Abstract: A device (1) for measuring the strike velocity of a game ball struck by a striking element, particularly a tennis racket (2), said device being provided directly on the racket. The device comprises at least one measuring sensor mounted on the strings (4) of the racket (2) and arranged to output signals for the strength of the vibrations generated by the ball, means for processing said signals using microprocessors that analyse the signals and determine a measured value of the ball velocity, and means (6) for displaying said value. The processing means comprise a calibrating unit for automatically correcting the measured value depending on at least the features of the racket and the ball in order to provide a highly accurate and reliable result. Said measuring device is miniaturised and inexpensive and fits in a small housing (3) mounted on the racket (2) to enable the player to read the velocity value directly.

Abstract: A semiconductor pressure detecting device which effectively reduces stress that occurs on a base member due to welding between cap and the base member or any external load. The semiconductor pressure detecting device includes a semiconductor sensor element capable of detecting a strain and/or stress that occurs on a thin-walled pressure receiving portion; a pedestal seat for joining and supporting the semiconductor sensor element; a base member for joining and supporting the pedestal seat; and a cap member welded and joined to the base member so as to cover the base member, the pedestal seat and the semiconductor sensor element.

Abstract: The present invention relates to methods for determining the uniformity of the piezoelectric effect throughout a piezoelectric material using the time-of-flight of an acoustic wave through the material as a gauge of that uniformity.

Abstract: A sensor element provided with a silicon substrate having a semiconductor circuit, a sensing-element portion formed on the silicon substrate and connected to the semiconductor circuit, and a cavity portion formed by removing a silicon substrate portion below the sensing-element portion, in which a removal resistance region having resistance against substrate removal is provided in the silicon substrate between the semiconductor circuit and the cavity portion.

Abstract: A micromechanical device or microactuator based upon the piezoelectric, pyroelectric, and electrostrictive properties of ferroelectric thin film ceramic materials such as PZT. The microdevice has a device substrate and a deflectable component. The deflectable component is mounted for deflection on the device substrate and has a sensor/actuator. The sensor/actuator has first and second electrodes and a piezoelectric thin film disposed between the first and second electrodes. The thin film is preferably PZT. The sensor/actuator is disposed on a sensor/actuator substrate. The sensor/actuator substrate is formed of a material selected for being resistive to attack by hydrofluoric acid vapor. The invention also relates to a method for fabricating such micromechanical devices or microactuators.

Abstract: A quartz crystal resonator is excited in two different modes at the same time such that the mass change and the temperature change can be measured independently. In using such a quartz crystal the change in mass can be calculated accurately and in real time, independent of temperature effects.

Abstract: A device and method for detecting microorganisms in a specimen by culturing the specimen in a sealable specimen container with a culture medium and detecting microorganisms in the specimen by measuring changes in pressure within the container caused by their metabolic activity during culturing. Pressure changes are measured using a sensor having a deformable section in communication with the container and a piezoelectric apparatus, such that the piezoelectric apparatus is deformed by changes in pressure within the specimen container and an electrical signal is produced by the deformation. The electrical signal is processed to detect any change in the rate of change of pressure, and thus detect the growth of microorganisms.

Abstract: A piezoelectric pressure sensor for detecting pressure in a combustion chamber of an internal combustion engine includes a backing plate secured within a housing. The sensor also includes a resilient prestress plate stacked on the backing plate. The resilient plate is formed of silicone elastomer. A sensor element is stacked on the resilient plate. The sensor element is composed of a piezoelectric material formed from a mixture of lead titanate and lead zirconate. A thermally insulating plate is stacked on the sensor element and a diaphragm plate is stacked on the thermally insulating plate and also secured to the housing. The diaphragm plate is exposed to combustion atmosphere and is adapted to transmit a pressure being determined onto the sensor element.

Abstract: A force measuring device for measuring forces between mutually parallel machine parts, preferably in force bypass. The device has two mutually parallel abutment faces (5,6) having an adjustable distance between them. A force sensor (18) is integrated in a first measuring wedge (1), with a first measuring face projecting beyond the measuring wedge (1) and forming the first abutment face (5). On the side opposite the abutment face (5) is a first force-transmitting inclined slide face (15). A second measuring wedge (3) comprises a second force-transmitting slide face (16) being parallel to the first slide face (15). On the side opposite the second slide face (15) is the second abutment face (6) being parallel to the first abutment face (5). The measuring wedges (1,3) can slide relative to each other on the slide faces (15,16) thereby causing the abutment faces (5,6) to move parallel to each other. The wedges (1,3) are connected to each other by an adjustment device (7,8).

