GRA MEMS accelerometer
First Claim
1. An accelerometer that lies generally in a plane, for detecting acceleration along an input axis that is orthogonal to the plane of the accelerometer, comprising:
- a substrate defining a surface;
spaced bonding pads coupled to the substrate and projecting from the surface of the substrate;
a generally planar plate Servo Member (SM) spaced from and essentially parallel to the surface of the substrate and flexibly coupled to the bonding pads by servo member flexures such that the SM is capable of oscillatory motion about a servo axis that is orthogonal to the plane of the SM;
a generally planar plate Torque Summing Member (TSM) located within, coplanar with, and flexibly coupled to the SM such that the TSM is capable of rotational motion relative to the substrate about an output axis that is in the plane of the TSM and orthogonal to the servo axis, the TSM being mass-imbalanced relative to the output axis by a geometric asymmetry about the output axis;
a generally planar plate rotor located within, coplanar with, and flexibly coupled to the TSM such that the rotor is capable of rotary oscillatory motion relative to the TSM about a rotor axis that is in the plane of the rotor, the TSM and the SM;
one or more rotor drives for directly oscillating the rotor about the rotor axis at a rotor oscillation frequency and amplitude;
one or more SM drives for oscillating the SM about the servo axis at a servo member oscillation frequency and amplitude, and thereby also oscillating the rotor and the TSM about the servo axis at the servo member oscillation frequency;
one or more rotor motion sensors that detect oscillation of the rotor relative to the substrate about the rotor axis;
one or more SM motion sensors that detect oscillation of the SM about the servo axis; and
one or more TSM motion sensors that detect rotation of the TSM relative to the substrate about the output axis.
2 Assignments
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Accused Products
Abstract
A planar MEMS accelerometer that detects acceleration along an input axis that is orthogonal to the plane. There are spaced bonding pads coupled to a substrate. A generally planar Servo Member (SM) is flexibly coupled to the bonding pads by servo member flexures such that the SM is capable of oscillatory motion about a servo axis that is orthogonal to the plane. A generally planar plate Torque Summing Member (TSM) is located within, coplanar with, and flexibly coupled to the SM such that the TSM is capable of rotational motion about an output axis that is in the plane and orthogonal to the servo axis. The TSM is mass-imbalanced relative to the output axis. A generally planar plate rotor is located within, coplanar with, and flexibly coupled to the TSM such that it is capable of rotary oscillatory motion relative to the TSM about a rotor axis that is in the plane. Rotor drives directly oscillate the rotor about the rotor axis at a rotor oscillation frequency and amplitude. SM drives oscillate the SM about the servo axis at a SM oscillation frequency and amplitude, and thereby also oscillate the rotor and TSM about the servo axis at the SM oscillation frequency. Motion sensors detect oscillation of the rotor and the SM. TSM motion sensors detect rotation of the TSM relative to the substrate about the output axis.
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Citations
42 Claims
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1. An accelerometer that lies generally in a plane, for detecting acceleration along an input axis that is orthogonal to the plane of the accelerometer, comprising:
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a substrate defining a surface; spaced bonding pads coupled to the substrate and projecting from the surface of the substrate; a generally planar plate Servo Member (SM) spaced from and essentially parallel to the surface of the substrate and flexibly coupled to the bonding pads by servo member flexures such that the SM is capable of oscillatory motion about a servo axis that is orthogonal to the plane of the SM; a generally planar plate Torque Summing Member (TSM) located within, coplanar with, and flexibly coupled to the SM such that the TSM is capable of rotational motion relative to the substrate about an output axis that is in the plane of the TSM and orthogonal to the servo axis, the TSM being mass-imbalanced relative to the output axis by a geometric asymmetry about the output axis; a generally planar plate rotor located within, coplanar with, and flexibly coupled to the TSM such that the rotor is capable of rotary oscillatory motion relative to the TSM about a rotor axis that is in the plane of the rotor, the TSM and the SM; one or more rotor drives for directly oscillating the rotor about the rotor axis at a rotor oscillation frequency and amplitude; one or more SM drives for oscillating the SM about the servo axis at a servo member oscillation frequency and amplitude, and thereby also oscillating the rotor and the TSM about the servo axis at the servo member oscillation frequency; one or more rotor motion sensors that detect oscillation of the rotor relative to the substrate about the rotor axis; one or more SM motion sensors that detect oscillation of the SM about the servo axis; and one or more TSM motion sensors that detect rotation of the TSM relative to the substrate about the output axis. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42)
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Specification