| 摘要 |
PURPOSE:To carry out easily and effectively tracking of the light beam with respect to the recording track by providing the tracking track independently from the information signal recording track. CONSTITUTION:The information signal recording track 2 is formed on the upper surface of the substrate 3 of transparent disc and on the lower surface of the substrate 3, the tracking track is formed. The reproducing laser beam 7 and the tracking laser beam 8 are respectively focused on the tracks 2 and 4 through the rotatable following half mirror 5. Then, the beam focused on the track 4 is incident on the light receiver 13 and converted into the track position detecting signal. According to the detecting signal, the rotating angle of the mirror 5 is controlled, thereby the beams 7 and 8 forming the beam spots precisely on the tracks 2, 4 respectively. In this manner, by the satisfactory position detecting signal without noise, the precise tracking control can be easily carried out. |
