Long curved wedges in an optical film

• US 20060092490A1
• Filed: 11/03/2005
• Published: 05/04/2006
• Est. Priority Date: 11/04/2004
• Status: Active Grant

• Current Assignee: Innovative Display Technologies LLC (Acacia Research Corporation)
• Original Assignee: Solid State Opto Limited (Global Lighting Technologies Inc.)
• Inventors: McCollum, Timothy A., Parker, Jeffery R., Lee, Junwon, Sudol, Ronald J., Bourdelais, Robert, Brickey, Cheryl, Brophy, Chris
• Granted Patent: US 7,367,705 B2
• Time in Patent Office: Days
• US Class Current: 359/24
• CPC Class Codes: F21V 7/09 with a combination of different curvatures
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• CPC Class Codes: G02B 5/0221 the surface having an irregular structure G02B5/0226 takes precedence
• CPC Class Codes: G02B 5/0278 used in transmission
• CPC Class Codes: G02B 5/045 Prism arrays
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

The invention relates to a light redirecting polymeric film comprising a plurality of polymeric individual optical elements wherein the elements comprise curved wedge shaped features in the plane of the film, having a length in the range of 800 to 4000 micrometers.

Claims

1. A light redirecting film comprising a plurality of individual polymeric optical elements on or in at least one surface of a polymeric film or substrate, wherein said optical elements have at least two surfaces, at least one of said surfaces being curved, and said optical elements having a length in the range of 800 to 4000 micrometers.

2. The film of claim 1 wherein said optical elements have one curved surface and one planar surface.

3. The film of claim 1 wherein said optical elements have at least two curved surfaces

4. The film of claim 1 wherein said optical elements have at least one asymmetrical shaped surface.

5. The film of claim 1 wherein said optical elements are rotated relative to one another.

6. The film of claim 1 wherein about half of said optical elements are rotated 180 degrees relative to the remaining optical elements.

7. The film of claim 1 wherein said optical elements are staggered with respect to one another and intersect one another.

8. The film of claim 1 wherein said optical elements are opposite each other in a mirror arrangement.

9. The film of claim 1 wherein said optical elements are randomly placed.

10. The film of claim 1 wherein said optical elements are generally aligned.

11. The film of claim 1 wherein said optical elements have at least one curved surface with a radius of curvature of between 0.8 and 20 millimeters.

12. The film of claim 1 wherein said optical elements have a width of between 20 and 300 micrometers.

13. The film of claim 1 wherein said optical elements have a maximum ridge height of the feature of between 10 and 150 micrometers.

14. The film of claim 1 wherein said optical elements have a cross section with an 80-110 degree included angle at the highest point of said optical elements.

15. The film of claim 1 wherein said optical elements have a distance between the highest points of two adjacent optical elements that provides an average pitch of between 10 and 100 micrometers.

16. The film of claim 1 wherein said light redirecting film is an integral structure, wherein said optical elements and said polymeric film or substrate bearing the optical elements is a unitary structure having no transition point between the optical elements and any remaining portion of the polymeric film or substrate.

17. The film of claim 1 wherein said polymeric film or substrate is made of polycarbonate.

18. The film of claim 1 wherein said polymeric film or substrate has an index of refraction of between 1.40 and 2.00.

19. The film of claim 1 wherein said light redirecting film has an on-axis gain of at least 1.3.

20. The film of claim 1 wherein said polymeric film or substrate has first and second surfaces, wherein at least one of said surfaces includes one or more of a texture, coating, dye, light emitting layer, matte finish, diffuse finish, specular finish, and optically smooth finish.

21. The film of claim 1 wherein said polymeric film or substrate has first and second surfaces, wherein at least one of said surface includes said optical elements and the other said surface includes one or more of a texture, coating, dye, light emitting layer, matte finish, diffuse finish, specular finish, and optically smooth finish.

22. The film of claim 1 wherein said polymeric film or substrate has first and second surfaces with at least one of said surfaces comprising optical elements having one or more of a texture, coating, dye, light emitting layer, matte finish, diffuse finish, specular finish, and optically smooth finish.

23. A display system comprising a backlight assembly having at least one light source and at least one light redirecting film for redirecting light received from said backlight assembly, said light redirecting film comprising a polymeric film or substrate having a plurality of individual polymeric optical elements on or in at least one surface of said polymeric film or substrate, wherein said optical elements have at least two surfaces, at least one of said surfaces being curved, and said optical elements have a length in the range of 800 to 4000 micrometers.

24. The display system of claim 23 comprising said one light redirecting film and further comprising a second light redirecting film.

25. The display system of claim 24 wherein said second light redirecting film is rotated at 80 to 100 degrees relative to the length direction of the individual optical elements on said first light redirecting film.

26. The display system of claim 23 further comprising at least one diffusing film.

27. The display system of claim 23 wherein at least some of said optical elements only have two surfaces.

28. The display system of claim 27 wherein said two surfaces of said optical elements are asymmetric.

29. The display system of claim 23 wherein said optical elements have at least one asymmetrical shaped surface

30. The display system of claim 23 wherein said optical elements are on the far surface of the light redirecting film relative to the light source.

31. The display system of claim 23 wherein said optical elements are on the near surface of the light redirecting film relative to the light source.

32. The display system of claim 23 wherein said optical elements are on both the far surface and the near surface of the light redirecting film relative to the light source.

33. The display system of claim 23 wherein at least some of said optical elements have one curved surface and one planar surface.

34. The display system of claim 23 wherein said optical elements are randomly placed.

35. The display system of claim 23 wherein said optical elements are generally aligned.

36. The display system of claim 23 wherein said optical elements are placed such that the film has at least 95% surface coverage of said optical elements over any LC pixel area.

37. The display system of claim 23 wherein said optical elements have a radius of curvature of between 0.8 and 20 millimeters.

38. The display system of claim 23 wherein moiré

is not visible through said display system.