There is disclosed an amplifier circuit providing a stable gain independently of fluctuations in power supply voltage, in which resistors (13, 14) and corrective switches (25, 26) having the same construction as analog switches (21 to 24) are provided in a feedback path from an output of an operational amplifier (1) to a negative input thereof, and in which resistors (15, 16) and corrective switches (27, 28) having the same construction as the analog switches (21 to 24) are provided in a reference voltage positive input path from a positive input of the operational amplifier (1) to a reference voltage (VR). An L level logical signal is applied to control inputs (C) of the corrective switches (25 to 28) and an H level logical signal is applied to control inputs (D) thereof. The corrective switches (25 to 28) are constantly set to an ON-state under the same conditions as the analog switches (21 to 24) in the ON-state.

1. Field of the Invention
The present invention relates to an amplifier circuit used as a balanced modulating circuit such as a ring modulating circuit.
2. DESCRIPTION OF THE BACKGROUND ART
FIG. 2 is a circuit diagram of a conventional differential amplifier circuit used as a ring modulating circuit which is a type of balanced modulating circuit. One end of a resistor 11 is connected to a negative input of an operational amplifier 1, and one end of a resistor 12 is connected to a positive input thereof. Resistors 13 and 14 connected in series are provided in a feedback path from the output of the operational amplifier I to the negative input thereof. Resistors 15 and 16 connected in series are provided in a reference voltage positive input path from the positive input of the operational amplifier 1 to a reference voltage VR. The resistors 11 to 16 have the same resistance.
An input signal SI to be modulated is applied to a signal input terminal 31, and a control signal SC is applied to a control signal input terminal 32. The output of the operational amplifier 1 is outputted from an output terminal 33 in the form of an output signal SO provided by the modulation of the input signal SI. An inverter 2 receives the control signal SC and inverts the logical level of the control signal SC to output an inverted control signal SC.
Analog switches 21 to 24, shown in FIG. 2, are of the same internal construction, which is shown in FIG. 3. Referring to FIG. 3, each analog switch includes PMOS and NMOS transistors 41 and 42 which share first and second electrodes serving respectively as an input A and an output B. A signal given from a control input C is applied to the gate of the PMOS transistor 41, and a signal given from a control input D is applied to the gate of the NMOS transistor 42.
The input A of the analog switch 21 is connected to the signal input terminal 31, and the output B thereof is connected to the other end of the resistor 11. The reference voltage VR is applied to the input A of the analog switch 22, and the output B of the analog switch 22 is connected to the other end of the resistor 11. The input A of the analog switch 23 is connected to the signal input terminal 31, and the output B thereof is connected to the other end of the resistor 12. The reference voltage VR is applied to the input A of the analog switch 24, and the output B of the analog switch 24 is connected to the other end of the resistor 12.
The control signal SC is applied to the control inputs C of the analog switches 21 and 24 and to the control inputs D of the analog switches 22 and 23. The inverted control signal SC is applied to the control inputs C of the analog switches 22 and 23 and to the control inputs D of the analog switches 21 and 24.
The ring modulating circuit is a differential amplifier circuit having such construction that varies the logical level of the control signal SC at the frequency of a predetermined carrier wave in order, signal SO, the modulated signal provided by the balanced modulation of the input signal SI
The amplification operation of the amplifier circuit will be described below. It is assumed that the reference voltage VR is 0 V. Reference character VI designates the voltage of the input signal SI; VO designates the voltage of the output signal SO; R designates the resistances of the resistors 11 to 16; and r designates the ON-resistances of the analog switches 21 to 24.
When the control signal SC is at the L level (or ground level), the analog switches 21 and 24 are on and the analog switches 22 and 23 are off. The input signal SI is applied to the negative input of the operational amplifier 1 through the resistor 11, and the reference voltage VR is applied to the positive input of the operational amplifier I through the resistor 12. As a result, the differential amplifier circuit functions as an inverting amplifier circuit, so that the output voltage VO is determined as: EQU VO=-{2R/(R+r)}.multidot.VI (1)
When the control signal SC is at the H level (or power supply voltage level), on the other hand, the analog switches 21 and 24 are off and the analog switches 22 and 23 are on. The input signal SI is applied to the positive input of the operational amplifier I through the resistor 2, and the reference voltage VR is applied to the negative input of the operational amplifier 1 through the resistor 11. As a result, the differential amplifier circuit functions as a noninverting amplifier circuit, so that the output voltage VO is determined as: EQU VO={2R/(R+r)}.multidot.VI (2)
From Formulas (1) and (2), the gain G of the differential amplifier circuit is: EQU G=2R/(R+r) (3)
The gain G is determined by the resistances R of the resistors 11 to 16 and the resistances r of the analog switches 21 to 24.
The conventional differential amplifier circuit used as the ring modulating circuit is constructed as above described. One of the parameters to determine the gain of the differential amplifier circuit is the ON-resistances r of the analog switches 21 to 24.
The ON-resistances of the PMOS and NMOS transistors 41 and 42 constituting the analog switches 21 to 24 depend mainly on a gate voltage and are inversely proportional to the square of the power supply voltage, varying with fluctuations in power supply voltage.
Therefore, the conventional differential amplifier circuit has a problem in that the gain thereof varies with fluctuations in power supply voltage.

Amplifier circuit with gain that does not vary with power supply fluctuations


A joint sealing tape preferably has the following composition in mass %: 35 to 36% of a premix comprising 73 to 75% of a soft grade of bitumen, 18 to 19% rubber and 7 to 8% of comminuted tire rubber; 31 to 32% of a soft ge of bitumen; 19 to 20% ground slate; 11 to 12% cellulose powder; and 2% silicon dioxide.

The invention relates to a joint sealing tape for asphalted areas, such as asphalted roads and pathways, comprising a molded mixture of bitumen, fillers and permanently adhesive polymers not including a carrier, i.e., a solvent. In addition, the invention relates to a joint sealing system based on the said joint sealing tape. In contrast to a large group of prior art elastomer sealing tapes, designed as specific, mainly complex sections, in particular used in concrete joints (see DE 89 14 261 U1, for instance), the plasticity and adhesive strength of the bitumen components is exploited in order to allow sealing of irregularly shaped joints.
Based on optimum selection of dimensional stability for transport and storage on the one hand and plasticity and adhesive strength for the actual sealing function on the other, joint sealing tapes of the type described above may eliminate additional expenses for the use of one or two substrate tapes (DE 38 43 574 C2; DE 44 03 101 A1) for layers of different elasticity for adaptation to the joint walls (DE 30 45 738 C1) or for a special coat of adhesive (DE 196 03 896 A1).
The documented state of technology, as shown in FIGS. 3 to 6, in which a sealing tape 5 is inserted vertically into a joint between two asphalt layers 1.1 and 1.2 and is rolled into a mushroom or hat shape 5.1 (FIG. 4), is general knowledge. It is easy to see that the joint width and cross sections of any sealing tape used must be accurately adapted to each other, i.e. over the full length of the joint, a feature which is hard to maintain in the construction industry. Tight sealing, as shown in FIG. 4, can in fact only be randomly achieved when a vertically arranged joint sealing tape accurately fills the joint, projecting from it by approximately 1 cm. When a joint sealing tape is too thick, it cannot be inserted into a joint. When it is too wide, it will project too far over the joint and is not being flattened by rolling but rather "folded over" (both conditions not shown). Finally, FIGS. 5 and 6 show the case of a joint sealing tape 5 which is too narrow, although it is easy to introduce into a joint but does not fill the joint. In winter in particular, cracks 6 occur in a rolled joint in accordance with FIG. 6 on either side of the joint sealing tape 5. In all cases, including the "randomly" sealing tape of FIGS. 3 and 4, the bottom section of the joint sealing tape is superfluous, cannot contribute to its sealing function and should actually be avoided in the interest of saving resources.
Finally, a molded, non-carrier, bitumen-based sealing material is prior art, which may be used as joint sealing tape, predominantly comprising soft bitumen, rubber flakes, stone dust, an oil-type mineral oil fraction and a short-fiber filler, such as cellulose powder (DE 93 13 030 U1). The composition of this sealing material comprises soft and harder grades, with the latter being provided for pre-cast concrete construction and not necessarily suitable for asphalted areas without any additional processing.

Joint sealing tape for asphalted areas and joint sealing systems based on the same

BITUTEC Bitumen-Technik Service und Vertriebsgesellschaft mbH


A scroll compressor has first, second and third scrolls. The second and third scrolls each have a spiral ridge on a flat plane and the first scroll has two spiral ridges on opposite sides of a flat plate. The second and third scrolls are arranged on both sides of the first scroll so that the spiral ridges of the opposed scrolls are meshed with each other. A lower-stage compression part is defined between the first and second scrolls and a higher-stage compression part is defined between the first and third scrolls. A suction port of the lower-stage compression part communicates with a suction passage of the compressor, a discharge port of the lower-stage compression part communicates with a suction port of the higher-stage compression part, and a discharge port of the higher-stage compression part communicates with a discharge passage of the compressor. Thus, a fluid on the suction passage is first sucked into the lower-stage compression part and compressed there to an intermediate pressure, then further compressed to a higher pressure at the higher-stage compression part, and finally discharged from the discharge port of the higher-stage compression part to the discharge passage.

