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US 7,611,639 B2Granted
Glass substrate for information recording medium and method for manufacturing same
AssigneeHoya Corporation
InventorsYasuhiro Saito, Toshiaki Hashimoto, Yuriko Kudoh
Life of this patent
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Abstract
A method for manufacturing a glass substrate having projections of the same height. The method includes forming a surface layer having a decreased chemical resistance on a glass plate, forming a texture including a plurality of projections having upper portions included in the surface layer, and selectively removing the surface layer.
Claims12
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.
1 more element
A method for manufacturing a glass substrate for an information recording medium, the manufacturing method comprising:
- preparing a disk-shaped glass plate having a predetermined composition and a predetermined chemical resistance;
- polishing the glass plate to form a smooth surface;
- chemically processing the smooth surface to form a surface layer having a composition differing from the predetermined composition, a chemical resistance that is lower than the predetermined chemical resistance, and a first thickness;
- forming a texture in a circumferential direction, the texture including a plurality of projections on the surface, each of the projections extending in a circumferential direction, wherein the projections extending over the surface layer and a lower layer adjacent to the surface layer are formed by removing the surface layer and the lower layer;
- and thereafter
- selectively removing only part of the plurality of projections included in the surface layer so that the plurality of projections have flat upper surfaces that are flush with each other, wherein a ratio of a maximum peak height, Rp, to an arithmetic mean roughness, Ra, of the surface layer is 8 or less.
3 more elements
Dependencies are inferred from the claim text.