Light emitting diode backlight unit and liquid crystal display having the same

• US 20070223248A1
• Filed: 09/21/2006
• Published: 09/27/2007
• Est. Priority Date: 03/27/2006
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Philips LCD Company Limited (LG Display Co., Ltd.)
• Inventors: Han, Jeong Hun
• Granted Patent: US 7,481,566 B2
• Time in Patent Office: Days
• US Class Current: 362/612
• CPC Class Codes: G02B 6/0025 Diffusing sheet or layer; Prismatic sheet or layer
• CPC Class Codes: G02B 6/0028 Light guide, e.g. taper
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources

Abstract

A backlight unit and a liquid crystal display having the backlight are provided. The backlight unit includes a plurality of light emitting diode (LED) chips, a light guide plate for converting light generated from the LED chips into surface light, and a plurality of optical guide modules corresponding to the respective LED chips and disposed between the LED chips and the light guide plate.

Claims

1. A backlight unit comprising:

a plurality of light emitting diode (LED) chips;

a light guide plate operative to convert light generated from the LED chips into surface light; and

a plurality of optical guide modules corresponding to the respective LED chips and disposed between the plurality of LED chips and the light guide plate, wherein the plurality of optical guide modules further comprise at least one of a light scattering unit and a plurality of plates.

2. The backlight unit of claim 1, wherein each of the plurality of LED chips comprises red, green and blue LEDs.

3. The backlight unit of claim 1, wherein each of the plurality of LED chips comprises a white LED.

4. The backlight unit of claim 1, wherein the plurality of LED chips are mounted on a circuit board at determined intervals.

5. The backlight unit of claim 1, wherein the plurality of plates comprises a plurality of louver plates.

6. The backlight unit of claim 5, wherein the plurality of light scattering elements comprises a plurality of slits.

7. The backlight unit of claim 6, wherein the plurality of slits have a bar shape with a triangular cross-section.

8. The backlight unit of claim 7, wherein the plurality of slits are disposed in front of the plurality of LED chips.

9. The backlight unit of claim 6, wherein the plurality of louver plates are symmetrically disposed with reference to the plurality of slits.

10. The backlight unit of claim 5, wherein the plurality of louver plates are inclined at a determined angle with reference to a centerline of an LED chip of the plurality of LED chips.

11. The backlight unit of claim 5, wherein each of the plurality of louver plates have different lengths from each other.

12. The backlight unit of claim 6, wherein distances between the slits disposed at an area corresponding to the plurality of LED chips are less than those between the plurality of slits disposed at other areas.

13. The backlight unit of claim 1, further comprising a reflective unit formed on the circuit board between the plurality of LED chips.

14. A backlight unit comprising:

a plurality of light emitting diode (LED) chips;

a light guide plate operative to convert light generated from the LED chips into surface light; and

a plurality of optical guide modules corresponding to the respective LED chips and disposed between the plurality of LED chips and the light guide plate, wherein the plurality of optical guide modules further comprise a plurality of light scattering elements and a plurality of plates.

15. The backlight unit of claim 14, wherein each of the plurality of LED chips comprises red, green and blue LEDs.

16. The backlight unit of claim 14, wherein each of the plurality of LED chips comprises a white LED.

17. The backlight unit of claim 14, wherein the plurality of LED chips are mounted on a circuit board at determined intervals.

18. The backlight unit of claim 14, wherein the plurality of plates comprises a plurality of louver plates.

19. The backlight unit of claim 18, wherein the plurality of light scattering elements comprises a plurality of slits.

20. The backlight unit of claim 19, wherein the plurality of slits have a bar shape with a triangular cross-section.

21. The backlight unit of claim 20, wherein the plurality of slits are disposed in front of the plurality of LED chips.

22. The backlight unit of claim 19, wherein the plurality of louver plates are symmetrically disposed with reference to the plurality of slits.

23. The backlight unit of claim 18, wherein the plurality of louver plates are inclined at a determined angle with reference to a centerline of an LED chip of the plurality of LED chips.

24. The backlight unit of claim 18, wherein each of the plurality of louver plates have different lengths from each other.

25. The backlight unit of claim 18, wherein distances between the slits disposed at an area corresponding to the plurality of LED chips are less than those between the plurality of slits disposed at other areas.

26. The backlight unit of claim 15, further comprising a reflective unit formed on the circuit board between the plurality of LED chips.

27. The backlight unit of claim 19, wherein the plurality of louver plates are symmetrically disposed with reference to the plurality of slits.

