| 摘要 |
PROBLEM TO BE SOLVED: To perform stable tracking servo by arranging a coloring light beam spot between the tracking servo beam spot of a front side and a reproducing light beam spot. SOLUTION: A reproducing light beam spot 4 is scanned on a track in the direction of an arrow A and tracking servo beam spots 2 and 3 are disposed in the front and rear sides of this spot 1. In this condition, spots 1 to 4 are scanned in the direction of the arrow A. Since the coloring light beam spot 4 is arranged between the beam spot 2 of the front side and the beam spot 1, the colored area 7 of a mask layer colored by the beam spot 4 is formed in the rear side of the spot 2. Thus, non-colored areas exit in a position for irradiating the spot 2 with a light. Since the beam spot 3 is positioned in the rear side of the beam spot 1, an area discolored by the beam spot 1 is irradiated. |
