Electromechanical device with optical function separated from mechanical and electrical function

• US 9,001,412 B2
• Filed: 10/10/2012
• Issued: 04/07/2015
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Chui, Clarence, Cummings, William, Gally, Brian James, Kogut, Lior, Tung, Ming-Hau, Tung, Yeh-Jiun, Chiang, Chih-Wei, Endisch, Denis
• Primary Examiner(s): Lester, Evelyn A
• Application Number:
  US13/648,750
• Publication Number:
  US 20130069958A1
• Time in Patent Office: 909 Days
• Field of Search: 359/223.1, 359/224.1, 359290-292, 359/295, 359/298, 359/318, 359/224.2, 348/770, 348/771, 345/85, 345/108
• US Class Current: 359/290
• CPC Class Codes: B81B 2201/047 Optical MEMS not provided for in B81B2201/042 - B81B2201/045
• CPC Class Codes: B81B 3/0051 For defining the movement, i.e. structures that guide or limit the movement of an element mechanical arrangements for preventing or damping vibration or shock H01H3/60
• 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: G02B 26/023 comprising movable attenuating elements, e.g. neutral density filters
• CPC Class Codes: G02B 26/08 for controlling the direction of light in light guides G02B6/35
• CPC Class Codes: G02F 1/0128 based on electro-mechanical, magneto-mechanical, elasto-optic effects
• CPC Class Codes: G02F 1/133621 providing coloured light G02F1/133617, G02F1/133533 take precedence
• CPC Class Codes: G02F 1/29 for the control of the position or the direction of light beams, i.e. deflection
• CPC Class Codes: G09G 3/3466 based on interferometric effect
• CPC Class Codes: G09G 3/3696 Generation of voltages supplied to electrode drivers
• CPC Class Codes: Y10T 29/42 Piezoelectric device making

Abstract

A microelectromechanical (MEMS) device includes a substrate, a movable element over the substrate, and an actuation electrode above the movable element. The movable element includes a deformable layer and a reflective element. The deformable layer is spaced from the reflective element.

Claims

1. An electromechanical device comprising:

a substrate;

an actuation electrode; and

a movable element between the substrate and the actuation electrode, the movable element including a deformable layer and a reflective element each being between the substrate and the actuation electrode, the deformable layer spaced from the reflective element along a direction generally perpendicular to the reflective element, wherein the movable element is configured to be selectively switched among at least a first state having a first spectral reflectance being a first color, a second state having a second spectral reflectance being a second color, and a third state having a third spectral reflectance being a black state,

wherein the first state includes the reflective element in a relaxed position, wherein the second state includes the reflective element in a first actuated position, and wherein the third state includes the reflective element in a second actuated position,

wherein the reflective element is movable to the second actuated position upon application of a voltage difference between the reflective element and a second actuation electrode, and

wherein the reflective element is movable to at least one of the first actuated position and the second actuated position upon application of voltage potential differences both between the reflective element and the actuation electrode and between the reflective element and the second actuation electrode.

2. The device of claim 1, wherein a top surface of the substrate is spaced from the reflective element when no voltage is applied to the actuation electrode.

3. The device of claim 1, further comprising a support structure between the substrate and the deformable layer, the support structure configured to support the deformable layer.

4. The device of claim 1, comprising a stationary element configured to be a stop for movement of the movable element.

5. The device of claim 4, further comprising a roughened surface between the stationary element and the movable element.

6. The device of claim 4, further comprising an anti-stiction layer between the stationary element and the movable element.

7. The device of claim 4, wherein the stationary element includes an insulating layer between the deformable layer and the actuation electrode.

8. The device of claim 1, wherein an interference display element includes the device.

9. The device of claim 1, wherein the first color is substantially yellow and the second color is substantially blue, or wherein the first color is substantially yellow and the second color is substantially cyan.

10. The device of claim 1, wherein the first color has an order and the second color has a same or higher order.

11. The device of claim 1, wherein the reflective element is movable to the first actuated position upon application of a voltage difference between the reflective element and the actuation electrode.

12. The device of claim 1, further comprising:

a display;

a processor configured to communicate with the display, the processor configured to process image data; and

a memory device configured to communicate with the processor.

13. The device of claim 12, further comprising:

a driver circuit configured to send at least one signal to the display; and

a controller configured to send at least a portion of the image data to the driver circuit.

14. The device of claim 12, further comprising an image source module configured to send the image data to the processor;

wherein the image source module includes at least one of a receiver, a transceiver, and a transmitter.

15. The device of claim 12, further comprising an input device configured to receive input data and to communicate the input data to the processor.

