INPUT EDGE COUPLER

• US 20110228559A1
• Filed: 11/23/2009
• Published: 09/22/2011
• Est. Priority Date: 11/24/2008
• Status: Active Grant

• Current Assignee: 3M Innovative Properties Company (3M Company)
• Original Assignee: 3M Innovative Properties Company (3M Company)
• Inventors: Kinder, Brian A.
• Granted Patent: US 8,882,328 B2
• Time in Patent Office: Days
• US Class Current: 362/608
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces

Abstract

A light guide includes a substrate having opposing first and second major surfaces and an input edge coupler disposed along an edge of the substrate. The ratio of a light guide input edge thickness to a light guide thickness is greater than 2:1.

Claims

1. A light guide, comprising:

a first flexible layer having a first flexible layer thickness and opposing first and second major surfaces; and

a second flexible layer having a second flexible layer thickness and opposing first and second major surfaces, wherein the first major surface of the first flexible layer is in physical contact with the second major surface of the second flexible layer, and wherein the second flexible layer further integrally comprises;

a plurality of discrete light extractors capable of extracting light propagating in the light guide such that light is extracted in a pre-determined extraction pattern over the first major surface of the second flexible layer; and

an input edge coupler capable of bringing light from at least one exterior light source into propagation within the light guide, comprising;

an input edge having an input edge thickness disposed along an edge of the light guide, the input edge suited for receiving light from the at least one exterior light source; and

a taper region.

2. The light guide of claim 1, wherein the input edge coupler further comprises a plateau region disposed between the input edge and the taper region.

3. The light guide of claim 1, wherein the pre-determined extraction pattern is a uniform luminance distribution.

5. The light guide of claim 1, wherein the taper region tapers from the input edge thickness to the second flexible layer thickness with a taper angle having a value between about 1 and about 10 degrees.

6. The light guide of claim 1, wherein the first flexible layer comprises a material selected from the group consisting of polymethylmethacrylate, polycarbonate, and polyethylene terephthalate, and further wherein the second flexible layer comprises UV-curable acrylate resin.

7. The light guide of claim 1, wherein a first flexible layer index of refraction is less than or equal to a second flexible layer index of refraction.

8. The light guide of claim 1, wherein a first flexible layer index of refraction is greater than a second flexible layer index of refraction.

9. The light guide of claim 1, wherein the first and second flexible layers comprise different materials.

11. The light guide of claim 1, wherein the input edge exhibits a first microstructure different than a second microstructure exhibited by at least one other edge of the light guide.

4. (canceled)

10. (canceled)

12. A light guide, comprising:

a flexible substrate having opposing first and second major surfaces; and

an input edge coupler, comprising;

an input edge disposed along an edge of the substrate, having an input edge thickness; and

a taper region;

wherein the input edge exhibits a first microstructure different than a second microstructure exhibited by at least one other edge of the light guide.

13. A light guide, comprising:

a substrate having opposing first and second major surfaces; and

an input edge coupler disposed along an edge of the substrate;

wherein the ratio of a light guide input edge thickness to a light guide thickness is greater than 2;

1.

14. The light guide of claim 13, wherein the light guide thickness is not greater than 200 micrometers.

15. The light guide of claim 13, wherein the substrate and input edge coupler comprise different materials.

16. A light guide, comprising:

a substrate having opposing first and second major surfaces integrally comprising a tapered input edge coupler; and

a continuous extraction layer in physical contact with the substrate comprising a plurality of discrete light extractors capable of extracting light propagating in the light guide such that light is extracted in a pre-determined extraction pattern over the extraction layer.

17. A light guide, comprising:

a substrate comprising a substrate material and comprising a first major surface and a second major surface; and

an input edge coupler comprising a coupler material, further comprising;

an input edge disposed along an edge of the substrate; and

a taper region;

wherein the substrate material and coupler material are different.

18. The light guide of claim 17, further comprising an extraction layer in physical contact with the first major surface, the extraction layer comprising a plurality of discrete light extractors capable of extracting light propagating in the light guide such that light is extracted uniformly over an extraction region of the extraction layer.

19. The light guide of claim 17, wherein the input edge coupler is in physical contact with the first major surface.

20. The light guide of claim 17, wherein the input edge coupler is in physical contact with the second major surface.

21. An optical system, comprising:

a light guide, comprising;

a first flexible layer having a first flexible layer thickness and opposing first and second major surfaces; and

a second flexible layer having a second flexible layer thickness and opposing first and second major surfaces, wherein the first major surface of the first flexible layer is in physical contact with the second major surface of the second flexible layer, and wherein the second flexible layer further comprises;

a plurality of discrete light extractors capable of extracting light propagating in the light guide such that light is extracted in a pre-determined extraction pattern over the first major surface of the second flexible layer; and

an input edge coupler, comprising;

an input edge disposed along an edge of the light guide, capable of receiving light and having an input edge thickness; and

a taper region;

one or more light sources disposed to emit light into the light guide via the input edge; and

a light valve panel disposed to receive light extracted over the first major surface of the second flexible layer of the light guide.

22. A web, comprising:

a flexible substrate having a flexible substrate thickness and opposing first and second major surfaces, the flexible substrate having a ratio of downweb dimension to crossweb dimension of at least 10;

1; and

a flexible extraction layer having a flexible extraction layer thickness and opposing first and second major surfaces, wherein the first major surface of the flexible substrate is in physical contact with the second major surface of the flexible extraction layer, and wherein the flexible extraction layer further comprises at least one light guide region comprising;

a plurality of discrete light extractors capable of extracting light propagating in the flexible substrate such that light is extracted in a pre-determined extraction pattern over the at least one light guide region of the flexible extraction layer; and

an input edge coupler, comprising;

a plateau region disposed along an edge of the at least one light guide region, characterized by a plateau thickness; and

a taper region adjacent the plateau region;

wherein the web may be converted to result in a plurality of light guides.

23. The web of claim 22, further comprising a support layer attached to the flexible substrate.

24. A method for manufacturing light guides, comprising the steps of:

providing a flexible substrate having a flexible substrate thickness and opposing first and second major surfaces;

disposing a flexible layer onto the flexible substrate, the flexible layer having a flexible layer thickness and opposing first and second major surfaces such that the first major surface of the flexible substrate is in physical contact with the second major surface of the flexible layer;

microreplicating at least one light guide region on the flexible layer, further comprising the steps of;

microreplicating a plurality of discrete light extractors capable of extracting light propagating in the flexible substrate such that light is extracted in a pre-determined extraction pattern over the at least one light guide region of the flexible layer; and

microreplicating an input edge coupler, the input edge coupler comprising;

a plateau region disposed along an edge of the at least one light guide region, characterized by a plateau thickness; and

a taper region adjacent the plateau region;

converting the flexible substrate and flexible layer to result in a plurality of light guides.

25. The method of claim 24, wherein the step of microreplicating at least one light guide region on the flexible layer includes simultaneously performing the steps of microreplicating a plurality of light extractors and microreplicating an input edge coupler.

26. The method of claim 24, wherein the step of disposing a flexible layer onto the flexible substrate comprises microreplicating the flexible layer onto the flexible substrate.