Abstract: An electromechanical sensor is provided which comprises an n-type semiconductor region which defines a flexible member surrounded by a thicker base portion; at least one piezoresistor formed in the semiconductor region; an n+ region formed in the thicker base portion; a first insulative layer which overlays the piezoresistor and which extends at least from the piezoresistor to the first n+ doped region; a guard layer which overlays at least a portion of the first insulative layer such that the guard layer overlays the piezoresistor and extends at least from the piezoresistor to a point adjacent to the n+ region; and a first bias contact which electrically interconnects the n+ region and the guard layer.

Abstract: A resistive strain gauge pressure sensor including upper and lower housings coacting to define a pressure chamber within the housing. A board member is clamped between the housings and defines a diaphragm portion which extends across the pressure chamber to divide the pressure chamber into upper and lower chamber portions. All of the circuitry of the sensor is screen printed onto the lower planar face of the board member including the various resistor elements of the strain gauge assembly, the various elements of the conditioning circuit receiving the output of the strain gauge assembly, and the various further leads required to connect the circuitry elements to the terminals of the sensor. The sensor terminals are provided by a plurality of connector pins extending downwardly through the board member for connection at their respective lower ends to the circuitry provided on the lower face of the board member.

Abstract: A pressure sensor comprising a pressure sensing assembly 24 and a pressrue transmitting medium 26 disposed within a main body 20 a seal assembly 34,35,36 disposed between the pressure sensing assembly and the main body for sealing between them against said pressure transmitting medium while allowing an easy attachment and detachment of the pressure sensing assembly relative to the main body. The pressure sensing assembly may comprise a sensing element 27 for detecting pressure, a base plate 25 for sealingly supporting the pressure sensing element within the main body and a pressure transmitting pipe 26 for transmitting the pressure to be detected to the element, and an O-ring in contact with the pressure transmitting pipe. A filling passage 15 which may be closed by a plug screw 16 may be disposed in the main body for filling the detection cavity with the pressure transmitting medium.

Abstract: An overpressure-protected, differential pressure sensor (37) is formed by depositing diaphragm material (24) over a cavity (23) formed and filled with sacrificial material (22) into a front surface of a substrate. The sacrificial material (22) is then removed to create a free diaphragm. The floor of the cavity (23) defines a first pressure stop to limit the deflection of the diaphragm in response to pressure applied to the top of the diaphragm. A port (33) is created to allow pressure to be applied to the bottom side of the diaphragm (24). An optional second pressure stop, which limits the deflection of the diaphragm in response to pressure applied to the bottom side of the diaphragm, is formed by bonding a cap (35) to standoffs (34) placed around the top of the diaphragm. The standoffs are spaced to allow pressure to be applied to the top of the diaphragm.

Abstract: A force transducer usable tokodynamometer for measuring intrauterine pressure and motion, and for measuring other force exerted by human body or other organisms. The tokodynamometer has a cavity filled with an incompressible fluid and closed by a flexible diaphragm disposed for contacting the body portion being studied. A zero-displacement fluid-pressure transducer is in the cavity and provides an electrical signal responsive to pressure in the fluid, as body force acts through the flexible diaphragm to induce pressure in the fluid. Changes in intrauterine pressure or other body forces are thus measured with no significant physical displacement of a transducer or other force-measuring element. The fluid-filled cavity has the shape of a truncated cone with the diaphragm at the larger end and the transducer at the smaller end, increasing the sensitivity of the transducer.

Abstract: A pressure sensor having a ceramic support, a first ceramic layer attached to a peripheral portion of one side of the ceramic support, and a second ceramic layer which is attached to a peripheral portion of another side of the ceramic support such that the pressure sensor is shaped as an integral assembly. The ratio of the thickness of the first ceramic layer to that of the second ceramic layer is in the range of 1:10 to 1:1. The ratio of the thicknesses of the first and second ceramic layers to thickness of the ceramic support is no more than 1:2. The pressure sensor further includes a hollow space formed between the ceramic support and at least one of the first and second ceramic layers so that, after shaping as an integral assembly, the ceramic layer or layers will work as a diaphragm that is capable of deformation under pressure.

