| 摘要 |
PROBLEM TO BE SOLVED: To provide an imaging lens composed of three lenses, which is compact and has satisfactory optical characteristics. SOLUTION: The imaging lens comprises a diaphragm S1, a menicus-shaped first lens L1 having positive powder and turning its convex surface to an object side, and a menicus-shaped second lens L2 having negative power and turning its convex surface to an image side, and a menicus-shaped third lens L3 having negative power and turning its convex surface to the object side, which are arranged in the order from the object side, and satisfies the conditional expressions (1) to (3): (1)-4.0<f1/f2<-0.1, (2) 4.0<f1/d1<7.0 and (3)-80.0<f2/d3<-20.0, wherein f1: the focal distance of the first lens L1, f2: the focal distance of the second lens L2, d1: the center thickness of the first lens L1 and d3: the center thickness of the second lens L2. COPYRIGHT: (C)2009,JPO&INPIT
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