Web Converting Methods for Forming Light Guides and the Light Guides Formed Therefrom

• US 20110222311A1
• Filed: 11/23/2009
• Published: 09/15/2011
• Est. Priority Date: 11/24/2008
• Status: Abandoned Application

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Kinder, Brian A.
• Application Number:
  US13/130,506
• Publication Number:
  US 20110222311A1
• Time in Patent Office: Days
• US Class Current: 362/611
• CPC Class Codes: G02B 6/002 by shaping at least a portion of the light guide, e.g. with collimating, focussing or diverging surfaces
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0041 provided in the bulk of the light guide
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0065 Manufacturing aspects; Material aspects

Abstract

A method of forming a light guide, web structures and light guide structures are described herein. The method includes cutting a web to provide film pieces, where a first major surface of each film piece is capable of emitting light when light is injected into the film piece from a first cut edge of the film piece. The step of cutting produces structures on the first edge of the film.

Claims

1. A method of forming a light guide comprising:

providing a web of a film having a major surface and a web edge; and

cutting the web to provide film pieces, wherein each film piece has a first major surface, a second major surface and at least a first cut edge;

wherein the first major surface of each film piece is capable of emitting light when light is injected into the film piece from the first cut edge of the film piece;

wherein the major surface of each film piece is capable of emitting at least a majority of the light injected into the film piece from the first cut edge;

wherein the step of cutting produces structures on the first edge of the film.

2. The method of claim 1 further comprising the step of:

injecting light into the first edge of the light guide.

3. The method of claim 1 wherein the major surface of the film comprises a plurality of light extractors capable of extracting light propagating in the web.

4. The method of claim 1 wherein the web of the film comprises diffuse particles in a gloss-gloss substrate.

5. The method of claim 1 wherein the step of cutting is performed by a cutting tool having a blade.

6. The method of claim 5 wherein the step of cutting is performed by a rotary razor blade.

7. The method of claim 6 wherein the rotary razor blade has a hone angle of at least 5 degrees and not more than 45 degrees.

8. The method of claim 6 wherein the rotary razor blade is asymmetrical, having a planar surface on one side and having a chisel profile on an opposite side.

9. The method of claim 8 wherein the rotary razor blade is supported by a blade hub on the planar side.

10. The method of claim 6 wherein the blade thickness is at least 10 mils and not more than 35 mils.

11. The method of claim 5 further comprising the step of treating the finish of at least a portion of the blade before the step of cutting the web.

12. The method of claim 11 wherein the step of treating includes coating at least a portion of the blade.

13. The method of claim 12 wherein the coating comprises titanium nitride.

14. The method of claim 11 wherein the step of treating includes sandblasting.

15. The method of claim 6 wherein the rotary razor blade comprises serrations.

16. The method of claim 5 wherein the blade comprises stainless steel.

17. The method of claim 1 further comprising the step of heating the web before the step of cutting the film.

18. The method of claim 5 wherein during the step of cutting the web, the blade is driven to rotate.

19. The method of claim 5 wherein during the step of cutting the web, the web is moving at a web speed in a first direction and the blade is not moved with respect to the web.

20. The method of claim 5 wherein during the step of cutting the web, the web is stationary and the blade is moved linearly with respect to the web at a first speed.

21. The method of claim 5 wherein the step of cutting the web using a cutting tool with a blade is carried out on the first edge, further comprising the step of cutting the remaining edges of the film piece by die-cutting.

22. The method of claim 1 wherein an edge angle formed between a mid-section of a surface of the first edge and a first major surface of the film piece is at least 85 degrees and not more than 95 degrees.

23. The method of claim 22 wherein the edge angle is at least 88 degrees and not more than 92 degrees.

24. The method of claim 1 wherein the structures on the first edge of the film are parallel grooves.

25. The method of claim 24 wherein each film piece has a first major surface, wherein a groove angle is defined between the parallel grooves and a normal to the first major surface of the film, wherein the groove angle is at least 2 degrees.

26. The method of claim 25 wherein the groove angle is at least 10 degrees.

27. The method of claim 1 wherein the web of film includes a carrier liner, wherein the step of cutting the web does not comprise cutting the carrier liner into pieces.

28. The method of claim 1 wherein the step of cutting the web comprises cutting at least partially into the carrier liner.

29. A method of forming a light guide comprising:

providing a web of a film having a major surface and a web edge, wherein the major surface of the film comprises a plurality of light extractors capable of extracting light propagating in the web; and

cutting the web using a rotary razor blade to provide film pieces, wherein each film piece has a first major surface, a second major surface and at least a first cut edge;

wherein the first major surface of each film piece is capable of emitting light when light is injected into the film piece from the first cut edge of the film piece;

wherein the major surface of each film piece is capable of emitting at least a majority of the light injected into the film piece from the first cut edge;

wherein the step of cutting produces parallel groove structures on the first edge of the film.

30. An intermediate product formed during the process of forming a light guide comprising:

a web of a film having;

a first major surface,

a second major surface, and

a first edge, wherein the first edge comprises structures,

wherein the first major surface of the light guide is capable of emitting light when light is injected into the first edge of the web, wherein the first major surface is capable of emitting at least a majority of the light injected into the launch edge.

31. The light guide of claim 30 wherein the first major surface further comprises a plurality of light extractors capable of extracting light propagating in the light guide.

32. The light guide of claim 31 wherein the structures on the launch edge surface of the light guide comprise parallel grooves.

33. The intermediate product of claim 31 wherein the web comprises a first flexible layer and a second flexible layer, the light extractors are present in the first flexible layer and are discrete light extractors capable of extracting light propagating in the light guide such that light is extracted uniformly over substantially the entire first major surface of the first light guide.

34. The method of claim 33 wherein the first flexible layer has a substantially flat land area separating the plurality of discrete light extractors, the average thickness of the land area being no greater than 10 microns.

35. The light guide of claim 30 wherein the root mean square roughness of the launch edge surface is less than 10.0 microns.

36. The light guide of claim 35 wherein the root mean square roughness of the launch edge surface is less than 5.0 microns.

37. An intermediate product formed during the process of forming a light guide comprising:

a web of a film comprising a first flexible layer and a second flexible layer, wherein the web further comprises;

a first major surface of the first flexible layer,

a second major surface of the second flexible layer,

a plurality of light extractors capable of extracting light propagating in the light guide on the first major surface, and

a first edge, wherein the first edge comprises structures,

wherein the first major surface of the light guide is capable of emitting light when light is injected into the first edge of the web, wherein the first major surface is capable of emitting at least a majority of the light injected into the launch edge.

38. A light guide comprising:

a first flexible layer having a first major surface;

a second flexible layer having a second major surface;

a launch edge comprising a launch edge surface, wherein the launch edge surface comprises structures,

wherein the first major surface of the light guide is capable of emitting light when light is injected into the light guide from the launch edge, wherein the first major surface is capable of emitting at least a majority of the light injected into the launch edge; and

wherein the light guide includes;

a first region where thickness does not vary substantially, and

a second region adjacent the edge of the light guide where the thickness of the light guide varies at a first rate.

39. The light guide of claim 38 further comprising:

a light source positioned at the launch edge of the light guide.

40. The light guide of claim 38 wherein the first major surface further comprises a plurality of light extractors capable of extracting light propagating in the light guide.

41. The light guide of claim 38 wherein the structures on the launch edge surface of the light guide comprise parallel grooves.

42. The light guide of claim 38 wherein the root mean square roughness of the launch edge surface is less than 10.0 microns.

43. The light guide of claim 38 wherein the root mean square roughness of the launch edge surface is less than 5.0 microns.