| 摘要 |
PROBLEM TO BE SOLVED: To make illegal recording/reproducing of information data impossible by providing groove tracks with plural groove parts cut into pieces in the rotating direction of an optical recording medium by groove non-forming parts and including one of the groove non-forming parts in each of mark parts or each of space parts. SOLUTION: Groove tracks 12 are formed as the part of the same depth (the same plane) as land tracks 13, i.e., intermittent groove tracks divided by a groove non-forming part excepting the vicinity of the re-pit column consisting of three pre-pits 14A, 14B, 14C. The length of individual groove parts and groove non-forming parts (mirror part) is equivalent to the length of a pit and the interval of the pit formed by information recording, and each of the groove parts corresponds to the mark (or space) of information data. Thus, the level of the reproducing RF signal of a control data part becomes low at the time of reproducing, and consequently reproducing of control data becomes impossible. |
