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US 4,726,232 AGranted
Temperature coefficient compensated pressure transducer
AssigneeGould Inc.
InventorDonald J. Koneval
Life of this patent
Estimating the term…
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.
Claims9
An integrated circuit pressure transducer comprising:
- a diaphragm, said diaphragm being formed of a material having a first thermal expansion coefficient;
- measuring means for measuring the displacement of said diaphragm in response to an applied pressure including four piezoresistive resistors disposed on said diaphragm and connected as the elements of a Wheatstone Bridge circuit, said resistors being positioned on each near the edges of said diaphragm;
- an insulation layer covering said diaphragm and insulating said diaphragm from the circuit connections of said measuring means, said insulation layer being formed of a second material having a second thermal expansion coefficient;
- and
- a compensation layer on said insulation layer, said compensation layer including a body of material having a third expansion coefficient and being of a volumetric dimension selected to produce a predetermined value of temperature compensation in said transducer, the peripheral edges of said body being displaced laterally inwardly from said resistors.
2 more elements
Dependencies are inferred from the claim text.