Method of manufacturing an optical recording/reproducing disc
US4546464A · kind A · utility
14Cited by
7References
4Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 4, 1983 |
| Grant date | Oct 8, 1985 |
| Priority date | — |
| Expiry date | Oct 4, 2003 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/24097
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical recording/reproducing disc is formed of round plastic plates between which is a recording layer capable of optically recording and reproducing signals, and a round protective layer of plastic material provided on the recording layer and having at the outer peripheral end a projection higher by 10 to 200.mu. than the inner peripheral surface of an effective recording/reproducing surface. Thus, when the disc is placed on a flat plane, a space is formed between the flat plane and the recording layer due to the projection, thereby preventing flaws from being produced by contact with dust or a foreign object.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.