Diffusely reflective polarizing film, display apparatus having the same, and method of manufacturing the same

• US 20060077547A1
• Filed: 10/07/2005
• Published: 04/13/2006
• Est. Priority Date: 10/08/2004
• Status: Abandoned Application

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Jung, Jin-Mi, Park, Jong-Dae, Lee, Jeong-Hwan, Choi, Jin-Sung, Kim, Dong-Hoon, Park, Jheen-Hyeok
• Application Number:
  US11/245,112
• Publication Number:
  US 20060077547A1
• Time in Patent Office: Days
• US Class Current: 359/487
• CPC Class Codes: G02B 5/0242 by means of dispersed particles
• CPC Class Codes: G02B 5/0257 creating an anisotropic diffusion characteristic, i.e. distributing output differently in two perpendicular axes
• CPC Class Codes: G02B 5/0268 characterized by the fabrication or manufacturing method
• CPC Class Codes: G02B 5/0284 used in reflection
• CPC Class Codes: G02B 5/0294 adapted to provide an additional optical effect, e.g. anti-reflection or filter
• CPC Class Codes: G02B 5/3016 involving passive liquid crystal elements optical properties of liquid crystals G02F1/0063; polarising elements associated with active liquid crystal devices G02F1/133528
• CPC Class Codes: G02F 1/133543 Cholesteric polarisers

Abstract

A diffusing reflective polarizing film has a liquid crystal film and a diffusing layer. The liquid crystal film includes a cholesteric liquid crystal diffusely reflecting a first component of a light substantially in parallel with a twisted axis of the cholesteric liquid crystal and transmitting a second component of the light different from the first component. The diffusing layer is attached to the liquid crystal layer to diffuse light from the liquid crystal layer. Thus, the diffusely reflective polarizing film may improve brightness uniformity, thereby preventing a warping phenomenon of the diffusely reflective polarizing film.

Claims

1. A diffusely reflective polarizing film, comprising:

a liquid crystal film having a cholesteric liquid crystal to reflect a first component of an incident light and to transmit a second component of the incident light; and

a diffusing layer attached with the liquid crystal film,

wherein the first component is substantially parallel with a rotated axis of the cholesteric liquid crystal, and the second component is different than the first component.

2. The film of claim 1, wherein the diffusing layer comprises:

a first diffusing layer attached with a lower surface of the liquid crystal film and that diffuses a light supplied to the liquid crystal film; and

a second diffusing layer attached with an upper surface of the liquid crystal film and that diffuses the light supplied from the liquid crystal film.

3. The film of claim 1, wherein the diffusing layer comprises at least one resin selected from the group consisting of a polycarbonate-based resin, a polysulfone-based resin, a polymethylmethacrylate-based resin, a polystyrene-based resin, a polyvinylchloride-based resin, a polyvinylalcohol-based resin, and a polynorbornene-based resin.

4. The film of claim 1, wherein the diffusing layer further comprises a diffusing agent that diffusesa light supplied to the diffusing layer.

5. The film of claim 4, wherein the diffusing agent comprises a silicon diffusing agent, a magnesium diffusing agent, or a calcium carbonate diffusing agent.

6. The film of claim 1, wherein the diffusing layer further comprises a cationic surfactant that insulates the liquid crystal film from static electricity.

7. The film of claim 1, further comprising an adhesive including an ultraviolet-curable material that attaches the diffusing layer with the liquid crystal film.

8. The film of claim 7, wherein the adhesive comprises a photopolymerizeable initiator and a photopolymerizeable monomer, or a photopolymerizeable oligomer,

wherein the photopolymerizeable initiator comprises at least one initiator selected from the group consisting of an acetophenone-based initiator, a benzophenone-based initiator, and a thioxanthone-based initiator,

wherein the photopolymerizeable monomer comprises at least one monomer selected from the group consisting of an acrylate-based monomer, an epoxy acrylate-based monomer, a polyester acrylate-based monomer, and an urethane acrylate-based monomer, and

wherein the photopolymerizeable oligomer comprises at least one oligomer selected from the group consisting of an acrylate-based oligomer, an epoxy acrylate-based oligomer, a polyester acrylate-based oligomer, and an urethane acrylate-based oligomer.

9. The film of claim 1, wherein the liquid crystal film comprises:

a base layer;

a liquid crystal layer provided on the base layer and having the cholesteric liquid crystal to circularly polarize light supplied from the base layer; and

a retardation layer to linearly polarize the circularly polarized light from the liquid crystal layer.

10. The film of claim 9, wherein the liquid crystal layer comprises:

a first liquid crystal layer to circularly polarize a light having a red wavelength range;

a second liquid crystal layer to circularly polarize a light having a green wavelength range; and

a third liquid crystal layer to circularly polarize a light having a blue wavelength range.

11. The film of claim 10, wherein the first liquid crystal layer, the second liquid crystal layer and the third liquid crystal layer are stacked on the base layer.

