Driver and method of operating a micro-electromechanical system device

• US 20020093722A1
• Filed: 12/01/2000
• Published: 07/18/2002
• Est. Priority Date: 12/01/2000
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Chan, Edward, Gasparyan, Arman
• Granted Patent: US 6,504,641 B2
• Time in Patent Office: Days
• US Class Current: 359/295
• CPC Class Codes: G02B 26/0841 the reflecting element being moved or deformed by electrostatic means
• CPC Class Codes: Y10S 359/904 Micromirror

Abstract

A driver for use with a micro-electromechanical system (MEMS) device, method of operation thereof and a MEMS device employing the driver and method. In one embodiment, the driver includes an actuation subsystem that provides an actuation voltage to alter an angle of an optical element of the MEMS device. The driver also includes a bias subsystem, coupled to the actuation subsystem, that applies a bias voltage between the optical element and the actuation subsystem, thereby reducing the actuation voltage.

Claims

1. A driver for use with a micro-electromechanical system (MEMS) device, comprising:

an actuation subsystem configured to provide an actuation voltage to alter an angle of an optical element of said MEMS device; and

a bias subsystem coupled to said actuation subsystem and configured to apply a bias voltage between said optical element and said actuation subsystem thereby reducing said actuation voltage.

2. The driver as recited in claim 1 wherein said bias voltage is a common-mode DC bias voltage.

3. The driver as recited in claim 1 wherein said bias voltage reduces said actuation voltage by more than about 75%.

4. The driver as recited in claim 1 wherein said actuation subsystem comprises a plurality of electrodes in electrical communication with a surface of said optical element.

5. The driver as recited in claim 1 wherein said actuation subsystem comprises a plurality of electrodes in electrical communication with an object coupled to said optical element.

6. The driver as recited in claim 1 wherein said MEMS device comprises a fulcrum and said actuation subsystem is configured to apply said actuation voltage to cause said optical element to rotate about said fulcrum.

7. The driver as recited in claim 1 wherein said MEMS device includes a spring and said bias voltage causes an electrostatic spring softening of said spring, thereby reducing said actuation voltage.

8. The driver as recited in claim 1 wherein said bias voltage is less than about 130% of a critical voltage of said MEMS device.

9. A method of operating a micro-electromechanical system (MEMS) device, comprising:

providing an actuation voltage to alter an angle of an optical element of said MEMS device; and

applying a bias voltage between said optical element and said actuation subsystem thereby reducing said actuation voltage.

10. The method as recited in claim 9 wherein said applying said bias voltage comprises applying a common-mode DC bias voltage.

11. The method as recited in claim 9 wherein said applying said bias voltage reduces said actuation voltage by more than about 75%.

12. The method as recited in claim 9 wherein said providing said actuation voltage comprises providing said actuation voltage to a plurality of electrodes in electrical communication with a surface of said optical element.

13. The method as recited in claim 9 wherein said providing said actuation voltage comprises providing said actuation voltage to a plurality of electrodes in electrical communication with an object coupled to said optical element.

14. The method as recited in claim 9 wherein said providing said actuation voltage causes said optical element to rotate about a fulcrum of said MEMS device.

15. The method as recited in claim 9 wherein said MEMS device includes a spring and said bias voltage causes an electrostatic spring softening of said spring, thereby reducing said actuation voltage.

16. The method as recited in claim 9 wherein said bias voltage is less than about 130% of a critical voltage of said MEMS device.

17. The method as recited in claim 9 wherein said applying said bias voltage comprises applying a positive potential bias voltage to a surface of said optical element.

18. The method as recited in claim 9 wherein said applying said bias voltage comprises applying a negative potential bias voltage to an actuation system.

19. The method as recited in claim 9 further comprising increasing a gap spacing between said optical element and an electrode to compensate for a decrease in tiltable range.

20. The method as recited in claim 19 further comprising decreasing a size of said electrode to compensate for said decrease in said tiltable range.

21. A micro-electromechanical system (MEMS) device, comprising:

an optical element having a light reflective optical layer located over a substrate;

a mounting substrate on which said optical element is rotatably mounted, said mounting substrate having a plurality of electrodes spaced adjacent thereto; and

a driver, couplable to said optical element, including;

an actuation subsystem that provides an actuation voltage to alter an angle of said optical element, and

a bias subsystem, coupled to said actuation subsystem, that applies a bias voltage between a surface of said optical element and said actuation subsystem thereby reducing said actuation voltage.

22. The MEMS device as recited in claim 21 wherein said bias voltage is a common-mode DC bias voltage.

23. The MEMS device as recited in claim 21 wherein said bias voltage reduces said actuation voltage by more than about 75%.

24. The MEMS device as recited in claim 21 wherein said plurality of electrodes are in electrical communication with a surface of said optical element.

25. The MEMS device as recited in claim 21 wherein said plurality of electrodes are in electrical communication with an object coupled to said optical element.

26. The MEMS device as recited in claim 21 wherein said plurality of electrodes comprise a four quadrant electrode structure.

27. The MEMS device as recited in claim 21 wherein said plurality of electrodes comprise a mirror-and-gimbal electrode structure.

28. The MEMS device as recited in claim 21 wherein said mounting substrate comprises a fulcrum and said actuation subsystem applies said actuation voltage to cause said optical element to rotate about said fulcrum.

29. The MEMS device as recited in claim 21 wherein said MEMS device includes a spring and said bias voltage causes an electrostatic spring softening of said spring, thereby reducing said actuation voltage.

30. The MEMS device as recited in claim 21 wherein a spacing between said plurality of electrodes and said mounting substrate may be increased or decreased to provide more or less rotation.