DIFFRACTIVE IMAGING LENS, DIFFRACTIVE IMAGING LENS OPTICAL SYSTEM, AND IMAGING APPARATUS USING THE DIFFRACTIVE IMAGING LENS OPTICAL SYSTEM

摘要

A diffractive imaging lens 10 includes a surface on which a diffraction grating pattern is formed. The diffraction grating pattern is formed of a plurality of steps formed concentrically with an optical axis (25) at a center. The diffraction grating pattern is formed such that a first portion where amounts (di) of the steps are substantially the same in a radial direction of concentric circles and a second portion, outside of the first portion, where amounts (di) of the steps decrease with distance from the optical axis 25 are provided, or such that the amounts (di) of the steps decrease with distance from the optical axis 25 over the entire diffraction grating pattern.