Patent ID: 8482865

Claim:
An image lens for imaging an object on an image plane, in the order from the object side to the image side thereof, comprising: a first lens having positive refraction power and comprising a first surface facing the object side and a second surface facing the image side; and a second lens having negative refraction power and comprising a third surface facing the object side and a fourth surface facing the image side; wherein the image lens satisfies the following formulas: FB/TTL> 0.23; (1) G 1 R 1 /F 1>1.93; (2) Z/Y> 0.27; (3) Z/T< 0.89; and (4) G 2 R 1 /F 2 <G 2 R 2 /F 2 <G 1 R 2 /F 2; (5) wherein FB is a distance between the fourth surface and the image plane along an optical axis of the image lens, TTL is a total length from an aperture stop to the image plane, Z is a distance from a central point of the fourth surface to the fourth surface along the optical axis of the image lens, Y is a distance from the central point of the fourth surface to an edge of the fourth surface along a direction perpendicular to the optical axis of the image lens, T is a thickness of the second lens along the optical axis, G 2 R 1 is a curvature radius of the third surface, G 2 R 2 is a curvature radius of the fourth surface, G 1 R 2 is a curvature radius of the second surface, and F 2 is a focal length of the second lens.