells unexposed to RIα antisense oligomer, 8-Cl-cAMP plus N6-benzyl-cAMP induced a monocytic morphologic change characterized by a decrease in nuclear-to-cytoplasm ratio, abundant ruffled and vacuolated cytoplasm, and loss of nucleoli. Strikingly, the same morphologic change was induced when cells were exposed to RIα antisense oligodeoxynucleotide (Fig. 2). Moreover, the morphologic changes induced by antisense oligomer were indistinguishable from that induced by TPA (Fig. 2). To provide more evidence that the growth inhibition and monocytic differentiation induced in HL-60 cells exposed to the RIα antisense oligodeoxynucleotide were due to an intracellular effect of the oligomer, the RIα mRNA level was determined. As shown in Fig. 3, 3.0 kb RIα mRNA (Sandberg, M., Tasken, K., Oyen, O., Hansson, V. & Jahnsen, T. (1987) Biochem. Biophys. Res. Commun.149, 939-945) was virtually undetectable in cells exposed for 8 hr to RIα antisense oligodeoxynucleotide (Fig. 3B, lane 2), and the decrease in RIα mRNA was not due to a lower amount of total RNA as shown by the ethidium bromide staining (compare lane 2 with lane 1 of Fig. 3A). Conversely, an enhanced level of actin mRNA was detected in cells exposed to RIα antisense oligomer (Fig. 3B). Whether the increase in actin mRNA level represents changes in cytoskeletal structure is not known. The levels of cAMP receptor proteins in these cells was then determined by immunoprecipitation using anti-RIα and anti-RIIβ antisera (Tortora, G., Clair, T. & Cho-Chung, Y. S. (1990) Proc. Natl. Acad. Sci. USA87, 705-708; Ekanger, R., Sand, T. E., Ogreid, D., Christoffersen, T. & Døskeland, S.O. (1985) J. Biol. Chem.260, 3393-3401) after photoaffinity labeling of these receptor proteins with 8-N3-[32P]cAMP. In control cells, treatment with 8-Cl-cAMP plus N6-benzyl-cAMP brought about a 70% reduction in RIα with a 3-fold increase in RIIβ, resulting in a 10-fold increase in the ratio of RIIβ/RIα (Fig. 4) (Cho-Chung, Y. S. (1989) J. Natl. Cancer Inst.81, 982-987). Exposure of these cells to RIα antisense oligodeoxynucleotide for 4 days brought about marked changes in both and RIα and RIIβ levels; an 80% reduction in RIα with a 5-fold increase in RIIβ resulted in a 25-fold increase in the ratio of RIIβ/RIα compared with that in control cells (Fig. 4). Since growth inhibition and differentiation were appreciable after 3-4 days of exposure to RIα antisense oligomer, the changing levels of RIα and RIIβ proteins appears to be an early event necessary for commitment to differentiation. Data in Fig. 4 showed that suppression of RIα by the antisense oligodeoxynucleotide brought about a compensatory increase in RIIβ level. Such coordinated expression of RI and RII without changes in the amount of C subunit has been shown previously (Hofman, F., Bechtel, P. J. & Krebs, E. G. (1977) J. Biol. Chem. 252, 1441-1447; Otten, A. D. & Mcknight, G. S. (1989) J. Biol. Chem.264, 20255-20260). The increase in RIIβ may be responsible for the differentiation induced in these cells after exposure to RIα antisense oligodeoxynucleotide. The increase in RIIβ mRNA or RIIβ protein level has been correlated with cAMP analog-induced differentiation in K-562 chronic myelocytic leukemic cells (Tortora, G., Clair, T., Katsaros, D., Ally, S., Colamonici, O., Neckers, L. M., Tagliaferri, P., Jahnsen, T., Robins, R. K. & Cho-Chung, Y. S. (1989) Proc. Natl. Acad. Sci. USA86, 2849-2852) and in erythroid differentiation of Friend erythrocytic leukemic cells (Schwartz, D. A. & Rubin, C. S. (1985) J. Biol. Chem.260, 6296-6303). In a recent report (Tortora, G., Clair, T. & Cho-Chung, Y. S. (1990) Proc. Natl. Acad. Sci. USA87, 705-708), we have provided direct evidence that RIIβ is essential for the cAMP-induced differentiation in HL-60 cells. HL-60 cells that were exposed to RIIβ antisense oligodeoxynucleotide became refractory to treatment with cAMP analogs and continued to grow. The essential role of RIIβ in differentiation of HL-60 cells was further demonstrated when these cells were exposed to both RIα and RIβ antisense oligodeoxynucleotides simultaneously. As shown in Table 1, RIα antisense oligodeoxynucleotide induced a marked increase in the expression of monocytic surface antigens [Leu15 (Landay, A., Gartland, L. & Clement, L. T. (1983) J. Immunol.131, 2757-2761) and Leu M3 (Dimitriu-Bona, A., Burmester, G. R., Waters, S. J. & Winchester, R. J. (1983) J. Immunol.130, 145-152)] along with a decrease in markers related to the immature myelogenous cells [My9 (Talle, M. A., Rao, P. E., Westberg, E., Allegar, N., Makowski, M., Mittler, R. S. & Goldstein, G. (1983) Cell. Immunol.78, 83.; Todd, R. F. III, Griffin, J. D., Ritz, J., Nadler, L. M. Abrams, T. & Schlossman, S. F. (1981) Leuk. Res.5, 491)]. These changes in surface marker expression were abolished when cells were exposed simultaneously to both and RIα and RIIβ antisense oligodeoxynucleotides- (Table 1). RIIα cAMP receptor was not detected in HL-60 cells (Cho-Chung, Y. S., Clair, T., Tagliaferri, P., Ally, S., Katsaros, D., Tortora, G., Neckers, L., Avery, T. L., Crabtree, G. W. & Robins, R. K. (1989) Cancer Invest.7(2), 161-177), and RIIα antisense oligodeoxynucleotide showed no interference with the effects of RIα antisense oligomer (Table 1). Cells exposed to both RIα and RIIβ antisense oligodeoxynucleotides were neither growth inhibited nor differentiated regardless of cAMP analog treatment. We interpret these results to reflect the blockage of cAMP-dependent growth regulatory pathway. Cells under these conditions are no longer cAMP-dependent but survive and proliferate probably through an alternate pathway. Thus, suppression of both RIα and RIIβ gene expression led to an abnormal cellular growth regulation similar to that in mutant cell lines (Gottesman, M. M. (1980) Cell22, 329-330), those that contain either deficient or defective regulatory subunits of cAMP-dependent protein kinase and are no longer sensitive to cAMP stimulus. Our results demonstrated that cAMP transduces signals for dual controls, either positive or negative, on cell proliferation, depending on the availability of RIα or RIIβ receptor proteins. The RIα antisense oligodeoxynucleotide which brought about suppression of RIα along with enhancement of RIIβ expression led to terminal differentiation of HL-60 leukemia with no sign of cytotoxicity. It is unlikely that free C subunit increase in cells exposed to RIα antisense oligodeoxynucleotide was responsible for the differentiation, because cells exposed to RIIβ antisense or both RIα and RIIβ antisense oligodeoxynucleotides, conditions which also would produce free C subunit, continued to grow and became refractory to cAMP stimulus. In order to directly verify this we measured phosphotransferase activity in cells that are exposed or unexposed to the antisense oligodeoxynucleotides using kemptide (Kemp, B. E., Graves, D. J., Benjamin, E. & Krebs, E. G. (1977) J. Biol. Chem.252, 4888-4894) as a substrate in the presence and absence of a saturating concentration of cAMP and in the presence and absence of the heat-stable protein kinase inhibitor (Cheng, H.-C., Van Patten, S. M., Smith, A. J. & Walsh, D. A. (1985) Biochem. J.231, 655-661). This method of assay gives accurate determination of the relative levels of dissociated C and total C activity. Cell extracts from untreated HL-60 cells exhibited a very low level of dissociated C and were stimulated 36-fold by cAMP (Table 2). This cAMP-stimulated activity was almost completely inhibited by the heat-stable protein kinase inhibitor (Table 2), indicating that the total C activity measured was cAMP-dependent protein kinase. In cells exposed to RIα antisense, RIIβ antisense, or RIα and RIIβ antisense oligodeoxynucleotide, the free C activity was not increased as compared to unexposed control cells, although there was a small difference in the total cAMP-stimulated activity (Table 2). These results provide direct evidence that free catalytic subunit is not responsible for the differentiation observed in HL-60 cells. Over expression of RIα cAMP receptor protein has also been found in the majority of human breast and colon primary carcinomas examined (Bradbury, A. W., Miller, W. R., Clair, T., Yokozaki, H. & Cho-Chung, Y. S. (1990) Proc. Am. Assoc. Cancer Res. 31, 172), suggesting an important in vivo role of cAMP receptor in tumor growth as well. However, the precise role of RIα in cell proliferation is not known at present. RIα may suppress RIIβ production by titrating out C subunit, or it may be a transducer of mitogenic signals leading to cell proliferation. Our results demonstrate that RIα antisense oligodeoxynucleotide provides a useful genetic tool for studies on the role of cAMP receptor proteins in cell proliferation and differentiation, and contribute to a new approach in the control of malignancy. Modulation of differentiation markers in HL-60 cells by RIα antisense oligodeoxynucleotide Treatment Surface Makers Leu15 LeuM3 My9 Control102100 RIα antisense809880 RIα antisense + RIIβ antisense112100 RIIβ antisense133100 RIα antisense + RIIα antisense8510080 Surface antigen analysis was performed by flow cytometry using monoclonal antibodies reactive with either monocytic or myeloid cells. The monoclonal antibodies used were Leu 15, Leu M3, and My9. 2 x 104 cells were analyzed for each sample, and cell gating was performed using forward and side scatter. The numbers represent % positive and represent the average values of'three experiments. Protein kinase activity in HL-60 cells Treatment Activity-cAMP Relative to control Activity+cAMP Relative to control Stimulation (fold) - PKI Control23.0 ± 6.61.0837 ± 871.036 RIα antisense22.9 ± 5.41.0944 ± 181.141 RIIβ antisense22.8 ± 8.11.01,028 ± 1541.245 RIα and RIIβ antisense24.3 ± 7.01.1802 ± 361.033 + PKI Control17.5 ± 8.71.037.0 ± 8.41.02.1 RIα antisense25.0 ± 8.81.422.6 ± 8.80.60.9 RIIβ antisense24.0 ± 2.61.424.8 ± 3.90.71.0 RIα and RIIβ antisense19.0 ± 5.91.119.1 ± 8.20.51.0 Cells were exposed to each of 15 µM concentrations of RIα, RIIβ , or RIα and RIIβ antisense oligodeoxynucleotide for 4 days as shown in Fig. 1A. The data represent an average ± SD of duplicate determinations of three identical experiments. *Picomoles phosphate transferred to Kemptide per min/mg protein. Example 2Next, the effect of O-oligo and S-oligo RIα antisense oligonucleotides on the growth of LS-174T human colon carcinoma in athymic mice was compared. Materials and Methods. We synthesized [Milligen Biosearch 8700 DNA synthesizer (Bedford, MA)] the 21-mer antisense oligodeoxynucleotides and their phosphorothioate analogs complementary to the human RIα, human RIIβ mRNA transcripts starting from the first codon, and mismatched sequence (random) oligomers of identical size. The oligomers had the following sequences: RIα antisense, 5'-GGC-GGT-ACT-GCC-AGA-CTC-CAT-3'; RIIβ antisense, 5'-CGC-CGG-GAT-CTC-GAT-GOT-CAT-3'; and random oligo, 5'-CGA-TCG-ATC-GAT-CGA-TCG-TAC-3'. LS-174T human colon carcinoma cells (2 x 106) were injected s.c. in athymic mice, and the antisense oligodeoxynucleotides in the form of either a cholesterol pellet or 50% sesame oil emulsion were administered s.c. 1 week later when mean tumor sizes usually were 25-50 mg. Tumor volume was based on length and width measurements and calculated by the formula 4/3 πr3, where r = (length + width)/4. Results and Discussion. Fig. 7 shows the dose-and time-dependent effect of an RIα antisense oligodeoxynucleotide (O-oligo) at 0.2 and 0.5 mg doses in cholesterol pellets administered s.c. one time (at zero time); it brought about 20 and 46% growth inhibition, respectively, in 7 days-when compared with control (untreated) tumors (Fig. 7A). Strikingly, the RIα antisense phosphorothioate analog (S-oligo) at a 0.2 mg dose (cholesterol pellet, s.c.) gave a 60% growth inhibition at day 7, exhibiting a 3-fold greater potency than the O-oligo antisense (Fig. 7A). The growth inhibitory effect of RIα antisense S-oligo was even greater when animals were treated for a longer period. The RIα antisense S-oligo at a 0.3 mg dose in a cholesterol pellet, 2 times/week s.c. implantation for 3 weeks, resulted in a 80% growth inhibition; the tumor growth almost stopped after 2 weeks of treatment (Fig. 7B). RIα antisense O-oligo or S-oligo administered s.c. as 50% sesame oil emulsion gave similar results. RIα antisense S-oligo brought about no apparent toxicity in animals; no body weight loss or other toxic symptoms were observed during the 3 weeks of treatment. The growth inhibitory effect brought about by RIα antisense S-oligo was the specific effect of the oligomer: RIIβ antisense or random (mismatched sequence) S-oligos of the identical size as the RIα antisense oligomer had no effect on the tumor growth (Fig. 7B). To provide more evidence that the growth inhibition observed in colon carcinomas in athymic mice treated with RIα antisense oligodeoxynucleotide was due to an intracellular effect of the oligomer, the levels of RIα and RIIβ cAMP receptor proteins in these tumors were determined. RIα levels were determined by immunoblotting (Ally, S., Proc. Natl. Acad. Sci. USA85:6319-6322 (1988)) using monoclonal antibody against human RIα (kindly provided by Drs. T. Lea, University of Oslo, Oslo, Norway, and S.O. Døskeland, University of Bergen, Bergen, Norway), and RIIβ was measured by immunoprecipitation (Tortora, G., et al., Proc. Natl. Acad. Sci. USA87:705-708 (1990)) with anti-RIIβ antiserum (kindly provided by Dr. S.O. Døskeland) after photoaffinity labeling of RIIβ with [32P], 8-N3-cAMP. As shown in Table 4, RIα antisense S-oligomer treatment brought about a marked reduction (80% decrease) of RIα level in tumors as compared with that in untreated control tumors. This suppression of RIα expression by Rα antisense S-oligomer brought about a 2-fold increase in RIIβ level (Table 4). Such coordinated expression of RIα and RIIβ without changes in the amount of catalytic subunit of protein kinase has been shown in HL-60 leukemia cells that demonstrated growth inhibition and differentiation upon exposure to RIα antisense oligodeoxynucleotide. On the other hand, a 50% increase in RIα level along with 80% suppression in RIIβ level was observed in tumors after treatment with RIIβ antisense S-oligomer (Table 4) which had no effect on tumor growth (Fig. 7). Random (mismatched sequence) S-oligomer which had no effect on tumor growth (Fig. 7) also showed no effect on RIα levels (Table 4). Thus, reduction in RIα expression appears to trigger a decrease or halt in tumor growth upon treatment with RIα antisense oligomer. Our results demonstrated that cAMP transduces signals for dual control, either positive or negative, on cell proliferation, depending on the availability of RIα or RIIβ receptor proteins. The Rα antisense oligodeoxynucleotide, which suppressed RIα and enhanced RIIβ expression, led to inhibition of in vivo growth of solid colon carcinoma in athymic mice with no symptoms of toxicity in animals. The phosphorothioate analog (S-oligo) of RIα antisense oligomer exhibited a greater potency than the antisense of unmodified oligodeoxynucleotide (O-oligo). It has been shown that S-oligos, as compared with O-oligos, more readily enter cells, are more resistant to endonucleases, and yet exhibit high efficacy in hybridization with target mRNAs or DNAs (Stein, C.A., et al., In: J.S. Cohen (ed.), Oligodeoxynucleotides: Antisense Inhibitors of GeneExpression, pp. 97-117. Boca Raton, FL, CRC Press, Inc. (1989)). These results demonstrate here for the first time the striking in vivo effect of antisense oligodeoxynucleotide in the suppression of malignancy. The depletion of RIα, the type I regulatory subunit of cAMP-dependent protein kinase, by means of an antisense oligodeoxynucleotide, especially with its phosphorothioate analog, leads to a successful halt of tumor growth in vivo with no symptoms of toxicity, suggesting great potential of this antisense oligodeoxynucleotide for clinical application. Suppression of RIα cAMP Receptor Expression by RIα Antisense Oligodeoxynucleotide (S-oligo) Results in Compensatory Increase in RIIα Receptor Treatment RIαRelative Levels RIIβNone1.0 ± 0.11.0 ± 0.1 RIα antisense S-oligo0.2 ± 0.032.0 ± 0.2 RIIβ antisense S-oligo1.5 ± 0.20.2 ± 0.02 Random S-oligo1.0 ± 0.11.0 ± 0.1 Treatment with S-oligos as indicated were the same as that in Fig. 7B. At the end of the experiment (3 weeks), tumor extracts were prepared as previously described (Ally, S. et al., Cancer Res.49:5650-5655 (1980)) and immunoblotting and immunoprecipitation of RIα and RIIβ, respectively, were performed as previously described by Ally, S., et al., Proc. Natl. Acad. Sci. USA85:6319-6322 (1988) and Tortora, G., et al., Proc. Natl. Acad. Sci. USA87:705-708 (1990). Data are from quantification by densitometric scanning of autoradiograms. Data are expressed relative to levels in control tumors (no treatment), which are set to equal to one as an arbitrary unit. Data represent an average ± S.D. of 7 tumors. In the following sequence listing, Seq ID No: 1 represents an antisense sequence corresponding to the first 7 N-terminal codons for RIα. Seq ID No: 2 represents an antisense sequence corresponding to the 8th-13th codon for RIα. Seq ID No: 3 represents an antisense sequence corresponding to the 14th-20th codon for RIα. Seq ID No: 4 represents an antisense sequence corresponding to the 94th-100th codon for RIα . Seq ID No: 5 represents an antisense sequence corresponding to the 1st-100th codon for Rα. Seq ID No: 6 represents the sense sequence corresponding to the 1st-100th codon for RIα. SEQUENCE LISTINGINFORMATION FOR SEQUENCE ID NO:1: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 21 bases (B) TYPE: Nucleic acid (C) STRANDEDNESS: Single (D) TOPOLOGY: Linear. (ii) MOLECULE TYPE: DNA (iv) ANTISENSE: yes (xi) SEQUENCE DESCRIPTION: SEQ ID NO:1: INFORMATION FOR SEQUENCE ID NO:2: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 18 bases (B) TYPE: Nucleic acid (C) STRANDEDNESS: Single (D) TOPOLOGY: linear (ii) Molecular TYPE: DNA (iv) ANTISENSE: yes (xi) SEQUENCE DESCRIPTION: SEQ ID NO:2: INFORMATION FOR SEQUENCE ID NO:3: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 21 bases (B) TYPE: Nucleic acid (C) STRANDEDNESS: Single (D) TOPOLOGY: linear (ii) MOLECULAR TYPE: DNA (iv) ANTISENSE: yes (xi) SEQUENCE DESCRIPTION: SEQ ID NO:3: INFORMATION FOR SEQUENCE ID NO:4: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 21 bases (B) TYPE: Nucleic acid (C) STRANDEDNESS: Single (D) TOPOLOGY: linear (ii) MOLECULAR TYPE: DNA (iv) ANTISENSE: yes (xi) SEQUENCE DESCRIPTION: SEQ ID NO:4: INFORMATION FOR SEQUENCE ID NO:5: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 300 bases (B) TYPE: Nucleic acid (C) STRANDEDNESS: Single (D) TOPOLOGY: linear (ii) MOLECULAR TYPE: DNA (iv) ANTISENSE: yes (xi) SEQUENCE DESCRIPTION: SEQ ID NO:5: INFORMATION FOR SEQUENCE ID NO:6: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 300 bases (B) TYPE: Nucleic acid (C) STRANDEDNESS: Single (D) TOPOLOGY: linear (ii) MOLECULAR TYPE: DNA (iv) ANTISENSE: yes (xi) SEQUENCE DESCRIPTION: SEQ ID NO:6: INFORMATION FOR SEQUENCE ID NO:7: (i) SEQUENCE CHARACTERISTICS: (A) LENGTH: 21 bases (B) TYPE: Nucleic acid (C) STRANDEDNESS: Single (D) TOPOLOGY: linear (ii) MOLECULAR TYPE: DNA (iv) ANTISENSE: yes (xi) SEQUENCE DESCRIPTION: SEQ ID NO:7: | The use of antisense oligonucleotides SEQ ID NO:2, 3 and 4 for the preparation of a medicament suitable for treating cancer, wherein said oligonucleotides are complementary to a region of RI-alpha (SEQ ID NO: 6) and are capable of suppressing growth of cancer cells susceptible to growth suppression in animals including humans. The use of claim 1, wherein said antisense oligonucleotide is DNA. The use of claim 1 or 2, wherein said antisense oligonucleotide is a fragment of antisense DNA. The use of any one of claims 1-3 wherein said cancer is selected from the group consisting of melanoma, sarcoma and carcinoma. The use of claim 4, wherein said solid cancer is colon cancer. The use of any one of claims 1-5, wherein said antisense oligonucleotide is administered as part of a pharmaceutical composition comprising a pharmaceutically acceptable carrier. The use of any one of claims 1-6, wherein said antisense oligonucleotide is an 0-oligonucleotide. The use of any one of claims 1-6, wherein said antisense oligonucleotide is an S-oligonucleotide. | YOON S CHO CHUNG; YOON, S. CHO-CHUNG | YOON S CHO-CHUNG; YOON, S. CHO-CHUNG |
EP-0490078-B1 | 490,078 | EP | B1 | EN | 19,950,809 | 1,992 | 20,100,220 | new | H01R13 | null | H01R13, H01R9 | H01R 13/658 | Shielded electrical connector | A shielded electrical connector assembly which includes an insulating housing (12a, 12b) having a front mating end and a rear conductor receiving end. A stamped and formed metal shield (14a, 14b) surrounds at least the rear conductor receiving end of the insulating housing. The shield is formed by a pair of interengaging shield halves (14a, 14b). Each shield half has a semicylindrical portion (84) projecting from the rear end thereof and combining with the other shield half to form a cable crimping barrel. The barrel is formed by metal of each shield half being folded rearwardly from a front end (90) thereof, through an opening (91) in the rear end thereof, and thereby being integral with the remainder of the respective shield half. The insulating housing is formed by two interengaging housing halves (12a, 12b) defining a conductor receiving opening at the rear conductor receiving end of the housing. Interengaging cantilevered support beams (66a, 66b) are provided on the housing halves on opposite sides of the opening to provide lateral support for a cable and interengaging support for the housing halves themselves. | Field of the InventionThis invention generally relates to the art of electrical connectors and, particularly, to an electrical connector which has a shield assembly including an integral cable clamping means or crimp barrel. Background of the Invention There is an ever increasing demand for effective electrical shielding of electrical connectors in view of the continuing complexity and miniaturization of communication devices which are affected by electromagnetic and radio frequency interference. Such shielded connectors must be capable of manufacture and assembly with economical methods which are capable of adaptation to standardized connector configurations and sizes. Most such connectors include shield means which are readily stamped and formed from metal material complementary in shape to the profile of the shielded connector components. An example of a standardized connector configuration is a D-sub connector. Furthermore, such shielded connectors are interengaged with a multiconductor electrical cable which, itself, has shielding means such as a braided shield inside an outer insulating jacket of the cable. The shield of the cable should be conductively coupled to the shield means of the connector. This most often is carried out by cable clamping means, such as a metal crimp barrel which is crimped onto the shielding braid of the cable. For economic manufacture and assembly purposes, the crimp barrel often is formed integral with the stamped and formed shield means of the connector, at a rear end thereof. Whereas the shield means for the electrical connector is stamped and formed from metal material, heretofore the crimp barrel most often has been formed by a drawing process or at least partially drawn. There are distinct disadvantages of having a drawn portion of a shielding component of an electrical connector. First, the drawing process requires a thicker sheet of metal since drawing tends to thin the metal at the drawn areas. Second, the drawing process usually requires a triangular rather than a rectangular shape of the shielding component. In other words, the rear end of the shielding means angles toward the crimped cable on both sides thereof. When the connector components are overmolded with plastic material, the triangular shape requires the rectangular plastic overmold to fill large voids created by the tapered rear end of the shield. Third, a drawn crimp barrel is stiffer at the interface between the barrel and the rear end of the shield. Therefore, the actual crimping portion of the barrel usually is located rearwardly of the stiffer area of the barrel, requiring that the barrel be of an undue length. This is disadvantageous where miniaturization is a premium. In instances where there are size or envelope limitations, the drawn barrel provides a smaller transition section which makes the routing of the conductors between the terminals (often insulation displacement terminals) and the barrel more difficult. WO-A-8505230 discloses a connector having the features of the preamble of claim 1. DE-U-9002067 discloses a connector comprising two half shells forming a housing. A cable is clamped between the side walls of the half shells and transverse bars formed therebetween. DE-U-8027787 describes a connector with a housing and gripping means for clamping a cable. This invention is directed to solving the above problems by providing a shield means with a new and improved stamped and formed cable clamping means or crimp barrel. An object, therefore, of the invention is to provide a new and improved shielded electrical connector which has an improved cable clamping means. In the exemplary embodiment of the invention, the shielded electrical connector assembly includes an insulating housing means having a front mating end, a rear conductor receiving end and conductor receiving means for receiving conductors from a multiconductor cable projecting from the rear end of the housing means. Stamped and formed metal shield means are disposed about at least the rear conductor receiving end of the insulating housing. Stamped and formed cable clamping means are provided at a rear end of the metal shield means, integral therewith, and formed by metal of the shield means being folded rearwardly from a point remote from the rear end thereof. As disclosed herein, the metal shield means is provided by a pair of interengageable shield halves each having a metal portion folded rearwardly and combining to form the cable clamping means, preferably in the form of a generally cylindrical crimp barrel. The shield halves each have a front end, and the rearwardly folded metal portion which forms the crimp barrel is folded rearwardly from a front edge of the respective shield half, overlapping a major wall of the shield half and projecting rearwardly through an opening in a rear wall of the shield half. The insulating housing means of the connector assembly also is fabricated by a pair of interengaging housing halves. Rear walls of the halves have openings or recesses through which the conductors of the cable extend. A feature of the invention is to provide transversely projecting portions of each housing half interengageable with complementary projecting portions of the other half, on opposite sides of the conductor receiving opening. These projecting portions provide lateral support for the multiconductor cable and also provide support for the rear walls of the housing halves. Other objects, features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings. Brief Description of the DrawingsThe features of this invention which are believed to be novel are set forth with particularity in the appended claims. The invention, together with its objects and the following description taken in conjunction with the accompanying drawings, in which like reference numerals identify like elements in the figures and in which: FIGURE 1 is an exploded perspective view of a shielded electrical connector assembly incorporating the novel features of the invention; FIGURE 2 is a perspective view of a pair of insulation displacement terminals incorporated in the connector assembly; and FIGURE 3 is a perspective view of the electrical connector assembly having been overmolded with a plastic covering. Detailed Description of the Preferred EmbodimentReferring to the drawings in greater detail, and first to Figure 1, the illustrated shielded electrical connector assembly includes insulating housing means formed of three components; namely, a dielectric body, generally designated 10, and a pair of housing halves, generally designated 12a and 12b; a stamped and formed metal shell, generally designated 14; and stamped and formed metal shield means including a pair of shield halves, generally designated 14a and 14b. Housing body 10 can take a variety of configurations. The configuration shown includes a rear housing block 16, a peripheral flange 18 and a forwardly projecting table-like terminal positioning flange 20. In particular, referring to Figure 2 in conjunction with Figure 1, a pair of insulation displacement terminals 22a and 22b are shown oriented in opposite directions and including insulation displacement beams 24 and terminal contacts 26. The displacement beams 24 are at two levels and two rows creating a staggered orientation. A plurality of the insulation displacement beams are shown projecting upwardly from housing block 16 in Figure 1, and a plurality of terminal contacts 26 are shown disposed in appropriate grooves on top of forwardly projecting flange 20 for mating with terminals of a complementary connector assembly (not shown). It should be understood that although the top of housing body 10 is visible in Figure 1, the bottom of the housing body is substantially identical to the top. That is why two insulation displacement terminals 22a, 22b are shown in Figure 2 oriented in opposite directions. Both the top (visible in Fig. 1) and the bottom of peripheral flange 18 of housing body 10 have a pair of channels 28 with projecting pegs 30 in the channels (for purposes described hereinafter). In addition, a pair of passages 32 are formed in both the top and bottom of peripheral flange 18, again for purposes described hereinafter. The entire housing body 10 is integrally molded of plastic or other dielectric material. Metal shell 14 includes a peripheral flange 34 for abutting against a front face 36 of housing body 10. A D shaped flange 38 projects forwardly of flange 34 of the shell for receiving a portion of the complementary connector assembly. D-shaped flange 38 has a plurality of dimples 40 stamped toward the inside thereof to provide an effective electrical interconnection with the shield of the complementary connector. Metal shell 14 is assembled to housing body 10 by means of a pair of staking barbs 42 stamped and formed from both the top and bottom edges of flange 34 for insertion in and interengagement with passages 32 at the top and bottom of peripheral flange 18 of the housing body. Housing halves 12a, 12b are substantially identical to each other. In other words, the top or outside of housing half 12a is visible in Figure 1, but the bottom outside of housing half 12b is substantially identical thereto. Likewise, the top inside of housing half 12b is visible in Figure 1, but the bottom inside of housing half 12a is substantially identical thereto. Each housing half 12a, 12b has a locating post 44 for positioning within a locating hole 46 of the opposite housing half to facilitate assembly. Each housing half 12a, 12b has a pair of latch fingers 48 and a pair of latch bosses 50. The latch fingers are somewhat flexible and the latch bosses are rigid with the surrounding walls of the housing halves. After termination of the conductor 64 between the respective insulation displacement beams 24, the housing halves are moved toward each other in the direction of double-headed arrow A as they are guided by posts 44 into holes 46 and by projecting cantilevered support beam 66a contacting projecting cantilevered support beam 66b on the mating part,, whereupon latch fingers 48 of each housing half snap into interengagement with latch bosses 50 of the opposite housing half. In assembly, housing halves 12a, 12b are moved toward each other with housing body 10 sandwiched therebetween. Each housing half has a pair of forwardly protruding projections 52 with apertures 54 therethrough. Projections 52 seat in channels 28 in the top and bottom of peripheral flange 18 of the housing body, and pegs 30 in the channels engage apertures 54 in projections 52. This locates and secures the insulating housing means, including housing body 10 and housing halves 12a, 12b in assembled condition, as latch fingers 48 and latch bosses 50 hold the components in assembly. Housing halves 12a, 12b can be termed conductor management blocks in that they include a plurality of laterally spaced ribs 56 defining conductor receiving troughs therebetween. Rear walls 58 of the housing halves include semicircular notches 60 which combine to define a circular opening for receiving a multiconductor cable 62. Individual conductors 64 (only two of which are shown in Fig. 1) extend from cable 62 and are positionable within the troughs defined by ribs 56. This locating means guides the conductors into the insulation displacement beams 24 of insulation displacement terminals 22a, 22b. A feature of the invention contemplates the provision of projecting cantilevered support beams 66a and 66b on opposite sides of semicircular notch 60 on each housing half 12a, 12b. It can be seen in Figure 1 that a cut-out 68 is formed at the base of beam 66b. A similar cut-out (which is not visible in Figure 1) is formed on the rear side of beam 66a. Consequently, when housing halves 12a, 12b are assembled, the beams are positioned closely adjacent each other with the distal ends of the beams extending into cut-outs 68. The beams provide a dual function. First, they provide lateral support for cable 62, particularly during locating conductors 64 between ribs 56 and prior to assembly of the housing halves. Second, the beams also provide additional support for rear wall 58 of the housing halves when interengaged. In other words, through the beams, the rear wall of one housing half can provide additional support for the rear wall of the other housing half. Shield halves 14a, 14b also are mirror images of each other. In other words, the outside top of shield half 14a is visible in Figure 1, but the outside bottom of shield half 14b is substantially identical thereto. Likewise, the top inside of shield half 14b is visible in Figure 1, but the bottom inside of shield half 14a is substantially identical thereto. Each shield half 14a, 14b includes a main transverse (top or bottom) wall 70, side walls 72 and a rear wall 74 combining to form a generally rectangular configuration. The side walls and the rear wall include projecting detent and aperture means 76 stamped and formed from the metal thereof to provide a snapping interengagement of the shield halves when moved together in the direction of double-headed arrow A . The shield halves are sized or dimensioned to substantially cover housing halves 12a, 12b when they are assembled as described above. In assembly, each shield half is provided with hooked cantilevered tabs 80 which interengage with slots 82 in peripheral flange 34 of metal shell 14 when the assembled shield halves are pivoted in the direction of arrow B . Shield halves 14a, 14b are fabricated of stamped and formed metal material. The invention contemplates a novel cable clamping means, generally designated 84, on each shield half 14a, 14b which, when assembled, forms a crimp barrel for crimping onto a braided shield or ground (not shown) of multiconductor cable 62. As stated above, the shield means or crimp barrel forms a stamped and formed clamping means which does not have the disadvantages of prior drawn crimp barrels. More particularly, a front-to-rear elongated tongue 86 (see shield half 14b) is stamped and formed integrally with each shield half and is bent, as at 88, from a front edge 90 of wall 70, with the tongue being folded rearwardly inside the wall toward and through a semicircular opening 91 in the rear wall 74 of each shield half. It can be seen by shield half 14a, that wall 70 is stamped with an outwardly projecting trough 92 so that tongue 86 lies substantially flush with the inside surface of wall 70. The tongue of each shield half (see shield half 14b) is provided with a cut-out 94 to accommodate the center hooked cantilevered tab 80 which interengages with metal shell 14. Cable clamping means 84 is stamped and formed at the distal end of tongue 86 as best seen by shield half 14b. Specifically, the distal end of each tongue 86 is enlarged and curved, as at 96, to form one-half or semicylindrical portion of a composite crimp barrel disposed rearwardly or on the outside of rear wall 74 of the respective shield half. In other words, the stamped and formed semicylindrical shape at the distal ends of the respective tongues of shield halves 14a, 14b abut in an edge-wise manner to form an enclosed crimp barrel. The crimp barrel, being stamped and formed from the same metal sheet as the entirety of the shield halves, therefore can have a uniform thickness, and thereby afford a rectangular configuration for the shield halves as described above in the Background. Once the shield halves are interconnected about the assembled housing halves 12a, 12b, the crimp barrel can be crimped onto the braid of cable 62 which is wrapped around and supported by cylindrical ferrule 63, and the crimped area can extend throughout the barrel. Again as visible with shield half 14b, a plurality of tabs 100 are stamped from the metal material of each shield half at the forward edge (when formed as shown in Fig. 1) of cable clamping means 84. These tabs are bent transversely outwardly into engagement with the inside surface of rear wall 74. The tabs provide additional shielding in the void between semicircular opening 91 in rear wall 74 and the outer surface of the crimped barrel. In addition, the tabs provide additional support for the crimp barrel and direct contact circumferentially about the crimp barrel with rear wall 74 which forms an integral portion of the main structure of the integral shield halves. After connector components 10, 12a, 12b, 22a and 22b are assembled as described above, shield halves 14a and 14b are assembled over the housing components, and cable clamping means 84 are crimped onto cable 62, an overmold 102 (Fig. 3) is molded over the assembly in a generally rectangular configuration. The present examples and embodiments are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein. | A shielded electrical connector assembly, comprising: insulating housing means (12a, 12b) having a front mating end and a rear conductor receiving end for a multiconductor cable (62); stamped and formed metal shield means (14a, 14b) about at least the rear conductor receiving end of the insulating housing; and cable clamping means (84) at a rear end of the metal shield means (14a, 14b) integral therewith, characterized in that the metal shield means (14a, 14b) comprises a tongue (86) extending from a point (88) of the metal shield means (14a, 14b) remote from the rear end thereof and folded back to said rear end, and the rear distal end (96) of the tongue forming the cable clamping means (84). The shielded electrical connector assembly of claim 1 wherein said cable clamping means (84) is generally cylindrical. The shielded electrical connector assembly of claim 1 wherein said metal shield (14a, 14b) means comprise a pair of interengageable shield halves each having a tonque (86) folded rearwardly the tongues (86), combining to form said cable clamping means (84). The shielded electrical connector assembly of claim 3 wherein the rear distal ends (96) of the tongues (86) are semicylindrical to combine and form the cable clamping means (84) in a generally cylindrical configuration. The shielded electrical connector assembly of claim 1 wherein said shield means (14a, 14b) has a front end (90), and said tongue (86) extends from said front end. The shielded electrical connector assembly of claim 5 wherein said shield means has a rear wall (74) and said cable clamping means (84) projects through an opening (91) in the rear wall. The shielded electrical connector assembly of claim 6 including support tabs (100) bent transversely outwardly from the cable clamping means (84) against an inside surface of the rear wall (74). The shielded electrical connector assembly of claim 5 wherein said rearwardly folded tongue (86) is located inside a wall (70) of the shield means. The shielded electrical connector assembly of claim 8 wherein said wall (70) has an outwardly projecting recess (92) to accommodate said tongue (86) so that the tongue lies flush with an inside surface of said wall. The shielded electrical connector assembly of claim 1 wherein said metal shield means (14a, 14b) is substantially rectangular in configuration. An electrical connector assembly according to one of claims 1 to 10 characterized in that said insulating housing means formed by a pair of interengageable housing halves (12a, 12b), the housing means having a rear conductor receiving opening (60); and each of said housing halves having a cantilevered support beam (66a, 66b) on each side of said opening (60), projecting toward the other housing half to provide lateral support for a conductor (62) extending through said opening (60). The electrical connector assembly of claim 11 wherein the support beams (66a, 66b) of said housing halves (14a, 14b) on each respective side of said opening (60) are positioned in abutment with each other to provide engaging support between the housing halves. | MOLEX INC; MOLEX INCORPORATED | LOPATA JOHN E; SMITH JAMES; LOPATA, JOHN E.; SMITH, JAMES |
EP-0490089-B1 | 490,089 | EP | B1 | EN | 19,960,904 | 1,992 | 20,100,220 | new | F04B49 | F25B49, H02P6 | F04B39, F04B49, F25B49 | F04B 49/20, F04B 39/10R, F25B 49/02C | Improvement in refrigeration compressors with electronic control arrangement | Hermetic reciprocating compressor (10) for refrigerators and freezers, driven by a brushless-type electric motor (17) and provided with a frequency control arrangement (18) to let the motor run at any speed that is compatible with a correct operation of the compressor (10), in order to achieve an increase in the overall efficiency, a reduction in the operating noise and a reduction in the energy consumption of the compressor. The new compressor design makes it possible to standardize and reduce the number of compressor models which are required to cover a broad application range in refrigeration appliances. | This invention relates to an improved refrigeration compressor with electronic control arrangement, in particular a reciprocating, hermetic-type compressor for domestic refrigerators and freezers. Currently, this type of compressors is provided with an electric induction motor operating under an on-off type of control at such rotation speed rates as determined by the existing electric line frequency, ie. 50 Hz or 60 Hz. Under these conditions, the refrigerating capacity, given an equal amount of refrigerant fluid used, is therefore determined mainly by the displacement, ie. swept volume, of the compressor. Furthermore, it should be noticed that, even when adding a running capacitor, the efficiency of an induction motor does not exceed a value of 0.8. It should also be noticed that the penetration rate of combined refrigeration appliances with separate fresh-food and frozen-food compartments served by a single refrigerating circuit with a single compressor is continuously increasing. In view of their ability to cope with the energy demand peaks resulting in connection with the need of freezing down the maximum allowable load of food in the corresponding freezing compartment, these appliances must be equipped with a correspondingly rated compressor, ie. a compressor having a higher power rating than normally required for regular operation, adequately sized to suit the highest energy demand for freezing. As a consequence, when the appliance is operating normally in view of only pulling down the temperature in the fresh food compartment, the compressor actually turns out to be overrated, ie. oversized, and uses a considerable amount of energy owing to the repeated, frequent cycling of the compressor. As it is widely appreciated, energy saving through increasing efficiency records of household appliances is a primary target of appliance manufacturers, who have been imposed well-defined energy consumption limits in several countries and are therefore confronted with the need of keeping below said limits. Finally, a further requirement in connection with all types of appliances intended for home use derives from the need which is generally felt of reducing the operating noise of such appliances as far as feasible. GB-A-2133586 refers to a refrigerator circuit having a microprocessor based control unit which operates a compressor-motor through a frequency converting unit. However, said solution is complicated because it requires a continuous temperature control based on the difference between the interior temperature of the refrigerator and a predetermined reference temperature. It is the purpose of this invention to provide a compressor for refrigerating and freezing appliances which is able to do away with the typical disadvantages and overcome the limitations of current compressors. In particular, the improved compressor with electronic control arrangement according to this invention can be used in association with any refrigerating circuit, thereby enabling the overall efficiency rating to improve, the noise to be reduced and the energy consumption to be considerably decreased. The innovatory features of the compressor according to this invention are as defined and delineated in the herein appended claims. The aims and the advantages of the invention will be further described by way of non-limiting example with reference to the accompanying drawings, in which: Figure 1 is a schematic view of a refrigerating circuit provided with motor-compressor with electronic control arrangement according to the invention; Figures 2 through to 5 are the views of respective operating diagrams of the motor-compressor with electronic control arrangement shown in Figure 1; Figure 6 is a partial schematic cross-sectional view of the cylinder of a modified motor-compressor in view of its utilization according to the invention. The refrigerating circuit which is schematically shown by way of example in Figure 1 comprises a compressor 10, a condenser 11, a collector 12 for the liquid refrigerant fluid, a filter-dehydrator 13, an expansion valve 14, and two evaporators 15 and 16, connected in series, for the frozen-food compartment and the fresh-food compartment, respectively. According to the invention, the compressor 10 is driven by a motor 17 of the brushless type, which is controlled by a frequency control arrangement 18 of a generally known type. Said frequency control arrangement 18 is connected with a temperature sensor 19, preferably a thermistor, which senses the temperature of the evaporator 16 of the fresh-food compartment. Furthermore, said frequency control arrangement 18 comprises a microprocessor adapted to set, in a preferable way, two different operating frequencies, ie. a lower frequency corresponding to the highest overall efficiency of the compressor for the operation of the refrigeration appliance under normal refrigeration capacity demand conditions, and a higher frequency for the operation of the appliance under increased refrigeration capacity demand conditions, in particular when the need arises to freeze a considerably large amount of food in the frozen-food compartment. The invention covers therefore the proposal of utilizing, for a compressor of a given refrigerating capacity, a larger displacement and a motor of the brushless type tuned on a lower frequency than the usual 50-Hz or 60-Hz mains frequency, in such a way that the overall compressor efficiency (COP) is increased and the compressor noise is reduced. In fact, as anyone skilled in the art already knows, the volumetric efficiency of a compressor improves as its displacement is increased, since the relative influence of clearances, dead or passive spaces is decreased. These clearances or dead spaces are formed, among other things, by the volumes of the suction and delivery bores in the valve plates. A further known fact is the improvement of the volumetric efficiency of a compressor with the decrease of the RPM, ie. the rotation speed of the motor, since this volumetric efficiency mainly depends on the clearance volume at the top dead center, the heating up of the suction gas, the blow-by losses and the opening and closing lags of the valves. On the other hand, said opening and closing lags of the valves are much less influential at the lower frequencies since they occur at a lesser rate. Quite easy to understand is furthermore the fact that, by supplying the electric motor driving the compressor with power at a reduced frequency, it will generate less heat and, as a consequence, will transfer a smaller amount of heat to the suction gas. Finally, the volumetric efficiency can be improved through a reduction in both the clearance or passive volume and the load losses by correspondingly sizing the passage cross-section of the delivery and suction bores in the plate of the valves, while keeping flow rates unaltered. In addition to that, the mechanical efficiency improves as the motor RPM decreases, since it is known that relative losses increase as a function of the motor RPM. Figure 2 shows the curve relating to the overall efficiency coefficient (COP) of a compressor versus the displacement volume (cc) of the same compressor. Quite similar is on the other hand the profile of the curve relating to the overall efficiency coefficient (COP) versus the capacity for a given compressor. Figure 3 shows the curves of the volumetric efficiency (η1) and the efficiency relating to the load losses through the discharge bore in the valve plate (η2) versus the bore diameter (), for compressors having different displacement ratings and driven at different motor RPMs. It is a known fact, and it also ensues from the configuration of the curves shown in the Figures, that the two afore mentioned types of efficiency have contrasting characteristics, ie. progress in a contrasting way, so that the optimum sizing of the bore diameter has to be selected in correspondence of the highest value of the product of the two afore mentioned efficiencies. In particular, this generally occurs in correspondence of the point at which the two curves relating to the characteristic data (ie. displacement and RPM) for each compressor meet. Figure 4 shows the curve of the overall efficiency coefficient (COP) of a compressor versus the motor RPM, from which it clearly emerges that the efficiency reaches its highest value in correspondence of a well-defined motor RPM. Figure 5 finally is a three-dimensional diagram showing the curves obtained experimentally in view of optimizing a compressor according to the invention, in order to determine the highest attainable efficiency versus the motor RPM and the diameter of the bore of the discharge or delivery valve. Figure 6 shows the partial cross-section of a hermetic reciprocating compressor, in which a number of components, ie. the cylinder-piston assembly 21, the valve plate 22, the valve 23, the delivery or discharge bore 24 and the muffle 25, are illustrated in detail. From Figure 5 it clearly ensues that, by using a brushless motor provided with a frequency control arrangement to drive the compressor and modifying in a suitable way the dimensions of the bore of the delivery valve, it is possible to identify the optimum sizing and operating characteristics of the compressor by just moving along the ridge formed by the peak values in the curves shown. Two examples of optimum sizing of two experimentally designed compressors having different characteristics are illustrated hereinafter. First exampleLet us consider two compressors equipped with induction motors of current production and having different displacement volumes, ie. a 3.6-cu.cm compressor A and a 3.8-cu.cm compressor B. Their respective characteristics and performance data are as follows: Compressor A:Motor rotation speed (RPM)2875 rpm Refrigerating capacity74.8 Kcal/hr Power input rating94.5 W COP0.92 Compressor B:Motor rotation speed (RPM)2870 rpm Refrigerating capacity57.2 Kcal/hr Power input rating71.0 W COP0.88 Now, if we take compressor A and replace its induction motor with a brushless motor, in particular of the variable reluctance type, and, based on the curves shown in Figure 5, we further determine the motor RPM at which the compressor modified in the above described way will be able to deliver a refrigerating capacity which is equal to that delivered by compressor B, following values will be found: Furthermore, the reduction in the motor RPM (ie. from 2875 to 2100 rpm) causes the flow rate to decrease accordingly, so that it will be possible and appropriate to downsize the diameter of the bores of the valves. If we therefore, again based on the curves shown in Figure 5, identify the COP optimizing diameter of the bore of the delivery valve, it will be found that such a diameter (measuring 3.2 mm in compressor A) can be downsized to just 2.5 mm in the corresponding modified compressor. Through this measure, the COP of this compressor will then increase to 1.15, while the refrigerating capacity will go up to 58 Kcal/hr (which is even a higher capacity than that of compressor B). In other words, what we have achieved in this way is a plain increase of the COP by more than 30 percent. When repeating this same experiment substituting a brushless permanent-magnet electronically commutated motor for the induction motor, still better results are achieved. As a matter of fact, the COP achieved in this way is as high as 1.25, which means a 42-percent increase over the COP of the original compressor B equipped with standard induction motor. Even noise measurements give remarkably improved results, since the sound emission level actually decreases from 35.7 db(A) to 34.2 dB(A), while the vibration figure is at the same time slashed from 32.2 dB(A) to 27.0 dB(A). Second exampleLet us now take a current-production compressor having a displacement volume of 4.4 cu.cm and driven by an induction motor. Its characteristics are: Motor rotation speed (RPM)2890 rpm Refrigerating capacity88.0 Kcal/hr Power input rating99.0 W COP1.03 If we now use a compressor with a larger displacement volume, ie. 5.9 cu.cm, driven by a brushless, electronically commutated permanent-magnet motor, following values are achieved: Motor rotation speed (RPM)2000 rpm Refrigerating capacity81.5 Kcal/hr Power input rating73.3 W COP1.29 If at this point also the valve plate undergoes an optimization process in accordance with the lower motor RPM, it ensues that, with delivery and suction bores having a diameter of 2.5 mm each (instead of two bores with a diameter of 3.2 mm each), the refrigerating capacity becomes 86 Kcal/hr (ie. practically equivalent to the capacity of the unmodified compressor), while the COP jumps to 1.33 with an increase of 29.1 percent. Even the noise figure of the compressor is in this way improved, since it decreases from 38.2 dB(A) to 36.0 dB(A). The same applies to the vibratory behaviour, since oscillations appear to fall from 35 dB(A) to 28 dB(A). It may therefore be concluded that the compressor with brushless-type motor with electronic frequency control according to the invention actually achieves the scopes and the purposes of the invention by enhancing the efficiency, lowering the noise and reducing the energy consumption in a very effective way. It should also be emphasized how, by using an electronic frequency control employing a microprocessor, it is actually possible to even pre-set, for the motor power supply, more than two differently reduced frequencies, without however departing from the range of highest overall efficiency of the compressor. As a consequence, the compressor according to the invention can be used to equip appliances implying different refrigerating capacities. This again translates into the further advantage of enabling the number of compressor models, which are required to cover a broad application range in refrigeration appliances, to be standardized and reduced. | Hermetic reciprocating refrigeration compressor, in particular for household-type refrigerating and freezing appliances, provided with an electric drive motor (17) and an electronic control arrangement (18), characterized in that said motor (17) is a brushless-type motor and said control arrangement (18) is a frequency control arrangement adapted to operate said motor at two different speeds in order to set a first operating frequency corresponding to the highest overall efficiency of the compressor, the same frequency control arrangement (18) being also adapted to operate the motor (17) at a second frequency higher than the first one, so as to operate the refrigeration appliance under conditions of a higher refrigerating capacity demand. Hermetic reciprocating compressor according to claim 1, characterized in that the supply frequency of said motor (17) is reduced so as to maximize the overall efficiency of the compressor (10) with a rotational speed of the motor which is lower than that of a corresponding induction motor. Hermetic reciprocating compressor according to claim 1 or 2, characterized in that the delivery and suction bores (24) provided in the plate (22) of the valves of the compressor (10) have a diameter which is reduced in proportion to the reduced number of revolutions per minute of the compressor motor, so as to improve the overall efficiency and optimize the refrigerating capacity of the compressor with a reduction in the clearance volume in the compression chamber. Hermetic reciprocating compressor according to any preceding claim, characterized in that said compressor (10) has a larger displacement volume than that of a compressor driven by an induction motor for a corresponding refrigerating capacity. | ZANUSSI ELETTROMECC; ZANUSSI ELETTROMECCANICA S.P.A. | BELLOMO MATTEO; BELLOMO, MATTEO |
EP-0490095-B1 | 490,095 | EP | B1 | EN | 19,970,917 | 1,992 | 20,100,220 | new | G02B6 | null | G02B6 | G02B 6/13 | A process of manufacturing an elongate integrated optical device with at least one channel therein | A method of manufacturing planar optical waveguides in which a planar optical preform which is stretched to form a planar optical cane with substantially smaller cross-sectional dimensions than the original preform, and in which the optical circuitry pattern is achieved by lithographic techniques. Optical fiber preforms may be inserted in slots in a substrate to form the planar optical preform. | This invention relates to a process of manufacturing an elongated integrates optical device with at least one channel waveguide therein. Devices of the aforementioned type are used as passive components in optical inter-connection systems. They are distinguished from cylindrical dielectric waveguides, e.g. optical fibers, in that they are substantially rectangular in cross-section. Existing methods for their manufacturing generally are expensive, require tight manufacturing controls, and result in devices with optical losses that are relatively high when compared to optical fibers. Existing methods of producing such devices involve the use of substrates having a first refractive index and having the preselected final dimensions of the device to be formed. Materials having a second refractive index different from that of the substrate are applied to the substrate using various methods, including standard soot deposition techniques which are well-known in the art. (See, e.g. Keck et al. U.S. Patents 3,806,223 and 3,934,061.) The preselected refractive index differential is achieved by using silica doped with one or more of the following: titanium oxide, tantalum oxide, tin oxide, niobium oxide, zirconium oxide, aluminum oxide, lanthanum oxide, germanium oxide, or other suitable refractive index modifying dopant materials. Optical circuitry within these devices is typically formed by a lithographic process similar to that used in the manufacture of semiconductor devices, as described in Izawa et al. U.S. Patent 4,425,146. Another prior art method is described in Hudson U.S. Patent 3,873,339 wherein a focused laser beam is used to fuse only that material which is to form part of the preselected optical circuitry, and the remaining unfused material is removed by cleaning or etching. Attention is also directed to JP-A-62-204207, which describes the formation of an integrated planar waveguide by stretching a preform, and further describes the transforming of the integrated planar waveguide into a desired integrated pattern of channel waveguides by means of photolithography. The use of lithographic techniques is wide-spread in the manufacture of semiconductor devices. These techniques are useful because detailed patterns - in the case of the present invention, optical circuit patterns - may be produced. The lithographic process begins with a structure which contains the necessary materials to produce the desired electrical or optical circuit. This structure is coated with a photo-resistive material. The photo-resistive material is exposed to light through a mask which selectively exposes part of the photo-resistive material. The mask is the image of the desired circuit pattern. The exposed photo-resist is developed in a developing solution designed for the type of photo-resistive material used. The underlying structure is then etched using, for example, reactive ion etching to transfer the mask pattern to the underlying structure. In the case of producing devices with a channel waveguide therein, a coating of alloy material, for example chrome, is typically applied to the underlying structure before the photo-resistive material is applied. This chrome layer is required because the photo-resistive material alone is not, in general, able to withstand the etching conditions necessary to etch the optical circuit into the underlying glass structure. The photo-resistive material is exposed and developed as above and the optical pattern is transferred to the intermediate chrome layer by using a chrome etching solution. Then the optical pattern is transferred to the underlying glass structure using, for example, reactive ion etching. Each of these existing methods involves the application of very thin layers to form the core region of the waveguide. This core region guides the majority of the light through the waveguide. Small perturbations in the manufacturing process may result in inhomogeneous core structures with optical losses which are very high, particularly relative to the optical fibers which are attached to these planar optical waveguides. Therefore, tight control of the deposition process is required in existing methods to achieve the preselected thickness of the core region. This is particularly the case where the channel waveguide is manufactured for use in single-mode systems using fibers with core diameters of 10 um or less. The problems inherent in existing methods of producing channel waveguides are: 1. optical losses are relatively high compared to those of optical fibers; 2. expensive manufacturing controls are required to keep the optical losses to a minimum; and 3. design and geometries are limited. According to the present invention there is provided a process of manufacturing an elongate integrated optical device with at least one channel waveguide therein, comprising: (a) forming an elongate fused glass structure of substantially rectangular cross-section comprising a first glass (1) having a first refractive index; (b) removing material from at least one longitudinal portion of a surface of said elongate glass structure to form at least one longitudinally extending groove therein; (c) placing in said at least one groove, at least one second glass having a second refractive index which is higher than said first refractive index so as to provide at least one channel waveguide in the device to be manufactured; and (d) heating and longitudinally stretching the resulting assembly to reduce the cross-section thereof, thereby resulting in said elongate integrated optical device with said at least one channel waveguide therein. Step (b) is preferably carried out using lithographic techniques. In one embodiment of the invention, the channel structure is formed by placing at least one optical fiber preform into the said at least one groove. In the ensuing description, the phrase planar optical cane is used to refer to a structure produced by stretching a consolidated body having a preselected refractive index profile, such that the cross-sectional dimensions of said consolidated body are reduced and the body is present proportionately in the planar optical cane after it is stretched. In the accompanying drawings: FIG. 1 is an illustration of a substrate with handles attached for support during processing. FIGS. 2-8 are cross-sectional views of a planar optical waveguide in various stages of manufacture. FIG. 9 depicts an example of an optical circuit pattern of a type of planar optical waveguide. FIGS. 10(a) and 10(b) depict an embodiment of the invention. FIGS. 11(a), 11(b), 11(c), 12 and 13 depict an alternative embodiment of the invention. FIGS. 14(a) and l4(b) depict other alternative ways of making optical waveguides. FIG. 15 shows the provision of cross-connect patterns in a core layer. FIGS. 16(a) and 16(b) are sectional views on line A-A in FIG. 15 of two optical fibers which can be used. The methods illustrated by FIGS. 1 to 9 and 14 to 16 are not within the scope of the claims, but are believed to provide helpful background information. The drawings are not intended to indicate scale or relative proportions of the elements shown therein. The process of FIGS. 1 to 9 begins with a substrate 1 as shown in FIG. 1. The substrate is essentially planar with dimensions substantially greater than those desired for the final integrated optical device with a channel waveguide therein. The material of the substrate is selected to match the thermal and mechanical properties of the materials used as waveguide conductors and films. Typically, the substrate will be made essentially of silica. However, with waveguide conductor materials containing some of the fluoride compositions, it is possible to use borosilicate or soda lime glass as the substrate material. Handles 2 and 3 may be attached to facilitate handling during the manufacturing process. The next step in the process is the application to a surface of the substrate of one or more layers of material having a refractive index different from that of the substrate. The preselected refrative index differential typically is achieved by using for these layers silica doped with one or more of the following: titanium oxide, tantalum oxide, tin oxide, niobium oxide, zirconium oxide, aluminum oxide, lanthanum oxide, germanium oxide, fluorine, or other suitable refractive index modifying dopant material. Dopants for other purposes may also be used, for example erbium or neodymium for amplification of an optical signal. In addition, other compositions such as fluoride glasses may be used for the layers and substrates may be formed from Pyrex glass, soda lime glass, etc., to match the thermal and mechanical properties of the waveguide conductor materials. The soot may be applied using standard soot generation techniques and may be applied on only one side or, by rotating the substrate, on all sides. The layers of material so applied preferably consist of a barrier layer 4, core layer 5, and clad layer 6 as shown in FIG. 2. Other techniques may be used to apply the material layers on the substrate, such as plasma-enhanced CVD, sol gel, low pressure CVD or sputtering. Whether barrier layer 4 is used depends on the refractive index and loss characteristics of the substrate 1. If the refractive index differential between substrate 1 and core layer 5 is too small, the material of the barrier layer 4 is selected such that the refractive index differential between the barrier layer and the core layer is sufficient to channel the majority of the light incident on the resulting integrated optical device through core layer 5. The refractive index of clad layer 6 is also selected to enable efficient waveguide propagation through core layer 5. A method within the scope of the claimed invention for this application step is the use of sol-gel or slurry casting techniques to place applied material 11 in dimensional grooves 10 cut into the surface of substrate 1 as shown in FIG. 10(a). The dimensional slots are cut in the surface of the substrate using lithographic techniques or a dicing saw, depending for example, on the size of the slots. After the material is applied, the structure is heated in a furnace to fuse the refractive index producing material and provide a planar optical preform. This fusing process should preferably occur quickly to reduce the diffusion of dopants in the various layers of soot. This fusion step may be performed in a chlorine atmosphere if it is desirable to dehydrate the soot layers. An example of this dehydration process is described in more detail in U.S. Pat. No. 4,165,223 issued to D. R. Powers. The fused structure is then heated to the softening point and stretched to produce a planar optical cane of the preselected end dimensions. The reduction ratios typically involved are 50:1 or less, with a preferred range of 10:1 to 20:1. The softening temperatures and the aspect ratio (i.e., width to height) of the fused structure should be chosen so as to avoid geometric distortion during the reduction step. Rounded corners, as shown in FIG. 3, may be used instead of sharp features to reduce the geometric distortion. The preselected optical circuitry is then produced on the planar optical cane using lithographic techniques. A metal or alloy coating material 7 and an organic photo-resist coating 8, shown in FIG. 4, are applied to the planar optical cane. Thereafter, a master mask is aligned over the planar optical cane, and the pattern of the master mask is transferred to the organic photo-resist coating by conventional photo-lithographic techniques. The exposed organic photo-resist coating is removed by washing the planar optical cane in developing solution, and the alloy coating in these exposed areas is removed using a commercial chrome etch solution. After these coatings are removed, the only coatings remaining on the planar optical cane are in the pattern of the master mask, for example as shown in FIG. 5. Any remaining organic photo-resist material is removed by washing in acetone. The pattern is then transferred onto the planar optical cane, for example as shown in FIG. 6, by reactive ion etching. As depicted in Fig. 9, the etching step may be carried out such that, after etching has been completed to remove the unwanted portions of said second glass, relatively wide portions 32 of the unetched cane remain at the lateral edges of the planar optical waveguide. Preferably, etching is carried out to remove 15-30µm wide trenches 33 adjacent the waveguide paths 15, 16 and 17. These portions help to protect the preselected optical circuitry from physical damage during further processing. Any remaining alloy coating is removed using a commercial chrome etch solution. An overclad layer 9, for example as shown in FIG. 7, is applied to the planar optical waveguide using conventional soot deposition techniques or other thin film technologies such as plasma-enhanced CVD, sol-gel, low pressure CVD or sputtering. Preferably, the substrate is a fused silica slab with a refractive index of 1.458 and initial dimensions of 12.7 mm (½ inch) thick by 50.8 mm (2 inches) wide by 356 mm (14 inches) long. The substrate is shaped and ground to essentially a rectangular cross-section using conventional glass grinding techniques. Handles 2 and 3 (FIG. 1), made for example of T08 (commercial grade silica) rod, are attached to the substrate by fusing the handles to the substrate under open flame. These handles allow the substrate to be mounted in a glass-working lathe. The glass-working lathe is equipped with burners to carry out a flame hydrolysis/oxidation process similar to that described in U.S. Pat. No. 2,272,342 issued to J. F. Hyde and U.S. Pat. No. 2,326,059 issued to M.E. Nordberg. Conventional vaporizer or bubbler equipment is used to deliver the chemical reactants to the burner (see, Blankenship U.S. Patent No. 4,314,837 and Schultz U.S. Patent No. 3,826,560). The burner is similar to that described in Moltzan U.S. Patent No. 3,698,936; a discussion of the temperature characteristics of the flame produced by such burners may be found in M. Elder and D. Powers, Profiting of Optical Waveguide Flames , Technical Digest for the 1986 Conference on Optical Fiber Communication, Atlanta, Georgia, page 74, 1986. A barrier layer 4, as shown in FIGS. 2-7, is not required because the substrate is fused silica and has the necessary refractive index in relation to the refractive index of the core layer 5. A cross-section of the cane used in this example, without a barrier layer, is shown in FIG. 8. References to FIGS. 2-7 in describing the lithographic process used in this example will be made for convenience only, as FIGS. 2-7 show a barrier layer which is not present in this example. A core layer 5 (FIG. 8) approximately 100 µm thick, consisting of SiO2 and 8% by weight GeO2, with a refractive index of approximately 1.464, is applied to the substrate. Thereafter a clad layer 6 of pure silica soot approximately 100 µm thick is applied over the core layer. The resulting structure is placed in a furnace at a temperature of approximately 1540 degrees C for approximately 20 minutes to fuse the core and clad layers. The fused structure is then placed in a vertical furnace and heated to approximately 2100 degrees C. This second furnace is equipped with gripping and pulling mechanisms which stretch the fused structure. The fused structure is lowered into a hot zone in the furnace which raises the temperature of the fused structure to the softening point. The pulling mechanism then stretches the fused structure by pulling the bottom of the structure out of the hot zone of the furnace at a rate which is faster than the rate at which the fused structure is being lowered into the hot zone. The fused structure is thereby stretched such that its length is increased while its width and thickness are decreased. The planar optical cane thus produced is approximately 4 mm (0.16 inches) wide, 1 mm 0.04 inches thick, and 762 mm (30 inches) in length. The resulting thickness of the core layer of glass is 6-8µm. In another alternative, the core layer may be 8-9µm thick. The number of individual optical devices which can be produced from one planar optical cane is dependent on the type of device to be produced. For example, a 3 dB splitter, as shown in FIG. 9, is approximately 25.4 mm (1 inch) in length; therefore, one planar optical cane with stretched width corresponding to the device width would yield approximately 30 such devices. The planar optical cane is repeatedly cleaned in a solution of de-ionized water, acetone and 1-2% HF. A chrome coating 7, such as Chrome Target made by Materials Research Corporation, located in Orangeburg, NY 10962 approximately 2000 Angstroms thick is applied to the planar optical cane using RF-sputtering techniques. Thereafter, organic photo-resist coating 8, such as S1400-17 made by the Shipley Company, located in Newton, MA, is spin coated on the chrome surface at 3000 rpm. The coated planar optical cane is then baked in an oven at 110 degrees C for 20 minutes. Using conventional techniques, a master optical circuitry mask is prepared with the preselected optical circuitry pattern. An example of such an optical circuit pattern is depicted in FIG. 9. The optical pattern of this example results in a device known as a 3 dB splitter. Light enters the device at input 15. Part of the light exits at output 16 and part at output 17. The coated planar optical cane may be fed into a lithography machine. The machine aligns the cane with the master optical circuitry mask and exposes the organic photo-resist coating to ultraviolet light. The preselected optical circuitry pattern is thereby transferred to the organic photo-resist coating. The pattern is developed in the organic photo-resist coating using photo-resist developer, such as Microposit 352 developer made by the Shipley Company, located in Newton, MA. The coated cane is rinsed in de-ionized water and dried. Also, the exposed positive organic photo-resist coating is removed during this step. The chrome coating at the exposed areas of the planar optical cane is removed using a commercial chrome etch solution, such as Chrome Etch made by KTI Chemicals, Inc., located in Sunnyvale, CA. Thereafter, the remaining organic photo-resist coating is removed by washing the planar optical- cane in acetone, rinsing in de-ionized water and drying. As a result, the planar optical cane has chrome coating in the pattern of the preselected optical circuitry. The unprotected glass portions of the planar optical cane are then etched using a reactive ion technique. The remaining chrome coating is removed using a commercial chrome etch solution. The planar optical cane is then scrubbed in a solution of de-ionized water, commercial glass cleaner and 1-2% HF, rinsed in de-ionized water and dried. Thereafter, at least approximately 15µm of overclad layer 9 (FIG. 7) is applied over the optical circuitry by conventional soot deposition techniques. If passive alignment to pigtail arrays is desired, approximately 62.5µm of overclad layer 9 should be applied. The overclad layer is silica doped with approximately 8% by -weight of B2O3 to reduce the fusing temperature and doped with approximately 1% by weight GeO2 to result in a refractive index of approximately 1.458. To form waveguides other than for single mode operation at 1.3-1.55µm, the dopant levels should be adjusted appropriately. This cladding material is fused to the planar optical waveguide at a temperature of approximately 1320 degrees C for approximately 20 minutes to assure that the cladding layer covers the optical circuitry without leaving any voids. Integrated optical devices made as described above have shown improved optical performance. Attenuations, including coupling losses induced during the measurement, have been measured as low as 0.02 dB/cm. After accounting for the theoretical coupling losses attributable to the measurement equipment, the calculated attenuations of some of the devices produced by the above process are less than 0.01 dB/cm. This compares to attenuations of 0.05-0.1 dB/cm with prior art processes. This substantial attenuation reduction is believed to result from the smoothing and size reduction of defects during redraw. More than one integrates optical device may be combines in the optical circuitry pattern. Also, it is possible to process a series of integrated optical devices by successively exposing portions of coated planar optical canes using a master lithographic pattern. Another alternative possibility is the processing of longer length planar optical canes by feeding the cane into a device which will successively expose areas of this cane to preselected optical circuitry master masks. This is illustrated in FIG. 14(a) where a longer planar optical cane 22, coated with a chrome coating 7 and an organic photo-resist coating 8, is moved into a machine which aligns successive areas of said longer planar optical cane 22 to master mask 23 for exposure. This exposed longer planar optical cane 22 is then etched as previously described and cut into individual planar optical waveguides. Alternatively, a plurality of master masks 24, shown in FIG. 14(b), each producing a distinct optical circuit pattern, 24a, 24b, and 24c, may be indexed into position over said longer planar optical cane 22 as said longer planar optical cane is moved into the exposing position. In this manner, one longer planar optical cane 22 may be used to produce several different types of integrated optical device. Yet another alternative method of forming the preselected refractive index profile, and one which is within the scope of the claimed invention is to etch precise dimensional grooves 10 in the unstretched substrate 1 which correspond to the preselected optical circuitry pattern and fill those grooves with materials 11 as shown in FIG. 10(a) using either soot deposition, sol-gel or slurry casting techniques. The refractive index of materials 11 is different from the refractive index of the substrate. A cross-connect layer 12 may be applied using soot deposition techniques previously described. The resulting structure is fused and stretched as above. The fused structure is etched, as above, as necessary to further define the preselected optical circuitry pattern. In particular, regions of cross-connect layer 12 may be removed, leaving cross-connect channel 13 as depicted in Fig. 10b. Another alternative is to etch precise dimensional grooves 14 in substrate 1 which correspond to the preselected optical circuitry shown in FIG. 11(a). Thereafter at least one shaped (e.g., circular, square, elliptical or D-shaped) optical fiber preform or large core optical fiber 15 (hereinafter optical fiber preform 15) with core regions 16, 16' having the desired refractive index profile (e.g., step or graded) is placed in at least one of grooves 14. The optical fiber preform may alternatively consist of a core only. In addition, stress inducing materials or members may be included to provide stress birefringence. In Fig. 11(a), optical fiber preform 15 has been ground to expose core region 16. Optical fiber preform 15 is placed on the substrate such that its optical axis is parallel to the stretch axis of the substrate. In an alternative method (not claimed herein), the optical fiber preform may be placed on a planar substrate without grooves, and overcoated. Alignment projections or alignment grooves may be included in the cane to assist in fiber positioning. The shape of the optical fiber preform is chosen based on the anticipated changes during stretching. For example, circular cores may be transformed into elliptical cores. The shape transformation may be controlled to some extent by limiting the soot thickness and also by using shaped blanks with stiff claddings. A cross-connect layer 17 of proper refractive index is placed over optical fiber preform 15 and fused as described previously. The cross-connect layer 17 may be in contact with the surface optical fiber preform 15 as shown in FIG. 11(a) or may be a predetermined distance above optical fiber preform 15 as shown in FIG. 11(b). A protective overclad layer 18 may be applied over the cross-connect layer 17 as shown in FIG. 11(c), using soot deposition, sol-gel or slurry casting techniques. This protective layer reduces the contamination and/or diffusion of the dopant material during consolidation. The resulting structure is fused as previously described. The fused structure is then stretched and etched as described above to further define the preselected optical circuitry pattern. Alignment grooves 25, as shown in FIG. 11(c), may be used to align the master mask precisely relative to the embedded canes or fibers for proper cross-connection. Alignment projections may be used instead of grooves 25. An example of a simple branching cross-connect is shown in FIG. 12 where the branching circuitry 19 is formed by etching the cross-connect layer 17 of FIG. 11(b) after the stretching operation to leave cross-connect circuit 19 between waveguide cores 16 and 16'. Another method of forming the cross-connect between waveguide conductors 46 and 46'embedded in the substrate is to etch cross-connect channels 20 as shown in FIG. 13. Thereafter, these channels are filled with materials 21 having refractive index suitable for the required optical inter-connection, using soot deposition, sol-gel or slurry casting techniques. In the embodiments of both Figs. 12 and 13, the waveguide conductors and cross-connect circuitry are overcoated with glass and form a solid waveguide structure. In yet another method (not claimed herein), planar optical canes (after stretching) including a core layer, or a core layer plus a predetermined thickness of cladding layer, are etched as indicated in Fig. 15 to provide cross-connect patterns in the core layer. The cross-connect patterns are raised approximately 8 microns from the surface of the substrate. Optical fibers with core 36 and cladding 37 are placed with core side contacting the raised cross-connect circuit 39. Sectional views of two such optical fibers along line A-A of Fig. 15 are provided in Figs. 16a and 16b. Alignment may be facilitated with alignment projections 35 formed in the cane. Alternatively, alignment grooves may be used to mate with corresponding projections in a fiber positioning means. The optical fibers are then held in place permanently with low index epoxy or plasma-enhanced CVD so that they rest on the raised cross-connect circuit. Thereafter, the cane and fiber assembly may be overcoated with glass by conventional means to form a solid waveguide structure with pigtails. By placing the optical fibers in the structure after the stretching operation, the fibers may be used as pigtails or for the attachment of pigtails by splicing. The present invention has been particularly shown and described with reference to the preferred embodiments thereof. However, it will be understood by those skilled in the art that various changes may be made in the form and details of these embodiments without departing from the scope of the invention as defined by the following claims. For example, although the invention has been described herein primarily with reference to single mode waveguide structures, it may also be applied to multimode waveguide structures, with appropriate changes to dopant levels and dimensions. | A process of manufacturing an elongate integrated optical device with at least one channel waveguide therein, comprising: (a) forming an elongate fused glass structure of substantially rectangular cross-section comprising a first glass (1) having a first refractive index; (b) removing material from at least one longitudinal portion of a surface of said elongate glass structure to form at least one longitudinally extending groove (10, 14) therein; (c) placing in said at least one groove, at least one second glass (11, 16, 16') having a second refractive index which is higher than said first refractive index so as to provide at least one channel waveguide in the device to be manufactured; and (d) heating and longitudinally stretching the resulting assembly to reduce the cross-section thereof, thereby resulting in said elongate integrated optical device with said at least one channel waveguide therein. The process of claim 1, wherein soot deposition techniques are used to place said at least one second glass (11) in said at least one groove (10). The process of claim 1, wherein said at least one second glass (16, 16') comprises at least one optical fiber preform (15). The process of claim 3, wherein said at least one optical fiber preform (15) comprises at least one large core optical fiber. The process of claim 3 or 4, wherein after said at least one optical fiber preform (15) is placed into said at least one slot, a cross-connect layer (12, 19) is applied thereupon. The process of claim 5, wherein portions of said cross-connect layer are removed to leave a crossconnect pattern. The process of any preceding claim, wherein the aspect ratio of said elongate fused structure is about 1:7. The process of any preceding claim, wherein the edges of said elongate fused structure are rounded to reduce geometric distortion during said heating and stretching step. The process of any preceding claim, wherein the reduction in cross-sectional dimensions during said heat and stretching step is within the range of 10:1 to 20:1. The process of any preceding claim, wherein said at least one second glass placed in said at least one groove is initially at least 100 µm thick and is reduced in thickness to approximately 6-8 µm during said heating and stretching step. The process of any preceding claim, wherein a lithographic technique is used for removing material. The process of any preceding claim, wherein a region of additional material (18) is applied to said assembly. The process of claim 12, wherein said step of applying a region of additional material comprises applying an overclad layer (18) by soot deposition or other chemical vapor deposition technique, said process further comprising the step of fusing said overclad layer, the composition of said overclad layer being chosen to avoid leaving voids after fusing. The process of any preceding claim, further comprising the step of transversally cutting said elongate integrated device into a plurality of portions. The process of any preceding claim, comprising placing at least one optical fiber in contact with a portion of said elongate integrated device in communication with optical circuitry therein. The process of claim 15, further comprising the creation of alignment means to assist in positioning said at least one optical fiber. The process of claim 15 or 16, further comprising overcoating with glass the assembly of said at least one optical fiber and said portion of said elongate integrated device. | CORNING INC; CORNING INCORPORATED | BHAGAVATULA VENKATA ADISESHAIA; BHAGAVATULA, VENKATA ADISESHAIAH; BHAGAVATULA, VENKATA ADISESHAIAH, CORNING INC. |
EP-0490108-B1 | 490,108 | EP | B1 | EN | 19,970,723 | 1,992 | 20,100,220 | new | G01T1 | G01T1 | G01T7, G01T1 | G01T 1/20, G01T 7/00 | Method, apparatus and applications of the quantitation of multiple gamma-photon producing isotopes with increased sensitivity | Prior art methods for quantitation of radioisotopically labeled molecules employ isotopes emitting a single electron, positron or gamma-photon. Their sensitivity is limited by background events which cannot be distinguished from the decays of the isotopic label. There are isotopes decaying with concurrent production of a positron and a gamma photon, with a subsequent positron-electron annihilation producing paired 511 keV gammas with opposite momenta. The Coincident Gamma-photon Detector (CGD) registers a count when coincident gamma-photons of known energies are detected. When set to the triple gamma signature of a particular isotope, the CGD achieves exceptional background rejection with resultant improved capacities to quantitate minute traces of the isotope. With the increased sensitivity thus achieved, there are advantageous novel uses of the multiple gamma producing isotopes, for the quantitation of molecules in which they can be incorporating or adducted to. | 1. Field of the invention.This invention relates to improvements in the art of quantitating radioisotopes whose decay culminates in a production of multiple gamma-photons, and the quantitation of molecules with these isotopes incorporated. The order of magnitude improvements result from an appropriate choice of isotopes and novel apparatus, a Coincident Gamma-photon Detector (CGD), which together achieve an excellent rejection of background radiation events. With the greatly reduced background counts there are advantageous usages of several isotopes which have not previously been utilized for molecular quantitations. 2. Prior ArtThe following patents and application describe various known apparatus and methods of detection of radiation. Name Date Number Kalish3-16-76USP 3,944,832 Wilkinson5-4-76USP 3,954,739 Blumberg et al2-19-80USP 4,189,464 Kaul et al11-25-80USP 4,235,864 Nickles12-23-86USP 4,631,410 Mullani2-10-87USP 4,642,464 Wong3-3-87USP 4,647,779 Curtiss et al6-30-87USP 4,677,057 Karcher et al6-14-88USP 4,751,389 Ginsberg et al4-11-89USP 4,802,505 East German (Abstract)241,788-A Radioisotopes are detected through the absorption of the energies of decay products. Scintillators are often used to convert the energy of the emitted particle into a burst of low energy photons, which are collected by photodetectors. More specifically low cost organic scintillators (plastic or liquid) are used in prior-art instruments. Their advantages are low cost, a capacity to use complex shapes and fast timing. The major disadvantages excluding their use in the CGD are low gamma stopping power and mediocre energy resolution. Signal amplification and analysis commonly precede the final registration of a decay count. The sources of background radiation which trigger radiation counters include cosmic rays, radon gas and the traces of man-made and natural radioisotopes contaminating many materials used in radiation counters. Highest in the latter category are carbon-14 and potassium-40. The background of registered counts without a sample present sets a minimum for the amount of radioisotope which can be detected or must be utilized to achieve a valid quantitative assay. There must be enough sample radioactivity to achieve a statistically significant sample count rate over that of the background count. The backgrounds registered by current commercial instruments are in the range of 15-60 counts per minute. The sensitivity of an assay is thus improved by any measures which reduce background counts. With increased sensitivity shorter counting times and/or reduced amounts of a sample will suffice for a radioisotopic assays. There will be corresponding increases in sample throughput, decreased radiation hazards and less radioactive waste to dispose of. There is considerable prior art for the reduction of system background counts. Shielding the sample chamber and critical detector components from exterior radiation is a common measure. Very pure shielding materials are used to minimize their contribution of contaminating radioisotopes. Parameters of detection systems can be set to reject background events falling outside of the energy window(s) characteristic of the emissions of a known isotope. For example gamma emitting isotopes have nuclei which drop to a lower angular momentum state(s) with emission of a mono-energetic gamma-photon. In a typical gamma counter, the scintillator converts the gamma to a burst of lower energy photons which are absorbed by a photodetector and the energy quantitated with associated electronics. Energy depositions outside of the energy window of the isotope's gamma are not counted. To recognize background due to cosmic rays, a detector external to the sample chamber shield can be used in conjunction with the sample chamber's instruments. The external veto counter rejects a coincident count from the sample chamber. Using these prior-art techniques a very low background apparatus has been constructed which reduces backgrounds to a few counts per hour. To achieve backgrounds of a few counts per day, the detectors are placed deep underground. The state of the art in ultra-low background counting is represented for example in reports of R.L. Brodzinski et al.. NIM A239, (1985) 207. and R.L. Brodzinski et al., Further reduction of radioactive backgrounds in ultrasensitive germanium spectrometers, NIM, in press. Only three such instruments now exist worldwide because the system costs more than $1,000,000. They are far too costly for routine molecular quantitation tasks. Moreover they are not optimized for particular isotopes and are not designed for the high throughput needs of the chemical, biological of commercial diagnostic laboratories. 3. Invention DevelopmentIn the development of this invention, information was gathered with one of the ultra-low background systems. A particular interest was the background intrinsic to body fluids. Assaying biological macromolecules is a projected major area of application of this invention. With a 50 ml blood sample, it was observed with the gamma counting instrumentation that: a) the background increases rapidly for low energies, E ≤ 300 keV (kilo electron volts), with indications of a few discrete lines with count rates of a few hundred counts per hour; b) the background is a few counts per hour in the range 300 ≤ E ≤ 500 keV; c) there is a 511 keV peak of a few tens of counts per hour, attributable to positrons in the sample producing 511 keV annihilation gamma pairs; d) the background in the range 600 ≤ E ≤ 1000 keV was below a count per hour. e) there is a background attributable to potassium-40 with count rates of the order of 100 counts per hour. Background can be rejected by the use of time coincidence methods, as achieved for example in prior-art uses of positron emitting isotopes. This decay signature is used in the rejection of single gamma background events, as employed for example in positron emission tomography. However, the evident presence in blood of significant traces of positron emitting isotopes set an undesirable high background for rejections employing only double coincidence. Advantage can be taken of the existence of isotopes with more complex decay signatures. There are isotopes which decay with the concurrent production of more than two gamma-photons. Among them there is a substantial sub-family which initiate decay through the emission of a positron and leave the nucleus in an excited angular momentum state, leading to prompt gamma emission. This solitary gamma plus the two annihilation photons (E = 511 keV) derived from a positron-electron interaction yields a triple of coincident gammas with known energies. Thus the net decay signature is a production of the back-to-back 511 keV gamma pair and a solitary gamma with a non-correlated emission direction and distinct energy (for some of the isotopes the solitary gammas can have a few different energies). The average delay between the appearance of the annihilation pair and the solitary gamma generally is much less than 100 nsec (nanoseconds). Typically it is about 0.1 nsec within liquids or solids and 10-100 nsec in air at one atmosphere of pressure. For brevity, members of this family will be termed triple gamma isotopes. As chemical reagents they include carbon, nitrogen, oxygen, fluorine, bromine and iodine. The chemistry of iodine is particularly useful. Through simple adduction at double covalent bonds such as >C=C< and -N=C<, iodine is used to radioisotopically label preformed macromolecules including ribonucleic acids, deoxyribonucleic acids, carbohydrates and proteins. The single-gamma-emitters iodine-125 and iodine-131 are extensively utilized to label antibodies and/or antigens for the radioimmunoassay (RIA) procedures of biomedical research and medical diagnostics. Immunoassays utilize the exquisite binding specificities of antibodies to quantitate either antigens or antibodies, and the quantitations can proceed in complex body fluids or on tissue samples. RIA is the most sensitive of the immunoassay techniques. Methodologies are well described in: A.E. Botton, W.H. Hunter, Radioimmunoassay and related methods, page 26.1-26.55 in the Handbook of Experimental Immunology, ed. L.A. Herzenberg et al., publisher Blackwell Scientific, 1984 and D. Freifelder. Physical Biochemistry . chpt. 10, publisher W.H. Freeman, 1977, D. Bereitag, K.H. Voigt. in Treatise on Analytical Chemistry, Part I, p. 285-333, publisher J. Wiley & Sons. Triple gamma emitting isotopes have not been previously utilized for RIA procedures, and more generally, for sensitive quantitations of molecules. The sources of background affecting the quantitation of triple gamma isotopes was explored with pilot instrumentation. A three detector assembly was used. Each detector had a NaI(Tl) scintillator coupled to two inch photodetectors, Ortec preamplifiers and spectroscopy preamplifiers,appropriate signal delay lines and a high voltage power supply. No external shielding was employed. One detector served as a master to initiate a coincidence interval of 50 nsec. Three coincidence counting modes were implemented: (1) to count all events registered by the master; (2) to count a master event if accompanied by a coincident event in another counter; and to count a master event if accompanied by coincident events in the two other detectors. In this third mode, two of the energy windows were 511±50 keV. The energy spectrum was measured for each coincidence mode using multichannel analyzers. For the experiment of Figure 1a the 50 ml liquid sample was blood. This trial represents a worst case bioassay situation because of the presence of the single-gamma-emitting potassium-40 in biological fluids and tissues. A major projected use of the invention is the sensitive quantitation of biological macromolecules in the presence of body fluids. With no coincidence requirement the energy spectrum reflects the background, dominated by potassium-40 gammas and their lower energy Compton scattering events. With the double coincidence requirement, the background count is reduced about 100 fold. These counts are attributed predominantly to traces of positron emitting isotopes. The triple coincidence mode corresponds to a selective acceptance condition for triple gamma producing isotopes. The accepted count is decreased about another 50 fold, as compared to the dual coincidence mode. The peak at 1550 keV is attributed to 510 keV gammas from ubiquitous radon gas which are accidently coincident with annihilation gamma pairs derived from traces of positron emitting isotopes, as 510 + 2 x 511=1532 keV. This peak doubled in height when air with its radon replaced 50 ml of blood or urine during acquisition of a triple coincidence spectrum, as shown in Figure 1b. With the air sample an increasing background towards lower energies is attributed to Compton scattered gammas, which contribute to accidental gamma triples arriving within the 50 nsec coincident interval. This contribution is quenched by the presence of more absorbing blood or urine. This proof of concept experiment illustrates that excellent background rejection can be achieved with a CGD, when only events indistinguishable from a triple gamma signature are counted. These results and those obtained with the ultra-low background system guided design of this invention. The experimental results also guide choices of triple gamma isotopes most suitable for radioisotopic labeling of molecules. Preferably, the solitary gamma should have an energy distinguishable from the 510 keV radon-222 gamma, so that the gamma background from radon can be most effectively rejected. Furthermore, the energy spectrum from blood obtained with the ultra-low background counter recommends an energy greater than 300 keV and preferably in the 600-1000 keV range. A survey of over 1000 known isotopes was made for triple gamma isotopes which satisfied the above criteria. Also a halflife of at a least a few hours is desirable to accommodate production, radioisotopic labeling chemistries and distribution to users. Several suitable isotopes are thus available: Isotope halflife E in meV of solitary gamma(s) selenium-1377.1 hours1.31, 0.86 bromine-7617 hours1.21, 0.75, 0.33 germanium-6940 hours0.576 bromine-7757 hours0.813, 0.520, 0.237 iodine-1244.2 days0.72, 0.6 iodine-12613 days0.64, 0.395 The iodine isotopes with their longer halflives and simple adduction chemistries are particularly well suited for use as radioisotopic labels for other molecules. The preferred embodiment of the CGD is optimized for iodine-124 quantitation. Among the bromine and iodine isotopes the best background rejection can be achieved with the highest energy E = 0.72 keV gamma of iodine-124. The preferred embodiment of the CGD is optimized to the needs of the RIA with iodine isotopes. Quantitations will be feasible much below the level of the backgrounds of contemporary assay systems. Thus diagnostic detections of antigens (such as cancer or HIV virus indicators) will be much more sensitive. More generally assays of the molecules incorporating the triple gamma isotopes can be performed with much higher sensitivity. At least a thousand fold reduction in the minimal amount of radioisotope necessary for an assay will be achievable with CGD instruments, and corresponds to less than a nanocurie of triple gamma isotope. The corresponding amount of radiation is less than that from radioactive contaminants of television screens or the drinking water in areas of the Rocky Mountains. There is a novel application area. With the minimal necessary quantity of triple gamma isotope for assays performed in body fluids, the amount of energy deposited by a triple gamma isotope is much less than that of the resident radioisotopes, primarily potassium-40. Thus when desirable certain biochemical reaction component of an assay could be performed within the body, with an insignificant added radiological burden to the organism/patient. Subsequently the appropriately mounted sample would be withdrawn for radioisotopic quantitation in a CGD. For a single example, an antibody for the AID (or HIV) virus would be coupled to the surface of a flexible, thin plastic rod or ribbon. The binding of its conjugate iodine-126 labeled viral antigen would prepare the rod with its antibody-antigen complex for a displacement assay. When inserted into a blood vessel or body cavity, the disassociation of the iodine-126-antigen from the antibody would be accelerated, by the presence of homologous antigen competing for the two binding sites of each antibody. After a chosen interval, the plastic would be withdrawn and its retained iodine-126 antibody quantitated in a CGD. From the retention, time in body fluid and calibration parameters, the concentration of the viral antigen in the body fluid would be calculated. The great value in such insitu assays would be avoidance of numerous artifacts which can accompany removal of biological specimens from their natural environment. It is evident that quantitations utilizing a CGD are entirely distinct from usages of positron emitting isotopes in the imaging applications of Positron Emission Tomography (PET). A CGD will be a compact instrument, accommodate micro-samples, and be suitable for isotopes with long half lives. PET systems occupy a few rooms, are designed to accommodate people and require very short lived isotopes. A CGD assay will require about a nanocurie of isotope while PET imaging runs require tens of millicuries of isotope. The CGD uses only several scintillators while PET requires hundreds. The difference in the channels of required electronics leads to different technological challenges and design trade offs. SUMMARY OF THE INVENTIONThe method of the invention is the improved quantitation of isotopes decaying with concurrent emission of a positron and a gamma-photon, which culminates in the production of three gammas of known energy with two being a gamma pair resulting from positron-electron annihilation. The improvement results from the rejection of background events which are distinguishable from the decay signature of the known triple gamma isotope in the sample, with a concomitant capacity to achieve more sensitive quantitations of the isotope. This method was made possible by the results described above in Invention Development which provide the background spectra of blood, urine and air without added radioisotopes. The knowledge of the background spectrum permits the choice of the triple gamma isotope(s) which both: (1) satisfy practical requirements of the radioisotopic labeling and (2) has a suitably distinguishing decay signature. A candidate decay of the known isotope is counted only if the instrument of the invention cannot distinguish the event from a triple gamma decay as determined by each of the three following criteria: 1. There is coincident activation of three gamma detectors within an interval compatible with the known temporal statistics of the isotopic decay: typically an interval of about 10 nanoseconds and generally much less than 100 nanoseconds; 2. The gamma energies are compatible with those of the sample's isotope comprising two 511 keV annihilation gammas and that of the solitary gamma(s) emitting during the transition in angular momentum state of the daughter nucleus; 3. The angular distribution of the three candidate gammas is compatible with that of an opposed 511 keV annihilation pair, and the third directionally-noncorrelated gamma. This third criterion serves in the rejection of background events which could be initiated by cosmic ray collisions, independent decays of two contaminating radioisotopes and other complex background events. This criterion will cause undesired rejection of a triple gamma isotope decay, when the solitary gamma and one of the annihilation gamma pair activate the same detector. It is more desirable however to achieve the sought background rejection. The triple gamma isotope count losses can be calculated from the known geometry of the apparatus and suitable calibration experiments. The apparatus of the invention implementing the comparison of candidate events and the signature of a known triple gamma isotope is a Coincident Gamma-photon Detector (CGD) with the following general features: a sample containment transparent to the decay gammas, three or more gamma detectors well shielded from one another and intercepting gammas from the sample containment; the fast electronics including means for timing and pulse height analysis; exterior shielding; and a flow of radioisotope depleted gas serving to minimize airborne traces of contaminating radioisotopes. Automated systems of sample transport serving a CGD are prior art. With the improved background rejection achieved through the combination of method and apparatus, the triple gamma isotopes can be advantageously used as labels for the sensitive quantitation of radioisotopically labeled molecules. Triple gamma isotopes have not previously been utilized for this role. The applications of the invention thus include the quantitations of molecules labeled with multiple gamma isotopes, when background count rejection is accomplished by application of the three above specified criteria. The chemical methods of sample preparation are prior art. The invention is also useful for quantitations of other isotopes decaying with production of multiple gammas of known energy, i.e. positron emitters and isotopes whose nuclei can rapidly transit through several angular momentum states with accompanying production of gamma-photons. The efficacy of background rejection in these cases is dependent both on the isotope and the environment provided by the containing sample. These features and advantages of the invention will be further apparent from the following description of the preferred embodiments thereof, which are provided herein for the purpose of disclosure and should be taken in conjunction with the accompanying drawings. It should be understood that various changes and modifications of the preferred embodiments described herein will be apparent to those skilled in the art. BRIEF DESCRIPTION OF THE DRAWINGSFigure 1a is a plot of accepted counts versus total energy of the radiation with 50 ml of normal blood measured in the sample chamber, under event acceptance conditions of: Δ - no coincidence; o - double coincidence; and x - triple coincidence. Figure 1b is a plot with triple coincidence with: □---□ air; o---o normal blood; and x - normal urine. Figure 2 is a diagram of signal flow in the gamma detectors. Figure 3a is a vertical cross section of a typical detector assembly which is a preferred embodiment of the invention having four detectors. Figure 3b is horizontal cross section along line 2-2 of the detector assembly shown in Figure 3a. Figure 4 is an enlarged vertical cross section of a detector subassembly. Figure 5 is a cross-section of a detector subassembly consisting of scintillator, photomultiplier, photomultiplier bases and preamplifier. Figure 6 is a cross-sectional view of another photodetector mounting modification. Figure 7 is a side vertical view of the preferred embodiment of the photodetector mounting used in the gamma detector. Figure 8 is a schematic circuit diagram of the fast electronic and data acquisition circuitry. Figure 9 is a schematic circuit diagram of the electronics realizing a simplified energy discrimination using multiple, adjustable single channel analyzers (SCA). Figure 10 is a horizontal cross section of the passive/active external radiation shield. DETAILED DESCRIPTION OF THE COINCIDENT GAMMA-PHOTON DETECTORAll components of the apparatus are prepared from highly purified materials, so as to minimize gamma producing contaminants. In the Figure 2 schematic of the low background gamma detector assembly the gammas are absorbed by well-type multicrystals 1, wherein the electronic signal is amplified by low noise preamplifiers 2. The signals are further amplified by shaping amplifiers 3 which are also used as summators. The pulse height analyzers 4, e.g. analogue-to-digital converters (ADCs) and coincidence circuitry 5 are connected via Programmable Logic Analyzer (PLA) 6 to the appropriate microprocessor 7. The Figures 3a and 3b of the detector chamber illustrate for purposes of clarity cross sections as being of square and elongated shape and having four detectors which is preferable in the practice of the invention. The device could also be of parallelpiped, cylindrical or round construction with a minimum of three equally spaced and separated detectors. In the preferred embodiment each of four scintillators 10 is coupled through two solid state photodetectors 12 to low noise preamplifiers 13. The radioactive sample is in a container 8 made from low atomic number materials. Container 8 is sealed to prevent radioactive dust from contaminating the detector interior. The container is suspended on very high purity, quartz rod 14. The entire assembly is purged from a bottom vent with clean helium gas to eliminate radon and radioactive dusts prior to initiation of counting. The small aperture for sample insertion is blocked by a plug 15 after purging. The sample is positioned within a cylindrical low atomic number metal, e.g. aluminum foil 9. This foil can be simply replaced when an increasing background count indicates contamination. The positrons are predominantly annihilated within the sample and volume circumscribed by the cylinder. Count losses which would often accompany positron annihilation on a scintillator are thus avoided. Due to the low atomic number of the said container and the said foil shield, they are transparent to the gammas of energy less than 300 keV. The gammas are absorbed in the scintillation crystals producing photoelectrons and a resultant low energy photon shower. As shown in the cross sectional view of Figure 3b, there are the high density septa 12A are between crystals, to minimize back-scatter of photoelectrons and photons between detectors. The septa have a density preferably greater than 5 g/cc, such as obtained with bismuth, lead, thallium, mercury, gold, copper, tungsten, tantalum, and the like and alloys thereof. The entire detector subassembly is shielded from external radiation by a low radioactive background passive shield 11, constructed to serve as both Faraday cage blocking external electromagnetic pulse noise and external radiation (electrons/photons/neutrons) shield. In the schematic view of Figure 4 a scintillator 16 is covered by diffusively reflecting thin layer 17 and coupled to a photomultiplier 18. This reflecting layer limits losses of low energy photons from the photodetector assembly. The photomultiplier base 19 and the low noise fast preamplifier are also present. The photodetectors are optically coupled to the scintillators and are preferably narrow gap photodetectors such as mercuric iodide, high purity germanium, and the like. The photomultiplier base 19 and the low noise, fast preamplifier 20 are also presented. In another implementation solid state photodetectors are used, i.e. the scintillators are optically coupled to preferably narrow gap semiconducting photodetectors made of silicon, mercuric iodide, high purity germanium, and the like. The scintillator 16 preferably has a density greater than 4 g/cc and an atomic number greater than 50. Illustrative, but not limiting, are scintillators of bismuth germinate, gadolinium orthosilicates, barium fluoride, cesium iodide, or sodium iodide. Particularly preferred are scintillators with a density greater than 10 g/cc. These particular choices of system components provide some optimization of the system for quantitation of iodine-124 and iodine-126. In Figures 5-7, there are illustrated various mounting techniques for the fabrication of the photodetectors/scintillator. In Figures 5 and 6, the scintillator 22 is mounted to a single solid state photodetector 21 using a fan-shaped optically transparent coupling 23. The side of the assembly which is not adjacent to the solid state photodetector 21 is suitably coated with a diffusing/reflecting layer 24. The dashed line represents in Figure 5 the division between the non-glass coupler 23 and the scintillator crystal 22, whereas in Figure 6 there is no dash separation line shown, as the scintillator 26 is formed and shaped to provide the desired truncated effect to the end mounts for these particular photodetector/scintillators. With reference now to Figure 7, there is shown another alternate construction which is of the preferred arrangement wherein two solid state photodetectors 28 are joined and connected to the scintillator 29 having tapered ends (like those shown in Figure 6. In a like manner, said scintillator 29 is further provided with a diffusive reflector 30. In Figure 8 there is shown a schematic circuit diagram of the multichannel electronics and data acquisition circuitry. The signal from the scintillating detector 31 is amplified by a fast preamplifier 32 and shaped by a shaping amplifier 33. The pulse amplitude is then analyzed by a pulse height analyzer 34 and triggers a NIM (or TTL) level pulse in a fast threshold device (single-shot) 35. The output from four single shots is feeding coincidence circuitry 36. All pulse high analyzers 34 and coincidence circuit 36 are communicating with a dedicated microprocessor 37 via eight bites bus line 38. For simplicity only two channels of electronics are depicted whereas in the real device three or more channels will be used. Referring to Figure 8, there is shown four scintillation detectors 31 each corresponding to a respective electronics channel, although more or fewer detectors 31 may be implemented in which case a corresponding number of channels will exist. The detectors 31 detect ionizing radiation and output electrical signals. Since the signals output by the detectors 31 are typically low-level signals, they are received by low-noise preamplifiers 32, generally two preamplifiers 32, per channel, which amplify the low-level signals without appreciably degrading the signal-to-noise ratio of the low-level signals. The signals developed by the preamplifiers 32 are received by amplifiers 33, generally one amplifier 33 per channel, which add, amplify and appropriately shape the signals for output to a pulse height analyzer 34. The pulse height analyzer 34 analyzes the signal output by the amplifier 33 to determine the number of occurrences of pulses that fall within a specified amplitude range and outputs a signal to coincidence circuitry 35. Preferably, three single channel pulse height analyzers can be employed for each channel rather than a single pulse height analyzer 34 for all channels. Thus, a total of twelve single channel pulse height analyzers are used in this alternate embodiment device. In such a case, each single channel pulse height analyzer analyzes the amplified and shaped signal output of its respective amplifier 33 to determine the number of occurrences of pulses that fall within its respective specified amplitude range. The coincidence circuitry 35 outputs a pulse to a Programmable Logic Analyzer 36 when it receives a specified number of appropriate pulses within an assigned time interval from the pulse height analyzer 34. The Programmable Logic Analyzer 36 analyzes the pulses received from the coincidence circuitry 35 and outputs a signal appropriate for processing by a microprocessor 37. The micro-processor 37 receives the signal from the Programmable Logic Analyzer 36, processes the signal and determines whether to register the analyzed event as a valid count. Figure 8 is a block diagram of the electronic circuitry of the present invention which is conventional in design and construction, a more detailed description is deemed unnecessary. In this regard, it should also be understood that other circuit designs may be employed by skilled artisans in lieu of the circuit design shown herein without departing from the scope of the present invention. In Figure 9 an alternate circuit design is shown having an additional detector with a corresponding preamplifier, amplifier and single channel pulse height analyzer operated in a threshold mode. This detector-analyzer arrangement is mounted externally of the passive shield and outputs a pulse/signal to the programmable logic analyzer which is used to reject background radiation, such as cosmic Rays. Thus, instead of using (three or more) costly, high resolution pulse height analyzers, the Programmable Logic Analyzer 46 analyzes the coincidence and value of the output of twelve (much less expensive) single channel pulse height analyzers, and the anticoincidence of the thirteen single pulse height channel analyzer, and then, if desired, may update the count rate of a suitable counter (now shown in Figure 10) connected to the Programmable Logic Analyzer. Thus, both the coincidence and energy analysis for three of the four counters, and the anticoincidence analysis with input from an external shield detector, are implemented more simply and economically. In Figure 9 there is shown a schematic circuit diagram of the preferred embodiment of the multichannel electronics and data acquisition circuitry, specifically set to detect the iodine-126. The signal from the scintillating detector 39 is amplified by a fast preamplifier 40 and shaped by a shaping amplifier 41. It is then split and looked upon by three single channel analyzers (SCA1, SCA2 and SCA3). The SCAl 42 is set for energy of 511 keV ± 10%. SCA2 43 is set for an energy of 600 keV ± 10% and SCA3 44 is set for 1.1 meV ± 10%. If the detected energy is within the SCA range, a short duration TTL level pulse is generated. Thus the output from four scintillation counters is processed by twelve SCA and then analyzed by a Programmable Logic Analyzer (PLA) 46. Optionally, the output of the plastic scintillator 45 is appropriately amplified/shaped and is analyzed by SCA 47 operated in the threshold mode and can be used to reject cosmic rays. Thus, the PLA looks into a coincidence and value of output of twelve SCAs and anticoincidence of thirteen SCAs and then updates the count-rate at counter 48. In Figure 10, there is shown an optional shielding arrangement which may be employed in the practice of the invention. As shown therein, a scintillation counter assembly 49 formed in the same manner as those hereinbefore described, such as shown in Figures 1-6, and said assembly; is disposed inside a plastic anticoincidence scintillator 50. Very high purity oxygen free copper (OFHC) is used as an internal part of passive shield 51 and operates to stop all photons with E ≤ 100 keV, including K-edge photons from lead. A further thick ring of high purity lead 52 stops the majority of high energy photons (E ≤ 100 keV) as well as all charged particles with E ≤ 10 meV. Lastly, an external ring of boron loaded plastic 53 is used to stop the majority of low energy neutrons. Although a cylindrical shape is shown, other geometrical shapes may be employed for construction of the device, such as cylindrical, square or rectangular, parallelpiped, and the like. Accordingly, the present invention as described and shown herein, is adapted to fulfill the objects and attain the ends, results and advantages described as well as those inherent therein. However, it should be apparent that other modifications and changes in the details of construction and arrangement of parts may be made as readily suggested to those skilled in the art, all without departing from the scope of the claims attached hereto and forming a part of this application. | A method of quantitating a sample of a known radioisotope decaying with production of multiple gamma-photons, wherein a radioisotope having a complex decay signature such as a triple gamma decay signature is used, and wherein background rejection is achieved by characterizing candidate decay events with several and at least three gamma detectors (10, 16, 22, 29) and by rejecting candidate events distinguished from those of the said radioisotope through failure of at least one of the following criteria: a. the coincident detection of the candidate gamma-photons; b. having the detected energies and total energy deposition attributable to the said isotope; c. having an angular distribution of energies in detectors attributable to said gamma-photons of the said isotope. The method of claim 1, wherein the scintillator (10, 16, 22, 29) of each gamma detector has a density greater than 4 g/cc and is of material with an atomic number greater than 50, and wherein the scintillators are preferably chosen from the group consisting of bismuth germanate, gadolinium orthosilicate, cesium iodide, barium fluoride, and sodium iodide. The method of claim 1 or claim 2, wherein at least three photodetectors (12, 18, 21, 25, 28) are optically coupled (23) to the said three scintillators (10, 16, 22, 29), and wherein the photodetectors (12, 18, 21, 25, 28) are preferably selected from the group consisting of photomultipliers or semiconducting photodetectors based on silicon, mercuric iodide and germanium, and/or wherein the photodetectors are mechanically separated and shielded from each other by a material (12A) with a density greater than 5 g/cc, said separating material being preferably selected from the group consisting of bismuth, lead, thallium, mercury, gold, copper, tungsten, tantalum, and mixtures and alloys thereof. The method of any one of the preceding claims, wherein the radioisotope is selected from the group consisting of emitters of: a. a positron and a gamma-photon concurrently, b. positrons detectable by annihilation photons, and c. multiple gamma-photons concurrently. The method of claim 4, wherein the radioisotope is iodine-124 or iodine-126, or wherein the radioisotope is selected from the group consisting of germanium-69, selenium-73, bromine-76 and bromine-77. The method of any preceding claim, wherein molecules to be quantitated are covalently or non-covalently coupled to the said radioisotopes, and wherein the said molecules preferably comprise proteins, carbohydrates, ribonucleic acids or deoxyribonucleic acids, and/or wherein the radioisotopically labelled molecules are reagents for radioimmunoassay systems. An apparatus for carrying out the method of any one of the preceding claims for quantitating a sample of a known radioisotope decaying with the production of multiple gamma-photons, the apparatus comprising a central sample (8) surrounded by an inner protective foil shield (9) of an atomic number below 13, which in turn is surrounded by several and at least three crystal scintillators (10, 16, 22, 29), said scintillators being separated on each side by material (12A) with a density greater than 5 g/cc, said scintillators (10, 16, 22, 29) having directly mounted on at least one end a photodetector (12, 18, 21, 25, 28), and wherein the at least three scintillators mounted with photodetectors are surrounded by a continuous shield (11, 51, 52, 53) against external radiation, said shield having a removable plug (15) for insertion or withdrawal of the central container (8) containing the sample and vents for purging gases. The apparatus according to claim 7, wherein the septa material (12A) is selected form the group consisting of bismuth, lead, thallium, mercury, gold, copper, tungsten, tantalum, and mixtures and alloys thereof, and/or wherein the scintillators (10, 16, 22, 29) have a density greater than 4 g/cc and are of material with an atomic number greater than 50, and/or wherein the scintillators (10, 16, 22, 29) are chosen from the group consisting of bismuth germanate, gadolinium orthosilicate, cesium iodide, barium fluoride, and sodium iodide. The apparatus of claim 7 or claim 8, wherein the at least three photodetectors (12, 18, 21, 25, 28) are optically coupled (23) to at least three separate scintillators (10, 16, 22, 29) and are of the semiconducting type, and/or wherein the photodetectors (12, 18, 21, 25, 28) are selected from the group consisting of mercuric iodide and germanium, and/or wherein said photodetectors (12, 18, 28) are mounted on both ends of each of said at least three scintillators (10, 16, 29), said photodetectors preferably being coupled to low noise preamplifiers (13, 32). The apparatus of any one of the claims 7 to 9, wherein said crystal scintillators (16, 22, 26, 29) are covered by a diffusively reflecting material (17, 24, 27, 30) except at the surface adjoining the photodetectors (18, 21, 25, 28), and/or wherein the ends of said crystal scintillators (10, 16, 29) are elongated and tapered at opposite ends thereof. The apparatus according to claim 9, including electronic circuitry means having a shaping amplifier/summator (33, 41) connected to the preamplifiers (31, 40) and to at least one high resolution pulse height analyzer (34, 42, 43, 44), and coincidence means (36) coupled to said at least one pulse height analyzer (34) and a programmable logic analyzer (36, 46) which in turn is the input to a microprocessor (37), and/or wherein for each of said four scintillators (10, 16, 22, 29) and shaping amplifiers/summators (33), there are three single channel analyzers set for predetermined energy levels of 511 keV, 600 keV and 1.1 meV within windows of ± 10 % providing for optimal quantitation of iodine-124, wherein said at least one pulse height analyzer (34) is preferably operated in a threshold mode so as to reject background radiation, wherein a plurality of shields (51, 52, 53) are optionally disposed around said test sample, and at least one (52) being of high purity lead or lead alloy, and another (53) comprising a boron loaded plastic, a further high purity copper shield (51) being optionally disposed between said high purity lead shield (52) and said scintillators (10, 16, 22, 29), the apparatus optionally further comprising an arrangement in which a detector (45) serving as an active shield is placed between high purity copper/lead shield (51, 52) and the boron loaded plastic (53), the said active shield preferably being a photodetector with a plastic scintillator. | BIOTRACES INC; BIOTRACES, INC. | ELBAUM DANEK DR; ELBAUM, DANEK DR. |
EP-0490122-B1 | 490,122 | EP | B1 | EN | 19,950,222 | 1,992 | 20,100,220 | new | B23B51 | B23B51 | B23B27, B23B51 | B23B 27/14B, B23B 51/04C | Drill with replaceable cutting inserts | A metal cutting drill (10) with two replaceable cutting inserts (30, 31) which are positioned to cut the full circumference of a hole during each one-half revolution of the drill (10). Each insert is triangular and includes an active cutting edge having a curved corner to enable the insert (30, 31) to cut near the center of the hole. Each insert (30, 31) may be inverted and indexed in order to bring an alternatively usable cutting edge into active cutting position. By virtue of the inserts (30, 31) being triangular, the curved corners on the cutting edges of the two inserts (30, 31) may be positioned relatively close together and yet sufficient space is left between the inserts (30, 31) to enable the drill body (13) to be relatively thick and strong. | This invention relates to a drill with replaceable cutting inserts for forming holes in metal workpieces and, more particularly, to a drill having cutting inserts which may be easily removed and replaced after the cutting edges become worn. A drill with a pair of indexable cutting inserts is disclosed in United States Patent 3,963,365. In that drill, one insert is an outer insert which removes metal from the peripheral wall of the hole and inwardly toward the center of the hole in a cutting arc whose width is equal to one-half the radius of the hole. The other insert is an inner insert which removes metal from the center of the hole and outwardly toward the peripheral wall of the hole in a cutting arc of substantially equal width. While drills of the type disclosed in the US Patent 3,963,365 have enjoyed significant commercial success, the axial feed rate of such a drill is relatively slow due to the fact that a full revolution of the drill is required to cut the full circumference of the hole. United States Patent 4,373,839 discloses a drill which may be fed axially at a rate approximately twice that of the US Patent 3,963,365 drill. This is because the two cutting blades of the US Patent 4,373,839 drill are positioned so as to cut the entire circumference of the hole during each one-half revolution of the drill. A small diameter core is left between the two blades at the center of the hole but the core is twisted off as the depth of penetration of the drill increases. Certain embodiments of the drill disclosed in the US Patent 4,373,839 utilize indexable cutting inserts having multiple cutting edges which may be alternately used when a given edge becomes worn. To the best of applicant's knowledge, drills of this type with indexable cutting inserts have never been marketed commercially. Inserts of the type disclosed in the patent are located so close together along their sides that the portion of the drill body between the inserts cannot be made sufficiently strong to withstand the heavy cutting forces which are imposed on the body by way of the inserts during high speed drilling. The object of the present invention is to provide a new and improved drill with replaceable cutting inserts of the same general type as disclosed in the US Patent 4,373,839, said drill being able to withstand heavy cuttings forces while enjoying the benefits of replaceable cutting inserts. In order to achieve this objective, the present invention provides a drill in accordance with claim 1. An advantage of the invention is to achieve the foregoing through the provision of a drill having triangular inserts with uniquely curved cutting edges and with steeply inclined sides which enable the corners of the inserts to be positioned closely adjacent one another while leaving a strong section of drill body between the sides of the inserts. Another advantage resides in the provision of a novel triangular insert having alternately usable cutting edges each formed with a convexly curved corner position. These and other characteristic features and advantages of the invention will become more apparent from the following detailed description of a prefered embodiment with reference to the accompanying drawings, wherein : FIGURE 1 is a perspective view of a new and improved drill incorporating the unique features of the present invention. FIGURE 1A is an enlarged fragmentary perspective view of the tip end portion of the drill illustrated in FIGURE 1 but showing the drill with one of the inserts removed. FIGURE 2 is an enlarged fragmentary side elevational view of the drill illustrated in FIGURE 1 and shows the drill forming a hole in a workpiece. FIGURE 3 is an enlarged end view of the drill. FIGURE 4 is a perspective view of one of the triangular inserts. FIGURE 5 is a top plan view of the insert. FIGURE 6 is a front elevational view of the insert. FIGURE 7 is an edge view of the insert as seen from the right of FIGURE 6. FIGURE 8 is an enlarged schematic view showing the inserts drilling a hole. As shown in the drawings for purposes of illustration, the invention is embodied in a drill 10 for forming a cylindrical hole 11 (FIGURES 2 and 8) in a workpiece 12 made of iron, steel or other metal. The drill comprises an elongated and generally cylindrical body 13 made of high carbon steel and having a tip end 14 and an opposite shank end 15. The shank end of the body is adapted to be clamped in a power-rotated holder (not shown) for effecting rotation of the drill about its own axis A (FIGURE 3), the rotation herein being in a counterclockwise direction as viewed in FIGURES 1 and 3. It will be appreciated that the drill could be held rotationally stationary and that the workpiece could be rotated about the axis of the drill. Two generally diametrically spaced flutes 16 and 17 are formed in the body and, in this particular instance, extend helically around and along the body from the tip end 14 toward the shank end 15 to enable metal chips to escape from the hole 11. Each flute is generally V-shaped in radial cross-section and is defined by a pair of walls 18 and 19. The wall 18 of each flute faces generally in the direction of rotation while the wall 19 faces generally opposite to the direction of rotation. Generally diametrically spaced pockets 20 and 21 (FIGURES 1A and 3) are formed in the body 13 adjacent the tip end portions of the flutes 16 and 17, respectively, each pocket being formed near the wall 18 of the respective flute. Replaceable cutting inserts 30 and 31 are seated in the pockets 20 and 21, respectively, and act to cut the hole 11 in the workpiece 12 when the drill 10 is rotated counterclockwise about its axis A. In accordance with the present invention, each of the cutting inserts 30, 31 is generally triangular in shape and is formed with a specially configured corner. As will become apparent subsequently, the use of triangular inserts enables a full circumference of the hole 11 to be cut during each one-half revolution of the drill 10 while permitting the tip end portion of the drill body 13 to be sufficiently strong to withstand heavy cutting forces imposed on the inserts. More specifically, each of the inserts 30 and 31 is made from a block of tungsten carbide or other suitable cutting material and may be formed by modifying a conventional triangular insert of the type furnished commercially by several insert manufacturers. By way of example only, each insert may, before modification, be a type TNMG-432 insert. The insert 30 is shown in detail in FIGURES 4 to 7, it being understood that the insert 31 is identical to the insert 30. As shown, the insert 30 is generally in the shape of an equilateral triangle and includes three sides or edge surfaces 33, 34 and 35 of substantially equal length and joining one another at three corners 36, 37 and 38. The three edge surfaces extend between two oppositely facing and generally planar face surfaces 40 and 41. In the original insert prior to modification, all three edge surfaces extend perpendicular to the face surfaces throughout the entire length of each edge surface and thus the original insert itself is of that type which is known in the art as a negative insert. Each face surface 40, 41 of each insert is formed with a conventional chip-breaking groove 42 (FIGURES 4 and 6) which is triangular in shape and which is located just inwardly of the periphery of the face surface. When each insert 30, 31 is properly seated in its respective pocket 20, 21 as shown in FIGURE 3, the face surface 40 of the insert faces in the direction of rotation and defines a cutting face. A cutting edge 45 is defined at the junction of the face surface 40 and the edge surface 34 and, as the cutting edge proceeds from the corner 36 toward the corner 37, it is straight along most of its length as indicated at 46. Upon approaching the corner 37, the cutting edge 45 starts curving convexly and curves convexly out of the plane of the face surface 40 and toward the plane of the face surface 41 as the cutting edge proceeds around the corner. The curved portion 47 of the cutting edge 45 terminates at an inner point 48 (FIGURE 5) located precisely on or just infinitesimally short of a line extending through the axis A and paralleling the straight portion 46 of the cutting edge. From the inner termination point 48 of the curved cutting edge portion 47, the inner edge surface 35 of the insert is dished outwardly as indicated at 49 in FIGURE 5 so as to provide clearance during cutting. No cutting is performed beyond the termination point 48. Formation of the curved portion 47 of each cutting edge 45 is effected by appropriately grinding the portions of the face surface 40 and the edge surface 35 adjacent the corner 37 of the insert 30, 31. As a result, the corner portion of the face surface 40 and the edge surface 35 are convexly curved as indicated at 50 in FIGURE 4. The pockets 20 and 21 for the inserts 30 and 31, respectively, each include a flat platform 55 (FIGURE 1A) against which the face 41 of the insert is seated. Two side walls 56 and 57 project from each platform and are angled relative to one another so as to cause the pocket to be formed with a generally V-shaped configuration. When each insert is located in its respective pocket, the edge surfaces 33 and 35 seat against the side walls 56 and 57, respectively, and thus the corner 38 of the insert points toward the shank end 15 of the drill body 30. A hole 59 (FIGURE 4) is formed through each insert 30, 31 and extends between and perpendicular to the face surfaces 40 and 41 of the insert. To secure the inserts in the pockets 20, 21, a threaded screw or locking pin 60 (FIGURES 2 and 3) extends through each hole 59 and is threaded into a tapped hole 61 (FIGURE 1A) in the platform 55. When the screw is tightened, it clamps the face surface 41 of the insert against the platform 55 and, at the same time, draws the corner 38 of the insert into the corner of the pocket 20, 21 so as to cause the edge surfaces 33 and 35 of the insert to seat tightly against the side walls 56 and 57 of the pocket. The platform 55 of each pocket 20, 21 is inclined relative to the axis A so as to cause the cutting edge 45 of each insert 30, 31 to be disposed at a negative axial rake angle, meaning that the leading cutting face 40 of the insert is located ahead of the cutting edge 45. As a result, the edge surface 34 of each insert is tipped in such a direction as to define a a clearance face and to avoid rubbing against the bottom of the hole 11 during drilling thereof. In this particular instance, the negative axial rake angle is approximately 10 degrees. Each insert 30, 31 is also positioned such that its cutting edge 45 is located at a negative radial rake. That is to say, each cutting edge is positioned ahead of the most nearly adjacent radial line that parallels the cutting edge and thus the corner 36 of the insert behind the cutting edge clears the peripheral wall of the hole 11 so as to avoid rubbing against such wall. Herein, each cutting edge is positioned approximately 3,6 mm (0.140'') ahead of the aforementioned radial line. The cutting edge 45 of each insert 30, 31 is also inclined at a lead angle C (FIGURE 2) of about 8 degrees. As a result of the lead angle, the cutting edge 45 slopes toward the shank end 15 of the body 30 as the edge progresses outwardly toward the peripheral wall of the hole 11. This causes the center portion of the hole to be cut somewhat prior to cutting of the peripheral portion and facilitates initial penetration of the drill 10 into the workpiece 12. With the foregoing arrangement, rotation of the drill 10 causes the cutting edge 45 of each insert 30, 31 to cut across almost a full radius of the hole 11 as is apparent from FIGURE 8. Each cutting edge sweeps around one-half the circumference of the hole during each one-half revolution of the drill and thus the two cutting edges coact to cut the full circumference of the hole every one-half revolution. This enables rapid axial feeding of the drill. Due to the curved portions 47 of the cutting edges 45, cutting occurs very close to the center of the hole 11. To avoid interference between the inserts 30 and 31, the corners 37 of the two inserts must be spaced from one another and thus a generally cylindrical core 70 (FIGURE 8) is left at the bottom of the hole 11 between the inserts. The significance of the triangular inserts 30, 31 is most apparent from FIGURE 8. The inserts are positioned and angled such that the corners 37 are spaced very closely together (i.e., a spacing of between 0,5 and 1,0 millimeter) and thus the core 70 is very small in diameter. Accordingly, the core may be easily snapped off by the edge surfaces 35 adjacent the corners or simply fragmented by the tip end 14 of the drill body 13 as the body advances axially. Because the inserts are triangular, the edge surfaces 35 of the two inserts quickly diverge away from one another at a wide angle X of approximately 44 degrees as the edge surfaces progress from the tip end 14 of the drill toward the shank end thereof. Because of the wide divergence of the edge surfaces 35, significant space exists between the edge surfaces for the metal of the drill body 13. Accordingly, the body portion between the edge surfaces 35 may be comparatively thick and rugged to a point closely adjacent the corners 37 so as to impart strength to the body. In spite of the relatively large thickness of the body between the edge surfaces 35 of the triangular inserts, the fact that the edge surfaces converge toward the tip end 14 of the body allows the corners 37 to be located closely adjacent one another so that an easily breakable core 70 of only small diameter is left between the inserts. Each insert 30, 31 preferably is formed with an alternately usable cutting edge 45' which is formed along the junction of the face surface 41 with the edge surface 33. Other than for location, the cutting edge 45' is identical to the cutting edge 45 and includes straight and curved portions similar to the straight and curved portions 46 and 47 of the cutting edge 45. The straight portion of the cutting edge 45' starts at the corner 36 and extends to a curved portion located at the corner 38. The curved portion of the cutting edge 45' is defined by forming a convexly curved portion 50' (FIGURE 7) on the face 41 of the insert. After the cutting edge 45 of each insert 30, 31 has become worn, the insert may be removed from the pocket 20, 21. By both inverting and indexing the insert, the cutting edge 45' may be brought into active cutting position. Accordingly, each insert includes two alternately usable cutting edges and thus the insert need not be discarded until both edges have been worn. From the foregoing, it will be apparent that the present invention brings to the art a new and improved drill 10 with multi-edged indexable inserts 30 and 31 which cut a full circumference of the hole 11 across virtually its full diameter during each one-half revolution of the drill. As a result, the drill may be fed axially at a rapid rate. Because the inserts are triangular, adjacent corners 37 of the inserts may be positioned very close together and yet a thick section of drill body 13 may be located between the inserts near the corners 37 so as to impart strength to the drill body. | A drill (10) with replaceable cutting inserts comprising an elongated and generally cylindrical body (13) having a predetermined longitudinal axis, said body (13) having a tip end portion (14) with an outer periphery, first and second pockets (20, 21) formed in the tip end portion (14) of said body (13) on generally diametrically opposite sides of said axis, and first and second cutting inserts (30, 31) seated respectively within said first and second pockets (20, 21) and removably secured to said body (13), each of said inserts (30, 31) having multiple sides (33, 34, 35) of substantially equal length and each having first and second substantially flat and parallel faces (40, 41) bounded by said sides (33, 34, 35), there being a corner (36, 37, 38) at the junction of each side of each insert with each adjacent side, one side (34) of each insert (30, 31) having a cutting edge (45) extending transversely of the body (13) adjacent the tip (14) thereof from a first corner (36) located outwardly of said outer periphery to a second corner (37) located short of said axis, each cutting edge (45) being straight (46) upon proceeding from said first corner toward said second corner and curving convexly (47) out of the plane of said first face (40) and toward the plane of said second face (41) upon approaching said second corner (37), said drill (10) being characterized in that each of said inserts (30, 31) is generally triangular and consists of three sides (33, 34, 35) and three corners (36, 37, 38), each of said pockets (20, 21) being generally V-shaped and having a pair of sides (56, 57) which are both inclined relative to said axis and which embrace two sides (33, 35) of the respective triangular insert (30, 31), each triangular insert (30, 31) having said cutting edge (45) defined at the junction of said third side (34) with said first face (40), each insert (30, 31) including an alternately usable cutting edge (45') extending from said first corner (36) to said third corner (38) and defined along the junction of said second face (41) with another of said sides (33) of said insert, said alternately usable cutting edge (45') having a straight portion (46') extending from said first corner (36) and having a convexly curved portion (47') adjacent said third corner (38). The drill as claimed in Claim 1 characterized in that the curvedportion (47) of the cutting edge (45) of each insert (30, 31) terminates short of the plane of said second face (41). The drill as claimed in Claim 2 characterized in that the curved portion (47) of the cutting edge (45) of each insert (30, 31) terminates on or just short of a straight line extending through said longitudinal axis and being parallel to the straight portion (46) of the cutting edge (45). The drill as claimed in any one of the Claims 1 to 3 characterized by first and second flutes (16, 17) formed in said body (13) on generally opposite sides thereof and extending from said tip end portion (14) toward said shank end portion (15), each of said flutes (16, 17) being generally V-shaped in radial cross-section and each being defined by a pair of walls (18, 19), said first pocket (20) being formed adjacent one wall (18) of said first flute (16), said second pocket (21) being formed adjacent the corresponding wall (18) of said second flute (17), each of said pockets (20, 21) being defined by a platform (55) facing in the direction of rotation of said body (13), said sides (56, 57) extending from said platform (55), the apex of the V of each pocket (20, 21) pointing toward the shank end portion (15) of said body (13), one face (41) of each insert (30, 31) being seated against the platform (55) of the respective pocket (20, 21), the opposite face (40) of each insert (30, 31) facing in the direction of rotation of said body (13) and defining a cutting face, the cutting face (40) of each insert (30, 31) being generally flat but being convexly curved toward said platform (55), adjacent said second corner (37) so as to cause said cutting edge (45) to curve convexly (47). | METAL CUTTING TOOLS INC; METAL CUTTING TOOLS | SHALLENBERGER FRED T; SHALLENBERGER, FRED T. |