1. Field of the Invention
The present invention generally relates to a scroll compressor primarily used for a refrigerating apparatus, and more particularly to a scroll compressor comprising a first scroll, and second and third scrolls arranged on both sides of and associated with the first scroll so that two compression chambers are provided.
2. Description of the Prior Art
A conventional scroll compressor of this kind is disclosed in FIG. 9. As shown in FIG. 9, the conventional scroll compressor comprises a first scroll 102, a second scroll 103 and a third scroll 104. The first scroll 102 has a flat plate 121 and back and front spiral ridges 122a, 122b provided on both sides of the flat plate 121, respectively. The second scroll 103 has an end plate with a flat face 131 confronting one face of the flat plate 121, and a spiral ridge 132 provided on the flat face 131. Similarly, the third scroll 104 has an end plate with a flat face 141 confronting the other face of the flat plate 121 of the first scroll 102, and a spiral ridge 142 provided on the flat face 141. The second and third scrolls 103, 104 are arranged on both sides of the first scroll 102 in a manner to sandwich the first scroll 102 therebetween. Thus, the back spiral ridge 122a of the first scroll 102 and the spiral ridge 132 of the second scroll 103 are meshed with each other, while the front spiral ridge 122b of the first scroll 102 and the spiral ridge 142 of the third scroll 104 are meshed with each other. Suction ports 105, 105 are respectively formed in the vicinity of the external end portions of the back spiral ridge 122a of the first scroll 102 and the spiral ridge 132 of the second scroll 103 and in the vicinity of the external end portions of the front spiral ridge 122b of the first scroll 102 and the spiral ridge 142 of the third scroll 104. The suction ports 105 communicate with a suction space 106 in a casing 101 being a low-pressure dome. On the other hand, discharge ports 108, 108 are respectively formed in the vicinity of the internal end portions of the back spiral ridge 122a of the first scroll 102 and the spiral ridge 132 of the second scroll 103 and in the vicinity of the internal end portions of the front spiral ridge 122b of the first scroll 102 and the spiral ridge 142 of the third scroll 104. The discharge ports 108 communicate with a discharge passage 107. Compression portions 109, 109 are defined between the spiral ridges 122a and 132, 122b and 142. In this scroll compressor, a fluid taken in from the respective suction ports 105 and compressed at the respective compression portions 109 is joined at the discharge ports 108 and then discharged through the discharge passage 107 communicating with the discharge ports 108.
As described above, in the conventional scroll compressor, the suction and compression operation is effected on both sides of the first scroll 102. Therefore, a thrust load acting on the first scroll 102 is offset by the balance between fluid pressures at the compression chambers formed on both sides of the first scroll 102, so that a thrust load acting on a thrust bearing of the first scroll 102 can be reduced, resulting in reduction of loss at the thrust bearing. In addition, the capacity of the compressor can be increased.
However, since a fluid, which is in the suction space 106 in the casing 101 designed as a low-pressure dome, is taken in from the two suction ports 105 communicating with the suction space 106, and compressed at the two compression portions 109 in parallel and then discharged from the two discharge ports 108 to the discharge passage 107, the volumetric efficiency cannot be effectively increased. More specifically, since a vicinity zone of the external end portions of the spiral ridges 122a and 132 and that of the external end portions of the spiral ridges 122b, 142 are both placed in an atmosphere of a suction pressure, both of the compression portions 109 having completed the fluid suction and containment processes are necessarily adjacent to the suction space 106. As a result, as shown in FIG. 10, the fluid under compression in the two compression portions 109 leaks to the suction space 106 through clearances between end faces of the external end portions of the spiral ridges 122a, 122b of the first scroll 102 and the flat faces 131, 141 of the end plates of the second and third scrolls 103, 104, respectively. Since this leakage takes place on both sides of the first scroll 102, the volumetric efficiency decreases.

Scroll compressor of two-stage compression type having an improved volumetric efficiency


This hearing aid system comprises a first hearing aid (1) and the second hearing aid (2) mounted on the right ear. These each have a microphone (101) for inputting ambient sound, a hearing aid processor (102) for subjecting sound inputted from the microphone (101) to hearing aid processing, a speaker (103) for outputting sound that has undergone the hearing aid processing, a communication component (107) for performing wireless communication, and a battery (104) for supplying electrical power to the microphone (101), the hearing aid processor (102), the communication component (107), and the speaker (103). The first hearing aid (1) and the second hearing aid (2) have a battery charge detector (105) for detecting the remaining charge of the battery. A power consumption controller (106) is provided for reducing the power consumption for whichever of the first hearing aid (1) and the second hearing aid (2) that has the lowest remaining battery charge when it has been detected that the difference in the remaining battery charges of the first hearing aid (1) and the second hearing aid (2) detected by the battery charge detector (105) is greater than a specific value.

A conventional hearing aid has a mode switching function in which the hearing aid characteristics are modified to suit the surrounding environment. When such hearing aids are mounted on both ears, the left and right hearing aid effects need to be balanced to avoid causing the user discomfort. In view of this, there has been disclosed a hearing aid system in which the hearing aids mounted on the two ears communicate wirelessly with each other to synchronize mode switching (see Patent Literature 1, for example).


A disclosure pertains to a reciprocating pump configured for pumping fillers or aggregates or cementitious material and the like.

