Device and method for wavelength filtering

• US 7,898,521 B2
• Filed: 08/26/2005
• Issued: 03/01/2011
• Est. Priority Date: 09/27/2004
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Gally, Brian J., Cummings, William J.
• Primary Examiner(s): Wang; Quan-Zhen
• Assistant Examiner(s): Sheng; Tom V
• Application Number:
  US11/213,659
• Publication Number:
  US 20060067633A1
• Time in Patent Office: 2,013 Days
• Field of Search: 345/84, 345/85, 345/108, 385129-132, 359/247, 359/254, 359/259, 359/260, 359/261, 359/263, 359/577, 359/578
• US Class Current: 345/108
• 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 6/29356 Interference cavity within a single light guide, e.g. between two fibre gratings G02B6/29347 - G02B6/2935 take precedence; evanescent coupling to a resonator cavity G02B6/29335
• CPC Class Codes: G09G 3/3466 based on interferometric effect
• CPC Class Codes: Y10T 29/49002 Electrical device making

Abstract

Embodiments include devices and methods for wavelength filtering. For example, one embodiment includes a display comprising a plurality of the display elements each comprising a movable reflector, a first partial reflector, and a second partial reflector. The first partial reflector is positioned at a first distance from the movable reflector and forms a first optical resonant cavity therebetween. The second partial reflector is positioned at a second distance from said first partial reflector and forming a second optical resonant cavity therebetween. In various embodiments, the movable reflector is movable with respect to the first partial reflector to alter the first optical cavity. Other embodiments include a method of making devices.

Claims

1. A device for modulating light, the device comprising:

a movable reflector;

a first partial reflector positioned at a first distance from said movable reflector;

at least one layer of dielectric material between said first partial reflector and said movable reflector; and

a second partial reflector positioned at a second fixed distance from said first partial reflector,

wherein said movable reflector is movable with respect to said first partial reflector to alter said first distance and wherein said first and second partial reflectors comprise an interferometric filter configured to increase the saturation of light reflected by said movable reflector and said first partial reflector.

2. The device of claim 1, further comprising an electrode between said first and second partial reflectors.

3. The device of claim 2, further comprising a layer of dielectric material between said electrode and said second partial reflector.

4. The device of claim 1, wherein said first partial reflector is positioned between said movable reflector and said second partial reflector.

5. The device of claim 1, further comprising a substrate, wherein said second partial reflector is between said first partial reflector and said substrate.

6. The device of claim 1, wherein said first and second partial reflectors define an optical cavity that is configured to selectively transmit visible wavelengths associated with a color of light and substantially filter other visible wavelengths when illuminated with white light.

7. The device of claim 1, further comprising at least one layer of dielectric material between said first partial reflector and said second partial reflector.

8. The device of claim 1, wherein said movable reflector and said first partial reflector reflect white light when the movable reflector is in at least one position.

9. The device of claim 1, wherein said device forms part of a display.

10. The device of claim 9, further comprising:

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

a memory device in electrical communication with said processor.

11. The device of claim 10, further comprising:

a driver circuit configured to send at least one signal to said display.

12. The device of claim 11, further comprising:

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

13. The device of claim 12, further comprising:

an image source module configured to send said image data to said processor.

14. The device of claim 13, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

15. The device of claim 10, further comprising:

an input device configured to receive input data and to communicate said input data to said processor.

16. The device of claim 1, wherein said movable reflector and said second partial reflector define an optical cavity configured to contribute insubstantially to the visible light spectral response of said movable reflector and said first partial reflector.

17. The device of claim 1, wherein the interferometric filter comprises a color filter.

18. The device of claim 1, wherein the interferometric filter is configured to provide a band pass response characterized by a particular color, whereby the interferometric filter selectively transmits visible wavelengths associated with said particular color and substantially filters other visible wavelengths.

19. The device of claim 1 provided with electronics configured to drive the movable reflector such that light reflected by said movable reflector and said first partial reflector can be modulated so as to form part of an image viewable on a display.

20. The device of claim 19, wherein the display comprises a reflective display.

21. The device of claim 1, wherein the display is configured to form an image by selectively modulating ambient light.

22. The device of claim 1, wherein the movable reflector comprises a metal.

23. The device of claim 1, wherein at least one of the first and second partial reflectors comprises a metal.

24. The device of claim 1, wherein said device comprises a display element included in an array of display elements of a display such that light reflected by said movable reflector and said first partial reflector forms part of an image produced by said array of display elements and said interferometric filter increases the color gamut of said display.

