| 摘要 |
PROBLEM TO BE SOLVED: To provide a glass substrate for magnetic recording medium, capable of preventing breakage of a magnetic disk. SOLUTION: In the doughnut shaped glass substrate for magnetic recording medium having two main surfaces 101a and 101b, an outer periphery edge face 102 and inner periphery edge face, two first chamfered faces 104a and 104b connecting the two main surfaces and outer periphery edge face, and two second chamfered faces connecting the two main surfaces and inner periphery edge face, the first chamfered faces 104a and 104b and second chamfered faces consist of a conical surface 104a" and ring curved surface 104a' connected with each other and a percentage ratio of an outline length d1 of the ring curved surface 104a' to an outline length L of the chamfered face in the cross section of the glass substrate is equal to≥20%. A boundary part of the conical surface 104a" and ring curved surface 104a' is continuous. COPYRIGHT: (C)2011,JPO&INPIT
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