Patent ID: 8879172
Filing Date: 2014-11-04
Classification: G02B

Abstract:
1. An imaging lens comprising: a first lens having positive refractive power; a second lens having negative refractive power; a third lens having positive refractive power; and a fourth lens having negative refractive power arranged in this order from an object side to an image plane side, wherein said first lens is formed in a shape so that a surface thereof on the object side is convex toward an object, said second lens is formed in a shape so that a surface thereof on the object side is concave toward the object and a surface thereof on the image plane side is convex toward the object, said third lens is formed in a shape so that both a surface thereof on the object side and a surface thereof on the image plane side are concave toward the object, said fourth lens is formed in a shape so that a surface thereof on the object side is concave toward the object and a surface thereof on the image plane side is convex toward the object, said fourth lens has a focal length f said third lens has a focal length f said second lens has the surface on the object side having a curvature radius R