Abstract: A pressure sensing device including a single crystal of silicon configured to have a diaphram portion, a frame portion and associated circuitry formed on the crystal is described. Piezo-resistive elements on the boundary of the frame and the diaphram portions of the crystal respond to changes in pressure. The piezo-resistive elements, associated elements, and connecting conducting paths are formed by thin film and/or doping techniques to provide a monolithically integrated circuit. The elements are passive and require only application of input voltages and detection of output signals to provide an operative component. Trimmable resistors are provided for compensation and resistive adjustment, and at least one resistive element provides temperature compensation.

Abstract: Disclosed is a pressure transducer comprising a pressure sensitive silicon die having a front side exposing piezoresistive means and comprising means for flip-chip mounting the die to a pressure vessel. The transducer further comprises a pressure vessel having an aperture, the pressure vessel comprising means for flip-chip mounting the die over the aperture. The die is flip-chip mounted over the aperture in the pressure vessel, and there is a hermetic seal between the pressure vessel and the die.

Abstract: A solid state semiconductor pressure sensor is described in which the pressure sensor element is protected from the ambient whose pressure is being measured by a combination of a pressure transfer medium and a thin covering membrane. A method is described for applying the thin covering membrane so as to substantially avoid entrapment of air or formation of voids in the pressure transfer medium which would degrade the performance of the sensor. The pressure transfer medium is a gel-like material such as a silicone rubber. The membrane is chosen to be substantially impermeable to the ambients being measured and sufficiently flexible to avoid attenuation of the input pressure signal. The membrane is cast in place by applying a thin liquid coating or a heat deformable film over the pressure transfer medium and then converting it into a thin solid membrane stuck to the pressure transfer medium and the pressure sensor body.

Abstract: A pressure transducer, which includes a silicon diaphragm with ion-implanted resistors in Wheatstone Bridge configuration and in insulating layer covering the diaphragm, is provided with temperature compensation for differences in thermal expansion coefficients of the layers by depositing a layer of aluminum onto the central portion of the diaphragm.

Abstract: A pressure pick-off for generating electrical signals comprises a reference pressure chamber which is oxygen-free, at least one pressure dependent deformable membrane closing the reference pressure chamber from a medium under pressure and supporting at least one electric sensor element, and a conductor located in the reference pressure chamber and connectable with a measuring current circuit, the conductor being formed so that during a leakage in the reference pressure chamber it is oxidized by penetrated oxygen so that it is electrically interrupted.

Abstract: A pressure transducer having a magnetoresistive element and a magnet displaced with a diaphragm. A magnet supporting device is mounted on an element supporting device both for slidable movement in the displacement-direction of the magnet and for rotatable movement about an axis in the direction, so that the pressure transducer is capable of having a O-point adjustment and a magnetic sensitivity adjustment made independently of each other without interaction between the two when the transducer is assembled.

Abstract: A pressure transducer comprises a movement which has separate span and set-point calibrations. A subsequent calibration of the span does not adversely influence a previous calibration of the set-point. Sensed pressure is reflected as arcuate motion of a crank mechanism along a resistor. The span calibration is performed by adjusting the position of the resistor in relation to the crank's pivot. The pivotal mounting of the crank is provided by a pivot member disposed within a slot. Adjusters in transverse slots which intersect the pivot mounting slot act upon the pivot member to establish the set-point calibration. The transducer is especially well suited for fabrication and calibration by automated equipment.

Abstract: A pressure transducer with a diaphragm coupler at one end and a sensing element at the other end connected by a capillary tube. The sensing element includes a cap member having a deformable surface including a top wall forming a thin diaphragm having a diametrically disposed raised beam extending across the top surface and having a gage received surface for receiving a plurality of strain gages. The deformable top wall surface has indentations therein on either side of and extending longtudinally of the raised beam to reduce tension forces across the diaphragm and improve linearity of the diaphragm.

Abstract: A pressure sensor includes a metal diaphragm provided at the end of a pressure introduction portion, a glass layer bonded to a surface of the metal diaphragm opposite to the pressure introduction side thereof, and a semiconductor chip acting as a semiconductor strain gauge bonded to the surface of the glass layer.

