Monolithic silicon acceleration sensor
First Claim
1. A monolithic silicon acceleration sensor comprising at least one silicon acceleration sensor cell, the sensor cell comprising a movable silicon inertial mass with a first surface and an opposing second surface, the inertial mass positioned by beam members fixed to a silicon support structure, having a first and opposing second surface, the silicon sensor cell having means for detecting movement of the inertial mass in response to acceleration along two orthogonal axis of acceleration.
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Accused Products
Abstract
A monolithic silicon acceleration sensor capable of detecting acceleration along multiple orthogonal axes of acceleration is disclosed. The monolithic silicon acceleration sensor is micromachined from silicon to form one or more sensor cells, each sensor cell having an inertial mass positioned by beam members fixed to a silicon support structure. Movement of the inertial mass due to acceleration is detected by either a differential capacitance measurement between opposing surfaces of the inertial mass and electrically conductive layers on a top and a bottom cover plate structure, or by a resistance measurement of piezoresistive elements fixed to the positioning beam members. Embodiments of the invention are capable of detecting acceleration in a plane, along two orthogonal axes of acceleration, or along three orthogonal axis of acceleration.
13 Citations
30 Claims
- 1. A monolithic silicon acceleration sensor comprising at least one silicon acceleration sensor cell, the sensor cell comprising a movable silicon inertial mass with a first surface and an opposing second surface, the inertial mass positioned by beam members fixed to a silicon support structure, having a first and opposing second surface, the silicon sensor cell having means for detecting movement of the inertial mass in response to acceleration along two orthogonal axis of acceleration.
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9. The monolithic silicon acceleration sensor comprising:
an acceleration sensor cell for sensing acceleration along two orthogonal axes, the acceleration sensor cell comprising;
(a) an electrically conductive movable silicon inertial mass having a first surface and a second opposing surface, and positioned by electrically conductive beam members fixed to an electrically conductive silicon support structure having a first and a second surface;
(b) a first cover plate structure comprising a first electrically conductive layer spaced from the first surface of the inertial mass and formed on a first insulator fixed to the first surface of the silicon support structure, the first electrically conductive layer and the first surface of the inertial mass forming a first variable capacitor of a value depending on the position of the inertial mass;
(c) a second cover plate structure comprising a second electrically conductive layer spaced from the second surface of the inertial mass and formed on a second insulator fixed to the second surface of the silicon support structure, the second electrically conductive layer and the second surface of the inertial mass forming a second variable capacitor of a value depending on the position of the inertial mass; and
(d) a means for electrically connecting the inertial mass, the first metallic layer of the first cover plate structure, and the second metallic layer of the second cover plate structure to electronic circuitry capable of measuring the capacitance value of the first and second variable capacitor. - View Dependent Claims (10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
Specification