Perforated multi-layer optical film luminaire

• US 20060268554A1
• Filed: 05/31/2005
• Published: 11/30/2006
• Est. Priority Date: 05/31/2005
• Status: Active Grant

• Current Assignee: University of British Columbia
• Original Assignee: University of British Columbia
• Inventors: Whitehead, Lorne A.
• Granted Patent: US 7,591,094 B2
• Time in Patent Office: Days
• US Class Current: 362/341
• CPC Class Codes: G09F 13/0409 Arrangements for homogeneous illumination of the display surface, e.g. using a layer having a non-uniform transparency arrangements of reflectors G09F13/14
• CPC Class Codes: G09F 13/14 Arrangements of reflectors therein

Abstract

The light emitting surface of an image display light box is formed of multi-layer optical film having a reflectance greater than 95% and preferably about 99% or greater. This more efficiently utilizes light rays emitted by the light box'"'"'s internal light source, since the multi-layer optical film reflects the light rays many times before the rays are absorbed and lost. Consequently, the light emitting surface can have a light transmissivity characteristic which is macroscopically invariant as a function of position on the light emitting surface. Light boxes utilizing prior art reflective materials require cumbersome, time-consuming, iterative trial and error techniques which must be customized for each light box in order to compensate for light absorption losses by imparting a variable transmissivity characteristic to the reflective material.

Claims

1. An image display light box, comprising a light emitting surface having an intrinsic reflectance value greater than 95% and having an extrinsic reflectance-reducing characteristic giving the light emitting surface a light transmissivity characteristic of less than 5%, the transmissivity characteristic being macroscopically invariant as a function of position on the light emitting surface.

2. An image display light box as defined in claim 1, further comprising interior surfaces having an intrinsic reflectance value greater than 95%.

3. An image display light box as defined in claim 1, further comprising a light source and wherein the light emitting surface is perforated to enable a preselected fraction of light rays emitted by the light source to be transmitted through the light emitting surface without reflection.

4. An image display light box as defined in claim 1, further comprising a light source and wherein one or more selected portions of the light emitting surface are removed to enable a preselected fraction of light rays emitted by the light source to be transmitted through the light emitting surf-ace without reflection.

5. An image display light box as defined in claim 1, further comprising a light source and wherein the light emitting surface is disrupted to enable a preselected fraction of light rays emitted by the light source to be transmitted through the light emitting surface without reflection.

6. An image display light box as defined in claim 1, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

7. An image display light box as defined in claim 2, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

8. An image display light box as defined in claim 3, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

9. An image display light box as defined in claim 4, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

10. An image display light box as defined in claim 5, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

11. An image display light box as defined in claim 6, wherein the light emitting surface further comprises multi-layer optical film.

12. An image display light box as defined in claim 7, wherein the light emitting surface further comprises multi-layer optical film.

13. An image display light box as defined in claim 8, wherein the light emitting surface further comprises multi-layer optical film.

14. An image display light box as defined in claim 9, wherein the light emitting surface further comprises multi-layer optical film.

15. An image display light box as defined in claim 10, wherein the light emitting surface further comprises multi-layer optical film.

16. An image display light box as defined in claim 11, further comprising a light source and wherein a diffusive material is optically coupled to the light emitting surface to enable a preselected fraction of light rays emitted by the light source to be transmitted through the light emitting surface without reflection.

17. A high dynamic range image display light box, comprising:

(a) a light emitting surface having;

(i) an inward side and an outward side;

(ii) a first portion comprising;

(1) a substantial area of the light emitting surface;

(2) an intrinsic reflectance value greater than 95%;

(3) a first extrinsic reflectance-reducing characteristic giving the first portion a first light transmissivity characteristic of less than 5%, the first light transmissivity characteristic being macroscopically invariant as a function of position over the first portion;

(iii) a second portion comprising;

(1) the area of the light emitting surface excluding the first portion;

