Surface lighting device and a display having such a lighting device

• US 5,438,484 A
• Filed: 12/03/1992
• Issued: 08/01/1995
• Est. Priority Date: 12/06/1991
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Mori, Hideo, Yamamoto, Takashi, Takabayashi, Hiroshi, Kanda, Toshiyuki, Tajima, Hisao
• Primary Examiner(s): Dority, Carroll B.
• Application Number:
  US07/984,836
• Time in Patent Office: 971 Days
• Field of Search: 362/31, 362/26, 362/27, 248/316.7, 248/74.2, 385/15, 385/31, 385/95, 385/96, 385/98, 385/901
• US Class Current: 362/613
• CPC Class Codes: G02B 6/0026 Wavelength selective element, sheet or layer, e.g. filter or grating
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• CPC Class Codes: G02B 6/0051 Diffusing sheet or layer
• CPC Class Codes: G02B 6/0055 Reflecting element, sheet or layer
• CPC Class Codes: G02B 6/0061 to provide homogeneous light output intensity
• CPC Class Codes: G02B 6/0068 Arrangements of plural sources, e.g. multi-colour light sources
• CPC Class Codes: G02B 6/0071 with elongated shape, e.g. tube
• CPC Class Codes: G02B 6/009 of the light source in the package G02B6/0021 takes precedence
• CPC Class Codes: G09F 13/0409 Arrangements for homogeneous illumination of the display surface, e.g. using a layer having a non-uniform transparency arrangements of reflectors G09F13/14
• CPC Class Codes: G09F 13/0454 Slidable panels or parts
• CPC Class Codes: G09F 2013/1827 Prismatic window
• CPC Class Codes: G09F 2013/1831 using more than one light source
• CPC Class Codes: Y10S 385/901 Illuminating or display apparatus

Abstract

A surface lighting device receiving incident rays through two opposing faces of a light guide from light source to emit the incident rays from a face different from the two faces. The light guide is divided into plural divisions which are jointed together.

Claims

1. A lighting device with a light emitting flat surface, comprising:

a light guide having the emitting surface, and a pair of end surfaces crossing the light emitting surface; and

two light sources arranged correspondingly to the pair of end surfaces, wherein

said light guide comprises plural light transmitting members joined together, so that the junction surface therebetween crosses the light emitting surface.

2. A surface lighting device according to claim 1, wherein

said light sources are linear light sources.

3. A surface lighting device according to claim 1, wherein

said light sources are linear light sources and said light guide is divided at positions parallel to said linear light sources.

4. A lighting device according to claim 1, wherein said light guide is divided at positions having equal or substantially equal distances from said light sources.

5. A surface lighting device according to claim 1, wherein

the junction of said light guide is made by adhesives, setting, or welding.

6. A surface lighting device according to claim 5, wherein

said welding is a ultrasonic welding.

7. A surface lighting device according to claim 1, wherein

said light guide is divided in linear symmetry.

8. A surface lighting device according to claim 1, wherein

said light guide is divided at positions in the central or substantially central portion of said light guide and parallel or substantially parallel to said two opposing faces.

9. A surface lighting device according to claim 8, wherein

said light guide is further divided at positions having an equal distance or substantially equal distance from said positions where the light guide is divided.

10. A surface lighting device according to claim 1, wherein

said light guide is divided into at least three portions.

11. A surface lighting device according to claim 10, wherein

the junctions between surfaces of said light guide are inclined to the surface to which the rays of light from the light guide are irradiated.

12. A surface lighting device according to claim 11, wherein

the angles of said inclination are 245°

to 90°

to the face opposite to said surface to be irradiated.

13. A surface lighting device according to claim 4, wherein

the junctions between surfaces of said light guide are inclined to the face to emit the rays of light from the light guide.

14. A surface lighting device according to claim 13, wherein

the angles of said inclination are 245°

to 90°

to the face opposite to said face of emission.

15. A surface lighting device according to claim 1, wherein

the thicknesses of said light guide are different on said light source side and said positions for its division.

16. A surface lighting device according to claim 15, wherein

the thickness of said light guide is thicker on said light source side than the thickness of said position for its division.

17. A lighting device according to claim 1, wherein

said light guide is divided by diagonal lines.

18. A surface lighting device according to claim 1, wherein

said light guide is configured to be quadrangle for its light emission face.

19. A surface lighting device according to claim 18, wherein

light sources are arranged respectively for a set of opposing sides of said quadrangle.

20. A surface lighting device according to claim 1, wherein

said light guide is divided in point symmetry.