Abstract: A pressure sensor comprising a hollow main body (11) defining a bore (14) extending therethrough and having a detection end and an output end. A pressure sensing assembly is disposed within said bore (14) to divide it into a detection cavity (17) and an output cavity (18) through which output signal lines from said pressure sensing assembly extend. A flexible diaphragm (19) is attached to the detection end of the bore to define a sealed detection cavity (17) in which a pressure transmitting liquid is filled. The pressure sensing assembly comprises support plate (24) welded to said main body (11) and supporting a pressure sensing element (26) within said detection cavity (17) through a mounting bed (4). The signal lines sealingly extend through said support plate (24) from said detection cavity (17) to said output cavity (18).

Abstract: A semiconductor pressure-detecting apparatus includes a semiconductor chip having a diaphragm and a frame molded within a resin with the diaphragm exposed. A reference pressure chamber may be provided between the diaphragm and the frame. Since the diaphragm is exposed, a medium, the pressure of which is to be measured, easily contacts the diaphragm. Therefore, if the stem is connected to a case containing the medium, a high pressure can be measured.

Abstract: A semiconductor transducer or actuator is disclosed. The transducer and actuator each include a deflecting member with corrugations producing increased vertical travel which is a linear function of applied force. An accurate and easily controlled method that is insensitive to front-to-back alignment is also disclosed for forming uniform corrugations of precise thickness; independent of the thickness of the deflecting member. The cross-sectional shape of the corrugations is not limited by the etching technique, so that any configuration thereof is enabled.

Abstract: A pressure sensor Comprising a disk-type base part having a preferably central opening spanned at one end by a surface-type pressure transducer, a pressure receiving part having a diaphragm arranged at distance from the other end side of said opening and integrally formed with a rigid ring having the same peripheral dimensions as the disk-type base part and being connected thereto. A distance holder is provided between the diaphragm and the pressure transducer fully transmitting any deformation of the diaphragm to the pressure transducer. Such a pressure transducer may be manufactured by a simple and cost-effective procedure with the various elements formed of ceramic, sintered and combined.

Abstract: A pressure sensor assembly is provided containing a substrate having signal conditioning circuitry disposed on both surfaces of the substrate, with the critical pressure sensing element disposed on one surface of the substrate and the laser trimmable resistors disposed on the other surface of the substrate. The preferred ported housing of this invention seals the one side of the substrate containing the pressure sensing element thereby forming a pressurizable chamber, while allowing the signal conditioning circuitry and resistors on the other surface exposed for calibration by laser trimming of the resistors. This eliminates the requirement for a separate housing for the critical pressure sensing element. In addition, when the preferred ported housing is mounted to the pressure sensing side of the substrate for formation of the sealed pressure chamber, the through-holes which electrically interconnect the signal processing circuitry on both sides of the substrate are also concurrently sealed.

Abstract: A semiconductor pressure sensor is manufactured by integrally encapsulating a semiconductor pressure, sensor chip, a pedestal, leads, wires and a die pad in an outer package except for the surface of a diaphragm of the semiconductor pressure sensor chip and the reverse side of the die pad. The ratio of the thickness of the pedestal to the thickness of the semiconductor pressure sensor chip is 7.5 or less, while the ratio of the diameter of an opening formed in the outer package at the surface of the diaphragm and the diameter of the diaphragm is 1 or more. The thermal stress generated in the semiconductor pressure sensor chip can freely be reduced to a desired value, and a semiconductor pressure sensor exhibiting a desired accuracy can therefore be obtained. Furthermore, since the semiconductor pressure sensor can be manufactured by an ordinary IC manufacturing process, a semiconductor pressure sensor with reduced cost and having high quality can be produced.