Two ball piston pumps have not traditionally been used for pumping heavy fillers or aggregates or cementitious material and the like. Problems associated with restricted flow passages as well as the inability of ball check valves to seal properly in a heavily aggregate filled material are common. When cementitious material is put under pressure the water or fluid contained within the material can separate out from the aggregate portion of the material which leads to a compressed or hardened mass that is no longer flowable, and it is considered packed out. Packed out material prevents the pump from working. Additionally, pumping heavily filled material requires valves, e.g., check valves, that seal adequately to prevent water or fluid within the material from separating out.
U.S. Pat. No. 2,309,839 to Gardner discloses a float collar utilized in lowering strings of pipe into a well bore using floating equipment. The float collar is made of a deformable rubber body which is inserted into the pipe without performing any operations on the pipe such as threading, welding, etc. After the rubber body is inserted in position, it is arranged to permit its expansion so that the inherent resiliency of the rubber causes it to grip inside of the pipe and hold the pipe in position. Also disclosed is providing a rubber float collar and a rubber float shoe having a body made of resilient material such as rubber and having a diameter substantially in excess of the inside diameter of the string of pipe to which it is applied so that the body may be compressed, inserted in the pipe, and permitted to expand so that its inherent resiliency creates a frictional grip with the inside surface of the pipe to hold the body in position. Additionally, a rubber float collar or guide shoe is disclosed which can be temporarily deformed and retained in such deformed position so that it may be inserted in a pipe to thereafter expand and grip the pipe. The disclosure further provides a rubber float collar which can be deformed and temporarily retained in such deformed position by a restraining means or by means of a wire or metal sleeve which can be thereafter released by corrosion or otherwise so as to release the body.
U.S. Pat. No. 2,682,281 to Ecker relates to ball check valves and, more particularly, a ball valve provided with a cage having a flexible and resilient ball guide. The flexible and resilient ball guide includes circumferentially spaced guide elements adapted to receive the ball valve therebetween, the circumferential spaces between the guide elements providing passages past the ball valve through which fluid may flow when the ball valve is in its open position. Also disclosed is a unitary ball guide wherein the circumferentially spaced guide elements are interconnected so that the ball guide may be readily assembled with, or disassembled from the body of the ball valve cage. The guide elements of the ball guide are interconnected by arcuate connecting elements which co-operate with the guide elements at one end of the ball guide to form an annulus at the one end of the ball guide. To facilitate assembly of the ball guide with the body of the ball valve cage, at least the arcuate connecting elements defining the annulus are formed of a material which is considerably more flexible and softer than the guide elements.
U.S. Pat. No. 2,723,679 to Harris et al. teaches check valves for compressed air lines to regulate and control air pressure tanks, and more specifically a check valve which is preferably vertically positioned in the air line and is so designed and arranged that it will give instant opening and quick cut-off and provide a positive self cleaning action. The valve is useable in air controlled operations where a positive and quick acting check valve is required in the air line between the compressed air tank and the mechanism operated by the air. The check valve is in the form of a ball which is operative within a cage which includes a seat. The valve mechanism itself is mounted and arranged in vertical position, that is the valve mounting portion of the assembly is mounted in a vertical section between two horizontal sections of the entire compressed air line assembly. The guide or cage in which the valve is operable is formed integral with the valve bumper which provides for ease of assembly and replacement. The valve seat is designed for effecting an easy and rigid association with the compressed air line, and in a manner which expedites the removal in a quick and easy way of the seat from the assembly and also affords an easy replacement of a valve seat. The rapid deterioration of the prior art valve and parts thereof caused by foreign matter is overcome by constructing a valve wherein the ball is subjected to a spinning action in its opening and closing movements. The spinning action also causes the ball to be self cleaning to thereby eliminate substantially all corrosion which does form on valves. The air line is of angular construction forming a vertical section between two horizontal sections. The valve mechanism is operatively mounted in the vertical section. When the pressured air is flowing through the system it passes from a horizontal into the vertical section and this angular flow creates air turbulence in the vertical section which lifts the valve and generates a spinning reaction therein. This spinning action is also aided by the construction of the bumper at the top of the ball cage or guide which the ball valve engages at the top of its opening stroke.
U.S. Pat. No. 3,077,204 to Bennett et al. discloses one-way check valves for controlling the flow of fluids and more particularly a check valve suited to controlling the flow of granular fluid materials, such as plaster and cement slurry. The check valve is constructed such that granular particles in the material flowing through the valve cannot prevent the valve from closing completely. Also disclosed is a check valve which is adjustable to vary the distance of travel of its check valve member between open and closed positions so as to adapt the valve to use in a constant delivery plaster and cement spray pump.
U.S. Pat. No. 3,371,352 to Siposs et al. pertains to a heart valve having needle fixation in combination with an upholstered suturable cuff. The needles are pivotally mounted to swing in a common radial plane and have arcuately curved shanks concentric with their pivotal axes to avoid a sweeping motion as they penetrate the patient's tissue. The needles are projected by an epi-cycloidal cam on a rotatable ring in the valve.
U.S. Pat. No. 3,387,625 to Laure discloses a check valve construction having a ball check valve located between a pair of spaced apart annular constricting rings embracing a deformable tubular member forming deformations on the interior thereof, one of the deformations forming a valve seat for the ball valve member. The deformations are capable of being removed from the tubing and moved axially of the tubing.
U.S. Pat. No. 3,542,155 to Kern relates to a ball check valve type of lubrication fitting having a unitary tubular housing formed of a resilient deformable material with a series of axially spaced outwardly extending concentric ribs circumferally formed on the exterior surface of the housing for engaging the interior wall surfaces of a complementary mounting opening and deforming in a manner to retain the fitting in the opening.
U.S. Pat. No. 3,620,228 to Schmid relates to a device for attaching in the pipes of irrigating systems for removing silt and draining water composed of a tee for inserting in pipeline, a long drop pipe accommodating a valve seat, interior longitudinal flanges above said seat, and a buoyant captive ball between; ball being forced to seat under water pressure and rising when pressure is relieved, permitting silt and water to pass into open end sump below.
U.S. Pat. No. 3,661,167 to Hussey teaches a diaphragm or piston type chemical feed pump having an influent valve and an effluent valve connected to the pumping chamber each having in some combination a single or multiple ball check valve system. The valves of the pump are doubled and reversible within separable casings having oppositely disposed ball recesses so that the same set of parts can be assembled into an inlet or outlet ball check valve. For precise sealing, each valve has a resilient, self cleaning ball valve seat.
U.S. Pat. No. 4,286,622 to Ninomiya et al. pertains to a check ball valve assembly including a main valve body member taking the form of a rigid combination of a hollow cylindrical body element and a pipe coupling member at one end of the body element. The main valve body contains therein a movable ball valve member. In this valve assembly a further or second pipe coupling member is detachably connected at the opposite end of the body element. A resilient or elastomeric, double-functioning sealing member is positioned between the body element and the second pipe coupling and is so shaped and arranged to execute at its inside a detachable sealing function with the ball valve member and at the same time to execute at its outside a sealing function between the main valve body and the detachable pipe coupling member. The valve assembly further includes a retainer ring positioned stationarily behind the sealing member when seen in the regular fluid passage direction of the valve assembly. The retainer has a central tapered, fluid passage allowing bore, for engagement with the valve ball member for preventing an excess pressure contact of the latter with the sealing member. In the valve assembly, there are no 0 rings fitted therein.
U.S. Pat. No. 4,287,912 to Hewett discloses a monoflow ball valve that is particularly suited using plastic materials that resist metal-corrosive acids, as in a spray system using hydrofluoric acid and the like. The valve has a valve body with a passage section smaller than the external diameter of the ball and the ball is forced into the generally cylindrical passage section to become a highly effective fluid-tight seal. A spacer at the inlet forms with the ball a second fluid-tight seal and is adjustably movable to dislodge the ball from the passage section if required.
U.S. Pat. No. 4,295,412 to Hachiro teaches a hose with a one-way valve used in a brake actuating system for automobiles. A one-way valve unit is housed in a flexible hose for connecting a booster shell of a servomotor with an intake manifold of the internal combustion engine so as to prevent leakage of vacuum. A valve housing receives therein a valve member and a valve spring thereby forming the one-way valve unit. The housing further has a valve seat, a cylindrical guide portion and an annular seal projection of diameter larger than the guide portion. A fastening band is provided on the outer periphery of the hose to prevent movement of the one-way valve and is marked with a mounting direction of the hose.
U.S. Pat. No. 4,611,374 to Schnelle et al. pertains to a check valve formed integrally with a tube without requiring any additional components. The ball or poppet of the check valve is maintained in position via a magnetic mandrel while the tube is crimped at both sides of the poppet. The tube is inwardly crimped to prevent the poppet from being displaced in either direction and simultaneously to allow flow to bypass the poppet in the desired flow direction. Thereafter the poppet is physically displaced against one of the crimped indentations to coin a seat such that the poppet and the seat coact to prevent flow of fluid in the undesired direction.
U.S. Pat. No. 4,667,696 to van Rensburg relates to an adjustable nonreturn ball valve for connection in a pipeline. The valve includes an elongate unobstructed main housing arranged to be connected at each end to flow pipes. There is an auxiliary housing located intermediate the ends of the main housing which has a longitudinal axis obtuse to the longitudinal axis of the main housing. There is a removable circular valve seat extending across the main housing at an obtuse angle relative thereto. The main housing is formed in two sections which are joined together at the plane of the valve seat. A ball is positioned to close upon the valve seat and is loosely entrapped in the auxiliary housing to allow flow in only one direction through the main housing, in which event and in use the ball automatically rides up in the auxiliary housing and away from the valve seat. The ball and the auxiliary housing have diameters greater than the diameter of the main housing, thereby preventing the ball from moving through the main housing. The junction of the auxiliary housing and the main housing form a ramp to assist in moving the ball into the auxiliary housing in response to flow through the main housing. There is an adjustable, mechanically operable closure device for the valve which fits at an upper end of the auxiliary housing and is arranged to urge and hold the ball downwards toward the valve seat to throttle or close off the valve according to the setting of the closure device.
U.S. Pat. No. 4,955,407 to Inoue discloses the valve body construction of a check valve which is insertable into the interior of a flexible hose, which valve body comprises a valve body portion having one of an inlet port and an outlet port, and a valve end piece having the other of the inlet and outlet ports, wherein the valve end piece is formed with annular grooves extending in the circumferential direction thereof along the opposite sides across a joint surface between the valve body portion and the valve end piece. The outer diameter of the valve body portion is made slightly greater than the inner diameter of the hose, the valve end piece being provided with a gradually enlarged diametered portion having a largest outer diameter equal to or slightly greater than the outer diameter of the valve body portion, and also with a shouldered portion behind the largest outer diametered portion
U.S. Pat. No. 5,139,047 to Reinicke relates to a miniaturized check-valve having a length of straight cylindrical tubing for its body, wherein the open ends of the tube are the inlet (or upstream) and outlet (or downstream) ports of the valve. The tubular body is locally deformed to fixedly retain an inserted annular valve-seat member at a first axial location of downstream offset from the inlet end of the pipe. The tubular body is also locally deformed, at a second axial location of upstream offset from the outlet end of the pipe, to fixedly retain another annular member which serves to establish a fixed reference for the downstream end of a compression spring which continuously urges a valve member into its valve-closing relation with the valve-seat member.
U.S. Pat. Nos. 5,649,360 and 5,653,258 to Schwarz teach a vent valve for a thermostatic valve of a coolant circuit of an internal combustion engine having a ball with a radius and a diameter and serving as a sealing element, and a one-piece metal cage for the ball. The cage has a pot-shaped part with an inside diameter larger than the diameter of the ball, and a bottom having a valve opening surrounded by an outwardly projecting neck. The cage is shaped in one piece from an originally flat metal sheet by stamping, deep-drawing, and pressing, and the pot-shaped part has a height approximately the radius of the ball, and an edge abutted by a plurality of uniformly distributed tabs located on an axial extension of the pot-shaped part, the tabs having inwardly bent ends to retain the ball in the cage with play, the length of the tabs being greater than or equal to the height of the pot-shaped part.
U.S. Pat. No. 5,785,083 to Tang pertains to a check valve connectable in a refrigerant line and fabricated from only four parts—(1) a copper tubing body connectable in the refrigerant line, (2) a nonmetallic shutoff ball, (3) an annular valve seat member having a diametrically opposite pair of leg portions axially projecting from one end thereof, and (4) an annular stop member also having a diametrically opposite pair of leg portions axially projecting from one end thereof, and further having a diametrically opposite pair of axially extending outer side surface grooves formed therein. The seat and stop members are locked together to form a cage structure by axially press-fitting the valve seat member outer leg ends into the stop member grooves in a manner such that the stop member legs underlie and support the seat member legs, with outer ends of the stop member legs facing a conical seating surface of the seat member in an axially spaced relationship therewith. The shutoff ball is captively retained laterally between the seat member legs for axial movement within the cage structure between an open position in which the ball seals against the seating surface, and an open position in which the ball is axially moved away from the seating surface and is stopped by the outer ends of the stop member legs. The cage is coaxially and captively retained in a longitudinally central portion of the copper tubing body between two elongated, spun-down, reduced diameter end portions thereof that may be soldered into a refrigerant line.
U.S. Pat. No. 6,267,137 B1 to Watanabe et al. teaches a ball check valve having a body having a flow path and a turnout path formed therein and provided on a primary side thereof with an inlet and on a secondary side thereof with an outlet. A ball in the body a seating part for the ball, disposed in the inlet of the body and inclined toward the primary side in a state having the flow path laid horizontally, and a guide part provided with a part for causing the ball seated at the seating part to be retracted into the turnout path and guiding the retracted ball to the seating part, are provided. A pumping apparatus for discharging a fluid from a storage tank includes a pump alternating motions of pumping and stopping for controlling the fluid in the storage tank to a predetermined amount, a piping for discharging to the exterior the fluid of the storage tank being forwarded by the pump, and a ball check valve disposed on the piping and adapted to prevent the discharged fluid from flowing backward during stoppage of the pump.
U.S. Pat. No. 8,146,618 B2 to Szuster pertains to a valve wherein a supporting blind of a deflected channel is terminated at its free ends with oblique surfaces, and a guiding rail of the ball is terminated with the supporting directional arrangement directing the ball toward the supporting blind of the deflected channel, and the top, which is positioned closer to the valve outlet than to the inlet, and together with the oblique surfaces of the supporting blind of the deflected channel produce a slot widening itself to the direction of deflected channel interior.
U.S. Patent Application Publication No. 2005/0121084 A1 to Andersson discloses a ball check valve comprising a housing having walls defining a fluid inlet, a fluid outlet, and a chamber communicating with the inlet and with the outlet. The ball check valve includes a spherical hollow ball housing a plurality of spherical shock absorbing members that stabilize the spherical hollow ball during operation of the valve. The spherical hollow ball moves between a first, flow impeding position adjacent the inlet and a second position spaced from the inlet laterally of a fluid passageway in the chamber.
U.S. Patent Application Publication No. 2010/0206404 A1 to Morrison et al. relates to a ball check valve configured for use as a pressure vessel. In one embodiment of the invention, the ball check valve comprises a housing defining one or more inlet, an outlet and a passageway therebetween. A ball support system is mounted within the housing, wherein one or more balls are supported by the ball support system. The ball support system is configured to allow a ball to close off and open a respective inlet. The housing generally comprises an inlet section which can have one or more inlets, wherein each inlet defines a ball seat sealingly engageable with a ball for sealing the inlet. The housing further comprises a center section providing adequate space to allow movement of the ball and an outlet section comprising an outlet for transferring the fluid to a subsequent portion of a piping network. The ball support system is configured to guide the movement of each of the one or more balls, wherein the movement of each ball is guided from a first position wherein the ball is proximate to a ball seat located at an inlet and thereby sealing that inlet, to a second position wherein fluid flow through an inlet into the valve is enabled.
U.S. Patent Application Publication No. 2014/0026987 A1 to Ayers et al. teaches a relief valve for extracting sub-surface gas from beneath a geomembrane includes a valve body for permitting gas to flow therethrough and includes an inlet, an outlet, a vertical run communicating with the inlet, and a lateral run communicating with the vertical run and the outlet. A ball valve comprising a ball seat is positioned within the vertical run. A lightweight valve ball is positioned within the vertical run. The valve ball is movable therewithin between a lowered position against a ball seat and an elevated position distal therefrom. The valve ball is lightweight enough that minimal upward gas flows within the vertical run cause the valve ball to rise and become unseated from the ball seat such that stoppage of such vertical flows or reverse flows cause the valve ball to drop back to its ball seat and seal against reverse flows through the ball valve.
Accordingly, there exists a need for two ball piston pumps for pumping heavy fillers or aggregates or cementitious material and the like that are specifically designed to reduce the likelihood of creating compressed or hardened and packed out material. Additionally, in such piston pumps there exists a need for valves that seal adequately to prevent water or fluid within the material from separating out when pumping heavily filled material.


