Capacitive in-plane accelerometer
First Claim
1. A micromechanical sensor comprising:
- a proof mass suspended over a substrate by a plurality of flexures; and
at least one stop mechanism disposed adjacent to a respective one of said plurality of flexures for preventing said flexure from deflecting more than a predetermined amount, said stop mechanism disposed such that said flexures communicate with said stop mechanism as a result of linear movement of said proof mass in a direction substantially perpendicular to said stop mechanism.
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Accused Products
Abstract
An accelerometer having one or more flexure stops for increasing the stiffness of the flexures when the accelerometer is subjected to relatively high acceleration. A wrap-around proof mass is suspended over a substrate by anchor posts and a plurality of flexures. In one embodiment, the proof mass has a rectangular frame including top and bottom beams extending between left and right beams and a central crossbeam extending between the left and right beams. Proof mass sense electrodes are cantilevered from the top, bottom and central beams and are interleaved with excitation electrodes extending from adjacent excitation electrode supports. Each of the flexure stops includes a pair of members extending along a portion of a respective flexure. Also described is a three axis accelerometer triad device and a dissolved wafer process for fabricating the devices described herein.
185 Citations
14 Claims
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1. A micromechanical sensor comprising:
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a proof mass suspended over a substrate by a plurality of flexures; and at least one stop mechanism disposed adjacent to a respective one of said plurality of flexures for preventing said flexure from deflecting more than a predetermined amount, said stop mechanism disposed such that said flexures communicate with said stop mechanism as a result of linear movement of said proof mass in a direction substantially perpendicular to said stop mechanism. - View Dependent Claims (2, 3, 4)
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5. A micromechanical sensor comprising:
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a substrate oriented in a first plane; a plurality of posts, each extending substantially vertically from said substrate to terminate at a corresponding plurality of support elements; a plurality of flexures, each having a first end coupled to a corresponding one of said support elements and a second end; a proof mass suspended over said substrate by said flexures and having an input axis in a second plane coplanar to said first plane, wherein said second end of each of said plurality of flexures is attached to said proof mass; and a stop extending from one of said support elements along a portion of one of said plurality of flexures, said stop disposed such that said flexures communicate with said stop mechanism as a result of linear movement of said proof mass along said input axis. - View Dependent Claims (6, 7, 8, 9, 10, 11, 12, 13, 14)
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Specification