Patent ID: 7957063

Claim:
A diffractive optical device that comprises a first to third diffractive device elements composed of resins of different materials, and that has a laminated structure, in which the second diffractive device element is bonded between the first diffractive device element and the third diffractive element, characterized in that a first diffractive optical surface is formed by adhering a diffraction grating groove, which is formed on the first diffractive device element, and a diffracting grating groove, which is formed on the second diffractive device element, on a bonding surface of the first diffractive device element and the second diffractive device element, a second diffractive optical surface is formed by adhering a diffraction grating groove, which is formed on the second diffractive device element, and a diffraction grating groove, which is formed on the third diffractive device element, on a bonding surface of the second diffractive device element and the third diffractive device element, both the non-bonded surface of the first diffractive device element and the non-bonded surface of the third diffractive device element are composed of continuous surfaces, and where a refractive index of the first diffractive device element with the d-line is n 1 , a refractive index of the second diffractive device element with the d-line is n 2 , a refractive index of the third diffractive device element with the d-line is n 3 , an Abbe number of the first diffractive device element is νd 1 , an Abbe number of the second diffractive device element is νd 2 , and an Abbe number of the third diffractive device element is νd 3 , at least one of the following expressions is satisfied −0.001425<( n 1− n 2)/( νd 1− νd 2) −0.001425<( n 2− n 3)/( νd 2− νd 3).