GLASS SUBSTRATE FOR INFORMATION RECORDING MEDIUM, ITS MANUFACTURING PROCESS AND MAGNETIC RECORDING MEDIUM FOR RECORDING INFORMATION

摘要

PROBLEM TO BE SOLVED: To provide a glass substrate having an excellent surface smoothness and flatness and no bubbles, by finding and using a clarifier suitable for manufacturing a molded glass substrate for information recording media which serves as an alternative to conventional clarifiers, and its manufacturing process. SOLUTION: The manufacturing process comprises steps wherein a glass material composition composing the glass substrate is melted, the molten glass material composition is molded in a metal mold into the glass substrate, the molded glass substrate is taken out from the metal mold, and the obtained glass substrate is annealed. To the molten glass material composition, at least one compound chosen from the group consisting of CeO2, Pr6O11and Tb4O7is added as the clarifier. COPYRIGHT: (C)2004,JPO