An adaptive array antenna controller is disclosed that adaptively controls weighting coefficients of multiple antenna elements of an array antenna based on a digital signal outputted from an analog-to-digital converter receiving a weighted analog signal received from the array antenna. The controller includes an impulse response measuring device for obtaining impulse responses, based on correlation calculation of the digital signal and a known signal having a predetermined pattern; an impulse response generator for extracting path components existing within a predetermined time duration from among plural path components included in the impulse responses and generating desired impulse responses; a reference signal generator for forming a reference signal having a desired pattern, based on convolution calculation of the desired impulse responses and the known signal; and an adaptive controller for adjusting the weighting coefficients, based on the digital signal and the reference signal.

1. Field of the Invention
The present invention relates to an adaptive array antenna controller.
2. Description of the Related Art
Transmission signals in mobile communication system are transmitted in a multipath transmission environment. In order to demodulate received signals well, it is necessary to appropriately process a variety of signals coming through several transmission paths. With respect to this point, the OFDM (Orthogonal Frequency Division Multiplexing) method is a promising technology in this technical field. In this method, data are carried on a plurality of carriers that have orthogonal relations with each other, and received signals are Fourier transformed and demodulated to provide a fade-proof communication system. This method is provided with a certain length of guard interval at each symbol, and therefore some delay signals can be limited within the guard intervals so as not to disturb the orthogonal relationship.
Ideally, all the delay signals arriving after delays from the leading wave (the first incoming wave) should be limited within the guard intervals. However some delayed signals (some path components) arrive over the guard intervals depending on the communications environment. Such signals with large delays form interference disturbing the orthogonal relationship between sub-channels, and prevent the recovery of transmitted signals. Accordingly, it is necessary to suppress such delayed signals by using adaptive equalizing techniques or adaptive array antenna techniques.
Conventional technologies for suppressing undesired delayed signals are described in "OFDM Adaptive Array for suppressing Doppler Shift", Nishikawa, Yoshitaha Hara, Shinsuke Hara, The Institute of Electronics, Information and Communication Engineering, Technical Report A-P2000-90, October 2000; "Equalizer Training Algorithms for Multi-carrier Modulation Systems" J. S. Chow, J. M. Cioffi, and J. A. C. Bingham, International Conference on Communications, pp. 761-765, 1993; and "Asymmetric Digital Subscriber Line", ITU-T Recommendation G. 992.1, 1999.
In these conventional technologies, each received and weighted signal from each of a plurality of antenna elements is converted into a digital signal, and each thus obtained digital signal is supplied to a digital processing part to adaptively adjust weighting coefficients of the antenna elements. In this method, plural digital signals each obtained from one of the adaptive array antenna elements are utilized and very accurate adaptive controlling is attained.
However, the conventional method needs to form a plurality of digital received signals based on the plurality of antenna elements. Therefore, a number of analog-to-digital converters corresponding to antenna elements are needed, the circuit is complex, and there are additional disadvantages regarding consumption of power, circuit size and cost, which are much more disadvantageous especially for small radios or mobile phones.


A photovoltaic (PV) device, comprising a PV interband cascade (IC) stage, wherein the IC PV stage comprises an absorption region with a band gap, the absorption region configured to absorb photons, an intraband transport region configured to act as a hole barrier, and an interband tunneling region configured to act as an electron barrier. An IC PV architecture for a photovoltaic device, the IC PV architecture comprising an absorption region, an intraband transport region coupled to the absorption region, and an interband tunneling region coupled to the intraband transport region and to the adjacent absorption region, wherein the absorption region, the intraband transport region, and the interband tunneling region are positioned such that electrons will flow from the absorption region to the intraband transport region to the interband tunneling region.

Photovoltaic (PV) devices, such as solar cells, are important for the conversion of solar and thermal energy into electricity. Conventional PV devices are based on semiconductor p-n junctions. For a single-junction cell with one band-gap (at a concentration of one sun), the maximum theoretical conversion efficiency is about 30%, and a current state-of-the-art efficiency of about 28% at higher concentrations (i.e. >500 suns). To achieve high conversion efficiency, multiple junction cells with different band-gap materials can be used. For example, triple-junction solar cells (containing materials with three different energy gaps) have a theoretical conversion efficiency of 56% at 1,000 suns, and a current state-of-the-art efficiency of about 32% at 1 sun and approximately 41% at 240 suns. One of the obstacles that affect practical PV device performance is a limitation in the availability of semiconductor materials with a range of bandgaps that adequately span the solar (or heat) spectrum and that can be effectively integrated within a single device or system, as well as current matching between multiple junctions.

Interband cascade (IC) photovoltaic (PV) architecture for PV devices


A lock system removably connects an earth-engaging tooth point to an adapter. The lock system is particularly suited to tooth points for large excavating buckets, such as dragline buckets. The forward-extending nose of the adapter fits within the rear-facing socket of the tooth point. Ears extend back from the tooth point on both sides of the adapter and define apertures adapted to receive pins. A hole in the adapter is also adapted to receive the pins. The pins extend through the apertures and into the hole, thus fixedly connecting the tooth point to the adapter. To remove the tooth point, both pins can be driven into the adapter hole and housed there concurrently. The tooth point can then be removed and the pins later driven out of the hole. A lock system also connects a main body pin to a rigging part. The lock system is particularly suited to large rigging parts, such as for draglines. A pair of projections extend from the rigging part and define coaxial apertures and define holes normal to, and partially intersecting the apertures. The main body pin extends between the projections and into the apertures. A pair of locking pins extend through the holes and engage slots in the main body pin. A pair of keepers releasably engage each of the locking pins. Thus, the keepers retain the locking pins in position, and the locking pins in turn retain the main body pin in position.

Removable tooth points have been used on excavating buckets and other earth moving equipment for many years. In that time several varying arrangements for retaining a tooth in place have emerged. Typically these designs attach tooth points to adapters, which in turn are attached to an excavating bucket or are otherwise secured to the earth moving device. The tooth points engage the earth to loosen it and allow the bucket to scoop it up for removal.
With large-scale excavating equipment, such as draglines, the tooth points of the bucket are subjected to substantial forces and frictional wear. Thus, tooth points wear down quickly, slowing excavation work because they cannot dig into the soil effectively, requiring greater force to do the same work and subjecting the entire excavating machine to greater stresses. In addition, without the loosening effect of the teeth, the bucket may suffer damage because of its engagement with unloosened material.
If the tooth points are replaced frequently, the excavating machine operates more efficiently. However, replacing tooth points can be a labor-intensive job, requiring costly down time for the excavating machine. Prior tooth point designs have attempted to reduce the amount of labor required to replace the points while still securely locking the tooth point to the adapter during operation. However, such designs have met with small degrees of success.
Some prior designs have used a locking pin extending vertically through the tooth point. However, in such designs, the heads of the pin are exposed to the main body of earth going into the bucket and to the earth below so that rocks often hit the heads of the pin causing deformation and dirt wedges between the pin and the receiving hole. Consequently, the pin is difficult to remove and much time is required to replace such tooth points.
Other designs have used pins that enter horizontally. However, such pins are generally difficult to replace because of the small space between teeth. Some designs have tried to remedy the problem by using two pins in the design. However, such designs still require the user to pound both pins through the width of the tooth point before removing the tooth. This is difficult because of the limited space between the teeth of the bucket.
Main body pins in large rigging parts have also been difficult to remove. A typical rigging part, such as a clevis pin must be easily removable and must be able to withstand the wear and tear associated with such parts. Past clevis parts have typically consisted of an "U"-shaped eye portion, hubs located at the end of each upright leg of the "U", and a main body pin extending between the hubs. Typically these main body pins have been secured either by a spool and wedge configuration or by welding a plate over the head of the pin. In the spool and wedge configuration, a pin is driven into a hole in the main body pin and is held in place by a compression fit. The main body pin is difficult to remove with either of these configurations. The compression-fit pins in the spool and wedge configuration have been so difficult to drive out that users have often resorted to cutting the main body pin out with a torch. The welded plate configuration also requires a torch or grinder to cut the plate off and allow the main body pin to be removed. In either case, the pins are very difficult to secure and release from the eye portion of the clevis. Similar problems have occurred with main body pins in other rigging parts such as shackles and pick-up links.

