| 摘要 |
PROBLEM TO BE SOLVED: To use one disk when only the other disk is required for recording program information at a disk stack composed of two disks. SOLUTION: A double side optical reading type information recording disk stack 10 has a disk 20, in which program information is recorded in the manner of optical reading, and a disk 40 on which a visually recognizable mark including a general-purpose mark 60 not depending on the program information in the disk 20 is recorded. The visually recognizable mark can include a mark depending on the program information in the disk 20. It is preferable for the visually recognizable mark to be formed on the disk 40 through various methods such as pit picture, thermal printing method, laser engrave printing and labelling before two disks 20 and 40 are bonded. Otherwise, it is also possible to form general-purpose information on the disk 40 as the visually recognizable mark in the manner of optical reading. |
