Abstract: Disclosed herein a semiconductor pressure sensor, which is capable of carrying out temperature compensation in high accuracy, having a piezo resistance layer consisting of a single crystal layer formed by lateral seeding. In this semiconductor pressure sensor, a piezo resistance is so formed as to contain no crystal sub-grain boundary. Thus prevented is inconvenience of reduction in resistance temperature coefficient, which is caused when the piezo resistance contains the crystal sub-grain boundary. Thus, the piezo resistance can be set at a high resistance temperature coefficient, whereby a semiconductor pressure sensor capable of carrying out temperature compensation in high accuracy is obtained.

Abstract: An electronic pressure sensor (10) is enhanced by attaching a sensor die (18) to a stress isolation platform (12) using an adhesive (42) having a similar thermal coefficient of expansion. The adhesive provides a hermetic seal between the stress isolation platform and the pressure sensor die. A via (20) in the stress isolation platform provides an opening for pressure to be applied to the sensor die. The stress isolation platform is attached to a plastic package body (16) via a semi-rigid adhesive (40) for providing stress isolation and a hermetic seal between the package body and the stress isolation platform. Any hostile chemical entering the via contacts an exposed diaphragm (50) of the sensor die to assert pressure against its piezoelectric network (52) to generate the electrical signals representative of the applied pressure but are kept away from the sensitive interconnects by the hermetic seals.

Abstract: A strain gauge exhibits temperature offset errors and span errors which vary from device to device and vary as a function of temperature. A digitally-compensated strain-gauge apparatus executes embedded calibration and compensation programs for improving accuracy over a wide temperature range. Pressure measurement error bands are reduced to approximately to 0.03% of full scale for a 5 psi device over a 0.degree. C. to 50.degree. C. temperature range. A calibration program defines parameters for compensating for such errors. During field operation, a compensation program uses the calibration parameters to generate a more accurate pressure measurement. According to the compensation scheme, current normalized voltage and bridge impedance are derived from the raw data. A first-pass temperature estimate then is derived from the result. The derived first-pass temperature estimate is plugged into a temperature offset error function to find the temperature offset error at the estimated temperature.

Abstract: An absolute pressure sensor subassembly includes a top cap bonded to a pressure sensor die and enclosing a reference vacuum. The subassembly is initially held in place within a housing by a vacuum or sublimeable solid adhesive while wire bonds from the subassembly to the housing leads are completed. A self-contained adhesive drop on the inner surface of the housing cover contacts the sensor subassembly when the cover is placed on the housing body and the sensor subassembly is supported by the adhesive drop.

Abstract: A semiconductor silicon single-crystal substrate is used in which the crystallographic axes are inclined by a predetermined angle with respect to a normal to a thicknesswise face of the semiconductor silicon single-crystal substrate. A conductive-type epitaxial layer is grown on this semiconductor silicon single-crystal substrate to a predetermined thickness such that the direction of the crystallographic axes of the conductive-type epitaxial layer coincides with the direction of the crystallographic axes of the semiconductor silicon single-crystal substrate. Accordingly, since side surfaces of a cavity portion provided in the semiconductor silicon single-crystal substrate by the etching of the substrate, i.e., side walls of the semiconductor silicon single-crystal substrate provided respectively in the longitudinal direction of a diaphragm, are each formed at an angle of 90.degree. with respect to the thicknesswise lower surface of the conductive-type epitaxial layer.

Abstract: A differential pressure sensor (10) has a sensor die (16) attached to a stress isolation package base (12) with a bonding glass (27) having a similar coefficient of thermal expansion. The bonding glass, and alternately an aluminum layer, provides a hermetic seal between the stress isolation base and sensor die. Pressure is applied to the sensor die port (24). A plastic housing (14) is attached to the stress isolation base with an adhesive (29). A port (23) in the plastic housing is filled with a silicone gel (22). A second pressure source is transferred by way of the silicone gel to the sensor die. Any hostile chemical entering the via contacts the first surface of the sensor die to assert pressure against a transducer circuit (25) to generate the electrical signals representative of the applied pressure but are isolated from the sensitive interconnects by the hermetic seal.

