HUB TYPE OPTICAL DISK AND INJECTION MOLDING DIE FOR MOLDING ITS DISK SUBSTRATE

摘要

A hub type optical disk (K1) comprising: a disk substrate (1) which has a center hole (1a), a clamp area (1b) disposed radially outwardly of the center hole (1a) and a data area (1c) disposed radially outwardly of the clamp area (1b); wherein a recess (2) is formed at an inner peripheral portion of one face of the disk substrate (1), which includes the clamp area (1b), while a projection (1A) is formed in the clamp area (1b) on the other face of the disk substrate (1) such that thickness of the disk substrate (1) is substantially uniform at the clamp area (1b) and the data area (1c); and a hub (3) which is engageable with a disk mounting member (105a) of an optical disk apparatus and is secured in the recess (2).