Tracking control system with correction capabilities for correcting disagreement between optical axes

摘要

A tracking control system according to the present invention includes an objective lens for converging a light beam at a point on a recording medium to form a converging spot; a galvano-mirror for receiving a driving signal and for moving the converging spot across tracks provided on the recording medium in response to the driving signal; a tracking error detecting section for generating a tracking error signal according to a position of the converging spot with respect to one of the tracks; a tracking servo control section for generating a first driving signal according to the tracking error signal end for feeding the first driving signal to the galvano-mirror as the driving signal, by which the galvano-mirror is driven so that the converging spot is located on the one track; a signal selection circuit for turning on and off the tracking servo control section; a driving section for, when tracking servo control is turned off, generating a second driving signal by which the galvano-mirror is driven so that the converging spot crosses predetermined number of tracks among the tracks; a measuring section for, when the tracking servo control is turned off, measuring a degree of disagreement of optical axes based on the tracking error signal obtained by driving the galvano-mirror with the second driving signal; and a correcting section for correcting the disagreement of optical axes by constantly supplying the galvano-mirror with a current for making the degree of disagreement of optical axes substantially zero based on the measured degree of disagreement of optical axes.