Substrate members for recording disks and process for producing same
US4659606A · kind A · utility
31Cited by
4References
17Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 26, 1985 |
| Grant date | Apr 21, 1987 |
| Priority date | — |
| Expiry date | Apr 26, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/265
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A substrate member for recording disks comprises a sputtered film of Al.sub.2 O.sub.3, SiO.sub.2 and/or Si.sub.3 N.sub.4 on the surface of an alumina base ceramic material having therein micropores of no more than 5 microns and a relative theoretical density of no less than 96% said sputtered film having a surface roughness of no more than 80 angstroms, being substantially pore-free and strain-free on the surface, and having a thickness of 0.3 to 30 microns.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.