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 |
代理机构 |
|
代理人 |
|
主权项 |
|
地址 |
|