Display device, terminal device, light source device, and optical member

• US 20060238664A1
• Filed: 04/21/2006
• Published: 10/26/2006
• Est. Priority Date: 04/26/2005
• Status: Active Grant

• Current Assignee: NLT Technologies, Ltd.
• Original Assignee: NEC Corporation, NEC LCD Technologies Limited (NEC Corporation)
• Inventors: Uehara, Shin-ichi, Imai, Masao, Niioka, Shinya
• Granted Patent: US 8,339,538 B2
• Time in Patent Office: Days
• US Class Current: 349/1
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• CPC Class Codes: G02B 6/0036 2-D arrangement of prisms, protrusions, indentations or roughened surfaces
• 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: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133524 Light-guides, e.g. fibre-optic bundles, louvered or jalousie light-guides
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 2201/44 Arrangements combining different electro-active layers, e.g. electrochromic, liquid crystal or electroluminescent layers

Abstract

A display device comprising a light source and having an optical waveguide, a louver, an anisotropic scattering sheet, and a transmissive liquid crystal panel disposed along the path of light emitted from the light source. The light-restricting direction of the louver is tilted at an angle α from the Y-axis direction. The value of the angle α is set so that the arrangement direction of moiré created between the louver and the liquid crystal panel approaches the X-axis direction. A plurality of belt-shaped convex portions extending in the Y-axis direction are formed on the surface of the anisotropic scattering sheet, and are configured so that the scattering direction of the light has anisotropy. Specifically, scattering in the X-axis direction is increased, and scattering in the Y-axis direction is reduced. Moiré can thereby be reduced in a display device having increased directivity of the display.

Claims

1. A display device comprising:

a display panel in which a plurality of pixels are arranged in a matrix;

a light-direction restricting element which is interposed in the path of the light incident on the display panel or the light exiting from the display panel, and which is provided with a plurality of transparent areas and a plurality of light-absorbing areas arranged in alternating fashion in a first direction that differs from the arrangement direction of said pixels; and

anisotropic scattering unit for scattering incident light to a greater degree in the arrangement direction of moiré

created between said display panel and said light-direction restricting element than in said first direction.

2. The display device according to claim 1, wherein the direction of maximum scattering by said anisotropic scattering unit is one direction among the arrangement directions of said pixels.

3. The display device according to claim 1, wherein the direction of maximum scattering by said anisotropic scattering unit is the direction orthogonal to said first direction.

4. The display device according to claim 1, wherein said display panel, said light-direction restricting element, and said anisotropic scattering unit are arranged in sequence along said light path.

5. The display device according to claim 1, wherein said display panel, said anisotropic scattering unit, and said light-direction restricting element are arranged in sequence along said light path.

6. The display device according to claim 1, wherein said light-direction restricting element, said anisotropic scattering unit, and said display panel are arranged in sequence along said light path.

7. The display device according to claim 1, comprising a planar light source for emitting said light in a plane.

8. The display device according to claim 1, wherein said anisotropic scattering unit comprises a transparent substrate;

and a convex portion which extends in one direction and is formed on the surface of the transparent substrate.

9. The display device according to claim 8, wherein said anisotropic scattering unit is a one-dimensionally arranged prism sheet in which a plurality of prisms extending in one direction are arranged parallel to each other.

10. The display device according to claim 8, wherein said anisotropic scattering unit is a lenticular lens in which a plurality of cylindrical lenses extending in one direction are arranged parallel to each other.

11. The display device according to claim 1, wherein said anisotropic scattering unit comprises a transparent substrate;

and a concave portion which extends in one direction and is formed on the surface of the transparent substrate.

12. The display device according to claim 1, wherein said anisotropic scattering unit is a convex portion formed on the surface of said light-direction restricting element or the surface of said display panel.

13. The display device according to claim 12, wherein said anisotropic scattering unit is a one-dimensionally arranged prism structure in which a plurality of prisms extending in one direction are arranged parallel to each other.

14. The display device according to claim 12, wherein said anisotropic scattering unit is a lenticular lens structure in which a plurality of cylindrical lenses extending in one direction are arranged parallel to each other.

