Patent ID: 7339752
Filing Date: 2008-03-04
Classification: G02B

Abstract:
1. An image pick-up lens system comprising, from an object side to an image side: an aperture stop; and a lens having a concave first surface on the object side and a convex second surface on the image side, and satisfying the following condition: wherein, R1 is an absolute value of a radius of curvature of a vertex of the first surface of the lens on the object side, and R2 is an absolute value of a radius of curvature of a vertex of the second surface of the lens on the image side; and a diffraction grating provided at the second surface of the lens and satisfying the following condition: wherein, f is a focal length of the image pick-up lens system, and C 2 is a power phase coefficient of a phase function of the diffraction grating of the second surface of the lens.