Lock system for excavating tooth point and adapter and for rigging


An asymmetric optical interferometry method, comprises the following steps: an incident light is split into two beams, and the two beams are respectively projected onto a surface of an object to be tested and a reference mirror; and then respectively pass through a first imaging lens having a larger area on the side of the object, and a second imaging lens having a smaller area on the side of the reference mirror, and overlap on a photoelectric sensor after passing through a third imaging lens to form at least one interference image (S1); the corresponding interference image is input into a computer to obtain a signal of the corresponding interference image (S2); parse the signal of the corresponding interference image to obtain a three-dimensional shape (S3) of the surface of the object. Also provide an asymmetric optical interferometry device.

In recent years, with the advancement and development of precision manufacturing technology, the technology for detecting the surface shapes of objects has been widely used. Optical interferometry makes use of interference fringes generated by two light beams to accurately measure the three-dimensional shape and structure of the surface of an object. Thanks to its characteristics of non-contact measurement and high measurement accuracy, optical interferometry is widely used to measure the fine shape structure of 3D surface of precision industrial products such as semiconductor integrated circuits, flat panel display panels (LCD, PDP, EL), and MEMS substrates. It is a key supporting technology indispensable to the field of precision machining.
With the rapid development of computer data processing and automatic control technologies, great progresses have also been made in the optical interferometry technology. The NewView8000 developed by ZYGO of United States, the BW-5500 from Nikon of Japan, and the ContourGT-K from Bruker of Germany represent the current top level of three-dimensional optical precision measuring instruments. Such a measuring instrument is characterized by nanometer-level measurement accuracy, convenient operation, and fully functional application software. However, because such a measuring instrument adopts a symmetric optical interference system and a stepping scanning method, it also has such shortcomings as low measurement speed and limited measurement area.
When an optical interference system is symmetrical, it indicates that the testing optical system is symmetrical to the reference optical system. As shown in FIG. 1, which is a schematic diagram of the structure of a symmetrical optical interference system, if it is necessary to expand the testing area, it is also necessary to expand the reference area; high precision machining and assembly techniques are required, in order to design and process a reference mirror with a large area, resulting in the higher manufacturing cost; in addition, there are only few companies around the world which can make large-area reference mirror, making it difficult to popularly used in the field of precision machining. In view of this, it is urgent to develop an optical interferometry methods that can measure a large area with low cost, portable size and easily installation.

Asymmetric optical interference measurement method and apparatus


A piezoelectric element comprises a metallic plate-shaped diaphragm, a plate-shaped piezoelectric body, and electrodes provided on both surfaces of the piezoelectric body, wherein one electrode is fixed to a main surface of the diaphragm. An extension electrode is extended onto a projection projecting from the diaphragm while it is insulated from the diaphragm. The extension electrode is extended from the diaphragm to the projection while it is insulated from the diaphragm. The extension electrode is electrically connected to the electrode which is not fixed to the diaphragm of the piezoelectric body. The piezoelectric element is attached to a case while allowing a main surface of the projection on which the extension electrode is provided to be directed outward. The case is fixed inside a housing of an electronic device, and the projection and the extension electrode are respectively electrically connected to circuit patterns of a printed circuit board mounted inside the housing by way of conductive portions provided on an elastic connection block. With such an arrangement, the case attaching the piezoelectric element thereto can be easily fixed to the electronic device and is easily connected to a circuit without trouble.

1. Field of the Invention
The present invention relates to a piezoelectric element adapted for an acoustic device such as a receiver of a telephone, etc. and a piezoelectric acoustic device using the same.
2. Prior Art
A conventional piezoelectric acoustic device comprises a case like a tray for accommodating a piezoelectric element therein, a stepped piezoelectric element support provided at an inner peripheral side of the case at the intermediate portion thereof, wherein a peripheral portion of a diaphragm is placed on and fixed to the piezoelectric element support by an adhesive. In the piezoelectric element, one of the electrodes provided on both surfaces of a plate-shaped piezoelectric body is bonded to a surface of the diaphragm wherein lead wires are respectively connected to the electrode on the piezoelectric element and the diaphragm and are extended outside the case.
Such a piezoelectric acoustic device is incorporated into an electronic device such as a portable telephone, a so-called cordless phone, and it is accommodated in a housing of the electronic device with a consideration to its interchangeability when defective, and finally fixed to the housing by screws, etc. Further, the lead wires are connected to a printed circuit board in the housing by soldering, etc.
In addition to the piezoelectric acoustic device connected by the lead wires, there is a piezoelectric acoustic device having no lead wires wherein conductive pins provided in the case contact the diaphragm and the electrodes of the piezoelectric element so as to connect to the circuit. This piezoelectric acoustic device is also accommodated in the housing of the electronic device and is fixed to the housing by screws, etc.
However, in the aforementioned piezoelectric acoustic devices, it is necessary to fix the case attaching the piezoelectric element thereto to the housing by screws, which is troublesome when incorporating the case into the housing. When exchanging the case with another case, the screws are unscrewed and removed and the another new case is fixed to the housing by screws, which is very troublesome. Further, in the piezoelectric acoustic device having the circuit therein which is connected to the piezoelectric acoustic device by lead wires, when the case having the piezoelectric element attached thereto is fixed to the housing, the lead wires must be soldered. When the piezoelectric element is exchanged for another one, the solder of the lead wires must be melted and separated from the circuit, and a new piezoelectric element must be soldered afresh. In any of the piezoelectric acoustic devices, it is very troublesome.

Piezoelectric element and piezoelectric acoustic device


A clothing managing apparatus is provided. In the clothing managing apparatus, a panel coupling protrusion (130) has a plurality of sub protrusions (131, 132) for supporting a control panel (150) in different directions, and protrusions coupling hole portion (160) receives the panel coupling protrusion (130). A holder (120) can be provided to support the control panel (150) and a top cover (100). The holder (12) includes one portion (123) coupled to the control panel (150) and the other portion (122) coupling to the top cover (100).

A clothing managing apparatus is a device that washes, dries, and regenerates clothes. Examples of the clothing managing apparatus include a washing machine, a clothes drier, and a clothes regenerating device.
Such a clothing managing apparatus includes a top cover on a top and a control panel installed on a top end of the top cover. The control panel includes various operation keys and a control unit.
In a clothing managing apparatus of the related art, a control panel includes a hook formed on a bottom front and a stopping protrusion formed on a bottom rear. The hook is formed integrally with the control panel, and the stopping protrusion is projected from an inner surface of the control panel in a -shape. A lower end of the stopping protrusion is inserted into a stopping hole defined in the top cover. The stopping hole is larger than the stopping protrusion such that the stopping protrusion can be easily inserted into the stopping hole.
The hook is caught by a predetermined portion of the top cover, and the stopping protrusion is inserted into the stopping hole, such that the control panel can be coupled to the top cover.
However, in the clothing managing apparatus of the related art, the stopping protrusion inserted in the stopping hole may wobble. Therefore, when the clothing managing apparatus vibrates during operation, the stopping protrusion wobbles continuously, resulting in damage/breakage of the stopping protrusion.
Further, since the stopping protrusion is -shaped, it is difficult to make a mold for the control panel. Furthermore, since the stopping protrusion of the control panel is formed by undercutting, the stopping protrusion cannot be easily inserted into the stopping hole due to burrs on the cut surface.
In addition, since the hook is formed integrally with the control panel, the hook may be easily damaged/broken by impacts or other reasons, and in this case, the entire control panel has to be replaced.


In order to manufacture a phase shift mask for producing a dark line pattern for semiconductor manufacturing, an opaque thin film pattern for forming a dark line is formed at a part of the boundary domain between a phase shift domain and a non-phase shift domain of a quartz substrate. Further, at a boundary portion of the phase shit domain where no opaque thin film pattern is formed, a transition portion is formed in which the etching depth stepwise chances up to 2.sup.n different depths by applying etching n times to the portion by different etching patterns at different etching depths. A phase shift mask for producing an open fine line in semiconductor manufacturing is efficiently manufactured with fewer etching steps.

