Light guide, illuminating device having the light guide, and image reading device and information processing apparatus having the illuminating device

• US 20030076551A1
• Filed: 11/18/2002
• Published: 04/24/2003
• Est. Priority Date: 01/19/1993
• Status: Active Grant

• Current Assignee: Chugai Seiyaku Kabushiki Kaisha (Roche Holding AG)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Itabashi, Satoshi, Takeda, Shinichi, Kawai, Tatsundo, Hamamoto, Osamu, Iso, Toshimitsu
• Granted Patent: US 7,057,778 B2
• Time in Patent Office: Days
• US Class Current: 358/475
• CPC Class Codes: G02B 2006/0098 for scanning
• CPC Class Codes: G02B 6/0001 specially adapted for lighting devices or systems lighting or signalling on vehicles using light guides B60Q1/00; lighting devices for vehicle dashboards B60Q3/10; lighting devices for vehicle interior using light guides B60Q3/62; lighting devices mounted on the vehicle rear part using light guides F21S43/235; measuring arrangements having light conducting pointers G01D13/265; illumination of liquid crystal displays G02F1/1336; illuminated signs G09F13/00
• CPC Class Codes: G02B 6/0013 Means for improving the coupling-in of light from the light source into the light guide coupling light into light guides in general G02B6/42
• CPC Class Codes: G02B 6/0031 Reflecting element, sheet or layer
• 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: G02B 6/0043 provided on the surface of the light guide
• CPC Class Codes: G02B 6/0046 Tapered light guide, e.g. wedge-shaped light guide
• 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 6/10 of the optical waveguide type G02B6/02, G02B6/24 take precedence; devices or arrangements for the control of light by electric, magnetic, electro-magnetic or acoustic means G02F1/00; transferring the modulation of modulated light G02F2/00; optical logic elements G02F3/00; optical analogue/digital converters G02F7/00
• CPC Class Codes: G02B 6/42 Coupling light guides with opto-electronic elements
• CPC Class Codes: H04N 1/02815 Means for illuminating the original, not specific to a particular type of pick-up head
• CPC Class Codes: H04N 1/0282 Using a single or a few point light sources, e.g. a laser diode
• CPC Class Codes: H04N 1/02835 in combination with a light guide, e.g. optical fibre, glass plate light-guides per se G02B6/00
• CPC Class Codes: H04N 1/0284 in combination with a light integrating, concentrating or diffusing cavity
• CPC Class Codes: H04N 1/02885 Means for compensating spatially uneven illumination, e.g. an aperture arrangement
• CPC Class Codes: H04N 1/0289 Light diffusing elements, e.g. plates or filters optical diffusing elements per se G02B5/02
• CPC Class Codes: H04N 1/03 with photodetectors arranged in a substantially linear array
• CPC Class Codes: H04N 1/0313 Direct contact pick-up heads, i.e. heads having no array of elements to project the scanned image elements onto the photodectors
• CPC Class Codes: H04N 1/0316 : illuminating the scanned image elements through the plane of the photodetector, e.g. back-light illumination
• CPC Class Codes: H04N 1/0318 : Integral pick-up heads, i.e. self-contained heads whose basic elements are a light-source, a lens array and a photodetector array which are supported by a single-piece frame
• CPC Class Codes: H04N 2201/03112 : Light source
• CPC Class Codes: H04N 2201/03125 : Light guide upstream of the scanned picture elements
• CPC Class Codes: H04N 2201/03129 : Transparent cover or transparent document support mounted on the head
• CPC Class Codes: H04N 2201/03141 : Photodetector lens
• CPC Class Codes: H04N 2201/03145 : Photodetector

Abstract

There is disclosed an illumination device in which a light guide is adapted to emil the light from a face thereof and is provided with an area, on a face opposite to the light emitting face, for diffusing and/or reflecting the light introduced into the light guide from an end face thereof or is provided with uneven light emitting characteristics along the longitudinal direction of the light guide, and the center of the light source positioned at the end of the light guide is placed at a position aberrated from the normal line to said area, whereby attained are compactnces, a low cost, a low eleotric power consumption, a high efficiency of utilization of the light emitted by the light source, and excellent and uniform illumination characteristics. There are also disclosed an image reading device and an information processing apparatus, equipped with the above-mentioned illumination device.

