Patent ID: 8477435

Claim:
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 positive refractive power, said first to fourth lenses being arranged in an order from an object side to an image plane side, wherein said first lens is formed in a shape so that a curvature radius of a surface thereof on the object side is positive, said second lens is formed in a shape so that a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image plane side are both positive, said third lens is formed in a shape so that a curvature radius of a surface thereof on the object side and a curvature radius of a surface thereof on the image plane side are both negative, and said fourth lens is formed in a shape so that a curvature radius of a surface thereof on the object side is positive, and a curvature radius of a surface thereof on the image plane side is negative.