Patent ID: 7009783

Claim:
A pickup lens, comprising a first lens L 1 , having a meniscus shape with concave surface on the object side, and having negative refractive power; an aperture diaphragm S; a second lens L 2 , with convex surfaces on both the object side and the image side, and having positive refractive power; a third lens L 3 , with concave surfaces on both the object side and the image side, and having negative refractive power; and a fourth lens L 4 , with convex surfaces on both the object side and the image side, and having positive refractive power; and configured by arranging in order, from the object side, the first lens L 1 , the aperture diaphragm S, the second lens L 2 , the third lens L 3 , and the fourth lens L 4 ; and wherein at least three lens surfaces among the surfaces of said first through fourth lenses are aspherical, and the following conditions are satisfied: +5.0<( r 2 +r 1 )/( r 2 −r 1 )<+7.0 (1) 0.15f<d 1 <0.3f (2) where r 1 is the radius of curvature of the object-side surface of the first lens in the vicinity of the optical axis (axial radius of curvature); r 2 is the radius of curvature of the image-side surface of the first lens in the vicinity of the optical axis (axial radius of curvature); d 1 is the thickness of the first lens; and, f is the focal length of the entire system (the combined focal length of the lens system comprising the first, second, third, and fourth lenses).