Backlight module

• US 8,408,776 B2
• Filed: 11/12/2009
• Issued: 04/02/2013
• 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:
  US12/616,791
• Publication Number:
  US 20100061116A1
• Time in Patent Office: 1,237 Days
• Field of Search: 349/65, 362612-614, 362/616, 362/26, 362/27, 362/606, 362/607, 385/129, 385/901
• US Class Current: 362/616
• 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 being emitted out of the backlight module.

Claims

1. A backlight module comprising:

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

a second light guide plate positioned adjacent to the first light guide plate, the second light guide plate having a second light-exit face and at least one second light-incidence face;

a double-emitting light source positioned between the first light guide plate and the second light guide plate, wherein light emitted from the double-emitting light source enters the first light guide plate from the first light-incidence face and enters the second light guide plate from the second light-incidence face;

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

a light mixing space disposed between the diffuser sheet and the first light guide plate, and between the diffuser sheet and the second light guide plate, wherein the light passing through the first light-exit face and the second light-exit face mixes in the light mixing space before being emitted from the backlight module.

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

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

4. The backlight module of claim 1, wherein the first light guide plate and the second light guide plate are strip-shaped to make the light passing through the first light guide plate and the second light guide plate become a line-like source.

5. The backlight module of claim 1, wherein the first light guide plate and the second light guide plate comprise a plurality of light guide patterns respectively for guiding the light toward the first light-exit face and the second light-exit face.

6. The backlight module of claim 5, wherein the light guide patterns are positioned on a part of the first light guide plate to make light passing through the first light-exit face become a plurality of line-like sources.

7. The backlight module of claim 5, wherein each of the light guide patterns is a V-shaped type or a U-shaped type.

8. The backlight module of claim 5, wherein the light guide patterns comprise printing patterns, sandblasting patterns or dot injection molding patterns to influence total reflection of the first light guide plate and to make the light proceed toward the first light-exit face.

9. The backlight module of claim 1, further comprising a reflective sheet positioned under the double-emitting light source, the first light guide plate and the second light guide plate.

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