Tracking device to effect tracking pull-in in an optical recording and reproducing apparatus by vibrating a light spot

摘要

A tracking device usable in an optical information recording and reproducing apparatus for an optical information record medium on which a plurality of tracks are arranged substantially parallel in a first direction. The device includes a light source, a first optical system for forming a small spot on the record medium by converging a light beam from the light source, a second optical system for obtaining the light beam from the record medium, a detecting device for receiving the light beam obtained by the second optical system to output a tracking signal, a vibrating device for vibrating the spot relative to the record medium in a second direction intersecting the first direction, a control device for effecting tracking control with respect to a track, and a selecting device for selectively actuating the vibrating device and the control device in accordance with the tracking signal from the detecting device.