Diffractive optical element and method of manufacturing diffractive optical element
AssigneeCanon Kabushiki Kaisha
InventorKouichi Yonetani
Life of this patent
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Abstract
A diffractive optical element includes a first resin portion having a first diffraction grating and made of a first resin material, a second resin portion having a second diffraction grating formed to cover the first diffraction grating and made of a second resin material, and a transparent inorganic film formed on an optically effective surface, which is an interface between the first diffraction grating and the second diffraction grating, wherein a thickness of the transparent inorganic film at a grating tip of the first diffraction grating is thicker than a thickness of the transparent inorganic film at a grating surface other than the grating tip of the first diffraction grating.
Claims13
A diffractive optical element comprising:
- a first resin portion having a first diffraction grating and made of a first resin material;
- a second resin portion having a second diffraction grating formed to cover the first diffraction grating and made of a second resin material;
- and
- a transparent inorganic film formed on an optically effective surface, which is an interface between the first diffraction grating and the second diffraction grating,
- wherein a thickness of the transparent inorganic film at a grating tip of the first diffraction grating, taken along a grating height of the first diffraction grating, is thicker than a thickness of the transparent inorganic film at a grating surface other than the grating tip of the first diffraction grating, taken in a normal direction to the grating surface.
A method of manufacturing a diffractive optical element, comprising:
- injection molding a thermoplastic resin to form a first resin portion having a first diffraction grating and made of the thermoplastic resin;
- forming a transparent inorganic film on the first diffraction grating;
- and
- forming a photocurable resin on the transparent inorganic film to form a second resin portion having a second diffraction grating and made of the photocurable resin,
- wherein forming the transparent inorganic film forms the transparent inorganic film such that a thickness of the transparent inorganic film at a grating tip of the first diffraction grating, taken along a grating height of the first diffraction grating, is thicker than a thickness of the transparent inorganic film at a grating surface other than the grating tip of the first diffraction grating, taken in a normal direction to the grating surface.
Dependencies are inferred from the claim text.