Production method for non-alkali glass

Abstract

A non-alkali glass production method, in which a glass raw material is inserted into a melting furnace, heated to a temperature of 1,350°-1,750°C and changed into molten glass, after which the molten glass is formed into a sheet, using the float method. Both heating by burner flame, and electrical heating of the molten glass by a heating electrode arranged so as to be immersed in the molten glass inside the melting furnace, are used for the heating in the melting furnace. The glass raw material and the refractory material configuring the melting furnace are selected such that Rb>Rg, when the electrical resistivity of the molten glass at 1,350°C is Rg (Omegacm), and the electrical resistivity of the refractory material at 1,350°C is Rb (Omegacm).

Description

technical field [0001] This invention relates to the manufacturing method of the alkali-free glass suitable as the substrate glass for various displays, and the substrate glass for photomasks. [0002] Hereinafter, in this specification, when referred to as "alkali-free", it means an alkali metal oxide (Li 2 O, Na 2 O, K 2 The content of O) is 2000 ppm or less. Background technique [0003] Conventionally, various substrate glasses for displays, especially substrate glasses formed with a metal or oxide thin film on the surface, have been required to have the following characteristics. [0004] (1) If alkali metal oxides are contained, the alkali metal ions will diffuse into the film and deteriorate the film properties. Therefore, the content of alkali metal oxides is required to be extremely low, specifically, the content of alkali metal oxides is required to be 2000ppm the following. [0005] (2) In order to minimize the deformation of the glass and the shrinkage (ther...

AI Technical Summary

Problems solved by technology

As a heating method for melting raw materials, the raw materials are generally heated to a predetermined temperature by heating with a combustion flame of a burner arranged above the melting furnace, but in the case of heating to a high temperature of 1350 to 1750°C, a melting furnace is formed. The refractory may be corroded

If the corrosion of the refractory material occurs, the components of the refractory material will melt into the molten glass, resulting in a decrease in the quality of the manufactured glass, which becomes a problem

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