| 摘要 |
PURPOSE:To permit an optical beam to pass within the effective image circle of an objective lens without fail during tracking drive by providing a reflecting body which is displaced in one body through the operation of a tracking driving means in an oscillator and collimating the optical beam between the objective lens and an optical device. CONSTITUTION:When a disk turns with surface undulation, the lens holding part 9a of the oscillator is displayed upward and downward in parallel through the operation of a moving coil 15 for focusing according to the surface undulation to condense the beam to the recording surface of the disk 1. When the disk 1 turns with only eccentricity, the mirror holding part 9b and lens holding part 9a are driven through the operation of a moving coil 17 for tracking and the objective lens 11 is displaced left and right in parallel according to the eccentricity, thereby finely displacing the beam in a radius direction so that it scans on the track of the recording surface of the disk 1. |
