| 摘要 |
PROBLEM TO BE SOLVED: To provide a wide-angle monofocal lens having high performance, made compact, and realizing the simplification of constitution. SOLUTION: The wide-angle monofocal lens is equipped with a 1st lens G1 which is a meniscus turning its concave surface toward an object side and at least one surface of which is formed to be aspherical, a diaphragm St, a 2nd lens G2 at least one surface of which is formed to be aspherical, the object-side surface of which is formed to be concave, and which has positive power, a 3rd lens G3 which is formed to be biconvex and has positive power, and a 4th lens G4 at least one surface of which is formed to be aspherical, the object-side surface of which is formed to be concave and which has negative power in order from the object side, and satisfies following conditional expressions (1) and (2). (1): 5.0<¾f1/f¾ and (2): 3.0>f3/f provided that (f) means the focal distance of the whole, f1 means the focal distance of the 1st lens G1, and f3 means the focal distance of the 3rd lens G3. COPYRIGHT: (C)2004,JPO&NCIPI
|
