Thick protective overcoat layer for optical video disc
US4315269A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 29, 1977 |
| Grant date | Feb 9, 1982 |
| Priority date | — |
| Expiry date | Aug 29, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/2595
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical recording medium comprises a light reflecting material which is coated with a light absorbing layer and overcoated with a 0.05-1 millimeter thick layer of an optically transparent and chemically and thermally stable material such as a silicone resin. During recording, portions of the light absorbing layer are ablated or melted by a modulated focussed light beam, thereby exposing portions of the reflecting layer while leaving the overcoat layer intact. Information is recorded in the form of a reflective-antireflective pattern. Dust particles and other surface contaminants settle on the upper surface of the overcoat layer, so far removed from the focal plane of the recording lens that their effect on the recording or playback signal is considerably reduced, and no defect is noticeable on the playback monitor.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.