EP-0490125-B1 | 490,125 | EP | B1 | EN | 19,960,313 | 1,992 | 20,100,220 | new | H01L21 | null | H01L21 | H01L 21/60C4 | Method of mounting semiconductor elements | A method of mounting a plurality of semiconductor elements (2) each having bump electrodes (4) on a wiring board (5) by pressing the semiconductor elements to the wiring board while aligning the electrodes and heating the structure. In the mounting method, one or more heat sinks (1) are previously joined to the backs opposite to the surfaces with the bump electrodes formed thereon of the semiconductor elements. | BACKGROUND OF THE INVENTION Field of the InventionThe present invention relates to a method of mounting a plurality of semiconductor elements on a wiring board. Description of the Related Art When a plurality of semiconductor elements are joined to a wiring board by face down bonding, the following method has been carried out conventionally. That is, the plurality of semiconductor elements are mounted on the wiring board by pressing the plurality of semiconductor elements having bump electrodes with soldering bumps formed thereon to the wiring board while aligning the electrodes to fix them temporarily and then heat-melting the soldering bumps. WO-A-8 701 509 also discusses the mounting of a semiconductor chip onto a circuit substrate by way of using bump electrodes. The bump electrodes may be supplied on the chips or on the substrates in bumped bonding operations. As the heat produced in the semiconductor element thus mounted is compelled to escape via the bump electrodes toward the wiring board, the thermal resistance has been extremely high. This has posed a serious problem particularly when the power consumption of such a semiconductor element is large. As a result, there has generally been employed a method of providing a heat sink as a radiation path for semiconductor elements ( Handbook of Semiconductor Mounting Technique compiled by Koshi Nihei, Masao Hayakawa and Fumio Miyashiro, K.K. Science Forum (1986)). However, the above method is still problematical because the heat sink is joined to a plurality of semiconductor elements after the elements are joined to a wiring board by face down bonding. In other words, slants of the semiconductor elements, variations of their thickness and the like tend to cause bad contact between the heat sink and the semiconductor elements. On the other hand, there is taught in JP-A-63 252 432 a method of mounting a semiconductor device onto a circuit substrate involving attaching the semiconductor device to a heat sink before the composite structure is mounted onto the circuit substrate. The face down bonding plane of the semiconductor chip or device is placed on and welded together with the facing plane of the heat sink. The other plane of the semiconductor device is then adhered to solder bumps located on the circuit substrate. Thereafter, a heating step takes place to affect bonding. Although the method taught in this prior art would overcome the problem discussed above, nevertheless, this method only involves the mounting of a single semiconductor device where alignment of the semiconductor device for each method step is achieved with relative ease. Another possibility for mounting semiconductor devices onto a wiring substrate is described in EP-A-3 44 702. Here, a holder for the plurality of semiconductor devices is employed which has a respective plurality of recesses formed therein for locating the individual semiconductor devices. The holder containing the semiconductor devices is mounted indirectly to the wiring substrate by way of an intermediate electrical conducting member. Hence, accurate stacked alignment of the holder containing the semiconductor devices, the intermediate electrical connecting member and the wiring substrate is necessary in order to achieve proper electrical connection which involves intricate and time-consuming effort. SUMMARY OF THE INVENTIONThus, the object of the present invention is to overcome the limitations of the prior art methods and therefore provide a method of mounting semiconductor elements which ensures that a plurality of semiconductor elements to be mounted on a wiring board by face down bonding are made to contact respective radiation fins or heat sinks to reduce their thermal resistance while achieving accurate alignment which is not time-consuming and thus simplifies the method of mounting. In order to accomplish the above object, a method of mounting semiconductor elements according to the present invention comprises the steps set out in claim 1. Since the bump electrodes are joined to electrodes on the wiring board by face down bonding after the radiation means is joined to the backs opposite to the surfaces with the bump electrodes formed thereon of the semiconductor elements, the radiation means and the semiconductor elements are made to contact certainly even though the semiconductor elements vary in thickness or slant, so that the thermal resistance therebetween is reduced. Furthermore, since a resist pattern is formed on the radiation means for aligning the semiconductor elements therewith, the semiconductor elements can be positioned very accurately relative to the radiation means. In the case of mounting the semiconductor devices onto a wiring board, then only the positioning of the radiation means or heat sink is required and the positioning of the individual semiconductor elements is not required. BRIEF DESCRIPTION OF THE DRAWINGSFig. 1 is an explanatory diagram for explaining a method of mounting semiconductor elements. Figs. 2 and 3 are explanatory diagrams for explaining a method of mounting semiconductor elements according to a first embodiment of the present invention: Fig. 2 illustrates a process of joining semiconductor elements to a heat sink; and Fig. 3 illustrates a process of joining the semiconductor elements to a wiring board by face down bonding. Figs. 4 and 5 are explanatory diagrams for explaining a method of mounting semiconductor elements according to a second embodiment of the present invention: Fig. 4 illustrates a process of joining semiconductor elements to a wiring board by face down bonding; and Fig. 5 illustrates self-alignment of the semiconductor elements. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTSHereinafter, two embodiments of the present invention will be described in detail with reference to the accompanying drawings. Embodiment not forming part of the claimed inventionFirst, as shown in Fig. 1, heat sinks 1 are joined to a plurality of semiconductor elements 2, respectively. As bump electrodes with soldering bumps 4 formed thereon are arranged on the surface of each semiconductor element 2, the heat sink 1 is joined to the back on the opposite side thereof. In this case, AuSn or the like is used to join the semiconductor elements 2 to the respective heat sinks 1 respectively. Then the plurality of semiconductor elements 2 are joined to a wiring board 5 by face down bonding. More specifically, the semiconductor elements 2 are mounted on the wiring board 5 by pressing the semiconductor elements 2 to the wiring board 5 while aligning the electrodes to fix them temporarily and then heat-melting the soldering bumps 4. Subsequently, molding resin 6 is formed among the wiring board 5, the semiconductor elements 2 and the heat sinks 1 so as to reinforce them. A resin material having good thermal conductivity is suitable for the molding resin 6. As seen from the foregoing description, the heat sinks 1 and the semiconductor elements 2 are previously joined to each other before the semiconductor elements 2 and the wiring board 5 are joined by face down bonding to ensure that the semiconductor elements 2 come in contact with the heat sinks 1, so that thermal resistance therebetween becomes reducible in this way. Even though the plurality of semiconductor elements 2 differ in thickness or they are mounted on the wiring board 5 while being slanted, the contacts between the semiconductor elements 2 and the heat sinks 1 are established for certain. Accordingly, even though the power consumption of the semiconductor elements 2 mounted on the wiring board 5 is large, the heat generated therefrom is allowed to quickly escape from the heat sinks 1. Reliability of the elements is thus improved. Further, since the semiconductor elements 2 and the wiring board 5 are reinforced with the molding resin 6, no deficiency in their strength arises. Although the molding resin has been used in the above embodiment, the use of such molding resin may be omitted if the soldering bumps 4 provide satisfactory junctions. Although the soldering bumps 4 have been used in the above embodiment, Au, AuSn, In bumps or the like may be used instead. First Embodiment of the inventionFirst, as shown in Fig. 2, a resist pattern 3 is formed on the undersurface of a heat sink 1 for use as a radiation fin. The resist pattern 3 is used for aligning a plurality of semiconductor elements 2 and formed by photolithography, for instance. For this reason, the shape of an opening of the resist pattern 3 is rendered consistent with the exterior of each semiconductor element and the openings are provided corresponding to positions where the semiconductor elements are subjected to face down bonding. On the other hand, a plurality of bump electrodes with soldering bumps 4 projectively formed thereon are disposed on the surface of each semiconductor element 2. Subsequently, as shown in Fig. 2, the backs of the semiconductor elements 2 opposite to the surfaces with the bump electrodes formed thereon are positioned on and joined to the heat sink 1. In this case, AuSn or the like is used to join the semiconductor elements 2. Then the plurality of semiconductor elements 2 are joined to a wiring board 5 by face down bonding as shown in Fig. 3. More specifically, the semiconductor elements 2 are mounted on the wiring board 5 by pressing the semiconductor elements 2 to the wiring board 5 while aligning the electrodes to fix them temporarily and then heat-melting the soldering bumps 4. As seen from the foregoing description, the heat sink 1 and the plurality of semiconductor elements 2 are previously joined together before the semiconductor elements 2 and the wiring board 5 are joined by face down bonding to ensure that the semiconductor elements 2 come in contact with the heat sink 1 without slants of all the surfaces of the semiconductor elements 2 against the corresponding surface of the heat sink 1, so that the thermal resistance therebetween is reducible in this way. Accordingly, even though the power consumption of the semiconductor elements 2 mounted on the wiring board 5 is large, the heat generated therefrom is allowed to quickly escape from the heat sink 1. Reliability of the elements is thus improved. The resist pattern has been used to position the plurality of semiconductor elements relative to the heat sink in this embodiment. Second EmbodimentIn this embodiment, a resist pattern 3 is formed on the undersurface of a heat sink 1 and a plurality of semiconductor elements 2 are joined to the heat sink 1, in the same manner as in the second embodiment. However, solder 8 (see Fig. 5) having a melting point lower than that of soldering bumps 4 is used to join the semiconductor elements 2. The positioning accuracy of the semiconductor elements 2 may be defined liberally: e.g., ±50 µm in this embodiment instead of ±10 µm conventionally specified for a bump having a diameter of 80 µm and an electrode of wiring board 5 having a diameter of 100 µm. Then the semiconductor elements 2 are joined to the wiring board 5 by face down bonding as shown in Fig. 4. More specifically, the semiconductor elements 2 are mounted on the wiring board 5 by pressing the semiconductor elements 2 to the wiring board 5 while aligning the electrodes to fix them temporarily and then heat-melting the soldering bumps 4. Even if the semiconductor elements 2 are accurately positioned relative to the wiring board 5 at this stage, the semiconductor elements are self-aligned and automatically moved to respective accurate positions for mounting. In other words, a plurality of recessed or concave electrodes 7 are bored in the wiring board 5 and as these electrodes 7 correspond in position to the soldering bumps 4 of the respective bump electrodes, the electrodes 7 and the bumps 4 are unable to fit together completely unless they are perfectly held in position. The soldering bumps 4 will fail to fit into the recessed electrodes 7 completely as shown in Fig. 5 if the positioning accuracy of both is at approximately ±50 µm. However, the semiconductor elements 2 are temporarily fixed to the wiring board 5 in such a state that the leading ends of the soldering bumps remain fitted in the electrodes 7, and the force of moving the soldering bumps to the center positions of the electrodes in that state. When heating is applied subsequently, the low melting point solder 8 melts before the soldering bumps 4 melt and the semiconductor elements 2 are caused to slide on the heat sink 1 into accurate positions respectively due to the force of moving the soldering bumps 4 to the center positions of the recessed electrodes 7. Thereafter, if heating is continuously applied, the solder bumps 4 melt, whereby the recessed electrodes 7 and the bump electrodes become joined. When heating is stopped later, the solder bumps solidify first and then the low melting point solder 8 solidifies. As seen from the foregoing description, the heat sink 1 and the semiconductor elements 2 are joined before the semiconductor elements 2 and the wiring board 5 are joined by face down bonding to ensure the contact between the semiconductor elements 2 and the heat sink 1, so that thermal resistance therebetween is reduced. Moreover, as the semiconductor elements are moved automatically by self-alignment to respective accurate positions relative to the wiring board, no high-accurate positioning technique is required. With this arrangement, the mounting time is shortened, thus improving reliability. | A method of mounting semiconductor elements comprising the steps of: providing a plurality of semiconductor elements (2), each of said semiconductor elements having first and second surfaces and having bump electrodes (4) on said first surface; forming a resist pattern (3) on a heat radiation means (1) for aligning said semiconductor elements (2); joining the resist pattern side (3) of said heat radiation means (1) to said second surface of said semiconductor elements (2); pressing said semiconductor elements with said heat radiation means (1) joined thereon to a wiring board (5) while aligning the bump electrodes (4); and heating to mount said semiconductor elements on said wiring board. The method according to claim 1, wherein said heat radiation means (1) includes a plurality of heat sinks corresponding to said semiconductor elements respectively. The method according to claim 1, wherein said heat radiation means includes a single heat sink. The method according to claim 1, further comprising a step of forming molding resin (6) among said wiring board, said semiconductor elements and said heat radiation means after the heating step. The method according to claim 1, wherein electrodes of said wiring board (5) are formed in a convex shape. The method according to claim 1, wherein electrodes (7) of said wiring board (5) are formed in a concave shape. The method according to claim 6, wherein solder (8) having a melting point lower than that of the material of said bump electrodes is used to join said semiconductor elements to said heat radiation means. | SUMITOMO ELECTRIC INDUSTRIES; SUMITOMO ELECTRIC INDUSTRIES, LTD. | MIKI ATSUSHI; NISHIGUCHI MASANORI; MIKI, ATSUSHI; NISHIGUCHI, MASANORI; Miki, Atsushi, c/o Yokohama Work of; Nishiguchi, Masanori, c/o Yokohama Work of |
EP-0490127-B1 | 490,127 | EP | B1 | EN | 19,950,208 | 1,992 | 20,100,220 | new | G21C3 | B21D41, G21C21 | G21C21, G21C3 | S21Y2:303, S21C3:10, G21C 21/02, S21Y4:40, S21C21:02, G21C 3/10, S21Y2:302 | Method of forming a gripper cavity in a fuel rod end plug | A method of forming a gripper cavity (44) in a nuclear fuel rod end plug (42) includes the basic steps of providing an end plug blank (46) having an internal bore (48) of substantially uniform diameter that opens at an annular outer rim (50) on the end plug blank, cold forming the end plug blank to produce an intermediate end plug (52) in which the annular outer rim (50) is transformed into a conical outer rim (54) having a rounded internal surface (56) that defines an inlet opening (58) to the internal bore (48) of a diameter less than that of the internal bore (48), and removing an external layer (60) of material from the intermediate end plug (52) and an internal layer (62) of material from the rounded internal surface (56) of the conical outer rim (54) to produce a finished end plug having an internal gripper cavity (44) composed of the internal bore (48) and a cylindrical internal surface (64) defining the inlet opening (58) to the internal bore (48) and being of smaller diameter than the internal bore (48). | The present invention relates generally to fabrication of nuclear fuel rods and, more particularly, is concerned with a method of forming a gripper cavity in a fuel rod end plug. In a typical nuclear reactor, such as a pressurized water type, the reactor core includes a large number of fuel assemblies each of which is composed of top and bottom nozzles with a plurality of elongated transversely spaced guide thimbles extending longitudinally between the nozzles and a plurality of transverse support grids axially spaced along and attached to the guide thimbles. Also, each fuel assembly is composed of a plurality of elongated fuel elements or rods transversely spaced apart from one another and from the guide thimbles and supported by the transverse grids between the top and bottom nozzles. The fuel rods each contain fissile material and are grouped together in an array which is organized so as to provide a neutron flux in the core sufficient to support a high rate of nuclear fission and thus the release of a large amount of energy in the form of heat. A liquid coolant is pumped upwardly through the core in order to extract some of the heat generated in the core for the production of useful work. Each fuel rod includes nuclear fuel pellets and the opposite ends of the rod are closed by upper and lower end plugs to hermetically seal the rod. A cavity is formed in the lower end plug as part of the forming of the end plug according to US-A-4716018. Subsequently, a groove is formed in the cavity by a secondary machining operation. The groove is provided in order to assist in assembling of the fuel assembly by insertion of the fuel rods into the grids of the fuel assembly. The groove in the cavity enables a gripping mechanism, such as disclosed in US-A-4 966 745, to enter the lower plug cavity, expand into the groove, and then pull the fuel rod at the lower end plug through the grip of the fuel assembly already attached to the guide thimbles. Several problems are associated with the current approach of machining the groove in the cavity. First, attaining the desired cavity and groove configuration requires an excessive amount of machining at a cost higher than the material cost of the bottom end plug itself. About one-half of the machining cost goes toward forming the groove in the cavity. Second, the fabrication of the groove is currently performed by an operator and thus depends on the operator doing it properly. However, occasionally the groove is left out completely due to operator oversight which creates fuel rod loading problems at final assembly. Third, sometimes the gripper mechanism shears out the material in the end plug due to high loading force and stress on the end plug. Consequently, a need exists for a different approach to fabrication of the cavity and groove in the bottom end plug for the nuclear fuel rod so as to avoid the problems associated with the current techniques. Accordingly, the present invention is directed to a method of forming a gripper cavity in a nuclear fuel rod end plug. The cavity forming method comprises the steps of: (a) providing an end plug blank having an internal bore of substantially uniform diameter that opens at an annular outer rim on the end plug blank; (b) cold forming the end plug blank to produce an intermediate end plug in which the annular outer rim is transformed into a conical outer rim having a rounded internal surface that defines an inlet opening to the internal bore of a diameter less than that of the internal bore; and (c) removing an external layer of material from the intermediate end plug and an internal layer of material from the rounded internal surface of the conical outer rim to produce a finished end plug having an internal gripper cavity composed of the internal bore and a cylindrical internal surface defining the inlet opening to the internal bore and of smaller diameter than the internal bore. The cold forming includes rotating the end plug blank about a longitudinal axis, and concurrently advancing a plurality of rollers into contact with the annular outer rim on the end plug blank until the annular outer rim is transformed into the conical outer rim. In the course of the following detailed description, reference will be made to the attached drawings in which: Fig. 1 is a side elevational view, with parts partially sectioned and broken away, of a prior art nuclear fuel assembly. Fig. 2 is a prior art lower end plug fabricated by the machining method of the prior art according to US-A-4 716 018 and employed by the nuclear fuel rods of the prior art fuel assembly of Fig. 1. Fig. 3 is a lower end plug fabricated by a gripper cavity forming method of the present invention and which can be employed by the fuel rods of the fuel assembly of Fig. 1. Fig. 4 is a side elevational view, partly in longitudinal section, of an end plug blank formed after performance of initial steps of the method of the present invention. Fig. 5 is a side elevational view of a rolling tool used in roll forming step of the forming method of the present invention. Figs. 6-8 are side elevational views, partly in longitudinal section, of the end plug at successive stages of completion after performance of intermediate and final steps of method of the present invention. Referring now to the drawings, and particularly to Fig. 1, there is illustrated a prior art pressurized water nuclear reactor fuel assembly, represented in vertically foreshortened form and being generally designated by the numeral 10. The fuel assembly 10 basically includes a lower end structure or bottom nozzle 12 for supporting the assembly on a lower core plate (not shown) in the core region of a reactor (not shown), and a number of longitudinally extending guide tubes or thimbles 14 which project upwardly from the bottom nozzle 12. The assembly 10 further includes a plurality of transverse grids 16 axially spaced along and mounted to the guide thimbles 14 and an organized array of elongated fuel rods 18 transversely spaced and supported by the grids 16. Also, the assembly 10 has an instrumentation tube 20 located in the center thereof and an upper end structure or top nozzle 22 removably attached to the upper ends of the guide thimbles 14 to form an integral assembly capable of being conventionally handled without damaging the assembly parts. As mentioned above, the fuel rods 18 in the array thereof in the assembly 10 are held in spaced relationship with one another by the grids 16 spaced along the fuel assembly length. Each fuel rod 18 includes nuclear fuel pellets 24 and the opposite ends of the rod are closed by upper and lower end plugs 26, 28 to hermetically seal the rod. Commonly, a plenum spring 30 is disposed between the upper end plug 26 and the pellets 24 to maintain the pellets in a tight, stacked relationship within the rod 18. The fuel pellets 24 composed of fissile material are responsible for creating the reactive power of the nuclear reactor. A liquid moderator/coolant such as water, or water containing boron, is pumped upwardly through the fuel assemblies of the core in order to extract heat generated therein for the production of useful work. In assembling the fuel assembly 10, it is conventional practice, first, to attach the transverse grids 16 to the longitudinally extending guide thimbles 14 at predetermined axially spaced locations therealong to provide a fuel assembly skeleton. Next, the fuel rods 18 are loaded by passing them through the cells of the grids 16. Typically, a fuel rod loader (not shown) is used which pulls the fuel rods 18 into the fuel assembly skeleton, passing them through the grid cells. The loader has a rod gripper which is, first, inserted through the grid cells, next, coupled to the lower end plug 28 of the fuel rod 18, and, lastly, withdrawn back through the grids 16, pulling the attached fuel rod 18 into the grids. After all fuel rods 18 have been loaded by repeating these operations of the gripper, the bottom and top nozzles 12, 22 are then attached to the lower and upper ends of the guide thimbles 14 to complete the fuel assembly. Referring to Fig. 2, there is illustrated a prior art lower end plug 28 having a generally cylindrical body 32 with an outer tapered nose 34, a generally cylindrical internal cavity 36 formed in the body 32 and open at a flat end surface 38 on the tapered nose 34, and an annular groove 40, of larger diameter than the cavity 36, defined in the cavity 36 of the end plug 28. The fuel rod gripper, disclosed in the U.S. patent application referred earlier and the disclosure of which is incorporated herein by reference, mates with the end plug cavity 36 and groove 40 for connecting with the fuel rod 18 to pull it through the transverse grids 16. The gripper includes a plurality of fingers having forward end portions with generally outwardly-projecting arcuate rim portions thereon. The fingers can assume a collapsed condition in which a rim formed by the rim portions is contracted to an outside diameter less than that of the lower end plug cavity 36 permitting the fingers at the rim to be inserted into or withdrawn from the end plug cavity 36. The fingers can also assume an expanded condition in which the rim formed by the rim portions on the fingers is expanded to an outside diameter greater than that of the lower end plug cavity 36 preventing the fingers at the rim to be inserted into or withdrawn from the end plug cavity 36. In the expanded condition, the rim portions extend outwardly into the internal circumferential or annular groove 40 formed in the cavity 36 of the lower end plug. So expanded, the rod gripper can be retracted, or withdrawn, by the fuel rod loader to pull the fuel rod 18 into the fuel assembly 10. Heretofore, the internal cavity 36 and annular groove 40 have been formed by machining the end plug 28 at high cost in proportion to the cost of materials and other fabrication operations. Further, the machining of the groove 40 is carried out as a secondary operation performed subsequent to fabrication of the external configuration of the end plug 28 and the internal cavity 36. In addition to high cost, occasionally through oversight, the operator would fail to machine the internal groove 40 at all, causing subsequent disruption of the assembling of the fuel rod 18 through the grids 16 due to the absence of a way for the fuel rod gripper to grip the fuel rod 18. Referring to Figs. 3 to 8, there is illustrated a lower end plug 42 having an internal gripper cavity 44 fabricated by the cavity forming method of the present invention. The gripper cavity forming method of the present invention substantially overcomes the problems associated with the prior art approach of separately machining the gripper cavity 36 and groove 40. Basically, the gripper cavity forming method of the present invention includes the basic steps of, initially, providing an end plug blank 46, as shown in Fig. 4, having an internal bore 48 of substantially uniform diameter that opens at an annular outer rim 50 on the end plug blank 46, next, cold forming the end plug blank 46, as shown in Fig. 5, to produce an intermediate end plug 52, as shown in Fig. 6, in which the annular outer rim 50 is transformed into a conical outer rim 54 having a rounded internal surface 56 that defines an inlet opening 58 to the internal bore 48 of a diameter less than that of the internal bore 48, and, then finally, removing an external layer 60 of material from the intermediate end plug 52 and an internal layer 62 of material from the rounded internal surface 56 of the conical outer rim 50 to produce a finished end plug 42 having the internal gripper cavity 44, as seen in Figs. 3 and 8, composed of the internal bore 48 and a cylindrical internal surface 64 which defines the inlet opening 58 to the internal bore 48 and is of smaller diameter than the internal bore. Referring to Figs. 4-8, there is illustrated the successive stages of completion of the end plug 42 of Fig. 3 by performance of the steps of forming the gripper cavity 44 in the end plug 42. The initial steps of the gripper cavity forming method of the present invention result in the formation of an end plug blank 46 with the internal bore 48, as seen in Fig. 4. More particularly, the end plug blank 46 is formed by mounting a solid bar 66 of material on a conventional rotatable spindle (not shown) and machining the end of the bar 66 using a conventional cutting tool (not shown) to provide the profile of the exterior of the end plug blank 46 shown in Fig. 4. Then, the internal bore 48 having the constant uniform diameter is drilled into the end surface 66A of the solid bar 66 by using a conventional rotary drill bit (not shown). By way of example, the diameter of the internal bore 48 can be 4,2 mm. The end plug blank 46 so produced has a longitudinal axis 46A and is composed of an inner portion 70 connected to the remainder of the solid bar 66, an outer portion 72, and a middle portion 74 interconnecting the inner and outer portions 70, 72. The inner portion 70 has a cylindrical external surface 70A of a first diameter. The outer portion 72 has a cylindrical external surface 72A of a second diameter being less than the first diameter of the inner portion 70. As an example, the second diameter can be 6,25 mm and the first diameter 9,4 mm. The middle portion 74 has a conical external surface 74A which extends between and interconnects the external surfaces 70A, 72A of the inner and outer portions 70, 72. As an example, the included angle between the conical external surface 74A and the longitudinal axis 46A can be 37°. Also, the inner, middle and outer portions 70, 74, 72 extend along and symmetrically about the longitudinal axis 46A of the end plug blank 46. The internal bore 48 formed by drilling the end plug blank 46 is open at the end surface 66A and extends through the outer and middle portions 72, 74 thereof and into the inner portion 70 thereof so as to define a continuous internal cylindrical bore surface 76. The internal cylindrical bore surface 76 has the aforementioned constant uniform diameter and extends along and concentrically about the longitudinal axis 46A of the end plug blank 46. The internal bore surface 76 is also concentric with the cylindrical external surfaces 70A, 72A of the inner and outer portions 70, 72 of the end plug blank 46 and form with the outer portion the annular cylindrical outer rim 50 on the end plug blank 46. Referring to Figs. 5 and 6, there is illustrated the intermediate cold forming step of the cavity forming method and the intermediate stage of completion of the end plug 42. A rolling tool 78 is provided for performing cold forming, or rotary forging, of the end plug blank 46 to produce the intermediate end plug 52 shown in Fig. 6. The cold forming step transforms the annular cylindrical outer rim 50 of the end plug blank 46 having the cylindrical external and internal surfaces 72A, 76 into the conical outer rim 54 having the rounded internal surface 56 and a conical external surface 54A. The rounded internal surface 56 now defines the inlet opening 58 to the internal bore 48 which has a smaller diameter than the internal bore. As an example, the inlet opening 58 can typically range from 2,8 - 3,05 mm compared to 4,2 mm for the diameter of the internal bore 48. The conical external surface 54A of the conical outer rim 54 provides an extension of the conical external surface 74A of the middle portion 74 of the end plug blank 46. The rolling tool 78 includes a tool mounting shank 80 having a head end 82 and a plurality of hardened metal, such as steel, rollers 84 rotatably mounted by axles 86 on the head end 82. Although only two rollers 84 are shown, typically three rollers would be provided, oriented at an included three-dimensional angle equal to the angle made by the conical external surface 74A with the longitudinal axis 46A of the end plug blank 46, which in the example given above is 37°. Thus, the cold forming step is performed by concurrently rotating the end plug blank 46 about its longitudinal axis 46A through rotation of the machine spindle and advancing the rollers 84 along the longitudinal axis 46A into contact with the annular outer rim 50 on the end plug blank 46 until the annular outer rim 50 is transformed, or reformed, into the configuration of the conical outer rim 54, which occurs when the rollers become seated against the conical external surface 74A. The rotation of the end plug blank 46 engaged with the rollers 84 drives the rotation of the rollers. Referring to Figs. 7 and 8, there is illustrated the final machining step of the cavity forming method and the final stage of completion of the end plug 42. The machining is performed by a conventional cutting tool (not shown). The intermediate end plug 52 is transformed to produce the finished end plug 42 by removing the external layer 60 of material (that being between the dashed surface 88 and the external surfaces 70A, 74A, 54A) from the intermediate end plug 52 and the internal layer 62 of material (that being between the dashed surface 90 and the rounded internal surface 56) from the rounded internal surface 56 of the conical outer rim 54. The finish machining removes impurities embedded in the external surfaces of the intermediate end plug 52 as a result of the rolling contact with the rollers 84. The finished end plug 42 now includes the internal gripper cavity 44 composed of the internal bore 48 and the continuous cylindrical internal surface 64 which define the inlet opening 58 to the internal bore 48. The surface 64 of the inlet opening 58 is of a smaller diameter than the internal bore 48 which enables the gripping mechanism to grip the end plug 42 and pull the fuel rod 18 through the grids 16. The finished end plug 42 is severed from the bar 66 by a conventional cutting tool 92, as seen in phantom outline in Fig. 8. | A method of forming a gripper cavity (44) in a nuclear fuel rod end plug (42), comprising the steps of: (a) providing an end plug blank (46) having an internal bore (48) of substantially uniform diameter that opens at an annular outer rim (50) on said end plug blank (46); (b) cold forming said end plug blank (46) to produce an intermediate end plug (52) in which said annular outer rim (50) is transformed into a conical outer rim (54) having a rounded internal surface (56) that defines an inlet opening (58) to said internal bore (48) of a diameter less than that of said internal bore (48); and (c) removing an external layer (60) of material from said intermediate end plug (52) and an internal layer (62) of material from said rounded internal surface (56) of said conical outer rim (54) to produce a finished end plug (42) having an internal gripper cavity (44) composed of said internal bore (48) and a cylindrical internal surface (64) defining said inlet opening (58) to said internal bore (48) and being of smaller diameter than said internal bore (48). The method as recited in Claim 1 wherein said end plug blank (46) has a longitudinal axis (46a) and is composed of an inner portion (70) having an external surface (70A), an outer portion (72) having an external surface (72A) of a diameter less than that of said external surface (70A) of said inner portion (70), and a middle portion (74) having a conical external surface (74A) extending between and interconnecting said external surfaces (70A, 72A) of said inner and outer portions (70, 72). The method as recited in Claim 2 wherein said internal bore (48) opens at said outer portion (72) and extends through said outer and middle portions /72, 74) and at least partially into said inner portion (70) so as to define said annular outer rim (50) at said outer portion (72). The method as recited in Claim 2 or 3 wherein said intermediate end plug (52) produced by said cold forming has a conical external surfac (54A) that is an extension of said conical external surface (74A) of said middle portion (74) of said end plug blank (46). The method as recited in any of Claims 1 to 4 wherein said providing an end plug blank (46) includes machining a solid bar (66) of material to produce said end plug blank (46). The method as recited in Claim 5 wherein said machining includes drilling said solid bar (66) of material to produce said internal bore (48) of uniform diameter in said end plug blank (46). The method as recited in any of Claims 1 to 6 wherein said cold forming includes rotating said end plug blank (46) about a longitudinal axis (46A) and advancing a plurality of rollers (84) into contact with said annular outer rim (50) on said end plug blank (46) until said annular outer rim (50) is transformed into said conical outer rim (54). | WESTINGHOUSE ELECTRIC CORP; WESTINGHOUSE ELECTRIC CORPORATION | BOATWRIGHT DAVID ANTHONY; YEO DENIS; BOATWRIGHT, DAVID ANTHONY; YEO, DENIS |
EP-0490128-B1 | 490,128 | EP | B1 | EN | 19,960,522 | 1,992 | 20,100,220 | new | C22B34 | C22B34, C01G25, C22B3, C01G27 | C22B3, C22B34, B01D15 | C22B 34/14, C22B 3/44, L01D15:08+S01N30:58C | Zirconium-hafnium production in a zero liquid discharge process | A simple, low cost continuous process for separating and purifying zirconium and hafnium which eliminates liquid waste and facilitates the management of RCRA and LLW wastes is provided. An aqueous zirconium and hafnium - containing feed solution is prepared and fed to a continuously rotating annular chromatograph containing a bed of acid exchange resin. An acid eluant, such as hydrochloric acid, nitric acid, phosphoric acid or the like, is fed through the acid exchange bed while the chromatograph is rotating, which separates the feed into substantially pure zirconium and hafnium fractions and into RCRA and LLW waste fractions. The zirconium and hafnium are processed further into nuclear quality zirconium and hafnium metals. The acid eluant is recycled for reuse in the chromatograph, and the RCRA and LLW waste fractions are disposed of in solid form. | The present invention relates generally to zirconium-hafnium separation processes and specifically to a zirconium-hafnium separation process whereby Zirconium and hafnium chromatographically separated and purified in a single operation, which does not generate liquid waste. Commercial processes currently available for the production of nuclear grade zirconium are variations of a solvent extraction process wherein zircon sand is converted to zirconium metal as a result of a somewhat involved series of steps. This extraction process requires the use of an organic solvent, usually hexone, and various aqueous solutions, including hydrochloric acid. Hafnium, which is chemically similar to zirconium, must be separated from the zirconium. The hexone/thiocyanate/hydrochloric acid system employed for this purpose requires a series of separate extraction and separation columns. The zirconium, organic solvent and thiocyanate recovered from the hafnium separation steps are usually subjected to additional processing to insure that as much zirconium is recovered from the system as possible. The sirconium ultimately recovered from most extraction processes is in the form of pure zirconium oxide (ZrO₂). In a commonly used commercial process, the zirconium oxide is chlorinated to form ZrCl₄, which is purified and subjected to Kroll reduction to produce zirconium metal suitable for nuclear applications. The aqueous and organic liquids used in the process typically include waste metals and other materials that must be properly disposed of. One of the methods of treating these liquid wastes is to place them in holding ponds for future treatment and remediation. However, this is increasingly becoming an unacceptable waste management solution, particularly since federal and state laws relating to waste disposal have become more stringent. The solvent extraction processes effectively separate zirconium from hafnium to produce zirconium of the quality required for use in nuclear reactors and elsewhere in the nuclear industry. However, the increasing concern expressed by the public, the scientific community and the regulatory agencies regarding the waste generated by solvent extraction processes has led the nuclear industry to explore alternative zirconium production methods which do not present the same waste management concerns. For example, the hexone-thiocyanate zirconium extraction process can generate offensive odors, and the waste from both the zircon sand chlorination process and the zirconium raffinate precipitation may include potentially toxic materials which must be properly disposed of. Other zirconium-hafnium separation methods in addition to the aforementioned solvent extraction method have been proposed by the prior art. Ion exchange processes for separating zirconium and hafnium are described in U.S. Patent Nos. 2,546,953 to Street and 2,759,793 to Lister et al., in British Patent No. 755,601 to Lister et al., and in Belgian Patent Publication No. 602,665. Adsorption processes are disclosed in U.S. Patent Nos. 2,571,237 to Hansen and 2,860,956 to Arden et al. In U.S. Patent No. 2,546,953, Street discloses an ion exchange separation process wherein the mixed oxychlorides of zirconium and hafnium are passed through a cationic exchange resin and then recovered with hydrochloric acid. U.S. Patent No. 2,759,793 and British Patent No. 755,601 to Lister et al. also disclose a method of separating zirconium from hafnium using a cationic exchange resin. Zirconium and hafnium in soluble salt form, which can include their oxychlorides, are passed through an acidified cation exchange resin and then eluted with sulfuric acid. The Belgian patent publication No. 602,665 discloses an ion exchange zirconium-hafnium separation and recovery method based on sulfate separation chemistry. Not only do these processes not produce a highly pure zirconium, but waste management is still a problem. In particular, each of these processes generates liquid waste which requires proper disposal. Hansen, in U.S. Patent No. 2,571,237, discloses the absorption of hafnium from a solution of mixed zirconium and hafnium chlorides with silica gel. Organic solvent containing purified zirconium values is then separated from the absorbent. U.S. Patent No. 2,860,956 to Arden et al. also employs an organic solvent to extract the zirconium values from an absorbent containing both zirconium and hafnium. Although the aforementioned separation processes effectively separate zirconium in a usable form from hafnium, they do not avoid the waste management concerns associated with solvent extraction processes. The prior art adsorption processes require organic solvents to isolate the zirconium which must be disposed of. Moreover, the unpleasant odors and the other drawbacks that accompany the use of organic reagents are drawbacks to the contemporary use of these processes. Consequently, the prior art has failed to provide a simple zirconium-hafnium separation process for producing nuclear quality zirconium which eliminates both liquid discharge and organic reagents and which is not accompanied by involved waste management procedures. It is an object of the present invention to provide a simple, low cost process for separating zirconium from hafnium which uses only aqueous reagents to produce substantially pure zirconium and hafnium. Liquid reagents are recycled to eliminate liquid waste discharge, and mixed metal wastes are separated by the present process into RCRA and LLW fractions, thus providing control over and facilitating waste management. In accordance with the present process, a crude zirconium-hafnium hydrolysate feed is prepared from zircon sand and introduced to an acid resin medium at a first point in a continuous annular chromatograph. An aqueous acid eluant is introduced to the chromatograph at a second point angularly displaced from the first point and is passed through the exchange resin as the chromatograph is rotated. The zirconium and hafnium fractions are collected at the bottom of the chromatograph. The rotation of the chromatograph also separates the various waste fractions and impurities, which are collected and disposed of. The acid eluant is recycled and reused. The zirconium and hafnium fractions may be concentrated by exaporation and roasted, separately, to their respective oxides and then chlorinated for reduction to pure zirconium and hafnium metal. The eluant from the evaporator and roaster overheads is condensed and recycled. The present invention will be more fully understood by referring to the following Figures, wherein: Figure 1 is a schematic diagram of the zirconium-hafnium separation process of the present invention; Figure 2 is a side perspective view of one embodiment of a continuous annular chromatograph suitable for use in the process of the present invention; Figure 3 illustrates diagrammatically the separation of zirconium, hafnium and waste fractions produced in the annular chromatograph of Figure 2 by the process of the present invention; and Figure 4 is a graphic illustration of the angular displacement of the zirconium, hafnium and waste fractions separated according to the present process from the feed nozzle as a function of the length of the resin exchange bed. The production of nuclear quality zirconium and hafnium can be achieved with currently available methods. However, as discussed above, these methods are accompanied by waste management concerns which may add to their cost and reduce their overall efficiency. Available zirconium-hafnium separation processes, moreover, involve multiple complex stages to produce zirconium metal of a purity and quality suitable for use in nuclear reactors and similar applications. The process of the present invention is an aqueous zirconium-hafnium chromatographic separation method which separates zirconium and hafnium in a single operation to produce substantially pure zirconium and hafnium while simultaneously separating non-liquid waste to facilitate its disposal. The present process recycles the liquid reagents used to effect the separation and, consequently, generates no liquid waste, which completely eliminates the waste management methods required for available Zr/Hf separation processes that do generate liquid wastes. Finally, the system employed by the present invention is entirely aqueous, which eliminates the unpleasant odors often associated with the organic reagents of the prior art processes. Referring to the drawings, Figure 1 is a schematic illustration of the process of the present invention. The starting material preferred for use in the present process is zircon sand. The zircon sand 10 is chlorinated in the presence of a carbon source 12 in chlorinator 14 at a temperature in the range of 800 to 1100°C. Petroleum coke is the carbon source preferred for this purpose. A carbon/zircon ratio of 21 parts carbon/79 parts zircon has been found to be particularly effective. The gaseous stream 16 from the chlorinator 14 is selectively condensed in a condensor 18. Two streams are produced: a silicon chloride (SiCl₄) by-product stream 20 and a crude (Zr/Hf)Cl₄ fraction 22. The (Zr/Hf)Cl₄ fraction is processed further to form a feed stream which is ultimately separated into zirconium and hafnium metals. The crude (Zr/Hf)Cl₄ fraction 22 is hydrolyzed in a two-step process, which is summarized by the following reactions: ZrCl₄ + 2H₂O → ZrOCl₂ + 2HCl ↑HfCl₄ + 2H₂O → HfOCl₂ + 2HCl ↑ The hydrochloric acid (HCl) byproduct is driven off by partial hydrolysis with water (H₂O) in a first step which takes place in the BEPEX unit 24. This HCl byproduct stream 26, which is anhydrous HCl, is directed to an HCl absorber 28. In the second step, which takes place in a feed prep tank 30, complete dissolution of the (Zr/Hf)Cl₄ fraction is achieved. Alternatively, crude ZrCl₄ could be dissolved directly in a single step. The absence of HCl increases the solubility of zirconium tetrachloride (ZrCl₄) in water. This allows the production of higher feed stock zirconium concentrations than have been possible heretofore. Additionally, the volume of the crude zirconium hydrolysate stream 32 leaving the feed prep tank 30 is significantly reduced, which is the first point in the process at which waste is minimized. Concentrations of up to 270 grams of zirconium per liter can be achieved with this two-stage dissolution process. The currently used solvent extraction process produces concentrations of only 100 to 130 grams of zirconium-containing feed stock per liter. The crude zirconium-hafnium hydrolysate 32 is fed to a continuous annular chromatograph 34. An eluant stream 36, which comprises an acid, as will be described in detail hereinbelow, is directed to the continuous annular chromatograph 34. The zirconium fraction 38 and hafnium fraction 40 are separated and purified of other metal contaminants, specifically, RCRA (transition) metal wastes 42 and LLW (radioactive) metal wastes 44. If the eluant acid concentration is 2.5N, the concentrations of the product fractions separated by the operation of the continuous annular chromatograph 34 can reach approximately 20 grams of product per liter. The zirconium product fraction 38 is directed first to a zirconium concentrator 46 where it is evaporated and then to a spray roaster 48, which is preferably heated by a gas burner 50. The zirconium product fraction 38 is spray roasted to a ZrO₂ product 52. The ZrO₂ is then chlorinated (not shown in the process schematic of Figure 1) and subsequently reduced to zirconium metal. The hafnium product fraction 40 is subjected to the same processing as the zirconium fraction 38. The aqueous hafnium is first concentrated in a concentrator 54 and then spray roasted in a hafnium spray roaster 56 to produce a HfO₂ product 58. The HfO₂ product is chlorinated (not shown) and reduced to hafnium metal. The aqueous RCRA waste fraction 42 and the aqueous LLW waste fraction 44 are subjected to volume reduction and can be disposed of as dry solids. The disposal of these materials as solids is substantially easier than their disposal as aqueous or organic liquids. Moreover, they are separated by the chromatograph so additional processing to separate the RCRA and LLW wastes is not required. This capability provides an additional waste management benefit. The acid eluant 36 is recycled after it has been passed through the continuous annular chromatograph 34. This acid eluant is recycled through an acid absorber such as HCl absorber 28. In addition, acid, typically HCl, from the zirconium spray roaster 48 and the hafnium spray roaster 56 is directed along acid recycle line 60 to the HCl absorber. The acid is stored in an acid feed storage tank 62 from which it is pumped back to the continuous annular chromatograph 34 along an eluant supply line 64. Some acid is typically generated by the present process, usually in the form of HCl. Some of the chlorine supplied to the chlorinator 14 will react with the zircon sand and coke to form the SiCl₄ by-product 20. The remainder of the Cl₂ forms hydrochloric acid 66, which may be combined with the acid eluant and used in the chromatographic separation. Since all barren acid eluant streams are recycled directly to the chromatograph, there are no aqueous wastes to be discharged. Table I below compares the process steps required for the prior art solvent extraction zirconium/hafnium separation and those required for the chromatography process of the present invention. Although the preparation of the zirconium-hafnium feed and the reduction of the separated zirconium and hafnium fractions to their respective metals of these two processes are similar, the actual separation processes differ in significant respects. The prior art solvent extraction process requires at least four rather involved steps, each of which requires separate processing apparatus and aqueous and organic reagents, while the present process achieves an improved separation with a single processing step, a single apparatus, and only recycled aqueous reagents. The continuous annular chromatograph 34 preferred for use in the process of the present invention is shown in Figure 2. A particularly preferred continuously operating chromatograph is the continuous annular chromatograph developed by Oak Ridge National Laboratory. This device comprises an annular stationary phase which is rotated about the axis of an annulus 68. The annulus 68 includes a stationary phase material, such as resin beads, packed between two concentric cylinders 70, 72 of differing diameters with vertical axes to form an annular bed. A feed port (not shown) is provided at a given angular position and one or more eluant ports (not shown) are provided at some angular offset from the feed port. It is preferred to place a layer of glass beads above the stationary phase material, and to feed the eluant on the top of the glass bead layer while feeding the zirconium/hafnium feed stock directly to the top of the stationary phase to prevent any undesired mixing effects. The chromatograph includes a number of product ports 74 set at different angular positions which can be set arbitrarily to accommodate particular operating conditions. Each product port 74 collects an elution volume which has had a particular residence time in the chromatograph. The stationary phase 69 is typically rotated in the annulus 68 at a constant speed so that any vertical segment of the annular bed is above a particular fixed product collection port 74 at a given time after this segment has been loaded with zirconium/hafnium feed stock and eluant. Thus, each product collection port 74 has an angular position which corresponds to a particular elution time for a particular rate of rotation of the stationary phase 69 and for a particular flow rate through the stationary phase. The flow rate through the stationary phase 69 is controlled by the pressure drop across the effective height of the stationary phase and the physical characteristics of the stationary phase, i.e., particle size and packing void volume. This pressure drop may be provided by the hydrostatic head of the feed stock and eluant, but it is preferably provided by pressurizing the device. The pressure required to achieve a particular flow rate is governed by the nature of the stationary phase (i.e., its packing, average particle size and particle size distribution). The smaller the average particle size of the resin beads making up the stationary phase, the larger the pressure drop required to obtain a particular flow rate over a particular effective height will be. However, the separation factor for any given theoretical stage is improved as the average particle size of the resin beads is decreased. Thus, the effective height needed to effect a given degree of separation is decreased as the separation capacity of a unit length (or theoretical stage height) is increased by decreasing the average particle size of the resin beads. A short residence time in the chromatograph allows an increase in the zirconium and hafnium concentration in the product elution volumes. In general, the longer the residence time in the chromatograph is, the more band spreading occurs. Band spreading is a term of art used in this context to describe the phenomenon that can be observed when the longer the residence time is, the larger the proportion of the total elution volume which contains some of the desired product. To obtain all or a certain percentage of this product fraction, it is necessary to collect a volume of eluant which increases with residence time. Thus, the net effect of band spreading is to dilute the metal concentration in the product fractions. The flow rate across the effective height of the stationary phase 69 and the rotational speed of the stationary phase should be coordinated so that a particular product fraction always elutes at the same angular position and, consequently, is always delivered to the same product collection port 74. It is preferred that the chromatograph be operated in a displacement mode wherein no more than about 5 percent, more preferably no more than about 1 percent of the effective column height, is loaded with feed solution before elution is initiated. The angular displacement between the feed port and the eluant port and the speed of rotation of the annular bed are coordinated so that the time interval between loading and elution is just sufficient for the desired degree of penetration. The relationship between the time for loading and the depth of penetration is in turn governed by the flow rate through the annular bed. The displacement may be effected by either an isocratic or a gradient supply of eluant. In the former case, the eluant can simply be supplied from a single port while in the latter case, several ports at successively greater angular displacements from the feed port are utilized. In the gradient mode, elution under the influence of the initial eluant is permitted to proceed until some separation has been effected, and then eluant with a higher concentration is supplied. This increases the migration speed down the column and minimizes the range of elution volumes or times over which a given component or product fraction will exit the column or, in other words, this procedure minimizes the band spreading. Decreasing the elution volumes by gradient elution or by other means increases the concentration of the product in the product fraction. Concentrations greater than about 2 g/l, especially between about 20 and 70 g/l are preferred. It is preferred to maximize the concentration of product because the total volume of fluid to be processed will be reduced. This allows a reduction in the overall size of the system with a consequent reduction in capital and operating expenses. However, practical considerations, such as solubility limits, will constrain the maximum concentrations obtainable. The flow rate down the chromatograph is governed by the pressure drop from the top to the bottom of the chromatograph and the nature of the stationary phase. The smaller the average particle size of the resin beads making up the stationary phase is, the higher the pressure drop that is required to obtain a given flow rate. This relationship is also affected by the particle size distribution of these resin beads. There is, however, a maximum attainable flow rate for any given resin stationary phase which cannot be exceeded by the application of additional pressure. The suppliers of such resins rate them in terms of flow rate per given pressure drop and maximum attainable flow rate. It is preferred to use a stationary phase which will permit flow rates between about 2 and 80, more preferably between about 3 and 20 gallons per minute per square foot of cross sectional area (between about 1.36 x 10⁻³ and 5.43 x 10⁻² m³/sec, more preferably between about 2.04 x 10⁻³ and 1.36 x 10⁻² m³/sec per square meter of cross sectional area). There is a relationship between the achievable flow rates and the effective chromatograph column height needed for a given degree of purity. For a given system of stationary phase and eluant, the theoretical stage separation factor, αs, of the stationary phase will increase as the average particle size of the resin beads of the stationary phase decreases. However, as this particle size decreases, so does the flow capacity of the stationary phase. Thus, there is an inverse relationship between αs and the flow capacity. A higher flow rate will require a greater effective column height to achieve the same degree of separation or product fraction purity. Furthermore, there is the additional constraint that the pressure required to achieve the desired flow rate should not exceed the capability of available pumps, seals and feed tubing. The required pressure is a function of both the pressure drop needed per unit of effective height and the total effective height required for the desired degree of separation. Thus, as the flow capacity of the stationary phase is increased by a change in its physical configuration and, consequently, its theoretical stage separation factor, αs, is decreased, the required effective height and the required overall pressure drop are both increased. On the other hand, as the theoretical stage separation factor, αs, is increased by a change in the resin bead size distribution so that the flow capacity of the stationary phase is decreased, the pressure drop for a given effective height is increased. A pressure drop of less than about 2759 kPa (400 psi), more especially between about 345 and 1042 kPa (50 and 150 psi), is preferred. Thus, to obtain a system with a commercially practical capacity, it is necessary to use a stationary phase which will simultaneously display both a reasonable theoretical stage factor, αs, and a reasonable flow rate per unit of effective height with a reasonable pressure drop. This can be achieved by an appropriate selection of both the capacity of the stationary phase resin and eluant. It is preferred that several product collection ports 74 be used to collect a particular product fraction. This is accomplished by closely spacing these collection ports so that they more than span the angular range of rotation that corresponds to the elution time interval of that particular fraction, but do not extend to angular positions at which any significant portion of any other product fraction is expected to elute. Of course, this requires that the elution time intervals of different product fractions do not substantially overlap. That is, the alpha (αs) values should exceed 1 for all species. This arrangement tends to insure that minor fluctuations in the steady state elution behavior which would cause a slight advancement or retardation of the elution time of the desired product fraction will not result in any loss of this fraction. Figure 3 illustrates diagrammatically separation of the product fractions in the zirconium/hafnium feed solution after the feed solution has been eluted through the stationary phase 69 of the continuous annular chromatograph 34 according to the process of the present invention. A fixed feed inlet 76 is used to load the zirconium/hafnium feed and an eluant inlet 78 is used to direct eluant to the stationary phase 69. Although it is not shown, the eluant inlet 78 is may be connected to several inlet nozzles that direct eluant to various locations along the upper circumference 80 of the stationary phase. As the chromatograph rotates continuously, the product fractions in the feed are separated so that they are angularly displaced from the feed inlet 76 as shown in Figures 3 and 4. The four product fractions of primary concern are the zirconium fraction 38, the hafnium fraction 40, the RCRA waste fraction 42, and the LLW waste fraction 44. An additional product fraction 82 is also shown in Figure 3 which represents any miscellaneous product present in the feed solution other than the four shown in Figure 4. The separated product fractions are collected in the collection vessels 84 as shown in Figure 3 and processed further as described above. Only a single continuous annular chromatograph has been described in connection with the present process. However, any number of continuous annular chromatographs may be employed in the present process. For example, three such chromatographs may be effectively used. Each chromatograph unit would require a supply of zirconium-hafnium feed and would produce the product fractions described above. Table II below sets forth the chromatographic operating conditions preferred for achieving the efficient and effective separation and purification of zirconium and hafnium in accordance with the process of the present invention. Preferred Chromatographic Operating Conditions Range Preferred Feed Stream Concentration10-300 g/L220 g/L Feed SolventWaterWater Stationary PhaseStrong Acid-Weak Acid Exchange ResinStrong Acid e.g., Dowix 21K Stationary Phase Particle Size Mean.01 to 500 microns<100 microns DistributionPolydisperse to MonodisperseMonodisperse MorphologyArbitrarySpherical Mobile Phase (Eluant) SolventWaterWater AcidHClHCl H₂SO₄ HNO₃ H₃PO₄ HC10₄ Concentration 2-6N 2-2.5N for Zr Elution 2.5-4N for Hf Elution Elution ModeGradient and IsocraticGradient The process of the present invention has been demonstrated to be significantly more economical than the solvent extraction method of the prior art. However, additional economies may also be realized by modifying some of the processing steps to substitute passive product recovery methods for the thermal methods described above. For example, membrane processing may be substituted for the thermal evaporation and roasting steps to reduce processing costs. Additionally, waste management costs may also be significantly reduced by the present process. | A process for separating and purifying zirconium and hafnium comprising: (a) preparing an aqueous zirconium and hafnium-containing feed solution; (b) loading said feed solution into an acidic resin medium (69) at a first point (76) on a continuous annular chromatograph (34); (c) feeding an aqueous acid eluant to said resin medium (69) at a second point (78) angularly displaced from said first point (76) on said chromatograph (34) to elute said feed solution; (d) continuously rotating said chromatograph (34) during steps (b) and (c) while said feed solution and said eluant diffuse through said resin medium (69); (e) separately collecting a substantially pure zirconium fraction (38), a substantially pure hafnium fraction (40) and at least one waste fraction (42, 44) at locations on the annular chromatograph (34) angularly displaced from said first point (76); (f) further processing said zirconium fraction (38) and said hafnium fraction (40) to produce nuclear quality zirconium metal and hafnium metal; and (g) recycling said acid eluant for reuse in step (c). The process described in claim 1, wherein step (a) comprises the steps of: (i) chlorinating zircon sand in the presence of carbon to produce a crude (Zr/Hf)Cl₄ fraction; (ii) partially hydrolyzing said crude (Zr/Hf) Cl₄ with water to produce (Zr/Hf)OCl₂ and HCl; (iii) removing the HCl component of step (ii); and (iv) completely dissolving said (Zr/Hf)OCl₂ in water. The process described in claim 1, wherein step (f) comprises the steps of: (i) concentrating each of said hafnium fraction (40) and said zirconium fraction (38); (ii) spray roasting each of said concentrated hafnium and zirconium fractions to produce HfO₂ and ZrO₂; and (iii) first chlorinating and then reducing said HfO₂ and said ZrO₂ to produce substantially pure nuclear grade hafnium and nuclear grade zirconium. The process described in claim 1, wherein said resin medium (69) is selected from the group consisting of strong acid exchange resins and weak acid exchange resins. The process described in claim 4, wherein said aqueous acid eluant is selected from the group consisting of HCl, H₂SO₄, HNO₃, H₃PO₄ and HClO₄. The process described in claim 5, wherein the concentration of said acid eluant is 1 to 6 Normal. The process described in claim 6, wherein said resin medium (69) is a strong acid exchange resin, said aqueous acid eluant is HCl, and the concentration of said eluant is 2 to 4 Normal. The process described in claim 1, wherein two said waste fractions (42, 44) are collected and said waste fractions (42, 44) comprise a transition metal fraction (42) and a radioactive metal fraction (44). The process described in claim 4, wherein said resin medium (69) is a particulate material having a mean particle size of 0.1 to 500 microns. The process described in claim 7, wherein said acid eluant is fed to said resin medium (69) in a gradient elution mode. A continuous process for producing substantially pure nuclear grade zirconium from zircon sand which generates no liquid waste and minimizes non-liquid waste, said process comprising: (a) preparing an aqueous ZrOCl₂ feed solution by first chlorinating said zircon sand to produce ZrCl₄ and then hydrolyzing said ZrCl₄ to ZrOCl₂ in two steps to substantially completely dissolve said ZrOCl₂ in water; (b) feeding said ZrOCl₂ feed solution to an acidic resin stationary phase (69) of a continuous annular chromatograph (34) at a first location (76) at the top (80) of said chromatograph; (c) introducing a mobile phase (69) comprising an aqueous acid to said stationary phase at a second location (78) displaced angularly from said first location; (d) rotating said annular chromatograph (34) during steps (b) and (c) to separate a zirconium product fraction (38) from other product fractions in said feed solution so that each said product fraction is angularly displaced from said first location along the length of said chromatograph; (e) collecting said zirconium product fraction (38) and further processing said zirconium product fraction to produce substantially pure zirconium metal; (f) collecting said remaining product fractions (40, 42, 44, 82) and disposing of them as required; and (g) recycling said mobile phase for reuse in step (c). The process described in claim 11, wherein said stationary phase (69) comprises a particulate acid exchange resin having an arbitrary morphology, a polydisperse to monodisperse distribution and a mean particle size of 0.01 to 500 microns. The process described in claim 11, wherein said stationary phase (69) comprises a strong acid particulate exchange resin having a spherical morphology, a monodisperse distribution and a mean particle size of 0.01 to 500 microns. The process described in claim 11, wherein said mobile phase is an aqueous acid selected from the group consisting of HCl, H₂SO₄, HNO₃, H₃PO₄ and HClO₄ and said acid has a concentration of 1 to 6 Normal. The process described in claim 14, wherein said mobile phase is HCl and has a concentration of 2 to 2.5 Normal. The process described in claim 11, wherein the concentration of said ZrOCl₂ feed solution is 10 to 300 grams per liter. The process described in claim 16, wherein said ZrOCl₂ concentration is 220 grams per liter. The process described in claim 11, wherein said other product fractions include hafnium, transition metal wastes and radioactive metal wastes. | WESTINGHOUSE ELECTRIC CORP; WESTINGHOUSE ELECTRIC CORPORATION | LEE ERNEST DEWITT; SNYDER THOMAS STEPHEN; LEE, ERNEST DEWITT; SNYDER, THOMAS STEPHEN |
EP-0490132-B1 | 490,132 | EP | B1 | EN | 19,980,708 | 1,992 | 20,100,220 | new | G02F1 | G02B5 | G02F1, G02B5 | G02F 1/1335R, G02B 5/04A | LCD Display with multifaceted back reflector | In accordance with the present invention, a transparent display (10), such as an LCD, is provided with back reflector (50) having a plurality of reflecting facets angularly displaced with respect to the plane of the display cell so as to enhance contrast of the display without consumption of additional power while reducing glare. Advantageously the reflecting facets are oriented to concentrate reflection to a viewer of light above the viewer and light coming from over the viewer's shoulder. The result of such concentration is a display having backlit visual characteristics without the consumption of backlighting power. Preferred embodiments are disclosed for vertical and horizontal mounting. | This invention relates generally to a transparent display device as set forth in claim 1. More particularly it relates to a transparent display device, such as a liquid crystal display, having a multifaceted back reflector to reduce power consumption, increase contrast and reduce glare. By transparent display, applicant refers to visual display devices wherein either the visual message portion of the display or the background portion is transparent or translucent. Examples of such displays are liquid crystal displays (LCDS) and ferroelectric light valves. The invention is particularly useful as a low power display screen for a portable computer or portable telephone.The combination of microelectronic circuits and low power liquid crystal displays has led to a wide variety of portable electronic products. These products range from electronic watches to hand-held television receivers and laptop computers. Low power consumption is a critical requirement for each of them.Despite their considerable utility in conjunction with integrated circuits, LCD displays have a number of shortcomings. In typical LCD cells the activated portion is darkened, representing a visual message, and the unactivated portion is transparent, constituting visual background. One shortcoming of LCD displays is the relatively low contrast between the activated portion and the unactivated portion. One approach to increasing the contrast is to backlight the cell, thereby producing a sharp visual contrast between the portions of the cell darkened by activation and the light shining through the transparent regions. Unfortunately, backlighting requires power. Even in so complex an electronic structure as a portable computer, the power used in display backlighting is the major drain on the system batteries.An alternative approach to increasing contrast is to provide a reflector on the back of the cell to enhance contrast by reflecting light through the transparent regions. As in the case of the backlighted cell, the reflected light enhances the visual contrast. This approach also has shortcomings. One difficulty is that both the cell and the reflector typically have parallel planar surfaces. As a consequence, light reflected from the back reflector and glare reflected from the front surface of the cell are reflected in the same direction. Moreover, the greater the amount of light that is reflected from the back reflector, the greater the amount of glare reflected from the front surface. A second difficulty is that the cell is usually thicker than a single pixel of the display. As a consequence, a shadow of darkened pixel cast onto the reflector can be confused with the real image.The document FR-A-244 957 discloses a vertically mounted opto-electronic display device that employs a reflector backplane for directing light orginating from above the device toward the eyes of a viewer. The reflector backplane includes multiple parallel strips which are angled relative to the display plane to reflect overhead light toward a viewer which would otherwise be reflected to the ground in typical vertical displays.Various efforts have been made to texture the back reflector so that reflection is essentially isotropic (sometimes referred to as Lambertian ). But because reflection is isotropic the light reflected to the viewer is necessarily diminished, and such displays lack the visual distinctiveness of a backlit display. The problem underlying the invention is to provide a transparent display device which is able to enhance the contrast of an LCD display without consuming additional power and without aggravating glare. The invention solves this problem by the features of claim 1. Preferred embodiments are defined in the dependent claims.A transparent display, such as an LCD, is provided with back reflector having a plurality of reflecting facets angularly displaced with respect to the plane of the display cell. The facets are displaced to enhance contrast of the display without consumption of additional power and to reduce glare. Advantageously the reflecting facets are oriented to concentrate reflection to a viewer of light above the viewer and light coming from over the viewer's shoulder. The result of such concentration is a display having backlit visual characteristics without the consumption of backlighting power. Preferred embodiments are disclosed for mounting on equipment in vertical and horizontal positions. In the drawings: FIG. 1is a schematic diagram of a typical transparent display having a conventional planar back reflector. The diagram is useful in illustrating the problems to which applicant's invention is directed.FIG. 2is a schematic diagram of a transparent display having a multifaceted back reflector in accordance with the invention.FIG. 3 is a schematic cross section of a transparent display having a preferred configuration back reflector for vertical mounting; and FIG. 4 is a schematic cross section of a transparent display having a preferred configuration back reflector for horizontal mounting. It is to be understood that these drawings are for purposes of illustrating the concepts of the invention and are not to scale.Referring to the drawings, FIG. 1 illustrates a problem commonly encountered with a transparent display cell 10 using a conventional planar back reflector 20 to enhance contrast. As shown, display cell 10 has a front surface 11 substantially parallel to reflector 20. As a consequence, light from source 30 is not only reflected by reflector 20 but also is reflected by front cell surface 11 as glare rays 31. Thus a viewer 40 sees not only reflected rays 32 from reflector 20 but also glare rays 31 from surface 11. Since both sets of rays are in the same direction, the orientation of the display which maximizes the reflected rays 32 also maximizes the glare rays 31.FIG. 2 schematically illustrates applicant's solution to the problem of increasing contrast while reducing glare in a transparent display. FIG. 2 is similar to FIG. 1 except planar back reflector 20 has been replaced with a multifaceted back reflector 50 having a plurality of reflecting facets angularly displaced with respect to the plane of front cell surface 11. As a consequence of this displacement, reflected rays 32 from reflector 50 are angularly displaced as compared with glare rays 31 from surface 11. Thus at appropriate viewing angle, a viewer 40 can see the contrast enhancing reflected light 32 with a reduced level of glare 31. In addition, a faceted reflector of appropriate dimensions has the additional advantage that it tends to break up shadows from dark pixels.In its more general form, the invention is a transparent display device comprising a transparent display cell having front and back sides and a multifaceted back reflector disposed adjacent the back side of the cell. The back reflector comprises at least three repeated reflecting facets angularly displaced with respect to the front side of the cell by respectively different angles. At least three facet angles are needed to ensure concentration of light in multiple reflection lobes, and the reflecting facets, while they can be randomly distributed, are preferably repeated in an array having a period of 25,4 to 1270 µm (1 to 50 mils) in order to simulate continuous back lighting and to break up pixel shadows. Preferably the facet angles are chosen to anticipate likely viewing angles and the probable location of light sources. FIG. 3 is a schematic cross section of a transparent display having a multifaceted back reflector configured for substantially vertical mounting. The display is particularly useful as the display screen for a portable computer. Specifically, the display comprises a transparent display cell 10, such as an LCD cell, having a multifaceted back reflector 50 especially designed for viewing when the display is oriented in a vertical position. The reflector 50 has a periodic repetition of plural facets (here four) 50A, SOB, 50C, and 50D, oriented to reflect to a viewer, light from a source 30A above the viewer and light from a source 30B behind the viewer in a normal position for reading. In this particular embodiment, the preferred facet angles, measured by counterclockwise rotation with respect to a line A-A' parallel to surface 11, are as follows: facet SOA is oriented at an angle of 140°, facet 50B is oriented at 10°, facet 50C, 157.5° and facet 50D, 45°. These angles can be varied within a range of ± 5° and produce a similar visual effect. The array of facets in this embodiment preferably have a period of repetition of about 10 mils.Reflector 50 is bonded to cell 10 by transparent cement 60, such as transparent silicone rubber cement. When the cell is in the vertical position, as on a computer 90, periodic facets 50A will reflect overhead light 30A substantially horizontally and periodic facets 50C will reflect reading light 30B substantially horizontally. The result can be a portable computer with substantially reduced power requirements.Reflector 50 preferably comprises a body 70 of plastic material, such as polymethyl methacrylate (PMM) coated with reflecting material 80, such as a gold colored material. The periodic structure of facets can be molded or embossed onto thermoplastics such as PMM or molded on to thermosetting plastics such as epoxy resin. Preferably the mold, in addition to providing the periodic structure, is also treated to provide a minor degree of matt finish in order to produce diffusion on the order of 10% to 20% Lambertion. This minor degree of matt finish prevents the reflection of a sharp image of light sources 30A or 30B to the viewer. After molding or embossing, the plastic is coated with the reflecting material, as by plating with gold, in accordance with techniques well known in the art.FIG. 4 is a schematic cross section of a transparent display having a preferred configuration back reflector for a substantially horizontal mounting. The display is particularly useful as the display screen for a portable telephone. Specifically, the display comprises a transparent display cell 10 having a multifaceted back reflector 51 especially designed for viewing when the display is oriented in a horizontal position. The reflector 51 has a periodic repetition of four facets 51A, 51B, 51C, and 51D, oriented to reflect to a viewer light above the viewer and light behind the viewer in a normal position for reading. Measuring the angles by clockwise rotation with respect to a line A-A' parallel to surface 11 drawn through their vertices, facet 51A is oriented at an angle of 200°, facet 51B is oriented at 0°, 51C at 225° and 51D, 140°. These angles can be varied within ± 5° and produce substantially the same visual effect.Reflector 51 can be bonded to cell 10 by transparent cement. When the cell is in the horizontal position, as on a telephone 90, periodic facets 51A will reflect overhead light at an angle of about 45° and facets 51C will reflect light over the viewer's shoulder at about 45°. Advantageously means, in the form of a plurality of threaded screws 100, are provided for fine adjustment of the facet angles. Tightening the screws pulls the plastic reflector against the back surface of cell 10, tending to flatten the faceted structure. In this case the bonding cement would be omitted. In this way a user can adjust the structure to provide optimal contrast at a desired viewing angle. Clearly this adjustment mechanism could be used with other back reflector configurations such as, for example, the configuration of Fig. 3.Preferred apparatus for making a multifaceted back reflector in accordance with the invention comprises a pair of metal calender rolls. One of the rolls has a textured surface patterned to the inverse of the periodic structure to be imprinted on the back reflector. By pressure between the rolls or a combination of heat and pressure, a sheet passing between the rolls has one surface imprinted with the desired periodic facet structure. | A transparent display device comprising: a transparent display cell (10) having front (11) and back sides,a multifaceted reflector (50) disposed adjacent the back side of said cell (10), CHARACTERIZED IN THAT said reflector (50) comprises a pattern of at least three facets displaced by respectively different angles with respect to the front side (11) of said cell (10) and repeated in a periodic array so as to reflect light from a plurality of sources to a preselected direction,wherein all facets are reflecting.A display device according to claim 1 wherein said transparent display cell (10) is an LCD cell.A display device according to claim 1 or 2 wherein the front side (11) of said transparent display cell (10) is planar and said periodic aray comprises reflecting facets oriented so that when the display is in a vertical position, said array will reflect light above and behind a viewer in a substantially horizontal direction.A display device according to claim 3 wherein the front side (11) of said transparent display cell (10) is planar and said periodic array comprises a repeated array of four reflecting facets (50A, 50B, 50C, 50D) oriented at respective angles with respect to said front side (11), of 140° ± 5°, 10° ± 5°, 157° ± 5° and 45° ± 5°.A display device according to claim 1 or 2 wherein the front side (11) of said transparent display cell (10) is planar and said periodic array comprises reflecting facets oriented so that when display is in a horizontal position, said array will reflect light above and behind a viewer at an angle of 45° ± 10°.A display device according to claim 5 wherein the front side (11) of said transparent display cell (10) is planar and said periodic array comprises a repeated array of four reflecting facets oriented at respective angles with respect to said front side, of 200° ± 5°, 0° ± 5°, 225° ± 5° and 140° ± 5°.A display device according to any one of claims 1 to 6 wherein the period of repetition of said array is in the range from 25.4 to 1270 µm (1 to 50 mils).A display device according to claims 1-7 wherein said reflecting facets are textured to provide diffusion of 10 to 20 % Lambertian.A display device according to claims 1-7 wherein said reflecting facets comprise gold-colored reflecting layers.A computer comprising a display device according to claims 1-7.A telephone comprising a display device according to claims 1-7.A display device according to claims 1-7 further comprising means (100) for adjusting the angles of said facets. | AT & T CORP; AT&T CORP. | BLONDER GREG E; BLONDER, GREG E. |
EP-0490134-B1 | 490,134 | EP | B1 | EN | 19,960,529 | 1,992 | 20,100,220 | new | C08C19 | null | C08F8, C08C19 | C08C 19/02 | Amine modified hydrogenation of nitrile rubber | An improved process is provided for the hydrogenation of nitrile rubber wherein the molecular weight increase during the hydrogenation process is minimized and controlled, the improvement being that the hydrogenation is undertaken in the presence in the solution of an NH₂-containing compound selected from ammonia and a C₁ to C₂₀ primary amine. | An improved process is provided for the hydrogenation of nitrile rubber wherein the molecular weight increase during the hydrogenation process is minimized and controlled, the improvement being that the hydrogenation is undertaken in the presence in the solution of an NH₂-containing compound selected from ammonia and a C₁ to C₂₀ primary amine. FIELD OF THE INVENTIONThe present invention relates to an improved process for the production of hydrogenated nitrile rubber. BACKGROUND OF THE INVENTIONIt is well known that the carbon-carbon double bonds in polymers may be hydrogenated by treatment of the polymer with hydrogen in the presence of a number of catalysts. It is also well known that the carbon-carbon double bonds in a nitrile rubber, the nitrile rubber being a polymer comprising a C₄-C₆ conjugated diolefin and a C₃-C₅ unsaturated nitrile, can be selectively hydrogenated, without significant hydrogenation of the C=N bonds, by treatment of the polymer with hydrogen in the presence of selected catalysts - for example, British Patent 1,558,491; U.S. Patents 3,700,637; 4,384,081; 4,464,515 and 4,503,196. The use of ruthenium catalysts for the hydrogenation of nitrile rubbers is described in U.S. Patents 4,631,315; 4,816,525 and 4,812,528. In the hydrogenation of nitrile rubbers, it has been found that the molecular weight of the polymer, as indicated by the measured intrinsic viscosity or the Mooney viscosity, increases--this molecular weight increase is believed to be due to a low level of interaction occurring between two or more polymer molecules. The increase in molecular weight varies with the nature of the catalyst, the solvent used in the hydrogenation process and the reaction conditions used for the hydrogenation. The molecular weight increase is particularly noticeable when certain of the ruthenium catalysts are used and, in fact, under certain conditions the interaction between polymer molecules can be such that the hydrogenated polymer contains gelled (crosslinked) or insoluble polymer. Although a slight increase in molecular weight can be tolerated, if the molecular weight of the hydrogenated polymer is too high this causes it to be of low acceptability by the manufacturer of the products, such as hoses, gaskets, etc., because it is difficult to handle such high molecular weight polymers on conventional equipment. Accordingly, the present invention is directed to an improved process wherein the molecular weight increase in the hydrogenation process is minimized and controlled. SUMMARY OF THE INVENTIONThe present invention provides an improved process for the production of hydrogenated nitrile rubber wherein a nitrile rubber which is a polymer comprising a conjugated C₄-C₆ diolefin and a C₃-C₅ unsaturated nitrile is hydrogenated while in solution in the presence of a divalent ruthenium catalyst selected from compounds of the general formula RuXY(CO)ZL₂, or RuDE(CO)Mn,or RuGJM₃ or RuK₂N₂ wherein X is selected from a halogen atom or a carboxylate group, Y is selected from a halogen atom, a hydrogen atom, a phenyl group, a carboxylate group or a phenylvinyl group, Z is selected from CO, pyridine, benzonitrile or no ligand and L is selected from the phosphine ligands of the general formula PR₃ in which R is selected from alicyclic or alkyl groups, n is 2 or 3 and when n is 3 D is a halogen atom and E is a hydrogen atom and when n is 2 D is selected from a halogen atom or a carboxylate group, E is selected from a halogen atom, a hydrogen atom, a phenyl group or a carboxylate group, and M is selected from the phosphine ligands of the formula PA₃ in which A is a phenyl group or a C₁ to C₄ alkyl group or mixtures thereof, G is selected from a halogen atom or a hydrogen atom, J is selected from a halogen atom or a carboxylate group, K is a carboxylate group and N is triphenylphosphine, the improvement being that the hydrogenation is undertaken in the presence of an NH₂-containing compound selected from ammonia and a C₁ to C₂₀ primary amine in the solution. DETAILED DESCRIPTIONThe nitrile rubber which is hydrogenated in the process of this invention is a polymer comprising a conjugated C₄-C₆ diolefin and a C₃-C₅ unsaturated nitrile. The conjugated C₄-C₆ diolefin is selected from butadiene, isoprene, piperylene and 2,3-dimethyl butadiene, with butadiene and isoprene being preferred and butadiene being most preferred. The conjugated diolefin forms from about 50 to about 85 per cent by weight of the polymer. The C₃-C₅ unsaturated nitrile is selected from acrylonitrile, methacrylonitrile and ethacrylonitrile, with acrylonitrile being most preferred and forms from 15 to 50 per cent by weight of the polymer. The polymer may also contain a small amount, that is from 1 to 10 per cent by weight of the polymer, of an unsaturated carboxylic acid selected from fumaric acid, maleic acid, acrylic acid and methacrylic acid and the conjugated diolefin forms from 40 to 84 per cent by weight of the polymer. The nitrile rubber has a molecular weight, as expressed by the Mooney viscosity (ML 1+4 at 100°C) of from 25 to 70. A preferred nitrile rubber is a butadiene-acrylonitrile polymer having an acrylonitrile content of from about 25 to about 45 per cent by weight and having a Mooney viscosity (ML 1+4 at 100°C) of from 25 to 60. Suitable solvents for the hydrogenation process include the aryl compounds such as benzene, toluene, xylene, monochlorobenzene and dichlorobenzene, with monochlorobenzene being most preferred, aliphatic ethers such as tetrahydrofuran and dioxane, and aliphatic ketones such as methyl ethyl ketone, or mixtures of solvents such as monochlorobenzene and methyl ethyl ketone. Hydrogen is provided as essentially pure dry gas at a pressure of from 25 kg/cm² (355 psi) to 100 kg/cm² (1420 psi). The hydrogenation reaction is undertaken in a suitable reaction vessel equipped with a temperature regulating means and an agitator. The polymer solution is added to the reaction vessel, any necessary degassing is undertaken, and either the catalyst, pure or in solution, is added followed by pressurizing with hydrogen or the vessel is pressurized with hydrogen and the catalyst, pure or in solution, is added. The reactor is heated to the desired temperature at a suitable point following the addition of the polymer solution. Temperatures for the hydrogenation are from 80° to 200°C, preferably from 100°C to 155°C. Hydrogen may be added to the reactor during the hydrogenation and the reaction is complete within 2 to 24 hours, although when the preferred catalysts are used the reaction time is from 2 to 8 hours. The degree of hydrogenation may be controlled by control of one or more of the reaction time, temperature or hydrogen pressure, preferably reaction time. On completion of the reaction, the reaction vessel is vented and the polymer recovered by contact with hot water/steam or an alcohol followed by drying. The divalent ruthenium catalyst used in the process is selected from compounds of the general formula RuXY(CO)ZL₂, or RuDE(CO)Mn,or RuGJM₃ or RuK₂N₂ wherein X is selected from a halogen atom or a carboxylate group, preferably is a halogen atom and most preferably is chlorine; Y is selected from a halogen atom, a hydrogen atom, a phenyl group, a carboxylate group or a phenylvinyl group, preferably is a chlorine atom or a hydrogen atom and most preferably is a hydrogen atom; Z is selected from CO, pyridine, benzonitrile or no ligand; L is selected from phosphine ligands of the general formula PR₃ wherein R is selected from alicyclic or alkyl groups. A preferred alicyclic group is cyclohexyl. The alkyl group is preferably selected from isopropyl, tertiary butyl and secondary butyl. Preferably R is cyclohexyl. n is 2 or 3 and when n is 3 D is a halogen atom and E is a hydrogen atom and when n is 2 D is selected from a halogen atom or a carboxylate group; E is selected from a halogen atom, a hydrogen atom, a phenyl group or a carboxylate group, preferably a halogen atom or a hydrogen atom; M is selected from the phosphine ligands of formula PA₃ in which A is a phenyl group or a C₁ to C₄ alkyl group or mixtures thereof; G is selected from a halogen atom or a hydrogen atom; J is selected from a halogen atom or a carboxylate group; K is a carboxylate group and N is triphenylphosphine. Specific examples of suitable divalent ruthenium catalysts include carbonylchlorohydrido bis (tricyclohexylphosphine) ruthenium (II), carbonylchlorohydrido bis (trisopropylphosphine) ruthenium (II), carbonylchloro benzoato bis(triphenylphosphine) ruthenium (II), carbonylchlorohydrido tris (triphenylphosphine) ruthenium (II), and dichloro tris (triphenylphosphine) ruthenium (II). The concentration of the ruthenium catalyst in the solution is not critical and usually is within the range of from about 0.015 to about 2 per cent by weight of the nitrile rubber. For economic reasons it is desirable to minimize the concentration of the ruthenium catalyst and accordingly it is preferably used within the range of from about 0.015 to about 0.15 per cent by weight of the nitrile rubber. The improved process of this invention requires the presence, during the hydrogenation, of an NH₂-containing compound selected from ammonia and a C₁ to C₂₀ primary amine. The NH₂-containing compound is present in the solution during the hydrogenation process--that is to say, it can be added to the reactants at any convenient stage before the hydrogenation reaction is initiated. When the NH₂-containing compound is ammonia it is used as the essentially dry, essentially pure material, either gaseous or liquid although gaseous is preferred for control purposes. Suitable primary amines are selected from the primary amines of the formula R-NH₂ where R is selected from C₁ to C₂₀ alkyl groups which may be linear or branched, C₆ to C₁₂ alicyclic groups, C₆ to C₉ aryl groups, C₇ to C₁₀ aralkyl groups and fused ring groups such as adamantane. Examples of suitable amines include compounds where R is methyl, ethyl, n-butyl, sec-butyl, tert-butyl, amyl, iso-amyl, octyl, dodecyl, tetradecyl, octadecyl and mixtures thereof, cyclohexyl and cyclooctyl, phenyl and tolyl, and benzyl and methyl substituted benzyl. Preferred primary amines include the C₄ to C₂₀ alkyl primary amines and cyclohexylamine present at a concentration of from 0.4 to 1 parts by weight per 100 parts by weight of nitrile rubber. The concentration in the reactor of the ammonia is from 0.1 to 0.3, preferably from 0.15 to 0.25 parts by weight per 100 parts by weight of nitrile rubber and of the primary amine is from 0.2 to 3, preferably from 0.4 to 1, parts by weight per 100 parts by weight of nitrile rubber. The presence of the NH₂-containing compound during the hydrogenation process leads to the production of a hydrogenated nitrile rubber which has an acceptably small increase in the molecular weight compared to that of the original nitrile rubber. The molecular weight may be measured as the Mooney viscosity determined at 125°C (ML 1+4 at 125°C) or as the intrinsic viscosity determined at 35°C in monochlorbenzene. In the absence of the NH₂-containing compound or in the presence of a secondary or tertiary amine the hydrogenation process yields a polymer having a significantly increased molecular weight compared to the molecular weight of the original nitrile rubber. The following examples illustrate the scope of the invention and are not intended to limit the same. EXAMPLESExample 1A 300 ml glass lined stainless steel autoclave equipped with temperature control means, an agitator and solution and hydrogen gas addition points was used. A butadiene-acrylonitrile nitrile rubber having a bound acrylonitrile content of about 38 weight per cent and a Mooney viscosity (ML 1+4 at 125°C) of about 29 was used at a concentration of about 9.3 weight per cent in chlorobenzene. The catalyst used was carbonylchlorohydrido bis (tricyclohexylphosphine) ruthenium (II) at a concentration in the reactor of about 0.05 weight per cent based on the nitrile rubber. Hydrogen was added to the reactor to a total pressure of about 56.3 kg/cm² (800 psi). The amine of the type and in the quantity shown in Table I was added to the reactor. The reaction temperature was about 145°C. The reaction time was between 4 and 8 hours. The results in Table I clearly show that primary amines do not significantly interfere with the hydrogenation reaction and that the hydrogenated nitrile rubber has not significantly increased in molecular weight, as shown by the intrinsic viscosity, compared to when no amine or when secondary or tertiary amines are used. An intrinsic viscosity of about 1.5 approximately corresponds to a Mooney viscosity (ML 1+4 at 125°C) of about 55 and an intrinsic viscosity of about 1.9 approximately corresponds to a Mooney viscosity of about 100. Exp't. No. Amine Type Amine Conc. Reaction Time % Hydrog. Intrinsic Viscosity 1--499+1.93 2A0.39599+1.66 3A0.78699+1.56 4A1.17799+1.51 5B0.6699+1.56 6C0.78981.48 7D0.77699+1.78 8E0.73499+1.93 Notes: Amine Type A = octylamine, B = hexylamine, C = n-butylamine, D - di-butylamine, E - triethylamine Amine Conc.Concentration of amine, weight per cent based on nitrile rubber. % Hydrog.Per cent hydrogenation of C=C bonds in nitrile rubber, determined by infra-red spectroscopy and ¹H NMR spectroscopy. Intrinsic ViscosityMeasured at 35°C in chlorobenzene using the Ubbelohde method; shown as dL/g. Example 2The equipment and procedure was the same as that used in Example 1. In this example the amines used were (Amine Type F) cyclohexylamine and (Amine Type G) morpholine and the results are shown in Table II. Exp't. No. Amine Type Amine Conc. Reaction Time % Hydrog. Intrinsic Viscosity 10--499+1.93 11F0.85699+1.50 12F0.6699+1.58 13G0.6499+2.03 The results show that the molecular weight of the polymer is not significantly increased in the presence of the primary amine during the hydrogenation reaction. Example 3 A two gallon reactor was used. The nitrile rubber was the same as that used in Example 1 and was used as a 9.3 per cent solution in chlorobenzene. The same catalyst as in Example 1 was used at a concentration of about 0.07 weight per cent based on nitrile rubber. Hydrogen was added to a pressure of about 84.5 kg/cm² (1200 psi). The amine used was dodecylamine. The reaction temperature was 145°C. The results are shown in Table III with the molecular weight being shown as the Mooney viscosity (ML 1+4 at 125°C) for polymer samples recovered by contact with steam/hot water and subsequently dried. Exp't. No. Amine Conc. Reaction Time % Hydrog. Mooney Viscosity 20 0.78 599.5+49.5 2114.599.5+50 221.5599.5+50 232599.348.5 240.4499.5+71 250.1699.5+93 260499.5+100 Example 4Using the procedure and nitrile rubber described in Example 1 except that the nitrile rubber concentration was 3 weight per cent, additional catalyst systems were studied. The primary amine used was cyclohexylamine at a concentration of 3 weight per cent based on the nitrile rubber in Experiments 31, 32 and 33, Experiment 30 being a control with no added amine. The solvent was monochlorobenzene, the reaction temperature was 140°C and the hydrogen pressure was 42.2 kg/cm² for Experiments 30, 31 and 32 and 56.3 kg/cm² for Experiment 33. The catalysts used were for Experiments 30 and 31 carbonylchloro benzoato bis(triphenylphosphine) ruthenium II, for Experiment 32 carbonylchlorohydrido tris(triphenylphosphine) ruthenium II and for Experiment 33 dichloro tris(triphenylphosphine) phosphine) ruthenium II. The results are shown in Table IV. Exp't. No. Catalyst Conc. Reaction Time % Hydrog. Intrinsic Viscosity 300.50.25ndnd 310.51096.51.79 320.62089.5nd 330.52292nd In Experiment 30, the product was a gelled mass. For Experiments 32 and 33, the intrinsic viscosities were not determined but are believed to be of a similar order to that for Experiment 31. Example 5Using the procedure described in Example 1, additional amines were tested. The materials and conditions used were as described and the results are shown in Table V. Exp't. No. Amine Type Amine Conc. Reaction Time % Hydrog. Intrinsic Viscosity 40H0.35599+1.62 41H0.7797.21.46 42I0.7699+1.59 43J0.75699+1.58 44K0.373.599+1.73 45K0.75599+1.52 Amine Type - H = aniline, I = benzylamine, J - isoamylamine, K - tert-butylamine Example 6Using the procedure and conditions described in Example 3, further amines were tested with the results shown in Table VI. Exp't. No. Amine Type Amine Conc. Reaction Time % Hydrog. Mooney Viscosity 50L0.788.599.364 51M0.78299.5+66 Amine Type - L =stearyl amine product, commercially available as Kemamine P-900D, believed to contain about 5% C₁₆ amine, about 93% stearylamine and about 2% C₂₀ amine. M =hydrogenated tallow amine, commercially available as Kemamine P-970D, believed to contain about 5% C₁₄ amine, 30% C₁₆ amine, about 65% stearylamine. Example 7Using the materials and procedure described in Example 1, ammonia was used as the NH₂-containing compound. After the reactor and contents had been purged with hydrogen, ammonia was added to a concentration of 0.19 weight per cent based on the nitrile rubber. The results are shown in Table VII from which it is clear that ammonia does not significantly interfere with the hydrogenation reaction and that the hydrogenated nitrile rubber has not significantly increased in molecular weight. Exp't No. Reaction Time % Hydrog. Intrinsic Viscosity 606.599.11.58 61799.21.53 | An improved process for the production of hydrogenated nitrile rubber wherein a nitrile rubber which is a polymer comprising a conjugated C₄-C₆ diolefin and a C₃-C₅ unsaturated nitrile is hydrogenated while in solution in the presence of a divalent ruthenium catalyst selected from compounds of the general formula RuXY(CO)ZL₂, or RuDE(CO)Mn,or RuGJM₃, or RuK₂N₂ wherein X is selected from a halogen atom or a carboxylate group, Y is selected from a halogen atom, a hydrogen atom, a phenyl group, a carboxylate group or a phenylvinyl group, Z is selected from CO, pyridine, benzonitrile or no ligand and L is selected from the phosphine ligands of the general formula PR₃ in which R is selected from alicyclic or alkyl groups, n is selected from 2 or 3 and when n is 3 D is a halogen atom and E is a hydrogen atom and when n is 2 D is selected from a halogen atom or a carboxylate group, E is selected from a halogen atom, a hydrogen atom, a phenyl group or a carboxylate group and M is selected from the phosphine ligands of the formula PA₃ in which A is a phenyl group or a C₁ to C₄ alkyl group or mixtures thereof, G is selected from a halogen atom or a hydrogen atom, J is selected from a halogen atom or a carboxylate group, K is a carboxylate group and N is triphenylphosphine, the improvement being that the hydrogenation is undertaken in the presence of an NH₂-containing compound selected from ammonia and a C₁ to C₂₀ primary amine. The process of Claim 1 wherein the NH₂-containing compound is a primary amine selected-from the C₁ to C₂₀ alkyl primary amines, the C₆ to C₁₂ alicyclic primary amines, the C₆ to C₉ aryl primary amines and the C₇ to C₁₀ aralkyl primary amines. The process of Claim 1 wherein the NH₂-containing compound is ammonia. The process of Claim 1 wherein the NH₂-containing compound is ammonia present at a concentration of from 0.1 to 0.3 parts by weight per 100 parts by weight of the nitrile rubber, or wherein the primary amine is a C₄ to C₁₂ alkyl primary amine present at a concentration of from 0.4 to 1 parts by weight per 100 parts by weight of the nitrile rubber. The process of Claim 2 wherein the primary amine is cyclohexylamine present at a concentration of from 0.4 to 1 parts by weight per 100 parts by weight of the nitrile rubber. The process of Claim 1 wherein the nitrile rubber is in solution in a solvent selected from benzene, toluene, xylene, chlorobenzene and dichlorobenzene and the hydrogen pressure is from 25 to 100 kg/cm². The process of Claim 1 wherein the divalent ruthenium catalyst is selected from carbonylchlorohydrido tris (triphenylphosphine) ruthenium II , dichloro tris (triphenylphosphine) ruthenium II, carbonylchlorohydrido bis (tricyclohexylphosphine) ruthenium II and carbonylchlorohydrido bis (triisopropylphosphine) ruthenium II. The process of Claim 7 wherein the NH₂-containing compound is ammonia and is present at a concentration of from 0.15 to 0.25 parts by weight per 100 parts by weight of nitrile rubber. The process of Claim 1 wherein the nitrile rubber is a polymer containing from 50 to 85 weight per cent of butadiene or isoprene and from 15 to 50 weight per cent of acrylonitrile. The process of Claim 1 wherein the nitrile rubber is a polymer containing from 40 to 84 weight per cent of butadiene, from 15 to 50 weight per cent of acrylonitrile and from 1 to 10 weight per cent of an unsaturated carboxylic acid selected from fumaric acid, maleic acid, acrylic acid and methacrylic acid. | BAYER RUBBER INC; BAYER RUBBER INC. | MCMANUS NEIL THOMAS; REMPEL GARRY LLEWELLYN; MCMANUS, NEIL THOMAS; REMPEL, GARRY LLEWELLYN |
EP-0490138-B1 | 490,138 | EP | B1 | EN | 19,970,129 | 1,992 | 20,100,220 | new | G11B15 | G11B15 | G11B27, G11B15, G11B31, G11B5 | S11B27:024, G11B 27/028, G11B 27/10, G11B 15/00, G11B 15/18B3, G11B 15/087, G11B 31/00, G11B 27/00A | Apparatus for dubbing a recorded video tape in synchronism with the playing of the video tape | An apparatus for dubbing a recorded video tape simultaneously with the playing back of the video tape from the very beginning of the playing back comprising, a synchronous record switch means for generating a synchronous record signal to enable the video tape recorder to dub the video tape in synchronism with the playing back, a control means for generating a first and second control signals, the first control signal driving the deck means in record mode so as to load an empty video tape and thereafter to pause the video tape recorder when a record key signal is inputted together with the synchronous record signal, the second signal driving the deck means in playback mode so as to load a recorded video tape and thereafter to let the video tape recorder be in still mode when a playback key signal is inputted together with the synchronous record signal, a pilot signal generating means for generating a pilot signal of a given frequency in response to the first or second signal, a signal mixer for mixing the pilot signal and an audio signal generated from the recorded video tape being played back, a pilot signal detection means for detecting the pilot signal for detecting the pilot signal from the output signal of the signal mixer, an integrating circuit for integrating the pilot signal, and a comparator for comparing the integrated signal of the integrating circuit with a reference signal so as to detect the pilot signal in order to release the video tape recorder from the pause or still mode. | The present invention relates to a video tape recorder, and more particularly to a method for copying a program recorded in a video tape by using two video tape recorders. Generally, a double deck audio cassette tape recorder has a record/playback deck together with an exclusive playback deck. In this case, a recorded cassette tape is loaded in the exclusive playback deck and the pause and playback buttons are pressed, whereas an empty cassette tape is loaded in the record/playback deck and the record button is pressed. Then the record/playback deck is operated in a record mode, while the exclusive playback deck is changed from a pause mode to a playback mode, so that the dubbing operation is performed. However, a video tape recorder occupies too large volume to be provided with two decks. Accordingly a recorded video tape is dubbed by using two video tape recorders, thus making it complicated to perform a precise dubbing. For example, one video tape recorder is operated in the playback mode, and the other in the record mode by using both hands of a user. In this case, if the playback mode of the one video tape recorder starts prior to the record mode of the other video tape recorder, the beginning of the recorded video tape is partially not dubbed. JP-A-61080582 discloses an apparatus for dubbing a recorded video tape under the control of a remote controller. Two video tape recorders are connected together to provide only the video and sound signals from one recorder to the other. One of the video tape recorders then acts as a playback means and the other is a recording means. The playback means performs a tape loading operation, a pause operation and a playback operation under the control of signals produced by the remote controller. At the same time the recording is controlled by the remote controller to perform a tape loading operation, a pause operation and a recording operation. The apparatus of document D1 has a disadvantage that the dubbing operation is controlled entirely by the remote controller with no feedback to the remote controller or communication between the two video tape recorders. Consequently, the dubbing operation may be started unsuccessfully if any of the signals from the remote controller do not reach the video tape recorders or if either of the video tape recorders are not ready for operation. It is the object of the invention to provide an apparatus and method for subbing a video tape in a more reliable manner and with greater ease of operation. This object is solved by the subject matter of claims 1 and 3. Preferred embodiments are the subject matter of claims dependent on claims 1 and 3. The present invention will now be described more specifically with reference to the drawings attached only by way of example. BRIEF DESCRIPTION OF THE ATTACHED DRAWINGSFor a better understanding of the invention and to show how the same may be carried into effect, reference will now be made, by way of example, to the accompanying diagrammatic drawings, in which: FIG. 1 is a block diagram for illustrating the inventive apparatus; FIG. 2 is a block diagram for illustrating two inventive apparatuses of FIG. 1 being connected to perform the simultaneous dubbing; FIG. 3 is a block diagram for illustrating in more detail the structure of the inventive apparatus of Fig. 1; FIG. 4 is a block diagram for illustrating two inventive apparatuses of Fig. 3 being connected to perform the simultaneous dubbing; and FIG. 5 is a flow chart for illustrating the steps of the inventive method for performing the simultaneous dubbing. DETAILED DESCRIPTION OF CERTAIN PREFERRED EMBODIMENTSReferring to FIG. 1, a mode selection key means 1 is to generate the signals for operating a video tape recorder in the playback and record modes. The system controller 3 controls a deck mechanism 4 and control circuit 5 in response to the signals generated by the mode selection key means 1 and a synchronous record switch 2. If the record switch (not shown) of the mode selection key means 1 is turned on together with the synchronous record switch 2, the system controller 3 causes an empty video tape to be loaded into the deck, and then the deck to be in the pause mode. Thereafter the system controller 3 provides a control signal to a pilot signal generating means 6 to generate a pilot signal of a given frequency applied through an audio processing means 7 to the audio line output terminal (Aout), which pilot signal is in turn applied to the audio line input terminal of another video tape recorder. Thereafter, the pilot signal is fed back from the another video tape recorder to the audio line input terminal (Ain), and detected by the audio processing means 7 to transmit it to the system controller 3. Then the system controller 3 changes the operational mode of the deck 4 from the pause mode to the record mode. Thus the normal record function is performed. Meanwhile, the video processing means 8 processes the video signal of the another video tape recorder supplied with through the video line input terminal (Vin). The processed video signal is transmitted to the record head to record it in an empty video tape (not shown). Alternatively with assuming the apparatus of FIG. 1 is a video tape recorder for playing back a recorded video tape, if the playback switch of the mode selection key means 1 is turned on together with the synchronous record switch 2, the system controller 3 controls the control circuit 5 so as to cause the recorded video tape to be loaded in the deck 4, and then the deck to be in the still mode. Thereafter, if a pilot signal is inputted through the audio line input terminal (Ain), the system controller 3 changes the operational mode of the deck from the still mode to the playback mode. Meanwhile, the video processing means 8 processes the video tape signals read by the playback head (not shown). The processed video tape signals are transmitted through the video line output terminals (Vout) to another video tape recorder in the record mode. Referring to FIG. 2, it is assumed the upper dotted rectangle is a first video tape recorder operated in the playback mode, and the lower dotted rectangle a second video tape recorder operated in the record mode. The audio line input and output terminals (Ain and Aout) of the first video tape recorder are connected respectively to the audio line output and input terminals (Aout and Ain) of the second video tape recorder. Also the video line output terminal (Vout) of the first video tape recorder is connected to the video line input terminal (Vin) of the second video tape recorder. In operation, if the synchronous record switches 2A and 2B of the first and second video tape recorders are turned on, the system controller 3A and 3B recognize the synchronous record mode being presently performed. Then if the playback key of the mode selection key means 1A is pressed, the system controller 3A controls the control circuit 5A so as to load a recorded video tape (not shown) to play back in the deck 4A, and then to stop the rotation of the capstan (not shown) of the first video tape recorder. Thus the system controller 3A causes the first video tape recorder to be in the still mode until receiving from the audio signal processing means 7A a pilot signal generated by the second video tape recorder as described hereinafter. Meanwhile, if the record key of the mode selection key means 1B of the second video tape recorder is pressed, the system controller 3B controls the control circuit 5B so as to load an empty video tape (not shown) in the deck 4B, and then to stop the rotation of the capstan (not shown) of the second video tape recorder, thus letting the deck 4B in the pause mode. In addition, the system controller 3B provides a control signal to the pilot signal generating means 6B to generate a pilot signal applied through the audio processing means 7B to the audio line output terminal (Aout) to the audio line input terminal (Ain) of the first video tape recorder. The inputted pilot signal is applied through the audio processing means 7A to the system controller 3A to change the operational mode of the first video tape recorder from the still mode to the playback mode. Then the system controller 3A of the first video tape recorder provides a control signal to the pilot signal generating means 6A to generate a pilot signal applied to the audio processing means 7A. The audio processing means 7A mixes the pilot signal with the audio signals of the recorded video tape generated from the audio head. The mixed signals are applied through the audio output terminal (Aout) of the first video tape recorder to the audio input terminal (Ain) of the second video tape recorder to the audio processing means 7B. The audio processing means 7B detects the pilot signal applied to the system controller 3B of the second video tape recorder. Then the system controller 3B controls the control circuit 5B so as to change the operational mode of the deck 4B from the pause mode into the record mode. Thus the second video tape recorder performs the recording function simultaneously with the playing back of the first video tape recorder from the very beginning of the playing back. Now reference is made to FIG. 3 for detailedly illustrating the apparatus of FIG. 1. With assuming this apparatus is in the record mode, the system controller 3 generates a control signal of high state applied through the first control terminal C1 to a resistor 60 to the base of a transistor 61. Then the transistor 61 is turned on so as to enable a sine wave signal generator 62 by a voltage B+. The sine wave signal generator 62 provides a signal of a suitable oscillation frequency (e.g., 1KHz - 3KHz) to a frequency multiplier 63. The output signal of the frequency multiplier 63 is applied to a mixer 64. In this case, it is desired that the frequency-multiplied signal have an inaudible frequency not so as to interfere with the audio signal generated from the audio processing means 7, thus preventing the multiplied frequency being recorded on the video tape by the audio head. The frequency-multiplied signal is transmitted through the mixer 64 to the audio line output terminal (Aout) to the audio line input terminal of another video tape recorder. Meanwhile, if another frequency-multiplied signal of an external source is inputted through the audio line input terminal (Ain), the audio processing means 7 provides the played back audio signal together with the frequency-multiplied signal (pilot signal) through the mixer 64 to the audio line output terminal to a monitor. In addition, the output of the mixer 64 is transmitted through an analog switch 65 controlled by the second control signal C2 of the system controller 3 to a band pass filter 66. The second control signal C2 of the system controller 3 is to detect the pilot signal after the completion of the tape loading. The band pass filter 66 detects the pilot signal from the mixed signal of the audio signal and pilot signal received through the analog switch 65, which pilot signal is applied to an integrating circuit 67. The integrating circuit 67 integrates the pilot signal into a direct current signal applied to a comparator 68, which compares the integrated direct current signal with a given reference signal so as to detect the pilot signal. If there is detected the pilot signal, the comparator 68 generates a signal of high state that is supplied to the system controller 3 as a control signal C3. Then the system controller 3 changes the operational mode of the deck from the pause mode to the record mode. Alternatively, if the video tape recorder of FIG. 3 is to serve the playback mode, the system controller 3, after performing the still mode, turns on the analog switch 65 so as to receive the pilot signal from the audio line input terminal (Ain) through the audio processing means 7 and the mixer 64. Then, the band pass filter 66 detects the pilot signal applied to the integrating circuit 67, which integrates the pilot signal into a direct current signal applied to the comparator 68. As a result, the comparator 68 provides a signal of high state to the system controller 3. Thus the system controller 3 changes the operational mode of the deck from the still mode to the normal playback mode. Meanwhile, the video processing means 8 processes the recorded signal of the video tape retrieved by the video playback head. The processed signal is supplied through the video line output terminal (Vout) to the other video tape recorder serving the record mode, while the audio signal retrieved by the audio playback head is supplied through the audio line output terminal (Aout) to the other video tape recorder. Thus the simultaneous dubbing is performed. Referring to FIG. 4 for more specifically illustrating two apparatuses of FIG. 3 connected similar to FIG. 2, it is assumed that the left part of the dotted lines is a first video tape recorder for serving the playback mode, and the right part is a second video tape recorder for serving the record mode. Of course, the audio and video line input/output terminals of the video tape recorder are connected as shown in FIG. 2. In operation, the synchronous record switches 2A and 2B of the first and second video tape recorders are pressed, the system controller 3A and 3B recognizes the simultaneous dubbing mode. Then the playback key of the first video tape recorder is pressed so as to cause the system controller 3A to control the control circuit 5A to load a recorded video tape into the deck 4A, and thereafter to stop the rotation of the capstan so as to cause the first video tape recorder to be in the still mode. Meanwhile, the record key of the mode selection key means 1B of the second video tape recorder is pressed so as to cause the system controller 3B to control the control circuit 5B to load an empty video tape into the deck 4B, and thereafter to let the second video tape recorder be in the pause mode. The system controller 3B also turns on the transistor 61B through the resistor 60B. Then the sine wave signal generator 62 applies a given sine wave signal to the frequency multiplier 63B. The frequency-multiplied signal is applied through the mixer 64B to the audio line output terminal to the audio line input terminal (Ain) of the first video tape recorder, and to the audio processing means 7A. The audio processing means 7A applies the frequency-multiplied signal, i.e., the pilot signal received from the second video tape recorder to the mixer 64A. The output signal of the mixer 64A is detected by the band pass filter 66A applied to the integrating circuit 67A, since the analog switch 65A is turned on the system controller 3A after the completion of the tape loading of the first video tape recorder. The integrating circuit 67A integrates the detected signal into a direct current signal applied to the comparator 68A, which in turn applies the pilot signal to the system controller 3A. Thus, the system controller 3A recognizes the control signal C3 of high state so as to cause the control circuit 5A to change the operational mode the deck 4A from the still mode to the playback mode. Consequently, the audio signal and the pilot signal retrieved by the audio playback head is processed by the audio processing means 7A applied through the audio line output terminal (Aout) to the audio line input terminal (Ain) of the second video tape recorder to the audio processing means 7B of the second video tape recorder. The audio and pilot signals of the audio processing means 7B are applied through the mixer 64B to the analog switch 65B to the band pass filter 66B, which detects only the pilot signal applied to the integrating circuit 67B. Then the integrating circuit 67B integrates the pilot signal applied to the comparator 68B, which in turn provides a signal of high state to the system controller 3B. Then the system controller 3B changes the operational mode of the deck of the second video tape recorder to the record mode. Thus the recording function of the second video tape recorder is performed from the very beginning of the playback function of the first video tape recorder. Of course, the audio and video playback signals of the first video tape recorder are retrieved by the audio and video playback head applied to the monitor, and recorded in the empty video tape by the audio and video record head of the second video tape recorder. Referring to FIG. 5 for illustrating the flow chart of performing the simultaneous dubbing according to the present invention, the system controller 3A and 3B determine whether the synchronous keys 2A and 2B of the first and second video tape recorders are pressed in step 101. If All the synchronous keys 2A and 2B are not pressed, the program proceeds to the step 102 for each performing independent function. However, if all the synchronous record keys 2A and 2B are pressed, the program proceeds to step 103 with the playback key of the first video tape recorder being pressed earlier than the record key of the second video tape recorder. Then the system controller 3A loads the recorded video tape into the deck in step 104, and lets the first video tape recorder be in the still mode after the completion of the loading. Further, the system controller 3A turns on the analog switch by the control signal C2 of high state, and checks the control signal C3 in step 106. Meanwhile, if the record switch of the second video tape recorder is pressed, the program proceeds from step 107 to step 108, so that the system controller 3B of the second video tape recorder loads an empty video tape, and checks whether the loading is completed in step 109. If the loading is completed, the system controller 3B lets the second video tape recorder be in the pause mode, and generates the pilot signal by making the control signal C1 high. The pilot signal is supplied to the first video tape recorder. The system controller 3B also makes the control signal C2 high in order to turn on the analog switch 65B, and checks the state of the control signal C3. If the pilot signal generated from the second video tape recorder is applied to the first video tape recorder, the system controller 3A determines whether the control signal C3 is high, in step 111. If the control signal C3 is high to indicate the existence of the pilot signal, the system controller 3A changes the operational mode of the first video tape recorder from the still mode to the record mode, while making the control signal C1 high so as to generate the pilot signal applied to the second video tape recorder, in step 112. In this case, the system controller 3B determines whether the control signal C3 is high, thus checking the existence of the pilot signal. If the control signal C3 is high in step 113, the program proceeds to step 114, so that the system controller 3B changes the operational mode of the second video tape recorder from the pause mode to the normal record mode in step 115. Finally, the record/playback function of the first and second video tape recorders is completed in step 116. As stated above, the present invention employs a pilot signal in order to dub a recorded video tape from the very beginning of the playing back thereof by using two video tape recorders. | Video tape recorder comprising a mode selection key means (1) for generating a plurality of key signals so as to perform various functions including record and playback functions, a deck means (4) for playing back or recording a video tape in response to said key signals, and dubbing means for dubbing a recorded video tape simultaneously with the playing back of the video tape from the very beginning of said playing back, said dubbing means comprising: a synchronous record switch means (2) for generating a synchronous record signal; a control means (3) for generating a first and second control signal, said first control signal driving said deck means (4) in a record mode so as to load an empty video tape and thereafter to pause said video tape recorder when a record key signal is inputted together with said synchronous record signal, said second signal driving said deck means in a playback mode so as to load a recorded video tape and thereafter to bring said video tape recorder into a still mode when a playback key signal is inputted together with said synchronous record signal; characterized by further comprising,a pilot signal generating means (6) for generating a first pilot signal of a given frequency in response to said first control and for providing said first pilot signal to an output of said video tape recorder; a pilot signal detection means (66) for detecting a second pilot signal from a mixed signal received via an input of the video tape recorder; and an integrating circuit (67) for integrating said second pilot signal; a comparator (68) for comparing the integrated signal of said integrating circuit with a reference signal so as to detect said pilot signal in order to change said video tape recorder from said pause into said record mode; a further pilot signal generating means (6) for generating a second pilot signal of a given frequency in response to receipt of a first pilot signal at an input of the video tape recorder; a signal mixer (64) for mixing the second pilot signal and an audio signal generated during a playback mode of the video tape recorder and providing the mixed signal to an output of the video tape recorder. Video tape recorder according to claim 1, wherein said pilot signals consist of an inaudible frequency transmitted to the audio line input/output terminal of said video tape recorder. Method for dubbing a recorded video tape simultaneously with the playing back of said video tape by using a first and second video tape recorder each having a mode selection key means for generating a plurality of key signals so as to perform various functions including record and playback functions, and a deck means for playing back and recording a video tape in response to said key signal, said method comprising the steps of: loading a recorded video tape in said first video tape recorder and afterwards bringing the first video tape recorder in a still mode when said first video tape recorder receives a playback key input signal together with a synchronous record signal; loading an empty video tape in said second video tape recorder and afterwards bring the second video tape recorder in a pause mode when said second video tape recorder receives a record key input signal together with a synchronous record signal; characterized by further comprising the steps of,generating in said second video tape recorder a first pilot signal of a given frequency for indication that said second video tape recorder is prepared to perform the recording function and providing said first pilot signal to said first video tape recorder; changing in said first video tape recorder in response to receipt of said first pilot signal said still mode in to playback mode ; generating in said first video tape recorder a second pilot signal and mixing it with the audio signal produced during the playback mode and providing the mixed signal to said first video tape recorder; and changing in said second video tape recorder in response to receipt of said second pilot signal the pause mode in to a record mode, thereby synchronizing the start of a playback function of the first video tape recorder with the start of the record function of said second video tape recorder. Method for dubbing a recorded video tape simultaneously with the playing back of said video tape as claimed in claim 3, wherein said pilot signals have an inaudible frequency. Method for dubbing a recorded video tape simultaneously with the playing back of said video tape as claimed in claim 3 or 4, wherein said pilot signals are transmitted through the audio line input/output terminals of said first and second video tape recorders. | SAMSUNG ELECTRONICS CO LTD; SAMSUNG ELECTRONICS CO., LTD. | HONG KWONG-PYO; HONG, KWONG-PYO |