Abstract: A low cost, high bandwidth "smart skin" impact sensor is developed for application to vehicle side impact detection and diagnostics. The sensor is based on a piezo polymer smart skin technology and can sense impact location and impact energy in real time (i.e., fractions of a millisecond) along a vehicle side panel. The sensor is simple to manufacture, is low cost in production quantities, and can be used in concert with other devices in a sensor suite to provide, reliable, efficient, energy managed airbag development. With proper spatial shading techniques it is shown that the sensor can be designed also to report impact angle and the velocity of the impacting body.

Abstract: Process for the production of accelerometers using the silicon on insulator method. The process comprises the following stages: a) producing a conductive monocrystalline silicon film on a silicon substrate and separated from the latter by an insulating layer; b) etching the silicon film and the insulating layer up to the substrate in order to fix the shape of the mobile elements and the measuring device; c) producing electric contacts for the measuring devices; d) partial elimination of the insulating layer in order to free the mobile elements, the remainder of the insulating layer rendering integral the substrate and the moving elements.

Abstract: The periphery of a disk having flexibility is fixed to a sensor casing, and a force applied to the central portion is detected. A doughnut disk-shaped piezoelectric element is positioned on the upper surface of the disk, and upper electrode layers indicated by patterns of D1 to D6 are formed on the upper surface of the piezoelectric element. Further, lower electrode layers similarly having pattern of D1 to D6 are formed on the lower surface of the piezoelectric element, and the lower surface of the lower electrode layer is fixed on the upper surface of the disk. Six detection elements D1 to D6 are formed each of which is constituted by a pair of upper and lower electrode layers and a portion of piezoelectric element put therebetween. Thus, force components exerted at an origin defined in the central portion of the disk in respective axes directions of X, Y, Z can be detected based on charges produced in detection elements D1, D2, detection elements D3, D4, and detection elements D5, D6, respectively.

Abstract: A pressure/force transducer having a sensor body with a load-receiving member at one end, a load button positioned within the sensor body and having a curved surface in surface-to-surface continuous contact with the load-receiving member, a piezoelectric plate positioned within the sensor body and in contact with the load button, and a signal processor for converting the electrical charge produced by the piezoelectric plate into a humanly perceivable signal. A preloading member is connected to the sensor body so as to adjustably force the load button into surface-to-surface contact with the load-receiving member. The load-receiving member is integrally formed with the sensor body. This load-receiving member has a radiused corner connecting the member to the sensor body. The load button is a generally cylindrical member with a generally curved surface in contact with the load-receiving member.

Abstract: A semiconductor substrate has a surface layer disposed underneath a gate electrode of a field-effect transistor and having a resistance higher than the resistance of an inner layer which is formed in the semiconductor substrate below the surface layer. The surface layer is formed when a donor doped in the surface layer and an acceptor generated based on a compressive stress which is developed in the surface layer when the gate electrode is formed substantially cancel out each other. The field-effect transistor operates alternatively as a junction field-effect transistor when the surface layer is turned into a p-type structure when a compressive stress is generated in the surface layer and a metal semiconductor field-effect transistor when the surface layer is turned into an n-type structure when a tensile stress is generated in the surface layer.

Abstract: A training system for monitoring kinetic activities of an individual uses one or more transducers that are highly directionally sensitive to detect certain characteristics of a user's activity, such as motion, direction of motion, distance, velocity, and the like. The sensors have a housing which includes an acceleration-responsive transducer and circuitry responsive to output signals from the transducer to provide an indication to the user of certain characteristics of the activity. In a preferred embodiment, the sensor has a pointer indicating the direction of maximum sensitivity of the transducer, so that the user can orient it to preferentially detect motion in certain directions. The output signal supplied to the user preferably comprises a tone having one of several discrete frequencies corresponding to discrete range intervals of the transducer output.

Abstract: A vibration sensing apparatus including an acceleration sensor 2 for outputting a sensing signal corresponding to a vibrating acceleration, a level discriminator 3 for generating an output when the output level of the signal from the acceleration sensor 2 exceeds a preset reference level, a display unit 4 for displaying the output of the level discriminator 3, a piezoelectric ceramic power generating unit 5 using piezoelectric ceramics for generating a charge when it is subjected to vibration, and a conversion unit 6 for converting the charge generated by the piezoelectric ceramic power generating unit 5 into DC power, the DC power being supplied to the level discriminator and to the display unit as power to be consumed by them.

