Micro-electromechanical pressure sensor
First Claim
1. A pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
- a chamber partially defined by a flexible membrane, the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects from any pressure difference between the reference pressure and the fluid pressure, the membrane being at least partially formed from conductive material;
associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure; and
a second chamber with a second membrane the second chamber being sealed from the fluid pressure and the second membrane from predetermined pressure difference in the second chamber;
wherein,the associated circuitry converts the deflection of the second membrane into an adjustment of the output signal to compensate for the temperature of the sensor.
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0 Petitions
Accused Products
Abstract
A pressure sensor (30) for harsh environments such as vehicle tires, the sensor having a chamber (58) partially defined by a flexible membrane (50), the chamber (58) containing a fluid at a reference pressure. In use, the flexible membrane (50) deflects due to pressure differentials between the reference pressure and the fluid pressure, so that, associated circuitry (34) can convert the deflection of the flexible membrane into an output signal indicative of the fluid pressure. The sensor is a MEMS device whereby the recess, the flexible membrane and the associated circuitry are formed using lithographically masked etching and deposition techniques. MEMS fabrication techniques can produce the sensor in such high volumes that the unit cost of each sensor is very low. The MEMS sensor is so small that it can be installed in very restricted areas such as the stem of the tire valve.
26 Citations
39 Claims
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1. A pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
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a chamber partially defined by a flexible membrane, the chamber containing a fluid at a reference pressure, such that the flexible membrane deflects from any pressure difference between the reference pressure and the fluid pressure, the membrane being at least partially formed from conductive material; associated circuitry for converting the deflection of the flexible membrane into an output signal indicative of the fluid pressure; and a second chamber with a second membrane the second chamber being sealed from the fluid pressure and the second membrane from predetermined pressure difference in the second chamber;
wherein,the associated circuitry converts the deflection of the second membrane into an adjustment of the output signal to compensate for the temperature of the sensor. - 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)
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Specification