15. The display device according to claim 1, wherein said anisotropic scattering unit is a concave portion formed on the surface of said light-direction restricting element or the surface of said display panel.

16. The display device according to claim 1, wherein said anisotropic scattering unit is an anisotropic scattering adhesion layer for affixing said light-direction restricting element to said display panel.

17. The display device according to claim 1, wherein said anisotropic scattering unit is disposed inside said display panel.

18. The display device according to claim 17, wherein said display panel has an optical film, and said anisotropic scattering unit is an anisotropic scattering adhesion layer for fixing said optical film to the substrate of said display panel.

19. The display device according to claim 1, comprising a transparent/scattering state switching element which is capable of switching between a state for transmitting incident light and a state for scattering the light, and which is interposed in the path of the light that is incident on said display panel.

20. The display device according to claim 19, wherein said anisotropic scattering unit is an anisotropic scattering adhesion layer for affixing said transparent/scattering state switching element to said light-direction restricting element.

21. The display device according to claim 1, wherein said display panel is a liquid crystal panel.

22. The display device according to claim 21, wherein said liquid crystal display panel is a liquid crystal display panel that operates on a lateral field principle, a multi-domain vertical alignment principle, or a film-compensated TN principle.

26. A terminal device comprising the display device according to claim 1.

27. The terminal device according to claim 26, wherein the direction of maximum scattering of light by said anisotropic scattering unit is the direction perpendicular to the screen of said terminal device.

30. The terminal device according to claim 26, comprising a mobile telephone, a personal information terminal, a gaming device, a digital camera, a video camera, a video player, a notebook-type personal computer, a cash dispenser, or a vending machine.

23. A display device comprising:

a light-direction restricting element provided with a plurality of transparent areas and a plurality of light-absorbing areas arranged in alternating fashion in a first direction;

a transparent/scattering state switching element capable of switching between a state for transmitting the light incident from the light-direction restricting element and a state for scattering the light; and

a display panel which displays an image by transmitting the light incident from said transparent/scattering state switching element, and in which a plurality of pixels are arranged in a matrix in a direction that differs from said first direction;

wherein

said transparent/scattering state switching element scatters incident light to a greater degree in the arrangement direction of moiré

created between said display panel and said light-direction restricting element than in said first direction when in said light-transmitting state.

24. The display device according to claim 23, wherein said display panel is a liquid crystal panel.

25. The display device according to claim 24, wherein said liquid crystal display panel is a liquid crystal display panel that operates on a lateral field principle, a multi-domain vertical alignment principle, or a film-compensated TN principle.

28. A terminal device comprising the display device according to claim 23.

29. The terminal device according to claim 28, wherein the direction of maximum scattering of light by said transparent/scattering state switching element is the direction perpendicular to the screen of said terminal device when said transparent/scattering state switching element is in said light-transmitting state.

31. The terminal device according to claim 28, comprising a mobile telephone, a personal information terminal, a gaming device, a digital camera, a video camera, a video player, a notebook-type personal computer, a cash dispenser, or a vending machine.

32. A light source device comprising:

a planar light source for emitting light in a plane;

a light-direction restricting element which is interposed in the path of said light and which is provided with a plurality of transparent areas and a plurality of light-absorbing areas arranged in alternating fashion in a first direction; and

anisotropic scattering unit for scattering incident light to a greater degree in a direction other than said first direction.

33. The light source device according to claim 32, wherein the light-emitting surface of said planar light source has a rectangular shape, and the direction of maximum scattering by said anisotropic scattering unit is parallel to the extension direction of an arbitrary side of said rectangle.

34. The light source device according to claim 32, wherein the direction of maximum scattering by said anisotropic scattering unit is the direction orthogonal to said first direction.

35. The light source device according to claim 32, wherein said planar light source, said light-direction restricting element, and said anisotropic scattering unit are arranged in sequence.

36. The light source device according to claim 32, wherein said anisotropic scattering unit comprises a transparent substrate;

and a convex portion which extends in one direction and is formed on the surface of the transparent substrate.

