| 摘要 |
PURPOSE:To form a visual pattern, of which regular shape is lost when it is copied, on a CD-ROM. CONSTITUTION:An area for forming a character/graphic pattern is provided on a CD-ROM 4. The character/graphic pattern 14 is formed by recording data for generating two kinds of pit patterns making a visual difference between them in average reflectance on the CD-ROM 4 in the internal part and the external part of the textural/graphic pattern respectively. By this method, unless a copy version CD-ROM is produced by copying the original version CD-ROM with extremely high accuracy, the character/graphic pattern is out of shape by deviating the disposition of the pit patterns from the original version, thus, its vidual recognition is impossible. |
