DIFFRACTIVE OPTICAL ELEMENT AND IMAGING DEVICE AND ILLUMINATING DEVICE USING SAME

摘要

To provide a highly workable diffractive optical element which realizes a high refractive index and a low wavelength dispersiveness well balanced with each other and which exhibits high heat resistance and high endurance against temperature changes, a diffractive optical element includes a base member including a diffraction grating formed on a surface thereof and a protective film provided on the surface of the base member where the diffraction grating is formed, wherein the base member is composed of a silsesquioxane resin material or a dendrimer material which has a first refractive index and a first Abbe number and wherein the protective film is composed of a silicone resin material which has a second refractive index smaller than the first refractive index and a second Abbe number smaller than the first Abbe number.

主权项

1. A diffractive optical element, comprising:
a base member including a diffraction grating formed on a surface thereof; and a protective film provided on the surface of the base member where the diffraction grating is formed; wherein the base member is composed of a silsesquioxane resin material or a dendrimer material which has a first refractive index and a first Abbe number; and wherein the protective film is composed of a silicone resin material which has a second refractive index smaller than the first refractive index and a second Abbe number smaller than the first Abbe number.