Tracking servocontrol circuits for reducing gain to avoid tracking defect in an optical reproducing apparatus

Claim 1

A tracking servocontrol circuit for use in an optical reproducing apparatus; comprising: signal generating means for producing a tracking error signal representing a tracking error in respect of a light beam scanning a record track on a recorded surface of a record medium from which a reproduced information signal is obtained; driving means operative to move the position of the light beam on the record medium for tracking servocontrol; a servocontrol amplifier formed with a gain control terminal and supplied with the tracking error signal for producing a drive signal in response to the tracking error signal and supplying said drive signal to said driving means; defect detecting means for detecting a variation in the reproduced information signal resulting from a defect on the recorded surface of the record medium and producing a detection output signal corresponding thereto; and control means operative in response to a predetermined detection output signal of said defect detecting means to supply said detection output signal to said gain control terminal to reduce the gain of said servocontrol amplifier and thereby prevent the drive signal supplied to said driving means from being harmfully affected by the defect on the recorded surface of the record medium.