| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical disk having a means for easily protecting data. <P>SOLUTION: An attachable and detachable sheet 1 is pasted on the side of a recording surface where a light beam 4b is made incident to an information layer 3 of the optical disk, and access to data is controlled by collating security information formed in the information layer 3 of the optical disk with information formed in the sheet 1 and visually confirmed by irradiation with a wavelength contained in the optical beam 4b. By the constitution, security protection of an information signal recorded in the information layer 3 of the optical disk can be heightened. <P>COPYRIGHT: (C)2008,JPO&INPIT |
