BACKLIGHT UNIT AND LIQUID CRYSTAL DISPLAY DEVICE HAVING THE SAME

• US 20090180055A1
• Filed: 11/12/2008
• Published: 07/16/2009
• Est. Priority Date: 01/15/2008
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: JANG, Eun-joo, PARK, Hae-il, LIM, Jung-eun, KIM, Byung-ki
• Granted Patent: US 8,035,772 B2
• Time in Patent Office: Days
• US Class Current: 349/69
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: Y10S 977/952 Display

Abstract

A backlight unit for a liquid crystal display (“LCD”) device includes a light emitting diode (“LED”) light source and a light conversion layer disposed separate from and above from the LED light source. The light conversion layer includes a semiconductor nano crystal, converts light emitted from the LED light source to white light and provides the white light to a liquid crystal panel of the LCD.

Claims

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

a light emitting diode light source; and

a light conversion layer disposed separate from the light emitting diode light source between the liquid crystal panel and the light emitting diode light source, wherein

the light conversion layer comprises a semiconductor nano crystal, and

the light conversion layer converts light emitted from the light emitting diode light source to white light and provides the white light to the liquid crystal panel.

2. The backlight unit of claim 1, further comprising one of a diffusion panel disposed between the light conversion layer and the liquid crystal panel and a diffusion panel disposed between the light emitting diode light source and the light conversion layer.

3. The backlight unit of claim 1, wherein the light conversion layer is manufactured by coating the semiconductor nano crystal onto a transparent substrate.

4. The backlight unit of claim 1, wherein the light conversion layer is manufactured by distributing the semiconductor nano crystal in a film type material and distributing the film type material into a transparent composite.

5. The backlight unit of claim 2, wherein the light conversion layer is manufactured by coating the semiconductor nano crystal onto the diffusion panel.

6. The backlight unit of claim 1, wherein the light conversion layer comprises a plurality of layers.

7. The backlight unit of claim 6, wherein the plurality of layers are disposed such that a layer has a light emission wavelength having a lower energy as the layer is located closer to the LED light source.

8. The backlight unit of claim 6, wherein the plurality of layers are separated from one another and a blank layer is formed therebetween.

9. The backlight unit of claim 1, wherein the light emitting diode light source is disposed at a side of the light conversion layer.

10. The backlight unit of claim 9, further comprising a light guide panel disposed between the light emitting diode light source and the light conversion layer, wherein the light guide panel guides the light emitted from the light emitting diode light source to the light conversion layer.

11. The backlight unit of claim 1, wherein the light emitting diode light source emits one of a blue light and an ultraviolet light.

12. A liquid crystal display device comprising:

a light emitting diode light source;

a light conversion layer disposed separate from and above the light emitting diode light source; and

a liquid crystal panel disposed above the light conversion layer, wherein

the light conversion layer comprises a semiconductor nano crystal,

the light conversion layer converts light emitted from the light emitting diode light source to white light, and

the liquid crystal panel forms an image using the white light.

13. The liquid crystal display device of claim 12, further comprising one of a diffusion panel disposed between the light conversion layer and the liquid crystal panel and a diffusion panel disposed between the light emitting diode light source and the light conversion layer.

14. The liquid crystal display device of claim 12, wherein the light emitting diode light source is disposed at a peripheral side of the light conversion layer.

15. The liquid crystal display device of claim 12, wherein the light emitting diode light source emits one of a blue light and an ultraviolet light.

16. The liquid crystal display device of claim 12, wherein the liquid crystal panel comprises:

a liquid crystal layer; and

a color filter disposed adjacent to the liquid crystal layer, wherein the color filter receives the white light and forms an image having a predetermined color using the white light.

17. A backlight unit for a liquid crystal display device including a liquid crystal panel, the backlight unit comprising:

a light emitting diode light source; and

a light conversion diffusion layer disposed separate from the light emitting diode light source between the liquid crystal panel and the light emitting diode light source, wherein

the light conversion diffusion layer comprises a semiconductor nano crystal, and

the light conversion diffusion layer converts light emitted from the light emitting diode light source to white light and provides the white light to the liquid crystal panel.

18. The backlight unit of claim 17, wherein the light conversion diffusion layer is manufactured by distributing the semiconductor nano crystal in a film type material in a transparent composite including a light diffusion material.

19. The backlight unit of claim 17, wherein the light emitting diode light source is disposed at a peripheral side of the light conversion diffusion layer.

20. The backlight unit of claim 19, further comprising a light guide panel disposed between the light emitting diode light source and the light conversion diffusion layer, wherein the light guide panel guides the light emitted from the light emitting diode light source to the light conversion diffusion layer.

21. The backlight unit of claim 17, wherein the light conversion diffusion layer comprises a plurality of layers.

22. The backlight unit of claim 21, wherein the plurality of layers are disposed such that a layer has a light emission wavelength having a lower energy as the layer is located closer to the LED light source.

23. The backlight unit of claim 21, wherein the plurality of layers are separated from one another and a blank layer is formed therebetween.

24. A liquid crystal display device comprising:

a light emitting diode light source;

a light conversion diffusion layer disposed separate from and above the light emitting diode light source; and

a liquid crystal panel disposed above the light conversion diffusion layer, wherein

the light conversion diffusion layer comprises a semiconductor nano crystal,

the light conversion diffusion layer converts light emitted from the light emitting diode light source to white light, and

the liquid crystal panel forms an image using the white light.

25. The liquid crystal display device of claim 24, wherein the light emitting diode light source is disposed at a peripheral side of the light conversion diffusion layer.

26. The liquid crystal display device of claim 24, wherein the light emitting diode light source emits one of a blue light and an ultraviolet light.