(2) a second extrinsic reflectance-reducing characteristic giving the second portion a second light transmissivity characteristic of greater than 25%;

(b) a sheet extending substantially parallel to and in close proximity to the outward side of the light emitting surface, the sheet bearing an image having;

(i) one or more normal luminance display regions, each normal luminance display region having;

(1) the same size and shape as a corresponding segment of the first portion of the light emitting surface;

(2) a third light transmissivity characteristic which varies as a selected function of a desired normal luminance characteristic of the image;

(ii) one or more high luminance display regions, each high luminance display region having;

(1) the same size and shape as a corresponding segment of the second portion of the light emitting surface; and

(2) a fourth light transmissivity characteristic which varies as a selected function of a desired high luminance characteristic of the image;

wherein the third light transmissivity characteristic and the fourth light transmissivity characteristic are selected such that the first, second, third and fourth light transmissivity characteristics together impart a high dynamic range to the image when the inward side of the light emitting surface is backlit.

18. An image display light box as defined in claim 17, further comprising interior surfaces having an intrinsic reflectance value greater than 95%.

19. An image display light box as defined in claim 17, further comprising a light source and wherein the first extrinsic reflectance-reducing characteristic is provided by perforating the first portion of the light emitting surface to enable a preselected fraction of light rays emitted by the light source to be transmitted through the first portion of the light emitting surface without reflection.

20. An image display light box as defined in claim 17, further comprising a light source and wherein the first extrinsic reflectance-reducing characteristic is provided by removing one or more selected segments of the first portion of the light emitting surface to enable a preselected fraction of light rays emitted by the light source to be transmitted directly through the first portion of the light emitting surface without reflection.

21. An image display light box as defined in claim 17, further comprising a light source and wherein the first extrinsic reflectance-reducing characteristic is provided by disrupting the first portion of the light emitting surface to enable a preselected fraction of light rays emitted by the light source to be transmitted through the first portion of the light emitting surface without reflection.

22. An image display light box as defined in claim 17, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

23. An image display light box as defined in claim 18, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

24. An image display light box as defined in claim 19, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

25. An image display light box as defined in claim 20, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

26. An image display light box as defined in claim 21, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

27. An image display light box as defined in claim 22, wherein the light emitting surface further comprises multi-layer optical film.

28. An image display light box as defined in claim 23, wherein the light emitting surface further comprises multi-layer optical film.

29. An image display light box as defined in claim 24, wherein the light emitting surface further comprises multi-layer optical film.

30. An image display light box as defined in claim 25, wherein the light emitting surface further comprises multi-layer optical film.

31. An image display light box as defined in claim 26, wherein the light emitting surface further comprises multi-layer optical film.

32. An image display light box as defined in claim 27, further comprising a light source and wherein a diffusive material is optically coupled to the second portion of the light emitting surface to enable a preselected fraction of light rays emitted by the light source to be transmitted through the second portion of the light emitting surface without reflection.

33. A light box luminance compensation method, comprising forming a light emitting surface having an intrinsic reflectance value greater than 95% and altering a light transmissivity characteristic of the light emitting surface uniformly as a function of position on the light emitting surface to enable a preselected fraction of light rays incident on the light emitting surface to be transmitted through the light emitting surface without reflection.

34. A light box luminance compensation method as defined in claim 33, wherein altering a light transmissivity characteristic of the light emitting surface further comprises perforating the light emitting surface.

35. A light box luminance compensation method as defined in claim 33, wherein altering a light transmissivity characteristic of the light emitting surface further comprises removing one or more selected portions of the light emitting surface.

36. A light box luminance compensation method as defined in claim 33, wherein altering a light transmissivity characteristic of the light emitting surface further comprises disrupting the light emitting surface'"'"'s reflectance.

37. A light box luminance compensation method as defined in claim 33, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

38. A light box luminance compensation method as defined in claim 34, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

39. A light box luminance compensation method as defined in claim 35, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

40. A light box luminance compensation method as defined in claim 36, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

41. A light box luminance compensation method as defined in claim 37, wherein the light emitting surface is formed of multi-layer optical film.

