| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a glass blank which is excellent in flatness, smoothness, and parallelism and of extremely thin, a manufacturing method of a substrate for a information recording medium using the glass blank and a manufacturing method of an information recording medium using the substrate for information recording medium. <P>SOLUTION: This medium is a disk type glass blank having a thin peripheral part and a thick center part, both planes of the thick part are convex (convex plane) than the thin part, also the thickness ratio of the thin part to the center part ( thickness of the thin peripheral part/thickness of the thick part) is in a range of 0.33-0.90. Also, a manufacturing method of the glass blank is provided. A manufacturing method of the substrate for information recording medium using the glass blank is provided. Also, a manufacturing method of the information recording medium in which information recording layer is formed in the substrate for information recording medium manufactured by the manufacturing method. <P>COPYRIGHT: (C)2004,JPO&NCIPI</p> |
