Apparatus and method for reducing perceived color shift

• US 20060077122A1
• Filed: 03/11/2005
• Published: 04/13/2006
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Gally, Brian J., Kothari, Manish
• Granted Patent: US 7,928,928 B2
• Time in Patent Office: Days
• US Class Current: 345/32
• 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 5/20 Filters polarising elements G02B5/30

Abstract

An apparatus and method for reducing perceived color shift as a function of viewing angle is disclosed. One embodiment is a display device that includes a color light modulator and a color filter. The filter is configured to filter wavelengths of light that would be perceived as color shifted light when reflected by the modulator at an off-axis viewing angle. Another embodiment includes a color light modulator and a color light source configured to provide light having a spectral content that lacks the wavelengths that would be perceived as color shifted light by a view of the display at an off-axis viewing angle. Another embodiment are methods of making such display devices.

Claims

1. A display device comprising:

at least one light-modulating element configured to output colored light, said light-modulating element comprising first and second reflective surfaces, said second surface being movable with respect to said first surface; and

a filter comprising a layer of material that selectively transmits certain visible wavelengths and substantially filters other visible wavelengths when illuminated with white light, said filter positioned to filter light modulated by said light-modulating element.

2. The display device of claim 1, wherein said filter is positioned to filter incident light modulated by said light modulating element.

3. The display device of claim 1, wherein said filter is positioned to filter light output by said light modulating element.

4. The display device of claim 3, wherein said filter is positioned to filter incident light modulated by said light modulating element.

5. The display device of claim 1, wherein said filter has at least one red, green or blue transmission peak that selectively transmits at least one of red, green, or blue light.

6. The display device of claim 1, wherein said light selectively transmitted by said filter has a color substantially corresponding to said output colored light of said interferometric modulator.

7. The display device of claim 1, wherein said light selectively transmitted by said filter comprises at least red and green light, red and blue light, or green and blue light.

8. The display device of claim 1, wherein said light selectively transmitted by said filter comprises at least red, green, and blue light.

9. The display device of claim 1, wherein said light modulating element comprises an interferometric modulator element.

10. The display device of claim 1, further comprising a transmissive substrate positioned between said first reflective surface and said filter.

11. The display device of claim 1, wherein said material comprises a light absorbing material.

12. The display device of claim 11, wherein said material comprises dyed material.

13. The display device of claim 12, wherein said dyed material comprises dyed photoresist.

14. The display device of claim 1, wherein said filter forms part of a filter array comprising different filter elements configured to transmit at least two different colors respectively.

15. The display device of claim 14, wherein said filter array comprises red, green, and blue color filter elements.

16. A method of fabricating a display, comprising:

forming a light-modulating element configured to output colored light, said color light-modulating element comprising first and second reflective surfaces that form a cavity, said second surface being movable with respect to said first surface; and

positioning a filter comprising a layer of material with respect to said light-modulating element such that said filter filters light modulated by said light-modulating element, said layer of material selectively transmitting certain visible wavelengths and substantially filters other visible wavelengths when illuminated with white light.

17. The method of claim 16, wherein positioning said filter comprises positioning said filter to filter incident light modulated by said light modulating element.

18. The method of claim 16, wherein positioning said filter comprises positioning said filter to filter light output by said light modulating element.

19. The method of claim 18, wherein positioning said filter comprises positioning said filter to filter incident light modulated by said light modulating element.

20. The method of claim 16, wherein said step of fabricating a light-modulating element comprises providing an interferometric modulator element.

21. The method of claim 16, wherein said light selectively transmitted by said filter comprises at least one of red, green, or blue light.

22. The method of claim 16, wherein said light selectively transmitted by said filter comprises a color substantially corresponding to said output colored light of said interferometric modulator.

23. The method of claim 16, wherein said light selectively transmitted by said filter includes at least two colors selected from the group comprising red, green, and blue color light.

24. The method of claim 16, wherein forming said light-modulating element comprises forming an interferometric modulator element.

