| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass substrate for an information recording medium capable of holding strength required as the information recording medium while the deterioration of quality is suppressed, and to provide its manufacturing method. SOLUTION: The glass substrate 11 for the information recording medium has an outer peripheral reinforcement layer 17 and an inner peripheral reinforcement layer 18 which are compressive stress layers formed by chemical strengthening at an outer peripheral edge and an inner peripheral edge, respectively, and has no compressive stress layer on its main surface 13. The outer peripheral reinforcement layer 17 and the inner peripheral reinforcement layer 18 have depths of≥5μm and <30μm and compressive stress values of 19.6 to 147.1 MPa. The main surface 13 has a compressive stress value of≤4.9 MPa. COPYRIGHT: (C)2005,JPO&NCIPI
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