Record carrier with an optically readable radiation-reflecting information structure
US4230915A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 26, 1978 |
| Grant date | Oct 28, 1980 |
| Priority date | — |
| Expiry date | Dec 26, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/24076
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A record carrier is described having an optically readable radiation-reflecting information structure, which comprises trackwise arranged information areas which, in the track direction and transverse to the track direction, are spaced from each other by intermediate areas. It is demonstrated that if the angle of inclination between the walls of the first areas and the normal to the record carrier has one value between 30.degree. and 65.degree. for a satisfactorily reproducible record carrier, the geometrical distance between the plane of the information areas and the plane of the intermediate areas should have one value between (165/N) nanometers and (270/N) nanometers, N being the refractive index of a transparent medium which is disposed between the first and the second plane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.