Abstract: A pressure sensor for determination of pressure in a combustion chamber of an internal combustion engine, particularly for motor vehicles has a housing, a membrane associated with the housing, a sensor element, a plunger supplying a pressure to be determined to the sensor element and located in the housing. The housing has at least one housing opening and a shaft and the membrane closing the opening of the housing and is connected with the shaft of the housing in the region of a side wall so that a bottom of the membrane is flexible and a pressure to be determined is transferable to the plunger, a counter bearing for the plunger. A support is provided for a hybrid and composed of ceramic material and located on the counter bearing for the plunger. The sensor element is a piezoresistive measuring element and located on the hybrid so as to produce an electrical signal corresponding to the pressure.

Abstract: For transducing a physical quantity into an output electric signal, a transducing device comprises lower and upper dielectric substrates and a physical quantity sensor mounted on a predetermined portion of a substrate surface of the lower dielectric substrate for sensing the physical quantity to produce a sensed signal representative of the physical quantity. The upper dielectric substrate has an upper surface and a lower surface which is on a different portion of the substrate surface. In order to receive the sensed signal and produce the output electric signal, an electric circuit is mounted on the upper surface and electrically connected to the sensor through a bonding wire which is shorter than that used in a conventional device. The electric circuit (14) receives the sensed signal through the bonding wire (15) and produces the output electrical signal. The physical quantity may be fluid pressure which a fluid has and is higher or lower than atmospheric pressure.

Abstract: A pressure sensor including a semiconductor strain gauge and resistors for compensating temperature, a zero point or the like and made of the same material as that of said semiconductor strain gauge are formed on a metal diaphragm thereof. The resistors for the compensating circuit and the strain gauge are simultaneously formed by patterning a polycrystalline silicone thin film or the like laminated on the diaphragm. As a result, the number of the elements and the manufacturing processes such as a soldering process are reduced for the purpose of improving manufacturing yield. In order to widen the zero point compensating range, a plurality of zero-point compensating resistors, if formed, are disposed on a circumference relative to the center of the diaphragm so as to reduced the scattering in the level of the resistance of each of the resistors.

Abstract: A monolithic pressure and/or temperature transducer comprises at least two sensitive semiconductor layers of III-V material sensitive to pressure and to temperature and supported by a common substrate of III-V material, which two layers comprise: a first layer doped with donor type impurities at a first concentration and having a first resistivity as a function of pressure and of temperature; and a second layer doped with donor type impurities at a second concentration different from the first concentration and having a second resistivity as a function of pressure and of temperature, which second resistivity depends on temperature in a different manner than the first resistivity.

Abstract: A pressure transducer circuit is provided which includes a bridge arrangement of piezoresistors which are connected to a diaphragm that is sensitive to a pressure which is monitored. The output of the sensor bridge is provided to a preamplifier which is, in turn, associated with an attenuation network and compensation circuitry. The transducer incorporates a plurality of temperature sensitive resistors within the compensation circuit and these temperature sensitive resistors are produced at the same time and during the same manufacturing step as the piezoresistors of the bridge arrangement. In addition, they are produced using the same dopant and are implanted or diffused in the same semiconductor layer as the piezoresistors. The pressure transducer circuit incorporates a plurality of trimmable resistors which are adjusted during a calibration stage to compensate for temperature variations and nonlinearity of the numerous components in the circuit.

Abstract: A pressure transducer (50) of the type utilizing a diaphragm (8) with strain sensitive elements (14) formed in the diaphragm surface where the strain sensitive elements (14) are connected to an electronics assembly (4) to produce an electrical output in response to deflection of the diaphragm (8). A diaphragm assembly (26) is bonded to an intermediate support member (28) which is in turn bonded to a main support member (32) which is joined to a support collar (42) and hermetically sealed thereto with a sealing glass (40) where each element (2, 28, 32, 42) has a substantially matched coefficient of thermal expansion so as to reduce any induced thermal stresses and resultant measurement errors where the sealing glass (40) and the support collar (42) have a greater coefficient to produce a compressive type seal at high temperature.

