OPTICAL DISK, BAR CODE FORMATION METHOD FOR OPTICAL DISK, OPTICAL DISK REPRODUCTION APPARATUS, AND MARKING METHOD, LASER MARKING METHOD FOR OPTICAL DISK, AND METHOD OF OPTICAL DISK PRODUCTION.

摘要

A bar code formation method for an optical disk, which produces bar codes of position information for piracy protection as a kind of ID and executes laser trimming to a reflection film of a PCA region of an optical disk. An optical disk is produced according to this method. As shown in the Figure, a reflection film of a PCA region (998) is partially removed in the PCA region (998) of a pre-pit signal region of this optical disk to which data are recorded by CLV so that bar codes (923) and (938) are written in superposition. In this optical disk, therefore, bar code data can be reproduced by the same optical pickup.