EP-0490143-B1 | 490,143 | EP | B1 | EN | 19,960,131 | 1,992 | 20,100,220 | new | A61B17 | A61L17, B65H71 | A61L17, A61B17 | K61B17:06A9, A61B 17/06T, A61B 17/06A, A61B 17/06S, K61B17:00M | Method and apparatus for tipping sutures | A method and apparatus for tipping surgical sutures which includes winding the suture around a drum (26) while continuously monitoring the suture diameter in X and Y directions and adjusting the tension on the suture to control the suture diameter as it is being wound. The drum is then placed in an apparatus (100) which passes selected portions of the suture through a mist of caynoacrylate tipping agent generated by ultrasonic atomization (160). The tipping agent quickly cures and the tipped portion of the suture may be cut to create a tipped end for insertion into a surgical needle to form a needle suture device. | BACKGROUND OF THE INVENTION1. Field of the InventionThis invention relates to a method and apparatus for making a cyanoacrylate tipped surgical suture and a combined tipped suture and surgical needle. In particular, it relates to the use of a cyanoacrylate tipping agent for braided sutures to prevent brooming and to increase stiffness, thereby facilitating attachment of the suture to a surgical needle. 2. Background of the ArtFor many years, surgeons have employed needle-suture combinations in which a suture or ligature is attached to the shank end of a needle. Such needle-suture combinations are provided for a wide variety of monofilament and braided suture materials, both absorbable and non-absorbable, e.g., catgut, silk, nylon, polyester, polypropylene, linen, cotton, and absorbable synthetic materials such as polymers and copolymers of glycolic and lactic acid. Needle-suture combinations fall into two general classes: standard, or non-detachable, needle attachment and removable, or detachable, needle attachment. In the case of standard needle attachment, the suture is securely attached to the needle and is not intended to be separable therefrom, except by cutting or severing the suture. Removable needle attachment, by contrast, is such that the needle is separable from the suture in response to a force exerted by the surgeon. Minimum acceptable forces required to separate a needle from a suture (for various suture sizes) are set forth in the UnitedStatesPharmacopoeia (USP). As to detachable needles, the UnitedStatesPharmacopoeia prescribes minimum individual pull-out forces and minimum average pull-out forces as measured for five needle-suture combinations. The minimum pull-out forces for both standard and removable needle-suture attachment set forth in the UnitedStatesPharmacopoeia are hereby incorporated by reference. One typical method for securing a suture to a needle involves providing a cylindrical recess in the shank end of a needle and securing a suture therein. For example, U.S. Patent No. 1,558,037 teaches the addition of a cement material to such a substantially cylindrical recess to secure the suture therein. Additional methods for bonding a suture within a needle bore are described in U.S. Patent Nos. 2,928,395 (adhesives) and 3,394,704 (bonding agents). Alternatively, a suture may be secured within an axial bore in a needle by swaging the needle in the region of the recess. See, e.g., U.S. Patent No. 1,250,114. Additional prior art methods for securing a suture within a needle bore include expansion of a catgut suture through the application of heat (U.S. Patent No. 1,665,216), inclusion of protruding teeth within the axial bore to grasp an inserted suture (U.S. Patent No. 1,678,361) and knotting the end of the suture to be inserted within the bore to secure the suture therein (U.S. Patent No. 1,757,129). Methods for detachably securing a suture to a needle are also well known. For example, U.S. Patent Nos. 3,890,975 and 3,980,177 teach swaging a suture within a needle bore such that the suture has a pull-out value of 0.834 to 7.228 N (3 to 26 ounces). Alternative detachable attachment methods include providing a weakened suture segment (U.S. Patent No. 3,949,756), lubricant tipping the end of a suture to be inserted in the axial bore of a needle (U.S. Patent No. 3,963,031) and pre-tensioning a suture that is swaged within an axial needle bore (U.S. Patent No. 3,875,946). See also, U.S. Patent Nos. 3,799,169; 3,880,167; 3,924,630; 3,926,194; 3,943,933; 3,981,307; 4,124,027; and, 4,127,133. Another method for attaching a suture to a needle involves the use of tubing which is secured to the shank end of the needle and to the suture. For example, U.S. Patent No. 1,613,206 describes the use of a tubing (preferably silver) which is secured to the shank end of a needle and to a ligature. It is suggested that the tube may be attached to the needle by pressure or soldering and to the ligature by pressure or cementing. It is also suggested that the shank of the needle be of reduced cross section and that the furthest extremity of the reduced diameter shank section be provided with a spike or point upon which the suture may be secured prior to tube application. U.S. Patent No. 2,240,330 describes a tubing attachment method whereby the tubing and suture are releasably secured to the needle. In particular, the needle and tubing are provided with cooperating catch and abutment means which are released one form the other by rotating the needle 90° relative to the tubing (or vice versa). The tubing is manufactured from spring-tempered carbon steel or chrome nickel steel and is secured to the suture by heating the tubing and then swaging to the suture. U.S. Patent No. 3,311,100 related to a flexible composite suture having a tandem linkage. The needle is secured to a flexible suture leader manufactured from a readily sterilizable plastic such as nylon, linear polyethylene, isostatic polypropylene, polyester, silk or other proteinaceous material, e.g., by inserting and crimping the leader within an axial bore in the needle shank. The opposite end of the suture leader is crimped within a connector sleeve of a thin walled metal tubing, e.g., stainless steel. The opposite end of the tubing is crimped around a steel suture, e.g., monofilament stainless steel. U.S. Patent No. 3,918,455 describes a needle-suture attachment wherein a hollow suture portion is secured to the shank end of a needle which is of reduced cross-section as compared to the remainder of the needle. Additional patents which describe the use of tubing to effect suture-needle attachment include U.S. Patent Nos. 4,672,734 (forming needle from U-shaped metal plate around suture), 4,359,053 (silicone tubing), 3,835,912 (laser welding of metal tube to needle), 2,814,296, 2,802,468 (chamfered tubing ends), 2,302,986, 2,240,330, 1,981,651 (needle and tubing screw threaded), 1,960,117, and 1,591,021. In addition to the needle-suture constructions of the aforedescribed pull-out variety, it is known from U.S. Patent No. 4,805,292 to provide a needle-suture combination in which a suture cutting edge is formed at the shank end of the needle. However, the combined needle-suture device of U.S. Patent No. 4,805,292, like others described above, possesses a suture tip-receiving axial bore, or recess, formed in the butt end of the needle and as such is subject to the disadvantages recounted above which are associated with a needle possessing an axial bore. Insertion of sutures into a hole, recess or tube for attachment to surgical needles presents problems peculiar to suture needle combinations. Braided multifilament sutures in particular are difficult to insert into the very small aperture of a surgical needle: unless modified, they are too limp for the suture tip to be controlled for insertion and they have a tendency to broom , i.e., the filaments have a tendency to flare out at the cut end so that the diameter of the cut end exceeds the diameter of the needle hole. Various techniques have been employed to modify sutures to overcome the problems of limpness and brooming. One known method employs a tipping agent, which is a material used to coat the suture to stiffen the filaments and adhere them together. Typically, a suture to be tipped is first placed under tension to reduce slack so that the suture may be maintained in a predetermined position on a frame or rack or other suture holding device. Optionally, the tension may be such as to reduce the diameter of the suture. See Canadian Patent No. 1,009,532. The suture is then dipped into the tipping solution and allowed to dry while under tension. The sutures are then dried, such as by being warmed in a drying oven at about 107.21°C (225°F) for about 10 minutes. After drying the sutures can be cut and released from tension. The process results in a tipped end on each side of a cut. Where tension has optionally been employed to reduce the suture diameter, release of said tension will allow the suture to expand to its original diameter except at the tipped end portion. This can facilitate insertion of the end into a needle. Tipping agents may be dissolved in solvents to form dipping solutions. By way of example, Mariotte mixture is a dipping solution comprising nylon dissolved in isopropyl alcohol. Other polymers and solvents may also be used. Gould mixture is a dipping solution comprising nylon dissolved in methanol. At least one major manufacturer of surgical needles recommends use of Mariotte mixture or Gould mixture for tipping sutures. A multitude of other tipping agents, including polymers and solvents, have been proposed. For example McGregor U.S. Patent No. 3,890,975 discloses coating the suture with a binding resin or adhesive. The composition may be any non-toxic adhesive composition, either organic, inorganic or a hybrid. Suitable organic materials are such natural products as starch, dextrin, asphalt, animal and vegetable proteins, natural rubber, shellac, semi-synthetic products such as cellulose nitrate and the other cellulosics, polyamides derived from dimer acids, castor-oil based polyurethanes; such well-known synthetic resins as vinyl-type addition polymers, both resins and elastomers; polyvinyl acetate, polyvinyl alcohol, acrylics, unsaturated polyesters, butadiene/acrylonitrile, butadiene/styrene, neoprene, butyl rubber, polyisobutylene; and polymers formed by condensation and other step-wise mechanisms, i.e., epoxies, polyurethanes, polysulfide rubbers, and the reaction products of formaldehyde with phenol, resorcinol, urea, and melamine. McGregor states that particularly preferred bonding compositions are epoxide resins and polyester resins. Schmitt U.S. Patent No. 3,736,646 discloses that it is known to tip braided sutures by dipping the end of the suture in a plastic such as a solution in isopropyl alcohol. Schmitt suggests that for absorbable sutures an absorbable tipping agent is desirable, and proposes that a copolymer of lactic and glycolic acid dissolved in a suitable organic solvent, such as xylene or toluene, be applied to tip the suture. Nichols U.S. Patent No. 2,734,506 discloses a dipping solution of polymers of methacrylic acid esters in an organic solvent such as toluene, xylene acetone, ethyl acetate, methylethyl ketone, or naphtha. Shepherd et al. U.S. Patent No. 3,849,185 discloses the use of an acrylic casting syrup as a tipping agent, the syrup being fully polymerized after being applied to the suture. In addition, paraffin/hexane solution (10% paraffin) has been used as a suture coating agent as well as Arrochem (TM), a nylon resin plus methanol composition manufactured by ArroChem, Inc. of 201 Westland Farm Road, Mt. Holly, NC 28120, and SILASTIC (TM) Medical Adhesive (a silicon elastomer composition manufactured by Dow Corning Co. Although dipped sutures prepared in accordance with the above procedures may have been used successfully, there are several drawbacks with the use of tipping solutions. The main problems relate to tipping consistency and process control. Non-uniform solvent evaporation, which may be caused by variations in the solvent, oven temperature and heating time can result in inconsistent tipping. Furthermore, the dried residue of polymer left after evaporation can flake off or develop cracks. Another method which has been employed for treating sutures involves melt fusion, as described in U.S. Patent No. 4,832,025, issued to Coates. The suture is heated to a temperature at least high enough to melt fuse a portion of the outer filaments of the suture. According to Coates, such temperature is typically about 260°C to 300°C (500°F to 572°F). Exposure of synthetic sutures to such extreme temperatures melt fuses the filaments, and the melt fused suture portion stiffens upon cooling. Melting of the filaments has the effect of holding the filaments together when the suture is cut. It also causes stiffening of the suture which facilitates insertion of the suture end into the drilled hole of a needle. However, the melt fusion of suture has significant drawbacks. Firstly, the melt fusion of filaments weakens the suture, whose tensile strength is degraded in proportion to the extent of melt fusion. Secondly, melt fusion causes an irreversible change in the filaments which result in permanent stiffening and permanent loss of tensile strength. Thirdly, with the extreme temperatures disclosed by Coates for melt fusion an inconveniently short heating cycle is required. For example, for a size 3/0 silicone coated polyester suture heated to between 260°C to 300°C in a 4 mm. diameter heating tunnel, the heating time is no more than about 3 seconds. Such short heating times make it difficult to control the process and leads to inconsistencies and variations in the melt fused tipping process. A further consideration pertinent to suture tipping is that sutures are often prepared with lubricant coatings such as silicone or fatty acid salts in order to increase lubricity and to improve tie-down performance, i.e., the ease of sliding a knot down the suture into place. Such lubricant coatings typically are incompatible with the materials and methods currently employed for tipping sutures. In particular, prior known tipping agents do not adhere well to lubricant coated sutures, which may result in inconsistent tipping or an undesirable reduction of suture-needle pull out force. The melt fusing method of tipping may destroy the lubricant coating or render it less effective in areas away from the needle. A method of and apparatus for tipping surgical sutures has been discovered which may be used to tip both uncoated and coated sutures and which provides superior stiffening of the suture for insertion into an opening to attach the suture to a needle. SUMMARY OF THE INVENTIONA surgical suture tipped with cyanoacrylate and a process for tipping with cyanoacrylate are disclosed. In addition, a method and apparatus are provided herein for handling and tipping a surgical suture. In the preferred embodiment a suture is wound around a drum while its diameter is continuously monitored in the x and y directions, with the tension on the suture continuously being adjusted to consistently control the diameter of the suture as it is wound onto the drum. The drum is then placed in an apparatus which passes selected portions of the suture through a mist of cyanoacrylate tipping agent generated by sonic or ultrasonic atomization. The tipping agent quickly cures as it polymerizes in response to ambient residual moisture to stiffen the coated portion of the suture. The coated portion of the suture may be cut to create at least one tipped end for insertion into a surgical needle. To assure consistent repeated processing the atomization apparatus is flushed before and after each cycle with nitrogen in order to prevent curing of the cyanoacrylate in the apparatus, which would undesirably interfere with proper operation of apparatus. Advantageously, cyanoacrylate tipping in accordance with the invention can be used effectively to tip all types of sutures, including filled sutures and sutures coated with lubricants and the like. BRIEF DESCRIPTION OF THE DRAWINGSFig. 1 is a partially cutaway side view illustrating a surgical needle and suture combination. Fig. 2 is an exploded perspective view illustrating a surgical needle in conjunction with a suture. Fig. 3 is a partially cutaway side view illustrating a surgical needle in combination with a suture. Fig. 4 is a diagrammator illustration of the suture winding system of the present invention. Fig. 5 is a side elevational view of the suture winding apparatus of the present invention. Fig. 6 is a perspective view of the suture winding drum of the present invention. Fig. 6A is an end view of a rib configuration associated with the suture winding drum. Figs. 6B and 6C show end elevational views of drums having 2 and 3 notches, respectively. Fig. 7 is a side view of the suture retaining clamp of the present invention. Fig. 8 is a perspective view of the main support of the suture clamp. Fig. 9 is a perspective view of the dowel arm support of the present invention. Fig. 10 is a perspective view of the dowel arm of the present invention. Fig. 11 is a perspective view of the rocker clamp support of the present invention. Fig. 12 is a perspective view of the rocker clamp of the present invention. Fig. 13 is a perspective view of the rocker spring of the present invention. Fig. 14 is a perspective view of the suture tipping apparatus of the present invention. Fig. 15 is a cut away front elevational view of the suture tipping apparatus of the present invention. Fig. 16 is a cut away side elevational view of the suture tipping apparatus of the present invention. Fig. 17 is a front sectional view of the spray head assembly of the suture tipping apparatus. Fig. 18 is a partially cut away side view of the spray head assembly of the suture tipping apparatus. Fig. 19 is a perspective view of a suture with a tipped portion. Fig. 20 is a schematic illustration of the suture tipping system of the present invention. Fig. 21 illustrates the placement of clamps on the drum to secure the suture for a cutting procedure. DETAILED DESCRIPTION OF PREFERRED EMBODIMENTSThe present invention is generally directed to tipping surgical sutures with cyanoacrylate in order to stiffen the suture tip and, as to multifilament sutures, prevent brooming. Tipping the suture with cyanoacrylate facilitates insertion of the suture tip into an opening for attachment to a suture. Advantageously, the cyanoacrylate tipping is compatible with a broad range of sutures and coatings, and a novel method and apparatus have been developed for applying cyanoacrylate to sutures in an atomized spray. Because the cyanoacrylate tipping agent and process are applicable to a wide range of materials and needle suture attachment methods, suture constructions and general methods of tipping sutures will be discussed prior to discussing the preferred apparatus for spray tipping. The SutureThe present invention is primarily directed to the treatment of braided surgical sutures. The term braid means a substantially symmetrical strand formed by crossing a number (at least three) of individual strands composed of one or more filaments diagonally in such manner that each strand passes alternatively over and under one or more of the others. The braid may be of traditional tubular braid construction or spiroid braid construction and may include a core section composed of one or more filaments around which the braid is externally fabricated. The braided suture can be fabricated from a wide variety of natural and synthetic fibrous materials such as any of those heretofore disclosed for the construction of sutures. Such materials include non-absorbable as well as partially and fully bio-absorbable (i.e., resorbable) natural and synthetic fiber-forming polymers. Non-absorbable materials which are suitable for fabricating braided sutures include silk, polyamides, polyesters such as polyethylene terephthalate, polyacrylonitrile, polyethylene, polypropylene, silk cotton, linen, etc. Carbon fibers, steel fibers and other biologically acceptable inorganic fibrous materials can also be employed. Bio-absorbable sutures may be fabricated from natural collagenous material or synthetic resins including those derived from glycolic acid, glycolide, lactic acid, lactide, dioxanone, polycaprolactone, epsilon-caprolactone, trimethylene carbonate, etc., and various combinations of these and related monomers. Sutures prepared from resins of this type are known in the art. Braided multifilament sutures typically are coated with one or more coating compositions to improve functional properties such as surface lubricity and knot tie-down behavior. A variety of suture coating compositions proposed for either or both of these purposes are well known in the art, e.g., those disclosed in U.S. Patent Nos. 3,867,190; 3,942,532; 4,047,533; 4,452,973; 4,624,256; 4,649,920; 4,716,203; and 4,826,945. A preferred lubricant coating is a bioabsorbable coating composition obtained by copolymerizing in accordance with known procedures (1) a polyether glycol selected from the group consisting of relatively low molecular weight polyalkylene glycol, e.g., one corresponding to the general formula HO(RO)yH wherein R is an alkylene group of from 2-4 carbon atoms and y is an integer of from about 100-350, and polyethylene oxide-polypropylene oxide block copolymer, e.g., one corresponding to the general formula H(OCH₂CH₂)x(OC₃H₆)y(OCH₂CH₂)zOH wherein x is an integer of from about 45-90, y is an integer of from about 60-85 and z is an integer of from about 45-90 with (2) a mixture of lactide monomer and glycolide monomer or a preformed copolymer of lactide an glycolide, the weight ratio of (1) to (2) preferably ranging from about 4:1 to about 1:4 and more preferably from about 2:1 to about 1:2. The ratio of lactide to glycolide in the monomer mixture or in the copolymer of these monomers preferably varies from about 65-90 mole percent lactide and 10-35 mole percent glycolide. Polyether glycols having molecular weights of about 3,500-25,000 and preferably from about 4,000-10,000 and polyethylene oxide-polypropylene oxide block copolymers having molecular weights of from about 4,000-10,000 and preferably from about 7,500 to about 9,000, e.g., those disclosed in U.S. Patent Nos. 2,674,619, 3,036,118, 4,043,344 and 4,047,533 and commercially available as they Pluronics (BASF-Wyandotte). Where preformed copolymers of lactide and glycolide are employed in preparing the bioabsorbable coating compositions, they may be prepared as described in U.S. Patent No. 4,523,591. The amounts of bioabsorbable coating composition to be applied to the suture, e.g., by coating, dipping, spraying or other appropriate techniques, will vary depending upon the specific construction of the suture, its size and the material of its construction. In general, the coating composition applied to an unfilled suture will constitute from about 1.0 to about 3.0 percent by weight of the coated suture, but the amount of coating add on may range from as little as about 0.5 percent, by weight, to as much as 4.0 percent or higher. For a preferred filled (i.e. containing a storage stabilizing agent) braided suture, amounts of coating composition will generally vary from about 0.5% to about 2.0% with as little as 0.2% to as much as 3.0%. As a practical matter and for reasons of economy and general performance, it is generally preferred to apply the minimum amount of coating composition consistent with good surface lubricity and/or knot tie-down characteristics and this level of coating add on is readily determined experimentally for any particular suture. Recently it has been proposed to also apply to an absorbable braided suture a storage stabilizing amount of a filler material containing at least one water soluble liquid polyhydroxy compound and/or ester thereof. In addition to having an enhanced degree of storage stability, a braided suture which has been filled with a storage stabilizing amount of, e.g., glycerol, exhibits better flexibility and hand characteristics than the untreated suture. Moreover, since the polyhydroxy compounds are generally capable of dissolving a variety of medico-surgically useful substances, they can be used as vehicles to deliver such substances to a wound or surgical site at the time the suture is introduced into the body. The useful storage stability agents are generally selected from the water soluble, liquid polyhydroxy compounds and/or esters of such compounds, preferably those having no appreciable toxicity for the body at the levels present. The expression liquid polyhydroxy compound contemplates those polyhydroxy compounds which in the essentially pure state are liquids, as opposed to solids, at or about ambient temperature, e.g., at from about 15°C to about 40°C. The preferred polyhydroxy compounds possess up to about 12 carbon atoms and where the esters are concerned, are preferably the monoesters and diesters. Among the specific storage stabilizing agents which can be used with generally good results are glycerol and its mono- and diesters derived from low molecular weight carboxylic acids, e.g., monoacetin and diacetin (respectively, glyceryl monoacetate and glyceryl diacetate), ethylene glycol, diethylene glycol, triethylene glycol, 1,3-propanediol, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, and the like. Glycerol is especially preferred. Mixtures of storage stabilizing agents, e.g., sorbitol dissolved in glycerol, glycerol combined with monoacetin and/or diacetin, etc., are also useful. To prevent or minimize run-off or separation of the storage stabilizing agent from the suture, a tendency to which relatively low viscosity compounds such as glycerol are especially prone, it can be advantageous to combine the agent with a thickener. Many kinds of pharmaceutically acceptable non-aqueous thickeners can be utilized including water-soluble polysaccharides, e.g., hydroxypropyl methycellulose (HPMC), and the other materials of this type which are disclosed in European Patent Application 0 267 015 referred to above, polysaccharide gums such as guar, xanthan, and the like, gelatin, collagen, etc. An especially preferred class of thickeners are the saturated aliphatic hydroxycarboxylic acids of up to about 6 carbon atoms and the alkali metal and alkaline earth metal salts and hydrates thereof. Specific examples of such compounds include salts of lactic acid such as calcium lactate and potassium lactate, sodium lactate, salts of glycolic acid such as calcium glycolate, potassium glycolate and sodium glycolate, sales of 3-hydroxy propanoic acid such as the calcium, potassium and sodium salts thereof, salts of 3-hydroxybutanoic acid such as calcium, potassium and sodium salts thereof, and the like. As stated hereinabove, hydrates of these compounds can also be used. Calcium lactate, especially calcium lactate pentahydrate, is a particularly preferred thickener. When a thickener is utilized, it will be incorporated in the filling composition in at least that amount required to increase the overall viscosity of the storage stabilizing agent to the point where the agent no longer readily drains away from the suture in a relatively short period. In the case of a preferred storage stabilizing agent-thickener combination, namely, glycerol and calcium lactate, the weight ratio of glycerol to calcium lactate can vary from about 1:1 to about 10:1 and preferably is from about 6:1 to 8:1. If necessary or desirable, the storage stabilizing agent together with optional thickener can be dissolved in any suitable non-aqueous solvent or combination of solvents prior to use. To be suitable, the solvent must (1) be miscible with the storage stabilizing agent and optional thickener, if present (2) have a sufficiently high vapor pressure to be readily removed by evaporation, (3) not appreciably affect the integrity of the suture and (4) be capable of wetting the surface of the suture. Applying these criteria to a preferred storage stabilizing agent, glycerol, advantageously in admixture with a preferred thickener, calcium lactate, lower alcohols such as methanol and ethanol are entirely suitable solvent carriers. When a solvent is utilized in the preparation of the stabilizing agent, e.g., methanol, such solvent can be employed in amounts providing a solution concentration of from about 20% to about 50%, preferably about 30% to about 45%, by weight of the storage stabilizing agent including any optional thickener. As stated, a braided suture may be impregnated with one or more medico-surgically useful substances, e.g., those which accelerate or beneficially modify the healing process when the suture is applied to a wound or surgical site. So, for example, the braided suture herein can be provided with a therapeutic agent which will be deposited at the sutured site. The therapeutic agent can be chosen for its antimicrobial properties, capability for promoting wound repair and/or tissue growth or for specific indications such as thrombosis. Antimicrobial agents such as broad spectrum antibiotics (gentamicin sulphate, erythromycin or derivatized glycopeptides) which are slowly released into the tissue can be applied in this manner to aid in combating clinical and sub-clinical infections in a surgical or trauma wound site. To promote wound repair and/or tissue growth, one or more biologically active materials known to achieve either or both of these objectives can be applied to the braided suture of the present invention. Such materials include any of several Human Growth Factors (HGFs), magainin, tissue or kidney plasminogen activator to cause thrombosis, superoxide dismutase ot scavenge tissue damaging free radicals, tumor necrosis factor for cancer therapy, colony stimulating factor, interferon, interleukin-2 or other lymphokine to enhance the immune system, and so forth. The filling composition can contain one or more additional components which promote or enhance the wound healing effectiveness of the HGF component. Thus, e.g., site-specific hybrid proteins can be incorporated in the filling composition to maximize the availability of the HGF at the wound site and/or to potentiate wound healing. See e.g., Tomlinson (Ciba-Geigy Pharmaceuticals, West Sussex, U.LK.), Selective Delivery and Targeting of Therapeutic Proteins , a paper presented at a symposium held June 12-14, 1989 in Boston, MA, the contents of which are incorporated by reference herein. The HGFs can also be associated with carrier proteins (CPs), e.g., in the form of CP-bound HGF(s), to further enhance availability of the HGF(s) at a wound site as disclosed in Carrier Protein-Based Delivery of Protein Pharmaceuticals , a paper of BioGrowth, Inc., Richmond, CA presented at the aforementioned symposium, the contents of said paper being incorporated by reference herein. The HGFs can also be incorporated in liposomes to provide for their release over an extended period. Lactate ion can be present to augment the wound healing activity of the HGF. Protectants for the HGF can also be utilized, e.g., polyethylene glycols, acetoxyphenoxy polyethoxy ethanols, polyoxyethylene sorbitans, dextrans, albumin, poly-D-alanyl peptides and N-(2-hydroxypropyl)methacrylamide (HPMA). Cyanoacrylate TippingAs stated previously, prior known tipping methodologies are not fully compatible with a suture or its coatings, fillers, therapeutic agents, antimicrobial agents and/or biologically active materials, either because the tipping agent will not adhere properly or because the methodology (such as melt fusing) results in deterioration of the suture, its coatings, additives, and fillers. The suture tipping agent and method of the present invention are compatible with and may be used on any type of surgical suture including multifilament bioabsorbable or non-bioabsorbable sutures. Advantageously, the tipping agent and method of the invention are applicable to all types of multifilament braided sutures, including those which contain one or more fillers, coatings, etc. In practice, a segment of the suture is selected for tipping and may be of any length appropriate for inserting a suture end cut from such segment into an opening, such as the barrel end of a surgical needle, to facilitate attachment of the suture to the needle. Typically the suture is placed under sufficient tension to take up slack. Additional tension may be applied to reduce the suture diameter, if desired, to result in a tipped section of reduced diameter relative to the remainder of the suture. A stiffening or tipping agent is then applied to the selected segment of suture. The stiffening agent is a cyanoacrylate monomer such as methyl 2-cyanoacrylate, or ethyl 2-cyanoacrylate. The preferred cyanoacrylate is available under the name LOCTITE(TM) Medical Device Adhesive 18014 and is available from the Loctite Corporation, 705 N. Mountain Road, Newington, CT 06111. The preferred Loctite Medical Device Adhesive is a moisture activated polymer which comprises 99+% ethyl cyanoacrylate and small amounts of hydroquinone and organic anhydride. It has a specific gravity of 1.05, and a boiling point greater than 300°F (148°C). The cyanoacrylate monomer may be applied in a variety of ways, such as dipping or brushing and preferably is applied by spraying, as described below. Upon contact with the suture, the residual moisture of the suture and surrounding environment catalyzes the polymerization of the cyanoacrylate almost instantly. The polymerized cyanoacrylate stiffens the segment of the suture by coating the individual filaments of the suture with a relatively stiff coating, and, because the cyanoacrylate is an adhesive, the individual filaments are bonded together to prevent brooming. A further advantage of the ethyl cyanoacrylate tipping agent is that it is bioabsorbable and will not leave a permanent residue in body tissue. Because the cyanoacrylate polymerizes almost instantly, the tipping agent is stiffened immediately without any additional drying or curing steps. This has the added advantage of reducing processing steps and accompanying handling and equipment requirements. In the preferred spray tipping process, polymerization is substantially complete by the end of the apparatus cycle and the tipped suture may be further processed without delay. The next step is cutting the stiffened segment to create at least one tipped end for connecting to the end of a surgical needle. Two tipped ends of the suture may be desirable for attaching a needle to each end of the suture to provide a so-called double armed suture. The coated segment may be cut with scissors, a razor blade, or by a knife edge moving transverse to the direction of the tipped suture segment, or by any other suitable means. Suture-Needle AttachmentThe tipped end is now ready to be connected to the surgical needle. One method of connection, illustrated in Fig. 1, requires a needle 1 with a barrel end having an axial aperture 1a. The tipped end of suture 2 is inserted into the aperture 1a and the end of the needle may then be swaged, crimped or otherwise constricted to grip and hold the suture, either permanently or with a pull-out force defined by U.S.P. for detachable needles. The swage or crimp method of attachment is conventional and well known in the art. Another method of attaching the suture to the needle is illustrated in Fig. 2 wherein the barrel end of the needle 1 has a cylindrical portion 1b of lesser diameter than the needle and extending axially from the needle 1. The tipped or stiffened end 2a of suture 2 is positioned adjacent portion 1b and extends axially through the bore of a tube 3, which is positioned around the junction of tipped end 2a and needle portion 1b. Tube 3 is made of a material capable of shrinking or undergoing contraction upon application of energy, e.g., heat. Suitable materials include memory based metals, e.g., nickel-iron-titanium mixtures, or copper based materials, as are well known in the art (see, e.g., U.S. Patent Nos. 3,759,552, 3,801,954, 4,198,081 and 4,733,680), and shrinkable plastic materials, such as polyvinylidene fluoride materials available from Raychem Corporation, Menlo Park, California, under the tradename Kynar. One such polyvinylidene fluoride material available from Raychem Corporation is RT-850. In the case of shrinkable plastic materials, the tubing typically is extruded such that the inner diameter is less than the final desired diameter, i.e., the inner diameter of the tubing after energy application in the attachment method of the present invention. Thereafter, the extruded tubing is expanded radially outward through radial expansion means to provide a tubing or expanded inner diameter. Such plastic tubing is thus adapted to shrink or recover to its original extruded inner diameter in response to the application of a predetermined amount of energy. Suitable energy sources to accomplish shrinking of tubing 3 include heat (convective or conductive), radiation, microwave energy, etc. Tube 3 is then subjected to energy, preferably consisting of heat, in order to cause shrinkage or contraction of the tube such that the inner surface of the tube bore grips both the needle portion 1a and the suture end 2a in the vicinity of the joint as shown in Fig. 3. Alternatively, the tube may be attached to the needle and suture sequentially such as by first applying localized energy to shrink the tube onto the needle shank and thereafter applying energy to the remainder of the tube to shrink the tube into the suture tip. Variations in the needle shank, such as tapering, contouring or ribbing, may be used to increase gripping force of the tube to the needle. Similarly, the relative gripping force of the tube on the needle shank and suture may be varied by varying the length of the tube section contacting each of the needle shank and suture. In addition, tube 3 preferably is configured and dimensioned such that when it is contracted the outer surface of the tube is substantially flush or even with the outer surface of the needle. The gripping force of the shrinkable tube 3 is sufficient to maintain the minimum required pull out force for the suture, and may be adjusted to provide either permanently attached or detachable suture needles. It has been found that sutures, particularly coated and filled sutures, tipped in accordance with the method of the present invention have significantly higher pull out forces. Attempts were made to tip coated sutures, such as silicone coated Dacron® braided sutures, with polyurethane and epoxy adhesives. These attempts did not result in any tipped sutures suitable for attachment to needles. Comparative Examples 1-2Dacron® polyester 1-0 braided sutures coated with silicone were tipped by swab application of (i) Arrochem composition; and (ii) a hot melt 10% paraffin/hexane solution. Sutures tipped with the 10% paraffin/hexane were further treated for 60 seconds in a heating apparatus set at 315°F (154°C). The 10% paraffin/hexane solution was difficult to work with since it had to be maintained at about 54.4°C (130°F) with constant stirring in order to maintain the paraffin in solution. The tipped sutures were swaged to needles in a conventional manner and pull-out force in both cases was measured to be about 0.05 kg. Comparative Example 3In an attempt to improve on the results of Comparative Examples 1-2, Dacron® polyester 1-0 braided sutures were placed in toluene and brought to temperature of 80-82°C for ten minutes. The total dwell time in toluene was approximately 20 minutes. The washed sutures were tipped with 10% paraffin/hexane by swab application and heated to 315°F (154°C) for 60 seconds. The maximum pull-off forces were approximately 0.05 kg, showing no improvement. Comparative Examples 4-14Dacron® polyester 1-0 braided sutures coated with silicone were ultrasonically washed for five minutes in one of isopropyl alcohol, TP10, Freon TF, hexane, xylene, and III-trichloromethane. Samples of sutures washed by each method were tipped with Arrochem solution and 10% paraffin/hexane (the paraffin/hexane tipped sutures were heated to 315°F (154°C) for 60 seconds, as before), resulting in twelve types of differently treated and tipped sutures. The tipped sutures were swaged to needles and the pull-out force was measured. The pull-out forces of these sutures showed some improvement, having pull-out forces of about 1.5 kg, but still did not achieve reliably high pull-out forces. Comparative Examples 15-16Silicone coated Dacron® polyester 1-0 braided sutures were wound on a paddle and soaked for five minutes in a 5% Mariotte mixture solution (50 grams nylon in 946 ml. isopropyl alcohol and 150 ml. water). Thereafter, the sutures were heated for 60 seconds at 315°F (154°C) and, after cooling, Arrochem solution was applied over the tip previously treated with Mariotte mixture. No improvement in pull out force was obtained, and the extended exposure to Mariotte mixture was observed to have detrimental effects on the suture braid. The above procedure was repeated using a 10 minute soak in Mariotte mixture followed by heat treating for 10 minutes in an oven at 225°F (107°C), followed by tipping with Arrochem composition. No improvement in pull-out force was observed when these sutures were attached to needles. Comparative Example 17Silicone coated Dacron® polyester 1-0 braided sutures were ultrasonically washed for 5 minutes in toluene and tipped with 10% paraffin/hexane solution by swab application. The pull-off force met U.S.P. minimums, e.g. .45 kg, but was still insufficient. Comparative Examples 18-29Silicone coated Dacron® polyester 1-0 braided sutures were ultrasonically washed for 10 minutes in a variety of different washing solutions, tipped by soaking for 5 minutes in either Arrochem or 5% Mariotte mixture, and attached to needles. The results are listed below in Table I. Cleaning Solution Tipping Agent Pull-Off Force (kg) 18. Isopropyl alcoholArrochem0.05 - 1.0 19. Isopropyl alcoholParaffin/Hexane0.05 - 1.0 20. Freon T-FArrochem0.05 - 1.0 21. Freon T-FParaffin/Hexane0.05 - 1.0 22. Freon TP 10Arrochem0.05 - 1.0 23. Freon TP 10Paraffin/Hexane0.05 - 1.0 24. TrichloroethyleneArrochem0.05 - 1.0 25. TrichloroethyleneParaffin/Hexane0.05 - 1.0 26. XyleneArrochem0.08 - 1.3 27. XyleneParaffin/Hexane0.08 - 1.3 28. HexaneArrochem0.08 - 1.3 29. HexaneParaffin/Hexane0.08 - 1.3 Comparative Examples 30-33Braided Dacron® polyester size 1-0 braided sutures were ultrasonically washed in a toluene bath for 20 minutes. After solvent cleaning the sutures were tipped by soaking for 5 minutes in one of (i) 10% Silastic Medical Adhesive in hexane; (ii) 10% paraffin/hexane; (iii) Arrochem solution; or (iv) Mariotte mixture. All the tipped sutures were post-tipped at 315°F (154°C) for 60 seconds. The tipped ends were cut and inserted into surgical needles, the needles were swaged, and the pull out forces wore measured. The results are set forth in Table II. Pull-out forces for Dacron® polyester 1-0 braided sutures ultrasonically cleaned in toluene for 20 minutes. Tipping Agent Pull-out Force kg 30. Silastic/Hexane1.0 - 1.8 31. Paraffin/Hexane1.0 - 1.6 32. Arrochem1.3 - 1.8 33. Mariotte Mixture1.8 - 2.5 From the foregoing it would appear that ultrasonic washing in toluene for 20 minutes prior to tipping with a conventional agent might lead to acceptable results. Unfortunately, however, toluene is an undesirable material due to its toxicity and the harsh effects on the suture material. Examples 1-6Samples were selected for testing of (i) size O braided synthetic absorbable sutures made from 90% glycolide, 10% lactide coated with a glycolide/lactide/polyethylene oxide mixture, and filled with glycerin/calcium lactate; and (ii) braided nylon (non-bioabsorbable) sutures coated with silicone lubricant. Selected segments of the sutures were tipped with Loctite Selected segments of the sutures were tipped with Loctite Adhesive 18014, which was allowed to fully polymerize. The suture segments were cut to create tipped ends which were then inserted into a drilled hole in the barrel end of surgical needles. The needles were then swaged by a) double hit swaging, b) split-ring, and c) clover leaf dies, and pull out forces for each type of attachment were measured. Further information regarding split-ring and clover leaf swaging may be found in US-A-5 046 350 and US-A-5 099 676 (U.S. Patent Application Serial Nos. 07/431,303 and 07/431,306 both filed November 3, 1989). The test results are set forth in Tables III, IV and V below. Cyanoacrylate-Tipped Sutures Conventional Double-Hit Swaging SUTURE SIZE PRE-STERILIZATION PULL-OUT FORCE POST-STERILIZATION PULL-OUT FORCE SAMPLES AVG. RANGE SAMPLES AVG. RANGE 1. Synthetic Absorbable0n-5 2.6 kgs. - n-5 2.9 kgs.- 2. Braided Nylon0n-101.8 kgs.-n-101.8 kgs.- Cyanoacrylate-Tipped Sutures Split Ring Swaging SUTURE SIZE PRE-STERILIZATION PULL-OUT FORCE POST-STERILIZATION PULL-OUT FORCE SAMPLES AVG. RANGE SAMPLES AVG. RANGE 3. Synthetic Absorbable0n-153.2 kgs.2.9-3.7 kgs.n-83.1 kgs.2.5-3.4 kgs. 4. Braided Nylon0n-113.3 kgs.1.4-7.1 kgs.n-152.9 kgs.2.4-3.2 kgs. Cyanoacrylate-Tipped Sutures Clover Leaf Swaging SUTURE SIZE PRE-STERILIZATION PULL-OUT FORCE POST-STERILIZATION PULL-OUT FORCE SAMPLES AVG. RANGE SAMPLES AVG. RANGE 5. Synthetic Absorbable0n-153.5 kgs.2.8-4.4 kgs.n-153.3 kgs.2.5-4.1 kgs. 6. Braided Nylon0n-152.9 kgs.1.5-3.9 kgs.n-153.2 kgs.1.9-4.1 kgs. The minimum pull out force required by the U.S. Pharmacopeia for size 0 suture is 1.5 kg Avg/0.45 kg individual. As can be seen from Tables III, IV, and V, the pull out forces for the cyanoacrylate tipped sutures exceeds the minimum USP requirements. As can be seen from a comparison of the pull-out forces tabulated in the above examples and comparative examples, the suture tipping method of the present invention using cyanoacrylate tipping agent produces pull-out forces superior to those of methods using prior known tipping agents, particularly with respect to filled sutures and sutures coated with lubricant coatings. Remarkably, these results are attained without washing the suture prior to cyanoacrylate tipping. This is surprising since the prior known methods of using cyanoacrylates typically require the surface to be bonded to be free of oils, mold release agents, or other foreign matter in order to achieve maximum bond performance. Tipping ApparatusThe following description discloses the preferred apparatus for spraying cyanoacrylate monomer onto the suture by atomization. Method For Winding A SutureTo insure consistency of the diameter at the tipped portion of the suture, a method and apparatus have been developed for monitoring suture ovality and adjusting winding tension to control and, if desired, modify the suture diameter. A diagram of the system for loading sutures on a drum is illustrated in Fig. 4. The pay off section includes a spool 10 on which suture material 11 is stored. A friction tensioning device applies drag to the outside of the spool to prevent the spool from freewheeling. The suture is guided onto a capstan 12 which is electronically controlled by means of friction clutch 13 and clutch power supply 14. The suture 11 then passes onto the drum assembly 26. Power is supplied by standard 120 volt power sources 15. When tension is applied to the suture, the suture diameter is reduced. When the clutch is relaxed, the diameter of suture material under tension expands. Based on dimensional information continuously fed to the clutch control from an x-y laser micrometer 18, the clutch applies tension to or releases the suture in order to maintain suture diameter within selected parameters. The x-y laser micrometer 18 continuously monitors the diameter of the suture in the x and y directions, i.e. suture ovality, by means of x-y heads 19 which are oriented orthogonal to each other. The laser micrometer electronically compares the x-y measurements with preselected minimum and maximum dimensions pertaining to the particular type and size of suture. This information is employed in a negative feedback control loop whereby the clutch tension is adjusted by means of a drive motor 17 and potentiometer clutch controller 16. In the event either dimension exceeds the maximum diameter for the suture size, the clutch tension is increased in order to decrease the diameter of the suture. In the event either dimension is less than the minimum suture diameter the clutch tension is relaxed until the suture diameter is increased into the suture diameter range. The information is processed and clutch tension adjusted within milliseconds of the actual measurement to continuously adjust clutch tension. Referring more specifically to the laser micrometer, an instrument suitable for use in the present invention is available from Zumbach Electronics Corp., 140 Kisco Avenue, Mount Kisco, N.Y. 10549 under the designation ODAC 19M, which is a microcomputer controlled measuring system having x-y heads which incorporate laser scanners. Fig. 5 illustrates a side view of the suture handling apparatus. Suture storage spool 10 is rotatably mounted at the top of mounting frame 20. Suture 11 is drawn off and passes through guide 21, around capstan 12 and over and around guide roller 22. Suture 11 then passes through a second guide member 23, through laser micrometer 18 where the x-y measurements are made, around guide rollers 24 and 25, and finally onto drum 26. Drum 26 is mounted onto drum mounting frame 27 and is driven to receive suture 11 and maintain tension thereon. During winding of the suture onto drum 26, drum mounting frame 27 traverses in the plane perpendicular to Figure 5 so that the suture is continuously wound around the drum in a helix from one end of the drum to the other with no two adjacent suture portions touching. Figs. 6 and 7 illustrate the drum assembly 26 in greater detail. Referring to Fig. 6, the drum assembly comprises a substantially cylindrical drum 26 having a smooth circumferential surface 31. In order to facilitate gentle treatment of the sutures, the drum may be made of polished stainless steel or stainless steel covered with a silicon rubber skin. Most preferably, drum 26 is fabricated from high density polyethylene with steel end plates. High density polyethylene has been found to be particularly advantageous since excess cyanoacrylate does not adhere to this material during the tipping operation. Where the drum is constructed of high density polyethylene it further has been found desirable to reinforce the drum against deformation by providing a plurality of gussets or ribs inside the drum. An end view of one appropriate rib configuration is shown in Fig. 6A. Each rib has a thickness of about 0.635 to 1.905 cm (about ¼ to ¾ inches) in the direction perpendicular to the plane of Fig. 6A. The number of ribs may vary, but two to five ribs should be appropriate, and three ribs are preferred. Drum 26 could also be fabricated from a solid block of high density polyethylene, but the added weight of such a construction most likely will not be desired. Referring again to Fig. 6, a notch 32 extends lengthwise along the drum. When suture 11 is wound around the drum a portion of each suture wrap will extend across the notch orthogonally to the lengthwise orientation of the notch. The end plate 33h has central apertures 34 and an axial spindle 29 by which the drum can be mounted to fixture 27 such that the drum can be rotated to wind suture 11 thereon. Apertures 35 and 36 are for mounting the suture retainer clamps to hold the tipped sutures in place while the tipped section is cut to remove the sutures from the drum, as described below. Peripheral apertures 37 are for attachment of the end plates to the drum, such as by screw mounting, and aperture 38 is provided to receive a positioning pin on the tipping apparatus to hold the drum in the correct orientation during tipping. Of course, drums of different circumference can be made in order to provide tipped sutures of different lengths. By way of example only, drums having a circumference of 91.44, 76.2, 60.96 and 45.72 cm (thirty six, thirty, twenty four and eighteen inches) are contemplated. The cylindrical construction of the drum has the added advantage of being conducive to providing multiple longitudinal notches on drums of different circumference in order to be able to tip a variety of different length sutures in a single tipping operation. Figs. 6B and 6C show end elevational views of drums 26B and 26C having 2 and 3 notches, 32, respectively. It is contemplated that drums having the following general dimensions (inches) could be provided. Drum Circumference Number of Notches Tipped Suture Lengths 1535 1628 24212 Spray Tipping ApparatusThe present invention contemplates tipping a suture by passing the portion of the suture to be tipped through a mist or cloud of rapidly curing material, such as the cyanoacrylate monomer described above. The cyanoacrylate monomer is absorbed into the suture braid matrix and usually cures almost immediately. Misting of the cyanoacrylate monomer is achieved by passing it through an atomization nozzle which atomizes the liquid monomer by means of sonic/ultrasonic vibration. The tipping process is described more fully as follows. After the suture 11 has been wound on drum 26, the drum may be transferred to an apparatus 100 for tipping the suture. Such an apparatus is illustrated in Figs. 14, 15, and 16, which are now referred to. Drum assembly 26 with suture 11 wound thereon is mounted onto drum mounting carriage 110 in the loading chamber 101 of the suture tipping apparatus 100. Drum mounting carriage 110 has twin uprights 111 , each upright having a drum support plate 112 with notches 112a for receiving spindles 29 of the drum. Mounting carriage 110 also has a base 113 with a lower member 114 for slidably engaging rail 120 which extends longitudinally from the loading chamber 101 to the processing chamber 102. The loading chamber 101 may be accessed by means of cover panel 103 which can be pivoted upward to open the loading chamber 101. The tipping apparatus further includes a control panel 130, window 104, sonic control unit 140, liquid storage and transmission system 150, metering control system 170, exhaust port 190 (Fig. 16) for removing vapors of tipping agent and solvents, and a spray head assembly 160. The liquid storage system 150 includes solvent reservoir 213 and tipping solution reservoir 212 and associated transmission lines as discussed below with reference to Fig. 20. A plenum member 105 connected to a source of vacuum extends longitudinally within processing chamber 102 to a point below the spray head assembly 160. Plenum 105 is supported by plenum mount 106, which is braced by gusset 106a. Long and short manifolds 107 and 108, respectively, are below base 109. At the top of the unit 100 the sonic control unit 140 is a sonic/ultrasonic frequency signal generator. The signal is sent to the atomizer nozzle 161 of spray head assembly 160 described below. Atomizer nozzle 161 is the outlet for the tipping solution which creates a fine mist for spraying the suture. The electric signal from sonic control unit is transmitted by conductive wire to piezoelectric elements in the atomizer nozzle. A fluid passing through the nozzle is thereby atomized into a fine mist. A device suitable for use as the sonic control unit 140 in the present invention is manufactured by Sono-Tek Corporation of 313 Main Mall, Poughkeepsie, New York. The advantage to using sonic/ultrasonic atomization as opposed to pressurized spray is that lower flow velocities may be used. This eliminates bounceback of the sprayed material from the workpiece, which is a problem with pressure spraying. Another advantage of sonic/ultrasonic atomization over pressure atomization is that the outlet orifice diameter of the sonic/ultrasonic atomizer nozzle can be relatively wide while still providing a suitable mist of tipping agent. This helps prevent clogging of the orifice. Yet another advantage is that the atomization creates a cloud or mist which, when the suture is passed through, coats and saturates all sides of the suture, not just the side of the suture facing the outlet orifice of the atomizer. Thus, the application of tipping agent is not limited by line of sight impingement of tipping agent onto the suture, as would be the case with simple spray application. Referring now to Figs. 17 and 18, the spray head assembly 160 includes spray nozzle 161, which comprises a downwardly projecting member 161a having an internal bore 161h terminating in orifice outlet 161g. The cyanoacrylate tipping agent passes through said bore and is atomized to a fine mist 164 upon exiting the nozzle. Atomization is achieved by means of piezoelectric elements 161b and 161c which are electrically connected via wires 161d and 161e respectively to the Sono-Tek signal generating unit 140. The signals from the unit 140 may be varied in frequency to adjust the fineness of the mist. O-rings 161f provide a seal for the atomization nozzle 161. Blocks 162 have an internal chamber for an inert gas such as nitrogen, which is fed in through gas line 163. The gas exits via apertures 162b in the bottom of the blocks 162. Plenum member 105 has an aperture 105a positioned below the atomizer nozzle 161 so as to catch any excess spray. The aperture also permits the suture to be surrounded by the mist so that the entire suture, including the underside of the suture, is uniformly coated with the cyanoacrylate monomer. Fig. 20 is a schematic flow chart of the tipping system. Gas supply 219 is a source of inert gas, preferably nitrogen. Optionally, a source of compressed air may be provided with air being fed to the ports between tipping cycles, i.e. when the instrument is not being used. Nitrogen is sent to five port manifold 201 where it is distributed by regulators 210 at each port to the various parts of the system. Line 201a is distributed through 3-way valve 204 to spray ring 217. Optional switch 224 activates the optional supply of air to the ports when the tipping apparatus is inactive. Line 201b is distributed through 2-way valve 207 and two 3-port flow through 206 to the ultrasonic atomization nozzle 160 for blowing through the orifice 161g in a clearing procedure. Line 201c is distributed to the solvent reservoir 213 for pressurization. Line 213a from the solvent reservoir carries solvent such as acetone, methylethylketone, or preferably 1,1,1-trichloroethane. The solvent is used to flush residual cyanoacrylate tipping agent from the system. Line 201d carries nitrogen through 3-way valve 204 to the inert gas chamber 162. Line 201e carries nitrogen through metering system 170 and regulator 210 to pressurize the tipping agent storage bottle 212. The tipping agent is carried via line 212e through 3-port flow through 206 to the atomizing nozzle 160 where it is misted and sprayed onto a suture. Pressurized air is sent to 2-port manifold 202 and carried via line 202a through regulator 210 and 3-way valve 204 and 4-way valve 205 to power the carriage drive 214 from moving the drum mounting carriage 10. Compressed air is also sent via line 202b through a regulator 210 to a mechanism 215 for opening and closing cover panel 103. The tipping procedure is as follows. A drum assembly 26 with suture 11 wound thereon is placed onto the drum mounting carriage in the loading chamber 101 of the apparatus (See Fig. 14). The cover panel 103 is closed and the tipping sequence is initiated on the control panel 130. Compressed air powers the carriage drive 214 to move the carriage 110 and drum assembly into the processing chamber 102. As drum 26 enters chamber 102, plenum member 105 becomes disposed in notch 32 beneath the suture. As the drum assembly 26 moves under the spray head assembly 160, pressurized nitrogen at 2 psi enters the tipping solution supply to bottle 212 and moves the tipping agent to the nozzle 161 where it is atomized by sonic or ultrasonic frequency generated by the Sono-Tek unit 140. Generally a frequency of about 60 cycles is preferred although other frequencies may be selected. The tipping agent is atomized to create a cloud or mist 164 (See Figs. 17 and 18) which envelopes the sutures as they pass underneath during the traverse of drum 26 into chamber 26. Only those portions of the suture traversing the notch 32 are coated with tipping agent. As the sutures sequentially pass through the mist of tipping agent they are saturated with the agent which begins to cure in a very short period of time, typically in less than a second. The cyanoacrylate cures by polymerization catalyzed by ambient moisture. While the tipping agent is being sprayed nitrogen is blown through apertures 162b of inert gas chambers 162 to create a curtain of nitrogen gas which blows excess tipping agent from the suture 11 into plenum 105 to be drawn off under vacuum. On the return pass of drum 26 from chamber 102 to chamber 101 the suture again passes underneath the nozzle and, optionally, an additional tipping application can be made during this pass. Alternatively, several passes back and forth underneath the nozzle can be made to apply tipping agent several times. When the procedure is completed, the drum support carriage returns to the loading chamber 101, and solvent from reservoir 213 is flushed through the system to clear out residual tipping agent. Thereafter, nitrogen is flushed through the atomizing head to clear out any residual solvent. The tipping agent is preferably a solution of ethylcyanoacrylate monomer in methylethylketone (MEK). Approximately 250 milliliters of MEK is added to 248.8 g (8 ounces) of ethylcyanoacrylate to adjust the viscosity of the tipping agent to a range of from about 2 to 3 centipoise. Methylene chloride is also an acceptable solvent. Alternatively various other materials can be added to the tipping solution. For example, an bioabsorbable copolymer of glycolide and lactide may be dissolved in the tipping solution to form a biodegradable coating on the suture braids. If such an additive is employed the amount of MEK may have to be adjusted to keep the viscosity of the tipping solution within a range of about 2 to 3 centipoise. Too high a viscosity makes atomization of the tipping agent more difficult, and inhibits wicking or absorption of the tipping agent into the filaments of the braided suture. Referring to Fig. 19, the tipped portion 11a of suture 11 is usually fully polymerized and dried in about 20 to 30 seconds. Cutting The Tipped Sutures From The DrumAfter the tipping solution has polymerized, the tipped suture may be removed from the drum by cutting the tipped suture, such as with a scissors or by passing a razor or knife blade across the tipped portion to create suture segments having two tipped ends suitable for use in conjunction with a surgical needle as explained above with reference to Figs. 1 to 3. In order to facilitate controlled cutting and removal of the tipped sutures from the drum, removable drum clamps are provided to be mounted onto the drum after tipping is complete. A drum clamp 40 is illustrated in side view in Fig. 7. As explained below, suture clamp 40 is mounted to drum 26 after the suture 11 has been tipped in order to retain the suture in place during removal of the suture from the drum. Suture clamp 40 includes a main support 41 which is a U-shaped elongated member having mounting apertures 41a, as illustrated in Fig. 8. Referring again to Fig. 7, suture clamp 40 also includes dowel arm support 42 as illustrated in perspective view in Fig. 9. Dowel arm support 42 has dowel apertures 42a for receiving dowels 48 which provide means for mounting the dowel support arm to the main support 41. At least one aperture 42b on the dowel arm support accepts button screw 49a for mounting dowel arm 43 to dowel arm support 42a. Referring additionally to Fig. 10, dowel arm 43 includes an elongated aperture 43a through which button screw 49a extends for mounting to aperture 42b on the dowel arm support. Aperture 43b retains dowel 47 for mounting into aperture 35 of drum 26, as will be explained below. Suture clamp 40 further includes a rocker clamp support 44 shown in Figs. 7 and 11, which includes a knurled portion 44a, an aperture 44b for accepting a button screw 49b for mounting a rocker clamp 45, an aperture 44c for receiving a dowel 48 for mounting to main support 41, and another aperture (not shown in Fig. 11) for receiving a button screw 49c for mounting rocker spring 46 to the rocker clamp support (See Fig. 7). Referring now to Fig. 12, rocker clamp 45 includes an elongated aperture 45a for receiving button screw 49b for mounting the rocker clamp to rocker clamp support 44. The downwardly extending leg portion of rocker clamp 45 includes a hook 45b for mounting into an elongated aperture 36 in the drum, in a manner to be described below. Referring to Figs. 7 and 13, a rocker spring 46 mounts to the underside of rocker clamp support 44 by means of button screw 49c which extends through aperture 46a and into a receiving aperture in the rocker clamp support 44. The undersurface of the suture clamp 44 comprises a layer of soft resilient material 50 for contacting the suture and holding the suture to the surface of the drum 30. The preferred material for layer 50 is a silicone rubber material available from CHR Industries, New Haven, Connecticut, under the designation COHRlastic 9275. The material is preferably of low modulus (soft). The thickness of the foam can range from about 0.0762 to 1.27 cm (30 to 500 mils) and is preferably about 0.254 to 0.381 cm (100 to 150 mils). In use, after suture material 11 is wound onto drum 26 on winding apparatus 20 and the sutures have been tipped, such as by tipping apparatus 100, a pair of suture retaining clamps 40 are mounted to the drum on either side of notch 32 extending longitudinally parallel thereto, as illustrated in Fig. 21. The clamps are mounted in opposite orientation to one another, and are mounted by engaging dowel 47 into aperture 35 of drum 26 (see Figs. 6 and 7a), and thereafter engaging rocker clamp hook 45b in elongated slot or aperture 36 on the drum. Hook 46b is biased by spring 46 into engagement with elongated slot 36. With clamps 40 mounted on either side of notch 32, the tipped suture segment can be cut by knife 200 down the longitudinal length of notch 32. Because clamps 40 retain each end of the cut suture against the drum adjacent to the notch, the sutures do not fall uncontrolled away from the drum. After the suture has been cut, knurled portion 44a is pressed to overcome spring 46 and release hook 45b from slot 36, thereby releasing the cut sutures from the drum in a controlled manner. It is also contemplated that clamps 40 could be mounted onto drum 26 prior to tipping and remain in place during tipping of the sutures and removal of the tipped sutures from the drum. | A method for tipping a multifilament surgical suture characterised by the steps of: applying cyanoacrylate monomer to a selected portion of the suture, curing said cyanoacrylate monomer to adhesively bond the filaments of said suture. A method according to claim 1, wherein said monomeric cyanoacrylate is ethyl cyanoacrylate. A method according to claim 1 or 2 wherein said step of applying cyanoacrylate monomer comprises passing said selected portion of the suture through a mist of cyanoacrylate monomer. A method according to claim 3 wherein said mist is generated by sonic or ultrasonic vibration. A method according to any one of the preceding claims wherein said selected portion is a suture tip and the method further includes the step of joining said tipped suture end to a surgical needle. A method according to any one of the preceding claims wherein said suture is a coated suture. A method according to any one of the preceding claims wherein said suture is a filled suture. A surgical suture needle combination comprising a length of multifilament surgical suture having at least one end tipped with cyanoacrylate attached to a surgical needle. A suture needle combination as claimed in claim 8 wherein said surgical suture is a filled suture. A suture needle combination as claimed in claim 9 wherein said suture is filled with a glycerol-containing filler. A suture needle combination as claimed in claim 8, 9 or 10, wherein said suture is coated with at least one lubricant coating. The use of a tipping agent for multifilament suture, characterised in that the agent comprises at least one cyanoacrylate monomeric compound. A use as claimed in claim 12 wherein said cyanoacrylate monomeric compound is ethyl cyanoacrylate. Apparatus for tipping a multifilament surgical suture, which comprises means for applying cyanoacrylate monomer to a selected portion of the suture, and a suture tipping drum (26) comprising a substantially cylindrical drum configured to have suture material wound thereon and having at least one longitudinal notch (32) extending along at least a portion of the circumference of said drum. Apparatus as claimed in claim 14 wherein said drum is made having a circumferential surface of a high density plastic material. Apparatus as claimed in claim 15 wherein said high density plastic is high density polyethylene. Apparatus as claimed in claim 14, 15 or 16 further comprising suture clamping means (40) movable from a first position for holding suture material wound onto said drum against said drum surface and a second position for releasing suture material from said drum. Apparatus as claimed in claim 17 wherein said suture clamping means has a soft suture-engaging surface (50). Apparatus as claimed in claim 18 wherein said soft suture-engaging surface comprises a silicone rubber foam surface. A suture tipping apparatus (100) comprising: a supply (150) of tipping agent; which is characterised by a cyanoacrylate monomer solution; means (160) for atomizing said tipping agent to form a mist of tipping agent; and means (105) for contacting at least a portion of a suture material with said mist of tipping agent to tip said suture material with said tipping agent. Apparatus as claimed in claim 20 wherein said cyanoacrylate monomer solution has a viscosity of from about 2 to about 3 centipoise. Apparatus as claimed in claim 20 or 21 wherein said cyanoacrylate monomer solution comprises a solution of ethyl cyanoacrylate monomer in a suitable solvent. Apparatus as claimed in claim 22 wherein said ethyl cyanoacrylate monomer solution comprises ethyl cyanoacrylate monomer in methylethylketone. Apparatus as claimed in any one of claims 20 to 23 wherein said means for atomizing said tipping agent comprises an ultrasonic atomization head (160). Apparatus as claimed in claim 24 wherein said means for contacting said suture with said mist further comprises means for driving said tipping agent through said ultrasonic head to create said mist with said suture material disposed in the path of said mist. Apparatus as claimed in claim 24 or 25 further comprising solvent means (213) for flushing said ultrasonic head with solvent after tipping agent has been driven through said ultrasonic head. Apparatus as claimed in claim 26 further comprising means for driving inert gas through said ultrasonic head after said ultrasonic head has been flushed with solvent. Apparatus as claimed in any one claims 24 to 27 further comprising nozzle means (162b) adjacent to said ultrasonic head, said nozzle means being supplied with an inert gas to create a curtain of inert gas directed toward said suture material for driving excess tipping agent off said suture material. Apparatus as claimed in claim 28 wherein said inert gas is nitrogen. Apparatus as claimed in any one of claims 20 to 29 further comprising a movable tipping drum (26) configured to have suture material wound thereon, a portion of said movable drum traversing through said mist as said drum is moved from a first position to a second position. Apparatus as claimed in claim 30, or any one of claims 14 to 19, further comprising means (18) for measuring the diameter of the suture in X and Y directions as said suture is wound onto said drum, and means (13) for adjusting the tension on the suture to control the diameter of the suture wound onto said drum. | UNITED STATES SURGICAL CORP; UNITED STATES SURGICAL CORPORATION | BELLMORE HAROLD J JR; COLLIGAN FRANCIS D; PROTO GEORGE R; BELLMORE, HAROLD J., JR.; COLLIGAN, FRANCIS D.; PROTO, GEORGE R. |
EP-0490153-B1 | 490,153 | EP | B1 | EN | 19,951,102 | 1,992 | 20,100,220 | new | E05B65 | A45C13 | E05B15, A45C13, E05B65 | P05B15:02, E05B 65/52A1C | Lock assembly | A lock assembly (10, 10') for use on luggage, bags and the like has a mounting plate (15) accommodating various lock operating parts including a latch (32), a hook member (12) including a hook element (13) and an ornamental cover (16) fitted over the mounting plate (15). The latch (32) is engageable resiliently with the hook element (13) and lockable by a key (52). The ornamental cover (16) is removably connected to the mounting plate (15) and changeable from one to another with different types and designs. | This invention relates to a lock assembly for use on luggage, bags, suitcases and the like. There are known numerous lock devices of this character which have various component parts built in a lock housing. Japanese Utility Model Publication No. 34-5398 discloses a lock comprising a housing accommodating therein a locking member with a latch and a sliding member, the locking member being held in place by a helical spring, a cover fitted over the housing and a finger provided on the cover and slidably engaged with the sliding member. The locking member and the sliding member may be put in place relatively easily by pushing them into the housing, but the use of such a helical spring makes the assembly of the lock somewhat tedious and time-consuming. Another prior art lock is disclosed in Japanese Utility Model Publication No. 53-37993 which is similar to the above described prior device in that a lock member and a latch are biased in place within a housing by a helical spring. This lock further includes a guide box mounted on the housing and a knob attached to the guide box. Its various lock components are not fit for assembly by automation. Since both of the above prior art lock devices consist of a box-like housing in which lock component parts are preset, it is often necessary to change the designs or ornaments of the housing to be compatible with an article such as a bag to which the lock is secured, involving a relatively costly small lot production coupled with the fact that most of the prior locks are fabricated by press and hence have limited ornamental sophistication. US-A-3 242 705 discloses a lock assembly for luggage fittings enabling the overall size thereof to be reduced. Such a luggage fitting comprises a mounting plate 20 having a latch 46 and a cover 21 fitted thereover. A locking plate 23 includes a locking-lug 48 releasably engageable with the latch 46. A manipulating element is adapted to release a locking-lug 48. Furthermore, a key 63 is adapted for locking and unlocking. A cover 21 is a separate member connected to the mounting plate 20. A releasable connection of the separate member is not foreseen, since the mounting plate 20 and the cover 21 jointly constitute a hollow casing. DE-A-2 352 815 discloses a lock body 25 and a cover 23 fitted thereon. The lock body 25 includes a releasably engageable hook element 15 and a manipulating element 16 adapted to release hook element 15. The cover 23 is a separate ornamental member comprising a frame for receiving the lock body 25 and being provided with a recess 27 and a further recess 29. The cover 23 serves the purpose of allowing adapting the lock assembly to a variety of different containers or receptacles. The cover 23 is disclosed to have a profile form being different from that of the lock body. The connection between the lock body and the cover may be formed by bonding, clipping, clamping. According to general knowledge, clamping actions may be releasable. The lock body has a form like a cap or receptacle 26 for receiving the lock. However, such an element would render assembly of the lock very tedious, especially when changing the design of the cover, which is made by replacing one cover 23 by another cover 23. With the foregoing drawbacks of the prior art, the present invention seeks to provide a lock assembly which is suitable for a small lot production of various kinds of lock with a relatively low cost and which can be assembled with utmost ease. The invention further provides a locking assembly constructed such that its ornamental cover is replaceable from one to another to be compatible with any particular design characteristics of an article on which the lock assembly is used. As claimed, there is provided a lock assembly comprising a lock body including a mounting plate having a latch and a cover fitted over the mounting plate. The lock assembly further comprises a hook member including a hook element releasably engageable with the latch, a manipulating knob adapted to release the hook element from the latch and a key adapted to lock and unlock the lock body. According to the invention the cover is a separate ornamental member removably connected to the mounting plate. Further, the mounting plate has a first cavity section accommodating a spring member adapted to bias the hook element out of engagement with the latch. The spring provided in the first cavity section supports opening the lock assembly, i.e. it is adapted to resiliently push the hook element upward out of engagement with the latch to separate the hook member from the lock body and thus facilitates opening the lock assembly. Further, all lock component parts are accomodated in the mounting plate whereby assembly is facilitated. The above and other features and advantages of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings. Like reference numerals refer to like or corresponding parts throughout the several figures. Figure 1 is an exploded perspective view of a lock assembly according to one embodiment of the invention; Figure 2 is a view similar to Figure 1 but showing another embodiment of the invention; Figure 3 is a fully exploded perspective view of a lock mechanism of the lock assembly of the invention; Figure 4 is a perspective view of a ring member of the lock assembly; Figure 5 is a front plan view of a base plate of the lock assembly; Figure 6 is a fragmentary plan view of the base plate having a lock member and a spring member mounted therein; Figure 7 is a plan view of a sliding member of the locking assembly; Figure 8 is a cross-sectional view taken on the line VIII-VIII of Figure 7; Figure 9 is a back plan view of the sliding member; Figure 10 is a plan view of the base plate having mounted therein the spring member, the sliding member and the lock member; Figure 11 is a plan view of a casing fitted over the base plate shown in Figure 10; Figure 12 is a back plan view of an ornamental cover forming a part of the lock assembly; Figure 13 is a front plan view of the lock assembly body of the invention; Figure 14 is a cross-sectional view on enlarged scale of the lock assembly shown in unlocked condition; and Figure 15 is a view similar to Figure 14 but showing the lock assembly in locked condition. Referring now to the drawings and Figures 1 and 2 in particular, there is shown a preferred form of a lock assembly 10, (10') embodying the invention. The lock assembly 10 shown in Figure 1 is fabricated by die casting and the lock assembly 10' in Figure 2 by press, both being substantially identical in most structural details and hence identified for their common component parts by the same reference numerals. The lock assembly 10, (10') is attached to for example a bag or the like (not shown) for locking and unlocking the latter in a manner well known in the art. The lock assembly 10, (10') comprises a lock body 11 to be secured to the bag body and a hook member 12 to be secured to a cover flapper of the bag. The hook member 12 includes a hook element 13 having a latch engaging aperture 14 for receiving a latch 32 in the lock body 11 later described. The lock body 11 includes a mounting plate 15 for accommodating various lock operating members and an ornamental cover 16 having an elongate slot 17 for receiving the hook element 13 of the hook member 12, a key hole 18 for a key 52 (Figures 14 and 15) and an oblong aperture 19 for receiving a manipulating knob 60. The cover 16 is provided with a plurality of downwardly projecting pins 20 (Figure 1) or tongues 20' (Figure 2) engageable in corresponding engaging bores 21 formed in the mounting plate 15 to join the cover 16 and the plate 15 together. The tongues 20' are punched out to extend downwardly for clamping in the opening 28 and the third cavity 26 of the mounting plate 15. The mounting plate 15, after having the various lock operating parts mounted therein, is covered by a casing 22 (Figure 3) which has a plurality of fastening tabs 23 extending downwardly therefrom for securing the lock body 11 to the bag. As better shown, the mounting plate 15 is provided with a first cavity section 24 for accommodating a group of parts engageable with the hook element 13, a second cavity section 25 for accommodating a group of parts operatively associated with the key 52 and a third cavity section 26 for accommodating a group of parts operatively associated with the knob 60 and with a sliding member 27 later described. All of these component parts are expeditiously mounted in place within the respective cavities 24, 25 and 26 in a manner analogous to block building. The first cavity section 24 has a rectangular through-opening 28 bordering at one transverse edge thereof with the second cavity section 25 and at the opposite edge with a support lug 28' defining jointly with an inner transverse side wall 29 of the mounting plate 15 a transverse guide groove 30 for receiving a spring member 31 adapted to resiliently push the hook element 13 upwardly out of engagement with the latch 32 to separate the hook member 12 from the lock body 11. The spring member 31, as better shown in Figure 3, has a transverse shoulder portion 31a adapted to movably engage in the guide groove 30 of the mounting plate 15 and a pair of spaced longitudinal arms 31b extending from opposite ends of the shoulder portion 31a and disposed above the through-opening 28 in the first cavity section 24. The second cavity section 25 and the third cavity section 26 are contiguous to each other to provide sufficient space for movably supporting the sliding member 27 which as better shown in Figure 3, has a latch 32 centrally projecting between recessed shoulders 33 and adapted to engage in the latch engaging aperture 14 formed in the hook element 13. The latch 32 is brought into locking engagement with the aperture 14, as shown in Figure 10, when the sliding member 27 has moved relative to the mounting plate 15 until the shoulders 33 of the sliding member 27 come into abutting engagement with a pair of projections 34 extending inwardly from opposite longitudinal walls 35 of the mounting plate 15. In the third cavity section 26, there is provided a support plate member 36 disposed movable longitudinally horizontally relative to the mounting plate 15. The support plate member 36 includes an opening 36a for receiving a connecting pin 60a of the knob 60 through a push-nut 37 and a plurality of support pins 38 for connection with the sliding member 27 through respective pin receiving apertures 39. A meandering form of tension spring 40 is mounted on the support plate member 36 so as to normally bias the latter forwardly toward the first cavity section 24 in a direction in which the latch 32 of the sliding member 27 is brought into locking engagement with the aperture 14 of the hook member 12. Manipulating the knob 60 against the tension of the spring 40 releases the latch 32 from the aperture 14. Releasing the knob 60 in turn causes the spring 40 to bounce the sliding member 27 back toward the hook member 12. The tension spring 40 may be conveniently molded together with the mounting plate 15 through the medium of a plastics insert. Designated at 41 is a generally circular recess formed in the second cavity section 25 of the mounting plate 15 for rotatably receiving a lock hub 42 having a key groove 43 and a peripheral flange 44. The lock hub 42 is rotatably mounted in a ring member 45 having an upwardly projecting lug 46, a pair of limiters 47a, 47b extending radially outwardly in diametrically opposed relation and disposed for abutting engagement with a pair of limiter pins 48 extending in spaced relation from the second cavity section 25 and a downwardly projecting pin 49 engageable in pin-receiving holes 50 formed in the circular recess 41 in the second cavity section 25. An oblong aperture 51 is formed in the sliding member 27 in a position registering with the lock hub 42 for allowing the insertion of the key therethrough and free movement of the sliding member 27 relative to the lock hub 42. As illustrated in Figures 14 and 15, the key designated at 52 is inserted into the key groove 43 of the lock hub 42 with a horizontally extending prong 52a of the key 52 held in abutting engagement with the projecting lug 46 of the ring member 45. Rotating the key 52 thus causes the ring member 45 to rotate in one or the other direction. Rotation of the ring member 45 is limited by abutting engagement of the pair of limiter 47a, 47b with the pair of limiter pins 48 which are spaced apart by a distance such that rotative movement of the ring member 45 does not exceed an angular distance of 90° from the position in which the limiters 47a and 47b are oriented to confront the first cavity section 24 and the third cavity section 26, respectively. As shown in Figure 9, the sliding member 27 has a cam surface 53 formed internally thereof for abutting engagement with one of the pair of limiters 47a, 47b, so as to retain the sliding member 27 stationery in abutting engagement with the projections 34 of the mounting plate 15. Rotating the ring member 45 by an angular distance of 90° releases the sliding member 27. In operation, the hook element 13 is inserted into the slot 17 in the cover 16, whereupon the latch 32 is retracted and then urged back into the aperture 14 of the hook element 13 by the action of the tension spring 40. Pulling the knob 60 causes the hook element 13 to spring out under the influence of tension of the spring 31. The casing 22 has in its surface openings 54, 55 and 56 registering in position with the cavity sections 24, 25 and 26 respectively of the mounting plate 15. Lateral flanges 57 of the casing 22 are provided at spaced intervals with a plurality of engaging apertures 58 for snapping engagement with corresponding engaging lugs 59 formed in the outer longitudinal walls of the mounting plate 15. The casing 22 is thus snugly fitted over the mounting plate 15 with the lower marginal edges of the casing flanges 57 preferably flush with the lower marginal edges of the outer longitudinal wall of the mounting plate 15 as shown in Figures 1 and 2. The ornamental cover 16, when fitted over the casing 22, preferably has its lower marginal peripheral edge disposed flush with the lower marginal edges of the casing 22 so that the casing 22 is protected against flexure when thrusting the fastening tabs 23 of the casing 22 into the bag. When assembling the lock assembly 10, (10'), this is done expeditiously in a manner similar to a block building game in which the spring 31 is inserted into the groove 30 of the mounting plate 15; the lock hub 42 alone or together with the ring member 45 is placed in the recess 41 in the second cavity section 25; the sliding member 27 is fitted over the mounting plate 15; and the casing 22 is snapped into engagement with the mounting plate 15, followed by capping the ornamental cover 16 on the casing 22. Advantageously, this assembling operation can be automated since the spring members associated with the sliding member 27 are preset in the mounting plate 15. Another yet more important advantage of the invention is that since the ornamental cover 16 is a separate item for assembly, many different types and forms can be made available from a small lot production and readily changed from one to another with versatile ornaments and designs compatible with any particular bags, suitcases, luggage and the like. | A lock assembly (10, 10') comprising a lock body (11) including a mounting plate (15) having a latch (32) and a cover (16) fitted over the mounting plate (15), a hook member (12) including a hook element (13) releasably engageable with the latch (32), a manipulating element (60) adapted to release the hook element (13) from the latch (32) and a key (52) adapted to lock and unlock the lock body (11), characterised in that the cover (16) is a separate ornamental member removably connected to the mounting plate (15) and a spring member (31) is provided in a first cavity section (24) of the mounting plate (15) to bias the hook element (13) out of engagement with the latch (32). The lock assembly (10, 10') according to claim 1 characterised in that the mounting plate (15) has a second cavity section (25) accomodating a lock hub (42) engageable with the key (52) and a third cavity section (26) accomodating a spring member (40) connected to the knob (60) and adapted to normally bias the latch (32) toward the hook element (13). The lock assembly (10, 10') according to claim 1 or 2 characterised in that a casing (22) is fitted over the mounting plate (15) and provided with openings (54, 55, 56) registering in position with the first, second and third cavity sections (24, 25, 26), respectively. The lock assembly (10, 10') according to claim 2 characterised in that the lock hub (42) is mounted in a ring member (45), the ring member (45) having a pair of diametrically opposed limiters (47a, 47b) and rotatable for an angular distance of not exceeding 90° from the position in which the limiters (47a, 47b) are oriented to confront the first cavity section (24) and the third cavity section (26), respectively. | YKK CORP; YKK CORPORATION | HORITA YOSHIYUKI; TERADA YASUHARU; YOSHIMA HIROSHI; HORITA, YOSHIYUKI; TERADA, YASUHARU; YOSHIDA, HIROSHI |
EP-0490162-B1 | 490,162 | EP | B1 | EN | 19,951,108 | 1,992 | 20,100,220 | new | G21C17 | null | G21C17 | G21C 17/038, G21C 17/00B | A method and a detector for measuring subchannel voids in a light water reactor test fuel assembly | In a light water nuclear reactor test assembly for emulating the performance of a nuclear boiling water reactor fuel bundle, a system of the measurement of subchannel void fraction in the two-phase region of the emulated fuel bundle is disclosed. The emulated fuel bundle has individual emulated nuclear fuel rods typically heated by individual electrical currents instead of nuclear reaction. The interior of the emulated fuel rods are thus cylindrically hollow. A gamma-emitting source, such as americium 241, is placed on a probe and mounted for vertical excursion interior to a selected emulated hollow fuel rods. A detector, typically a Geiger-Müller counter, is placed for corresponding vertical excursion interior to another and preferably adjacent fuel rod. Gamma radiation from the source to the detector through the walls of the emulated fuel rods is measured. Attenuation of the gamma rays between source and detector is used to measure the void fraction within the two-phase region of the emulated fuel bundle. Preferably, both detector and source are collimated so that the detector does not receive gamma ray scattering from the interior of the test assembly. Preferably the detector is both collimated as to the gamma rays emitted by the source and cooled by an overlying heavy metal shield, such as gold, this shield conducting heat from the vicinity of the detector to a water-cooled line passing through the metal shield. By the expedient of utilizing a relatively low energy neutron source -- such as americium 241 with its 60 KeV gamma ray emission -- gamma signal at the detector can be directly attributed to gamma absorption of the liquid moderator fraction present between the emulated fuel rod containing the detector and the emulated fuel rod containing the source. Utilizing the disclosed test assembly an accurate measurement of the presence of moderator within a fuel bundle can be determined. | This invention relates to nuclear fuel bundles and the testing of nuclear fuel bundles in emulated fuel bundle assemblies. More specifically, an apparatus and process is disclosed for testing the moderator void fraction present between two adjacent and emulated fuel or water rods within a fuel bundle test assembly. Test loops for emulating the performance of a boiling water nuclear reactor are known. Typically, these loops are provided with electrically heated, simulator fuel rods. These fuel rods are arrayed in the same fashion as the individual fuel rods are arrayed in the interior of a nuclear reactor fuel bundle. The electrically heated individual fuel rods emulate the thermal performance of the regularly heated nuclear fuel rods containing nuclear fuel pellets undergoing fission reaction. Electric current is typically applied to the individual test fuel rods to heat the rods in a manner that is precisely analogous to the heating that would be applied by the nuclear fuel in the presence of moderated neutrons. Such test assemblies (bundles) are mounted in a so-called test loop. The test loop supplies water moderator at the temperature, pressure and flow rate that are encountered in a nuclear reactor. Such water moderator is supplied to the bottom of a vessel containing the nuclear fuel bundle test assembly, where it attains boiling conditions as it flows between the electrically heated fuel rods. When water is circulated from the bottom of such a test vessel out through the top of such a test vessel, the actual operation of a nuclear fuel bundle within a boiling water nuclear reactor can be closely emulated. Boiling water reactors fuel bundles are comprised of elongate assemblies of individual fuel rods standing in a matrix in an upright position. Such matrices vary in density from 8 x 8 arrays to 9 x 9 arrays to 10 x 10 arrays presently. In the lower portion of such nuclear fuel bundles, only the liquid water moderator is present. In the upper portion of such nuclear fuel bundles, a combination of liquid moderator and steam is present. As the water passes through the fuel bundle from the bottom to the top, an increasing fraction of the passing water is in the form of steam. Consequently, it is said that the upper portions of such bundles have an increasing void fraction within the fuel bundle. That is to say, fuel bundles have increasing concentrations of steam and decreasing concentrations of liquid as the water moderator passes upwardly along their length. Boiling water nuclear reactors are dependent upon this void fraction in their operation. This dependency occurs as a result of two discrete phenomena. First, the reactors require that the individual fuel rods effect efficient and so-called nucleate boiling of the water. This nucleate boiling is necessary not only for the generation of steam, but also for insuring that the individual fuel rods are not damaged by overheating. During the nuclear reaction, the sealed individual fuel rods of the fuel bundle constitute heated pressure vessels for the retention of their contained radioactive materials. If the individual fuel rods are not maintained in a cooled state, overheating of the fuel rods can cause damage to the exterior of the individual fuel rods. The onset of this overheat is commonly known as boiling transition or dryout and is characterized by an increase in temperature at the boiling surface. Naturally in efficient and safe nuclear design and operation, the avoidance of the onset of boiling transition is highly desirable. Secondly, boiling water nuclear reactors are dependent on the amount of moderation present to maintain the desired nuclear reaction. Simply stated, the fission reaction in such boiling water nuclear reactors generates fast-moving or high speed neutrons. In order for these fast-moving or high-speed neutrons to take part in the continuing and desired fission reaction, the neutrons must be slowed or moderated to the thermal state. Such slowing occurs in the water moderator and is dependent upon the density of hydrogen atoms of the moderator. Since the density of hydrogen atoms at BWR condition is about twenty times greater for the liquid than for the steam vapor phase, it is vital to know and understand the liquid fraction that is present at all parts of a fuel bundle. Test assemblies utilizing electric heating to emulate the performance of all or a portion of a nuclear fuel bundle undergoing nuclear reaction are known. These known test assemblies usually include a plurality of hollow emulated fuel rods. These hollow or emulated fuel rods are given a diameter analogous to the diameter of the fuel rods being emulated. Current is applied across the rods to generate heat at the same rate that a nuclear reaction, interior of the real fuel rods, would generate heat. Such fuel rods are installed within a test loop. The test loop emulates the pressure and temperature conditions found within a nuclear reactor. Specifically, heated water is introduced at bottom of such emulated fuel bundles. Water and steam is extracted from the top of such emulated fuel bundles. Flow is maintained through the fuel bundles in precise analogy to that encountered within the nuclear reactor. Typically, and because nuclear reactors operate under high temperatures and pressures (usually 6.895x10⁶ Nm⁻²(1,000 pounds per square inch) of pressure at 273.9°C (525° F) inlet), such test assemblies are placed within a substantial containment vessel. This vessel contains the moderator under the desired pressure, temperature and flow conditions. At the same time, all access for the measurement of moderator must be obtained through the containment vessel. It has been known in the past to measure void fractions across all or a substantial portion of a nuclear fuel bundle in such test assemblies. Usually, a group of emulated fuel rods comprising less than a full fuel bundle and on the order of one-quarter of a fuel bundle is utilized. This partial bundle of fuel rods is enclosed within a test loop that maintains within a pressure vessel the full temperature, pressure and flow conditions that can be encountered within the boiling water nuclear reactor. Measurement of the void fraction has occurred in the past through the walls of the containment vessel. Such measurement occurs from one side of all of the emulated fuel rods within the containment vessel to the other side of all of the fuel rods within the containment vessel. Specifically installed windows of low material density are required to enable this testing to occur. Further, and when there is an emulated channel box in place surrounding the fuel bundle test assembly, it is necessary also to provide the channel box in the test assembly with corresponding windows. These corresponding windows in the emulating channel box are registered to the window in the containment vessel. In the past, a gamma emitter has been utilized for the measurement of void fractions across such test assemblies. Because of the thickness of such test assemblies, the gamma source chosen is required to have sufficient emission energy to pass through the vessel windows, the channel box windows and across the full width of the assembly being tested. At the other side, the gamma signal must pass through the opposite channel box windows and the pressure vessel windows. In such passage, the variation in the attenuation of the gamma rays is relied upon to indicate the presence or absence of water moderator in the path between source and detector. Unfortunately, and with such an across the test assembly gamma ray penetration, it is not always possible to determine with precision where the attenuation of the gamma rays originates. First, the interrogating gamma radiation must traverse relatively long distances. Second, the fuel rods in such assemblies (and indeed in all nuclear fuel assemblies) do not achieve perfect vertical alignment in their row and column orientation. It is known that some fuel rods wander out of alignment relative to the remaining fuel rods. As a result, the attenuation of the interrogating gamma rays for the determination of void fraction can encounter many variations from passage across the test assembly that are due to factors other than the presence or absence of moderator. Finally, and assuming that the attenuation of moderator in such assemblies is due solely to moderator present, there is a difficulty in determining where the moderator resides that causes the attenuation. For example, it is well known that liquid moderator coats the inside of the channel box walls within a nuclear fuel bundle. Unfortunately, and in a scan completely across a nuclear fuel bundle, discrimination of that fraction of moderator adjacent the channel wall from that fraction of moderator at other portions of the bundle is generally not possible. Further, it will be remembered that in a boiling water reactor, moderator fraction resident in the fuel bundle changes both with respect to the power level and the particular height of interrogation across the fuel bundle. Heretofore, examination of the fuel bundle at differing heights to determine moderator fraction has not been possible because of the required location of windows to permit access of the gamma radiation. The present invention is specified in the claims to which attention is directed. An embodiment of the invention provides, in a test assembly for emulating the performance of a nuclear boiling water reactor fuel bundle, a system of the measurement of subchannel void fraction in the two-phase region of the emulated fuel bundle. The emulated fuel bundle has individual emulated nuclear fuel rods typically heated by individual electrical currents instead of nuclear reaction. The interior of the emulated fuel rods are thus cylindrically hollow. A gamma-emitting source, such as americium 241, is placed on a probe and mounted for vertical excursion interior to a selected emulated hollow fuel rods. A detector, typically a Geiger-Müller counter, is placed for corresponding vertical excursion interior to another and preferably adjacent fuel rod. Gamma radiation from the source to the detector through the walls of the emulated fuel rods is measured. Attenuation of the gamma rays between source and detector is used to measure the void fraction within the two-phase region of the emulated fuel bundle. Preferably, both detector and source are collimated so that the detector does not receive gamma ray scattering from the interior of the test assembly. Preferably the detector is both collimated as to the gamma rays emitted by the source and cooled by an overlying heavy metal shield, such as gold, this shield conducting heat from the vicinity of the detector to a water-cooled line passing through the metal shield. By the expedient of utilizing a relatively low energy neutron source -- such as americium 241 with its 60 KeV gamma ray emission -- gamma signal at the detector can be directly attributed to gamma absorption of the liquid moderator fraction present between the emulated fuel rod containing the detector and the emulated fuel rod containing the source. Utilizing the test assembly, an accurate measurement of the presence of moderator within a fuel bundle can be determined. An object of an embodiment of this invention is to provide a measurement technique for determining the density of moderator between discrete emulated fuel rods within a fuel bundle test assembly. According to this embodiment of the invention, a radioactive source is chosen having a moderate gamma ray emission. For example, a source including americium 241 includes a decay emitted 60 KeV gamma ray. Typically the gamma ray source is mounted within an electrically heated emulated nuclear fuel rod. A Geiger-Müller counter is placed interior of an adjacent discrete test fuel rod, both such rods being disposed within the nuclear fuel bundle test assembly. Preferably both the source and detector are surrounded with collimation shielding with the result that the receipt of scattered gamma ray radiation at the detector is minimized. As the power level in the test fuel bundle is changed, the attenuation of gamma radiation between the source and detector can be used to determine the moderator void fraction present between the individually monitored and emulated fuel rods. An advantage of this embodiment of the invention is that measurement is made directly between discrete and adjacent fuel rods within the nuclear fuel bundle test assembly. As a consequence, the absence or presence of moderator is a direct effect of the void fraction in the moderator adjoining the path between the two adjacent fuel rods. Other fractions of moderator - such as those known to be present adjacent the channel box walls of the emulated fuel bundle - are not measured. An additional advantage of this embodiment is that a relatively low-energy gamma source can be utilized. This low-energy gamma at the gamma source -- americium 241 with its decay gamma emission of 60 KeV -- has an ideal intensity for measurement of the changes in moderator fraction across two immediately adjacent emulated fuel rods. As a consequence, a higher intensity gamma source having energy to effect measurement across the entire width of a fuel bundle assembly, is not required An additional embodiment of this invention provides a Geiger-Müller detector which can tolerate the relatively high heat environment of an emulated fuel rod within a nuclear fuel bundle test assembly. According to this embodiment of the invention, the Geiger-Müller detector is surrounded by a gold collimating shield. This shield in turn is communicated to a cooling water source. The interstitial volume between the counter and shield on one hand, and the inside diameter of the emulated fuel rod on the other hand, is surrounded by a thermal insulator, preferably a ceramic paper. During measurement, a continuous flow of cooling water passes around the Geiger-Müller counter shielding. Protected by the insulation, shielding and coolant water flow, the detector can operate within the high temperature environment of the emulated fuel rod assembly. An advantage of the embodiment is that both the americium 241 source and the Geiger-Müller counter are small. Accordingly the source and detector can easily fit within the increasingly small fuel rod diameters utilized in modern nuclear fuel bundles. For example, individual fuel rods in 10 x 10 fuel rod arrays typically have an interior diameter of 914 mm (0.36 inch). The source and detector assemblies can easily fit within such a dimension. An additional advantage of an embodiment of this invention is that no longer must measurement be made through the wall of a vessel containing the fuel bundle test assembly. Instead the measurement can be effected by direct insertion of the detector and probe from below the assembly. Direct access to the test fuel rod site to be examined for moderator is provided. An embodiment of the invention enables vertical excursion of both source and detector in a nuclear fuel bundle test assembly. According to this embodiment of the invention, a common carriage is provided for the vertical excursion along a path immediately underlying the fuel bundle test assembly. The fuel bundle test assembly is constructed so as to provide downward exposed openings in each of the individual emulated fuel rods forming the construction of the fuel bundle test assembly. Typically, the radioactive source is registered to and inserted in one emulated fuel rod. One or more detectors is registered to and inserted in one or more adjacent emulated fuel rods. The source and detectors are moved in elevation interior of their respective fuel rods, simultaneously. Utilizing this movement in elevation, readings can be taken at all effective elevations in the two-phase region of the emulated fuel bundle. As a result there is provided, for the first time, a method and apparatus for determining void fractions at all elevations within the fuel bundle. A better understanding of this invention will be more apparent after referring to the following specification and attached drawings in which: Fig. 1 is the side elevation section of a schematic of a test loop for testing the performance of a fuel bundle, the loop here illustrating a test unit capable of testing a full fuel bundle including a fuel channel; Fig. 2A is a side elevation section detail of a gamma ray source, the source shown being an aligned source of americium 241 surrounded by a gold layer for effecting collimation of gamma rays emitted at the source; Fig. 2B is a side elevation section of a Geiger-Müller tube illustrating the tube surrounded by shielding for conducting the heat away from the detector assembly as well as collimating the received gamma radiation; Fig. 2C is a plan section of the Geiger-Müller tube of Fig. 2B taken medially of the tube illustrating the termination of the collimator and cooling fin; Fig. 3 is a plan section of the test assembly taken along lines 3-3 of Fig. 1 illustrating an exemplary moderator density measurement that can be taken; Fig. 4 illustrates an assembly below the fuel bundle test assembly for raising and lowering the source and detector in selected tubes of the fuel bundle assembly being tested; and, Fig. 5 illustrates the lower end of the detector probe and its construction for accommodating variable expansion of the detector probe as insertion changes within the nuclear fuel bundle test assembly. Referring to Fig. 1, a vessel V is shown mounted between an upper flange assembly 14 and a lower water-inlet assembly 15. Interior of the vessel V there is mounted a channel C having a plurality of fuel rods R. The fuel rods R all extend between a ground bus 20 and an electrically hot bus 22. Individually, each of the fuel rods R is provided with electrical current. In operation, water flow through the vessel V and individual electric current to each of the rods R is varied. Such variation occurs to emulate in the test assembly the same conditions that occur within a nuclear fuel bundle. For example, at inlet 15 to vessel V, water flows inwardly at approximately 6,9x10⁶ Nm⁻² (1000 psia) pressure and at 274°C (525°F). Similarly and outwardly through the top of the pressure vessel V at 17, water and steam flow out. By changing the respective current rates on each of the individual rods R emulation of fuel bundle at all powering rates can occur. Referring to Fig. 2a, an enlarged detail of Fig. 1 is illustrated taken along lines 2a-2a of Fig. 1. Specifically, the end of a probe P1 is disclosed. Probe P1 has mounted on top thereof a source capsule 30, the mounting here occurring through a threaded connection schematically illustrated at 31. Approximately 10mCi activity of americium 241 is arrayed within the source mounting 30. Typically the americium 241 is arrayed as a line source shown at 34 and is surrounded by peripheral shielding at 35 so as to expose a rectangular window. A material sufficient for both shielding and withstanding temperatures has been found to be gold. It will be remembered that the perimeters of the respective rods, here rod R1, are under a considerable electrical potential. This being the case, the entire assembly is enclosed within an insulating layer of Teflon 38. Preferably the entire test assembly is maintained at ground potential through a conductor of suitable electrical resistance. Referring to Fig. 2b, the detector D of this invention is illustrated. A state of the art Geiger-Müller tube 40 is mounted centrally of the detector. This Geiger-Müller tube is surrounded by thermally conductive shielding 42 which effectively collimates gamma radiation received interior of the Geiger-Müller tube 40. The shielding is, in turn, surrounded by a cooling water tube 44 which supplies a continuing flow of water as indicated by arrows 46. Gold is used for the disclosed shielding; it can effect collimation of the gamma radiation and conduction of heat. Exterior of the Geiger-Müller tube there is provided an insulation layer. A preferred layer of thermal insulation 48 has been found to be ceramic paper. Such a paper insulation is sold by the Cotronics Corporation of Brooklyn, New York, under the catalog designation 300-020. (It will be understood that the purpose of the ceramic paper insulation and water cooling is to insure that the gold shield, and the detector inside it, remain cool.) Geiger-Müller counter 40 is of standard construction; typically, it is connected via an anode resistor 49 to a coaxial cable, to the preamplifier 78, Fig. 4, the monitor being a standard state of the art monitor which will not be further described herein. (The monitor is not in or near the probe. It is remotely located.) Precisely analogous to the case of the source, the entire detector assembly is surrounded by a layer of Teflon insulation 50. As it will be remembered that the heater tube includes electric potential, such insulation is required. It will be known to the reader that the individual fuel rod through which observation takes place, here the rod R2, can also be provided with insulation. Typically such tubes include ceramic insulation in the interior thereof. It will be appreciated that any breakdown in this insulation will expose a high electrical potential. Accordingly, it is customary to maintain both source and detector probes at ground potential through a conductor of suitable electrical resistance. In the event that any potential is read, it is presumed that insulation breakdown has occurred. Removal and repair of the source and detector is immediately made to prevent electrical potential from two locations burning out or otherwise destroying the source and detector. Referring to Fig. 3, a fuel bundle having an exemplary fuel rod array is illustrated. The vessel V of Fig. 1 is illustration at the section 3-3. The assembly includes an individual channel C and numerous rods R. Assuming that the americium source S is passed interior of a rod Rs possible placements of the detector for measurement are shown. For example, such placements of the detector can include an immediately adjacent rod 60, a diagonally adjacent rod 61 or other selected fuel rods. Further, measurement to and across gaps created by so-called partial length rods can be made. By way of example, it can be seen that source S can measure the moderator fraction along a path directly overlying the top of a partial length (not shown in the view here illustrated), to rod 63. It will likewise be appreciated that both a probe carrying the source and a probe carrying the detector can be registered to any of the numerous rods illustrated in the view of Fig. 3. For purposes of this application, only one probe and one detector have been illustrated. It will be understood that multiple probes and multiple detectors can be utilized. Referring to Fig. 4, the lower end of the vessel V is shown. It will be remembered that each of the respective rods R is downwardly exposed to and towards the bottom of the disclosed fuel bundle test assembly. A probe base B is shown. Base B is arranged for vertical excursion on a track T having a guide G fitted within a well bore W. A motor including a chain 72 and sprocket drive 70 raises and lowers the probe base B. To the probe base B, there are fixed probe P1 mounting the source and probe P2 mounting the detector. In order to assure communication of the detector to both monitoring instrumentation and a source of coolant, depending lines L connect the base B and an instrumentation preamplifier 78. Conduit to test instrumentation (not shown) extends from the preamplifier. It will be understood, that as probe P2 effects varying degrees of penetration within any of the rods R of the nuclear fuel bundle test assembly, differential expansion of the probe will occur. Accordingly, and to accommodate this expansion, the inlet cooling water is fed from a coil 80, which coil 80 expands and contracts corresponding to the variable expansion and contraction of the probe P2 upon its penetration and elevation interior of the rod R in which detection is occurring. Accordingly, base B is provided with a probe coil of extra length which coil can extend differentially the length of the probe. Discharge occurs by means of a simple tube spraying heated coolant downwardly. Operation of the probe is easy to understand. Specifically, both source and detector are scanned in elevation during steady state operation of the test vessel illustrated in Fig. 1. During such scans, changes in gamma radiation detected are related directly to the moderator void fraction present between adjacent fuel bundles. It will be appreciated that the disclosed technique is a powerful one. By way of example, the exact distribution of moderator can be determined by modeling. For example by modeling the predicted distribution of moderator and comparing the model to determine experimental results, varying distribution of moderator including the moderator adjacent the channel walls can be determined. | A nuclear fuel bundle test assembly having: a plurality of upstanding vertical rods (R), said rods having an outside diameter the same as the outside diameter of fuel rods within a nuclear fuel bundle; a lower support plate (20) for supporting said vertical rods and providing current to the lower end of said vertical upstanding rods, said lower support plate exposing the lower open ends of said vertical upstanding rods to enable the entrance and exit of testing probes to the interior of said vertical upstanding rods; an upper support plate (22) for maintaining said rods in vertical upstanding relation and providing current to the upper end of said vertical upstanding rods; a power source connected across said upper and lower support plates for supplying power to said test assembly to produce heat at said individual upstanding rods; a test chamber (C) surrounding said vertical upstanding rods for permitting inflow (15) of water at the bottom of said rods and the outflow (17) of water and steam at the upper end of said vertical upstanding rods to enable said test assembly to emulate a nuclear fuel bundle, said test assembly being characterised by: first and second probes (P1, D) for vertical excursion interior of first and second upstanding vertical rods; a radioactive source (30) mounted to one (P1) of said probes, said radioactive source emitting particles attenuated by passage through water; a detector (40) mounted to the other (D) of said probes, said detector for measuring radioactive particles from said source arriving at said detector; and, means (T, G, 70, 72) for raising and lowering said first and second probes in selected upstanding vertical rods for the measurement of moderator fraction between said upstanding tubes. The test assembly of claim 1 wherein said radioactive source is collimated. The test assembly of claim 2 wherein said detector is collimated. A method for the measurement of the void fraction between individual rods of a nuclear fuel test bundle assembly having: a plurality of hollow, electrically heated tubes, said tubes each having an outside diameter equal to the outside diameter of actual fuel rods within an actual nuclear fuel bundle assembly; a vessel for containing said plurality of hollow electrically heated tubes, said vessel permitting the inflow of water at the bottom and the outflow of water and steam at the top to emulate an actual nuclear fuel bundle in the generation of steam from water during the upward passage of water within said fuel bundle, said method comprising the steps of: providing a radioactive source, said source emitting radioactive particles having sufficient energy for passage through said tube walls, and across the water between said tubes to enable water between said tubes to attenuate emitted radiation in proportion to the liquid fraction present between said tubes; providing a radioactive detector, said detector for receiving and detecting radioactive particles emitted from said source and passing through said water; inserting said source in a first of said tubes; inserting said detector in a second of said tubes to the same elevation as said source; and measuring said radiation from said source to said detector to determine the water fraction between said tubes. The method of claim 4 comprising the step of: elevating said source and said detector to the same elevation to determine the water fraction between said tubes at all elevations in said vertical upstanding electrically heated rods. A detector for insertion to an electrically heated tube within a nuclear fuel bundle test assembly, said detector comprising in combination: a Geiger-Müller counter; a conducting and shielding material (42) surrounding said Geiger-Müller counter, said material having a window therein for permitting collimated radiation to be received to said counter; a source of coolant (44) thermally communicated to said Geiger-Müller counter for cooling said conducting and shielding material; thermal insulation means (48) for surrounding said Geiger-Müller counter for permitting said counter to pass through and into a heated environment at temperatures below said heated environment; and electrical insulation means (50) for surrounding said Geiger-Müller counter for preventing electrical potential within said electrically heated tube from energizing said detector. | GEN ELECTRIC; GENERAL ELECTRIC COMPANY | MATZNER BRUCE NMN; SHIRAISHI LEROY MASAO; WILHELMSON DONALD ALLEN; MATZNER, BRUCE (NMN); SHIRAISHI, LEROY MASAO; WILHELMSON, DONALD ALLEN |
EP-0490166-B1 | 490,166 | EP | B1 | EN | 19,950,913 | 1,992 | 20,100,220 | new | G01J5 | G01J5 | G01J5, G01J1, F25D19, H01L31 | G01J 5/06B, F25D 19/00C, H01L 31/024 | Quick cooldown/low distortion hybrid focal plane array platform for use in infrared detector dewar packages | A radiation detector assembly (20) includes a radiation detector (2), a silicon readout device (3) coupled to the radiation detector (2), and a platform (13) for supporting from a first major surface (13a) the readout device (3) and the radiation detector (2). A second major surface (13b) includes a boss (14) for coupling, via an active brazing operation, to a cryogenic cooler (10). The platform (13) is a monolithic structure comprised of Aluminum Nitride (AlN). | This invention relates generally to focal plane array (FPA) support and cooling apparatus and, in particular, to hybrid FPA support and cooling apparatus that includes a one piece FPA platform. In a presently preferred embodiment, a monolithic FPA platform is comprised of Aluminum Nitride (AlN) because of this material's properties relating to a thermal contraction characteristic, elastic modulus, dielectric properties, and the enablement of advanced brazing operations that result in a hermetically sealed vacuum enclosure. Fig. 1 illustrates in cross-section an exemplary prior art radiation detector dewar assembly 1. A hybrid FPA (HFPA) includes a radiation detector array 2 that is coupled to a read-out device 3. By example, the radiation detector array 2 is comprised of HgCdTe, the read-out device 3 is comprised of Si and the two are joined by Indium bump technology. The read-out device 3 is mounted to an electrically insulating fanout board 4 upon which electrical conductors are distributed and provided, via wiring 5, to interface pins 6 which exit through a backwall 7. In this regard the fanout board is typically comprised of an alumina disk having thin film gold metalization for defining the required electrical conductors. Fanout board 4 is also coupled to a coldshield 8 and to an endcap 9, comprised typically of Invar 36, at which a coldfinger assembly 10 terminates. The coldfinger assembly 10 provides for a cryogenic cooling medium, such as liquid nitrogen, to contact the endcap 9 for cooling the detector array 2 and the coldshield 8. An outer housing 11 supports a transparent window 12 and provides a hermetically sealed vacuum enclosure; the inner volume of the assembly 1 typically being evacuated prior to use. During fabrication, the relatively thick metal endcap 9 is first brazed to the coldfinger assembly 10 using conventional braze techniques wherein the surfaces to be joined are first given a nickel, or equivalent, metallic coating. To this structure an intermediary platform, the fanout board 4, is adhesively joined. The fanout board 4 provides a stiff and thermally conductive support for the HFPA. The HFPA, through a back surface of the Si readout device 3, is adhesively bonded to the fanout board 4. The use of this prior art structure presents several problems relating to the fanout board 4 and the structures attached thereto. For example, the fanout board is typically comprised of a ceramic material, such as alumina, in order to provide adequate dielectric properties. However, the ceramic material typically will have a less than optimum thermal diffusivity which results in an appreciable amount of required time to cool the HFPA to cryogenic operating temperatures. Furthermore, the adhesive bonds between the fanout board 4 and the readout device 3 and the coldfinger assembly 10 present additional thermal barriers to rapid cooldown. Also, the ceramic material of the fanout board 4 provides a less than optimum match to the thermal contraction characteristic of the Si readout device 3. As a result, stresses may be generated between the fanout board 4 and the readout device 3 when cooled to cryogenic operating temperatures. These stresses may cause distortion that can adversely affect the Indium bump coupling to the detector array 2 and can result in a total failure of some of the bumps. Additional disadvantages relate to the multi-piece construction of the fanout board 4/endcap 9 assembly and the use of adhesive as a joining element. This adhesive joint may be susceptible to the outgassing of organic species, thereby compromising the vacuum integrity of the dewar assembly 1. US-A-4 952 810 dislcoses an infrared detector assembly including a tubular coldfinger which is surrounding by a vacuum and an endcap mounted to the coldfinger tube to define a cold end which supports the infrared detector array and related components. According to this prior art document, the coldfinger tube is a thin-walled titanium cylinder and the endcap is made of tungsten. The components are metallurgically bonded at the cold end by an active brazing alloy deposited during vacuum furnace brazing. The titanium coldfinger provides the necessary bending stiffness to support cold end components. The endcap comprises a platform which is integral with boss upstanding therefrom and made from tungsten. The infrared detector array is associated with wiring penetrating a mounting flanch at feed-through ports. From EP-A-0 304 142 a semiconductor device comprising a silicon chip semiconductor element and a package including outer lead wires for external connection is known. The known package may be used in an infrared ray detector used in a cryogenic temperature and comprises a bottom plate to which the semiconductor element is bonded, a frame-shaped intermediate plate and a top plate attached to the intermediate plate, thereby defining therein a closed space in which the semiconductor element is mounted. The bottom plate and the top plate are made of a material which has substantially the same coefficient of thermal expansion as that of the semiconductor element, namely from aluminum nitride or silicon carbide. From US-A-4 954 708 an infrared detector assembly is known which comprises a ceramic mounting board upon which a predefined pattern having a plurality of gold traces is vapor deposited for conducting electrical signals generated by a hybride detector to external control electronics. It is an object of the invention to overcome limitations of conventional radiation detector dewar assemblies. It is a further object of the invention to provide a monolithic fanout board/endcap assembly having a characteristic of thermal expansion and contraction that is similar to that of a silicon readout device, that furtherthemore exhibits a high thermal diffusivity for achieving a rapid cool down time, and which furtherthemore enables the elimination of the conventional adhesive joint to a coldfinger assembly through advanced brazing techniques. The foregoing and other problems are overcome and the objects of the invention are realized by a radiation detector assembly according to claim 1 and by a method of fabricating a portion of a radiation detector dewar assembly according to claim 12. The radiation detector assembly according to the invention comprises a one piece, low distortion, hybrid focal plane array platform which functions as an integral coldshield support, detector signal fanout board, and critical thermal interface between a dewar cooling device, either cryostat or cryoengine, and a FPA. According to the invention the platform is comprised of Aluminum Nitride (AlN). AlN provides a unique combination of preferred material characteristics that are well suited for a detector dewar application. These properties include the following. AlN provides a higher thermal diffusivity, relative to many ceramic materials, for providing a reduced cooldown time of an infrared detector to cryogenic temperatures. AlN has a 300K-77K thermal contraction characteristic that closely matches that of a silicon readout device. AlN also has an elastic modulus that results in a high degree of stiffness for reducing distortion of the Si readout device. These characteristics increase dewar reliability by minimizing thermal stresses on Indium bumps and reducing distortion of the readout device. Furtherthemore, AlN has dielectric characteristics that permit thin film metalization of the surface for providing electrical signal distribution, thereby eliminating a requirement for the conventional ceramic fanout board. In addition, the integral AlN endcap/AlN platform may be hermetically brazed to the coldfinger assembly without requiring costly metalization techniques required for conventional brasing operations. Also, the monolithic platform/endcap construction made possible by the invention eliminates at least one adhesive bond within the dewar, thereby reducing the potential for outgassing organic species that comprise the vacuum life of the dewar assembly. According to the invention the platform comprises a first major surface having a patterned thin metalization film for coupling the readout device to electrical terminals. The metalization film comprises a first layer of titanium, to promote adhesion to the aluminum nitride, and at least a second layer of highly conductive material deposited thereon, preferably a gold layer. The above set forth and other features of the invention are made more apparent in the ensuing Detailed Description of the Invention when read in conjunction with the attached Drawing, wherein: Fig. 1 is a cross-sectional view of a conventional radiation detector dewar assembly; Fig. 2 is a cross-sectional view of a radiation detector dewar assembly constructed in accordance with the invention; Fig. 3 is a front view, not to scale, of the FPA platform showing a portion of the thin-film metalization applied to the front surface; Fig. 4 is a side view of the FPA platform; and Fig. 5 is a back view of the FPA platform. Referring to Fig. 2 there is illustrated in cross-section, not to scale, a radiation detector dewar assembly 20 constructed in accordance with the invention, wherein reference numerals in common with Fig. 1 indicate identical structure. In Fig. 2 the fanout board 4 and endcap 9 of Fig. 1 are replaced by a one piece monolithic platform 13. Platform 13 is comprised of, in a presently preferred embodiment of the invention, AlN (mol. wt. 40.99, Al 65.82%, N 34.18%). Of course, the AlN material may also contain binders and other additives so long as the desirable material properties of AlN, described below, are not significantly compromised. Referring now also to Figs. 3, 4 and 5, in the illustrated embodiment platform 13 has a generally circular disk shape having a planar front surface 13a for mounting the Si readout device 3 and a protruding extension or boss 14 on a back surface 13b. The protruding boss 14 functions as a structural, vacuum, and thermal interface to the coldfinger tube 10. That is, the boss 14 functions as the metal endcap 9 of Fig. 1. The platform 13 may be fabricated by machining a block of AlN to the desired shape or may be cast in the desired shape. Of course, other than a generally circular disk shape may be provided. By example, the platform 13 has a thickness (T) of approximately 0.508 mm (0.02 inches) and a diameter (D) of approximately 19.05 mm (0.75 inches). The height (H) of the boss 14 from the back surface 13b is approximately 0.508 mm (0.02 inches), the boss 14 having a diameter (Db) of approximately 8.89 mm (0.35 inches). These dimensions are exemplary only and, in practice, the AlN platform 13 may be fabricated to any desired shape and dimensions. The use of AlN as the platform 13 material provides the following significant advantages in the construction and operation of the radiation detector dewar assembly 20. An improvement in cooldown time is achieved because of reduced platform thickness and the elimination of thermal interfaces, as compared to the prior art. For example, the adhesive joint between the endcap 9 and the fanout board 4 of Fig. 1 is eliminated in that the equivalent structure is provided in the monolithic shape of the platform 13. Also, AlN exhibits an inherently high thermal diffusivity as compared to the prior art materials. The 300K to 77K integrated thermal diffusivity of AlN is approximately three times that of the prior art alumina fanout board 4. The elimination of an extra piece part and related processing steps is achieved by combining the detector platform with the fanout board 9. In that the AlN platform 13 exhibits good dielectric characteristics the surface 13a may also be patterned and thin film metalized to form the conductors for coupling to the HFPA. The platform 13 thus functions as the fanout board, thereby eliminating the need for an additional alumina metalized mounting board with its associated thermal mass and thermal interface. A portion of the thin film metalization is shown in Fig. 3. The thin film metalization may be comprised of a thin layer of titanium, to promote adhesion to the AlN, and a relatively thicker layer of gold overlying the titanium. The HFPA is wire-bonded to the metalization as in the prior art structure of Fig. 1. The HFPA is attached directly to the AlN platform 13 using an adhesive. The coldshield 8 is also adhesively bonded to the surface 13a using, for example, a silicone-based adhesive. Also achieved through the use of the AlN platform 13 is an improved detector readout reliability because of the close match between the 300K-77K thermal contraction characteristics of Si and AlN. For example, the 300K-77K thermal contraction characteristic of AlN is on the order of 0.32 mm/m (0.32 mils/inch) while that of Si is on the order of 0.26 mm/m (0.26 mils/inch) over the same temperature range, whereas the prior art alumina platform material has a value on the order of 0.73 mm/m (0.73 mils/inch) over the same temperature range. As can readily be seen, the prior art alumina platform has a contraction characteristic nearly three times that of silicon while AlN differs by only several percent. This relatively close match results in reduced thermal stress between the FPA platform 13 and the readout device 3. Also, the elastic modulus, on the order of 40 X 10⁶, of AlN provides a high stiffness minimizing any distortion of the readout device 3. Although the elastic modulus of alumina is on the order of 50 X 10⁶, the other inferior properties of this material, such as the larger thermal contraction characteristic and lower thermal diffusivity, make AlN a superior material for use in cryogenic dewar applications. Another significant advantage conferred by the use of the invention is that state-of-the-art active metal brazing techniques may be employed to hermetically braze the platform 13 onto the end of the lower vacuum assembly. The platform 13 brazement is accomplished using an active braze alloy. The active brazing of ceramic material is described in an article entitled High Reliability Joining of Ceramic to Metal , American Ceramic Society Bulletin, Vol. 68, No. 9, pages 1591-1599, September 1989 by H. Mizuhara et al. For the active brazing operation the conventional sputter metalization of, by example, titanium-nickel followed by a nickel plate is avoided, thereby further reducing manufacturing cost. Also, vacuum life is extended by elimination of the adhesive joint interface at the endcap/platform of Fig. 1. That is, the AlN platform 13 is directly brazed to the coldfinger tube 10 thereby reducing the possibility of vacuum failure due to outgassing of organic species from the adhesive joint required by the prior art to join fanout board 4 to the endcap 9. This furthermore results in lower overall manufacturing costs because of the elimination of the separate platform/endcap pieces and the required bonding operation. Also, the platform 13 constructed in accordance with the invention does not preclude the use of either cryostat or cryoengine cooling devices. The active brazing operation is accomplished to join the AlN platform 13, specifically the boss 14, to the end of the coldfinger tube 10. Prior to joining the two assemblies an active brazing alloy, such as Cusil-ABA (available from Wesgo of Belmont, CA) is applied about the boss 14. The boss 14 is inserted into the end of the coldfinger tube 10 and the two assemblies are placed in a vacuum furnace and heated to approximately 1600o F for approximately five minutes. When removed from the furnace a hermetic braze joint is found to be established between the AlN platform 13 and the coldfinger tube 10. Active brazing is a presently preferred technique due to the difficulty in providing a metal adhesion layer for braze purposes onto insulating materials, such as the AlN material, prior to a conventional brazing operation. Furthermore, the elimination of the conventional required metal plating operations results in increased manufacturing efficiencies and cost savings. While the invention has been particularly shown and described with respect to a preferred embodiment thereof, it will be understood by those skilled in the art that changes in form and details may be made therein without departing from the scope of the invention as claimed. | A radiation detector assembly comprising a radiation detector (2), a readout device (3) coupled to the radiation detector (2) and platform means (4; 13) for supporting from a first major surface (13a) thereof the readout device (3) and the radiation detector (2), characterized in that the platform means (13) is comprised of aluminum nitride, and in that the first major surface (13a) comprises a patterned thin metallization film for coupling the readout device (3) to electrical terminals (6), and in that said metallization film has a first layer of titanium and at least a second layer of highly conductive material deposited thereon. The assembly of claim 1, characterized in that the platform means (13) further includes means integrally formed therewith for coupling to a cryogenic cooling apparatus (10). The assembly of claim 2, characterized in that the coupling means is comprised of an upstanding boss (14) that extends from a second major surface (13b) of the platform means (13), the boss (14) having a shape selected for coupling to the cryogenic cooling apparatus (10) and also being comprised of aluminum nitride. The assembly of claim 3, characterized in that the boss (14) is integrally formed and continuous with the second major surface (13b). The assembly of claim 4, characterized in that the platform (13) has a generally circular disk shape. The assembly of claim 5, characterized in that it has a diameter (D) of approximately 19,05 mm (0,75 inches) and a thickness (T) of approximately 0,508 mm (0,02 inches). The assembly of claim 5 or 6, characterized in that the boss (14) has a generally circular disk shape, and in that the diameter (Db) of the boss (14) is less than the diameter (D) of the platform (13). The assembly of claim 7, characterized in that it has a diameter (D) of approximately 19,05 mm (0,75 inches), and a thickness (T) of approximately 0,508 mm (0,02 inches), and in that the boss (14) has a diameter (Db) of approximately 8,89 mm (0,35 inches) and a thickness (H) of approximately 0,508 mm (0,02 inches). The assembly of any of the preceding claims, characterized by: coldshield means (8) coupled to the first major surface (13a) of the platform means (13) and extending outwardly therefrom for substantially enclosing the radiation detector (2) within an internal volume thereof; and housing means (11) including a window (12) positioned for passing externally generated radiation to an aperture within the coldshield means (8), the housing means (11) defining a vacuum enclosure within which the platform means (13) and coldshield means (8) are disposed. The assembly of claim 9, characterized in that the readout device (3) is comprised of silicon. The assembly of claim 9, characterized in that the platform means (13) and the upstanding coupling means (14) are actively brazed to a coldfinger tube (10) that is coupled to the cryogenic cooling apparatus. A method of fabricating a portion of a radiation detector dewar assembly (1; 20) comprising the steps of: providing a platform means (13) comprised of a dielectric material and having a first major planar surface (13a) for supporting a radiation detector means (2) thereon and an opposed second major planar surface (13b) having an upstanding portion (14) extending therefrom; characterized in that the platform means (13) is comprised of aluminum nitride; the upstanding portion is integrally formed and continuous with the second major surface (13b); the first major surface (13a) is patterned and thin film metallized with a first layer of titanium upon which at least a second layer of a highly conductive material is deposited; the platform means (13) is jointed to a first end of a conduit means (10) that is coupled during use at a second end thereof to a source of cryogenic cooling medium, the step of joining including a step of actively brazing the platform (13) to the first end of the conduit means (10). The method of claim 12, characterized in that the step of actively brazing includes the steps of: coating at least the upstanding portion (14) with an active brazing alloy; inserting the upstanding portion (14) into the first end of the conduit means (10); and heating the platform means (13) and the conduit means (10). The method of claim 13, characterized in that the step of heating occurs within a vacuum furnace. | SANTA BARBARA RES CENTER; SANTA BARBARA RESEARCH CENTER | MAASSEN NEVIL Q; PECK LEONARD E; ROMANO TIMOTHY S; MAASSEN, NEVIL Q.; PECK, LEONARD E.; ROMANO, TIMOTHY S. |
