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

• US 7,847,880 B2
• Filed: 06/14/2006
• Issued: 12/07/2010
• 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
• Primary Examiner(s): Nguyen; Hoan C
• Application Number:
  US11/453,223
• Publication Number:
  US 20060279672A1
• Time in Patent Office: 1,637 Days
• Field of Search: 349/9, 349/61, 349/62, 349/63, 349/65, 349/67, 362615-620, 345/84, 345/87
• US Class Current: 349/61
• 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 which directly inputs a light emitted from a light source;

a plurality of refractive members are disposed on a surface of the light guiding plate body, and extend in a predetermined direction normal to the surface of the light guiding plate body;

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

a polarization extraction layer on the polarization transformation layer,

wherein refractive members are made of the same material as the light guiding plate body and the light guiding plate body, the polarization transformation layer, and the polarization extraction layer are made of different materials than each other.

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

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 thickness of each of the refractive members is in a range from about 5 μ

m to about 12 μ

m.

7. The light guiding plate of claim 1, wherein a vertex angle of each of the refractive members is in a range from about 30°

to about 70°

.

8. The light guiding plate of claim 1, wherein a pitch of each of the refractive members is in a range from about 10 μ

m to about 100 μ

m.

9. The light guiding plate of claim 1, wherein the height of each of the refractive members is larger than a thickness of the polarization extraction layer.

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

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

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

13. 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.

45. The light guiding plate of claim 1, wherein the plurality of refractive members are separated from each other.

14. A backlight assembly comprising:

a light source; and

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

wherein the light guiding plate comprises;

a light guiding plate body which directly inputs the light emitted from the light source;

a plurality of refractive members are disposed on a surface of the light guiding plate body, and extend in a predetermined direction normal to the surface of the light guiding plate body;

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

a polarization extraction layer on the polarization transformation layer,

wherein refractive members are made of the same material as the light guiding plate body and the light guiding plate body, the polarization transformation layer, and the polarization extraction layer are made of different materials than each other.

15. The backlight assembly of claim 14, wherein the polarization transformation layer transforms a portion of a P polarization component into a S polarization component.

16. The backlight assembly of claim 14, wherein the polarization transformation layer allows the light to be subject to birefringence.

17. The backlight assembly of claim 14, wherein the polarization transformation layer is a retardation film.

18. The backlight assembly of claim 17, wherein the retardation film includes at least one resin selected from a group consisting of poly ethylene terephthalate (PET) and poly ethylene naphthalate (PEN).

19. The backlight assembly of claim 14, wherein a thickness of each of the refractive members is in a range from about 5 μ

m to about 12 μ

m.

20. The backlight assembly of claim 14, wherein a vertex angle of each of the refractive members is in a range from about 30°

to about 70°

.

21. The backlight assembly of claim 14, wherein a pitch of the refractive members is in a range from about 10 μ

m to about 100 μ

m.

22. The backlight assembly of claim 14, wherein the height of each of the refractive members is larger than a thickness of the polarization extraction layer.

23. The backlight assembly of claim 14, wherein the light source and the plurality of the refractive members are disposed to extend in the same direction.

24. The backlight assembly of claim 14, wherein the polarization transformation layer has a plurality of refractive indexes varying according to direction.

25. The backlight assembly of claim 24, wherein a difference between first and second refractive indexes among the refractive indexes is in a range from about 0.01 to about 0.50.

26. The backlight assembly of claim 24, wherein the first refractive index is in a range from about 1.0 to about 2.0.

27. The backlight assembly of claim 24, wherein the second refractive index is in a range from about 1.0 to about 2.5.

28. The backlight assembly of claim 27, wherein the polarization extraction layer includes a plurality of liquid crystal polymers.

29. The backlight assembly of claim 27, wherein the polarization transformation layer passes only an S polarization component.

30. The backlight assembly of claim 27, further comprising a protective layer on the polarization extraction layer to protect the polarization extraction layer.

31. The backlight assembly of claim 14, wherein the light source is a lamp.

32. The backlight assembly of claim 14, wherein the light source is a linear light source including light emitting diodes.

46. The light guiding plate of claim 14, wherein the plurality of refractive members are separated from each other.

33. 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 a light emitted from the light source,

wherein the light guiding plate comprises;

a light guiding plate body which directly inputs the light emitted from the light source;

a plurality of refractive members are disposed on a surface of the light guiding plate body, and extend in a predetermined direction normal to the surface of the light guiding plate body;

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

a polarization extraction layer on the polarization transformation layer,

wherein refractive members are made of the same material as the light guiding plate body and the light guiding plate body, the polarization transformation layer, and the polarization extraction layer are made of different materials than each other.

34. The display device of claim 33, wherein the polarization transformation layer transforms a portion of a P polarization component into a S polarization component.

35. The display device of claim 33, wherein the polarization transformation layer allows the light to be subject to birefringence.

36. The display device of claim 33, wherein the polarization transformation layer is a retardation film.

37. The display device of claim 36, wherein the retardation film includes at least one resin selected from a group consisting of poly ethylene terephthalate PET and poly ethylene naphthalate PEN.

38. The display device of claim 33, wherein a thickness of each of the refractive members is in a range from about 5 μ

m to about 12 μ

m.

39. The display device of claim 33, wherein a vertex angle of each of the refractive members is in a range from about 30°

to about 70°

.

40. The display device of claim 33, wherein a pitch of the refractive members is in a range from about 10 μ

m to 100 μ

m.

41. The display device of claim 33, wherein the polarization transformation layer has a plurality of refractive indexes varying according to direction.

42. The display device of claim 33, wherein the polarization extraction layer includes a plurality of liquid crystal polymers.

43. The display device of claim 33, wherein the panel unit is a liquid crystal display panel.

44. The display device of claim 33, wherein the panel unit is disposed to directly face the light guiding plate.

47. The light guiding plate of claim 33, wherein the plurality of refractive members are separated from each other.