25. The method of claim 16, wherein forming said light-modulating element comprises forming said light-modulating element on a transmissive substrate positioned between said first reflective surface and said filter.

26. The method of claim 16, wherein said material comprises a light absorbing material.

27. The method of claim 26, wherein said material comprises dyed material.

28. The method of claim 27, wherein said dyed material comprises dyed photoresist.

29. The method of claim 16, wherein positioning said filter comprises positioning a filter array comprising at least two different filter elements configured to transmit at least two different colors respectively.

30. The method of claim 29, wherein said filter array comprises red, green, and blue color filter elements.

31. The method of claim 16, wherein said filter outputs colored light when illuminated with white light.

32. A display region formed by said method of claim 16.

33. A display system comprising:

a light-modulating element configured to output light having at least one spectral peak within the visible spectrum, said light-modulating element comprising first and second reflective surfaces, said second surface being movable with respect to said first surface; and

a light emitter that outputs visible light having at least one spectral peak within the visible spectrum, said light emitter configured to illuminate said first and second reflective surfaces of said light-modulating element.

34. The display device of claim 33, wherein said light emitter comprises a color light emitter that outputs colored light.

35. The display device of claim 33, wherein said spectral peak of said light emitter substantially overlaps a spectral peak of said light-modulating element.

36. The display device of claim 34, wherein said colored light provided by said light emitter comprises at least one of red, green, or blue light.

37. The display device of claim 33, wherein said light provided by said light emitter comprises colored light substantially corresponding to said colored light output by said light-modulating element.

38. The display device of claim 33, wherein said light provided by said light emitter comprises at least red and green, red and blue, or green and blue light.

39. The display device of claim 33, wherein said light provided by said light emitter comprises at least red, green, and blue.

40. The display device of claim 33, wherein said light modulating element comprises an interferometric modulator element.

41. The display device of claim 33, further comprising a plurality of light emitters.

42. The display device of claim 41, wherein said light emitters comprises red, green, and blue color light emitters.

43. The display device of claim 42, wherein said red, green, and blue light emitters produce light at a range of wavelengths that are respectively centered at about 450, 550, and 650 nm.

44. A method of fabricating a display device comprising:

providing a light-modulating element configured to output light having at least one spectral peak within the visible spectrum, said light-modulating element comprising first and second reflective surfaces, said second surface being movable with respect to said first surface; and

positioning a light emitter with respect to said light-modulating element to illuminate said first and second reflective surfaces of said light-modulating element, said light emitter outputting visible light having at least one spectral peak within the visible spectrum.

45. A display device fabricated by the method of claim 44.

46. A display device comprising:

a plurality of light-modulating elements configured to output colored light, said light-modulating elements comprising first and second reflective surfaces, said second surface being movable with respect to said first surface; and

a filter array comprising a plurality of filter elements that selectively transmit certain visible wavelengths and substantially filters other visible wavelengths when illuminated with white light, at least two of said filter elements having different transmission spectrums, said filter array positioned to filter light modulated by said light-modulating elements.

47. A method of fabricating a display, comprising:

forming a plurality of light-modulating elements configured to output colored. light, said color light-modulating elements comprising first and second reflective surfaces that form a cavity, said second surface being movable with respect to said first surface; and

positioning a filter array comprising a plurality of filter elements with respect to said light-modulating elements such that said filter array filters light modulated by said plurality of light-modulating elements, at least two of said filter elements having different transmission spectrums.

48. A display device comprising:

means for interferometrically modulating incident light so as to output colored light; and

means for selectively transmitting certain visible wavelengths and substantially filtering other visible wavelengths when illuminated with white light, wherein said means for selectively transmitting reduces perceived color shift of said output colored light.

49. A method of fabricating a display, comprising:

means for interferometrically modulating incident light so as to output light having at least one spectral peak within the visible spectrum; and

means for illuminating said means for interferometrically modulating with visible light having at least one spectral peak within the visible spectrum.