Patent ID: 8018662

Claim:
An imaging lens comprising: a first lens having positive refractive power; a second lens having negative refractive power; and a third lens having positive refractive power arranged in an order from an object side to an image side, wherein said first lens is formed in a shape so that both a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image side are positive, said second lens is formed in a shape so that a curvature radius of a surface thereof on the object side is negative and a curvature radius of a surface thereof on the image side is positive, said third lens is formed in a shape so that both a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image side are positive, and said first lens has a focal length f 1 , said second lens has a focal length f 2 , said third lens has a focal length f 3 , and a whole lens system has a focal length f so that the following conditional expressions are satisfied: f 1 >|f 2| −1.5 <f 1 /f 2≦−1.056 0.7 <f 3 /f≦ 1.039.