PURPOSE: To secure the high-accuracy tracking control by detecting the reflected light from the recording medium through the optical detector containing the divided regions and then controlling the light beam driving unit with the differential output.
CONSTITUTION: Light beam 5 given from light source 4 is focused on recording disk 1 which functions as the recording medium via lens 6, optical element 7 and condenser lens 8 each. And the reflected light given from disk 1 is separated by element 7 to be supplied to 2-division optical detector 10, and the output of each divided region of detector 10 is supplied to differential amplifier 11. This differential output drives driving element 13 attached to movable part 14 including light source 4 and lens 6. As a result, the high-accuracy control is ensured so that the light beam focused on disk 1 may always be on the track.
DEGUCHI MASAHIRO
WAKAMI NOBORU
GOTOU YASUHIRO
| JPS5198002A | 1976-08-28 |