Abstract: A capacitive transducer includes a first electrically conductive layer, and a diamond diaphragm mounted opposite the first electrically conductive Layer so as to be moveable relative to the first electrically conductive layer. The first electrically conductive layer defines a first plate for the transducer, while the diaphragm defines the second plate for the transducer. In one embodiment of the transducer, the diamond layer is degeneratively doped providing the second plate. The microelectronic capacitive transducer preferably also includes an insulating layer on a face of the diamond layer adjacent the electrically conductive layer defining an overpressure stop for the transducer. The transducer includes absolute or differential pressure sensing embodiments. The microelectronic capacitive transducer may also be configured as an actuator. The diamond layer may be highly oriented diamond including semiconductor devices formed therein to provide signal conditioning. A fabrication method is also disclosed.

Abstract: A modular pressure sensor has a pressure-sensing element, electrical terminals, interconnections, and a support substrate. The pressure-sensing element produces an electrical signal indicative of pressure at local contacts and the interconnections apply the signal to the electrical terminals. The electrical terminals are secured to the substrate and extend along a peripheral surface of the substrate. The modular pressure sensor can mount, with different orientations, to a header to form a pressure transducer.

Abstract: A pressure sensor package (10) has a sensor body (12) for containing a pressure sensor. An elongated stem (14) has a first end connected to the sensor body (12), and a connector (24, 26) is disposed on a second end of the stem (14) for fixedly mounting the stem (14) to a mounting base (40), which is connected to, for example, a fuel tank (52). An annular sealing surface (28) is disposed on the first end of the stem (14) for pressing against a compressible seal (44) when the stem (14) is mounted to the mounting base (40), and an orifice (18) is disposed at the second end of the stem (14). The orifice 18 is connected to the pressure sensor by a passage (20, 22) through the stem body. The connector (24, 26) is spaced a sufficient distance from the sensor body (12) to substantially reduce error-inducing stresses on the pressure sensor.

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 pressure sensor includes an electrically insulating material covering wires for transmitting an electrical signal generated by a semiconductor pressure-sensing unit, the joints between the wires and the pressure-sensing unit, and the joints between the wires and leads connected to the wires for leading the electrical signal to the outside of the body casing of the sensor. Thus, detection of pressure is possible even in an intense-vibration environment, and it is also possible to reduce influences by changes in temperature.

Abstract: A general object of the present invention is to provide a semiconductor device having a stress transducer in which a temperature dependency of sensitivity of the stress transducer which utilizes a piezo resistance effect to transduce stress into an electric signal, and variations in sensitivity of several semiconductor devices can be corrected. The semiconductor device includes a reference voltage source which has a temperature dependency in accordance with a temperature characteristic of sensitivity of the stress transducer which has an electrical bridge circuit exhibiting a piezo resistance effect, and a voltage transducer having resistances and an operational amplifier. Voltage transduced by the voltage transducer is adjusted so as to correct variations in sensitivity of several semiconductor devices.

Abstract: A pressure detection gage for a semiconductor pressure sensor includes a gage portion, a pair of lead out portions, and an isolation layer. The gage portion is formed on the upper surface of a semiconductor substrate of the first conductivity type, has a predetermined sheet resistance, and serves as a piezoelectric region. The pair of lead out portions are formed as heavily doped semiconductor regions of the second conductivity type on the surface of the semiconductor substrate and are electrically connected to two ends of the gage portion. The isolation layer is formed from a lightly doped semiconductor region of the second conductivity type formed in the semiconductor substrate to surround the lead out portions.

Abstract: A pressure sensor is provided in which the pressure sensing components are isolated from a portion of an attached buffer member which is connected to a fluid conduit. The offset characteristic of the pressure sensor isolates stress from being transmitted between an attached external fluid conduit and the sensitive components of the pressure sensor. One embodiment of the pressure sensor solders a fluid conduit structure to a buffer member that is attached to a pressure sensor die. An alternative embodiment of the present invention avoids the need for making solder connections between the sensor structure and external components by utilizing elastomeric conductors and pressure seals in association with the pressure sensor composite structure and first and second housing structures. These elastomeric conductors also provide improved stress isolation. The housing structures are used to compress to the seal and the elastomeric conductor against selected portions of the composite sensor.

