Structured Composite Optical Films

• US 20070236939A1
• Filed: 03/31/2006
• Published: 10/11/2007
• Est. Priority Date: 03/31/2006
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Ouderkirk, Andrew, Hart, Shandon, Thunhorst, Kristin, Fleming, Patrick, Benson, Olester
• Application Number:
  US11/278,336
• Publication Number:
  US 20070236939A1
• Time in Patent Office: Days
• US Class Current: 362/339
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02F 1/133507 Films for enhancing the luminance
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/133611 including means for improving the brightness uniformity
• CPC Class Codes: G02F 2201/54 Arrangements for reducing warping-twist

Abstract

Optical films having structured surfaces are used, inter alia, for managing the propagation of light within a display. As displays become larger, it becomes more important that the film be reinforced so as to maintain rigidity. An optical film of the invention has a first layer comprising inorganic fibers embedded within a polymer matrix. The first layer has a structured surface to provide an optical function to light passing therethrough. The film may have various beneficial optical properties, for example, light that propagates substantially perpendicularly through the first layer may be subject to no more than a certain level of haze or light incident on the film may be subject to a minimum value of brightness gain. Various methods of manufacturing the films are described.

Claims

1. An optical film, comprising:

a first layer comprising inorganic fibers embedded within a polymer matrix, the first layer having a first structured surface, wherein the first layer provides a brightness gain of at least 10% to light that propagates through the first layer.

2. An optical film as recited in claim 1, wherein the brightness gain is at least 50%.

3. An optical film as recited in claim 1, wherein the brightness gain is at least 100%.

4. An optical film as recited in claim 1, wherein light that propagates substantially perpendicularly through the first layer is subject to a bulk haze of less than 30%.

5. An optical film as recited in claim 1, further comprising at least one of inorganic nanoparticles, light diffusing particles or hollow particles embedded within the polymer matrix.

6. An optical film as recited in claim 1, wherein the first structured surface comprises a brightness enhancing layer surface.

7. An optical film as recited in claim 1, wherein the first structured surface comprises a plurality of prismatic ribs.

8. An optical film as recited in claim 1, wherein the first structured surface comprises a plurality of retroreflecting elements.

9. An optical film as recited in claim 1, wherein the first structured surface comprises one or more lenses.

10. An optical film as recited in claim 9, wherein the one or more lenses comprise at least one Fresnel lens.

11. An optical film as recited in claim 1, wherein the first structured surface comprises one of a diffractive surface and a light collecting surface.

12. An optical film as recited in claim 1, wherein the first layer has a second structured surface facing away from the first structured surface.

13. An optical film as recited in claim 12, wherein a pattern of the first structured surface is registered to a pattern of the second structured surface.

14. An optical film as recited in claim 1, further comprising a second layer attached to the first layer.

15. An optical film as recited in claim 14, wherein the second layer comprises one of a reflective layer, a transmissive layer, a diffusive layer and a layer having a second structured surface.

16. An optical film as recited in claim 14, wherein the second layer comprises a polarizer layer.

17. An optical film as recited in claim 16, wherein the polarizer layer comprises a reflective polarizer layer.

18. An optical film as recited in claim 16, wherein the polarizer layer comprises an absorbing polarizer layer.

19. An optical film as recited in claim 14, wherein the second layer is attached to the first structured surface.

20. An optical film as recited in claim 14, wherein the second layer is attached to a surface facing away from the first structured surface.

21. An optical film as recited in claim 14, further comprising a third layer attached to one of the first and second layers.

22. An optical film as recited in claim 21, wherein the third layer is attached to the second layer and the third layer comprises inorganic fibers embedded within a polymer matrix.

23. An optical film as recited in claim 1, wherein the polymer matrix comprises a thermosetting polymer.

24. An optical film as recited in claim 1, wherein the polymer matrix comprises a thermoplastic polymer.

25. An optical film as recited in claim 1, wherein the polymer matrix comprises a polymer having a value of T_g less than 120°

C.

26. An optical film as recited in claim 1, wherein a single pass transmission through the film for light directed substantially normally a surface of the film facing away from the structured surface is less than 40%.

