Pressure sensor with conductive ceramic membrane
First Claim
1. A capacitative pressure sensor for sensing a fluid pressure, the capacitative pressure sensor comprising:
- a chamber partially defined by a flexible membrane that is at least partially formed from a conductive ceramic material, the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects due to pressure differentials between the reference pressure and the fluid pressure;
a conductive layer deposited in the chamber to form a first capacitor electrode spaced from the flexible membrane forming a second capacitor electrode; and
,associated circuitry comprising CMOS layers deposited between the conductive layer and an underlying supporting substrate;
wherein,the associated circuitry is configured to convert the deflection of the flexible membrane into an output signal indicative of the fluid pressure.
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Accused Products
Abstract
A pressure sensor (30) for sensing a fluid pressure in harsh environments such as the air pressure in a tire, by using a chamber (58) partially defined by a flexible membrane (50), the chamber (58) containing a fluid at a reference pressure, such that the flexible membrane (50) deflects due to pressure differentials between the reference pressure and the fluid pressure; and,
- associated circuitry (34) for converting the deflection of the flexible membrane (50) into an output signal indicative of the fluid pressure; wherein,
- the membrane (50) is at least partially formed from a metal ceramic material.
Metal ceramics can be deposited as a thin membrane with sufficient flexibility for sensing pressure while providing corrosion and wear resistance. Furthermore, these materials are generally well suited to micro fabrication processes and electrically conductive so they can be used in capacitative and resistive type pressure sensors.
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Citations
41 Claims
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1. A capacitative pressure sensor for sensing a fluid pressure, the capacitative pressure sensor comprising:
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a chamber partially defined by a flexible membrane that is at least partially formed from a conductive ceramic material, the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects due to pressure differentials between the reference pressure and the fluid pressure; a conductive layer deposited in the chamber to form a first capacitor electrode spaced from the flexible membrane forming a second capacitor electrode; and
,associated circuitry comprising CMOS layers deposited between the conductive layer and an underlying supporting substrate;
wherein,the associated circuitry is configured to convert the deflection of the flexible membrane into an output signal indicative of the fluid pressure. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41)
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Specification