Semiconductor integrated circuits have been increased in integration density, thereby improving functions and performance. Increased integration density of circuitry has been achieved by reducing pattern size, thereby forming the circuit in a smaller domain. That is, pattern size reduction has supported the semiconductor industry.
Conventionally, a photomask is employed during various photolithographic processing phases during the manufacture of the semiconductor device, serving as an original plate for transferring a fine pattern, as to a semiconductor substrate during formation of an integrated circuit. The photomask pattern is transferred at the original size or at a reduced size. The resolving dimension L of a photolithographic pattern is generally expressed as L=k1 X p /NA, wherein: p denotes an exposure wavelength; NA denotes a numerical aperture of a projective optical system; and k1 denotes a constant for a process having a value of approximately 0.5. Therefore, to form a fine pattern, it is necessary to decrease the exposure wavelength p and increase the numerical aperture NA.
In order to form a finer pattern by photolithography, the exposure wavelength has been decreased and a KrF excimer laser beam with a wavelength of 248 nm has been employed as a light source. It is known, however, that the depth of focus (DOF) for pattern transfer is generally expressed as DOF=k2 .times.p /NA.sup.2. Accordingly, the depth of focus DOF decreases as the exposure wavelength decreases. Therefore, it is possible to improve photolithographic resolution by decreasing the exposure wavelength, thereby further improving DOF.
Photolithographic performance can be improved by using the so-called ultra-resolving technique. Typically, however, deformed illumination and phase shift exposure techniques are used. The exposure technique, using the so-called Levenson phase shift mask, is considered the most promising, because the resolution and DOF can be significantly improved. The Levenson phase shift mask is a photomask for modulating phases of exposed rays passing through adjacent opaque-film apertures, creating opposite phases.
Adverting to FIGS. 19(a) and 19(b), conventional practices comprise modulating projected light employing a conventional photomask. FIG. 19(a) illustrates a sectional view of conventional photomask 200 comprising an opaque-film pattern 201 and an opaque-film aperture pattern 202. FIG. 19(b) shows the electric field amplitude after exposure through photomask 200, modulated by the aperture pattern.
FIGS. 20(a) and 20(b) show the electric field of a projected image on a semiconductor wafer on which a pattern of the photomask in FIG. 19(a) is transferred. FIG. 20(a) shows the electric field amplitude on the wafer, with an electric field 204 according to each aperture and a synthesized electric field 205. FIG. 20(b) shows the electric field intensity on the wafer. When a numerical aperture NA of an imaging system becomes less than 1, the electric field components, which change spatially and finely in the modulation information immediately behind the photomask, are removed. Further, an electric field having a moderate fluctuation is formed. The electric field modulated by adjacent apertures also has a moderate fluctuation. As a result, a synthesized electric field with considerable intensity between adjacent apertures is formed, preventing the two adjacent apertures from being separated.
FIGS. 21(a) and 21(b) illustrate how projected light is modulated by a Levenson phase shift mask. FIG. 21(a) illustrates a sectional view of a Levenson phase shift mask 300, including an opaque-film pattern 301, an opaque film aperture pattern 302 without phase shift processing, and an opaque-film aperture pattern 303 with phase shift processing. FIG. 21(b) shows the electric field amplitude immediately after exposure through Levenson phase shift mask 300. As shown in these drawings, modulation of an electric field by an opaque-film aperture is equivalent to modulation by a conventional mask. However, the electric field modulated by adjacent apertures is reversed in phase by the function of the Levenson phase shift mask.
FIGS. 22(a) and 22(b) illustrate the electric field of a projected image of a Levenson phase shift mask on a semiconductor wafer, on which a transferred pattern is formed by the Levenson phase shift mask shown in FIG. 21(a). FIG. 22(a) shows the electric field amplitude on the wafer, with an electric field 304 and a synthetic electric field 305. The image of each opaque-film aperture formed by an optical system with numerical number NA has a moderate fluctuation which is similar to a conventional mask. However, unlike the conventional mask, phases of adjacent apertures are reversed, offsetting the electric fields between the apertures. Therefore, the images of the adjacent two apertures are separately formed. Thus, high-resolution imaging results.
As shown above, the exposure resolution is improved using a Levenson phase shift mask. However, a normal Levenson phase shift mask has the following problem. When a dark pattern including a fine dark line is formed, the dark pattern is always angularly formed, and cannot be formed as an open line. In other words, the dark pattern can only be formed as a multiply-connected domain, including one or more simply-connected bright domain or domains. This occurs because the Levenson phase shift mask is formed to provide either a 0 p or a 180 p phase shift.
FIGS. 23 to 26 illustrate a conventional Levenson phase shift mask having two kinds of phases with a phase shifter formed by etching a quartz substrate. FIGS. 27 to 29 illustrate the formation of a fine dark line pattern by the above-mentioned Levenson phase shift mask.
FIG. 23 is a perspective view of a conventional phase shift mask 400, and FIG. 24 is a top view of the phase shift mask 400. FIG. 25 is a sectional view of the phase shift mask taken along line A--A in FIG. 24. FIG. 26 is a sectional view of the phase shift mask taken along the line B--B in FIG. 24.
As shown in FIGS. 23 to 26, in forming a fine dark line pattern, the opaque-film pattern 405 on quartz substrate 401 is sandwiched by opaque-film aperture patterns 402 and 403. In this case, unless the dark line connects two points on a boundary specifying the whole domain for a mask formation (i.e., unless the dark line is connecting opposite ends of a mask), at least one of the two opaque-film aperture patterns 402 and 403 is closed. In FIGS. 23 to 26, opaque-film aperture portion 403, with shifter processing, is formed as a closed pattern. Opaque-film aperture portion 402, without shifter processing, is formed to surround opaque-film aperture portion 403. Opaque-film pattern 405, corresponding to a required dark line, is formed between opaque-film aperture patterns 402 and 403.
FIGS. 27(a) and 27(b), and FIGS. 28(a) and 28(b), illustrate transmission of light applied vertically to the phase shift mask. FIG. 27(a) shows a cross section of opaque-film 405 for forming a dark line of the phase shift mask. The intensity of light passing through the cross section causes a dark line portion due to opaque-film 405, as shown in FIG. 27(b). FIG. 28(a) shows the cross section of a boundary portion of the phase shift domain of the phase shift mask. The intensity of the light passing through the cross section causes a dark line portion as shown in FIG. 28(b).
FIG. 29 shows a resist pattern formed on the positive resist on a wafer by the phase shift mask 400. A dark line image is formed on a portion corresponding to the opaque-film pattern 405, and resist pattern 406 is formed, since the positive resist is not dissolved due to development. Resist pattern 406 is formed as required, however, a dark line image is also formed at the boundary portion between opaque-film aperture patterns 402 and 403. The opaque-film pattern 405 is not present. This results because phases of the transmitted rays are reversed from each other on both sides of the boundary. Thus, a resist pattern 407 is formed on the wafer. That is, an open linear pattern is not formed but, a closed pattern including unnecessary pattern 407 is formed.
Therefore, to form a line pattern including an open line, a negative resist whose resolution is generally inferior to that of a positive resist must be used. Accordingly, adequate resolution cannot be obtained.
A method for addressing the problem in the conventional technique has been proposed in which the phase difference of the transmitted light in opaque-film apertures on both sides of a linear opaque-film pattern is 180 p. This is accomplished by changing the phase of transmitted light continuously between the apertures and, as a result, the entire domain surrounding the linear opaque-film pattern becomes a bright domain. An example of such a method is described in "Proc. SPIE 2440, p. 515", wherein portions having phase difference of 5gradations, i.e., 0 p, 45 p, 90, 135 p, and 180 p, are stepwise formed in one opaque-film aperture in order to continuously change the phase of transmitted light. Thus, a dark line image is prevented from occurring due to adjacent 0 p and 180 p portions. In this example, however, resist patterning and etching are performed four times in order to form a practically continuous phase transition portion. In this method, in order to manufacture a mask having n+1 phase gradations, resist patterning and etching must be performed n times respectively. Therefore, since many more patterning and etching steps are required, the production cost is increased, and the yield lowered.

Phase shift mask and its manufacturing method and semiconductor device and its manufacturing method using the phase shift mask


A water brake which uses mechanical power to kinetically heat water to vapor or steam, and use thereof as a steam generator or cooling water conserving dynamometer or motion retarder. In the simplest embodiment, radial impeller vanes (5b) throw water against stator vanes (6e), whence the water rebounds to the impeller (5). The peripheral rebounding movement continues back and forth. Power dissipates as heat in the water causing the water to increase in temperature and to vaporize. The vapor, being lower in density and viscosity than is the water, flows to and out a central outlet (9) while the denser water is centrifugally separated from the vapor and retained in the peripheral rebounding motion. Water leaving as vapor is continually replaced through a cooling water inlet (8), allowing continuous operation over wide ranges of speed, torque, power, and steam generation rates, both at steady state and at controlled rates of change.