Abstract: A differential pressure sensor is disclosed, and in particular, there is disclosed a multiple function type differential pressure sensor capable of reducing a zero-point-change and a span change of means for detecting a differential pressure when applying a static pressure and being readily manufactured at high accuracy. The multiple function type differential pressure sensor is constructed by a semiconductor chip 1 for detecting a differential pressure, a fixing base 2 which has a joining part 21 joined to a thick part of the semiconductor chip 1 and which has a thickness less than or equal to that of the semiconductor chip 1, and also which has at least one thin part 22 in an outer periphery other than the joining part 21, and a housing 4 joined to the fixing base.

Abstract: A pressure detecting circuit compensating for temperature dependency of a zero point output voltage of a semiconductor pressure sensor. A differential amplifier circuit in a signal processing circuit of the semiconductor pressure sensor includes two transistors. Emitter currents in the two transistors are different in accordance with the temperature dependency of the zero point output voltage of a bridge circuit of a pressure detector. As a result, a difference will arise between the base-emitter voltages of the two transistors. The temperature dependency of the zero point output voltage of the bridge circuit is compensated for by the temperature dependency of the voltage differences of the base-emitter voltages.

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 stand-offs (34) placed around the top of the diaphragm. The stand-offs are spaced to allow pressure to be applied to the top of the diaphragm.

Abstract: A pressure transducer is provided with a housing member that attaches to a rigid and generally planar member, such as a ceramic circuit board. The legs of the housing member can pass through holes in the circuit board or, alternatively, can attach to edges thereof. The legs of the housing are provided with bails which have steps shaped to seize the circuit board after the legs are flexed to permit insertion of the board between them. The housing is provided with an opening that is shaped to receive a media seal, a pressure sensor die and a conductive seal between a surface of the opening and a surface of the ceramic circuit board. When the circuit board is attached to the housing, the seals and the pressure sensor die are compressed therebetween to provide good fluid sealing association between the components and to also provide electrical communication between components on the pressure sensor die and components on the circuit board.

Abstract: A resistive pressure transducer wherein a flexible diaphragm is mounted in a spaced apart relationship to the upper surface of a base member. A conductive path is deposited on one surface of the diaphragm. A resistive configuration is also deposited on the same surface of the diaphragm. The resistive configuration includes four separate resistive patterns. The first and third resistive patterns are deposited in close proximity to the outer edge of the diaphragm. The first and third resistive patterns are each comprised of three radially extending resistors, spaced apart along the periphery of the diaphragm, and interconnected by conductive material. The second and fourth resistive patterns are deposited in close proximity to the center of the diaphragm. The first and third resistive patterns measure radial strain, while the second and fourth resistive patterns measure tangential strain. The four resistive patterns each forms a separate leg of a Wheatstone bridge configuration.

Abstract: A digital pressure gauge includes a casing having a pressure sensitive member which responds when pressure is passed therethrough and a digital display member electrically connected to the pressure sensing member. The gauge includes an insulating rod which engages the pressure sensitive member and which contacts a weight sensing member in response to pressure flowing through an inlet so as to expand the pressure sensitive member.

Abstract: A semiconductor sensor (10) is built into a cable connector to provide rapid and reliable attachment of the semiconductor sensor (10) into a monitoring or control system. The sensor (10) is mounted in a package (11) having cable connector leads (12, 13, 14) extending through the package (11). The semiconductor sensor (10) is electrically attached to the cable connector leads (12, 13, 14). A housing (20,30) surrounds the package (11) and provides a protective shroud for the cable connector leads (12, 13, 14).

Abstract: A small, precise semiconductor pressure sensor has a flat, thin diaphragm of uniform thickness that is formed by a simple process. A first silicon substrate and a second silicon substrate are bonded to each other with an interface insulating film interposed between them and circuitry including gauge resistors is fabricated on the primary surface of the second silicon substrate. The interface insulating film may be disposed in the recess of a vacuum chamber and may have a two layer structure. If alignment marks are formed, the circuitry can be accurately formed relative to the vacuum chamber.

