Resonant mechanical sensor
First Claim
1. A resonant mechanical sensor, comprising:
- a diaphragm substantially supported along the outer periphery thereof by a substrate, a boss member abutting a region of said diaphragm remote from said outer periphery, at least one resonator having one end integral with said diaphragm proximate to said region and another end integral with said diaphragm remote from said region, and means for detecting a change in the natural frequency of said resonator due to an applied load.
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Accused Products
Abstract
The sensor according to the present invention provides a device for measuring the magnitude of an applied load as a shift in resonant frequency of a mechanical resonator caused by load-induced strains on the resonator. The sensor includes a substrate, generally constructed of a semiconductor material, e.g. silicon, a diaphragm substantially supported along its outer periphery by the substrate, a boss abutting a region of the diaphragm remote from the outer periphery of the diaphragm, at least one resonator in the form of a beam having one end integral to the diaphragm proximate the region of the boss and the other end integral to the diaphragm remote from the boss, a hermetic seal for enclosing the resonator, and an exciter/detector for measuring changes in the natural frequency of the resonator due to an applied load. Preferably, the sensor includes a differential resonator configuration in which the resonators are positioned rectilinearly with respect to each other and are covered by the same hermetic seal.
99 Citations
15 Claims
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1. A resonant mechanical sensor, comprising:
a diaphragm substantially supported along the outer periphery thereof by a substrate, a boss member abutting a region of said diaphragm remote from said outer periphery, at least one resonator having one end integral with said diaphragm proximate to said region and another end integral with said diaphragm remote from said region, and means for detecting a change in the natural frequency of said resonator due to an applied load. - View Dependent Claims (2, 3, 5, 6, 7)
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4. A resonant mechanical sensor for detecting an applied load, comprising:
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a substrate; a diaphragm substantially supported along the outer periphery thereof by said substrate; a boss member abutting a region of said diaphragm remote from said outer periphery; at least one resonator having one end integral with said diaphragm proximate to said region and another end integral with said diaphragm remote from said region; means for hermetically sealing and enclosing said resonator; and means for detecting a change in the natural frequency of said resonator due to an applied load.
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8. A resonant mechanical sensor for detecting an applied mechanical load, comprising:
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a substrate; a diaphragm substantially supported along the outer periphery thereof by said substrate; a boss member abutting a region of said diaphragm remote from said outer periphery; at least one resonator in the form of a beam having one end integral with said diaphragm proximate to said region and another end integral with said diaphragm remote from said region; a first electrode disposed on said beam; a piezoelectric layer encapsulated by an insulator disposed on said first electrode; a second electrode disposed on said piezoelectric layer; and a hermetic cap enclosing said beam. - View Dependent Claims (9)
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10. A method for fabricating a resonant mechanical sensor, comprising the steps of:
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forming a diaphragm substantially supported along its outer periphery by a substrate; providing a boss abutting a region of said diaphragm substantially remote from said outer periphery; and forming a resonator having one end integral to said diaphragm proximate to said region and another end integral to said diaphragm remote from said region. - View Dependent Claims (11, 12, 13, 14, 15)
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Specification