| 摘要 |
<p>An optical information recording and reproducing apparatus for an optical information record medium (101) on which a plurality of tracks are arranged substantially in parallel, comprises a light source (107), a first optical system (108,119,109) for forming a small spot on the record medium by converging a light beam from the light source, a second optical system (109,113) for obtaining the light beam from the record medium, a detecting device (115,10,11,12) for receiving the light beam obtained by the second optical system to output a tracking signal, a vibrating device (15,111) for vibrating the spot relatively to the record medium in a direction intersecting the extension of the track, a control device (13,111) for effecting a tracking control with respect to the track, and a selecting device (17,16,14) for selectively actuating the vibrating device and the control device in accordance with the tracking signal from said detecting device.</p> |
