Patent ID: 8456761

Claim:
A lens system for imaging an object at an object side on an imaging surface at an image side, in the order from the object side to the image side, the lens system comprising: a first lens with negative refraction power, the first lens comprising a surface facing the image side, the surface facing the image side of the first lens comprising an optical portion; a second lens with positive refraction power; a third lens with positive refraction power; and an imaging plane for forming an image of the object, wherein the lens system satisfies the formulas: Y/Z <1.10; (1) G 1 R 1/ F 1<−3.10; and (2) G 2 R 2/ F 2>1.49. (3) wherein Y is a distance between an end point of the optical portion and a center point of the optical portion along a direction perpendicular an optical axis of the lens system, Z is a distance between the end point of the optical portion and the center point of the optical portion along the optical axis of the lens system, G 1 R 1 denotes the radius of curvature of a surface of the first lens which faces the object side, F 1 is the focal length of the first lens, and F 2 is the focal length of the second lens, G 2 R 2 denotes the radius of curvature of a surface of the second lens which faces the image side.