Optical recording medium
US4740447A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 2, 1985 |
| Grant date | Apr 26, 1988 |
| Priority date | — |
| Expiry date | Dec 2, 2005 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/146
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical recording medium such as an optical disc memory, with which data can be stored and reproduced by means of laser beam with a high sensibility is disclosed. The optical recording medium comprises: PA1 a substrate transparent to the laser beam; PA1 a first spacer layer formed on the substrate, being substantially transparent to the laser beam and having a higher refractive index than the substrate with respect to said laser beam; PA1 a second spacer layer formed on the first spacer layer, being substantially transparent to the laser beam and having a lower refractive index than the first layer with respect to said laser beam; and PA1 a recording layer formed on the second spacer layer and for storing data therein by the radiation of laser beam. The thickness of the first spacer layer is not larger than a thickness at which the first spacer layer, when combined only with the substrate, presents a maximal reflectivity with respect to a laser beam being incident on the substrate and the thickness of the second spacer layer is smaller than a thickness at which the second spacer layer, when combined only with said first spacer layer and the substrate, presents a minimal reflecti…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.