27. An optical film as recited in claim 26, wherein the single pass transmission is less than 10%.

28. An optical film as recited in claim 1, wherein light directed to the film, having a principal ray at an angle of more 30°

to a film normal, is transmitted out of the film with the principal ray propagating at an angle of less than 25°

to the film normal.

29. An optical film as recited in claim 1, wherein when light is incident on the optical film, the light having a principal ray propagating in a first direction when incident on the optical film, the light is transmitted out of the film with the principal ray propagating in a second direction different from the first direction by at least 5°

.

57. A display system, comprising:

a display unit;

a backlight; and

an optical film as recited in claim 1 disposed between the display unit and the backlight.

30. An optical film, comprising:

a first layer comprising inorganic fibers embedded within a polymer matrix, the first layer having a first structured surface wherein the single pass transmission for light, substantially normally incident on a side of the first layer facing away from the first structured surface, is less than 40%.

31. An optical film as recited in claim 30, wherein the single pass transmission is less than 10%.

32. An optical film as recited in claim 30, wherein the single pass transmission is less than 5%.

33. An optical film as recited in claim 30, wherein light that propagates substantially perpendicularly through the first layer is subject to a bulk haze of less than 30%.

34. An optical film as recited in claim 30, further comprising at least one of inorganic nanoparticles, light diffusing particles or hollow particles embedded within the polymer matrix.

35. An optical film as recited in claim 30, wherein the first structured surface comprises a brightness enhancing layer surface.

36. An optical film as recited in claim 30, wherein the first structured surface comprises a plurality of prismatic ribs.

37. An optical film as recited in claim 30, wherein the first structured surface comprises a plurality of retroreflecting elements.

38. An optical film as recited in claim 30, wherein the first structured surface comprises one or more lenses.

39. An optical film as recited in claim 38, wherein the one or more lenses comprise at least one Fresnel lens.

40. An optical film as recited in claim 30, wherein the first structured surface comprises one of a diffractive surface and a light collecting surface.

41. An optical film as recited in claim 30, wherein the first layer has a second structured surface facing away from the first structured surface.

42. An optical film as recited in claim 41, wherein a pattern of the first structured surface is registered to a pattern of the second structured surface.

43. An optical film as recited in claim 30, further comprising a second layer attached to the first layer.

44. An optical film as recited in claim 43, wherein the second layer comprises one of a reflective layer, a transmissive layer, a diffusive layer and a layer having a structured surface.

45. An optical film as recited in claim 43, wherein the second layer comprises a polarizer layer.

46. An optical film as recited in claim 45, wherein the polarizer layer comprises a reflective polarizer layer.

47. An optical film as recited in claim 45, wherein the polarizer layer comprises an absorbing polarizer layer.

48. An optical film as recited in claim 43, wherein the second layer is attached to the first structured surface.

49. An optical film as recited in claim 43, wherein the second layer is attached to a surface facing away from the first structured surface.

50. An optical film as recited in claim 43, further comprising a third layer attached to one of the first and second layers

51. An optical film as recited in claim 50, wherein the third layer is attached to the second layer and the third layer comprises a polymer matrix having inorganic fibers embedded within a polymer matrix.

52. An optical film as recited in claim 30, wherein the polymer matrix comprises a thermosetting polymer.

53. An optical film as recited in claim 30, wherein the polymer matrix comprises a thermoplastic polymer.

54. An optical film as recited in claim 30, wherein the polymer matrix comprises a polymer having a value of T_g less than 120°

C.

55. An optical film as recited in claim 30, wherein light directed to the film, having a principal ray at an angle of more 30°

to a film normal, is transmitted out of the film with the principal ray propagating at an angle of less than 25°

to the film normal.

56. An optical film as recited in claim 30, wherein when light is incident on the optical film, the light having a principal ray propagating in a first direction when incident on the optical film, the light is transmitted out of the film with the principal ray propagating in a second direction different from the first direction by at least 5°

.

58. A display system, comprising:

a display unit;

a backlight; and

an optical film as recited in claim 30 disposed between the display unit and the backlight.