发明授权
- 专利标题: Wide angle copying lens system
- 专利标题(中): 广角复印镜头系统
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申请号: US839044申请日: 1986-03-12
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公开(公告)号: US4690518A公开(公告)日: 1987-09-01
- 发明人: Taira Kouchiwa , Kiichiro Nishina
- 申请人: Taira Kouchiwa , Kiichiro Nishina
- 申请人地址: JPX Tokyo
- 专利权人: Ricoh Company, Ltd.
- 当前专利权人: Ricoh Company, Ltd.
- 当前专利权人地址: JPX Tokyo
- 优先权: JPX60-50616 19850315
- 主分类号: G02B9/62
- IPC分类号: G02B9/62 ; G02B13/24
摘要:
This invention relates to a completely symmetrical wide angle copying lens system for a compact copying machine using a high output lamp. A topogon type wide angle lens system which is easy in correction of a radial curvature of field is basically used, and positive meniscus lenses having a small refracting power with a convex surface directed toward a diaphragm are symmetrically arranged with the diaphragm placed therebetween. A copying lens system is provided in which the tangential curvature of field and a deviation of the field cased by color are corrected by the construction as described above, the overall length of the lens system is shortened and even if a copying magnification is changed in the range of from .times.0.5 to .times.2.0, the performance is not deteriorated.