EP-0490170-B1 | 490,170 | EP | B1 | EN | 19,960,131 | 1,992 | 20,100,220 | new | G01T1 | null | H01J37, G01T1 | G01T 1/32 | Spin detector | A measured electron beam (2) having a polarization vector as represented by arrow (1) is irradiated to a ferromagnetic target (7) made of an iron single crystal through a polarization vector rotator (5) comprising a magnetic field generation coil (3) and an electrostatic lens (4). A magnetic field generator (8) is coupled with the target (7) and aligns the direction of magnetization of the target (7) in a direction represented by arrow (6). An oscillator (9) for providing a rotation signal of the polarization vector of the measured electron beam (2) is connected to the polarization vector rotator (5). The current absorbed by the target (7) is detected and amplified by a current amplifier (11). A lock-in amplifier (10) detects the phase and the magnitude of an A.C. component using the signal from the oscillator (9) as a reference signal. The magnitude of the D.C. component of the absorbed current is detected by a D.C. current detector (12). The ratio of the A.C. component of the absorbed current to its D.C. component is calculated by a division circuit (13). When the phase of this A.C. signal (ia) is detected by the lock-in amplifier (10) using the signal (saw tooth wave signal is) from the oscillator (9) as the reference signal, the phase difference Δ between the reference signal and the detected A.C. current corresponds to the angle defined between the polarization vector (arrow 1) of the measured electron beam (1) incident into the detector and the magnetization vector (arrow 6) of the target (7) and in this manner, the direction of the polarization vector can be detected. The magnitude of the polarization vector can be determined by dividing the amplitude (Ia) of the A.C. signal (ia) by the current (Id) detected by the D.C. current detector (12), by the division circuit (13). | BACKGROUND OF THE INVENTIONThis invention relates to measurement of a polarization vector of an electron beam and to a spin detector capable of detecting simultaneously the magnitude and direction of the polarization vector inside a two-dimensional plane or inside a three-dimensional space. A spin detector for detecting the direction and magnitude of a polarization vector by using absorption or scattering of a measured electron beam by a target is described, for example, in Electron Spin Polarization Ratio Detector (by Koike et al., JP-A-60-17846). According to this method, the trajectory of the measured electron beam incident along the center axis of the detector is once bent and spaced apart from the center axis, and is bent once again and is allowed to be incident into the target plane with a certain angle to the center axis, and is rotated around the center axis in such a manner that this angle of incidence and position of incidence do not change. SUMMARY OF THE INVENTIONHowever, it is by no means easy to rotate the electron trajectory without strictly changing the angle of incidence and the position of incidence, and since a gold evaporation film is used as the target, detection sensitivity is low. A component of the polarization vector can be detected with an incomparably higher sensitivity by use of a ferromagnetic substance as the target than by the use of the gold evaporation film, as described in Th. Dodt et al Europhysics Letter 6(4), 1988, 375. Use of a ferromagnetic target is also disclosed in App. Phys. Lett. 38 (7) 1 April 1981, p.p. 577-579. However, this method cannot detect simultaneously both the magnitude and direction of the polarization vector by one measurement. It is a primary object of the present invention to provide a spin detector which can detect simultaneously the magnitude and direction of the polarization vector with a high level of sensitivity without using any high level technique for adjusting the angle and position of the electro beam. This object is solved by the detector set forth in claim 1. An implementation of the present invention accomplishes high sensitivity detection by the use of a ferromagnetic substance as the target, allows the measured electron beam to be incident substantially vertically to the target surface so as to sufficiently minimize the dependence of the absorbed current on the angle of incidence, and rotates the polarization vector of the electron beam or the trajectory of the electron beam or the magnetization vector of the target around the center axis of the detector so as to accomplish a spin detector capable of detecting simultaneously the magnitude and direction of the polarization vector without requiring strict control. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 shows the fundamental structure of the first embodiment of the spin detector of the present invention; Fig. 2 is a waveform diagram useful for explaining a detection current in the embodiment shown in Fig. 1; Fig. 3 shows the fundamental structure of the second embodiment of the spin detector of the invention; Fig. 4 is a waveform diagram useful for explaining the detection current in the embodiment shown in Fig. 3; Fig. 5 shows the-fundamental structure of the third embodiment of the spin detector of the invention; Fig. 6 shows the fundamental structure of the fourth embodiment of the spin detector of the invention; Fig. 7 shows the fundamental structure of the fifth embodiment of the spin detector of the invention; Fig. 8 is a waveform diagram useful for explaining the detection current in the embodiment shown in Fig. 7; Fig. 9 shows the fundamental structure of the sixth embodiment of the invention; Fig. 10 is a waveform diagram useful for explaining the detection current in the embodiment shown in Fig. 9; Fig. 11 shows a modified embodiment of an electron beam detector that can be applied to the afore-mentioned embodiments; and Fig. 12 is a conceptual view showing an example of a cleaning method of the target surface of the spin detector of the invention. DESCRIPTION OF THE PREFERRED EMBODIMENTSThe D.C. current value of a current due to an electron beam absorbed by a ferromagnetic target or of a current due to an electron beam scattered by the target varies while it depends on the inner product of a polarization vector of an electron beam to be measured and a magnetization vector of the target. Accordingly, if the polarization vector of the trajectory or the magnetization vector is rotated and the change component of the current value of the electron beam absorbed by the target or of the current value of the electron beam scattered by the target or the change component of the current value which is obtained by synthesizing both of these electron beams in such a fashion that the phase of one of the current is opposite, is detected by a lock-in system by the use of the signals associated with the polarization vector or with the electron trajectory or with the rotation of the magnetization vector as the reference signal, so as to determine the magnitude and phase of the change component, then, the direction of the polarization vector can be determined from that phase and the magnitude of the polarization vector can likewise be determined from the ratio of its magnitude to the total absorbed currents or total scattered currents or the ratio of the total absorbed currents to the sum of the total scattered currents. Hereinafter, the structure of the spin detector of the present invention and the principle of its operation will be explained in detail with reference to the accompanying drawings. Fig. 1 shows the fundamental structure of the first embodiment of the spin detector of the present invention. In this embodiment, an electron beam 2 to be measured having a polarization vector represented by arrow 1 is irradiated to a ferromagnetic target 7 as an iron single crystal through a polarization vector rotator 5 comprising a magnetic field generation coil 3 and an electrostatic lens 4. The target 7 is coupled with a magnetic field generator 8 and the direction of this target 7 is aligned with the direction of arrow 6. An oscillator 9 for providing a rotation signal of the polarization vector of the electron beam 2 is connected to the polarization vector rotator 5. The current absorbed by the target 7 is detected and amplitude by a current amplifier 11. A lock-in amplifier 10 detects the phase signal and the magnitude of its A.C. components of absorbed current by the use of the signal from the oscillator 9 as a reference signal. The magnitude of the D.C. component of the absorbed current is detected by an ammeter 12. The ratio of the A.C. component of the absorbed current to the D.C. component is calculated by a division circuit 13. Here, the rotation of the polarization vector (represented by arrow 1) of the electron beam 2 to be measured is effected by a saw tooth wave current is of the oscillator 9 connected to the magnetic field generation coil 3 inside the polarization vector rotator 5, which current is changes to positive and negative polarities with a predetermined cycle and a predetermined amplitude. The polarization vector turns once per cycle of this current Is. This coil 3 has also the lens function. Therefore, focusing characteristics of the electron beam also change. For this reason, the focusing characteristics of the electron beam are kept constant by effecting a dynamic focusing adjustment for changing the intensity of the electrostatic lens in accordance with the field intensity (by changing the D.C. voltage Es to be applied to the electrostatic lens 4 in accordance with the current value is). Fig. 2 shows the relation between the saw tooth wave current is as the rotation signal from the oscillator 9 when the electron beam 2 to be measured is incident along the center axis of the polarization vector rotator 5 and the absorbed current ia of the target 7 which is detected and amplified by the current amplifier 11. When the saw tooth wave current is is caused to flow through the magnetic field generation coil 3 from the oscillator 9 and the polarization vector of the electron beam 2 is rotated at a uniform angular velocity around the center axis, the absorbed current ia by the target 7 changes sinusoidally as shown in Fig. 2. When the phase of this A.C. signal ia is detected by the lock-in amplifier 10 using the signal from the oscillator 9 (saw tooth wave current is) as the reference signal, the phase difference Δ between the reference signal and the detected A.C. signal corresponds to the angle described between the polarization vector (arrow 1) of the electron beam 2 incident into the detector and the magnetization vector (arrow 6) of the target 7 and in this way, the direction of the polarization vector can be detected. The magnitude of the polarization vector can be determined by dividing the amplitude Ia of the A.C. signal ia by the current Id detected by the D.C. current detector 12, by the use of the division circuit 13. Needless to say, the effective value or mean value of the A.C. signal ia can be used in place of the amplitude Ia of the A.C. signal ia and in this case, the magnitude of the polarization vector can be obtained by multiplying the resulting value by a suitable coefficient. This also holds true of later-appearing embodiments. Fig. 3 shows the fundamental structure of the second embodiment of the spin detector in accordance with the present invention. Whereas the embodiment shown in Fig. 1 detects the absorbed current of the target 7, this embodiment detects scattered electrons of the target 7 and the rest of constructions are the same as those of the embodiment shown in Fig. 1. The scattered electron 18 is detected by a scattered electron beam detector 17. In the embodiment shown in the drawing, the scattered electron 18 is detected by an MCP assembly (comprising a grid 16, a micro-channel plate 15 and an anode 14) for multiplying and detecting the beam and its output current is detected and amplified by an amplifier 11. When the electron beam 2 to be measured is irradiated onto the target 7 while the polarization vector of this beam 2 is rotated in the same way as in the first embodiment and the scattered electron 18 is detected, an output current having an A.C. signal ia, whose polarity is inverted to that of the first embodiment, can be obtained as shown in Fig. 4. The phase difference Δ and amplitude Ia of this A.C. signal are detected by a lock-in amplifier 10 in the same way as in the first embodiment and the current Id of the D.C. component is detected by a current detector 12. In this way, the magnitude and direction of the polarization vector can be detected. Though this spin detector becomes more expensive than the spin detector of the first embodiment, the polarization vector can be detected at a higher level of accuracy because a greater S/N can be obtained. Fig. 5 shows the fundamental structure of the third embodiment of the spin detector of the present invention. Whereas the target 7 in the embodiment shown in Fig. 1 is the iron single crystal, it is an amorphous iron alloy and the magnetization vector of the target 7 is rotated in place of the polarization vector of the electron beam to be measured in this embodiment. The rest of the constructions are the same as those of the embodiment shown in Fig. 1. A magnetic field generator 8 generates a rotating magnetic field in order to rotate the magnetization vector of the target 7. The signal is applied to the magnetic field generator 8 is substantially the same as the signal is applied to the polarization vector rotator 5, and is used for rotating the magnetization vector of the target 7 and also as the reference signal of the lock-in amplifier 10. The electron beam 2 to be measured is irradiated to the center axis of the target 7 and the magnetization vector (arrow 6) of the target 7 is rotated at a uniform angular velocity around this center axis by the signal from the oscillator 9. Then, the absorbed current ia by the target 7 changes sinusoidally in the same way as in Fig. 2. Though the current waveform of this absorbed current ia and its explanation are omitted, the phase signal and amplitude of this absorbed current ia are detected by the lock-in amplifier 10 in the same way as in the first embodiment. The magnitude and direction of the polarization vector can be detected by detecting the D.C. component by the current detector 12. Needless to say, a mechanical structure may be employed for rotating the magnetization vector by a ultrasonic motor, or the like, for example, in this embodiment. Since this embodiment does not require the dynamic focusing adjustment of the electron beam 2, the spin detector of this embodiment is easier to handle than those of the first and second embodiments. Fig. 6 shows the fundamental structure of the fourth embodiment of the spin detector of the present invention. This embodiment does not rotate both of the polarization vector of the measured electron beam 2 and the magnetization vector of the target 7. Instead, the electron beam 2 is rotated so that the trajectory of the electron beam 2 travels on the target 7 of the ring-like amorphous iron alloy which is shaped in a ring-like form and in which the magnetization vectors (arrow 6) are aligned in its circumferential direction. As a result, the polarization vector of the electron beam 2 to be measured is allowed to rotate relative to the magnetization vector of the target 7. This embodiment includes an electron trajectory rotator 21 for rotating the electron beam to be measured around its center axis. The signal Vs of the oscillator 9 applied to the electron trajectory rotator 21 is substantially the same as the signal is applied to the polarization vector rotator 5, rotates the electron beam 2 to be measured around the center axis and is also used as the reference signal of the lock-in amplifier 10. When the electron beam 2 to be measured is allowed to travel on the target 7 by the signal from the oscillator 9, the absorbed current ia by the target 7 changes sinusoidally in the same way as in Fig. 2. Though the current waveform of the absorbed current and its explanation are omitted, the phase signal and amplitude of this absorbed current are detected by the lock-in amplifier 10 in the same way as in the first embodiment and the D.C. component is detected by the current detector 12. In this way, the magnitude and direction of the polarization vector can be detected. This embodiment requires a target having high symmetry with respect to the axis. Since the rotating magnetic field need not be applied to the target, however, this embodiment can eliminate unnecessary bent of the trajectory of the incident electrons and scattered electrons due to the leakage magnetic field from the magnetic field generator 8. Fig. 7 shows the fundamental structure of the fifth embodiment of the spin detector of the present invention. In this embodiment, the electron beam 2 to be measured is alternately irradiated to the target having an inclination to its center axis and the magnetization vector of the target is set in a predetermined direction. To this and, an electron trajectory deflector 23 is disposed in place of the electron trajectory rotator 21 and this target 7 is constituted by a target group comprising four iron single crystal targets 7-1, 7-2, 7-3 and 7-4. Each target is connected electrically and is provided with an independent magnetic field generator 8 for providing a predetermined magnetization vector. Let's consider an orthogonal coordinates system comprising x, y and z axes, and set the center axis of the detector to the z axis. It will be assumed in this case that the four iron single crystal targets 7-1, 7-2, 7-3 and 7-4 of the target 7 have their magnetizations M₁, M₂, M₃ and M₄ expressed by the following formulas of disposition, respectively: M1 = M (cos 45°, 0, -sin 45°) M2 = M ( 0, -cos 45°, sin 45°) M3 = M (-cos 45°, 0, -sin 45°) M4 = M ( 0, cos 45°, sin 45°), ; where, M represents the magnitude of magnetization. First of all, the electron beam 2 to be measured is allowed to be incident and the electron trajectory is scanned so that the electron beam irradiation position reciprocates in a uniform cycle t₁ between the targets 7-1 and 7-3. Next, the electron trajectory is scanned so that the electron beam irradiation position reciprocates in a uniform cycle t₂ between the targets 7-2 and 7-4. Furthermore, these scanning operations are carried out alternately in a uniform cycle t₃. This scanning operation of the electron trajectory is carried out by applying a signal vs' from the oscillator 9 to a scanner 23. When such a scanning is carried out, the absorbed current ia by the target 7 changes periodically as shown in Fig. 8. The reason why the current reaches once zero is that the absorption of the electron beam does not exist when the electron beam shifts between the targets. The x component of the polarization vector can be detected by detecting the amplitude ia₁ of the absorbed currents ia obtained by the targets 7-1 and 7-3 among these targets and detecting the D.C. component Id₁ by the current detector 12. Similarly, the y component of the polarization vector can be detected by detecting the amplitude ia₂ of the A.C. signal of the absorbed current obtained from the targets 7-2 and 7-4 and detecting the D.C. component Id₂ by the D.C. current detector 12. Furthermore, as the mean value of the absorbed currents obtained by the targets 7-1 and 7-3 and the mean value of the absorbed currents obtained by the targets 7-2 and 7-4 change periodically, the z component of the polarization vector can be detected by calculating the amplitude ia₃ of the A.C. signal, the mean D.C. current Id₃ of the D.C. component Id₁ and of the D.C. component Id₂ from the amplitude ia₁, the amplitude ia₂, the D.C. component Id₁ and the D.C. component Id₂. Accordingly, if the detection of these three x, y and z components of the polarization vector and the calculation for arithmetically combining them are carried out by an operator 33, the direction and magnitude of the polarization vector in the coordinate axes x, y and z can be detected by arithmetic processing. In this embodiment, the timing signal from the oscillator 9 is used for stipulating the target, onto which the electron beam to be measured is irradiated, but not for the detection of the phase difference. In this embodiment, the trajectory of the electron beam 2 to be measured may be set to a round shape as shown in Fig. 6. In this case, the output of the current detector becomes different from the one shown in Fig. 8. But processing can be made in the same way as explained with reference to Fig. 8 because the signal from which target can be judged by referring to the signal from the oscillator 9. Whereas the first, second, third and fourth embodiments can simultaneously detect only two components of the polarization vector, this embodiment can simultaneously detect three components of the polarization vector. In the third, fourth and fifth embodiments, the polarization vector can be detected at a high level of accuracy by the method of detecting the scattered electrons from the target in the same way as in the second embodiment, though the method is not shown in the drawing as another embodiment. Fig. 9 shows still another embodiment of the present invention. This embodiment is structurally the same as the spin detector shown in Fig. 1. However, whereas the spin detector shown in Fig. 1 rotates the polarization vector of the electron beam at a uniform angular velocity, this embodiment rotates step-wise the polarization vector by 90°. The current ia absorbed by the target 7 at this time changes step-wise as shown in Fig. 10. When this current signal is detected by the lock-in amplifier 10 by the use of two reference wave signals sx and sy (see Fig. 10) the phases of which are different by 90° and which are obtained from the rotation signal is, signals Ax and Ay which are proportional to the two components Px and Py of the polarization vector can be obtained. When the formula Δ = tan⁻¹(Ax/Ay) is calculated by the operator 33 using the signals Ax and Ay, Δ proves to be the angle described between the polarization vector of the incident electron beam and the magnetization vector of the target. When Ax2 + Ay2 is divided by the current detector 12 by the divider 13, the magnitude of the polarization vector can be determined. When the magnetization vector of the target is step-wise rotated by 90° in the same way as in the third embodiment (shown in Fig. 5) in which the polarization vector is step-wise rotated by 90°, the direction and magnitude of the polarization vector can be likewise detected. This embodiment is particularly effective in the case where the axis of easy magnetization is symmetric four times as in the case of the (001) plane of the iron single crystal. Furthermore, high precision detection of the polarization vector can be made by detecting the absorbed current and scattered electrons of the target and synthesizing them in such a manner as to acquire a greater amplitude. An example of such a detector is shown in Fig. 11. This drawing diverts the structure of the detector disclosed in the afore-mentioned reference JP-A-60-178460 entitled Electron Spin Polarization Ratio Detector . The magnetization vector 6 is shown generated in the target 7 and the measured electron beam 2 is irradiated onto this target 7. A scattered electron beam detector 17 which is bored at the portion of its bottom corresponding to the target 7 and is bored at its upper part for the passage of the electron beam is disposed around the target 7. The absorbed current signal ia₄ obtained from the target 7 and the signal ia₅ obtained from the scattered electron detector 17 have the mutually inversed phases as such in Figs. 2 and 4. Therefore, an adder 35 adds them in opposite polarities and obtains a signal current ia₆. In the spin detector of the present invention, the target surface must be clean. Fig. 12 shows an example of this cleaning method with reference to the first and second embodiments. An ion beam 31 from an ion gun 30 sputters the target surface and at the same time, the target is heated by the radiant heat from a heating filament 32 disposed at the back of the target. In this way, a clean surface can be obtained. As is obvious from the explanation of the embodiments of the present invention given above, the position and angle of the electron beam may be controlled within the range which is permitted relatively widely with respect to the target. Therefore, the magnitude and direction of the polarization vector can be detected highly accurately and moreover, simultaneously, without using a high level of adjustment technique for making strict angle and position adjustment. Accordingly, the present invention provides extremely high scientific and industrial values. | A spin polarization detector utilizing dependence of a current of an electron beam (2) absorbed or scattered by a target (7) on a spin polarization state of the electron beam incident on the target, characterized in that said target is a ferromagnetic target, and by: rotation means (5, 8, 9, 21, 23) for rotating a polarization vector (1) of the electron beam incident on the target relative to a magnetization vector (6) of the target at the location of incidence, means (11, 12, 17) for detecting the AC and DC components of the absorbed and/or scattered electron beam current, means (10) for detecting the direction of said polarization vector (1) on the basis of the phase relationship between said AC component and the rotation effected by said rotation means, and means (13, 33) for detecting the magnitude of said polarization vector on the basis of said AC and DC components. A detector according to claim 1, further comprising: a polarization vector rotator (5) comprising a magnetic field generation coil (3) for rotating said polarization vector (1) of the incident electron beam (2) relative to said magnetization vector (6), and an electrostatic lens (4). A detector according to claim 2, wherein said polarization vector rotator (5) provides step-wise a rotation by 90°. A detector according to claim 1, further comprising: a magnetic field generator (8) for rotating said magnetization vector (6) relative to said polarization vector (1) of the electron beam (2). A detector according to claim 4, wherein said magnetic field generator (8) provides step-wise a rotation by 90°. A detector according to claim 1, wherein said ferromagnetic target (7) is a ring-like target uniformly magnetized in its circumferential direction, and said rotating means (9, 21) allows the electron beam to trace said target while said polarization vector (1) is kept in a predetermined direction. A detector according to claim 1, wherein said target comprises a plurality of segments (7-1, 7-2, 7-3, 7-4) having magnetization vectors in mutually different directions and so disposed as to possess a predetermined inclination with respect to the center axis of the electron beam incident thereto, and said rotating means (23) allow the electron beam to trace said segments while its polarisation vector (1) is kept in a predetermined direction. | HITACHI LTD; HITACHI, LTD. | FURUKAWA TAKASHI; KOIKE KAZUYUKI; MATSUYAMA HIDEO; FURUKAWA, TAKASHI; KOIKE, KAZUYUKI; MATSUYAMA, HIDEO |
EP-0490171-B1 | 490,171 | EP | B1 | EN | 20,000,614 | 1,992 | 20,100,220 | new | G02F1 | H04N9, G02B3 | G02B3, H04N9, G02F1, H04N5 | G02F 1/1335L, G02B 3/00A, H04N 5/74M4, S02F1:137K, H04N 9/31V | Scattering type liquid crystal device | A liquid crystal device for controlling scattering of light beams made incident upon a plurality of portions of a liquid crystal layer (4) thereof so as to modulate the light beams, the liquid crystal device including: a first lens array (2a) having lenses disposed to correspond to the portions of the liquid crystal layer, the lenses causing the light beams transmitted from the corresponding portions of the liquid crystal layer to travel toward a focal plane; a mask (6) for shielding scattered light transmitted from the first lens array and as well as allowing non-scattered light to pass through, the mask having a plurality of aperture portions which are formed along the focal plane to correspond to the lenses of the first lens array so as to allow non-scattered light transmitted from corresponding lenses to pass through; and a second lens array (3a) having lenses arranged to correspond to the aperture portions of the mask, the lenses substantially collimating the non-scattered light transmitted from corresponding aperture portions of the mask. | Field of the InventionThe present invention relates to a scattering type liquid crystal display apparatus according to the preamble of claim 1.A scattering type liquid crystal device has a liquid crystal layer which uses dynamic scattering mode liquid crystal (DSMLC), polymer droplet liquid crystal (PDLC) or polymer network liquid crystal (PNLC) to control scattering of light.Related Background Art A direct viewing type display apparatus according to the preamble of claim 1 using a device of the above-described type has been disclosed in Japanese Patent Publication No. 63-98631 and projection type display apparatuses each using a device of the above-described type have been respectively disclosed in Japanese Patent Laid-Open No. 50-99751 and U.S. Patent No. 4613207.The projection type display apparatus of this type has been arranged in such a manner that its projection optical system has a mask having apertures in order to shield scattered light from the liquid crystal device and to direct non-scattering light to the screen. However, there arises a problem in that a large quantity, which cannot be neglected, of scattered light passes through the apertures formed in the mask and it is made incident upon the screen, causing the quality of the image formed on the screen to be deteriorated.SUMMARY OF THE INVENTIONAccordingly, an object of the present invention is to provide an improved scattering type liquid crystal device. This object is achieved by a liquid crystal display apparatus comprising the features of claim 1. Further improvements are the subject of the dependent claims. Since the liquid crystal device according to the present invention is capable of shielding scattered light by a mask thereof at a position adjacent to the liquid crystal layer, scattered light travelling from the device toward the screen can be significantly reduced and thereby the quality of a formed image can be improved when it is applied to a projection type display apparatus. Other and further objects, features and advantages of the invention will be understood more fully from the following description. BRIEF DESCRIPTION OF THE DRAWINGSFig. 1 is a cross sectional view which illustrates an essential portion of the structure of an embodiment of a liquid crystal display device according to the present invention;Fig. 2 illustrates an optical principle when an enlarged projected image is formed by using the liquid crystal display device shown in Fig. 1;Fig. 3 is a plan view which illustrates the structure of the aperture mask shown in Fig. 1;Figs. 4 to 6 respectively illustrate the structures of first to third embodiments of a projection type display apparatus by using the liquid crystal display device shown in Figs. 1 and 2;Fig. 7 is a schematic structural view which illustrates a fourth embodiment of the projection type liquid crystal display apparatus according to the present invention;Figs. 8A and 8B are graphs which illustrate reflection characteristics of a reflecting film of a dichroic prism, where Fig. 8A is a graph which illustrates the reflection characteristics of a red reflecting film;Fig. 8B is a graph which illustrates the reflection characteristics of a blue reflecting film;Fig. 9 is a partial side elevational cross sectional view which illustrates the structure of a reflecting and scattering type liquid crystal device;Fig. 10 is a schematic structural view which illustrates a fifth embodiment of the projection type liquid crystal display apparatus according to the present invention;Fig. 11 is a schematic structural view which illustrates a sixth embodiment of the projection type liquid crystal display apparatus according to the present invention;Fig. 12 is a schematic structural view which illustrates a seventh embodiment of the projection type liquid crystal display apparatus according to the present invention;Fig. 13 is a schematic structural view which illustrates an eighth embodiment of the projection type liquid crystal display apparatus according to the present invention;Fig. 14 is a schematic structural view which illustrates a ninth embodiment of the projection type liquid crystal display apparatus according to the present invention;DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTSFig. 1 is a cross sectional view which illustrates an essential portion of an embodiment of the liquid crystal display device according to the present invention. Fig. 2 illustrates an optical principle of a function of forming an enlarged projected image by using the liquid crystal display device shown in Fig. 1. Fig. 3 is a plan view which illustrates the structure of an aperture mask 6 shown in Fig. 1.The liquid crystal display device shown in Fig. 1 comprises an active matrix scattering type liquid crystal plate 4, three glass plates 1 to 3 and an aperture mask 6.The scattering type liquid crystal plate 4 is disposed between the first transparent glass plate 1 and the second transparent glass plate 2, while the aperture mask 6 is disposed between the second glass plate 2 and the third transparent glass plate 3 so that an emission panel is constituted. The liquid crystal display device according to this embodiment is arranged in such a manner that the first glass plate 1 is made to be the light incidental side and the third glass plate 3 is made to be the light emission side. Furthermore, the portion of the second glass plate 2 adjacent to the scattering type liquid crystal plate 4 (light incidental side) and the portion of the third glass plate 3 adjacent to the light emission side are provided with first and second lens arrays 2a and 3a each of which is composed of a configuration of a plurality of lenses of a graded-index type which correspond to each pixel of the scattering type liquid crystal plate 4 in such a manner that the aperture mask 6 is made to be positioned at their focal points. Furthermore, the aperture mask 6 has a plurality of apertures, each of which, similarly to the first and the second lens arrays 2a and 3a, corresponds to a pixel of the scattering type liquid crystal plate 4 in such a manner that they form an array similary to the first and the second lens arrays 2a and 3a. As a result, it constitutes a schlieren optical system in cooperation with the first lens array 2a. The thicknesses of each of the second and the third glass plates 2 and 3 are made to be the same as the focal distances of each of the lens arrays 2a and 3a. Therefore, incident light beam 7, which has passed through the transmission mode pixels of the scattering type liquid crystal plate 4 is, as designated by a continuous line shown in Fig. 1, caused to travel while being focused at the aperture portion of the aperture mask 6 by the corresponding lens of the first lens array 2a. Then, it is made to be an emitted light beam 8, which is a parallel beam, by the corresponding lens of the second lens array 3a before it is emitted outwards.In a case where it has passed through the scattering mode pixels of the scattering type liquid crystal plate 4, the incident light beam 7 is diffused as designated by a dashed line of Fig. 1 and thereby the major portion of it is shielded by the aperture mask 6. Therefore, the outward leakage of light is prevented.A liquid crystal display device 9 shown in Fig. 2 is structured as shown in Fig. 1. A light beam generated by a light source 11 is made to be a parallel light beam 7 (incident light beam) by a parabolic mirror 10 before it passes through the liquid crystal display device 9 which is a light valve. As a result, it is made to be the emitted light beam 8 which is a parallel image light beam, causing the light incident side to be projected to a screen 14 by a projection lens 13 of telecentric system which is formed on the light incident side while being enlarged.The aperture mask 6 has aperture mask apertures (apertures) 16 which correspond to the pixels of the scattering type liquid crystal plate 4, the aperture mask apertures being disposed to form a lattice as shown in Fig. 3. The material and the color of the aperture mask 6 are not limited particularly. However, it is preferable that black be employed because it exhibits excellent light absorption. The optimum aperture area of the aperture mask apertures 16 and the thickness of each of the glass plates 2 and 3 are determined in accordance with the power (the focal distance) of each of the lens arrays 2a and 3a, the parallelism of the incidental light beam 7, the scattering characteristics of the scattering type liquid crystal plate 4 and the size of each pixel.As described above, the liquid crystal device 9 according to this embodiment is arranged in such a manner that the schlieren optical system is formed for each pixel. Therefore, a projection type display apparatus constituted by using the above-described device 9 exhibits excellent performance of removing scattered light in comparison to a conventional device in which a single schlieren optical system is formed for one frame. Therefore, generation of flare and ghost can be prevented satisfactorily.Also in a case where the above-described structure is constituted, the introduction of the portion of the leakage into the adjacent image cannot exceed a level which causes the contrast to be lowered or causes the flare to be generated. Assuming that the parallelism of light emitted from an ordinary light source is ± 5 degrees and as well as the schlieren optical system comprising lens array 2a and an aperature mask 6 is designed to be formed into an optimum structure, the contrast of the liquid crystal display device according to this embodiment is 100:1 or more and the worst value of the adjoining interference is 1/200 or less.Fig. 4 is a structural view which illustrates a projection type display apparatus constituted by using the liquid crystal display device shown in Fig. 2.According to this embodiment, a red image light beam of the light beams generated in the light source 11 illuminates the liquid crystal display device 9R via a red reflecting dichroic mirror 20 and a reflecting mirror 19. A green image light beam and a blue image light beam respectively illuminate liquid crystal display devices 9G and 9B via a red reflecting dichroic mirror 20 and a green reflecting dichroic mirror 21.Each of the color image light beams obtained by illuminating the liquid crystal display devices 9R, 9G and 9B are synthesized by a reflecting mirror 22, a green reflecting and red permeable dichroic mirror 23 and a blue reflecting dichroic mirror 24 before the synthesized light beam is made incident upon a lens 18. The above-described lens 18 constitutes the schlieren optical system in cooperation with an aperture stop 17. Thus, the synthesized illuminating light beam from which scattered light has been further removed is projected on the surface of the screen 14 in an enlarged manner by a projection lens 13 disposed next to the aperture stop 17. According to this embodiment, the projection optical system (13, 17 and 18) is formed into a system the light incident side of which is formed into a telecentric structure.According to this embodiment, the liquid crystal devices 9R, 9G and 9B each including the micro-schlieren optical system and the schlieren optical system composed of the lens 18 and the aperture stop 17 are combined to each other. Therefore, generation of scattered light is further prevented and also the interference (adjoining interference) in the liquid crystal display device can be prevented. As a result, the employed optical devices can be further freely disposed or the dimensions can be determined also freely, causing an effect to be obtained in that the overall size of the apparatus can be reduced.Fig. 5 illustrates the structure of a second embodiment of the projection type display apparatus which employs the liquid crystal display device shown in Figs. 1 and 2.According to this embodiment, a projection type display apparatus is formed into a 3-lens 3-liquid crystal apparatus. A light beam generated in the light source 11 is made to be a parallel beam by the parabolic mirror 10 disposed in the rear of the light source 11. The parallel beam thus-formed is made incident upon the red reflecting dichroic mirror 20 and a blue reflecting dichroic mirror 26 disposed to intersect each other so that it is decomposed into red, blue and green light beams. Each of the red light beam and the blue light beam is returned by the reflecting mirrors 19 and 22 so as to respectively illuminate the liquid crystal display devices 9R and 9B. On the other hand, the green light beam passes through each of the above-described dichroic mirrors 20 and 26 so as to illuminate the liquid crystal device 9G.The color image light beams obtained from each of the liquid crystal display devices 9R, 9G and 9B are respectively made incident upon the lenses 18R, 18G and 18B. The above-described lenses 18R, 18G and 18B constitute a schlieren optical system in cooperation with an aperture stop 17A. As a result, scattered light is removed from each of the image light beams which is, in an enlarged view, then projected on the surface of the transmission type screen 14 by projection lenses 13R, 13G and 13B.Fig. 6 illustrates the structure of a third embodiment of the projection type display apparatus constituted by using the liquid crystal display device according to the present invention.According to this embodiment, the liquid crystal display device including the micro-schlieren optical system shown in Fig. 1 is applied to an ordinary optical system which uses a TN type liquid crystal device.Since the structure of the optical system according to this embodiment is arranged similarly to the embodiment shown in Fig. 4 except for the omission of the lens 18 and the aperture stop 17, the same reference numerals are given to the same elements and therefore their descriptions are omitted here.Since the liquid crystal display devices 9R, 9G and 9B are individually able to prevent generation of scattered light, the contrast obtainable from the TN type liquid crystal display device can be obtained. Furthermore, since no polarizing plate is used, an advantage can be obtained in that brightness can be doubled even if the same light source is used.Although the liquid crystal display device is arranged to be the active matrix type display device according to the above-described embodiments, a simple matrix type display device may be employed. Furthermore, the structure arranged in such a manner that the graded-index lens disposed in the liquid crystal display device is positioned to correspond to each pixel may be replaced by a structure in which the same is positioned to correspond to a plurality of pixels.Since the liquid crystal display device is arranged in such a manner that the schlieren effect can be generated in each pixel, generation of scattered light in the liquid crystal display device can be reduced. Furthermore, the aperture mask is disposed to confront each pixel so that undesirable light incidence from other liquid crystal display devices and undesirable introduction of leaked light to the adjacent pixels can be reduced or prevented.Since the above-described light shielding function is given to the device level, an image from which flare or ghost has been removed and which thereby exhibits excellent contrast can be obtained in a case where the projection type display apparatus is constituted by using the liquid crystal display device according to the present invention. Furthermore, since the light shielding mechanism can be reduced from the overall structure of the apparatus, the overall size of the apparatus can be reduced.Furthermore, it can be used in place of the TN type liquid crystal. In this case, since the polarizing plate for use with the TN type liquid crystal is not used, the brightness can be doubled and therefore the light source can efficiently be used.Fig. 7 is a schematic structural view which illustrates a fourth embodiment of the projection type liquid crystal display apparatus according to the present invention.The projection type liquid crystal display apparatus according to this embodiment comprises a light source portion having a light source 11, a parabolic mirror 12 and a lens 33. Furthermore, the liquid crystal display apparatus comprises a dichroic prism 34 in which a red reflecting dichroic film 34R and a blue reflecting dichroic film 34B are intersected to each other. The liquid crystal display apparatus further comprises a red reflecting and scattering type liquid crystal device 35R, a green reflecting and scattering type liquid crystal device 35G and a blue reflecting and scattering type liquid crystal device 35B which are respectively disposed on the three sides of the dichroic prism 34. In addition, the liquid crystal display apparatus further comprises a convergent lens 36 disposed between the dichroic prism 34 and the screen 14. Furthermore, the liquid crystal display apparatus further comprises a first shielding mask 37 disposed adjacent to the convergent point (focal point) of the convergent lens 36 on either side of the convergent point (according to this embodiment, on the illustrated side) to run parallel to the screen 14. In addition, the liquid crystal display apparatus further comprises a reflecting mirror 38 an end portion of which is placed to confront an end portion of the above-described convergent point of the first mask 37 while making a predetermined angle from the same, the reflecting mirror 38 being arranged to reflect light emitted from the above-described light source portion to make it incident upon the convergent lens 36. Furthermore, the liquid crystal display apparatus further comprises a second shielding mask 39 disposed on the same plane as the mirror surface of the reflecting mirror 38, an end portion of the shielding mask 39 being positioned in contact with another end portion of the reflecting mirror 38.The red reflecting and scattering type liquid crystal device 35R is disposed on the side surface of the dichroic prism 34 which confronts the reflecting surface of the red reflecting film 34R. The blue reflecting and scattering type liquid crystal device 35B is disposed on the side surface of the dichroic prism 34 which confronts the reflecting surface of the blue reflecting film 34B. The green reflecting and scattering type liquid crystal device 35G is disposed on the side surface which confronts the incident and emission side of the dichroic prism 34.As shown in Fig. 8A, the red reflecting film 34R of the dichroic prism 34 has reflecting characteristics with which only light (red light beam), the wavelength λ of which is 600 nm or more, is reflected. As shown in Fig. 8B, the blue reflecting film 34B of the dichroic prism 34 has reflecting characteristics with which only light (blue light beam), the wavelength λ of which is 500 nm or less, is refelected. Therefore, the above-described red reflecting and scattering type liquid crystal device 35R receives only the red light beam of white light beam emitted from the above-described light source portion, while the blue reflecting and scattering type liquid crystal device 35B receives only the blue light beam of the above-described white light beam. Furthermore, the green reflecting and scattering type liquid crystal device 35G received only the green light beam of the above-described white light beam.Fig. 9 is a partial side elevational cross sectional view which illustrates the structure of the reflecting and scattering type liquid crystal devices 35R, 35G and 35B.Each of the reflecting and scattering type liquid crystal devices 35R, 35G and 35B is structured in which a first glass layer 120, a reflecting mirror layer 121, a scattering type liquid crystal plate 122, a second glass layer 124 and a third glass layer 126 are sequentially stacked in this order, the reflecting and scattering type liquid crystal device being a modification made in such a manner that the device shown in Fig. 1 is made to be a reflecting type device. The liquid crystal of the scattering type liquid crystal 122 is polymer droplet liquid crystal (PPLC) or polymer network liquid crystal (PNLC). The liquid crystal of this type can be applied to the device shown in Fig. 1. The surface of the second glass 124, which is allowed to adhere to the scattering type liquid crystal layer 122, has a first graded-index lens array 123 formed to correspond to each pixel. The incident surface of the third glass layer 126 has a second graded-index lens array 127 formed to confront the first graded-index lens 23. Furthermore, the surface of adhesion to be made between the second glass layer 124 and the third glass layer 126 has an aperture mask 125 for absorbing light. The aperture mask 125 has apertures 125 formed in such a manner that each of the apertures 125 confronts the center of the lens of each of the above-described two graded-index lens arrays 123 and 127. That is, when the reflecting and scattering type liquid crystal device 35 is viewed from the incident surface of the third glass layer 126, the aperture 25a of the aperture mask 125 is positioned at the central position of each pixel as shown in Fig. 3.Therefore, as designated by a continuous line of Fig. 9, the parallel light beam made incident upon the light incident surface of the third glass layer 126 and to be applied to one pixel of the scattering type liquid crystal plate 122 is converged by the lens of the second graded-index lens array 127. Then, the light beam passes through the aperture 125a of the aperture mask 125 before it is again made to be a parallel beam by the lens of the first graded-index lens array 123 so as to be made incident upon the scattering type liquid crystal plate 122.The aperture mask 125 acts in such a manner that it causes the modulated parallel beam to be emitted from the device when the scattering type liquid crystal plate 122 is in a transmission mode and it inhibits the light emission from the device when the scattering type liquid crystal plate 22 is in a scattering mode. The aperture mask 125 constitutes a schlieren optical system in cooperation with the above-described two graded-index lens arrays 123 and 127.That is, when the scattering type liquid crystal plate 122 is in the transmission mode, the parallel beam made incident upon the scattering type liquid crystal plate 122 is reflected by the reflecting mirror 121. Then, it is, as a parallel beam, emitted from the scattering type liquid crystal plate 122 before it is converged at the focal point by the lens of the first graded-index lens array 123. Then, the converged light beam passes through the aperture 125a of the aperture mask 125 before it is returned to a parallel beam by the lens of the second graded-index lens array 127. Then, the parallel beam is emitted from the incident surface of the third glass layer 126. In a case where the scattering type liquid crystal plate 122 is in the scattering mode, the above-described parallel beam reflected by the reflecting mirror 121 is made to be scattered light because it is not converged as designated by a dashed line of Fig. 9 even if it passes through the lens of the first graded-index lens array 123 but it is scattered. Therefore, scattered light is substantially absorbed by the aperture mask 25 and thereby it is stopped.The operation of the above-described projection type liquid crystal display apparatus will now be described with reference to Fig. 7.The white light beam emitted from the light source portion composed of the light source 11, the parabolic mirror 12 and the lens 33 is made incident upon the reflecting mirror 38 so that it is reflected to the convergent lens 36. The reflected white light beam is substantially converted into a parallel beam by the convergent lens 36 before it is made incident upon the cross dichroic prism 34.A red light beam of the above-described white light beam made incident upon the cross dichroic prism 34 is reflected by the red reflecting film 34R before it is made incident upon the red reflecting and scattering type liquid crystal device 35R in which it is then modulated in accordance with the red color component of the image. A blue light beam is reflected by the blue reflecting film 34B before it is made incident upon the blue reflecting and scattering type liquid crystal device 35B in which it is modulated in accordance with the blue color component of the image. A green light beam passes through the red reflecting film 34R and the blue reflecting film 34B before it is made incident upon the green reflecting and scattering type liquid crystal device 35G in which it is modulated in accordance with the green component of the image.The red image light beam, the blue image light beam and the green image light beam modulated by the above-described three reflecting and scattering type liquid crystal devices 35R, 35B and 35G are emitted from the devices since they are reflected by the reflecting mirror layer 121 (sea Fig. 9). As a result, the red image light beam is reflected by the red reflecting film 34R toward the screen 14. The modulated blue light beam is reflected by the blue reflecting film 34B toward the screen 14. The modulated green light beam passes through the red reflecting film 34R and the blue reflecting film 34B. As a result, the color light beams are respectively synthesized before it is emitted from the cross dichroic prism 34 as a substantially parallel light beam.The above-described parallel light beam is converged at a portion adjacent to the aperture portion formed by an end portion of the first shielding mask 37 and an end portion of the reflecting mirror 38 by the convergent lens 36. The light beam, which has passed through the above-described aperture portion, is projected to the screen 14 via a projection lens 30. As a result, the above-described image is projected onto the screen 14 in an enlarged manner. According to this embodiment, the optical system composed of the lenses 30, 36, members 37, 38 and 39 is arranged in such a manner that the light incidental side is a telecentric structure.In this case, the above-described three reflecting and scattering type liquid crystal devices 35R, 35B and 35G are brought into the scattering mode depending upon the above-described image, causing slight quantity of scattered light, which is unnecessary light, to be emitted from the cross dichroic prism 34. However, a portion of scattered light is absorbed and thereby shielded by the first shielding mask 37 and the second shielding mask 39 or the same is reflected by the reflecting mirror 38 to be returned to the above-described light source portion. Therefore, it cannot substantially be projected onto the screen 14. As a result, in the projection type liquid crystal display device according to this embodiment, the devices 35R, 35G and 35B serve as the masks so that generation of the flare or the ghost in the image projected onto the screen 14 in an enlarged manner due to the above-described scattered light can be reduced.Furthermore, since the schlieren optical system is composed of the convergent lens 36, the first shielding mask 37 and the reflecting mirror 38, the contrast of the image projected onto screen 14 in an enlarged manner can be raised.Fig. 10 is a schematic structural view which illustrates a fifth embodiment of the projection type liquid crystal display apparatus according to the present invention.The projection type liquid crystal display apparatus according to this embodiment is different from the projection type liquid crystal display apparatus shown in Fig. 7 in that aqueous solution of ethylene glycol 42 is enclosed between the three reflecting and scattering type liquid crystal devices 35R, 35B and 35G and the cross dichroic prism 34 so that each of the three reflecting and scattering type liquid crystal devices 35R, 35B and 35G and the cross dichroic prism 34 are optically coupled.In a case where the brightness of the projection type liquid crystal display apparatus is raised, each aperture mask 125 (see Fig. 9) absorbs scattered light emitted from each scattering type liquid crystal plate 122 if a black (dark) image is continued for a long time, causing the temperature of the above-described three reflecting and scattering type liquid crystal devices 35R, 35B and 35G to be raised. If the temperature is raised excessively, the operation of the scattering type liquid crystal plate 122 becomes unstable or stopped.Accordingly, the projection type liquid crystal display apparatus according to this embodiment is arranged in such a manner that the aqueous solution of ethylene glycol 42 is enclosed between the three reflecting and scattering type liquid crystal devices 35R, 35B and 35G and the cross dichroic prism 34. As a result, the three reflecting and scattering type liquid crystal devices 35R, 35B and 35G are cooled to prevent the temperature rise for the purpose of stabilizing the operation of the scattering type liquid crystal plate 122 and raising the brightness.Furthermore, since the aqueous solution of ethylene glycol 42 the refraction factor of which is about 1.5 is used, reflection of light taken place between the above-described three reflecting and scattering type liquid crystal devices 35R, 35B and 35G and the cross dichroic prism 34 can be prevented. Therefore, the deterioration in the image quality can be prevented.Although the aqueous solution of ethylene glycol 42 is employed to optically couple the three reflecting and scattering type liquid crystal devices 35R, 35B and 35G and the cross dichroic prism 34, silicone oil the refraction factor of which is about 1.5 may be used.Fig. 11 is a schematic structural view which illustrates a sixth embodiment of the projection type liquid crystal display apparatus according to the present invention.The projection type liquid crystal display apparatus according to this embodiment is different from the projection type liquid crystal display apparatus shown in Fig. 7 in that the synthesized image light beam emitted from the convergent lens 36 does not pass through the projection lens when it is projected onto the screen 14.Therefore, since the number of the lens elements in the optical system can be reduced in the projection type liquid crystal display apparatus according to this embodiment, the overall size of the apparatus can be reduced in comparison to that shown in Fig. 7.The projection type liquid crystal display apparatus shown in Fig. 11 is structured into a known front projection type apparatus in which the liquid crystal device is disposed adjacent to the user. In a case where a known backside projection type structure in which the liquid crystal device is included in the body of the apparatus is employed, an advantage can be obtained in that the cost can be reduced.Fig. 12 is a schematic structural view which illustrates a seventh embodiment of the projection type liquid crystal display apparatus according to the present invention.The projection type liquid crystal display apparatus according to this embodiment is different from the projection type liquid crystal display apparatus shown in Fig. 7 in that a fresnel lens 36A is used in place of the convergent lens 36 to convert the white light beam emitted from the light source portion and reflected by the reflecting mirror 38 into a substantially parallel light beam before it is made incident upon the cross dichroic prism 34. Furthermore, the synthesized image light beam emitted from the cross dichroic prism 34 is converged at an aperture portion formed by an end portion of the first shielding mask 37 and an end portion of the reflecting mirror 38.Since the fresnel lens 36A can be disposed to correspond to a position which substantially comes in contact with the cross dichroic prism 34 in the projection type liquid crystal display apparatus as compared with the use of ordinary convex lens as convergent lens 36, the overall size of the apparatus can be reduced.Fig. 13 is a schematic structural view which illustrates an eighth embodiment of the projection type liquid crystal display apparatus according to the present invention.The projection type liquid crystal display apparatus according to this embodiment is different from the projection type liquid crystal display apparatus shown in Fig. 12 in the following structures: (A) The aqueous solution of ethylene glycol 42 the refraction factor of which is about 1.5 is enclosed between the three reflecting and scattering type liquid crystal devices 35R, 35B and 35G and the cross dichroic prism 34 so that each of the three reflecting and scattering type liquid crystal devices 35R, 35B and 35G and the cross dichroic prism 34 are optically coupled.(B) The aqueous solution of ethylene glycol 42 the refraction factor of which is about 1.5 is also enclosed between the fresnel lens 36B and the cross dichroic prism 34 so that the fresnel lens 36B and the cross dichroic prism 34 are optically coupled.(C) The fresnel lens 36B is disposed in such a manner that its lens confronts the screen 14.According to the projection type liquid crystal display apparatus, similarly to that shown in Fig. 10, the aqueous solution of ethylene glycol 34 is used to prevent the temperature rise of each of the scattering type liquid crystal plate 122 (see Fig. 9) of the above-described three reflecting and scattering type liquid crystal devices 35R, 35B and 35G. Therefore, the brightness can be raised. Furthermore, in a case where the fresnel lens 36B is made of plastic in order to reduce the cost, the problem of the unstable light convergent operation of the fresnel lens 36B can be prevented, the unstable light convergent operation being due to the deformation of the plastic fresnel lens 36B by the heat of the white light beam emitted from the light source portion and the heat of the modulated white light beam emitted from the dichroic prism 34.Furthermore, the white light beam emitted from the light source portion and reflected by the reflecting mirror 38 is, as shown in Fig. 13, made incident upon the fresnel lens 36B while making a predetermined angle from it. Therefore, it is preferable that the above-described lens side of the fresnel lens 36B confronts the cross dichroic prism 34 (the flat side confronts the screen 14) in order to prevent the eclipse of the white light beam at the lens side of the fresnel lens 36B. However, no problem takes place even if the lens side is made to confront the screen 14 according to this embodiment since the degree of the influence of the eclipse is small.Also according to this embodiment, silicone oil the refraction factor of which is about 1.5 may be used in place of the aqueous solution of ethylene glycol 34.Fig. 14 is a schematic structural view which illustrates a ninth embodiment of the projection type liquid crystal display apparatus according to the present invention.The projection type liquid crystal display apparatus according to this embodiment is different from that shown in Fig. 12 in that two fresnel lenses 36C and 36D are used to convert the white light beam emitted from the light source portion and reflected by the reflecting mirror 38 into a substantially parallel beam before it is made incident upon the cross dichroic prism 34. Furthermore, the modulated white light beam emitted from the cross dichroic prism 34 is converged at the aperture portion formed by an end portion of the first shielding mask 37 and an end portion of the reflecting mirror 38.In the projection type liquid crystal apparatus according to this embodiment, the above-described white light beam made incident from the reflecting mirror 38 while making a predetermined angle is converted into a substantially parallel beam by using the two fresnel lenses 36C and 36D. As a result, each of the lens side of fresnel lenses 1261 and 1262 can easily be designed. The present invention can preferably be applied to any of the known scattering type liquid crystal display devices capable of controlling scattering and transmission of light for each pixel exemplified in the description of the related background art. Furthermore, the simple matrix system and the active matrix system have been known as the method of driving the liquid crystal medium. | A liquid crystal display apparatus comprising a scattering type liquid crystal device (9) comprising a liquid crystal layer (4) for controlling scattering or non-scattering of light beams (7) made incident upon a plurality of pixel portions of said liquid crystal layer (4), said scattering type liquid crystal device having two substrates (1; 2) sandwiching said liquid crystal layer (4),a first lens array (2a) having a plurality of lenses disposed to correspond to each respective pixel portion of said liquid crystal layer (4) causing said light beams to travel from said corresponding portions of said liquid crystal layer (4) toward a focal plane, anda mask (6) for shielding scattered light and for allowing non-scattered light to pass through,said mask (6) being arranged on the focal plane, and comprising a plurality of aperture portions which are formed along said focal plane so that each aperture portion corresponds to a respective pixel portion of said liquid crystal layer (4) as well as to a respective lens of said first lens array (2a) so as to allow each respective non-scattered light beam to be transmitted from each corresponding lens to pass through said corresponding aperture and to shield each respective scattered light beam transmitted from said first lens array,characterized in thatsaid liquid crystal display apparatus is a projection type display apparatus which further comprisesan optical projecting system, anda second lens array (3a) having a plurality of lenses arranged to correspond to said respective aperture portions of said mask (6), said lenses substantially collimating each non-scattered light beam transmitted from said corresponding aperture portion of said mask (6) and directing it to said projecting optical system,the apparatus being further characterized in that said first lens array (2a) comprises a graded index lens array formed in the substrate (2) which is on the projection side of said liquid crystal layer (4), the lens array (2a) being formed adjacent the surface of said substrate (2) which faces said liquid crystal layer (4).A liquid crystal display apparatus according to Claim 1, wherein each lens of said second lens array (3a) comprises a graded-index lens.A liquid crystal display apparatus according to Claim 1, wherein a first and a second transparent plate (2, 3) are stacked to each other while holding said mask (6) therebetween, said first lens array (2a) is formed on said first transparent plate (2) and said second lens array (3a) is formed on said second transparent plate (3).A liquid crystal display apparatus according to Claim 1 or 3, wherein said light beam is caused to travel toward said liquid crystal layer (4) via said mask (6) and said first lens array (2a) and a reflecting surface for reflecting and returning said light beam, which has passed through said liquid crystal layer (4), to said liquid crystal layer (4) is disposed at a position opposing said first lens array (2a). A projector in which an image formed by an illuminated liquid crystal light valve is projected by an optical system, wherein said projector comprises a liquid crystal display apparatus according to Claim 1.A projector according to Claim 5, wherein said light valve comprises a reflecting type light valve which is illuminated by said light from said optical system side.A projector according to Claim 5, wherein said light valve comprises a transmissive type light valve which is illuminated by said light from a side opposing said optical system.A projector according to Claim 5, wherein said light valve is illuminated by light which has been substantially collimated. | CANON KK; CANON KABUSHIKI KAISHA | KUREMATSU KATSUMI; MINOURA NOBUO; MITSUTAKE HIDEAKI; SUZUKI HIDETOSHI; YOSHINAGA KAZUO; KUREMATSU, KATSUMI; MINOURA, NOBUO; MITSUTAKE, HIDEAKI; SUZUKI, HIDETOSHI; YOSHINAGA, KAZUO; KUREMATSU, KATSUMI, C/O CANON KABUSHIKI KAISHA; MINOURA, NOBUO, C/O CANON KABUSHIKI KAISHA; MITSUTAKE, HIDEAKI, C/O CANON KABUSHIKI KAISHA; SUZUKI, HIDETOSHI, C/O CANON KABUSHIKI KAISHA; YOSHINAGA, KAZUO, C/O CANON KABUSHIKI KAISHA |
EP-0490173-B1 | 490,173 | EP | B1 | EN | 19,970,409 | 1,992 | 20,100,220 | new | H02K15 | H02K15 | H02K15 | T02K15:00E, H02K 15/095 | Stator winding machine | Methods and apparatus for winding the stator of an electric motor with two wires simultaneously are provided. The apparatus includes a stator winding needle having two separate wire delivery channels. The leads of the two wire to be wound are passed through the winding needle and are held by start lead holders. When winding is complete, the wires are identified by a lead pulling apparatus which rotates in a predetermined direction to grip an appropriate wire. The lead pulling apparatus draws each of the wires to a termination lead holder. Each wire is gripped and cut by a gripping assembly, which holds the cut leads in a predetermined position to facilitate winding of a subsequent stator. | Background of the InventionThis invention relates to a machine for winding coils of wire onto a stator of an electric motor. More particularly, this invention relates to a winding machine which winds a stator pole with two wires simultaneously. It is often desirable to wind a stator pole with two wires. For example, two stator wires may be required to provide a means for controlling the speed of the armature of a motor during motor operation. However, if the stator wires are wound sequentially, production times are increased. Thus, it is desirable to wind the stator with two wires simultaneously. However, simultaneously winding the stator with two wires poses several technical problems. If two wires are wound simultaneously, one wire may be pinched between the winding needle and the second wire, resulting in damage to the wire or insulation. This is particularly true if the wires are of different diameters. Also, the two wires may become twisted. Once the wires are wound, the leads of the appropriate wires must be identified for making the proper terminal connections. It is desirable to place the identified leads in a known position, to facilitate further automated processing of the stator. US-A-3383058 discloses the simultaneous winding of two wires on the pole of a stator by using a needle having distinct delivery channels for passage of the wire. The needle becomes separated in two distinct parts in order to secure the coil leads to the stator. High speed winding of a stator pole as is required in modern stator manufacturing would be impeded by these technical principles. Summary of the InventionIt is an object of this invention to provide a stator winding machine which winds simultaneously two wire coils onto a stator pole of an electric motor, without damaging the wires or insulation. It is also an object of this invention to provide a stator winding machine which identifies the respective leads of the two coils. It is another object of this invention to provide a stator winding machine which places the leads of the wound coils in a known position, to facilitate further automated processing of the stator. It is a further object of this invention to provide a stator winding machine which temporarily anchors the start and finish leads of a stator wound with two wires simultaneously. A still further object of this invention is to provide a stator winding machine which forms an intermediate, continuous lead for the stator coils, and attaches the continuous lead to a terminal seat of the stator. In accordance with this invention, there is provided a stator winding apparatus according to claim 1 and method according to claim 11 in which two wires are wound simultaneously onto a stator pole. The winding machine includes a winding needle which has two separate wire delivery channels. The separate delivery channels ensure that the wires and insulation are not damaged during winding. The wires exit the channels in distinct directions to facilitate processing by gripper and lead pulling assemblies. An unwound stator is mounted in a housing having holders for gripping the start and finish leads of a wound stator. A gripping assembly delivers the start leads of the wires exiting the needle to the start lead holders, which hold the leads in predetermined positions. The needle then winds the stator pole with the two wires. When winding is complete, a lead pulling assembly grips a wire by rotating in a predetermined direction, and draws the wire past a finish lead holder. The finish lead holder secures the lead. The gripping assembly then grips the wire at a point beyond the finish lead holder, and cuts the wire. The lead pulling assembly grips the second wire by rotating in a second predetermined direction, and draws the second wire past a second finish lead holder. The gripping assembly then grips and cuts the second wire. The wound stator, still mounted on the housing, may then be removed from the winding machine. The stator may be transferred to another apparatus for further processing. The gripper assembly is left holding, in a known position, the start leads of the next stator to be wound. Brief Description of the DrawingsThe above objects and advantages of the invention will be apparent upon consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which like reference numbers refer to like parts throughout, and in which: FIG. 1 is a partial, elevational view of a stator winding machine constructed in accordance with the principles of the present invention, showing the top of a wound stator; FIG. 2 is a side view of the machine of FIG. 1, taken along lines 2-2; FIG. 3 is a top view of the machine of FIG. 2, taken along lines 3-3; FIG. 4 is an elevational view of the machine of FIG. 3, taken along lines 4-4; and FIG. 5 is a partial elevational view of the stator of FIG. 1. Detailed Description of the InventionReferring now to the drawings, the stator winding machine of the present invention winds a pole of a stator 10 with coils of wire 12. Stator 10 having a longitudinal axis (x) typically is mounted in a housing 14, which may remain attached to the stator after winding. The stator winding machine typically may include a winding needle 16, a lead-pulling assembly 18, and a gripping assembly 20 (shown in FIG. 2, the position of which is shown in FIG. 1 in phantom, indicated by reference number 21). Each wire is fed through needle 16 from a continuous supply, such as a spool (not shown). To wind a pole of stator 10, leads 22 and 24 of the wires pass through needle 16 and are temporarily held by temporary terminating start lead holders 26 and 28, respectively. Needle 16 alternately reciprocates and oscillates around the stator pole, using a conventional winding motion (typically without shrouds), to form coils 12. When winding is completed, needle 16 stops at a position A . A lead pull 30 of assembly 18 then descends toward stator 10, passes between wires 31 and 33 extending from needle 16 to the stator pole, rotates to grip a wire 31, and retracts to pull wire 31 past a temporary terminating finish lead holder 32. (Wires 31 and 33 are shown extended past the temporary terminating holders as phantom wires 35 and 37, respectively.) Holder 32 grips and secures this first wire. Gripping assembly 20 then grips and cuts the first wire between needle 16 and lead pull 30 (as shown in FIG. 2 and described in greater detail below). The process is then repeated to secure the second wire 33 in temporary terminating finish lead holder 34. Gripping assembly 20, still gripping wire 31, grips and cuts wire 33 between needle 16 and lead pull 30. The portion of wires 31 and 33 gripped by gripping assembly 20 become the start leads of the next stator to be wound in the winding machine. Needle 16 moves to position B to align the start leads of wires 31 and 33 with holders 26 and 28 of the next stator to be wound. Housing 14 preferably slides between the positions identified as C and D (FIG. 2). Housing 14 advances to position C so that gripping assembly 20 may bring start leads 22 and 24 in contact with start lead holders 26 and 28. The stator is wound with housing 14 in position C. The finish leads also may be attached to holders 32 and 34 when housing 14 is at position C. The housing preferably retracts to position D to clear needle 16, and to create a space for lead pull 30 to descend between needle 16 and stator 10. Once the finish leads (indicated in their cut condition by reference numbers 36 and 38 in FIG. 2) are cut and secured in holders 32 and 34, housing 14 and stator 10 can be removed from the winding station. The start leads and finish leads (shown prior to cutting) of coils 12 are precisely positioned in start lead holders 26 and 28 and temporary terminating holders 32 and 34, respectively, to facilitate automated processing of the leads at a subsequent station in the assembly line. In accordance with the principles of this invention, stator winding needle 16 is provided with two separate wire delivery channels 40 and 42, one for each wire. The separate delivery channels which are transverse to the longitudinal axis (x) and separated by a predetermined distance ensure that wires 31 and 33 exit needle 16 in predetermined, distinct directions when needle 16 is stopped to permit lead anchoring. Thus, a conventional winding machine can be adapted to wind two coils per pole, by passing wires 31 and 33 from their respective tensioners (not shown), through the main shaft of needle 16, and then threading the wires through the respective wire outlets of needle 16. Lead pulling assembly 18 includes lead pull 30 (disposed along an axis 44), cylinders 46 and 48, and a double cylinder 50. Double cylinder 50 controls the rotation of lead pull 30 about axis 44. Lead pull 30 rotates about axis 44, in both clockwise and counter-clockwise directions, to grasp a predetermined one of wires 31 and 33, between needle 16 and stator 10. Cylinder 48 translates lead pull 30 along axis 44, toward stator 10, to grasp a wire. The lead pull is translated away from the stator to draw extra wire from needle 16, and to position wires 31 and 33 (also labeled 35 and 37, respectively) against temporary terminating holder 32 or 34 of housing 14. Cylinder 46 translates gripping assembly 20 and lead pull 30 across the face of stator 10, to align the gripping assembly and lead pull with holders 32 and 34 (for attaching the leads). Thus, wires 31 and 33 are placed adjacent to the gripping portion of holders 32 and 34 (which are opened by an actuator not shown). An illustrative embodiment of lead pulling assembly 18 will now be described. One skilled in the art will appreciate that assembly 18 generally performs the functions of rotating lead pull 30, translating lead pull 30 along axis 44, and translating the lead pull across the face of stator 10. It will also be appreciated that these functions could be implemented using a variety of apparatus, only one of which is described below. Cylinder 46 is coupled to the frame 51 of the winding machine. Frame 51 supports the entire lead pulling assembly. Cylinder 46 translates lead pull 30 perpendicular to axis 44, across the face of stator 10. The shaft of cylinder 46 is coupled to a slide 52, which supports lead pull 30 via support block 54. Slide 52 also supports cylinder 48. A coupling 57 of slide 52 slides on a guide 56 when the shaft of cylinder 46 extends or retracts. Cylinder 48, mounted on slide 52, causes lead pull 30 to translate along axis 44. The shaft 58 of cylinder 48 is connected to a support member 60. Member 60 supports the outer ring of a bearing 62. The rotatable portion of bearing 62 is rigidly coupled to a cylindrical portion 66 of lead pull 30 via a pin and collar assembly 64. Extending shaft 58 causes lead pull 30 to translate upwards, away from the stator. Retracting shaft 58 translates lead pull 30 toward stator 10 for insertion between wires 31 and 33. The tip of lead pull 30 is preferably tapered to facilitate insertion between the two wires. Cylindrical portion 66 of lead pull 30 is mounted to rotate on bearing 62. A gear 68 fixed to cylindrical portion 66 engages a rack 70, which is connected to a first output shaft 72 of double cylinder 50. A second shaft 74 of cylinder 50 is connected to support member 60. Actuating the shafts of cylinder 50 moves rack 70 forward or backward from a central position, causing lead pull 30 to rotate in a clockwise or counter-clockwise direction (as indicated by reference numbers 76 and 78, respectively). Referring now to FIGS. 2-4, gripper assembly 20 includes a gripper head 80 which is fixed to a post 82. Post 82 is rigidly connected to an arm 84, which is coupled between a double cylinder 86 and a support structure 88. Structure 88 preferably is mounted on slide 52 of lead pulling assembly 18 (FIG. 1), such that the gripper assembly can be translated by cylinder 46 to align start leads 22 and 24 with start lead holders 26 and 28. Cylinder 86 rotates arm 84 about a pin 90 to move gripper head 80 in an arc between a rest position 92, an intermediate position 94, and an extended position 96. A first shaft extension of double cylinder 86 rotates gripper head 80 from position 92 to position 94, to grip and cut a wire between lead pull 30 and needle 16. A second extension of double cylinder 86 advances gripper head 80 to position 96, to insert initial leads 22 and 24 into holders 26 and 28. Gripper head 80 includes two seats 98 and 100 for separately receiving and gripping wires 31 and 33. Once a lead has been inserted into its respective seat (by moving the gripper head to position 94), a cylinder plunger 102 or 104 of the respective seat is actuated to press the lead against a member 106, to grip the lead. A cutter blade 108 cuts the portion of wire which stretches from the lead pull to the gripper head. A cylinder 110, coupled to cutter blade 108 by a pivoted lever 112, advances blade 108 across seats 98 and 100 to cut wires 31 and 33. Cutter blade 108 may be provided with two cutting edges, so as to cut when the piston of cylinder 110 extends or retracts. Gripper head 80 then rotates back to position 92, holding a single wire extending from lead 16. This wire becomes a start lead 22 or 24 of the next stator to be wound. Lead pull 30 again translates along axis 44 toward the stator to grasp the remaining wire. Lead pull 30 rotates to grip the remaining wire, and retracts along axis 44. The second lead is gripped by the seat 98 or 100, and cut by blade 108. Gripper head 80 now holds two start leads from needle 16, and is ready to initiate the winding process on a successive stator to be positioned in the winding station. When an unwound stator is positioned at the winding station, gripper head 80 translates across the stator face (by the action of cylinder 46 of FIG. 1) to align start leads 22 and 24 with start lead holders 26 and 28. Housing 14 is advanced to position C, as described above. Needle 16 may be rotated to position B (FIG. 1) to better align leads 22 and 24 with holders 26 and 28. Gripper head 80 is then rotated to position 96 to insert the leads into holders 26 and 28. Referring to FIGS. 1 and 3, holders 26, 28, 32, and 34 typically may be operated by external actuators (not shown). Each holder includes a stationary member 114, a movable member 116 (shown open in FIG. 3) surrounded by a housing 118, an end member 120, and a spring 122. The external actuator acts on end member 120 to compress spring 122 to open the holder. When a lead has been placed against member 116, the actuator may release spring 122, capturing the lead. The action of spring 122 on housing 118 and end member 120 keeps the lead securely within the holder. In an alternative embodiment of the invention, instead of temporarily anchored the wire coils on housing 14, the coils are temporarily anchored elsewhere (e.g., on the stator). If desirable, an intermediate connection of the leads can be made to a terminal, such as terminal 124. A hook mechanism 126 may be provided to establish the intermediate connection. Hook mechanism 126 extends to capture one of wires 31 and 33, and then retracts to position the captured wire adjacent terminal 124. The intermediate connection may be formed for one or both of wires 31 and 33 according to the method described in commonly-owned, U.S. patent No. 5·233·751, filed May 25, 1990. If one of wires 31 and 33 are not intermediately connected and inadvertently loosens, a wire tensioner associated with that wire may tighten the wire as necessary. In another alternative embodiment, the coils are permanently terminated on the stator while the stator is still located in the winding station. In such instances, the terminals of stator 10 typically are positioned such that complicated manipulation is not required to mount the leads in the terminals (e.g., as shown in FIG. 5). Referring to FIG. 5, lead pull 30 grasps wire 31, and then rotates from position E to position F , to align axis 44 with a terminal receptacle 128 (shown in phantom). Prior to rotating lead pull 30, a wire guide 130 is positioned over terminal 128. When the lead pull moves across guide 130, wire 31 contacts the guide and passes along the surface of the guide until the wire is aligned with the terminal receptacle. Moving lead pull 30 toward housing 14 (or moving the housing toward the lead pull) brings the wire into the opening of the terminal receptacle. An inserting device (not shown) then drives wire 31 into the clamping portion of terminal 128. Gripper head 80 then grips and cuts the wire between terminal 128 and needle 16, forming an initial lead of the next stator to be wound. This process is repeated to terminate wire 33 in terminal 132. To terminate the start leads of the next stator to be wound, gripper head 80 crosses the face of the next stator and inserts the initial leads into the initial lead terminal receptacles 134 and 136 (of the next unwound stator). The gripper head may place the initial leads into guides (not shown) positioned over terminals 134 and 136. The inserting device will then drive the initial leads into the clamping portions of receptacles 134 and 136. A hook mechanism, such as hook mechanism 126, may be used to grip predetermined leads and align the leads with a wire guide when more complicated wire manipulation is required. An inserting device (not shown) will then drive the wire into a clamping portion of the terminal. Gripper head 80 grasps the terminated wire between the terminal and needle 16, and cuts the wire as previously described. To permanently attach the start lead to stator 10, hook mechanism 126 grips the wire between gripper head 80 and needle 16, and aligns the wire with a guide (not shown) positioned over the start lead terminal receptacle. The inserting device then inserts the start lead into the clamping portion of the terminal. Thus a stator winding machine for winding a stator with two wires simultaneously is provided. | Apparatus for simultaneously winding two wires (31, 33) on a pole of a stator (10) having a longitudinal axis (x), comprising a needle (16) for simultaneously winding said pole of said stator with said two wires, said needle having a separate delivery channel (40, 42) for each of said two wires; a lead pull assembly (18, 30) having a lead pull (30) for engaging at least one of said two wires, said apparatus being characterized in that said separate delivery channels for each of said two wires are laterally spaced from one another by a predetermined distance transverse to said longitudinal axis (x) which is sufficient to keep said two wires at a separation distance from one another to allow said lead pull (30) to capture at least one of said two wires by passing between said two wires, and further comprising means (48) for causing said lead pull (30) to pass between said two wires in order to capture and draw said at least one of said two wires adjacent to means (32,34) for securing said at least one of said two wires. The apparatus defined in claim 1 wherein said needle (16) reciprocates relative to said stator substantially parallel, to said longitudinal axis (x) to wind said wires on said pole. The apparatus defined in claim 1 or 2 wherein said lead pull (30) comprises a longitudinal member insertable between said two wires where said two wires are at a separation distance from each other in order to capture said at least one of said two wires. The apparatus defined In claim 3 further comprising means (48, 58) for inserting said longitudinal member (30) between said two wires where said two wires are at a separation distance from each other; means (50, 68, 70) for rotating said longitudinal member to capture said at least one of said two wires; and means (48) for retracting said longitudinal member so that said at least one of said two wires becomes captured by said longitudinal member. The apparatus defined in claim 4 further comprising: first means (46, 48) for manipulating said longitudinal member with said captured wire to position said captured wire so that a first wire securing means (32) can hold said captured wire; and second means (80) for passing said captured wire to said first securing means. The apparatus defined in claim 5 wherein said second means comprises means (108) for cutting said captured wire between the capturing point of said captured wire and said needle. The apparatus defined in claim 6 wherein said second means further comprises means (102) for gripping said captured wire which extends to said needle. The apparatus defined in any of the preceding claims wherein said lead pull (30) captures the other of said two wires after capturing said at least one of said two wires. The apparatus defined in claim 7 being characterized In that said second means is provided with a first gripping means (102) for gripping a first wire of said two wires and a second distinct gripping means (104) for gripping a second wire of said two wires. The apparatus defined in claim 9 being further characterized in that said needle resumes winding of a new stator pole after gripping said first and said second wire by said second means. The method of winding a pole of a stator (10) having a longitudinal axis (x) wherein two wires (31,33) are wound simultaneously on said pole, by delivering said two wires from a needle (16), the method being characterized in that said winding step comprises the step of winding said wires along respective predetermined laterally spaced directions leading from said winding needle; capturing at least one of said two wires along the predetermined direction of said at least one of said two wires by passing between said two wires (31,33) and drawing said at least one of said two wires adjacent to a means (32) for securing said at least one of said two wires; and securing said at least one of said two wires to said securing means. The method defined In claim 11 wherein said winding step further comprises the step of capturing the other of said at least one of said two wires along the predetermined direction of said other wire and drawing said wire adjacent to a means (26) for securing said other wire; and securing said second wire to said securing means. The method defined in any of the preceding claims 11-12 wherein said winding step further comprises the step of cutting said two wires after said securing step. The method defined in any of the preceding claims 11-13 being further characterized in that between said capturing step and said securing step, said at least one of said two wires becomes gripped. The method defined in any of the preceding claims 11-14 being characterized in that during said winding step, said predetermined laterally spaced directions of said two wires are maintained transverse to said longitudinal axis (x). | AXIS SPA; AXIS S.P.A. | LUCIANI SABATINO; LUCIANI, SABATINO |
EP-0490178-B1 | 490,178 | EP | B1 | EN | 19,970,326 | 1,992 | 20,100,220 | new | H03D13 | H03L7 | H04L7, H03L7, H03D13 | H03D 13/00, H03L 7/095, T04L7:033B | Lock detector for a digital phase locked loop | An improved multiple frequency digital phase-locked loop circuit 10 is described. The improved digital phase-locked loops utilizes a single circuit 12 to effect both phase and frequency adjustments. The multiple frequency digital phase-locked loop effects phase adjustments by selectively combining or subtracting a reference clock signal 30 with a derived programmable clock signal thereby generating a composite digital phase-locked loop clock signal. The multiple frequency provides frequency adjustments by selectively adding or subtracting pulses from the composite clock signal at a rate determined by a programmably controllable clock signal. The improved multifrequency digital phase-locked loop is suitable for use as a tone detector with the addition of a lock detector 22 wherein the phase-locked loop can be programmed for a plurality of known operating frequencies. | Background of the InventionThis invention relates to a lock detector for a digital phase locked loop. A phase locked loop (PLL) circuit comprising a reference oscillator, a reference frequency divider, a programmable frequency divider, a phase comparator for monitoring the difference in phase between the output signal of the two frequency dividers and a lock detector is known from EP-A-0 024 878. Brief Summary of the InventionIn one aspect, the invention provides a lock detector for use in a digital phase-locked loop having an input signal and an output signal, for producing a lock detector output signal in response to the relative phase of the said phase-locked loop input and output signals, comprising: means for generating an out-of-phase signal upon said phase-locked loop input and output signals being out of phase; means for generating a clock signal in the form of high frequency pulses; gating means for gating said high frequency clock pulses to generate gated clock pulses if said out-of-phase signal indicates said phase-locked loop input and output signals are out of phase; first and second divider means for accumulating said gated clock pulses, each being reset at a periodic but different rate respectively, and wherein said first divider accumulates pulses over a relatively short period relative to the period of the high frequency clock pulses and said second divider accumulates overflow pulses output from said first divider, wherein said overflow pulses output from said first divider comprise out-of-lock pulses which indicate that said phase-locked loop is out of lock, and are accumulated by said second divider over a relatively long period relative to the period of the high frequency clock pulses; and lock indicator means for indicating a locked condition in the event said second divider has not accumulated a predetermined number of out-of-lock pulses and wherein said lock indicator means requires several consecutive long period out-of-lock cycles before being set to indicate an out-of-lock condition. A method for detecting a locked condition in a digital phase-locked loop having input and output signals as defined in claim 4 is also provided. Brief Description of the DrawingsFigure 1 is a block diagram of a multiple frequency digital phase-locked loop incorporating the present invention. Figure 2a is an electrical schematic of the programmable divider, the phase comparator, and the phase and frequency adjust network of the multiple frequency digital phase-locked loop of Figure 1. Figure 2b is an electrical schematic of the digital phase-locked loop frequency divider and lock detector circuit of Figure 1. Figure 3a is a timing diagram detailing the operation the frequency adjustment portion of Figure 2a. Figure 3b is a timing diagram detailing the operation of the phase adjustment portion of Figure 2a. Figure 3c is a timing diagram detailing the operation of the lock detect circuit of Figure 2b. Detailed Description of the DrawingsFigure 1 shows a block diagram of the multiple frequency digital phase-locked loop (DPLL) 10, constructed in accordance with the present invention. The digital phase-locked loop comprises a phase and frequency adjust network 12 which is coupled to a digital divider 16, a bandwidth control 20, and AND gate 30 and an input clock terminal 14. The bandwidth control 20 is also coupled to a phase comparator 18. The phase comparator 18 accepts inputs from the output of the digital divider 16 as well as the received data signal. In operation, a reference clock signal from a signal source is coupled to the phase and frequency adjust network 12 through terminal 14. The reference clock signal is additionally coupled to digital divider 26 and the programmable digital divider 28. The phase and frequency adjust network 12 generates a shifted clock signal from the reference clock signal, and generates frequency shifts by selectively adding or subtracting the reference clock signal and the shifted clock signal at a rate determined by the programmable clock from signal AND gate 30, which is controlled by programmable signals Y, and Z. The phase and frequency adjust network also effects frequency shifts as directed by a programmable control signal X, as well as the signals generated by the bandwidth control 20. The phase and frequency adjust network 12 provides a composite clock signal E which is coupled to digital divider 16. The digital divider 16, frequency divides the composite clock signal E and provides the output signal of the digital phase-locked loop. The output of digital divider 16 is coupled to one input of the phase comparator 18. A second input of phase comparator 18 is coupled to a received data signal. The phase comparator provides a signal which is related to the relative phase of the output of the DPLL and the received data signal. If the DPLL output signal and the input data signal are not exactly in phase, an output is indicated. The operation of the phase comparator will be discussed in more detail later. The multiple frequency digital phase-locked loop is additionally provided with two frequency dividers 26 and 28 which are coupled between the clock input 14 and an AND gate 30. The digital divider 28 accepts programmable inputs Y, Z which cause divider 28 to effect a variety of divide ratios. The programmable controls Y, Z, as well as a control X cooperate with a bandwidth control 20 and cause the bandwidth control to vary the loop correction bandwidth in accordance with loop operating frequencies. The programmable control X also cooperates with the phase and frequency adjust network 12 and controls the direction of frequency corrections by the digital phase-locked loop. The inputs to phase comparator are also coupled to an EXCLUSIVE-OR gate 24 which is further coupled to a lock detector 22. As mentioned earlier, the multiple frequency DPLL cooperates with three programmable control inputs X, Y, Z. The programmable control signals cooperate with the bandwidth control 20, the phase and frequency adjust 12 and the programmable digital divider 28 and direct the center frequency and bandwidth of the multiple frequency DPLL. In the preferred practice of the present invention, it is desirable to provide a first operating frequency with a wide band capability and several other operating frequencies with a narrow band capability. This feature allows the testing a number of operating frequencies while having the multiple frequency DPLL programmed to a known single frequency. The bandwidth control 20 effects a loop bandwidth variation by altering the number of digital pulses which are added or subtracted from the composite clock, while effecting loop phase adjustments. The programmable control signals Y, Z also control the loop operating frequency in the following manner. The composite reference clock signal is coupled, through the phase and frequency adjust network 12, to divider 16. In the preferred embodiment, a clock reference signal of 1.92 MHz is provided, and with no other manipulation, divider 16 would provide a loop operating frequency of 6000 Hz. Therefore, the multiple frequency DPLL is capable of making approximately 6000 corrections per second. In addition, dividers 26 and 28 are coupled to the 1.92 MHz reference clock and to AND gate 30 to provide an output signal which can be several possible frequencies, based on the programmable control signals Y, Z. The output frequency of AND gate 30 is equivalent to fEderived = N200 (freference) where N is provided by programmable controls Y, Z as shown in Figure 1. Therefore, for example, for N=1, this output is 1.92 MHz200 = 9600 Hz the programmable clock signal is coupled to the phase and frequency adjust network 12 which either adds, subtracts, or possibly neither, shifted reference clock pulses from the 1.92 mHz reference clock signal at a rate determined by the programmable clock signal. Therefore for N=1 the loop operating frequency would calculated as follows: 1.92 MHz + 9600 Hz320 = 6030 Hz As mentioned earlier, for the frequencies described, the multifrequency DPLL can make approximately 6000 corrections/second. If the phase and frequency adjust network adds or subtracts 6000 pulses/second from the reference clock signal, the digital phase locked loop can compensate for phase disparities according to the following relationship: 1.92 MHz + 6000 Hz320 = 6018.75Hz Therefore, if the bandwidth control 20 adds or subtracts 1 pulse per correction, the loop bandwidth can be defined as: 6000 Hz ± 18.75 Hz The phase comparator 18 can be programmed to make phase comparisons on the positive edges of f1 or on both positive and negative edge of fo when X Y Z = 0 0 0 respectively. The latter condition carries approximately 12000 corrections to be made per second and is used in conjunction with additional pulse per correction being added or subtracted to expand the DPLL lock bandwidth. 1.92 + 212000320 = 6000 ±75 Hz The programmable control signals X, Y, Z instruct the bandwidth control 20 to add/subtract 1,2, or 4 pulses per correction, therefore, according to the preferred practice of the present invention, and the relationships above, the multifrequency DPLL can exhibit loop bandwidths of 18.75 Hz, 75 Hz or 150 Hz under the control of the bandwidth control circuit 20. The relationship between the programmable control signals X, Y, Z and loop operating frequency and bandwidth is shown below in Table 1. X Y Z Center Frequency Mode 1 Bw+/- Mode 2 Bw+/- 000600075 Hz150 Hz 001597018.75 Hz18.75 Hz 010594018.75 Hz18.75 Hz 011591018.75 Hz18.75 Hz 100600018.75 Hz18.75 Hz 101603018.75 Hz18.75 Hz 110606018.75 Hz18.75 Hz 111609018.75 Hz18.75 Hz Figure 2a shows an electrical schematic of the phase and frequency adjust network 12, the phase comparator 18, the bandwidth control 20, and the digital dividers 26, 28 of Figure 1. The associated timing diagrams for Figure 2a are shown in Figure 3a and Figure 3b. According to Figure 2a, a reference clock signal is coupled to terminal 14 and provides the operating reference frequency for the multiple frequency DPLL. The reference clock signal is processed by flip-flop 101 which is further coupled to NOR gates 103, 105. The flip-flop 101 and NOR gates 103,105 provide a reference clock, signal B, and a shifted reference clock signal, signal A, which are shown in Figure 3a. The output terminal of NOR gate 105, or signal A, is coupled to a flip-flop 107 which forms an input to the bandwidth control 20. Signal A is also provided to a multiplexer 109 which is also associated with the bandwidth control 20. Signal A is additionally coupled to a flip-flop 111 and an AND gate 113 which form a portion of the phase and frequency adjust network 12. The output of NOR gate 103, signal B, is coupled to flip-flops 115, 117, 119, 121, 123 which form a portion of frequency divider 26 of Figure 1. In addition, signal B is coupled to flip-flops 125, 127 and 129 which form a portion of the programmable divider 28. Signal B is additionally coupled to flip-flop 131 and multiplexer 133 in the bandwidth control circuit 20. Signal B is further coupled to AND gate 135 in the phase and frequency adjust network 12. Referring still to Figure 2a, the phase comparator 18 comprises flip-flops 137, 139, 141, 143, 145, 147 and 149, OR gates 151 and 153, AND gate 155, and NOR gate 157 which are coupled as shown in Figure 2a. Specifically, flip-flop 137 is coupled to flip-flops 141 and 143 which form a portion of the phase advance circuitry of the phase comparator 18. Likewise, flip-flop 147 is coupled to flip-flops 145 and 149 and form a portion of the phase retard circuitry of the phase comparator 18. Flip-Flop 139 is coupled to flip-flops 143 and 145 and provides signals to both the phase advance and phase retard portions of comparator 18. OR gate 151 is coupled to flip-flops 141 and 149 and provides a first output signal for the phase comparator 18. OR gate 153 is coupled to flip-flops 143 and 145 and provides a second output signal for the phase comparator circuit. AND gate 155 is coupled to flip-flops 145 and 149 and cooperates with NOR gate 157 which is coupled to flip-flops 141 and 143 to provide a reset function to the phase comparator 18. It should be noted that flip-flops 137, 139, 141, 143, 145, 147 and 149 are D-type flip-flops which are well known. The operation of the phase comparator 18 will be explained in conjunction with Figure 3b. Referring now to Figure 3b, there is shown two timing signals fo, and 2fo. These signals are derived from the clock reference signal by the digital divider circuit 16 of Figure 1, which will be discussed more fully below. The three derived timing signals fo, fo and 2fo of Figure 3a are coupled to the phase comparator 18 of Figure 2a as shown. Specifically, timing signal fo is provided to the D terminal of flip-flop 139 and the C terminal of flip-flop 137. The fo timing signal is provided to the C terminal of flip-flop 147. The 2fo timing signal is provided to the C terminal of flip-flop 139. The incoming data signal, fo, is coupled to the D input terminals of flip-flops 137 and 147. Referring now to Figures 2a and 3b, signal G of Figure 3b corresponds to the Q output signal of flip-flop 137 of Figure 2a. Signal H of Figure 3b corresponds to the Q output terminal of flip-flop 147 of Figure 2a. Signal I of Figure 3b corresponds to the Q output terminal of flip-flop 141 of Figure 2a. Signal G of Figure 3b corresponds to the Q output terminal of flip-flop 137 of Figure 2a. As mentioned earlier, the purpose of phase comparator 18 is to provide output signals which indicate the relative phase of the reference clock signal and the received data signal. The phase locked loop output signal fo is used to sample the received data signal fi. Three possible phase relationships may exist between these two signals. The signals may be in phase, or the phase locked loop output signal may be leading or lagging the incoming data signal. Flip-flops 137 and 139 provide a comparison of the incoming data signal and the DPLL output signal. If the incoming data signal (fi) leads the divider 16 output signal as shown in Figure 3b, flip-flop 137 will cause signal G to be set high. Since flip-flop 137 is clocked directly by fo, signal G will be set high on the leading edge of a transition in fo. Flip-flop 139 is coupled to fo and is clocked by a 2fo signal, therefore, for every positive transition in fo, signal L will be set high, however, 2fo will be set high 1/2 cycle after fo was set high because of the 1/2 cycle delay generated by flip-flop 139. Actual phase corrections are effected on a positive transition in signal L, therefore, it is desirable to delay signal L to prevent phase corrections from occuring on an edge of the fo control clock. For the phase condition shown in Figure 3b and described above, a positive transition in signal G followed by a positive transition in L will cause the output of flip-flop 141 to be set high (signal I). A high value in signal I indicates that fi is leading fo and therefore pulses should be added to the composite system clock to cause the phase of fo to advance. If the phase of the DPLL output signal leads the received data signal, the output of flip-flop 143, signal I, will be set high indicating pulses should be subtracted from the composite system clock to cause fo to retard. Flip-flops 145, 147 and 149 operate in an analogous fashion, however flip-flop 147 is clocked on the negative edge of fo and generates phase comparison signals I' and I' which are delayed with respect to signals I and I. Flip-flops 145, 147 and 149 are held in reset by the bandwidth control circuit 20 through AND gate 155. If the digital phase-locked loop circuit is set for narrow band operation, one phase comparison per period of fo is required. If the digital phase-locked loop is set for wide band operation, flip-flops 145, 147 and 149 are activated and the phase comparator 18 provides two phase comparisions per comparison period. That is one comparison on the leading edge of fo and one on the trailing edge of fo. Flip-flop 141, 143, 145 and 149 are also reset whenever a phase adjustment has been made, through AND gate 155 and NOR gate 157. Referring now to Figure 2a, the DPLL digital divider 28 is shown. Digital divider 28 is clocked by system clock B and provides a variable divide ratio based on programmable system controls Y, Z. Digital divider 28 comprises flip-flops 125, 127 and 129 as well as multiplexer 159 and AND gates 161, 163 and 173, NAND gates 167, 169 and 171, inverter 165, and EXCLUSIVE-OR gates 177 and 175, coupled as shown in Figure 2a. Digital divider 26 comprises flip/flops 115, 117, 119, 121, 123 and NAND gates 181, 183, 185, 187 and 189 coupled as shown in Figure 2a. Divider 26 provides a fixed divide ratio of 25. Divider 28 provides a variable divide ratio from 1 to 8. The outputs of dividers 26, 28 are combined by AND gate 30 in a dual-modulus fashion to provide a composite divide ratio of 200/N wherein N is controlled by programmable controls Y, Z. It should be noted that digital dividers of this type are well known and several divider configurations would function satisfactorily. Therefore dividers 26, 28 may be any suitable conventional 200/N digital divider and is not limited to the specific configuration shown in Figure 2a. Referring still to Figure 2a, there is shown the phase and frequency adjust network 12 of Figure 1. The phase and frequency adjust network 12 cooperates with programmable control signal X, the derived programmable clock signal, the reference clock signal B, the shifted reference clock signal A, and the bandwidth control 20 output signal, and adds or subtracts pulses to the DPLL reference signal B to compensate for phase disparities or frequency changes. The phase and frequency adjust network 12 comprises flip-flops 111 and 197 which effect frequency adjustments and flip-flops 209 and 211 which effect phase adjustments. The phase and frequency network additionally includes inverters 191, 195, 205, NAND gates 193, 203, 113, 135, and 217, AND gates 201 and 207, NOR gates 215 and 157 and OR gate 213 coupled as shown in Figure 2a. As mentioned earlier, OR gates 151 and 153 in the phase comparator 18 provide an output signal wherein an active signal appearing at the output of OR gate 151 indicates pulses should be added to the composite clock, signal E, to compensate for phase and an active output appearing at the output of OR gate 153 similarly indicates pulses should be subtracted to compensate for phase. The phase and frequency adjust network 12 also cooperates with programmable signals X, Y, Z, to effect frequency shifts in the operating frequency of the digital phase-locked loop. The phase and frequency adjust network 12 provides phase and frequency adjustments by combining or subtracting a reference clock, signal B, and a shifted reference clock, signal A, to provide a composite clock signal E which operates the digital phase-locked loop divider 16 of Figure 2b. In addition, the phase and frequency adjust network 12 is coupled to the output of AND gate 30 which produces a programmable clock signal and establishes the adjustment rate of the phase and frequency adjust network 12. The phase and frequency adjust network 12 further cooperates with programmable input signal X which indicates positive or negative frequency shifts from the center loop operating frequency. In operation, the phase and frequency adjust network 12 is continuously provided with clock signal A through flip-flop 111 and NAND gate 113, clock signal B through flip-flop 197 and NAND gate 135, and clock signal C through NAND gates 193 and 203. Programmable input signal X is coupled to inverter 191 which selectively activates either flip-flop 197 (frequency add) or flip-flop 111 (frequency subtract), depending on the state of signal X. If programmable control signal X is low, then the derived programmable clock signal C will be coupled to flip-flop 197 through NAND gate 193 and inverter 195. In a similar fashion, if if programmable input signal X is high, then the derived clock signal C is coupled to flip-flop 111 through NAND gate 203 and inverter 205. If the programmable derived clock signal C appears at the delay input of flip-flop 197, clock signal B will allow signal C to clock through flip-flop 197 to OR gate 213. The next B clock pulse will reset flip-flop 197, thus gating a single pulse through flip-flop 197. The output of OR gate 213 is normally low, except when pulses are to be added to the main system clock B, therefore, when the output of flip-flop 197 is high, clock A will be summed with clock signal B through NAND gates 113, 135 and 217. Pulses are subtracted from the clock B in a similar fashion. If programmable input signal X is low, the programmable derived clock signal C will be coupled to flip-flop 111 through NAND gate 203 and inverter 205. Programmable derived clock signal C is clocked through flip-flop 111 with each positive transition of clock signal A, allowing the output to go high, thus forcing the output of NOR gate 215 low. When the output of NOR gate 215 goes low, NAND gate 135 will be disabled and the main system clock B will be isolated from the composite clock signal E. Phase compensations are also effected utilizing OR gate 213, NOR gate 215 and NAND gates 113, 135 and 217. As mentioned earlier, the output of OR gates 151 and 153 comprise phase adjust indication signals. That is, if the output of OR gate 151 is active, a positive phase adjustment is required. If the output of OR gate 153 is active, a negative phase shift is required. Referring now to Figure 2a, the phase comparator 18 cooperates with the phase and frequency adjust network 12 through AND gates 201 and 207. AND gates 201 and 207 also cooperate with NAND gates 193 and 203 and provide arbitration between phase and frequency adjustments. If a frequency adjustment is presently in process, AND gates 201 and 207 will prevent the phase adjustment from being effected until the frequency adjustment has been completed. This feature will be discussed in more detail later. Assuming that a frequency adjustment is not currently in process, the phase comparison signals I, I, I' or I', will be coupled to the delay inputs of flip-flops 209, 211 respectively. The phase adjust flip flop 209 and 211 also cooperate with clock signals A, B through the bandwidth control 20. The bandwidth control 20 will be discussed in more detail below. Briefly, however, the bandwidth control circuit 20 provides a control for the number of pulses to be added or subtracted to the composite clock signal E for phase comparisons. The bandwidth control circuit effects variable pulse control by providing a variable clock signal to flip-flop 209 and 211. If the delay input of flip-flop 209 is active, every positive transition of the signal appearing at the clock terminal will cause signal K to go high, activating the output of OR gate 213 which enables NAND gate 113. As mentioned above if NAND gate 113 is enabled, pulses will be added to composite system clock E, wherein the actual number of phase pulses added is controlled by the clock terminal of flip-flop 209. If a negative phase shift is required, pulses must be subtracted from the composite clock signal E. If the output of OR gate 153 is active, a negative phase adjustment is currently being effected, the output of NAND gate 203 is high, enabling AND gate 207, which couples the output of NOR gate 153 to flip-flop 211. Flip-flop 211 cooperates with the bandwidth control 20 through the clock terminal of flip-flop 211. With every positive transition of the bandwidth control clock generated in the bandwidth control circuit, the output of flip-flop 211 will go high if a negative phase shift is required. If the output of flip-flop 211 is high, the output of NOR gate 215 will go low disabling NAND gate 135, thus preventing the main clock signal B pulses from being combined with the composite system clock signal E. As mentioned earlier, phase adjustments will be delayed if a frequency adjustment is currently being effected. Referring now to the phase comparator 18 of Figure 2a, the outputs of flip-flops 141, 143, 145 and 149 comprise signals indicating phase adjustments. Once a phase adjustment signal appears, the signal will be maintained until the appropriate flip-flop is reset. The reset signal indicates that a phase adjustment has been completed. The phase adjust reset signal is derived from the phase and frequency adjust network 12 by NOR 157. The outputs of phase adjust flip-flops 209 and 211 are coupled to the inputs of NOR gate 157 such that whenever a phase adjustment has been completed, on the next subsequent bandwidth control clock, the output of NOR gate 157 will go low, resetting flip-flops 141 and 143. Referring still to Figure 2a, the bandwidth control 20 of Figure 1 is shown in detail. The bandwidth control 20 is controlled by programmable control signals X, Y, and Z and programmable switches 223 and 225. The bandwidth control 20 provides a variable control determining the number of pulses to be added or subtracted during phase adjustments. Specifically the bandwidth control 20 can effect phase adjustments of one, two or four pulses based on programmable input signals. As mentioned earlier, the bandwidth control 20 provides a variable clock signal to flip-flops 209 and 211 of the phase and frequency adjust network 12. The bandwidth control 20 comprises flip-flops 131 and 221 coupled as a frequency divider, flip-flops 107 and 219 also coupled as a frequency divider, NOR gate 227 programmable switches 223 and 225 and multiplexers 133 and 109. In operation, flip-flops 131 and 221 are coupled to clock B and provide signals at one-half and one-forth the rate of reference clock signal B. Flip-flops 107 and 219 are coupled to clock signal A and provide signals at one-half and one-forth the rate of clock signal A. The divided B and A clock signals are coupled to multiplexer 133 and 109 through programmable switches 223 and 225 respectively. The programmable switches 223 and 225 control which divided clock signal is coupled to multiplexer 133 and 109. If the mode one position is selected, a higher rate divided clock signal will be coupled to the phase adjust flip-flops 209 and 211, causing the Q outputs of flip-flops 209 and 211 to be set and cleared more quickly thereby reducing the number of pulses to be added or subtracted from the composite system clock, signal E. If a relatively larger number of pulses are added or subtracted from the composite system clock, larger phase shifts will be effected, thus a wider bandwidth capability is provided to the loop. NOR gate 227 is coupled to the programmable loop control signals X, Y, Z and has an output coupled to the clock terminals of multiplexers 133 and 109. A high output signal at the output of NOR gate 227 indicates that the digital phase locked loop has been set for wide band operation. This output signal causes multiplexers 133 and 109 to select the programmable switches 223 and 225 which have been previously set for a required system configuration, causing flip-flops 209 and 211 to effect multiple pulse corrections. If the output of NOR gate 227 is low, the multiple frequency digital phase-locked loop will be set for narrow band operation and multiplexers 109, 133 will select signals A and B causing single pulse corrections. Referring now to Figure 2c, there is shown a detailed electrical schematic of the digital divider 16 and the lock detector 22 of Figure 1. The various timing signals of Figure 2b are shown in Figure 3b and Figures 2a and 3c and will be referred to interchangeably. The frequency divider 16 of Figure 1 is coupled to the composite clock signal E of Figures 2a and 3a. The frequency divider 16 divides the composite clock signal E to provide the operating clock signal fo, of the digital phase locked loop 10. In addition, the frequency divider 16 provides a plurality of derived clock signals to operate the lock detector 22. The frequency divider 16 comprises flip-flops 301, 303, 305, 307, 309, 311, 313, 315, 317 and NOR gate 319 coupled as shown in Figure 2b, which is a well-known frequency divider configuration. The output of flip-flop 303 provides a signal at one-fourth the frequency of composite clock signal E which is used to operate several portions of the lock-detector 22. In addition, flip-flops 311, 313 and 315, and NOR gate 319 form a divide-by-5 divider 310 which generates a signal of intermediate frequency with respect to the whole of divider 16. The combined outputs of divider 310 comprise a clock pulse centered around fo, the operating clock signal of the digital phase-locked loop 10. According to the preferred practice of the present invention, divider 16 provides an output signal which has been divided by 320 with respect to the composite clock signal E. It should be noted that many frequency divider configurations would function satisfactorily with the present invention, and the present invention is not limited to the specific configuration shown in Figure 2b. Referring still to Figure 2b, the lock detect circuit 16 is shown in detail. The lock detector 16 compares the output clock signal of the digital phase lock loop, fo, and a received data signal, fi, and provides an indication when the two signals are in phase. The lock detector circuit 22 allows the digital phase locked loop of the present invention to be used as a tone detector. Since the digital phase locked loop can be programmed to operate at a specificly known frequency, the lock detector 22 can provide an indication that a specific frequency, within the operating bandwidth, has been detected. The lock detect circuit inputs are provided by EXCLUSIVE-OR gate 329 which is coupled to the incoming data signal, fi, and the frequency divider 16 output signal fo. The output of EXCLUSIVE-OR 329 is high whenever fo and fi are out of phase. The output of EXCLUSIVE-OR 329 is coupled to a multiple input AND gate 331. AND gate 331 is further coupled to the output of flip-flop 303, which is the composite clock signal E divided by 4, (E/4), as well as the outputs of divider 310. The outputs of divider 310 provide a pulse centered around fo and are used to ensure that the results of the fi and fo comparison are gated-thru AND gate 331 free of fo jitter. When fo and fi are out of phase, the output of EXCLUSIVE-OR 329 will be high and AND gate will allow the (E/4) signal to clock flip-flop 335. If EXCLU- SIVE-OR 329 output is low, AND gate 331 will be disabled and no E/4 clock pulses will reach flip-flop 335. Flip-flops 335, 337, and 339 are coupled in a conventional divider configuration 334 and provide an overflow output pulse every time eight E/4 gated clock pulses are accumulated. Flip-flops 321, and 323 are coupled in a well-known divider configuration. Flip-flops 321 and 323 are coupled to the digital phase locked loop output signal, fo, and provide an output signal at one-fourth the frequency of fo. Flip-flops 325 and 327 and EXCLUSIVE-NOR gate 333 comprise an edge detector circuit which is clocked by the relatively higher frequency clock E/4. Therefore the output of EXCLUSIVE-NOR 333 comprises a signal having a pulse occurring every fourth edge of the divided phase-locked loop output signal. In other words, the output signal of EXCLUSIVE-NOR 333 comprises a signal having a pulse occurring at a rate of fo/2. The output signal of EXCLUSIVE-NOR 333 is used to reset divider 334. If less than 8 (E/4) gated clock pulses have been accumulated during two cycles of the digital phase-locked loop output signal, fo, divider 334 will be reset and no overflow pulses will be generated. In the preferred practice of the present invention, frequency divider 334 can overflow from 0 to 4 times during two fo cycles. The overflow pulses of divider 334 are used to clock divider 341. Divider 341 provides an output pulse whenever divider 334 produces 8 overflow pulses. If signals fo and fi are sufficiently out of phase, a significant number of gated (E/4) clock pulses will be accumulated by dividers 334 and 341. The overflow pulses of divider 341 are used to clock and latch flip-flop 351 which forms the input to the lock detect latching circuit 350. The lock detect latching circuit 350 accumulates divider 341 overflow pulses, S, and indicates whether the digital phase locked loop is in a locked state. The lock detect latching circuit 350 is controlled by signals P and R, which comprise the output signals of EXCLUSIVE-OR gates 352 and 354 respectively. Signals P and R are generated by divider 343 and a dual edge detector formed by flip-flop 345, 347 and 349 and EXCLUSIVE-NOR gate 354 and EXCLUSIVE-OR gate 352. Frequency divider 343 is coupled to the output of EXCLUSIVE-NOR 333 which is a pulsed signal having a frequency of fo/2. Divider 343 provides an output pulse every 512 fo pulses. The output signal of divider 343, designated signal O, has a frequency of approximately 11.7 Hz in the preferred practice of the present invention. Flip-flops 345, 347, and 349 are coupled in a shift register configuration which is clocked by the (E/4) clock signal. EXCLUSIVE-OR 352 generates a pulse which occurs at each edge of the signal O pulses. EXCLUSIVE-NOR 354 generates a pulsed output signal R, which is identical in frequency but delayed with respect to signal P. As mentioned earlier, the various timing signals of the lock detect circuit 22 are shown in Figure 3c and are referred to interchangeably with the designations shown in Figure 2b. Referring now to the lock detect latching circuit 350 of Figure 2b, flip-flop 351 provides the first stage of the lock detect latching circuit. If a pulse occurs in signals, flip-flop 351 will be latched and signal T will be set high. Signal T will remain high until flip-flop 351 is reset by signal R. If no signal S overflow pulses have latched flip-flop 351, signal T will remain low. Flip-flop 351 is reset with delayed signal R, therefore if no overflow pulses are received, signal T will remain inactive. If signal T is inactive, the following C clock pulse will clock flip-flop 353 and cause signal U to go high. The high signal U pulse will be clocked into flip-flop 357 by the C clock causing signal W to go high. A logical high state in signal W indicates that the digital phase locked loop is in a locked state. Once signal W has been set high, signal V will be forced low. Signal V clocks flip-flop 357, therefore, if signal V is latched low, flip-flop 357 will be disabled. Whenever signal W is latched high, signal W is necessarily latched low. When the lock detect signal W is active, and the last signal S segment, signal U, indicated a no lock state, flip-flops 359 and 361 will not be reset. Flip-flops 359 and 361 will count C clock pulses as long as they are not reset. The output signal of flip-flop 361 is used to reset flip-flop 357 and causes signal W to indicate an out-of-lock condition. Therefore, for the in-lock indicator signal W, to be reset, two consecutive signal S out-of-lock indications must occur. Additional divider stages may be combined with flip-flops 359 and 361 to provide capability to require additional out-of-lock indicator pulses required for an out-of-lock indication. In summary, an improved multi-frequency digital phase locked-looped circuit has been described. The multi-frequency digital phase-locked loop utilizes common circuitry to effect both frequency and phase adjustments in the digital phase-locked loop. The preferred practice of the present invention contemplates the use of a phase and frequency adjustment network to selectively combine a reference clock signal and a shifted reference clock signal or to selectively delete pulses from the reference clock signal to generate a composite digital phase-locked clock signal. The operating center frequency of the digital phase-locked loop is programmably controlled by periodically adding shifted reference clock pulses to the reference clock signal at a rate determined by the programmably clock signal. The multi-frequency digital phase locked loop can be utilized as a tone detector by the addition of a lock detect circuit. The multi-frequency digital phase-locked loop can be programmed for a known operating frequency. If the lock detect circuit indicates a locked state in the digital phase-locked loop, a known frequency, within the bandwidth of the loop has necessarily been detected. The multi-frequency digital phase-locked loop could also be used as a multi-tone detector by programmably shifting the multi-frequency digital phase-locked loop operating frequency sequentially between required frequencies. Accordingly, other modifications uses and embodiments will be apparent to one skilled in the art without departing from the scope of the appended claims. | A lock detector for use in a digital phase-locked loop having an input signal and an output signal, for producing a lock detector output signal in response to the relative phase of the said phase-locked loop input and output signals, comprising; means for generating (329) an out-of-phase signal upon said phase-locked loop input and output signals being out of phase; means for generating (301, 303) a clock signal in the form of high frequency pulses; gating means (331) for gating said high frequency clock pulses to generate gated clock pulses if said out-of-phase signal indicates said phase-locked loop input and output signals are out of phase; first (334) and second (341) divider means for accumulating said gated clock pulses, each being reset at a periodic but different rate respectively, and wherein said first divider accumulates pulses over a relatively short period relative to the period of the high frequency clock pulses and said second divider accumulates overflow pulses output from said first divider, wherein said over flow pulses output from said first divider comprise out-of-lock pulses which indicate that said phase-locked loop is out of lock, and are accumulated by said second divider over a relatively long period relative to the period of the high frequency clock pulses; and lock indicator means (350) for indicating a locked condition in the event said second divider has not accumulated a predetermined number of out-of-lock pulses and wherein said lock indicator means requires several consecutive long period out-of-lock cycles before being set to indicate an out-of-lock condition. The lock detector of claim 1 wherein said high frequency clock pulses are additionally gated so as to be centered around the middle of each half cycle of said phase-locked loop output signal. The lock detector of claim 1 or 2 wherein a programmable number of consecutive out-of-lock pulses are required to set the lock indicator to indicate an out-of lock condition. A method for detecting a locked condition in a digital phase-locked loop having input and output signals, said method comprising the steps of: a) generating (329) an out-of-phase signal upon said phase locked look input and output signals being out of phase; b) generating (301, 303) a clock signal in the form of high frequency clock pulses and gating said high frequency clock pulses to generate gated clock pulses upon the presence of said generated out-of-phase signal; c) accumulating said gated clock pulses with a first counter (334) wherein said first counter accumulates pulses over a relatively short period relative to the period of the high frequency clock pulses; d) accumulating said first counter output impulses with a second counter (341) wherein said second counter accumulates pulses over a relatively long period relative to the period of the high frequency clock pulses; e) resetting (333, 352) said first and second counters at periodic but different rates respectively; and f) indicating (350) a locked condition in the event that said second counter has not accumulated a predetermined number of pulses, before said second counter is reset. The method of claim 4 further including the step of: g) indicating an out-of-lock condition in the event that said second counter produces an output pulse over a plurality of consecutive relatively long period cycles. | MOTOROLA INC; MOTOROLA, INC. | LEVINE STEVEN N; LEVINE, STEVEN N. |
EP-0490183-B1 | 490,183 | EP | B1 | EN | 19,950,419 | 1,992 | 20,100,220 | new | C07D265 | A61K31, C07D279 | A61P9, A61K31, C07D265, C07D279 | C07D 265/22, C07D 279/08, M07D265:22, M07D279:08 | Benzoxazinone and benzothiazinone derivatives endowed with cardiovascular activity | Benzoxazinone and benzothiazinone derivatives of formula wherein R represents hydrogen, (C₂₋₆)alkyl, (C₅₋₇)cycloalkyl, phenyl, substituted phenyl; R₁ and R₂ independently represent hydrogen, halogen, (C₁₋₄)alkyl, (C₁₋₄)alkoxy or trifluoromethyl; X is oxigen or sulfur; Y is (C₂₋₆)alkylene or (C₅-₇)cycloalkylene; and salts therewith of pharmaceutically acceptable acids. The compounds possess cardiovascular activity with high specificity for the coronary district. | The present invention relates to 2,3-dihydro-4H-1,3-benzoxazin-4-ones and 2,3-dihydro-4H-benzothiazin-4-ones of general formula wherein R is hydrogen, (C₁₋₆)alkyl, cyclopentyl, cyclohexyl, cycloheptyl, phenyl optionally substituted with 1 or 2 groups independently selected from hydroxy, halogen, nitro, (C₁₋₄)alkyl and (C₁₋₄)alkoxy, methylenedioxyphenyl; R₁ and R₂ independently represent hydrogen, halogen, (C₁₋₄)alkyl, (C₁₋₄)alkoxy or trifluoromethyl; X is an oxygen or a sulfur atom, Y represents a (C₂-C₆)alkylene chain or a cyclopentylene, cyclohexylene or cycloheptylene moiety; and the pharmaceutically acceptable acid salts thereof. As intended hereinbelow, the alkyl groups essentially identify methyl, ethyl, propyl, i-propyl, butyl, 2-methylpropyl, n-pentyl, 3-methylbutyl, i-pentyl, n-hexyl and the like, whereas the alkoxy groups are preferably selected from methoxy, ethoxy, propoxy, i-propoxy, butoxy and tert.-butoxy. A (C₂₋₆)alkylene chain may be linear or branched, and is represented by ethylene, 2-methylethylene, 1,3-propylene, 1,4-butylene 2-ethylethylene, 2-methylpropylene, 1,5-pentylene, 2-ethylpropylene, 2-methylbutylene, 1,6-hexylene, 1-ethyl-1-methylpropylene, 3-methylpentylene and the like. A preferred group of compounds comprises those compounds of formula I wherein R is hydrogen, (C₁₋₄)alkyl, cyclopentyl, cyclohexyl or cycloheptyl, R₁ and R₂ independently represent hydrogen, halogen, (C₁₋₄)alkyl or (C₁₋₄)alkoxy, X is an oxygen or a sulfur atom and Y represents a (C₂₋₆) alkylene chain or a cyclopentylene, cyclohexylene or cycloheptylene moiety; and the pharmaceutically acceptable salts thereof. A most preferred group of compounds comprises those compounds of formula I wherein R is hydrogen, R₁ and R₂ independently represent hydrogen, halogen, (C₁₋₄)alkyl or (C₁₋₄)alkoxy, X is an oxygen or a sulfur atom and Y is a (C₂₋₆)alkylene chain, and the pharmaceutically acceptable salts thereof. N-unsubstituted 2,3-dihydro-4H-1,3-benzoxazin-4-ones were described by B.W. Horrom et al., J. Org. Chem., 72, 721 (1950). This article reports that 2,3-dihydro-2-phenyl-4H-1,3-benzoxazin-4-one is endowed with analgesic activity. Other 2,3-dihydro-4H-1,3-benzoxazin-4-ones were described by R.B. Gammil, J. Org. Chem., 46, 3340 (1981). Derivatives of the same heterocycle, but bearing substituents also on the nitrogen atom, were described by J. Finkelstein et al., J. Med. Chem., 11, 1038 (1968); they seem to possess antinflammatory activity. Finally, analogous derivatives bearing an amino group at the 6-position, still having antinflammatory activity, are reported by F. Fontanini et al., Riv. Farmacol. Ter., 4(1), 119 (1973) (Chem. Abs. 73745n Vol.79, page 40, 1973). The compounds of the invention are prepared according to a process comprising, as the first step, the formation of a 2,3-dihydro-1,3-benzoxazine or 2,3-dihydro-1,3-benzothiazine derivative of formula wherein R, R₁, R₂, X and Y have the above meanings, and R₃ is hydrogen or a (C₂₋₄)acyl group, by condensing an amide of formula wherein R₁, R₂, X and Y are as defined above, with an aldehyde of formulaR-CHO III wherein R has the above meanings, or with a derivative or precursor thereof. The condensation usually occurs in an acidic medium, e.g. in a system formed by a strong mineral acid and acetic acid, whereby compounds of formula IV are obtained wherein R₃ is acetyl, or by means of molecular sieves in the presence of sulfonic acids such as, for example, p-toluenesulfonic acid, methanesulfonic acid, α- and β-naphtalenesulfonic acid, phosphoric acids, esters and analogous compounds therof. The use of molecular sieves is preferred when R₁ and/or R₂ represent (C₁₋₄)alkoxy group, in order to avoid the formation of reaction by-products, difficult to be eliminated. The condensation is carried out in the presence of an organic solvent, preferably an inert organic solvent such as, for example, benzene, toluene, nitrobenzene or chlorobenzene, halogenated aliphatic hydrocarbons such as methylene chloride, chloroform, 1,2-dichloroethane or 1,1,2-thrichloroethylene, cyclohexane, tetrahydrofurane, dimethylformamide, dimethylacetamide, and the like. The reaction temperature may vary within a quite wide range without prejudice for the reaction course. The preferred temperature range is comprised between about -10°C and the reflux temperature of the reaction mixture; the reaction is completed in a time period varying from about 2 to about 30 hours. The molar amounts of the reagents of formula II and III are not critical for the good progress of the cyclization, as such reagents can be employed in the widest reciprocal stoichiometric ratios. When 2,3-dihydro-4H-1,3-benzoxazinones or -benzothiazinones wherein R is hydrogen or methyl are desired, precursors of the compound of formula III, such as paraformaldehyde and paraldhyde, are preferably employed. The 2,3-dihydro-1,3-benzoxazine or -benzothiazine derivatives of formula IV wherein R₃ is (C₂₋₄)acyl are then converted into the desired compounds of formula I as shown in the following reaction scheme wherein R, R₁, R₂, X and Y are as defined above and halo is a halogen atom. It is apparent to the skilled in the art that when a compound of formula IV wherein R₃ is hydrogen is obtained by condensing compounds of formulas II and III, it is directly submitted to step ii) of scheme 1 above. Thus, according to step i) of scheme 1, the compounds of formula IV are converted into the compounds of formula V by hydrolysis in an aqueous, alcoholic or aqueous/alcoholic alkaline environment, for example by treatment with an alkaline or alkali-earth metal carbonate or hydrogencarbonate in methanol or ethanol at room temperature for about 10-15 hours. The free OH group of the compounds of formula V is then replaced by a halogen atom by means of common halogenating agents such as, for example, thionyl chloride, sulfuryl chloride, phosphorous trichloride, phosphorous pentachloride, phosphorous oxytrichloride, phosphorous tribromide, sulfuryl bromide and the like. The reaction proceeds in an organic solvent, preferably inert organic solvent again selected from those above employed in the formation of the heterocycle of formula IV, at a temperature varying between about the room temperature and the reflux temperature of the reaction mixture. Thus, compounds of formula VI are obtained, which are subsequently converted into the desired compounds of formula I by procedures suitable for the introduction of the -ONO₂ group, for example by treatment with silver nitrate in the presence of an inert organic solvent such as acetonitrile. Preferably, a molar excess of silver nitrate is used, calculated over the compound of formula VI, and the reaction is carried out at a temperature between the boiling temperature of the reaction mixture and the room temperature. The reaction is completed in a time period ranging from about 2 to about 6 hours. The desired final products of formula I are then recovered according to common techniques. The compounds of the invention possess a cardiovascular activity. In particular they showed marked vasorelaxing properties in vitro and remarkable vasodilating and antianginal activity when tested in the laboratory animals. These favourable biologic properties are combined with a neglegible hypotensive effect, being it known that this is an undesired side-effect of the nitroderivatives known and employed in therapy. Furthermore it was surprisingly found that the vasodilating activity of the present compounds is specific for the coronaric conductive vessels . Thus the compounds of the invention may be considered as drugs endowed with potentially coronodilating and specific antianginal actions. Also, they showed to possess antiarrhythmic activity, and this is a further favourable property because the anginal attacks are often associated with more or less marked arrhythmias. The in vitro vasorelaxing activity was determined by the test of the rabbit aorta strip contracted with noradrenaline. The test was carried out according to the method described by K. Murakami et al., Eur. J. Pharmacol., 141, 195 (1987). The IC₅₀ values ie., the concentrations of active substances causing a 50% inhibition of the contraction of the rabbit aorta strip, were determined. The results obtained with some compounds representative of the invention are set forth in the following Table 1 Compound of Example Vasodilative activity in vitro IC₅₀ Mole/l19.4 x 10⁻⁸ 25.4 x 10⁻⁹ 36.3 x 10⁻⁹ 47.5 x 10⁻⁸ 78.8 x 10⁻⁹ 81.9 x 10⁻⁸ 91.4 x 10⁻⁸ 101.7 x 10⁻⁸ The antianginal activity in vivo was determined on anaesthetized Sprague Dawley rats of weight 350-400 g, operating according to the method of M. Leitold et al., Arzeim. Forsch., 36, 1454, (1986). The test was carried out by intravenously administering the animals with one I.U/Kg, equivalent to 3 mg/Kg of Arg-vasopressin, thus inducing a coronaric spasm that is reproducible and may be electrocardiographically monitored by an increase of the T-wave. The compounds of the invention were administered by gastric gavage at a dose of 3 mg/Kg one hour before the administration of Arg-vasopressin. The antianginal effect was expressed as the percentage inhibition of the increase of the T-wave versus the controls. Another group of animals were intravenously administred with 4 increasing doses of the compound of the invention to measure their ED₅₀, i.e. the dose yielding the 50% inhibition of the increase of the T-wave. The results obtained for some compounds representative of the invention are set forth in Table 2 and Table 3 Example %Inhibition of the increase of the T-wave versus the controls (3mg/Kg per os) 155 331 431 Example ED₅₀ (mg/Kg) (i.v.) 10.0013 20.0063 30.011 40.012 7>0.1 80.058 The above mentioned favourable biological properties are also accompanied by a low toxicity. In fact the LD₅₀ values determined according to the method of Lichtfield and Wilcoxon, J. Pharm. Expt. Ther., 96, 99 (1949) are higher than 500 mg/Kg i.p. in mouse and 800 mg/Kg peros in rat. Object of the present invention is also the use of of the new compounds as antianginal agents, in connection with the industrially applicable acts and aspects of said use, comprising their incorporation into pharmaceutical compositions. Examples of such pharmaceutical compositions are tablets, sugar and film coated tablets, syrups and vials, the latter being suitable both for oral and intramuscular or intravenous administration. They contain the active substance alone or in combination with the usual pharmaceutically acceptable carriers and excipients. The dosages of active substance employed to combat the anginal attacks may vary within wide limits according to the kind of compound used and they are chosen to ensure the most effective therapeutic coverage along the 24 hours. The starting amides of formula II are known substances or may be prepared as shown in the examples hereinbelow reported, from the corresponding salicylates or thiosalicylates of formula wherein R₁, R₂ and X have the above mentioned meanings, and R₄ is a C₁-C₄ alkyl, preferably methyl. In turn the compounds of formula VII are known from the literature or are synthetized according to procedures well known to the skilled artisan, starting from the corresponding salicylic and thiosalicylic acids. The aldehydes of formula III, the derivatives and precursors thereof, are commercial products, or are prepared according to methods known from the literature. The ¹H-NMR spectra were recorded in dimethylsulfoxide (DMSO) with a VARIAN GEMINI 200 spectrometer. The ¹³C-NMR spectra were recorded by using a VARIAN GEMINI 200 spectometer, taking the dimethylsulfoxide (DMSO) 39.5 ppm peak as the reference peak. The invention may be better illustrated by the following examples. PART APreparation of the amides of formula IICompound 1 - N-(2'-Hydroxyethyl)-salicylamideThis compound was prepared as described in Aust. J. Chem., 25, 1797 (1972). Compound 2 - N-(2'-Hydroxyethyl)-5-methyl-salicylamide8.5 g of methyl 5-methyl-salicylate (J. Chem. Soc., 661, 1961) in 3.7 ml of 2-aminoethanol were heated at 170°C for 3 hours. After cooling to room temperature, the reaction mixture was taken up with ethylacetate, washed with 5% hydrochloric acid and dried over sodium sulfate. Yield: 9 g M.p. 73-75°C (n-hexane). Compound 3 - 4-Chloro-N-(2'-hydroxyethyl)-salicylamideThe compound was prepared following the procedure of the previous example starting from 20 g of methyl 4-chlorosalicylate (Chem. Abs. 81, 3624q) and 8 ml of 2-aminoethanol. Yield: 11 g M.p. 95-97°C (chloroform). Compound 4 - N-(2'-Hydroxyethyl)-4-methylsalicylamideThe compound was prepared following the procedure employed for the preparation of Compound 2 starting from 20 g of methyl 4-methylsalicylate (Chem. Abs. 64, 6568d) and 9 ml of 2-aminoethanol. Yield: 16.7 g M.p. 78-80°C (n-hexane). Compound 5 - 5-Chloro-N-(2'-hydroxyethyl)-salicylamideThe compound was prepared following the procedure employed for the preparation of Compound 2 starting from 19 g of methyl 5-chlorosalicylate (Arch. Pharm. 296(10), 714, 1963) and 7.5 ml of 2-aminoethanol. Yield: 13.8 g M.p. 100-102°C (n-hexane). Compound 6 - N-(5'-Hydroxypentyl)salicylamideThe compound was prepared following the procedure employed for the preparation of Compound 2 starting from 17.6 g of salicylic acid methyl ester and 8.5 ml of 5-aminopentanol. Yield: 11 g. The compound is an oil and is used as such in the preparation of the compound of Example 8, PART B. Compound 7 - N-(2'-Hydroxyethyl)-4-methoxysalicylamideThe compound was prepared following the procedure employed for the preparation of Compound 2 starting from 16.9 g of methyl 4-methoxysalicylate (J. Org. Chem., 23, 756, 1958) and 7 ml of 2-aminoethanol. Yield: 9.5 g M.p. 92-94°C (n-hexane). Compound 8 - N-(2-hydroxyethyl)-2-mercaptobenzamideA solution of 5 g (0.03 mole of methyl thiosalicylate (Synthesis, 59, 1974) in 4 ml (0.06 mole) of ethanolamine was heated to 140°C while distilling off the formed methanol. After 2 hours the solution was poured into water and extracted with ethyl acetate. After anhydrification and evaporation under vacuum of the organic layer, 4.2 g (0.01 mole) of bis-[2-(2-hydroxy-ethyl)carboxamidophenyl]disulfide were obtained and as such dissolved in 32 ml of ethanol. The solution was heated to 65°C and dropwise added with 0.4 (0.01 mole) of sodium borohydride in 21 ml of ethanol. The temperature of the solution was maintained at 65°C for 1 hour and then brought to room temperature. The residue obtained by evaporation of the solvent was chromatographed on silica gel by eluting with ethyl acetate. 1.4 g of the title compound were obtained as an oil having the following characteristics: Elemental analysis C% H% N% S% Calculated54.805.627.1016.25 Found54.785.606.9116.19 PART BPreparation of the compounds of formula IExample 12,3-Dihydro-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-oneA) A solution of 18.5 g (0.102 mole) of Compound 1 in 500 ml of chloroform and 11 ml of glacial acetic acid was added with 5.5 g of paraformaldehyde. The mixture was cooled to 0°C and added with 10 g of gaseous hydrochloric acid in 30 minutes, and the resulting solution was stirred at room temperature for 24 hours. The formed oily layer was discarded and the chloroform layer was washed with water and dried over sodium sulfate. The crude residue obtained after evaporation of the solvent was purified by silica gel column chromatography by eluting with methylene chloride/acetone = 85/15 (v/v). 13 g of 3-(2'-acetoxyethyl)-2,3-dihydro-4H-1,3-benzoxazin-4-one were recovered. M.p. 49-51°C (acetone). B) A solution of 13 g (0.055 mole) of the compound prepared under A), in 230 ml of methanol was added with 2.75 g (0.026 mole) of sodium carbonate, and the resulting mixture was left at room temperature for 12 hours. The crude residue obtained after evaporation of the solvent was taken up with methylene chloride and the resulting organic layer was washed with water and dried over sodium sulfate. After evaporation of the methylene chloride, 9.5 g of 2,3-dihydro-3-(2'-hydroxyethyl)-4H-1,3-benzoxazin-4-one were obtained. M.p. 59-61°C (methylene chloride/acetone = 1/9 v/v). C) The product obtained under B) (9 g, 0.046 mole) was dissolved in 70 ml of chloroform, and the resulting solution was added dropwise with 3.54 ml (0.048 mole) of thionyl chloride. The whole was heated at 70°C for 3 hours. After washing with 5% sodium hydrocarbonate and water, drying over sodium sulfate, and subsequent evaporation of the solvent, 9.3 g of 3-(2'-chloroethyl)-2,3-dihydro-4H-1,3-benzoxazin-4-one were obtained. M.p. 45-47°C (n-hexane). D) The product obtained under C) (5.0 g, 0.023 mole) was dissolved in 50 ml of acetonitrile, and the resulting solution was added with 6 g (0.035 mole) of silver nitrate in 35 ml of acetonitrile. The reaction mixture was heated at 85°C for 2 hours and then cooled to room temperature. The formed salts were removed by filtration and the solvent was evaporated off. The crude product obtained was taken up with methylene chloride, the organic layer was washed with water and dried over sodium sulfate. After evaporation of methylene chloride 4.8 g of the title product were obtained. M.p. 49-51°C (n-hexane). The following compounds were prepared substantially according to the procedures of the different steps A―>D shown in Example 1 starting from the convenient salicylamide or thiosalicylamide. Where otherwise indicated, it has to be understood that every compound A is substantially prepared according to procedure A) of Example 1, every compound B substantially according to procedure B) and so on. Example 22,3-Dihydro-6-methyl-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-oneA) 3-(2'-Acetoxyethyl)-2,3-dihydro-6-methyl-4H-1,3-benzoxazin-4-one starting from 8.0 g (0.041 mole) of Compound 2 and 4.0 g of paraformaldehyde. Yield: 6.0 g M.p. 53-55°C (n-hexane). B) 2,3-Dihydro-3-(2'hydroxyethyl)-6-methyl-4H-1,3-benzoxazin-4-one from 6.0 g (0.024 mole) of the previous compound. Yield: 4.2 g M.p. 59-61°C (diethyl ether). C) 3-(2'-Chloroethyl)-2,3-dihydro-6-methyl-4H-1,3-benzoxazin-4-one from 3.6 g (0.017 mole) of the previous compound. Yield: 3.5 g M.p. 86-88°C (n-hexane). D) 2.7 g of the title compound were obtained starting from 3.3 g (0.014 mole) of the previous compound. M.p. 76-78°C (diethyl ether/n-hexane = 1/9 v/v). Example 3 7-Chloro-2,3-dihydro-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-one A) 3-(2'-Acetoxyethyl)-7-chloro-2,3-dihydro-4H-1,3-benzoxazin-4-one from 11 g (0.051 mole) of Compound 3 and 4.5 g of paraformaldehyde. Yield: 9 g M.p. 92-94°C (n-hexane). B) 7-Chloro-2,3-dihydro-3-(2'-hydroxyethyl)-4H-1,3-benzoxazin- 4-one from 8 g (0.030 mole) of the previous compound. Yield: 6.1 g M.p. 104-106°C (n-hexane). C) 7-Chloro-3-(2'-chloroethyl)-2,3-dihydro-4H-1,3-benzoxazin-4-one from 8 g (0.035 mole) of the previous compound. Yield: 6.2 g M.p. 103-105°C (diethyl ether). D) 5.8 g of the title compound were obtained starting from 6 g (0.024 mole) of the previous compound. M.p. 86-88°C (n-hexane). Example 42,3-Dihydro-7-methyl-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-oneA) 3-(2'-Acetoxyethyl)-7-methyl-2,3-dihydro-4H-1,3-benzoxazin-4-one from 16 g (0.081 mole) of Compound 4 and 4.5 g of paraformaldehyde. Yield 13 g of oil showing the following characteristics: Elemental analysis: C% H% N% Calculated62.646.075.62 Found62.276.035.58 ¹H-NMR - characteristic resonance peaks are observed at the following δ (ppm): 7.59 (d, 1H); 6.98 (d, 1H); 6.91 (s, 1H); 5.19 (s, 2H); 4.18 (t, 2H); 3.68 (t, 2H); 2.01 (s, 3H) ¹³C-NMR - characteristic resonance peaks are observed at the following δ (ppm): 171.86; 161.73; 156.03; 145.93; 127.61; 123.04; 116.98; 115.55; 79.04; 68.45; 45.28; 18.41 B) 2,3-Dihydro-3-(2'-hydroxyethyl)-7-methyl-4H-1,3-benzoxazin-4-one from 12 g of the previous compound. Yield: 9 g of product as an oil, used as such in the next step. C) 3-(2'-Chloroethyl)-2,3-dihydro-7-methyl-4H-1,3-benzoxazin-4-one from 4 g of the previous compound. Yield: 3.7 g M.p. 82-84°C (n-hexane). D) 2.5 g of the title product were obtained from 3 g (0.013 mole) of the previous compound. M.p. 89-91°C (ethyl acetate/n-hexane = 1/9 v/v). Example 52,3-Dihydro-2-methyl-3-(2'nitrooxyethyl)-4H-1,3-benzoxazin-4-oneA) 3-(2'-Acetoxyethyl)-2-methyl-2,3-dihydro-4H-1,3-benzoxazin-4-one starting from 18.4 g (0.101 mole) of Compound 1 and 8.13 ml (0.061 mole) of paraldehyde. Yield: 6.7 g of an oil having the following characteristics: Elemental analysis: C% H% N% Calculated62.646.075.62 Found62.356.015.47 ¹H-NMR - characteristic resonance peaks are observed at the following δ (ppm): 7.74 (dd, 1H); 7.52 (dt, 1H); 7.17 (t, 1H); 7.02 (d, 1H); 5.70 (q, 1H); 4.22 (t, 2H); 4.63÷3.83 (m, 1H);3.56÷3.23 (m, 1H); 2.05 (s, 3H); 1.56 (d, 3H) ¹³C-NMR - characteristic resonance peaks are observed at the following δ (ppm): 172.04; 161.58; 156.82; 134.68; 127.82; 122.45; 118.02; 116.93; 84.26; 68.10; 45.63; 22.34; 18.22 B) 2,3-Dihydro-3-(2'-hydroxyethyl)-2-methyl-4H-1,3-benzoxazin-4-one from 6 g (0.029 mole) of the previous compound. Yield: 3.8 g of an oily product used as such in the next step. C) 3-(2'-Chloroethyl)-2,3-dihydro-2-methyl-4H-1,3-benzoxazin-4-one from 3.5 g of the previous compound. Yield: 3.1 g of an oily product used as such in the next step. D) 2.1 g of title product were obtained starting from 2.5 g of the previous compound. The product is an oil having the following characteristics: Elemental analysis %C %H %N Calculated52.384.8011.11 Found52.074.7511.03 ¹H-NMR - characteristic resonance peaks are observed at the following δ(ppm) 7.77 (dd, 1H); 7.52 (dt, 1H); 7.12 (t, 1H); 7.02 (d, 1H); 5.72 (q, 1H); 4.70 (t, 2H); 4.12÷3.97 (m, 1H); 3.66÷3.51 (m, 1H); 1.49 (d, 3H) ¹³C-NMR - characteristic resonance peaks are observed at the following δ (ppm) 161.72; 156.83; 134.65; 128.09; 122.77; 118.71; 116.69; 83.68; 71.72; 40.08; 20.6 Example 62,3-Dihydro-2,7-dimethyl-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-oneA) 3-(2'Acetoxyethyl)-2,7-dimethyl-2,3-dihydro-4H-1,3-benzoxazin-4-one from 6 g (0.030 mole) of Compound 4 and 2.4 ml (0.018 mole) of paraldehyde. 2.5 g of product were obtained as an oil having the following characteristics: Elemental analysis %C %H %N Calculated63.876.515.32 Found63.716.485.27 ¹H-NMR - characteristic resonance peaks are observed at the following δ(ppm) 7.63 (d, 1H); 6.92 (d, 1H); 6.88 (s, 1H); 5.66 (q, 1H); 4.28 (t, 2H); 4.08÷3.78 (m, 1H); 3.52÷3.22 (m, 1H); 2.35 (s, 3H); 2.02 (s, 3H); 1.52 (s, 3H) ¹³C-NMR - characteristic resonance peaks are observed at the following δ(ppm): 171.79; 161.35; 144.81; 127.75; 124.08; 117.88; 115.57; 84.33; 67.96; 44.82; 21.75; 18.66; 18.14 B) 2,3-Dihydro-3-(2'-hydroxyethyl)-2,7-dimethyl-4H-1,3-benzoxazin-4-one from 2.3 g (0.009 mole) of the previous compound. Yield: 2.1 g of an oil used as such in the next step. C) 3-(2'-Chloroethyl)-2,3-dihydro-2,7-dimethyl-4H-1,3-benzoxazin-4-one from 3.4 g of the previous compound. Yield: 3.2 g of an oil used as such in the next step. D) 1.1 g of the title product were obtained starting from 3.1 g of the previous compound. The product is an oil having the following characteristics: Elemental analysis C% H% N% Calculated54.135.3010.52 Found53.975.2510.43 ¹H-NMR - characteristic resonance peaks are observed at the following δ(ppm) 7.67 (d, 1H); 6.95 (d, 1H); 6.86 (s, 1H); 5.70 (q, 1H); 4.72 (t, 2H); 4.11÷3.98 (m, 1H); 3.64÷3.52 (m, 1H); 2.33 (s, 3H); 1.49 (d, 3H) ¹³C-NMR - characteristic resonance peaks are observed at the following δ(ppm) 161.32; 155.73; 145.70; 127.66; 123.52; 117.28; 115.36; 84.77; 71.47; 40.01;21.23; 18.59 Example 76-Chloro-2,3-dihydro-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-oneA) 3-(2'-Acetoxyethyl)-6-chloro-2,3-dihydro-4H-1,3-benzoxazin-4-one from 13 g (0.060 mole) of Compound 5 and 4.5 g of paraformaldehyde. Yield: 11 g M.p. 93-95°C (n-hexane). B) 6-Chloro-2,3-dihydro-3-(2'-hydroxyethyl)-4H-1,3-benzoxazin-4-one from 10 g (0.037 mole) of the previous compound. Yield: 7 g M.p. 88-90°C (diethyl ether). C) 6-Chloro-3-(2'-chloroethyl)-2,3-dihydro-4H-1,3-benzoxazin-4-one from 8.5 g (0.037 mole) of the previous compound. Yield: 6.5 g M.p. 75-77°C (diethyl ether). D) 3.7 of the title product were obtained starting from 4 g (0.016 mole) of the previous compound. M.p. 98-100°C (n-hexane). Example 82,3-Dihydro-3-(5'-nitrooxypentyl)-4H-1,3-benzoxazin-4-oneA) N-(5'-Acetoxypentyl)-2,3-dihydro-4H-1,3-benzoxazin-4-one from 11.4 g (0.051 mole) of Compound 6 and 4.5 g of paraformaldehyde. Yield:9 g of product as an oil having the following characteristic: Elemental analysis C% H% N% Calculated64.976.915.05 Found64.666.885.01 ¹H-NMR - characteristic resonance peaks are observed at the following δ(ppm) 7.79 (dd, 1H); 7.51 (dt, 1H); 7.14 (t, 1H); 7.04 (d, 1H); 5.29 (s, 2H); 4.03 (t, 2H); 3.44 (t, 2H); 2.04 (s, 3H); 1.60÷1.19 (m, 6H) ¹³C-NMR - characteristic resonance peaks are observed at the following δ8ppm) 171.43; 162.04; 156.23; 134.35; 127.92; 123.01; 118.78; 116.32; 78.12; 68.03; 44.27; 29.72; 28.97; 23.84; 18.13 B) 2,3-Dihydro-3-(5'-hydroxypentyl)-4H-1,3-benzoxazin-4-one from 8.5 g (0.031 mole) of the previous compound. 5.3 g of product as an oil were obtained used as such in the next step. C) 3-(5'-Chloropentyl)-2,3-dihydro-4H-1,3-benzoxazin-4-one- from 7.3 g of the previous compound. Yield: 4.6 g M.p. 41-43°C (n-hexane). D) 2.5 g of the title product were obtained starting from 8 g (0.031 mole) of the previous compound. M.p. 39-41°C (n-hexane). Example 92,3-Dihydro-7-methoxy-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-oneA) 3-(2'-hydroxyethyl)-7-methoxy-2,3-dihydro-4H-1,3-benzoxazin-4-one, 9 g (0.042 mole) of Compound 7 and 0.81 g (0.004 mole) of p-toluensulfonic acid were dissolved in 130 ml of benzene, and 4 Å molecular sieves and 1.55 g of paraformaldehyde were added to the resulting solution. The mixture was refluxed for 2 hours and, after cooling to room temperature, added with 300 ml of ethyl acetate. The molecular sieves were removed by filtration, the solution was washed with water, the organic layer was recovered and dried over sodium sulfate. After evaporation of the solvent, 10.3 g of a residue were obtained which was purified through a silica gel column by eluting with ethyl acetate/n-hexane = 8/2 (v/v). Yield: 2.1 g of product as an oil having the following characteristics: Elemental analysis C% H% N% Calculated59.195.876.27 Found59.015.846.21 ¹H-NMR - characteristic resonance peaks are observed at the following δ(ppm) 7.83 (d, 1H); 6.63 (dd, 1H); 6.42 (d, 1H); 5.36 (s, 2H); 4.88 (t, 1H); 3.62÷3.47 (m, 4H); 3.81 (s, 3H) ¹³C-NMR - characteristic resonance peaks are observed at the following δ(ppm) 163.18; 157.36; 154.28; 132.48; 130.76; 115.13; 109.78; 77.39; 59.42; 47.19 C) 3-(2'-Chloroethyl)-2,3-dihydro-7-methoxy-4H-1,3-benzoxazin-4-one from 2g (0.009 mole) of the previous compound. Yield: 1.9 g of product as oil used as such in the next step. D) 1.7 of the title product were obtained starting from 2 g (0.008 mole) of the previous compound. M.p. 97-99°C (n-hexane). Example 103-(2'-nitrooxyethyl)-2,3-dihydro-4H-1,3-benzothiazin-4-oneA-B) 3-(2'-hydroxyethyl)-2,3-dihydro-4H-1,3-benzothiazin-4-one A solution of 3.5 g (0.017 mole) of the compound 8 in 50 ml of dioxane was added with 1.59 g (0.053 mole) of paraformaldehyde. The solution cooled to 0°C was saturated with gaseous hydrochloric acid, then brought to room temperature and stirred for 3 days. After dilution with water the reaction mixture was extracted with ethyl acetate. The organic phase was dried over sodium sulfate and evaporated under vacuum and the obtained residue was chromatographed through silica gel (ethyl acetate/hexane 8/2 (v/v) as the eluent). 1.5 g of the title compound was obtained as an oil which was used as such in the subsequent step. C) 3-(2'-chloroethyl)-2,3-dihydro-4H-1,3-benzothiazin-4-one. The compound was prepared as described in Example 1C) starting from 1 g (0.0048 mole) of the product obtained under B). 0.980 g of the title compound were obtained as an oil which was used as such in the subsequent step. D) 3-(2'-nitrooxyethyl)-2,3-dihydro-4H-1,3-benzothiazin-4-one The compound was prepared as described in Example 1D) starting from 0.700 g (0.003 mole) of the product obtained under C). 0.530 g of the title product were obtained. M.p. 68-69°C Elemental Analysis C% H% N% S% Calculated47.243.9611.0212.61 Found47.213.9311.0512.57 ¹H-NMR in DMSO 7.96 (dd, 1H); 7.52÷7.29 (m, 3H); 4.88 (s, 2H); 4.76 (t, 2H); 3.94 (t, 2H) The following products of general formula I were prepared according to the methods decribed in the previous examples starting from the convenient amide and carbonyl compounds, derivatives or precursors thereof. | Claims for the following Contracting States : AT, BE, CH, DE, DK, FR, GB, IT, LI, LU, NL, SECompounds of general formula wherein R represents hydrogen, (C₁₋₆)alkyl, cyclopentyl, cyclohexyl, cycloheptyl, phenyl optionally substituted with 1 or 2 groups independently selected from hydroxy, halogen, nitro, (C₁₋₄)alkyl and (C₁₋₄)alkoxy, methylenedioxyphenyl; R₁ and R₂ independently represent hydrogen, halogen, (C₁₋₄)alkyl, (C₁₋₄)alkoxy or trifluoromethyl; X is an oxygen or a sulfur atom, Y represents a (C₂-C₆)alkylene chain or a cyclopentylene, cyclohexylene or cycloheptylene group; and the pharmaceutically acceptable acid salts thereof. Compounds according to claim 1 wherein R is hydrogen, (C₁₋₄)alkyl, cyclopentyl, cyclohexyl or cycloheptyl; R₁ and R₂ independently represent hydrogen, halogen, (C₁₋₄)alkyl or (C₁₋₄)alkoxy; X is an oxygen or a sulfur atom and Y represents a (C₂₋₆)alkylene chain or a cyclopentylene, cyclohexylene or cycloheptylene moiety; and the pharmaceutically acceptable salts thereof. Compounds according to claims 1 and 2 wherein R is hydrogen, R₁ and R₂ independently represent hydrogen, halogen, (C₁₋₄)alkyl or (C₁₋₄)alkoxy; X is an oxygen or a sulfur atom; and Y is a (C₂₋₆)alkylene chain; and the pharmaceutically acceptable salts thereof. A compound as defined in claim 1 which is 2,3-dihydro-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-one. A compound as defined in claim 1 which is 2,3-dihydro-6-methyl-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-one. A compound as defined in claim 1 which is 2,3-dihydro-7-chloro-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-one. A compound as defined in claim 1 which is 2,3-dihydro-7-methyl-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-one. A compound as defined in claim 1 which is 2,3-dihydro-3-(2'-nitrooxyethyl)-4H-1,3-benzothiazin-4-one. A pharmaceutical composition useful in the cardiovascular therapy, comprising a therapeutically effective amount of at least one of the compounds as defined in claim 1 together with at least a pharmaceutically acceptable excipient. Use of a compound according to claim 1 for the manufacture of a medicament useful in the cardiovascular therapy. A process for preparing the compounds of formula I wherein R, R₁, R₂, X and Y are as in claim 1, characterized in that an amide of formula II is condensed with an aldehyde of formula IIIR-CHO III or a derivative or precursor thereof, in an acidic medium comprising a strong mineral acid and a (C₂-C₄)alkanoic acid or in molecular sieves in the presence of sulfonic acids, in an organic solvent, thereby obtaining a compound of formula IV wherein R₃ is a (C₂₋₄)acyl group or hydrogen, which, when R₃ is (C₂₋₄)acyl, is converted into the corresponding compound of formula V by hydrolysis; said process being further characterized in that the compound of formula IV wherein R₃ is hydrogen or the compound of formula V is reacted with a halogenating agent to obtain a compound of formula VI wherein halo is a halogen atom, which is converted into the final compound of formula I by treatment with a nitrating agent such as silver nitrate in the presence of an organic solvent at a temperature between the reflux temperature of the reaction mixture and the room temperature. Claims for the following Contracting States : ES, GRProcess for producing compounds of general formula wherein R represents hydrogen, (C₁₋₆)alkyl, cyclopentyl, cyclohexyl, cycloheptyl, phenyl optionally substituted with 1 or 2 groups independently selected from hydroxy, halogen, nitro, (C₁₋₄)alkyl and (C₁₋₄)alkoxy, methylenedioxyphenyl; R₁ and R₂ independently represent hydrogen, halogen, (C₁₋₄)alkyl, (C₁₋₄)alkoxy or trifluoromethyl; X is an oxygen or a sulfur atom, Y represents a (C₂-C₆)alkylene chain or a cyclopentylene, cyclo hexylene or cycloheptylene group; and the pharmaceutically acceptable acid salts thereof, characterized in that an amide of formula II is condensed with an aldehyde of formula IIIR-CHO III or a derivative or precursor thereof, in an acidic medium comprising a strong mineral acid and a (C₂-C₄)alkanoic acid or in molecular sieves in the presence of sulfonic acids, in an organic solvent, thereby obtaining a compound of formula IV wherein R₃ is a (C₂₋₄)acyl group or hydrogen, which, when R₃ is (C₂₋₄)acyl, is converted into the corresponding compound of formula V by hydrolysis; said process being further characterized in that the compound of formula IV wherein R₃ is hydrogen or the compound of formula V is reacted with a halogenating agent to obtain a compound of formula VI wherein halo is a halogen atom, which is converted into the final compound of formula I by treatment with a nitrating agent such as silver nitrate in the presence of an organic solvent at a temperature between the reflux temperature of the reaction mixture and the room temperature. Process according to claim 1 wherein in the formula I R is hydrogen, (C₁₋₄)alkyl, cyclopentyl, cyclohexyl or cycloheptyl; R₁ and R₂ independently represent hydrogen, halogen, (C₁₋₄)alkyl or (C₁₋₄)alkoxy; X is an oxygen or a sulfur atom and Y represents a (C₂₋₆)alkylene chain or a cyclopentylene, cyclohexylene or cycloheptylene moiety; and the pharmaceutically acceptable salts thereof. Process according to claims 1 and 2 wherein in the formula I R is hydrogen, R₁ and R₂ independently represent hydrogen, halogen, (C₁₋₄)alkyl or (C₁₋₄)alkoxy; X is an oxygen or a sulfur atom; and Y is a (C₂₋₆)alkylene chain; and the pharmaceutically acceptable salts thereof. Process according to claim 1 wherein the compound of formula I is 2,3-dihydro-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-one. Process according to claim 1 wherein the compound of formula I is 2,3-dihydro-6-methyl-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-one. Process according to claim 1 wherein the compound of formula I is 2,3-dihydro-7-chloro-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-one. Process according to claim 1 wherein the compound or formula I is 2,3-dihydro-7-methyl-3-(2'-nitrooxyethyl)-4H-1,3-benzoxazin-4-one. Process according to claim 1 wherein the compound of formula I is 2,3-dihydro-3-(2'-nitrooxyethyl)-4H-1,3-benzothiazin-4-one. | ITALFARMACO SPA; ITALFARMACO S.P.A. | BENEDINI FRANCESCA; CEREDA ROBERTA; DEL SOLDATO PIERO; SALA ALBERTO; BENEDINI, FRANCESCA; CEREDA, ROBERTA; DEL SOLDATO, PIERO; SALA, ALBERTO |
