Microgyroscope with integrated vibratory element

• US 6,758,093 B2
• Filed: 12/03/2002
• Issued: 07/06/2004
• Est. Priority Date: 07/08/1999
• Status: Expired due to Term

• Current Assignee: California Institute of Technology
• Original Assignee: California Institute of Technology
• Inventors: Rodger, Damien C., Gutierrez, Roman C., Tang, Tony K.
• Primary Examiner(s): KWOK, HELEN C
• Application Number:
  US10/309,538
• Publication Number:
  US 20030074967A1
• Time in Patent Office: 581 Days
• Field of Search: 735/040.2, 735/040.4, 735/041.2, 735/041.4, 735/041.5, 735/041.6
• US Class Current: 73/504.02
• CPC Class Codes: G01C 19/56 Turn-sensitive devices using vibrating masses, e.g. vibratory angular rate sensors based on Coriolis forces

Abstract

A microgyroscope having a suspended vertical post uses the Coriolis force to detect the rotation rate. The microgyroscope consists of a single vertical post which is the rotation rate sensing element. The vertical post is formed from the same silicon wafers as the rest of the microgyroscope. A first portion of the vertical post and the clover-leaf structure are made from a first silicon wafer. A second portion of the vertical post and the baseplate are made from a second silicon wafer. The two portions are then bonded together to from the clover-leaf gyroscope with an integrated post structure.

Claims

1. A method comprising:

forming a first section of a microgyroscope having a first portion of a post and a first plurality of capacitors from a first substrate;

forming a second section of the microgyroscope having a second portion of the post and a second plurality of capacitors from a second substrate; and

attaching the first portion of the post to the second portion of the post; and

aligning the first plurality of capacitors to the second plurality of capacitors, such that the first plurality of capacitors are electrically isolated from the second plurality of capacitors.

2. The method of claim 1, further comprising using at least one of the first plurality of capacitors and the second plurality of capacitors to provide electrostatic actuation of the post.

3. The method of claim 1, wherein forming at least one of the first and second sections of the microgyroscope comprises forming the at least one section from a silicon substrate.

4. The method of claim 1, further comprising bonding the first and second portions of the post at approximately a mid-point of the post.

5. The method of claim 4, wherein forming at least one of the first plurality and second plurality of capacitors comprises forming a clover-leaf shaped structure around the post.

6. The method of claim 1, further comprising forming flanges on at least one of the first portion of the post and the second portion of the post.

7. The method of claim 1, wherein bonding the first portion of the post to the second portion of the post comprises metal-to-metal bonding.

8. A microgyroscope comprising:

a post comprising first and second portions, the first portion being formed from a first substrate, the second portion being formed from a second substrate, the first portion of the post being bonded to the second portion;

a first plurality of capacitors formed from the first substrate; and

a baseplate formed from the second substrate, the first plurality of capacitors being bonded to the baseplate formed from the second substrate, at least one of the first plurality of capacitors and the baseplate being operative to provide electrostatic actuation of the post.

9. The microgyroscope of claim 8, wherein the first plurality of capacitors are formed in a clover-leaf shape and positioned around the first portion of the post.

10. The microgyroscope of claim 9, wherein the baseplate includes a second plurality of capacitors positioned around the second portion of the post.

11. The microgyroscope of claim 8, wherein at least one of the first portion of the post and the second portion of the post comprises flanges.

12. The microgyroscope of claim 8, further comprising metal-to-metal bonding between the first portion of the post and the second portion of the post.

13. The microgyroscope of claim 8, wherein the first portion of the post and second portion of the post are approximately equal in length and bonded at approximately a mid-portion of the microgyroscope.

14. The microgyroscope of claim 8, wherein a longitudinal axis of the first plurality of capacitors is parallel to a longitudinal axis of the post in a resting state.

15. The microgyroscope of claim 8, wherein the first and second substrates are silicon substrates.

16. The microgyroscope of claim 8, wherein the post is free to move in x and y directions, which define a plane that is parallel to the post.

17. The microgyroscope of claim 8, being operable to detect forces in three directions.

18. The microgyroscope of claim 8, wherein each capacitor of the first plurality of capacitors are equidistant from the post.

19. The microgyroscope of claim 8, wherein the baseplate comprises a second plurality of capacitors which are electrically isolated from the first plurality of capacitors.