METAL MOLD DEVICE FOR MANUFACTURING DISK-LIKE SUBSTRATE MATERIAL, METHOD OF MANUFACTURING DISK-LIKE SUBSTRATE MATERIAL, DISK-LIKE SUBSTRATE MATERIAL FOR OPTICAL DISK, AND OPTICAL DISK

摘要

A metal mold device (30) capable of forming a disk-like substrate material for an optical disk with a center hole so that a resin layer with uniform thickness distribution can be formed thereon, a stamper (10) is held on a movable metal mold (34) by a sucking means (36) in a cavity (31), a through-hole (10A) smaller in diameter than the center hole of the optical disk is formed in the stamper (10), and a metal mold split line and a step are not present at the portion of the information recording surface (12A) of the disk-like substrate material (12) formed by injection molding corresponding to an area ranging from the outer periphery of the stamper (10) to the through-hole (10A).