METHOD FOR MACHINING OPTICAL DISK STAMPER, METHOD FOR MANUFACTURING PTICAL DISK STAMPER, OPTICAL DISK STAMPER, METHOD FOR MANUFACTURING OPTICAL DISK SUBSTRATE, OPTICAL DISK SUBSTRATE, AND APPARATUS FOR MACHINING OPTICAL DISK STAMPER

摘要

A method for machining an optical disk stamper, by which a groove, a pre-pit group in a groove track and a pre-pit group in a land track are made with a high quality and a good balance by a laser. A beam deflector is mounted in the optical path of a laser optical system of the laser for making the pre-pit group and is so adjusted that the laser beam for making the prepit group is applied substantially to the center of the group track and the land track. Moreover, the laser beam is deflected with an equal deflection in opposite directions by the beam deflector thereby to make the two pre-pit groups. The difference in the diffraction efficiency due to the difference in the deflection directions is corrected by the independent control of the laser power.