Optical multilayer film and a backlight module utilizing the same

• US 20080062719A1
• Filed: 07/13/2007
• Published: 03/13/2008
• Est. Priority Date: 09/11/2006
• Status: Active Grant

• Current Assignee: Shenzhen China Star Optoelectronics Technology Co., Ltd. (TCL Technology Group Corp.)
• Original Assignee: Coretronic Corporation
• Inventors: Li, Ching-Shiang, Shiau, Tzeng-Ke, Liu, Ming-Dah, Chou, Wen-Bin, Hsaio, Der-Woei
• Granted Patent: US 7,522,802 B2
• Time in Patent Office: Days
• US Class Current: 362/617
• CPC Class Codes: G02B 6/005 provided by one optical element, or plurality thereof, placed on the light output side of the light guide

Abstract

An optical multilayer film includes first and second optical layers, and a refracting layer. The first optical layer has a light-exit surface. The second optical layer has a light-incoming surface facing the light-exit surface of the first optical layer, and a light-outgoing surface opposite to the light-incoming surface and formed with a light-converging structure. The refracting layer is disposed between and is in contact with the first and second optical layers, is made from a transparent material, and has a refractive index that is smaller than that of the second optical layer.

Claims

1. An optical multilayer film comprising:

a first optical layer having a light-exit surface;

a second optical layer having a light-incoming surface facing the light-exit surface of the first optical layer, and a light-outgoing surface opposite to the light-incoming surface and the light-outgoing surface formed with a light-converging structure; and

a refracting layer disposed between and in contact with the first optical layer and the second optical layer, made from a transparent material, and having a refractive index that is smaller than a refractive index of the second optical layer.

2. The optical multilayer film as claimed in claim 1, wherein the refracting layer is made from a transparent resin material.

3. The optical multilayer film as claimed in claim 1, wherein the refractive index of the refracting layer is greater than that of air.

4. The optical multilayer film as claimed in claim 3, wherein the refractive index of the refracting layer is not less than that of the first optical layer.

5. The optical multilayer film as claimed in claim 1, wherein the first optical layer is a diffuser layer for diffusing light beams.

6. The optical multilayer film as claimed in claim 5, wherein the diffuser layer has a plurality of microscopic scattering particles blended therein.

7. The optical multilayer film as claimed in claim 1, wherein the light-converging structure is a prismatic structured array.

8. The optical multilayer film as claimed in claim 1, wherein the first optical layer is a diffuser layer, and the second optical layer is a brightness enhancement layer.

9. A backlight module comprising:

a reflector having a reflective surface;

at least one light source unit disposed in a space defined by the reflector; and

an optical multilayer film disposed over the reflector, and including;

a first optical layer having a light-incident surface facing the light source unit, and a light-exit surface opposite to the light-incident surface;

a second optical layer having a light-incoming surface facing the light-exit surface of the first optical layer, and a light-outgoing surface opposite to the light-incoming surface and the light-outgoing surface formed with a light-converging structure; and

a refracting layer disposed between and in contact with the first and second optical layers, made from a transparent material, and having a refractive index that is smaller than a refractive index of the second optical layer.

10. The backlight module as claimed in claim 9, wherein the refracting layer of the optical multilayer film is made from a transparent resin material.

11. The backlight module as claimed in claim 9, wherein the refractive index of the refracting layer of the optical multilayer film is greater than that of air.

12. The backlight module as claimed in claim 11, wherein the refractive index of the refracting layer of the optical multilayer film is not less than that of the first optical layer.

13. The backlight module as claimed in claim 9, wherein the first optical layer of the optical multilayer film is a diffuser layer for diffusing light beams.

14. The backlight module as claimed in claim 13, wherein the diffuser layer has a plurality of microscopic scattering particles blended therein.

15. The backlight module as claimed in claim 9, wherein the light-converging structure of the light-outgoing surface of the second optical layer of the optical multilayer film is a prismatic structured array.

16. The backlight module as claimed in claim 9, wherein the light source unit is a cold cathode fluorescent lamp unit.

17. The backlight module as claimed in claim 9, wherein the light source unit is a light emitting diode lamp unit.

18. The backlight module as claimed in claim 9, wherein the first optical layer of the optical multilayer film is a diffuser layer, and the second optical layer is a brightness enhancement layer.