Antireflection film and method of producing the same
AssigneeFUJIFILM Corporation
InventorHiroki Takahashi
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Abstract
An antireflection film substrate that is provided on a surface of a substrate includes a surface layer having an alumina hydrate as a main component. The surface layer has an uneven structure in which a volume proportion of the alumina hydrate per unit volume decreases in a direction from the substrate side to a surface side, and a period of apexes distributed on the uneven structure on the surface side is configured to be equal to or less than a wavelength of light of which reflection is to be suppressed.
Claims10
An antireflection film that is provided on a surface of a substrate, the film comprising:
- a surface layer having an alumina hydrate as a main component,
- wherein the surface layer has only an uneven structure in which a volume proportion of the alumina hydrate per unit volume decreases in a direction from a substrate side to a surface side, and a period of apexes distributed to the uneven structure on the surface side is configured to be equal to or less than a wavelength of light of which reflection is to be suppressed,
- an adhesion layer adjacent to the substrate side of the surface layer and formed of hydrogenated metal oxide, metal oxide, or metal fluoride is provided, and
- a thermal expansion coefficient value of the adhesion layer at a reference temperature of 25° C. is in a range of 0.65×10−6 to 19×10−6/K, and a difference in refractive index between the adhesion layer and the surface layer at an interface is 0.2 or more and 1.15 or less.
A method of producing an antireflection film comprising:
- subjecting a surface layer portion formed on a surface of a substrate and having aluminum or alumina as a main component to a hydrothermal treatment,
- wherein the surface layer portion is subjected to the hydrothermal treatment until the surface layer portion has only an uneven structure having an alumina hydrate as a main component,
- the uneven structure is a structure in which a volume proportion of the alumina hydrate which forms the surface layer portion per unit volume decreases in a direction from a substrate side to a surface side of the surface layer portion, and
- a multilayer film in which a plurality of hydrogenated silicon oxide layers having different refractive indexes formed by changing a hydrogen concentration in each thin film layer is laminated, is formed to be adjacent to the substrate side of the surface layer portion having the aluminum or alumina as a main component, before forming the surface layer portion.
Dependencies are inferred from the claim text.