Abstract: Disclosed is a pressure transducer package comprising a housing and a substantially cylindrical chamber formed into the housing, a first end of the chamber comprising a substantially flat surface. The package further comprises a substantially cylindrical interface plate having first and second substantially flat end surfaces, one end surface of the interface plate facing the first end surface of the chamber. The package further comprises a pressure transducer comprising a pressure sensitive silicon die mounted to a substantially cylindrical support member. The support member comprises first and second substantially flat end surfaces. The other end surface of the interface plate faces one end surface of the support member. The housing comprises plug apparatus for hermetically sealing the chamber, the plug apparatus having a substantially flat surface forming a second end of the chamber.

Abstract: A pressure transducer with a diaphragm coupler at one end and a sensing element at the other end connected by a capillary tube. The sensing element includes a cap member having a deformable surface including a top wall forming a thin diaphragm having a diametrically disposed raised beam extending across the top surface and having a gage receiving surface for receiving a plurality of strain gages.

Abstract: A transducer employs two separate pressure input ports. Each port is associated with a separate metal diaphragm behind which diaphragm is secured a transducer structure having a cup-shaped silicon pressure diaphragm which is retained within a hollow of the transducer which is oil filled. One transducer structure is a half bridge array and monitors the main pressure applied to the positive port. A full bridge is formed by two resistors associated with the positive port and two resistors in an array associated with the other port which is the negative port. The resistors in the array at the negative port are selected to be larger in magnitude than those at the positive port and exhibit a greater sensitivity per unit of applied pressure.

Abstract: A pressure sensor comprising an air-tight container, enclosing water vapor therein, which elastically deforms depending upon a variation in the external pressure to result in a variation in the content volume thereof, a moisture sensor disposed within the container, and a moisture detector which electrically detects a variation in the amount of moisture to be absorbed by the moisture sensor depending upon the internal partial pressure of the water in the container due to the elastic deformation of the container.

Abstract: A semiconductor pressure sensor wherein a semiconductor chip of diaphragm type is supported by a mount plate through a thin tubular supporting member or a pressure inlet tube having a coefficient of thermal expansion similar to that of a substrate constituting the semiconductor chip. The semiconductor chip is fixed to the thin tubular supporting member or the pressure inlet tube by means of a bonding material, and the thin tubular supporting member or the pressure inlet tube is fixed by means of a bonding material having a high bonding strength with respect thereto, thus absorbing thermal stress produced due to the difference in coefficient of thermal expansion.

Abstract: A pressure transducer for in particular the measurement of relatively high pressures in the range of 10,000-50,000 psi and including an elongated frame having a capillary tube extending therethrough and employing a coupler at one end of the frame for sensing input pressure. A sensing member is provided disposed about the capillary tube at the other end of the frame and has, defined with the capillary tube, a sensing chamber in communication with the capillary tube. A recess is provided in the sensing member defining a relatively thin wall adjacent the annular sensing chamber. This wall has a pressure responsive sensing surface that extends substantially parallel to the capillary tube length and upon which strain gages are secured. A method as described for securing the capillary tube with the sensing member in a liquid tight manner.

Abstract: There is disclosed apparatus and methods of fabricating a piezoresistive semiconductor structure for use in a transducer. According to one method, a layer of silicon dioxide is grown over the surface of a first semiconductor wafer which is designated as a carrier wafer. A layer of glas is then formed on the top surface of the carrier wafer over said layer of silicon dioxide. A second wafer has diffused therein a high conductivity semiconductor layer which is diffused on a top surface of a sacrificial semiconductor wafer. The first and second wafers are then bonded together by means of an electrostatic bond with the high conductivity layer of the sacrificial wafer facing the glass layer of the first wafer. After securing the wafers together, one may etch away the remaining portion of the sacrificial wafer to provide a high conductivity resistive layer which is secured to the glass layer of the first wafer and is patterned to form a resistive network using standard photolithographic making.

Abstract: A flange provided on a tubular metallic member coupled by glass bonding to the glass base to which the strain guage is fixed is made to contact with a receptacle step formed in a housing section of a housing, while pressurizing a metal ring in the housing section to cause plastic deformation of a part of the ring material into a coupling groove formed in the inner peripheral surface of the housing section, thereby coupling the metal ring and the housing.