EP-0490185-B1 | 490,185 | EP | B1 | EN | 19,950,201 | 1,992 | 20,100,220 | new | B66C9 | null | B66C9 | B66C 9/16 | Inverter bridge unit and a procedure for its use | The invention relates to a three-phase inverter bridge unit, containing for each phase a branch consisting of gate-controlled solid-state switches (T1'-T6'), said switches being used to convert a d.c. voltage into a three-phase a.c. voltage feeding a three-phase load (3'), and a control unit (5') for controlling the solid-state switches, and to a procedure for the use of the inverter bridge unit to prevent skewing of a lifting apparatus. The bridge unit comprises a parallel branch consisting of controlled solid-state switches (T7',T8') and connected in parallel with one of the branches of the bridge, said parallel branch being used along with the other phase branches feeding said three-phase load to feed another three-phase load (4'). | The present invention relates to an inverter bridge unit as defined in the introductory part of claim 1, and to its use. In cranes, skewing occurs in consequence of differences between the rotational speeds of the traversing motors of the crane, said differences being determined by the load moments of different motors, motor-specific slip relations and differences in feed cable impedances. Skewing may also result from differences in the degree of wear or friction of the bearing wheels of the crane, from dirt accumulated on load-bearing surfaces, from slipping during braking, etc. At present, correction of the skewing of cranes is effected by using separate frequency converters in which each inverter bridge feeds a different traversing motor. In a previously known solution, skewing is corrected as illustrated by Fig. 1 by using a control unit which performs the required measurements, comparison of results and the control functions required by each inverter bridge. It is also possible to make the steel structures of the crane rigid enough to prevent skewing. This is sometimes the principle observed in mechanical design. The drawbacks of previously known solutions include the following: To achieve the structural rigidity required in each case, it is necessary to use either oversized crane structures or special designs instead of standard solutions. Since no economic and reliable method to prevent skewing exists, crane designers may end up with more complex mechanical constructions than required by the basic function of the crane. An increased use of remote control (in the case of both new cranes and modernisations) imposes additional demands on the prevention of skewing, because the immediate (local) supervision and control by the crane operator is either missing or insufficient. In this case, a fast and automatic procedure for the prevention of skewing is required. In most cases, automatization is based on a predetermined positioning accuracy, which may be a decisive factor contributing to the costs of automatization. In addition to the prevention of the mechanical drawbacks resulting from skewing, these applications generally require precisely timed equalization between the ends of the crane to achieve a sufficient load positioning accuracy. The object of the present invention is to eliminate the drawbacks of the previously known solutions. According to the invention, the rotational speeds of motors (or motor groups) fed by inverter bridges can be adjusted or corrected independently of each other by adding in the power stage of the inverter bridge a parallel branch to the switching component pair feeding one of the phases. Thus, in the three-phase system feeding each motor, two of the phases are identically arranged while the voltage of the third phase can be adjusted separately. The invention provides the following advantages as compared to previously known techniques: its inverter bridge solution and its control system are compact, the number of solid state components used in it is smaller and their control simpler than in previously known solutions. In the following, the invention is described in detail by the aid of an example by referring to the attached drawings, in which Fig. 1 presents a solution based on previously known techniques, implemented using separate inverter bridges; Fig. 2 presents the solution of the invention, implemented using a single inverter bridge; Fig. 3 illustrates the measurement of skewing; Fig. 4 illustrates another skewing measurement application. Fig. 1 presents a previously known arrangement for the correction of crane skewing using inverters. It comprises two squirrel-cage motors 3 (M1) and 4 (M2), each of which drives its own traversing mechanism. Each motor is fed by an inverter producing a symmetrical three-phase supply, motor 3 (M1) being fed by inverter 1 and motor 2 (M2) by inverter 2. Inverter 1 is controlled by control unit 9 and inverter 2 by control unit 10. The circuits producing the d.c. voltage feeding the inverters are not shown in Fig. 1, and neither is the normal inverter control system. The position of the crane part driven by each traversing mechanism is measured by a position measurement unit 6, 7. The information provided by each of these units is compared with that of the other in a comparison/correction unit 8, which issues a skewing correction command to control unit 9 and/or 10, which control the transistors T1-T6 and T7-T12 of the bridges. The deviation resulting from skewing can also be measured in only one crane part, in which case no comparison is needed and the skewing can be corrected by controlling only one of the inverters. In the solution of the invention presented in Fig. 2, a single three-phase inverter bridge 1' is used to feed both motors 3' and 4'. The bridge comprises transistors T1'-T6' like bridge 1 feeding motor 3 in Fig.1. Moreover, an additional branch consisting of transistors T7' and T8' has been connected in parallel with transistor pair T3',T6'. Thus, in two phases of the bridge the same branch and therefore the same transistors T1', T2', T4' and T5' are connected to both motors. In one phase, the transistors T3' and T6' of the first branch are connected to the first motor 3' while the transistors T7'and T8' of the second branch, which is parallel with the first branch, are connected to the second motor 4. In Fig. 2, the position of the crane or its part is measured by position measurement units 6' and 7', whose outputs are compared in a comparison/correction unit 8', which issues a skewing correction instruction to the control unit 9', which controls the solid state switches of the bridge 1' as provided by the invention. The difference with regard to previously known techniques is that the number of solid state switches in the bridge 1' is smaller than the total number of solid state switches in the bridges 1 and 2 in the previously known solution in Fig. 1. A further difference is that the bridge in the solution of the present invention requires only one control unit 9' whereas the previously known solution in Fig. 1 for the correction of skewing uses two control units 9 and 10. The control of the bridge 1' can be implemented using separate adjustment to produce e.g. an asymmetric stator voltage limitation by reducing the voltage in one of the phases, in which case the rotational speed can be adjusted independently although the basic frequency remains the same. In this case, the adjustment of rotational speed is based on a reduction of the top moment and a flatter gradient of the moment curve of the motor. Fig. 3 illustrates the measurement of skewing. The crane structure consists of an essentially rigid main carrier 11 and crane heads 12a and 12b. The crane moves on a pair of essentially parallel rails 13a and 13b. The crane is presented in a skew position, i.e. the whole crane has turned horizontally through a small angle relative to the rails. The lifting machinery of the crane is not shown. The skewing of the crane is detected by measuring the position of head 12a or 12b relative to rail 13a or 13b or to some other fixed structure by means of approach detectors or approach switches 14. The correction of skewing can be performed in the manner explained in the description of Fig. 2, e.g. by limiting the voltage fed to the traversing motor(s) driving the leading crane head until the skewing has been corrected, i.e. until the heads 12a and 12b are in a parallel position relative to the rails 13a and 13b. Fig. 4 illustrates another principle of crane skewing measurement. In this case, the crane cannot turn horizontally as in Fig. 3. The crane heads 15a and 15b remain oriented essentially in the direction of the rails 13a and 13b, but the crane structures themselves now undergo deflections or changes of position due to skewing. One or both of the crane heads 15a and 15b may be pivoted on the main support 16, and the difference between the positions of the main support 16 and the heads 15a and 15b is measured by means of displacement detectors 17a and 17b. Of course, this difference can also be measured by means of a rotation detector mounted in the joint between the main support and the head. Skewing may also produce a state of strain in the crane structures, and this can be detected by means of suitable detectors mounted on the steel structure to measure the level of strain in the structure. The detectors may be mounted on the main support 16, or they may be attached to the supporting parts of the crane head or to a separate measuring rod placed in a position corresponding to that of the above-mentioned displacement detectors 17a and 17b. The correction of skewing in the case of Fig. 4 is performed in the same way as in Fig. 3. The cranes in Fig. 3 or Fig. 4 may be of various types as to their construction, e.g. semi-gantry or gantry cranes with e.g. A-gantry heads. It is obvious to a person skilled in the art that different embodiments of the invention are not restricted to the examples described above, but that they may instead be varied within the scope of the following claims. | Three-phase inverter bridge unit, containing for each phase a branch consisting of gate-controlled solid-state switches (T1'-T6'), said switches being used to convert a d.c. voltage into a three-phase a.c. voltage feeding a three-phase load (3'), and a control unit (5') for controlling the solid-state switches, characterized in that the bridge unit comprises at least one additional parallel branch consisting of controlled solid-state switches (T7', T8') and connected in parallel with one of the branches of the bridge, said parallel branch being used along with the other phase branches feeding said three-phase load to feed another three-phase load (4'). Inverter bridge unit according to claim 1, characterized in that the loads are asynchronous motors and that the control unit is used to control the rotational speeds of the motors independently of each other, the motors being connected to parallel branches of the bridge. Inverter bridge unit according to claim 1 or 2, characterized in that the control unit adjusts the rotational speed by means of an asymmetric stator voltage limitation involving reduction of the parallel branch voltage. Inverter bridge unit according to claim 1 or 2, characterized in that the control unit adjusts the rotational speed by means of single-phase braking, whereby two of the phases of the motor under adjustment are supplied with equal voltages. Use of the inverter bridge unit as defined in any preceding claim for the prevention of skewing of a lifting apparatus, where the three-phase inverter bridge unit contains for each phase a branch consisting of gate-controlled solid-state switches (T1'-T6') converting a d.c. voltage into a three-phase a.c. voltage feeding a three-phase asynchronous motor (3') or motor group belonging to a first traversing mechanism of the lifting apparatus, and a control unit (5') for controlling the solid-state switches, characterized in that the inverter bridge unit is provided with at least one additional parallel branch consisting of controlled solid-state switches (T7',T8') and connected in parallel with one of the branches of the bridge, said parallel branch being used along with the other phase branches feeding the first three-phase asynchronous motor to feed another three-phase asynchronous motor (4') or motor group serving as a traversing mechanism of the lifting apparatus, and that, to prevent skewing of the lifting apparatus, the rotational speeds of the motors are adjusted by controlling the solid-state switches of the bridge unit on the basis of measurement data obtained from units (6',7') measuring the position of the lifting apparatus or its parts. Use according to claim 5, characterized in that skewing of the lifting apparatus is detected by measuring the position of the lifting apparatus relative to a fixed structure by means of position detectors (6',7'). Use according to claim 5 or 6, characterized in that skewing of the lifting apparatus is detected by means of displacement detectors (17a, 17b) measuring the change in the mutual positions of two parts of the lifting apparatus movable relative to each other, e.g. the main support and a head of the crane. Use according to claim 5,6, or 7, characterized in that skewing of the lifting apparatus is detected by means of detectors (18) measuring the level of strain in a steel structure of the lifting apparatus, said detectors being placed directly on said steel structure or on a measuring rod attached to it. | KCI KONE CRANES INT OY; KCI-KONE CRANES INTERNATIONAL OY | SEITSONEN JUHA; SEITSONEN, JUHA |
EP-0490186-B1 | 490,186 | EP | B1 | EN | 19,950,614 | 1,992 | 20,100,220 | new | H01L23 | H01L21 | G01R31, H01L21 | H01L 21/66M2, T01L21:66M2 | Pattern shift measuring method | A method of measuring pattern shift of a semiconductor wafer (2) with a high accuracy in a short period of time is disclosed, wherein a pattern (4) composed of a groove or a ridge is formed on the semiconductor wafer (2), then at least one oxide film layer (6) extending over and across the pattern is formed, subsequently, after an epitaxial growing process is performed to form an epitaxial layer (8) over the semiconductor wafer (2), the lateral position of the pattern (4) is measured both on the epitaxial layer (8) and on the oxide film layer (6), and after that the position of the pattern (4) measured at the epitaxial layer (8) is compared with the lateral position of the pattern (4) measured at the oxide film layer (6), thereby determining a displacement of the pattern (4). | The present invention relates to a method of measuring the pattern shift occurring in epitaxial growth on a semi-conductor wafer with patterns thereon and more particularly to a method of measuring the pattern shift with a high accuracy in a short period of time. It is essential to control the shift of a buried diffusion pattern after the growth of an epitaxial layer in a bipolar transistor in an IC. For this purpose, the growth conditions (such as reaction temperature and reaction speed) should be always controlled to assure constant pattern shift. However, it is very difficult to control the growth conditions strictly enough to meet the requirements because frequent measurement of the pattern shift is inevitable. Conventionally, the angular lapping and stain method is used for this purpose. This method comprises: (1) slicing chips as samples having a buried layer in parallel to and perpendicular to the orientation flat by using a dicing saw; (2) angular polishing of the new narrow surfaces created as sections of the sliced chips; (3) etching the polished surfaces (Sirt1, 2 to 3 seconds); and (4) measuring the shift of the patterns of the buried layers by using a differential, interference microscope. The pattern shift factor is obtained by the following equation: the pattern shift factor = the amount of shift (µm)/the thickness of the epitaxial layer (µm) However, since it takes more than three hours to measure the pattern shift, this conventional method cannot be used so frequently and is rather expensive. In JP-A-63 029 943 a method is described in which the epitaxial layer is grown only on a part of the wafer surface. The distance between pattern elements on both sides of an epitaxial layer boundary is then compared with the distance between pattern elements on the uncovered part of the wafer. With the foregoing drawbacks of the prior art in view, it is an object of this invention to provide a method which is capable of measuring the pattern shift of a semi-conductor wafer in a short period of time with utmost ease, with a high accuracy and at a low cost. According to this invention, there is provided a method of measuring pattern shift of a semiconductor wafer which is depicted with linear steps thereon: forming a pattern composed of a groove or a ridge on the semiconductor wafer; forming at least one strip of oxide film layer extending over and across the pattern; thereafter, performing an epitaxial growing process to form an epitaxial layer over the semiconductor wafer; measuring the position of the pattern both on the surface of the epitaxial layer and on the oxide film layer; and comparing a measurement of the lateral position of the pattern on the epitaxial layer with a measurement of the lateral position of the pattern on the oxide film layer in the direction perpendicular to the patterns so as to determine a displacement of the stepped pattern. Preferably, the number of the oxide film layer strips is plural, and the pattern and the plural oxide film layer strips jointly form a lattice-like pattern. The displacement of the pattern, namely the pattern shift PS is determined according to the following equation: PS = {(L+R)/2} /T where L is the displacement of the pattern measured at one edge thereof, R is the displacement of the pattern measured at an opposite edge thereof, and T is the thickness of the epitaxial layer. Many other objects, advantages and features of the present invention will be better understood from the following description taken in conjunction with the accompanying drawing. Figure 1 is a diagrammatical view illustrative of the principle of a method of this invention for measuring the pattern shift of an epitaxial layer on a semiconductor wafer. A method of this invention for measuring pattern shift on a semiconductor wafer will be described below in greater detail with reference to the accompanying drawing. Figure 1 diagrammatically shows the principle of the pattern shift measuring method of this invention. In Figure 1, numeral 2 is a semiconductor wafer having a buried diffusion layer of antimony (Sb) which is formed with a pattern 4 delineated as a groove or a ridge. After an oxide film of the semiconductor wafer 2 (hereinafter referred to as buried diffusion wafer ) is removed by hydrofluoric acid, the buried diffusion wafer 2 is oxidized so as to form an oxide film having a thickness not less than 200nm. The oxide film thus formed is selectively removed by photolithography using a desired mask pattern in such a manner that one strip or more of masking oxide film layers 6 (only one strip shown in Figure 1) are formed over and across the pattern 4. Preferably, the strips of the oxide film layers 6 and the pattern 4 cross at right angles to one another so as to form a lattice-like pattern. The oxide film layers 6 preferably have a width in the range of from 50 to 200 µm. An excessively wide oxide film layer brings about undesirable growth of polysilicon. The buried diffusion wafer 2 partly covered with the masking oxide film layers 6 is then subjected to an epitaxial growing process so as to form an epitaxial layer only on the buried diffusion wafer 2. The pattern used herein is advantageous for a subsequent measurement of pattern shift because the masking oxide film layers are in tight contact with a surface of the semiconductor wafer and hence deposition of silicon comes out up to side edges of the masking oxide film layers. The epitaxial growth does not appear at a portion of the buried diffusion wafer (semiconductor wafer) 2 which is covered with the masking oxide film layers 6. The epitaxial growth appears at a portion of the buried diffusion wafer (semiconductor wafer) 2 devoid of the masking oxide film layers 6. With the epitaxial growing process of this nature, an epitaxial layer 8 shown in FIG. 1 is formed. As shown in Figure 1, the epitaxial layer 8 includes a portion 8a overlying the Sb-diffusion layer and a portion 8b overlying a layer free from Sb diffusion (non-Sb-diffusion layer). The Sb-diffusion layer portion 8a represents a pattern which is displaced or shifted in lateral position relative to the original pattern 4 on the buried diffusion wafer. Likewise, the masking oxide film layer 6 includes an Sb-diffusion layer portion 6a (stated in other words, a portion of the pattern 4 which is free from displacement or shift) and a non-Sb-diffusion layer portion 6b. Reference characters L₁, L₂ and R₁, R₂ denote left and right boundaries between the diffusion layer and the non-diffusion area. Reference character C denotes a crown formed in the epitaxial deposition process at a boundary portion between the oxide film layer and the silicon substrate. The crown C is formed in a region extending along the oxide film layer 6 and having a width of from 300 to 400µm, so that an accurate measurement of the pattern shift is not possible in this region. Positions of the respective boundaries L₁, L₂ and R₁, R₂ are measured in the manner described below. Any measuring means or system may be used for this purpose as long as it is able to detect the position of boundaries. Among others, a line width measuring instrument such as an auto-telecomparator is preferable. The boundary position measurement is performed, as follows: (1) detecting the position of the left side boundary L₁ between the diffusion layer and the non-diffusion layer which underlie the oxide film layer 6, and storing the detected boundary position; (2) moving a stage on which a specimen is mounted, in the Y axis direction by a predetermined distance (500 µm, for example) so as to avoid influence of the crown C on the measurement, and thereafter detecting the position of the left side boundary L₂ between the diffusion layer and the non-diffusion layer which underlie the epitaxial growth layer 8, and storing the detected boundary position; (3) calculating the distance L between the boundary L₁ and the boundary L₂ by using the equation L = L₁ - L₂; (4) moving the stage in the X axis direction by a predetermined distance (80µm, for example), after that detecting the position between the right side boundary R₁ between the diffusion layer and the non-diffusion layer which underlie the oxide film layer 6, and storing the detected boundary position; (5) moving the stage in the Y axis direction by a predetermined distance (500µm, for example) so as to avoid influence of the crown C on the measurement, and thereafter detecting the position of the right side boundary R₂ between the diffusion layer and the non-diffusion layer which underlie the epitaxial growth layer 8, and storing the detected boundary position; and (6) calculating the distance R between the boundary R₁ and the boundary R₂ by using the equation R = R₁ - R₂. The displacement of the pattern, namely the pattern shift PS can be calculated by the following equation (I): PS = {(L+R)/2} /T where L is the displacement of said pattern measured at one edge thereof (the left edge in the illustrated embodiment), R is the displacement of said pattern measured at an opposite edge thereof (the right edge in the illustrated embodiment), and T is the thickness of the epitaxial growth layer. The pattern shift measurement was performed under the following conditions. 1) Specimens CZ p-type semiconductor wafer:<111> off-angle 3° 30' in<112> 100 , 10-200Ωcm, OF<110> Buried diffusion layer:Sb, 15 Ω/□, depth 8mm Width of the buried diffusion layer:80µm 2) Photolithography The oxide film on a substrate was removed by buffered hydrofluoric acid, and after that an oxide film of 600nm in thickness was formed by thermal oxidation process. Subsequently, a raised lattice-like oxide film pattern having a line with of 50µm and a line pitch of 5 mm was formed by a known photolithography. 3) Epitaxial growth 10µm, 1.6Ωcm Reaction furnace used: Cylindrical furnace Reaction temperature: 1150°C Reaction rate: 0.30µm/min Reaction pressure: 760 Torr 4) Measurement By using an auto-telecomparator (an instrument for measurement of minimal length), positions of the respective boundaries were measured in the same procedure as described above (at that time, the stage was moved by a distance same as the distance as exemplarily specified above). The same position was measured thirty (30) times with the results described as follows. Thickness of epitaxial layer (T): 10.02µm Mean value of L₁ : 60.54 Mean value of L₂ : 62.67 Mean value of L: 2.13 Mean value of R₁ : 61.37 Mean value of R₂ : 63.61 Mean value of R: 2.29 Mean value of pattern shift: 0.22 Standard deviation of pattern shift: 0.005 For comparative purposes, by using semiconductor wafers fabricated by the same procedure as described above, pattern shift was measured by a conventional measuring method (angular lapping and stain method). The results indicated that a mean value of pattern shift was substantially the same as that taken by the measurement of this invention but a standard deviation of pattern shift was 0.102. As evidenced from the foregoing results, the measurement according to this invention can measure pattern shift with an accuracy which is about twenty (20) times the accuracy of the conventional measuring method. In the embodiment described above, the buried diffusion layer is antimony (Sb). The method of this invention is also applicable to buried diffusion layers of other impurities such as boron (B), phosphorous (P) and arsenic (As). In addition, the pattern formed on a surface of the semiconductor wafer in the form of a groove or a ridge may be formed only by oxidation without following diffusion with impurities. As described above, according to the method of this invention, it is possible to measure the pattern shift of the epitaxial layer on a semiconductor wafer in a short period of time, with a high accuracy and at a low cost. | A method of measuring pattern shift of a semi-conductor wafer (2), comprising the steps of: forming a pattern (4) composed of a groove or a ridge on the semiconductor wafer (2); forming at least one strip of oxide film layer (6) extending over and across said pattern (4); thereafter, performing an epitaxial growing process to form an epitaxial layer (8) over said semiconductor wafer (2); measuring the lateral position of said pattern (4) both on said epitaxial layer (8) and on said oxide film layer (6); and comparing the lateral position of said pattern (4) measured on said epitaxial layer (8) with the position of said pattern (4) measured on said oxide film layer (6) so as to determine a displacement of said pattern (4). A method according to claim 1, wherein pattern shift PS of said pattern (4) is determined according to the following equation: PS = {(L+R)/2} /T where L is the displacement of said pattern (4) measured at one edge thereof, R is the displacement of said pattern (4) measured at an opposite edge thereof, and T is the thickness of said epitaxial layer (8). A method according to claim 1, wherein said pattern (4) and said at least one oxide film layer (6) cross at right angles to one another. A method according to claim 3, wherein the number of said oxide film layer (6) is plural, said pattern (4) and plurality of said oxide film layer strips (6) jointly forming a lattice-like pattern. A method according to claim 1, wherein said oxide film layer (6) has a width in the range of from 50 to 200µm. | SHINETSU HANDOTAI KK; SHIN-ETSU HANDOTAI COMPANY LIMITED | NAGOYA TAKATOSHI; NAGOYA, TAKATOSHI |
EP-0490195-B1 | 490,195 | EP | B1 | EN | 19,980,610 | 1,992 | 20,100,220 | new | C09D11 | C09B33, B41J2 | C09D11, C09B31 | C09B 31/18, C09D 11/00C2D | Ink, Ink-jet recording process, and instrument making use of the ink | Provided is an ink comprising at least water, a water-soluble organic solvent, and a dye, the dye comprising a compound represented by the general formula (I): wherein R₁, R₂, and R₃ are respectively hydrogen or SO₃M; R₄ is hydrogen, OCH₃, NH₂, NHCONH₂, or SO₃M; R₅ is hydrogen or SO₃M; R₆ is hydrogen or NH₂; R₇ is hydrogen, CH₃, or OCH₃; R₈ is hydrogen, COOM, or SO₃M; R₅ is hydrogen and R₈ is COOM when both of R₄ and R₆ are respectively NH₂; M is an alkali metal, ammonium, or organic ammonium; and m is 0 or 1, or a compound represented by the general formula (II): wherein R₁ is hydrogen, CH₃, COOM, or SO₃M; R₂ is hydrogen, CH₃, or COOM; R₃ is hydrogen, chlorine, COOM, or SO₃M; R₄ is hydrogen, OCH₃, NH₂, NHCONH₂, or SO₃M; R₅ is hydrogen or SO₃M; R₆ is hydrogen or NH₂; R₇ is hydrogen, CH₃, or OCH₃; R₈ is hydrogen, COOM, or SO₃M; R₅ is hydrogen and R₈ is COOM when both of R₄ and R₆ are respectively NH₂; M is an alkali metal, ammonium, or organic ammonium; and m is 0 or 1. | BACKGROUND OF THE INVENTIONField of the InventionThe present invention relates to an ink, an ink jet recording method, and an instrument employing the ink. More particularly, the present invention relates to an ink which provides an excellent water-resistant printed image on non-coated paper, and provide a printed image having improved resistance against indoor discoloration on coated paper (paper having a pigment-coating layer), and an ink jet recording process, an ink jet device, an ink jet recording apparatus, and an ink cartridge employing the above ink.Related Background ArtA variety of ink compositions are hitherto known for ink jet recording. In recent years, research and development are comprehensively being made to for improving the composition and the properties of the ink to conduct satisfactory recording on non-coated paper such as paper for copying, paper for reporting, notebooks, letter paper, bond paper, continuous business forms, and the like.For example, inks involves the problems as below. Inks generally contain a high-boiling organic solvent such as glycol for prevention of drying-up and clogging. When printing is conducted on a recording medium with such an ink, the printed images runs and becomes blurred, or scraped caused by sweat, a water drop, or the like, since the coloring matter used in the ink is a water-soluble dye. Further, full-color images which are printed on coated paper for forming the image clearly, come to be discolored disadvantageously even in a room where the direct sun light illumination is excluded, although sufficient light-fastness and weatherability are required to the color images. DE-A-3619573 discloses napthtalene trisazo compounds having a -SO3M group in the meta position of a terminal phenyl group. These compounds are used as dyes on recording liquids.EP-A-0422668 (which according to Article 54 (3) EPC belongs to the prior art for some of the contracting states) also discloses recording liquids containing naphthalene trisazo dyes. SUMMARY OF THE INVENTIONThe present invention intends to provide an ink which provides printed images with sufficient durability on non-coated paper, and provides printed images with little discoloration on coated paper.The present invention further provides an ink jet recording method and an instrument employing the ink.The present invention provides an ink comprising at least water, a water-soluble organic solvent, and a dye, the dye comprising a compound represented by the general formula (I): wherein R1, R2, and R3 are respectively hydrogen or SO3M; R4 is hydrogen, OCH3, NH2, NHCONH2, or SO3M; R5 is hydrogen or SO3M; R6 is hydrogen or NH2; R7 is hydrogen, CH3, or OCH3; R8 is hydrogen, COOM, or SO3M; R5 is hydrogen and R8 is COOM when both of R4 and R6 are respectively NH2; M is an alkali metal, ammonium, or organic ammonium; and m is 0 or 1.The present invention also provide an ink comprising at least water, a water-soluble organic solvent, and a dye, the dye comprising a compound represented by the general formula (II): wherein R1 is hydrogen, CH3, COOM, or SO3M; R2 is hydrogen, CH3, or COOM; R3 is hydrogen, chlorine, COOM, or SO3M; R4 is hydrogen, OCH3, NH2, NHCONH2, or SO3M; R5 is hydrogen or SO3M; R6 is hydrogen or NH2; R7 is hydrogen, CH3, or OCH3; R8 is hydrogen, COOM, or SO3M; R5 is hydrogen and R8 is COOM when both of R4 and R6 are respectively NH2; M is an alkali metal, ammonium, or organic ammonium; and m is 0 or 1.The present invention still also provides an ink jet recording process of conducting recording by ejecting ink droplets from an orifice in response to a recording signal, wherein the ink as described above is used.The present invention further provides an ink jet device comprising an ink storing member impregnated with a recording liquid, and a head having an orifice for ejecting the recording liquid as droplets, wherein the ink as described above is used.The present invention still further provides an ink jet recording apparatus comprising an ink jet device comprising an ink storing member impregnated with a recording liquid, and a head having an orifice for ejecting the recording liquid, wherein the ink as described above is used.The present invention still further provides an ink cartridge comprising an ink bag impregnated with a recording liquid comprising an ink, wherein the ink as described above is used.BRIEF DESCRIPTION OF THE DRAWINGSFig. 1A and Fig. 1B illustrate a longitudinal cross section and a transverse cross section, respectively, of a head of an ink jet recording apparatus.Fig. 2 is a perspective illustration of the appearance of a head having a multiple set of the heads as shown in Fig. 1A and 1B.Fig. 3 is a perspective illustration of an example of an ink jet recording apparatus.Fig. 4 is a longitudinal cross-sectional illustration of an ink cartridge.Fig. 5 is a perspective illustration of a recording device.DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTSPreferred embodiments are described below in detail.The present invention is characterized mainly by use of a dye having a specified structure as the coloring material of ink, thereby providing an ink which gives durable printed images on various non-coated paper and gives less discoloring images on coated paper, and providing also an ink jet recording method and instruments employing the ink.The dyes represented by the general formulae (I) and (II), which are used in the present invention and mainly characterizing the present invention, include any of the dyes of the above general formulae, and may be used singly or in combination of two or more thereof. Further, the dye may be used in combination with another dye which is not included in the dyes of the above general formulae.Among the dyes of the general formula (I), particularly preferred are those shown below: Among the dyes of the general formula (II), particularly preferred are those shown below: Among the dyes shown above, particularly preferred ones, in view of the effect of the present invention, are the compounds represented by the general formula (I) in which one of R1, R2, and R3 is SO3M, m is 0, and totally two or three SO3M groups are contained, and the compounds represented by the general formula (II) in which none or one of R1, R2, and R3 is SO3M, none or one of R4, R5, R6, R7, and R8 is SO3M, m is 0, and totally two or three SO3M groups are contained.The content of the dye in the ink depends on the kinds of the components of the liquid medium and the properties required to the ink. Generally, the content is in the range of from about 0.2 to about 20 % by weight, preferably from 0.5 to 10 % by weight, more preferably from 1 to 5 % by weight of the whole ink.The liquid medium used in the present invention is a mixture of water and a water-soluble organic solvent. The water may be ordinary water but is preferably deionized water. The organic solvent includes alkyl alcohols having 1 to 5 carbons such as methyl alcohol, ethyl alcohol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, sec-butyl alcohol, tert-butyl alcohol, isobutyl alcohol, n-pentanol, etc., and halogenated derivatives thereof; amides such as dimethylformamide, dimethylacetamide, etc.; ketones and ketoalcohols such as acetone, diacetone alcohol, etc.; ethers such as tetrahydrofuran, dioxane, etc.; oxyethylene or oxypropylene addition products such as diethylene glycol, triethylene glycol, tetraethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol, etc.; alkylene glycols having alkylene group of 2 to 6 carbons such as ethylene glycol, propylene glycol, trimethylene glycol, butylene glycol, 1,2,6-hexane triol, hexylene glycol, etc.; thiodiglycol; glycerin; ethers of a polyhydric alcohol with a lower alkyl such as ethylene glycol monomethyl (or monoethyl) ether, diethylene glycol monomethyl (or monoethyl) ether, triethylene glycol monomethyl (or monoethyl) ether, etc.; diethers of a polyhydric alcohol with a lower alkyl such as triethylene glycol dimethyl (or diethyl) ether, tetraethylene glycol dimethyl (or diethyl) ether, etc.; sulfolane, N-methyl-2-pyrrolidone, 1,3-dimethyl-2-imidazolidinone, and the like.The content of the aforementioned water soluble organic solvent is generally in the range of from 2 to 50 %, preferably 2 to 30 % by weight of the whole ink. The solvent may be used singly or in combination of two or more thereof.The main constituents of the ink of the present invention is described above. Other additives such as a dispersant, a surfactant, a viscosity controlling agent, a surface tension controlling agent, a fluorescent whitening agent, and the like may be added to the ink, if necessary, within the range that the object of the present invention is achieved. The examples are viscosity controlling agents such as polyvinyl alcohol, cellulose derivatives; various surface active agents of cation type, anion type, and nonion type; surface tension controlling agents such as diethanolamine, and triethanolamine; pH controlling agents such as buffer solutions; mildewproofing agents; and the like.For formulation of the ink used for ink jet recording which gives electric charge to the ink, there is added a resistivity controlling agent such as inorganic salts including lithium chloride, ammonium chloride, sodium chloride.The ink of the present invention is employed particularly suitable for an ink jet recording method of recording by ejecting ink droplets by a bubbling phenomenone upon thermal energy, and has characteristic of stabilizing highly the ink ejection without causing satellite dots or other disadvantages. In this case, thermal properties such as specific heat, thermal expansion coefficient, and thermal conductivity may be adjusted, if necessary.The ink itself of the present invention is desirably adjusted to have a surface tension at 25°C of from 30 to 68 dyne/cm, and a viscosity at 25°C of not more than 15 cP, preferably not more than 10 cP, more preferably not more than 5 cP for the purpose of solving the problems of running of ink, drying property of recorded images, and permeability of ink on non-coated paper or other recording mediums, and for the purpose of improving the matching of the ink with an ink jet head.In order to adjust the properties of the ink as above and to solve the problems in recording on non-coated paper, the water content in the ink of the present invention made to be in the range of from 50 to 95 % by weight, preferably from 60 to 90 % by weight.The ink of the present invention, which is employed particularly suitably for an ink jet recording method for recording by ejecting ink droplets by thermal energy, is naturally useful also for general writing utensils.The methods and the apparatus suitable for the use of the ink of the present invention are those that provide thermal energy to ink in a cell in a recording head in correspondence with recording signals to form ink droplets by the thermal energy.An example of the constitution of the heads, which is a main portion of the apparatus, is shown in Fig. 1A, Fig. 1B, and Fig. 2.A head 13 is formed by bonding a plate of glass, ceramics, or plastics having a groove 14 with a heat-generating head 15. (The type of the head is not limited to the one shown in the drawing.) The heat-generating head 15 is constituted of a protection layer 16 formed of silicon oxide or the like, aluminum electrodes 17-1 and 17-2, a heat-generating resistance layer 18 formed of nichrome or the like, a heat accumulation layer 19, and a substrate plate 20 having heat-releasing property made of alumina or the like.Ink 21 reachs the ejection orifice 22 (a fine pore), forming a meniscus by action of pressure P not shown in the figure.On application of an electric signal to the electrodes 17-1 and 17-2, the region designated by a symbol n on the heat-generation head 15 generates abruptly heat to form a bubble in the ink 21 at the position adjacent thereto. The pressure generated by the bubble pushes out the meniscus 23 and ejects the ink 21, as a recording droplets 24, and the ink droplets are propelled to a recording medium 25. Fig. 2 illustrates exterior appearance of a multi-head constructed by juxtaposing a multiplicity of heads shown in Fig. 1A. The multi-head is prepared by bonding a glass plate having multi-grooves with a heat-generation head 28 similar to the one described in Fig. 1A.Incidentally, Fig. 1A is a cross-sectional view of the head 13 along an ink flow path, and Fig. 1B is a cross-sectional view of the head at the line A-B in Fig. 1A.Fig 3 illustrates an example of the ink-jet recording apparatus having such a head mounted therein.In Fig. 3, a blade 61 as a wiping member is held at one end by a blade-holding member, forming a fixed end in a shape of a cantilever. The blade 61 is placed at a position adjacent to the recording region of the recording head, and in this example, is held so as to protrude into the moving path of the recording head. A cap 62 is placed at a home position adjacent to the blade 61, and is constituted such that it moves in the direction perpendicular to the moving direction of the recording head to come into contact with the ejection nozzle face to cap the nozzles. An ink absorption member 63 is provided at a position adjacent to the blade 61, and is held so as to protrude into the moving path of the recording head in a manner similar to that of the blade 61. The aforementioned blade 61, the cap 62, the absorption member 63 constitute an ejection-recovery section 64, the blade 61 and the absorption member 63 remove off water, dust, and the like from the ink ejecting nozzle face.A recording head 65 has an ejection energy generation means for ejection, and conducts recording by ejecting ink toward a recording medium opposing to the ejection nozzle face. A carriage 66 is provided for supporting and moving the recording head 65. The carriage 66 is engaged slideably with a guide rod 67. A portion of the carriage 66 is connected (not shown in the figure) to a belt 69 driven by a motor 68, so that the carriage 66 is movable along the guide rod 67 to the recording region of the recording head and the adjacent region thereto.The constitution of a paper delivery portion 51 for delivery of a recording medium and a paper delivery roller 52 driven by a motor not shown in the figure delivers the recording medium to the position opposing to the ejecting nozzle face of the recording head, and the recording medium is discharged with the progress of the recording to paper discharge portion provided with paper-discharge rollers 53.In the above constitution, the cap 62 of the ejection-recovery portion 64 is out of the moving path of the recording head 65, while the blade 61 is made to protrude into the moving path. Therefore, the ejecting nozzle face of the recording head 65 is wiped therewith. The cap 62 moves to protrude toward the moving path of the recording head when the cap 62 comes into contact for capping with the ejecting nozzle face of the recording head.At the time when the recording head 65 moves from the home position to the record-starting position, the cap 62 and the blade 61 are at the same position as in the above-mentioned wiping time, so that the ejection nozzle face of the recording head is wiped also in this movement.The recording head moves to the home position not only at the end of the recording and at the time of ejection recovery, but also at a predetermined interval during movement for recording in the recording region. By such movement, the wiping is conducted.Fig. 4 illustrates an example of the ink cartridge containing ink to be supplied through an ink supplying member such as a tube. The ink container portion 40, for example an ink bag, contains an ink to be supplied, and has a rubber plug 42 at the tip. By inserting a needle (not shown in the drawing) into the plug 42, the ink in the ink bag 40 becomes suppliable. An absorption member 44 absorbs waste ink.The ink container portion has preferably a liquid-contacting face made of polyolefin, especially polyethylene in the present invention.The ink-jet recording apparatus used in the present invention is not limited to the above-mentioned one which has separately a head and an ink cartridge. Integration thereof as shown in Fig. 5 may suitably be used.In Fig. 5, a recording device 70 houses an ink container portion such as an ink absorption member, and the ink in the ink absorption member is ejected from a head 71 having a plurality of orifices. The material for the ink absorption member is preferably polyurethane in the present invention.Air-communication opening 72 is provided to communicate interior of the cartridge with the open air.The recording device 70 may be used in place of the recording head shown in Fig. 3, and is readily mountable to and demountable from the carriage 66.The present invention is described in more detail referring to examples and comparative examples. The part(s) and % in the description are based on weight unless otherwise mentioned.Examples 1 to 10 and Comparative Examples 1 and 2The components shown below were mixed and dissolved, and the resulting solution was filtered under pressure through a filter having pores of 1 µm in diameter to obtain the inks of the examples and the comparative examples as shown in Table 1. Example 1Diethylene glycol25 partsPure water72 partsExemplified dye I-(1)3 PartsExample 2Diethylene glycol30 partsPure water67 partsExemplified dye I-(2)3 PartsExample 3Ethylene glycolol20 partsPure water76 partsExemplified dye I-(4)4 PartsExample 4Glycerin20 partsPure water75 partsExemplified dye I-(6)5 Parts Example 5Triethylene glycol25 partsEthylene glycol monomethyl ether15 partsPure water55 partsExemplified dye I-(9)5 PartsExample 6Glycerin20 partsPure water76 partsExemplified dye I-(10)4 PartsExample 7Glycerin15 partsN-methyl-2-pyrrolidone10 partsPure water71 partsExemplified dye I-(13)4 PartsExample 8Triethylene glycol20 partsEthylene glycol monomethyl ether15 partsPure water60 partsExemplified dye I-(14)5 PartsExample 9Ethylene glycol25 partsN-methyl-2-pyrrolidone10 partsPure water61 partsExemplified dye I-(15)4 Parts Example 10Diethylene glycol25 partsPolyethylene glycol10 partsN,N-dimethylimidazolidinone5 partsPure water57 partsExemplified dye I-(18)3 PartsComparative Example 1Diethylene glycol30 partsPure water67 partsC.I. Food Black 13 PartsComparative Example 2Ethylene glycol20 partsPure water76 partsC.I. Food Black 24 PartsWith the inks of the above Examples 1 to 10, solid printing was conducted by means of a recording apparatus (BJ-130, made by Canon K.K.) having an On-Demand type of multiple orifice head for conducting recording by giving heat energy to the ink in the recording head to form liquid droplets, thus preparing printed pieces in the size of 10 × 20 mm. The test paper used were paper recommended for Canon NP-6150, Canon NP-Dry, Noizidlerpaper, and Proberbond paper. The optical densities of the printed matters were all within the range of from 1.30 to 1.45. The water resistance of the print was evaluated by immersing the printed piece in a stagnant water at 20°C for 5 minutes and then measuring the degree of decrease of the optical density. All of the printed pieces exhibited the degree of the decrease of not more than 15 %, and was sufficiently water-resistant. On the other hand, the inks of Comparative Examples 1 and 2 were tested for the water resistance in the same manner as above. The degree of decrease of the optical density was not less than 50 % for all samples.Further, printing was conducted on specified paper for Canon Color Bubble Jet Copia in the same manner as above, and the printed matter was kept standing in a test chamber in which ozone concentration was being maintained at 30 ppm for 2 hours. The color difference (ΔE*ab) caused by the standing in the test chamber was measured. The evaluation results are graded by the standards as below: ○ :ΔE*ab < 5Δ :5 ≦ ΔE*ab ≦ 10× :ΔE*ab > 10 The printed matters prepared with the inks of Examples 1 to 10 were all evaluated as ○ (ΔE*ab < 5), showing no remarkable discoloration. On the contrary, that of Comparative Example 1 was evaluated as ▵, showing relatively slight discoloration, but that of Comparative Example 2 was evaluated as ×, showing significant discoloration.Examples 11 to 20 and Comparative Examples 3 and 4The components shown below were mixed and dissolved, and the resulting solution was filtered under pressure through a filter having pores of 1 µm in diameter to obtain the inks of the examples and the comparative examples as shown in Table 2. Example 11Diethylene glycol30 partsPure water67 partsExemplified dye II-(1)3 PartsExample 12Ethylene glycol25 partsPure water71 partsExemplified dye II-(3)4 PartsExample 13Glycerin15 partsPure water82 partsExemplified dye II-(5)3 PartsExample 14 Diethylene glycol20 partsPure water76 partsExemplified dye II-(6)4 PartsExample 15Triethylene glycol20 partsN-methyl-2-pyrrolidone10 partsPure water65 partsExemplified dye II-(8)5 PartsExample 16Glycerin20 partsPure water77 partsExemplified dye II-(10)3 PartsExample 17Polyethylene glycol 30020 partsGlycerin10 partsPure water66 partsExemplified dye II-(11)4 PartsExample 18Diethylene glycol25 partsEthylene glycol monomethyl ether10 partsPure water60 partsExemplified dye II-(13)5 PartsExample 19Ethylene glycol30 parts N-methyl-2-pyrrolidone5 partsPure water61 parts Exemplified dye II-(16) 4 parts Example 20Triethylene glycol25 partsGlycerin10 partsN,N-dimethylimidazolidinone5 partsPure water55 partsExemplified dye II-(18)5 PartsComparative Example 3Diethylene glycol30 partsPure water65 partsC.I. Food Black 15 PartsComparative Example 4Triethylene glycol25 partsPure water71 partsC.I. Food Black 24 PartsWith the inks of the above Examples 11 to 20, solid printing was conducted by means of a recording apparatus (BJ-130, made by Canon K.K.) having an On-Demand type of multiple orifice head for conducting recording by giving heat energy to the ink in the recording head to form liquid droplets, thus preparing printed pieces in the size of 10 × 20 mm. The test paper used were paper recommended for Canon NP-6150, Canon NP-Dry, Noizidlerpaper, and Proberbond paper. The optical densities of the printed matters were all within the range of from 1.30 to 1.45. The water resistance of the print was evaluated by immersing the printed piece in a stagnant water at 20°C for 5 minutes and then measuring the degree of decrease of the optical density. All of the printed pieces exhibited the degree of the decrease of not more than 15 %, and was sufficiently water-resistant. On the other hand, the inks of Comparative Examples 3 and 4 were tested for the water resistance in the same manner as above. The degree of decrease of the optical density was not less than 50 % for all samples.Further, printing was conducted on specified paper for Canon Color Bubble Jet Copia in the same manner as above, and the printed matter was kept standing in a test chamber in which ozone concentration was being maintained at 30 ppm for 2 hours. The color difference (ΔE*ab) caused by the standing in the test chamber was measured. The evaluation results are graded by the standards as below: ○ :ΔE*ab < 5Δ :5 ≦ ΔE*ab ≦ 10× :ΔE*ab > 10 The printed matters prepared with the inks of Examples 11 to 20 were all evaluated as ○ (ΔE*ab < 5), showing no remarkable discoloration. On the contrary, that of Comparative Example 3 was evaluated as ▵, showing relatively slight discoloration, but that of Comparative Example 4 was evaluated as ×, showing significant discoloration.Example 21Inks (a) to (e) were prepared in the same manner as in Example 1 except that the dyes were changed respectively to the mixture having the composition as below. (a)I - (1)1.5 partsII - (6)1.5 parts(b)I - (5)1.8 partsII -(12)1.2 parts(c)I - (8)2.0 partsII - (4)1.0 part(d)I - (8)2.0 partsII -(10)1.0 part(e)I -(17)1.0 partII - (2)2.0 parts With these inks, printing was conducted on the aforementioned kinds of paper by means of the above recording apparatus BJ-130. The water-resistance was evaluated in the same manner as above, and was found that the degree of decrease of the optical density was not more than 15 % for all the printed pieces. The discoloration by ozone was evaluated as above and was found that the ΔE*ab value was less than 5 for all the printed pieces. Further, the printed pieces were exposed to indoor light for 6 months, and found that the color change after the 6 month exposure was less than 5 in terms of ΔE*ab.Example 22The aforementioned printed matters of Examples 1 to 20 prepared by printing on specified paper for Canon Color-Bubble Jet Copia coated paper (made by Canon Inc., designated paper for BJ-A1) with the recording apparatus BJ-130 were tested for light-fastness by exposing light for 100 hours by Xenon fade-o-meter (made by Atlas Co.). The degree of decrease of the optical density was not higher than 30 % for all the samples. On the contrary, that for the Comparative Examples 1 and 3 was higher than 60 %.Further, the discoloration of the above printed matters after 6 months of exposure to indoor light was less than 5 in terms of ▵E*ab, while that of Comparative Examples 2 and 4 was both more than 10.From the description above, it is clear that inks which provides printed matters having light-fastness on non-coated paper or which provides printed matters having resistance to discoloration on coated paper are provided by selecting the dye having the specified structure as the coloring matter according to the present invention. | Claims for the following Contracting States : AT, BE, CH, DK, ES, GR, IT, LI, LU, NL, SEAn ink comprising at least water, a water-soluble organic solvent, and a dye, the dye comprising a compound represented by the general formula (I): wherein R1, R2, and R3 are respectively hydrogen or SO3M; R4 is hydrogen, OCH3, NH2, NHCONH2, or SO3M; R5 is hydrogen or SO3M; R6 is hydrogen or NH2; R7 is hydrogen, CH3, or OCH3; R8 is hydrogen, COOM, or SO3M; R5 is hydrogen and R8 is COOM when both of R4 and R6 are respectively NH2; M is an alkali metal, ammonium, or organic ammonium; and m is 0 or 1.An ink according to Claim 1, wherein one of R1, R2, and R3 is SO3M, m is 0, and two or three SO3M groups in total are included in the compound of the general formula (I).An ink according to Claim 1, wherein the ink contains the compound represented by the general formula (I) in an amount of from 0.2 to 20 % by weight of the whole ink. An ink comprising at least water, a water-soluble organic solvent, and a dye, the dye comprising a compound represented by the general formula (II): wherein R1 is hydrogen, CH3, COOM, or SO3M; R2 is hydrogen, CH3, or COOM; R3 is hydrogen, chlorine, COOM, or SO3M; R4 is hydrogen, OCH3, NH2, NHCONH2, or SO3M; R5 is hydrogen or SO3M; R6 is hydrogen or NH2; R7 is hydrogen, CH3, or OCH3; R8 is hydrogen, COOM, or SO3M; R5 is hydrogen and R8 is COOM when both of R4 and R6 are respectively NH2; M is an alkali metal, ammonium, or organic ammonium; and m is 0 or 1.An ink according to Claim 4, wherein none or one of R1, R2, and R3 is SO3M, none or one of R4, R5, R6, R7, and R8 is SO3M, m is 0, and two or three SO3M groups in total are included in the compound of the general formula (II).An ink according to Claim 4, wherein the ink contains the compound represented by the general formula (II) in an amount of from 0.2 to 20 % by weight of the whole ink.An ink according to Claim 1 or 4, wherein the ink contains the water-soluble organic solvent in an amount of from 2 to 50 % by weight of the whole ink.An ink according to Claim 1 or 4, wherein the ink contains the water in an amount of from 50 to 95 weight % of the whole ink.An ink jet recording process of conducting recording by ejecting ink droplets from an orifice in response to a recording signal, using the ink according to any one of the claims 1 to 3, 7, and 8, or 4 to 6, 7, and 8. An ink jet recording process according to Claim 9, wherein the ink droplets are ejected by action of thermal energy. An ink jet recording process according to Claim 9, wherein the recording is conducted on pigment-coated paper. An ink jet device comprising an ink storing member impregnated with a recording liquid, and a head having an orifice for ejecting the recording liquid as droplets, the recording liquid comprising an ink according to any one of claims 1 to 3, 7, and 8, or 4 to 6, 7, and 8.An ink jet device according to Claim 12, wherein the ink storing member is an ink absorber or an ink bag.An ink jet device according to Claim 12 or 13, wherein the head has a heating head to provide to the ink a heat energy for ejecting ink droplets. An ink jet recording apparatus comprising an ink jet device comprising an ink storing member impregnated with a recording liquid, and a head having an orifice for ejecting the recording liquid, the recording liquid comprising an ink according to any one of claims 1 to 3, 7, and 8, or 4 to 6, 7, and 8. An ink jet recording apparatus according to Claim 15, wherein the ink storing member is an ink absorber or an ink bag.An ink jet recording apparatus according to Claim 15 or 16, wherein the head has a heating head to provide to the ink a heat energy for ejecting ink droplets. An ink cartridge comprising an ink bag impregnated with a recording liquid comprising an ink according to any one of claims 1 to 3, 7, and 8 or 4 to 6, 7, and 8. A method for producing the ink according to any one of the claims 1 to 3, 7, and 8, or 4 to 6, 7, and 8, characterized by mixing and dissolving specified amounts of water, water-soluble organic solvent and dye, andfiltering the resulting solution.Claims for the following Contracting States : DE, FR, GBAn ink comprising at least water, a water-soluble organic solvent, and a dye, the dye having two SO3M groups per molecule and comprising a compound represented by the general formula (I): wherein one of R1, R2 and R3 is SO3M and the others are hydrogen; R4 is hydrogen, OCH3, NH2, NHCONH2, or SO3M; R5 is hydrogen or SO3M; R6 is hydrogen or NH2; R7 is hydrogen, CH3, or OCH3; R8 is hydrogen, COOM, or SO3M; R5 is hydrogen and R8 is COON when both of R4 and R6 are respectively NH2; M is an alkali metal or ammonium, with the provision that A is not An ink according to Claim 1, wherein the ink contains the compound represented by the general formula (I) in an amount of from 0.2 to 20 % by weight of the whole ink. An ink comprising at least water, a water-soluble organic solvent, and a dye, the dye comprising a compound represented by the general formula (II): wherein R1 is hydrogen, CH3 or COOM ; R2 is hydrogen, CH3 or COOM; R3 is hydrogen, chlorine or COOM ; R4 is hydrogen, OCH3, NH2 or NHCONH2; R5 is hydrogen ; R6 is hydrogen or NH2; R7 is hydrogen, CH3 or OCH3; R8 is hydrogen or COOM; R8 is COOM when both of R4 and R6 are respectively NH2; M is an alkali metal, ammonium or organic ammonium.An ink according to Claim 3, wherein none or one of R1, R2, and R3 is SO3M, none or one of R4, R5, R6, R7, and R8 is SO3M, and two or three SO3M groups in total are included in the compound of the general formula (II).An ink according to Claim 3, wherein the ink contains the compound represented by the general formula (II) in an amount of from 0.2 to 20 % by weight of the whole ink.An ink according to Claim 1 or 3, wherein the ink contains the water-soluble organic solvent in an amount of from 2 to 50 % by weight of the whole ink.An ink according to Claim 1 or 4, wherein the ink contains the water in an amount of from 50 to 95 weight % of the whole ink.An ink jet recording process of conducting recording by ejecting ink droplets from an orifice in response to a recording signal, using the ink according to any one of the claims 1, 2, 6 and 7 or 3 to 5, 6 and 7. An ink jet recording process according to Claim 8, wherein the ink droplets are ejected by action of thermal energy. An ink jet recording process according to Claim 9, wherein the recording is conducted on pigment-coated paper. An ink jet device comprising an ink storing member impregnated with a recording liquid, and a head having an orifice for ejecting the recording liquid as droplets, the recording liquid comprising an ink according to any one of the claims 1, 2, 6 and 7 or 3 to 5, 6 and 7.An ink jet device according to Claim 11, wherein the ink storing member is an ink absorber or an ink bag.An ink jet device according to Claim 11 or 12, wherein the head has a heating head to provide to the ink a heat energy for ejecting ink droplets. An ink jet recording apparatus comprising an ink jet device comprising an ink storing member impregnated with a recording liquid, and a head having an orifice for ejecting the recording liquid, the recording liquid comprising an ink according to any one of the claims 1, 2, 6 and 7 or 3 to 5, 6 and 7. An ink jet recording apparatus according to Claim 14, wherein the ink storing member is an ink absorber or an ink bag.An ink jet recording apparatus according to Claim 14 or 15, wherein the head has a heating head to provide to the ink a heat energy for ejecting ink droplets. An ink cartridge comprising an ink bag impregnated with a recording liquid comprising an ink, according to any one of the claims 1, 2, 6 and 7 or 3 to 5, 6 and 7. A method for producing the ink according to any one of the claims 1, 2, 6 and 7, or 3 to 5, 6 and 7, characterized by mixing and dissolving specified amounts of water, water-soluble organic solvent and dye, andfiltering the resulting solution. | CANON KK; CANON KABUSHIKI KAISHA | EIDA TSUYOSHI; YAMAMOTO MAYUMI; YAMAMOTO TAKAO; EIDA, TSUYOSHI; YAMAMOTO, MAYUMI; YAMAMOTO, TAKAO; EIDA, TSUYOSHI, C/O CANON KABUSHIKI KAISHA; YAMAMOTO, MAYUMI, C/O CANON KABUSHIKI KAISHA; YAMAMOTO, TAKAO, C/O CANON KABUSHIKI KAISHA |
EP-0490204-B1 | 490,204 | EP | B1 | EN | 19,951,108 | 1,992 | 20,100,220 | new | F16F3 | F16J15 | F16J15, F16F3 | F16F 3/12, F16J 15/02B2, F16J 15/32B7B | Seal with spring energizer and method | The seal apparatus (10) includes a resilient member (12) having at least one sealing surface (14,16) thereon and an engagement surface (22) spaced up from the sealing surface. A spring's position (30) to bias the sealing surface and flexible or elastic means (32) are disposed in and about the spring in order to substantially increase the useful life of the resilient member. | The present application generally relates to seals for reciprocating and rotary applications and more particularly relates to seals which are loaded, or energized, by a spring, the seals being of a kind described in the precharacterizing portions of claims 1 and 7. Seals are generally formed from a resilient material and when disposed between adjacent surfaces are compressed to form a seal therebetween to prevent passage of fluids thereby. The inherent characteristics of the resilient material limit the load capability of seals made therefrom. Generally speaking, the deflection of a resilient seal results in a sealing force which is inconsistent over a range of deflection of the seal. This results in poor sealing capability when the resilient material is not sufficiently deflected and excessive wearing of the seal when it is subjected to greater deflection. To overcome these characteristics, seals have been used in combination with springs, for example, canted coil springs which can be manufactured so that within a certain range of deflection thereof the force developed remains relatively constant. The advantages of these types of springs is pointed out in U.S. Patent No. 4,655,462 to Balsells. When a canted coil spring is used in combination with a resilient material to form a seal, parameters such as the spring coil size, coil spacing, wire diameter, the angle the coils are canted with a centerline of the spring are, among others, used to tailor the resilient characteristics of the spring and the overall resilient characteristics of the seal to meet the needs of a proposed application. Disclosed in copending U.S. Patent Application Serial No. 496,329 is a combination of spring and elastic material which is disposed around and between a plurality of coils from modifying the force exerted by the spring in response to deflection of the spring along a loading direction. United Kingdom Patent laid open publication GB 21 69 378 A describes a coil spring including a plurality of convolutions interconnected with one another in a spaced-apart relationship to effect a helical structure exhibiting preselected acute angles relative to a centerline of the spring for exerting a constant force in a loading direction approximately normal to the centerline. The spring is placed in an operative relationship with a seal material to enable sealing between cooperative parts and to prevent passage of fluid there passed. German laid open publication DE 19 30 805 discloses a helical screw exhibiting a progressive loadline comprising a wire having a diameter between 1 and 2 cm and for particular use in automobiles. The spring is produced in conjunction with an elastic coating made of polyvinyl chloride of thickness 0.5 to 1.0 millimeters. This application also discloses a method for coating the spring with the plastic. In view of the above mentioned features of prior art it is the purpose of the present invention to improve a coiled spring seal, in particular of the kind described in GB 21 69 378 A, in such a fashion that the useful life of the seal is extended. SUMMARY OF THE INVENTIONThis purpose is achieved in accordance with the invention through the characterizing parts of claims 1 and 9, in conjunction with their respective precharacterizing portions, and by the method of claim 14. It has been found that the use of spring assembly, including coil springs with a flexible material in and around the coils, provides a spring energizer assembly used in combination with a seal which surprisingly extends the useful life of the seal, despite the fact that the spring energizer makes no contact with the sealing surface, but rather, biases the resilient seal material from a spaced apart position from the sealing surface. Sealing apparatus in accordance with the present invention generally includes a resilient member having at least one sealing surface thereon and including means defining a groove therein, with the groove being spaced apart from the sealing surface. A spring is disposed within the groove and flexible means, disposed in the groove with the spring, is provided for increasing the length of time that the sealing surface can effectively block the passage of fluid therepast when bearing against the surface moving relative thereto. This increased length of time is relative to the time that the sealing surface can effectively block the passage of fluid therepast when bearing against the surface moving relative therethrough when the flexible means is not present in the groove. Thus, the flexible means is effective in causing the life of the resilient ring member to be greater when the flexible means is disposed in the groove with the spring compared to the spring alone. In one embodiment of the present invention, the flexible means is disposed in and around the spring and may have a hollow or a solid cross-section. In addition, the flexible means may be bonded or not bonded to the spring, but in either case, it is not bonded to the resilient member. More particularly, the seal apparatus in accordance with the present invention may include a resilient ring member having at least one sealing surface thereon adapted for bearing against a rotating and/or reciprocating surface in order to prevent passage of fluid therepast. The groove may be circumferential and the spring may include a plurality of coil means, interconnected with one another in a spaced-apart relationship, for causing the spring assembly to exert a force in a loading direction approximately normal to the sealing surface in response to the deflection of the spring assembly along the loading direction. The flexible means, disposed around and between the plurality of coil means, is operable for both modifying the force exerted by the spring assembly in response to the deflection of the spring assembly and for causing the life of the resilient ring member to be greater than the life of the resilient ring member when the flexible means are not present. Another embodiment of the spring assembly may include a first plurality of coil means and a second plurality of coil means, the second plurality of coil means being disposed within the first plurality of coil means for causing the spring assembly to exert a generally constant force. The flexible means may include a coating of flexible material on the spring and may be of sufficient thickness to extend the useful life of the seal by more than 300 percent. More particularly, the resilient member may comprise polytetrafluorethylene and the flexible material may be a silicone elastomer. A method in accordance with the present invention for extending the useful life of a seal includes coating a spring with a flexible material and disposing the coated spring in a spaced-apart relationship with the sealing surface of the seal in a position for biasing the sealing surface against the sealing surface. BRIEF DESCRIPTION OF THE DRAWINGSA better understanding of the present invention may be had by consideration of the following detailed description, taken in conjunction with the accompanying drawings, in which: Figure 1 is a perspective view of a radial type seal suitable for reciprocating applications, generally including a plurality of coils inter-connected in a manner forming a radially resilient canted coil spring, with the spring being disposed in a groove with a flexible material; Figure 2 is a perspective view of an axial type seal in accordance with the present invention generally including a resilient member and a spring including a plurality of coils interconnected in a manner forming a garter-type axially resilient coil spring disposed in a groove along with a flexible material; Figure 3 is a load-deflection curve for a spring assembly in accordance with the present invention for the purpose of defining a nomenclature thereof; Figure 4a, b, c, d, e and g, show in cross-section a variety of spring assemblies utilizing canted-coil springs for a number of dynamic applications in accordance with the present invention; Figure 5 shows a round spring filled with an elastomer having a hollow core in a seal assembly; Figure 6a and b shows an elastomer filled with V-shaped flat straight length of spring suitable for use with a resilient material for forming a spring assembly in accordance with the present invention; Figure 7 shows an axial spring with an irregular shape and filled with an elastic material having a hollow cross-section in accordance with the present invention; Figures 8-10 show various inter cross-sectional configurations in accordance with the present invention; Figure 11 shows a spring with a partially filled elastomeric material protruding beyond the coil along one area of the miner axis of the spring and all around and between the coil, which can be encapsulated or coated; Figures 12, 14 show variations and encapsulation of coils of the present invention with an elastomer or plastic; Figures 15 a, b, c are cross section views of a spring and elastomer showing relative positions of the elastomer with respect to coils of the spring; Figures 16a and b are views of an alternative embodiment of the present invention with a spring assembly having a first and second plurality of coil means canted in the same direction along a common centerline and separated from one another; and Figures 17a and b show an alternative embodiment of the present invention in which the first and second plurality of coil means are canted in opposite directions. DETAILED DESCRIPTIONTurning now to Figure 1, there is shown seal apparatus 10 in accordance with the present invention generally showing a resilient member 12 having sealing surfaces 14, 16 and a shape defining a groove 20 which provides an engagement surface 22 which is spaced apart from the sealing surface 14 by a thin lip 26. A canted-coil spring 30, as hereinafter described, is disposed within the groove 20 in position biasing the engagement surface 22. A flexible, or jelly-like material, 32, disposed around the spring 30 provides a means for increasing the length of time that the sealing surface of 22 can effectively block the passage of fluid (not shown) therepast when bearing against a surface (not shown) moving relative thereto to greater than the second length of time that the sealing surface 14 can effectively block the passage of fluid therepast when bearing against the surface moving relative thereto when the material 32 is not present in the groove 20, as will be described hereinafter in greater detail. The combination of the material 32 with the spring substantially increases the usable life of the seal 10. The elastic, or jelly-like material 32, may be bonded to the spring or float around the spring cross-section without being attached to it. The material 32 can be an elastomer, plastic, paste, sealing caulk, grease, wax or any suitable material, but preferably a material such as silicone RTV 732, available from Dow Corning. It is believed that the material 32 effectively distributes the spring force and decreases dead volume, yet allows the spring to maintain a characteristic load deflection characteristic as will be hereinafter described in greater detail. The combination of the present invention must be distinguished from that shown in U.S. Patent No. 3,183,010 to Bram, in which an elastomer, bonded to a spring, is provided for the purpose of supporting the elastomer. An alternative embodiment 40 of the present invention for use in axial loading applications includes a resilient member 42 having sealing surfaces 44 and 46 and a shape defining a groove 50 having an inside surface 52 separated from the sealing surface 44 by a thin lip 54. Similar to the embodiment 10 shown in Figure 1, an elastic material 56 is disposed in the groove 50 for extending the useful life of the seal apparatus 40, as will be hereinafter described in greater detail. While any number of springs may be used to advantage in the present invention, as hereinafter described, particularly suitable are canted coil springs such as described in copending U.S. Patent Application Serial No. 496,329 filed on March 20, 1990, which specification and drawings are incorporated herewith by specific reference thereto, in order to describe canted coil springs suitable for use in the present invention and additionally described placement of elastomer in and about such coil springs. Figure 3 shows an exemplary load-deflection curve 60 for the purpose of illustrating the characteristics of canted coil resilient coil springs suitable for use in the seals 10, 40, in accordance with the present invention. As shown in Figure 3, when a load is applied to the spring 30, 58, the spring 30, 58 deflects in a generally linear fashion, as shown by the line segment 62, until it reaches a maximum load point 64 which represents the point at which, after the initial deflection, the load begins to remain relatively constant. It is to be appreciated that for an axially resilient spring 58, the load is applied axially and for a radially resilient spring 30, the load is applied radially. Between the minimum load point 64 and a maximum load point 66, the load deflection curve may be constant or show a slight increase, as shown in Figure 3. The area between the minimum load point 14 and the maximum load point 66 is known as the working deflection range 68. The spring 30, 58 is normally loaded for operation within this range, as indicated by a point 70. Loading of the spring 30, 58 beyond the maximum load point 66 results in an abrupt deflection response until it reaches a butt point 72, which results in a permanent set in the spring as a result of overloading. Also indicated in Figure 3 is the total deflection range of 74, which is defined as the deflection between the unloaded spring and the maximum load point 66. Turning to Figures 4a-g, there is shown various embodiments of the present invention suitable for dynamic applications. More specifically, the seal 80 includes a resilient member 82 with a groove 84 therein for containing a spring 86 with elastomer 88 having a hollow cross section, thereby producing a central void 90 therethrough. The elastic flexible material 88 may be of the type hereinabove described and the resilient member 82 may be of any suitable material, but preferably polytetrafluorethylene (PTFE) which may be filled or not filled, for example, with graphite, as commonly known. Figure 4b shows a seal 92 having an elastic member 94 with two grooves 96, 98, for supporting springs 100, 102 with elastic material 104, 106 having a hollow cross section. The seal 92 is suitable for rotary, reciprocating and static applications and, in addition, the spring 102, and elastomer 106, provides a secondary holding means in order to provide added sealing ability and better gripping actions so as to reduce possible movement of the seal assembly 92 in dynamic applications, primarily in rotary and oscillating service. Turning to Figure 4c, there is shown a seal apparatus 110 which includes two resilient members 112 and 114, each with grooves 116, 118 for supporting a spring 120 and elastic material 122 therein. A spring assembly 126, shown in Figure 4d, mounted in a housing 128 for sealing against a shaft 130, includes a resilient member 132 having a flange 134 thereon for recording the seal in the dynamic application. As shown in Figure 4d, a spring 136 is completely surrounded by the elastic material 138 within the groove 140 of the elastic member 132, the elastic material 138, having a solid or hollow (not shown) center. A dynamic seal apparatus 142 is shown in Figure 4e which generally includes a resilient member 144, a spring 146 and the elastic material 148, all disposed within a groove 150 in the housing 152. In another application in Figure 4F, a spring assembly 154 is useful in a syringe 156 application in which the resilient material 158 supports the spring 160 and the elastic material 162 within a groove 163 to lock the resilient member 158 with a fitting 164. Figure 4g, shows a seal apparatus 143 similar to that shown in Figure 4f including a resilient member 145, and a spring 161 for applications involving a very small diameter. While the hereinabove embodiments of the present invention have been described in connection with a canted coil spring, other types of springs such as a round ribbon-type spring 170 may be utilized in a seal 172 with an elastomer, or plastic, 174 as shown in Figure 5. Any number of spring configurations may be utilized, as for example, shown in Figures 6a and b in which a flat U or V-shaped spring 180 with an elastomer 182 disposed therearound. Thereafter, the spring 180 and elastomer 182 may be disposed in any suitable resilient material (not shown) for sealing in accordance with the present invention. While the spring assemblies 10, 40 shown in Figures 1 and 2 have a generally circular shape, it should be appreciated that any irregular shapes, such as the spring assembly 248 shown in Figure 7, may be utilized which includes an elastic material 250 having a solid, or hollow cross section. If the elastic material chosen is supporting, contrasted to a jell-like material, the springs 30, 58 may be filled by any manufacturing method suitable for the elastomer employed, such methods including extrusion, molding, spring or any other suitable method for introducing the elastomer, or plastic, 32, 56 in and around the spring 30, 58, either filling or leaving a hollow cross-section. Various embodiments of the present invention are shown in Figures 8 through 12. In Figure 8, coils 252 with an interior elastomer 254 are shown with the coils 252 having an elliptical shape and the elastomer 254 having a circular shaped void 256 therethrough. Figure 9 shows elliptically shaped coils 256 having an elastomer 258 with an offset, or generally rectangular, hollowed cross-sectional opening 260 therethrough, while Figure 10 shows an elliptically shaped coils 262 having an elastomer 264 with an irregularly shaped opening 266 comprising to generally circular cross-sectional areas 268, 268'. The elastic material may be disposed within the coils 252, 256, 262 as shown in Figures 8, 9 and 10 or, alternatively, as shown in Figure 11, an elastomer 268A may be disposed on one side 270A of coils 272A. This embodiment is most useful in applications in which a greater distribution of the load is desirable n the one side 270A of the coils 272A. Other embodiments 270, 272, 274 of the present invention, shown respectively in Figures 12 through 14, said embodiments 271, 272, 274 including coils 278, 280, 282 and elastomers 286, 288, 290. The embodiment 270 includes an open area 290 through the coils 278 in order to facilitate the passage of fluid (not shown) for pressure variation cooling or lubrication purposes. As can be seen from Figure 13, the elastomer 288 may be disposed as a coating, both the inside 294 and outside 296 of the coil 280, while Figure 14 shows the elastomer 290 disposed along the outside and through the coils 282. All of these embodiments differently affect the force-deflection characteristics of the embodiments 271, 272, 274, depending upon the application of the embodiment 271, 272, 274. The ability to maintain a relatively constant force within a certain deflection is affected by a number of parameters, all of which are taken into consideration, which include the cross-section of the elastomer and the disposition thereon as indicated in Figures 8 through 14, the thickness of the elastomer, the position of the elastomer, or plastic, relative to the coils, the flexibility of the elastomer, the degree of bonding between the coils 252, 256, 262, 270A, 278, 280, 282 and corresponding elastomers 254, 256, 264, 268A, 286, 288, 288A, 290, the spacing between the coils 252, 256, 262, 270A, 278, 280, 282, the wire diameter, coil height and coil width, among other considerations. The various positions of the elastomer, or plastic, relative to the coils is illustrated in the Figures 15a, b and c, showing the coils 292, 294, 296, and respectively, the elastomers 293, 295 and 297. As shown in Figure 15a, the elastomer 293 is in the form of a tube in which the coils 292 are inserted. Alternatively, the elastomer, or plastic material, 293 could be molded or extruded upon the coils 292. In this embodiment the elastomer, or plastic material, 293, does not significantly enter spaces between the coils 292. As shown in Figure 15b, the elastomer 295 partially fills the spaces between the coils 294 so that the elastomer, or plastic, 295 covers the outer portion of the coil 294 and between the coils 294 to a point below the top 299 of the coil. The depth of the elastomer, or plastic, 295 between the coils controls the force developed by the coils 294. Alternatively, as shown in Figure 15c, the elastomer, or plastic, 297, is flush with the outside 299a of the coil 296, but extends partially between the coils 296 and of course around them. In this embodiment, the depth of the elastomer, or plastic, 297 from the surface 299a inwardly between the coils 296 determines the degree of flexibility of the coil. It is to be appreciated that when a canted-coil spring is filled with an elastomer, especially in an outer portion of the coil, the force applied thereon is transmitted more uniformly and the stress acting on the mating parts is substantially lower. It has been unexpectedly found that the combination of the elastic or flexible material 32, 56, with the spring 30 and 56 within the resilient material 12, 42, results in a sealed life substantially longer than when he spring 30, 58 is utilized within the resilient member 12, 42 without the elastic material 32, 56 present. These results occur when the resilient member 12, 42 is formed of elastic-type material such as silicone, plastic, fluorosilicones, PTFE, elastomers, either bonded or not bonded, to the spring 30, 58. In addition, jelly-like materials such as paste and sealants, caulks and greases, waxes, may be utilized. As set forth in U.S. Patent Application Serial No. 496,329, force developed by the spring 30, 58, filled with an elastomer material 32, 56 results in a force which is substantially higher than the spring alone. In this instance, a spring with a smaller diameter may be utilized which permits more coil springs and therefore better distribution of a load. As shown in Figure 4f, embodiments of the present invention used in a locking/holding embodiment 154, the elastomer may further act to reduce possible rotation of the spring 160. In this instance, the spring 160 may be filled with a material that has a high coefficient friction to reduce the possibility of movement. This material may be of polyurethane elastomer which has a high friction or a high temperature plastic such as polyphelene sulfide (POPS), poly-ether ketone (PEEK). A series of tests conducted confirm the increased life of seals 10, 132 utilizing a resilient material 32, 138 comprising PTFE and an elastomer with a hollow cross section formed of Dow Corning RTV 732. The specifications of the test as well as the seal utilized are shown in Tables 1 and 2 for the identical resilient member 12, 132 and spring 30, 136 without elastic material 32, 138 as a control, and with the elastic material present and either bonded to the spring 30, 136 or not bonded with the spring 30,1368. Bonding of the elastic material 32, 138 to the spring 30, 136 may be controlled in any known conventional manner such as by etching the wire spring and priming it prior to application of the elastic material, or not priming the spring and applying a release material so that non-bonding between the elastic material 32, 138 with the springs 30, 136 do not occur. Table 1 shows the test comparison utilizing a reciprocating shaft and the seal 10, while Table 2 shows the results of a rotating test comparison for the seal 10. It can be seen that without change of the resilient member 12 or its sealing surfaces 14, 16 that the internal biasing of the combined spring 30 and elastic material 32 cause the life of the spring to be 2.8 times the life of the spring without the elastomer when the elastomer is bonded to the spring and three and one-half times the life when the elastomer is not bonded to the spring. This increase in life is truly unexpected. Similarly, in the rotating test, the seal 92 with the bonded elastomer spring had a life of 3.1 times the spring elastic member alone and 4.3 times the life of the spring and resilient member alone when the elastomer is not bonded to the spring. Turning to Figure 16a and b, there is an alternate embodiment of a spring assembly 300 which includes a first plurality of coils 302 inter-connected with another in a spaced-apart relationship for causing the spring assembly 300 to exert a generally constant force in a loading direction normal to a tangent to a centerline 304. As hereinbefore described in connection with the plurality of coils 302, an elastic material 306 is disposed around and between the plurality of coils 302 a hollow cross section 308 which provides means for modifying the force exerted by the spring 302 assembly 300 in response to deflection of the spring assembly 300 along a loading direction as hereinbefore described. Disposed within the plurality of coils 302 is a second plurality of coils 310 interconnected with one another in a spaced apart relationship and disposed in a cooperating relationship inside the first plurality of coils for causing the spring assembly 300 to exert a generally constant force in a loading direction approximately normal to the centerline 304. An elastic material 312 disposed around and between the plurality of coils 310 and includes a hollow cross section 314. Figure 16b shows a cross sectional view of the spring assembly 300 and also showing that the elastic materials 306, 312 may be separate from one another with a gap 320 therebetween to allow relative movement therebetween as the spring assembly 300 is loaded. Similar to the spring assembly 300, a spring assembly 330 shown in Figures 17a and b include a first plurality of coils 332 with an elastic material 334 disposed therearound and a second plurality of coils 336 within the elastic material 338 therearound. The configuration of the first and second plurality of coils 332, 336 and elastic material 334, 338 is similar to the coil assembly 300 shown in Figure 16a and b except that the first plurality of coils 332 is canted in an opposite direction from the second plurality of coils 336 along a centerline 342. The performance of the embodiments shown in Figures 16a and b and 17a and b are similar to that hereinbefore described in connection with the spring assembly 10 further extending the design range capability of the forced deflection curves thereof. Although there has been hereinabove described a specific arrangement of a seal apparatus in accordance with the present invention, for the purpose of illustrating the manner in which the invention may be used to advantage, it should be appreciated that the invention is not limited thereto. Accordingly, any and all modifications, variations, or equivalent arrangements which may occur to those skilled in the art, should be considered to be within the scope of the invention as defined in the appended claims. | Seal apparatus having a resilient member (12) with at least one sealing surface (14, 16) thereon and an engagement surface (22), said engagement surface (22) being spaced apart from said sealing surface (14, 16) and a spring (30) disposed in a position biasing said engagement surface (22) characterized by having a flexible or jelly-like material (32) disposed around the spring (30), for increasing a length of time that the sealing surface (14, 16) can effectively block the passage of fluid therepast. The seal apparatus according to claim 1 further characterized in that the engagement surface (22) comprises a groove (20) and the spring (30) is disposed within the groove (20). The seal apparatus according to claim 2 further characterized in that the flexible or jelly-like material (32) is disposed in and around the spring (30) and has a solid cross section. The seal apparatus according to claim 2 further characterized in that the flexible jelly-like material (32) is disposed in and around the spring (30) and has a hollow cross section. The seal apparatus according to claim 3 or 4 further characterized in that the flexible or jelly-like material (32) is bonded to the spring (30) but not bonded to the resilient member (12). The seal apparatus according to claim 3 or 4 further characterized in that the flexible jelly-like material (32) is not bonded to the spring (30) or to the resilient member (12). Seal apparatus having a resilient member (12) with at least one sealing surface (14, 16) thereon and a groove (12) therein, said groove (12) being spaced apart from said sealing surface and a spring assembly (300) disposed within the groove (12), characterized by fact that the spring assembly includes a first plurality of coils (302) interconnected with one another in a spaced-apart relationship, for causing the spring assembly (300) to exert a generally constant force in a loading direction approximately normal to the sealing surface (14, 16) in response to deflection of the spring assembly (300) along said loading direction, a second plurality of coils (310) interconnected with one another in a spaced-apart relationship and disposed within said first plurality of coils (302) and in a cooperating relationship therewith, for causing the spring assembly (300) to exert a generally constant force in a loading direction approximately normal to the sealing surface (14, 16) in response to deflection of the spring assembly (300) along said loading direction, and a flexible or jelly-like material (306) disposed in the groove (12) with the spring assembly (300) for increasing a length of time that the sealing surface can effectively block the passage of fluid therepast when bearing against a surface moving relative thereto. The seal apparatus according to claim 7 further characterized in that the flexible or jelly-like material (306) is disposed in and around the first and second plurality of coils (302, 310) and has a solid cross section. The seal apparatus according to claim 7 further characterized in that the flexible or jelly-like material (306) is disposed in and around the first and second plurality of coils (302, 310) and has a hollow cross section. The seal apparatus according to claim 8 or 9 further characterized by the fact that the flexible or jelly-like material (306) is bonded to at least the first and second plurality of coils (302, 310) not bonded to the resilient member (12). The seal apparatus according to claim 8 or 9 further characterized by the fact that the flexible or jelly-like material (306) is not bonded to either of the first and second plurality of coils (302, 310) or to the resilient member (12). A method for extending the useful life of a seal (10), said seal (10) having at least one sealing surface (14, 16) thereon, comprising the steps of coating a spring (30) with a flexible material or jelly-like material (32) and disposing the coated spring (30) in a spaced-apart relationship with the sealing surface (14, 16) position for biasing the sealing surface (14, 16) against an exterior surface. The method according to claim 12 further characterized in that the flexible or jelly-like material (32) is not bonded to the spring (30). The method according to claim 12 further characterized in that the flexible or jelly-like material (32) is of sufficient thickening to extend the useful life of the seal (10) at least 300 percent. The method according to claims 12, 13, or 14 further characterized in that the flexible or jelly-like material (32) is a silicone elastomer and said seal (10) comprises polytetrafluoroethylene. | BALSELLS JOAN C; BALSELLS PETER J; BALSELLS, JOAN C.; BALSELLS, PETER J. | BALSELLS PETER J; BALSELLS, PETER J. |
EP-0490240-B1 | 490,240 | EP | B1 | EN | 19,990,623 | 1,992 | 20,100,220 | new | H01L27 | H01L21, H01L23, H01L27 | H01L27 | H01L 27/115C | Ferroelectric capacitor and method for forming local interconnection | Problems arise when connecting the bottom plate of a ferroelectric capacitor to the source of its associated access transistor during the fabrication of an ultra large scale integrated memory circuit. The temperature and ambient of certain steps of the fabrication process adversely affects ohmic properties of the connection. To overcome these problems, an insulative layer is formed between the bottom plate of a ferroelectric capacitor and its associated transistor. The insulative layer separates the source from the bottom electrode, and subsequent high temperature swings during the remainder of the fabrication process do not produce any direct connection between the source and the bottom plate. After the memory circuits have been fabricated on the semiconductor wafer, a voltage is applied across the ferroelectric capacitor and the insulative layer, preferably during a wafer probe. The magnitude of the applied voltage is selected to breakdown the insulative layer, but does not damage the ferroelectric layer. As a result, a good ohmic contact is produced between the bottom plate and the source of its associated transistor. | BACKGROUND OF THE INVENTION AND PRIOR ARTThis invention relates generally to semiconductor memories, such as random access memories, and, more particularly, to a memory cell having a ferroelectric capacitor fabricated on a semiconductor wafer and a method for making same.The use of semiconductor memories has grown dramatically since the 1970's. An ideal semiconductor memory would include desirable features such as: low cost per memory cell, high cell density, short access time, random access read and write cycles, low power consumption, nonvolatility, reliable operation over a wide temperature range, and a high degree of radiation hardness. While many types of semiconductor memories exhibit superior characteristics in one or more of these areas, no semiconductor memory is superior in every area.For instance, read only memories (ROMs) are nonvolatile since they retain data even when they are not being powered. However, ROMs are typically preprogrammed and new data cannot be written into them. Programmable ROMs (PROMs) may be programmed by users, but they cannot be erased. A programmable storage cell for a semiconductor integrated circuit (IC) chip is disclosed, for example, in the European Patent Application No. 0224418. The cell is formed from a couple of electrode layers and an insulating layer intervening therebetween and is programmed by applying a voltage between the electrode layers to cause an electrical breakdown and form a conduction path in the insulating layer. The conduction established in the insulating layer by electrical breakdown is assigned to the binary notation 1 for data storage. Binary 0 is characterized by non-conductivity between the electrode layers.Other types of ROMs can be programmed and erased with limited success. For instance, erasable PROMs (EPROMs) may be programmed electronically, but they must be exposed to ultraviolet light to erase the memory cells. Unfortunately, the exposure to the ultraviolet light erases all of the memory cells. The memory cells of an electrically erasable PROM (EEPROM) may be read and written electronically. Unfortunately, these memories are expensive, display a limited read and write endurance, and have relatively slow write access times.Many random access memories (RAMs) are currently available. However, RAMs are volatile, and, thus, depend on external power to maintain the information stored in the memory. Dynamic random access memories (DRAMs), for instance, store information in the form of electrical charges on capacitors. Since each memory cell requires only one transistor and only one capacitor, many memory cells may be fabricated in a relatively small chip area. Static random access memories (SRAMs), on the other hand, utilize a transistor latch having at least two transistors in order to retain information in each memory cell. While SRAMs require little power, they consume a large amount of chip area relative to DRAMs.Although they are volatile, random access memories display many of the previously listed preferred features such as low cost, high density, short access times, and random access read and write cycles. Therefore, computer designers prefer to store as much usable information as possible in RAMs, as opposed to other types of semiconductor memories or disk-type storage devices. As computers have become faster and more complex, the demand for high density RAMs has dramatically increased. Since DRAMs inherently require the smallest cell size, many memory manufacturers have turned their efforts toward packing as many DRAM cells as possible onto a chip.Conventional DRAMs use silicon dioxide capacitors as storage capacitors. However, the limited charge density of the silicon dioxide capacitors prohibits further size reductions. Therefore, complex, three-dimensional processes have been used to maintain the size of the silicon dioxide capacitors while conserving chip area. For instance, a three-dimensional capacitor is formed by folding the capacitor into a trench or by stacking the capacitors to achieve adequate charge storage within an acceptable cell size. Since fabricating three-dimensional capacitors is much more expensive than fabricating planar capacitors, the resulting DRAMs are more expensive.In an effort to overcome these deficiencies, designers have replaced the silicon dioxide capacitors of a conventional DRAM with ferroelectric thin-film capacitors (see H. Bogert, Research Newsletter, Dataquest Inc. 1988).The semiconductor memory cell which is described in the European Patent Application No. 0389762 is non-volatile and employs ferroelectric substances. A ferroelectric film is formed on a diffused layer serving as a source or a drain. An upper electrode is composed mainly of a metal, while the ferroelectric substance film is connected to the high-concentration diffused layer at a contact hole. Formed on the high-concentration diffused layer may be a refractory metal silicide as a lower electrode on which the ferroelectric substance film is then formed.Ferroelectric capacitors display an effective dielectric constant of about 1000 to 1500, as compared to a relatively low dielectric constant of about 4 to 7 for silicon dioxide capacitors. Assuming equal thickness of dielectric layers, the result of this increase in the dielectric constant is that the capacitance of the ferroelectric capacitor is approximately 250 times that of a silicon dioxide capacitor. However, typically the thickness of a ferroelectric dielectric layer is approximately 100-300 nanometers, and the thickness of a silicon dioxide dielectric layer is approximately 10-30 nanometers. Therefore, the capacitance of a typical ferroelectric capacitor is approximately 25-30 times that of a typical silicon dioxide capacitor. As a result, much smaller ferroelectric capacitors may be used in place of the silicon dioxide capacitors. The smaller ferroelectric capacitors can be fabricated using a planar process instead of the three-dimensional process used to manufacture high density silicon dioxide capacitors.In addition to its ability to store a sufficient charge in a smaller area, a ferroelectric capacitor permanently retains charge after application of a voltage. The permanent charge originates from a net ionic displacement within the individual cells of the ferroelectric material. Typically, a ferroelectric cell takes the form of a crystal where atoms within the crystal change position in an electric field and retain this shift even after the electric field is removed. Since electronic circuits can read and write these crystals into one of two permanent states and then sense these states, ferroelectric capacitors are suitable for binary number storage where one crystal state represents a binary one, and the other crystal state represents a binary zero.Many ferroelectric materials exhibit the same atomic structure as a regular perovskite crystal. A unit cell of a perovskite crystal has a general chemical formula of ABO3, where A is a large cation and B is a small cation. A perovskite crystal has a central metallic ion that is displaced into one of two positions along the axis of an applied electric field to create an electric dipole. The central ion remains polarized until an electric field is again applied to reverse it.In a thin-film ferroelectric capacitor, the individual crystals or cells interact to produce domains within the material in response to a voltage being applied across the material. The voltage produces an electric field across the ferroelectric material and causes compensating charge to move through the material to the plates of the capacitor. After the voltage is removed, the majority of the domains remain polarized in the direction of the applied electric field, and compensating charge remains on the plates of the ferroelectric capacitor to maintain the polarization. If a voltage is applied to the ferroelectric capacitor in the same direction as the previously applied voltage, some of the minority of domains, i.e., the remanent domains, polarize in the same direction as the majority of domains. Thus, only a small amount of compensating charge flows onto the capacitor plates. However, if the field is applied in the opposite direction, many domains switch their polarization. Therefore, a greater amount of charge flows onto the capacitor. For a more detailed discussion of ferroelectrics, see L. Cross & K. Hardtl, Encyclopedia of Semiconductor Technology, pp. 234-64, (Grayson, Martin ed. 1985).To form a ferroelectric capacitor as part of an integrated circuit semiconductor chip, a film of ferroelectric material, usually less than a micrometer in thickness, is sandwiched between two metal electrodes. When properly deposited and annealed, the ferroelectric material exhibits the same atomic structure as the previously discussed perovskite crystal. Platinum is typically used for the electrodes, but the choice of the metal depends on the electrical qualities that best compliment the selected ferroelectric material. For instance, the structure of the metal must promote the formation of the proper ferroelectric phase.Deposition of the ferroelectrics must be precisely controlled or the resulting crystal structure will not be uniform. Molecular-beam epitaxy and radio frequency sputtering have been used to apply the ferroelectric material with some success. However, difficulty arises in forming the interconnection between the bottom plate of the ferroelectric capacitor and the diffused region, e.g., the source or the drain, of the access transistor. Once the appropriate material of the capacitor plates is selected, the bottom plate is formed by depositing the metal onto the diffused region of the silicon wafer. The temperature is then raised briefly to about 650° C to ensure that the metal adheres well to the silicon.Next, the ferroelectric material is deposited onto the bottom plate. Typically, the ferroelectric material is deposited at room temperature. Then, the ferroelectric material is annealed in the presence of oxygen by raising the temperature to between 500° and 700° C. At this temperature, the material is in a paraelectric phase, but, as the material cools, it enters the perovskite (ferroelectric) phase and becomes randomly polarized. The presence of oxygen during the anneal is important otherwise the proper ferroelectric phase will not form due to oxygen deficiency in the layer.However, if the bottom plate is made from Platinum or a standard barrier metal, such as TiN, TiW or Ru2O3, it will be adversely affected, particularly in the presence of oxygen, by the high temperatures required to form the perovskite phase in the ferroelectric material. During deposition of the ferroelectric material, the metal of the bottom plate interdiffuses with the diffused region of silicon so that a good ohmic contact, e.g., less than about 100 ohms, cannot be achieved without destroying the integrity of the structure and the switching properties of the ferroelectric capacitor. It is an object of the present invention to overcome or at least minimize the problems encountered in the field of semiconductor IC memories as outlined above.This and other objects are achieved in advantageous manner basically by applying the features laid down in the characterizing parts of the independent apparatus and method claims 1 and 18. Further enhancements are provided by the subclaims.SUMMARY OF THE INVENTIONIn the embodiment there is provided a semiconductor memory cell that includes an access transistor. The drain of the access transistor is connected to an associated bit line, and the gate of the access transistor is connected to an associated word line. The top plate of a ferroelectric storage capacitor is connected to a plate line. An insulative layer is disposed between the source of the access transistor and the bottom plate of the capacitor so that the source is separated from the bottom plate.Preferably, the insulative layer has a first predetermined breakdown voltage, and the layer of ferroelectric material has a second preselected breakdown voltage which is greater than the first preselected breakdown voltage. Typically, this corresponds to the insulative layer being thinner than the ferroelectric layer. Therefore, application of a voltage having a magnitude greater than the first preselected breakdown voltage and less than the second preselected breakdown voltage between the source and the top plate of the capacitor breaks down the layer of insulative material and substantially connects the bottom plate to the source of the access transistor.In accordance with another aspect of the present invention, there is provided a method for fabricating a semiconductor memory cell. First, an access transistor having a source, a drain, and a gate is formed. Second, a layer of insulative material is applied onto the source. Third, a first conductive layer is formed over the insulative layer. Fourth, a layer of ferroelectric material is applied onto the first conductive layer. Fifth, a second conductive layer is formed over the ferroelectric layer.To connect the first conductive layer, i.e., the bottom plate of the ferroelectric capacitor, to the source of the transistor a voltage is delivered between the source and the second conductive layer, i.e., the top plate of the ferroelectric capacitor. The voltage has a magnitude sufficient to breakdown the layer of insulative material and insufficient to breakdown the layer of ferroelectric material.DESCRIPTION OF THE DRAWINGSThe foregoing and other advantages of the invention will become apparent upon reading the following detailed description and upon reference to the drawings in which: Fig. 1 is a schematic illustration of a portion of a dynamic random access memory using ferroelectric capacitors;Fig. 2 illustrates a unit cell of a preferred ferroelectric material in the form of a perovskite crystal in a state that represents a first binary state;Fig. 3 illustrates the unit cell of Fig. 2 in a state that represents a second binary state;Fig. 4 is a graph illustrating a hysteresis curve of a ferroelectric capacitor;Fig. 5 is a cross-sectional view of a dynamic memory cell having a ferroelectric capacitor separated from its associated transistor by a thin insulating layer;Fig. 6 is a schematic illustration of the memory cell illustrated in Fig. 5;Fig. 7 is a cross-sectional illustration of a dynamic memory cell having a ferroelectric capacitor interconnected with its associated transistor; Fig. 8 is a schematic illustration of the memory cell illustrated in Fig. 7;Fig. 9 is an alternate cross-sectional view of a dynamic memory cell having a ferroelectric capacitor separated from its associated transistor by a thin insulating layer; andFig. 10 is another alternate cross-sectional view of a dynamic memory cell having a ferroelectric capacitor separated from its associated transistor by a thin insulating layer.DETAILED DESCRIPTION OF PREFERRED EMBODIMENTSTurning now to the drawings and referring initially to Fig. 1, a ferroelectric random access memory (FERRAM) 10, which is a semiconductor dynamic random access memory using ferroelectric capacitors as storage capacitors, is schematically illustrated. While a memory using ferroelectric capacitors may take a number of forms, the structure and operation of the FERRAM 10 as shown in Fig. 1 will be briefly described so that the reader may attain a better overall understanding of the present invention.Each memory cell 12 or 12' of the FERRAM 10 includes an access transistor 14 or 14' and a ferroelectric storage capacitor 16 or 16'. Preferably, each of the access transistors 14 and 14' are metal-oxide semiconductor field effect transistors, more commonly referred to as MOSFETs. As illustrated, the drain of each of the transistors 14 and 14' is connected to a respective bit line 18 or 18'. The gate of each transistor 14 and 14' is connected to a respective word line 20 or 21. The source of each transistor 14 or 14' is connected to the bottom electrode or plate 22 of its respective ferroelectric capacitor 16 or 16'. The top electrode or plate 24 of each ferroelectric capacitor 16 or 16' is connected to its respective plate line 26 or 27. Preferably, a sense amplifier 28 is connected between each pair of bit lines 18 and 18' in the memory array of the FERRAM 10.To write to the memory cells 12 and 12' that are connected to the word line 20, for instance, a decoder (not shown) selectively produces a logical 1 voltage signal on the word line 20. The high voltage on the word line 20 turns on the access transistors 14 and 14' that are connected to the word line 20. Once turned on, the access transistors 14 and 14' connect the associated ferroelectric storage capacitors 16 and 16' to their respective bit lines 18 and 18'. The sense amplifier 28 drives one bit line 18 to a logical 1 and the other bit line 18' to a logical 0. The plate line 26 is then pulsed to a logical 1. With the plate line 26 at a high voltage and the bit line 18' at a low voltage, the direction of the resulting electric field across the ferroelectric capacitor 16' writes a logical 0 into that capacitor. When the plate line 26 falls back to a logical 0 , the high voltage on the bit line 18 produces an electric field in the opposite direction across the ferroelectric capacitor 16, and, thus, writes a logical 1 onto that capacitor. To read the binary information stored on one of the capacitors 16 or 16', the plate line 26 is again pulsed to a logical 1, the bit lines 18 and 18' are allowed to float, and the sense amplifier 28 is turned off. Since the information stored in the ferroelectric capacitor 16 is opposite the information stored in the other ferroelectric capacitor 16', a voltage differential is produced between the bit lines 18 and 18'. When the sense amplifier 28 turns on, it drives the high going bit line 18 to the positive voltage, e.g., Vdd, and the other bit line 18' to ground. Not only does this operation sense the information stored in one of these selected memory cells 12 and 12', it also restores both ferroelectric capacitors 16 and 16' to their original states (if the plate line 26 is pulsed again to a logical 0 ).Referring additionally to Figs. 2 and 3, a unit cell 30 of the ferroelectric material that comprises the dielectric of the ferroelectric capacitors 16 and 16' is illustrated. Preferably, a ferroelectric material that exhibits a perovskite crystalline structure (chemical formula ABO3) is used, such as lead zircronate titanate (PZT), lanthanum-doped PZT (PLZT), or lithium niobate (LiNbO3). The A atoms 32 are large cations situated at the corners of the unit cell 30, and the oxygen atoms 34 are situated at the face centers of the unit cell 30. The B atom 36 is a small cation that is located near the center of the unit cell 30 and bonded to the six oxygen atoms 34. In PZT, the A atoms 32 are lead and the B atom 36 is titanium or zirconium.The B atom 36 may be displaced into one of two positions along the axis of an applied electric field to create an electric dipole. This polarization is relatively permanent until another electric field reverses it. For example, if an electric field is applied to the unit cell 30 in the direction of arrow 38, the B atom 36 is displaced upwardly, as illustrated in Fig. 2. Alternatively, when an electric field is applied across the unit cell 30 in the direction of the arrow 40, the B atom 36 is displaced downwardly, as illustrated in Fig. 3.A ferroelectric thin-film memory capacitor 16 and 16' exhibits a characteristic hysteresis curve which describes the amount of charge the device stores as a function of the applied voltage. A typical hysteresis curve is illustrated in Fig. 4 as a function of charge density versus applied voltage. The coercive voltages Vc and -Vc represent the digital switching threshold of the capacitor 16 and 16'. For memory applications, it is desirable that the two coercive voltage points Vc and -Vc be symmetrical about zero volts between -2.5 volts and +2.5 volts, so that the memory can operate from standard semiconductor memory power supply voltages, which are typically -5 volts to +5 volts. Typically, the switched charge of a ferroelectric capacitor 16 and 16' is greater than 20 microcoulombs per square centimeter, which is an order of magnitude higher than the 1.7 microcoulombs per square centimeter that is typical of current DRAM capacitors. For a PZT thin film capacitor, the typical switching threshold is about 1 to 2 volts, so it is compatible with a 5 volt power supply. Nonvolatile operation results from stable polarization states X and Y that exist at the top and bottom of the loops, respectively.The permanent charge storage of a ferroelectric capacitor 16 results from a net ionic displacement of the unit cells in the ferroelectric capacitor material that results from the application of voltage across the ferroelectric capacitor 16 or 16'. When voltage is applied across a ferroelectric capacitor 16 or 16', the individual unit cells 30 constructively interact to produce polarized domains within the material. After the voltage is removed, the majority of the domains remain polarized in the direction of the applied electric field, as previously described in regard to Figs. 2 and 3. Therefore, compensating charge remains on the plates of the capacitor 16 to maintain this polarization.When the polarization of a ferroelectric capacitor 16 switches, the switched charge represents the majority of the unit cells 30 that switch in response to an applied voltage, and the unswitched charge represents the remaining unit cells 30 that do not switch in response to the applied voltage. For example, if the capacitor 16 is in the stable polarization state Y(0) and a positive voltage greater than the coercive voltage is impressed across the capacitor 16, then the capacitor conducts current along curve 42 and the charge density increases to point Y(1). When the voltage returns to zero, the charge density decreases slightly along curve 44 to point X(0). If another positive voltage is impressed across the capacitor 16, the charge density changes little since there is little unswitched charge. However, if a negative voltage greater than the negative coercive voltage is impressed across the capacitor 16, current flows through the capacitor 16 and the charge density decreases to point X(1). When the negative voltage returns to zero, the charge density increases slightly along curve 42 to point Y(0).When the plate line 26 or 27 is pulsed to read the contents of a memory cell 12 or 12', the change in charge on the bit lines 18 and 18' depends on the previous state of polarization of the ferroelectric capacitor 16 or 16'. As previously described with respect to Fig. 1, to read information stored in a ferroelectric capacitor 16, a positive voltage pulse having a magnitude greater than the coercive voltage is applied. If little current flows through the capacitor 16 then the capacitor is in state X(0), which may correspond to a binary one. On the other hand, if a substantial amount of current flows through the capacitor 16 then the capacitor was in state Y(0), which may correspond to a binary zero. Thus, after even extended periods without power, the ferroelectric capacitors 16 and 16' can be pulsed to determine the last logical state stored in the capacitor 16 or 16'. Therefore, not only do the ferroelectric capacitors 16 and 16' provide increased charge density to allow the use of smaller capacitors in ultra large scale integration memory circuits, but they also provide nonvolatile charge storage.The surface of a typical integrated circuit memory is a maze of p-type and n-type regions that must be contacted and interconnected. It is important that such contacts and interconnections be ohmic, with minimal resistance and no tendency to rectify signals. During the metallization step in the fabrication process, the various regions of each circuit element are contacted and proper interconnection of the circuit elements is made. Aluminum is commonly used for metallization since it adheres well to silicon and to silicon dioxide if the temperature is raised briefly to about 400° to 450° C after deposition. However, platinum is the best choice of the bottom electrode for a ferroelectric capacitor, because platinum allows good crystal growth for the PZT ferroelectric material. Unfortunately, platinum forms a Schottky barrier when applied to a silicon semiconductor, and tends to rectify signals passing across the metal-semiconductor junction.Referring now to Fig. 5, a cross-sectional view of a memory cell 12 is illustrated. For an n-channel MOSFET, a p-type silicon wafer 50 is used. To fabricate the access transistor 14, an oxide layer 51 is grown on the p-type wafer 50 and polysilicon 53 is deposited thereon. Portions of the oxide 51 and polysilicon 53 are etched away, and the source 52 and the drain 54 of the transistor 14 are formed by diffusing an impurity in column V of the periodic table, such as phosphorus, arsenic or antimony, into the exposed portions of the wafer 50. Silicon dioxide is again deposited onto the wafer 50, and windows for the contact holes 56 and 58 are masked and etched.To fabricate the ferroelectric capacitor 16 or 16', a layer of an insulative material 60 is deposited in the contact hole 56 on the source 52. Preferably, the insulative layer 60 is either silicon dioxide (SiO2), a nitride layer (SiN), or an amorphous silicon layer. Any appropriate deposition method may be used, such as thermal growth or CVD deposition. Preferably, the thickness of the insulative layer 60 is approximately 100 angstroms (10 nanometers).A conductive layer, which forms the bottom plate 22, is deposited on top of the insulative layer 60. Preferably, the bottom plate 22 is platinum and deposited by sputtering. The ambient temperature is briefly raised to about 650°C to insure proper adhesion between the bottom plate 22 and the source 52.Next, a thin film 62 of the ferroelectric material is deposited or grown on the bottom electrode 22. Preferably, the ferroelectric material is PZT and deposited using sol-gel processing or radio frequency sputtering. Advantageously, the thickness of the ferroelectric film 62 is at least an order of magnitude greater than the thickness of the insulative layer 60. For example, if the thickness of the insulative layer 60 is approximately 100 angstroms, the thickness of the ferroelectric film is approximately 1000 to 2000 angstroms. The ferroelectric film 62 is deposited at room temperature. Then, the ferroelectric film is annealed at a relatively high temperature of approximately 500° to 700° C, and then cooled so that the unit cells form perovskite crystals. However, this high temperature does not cause the bottom plate 22 to interdiffuse with the silicon source 52 because the insulative material 60 is disposed therebetween.The top plate 24 is then deposited onto the ferroelectric layer 62 in much the same manner as the bottom electrode 22 was deposited onto the insulative layer 60. Again, the ambient temperature is briefly raised to about 650°C. This annealing step insures proper phase formation of the ferroelectric material and proper adhesion between the top plate 24 and the ferroelectric film 62.After processing is completed and before forming the local interconnect between the bottom electrode 22 and the source 52, the structure of the memory cell 12 resembles that described in Fig. 5. Fig. 6 illustrates the equivalent circuit of the memory cell 12 before the local interconnect is formed. The insulative layer 60, which is disposed between the source 52 of the access transistor 14 and the bottom plate 22, electrically appears as a capacitor 70 in series with the ferroelectric capacitor 16. Although the areas of the capacitors 22 and 70 are substantially equal, the thicknesses of the two layers 60 and 62 are approximately 20 to 1: approximately 2,000 angstroms for the ferroelectric layer 62 and approximately 100 angstroms for the insulative layer 60. The dielectric constants are about 250 to 1: approximately 1,000 for the ferroelectric capacitor 16 and approximately 4 for the series capacitor 70. Therefore, the capacitance of the ferroelectric capacitor 16 is approximately twelve times that of the capacitance of the series capacitor 70.Given the different capacitances, when a voltage is applied across the series combination of the capacitor 70 and the capacitor 16, less than 10% of the voltage will drop across the capacitor 16. To form the interconnect between the bottom plate 22 and the source 52, a predetermined voltage is applied across the capacitor 70 and the ferroelectric capacitor 16. The predetermined voltage should be sufficient to exceed the breakdown voltage of the insulative layer 60 in the capacitor 70 without damaging the ferroelectric layer 62 in the capacitor 16. Preferably, the interconnection is formed during a wafer probe, which is a functional testing of the memory device in wafer form, by applying the predetermined voltage to the bit lines 18 and 18' while the appropriate word lines are at a logical 1. Alternatively, the interconnect may be formed by applying the predetermined voltage to many capacitors by operating the memory in a parallel mode where several bit and word lines are activated at once.Fig. 7 illustrates a cross-sectional view of a memory cell 12 after the local interconnect has been formed between the bottom plate 22 of the ferroelectric capacitor 16 and the source 52 of the access transistor 14. Fig. 8 illustrates an equivalent circuit diagram of a memory cell 12 after the local interconnect has been formed. Since the insulative layer 60 has been effectively destroyed by the application of the predetermined voltage in excess of its breakdown voltage, Fig. 7 shows the bottom plate 22 as being interconnected with the source region 52. The destroyed insulative layer 60 provides an ohmic contact between the bottom plate 22 and the source 52. This small resistance is illustrated in Fig. 8 as a resistor 72 that is connected in series between the source 52 of the access transistor 14 and the bottom plate 22 of the ferroelectric capacitor 16. The value of the resistor 72 is typically only a few ohms, and certainly less than 100 ohms. Specifically, the value of the resistor 22 will not adversely impact the performance of the memory cell 12. Since there are no high temperature steps required after the formation of the local interconnect by the application of the predetermined voltage, the interconnection between the bottom plate 22 and the silicon source 52 will be highly reliable.The previously described method for forming a ferroelectric capacitor can also be utilized where the ferroelectric capacitor is formed directly on a polysilicon line. Referring now to Fig. 9, an alternate cross-sectional view of the memory cell 12 is illustrated. For an n-channel MOSFET, a p-type silicon wafer 80 is used. To fabricate the access transistor 14, an oxide layer is grown on the p-type wafer 80 and polysilicon is deposited thereon. Portions of the oxide and polysilicon are etched away to leave a polysilicon gate 82. The polysilicon gate 82 also functions as the word line 20. The source 84 and the drain 86 of the transistor 14 are formed by diffusing an impurity in column V of the periodic table, such as phosphorus, arsenic or antimony, into the exposed portions of the wafer 80.Silicon dioxide 88 is again deposited onto the wafer 80, and windows for the contact holes 90 and 92 are masked and etched. A layer of polysilicon 94 is deposited over a portion of the oxide layer 88 and over the contact hole 92. The polysilicon layer 94 forms the bit line 18. A layer of silicon dioxide 96 is deposited over the polysilicon line 94 as an insulative layer. Again, the contact hole 90 is etched, and a layer of polysilicon 98 is deposited over the contact hole 90. The layer of polysilicon 98 will form the connection between the source 84 of the access transistor 14 and the bottom electrode 22 of the storage capacitor 16.To fabricate the ferroelectric capacitor 16 or 16', a layer of an insulative material 100 is deposited onto the polysilicon layer 98. Preferably, the insulative layer 100 is either silicon dioxide (SiO2), a nitride layer (SiN), or an amorphous silicon layer. Any appropriate deposition method may be used, such as thermal growth or CVD deposition. Preferably, the thickness of the insulative layer 100 is approximately 100 angstroms (10 nanometers).A conductive layer 102, which forms the bottom plate 22, is deposited on top of the insulative layer 100. Preferably, the bottom plate 22 is platinum and deposited by sputtering. The ambient temperature is briefly raised to about 650°C to insure proper adhesion between the bottom plate 22 and the insulative layer 100.Next, a thin film 104 of the ferroelectric material is deposited or grown on the bottom electrode 22. Preferably, the ferroelectric material is PZT and deposited using sol-gel processing or radio frequency sputtering. Advantageously, the thickness of the ferroelectric film 104 is at least an order of magnitude greater than the thickness of the insulative layer 100, as described in reference to Fig. 5. The ferroelectric film 104 is deposited at room temperature. Then, the ferroelectric film 104 is annealed at a relatively high temperature of approximately 500° to 700° C, and then cooled so that the unit cells form perovskite crystals. However, this high temperature does not cause the bottom plate 22 to interdiffuse with the polysilicon layer 98 because the insulative material 100 is disposed therebetween.A second conductive layer 106, which forms the top plate 24 of the storage capacitor 16, is then deposited onto the ferroelectric layer 104 in much the same manner as the bottom electrode 22 was deposited onto the insulative layer 100. Again, the ambient temperature is briefly raised to about 650°C. This annealing step insures proper phase formation of the ferroelectric material and proper adhesion between the top plate 24 and the ferroelectric layer 104.Optionally, a second insulative layer 108 may be deposited over the top plate 24. Then, a final layer of polysilicon 110 is deposited over the entire memory cell. The polysilicon layer 110 connects the top plate 24 to the plate line 26.After processing is completed and before forming the local interconnect between the bottom electrode 22 and the polysilicon layer 98, the equivalent circuit of the memory cell 12 is the same as that illustrated in Fig. 6. The insulative layer 100, which is disposed between the polysilicon layer 98 and the bottom plate 22, electrically appears as a capacitor 70 in series with the ferroelectric capacitor 16. Although the areas of the capacitors 22 and 70 are substantially equal, the thicknesses of the two layers 104 and 100 are approximately 20 to 1: approximately 2,000 angstroms for the ferroelectric layer 104 and approximately 100 angstroms for the insulative layer 100. Therefore, when a predetermined voltage is applied across the capacitor 16, as previously discussed, the insulative layer 100 (and the insulative layer 108, if present) will breakdown. Thus, the bottom plate 22 becomes interconnected with the polysilicon layer 98 which is connected to the source region 84.This method for forming a ferroelectric capacitor can also be utilized where the ferroelectric capacitor is formed as a stacked capacitor in a memory cell 12 having a diffused bit line. Referring now to Fig. 10, another alternate cross-sectional view of the memory cell 12 is illustrated. For an n-channel MOSFET, a p-type silicon wafer 120 is used. To fabricate the access transistor 14, a gate oxide layer 122 is grown on the p-type wafer 120 and polysilicon is deposited thereon. Portions of the oxide and polysilicon are etched away to leave a polysilicon gate 124. The polysilicon gate 124 also functions as the word line 20. The source 126 and the drain 128 of the transistor 14 are formed by diffusing an impurity in column V of the periodic table, such as phosphorus, arsenic or antimony, into the exposed portions of the wafer 120.In this memory cell configuration, the drain 128 of the transistor 14 functions as the diffused bit line 18. Therefore, an intermediate layer of silicon dioxide 130 is deposited onto the wafer 120, and a single window for the contact hole 130 is masked and etched. Polysilicon 132 is then deposited over the contact hole 130. The polysilicon 132 will form the local interconnect between the source 126 and the bottom plate 22.Using a series of masking and etching steps, the ferroelectric capacitor 16 is formed. A layer of an insulative material 134 is deposited onto the polysilicon 132. Preferably, the insulative layer 134 is either silicon dioxide (SiO2), a nitride layer (SiN), or an amorphous silicon layer. Any appropriate deposition method may be used, such as thermal growth or CVD deposition. Preferably, the thickness of the insulative layer 134 is approximately 100 angstroms (10 nanometers).A conductive layer 136, which forms the bottom plate 22, is deposited on top of the insulative layer 134. Preferably, the bottom plate 22 is platinum and deposited by sputtering. The ambient temperature is briefly raised to about 650°C to insure proper adhesion between the bottom plate 22 and the insulative layer 134.Next, a thin film 138 of ferroelectric material is deposited or grown on the bottom plate 22. Advantageously, the thickness of the ferroelectric film 138 is at least an order of magnitude greater than the thickness of the insulative layer 134, as described in reference to Figs. 5 and 9. The ferroelectric film 138 is deposited at room temperature, and, then, annealed at a relatively high temperature of approximately 500° to 700° C. Upon cooling the unit cells of the ferroelectric material form perovskite crystals. However, this high temperature does not cause the bottom plate 22 to interdiffuse with the polysilicon 132 because the insulative material 134 is disposed therebetween.A second conductive layer 140, which forms the top plate 24 of the storage capacitor 16, is then deposited onto the ferroelectric layer 138 in much the same manner as the first conductive layer 136, which forms the bottom electrode 22, was deposited onto the insulative layer 134. Again, the ambient temperature is briefly raised to about 650°C. This annealing step insures proper phase formation of the ferroelectric material and proper adhesion between the top plate 24 and the ferroelectric layer 138.After processing is completed and before forming the local interconnect between the bottom electrode 22 and the polysilicon 132, the equivalent circuit of the memory cell 12 is the same as that illustrated in Fig. 6. The insulative layer 134, which is disposed between the polysilicon 132 and the bottom plate 22, electrically appears as a capacitor 70 in series with the ferroelectric capacitor 16. Although the areas of the capacitors 22 and 70 are substantially equal, the thicknesses of the two layers 138 and 134 are approximately 20 to 1: approximately 2,000 angstroms for the ferroelectric layer 138 and approximately 100 angstroms for the insulative layer 134. Therefore, when a predetermined voltage is applied across the capacitor 16, as previously discussed, the insulative layer 134 will breakdown. Thus, the bottom plate 22 becomes interconnected with the polysilicon 132 which is connected to the source region 126.While the present invention was described with reference to a dynamic random access memory using n-channel field effect transistors, it should be readily apparent that the ultra large scale integration of other types of semiconductor circuits using other types of transistors may benefit by the method for forming a ferroelectric capacitor disclosed herein. | Semiconductor memory cell comprising a transistor (14) having diffused source and drain regions (52, 54) and a gate electrode (53); a ferroelectric storage capacitor (16) comprising a layer of ferroelectric material (62) between a bottom electrode (22) and a top electrode (24); a bit line (18) connected to one of said diffused regions (54); a word line (20) connected to said gate electrode (53); and a plate line (26) connected to said capacitor top electrode (24), the other of said diffused regions (52) being coupled to the bottom electrode (22) of said ferroelectric storage capacitor; and an insulative layer (60) disposed between said other diffused region (52) and said bottom electrode (22), characterized in that the coupling of said other diffused region (52) with said capacitor bottom electrode (22) is in the form of a breakdown conduction path in an insulative layer (60), said insulative layer (60) separating, with the exception of a breakdown conduction path, said diffused region (52) from said bottom electrode (22).The memory cell of claim 1, characterized in that said insulative layer (60) has a first predetermined breakdown voltage, and said layer of ferroelectric material (62) has a second predetermined breakdown voltage being greater than said first voltage.The memory cell of claims 1 or 2, characterized in that said insulative layer (60) has a first preselected thickness, and said layer of ferroelectric material (62) has a second preselected thickness being greater than said first thickness.The memory cell of claim 3, characterized in that said first preselected thickness corresponds to a first predetermined breakdown voltage, and said second preselected thickness corresponds to a second predetermined breakdown voltage being greater than said first voltage.The memory cell of claim 3, wherein said second preselected thickness is in the range of 5 to 50 times thicker than said first preselected thickness.The memory cell of claim 5, wherein said first preselected thickness is about 10 nm (100 angstroms) and said second preselected thickness is about 200 nm (2000 angstroms).The memory cell of claim 1, characterized in that the material of said insulative layer (60) has a first dielectric constant, and said ferroelectric material (62) has a second dielectric constant being greater than said first dielectric constant.The memory cell of claim 7, wherein said second dielectric constant is at least by two orders of magnitude greater than said first dielectric constant.The memory cell of claim 8, wherein said first dielectric constant is about 4, and said second dielectric constant is about 1000. The memory cell of claim 1, characterized in that the material for said ferroelectric layer (62) is selected from a group consisting of lead zircronate titanate, lanthanum-doped lead zircronate titanate, or lithium niobate.The memory cell of claim 1 or 2, characterized in that said insulative layer (60) provides an ohmic contact between said diffused region (52) and said bottom electrode (22) in response to a predetermined voltage being delivered across said insulative layer (60).The memory cell of claim 11, characterized in that said insulative layer (60) is adapted for breaking down to provide a local interconnect from said bottom electrode (22) to said source electrode (52) in response to an application of a voltage being a magnitude greater than said first predetermined breakdown voltage and less than said second predetermined breakdown voltage.The memory cell of claim 1, characterized in that said transistor (14) is a MOSFET access transistor.The memory cell of claims 1 and 12, characterized in that the relative thicknesses of said ferroelectric layer (62) and of said insulative layer (60) are determined in such a manner that breakdown of only said insulative layer (60) is effected in response to a voltage of predetermined magnitude applied between said plate line (26) and said bit line (18).The memory cell of claim 1, characterized in that a polysilicon layer (98) is disposed on said diffused region (84 in Fig. 9) and that said insulative layer (100 in Fig. 9) is disposed between said polysilicon layer (98) and said bottom electrode (102 in Fig. 9), said insulative layer (100) separating said polysilicon layer (98) from said bottom electrode (102).The memory cell of claim 15, characterized in that said insulative layer (100) is adapted to provide an ohmic contact between said polysilicon layer (98) and said bottom electrode (102) in response to a predetermined voltage being delivered across said insulative layer (100).The memory cell of claim 15, wherein said polysilicon layer (98) is disposed on said source electrode (84 in Fig. 9) and said layer of insulative material (100) is disposed between said polysilicon layer (98) and said bottom electrode (102) of said ferroelectric storage capacitor (16).A method of fabricating a memory cell on a semiconductor wafer, said memory cell comprising a transistor (14) and a ferroelectric storage capacitor (16) and associated bit, word and plate lines (18, 20, 26), with one transistor electrode (52) coupled to the bottom electrode (22) of said ferroelectric storage capacitor, said method including the steps of: forming said transistor (14) by depositing silicon dioxide onto a semiconductor wafer (50);removing selected portions of said silicon dioxide to uncover selected portions of said semiconductor wafer (50); diffusing impurities into said uncovered selected portions of said semiconductor wafer (50) to form a source (52) and a drain (54) of a transistor;depositing a first conductive layer (22) on top of said source (52);applying a layer of ferroelectric material (62) on top of said first conductive layer (22);depositing a second conductive layer (24) on top of said ferroelectric layer (62), said first conductive layer (22), said ferroelectric layer (62) and said second conductive layer (24) forming said ferroelectric capacitor (16) with its bottom and top electrodes (22, 24); said method being characterized by the following additional steps: applying a layer of insulative material (60) between said source (52) and said first conductive layer (22), wherein the coupling between said source (52) and said first conductive layer (22) is in the form of a breakdown conduction path in said insulative layer (60), said breakdown conduction path being achieved bydelivering a voltage between said source (52) and said second conductive layer (24), said voltage having a magnitude sufficient to breakdown said layer of insulative material (60) and insufficient to breakdown said layer of ferroelectric material (62).The method of claim 18, characterized in that said layer of insulative material (60) is deposited onto said source (52) with a first preselected thickness and said layer of ferroelectric material (62) is deposited onto said first conductive layer (22) with a second preselected thickness which is greater than said first preselected thickness.The method of claim 18, characterized in that said layer of insulative material (60) has a first predetermined breakdown voltage and said layer of ferroelectric material (62) has a second predetermined breakdown voltage which is greater than said first predetermined breakdown voltage. The method of claim 20, characterized in that in said voltage delivering step, a voltage is delivered between said source (52) and said second conductive layer (24) having a magnitude greater than said first predetermined breakdown voltage and less than said second predetermined breakdown voltage.The method of claim 18, characterized in that said insulative layer (60) applied onto said source (52) has a first preselected thickness corresponding to a first predetermined breakdown voltage, and said ferroelectric layer (62) applied onto said first conductive layer (22) has a second preselected thickness corresponding to a second predetermined breakdown voltage which is greater than said first predetermined breakdown voltage.The method of claim 18, characterized in that before applying said layer of insulative material (60) onto said source (52), a layer of polysilicon (98) is deposited onto said source (84). | MICRON TECHNOLOGY INC; MICRON TECHNOLOGY, INC. | GNADINGER ALFRED P; GNADINGER, ALFRED P. |
