| US 7,611,639 B2 | ||
| Glass substrate for information recording medium and method for manufacturing same | ||
| Yasuhiro Saito, Osaka (Japan); Toshiaki Hashimoto, Osaka (Japan); and Yuriko Kudoh, Osaka (Japan) | ||
| Assigned to Hoya Corporation, Tokyo (Japan) | ||
| Appl. No. 10/532,538 PCT Filed Oct. 22, 2003, PCT No. PCT/JP03/13461 § 371(c)(1), (2), (4) Date Aug. 17, 2005, PCT Pub. No. WO2004/042709, PCT Pub. Date May 21, 2004. |
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| Claims priority of application No. 2002-308812 (JP), filed on Oct. 23, 2002. | ||
| Prior Publication US 2006/0003170 A1, Jan. 05, 2006 | ||
| This patent is subject to a terminal disclaimer. | ||
| Int. Cl. C03C 15/00 (2006.01); G11B 5/84 (2006.01); G11B 7/26 (2006.01) | ||
| U.S. Cl. 216—22 [216/24; 216/83; 216/88; 216/89; 216/97] | 12 Claims |
| 1. A method for manufacturing a glass substrate for an information recording medium, the manufacturing method comprising:
forming a surface layer on a surface of a disk-shaped glass plate having a predetermined composition and a predetermined chemical
resistance, with the surface layer having a composition differing from the predetermined composition and a chemical resistance
that is lower than the predetermined chemical resistance;
scrubbing the surface in a circumferential direction with an abrasive and a scrub member to form a texture including a plurality
of projections each extending in a circumferential direction of the surface, the scrubbing forming the projections extending
over the surface layer and a lower layer adjacent to the surface layer by removing the surface layer and the lower layer;
and thereafter
selectively removing an upper portion of the projections included in the surface layer with an etching liquid, wherein a ratio
of a maximum peak height, Rp, to an arithmetic mean roughness, Ra, of the surface layer is 8 or less.
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