Abstract: A transducer having a plurality of sensing elements disposed in a single diaphragm wherein each of the sensing elements is spaced from every other of the sensing elements a predetermined distance so as to control interference among the sensing elements. Each of the sensing elements preferably comprises a plurality of piezoresistors each of which are coupled in a Wheatstone bridge configuration. This transducer achieves sensitive, accurate, high spatial resolution measurements of non-uniform pressures.

Abstract: A low cost piezoresistive pressure transducer utilizing premolded elastomeric seals in which at least one seal is electrically conductive. A piezoresistive stress sensitive element in the form of a diaphragm of semiconductor material having a thickened rim is held at its rim between a pair of premolded elastomeric seals in a two piece housing. Electrical connections with external circuitry are made by conductive paths through one of the elastomeric seals which makes contact with electrical leads which pass through the housing wall.

Abstract: A diaphragm type pressure sensor comprises a transducer main body and a protective cover. The main body has a diaphragm portion, a support portion supporting the periphery of the diaphragm portion, and a trunk portion having a shoulder surface which surrounds the support portion and which forms a step surrounding the support portion. The support portion projects upwardly from the inner periphery of the shoulder surface, and is separated by the shoulder surface from the protective cover fitted over the trunk portion. Therefore, the diaphragm portion is not easily influenced by an external force applied to the trunk portion from the protective cover. The main body may further has an abutting surface which forms another step surrounding the support portion, and which abuts against a lower end of the protective cover.

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.

Abstract: A silicon pressure sensor chip has a shear element on a sculptured diaphragm. The shear element is a piezo-resistive four-terminal resistor which is oriented so as to respond to the in-plane shear stress component in the diaphragm. The shear element is located on a thick shelf which is a portion of the sculptured diaphragm, which also has a thinner portion. This diaphragm configuration increases the bending moment at the location of the sensing element through the load of the thin portion of the diaphragm, which is suspended along the periphery of the thick shelf.

Abstract: The invention improves upon the diaphragm/beam-type transducers and method of manufacturing same described in U.S. Pat. No. 4,368,575. The new transducers and method of manufacture utilize strips or slivers of silicon or germanium which are larger than the individual strips used in the apparatus and method described in U.S. Pat. No. 4,368,575 by an amount sufficient to permit (a) the formation of two gages on each strip and (b) the forming of bonding pads on each gage. The bonding pads are formed on the gage strip before the strip is bonded to the beam, so that formation of the bonding pads and bonding of the strip to the beam can be handled automatically. The strips are mounted to one side of the midpoint of the beams, so that when a diaphragm/beam is deflected by application of a fluid pressure, one of the two gages will undergo a tension strain while the other gage will undergo a compression strain.

Abstract: A structure and method of making a piezoresistive transducer with reduced offset current. The transducer is comprised of a piezoresistive die having a support rim and a diaphragm, and a support housing having a wall and an aperture. The shape of the diaphragm is matched with the shape of the aperture while the shape of the support rim is matched with the shape of the wall. By matching these shapes, temperature induced stresses are reduced, thus reducing temperature induced offset currents.

Abstract: A resistive strain gauge pressure sensor including upper and lower housings coacting to define a pressure chamber within the housing. A board member is clamped between the housings and defines a diaphragm portion which extends across the pressure chamber to divide the pressure chamber into upper and lower chamber portions. All of the circuitry of the sensor is screen printed onto the lower planar face of the board member including the various resistor elements of the strain gauge assembly, the various elements of the conditioning circuit receiving the output of the strain gauge assembly, and the various further leads required to connect the circuitry elements to the terminals of the sensor. The sensor terminals are provided by a plurality of connector pins extending downwardly through the board member for connection at their respective lower ends to the circuitry provided on the lower face of the board member.

Abstract: A piezoresistive device, in which separation grooves having a cross section defined by four (111) planes and including side walls of a silicon oxide film are formed in a surface area of a semiconductor substrate having a surface of (100) plane, and at least one piezoresistor having an inversed triangular cross section defined by one (100) plane and two (111) planes is formed in the surface area of the semiconductor substrate and is surrounded by the separation grooves for separating the piezoresistor from the semiconductor substrate.

