Tunneling-based rate gyros with simple drive and sense axis coupling

• US 6,109,105 A
• Filed: 11/04/1998
• Issued: 08/29/2000
• Est. Priority Date: 09/01/1995
• Status: Expired due to Term

• Current Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Original Assignee: Hughes Electronics Corporation (Rtx Corporation)
• Inventors: Challoner, Dorian, Atkinson, Gary M., Sunada, Wallace, Kubena, Randall L.
• Primary Examiner(s): Kwok, Helen C.
• Application Number:
  US09/186,174
• Time in Patent Office: 664 Days
• Field of Search: 73/504.12, 73/504.15, 73/504.18, 73/504.02, 73/504.04, 73/514.15, 73/514.16, 73/514.21, 73/514.29, 73/514.36, 73/510 , 73/862.635
• US Class Current: 73/504.15
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces
• CPC Class Codes: G01P 15/0894 by non-contact electron transfer, i.e. electron tunneling
• CPC Class Codes: G01P 15/131 with electrostatic counterbalancing means
• CPC Class Codes: G01P 15/18 in two or more dimensions
• CPC Class Codes: G01P 21/00 Testing or calibrating of apparatus or devices covered by the preceding groups

Abstract

Various structures for cantilever beam tunneling rate gyro devices formed on a single substrate are disclosed. A cantilever electrode having a plurality of portions extending from the substrate with one end of the cantilever is suspended above the substrate at a distance from a tunneling electrode so that a tunneling current flows through the cantilever and tunneling electrode in response to an applied bias voltage. The cantilever and tunneling electrodes form a circuit that produces an output signal. A force applied to the sensor urges the cantilever electrode to deflect relative to the tunneling electrode to modulate the output signal. The output signal is a control voltage that is applied between the cantilever electrode and a control electrode to maintain a constant tunneling current. In the preferred embodiment, two cantilever portions extend from the wafer surface forming a Y-shape. In a further embodiment, a strap is fabricated on the cantilever electrode. In an alternate embodiment, a ridge emitter is formed such that it remains under the cantilever electrode during lateral motion of the cantilever. In an alternate embodiment, a cantilever having a varying width is fabricated.

Claims

1. A tunneling rotation sensor, comprising:

a substrate;

a cantilever having a portion extending from said substrate and a cantilever arm positioned away from said substrate, said cantilever arm comprising a first section and a second section,

said cantilever arm further comprising flexible material and being constructed such that;

a) said first section is wider than said second section and said first section is closer to said portion extending from said substrate than said second section;

b) said cantilever arm is capable of deflection toward and away from said substrate; and

c) said first section is more restricted than said second section from making lateral movements, and

a tunneling electrode on said substrate beneath said first section such that a tunneling gap through which a current can flow is formed between said tunneling electrode and said first section.

2. The tunneling rotation sensor of claim 1 wherein said current flows through said cantilever arm when a voltage is established between said cantilever arm and said tunneling electrode.

3. The tunneling rotation sensor of claim 2, further comprising a first lateral control electrode and a second lateral control electrode both disposed on said substrate adjacent said second section of said cantilever arm.

4. The tunneling rotation sensor of claim 3, wherein said second section of said cantilever arm oscillates in directions not modifying said deflection when a corresponding voltage is established between said first and second lateral control electrodes and said cantilever arm such that when said sensor is rotated at a rate about an axis defined by said cantilever arm a Corlolis force is exerted on said cantilever arm in proportion to said rate.