Signal to noise ratio of a multiple layer optical disk with modulated beam
US5258969A · kind A · utility
15Cited by
13References
6Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 28, 1992 |
| Grant date | Nov 2, 1993 |
| Priority date | — |
| Expiry date | Apr 28, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/14
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
The invention relates to the reading of optical disks in which the recording is performed in volume in separate layers. Reading a bit recorded within the layers gives a signal with a background noise from all the adjacent bits illuminated by the read beam. In order to eliminate this background noise, the read beam is modulated in position about the bit to be read, either horizontally or vertically with respect to a recording level. The background noise remains unchanged but the signal from the bit being read becomes a periodic signal.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.