TRACKING CONTROL DEVICE, TRACKING CONTROL METHOD, AND OPTICAL DISC APPARATUS

摘要

A tracking control device includes a signal detector that detects a tracking error signal, and a crossing direction, a crossing period and a crossing velocity of an objective lens from a detection signal of an optical detector, a tracking drive signal generator that generates a tracking drive signal on the basis of the tracking error signal, a velocity-reduction drive signal generator that generates a velocity reduction drive signal for converging the crossing velocity into a vicinity of zero on the basis of the crossing direction and the crossing period, a loop switch, and a system controller that causes to executes velocity reduction driving for driving the objective lens actuator on the basis of the velocity reduction drive signal and that controls each of the members so as to switch from the velocity reduction driving to driving for driving the objective lens actuator on the basis of the tracking drive signal.

主权项

1. A tracking control device comprising:
a signal detector to detect, from a detection signal of an optical detector that receives light reflected from a track of a rotating optical disc, a tracking error signal, and a crossing direction, a crossing period and a crossing velocity of an objective lens with respect to the track; a first drive signal generator to generate, on a basis of the tracking error signal detected by the signal detector, a first tracking drive signal for driving an objective lens actuator that moves the objective lens of an optical pickup in a tracking direction; a second drive signal generator to generate, on a basis of the crossing direction and the crossing period detected by the signal detector, a second tracking drive signal for converging the crossing velocity into a vicinity of zero; a drive signal switch to switch a drive signal supplied to the objective lens actuator; and a system controller to control operation of the first drive signal generator, the second drive signal generator and the drive signal switch so as to cause to execute second driving for driving the objective lens actuator on a basis of the second tracking drive signal and switch from the second driving to first driving for driving the objective lens actuator on a basis of the first tracking drive signal, thereby causing to execute the first driving; wherein: the signal detector includes an optical-disc eccentric angle detector to detect an optical-disc eccentric angle of the rotating optical disc, and the system controller causes to start the second driving of the objective lens actuator based on the second tracking drive signal at a timing when the optical-disc eccentric angle is substantially 0 degrees or 180 degrees.