Abstract: The periphery of a disk having flexibility is fixed to a sensor casing, and a force applied to the central portion is detected. A doughnut disk-shaped piezoelectric element is positioned on the upper surface of the disk, and upper electrode layers indicated by patterns of D1 to D6 are formed on the upper surface of the piezoelectric element. Further, lower electrode layers similarly having pattern of D1 to D6 are formed on the lower surface of the piezoelectric element, and the lower surface of the lower electrode layer is fixed on the upper surface of the disk. Six detection elements D1 to D6 are formed each of which is constituted by a of upper and lower electrode layers and a portion of piezoelectric element put therebetween. Thus, force components exerted at an origin defined in the central portion of the disk in respective axes directions of X, Y, Z can be detected based on charges produced in detection elements D1, D2, detection elements D3, D4, and detection elements D5, D6, respectively.

Abstract: A semiconductor-on-insulator structure includes a single crystal semiconductor substrate, an insulating layer on the single crystal semiconductor substrate, a recrystallized single crystal semiconductor layer on the insulating layer and having a subgrain, i.e., quasi grain boundary and a highly doped region including the quasi grain boundary and having a higher dopant impurity concentration than other parts of the single crystal semiconductor layer. Thus, a non-uniformity in the resistance is suppressed without reducing the piezoresistance effect of the structure.

Abstract: An integrated microfabricated instrument for manipulation, reaction and detection of microliter to picoliter samples. The instrument is suited for biochemical reactions, particularly DNA-based reactions such as the polymerase chain reaction, that require thermal cycling since the inherently small size of the instrument facilitates rapid cycle times. The integrated nature of the instrument provides accurate, contamination-free processing. The instrument may include reagent reservoirs, agitators and mixers, heaters, pumps, and optical or electromechanical sensors. Ultrasonic Lamb-wave devices may be used as sensors, pumps and agitators.

Abstract: An electrode layer is formed on the upper surface of a first substrate, and a processing for partially removing the substrate is carried out in order to allow the substrate to have flexibility. To the lower surface of the first substrate, a second substrate is connected. Then, by cutting the second substrate, a working body and a pedestal are formed. On the other hand, a groove is formed on a third substrate. An electrode layer is formed on the bottom surface of the groove. The third substrate is connected to the first substrate so that both the electrodes face to each other with a predetermined spacing therebetween. Finally, the first, second and third substrates are cut off every respective unit regions to form independent sensors, respectively. When an acceleration is exerted on the working body, the first substrate bends. As a result, the distance between both the electrodes changes. Thus, an acceleration exerted is detected by changes in an electrostatic capacitance between both the electrodes.

Abstract: A less expensive small semiconductor pressure sensor in which a pressure sensing element is not displaced by vibration and the like and wire bonding is highly reliably effected includes a pressure sensing element having a diaphragm and a glass base die bonded to a die pad in substantially the same plane as that of an outer lead with a bonding resin. Each of two sets of hanging leads is attached to one of two opposite sides of the die pad to fix the die pad to a package base. With this arrangement, the die pad is securely bonded to the package base to prevent breakage of a metal wire caused by vibration and the like so that a less expensive and smaller semiconductor pressure sensor can be provided.

Abstract: A force sensor employing a silicon chip having a force application area on a top surface and attached to a support at a bottom surface. Piezoresistive elements are arranged on the silicon chip in areas of high mechanical tension and produce signals. Circuits, which receive the signals produced by the piezoresistive elements, are arranged on the silicon chip in areas of low mechanical tension. The areas of mechanical tension may be influenced by providing grooves and/or recesses in the bottom surface of the silicon chip and by providing grooves in the top surface of the silicon chip.

Abstract: A pressure sensor assembly including semiconductor transducer elements disposed upon a diaphragm support structure, wherein the support structure is comprised of a plurality of substrate layers anodically bonded together. A groove is disposed in the support structure creating an area of reduced thickness within the support structure. The ares of reduced thickness acts as a stress concentration region. As such, the transducer elements are disposed within the ares of reduced thickness so as to efficiently monitor any deformations experienced by the support structure. The groove that creates the ares of reduced thickness is formed in each of the substrate layers, prior to bonding into the overall structure, as such a very accurately tolerance groove can be formed into the structure which greatly increases the reliability of the structure.

