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

• US 7,057,778 B2
• Filed: 11/18/2002
• Issued: 06/06/2006
• Est. Priority Date: 01/19/1993
• Status: Expired due to Fees

• 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
• Primary Examiner(s): Lee, Cheukfan
• Application Number:
  US10/295,925
• Publication Number:
  US 20030076551A1
• Time in Patent Office: 1,296 Days
• Field of Search: 358/484, 358/475, 358/509, 358/474, 358/483, 358/482, 358/487, 358/506, 358512-514, 358/497, 358/494, 358/496, 358/505, 250/216, 250/208.1, 250/227.11, 250/227.2, 250234-236, 382/313, 382/318, 382/319, 382/312, 362/26, 362/31, 362/551, 362/800, 399/211, 359/34, 359209-211
• US Class Current: 358/484
• 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 emit 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 compactness, a low cost, a low electric 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. An image reading apparatus comprising:

a line sensor which reads an image and outputs an image signal corresponding thereto;

a light source;

a light guide member which illuminates an original in a line shape along a first reading direction which corresponds to a longitudinal direction of said line sensor, wherein said light source is arranged on an end surface of said light guide member, in the longitudinal direction thereof, said light guide member has a light emitting surface for illuminating the original in the line shape in the first reading direction of said line sensor and a reflection portion which is arranged on a surface different from said light emitting surface and along the first reading direction across the length of said light guide member so as to diffuse and/or reflect the light from said light source along the first reading direction, and said light guide member is arranged relative to said light source so that a line normal to an elongated area of said light guide member and passing through a center of the width of said reflection portion at a portion thereof which is relatively close to said light source is offset from a line extending in the longitudinal direction of said light guide member and passing through the center of said light source, when viewed from said light source;

a drive unit which moves a relative position between the image illuminated along the first reading direction by said light guide member and said line sensor, in a second reading direction different from the first reading direction; and

a control circuit which controls said light source, said line sensor and said drive unit,

wherein said reflection portion is arranged across the length of said light guide member so that at least the portion of said reflection portion is arranged so as to be offset from a center of a cross-section of said light guide member.

2. An image reading apparatus according to claim 1, further comprising a processor which processes the image signal output from said line sensor, and a transfer unit which transfers the image signal to an external processing apparatus.

3. An image reading apparatus according to claim 1, wherein said image reading apparatus is a color image reading apparatus.

4. An image reading apparatus comprising:

a line sensor which reads an image and outputs an image signal corresponding thereto;

a light source;

a light guide member which illuminates an original in a line shape along a first reading direction which corresponds to a longitudinal direction of said line sensor, wherein said light source is arranged on an end surface of said light guide member, in the longitudinal direction thereof, said light guide member has a light emitting surface for illuminating the original in the line shape in the first reading direction of said line sensor and a reflection portion which is arranged on a surface different from said light emitting surface and along the first reading direction across the length of said light guide member so as to diffuse and/or reflect the light from said light source along the first reading direction, and said light guide member is arranged relative to said light source so that a line normal to an elongated area of said light guide member and passing through a center of the width of said reflection portion at a portion thereof which is relatively close to said light source is offset from a line extending in the longitudinal direction of said light guide member and passing through the center of said light source, when viewed from said light source;

a drive unit which moves a relative position between the image illuminated along the first reading direction by said light guide member and said line sensor, in a second reading direction different from the first reading direction; and

a control circuit which controls said light source, said line sensor and said drive unit,

wherein said light guide member has a plurality of faces arranged perpendicular to each other and an inclined face that is inclined relative to said plurality of faces.

5. An image reading apparatus comprising:

a line sensor which reads an image and outputs an image signal corresponding thereto;

a light source;

a light guide member which illuminates an original in a line shape along a first reading direction which corresponds to a longitudinal direction of said line sensor, wherein said light source is arranged on an end surface of said light guide member, in the longitudinal direction thereof, said light guide member has a light emitting surface for illuminating the original in the line shape in the first reading direction of said line sensor and a reflection portion which is arranged on a surface different from said light emitting surface and along the first reading direction across the length of said light guide member so as to diffuse and/or reflect the light from said light source along the first reading direction, and said light guide member is arranged relative to said light source so that a line normal to an elongated area of said light guide member and passing through a center of the width of said reflection portion at a portion thereof which is relatively close to said light source is offset from a line extending in the longitudinal direction of said light guide member and passing through the center of said light source, when viewed from said light source;

a drive unit which moves a relative position between the image illuminated along the first reading direction by said light guide member and said line sensor, in a second reading direction different from the first reading direction; and

a control circuit which controls said light source, said line sensor and said drive unit,

wherein said light guide member has a plurality of faces arranged parallel to each other and an inclined relative face that is inclined to said plurality of faces.

6. A light guide member of a reading apparatus, for illuminating an original in a line shape along a first reading direction corresponding to a longitudinal direction of a line sensor, comprising:

a light source arranged on an end surface which is in a direction corresponding to the first reading direction;

a light emitting surface which irradiates light guided from said light source through said light guide member along the first reading direction, diagonally onto the original so as to illuminate the original in the line shape along the first reading direction; and

a reflection portion arranged along the first reading direction across the length of said light guide member so as to diffuse and/or reflect the light from said light source along the first reading direction,

wherein said reflection portion is arranged relative to said light source so that a line normal to said reflection portion and passing through a center of the width of said reflection portion at a portion thereof which is relatively close to said light source is offset from a center of said light source when viewed from said light source, and said normal line is also offset from a center of a side including said reflection portion when viewed from said light source.

7. A light guide member according to claim 6, wherein said light guide member reads a color image.

8. A light guide member according to claim 6, wherein said light guide member has a plurality of faces arranged perpendicular to each other and an inclined face that is inclined relative to said plurality of faces.

9. A light guide member according to claim 6, wherein said light guide member has a plurality of faces arranged parallel to each other and an inclined face that is inclined relative to said plurality of faces.

10. A light guide member according to claim 6, wherein the emission direction of the light emitted from said light emitting surface is set so that the light emitted diagonally from said light emitting surface is reflected by the original and then is focused onto said line sensor through an optical system.

11. A light guide member according to claim 6, wherein said light guide member and said light source are integrated into one unit which is to be combined with said line sensor.

12. A light guide member according to claim 11, further comprising a moving unit which effects relative movement in a second reading direction different from the first reading direction between said line sensor and the original illuminated in the line shape by said light guide member along the first reading direction.