LED backlighting system

• US 20020140880A1
• Filed: 12/28/2001
• Published: 10/03/2002
• Est. Priority Date: 01/16/2001
• Status: Active Grant

• Current Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Original Assignee: Visteon Global Technologies Incorporated (Visteon Corporation)
• Inventors: Zysnarski, Adam, Weindorf, Paul F.L.
• Granted Patent: US 6,930,737 B2
• Time in Patent Office: Days
• US Class Current: 349/70
• CPC Class Codes: F21Y 2115/10 Light-emitting diodes [LED]
• CPC Class Codes: G02B 6/0023 provided by one optical element, or plurality thereof, placed between the light guide and the light source, or around the light source
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0038 Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide
• CPC Class Codes: G02B 6/0056 for producing polarisation effects, e.g. by a surface with polarizing properties or by an additional polarizing elements
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0083 Details of electrical connections of light sources to drivers, circuit boards, or the like
• CPC Class Codes: G02B 6/0085 Means for removing heat created by the light source from the package heat extraction or cooling elements for semiconductor light sources in general H01L33/64
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133609 including means for improving the color mixing, e.g. white
• CPC Class Codes: G02F 1/133614 using photoluminescence, e.g. phosphors illuminated by UV or blue light
• CPC Class Codes: H05B 45/20 Controlling the colour of the light
• CPC Class Codes: H05B 45/52 in a parallel array of LEDs
• CPC Class Codes: H05B 45/56 involving measures to prevent abnormal temperature of the LEDs

Abstract

A liquid crystal display (LCD) device having non-white and white light emitting diodes and a liquid crystal display. A spectrum converting material is positioned between non-white LEDs and the LCD to convert the non-white light from the LEDs toward a white light spectrum. The liquid crystal display may include a plurality of light emitting diodes, a light pipe, and a spectrum converting material. The spectrum converting material may be a phosphorized material located between the plurality of non-white light emitting diodes and the light pipe. A light extracting surface may be located near a first surface of the light pipe, a diffuser located near a second side of the light pipe, where the first and second sides are opposite sides of the light pipe, a reflective polarizer, and an liquid crystal display. The light from the light pipe may passes through the diffuser, the reflective polarizer, before backlighting the liquid crystal display. The non-white LEDs may include blue LED, ultraviolet LEDs, and the like.

Claims

1. A liquid crystal display (LCD) backlighting backlighting device, comprising:

a non-white light emitting diode;

a liquid crystal display; and

a phosphorized material located between the light emitting diode and the liquid crystal display, where the phosphorized material down converts light from the light emitting diode toward white light spectral radiance.

2. The LCD device of claim 1, wherein the non-white light emitting diode comprises a light emitting diode is selected from the group consisting of blue light emitting diodes and ultraviolet light emitting diodes.

3. The LCD device of claim 1, further comprising a second non-white light emitting diode that differs in color with the non-white light emitting diode comprises a plurality of different colored light emitting diodes.

4. The LCD device of claim 1, wherein the non-white light emitting diode is located along a perimeter of a flexible circuit board.

5. The LCD device of claim 4, wherein the non-white light emitting diode has a top reflective orientation with the light pipe.

6. The LCD device of claim 4, wherein the non-white light emitting diode has a side reflective orientation with the light pipe.

7. The LCD device of claim 1, further comprising a polarization scrambling material between the non-white light emitting diode and the light pipe, where the polarization scrambling material comprises apertures located adjacent to the non-white light emitting diode.

8. The LCD device of claim 1, wherein the phosphorized material comprises a phosphorized rubber.

9. The LCD device of claim 8, wherein the phosphorized material comprises a phosphorized silicone material.

10. The LCD device of claim 1, further comprising:

a light pipe; and

a reflective polarizer;

wherein light from the light pipe passes through the reflective polarizer before backlighting the liquid crystal display.

11. The LCD device of claim 10, wherein the phosphorized material comprises a phosphorized rubber.

12. The LCD device of claim 11, wherein the phosphorized material comprises a phosphorized silicone material.

13. The LCD device of claim 10 further comprising an enhanced specular reflector disposed near the non-white light emitting diode and the light pipe, wherein light from the non-white light emitting diode reflects from the enhanced specular reflector into the light pipe.

14. The LCD device of claim 10, further comprising a polarization scrambling material between the non-white light emitting diode and the light pipe, where the polarization scrambling material comprises apertures located adjacent to the non-white light emitting diode.

15. The LCD device of claim 14, further comprising a second polarization scrambling material located along the light pipe opposite the liquid crystal display.

16. The LCD device of claim 10 further comprising an enhanced diffuser reflector near the light pipe.

17. The LCD device of claim 10, further comprising a diffuser between the light pipe and the reflective polarizer.

18. The LCD device of claim 17, wherein the diffuser comprises a one-sided diffuser.

19. The LCD device of claim 17, further comprising a polarization scrambling material near the diffuser.

20. A liquid crystal display (LCD) device, comprising:

a non-white light emitting diode;

a light pipe;

a spectrum converting material between the non-white light emitting diode and the light pipe;

a light extracting surface located near a first side of the light pipe;

a diffuser located near a second side of the light pipe, where the first and second sides are opposite sides of the light pipe;

a reflective polarizer; and

a liquid crystal display;

wherein light from the non-white light emitting diode and converted by the spectrum converting material enters the light pipe passes through the diffuser, the reflective polarizer, then backlights the liquid crystal display.

