| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical system and an image reader capable of optically correcting chromatic aberration of magnification due to manufacture variation (eccentricity) of lenses and characteristic variation in glass (variation in Abbe's number) by arranging a position adjusting means for adjusting the position of a diffractive optical element from outside an effective optical path, and also, capable of reducing color slippage, further, capable of accurate reading an image. SOLUTION: In the optical system provided with the lens and the diffractive optical element on one optical axis, the position adjusting means capable of adjusting the position of the diffractive optical element is arranged outside the effective optical path. COPYRIGHT: (C)2005,JPO&NCIPI
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