Micromachined devices with stop members

• US 20020046602A1
• Filed: 12/17/2001
• Published: 04/25/2002
• Est. Priority Date: 09/02/1997
• Status: Active Grant

• Current Assignee: Donald W. Carow, John A. Geen
• Original Assignee: Donald W. Carow, John A. Geen
• Inventors: Geen, John A., Carow, Donald W.
• Granted Patent: US 6,487,908 B2
• Time in Patent Office: Days
• US Class Current: 73/504.02
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

A micromachined gyroscope has first and second coplanar bodies suspended over a substrate and movable in their plane relative to the substrate. The first body is dithered along a dither axis and is movable relative to the second body on the dither axis, but is rigidly connected for movement along an axis transverse to the dither axis. The second body is anchored so that it is substantially inhibited from moving along the dither axis, but can move with the first body along the transverse axis. The gyro has stop members and an anti-levitation system for preventing failure.

Claims

1. A micromachined device comprising:

a substrate;

a micromachined first body suspended over the substrate in a plane parallel to the substrate and movable in the plane relative to the substrate; and

a first stop member adjacent the first body and anchored to the substrate, the stop member having a first portion coplanar with the body for limiting motion in the plane of the body, and a second portion extending over the body for physically limiting movement of the body both orthogonal to the plane and away from the substrate.

2. The device of claim 1 wherein the first stop member is made of titanium tungsten.

3. The device of claim 1, further comprising a second body suspended over the substrate and coupled to the first body.

4. The device of claim 3, wherein the first body surrounds the second body.

5. The device of claim 3, wherein the second body surrounds the first body.

6. The device of claim 5, wherein the first stop member is in a region defined between the first body and the second body.

7. The device of claim 6, wherein the first stop member is free standing and coupled only to the substrate.

8. The device of claim 1, wherein the first portion and second portion are monolithic.

9. The device of claim 1, further comprising a second stop member adjacent the first body and spaced from the first stop member, the second stop member being substantially the same as the first stop member.

10. The device of claim 9, wherein the body is generally rectangular and the first and second stop members are adjacent the body near different corners of the body.

11. The device of claim 10, further comprising third and fourth stop members, each substantially similar to the first stop member, such that one stop member is near each corner.

12. The device of claim 11, further comprising:

a second body suspended over the substrate and coupled to the first body.

13. The device of claim 12, wherein the second body surrounds the first body.

14. The device of claim 13, wherein the first through fourth stop members are in a region defined between the first body and the second body.

15. The device of claim 11, wherein the first through fourth stop members are each free-standing and only anchored to the substrate.

16. The device of claim 1, further comprising a dither drive for dithering the body in the plane along a first direction, the stop member physically blocking movement in a second direction orthogonal to the first direction.

18. The device of claim 17, further comprising means for dithering the body in the first direction.

17. A micromachined device comprising:

a substrate;

a micromachined first body suspended over the substrate in a plane parallel to the substrate and movable in the plane relative to the substrate along a first direction; and

means for physically limiting motion of the body in the plane along a second direction orthogonal to the first direction and in a direction orthogonal to the plane and away from the substrate.