42. A light box luminance compensation method as defined in claim 38, wherein the light emitting surface is formed of multi-layer optical film.

43. A light box luminance compensation method as defined in claim 39, wherein the light emitting surface is formed of multi-layer optical film.

44. A light box luminance compensation method as defined in claim 40, wherein the light emitting surface is formed of multi-layer optical film.

45. A light box luminance compensation method as defined in claim 41, wherein altering a light transmissivity characteristic of the light emitting surface further comprises optically coupling a diffusive material to the light emitting surface.

46. A high dynamic range image display method, comprising:

applying a static image to a sheet, the image having one or more normal luminance display regions and one or more high luminance display regions;

forming a light emitting surface of a material having an intrinsic reflectance value greater than 95%;

positioning an outward side of the light emitting surface substantially parallel to and in close proximity to the sheet;

dividing the light emitting surface into a first portion comprising a substantial area of the light emitting surface and a second portion comprising the area of the light emitting surface excluding the first portion;

subdividing the first portion of the light emitting surface to provide one light emitting surface first portion segment for each one of the normal luminance display regions, each light emitting surface first portion segment having the same size and shape as a corresponding one of the normal luminance display regions;

subdividing the second portion of the light emitting surface to provide one light emitting surface second portion segment for each one of the high luminance display regions, each light emitting surface second portion segment having the same size and shape as a corresponding one of the high luminance display regions;

altering a light transmissivity characteristic of the first portion of the light emitting surface to give the first portion a macroscopically positionally invariant first light transmissivity characteristic of less than 5%;

altering a light transmissivity characteristic of the second portion of the light emitting surface to give the second portion a second light transmissivity characteristic of greater than 25%;

altering a light transmissivity characteristic of the normal luminance display regions to give the normal luminance display regions a third light transmissivity characteristic which varies as a selected function of a desired normal luminance characteristic of the image;

altering a light transmissivity characteristic of the high luminance display regions to give the high luminance display regions a fourth light transmissivity characteristic which varies as a selected function of a desired high luminance characteristic of the image; and

backlighting an inward side of the light emitting surface;

wherein the third light transmissivity characteristic and the fourth light transmissivity characteristic are selected such that the first, second, third and fourth light transmissivity characteristics together impart a high dynamic range to the image when the inward side of the light emitting surface is backlit.

47. A high dynamic range image display method as defined in claim 46, wherein altering a light transmissivity characteristic of the first portion of the light emitting surface further comprises perforating the first portion of the light emitting surface.

48. A high dynamic range image display method as defined in claim 46, wherein altering a light transmissivity characteristic of the first portion of the light emitting surface further comprises removing one or more selected areas of the first portion of the light emitting surface.

49. A high dynamic range image display method as defined in claim 46, wherein altering a light transmissivity characteristic of the first portion of the light emitting surface further comprises disrupting the reflectance of the first portion of the light emitting surface.

50. A high dynamic range image display method as defined in claim 46, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

51. A high dynamic range image display method as defied in claim 47, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

52. A high dynamic range image display method as defined in claim 48, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

53. A high dynamic range image display method as defined in claim 49, wherein the light emitting surface has an intrinsic reflectance value of about 99% or greater.

54. A high dynamic range image display method as defined in claim 50, wherein the light emitting surface is formed of multi-layer optical film.

55. A high dynamic range image display method as defined in claim 51, wherein the light emitting surface is formed of multi-layer optical film.

56. A high dynamic range image display method as defined in claim 52, wherein the light emitting surface is formed of multi-layer optical film.

57. A high dynamic range image display method as defined in claim 53, wherein the light emitting surface is formed of multi-layer optical film.

58. A high dynamic range image display method as defined in claim 54, wherein altering a light transmissivity characteristic of the first portion segments further comprises optically coupling a diffusive material to the light emitting surface.