Texas Instruments Corporation

Steven Beringhause

Keith W Kawate

Larry K Johnson

Douglas B Strott

Eric P Reidemeister

Bryan J Dague

Raymond E Mandeville

Kai L Keasey

Mark D Mozgowiec

W Donald Rolph, Iii

Robert P Bishop

Stanley J Lukasiewicz

Edward M Gonsalves

Stephen B Offiler

Siegbert Hartauer

Alan G Amore

Andrew A Amatruda

Karl R Abrahamson

Vaclav F Vilimek

Robert Louis Bartosh

John M Armacost

Richard J Balcarek

Charles J Leedecke

A capacitive fluid pressure sensor (,) particularly adapted for use with fluids which are incompatible with conventional elastomeric fluid seals is shown in which a thin, relatively flexible metal diaphragm (,) is disposed over a fluid pressure receiving recess (16,, 16,) formed in a bottom wall of a hexport housing (,) and hermetically attached thereto. A capacitive sensor element (,) having a pressure sensitive surface (,) is disposed in the housing with the pressure sensitive surface placed against the metal diaphragm with a plastic intermediate layer (,) disposed between the metal diaphragm and the sensor element to minimize hysteresis and output error. The metal diaphragm and plastic layers are shown to be flat members in certain embodiments (,and,) and corrugated in another embodiment (,).

Hermetically sealed pressure sensing device

A fluid pressure responsive capacitive transducer (20) having a lowered manufacturing cost is shown in which a sheet (10) of cast or roll compacted tape material having a selected thickness is partitioned into a multitude of rectangular substrates portions (16) and another sheet (12) having another selected thickness is partitioned into a like number and sized diaphragm portions (18) and are processed in sheet form to apply capacitor plates and associated conductive traces as well as a sealing and spacing glass layer. At least one sheet is then separated into groups, generally comprising one, two or four portions, and pairs of groups of substrates and diaphragms are held together and heated to seal the transducers. Groups of more than one portion of the first and second sheets are then separated into individual transducers.

Pressure transducer apparatus and method for making

A fluid pressure sensor particularly useful for measuring pressure up to approximately 2000 psi has a hexport (12, 112, 212, 312) formed with a stop surface (26, 326) in a bottom wall (18) circumscribing a fluid pressure inlet (16). A pressure sensing module (22) is received on the stop surface and a distal end (40) of a wall (20, 120, 320) of the hexport is crimped to lock the pressure sensing module onto the stop surface with the stop surface limiting the amount of compression of an O-ring (30) disposed contiguous to and inboard of the stop surface. In one embodiment the crimp is placed directly on a metal ring (38) attached to a plastic connector (32) which in turn transfers the crimping force to the pressure sensing module. In other embodiments (FIGS. 2, 3) the crimp is placed directly in the pressure sensing module to form a subassembly. In one embodiment, a separate sleeve (142) member connects the subassembly to the plastic connector while in another embodiment the connector is provided with an extended skirt which snaps over the hexport to connect the connector to the subassembly. In yet another embodiment, the plastic connector (332) is formed with a strengthening flange (334) received around the pressure sensing module and the crimp is formed directly on the plastic connectors to reduce contact stresses in the crimp and compensate for crimp wall springback.

High pressure sensor apparatus with low cost compact packaging system

A housing member (100, 100', 100', 100'') used to interface with a coupling of a fluid pressure source and to house a pressure sensing assembly is shown having a metallic tubular sidewall with a cylindrical first portion (102), a non-cylindrical second portion (108, 108') and intermediate third portion (112, 112',112') with a plastic body member (114, 114', 114') disposed, as by insert molding, within the tubular sidewall. The plastic body member has a base wall portion (116) extending across the sidewall at the intermediate, third portion (112) and has an elongated portion (120, 120') with a threaded bore. The second portion of the sidewall extends along a longitudinal axis at least as far as the elongated portion of the plastic body member. In one embodiment a metallic insert (152) forms a continuation of the molded plastic thread and in another embodiment inwardly extending groove (160) of second portion (108') of the tubular sidewall reinforces the molded plastic thread. The housing member is adapted to receive a pressure sensing mechanism within the first portion (102) which portion is attached to a connector or the like by clamping the outer distal end (106) thereto.

Condition responsive electrical apparatus having improved low cost

An accelerometer device comprises a silicon semiconductor member having a mass mounted on a support by integral beams extending between the mass and support to permit movement of the mass in response to acceleration. Piezoresistive sensors are accommodated in the beams for sensing strain in the beams during movement of the mass to provide an output signal from the device corresponding to the acceleration. The beams each have an end secured to the support and an end secured to the mass and taper intermediate the beam ends to provide a high and substantially uniform strain throughout the tapered section of the beam. The piezoresistive sensor is accommodated in the tapered beam section to be responsive to that high, uniform strain. Preferably the member has four beams mounting the mass, each beam has a tapered section extending from each end of the beam toward the center of the beam, and each beam section has a piezoresistive sensor accommodated therein to be responsive to the uniform strain within that beam section. The piezoresistive sensors are conveniently interconnected to compensate for off-axis acceleration in one direction by compensation within each leg of a bridge circuit and to compensate for off-axis acceleration in another direction by compensation within the full bridge circuit.

