Patent ID: 9557454
Date: 2017-01-31
CPC Classifications: B29D,G02B

Claim:
1. A laminated diffraction optical element comprising: a substrate; and a resin layer provided on the substrate and including an optically effective portion and an optically non-effective outer portion adjacent to the optically effective portion, wherein the optically non-effective outer portion in the resin layer includes at least a continuous first shape such that a layer thickness decreases when extending toward an outer periphery of the substrate and a second shape, adjacent to the first shape, such that the layer thickness increases when extending toward the outer periphery of the substrate, wherein an angle formed between a straight line connecting both ends of the continuous first shape such that the layer thickness decreases and a tangent to a surface of the substrate at a point opposite to an end closer to the surface of the substrate is within a range of 20 to 60 degrees, wherein the optically non-effective outer portion in the resin layer includes repetitive pairs of the continuous first shape such that the layer thickness decreases when extending toward the outer periphery of the substrate and the second shape, adjacent to the first shape, such that the layer thickness increases when extending toward the outer periphery of the substrate, wherein the number of the repetitive pairs is within a range of 2 to 10, and wherein the repetitive pairs are concentrically provided.