Patent ID: 8184383
Filing Date: 2012-05-22
Classification: G02B

Abstract:
1. An imaging lens comprising, in order from an object side; a stop; a first lens including a positive lens having a convex surface directed to the object side; a second lens that includes, near an optical axis, a negative meniscus shape with a concave surface directed to an image side; a third lens that has, near the optical axis, a meniscus shape or a flat convex shape with a convex surface directed to the image side; and a fourth lens that includes a negative lens having, near the optical axis, a concave surface directed to the image side, wherein a surface of the second lens located on the object side has an aspheric shape having at least one inflection point, wherein surfaces of the third lens each has aspheric shape including at least one inflection point, wherein a sag amount of each of the surfaces of the third lens at the terminal end part of a periphery within an effective diameter increases with a surface height from the optical axis and, conditional expressions are satisfied: where D D νd νd f f f is a focal length of a whole system.