12. The film of claim 11, wherein the liquid crystal film further comprises:

a first adhesive attaching the first liquid crystal layer with the base layer;

a second adhesive attaching the second liquid crystal layer with the first liquid crystal layer; and

a third adhesive attaching the third liquid crystal layer with the second liquid crystal layer.

13. The film of claim 10, wherein the first liquid crystal layer comprises the cholesteric liquid crystal and a vertical alignment liquid crystal that are mixed at a ratio of approximately 8:

2, respectively.

14. The film of claim 10, wherein the second liquid crystal layer comprises the cholesteric liquid crystal and a vertical alignment liquid crystal that are mixed at a ratio of approximately 7:

3, respectively.

15. The film of claim 10, wherein the third liquid crystal layer comprises the cholesteric liquid crystal and a vertical alignment liquid crystal that are mixed at a ratio of approximately 6:

4, respectively.

16. The film of claim 9, wherein the base layer comprises a polyethyleneterephthalate-based resin.

17. The film of claim 9, wherein the retardation layer comprises a λ

/4 retardation layer, and a z-axis refractive index of the retardation layer is larger than a refractive index of the retardation layer with respect to an x-y plane of the retardation layer.

18. The film of claim 17, wherein the retardation layer has a phase delay of about 110 nm to about 125 nm.

19. The film of claim 1, wherein the diffusing layer is attached with a lower surface of the liquid crystal film to diffuse a light supplied to the liquid crystal film.

20. The film of claim 1, wherein the diffusing layer is attached with an upper surface of the liquid crystal film to diffuse a light supplied from the liquid crystal film.

21. A diffusely reflective polarizing film, comprising:

a base film; and

a plurality of polarizing particles comprising a copolymer,

wherein the base film comprises the polarizing particles to transmit a first component of a light supplied to the base film and to diffusely reflect a second component of the light.

22. The film of claim 21, wherein the polarizing particles comprise a polyethyleneterephthalate copolymer.

23. The film of claim 22, wherein the polarizing particles comprises a following bisphenol-based compound of formula

24. The film of claim 22, wherein the polarizing particles comprise a copolymer having a polymerization of a bisphenol-based monomer, an ethylene glycol-based monomer, and a carboxylic acid-based monomer.

25. The film of claim 21, wherein a weight percent of the polarizing particles is of about 0.01% to about 40%.

26. The film of claim 25, wherein the weight percent is of about 1% to about 30%.

27. The film of claim 21, wherein the polarizing particles are expanded such that a first axis direction of the polarizing particles is substantially perpendicular to a second axis direction of the polarizing particles, and

wherein an expansion ratio of the first axis direction with respect to the second axis direction is of about one to about ten times.

28. The film of claim 27, wherein the expansion ratio is of about two to about seven times.

29. The film of claim 21, wherein the polarizing particles have a specific gravity of about 1.22 g/cm.

30. The film of claim 21, wherein the polarizing particles have a refractive index of about 1.607.

31. The film of claim 21, wherein a thermal deflection temperature of the polarizing particles is about 105°

C.

32. The film of claim 21, wherein the base film comprises at least one resin selected from the group consisting of a polyethylenenaphthalate-based resin, a polycarbonate-based resin, a polysulfone-based resin, a polymethylmethacrylate-based resin, a polyvinylchloride-based resin, a polyvinylalcohol-based resin, and a polynorbornene-based resin.

33. The film of claim 21, further comprising a diffusing layer provided on a lower surface or an upper surface of the base film.

34. The film of claim 33, wherein the diffusing layer comprises at least one resin selected from the group consisting of a polycarbonate-based resin, a polyethyleneterephthalate-based resin, a polyimide-based resin, a polysulfone-based resin, a polymethylmethacrylate-based resin, a polystyrene-based resin, a polyvinylchloride-based resin, a polyvinylalcohol-based resin, and a polynorbornene-based resin.

35. A diffusely reflective polarizing film, comprising:

a base film;

a plurality of organic particles provided in the base film to transmit a first component of a light supplied to the base film and diffusely reflect a second component of the light; and

a diffusing layer attached with the base film.

36. The film of claim 35, wherein the diffusing layer comprises:

a first diffusing layer attached with a lower surface of the base film to diffuse the light supplied to the base film; and

a second diffusing layer attached with an upper surface of base film to diffuse a light supplied from the base film.

37. The film of claim 35, wherein the diffusing layer comprises at least one resin selected from the group consisting of a polycarbonate-based resin, a polyethyleneterephthalate-based resin, a polyimide-based resin, a polysulfone-based resin, a polymethylmethacrylate-based resin, a polystyrene-based resin, a polyvinylchloride-based resin, a polyvinylalcohol-based resin, and a polynorbornene-based resin.

38. The film of claim 37, wherein the diffusing layer further comprises a diffusing agent to diffuse a light supplied to the diffusing layer.

39. The film of claim 38, wherein the diffusing agent comprises a silicon diffusing agent, a magnesium diffusing agent, or a calcium carbonate diffusing agent.