21. A surface lighting device according to claim 1, wherein

said light guide is made of glass or plastic material.

22. A surface lighting device according to claim 21, wherein

said plastic material is acrylic resin.

23. A surface lighting device according to claim 1, wherein

said device has a reflection board opposing to a surface opposite to said light emission face of said light guide.

24. A surface lighting device according to claim 1, wherein

said device has a diffusion board on said light emission face side of said light guide.

25. A surface lighting device according to claim 1, wherein

a diffusion reflection pattern is provided on the face side opposite to the light emission face side of said light guide.

26. A surface lighting device according to claim 25, wherein

said diffusion reflection pattern is arranged in such a manner that the arrangement density on said incident light side or in the position farther away from said position where the light guide is divided is higher than the arrangement density on the incident side of light from said light source or the position where said light guide is divided.

27. A surface lighting device according to claim 1, wherein

said light source is installed by clip shaped members having spring capability.

28. A surface lighting device according to claim 27, wherein

said clip shaped members are arranged on a reflection board which reflects rays of light from said light source.

29. A surface lighting device according to claim 28, wherein

said reflection board is further provided with leads for supplying power to said light source.

30. A surface lighting device according to claim 23, wherein

said reflection board and/or light guide is arranged to set the color of said reflection board and/or light guide against the standard color within a range of -2.0 to 0 at Δ

b value in CIE1976L*a*b* chromatic space.

31. A surface lighting device according to claim 19, wherein

of said light sources, the length of effective emission portions of the light sources is longer than the length of effective emission surface of the surface lighting device on the side where said light sources are arranged for those arranged on the two opposing side ends, and is shorter than the length of the effective emission surface of the surface lighting device on the side where said light sources are arranged for those arranged on the other two opposing side ends.

32. A surface lighting device according to claim 31, wherein

the configuration of said effective emission surface is rectangular and the lengths of effective emission portions of said light sources are equal.

33. Surface lighting means, comprising:

a light guide having a light emitting flat surface and a pair of end surfaces crossing the light emitting surface;

two light sources arranged correspondingly to the pair of end surfaces; and

a display having a display panel, said surface lighting means illuminating said display panel with rays of light emitted from said light emitting flat surface, and wherein

said light guide comprises plural light transmitting members joined together, so that the junction surface therebetween crosses the light emitting surface.

34. Surface lighting means and a display according to claim 33, wherein

said display panel is a liquid crystal display panel.

35. Surface lighting means and a display according to claim 33, wherein

said light sources are linear light sources.

36. Surface lighting means and a display according to claim 33, wherein

said light sources are linear light sources, and said light guide is divided at positions parallel to said linear light sources.

37. Surface lighting means and a display according to claim 33, wherein

said light guide is divided at positions having equal or substantially equal distances from said light sources.

38. Surface lighting means and a display according to claim 33, wherein the plural divisions are joined by adhesives, setting, or welding.

39. Surface lighting means and a display according to claim 38, wherein

said welding is a ultrasonic welding.

40. Surface lighting means and a display according to claim 33, wherein

said light guide is divided in linear symmetry.

41. Surface lighting means and a display according to claim 33, wherein

said light guide is divided at positions in the central or substantially central portion of said light source and parallel or substantially parallel to said two opposing faces.

42. Surface lighting means and a display according to claim 41, wherein

said light guide is further divided at positions having an equal distance or substantially equal distance from said positions where the light guide is divided.

43. Surface lighting means and a display according to claim 33, wherein

said light guide is divided into at least three portions,

44. Surface lighting means and a display according to claim 43 wherein

the junctions between surfaces of said light guide are inclined to the surface to which the rays of light from the light guide are irradiated,

45. Surface lighting means and a display according to claim 44, wherein

the angles of said inclination are 245°

to 90°

to the face opposite to said surface to be irradiated.

46. Surface lighting means and a display according to claim 37, wherein

the junctions between surfaces of said light guide are inclined to the faces to emit the rays of light from the light guide.

47. Surface lighting means and a display according to claim 46, wherein

the angles of said inclination are 245°

to 90°

to the face opposite to said face of emission.

48. Surface lighting means and a display according to claim 33, wherein

the thicknesses of said light guide are different on said light source side and said position for its division.

49. Surface lighting means and a display according to claim 48, wherein

the thickness of said light guide is thicker on said light source side than the thickness of said position for its division.

50. Surface lighting means and a display according to claim 33, wherein

said light guide is divided by diagonal lines.

51. Surface lighting means and a display according to claim 33, wherein

said light guide is configured to be quadrangle for its light emission face.