Abstract: In a semiconductor pressure sensor, a dam which prevents a sheathing resin from flowing into a diaphragm portion during the molding of the sheathing resin is disposed on the outer periphery of piezoresistors and the diaphragm portion on the surface of a semiconductor pressure sensor chip. The volume of the base and that of the semiconductor pressure sensor chip are adjusted so that a tensile force exerted upon the semiconductor pressure sensor chip by the base cancels a compressive force exerted upon the semiconductor pressure sensor by the sheathing resin when the temperature of the semiconductor pressure sensor returns to an ordinary room temperature from a high temperature. As a result, strain is not caused in the semiconductor pressure sensor chip, and therefore measurements of pressure with a high degree of accuracy can be performed.

Abstract: A low range pressure sensor includes a base plate of brittle material, and a diaphragm plate mounted on the base plate and sealed around a periphery to the base plate. Pressures are introduced to cause the diaphragm to deflect toward the base plate, and the deflection of the diaphragm is sensed through strain gauges to provide an indication of the pressure. The diaphragm is provided with a plurality of individual support posts on a side facing the base plate, so that when the diaphragm is deflected toward the base plate under high overpressures the support posts will support the diaphragm against movement to avoid failure or breakage of the diaphragm. The number of support posts can be varied as desired.

Abstract: A pressure sensor is provided with a means for efficiently removing heat from a circuit portion of a sensor die by providing an elastomeric member between a first surface of the sensor die and electrical leads. A thermally conductive, but electrically insulative, portion of the elastomeric member is disposed between the circuit portion of the sensor die and the leads and a means is provided for urging the first surface of the sensor die into thermal communicating contact with the thermally conductive portion of the elastomeric member. In addition, a selectively conductive portion of the elastomeric member is disposed between contact pads on the first surface of the sensor die and electrical leads encapsulated within a portion of the sensor housing. The elastomeric member is also provided with an opening formed therethrough and aligned with the diaphragm portion of the sensor die to permit the media to be in fluid communication with the diaphragm of the sensor die.

Abstract: A resistive strain gauge pressure sensor including upper and lower housings coacting to define a pressure chamber within the housing. A board member assembly 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. The board member assembly includes a relatively thin plate member, including a diaphragm portion, and a relatively thick support member bonded to the upper face of the thin plate member and including an annular portion positioned in surrounding relation to the diaphragm portion. The circuitry of the sensor is screen printed onto the lower face of the plate member and includes 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.

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 resistive strain gauge sensor of the type including a circuit board carrying circuitry, a diaphragm bonded to the circuit board, and strain gauge circuitry on the diaphragm. The strain gauge circuitry includes a plurality of leads defining free ends and the circuitry on the circuit board defines a plurality of leads defining free ends. The diaphragm is bonded to the circuit board by a frit layer and the frit layer includes voids which are in respective alignment with the free ends of the strain gauge leads and the free ends of the circuit board leads. A conductive epoxy is positioned in the voids in the frit layer to establish electrical communication between the strain gauge circuitry leads and the circuit board leads without the use of solder joints.

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 pressure sensor for detecting pressure in a combustion chamber of internal combustion engines has a housing, a sensor element composed of a piezoresistive material and arranged in the housing, a diaphragm, a punch introducing a pressure to be determined onto the sensor element and located between the diaphragm and the sensor element. The punch has a counterbearing, a hybrid has a base, and a preprocessing circuit has electronic components. The sensor element, the hybrid with its base and the electronic components of the preprocessing circuit are located on the counterbearing of the punch.

Abstract: A pressure-measuring head for measuring the pressure of a fluid consists of a membrane-like diaphragm (6), which separates a pressure chamber (4) from a reference chamber (7), to which the pressure-sensitive elements, e.g., thick-film resistors or strain gauges, are applied. Under the effect of the pressure in the pressure chamber, these pressure-sensitive elements perform a deflection which is proportional to the pressure occurring in the pressure chamber. An electric contact is switched during simultaneous displacement of the membrane (6) arranged in a sensor housing by a predeterminable distance (19) after a defined pressure value has been reached in the pressure chamber. A measuring head of such a design is also able to assume a swithing function without additional auxiliary energy, besides sending an electrically processable pressure signal.

Abstract: A silicon micro sensor including a silicon substrate, a support element formed over an etched portion of the silicon substrate and a sensor element formed on the support element wherein the support element has a double layered structure including a silicon oxide film formed on the silicon substrate using the thermal oxidization method and an aluminum oxide film formed on the silicon oxide film using the sputtering method.