Claims

1. A light guide provided, on an end portion thereof, with a light entrance face and, on a face along the longitudinal direction, different from said end portion, with a light exit face for emitting the introduced light, comprising an area provided along said longitudinal direction in a part of the side opposite to said light exit face and adapted to reflect and/or diffuse the light introduced into the light guide.

2. A light guide according to claim 1, wherein said area is formed on an end face of a protruding portion formed on a face of the side opposite to said light exit face.

3. A light guide according to claim 1, wherein the cross section parallel to said end portion of said light guide is substantially rectangular.

4. A light guide according to claim 1, wherein the cross section parallel to said end portion of said light guide is substantially trapezoidal.

5. A light guide according to claim 1, wherein the cross section parallel to said end portion of said light guide is substantially rectangular in said end portion and is substantially trapezoidal in a central portion.

6. A light guide according to claim 1, wherein said area is formed with light reflecting paint.

7. A light guide according to claim 1, wherein said area is composed of a coarse surface.

8. A light guide according to claim 1, wherein said area comprises sawtooth-shaped reflecting faces.

9. A light guide according to claim 1, comprising a light condensing part at the side of said light exit face.

10. An illumination device comprising a translucent member provided, on an end portion thereof, with a light entrance face and, on a face along the longitudinal direction, different from said end portion, with a light exit face for emitting the introduced light;

and a light source for emitting the light to be introduced from said light entrance face;

wherein said translucent member comprises an area provided along said longitudinal direction in a part of the side opposite to said light exit face and adapted to reflect and/or diffuse the light introduced in said translucent member, and the center of said light source is placed in a position aberrated from the direction of the normal line to said area.

11. An illumination device according to claim 10, wherein said area is formed on an end face of a protruding portion formed on a face of the side opposite to said light exit face.

12. An illumination device according to claim 10, wherein the cross section parallel to said end portion of said translucent member is substantially rectangular.

13. An illumination device according to claim 10, wherein the cross section parallel to said end portion of said translucent member is substantially trapezoidal.

14. An illumination device according to claim 10, wherein the cross section parallel to said end portion of said translucent member is substantially rectangular in said end portion and is substantially trapezoidal in a central portion.

15. An illumination device according to claim 10, wherein said area is formed with light reflecting paint.

16. An illumination device according to claim 10, wherein said area is composed of a coarse surface.

17. An illumination device according to claim 10, wherein said area comprises sawtooth-shaped reflecting faces.

18. An illumination device according to claim 10, comprising a light condensing part at the side of said light exit face.

19. An illumination device according to claim 10, wherein said light entrance end portion is provided with a protruding portion adapted to fit with the light source.

20. An illumination device according to claim 10, wherein said light source is composed of a light-emitting diode.

21. An illumination device according to claim 10, wherein said translucent member is provided with a mounting portion.

22. An illumination device according to claim 10, comprising a casing fitting at least with said translucent member.

23. An information processing apparatus provided with:

(a) a photoelectric converting device having a plurality of photoelectric converting elements positioned opposite to the image of an original sheet to be read;

(b) an illumination device for illuminating said original sheet;

(c) transport means for transporting said original sheet;

(d) an output unit for recording an image on a document by electrical signals, corresponding to the image information; and

(e) a controller for controlling said photoelectric converting device, said light source, said transport means and said output unit,

wherein, in said illumination means including a translucent member provided, on an end portion thereof, with a light entrance face and, on a face along the longitudinal direction, different from said end portion, with a light exit face for emitting the introduced light, and a light source for emitting the light to be introduced from said light entrance face, said translucent member comprises an area provided along said longitudinal direction in a part of the side opposite to said light exit face and adapted to reflect and/or diffuse the light introduced in said translucent member, and the center of said light source is placed in a position aberrated from the direction of the normal line to said area.

24. An information processing apparatus according to claim 23, wherein said area is formed on an end face of a protruding portion formed on a face of the side opposite to said light exit face.

25. An information processing apparatus according to claim 23, wherein the cross section parallel to said end portion of said translucent member is substantially rectangular.

26. An information processing apparatus according to claim 23, wherein the cross section parallel to said end portion of said translucent member is substantially trapezoidal.

27. An information processing apparatus according to claim 23, wherein the cross section parallel to said end portion of said translucent member is substantially rectangular in said end portion and is substantially trapezoidal in a central portion.

