Optical films for controlling angular characteristics of displays

• US 20060077123A1
• Filed: 06/17/2005
• Published: 04/13/2006
• Est. Priority Date: 09/27/2004
• Status: Active Grant

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: IDC, LLC
• Inventors: Gally, Brian J., Cummings, William J.
• Granted Patent: US 7,508,571 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 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

In various embodiments of the invention, an interferometric display device is provided having an external film with a plurality of structures that reduce the field-of-view of the display. These structures may comprise, for example, baffles or non-imaging optical elements such as compound parabolic collectors. The baffles may comprise a plurality of vertically aligned surfaces arranged, e.g., in a grid. In certain preferred embodiments these baffles are opaque or reflective. These vertical surfaces, therefore, can substantially block light from exiting the interferometric display device in a substantially non-perpendicular direction. These vertical surfaces may, however, permit light directed in a substantially vertical direction to exit the display. The non-imaging optical elements, e.g., compound parabolic collectors, redirect light from large incident angles into more normal angles towards the display. As a result, the light reflected by the display to the user is also at a more normal angle.

Claims

1. A display comprising:

a light-modulating array comprising a plurality of light-modulating elements including first and second optical surfaces, the second optical surface movable with respect to the first optical surface; and

a plurality of elements configured to limit a field-of-view of the display.

2. The display of claim 1, wherein the plurality of elements configured to limit a field-of-view of the display comprises a plurality of baffles.

3. The display of claim 2, wherein the plurality of baffles is incorporated in an optical layer formed over the light-modulating array.

4. The display of claim 2, wherein the light-modulating array is in a horizontal plane and the plurality of baffles comprise substantially planar surfaces that are parallel to a vertical plane.

5. The display of claim 2, wherein the plurality of baffles comprise spacings between individual baffles, said spacing having a dimension that provides a view angle of not more than about 40 degrees from a plane normal to a front surface of the display, wherein the angle is measured as a half-angle with respect to the normal plane.

6. The display of claim 2, wherein the plurality of baffles comprise spacings between individual baffles, said spacing having a dimension that provides a view angle of not more than about 20 degrees from a plane normal to a front surface of the display, wherein the angle is measured as a half-angle with respect to the normal plane.

7. The display of claim 2, wherein the plurality of baffles are substantially opaque.

8. The display of claim 7, wherein the plurality of baffles comprise substantially planar opaque surfaces.

9. The display of claim 2, wherein the plurality of baffles comprises absorbing material.

10. The display of claim 2, wherein the plurality of baffles comprises a reflecting material.

11. The display of claim 1, wherein the plurality of elements configured to limit a field-of-view of the display comprises an array of light collectors comprising curved reflective surfaces shaped to collect light incident at a wide range of angles and direct the light into at a narrower range of angles onto the light-modulating elements.

12. The display of claim 11, wherein the plurality of elements restrict the field-of-view of the display to angles no more than about 70 degrees from a plane normal to a front surface of the display, wherein the angle is measured as a half-angle with respect to the normal plane.

13. The display of claim 11, wherein the plurality of elements restrict the field-of-view of the display to angles no more than about 20 degrees from a plane normal to a front surface of the display, wherein the angle is measured as a half-angle with respect to the normal plane.

14. The display of claim 11, wherein said light collectors comprise non-imaging optical elements.

15. The display of claim 14, wherein said non-imaging optical elements comprise compound parabolic collectors.

16. The display of claim 11, wherein said reflective surfaces are symmetric about central optical axes passing through the light collectors.

17. The display of claim 11, wherein said light collectors are circularly symmetric about central optical axes passing through the light collectors.

18. The display of claim 11, wherein said curved reflective surfaces define input and output apertures for said light collectors, said output apertures being larger than said input apertures.

19. The display of claim 11, wherein the curved reflective surfaces are shaped to substantially collimate light.

20. The display of claim 1, further comprising:

a processor that is in electrical communication with the light-modulating array, said processor being configured to process image data;

a memory device in electrical communication with said processor.

21. The display system as recited in claim 20, further comprising:

a first controller configured to send at least one signal to the light-modulating array; and

a second controller configured to send at least a portion of said image data to said first controller.

22. The display system as recited in claim 20, further comprising:

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

23. The display system as recited in claim 22, wherein said image source module comprises at least one of a receiver, transceiver, and transmitter.

