Backlight module and brightness enhancement film thereof

• US 7,290,919 B2
• Filed: 04/21/2006
• Issued: 11/06/2007
• Est. Priority Date: 11/25/2005
• Status: Active Grant

• Current Assignee: AU Optronics Corporation, Sun Yat-Sen University
• Original Assignee: AU Optronics Corporation, Sun Yat-Sen University
• Inventors: Cheng, Han-chang, Su, Ching-hua, Pan, Cheng-tang, Pan, Chih-liang
• Primary Examiner(s): Husar; Stephen F.
• Assistant Examiner(s): Dunwiddie; Meghan K.
• Application Number:
  US11/409,302
• Publication Number:
  US 20070121339A1
• Time in Patent Office: 564 Days
• Field of Search: 362/606, 362/609, 362/615, 362/618, 362619-621
• US Class Current: 362/618
• CPC Class Codes: G02B 3/0018 Reflow, i.e. characterized by the step of melting microstructures to form curved surfaces, e.g. manufacturing of moulds and surfaces for transfer etching
• CPC Class Codes: G02B 3/0056 arranged along two different directions in a plane, e.g. honeycomb arrangement of lenses G02B3/0043 takes precedence; miniaturised objectives for electronic devices employing wafer level optics G02B13/0085
• CPC Class Codes: G02B 6/0053 Prismatic sheet or layer; Brightness enhancement element, sheet or layer

Abstract

A backlight module includes a light source, a light guide plate for guiding light from the light source, and a brightness enhancement film having a plurality of spherical surface microlenses for gathering light from the light guide plate. In contrast to traditional prism sheets, the brightness enhancement film having the plurality of spherical surface microlenses have better efficiency of light-gathering.

Claims

1. A backlight module, comprising:

a light source;

a light guide plate for guiding light from the light source; and

a brightness enhancement film, having a plurality of spherical surface microlenses and a plurality of carriers formed thereon, disposed over the light guide plate, wherein each of the spherical surface microlenses is disposed on the corresponding one of the plurality of carriers, thereby increasing a height-wide ratio of the brightness enhancement film.

2. The backlight module of claim 1, further comprising a reflector for reflecting light from the light source.

3. The backlight module of claim 1, wherein the plurality of carriers are substantially shaped as triangles, rectangles or hexagons.

4. The backlight module of claim 1, wherein each of the plurality of carriers is closely disposed with each other.

5. The backlight module of claim 1, further comprising a diffuser disposed between the light guide plate and the brightness enhancement film.

6. The backlight module of claim 1, further comprising a diffuser disposed over the brightness enhancement film.

7. The backlight module of claim 1, wherein the plurality of microlenses are made of polyester or polycarbonate.

8. A liquid crystal display comprising the backlight module of claim 1.

9. A brightness enhancement film, comprising:

a substrate;

a plurality of first carriers disposed on the substrate; and

a plurality of spherical surface microlenses, each being disposed on the corresponding one of the plurality of first carriers.

10. The brightness enhancement film of claim 9, wherein the plurality of first carriers are substantially shaped as triangles, rectangles or hexagons.

11. The brightness enhancement film of claim 9, wherein each of the plurality of first carriers is closely disposed with each other.

12. The brightness enhancement film of claim 9, wherein the plurality of microlenses are made of polyester or polycarbonate.

13. The brightness enhancement film of claim 9, further comprising a plurality of second carriers, wherein the plurality of first carriers are disposed on the plurality of second carriers, thereby increasing a height-wide ratio of the brightness enhancement film.

14. A backlight module, comprising:

a light source;

a light guide plate for guiding light from the light source; and

a brightness enhancement film, having a plurality of spherical surface microlenses and a plurality of carriers formed thereon, disposed over the light guide plate, wherein each of the plurality of carriers is closely disposed with each other, and each of the spherical surface microlenses is disposed on the corresponding one of the plurality of carriers.

15. The backlight module of claim 14, further comprising a reflector for reflecting light from the light source.

16. The backlight module of claim 14, wherein the plurality of carriers are substantially shaped as triangles, rectangles or hexagons.

17. The backlight module of claim 14, further comprising a diffuser disposed between the light guide plate and the brightness enhancement film.

18. The backlight module of claim 14, further comprising a diffuser disposed over the brightness enhancement film.

19. The backlight module of claim 14, wherein the plurality of microlenses are made of polyester or polycarbonate material.