MEMS MICROMIRROR AND MICROMIRROR ARRAY

• US 20100302617A1
• Filed: 05/28/2010
• Published: 12/02/2010
• Est. Priority Date: 06/01/2009
• Status: Active Grant

• Current Assignee: Alberta Inc.
• Original Assignee: Tiansheng Zhou
• Inventors: ZHOU, Tiansheng
• Granted Patent: US 8,238,018 B2
• Time in Patent Office: Days
• US Class Current: 359/291
• CPC Class Codes: G02B 26/08 for controlling the direction of light in light guides G02B6/35
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means

Abstract

A micro-electro-mechanical-system (MEMS) micromirror array has an array of micromirrors on a support structure. Each micromirror is pivotally attached to the support structure by a resilient structure. The resilient structure defines a pivot axis. There is an array of electrostatic actuators for pivotally driving the array of micromirrors about the pivot axis. Each electrostatic actuator comprises a first part carried by the support structure, and a second part carried by the corresponding micromirror. An electrostatic sink is mounted to the support structure that shields at least one micromirror from spurious electrostatic actuation.

Claims

1. A micro-electro-mechanical-system (MEMS) micromirror array, comprising:

an array of micromirrors on a support structure, each micromirror being pivotally attached to the support structure by a resilient structure, the resilient structure defining a pivot axis;

an array of electrostatic actuators for pivotally driving the array of micromirrors about the pivot axis, each electrostatic actuator comprising a first part carried by the support structure, and a second part carried by the corresponding micromirror; and

an electrostatic sink mounted to the support structure that shields at least one micromirror from spurious electrostatic actuation.

2. The MEMS micromirror array of claim 1, wherein the electrostatic sink is an electrical ground.

3. The MEMS micromirror array of claim 1, wherein the electrostatic sink is a physical barrier.

4. The MEMS micromirror array of claim 1, wherein the electrostatic sink is an electrode on the support structure.

5. The MEMS micromirror array of claim 1, wherein the electrostatic sink shields at least one micromirror from spurious actuation by an adjacent electrostatic actuator.

6. The MEMS micromirror array of claim 1, wherein the electrostatic sink shields at least one micromirror from accumulated electrostatic charge on the support structure.

7. The MEMS micromirror array of claim 1, wherein the electrostatic actuator is a vertical comb drive.

8. The MEMS micromirror array of claim 7, wherein one of the first part of the vertical comb drive or the second part of the vertical comb drive comprises fingers that are enclosed within an outer perimeter of the other of the first part or the second part.

9. The MEMS micromirror of claim 8, wherein the fingers are carried by a carrier portion that is perpendicular to the pivot axis, the carrier portion being connected to an external portion that is outside the outer perimeter of the other of the first part and the second part.

10. The MEMS micromirror of claim 8, wherein the fingers are parallel to the pivot axis.

11. The MEMS micromirror array of claim 8, wherein the fingers are angled relative to the pivot axis.

12. The MEMS micromirror array of claim 1, wherein each micromirror is symmetrical about the pivot axis.

13. The MEMS micromirror array of claim 1, wherein the micromirrors in the array are staggered perpendicularly to the pivot axis.

14. The MEMS micromirror array of claim 1, further comprising a cavity between the micromirrors and the support structure.

15. The MEMS micromirror array of claim 14, further comprising a physical barrier separating adjacent cavities to prevent pneumatic actuation of adjacent micromirrors due to movement of an adjacent micromirror.

16. The MEMS micromirror array of claim 15, wherein the physical barrier comprises an intermediate support structure.

17. The MEMS micromirror array of claim 1, wherein the micromirrors are formed from a first layer of material, the electrostatic sink is formed from a second layer of material, and the support structure is formed from a third layer of material.

18. The MEMS micromirror array of claim 1, wherein at least one micromirror comprises a second electrostatic actuator for pivoting the micromirror about a second pivot axis.

19. The MEMS micromirror array of claim 1, wherein the resilient structure comprises a first portion having an I beam connected to a composite structure, and a second portion that is symmetrical to the first portion, the first and second portions defining the pivot axis.

20. The MEMS micromirror array of claim 19, wherein the composite structure is one of one or more dual I beam structures, one or more V-shaped structures, and combinations thereof.

21. A MEMS micromirror structure, comprising:

a micromirror mounted on a support structure by a resilient structure;

an electrostatic actuator for moving the micromirror relative to the support structure, the electrostatic actuator comprising a first part carried by the support structure, and a second part carried by the corresponding micromirror;

a latch mounted to the support structure by a movable portion that moves in response to an applied voltage between a latching position and a release position as the applied voltage is varied, wherein, in the latching position, the latch secures the micromirror in a desired position.

22. The MEMS structure of claim 21, wherein the movable portion is a thermal arched beam actuator.

23. The MEMS structure of claim 21, wherein the movable portion comprises first and second parallel thermal connectors that expand at different rates in response to the applied voltage.

24. A MEMS micromirror structure, comprising:

a micromirror mounted on a support structure by a resilient structure;

an electrostatic actuator for pivotally driving the micromirror, the electrostatic actuator comprising a first part carried by the support structure, and a second part carried by the corresponding micromirror;

the resilient structure comprising a first portion and a second portion that is symmetrical to the first portion, each of the first portion and the second portion comprising an I beam connected to a composite structure.

25. The MEMS micromirror array of claim 24, wherein the composite structure is one of one or more dual I beam structures, one or more V-shaped structures, and combinations thereof.

26. A MEMS micromirror, comprising:

a micromirror mounted on a support structure by a resilient structure, the resilient structure permitting movement along an axis that is perpendicular to the support structure and resisting movement in any direction perpendicular to the axis;

an electrostatic combdrive actuator having a first part mounted on the support structure, and a second part mounted on the micromirror, the first part and the second part providing an actuating force to the micromirror to move the micromirror along the axis.

27. The MEMS micromirror of claim 26, wherein the electrostatic combdrive actuator comprises more than one first and second parts spaced evenly about an outer perimeter of the micromirror.

28. The MEMS micromirror of claim 26, wherein the resilient structure comprises more than one resilient structures spaced evenly about an outer perimeter of the micromirror.

29. The MEMS micromirror of claim 26, wherein the support structure is formed from a first layer of material, the first part of the electrostatic combdrive is formed from a second layer of material, and the micromirror, the second part of the electrostatic combdrive and the resilient structure is formed from a third layer of material.