Diffractive optical element and method for manufacturing same

An element comprising:

• a glass lens substrate;
• and
• a resin layer composed of a photo-curable resin disposed on the glass lens substrate, the resin layer having a diffraction grating shape including a plurality of inclined surfaces and wall surfaces,
• wherein the refractive index of the resin layer varies depending on a thickness of the resin layer with respect to all the inclined surfaces of the diffraction grating shape, and the variation of the refractive index is based on light that applies in a direction perpendicular to the inclined surface or deviated from the perpendicular direction toward a thinner portion of the resin layer with respect to each inclined surface.

An element comprising:

• a first glass lens substrate;
• a second glass lens substrate;
• and
• a first resin layer and a second resin layer disposed and laminated between the first glass lens substrate and the second glass lens substrate, the first resin layer and the second resin layer each being composed of a photo-curable resin, a boundary surface between the first resin layer and the second resin layer having a diffraction grating shape including a plurality of inclined surfaces and wall surfaces,
• wherein the refractive index of the second resin layer varies depending on a thickness of the resin layer with respect to all the inclined surfaces of the diffraction grating shape, and the variation of the refractive index is based on light that applies in a direction substantially perpendicular to the inclined surface or deviated from the perpendicular direction toward the thinner portion of the resin layer with respect to each inclined surface.

A method for manufacturing an element including a glass lens substrate and a resin layer disposed on the glass lens substrate, the resin layer having a diffraction grating shape, the method comprising:

• supplying a photo-curable resin material to a molding die having the diffraction grating shape including a plurality of inclined surfaces and wall surfaces;
• bringing the glass lens substrate into contact with the photo-curable resin material supplied to the molding die to fill a space between the molding die and the glass lens substrate with the photo-curable resin material;
• curing the photo-curable resin material by applying light in a direction substantially perpendicular to the inclined surfaces of the diffraction grating shape of the molding die or in a direction deviated from the perpendicular direction toward the thinner portion of the resin layer with respect to each inclined surface to integrate the glass lens substrate with the resin layer having the diffraction grating shape;
• and
• releasing the glass lens substrate and the resin layer, which have been integrated together, from the molding die.

A method for manufacturing an element including a first glass lens substrate, a second glass lens substrate, and a first resin layer and a second resin layer disposed and laminated between the first glass lens substrate and the second glass lens substrate, the method comprising:

• supplying a first photo-curable resin material to a molding die having a diffraction grating shape including a plurality of inclined surfaces and wall surfaces;
• bringing the first glass lens substrate into contact with the first photo-curable resin material supplied to the molding die to fill a space between the molding die and the first glass lens substrate with the first photo-curable resin material;
• curing the first photo-curable resin material by applying light to integrate the first glass lens substrate with the first resin layer;
• and
• releasing the first glass lens substrate and the first resin layer, which have been integrated together, from the molding die;
• supplying a second photo-curable resin material to the second glass lens substrate;
• bringing the first glass lens substrate and the first resin layer, which have been integrated together, into contact with the second photo-curable resin material supplied to the second glass lens substrate to fill a space between the first resin layer and the second glass substrate with the second photo-curable resin material;
• and
• curing the second photo-curable resin material by applying light in a direction substantially perpendicular to the inclined surfaces or in a direction deviated from the perpendicular direction toward the thinner portion of the resin layer with respect to each inclined surface to integrate the first glass lens substrate and the first resin layer with the second glass lens substrate and the second resin layer.