Method of recording and erasing information in an erasible optical recording medium
US5230973A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 24, 1990 |
| Grant date | Jul 27, 1993 |
| Priority date | — |
| Expiry date | Aug 24, 2010 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/146
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical information recording medium is disclosed in which the recording layer is a material capable of absorbing energy and being reversibly converted between a substantially non-crystalline or amorphous state and a substantially crystalline state. The recording layer is a Te-Ge-Sb composition which also contains nitrogen. The optical recording medium includes a substrate onto which is sequentially deposited a first dielectric layer, a nitrogen-containing recording layer, a second dielectric layer and a metallic reflecting layer. In order to control the sensitivity of the medium to laser irradiation, the second dielectric layer is graded in thickness and progressively becomes thicker as a function of increasing radius. Alternatively, in another embodiment, the reflecting layer is graded in thickness, and progressively becomes thinner as a function of increasing radius. To further optimize the write/erase characteristics, the write to erase power ratio, as well as the recording duty cycle of the laser are varied as a function of radial position.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.