Glass substrate for recording medium
OwnerToshiharu Mori, Hideki Kawai +4inventors
InventorsToshiharu Mori, Hideki Kawai, Akira Sugimoto, Hiroshi Yuki, Hideki Nagata, Kazuhiko Ishimaru
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Abstract
A polished glass disk medium substrate table for use as a substrate for a hard disk, a hard disk containing the substrate and methods for making the substrate. Glass forming raw materials are formed into a disk having a diameter between about 70 mm and about mm, a thickness between about 0.7 mm and about 0.9 mm, a flutter of less than 90 nm at 10,000 rpm.
Claims34
A polished glass disk medium substrate suitable for use as a substrate for a disk medium said disk having a diameter between about 70 mm and about 90 mm, a thickness between about 0.7 mm and about 0.9 mm, and a flutter of less than about 90 nm at 10,000 rpm.
A method of making a glass disk medium substrate comprising:
- heating glass forming raw materials to a temperature sufficiently high to melt the raw materials;
- forming a disk medium substrate;
- and crystallizing the disk medium substrate, wherein said crystallizing comprises heating the disk medium substrate to a temperature, T1, between about 730 and 770° C.;
- maintaining the temperature T1 for a time between about 2 and about 7 hours;
- heating the glass forming raw materials to a temperature, T2, between about 820 and 900° C.;
- and maintaining the temperature T2 for a time between about 3 and about 9 hours.
Dependencies are inferred from the claim text.