| 摘要 |
PROBLEM TO BE SOLVED: To provide an image reading lens and an image reading optical system in which various aberrations are satisfactorily corrected and, in particular, a color aberration and magnification color aberration on an axis are satisfactorily corrected at the same time, and to provide an image reader capable of satisfactorily reading an image by using the image reading lens and the image reading optical system. SOLUTION: In relation to an aperture diaphragm St, a first lens group GR1, second lens group GR2, and third lens group GR3 are disposed on the object side, and a fourth lens group GR4, fifth lens group GR5, and sixth lens group GR 6 are disposed on the image side. In each lens group, at least all positive lenses satisfy the conditional formula (1):νd>60.0. At least two positive lenses in the first or third lens group GR1 or GR3 and at least two positive lenses in the fourth or sixth lens roup GR4 or GR6 satisfy conditional formula (2):Δθ<SB>g, d</SB>>0.015, whereinνd represents Abbe's number relative to line d andΔθ<SB>g, d</SB>represents abnormal dispersibility. COPYRIGHT: (C)2008,JPO&INPIT
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