LIGHT-GUIDE MODULE

• US 20120128298A1
• Filed: 05/10/2011
• Published: 05/24/2012
• Est. Priority Date: 11/23/2010
• Status: Active Grant

• Current Assignee: Genius Electronic Optical Company Limited
• Original Assignee: Genius Electronic Optical Company Limited
• Inventors: TSAO, Ming-Sen, CHANG, Kuo-Wen
• Granted Patent: US 8,687,937 B2
• Time in Patent Office: Days
• US Class Current: 385/27
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0063 for extracting light out both the major surfaces of the light guide
• CPC Class Codes: G06F 3/0428 by sensing at the edges of the touch surface the interruption of optical paths, e.g. an illumination plane, parallel to the touch surface which may be virtual sensing beam interruptions in a planar beam grid of an optical touch-screen G06F3/0421

Abstract

A light-guide module includes a light-guide strip having opposite first and second ends, a light-entry surface disposed at the first end, a light-exit surface extending between the first and second ends, and first and second working surfaces disposed parallel to each other and extending between the first and second ends. One of the first and second working surfaces defines a light-scatter zone and includes a plurality of micro-scatter structures that are disposed within the light-scatter zone and that configure the light-scatter zone with a light-scattering ability that varies from the first end to the second end. The light-guide module also includes a reflecting element disposed to reflect light that exits from the light-guide strip via the first and second working surfaces back into the light-guide strip via the first and second working surfaces, respectively.

Claims

1. A light-guide module comprising:

a light-guide strip having opposite first and second ends, a light-entry surface disposed at said first end, a light-exit surface extending between said first and second ends, and first and second working surfaces disposed parallel to each other and extending between said first and second ends, one of said first and second working surfaces defining a light-scatter zone and including a plurality of micro-scatter structures that are disposed within said light-scatter zone and that configure said light-scatter zone with a light-scattering ability that varies from said first end to said second end; and

a reflecting element disposed to reflect light that exits from said light-guide strip via said first and second working surfaces back into said light-guide strip via said first and second working surfaces, respectively.

2. The light-guide module as claimed in claim 1, wherein said one of said first and second working surfaces has a length-width ratio not smaller than 50.

3. The light-guide module as claimed in claim 1, wherein said one of said first and second working surfaces is formed with a plurality of irregular protrusions within said light-scatter zone, said irregular protrusions serving as said micro-scatter structures.

4. The light-guide module as claimed in claim 3, wherein each of said first and second working surfaces is disposed perpendicular to said light-exit surface.

5. The light-guide module as claimed in claim 3, wherein said micro-scatter structures configure said light-scatter zone with a light-scattering ability that increases from said first end to said second end.

6. The light-guide module as claimed in claim 5, wherein said light-scatter zone has a substantially non-varying width and a surface average roughness that increases from said first end to said second end.

7. The light-guide module as claimed in claim 6, wherein said light-scatter zone satisfies the conditions of:

Ra(0.75L)/Ra(0.25L)≧

2

Ra(0.95L)/Ra(0.25L)≧

5

wherein L represents a length of said light-scatter zone from said first end to said second end, and Ra(0.25L), Ra(0.75L), and Ra(0.95L) represent roughness of said light-scatter zone at distances of 25%, 75%, and 95% of the length of said light-scatter zone from said first end toward said second end, respectively.

8. The light-guide module as claimed in claim 5, wherein said light-scatter zone has a width that increases in a direction from said first end toward said second end, and said light-scatter zone has a surface average roughness that is not smaller than 3 μ

m and not larger than 6 μ

m.

9. The light-guide module as claimed in claim 8, wherein said width of said light-scatter zone is substantially non-varying within a predetermined distance from said second end.

10. The light-guide module as claimed in claim 9, wherein said surface average roughness is not smaller than 4 μ

m and not larger than 5 μ

m.

11. The light-guide module as claimed in claim 3, wherein said micro-scatter structures configure said light-scatter zone with a light-scattering ability that increases from said first end toward said second end and that is stabilized adjacent to said second end.

12. The light-guide module as claimed in claim 11, wherein said light-scatter zone has a surface average roughness that increases from said first end toward said second end that is substantially non-varying adjacent to said second end.

13. The light-guide module as claimed in claim 12, wherein said light-scatter zone satisfies the conditions of:

Ra(0.5L)/Ra(0.1L)>

1.5

Ra(0.9L)/Ra(0.1L)>

1.5

0.4<

Ra(0.5L)/Ra(0.9L)<

2

wherein L represents a length of said light-scatter zone from said first end to said second end, and Ra(0.1L), Ra(0.5L) and Ra(0.9L) represent roughness of said micro-scatter zone at distances of 10%, 50% and 90% of the length of said light-scatter zone from said first end toward said second end, respectively.

14. The light-guide module as claimed in claim 1, wherein said light-entry surface is a polished surface, and said second end is a roughened surface.

15. The light-guide module as claimed in claim 1, wherein said light-guide strip further has a rear surface disposed opposite to said light-exit surface, and said reflecting element includes first, second and third reflecting portions disposed such that said first, second and third reflecting portion serve to reflect light that exits from said light-guide strip via said first and second working surfaces and said rear surface back into said light-guide strip via said first and second working surfaces and said rear surface, respectively.

16. The light-guide module as claimed in claim 1, further comprising:

a housing for receiving said light-guide strip and said reflecting element; and

a diffuser disposed corresponding to said light-exit surface and serving to scatter light that exits from said light-guide strip via said light-exit surface.

17. The light-guide module as claimed in claim 16, further comprising a light-extinguishing element disposed in said housing at said second end of said light-guide strip.

18. The light-guide module as claimed in claim 5, wherein said irregular protrusions have a distribution density that increases toward said second end.

19. The light-guide module as claimed in claim 6, wherein said light-scatter zone is rectangular.

20. The light-guide module as claimed in claim 1, wherein said light-guide strip has a uniform cross-section along a length thereof.