Glass substrate for magnetic disk and manufacturing method of the same
US8119267B2 · kind B2 · utility
5Cited by
4References
18Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Sep 26, 2008 |
| Grant date | Feb 21, 2012 |
| Priority date | — |
| Expiry date | Sep 26, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B5/8404
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A glass substrate for a magnetic disk of the invention is a disk-shaped glass substrate for a magnetic disk where the substrate has a main surface and end face and is subjected to chemical reinforcement treatment, and is characterized in that the penetration length in the uppermost-portion stress layer on the main surface is 49.1 μm or less, and that assuming that an angle between the main surface and compressive stress in the stress profile by a Babinet compensator method is θ, a value y of {12·t·ln(tan θ)+(49.1/t)} is the penetration length in the uppermost-portion stress layer or less.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.