| 摘要 |
PROBLEM TO BE SOLVED: To provide an exposure optical system for an original reader by which the S/N of an output of an image pickup means can be enhanced by optimizing the illuminance distribution of an original face with a simple configuration without increasing the luminance of light sources and the number of installed light sources. SOLUTION: An optical path correction body 4 is placed on an upper face of an LED line light source 51 of a close contact type read unit 50. A glass made protection plate 5 is placed on the upper face of the optical path correction body 4. A diffraction grating is formed in the optical path correction body 4 by engraving grooves (grating grooves) 4A onto the surface of the transparent plate. When using LEDs for a light source, since a wavelength band is comparatively narrow, the optical path can be converted by utilizing diffraction. Thus, the optical path of the light emitted from the LED line light source 51 can be corrected through the optical path correction body 4. As a result, the original face can be exposed with the illuminance distribution suitable for reading.
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