| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact, low-cost reading lens which has telecentricity on an image side and properly corrects chromatic aberration on an axis in a wide range from the c-line to the g-line.SOLUTION: A reading lens 1 has four-group, six-lens constitution including, in order from an object side to an image side, a first lens group G1 composed of a first lens L1 of a positive meniscus lens arranged so that a convex surface thereof faces the object side, a second lens group G2 obtained by cementing a positive second lens L2 and a negative third lens L3 and having negative refractive power as a whole, a third lens group G3 obtained by cementing a negative fourth lens L4 and a positive fifth lens L5 and having negative refractive power as a whole, and a fourth lens group G4 composed of a positive sixth lens L6. The reading lens 1 includes an aperture diaphragm AD between the second lens group G2 and the third lens group G3 and arrangement is performed to be substantially telecentric on the image side. FG is a parallel plate. |
