MOLD FOR MOLDING OPTICAL DISK, MOLDED SUBSTRATE AND OPTICAL DISK

摘要

PROBLEM TO BE SOLVED: To prevent the generation of a burr in an optical disk substrate. SOLUTION: An outer peripheral ring 22 forming the outer peripheral part of a cavity 31 is divided in its peripheral direction to be formed of an outer peripheral ring member 25 and an inner peripheral ring member 26. The inner peripheral ring member 26 is formed from bearing balls 27 and a holding member 28 for holding the bearing balls 27.