| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a method of manufacturing disk-like glass by which the disk-like glass having high circularity is manufactured using press molding, the disk-like glass obtained by the method and a substrate for the information recording medium, and a method of manufacturing the information recording medium. <P>SOLUTION: The method of manufacturing the disk-like glass having <1.2 mm maximum thickness includes a step for press-molding a molten glass lump using a lower mold and an upper mold to form the disk-like glass having an outer peripheral surface as a free surface. The disk-like glass having≤100μm circularity is obtained by controlling a separation mark occurring on the vicinity of surface of the molten glass lump by the separation of the molten glass to localize the separation mark remaining on the surface of the disk-like glass on the center part of the surface of the disk-like glass. The disk-like glass has <1.2 mm maximum thickness,≤100μm circularity and≤10μm flatness, wherein the outer peripheral surface is the free surface. The method of manufacturing the substrate for the disk-like information recording medium by processing the disk-like glass is provided. The method of manufacturing the information recording medium is provided. <P>COPYRIGHT: (C)2009,JPO&INPIT</p> |
