Patent ID: 7755854
Filing Date: 2010-07-13
Classification: G02B

Abstract:
1. An image pickup lens for forming an image of an object on a photoelectrical converter of a solid-state image pickup element, the image pickup lens comprising, in order from an object side thereof: an aperture stop; a first lens having a positive refractive power; a second lens having a negative refractive power; a third lens having a positive refractive power; and a fourth lens having a negative refractive power and a biconcave shape and comprising a surface in an aspheric shape, wherein the image pickup lens satisfies following expressions: where f1 is a focal length of the first lens, f3 is a focal length of the third lens, f is a focal length of the total system of the image pickup lens, r7 is a curvature radius of a surface of the fourth lens facing the object side, and r8 is a curvature radius of a surface of the fourth lens facing an image side.