Patent attributes
A laminated diffractive optical element including a colorant-containing first layer having a diffraction grating surface with a grating height X and a second layer closely stacked on the diffraction grating surface of the first layer, wherein the relation of internal transmittances Tλ, a and Tλ, b of a material (a) for forming the first layer and a material (b) for forming the second layer satisfies the following (Formula 1) and the relation of the maximum and minimum internal transmittances Tλ, MAX and Tλ, MIN of the laminated diffractive optical element satisfies the following Formula (2):2.0%≦|Tλ, a−Tλ, b| (Formula 1)Tλ, MAX−Tλ, MIN≦8.0% (Formula 2)This reduces shading on the image surface resulting from the difference in transmittance of the optical element to provide a laminated diffractive optical element having reduced variation in transmittance.
