Abstract: A polycrystalline pressure sensor is formed by depositing polycrystalline silicon piezoresistors on a polycrystalline sensing diaphragm. The piezoresistors are arranged in a wheatstone bridge configuration. During operation, an alternating differential signal is applied across the input of the wheatstone bridge. A measured voltage difference between the output terminals of the wheatstone bridge is used to detect imbalance in the electrical piezoresistors that corresponds to pressure applied to the sensor. Pressure is thereby measured.

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: The present invention provides a semiconductor pressure sensor having a glass base and a metal base bonded together satisfactorily so that a silicon diaphragm may not be affected by residual strain, and an intelligent differential pressure and pressure transmitting device employing the semiconductor pressure sensor.The semiconductor pressure sensor comprises a silicon diaphragm (1) provided with a strain-sensitive element, a glass or ceramic base (2) bonded to the silicon diaphragm (1), and a metal base (4) bonded to the glass or ceramic base (2) with a bonding glass (3). The thermal expansion coefficient of the metal base (4) at a temperature corresponding to the strain point of the bonding glass (3) is not greater than that of the glass or ceramic base (2).

Abstract: Pressure transducer circuitry accommodating pressure transducer variables for making pressure measurements in a living body. A microminiature piezoresistive pressure transducer has first and second variable resistive elements. The pressure transducer is characterized as having a pressure sensitivity ranging from 1.2 to 15 ohms per 1,000 ohms per 100 millimeters of mercury and a temperature characteristic greater than pressure sensitivity. Circuitry is coupled to the first and second variable resistive elements of the transducer including a known fixed resistive element. The known fixed resistive element is coupled to the first and second variable resistive elements for supplying a transducer excitation voltage through the known fixed resistive element to the first and second variable resistive elements. First and second amplifiers each having an input and an output are provided.

Abstract: In a pressure sensor, a metallic pressure introducing pipe is fit into the pressure receiving inlet formed in a metallic housing and fixed there by welding. The housing has a flange portion in its upper portion, and the flange portion is fixed to the outer wall of a tank which is an object to be measured so that the pressure sensor body is located inside the tank. A porous filter made of fluoroplastics is arranged adjacently to the atmospheric pressure introducing inlet. An adhesive tape which is removable is attached to the atmospheric pressure introducing inlet. The pressure sensor can realize stabilized maintenance and highly reliable airtightness for a sensor element, less limitation to sensor layout design in a small space and also can surely introduce air with no drop of water and dust into the sensor.

Abstract: A pressure sensor comprises a diaphragm mounted on a housing and subject to pressure. Stress sensitive resistors are connected to circuit traces on the diaphragm which in turn are wirebonded to a compensation IC. The IC is directly mounted on the diaphragm principally or wholly in an area which is not subject to flexing. A connector has a dome partially covering the diaphragm and holds terminal blades having ends extending away from the diaphragm and opposite ends carrying bond pads located adjacent the diaphragm. An opening in the dome permits wirebonder access to connect bond pads on the traces with terminal bond pads. A cover is installed over the connector and sensor.

Abstract: A semiconductor chip, which is preferably designed as a pressure sensor, has on its rear side one or more depressions in which the pressure is measured by correspondingly designed diaphragms which are coupled to piezosensitive circuits. The surface of the depressions and, optionally, the rear side of the semiconductor chip are coated with a protective layer which ensures that the semiconductor is protected from aggressive media. The protective layer thereby makes it possible to use the sensor universally in acids, lyes or hot gases.

Abstract: A method of fabricating a high pressure piezoresistive pressure transducer having a substantially linear pressure versus stress output over its full range of operation. The method involves bonding a carrier wafer having a dielectric isolating layer on one surface and a supporting member on the opposite surface, to a pattern wafer containing at least two single crystalline longitudinal piezoresistive sensing elements of a second conductivity. Both the pattern wafer and sections of the carrier wafer are etched leaving the piezoresistive sensing elements bonded directly to the dielectric isolating layer, and a diaphragm member having a deflecting portion and a non-deflecting portion. The diaphragm member is constructed to have an aspect ratio which is of the order of magnitude of one.

Abstract: A vertically integrated sensor structure (60) includes a base substrate (71) and a cap substrate (72) bonded to the base substrate (71). The base substrate (71) includes a transducer (78) for sensing an environmental condition. The cap substrate (72) includes electronic devices (92) formed on one surface to process output signals from the transducer (78). The sensor structure (60) provides an integrated structure that isolates sensitive components from harsh environments.

