Optical information recording/reproducing method and apparatus for performing auto-tracking control using a three-beam method, with respect to first and second recording media having different track pitches
US5917790A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 6, 1997 |
| Grant date | Jun 29, 1999 |
| Priority date | — |
| Expiry date | Jun 6, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG11B7/0903
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
Different tracks on an optical information recording medium are irradiated with first and second light spots for auto-tracking. The light of the first light spot via the recording medium is detected to produce a first detection signal and light of the second light spot via the recording medium is also detected to produce a second detection signal. On the basis of a difference between the first and second detection signals, a signal used for performing tracking control of a third light spot for recording or reproducing information is generated. When recording or reproduction of information is effected on/from one of a first recording medium having a track pitch P.sub.1 and a second recording medium having a track pitch P.sub.2 and the first and second recording media satisfy a relation P.sub.1 -P.sub.2 =d (d is the width of the tracking track) while executing auto-tracking control, a relationship of a direction of movement of the third light spot in a track intersecting direction with respect to a polarity of a signal obtained by subtracting the second detection signal from the first detection signal between the first and second recording media is inverted.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.