Patent ID: 6980372

Claim:
An imaging lens comprising a first lens L 1 , an aperture diaphragm S 1 , a second lens L 2 , and a third lens L 3 , and constituted such that said first lens L 1 , aperture diaphragm S 1 , second lens L 2 , and third lens L 3 are arranged in succession from the object side to the image side, wherein said first lens L 1 is a lens having a positive refractive power and a meniscus shape in which the convex surface faces the object side, said second lens L 2 is a lens having a negative refractive power and a meniscus shape in which the convex surface faces the image side, and said third lens L 3 is a lens in which the convex surface faces the object side, both surfaces of said first lens L 1 and said second lens L 2 being aspheric, and at least one surface of said third lens L 3 being aspheric, and said imaging lens satisfying the following conditions: 0.35<r 1 /r 2 <0.45 (1) 0.07<D 2 /f<0.1 (2) 0.01<D 4 /f<0.04 (3) 1.00<d/f<1.30 (4) 0.3<b f /f<0.5 (5) where f is the combined focal length of the imaging lens, r 1 is the radius of curvature (axial radius of curvature) of the object-side surface of the first lens L 1 in the vicinity of the optical axis, r 2 is the radius of curvature (axial radius of curvature) of the image-side surface of the first lens L 1 in the vicinity of the optical axis, D 2 is the distance between the first lens L 1 and second lens L 2 , D 4 is the distance between the second lens L 2 and the third lens L 3 , d is the distance (atmospheric) from the object-side surface of the first lens L 1 to the imaging surface, and b f is the distance (atmospheric) from the image-side surface of the third lens L 3 to the imaging surface.