Patent ID: 9366791
Filing Date: 2016-06-14
CPC Classification: C23C,G02B

Claim Text:
1. A manufacturing method for a diffractive optical element, the manufacturing method comprising: forming multiple grating portions including grating optical effective surfaces for transmitting the incident light and grating wall surfaces for shielding the incident light continuously on a base substrate; forming an Al layer on the grating wall surfaces and the grating optical effective surfaces such that the density and film thickness of the Al layer formed on the grating wall surfaces are different from those of the Al layer formed on the grating optical effective surfaces; and performing oxidation treatment of the Al layer under a condition that an oxidation speed is faster in the Al layer formed on the grating optical effective surfaces than in the Al layer formed on the grating wall surfaces, thereby converting the Al layer formed on the grating optical effective surfaces into an Al wherein the oxidation treatment is performed to form an Al layer on the grating wall surfaces to have a film density of 2.0 g/cm