Abstract: This invention provides a semiconductor film pressure sensor in which the pressure-sensitive resistance layers are made of an n-type polycrystalline silicon layer, and a method of manufacturing the sensor. In the semiconductor film pressure sensor of the invention, the pressure-sensitive resistance layers are formed on a diaphragm, and in addition a coarsely adjusting pattern and a finely adjusting pattern for zero point adjustment and the resistors of a temperature compensating circuit are formed on the diaphragm using the same n-type polycrystalline silicone layer. In formation of the n-type polycrystalline silicone layer, the substrate temperature is held at 500.degree. to 600.degree. C. The coarsely adjusting pattern and finely adjusting pattern for zero point adjustment, and the resistors of the temperature compensating circuit are formed in the same step as the pressure-sensitive resistance layers.

Abstract: A semiconductor pressure sensor comprises a diaphragm formed by anisotropic etching of silicon single crystal, characterized in that an etch-stop layer is provided at the site where etching is to be stopped, and that an etch-stop layer having insulating property is provided as the insulating layer of the pressure-sensitive portion.

Abstract: There is disclosed an apparatus and structure for a pressure transducer employing silicon carbide and utilizing p-type SiC as a diaphragm with n-type mesa SiC force sensing resistors integrally formed on the surface of the diaphragm. The p-type SiC diaphragm is positioned on top of an annular ring of silicon which is formed from a silicon wafer utilized as the supporting wafer for the process. The structure depicted is a given conductivity SiC diaphragm having opposite conductivity SiC resistors positioned thereon and fabricated by processing techniques utilizing selective etching properties of SiC.

Abstract: A semiconductor pressure sensor having a diaphragm formed over the surface of a semiconductor substrate by thin film forming technique is provided.

Abstract: A pressure transducer having means for improving the linearity and sensitivity of an output signal from the pressure transducer. Ribs and bosses are introduced in the diaphragm region to collect the moments caused by a difference in pressure on the two sides of the diaphragm and thus improve device sensitivity. In addition, the ribs and bosses prevent stretching of the piezoresistors thus improving the linearity of the device. A constraint can also be included to improve the alignment of the piezoresistors thus improving the linearity of the device.

Abstract: An apparatus and method for compensating for temperature dependent offset and fixed offset in a resistance bridge is disclosed. The apparatus comprises a resistance bridge, a compensation network and an instrumentation amplifier. The uncompensated output of the bridge is applied to the input of the instrumentation amplifier. The output of the compensation network is fed into the instrumentation amplifier to compensate for the temperature and offset dependent components of the bridge output. The output and resistance of the bridge are measured under conditions of constant pressure and temperature for different temperatures and pressures and the temperature coefficient of resistance, temperature coefficient of offset and temperature coefficient of sensitivity are calculated. These coefficients are used to select compensation network resistors.

Abstract: A pressure sensor has a thin plate diaphragm having a strain detecting section thereon, and a support member for receiving and properly positioning the diaphragm within a stepped bore structure. The pressure sensor with which the strain detecting section is formed on the diaphragm surface is formed by the use of semiconductor manufacture technology by making the diaphragm of the pressure sensor in the form of a thin plate member. The diaphragm and the support member are joined together by diffusion bonding, and heat treatment for this diffusion bonding is also utilized to crystallize the semiconductor strain gauges.

Abstract: A fabrication process of a semiconductor pressure sensor is described. A first recess and a second recess, which is deeper than the first recess, are formed in a first surface of a semiconductor substrate. A reinforcement layer is formed on the entire first surface. A second surface of the semiconductor substrate is then polished until a part of the second recess appears on a side of the second surface. After that, a resistance element is formed in the second surface at a region opposing the first recess.

