Slip-off preventing tracking control apparatus

摘要

In an apparatus in which information is reproduced by projecting/receiving an optical beam to/from a recording carrier having a large number of information tracks, tracking control is performed so as to maintain a reproducing position on an information track by supplying a track deviation signal to an actuator. If this track deviation signal becomes asymmetric by an inclination, etc. of the recording carrier so that a shock is applied to the apparatus, jumping out of a track occurs, resulting in slip-off of the optical beam from the reproducing position. This slip-off can be prevented by detecting a position of a movable support member carrying a focusing lens for projecting and receiving the optical beam and feeding back the position signal to the tracking control system, or by extracting a low-frequency component of an output signal of a control circuit and feeding back the extracted signal to the tracking control system.