IP Library Granted Patent US 7,377,681
Granted Patent B2
US 7,377,681 · App. 11/280,732 · Granted May 27, 2008

Backlight unit and liquid crystal display device having the same

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Quick Facts
Patent No.
US 7,377,681
App. No.
11/280,732
Granted
May 27, 2008
Kind
B2
Abstract

A backlight unit for a liquid crystal display device includes a first light-emitting unit having first and second passive light-emitting lamps; a second light-emitting unit having a plurality of self light-emitting lamps; and a light guide disposed between the first and second light-emitting units guiding an incident light from the second light-emitting unit to the first light-emitting unit.

Claims (47)

1. A backlight unit for a liquid crystal display device, comprising:

a first light-emitting unit having first and second passive light-emitting lamps;

a second light-emitting unit having a plurality of self light-emitting lamps; and

a light guide disposed between the first and second light-emitting units such that most of a light incident onto the light guide from the second light-emitting unit is transmitted to the first light-emitting unit through a whole area of the light guide;

wherein the self light-emitting lamps are disposed between the first and second passive light-emitting lamps.

2. The backlight unit of claim 1 , further comprising a diverter disposed at a first side of each of the self light-emitting lamps for laterally scattering light incident from the self light-emitting lamps.

3. The backlight unit of claim 2 , further including a reflector disposed at a second side of the self light-emitting lamps for reflecting light incident from the self-emitting lamps toward the light guide.

4. The backlight unit of claim 3 , further including a light scattering part provided above the first and second passive light-emitting lamps.

5. The backlight unit of claim 4 , wherein each of the first and second passive light-emitting lamps includes a cold cathode fluorescent lamp.

6. The backlight unit of claim 4 , wherein each of the first and second passive light-emitting lamps includes a hot cathode fluorescent lamp.

7. The backlight unit of claim 4 , wherein each of the self light-emitting lamps includes an electroluminescence lamp.

8. The backlight unit of claim 4 , wherein each of the self light-emitting lamps includes a light-emitting diode.

9. The backlight unit of claim 2 , wherein the diverter is disposed on a second surface of the light guide means.

10. The backlight unit of claim 2 , wherein the diverter is disposed on a first surface of the light guide.

11. The backlight unit of claim 2 , wherein the diverter includes a second diverter disposed on a second surface of the light guide and a first diverter disposed on a first surface of the light guide.

12. A backlight unit for an LCD device, comprising:

a first light-emitting unit having a plurality of passive light-emitting lamps;

a second light-emitting unit provided at a lower side of the first light-emitting unit and having a plurality of self light-emitting lamps;

a light guide plate interposed between the first and second light-emitting units such that most of a light incident onto the light guide plate from the second light-emitting unit is transmitted to the first light-emitting unit through a whole area of the light guide plate;

a reflection plate provided at a lower side of the second light-emitting unit; and

a light scattering unit provided at a second side of the first light-emitting unit;

wherein the self light-emitting lamps are disposed between the first and second passive light-emitting lamps.

13. The backlight unit of claim 12 , wherein each of the passive light-emitting lamps includes one of a cold cathode fluorescent lamp or a hot cathode fluorescent lamp.

14. The backlight unit of claim 12 , wherein each of the self light-emitting lamps includes one of an electro-luminescence lamp or a light-emitting diode.

15. The backlight unit of claim 12 , further comprising a plurality of diverters, each diverter disposed at a first portion of a corresponding one of the self light-emitting lamps, the diverters for laterally scattering vertically incident light toward the light guide plate.

16. The backlight unit of claim 15 , wherein the diverters are formed on a first surface of the light guide plate.

17. The backlight unit of claim 15 , wherein the diverters are formed on a second surface of the light guide plate.

18. The backlight unit of claim 15 , wherein the diverters are formed on the first surface and the second surface of the light guide plate.

19. The backlight of claim 12 , wherein the light guide plate is made of one of a poly methyl meth-acrylate, a glass substrate, or a poly-carbonate.

20. The backlight unit of claim 12 , wherein the light scattering unit includes:

a diffusion plate for distributing light incident from the first and second light-emitting units;

a prism sheet for enhancing a front surface luminance of light reflected after being transmitted to a first portion of the diffusion plate; and

a protection sheet disposed on a first portion of the prism sheet.

21. A liquid crystal display device, comprising a liquid crystal panel and a backlight unit for supplying light to the liquid crystal panel, wherein the backlight unit comprises:

a first light-emitting unit having a plurality of passive light-emitting lamps;

a second light-emitting unit provided at a first side of the first light-emitting unit and having a plurality of self light-emitting lamps;

a light guide plate interposed between the first and second light-emitting units such that most of a light incident onto the light guide plate from the second light-emitting unit is transmitted to the first light-emitting unit through a whole area of the light guide plate;

a reflection plate provided at a first side of the second light-emitting unit; and

a light scattering unit provided at a second side of the first light-emitting unit;

wherein the self light-emitting lamps are disposed between the first and second passive light-emitting lamps.

22. The liquid crystal display device of claim 21 , wherein each of the passive light-emitting lamps includes one of a cold cathode fluorescent lamp or a hot cathode fluorescent lamp.

23. The liquid crystal display device of claim 21 , wherein each of the self light-emitting lamps includes one of an electro-luminescence lamp or a light-emitting diode.

24. A backlight unit for an LCD device, comprising:

a first light-emitting unit having a plurality of passive light-emitting lamps;

a second light-emitting unit having a plurality of self light-emitting lamps disposed between the passive light-emitting lamps;

a light guide plate interposed between the first and second light-emitting units for transmitting most of a light incident thereto from the second light-emitting unit to the first light-emitting unit through a whole area of the light guide plate; and

a plurality of diverters on a surface of the light guide plate, each diverter directly facing a corresponding one of the self light-emitting lamps, the diverters for laterally scattering vertically incident light toward the light guide plate.

Assignments (2)
CHANGE OF NAME Recorded Oct 27, 2008
From: LG.PHILIPS LCD CO., LTD.
To: LG DISPLAY CO., LTD.
Reel/Frame 021772/0701 →
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Nov 17, 2005
From: PARK, HEE-JEONG
To: LG.PHILIPS LCD CO., LTD.
Reel/Frame 017259/0095 →