Abstract: A pressure difference measurement transducer with an inner housing divided into two parts transversely to its longitudinal axis has a central diaphragm bearing a pressure sensor clamped between the two housing sections. One housing section contains an electric lead-through in a bore, an external extension of which lies in an enlarged part of the bore. To simplify the electric lead-through in the manufacture of such a measurement transducer, the bore is arranged parallel to the longitudinal axis of the measurement transducer. At its end towards the other housing section the bore has an enlarged section and at its end away from the other housing section it becomes an outwardly directed transverse bore.

Abstract: A semiconductor pressure sensor of the invention comprises a silicon plate having a crystalline plane of (100) or (110), and the silicon plate comprises a diaphragm having the crystalline plane of (100) or (110), and a base surrounding said diaphragm. Further, a plurality of piezoresistor elements formed on the diaphragm. An area S (m.sup.2) and a thickness t (m) of said diaphragm satisfies a following relation:S/t.sup.2 <(.epsilon./(P.sup.3/2 K)).sup.1/3,where P (kPa) denotes applied pressure and .epsilon. (%) denotes a desired error of linearity of pressure, andK=1*10.sup.-4 (kPa).sup.

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 pressure detector comprises a pressure sensitive element composed of a semiconductor substrate having at least four gauge resistances and outputting signal in response to a pressure. A pressure transmission member is provided on the surface having the gauge resistors of the pressure sensitive element, for transmitting the pressure to the pressure sensitive element. Taking a crystal face of (110) as the face orientation of the pressure sensitive element, a bridge circuit is constructed by disposing a pair of gauge resistors in the direction of <110> of the crystal axis, disposing another pair of gauge resistors in the direction of <100> of the crystal axis and by connecting them each other. The bridge circuit is located within a pressurized surface which the pressure transmission member presses. Further, temperature compensating resistors are disposed in the direction of <100> of the crystal axis so as to be located also within the area of the pressurized surface.

Abstract: A pressure transducer for use with a pneumatic tire monitoring system includes a non-conductor resilient layer and a piezo-resistive/variably conductive layer having a composition which provides substantially constant resistant while under a substantially constant load. In a preferred embodiment, the piezo-resistive/variably conductive layer includes N-type semiconductor material, molybdenum disulfide, titanium, bismuth oxide, and alkyd or silicone binder. The transducer also includes conductive elements which are attached to a nonconductive substraight and electrically insulated from each other. The piezo-resistive/conductive layer contacts at least two of the conductive elements with a surface area which is responsive to a change in pressure so as to produce a variable resistant/conductives between the conductive elements. In one embodiment, the piezo-resistive/conductive layer is hemispherically shaped and divided to produce two independent sensing transducers.

Abstract: A high pressure sensor structure (11, 111, 211) includes a housing (12, 112, 212) having an upper cavity portion (13, 113, 213) and a lower cavity portion (16, 116, 216). A diaphragm (18, 118, 218) separates the upper cavity portion (13, 113, 213) from the lower cavity portion (16, 116, 216). A semiconductor chip (26, 126, 226) is attached to the upper surface of the diaphragm (18, 118, 218) within the upper cavity portion (13, 113, 213). The diaphragm (18, 118, 218) has a thickness (21, 121, 221) and an exposed width (23, 123, 223) such that the semiconductor chip (26, 126, 226) generates a measurable output signal when the lower surface of the diaphragm (18, 118, 218) is exposed to a high pressure environment.

Abstract: A novel pressure measurement apparatus for measuring fluid pressures generated within a fluid passageway is disclosed. The apparatus includes a semiconductor pressure transducer which is mounted to a chip carrier comprised of a ceramic substrate layer. The semiconductor pressure transducer is reverse mounted to the substrate layer by way of a series of electrically conductive epoxy bond points. The semiconductor pressure transducer is enclosed within a gel cap containing an incompressible gel medium. Fluid pressures generated within the fluid passageway are communicated to the transducer via the gel medium.

Abstract: A differential amplifier circuit that exhibits low temperature drift and a wide dynamic range includes a differential amplifier having first and second input terminals, first and second circuit nodes operatively connected to the first and second input terminals, respectively, a differential input signal pair, first and second sampling capacitors and a switching circuit. During a first operational phase, the switching circuit connects, a first plate of the first capacitor to a first input signal of the differential input signal pair, connects a first plate of the second capacitor to a second input signal of the differential input signal pair, and connects second plates of the first and second capacitors to a reference voltage.

