Light guiding plate, backlight assembly having the same, and display device having the same

• US 20060279672A1
• Filed: 06/14/2006
• Published: 12/14/2006
• Est. Priority Date: 06/14/2005
• Status: Active Grant

• Current Assignee: Samsung Display Company Limited (Samsung Electronics Co. Ltd.)
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Kim, Joong-Hyun, Hwang, In-Sun
• Granted Patent: US 7,847,880 B2
• Time in Patent Office: Days
• US Class Current: 349/65
• CPC Class Codes: G02F 1/13362 providing polarized light, e.g. by converting a polarisation component into another one

Abstract

A light guiding plate, a backlight assembly having the light guiding plate and a display device having the backlight assembly include a light guiding plate body, a polarization transformation layer on a surface of the light guiding plate body to transform a polarization component of light emitted through the light guiding plate, and a polarization extraction layer on the polarization transformation layer.

Claims

1. A light guiding plate comprising:

a light guiding plate body;

a polarization transformation layer on a surface of the light guiding plate body to transform a polarization component of light emitted through the light guiding plate; and

a polarization extraction layer on the polarization transformation layer.

2. The light guiding plate of claim 1, wherein the polarization transformation layer transforms a P polarization component into a sum of P and S polarization components.

3. The light guiding plate of claim 1, wherein the polarization transformation layer allows the light to be subject to birefringence.

4. The light guiding plate of claim 1, wherein the polarization transformation layer is a retardation film.

5. The light guiding plate of claim 4, wherein the retardation film includes at least one resin selected from a group consisting of poly ethylene terephthalate (PET) and poly ethylene naphthalate (PEN).

6. The light guiding plate of claim 1, wherein a plurality of refractive members are disposed on the surface of the light guiding plate body to be separated from each other and extend in a predetermined direction.

7. The light guiding plate of claim 6, wherein a height of each of the refractive members is in a range from about 5 μ

m to about 12 μ

m.

8. The light guiding plate of claim 6, wherein a vertex angle of each of the refractive members is in a range from about 30°

to about 70°

.

9. The light guiding plate of claim 6, wherein a pitch of each of the refractive members is in a range from about 10 μ

m to about 100 μ

m.

10. The light guiding plate of claim 6, wherein the height of each of the refractive members is larger than a thickness of the polarization extraction layer.

11. The light guiding plate of claim 1, wherein the polarization transformation layer has a plurality of refractive indexes varying according to direction.

12. The light guiding plate of claim 1, wherein the polarization extraction layer includes a plurality of liquid crystal polymers (LCP).

13. The light guiding plate of claim 1, wherein the polarization transformation layer passes only an S polarization component.

14. The light guiding plate of claim 1, further comprising a protective layer which is stacked on the polarization extraction layer to protect the polarization extraction layer.

15. A backlight assembly comprising:

a light source; and

a light guiding plate for guiding light emitted from the light source,

wherein the light guiding plate comprises;

a light guiding plate body;

a polarization transformation layer on a surface of the light guiding plate body to transform a polarization component of light emitted through the light guiding plate; and

a polarization extraction layer on the polarization transformation layer.

16. The backlight assembly of claim 15, wherein the polarization transformation layer transforms a P polarization component into a sum of P and S polarization components.

17. The backlight assembly of claim 15, wherein the polarization transformation layer allows the light to be subject to birefringence.

18. The backlight assembly of claim 15, wherein the polarization transformation layer is a retardation film.

19. The backlight assembly of claim 18, wherein the retardation film includes at least one resin selected from a group consisting of poly ethylene terephthalate (PET) and poly ethylene naphthalate (PEN).

20. The backlight assembly of claim 15, wherein a plurality of refractive members are disposed on the surface of the light guiding plate body to be separated from each other and extend in a predetermined direction.

21. The backlight assembly of claim 20, wherein a height of each of the refractive members is in a range from about 5 μ

m to about 12 μ

m.

22. The backlight assembly of claim 20, wherein a vertex angle of each of the refractive members is in a range from about 30°

to about 70°

.

23. The backlight assembly of claim 20, wherein a pitch of the refractive members is in a range from about 10 μ

m to about 100 μ

m.

24. The backlight assembly of claim 20, wherein the height of each of the refractive members is larger than a thickness of the polarization extraction layer.

25. The backlight assembly of claim 20, wherein the light source and the plurality of the refractive members are disposed to extend in the same direction.

26. The backlight assembly of claim 15, wherein the polarization transformation layer has a plurality of refractive indexes varying according to direction.

27. The backlight assembly of claim 26, wherein a difference between first and second refractive indexes among the refractive indexes is in a range from about 0.01 to 0.50 bout.

28. The backlight assembly of claim 26, wherein the first refractive index is in a range from about 1.0 to about 2.0.

29. The backlight assembly of claim 26, wherein the second refractive index is in a range from about 1.0 to about 2.5.

30. The backlight assembly of claim 29, wherein the polarization extraction layer includes a plurality of liquid crystal polymers.

31. The backlight assembly of claim 29, wherein the polarization transformation layer passes only an S polarization component.

32. The backlight assembly of claim 29, further comprising a protective layer on the polarization extraction layer to protect the polarization extraction layer.

33. The backlight assembly of claim 29, wherein a plurality of prisms are disposed on a surface opposite to the surface of the light guiding plate body.

34. The backlight assembly of claim 15, wherein the light source is a lamp.

35. The backlight assembly of claim 15, wherein the light source is a linear light source including light emitting diodes.

36. A display device comprising:

a panel unit for displaying an image;

a light source for supplying light to the panel unit; and

a light guiding plate for guiding light emitted from the light source,

wherein the light guiding plate comprises;

a light guiding plate body;

a polarization transformation layer on a surface of the light guiding plate body to transform a polarization component of light emitted through the light guiding plate; and

a polarization extraction layer on the polarization transformation layer.

37. The display device of claim 36, wherein the polarization transformation layer transforms a P polarization component into a sum of P and S polarization components.

38. The display device of claim 36, wherein the polarization transformation layer allows the light to be subject to birefringence.

39. The display device of claim 36, wherein the polarization transformation layer is a retardation film.

40. The display device of claim 39, wherein the retardation film includes at least one resin selected from a group consisting of poly ethylene terephthalate PET and poly ethylene naphthalate PEN.

41. The display device of claim 36, wherein a plurality of refractive members are disposed on the surface of the light guiding plate body to be separated from each other and extend in a predetermined direction.

42. The display device of claim 41, wherein a height of each of the refractive members is in a range from about 5 μ

m to about 12 μ

m.

43. The display device of claim 41, wherein a vertex angle of each of the refractive members is in a range from about 30°

to about 70°

.

44. The display device of claim 41, wherein a pitch of the refractive members is in a range from about 10 μ

m to 100 μ

m.

45. The display device of claim 36, wherein the polarization transformation layer has a plurality of refractive indexes varying according to direction.

46. The display device of claim 36, wherein the polarization extraction layer includes a plurality of liquid crystal polymers.

47. The display device of claim 36, wherein the panel unit is a liquid crystal display panel.

48. The display device of claim 36, wherein the panel unit is disposed to directly face the light guiding plate.