Mgf2 optical thin film including amorphous silicon oxide binder, optical element provided with the same, and method for producing mgf2 optical thin film
AssigneeNikon Corporation
InventorsHITOSHI ISHIZAWA, Shunsuke Niisaka, Tsuyoshi Murata
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Abstract
An MgF2 optical thin film is formed on an optical surface of a base material. The MgF2 optical thin film includes MgF2 particles and an amorphous silicon oxide-based binder which exists on the surfaces of the MgF2 particles and between the MgF2 particles. Owing to this amorphous silicon oxide-based binder, the optical thin film can have high mechanical strength and high adhesion to the base material, while having excellent environment resistance and a lower refractive index.
Claims24
A method for producing an MgF2 optical thin film, comprising:
- preparing a sol solution, in which MgF2 minute particles are dispersed, by mixing a magnesium compound and a fluorine compound in a solvent;
- placing the sol solution in a vessel which is tightly closable and performing a pressurizing treatment and a heat treatment at the same time;
- preparing a binder solution which contains a component capable of forming an amorphous silicon oxide-based binder by a reaction, the amorphous silicon oxide-based binder being composed of amorphous silica;
- preparing a coating liquid by mixing the sol solution for which the pressurizing treatment and the heat treatment have been performed and the binder solution;
- forming a film by coating the coating liquid on a base material and by performing drying;
- and
- performing a heat treatment after forming the film, wherein the MgF2 minute particles are connected to one another by the amorphous silicon oxide-based binder.
A method for producing an MgF2 optical thin film, the method comprising:
- preparing a sol solution, in which MgF2 minute particles are dispersed, by mixing a magnesium compound and a fluorine compound in a solvent;
- placing the sol solution in a vessel which is tightly closable and performing a pressurizing treatment and a heat treatment at the same time;
- preparing a binder solution which contains a component capable of forming an amorphous silicon oxide-based binder by a reaction, the amorphous silicon oxide-based binder being composed of amorphous silica;
- forming a porous film by coating the sol solution, for which the pressurizing treatment and the heat treatment have been performed, on a base material and by performing drying;
- coating the binder solution on the porous film and impregnating the binder solution into the porous film;
- and
- performing a heat treatment after the impregnation,
- wherein the MgF2 minute particles are connected to one another by the amorphous silicon oxide-based binder.
Dependencies are inferred from the claim text.