Abstract: In a differential pressure transducer having isolation diaphragms on opposite sides of a sensing diaphragm, the isolation diaphragms are made highly compliant, are radially prestressed and are bowed outwardly relative to closely spaced backup surfaces by oil pressure. Using very small interior cavities and a substantially stiffer sensing diaphragm differential process pressures induce linear deflection of the sensing diaphragm.

Abstract: Parameter sensors and monitors are described incorporating one of a variety of parameter responsive structures constructed and arranged for expansion and contraction causing a component of motion and displacement along at least one direction in response to variations of a selected parameter. A reference mounting supports the parameter responsive structure and either a magnet element or Hall effect transducer is secured relative to the reference mounting or housing in alignment with a selected direction of a component of motion and displacement caused by expansion and contraction of the parameter responsive structure. The other of said magnet element and Hall effect transducer is mounted for relative displacement along said selected direction in response to expansion and contraction of the parameter responsive structure.

Abstract: Disclosed is a pressure transducer comprising a pressure sensitive silicon die having a front side exposing piezoresistive means and a back side for receiving pressure from a pressure medium. The transducer further comprises a pressure vessel having an aperture and apparatus including a hermetic seal for mounting the die with the front side of the die facing the aperture. In this manner, the die is compressed toward the pressure vessel when positive pressure is applied to the back side of the die by the pressure medium.

Abstract: A low cost piezoresistive pressure transducer utilizing premolded elastomeric seals and adapted for automatic assembly, and a method of producing the transducer. A piezoresistive stress sensitive element in the form of a diaphram of semiconductor material having a thickened rim is held at its rim between a pair of premolded elastomeric seals in a thermoplastic housing. Electrical connections with external circuitry are made with strain relief jumpers which connect conductive regions on the element outside the seals to conductors which pass through the housing wall.

Abstract: A circular diaphragm with an annular thin portion has a smooth front surface, and coaxial but spaced inner and outer cylinders are secured to a rear surface of the diaphragm across said annular thin portion. Opposite edges of a rectangular strain member which is operatively connected to the disphragm through the inner cylinder are secured to a free end of the outer cylinder.

Abstract: A sensor having a silicon die having a central region and a flexible annular sensing portion surrounding the central region. The sensor has apparatus carried by the central region of the die for limiting the movement of the central region in each of two opposite directions.

Abstract: A pressure responsive assembly including an actuator rod coupled to a pressure source through a rolling type diaphagm. The other end of the actuator rod is connected to a wiper assembly. A first part of the wiper assembly contacts a coil of resistance wire to provide a first signal indicative of the pressure. A second part of a wiper assembly moves into and out of contact with a switch contact pad as the sensed pressure crosses a predetermined threshold value.

Abstract: A semiconductor strain-gage is disposed in a recessed chamber of a housing. A step is provided in the recessed chamber. Minute grooves are provided in the inner peripheral portion of the step. An outer periphery of a metal disk with a pressure introducing bore is clamped to the minute grooves by means of plastic deformation thereof, after the seal diaphragm is disposed on a planer portion of the step, whereby the seal diaphragm closes the recessed chamber harmetically.

Abstract: In a semiconductor pressure transducer in accordance with the present invention, an oxide film is formed on a semiconductor base having a strain gauge resistor element for the purpose of protecting the strain gauge resistor element. Over the oxide film, a conductive metal film is formed which does not overlap with the strain gauge resistor element through said oxide film.

Abstract: A differential pressure transmitter includes a housing, a first chamber within the housing for receiving an input pressure to be sensed and a second chamber for receiving a transmitter adapted to generate an electrical signal representative of the input pressure. The chambers are separated by a continuously formed, highly resilient diaphragm. A reaction member embodied as a resilient spring is disposed in the second chamber for sensing a position of the diaphragm resulting from the magnitude of the differential pressure thereacross. The reaction member has a magnetized structure mounted thereon which coacts with a Hall effect transducer embodied in the transmitter for detecting the relative position of the magnetized structure and therefore of the diaphragm and responsively generating an electrical signal. The signal may be utilized for positioning actuator controlled dampers within a VAV system duct.

