| 摘要 |
PURPOSE:To detect the center point of recording tracks, by irradiating more than one point on the innermost circumference of a disk recording surface with single-wavelength light beams and detecting their reflected light beams. CONSTITUTION:A disk mounting table 1 on which a recording disk 2 is mounted is movable in directions X and Y independently by carriage motors 3 and 4. The circumference of an innermost circumferential track is irradiated with single-wavelength laser beam bundles (a)-(d) from four unshown light sources, and their reflected light beams are made incident to photodetectors 6-9. Then, the carriage motors 3 and 4 are driven in accordance with a difference in the quantity of the reflected light and when the track center point of the disk is found, a center hole is bored by a working drill. |
