| 摘要 |
An image reading lens is provided and includes: in order from an object side of the image reading lens, a first lens of a negative lens having a meniscus shape directing a concave surface toward the object side thereof; a second lens having a biconvex shape; a stop; a third lens of a positive lens having a meniscus shape directing a convex surface toward an image side thereof; and a fourth lens of a negative lens having a meniscus shape directing a concave surface toward the object side thereof. The image reading lens satisfies the following conditional expressions: <?in-line-formulae description="In-line Formulae" end="lead"?>2.4<f3/f<3.5<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>0.007<D2/f<0.028<?in-line-formulae description="In-line Formulae" end="tail"?> where f represents a focal length of the image reading lens, f3 represent a focal length of the third lens, and D2 represents a spacing between an image-side surface of the first lens and an object-side surface of the second lens.
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