Texas Instruments Corporation

James L Tomlinson

Robert O Southworth

James P McAndrews

Gerald Floyd Davis

John R Fowler, Jr

A fluid pressure transducer assembly (,) includes an exemplary silicon or ceramic capacitive transducer (,) having a relatively flexible diaphragm portion (,) mounted on a ceramic substrate or circuit board (,) over a bore (,) so that the diaphragm is exposed to fluid pressure from a port (,) received through the bore. The circuit board is received in a plastic housing (,) laterally positioned by guides (,) on three height control pins (,) to vertically position the circuit board a defined, precise distance above a platform (,) on which a bead of adhesive sealing material has previously been placed, the sealing material having a height greater than the distance between a plane in which the free end of the height control pins lie and a plane in which the top surface of the platform lies. As a result, the circuit board is sealed to the plastic housing through a bead having a uniform, precise height all around its circumference to isolate temperature expansion stresses. According to another feature of the invention an electrically conductive layer (,) is formed on the top surface of the circuit board beneath the transducer (,) and another electrically conductive layer (,) is formed on the top surface of the transducer (,) electrically joined together to form an EMI shield.

Fluid pressure transducer apparatus and method for assembling

A pressure responsive variable capacitive transducer is shown in which a flat flexible diaphragm having a capacitor plate disposed thereon is mounted overlying a recess in a substrate having a capacitor plate disposed on the surface of the recess so that the plates are spaced apart a selected distance determined by the depth of the recess. In one embodiment a glass seal is located between the diaphragm and the substrate inwardly of the outer perimeter of the disphragm while in a second embodiment a glass seal is located outwardly from the outer perimeter of the diaphragm. The substrate is formed with bores adapted to receive electrical connection pins. Electrically conductive traces extend from electrically conductive layers to wells formed in the substrate contiguous with the bores to provide a gradual transition for the traces and an electrically conductive epoxy is infilled to electrically connect the pins to the traces.

Pressure transducer apparatus

A pressure responsive variable capacitive transducer is shown in which a flat flexible diaphragm having a capacitor plate disposed thereon is mounted overlying a recess in a substrate having a capacitor plate disposed on the surface of the recess so that the plates are spaced apart a selected distance determined by the depth of the recess. In one embodiment a glass seal is located between the diaphragm and the substrate inwardly of the outer perimeter of the diaphragm while in a second embodiment a glass seal is located outwardly from the outer perimeter of the diaphragm. The substrate is formed with bores adapted to receive electrical connection pins. Electrically conductive traces extend from electrically conductive layers to wells formed in the substrate contiguous with the bores to provide a gradual transition for the traces and an electrically conductive epoxy is infilled to electrically connect the pins to the traces.

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North Smithfield, RI, United States of America

James L Tomlinson