| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a bright both-side telecentric lens system. <P>SOLUTION: Both-side telecentric lens system 10 includes, in order from an enlargement side 11, a tele-type enlargement side lens group Gm comprising a positive first lens group G1 and a negative second lens group G2 and a reduction side lens group Gr comprising a positive third lens group G3, a diaphragm S and a positive fourth lens group G4. The lens L33 of the third lens group G3 facing the diaphragm S has a first facing surface concave with respect to the diaphragm S and the enlargement side lens of the fourth lens group G4 facing the diaphragm S has a second facing surface concave with respect to the diaphragm S. The effective aperture diameter Hf of the first facing surface, the air interval Df between the first facing surface and the diaphragm, the effective aperture diameter Hb of the second facing surface and the air interval Db between the second facing surface and the diaphragm satisfy the following conditions; (Hf/2)<Df<(3×Hf/2) and (Hb/2)<Db<(3×Hb/2). <P>COPYRIGHT: (C)2010,JPO&INPIT</p> |
