Deformable MEMS mirror with membrane actuated by application of torque

• US 6,998,758 B2
• Filed: 06/05/2003
• Issued: 02/14/2006
• Est. Priority Date: 06/05/2003
• Status: Active Grant

• Current Assignee: Alcatel-Lucent USA, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Lopez, Omar D., Pardo, Flavio, Simon, Maria E., Aksyuk, Vladimir A.
• Primary Examiner(s): TAMAI, KARL I
• Application Number:
  US10/455,082
• Publication Number:
  US 20040245888A1
• Time in Patent Office: 985 Days
• Field of Search: 310/309, 318/116, 385/18, 359223-225, 359/291
• US Class Current: 310/309
• CPC Class Codes: G02B 26/06 for controlling the phase of light G02B26/08 takes precedence , measuring optical phase difference G01J9/00

Abstract

A MEMS device having a deformable mirror. In a representative embodiment, the MEMS device includes a deformable membrane supporting a plurality of light-reflecting segments that form the deformable mirror. One or more actuators, at least one of which is configured to apply torque to a side of the membrane, are used to deform the membrane. Membrane deformation causes the segments to change orientation and thereby change the shape of the minor. A representative MEMS device of the invention enables segment displacements in two directions and thereby realizes effective mirror curvature values in the range from about −2 mm⁻¹ to about +2 mm⁻¹.

Claims

1. A MEMS device, comprising:

a deformable membrane movably connected to a support structure; and

one or more actuators configured between the membrane and the support structure, each actuator adapted to apply torque to the membrane to change the shape of the membrane, wherein at least one of the one or more actuators is adapted to rotate a torsional member attached to the membrane about a longitudinal axis of said torsional member said rotation causing the torsional member to apply torque to the membrane.

2. The device of claim 1, wherein each actuator is configured to apply torque to a side of the membrane.

3. The device of claim 1, wherein, when the membrane is deformed by the one or more actuators, the membrane deformation provides a counteracting force for said actuators.

4. The device of claim 1, wherein:

the one or more actuators comprise four actuators grouped into two actuator pairs located at opposite sides of the membrane; and

each actuator pair has actuators located at a single side of the membrane.

5. The device of claim 1, wherein the one or more actuators include a first actuator, comprising a movable portion rotatably connected between the support structure and a first side of the membrane, wherein rotation of the movable portion generates torque for the first side of the membrane.

6. The device of claim 5, wherein the first actuator further comprises first and second electrodes fixedly attached to the support structure, wherein:

when a first voltage differential is applied between the movable portion and the first electrode, the movable portion rotates in a first direction; and

when a second voltage differential is applied between the movable portion and the second electrode, the movable portion rotates in a direction opposite to the first direction.

7. The device of claim 6, wherein the first actuator is a comb drive actuator.

8. The device of claim 5, wherein the movable portion is supported by first and second members, the first member connected between the movable portion and the support structure and the second member connected between the movable portion and the first side of the membrane, the first and second members defining an axis of rotation for the movable portion.

9. The device of claim 1, wherein the membrane has a reflective surface.

10. The device of claim 1, wherein the one or more actuators are configured to generate membrane displacement in either of two opposing directions along a membrane normal with respect to an initial membrane position.

11. The device of claim 1, wherein the membrane has at least two sections of different stiffness.

12. The device of claim 11, wherein the membrane has at least two sections of different thickness.

13. The device of claim 1, wherein the membrane comprises a serpentine spring.

14. The device of claim 1, further comprising a segmented plate attached to the membrane, wherein, when the membrane is deformed, at least one segment of the plate changes orientation.

15. The device of claim 14, wherein the segmented plate has a reflective surface.

16. The device of claim 14, wherein the membrane and the segmented plate are manufactured from a single layer of material.

17. The device of claim 14, wherein the membrane comprises two serpentine springs connected at opposite sides of the segmented plate.

18. The device of claim 1, wherein the device is part of a dispersion compensator.

21. The device of claim 1, wherein:

the deformable membrane has a side that determines thickness of the membrane; and

the torsional member is attached to said side.

22. The device of claim 1, wherein said rotation causes:

a first portion of the torsional member to apply a first force to a part of the membrane that is in contact with the first portion; and

a second portion of the torsional member to apply a second force to a part of the membrane that is in contact with the second portion, wherein the first and second forces have different directions.

23. The device of claim 1, wherein said rotation tends to twist the membrane about the longitudinal axis.

19. A method of deforming a membrane in a MEMS device, comprising:

applying torque to the membrane using an actuator configured to change the shape of the membrane, wherein;

the membrane is movably connected to a support structure; and

one or more actuators are configured between the membrane and the support structure, each actuator adapted to apply torque to the membrane, wherein at least one of the one or more actuators is adapted to rotate a torsional member attached to the membrane about a longitudinal axis of said torsional member, said rotation causing the torsional member to apply torque to the membrane.

20. A MEMS device, comprising:

a deformable membrane movably connected to a support structure; and

means for applying torque to the membrane to change the shape of the membrane, said means configured between the membrane and the support structure, wherein the means for applying torque are adapted to rotate a torsional member attached to the membrane about a longitudinal axis of said torsional member, said rotation causing the torsional member to apply torque to the membrane.

24. A MEMS device, comprising:

a deformable membrane movably connected to a support structure; and

one or more actuators configured between the membrane and the support structure, each actuator adapted to apply torque to the membrane to change the shape of the membrane, wherein;

the one or more actuators comprise four actuators grouped into two actuator pairs located at opposite sides of the membrane; and

each actuator pair has actuators located at a single side of the membrane.

25. A MEMS device, comprising:

a deformable membrane movably connected to a support structure; and

one or more actuators configured between the membrane and the support structure, each actuator adapted to apply torque to the membrane to change the shape of the membrane, wherein;

the one or more actuators include a first actuator, comprising a movable portion rotatably connected between the support structure and a first side of the membrane, wherein rotation of the movable portion generates torque for the first side of the membrane;

the first actuator further comprises first and second electrodes fixedly attached to the support structure, wherein;

when a first voltage differential is applied between the movable portion and the first electrode, the movable portion rotates in a first direction; and

when a second voltage differential is applied between the movable portion and the second electrode, the movable portion rotates in a direction opposite to the first direction; and

the first actuator is a comb drive actuator.

26. A MEMS device, comprising:

a deformable membrane movably connected to a support structure; and

one or more actuators configured between the membrane and the support structure, each actuator adapted to apply torque to the membrane to change the shape of the membrane, wherein the one or more actuators include a first actuator, comprising a movable portion rotatably connected between the support structure and a first side of the membrane, wherein;

rotation of the movable portion generates torque for the first side of the membrane; and

the movable portion is supported by first and second members, the first member connected between the movable portion and the support structure and the second member connected between the movable portion and the first side of the membrane, the first and second members defining an axis of rotation for the movable portion.

27. A MEMS device, comprising:

a deformable membrane movably connected to a support structure;

one or more actuators configured between the membrane and the support structure, each actuator adapted to apply torque to the membrane to change the shape of the membrane; and

a segmented plate attached to the membrane, wherein, when the membrane is deformed, at least one segment of the plate changes orientation, wherein the membrane comprises two serpentine springs connected at opposite sides of the segmented plate.