| 摘要 |
PROBLEM TO BE SOLVED: To provide an imaging lens capable of maintaining optical performance and reducing size and weight. SOLUTION: The imaging lens is constituted by disposing: a first lens 2 which is a meniscus lens having positive power whose convex surface faces to an object side; a diaphragm 3; a second lens 4 which is a meniscus lens having positive power whose convex surface faces to an imaging surface side; and a third lens 5 which is a biconcave lens having negative power from the object side, wherein the following inequalities are satisfied; 1.3≥L/fl≥1, 0.8≥f<SB>1</SB>/fl≥0.6, 0.12≥f<SB>1</SB>/f<SB>2</SB>>0 and -0.1≥f<SB>1</SB>/f<SB>3</SB>≥-0.25 äprovided that L:entire length of the lens system (distance from the surface 2a of the object side of the first lens 2 to the imaging surface 7 (air conversion length)), fl: focal distance of the entire lens system, f<SB>1</SB>: focal distance of the first lens 2, f<SB>2</SB>: focal distance of the second lens 4, and f<SB>3</SB>: focal distance of the third lens 5}. COPYRIGHT: (C)2007,JPO&INPIT |