21. The LCD device of claim 20, wherein the spectrum converting material comprises a phosphorized material.

22. The LCD device of claim 21, wherein the phosphorized material is disposed adjacent to the light extracting surface.

23. The device of claim 21, wherein the phosphorized material is disposed between the light pipe and reflective polarizer.

24. The LCD device of claim 20, wherein the light emitting diode comprises a top lighting light emitting diode.

25. The LCD device of claim 20, wherein the liquid crystal display comprises an active matrix liquid crystal display.

26. The LCD device of claim 20, wherein the diffuser comprises a phosphor coating.

27. The LCD device of claim 20, wherein the light pipe comprises a phosphor coating.

28. The LCD device of claim 20, wherein the light pipe comprises a phosphor impregnated light pipe.

29. The LCD device of claim 20, wherein the non-white light emitting diode comprises a blue light emitting diode.

30. The LCD device of claim 20, wherein the non-white light emitting diode comprises an ultraviolet light emitting diode.

31. The LCD device of claim 20, wherein the non-white light emitting diode is disposed near an edge of the light pipe.

32. The LCD device of claim 20, wherein the non-white light emitting diode is located along a perimeter of a circuit board.

33. The LCD device of claim 32, wherein the circuit board comprises a flexible circuit board.

34. The LCD device of claim 32, wherein the non-white light emitting diode has a top reflective orientation with an enhanced specular reflector near the end of the light pipe.

35. The LCD device of claim 32, wherein the non-white light emitting diode has a side reflective orientation with an enhanced reflector near the end of the light pipe.

36. The LCD device of claim 20, further comprising a thermally conductive material between the circuit board and a frame.

37. The LCD device of claim 20, further comprising an enhanced diffuser reflector near the light pipe.

38. The LCD device of claim 20, further comprising:

a second non-white light emitting diode that differs in color than the non-white emitting diode,

where the spectrum converting material comprises first and second regions, where the first region converts light from the light emitting diode toward a first white light spectral radiance and the second region converts light from the second light emitting diode toward a second white light spectral radiance.

40. The LCD device of claim 39, wherein the liquid crystal display comprises an active matrix liquid crystal display.

41. The LCD device of claim 39, further comprising an enhanced diffuser reflector near the light pipe.

39. A liquid crystal display (LCD) device, comprising:

a light emitting diode that emits non-white light;

a spectrum converting material;

a diffuser;

a reflective polarizer; and

a liquid crystal display;

wherein light from the light emitting diode is converted by the spectrum converting material before the converted light passes through the diffuser, the reflective polarizer, before backlighting the liquid crystal display.

42. A liquid crystal display, comprising:

a non-white light emitting diode;

a light pipe with a phosphor coating that converts the spectrum of the non-white light emitting diodes and the light pipe;

a light extracting surface located near a first side of the light pipe;

an enhanced diffuser reflector located near an opposite side of the light pipe;

a diffuser located near a second side of the light pipe, where the first and second sides are opposite sides of the light pipe;

a reflective polarizer; and

a liquid crystal display,

wherein light from the light pipe passes through the diffuser, the reflective polarizer, then backlights the liquid crystal display.

43. A liquid crystal display (LCD) device, comprising:

a white light emitting diode;

a light pipe;

a light extracting surface located near a first side of the light pipe;

a diffuser located near a second side of the light pipe, where the first and second sides are opposite sides of the light pipe;

a reflective polarizer; and

a liquid crystal display;

wherein light from the white light emitting diode enters the light pipe and passes through the diffuser, the reflective polarizer, then backlights the liquid crystal display.

44. The LCD device of claim 43, wherein the white light emitting diode is located along a perimeter of a circuit board.

45. The LCD device of claim 44, wherein the circuit board comprises a flexible circuit board.

46. The LCD device of claim 44, further comprising a thermally conductive material between the circuit board and a frame.

47. The LCD device of claim 44, wherein the white light emitting diode has a top reflective orientation with the light pipe.

48. The LCD device of claim 44, wherein the white light emitting diode has a side reflective orientation with the light pipe.

49. The LCD device of claim 43, wherein the diffuser comprises a one-sided diffuser.

50. The LCD device of claim 43, further comprising a polarization scrambling material between the white light emitting diode and the light pipe.

51. The LCD device of claim 50, wherein the polarization scrambling material forms apertures near the white light emitting diode.

52. The LCD device of claim 50, further comprising a second polarization scrambling material located along the light pipe opposite the liquid crystal display.

53. The LCD device of claim 43, further comprising an enhanced diffuser reflector near the light pipe.

54. The LCD device of claim 43, further comprising an enhanced specular reflector disposed near the white light emitting diode and the light pipe, where light form the white light emitting diode reflects from the enhanced specular reflector into the light pipe.