| 摘要 |
A color image readout lens having four lens groups of positive, positive or negative, negative, and positive refractive power, respectively, in order from the object side. The first lens group is formed of a first lens element having a convex surface on the object side. The second lens group has a convex surface of the object side and is formed of a biconvex lens element that is cemented to a biconcave lens element. The third lens group is formed of a fourth lens element that is cemented to a fifth lens element, with the fifth lens element having positive refractive power and a convex surface on the image side. A fourth lens group is formed of a sixth lens element having a convex surface on the image side. Various conditions are satisfied in order to favorably correct the various aberrations.
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