EP-0490241-B1 | 490,241 | EP | B1 | EN | 19,950,614 | 1,992 | 20,100,220 | new | B41J11 | null | G06Q40, B41J11, B41J13, G07D9 | B41J 11/36 | Passbook or the like handling apparatus | The present invention relates to a passbook or the like handling apparatus. According to the present invention, a passbook or the like (6) is scanned by a sensor (5) in a direction perpendicular to printed lines thereof, a nonprinted line is detected in a locus of scanning, and the uppermost line thereof is recognized tentatively as a first nonprinted line. Then, the sensor (5) is made to scan in a direction parallel to the printed lines in order to confirm whether the tentative first nonprinted line is a real nonprinted line or not. | BACKGROUND OF THE INVENTIONThe present invention relates to a passbook or the like handling apparatus, and more particularly to an apparatus which detects a first nonprinted line, which is a line where contents of following transaction are to be printed, with certainty in a passbook or the like. In an apparatus of this type connected with a host computer in which all the contents of past transactions are preserved, the position of a first nonprinted line can be specified easily from data stored in the host computer. Thus, a passbook handling apparatus which becomes an object of the present invention is such a type of apparatus that those data are not stored, but the first nonprinted line is detected every time an account is kept with a bank or a passbook or the like is inserted into the apparatus and unentered contents of the transaction are printed therefrom. In a conventional apparatus of this type, a first line of nonprinted lines has been retrieved by scanning in a vertical direction with respect to printed lines of a passbook or the like using a single optical sensor. JP-A-2-235780 may be mentioned as a citation showing an apparatus having such a structure. Further, techniques for having an optical sensor perform scanning for the purpose of reading bar codes have been disclosed in JP-A-62-46037. SUMMARY OF THE INVENTIONIt is an object of the present invention to provide a passbook or the like handling apparatus which detects a first nonprinted line with certainty. It is another object of the present invention to provide a passbook or the like handling apparatus which detects a first nonprinted line at a high speed and with certainty. It is still another object of the present invention to provide the apparatus described above while restraining increase in number of components as small as possible, in other words, at a low manufacturing cost. According to the present invention, such a configuration is assumed in order to achieve at least one of above-described objects. First, a sensor is made to scan in a direction perpendicular to printed lines. With this, the first nonprinted line can be specified tentatively, but the certainty thereof is the same as that of prior art. In the present invention, after a first nonprinted line is determined temporarily by scanning in the perpendicular direction, the sensor is made to scan in a printing direction, i.e., in a horizontal direction with respect to that line in order to increase the certainty. Furthermore, the sensor is made to scan that line and lines above and under that line. Since the sensor is made to scan in two directions described above, there is a possibility of decrease in the speed of detecting the first nonprinted line. Accordingly, reduction in detection speed is prevented in the present invention by performing scanning in the horizontal direction in a special sequence. Further, in the present invention, an exclusive driver for moving the sensor is omitted by installing the sensor on a printing head which moves evidently both in a horizontal direction and in a perpendicular direction with respect to the printed lines. BRIEF DESCRIPTION OF THE DRAWINGSFig. 1 is a sectional view for explaining a configuration of an embodiment of an apparatus according to the present invention; Fig. 2 is a sectional view of a portion taken along a line II-II in Fig. 1; Fig. 3 is an explanatory diagram of a configuration of an apparatus of an embodiment; Fig. 4 is an explanatory view showing positions and directions of scanning with respect to a passbook; Fig. 5 is a flow chart for explaining one operation of an apparatus shown in Figs. 2 and 3; Fig. 6 is a flow chart for explaining another operation of the apparatus shown in Figs. 2 and 3; Fig. 7 is a flow chart for explaining still another operation of the apparatus shown in Figs. 2 and 3; and Figs. 8A and 8B are flow charts for explaining another operation of the apparatus shown in Figs. 2 and 3. DESCRIPTION OF THE PREFERRED EMBODIMENTSThe present invention will be described in more detail hereinafter with reference to embodiments shown in the accompanying drawings. Fig. 1 is a sectional view showing an embodiment of a passbook handling apparatus according to the present invention, Fig. 2 is a sectional view of a portion taken along a line II-II of the embodiment shown in Fig. 1, and Fig. 3 is an explanatory diagram for explaining the configuration thereof. As shown in Fig. 1 and Fig. 2, the passbook handling apparatus of the embodiment comprises a control section 1, conveyance rollers 2 which convey a passbook 6, a printing head 3 for printing on the passbook 6, a platen 4 and an optical sensor 5 for detecting printed lines. A reference numeral 7 denotes a driver of the printing head 3. Here, the optical sensor 5 is installed on a carrier (not shown) coupled with the printing head 3. Further, the optical sensor 5 is connected with the control section 1 through a cable. In the embodiment shown in Fig. 1 and Fig. 2, retrieval in a direction perpendicular to printed lines is performed by conveying the passbook 6 by means of conveyance roller 2 in a state that the printing head 3 has been brought to a standstill at a predetermined position. Further, by moving the printing head 3 in a state that the passbook 6 has been brought to a standstill at a predetermined position, the optical sensor 5 provided on a carrier which is movable synchronously with the printing head 3 moves in the horizontal direction with respect to the printed line, thus performing retrieval in the horizontal direction with respect to the printed line. Retrieval in a perpendicular direction and retrieval in a horizontal direction with respect to the passbook 6 will be described in more detail with reference to Fig. 4 and Fig. 5. When the passbook 6 is inserted into the passbook handling apparatus, the optical sensor 5 is positioned at a position of a date column of the passbook 6 in the first place. Then, the optical sensor 5 scans in a direction shown with an arrow mark a, i.e., in a direciton perpendicular to the printed lines with the rotation of the conveyance rollers 2. The control section 1 determines whether the data column of the relevant line has been printed or not with the output data of the optical sensor 5 at that time. It is assumed that it has been retrieved with the foregoing that printing has been made up to the fourth line and the fifth line and thereafter are nonprinted lines. In the next place, the printing head 3 is moved in a horizontal direction (a direction shown with an arrow mark b or c) for scanning in a state that the printing head 3 is positioned at the fifth line (i.e., in a state that the optical sensor 5 in positioned at the fifth line). With this, the control section 1 determines whether the fifth line is a printed line or not. Fig. 4 is a flow chart showing above-described operation. Namely, the sensor 5 is made to scan relatively in a perpendicular direction with respect to printed lines in a step 51, thereby to determine whether printing has been made or not in every line (step 52). With this, scanning is performed with respect to a certain page of the passbook from an upper edge thereof in due succession, i.e., from the top to the bottom of that page in order. Then, when a line including no printing (a first nonprinted line) is detected, that line is scanned in a horizontal direction (step 53). When the line includes some printings, error indication is made on a display not shown so as to solicit a user to go over to the window (steps 54 and 56). In case no printing is included in the line, the line is confirmed and recognized as the first nonprinted line (F.N.P.L., step 55). Then, the printing head 3 is positioned above the first nonprinted line (step 57). In this case, however, the printing head 3 is located above that line (the fifth line) from the first. Therefore, the head 3 is only to be moved to the left end of that line by driving the driver 7. All of above-described operation is executed by a CPU 1 based on a program stored in a memory. In the above description, the first nonprinted line has been retrieved by scanning in a perpendicular direction, and scanning has been performed next in a horizontal direction with respect to the retrieved nonprinted line so as to confirm that the relevant line is surely a nonprinted line. However, the present invention is not limited thereto, but it may also be arranged, for example, so that scanning in a horizontal direction is performed with respect to the first nonprinted line retrieved by scanning in a perpendicular direction and a plurality of lines above and under the first nonprinted line so as to retrieve printed lines. Fig. 6 is a flow chart showing an example in which printed lines are retrieved by means of above-described scanning in the horizontal direction over a plurality of lines. Steps 60 and 61 in this flow chart are substantially equal to the flow chart shown in Fig. 5. In a step 62, to say nothing of the line determined to be NO (a line recognized tentatively as a first nonprinted line), lines above and under that line are scanned in the horizontal direction. Then, only when no printing is included in the line determined to be NO and the line thereunder and printing is included in a line thereabove, the line determined to be NO is confirmed as the first nonprinted line (steps 63 to 66). In other cases, error indication is shown (step 67). In a step 68, the printing head 63 is positioned above the first nonprinted line which has been confirmed in the step 66. When scanning is executed as shown in Fig. 6, the first nonprinted line can be detected more surely. Fig. 7 shows another sequence of scanning. In a step 701, it is determined first whether printing has been made in the data column in the first line or not. In case no printing has been made, the first line is scanned in the horizontal direction (step 703). When printing is detected, error indication is shown (steps 705 and 707), and when no printing is detected, the first line is confirmed as the first nonprinted line (step 709). Besides, since the printing head 3 is located above the first line at that time, printing can be executed as it stands. When it is determined in the step 701 that no printing has been made in the first line, the sensor is moved perpendicularly up to the 24th line so as to determine in a step 711 whether printing has been made therein or not. When printing is detected, page turning is directed (step 213). When no printing is detected, the 24th line is scanned in the horizontal direction for the purpose of confirmation (step 715). When printing is detected there, error indication is shown (steps 717 and 719). If it is confirmed that no printing has been made, the processing is shifted to a step 721. In the step 721, it is detected whether printing has been made in the 12th line (the central line) or not. When printing has been made, the flow chart shown in Fig. 6 is executed from the 13th line in a step 723. In case no printing is detected in the step 721, the 12th line is scanned in the horizontal direction for the sake of confirmation (step 725). When printing is detected there, error indication is shown (steps 727 and 719). If it is confirmed that no printing is included, the flow chart shown in Fig. 6 is executed from the second line in a step 729. According to the flow chart shown in Fig. 7, determination of existence of a printed line in the relevant page, the fact that up to which line in the relevant page have been printed and so on can be made quickly by having the optical sensor 5 scan only in the horizontal direction in such a selective sequence that the first line, the 24th line (the last line), the 12th line and the 13th line with respect to printed lines in the passbook 6. Besides, the flow chart shown in Fig.7 shows how to retrieve printed lines (the first nonprinted line). However, by retrieving whether the relevant page includes a printed line (or a nonprinted line) or not for instance, it is also possible to check if the passbook has been inserted into the passbook or the like handling apparatus with a wrong page opened instead of inserting it to the passbook or the like handling apparatus with a page corresponding to the transaction opened. In this case, it is a matter of course that the operation can be realized in steps of procedures which are simpler than those in the flow chart shown. Further, scanning in both the perpendicular direction and the horizontal direction has been performed with a single optical sensor in the above-described embodiment, but it is needless to say that scanning may be performed by using two optical sensors. Figs. 8A and 8B show another embodiment of the sequence of scanning. In the present embodiment, it is confirmed whether the first line includes printing or not in a step 801. The confirmation is similar to the case shown in Fig. 7. First, the sensor is made to scan in a perpendicular direction, and to scan in a horizontal direction for confirmation when no printing is included. If no printing is recognized when scanning is made in the perpendicular direction and existence of printing is recognized in the horizontal direction, error indication is shown. In these figures, a first nonprinted line is referred to as a F.N.P.L. Detection and confirmation operation similar to that in the step 801 is performed thereafter in respective steps 802 to 824 shown in Figs. 8A and 8B. Besides, scanning in the horizontal direciton which is performed for confirmation of printing in respective steps is performed with respect to a line which becomes the object and lines above and under the objective line. Although the present invention has been described in detail, it should be understood that various changes, substitutions and alterations can be made hereto without departing from the scope of the present invention as defined by the appended claims. | A passbook or the like handling apparatus for handling a passbook or the like in which contents of transactions are printed line by line in order from an upper edge thereof downward, comprising: a first sensor (5) for scanning a passbook or the like (6) in a direction perpendicular to printed lines thereof so as to detect whether printing is included therein or not; characterised by a second sensor (5) for scanning the passbook or the like (6) in a direciton horizontal to the printed lines so as to detect whether printing is included therein or not; and means (1) for specifying a first nonprinted line based on the result of detection by said first and second sensors (5). A passbook or the like handling apparatus according to Claim 1, further comprising a scanning control means (1) for having said first sensor (5) perform scanning in the first place, detecting whether printing is included in a locus of scanning, and then having the second sensor (5) perform scanning. A passbook or the like handling apparatus according to Claim 2, wherein said scanning control means (1) controls so that: said first sensor (5) performs scanning in order of printing from the uppermost printed line, i.e., in order from the top to the bottom of the passbook or the like; and said second sensor (5) performs scanning of the first nonprinted line detected by said first sensor (5) in a printing direction, i.e., in a horizontal direction. A passbook or the like handling apparatus according to Claim 2, wherein said scanning control means (1) controls so that: said first sensor (5) performs scanning in order of printing from the first printed line, i.e., in order from the top to the bottom of the passbook or the like (6); and said second sensor (5) performs scanning of the first nonprinted line detected by said first sensor (5) and lines above and under that line in a horizontal direction. A passbook or the like handling apparatus according to Claim 4, wherein said scanning control means (1) controls so that said first sensor (5) scans the edges of said printed lines. A passbook or the like handling apparatus according to Claim 5, wherein date data are printed at the edges of said printed lines. A passbook or the like handling apparatus according to Claim 2, wherein said scanning control means (1) controls so that said first sensor (5) scans predetermined printed lines in predetermined order. A passbook or the like handling apparatus according to Claim 7, wherein said scanning control means (1) controls so that said second sensor (5) scans a first nonprinted line detected by said first sensor (5) and lines above and under that line. A passbook or the like handling apparatus according to Claim 8, wherein said scanning control means (1) controls said first sensor (5) in such a manner that: an uppermost printed line is detected in the first place; a lowermost printed line is checked in the next place in case that line has been printed; a central line is checked in case said lowermost line has not been printed; scanning is performed from a line next to said central line and downward in order in case said central line has been printed; and scanning is performed from a line next to said uppermost line and downward in order in case said central line has not been printed. A passbook or the like handling apparatus according to Claim 9, wherein: said passbook or the like (6) includes 24 lines in one page; and said scanning control means (1) controls said first sensor (5) in such a manner that; the first line is checked in the first place, and the 12th line is checked in case the first line has been printed; the 24th line is checked in case the 12th line has been printed; the 6th line is checked in case the 12th line has not been printed; the 9th line is checked in case the 6th line has been printed; the 3rd line is checked in case the 6th line has not been printed; the 10th line is checked in case the 9th line has been printed; the 11th line is checked in case the 10th line has been printed; the 7th line is checked in case the 9th line has not been printed; the 8th line is checked in case the 7th line has been printed; the 4th line is checked in case the 3rd line has been printed; the 5th line is checked in case the 4th line has been printed; the 2nd line is checked in case the 3rd line has not been printed; the 18th line is checked in case the 24th line has not been printed; the 21st line is checked in case the 18th line has been printed; the 15th line is checked in case the 18th line has not been printed; the 22nd line is checked in case the 21st line has been printed; the 23rd line is checked in case the 22nd line has been printed; the 19th line is checked in case the 21st line has not been printed; the 20th line is checked in case the 19th line has been printed; the 16th line is checked in case the 15th line has been printed; the 17th line is checked in case the 16th line has been printed; the 13th line is checked in case the 15th line has not been printed; and the 14th line is checked in case the 13th line has been printed. A passbook or the like handling apparatus according to Claim 1, further comprising: printing means (3) for printing in said passbook or the like, the printing means (3) being movable in a perpendicular direction and a horizontal direction with respect to printed lines; and means (1, 7) for positioning said printing means (3) at a first nonprinted line at the head specified by the means (1) for specifying said nonprinted line. A passbook or the like handling apparatus according to Claim 11, wherein said first sensor (5) and said second sensor (5) consist of one sensor (5) movable in a perpendicular direction and a horizontal direction, and this sensor (5) is fitted to said printing means (3). A method of specifying a first nonprinted line, in which contents of following transactions are to be printed, of a passbook or the like (6) in which contents of transactions are printed line by line in order from an upper edge thereof and downward, comprising the steps of: scanning the passbook or the like (6) in a direction perpendicular to printed lines thereof; detecting a first nonprinted line in a locus of scanning; and characterised by scanning in a horizontal direction in the next place so as to confirm whether printing is included in said first nonprinted line. | HITACHI LTD; HITACHI, LTD. | BABA KIMIO; FUJIMOTO NOBUO; INOUE MASASHI; BABA, KIMIO; FUJIMOTO, NOBUO; INOUE, MASASHI |
EP-0490242-B1 | 490,242 | EP | B1 | EN | 19,960,522 | 1,992 | 20,100,220 | new | D01H1 | null | D01H1, D01H7 | D01H 1/244 | Spindle arrangement of a textile machine | The subject-matter of the invention is a spindle (1) directly driven by an electrical motor, a plurality of which are mounted on a spindle rail (15) of a textile machine to constitute a row. For avoiding contacts between the spindles at least one of sides of at least one of surfaces of an electrical motor body (31) of said spindle is cut away along an overall length of said electrical motor body (31) in an axial direction thereof, said surfaces facing to electrical motor bodies (31) of adjacent spindles. At least two corners of a basical rectangle, as seen from the top of a spindle, are bevelled so as not to come into contact with each other. As a result, such spindles can be easily installed on a textile machine by using the same spindle gages, without increasing the accuracy with which the spindles are installed. | The invention relates to a spindle arrangement of a textile machine according to the first part of claim 1. In textile machines such as ring spinning machines, generally, several hundred spindles are aligned horizontally on a spindle rail. Because of the many aligned spindles, the spindle gages G at which the spindles are installed directly affect the area where the textile machines are installed. It it thus necessary to narrow the spindle gage G to reduce such an area as much as possible, whereby the entire textile machine can be made smaller. A type of spindle, whose shaft is directly driven by a spindle motor, (hereinafter referred to simply as a spindle) has been frequently used in recent years. A power line connector to the spindle motor and accessories (such as a start/stop switch) are attached to such a spindle. Because it is required to reduce the area where the textile machine is installed, these components must not be attached on a surface of the spindle which faces another spindle, but be attached on a surface of the spindle which does not face another spindle. The textile machine is employed in an environment where there is a great amount of cotton and other types of dust, and therefore, the power line connector and accessories are covered to protect them from dust. The JP-A- 2-19521 discloses a spindle, in which the outline of its housing , as seen from the top of the spindle shaft thereof, is either a square corresponding to the shape of a spindle motor or a rectangle having a cover for accessories and other components. Such rectangular spindles are installed on a spindle rail so that one short side (width) of each spindle becomes parallel to the spindle rail and one long side (length) thereof becomes perpendicular to the spindle rail. The gaps between the spindles thus installed are extremely narrow. Fig. 1 shows how conventional spindles are installed as seen from the tops of the spindle shafts thereof. In this drawing, each spindle is schematically shown by the outline thereof as seen from the top thereof. The outline of each spindle is composed of lines a1 and a 2, corresponding to long sides (lengths) H16, and lines b1 and b2, correspond to short sides (widths) W16, of each spindle. Symbol G indicates a spindle gage, and a circle D16 indicates where the spindle motor is disposed. When a conventional spindle 1₋₃ having such an outward shape rotates on the spindle shaft through even a small angle of only 16, it interferes with the spindle 1₋₂ next to it. Such narrow gaps between the spindles cause the following problems: (1) To prevent the spindles from interfering with each other, it is necessary not only to increase the accuracy with which the spindles are installed, but also to improve the degree to which the spindles are parallel to each other. (2) It is necessary to install the rectangular spindle onto the spindle rail so that the long sides of the spindle becomes accurately perpendicular to the spindle rail. This installation is troublesome and requires a considerable amount of time. (3) The area available to cool the spindle motor is small; consequently, the temperature of the motor may increase. (4) Because it is difficult for wind to flow between the spindles, it is also difficult to remove cotton dust. (5) If all of the gaps between the spindles are equally widened, because of limited spindle gages, the size of the motor within the spindle becomes small, thereby decreasing the efficiency of the spindles. An object of the present invention is to provide spindles which do not come into contact with each other, without increasing the accuracy with which the spindles are installed or improving the degree to which the spindles are parallel to each other, and, as a result, the spindles can be easily installed in a short period of time. To achieve the above objects, in accordance with the present invention, there is provided a spindle arrangement having the features of claim 1 and 2, respectively. A plurality of directly driven spindles are mounted on a spindle rail of a textile machine to constitute a row. A outline of a periphery of the spindle housing as viewed from an axial direction of said spindle is included within a rectangle in a part of 20% and more of length of a long side of said rectangle. The rectangle is defined by short sides (b1, b2) parallel to an ideal straight line (α) and respectively passing at a point where a distance from an axial center (o) of said spindle to said outline becomes maximum and long sides (aA, a2) perpendicular to said ideal straight line (α) and longer than said short sides (b1, b2), one (a1) of said long sides passing a point (p) and the other (a2) passing another point (q), wherein said point (p) comprises a point where a distance from the axial center (o) of said spindle to said outline becomes minimum and said other point (q) comprises a point disposed contrary to said point (p) with respect to the axial center (o) and said ideal straight line (α) comprises a line passing through said points (p, q). The spindles are installed on the spindle rail so that one short side (width) of each spindle becomes parallel to the spindle rail and one long side (length) thereof becomes perpendicular to the spindle rail. The outward shape of the spindle is such that the width of the short side of the spindle is shorter than the maximum width. Therefore, the spindles can be installed without interfering with each other. BRIEF DESCRIPTION OF THE DRAWINGSFig. 1 is a plan view showing how the conventional spindles are installed as seen from the tops of the spindle shafts thereof; Fig. 2 is a view showing an embodiment of a textile machine using spindles according to the present invention; Fig. 3 shows an embodiment of a spindle according to the present invention; Fig. 3(a) is a plan view of the spindle; Fig. 3(b) is a side view as seen perpendicularly to a surface A; and Fig. 3(c) is a side view as seen perpendicularly to a surface B; Fig. 4 is a plan view showing an embodiment of the present invention where the two diagonally opposing corners of each rectangle spindle are cut; Fig. 5 is a plan view showing how the spindles, each having the outward shape shown in Fig. 4, are installed; Fig. 6 is a graph showing cooling effect when the ratio w/W of the minimum width w to the maximum width W of the spindle changes. Fig. 7 is a plan view showing an embodiment of a spindle according to the present invention, in which all corners of the originally rectangular spindle are cut; Fig. 8 is a plan view showing how the spindles, each having the outward shape shown in Fig. 7, are installed; Fig. 9 is a plan view showing an embodiment of a spindle according to the present invention, in which all corners of the originally rectangular spindle are cut, and a portion of a circle is used to form the surfaces A; Fig. 10 is a plan view showing an embodiment of a spindle according to the present invention, in which all corners of the originally rectangular spindle are cut, and the surfaces A are in contact with a circle; Fig. 11 is a plan view showing an embodiment of a spindle according to the present invention, in which all corners of the originally rectangular spindle are cut, and a part of a circle is used to connect portions of short sides of the spindle to portions of the long sides of the spindle which the width of the spindle is the maximum width; Fig. 12 is a plan view showing an embodiment of a spindle according to the present invention, in which all corners of the originally rectangular spindle are cut, and the outward shape of the spindle is a combination of a part of a circle and a part of the rectangle; Fig. 13 is a plan view showing an embodiment of a spindle according to the present invention, in which all corners of the originally rectangular spindle are cut, and the outward shape of the spindle is a combination of rectangles; Fig. 14 is a plan view showing an embodiment of a spindle according to the present invention, in which all corners of the originally rectangular spindle are cut so as to correspond to the shape of an ellipse; Fig. 15 is a plan view showing an embodiment of a spindle according to the present invention, in which all corners of the originally rectangular spindle are cut, and a degree to which two corners of one long side of the spindle are cut differs from a degree to which two corners of another long side of the spindle are cut; Fig. 16 is a plan view showing an embodiment of a spindle according to the present invention, in which spindles, whose two corners of one short side thereof are cut, are alternately disposed; Fig. 17 is a plan view showing an embodiment of a spindle according to the present invention, in which the two corners of the originally rectangular spindle are cut and accessaries are attached to the spindle; Fig. 18 through Fig. 21 are plan views each showing an embodiment of a spindle according to the present invention, in which two corners of one long side of the originally rectangular spindle are cut. DESCRIPTION OF THE PREFERRED EMBODIMENTSFig. 2 is a view showing an embodiment of a ring spinning machine, which is a textile machine. A roving 10 wound around a package 11 is stretched when it passes through a draft part 12. It then passes through a ring (not shown) of a ring rail 20, and is wound around a bobbin 13 on one of many spindles 1. The spindles 1 are spindles which are integral with and directly driven by spindle motors, and are arranged on a spindle rail 15. An inverter 19 controls the speed of the spindles 1. Draft rollers 16 of the draft part 12 are rotated by a motor 18, whose speed is controlled by an inverter 17. The ring rail 20 is moved back and forth by rotating a screw spindle 23 clockwise or counterclockwise, which spindle 23 is fixed on a motor 21. The speed of the motor 21 is controlled by another inverter 22. Gaps are very narrow between the spindles of the thus-constructed ring spinning frame. Because of the narrow gaps, there have hitherto been problems mentioned previously with the conventional art. Fig. 3 shows an embodiment of a spindle, according to the present invention, which solves such problems. Numeral 31 denotes a housing of the spindle motor, and numeral 32 denotes a bracket of the same motor. Numeral 33 denotes an upper blade constituting a portion of the spindle shaft. The upper blade 33 is tapered and becomes thinner as it approaches one end thereof. The upper blade 33 is inserted into a bobbin (not shown) for winding the roving. Numeral 34 denotes a bolster extending opposite to the upper blade 33. It covers a vibration-absorbing member absorbing virbrations caused by the spindle shaft and the rotation of the motor and other members. A switch 36 is disposed on the housing 31, which is used to start and stop the spindle 1 independently. A cable 37 including a power wire and a signal wire for the switch 36 extends from the housing 31. As shown in Fig. 3, the spindle 1 is fixed by a nut 35 to a hole bored in the spindle rail 15. Fig. 4 is a simplified plan view showing the outlines of the spindles 1 as seen from the tops of the spindle shafts. Of the adjacent spindles 1, two spindles 1 are shown in this drawing. According to this embodiment the outlines of the spindles 1 form rectangles, as seen from the tops of the spindle shafts, with the two opposing corners bevelled. This is a unique feature of this invention, different from the conventional spindle which also forms the outline of a rectangle but with the four corners thereof left intact. As shown in Fig. 4, symbol H9 indicates lengths of long sides of the rectangle (hereinafter referred to as maximum lengths), and symbol W9 indicates widths of short sides (hereinafter called maximum widths). The spindle shaft and a motor shaft are disposed on the same center within a circle D9 in contact with the long sides so that these two shafts form an integral structure. The outline of the spindle 1 is composed of lines drawn substantially along the long sides, lines drawn substantially along the short sides and lines drawn along the bevelled corners. Surfaces corresponding to these lines are not necessarily planes. Lines connecting outer edges of the surfaces form the outline of the spindle 1 shown in Fig. 4. The outward shape of the spindle 1 may be such that, for example, a cooling fin, have an uneven surface thereof, indicated by symbol F, is disposed in at least a part of the spindle 1. Symbol h9 indicates a length of a portion of the long side, at which the width of the outline is the maximum width W9. Fig. 5 is a plan view where a spindle 1₋₃ is inclined through an angle of only 9 while the spindles, each having the shape shown in Fig. 3 or Fig. 4, are installed and stand upright on the machine. As shown in Fig. 1, the outline of the conventional spindle forms a rectangle as seen from the top of the spindle shaft. (Symbol H16 indicates the length, and symbol W16 indicates the width of the rectangle). Because of such an outline, even when a spindle 1₋₃ rotates slightly through an angle of 16, it interferes with the spindle 1₋₂ next to it. However, according to this embodiment, as shown in Fig. 5, the two corners of each spindle are bevelled so that the length w9 of their short sides becomes shorter than the maximum width W9. Owing to this outline, even when the spindle 1₋₃ rotates, there is more gap where the spindles are not in contact with each other than in the case of the conventional art. In other words, the following relationship can be established between the rotation angles 9 and 16: 9 > 16 The following relationship can be obtained between the maximum length H9 and the length h9: H9 > h9 If, for example, a spindle gage G is 75 mm; the gap 59 between the spindles is 4 mm; the maximum length H9 is 100 mm; the ratio h9/H9 of the length h9 to the maximum length H9 is 1/3; and the ratio w9/W9 of the width w9 to the maximum width W9 is 2/3, then, the angle 16 is approximately 4.7°, and the angle 9 is approximately 37°. Thus, the spindle according to this embodiment shown in Fig. 3 or 4 is capable of inclining eight times as much as the conventional spindle. In other words, the gap S9 between the spindles shown in Fig. 5 can be made smaller than the gap S16 between the conventional spindles shown in Fig. 1. Thus, even when the spindle gage G is the same, the maximum width W9 of the spindle can be increased, and the size of an electrical portion of the motor can also be increased. Consequently, the iron loss of the motor can be reduced, and the efficiency of the motor can be improved. When spindles each having, for instance, the above sizes are arranged, it is possible to set the gap S9 between the spindles to 1 to 1.5 mm. That is, the ratio S9/S16 of the gap S9 according to this embodiment to the gap S16 of the conventional spindles can be set at 1/4 to 1/3. In such a case, it is possible to increase the outward size of an iron core of the motor by 3 to 5%, and to improve the efficiency thereof by 1 to 3%. Because of the widened gap S9 between the spindles, the spindles become well-ventilated and the cooling efficiency thereof can be improved. As a result, it is possible to reduce an increase in the temperature of the motor. When the ratio h9/H9 of the length h9 to the maximum length H9 is approximately 0.8 or less, the ratio is practical and an advantageous effect can be obtained. Fig. 6 is a graph showing cooling effect when the ratio h9/H9 is 1/3 and when the ratio w9/W9 of the width w9 to the maximum width W9 changes. When attaching the switch and extending a lead-out wire are considered, the cooling effect improves where the ratio w9/W9 (indicated by w/W in Fig. 6) ranges from 0.95 to 0.6. Cotton and other types of dust collect between the spindles and on other places, and therefore, wind is blown to remove it. However, according to this embodiment, because of the widened gap between the spindles, wind smoothly flows into the gap, thus effectively removing dust. As shown in Fig. 4, because the two diagonally opposing corners of the outline of the spindle 1 are bevelled as seen from the top of the spindle shaft, the other two diagonal corners C which are not bevelled can be used for attaching accessories 36 or for leading the cable 37. Then, another embodiment of the invetion will be explained with reference to Figs. 7 and 8. An outline of the spindle 1 is located within a rectangle of which length of long sides in referred as H17 and length of short sides is referred as W17. The outline of the spindle comprises a shape of which all of the four corners of the rectangle are bevelled. Symbol h17 incidates a length of a portion of the outline, at which the width of the outline is a maximum width W17. Symbol w17 indicates the width of the short side of the outline. The spindle shaft and a motor shaft are disposed on the same center within a circle D1 in contact with the long sides a1 and a2 so that these two shafts form an integral structure. The outline of the spindle 1 is composed of lines drawn substantially along the long sides, lines drawn substantially along the short sides, and lines drawn substantially along the four bevelled corners. Surfaces corresponding to these lines are not necessarily planes. Lines connecting outer edges of the surfaces form the outline of the spindle 1 shown in Fig. 7. The outward shape of the spindle 1 may be such that, for example, a cooling fin, have an uneven surface thereof, indicated by symbol F, is disposed in at least a portion of the spindle 1. Fig. 8 is a plan view partially showing how the spindles, each having the outward shape shown in Fig. 7 as seen from the tops of the spindle shafts thereof, are installed on a machine. As shown in this drawing, all four corners of each spindle 1 are bevelled so that the length h17 is shorter than the length H17 of the long side of each spindle 1. Because of the four bevelled corners, there is more gap between the spindles than in the case of the conventional art, even when a spindle 1₋₃ inclines. In the same way as in the embodiment shown in Fig. 4, the following relationship can be established between the rotation angles 16 and 17: 17 > 16 Thus this embodiment maskes it possible for the gap between the spindles to be almost as wide as the gap in the embodiment shown in Fig. 4. In the same manner as in the embodiment shown in Fig. 4, when the ratio h17/H17 of the length h17 to the maximum length H17 is approximately 0.8 or less, such a ratio is practical and an advantageous effect can be obtained. When the ratio w17/W17 of the width w17 to a maximum width W17 ranges from 0.95 to 0.6, the spindles can be effectively employed. In this embodiment, because there is more gap between the spindles than in the case of the conventional art, wind flows smoothly in the same way as in the embodiment shown in Fig. 4, and thus cotton and other types of dust can be effectively removed. Figs. 9 through 15 show modifications of the embodiment shown in Fig. 7, in which the four corners of each rectangle are all bevelled. Spindles shown in Figs. 9 and 10 are spindles each having no length corresponding to the length h17 of the spindle 1 shown in Fig. 7. An outline of the spindle 1 shown in Fig. 9 is shaped in such a manner that a circle having a diameter D2 which is equal to a maximum width W2 is drawn so that a part of this circle corresponds to a part of the outline of the spindle 1. The spindle 1 has no straight line corresponding to the length h17 of a portion of the spindle 1 where the width of the spindle 1 is the maximum width W2. In this embdoiment, permissible angle for mounting the spindles becomes larger than the embodiment of Fig. 7, and the gap between the spindles can be widened; consequently, the spindles are more effectively cooled. An outline shown in Fig. 10 has no straight line corresponding to the length h17 of a portion of the spindle 1, at which the width of the spindle 1 is a maximum width W3 in the same way as in the embodiment illustrated in Fig. 9. However, the lines of the bevelled corners are in contact with a circle D3. In other words, the diameter of the circle D3 is shorter than the maximum width W3. The same advantageous effect as that described in the embodiment shown in Fig. 9 can be obtained. An outline shown in Fig. 11 is similar to that shown in Fig. 7. An outline of the spindle comprises lines of which length is referred as w4 on the short sides, lines of which length is referred as h4 on the long sides and line portions connecting the lines of the short sides and the lines on the long sides. The line portions are a part of a circle of which radius is R4. The spindle 1 in this embodiment has a wider outer periphery thereof than the spindle 1 in the embodiment shown in Fig. 7, and is therefore cooled effectively. An outline of an embodiment shown in Fig. 12 is a combination of a rectangle comprising long sides having a length H5 and short sides having a length w5 and portions of a circle having a diameter D5. A gap between adjacent spindles can be widened closer to a center portion than the embodiments shown in Figs. 4, 7 and 9-11. The cooling effect is further increased. An outline of an embodiment shown in Fig. 13 is a combination of a rectangle of which long sides have a length H6 and short side have a length w6 and another rectangle of which long sides have a length W6 and short sides have a length h6. The cooling effect of this embodiment is substantially the same as the embodiment shown in Fig. 12 but it is suitable for a case in which the length w6 is made larger than the length w5. An outline of an embodiment shown in Fig. 14 comprises an ellipse of which a major axis has a length corresponding to a length H7 of long sides of a rectangle and a minor axis has a length corresponding to a length W7 of short sides of the rectangle. According to the present embodiment, permissible angle for mounting can be increased and the irregularity of a spindle arrangement after mounted is inconspicuous. In an outline of an embodiment shown in Fig. 15, a bevelled amount of one side of the surface A is different from those of the other side. In the present embodiment, it is possible to use the small bevelled amount corners for connecting lead wires to the motor and for mounting accessaries. In an outline of an embodiment shown in Fig. 16, two corners on one of short sides of the rectangle are bevelled. In the present embodiment, the spindles are alternately disposed with different attitude as shown in Fig. 16. Also in the present embodiment, the same advantages as those of the previously explained embodiments can be obtained. Figs. 17 to 21 show embodiments shaped so as to be unsymmetrical with respect to longitudinal axis running at a center of the spindle shaft. In an outline of an embodiment shown in Fig. 17, two corners on one of long sides of the rectangle are bevelled with straight lines in the same manner as those of one side in the embodiment shown in Fig. 7. In an outline of an embodiment shown in Fig. 18, two corners on one of long sides of the rectangle are bevelled with a part of a circle in the same manner as those of one side in the embodiment shown in Fig. 11. In an outline of an embodiment shown in Fig. 19, two corners on one of long sides of the rectangle are bevelled with a part of circle having a diameter D2 equal to the maximum width W2 of the spindle in the same manner as those of one side in the embodiment shown in Fig. 9. In an outline of an embodiment shown in Fig. 20, two corners on one of long sides of the rectangle are bevelled with a part of an ellipse in the same manner as those of one side in the embodiment shown in Fig. 12. In an outline of an embodiment shown in Fig. 21, two corners on one of long sides of the rectangle are bevelled with a part of a circle D15 and a part of a rectangle having a long side H15 and a short side w15 in the same manner as those of one side in the embodiment shown in Fig. 12. Only the two opposing corners of one long side of each spindle 1 are bevelled in all the embodiments shown in Figs. 17 through 21. For this reason, the other two corners C of each spindle 1 can be used for attaching accessories 36 or leading the cable 37 in the same manner as in the embodiment shown in Fig. 4 described above. As is apparent from the description of the embodiments hereinbefore, according to the present invention, it is possible to mount the spindles so as not to come into contact with each other without increasing the mounting accuracy of the spindles and the parallel accuracy of the surfaces of adjacent spindles facing to each other. Therefore, spindles which are easily mounted with less operational time and a textile machine using the spindles can be provided. | A spindle arrangement of a textile machine constituting a row of adjacent spindles (1) adapted to be mounted on a spindle rail (15) and each being driven by an electrical motor, each spindle having a housing (31) 'with first side surfaces (a₁, a₂) facing the housings of adjacent spindles, characterized in that each of the first surfaces (a₁, a₂) is provided with at least one bevelled portion extending axially along the respective first side surface (a₁, a₂) of the housing (31), the bevelled portion being dimensioned so as to increase the possible angular movement of the housing (31) around a center (o) thereof. A spindle arrangement according to the first part of claim 1, characterized in that one of the first surfaces (a₁, a₂) is provided with two bevelled portions extending axially along the respective first side surface (a₁, a₂) of the housing, the bevelled portions being dimensioned so as to increase the possible angular movement of the housing (31) around a center (o) thereof. Spindle arrangement according to claims 1 or 2, characterized in that second side surfaces (b₁, b₂) of the housing (31) are provided parallel to a line (α) passing through the axial center (o) and being perpendicular to said first side surfaces (a₁, a₂), and a ratio (h₉/H₉) of a length (h₉) of said first side surfaces (a₁, a₂) at which the housing (31) has its maximum width to the total length (H₉) of said side surfaces (a₁, a₂) is equal or less than 0.8. Spindle arrangement according to one of claims 1 to 3, characterized in that said first side surfaces (a₁, a₂) having a length longer than said second side surfaces (b₁, b₂), one (a₁) of the first side surfaces (a₁, a₂) is passing through a first point (p) and the other first side surface (a₂) is passing through a second point (q), wherein the first point (p) is provided at the point of intersection with line (α), the second point (q) is provided opposite to the point (p) with respect to the axial center (o) at the point of intersection with line (α). Spindle arrangement according to one of the claims 1 to 4, characterized in that said bevelled portions are located symmetrically with respect to an axial center (o) of the housing (31). Spindle arrangement according to claim 1, characterized in that the outer surface of the housing (31) is substantially ellipsoidal. Spindle arrangement according to one of claims 1 to 6, characterized in that cooling fins (F) having an uneven surface are provided at a portion of the spindle housing (31). | HITACHI LTD; HITACHI, LTD. | KOBAYASHI HIDEAKI; MATSUI HIDEKAZU; KOBAYASHI, HIDEAKI; MATSUI, HIDEKAZU |
EP-0490244-B1 | 490,244 | EP | B1 | EN | 19,950,607 | 1,992 | 20,100,220 | new | G01C19 | G01P9 | G01P9, G01C19 | G01C 19/56B3 | Detecting circuit for detecting an abnormal state in a vibrating gyroscope | A detecting circuit (10) has two diodes (16a,16b) for rectifying an oscillation signal for driving a vibrator (2) of a vibrating gyroscope (1) and a detection signal for detecting an angular velocity of the vibrator in either sense. The diodes are connected with two resistors (20a,20b) for composing these rectified signals. A connection point (21) of the resistors is connected to a base of a PNP transistor (22). The emitter of the transistor is connected to a positive potential and a collector thereof is grounded through a resistor (26). Further, an output terminal (28) is connected to the collector of the transistor. | BACKGROUND OF THE INVENTIONField of the InventionThe present invention relates to a detecting circuit, and specifically relates to a detecting circuit capable of detecting an abnormal state of a vibrating gyroscope. Description of the Prior ArtFig. 2 is a block diagram showing an example of a conventional vibrating gyroscope, which is the background of the present invention and whereto the present invention is applied. Such a gyroscope is known from JEE Journal of Electronic Engineering, vol. 27, no. 285, September 1990, Tokyo, JP, pages 99-104 : Takeshi Nakamura Vibration Gyroscope Employs Piezoelectric Vibrator . In the vibrating gyroscope 1, piezoelectric elements 3a and 3b for driving and detecting are formed on two side surfaces of a triangular prism-shaped vibrator 2, and a piezoelectric element 4 for feedback is formed on the other side of the vibrator 2. The piezoelectric element 4 for feedback is connected to the piezoelectric elements 3a and 3b through an oscillation circuit 5 and a phase-shifting circuit 6. Further, the piezoelectric elements 3a and 3b are connected to two input terminals of a differential amplifier circuit 7 consisting of, for example, a differential amplifier, respectively. Also, an output terminal of the differential amplifier circuit 7 is connected to an input terminal of a synchronous detection circuit 8. The phase-shifting circuit 6 is connected to the synchronous detection circuit 8 to detect an output of the differential amplifier circuit 7 in synchronism with a driving signal of the vibrator 2. Further, an output terminal of the synchronous detection circuit 8 is connected to a rectifying/amplifying circuit 9 for rectifying and amplifying an output of the synchronous detection circuit 8. In the vibrating gyroscope 1 as shown in Fig. 2, the vibrator 2 is driven by self-excited vibration by a feedback loop such as the oscillation circuit 5 and the phase-shifting circuit 6. In this case, the two piezoelectric elements 3a and 3b generate similar sine wave signals. Consequently, output voltages of the differential amplifier circuit 7, the synchronous detection circuit 8 and the rectifying/amplifying circuit 9 become nearly 0V, respectively. Here, when the vibrator 2 is rotated around the shaft thereof, in response to the rotary angular velocity of the vibrator 2, the voltage of the sine wave signal generated in one of the two piezoelectric elements 3a and 3b becomes large, and the voltage of the sine wave signal generated in the other one becomes small. Consequently, a sine wave signal of a magnitude responding to the rotational angular velocity of the vibrator 2 is outputted from the differential amplifier circuit 7. Then, the sine wave signal outputted from the differential amplifier circuit 7 is synchronized-detected by the synchronous detection circuit 8, and is rectified and amplified by the rectifying/amplifying circuit 9. Accordingly, the vibrating gyroscope 1 can detect the rotational angular velocity by the output voltage from the differential amplifier circuit 7, the synchronous detection circuit 8 or the rectifying/amplifying circuit 9. For this reason, the vibrating gyroscope 1 is used, for example, for attitude control of a motorcar. However, in the case where the vibrating gyroscope 1 of Fig. 2 is used, for example, for attitude control of a motorcar, the attitude control of the motorcar is required to be performed only after making sure that the vibrating gyroscope 1 is operated in normal state. Because, for example, when the vibrating gyroscope is operated in an abnormal state such that a connection line connected to each piezoelectric element is disconnected or short-circuited, an abnormal signal is outputted from the vibrating gyroscope, and when the abnormal signal is used intact as a signal for control, a dangerous state sometimes takes place. SUMMARY OF THE INVENTIONTherefore, a principal object of the present invention is to provide a detecting circuit which can detect an abnormal state of a vibrating gyroscope. The present invention is directed to a detecting circuit for detecting an abnormal state in a vibrating gyroscope which generates an oscillation signal for driving a vibrator and a detection signal for detecting a rotary angular velocity of the vibrator, which comprises a first rectifying means for rectifying the oscillation signal, a second rectifying means for rectifying the detection signal in the direction reverse to the oscillation signal rectified by the first rectifying means, a composite means for composing the oscillation signal rectified by the first rectifying means and the detection signal rectified by the second rectifying means, and a switching device which is switched by a composite signal composed by the composite means. The oscillation signal of the vibrating gyroscope is rectified by the first rectifying means. Also, the detection signal of the vibrating gyroscope is rectified by the second rectifying means in the direction reverse to the oscillation signal rectified by the first rectifying means. Then, the oscillation signal and the detection signal which have been rectified by the first rectifying means and the second rectifying means are composed by the composite means. The switching device is switched by the composite signal composed by the composite means. On the other hand, the oscillation signal or the detection signal of the vibrating gyroscope when the vibrating gyroscope is operated in normal state differs from that when the vibrating gyroscope is operated in an abnormal state. Accordingly, the composite signal composed by the composite means of the detecting circuit when the vibrating gyroscope is operated in normal state differs from that when the vibrating gyroscope is operated in an abnormal state, and ON/OFF state of the switch device also differs. For this reason, the detecting circuit can detect an abnormal state of the vibrating gyroscope from ON/OFF state of the switching device. In accordance with the present invention, a detecting circuit is obtainable which can detect an abnormal state of a vibrating gyroscope. The above and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the embodiments with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGSFig. 1 is a circuit diagram showing an embodiment of the present invention. Fig. 2 is a block diagram showing an example of a conventional vibrating gyroscope, which is the background of the present invention and whereto the present invention is applied. Fig. 3 is a graph showing an oscillation signal and a detection signal of the vibrating gyroscope and an output signal of a detecting circuit when the vibrating gyroscope is operated in normal state in the case where the detecting circuit as shown in Fig. 1 is connected to the vibrating gyroscope as shown in Fig. 2. Fig. 4 is a graph showing an oscillation signal and a detection signal of the vibrating gyroscope and an output signal of the detecting circuit when the vibrating gyroscope is operated in an abnormal state in the case where the detecting circuit as shown in Fig. 1 is connected to the vibrating gyroscope as shown in Fig. 2. Fig. 5 is a graph showing an oscillation signal and a detection signal of the vibrating gyroscope and an output signal of the detecting circuit when the vibrating gyroscope is operated in another abnormal state in the case where the detecting circuit as shown in Fig. 1 is connected to the vibrating gyroscope as shown in Fig. 2. DESCRIPTION OF THE PREFERRED EMBODIMENTSFig. 1 is a circuit diagram showing an embodiment of the present invention. A detecting circuit 10 comprises two input terminals 12a and 12b. One input terminal 12a is for inputting an oscillation signal of a vibrating gyroscope, and is connected to a cathode of a diode 16a as a first rectifying means through a capacitor 14a. The diode 16a is for rectifying an oscillation signal of the vibrating gyroscope. The cathode of the diode 16a is connected to a positive potential through a resistor 18a. Also, the other input terminal 12b is for inputting a detection signal of the vibrating gyroscope, and is connected to an anode of a diode 16b as a second rectifying means through a capacitor 14b. The diode 16b is for rectifying a detection signal of the vibrating gyroscope in the direction reverse to the oscillation signal of the vibrating gyroscope rectified by the diode 16a. The anode of the diode 16b is also connected to the positive potential through a resistor 18b. Furthermore, an anode of the diode 16a and a cathode of the diode 16b are connected through two resistors 20a and 20b as a composite means. These resistors 20a and 20b are for composing the oscillating signal and the detection signal of the vibrating gyroscope rectified by the diodes 16a and 16b. This means that these resistors 20a and 20b are for generating a composite signal composed with the rectified oscillation signal and detection signal at a connection point 21 thereof. Also, the connection point 21 of these resistors 20a and 20b is connected, for example, to a base of a PNP transistor 22 as a switching device. Further, the base of the transistor 22 is connected to the positive potential through a capacitor 24. The capacitor 24 is for stably keeping a base potential of the transistor 22. Also, a emitter of the transistor 22 is connected to the positive potential. Further, a collector of the transistor 22 is grounded through a resistor 26. Accordingly, the transistor 22 is put in ON state when the base potential thereof is low, and put in OFF state when the base potential thereof is high. Furthermore, to the collector of the transistor 22, an output terminal 28 is connected. Accordingly, the output terminal 28 goes high when the transistor 22 is in ON state, that is, when a collector current flows, and goes low when the transistor 22 is in OFF state, that is, when the collector current scarcely flows. Next, description is made on operation and the like of the detecting circuit 10 taking the case of connecting the detecting circuit 10 to the vibrating gyroscope 1 as shown in Fig. 2 as an example. In this case, the input terminals 12a and 12b of the detecting circuit 10 are connected to the output terminal 5a of the oscillation circuit 5 and the output terminal 7a of the differential amplifier circuit 7 of the vibrating gyroscope 1, respectively. In the detecting circuit 10, the oscillation signal of the vibrating gyroscope 1 is rectified in the forward direction of the transistor 22 by the diode 16a. Also, the detection signal of the vibrating gyroscope 1 is rectified in the reverse direction by the diode 16b. Further, the rectified oscillation signal and detection signal are composed by the two resistors 20a and 20b. Then, the composed composite signal is applied to the base of the transistor 22. Where the vibrating gyroscope 1 is operated normally, as shown in Fig. 3, the voltage of the oscillation signal from the oscillation circuit 5 for driving the vibrator 2 is large and outputs of piezoelectric elements 3a and 3b for detection are balanced with each other, and therefore the voltage of the detection signal from the differential amplifier circuit 7 for detecting the rotational angular velocity of the vibrator 2 is small. Consequently, the potential of the composite signal composed by the two resistors 20a and 20b is low, and the base potential of the transistor 22 is also low. Accordingly, the transistor 22 is put in ON state, and the output terminal 28 goes high. On the other hand, in the vibrating gyroscope 1, in the case of an abnormal state where one of connection lines from the piezoelectric elements 3a and 3b to the differential amplifier circuit 7 is disconnected or short-circuited, an imbalance takes place between the outputs of the piezoelectric elements 3a and 3b for detection, and therefore, as shown in Fig. 4, the detection signal of the vibrating gyroscope 1 becomes large. Consequently, the potential of the composite signal and the base potential of the transistor 22 go high, and the transistor 22 is put in OFF state, and the output terminal 28 goes low. Also, in the vibrating gyroscope 1, in the case of an abnormal state where the connection line from the piezoelectric element 4 to the oscillation circuit 5 is disconnected or short-circuited, or both connection lines from the phase-shifting circuit 6 to the piezoelectric elements 3a and 3b are disconnected or short-circuited, oscillation cannot be maintained, and as shown in Fig. 5, no oscillation signal is obtainable. Also, in this case, the potential of the composite signal and the base potential of the transistor 22 go high, and the transistor 22 is put in OFF state, and the output terminal 28 goes low. Accordingly, the detecting circuit 10 can detect an abnormal state of the vibrating gyroscope 1 by the level of the output terminal 28 or ON/OFF state of the transistor 22. Furthermore, in the detecting circuit 10 of the embodiment, also in the case where the oscillation circuit 5, the differential amplifier circuit 7 of the vibrating gyroscope 1 connecting it, the power source or the detecting circuit 10 is disconnected, the transistor 22 is put in OFF state, and the output terminal 28 goes low, and therefore these disconnections can also be detected. In addition, in the above-described embodiment, the oscillation signal of the vibrating gyroscope is rectified in the forward direction of the transistor, and the detection signal of the vibrating gyroscope is rectified in the direction reverse to the transistor, but in reverse, it is also possible that the detection signal of the vibrating gyroscope is rectified in the forward direction of the transistor, and the oscillation signal of the vibrating gyroscope is rectified in the direction reverse to the transistor. Thus, the ON/OFF state of the transistor of the detecting circuit is reversed and the level of the output terminal thereof is also reversed in normal state and an abnormal state, and an abnormal state of the vibrating gyroscope can be detected from the level of the output terminal or the ON/OFF state of the transistor. Also, in the above-described embodiment, a PNP transistor is used as a switching device, but an NPN transistor may be used in place of a PNP transistor. Also in this case, the ON/OFF state of the transistor and the level of the output terminal in normal state and an abnormal state of the vibrating gyroscope are reversed respectively, an abnormal state of the vibrating gyroscope can be detected from the level of the output terminal or the state of the transistor. Although an embodiment of 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 scope of the present invention being limited only by the terms of the appended claims. | A detecting circuit (10) for detecting an abnormal state in a vibrating gyroscope (1) which generates an oscillation signal (5a) for driving a vibrator (2) and a detection signal (7a) for detecting a rotational angular velocity of said vibrator, comprising: a first rectifying means (16a) for rectifying said oscillation signal (5a); a second rectifying means (16b) for rectifying said detection signal (7a) in the direction reverse to said oscillation signal rectified by said first rectifying means; a composite means (20a, 20b) for composing said oscillation signal rectified by said first rectifying means and said detection signal rectified by said second rectifying means; and a switching device (22) which is switched by a composite signal composed by said composite means. A detecting circuit in accordance with claim 1, wherein said first rectifying means (16a) comprises a diode. A detecting circuit in accordance with claim 1, wherein said second rectifying means (16b) comprises a diode. A detecting circuit in accordance with claim 1, wherein said composite means (20a, 20b) comprises a plurality of resistors connected in series. A detecting circuit in accordance with claim 1, wherein said switching device (22) comprises a transistor. A detecting circuit in accordance with claim 5, wherein said transistor (22) comprises a PNP transistor. A detecting circuit in accordance with claim 5, wherein said transistor (22) comprises an NPN transistor. | MURATA MANUFACTURING CO; MURATA MANUFACTURING CO., LTD. | MORI AKIRA; NAKAMURA TAKESHI; MORI, AKIRA; NAKAMURA, TAKESHI |
EP-0490249-B1 | 490,249 | EP | B1 | EN | 19,950,315 | 1,992 | 20,100,220 | new | C07K14 | C12P21, C07K1 | C07K14, C12P21, A61P5, A61K31, A61K38 | M07K209:00, C12P 21/02, C07K 14/60 | Process for the enzymatic preparation of GRF(1-44)NH2 | GRF(1-44)-NH₂ is prepared by the trypsin catalyzed enzymatic coupling of Leu-NH₂ to GRF(1-43)-OH. The latter compound may be obtained by recombinant DNA synthesis. Thus the present method provides an economical way to obtain the clinically important GRF(1-44)-NH₂. | Growth in animals is believed to be regulated by a cascade of bio-regulatory molecules. The hypothalamus produces a substance called Growth Hormone Releasing Factor (GRF) which in turn acts upon the pituitary to cause release of growth hormone (GH). GH stimulates the secretion of insulin growth factor (IGF) from the liver and other peripheral organs which binds to various cellular receptors stimulating the events required for linear growth. The pituitary is maintained under negative feedback control by somatostatin and IGF. GRF has been found to be enormously active and capable of stimulating the release of microgram per ml. levels of growth hormone in the blood. GRF can be utilized therapeutically in most of the areas now considered candidates for treatment by growth hormone, for example treatment of pituitary dwarfism, diabetes resulting from growth hormone production, enhancement of wound healing, treatment of burns or retardation of aging process. The successful isolation of GRF was due partly to the discovery that pancreatic tumors associated with acromegaly ectopically produced large quantities of GRF. Three forms of GRF, consisting of peptides homologous from the amino-terminus of 44,40 and 37 amino acids, were isolated by Guillemin et al [Science 218, 585-587 (1982)] and Rivier et al [Nature, 300, 276-278 (1982)]. The 44 amino acid amidated form of GRF, is considered to be the parent molecule and exhibits the full intrinsic activity and highest potency of the aforesaid forms of this molecule. The amidated carboxy-terminus is a key structural requirement for this high level of activity as the corresponding free acid (GRF(1-40)-OH) has a substantially lower level of activity. This is an important factor in developing low cost processes to produce these clinically important molecules. Thus, since amidation of recombinant DNA produced peptides have not previously been possible by methods which could be conveniently employed in high yield steps, the preparation of the desired product, GRF(1-44)-NH2, could previously be made only by use of conventional solid phase or solution phase peptide synthesis methods. The preparation of such a large peptide by these methods still represents a formidable technical challenge and the cost of production remains relatively high. It is well recognized in the art that peptides can be produced in large scale and at lowest cost by employing recombinant DNA technology. Thus, it would be an important development in the commercialization of GRF(1-44)-NH₂ to be able to use a recombinantly produced peptide as substrate for the introduction of the amide functionality. The instant invention is based on the discovery that GRF(1-44)-NH₂ can be conveniently prepared in good yield using GRF(1-43)-OH as the starting material. The latter compound can be produced by known recombinant DNA methods available to the art. Conversion of GRF(1-43)-OH to the desired product, GRF(1-44)-NH₂, is readily accompanied by the trypsin catalyzed coupling of -Leu-NH₂ to GRF(1-43)-OH in accordance with the process of the present invention. Trypsin is well known in the art to catalyze the transpeptidation of peptides which contain carboxy-terminus arginine or lysine [J. Markussen, Human Insulin by Transpeptidation of Porcine Insulin and Biosynthetic Precursors , MTP Press, Ltd., Boston (1987); H. Tsuzuti et al, J. Biochem., 88, 669-675 (1980); and L. Riechmann and V. Kasche, Biochemica et Biophysica Acta, 830, 164 (1985)]. The product, GRF-(1-44)-NH2, can be readily isolated from the reaction media after quenching with acetic acid by use of peptide purification methods known in the art, most preferably by HPLC followed by desalting in a manner known per se. The process of the present invention can be conveniently carried out by preparing a reaction mixture containing a solution of trypsin and Leu-NH₂ to which is added GRF(1-43)-OH, preferably obtained by recombinant DNA synthesis. The solvent employed for the present invention can be any solvent utilized in trypsin catalysis and is compatible with peptide synthesis. A preferred solvent for the purposes pf the invention is dimethylacetamide (DMAC). Preferably, the Leu-NH₂ solution is prepared by dissolving a Leu-NH₂ mineral acid salt (e.g. HCl) in water, adding dilute base (e.g. NaOH) to pH 8.0, lyophilizing and taking up the residue in the desired reaction solvent e.g. DMAC. Similarly, the trypsin solution can be conveniently prepared by dissolving trypsin in dilute aqueous CaCl₂ (0.1M). The trypsin and Leu-NH₂ solutions are mixed (25:75 v/v) and the reaction started by addition of GRF(1-43)-OH. The reaction can be conveniently carried out at room temperature. Conversion of the starting compound to the desired end product can be conveniently followed by removing aliquots from the reaction mixture, diluting with acetic acid to quench the reaction, and then applying the solution to an HPLC column. Usually the reaction is complete in about 3.5 hours. The reaction mixture is quenched by the addition of glacial acetic acid and diluting with water. Fractionation on HPLC (e.g. Lichrosorb RP-8 column) followed by desalting (e.g. Waters µBondapak C-18 column) and lyophilization provides the purified product, GRF (1-44)-NH₂, in good yield. The present invention will be illustrated in a preferred embodiment in the following example which is set forth for the purpose of illustration only. Example 1All amino acid derivatives were of the L-configuration and purchased from Bachem (Torrance, CA USA). Porcine trypsin Sigma Type IX (Sigma, Chemical Company, St. Louis, MO, USA) was assayed against Nα benzoyl-L-arginine ethyl ester (BAEE) and the specific activity determined to be 1.85 x 10⁴ U/mg. It was treated with N-tosyl-L-phenylalaninechloromethylketone (TPCK) [G. Schoellman and E. Shaw, Biochemistry, 2, 252 (1983)] and dialyzed extensively against distilled water and lyophilized to give 2.02 x 10⁴ U/mg. N,N-Dimethylacetamide (Kodak, Spectro Grade) and 1,4-butanediol (Sigma, Gold Label) were dried over 3A sieves. Tryptic digests were carried out in solutions of the peptide (1 mg/mL) and bovine trypsin (Millipore, Bedford, MA, USA 0.1 mg/mL) in 0.5M NH₄HCO₃ (pH 8.0) for 20 hours. All pH measurements were made with a glass electrode. In vitro bioassays were done in rat pituitary cell cultures and using a specific rat growth hormone radioimmunoassay as previously described (P. Brazeau et al., Proc. Natl. Acad. Sci. USA 79, 7909 (1982). GRF(1-43)-OH was prepared by solid-phase synthesis as follows: Boc-Leu-phenylacetamidomethyl (PAM)-resin (4.0 g, 0.33 mmol/g, 1.32 mmol) was introduced into two 50 mL reaction vessels and solid phase peptide synthesis was carried out by the BOP procedure [A. Fournier, C.-T. Wang, and A. M. Felix, Int. J. Peptide Protein Res., 31, 86-97, (1988)]. The couplings were performed using the in situ neutralization coupling protocol [D. Le-Nguyen, A. Hertz, and B. Castro, J. Chem. Soc. Perkin Trans. 1, 1915-1919, (1987)] for a total of 42 cycles to give 5.3 g of protected GRF(1-43)-PAM resin. A 1 g portion of the peptide-resin was treated with anhydrous HF (containing ca. 23% n-propanethiol) for 2 hr. at 0°C, evaporated at 0°C (high vac; CaO trap), triturated with EtOAc and extracted with TFA and filtered. The filtrate was evaporated and the residue dried to give 421 mg of crude GRF(1-43)-OH. The crude peptide was dissolved in 25 mL of 0.5% TFA/H₂O, filtered (0.45 µ Type HA Millipore filter) and loaded onto a Dupont Pro-10 C-8 column (2.2 x 25 cm). The column was eluted with (A) H₂O (0.5% TFA) - (B) CH₃CN (0.25% TFA) in a linear gradient from 20% (B) to 45% (B) in 60 min with a flow rate of 21 mL/min. Fractions were collected (1 min/fraction) and aliquots analyzed by the analytical HPLC system: Column: Lichrosorb RP-8 (5m); (A) 0.1M HClO₄ (pH 2.5) - (B) CH₃CN; 40% (B) to 60% (B) in 20 min at 1 mL/min; 0.2 AUFS; 206 nm. The product emerged in fraction 70 which was evaporated and lyophilized to give 17 mg of material. The product was shown to be homogenous by analytical HPLC and gave the expected amino acid composition after acid hydrolysis (Amino Acid Anal: 6N HCl; 110°C; 24 h): Asp, 4.09 (4); Thr, 0.91 (1); Ser, 3.96 (4); Glu, 7.78 (7); Gly, 3.11 (3); Ala, 4.82 (5); Val, 0.95 (1); Met 1.03 (1); Ile, 1.76 (2); Leu, 4.29 (4); Tyr, 1.80 (2); Phe, 0.82 (1); Lys, 2.15 (2); Arg, 6.06 (6). Confirmation of structure was provided by FAB mass spectrometry. Calcd.:(M+H)⁺, 4928.5 Found, 4928.5. Example 2A. 1.25M solution of Leu-NH₂ in DMAC was prepared by dissolving Leu-NH₂·HCl(1.33g, 7.98 mmol) in 5.0 mL of water, titrating to pH 8.0 with 1M NaOH, lyophilizing, and taking up the residue in 6.4 ml of DMAC. The NaCl precipitate was removed by filtering through a fine glass frit to give a clear solution of pH 9.25. A solution of trypsin (14.5 µM) and Leu-NH₂ (0.95 M) in 76:24 (v:v) DMAC/H₂O (pH 8.3) was prepared by dissolving trypsin (0.205 mg, 8.72 mmol) in 0.1M CaCl₂ (300 µL) followed by addition of the above 1.25M Leu-NH₂ in DMAC (950 µL). GRF(1-43)-OH (5.15 mg, 0.864 µmol) was dissolved in 0.600 mL of the above enzyme preparation and kept at room temperature (ca. 22°C). The progress of the reaction was monitored by removing 1 mL aliquots (16 µL total), diluting in 200 µL portions of 20% acetic acid, and applying to the HPLC column. The reaction was halted at the 3.5 hr mark by adding glacial acetic acid (0.20 mL) and diluting to 2.4 mL with water. The yield at this point was 60% as determined by analytical HPLC. A small portion (5 mL) of the reaction mixture was set aside for further monitoring before quenching with acetic acid. The reaction mixture was purified as follows: Analytical and preparative HPLC were carried out on a Lichrosorb RP-8 (5µ) column (0.4 x 25 cm). Eluants: (A) 0.1M NaClO₄ (pH 2.5) - (B) CH₃CN. The flow rate was 1.5 mL/min and gradients of 38 - 41% (B) in 10 min and 31 - 35% (B) in 90 min were employed for the analytical and preparative runs, respectively. Fractions from the Lichrosorb RP-8 column were desalted on a Waters µBondapak C-18 column (0.4 x 30 cm). Eluants: (A) H₂O (0.025% TFA) - (B) CH₃CN (0.025% TFA) and a flow rate of 2.0 mL/min was used. The sample was loaded and the column washed with 15% (B) for 20 min and the column eluted using a gradient of 15-40% (B) in 20 min. and the product-containing fractions were pooled and lyophilized. The final yield of GRF(1-44)-NH₂ was 1.95 mg (0.322 µmol, 37%). FAB-MS: (M+H)⁺ Calc: 5040.7, Found: 5040.5. Amino Acid Anal (6M HCl; 110°C, 72 h.): Asp, 4.12(4); Thr, 0.97(1); Ser, 3.65(4); Glu, 7.54(7); Gly, 2.99(3); Ala, 5.27(5); Val, 1.04(1); Met, 0.92(1); Ile, 2.01(2); Leu, 5.13(5); Tyr, 1.87(2); Phe, 0.91(1); Lys, 2.03(2); Arg, 5.54(6). In vitro biological potency: 0.92 ± 0.22. [rat pituitary in vitro bioassay in which the potency of GRF (1-44)-NH₂ is 1.00]. Tryptic mapping, by analytical HPLC, was identical to that of a chemically synthesized standard of GRF(1-44)-NH₂. | A process for the preparation of GRF(1-44)-NH₂ which process comprises reacting GRF(1-43)-OH with Leu-NH₂ in the presence of catalytic amounts of trypsin and isolating GRF(1-44)-NH₂ from the reaction mixture. The process of claim 1 wherein the reaction is carried out in a solution of dimethylacetamide. The process of claim 1 wherein the reaction is carried out at room temperature. The process of claim 1 wherein the reaction mixture is quenched after completion of the reaction by mixing with acetic acid. The process of claim 1 wherein said GRF(1-44)-NH₂ is isolated by use of HPLC. The process of claim 6 wherein said GRF(1-44)-NH₂ is desalted and lyophilized after HPLC isolation. | HOFFMANN LA ROCHE; F. HOFFMANN-LA ROCHE AG | FELIX ARTHUR MARTIN; HEIMER EDGAR PHILIP; FELIX, ARTHUR MARTIN; HEIMER, EDGAR PHILIP |
EP-0490253-B1 | 490,253 | EP | B1 | EN | 19,960,306 | 1,992 | 20,100,220 | new | G03G9 | C08K5, C09B35 | C09B35, C08K5, G03G9 | C08K 5/23B, C09B 35/21, G03G 9/09D2 | Magenta toner for developing electrostatic images | A magenta toner for developing electrostatic images which comprises a resin and at least one kind of the dis-azo dye represented by the following formula [I]: wherein X represents methyl group, ethyl group or alkoxy group having 1 to 4 carbon atoms; Y represents hydrogen atom or methyl group; R¹ and R² independently represent hydrogen atom, alkyl group, alkoxy group or halogen atom; Q and Q' represent naphthol AS residue. This magenta toner is good in transparency, color fastness to light, heat resistance, bleeding resistance and spectral property and offers good color reproduction as a toner for full-color images. A colored resin, a colored molded resin member and a color filter dyed with at least one kind of the dis-azo dye represented by Formula [I]. These are good in color fastness to light, bleeding resistance, heat resistance, transparency, spectral property and durability. | The present invention relates to a magenta toner powder for developing electrostatic images used for electrophotography, electrostatic recording, electrostatic printing and other purposes, with a red dis-azo dye having the triphenylmethane structure. In recent years, there have been increasing demands for color toners which offer images of various desired colors as necessary with the diversification of purpose of use of copying machines and printing machines, etc. So-called three primary color toners, which offer yellow, magenta and cyan colors, respectively, are important in obtaining full-color images. This kind of color toners basically comprise a toner resin and a coloring agent. To improve toner chargeability, a light-colored or colorless charge control agent providing a positive or negative charge is often added. When this toner is used as a two-component developing agent, the electrostatic latent image formed on a photoreceptor by charging and the exposure is made visible by developing it with the toner charged together mixing with a carrier and transferring the resulting toner image onto transfer paper or another transferee. To obtain a full-color image by superposing toner images of yellow, magenta and cyan colors, the three subtractive primaries, using such toners for color electrophotography etc., each toner is required to have a good spectral property and transparency for color reproduction. Transparency is also required in toners used for color electrophotography for overhead projectors (hereinafter referred to as OHP). It should also be noted that these toners are required not to be prone to discoloration, fading or bleeding due to light or heat. Organic pigments are generally most often used as coloring agents for color toners. However, most organic pigments are unsuitable for imparting a color to toners to yield color toners which are required to be transparent in superposing development because they are incompatible with binder resin. A number of means have been proposed to meet such requirements as far as possible. For example, Japanese Patent Unexamined Publication No. 295069/1987 discloses color toners incorporating various oil-soluble dyes or dispersion dyes; Japanese Patent Unexamined Publication No. 15555/1987 discloses a magenta toner incorporating a Rhodamine dye; Japanese Patent Unexamined Publication No. 217465/1989 discloses a magenta toner incorporating an anthraquinone dispersion dye. However, color toners incorporating an oil-soluble dye or dispersion dye which is soluble in resin can cause copied image quality deterioration during long term repeated use, thus posing a problem to be solved. DE 32 20 772 A1 relates to a photoreceptor for electrophotography. The electro photographic photoreceptor incorporates a disazo pigment suitable for use as a charge generation material for the light-sensitive layer. A disazo pigment having triphenylmethane structure is shown as a photoreceptor, i.e. OPC (organic photoconductor), used for example in photosensitive drums in copying machines. It is an object of the present invention to provide a magenta toner for developing electrostatic images which is good in transparency, color fastness to light, heat resistance, bleeding resistance and spectral property and which offers good color reproduction as a toner for full-color images. As a means for accomplishing the object described above, the magenta toner for developing electrostatic images of the present invention comprises a resin and at least one kind of the dis-azo dye represented by the following formula [I]: wherein X represents methyl group, ethyl group or alkoxy group having 1 to 4 carbon atoms; Y represents hydrogen atom or methyl group; R¹ and R² independently represent hydrogen atom, alkyl group, alkoxy group or halogen atom; Q and Q' represent naphthol AS residue. This magenta toner for developing electrostatic images is good in transparency, color fastness to light, heat resistance, bleeding resistance and spectral property, offers good color reproduction as a toner for full-color images and yield good copied images even in long term repeated use. Also, the magenta toner for developing electrostatic images incorporates at least one kind of the dis-azo dye represented by Formula [I] above, a binder resin and a charge control agent, wherein said binder resin and charge control agent are substantially colorless. Incorporating the substantially colorless binder resin and charge control agent, this magenta toner for developing electrostatic images is not prone to cause tone degradation in toner images and is capable of offering a uniform and stable triboelectrical chargeability even when it is used continuously or under changing conditions. The magenta toner for developing electrostatic images of the present invention may also comprise a composition obtained by polymerizing a polymerizable composition containing a polymerizable monomer and at least one kind of the dis-azo dye represented by Formula [I] in the presence of a polymerization initiator. This toner has still better transparency and permits better color reproduction as a toner for full-color images. Figure 1 shows the near ultraviolet-visible light absorption spectrum of Example Dye 1. Figure 2 shows the near ultraviolet-visible light absorption spectrum of Example Dye 3. Figure 3 shows the near ultraviolet-visible light absorption spectrum of Example Dye 9. Figure 4 shows the near ultraviolet-visible light absorption spectrum of Example Dye 10. The dye represented by Formula [I] for the present invention can be synthesized as follows: First, an aniline (A) and a benzaldehyde (B) are condensed to a compound (C), which is then tetrazotized and coupled with a naphthol AS to yield the dye represented by Formula [I]. With respect to the above formulas (A), (B) and (C), X, Y, R¹ and R² have the same definitions as in Formula [I]. X represents methyl group, ethyl group or an alkoxy group having 1 to 4 carbon atoms such as methoxy, ethoxy, propoxy or butoxy; Y represents hydrogen atom or methyl group; R¹ and R² independently represent hydrogen atom, alkyl group such as methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl, sec-butyl, tert-butyl, amyl or iso-amyl, alkoxy group such as methoxy, ethoxy, propoxy or butoxy or atom of halogen such as chlorine, bromine or iodine. With respect to Formula [I], Q and Q' are naphthol AS residues represented by the following formulas 1 ○ through 4 ○, and Q and Q' may be identical or not. With respect to Formula 1 ○, n represents an integer of 0 to 3; (R³)n represents no substituent or one, two or three substituent(s); each R³ substituent independently represent alkyl group such as methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl, sec-butyl, tert-butyl, amyl or iso-amyl, alkoxy group such as methoxy, ethoxy, propoxy or butoxy, atom of halogen such as chlorine, bromine or iodine or a nitro group. With respect to Formula 4 ○, R⁴ represents alkyl group such as methyl, ethyl, propyl, iso-propyl, butyl, iso-butyl, sec-butyl, tert-butyl, amyl or iso-amyl or hydroxyalkyl group such as hydroxymethyl, α-hydroxyetlhyl, β-hydroxyethyl, hydroxypropyl, hydroxybutyl or hydroxyamyl. Naphthol AS compounds are exemplified by the following compounds (a) through (k), all of which are commercially available. (a) Naphthol AS (b) Naphthol AS-D (c) Naphthol AS-RL (d) Naphthol AS-OL (e) Naphthol AS-PH (f) Naphthol AS-E (g) Naphthol AS-TR (h) Naphthol AS-BO (i) Naphthol AS-SW (j) Naphthol AS-BS (k) Naphthol BD-1 Examples of the dye represented by Formula [I] for the present invention are given in Table 1. Example Dye Number Aniline component Benzaldehyde component Coupler component λ max (nm) X Y R¹ R² Q Q' 1CH₃CH₃HHbb522 558 2CH₃CH₃HHcc522 556 3CH₃CH₃HHee520 554 4CH₃CH₃HHaa522 556 5CH₃HHHaa516 548 6OCH₃HHHaa530 560 7CH₃H CH₃ (para) CH₃ (ortho) b b520 540 8OCH₃HC₂H₅ (para)Hcc526 556 9CH₃Hi-C₄H₉(para)Hhh520 556 10CH₃CH₃OCH₃ (para)Hcc522 556 11CH₃CH₃i-C₄H₉ (para)Hff524 558 12CH₃HC₂H₅ (para)Hgg516 552 13CH₃HHC1 (ortho)ff520 552 14CH₃CH₃HHab522 558 15OCH₃HOCH₃ (para)Hcc528 560 16CH₃CH₃HHjj526 562 17CH₃CH₃HHkk512 544 In Table 1, λ max shows the maximum value of visible light absorption wavelength of each example dye determined in chloroform solvent using the 8451A Diode Array Spectrophotometer (trade name, produced by Hewlett-Packard). The near ultraviolet-visible absorption spectra of Example Dyes 1, 3, 9 and 10 determined in the same manner as above are shown in Figures 1, 2, 3 and 4, respectively. In Figures 1 through 4, the abscissa indicates wavelength and the ordinate indicates absorbance. The magenta toner for developing electrostatic images of the present invention can incorporate almost any conventional toner resin or binder resin. The toner resin or binder resin which is preferably used for the present invention is required to be transparent, substantially colorless (colored to such extent that toner images do not undergo tone deterioration), capable of dissolving or melt-mixing the dis-azo dye represented by Formula [I] for the present invention and positively or negatively chargeable per se or by the addition of a charge control agent, to become fluid under appropriate heat or pressure conditions and to be finely pulverizable. Examples of such resins which can be preferably used include polystyrene resin, acryl and acrylic resins, styrene-(meth)acrylate copolymer, styrene-methacrylate copolymer and polyester resin. Other usable resins include epoxy resin, polyamide resin, polyvinylal resin, polyethylene resin, polypropylene resin and polyolefin. These resins may be used singly or in combination of two or more kinds. The magenta toner for developing electrostatic images of the present invention may contain a positively or negatively charging charge control agent to improve its chargeability. The charge control agent is preferably substantially colorless. Here, substantially colorless means that the color is such that toner images do not undergo tone deterioration. Charge control agents which can be preferably used for negatively chargeable toners to provide a negative charge are metal complexes of aromatic o-oxycarboxylic acid, metal complexes of aromatic o-aminocarboxylic acid and metal complexes of aromatic dicarboxylic acid. Examples of such metal complexes include the metal complexes of salicylic acid or alkyl salicylic acid disclosed in Japanese Patent Examined Publication No. 42752/1980 (e.g., chromium complex of 3,5-di-tertiary-butylsalicylic acid, chromium complex of salicylic acid), the zinc complexes of aromatic o-oxycarboxylic acid disclosed in Japanese Patent Unexamined Publication No. 69073/1986 (e.g., zinc complex of 3,5-di-tertiary-butylsalicylic acid, zinc complex of oxynaphthoic acid), the aluminum complexes of aromatico-oxycarboxylic acid and aluminum complexes of aromatic o-aminocarboxylic acid disclosed in Japanese Patent Unexamined Publication Nos. 208865/1988 and 105262/1989, and the chromium or zinc complexes of aromatic dicarboxylic aciddisclosed in Japanese Patent Unexamined Publication No. 73963/1986. Positively charging charge control agents which can be preferably used for positively chargeable toners are quaternary ammonium salt compounds and polyamine compounds. Examples of such charge control agents include the quaternary ammonium salt compounds disclosed in US Patent No. 4,654,175 and Japanese Patent Examined Publication No. 54694/1989 and the polyamine resin disclosed in Japanese Patent Examined Publication No. 13284/1978. This kind of charge control agents are commercially available under trade names of Bontron E-81, Bontron E-84, Bontron E-88, Bontron P-51 and Bontron P-52 (trade names, produced by Orient Chemical Industries Ltd.). Examples of polymerizable monomers used in the magenta toner for developing electrostatic images described above include vinyl aromatic monomers such as styrene and methylstyrene, acrylic monomers such as methyl acrylate, ethyl acrylate, phenyl acrylate, methyl methacrylate, butyl methacrylate, 2-ethylhexyl methacrylate and ethyl -hydroxyacrylate, vinyl esters such as vinyl acetate and vinyl propionate, vinyl ethers such as vinyl-n-butyl ether and vinylphenyl ether and unsaturated monoolefins such as ethylene and propylene. Examples of polymerization initiators which can be used for this magenta toner for developing electrostatic images include azo type initiators such as 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile and 2-t-butylazo-2-cyanopropane and peroxide type initiators such as t-butyl hydroperoxide, di-t-butyl peroxide and benzoyl peroxide. Although any method of polymerization can be used to polymerize the polymerizable composition described above, solution polymerization, suspension polymerization, mass polymerization, etc. are practically useful. The toner of the present invention preferably contains the dis-azo dye represented by Formula [I] in an amount of 0.5 to 10 parts by weight, more preferably 1 to 5 parts by weight per 100 parts by weight of resin or binder resin. The content of the dis-azo dye represented by Formula [I] in the polymerizable composition described above is preferably 10 to 20% by weight. With respect to the toner of the present invention when it comprises a composition obtained by polymerizing this polymerizable composition, the content of the polymeric composition is preferably 2 to 50 parts by weight, more preferably 5 to 20 parts by weight per 100 parts by weight of resin or binder resin. The toner of the present invention may incorporate one or more other coloring agents, as long as the purpose or effect thereof is not interfered with. The amount of charge control agent is preferably 0.1 to 10 parts by weight, more preferably 0.5 to 5 parts by weight per 100 parts by weight of toner resin or binder resin. To improve toner quality, it is preferable to internally or externally add one or more additives other than the charge control agent, such as a fluidity improving agent and image peeling preventing agent. The magenta toner for developing electrostatic images of the present invention is, for example, produced as follows: A toner of 5 to 20 µm in average particle size can be obtained by thoroughly mixing the dis-azo dye represented by Formula [I] or the above-mentioned polymeric compositioIn containing the dye, a resin or binder resin, a chrarge control agent and, if necessary, a magnetic material, a fluidizing agent and other additives using a ball mill or another mechanical mixer, subsequently kneading the mixture in a molten state using a hot kneader such as a heat roll, kneader or extruder, cooling and solidifying the mixture, and then pulverizing the mixture and classifying the particles. Other usable methods include the method in which the starting material is dispersed in binder resin solution and then spray dried, and the polymerizing toner production method in which a given set of materials are mixed in a monomer for binder resin to yield an emulsified suspension which is then polymerized to yield the desired toner (e.g., the methods described in Japanese Patent Unexamined Publication Nos. 260461/1989 and 32365/1990. When using the toner of the present invention as a two-component developer, development can be achieved by the two-component magnetic brush developing process and other processes using the toner in mixture with carrier powder. Any known carrier can be used. Examples of the carrier include iron powder, nickel powder, ferrite powder arid glass beads of about 50 to 200 µm in particle size, and such materials as coated with acrylate copolymer, styrene-acrylate copolymer, styrene-methacrylate copolymer, silicone resin, polyamide resin, ethylene fluoride resin or the like. When using the toner of the present invention as a single-component developer, a small amount of finely divided magnetic powder of ferromagnetic material such as iron powder, nickel powder or ferrite powder may be added and dispersed upon preparing the toner as described above. Examples of developing processes which can be used in this case include contact development and jumping development. ExamplesThe present invention is hereinafter described in more detail by means of the following examples, but these are not to be construed as limitative on the present invention. In the description below, part(s) by weight are referred to as part(s) for short. Examples of synthesis of dis-azo dye for the present inventionSynthesis of 4,4'-benzylidene-di-2,5-xylidineA mixture of 121 g (1 mol) of 2,5-xylidine, 53 g (0.5 mol) of benzaldehyde, 70 g of concentrate hydrochloric acid and 150 g of chlorobenzene was reacted while refluxing for 7 hours. After being alkalized in an aqueous solution of caustic soda, the reaction mixture was subjected to steam distillation, followed by residue filtration. The solid separated by filtration was washed with water and dried to yield 130 g of an unpurified base compound. This compound was purified with an about 3-fold amount of alcohol to yield a white powder represented by the following structural formula. Its melting point was 203 to 205 °C. Synthesis of Example Dye 18.3 g of 4,4'-benzylidene-di-2,5-xylidine was dissolved and dispersed in 80 g of water containing 12 g of concentrate hydrochloric acid. After cooling the solution to under 5 °C, a solution of 7 g of sodium nitrite in a small amount of water was dropwise added thereto for tetrazotization. Separately, 13.6 g of naphthol AS-D was dissolved in 200 g of water containing 4.5 g of caustic soda. To this solution, 1 g of a nonionic dispersing agent was added, followed by addition of ice to cool the mixture to under 5 °C to yield a coupler solution. To this coupler solution, the tetrazonium salt solution prepared above was dropwise added for coupling. The resulting crystal was separated by filtration, washed with water and dried to yield 22.5 g of a red powder of dye (Example Dye 1). Synthesis of Example Dye 119.7 g of 4,4'-(p-isobutylbenzylidene)-di-2,5-xylidine was dissolved in 100 g of acetic acid. To this solution, 10 g of concentrate hydrochloric acid was added. After cooling the solution to under 5 °C, a solution of 3.5 g of sodium nitrite in a small amount of water was dropwise added thereto for tetrazotization. 14.9 g of naphthol AS-E was dissolved in 100 g of DMF. To this solution, 2 g of a nonionic surfactant was added, followed by cooling to under 10 °C to yield a coupler solution. While keeping the coupler solution alkaline by dropwise addition of a dilute aqueous solution of caustic soda, the tetrazonium salt solution prepared above was dropwise added thereto for coupling. The resulting crystal was separated by filtration, washed with water and dried to yield 25 g of a red powder of dye (Example Dye 11). Examples of preparation of polymeric compositionPreparation of Polymeric Composition 1140 parts of styrene, 60 parts of n-butyl methacrylate, 50 parts of hydroxyethyl methacrylate, 30 parts of Example Dye 1 and 300 parts of toluene were placed in a three-necked flask equipped with a reflex condenser, and 2 parts of azoisobutyronitrile was added, followed by polymerization at 85 to 100 °C for 10 hours. After completion of the reaction , the unreacted monomer and toluene were removed to yield Polymeric Composition 1. Preparation of Polymeric Composition 2100 parts of styrene, 100 parts of n-butyl methacrylate, 50 parts of hydroxyethyl methacrylate, 50 parts of Example Dye 2 and 300 parts of toluene were placed in a three-necked flask equipped with a reflex condenser, and 5 parts of azoisobutyronitrile was added, followed by polymerization at 75 to 90 °C for 10 hours. After completion of the reaction, the unreacted monomer and toluene were removed to yield Polymeric Composition 2. Preparation of Polymeric Compositions 3 through 17Polymeric Compositions 3 through 17 were prepared in the same manner as in above Examples except that the dyes were replaced with Example Dyes 3 through 17 listed in Table 1 and the type and amount of polymerization initiator were varied as appropriate. Example 1Styrene-acryl copolymer [HIMER TB-1000 (trade name), produced by Sanyo Kasei Co., Ltd.].... 100 parts Example Dye 1.... 3 parts Charge control agent [Bontron E-84 (trade name), produced by Orient Chemical Industries Ltd.].... 1.5 parts Low polymer propylene [Biscal 550-P (trade name), produced by Sanyo Kasei Co., Ltd.].... 10 parts The above ingredients were uniformly pre-mixed using a high-speed mixer, and then kneaded in a molten state using an extruder, cooled, and roughly milled in a vibration mill. The obtained coarse product was finely pulverized using an air jet mill equipped with a classifier to obtain a fine powder of toner of 5 to 20 µm in particle size. 5 parts of this toner was admixed with 95 parts of a resin-coated iron powder carrier [F813-150 (trade name), produced by Nippon Teppun Co., Ltd.) to yield a developer. This developer was found to be -20.2 µ C/g in the amount of initial blowoff charges. The amounts of initial blowoff charges of this developer under low-temperature low-humidity conditions (5°C, 30% relative humidity) and high-temperature high-humidity conditions (35 °C, 90% relative humidity) were -20.3 µ C/g and -20.5 µ C/g, respectively, indicating very high stability. When this developer was used for a commercial copying machine (selenium drum type) to form toner images, fog-free very distinct glossy magenta color images were obtained. Even long term repeated use permitted the obtainment of stable copies free of quality degradation. Example 2Polyester [HP-301, produced by The Nippon Synthetic Chemical Industry, Co., Ltd.].... 100 parts Example Dye 6.... 3 parts Charge control agent [Bontron E-81 (trade name), produced by Orient Chemical Industries Ltd.].... 1.2 parts Low polymer propylene [Biscal 550-P (trade name), produced by Sanyo Kasei Co., Ltd.].... 10 parts The above ingredients were treated in the same manner as in Example 1 to yield a toner. Three parts of the obtained toner was admixed with 97 parts of an iron powder carrier [TEFV200/300 (trade name), produced by Nippon Teppun Co., Ltd.] to yield a developer. This developer was found to be -22.4 µ C/g in the amount of initial blowoff charges. When copies were taken in the same manner as in Example 1, this developer gave fog-free distinct magenta images with high thin-line reproducibility. Even long term repeated use permitted the obtainment of stable copies free of image quality degradation. Example 3Styrene-acryl copolymer [HIMER TB-1000 (trade name), produced by Sanyo Kasei Co., Ltd.].... 100 parts Polymeric Composition 1.... 15 parts Charge control agent [Bontron E-88 (trade name), produced by Orient Chemical Industries Ltd.].... 1 part Low polymer propylene [Biscal 550-P (trade name), produced by Sanyo Kasei Co., Ltd.].... 10 parts The above ingredients were treated in the same manner as in Example 1 to yield a toner. Three parts of the obtained toner was admixed with 97 parts of an iron powder carrier [TEFV200/300 (trade name), produced by Nippon Teppun Co., Ltd.] to yield a developer. This developer was found to be -20.2 µ C/g in the amount of initial blowoff charges. When the developer was used for a commercial color copying machine [produced by Canon Inc.] to take copies, fog-free very distinct magenta images were obtained. Even long term repeated use permitted the obtainment of stable copies free of image quality degradation. When images were formed using this developer on images formed using a yellow toner developer and images were formed thereon using a cyan toner developer, color images with good color reproduction were obtained. Example 4Styrene-acryl copolymer [HIMER TB-1000 (trade name), produced by Sanyo Kasei Co., Ltd.].... 100 parts Example Dye 11.... 2.5 parts Charge control agent [Bontron P-51 (trade name), produced by Orient Chemical Industries Ltd.].... 1.2 parts Low polymer propylene [Biscal 550-P (trade name), produced by Sanyo Kasei Co., Ltd.].... 10 parts The above ingredients were treated in the same manner as in Example 1 to yield a toner. Three parts of the obtained toner was admixed with 97 parts of an iron powder carrier [TEFV200/300 (trade name), produced by Nippon Teppun Co., Ltd.] to yield a developer. This developer was found to be +22.8 µ C/g in the amount of initial blowoff charges. When the developer was used for a commercial copying machine [Canon NP (trade name), produced by Canon Inc.] to take copies, fog-free very distinct magenta images were obtained. Even long term repeated use permitted the obtainment of stable copies free of image quality degradation. When copied images on an OHP sheet were projected on a screen using an OHP, images with distinct magenta color were obtained. Example 5Styrene-acryl copolymer [HIMER TB-1000 (trade name), produced by Sanyo Kasei Co., Ltd.].... 100 parts Example Dye 9.... 5 parts Iron sesquioxide (Fe₂O₃).... 15 parts Charge control agent [Bontron P-51 (trade name), produced by Orient Chemical Industries Ltd.].... 1 part Low polymer propylene [Biscal 550-P (trade name), produced by Sanyo Kasei Co., Ltd.].... 10 parts The above ingredients were uniformly pre-mixed using a ball mill to yield a premix, which was then kneaded in a molten state using a twin-screw extruder [PCM-30 (trade name), produced by Ikegai Seisakusho Co., Ltd.], cooled and thereafter roughly crushed, finely pulverized and classified to yield a single-component toner of 5 to 15 µm in particle size. When this toner was used for a commercial copying machine [NP-201 (trade name), produced by Canon Inc.] to form toner images, fog-free magenta images were obtained with high quality. Comparative Example 1A toner was prepared and used to form copied images in the same manner as in Example 1 except that the dis-azo dye used in Example 1 (Example Dye 1) was replaced with C. I. Solvent Red 22 (C.I. 21250). The initially obtained copied images had a distinct red color, but repeated copying for a long period resulted in uneven copying with color density degradation and fogging. Comparative Example 2A toner was prepared and used to form copied images in the same manner as in Example 1 except that the dis-azo dye used in Example 1 (Example Dye 1) was replaced with C. I. Pigment Red 61 (C.I. 24830:1). The initially obtained copied images had a distinct red color, but the image density was lower than that obtained in Example 1 and repeated copying for a long period resulted in uneven copying with color density degradation. Also, the images copied on an OHP sheet lacked transparency and were not suitable for use for OHP. | A magenta toner powder for developing electrostatic images which comprises a resin and at least one kind of the dis-azo dye represented by the following formula [I]: wherein X represents a methyl group, ethyl group or alkoxy group having 1 to 4 carbon atoms; Y represents a hydrogen atom or methyl group; R¹ and R² independently represent a hydrogen atom, alkyl group, alkoxy group or halogen atom; Q and Q' represent a naphthol AS residue represented by the following formulas 1 ○ through 4 ○ , and Q and Q' may be identical or not: where n =0-3 R³ =alkyl, alkoxy, halogen or nitro R⁴ =alkyl or hydroxyalkyl The magenta toner powder for developing electrocstatic images of claim 1 further comprising a charge control agent, wherein said binder resin and charge control agent are substantially colorless. The magenta toner powder for developing electrostatic images of claim 2 wherein said charge control agent is negatively charging charge control agent selected from the group consisting of metal complexes of aromatic o-oxycarboxylic acid, metal complexes of aromatic o-aminocarboxylic acid and metal complexes of aromatic dicarboxylic acid. The magenta toner powder for developing electrostatic images of claim 2 wherein said charge control agent is a positively charging charge control agent selected from the group consisting of quaternary ammonium salt compounds and polyamine compounds. The magenta toner powder for developing electrostatic images of one of claims 1 to 4 further comprising a polymeric composition of at least one kind of said dis azo dye represented by formula (I) and a polymer. | ORIENT CHEMICAL IND; ORIENT CHEMICAL INDUSTRIES, LTD. | OTSUKA MASAHIRO; OTSUKA, MASAHIRO; Otsuka, Masahiro, c/o Orient Chemical Ind. Ltd.Lab |
EP-0490258-B1 | 490,258 | EP | B1 | EN | 19,950,308 | 1,992 | 20,100,220 | new | C06B45 | C06B25 | C06B45, C06D5, C06B25 | C06B 25/18, C06B 45/10H | Stable plasticizers for nitrocellulose/nitroguanidine-type compositions | Stable plasticizer system and corresponding nitrocellulose/nitroguanidine nitramine-type propellant compositions utilizing such system. A mixture of a high energy nitratolkyl nitramine and a second nitrato alkyl nitramine having a lower energy content is used as plasticizer system. | The present invention relates to stable propellant compositions of low sensitivity comprising matter and energy adjustment/plasticizer components and corresponding method for improving storage life by utilizing a stable plasticizer system. Most conventional gun propellants comprise a matrix component such as nitrocellulose with various nitrate esters such as nitroglycerine, and/or nitroguanidine, such high energy compositions unfortunately, can be easily set off or initiated by neighboring explosions. One promising approach for developing less sensitive gun propellants has involved the use of high-energy nitraamines such as alkyl nitrato nitramines as substitutes for such sensitive esters in multi-based propellants. Nitraamines of such type, their substitution and preparation, are disclosed, for instance, in U.S. Patent 2,461,582 of Wright et al. and in U.S. Patent 2485855 of Blomquist et al., using ethanol-amine or N-alkyl substituted ethanol-amine and acetic anhydride as reactants. As noted in Blomquist, however, there is a tendency for high energy nitramines to migrate and crystallize out of nitrocellulose during storage, resulting in substantial unplanned changes in sensitivity and ballistic properties. This problem is dealt with by utilizing a propellant composition comprising A. a matrix component, such as nitrocellulose, and/or the like, B. an energy adjustment component; and C. an effective amount of plasticizer component capable of gelation of the matrix component and comprising (i) a high energy nitrato alkyl nitramine (i.e. based on heat of explosion) of the formula in which R is defined as a -Alk-O-NO₂, H, or a 1-2 carbon monovalent aliphatic group; and Alk is individually defined as a 1-2 carbon divalent aliphatic chain; said high energy alkyl nitramine being at least partly soluble or miscible in ii. a second nitrato alkyl nitramine having a lower energy content (i.e. heat of explosion) than the high energy nitramine component of Formula I and represented by the formula in which R' is individually defined as a 2-5 carbon monovalent aliphatic group of different molecular structure from the R group of formula I and n is a positive integer not exceeding about 2, the ratio of A./B./C. components of the propellant composition being 4-5/1-2/2-4 in parts by weight based on propellant composition, in the cumulative presence of up to about 6% by weight, based on propellant composition, of one or more conventional additive comprising a stabilizer such as ethyl centralite, an opacifier such as carbon black, a flash suppressant such as KNO₃ or K₂SO₄, and the like. For present purposes the ratio by weight of high energy nitrato alkyl nitramine-to-nitramine lower energy in the (C.) component is preferably 1-5 to 5-1 in parts by weight, and the R and R' substituent groups within formulae I and II are molecularly dissimilar in each plasticizer component. Of particular interest, for present purposes, is the use of normally solid high energy nitrato ethyl nitramine ingredients in which the definition of R in formula I is nitratoethyl or methyl, and Alk is -CH₂CH₂-, while the R' group (formula II) is preferably a 2 to 4 carbon monovalent alkyl group such as an ethyl, propyl or butyl substituent. The term matrix component for purposes of the present invention can include one or more of nitrocellulose, cellulose acetate, cellulose acetate butyrate, ethyl cellulose, ethyl acrylate-based polymer, and styrene-acrylate type copolymer. The term energy adjustment component, for present purposes, comprises generally insoluble energetic solids such as one or more of nitroguanidine, RDX, HMX and ethylene dinitramine (EDNA) and similar recognized components. The term effective amount , for purposes of the present invention, is defined as about 25%-65% by weight of binder component of the propellant composition (binder not including solids). Nitratoethyl nitramines of interest for purposes of formula I and II components along with pertinent, physical characteristics is set out in Tables I and II below, in which energy content of each component is set out as calculated heat of explosion in J/g (cal/gm). Cpd# Solubility Parameter 113.1 213.2 3(4)11.4 511.0 610.6 710.4 Example IA. A 22,68kg (50 lb.) batch of test propellant composition consisting of nitrocellulose (39.5 % by wt.), nitroguanidine (22.5%), ethyl centralite (1.5%), potassium sulfate (1%), carbon black (0.5%) and methyl nitrato ethyl nitramine derivative (35%) of the formula (obtained from methyl ethanolamine, nitric acid, and acetic anhydride in accordance with the process as described in col 4 of U.S. Patent 2,485,855) is prepared by initially blending nitrocellulose, ethyl centralite, potassium sulfate (1%) and carbon black in indicated amounts with a 50/50 acetone/ethanol solvent at ambient temperature at 25 rpm for about 10 minutes. To this is then added the methyl-nitratoethyl nitramine component premixed in 50/50 acetone/ethanol solvent, and the combined material blended for 1 hour to obtain a colloided nitrocellulose phase. Into this phase is slowly mixed dry nitroguanidine component and blended for about 1 hour, to obtain a homogeneous dough-like consistency. The dough is then put through a 10.16cm (4-inch) extrusion press having a plurality 1.143 cm of (.45 inch) diameter die holes to obtain correspondence extruded strands which are then conventionally cut into 1.524cm (0.6 ) lengths, air dried at room temperature for 1 day then subject to a 55 C long drying phase for 3 days. The resulting granular propellent is stored at ambient temperature and examined after 1 week. Observed results are reported in Table IV below. B. The process of IA, is repeated using 46.5 parts by weight of the methyl nitratoethyl nitramine mixed with 52.5 parts nitrocellulose and 1 part ethyl centralite stabilizer. No nitroguanidine was added. After drying and storage steps identical to Ex. 1A, the propellant is evaluated and results reported in Table IV below. C. The process of IA is repeated using 25 parts by weight of the methyl nitratoethyl nitramine mixed with 74 parts of nitrocellulose and 1 part of ethyl centralite. After drying and storage steps identical to Ex. 1A, the propellant is evaluated and results reported in Table IV below. D. The process of IA, is repeated except that the relative amounts and the type of insoluble, energetic solid are mixed as follows, with respect to nitrocellulose (16.1%), nitroguanidine (26.5%), cyclonite or RDX (47.9%), ethyl centralite (0.4%), carbon black (0.1%), KNO₃ (1%), the methyl nitratoethyl nitramine (4.6%) (cpd 2, Table I) and the ethyl nitratoethyl nitramine (3.4%) (cpd 4, Table II). The observed results are reported in Table IV below. E. The process of Ex. IB is repeated except that the relative amounts of ingredients are mixed as follows, with respect to nitrocellulose (47.8%), nitroguanidine (15%), ethyl centralite (1%), KNO₃ (1%), carbon black (0.2%), the methyl nitrato ethyl nitramine (20%) (cpd 2, Table 1) and the ethyl nitrato ethyl nitramine (10%) (Cpd 4 Table II). The observed results are reported in Table IV below. Example Observed Surface Crystallization 1A(++) 1B(++) 1C(+) 1D(-) 1E(-) | A propellant composition comprising, in combination, A. a matrix component; B. an energy adjustment component; and C. an effective amount of a plasticizer component capable of gelation of said matrix component and comprising i. a high energy nitratoalkyl nitramine of the formula in which R is defined as -Alk-O-NO₂, H, or a 1-2 carbon monovalent aliphatic group; and Alk is individually defined as a 1-2 carbon divalent aliphatic chain; said high energy alkyl nitrato-nitramine, being at least partly soluble or miscible in component II; and further comprising ii. a second nitrato alkyl nitramine having a lower energy content than said high energy nitrato alkyl nitramine component, and represented by the formula in which R' is individually defined as a 2-5 carbon monovalent aliphatic group of different molecular structure from the R group of formula (I) and n is defined as a positive integer not exceeding 2, the ratio of A./B./C. components of said propellant composition being 4-5/1-2/2-4 in parts by weight based on propellant composition, in the cumulative presence of up to 6% by weight, based on propellant composition, of one or more additive selected from the group consisting of a stabilizer an opacifier, and a flash suppressant. A propellant composition of claim 1 wherein the ratio by weight of said A./B./C. components is 4.5/1.5/2.0 based on propellant composition. A propellant composition of claim 1 wherein the ratio by weigh of A./B./C. components is 4.8/1.5/3.5, based on propellant composition. A propellant composition of claim 1, wherein the ratio by weight of A./B./C. components is 5.0/2.0/4.0 based on propellant composition. A propellant composition of claim 2, wherein the energy adjustment component is nitroguanidine and the matrix component is nitrocellulose. A propellant composition of claim 3, wherein the energy adjustment component is nitroguanidine and the matrix component is nitrocellulose. A propellant composition of claim 4, wherein the energy adjustment component is nitroguanidine and the matrix is nitrocellulose. A method for improving the storage life of double based low sensitivity propellant composition comprising a matrix component A, an energy adjustment component B and a nitratoalkyl nitramine plasticizer component C, the ratio of A/B/C components of said propellant composition being 4-5/1-2/2-4 in parts by weight based on propellant composition, comprising the steps of a) initially dissolving at least one high energy nitratoalkyl nitramine of the formula in which R is defined as -Alk-O-NO₂, H, or a 1-2 carbon monovalent aliphatic group, and Alk is individually defined as a 1-2 carbon divalent aliphatic chain; at least in part into a second nitrato alkyl nitramine component having a lower energy content than said nitramine of formula I and represented by the formula in which R' is defined as a 2-5 carbon monovalent aliphatic group of different molecular structure from the R group of said high energy nitramine component, and n is defined as a positive integer not exceeding 2; (b) admixing and blending the resulting combined plasticizer component into said matrix component to obtain a dough-like mixture; and (c) blending an energy adjustment component into said dough-like mixture to obtain an extrudable essentially homogeneous mass; (d) extruding said essentially homogeneous mass to obtain strands of propellant material and (e) cutting and drying said strands to obtain the desired propellant composition. The method of claim 8 wherein the matrix component is nitrocellulose and the ratio of high energy nitratoalkyl nitramine (formula I)-to-second nitramine (formula II) in said plasticizer component is 1-5 to 5-1. The method of claim 8 wherein the high energy nitramine of formula I and the second nitrato alkyl amine of formula II are initially dissolved in a common solvent system prior to blending into said matrix component. | HERCULES INC; HERCULES INCORPORATED | ZEIGLER EDWARD HAYS; ZEIGLER, EDWARD HAYS |
EP-0490260-B1 | 490,260 | EP | B1 | EN | 19,951,025 | 1,992 | 20,100,220 | new | B06B1 | H01L41 | B06B1, H04R17, H01L41 | B06B 1/06, H01L 41/18 | Ferroelectric ceramic transducer | A ferroelectric ceramic transducer having low density, high compliance and improved electrical properties achieved by the absence of any solid or liquid material in the spaces between the lateral sides of the ferroelectric ceramic posts of the transducer. The ceramic volume-fill of the posts is no greater than sixty percent. | Field of the InventionThis invention relates, in general, to ferroelectric devices and, in particular, to piezoelectric and relaxor ferroelectric transducers having application in ultrasound transmission and reception. Description of the Prior ArtU.S. 4,412,148 discloses a PZT-polymer composite fabricated so that an array of parallel PZT strands or rods are embedded in a mechanically compliant matrix of a polymer, such as an epoxy. U.S. 4,613,784 discloses a PZT glass polymer composite material of 1-2-3 connectivity made from a plurality of generally parallel PZT rods aligned in the direction of a poling electric field secured in the matrix of the polymer with glass fibers aligned both in a direction perpendicular to the PZT rods and in the third orthogonal direction. U.S. 4,683,396 discloses an ultrasonic transducer having a piezoelectric composite in which a number of piezoelectric ceramic poles are arranged in a plate-like polymer matrix perpendicular to the plate surface in which the volume ratio of the piezoelectric poles is in a range of 0.15 to 0.75 and the height of each pole is larger than the spacing between adjacent poles. U.S. 4,726,099 discloses a ceramic polymer matrix composition for use in piezoelectric composites in which the piezoelectric ceramic is a fibrous-like material. U.S. 4,731,805 discloses an ultrasonic transducer having air in the spaces between the piezoelectric posts with the air spaces between the posts being kept to a minimum resulting in high volume-fill of the piezoelectric material. U.S. 4,728,845 discloses a piezoelectric composite of 1-3-0 connectivity having a void within the polymer matrix which isolates the lateral sides of the piezoelectric rods from pressures transverse to the axes of the rods.. It is generally the objective of the foregoing art to provide piezoelectric materials with easily compressible, low density construction resulting in low acoustic impedance, so that they can be used in the construction of transducers and hydrophones. The attainment of low density and high compliance is one which has not yet been adequately addressed by the developments of the art. Summary of the InventionThe present invention provides a ferroelectric ceramic transducer having low density, high compliance and improved electrical properties. These desirable characteristics are achieved by the preparation of a ferroelectric ceramic transducer with an air-filled kerf. A ferroelectric transducer element, constructed in accordance with the present invention, includes a plurality of ferroelectric ceramic posts spaced apart with no intervening solid or liquid material between the lateral surfaces of the posts. Each of the posts has a first end and a second end and the total volume of the plurality of posts themselves is no greater than sixty percent of the entire volume of the space defined by the plurality of posts. First electrode layer means electrically connect the first ends of the ferroelectric ceramic posts together and second electrode layer means electrically connect the second ends of the ferroelectric ceramic posts together. A polymer front layer is attached to the first electrode layer means and a polymer back layer is attached to the second electrode layer means. Each of the polymer layers has a shear wavelength at the nominal center operating frequency of the transducer element which is at least three times as large as the shortest distance between the lateral surfaces of neighboring ferroelectric ceramic posts. The ferroelectric transducer element just described can function by itself as a transducer or can be one of a number of such transducer elements arranged in an array which makes up a transducer. Brief Description of the DrawingsFigure 1 is a perspective view, partially broken away, of a ferroelectric transducer element constructed in accordance with the present invention. Figure 2 is a horizontal sectional view of the Figure 1 ferroelectric transducer element. Figure 3 is a horizontal sectional view of an array of ferroelectric transducer elements constructed in accordance with the present invention. Detailed Description of the InventionPractically all piezoelectric composite materials used for making thickness mode transducers have a 1-3 connectivity structure with posts which are narrow with respect to their height. These posts are made from a suitable piezoelectric ceramic, such as lead zirconate titanate (PZT), lead titanate or lead metaniobate or a suitable relaxor ferroelectric material, such as PMN/PT, can be used. The same materials can be used in the present invention, although the present invention is not limited by the types of ferroelectric ceramic which are described. The art suggests that these composites perform as superior piezoelectric units because a polymer is bonded to the sides of the ceramic posts. The polymer is considerably less dense and more compliant than the ceramic. When sound waves strike the composite, the polymer is more easily displaced than the ceramic. Since the materials are bonded together, and the spacing is short with respect to the acoustic wavelength, the limitation on the compression of the filler is the ceramic post. Thus, the energy is transmitted into the post where it can be converted to electrical energy and removed as a signal via the electrodes. The art is replete with examples of attempts to modify the composition and structure of the ceramic polymeric matrix in attempts to optimize performance for intended applications. Representative examples of such attempts are those disclosed in U.S. 4,613,784; 4,412,148; 4,683,396; 4,371,805; 4,728,845; 4,628,223; 4,726,099; 4,671,293; 4,640,291; 4,572,981; and 4,518,889. The disclosures of the foregoing patents are incorporated herein by reference. In practice, a transducer is always used in conjunction with additional supporting structures. It, therefore, is feasible to prepare a ferroelectric transducer element without any polymeric filler. In this invention, the filler becomes unnecessary since the forces on the outside layers and electrodes are transmitted directly to the posts. Referring now to Figures 1 and 2, a ferroelectric transducer element 100, constructed in accordance with the present invention, includes a plurality of ferroelectric ceramic posts 102 spaced apart with no intervening solid or liquid material between the lateral surfaces of the posts. The spaces between posts 102 can be filled with air or, if desired, evacuated to form a vacuum. Ferroelectric transducer element 100 also includes first electrode layer means 104a and second electrode layer means 104b. Electrode layer means 104a are electrically connected to the first (i.e. upper) ends of posts 102 to electrically connect the first ends of posts 102 together and electrode layer means 104b are electrically connected to the second (i.e. lower) ends of posts 102 to electrically connect the second ends of posts 102 together. Ferroelectric transducer element 100 further includes a polymer front layer 106a and a polymer back layer 106b. Front layer 106a is attached to electrode layer means 104a and back layer 106b is attached to electrode layer means 104b. By characterizing front layer 106a and back layer 106b as polymer layers, it is intended to include layers which are pure polymers and layers which are polymers filled with ceramic, metal, metal oxide and the like powders or microballoons. The electrode layer means 104a and 104b can be single layers, as shown, or multi-layers at the ends of posts 102. As shown, each electrode layer means includes a single layer to which polymer front layer 106a or polymer back layer 106b is attached. As an alternative, each post 102 can have a second electrode layer at each end disposed between the end of the ceramic material and the electrode layer to which the polymer layer is attached. Usually the sides of the transducer element will be sealed when the element functions as a transducer by itself. Such sealing means can be an O-ring or a polymeric layer 108, shown in Figure 2 but not shown in Figure 1, which extends around the lateral sides of the space defined by the plurality of posts. When the ferroelectric transducer element is but one part of an array of transducer elements positioned side-by-side, such as the four-element array illustrated in Figure 3, the sealing means can be arranged to seal the array as a whole, rather than sealing each individual transducer element within the array. This new construction, just described, is referred to herein as an air kerf composite because the posts are separated from each other only by air. As used herein, the term kerf refers to the space between the ceramic posts. In accordance with the present invention, the total volume of the plurality of posts 102 themselves is no greater than sixty percent of the entire volume of the space defined by the plurality of posts. The preferred volume-fill of ceramic is determined by the specific design requirements. Low volume-fill is desirable for obtaining low acoustic impedance, but, in some cases, high volume-fill might be preferable for obtaining low electrical impedance. In applications where a volume-fill of less than twenty percent results in acceptable electrical impedance, the present invention provides added benefit over 1-3 ceramic polymer composites in that the pressure in the polymer front layer and polymer back layer is entirely applied to the ceramic posts, rather than being distributed over both ceramic posts and intervening polymer material. This improves the operation of the transducer because all of the incident energy enters the posts resulting in improved conversion efficiency. A related characteristic is that the polymer front layer and polymer back layer each have a shear wavelength at the nominal center operating frequency of the transducer element which is at least three times as large as the shortest distance between the lateral surfaces of neighboring posts. Ceramic posts 102 can be in the form of rods, bars, or the like and can have various cross-sections. In one preferred form of the present invention, the length of each post 102 is one-half of the wavelength of the nominal center operating frequency of ferroelectric ceramic transducer element 100. In a second preferred form of the present invention, the length of each post 102 is one-quarter of the wavelength of the nominal center operating frequency of ferroelectric ceramic transducer element 100. Electrode layer means 104a and 104b can be made from any suitable metal, such as gold, silver, nickel, chrome or an alloy of palladium and silver, arranged in single or multiple layers as described previously. Front layer 106a and back layer 106b can be made from any suitable polymer, such as an epoxy, with or without a filler as described previously. When the length of posts 102 is one-half of the wavelength of the nominal center operating frequency of the transducer element, polymer back layer 106b is arranged to have an acoustic impedance which is lower than the acoustic impedance of the transducer element. When the length of posts 102 is one-quarter of the wavelength of the nominal center operating frequency of the transducer element, polymer back layer 106b is arranged to have an acoustic impedance which is higher than the acoustic impedance of the transducer element. In addition, the acoustic impedance of polymer front layer 106a preferably is within the range between the composite acoustic impedance of ferroelectric transducer element 100 and the acoustic impedance of the medium into which transmissions from the transducer element are propagated or from which transmissions are received by the transducer element. One advantage associated with the air kerf composite, just described, is that post-to-post isolation will be a function of the surface waves on the front and rear surfaces, as opposed to waves travelling through the filler material. This will lead to better suppression of lateral modes depending on the selection of the layer materials. The air kerf composite shows an absence of shear resonance, full pressure transfer to the ceramic, zero lateral clamping, and vastly reduced lateral coupling, as opposed to the polymeric ceramic piezoelectrics. | A ferroelectric transducer element comprising: a plurality of ferroelectric ceramic posts (102) spaced apart with no intervening solid or liquid material between the lateral surfaces of said posts, each of said posts having a first end and a second end and the total volume of said plurality of posts themselves being no greater than sixty percent of the entire volume of the space defined by said plurality of posts; first electrode layer means (104a) for electrically connecting said first ends of said posts together; second electrode layer means (104b) for electrically connecting said second ends of said posts together; a polymer front layer (106a) attached to said first electrode layer means and having a shear wavelength at the nominal center operating frequency of said transducer element which is at least three times as large as the shortest distance between the lateral surfaces of neighboring posts; and a polymer back layer (106b) attached to said second electrode layer means and having a shear wavelength at the nominal center operating frequency of said transducer element which is at least three times as large as the shortest distance between the lateral surfaces of neighboring posts. A ferroelectric transducer element according to claim 1 wherein: (a) the acoustic impedance of said polymer back layer (106b) is lower than the composite acoustic impedance of said transducer element, and (b) the length of each of said posts (102) is one-half of the wavelength of the nominal center operating frequency of said transducer element. A ferroelectric transducer element according to claim 1 wherein: (a) the acoustic impedance of said polymer back layer (106b) is higher than the composite acoustic impedance of said transducer element, and (b) the length of each of said posts (102) is one-quarter of the wavelength of the nominal center operating frequency of said transducer element. A ferroelectric transducer element according to claim 2 wherein the acoustic impedance of said polymer front layer (106a) is within the range between the composite acoustic impedance of said transducer element and the acoustic impedance of the medium into which transmissions from said transducer are propagated or from which transmissions are received by said transducer. A ferroelectric transducer element according to claim 3 wherein the acoustic impedance of said polymer front (106a) layer is within the range between the composite acoustic impedance of said transducer element and the acoustic impedance of the medium into which transmissions from said transducer are propagated or from which transmissions are received by said transducer. A ferroelectric transducer element according to claim 1 further including means (108) extending around the lateral sides of said space defined by said plurality of posts (102) for sealing said space defined by said plurality of posts. A ferroelectric transducer element according to claim 4 further including means (108) extending around the lateral sides of said space defined by said plurality of posts (102) for sealing said space defined by said plurality of posts. A ferroelectric transducer element according to claim 5 further including means (108) extending around the lateral sides of said space defined by said plurality of posts (102) for sealing said space defined by said plurality of posts. A ferroelectric transducer element according to claim 6 wherein said posts (102) are formed from a piezoelectric material. A ferroelectric transducer element according to claim 9 wherein said posts (102) are formed from a piezoelectric material selected from the group consisting of lead zirconate titanate, lead titanate and lead metaniobate. A ferroelectric transducer element according to claim 10 wherein said electrode layer means (104a, 104b) are formed from a material selected from the group consisting of gold, silver, nickel, chrome and an alloy of palladium and silver. A ferroelectric transducer element according to claim 6 wherein said posts (102) are formed from a relaxor ferroelectric material. A ferroelectric transducer element according to claim 12 wherein said relaxor ferroelectric material is PMN/PT. A ferroelectric transducer element according to claim 13 wherein said electrode layer means are formed from a material selected from the group consisting of gold, silver, nickel, chrome and an alloy of palladium and silver. A ferroelectric transducer array comprising: a plurality of ferroelectric transducer elements (100) positioned side-by-side to form an array of said elements, each of said ferroelectric transducer elements having: (a) a plurality of ferroelectric ceramic posts (102) spaced apart with no intervening solid or liquid material between the lateral surfaces of said posts, each of said posts having a first end and a second end and the total volume of said plurality of posts themselves being no greater than sixty percent of the entire volume of the space defined by said plurality of posts; (b) first electrode layer means (104a) for electrically connecting said first ends of said posts together; (c) second electrode layer means (104b) for electrically connecting said second ends of said posts together; (d) a polymer front layer (106a) attached to said first electrode layer (104a) means and having a shear wavelength at the nominal center operating frequency of said transducer element which is at least three times as large as the shortest distance between the lateral surfaces of neighboring posts; (e) and a polymer back layer (106b) attached to said second electrode layer (104b) means and having a shear wavelength at the nominal center operating frequency of said transducer element which is at least three times as large as the shortest distance between the lateral surfaces of neighboring posts. A ferroelectric transducer array according to claim 15 wherein said posts (102) are formed from a piezoelectric material. A ferroelectric transducer array according to claim 16 further including means (108) extending around the lateral sides of said array of ferroelectric transducer elements for sealing said array. A ferroelectric transducer array according to claim 15 wherein said posts (102) are formed from a relaxor ferroelectric material. A ferroelectric transducer array according to claim 18 further including means (108) extending around the lateral sides of said array of ferroelectric transducer elements for sealing said array. | INTERSPEC INC; INTERSPEC, INC. | OAKLEY CLYDE G; OAKLEY, CLYDE G. |
