Device for optically scanning a recording medium by focusing the best focus or the paraxial focus to the information layer
US5708638A · kind A · utility
45Cited by
3References
21Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Mar 14, 1996 |
| Grant date | Jan 13, 1998 |
| Priority date | — |
| Expiry date | Mar 14, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B2220/90
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical scanning device can scan two types of record carriers each having a transparent layer with a different thickness, in which a radiation beam scans an information layer of the record carrier through the transparent layer. When scanning a first type of record carrier the best focus of a scanning radiation beam is positioned on the information layer and when scanning a second type of record carrier the paraxial focus of the radiation beam is positioned on the information layer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.