Capacitive sensor
First Claim
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1. A capacitive sensor element for differential pressure sensors, comprising:
- a first fixed charge plate with a port coupled to a first pressure source;
a flexible charge plate;
means for securely separating the first fixed charge plate and the flexible charge plate wherein the charge plates are an initial distance apart;
means for electrically grounding the flexible charge plate;
a lid with a port coupled to a second pressure source;
means for securely separating the flexible charge plate and the lid;
means for providing a voltage to the first fixed charge plate;
means for measuring an accumulated voltage across the first fixed charge plate and the flexible charge plate for a given amount of time wherein the accumulated voltage is a function of a variable distance between the first charge plate and the flexible charge plate; and
means for calculating the differential pressure based on the change in the initial distance and the variable distance.
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Abstract
A capacitive sensor for measuring pressure comprises a fixed charge plate integral to a printed circuit board, a flexible charge plate that is grounded, a conductive donut-shaped adhesive spacer between the charge plates, a lid, a non-conductive donut-shaped adhesive spacer between the second charge plate and the lid, means of providing a pressure, fixed or variable, to both sides of the flexible charge plate, wherein a microcontroller controls a power supply and provides a voltage to the first charge plate wherein the accumulative voltage may be measured as a means of determining differential pressure.
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Citations
26 Claims
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1. A capacitive sensor element for differential pressure sensors, comprising:
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a first fixed charge plate with a port coupled to a first pressure source; a flexible charge plate; means for securely separating the first fixed charge plate and the flexible charge plate wherein the charge plates are an initial distance apart; means for electrically grounding the flexible charge plate; a lid with a port coupled to a second pressure source; means for securely separating the flexible charge plate and the lid; means for providing a voltage to the first fixed charge plate; means for measuring an accumulated voltage across the first fixed charge plate and the flexible charge plate for a given amount of time wherein the accumulated voltage is a function of a variable distance between the first charge plate and the flexible charge plate; and means for calculating the differential pressure based on the change in the initial distance and the variable distance. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A capacitive sensor element for absolute pressure sensors, comprising:
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a fixed charge plate with a port coupled to a pressure source; a flexible charge plate; means for securely separating the fixed charge plate and the flexible charge plate wherein the charge plates are an initial distance apart; means for electrically grounding the flexible charge plate; a lid; means for securely separating the flexible charge plate and the lid; means for providing a voltage to the fixed charge plate; means for measuring an accumulated voltage across the fixed charge plate and the flexible charge plate for a given amount of time wherein the accumulated voltage is a function of a variable distance between the first charge plate and the flexible charge plate; and means for calculating the pressure source. - View Dependent Claims (18, 19, 20, 21)
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22. A method of producing a capacitive pressure sensor assembly, comprising the steps of:
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(1) producing a fixed charge plate and a flexible charge plate; (2) securing and separating the fixed charge plate and the flexible charge plate a first distance apart; (3) providing means to ground the flexible charge plate; (4) producing a lid; (5) securing and separating the flexible charge plate and the lid; (6) providing means to apply a first pressure to one side of the flexible charge plate and means to apply a second pressure to the other side of the flexible charge plate; (6) providing means to apply a voltage to the fixed plate; (7) providing means to measure an accumulated voltage across the fixed charge plate and the flexible charge plate for a given amount of time wherein the accumulated voltage is a function of a variable distance between the fixed charge plate and the flexible charge plate; and (8) providing means to calculate a differential between the first pressure and the second pressure. - View Dependent Claims (23, 24, 25, 26)
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Specification