Processing and manufacturing method of a master for optical disk, the master for optical disk, a manufacturing method of an optical disk substrate, the optical disk substrate, and a processing device of a master for optical disk

Abstract

A processing method of a master for optical disk by a laser processing to form grooves, prepit groups on a groove track and prepit groups on a land track in a high quality and in a good balance. On an optical course of a laser beam for forming the prepit groups, an optical deflector is provided. Also, the laser beam is positioned to shoot on the center of the groove track and the land track. The deflector deflects the laser beam in the same amount of deflection to the opposite direction to form each of the prepit groups. Further, a difference in diffraction efficiencies by a difference in the deflection directions is corrected by controlling the laser power independently from each other.