Optical recording and retrieving disc
US4547875A · kind A · utility
7Cited by
7References
3Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Oct 7, 1982 |
| Grant date | Oct 15, 1985 |
| Priority date | — |
| Expiry date | Oct 7, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/24
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
An optical disc for optical recording, retrieving and erasing of informations. The phase difference .psi. of reflected light produced by the tracking groove in the form of convexity or protrusion of concavity or groove and the change .DELTA..psi. in the phase difference caused by a recording in a recording film are selected in relation to each other to provide a stable detection signal for tracking, thereby to permit a highly accurate tracking on the optical disc carrying information at a high density.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.