Silicon integrated angular rate sensor
First Claim
1. A motion sensor comprising:
- a support substrate formed of silicon having a crystalline orientation that defines a plane, defines a X-axis parallel to the plane, and defines a Y-axis perpendicular to the X-axis and parallel to the plane;
a silicon sensing ring formed within and supported by the substrate and having a flexural resonance;
at least one drive electrode comprising drive capacitive plates for applying electrostatic force on the ring to cause the ring to resonate;
at least one sense electrode comprising sense capacitive plates for sensing a change in capacitance indicative of vibration nodes of resonance of the ring so as to sense motion;
a plurality of silicon support springs connecting the substrate to the ring, wherein the support springs are formed as eight minor image pairs of springs, wherein the support springs each comprise a first spring connecting the substrate to the ring and a second spring connecting the substrate to the ring that is a minor image of the first spring, wherein each first spring and second spring comprise a first straight beam having a radial orientation relative to the sensing ring and the crystalline orientation of the silicon, and a second straight beam oriented at an angle relative to the first straight beam to substantially match a modulus of elasticity of the silicon support springs; and
an electrical connection comprising at least one external tether in contact with the ring.
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Accused Products
Abstract
A motion sensor in the form of an angular rate sensor and a method of making a sensor are provided and includes a support substrate and a silicon sensing ring supported by the substrate and having a flexive resonance. Drive electrodes apply electrostatic force on the ring to cause the ring to resonate. Sensing electrodes sense a change in capacitance indicative of vibration modes of resonance of the ring so as to sense motion. A plurality of silicon support rings connect the substrate to the ring. The support rings are located at an angle to substantially match a modulus of elasticity of the silicon, such as about 22.5 degrees and 67.5 degrees, with respect to the crystalline orientation of the silicon.
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Citations
30 Claims
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1. A motion sensor comprising:
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a support substrate formed of silicon having a crystalline orientation that defines a plane, defines a X-axis parallel to the plane, and defines a Y-axis perpendicular to the X-axis and parallel to the plane; a silicon sensing ring formed within and supported by the substrate and having a flexural resonance; at least one drive electrode comprising drive capacitive plates for applying electrostatic force on the ring to cause the ring to resonate; at least one sense electrode comprising sense capacitive plates for sensing a change in capacitance indicative of vibration nodes of resonance of the ring so as to sense motion; a plurality of silicon support springs connecting the substrate to the ring, wherein the support springs are formed as eight minor image pairs of springs, wherein the support springs each comprise a first spring connecting the substrate to the ring and a second spring connecting the substrate to the ring that is a minor image of the first spring, wherein each first spring and second spring comprise a first straight beam having a radial orientation relative to the sensing ring and the crystalline orientation of the silicon, and a second straight beam oriented at an angle relative to the first straight beam to substantially match a modulus of elasticity of the silicon support springs; and an electrical connection comprising at least one external tether in contact with the ring. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30)
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Specification