There is a longstanding need in the manufacture and service of prime movers, particularly of diesel engines exceeding 250 horsepower in power output, and of heavy duty vehicles such as highway trucks and coaches, for dynamometers, or test stands, which need far less cooling water than has been required prior to the present invention.
Water brakes used as absorption dynamometers or motion retarders utilize fluid friction or momentum exchange of water, or other liquid, to dissipate mechanical power delivered from a connected power source or power transmission shaft, such as the crankshaft of an engine to be tested, an axle shaft to be slowed, or the like, through use of a rotor, operating in a bath or spray of water or other liquid within a stator. Following the first law of thermodynamics regarding conservation of energy, the power dissipated in the liquid is converted to heat within the liquid, with the liquid being heated at a rate proportional to the amount of power being dissipated.
Power, "P", is an exact function of torque "T" and rotative speed "N", and is calculated from the relation EQU P=TN/C ,
where "C" is a constant dependant upon the units of measurement used for P, T, and N.
Heretofore, the heated liquid, usually water, has been discharged as hot water while being simultaneously replaced by cold water. This is referred to as "sensible heating"; i.e., the effect can be physically sensed as a temperature increase. For fresh water density of 8.33 lb./gal. and specific heat capacity of 1 BTU/lb./F.degree., power "P" in horsepower (hp), and entering cooling water temperature "T.sub.in " and leaving temperature "T.sub.out " (both in .degree.F.), prior art cooling water flow, or consumption, rate "Q.sub.s " is, in U.S. GPM (gallons per minute): EQU Q.sub.s (P)[(42.4 BTU/min.)/hp]{1/[1 BTU/(lb.F.degree.)]}* (1 gal./8.33 lb.)[1/(T.sub.out -T.sub.in)],
which reduces to EQU Q.sub.s =5.1 * P/(T.sub.out -T.sub.in)
T.sub.out is typically 160.degree. F. and approximately 212.degree. F. maximum, while T.sub.in is typically 55.degree. F. and 32.degree. F. minimum. The 32.degree. F. and 212.degree. F. are academic extremes and are rarely if ever encountered, as cooling water that cold in the quantities required is not economically available while a leaving temperature of 212.degree. F. places a prior art water brake in danger of imminent explosion.
Substituting in and solving the above, Q.sub.s is typically 0.05, and academically at least 0.03, U.S. GPM per hp, which yields typical and minimum consumption rates of 20 GPM and 12 GPM respectively for, as an example, a 400 hp power source.
Prior art water brakes have been incapable of sustained biphase operation (i.e., with liquid and vapor in equilibrium) due to inability to separate steam from water and allow the steam to leave in quantities sufficient to avert excessive internal pressure from arising, whereas the present invention instead retains the heated water until it vaporizes and is discharged as steam. In so doing, the rate of cooling water consumption for sustained operation is greatly reduced; for the same operating conditions cited above and utilizing the 970 BTU/lb. latent heat of vaporization of fresh water, the present invention's consumption rate "IQ.sub.v ", again in U.S. GPM, is EQU Q.sub.v =(P)[142.4 BTU/min.)/hp]{1 lb./[970 BTU+(212-T.sub.in)BTU/F.degree.]}(1 gal./8.33 lb.),
which reduces to EQU Q.sub.v 5.1{P/[970+(212-T.sub.in)]}GPM
for cooling water either at or below boiling point, which further reduces to EQU Q.sub.v 0.005*P GPM
for cooling water at its boiling point.
Substitution and solving yields present invention cooling water consumption rates of 0.0045 GPM per hp for 55.degree. F. cooling water, and 0.005 GPM per hp for 212.degree. F. cooling water; only 2 GPM for the 400 hp example above, or an order of magnitude (90%) less than the prior art, sensible heat water brake.
Additionally, the present invention can readily utilize cooling water entering at any temperature up to the boiling point while prior art waterbrakes typically require a large temperature difference between cold water entering and hot water leaving, and must be derated in capacity if this temperature difference is not available.
To accommodate differing and varying torque inputs in most applications, water brake retarders and, especially, dynamometers must have an adjustment or control capability; i.e., the amount of torque load they present their power sources must be controllable. In water brakes, this is most commonly done by adjusting the amount of water contained within the apparatus's housing and therefore in motion between rotor and stator. Operation must, in some applications, be controllably rangeable over a ratio of 50 to 1 in torque load.
The present invention belongs also to another class of invention, the mechanical liquid vaporizer. There are other mechanical liquid vaporizers in the prior art, but none are known to the applicant to be useable in sustained commercial operation as a retarder or dynamometer without disadvantage or deficiency as described immediately below and, in many cases, without addition of a heat transfer fluid loop. Only mechanical liquid vaporizers driven by moving shafts, whether rotatitive or linear, are considered herein; those utilizing electrical discharges, refrigerants, gasses, and the like are outside the scope of the present invention.
U.S. Pat. No. 3,198,191 (Wyszomirski, 1965), represented, specified, and claimed only as a heat generator, was, like the present invention, also a tangential water brake. Its squirrel cage impeller blades, however, by their very nature being not of full radial depth, precluded large adjustability of amount of water being impacted by the vanes or blades and therefore could not provide sufficient rangeability of torque load for general use as a retarder or dynamometer. Additionally, the squirrel cage blades and unobstructed inner chamber within the inner diameter of those blades allowed steam egress but did nothing to separate, remove, and recirculate particles of water entrained in the rapidly flowing steam, resulting in undesireably wetter steam at low operating speeds. Moreover, the construction of this device necessitated use of a relatively complex steam discharge tube assembly comprising inner and outer tubes, bearing, seal, leakage drain hole, and closely machined fits.
U.S. Pat. No. 1,149,938 (Naglevoort, 1915) was a tangential water brake but did not vaporize its cooling water.
U.S. Pat. No. 14,277,020 (Grenier, 1979) was a water brake of the viscous shear type and was intended primarily to heat liquid in a two-loop heat exchange system, but could also vaporize the liquid within the water brake. It was not, however, adjustable in torque load, and lacked means of discharging safely large quantities of steam and of separating entrained water particles from the steam.
U.S. Pat. No. 2,344,075 (Beldimano, 1944) was also a water brake and also used a heat transfer loop, in this case a water jacket surrounding the oil-filled water" brake. No steam generation or controllability were referred to.
U.S. Pat. No. 3,791,349 (Schaefer, 1974) was a steam generator, but not adjustable in torque load. Additionally, it utilized rapidly repeated water hammer, or fluid shock, within closed tortuous passageways; such phenomena are not normally regarded as conducive to long and troublefree life.
U.S. Pat. No. 4,781,151 (Wolpert et al., 1988) and U.S. Pat. No. 4,271,790 (Ahmed et al., 1981) were other embodiments of water brakes, neither adjustable in torque load and both utilizing two-loop heat transfer circuits.
U.S. Pat. No. 4,115,027 (Thomas, 1978) and U.S. Pat. No. 5,003,829 (DeConti and Quenneville, 1991) are representative of water cooled mechanical friction brakes (typically of drum, disk, or band styles), which can generate steam and are responsive to control actions over large ranges of operation. Under sustained heavy load, however, they require frequent replacement of sacrificial wear pads or blocks, and are prone to rotor failure caused by heat distortion and material heat checking. Depending upon aggressiveness of friction material selected, which must be carefully balanced with other factors including wear rate of friction pad material, they can also chatter or become unstable in torque load, particularly at very light or heavy load levels.
The above are representative of prior art waterbrakes which do not vaporize their cooling water (or other fluid) and hence require relatively large coolant flow rates, and of mechanical liquid vaporizers which lack the appropriate attributes of a water brake to an extent sufficient to preclude extended or sustained use as retarders or dynamometers.
The present invention is therefore a novel and very useful solution to prior art limitations in that it is a water brake which requires little cooling water and which discharges steam, instead of hot water, as either end product or byproduct, as the user wishes, and therefore can be used as steam generator, motion retarder, or dynamometer, either individually or simultaneously in combination. It generates steam with an efficiency of very nearly 100% since, except for minor radiation and convection losses from the apparatus's housing (which can themselves be made even smaller by covering the housing with thermal insulation), power entering through the shaft is all converted to thermal energy in the heating and vaporizing of water. Testing has shown it to be stable in speed and in torque load imposed upon a prime mover. Further, it's of simple design, easily manufactured and suitable for robust construction, and operates equally well in any angle of orientation, i.e., with shaft horizontal, vertical,,or any angle between.


In a device or in a method for oscillometric measurement of the blood pressure, the pulse time differences are determined associated with the measurement of the blood pressure. Subsequent pulse time differences are stored in a storing unit (15). A distribution of pulse time differences is calculated in a calculating unit (16) and compared in a comparing unit (17) with predetermined reference values. If the distribution or the values of pulse time differences exceed a predetermined amount, an indication means (19) is activated which indicates existence of arrhythmic activities.

