Patent ID: 9541735
Date: 2017-01-10
CPC Classifications: G02B

Claim:
1. An imaging lens in which elements are arranged in order from an object side to an image side, comprising: a first lens having negative refractive power, a convex surface on the object side, and an aspheric surface on the image side; a second lens as a double-sided aspheric lens having negative refractive power and a concave surface on the image side; a third lens having positive refractive power; an aperture stop; and a fourth lens having positive refractive power, wherein the first lens and the second lens are made of plastic material; and conditional expressions (1b), (2b), (3b), (4b), and (5b) below are satisfied: where f: focal length of an overall optical system of the imaging lens f1: focal length of the first lens f2: focal length of the second lens f3: focal length of the third lens f4: focal length of the fourth lens TTL: distance on an optical axis from the object side surface of the first lens to an image plane.