DIFFRACTION OPTICAL ELEMENT AND MANUFACTURING METHOD THEREOF

摘要

PROBLEM TO BE SOLVED: To provide a diffraction optical element in which diffraction efficiency is improved and a pickup function is improved by shaping a spherical wave-shaped wave resulting from the boundary condition of a blaze side wall into a wave in a main diffraction direction while suppressing the occurrence of the spherical wave- shaped wave and further preventing the surface reflection of a lens, and to provide a method for manufacturing the diffraction optical element.

SOLUTION: The side wall part 3a of a blaze 3 is provided with an absorber or a coating layer 3aa formed from a metal material, and the occurrence of the spherical wave-shaped wave is suppressed by stopping the continuity of light waves between the outer side and inner side of the side wall part 3a. A projecting part 3d having a boundary surface 3da is provided in the vicinity (position for emitting spherical wave-shaped wave in detail) of the blaze top of an inclination part 3b to shape a spherical wave-shaped wave having an inclination into a wave heading for a main diffraction direction. Hole parts 3db and 3bb for preventing surface reflection are further provided on the boundary surface 3da of the projecting part 3d and the boundary surface of the inclination part 3b to prevent surface reflection.

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