16. The device of claim 1, wherein the substrate includes an optical stack.

17. The device of claim 16, wherein light incident on the reflective element is reflected from the reflective element, the incident light and the reflected light propagating through the optical stack and not propagating through the actuation electrode.

18. The device of claim 1, wherein the actuation electrode includes a non-transparent conductor.

19. The device of claim 18, wherein the non-transparent conductor includes at least one of aluminum (Al), copper (Cu), silver (Ag), and gold (Au).

20. The device of claim 1, wherein the substrate includes the second actuation electrode.

21. The device of claim 1, wherein the second actuation electrode is between the deformable layer and the reflective element.

22. An electromechanical device comprising:

means for moving a portion of the device, the moving means including means for deforming and means for reflecting, the deforming means spaced from the reflecting means along a direction generally perpendicular to the reflecting means;

means for supporting the moving means; and

means for actuating the moving means, the moving means including both the deforming means and the reflecting means each being between the supporting means and the actuating means, wherein the moving means is configured to be selectively switched among at least a first state having a first spectral reflectance being a first color, a second state having a second spectral reflectance being a second color, and a third state having a third spectral reflectance being a black state,

wherein the first state includes the reflecting means in a relaxed position, wherein the second state includes the reflecting means in a first actuated position, and wherein the third state includes the reflecting means in a second actuated position,

wherein the reflecting means is movable to the second actuated position upon application of a voltage difference between the reflecting means and second means for actuating the moving means, and

wherein the reflecting means is movable to at least one of the first actuated position and the second actuated position upon application of voltage potential differences both between the reflecting means and the actuating means and between the reflecting means and the second actuating means.

23. The device of claim 22, wherein the supporting means includes a substrate, or wherein the moving means includes a movable element, or wherein the deforming means includes a deformable layer, or wherein the reflecting means includes a reflective element, or wherein the actuating means includes an actuation electrode.

24. The device of claim 22, comprising means for stopping movement of the moving means.

25. The device of claim 24, further comprising a roughened surface between the stopping means and the moving means.

26. The device of claim 24, further comprising an anti-stiction layer between the stopping means and the moving means.

27. The device of claim 24, wherein the stopping means includes an insulating layer between the deforming means and the actuating means.

28. The device of claim 22, wherein the first color is substantially yellow and the second color is substantially blue, or wherein the first color is substantially yellow and the second color is substantially cyan.

29. The device of claim 22, wherein the first color has an order and the second color has a same or higher order.

30. The device of claim 22, wherein the reflecting means is movable to the first actuated position upon application of a voltage difference between the reflecting means and the actuating means.

31. The device of claim 22, wherein the second actuating means includes a second actuation electrode.

32. The device of claim 22, wherein the supporting means includes the second actuating means.

33. The device of claim 22, wherein the second actuating means is between the deforming means and the reflecting means.

34. A method for modulating light, comprising:

providing a display element including a substrate, a movable element, and an actuation electrode, the movable element including a deformable layer and a reflective element each being between the substrate and the actuation electrode, the deformable layer spaced from the reflective element along a direction generally perpendicular to the reflective element;

applying a voltage to the actuation electrode, the voltage generating an attractive force on the movable element, thereby causing the movable element to move away from the substrate; and

selectively switching the movable element among at least a first state having a first spectral reflectance being a first color, a second state having a second spectral reflectance being a second color, and a third state having a third spectral reflectance being a black state,

wherein selectively switching the movable element among the first state includes switching the reflective element to a relaxed position, wherein selectively switching the movable element among at least the second state includes switching the reflective element to a first actuated position, and wherein selectively switching the movable element among at least the third state includes switching the reflective element to a second actuated position,

wherein switching the reflective element to the second actuated position includes applying a voltage difference between the reflective element and a second actuation electrode, and

wherein switching the reflective element to at least one of the first actuated position and the second actuated position includes applying voltage potential differences both between the reflective element and the actuation electrode and between the reflective element and the second actuation electrode.

35. The method of claim 34, wherein the display element includes a stationary element, and wherein the method further comprises contacting the stationary element and stopping movement of the movable element.

36. The method of claim 35, wherein contacting the stationary element includes touching the deformable layer to the stationary element.

37. The method of claim 35, wherein contacting the stationary element includes touching the reflective element to the stationary element.

38. The method of claim 34, wherein the first color is substantially yellow and the second color is substantially blue, or wherein the first color is substantially yellow and the second color is substantially cyan.

39. The method of claim 34, wherein the first color has an order and the second color has a same or higher order.

40. The method of claim 34, wherein switching the reflective element to the first actuated position includes applying a voltage difference between the reflective element and the actuation electrode.

41. The method of claim 34, wherein the substrate includes the second actuation electrode.

42. The method of claim 34, wherein the second actuation electrode is between the deformable layer and the reflective element.