| 摘要 |
An imaging lens includes, in order from an object side, a first lens having a positive refractive power and having a meniscus shape with a convex surface directed to the object side thereof, a second lens having a concave object-side surface and a third lens having a negative refractive power in a vicinity of an optical axis. Each of the second and third lenses has at least one aspheric surface. The following conditional expressions are satisfied: <?in-line-formulae description="In-line Formulae" end="lead"?>0.8<f1/f<1.2 (1)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>11<|f2/f| (2)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>0.04<SA/Y<0.09 (3)<?in-line-formulae description="In-line Formulae" end="tail"?> <?in-line-formulae description="In-line Formulae" end="lead"?>TL/2Y<0.9 (4)<?in-line-formulae description="In-line Formulae" end="tail"?> where SA denotes the amount of sag of the object-side surface of the second lens in a position where a principal ray passes the maximum image height, Y denotes the maximum image height, and TL denotes a distance from an object-side surface of the first lens to an image formation position.
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