发明授权
US4690518A Wide angle copying lens system 失效
广角复印镜头系统

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 .times.0.5 to .times.2.0, the performance is not deteriorated.
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