Abstract: A method of, and apparatus for, measuring dynamic torque transmitted by a shaft having an axis of rotation is characterised by the steps of:1 locating on the shaft (S) a pair of transducers (T, T1, T2), each comprising an SAW resonator, as a complementary pair so that for a first direction of rotation (K) of the shaft (S) about the axis (A) one transducer (T1) is under compression and the other (T2) in tension and for a reverse direction of rotation of the shaft the one transducer (T1) is in tension and the other (T2) in compression, a signal input (C1) and a signal output (C2, C3) for either each transducer or a single signal output for a signal derived from both transducers, the signal input and signal output or outputs being located at discrete locations on or near the outside of the shaft (S) for rotation therewith,2 causing a driving signal to be applied to the signal input (C1);3 detecting at each or the signal outlet (C2, C3) at least an output resonant frequency of the transducer (T, T1, T2) when driv

Abstract: Disclosed is a method and apparatus for sensing the vibrational response of a slider of predetermined dimensions during contact with one or more surface asperities on a recording surface, separating the response into its individual bending mode frequency component responses, determining one or more bending mode frequency responses which display monotonic behavior with increasing asperity interference, and designing a mode selection sensor optimized to detect the monotonic bending mode frequency identified. The mode enhanced sensor is designed by first analyzing the stress distribution of the slider corresponding to the monotonic bending mode frequency, identifying regions of the slider which experience substantially positive or substantially negative stress, and partitioning the upper conductive layer of a piezoelectric sensor to form a partitions corresponding to each of the identified regions. The sensor may be further enhanced by tailoring the partitions to exclude undesirable stress contributions.

Abstract: A piezoelectric liquid level switch is provided which can be made immune to standing wave effects and provides an unequivocal response to liquid contact.

Abstract: The periphery of a disk having flexibility is fixed to a sensor casing, and a force applied to the central portion is detected. A doughnut disk-shaped piezoelectric element is positioned on the upper surface of the disk, and upper electrode layers indicated by patterns of D1 to D6 are formed on the upper surface of the piezoelectric element. Further, lower electrode layers similarly having pattern of D1 to D6 are formed on the lower surface of the piezoelectric element, and the lower surface of the lower electrode layer is fixed on the upper surface of the disk. Six detection elements D1 to D6 are formed each of which is constituted by a pair of upper and lower electrode layers and a portion of piezoelectric element put therebetween. Thus, force component s exerted at an origin defined in the central portion of the disk in respective axes directions of X, Y, Z can be detected based on charges produced in detection elements D1, D2, detection elements D3, D4, and detection elements D5, D6, respectively.

Abstract: Thin, planar sensors for measuring forces exerted by mattresses or chair pads on a patient's body include a central conductive elastomeric pad movable in a horizontal plane into more or less intimate contact with flexible peripheral conductors adjacent the central pad, thus varying electrical conductivity between the central pad and peripheral conductors by a surface piezoresistive effect proportional to the magnitude and direction of horizontal shear forces exerted on the pad. The preferred embodiment comprises a matrix area array of thin, square central conductive elastomeric pads, each surrounded by four square peripheral conductive elastomeric pads forming a close pack tiling arrangement that utilizes inner peripheral conductors in the array to function as one of the peripheral conductors for two or three nearest-neighbor sensors.

Abstract: A magnet position detector, particularly for implantable medical devices, has a resiliently supported coil, a current source delivering a current to the coil and a detecting device for detecting the movement of the coil in a magnetic field when fed with an electric current from the current source. The coil has a core with a non-linear B-H curve and the current source is a pulse source delivering current pulses with at least one positive and one negative side. The detecting device detects the movements of the coil in opposite directions respectively excited by differentiated signals respectively corresponding to the leading and trailing edges and permits the magnitudes of the respective, oppositely directed movements to be compared to each other, thereby indicating the position of a source of the magnetic field, relative to the coil, to be determined.

Abstract: An electromechanical transducer is provided, and the process for making it utilizes a piezoresistive element or gage which is dielectrically isolated from a gap spanning member and substrate upon which it is supported. The gage of the invention is a force gage and is derived from a sacrificial wafer by a series of etching and bonding steps which ultimately provide a gage with substantially reduced strain energy requirements.