Abstract: Pressure sensor having a silicon diaphragm chip. The diaphragm in the chip is less than 200 mils in diameter and has an ultrasonic resonant frequency that varies with pressure exerted on it. The chip has resistors with values that change with fluctuation of the chip. The changing resistor values are fed to a supporting electronics that detect the resonant frequency of the diaphragm and indicate measurement of the pressure exerted on the diaphragm. The supporting electronics feed back a signal corresponding to the detected resonant frequency for a sensed pressure to a piezoelectric device that drives the diaphragm to sustain its vibration.

Abstract: Unfired ceramic tape is fired to a ceramic substrate during the laminar fabrication of a thick film force sensing element to provide the fabricated sensing element with a force sensing zone which is effective in response to the application of force thereto to induce strain in the fired ceramic tape. A conductor and thick film resistor system is printed and fired to the tape during the fabrication process to provide the fabricated sensing element with an electrically detectable signal correlating with the induced strain. Accelerometer and pressure sensor embodiments are disclosed. The invention is well-suited for the commercial mass-production of sensing elements, such as for automotive vehicle usage, because it can practiced through the use of automated production processes.

Abstract: The apparatus for sensing pressure comprises a header, having at least one input port for receiving a substance under pressure. A substrate, having a wafer-like shape with a relatively large surface area in comparision to its thickness, includes at least one internal passage to couple the substance under pressure. A pressure sensing element is mounted onto the surface of the substrate over an exit port of the internal passage coupling the substance under pressure. The substrate is bonded to a surface of the header at extreme locations from a location in which the pressure sensing element is mounted. Thus isolation is provided for the pressure sensing element from unwanted stresses induced in the substrate.

Abstract: A pulse wave detecting apparatus for detecting a pulse wave produced from an arterial vessel in a body portion of a subject, including a semiconductor substrate having a press surface at which the semiconductor substrate is adapted to be pressed against the body portion, the semiconductor substrate having a recess in a surface thereof opposite to the press surface and thereby including a diaphragm portion having a thin wall, and a pressure sensing device provided on the diaphragm portion, for converting a pressure transmitted from the arterial vessel to the diaphragm portion, into an electric signal.

Abstract: A pressure sensor package, having a dual-in-line package (DIP) structure as commonly used in the semiconductor industry, comprises a first layer of predetermined material, having at least one internal passage for transmitting a fluid under pressure from a first surface of the first layer to a second surface of the first layer. A pressure sensitive element is bonded to the first surface of the first layer, and covers an exit from the first surface of the internal passage. A lead package, has a plurality of pins, each pin being perpendicular to the first surface of the first layer and placed along a first and second length of the first layer exterior to the pressure sensor package, and having a spacing conforming to the DIP configuration. Predetermined points of the pressure sensitive element are electrically connected to predetermined pins. A second layer of predetermined material is bonded to the first surface of the first layer providing an enclosed spaced for the pressure sensitive element.

Abstract: A silicon pressure die is bonded to a borosilicate substrate above a pneumatic port. A Wheatstone bridge circuit is formed on the silicon pressure die and has bridge elements of silicon doped with boron to a deposit density level of approximately 1.times.10.sup.19 -10.sup.21 boron/cm.sup.3. A current source is provided to excite the Wheatstone bridge circuit. In addition, a temperature sensor is provided to provide temperature readings.

Abstract: A pressure sensor (38) is proposed with strain gauges (18, 20, 22, 24) such as thick-film resistance strain gauges arranged on a diaphragm, these gauges being preferably connected to form a Wheatstone bridge, where branches of the bridge circuit have compensating resistors (26, 28, 30, 32). The compensating resistors are arranged outside the active area (17) of the diaphragm.

Abstract: A semiconductor chip with a gauge pressure sensor section and an absolute pressure sensor section is anodically bonded, in a vacuum, to a glass mount with an evacuated space between the absolute-pressure sensor section and the mated surface portion of the glass mount. The pressure to be measured is received by the reverse surface of the gauge pressure sensor section. Since no complicated package is mounted within the outer package, the assembly of the sensor is easy. Further, since the pressure sensor has two sensor sections, namely, the gauge pressure sensor section and the absolute pressure sensor section, the sensor can be used as an absolute pressure sensor of the reverse-surface pressure-receiving type.

