Patent ID: 8659839

Claim:
An imaging lens comprising a single joint type compound lens for forming a subject image to a photoelectric conversion section of a solid-state image sensing element, the joint type compound lens configured to include, in an order from an object side thereof: a first lens having a plane concave lens concave toward the object side; a second lens which is a parallel plate element; and a third lens having a plane convex lens convex toward an image side, wherein the first lens and the third lens are formed of energy curable resin material; the parallel plate element is formed of glass material; the first lens and the second lens are directly or indirectly joint; and the second lens and the third lens are directly or indirectly joint, wherein the following conditional expression is satisfied −1.5 <rL 11 /f<− 5.0 (1) where, f is a focal length of a whole system of the imaging lens and rL11 is a local curvature radius of an object side surface of the first lens calculated by the following formula: rL 11={( h 1)2+( s 1)2}/(2 s 1) where h1 is 1/10 of an effective radius at an object side surface of the first lens, and s1 is an amount of a displacement in a parallel direction of an optical axis from a surface apex at a height h1 of the object side surface of the first lens.