Capacitative pressure sensor for oxidative environments
First Claim
1. A capacitative pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
- a pair of spaced electrodes forming a capacitor, one of the electrodes being a membrane extending between fluid at a reference pressure and the fluid pressure to be sensed such that the membrane deflects due to pressure differentials between the reference pressure and the fluid pressure, the membrane is a conductive laminate having at least one of its layers formed from the deposition of a transition metal nitride; and
, associated circuitry for converting the deflection of the membrane into an output signal indicative of the fluid pressure.
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Accused Products
Abstract
A capacitative pressure sensor (30) for harsh environments such as vehicle tires. The sensor has two opposing electrodes (36 and 50). One electrode is a membrane (50) that extends between fluid at a reference pressure and fluid at the pressure to be sensed. In use, the flexible membrane (50) deflects due to pressure differentials between the reference pressure and the fluid pressure. Associated circuitry converts the deflection into a signal indicative of the pressure to be sensed. The membrane is a laminate at least partially formed from a transition metal nitride because transition metal nitrides are a metal ceramics with high yield strength and metallic bonding that makes it suitable for use in extreme environments. They can also readily include an oxidizing component such as aluminium so that the membrane form a passivating surface oxide layer to protect it from oxidative failure.
23 Citations
19 Claims
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1. A capacitative pressure sensor for sensing a fluid pressure, the pressure sensor comprising:
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a pair of spaced electrodes forming a capacitor, one of the electrodes being a membrane extending between fluid at a reference pressure and the fluid pressure to be sensed such that the membrane deflects due to pressure differentials between the reference pressure and the fluid pressure, the membrane is a conductive laminate having at least one of its layers formed from the deposition of a transition metal nitride; and
,associated circuitry for converting the deflection of the 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)
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Specification