Micromachined gyros

• US 6,505,511 B1
• Filed: 08/25/2000
• Issued: 01/14/2003
• Est. Priority Date: 09/02/1997
• Status: Expired due to Term

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Geen, John A., Carow, Donald W.
• Primary Examiner(s): CHAPMAN JR, JOHN E
• Application Number:
  US09/645,199
• Time in Patent Office: 872 Days
• Field of Search: 735/041.2, 735/041.3, 735/041.4, 735/041.5, 735/041.6, 735/040.4
• US Class Current: 73/504.12
• 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 first body suspended over the substrate and movable relative to the substrate such that the first body can be dithered along a dither axis;

a second body suspended over the substrate, the fist and second bodies being coplanar in a first plane parallel to the substrate; and

a connection structure between the first body and the second body, the connection structure including a first pivoting beam, a second pivoting beam, flexures extending from the first body to the first and second pivoting beams, a beam connecting the first and second pivoting beams, and first and second structures connecting the first and second pivoting to the second body, such that the first and second pivoting beams pivot where connected to the respective connection structures in response to dithering movement by the first body.

2. The device of claim 1, wherein the first body includes a first plurality of fingers extending in parallel away from the body and coplanar with the body and the second body includes a second plurality of fingers parallel to the first plurality of fingers and interdigitating with the first plurality of fingers, the device further comprising a first conductive member formed on the substrate under a first group of the first and second plurality of fingers, the first conductive member electrically coupled to the second plurality of fingers to prevent the first body from levitating relative to the substrate.

3. The device of claim 1, further comprising a stop member adjacent the first body and anchored to the substrate, the stop member having a first portion coplanar with the first body for limiting motion in the plane of the first body, and a second portion integral with the first portion and extending over the first body for physically limiting movement of the first body orthogonal to the plane and away from the substrate.

4. The device of claim 1, wherein the first body is proximate an electrode for causing the first body to dither laterally along the dither axis.

5. The device of claim 4, wherein the first body includes a first plurality of fingers and the electrode includes a second plurality of fingers interdigitating with the first plurality of fingers for dithering the first body.

6. The device of claim 1, further comprising a package, wherein the device is packaged in the package under ambient conditions.

7. A micromachined device comprising:

a substrate;

a first body suspended over the substrate and movable relative to the substrate such that the first body can be dithered along a dither axis;

a second body suspended over the substrate, the first and second bodies being coplanar in a first plane parallel to the substrate; and

a coupling structure connecting the first and second bodies, the coupling structure including first and second elongated arms that together extend substantially along the length of the first body along a direction perpendicular to the dither axis, the first and second arms being connected together through a coupling beam that is shorter than the two arms.

8. The device of claim 7, wherein each arm is connected to the first body through perpendicular flexures that define a pivot point.

9. The device of claim 7, wherein the first body includes a first plurality of fingers extending in parallel away from the body and coplanar with the body and the second body includes a second plurality of fingers parallel to the first plurality of fingers and interdigitating with the first plurality of fingers, the device further comprising a first conductive member formed on the substrate under a first group of the first and second plurality of fingers, the first conductive member electrically coupled to the second plurality of fingers to prevent the first body from levitating relative to the substrate.

10. The device of claim 7, further comprising a stop member adjacent the first body and anchored to the substrate, the stop member having a first portion coplanar with the first body for limiting motion in the plane of the first body, and a second portion integral with the first portion and extending over the first body for physically limiting movement of the first body orthogonal to the plane and away from the substrate.

11. The device of claim 7, wherein the first body is proximate an electrode for causing the first body to dither laterally along the dither axis.

12. The device of claim 11, wherein the first body includes a first plurality of fingers and the electrode includes a second plurality of fingers interdigitating with the first plurality of fingers for dithering the first body.

13. The device of claim 7, further comprising a package, wherein the device is packaged in the package under ambient conditions.

14. The device of claim 7, wherein the coupling beam is narrower than each of the first and second elongated arms.

15. A micromachined device comprising:

a substrate;

a first body in a plane over the substrate;

a second body suspended in the plane and movable along a first direction in the plane relative to the substrate and to the first body;

a connection structure between the first body and the second body, the connection structure including;

a first beam,

a second beam,

first and second flexures extending from the second body to the first and second beams, and

a connecting beam connecting the first and second beams, the first and second beams pivoting where connected to the respective first and second flexures in response to movement along the first axis by the second body.

16. The device of claim 15, wherein the first and second flexures are parallel to the first direction.

17. The device of claim 15, wherein the first and second flexures are perpendicular to the first direction.