Capacitive pressure sensor
First Claim
Patent Images
1. A pressure sensor, comprising:
- a first conductive layer including first and second conductive plates;
a second conductive layer; and
a compressible dielectric layer between the first and second conductive layers, wherein one side of the compressible dielectric layer has contiguous contact with both a surface of the first conductive plate and a surface of the second conductive plate, and wherein an opposite side of the compressible dielectric layer has contiguous contact with a surface of the second conductive layer;
wherein the first conductive plate and the second conductive layer form a first capacitor;
wherein the second conductive plate and the second conductive layer form a second capacitor in series with the first capacitor;
wherein the capacitances of the first and second capacitors are measurable via a first lead coupled to the first conductive plate and a second lead coupled to the second conductive plate without a lead coupled to the second conductive layer; and
wherein the first and second capacitors are configured to reflect a capacitance according to pressure changes on the compressible dielectric layer.
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Abstract
A capacitive pressure sensor comprises a pair of conductive plates surrounding a compressible dielectric to form a capacitor. Changes in pressure create changes in the capacitance of the capacitor which in turn may be measured to determine the changes in pressure. The pressure sensor may be constructed to be temperature and centripetal force compensated so that it may be positioned in a tire. A further embodiment uses the conductive plates to form a radiating element for the sensor such that it may wirelessly communicate with a remote interrogator.
35 Citations
54 Claims
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1. A pressure sensor, comprising:
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a first conductive layer including first and second conductive plates; a second conductive layer; and a compressible dielectric layer between the first and second conductive layers, wherein one side of the compressible dielectric layer has contiguous contact with both a surface of the first conductive plate and a surface of the second conductive plate, and wherein an opposite side of the compressible dielectric layer has contiguous contact with a surface of the second conductive layer; wherein the first conductive plate and the second conductive layer form a first capacitor; wherein the second conductive plate and the second conductive layer form a second capacitor in series with the first capacitor; wherein the capacitances of the first and second capacitors are measurable via a first lead coupled to the first conductive plate and a second lead coupled to the second conductive plate without a lead coupled to the second conductive layer; and wherein the first and second capacitors are configured to reflect a capacitance according to pressure changes on the compressible dielectric layer. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. A method of sensing pressure changes in a wheel, the method comprising:
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detecting signals from a pressure sensor in the wheel, wherein the pressure sensor includes; a first conductive layer mounted on a substrate and having a top surface opposite the substrate; a second conductive layer mounted on the substrate and having a top surface opposite the substrate, wherein the second conductive layer is arranged substantially co-planar to the first conductive layer and forms an interdigital structure with the first conductive layer; and a compressible dielectric layer making contiguous contact with both the top surface of the first conductive layer and the top surface of the second conductive layer, wherein the first conductive layer, the second conductive layer, and the compressible dielectric layer form a capacitor; wherein the capacitor is configured to reflect a capacitance according to pressure changes on the compressible dielectric layer, and wherein the signals comprise pressure information corresponding to the capacitance; and determining pressure changes in the wheel based on the signals from the pressure sensor. - View Dependent Claims (22, 23, 24, 25, 26, 27, 28)
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29. A method of sensing pressure changes in a tire on a vehicle, the method comprising:
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associating a remote communication device with a pressure sensor placed in a tire, wherein the pressure sensor includes; a first conductive layer including first and second conductive plates; a second conductive layer; and a compressible dielectric layer between the first and second conductive layers, wherein one side of the compressible dielectric layer has contiguous contact with both a surface of the first conductive plate and a surface of the second conductive plate, and wherein an opposite side of the compressible dielectric layer has contiguous contact with a surface of the second conductive layer; wherein the first conductive plate and the second conductive layer form a first capacitor; wherein the second conductive plate and the second conductive layer form a second capacitor in series with the first capacitor; and wherein the first and second capacitors are configured to reflect a capacitance in relation to pressure changes on the compressible dielectric layer; determining the capacitance of the first and second capacitors via a first lead coupled to the first conductive plate and a second lead coupled to the second conductive plate without an electrical lead coupled to the second conductive layer; determining pressure changes in the tire based on changes in the compressible dielectric layer reflected in the capacitances of the first and second capacitors; and transmitting information about the pressure changes in the tire via the remote communication device to a vehicle control system. - View Dependent Claims (30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47)
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48. A pressure sensor, comprising:
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a first conductive layer mounted on a substrate and having a top surface opposite the substrate; a second conductive layer mounted on the substrate and having a top surface opposite the substrate, wherein the second conductive layer is arranged substantially co-planar to the first conductive layer and forms an interdigital structure with the first conductive layer; and a compressible dielectric layer making contiguous contact with both the top surface of the first conductive layer and the top surface of the second conductive layer, wherein the first conductive layer, the second conductive layer, and the compressible dielectric layer form a capacitor; wherein the capacitor is configured to reflect a capacitance according to pressure changes on the compressible dielectric layer. - View Dependent Claims (49, 50, 51, 52, 53, 54)
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Specification