| 摘要 |
PROBLEM TO BE SOLVED: To enable information signals to be recorded on the recording face of an optical recording medium using a hologram hard to be forged. SOLUTION: In this method, a hologram showing an additional information signal is recorded in the two-dimensional area a, b:101 on the face of an optical recording medium 100 having a spiral or concentric track, and the contents information is encoded in variable length and recorded in the areas A, B, C other than the two-dimensional area so that it becomes a user data area. |
