| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for mass-producing glass blanks for substrates for information recording media; and to provide methods for manufacturing the substrates for information recording media and the information recording media. SOLUTION: In press molding, a prescribed amount of glass gob in a softened state is pressed until the distance between the molding faces of a couple of pressing molds becomes a prescribed value. A couple of main surfaces and the outer peripheral face of a glass blank are formed by transferring the outer periphery-restricting face to the whole outer periphery of glass by extending the glass along opposing two molding faces of the pressing molds by pressing the glass gob. A thick part is formed at the outer edge of the glass blank by infiltrating the extended gas into a portion of a space for forming the thick part provided at the outer peripheral part of the molding face. The filling degree of the glass into the space for forming the thick part is changed in accordance with the variation of the amount of glass gob supplied at every press molding. The variation width of the amount of glass gob supplied at every press molding and the volume of the space for forming the thick part are set within a range that the thick part is formed, but the glass is not filled in an amount higher than the volume of the space for forming the thick part. The methods for manufacturing the substrates for the information recording media and the information recording media are also provided. COPYRIGHT: (C)2010,JPO&INPIT |
