Image reading apparatus and illumination apparatus
AssigneeCanon Kabushiki Kaisha
InventorMasato Koshimizu
Life of this patent
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Abstract
An object of this invention is to read a high-quality image by detecting and correcting dirt, a scratch, or a watermark present on an original in an image reading apparatus for reading an original. To achieve this object, an original illumination unit in the image reading apparatus for reading an original includes a first light source for emitting light in at least the visible region, a second light source for emitting light in only the invisible region, and a light guide plate which has these light sources at an end face and distributes incident light from the end face to the entire flat surface.
Claims19
An image reading apparatus comprising:
- a first light source adapted to emit light of a visible region;
- a second light source adapted to emit light of an invisible region;
- a light guide plate which is parallel to an image plane to be read, and covers an image region to be read, and is configured to dispose said first and second light sources at an end face, wherein said light guide plate is adapted to guide incident light from said first and second light sources in a longitudinal direction along a surface of said light guide plate, and to uniformly emit the incident light from the surface which is perpendicular to an incident surface of light emitted from said first and second light source, and is larger than the incident surface, and covers the image region to be read;
- an image information reading unit adapted to read image information recorded on an original, on the basis of the light from said first light source that is guided by said light guide plate;
- a defect information reading unit adapted to read defect information present on an optical path extending from said light guide plate to image sensing unit, on the basis of the light from said second light source that is guided by said light guide plate;
- and
- a correction unit adapted to remove the defect information from the image information.
An image reading apparatus comprising:
- a first light source adapted to mainly emit light of a visible region;
- a second light source adapted to mainly emit light of an invisible region;
- a light guide plate which is parallel to an image plane to be read, and covers an image region to be read, and is adapted to guide light emitted by said first and second light sources in a longitudinal direction along a surface of said light guide plate and to illuminate overall image region of a transparent original by emitting the light from the surface which is perpendicular to an incident surface of light emitted from said first and second light source, and is larger than the incident surface, and covers the image region to be read;
- and
- a reading unit adapted to read transmitted light of the transparent original illuminated with light from said first or second light source that is guided by said light guide plate.
An illumination apparatus used in an image reading apparatus said illumination apparatus comprising:
- a first light source adapted to emit light of a visible region;
- a second light source adapted to emit light of an invisible region;
- and
- a light guide plate which is parallel to an image plane to be read, and covers an image region to be read, and is configured to dispose said first and second light sources at an end face, wherein said light guide plate is adapted to guide incident light from said first and second light sources in a longitudinal direction along a surface of said light guide plate, and to uniformly emit the incident light from the surface which is perpendicular to an incident surface on light emitted from said first and second light source, and is larger than the incident surface, and covers the image region to be read.
Dependencies are inferred from the claim text.