40. The film of claim 35, wherein the diffusing layer further comprises a cationic surfactant to that insulates the liquid crystal layer from static electricity.

41. The film of claim 35, further comprising an adhesive comprising an ultraviolet-curable material to attach the diffusing layer with the base film.

42. The film of claim 41, wherein the adhesive comprises a photopolymerizeable initiator and a photopolymerizeable monomer, or a photopolymerizeable oligomer,

wherein the photopolymerizeable initiator comprises at least one initiator selected from the group consisting of an acetophenone-based initiator, a benzophenone-based initiator, and a thioxanthone-based initiator,

wherein the photopolymerizeable monomer comprises at least one monomer selected from the group consisting of an acrylate-based monomer, an epoxy acrylate-based monomer, a polyester acrylate-based monomer, and an urethane acrylate-based monomer, and

wherein the photopolymerizeable oligomer comprises at least one oligomer selected from the group consisting of an acrylate-based oligomer, an epoxy acrylate-based oligomer, a polyester acrylate-based oligomer, and an urethane acrylate-based oligomer.

43. The film of claim 35, wherein the base film comprises at least one resin selected from the group consisting of a polyethylenenaphthalate-based resin, a polycarbonate-based resin, a polyimide-based resin, a polysulfone-based resin, a polymethylmethacrylate-based resin, a polyvinylchloride-based resin, a polyvinylalcohol-based resin, and a polynorbornene-based resin.

44. The film of claim 35, wherein the organic particles comprise a plurality core-shell particles.

45. The film of claim 35, wherein the organic particles comprise:

a core portion comprising a butadiene and a styrene cross-linked to the butadiene; and

a shell portion comprising a polymethylmethacrylate and substantially surrounding the core portion.

46. A display apparatus, comprising:

a backlight assembly generating a light;

a diffusely reflective polarizing film provided on the backlight assembly and comprising;

a liquid crystal film comprising a cholesteric liquid crystal to reflect a first component of the light that is substantially parallel with a rotated axis of the cholesteric liquid crystal and to transmit a second component of the light that is different from the first component; and

a diffusing layer attached with the liquid crystal film, and

a display panel provided on the diffusely reflective polarizing film and that displays an image using a light supplied from the diffusely reflective polarizing film.

47. A display apparatus, comprising:

a backlight assembly generating a light;

a diffusely reflective polarizing film provided on the backlight assembly and comprising;

a base film; and

a plurality of polarizing particles comprising a copolymer, and

a display panel provided on the diffusely reflective polarizing film and that displays an image using a light from the diffusely reflective polarizing film,

wherein the base film comprises the polarizing particles to transmit a first component of a light supplied to the base film and to diffusely reflect a second component of the light.

48. A display apparatus, comprising:

a backlight assembly generating a light;

a diffusely reflective polarizing film provided on the backlight assembly and comprising;

a base film;

a plurality of organic particles provided in the base film to transmit a first component of a light supplied to the base film and to diffusely reflect a second component of the light; and

a diffusing layer attached with the base film, and

a display panel provided on the diffusely reflective polarizing film and that displays an image using a light from the diffusely reflective polarizing film.

49. A method of manufacturing a diffusely reflective polarizing film, comprising:

forming a liquid crystal film having a cholesteric liquid crystal to reflect a first component of a light and to transmit a second component of the light, the first component is substantially parallel with a rotated axis of the cholesteric liquid crystal and the second component is different from the first component; and

attaching a diffusing layer with the liquid crystal film.

50. The method of claim 49, wherein forming the liquid crystal film comprises:

forming a liquid crystal layer comprising the cholesteric liquid crystal on a base layer to circularly polarize a light from the base layer;

curing the liquid crystal layer; and

forming a retardation layer on the liquid crystal layer to linearly polarize the circularly polarized light.

51. The method of claim 50, wherein forming the liquid crystal layer further comprises:

mixing the cholesteric liquid crystal with a vertical alignment liquid crystal; and

adding an ultraviolet initiator to the mixture.

52. The method of claim 51, wherein curing the liquid crystal layer comprises:

irradiating an ultraviolet light upon the liquid crystal layer.

53. The method of claim 49, wherein attaching the diffusing layer with the liquid crystal film comprises:

applying an ultraviolet adhesive on the liquid crystal film;

applying the diffusing layer on the ultraviolet adhesive; and

curing the ultraviolet adhesive to attach the diffusing layer with the liquid crystal film.

54. A method of manufacturing a diffusely reflective polarizing film, comprising:

expanding a base film that comprises a plurality of organic particles comprising a core-shell-like structure; and

attaching a diffusing layer with the base film.

55. The method of claim 54, wherein attaching the diffusing layer with the base film comprises:

applying an ultraviolet adhesive on the base film;

applying the diffusing layer on the ultraviolet adhesive; and

curing the ultraviolet adhesive to attach the diffusing layer with the base film.