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US 5,396,798 AGranted
Mechanical resonance, silicon accelerometer
AssigneeHoneywell Inc.
InventorRichard H. Frische
Life of this patent
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Abstract
A silicon accelerometer includes several silicon layers. The silicon layers form two silicon beams supported by flexure members. An acceleration responsive silicon mass is arranged to bend the flexure members in response to accelerations. The silicon beams are vibrated in vacuum chambers and gas damping is provided for the acceleration responsive mass and the flexure members. Sensing electronics detect vibration of the two silicon beams.
Claims32
An accelerometer comprising:
- first, second, third, and fourth silicon layers, each of the silicon layers having first and second surfaces;
- the second surface of the second silicon layer and the first surface of the third silicon layer being recessed to form first and second cavities and an acceleration responsive mass between the first and second cavities, the first and second cavities defining (a) first and second silicon flexure members in the first surface of the second silicon layer, respectively and (b) third and fourth silicon flexure members in the second surface of the third silicon layer respectively;
- the first silicon layer having first and second recesses in the second surface thereof, the first recess being arranged so that the first flexure member separates the first cavity and the first recess, and the second recess being arranged so that the second flexure member separates the second cavity and the second recess;
- the fourth silicon layer having third and fourth recesses in the first surface thereof, the third recess being arranged so that the third flexure member separates the first cavity and the third recess, and the fourth recess being arranged so that the fourth flexure member separates the second cavity and the fourth recess;
- first means, situated on the first flexure member, for sensing bending of the first flexure member;
- and,
- second means, situated on the fourth flexure member, for sensing bending of the fourth flexure member.
4 more elements
An accelerometer comprising:
- first, second, third, and fourth silicon layers, each of the silicon layers having first and second surfaces;
- the second surface of the second silicon layer and the first surface of the third silicon layer being recessed to form a first continuous cavity surrounding an acceleration responsive mass, the first continuous cavity forming a first flexure member in the first surface of the second silicon layer and a second flexure member in the second surface of the third silicon layer, the acceleration responsive mass being arranged to bend the first and second flexure members in response to acceleration;
- the first silicon layer having a second continuous cavity in the second surface thereof, the second continuous cavity being arranged so that the first flexure member separates the first and second continuous cavities;
- the fourth silicon layer having a third continuous cavity in the first surface thereof, the third continuous cavity being arranged so that the second flexure member separates the first and third continuous cavities;
- and,
- first and second sensing means for sensing bending of first and second beams respectively, the first and second sensing means mounted in the first and second flexure members, respectively, and being arranged with respect to one another for achieving common mode rejection;
- and wherein
- the first sensing means comprises a first silicon beam formed in the first flexure member and wherein the second sensing means comprises a second silicon beam formed in the second flexure member.
5 more elements
Dependencies are inferred from the claim text.