28. An information processing apparatus according to claim 23, wherein said area is formed with light reflecting paint.

29. An information processing apparatus according to claim 23, wherein said area is composed of a coarse surface.

30. An information processing apparatus according to claim 23, wherein said area comprises sawtooth-shaped reflecting faces.

31. An information processing apparatus according to claim 23, comprising a light condensing part at the side of said light exit face.

32. An information processing apparatus according to claim 23, wherein said light entrance end portion is provided with a protruding portion adapted to fit with the light source.

33. An information processing apparatus according to claim 23, wherein said light source is composed of a light-emitting diode.

34. An information processing apparatus according to claim 23, wherein said translucent member is provided with a mounting portion.

35. An information processing apparatus according to claim 23, wherein said illumination means comprises a casing fitting at least with said translucent member.

36. An information processing apparatus according to claim 23, wherein said output unit comprises at least either of an ink jet recording head or a thermal recording head.

37. An information processing apparatus according to claim 36, wherein said ink jet recording head includes an electrothermal converting member for generating thermal energy for forming a bubble for discharging ink from said ink jet recording head.

38. An information processing apparatus according to claim 36, further comprising recovery means for rectifying discharge failure of said ink jet recording head and/or cleaning means for cleaning said ink jet recording head.

39. An information processing apparatus according to claim 23, further comprising communication means controlled by said controller.

40. An information processing apparatus according to claim 38, wherein said recovery means includes capping means.

41. An information processing apparatus according to claim 40, wherein said capping means includes an ink absorbent member.

42. An information processing apparatus according to claim 38, wherein said cleaning means is composed of a cleaning blade.

43. An information processing apparatus according to claim 23, further comprising a heater for heating the discharged recording sheet.

44. An information processing apparatus according to claim 36, wherein said ink jet recording head is a full-line recording head.

45. An image reading device including a translucent member provided, on an end portion thereof, with a light entrance face and, on a face along the longitudinal direction, different from said end portion, with a light exit face for emitting the introduced light, a light source for emitting the light to be introduced from said light entrance face, and a photoelectric converting device for receiving the light emitted from said light exit face and reflected by an illuminated surface, wherein said translucent member comprises an area provided along said longitudinal direction in a part of the side opposite to said light exit face and adapted to reflect and/or diffuse the light introduced in said translucent member, and the center of said light source is placed in a position aberrated from the direction of the normal line to said area.

46. An image reading device according to claim 45, wherein said area is formed on an end face of a protruding portion formed on a face of the side opposite to said light exit face.

47. An image reading device according to claim 45, wherein the cross section parallel to said end portion of said translucent member is substantially rectangular.

48. An image reading device according to claim 45, wherein the cross section parallel to said end portion of said translucent member is substantially trapezoidal.

49. An image reading device according to claim 45, wherein the cross section parallel to said end portion of said translucent member is substantially rectangular in said end portion and is substantially trapezoidal in a central portion.

50. An image reading device according to claim 45, wherein said area is formed with light reflecting paint.

51. An image reading device according to claim 45, wherein said area is composed of a coarse surface.

52. An image reading device according to claim 45, wherein said area comprises sawtooth-shaped reflecting faces.

53. An image reading device according to claim 45, comprising a light condensing part at the side of said light exit face.

54. An image reading device according to claim 45, wherein said light entrance end portion is provided with a protruding portion adapted to fit with the light source.

55. An image reading device according to claim 45, wherein said light source is composed of a light-emitting diode.

56. An image reading device according to claim 45, wherein said translucent member is provided with a mounting portion.

57. An image reading device according to claim 45, wherein said illumination device comprises a casing fitting at least with said translucent member.

58. A light guide adapted for use in an illumination device and adapted to introduce the light from a light source into a face constituting a part of a translucent member and to emit the light from a lateral face of said translucent member, wherein said translucent member itself has uneven light emitting characteristics along the longitudinal direction thereof.

59. A light guide according to claim 58, wherein the cross section of said translucent member is so formed as to condense the light in the light emitting direction.

60. A light guide according to claim 58, comprising an attenuating film for reducing the amount of light, in the vicinity of the light entrance side of the first-mentioned face constituting a part of the translucent member.

61. A light guide according to claim 58, comprising a light shielding film for intercepting the light, in the vicinity of the light entrance side of the first-mentioned face constituting a part of the translucent member.

