CAPACITIVE STRAIN SENSOR
First Claim
1. A capacitive strain sensor comprising a differential capacitor comprising:
- a first strain sensing element;
a second strain sensing element; and
a bending beam, wherein the bending beam is positioned between the first strain sensing element and the second strain sensing element, and wherein the sensor is configured to enhance the effect of strain in a substrate along a sensing axis and attenuate the effect of strain in the substrate along a cross-axis transverse to the sensing axis.
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Accused Products
Abstract
Provided are capacitive strain sensors. In certain embodiments, the capacitive strain sensor can continuously and accurately measure strain in corrosive ambient conditions and may operate up to 370° C. or more in air. The sensor includes a differential capacitor that includes a bending beam structure. In some instances, the sensor is configured to increase the effect of strain in a substrate along a sensing axis while attenuating the effect of cross-axis strain. Also provided are methods of making the capacitive strain sensors, e.g., using Micro-Electro-Mechanical System (MEMS) fabrication techniques, and methods of using the capacitive strain sensors.
17 Citations
21 Claims
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1. A capacitive strain sensor comprising a differential capacitor comprising:
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a first strain sensing element; a second strain sensing element; and a bending beam, wherein the bending beam is positioned between the first strain sensing element and the second strain sensing element, and wherein the sensor is configured to enhance the effect of strain in a substrate along a sensing axis and attenuate the effect of strain in the substrate along a cross-axis transverse to the sensing axis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method for detecting strain in a substrate comprising:
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detecting a change in capacitance of a capacitive strain sensor on a substrate, wherein the capacitive strain sensor comprises a differential capacitor comprising; a first strain sensing element; a second strain sensing element; and a bending beam positioned between the first strain sensing element and the second strain sensing element such that strain in the substrate deforms the bending beam causing the change in capacitance; and determining a value corresponding to the strain in the substrate based on the change in capacitance.
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18. A method for detecting strain in a substrate comprising:
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attaching a capacitive strain sensor to a substrate, wherein the capacitive strain sensor comprises a differential capacitor comprising; a first strain sensing element; a second strain sensing element; and a bending beam positioned between the first strain sensing element and the second strain sensing element, such that strain in the substrate deforms the bending beam; detecting a change in capacitance of the differential capacitor caused by deformation of the bending beam; and determining a value corresponding to the strain in the substrate based on the change in capacitance.
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19. A method of making a capacitive strain sensor comprising:
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etching a silicon on insulator (SOI) wafer in the pattern of a capacitive strain sensor, wherein the capacitive strain sensor comprises a differential capacitor comprising; a first strain sensing element; a second strain sensing element; and a bending beam positioned between the first strain sensing element and the second strain sensing element; and releasing the capacitive strain sensor from the wafer. - View Dependent Claims (20)
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21-35. -35. (canceled)
Specification