Abstract: A pressure detection apparatus is provided with a semiconductor pressure sensor interposed between a reference pressure side and a measured pressure side and adapted to detect pressure in fluid corresponding to the difference between the reference pressure and the measured pressure. In addition, the apparatus is connected to an output side of the semiconductor pressure sensor and also includes a sensor offset compensation circuit for adjusting an output value from the semiconductor pressure sensor at a predetermined temperature to provide zero-point temperature compensation, thereby making it possible to compensate for an offset value of the semiconductor pressure sensor. This apparatus is not affected by the external atmospheric temperature, thus enabling it to provide fully stable operation.

Abstract: In a pressure transmitter, a central region of an isolator diaphragm with a substantially flat shape at an undeflected position near room temperature has a depressed shape at a deflected position at a colder temperature. The isolator diaphragm is over a shaped concavity in a transmitter body with a concave shape which corresponds to the depressed diaphragm shape to reduce output error.

Abstract: A device for measuring the deformations of a flexible diaphragm (1) sealed by its periphery to a support (2) and wherein are formed four sensors constituted by a thick layer of piezo-resistive material and connected as a Wheatstone bridge. The sensors are arranged on both sides of the diaphragm with, on each surface, a sensor (R3, R4) at the neighborhood of the center and a sensor (R1, R2) at the neighborhood of the periphery. A central sensor and a peripheral sensor of the opposite surface are arranged in opposite legs of the bridge, two sensors of the same surface having their connection point connected to a supply terminal of the bridge. The device serves as a pressure sensor.

Abstract: A semiconductor pressure sensor (10) includes a substrate (12) as semiconductor material which comprises an active surface (14) for receiving integrated components (26, 28) and a rear side (16) in which to form a diaphragm (20) adjoining the active surface (14) and exposed to the pressure to be measured a recess surrounded by thick edge regions (22, 24) is formed. On the active surface (14) integrated components are provided which under the influence of mechanical deformations of the diaphragm (20) vary one of their electrical parameters. The substrate (12) is connected to the support element (34) in the region of the active surface (14) surrounding the diaphragm (20) by using an elastomer seal (40). The diaphragm (20) is in communication from the rear side of the substrate (12) with a supply conduit (44) for the pressure to be measured.

Abstract: A piezoresistive pressure transducer employing a sapphire force collector diaphragm having piezoresistive films of silicon epitaxially formed on a major surface thereof, preferably in a Wheatstone bridge pattern. The piezoresistive elements of the Wheatstone bridge are oriented and located so that the pressure sensitivity is maximized, while the linearity errors of the output voltage of the Wheatstone bridge in relationship to the applied pressure are minimized. The silicon piezoresistive film is preferably of a thickness of from 1000 to 60,000 angstroms and is doped with boron in the range of from 5.times.10.sup.17 to 9.times.10.sup.20 atoms/cc. Electrical arms and contact pads are also formed on the major surface of the force collector diaphragm. The diaphragm is mounted on a ceramic body having a cavity in the upper surface thereof, the diaphragm enclosing the cavity so as to form a protective chamber with the piezoresistive silicon films within the chamber.

Abstract: A monitoring system for testing the integrity of seal structures, filled with an electrically non-conductive fluid and for validating measurements of a measurement device. The monitoring system includes electrodes disposed in the fluid for measuring an electrical property of the fluid. The system indicates when the measured electrical property changes, which indicates contamination of the fluid.

Abstract: A silicon membrane pressure sensor which has a carrier chip and a membrane chip 3 for which overload protection is desired to protect against the pressure on the front side of the membrane. An overload member 7 is mounted between the carrier chip 2 and the membrane chip 3 such that the overload member is connected to the membrane chip at a middle island portion 5 of the membrane chip 3 and with a first distance D1 from the carrier chip 2 in the non-loaded condition such that when pressure occurs the overload member will remove the load on the membrane chip.