Optical information recording medium having protection layers with different properties on both sides of an optical active layer
US5453346A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 29, 1994 |
| Grant date | Sep 26, 1995 |
| Priority date | — |
| Expiry date | Mar 29, 2014 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/146
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
In a phase change optical disk wherein a first heat-resistant protection layer, an optical active layer showing a reversible phase change between a crystal state and an amorphous state, and a second heat-resistant protection layer are laminated on a substrate in this order, both of the first and the second heat-resistant protection layers are made of a mixture of a chalcogenide and a vitrification accelerating material. Further, a mixture ratio of the vitrification accelerating material in the second heat-resistant protection layer is larger than that in the first heat-resistant protection layer. Thereby, it becomes possible that the first heat-resistant protection layer has the mixing ratio which gives the refractive index value bringing suitable optical properties, while the second heat-resistant protection layer has the different mixing ratio which gives the thermal conductivity bringing suitable thermal properties. As a result, a phase change optical disk having high sensitivity, improved life characteristics in repeated record/erasure operations and wide production margin is provided.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.