Abstract: A generally tubular flexure sensor is constituted by winding a piezoelectric element including a polymeric piezoelectric strip provided with oppositely disposed surface electrode layers on both surfaces around a central axis (helical axis) so that the surface electrode layers are disposed substantially in parallel with an extension direction of the helical axis, and combining the helically wound piezoelectric element with a detection circuit for detecting a flexural deformation of the piezoelectric element in a direction perpendicular to the helical axis. The flexure sensor allows a large degree of flexural deformation in any direction to provides a good sensitivity and can be suitably used as a fish catch signal sensor for a fishing rod.

Abstract: The invention comprises a force measuring system and an assembly procedure for the dynamic determination especially of axle loads, speed, as well as for assembly of force and acceleration sensors. The force measuring system can be laid permanently in the roadway. It is of modular assembly, consisting of the amplifier, sensor and terminal module. The sensor module consists of a hollow section, in which piezo-elements are fitted under elastic preload. The hollow section is designed so that it can be opened elastically by lateral clamping, to allow mechanically interconnected piezo-elements to be inserted simply. After releasing this clamping, the piezo-elements are under high elastic preload. The same design principle can also be applied generally to force pressure and acceleration sensors. The elastical clamping force, vital for perfect force transmission to the piezo-elements, is for assembly purposes easily overcome by a proper lateral clamping force.

Abstract: A method and apparatus for sensing the vibrational response of a slider of predetermined dimensions during contact with one or more surface asperities on a recording surface, separating the response into its individual bending mode frequency component responses, determining one or more bending mode frequency responses which display monotonic behavior with increasing asperity interference, and designing a mode selection sensor optimized to detect the monotonic bending mode frequency identified. The mode enhanced sensor is designed by first analyzing the stress distribution of the slider corresponding to the monotonic bending mode frequency, identifying regions of the slider which experience substantially positive or substantially negative stress, and partitioning the upper conductive layer of a piezoelectric sensor to form a partitions corresponding to each of the identified regions. The sensor may be further enhanced by tailoring the partitions to exclude undesirable stress contributions.

Abstract: A technique for measuring mechanical force by exploiting the static electric polarization developed by piezoid elements in response to application of mechanical pressure, the magnitude of the polarization being representative of the magnitude of the mechanical force applied to one or more piezoid elements by disposing the piezoid elements adjacent to an electron transmission medium capable of sustaining an electric field internally, in which the polarization developed by the piezoid elements repel particles of like charge from the adjacent surface of the transmission medium and attract particles of opposite charge to the adjacent surface. By supplying a current of charged particles to one end of the transmission medium and separately collecting the charged particles toward different surfaces of the transmission medium, the strength of the polarization, which is representative of the strength of the applied mechanical forces, can be measured.

Abstract: An enhanced piezoelectric sensor for detecting a predetermined bending mode frequency in the vibrational response of a slider with dimensions smaller than the conventional 100% slider during contact with one or more surface asperities on a recording surface. A method for making the enhanced sensor is also disclosed. The sensor comprises a substantiality rectangular slab of piezoelectric material having a charge response which corresponds to in-plane stress under free boundary conditions. Enhancement is achieved by partitioning an upper conductive layer along the lines of symmetry of the slider's stress distribution, which is related to the piezoelectric material's generated charge. In the preferred embodiment, the conductive layer is partitioned into two electrically isolated regions symmetric about the sensor's lateral axis. The design facilitates the isolation of a high frequency bending component which has been found to be monotonic with increasing surface asperity interference.

Abstract: A sensor has a sensing region that responds to a surface property by producing an output signal. The sensor has a spatially distributed shape or sensitivity so that the output decreases away from a central part of the sensor, and thus the outputs of plural sensors combined have finite spatial transform as well as high roll off in spatial frequency. Preferably the output decreases to zero at edges of the sensor, and conditions of continuity or vanishing may be imposed on first or higher order derivatives. An edge sensor suitable for mounting at the edge of the structure has its weight function obtained by processes of reflecting and inverting the weight function at an edge. A sensor system employs plural such sensors and edge sensors to produce bounded spatial transfer functions for characterizing the structure. Embodiments of piezeoelectric, resistive, capacitive and thermal sensors are described.

