Monolithic accelerometer

Patent 5345824 Issued on September 13, 1994. Estimated Expiration Date:

March 4, 2013. Estimated Expiration Date is calculated based on simple USPTO term provisions. It does not account for terminal disclaimers, term adjustments, failure to pay maintenance fees, or other factors which might affect the term of a patent.

Abstract Claims Description Full Text

Patent References

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Inventors

Assignee

Analog Devices, Inc.

Application

No. 028922 filed on 03/04/1993

US Classes:

73/514.18, Electrostatic restoring means73/514.32Capacitive sensor

Examiners

Primary: Chapman, Jeanette E.

Attorney, Agent or Firm

Wolf, Greenfield & Sacks

Foreign Patent References

0198724 EP. 10/23/1986
299825 EP. 01/23/1989
0369352 EP. 05/23/1990

International Class

G01P 015/125

Abstract

An accelerometer comprising a microfabricated acceleration sensor and monolithically fabricated signal conditioning circuitry. The sensor comprises a differential capacitor arrangement formed by a pair of capacitors. Each capacitor has two electrodes, one of which it shares electrically in common with the other capacitor. One of the electrodes (e.g., the common electrode) is movable and one of the electrodes is stationary in response to applied acceleration. The electrodes are all formed of polysilicon members suspended above a silicon substrate. Each of the capacitors is formed of a plurality of pairs of electrode segments electrically connected in parallel and, in the case of the movable electrodes, mechanically connected to move in unison. When the substrate is accelerated, the movable electrodes move such that the capacitance of one of the capacitors increases, while that of the other capacitor decreases. The two capacitors are connected to signal conditioning circuitry which converts this differential capacitance into a corresponding voltage. Both open loop and force-balance operation are shown.

Other References

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