Abstract: A pressure converter which comprises a cylindrical main body consisting of an outer casing portion and an inner casing portion, said outer casing having a pressure inlet and being divided by a diaphragm into an air-tight chamber above the diaphragm and an operation chamber below the diaphragm, a piston supported by a pair of annular spring plates within the operation chamber for vertical movement and having an engaging member provided at one end, a stopper interposed between the spring plates, a magnetic resistance provided in a lower portion of the operation chamber to produce output voltage which varies depending upon the position of a permanent magnet positioned on a movable member in opposition to the magnetic resistance and a spring anchored to the inner casing portion and the movable member to normally bias the movable member to engage the piston.

Abstract: A diaphragm-type pressure sensor employs a monocrystalline wafer as a pressure-responsive diaphragm. The wafer has a central active area surrounded by a first bonding area on one side and a second bonding area on the other side. The first bonding area is attached by a first layer of bonding material to a base, and the second bonding area is attached by a second layer of bonding material to a cap. The inside diameter of the first bonding layer is greater than the inside diameter of the second bonding layer by an amount of at least approximately six times the thickness of the diaphragm. This disparity between the respective inside diameters of the two bonding layers results in the relief of radially-directed tensile loading on the first bonding layer when a pressure to be measured is applied to the first side of the diaphragm. Consequently, the probability of a fracture occurring in this bonding layer is minimized.

Abstract: An etch stopped layer portion overlying a (100) or (110) major face of a diamond cubic semiconductor material is undercut anisotropically etched by orienting a side edge of the etch stopped layer portion which is to be undercut, at an angle to the most nearly parallel {111} trace on the (100) or (110) face. The etch time is further reduced by slotting through the etch stopped layer with slots oriented at an angle to the {111} traces on the underlying (100) or (110) face. Undercut bridge structures are formed by undercutting quadrilateral etch stopped layer portions from opposite sides of the quadrilateral or from the sides plus slots forming diagonals of {111} trace quadrilaterals having combined areas coextensive with the area to be undercut.

Abstract: Three dimensional single crystalline structures, such as folded cantilever beams supported from a frame and supporting a central structure free to move relative to the frame, are fabricated by anisotropically etching through openings in etch stop layers on opposite sides of the substrate wafer. The openings are patterned and aligned so that the etch stop layers are undercut to define etch stop portions interconnected by unetched substrate material.

Abstract: A disposable strain gauge pressure sensor providing reliable electrical isolation even at defibrillation voltages in the measurement of biological fluid pressures is produced by floatingly mounting a glass plate on a closed cell, fluid-impervious foam pad within a firm but not totally rigid plastic housing. The glass plate has a thin glass diaphragm integrally formed therein which carries the strain gauge element. Openings in the foam pad and the housing allow a fluid contained in a fluid dome on the outside of the housing to bathe the side of the glass diaphragm opposite that on which the strain gauge element is mounted. The glass plate, foam pad, and housing are bonded together in fluid-tight relationship so that fluid cannot reach anything within the housing other than the glass diaphragm. The housing is preferably transparent to allow observation of the diaphragm during operation.

Abstract: A combustion pressure sensor has a first diaphragm adjacent a combustion region for deflecting in response to the magnitude of adjacent pressure. A second diaphragm is spaced from the first diaphragm and deflects as a function of the deflection of the first diaphragm. The second diaphragm is adapted to generate a signal indicative of the deflection of the second diaphragm. A force transmitting means between the first and second diaphragms transmits movement of the first diaphragm to the second diaphragm and reduces heat transfer from the first diaphragm to the second diaphragm.

Abstract: A pressure measuring device wherein a housing (1) includes a pressure sensor (2) in a pressure chamber (4) and an electronic circuit (14) in a non-pressurized chamber (6). Borings (7) extend between pressure chamber (4) and non-pressurized chamber (6) and accommodate contacts that electrically connect pressure sensor (2) and electronic circuit (14). A pressure membrane (3) cooperates with housing (1) to further define pressure chamber (4) and isolate the device from the fluid system. Pressure chamber (4) is filled with a medium that transmits the system pressure to pressure sensor (2). Pressure sensor (2) measures the pressure and provides an output signal to electronic circuit (14).