Abstract: A magnetoresistive sensor may be constructed with material having a perovskite-like crystal structure and an increased magnetoresistive effect. The material is based on the composition (A1).sub.1-x (A2).sub.x MnO.sub.z, with A1 (trivalent) selected from Y, La, or a lanthanide, A2 (bivalent) from an alkaline-earth metal or Pb, and with 0.1.ltoreq.x.ltoreq.0.9 and 2.0.ltoreq.z.ltoreq.3.5. The sensor contains a layer system with at least two layers with different materials, but in each case in the context of the aforesaid composition, which is selected so that the temperature correlation of the electrical resistance is relatively small. The two layers of the layer system can also be united into a single layer structure with a concentration gradient.

Abstract: A transducer housing for mounting a port in a combustion chamber has a metal diaphragm exposed to the combustion gasses. The pressure of the combustion gasses deflects the diaphragm which locally deflects a simply supported beam. The beam is formed of refractory material having epitaxially grown crystalline piezoresistors formed on one surface of the beam and connected in a bridge circuit. Noble metal foil leads connect to the piezoresistors to form the bridge and provide attachment pads. The pads are noble metal welded to other noble metal foil pads provided on a ceramic substrate to form a sensor subassembly for mounting adjacent the diaphragm to form a transducer.

Abstract: Piezoresistive pressure transducer circuitry accommodating transducer variables comprising microminiature pressure transducer having first and second variable resistive elements each having first and second ends, circuitry coupled to the first and second resistive elements of the transducer including third and fourth fixed resistive elements each having a first and second ends, means interconnecting the first ends of the first and second resistive elements, means interconnecting the second ends of the first and third resistive elements, means interconnecting the second ends of the second and fourth resistive elements, means interconnecting the first ends of the third and fourth resistive elements, means for supplying excitation to the first ends of the third and fourth resistive elements, first amplifier means having an input coupled to the means interconnecting the second ends of the first and third resistive elements, second amplifier means having an input coupled to the means interconnecting the second end

Abstract: The invention relates to a process for making an oblique-sided recess in a substrate in which areas of the surface of the substrate corresponding to the recess to be made are covered with an etching mask which is not attacked by an isotropic etching liquid, whereupon an isotropic etching is effected. In order to be able to make oblique sides of very slight slope with such a process, a layer (4) which is removable by the isotropic etching liquid is applied to the surface areas (3) of the substrate (2) before the application of the etching mask (5).

Abstract: A pressure sensor is capable of detecting a certain pressure and an atmospheric pressure individually and independently in real time, with miniaturization and light weight. This is attained by providing a pressure sensor comprising a first pressure sensor; and an atmospheric pressure sensor. Each sensor includes a pressure-sensitive element and a circuit for amplifying an output signal from the pressure-sensitive element. The amplifying circuit for the first pressure sensor, and the pressure-sensitive element and the amplifying circuit for the atmospheric pressure sensor are provided on the same chip. The amplifying circuit compensates for nonuniformity in characteristics of the pressure-sensitive element due to temperatures.

Abstract: A sensor for detecting physical amount in which a gauge resistance value is made not to change even when a wiring material presents a yield phenomenon by wiring a wiring material Such as aluminum presenting a yield phenomenon by thermal stress in a stress insensitive direction of a piezogauge.

Abstract: A differential pressure transmitter detects a differential pressure condition of a fluid by means of a semiconductor sensor. First and second seal diaphragms are provided in a member which constitutes the differential pressure transmitter, to form first and second pressure receiving chambers. An overload protection diaphragm and first and second damper chambers are provided at positions close to the first and second pressure receiving chambers. Also, there are provided a passage for connecting the first pressure receiving chamber and the first damper chamber, a passage for connecting the second pressure receiving chamber and the second damper chamber, and passages for connecting the first and second damper chambers respectively with the semiconductor sensor. Even when a change is caused in the temperature of a processed fluid to be detected, the differential pressure transmitter quickly detects the temperature change, so that a differential pressure of the processed fluid can be measured with high accuracy.

