Patent ID: 7667902

Claim:
A pickup lens, mounted in an image pickup device comprising a solid-state image pickup element, a length of the diagonal line in the rectangular light-receiving area of which is 2Y, comprising an aperture diaphragm S 1 , a first lens L 1 , a second lens L 2 , and a third lens L 3 , and being configured by arranging in order, from an object side to an image side, said aperture diaphragm S 1 , said first lens L 1 , said second lens L 2 , and said third lens L 3 , and wherein said first lens L 1 is a lens having positive refractive power, in a meniscus shape with a convex surface directed toward the object side; said second lens L 2 is a lens having negative refractive power, in a meniscus shape with a convex surface directed toward the image side; said third lens L 3 is a lens having negative refractive power, in a meniscus shape with a convex surface directed toward the object side; both surfaces of said first lens L 1 are aspherical, both surfaces of said second lens L 2 are aspherical, and both surfaces of said third lens L 3 are aspherical; and the following conditions are satisfied: 0.57 <f 1 /f< 0.65 (1) 0.01 ≦r 2 /r 3 ≦0.05 (2) 0.1 ≦d 3 /f< 0.15 (3) 0.6 <L/ 2 Y< 0.9 (4) where, f: combined focal length of said pickup lens f 1 : focal length of said first lens L 1 r 2 : radius of curvature, at the optical axis, of the object-side surface of said first lens L 1 in the vicinity of the optical axis r 3 : radius of curvature, at the optical axis, of the image-side surface of said first lens L 1 in the vicinity of the optical axis d 3 : interval between said first lens L 1 and said second lens L 2 along the optical axis L: optical length, which is a distance in air along the optical axis from the object-side surface of said first lens L 1 to the image plane 2Y: length of a diagonal line of the rectangular light-receiving area of the solid-state image pickup element installed in the image plane of said pickup lens.