Accelerometer with improved strain gauge sensing means

An accelerometer device particularly adapted for use in automotive safety air bag applications comprises an electrically insulating substrate having electrically conducting circuit paths, signal conditioning circuit components, and an accelerometer unit mounted thereon, the substrate being fixed in position on three pins within a housing. The accelerometer comprises a silicon mass movable in a silicon body relative to an integral silicon support to provide strain in the silicon body in response to acceleration and has piezoresistive sensors formed in the silicon body to be responsive to that strain to provide an electrical signal corresponding to the acceleration. A member having a selected configuration and thermal response characteristics suspends the accelerometer unit on the substrate with the piezoresistive sensors connected to the circuit paths with the piezoresistive sensors isolated from strain in the silicon body due to differences in thermal expansion between the silicon body, and the substrate during temperature changes likely to be encountered.

Accelerometer with strain isolated sensor

An accelerometer has a capacitor detect plate defined on an electrically insulating substrate adjacent a capacitor source plate connector and has circuit paths on the substrate connected to the detect plate and source plate connector. A resilient metal plate has an attachment portion secured to the source plate connector, has a capacitor source plate portion, has integral first beam elements extending away from the attachment portion and has a second beam element extending from the first beam elements back toward the attachment portion to dispose the capacitor source plate in spaced relation to the detect plate to form a capacitor having selected initial capacitance. The capacitor source plate member portion is movable relative to the detect plate to modify device capacitance in response to acceleration. Electronic components are mounted on the substrate connected to the circuit paths to provide an output signal corresponding to the acceleration. Preferably the device is cantilever mounted on a housing base with a part of the device substrate carrying the metal member extending over a housing recess to isolate that device end from thermal stresses in an accelerometer unit.

Capacitive accelerometer with cantilever mount

An accelerometer has a capacitor detect plate defined on an electrically insulating substrate adjacent a capacitor source plate connector and has circuit paths on the substrate connected to the detect plate and source plate connector. A resilient metal plate has an attachment portion secured to the source plate connector, has a capacitor source plate portion, has integral first beam elements extending away from the attachment portion and has a second beam element extending from the first beam elements back toward the attachment portion to dispose the capacitor source plate in spaced relation to the detect plate to form a capacitor having selected initial capacitance. The capacitor source plate member portion is movable relative to the detect plate to modify device capacitance in response to acceleration. Electronic components are mounted on the substrate connected to the circuit paths to provide an output signal corresponding to the acceleration. Preferably the device is mounted on a housing base with a part of the device substrate carrying the metal member extending over a housing recess to isolate that device end from thermal stresses in an accelerometer unit. Preferably the detect plate, source plate connector, resilient metal member, are provided on and soldered on a plurality of detachable sections of a ceramic insulating substrate in a batch process, and the substrate sections are then separated to form a plurality of accelerometer devices.

Capacitive accelerometer

Accelerometer

An accelerometer is shown with improved drop resistance for regulating automotive safety air-bag systems and the like. The device comprises a member of silicon semiconducting material having a central seismic mass mounted on a surrounding support by intervening beams, a pair of beams extending from each of four sides of the mass to the support and the mass being otherwise free of connection to the support to permit movement of the mass along an axis perpendicular to the plane of the support in highly sensitive response to acceleration forces along that axis. Each beam extends from a location near an end of one side of the mass so that the two beams extending from each side of the mass are widely spaced relative to each other to oppose rotational or twisting movement of the mass in response to off-axis acceleration forces to prevent damage to the beams during dropping of the accelerometer to the extent possible consistent with providing the desired sensitivity of response. Piezoresistive sensors are accommodated in selected beams to sense strain during movement of the mass to provide an output signal corresponding to acceleration force along the device axis. Stops limit movement of the mass along that axis to further avoid damage to the beams.

Accelerometer with central mass in support

A transducer arrangement comprising a magnetoresistive transducer including a magnetoresistive element responsive to magnetic flux passing therethrough in a predetermined direction to change its electrical resistance as a function of the intensity of the magnetic flux in the predetermined direction and a magnet to provide said magnetic flux. The transducer can include a permanent magnet having a planar surface with a magnetoresistive element offset from the axis of the magnet and optionally at an angle to the planar surface. The transducer can also include a concave surfaced magnet with the magnetoresistive element at an acute angle to the parallel flux lines emanating from the concave surface. As a further embodiment, the magnetoresistive element can be tilted on the magnet surface in two directions to provide a bias field and calibration. As a third embodiment, a high permeability pole piece can be positioned on the magnet surface between the magnet and the magnetoresistive element to minimize field variation due to nonuniformities in the magnet. There is also provided a module including an aluminum bracket mountable at the fore portion thereof and containing a magnetoresistive transducer circuit at the aft portion thereof, the circuit being coupled to a semiconductor circuit disposed at the center of the bracket. An epoxy resin encases the transducer circuit and semiconductor circuit as well as an optional cable or electrical connector at the fore portion of the bracket.

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N. Attleboro, MA, United States of America

Steven Beringhause