| 摘要 |
PROBLEM TO BE SOLVED: To obtain an original reading lens which compensates axial chromatic aberration is extremely excellently, has high contrast while maintaining a sufficiently bright Fno and a high numerical aperture up to the periphery part of a view angle, realizes a high MTF to high spatial frequency and excellently reads an original including a color original, and to provide an original reader using the original reading lens. SOLUTION: This original reading lens has a 1st group L1 including a 1st lens being a meniscus whose convex surface faces to an original surface side and having positive refractive power, a 2nd group L2 including a doublet obtained by bonding a 2nd lens having positive refractive power and a 3rd lens having negative refractive power and having negative refractive power as a whole, a 3rd group L3 including a 4th lens being a meniscus whose convex surface faces to an image surface side and having negative refractive power, and a 4th group L4 including a 5th lens having positive refractive power in order from the original surface side, and satisfies one or more conditions out of respective conditional expression.
|
