| 摘要 |
PURPOSE:To perform detection of tracking error signals and others stably by setting the turning center of a hollow turning arm in such a way as to decrease the rates of inclinations of the objecting lens at the leading end of said arm in the directions tangential to the respective tracks on the loci of said lens owing to turning of said arm. CONSTITUTION:If the turning center of a hollow turning arm is installed in the position of roughly (l<2>+rminrmax)<1/2> with respect to the turning center of a discoidal recording medium where the distance between the turning center of the hollow turning arm and an objective lens is defined as (l), and the radii between the turning center of said medium and the information tracks on the innermost and outermost circumferences on the recording medium are defined as rmin, rmax, respectively, the angles of inclination of the tracks on the loci of the objective lens decrease and the detection of tracking error signals and the monitoring of recording information are accomplished always stably. |
