Acceleration sensor
First Claim
1. An acceleration sensor comprising:
- a substrate;
an anchor portion formed on the substrate;
a support beam having one end connected to the anchor portion and extending spaced apart from the substrate;
a proof mass being connected to the other end of the support beam and spaced apart from the substrate;
first and second piezoelectric bending resonators, each having one end connected to the anchor portion and the other end connected to the proof mass or the support beam thereby extending to both sides of the support beam, and each comprising a first electrode, a first piezoelectric film and a second electrode being stacked in a direction perpendicular to the first piezoelectric film to perform bending resonance motion in the direction;
a first comparison unit configured to output a first value, the first value is a difference of a resonance frequency between the first and second piezoelectric bending resonators; and
a first calculation unit configured to calculate an acceleration in a direction perpendicular to an extending direction of the support beam from the first value.
1 Assignment
0 Petitions
Accused Products
Abstract
The present embodiments provide an acceleration sensor, which enables highly accurate detection and has an extremely compact size. The acceleration sensor of the present embodiments is provided with a substrate, a anchor portion formed on the substrate, a support beam, which has one end connected to the anchor portion and extends across a space from the substrate, and a proof mass which is connected to the other end of the support beam and held across a space from the substrate. The acceleration sensor is further provided with first and second piezoelectric bending resonators, a comparison unit, and a calculation unit. The first and second piezoelectric bending resonators have one end connected to the anchor portion and the other end connected to the proof mass or the support beam and have a stack of a first electrode, a first piezoelectric film, and a second electrode. The first and second piezoelectric bending resonators extend on the both sides of the support beam and perform bending resonance motion in a direction perpendicular to the piezoelectric film. The comparison unit measures a difference of a resonance frequency between the first and second piezoelectric bending resonators. The calculation unit calculates an acceleration in a direction perpendicular to the extending direction of the support beam in the substrate surface from the difference of the resonance frequency.
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Citations
10 Claims
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1. An acceleration sensor comprising:
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a substrate; an anchor portion formed on the substrate; a support beam having one end connected to the anchor portion and extending spaced apart from the substrate; a proof mass being connected to the other end of the support beam and spaced apart from the substrate; first and second piezoelectric bending resonators, each having one end connected to the anchor portion and the other end connected to the proof mass or the support beam thereby extending to both sides of the support beam, and each comprising a first electrode, a first piezoelectric film and a second electrode being stacked in a direction perpendicular to the first piezoelectric film to perform bending resonance motion in the direction; a first comparison unit configured to output a first value, the first value is a difference of a resonance frequency between the first and second piezoelectric bending resonators; and a first calculation unit configured to calculate an acceleration in a direction perpendicular to an extending direction of the support beam from the first value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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Specification