EP-0490261-B1 | 490,261 | EP | B1 | EN | 19,960,717 | 1,992 | 20,100,220 | new | H04N1 | null | H04M1, H04N1, H04M11 | T04N201:327C3B, T04N201:327C2B, T04N201:327C3E, T04N201:327C4B, H04N 1/327C, T04N201:327C3F | Facsimile system | A facsimile system includes: a telephone apparatus (3); a facsimile receiving device (9) for detecting a CNG (Calling Tone) signal, which follows a call request signal from a telephone exchange, on a telephone line, and receiving a facsimile data through the telephone line if the CNG signal is detected; a switching device (SW3) for selectively connecting the telephone line to either the facsimile receiving device or the telephone apparatus; a device (10) for controlling the switching device such that the switching device connects the telephone line to the telephone apparatus if the CNG signal is not detected by the facsimile receiving device while the telephone line is connected to the facsimile receiving device; and a device (13) for generating a control signal if the CNG signal is not detected by the facsimile receiving device. The facsimile system also includes a pseudo-call requesting device (1) connected to the generating device and the telephone apparatus for outputting a pseudo-call request signal, which is substantially same as the call request signal from the telephone exchange, to the telephone apparatus to make the telephone apparatus ringing when the control signal is inputted from the generating device. | BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates to a facsimile system in accordance with the precharacterizing part of claim 1. Such a facsimile system is known from US-A-4,910,764. 2. Description of the Related ArtsA facsimile apparatus is developed to be reduced in its size and weight nowadays. Especially, as a facsimile apparatus of low cost and low grade model for the ordinary household use, such a facsimile apparatus as can be externally connected to the conventional telephone apparatus and has only a basic facsimile function, is being well developed. In this kind of facsimile apparatus for the ordinary househld use, the facsimile apparatus shares one telephone line with the telephone apparatus. Accordingly, in one type of such a facsimile apparatus, when the call is requested to the relevant telephone number,the operator firstly hears and checks the sound outputted from the speaker of the handset of the telephone apparatus by himself, and manually starts either the facsimile receiving operation by use of the facsimile apparatus (facsimile receiving mode) or the conversation by use of the telephone apparatus (conversation mode). The inventors of the present invention know a developed type of the facsimile apparatus having a TEL/FAX automatically switching function, in which the facsimile apparatus is adapted such that the conversation mode is firstly set when the call arrives, that is to say, the telephone line is firstly automatically connected to the telephone apparatus through the facsimile apparatus so as to ring the telephone apparatus for the predetermined times. Then, the facsimile receiving mode is subsequently set, that is to say, the telephone line is automatically connected to the facsimile apparatus so that it can start the facsimile receiving operation, if the operator does not respond to this ringing sound by picking up the handset (OFF hook) during the conversation mode. Thus, in this case, if the calling station is a telephone apparatus, the operator can not establish the conversation of the telephone apparatus any more, since the telephone line is not connected to the telephone apparatus in this facsimile receiving mode, which is a problem in the practical use of this type of facsimile system. The inventors of the present invention know another developed type of the facsimile apparatus, which has a re-ringing function to overcome this problem. Namely, this facsimile apparatus judges whether the calling station is a facsimile apparatus or a telephone apparatus by checking the CNG (Calling Tone) signal, which is supposed to be generated and transmitted from the facsimile apparatus. If it is found that the calling station is a telephone apparatus, the facsimile apparatus generates a pseudo-ringing sound by an exclusive pseudo-ringing device provided in the facsimile apparatus so as to ring up the operator at the site of the facsimile apparatus. In this facsimile apparatus provided with the pseudo-ringing function, the sound can be generated only at the site of the facsimile apparatus i.e. not at the site of the telephone apparatus. Thus, if the telephone apparatus is located near the facsimile apparatus, the sound generated by the facsimile apparatus can be heard at the site of the telephone apparatus as well by the operator without any problem. However, if the telephone apparatus is located remote from the facsimile apparatus, the pseudo-ringing sound can not be heard by the operator who is in the vicinity of the telephone apparatus, which is the problem in this type of facsimile apparatus. Since the telephone apparatus is often located to such a remote place especially in case of the cord-less telephone, which is being well developed nowadays, this problem is quite serious in a practical sense. On the other hand, in case of a facsimile apparatus of a high cost and high grade model for the business use, the facsimile may be provided with many sophisticated functions such as a telephone line holding function, and a call requesting function to call the telephone apparatus, which is externally furnished with respect to the facsimile apparatus, just in the same manner as the calling station calls the telephone apparatus via the telephone exchange through the telephone line. Namely this facsimile apparatus can make the telephone apparatus ringing even when the call request signal from the telephone exchange through the telephone line is not inputted to the facsimile apparatus. Thus, this facsimile apparatus is adapted to ring the external telephone apparatus whenever it is necessary in the TEL/FAX automatically switching operation i.e. to make a real ringing sound of the telephone apparatus, in place of the above mentioned pseudo-ringing sound generated by the facsimile apparatus. Accordingly, the operator can hear this real ringing-sound at the site of the telephone apparatus even if it is located remote from the facsimile apparatus, without the above mentioned problem. However, in case of such a sophisticated facsimile apparatus of a high cost and high grade model for the business use, the body of the facsimile apparatus itself becomes very large, and it is also very expensive for the ordinary househoid use. US-A-4,910,764 discloses a facsimile and voice communication device corresponding to the precharacterzing part of claim 1. An interface device allows a telephone and a facsimile to effectively share a common telephone line. When an incoming call is detected, a check is performed to determine if either the facsimile or telephone are in off-hook state. The interface device connects the call and a local ringer generates ringing signals which are sent to the caller. While the ringing is occurring, the interface device senses for a tone characteristic of a facsimile transmission. If a tone is detected, the call is connected to the facsimile with a local ringer activating the facsimile. If a tone is not detected, the call is connected to the phone with the local ringer alerting the called party that an incoming voice call has been received. When the call is completed, the interface unit is reset to receive another telephone call. If the call is never connected, i.e. if the caller hangs up, a dial tone sensor detects for a dial tone on the telephone line. This known facsimile and voice communication device does not specifically address the physical location of both, the telephone apparatus and the communication's interface device in relation to the facsimile apparatus. Earlier European Application EP-A-0 458 540 published on 27 November 1991 and having the priority dates of 21 March 1990 and 4 June 1990 is prior art according to Article 54(3) and (4) EPC in so far as the same contracting states DE, FR and GB are designated. Also this Document does not specifically address the problem of the physical location of the telephone apparatus and the interface circuitry in relation to the facsimile apparatus. SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a facsimile system suitable for the household use, in which the above mentioned problem associated with the ringing operation of the telephone apparatus in the TEL/FAX automatically switching function, can be effectively eliminated at a low cost and in a quite versatile manner, and in which a highly convenient TEL/FAX automatically switching function can be realized. According to the present invention, the above object is achieved by a facsimile system having a TEL/FAX switching function, comprising a telephone apparatus, a facsimile apparatus, having a first terminal and a second terminal, said facsimile apparatus including a facsimile receiving means for detecting a CNG (Calling Tone) signal, which follows a call request signal from a telephone exchange on said first terminal and receiving a facsimile data trough said first terminal if said CNG signal is detected; a switching means for selectively connecting said first terminal to either said facsimile receiving means or said second terminal; means for controlling said switching means so as to connect said first terminal to said facsimile receiving means on ringing said telephone apparatus a predetermined number of times and to connect said first terminal to said second terminal, if said CNG signal is not detected by said facsimile receiving means within a predetermined period after connecting said first terminal to said facsimile receiving means means for generating a Dual Tone Multi Frequency (DTMF) - signal and supplying it to said first terminal , if said CNG signal is not detected by said facsimile receiving means within a predetermined period, and; a pseudo-call requesting apparatus to be connected to a telephone line, to said facsimile apparatus and to said telephone apparatus, for outputting a pseudo-call request signal, which is substantially same as said call request signal from said telephone exchange, to said telephone apparatus to make said telephone apparatus ring when said DTMF signal is inputted from said facsimile apparatus, characterized in that said pseudo-call requesting apparatus has a first terminal connected to said first terminal of said facsimile apparatus in order to connect said telephone line to said facsimile apparatus and receive said DTMF signal from said facsimile apparatus and a second terminal connected to said second terminal of said facsimile apparatus in order to connect said telephone line to said telephone apparatus via said facsimile apparatus, and said facsimile receiving means, said switching means , said control means and said generating means are provided in one unit of a facsimile apparatus and said telephone apparatus, and said pseudo-call requesting apparatus can be placed at a distance away from said facsimile apparatus (claim 1). According to the present invention, when there is a call to the present facsimile system, the telephone line is connected as the original state, by the switching means under the control of the control means, to the telephone apparatus (conversation mode) for the predetermined number of times of the arrived call request signal, so as to make the telephone apparatus ringing during the corresponding period. Then, if the operator does not respond to the telephone apparatus, the telephone line is connected, by the switching means under the control of the control means, to the facsimile receiving means (facsimile receiving mode). Alternatively, the telephone line may be connected as the original state, by the switching device under the control of the control means to the facsimile receiving means. In either case, when the telephone line is connected to the facsimile receiving means, the facsimile receiving means responds to the pertinent call request signal from the telephone exchange. Accordingly, the call request signal is ceased, and the communication on the telephone line between the facsimile system and the calling station is established. Then the facsimile receiving means checks if there is a CNG signal on the telephone line. If the facsimile receiving means detects the CNG signal, and judges that the calling station is the facsimile apparatus for requesting facsimile communication. Thus, the facsimile receiving operation is started by the facsimile receiving device. On the other hand, if the facsimile receiving means does not detect the CNG signal, the facsimile receiving means judges that the calling station is a telephone apparatus for requesting a telephone conversation (i.e. voice communication). Then, the generating means generates and outputs the DTMF (Dual Tone Multi-Frequency) signal, to the pseudo-call requesting apparatus. Then, the pseudo-call requesting apparatus generates and outputs the pseudo-call request signal, which is substantially same a she real call request signal from the telephone exchange. Accordingly, though there does not exist the real call request signal on the telephone line at this time, the telephone apparatus can be made ringing by this pseudo-call request signal, in the pertinent TEL/FAX automatic switching operation, just in the same manner as when the real call request signal is inputted to the telephone apparatus. Thus, even if the telephone apparatus is located remote from the facsimile receiving means, the operator in the vicinity of the telephone apparatus can still hear the real ringing sound of the telephone apparatus in this case and can establish the conversation on the telephone apparatus without any problem. In the present invention, the facsimile receiving device, the switching device, the control device and the generating device are provided in one unit of a facsimile apparatus. In this case, the pseudo-call requesting device is equipped between thus constructed facsimile apparatus and the telephone apparatus. Here, the construction of the facsimile system becomes quite advantageous in that a facsimile apparatus quite similar in its specification to that of the rather simple facsimile apparatus in the aforementioned related art for the household use, can be employed as the facsimile apparatus, while the above mentioned very convenient TEL/FAX automatic switching operation can be realized with such a simple facsimile apparatus and a conventional type telephone apparatus, just by equipping the pseudo-call requesting device between them, with a benefit of making the total cost quite low. Further objects and advantages of the present invention will be apparent from the following description of the preferred embodiment of the invention as illustrated in the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGSFig. 1, which is divided into Fig. 1A and Fig. 1B, is a block diagram of a facsimile system as an embodiment of the present invention; Fig. 2 is a block diagram of the facsimile apparatus and the telephone apparatus, which are directly connected to each other, of the facsimile system of Fig. 1; Fig. 3, which is divided into Fig. 3A, Fig. 3B and Fig. 3C is a flowchart showing an operation of the facsimile apparatus of the facsimile system of Fig. 1; Fig. 4 is a flowchart showing an operation of the pseudo-call requesting apparatus of the facsimile system of Fig. 1; and Fig. 5 is a timing chart of various signals in the pseudo-call requesting apparatus of the facsimile system of Fig. 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTA preferred embodiment of the present invention will be described below with reference to the accompanying drawings. Fig. 1, which is composed of Fig. 1A and Fig. 1B, shows a block diagram of a facsimile system as one embodiment of the present invention. In Fig. 1, the facsimile system includes a pseudo-call requesting apparatus 1, a facsimile apparatus 2 and a telephone apparatus 3. The pseudo-call requesting apparatus 1 is connected to a telephone line L at its terminal A. The pseudo-call requesting apparatus 1 is also connected to the facsimile apparatus 2 and to the telephone apparatus 3. More particularly, a terminal B of the pseudo-call requesting apparatus 1 is connected to a terminal BB of the facsimile apparatus 2, and a terminal C of the pseudo-call requesting apparatus 1 is connected to a terminal CC of the facsimile apparatus 2, while a terminal D of the pseudo-call requesting apparatus 1, is connected to the telephone apparatus 3. The telephone apparatus 3 is externally furnished with respect to the facsimile apparatus 2, has a handset 3a, and is adapted to ring when it is dialed i.e. the call request signal, which is normally transmitted from the telephone exchange through the telephone line L in the normal telephone operation, is inputted thereto. The telephone apparatus 3 shares the telephone line L with the facsimile apparatus 3 under the control of a line control unit 10 of the facsimile apparatus 2. The facsimile apparatus 2 is provided with a switch SW3, a facsimile receiving unit 9 and the line control circuit 10, such that the switch SW3 is adapted to be switched so as to connect the telephone line L via the terminals A, B and BB, to either the facsimile receiving unit 9 or the telephone apparatus 3 further via the terminals CC, C and D. The facsimile apparatus 2 has an automatic TEL/FAX switching function, in which the conversation (i.e. voice communication) mode and the facsimile receiving mode can be automatically switched over to each other. More particularly, when the calling station dials the facsimile apparatus 2, the facsimile apparatus 2 allows the pertinent call request signal from the telephone exchange to pass therethrough to the telephone apparatus 3 via the switch SW3 for a predetermined time period, so as to ring the telephone apparatus 3 for predetermined times, and then the facsimile apparatus 2 switches the switch SW3 to the side of the facsimile receiving unit 9 so as to check if there is the CNG signal on the telephone line L, that is to say, the calling station is a facsimile apparatus or not. The facsimile apparatus 2 may be provided with a mode selection switch of a operation panel on the main body of the facsimile apparatus 2, to select either the above mentioned TEL/FAX automatically switching mode or a manual switching mode, in which the operator can manually select the facsimile receiving operation or the telephone operation after checking the CNG signal sound by the handset 3a. The facsimile apparatus 2 is also provided with a pseudo-ringing circuit 11, a hook detection circuit 12 and a DTMF (Dual Tone Multi-Frequency) signal generating circuit 13. The pseudo-ringing circuit 11 generates a pseudo-ringing sound at the site of the facsimile apparatus 2 in order to ring up again the operator after the operation mode is once automatically switched over to the facsimile receiving mode and yet it is found that the voice communication is actually requested by the telephone apparatus of the calling station by checking the CNG signal. The hook detection circuit 12 is adapted to detect the ON/OFF hook condition of the handset 3a of the telephone apparatus 3 via the terminals D, C and CC. The DTMF signal generating circuit 13 is adapted to generate the DTMF signal to the pseudo-call requesting apparatus 1 via the terminals BB and B, so as to start and stop the operation of the pseudo-call requesting apparatus 1. The facsimile apparatus 2 is adapted to be operative too in such a configuration that the facsimile apparatus 2 is directly connected to the telephone line L and to the telephone apparatus 3 (without the pseudo-call requesting apparatus 1 therebetween), since the facsimile apparatus 2 can establish either the facsimile communication by itself or the voice communication by use of the telephone apparatus 3 over the telephone line L, as shown in Fig. 2. As shown in Fig. 2, in order to establish such a configuration, the terminal BB is adapted to be directly connected with the telephone line L while the terminal CC is adapted to be directly connected to the telephone apparatus 3. However, in such a configuration, the telephone apparatus 3 cannot ring after the operation mode is once automatically switched to the facsimile receiving mode and it is found out that the voice communication is actually requested by the telephone apparatus of the calling station, since the call request signal from the telephone exchange, which would make the telephone apparatus 3 ring, does not exist any more on the telephone line L after the facsimile apparatus 2 responds to this call request signal and checks the CNG signal. Thus, if this happens, the operator at the site of the telephone apparatus 3, cannot be aware of the fact that the telephone call is being requested if the telephone apparatus 3 is located remote from the facsimile apparatus 2. Therefore, in the present embodiment, the pseudo-call requesting apparatus 1 is equipped between the facsimile apparatus 2 and the telephone apparatus 3 as shown in Fig. 1, so that the pseudo-call requesting apparatus 1 can make the telephone apparatus 3 ring again when it is required after the facsimile apparatus 2 checks the CNG signal. Namely, the pseudo-call requesting apparatus 1 is adapted to generate and send the pseudo-call request signal, which is substantially same as the real call request signal utilized on the telephone line L in its normal telephone operation. This pseudo-call request signal is generated in correspondence with a specific control signal i.e. the DTMF signal, which is generated by and outputted from the facsimile apparatus 2, as explained hereinbelow in detail. In Fig. 1, the pseudo-call requesting apparatus 1, is provided with a hook detection circuit 4, a pseudo-call request signal generating circuit 5, a loop current supplying circuit 6, a control circuit 7, a DTMF signal detection circuit 8, a switch SW1, and a switch SW2. The hook detection circuit 4 is adapted to detect the ON/OFF hook condition of the handset 3a i.e. detect the ON/OFF operation of the hook of the telephone apparatus 3 by the operator. The pseudo-call request signal generating circuit 5 is adapted to call the facsimile apparatus 2 and the telephone apparatus 3 by transmitting a pseudo-call request signal, for example 16 Hz signal which is same as the real call request signal on the telephone line L. The loop current supplying circuit 6 is adapted to supply the telephone apparatus 3 with a loop current so as to drive the telephone apparatus 3. The switch SW1 is adapted to connect and disconnect the telephone apparatus 3 with the telephone line L via the terminals D, C, CC, BB, B, and A and is closed in its normal status. The switch SW2 is adapted to connect and disconnect the loop current supplying circuit 6 with the telephone apparatus 3 via the terminal D in correspondence with the open or close condition of the switch SW1. The control circuit 7, which is composed of a microprocessor for example, is adapted to control the pseudo-call request signal generating circuit 5, the loop current supplying circuit 6, and the switches SW1 and SW2. The DTMF signal detection circuit 8 is adapted to detect the DTMF signal which is given from the facsimile apparatus 2 via the terminals BB and B, and the control circuit 7 starts and stops its operation according to the detection of this DTMF signal by the DTMF signal detection circuit 8. The construction and the operation of the facsimile system of the present embodiment shown in Fig. 1, will be explained hereinbelow with referring to flowcharts of Fig. 3, which is composed of Fig. 3A, Fig. 3B and Fig. 3C and shows the operation flow of the facsimile apparatus 2, and Fig. 4, which shows the operation flow of the pseudo-call requesting apparatus 1 of Fig. 1. In Fig. 3, the TEL/FAX automatically switching mode, in which the aforementioned automatic TEL/FAX switching function is enabled, is set in the facsimile apparatus 2 in advance by the operator, by use of the mode selection switch (step S1). When there is an arrival of a call from the calling station through the telephone line L to the facsimile apparatus 2, in which the switch SW3 is normally switched to connect the telephone line L to the telephone apparatus 3 via the terminals C, CC and D (step S2), the telephone apparatus 3 starts ringing in correspondence with the call request signal, which is transmitted from the telephone exchange (not shown in Fig. 1) of the telephone line L (step S3). At this time, if the OFF-hook operation of the telephone apparatus 3 by the operator is detected by the hook detection circuit 12 at the step S4 (Yes), the flow branches to the step S5 and the conversation i.e. the voice communication through the telephone line L is established between the telephone apparatus 3 and the telephone apparatus of the calling station. If the OFF hook of the telephone apparatus 3 is not detected by the hook detection circuit 12 at the step S4 (No), this detecting operation is repeated until the predetermined ringing number of times of the telephone apparatus 3 is counted (step S6 and step S7) or until the call request from the telephone exchange is ceased (step S9). If the call request is ceased before ringing for the predetermined times at the step S9 (Yes), the telephone line L is automatically disconnected by the telephone exchange, and the operation of the facsimile system is also ended. On the other hand, when the Off hook is not detected after ringing for this predetermined times at the step S7 (Yes), the flow branches to the step S8, and the switch SW3 is switched to the side of the facsimile receiving unit 9 according to the control of the line control circuit 10, so that the facsimile receiving unit 9 is connected to the telephone line L via the terminals BB, B and A. In this condition, the facsimile receiving unit 9 assumes the calling station is a facsimile apparatus, and is set in a condition of waiting for the arrival of the CNG (Calling Tone) signal from the calling station, and the facsimile receiving apparatus 9 keeps detecting the CNG signal (step S10) for the predetermined time period (step S11). If the CNG signal is detected within this predetermined time period at the step S10 (Yes), the flow branches to the step S12 and the prescribed facsimile receiving operation is performed by the facsimile receiving unit 9. Then, this facsimile receiving operation is continued until all of the facsimile data is transmitted (step S13). When the facsimile receiving operation is finished at the step S13 (Yes), the telephone line L is disconnected (step S14). If the CNG signal is not detected within the predetermined time period at the steps S10 and S11, the flow branches from the step S11 (Yes) to the step S15, and the DTMF signal is generated by the DTMF signal generating circuit 14 and is transmitted to the pseudo-call requesting apparatus 1 via the terminals B and BB. At this time, the pseudo-ringing circuit 11 generates the pseudo-ringing sound (step S16). The operation of the pseudo-call requesting apparatus 1 on receiving the DTMF signal from the facsimile apparatus 2 (step S15), is explained here with referring to Fig. 4. In Fig. 4, the inputted DTMF signal is detected by the DTMF signal detection circuit 8 (step S17). Then, corresponding to this detection of the DTMF signal, the control circuit 7 judges that the calling station is not a facsimile apparatus but a telephone apparatus. Thus, the control circuit 7 switches the switch SW1 to its open condition and switches the switch SW2 to its closed condition, so as to call the telephone apparatus 3 i.e. connect both of the pseudo-call request signal generating circuit 5 and the loop current supplying circuit 6 to the telephone apparatus 3 via the terminal D. When the switch SW1 is switched to its open condition, the control circuit 7 directs the pseudo-call request signal generating circuit 5 to generate the pseudo-call request signal, for example 16 Hz signal, and calls the telephone apparatus 3 (step S18). At the same time, the control circuit 7 operates the switch SW2 alternatively to its open and closed condition corresponding to the generation and cease of the pseudo-call request signal, so as to keep the line loop between the telephone apparatus 3 and the pseudo-call requesting apparatus 1 by supplying the loop current by use of the loop current supplying circuit 6, while the real call request signal from the telephone line L is ceased. In this way, the telephone apparatus 3 is kept ringing by the pseudo-call requesting apparatus 1 in the pertinent condition (step S18). Then, at the step 19, when the OFF hook of the telephone apparatus 3 by the operator is detected by the hook detection circuit 4 (Yes), the control circuit 7 switches the switch SW1 to its closed condition and switches the switch SW2 to its open condition, so as to connect the telephone apparatus 3 to the telephone line L via the terminals D, C, CC, BB, B and A. Consequently, the conversation i.e. the voice communication between the telephone apparatus 3 and the telephone apparatus of the calling station through the telephone tine L, can be established. On the other hand, as for the facsimile apparatus 2, if the OFF hook of the telephone apparatus 3 is not detected within the predetermined time period by the hook detection circuit 12 while counting the pseudo-ringing number of times, at the steps S16, S21 and S22 in Fig. 3, the facsimile apparatus 2 transmits the DTMF signal, in order to stop the call requesting operation of the pseudo-call requesting apparatus 1, by the DTMF signal generating circuit 13 (step S23), and stops the pseudo-ringing circuit 11 to ring (step S24). At this time, as for the pseudo-call requesting apparatus 1, as long as the call request from the calling station is not ceased (step S26), the call requesting operation by use of the pseudo-call request signal generating circuit 5 with respect to the telephone apparatus 3, is continued, until the DTMF signal from the facsimile apparatus 2 is detected by the DTMF signal detection circuit 8 (step S25). If the DTMF signal is detected at the step S25 (Yes), the flow branches to the step S27, and the pseudo-call requesting apparatus 1 stops the call request operation with respect to the telephone apparatus 3. In this way the telephone apparatus 3 stops ringing (S27), and the operation is ended. Then, as for the facsimile apparatus 2 again, when the pseudo-ringing operation is stopped (step S24), the circuit control unit 10 switches the switch SW3 to connect the telephone line L to the facsimile receiving unit 9 via the terminals A, B and BB. When the telephone line L is thus connected to the facsimile receiving unit 9, the facsimile receiving unit 9 assumes that the calling station is a facsimile apparatus and is set in a condition of waiting for the CNG signal from the calling station. In this manner, the facsimile receiving apparatus 9 keeps detecting the CNG signal (step S28). If the CNG signal is detected (Yes), the prescribed facsimile receiving operation is performed by the facsimile receiving unit 9 (step S12). Then, when the facsimile receiving operation is finished (step S13), the facsimile apparatus 2 disconnects the telephone line L (step S14). On the other hand, if the CNG signal is not detected at the step S28 (No), the facsimile apparatus 2 disconnects the telephone line L (step S29) and the operation is ended. Fig. 5 shows a timing chart of the above described operation of the pseudo-call requesting apparatus 1 from the DTMF signal detection to the OFF hook detection. In Fig. 5, there are shown the timings of the DTMF signal inputted to the DTMF signal detection circuit 8, the open/close operation signal (SW1) outputted from the control circuit 7 to the switch SW1, the pseudo-call request signal outputted from the pseudo-call request signal generating circuit 5, the open/close operation signal (SW2) outputted from the control circuit 7 to the switch SW2, and the hook detection signal outputted from the hook detection circuit 4. As shown in Fig. 5, when the DTMF signal is detected by the DTMF signal detection circuit 8 at the time T1, the switch SW1 is switched to its open condition by the control circuit 7, and at the same time, the transmission of the pseudo-call request signal is started by the pseudo-call request signal generating circuit 5. Then, the switch SW2 is started to be alternatively switched to its open and close condition in synchronization with the pseudo-call request signal, and this switching operation of the switch SW2 and this transmitting operation of the pseudo-call request signal are continued until the hook detection circuit 4 detects the OFF hook condition at the time T2 and thus the conversation is enabled. In this manner, during the time interval from the time T1 to the time T2, even though the real call request signal is not given by the telephone exchange through the telephone line L during this time interval, still the telephone apparatus 3 can be kept ringing. Consequently, the operator can be aware that the telephone call is requested to the telephone apparatus 3, even if the telephone apparatus 3 is located remote from the facsimile apparatus 2. For the connections between the pseudo-call requesting apparatus 1, the facsimile apparatus 2, and the telephone apparatus 3, in the above described embodiment, either of the cord connection or the cord-less connection can be employed. In the above described embodiment, if the operation mode is set to the manual switching mode, the pseudo-call request to the telephone apparatus 3 by the pseudo-call requesting apparatus 1, is not necessary, since the operator manually responds to this call request from the telephone exchange by use of the handset 3a of the telephone apparatus 3. The pseudo-call requesting apparatus 1 is effective in case that the telephone apparatus 3 is connected to the facsimile apparatus 2 by the cord-less connection and is located remote from the facsimile apparatus 2, since the telephone apparatus 3 can ring by virtue of the pseudo-call requesting apparatus 1, so that the operator at the vicinity of the telephone apparatus 3, who cannot hear the pseudo-ringing sound generated by the facsimile apparatus 2, can still hear the ringing sound of the telephone apparatus 3 in this case. As described above in detail, according to the present embodiment, the conventional telephone apparatus 3 and the rather simple facsimile apparatus 2 having a little function i.e. a basic function necessary for the facsimile communication and a simple FAX/TEL automatically switching function (having no function to call the external telephone apparatus), can accomplish a quite convenient FAX/TEL automatically switching function, in cooperation with the pseudo-call requesting apparatus 1 which can be equipped between them in a quite versatile manner. By virtue of thus equipped pseudo-call requesting apparatus 1 between the facsimile apparatus 2 and the telephone apparatus 3, the telephone apparatus 3 can ring again in the TEL/FAX automatically switching receiving operation of the facsimile system, after the conversation mode is switched over to the facsimile receiving mode, and then the facsimile apparatus 2 finds out that the calling station is the telephone apparatus. This is because the telephone apparatus 3 can receive the pseudo-call request signal at this time from the pseudo-call requesting apparatus 1 just in the same manner as receiving the real call request signal from the telephone exchange. Thus, even if the telephone apparatus 3 is located remote from the facsimile apparatus 2, the operator in the vicinity of the telephone apparatus 3 can still hear the ringing sound of the telephone apparatus 3 in this case and can establish the conversation on the telephone apparatus 3 without any problem. Further, the construction of the present embodiment is also quite advantageous in that a facsimile apparatus quite similar in its specification to that of the aforementioned related art facsimile apparatus for the household use, can be employed as the facsimile apparatus 2, while the above mentioned very convenient TEL/FAX automatic switching operation can be realized with such a facsimile apparatus and a conventional type telephone apparatus, just by equipping the pseudo-call requesting apparatus 1 between them, with a benefit of making the total cost quite low. Many widely different embodiments of the present invention may be constricted without departing from the scope of the present invention. It should be understood that the present invention is not limited to the specific embodiments described in this specification, except as defined in the appended claims. | A facsimile system having a TEL/FAX switching function, comprising a telephone apparatus (3), a facsimile apparatus, having a first terminal and a second terminal, said facsimile apparatus including a facsimile receiving means (9) for detecting a CNG (Calling Tone) signal, which follows a call request signal from a telephone exchange on said first terminal and receiving a facsimile data trough said first terminal if said CNG signal is detected; a switching means (SW3) for selectively connecting said first terminal to either said facsimile receiving means or said second terminal; means (10) for controlling said switching means so as to connect said first terminal to said facsimile receiving means on ringing said telephone apparatus a predetermined number of times and to connect said first terminal to said second terminal, if said CNG signal is not detected by said facsimile receiving means within a predetermined period after connecting said first terminal to said facsimile receiving means means (13) for generating a Dual Tone Multi Frequency (DTMF) - signal and supplying it to said first terminal , if said CNG signal is not detected by said facsimile receiving means within a predetermined period, and; a pseudo-call requesting apparatus (1) to be connected to a telephone line, to said facsimile apparatus and to said telephone apparatus, for outputting a pseudo-call request signal, which is substantially same as said call request signal from said telephone exchange, to said telephone apparatus to make said telephone apparatus ring when said DTMF signal is inputted from said facsimile apparatus, characterized in that said pseudo-call requesting apparatus has a first terminal connected to said first terminal of said facsimile apparatus in order to connect said telephone line to said facsimile apparatus and receive said DTMF signal from said facsimile apparatus and a second terminal connected to said second terminal of said facsimile apparatus in order to connect said telephone line to said telephone apparatus via said facsimile apparatus, and said facsimile receiving means (9), said switching means (SW3), said control means (10) and said generating means (13) are provided in one unit of a facsimile apparatus (2) and said telephone apparatus (3), and said pseudo-call requesting apparatus can be placed at a distance away from said facsimile apparatus. The facsimile apparatus as claimed in claim 1, characterized in that said pseudo-call requesting apparatus (1) comprises a pseudo-call signal generating means (5) and a loop current supplying means (6) for driving said telephone apparatus (3) to ring. The facsimile apparatus as claimed in claim 1 or 2, characterized in that said facsimile system further comprises means (12) for detecting ON/OFF hook conditions of said telephone apparatus (3). The facsimile system as claimed in claim 3, characterized in that said control means (10) is adapted to count the number of said call request signal, and control said switching means (SW3) to connect said telephone line to said telephone apparatus (3) while counting said number of said call request signal until a predetermined number, and then to connect said telephone line to said facsimile receiving means (9) so as to detect said CNG signal if the OFF hook condition is not detected by said detecting means (12) during said predetermined number of said call request signal. The facsimile apparatus as claimed in any one of claims 1 to 4, characterized in that said pseudo-call requesting apparatus (1) comprises means (4) for detecting ON/OFF hook condition of said telephone apparatus (3), and is adapted to stop outputting said pseudo-call request signal when an OFF hook condition is detected by said detecting means (4). The facsimile apparatus as claimed in claim 1, characterized in that said facsimile apparatus comprises a pseudo-ringing means (11) for making a pseudo-ringing sound if said CNG signal is not detected by said facsimile receiving means (9) while said telephone line is connected to said facsimile receiving means by said switching means (SW3). The facsimile apparatus as claimed in any one of claims 1 to 6, characterized in that said generating means (13) comprises a DTMF (Dual Tone Multi-Frequency) signal generating circuit, and said pseudo-call requesting apparatus (3) includes a DTMF signal detection circuit (8). | SHARP KK; SHARP KABUSHIKI KAISHA | HAYASHI MOTOHIKO; KOTANI MATAHIRA; HAYASHI, MOTOHIKO; KOTANI, MATAHIRA |
EP-0490265-B1 | 490,265 | EP | B1 | EN | 19,970,312 | 1,992 | 20,100,220 | new | H04N3 | null | H04N3 | H04N 3/233 | Transformer coupled voltage clamp for pincushion correction circuit | A horizontal deflection system (20) comprises a horizontal deflection yoke (Lh) and a resonant retrace circuit (24) coupled to the yoke (Lh) and to a switched energy source (Q2) for generating a horizontal deflection current (Ih) in the yoke (Lh). A diode modulator (12) is coupled to the resonant retrace circuit (24). A control circuit (34) operable in a switched mode supplies a control signal (Is) to the diode modulator (12) for modifying the deflection current (Ih) to correct for side pincushion distortion. A transformer (TR1) has a first winding (W1) coupled to the diode modulator (12) and to the control circuit (34) for recovering energy from the diode modulator (12). The transformer (TR1) has a second winding (W2) for receiving the recovered energy from the first winding (W1). A diode clamp (30) is coupled to the second winding (W2) and to a load (RL) driven by a voltage source at a first voltage level, for transferring the recovered energy between the second winding (W2) and the load (RL). The energy is transferred between the first winding (W1) and the second winding (W2) at a second voltage level across the first winding (W1) determined by the first voltage level and the turns ratio of the transformer (TR1). The second voltage level defines an effective voltage clamping level and is related to the operating range of the diode modulator (12). The second voltage level can be adjusted to levels different from the first voltage level by changing the turns ratio of the transformer (TR1). | This invention relates generally to the field of deflection circuits for television apparatus, and in particular, to voltage clamps for switched mode pincushion correction circuits. Diode modulators can be utilized in horizontal deflection circuits for modifying the horizontal deflection current, for example, to correct for side pincushion distortion. The horizontal deflection current is modulated by a parabolic signal at a vertical rate, as is well known in the art. The pincushion correction circuit can be operated in a switched mode in order to conserve energy, as is also well known. A typical prior art circuit, which is found in the CTC-169 television chassis made by Thomson Consumer Electronics, is shown in FIGURE 1. A diode modulator 12 comprises a network having three parallel legs or paths. One leg is a retrace capacitor Crt. A second leg is a damper diode D3. A third leg includes a modulating inductor Lm and a modulating capacitor Cm coupled in series. One junction of the parallel network is coupled to a resonant retrace circuit 24. Resonant retrace circuit 24 includes a horizontal yoke Lh, an S-shaping capacitor Cs, a linearity inductor Llin, another damping diode D2 and a deflection retrace capacitor Crd. The other junction of the parallel network of the diode modulator may be coupled to ground. A control signal is supplied to the diode modulator at the junction of the modulating capacitor Cm and the modulating inductor Lm by a pincushion switch. The pincushion switch is shown as the output switch of a pincushion correction circuit operating in a switched mode. The output switch is transistor Q1. The emitter of transistor Q1 is grounded. The base of transistor Q1 receives a pulse width modulated signal which reflects a vertical rate parabola, the waveform used to correct side pincushion distortion. Transistor Q1 acts as a switch controlled by the pulse width modulated signal. Power dissipation in transistor Q1 is reduced by restricting operation to saturated or cut off conditions. Varying the modulating current Im causes variation of voltage Vm across capacitor Cm. The B+ voltage supplied to the deflection yoke is constant. The voltage Vm varies with current Im. Therefore, the voltage across the S-shaping capacitor Cs must be equal to the difference between the B+ voltage and voltage Vm. Current Im varies as a vertical rate parabola, and accordingly, voltage Vm also varies mainly at a vertical rate. The average value of the voltage Vm, that is the DC component, is a function of the average duty cycle of the base drive to transistor Q1. The duty cycle of the voltage Vm is a function of the pulse width modulating signal at the base of the transistor switch. The trace voltage, which determines the peak value of the horizontal deflection scanning current, equals the difference between the B+ voltage and the value of the voltage Vm. Accordingly, decreasing the value of the modulator voltage Vm increases the value of the trace voltage and increases the amplitude of the horizontal scanning current. Conversely, increasing the value of the voltage Vm decreases the value of the trace voltage and decreases the amplitude of the horizontal scanning current. In order to correct side pincushion distortion, the amplitude of the horizontal deflection scanning current must be greatest at the center of vertical trace and least at the top and bottom of vertical trace. This is achieved by modulating the pulse width with a vertical rate parabola signal. If inductor L1 is open circuited, the voltage across capacitor Cm will be approximately equal to the inductance Lm divided by the sum of the inductances Lm and Ly, where Ly is the inductance of the yoke circuit, the quotient multiplied by the B+ voltage. The ratio of inductance determines the modulating capability, defining an upper voltage level of a modulating range. This upper voltage determines the minimum horizontal yoke current needed to keep the pincushion circuit linear. Transistor Q1 acts as a pulse width modulated controlled switch. Operating transistor Q1 only in saturation or cut off reduces dissipation in transistor Q1 to a minimum. When transistor Q1 is turned on, energy is transferred from the electric field in capacitor Cm to a magnetic field in inductor L1. This lowers the voltage Vm across capacitor Cm. Current ramps up in inductor L1 when transistor Q1 is on. When transistor Q1 turns off, a reverse emf is developed across inductor L1 to keep the current flowing. With no other path for this current, the reverse emf raises the voltage at the collector of transistor Q1. The clamp diode D1 serves to clamp this rising voltage, as well as to recover this stored energy, further increasing efficiency. Capacitor C1 acts to limit this dv/dt until diode D1 can turn on, lowering the peak voltage on transistor Q1 and helping reduce radio frequency interference. In order for the diode D1 to properly clamp and recover this energy, the load on the supply must be greater than the power delivered by the diode modulator, or the supply voltage will rise. Transient and fault conditions can also increase the voltage Vm to levels greater than the peak modulator voltage developed under normal operating conditions. This increased modulator capacitor voltage is applied to the control circuit, particularly the output switching transistor. The overvoltage stress can damage the transistor and other components in the control circuit. Diode D1 is coupled to a convenient voltage source +Vload. The term convenient has important implications in this context. Firstly, the voltage level of the diode clamp sets the upper limit of the operating range of the diode modulator. The upper limit must be high enough to compensate for the particular cathode ray tube driven by the deflection circuit. Accordingly, the voltage source must be larger in magnitude than the necessary upper limit. Secondly, the output switch is subject to damage from inductive overvoltage conditions which can occur when the transistor turns off. The voltage source must be sufficiently loaded by other circuitry as to be able to dissipate the recovered energy from inductor L1. Thirdly, the voltage source should not be much larger than is necessary. Otherwise, considerable energy can be wasted through dissipation. In FIGURE 1, for example, it is assumed that the necessary voltage level for the operating range of the diode modulator is in the range of 25 volts to 30 volts, and that +Vload is a heavily loaded +32 volt source. The voltage clamp can operate safely under these conditions, and without wasting energy. However, a number of circumstances can render the voltage clamp inefficient, or even inoperable. If the operating range of the diode modulator requires more than +32 volts, the voltage source must be changed. Such a source may not be available, or if available, may not be adequately loaded. If the load on the +32 volt source is small, the transistor may be damaged because the overvoltage condition can drive the voltage source out of regulation, causing damage elsewhere as well. In US-A- 4 594 534 a diode modulator for a horizontal deflection circuit is disclosed. In accordance with an inventive arrangement, the voltage clamp can be adjusted to accommodate the operating range of the diode modulator irrespective of the level of the voltage source coupled to the voltage clamp, even if the voltage level is markedly different from the upper limit value. A deflection system according to this inventive arrangement comprises a circuit for generating a resonating deflection current and a circuit for modulating the deflection current. A control circuit operable in a switched mode supplies a control signal to the diode modulator for modifying the deflection current to correct for side pincushion distortion. A transformer has a first winding coupled to the diode modulator and to the control circuit for recovering energy from the diode modulator. The transformer has a second winding for receiving the recovered energy from the first winding. A diode clamp is coupled to the second winding and to a load driven by a voltage source at a first voltage level, for transferring the recovered energy from the second winding to the load. The energy is transferred between the first winding and the second winding at a second voltage level across the first winding determined by the first voltage level and the turns ratio of the transformer. The second voltage level defines an effective voltage clamping level and is related to the operating range of the diode modulator. The second voltage level can be adjusted to levels different from the first voltage level by changing the turns ratio of the transformer. As an example, a secondary winding of the transformer is coupled between ground and the anode of a clamping diode. The cathode of the clamping diode is coupled to a heavy load driven by a +16 volt source. A primary winding of the transformer is coupled between a diode modulator and the output stage of a pincushion correction circuit. The diode modulator controls the deflection current in a resonant retrace deflection circuit to correct for pincushion distortion. The primary winding is more particularly coupled to the output switch of the pincushion correction circuit, for example the collector electrode of a bipolar transistor or the drain of a MOS-FET transistor, which operates in a switched mode. Accordingly, the clamping diode is inductively coupled to the output transistor through the transformer, instead of being directly connected to the output transistor. The maximum value of voltage Vm may be in the range of 25 to 30 volts. A voltage source, suitably loaded, may be only +16 volts. Heretofore, such a source would not be suitable. However, by choosing an appropriate turns ratio for the transformer, for example 2:1 from the primary winding to the secondary winding, a +32 volt clamp level at the output switch can be stepped down to approximately +16 volts. The +16 volt source can thus accommodate the upper limit of the operating range of the diode modulator. The +16 volt source is now a convenient clamping source. If any overvoltage condition results in enough current through the primary winding to cause the voltage level to exceed approximately +32 volts, a corresponding voltage will be induced in the secondary winding somewhat in excess of approximately +16 volts, which will cause the clamping diode to conduct and transfer energy from the transformer to the +16 volt load. Almost any adequately loaded voltage source, irrespective of its voltage level, can now be a convenient voltage source for a voltage clamp. According to a further inventive arrangement, a transformer coupled voltage clamp is fully compatible with a horizontal deflection system incorporating correction of side pincushion distortion. A horizontal deflection system according to this inventive arrangement comprises a horizontal deflection yoke and a resonant retrace circuit coupled to the yoke and to a switched energy source for generating a horizontal deflection current in the yoke. A diode modulator is coupled to the resonant retrace circuit. A control circuit supplies a control signal to the diode modulator for modifying the deflection current to correct for side pincushion distortion. A diode clamp is coupled to a load driven by a voltage source at a first voltage level. A transformer has a first winding coupled between a reference potential and the diode clamp and a second winding coupled between the diode modulator and the control circuit. A second voltage source at a second voltage level relative to the reference potential is developed in the second winding. The second voltage level defines the effective clamping voltage, that is, the upper limit of the operating range of the diode modulator. The second voltage level can be adjusted to a plurality of levels different from the first voltage level by changing the turns ratio of the transformer. According to yet another inventive arrangement, energy is recovered from a deflection current modulator and utilized for supplying energy to other loads in a television receiver. An energy recovery deflection system according to this inventive arrangement comprises a resonant retrace modulator for modifying a deflection current and a first switch for controlling the modulator. A polarized switch is coupled to a load driven by a voltage source. A transformer has a first winding coupled to the modulator and to the first switch for conducting a first current in the first winding when the first switch is conducting. Energy recovered from the modulator is stored in the first winding when the first switch is conducting. The transformer has a second winding coupled to the polarized switch for conducting a second current to the load through the polarized switch when the first switch becomes nonconducting, for transferring energy from the modulator stored in the first winding to the second winding, and then to the load. The first winding tries to maintain the current therethrough after the first switch becomes nonconducting. The voltage on the winding rises rapidly. Energy is transferred to the second winding, developing a voltage on the second winding. As soon as the polarized switch becomes conductive, as for example a diode becoming forward biased, the current flows into the load and the energy is transferred. FIGURE 1 is a partial circuit schematic of a switched pincushion correction circuit, incorporating a diode modulator, according to the prior art. FIGURE 2 is a circuit schematic of a switched pincushion correction circuit, incorporating a diode modulator and having a transformer coupled voltage clamp according to inventive arrangements taught herein. A horizontal deflection system 20 is shown in schematic form in FIGURE 2. The horizontal deflection system 20 incorporates a transformer coupled voltage clamp 30 for a pincushion correction circuit 34. The voltage clamp 30 is not coupled directly to the pincushion switch transistor Q3. Instead, voltage clamp 30 is coupled to one terminal of a secondary winding W2 of transformer TR1. The other terminal of winding W2 is coupled to a source of a reference potential, for example ground. The primary winding W1 of transformer TR1 is coupled between the diode modulator 12 and transistor Q3. The voltage clamp 30 is coupled to a +16 volt source, which is at a voltage level considerably below the upper limit of the operating range of the diode modulator, which is still assumed to be in the range of +25 volts to +30 volts. The +16 volt source drives a load RL, which is deemed to be adequately loaded for use in a voltage clamping arrangement. Clearly, +16 volts is not high enough for proper operation of the diode modulator to fully correct pincushion distortion, even though it is adequately load by RL. However, by choosing the proper turns ratio of windings W1 and W2, almost any voltage level can be developed in winding W1, by stepping up or stepping down the voltage level of the source coupled to the voltage clamp 30. In this example, a turns ratio of 2:1 from primary winding W1 to secondary winding W2 will develop an effective voltage clamping level on the drain of MOS-FET transistor Q3 which is the sum of approximately +32 volts and voltage Vm. Energy is transferred from capacitor Cm to transformer TR1 when transistor Q3 conducts. When transistor Q3 subsequently turns off, a reverse emf is developed. Absent a conductive path for the current in either of windings W1 and W2, the voltage at the undotted terminal of winding W1 rises. The turns ratio is such that the voltage at the anode of diode D2 will cause diode D2 to conduct and transfer the energy from transformer TR1 to the +16 volt load. The turns ratio will allow diode D2 to conduct before the voltage across transistor Q3 rises sufficiently to break down transistor Q3. Overvoltage conditions may occur frequently, for example after many, if not all of the times transistor Q3 turns off. A voltage signal in excess of the sum of +16 volts and the voltage drop across diode D2 will cause diode D2 to conduct and divert energy from the transformer TR1 to the load RL of the +16 volt source instead of to transistor Q3. Winding W1 may not be as effective a filter as choke inductor L1 in smoothing the level of voltage Vm, depending upon the construction of transformer TR1. In this circuit, the choke is turned on and off completely each cycle. Even so, somewhat more ripple can be well tolerated as a trade off for the enhanced flexibility in choosing a voltage source for the voltage clamp. Considering now the entire deflection circuit 20, a winding W3 of a flyback transformer TR2 and a diode D3 are coupled in series between a source of regulated B+ voltage, for example +128 volts, and the collector of a horizontal output transistor switch Q2. A horizontal oscillator and driver circuit 22 supplies a control signal to the base of transistor Q2. The control signal may be at 2fH, where fH is the standard horizontal scanning frequency in a conventional interlaced NTSC system, that is, approximately 15.7 KHz. The 2fH double scanning rate, approximately 32 KHz, can be used for noninterlaced scanning. Various inductances in a 2fH deflection system are generally smaller than those in a 1fH system. All aspects of the invention are appropriate for use at all scanning frequencies, and in systems other than NTSC. The winding W3 of the flyback transformer TR2 is also coupled to a resonant retrace circuit 24. Resonant retrace circuit 24 includes a deflection retrace capacitor Crd, a damper diode D2, a horizontal deflection yoke Lh, a linearity inductor Llin and an S-shaping capacitor Cs. The horizontal rate switching of transistor Q2 generates a horizontal deflection current Ih in the horizontal deflection yoke and a retrace pulse voltage Vrt at the junction of capacitor Crd and diodes D3 and D4. The horizontal deflection current Ih is approximately 14.3 amps peak to peak. A diode modulator 12 enables the deflection current Ih to be modulated by voltage Vm to provide side pincushion correction of the raster scanned on a cathode ray tube. The diode modulator includes a modulator retrace capacitor Crt, a modulator damper diode D3, a modulator inductor Lm and a modulator capacitor Cm. The modulator voltage Vm developed across capacitor Cm is modulated by a pincushion control circuit 34 to provide the side pincushion correction. A modulating current Im flows through modulating inductor Lm, dependent upon the voltage across capacitor Cm. When the control circuit cuts off, a sink current Is continues to flow through the winding W1. Sink current Is is approximately 2.1 amps peak to peak. Diode D4 will conduct after each conduction of transistor Q3. Energy is thus transferred to the load RL of the +16 volt source through transformer TR1. Control circuit 34 includes an comparator A1 and an output pincushion switch transistor Q3, enabling operation of the pincushion correction circuit in a switched mode, to conserve energy. Transistor Q3 is shown as a MOS-FET device, having its drain electrode coupled to winding W1, its source electrode coupled to ground and its gate electrode coupled to the output of comparator A1. Such switched mode control circuits can be coupled to the diode modulator through an inductor, as shown for example by inductor L1 in FIGURE 1. The inductor can limit current and protect the control circuit from high frequency signals. A choke filter can be substantially a short circuit at lower frequencies. In the circuit shown in FIGURE 2, and according to an inventive arrangement, the control circuit is coupled to the diode modulator by an inductor which is at the same time a winding W1 of a transformer TR1. Comparator A1 has four inputs, three coupled to the noninverting input and one coupled to the inverting input. One input is generated by a switching circuit 32, including transistor Q4, diode D6, capacitor C6 and resistors R12 and R13. Circuit 32 is conductive responsive to an input retrace pulse signal FB. Resistor R14 renders the circuit 32 a current source. The current source signal is AC coupled to the noninverting input of comparator A1 through capacitor C6. A repetitive ramp signal is developed across capacitor C9. A parabola generator, not shown, provides a vertical rate parabola to the junction of resistor R2 and capacitor C7. An adjustable resistive network 26 includes resistors R8, R11 and R5. Network 26 provides amplitude adjustment. An adjustable resistive network 28 includes resistors R7 and R10. Network 28 provides a DC level to control raster width. The horizontal ramp input, the parabola input and the DC level from the width control are combined at the noninverting input of comparator A1. The inverting input of comparator A1 is a reference voltage determined by Zener diode Z1, which is rated at 5.6 volts in the circuit shown. The reference voltage can be other values as well, for example ground. A negative feedback path is provided by resistor R9. When the voltage level at the noninverting input of comparator A1 exceeds the reference voltage at the inverting input, transistor Q3 will be turned on to control the side pincushion modulating voltage Vm. The dynamic operating range of the diode modulator is determined by the difference between the voltage at the drain of transistor Q3 and the Zener reference voltage. The width of the output pulses determines the conduction time of transistor Q3. Conduction of transistor Q3 modulates the sink current Is. Sink current Is in turn controls the DC average value component that, in turn, controls the average value of the voltage Vm across capacitor Cm. Voltage Vm is essentially the same as the average value of the voltage at the drain terminal of transistor Q3. The voltage at the drain terminal of transistor Q3 is a function of the duty cycle of transistor Q3. The duty cycle of transistor Q3 varies at a vertical parabolic rate. As a result of the parabolic modulation, the instant within horizontal retrace when transistor Q3 becomes conductive occurs earlier at the center of vertical trace than at the top and bottom of vertical trace. The average value of the level of voltage Vm is at a minimum at the center of vertical trace and at a maximum at the top and bottom of vertical trace. Consequently, the amplitude of the composite deflection current Ih + Im is at a maximum at the center of vertical trace and at a minimum at the top and bottom of vertical trace, thereby providing side pincushion correction. The voltage clamp circuit 30 employs clamping diode D4. The anode of diode D4 is coupled to one terminal of winding W2 of transformer TR1. The other terminal of winding W2 is coupled to a fixed source of potential, for example ground, as shown. The cathode of clamp diode D4 is coupled to the load RL of the +16 volt source through an inductor L2. Inductor L2 functions as a filter choke, to prevent modulation of the voltage source by horizontal rate or higher signals in the diode modulator, which might couple through transformer TR1 from winding W1 to winding W2, for example retrace pulses or pulses resulting therefrom. The filter choke is substantially a short circuit at lower frequencies. The diode clamp will protect the transistor Q3 from transient overvoltage conditions, provided that the +16 volt source is sufficiently loaded by RL. Capacitor C5 is coupled in parallel with diode D4 for damping ringing. Moreover, energy can be recovered from the winding W1. The energy is transferred to the load RL of the +16 volt source by operation of the diode clamp. In other words, none of the existing advantages of diode clamps is compromised by use of a transformer coupled diode clamp according to all of the aspects of this invention. In accordance with another inventive arrangement, the supply voltage for the transistor Q3, which determines the upper limit of the available pincushion correction current and modulating voltage, can be easily set to a desired value by using different transformers TR1 having different turns ratios. The effective voltage clamping level can be stepped up or stepped down. It must be remembered, of course, that the magnitude of the induced current will step up or down inversely with the turns ratio. In the example shown, the turns ratio is 2:1 from winding W1 to winding W2. This provides an effective clamping voltage for transistor Q3 at the sum of approximately +32 volts and voltage Vm. The inventive arrangements taught herein significantly simplify implementation of switched mode pincushion correction circuits, by making a larger number of voltage sources feasible for voltage clamping. | A horizontal deflection circuit having: a horizontal deflection yoke (Lh); a resonant retrace circuit (24) coupled to said yoke (Lh) and to a switched energy source (22, Q2, TR2) for generating a horizontal deflection current (Ih) in said yoke; a diode modulator (12) coupled to said resonant retrace circuit (24); and a source (34) of control signal for said diode modulator (12) for modifying said deflection current (Ih) to correct for raster distortion, characterized by: a transformer (TR1) having a primary winding (W1) coupled between said diode modulator (12) and said source (34), and a secondary winding (W2); and a diode clamp (30) coupled to a load (RL) energized by a power supply at a nominal voltage level, said secondary winding (W2) coupled between said clamp (30) and said power supply. | THOMSON CONSUMER ELECTRONICS; THOMSON CONSUMER ELECTRONICS, INC. | GRIES ROBERT JOSEPH; LENDARO JEFFERY BASIL; WILBER JAMES ALBERT; GRIES, ROBERT JOSEPH; LENDARO, JEFFERY BASIL; WILBER, JAMES ALBERT |
EP-0490269-B1 | 490,269 | EP | B1 | EN | 19,960,228 | 1,992 | 20,100,220 | new | C08F257 | B32B27 | C08F257, B32B27 | C08F 257/02, B32B 27/06 | Graft copolymer and process for producing the same | There is provided a process for producing a styrenic graft copolymer which comprises coplymerizing a styrenic monomer and a styrenic monomer having a hydrocarbon radical with an unsaturated bond in the presence of a catalyst comprising as primary ingredient (A) a transition metal compound and (B) a contact product of an organoaluminum compound and a condensation agent or (C) a compound which produces an ionic complex by reacting with the above-mentioned transition metal compound and subsequently graft polymerizing an ethylenically unsaturated monomer onto the resultant styrenic copolymer. The above-described styrenic graft copolymer is greatly improved in terms of compatibility, adhesivity, coatability and wettability while preserving heat resistance and chemical resistance thereof, and thus effective as a variety of constructional materials and compatibilizing agents. Furthermore, the composition or multi-layer material comprising the above-mentioned styrenic graft copolymer is widely utilized in a variety of application field including film, sheet, especially stampable sheet, container, packaging material, automobile parts, electrical and electronic parts, etc. | BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates to a graft copolymer and a process for producing the same. More particularly, it pertains to a process for efficiently producing a styrenic graft copolymer having excellent impact resistance and heat resistance and favorable compatibility with other types of resins by graft copolymerizing an ethylenically unsaturated monomer onto a styrenic copolymer, especially onto a styrenic copolymer having a syndiotactic configuration; a novel styrenic graft copolymer; a resin composition containing the graft copolymer; and a multi-layer material containing the graft copolymer layer. 2. Description of the Related ArtsHeretofore, styrenic polymers produced by the radical polymerization method have been molded to various shapes by various molding methods and widely used as domestic electrical appliances, office machines, household goods, packaging containers, toys, furnitures, synthetic papers and other industrial materials. Because of their atactic configuration in stereochemical structure, however, such styrene polymers have suffered the disadvantages of inferior heat resistance and chemical resistance. In order to solve the above-mentioned disadvantages of the styrenic polymers having atactic configuration, the group of the present inventors succeeded in the development of the styrene polymers having a high degree of syndiotactic configuration, and further the styrenic copolymers of a styrene monomer and other comonomer (refer to Japanese Patent Application Laid-Open Nos. 104818/1987, 187708/1987 and 241009/1988). These developed styrenic polymers are excellent in heat resistance, chemical resistance and electrical properties and are expected to find application use in a variety of fields. Nevertheless, the above developed polymers, especially syndiotactic polystyrene still involve such problems as poor compatibility with other types of resins, little adhesion to a metal, etc. and insufficient impact resistance. Meanwhile, the polymerization of an olefinic monomer by a cationic transition metal complex has been reported since many years ago. For example, (1) Natta et. al reported the polymerization of ethylene using the composition of titanocene dichloride and triethylaluminum as the catalyst (J. Polymer Sci., 26, 120 (1964)). Breslow et. al reported the polymerization of ethylene by the use of titanocene dichloride and dimethylaluminum chloride as the catalyst (J. Chem. Soc, 79, 5072 (1957)). Further, Dyachkovskii et. al suggested that the polymerization activity of ethylene by the use of titanocene dichloride and dimethylaluminum chloride as the catalyst is based on monomethyl titanocene cations (J. Polymer Sci., 16, 2333 (1967)). However, the activity of ethylene according to the above-mentioned methods is extremely low. In addition, (2) Jordan et. al reported the synthesis of biscyclopentadienylzirconium methyl(tetrahydrofuran) tetraphenyl borate by the reaction of dimethyl zirconocene with silver tetraphenylborate, isolation of the reaction product and the polymerization of ethylene by the use thereof (J. Am, Chem. Soc, 108, 7410 (1986)), and also the synthesis of biscyclopentadienylzirconium benzyl(tetrahydrofuran) tetraphenylborate by the reaction of benzyl zirconocene with ferrocenium tetraphenylborate and isolation of the reaction product (J. Am. Chem. Soc. 109, 4111 (1987)). It was confirmed that ethylene was slightly polymerized by the aforestated catalyst, but the polymerization activity was extremely low. Moreover, (3) Turner et. al proposed a method for polymerizing α-olefin by the use of the combination of a boron complex containing a specific amine such as triethylammonium tetraphenylborate, triethylammonium tetratolylborate, triethylammonium tetra(pentafluorophenyl) borate and a metallocene as the catalyst (refer to Japanese Patent Application through PCT Laid-Open No. 502036/1989). However, the aforestated catalyst systems (1) through (3) are applicable only to the restricted polymerization, that is, homopolymerization of an α-olefin and copolymerization of α-olefinic comonomers and at the present time, are not actually evolved to the polymerization of a styrenic monomer. Meanwhile, Japanese Patent Application Laid-Open No. 7705/1991 discloses a copolymer of an olefin and syndiotactic polystyrene and a copolymer of an olefin, an unsaturated carboxylic acid ester and syndiotactic polystyrene. The copolymers thus obtained are high in crystallinity when the content of a comonomer is low, but become amorphous as the content of a comonomer increases, thus making it impossible to fully realize the mechanical, thermal and chemical properties of syndiotactic polystyrene of its own. Accordingly, the above-mentioned copolymers suffer the drawback that they can not produce a wide variety of materials which make use of the characteristics of syndiotactic polystyrene by compounding with other thermoplastic resin or filler because of the restriction to the amount of a comonomer to be copolymerized. The use of a third component, that is, a compatibilizing agent for the resin is taken into consideration but is not favorable, since a suitable compatibilizing agent is not found because of the higher molding temperature of syndiotactic polystyrene and further, the addition of such an agent possibly causes the degradation in the performance of the composition obtained. Attempts have been made from the different point of view to contrive the evolution of a wide range of application of syndiotactic polystyrene by forming a laminate of it and one of a variety of materials, particularly resinous materials and metals to make use of the characteristics of each of the materials to be used. As an example, syndiotactic polystyrene may be multi-layered, but the lack of interfacial adhesion between the layers causes interlaminar peeling or delamination, making the laminate practically unusable. Although the above-mentioned copolymer is excellent in terms of interfacial adhesion, they are rendered amorphous with increase in the content of a comonomer, thereby markedly degrading the performance thereof. Consequently, a laminating material with excellent properties can not be produced from such copolymers. WO-A 91/07451 which has been published after the priority date of the present invention discloses graft copolymers comprising wherein R and R' are independently selected from the group consisting of hydrogen, alkyl, and the primary and secondary alkyl halides, a ranges from about 14 to 70,000, b ranges from 0 to about 70,000, c ranges from 0 to about 70,000, d ranges from about 1 to 70,000, X comprises a halogen, and Nu comprises a nucleophilic residue provided by a polymeric nucleophile having a molecular weight of at least about 1,000 and being sufficiently nucleophilic such that said nucleophile is capable of donating electrons to benzyl halides. EP-A-0 448 391 which has been published after the priority date of the present application discloses a process for making uniformly sized polymer particles having a selected final particle size within the range of 1 to 50µm, which comprises certain steps as described therein. Under such circumstances, intensive research and investigation were continued by the present inventors in order to overcome the disadvantage of the aforesaid syndiotactic polystyrene and at the same time, develop a styrenic copolymer excellent not only in compatibility with other types of resins and adhesion with metals but also in impact resistance. In the course of the research, it has been found that a specific styrenic copolymer onto which an ethylenically unsaturated monomer is graft polymerized possesses the characteristics meeting the foregoing object. Further research continued by the present inventors finally led to success in developing a process for producing at a high productivity a styrenic copolymer having surpassing properties at an optional graft ratio and at a high productivity by efficiently proceeding with the graft copolymerization. In addition, it has been discovered that the graft copolymer obtained by the above developed process is effective for a variety of applications. SUMMARY OF THE INVENTIONThe present invention provides a process for producing a styrenic graft copolymer which comprises copolymerizing a styrenic monomer and a styrenic monomer having a hydrocarbon radical with an unsaturated bond in the presence of a catalyst comprising as primary ingredients (A) at least one transition metal compound selected from the group consisting of titanium zirconium, hafnium and vanadium compounds and (B) a contact product of an organoaluminum compound and a condensation agent and subsequently graft polymerizing an ethylenically unsaturated monomer onto the resultant styrenic copolymer. The present invention further provides a process for producing a styrenic graft copolymer by the use of a catalyst comprising as primary ingredients said component (A) and (C) a compound of formula (12) and (13) as explained below which produces an ionic complex by reacting with the above-mentioned transition metal compound instead of the catalyst comprising as primary ingredients said components (A) and (B). The present invention further provides a styrenic graft copolymer having syndiotactic configuration which is produced by graft polymerizing an ethylenically unsaturated monomer onto a copolymer of a styrenic monomer and a styrenic monomer having a hydrocarbon radical with an unsaturated bond. The present invention still further provides a resin composition comprising said styrenic graft copolymer and at least one member selected from a thermoplastic resin, an inorganic filler and an organic filler and also provides a multi-layer material having at least one layer containing said styrenic graft copolymer. BRIEF DESCRIPTION OF THE DRAWINGFigures 1 to 7 are each an electron micrograph (x 1000 magnification) showing the rupture cross-section of the strand obtained in Example 17 or Comparative Examples 1 to 3. Figures 8 to 14 are each an electron micrograph (x 1000 magnification) showing the rupture cross-section of the composition obtained in Example 18 or Comparative Examples 4 to 6. DESCRIPTION OF THE PREFERRED EMBODIMENTSThe process according to the present invention comprises the step of producing a styrenic copolymer by copolymerizing a styrenic monomer and a styrenic monomer having a hydrocarbon radical with an unsaturated bond (Step 1) and the step of graft polymerizing an ethylenically unsaturated monomer onto said styrenic copolymer (Step 2). As the styrenic monomer as used in the aforementioned Step 1, various types are available, but the usually used styrenic monomers I are those represented by the following general formula (1): wherein R¹ is a hydrogen atom, a halogen atom or a substituent having at least one atom selected from carbon, oxygen, nitrogen, sulfur, phosphorus, selenium, silicon and tin, m is an integer from 1 to 3 and when m is 2 or 3, each R¹ may be the same or different. Specific examples of the styrenic monomers I include alkylstyrenes such as styrene, p-methylstyrene, o-methylstyrene, m-methylstyrene, 2,4-dimethylstyrene, 2,5-dimethylstyrene, 3,4-dimethylstyrene, 3,5-dimethylstyrene and p-tert-butylstyrene; halogenated styrenes such as p-chlorostyrene, m-chlorostyrene, o-chlorostyrene, p-bromostyrene, m-bromostyrene, o-bromostyrene, p-fluorostyrene, m-fluorostyrene, o-fluorostyrene and o-methyl-p-fluorostyrene; vinylbiphenyls such as 4-vinylbiphenyl, 3-vinylbiphenyl and 2-vinylbiphenyl; vinylphenylnaphthalenes such as 1-(4-vinylphenyl)naphthalene, 2-(4-vinylphenyl)naphthalene, 1-(3-vinylphenyl)naphthalene, 2-(3-vinylphenyl)naphthalene, 1-(2-vinylphenyl)naphthalene and 2-(2-vinylphenyl)naphthalene; vinylphenylanthracenes such as 1-(4-vinylphenyl)anthracene, 2-(4-vinylphenyl)anthracene, 9-(4-vinylphenyl)anthracene, 1-(3-vinylphenyl)anthracene, 2-(3-vinylphenyl)anthracene, 9-(3-vinylphenyl)anthracene, 1-(2-vinylphenyl)anthracene, 2-(2-vinylphenyl)anthracene and 9-(2-vinylphenyl)anthracene; vinylphenylphenanthrene such as 1-(4-vinylphenyl)phenanthrene, 2-(4-vinylphenyl)phenanthrene, 3-(4-vinylphenyl)phenanthrene, 4-(4-vinylphenyl)phenanthrene, 9-(4-vinylphenyl)phenanthrene, 1-(3-vinylphenyl)phenanthrene, 2-(3-vinylphenyl)phenanthrene, 3-(3-vinylphenyl)phenanthrene, 4-(3-vinylphenyl)phenanthrene, 9-(3-vinylphenyl)phenanthrene, 1-(2-vinylphenyl)phenanthrene, 2-(2-vinylphenyl)phenanthrene, 3-(2-vinylphenyl)phenanthrene, 4-(2-vinylphenyl)phenanthrene and 9-(2-vinylphenyl)phenanthrene; vinylphenylpyrenes such as 1-(4-vinylphenyl)pyrene, 2-(4-vinylphenyl)pyrene, 1-(3-2-(4-vinylphenyl)pyrene, 2-(3-vinylphenyl)pyrene, 1-(2-vinylphenyl)pyrene and 2-(2-vinylphenyl)pyrene; vinylterphenyls such as 4-vinyl-p-terphenyl, 4-vinyl-m-terphenyl, 4-vinyl-o-terphenyl, 3-vinyl-p-terphenyl, 3-vinyl-m-terphenyl, 3-vinyl-o-terphenyl, 2-vinyl-p-terphenyl, 2-vinyl-m-terphenyl and 2-vinyl-o-terphenyl; vinylphenyl-terphenyls such as 4-(4-vinylphenyl)-p-terphenyl; vinylalkylbiphenyls such as 4-vinyl-4'-methylbiphenyl, 4-vinyl-3'-methylbiphenyl, 4-vinyl-2'-methylbiphenyl, 2-methyl-4-vinylbiphenyl and 3-methyl-4-vinylbiphenyl; halogenated vinylbiphenyls such as 4-vinyl-4'-fluorobiphenyl, 4-vinyl-3'-fluorobiphenyl, 4-vinyl-2'-fluorobiphenyl, 4-vinyl-2-fluorobiphenyl, 4-vinyl-3-fluorobiphenyl, 4-vinyl-4'-chlorobiphenyl, 4-vinyl-3'-chlorobiphenyl, 4-vinyl-2'-chlorobiphenyl, 4-vinyl-2-chlorobiphenyl, 4-vinyl-3-chlorobiphenyl, 4-vinyl-4'-bromobiphenyl, 4-vinyl-3'-bromobiphenyl, 4-vinyl-2'-bromobiphenyl, 4-vinyl-2-bromobiphenyl and 4-vinyl-3-bromobiphenyl; trialkylsilylvinylbiphenyls such as 4-vinyl-4'-trimethylsilylbiphenyl; trialkylstannylvinylbiphenyls such as 4-vinyl-4'-trimethylstannylbiphenyl and 4-vinyl-4'-tributylstannylbiphenyl; trialkylsilylmethylvinylbiphenyls such as 4-vinyl-4'-trimethylsilylmethylbiphenyl; trialkylstannylmethylvinylbiphenyls such as 4-vinyl-4'-trimethylstannylmethylbiphenyl and 4-vinyl-4'-tributylstannylmethylbiphenyl; halogen-substituted alkylstyrene such as p-chloroethylstyrene, m-chloroethylstyrene and o-chloroethylstyrene; alkylsilylstyrenes such as p-trimethylsilylstyrene, m-trimethylsilylstyrene, o-trimethylsilylstyrene, p-triethylsilylstyrene, m-triethylsilylstyrene, o-triethylsilylstyrene and p-dimethyl-tert-butylsilylstyrene; phenyl group-containing silylstyrenes such as p-dimethylphenylsilylstyrene, p-methyldiphenylsilylstyrene and p-triphenylsilylstyrene; halogen-containing silylstyrene such as p-dimethylchlorosilylstyrene, p-methyldichlorosilylstyrene, p-trichlorosilylstyrene, p-dimethyl-bromosilylstyrene and p-dimethyliodosilylstyrene; silyl group-containing silylstyrene such as p-(p-trimethylsilyl) dimethylsilylstyrene; and a mixture of at least two thereof. As the styrenic monomer having a hydrocarbon radical with an unsaturated bond also as used in the Step 1, various types are available, but are usually used the styrenic monomers II represented by the following general formula: wherein R² is a hydrocarbon radical with an unsaturated bond, n is an integer of 1 or 2, and R¹ and m are as previously defined. In the above-mentioned formula, R¹ is preferably a hydrocarbon radical having 2 to 10 carbon atoms and an unsaturated bond and exemplified by allyl group, methallyl group, homoallyl group, pentenyl group and decenyl group. Specific examples of the styrenic monomers II include p-divinylbenzene, m-divinylbenzene, trivinylbenzene, a monomer having both styrene monomer skeleton and α-olefin skeleton in the same molecule, p-allylstyrene, m-allylstyrene, methallylstyrene, homoallylstyrene, butenylstyrene, pentenylstyrene, decenylstyrene and a mixture of at least two thereof. In this case, the use of a monomer having an olefinic skeleton suppresses crosslinking reaction even at a relatively high copolymerization ratio of the monomer. Hence, such a monomer is suitable for producing a copolymer having a number of graft initiation points. In the Step I of the process according to the present invention, a styrenic monomer and a styrenic monomer having a hydrocarbon radical with an unsaturated bond, especially the aforestated styrenic monomers I and II are copolymerized by the use of a catalyst comprising as primary ingredients (A) a transition metal compound and (B) a contact product of an organoaluminum compound and a condensation agent. As the transition metal compound (A), various types are available, but preferably used compound is at least one compound selected from those represented by the following general formula (4), (5), (6) or (7). M1R3 aR4 bR5 cR6 4-(a+b+c)M2R7 dR8 eR9 3-(d+e) or wherein R³ to R¹⁴ are each a hydrogen atom, halogen atom, alkyl group having 1 to 20 carbon atoms, alkoxyl group having 1 to 20 carbon atoms, aryl group having 6 to 20 carbon atoms, arylalkyl group having 7 to 20 carbon atoms, aryloxy group having 6 to 20 carbon atoms, acyloxy group having 1 to 20 carbon atoms, acetylacetonyl group, cyclopentadienyl group, substituted cyclopentadienyl group or indenyl group; a, b and c are each an integer from 0 to 4, satisfying the relation 0≦a+b+c≦4; d and e are each an integer from 0 to 3, satisfying the relation 0≦d+e≦3; f is an integer from 0 to 2, satisfying the relation 0≦f≦2; g and h are each an integer from 0 to 3, satisfying the relation 0≦g+h≦3; M¹ and M² are each a titanium atom, zirconium atom, hafnium atom or vanadium atom; and M³ and M⁴ are each a vanadium atom. Among the transition metal compounds as described above, those represented by the general formula (4) in which M¹ is a titanium atom or a zirconium atom are preferably used. Among R³ to R¹⁴ represented by the foregoing formulae, specific examples of halogen atoms include chlorine atom, bromine atom, iodine atom and fluorine atom. Examples of the substituted cyclopentadienyl group include a cyclopentadienyl group replaced with at least one alkyl group having 1 to 6 carbon atoms, which is enumerated by methylcyclopentadienyl group, 1,2-dimethylcyclopentadienyl group and pentamethylcyclopentadienyl group. The symbols R³ to R¹⁴ in the above-mentioned formulae may be each independently a hydrogen atom; alkyl group having 1 to 20 carbon atoms exemplified by methyl group, ethyl group, propyl group, n-butyl group, isobutyl group, amyl group, isoamyl group, octyl group and 2-ethyl-hexyl group; alkoxyl group having 1 to 20 carbon atoms exemplified by methoxy group, ethoxy group, propoxy group, butoxy group, hexyloxy group, octyloxy group and 2-ethylhexyloxy group; aryl group having 6 to 20 carbon atoms exemplified by phenyl group and naphthyl group; arylalkyl group having 7 to 20 carbon atoms exemplified by benzyl group, phenethyl group, 9-anthrylmethyl group; or acyloxy group having 1 to 20 carbon atoms exemplified by acetyloxy group and stearoyloxy group, and may be the same or different from each other provided that the above-mentioned conditions are satisfied. Among the transition metal compounds represented by any of the foregoing general formulae (4) to (7), specific examples of titanium compounds include tetramethoxytitanium, tetraethoxytitanium, tetra-n-butoxytitanium, tetraisopropoxytitanium, cyclopentadienyltrimethyltitanium, titanium tetrachloride, titanium trichloride, dimethoxytitanium dichloride, methoxytitanium trichloride, trimethoxytitanium chloride, cyclopenta-dienyltriethyltitanium, cyclopentadienyltripropyltitanium, cyclopentadienyltributyltitanium, methylcyclopentadienyltrimethyltitanium, methylcyclo-pentadienyltribenzyltitanium, 1,2-dimethylcyclopentadienyltrimethyltitanium, tetramethylcyclopentadienyltrimethyltitanium, pentamethylcyclopentadienyltrimethyltitanium, pentamethylcyclopentadienyltriethyltitanium, pentamethylcyclopentadienyltripropyltitanium, pentamethylcyclopentadienyltributyltitanium, pentamethylcyclopentadienyltriphenyltitanium, pentamethylcyclopentadienyltribenzyltitanium, cyclopentadienylmethyltitanium dichloride, cyclopentadienylethyltitanium dichloride, pentamethylcyclopentadienylmethyltitanium dichloride, cyclopentadienyldimethyltitanium monochloride, cyclopentadienyldiethyltitanium monochloride, cyclopentadienyltitanium trimethoxide, cyclopentadienyltitanium triethoxide, cyclopentadienyltitanium tripropoxide, cyclopentadienyltitanium triphenoxide, pentamethylcyclopentadienyltitanium trimethoxide, pentamethylcyclopentadienyltitanium triethoxide, pentamethylcyclopentadienyltitanium tripropoxide, pentamethylcyclopentadienyltitanium tributoxide, pentamethylcyclopentadienyltitanium triphenoxide, cyclopentadienyltitanium trichloride, pentamethylcyclopentadienyltitanium trichloride, cyclopentadienylmethoxytitanium dichloride, cyclopentadienyldimethoxytitanium chloride, pentamethylcyclopentadienylmethoxytitanium dichloride, cyclopentadienyltribenzyltitanium, cyclopentadienyldimethylmethoxytitanium, methylcyclopentadienyldimethylmethoxytitanium, pentamethylcyclopentadienylmethyldiethoxytitanium, indenyltitanium trichloride, indenyltitanium trimethoxide, indenyltitanium triethoxide, indenyltrimethyltitanium, and indenyltribenzyltitanium. As biscyclopentadienyl-substituted titanium compounds, mention may be made of bis(cyclopentadienyl)dimethyltitanium, bis(cyclopentadienyl)diphenyltitanium, bis(cyclopentadienyl)diethyltitanium, bis(cyclopentadienyl)dibenzyltitanium, bis(methylcyclopentadienyl)dimethyltitanium, bis(pentamethylcyclopentadienyl)dimethyltitanium, bis(methyldicyclopentadienyl)dibenzyltitanium, bis(pentamethylcyclopentadienyl)dibenzyltitanium, bis(pentamethylcyclopentadienyl)chloromethyltitanium, and bis(pentamethylcyclopentadienyl)hydridemethyltitanium. In addition, mention may be made of the titanium compound having a cross-linkage type ligand such as ethylene-bis(indenyl)dimethyltitanium, ethylene-bis(tetrahydroindenyl)dimethyltitanium and dimethylsilylene bis(cyclopentadienyl)dimethyltitanium. The aforestated transition metal compound may be in the form of a complex with a Lewis base. In the composition catalyst system of components (A) and (B) in the case where the styrenic polymer segment is required to have a higher molecular weight, the titanium compound in the form of alkoxide or having a substituted π electron type ligand is preferable, whereas in the case where the styrene polymer segment is required to have a lower molecular weight, the titanium compound having a π electron type ligand or halogen ligand is preferable. Among the transition metal compounds represented by any of the above-mentioned general formulae (4) to (7), specific examples of zirconium compounds include cyclopentadienylzirconium trimethoxide, pentamethylcyclopentadienylzirconium trimethoxide, cyclopentadienyltribenzylzirconium, bisindenylzirconium dichloride, dibenzylzirconium dichloride, tetrabenzylzirconium, tributoxyzirconium chloride, and triisopropoxyzirconium chloride. Likewise, specific examples of hafnium compounds include cyclopentadienylhafnium trimethoxide, pentamethylcyclopentadienylhafnium trimethoxide, cyclopentadienyltribenzylhafnium, pentamethylcyclopentadienyltribenzylhafnium, bisindenylhafnium dichloride, dibenzylhafnium dichloride, tetrabenzylhafnium, tributoxyhafnium chloride, and triisopropoxyhafnium chloride. In the same way, specific examples of vanadium compounds include vanadium trichloride, vanadyl trichloride, vanadium triacetylacetate, vanadium tetrachloride, vanadium tributoxide, vanadyl dichloride, vanadyl bisacetylacetate, and vanadyl triacetylacetonate. On the other hand, the component (B) of the catalyst is a contact product of an organoaluminum compound and a condensation agent. The organoaluminum compounds are usually those represented by the general formula AlR15 3 wherein R¹⁵ is an alkyl group having 1 to 8 carbon atoms, enumerated by trialkylaluminum such as trimethylaluminum, triethylaluminum and triisobutylaluminum. Among them, trimethylaluminum is preferable. As the condensation agent, mention may be made of water as a typical one and of the compounds which cause condensation reaction with the above-mentioned trialkylaluminum, exemplified by copper sulfate pentahydrate, adsorbed water by an inorganic or organic substance. Typical examples of the contact product of an organoaluminum compound and a condensation agent, which product constitutes the component (B) of the catalyst to be used in the present invention include the contact product of an trialkylaluminum represented by the general formula AlR153 and water, which is more specifically a chain alkylaluminoxane represented by the general formula (8) wherein q indicates degree of polymerization ranging from 0 to 50, and R¹⁶ stands for an alkyl group having 1 to 8 carbon atoms, or a cyclic aluminoxane having a repeating unit represented by the general formula (9) wherein R¹⁶ is the same as above, and q indicates the number of repeating units ranging from 2 to 50. In general, the contact product of the alkylaluminum compound such as trialkylaluminum and water contains the foregoing chain alkylaluminoxane and cyclic alkylaluminoxane together with unreacted trialkylaluminum, various mixtures of condensates and further the molecules resulting from association in an intricate manner thereof. Accordingly, the resultant contact product varies widely depending upon the conditions of contact of trialkylaluminum with water as the condensation agent. The reaction of the alkylaluminum compound and a condensation agent is not specifically limited in the above case and may be effected according to the publicly known methods, which are exemplified by (1) a method in which an organoaluminum compound is dissolved in an organic solvent and then brought into contact with water, (2) a method in which an organoaluminum compound is first added to the reaction system at the time of polymerization and thereafter water is added thereto, and (3) a method in which an organoaluminum compound is reacted with the water of crystallization contained in metal salts, or the water adsorbed in inorganic or organic materials. The above-mentioned reaction proceeds even in the absence of a solvent but is preferably carried out in a solvent. Examples of the suitable solvent to be used here include aliphatic hydrocarbons such as hexane, heptane and decane, aromatic hydrocarbons such as benzene, toluene and xylene. The aforementioned water may contain up to about 20% of ammonia, amine such as ethylamine, sulfur compound such as hydrogen sulfide, phosphorus compound such as phosphite. The contact product (e.g, an alkylaluminoxane) of an organoaluminum compound and a condensation agent, which product is used as the component (B) of the catalyst according to the present invention is effectively obtained by a method wherein the solid residue produced after contact reaction in the case of a water-containing compound being used is removed by means of filtration and the filtrate is heat treated under ordinary or reduced pressure at 30 to 200°C, preferably 40 to 150°C for 20 minutes to 8 hours, preferably 30 minutes to 5 hours while distilling away the solvent used. The temperature in the aforementioned heat treatment may be pertinently determined according to the various conditions, but should be usually within the above-described range. The temperature lower than 30°C fails to bring about the prescribed effect, whereas that exceeding 200°C causes thermal decomposition of aluminoxane itself, each resulting in unfavorable consequence. The reaction product is obtained in the form of colorless solid or solution depending upon the heat treatment conditions, and can be used as the catalyst solution by dissolving in or diluting with a hydrocarbon solvent according to the demand. Suitable examples of the contact product of organoaluminum compound and a condensation agent which is used as the component (B) of the catalyst, especially an alkylaluminoxane are those in which the area of the high magnetic field component in the methyl proton signal region due to the aluminum-methyl group (Al-CH₃) bond as observed by the proton nuclear magnetic resonance method is not more than 50% of the total signal area. That is, in a proton nuclear magnetic resonance (¹H-NMR) spectral analysis of the alkylaluminoxane in toluene solvent at room temperature, the methyl proton signal due to Al-CH₃ is observed in the region of 1.0 to -0.5 ppm (tetramethylsilane (TMS) standard). Since the proton signal of TMS (0 ppm) is in the region of the methyl proton signal due to Al-CH₃, the methyl proton signal due to Al-CH₃ is measured with 2.35 ppm methyl proton signal of toluene in TMS standard. The methyl proton signal due to Al-CH₃ is divided into two components: the high magnetic field component in the -0.1 to -0.5 ppm region and the other magnetic field component in the 1.0 to -0.1 ppm region. In alkylaluminoxane preferably used as component (B) of the catalyst in the present invention, the area of the high magnetic field component is not more than 50%, preferably 45 to 5% of the total signal area in the 1.0 to -0.5 ppm region. The catalyst to be used in the process of the present invention comprises the above-mentioned components (A) and (B) as the primary ingredients, and if desired, in addition to the above two components, other catalytic component (D) may be added. The catalyst activity can be markedly improved by the addition of the catalytic component (D), which is an organoaluminum compound represented by the following general formula (10): R17 kAlY3-k wherein R¹⁷ is a hydrocarbon radical such as an alkyl group having 1 to 18, preferably 1 to 12 carbon atoms, alkenyl group, aryl group, aralkyl group or alkoxyl group; Y is a hydrogen atom or halogen atom; and k is an integer satisfying the relation 1≦k≦3. Specific examples of the organoaluminum compound as component (D) include trimethylaluminum, triethylaluminum, triisobutylaluminum, dimethylaluminum chloride, diethylaluminum chloride, monomethylaluminum dichloride, monoethylaluminum dichloride and diethylaluminum ethoxide and the combination of at least two thereof. Furthermore, inasmuch as the stereoregularity of the product is not impaired, the catalyst may be subjected to the addition of an organic compound having at least two hydroxyl groups, aldehyde groups or carboxyl groups, said compound being represented by the general formula (11) W-R18-(P)r-R19-W' wherein R¹⁸ and R¹⁹ are each a hydrocarbon radical having 1 to 20 carbon atoms, substituted aromatic hydrocarbon radical having 7 to 30 carbon atoms or substituted aromatic hydrocarbon radical having 6 to 40 carbon atoms and a substituent containing a hetero atom such as oxygen atom, nitrogen atom or sulfur atom; P is a hydrocarbon radical having 1 to 20 carbon atoms, -O-, -S-, -S-S-, R²⁰ is a hydrogen atom or hydrocarbon radical having 1 to 6 carbon atoms; W and W' are each a hydroxyl group, an aldehyde group or a carboxyl group; and r is zero or an integer of 1 through 5. Specific examples of the organic compound represented by the above-mentioned general formula include 2,2'-dihydroxy-3,3'-di-tert-butyl-5,5'-dimethyldiphenyl sulfide and 2,2'-dihydroxy-3,3'-di-tert-butyl-5,5'-dimethylphenyl ether. In the use of the above-described catalyst comprising the components (A) and (B) as the primary ingredients, the proportion of each component varies from case to case with the type of each component, the type of the styrenic monomer as the starting raw material, especially the type of each of the styrenic monomers I and II and other conditions, and can not be unequivocally determined. As a general rule, however, the molar ratio of the aluminum in the component (B) to the transition metal, for example, titanium in the component (A), that is, aluminum/transition-metal in molar ratio is 1 to 10⁶, preferably 10 to 10⁴. In the copolymerization of a styrenic monomer and a styrenic monomer having a hydrocarbon radical with an unsaturated bond, the compounding ratio of the monomers is not specifically limited, but may be pertinently determined according to various situations, and in general, the number of graft initiation points and graft amount desired in the subsequent graft polymerization step (Step 2). In the case where the number of graft initiation points and graft amount are to be increased, they can be increased by increasing the proportion of the styrenic monomer having a hydrocarbon radical with an unsaturated bond (styrenic monomer II, etc.). In the copolymerization of the styrenic monomer I and the styrenic monomer II, the ratio of styrenic monomer II to the sum of the styrenic monomers I and II should be usually 1 x 10⁻¹⁰ to 50 mol%, desirably 1 x 10⁻⁸ to 20 mol%, more desirably 1 x 10⁻⁶ to 15 mol%. The ratio of the monomer to be used as the starting raw material to the catalyst to be used may be reasonably determined, but is usually 1 to 10⁶ preferably 10² to 10⁴ in terms of the ratio of the styrenic monomers I and II to the aluminum in the contact product as the component (B) of the catalyst, that is, the molar ratio of styrenic monomers I and II/aluminum. With regard to the catalyst to be used in the Step (1) of the process according to the present invention, in addition to the catalyst comprising as the primary ingredients, (A) the transition metal compound as defined in claim 1 and (B) the contact product of an organoaluminum compound and a condensation agent, there is used the catalyst comprising as primary ingredients, (A) the transition metal compound and (C) the compound as defined in claim 2 which produces an ionic complex by reacting with the aforementioned transition metal compound, or the catalyst comprising the foregoing components (A), (C) and (D) as the primary ingredients. The transition metal compound to be used as the component (A) may be pertinently selected from the compounds as described hereinbefore but is desirably the compound represented by any of the above-mentioned general formulae (4), (5), (6) and (7), and is more desirably the titanium compound represented by the general formula (4) wherein R³ to R⁶ are each a cyclopentadienyl group, substituted cyclopentadienyl group, an indenyl group, a substituted indenyl group, hydrogen atom, an alkyl group having 1 to 12 carbon atoms, alkoxyl group having 1 to 12 carbon atoms, aryl group having 6 to 20 carbon atoms, aryloxyl group having 6 to 20 carbon atoms, arylalkyl group having 6 to 20 carbon atoms or a halogen atom, provided that at least one of R³ to R⁶ is a cyclopentadienyl group, substituted cyclopentadienyl group, an indenyl group or a substituted indenyl group. The organoaluminum compound to be used as the component (D) may be reasonably selected from the compounds as described hereinbefore but is preferably the compound represented by the general formula (10). The component (C) is a compound which produces an ionic complex by reacting with the transition metal as component (A), and is a coordination complex compound comprising a cation and an anion in which a plurality of radicals are bonded to an element selected from Groups of VB, VIB, VIIB, VIII, IB, IIB, IIIA, IVA and VA of the Periodic Table. The component (C) is represented by the following formula (12) or (13): ([L1-H]u+ v( [M5X1X2 --- Xs ](s-t)-) i or ([L2]u+)v([M6X1X2 --- Xs](s-t)-)i wherein L² is M⁷, R²¹ R²² M⁸ or R233C; L¹ is a Lewis base; M⁵ and M⁶ are each an element selected from Groups of VB, VIB, VIIB, VIII, IB, IIB, IIIA, IVA and VA of the Periodic Table; M⁷ is a metal selected from Groups IB, IIB and VIII of the Periodic Table; M⁸ is a metal selected from Group VIII of the Periodic Table; X¹ to Xs are each a hydrogen atom, dialkylamino group, alkoxyl group, aryloxyl group, alkyl group having 1 to 20 carbon atoms, aryl group having 6 to 20 carbon atoms, alkylaryl group, arylalkyl group, substituted alkyl group, organometalloid group or halogen atom; R²¹ and R²²are each cyclopentadienyl group, substituted cyclopentadienyl group, indenyl group or fluorenyl group; R²³ is a hydrocarbon radical; t is the valency of each of M⁵ and M⁶ indicating an integer of 1 to 7; s is an integer of 2 to 8; u is the ion valency of each of [L¹-H] and [L²], indicating an integer of 1 to 7; v is an integer of 1 or greater; and i = u x v/(s-t). Specific examples of the Lewis base as expressed by the above L¹ include ethers such as dimethylether, diethyl ether and tetrahydrofuran; thioethers such as tetrahydrothiophene; esters such as ethyl benzoate; nitriles such as acetonitrile and benzonitrile; amines such as trimethylamine, triethylamine, tributylamine, N,N-dimethylaniline, 2, 2'-bipyridine and phenanthroline; phosphines such as triethylphosphine and triphenylphosphine. Examples of unsaturated chain hydrocarbons include ethylene, butadiene, 1-pentene, isoprene, pentadiene, 1-hexene and derivatives thereof and those of unsaturated cyclic hydrocarbons include benzene, toluene, xylene, cycloheptatriene, cyclooctadiene, cyclooctatriene, cyclooctatetraene and derivatives thereof. Specific examples of M⁵ and M⁶ include B, Al, Si, P, As, and Sb; those of M⁷ include Li, Na, Ag and Cu and those of M⁸ include Fe, Co and Ni. Specific examples of X¹ to Xs include dialkylamino group such as dimethylamino and diethylamino; alkoxyl group such as methoxy, ethoxy and n-butoxy; aryloxyl group such as phenoxy, 2,6-dimethylphenoxy and naphthyloxy; alkyl group having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, n-octyl, and 2-ethylhexyl; aryl group, alkylaryl group or arylalkyl group each having 6 to 20 carbon atoms such as phenyl, p-tolyl, benzyl, pentafluorophenyl, 3,5-di(trifluoromethyl)phenyl, 4-tert-butylphenyl, 2,6-dimethylphenyl, 3,5-dimethylphenyl, 2,4-dimethylphenyl and 1,2-dimethylphenyl; halogen such as F, Cl, Br and I; and organometalloid group such as pentamethylantimony group, trimethylsilyl group, trimethylgermyl group, diphenylarsine group, dicyclohexylantimony group and diphenylboron group. Specific examples of substituted cyclopentadienyl group of R₂₁ and R₂₂ include methylcyclopentadienyl group, butylcyclopentadienyl group and pentamethylcyclopentadienyl group. Among the compounds represented by the above-mentioned general formula (12) or (13), specific examples of preferably usable compounds include, as the compounds of the formula (12), triethylammonium tetraphenylborate, tripropylammonium tetraphenylborate, tri-n-butylammonium tetraphenylborate, tri-n-butylammonium tetra(o,p-dimethylphenyl)borate, trimethylammonium tetraphenylborate, tri-n-butylammonium tetra(p-trifluoromethyl)borate, triphenylphosphonium tetraphenylborate, tri(methylphenyl)phosphonium tetraphenylborate, tri(dimethylphenyl)phosphonium tetraphenylborate, isopropylammonium tetra(pentafluorophenyl)borate, dicyclohexylammonium tetraphenylborate, triethylammonium tetra(pentafluorophenyl)borate, tri-n-butylammonium tetra(pentafluorophenyl)borate, triethylammonium hexafluoroarsenate, dimethylanilinium tetra(pentafluorophenyl)borate, di-n-butylanilinium tetra(pentafluorophenyl)borate, methyldiphenylammonium tetra(pentafluorophenyl)borate, p-bromo-N,N'-dimethylanilinium tetra(pentafluorophenyl)borate, etc., and as the compounds of the formula (13), ferrocenium tetraphenylborate, ferrocenium tetra(pentafluorophenyl)borate, decamethylferrocenium tetra(pentafluorophenyl)borate, acetylferrocenium tetra(pentafluorophenyl)borate, formylferrocenium tetra(pentafluorophenyl)borate, cyanoferrocenium tetra(pentafluorophenyl)borate, trityl tetraphenylborate, trityl tetra(pentafluorophenyl)borate, silver hexafluoroarsenate, silver hexafluoroanitomonate and silver tetrafluoroborate. With regard to the catalyst to be used in the process of the present invention, in addition to the catalyst comprising the components (A) and (B) as the primary ingredients and the catalyst comprising the components (A), (B) and (D) as the primary ingredients, there are available the catalyst comprising the components (A) and (C) as primary ingredients and as another embodiment, the catalyst comprising the components (A), (C) and (D) as primary ingredient. The compounding ratio of the component (A) to the component (C) is not specifically limited, but is usually 1 : 0.01 to 1 : 100 preferably 1 : 1 to 1 : 10 each in molar ratio. The components (A) and (C) can be used by previously bringing both the components into contact with each other to form the contact product, separating and washing the resultant contact product or by bringing into contact in the polymerization system. The quantity of the components (D) to be used is usually 0 to 100 mol per one mol of the component (A). It is possible to contrive the improvement in polymerization activity by the employment of the component (D), but an excessive loading of the component (D) fails to achieve the effect corresponding to the loading. Meanwhile, the component (D) may be brought into contact with the component (A) or (C) or the contact product of the components (A) and (C) prior to adding into the polymerization system or during the successive addition of each component into the system. The temperature, period of time and method each of polymerization in the aforestated Step (1) may be pertinently determined, but the polymerization temperature is generally 0 to 120°C, preferably 10 to 80°C and the polymerization time is usually 1 second to 10 hours. As the polymerization method, any of bulk, solution and suspension polymerization is available. The usable solvents in solution polymerization are enumerated by aliphatic hydrocarbons such as pentane, hexane and heptane, alicyclic hydrocarbon solvent such as cyclohexane and aromatic hydrocarbons such as benzene, toluene and xylene, among which are preferable the aliphatic hydrocarbons and aromatic hydrocarbons. In the above case, the ratio by volume of the monomer to the solvent (monomer/solvent) may be optionally selected. It is desirable to set the loading of the component (C) so that the molar ratio of the monomer as starting material to the coordination complex compound becomes 1 to 10⁹, more desirably 100 to 10⁷. In the process of the present invention, the production of the styrenic copolymer in Step 1 is followed by the graft polymerization of the ethylenically unsaturated monomer onto the copolymer in Step 2. The chemical structure of the styrenic copolymer as obtained in the Step 1 is not specifically limited. As described hereinbefore, however, in the case where the monomer having a styrene monomer skeleton and an α-olefin skeleton in the same molecule is used as the styrenic monomer having a hydrocarbon radical with an unsaturated bond and polymerized to produce the copolymer by the use of the catalyst according to the process of the present invention, a straight-chain copolymer is efficiently obtained while crosslinking reaction is suppressed even at a relatively high copolymerization ratio of the monomer. As the result of investigation on the cause of the above fact, it has been elucidated that the copolymerization is caused in the α-olefinic skeleton instead of styrenic skeleton, thereby allowing the double bond of styrene to remain unsatured. The copolymer having such a chemical structure has never been known so far. The usable ethylenically unsaturated monomers are those represented by the following general formula: wherein Q¹, Q², Q³ and Q⁴ are each a hydrogen atom, a halogen atom or a substituent having at least one atom selected from carbon atom, oxygen atom, nitrogen atom, sulfur atom, phosphorus atom, selenium atom, silicon atom and tin atom, and may be the same or different. There are available various types of monomers copolymerizable with the repeating unit of the aforestated styrenic copolymer insofar as they are represented by the foregoing formula. Suitable examples of the above monomer include (1) acrylic acid, methacrylic acid and derivatives thereof, (2) acrylamide, methacrylamide and derivatives thereof, (3) vinyl acetate and derivatives thereof, (4) cinnamic acid, crotonic acid and derivatives thereof, (5) acrylonitrile, methacrylonitrile and derivatives thereof, (6) maleic acid, fumaric acid, maleic anhydride and derivatives thereof, (7) maleimide and derivative thereof, (8) itaconic acid, itaconic anhydride and derivatives thereof, (9) acroleins, (10) vinyl ketones, (11) diolefins, (12) styrene and derivatives thereof, (13) α-olefins and (14) cyclic olefins. Examples of the (meth)acrylic acid derivatives in the compound (1) include allyl acrylate; isopropyl acrylate; ethyl acrylate; 2,3-epoxypropyl acrylate; 2-chloroethyl acrylate; acrylic acid chloride; cyclododecyl acrylate; dibromopropyl acrylate; 6,8-dimethyl-1-oxy-5-chromanylmethyl acrylate; 1,2,2,2-tetrachloroethyl acrylate; tetrahydrofurfuryl acrylate; hydroxyethyl acrylate; hydroxypropyl acrylate; η⁶-(acrylic acid 2-phenylethyl)tricarbonyl chromium; butylacrylate; 2-propynyl acrylate; benzyl acrylate; 2-(1-aziridinyl)ethyl methacrylate; p-acetylphenyl methacrylate; 2-acetoxylethyl methacrylate; 1-(9-anthryl)ethyl methacrylate; ethyl methacrylate; 2,3-epithiopropyl methacrylate; 2,3-epoxypropyl methacrylate; octadecyl methacrylate; octafluoropentyl methacrylate; p-chlorophenyl methacrylate; chloromethyl methacrylate; 2-(diethylamino)ethyl methacrylate; cyclohexyl methacrylate; 2,6-di-tert-butylphenyl methacrylate; p-dimethylaminobenzyl methacrylate; 2-(N,N-dimethylcarbamoyloxyethyl)methacrylate; 2,6-dimethylphenyl methacrylate; 1,2,2,2-tetrachloroethyl methacrylate; trifluoroethyl methacrylate; 2,2,4-trimethyl-3-on-1-pentyl methacrylate; p-nitrophenol methacrylate; 2-pyridyl methacrylate; phenyl methacrylate; ferroceneethyl methacrylate; tert-butyl methacrylate; methacrylic acid fluoride; benzyl methacrylate; p-methylphenyl methacrylate; 3,4-methylenedioxybenzyl methacrylate; 2-mercaptobenzothiazole methacrylate and (-)-3-menthyl methacrylate. Examples of the (meth)acrylamide derivatives of the compound (2) include N-methylacrylamide; N-ethylacrylamide; N-isopropylacrylamide; N-n-butylacrylamide; N-sec-butylacrylamide; N-isobutylacrylamide; N-tert-butylacrylamide; N-(1,1-dimethylpropyl)acrylamide; N-cyclohexylacrylamide; N-(1,1-dimethylbutyl)acrylamide; N-(1-ethyl-1-methylpropyl)acrylamide; N-(1,1,2-trimethylpropyl)acrylamide; N-n-heptylacrylamide; N-(1,1-dimethylpentyl)acrylamide; N-(1-ethyl-1-methylbutyl)acrylamide; N-(1-ethyl-1,2-dimethylpropyl)acrylamide; N-(1,1-diethylpropyl)acrylamide; N-n-octylacrylamide; N-(1,1,3,3-tetramethylbutyl)acrylamide; N-(1,2,3,3-tetramethylbutyl)acrylamide; N-(1-ethyl-1-methylpentyl)acrylamide; N-(1-propyl-1,3-dimethylbutyl)acrylamide; N-(1,1-diethylpentyl)acrylamide; N-(1-butyl-1,3-dimethylbutyl)acrylamide; N-dodecylacrylamide; N-(1-methylundecyl)acrylamide; N-(1,1-dibutylpentyl)acrylamide; N-(1-methyltridecyl)acrylamide; N-(1-methylpentadecyl)acrylamide; N-(1-methylheptadecyl)acrylamide; N-(1-adamantyl)acrylamide; N-(7,7-dimethylbicyclo [3,2,0] hepto-6-yl)acrylamide; N-allylacrylamide; N-(1,1-dimethylpropynyl)acrylamide; N-benzylacrylamide; N-phenylacrylamide; N-(2-methylphenyl)acrylamide; N-(4-methylphenyl)acrylamide; N-(1-naphthyl)acrylamide; N-(2-naphthyl)acrylamide; N-methylmethacrylamide; N-ethylmethacrylamide; N-n-butylmethacrylamide; N-tert-butylmethacrylamide; N-n-octylmethacrylamide; N-n-dodecylmethacrylamide; N-cyclohexylmethacrylamide; N-(7,7-dimethylbicyclo [3,2,0] hepto-6-yl)methacrylamide; N-allylmethacrylamide; N-(1,1-dimethylpropenyl)methacrylamide; N-benzylmethacrylamide; N-[1-(4-chlorophenyl)] ethylmethacrylamide; N-phenylmethacrylamide; N-(2-methylphenyl)methacrylamide; N-(3-methylphenyl)methacrylamide; N-(4-methylphenyl)methacrylamide; N,N-bis(2-cyanoethyl)acrylamide; N-(4-cyano-2,2,6,6-tetramethyl-4-piperidyl)acrylamide; N-(2-cyanoethyl) methacrylamide; N-(1,1-dimethyl-2-cyanoethyl)acrylamide; N-(hydroxymethyl)acrylamide; N-(methoxymethyl)acrylamide; N-(ethoxymethyl)acrylamide; N-(n-propoxymethyl)acrylamide; N-(isopropoxymethyl)acrylamide; N-(n-butoxymethyl)acrylamide; N,N'-methylenebisacrylamide; 1,2-bisacrylamideethane; 1,3-bisacrylamidepropan; 1,4-bisacrylamidebutane; 1,5-bisacrylamidepentane; 1,6-bisacrylamidehexane; 1,7-bisacrylamideheptane; 1,8-bisacrylamideoctane; 1,9-bisacrylamidenonane; 1,10-bisacrylamidedecane; 1,12-bisacrylamidedodecane; 1,1,1-trimethylamidne-2-(N-phenyl-N-acryloyl)propaneimide; 1,1-dimethyl-l-(2-hydroxy)propylamine-N-phenyl-N-methacryloylglycineimide; N-(2-dimethylaminoethyl)acrylamide; N-(2-diethylaminoethyl)acrylamide; N-(2-morpholinoethyl)acrylamide; N-(3-dimethylaminopropyl)acrylamide; N-(3-diethylaminopropyl) acrylamide; N-(3-propylaminopropyl)acrylamide; N-[3-bis(2-hydroxyethyl)aminopropyl]acrylamide; N-(1,1-dimethyl-2-dimethylaminoethyl)acrylamide; N-(2,2-dimethyl-3-dimethylaminopropyl)acrylamide; N-(2,2-dimethyl-3-diethylaminopropyl)acrylamide; N-(2,2-dimethyl-3-dibutylaminopropyl)acrylamide; N-(1,1-dimethyl-3-dimethylaminopropyl)acrylamide; N-acryloylglycineamide; N-(2,4-dinitrophenylhydrazone)methyleneacrylamide; 2-acrylamidepropane sulfonic acid; 2-acrylamide-n-butane sulfonic acid; 2-acrylamide-n-hexane sulfonic acid; 2-acrylamide-n-butane sulfonic acid; 2-acrylamide-n-hexane sulfonic acid; 2-acrylamide-n-octane sulfonic acid; 2-acrylamide-n-dodecane sulfonic acid; 2-acrylamide-n-tetradecane sulfonic acid; 2-acrylamide-2-methylpropane sulfonic acid; 2-acrylamide-2-phenylpropane sulfonic acid; 2-acrylamide-2,4,4-trimethylpentane sulfonic acid; 2-acrylamide-2-methylphenylethane sulfonic acid; 2-acrylamide-2-(4-chlorophenyl)propane sulfonic acid; 2-acrylamide-2-carboxymethylpropane sulfonic acid; 2-acrylamide-2-(2-pyridyl)propane sulfonic acid; 2-acrylamide-1-methylpropane sulfonic acid; 3-acrylamide-3-methylbutane sulfonic acid; 2-methacrylamide-n-decane sulfonic acid; 2-methacrylamide-n-tetradecane sulfonic acid; 4-methacrylamidebenzene sulfonic acid sodium salt; N-(2,3-dimethylphenyl)methacrylamide; N-(2-phenylphenyl) methacrylamide; N-(2-hydroxyphenyl)methacrylamide; N-(2-methoxyphenyl)methacrylamide; N-(4-methoxyphenyl)methacrylamide; N-(3-ethoxyphenyl)methacrylamide; N-(4-ethoxyphenyl)methacrylamide; N-(2-chlorophenyl)methacrylamide; N-(3-chlorophenyl)methacrylamide; N-(4-chlorophenyl)methacrylamide; N-(4-bromophenyl)methacrylamide; N-(2,5-dichlorophenyl)methacrylamide; N-(2,3,5-trichlororphenyl)methacrylamide; N-(4-nitrophenyl)methacrylamide; N,N-dimethylacrylamide; N,N-diethylacrylamide; N,N-dibutylacrylamide; N,N-diisobutylacrylamide; N,N-dicyclohexylacrylamide; N,N-bis(4-methylpentyl)acrylamide; N,N-diphenylacrylamide; N,N-bis(5-methylhexyl)acrylamide; N,N-dibenzylacrylamide; N,N-bis(2-ethylhexyl)acrylamide; N-methyl-N-phenylacrylamide; N-acryloylpyrrolidine; N-acryloylpiperidine; N-acryloylmorpholine; N-acryloylthiamorpholine; N,N-dimethylmethacrylamide; N,N-diethylmethacrylamide; N,N-diphenylmethacrylamide; N-methyl-N-phenylmethacrylamide; N-methacryloylpiperidine; N-(2-hydroxyethyl)acrylamide; N-(2-hydroxypropyl)acrylamide; N-(1,1-dimethyl-2-hydroxyethyl)acrylamide; N-(1-ethyl-2-hydroxyethyl)acrylamide; N-(1,1-dimethyl-3-hydroxybutyl)acrylamide; N-(2-chloroethyl)acrylamide; N-(1-methyl-2-chloroethyl)acrylamide; N-(2,2,2-trichloro-1-hydroxyethyl)acrylamide; N-(2,2,2-trichloro-1-methoxyethyl)acrylamide; N-(1,2,2,2-tetrachloroethyl)acrylamide; N-(2,2,3-trichloro-2-hydroxypropyl)acrylamide; N-(2-chlorocyclohexyl)acrylamide; N-(2,2-difluoroethyl)acrylamide; N-(2-2,2-trifluoroethyl)acrylamide; N-(3,3,3-trifluoropropyl)acrylamide; N-(3,3-difluorobutyl)acrylamide; N,N-bis(2,2-difluoroethyl)acrylamide; N,N-bis(2,2,2-trifluoroethyl)acrylamide; ethyl-2-acrylamideacetate; acryloyldicyandiamide; methacryloyldicyandiamide; N-(1-naphthyl)methacrylamide; N-(2-naphthyl)methacrylamide; N-formylacrylamide; N-acetylacrylamide; N-(2-oxopropyl)acrylamide; N-(1-methyl-2-oxopropyl)acrylamide; N-(1-isobutyl-2-oxopropyl)acrylamide; N-(1-benzyl-2-oxopropyl)acrylamide and N-(1,1-dimethyl-3-oxobutyl)acrylamide. Examples of the vinyl acetate and derivatives thereof of the compounds (3) include vinyl acetate, vinyl thioacetate, and vinyl α-(1-cyclohexenyl)acetate. Examples of the derivatives of cinnamic acid and crotonic acid in the compound (4) include ethyl cinnamate, phenyl cinnamate, tert-butylcinnamate, crotonaldehyde, methyl crotonate, ethyl α-cyanocrotonate and methyl α-methoxycrotonate. Examples of the (meth)acrylonitrile derivatives in the compounds (5) include vinylidene cyanide, α-methoxyacrylonitrile, α-phenylacrylonitrile and α-acetoxyacrylonitrile. Examples of the derivatives of maleic acid, fumaric acid and maleic anhydride in the compounds (6) include esters of maleic acid and fumaric acid, substituted maleic acid, fumaric acid and maleic anhydride, which derivatives being specifically exemplified by diethylfumarate, diphenylfumarate, fumaronitrile, methylfurmaric acid, diethylmethyl fumarate, methylmaleic anhydride, dimethylmaleic anhydride, phenylmaleic anhydride, diphenylmaleic anhydride, chloromaleic anhydride, dichloromaleic anhydride, fluoromaleic anhydride, difluoromaleic anhydride, bromomaleic anhydride, dibromomaleic anhydride, methylmaleic acid, dimethylmaleic acid, phenylmaleic acid, chloromaleic acid, dichloromaleic acid, fluoromaleic acid, difluoromaleic acid, bromomaleic acid, dimethylmaleate, diethylmaleate, diethylmethyl maleate, dipropyl maleate, diisopropyl maleate, dibutyl maleate, diisobutyl maleate, dipentyl maleate, diisopentyl maleate, dihexyl maleate, diheptyl maleate, dioctyl maleate, bis(2-ethylhexyl)maleate, dinonyl maleate, dihexadecyl maleate, dipropargyl maleate, bis[2-(2-chloroethoxy)ethyl] maleate, dibenzyl maleate, methylallyl maleate, methyl-2-butenyl maleate, methyl-3-butenyl maleate, allyl-3-methylthiopropyl maleate, allyl-3-ethylthiopropyl maleate, allyl-3-acetylthiopropyl maleate, allyl-3-phenylthiopropyl maleate, methyl-p-chlorophenyl maleate, butyl-p-chlorophenyl maleate, benzyl-p-chlorophenyl maleate, diphenyl maleate, di-m-cresyl maleate, di-p-cresyl maleate, n-heptyl maleate, nonyl maleate, decyl maleate, dodecyl maleate, octadecyl maleate, and fluoroalkyl maleate. Examples of the maleimide derivatives in the compound (7) include n-butylmaleimide, N-phenylmaleimide, N-(2-methylphenyl)maleimide, N-cyclohexylmaleimide, N-(2,6-dimethyl)maleimide, N-(2,6-diethyl)maleimide, and N-(α-naphthyl)maleimide. Examples of the derivatives of itaconic acid and itaconic anhydride in the compounds (8) include diethyl itaconate, di-n-octyl itaconate, cis-glutaconic acid, diethyl cis-glutaconate, trans-glutaconic acid and diethyl trans-glutaconate. Examples of acroleins in the compounds (9) include acrolein, methacrolein, α-chloroacrolein and β-cyanoacrolein. Examples of vinyl ketones in the compounds (10) include methyl vinyl ketone, phenyl vinyl ketone, ethyl vinyl ketone, n-propyl vinyl ketone, cyclohexyl vinyl ketone and isobutyl vinylketone. Examples of diolefins (dienes) of the compounds (11) include 1,3-butadiene, isoprene, 1-ethoxy-1,3-butadiene, chloroprene, 1-methoxy-1,3-cyclohexadiene, 1-acetoxy-1,3-butadiene, 2-acetoxy-3-methyl-1,3-butadiene, 1-chloro-1,3-butadiene, 1-(4-pyridyl)-1,3-butadiene, muconic acid and diethyl muconate. As styrene and derivatives thereof of the compounds (12), there may be used the styrenic monomers I represented by the foregoing general formula (1). In addition to the above, there may be used styrene derivatives each having a hetero atom such as oxygen atom or nitrogen atom including p-dimethylaminostyrene, butyl styrene-sulfonate, p-nitrostyrene, p-hydroxystyrene, 2,3-epoxypropyl, p-vinylbenzoate, p-vinylbenzoyl chloride, phenyl p-vinylbenzoate, methyl p-vinylbenzoate, 3-methoxyphenyl p-vinylbenzoate, p-isopropenylphenol, p-cyanostyrene and p-acetoxystyrene, or α-methylstyrenes. Examples of α-olefins of the compounds (13) include ethylene, propylene, 1-butene, 1-octene and 4-methylpentene-1,3-methylbutene-1. Examples of cyclic olefins of the compounds (14) include monocyclic olefins such as cyclobutene, cyclopentene and cyclohexene; substituted monocylic olefins such as 3-methylcyclopentene and 3-methylcyclohexene; polycyclic olefins such as norbornene, 1,2-dihydroxy-dicyclopentadiene and 1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octahydronaphthalene; and substituted polycyclic olefins such as 5-methylnorbornene, 5-ethylnorbornene, 5-propylnorbornene, 5,6-dimethylnorbornene 1-methylnorbornene, 7-methylnorbornene, 5,5,6-trimethylnorbornene, 5-phenylnorbornene, 5-benzylnorobornene, 5-ethylidenenorbornene, 5-vinylnorbornene, 2-methyl-1,4,5,8-dimethano-1,2,3,4,4a,5,8,8a-octohydronaphthalene, 2-ethyl-1,4,5,8-dimethano-1,2,3,4,h4a,5,8,8a-octahydronaphthalene, 2,3-dimethyl-1,4,5,8-dimethano-1,2,3,4,4a, 5,8,8a-octahydronaphthalene, 5-chloronorbornene, 5,5-dichloronorbornene, 5-fluoronorbornene, 5,5,6-trifluoro-6-trifluoromethylnorbornene, 5-chloromethylnorbornene, 5-methoxy-norbornene and 5-dimethylaminonorbornene. The above-mentioned monomers are properly selected according to the purpose of use of the graft copolymers to be obtained. For example, for the purpose of improving adhesion, preferable monomers are those each having a polar group such as unsaturated carboxylic acid or derivatives thereof. In order to improve heat resistance in addition to the above, preferable monomers are those maleimide or derivatives thereof, cyclic olefins such as norbornene including ethylenically unsaturated monomers causing a high glass transition temperature of the polymer to be obtained. In carrying out the graft polymerization of Step 2 according to the process of the present invention, the foregoing ethylenically unsaturated monomer is added to the styrenic copolymer obtained in Step 1 to effect the polymerization reaction after the unreacted styrenic monomers I and II and the catalyst in Step I are removed as necessary. As the graft polymerization is usually advanced by a polymerization initiator or light irradiation, the ethylenically unsaturated monomer may be added to the styrenic copolymer prior to, during or after the addition of a polymerization initiator to the copolymer or irradiation of the copolymer with light to activate the reaction system and proceed with graft copolymerization. There are available various types of polymerization initiators which have heretofore been used, including anionic polymerization initiators, cationic polymerization initiators and radical polymerization initiators. In addition, the polymerization can be initiated by heat, light (UV ray, visible ray, infrared ray), electron ray or radiation. In the case of grafting α-olefin such as ethylene or propylene, styrenes or cyclic olefins, the use of the catalyst comprising a transition metal and an organometal as the main components can enhance the graft ratio as well as grafting amount. The aforementioned anionic polymerization initiators are exemplified by alkali metal (Cs, Rb, K, Na, Li), alkylated alkali metal (n-butyl-Li, octyl-K, dibenzyl-Ba), aromatic complex of alkali metal (Na-naphthalene) and amidated alkali metal (KNH₂, LiN(C₂H₅)₂). The above-mentioned cationic polymerization initiators are exemplified by Bronsted acid, carbenium ion salt, and halogen. Examples of the Bronsted acid include hydrogen halide (HCl and HI), oxoacid (sulfuric acid, and methanesulfonic acid), super strong acid and derivatives thereof (HClO₄, CF₃SO₃H, ClSO₃H, ClSO₃H, and CH₃COClO₄), metallic oxide (silica-alumina, CrO₃ and MoO₃) and other solid acid (poly(styrene-sulfonic acid)), Nafion-H and sulfuric acid-aluminum sulfate complex) Examples of the carbenium ion salt include triphenylmethyl salt (Ph₃C⁺ Base⁻), tropylium salt (C₇H7 +Base⁻ )(Base⁻ shows SbCl6 -, SnCl5 -, PF6 - and ClO4 -). Examples of halogen include I₂ and IBr. There are also exemplified metal halides (AlCl₃, SnCl₄, SnBr₄, TiCl₄, FeCl₃, BF₃ and BCl₃), organometallic compounds (RAlCl₂, R₂AlCl, R₃Al, R₂Zn wherein R is an alkyl group such as methyl or ethyl). The radical polymerization initiators are exemplified by peroxides, azo compounds and other compounds. Examples of the peroxides include acetyl peroxide, cumyl peroxide, tert-butyl peroxide, propionyl peroxide, benzoyl peroxide, 2-chlorobenzoyl peroxide, 3-chlorobenzoyl peroxide, 4-chlorobenzoyl peroxide, 2,4-dichlorobenzoyl peroxide, 4-bromomethylbenzoyl peroxide, lauroyl peroxide, potassium persulfate, diisopropyl peroxycarbonate, tetralinhydroperoxide, 1-phenyl-2-methylpropyl-1-hydroperoxide, tert-butyl pertriphenylacetate, tert-butylhydroperoxide, tert-butyl performate, tert-butyl peracetate, tert-butyl perbenzoate, tert-butyl perphenylacetate, tert-butyl per4-methoxyacetate and tert-butyl perN-(3-tolyl)carbamate. Specific examples of the azo compounds include 2,2'-azobispropane; 2,2'-dichloro-2,2'-azobispropane; 1,1'-azo(methylethyl)diacetate; 2,2'-azobis(2-amidinopropane)hydrochloride; 2,2'-azobis(2-amidinopropane)nitrate; 2,2'-azobisisobutane; 2,2'-azobisisobutylamide; 2,2'-azobisisobutylonitrile; 2,2'-azobisisobutylonitrile/SnCl₄ (1/21.5); methyl 2,2'-azobis-2-methylpropionate; 2,2'-dichloro-2,2'azobisbutane; 2,2'-azobis-2-methylbutylonitrile; dimethyl 2,2'-azobisisobutyrate; dimethyl 2,2'-azobisisobutyrate/SnCl₄ (1/19.53); 1,1'-azobis(sodium 1-methylbutylonitrile-3-sulfonate); 2-(4-methylphenylazo)-2-methylmalonodinitrile; 4,4'-azobis-4-cyanovaleric acid; 3,5-dihydroxymethylphenylazo-2-methylmalonodinitrile; 2-(4-bromophenylazo)-2-allylmalonodinitrile; 2,2'-asobis-2-methylvaleronitrile; dimethyl 4,4-azobis-4-cyanovalerate; 2,2'-azobis-2,4-dimethylvaleronitrile; 1,1' -azobiscyclohexanenitrile; 2,2'-azobis-2-propylbutylonitrile; 1,1'-azobis-1-chlorophenylethane; 1,1' -azobis-1-cyclohexanecarbonitrile; 1,1-azobis-cycloheptanenitrile; 1,1'-azobis-1-phenylethane; 1,1'-azobiscumene; ethyl 4-nitrophenylazobenzylcyanoacetate; phenylazodiphenylmethane; phenylazotriphenylmethane; 4-nitrophenylazotriphenylmethane; 1,1'-azobis-1,2-diphenylethane; poly(bisphenolA-4,4'-azobis-4-cyanopentanoate) and poly(tetraethyleneglycol-2,2'-azobisisobutyrate). Examples of the other compounds include 1,4-bis(pentamethylene)-2-tetrazene, 1,4-dimethoxycarbonyl-1,4-diphenyl-2-tetrazene and benzene sulfonylazide. In the case of grafting α-olefin such as ethylene or propylene, styrene or cyclic olefins by the use of the catalyst comprising a transition metal and an organometal as the primary ingredients, there may be employed a compound of chromium, nickel or neodymium as the transition metal instead of the compound of the formula (4), (5), (6) or (7). As the organometal compound, the aluminoxane of the general formula (8) or (9) or the organoaluminum compound of the general formula (10) may be used. The polymerization reaction in the graft polymerization step (Step 2) according to the process of the present invention is effected by the use of the above-mentioned starting material and initiator under properly selected conditions. As the conditions of reaction of styrenic copolymer obtained in Step (1) with the initiator, the reaction temperature may be pertinently selected in the range of -100 to 200°C, preferably -80 to 120°C with the reaction time ranging from 1 second to 10 hours. The graft efficiency can be enhanced by reacting the initiator such as alkylated lithium with the styrenic copolymer obtained in the Step (1), followed by washing the unreacted residual initiator. In the case where the grafting chain and the unreacted styrenic monomer are formed into copolymerized chain, the ethylenically unsaturated monomer may be added, together with the graft initiator into the reaction system after the synthesis of the graft precursor in Step 1. The use of the catalyst which is used in Step 1 and also usable in the graft polymerization in Step 2, for example, in the case of α-olefin such as ethylene or propylene, or diolefin such as butadiene or isoprene being selected as the ethylenically unsaturated monomer, enables the graft copolymer to be produced at an extremely high efficiency. Meanwhile, the molar ratio of the initiator to the styrenic monomer II used in Step 1 is usually 1 x 10⁻⁷ to 10. The graft polymerization conditions are not specifically limited but properly determined according to various situations. As a general rule, the molar ratio of the styrenic monomer II used in Step 1 to the ethylenically unsaturated monomer to be grafted is 0.01 to 500, preferably 0.1 to 300. The polymerization temperature is properly determined in the range of -100 to 200°C, preferably -80 to 120°C with the reaction time ranging from 5 seconds to 24 hours. As the polymerization method in the aforestated Step 2, any of bulk, solution and suspension polymerization is available. The usable solvents in solution polymerization are exemplified by aliphatic hydrocarbons such as pentane, hexane and heptane, alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene, toluene and xylene, and polymerization solvents each having a hetero atom such as oxygen, nitrogen or sulfur. The solvent to be used in Step 2 may be the same as or different from that used in Step 1. Moreover, the residual unreacted monomer and the catalyst may be removed and in order to enhance the graft efficiency, a cleaning step may be put into practice. The graft copolymer obtained by the process of the present invention is the styrenic copolymer in which the stereostructure, preferably the main chain structure is of syndiotactic configuration (specifically, cosyndiotactic configuration of the repeating units derived from the styrenic monomer I and the repeating unit derived from the styrenic monomer II), particularly desirably of a high degree of syndiotactic configuration. The molecular weight of the main chain in the graft copolymer thus obtained varies depending on the polymerization conditions, etc., but the weight-average molecular weight thereof is generally 1,000 to 3,000,000, preferably 5,000 to 2,500,000 as determined by means of gel permeation chromatography(GPC) using 1,2,4-trichlororbenzene at 135°C, expressed in terms of polystyrene,. The styrenic copolymer having a high degree of the syndiotactic configuration means that its stereochemical structure is of high degree of syndiotactic configuration, i.e. the stereostructure in which phenyl groups or substituted phenyl groups as side chains are located alternately at opposite directions relative to the main chain consisting of carbon-carbon bonds. Tacticity is quantitatively determined by the nuclear magnetic resonance method (¹³C-NMR method) using carbon isotope. The tacticity as determined by the ¹³C-NMR method can be indicated in terms of proportions of structural units continuously connected to each other, i.e., a diad in which two structural units are connected to each other, a triad in which three structural units are connected to each other and a pentad in which five structural units are connected to each other. The styrene copolymers having a high degree of syndiotactic configuration as mentioned in the present invention usually means those having such a syndiotacticity that the proportion of racemic diad is at least 75%, preferably at least 85%, or the proportion of racemic pentad is at least 30%, preferably at least 50% each in the chain of the styrenic repeating units. On the other hand, the stereostructure of the graft chain of the aforestated graft copolymer is not specifically limited, but results in atactic, isotactic or syndiotactic configuration depending upon the type of the polymerization initiator and the like. The graft copolymers of the present invention thus obtained have a variety of molecular weights, and preferably are those having a content of the graft segment of 0.005 to 99% by weight and a reduced viscosity of 0.01 to 20 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. An unreasonably low reduced viscosity results in failure to sufficiently exhibit the properties of the polymer, whereas an excessively high reduced viscosity causes inferior processablility. The graft copolymer thus obtained are those wherein both the styrenic unit derived from the styrenic monomer particularly constituting the main chain (Styrenic monomer I, etc.) and the styrenic unit derived from the styrenic monomer having a hydrocarbon radical with an unsaturated bond (Styrenic monomer II) constitute a syndiotactic configuration (preferably a cosyndiotactic configuration) onto which is grafted the ethylenically unsaturated monomer (preferably the monomer having a polar group). The content of the graft monomer in the graft polymer is not always uniform varying with the monomer used, the number of grafting initiation points and the like, but usually ranges from 0.005 to 90% by weight, preferably from 0.01 to 70% by weight. The resin composition according to the present invention comprises the above-mentioned styrenic graft copolymer compounded with at least one material selected from thermoplastic resin, inorganic filler and organic filler. Various types of thermoplastic resins are available and exemplified by polyolefin resin, polystyrene resin including that of syndiotactic configuration, condensation high polymer and addition polymerization high polymer. Specific examples of polyolefin resins include high density polyethylene, low density polyethylene, poly-3-methyl-butene-1, poly-4-methyl-pentene-1, straight-chain low density polyethylene obtained by the use of such a comonomer as butene-1, hexene-1, octene-1 or 4-methylpenten-1,3-methylisobutene, ethylene/vinyl acetate copolymer, ethylene/acrylic acid copolymer ethylene/acrylic-ester copolymer, ethylenic ionomer and polypropylene. Specific examples of polystyrene resin include general-purpose polystyrene, isotactic polystyrene, syndiotactic polystyrene and high impact polystyrene (rubber modified). Specific examples of the condensation polymer include polyacetal resin, polycarbonate resin, polyamide resin such as nylon 6 and nylon 6·6, polyester resin such as polyethylene terephthalate and polybutylene terephthalate, polyphenylene oxide resin, polyimide resin, polysulfone resin, polyethersulfone resin and polyphenylene sulfide resin. Specific examples of addition polymer include a polymer consisting of polar vinyl monomers, a polymer consisting of diene monomers, enumerated by poly(methyl methacrylate), polyarylonitrile, acrylonitrile/butadiene copolymer, acrylonitrile/butadiene/styrene copolymer, a polymer having hydrogenated diene chains and thermoplastic elastomer. Each of the above-described thermoplastic resins may be used alone or in combination with at least one of others. The types of inorganic filler and organic filler to be used are not specifically restricted, but may be the known types having a variety of forms such as powder, granule, liquid, whisker and fiber. Specific examples include silica, diatomaceous earth, alumina, titanium dioxide, magnesium oxide, pumice powder, pumice balloon, aluminum hydroxide, aluminum nitride, magnesium hydroxide, basic magnesium carbonate, dolomite, calcium sulfate, potassium titanate, barium titanate, barium sulfate, calcium sulfite, talc, clay, mica, asbestos, glass fiber, glass flake, glass bead, calcium silicate, montmorillonite, bentonite, carbon black, graphite, aluminum powder, molybdenum disulfide, carbon fiber, boron fiber, silicon carbide fiber, ultrahigh molecular polyethylene fiber, polypropylene fiber, polyester fiber, polyamide fiber, Kevlar fiber, metallic fiber, and furthermore, thermosetting resin such as phenolic resin, epoxy resin and unsaturated polyester fiber, and cured powder thereof. The styrenic graft copolymer or the composition thereof according to the present invention may be subjected to the addition of at least one additive enumerated by heat resistant stabilizer, weatherproof stabilizer, antistatic agent, sliding agent, anti-blocking agent, anti-fogging agent, lubricant, foaming agent, dye, pigment, natural oil, synthetic oil and wax, in a pertinent compounding ratio. Specific examples of the stabilizers to be optionally compounded include phenolic antioxidant such as tetrakis [methylene-3(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] methane, β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionic alkylester and 2,2'-oxamindebis-[ethyl-3(3,5-di-tert-butyl-4-hydroxyphenyl)]propionate; metallic salt of fatty acid such as zinc stearate, calcium stearate and calcium 12-hydroxystearate; polyhydric alcohol-fatty acid ester such as glycerol monostearate, glycerol monolaurate, glycerol distearate, pentaerythritol monostearate, pentaerythritol distearate and pentaerythritol tristearate. Each of the aforementioned additives may be compounded alone or in combination with other additive/s, which combination being exemplified by tetrakis[methylene-3(3,5-di-tert-butyl-4-hydroxyphenyl)propionate]methane, zinc stearate and glycerol monostearate. The compounding ratio of the styrenic graft copolymer to the thermoplastic resin in the resin composition of the present invention varies with the conditions and can not be unequivocally determined, but may be usually determined according to the following standard. In the case where the thermoplastic resin is a syndiotactic polystyrene (SPS), the primary object of the resin composition is to compensate for the drawback of poor adhesion and compatibility of SPS, unnecessitating a large amount of the graft chain component, and therefore the SPS loading should be relatively low for the composition with the styrenic graft copolymer with less content of graft chain component and relatively high for the composition with much content of graft chain component. For the thermoplastic resin other than SPS, the content of the graft chain component in the styrenic graft copolymer is preferably relatively low for the purpose of making the most of the SPS characteristics. In the case where SPS and other thermoplastic resin is together added to the styrenic graft copolymer, the content of the graft chain component should be determined for the optimum range according to the combination with the resin to be used, since the copolymer functions as the compatibilizing agent for SPS and the thermoplastic resin. Taking the factors as above into consideration, as to the compounding ratio of the styrenic graft copolymer to the thermoplastic resin, the resin composition of the present invention usually comprises 0.5 to 99.5% by weight, preferably 1 to 90% by weight of the former and 99.5 to 0.5% by weight, preferably 90 to 1% by weight of the latter. In the case where the resin composition of the present invention comprises the styrenic graft copolymer and the inorganic or organic filler, the content of the former is usually 20 to 95% by weight, preferably 40 to 90% by weight, while the content of the latter is usually 80 to 5% by weight, preferably 60 to 10% by weight. In the resin composition of the present invention, the styrenic graft copolymer may be compounded with the thermoplastic resin together with the inorganic or organic filler, in this case, however, the content by weight of the sum of the copolymer and the resin is usually 20 to 95%, preferably 40 to 90%, whereas the content by weight of the filler is usually 80 to 5%, preferably 60 to 10%. The resin composition of the present invention can be prepared by various procedures, usually by the conventional melt kneading by the use of a known means such as a uniaxial or biaxial extruder, kneader, continuous mixer or mixing roll, or by means of solution blending using a suitable solvent. Moreover, the multi-layer material according to the present invention comprises at least one layer containing at least in part the above-mentioned styrenic graft copolymer and at least one layer, molding or the like made of a different material, which layers being laminated or bonded. The different material is not specifically restricted but is usually selected from a resin, metal (including alloy), ceramics (including metallic oxide), glass, paper, fiber and wood. The resin may be any of thermoplastic resin and thermosetting resin. The specific examples of the thermoplastic resins are as described hereinbefore. The specific examples of the thermosetting resins include phenolic resin, epoxy resin, unsaturated polyester resin, and fiber reinforced material therefrom. The specific examples of the metals and ceramics are as described hereinbefor. Each layer or part constituting the multi-layer material of the present invention may be in a variety of shapes and states including, for example, film, sheet, fiber (textile), moldings, sinter, single crystal, form and porous material. The method of multi-layering the materials is not specifically limited, but may be in accordance with any of the various conventional methods, exemplified by coextrusion, lamination, etc. for the different material being a thermoplastic resin. When the different material is a metal, particularly the metal to be laminated is comparetively thin, lamination, metal vapor deposition and electrostatic coating are available. When a material is laminated onto a molding or a thick material, there is available a method in which the molding or the thick material is covered with a film or sheet by heat fusion, impregnation or coating. In the multi-layer material of the present invention, at least one layer contains at least in part the aforestated styrenic graft copolymer. The layer may consist of the styrenic copolymer alone or the composition of the copolymer and the other material (thermoplastic resin and/or filler). In particular, the composition of the present invention may be applied to the composition with other material. The multi-layer material of the present invention may be in a variety of shapes and states and comprises the layers of film, sheet, fiber, moldings, sinter, single crystal, foam or porous material, the surface of which contains at least in part the styrenic graft copolymer, said layers being laminated or covered by impregnation or coating, etc. or comprises the complex material thereof. The styrenic copolymer of the present invention is greatly improved in terms of compatibility, adhesivity and wettability while particularly preserving the heat resistance and chemical resistance inherent to SPS. Accordingly, it facilitates the production of a composite material with other resin, glass fiber, filler such as talc, ceramics and metal, enabling the application and development of the syndiotactic styrenic resin in the field of composite materials as well as the effective utilization thereof as a modifier and compatibilizing agent for a variety of resins. Furthermore, the composition or multi-layer material according to the present invention is widely utilized in various application fields including film, sheet, especially stampable sheet, container, packaging material, automobile parts, electrical and electronic parts. In the following, the present invention will be described in more detail with reference to the examples. Example 1(1) Preparation of methylaluminoxaneIn a 500 ml glass vessel which had been purged with argon were placed 200 ml of toluene, 17.7g (71 mmol) of copper sulfate pentahydrate (CuSO₄·5H₂O) and 24 ml (250 mmol) of trimethylaluminum, which were then reacted at 40°C for 8 hours. Then, the solids were separated from the reaction mixture and the toluene was distilled away from the solution as obtained above under reduced pressure to obtain 6.7g of a contact product. The molecular weight thereof as determined by the freezing point depression method was 610. Further, when the area of the high magnetic field component by ¹H-NMR spectral analysis based on Japanese Patent Application Laid-Open No.325391/1987, that is, the proton nuclear magnetic resonance spectral of the methylaluminoxane in toluene soluent at room temperature was observed, the methyl proton signal due to Al-CH₃ was observed in the region of 1.0 to -0.5 ppm (tetramethylsilane (TMS) standard). Since the proton signal of TMS (0 ppm) was in the region of methyl proton signal due to Al-CH₃, the methyl proton signal due to Al-CH₃ was measured with 2.35 ppm methyl proton signal of toluene in TMS, and the methyl proton signal due to Al-CH₃ was divided into two components. As the result, the high magnetic field component (i.e -0.1 to -0.5 ppm) was 43% of the total signal area. (2) Production of p-methylstyrene/divinylbenzene copolymerIn a 0.5 L (L=liter) reaction vessel equipped with a stirrer which had been purged with nitrogen followed by heating to 70°C, was placed a mixture of 50 ml of sufficiently dried toluene, 50 ml of p-methylstyrene and 3.0 ml of a monomer containing 66.1% by weight of divinylbenzene (meta-, para- mixture) and 33.9% by weight of ethylstyrene (meta-, para- mixture), and were further placed 1.5 mM of methylaluminoxane obtained in the preceding item (1) and 1.5 mM of triisobutylaluminum (TIBA) with stirring for 30 minutes. Then, 0.003 mM of pentamethylcyclopentadienyltitanium trimethoxide was added to the resultant mixture to effect reaction for 2 hours. Thereafter, 1/10 of the reaction product was taken out under uniform state with stirring and the reaction was arrested by methanol injection. subsequently, a mixture of HCl and methanol was added to decompose the catalyst component. The resultant styrenic copolymer was washed with methyl ethyl ketone (MEK) containing 2% by weight of p-tert-butylcatechol at 50°C for 2 hours, and the insoluble content was 99%. The MEK-insoluble styrenic copolymer was dissolved in chloroform to produce a solution of the styrenic copolymer in chloroform. The styrenic copolymer soluble in chloroform had a weight-average molecular weight of 658,000 and a number-average molecular weight of 180,000. Here, it will be proved that the styrenic copolymer thus obtained was a heat-sensitive copolymer having syndiotactic configuration from the results of infrared spectroscopic analysis (IR) and nuclear magnetic resonance (NMR) analysis. (a) IR analysis In the IR spectrum of the styrene copolymer, a peak assigned to the double bond remaining in the polymerization site of the divinylbenzene was confirmed at 1630 cm⁻¹. (b) NMR analysis As the result of a ¹³C-NMR analysis of the styrenic copolymer, aromatic ring C₁ carbon signals were observed at 145.1 ppm, 144.9 ppm and 142.3 ppm, proving that the stereostructure of the copolymer was syndiotactic. (3) Graft polymerization of methyl methacrylate (MMA) The aforementioned p-methylstyrene/divinylbenzene copolymer was washed with 200 ml of toluene 3 times to remove the unreacted monomer and catalyst, followed by adding toluene to make the total volume of 300 ml. Then, 4 mM of n-butyllithium (n-BuLi) was added to effect reaction at room temperature for 8 hours. the reaction product was washed with 200 ml of toluene 3 times to remove the unreacted n-BuLi, followed by adding toluene to make the total volume of 300 ml. Thereafter, the reaction system was rapidly cooled with dry ice/methanol at -78°C, and 20 ml of MMA was added dropwise to effect reaction for 8 hours. Then, the reaction was arrested by methanol injection. The MMA-grafted styrenic copolymer was obtained at a yield of 4.2g. In the IR spectrum of the copolymer, a peak assigned to the double bond (C=0) of MMA was confirmed at 1730 cm⁻¹. Also, the disappearance of the peak assigned to the double bond of divinylbenzene was confirmed at 1630 cm⁻¹. The graft copolymer thus obtained had a reduced viscosity of 1.98 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. As a result of ¹³C-NMR analysis of the copolymer in 1,2,4-trichlorobenzene at 135°C, aromatic signals assigned to SPS were observed at 145.4 ppm, proving the syndiotactic configuration of the styrenic chain. In addition, the copolymer had a tacticity of 95% in terms of racemic diad as measured by ¹³C-NMR analysis and a ratio by weight of p-methylstyrene to MMA of 1:2.75 as measured by NMR analysis. Example 2 The procedure in Example 1 (2) and (3) was repeated except that styrene was used in place of p-methylstyrene in producing styrenic copolymer to produce MMA-grafted styrene/divinylbenzene copolymer at a yield of 5.8g. In the IR spectrum of the graft copolymer, a peak assigned to the double bond (C=0) of MMA was confirmed at 1730 cm⁻¹. The graft copolymer had a reduced viscosity of 1.98 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. In addition, the graft copolymer had a tacticity of 95% in terms of racemic diad as measured by ¹³C-NMR analysis and a ratio by weight of styrene to MMA of 1:2.82 as measured by NMR analysis. Example 3 The procedure in Example 2 was repeated except that acrylonitril was used in place of MMA in the graft polymerization to produce acrylonitrile-grafted styrene/divinylbenzene copolymer at a yield of 25.2g. In the IR spectrum of the copolymer, a peak assigned to the acrylonitrile was confirmed at 2240 cm⁻¹. The graft copolymer had a reduced viscosity of 1.94 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. In addition, the graft copolymer had a tacticity of 95% in terms of racemic diad as measured by ¹³C-NMR analysis, and a ratio by weight of styrene to acrylonitrile of 1:15.8 as measured by NMR analysis. Example 4The procedure in Example 2 was repeated except that isoprene was used in place of MMA and the graft polymerization was effected at 50°C to produce isoprene-grafted styrene/divinylbenzene copolymer at a yield of 12.3g. In the IR spectrum of the graft copolymer, peaks assigned to the isoprene were confirmed at 840 cm⁻¹, 1380 cm⁻¹ and 2960 cm⁻¹, respectively. The graft copolymer had a reduced viscosity of 1.87 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. In addition, the graft copolymer had a tacticity of 95% in terms of racemic diad as measured by ¹³C-NMR analysis, and a ratio by weight of styrene to isoprene of 1:7.20 as measured by NMR analysis. Example 5The procedure in Example 2 was repeated except that butadiene was used in place of MMA and the graft polymerization was effected at 50°C to produce butadiene-grafted styrene/divinylbenzene copolymer at a yield of 8.4g. In the IR spectrum of the graft copolymer, a peak assigned to the butadiene was confirmed at 960 cm⁻¹. The graft copolymer had a reduced viscosity of 1.89 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. In addition, the graft copolymer had a tacticity of 95% in terms of racemic diad as measured by ¹³C-NMR analysis, and a ratio by weight of styrene to butadiene of 1:4.60 as measured by NMR analysis. Example 6The procedure in Example 2 was repeated except that tetraethoxytitanium (TET) was used as the catalyst in place of pentamethylcyclopentadienyltitanium trimethoxide in the copolymer production to produce MMA-grafted styrene/divinylbenzene copolymer at a yield of 3.5 g. In the IR spectrum of the graft copolymer, a peak assigned to the double bond (C=0) of MMA was confirmed at 1730 cm⁻¹. The graft copolymer had a reduced viscosity of 2.00 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. In addition, the graft copolymer had a tacticity of 95% in terms of racemic diad as measured by ¹³C-NMR analysis, and a ratio by weight of styrene to MMA of 1:2.18 as measured by NMR analysis. Example 7The procedure in Example 2 was repeated except that hexane was used as the polymerization solvent in place of toluene to produce MMA-grafted styrene/divinylbenzene copolymer at a yield of 5.6g. In the IR spectrum of the graft copolymer, a peak assigned to the double bond (C=0) of MMA was confirmed at 1730 cm⁻¹. The graft copolymer had a reduced viscosity of 2.01 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. In addition, the graft copolymer had a tacticity of 95% in terms of racemic diad as measured by ¹³C-NMR analysis, and a ratio by weight of styrene to MMA of 1:4.09 as measured by NMR analysis. Example 8The procedure in Example 2 was repeated except that heptane was used as the polymerization solvent in place of toluene to produce MMA-grafted styrene/divinylbenzene copolymer at a yield of 8.1g. In the IR spectrum of the graft copolymer, a peak assigned to the double bond (C=0) of MMA was confirmed at 1730 cm⁻¹. The graft copolymer had a reduced viscosity of 2.05 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. In addition, the graft copolymer had a tacticity of 95% in terms of racemic diad as measured by ¹³C-NMR analysis, and a ratio by weight of styrene to MMA of 1:6.36 as measured by NMR analysis. Example 9The procedure in Example 2 was repeated except that azobisisobutyronitrile (AIBN) was used as the catalyst in place of n-BuLi in the graft reaction to produce MMA-grafted styrene/divinylbenzene copolymer at a yield of 3.1g. In the IR spectrum of the graft copolymer, a peak assigned to the double bond (C=0) of MMA at 1730 cm⁻¹. The graft copolymer had a reduced viscosity 2.07 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. In addition, the graft copolymer had a tacticity of 95% in terms of racemic diad as measured by ¹³C-NMR analysis, and a ratio by weight of styrene to MMA of 1:1.82 as measured by NMR analysis. Example 10In a 200 ml reaction vessel were placed 70 ml of toluene, 60 ml of styrene and 2 ml of p-divinylstyrene in an argon atmosphere at room temperature, and further placed 10 mmol of methylaluminoxane as prepared in Example 1 (1). The mixture was heated to 50°C. Then, 0.1 mmol of tetraethoxytitanium was added to the mixture to effect copolymerizing reaction for one (1) hour, 5 ml of the reaction product was dispensed in argon atmosphere from the reaction system and transferred to a pressure-glass reaction vessel. The resultant copolymerized powder was washed 3 times by decantation with 100 ml of hexane and 200 ml of hexane was added thereto at the last stage. To the mixture was added 2 mmol of diethylaluminum monochloride and ethylene was introduced into the vessel at 70°C and 2.4 kg/cm²G for 3 hours. After pressure release, the graft copolymer thus obtained was cleaned by pouring into methanol, and air-dried to provide 2.85g of graft copolymer. In order to prove that the resultant copolymer was an ethylene-grafted copolymer having syndiotactic polystyrene as the main chain, the following analysis was carried out. Firstly IR analysis and ¹³C-NMR analysis were performed for the graft precursor. As the result, the absorption of the vinyl group of divinylbenzene residue was observed at 1630 cm⁻¹, and the ratio of absorbance of vinyl group at 1630 cm⁻¹ to absorbance of styrene residue at 1605 cm⁻¹, (D₁₆₃₀/D₁₆₀₅) was 0.26. Also, ¹³C-NMR analysis showed a sharp peak assigned to quaternary carbon atom of aromatic ring at 145.2 ppm, proving that the styrene chain was of syndiotactic configuration. As the result of IR analysis for the graft copolymer, absorption assigned to methylene chain was observed at 720 cm⁻¹ and 730 cm⁻¹, the absorbance of vinyl group derived from divinylbenzene residue decreased, and D₁₆₃₀/D₁₆₀₅ ratio also decreased to 0.16. Thus the formation of the graft copolymer has been proved by the above facts. Further, in order to obtain the graft copolymer composition, IR analysis was conducted with various compounding ratios of high density polyethylene to SPS to prepare a calibration curve from the ratio of absorbance at 720 cm⁻¹ to that at 1605 cm⁻¹. The graft copolymer had a ratio by weight of styrene to ethylene of 1:1.03 as determined with the calibration curve thus prepared and a reduced viscosity of 1.66 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. Example 11(1) Preparation of tri(n-butyl)ammonium tetra-(pentafluorophenyl)boratePentafluorophenyllithium which was prepared from 152 mmol of bromopentafluorobenzene and 152 mmol of butyllithium was reacted with 45 mmol of trichloroboron in hexane to produce tri(pentafluorophenyl)boron as white solid, 41 mmol of which was reacted with 41 mmol of pentafluoropenyllithium to produce lithium tetra(pentafluorophenyl)boron as white solid and isolate the same. Then, 16 mmol of lithium tetra(pentafluorophenyl)boron was reacted with 16 mmol of tri-n-butylamine hydrochloride in water to produce 12.8 mmol of tri(n-butyl)ammonium tetra(pentafluorophenyl)borate as white solid. (2) Production of styrene/divinylbenzene copolymerIn a 100 ml reaction vessel dried and made of stainless steel were placed 20 ml of styrene and 1.2 ml of divinylbenzene (the compound as described in Example 1) in argon atmosphere, and further placed 0.03 mmol of triisobutylaluminum (TIBA), and the mixture was maintained at 70°C for 30 minutes. Into the reaction vessel were further introduced 0.5 µmol of tri(n-butyl)ammonium tetra(pentafluorophenyl)borate as prepared in the above item (1) and 0.5 µmol of pentamethylcyclopentadienyltrimethyltitanium to initiate copolymerization with stirring. After 2 hours of copolymerization, 30 ml of dry toluene was added to the reaction system to form slurry state, and a small amount of the reaction product was sampled to perform IR analysis and ¹³C-NMR analysis. As the result of IR analysis, the absorption of the vinyl group in divinylbenzene residue was observed at 1630 cm⁻¹, and the ratio of absorbance of vinyl group at 1630 cm⁻¹ to absorbance of styrene residue at 1605 cm⁻¹, (D₁₆₃₀/D₁₆₀₅) was 0.31. Moreover, ¹³C-NMR analysis exhibited a sharp peak assigned to quaternary carbon atom of aromatic ring at 145.2 ppm, demonstrating the syndiotactic configuration of the styrene chain. In order to continue the graft polymerization, ethylene was continuously introduced into the reaction system at 70°C and at 9 kg/cm²G for 10 hours. Subsequently, the pressure was released, and the graft copolymer thus obtained was cleaned by pouring into methanol and air-dried to give an amount of 4.86g. As the result of IR analysis of the resultant graft copolymer, absorption assigned to the methylene chain was observed at 720 cm⁻¹ and 730 cm⁻¹, the absorbance of vinyl group derived from divinylbenzene residue decreased, and D₁₆₃₀/D₁₆₅₀ ratio also decreased to 0.18. Thus, the formation of the graft copolymer has been demonstrated by the aforestated facts. Further, in order to obtain the copolymeric composition, IR analysis was carried out with various compounding ratios of high density polyethylene to SPS to prepare a calibration curve from the ratio of absorbance at 720 cm⁻¹ to that at 1605 cm⁻¹. The graft copolymer had a ratio by weight of styrene to ethylene of 1:0.07 as determined with the calibration curve thus prepared, and a reduced viscosity of 1.34 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. Example 12In a 0.5 L reaction vessel equipped with a stirrer which had been purged with nitrogen followed by heating to 70°C, were placed a mixture of 50 ml of sufficiently dried toluene, 50 ml of styrene and 0.1 ml of a monomer containing 66.1% by weight of divinylbenzene (meta-, para- mixture) and 33.9% by weight of ethylstyrene (meta-, para- mixture), and further placed 1.5 mmol of methylaluminoxane obtained in Example 1, item (2) and 1.5 mmol of triisobutylaluminum (TIBA) with stirring for 30 minutes. Then, 0.003 mmol of pentamethylcyclopentadienyltitanium trimethoxide was added to the resultant mixture to effect reaction for 2 hours. After the completion of reaction, a large amount of hexane was poured into the system to clean the graft copolymer thus produced by means of decantation. Thereafter, the total volume of the system was adjusted to 100 ml, and a solution of 3.0 mmol of n-butyllithium in hexane at 50°C was added to the system to effect reaction for 2 hours. After the reaction, unreacted n-butyllithium was washed away by decantation in the same manner as above. The graft copolymer thus obtained was cooled to -78°C, to which were added hexane to make a total volume of 100 ml and 30 ml of glycidyl methacrylate to effect graft polymerization for 12 hours. After the completion of reaction, the graft copolymer thus obtained was cleaned by pouring into a large amount of methanol, air-dried to give an amount of 7.8g and subjected to Soxhlet extraction by the use of MEK as the extraction solvent to leave 93% of insoluble portion. The graft copolymer as the above-mentioned MEK insoluble portion had a reduced viscosity of 1.47 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. By the use of a differential scanning calorimeter (available from Seiko Electronics Co., Ltd. under the trademark DSC-200 ), 5.7 mg of the graft copolymer sample was heated from 50°C to 310° at a rate of 20°C/minute, then allowed to cool from 310°C to 30°C at a rate of 20°C/minute and repeatedly heated from 30°C to 315°C at the same rate as above to observe the endothermic pattern. As the result, it was confirmed that the aforestated graft copolymer had a melting point at 263°C. In addition, it had a syndiotacticity of 95% on higher in terms of racemic pentad as measured by ¹³C-NMR analysis, and a composition of 55% by weight of styrene unit and 45% by weight of glycidyl methacrylate unit, as measured by ¹H-NMR analysis. Example 13The procedure in Example 12 was repeated except that glycidyl methacrylate was used in a loading of 2 ml in place of 30 ml to synthesize a graft copolymer. After the completion of reaction, the graft copolymer thus obtained was cleaned by pouring into a large amount of methanol, air-dried to give an amount of 6.73g and subjected to Soxhlet extraction by the use of MEK as the extraction solvent to leave 97% of MEK insoluble portion. The graft copolymer as the above-mentioned MEK insoluble portion had a reduced viscosity of 1.53 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C By the use of a differential scanning calorimeter (available from Seiko Electronics Co, Ltd. under the trademark DSC-200 ), 5.7 mg of the graft copolymer sample was heated from 50°C to 310°C at a rate of 20°C/minute, then allowed to cool from 310°C to 30°C at the same rate as above and repeatedly heated from 30°C to 310°C at the same rate as above to observe the endothermic pattern. As the result, it was confirmed that the aforestated graft copolymer had a melting point at 263°C. It was also proved that the graft copolymer had a syndiotacticity of 95% or higher in terms of racemic pentad as measured by ¹³C-NMR analysis and a composition of 92% by weight of styrene unit and 8 by weight of glycidyl methacrylate unit as measured by ¹H-NMR analysis. Example 14The procedure in Example 12 was repeated except that 2g of maleic anhydride together with 2.1g of styrene was used in place of glycidyl methacrylate, 50 mg of benzoyl peroxide was used as the polymerization initiator in place of n-buthyllithium and the graft polymerization was effected at 70°C for 4 hours to synthesize a graft copolymer. After the completion of polymerization, the graft copolymer thus obtained was cleaned by pouring into a large amount of methanol, air-dried to give an amount of 6.0g and subjected to Soxhlet extraction by the use of MEK as the extraction solvent to leave 98% of insoluble portion. The graft copolymer as the above-mentioned MEK insoluble portion had a reduced viscosity of 1.37 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. By the use of a differential scanning calorimeter (available from Seiko Electronics Co., Ltd. under the trademark DSC-200 ), 5.7 mg of the graft copolymer sample was heated from 50°C to 310°C at a rate of 20°C/minute, then allowed to cool from 310°C to 30°C at a rate of 20°C/minute and repeatedly heated from 30°C to 315°C at the same rate as above to observe the endothermic pattern. As the result, it was confirmed that the aforestated graft copolymer had a melting point at 263°C. In addition, it had a syndiotacticity of 93% or higher in terms of racemic pentad as measured by ¹³C-NMR analysis, and a composition of 97% by weight of styrene unit and 3% by weight of maleic anhydride unit as measured by ¹H-NMR analysis. Example 15In a 0.5 L reaction vessel equipped with a stirrer which had been purged with nitrogen followed by heating to 70°C, were placed a mixture of 300 ml of sufficiently dried toluene, 200 ml of styrene and 30 ml of p-(4-pentenyl)styrene, and further placed 12 mmol of aluminoxane and 12 mmol of TIBA with stirring for 30 minutes. Then, 15 µmol of pentamethylcyclopentadienyltitanium trimethoxide was added to the resultant mixture to effect copolymerization for 2 hours. After the completion of copolymerization, the copolymer thus obtained was cleaned by pouring into a large amount of methanol, air-dried to give an amount of 0.5g and subjected to Soxhlet extraction by the use of MEK as the extraction solvent to leave 98% of insoluble portion. The copolymer as the above-mentioned MEK insoluble portion had a reduced viscosity of 2.00 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. By the use of a differential scanning calorimeter (available from Seiko Electronics Co., Ltd. under the trademark DSC-200 ), 5.7 mg of the copolymer sample was heated from 50°C to 310°C at a rate of 20°C/minute, then allowed to cool from 310°C to 30°C at a rate of 20°C/minute and repeatedly heated from 30°C to 315°C at the same rate as above to observe the endothermic pattern. As the result, it was confirmed that the aforestated copolymer had a melting point at 245°C. In addition, it had a syndiotacticity of 92% or higher in terms of racemic pentad as measured by ¹³C-NMR analysis. In the IR spectrum of the copolymer, a stretching vibration of carbon-carbon double bond based on the styrene unit was observed at 1630 cm⁻¹, proving that the styrenic copolymerization had proceeded mainly at the olefinic skeleton of p-(4-pentenyl)styrene. 5g of the copolymer was dispersed in 100 ml of toluene in an argon atmosphere, to which was added 10 ml of glycidyl methacrylate to produce graft copolymer in the same manner as Example 12. After the completion of graft polymerization, the graft copolymer thus obtained was cleaned by pouring into a large amount of methanol, air-dried to give 6.5g of graft copolymer, and subjected to Soxhlet extration by the use of MEK as the extraction solvent to leave 96% of insoluble portion. The graft copolymer as the above-mentioned MEK insoluble portion had a reduced viscosity of 2.10 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. By the use of a differential scanning calorimeter (available from Seiko Electronics Co., Ltd. under the trademark DSC-200 ), 5.7 mg of the graft copolymer sample was heated from 50°C to 310°C at a rate of 20°C/minute, then allowed to cool from 310°C to 30°C at a rate of 20°C/minute and repeatedly heated from 30°C to 315°C at the same rate as above to observe the endothermic pattern. As the result, it was confirmed that the aforestated graft copolymer had a melting point at 244°C. In addition, it had a syndiotacticity of 91% or higher in terms of racemic pentad as measured by ¹³C-NMR analysis, and a composition of 80% by weight of styrene unit and 20% by weight of glycidyl methacrylate unit as measured by ¹H-NMR analysis. In the IR spectrum of the graft copolymer, the absorption bond at 1630 cm⁻¹ disappeared, proving the formation of graft copolymer. Example 16-1(1) Production of styrene/divinylbenzene copolymer (graft precursor)In a 4.0 L reaction vessel equipped with a stirrer which had been purged with nitrogen followed by heating to 70°C, were placed a mixture of 250 ml of sufficiently dried toluene, 1000 ml of styrene and 0.1 ml of a monomer containing 66.1% by weight of divinylbenzene (m-, p- mixture) and 33.9% by weight of ethylstyrene (m-, p- mixture), and further placed 8.5 mmol of methylaluminoxane and 8.5 mmol of TIBA obtained in Example 1 (1) with stirring for 30 minutes. Then, 0.043 mmol of pentamethylcyclopentadienyltitanium trimethoxide was added to the resultant mixture to effect reaction for 5 hours. Thereafter the reaction was arrested by methanol injection and the reaction system was washed with acetic acid/methanol to decompose the catalyst composition. The resultant styrenic copolymer was washed with methyl ethyl ketone (MEK) containing 2% by weight of p-tert-butylcatechol at 50°C for 4 hours, and the insoluble content was 97%. The MEK-insoluble styrenic copolymer was dissolved in chloroform to produce a solution of the styrenic copolymer in chloroform. The styrenic copolymer soluble in chloroform had a weight-average molecular weight of 724,000 and a number-average molecular weight of 243,000. As the result of differential scanning calorimetry using a differential scanning calorimeter (available from Perkin Elmer Corp. under the trademark DSC-II ), it was confirmed that the copolymer had a melting point at 268°C, a glass transition point at 98°C. Also, as the result of ¹³C-NMR analysis, aromatic ring C₁ carbon signals were observed at 145.2 ppm, proving the syndiotactic configuration of the resultant copolymer. In the IR spectrum, the absorption of vinyl group in divinylbenzene residue was observed. (2) Graft polymerization with n-phenyl maleimide (nPMI)The styrene-divinylbenzene copolymer obtained in the above procedure (1) was washed with toluene, further washed with methanol sufficiently, dried at 40°C under reduced pressure, placed in a 1 L reactor equipped with a stirrer in an amount of 140g, and the space in the reactor was replaced with nitrogen. Then, 420 ml of sufficiently dried toluene was added to the system under heating to 50°C and gentle stirring. After one hour, a solution of 45.9g of nPMI in 200 ml of sufficiently dried THF and a solution of 2.13 g of azobisisobutyronitrile (AIBN) as a radical initiator in 30 ml of sufficiently dried THF were added to the system, which was heated to 70°C to effect graft polymerization for 5 hours. Thereafter, the graft polymerization was arrested by methanol injection and the system was sufficiently washed with acetone as the solvent suitable for nPMI and N,N-dimethylformamide as the solvent suitable for poly-nPMI. After the completion of reaction, the reaction product was cleaned by pouring into a large amount of methanol, air-dried to give 163g of copolymer as the insoluble content of 90%. The graft copolymer had a reduced viscosity of 1.30 dl/g as measured at a concentration of 0.05g/dl in 1,2,4-trichlorobenzene at 135°C. By the use of a differential scanning calorimeter (available from Seiko Electronics Co., Ltd. under the trademark DSC-200 ), 5.7 mg of the copolymer sample was heated from 50°C to 310°C at a rate of 20°C/minute, then allowed to cool from 310°C to 30°C at the same rate as above and repeatedly heated from 30°C to 310°C at the same rate as above to observe the endothermic pattern. As the result, it was confirmed that the graft copolymer had a melting point at 265°C. In addition, as the result of ¹³C-NMR analysis, aromatic signals assigned to syndiotactic configuration were observed at 145.4 ppm with the syndiotacticity of 94% or higher in terms of racemic pentad. The content of nPMI in the above graft copolymer was proved to be 8% by weight by ¹H-NMR analysis. In IR spectrum, the peak at 1630 cm⁻¹ assigned to the double bond of divinylbenzene disappeared and a new peak attributable to (C=0) of nPMI appeared at 1710 cm⁻¹. Examples 16-2 to 16-14The procedure in Example 16-1 was repeated except the conditions given in Table 1. In the case where the monomer was α-methylstyrene in the graft polymerization, the precursor was added to 600 ml of n-heptane and after cooling to -78°C, to the resultant mixture were added 5 ml of solution of triethyloxonium tetrafluoroborate in methylene chloride (1 mol/L) and sufficiently dried α-methylstyrene with gentle stirring to effect graft polymerization for 6 hours. In the case where the monomer was norbornene in the graft polymerization, the precursor was added to 420 ml of toluene and after heating to 50°C, to the resultant mixture were added 0.75 ml of nickel acetylacetonate solution (0.02 mol/L), 3 mmol of methylaluminoxane and solution of norbornene in toluene (6.7 mol/L) with gentle stirring to effect graft polymerization for 6 hours. In Examples 16-1, 16-10 and 16-14, the styrenic graft copolymer was pelletized by the use of a biaxial kneader at a cylinder temperature of 300°C, injection molded at 300°C to Produce test pieces and further, the test pieces were heat treated at 230°C for 10 minutes. The resultant test pieces were tested for heat distortion temperature (HDT; JIS-K7270) and for flexural modulus of elasticity (JIS-K7203) with the results given in Table 1. As the standard physical properties, SPS had a heat distortion temperature of 100.3°C and a flexural modulus of elasticity of 39,500 kg/cm². Example 17 and Comparative Examples 1 to 3By the use of the styrenic graft copolymers obtained in Examples 12 and 14, the resins having the compounding ratios shown in Table 2 were prepared and kneaded at 300°C for 5 minutes with a miniature molding machine (available from Custom Scientific Instrument Inc, Model CS-183 ) followed by extrusion to produce strands. Figures 1 to 7 are each an electron micrograph (x 1000 magnification) showing the rupture cross-section of each of the strands thus obtained. Examples 18 and Comparative Examples 4 to 6The procedure in Example 17 was repeated except that the styrenic graft copolymers obtained in Examples 16-4, 16-7 and 16-14 were used and kneaded according to the compounding ratios shown in Table 3. The results are shown in Table 3 and Figures 8 to 14. In Examples 18-1 and 18-2 and Comparative Examples 5, the test pieces which were injection molded according to Example 16-1 were tested for heat distortion temperature and flexural modulus of elasticity. The results are given in Table 4. No. Heat distortion temperature (°C) Flexural modulus of elasticity (kg/cm²) Example 18-1115.548,600 Example 18-5114.946,900 Comparative Example 5102.840,800 Example 1970 wt% of resin compound comprising 20 wt% of styrenic graft copolymer obtained in Example 12 and/or 14 and 80 wt% of SPS, and 30 wt% of chopped glass fiber strand of 3mm in length were melt blended at 300°C to produce glass-fiber reinforced resin composition. Sufficient adhesion of the resin to the glass fiber was recognized by observing the rupture cross section of the composition. Example 2040 mg of the styrenic graft copolymer (glycidyl methacrylate unit of 45 wt%) obtained in Example 12 was sandwiched between two aluminum sheets (50 µm thick, 15 mm wide) so as to form an adhesive surface of 15 mm by 15 mm, and the resultant laminate was heated at 300°C for 2 minutes followed by pressing for one minute at 10 kg/cm² to form a multi-layer material. A test piece of the multi-layer material thus obtained was tested for adhesive strength under shear at a pull rate of 20 mm/minute with the result of 30.5 kg/(15 mm x 15 mm). The results obtained by the use of copper sheets and glass sheets in place of aluminum sheets were 28.0 kg/(15 mm x 15 mm) and 35.0 kg/(15 mm x 15mm), respectively. On the other hand, both SPS and styrene/divinylbenzene copolymer sandwiched in the same manner as above failed to cause adhesion. Example 21The procedure in Example 19 was repeated except that the styrenic graft copolymer obtained in Example 13 (glycidyl methacrylate unit of 8 wt%) were used to produce a multi-layer material, a test piece of which was tested for adhesive strength under shear at a pull rate of 20 mm/minute. The result was 29.0 kg/(15 mm x 15 mm). The results obtained by the use of copper sheets and glass sheets in place of aluminum sheets were 26.0 kg/(15 cm x 15 cm) and 31.0 kg/(15 mm x 15 mm), respectively. Example 22The resin compositions obtained in Example 17 and Comparative Example 1 to 3 were compounded according to the composition in Table 5 and press molded at 300°C to form each sheet of 50 mm x 50 mm x 0.5 mm in size. Each of the sheets thus obtained was press molded for 5 minutes at the temperature shown in Table 5, at a pressure of 0.5 kg/cm² to produce a multi-layer material. The results are also given in Table 5. Resin Composition Substrate Lamination temperature (°C) Laminated condition Example 17-1Aluminum300Good Example 17-2Copper300Good Example 17-3Aluminum300Good Example 17-4Nylon 6·6240Good Comparative Example 1Aluminum300Cracking in resin layer Comparative Example 2Copper300Cracking in resin layer Comparative Example 3Nylon 6·6240Interlaminar separation | A process for producing a styrenic graft copolymer which comprises copolymerizing a styrenic monomer and a styrenic monomer having a hydrocarbon radical with an unsaturated bond in the presence of a catalyst comprising as primary ingredients (A) at least one transition metal compound selected from the group consisting of titanium, zirconium hafnium and vanadium compounds and (B) a contact product of an organoaluminum compound and a condensation agent and subsequently graft polymerizing an ethylenically unsaturated monomer onto the resultant styrenic copolymer. A process for producing a styrenic graft copolymer which comprises copolymerizing a styrenic monomer and a styrenic monomer having a hydrocarbon radical with an unsaturated bond in the presence of a catalyst comprising as primary ingredients (A) at least one transition metal compound selected from the group consisting of titanium, zirconium hafnium and vanadium compounds and (C) a compound represented by the following formula ([L1-H ]u+ v([M5X1X2 --- Xs](s-t)-)i or ([L2]u+)v([M6X1X2 --- Xs](s-t)-)i wherein L² is M⁷, R²¹ R²² M⁸ or R233 c; L¹ is a Lewis base; M⁵ and M⁶ are each an element selected from Groups of VB, VIB, VIIB, VIII, IB, IIB, IIIA, IVA and VA of the Periodic Table; M⁷ is a metal selected from Groups IB, IIB and VIII of the Periodic Table; M⁸ is a metal selected from Group VIII of the Periodic Table; X¹ to Xs are each a hydrogen atom, dialkylamino group, alkoxyl group, aryloxyl group, alkyl group having 1 to 20 carbon atoms, aryl group having 6 to 20 carbon atoms, alkylaryl group, arylalkyl group, substituted alkyl group, organometalloid group or halogen atom; R²¹ and R²²are each cyclopentadienyl group, substituted cyclopentadienyl group, indenyl group or fluorenyl group; R²³ is a hydrocarbon radical; t is the valency of each of M⁵ and M⁶ indicating an integer of 1 to 7; s is an integer of 2 to 8; u is the ion valency of each of [L¹-H] and [L²], indicating an integer of 1 to 7; v is an integer of 1 or greater; and i = u x v/(s-t), and subsequently graft polymerizing an ethylenically unsaturated monomer onto the resultant styrenic copolymer. The process according to claim 2 wherein the compound (C) is selected from trityl tetraphenylborate or trityl tetra(pentafluorophenyl)borate. The process according to Claim 1 or 2, wherein said styrenic copolymer has syndiotactic configuration. The process according to any of the preceding claims, wherein said styrenic monomer is a styrenic monomer I represented by the general formula (1) wherein R¹ is a hydrogen atom, a halogen atom or a substituent having at least one atom selected from carbon, oxygen, nitrogen, sulfur, phosphorus, selenium, silicon and tin, m is an integer from 1 to 3 and when m is 2 or 3, each R¹ may be the same or different; said styrenic monomer having a hydrocarbon radical with an unsaturated bond is a styrenic monomer II represented by the general formula (2) wherein R² is a hydrocarbon radical with an unsaturated bond, n is an integer of 1 or 2, and R¹ and m are as previously defined; and said ethylenically unsaturated monomer is a monomer represented by the general formula (3) wherein Q¹, Q², Q³ and Q⁴ are each a hydrogen atom, a halogen atom or a substituent having at least one atom selected from carbon, oxygen, nitrogen, sulfur, phosphorus, selenium, silicon and tin, and may be the same or different The process according to any of the preceding claims, wherein said ethylenically unsaturated monomer is a monomer selected from the group consisting of (1) acrylic acid, methacrylic acid and derivatives thereof, (2) acrylamide, methacrylamide and derivatives thereof, (3) vinyl acetate and derivatives thereof, (4) cinnamic acid, crotonic acid and derivatives thereof, (5) acrylonitrile, methacrylonitrile and derivatives thereof, (6) maleic acid, fumaric acid, maleic anhydride and derivatives thereof, (7) maleimide and derivatives thereof, (8) itaconic acid, itaconic anhydride and derivative thereof, (9) acroleins, (10) vinyl ketones, (11) diolefins, (12) styrene and derivatives thereof, (13) α-olefins and (14) cyclic olefins. A styrenic graft copolymer having syndiotactic configuration produced by graft polymerizing an ethylenically unsaturated monomer onto a copolymer of a styrenic monomer and a styrenic monomer having a hydrocarbon radical with an unsaturated bond. The styrenic graft copolymer having syndiotactic configuration according to Claim 7, wherein said ethylenically unsaturated monomer is a monomer having a polar group. The styrenic graft copolymer having syndiotactic configuration according to Claim 7 or 8, wherein said graft copolymer has a graft segment content of 0.005 to 99% by weight and a reduced viscosity of 0.01 to 20 dl/g as measured at a concentration of 0.05 g/dl in 1,2,4-trichlorobenzene at 135°C. A resin composition which comprises a styrenic graft copolymer produced by graft copolymerizing an ethylenically unsaturated monomer onto a copolymer of a styrenic monomer and a styrenic monomer having a hydrocarbon radical with an unsaturated bond and at least one member selected from a thermoplastic resin, an inorganic filler and an organic filler. The composition according to Claim 10, wherein said styrenic copolymer has syndiotactic configuration. A multi-layer material which comprises at least one layer containing a styrenic graft copolymer produced by graft polymerizing an ethylenically unsaturated monomer onto a copolymer of a styrenic monomer and a styrenic monomer having a hydrocarbon radical with an unsaturated bond. The multi-layer material according to Claim 12, wherein said styrenic copolymer has syndiotactic configuration. The multi-layer material according to Claim 12 or 13, comprising at least one layer containing said styrenic graft copolymer and a layer composed of at least one material selected from the group consisting of resin, metal, ceramics, glass, paper, fiber, textile and wood. A styrenic copolymer having syndiotactic configuration which comprises a styrenic monomer and a styrenic monomer having a hydrocarbon radical with an unsaturated bond, wherein the double bond of the hydrocarbon radical with an unsaturated bond remains unsaturated. | IDEMITSU KOSAN CO; IDEMITSU KOSAN COMPANY LIMITED | MACHIDA SHUJI; TANI NORIYUKI; TAZAKI TOSHINORI; MACHIDA, SHUJI; TANI, NORIYUKI; TAZAKI, TOSHINORI; Machida, Shuji, c/o Idemitsu Kosan Co.,Ltd.; Tani, Noriyuki, c/o Idemitsu Kosan Co.,Ltd.; Tazaki, Toshinori, c/o Idemitsu Kosan Co.,Ltd. |
EP-0490274-B1 | 490,274 | EP | B1 | EN | 19,970,319 | 1,992 | 20,100,220 | new | H01S3 | G01J9, H01S3 | H01S3, H01S5, G01R23, H03L7, G01J9 | H01S 5/065, H01S 5/00D | Optical pulse oscillator and light frequency measuring apparatus using the same | A microwave active element (2) is connected in series to a drive circuit of a laser light emitting element (1) and the laser light emitting element is caused to operate as a microwave resonator as viewed from the microwave active element. Laser light from the laser light emitting element is delayed by a delay controller (6) and fed back to the laser light emitting element to control its delay time, thereby controlling the microwave resonance frequency. At the resonance frequency the microwave active element oscillates pulses and provides a microwave signal to its output terminal. The laser light emitting element is driven by a current flowing across the microwave active element and repeatedly emits, at its pulse oscillation frequency, laser light pulses of spectral frequencies which bear higher harmonic relation to the self-oscillation frequency of the microwave active element. By frequency sweeping the resonance frequency of the microwave resonator, the frequency (N·F₀) of the laser light can be frequency swept. With the use of the frequency-swept laser light, it is possible to obtain a light frequency measuring apparatus for measuring the frequency of light to be measured. | BACKGROUND OF THE INVENTIONThe present invention relates to an optical pulse oscillator which is capable of simultaneously generating, in addition to the fundamental wave in the microwave band, higher harmonics ranging from millimetric to light waves and is suitable for use in constructing a light frequency measuring apparatus, for example. The invention also pertains to the light frequency measuring apparatus using the optical pulse oscillator. If an electric signal of a frequency related to, for example, the frequency of laser light to be emitted from a laser light source is available from a laser driver, the frequency of light can be determined through utilization of the frequency of the electric signal, besides the frequency of light to be measured can be measured, based on the laser light. Moreover, if the frequency of laser light from the laser light source can be controlled electrically, it is of great utility in practice, because it permits the production of light of a desired frequency. In view of the above, it is considered to obtain the frequency of a light wave by, for instance, frequency-multiplying microwaves from a microwave generator by use of a frequency multiplier. In this case, however, higher harmonics obtainable by the frequency multiplication of microwaves are limited to higher harmonics in the millimetric wave band at the highest and no higher harmonics corresponding to frequencies of light waves are obtainable. Thus, it is impossible, with the prior art, to obtain an electric signal of a frequency related to that of laser light and electrically control the frequency of laser light from the laser light source through mere frequency multiplication of microwaves. US-A-4,734,910 discloses a self mode-locked semiconductor laser diode which operates in an extended optical cavity in conjunction with a negative resistance device for sustained mode-locked operation. Light from the laser diode is put out via an extended resonator. The laser diode is connected via a choke 17 to a DC current source and further connected via the series circuit of a capacitor, a delay line and the negative resistance device to a bias and trigger generator. The delay time by the delay line has to be adjusted such that the total delay time of said series circuit equals the round trip time of the laser light in the optical cavity. US-A-4,464,759 discloses a semiconductor diode laser system with microwave mode locking. The system includes a semiconductor laser diode and an external reflector positioned to receive radiation that emits from the diode and reflects the same back into the diode. The external reflector is positioned so as to return the radiation to the diode at a return time equal to the period of the drive signal for the diode or a submultiple thereof. US-A-3,641,459 discloses apparatus and method for narrowing the pulse width and stabilizing the repetition rate in semiconductor lasers exhibiting self-induced pulsing. In one embodiment the apparatus includes a laser diode connected via a choke to a DC current source. The output light from the laser diode is split by a beam splitter into useful output light and control light. The control light is converted by a photodiode into an electrical signal which is fed back via a microwave amplifier to the node between the choke and the laser diode. Another embodiment of this prior art uses optical feedback. The laser diode is DC driven and the control light from the beam splitter is reflected by a mirror back to the laser diode. SUMMARY OF THE INVENTIONIt is therefore an object of the present invention to provide an optical pulse oscillator capable of simultaneously generating not only the fundamental wave in the microwave band but also higher harmonics ranging from millimetric to light waves and a light frequency measuring apparatus employing such an optical pulse oscillator. According to a first aspect of the present invention as defined in claim 1, the optical pulse generator is made up of a laser light emitting element for emitting multimode laser light, delay control means for feeding the laser lignt back to the laser light emitting element after delaying it for a predetermined time, a microwave active element connected in series to a drive current path of the laser light emitting element and having a negative resistance characteristic in the series-connected portion, an electrical output terminal for extracting therethrough a change in the current flowing through the microwave active element and a light emitting portion for emitting therethrough laser light from the laser light emitting element. With the arrangement according to the first aspect of the invention, the microwave active element forms a microwave oscillator and the laser light source is supplied with its drive current of the microwave band in which the microwave oscillator oscillates. The laser light source emits laser light of a frequency which bears a harmonic relationship to the oscillation frequency of the microwave oscillator. Consequently, the frequency of laser light from the laser light source can be detected by measuring the frequency of the oscillation signal of the microwave oscillator. Since the frequency of laser light can thus be made preknown, the optical pulse oscillator is suitable for use in measuring the frequency of light. According to an embodiment of the present invention, in the above optical oscillator an input terminal is provided in association with the microwave active element and a sample-hold circuit is connected to the electrical output terminal provided for extracting a change in the current flowing through the microwave active element. With the arrangement according to this embodiment of the invention, a signal corresponding to a phase difference between the frequency of an external reference signal and the oscillation frequency of the microwave active element can be obtained from the sample-hold circuit by applying a signal of a known frequency to the input terminal of the microwave active element. The signal corresponding to the phase difference has a frequency equal to the difference between the reference signal and the self-oscillation signal. By measuring this frequency difference, the oscillation frequency of the microwave active element can be known. Further, the frequency of laser light can also be known from the oscillation frequency of the microwave active element. The frequency of the output signal from the sample-hold circuit is the above-said frequency difference and hence is the lower frequency. Hence, the waveform of the output signal can be observed on an oscillograph or similar simple measuring instrument and its frequency can also be measured relatively easily. According to another embodiment of the present invention, in the optical pulse oscillator provided with the sample-hold circuit as mentioned above, the laser light emitting element includes delay control means, which is supplied with the output signal corresponding to the above-mentioned phase difference from the sample-hold circuit to thereby control the delay time of the delay control means. With the arrangement according to this embodiment of the invention, it is possible to change the frequency of laser light which is emitted by the laser light emitting element, through control of the delay time of its delay control means by the signal of the frequency difference. As the frequency of the laser light varies, the oscillation frequency of the microwave active element also varies and eventually becomes equal to the frequency of the external reference signal and the microwave active element performs synchronous oscillation at that frequency. Thus, laser light of a desired frequency can be emitted by a suitable selection of the frequency of the reference signal which is applied to the microwave active element, besides the frequency of the laser light can be frequency-swept. According to a second aspect of the present invention which is defined in claim 4, an optical pulse oscillator whose resonance frequency is controlable is provided with a frequency sweep control circuit, by which the self-oscillation frequency of the optical pulse oscillator and the spectrum of the laser light are frequency swept. The laser light and light to be measured are coupled together by an optical coupler and the coupled light is transduced by an opto-electro transducer into an electric signal. By this, zero beat between a plurality of spectra of the laser light and the light to be measured occurs upon each occurrence of the coincidence between frequency of the light to be measured and the frequency of the swept spectrum. Hence, the frequency of the light to be measured can be detected, based on the number of times of the occurrence of zero beat and the oscillation frequency of the optical pulse oscillator at each of the frequency sweep start and stop points. BRIEF DESCRIPTION OF THE DRAWINGSFig. 1 is a schematic diagram illustrating an embodiment of the optical pulse oscillator according to the first aspect of the present invention; Fig. 2 is an oscillation waveform diagram for explaining the operation of the optical pulse oscillator depicted in Fig. 1; Fig. 3 is a schematic diagram showing a microwave oscillation spectrum, for explaining the operation of the optical pulse oscillator depicted in Fig. 1; Fig. 4 is a schematic diagram showing a laser light spectrum, for explaining the operation of the optical pulse oscillator depicted in Fig. 1; Fig. 5 is a schematic diagram illustrating an embodiment of the optical pulse oscillator of the present invention; Fig. 6A is a waveform diagram of a reference signal which is applied to the optical pulse oscillator shown in Fig. 5, Fig. 6B is a waveform diagram of a microwave oscillation signal available from a microwave active element in Fig. 5; Fig. 6C is a waveform diagram of a signal which is obtained by sampling-holding the output of the microwave active element in Fig. 5; Fig. 7 is a schematic diagram illustrating another embodiment of the optical pulse oscillator of the present invention; Fig. 8 is a schematic diagram illustrating an embodiment of the light frequency measuring apparatus according to the second aspect of the present invention which employs the optical pulse oscillator; Fig. 9 is a graph for explaining an oscillation frequency sweep and the detection of zero beat in the light frequency measuring apparatus shown in Fig. 8; Fig. 10A is a graph showing the relationship between the laser light spectrum and the frequency of the light to be measured, prior to the frequency sweep in the light frequency measuring apparatus depicted in Fig. 8; Fig. 10B is a graph showing the relationship between the laser light spectrum and the frequency of the light to be measured after the frequency sweep in the light frequency measuring apparatus depicted in Fig. 8; Fig. 11 is a block diagram illustrating an other embodiment of the light frequency measuring apparatus according to the second aspect of the present invention; and Fig. 12 is a block diagram illustrating an other embodiment of the light frequency measuring apparatus according to the second aspect of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTSFig. 1 illustrates an embodiment of the optical pulse oscillator according to the first aspect of the present invention. Reference numeral 1 indicates a laser light emitting element, which emits multimode laser light containing a plurality of spectra S1, S2, S3, S4, ... as shown in Fig. 4. This embodiment employs, as the laser light emitting element 1, a semiconductor laser light emitting element including an external resonator. Reference numeral 2 denotes a microwave active element, which is connected into a drive current path to the laser light emitting element in series therewith. The laser light emitting element 1 has its one electrode 1A connected to a common potential point 3 and has the other electrode 1B connected to a negative power supply -V via the microwave active element 2 and a resistor 4. An output terminal 5 is connected to the junction of the microwave active element 2 and the resistor 4. In this embodiment the microwave active element 2 is shown to be a field effect transistor, which has its gate connected to the common potential point 3. The laser light emitting element 1 has a light emitting part 1C, to which a delay controller 6 is optically coupled. The delay controller 6 operates as an external resonator capable of controlling a resonance frequency of a microwave resonator comprising the laser light emitting element 1 and the delay controller 6 and can be formed by a condenser lens 6A, a reflector 6B, a driver 6C for shifting the reflector 6B and a control power supply 6D for controlling the driver 6C. The delay controller 6 in this embodiment is shown to have an arrangement in which the optical path length L between the light emitting part 1C of the laser light emitting element 1 and the reflector 6B of the delay controller 6 is varied by shifting the reflector 6B through control of the voltage V0 of the control power supply 6D to vary the time τ of propagation of light back and forth over the optical path, thereby permitting control of the resonance frequency of the microwave resonator. For example, a piezoelectric element can be used as the driver 6C. The optical path length L may also be varied by use of a structure in which the reflector 6B and the laser light emitting element 1 are mounted on a common substrate not shown and the substrate temperature is controlled by a Peltier element. With the arrangement shown in Fig. 1, letting the time for light to propagate back and forth over the optical path L be represented by τ, the laser light emitting element 1, as viewed from the microwave active element 2, operates as a microwave resonator of a resonance frequency F0 = 1/τ. The microwave active element 2, as viewed from the laser light emitting element 1, shows a negative resistance characteristic in the vicinity of the frequency F0. Consequently, the microwave active element 2 oscillates at the frequency F0 and the laser light emitted from the laser light emitting element 1 is locked in a state in which respective spectra S1, S2, S3, S4, ... are spaced the frequency F0 apart as shown in Fig. 4. This state will hereinafter called a state in which the laser light is mode-locked at the frequency F0. Fig. 2 shows an example of the waveform of an oscillation signal SF which is provided to the output terminal 5. The oscillation signal SF is a pulse-like current of a period 1/F0 and contains higher harmonics F1, F2, F3, F4, ... with the frequency F0 as the fundamental wave, as shown in Fig. 3. The curve G1 in Fig. 3 indicates the gain characteristics of the microwave active element 2. The laser light emitting element 1 is driven by the pulse-like current flowing across the microwave active element 2 and emits light of a frequency N · F0 pulse-wise with a repetitive frequency F0, and the spectra of the light are mode-locked at the frequency F0. In the above, N is the wave number of each spectral component present in the optical path L. Assuming, for example, that the laser light emitting element 1 is one that is able to emit light of wavelengths ranging from 1.5 to 1.6 µm (200 to 187.4 THz in frequency) and that the oscillation frequency F0 of the microwave active element 2 is 10 GHz, the laser light emitting element 1 is capable of generating spectra spaced 10 GHz apart over the frequency range from 187.5 to 200 THz, and the value which the wave number N corresponding to each of such spectra is an integer within the range of between 1.875 × 104 and 2 × 104. Fig. 4 shows the mode-locked spectra of the laser light. That is, the spectra S1, S2, S3, S4, ... of the laser light are arranged at regular intervals of the frequency F0. In Fig. 4 the broken line G2 indicates the gain characteristic of the laser light emitting element 1. The oscillation frequency F0 of the microwave active element 2 and the light emitting frequency of the laser light emitting element 1 can be controlled by changing the voltage V0 of the control power supply 6D. In other words, by changing the voltage V0 of the control power supply 6D, the position of the reflector 6C is changed relative to the light emitting part 1C of the laser light emitting element 1, by which the optical path length L is varied. As the result of this, the time τ for light to travel back and forth between the reflector 6B and the laser light emitting element 1 changes accordingly, and hence the resonance frequency of the microwave resonator formed by the laser light emitting element 1 and the delay controller 6, as viewed from the microwave active element 2, changes and the oscillation frequency F0 of the microactive element 2 changes correspondingly. By continuously changing the oscillation frequency F0 of the microwave active element 2, the light emitting frequency N · F0 of the laser light emitting element 1 can be varied continuously. Thus, the optical pulse oscillator of the present invention provides the microwave signal at the electrical output terminal 5 and, further, permits simultaneous emission of laser light of frequencies bearing the higher harmonic relationship to the microwave. In addition, the frequency F0 of the microwave and the frequency N · F0 of the laser light can arbitrarily be changed by controlling the voltage V0 of the control power supply 6D. Hence, it is possible for the laser light emitting element 1 to emit light of a desired frequency within the wavelength range over which the laser light emitting element 1 is able to emit light. Fig. 5 illustrates an embodiment of the optical pulse oscillator of the present invention. According to this embodiment of the invention, a control terminal of the microwave active element 2 in Fig. 1 is provided, that is, an input terminal 7 is connected to its gate, and a sample-hold circuit 8 is connected to the electrical output terminal 5 and a sample-hold signal is extracted from an output terminal 9 of the sample-hold circuit 8. To the input terminal 7 is applied a reference signal Rf which has a frequency FR close to the oscillation frequency F0 of the microwave active element 2 as depicted in Fig. 6A. The sample-hold circuit 8 in this embodiment is shown to be formed by a diode 8A and a capacitor 8B. By holding the peak value of the oscillation signal SF in the capacitor 8B by means of the diode 8A, a signal SL shown in Fig. 6C is provided at the output terminal 9. The height of each peak of the signal SF corresponds to the phase difference of the pulse relative to the reference signal Rf, and consequently, the level of the signal SL which is obtained while retaining such peaks varies corresponding to the phase difference between the reference signal Rf and the self-oscillation signal SF and the frequency FL of the signal SL is FL = F0 - FR. With the provision of the input terminal 7 and the sample-hold circuit 8 which are connected to the microwave active element 2 and the electrical output terminal 5, respectively, it is possible to obtain at the output terminal 9 of the sample-hold circuit 8 the signal SL of the frequency FL which is equal to the difference between the frequency FR of the reference signal Rf applied to the input terminal 7 and the self-oscillation frequency F0 of the microwave active element 2. Hence, if the frequency FR of the reference signal Rf is preknown, then the self-oscillation frequency F0 of the microwave active element 2 can be detected by measuring the frequency FL of the signal SL. Moreover, once the self-oscillation frequency F0 of the microwave active element 2 is thus known, the frequency N · F0 of the laser light which is emitted from the laser light emitting element 1 can be obtained. As described above, according to the second aspect of the invention, it is possible to obtain the signal SL of a frequency lower than the self-oscillation frequency F0 of the microwave active element 2, in addition to the operational effect obtainable according to the first aspect of the invention, and by measuring the frequency FL of the signal SL, the self-oscillation frequency F0 of the microwave active element 2 and the frequency N · F0 of the laser light from the laser light emitting element 1 can be detected. Thus, this embodiment of the present invention offers the advantage of permitting the detection of the frequency of laser light without using a measuring instrument therefor. Fig. 7 illustrates another embodiment of the optical pulse oscillator of the present invention, which has its feature in that a feedback circuit 11 is provided for feeding back the output of the sample-hold circuit 8 to the delay controller 6 in Fig. 5. The feedback circuit 11 can be formed by a deviation amplifier 11A. The output voltage of the sample-hold circuit 8 is compared with a reference voltage VR and the deviation voltage detected is amplified by the deviation amplifier 11A, the amplified output voltage of which is applied to the driving element 6C of the delay controller 6. At the same time, the reference signal Rf is applied to the input terminal 7 of the microwave active element 2, by which the signal SL (Fig. 6C) corresponding to the phase difference between the reference signal Rf and the self-oscillation signal SF is obtained at the output of the sample-hold 8. The signal SL is compared with the reference voltage VR in the deviation amplifier 11A and the resulting deviation signal ΔSL is applied to the driving element 6C. The driving element 6C shifts the reflector 6B in accordance with the deviation signal ΔSL, thereby controlling the optical path length L. By the control of the optical path length L the time τ for light to go back and forth between the reflector 6B and the laser light emitting element 1 is controlled, and consequently, the resonance frequency of the microwave resonator viewed from the microwave active element 2 is controlled. By the control of the resonance frequency the self-oscillation frequency F0 of the microwave active element2 is controlled and the signal SL is controlled to become equal to the reference voltage VR. When the signal SL is equal to the reference voltage VR, the frequency FR of the reference signal Rf and the frequency F0 of the self-oscillation signal SF stably remain equal to each other. Thus, according to this embodiment of the invention, the self-oscillation frequency F0 of the microwave active element 2 can be brought into coincidence with the frequency FR of the external reference signal Rf. Hence, the self-oscillation frequency F0 of the microwave active element 2 can be controlled from the outside by freely setting the frequency FR of the reference signal Rf. In consequence, the light emitting frequency N · F0 of the laser light emitting element 1 can freely be set in the wavelength region over which the element 1 is capable of emitting light. The variation in the oscillation frequency F0 by temperature changes in the laser light emitting element 1, the microwave active element 2 and the driving element 6C is totally compensated for by the feedback circuit 11, and consequently, the oscillation frequency F0 can be held equal to the frequency FR. Fig. 8 illustrates an embodiment of the light frequency measuring apparatus employing the optical pulse oscillator according to the second aspect of the present invention. According to the second aspect of the invention, the optical pulse oscillator described previously with respect to the first aspect of the invention is utilized to form an apparatus for measuring the frequency of coherent light. In Fig. 8 reference numeral 12 denotes the above-described optical pulse oscillator, which is made up of the laser light emitting element 1, the microwave active element 2, the delay controller 6 associated with the laser light emitting element 1 and the electrical output terminal 5 for detecting a change in the current flowing across the microwave active element 2 as referred to above. In this embodiment the field effect transistor forming the microwave active element 2 has its gate connected to the common potential point 3 as in the optical pulse oscillator proposed according to the first aspect. According to this embodiment of the second aspect of the present invention, a frequency counter 13 is connected to the electrical output terminal 5, for measuring the oscillation frequency F0 of the microwave active element 2, and the delay controller 6 is supplied with a saw-tooth ramp voltage Vsw from a frequency sweep control circuit 14. By applying the ramp voltage Vsw to the driving element 6C of the delay controller 6, the reflector 6B is shifted at a constant speed. As the reflector 6B moves, for example, toward the laser light emitting element 1 at the constant speed, the resonance frequency of the microwave resonator formed by the laser light emitting element 1 and the delay controller 6 rises, and by this change of the resonance frequency, the oscillation frequency F0 of the microwave active element 2 is frequency swept in a direction in which it linearly rises as shown in Fig. 9. By the frequency sweep of the oscillation frequency F0 of the microwave active element 2, the frequency N · F0 of the spectrum of the laser light which is emitted from the laser light emitting element 1 is also frequency swept. The laser light emitted from the laser light emitting element 1 is provided to a coupler 15. Coherent light to be measured Px is also provided to the coupler 15. Let the frequency of the light Px be represented by Fx. The laser light from the laser light emitting element 1 and the coherent light Px are coupled together by the coupler 15. The coupled light is input into an optoelectro transducer 16, by which it is transduced into an electric signal. The electric signal thus transduced by the transducer 16 is output therefrom as a signal which has frequency components of the differences between the frequency N · F0 of respective spectral components of the laser light and the frequency Fx of the coherent light Px, i.e. beat frequency components of the said differences. In this embodiment there is provided a low-pass filter 17 whose cutoff frequency is, for example, lower than the half (F0/2) of the spectral spacing F0 of the laser light (see Fig. 4) by which is extracted that one of the difference frequency components which is, for example, the frequency component of the difference between the frequency Fx of the light Px and the laser light spectrum closest thereto. The difference beat frequency component output from the low-pass filter 17 is provided to a zero beat counter circuit 19. The zero beat counter circuit 19 comprises, for instance, a low-pass filter 19A which detects that the beat frequency has approached zero, a detector 19B which rectifies and smoothens the output signal of the low-pass filter 19A into a pulse signal (see Fig. 9B), and a zero beat counter 19C which counts output pulse signals of the detector 19B to count the number of times of coincidence between the laser light spectrum which is frequency swept and the frequency Fx of the light Px. By the frequency sweep of the frequency of the laser light, the spectra S1, S2, S3, S4, ... shown in Fig. 4 move in one direction and sequentially pass the frequency Fx of the light Px. Consequently, the output signal frequency of the low-pass filter 17 lowers as the spectra approach the frequency Fx and rises as the spectra depart from the frequency Fx, and when the output signal frequency has become substantially equal to the frequency Fx, the zero beat occurs. The low-pass filter 19A has a cutoff frequency (1 kHz, for example) in the vicinity of zero beat and yields a low-frequency signal when each spectrum passes the frequency Fx of the light Px. The low-frequency signal is rectified and smoothed by the detector 19B into a pulse signal. That is, upon each occurrence of the co-incidence between each of the spectra S1, S2, S3, ... being frequency swept and the frequency Fx, such a pulse as shown in Fig. 9B is produced as a signal indicating the zero-beat state. The zero-beat state signal is counted by the zero beat counter 19C. The zero beat number n counted by the zero beat counter circuit 19 is provided to the frequency sweep control circuit 14. The frequency control circuit 14 starts the sweep of the ramp voltage Vsw and, upon detection of an increment in count immediately after the sweep frequency F0 has reached a predetermined frequency F00, stops the sweep and resets the zero beat counter 19C, and the oscillation frequency F01 measured by the frequency counter 13 during this suspension of the sweep is fetched into a calculation circuit 21. Thereafter, the frequency sweep is resumed and when the count value n of the zero beat counter circuit 19 has reached a preset number of times, for example, 100 times, the sweep of the ramp voltage Vsw is stopped and the oscillation frequency F02 at that time is fetched into the calculation circuit 21. Figs. 10A and 10B show the relationships between the laser light spectra (indicated by the solid-lined vertical arrows S) and the frequency (indicated by the solid-lined arrow Fx) of the light to be measured Px at the time point when F0 = F00 (which time point will hereinafter be referred to as the frequency sweep start point) and at the frequency sweep stop point, respectively. The suffix numbers of the reference characters S0, S1, S2, ..., of the laser light spectra in Fig. 10A and 10B are attached to them in the order in which the spectra become equal to the frequency Fx of the light Px as they are swept in a direction in which the spectral frequency rises, and the order is opposite to that shown in Fig. 4. Based on the measured values F01 and F02 and the zero beat count value n, the frequency Fx of the light to be measured Px can be obtained. Since the oscillation frequencies F01 and F02 at the sweep start point and the sweep stop point are both in the zero-beat state, the relationships between the frequency Fx of the light to be measured Px and the measured values F01 and F02 are given by the following equations: Fx = N · F01Fx = (N - n) · F02 where N is a number equal to the order of higher harmonics when the oscillation frequency F0 is used as the fundamental wave. From Eqs. (1) and (2) the following equation can be obtained: N = [n · F02/(F02 - F01)] Letting X be an arbitrary number, Eq. [X] represents an integer which is the closest to the X. By calculating N based on Eq. (3), the true value of N can be determined and the frequency Fx can be calculated by Eq. (2) using the value of N. The frequency Fx thus calculated is displayed on a display 22 shown in Fig. 8. Fig. 11 illustrates another embodiment of the light frequency measuring apparatus according to the second aspect of the present invention. The light frequency measuring apparatus of this embodiment utilizes the optical pulse oscillator proposed according to the second and third aspects of the invention. That is, the input terminal 7 is connected to the gate of the microwave active element 2 and the reference signal Rf is applied to the input terminal 7 from a reference signal source 24. The reference signal source 24 can be formed by a voltage-controlled oscillator, for instance. The ramp voltage Vsw is applied from the frequency sweep control circuit 14 to the reference signal source 24 formed by the voltage-controlled oscillator, and the frequency FR of the reference signal Rf from the reference signal source is subjected to the frequency sweep from the frequency F01 to F02 (see Fig. 9A). The sample-hold circuit 8 is connected to the output side of the microwave active element 2 and the output at the output terminal 9 of the sample-hold circuit 8 is provided via the feedback circuit 11 to the driving element 6C of the delay controller 6. A closed loop is formed by the connection of the feedback circuit 11 and the oscillation frequency F0 of the microwave active element 2 frequency sweeps following the oscillation frequency F01 to F02 of the reference signal source 24. By the frequency sweep of the oscillation frequency F0 of the microwave active element 2 from F01 to F02, the spectral frequency of the laser light from the laser light emitting element 1 is also subjected to a frequency sweep in the direction W shown in Fig. 10A. The frequency-swept laser light and the light to be measured Px are coupled together by the coupler 15. The coupled light is transduced bv the opto-electro transducer 16 into an electric signal, which is applied to the zero beat counter circuit 19 to count the zero beat number n during the frequency sweep period. The zero beat count value n and the frequency measured values F01 and F02 available from the frequency counter 13 are utilized to obtain, by Eq. (3), N for determining the spectral frequency N · F0 of the laser light and the N is used to calculate the frequency Fx of the light Px by Eq. (2) as in the case of the first embodiment of the first aspect of the invention, and the frequency Fx is displayed on the display 22. By the way, it is impossible, in the embodiments of Figs. 8 and 11, to detect the oscillation frequency F0 of the microwave active element 2 exactly at the time of detection of the zero beat, because there is a time lag in actually stopping the sweep of the oscillation frequency F0 of the microwave active element 2 in consequence of stoppage of the sweep of the ramp voltage by the frequency sweep control circuit 14 after the detection of the zero beat by the zero beat counter circuit 19. Further, the zero beat counter 19C counts, as a zero beat detection signal, the pulse-like signal which is yielded from the low-pass filter 19A when a difference beat frequency Fif, which is the output signal frequency of the low-pass filter 17, becomes lower than the cutoff frequency of the low-pass filter 19A. Hence, the zero beat detection signal has a pulse width corresponding to the pass bandwidth of the low-pass filter 19A. This means that it is impossible to detect the exact time point of the zero-beat state in which one of the sweep spectra of the laser light and the frequency Fx of the light to be measured Px completely coincide with each other and the zero beat frequency Fif is reduced to zero. It is therefore impossible to determine the oscillation frequency F02 exactly at the time of occurrence of the zero beat. Moreover, the frequency Fx of the light Px may vary in the time interval between the detection of the zero beat and the start of measurement of the oscillation frequencies F01 and F02. However, the frequency Fx of the light to be measured Px can be determined with high precision by stopping the frequency sweep at a time point different from that of the occurrence of the zero beat and then measuring the difference beat frequency Fif at the sweep stopping time, as described below in conjunction with another embodiment of the light frequency measuring apparatus according to the second aspect of the present invention. The apparatus according to this embodiment of the second aspect of the invention employs a frequency counter 18 for measuring the beat frequency Fif of the output difference beat signal of the low-pass filter 17 as indicated by the broken line in Fig. 8 or 11. When the zero-beat counter 19C has counted the occurrence of zero beat a predetermined number of times n, the frequency sweep control circuit 14 stops the frequency sweep to measure the oscillation frequency F02 and then resumes the frequency sweep for an additional frequency ΔF which is smaller than the microwave oscillation frequency width F0/2 (N - n) which corresponds to the half of the spectrum spacing of the laser light, and thereafter stops the frequency sweep followed by measurement of the oscillation frequency F03. That is, the value of ΔF is chosen such that the difference beat frequency Fif at the sweep stopping time becomes lower than the half, F0/2, of the spectrum spacing of the laser light. Incidentally, the oscillation frequency F0 is swept substantially from the frequency F00 to F03 and since the sweep width is sufficiently small as compared with the oscillation frequencies F00 and F03, the oscillation frequency F0 can be selected to be an arbitrary value within the oscillation frequency sweep range. Further, since N - n holds in general, the value ΔF needs only to be selected smaller than F0/2N. As the result of this, the spectra of the laser light also shift by the difference frequency Fif as indicated by the broken lines in Fig. 108 and the shift amount Fif can be obtained by measuring the output signal frequency of the low-pass filter 17 as the difference beat frequency. As is evident from Fig. 10B, the frequency Fx of the light to be measured Px is given by the following equation: Fx = (N - n) · F03 - Fif The oscillation frequency F03 of the microwave active element 2 at the time when the oscillation frequency F0 has been shifted by ΔF from the oscillation frequency F02 (the zero-beat state) is measured by the frequency counter 13, and at the same time, the difference beat frequency Fif which is the output signal frequency of the low-pass filter 17 is measured by the frequency counter 18. By substituting into Eq. (4) these measured values and the N obtained by Eq. (3), the frequency Fx of the light Px can be calculated. Since the calculation of Eq. (4) does not involve the values of the frequencies F01 and F02 which are measured after the detection of zero beat, the value of the oscillation frequency Fx can be determined with high accuracy. A brief description will be given of the reason for which the value of the above-mentioned ΔF is selected smaller than F0/2N. The relationship between ΔF and Fif is expressed by the following equation: Fif = (F03 - F02 )×(N -n) = ΔF (N -n) Assuming that the frequency Fx of the light to be measured Px lies between the spectra Sn and Sn+1 indicated by the broken lines in Fig. 10B, there is the possibilities that the difference beat frequency Fif of the same value is obtained as the difference between the frequency Fx and the frequency F03(N - N) of the broken-lined spectrum Sn and between the frequency Fx and the frequency F03 (N - n - 1) of the broken-lined spectrum Sn+1, but in the latter case the count value n and the spectrum Sn+1 do not correspond to each other, resulting in a erroneous measurement. To avoid this, it is necessary to extract only the difference beat frequency Fif between the frequency Fx and the broken-lined spectrum Sn of the same order as that of the solid-lined spectrum Sn which caused the zero beat detected immediately before the stoppage of the frequency sweep. To this end, it is necessary to stop the sweep within the range in which the frequency Fif will not exceed F02/2, after counting the zero beat number n. Accordingly, ΔF needs only to be selected to satisfy ΔF < F02/2(N - n). Since the following equation holds: F02/2(N - n) > F02/2N > F00/2N, ΔF needs only to be selected smaller than F00/2N. In the case where N and n are selected to be about 2 × 104 and 100 or so, respectively, as referred to previously, it will suffice to select F0 to be an arbitrary value within the sweep frequency region and ΔF to be smaller than F0/2N. More preferably, ΔF is chosen as given by the following equation so as to allow variations in the frequency Fx of the light Px as much as possible. ΔF = F02/4(N - n)≃F00/4N Also in this case, if N and n are chosen as mentioned above, then ΔF can be selected to be F0/4N relative to the arbitrarily determined frequency F0 in the sweep frequency region. In the embodiment which performs the additional sweep of the frequency ΔF, when the zero beat number n has been reached, the frequency sweep is stopped and the oscillation frequency F02 is measured and then the frequency sweep is performed additionally by ΔF, but the frequency sweep need not be stopped when the zero beat count reaches n and, instead, the additional sweep of the frequency ΔF may continually follow. In such an instance, the frequency F02 is not measured and the value N is determined by the following equation derivable from Eqs. (1) and (4) and then the frequency Fx is calculated by substituting the value of N and the frequencies Fif and F03 into Eq. (4). N = [(Fif + nF03)/(F03 - F01)] While in the embodiments of Figs. 8 and 11 the oscillation frequency F0, i.e. the frequencies F01, F02 and F03 are measured by measuring the microwave oscillation signal from the output terminal 5 of the microwave active element 2 by use of the frequency counter 13, it is also possible to adopt an arrangement in which a band-pass filter 23 having a center frequency F0 is connected to the output of the opto-electro transducer 16 as indicated by the broken lines in Figs. 8 and 11, the signal component of the oscillation frequency F0 is extracted by the band-pass filter 23 and the frequency F0 is measured by the frequency counter 13. Fig. 12 illustrates in block form another embodiment of the light frequency measuring apparatus according to the second aspect of the present invention, which is a modified form of the apparatus shown in Fig. 8. This embodiment employs, in the optical pulse oscillator 12, a CPM (Colliding-Pulse Mode-Locking) laser diode 1 (Chen et al, Appl. Phys. Letters, Vol. 58, No. 12, 1991, pp1253-1255). The CPM laser diode is supplied with proper bias voltages Vb and Vc to emit pulsed light mode-locked at a resonance frequency dependent on the optical waveguide length L. In this embodiment a modulating electrode 6E is formed on a portion forming part of the resonator of the CPM laser diode 1 to form the delay controller 6. Since the refractive index of the optical waveguide of the delay controller 6 varies with applied voltage or current, the delay time or laser light which travel back and forth in the optical waveguide of the delay controller 6 is controlled. Accordingly, the pulse oscillation frequency F0 varies and the cavity length L of the laser diode 1 varies equivalently, causing variations in the spectral wavelength of the laser light pulse which is produced. The repetitive frequency F0 of the light pulse is expressed by F0 = C/nL, where n is the refractive index of the optical waveguide and C is the velocity of light in a vacuum. As in the case of the Fig. 8 embodiment, the laser light emitted from the laser diode 1 is coupled with the coherent light Px to be measured, by the coupler 15, and the coupled light is transduced by the opto-electro transducer 16 into an electric signal containing the frequency component of the difference between the laser light and the coherent light Px. The electric signal is applied to the low-pass filter 17 to extract the component of the difference frequency Fif = Fx - N · F0, which is provided to the zero-beat counter circuit 19. The cavity length L of the laser diode 1 is controlled by the ramp voltage (or current) which is produced by the frequency sweep control circuit 14 and the spectrum of the laser light is swept. This embodiment does not use such a microwave active element 2 as used in the Fig. 8 embodiment, because the CPM laser diode 1 generates light pulses of the repetitive frequency F0. Accordingly, in this embodiment the output of the opto-electro transducer 16 is applied to the band-pass filter 23 to extract the component of the frequency F0 and the frequency component thus extracted is measured by the frequency counter 13 to thereby measure the frequencies F01, F02 and F03 in the embodiment of Fig. 8. Since the principles of measuring the wavelength of the light Px are the same as in the case of Fig. 8, no description will be given of the operation therefor. As described above, with the optical pulse oscillator according to the first aspect of the present invention, it is possible to simultaneously obtain the electric signal SF having the self-oscillation frequency F0 of the microwave active element 2 and the laser light of the frequency N · F0 which bears a higher harmonic relation to the self-oscillation frequency F0. Hence, the light emitting frequency of the laser light emitting element 1 can be known by measuring the self-oscillation frequency F0 of the microwave active element 2. Thus, the light emitting frequency of the laser light emitting element 1 can be detected without the necessity of using an expensive light frequency measuring instrument--this allow ease in measuring the frequency of light. The optical pulse oscillator according to the first embodiment of the first aspect of the present invention has the construction in which the sample-hold circuit 8 provides the signal SL having the frequency difference F0 - FR between the frequency FR of the external reference signal Rf and the self-oscillation frequency F0 of the microwave active element 2. Hence, if the frequency FR of the reference signal Rf is preknown, the self-oscillation frequency F0 of the microwave active element 2 can be obtained by measuring the difference frequency F0 - FR. The difference frequency F0 - FR is sufficiently lower than those F0 and FR in the microwave band, and hence can easily be measured. Furthermore, a simple measuring instrument such as an oscillograph can also be used for observing waveforms and measuring frequencies. With the optical pulse oscillation according to the second embodiment of the first aspect of the present invention, the self-oscillation frequency of the microwave active element 2 can be brought into agreement with the frequency of the external reference signal. This offers an advantage that the light emitting frequency of the laser light emitting element 1 can be set arbitrarily in its light-emittable wavelength range by a suitable selection of the frequency of the reference signal. With the light freqency measuring apparatus according to the second aspect of the present invention, the frequency of light can be measured with a high degree of accuracy. The accuracy of a conventional wavemeter using a Michelson inter-ferometer is about 1 pp, but the present invention achieves measurement accuracy substantially in the range of 10-10 10-11. Although the above embodiments have been described to employ a laser diode as the laser light emitting element 1, it is also possible to utilize a solid laser such as a YAG laser, or a gas laser, in addition to the laser diode. Besides, negative resistance elements such as a Gunn diode as well as a field effect transistor may also be used as the microwave active element 2. | An optical pulse oscillator comprising: a laser light emitting element (1) which emits multimode laser light; delay control means (6) optically coupled to said laser light emitting element (1) to form a resonator with said laser light emitting element and controlling an optical path length of the multimode laser light between said laser light emitting element and said delay control means thereby varying the propagation time of the multimode laser light travelling back and forth along the optical path between said laser light emitting element and said delay control means, the multimode laser light emitted from said laser light emitting element propagating back and forth over said optical path as well as being outputted to the outside; a microwave active element (2) inserted into the drive current path to said laser light emitting element in series therewith to form a microwave oscillator with said laser light emitting element, said microwave active element (2) showing a negative resistance characteristic in the vicinity of a microwave resonance frequency determined by said laser light emitting element and said delay control means and oscillating at the resonance frequency; and an electrical output terminal (5) connected to said drive current path to said laser light emitting element for extracting the microwave oscillation signal outputted from said microwave active element. The oscillator of claim 1, further comprising an input terminal (7) for applying therethrough an external signal to said microwave active element (2), and a sample-hold circuit (8) connected to said electrical output terminal (5), for extracting a signal corresponding to the phase difference between the oscillation frequency of said microwave active element and said external signal applied to said input terminal. The oscillator of claim 2, further comprising a feedback circuit (11) for feeding back the output signal of said sample-hold circuit (8) to said delay control means (6) to vary the optical path length of the multimode laser light between said laser light emitting element and said delay control means, thereby making the oscillation frequency of said microwave active element (2) equal to the frequency of said external signal applied to said input terminal (7). A light frequency measuring apparatus comprising: optical pulse oscillator (12) as claimed in any of claims 1 to 3 which has said delay control means (6) for feeding back thereto emitted laser light after delaying it for a desired period of time, oscillates pulses at a resonance frequency defined by the delay time of said delay control means and repeatedly emits, at said pulse oscillation frequency, laser light pulses of spectral frequencies which are integral multiplies of said pulse oscillation frequency; frequency sweep control means (14) which applies a ramp signal to said optical pulse oscillating means to vary said delay time of said delay control means to sweep said pulse oscillation frequency, thereby sweeping said spectral frequencies of said laser light pulses; frequency measuring means (13) for measuring said pulse oscillation frequency at the start and stopping of said frequency sweep by said frequency sweep control means; coupling means (15) for coupling said laser light pulses emitted from said optical pulse oscillating means and light to be measured; opto-electric transducer means (16) whereby the coupled light from said coupling means is transduced into an electric signal; zero-beat counting means (19) for counting how many times a difference beat between the frequency of said light to be measured and said spectral frequencies of said laser light from said optical pulse oscillating means reaches the state of zero beat as said pulse oscillation frequency is swept and for stopping said frequency sweep by said frequency sweep control means after said counting has reached a predetermined count value; and calculating means (21) for calculating said frequency of said light to be measured, based on said pulse oscillation frequencies measured by said frequency measuring means at the start and stopping of the said frequency sweep and said predetermined count value of said counting. The apparatus of claim 4, wherein said optical pulse oscillating means (12) includes a laser light emitting element (1) optically coupled to said delay control means (6), a drive current circuit for driving said laser light emitting element, and a microwave active element (2) connected in series to said drive current circuit, said microwave active element having a negative resistance characteristic in a microwave resonance frequency band determined by said laser light emitting element and said delay control means and oscillating pulses at a frequency within said microwave resonance frequency band. The apparatus of claim 5, wherein said frequency measuring means (13) is connected to one terminal of said microwave active element (2) and measures the pulse oscillation frequency of said microwave active element. The apparatus of claim 5, wherein said frequency measuring means (13,23) a includes band-pass filter (23) of said microwave resonance frequency band connected to the output of said opto-electric transducer means (16) and measures the oscillation frequency of said pulse oscillation frequency component extracted by said band-pass filter from the output signal of said opto-electro transducer means. The apparatus of claim 6 or 7, wherein said frequency sweep control means (14) includes a frequency sweep control circuit which generates and applies said ramp signal to said delay control means (6) to control the delay time of said laser light which is fed back to said laser light emitting element. The apparatus of claim 6 or 7, wherein said frequency sweep control means includes: a frequency sweep control circuit (14) for generating said ramp signal; reference signal generating means (24) for generating a reference signal frequency-swept by said ramp signal and for applying said reference signal to a control terminal of said microwave active element (2); sample-hold means (8) connected to said microwave active element, for generating a signal corresponding to the phase difference between the oscillation signal of said microwave active element and said reference signal; and feedback means which compares the output of said sample-hold means with a reference level and supplies said delay control means (6) with a signal corresponding to the difference between them to control said delay time, thereby causing the pulse oscillation frequency of said microwave active element to agree with the frequency of said reference signal. The apparatus of claim 4, wherein said optical pulse oscillating means (12) includes a pulse mode-locking laser diode (1), a driver for driving said pulse mode-locking laser diode and said delay control means (6) formed as a unitary structure with said pulse mode-locking laser diode, and wherein said frequency measuring means includes a band-pass filter (23) of said microwave resonance frequency band connected to the output of said opto-electric transducer means (16) and measures the oscillation frequency of said pulse oscillation frequency component extracted by said band-pass filter from the output signal of said opto-electro transducer means. The apparatus of claim 4, 5, or 10, further comprising low-pass filter means (17) for extracting said difference beat component from the output of said opto-electric transducer means (16) and beat frequency measuring means for measuring the frequency of said difference beat component, and wherein said frequency sweep control means (14) stops said frequency sweep after additionally performing it by a predetermined frequency when said zero-beat counting means (19) has counted said zero beat by said predetermined value and said calculating means (21) calculates the frequency of said light to be measured, based on said zero-beat count value, said pulse oscillation frequency at the start of said frequency sweep, said pulse oscillation frequency at the end of said additional frequency sweep and said beat frequency at the end of said additional frequency sweep. | ADVANTEST CORP; ADVANTEST CORPORATION | NIKI SHOJI; NIKI, SHOJI |
EP-0490278-B1 | 490,278 | EP | B1 | EN | 19,960,214 | 1,992 | 20,100,220 | new | C08G18 | null | C08G18 | C08G 18/66P2B2, M08G120:00, C08G 18/24K4, C08G 18/24D | Polyurethane rim elastomers obtained with hydroxyl-containing organotin catalysts | The invention relates to reaction injection molded elastomers derived from high molecular weight polyether polyols, an aromatic diamine chain extender, a polyisocyanate and a hydroxyl-containing organotin catalyst. The reaction injection molded (RIM) elastomers of this invention are useful, for example, as automobile body parts. | TECHNICAL FIELDThe present invention relates to reaction injection molded (RIM) elastomers. BACKGROUND OF THE INVENTIONPolyurethane and polyurethaneurea RIM elastomers require the use of tin catalysts for acceptable processing. In a system based on high molecular weight polyether polyols and aromatic diamine chain extenders, it is customary to use dibutyltin dilaurate to catalyze the hydroxyl-isocyanate (OH-NCO) reaction. Without this catalyst additive it is impossible to make a RIM part with sufficient green strength to be demolded. Yet, it is well known that the presence of tin catalyst in the final elastomer limits the thermal stability bf the material since it can catalyze the unzipping of urethane bonds. The need for high thermal stability in RIM elastomers is the result of high paint baking temperatures. Physical distortion, cracking, oiling and blistering can be observed if tin catalyst is present to promote the chemical breakdown of urethane linkages. One solution to this problem has been the use of polyurea RIM based on isocyanate-reactive components which do not contain OH group, e.g., aliphatic amine terminated polyethers as disclosed in U.S. 4,433,067. Since the reaction of the amino (-NH₂) groups with NCO groups is so rapid, no tin catalyst is needed although there is still some benefit to their use in polyurea RIM elastomers as disclosed in U.S. 4,444,910. However, the drawback to this solution is the high reactivity of the aliphatic amine terminated polyethers which makes is difficult to achieve high modulus elastomers with good flowability. Additionally, these products are more expensive than conventional RIM polyols and are not available in filled versions such as polymer polyols, grafted polyols or PHD polyols. EP-A-60974 discloses amino and amido dialkyltin dicarboxylates and stannoxy carboxylates useful as catalysts for promoting reaction of organic isocyanates with organic compounds having one or more active hydrogen-containing groups. SUMMARY OF THE INVENTIONThe present invention is a reaction injected molded (RIM) elastomer comprising the cured reaction product of a polyether polyol of greater than 500 molecular weight, an aromatic diamine chain extender and an aromatic polyisocyanate in the presence of a hydroxyl-containing organotin catalyst, such as, for example, a diorganotin bis(hydroxyl-containing organo) compound. The use of a hydroxyl-containing organotin catalyst provides for improved thermal stability of conventional polyether polyol polyurethane and polyurethaneurea RIM systems. In addition, unfilled or filled polyols can be used and high modulus elastomers with improved flowability over polyurea RIM systems are obtained. DETAILED DESCRIPTION OF THE INVENTIONThe RIM elastomer of the invention may be prepared from as few as four ingredients, namely a high molecular weight polyether polyol, an aromatic diamine chain extender, an aromatic polyisocyanate and a hydroxyl-containing diorganotin catalyst. The polyether polyols useful in the invention include primary and secondary hydroxyl-terminated polyether polyols of greater than 500 average molecular weight having from 2 to 6 functionality, preferably from 2 to 3, and a hydroxyl equivalent weight of from 250 to about 2500. Mixtures of polyether polyols may be used. In a prefered embodiment the polyether polyols have an average molecular weight of at least 6000. The polyether polyols useful in the invention are polyether polyols made from an appropriate initiator to which lower alkylene oxides such as ethylene oxide, propylene oxide, butylene oxide or mixtures thereof are added resulting in hydroxyl-terminated polyols. When two or more oxides are used, they may be present as random mixtures or as blocks of one or the other polyether. Thus the polyalkylene ether polyols include the poly(alkylene oxide) polymers, such as poly(ethylene oxide) and poly(propylene oxide) polymers and copolymers, with terminal hydroxyl groups derived from polyhydric compounds, including diols and triols; for example, among others, ethylene glycol, propylene glycol, 1,3-butane diol, 1,4-butane diol, 1,6-hexane diol, neopentyl glycol, diethylene glycol, dipropylene glycol, pentaerythritol glycerol, diglycerol, trimethylol propane and like low molecular weight polyols. In the practice of this invention, a single high molecular weight polyether polyol may be used. Also, mixtures of high molecular weight polyether polyols such as mixtures of di- and tri-functional materials and/or different molecular weight or different chemical composition materials may be used. The aromatic diamine chain extenders useful in this invention include, for example, 1-methyl-3,5-diethyl-2,4 diaminobenezene; 1-methyl-3,5-diethyl-2-6-diaminobenzene (both of these materials are also called diethyl toluenediamine or DETDA); 1,3,5-triethyl-2,6-diaminobenzene; 2,4-dimethyl-6-t-butyl-3,5-diaminobenzene; 3,5,3',5'-tetraethyl-4,4'-diamino diphenylmethane; 1-methyl-3-t-butyl-2,4-diaminobenzene; 1-methyl-5-t-butyl-2,6-diaminobenzene (both these materials are also called t-butyl toluenediamine or TBTDA) and the like. Particularly preferred aromatic diamine chain extenders are DETDA and TBTDA. It is within the scope of the invention to include some aliphatic chain extender materials as described in U.S. 4,246,363 and 4,269,945. A wide variety of aromatic polyisocyanates may be used. Typical aromatic polyisocyanates include phenylene diisocyanate, toluene diisocyanate and 4,4'-diphenylmethane diisocyanate. Especially suitable are the 2,4- and 2,6-toluene diisocyanates individually or together as their commercially available mixtures. Other especially suitable mixtures of diisocyanates are those known commercially as crude MDI also known as PAPI, which contain about 60% of 4,4'-diphenylmethane diisocyanate along with other isomeric and analogous higher polyisocyanates. Also suitable are prepolymers of these polyisocyanates comprising a partially pre-reacted mixture of polyisocyanates and polyether polyols. The hydroxyl-containing diorganotin compound may suitably be an organotin compound of the following general formula: R₂Sn[X-R¹-OH]₂where Ris a C₁-C₈ alkyl group, preferably n-butyl or octyl, or an aryl group, preferably phenyl; R¹is a C₂-C₂₂ divalent hydrocarbyl group, for example, alkylene, arylene and alkarylene, preferably ethylene, propylene, butylene, phenylene [-C₆H₄-], -CH₂-C₆H₄-, -CH₂CH₂-C₆H₄-, and -CH₂CH₂CH₂C₆H₄-, which hydrocarbyl group may also contain a hydroxyl substituent; and Xis a linking group which may be -S- or -O₂C-. When the linking group X is -S-, it is preferred that R¹ be a hydroxy substituted C₃-C₅ alkylene group such as -CH₂-CH(OH)-CH₂-. When the linking group X is -O₂C-, it is preferred that R¹ be -(CH₂)n-C₆H₄- where n = 0-3. A general procedure for preparing the diorganotin bis-carboxylates and diorganotin bis-mercaptides of the above general formula would involve charging a mixture of diorganotin oxide (R₂SnO), the appropriate carboxylic acid (HOR¹CO₂H) or mercaptan (HOR¹SH), in a solvent such as toluene to a reaction vessel and heating the reaction mixture to reflux temperature until the water of reaction has been removed by distillation. The organic solvent can then be evaporated to afford essentially quantitative product yields of the diorganotin bis-carboxylate or bis-mercaptide. A catalytically effective amount of the diorganotin catalyst is used in a polyether polyol RIM formulation comprising polyisocyanate, aromatic diamine and polyether polyol. Specifically, suitable amounts of a catalyst may range from about 0.025 to 0.3 parts, preferably 0.05 to 0.2 parts, per 100 parts per weight polyol in the RIM elastomer formulation. Other conventional RIM formulation ingredients may be employed as needed, such as, for example, foam stabilizers, also known as silicone oils or emulsifiers. The foam stabilizer may be an organic silane or siloxane. Reinforcing materials, if desired, used in the practice of the invention are known to those skilled in the art. For example, chopped or milled glass fibers, chopped or milled carbon fibers and/or other mineral fibers are useful. Postcuring of the elastomer of the invention is optional and its employment depends on the desired properties of the end product. Postcuring will improve some properties such as heat sag. Example 1Dibutyltin-bis(2,3-dihydroxypropylmercaptide)A mixture of 24.9g (0.10 mole) dibutyltin oxide, 21.6g (0.20 mole) 3-mercapto-1,2-propanediol in 300 ml toluene were mixed and reacted as described in Example 1. Removal of the toluene yielded 44.5g (99.5% yield) of dibutyltin-bis-(2,3-dihydroxypropylmercaptide), a straw-colored viscous liquid. Example 2Dibutyltin-bis[3-(4-hydroxyphenyl)-propionate]Following the procedure of Example 1, 24.9g (0.10 mole) dibutyltin oxide was reacted with 33.2g (0.20 mole) 3-(4-hydroxyphenyl)propionic acid in 300 ml toluene to give 56g of dibutyltin-bis-3-(4-hydroxyphenyl)propionate which was a white crystalline material melting at 48-50°C. Example 3Dibutyltin-bis-[2,2-di(hydroxymethyl)propionate]Following the procedure of Example 1, 24.9g (0.10 mole) dibutyltin oxide was reacted with 26.8g (0.20 mole) 2,2-bis(hydroxymethyl)propionic acid in toluene to give 48g of dibutyltin-bis-2,2-di-(hydroxymethyl)propionate, a white crystalline material melting at 157-161°C. Example 4Dibutyltin-bis(2-hydroxyethylmercaptide)Following the procedure of Example 1, 24.9g (0.10 mole) dibutyltin oxide was reacted with 15.6g (0.20 mole) 2-mercaptoethanol in toluene to give 36g of dibutyltin-bis-(2-hydroxyethylmercaptide), a light yellow liquid. In the following examples, the RIM elastomer runs were conducted using the following materials: Multranol M 3901 - a glycerine-initiated polyoxyalkylene polyether triol having a hydroxyl number of 28 from Mobay Corp. L-5304 - a commercial silicone surfactant from Union Carbide. DC-198 - a commercial silicone surfactant from Air Products and Chemicals, Inc. Mondur PF - 4,4'-diphenyldiisocyanate, which has been liquified by reaction with a low molecular weight glycol to an NCO content of about 22.6% from Mobay Corp. Dabco 33LV - a 33% solution of triethylenediamine in a glycol carrier from Air Products and Chemicals, Inc. DETDA - an 80/20 mixture of 3,5-diethyl-2,4-toluenediamine and 3,5-diethyl-2,6-toluenediamine from Ethyl Corp. t-BTDA - an 80/20 mixture of 5-t-butyl-2,4-toluenediamine and 3-t-butyl-2,6-toluenediamine from Air Products and Chemicals, Inc. T-12 - dibutyltin dilaurate from Air Products and Chemicals, Inc. T-120 - dibutyltin-bis(laurylmercaptide) from Air Products and Chemicals, Inc. UL-28 - dimethyltin dilaurate from Witco Chemical Corp. Reaction injection molding elastomers were prepared using a model SA8-20 laboratory machine (LIM Kuntstoff Technologie GmbH, Kittsee, Austria) suitable for processing 2-component mixtures. 10-30 cc/min metering pumps for component A (modified methylenediphenyldiisocyanate, MDI) and B (polyether polyol plus chain extender, silicone and catalyst) were driven synchronously by sprocket wheels in proportion to the mixture to be processed by means of a variable speed (50-250 rpm) motor. Any desired mixing ratio may be established by changing gears. Components A and B were conveyed into a mixing chamber by individually controlled compressed air actuated valves. A high-speed rotor, continuously adjustable from 10,000 to 18,000 rpm using a frequency transformer, mixed the components. Example 5For Runs A-F flat placque parts (200 x 200 x 2mm with an average weight of 100g) were made according to the formulations in Table 1 and were postcured at 120°C for 1 hour. In each system, the tin metal content was held constant. Thermal stability was determined by annealing the parts for 80 minutes at 165°C, followed by visual and tactile inspection. Both Runs A and B made with non-isocyanate-reactive catalysts (T-12 and T-120) crumbled into pieces as a result of this thermal abuse. RunA B C D E F M-3901100100100100100100 t-BTDA262626262626 L-53040.80.80.8 0.8 0.8 0.8 Dabco-33LV0.1260.1260.1260.1260.1260.126 Tin Catalyst TypeT-12T-120Ex 1Ex 2Ex 3Ex 4 Level0.1260.130.0790.110.950.8 Mondur PF66.766.766.766.766.766.7 Condition After AnnealingCrumblyCrumblyGoodFairFairBrittle Example 6Dibutyltin bis(12-hydroxystearate)A mixture of dibutyltin oxide, 31.2g (0.125 mole), 12-hydroxystearic acid, 75g (0.25 mole) and 250ml toluene was charged to a round-bottom flask (fitted with a stirrer, thermocouple, and condenser with a Dean-Stark water trap) and heated at reflux until all water of reaction was collected in the trap. Removal of the toluene (flash evaporator) yielded 125g (97%) of the desired product, a cream colored brittle solid. Example 7Dibutyltin bis(ricinoleate)Following the procedure described in Example 11, ricinoleic acid, 74.25g (0.25 mole) was reacted with dibutyltin oxide, 31.2g (0.125 mole) in 250ml toluene. Removal of toluene yielded 120g (94%) of the desired product, a yellow viscous liquid. Example 8For Runs G-N flat placque parts (200 x 200 x 2 mm, with an average weight of 100 grams) were made according to the formulations in Table 2 were postcured at 121°C for one hour. In each system the tin metal content was held constant. Thermal stability was judged by the high temperature heat sags. Lower sags indicate increased thermal stability. Those Runs made with isocyanate-reactive catalysts showed lower heat sags than conventionally used T-12, and, in particular, the tin catalyst in Run I was remarkably good. The hydroxyl-containing diorganotin catalysts, being isocyanate-reactive, become part of the polymer matrix and are therefore not sufficiently mobile to promote thermal degradation of urethane-containing elastomers. Surprisingly, these compounds are still able to provide enough catalytic activity to permit the molding of RIM elastomers. STATEMENT OF INDUSTRIAL APPLICATIONThe present invention provides polyether polyol RIM elastomers made using hydroxyl-containing organotin catalysts. | A reaction injection molded elastomer made by reacting in a closed mold a composition comprising polyether polyols greater than 500 average molecular weight, an amine terminated chain extender, an aromatic polyisocyanate and an organotin catalyst of the following general formula R₂Sn[X-R¹-OH]₂where Ris a C₁-C₈ alkyl group or an aryl group, R¹is a C₂-C₂₂ divalent hydrocarbyl group which may also contain a hydroxyl substituent; and Xis a linking group which is -S- or -O₂C-. The elastomer of Claim 1 in which R is butyl or octyl. The elastomer of Claim 1 in which X is -S-. The elastomer of Claim 3 in which R¹ is a hydroxy substituted C₃-C₅ alkylene. The elastomer of Claim 3 in which R¹ is -CH₂-CH(OH)-CH₂-. The elastomer of Claim 1 in which X is -O₂C-. The elastomer of Claim 6 in which R¹ is -(CH₂)n-C₆H₄- where n = 0-3. The elastomer of Claim 7 in which R¹ is -(CH₂)₂-C₆H₄-. The elastomer of Claim 6 in which R¹ is or A reaction injection molded elastomer made by reacting in a closed mold a composition comprising polyether polyols greater than 500 average molecular weight, an amine terminated chain extender, an aromatic polyisocyanate and an organotin catalyst of the formula R₂Sn[S-R¹-OH]₂where Ris butyl or octyl and R¹is a hydroxy substituted C₃-C₅ alkylene. The elastomer of Claim 10 in which R¹ is -CH₂-CH(OH)-CH₂-. The elastomer of Claim 11 in which R is butyl. A reaction injection molded elastomer made by reacting in a closed mold a composition comprising polyether polyols greater than 500 average molecular weight, an amine terminated chain extender, an aromatic polyisocyanate and an organotin catalyst of the formula R₂Sn[O₂C-R¹-OH]₂where Ris butyl or octyl and R¹is a C₂-C₂₂ divalent hydrocarbyl group. The elastomer of Claim 13 in which R¹ is -(CH₂)n-C₆H₄- where n = 0-3. The elastomer of Claim 13 in which R¹ is -CH₂CH₂C₆H₄-. The elastomer of Claim 13 in which R¹ is or | AIR PROD & CHEM; AIR PRODUCTS AND CHEMICALS, INC. | DEWHURST JOHN ELTON; NICHOLS JAMES DUDLEY; DEWHURST, JOHN ELTON; NICHOLS, JAMES DUDLEY |
EP-0490282-B1 | 490,282 | EP | B1 | EN | 19,960,306 | 1,992 | 20,100,220 | new | F21V7 | F21V5, G09F13 | G09F13, F21V17, F21V5, F21V7, F21V13, F21S8 | G09F 13/04C, S09F13:14, G09F 13/14, F21S 8/00B2, F21V 17/04, F21V 13/04, F21V 5/02, F21V 7/00, F21V 13/10, S09F13:04R1, S09F13:14B | A lamp | The lamp (10) has a case (12) with a light exit opening (20). A reflector (22) is arranged on the rear wall (18) of the case (12) facing the light exit opening (20), in front of which an elongated light source (24) is arranged. Between the light source (24) and the light exit opening (20) there is a flexible optical film (30), stable in shape, with a smooth surface and a structured surface. The smooth surface faces the light exit opening (20), while the structured surface is directed toward the light source (24). The structure consists of a plurality of V-shaped grooves extending in parallel to each other and transverse to the longitudinal extension of the light source (24), the grooves lying immediately side by side. The optical film (30) extends only in that area in which the light source (24) emits light directly toward the light exit opening (20). | The invention relates to a lamp with a case having a light exit opening, an elongated source of light and a reflector. One requirement often to be met by lamps is that the light exit opening is illuminated evenly, i.e. without substantial variations in the concentration of luminance. This is particularly desirable with working place luminaires, but also with so-called light boxes in which the light exit opening is closed by a transparent plate that is back-lit. A light box in the sense of this application is a lamp having its light exit opening arranged in the case and closed by a plate or the like to be evenly back-lit. A lamp of the type initially mentioned is known from European Patent 0 350 436. The lamp has a case that is provided with a light exit opening and a reflector arranged on the inner wall opposite the light exit opening. In front of the reflector there is an elongated light source in the form of a fluorescent tube. A curved cover plate of transparent material is arranged between the light exit opening and the light source, which terminates at the inner walls of the case. On the outer surface facing to the light exit opening, the cover plate has a plurality of mutually parallel and adjacent V-shaped grooves extending transversal to the longitudinal extension of the light source. Since the flanks of the V-shaped grooves are immediately adjacent to each other, prism strips are formed, the flanks of which define the V-shaped grooves. With the known prism cover, only lamps with a comparatively narrow case can be realized, the case having a rather large constructional depth. All light beams emitted by the light source have to pass the transparent cover plate in order to exit via the light exit opening. The light exiting from the cover plate in the area closer to the light source is more intense than the light exiting from the remaining area of the cover plate. From CH-A-389 538 a lamp is known in which the light exit opening of the lamp body is closed by a rigid cover of glass. Within the lamp body an elongated light source is arranged. In the central area of the cover being closest to the light source, prism-like grooves are provided extending in longitudinal direction of the light source. Only a part of the light emitted from the light source directly towards the light exit opening passes the prism-like central part of the cover glass. In FR-A-921 846 another known lamp is disclosed provided with a body having a light exit opening. The light exit opening is completely covered by a transparent plate having prism-like grooves on its outer surface. The grooves extend transversally to the extention of the longitudinal light source located within the lamp body. It is an object of the invention to provide a lamp of the type mentioned above, in which the light exit opening is evenly illuminated. According to the invention, the object is solved by a lamp as defined in claim 1, providing a flexible transparent optical film, stable in shape, between the light exit opening and the light source, which has a smooth first surface and a structured second surface facing to the light source, and which is provided with mutually parallel and adjacent substantially V-shaped grooves extending transversal to the longitudinal extension of the light source, and by the optical film extending in the case only over an area in which the light source emits its light directly towards the light exit opening. According to the present invention, a flexible, dimensionally stable, optical film of a transparent material, preferably polycarbonate or polymethacrylate, is used for screening the light exit opening against light emitted by the light source directly towards the light exit opening. This optical film has a smooth surface on the one side and a structured second surface on the other side, which is provided with mutually parallel and adjacent substantially V-shaped grooves and prisms. The optical film is arranged or orientated such that its structured surface is facing the light source, the grooves and prisms extending transversal to the longitudinal extension of the light source. The optical film, which is arcuate in cross section and curved concavely with regard to the light source, and which extends along the light source, is arranged only in that region where the light from the light source is emitted directly towards the light exit opening. This area is determined by the geometry of the lamp, in particular by the size of the light exit opening, the distance between the light exit opening and the light source and the distance between the optical film and the light source. Due to the prism structure in the central portion of the light exit opening, seen in the direction of projection, facing the light source, the light that does not penetrate the optical film is reflected and distributed to both sides, where it contributes to an even illumination of the light exit opening, thus allowing to design it with a comparatively large surface. This even illumination of the large light exit opening is achieved although the constructional depth of the case is comparatively low. Due to the surface structure of the optical film, the light exits at different angles from the plane surface facing the light exit opening so that a comparatively uniform distribution of light occurs behind the optical film, seen in the direction of the diffusion of the light. The light exiting from the light exit opening is composed of light beams penetrating the optical film, possibly after multiple reflection by the film and the reflector, and such light beams that are reflected past the optical film towards the light exit opening after having been reflected at the reflector. Thus, the present arrangement and the orientation of the optical films with the V-shaped grooves and prisms achieve a uniform distribution of the light emitted from the light source directly towards the light exit opening. The main reason for this is that the light of the light source impinges on the optical film with its sawtooth-shaped cross section, which results in various light beam paths. Depending on the angle of incidence at which the light impinges on the structured surface of the optical film, a total reflection or a refraction occurs. The refracted light beams either exit from the plane surface of the optical film or they are reflected there in order to exit from the structured surface of the optical film. However, a total reflection of the light beams may also occur at the structured surface. This multiplicity of possible light beam paths makes the light reaching the light exit opening more even and allows a relatively even illumination of the light exit opening even if the same has a comparatively large surface. In principle, the prism and groove structure of the optical film is optional, provided that the prisms and grooves extend transverse, i.e. perpendicular, to the longitudinal extension of the light source. The optical properties of the optical film having the structure described above, however, are most favorable with a view to a more even distribution of the light, if the flanks of the grooves and prisms extend at an angle of 90 degrees with respect to each other, each flank extending at an angle of 45 degrees to the smooth surface of the optical film. Preferably, the grooves are of equal depth so that equal angle prisms (and thus equal angle grooves) are obtained. Preferably, an optical film that is designed for implementation in a lamp according to the present invention, has a thickness of about 0.5 mm, the depth of the grooves being about 0.17 mm and the distance between the grooves or the prisms being about 0.35 mm. Preferably, a plurality of optical films, in particular two optical films, are superposed, the structured surfaces of all optical films being directed towards the light source. By arranging a plurality of optical films one after the other, the distribution of the light is evened further. Preferably, all optical films are arranged concentric and centered with respect to each other, the width of the optical films decreasing as the distance of the optical films to the light source increases. The concentric and centered arrangement of the optical films evens the distribution of the light particularly in the central portion of high light intensity of the light exit opening, which is closest to the light source. Instead of arranging a plurality of optical films one after the other, it is contemplated in an advantageous embodiment of the present invention to provide a light-scattering diffusion plate on the smooth surface of the optical film facing the light exit opening, the plate possibly being arranged concentric and centered with respect to the film. The diffusion plate contributes to a further more even distribution of the light in the central portion of the light exit opening. The diffusion plate is preferably configured as a narrow plate strip lying on the optical film. Since a particular purpose of making the illumination of the light exit opening more even is to compensate the differences in light intensity of the central portion, which is closest to the light source, and the peripheral portions of the light exit opening, the diffusion plate, necessarily also attenuating the light, only extends over the central portion of the optical film. For the same reason, a plurality of optical films is always arranged in centered relationship in order to distribute the very light in the central portion to the peripheral portions. Preferably, the light source is a fluorescent tube, the optical film or the optical films and, if provided, the diffusion plate extending substantially concentric to the fluorescent tube. The optical film provided in the lamp of the present invention may advantageously also be implemented in a light box wherein one side or surface of the case carrying an information is lit from the rear. Typically, a light box is a lamp having its light exit opening closed by a transparent plate which is evenly backlit. According to an advantageous embodiment of the invention, a transparent support plate is arranged in the case for retaining the optical film, which is concave relative to the light source and which is arcuate in cross section. This transparent support plate carries the optical film on its inner surface facing to the light source, the film thus also being arcuate in extension. Should a diffusion plate or a further optical film be used in addition to the optical film, it is preferably arranged on the outer surface of the support plate facing the light exit opening. According to a further advantageous embodiment of the present invention, the optical film is retained by at least one holding element of transparent material which may be plugged on the light source and fixed thereon by clamping. The fixing of the optical films by clamping forces applied through holding elements to be plugged onto the light source offers advantages for the production of the lamp and for the retrofitting of installed lamps with a cover for the light source in the form of the optical film. The clamping force exerted by the holding element ensures a reliable and secure positioning of the film with respect to the light source and a fixation of the film in the position once taken. Advantageously, the transparent holding element of flexible material is provided with a clamp member to be plugged onto the fluorescent tube, enclosing more than 180 degrees, preferably up to 270 degrees, of the circumference of the fluorescent tube and having a spacing bar formed thereon which extends radial to the fluorescent tube when the clamp member is plugged onto the same. The free end of the spacing bar having a transversal supporting bar to which the optical film is fastened. The spacing bar defines the distance between the optical film and the fluorescent tube. The supporting bar may either extend rectangular to the spacing bar or it may be curved corresponding to the curvature of the optical film to be fastened thereon. On the one hand, the distance between the optical film and the light source, i.e. the height of the spacing bar of the holding element, depends on the diameter of the fluorescent tube and, on the other hand, on the distance of the fluorescent tube to the exit opening. The reflector of the lamp of the present invention may be a mat white plate or a conventional mirror reflector. The reflector should extend evenly on both longitudinal sides of the light source so that light from the light source exiting laterally is reflected towards the light exit opening in the same way and the same direction on both sides, thereby allowing a relatively wide light exit opening which is still evenly illuminated. Advantageously, an optical is also used as the reflector, having the same design and the same surface structure as the optical film of the cover of the lamp. Should an optical film be used as the reflector, the V-shaped grooves and prisms preferably extend perpendicular to the longitudinal extension of the light source, which is favorable for the even illumination of the light exit opening. Here, the grooves and prisms face to the light source. The following is a detailed description of an embodiment of the invention with reference to the accompanying drawings: Fig. 1is a view of the lamp seen from the side of the light exit opening, Fig. 2is a view along the line II-II in Fig. 1, Fig. 3a section along line III-III in Fig. 2, Fig. 4is an upscaled view of one of the holding elements with which the optical film is fixed to the fluorescent tube, Fig. 5is an upscaled illustration of a holding element with which the reflector is fixed to the fluorescent tube, and Fig. 6is an upscaled view of a holding element with which both the optical film and the reflector are fixed to the fluorescent tube. Figs. 1 to 3 illustrate the configuration of a lamp 10 according to the invention. According to Fig. 1, the lamp 10 has a substantially rectangular case 12 consisting of two parallel longitudinal side walls 14 and two mutually parallel transversal side walls 16 extending rectangularly to the longitudinal side walls. The rear wall 18 of the case 12 is curved outward, as illustrated in Fig. 2, while the front wall opposite the rear wall 18 has the light exit opening 20 provided therein. The light exit opening 20 extends over the entire front wall of the case 12. A reflector 22 is arranged on the inner surface of the curved rear wall 18, which lies on the rear wall 18. Arranged in the case 12, there is an elongated light source in the form of a fluorescent tube 24 extending in parallel to the longitudinal side walls 14 and over the entire length of the case 12. The fluorescent tube 24 is supported at its ends by the sockets indicated at 26. The fluorescent tube is located in the center of the rear wall 18 of the case and immediately in front of the reflector 22. A transparent screen 28 is provided between the fluorescent tube 24 and the light exit opening 20, which extends over the entire length of the case 12 and shields the fluorescent tube 24 against the light exit opening 20. This screen 28 consists of an optical film 30 having a plane surface and a structured surface. The optical film 30 consists of a transparent flexible material, stable in shape, thus having a certain flexural rigidity. The optical film 30 is curved arcuately. On the side of the optical film 30 facing the light exit opening 20, a diffusion plate 32 is arranged centered and concentric to the optical film. As can be seen in Fig. 3, the structured surface of the optical film is facing the fluorescent tube 24. The structured surface has substantially V-shaped grooves 34 provided therein which extend in parallel to each other and are immediately conterminous. Prisms 36 are formed between the V-shaped grooves 34, the two flanks of a prism 36 corresponding to the adjacent flanks of two adjacent V-shaped grooves 34. The orientation of the optical film 30 is such that the V-shaped grooves 34 and the prisms 36 extend transversal, i.e. perpendicular to the longitudinal dimension of the fluorescent tube 24. The flanks of the grooves and the prisms extend rectangularly with respect to each other, each flank extending at an angle of 45 degrees to the plane surface of the optical film. Since all V-shaped grooves are of equal depth, the prisms 36 are isosceles. As can be seen in Fig. 2, the optical film 30 only extends over that angular range in which the fluorescent light 24 emits light directly towards the light exit opening 20 of the case 12. In Fig. 2, the angular range of this light is indicated by the broken lines 38. All light emitted directly towards the light exit opening 20 will thus impinge on the V-shaped grooves, 34 and the prisms 36 of the optical film 30, where it is either reflected because of a total reflection or penetrates into the optical film 30, while being refracted. Light reflected from the optical film 30 impinges on the reflector 22 from which it is either reflected back to the optical film 30 or laterally past the optical film 30 towards the light exit opening 20. It is the effect of the arrangement of the optical film 30 between the light exit opening 20 and the fluorescent tube 24, as described and illustrated herein that, due to the reflection of the light at the optical film 30 and the transmission of the light through the optical film 30, the part of the light emitted by the fluorescent tube 24 that, without the optical film 30, would exit at the central portion of the light exit opening 20, is partly reflected or directed to both longitudinal sides of the elongated light source and thus distributed over the entire light exit opening 20. The strip-shaped diffusion plate 32 provided on the plane face of the optical film 30 which faces the light exit opening 20, causes an additional light scattering favorable to the even illumination of the light exit opening 20. As illustrated in the Figures, the reflector 22 also is an optical film of the same structure as the optical film 30 of the cover 28. The smooth surface of the optical film 40 of the reflector 22 lies on the inner surface of the rear wall 18, while the structured surface, formed by adjacent and mutually parallel substantially V-shaped grooves 42 and prisms 44, faces the fluorescent tube 24. The grooves 42 and prisms 44 of the optical film 40 extend transversal, i.e. perpendicular to the longitudinal axis of the fluorescent tube 24. The surface areas of the inner side of the rear wall 18 not covered by the optical film 40 are mat white. Due to the groove or prism structure of the optical film 40 of the reflector 22, the largest part of the light impinging on the reflector 22 in the immediate vicinity of the fluorescent tube 24 is not reflected back to the fluorescent tube 24, but past the fluorescent tube 24. Thus, this reflected light is not added to the light emitted from the fluorescent tube 24 directly towards the light exit opening 20, which also leads to a more even illumination of the light exit opening 20. As indicated in Figs. 1 to 3, the optical film 30 of the screen 28 and the optical film 40 of the reflector 22 are held by holding elements engaging at the fluorescent tube 24. While the optical film 30 of the screen 28 is held by two holding elements 46, as illustrated in Fig. 4, the optical film 40 of the reflector 22 is held by the three holding elements 48 (see Fig. 5). The holding elements 46 for the optical film 30 of the screen 28 consist of a transparent resilient material and have a clamp member in the form of a sleeve 50 which, at a circumferential portion, has a gap 51 extending axially over the length of the sleeve 50. In cross section, the sleeve 50 is C-shaped. The sleeve 50 may be plugged onto the fluorescent tube 24 by virtue of the gap 51 and encloses the tube in an angular range between 180 degrees and 270 degrees. When set onto the fluorescent tube 24, the sleeve 50 is spread. Due to the resilience of the material of the holding element 46, the sleeve 50 exerts a clamping force on the fluorescent tube 24 so that the holding element 46 is clampingly fixed to the fluorescent tube 24 through the sleeve 50. Diametrically opposite the gap 51, a radial spacing bar 52 is provided at the sleeve 50, the free end of which has a supporting bar 54 provided thereto, extending transversal to the spacing bar 52. The optical film 30 is glued to the supporting bar 54 by means of a transparent adhesive, the supporting bar projecting beyond the spacing bar 52 at both longitudinal sides. The supporting bar 54 is curved corresponding to the shape of the optical film 30. The holding element 48 is substantially the same as the holding element 46, differing only in that the radial extension of the spacing bar with respect to the sleeve is shorter than in the holding element 46. In general, the height of the spacing bars of the holding elements depends on the configuration of the lamp, in particular on the diameter of the fluorescent tube 24 and its distance to the light exit opening 20. Fig. 6 illustrates a holding element 56 used to fix both the optical film 30 of the screen 28 and the optical film 40 of the reflector 22 at the fluorescent tube 24. The holding element 56 has a clamp member similar to a sleeve 58, clampingly surrounding 180 degrees to 270 degrees of the circumference of the fluorescent tube 24 and having a longitudinal slot gap 59 of corresponding width. The sleeve 58 has two radially extending spacing bars 60, 62 formed thereon that are arranged diametrically opposite to each other and extending offset by 90 degrees with respect to the gap 59. According to Fig. 6, the gap 59 of the holding member 58 by virtue of which the holding member 58 is plugged onto the fluorescent tube 24, points to a direction perpendicular to the radial extension of the spacing bars 60, 62. At the free end of the spacing bar 60, the supporting bar 64 for supporting the optical film 30 is arranged, while at the free end of the spacing bar 62 that is shorter than the spacing bar 60, the supporting bar 66 for supporting the optical film 40 is arranged. Further, it should be mentioned that, in the Figures, the thickness of the optical film and the surface structure thereof are not represented in their real dimensions with respect to the other parts of the lamp since, if the Figures were true to scale, the optical film would not be visible anymore. Also the distance between the fluorescent tube and the reflector is not true to scale. | A lamp comprising a case (12) having a light exit opening (20), an elongated light source (24), and a reflector (22), characterized in that a flexible transparent optical film (30), stable in shape is arranged between said light exit opening (20) and said light source (24), said film having a smooth first surface and a structured second surface facing said light source (24), which second surface is provided with mutually parallel and adjacent substantially V-shaped grooves (34) extending transversal to the longitudinal extension of said light source (24), and said optical film (30) extends only over an area within said case (12), in which all the light, emitted by said light source (24) directly towards said light exit opening (20), is emitted. The lamp of Claim 1, characterized in that a plurality, in particular two, optical films (30) are arranged in superposition, the structured surfaces of all optical films (30) pointing to the light source (24). The lamp of Claim 2, characterized in that all optical films (30) are arranged concentric and centered with respect to each other, and that the width of the optical films (30) decreases as their distance to the light source (24) increases. The lamp of Claim 1, characterized in that a diffusion plate (32) is provided on the smooth surface of the optical film (30) facing the light exit opening (20), the diffusion plate being arranged concentric and centered relative to the optical film. The lamp of Claim 4, characterized in that said diffusion plate (32) is narrower than the optical film(30) on which it is arranged. The lamp of one of Claims 1 - 4, characterized in that the optical film(s) (30) consist(s) of polycarbonate or polymethacrylate. The lamp of Claim 6, characterized in that said light source (24) is a fluorescent tube. The lamp of Claim 7, characterized in that the optical film(s) (30) extend(s) concentric with respect to the fluorescent tube. The lamp of one of Claims 1 - 8, characterized in that the light exit opening (20) is closed by a transparent plate back-lit by the light from the light source (24). The lamp of one of Claims 1 - 9, characterized in that a transparent support plate is arranged in the case (12), said plate being concavely curved relative to the light source (24) and supporting the optical film (30) on its inner surfaces facing said light source (24). The lamp of Claims 4 and 10, characterized in that the support plate has the diffusion plate (32) provided on its outer surface facing the light exit opening (20). The lamp of one of Claims 1 - 9, characterized in that the optical film (30) or, in the case of a plurality of optical films, one of the optical films (30) is fastened to at least one holding element (46) of transparent material that may be plugged onto said light source (24) and may be fastened thereto by clamping. The lamp of Claims 7 and 12, characterized in that said holding element (46) consists of resilient material and has a clamp member (50) which may be plugged onto the fluorescent tube and surrounds the fluorescent tube over more than 180 degrees, preferably up to 270 degrees, of its circumference and at which a spacing bar (52) is provided, having a supporting bar (54) formed at its free end, to which the optical film is fastened. The lamp of Claim 12 or 13, characterized in that the optical film (30) is glued to the at least one holding element (46) by means of a transparent adhesive. | MINNESOTA MINING & MFG; MINNESOTA MINING AND MANUFACTURING COMPANY | DE LA CRUZ CARCIA ALBERTO; SIMMONS ADRIAN; DE LA CRUZ CARCIA, ALBERTO; SIMMONS, ADRIAN |
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