Adhesive stacking for multiple optical films

• US 20050046767A1
• Filed: 08/29/2003
• Published: 03/03/2005
• Est. Priority Date: 08/29/2003
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Kotchick, Keith M., Freking, Anthony J.
• Granted Patent: US 7,413,336 B2
• Time in Patent Office: Days
• US Class Current: 349/62
• CPC Class Codes: B32B 43/006 Delaminating
• CPC Class Codes: G02B 7/00 Mountings, adjusting means, or light-tight connections, for optical elements
• CPC Class Codes: G02F 1/1335 Structural association of cells with optical devices, e.g. polarisers or reflectors
• CPC Class Codes: G02F 1/133507 Films for enhancing the luminance
• CPC Class Codes: G02F 2202/28 Adhesive materials or arrangements

Abstract

In a new packaging method for light management films in displays, such as liquid crystal displays, a stack of two or more optical films is held together before insertion into the display frame. The stack includes at least two of the films that are adhered together using adhesive positioned outside the viewing area of the films. In some embodiments, the adhesive is provided at one or more tabs provided around the periphery of the film stack.

Claims

1. A light management film package for managing light within a display, comprising:

a stack of at least first and second optical films, each of the at least first and second optical films having at least one peripheral tab, the at least one peripheral tabs of the at least first and second optical films being in relative alignment, and a layer of adhesive disposed between the at least one peripheral tabs to adhere the at least first and second optical films to each other.

2. A film package as recited in claim 1, wherein the first and second optical films each have respective peripheral edges in registration, at least a portion of at least one peripheral edge of the first optical film being adhered together with at least one peripheral edge of the second optical film by adhesive.

3. A film package as recited in claim 1, wherein the first optical film is a prismatic, light directing film having a prismatically structured surface towards the second optical film.

4. A film package as recited in claim 3, wherein the second optical film is a prismatic, light directing film having a prismatically structured surface on a side of the second optical film away from the first optical film, ribs of the prismatically structured surface of the second optical film being oriented substantially perpendicular to ribs of the prismatically structured surface of the first optical film.

5. A film package as recited in claim 1, further comprising at least a third optical film having a third viewing area registered with the first and second viewing areas, the third optical film having at least one peripheral tab adhered to the at least one peripheral tab of the second optical film.

6. A film package as recited in claim 5, wherein the first and second optical films are prismatic, light directing films, and the third optical film is a reflecting polarizer film.

7. A film package as recited in claim 1, further comprising a display element, the stack of at least first and second optical films being attached to the display element.

8. A film package as recited in claim 1, further comprising a backlight unit, the stack of at least first and second optical films being attached to the backlight unit.

9. A film package as recited in claim 1, wherein the at least one peripheral tab on the first and second optical films are disposed around the respective optical films in a non-symmetric pattern.

10. A film package as recited in claim 1, further comprising a lower protective layer on one side of the stack and an upper protective layer on the other side of the stack.

11. A film package as recited in claim 10, wherein the upper and lower protective layers each have major surfaces different in at least one of shape and size from a major surface of the stack.

12. A film package as recited in claim 1, wherein the stack has a viewing area, the layer of adhesive being outside the viewing area.

13. A display system, comprising:

an illumination unit;

a display unit; and

a light management unit disposed between the illumination unit and the display unit to manage light passing from the illumination unit to the display unit, the light management unit comprising

a stack of at least first and second optical films each of the at least first and second optical films having at least one peripheral tab, the at least one peripheral tabs of the at least first and second optical films being in relative alignment, and a layer of adhesive disposed between the at least one peripheral tabs to adhere at least the first and second optical films to each other.

14. A system as recited in claim 13, further comprising a control unit coupled to the display unit to control an image displayed by the display unit.

15. A system as recited in claim 13, wherein the display unit includes a liquid crystal display layer.

16. A system as recited in claim 15, further comprising an absorbing polarizer layer on a viewing side of the liquid crystal display layers and an absorbing polarizer on an illumination unit side of the liquid crystal display layer.

17. A system as recited in claim 13, wherein the illumination unit includes one or more light sources illuminating a light guide panel, light from the one or more light sources entering the light guide panel and passing through a face of the light guide panel to the light management unit.

18. A system as recited in claim 13, further comprising a frame holding the illumination unit, the light management unit and the display unit.

19. A method for stacking optical films for an optical display, comprising:

adhering, with an adhesive layer, a first optical film to a second optical film at portions of the first and second optical films corresponding to peripheral optical tabs; and

cutting the first and second optical films to produce respective first and second optical film segments having respective peripheral tabs;

wherein the first and second optical films form a film stack having aligned and adhered peripheral tabs.

20. A method as recited in claim 19, further comprising adhering the first and second optical films before cutting the first and second optical films.

21. A method as recited in claim 20, wherein cutting the first and second films includes cutting the first and second optical films together.

22. A method as recited in claim 19, further comprising adhering the first and second optical films after cutting the first and second optical films.

23. A method as recited in claim 22, wherein cutting the first and second films includes cutting the first and second optical films separately and then stacking the first and second optical films in alignment and adhering the first and second optical films.

