Angular rate sensor
First Claim
1. An angular rate sensor including a substantially planar vibratory resonator having a substantially ring or hoop-like shape structure with inner and outer peripheries extending around a common axis, electrostatic drive means for causing the resonator to vibrate, support means including a plurality of flexible support beams for supporting the resonator and for allowing the resonator to vibrate in response to the electrostatic drive means, in a substantially undamped oscillation mode such as to permit the resonator to move relative to the support means in response to turning rate, which said support beams and said resonator are made from crystalline silicon, and electrostatic sensing means for sensing movement of the resonator, which said electrostatic drive means and electrostatic sensing means include plate-like elements made from crystalline silicon having surfaces located substantially normal to the plane of the resonator at a spacing from an adjacent outer periphery of the resonator, with a ratio of the thickness of the resonator at said adjacent periphery to a width of the spacing between said resonator periphery and said plate-like element surfaces being in the range of from 10:
- 1 to 40;
1 to maximise a capacitance between the resonator and the plate-like elements and thereby optimising a drive force on the resonator for a given applied voltage, and to optimise the sensitivity of the electrostatic sensing means.
5 Assignments
0 Petitions
Accused Products
Abstract
An angular rate sensor or gyro includes a ring-like resonator (1) mounted by support beams (2) extending from the inner periphery of the ring (1) to a boss (4) on a base (3). The support beams (2) are flexible and allow the resonator (1) to vibrate in response to an electrostatic drive (6, 8) in a substantially undamped oscillation mode to permit the resonator to move relative to the support in response to turning rate. The support beams (2) and resonator (1) are made from crystalline silicon. Electrostatic sensors (7, 9) are provided for sensing movement of the resonator (1). The drive (6, 8) and sensors (7, 9) have plate-like elements made from crystalline silicon having surfaces located substantially normal to the plane of the resonator (1) at a spacing from the adjacent outer periphery of the resonator (1). The ratio of the thickness of the resonator (1) at the outer periphery (1b) to the width of the spacing (11) between the periphery (1b) and the element surfaces (10) is in the range of from 10:1 to 40:1.
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Citations
9 Claims
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1. An angular rate sensor including a substantially planar vibratory resonator having a substantially ring or hoop-like shape structure with inner and outer peripheries extending around a common axis, electrostatic drive means for causing the resonator to vibrate, support means including a plurality of flexible support beams for supporting the resonator and for allowing the resonator to vibrate in response to the electrostatic drive means, in a substantially undamped oscillation mode such as to permit the resonator to move relative to the support means in response to turning rate, which said support beams and said resonator are made from crystalline silicon, and electrostatic sensing means for sensing movement of the resonator, which said electrostatic drive means and electrostatic sensing means include plate-like elements made from crystalline silicon having surfaces located substantially normal to the plane of the resonator at a spacing from an adjacent outer periphery of the resonator, with a ratio of the thickness of the resonator at said adjacent periphery to a width of the spacing between said resonator periphery and said plate-like element surfaces being in the range of from 10:
- 1 to 40;
1 to maximise a capacitance between the resonator and the plate-like elements and thereby optimising a drive force on the resonator for a given applied voltage, and to optimise the sensitivity of the electrostatic sensing means. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
- 1 to 40;
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9. An angular rate sensor comprising:
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a substantially planar vibratory resonator having a substantially ring or hoop-like shape structure with inner and outer peripheries extending around a common axis;
an electrostatic drive causing the resonator to vibrate;
a plurality of flexible support beams for supporting the resonator and for allowing the resonator to vibrate in response to the electrostatic drive, in a substantially undamped oscillation mode such as to permit the resonator to move relative to the support in response to turning rate, which said support beams and said resonator are made from crystalline silicon; and
electrostatic sensor sensing movement of the resonator, which said electrostatic drive and electrostatic sensor include plate-like elements made from crystalline silicon having surfaces located substantially normal to the plane of the resonator at a spacing from an adjacent outer periphery of the resonator, with a ratio of the thickness of the resonator at said adjacent periphery to a width of the spacing between said resonator periphery and said plate-like element surfaces being in the range of from 10;
1 to 40;
1 to maximise a capacitance between the resonator and the plate-like elements and thereby optimising a drive force on the resonator for a given applied voltage, and to optimise the sensitivity of the electrostatic sensor.
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Specification