Record playback apparatus and information record therefor
US4189735A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 24, 1978 |
| Grant date | Feb 19, 1980 |
| Priority date | — |
| Expiry date | Feb 24, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/165
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Playback apparatus, providing a playback beam of light, effects signal recovery, from an information record, with a high signal-to-noise ratio. An information record, suitable for use with such playback apparatus, comprises a flat major surface of a disc-shaped foundation coated with a layer of a thermally conductive material overlaid with a layer of a thermally insulating material. Information storage is effected in a layer of material (e.g., platinum-cobalt), highly absorptive for light of a frequency supplied by a recording laser, which layer overlies the insulating layer. By proper choice of thicknesses for the insulating and the conductive layers, absorptive layer sensitivity to the intensity of the playback beam of lights is effectively reduced to enable record playback at high playback beam intensity levels without damage thereto. Where the foundation is formed of a thermally conductive material, the layer of thermally conductive material may be dispensed with.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.