Abstract: A humidity sensor device which utilizes a humidity-sensitive piezoelectric polymer film as a transducer element. In a preferred embodiment a pair of excitation electrodes and a pair of pickup electrodes are provided on such a polymer film, a suitable excitation voltage is applied to the excitation electrodes and the resultant transverse piezoelectric effects are detected in the form of an electrical output voltage from the pickup electrodes. The electrical output signal is converted to the humidity value of the gaseous environment based on a prior calibration. Typically, an odd nylon such as nylon-11 or nylon-7 is used for the piezoelectric element and a rectangular, uniform and porous graphite films are deposited thereon as electrodes. The humidity sensor device of this invention can be used over a wide temperature range and can withstand repeated exposure to harsh temperature conditions over a long period of time.

Abstract: This invention relates to a method of testing multi-channel array pulsed droplet deposition apparatus (10) comprising a multiplicity of parallel channels (12) each with pulse imparting means for expelling droplets therefrom. The apparatus is located opposite a test module (20) having detecting elements (21) with channels of the apparatus opposed and close to the respective elements. Coupling fluid (23) fills the channels (12) to be tested and the space between the apparatus and the test module. Test signals are applied to impart energy pulses to the fluid in the channels opposite the detecting elements so that signals are passed to those elements by way of the fluid which are evaluated to assess the channel performance. Various forms of the detector elements and the apparatus are disclosed.

Abstract: A force transducer comprising: a silicon semiconductor having a crystal face of (110); a pair of input-output shared electrodes mounted on the crystal face of the silicon semiconductor in mutual confronting relationship in a direction of <110> of the crystal or a direction equivalent to the direction of <110>; a force transmission block connected to the crystal face of the silicon semiconductor for transmitting a force W perpendicularly to the crystal face; and a support bed supporting the silicon semiconductor and connected to the silicon semiconductor at a face opposite to the crystal face to which the force transmission block is connected, whereby a voltage corresponding to the force W and to be measured is output from the input-output shared electrodes when the force W is applied perpendicularly to the crystal face of the silicon semiconductor via the force transmission block while a current flows in the silicon semiconductor via the input-output shared electrodes.

Abstract: Use of ultrasonic stimulation together with a pressure sensitive piezoelectric material in a sensor makes it possible to obtain three dimensional pressure measurements on an object in one operation. A piezoelectric material which is manufactured with a conductive surface on both sides, and shear orientation (i.e. piezo voltage produced by pressure on the material is sensitized in a single axis of the shear plane), and generates a proportional voltage when stretched or compressed (and tension and compression is sensed by the generation of opposite polarity voltages), makes it possible to measure normal forces by ultrasonic stimulation, and shear forces by the generation of piezo voltages, using the same sensor. In a preferred embodiment, multiple sensors are disposed in a high density array, and the various axes for the three dimensional measurements are obtained by varying the orientation of each sensor relative to an adjacent sensor.

Abstract: In a known magnetic field detector, an electrical coil (8) is secured to a motion-sensitive, for example piezoelectric sensor (3); this electrical coil is charged with an electrical current for detecting the magnetic field with the sensor (3) and an evaluation means (14) which follows thereupon. In order to also be able to employ the magnetic field detector given arrangement thereof in an implantable medical device as activity sensor for the physical activity of a patient, the current charging of the coil (8) can be switched on and off with a control signal (21), whereby the control signal (21) is utilized for characterizing the sensor signal as an activity signal corresponding to the physical activity or as a detection signal that detects a magnetic field.

Abstract: A mounting assembly for a piezoelectric airblast gage includes a steel insert into which the gage is screwed. The insert is contained within a steel housing to provide a protective enclosure for the piezoelectric gage and its associated electronics. The insert is clamped inside the housing by means of a steel clamping ring which is bolted to the housing. Gaskets surround the insert on all surfaces which might come in contact with the steel housing or clamping ring. Prior to final assembly, the external electronics package for the piezoelectric gage is shock-isolated by filling the cavity beneath the insert with a shock-mitigating substance. Once fully assembly, the top of the insert and the piezoelectric gage are flush with the top of the housing.

Abstract: A thin disk force sensor having measuring elements of not more than five layers including force introducing layers welded under preloading to a thin disk housing. The measuring elements, weld and disk housing are planarized. A vapor deposited layer is selectively applied to the force measuring elements to increase the applied force compared to the housing.

