OPTICAL DISK, AN OPTICAL DISK BARCODE FORMING METHOD, AN OPTICAL DISK REPRODUCTION APPARATUS, A MARKING FORMING APPARATUS, A METHOD OF FORMING A LASER MARKING ON AN OPTICAL DISK, AND A METHOD OF MANUFACTURING AN OPTICAL DISK

摘要

A barcode is formed on an optical disk. The optical disk is provided with a control data area and an identifier for indicating the presence or absence of the barcode in the control data area. A beam pattern if focused on a reflective film of the optical disk in an information signal region on which the data is recorded. Information is provided for making the barcode. The information is PE-modulated so that a width of a mark of the barcode is half or less than a period of the barcode marks. The optical disk is rotated to form the barcode.