Abstract: A pressure transducer employing at least one piezoresistive sensor fabricated from diamond. The diamond piezoresistive sensors are formed on a dielectric layer fabricated from silicon dioxide. The dielectric layer is formed on a silicon carbide force collector. In addition, the silicon carbide force collector may be fabricated from .alpha.-silicon carbide or p-type silicon carbide.

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 circuit for a pulse width modulating a sensor (12) has been provided. The circuit includes a first switch (22) for alternately coupling the sensor between first and second supply voltage terminals. The circuit also includes second (24) and third (28) switches and first and second capacitors for sampling the differential voltage appearing at outputs of the sensor when the first switch is in a closed state.

Abstract: An electrical circuit containing novel piezoresistive sensor is disclosed. The sensor is connected to a source of direct current, and a manometric pressure of at least about 15 p.s.i.g. is applied to the sensor.

Abstract: The formation of diaphragms by silicon wafer bonding provides for a structure having at least two such diaphragms with cavities in the wafers to which the diaphragm layer is bonded. Passageways through the wafers provide for communication of a fluid to the diaphragms. In some locations less than all of a plurality of diaphragms may be bonded to only one wafter having a cavity adjacent the diaphragm.

Abstract: A semiconductor pressure sensor according to the present invention comprises a semiconductor substrate having a first surface, a second surface opposite to the first surface and a recess formed in the first surface, the recess defining an interior surface including a bottom surface; and a diffusion region extending from the adjacency of the bottom surface to the second surface. A pressure-sensitive resistance of the semiconductor pressure sensor is formed in the vicinity of the bottom surface of a diaphragm. Therefore, the pressure-sensitive resistance can be formed so as to be brought into alignment with the position of the diaphragm after the formation of the diaphragm. Accordingly, a semiconductor pressure sensor, which does not cause a displacement in position between the diaphragm and the pressure-sensitive resistance and is excellent in accuracy, can be easily fabricated.

Abstract: A semiconductor pressure sensor according to the invention comprises a first semiconductor substrate and a second semiconductor substrate, disposed around the first substrate, so that signals obtained by the semiconductor pressure sensor under static or differential pressure conditions can be properly corrected and both static and differential pressures can be detected accurately and reliably measured on the same semiconductor substrates. Another object of the invention is provide a semiconductor pressure sensor which utilizes a single substrate with an aperture, which acts as a pressure overload stop mechanism, and which does not suffer from any effects of diaphragm deformation as a result of possible pressure overload.

Abstract: A semiconductor pressure sensor comprises a silicon substrate having a surface orientation of substantially (110), a diaphragm formed from the substrate, strain gauges disposed on the diaphragm, and a base joined with the substrate. The diaphragm has an octagonal shape whose sides are orthogonal to axis<100>, <110>, and<111>, respectively. This sensor causes substantially no output error and no fluctuation between output characteristics of the strain gauges irrespective of a change in temperature.

Abstract: A pressure sensor sub-assembly (18) has a solid-state sensing element (22) mounted on a laminated ceramic substrate (20) and has the electrical signal contacts (22a) on the sensing element electrically connected to connector pins (24) on the substrate. A manufacturing process can fabricate a batch of sub-assemblies on a substrate structure that is sub-divided to form the separate sub-assemblies. The sensor sub-assemblies can be tested, and graded, before or after the sub-division step, and then each mounted in a housing.

Abstract: A semiconductor pressure sensor includes a semiconductor pressure-sensing chip including a semiconductor body having a diaphragm that flexes in response to applied pressure, a strain gauge disposed in the diaphragm for altering an electrical signal in response to flexing of the diaphragm, and an amplifying circuit disposed in the semiconductor body outside the diaphragm and connected to the strain gauge for amplifying the electrical signal; a base supporting the semiconductor pressure-sensing chip; a package enclosing the semiconductor pressure-sensing chip and the base and having an opening providing access to the pressure-sensing chip; a plurality of leads penetrating the package and connected to the amplifying circuit; a substrate on which the package is mounted; and a gain-adjusting resistor disposed on the substrate opposite the package and electrically connected to the amplifying circuit for adjusting the gain of the amplifying circuit.

