MICROELECTROMECHANICAL DEVICE WITH OPTICAL FUNCTION SEPARATED FROM MECHANICAL AND ELECTRICAL FUNCTION

• US 20080013144A1
• Filed: 07/02/2007
• Published: 01/17/2008
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Chui, Clarence, Kogut, Lior, Chiang, Chih-Wei, Tung, Ming-Hau, Tung, Yeh-Jiun, Endisch, Denis
• Granted Patent: US 7,612,932 B2
• Time in Patent Office: Days
• US Class Current: 359/224
• CPC Class Codes: B81B 2201/042 Micromirrors, not used as optical switches
• CPC Class Codes: B81B 3/0086 Electrical characteristics, e.g. reducing driving voltage, improving resistance to peak voltage
• CPC Class Codes: G02B 26/001 based on interference in an adjustable optical cavity interference filters G02B5/28; devices or arrangements using multiple reflections in spectrometry or monochromators G01J3/26
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

A microelectromechanical (MEMS) device includes a first reflective layer, a movable element, and an actuation electrode. The movable element is over the first reflective layer. The movable element includes a deformable layer and a reflective element. The actuation electrode is between the deformable layer and the reflective element.

Claims

1. A microelectromechanical (MEMS) device comprising:

a first reflective layer;

a movable element over the first reflective layer, the movable element comprising a deformable layer and a reflective element; and

an actuation electrode between the deformable layer and the reflective element.

2. The MEMS device of claim 1, wherein a voltage applied to the actuation electrode generates a first attractive force in a first direction on a first portion of the movable element and generates a second attractive force in a second direction on a second portion of the movable element, the second direction substantially opposite the first direction, the first attractive force greater than the second attractive force, the movable element responsive to the first and second attractive forces by moving generally in the first direction.

3. The MEMS device of claim 2, wherein the first portion of the movable element comprises the deformable layer.

4. The MEMS device of claim 2, wherein the first portion of the movable element comprises the reflective element.

5. The MEMS device of claim 2, wherein a distance between the actuation electrode and the second portion of the movable element is greater than a distance between the actuation electrode and the first portion of the movable element.

6. The MEMS device of claim 2, wherein a distance between the actuation electrode and the second portion of the movable element is at least about 10% greater than a distance between the actuation electrode and the first portion of the movable element.

7. The MEMS device of claim 2, further comprising a conductive layer between the actuation electrode and the second portion.

8. The MEMS device of claim 1, further comprising a second actuation electrode.

9. The MEMS device of claim 8, wherein the movable element is responsive to voltages applied to the actuation electrode between the deformable layer and the reflective element by moving generally in a first direction and wherein the movable element is responsive to voltages applied to the second actuation electrode by moving generally in a second direction, the second direction substantially opposite the first direction.

10. The MEMS device of claim 1, wherein the first reflective layer is spaced from the reflective element when an actuation voltage is applied to the actuation electrode.

11. The MEMS device of claim 1, wherein a lower surface of the deformable layer contacts a stationary portion of the device when an actuation voltage is applied to the actuation electrode.

12. The MEMS device of claim 1, wherein an upper surface of the reflective element contacts a stationary portion of the device when an actuation voltage is applied to the actuation electrode.

13. The MEMS device of claim 1, further comprising:

a display;

a processor that is configured to communicate with said display, said processor being configured to process image data; and

a memory device that is configured to communicate with said processor.

14. The MEMS device of claim 13, further comprising a driver circuit configured to send at least one signal to the display.

15. The MEMS device of claim 14, further comprising a controller configured to send at least a portion of the image data to the driver circuit.

16. The MEMS device of claim 13, further comprising an image source module configured to send said image data to said processor.

17. The MEMS device of claim 16, wherein the image source module comprises at least one of a receiver, transceiver, and transmitter.

18. The MEMS device of claim 13, further comprising an input device configured to receive input data and to communicate said input data to said processor.

19. A microelectromechanical (MEMS) device comprising:

means for moving a portion of the device, the moving means comprising means for deforming and first means for reflecting light;

second means for reflecting light; and

means for actuating the moving means, the actuating means between the deforming means and the first reflecting means.

20. The MEMS device of claim 19, wherein the second reflecting means comprises a reflective layer.

21. The MEMS device of claim 19, wherein the moving means comprises a movable element.

22. The MEMS device of claim 19, wherein the deforming means comprises a deformable layer.

23. The MEMS device of claim 19, wherein the first reflective means comprises a reflective element.

24. The MEMS device of claim 19, wherein the actuating means comprises an actuation electrode.

25. A method of manufacturing a microelectromechanical (MEMS) device, the method comprising:

forming a first sacrificial layer over a reflective layer;

forming a reflective element over the first sacrificial layer;

forming a second sacrificial layer over the reflective element;

forming an actuation electrode over the second sacrificial layer;

forming a third sacrificial layer over the actuation electrode;

forming a deformable layer over the third sacrificial layer, the deformable layer mechanically coupled to the reflective element; and

removing the first, second, and third sacrificial layers.

26. The method of claim 25, wherein the second sacrificial layer is thicker than the third sacrificial layer.

27. The method of claim 25, wherein the third sacrificial layer is thicker than the second sacrificial layer.

28. The method of claim 25, further comprising forming a conductive layer between the reflective element and the actuation electrode.

29. The method of claim 25, further comprising forming a second actuation electrode over the reflective layer before forming the first sacrificial layer.

30. The method of claim 25, further comprising:

forming a fourth sacrificial layer above the deformable layer;

forming second actuation electrode over the fourth sacrificial layer; and

removing the fourth sacrificial layer.

31. A MEMS device fabricated by the method of claim 25.

32. A method of modulating light, the method comprising:

providing a display element comprising a reflective layer, a movable element over the reflective layer, and an actuation electrode, the movable element comprising a deformable layer and a reflective element, the actuation electrode between the deformable layer and the reflective element; and

applying a voltage to the actuation electrode, the voltage generating a first attractive force in a first direction on a first portion of the movable element and generating a second attractive force in a second direction on a second portion of the movable element, the second direction substantially opposite to the first direction, the first attractive force greater than the second attractive force, thereby causing the movable element to move generally in the first direction.

33. The method of claim 32, wherein the first portion of the movable element comprises the deformable layer.

34. The method of claim 32, wherein the first portion of the movable element comprises the reflective element.