发明名称 Wide angle copying lens system
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 x0.5 to x2.0, the performance is not deteriorated.
申请公布号 US4690518(A) 申请公布日期 1987.09.01
申请号 US19860839044 申请日期 1986.03.12
申请人 RICOH COMPANY, LTD. 发明人 KOUCHIWA, TAIRA;NISHINA, KIICHIRO
分类号 G02B9/62;G02B13/24;(IPC1-7):G02B9/62 主分类号 G02B9/62
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