Vertically integrated 3-axis MEMS accelerometer with electronics
First Claim
1. An accelerometer comprising:
- an actuator substrate;
a reference substrate; and
at least two proof masses substantially on the actuator substrate, and suspended over the reference substrate, wherein the at least two proof masses are not electrically or mechanically coupled to each other, the at least two proof masses substantially constrained to move only along the same axis;
the at least two proof masses having at least one stationary electrode to form a capacitance which changes with the acceleration induced in one direction.
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Abstract
A system and method in accordance with the present invention provides for a low cost, bulk micromachined accelerometer integrated with electronics. The accelerometer can also be integrated with rate sensors that operate in a vacuum environment. The quality factor of the resonances is suppressed by adding dampers. Acceleration sensing in each axis is achieved by separate structures where the motion of the proof mass affects the value of sense capacitors differentially. Two structures are used per axis to enable full bridge measurements to further reduce the mechanical noise, immunity to power supply changes and cross axis coupling. To reduce the sensitivity to packaging and temperature changes, each mechanical structure is anchored to a single anchor pillar bonded to the top cover.
246 Citations
22 Claims
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1. An accelerometer comprising:
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an actuator substrate; a reference substrate; and at least two proof masses substantially on the actuator substrate, and suspended over the reference substrate, wherein the at least two proof masses are not electrically or mechanically coupled to each other, the at least two proof masses substantially constrained to move only along the same axis;
the at least two proof masses having at least one stationary electrode to form a capacitance which changes with the acceleration induced in one direction. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20)
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21. An accelerometer comprising:
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an actuator substrate; a reference substrate; and at least two proof-masses, each of the at least two proof masses, substantially on the actuator substrate and bonded to the reference substrate at an anchor, with at least one flexure spring, suspended over the reference substrate, wherein the at least two proof masses are not electrically or mechanically coupled to each other;
the at least two proof masses substantially constrained to move only along the same axis;
each of the at least two proof masses having at least one stationary electrode to form a capacitance which changes with the acceleration induced in one direction;wherein the at least two proof masses are connected electrically to the reference substrate at an anchor; wherein the reference substrate comprises a CMOS integrated circuit. - View Dependent Claims (22)
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Specification