Miniaturized piezoelectric accelerometers
First Claim
1. A miniaturized piezoelectric accelerometer comprising:
- a support frame having a cavity therein, the cavity having a central longitudinal axis,a seismic mass in the cavity and having a central longitudinal axis, the central longitudinal axis of the cavity and the central longitudinal axis of the seismic mass being co-incident,a plurality of suspension beams extending from the support frame to the seismic mass, each of the suspension beams having a piezoelectric thin film coated on a top surface thereof,a pair of inter-digital electrodes deposited on an upper surface of each piezoelectric thin film, andat least one terminal of each of the inter-digital electrodes being routed to and electrically connected at a top surface of the seismic mass.
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Accused Products
Abstract
The miniaturized piezoelectric accelerometer includes a support frame (102) having a cavity (104) and a seismic mass (108) supported by a plurality of suspension beams (110) extending from the support frame (102). Each of the suspension beams (110) has a piezoelectric thin film coated on a top surface thereof, with a pair of inter-digital electrodes (114) deposited on an upper surface of each piezoelectric thin film. The presence of acceleration excites bending and thus strain in the piezoelectric thin film, which in turn causes electrical signals to be generated over terminals of the electrodes (114). To collect constructively the output of the electrodes (114), one terminal of each of the electrodes (114) is routed to and electrically connected at a top surface (308) of the seismic mass (108).
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Citations
20 Claims
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1. A miniaturized piezoelectric accelerometer comprising:
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a support frame having a cavity therein, the cavity having a central longitudinal axis, a seismic mass in the cavity and having a central longitudinal axis, the central longitudinal axis of the cavity and the central longitudinal axis of the seismic mass being co-incident, a plurality of suspension beams extending from the support frame to the seismic mass, each of the suspension beams having a piezoelectric thin film coated on a top surface thereof, a pair of inter-digital electrodes deposited on an upper surface of each piezoelectric thin film, and at least one terminal of each of the inter-digital electrodes being routed to and electrically connected at a top surface of the seismic mass. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A method of fabricating miniaturized piezoelectric accelerometers comprising:
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depositing a piezoelectric thin film and an electrode layer on a front side of a wafer, patterning the electrode layer to produce inter-digital electrodes and electrical connections for the inter-digital electrodes, with at least one terminal of the inter-digital electrodes being routed to and electrically connected at a top surface of a part of the wafer that defines or that will define a seismic mass of the accelerometer, etching the piezoelectric thin film and the wafer from the front side to form a plurality of suspension beams extending from a support frame of the accelerometer, and etching from a back side of the wafer to form a cavity of the support frame and the seismic mass. - View Dependent Claims (17, 18, 19, 20)
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Specification