25. A display comprising a plurality of display elements, each of the display elements comprising:

means for reflecting light, said reflecting means being movable;

first means for partially reflecting light, wherein said movable reflecting means and said first partially reflecting means are configured to interferometrically modulate light;

at least one layer of dielectric material between said first partially reflecting means and said movable reflecting means; and

second means for partially reflecting light, wherein said first partially reflecting means and said second partially reflecting means are configured to interferometrically filter light, and wherein said first and second partially reflecting means comprise an interferometric filter configured to increase the saturation of light reflected by said movable reflecting means and said first partially reflecting means.

26. The display of claim 25, further comprising:

means for actuating said means for reflecting light.

27. The display of claim 26, wherein said means for actuating comprises an electrode.

28. The display of claim 25, wherein said reflecting means comprises a reflective layer.

29. The display of claim 25, wherein said first partially reflecting means comprises a partially reflective layer.

30. The display of claim 25, wherein said second partially reflecting means comprises a partially reflective layer.

31. The display of claim 25, wherein said interferometric filter comprises a color filter.

32. The display of claim 25 provided with means for controlling, wherein said controlling means are configured to drive said movable reflecting light means such that light reflected by said movable reflecting light means and said first partially reflecting light means can be modulated so as to form part of an image viewable on the display.

33. The display of claim 32, wherein the display comprises a reflective display.

34. The display of claim 25, wherein light reflected by said movable reflecting light means and said first partially reflecting light means forms part of an image produced by said plurality of display elements and said interferometric filter increases the color gamut of said display.

35. A device for modulating light, the device comprising:

a movable reflector;

a first partial reflector positioned at a first distance from said movable reflector, the movable reflector being movable with respect to said partial reflector to alter said first distance;

at least one layer of dielectric material between said first partial reflector and said movable reflector;

a second partial reflector positioned at a second fixed distance from said first partial reflector; and

an electrode positioned between said first and second partial reflectors and configured to alter the position of said movable mirror,

wherein said first and second partial reflectors comprise an interferometric filter configured to increase the saturation of light reflected by said movable reflector and said first partial reflector.

36. The device of claim 35, further comprising a layer of dielectric material between said electrode and said second partial reflector.

37. The device of claim 35, further comprising a substrate, wherein said second partial reflector is between said first reflector and said substrate.

38. The device of claim 35, further comprising at least one layer of dielectric material between said first partial reflector and said second partial reflector.

39. The device of claim 35, wherein the interferometric filter comprises a color filter.

40. The device of claim 35 provided with electronics configured to drive the movable reflector such that light reflected by said movable reflector and said first partial reflector can be modulated so as to form part of an image viewable on a display.

41. The device of claim 35, wherein the display comprises a reflective display.

42. The device of claim 35, wherein said device comprises a display element included in an array of display elements of a display such that light reflected by said movable reflector and said first partial reflector forms part of an image produced by said array of display elements and said interferometric filter increases the color gamut of said display.

43. A method of making a device for modulating light, the method comprising:

forming a movable reflector;

forming a first partial reflector positioned at a first distance from said movable reflector;

forming at least one layer of dielectric material between said first partial reflector and said movable reflector; and

forming a second partial reflector positioned at a second fixed distance from said first partial reflector,

wherein said movable reflector is movable with respect to said first partial reflector to alter said first distance and wherein said first and second partial reflectors comprise an interferometric filter configured to increase the saturation of light reflected by said movable reflector and said first partial reflector.

44. The method of claim 43, further comprising forming an electrode between said first and second partial reflectors.

45. The method of claim 44, further comprising forming a layer of dielectric material between said electrode and said second partial reflector.

46. The method of claim 43, further comprising performing said steps of forming onto a substrate, wherein said second partial reflector is between said first reflector and said substrate.

47. The method of claim 43, wherein said first and second partial reflectors are formed to define an optical cavity that is configured to selectively transmit visible wavelengths associated with a color of light and substantially filter other visible wavelengths when illuminated with white light.

48. The method of claim 43, further comprising forming at least one layer of dielectric material between said first partial reflector and said second partial reflector.

49. The method of claim 43, wherein said movable reflector and said first partial reflector are formed so as to reflect white light when the movable reflector is in at least one position.

50. The device formed by the method of claim 43.

51. The method of claim 43, wherein said movable reflector and said second partial reflector define an optical cavity configured to contribute insubstantially to the visible light spectral response of said movable reflector and said first partial reflector.

52. The method of claim 43, wherein the interferometric filter comprises a color filter.

53. The method of claim 43 further comprising providing electronics configured to drive the movable reflector such that light reflected by said movable reflector and said first partial reflector can be modulated so as to form part of an image viewable on a display.

54. The method of claim 53, wherein the display comprises a reflective display.

55. The method of claim 43, wherein said device comprises a display element included in an array of display elements of a display such that light reflected by said movable reflector and said first partial reflector forms part of an image produced by said array of display elements and said interferometric filter increases the color gamut of said display.