Abstract: This invention relates to a semiconductor sensor for detecting external physical forces, such as acceleration, contact pressures, air pressures, mechanical vibrations, etc. The semiconductor sensor according to this invention is characterized by the use of compound semiconductors of high piezoelectricity, such as GaAs, etc. Conventionally sensors of the cantilever type, diaphragm type, etc. are made of silicon. These prior art sensors have low detection sensitivity, and their characteristics tend to deteriorate. The sensor according to this invention is made of GaAs, which has high piezoelectricity and can retain good characteristics of the semiconductor even at high temperatures and includes a field-effect transistor formed on the GaAs for sensing a stress. The FET is driven by a constant current or a constant voltage so as to detect a change of an electrical characteristic (e.g., threshold characteristic) due to a stress.

Abstract: A sensor containing at least one piezoelectric transducer element is operated via a common, single signal line in both possible operating modes--first, at low frequencies as a measuring element for a mechanical quantity upon utilization of the direct piezoeffect and, second, at higher frequencies as a piezoelectric resonator upon utilization of the inverse piezoeffect for electrical excitation of mechanical oscillations and of the direct piezoeffect for generating the piezoelectric reaction. A high-frequency signal (u.sup.HF, u.sub.F) that describes the resonant characteristic and a lower-frequency signal (u.sub.NF, u.sub.Q) that describes the mechanical influence are generated from the measured signal on the signal line. The faultless function of the sensor together with the appertaining measuring amplifier, for example, can thus be monitored immediately during a measurement with the sensor or a simultaneous measurement of two different quantities can be undertaken.

Abstract: A method for sensing pressure within a work object including placing an electrically deformable member on the work object so as to cover a portion of the surface area thereof; applying electrical energy to the member to cause the member to deform thereby applying pressure to the portion of the surface area of the work object; and sensing the tension in the member as a result of the amount of resistance to deformation imparted by the pressure within the work object.

Abstract: An apparatus for measuring force applied to a blank resting on a tool supported by a tool holder includes a tubular piezoelectric body having a central aperture extending between a first end and a second end of the body, a plurality of legs attached to an outer surface of the body and each having a free end extending beyond the first end of the body, and an elongated tube extending through the central aperture of the body, a first end of the tube terminating between the first end of the body and the free ends of the legs. Indica are provided on an outer surface of the tube for indicating the position of the body in a cavity formed in a tool holder. An electrical cable has a pair of conductors electrically connected to the body for generating a sensor output signal. Potting compound is forced through an interior of the tube to encapsulate the legs, the body, the first end of the tube and the cable to retain the apparatus in the cavity.

Abstract: A vortex sensor 14 measures a flow rate of a fluid flowing through a flow passage by detecting alternating pressure variations 26a and 28a generated by a shedding body 16 placed in the flow passage. The vortex sensor 14 includes a sensor housing 32 enclosing piezoelectric sensing elements 62, 64 which are acted on by a movable member 30. The lifetime of the sensing elements in the closed interior is enhanced by providing surface barriers, oxidizing exposed interior surfaces, or providing a gas reservoir. In applications where fluid leakage may be accepted, a controlled leak restrictor provides a limited rate diffusion path to the atmosphere allowing a minimum partial pressure of oxygen to be maintained.

Abstract: A device is disclosed for detecting the presence and direction of air flow through a passageway having a first opening and a second opening for air to flow therethrough in either a first direction or a second direction. The device comprises a piezoelectric sensor located within the passageway. A flow director is provided within the passageway for directing air flow through the passageway for impingement upon the sensor. The sensor generates a first electrical signal when air flows through the passageway in the first direction and a second electrical signal when air flows through the passageway in the second direction. A discriminator is electrically connected to the sensor for receiving the first and second electrical signals and for discriminating between the two signals to identify the direction of air flow through the passageway.

Abstract: A contact pressure sensor including a semiconductor chip having opposite surfaces, at least one pressure sensing element provided in one of the opposite surfaces of the chip, a spacer member supporting the other surface of the chip, a substrate having a surface to which the spacer member is fixed, the one surface of the chip being pressed against an object which produces a pressure, so that the at least one sensing element detects the pressure produced by the object, a first connection terminal provided in the one surface of the chip, a second connection terminal provided in the surface of the substrate, and a flexible flat cable connecting between the first and second connection terminals, the flexible flat cable being bent into two portions one of which extends along a side surface of the spacer member and the other of which extends along the surface of the substrate.