24. The display system as recited in claim 20, further comprising:

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

25. A display comprising:

a light-modulating array comprising a plurality of light-modulating elements including first and second optical surfaces, the second optical surface movable with respect to the first optical surface; and

a diffuser element forward of the array configured to diffuse light such that light incident on the diffuser element is directed to the light-modulating elements more collimated than the incident light.

26. The display of claim 25, wherein the diffuser element comprises a plurality of scatter features arranged such that light incident on the diffuser element is directed to the light-modulating elements more collimated than the incident light.

27. The display of claim 25, wherein the diffuser element comprises a diffractive optical element.

28. The display of claim 27, wherein the diffuser element comprises a holographic optical element.

29. The display of claim 25, wherein the diffuser element comprises a multilayer film.

30. The display of claim 29, wherein the multilayer film comprises:

a first layer configured to substantially collimate the light incident on the diffuser element; and

a second layer comprising diffusing material configured to diffuse light reflected from the light-modulating elements.

31. A method of manufacturing a display, the method comprising:

forming a light-modulating array comprising a plurality of light-modulating elements including first and second optical surfaces, the second optical surface movable with respect to the first optical surface; and

forming a plurality of elements configured to limit a field-of-view of the display.

32. The method of claim 31, wherein the plurality of elements configured to limit a field-of-view of the display comprises a plurality of baffles.

33. The method of claim 32, wherein the plurality of baffles is incorporated in an optical layer formed over the light-modulating array.

34. The method of claim 32, wherein the light-modulating array is in a horizontal plane and the baffles are aligned parallel to a vertical plane.

35. The method of claim 32, wherein the plurality of baffles comprise spacings between individual baffles, said spacing having a dimension that provides a view angle is no more than about 40 degrees from a plane normal to a front surface of the display, wherein the angle is measured as a half-angle with respect to the normal plane.

36. The method of claim 32, wherein the plurality of baffles are substantially opaque.

37. The method of claim 36, wherein the plurality of baffles comprise substantially planar opaque surfaces.

38. The method of claim 32, wherein the plurality of baffles comprises absorbing material.

39. The method of claim 32, wherein the plurality of baffles comprises reflecting material.

40. A display formed by the method of manufacturing of claim 32.

41. The method of claim 31, wherein the plurality of elements configured to limit a field-of-view of the display comprises an array of light collectors comprising curved reflective surfaces shaped to collect light incident at a wide range of angles and direct the light into at a narrower range of angles onto the light-modulating elements.

42. The method of claim 41, wherein said light collectors comprise non-imaging optical elements.

43. The method of claim 42, wherein said non-imaging optical elements comprise compound parabolic collectors.

44. The method of claim 41, wherein said reflective surfaces are symmetric about central optical axes passing through the reflective collectors.

45. The method of claim 41, wherein said reflective surfaces are circularly symmetric about central optical axes passing through the reflective collectors.

46. The method of claim 41, wherein said curved reflective surfaces define input and output apertures for said light collectors, said output apertures being larger than said input apertures.

47. The method of claim 41, wherein the curved reflective surfaces are shaped to substantially collimate light.

48. A display formed by the method of manufacturing of claim 41.

49. A method of manufacturing a display, the method comprising:

forming a light-modulating array comprising a plurality of light-modulating elements including first and second optical surfaces, the second optical surface movable with respect to the first optical surface; and

forming a diff-user element forward of the array configured to receive light incident at a wide range of angles and direct the light into at a narrower range of angles onto the light-modulating elements.

50. The method of claim 49, wherein the diff-user element comprises a plurality of scatter features arranged such that the light incident on the diffuser element at a wide range of angles are directed into at a narrower range of angles onto the light-modulating elements.

51. The method of claim 49, wherein the diffuser element comprises a diffractive optical element.

52. The method of claim 51, wherein the diffuser element comprises a holographic optical element.

53. The method of claim 49, wherein the diffuser element comprises a multilayer film.

54. The method of claim 53, wherein the multilayer film comprises:

a first layer configured to substantially to receive light incident at a wide range of angles and direct the light into at a narrower range of angles onto the light-modulating elements; and

a second layer comprising diffusing material configured to diffuse light reflected from the light-modulating elements.

55. A display formed by the method of manufacturing of claim 49.

56. A display comprising:

a light-modulating array comprising a plurality of light-modulating elements including first and second optical surfaces, the second optical surface movable with respect to the first optical surface; and

means for limiting the field-of-view of the light-modulating elements.