Patent ID: 7294293

Claim:
A method for manufacturing a diffraction optical element, comprising: a first step of supplying a photocurable resin onto a surface of a light-transmitting molding die in which a grating pattern is formed on the surface; a second step of irradiating the photocurable resin with light in a first wavelength band through the molding die so as to cure a first part of the photocurable resin, which said first part forms a diffraction grating in contact with the molding die; a third step of irradiating the photocurable resin with light in a second wavelength band, the light in the second wavelength band being longer than the light in the first wavelength band, so as to cure the photocurable resin not cured in the second step; and a fourth step of removing the cured resin from the molding die, wherein the light in the first wavelength band used to cure the first part that forms the diffraction grating is not transmittable through the entirety of the photocurable resin.