Patent ID: 8269878

Claim:
An image pickup lens having a five-lens-element construction for forming an image of a subject onto a photoelectric conversion section of a solid-state image pickup element, the image pickup lens comprising, in order from an object side thereof: a first lens with a positive refractive power, comprising a convex surface facing the object side; a second lens with a negative refractive power, comprising a concave surface facing an image side, at least one surface of the second lens being aspheric; a third lens having at least one aspheric surface; a fourth lens with a positive refractive power, comprising a convex surface facing the image side; and a fifth lens with a negative refractive power, comprising a concave surface facing the image side, wherein the first to fifth lenses are separated from each other, wherein an image-side surface of the fourth lens is formed in an aspheric shape having positive refractive power which becomes smaller at a position on the surface, as the position becomes more distant from an optical axis of the fourth lens toward a peripheral portion, wherein an image-side surface of the fifth lens has an aspheric shape, and includes an inflection point at a position excluding an intersection point with an optical axis, and the image pickup lens satisfies the following conditional expressions: 20<v1 −v 2<70 (4) 1.60 <n 2<2.10 (5) L/ 2 Y< 1.1 (10) where v1 is an Abbe number of the first lens, v2 is an Abbe number of the second lens, n2 is a refractive index of the second lens for d-line, L is a distance along the optical axis from the lens surface arranged at the closest position to the object side in a total system of the image pickup lens to the focal point at the image side, and 2Y represents a diagonal length of an image pickup surface of the solid-state image pickup element.