Diffractive optical element and optical system having the same
First Claim
1. A diffractive optical element comprising:
- a plurality of diffraction gratings made of different materials, wherein at least one of said plurality of diffraction gratings includes a region in which grating side surfaces are inclined, and inclinations thereof are different according to positions thereof and in accordance with an incident angle or emergent angle of a specified ray of light.
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Abstract
A diffractive optical element in which eclipse of rays at a grating side surface of a diffraction grating can be reduced is disclosed. In a diffractive optical element comprises a plurality of diffraction gratings made of different materials are laminated, at least one of the plurality of diffraction gratings includes a region in which the grating side surface inclines or a region in which edges thereof are shifted with respect to the edge of another diffraction grating adjacent thereto. The inclination or shift amount is different according to the positions thereof in a surface of the diffractive optical element in accordance with the incident angle or emergent angle of a specified ray such as a ray determined on the basis of an average value, gravity value, maximum value and minimum value obtained from the distribution of incident angle or emergent angle or the like, rays, etc.
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Citations
20 Claims
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1. A diffractive optical element comprising:
a plurality of diffraction gratings made of different materials, wherein at least one of said plurality of diffraction gratings includes a region in which grating side surfaces are inclined, and inclinations thereof are different according to positions thereof and in accordance with an incident angle or emergent angle of a specified ray of light. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 19)
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12. A diffractive optical element comprising:
a plurality of diffraction gratings made of different materials, wherein at least one of said plurality of diffraction gratings includes a region in which positions of grating edges thereof are shifted with respective to positions of grating edges of another diffraction grating adjacent thereto in an arranging direction of the grating portions and shift amounts thereof are different according to the positions thereof and in accordance with an incident angle or emergent angle of a specified ray. - View Dependent Claims (13, 14, 15, 16, 17, 18, 20)
Specification