Patent ID: 6999235

Claim:
A diffractive optical element, comprising a multilayer member composed of a plurality of layers each of which is made of an optical material, wherein: adjacent layers in the multilayer member are in contact with each other, and have different refractive indexes from each other; the multilayer member has therein one or more boundary face(s) between the contacted adjacent layers; an uneven pattern is formed on each of at least two faces of three or more faces including the one or more boundary face(s) and outer surfaces of the multilayer member, the uneven pattern causing transmitted light to undergo an intended diffraction; the uneven patterns formed on different faces have at least one of different shapes and different sizes from each other in a direction in which the layers of the multilayer member extend, such that the uneven patterns do not match each other when viewed in a direction that is orthogonal to the direction in which the layers extend; and a difference in the refractive indexes between all the adjacent layers on which the uneven patterns are formed is more than 0.01, and all the uneven patterns that are formed on the boundary face of the adjacent layers have heights that are set by taking into consideration the difference of the refractive indexes between the adjacent layers.