| 摘要 |
PROBLEM TO BE SOLVED: To prevent illegal copying without decreasing the recording capacity of a recording medium.SOLUTION: On a recording surface 10A of a recording medium 10, spiral groove portions 120 on which recording pits 128 having predetermined length as digital data are formed and aligned by laser radiation; and a spiral land portion 122 provided between the adjacent groove portions 120, and having land prepits 126 provided at predetermined intervals so as to specify positions on the recording surface 10A of the recording pits 128 are provided. On the land portions 122, dummy pits 130 of the land prepits 126 are provided. By making it impossible to specify the positions of the recording pits 128 at copying, illegal copying is prevented. |