Abstract: A method is disclosed for micromachining the surface of a silicon substrate which encompasses a minimal number of processing steps. The method involves a preferential etching process in which a chlorine plasma etch is capable of laterally etching an N+ buried layer beneath the surface of the bulk substrate. Such a method is particularly suitable for forming sensing devices which include a small micromachined element, such as a bridge, cantilevered beam, membrane, suspended mass or capacitive element, which is supported over a cavity formed in a bulk silicon substrate. The method also permits the formation of such sensing devices on the same substrate as their controlling integrated circuits. This invention also provides novel methods by which such structures can be improved, such as through optimizing the dimensional characteristics of the micromachined element or by encapsulating the micromachined element.

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 semiconductor device comprises a piezoresistive pressure sensor (12), which has a membrane (14), which is constituted by a conducting epitaxy layer (16), which is applied to a conducting semiconductor substrate (18) of the opposite conductivity. On the outer surface (20) of the membrane facing away from the semiconductor substrate (18) at least one piezoresistor (22) is incorporated. Between the semiconductor substrate (18) and the epitaxy layer (16) an annularly structured intermediate layer (28) is incorporated, which defines a region (26'), adjoining the inner surface (24) of the membrane, of an opening (26) extending through the semiconductor substrate (18). This opening (26) is produced by anisotropic semiconductor etching, the intermediate layer (28) having a conductivity which is opposite to that of the semiconductor substrate so that this intermediate layer (28) functions as an etch stopping means and is not attacked by the etchant.

Abstract: In a pressure sensor, a force is transferred via a pressure plunger end made of relatively hard material onto a measurement element including a sensor membrane on a support. The sensor membrane is part of a micromechanical arrangement made of silicon. A metal structure made of a metal of lower hardness compared with the hardness of the material of the pressure plunger end is applied onto the sensor membrane. This metal structure can be impressed and plastically deformed with increased force by the contact surface of the pressure plunger end, in such a way that conforming contact of the contact surface is achieved, and potential angular errors are compensated for.

Abstract: A form of pressure sensor diaphragm and method of making that allows for the formation of long rectangular plate structures in semiconducting material, especially Silicon. A plurality or multiplicity of sensors may be constructed on a single chip, thus providing for absolute and relative sensing of pressure on a single device.

Abstract: A multi-function differential pressure sensor includes a semiconductor chip, a stationary base having a joining portion joined to a thick wall portion of the semiconductor chip, and a housing joined to the stationary base. The semiconductor chip is provided with a differential pressure detection unit, a static pressure detection unit, and a temperature detection unit. The joining portion of the stationary base is not thicker than the semiconductor chip. The stationary base has one or more thin wall portions located, in a plan view, within a circular pressure sensitive diaphragm of the semiconductor chip.

Abstract: A media-isolated differential pressure sensor apparatus and corresponding method combines a first signal (207, 209) provided by a first pressure sensor (101), indicative of a difference between a first pressure and second pressure applied across the first pressure sensor, and a second signal (213, 215) provided by a second pressure sensor, indicative of a difference between the second pressure and a third pressure applied across the second pressure sensor (103) to form a differential pressure sensor. Responsive to a pressure span the first signal (207, 209) responds with a slope response different than a slope response of the second signal (213, 215). A slope adjustment circuit (217) enables an adjustment of the slope response of the first signal (207, 209) to correspond to the slope response of the second signal (213, 215), and provides a slope adjusted first signal (221) dependent on the adjusted slope response.

Abstract: A measuring and controlling system is provided which has a control function as well as a measurement function to perform the measurement and control of fluid amounts such as the flow rate, pressure, liquid level, weight and so on by itself in the same field. A pressure receiving unit is directly mounted on a pipe or a container, in which a fluid under measurement exists, in order to detect the temperature, differential pressure and static pressure of the fluid under measurement independently of each other. Means for storing the characteristic of fluids under measurement is provided such that the mass flow rate, weight and liquid level can be calculated.

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 drive circuit for a strain sensor includes a Wheatstone bridge having semiconductor strain gauges. A temperature-dependent voltage generator generates a voltage having a predetermined ambient temperature dependency characteristic, a constant voltage generator generates a predetermined constant voltage, and a proportional voltage generator generates a voltage proportional to an externally supplied power source voltage. A voltage processor receives and arithmetically processes output voltages of the temperature-dependent voltage generator, the constant voltage generator and the proportional voltage generator to generate a bridge drive voltage which changes from a mid value to a predetermined voltage depending on a temperature proportional to the power source voltage. In an amplifier circuit for amplifying a strain output signal from the Wheatstone bridge, both the potentials across an AC coupling capacitor are kept to be equal at a steady-state operation.

