Patent ID: 8576499

Claim:
An imaging lens comprising: an aperture stop: a first lens having a positive refractive power: a second lens having a negative refractive power which is formed in a concave shape on both sides thereof; a third lens having a positive refractive power which is formed in a meniscus shape in which a concave surface is directed toward the side of an object; and a fourth lens having a negative refractive power in which a convex surface is directed toward the object side, which are sequentially disposed from the object side to the image side, wherein the imaging lens satisfies the following conditional expressions (1), (2), (3) and (4): 0.40< f 1/| f 2|<.80 (1) 0.10< f/f 3<080 (2) 0.20< f/|f 4|<1.00 (3) vd 1− vd 2>25 (4) where f 1 is a focal length of the first lens, f 2 is a focal length of the second lens, f 3 is a focal length of the third lens, f 4 is a focal length of the fourth lens, f is a focal length of an entire lens system, vd 1 is an Abbe number of the first lens, and vd 2 is an Abbe number of the second lens, and wherein the imaging lens satisfies the following conditional expression (5): 1.50< R 6/ R 7<4.00 (5) where R 6 is a paraxial curvature radius of the surface on the object side of the third lens, and R 7 is a paraxial curvature radius of a surface on the image side of the third lens.