DISK WITH HUB AND INJECTION MOLD FOR DISK SUBSTRATE

摘要

PURPOSE:To facilitate the registration of a hub and an information region and to prevent the flawing of the information region by providing the disk substrate on the periphery of a central hole with a recessed part and fixing a hub therein via a level difference provided therebetween. CONSTITUTION:The recessed part 2 is formed near the central hole of the disk substrate 1 and the hub 3 for transmitting rotating force via the recessed part 2 is fixed therein with the level difference provided slightly higher than the information region 1c. The hub 3 and the region are thus easily and exactly aligned. A cartridge is brought into contact first with the hub 3 by this level difference and the damaging of the region 1c by the contact with the cartridge is prevented. Further, the reduction in the thickness of the constitution, the improvement in the rigidity, etc., are attained.