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 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: 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 dual absolute pressure sensor independently converts first and second external pressures to first and second electrical signals respectively. A package body has first and second openings for receiving the first and second external pressures to outside surfaces of first and second sensor die attached to opposite surfaces of an internal glass substrate that separates the first and second openings. The first sensor die includes a first cavity having a reference pressure to measure against the first external pressure and develop a first differential pressure. A first piezoelectric network converts the first differential pressure to the first electrical signal representative of that pressure. The second sensor die includes a second cavity having a reference pressure to independently measure against the second external pressure and develop a second differential pressure. A second piezoelectric network converts the second differential pressure to the second electrical signal representative of that pressure.

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 semiconductor pressure sensor includes a semiconductor substrate, a pressure detection gage, and a temperature detection gage. The semiconductor substrate has a thin portion formed in its central portion and a thick portion formed on an outer periphery of the thin portion. The pressure detection gage is formed on one surface of the thin portion of the semiconductor substrate and serves as a piezoelectric resistive region. The temperature detection gage is constituted by a piezoelectric resistive region formed by connecting a plurality of pairs of orthogonal minute line segments in a zigzag form. The two minute line segments of each pair are formed on a surface of the thick portion of the semiconductor substrate in crystallographic directions in which piezoelectric resistance coefficients are minimized.

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 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 pressure sensor including a plate-shaped metal substrate; a glass layer provided on a surface of the metal substrate and mainly containing a partially devitrified enamel composition; a resistor element which is provided on a surface of the glass layer and has an electric resistance changed in accordance with the degree of strain thereof; and a pair of electrodes connected to the resistor element. The resistor element is provided so as to receive a stress, a pressure, or a load applied perpendicularly to a surface thereof. Alternatively, both surfaces of the metal substrate are provided with glass layers, respectively, and the resistor element is provided on one of the glass layers.

Abstract: A semiconductor strain sensor includes a base, a peripheral section, a central section and a flexible beam. The peripheral section is bent to the base. Bonding strain is generated at a bonding portion between the base and the peripheral section. The central section extends from the peripheral section. The flexible beam extends from the central section and includes a strain detecting element. The strain detecting element changes its electric characteristic when strain is applied thereto. A thickness of the flexible beam is thinner than that of the central section. The bonding strain is transmitted from the bonding portion to the strain detecting element through a transmission path. The transmission path is bent. The bonding strain is attenuated because it is dispersed at a bending portion of the transmission path. The sensor accurately detects the strain to be detected without a bad influence of the bonding strain.

Abstract: A semiconductor type differential pressure measurement apparatus is disclosed comprising a measuring diaphragm having its periphery fixed, and two measuring chambers, each having a predetermined spacing along both surfaces of the measuring diaphragm, and which detects differential pressure within allowable limits of measurement. When an overpressure is applied, the diaphragm is stopped by a wall of a measuring chamber to prevent the diaphragm from being damaged by overpressure, so that no additional mechanism is required to prevent damage from overpressure. One embodiment utilizes an additional chamber and overhang to reduce overpressure. Another embodiment utilizes a measuring chamber having the two sides of the diaphragm exposed to the ambient to eliminate need for a pressure resistant casing. In a further embodiment, injected impurities serve as a terminal.

Abstract: A pressure transducer comprises a polycrystalline diamond diaphragm (39), produced by use of a chemical vapour deposition technique, on a support (33). The diaphragm (39) can deflect in response to variations in pressure. A single optical fibre interferometer (36, 32) is used for detecting and measuring the deflection of the diaphragm (39) (FIG. 3).

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: Microminiature pressure transducers are formed on semiconductor substrates such as silicon and include a membrane which spans a cavity over the substrate, with the membrane being mounted to and sealed to the substrate at the peripheral edges of the membrane. The bottom of the cavity forms an overpressure stop to prevent over deflections of the membrane toward the substrate. An overpressure stop formed as a bridge of a material such as nickel extends above the membrane and is spaced therefrom to allow the membrane to deflect freely under normal pressure situations but prevent over deflections. The thickness of the polysilicon membrane and the spacing between the membrane and the overpressure stops is preferably in the range of 10 micrometers or less, and typically in the range of one micrometer. The overpressure stop bridge is formed utilizing deep X-ray lithography to form a well-defined bridge structure.