62. A light guide according to claim 58, wherein a face of said translucent member, opposite to the light emitting face thereof, is inclined in the longitudinal direction with respect to said light emitting face.

63. An illumination device provided with a light source on a face constituting a part of a translucent member and adapted to emit the light from a lateral face of said translucent member, wherein said translucent member itself has uneven light emitting characteristics along the longitudinal direction thereof.

64. An illumination device according to claim 63, wherein the cross section of said translucent member is so formed as to condense the light in the light emitting direction.

65. An illumination device according to claim 63, comprising an attenuating film for reducing the amount of light, in the vicinity of the light entrance side of the first-mentioned face constituting a part of the translucent member.

66. An illumination device according to claim 63, comprising a light shielding film for intercepting the light, in the vicinity of the light entrance side of the first-mentioned face constituting a part of the translucent member.

67. An illumination device according to claim 63, wherein a face of said translucent member, opposite to the light emitting face thereof, is inclined in the longitudinal direction with respect to said light emitting face.

68. An image reading device including an illumination device provided with a light source on a face constituting a part of a translucent member and adapted to emit the light from a lateral face of said translucent member, and a photoelectric converting device for receiving the light emitted from said illumination device and reflected by an illuminated surface, wherein said translucent member itself has uneven light emitting characteristics along the longitudinal direction thereof.

69. An image reading device according to claim 68, wherein the cross section of said translucent member is so formed as to condense the light in the light emitting direction.

70. An image reading device according to claim 68, comprising an attenuating film for reducing the amount of light, in the vicinity of the light entrance side of the first-mentioned face constituting a part of the translucent member.

71. An image reading device according to claim 68, comprising a light shielding film for intercepting the light, in the vicinity of the light entrance side of the first-mentioned face constituting a part of the translucent member.

72. An image reading device according to claim 68, wherein a face of said translucent member, opposite to the light emitting face thereof, is inclined in the longitudinal direction with respect to said light emitting face.

73. An information processing apparatus provided with:

(a) a photoelectric converting device having a plurality of photoelectric converting elements positioned opposite to the image of an original sheet to be read;

(b) an illumination device for illuminating said original sheet, provided with a light source on a face constituting a part of a translucent member and adapted to emit the light from a lateral face of said translucent member;

(c) transport means for transporting said original sheet;

(d) an output unit for recording an image on a document by electrical signals, corresponding to the image information; and

(e) a controller for controlling said photoelectric converting device, said light source, said transport means and said output unit,

wherein said translucent member itself has uneven light emitting characteristics along the longitudinal direction thereof.

74. An information processing apparatus according to claim 73, wherein the cross section of said translucent member is so formed as to condense the light in the light emitting direction.

75. An information processing apparatus according to claim 73, comprising an attenuating film for reducing the amount of light, in the vicinity of the light entrance side of the first-mentioned face constituting a part of the translucent member.

76. An information processing apparatus according to claim 73, comprising a light shielding film for intercepting the light, in the vicinity of the light entrance side of the first-mentioned face constituting a part of the translucent member.

77. An information processing apparatus according to claim 73, wherein a face of said translucent member, opposite to the light emitting face thereof, is inclined in the longitudinal direction with respect to said light emitting face.

78. An information processing apparatus according to claim 73, wherein said light source is composed of a light-emitting diode.

79. An information processing apparatus according to claim 73, wherein said output unit is provided with at least either of an ink jet recording head and a thermal recording head.

80. An information processing apparatus according to claim 79, wherein said ink jet recording head includes an electrothermal converting member for generating thermal energy for forming a bubble for discharging ink from said ink jet recording head.

81. An information processing apparatus according to claim 79, further comprising recovery means for rectifying discharge failure of said ink jet recording head and/or cleaning means for cleaning said ink jet recording head.

82. An information processing apparatus according to claim 73, further comprising communication means controlled by said controller.

83. An information processing apparatus according to claim 81, wherein said recovery means includes capping means.

84. An information processing apparatus according to claim 83, wherein said capping means includes an ink absorbent member.

85. An information processing apparatus according to claim 81, wherein said cleaning means is composed of a cleaning blade.

86. An information processing apparatus according to claim 73, further comprising a heater for heating the discharged recording sheet.

87. An information processing apparatus according to claim 79, wherein said ink jet recording head is a full-line recording head.