Micromachined cross-differential dual-axis accelerometer
First Claim
1. A micromachined accelerometer for sensing acceleration along first and second axes, comprising:
- at least one proof mass and one frame suspended above a substrate in a manner permitting movement of each proof mass relative to the substrate along the first axis in response to acceleration along the first axis and also permitting torsional movement of each proof mass relative to the substrate about a third axis perpendicular to the first and second axes in response to acceleration along the second axis, detection electrodes that move with each proof mass relative to stationary electrodes to form a plurality of capacitors each of which changes in capacitance both in response to movement of a proof mass along the first axis and in response to torsional movement of a proof mass about the third axis, and circuitry connected to the electrodes for providing output signals corresponding to acceleration along the first and second axes.
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Accused Products
Abstract
Micromachined accelerometer having one or more proof masses (16, 36, 37, 71, 72) mounted on one or more decoupling frames (17, 38, 39) or on a shuttle (73) such that the proof mass(es) can move along a first (y) axis in response to acceleration along the first axis while being constrained against movement along a second (x) axis and for torsional movement about a third (z) axis perpendicular to the first and second axes in response to acceleration along the second axis. Electrodes (26, 53, 54, 78, 79) that move with the proof mass(es) are interleaved with stationary electrodes (27, 56, 57, 81, 82) to form capacitors (A-D) that change in capacitance both in response to movement of the proof mass(es) along the first axis and in response to torsional movement of the proof mass(es) about the third axis, and circuitry (31-34) connected to the electrodes for providing output signals corresponding to acceleration along the first and second axes. The capacitances of two capacitors on each side of the second axis change in the same direction in response to acceleration along the first axis and in opposite directions in response to acceleration along the second axis. Signals from the capacitors that change capacitance in opposite directions both in response to acceleration along the first axis and in response to acceleration along the second axis are differentially combined to provide first and second difference signals, and the difference signals are additively and differentially combined to provide output signals corresponding to acceleration along the first and second axes.
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Citations
19 Claims
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1. A micromachined accelerometer for sensing acceleration along first and second axes, comprising:
- at least one proof mass and one frame suspended above a substrate in a manner permitting movement of each proof mass relative to the substrate along the first axis in response to acceleration along the first axis and also permitting torsional movement of each proof mass relative to the substrate about a third axis perpendicular to the first and second axes in response to acceleration along the second axis, detection electrodes that move with each proof mass relative to stationary electrodes to form a plurality of capacitors each of which changes in capacitance both in response to movement of a proof mass along the first axis and in response to torsional movement of a proof mass about the third axis, and circuitry connected to the electrodes for providing output signals corresponding to acceleration along the first and second axes.
- View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A micromachined accelerometer for sensing acceleration along first and second axes, comprising:
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at least one proof mass and one frame suspended above a substrate in a manner permitting movement of each proof mass relative to the substrate along the first axis in response to acceleration along the first axis and also permitting torsional movement of each proof mass relative to the substrate about a third axis perpendicular to the first and second axes in response to acceleration along the second axis, detection electrodes that move with each proof mass relative to stationary electrodes to form capacitors in the four quadrants defined by the first and second axes, with the capacitances of the two capacitors changing in the same direction in response to acceleration along the first axis and in opposite directions in response to acceleration along the second axis, and circuitry for differentially combining signals from capacitors that change capacitance in opposite directions both in response to acceleration along the first axis and in response to acceleration along the second axis to provide first and second difference signals, additively combining the difference signals to provide an output signal corresponding to acceleration along one of the axes, and differentially combining the difference signals to provide an output signal corresponding to acceleration along the other axis.
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Specification