Title:
【発明の名称】拡大投影レンズ
Document Type and Number:
Japanese Patent JP3037967
Kind Code:
B2
Abstract:
PURPOSE:To obtain the imaging performance which is high up to a periphery by constituting the above lens of 1st to 5th lens groups, constituting the 1st lens group of the combined lens of a negative lens and a positive lens and satisfying specific conditions. CONSTITUTION:This lens is constituted, successively from an object side, of the 1st lens group of menicus, the concave face of which is directed to the object side, the 2nd lens group of a biconvex lens, the 3rd lens group of a posi tive menicus lens, the convex face of which is directed to the object side, the 4th lens group of a biconvex lens, and the 5th lens group of a biconvex lens. The 1st lens group is constituted of the combined lens of the negative lens and the positive lens. Equations I to VIII are satisfied. In the equations I to VIII, ri: the radius of curvature of the i-th lens face successively from the object side, fi: the focal length of the i-th lens group, f: the focal length of the entire system, nu+: the Abbe number of the positive lens of the 1st lens group, nu-: the Abbe number of the negative lens of the 1st lens group, n+: the average value of the refractive index of all the positive lenses. The projection enlarging lens having the imaging performance good up to the periphery is obtd. in this way.
Inventors:
Tetsuya Abe
Yasunori Arai
Yasunori Arai
Application Number:
JP17105490A
Publication Date:
May 08, 2000
Filing Date:
June 28, 1990
Export Citation:
Assignee:
Asahi Optical Co., Ltd.
International Classes:
G02B9/60; G02B13/24; (IPC1-7): G02B13/24
Domestic Patent References:
| JP56123510A |
Attorney, Agent or Firm:
Hideyuki Kanai