52. Surface lighting means and a display according to claim 51, wherein

light sources are arranged respectively for a set of opposing sides of said quadrangle.

53. Surface lighting means and a display according to claim 33, wherein

said light guide is divided in point symmetry.

54. Surface lighting means and a display according to claim 33, wherein

said light guide is made of glass or plastic material.

55. Surface lighting means and a display according to claim 54, wherein

said plastic material is acrylic resin.

56. Surface lighting means and a display according to claim 33, wherein

said means has a reflection board opposing to a surface opposite to said light emission face of said light guide.

57. Surface lighting means and a display according to claim 33, wherein

said means has a diffusion board on said light emission face side of said light guide.

58. Surface lighting means and a display according to claim 33, wherein

a diffusion reflection pattern is provided on the face side opposite to the light emission face side of said light guide.

59. Surface lighting means and a display according to claim 58, wherein

said diffusion reflection pattern is arranged in such a manner that the arrangement density on said incident light side or in the position farther away from said position where the light guide is divided is higher than the arrangement density on the incident side of light from said light source or the positions where said light guide is divided.

60. Surface lighting means and a display according to claim 33, wherein

said light sources are installed by clip shaped members having spring capability.

61. Surface lighting means and a display according to claim 60, wherein

said clip shaped members are arranged on a reflection board which reflects rays of light from said light source.

62. Surface lighting means and a display according to claim 61, wherein

said reflection board is further provided with leads for supplying power to said light source.

63. Surface lighting means and a display according to claim 56, wherein

said reflection board and/or light guide is arranged to set the color of said reflection board and/or light guide against the standard color within a range of -2.0 to 0 at Δ

b* value in CIE1976L*a*b* chromatic space.

64. Surface lighting means and a display according to claim 52, wherein

of said light sources, the length of effective emission portions of the light sources is longer than the length of effective emission surface of the surface lighting device on the side where said light sources are arranged for those arranged on the two opposing side ends, and is shorter than the length of the effective emission surface of the surface lighting device on the side where said light sources are arranged for those arranged on the other two opposing said ends.

65. Surface lighting means and a display according to claim 64, wherein

the configuration of said effective emission surface is rectangular and the lengths of effective emission portions of said light sources are equal.

66. Surface lighting means and a display according to claim 33, wherein

said display panel is the surface for the contents to be displayed.

67. A light guide for guiding a light introduced therein, comprising:

a light emitting flat surface and a pair of end surfaces crossing the light emitting surface, wherein

the light guide comprises plural light transmitting members joined together, so that the junction surface therebetween crosses the light emitting surface.

68. A light guide according to claim 67, wherein

the light guide is divided along the surface parallel to the light incident surface.

69. A light guide according to claim 67, wherein

the light guide is divided at a position equally distant from the incident surface.

70. A light guide according to claim 67, wherein

the sections of the light guide are joined together by means of adhesive, assembling or welding.

71. A light guide according to claim 70, wherein

the welding is ultrasonic welding.

72. A light guide according to claim 67, wherein

the light guide is divided linear-symmetrically.

73. A light guide according to claim 67, wherein

the light guide is further divided at a position equally distant from the former dividing position.

74. A light guide according to claim 67, wherein

the light guide is divided into three sections.

75. A light guide according to claim 74, wherein

one of the sections is inclined with regard to the light incident surface.

76. A light guide according to claim 75, wherein

the inclination angle is 45-90 degrees.

77. A light guide according to claim 67, wherein

a surface opposite to the light emission surface is inclined.

78. A light guide according to claim 67, wherein

a thickness of the light guide at the light incident surface is different from that at the dividing position.

79. A light guide according to claim 78, wherein

the thickness of the light guide at the light incident surface is greater.

80. A light guide according to claim 67, wherein

the plural light transmitting members are joined diagonally.

81. A light guide according to claim 67, wherein

four light transmitting members are formed.

82. A light guide according to claim 81, wherein

the four light transmitting members correspond to four sides of a quadrilateral.

83. A light guide according to claim 81, wherein

the light guide is made of a plastic or glass material.

84. A light guide according to claim 67, wherein

the light guide is provided with a diffusion plate at a side of light emission surface.

85. A light guide according to claim 67, wherein

the light guide is provided with a diffusion reflection pattern at a side opposite to the light emission surface.

86. A light guide according to claim 85, wherein

the diffusion reflection pattern arrangement density in the vicinity of the light emitting flat surface is smaller than that at a position distant from the light incident surface.