| 摘要 |
PROBLEM TO BE SOLVED: To provide a light, small-sized, and wide-angle telecentric retrofocus lens of simple constitution which has small chromatic aberration of magnification generation and small distortion and performs high-definition image projection used for an enlargement projection device. SOLUTION: The retrofocus lens which has a plurality of lenses and comprises three lens groups across the widest lens gap and 2nd long lens gap has a 1st lens group with negative refracting power which is composed of only a negative lens and has at least one aspherical surface, a 2nd lens group with positive refracting power, and a 3rd lens group with positive refracting power which is composed of at least≤6 lenses in order from an enlargement side and satisfies a condition of f3/f12¾<0.4, where fi is the a focal length of an (i)th lens and f12 is the composite focal length of the 1st lens group and 2nd lens group. COPYRIGHT: (C)2006,JPO&NCIPI
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