The invention relates to a method and a device for the non-invasive measurement of the blood pressure and for simultaneous detection of arrhythmia.
The clinical standard of measuring the arterial blood pressure is the auscultation of audible sounds during the release of an inflated cuff in the cubital region of the brachial artery. The method is called the Riva/Rocci method by analysis of the so-called Korotkoff pulse sounds. First, non-invasive blood pressure measuring devices automatically recorded the Korotkoff sounds by the integration of a microphone into the cuff design. Although these devices proved to be very accurate, the critical microphone positioning and the occurrence of artefact sounds limited the clinical use of this method. Detection of arrhythmia proves to be an important parameter for prevention of cardiac diseases. It is known in the art to determine arrhythmic activities by means of an electrocardiographic method. Since both arrhythmia and chronic hypertension is associated with a severe risk in establishing cardiovascular diseases such as arteriosclerosis and cerebral ischaemia, it is known to simultaneously measure the blood pressure of the patient and to detect arrhythmic activities by the use of an electrocardiogram.
From U.S. Pat. No. 4,262,674 it is known, to simultaneously measure the blood pressure based on Korotkoff sounds and to determine time differences between two consecutive pulses. The method according to this US patent is difficult to carry out because of the mentioned critical microphone positioning and the occurrence of artefact sounds. Further, the method according to the US patent is based on a strict consecutive treatment of measured pulses. The procedure does not analyse the total pulse pattern during the measuring time.
The oscillometric non invasive measurement of the arterial blood pressure has been clinically introduced at the beginning of the 1980s. The technology required a pneumatic pressure pulse detecting system and a microcomputer based signal analysis. Due to the fast technological progress on semiconductors, the devices were consequently equipped with smaller but more powerful microcomputers, programs and memories. In that way, the accuracy and stability of the non-invasive arterial blood pressure measurement was gradually improved.
The oscillometric method does not detect pulse sounds, but pressure changes within the cuff during the deflation process. The pressure pulses are generated by small amounts of streaming blood passing the vessels under the partially inflated cuff. Oscillometric devices avoid the use of a microphone and just require the application of a cuff at the patient""s application site. For that reason, this technology was not only widely introduced clinically but was further integrated within a growing number of small blood pressure measuring devices, built for home use application.
Non-invasive oscillometric arterial blood pressure measuring units for home use were introduced widely towards the end of the 1980s. These devices measure and display three values: the arterial systolic pressure, the arterial diastolic pressure and finally the pulse frequency; all parameters are derived from the cuff application site.
The medical relevance of these devices is high. They are used in persons for whom regular measurements are recommended as a preventative measure, as well as in patients undergoing hypertensive or hypotensive blood pressure treatment. Since the age-dependent prevalence of hypertension is very high within the industrialised countries, regular blood pressure measurement serves as a crucial diagnosis measure to supplement the physician""s diagnostic results.
As chronic hypertension is associated with a severe risk in establishing certain cardiovascular diseases, e.g. arteriosclerosis and cerebral ischaemia, a physiological adjustment of the arterial blood pressurexe2x80x94especially the diastolic arterial blood pressurexe2x80x94has been recognised as a highly efficient risk reduction of such disorders.
Further, a broad range of cardiac and extra-cardiac diseases are accompanied by rhythm disorders of the heart. This applies e.g. for diseases of the coronary arteries, diseases of the myocardial muscle, and disorders of the heart""s excitation. In some cases, arrhythmia are significant early symptoms indicating the increased risk of developing certain severe heart malfunctions.
Some relevant arrhythmic heart activities are characterised by pathological variations of peripheral pressure pulse curves. So, pressure pulse curves may be used to identify certain arrhythmic events of the heart. Since pressure pulsations are monitored in the course of the oscillometric measurement, the analysis of the pulse pattern may be used to identify arrhythmic events. The analysis of the pulse rhythm is based on the analysis of pulse time difference, which is the time span between two correspondent pulse characteristics.
In case of a pathological rhythm status, pulse time differences may vary significantly in the course of the NIBP (xe2x80x9cnon-invasive blood pressurexe2x80x9d) measurement, or may be basically beyond physiological ranges. That means pulse time differences either change significantly or prove to be too high or too low. This is the basis of the detection of clinical relevant arrhythmia activities:
Supraventricular premature contractions: variation high due to pulse loss
Ventricular premature contractions: variation high due to pulse loss
Atrial fibrillation variation high due to absolute arrhythmia
Paroxysmal supraventricular tachycardia mean time difference low
Sinus-Tachycardia mean time difference low
Sinus-Bradycardia mean time difference high
Ventricular Bradycardia mean time difference high
Some arrhythmic activities are unfortunately not noticed by patients, since the associated symptoms remain minimal. However, certain types indicate a severe forthcoming heart malfunction. For this reason, early diagnosis and therapy may diminish the risk of serious complications.
Arrhythmia are very common within the population of industrialised countries. For example about 0.5% of all adults, 3% of all people aged over 60, and 15% of all people over 70 suffer from atrial fibrillation.
It is an object of the present invention to overcome the drawbacks of the prior art, especially to provide a device and a method for simultaneously measuring blood pressure and detecting arrhythmic activities, which are both reliable and easy to apply, which are adapted for home use and which are easy to manufacture and carry out.
According to the present invention, these objects are solved with a method and a device according to the independent patent claims.
According to the invention, a pulse distribution is measured and is analysed by the device. The pulse distribution is investigated by using known medical criteria representing physiological or pathophysiological conditions, which are stored within the device. These criteria decide whether there is reason to diagnose an arrhythmic activity in the course of the NIBP measurement. Transformation, calculation and comparison can be effected analogically, digitally or by direct EDP comparison of curves. There can be signal storage and batchwise processing or on-line processing.
According to the method of the present invention, the blood pressure is preferably measured by measuring the pressure pulses of the blood in an artery by oscillometric measurement techniques. Measurement and analysis of the pressure pulses by oscillometric techniques allows the calculation of the blood pressure, especially the systolic and diastolic pressures. In order to indicate an arrhythmia, all values of the time difference between consecutive pulses are determined. The values of a plurality of consecutive pulse time differences are stored in a storing unit. The distribution of the pulse time differences is subsequently calculated in a calculating unit. In order to determine the existence of arrhythmic activities, the values and the distribution of the pulse time differences are compared with predetermined reference values and predetermined reference distributions of the pulse time differences in a comparing unit. In order to indicate the existence of arrhythmic activities, the comparing unit is caused to generate a signal if the values and/or distributions of the pulse time differences on the one hand and the predetermined arrhythmic specific values and distributions on the other hand are sufficiently close to each other. The signal can be optical, acoustic or any other kind of signal.
The method according to the invention is intended for a broad range of medical use. This includes the clinical application, the emergency based application, as well as home use. The indication of existence of arrhythmic activities tells the patient to consult a physician for a more detailed cardiac diagnosis.
The pressure pulse signals acquired by the oscillometric measurement are preferably amplified in a pulse pressure amplifier which generates an amplified signal. The amplified signal can subsequently be filtered and converted into a digital signal with an analogue/digital converter. Amplification and A/D conversion is known to those skilled in the art and is not the object of the present invention.
In a preferred embodiment, a pulse time difference histogram is generated in the calculating unit. Representation of the pulse time difference distribution in a histogram allows an especially reliable and precise detection of tie existence of arrhythmic activities.
The device according to the present invention substantially comprises a blood pressure monitor for indicating the blood pressure values and a cuff for the non-invasive oscillographic measurement of the blood pressure. The cuff is connected to the blood pressure monitor. A time difference measuring unit is used to determine the values of time pulse differences between two consecutive pulses. The device further comprises a storing unit for storing a plurality of consecutive time pulse differences which have been determined by the time difference measuring unit. The device is further provided with a calculating unit for calculating a statistic distribution of the time pulse differences and a comparing unit for comparing the values and the statistic distribution of the time pulse differences with predetermined reference values and reference distributions. The comparing unit is adapted to create a signal when the value and/or the distribution of the time pulse differences on the one hand and the predetermined value or reference distribution representing pathophysiological conditions on the other hand are sufficiently close to each other. It is also conceivable to create a signal if the difference between the measured parameters and criteria representing physiological values exceeds a certain amount.
The device comprises preferably a pulse pressure amplifier which creates an amplified pulse signal. The device further comprises a signal filter and optionally an A/D converter which filters and converts the amplified signal into a digital signal. The calculating unit is adapted to calculate a pulse time difference histogram. Such calculating units are known to those skilled in the art and are not the object of the present invention.
The device is preferably provided with indication means for indicating the existence of arrhythmia. Any kind of known indication means are possiblexe2x80x94preferably, for instance, signal lamps, LEDs or an LCD display. It is also conceivable to provide acoustic indication means.
The apparatus detects arrhythmic activities during the non-invasive measurement of the arterial blood pressure. The apparatus uses a cuff which is wrapped around the patient""s upper leg, lower leg, toe, upper arm, forearm or finger. After inflation of the cuff, the pressure is released gradually in order to measure arterial pulses by detecting pressure pulses. An inbuilt memory stores the pulse amplitudes of each pulse, the associated cuff pressure and the time differences between two consecutive pulses. While the first and second parameters are used to determine the systolic, mean and diastolic arterial blood pressure, the third parameter is applied in order to detect arrhythmic pulse activities of the patient. The detection includes premature ventricular and supraventricular contractions, absolute arrhythmia as well as tachycardia and bradycardia. The apparatus displays the result of the rhythmic analysis and indicates the user to take actions according to the result.
The analysis of the pulse time difference within a oscillometric measurement discloses the mean pulse time difference and the scattering of pulse time differences within one complete measurement cycle. Therefore the pulse time differences are investigated for every full measurement in order to detect possible arrhythmic activities.
The present invention analyses the pulse time difference signals derived from pulses within the pulse oscillogram. The analysis result is displayed beside the conventional values.

Method and a device for non-invasive measurement of the blood pressure and for detection of arrhythmia


An inter-vertebral cage for use in repairing a damaged inter-vertebral disc includes a plurality of cage sections and a hinge element that connects adjacent ones of the cage sections together for relative movement. The hinge elements automatically urge the cage sections to move from an extended orientation to an installed orientation.

This invention relates in general to the treatment of diseases of the spine using inter-vertebral devices and implantation methods. In particular, this invention relates to an automatically self-expanding inter-vertebral cage that can enter into a cavity through a small opening and automatically acquire any desired form as a result of being either released from an installation tool or from being exposed to environmental conditions, such as temperature, moisture, light, magnetic field, electric field, pressure, etc. (or the lack thereof). More particularly, the self-expanding inter-vertebral cage of this invention can utilize shape memory alloy materials to accomplish the automatic activation.
One of the most common causes for disability in people aged forty-five to sixty-five is pain in the lower back. Often, this is caused by compression of an inter-vertebral disc, which creates pressure on nerves extending from the spinal cord. Decompression spinal fusion procedures (also called inter-body fusion) are an effective means to reduce and, in some cases, eliminate numbness, weakness, and pain stemming from numerous medical conditions including, but not limited to, disc degeneration, spondylolisthesis, and disc herniation. There are also other causes of back pain, such as facet joint arthrosis, slipping of one vertebrae over another, deformity, and the like.
In cases of chronic back pain or weakness, spinal fusion procedures are usually recommended as a last resort. Procedures such as these share a relatively high risk of injury that coincides with the rewards of decompression of nerves and relief from debilitating pain. Thus, it is usually suggested that conservative management procedures, such as physical therapy, non-steroidal anti-inflammatory drugs, pain management, and muscle relaxing drugs be attempted and proven to unsuccessful in the treatment of the pain for at least six months before any surgical procedure is performed.
Although decompression spinal fusion procedures often succeed in removing the nerve pain, the pain related to instability between the two vertebrae often requires stabilization of the vertebrae level. Because the highest levels of stress and degradation of inter-vertebral bodies occurs in the lower (or "lumbar") spine, this area is the focus of most fusion procedures, including posterior lumbar interbody fusion (PLIF), anterior lumbar interbody fusion (ALIF), transforaminal lumbar interbody fusion (TLIF), far lateral lumbar interbody fusion (FLLIF), and, more recently, extreme lateral interbody fusion (XLIF). The names of these surgical procedures denote the anatomical direction from which they are inserted. Each of these procedural approaches for implanting interbody fusion devices has its own set of advantages and disadvantages. As will be explained in greater detail below, this invention can be practiced using any of these techniques, as well as other techniques, in particular minimally invasive techniques.
A typical lumbar fusion device ranges in height from 10 mm to 20 mm based upon which motion segment is to be fused, as well as patient-specific measurements. The PLIF is one of the most flexible procedures, being able to access all lumbar and sacral motion segments. However, it is also one of the most dangerous procedures because of its close proximity to the spinal cord. Because of that, it has been determined that a minimally invasive device and procedure would be best suited for application in this surgical approach. The self-expanding inter-vertebral cage described and illustrated herein requires a much smaller incision compared to existing full-sized cages, which allows the cage to be elongated prior to insertion. As a result, the cage of this invention can be installed through a much smaller incision than previously available, an incision having a size that is approximately equal to a width of the elongated cage.

Expandable inter-vertebral cage and method of installing same