Disc media
US4552820A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 25, 1984 |
| Grant date | Nov 12, 1985 |
| Priority date | — |
| Expiry date | Apr 25, 2004 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/12944
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A thin-film disc fabrication method and structure contemplates a sputtered undercoat. An aluminum base is subjected to a fine polishing step, and a relatively thin undercoat is deposited by sputtering. The preferred undercoat is a 0.3-3 micron layer of nickel-vanadium alloy (on the order of 7% vanadium). The preferred recording layer is a sputtered composite structure comprising a layer of chromium and an overlying layer of a cobalt-chromium alloy. Modulation effects can be substantially eliminated by heating the aluminum base prior to sputtering the nickel-vanadium undercoat, and by oxidizing the undercoat prior to deposition of the overlying layers.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.