Imaging lens

摘要

A compact low-priced imaging lens which offers a field of view of about 180 degrees and high optical performance. The imaging lens for a solid-state image sensor includes, in order from an object side to an image side, a first lens with negative refractive power having a convex object-side surface and an aspheric image-side surface; a second lens with negative refractive power as a double-sided aspheric lens having a concave surface on the image side; a third lens with positive refractive power; an aperture stop; and a fourth lens with positive refractive power. The first and second lenses are made of plastic material. The imaging lens satisfies conditional expressions (1) and (2) below:
−65.0

主权项

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:
−50.76≦f1/f≦−21.63  (1b)0.06≦f2/f1≦0.12  (2b)6.09≦f3/f≦7.64  (3b)2.03≦f4/f≦2.41  (4b)18.01≦TTL/f≦20.34  (5b) 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.