Backlight module

• US 8,746,909 B2
• Filed: 11/18/2011
• Issued: 06/10/2014
• Est. Priority Date: 04/29/2011
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Chen, Ming-Lung, Hsieh, Kun-Hung
• Primary Examiner(s): Williams, Joseph L
• Application Number:
  US13/300,250
• Publication Number:
  US 20120275139A1
• Time in Patent Office: 935 Days
• Field of Search: 362/97.1, 362/607, 362/612, 362/616, 362/606, 362/609, 362/611, 362/64
• US Class Current: 362/97.1
• CPC Class Codes: G02B 6/0021 for housing at least a part of the light source, e.g. by forming holes or recesses
• CPC Class Codes: G02B 6/0025 Diffusing sheet or layer; Prismatic sheet or layer
• CPC Class Codes: G02B 6/003 Lens or lenticular sheet or layer
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• 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

Abstract

A backlight module is disclosed, which includes plural light sources, a light guide plate, a light scattering device, a high-reflectance microstructure formed on the light guide plate, and a high-diffusion microstructure formed on the light guide plate. The light guide plate has a first surface and a second surface opposite to the first surface. The first surface faces the light sources. The light scattering device is disposed between the light sources and the light guide plate. The high-reflectance microstructure is formed on the second surface. The high-diffusion microstructure is formed on or indented inwardly from the first surface.

Claims

1. A backlight module comprising:

a plurality of light sources;

a light guide plate having a first surface and a second surface opposite to the first surface, the first surface facing the light sources;

a light scattering device disposed between the light sources and the light guide plate;

a high-reflectance microstructure formed on the second surface; and

a high-diffusion microstructure formed on or indented inwardly from the first surface.

2. The backlight module of claim 1, wherein a pattern density of the high-reflectance microstructure is gradually reduced from each of the light sources.

3. The backlight module of claim 2, wherein a covering ratio of the high-reflectance microstructure at areas corresponding to the light sources is greater than 70%.

4. The backlight module of claim 2, wherein a covering ratio of the high-reflectance microstructure at areas corresponding to a middle of neighboring light sources is greater than 30%.

5. The backlight module of claim 1, wherein a reflectance of the high-reflectance microstructure is greater than 70%.

6. The backlight module of claim 1, wherein a pattern density of the high-diffusion microstructure is gradually increased from each of the light sources.

7. The backlight module of claim 6, wherein a covering ratio of the high-diffusion microstructure at areas corresponding to the middle of the neighboring light sources is greater than 70%.

8. The backlight module of claim 6, wherein a covering ratio of the high-diffusion microstructure at areas corresponding to the light sources is approximately from 0% to 10%.

9. The backlight module of claim 1, wherein the high-diffusion microstructure is a raised structure formed on the first surface.

10. The backlight module of claim 1, wherein the high-diffusion microstructure is a concave structure indented inwardly from the first surface.

11. The backlight module of claim 1, wherein the light scattering device is disposed on the first surface and comprises a plurality of aspheric cavities, and the light sources are placed in the aspheric cavities, respectively.

12. The backlight module of claim 11, wherein a profile of the aspheric cavities is bullet-shaped.

13. The backlight module of claim 12, further comprising a plurality of lenses disposed on the light sources.

14. The backlight module of claim 13, wherein each of the lenses has a concave profile.

15. The backlight module of claim 11, wherein each of the aspheric cavities has a flat top surface, and the backlight module further comprises a plurality of Fresnel lenses each formed on the flat top surface of one of the aspheric cavities.

16. The backlight module of claim 15, wherein the first surface is a flat surface, and the light scattering device comprises a plurality of Fresnel lenses formed on the first surface.

17. The backlight module of claim 1, further comprising at least one reflector, wherein the reflector has a plurality of openings, and the light sources are disposed respectively in the openings.

18. The backlight module of claim 17, wherein a distance between the light sources and the first surface is less than a distance between the reflector and the first surface.

19. The backlight module of claim 17, further comprising a back plate, wherein the back plate comprises a plurality of recesses, and the light sources are disposed respectively in the recesses.

20. The backlight module of claim 17, wherein the reflector has a plurality of inclined surfaces for defining the openings.

21. The backlight module of claim 1, further comprising a high-diffusion plate disposed on the high-reflectance microstructure.

22. The backlight module of claim 21, wherein a transmittance of the high-diffusion plate is less than 70%.