Micromachined devices

• US 6,684,698 B2
• Filed: 11/14/2002
• Issued: 02/03/2004
• 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:
  US10/294,107
• Publication Number:
  US 20030056589A1
• Time in Patent Office: 446 Days
• Field of Search: 735/040.4, 735/041.2, 735/041.3, 735/041.4, 735/041.5, 735/041.6, 735/143.2, 735/143.6, 361/283.1, 361/283.3
• US Class Current: 73/504.14
• CPC Class Codes: G01C 19/5719 using planar vibrating masses driven in a translation vibration along an axis

Abstract

A micromachined device has a body suspended over a substrate and movable in a plane relative to the substrate. The body has a perimeter portion, a first cross-piece portion extending from one part of the perimeter portion to another part of the perimeter portion to define at least first and second apertures, a first plurality of fingers extending along parallel axes from the perimeter portion into the first aperture, and a second plurality of fingers extending along parallel axes from the perimeter portion into the second aperture.

Claims

1. A micromachined device comprising:

a substrate;

a first body suspended in a plane over the substrate and movable in the plane along a first direction;

an anchored member, elongated next to a side of the first body along a second direction transverse to the first direction, the anchored member surrounded by the first body, the anchored member having first and second opposite ends in the lengthwise direction and having flexures extending from each end of the anchored member to the first body, the flexures allowing the first body to move in the first direction more easily than in the second direction, the member being anchored with at least one anchor positioned centrally along the anchored member between the first and second opposite ends.

2. The device of claim 1, further comprising a set of fingers fixed relative to the substrate, the first body including a plurality of fingers extending in the second direction and interdigitating with the fixed fingers such that movement of the fingers on the first body causes a change in capacitance between the plurality of fingers on the first body and the fixed fingers.

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

4. The device of claim 1, wherein the first body is symmetric about a center line parallel to the first direction and includes sides that extend generally along the first direction, the flexures being coupled to the sides of the first body, the attachment points between the flexures and the anchored member being closer to the sides than to the center line.

5. The device of claim 1, wherein the first body has fingers that are movable with the first body, the device further comprising stationary fingers that form a differential capacitor with the moving fingers.

6. The device of claim 1, wherein the first body is next to a first side, the device further comprising a second anchored member elongated along a second side of the first body, the second anchored member surrounded by the first body, the anchored member having first and second opposite ends in the lengthwise direction and having flexures extending from each end of the anchored member to the first body, the flexures allowing the first body to move in the first direction more easily than in the second direction, the member being anchored with at least one anchor positioned centrally along the anchored member between the first and second opposite ends.

7. The device of claim 6, wherein the first side of the body is parallel to the second side of the body.

8. The device of claim 1, wherein the first body is part of a sensor for sensing acceleration and that has fixed electrodes that are stationary relative to the substrate, the first body having electrodes that move with the first body relative to the fixed electrodes to cause a change in capacitance therebetween.

9. The device of claim 8, wherein the sensor is part of a gyroscope that has a dithered body coupled to the first body.

10. A micromachined device comprising:

a substrate;

a first body suspended in a plane over the substrate and movable in the plane along a first direction, the first body having a substantially rectangular perimeter portion;

an anchored member, elongated along a side of the substantially rectangular first body along a second direction transverse to the first direction, the anchored member having first and second opposite ends in the lengthwise direction and having flexures extending from each end of the anchored member to the first body, the flexures allowing the first body to move in the first direction more easily than in the second direction, the member being anchored with at least one anchor positioned centrally along the anchored member between the first and second opposite ends.

11. The device of claim 10, further comprising a set of fingers fixed relative to the substrate, the first body including a plurality of fingers extending in the second direction and interdigitating with the fixed fingers such that movement of the fingers on the first body causes a change in capacitance between the plurality of fingers on the first body and the fixed fingers.

12. The device of claim 10, further comprising a package, wherein the device is packaged in the package under ambient conditions.

13. The device of claim 10, wherein the first body is symmetric about a center line parallel to the first direction and includes sides that extend generally along the first direction, the flexures being coupled to the sides of the first body, the attachment points between the flexures and the anchored member being closer to the sides than to the center line.

14. The device of claim 10, wherein the first body has fingers that are movable with the first body, the device further comprising stationary fingers that form a differential capacitor with the moving fingers.

15. The device of claim 10, wherein the first body is part of a sensor for sensing acceleration and that has fixed electrodes that are stationary relative to the substrate, the first body having electrodes that move with the first body relative to the fixed electrodes to cause a change in capacitance therebetween.

16. The device of claim 15, wherein the sensor is part of a gyroscope that has a dithered body coupled to the first body.

17. A micromachined device comprising:

a substrate;

a first body suspended in a plane over the substrate and movable in the plane along a first direction, the first body having a substantially rectangular perimeter portion;

an anchored member, elongated along a first side of the substantially rectangular perimeter portion, and including multiple anchors with one near the side the anchor is next to along a second direction transverse to the first direction, the anchored member first and second opposite ends in the lengthwise direction and having flexures extending from each end of the anchored member to the first body, the flexures allowing the first body to move in the first direction more easily than in the second direction, the member being anchored with at least one anchor positioned centrally along the anchored member between the first and second opposite ends.

18. The device of claim 17, wherein one of the anchors is near an edge of the anchored member facing the first body.

19. The device of claim 17, further comprising a second anchored member elongated along a second side of the substantially rectangular perimeter portion, the second anchored member having first and second opposite ends in the lengthwise direction and having flexures extending from each end of the anchored member to the first body, the flexures allowing the first body to move in the first direction more easily than in the second direction, the member being anchored with at least one anchor positioned centrally along the anchored member between the first and second opposite ends.

20. The device of claim 19, wherein the first side of the body is parallel to the second side of the body.

21. The device of claim 17, wherein the first body is part of a sensor for sensing acceleration and that has fixed electrodes that are stationary relative to the substrate, the first body having electrodes that move with the first body relative to the fixed electrodes to cause a change in capacitance therebetween.

22. The device of claim 21, wherein the sensor is part of a gyroscope that has a dithered body coupled to the first body.