Backlight unit of liquid crystal display

• US 20030117790A1
• Filed: 12/13/2002
• Published: 06/26/2003
• Est. Priority Date: 12/21/2001
• Status: Abandoned Application

• Current Assignee: AU Optronics Corporation
• Original Assignee: AU Optronics Corporation
• Inventors: Lee, Ching-Ping, Tang, Nai-Yuan
• Application Number:
  US10/318,134
• Publication Number:
  US 20030117790A1
• Time in Patent Office: Days
• US Class Current: 362/31
• CPC Class Codes: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity

Abstract

A backlight unit for enhancing brightness of a TFT-LCD device is disclosed. The backlight unit comprises a lamp and a light guide plate. The light guide plate has a top surface and one side. And the lamp is fastened to the side of the light guide plate for illumination. The light is multiple reflected in the light guide plate and emitted from the top surface of the light guide plate. The backlight unit further comprises an optical film and an adhesive layer, wherein the optical film is disposed on the light guide plate to spread the light uniformly, and the adhesive layer is applied to fill gaps between the light guide plate and the optical film. The adhesive layer has a refractive index equal to that of the light guide plate and the optical film for decreasing multiple reflections therebetween.

Claims

1. A backlight unit for enhancing brightness of a TFT-LCD device comprises of:

a lamp for providing a light;

a light guide plate having a top surface and one side, wherein said light is multiple reflected in said light guide plate and emitted from said top surface of said light guide plate, said lamp is fastened to said side of said light guide plate to illuminate said light into said light guide plate with an edgelight form;

an optical film disposed on said light guide plate to spread uniformly said light emitted from said light guide plate; and

an adhesive layer disposed between said light guide plate and said optical film to fill gaps between said light guide plate and said optical film to prevent said light from multiple reflections between said light guide plate and said optical film.

2. The backlight unit of claim 1, wherein a refractive index of said adhesive layer is equal to that of said light guide plate and said optical film.

3. The backlight unit of claim 1, wherein said optical film comprises an upper diffuser, a brightness enhanced film and a lower diffuser.

4. The backlight unit of claim 3, wherein said brightness enhanced film can be chosen from a prizm, a polarizer, or any combination thereof.

5. The backlight unit of claim 1, wherein said optical film comprises a diffuser.

6. The backlight unit of claim 5, wherein refractive index of said diffuser and said light guide plate are both about 1.4˜

1.6, and a refractive index of said adhesive layer is about 1.4˜

1.6 to prevent said light from multiple reflections between said light guide plate and said diffuser.

7. The backlight unit of claim 1, wherein said optical film comprises a brightness enhanced film.

8. The backlight unit of claim 7, wherein said brightness enhanced film can be chosen from a prizm, a polarizer or any combination thereof.

9. The backlight unit of claim 7, wherein refractive index of said diffuser and said light guide plate are both about 1.4˜

1.6, and a refractive index of said adhesive layer is about 1.4˜

1.6 to prevent said light from multiple reflections between said light guide plate and said diffuser.

10. The backlight unit of claim 1, wherein said adhesive layer has micro-particles doped therein to diffuse said light.

11. The backlight unit of claim 1, wherein a reflector cover encompassing said lamp has an opening towards said light guide plate, and illuminations of said lamp are reflected and gathered by said reflector cover and transmitted into said light guide plate through said open.

12. The backlight unit of claim 1, further comprising a reflector plate mounted beneath said light guide plate to reflect lights emitted from a lower surface of said light guide plate.

13. A backlight unit for enhancing brightness of a TFT-LCD device comprises of:

a lamp for providing a light;

a light guide plate having a top surface, wherein said light is multiple reflected in said light guide plate and emitted from said top surface thereof, said lamp is disposed beneath said light guide plate to illuminate said light into said light guide plate with an backlight form;

an optical film disposed on said light guide plate to spread said light emitted from said light guide plate uniformly; and

an adhesive layer disposed between said light guide plate and said optical film to fill gaps therebetween to reduce multiple reflections of said light between said light guide plate and said optical film.

14. The backlight unit of claim 13, wherein a refractive index of said adhesive layer is equal to that of said light guide plate and said optical film to prevent said light from multiple reflections between said light guide plate and said optical film.

15. The backlight unit of claim 13, wherein said optical film comprises a diffuser.

16. The backlight unit of claim 15, wherein refractive index of said diffuser and said light guide plate are both about 1.4˜

1.6, and a refractive index of said adhesive layer is about 1.4˜

1.6 to prevent said light from multiple reflections between said light guide plate and said diffuser.

17. The backlight unit of claim 13, wherein said optical film comprises a brightness enhanced film.

18. The backlight unit of claim 17, wherein refractive index of said diffuser and said light guide plate are both about 1.4˜

1.6, and a refractive index of said adhesive layer is about 1.4˜

1.6 to prevent said light from multiple reflections between said light guide plate and said diffuser.

19. The backlight unit of claim 13, wherein said adhesive layer has micro-particles doped therein to diffuse said light.

20. The backlight unit of claim 13, further comprising a reflector plate mounted beneath said light guide plate to reflect lights emitted from a lower surface of said light guide plate.