Display apparatus with optical cavities

• US 7,876,489 B2
• Filed: 09/26/2006
• Issued: 01/25/2011
• Est. Priority Date: 06/05/2006
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Pixtronix, Incorporated (Qualcomm, Inc.)
• Inventors: Barton, Roger W., Hagood, Nesbitt W., Gandhi, Jignesh
• Primary Examiner(s): Thompson; Timothy J
• Application Number:
  US11/528,191
• Publication Number:
  US 20070279727A1
• Time in Patent Office: 1,582 Days
• Field of Search: 359/290, 359/291, 359/223, 359/224, 359/230, 359/233
• US Class Current: 359/242
• CPC Class Codes: G02B 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer

Abstract

A display includes an array of light modulators that define a display plane, a light guide and front- and rear-facing reflective surfaces. The light guide includes a plurality of geometric light redirectors, and at least 50% of the light guide'"'"'s rear surface is parallel to the display plane. The rear-facing reflective surface is parallel to the display plane and includes a plurality of apertures.

Claims

1. A display comprising:

an array of light modulators defining a display surface;

a light guide having front and rear surfaces and a plurality of geometric light redirectors formed therein;

a rear-facing reflective layer, positioned proximate to the display surface, wherein the rear-facing reflective surface has a plurality of apertures formed therein;

a front-facing reflective layer positioned proximate the rear surface of the light guide; and

a light injection system including a lamp and a light collimator for introducing a non-random fraction of light output by the lamp into the light guide as collimated light within a predetermined range of angles.

2. The display of claim 1, wherein the array of light modulators comprises a plurality of MEMs-based light modulators for selectively allowing light passing through the plurality of apertures in the rear-facing reflective layer to contribute to the formation of an image.

3. The display of claim 1, wherein at least 50% of the rear surface of the light guide is substantially parallel to the display surface.

4. The display of claim 1, wherein the rear-facing reflective layer comprises a dielectric mirror.

5. The display of claim 1, wherein the rear-facing reflective layer comprises a metal layer.

6. The display of claim 1, comprising a refractive layer, having a refractive index less than that of a refractive index of the light guide, disposed between the rear-facing reflective layer and the front surface of the light guide.

7. The display of claim 1, wherein the plurality of geometric light redirectors comprise substantially smooth reflective surfaces.

8. The display of claim 1, comprising a prismatic turning film positioned between the light guide and the rear-facing reflective layer.

9. The display of claim 1, comprising a brightness enhancement film positioned between the light guide and the rear-facing reflective layer.

10. The display of claim 1, comprising a side-facing reflective layer positioned proximate to a side of the light guide.

11. The display of claim 1, wherein the plurality of geometric light redirectors comprise prismatic light redirectors.

12. A display comprising:

an array of light modulators defining a display surface;

a light guide having front and rear surfaces and a plurality of geometric light redirectors formed therein;

a rear-facing reflective layer, positioned proximate to the display surface, wherein the rear-facing reflective surface has a plurality of apertures formed therein; and

a front-facing reflective layer positioned proximate the rear surface of the light guide, wherein at least 50% of light reflecting off of the rear-facing reflective layer within 40 degrees of an axis perpendicular to the display surface is redirected back towards the rear-facing reflective layer within 40 degrees of the axis.

13. The display of claim 12, wherein at least 50% of light reflecting off of the rear-facing reflective layer within 30 degrees of an axis perpendicular to the display surface is redirected back towards the rear-facing reflective layer within 30 degrees of the axis.

14. The display of claim 12, wherein at least 50% of light reflecting off of the rear-facing reflective layer within 20 degrees of an axis perpendicular to the display surface is redirected back towards the rear-facing reflective layer within 20 degrees of the axis.

15. The display of claim 12, wherein at least 70% of light reflecting off of the rear-facing reflective layer within 40 degrees of an axis perpendicular to the display surface is redirected back towards the rear-facing reflective layer within 40 degrees of the axis.

16. The display of claim 12, wherein at least 70% of light reflecting off of the rear-facing reflective layer within 30 degrees of an axis perpendicular to the display surface is redirected back towards the rear-facing reflective layer within 30 degrees of the axis.

17. The display of claim 12, wherein the array of light modulators has a light modulator pitch, and the distance between the rear-facing reflective surface and the display surface is less than the light modulator pitch.

18. The display of claim 12, wherein the array of light modulators is formed on a substrate, and the distance between the rear-facing reflective layer and the display surface is less than the thickness of the substrate.

19. The display of claim 12, wherein the array of light modulators comprises a plurality of MEMs-based light modulators for selectively allowing light passing through the plurality of apertures in the rear-facing reflective layer to contribute to the formation of an image.

20. The display of claim 12, wherein the rear-facing reflective layer comprises a dielectric mirror.

21. The display of claim 12, wherein the rear-facing reflective layer comprises a metal layer.

22. The display of claim 12, comprising a refractive layer, having a refractive index less than that of a refractive index of the light guide, disposed between the rear-facing reflective layer and the front surface of the light guide.

23. The display of claim 12, wherein the light guide comprises a composite of at least first and second layers.

24. The display of claim 23, wherein the first layer of the light guide comprises one of glass and plastic.

25. The display of claim 23, wherein the second layer of the light guide comprises one of glass and plastic.

26. The display of claim 12, wherein the plurality of geometric light redirectors comprise substantially smooth reflective surfaces.

27. The display of claim 12, wherein the rear-facing and front-facing reflective layers comprise specular reflective layers.

28. The display of claim 12, wherein at least one of the front-facing and rear-facing reflective layers comprise substantially diffusive reflective material.