37. The light source device according to claim 36, wherein said anisotropic scattering unit is a one-dimensionally arranged prism sheet in which a plurality of prisms extending in one direction are arranged parallel to each other.

38. The light source device according to claim 36, wherein said anisotropic scattering unit is a lenticular lens in which a plurality of cylindrical lenses extending in one direction are arranged parallel to each other.

39. The light source device according to claim 32, wherein said anisotropic scattering unit comprises a transparent substrate;

and a concave portion which extends in one direction and is formed on the surface of the transparent substrate.

40. The light source device according to claim 32, wherein said anisotropic scattering unit is a convex portion formed on the surface of said light-direction restricting element.

41. The light source device according to claim 40, wherein said anisotropic scattering unit is a one-dimensionally arranged prism structure in which a plurality of prisms extending in one direction are arranged parallel to each other.

42. The light source device according to claim 40, wherein said anisotropic scattering unit is a lenticular lens structure in which a plurality of cylindrical lenses extending in one direction are arranged parallel to each other.

43. The light source device according to claim 32, wherein said anisotropic scattering unit is a concave portion formed on the surface of said light-direction restricting element.

44. The light source device according to claim 32, comprising a transparent/scattering state switching element which is capable of switching between a state for transmitting incident light and a state for scattering the light, and which interposed in the path of the light emitted by said planar light source.

45. The light source device according to claim 44, wherein said anisotropic scattering unit is an anisotropic scattering adhesion layer for affixing said transparent/scattering state switching element to said light-direction restricting element.

46. A light source device comprising:

a planar light source of emitting light in a plane;

a light-direction restricting element which is interposed in the path of said light and which is provided with a plurality of transparent areas and a plurality of light-absorbing areas arranged in alternating fashion in a first direction; and

a transparent/scattering state switching element capable of switching between a state for transmitting the light incident from the light-direction restricting element and a state for scattering the light;

wherein

said transparent/scattering state switching element scatters incident light to a greater degree in a direction other than said first direction when in said light-transmitting state.

47. An optical member comprising:

a light-direction restricting element provided with a plurality of transparent areas and a plurality of light-absorbing areas arranged in alternating fashion in a first direction; and

anisotropic scattering unit which scatters incident light to a greater degree in a direction other than said first direction and which is integrally formed in the surface of the light-direction restricting element.

48. The optical member according to claim 47, wherein the external shape of said light-direction restricting element is rectangular, and the direction of maximum scattering by said anisotropic scattering unit is parallel to the extension direction of an arbitrary side of said rectangle.

49. The optical member according to claim 47, wherein the direction of maximum scattering by said anisotropic scattering unit is the direction orthogonal to said first direction.

50. The optical member according to claim 47, wherein said anisotropic scattering unit is a convex portion formed on the surface of said light-direction restricting element.

51. The optical member according to claim 47, wherein said anisotropic scattering unit is a concave portion formed on the surface of said light-direction restricting element.

52. The optical member according to claim 47, wherein said anisotropic scattering unit is a one-dimensionally arranged prism structure in which a plurality of prisms extending in one direction are arranged parallel to each other.

53. The optical member according to claim 47, wherein said anisotropic scattering unit is a lenticular lens structure in which a plurality of cylindrical lenses extending in one direction are arranged parallel to each other.

54. The optical member according to claim 47, wherein said anisotropic scattering unit is an anisotropic scattering adhesion layer.

55. The optical member according to claim 47, comprising a transparent/scattering state switching element capable of switching between a state for transmitting incident light and a state for scattering the light.

56. The optical member according to claim 55, wherein said anisotropic scattering unit is an anisotropic scattering adhesion layer, and said light-direction restricting element and said transparent/scattering state switching element are affixed to each other by the anisotropic scattering adhesion layer.

57. An optical member comprising a light-direction restricting element which is provided with a plurality of transparent areas and a plurality of light-absorbing areas arranged in alternating fashion in a first direction, and which scatters incident light to a greater degree in a direction other than said first direction when in said light-transmitting state.