Patent ID: 7911715
Filing Date: 2011-03-22
Classification: G02B

Abstract:
1. An imaging lens comprising in order from an object side: a first lens that includes a positive lens having a convex surface directed to the object side; a stop; a second lens that includes a positive lens having a convex surface directed to an image side; a third lens that includes a negative meniscus lens with a concave surface directed to the object side; and a fourth lens that includes, near an optical axis, a positive meniscus shape with a convex surface directed to the object side, wherein an air space between the second lens and the third lens is smaller in a periphery than near the optical axis, and the following conditional expressions are satisfied: where f 1 is a focal length of the first lens, f 2 is a focal length of the second lens, f 3 is a focal length of the third lens, and f is an focal length of the whole lens system.