24. A method as recited in claim 19, further including stripping first and second liner layers from the respective first and second optical films.

25. A method as recited in claim 24, wherein cutting the first and second optical films includes cutting through the first and second optical films together to a depth that leaves a liner layer associated with the second optical film uncut.

26. A method as recited in claim 24, wherein adhering the first and second optical films includes laminating the first and second optical films using a pressure sensitive adhesive.

27. A method as recited in claim 24, wherein adhering the first and second optical films includes laminating the first and second optical films using a radiation cured resin.

28. A method as recited in claim 24, wherein adhering the first and second optical films includes laminating the first and second optical films using a hot melt glue.

29. A method as recited in claim 24, wherein adhering the first and second optical films includes laminating the first and second optical films using an epoxy.

30. A method as recited in claim 19, wherein cutting the first and second optical films includes passing the first and second optical films together through a diecutter.

31. A method as recited in claim 19, wherein the first optical film is a prismatic film having prismatic ribs in a first orientation and the second optical film is a prismatic film having prismatic ribs in a second orientation non-parallel to the first orientation.

32. A method as recited in claim 19, wherein providing the first and second optical films includes pulling at least one of the first and second optical films off a roll containing the at least one of the first and second optical films.

33. A method as recited in claim 19, further comprising feeding at least one of the first and second optical films as a cut sheet onto the other of the first and second optical films.

34. A method as recited in claim 19, wherein providing the first and second optical films includes providing at least a third optical film and further comprising stacking at least a third optical film with the first and second optical films.

35. A method as recited in claim 19, further comprising providing a first protective layer on one side of the film stack and a second protective layer on another side of the film stack, the first and second layers each having a major surface different in at least one of size and shape from a major surface of the film stack.

36. A light management film package for managing light within a display, comprising:

a first optical film having a first peripheral edge, at least one first peripheral tab disposed on the first peripheral edge; and

a second optical film disposed over the first optical film, the second optical film having a second peripheral edge, at least one second peripheral tab disposed on the second peripheral edge, the at least one second peripheral tab aligned with the at least one first peripheral tab, the at least one second peripheral tab being adhered to the at least one first peripheral tab with an adhesive to form a film stack.

37. A film package as recited in claim 36, further comprising a third optical film attached to the second optical film.

38. A film package as recited in claim 37, wherein the third optical film includes a third peripheral edge having at least one third peripheral tab aligned with the at least one first and second peripheral tabs, and adhered to the at least one second peripheral tab.

39. A film package as recited in claim 37, wherein the first and second optical films are prismatic, light directing films, and the third optical film is a reflecting polarizer.

40. A film package as recited in claim 36, wherein the first and second optical films each have respective peripheral edges in registration, at least a portion of the first peripheral edge being adhered to a corresponding portion of the second peripheral edge.

41. A film package as recited in claim 36, wherein the first optical film is a prismatic, light directing film having a prismatically structured surface oriented towards the second optical film.

42. A film package as recited in claim 41, wherein the second optical film is a prismatic, light directing film having a substantially flat surface oriented towards the first optical film and a prismatically structured surface with ribs oriented substantially perpendicular to ribs of the prismatically structured surface of the first optical film.

43. A film package as recited in claim 36, further comprising a display element, the film being attached to the display element.

44. A film package as recited in claim 36, further comprising a backlight unit, the film stack being attached to the backlight unit.

45. A film package as recited in claim 36, further comprising a lower protective layer on one side of the stack and an upper protective layer on the other side of the stack.

46. A film package as recited in claim 45, wherein the upper and lower protective layers each have major surfaces different in at least one of shape and size from a major surface of the stack.

47. A film package as recited in claim 36, wherein the stack has a viewing area, the layer of adhesive being outside the viewing area.

48. A display system, comprising:

an illumination unit;

a display unit; and

a light management unit disposed between the illumination unit and the display unit to manage light passing from the illumination unit to the display unit, the light management unit comprising a stack of at least first and second optical films, the first optical film having a first peripheral edge, at least one first peripheral tab disposed on the first peripheral edge, the second optical film being disposed over the first optical film and having a second peripheral edge, at least one second peripheral tab disposed on the second peripheral edge, the at least one second peripheral tab being aligned with the at least one first peripheral tab, the at least one second peripheral tab being adhered to the at least one first peripheral tab with an adhesive..

49. A system as recited in claim 48, further comprising a control unit coupled to the display unit to control an image displayed by the display unit.

50. A system as recited in claim 48, wherein the display unit includes a liquid crystal display layer.

51. A system as recited in claim 50, further comprising an absorbing polarizer layer on a viewing side of the liquid crystal display layers and an absorbing polarizer on a light source side of the liquid crystal display layer.

52. A system as recited in claim 48, wherein the illumination unit includes one or more light sources illuminating a light guide panel, light from the one or more light sources entering the light guide panel and passing through a surface of the light guide panel to the management unit.

53. A system as recited in claim 48, further comprising a frame holding the illumination unit, the light management unit and the display unit.

54. A system as recited in claim 53, wherein at least the first and second optical films of the light management unit include one or more peripheral alignment tabs for locating the light management unit within the frame, the one or more peripheral alignment tabs being attached together with adhesive.