MEMS ACCELEROMETER HAVING A FLUX CONCENTRATOR BETWEEN PARALLEL MAGNETS
First Claim
1. A microelectromechanical (MEMS) accelerometer comprising:
- a housing;
a proof mass suspended within the housing by at least one torsional flexure;
a coil on the proof mass;
a first magnet positioned near a first side of the proof mass;
at least one pole piece located outside the coil; and
at least one magnetic flux concentrator located inside the coil opposite at least one of the at least one pole pieces.
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Accused Products
Abstract
Microelectromechanical (MEMS) accelerometer and acceleration sensing methods. An example MEMS accelerometer includes a housing, a proof mass suspended within the housing by at least one torsional flexure, at least one planar coil on the proof mass that extends on both sides of an axis of rotation of the proof mass, at least one magnet oriented such that a north-south axis of the at least one magnet is oriented approximately orthogonal to the rotational axis of the proof mass, at least one pole piece located outside the coil, and at least one magnetic flux concentrator located inside the coil opposite the at least one of the at least one pole pieces. A method includes sensing a change in capacitance of a pickoff in the MEMS accelerometer and rebalancing the MEMS accelerometer by sending a current through the planar coil between the magnetic flux concentrator and the pole piece.
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Citations
17 Claims
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1. A microelectromechanical (MEMS) accelerometer comprising:
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a housing; a proof mass suspended within the housing by at least one torsional flexure; a coil on the proof mass; a first magnet positioned near a first side of the proof mass; at least one pole piece located outside the coil; and at least one magnetic flux concentrator located inside the coil opposite at least one of the at least one pole pieces. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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17. A method of sensing acceleration with a MEMS accelerometer that includes a proof mass having an axis of rotation about at least one flexure, a coil on the proof mass positioned such that the coil extends on both sides of the axis of rotation, at least one magnet, at least one pole piece, and at least one magnetic flux concentrator, the at least one magnet, pole piece, and magnetic flux concentrator positioned such that a magnetic flux field flows approximately orthogonally to the axis of rotation across the coil between the pole piece and the magnetic flux concentrator, the method comprising:
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sensing a change in capacitance of a pickoff in the MEMS accelerometer; and rebalancing the MEMS accelerometer by sending a current through the coil between the pole piece and the magnetic flux concentrator.
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Specification