Backlight module

• US 7,658,530 B2
• Filed: 05/30/2007
• Issued: 02/09/2010
• Est. Priority Date: 12/06/2006
• Status: Active Grant

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Liu, Pang-Hsuan
• Primary Examiner(s): Husar; Stephen F
• Application Number:
  US11/755,730
• Publication Number:
  US 20080137364A1
• Time in Patent Office: 986 Days
• Field of Search: 362/606, 362/612, 362/613, 362/616, 362/628, 362/620, 362/625, 362/626, 362/618
• US Class Current: 362/606
• CPC Class Codes: G02B 6/0018 Redirecting means on the surface of the light guide
• 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 6/0035 provided on the surface of the light guide or in the bulk of it
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0078 Side-by-side arrangements, e.g. for large area displays

Abstract

A backlight module includes a light guide plate, a light source disposed at a side of the light guide plate, a diffuser sheet positioned over the light guide plate but not directly contacting the light guide plate, and a light mixing space positioned between the light guide plate and the diffuser sheet so that light emitted from the light guide plate efficiently mixes in the light mixing space before entering the diffuser sheet and emitted out of the backlight module.

Claims

1. A backlight module comprising:

a light guide plate having a light-exit face and at least one light-incidence face;

a light source positioned at a side of the light guide plate and separate from the light guide plate, wherein light emitted from the light source enters the light guide plate from the light-incidence face;

a plurality of light guide patterns positioned on the light guide plate partly to guide the light toward the light-exit face and to make the light passing through the light-exit face become a plurality of line-like sources;

a diffuser sheet positioned on the light guide plate without contacting the light guide plate and the light source, and the diffuser sheet being parallel to the light-exit face of the light guide plate; and

a light mixing space disposed between the diffuser sheet and the light guide plate wherein the light passing through the light-exit face mixes in the light mixing space before going out from the backlight module.

2. The backlight module of claim 1, wherein the light source comprises a point light source.

3. The backlight module of claim 1, wherein the light source comprises a directional light source.

4. The backlight module of claim 3, wherein the light source comprises a double-emitting light source, and the backlight module comprises two of the light guide plates positioned at two sides of the light source for making the light emitted from the light source enter the light guide plates from the light-incidence faces of the light guide plates.

5. The backlight module of claim 1, wherein the light source is positioned in parallel at one side or two sides of the light guide plate.

6. The backlight module of claim 5, wherein the light source comprises red light sources, green light sources, blue light sources or white light sources.

7. The backlight module of claim 1, wherein the light guide plate comprises at least a recessed space to hold the light source.

8. The backlight module of claim 1, further comprising a supporting structure positioned under the light guide plate to hold the light guide plate higher than the light source.

9. The backlight module of claim 8, wherein the supporting structure comprises a reflective element.

10. The backlight module of claim 1, wherein the light-incidence face and the light-exit face of the light guide plate are connected to each other perpendicularly.

11. The backlight module of claim 1, wherein the light-incidence face and the light-exit face of the light guide plate are opposed to each other collaterally.

12. The backlight module of claim 1, wherein the light guide pattern is a V-shaped type or a U-shaped type.

13. The backlight module of claim 1, wherein the light guide patterns comprise printing patterns, sandblasting patterns or dot injection molding patterns to influence total reflection of the light guide plate and to make the light proceed toward the light-exit face.

14. The backlight module of claim 1, further comprising a reflective sheet positioned under the light source and the light guide plate.

15. The backlight module of claim 1, further comprising a frame comprising a containing space to hold the light source, the light guide plate and the diffuser sheet, wherein the portion of the containing space surrounded by the light source, the light guide plate and the diffuser sheet forms the light mixing space.