Tunneling sensor with linear force rebalance and method for fabricating the same
First Claim
1. A tunneling sensor with linear force rebalance, said tunneling sensor comprising:
- a substrate having an opening therein;
a plate electrode disposed within said opening of said substrate and attached to said substrate via a pair of flexures disposed on opposite sides of said plate electrode in a manner providing for rotation of said plate electrode about an axis of rotation lying between a first and a second end of said plate electrode, said plate electrode being unbalanced about said axis of rotation and having a tunnel-effect contact formed thereon;
a pair of co-planar torque rebalance bridge electrodes opposite one face of said plate electrode, a first torque rebalance bridge electrode in said pair being disposed proximate said first end of said plate electrode, a second torque rebalance bridge electrode in said pair being disposed proximate said second end of said plate electrode;
a tunnel-effect tip, said tunnel-effect tip being disposed proximate said tunnel-effect contact;
means for electrically biasing said tunnel-effect contact and said tunnel-effect tip;
means for sensing a tunnel current between said tunnel-effect contact and said tunnel-effect tip; and
feedback means for processing said tunnel current and electrically exciting said pair of torque rebalance bridge electrodes with complementary rebalance voltages derived from said processed tunnel current so as to generate an electrostatic rebalance torque upon said plate electrode about said rotational axis that is linearly related to an imbalance torque experienced by said plate electrode about said rotational axis upon acceleration of said plate electrode in a direction normal thereto.
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Accused Products
Abstract
A tunneling sensor is disclosed having a pair of force rebalance capacitors that are used in a push-pull relationship so as to provide a rebalance force that is a linear function of applied rebalance voltages, which leads to an output voltage that is linearly related to input acceleration. The tunneling sensor comprises a plate electrode that is formed from and attached to a silicon substrate by a pair of torsional flexures, which provide an axis of rotation for the plate electrode. A pendulous mass is formed on a first end of the plate electrode, and a tunnel-effect contact is formed on a second end of the plate electrode. A pair of torque rebalance bridge electrodes are formed on the substrate so as to span the plate electrode. A tunnel-effect tip is formed on the substrate so as to be proximate the tunnel-effect contact and in line with the rotational path that the tunnel-effect contact takes when the plate electrode is rotated.
42 Citations
16 Claims
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1. A tunneling sensor with linear force rebalance, said tunneling sensor comprising:
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a substrate having an opening therein; a plate electrode disposed within said opening of said substrate and attached to said substrate via a pair of flexures disposed on opposite sides of said plate electrode in a manner providing for rotation of said plate electrode about an axis of rotation lying between a first and a second end of said plate electrode, said plate electrode being unbalanced about said axis of rotation and having a tunnel-effect contact formed thereon; a pair of co-planar torque rebalance bridge electrodes opposite one face of said plate electrode, a first torque rebalance bridge electrode in said pair being disposed proximate said first end of said plate electrode, a second torque rebalance bridge electrode in said pair being disposed proximate said second end of said plate electrode; a tunnel-effect tip, said tunnel-effect tip being disposed proximate said tunnel-effect contact; means for electrically biasing said tunnel-effect contact and said tunnel-effect tip; means for sensing a tunnel current between said tunnel-effect contact and said tunnel-effect tip; and feedback means for processing said tunnel current and electrically exciting said pair of torque rebalance bridge electrodes with complementary rebalance voltages derived from said processed tunnel current so as to generate an electrostatic rebalance torque upon said plate electrode about said rotational axis that is linearly related to an imbalance torque experienced by said plate electrode about said rotational axis upon acceleration of said plate electrode in a direction normal thereto. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16)
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Specification