Micromachined devices with apertures

• US 20030200806A1
• Filed: 04/01/2003
• Published: 10/30/2003
• Est. Priority Date: 09/02/1997
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Analog Devices, Inc.
• Inventors: Geen, John A., Carow, Donald W.
• Granted Patent: US 6,925,877 B2
• Time in Patent Office: Days
• 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 body suspended over the substrate in a plane parallel to the substrate and movable in the plane relative to the substrate, the body having;

a perimeter portion,

a first cross-piece extending from one part of the perimeter portion to another part of the perimeter portion to at least partly define at least first and second apertures in the body in the plane,

a first plurality of fingers extending in parallel in the plane and into the first aperture, and

a second plurality of fingers extending in parallel in the plane and into the second aperture.

2. The device of claim 1, wherein the perimeter portion is generally rectangular, and the cross-piece forms two generally rectangular parts.

3. The device of claim 1, further comprising a second cross-piece extending across the perimeter portion, the first and second cross-pieces at least in part defining first, second, and third apertures.

4. The device of claim 1, wherein the body is movable with a dithering motion along a first direction, the first and second apertures being elongated along a second direction perpendicular to the first direction, the fingers being parallel to the first direction.

5. The device of claim 1, further comprising stationary fingers anchored to the substrate and interdigitating with the first plurality of fingers.

6. The device of claim 5, further comprising a dither drive coupled to the stationary fingers for providing a signal to cause the body to dither along a dither axis that is parallel to the direction of the first plurality of fingers.

7. The device of claim 1, further comprising stationary fingers anchored to the substrate and interdigitating with the first plurality of fingers to form capacitive sensing cells.

8. The device of claim 7, further comprising sensing circuitry for sensing movement of the first and second pluralities of fingers relative to the stationary fingers.

9. The device of claim 1, wherein the first plurality of fingers interdigitates with at least one stationary finger used to drive the body in an oscillating manner along a dither axis, and wherein the second plurality of fingers interdigitate with at least one stationary finger for sensing the dithering motion of the body along the dither axis, each aperture having fingers that are used only for driving or sensing.

10. The device of claim 1, wherein the first and second apertures each have some fingers that are used for driving the body in an oscillating manner along a dither axis, and other fingers that are used for sensing a dithering motion of the body along the dither axis.

11. The device of claim 1, further comprising at least one connecting structure extending from the perimeter portion to the first cross piece and perpendicular to the cross-piece to further define at least a third aperture.

12. The device of claim 11, wherein the body is dithered in a first direction, the first plurality of fingers being used to dither the body, the third aperture including a third plurality of fingers extending therein and used for sensing the dithering motion.

13. The device of claim 1, wherein the body includes n parallel cross-pieces to at least partly define at least n+1 apertures.

14. The device of claim 13, wherein each of the n+1 apertures has inwardly extending movable fingers, and within each aperture are stationary fingers that are not movable relative to the substrate and that interdigitate with the movable fingers, the stationary fingers being driven to cause the body to dither along a dither axis.

15. A micromachined device comprising:

a substrate;

a body suspended over the substrate in a plane parallel to the substrate and movable in the plane relative to the substrate, the body having a generally rectangular shape with a rectangular perimeter and having openings formed in the interior of the body, each of the openings having fingers extending along parallel axes into the opening.

16. The device of claim 15, further comprising stationary fingers that are not movable relative to the substrate for interdigitating with each of the sets of fingers that extend into openings.

17. The device of claim 16, further comprising a dither drive mechanism coupled to at least some of the stationary fingers for providing a signal to cause the body to dither along a dither axis.

18. The device of claim 16, further comprising sensing circuitry for sensing movement of the fingers relative to the stationary fingers.

19. The device of claim 15, wherein at least one opening includes fingers that are used for driving the body in an oscillating manner along a dither axis, and at least one other opening includes fingers that are used for sensing the dithering motion of the body along the dithering axis.

20. The device of claim 19, wherein each opening has only fingers that are used either for driving or sensing, but not both driving and sensing.

21. The device of claim 15, wherein at least one opening has some fingers that are used for driving the body in an oscillating manner along the dithering axis, and other fingers that are used for sensing the dithering motion of the body along the dithering axis.

22. The device of claim 16, wherein the openings are contoured to be only slightly larger than the size needed to provide the fingers and the stationary fingers.

23. The device of claim 22, wherein the openings have 12 sides except for the fingers.