Abstract: A pressure transducer for measuring high differential pressure media in a harsh environment where a diaphragm assembly is mounted to an intermediate support number which is mounted to a main support member where the high pressure media impinges on the diaphragm to create a force opposing that provided by the diaphragm support structure thereby loading the diaphragm in compression. The strain sensitive piezoresistive elements are protected and sealed from the low pressure media by a passivation layer and electrical signal leads are attached to bonding pads formed on the diaphragm assembly which are sealed to the intermediate support member by a sealing cap.

Abstract: In an integrated multisensor used in a differential and static pressure transmitter, a pair of static pressure gages are formed on a static pressure detecting diaphragm and another pair of static pressure gages are formed at positions on a fixed portion which are near to the center of a differential pressure detecting diaphragm. The second term generated by a differential pressure appearing in a static pressure sensor is a function of a distance. Therefore, equal influence is exerted on each static pressure gage. Accordingly, by constructing a static pressure sensor so as to form a bridge circuit, a static pressure value free of the influence of a differential pressure can be detected, thereby making it possible to determine an accurate differential and static pressure.

Abstract: There is provided a pressure measuring sensor having a diaphragm including a peripheral fixing portion so formed as to be fixed to a pressure measuring sensor proper and be thick, a pressure receiving portion responsive to a pressure to be measured to move, and a strain causing portion responsive to the movement of the pressure receiving portion to cause strain, the pressure receiving portion having a shape so formed as to substantially perform the same function as a member having a high rigidity when moving in response to a change in the above described pressure to be measured, and the strain causing portion being substantially subject to bending stress in response to the movement of the pressure receiving portion moved according to the change in the above described pressure to be measured and thereby the strain causing portion providing a plurality of gauge resistors formed on the strain causing portion with tensile stress or compressive stress proportionate to the pressure to be measured.

Abstract: A pressure transducer is provided which incorporates numerous stress reducing characteristics. A pressure sensor is mounted to a ceramic plate with a buffer plate there between to isolate the pressure sensor from stresses that could be transmitted through the ceramic plate. The ceramic plate is necessary for the purpose of supporting a plurality of electronic components which comprise an amplification and compensation circuit. The ceramic plate is separated from all parts of its housing except a minimal central surface on a support boss which provides the support for the pressure sensitive device. Electrical communication between conductive paths on the ceramic plate and terminals extending through the housing is provided by flexible electrical conductors. A cover is attached to the housing with snap acting contact which further isolate the housing from the cap.

Abstract: A hollow body integrally formed of ceramic material and comprising a cavity formed therein and an integral connecting joint including a passage to said cavity at least one side of said cavity being confined by a diaphragm integral thereto. The ceramic hollow body may be produced by merging two green individual parts together followed by burning, the individual parts having large complementary contact surfaces with each other.

Abstract: A pressure transducer apparatus for use with low voltage supply source. A semiconductor piezoresistive strain gauge bridge provides an analog output of pressure variations which includes errors introduced by variations in the ambient temperature. A non-temperature-sensitive resistor across the bridge input is used to decrease the temperature dependent voltage change necessary for temperature compensation of the strain gauge bridge circuit output. Analog temperature adjustment means, provide as an output a current whose value changes concurrently and in direct proportion to the change occurring in the strain gauge bridge circuit current. An analog to digital converter has as its analog input the voltage output of the strain gauge bridge circuit, which is integrated over a first time period, and has as its reference input the temperature-adjusted output current from the analog temperature adjustment means which is integrated over a second time period.

Abstract: A pressure sensor for detecting pressure in a combustion chamber of internal combustion engines has a housing, a sensor element arranged in the housing and composed of a piezoresistive material, a diaphragm, and a punch arranged between the diaphragm and the sensor element and introducing a pressure to be determined onto the sensor element. The punch has an end facing the sensor element, at least the end of the punch is composed of relatively soft material.

Abstract: An automatic transducer selection system for fluid pressure measurement functions by using two or more transducers wtih different .Iadd.measurement .Iaddend.ranges .[.of accuracy.]. and also by incorporating comparator circuitry which automatically selects the transducer reading nearer to full scale. An electronic signal or output from the comparator is preferably nested such that a continuous voltage is generated in accordance with the fluid pressure being measured, this making the system appear to function as a single transducer with a wide .Iadd.measurement .Iaddend.range of .Iadd.high .Iaddend.accuracy.