Magnetooptical information recording and/or reproducing method and apparatus in which prior to actual recording and/or reproducing, information is recorded on a recording medium to set reference conditions for actual recording and/or reproducing
US5581524A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Mar 25, 1993 |
| Grant date | Dec 3, 1996 |
| Priority date | — |
| Expiry date | Mar 25, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B11/10573
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Recording of information on and/or reproduction of information from a magnetooptical recording medium is effected as follows. A light beam from an objective lens is irradiated on a track of the recording medium. The objective lens is driven in a direction perpendicular to the track such that the beam spot and the track have a predetermined positional relationship therebetween. A magnetic field modulated according to information to be recorded is applied to the beam spot irradiated position of the recording medium by a magnetic field applying device. A relative position between the objective lens and the magnetic field applying device in the direction perpendicular to the track is detected. The recording of information is effected on the recording medium by applying the magnetic field according to the information while changing the beam spot irradiated position on the recording medium with respect to the track. The movable range of the objective lens, in which a level of a reproduction signal obtained in the reproduction of information exceeds a predetermined level, in the direction perpendicular to the track, in the recording operation, is detected on the basis of a detection resul…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.