| 摘要 |
PROBLEM TO BE SOLVED: To provide a compact imaging lens which sufficiently responds to a request for a lower profile, has a brightness of F2.5 or less, and corrects various aberrations well while achieving a wide angle of view, at low cost.SOLUTION: The imaging lens includes, in order from the object side to the image side: a first lens L1 having a positive refractive power with a convex surface directed toward the object side; a second lens L2 having a negative refractive power with a concave surface directed toward the image side; a third lens L3 having a negative refractive power; a fourth lens L4 which has a negative refractive power and has a meniscus shape with a convex surface directed toward the image side, and whose both surfaces are aspherical; and a fifth lens L5 with a concave surface directed toward the image side, whose both surfaces are aspherical. The aspherical surface on the image side of the fifth lens has an inflection point at a position other than a position on the optical axis. The imaging lens satisfies the following conditional expressions (1) and (2): (1) TTL/2ih≤0.8, and (2) 20<&ngr;d1-&ngr;d2<50, where &ngr;d1 is the Abbe number of the first lens for the d-line, &ngr;d2 is the Abbe number of the second lens for the d-line, ih is the maximum image height, and TTL is the entire optical length.SELECTED DRAWING: Figure 1 |
