Optical recording medium
US5688574A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 14, 1996 |
| Grant date | Nov 18, 1997 |
| Priority date | — |
| Expiry date | Mar 14, 2016 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31678
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Disclosed is a phase-change optical recording medium which has a reflectance and a signal modulation conformed to the CD standard, and which is usable for recording at the same linear velocity as the reproducing velocity specified in the CD standard. The phase-change optical recording medium comprises a metallic layer, a first protective layer, a recording layer, a second protective layer, and a reflecting layer on a substrate, in which recording is performed through change from a crystalline state to an amorphous state in the recording layer. The recording layer comprises a recording material of a Ge--Te--Sb--Se system, and the recording layer has an average composition in a direction of thickness which satisfies the following relations as represented by atomic %: EQU Ge.gtoreq.40%, and Sb+Se.ltoreq.25% The recording medium has a reflectance of not less than 70% with respect to a light beam for reproduction when the recording layer is in one of the crystalline state and the amorphous state, and the recording medium has a reflectance of less than 40% when the recording layer is in the other state. An AuCo alloy is used as the metallic layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.