29. The display of claim 12, comprising a light injection system including a lamp and a light collimator for introducing a non-random fraction of light output by the lamp into the light guide as collimated light within a predetermined range of angles.

30. The display of claim 12, comprising a prismatic turning film positioned between the light guide and the rear-facing reflective layer.

31. The display of claim 12, comprising a brightness enhancement film positioned between the light guide and the rear-facing reflective layer.

32. The display of claim 12, comprising a side-facing reflective layer positioned proximate to a side of the light guide.

33. The display of claim 12, wherein the plurality of geometric light redirectors comprise prismatic light redirectors.

34. The display of claim 33, wherein the prismatic light directors have a first surface facing a lamp and a second surface facing away from the lamp, wherein the area of the footprint of the first surface projected onto the front-facing reflective surface is greater than the area of the footprint of the second surface projected onto the front-facing reflective surface.

35. The display of claim 33, wherein the prismatic light directors have a first surface facing a lamp and a second surface facing away from the lamp, wherein the area of the footprint of the first surface projected onto the front-facing reflective surface is substantially equal to the area of the footprint of the second surface projected onto the front-facing reflective surface.

36. The display of claim 12, wherein the plurality of geometric light redirectors comprise refractive light redirectors.

37. A display comprising:

an array of light modulators defining a display surface;

a light guide having front and rear surfaces and a plurality of geometric light redirectors formed therein;

a rear-facing reflective layer, positioned proximate to the display surface, wherein the rear-facing reflective surface has a plurality of apertures formed therein; and

a front-facing reflective layer positioned proximate the rear surface of the light guide,

wherein the plurality of geometric light redirectors comprise prismatic light redirectors, and wherein the prismatic light redirectors have a first surface facing a lamp and a second surface facing away from the lamp, wherein the area of the footprint of the first surface projected onto the front-facing reflective surface is greater than the area of the footprint of the second surface projected onto the front-facing reflective surface.

38. The display of claim 37, wherein the array of light modulators comprises a plurality of MEMs-based light modulators for selectively allowing light passing through the plurality of apertures in the rear-facing reflective layer to contribute to the formation of an image.

39. The display of claim 37, wherein at least 50% of the rear surface of the light guide is substantially parallel to the display surface.

40. The display of claim 37, wherein at least 70% of the rear surface of the light guide is substantially parallel to the display surface.

41. The display of claim 37, wherein at least 90% of the rear surface of the light guide is substantially parallel to the display surface.

42. The display of claim 37, comprising a refractive layer, having a refractive index less than that of a refractive index of the light guide, disposed between the rear-facing reflective layer and the front surface of the light guide.

43. The display of claim 37, wherein the plurality of geometric light redirectors comprise substantially smooth reflective surfaces.

44. The display of claim 37, comprising a light injection system including a lamp and a light collimator for introducing a non-random fraction of light output by the lamp into the light guide as collimated light within a predetermined range of angles.

45. The display of claim 37, comprising a prismatic turning film positioned between the light guide and the rear-facing reflective layer.

46. The display of claim 37, comprising a brightness enhancement film positioned between the light guide and the rear-facing reflective layer.

47. The display of claim 37, comprising a side-facing reflective layer positioned proximate to a side of the light guide.

48. The display of claim 37, wherein the plurality of geometric light redirectors comprise prismatic light redirectors.

49. A display comprising:

an array of light modulators defining a display surface;

a light guide having front and rear surfaces and a plurality of geometric light redirectors formed therein;

a rear-facing reflective layer, positioned proximate to the display surface, wherein the rear-facing reflective surface has a plurality of apertures formed therein; and

a front-facing reflective layer positioned proximate the rear surface of the light guide, wherein the array of light modulators has a light modulator pitch, and the distance between the rear-facing reflective surface and the display surface is less than the light modulator pitch.

50. The display of claim 49, wherein the array of light modulators comprises a plurality of MEMs-based light modulators for selectively allowing light passing through the plurality of apertures in the rear-facing reflective layer to contribute to the formation of an image.

51. The display of claim 49, wherein the rear-facing reflective layer comprises a dielectric mirror.

52. The display of claim 49, wherein the rear-facing reflective layer comprises a metal layer.

53. The display of claim 49, wherein the plurality of geometric light redirectors comprise substantially smooth reflective surfaces.

54. The display of claim 49, wherein the plurality of geometric light redirectors comprise prismatic light redirectors.

55. The display of claim 49, wherein each aperture in the plurality of apertures allows a flux of light to pass through the aperture, and wherein the association between a respective aperture and a respective at least one light modulators comprises a relationship in which substantially the entire flux of light allowed to pass through the respective aperture is modulated by the respective at least one light modulator.

56. A display comprising:

an array of light modulators defining a display surface;

a light guide having front and rear surfaces and a plurality of geometric light redirectors formed therein;

a rear-facing reflective layer, positioned proximate to the display surface, wherein the rear-facing reflective surface has a plurality of apertures formed therein; and

a front-facing reflective layer positioned proximate the rear surface of the light guide, wherein the rear-facing and front-facing reflective layers comprise specular reflective layers.

57. A display comprising:

an array of light modulators defining a display surface;

a light guide having front and rear surfaces and a plurality of geometric light redirectors formed therein;

a rear-facing reflective layer, positioned proximate to the display surface, wherein the rear-facing reflective surface has a plurality of apertures formed therein;

a front-facing reflective layer positioned proximate the rear surface of the light guide, and

a refractive layer, having a refractive index less than that of a refractive index of the light guide, disposed between the rear-facing reflective layer and the front surface of the light guide.