DIFFRACTION-GRATING LENS, AND IMAGE-CAPTURING OPTICAL SYSTEM AND IMAGE-CAPTURING DEVICE USING SAID LENS

摘要

A diffraction-grating lens has positive power and includes a lens base (11) on the surface of which a diffraction grating is formed, and an optical adjustment film (15) that is disposed on a diffraction grating surface of the lens base provided with the diffraction grating. The optical adjustment film is made of a material having a higher refractive index and lower wavelength dispersibility of the refractive index than those of a material of the lens base. When a reference position (17) is defined as a position (Rr) that is 70% of an effective radius (Re) measured from the center of the diffraction grating, the diffraction grating surface in the reference position is substantially parallel to a surface perpendicular to an optical axis (13). With this configuration, it is possible to provide a diffraction-grating lens and an image-capturing device that can reduce the generation of unnecessary diffraction light.

主权项

1. A diffraction-grating lens having positive power and comprising:
a lens base on a surface of which a diffraction grating is formed; and an optical adjustment film that is disposed on a diffraction grating surface of the lens base provided with the diffraction grating, wherein the optical adjustment film is made of a material having a higher refractive index and lower wavelength dispersibility of the refractive index than those of a material of the lens base, and wherein when a reference position is defined as a position that is 70% of an effective radius measured from a center of the diffraction grating, the diffraction grating surface in the reference position is substantially parallel to a surface perpendicular to an optical axis.