| 摘要 |
PURPOSE:To readily produce optical glass having refractive index continuously changing, by molding melt containing plural rare earth element oxides, etc., and an oxide having paramagnetism in a magnetic field into a given shape and cooling the molded glass to <=glass transition temperature. CONSTITUTION:Raw materials are blended in such a way that prepared glass has a composition consisting of 5-70wt% La2O3, 10-90wt% B2O3, <=20wt% at least one of Y2O and Gd2O3 and 1-10wt% at least one of Fe2O3, NiO and Cr2O3 to give a batch. The batch is heated, melted and clarified to give uniform melt. The melt is molded into a given shape in a magnetic field and cooled to the glass transition temperature. The oxide contained in the composition which is a paramagnetic substance causes magnetic separation and changes dielectric constant and refractive index continuously by carrying out molding process in the magnetic field. Optical glass having continuous refractive index changing continuously is readily obtained without using plural kinds of glass having different refractive indexes and plural melts having different compositions. |
