| 摘要 |
PURPOSE:To perform injection molding of a plastic board for an optical disk whose retardation is low and signal transfer properties are favorable under stabilized molding terms, by a method wherein the height of a crest over submicron in a signal stamper becomes higher at a linear slope extending to the external circumference from the internal circumference. CONSTITUTION:When injection molding is performed by making use of a signal stamper whose height of a signal crest of the internal circumference (at a position of the radius of 25mm) is 0.03-0.30mum, moreover, whose height of the signal crest becomes higher at a linear slope extending to the external circumference from the internal circumference and whose slope falls within a range of 7X10<-5>-5X10<-9>, then a plastic board for an optical board whose retardation and signal transfer properties are favorable can be manufactured. In addition to the above, when the optical disk is manufactured by making use of a disk board obtained by performing injection molding by making use of the signal stamper and characteristics of the optical disk is evaluated by applying driving to the optical disk, the disk which possesses an error rate of less than 1X10<-6> and is very good is obtained. |