28. A backlight unit comprising:

a plurality of light emitting diode (LED) chips;

a light guide plate operative to convert light generated from the LED chips into surface light; and

a plurality of optical guide modules corresponding to the respective LED chips and disposed between the plurality of LED chips and the light guide plate, wherein the plurality of optical guide modules further comprise a plurality of light scattering elements formed on a plate.

29. The backlight unit of claim 28, wherein each of the plurality of LED chips comprises red, green and blue LEDs.

30. The backlight unit of claim 28, wherein each of the plurality of LED chips comprises a white LED.

31. The backlight unit of claim 28, wherein the plurality of LED chips are mounted on a circuit board at determined intervals.

32. The backlight unit of claim 28, wherein the plurality of light scattering elements comprises a plurality of slits.

33. The backlight unit of claim 32, wherein the plurality of slits have a bar shape with a triangular cross-section.

34. The backlight unit of claim 33, wherein the plurality of slits are disposed in front of the plurality of LED chips.

35. The backlight unit of claim 32, wherein distances between the slits disposed at an area corresponding to the plurality of LED chips are less than those between the plurality of slits disposed at other areas.

36. The backlight unit of claim 28, further comprising a reflective unit formed on the circuit board between the plurality of LED chips.

37. A backlight unit comprising:

a plurality of light emitting diode (LED) chips;

a light guide plate operative to convert light generated from the LED chips into surface light; and

a plurality of optical guide modules corresponding to the respective LED chips and disposed between the plurality of LED chips and the light guide plate, wherein the plurality of optical guide modules further comprises a plurality of louver plates formed between each of the plurality of LED chips, wherein the plurality of louver plates are disposed between an upper plate and a lower plate.

38. The backlight unit of claim 37, wherein each of the plurality of LED chips comprises red, green and blue LEDs.

39. The backlight unit of claim 37, wherein each of the plurality of LED chips comprises a white LED.

40. The backlight unit of claim 37, wherein the plurality of LED chips are mounted on a circuit board at determined intervals.

41. The backlight unit of claim 37, wherein the plurality of louver plates are inclined at a determined angle with reference to a centerline of an LED chip of the plurality of LED chips.

42. The backlight unit of claim 37, wherein each of the plurality of louver plates have different lengths from each other.

43. The backlight unit of claim 37, further comprising a reflective unit formed on the circuit board between the plurality of LED chips.

44. A liquid crystal display device comprising:

an LCD display panel;

a plurality of light emitting diode (LED) chips;

a light guide plate operative to convert light generated from the LED chips into surface light; and

a plurality of optical guide modules corresponding to the respective LED chips and disposed between the plurality of LED chips and the light guide plate, wherein the plurality of optical guide modules further comprise at least one of a plurality of light scattering elements and a plurality of plates.

45. The backlight unit of claim 44, wherein each of the plurality of LED chips comprises red, green and blue LEDs.

46. The backlight unit of claim 44, wherein each of the plurality of LED chips comprises a white LED.

47. The backlight unit of claim 44, wherein the plurality of LED chips are mounted on a circuit board at determined intervals.

48. The backlight unit of claim 44, wherein the plurality of light scattering elements comprises a plate and a plurality of slits.

49. The backlight unit of claim 48, wherein the plurality of slits have a bar shape with a triangular cross-section.

50. The backlight unit of claim 49, wherein the plurality of slits are disposed in front of the plurality of LED chips.

51. The backlight unit of claim 48, wherein distances between the slits disposed at an area corresponding to the plurality of LED chips are less than those between the plurality of slits disposed at other areas.

52. The backlight unit of claim 44, further comprising a reflective unit formed on the circuit board between the plurality of LED chips.

53. A method of display in a liquid crystal device, the liquid crystal device comprising a plurality of light emitting diode (LED) chips, a light guide plate operative to convert light generated from the LED chips into surface light, and a plurality of optical guide modules corresponding to the respective LED chips and disposed between the plurality of LED chips and the light guide plate, the method comprising:

arranging a circuit board operative to supply electric power to the plurality of LED chips at a light incident area of the light guide plate;

mounting the plurality of LED chips on the circuit board at determined intervals;

arranging the plurality of optical guide modules to enclose respective LED chips of the plurality of LED chips, wherein the plurality of optical guide modules include at least one of a plurality of light scattering elements and a plurality of plates.

54. The method of claim 53, wherein the plurality of optical guide modules further comprise a plurality of slits and a plurality of louver plates, the method further comprising:

arranging the plurality of slits in front of the plurality of LED chips; and

symmetrically arranging the plurality of louver plates with reference to the plurality of slits.

55. The method of claim 54, further comprising inclining the plurality of louver plates at a determined angle with reference to a centerline of an LED chip of the plurality of LED chips.