Abstract: A pressure transducing device in the form of a beam includes a monolithic chip of silicon or similar material which is mechanically supported at and near its two opposed ends and unsupported in a flexible region between the two ends. The flexible, unsupported region is one of maximized sensitivity to stresses produced by deflection or flexing of the beam due to, e.g., a differential pressure applied across it. An integral, pressure-responsive diaphragm is formed in the supported area of the chip near one of its mechanically-supported ends. This area of the chip is relatively insensitive to stresses produced by beam flexing or deflection; rather, it responds to stresses produced by a pressure (e.g., a static pressure) applied directly to its surface. A first set of strain gauges is provided in the flexible chip region, and a second set on the surface of the integral diaphragm.

Abstract: A differential pressure transmitter for process fluids is of the kind having a measuring transducer with a closed cell containing a filling liquid and a measuring diaphragm on both sides of which are arranged resistive, capacitive or inductive elements which are capable of converting a diaphragm deflection induced by differential pressure applied to the cell into electrical quantity changes. Inside the cell is provided at least one pressure sensitive component which is subjected to the pressure (s) of the filling liquid and is capable of providing an electrical output in accordance with the pressure values. This component is preferably a pasted carbon resistor, which permits output processed signal compensations in an electronic processing circuit to be made so as to minimize the effects of static pressure changes.

Abstract: A transducer is provided for measuring very low pressures, on the order of 1.5 inches of water. A fluid-tight elastomeric barrier formed with convolutions to allow relatively large linear deflections is bonded to stiff sensing element of minimum mass, the deflection of which is sensed by strain gauges mounted on a neck connecting the sensing element to the transducer housing.

Abstract: A transducer for sensing pressure formed of a single crystal semiconductor chip having a cavity formed in one surface, wherein a tube to communicate pressure to the cavity surrounds the cavity, wherein pressure measuring sensors are disposed opposite the cavity and wherein additional pressure-responsive sensors are disposed on the chip to provide a signal for compensating for zero shift temperature and pressure induced signals generated by the measuring sensors.

Abstract: A transducer for establishing an output voltage proportional to an input fluid pressure supplied thereto. The transducer has a resistor with a voltage selector movable in electrical contacting engagement therewith to establish the output voltage. A piston actuates the voltage selector to its electrical contacting engagement with the resistor to establish the output voltage in response to the input fluid pressure acting on a diaphragm arranged in driving engagement with the piston.

Abstract: A pressure sensor converts fluid pressures into electrical signals by the deformation of a diaphragm. The pressure sensor is comprised of a strain gauge which includes resistance body of amorphous metal material which may be formed directly on the diaphragm by means of a physical vapor deposition process.

Abstract: An electrically isolated semi-conductor transducer and method of making the same wherein a unitary piece of silicon material having opposed flat surfaces is carved out about a central portion thereof through one flat surface forming a toroidally-shaped cavity having curved bottom surfaces partway through said material surrounding a push rod having an upper flat surface lying in the same horizontal plane as the remainder of said carved out flat surface. The upper flat surface of the push rod and the curved carved surfaces surrounding the push rod are etched exposing the silicon material. A plurality of strain gages are provided on the opposite flat uncarved surface of said silicon material. These strain gages may include four diffused silicon strain gages at spaced locations along said uncarved surface.

Abstract: A pressure sensor converts a fluid pressure into electric signals by means of a deformation of a diaphragm. The pressure sensor includes a resistance body means made of an amorphous metal material used as material for a strain gauge. The resistance body means has resistance body elements composing each side of a bridge circuit, thereby obtaining the signal to the pressure by means of an output of the bridge circuit.

Abstract: A pressure control valve arrangement includes a control slide valve body which is slidably accommodated in a central bore of a valve housing. The control slide valve body is acted upon at one of its axial sides by the controlled pressure, and at its other axial side by a tappet of a proportional electromagnet. The proportional magnet has a magnet housing which is rigidly connected to the valve housing. To provide a pressure control valve arrangement in which the accuracy of the pressure control is not influenced by disturbing factors, a pressure indicator is accommodated in the magnet housing; at least the pressure-responsive member of the pressure indicator is acted upon by the controlled pressure, which is supplied thereto through a connecting bore in the magnet housing and a part of the central bore of the valve housing in which the controlled pressure prevails.

Abstract: A control device and method of making the same are provided, the control device having a housing provided with an actuator chamber separated from a pressure differential chamber by a wall having an opening therethrough receiving an axially movable actuator pin that transmits axial movement of a movable part in the pressure differential chamber to the actuator chamber. A Hall effect transducer is disposed in the actuator chamber and the actuator pin has a magnet unit for operating the transducer as the movable part axially moves the actuator pin relative to the housing, the magnet unit being disposed in offset relation to the axis of the actuator pin and moving in unison therewith relative to the transducer.

Abstract: A pressure transducer employing a semiconductor diaphragm having a convoluted central section surrounded by a rigid peripheral section. The convolutions are a series of concentric grooves formed as squares producing a square nonplanar diaphragm in the preferred embodiment. The convolutions are formed on the semiconductor wafer by an anisotropic etch. Piezoresistive devices are diffused into the diaphragm in the peripheral region to form a bridge array. The transducer structure thus formed is capable of producing a linear and large magnitude voltage signal in response to a relatively small applied pressure or force.

Abstract: A transducer operating on the strain gauge principle having integral temperature compensation and calibration resistors is disclosed. In the presently preferred embodiment, a silicon dioxide layer is disposed on a silicon substrate. Platinum alloy strain gauge resistors are disposed on the silicon dioxide layer and form a Wheatstone bridge circuit configuration. Laser trimable chromium nitride, platinum alloy and gold temperature compensation and calibration resistors are formed on the silicon dioxide layer from the same films used to form the strain gauge, adhesion layers, conductors and bonding pads, to permit the transducer to be calibrated such that its electrical characteristics are in conformance to specified tolerances when the transducer is subjected to temperature variations.

Abstract: The housing has a flexible diaphragm secured over a fluid pressure inlet port in one end thereof, and a cover secured over an opening in the opposite end thereof. A plunger is mounted to reciprocate in the housing between said diaphragm and said cover in response to changes in fluid pressure at the inlet. Secured in the housing beneath the cover is a ceramic chip or substrate, which has a plane surface that extends normal to the axis of the plunger. A spirally shaped resistor element is printed or otherwise formed on the face of the chip, and a conically coiled compression spring is located in the housing between the resistor element and the plunger, and in such manner that its outer convolution at the larger end thereof is engaged with the outer convolution of the spirally shaped resistor element. The smaller end of the spring is connected to the plunger to be reciprocated thereby toward and away from the resistor element.

Abstract: This pressure sender or transducer comprises a metal housing having a steel cover and containing a rolling diaphragm which is secured over a cavity in the housing to communicate at one side with fluid under pressure, such as the oil in the crankcase of an automobile. Mounted centrally in the opposite side of the diaphragm is a rigid cup, which rotatably supports one end of a reciprocable plunger which in one embodiment carries two sets of equi-angularly spaced, resilient metal wipers or contacts, four of which are slidably engaged with the cylindrical operating surface of a printed resistor, which is mounted in the closed end of the cover, and four others of which are slidably engaged with the inner peripheral surface of the cover itself. The resistor comprises a steel can having a thin layer of porcelain baked on its outer peripheral surface, and a thin, cylindrical layer of resistance material printed and baked onto the porcelain layer with one end in electrical contact with the steel can.

Abstract: A pressure transducer is disclosed having a potentiometer including a resistor and relatively movable conductive wiper and a pressure sensor responsive to a variable pressure signal to move the wiper along the resistor so as to convert the variable pressure signal into a variable voltage signal. The resistor is mounted in conductive relationship in the potentiometer and so as to be slidably adjustable external to the transducer and relative to the wiper to thereby enable ready calibration of the voltage signal with respect to the pressure signal.

Abstract: A pressure unit assembly for providing an electrical signal representative of sensed pressure, for example an oil pressure unit assembly for an automobile engine. The unit is adapted for fabrication by automated equipment and it makes efficient use of constituent materials. Novel features of the unit include its spring contact element, its resistive element, and its electrical terminal configuration.