| 摘要 |
PURPOSE: To indicate a pattern of large character, for example, clearly by employing a double-sided optical disc having an information record disc part and a dummy disc part. CONSTITUTION: The optical disc 42 is a double sided disc where an information record disc part 12 and a dummy disc part 11 are bonded through an adhesive layer 5. The information record disc part 12 comprises a substrate 8 having one side provided with a row of information pits 10 for forming a concentric or spiral recording track, a reflection layer 7 and a protective layer 6. The dummy disc part 11 comprises a substrate 2 having one side provided with a group of dummy pits 9 having no relation to the information signal, a reflection layer 2 provided on the pit forming face of the substrate 2, and a protective layer 4. Contrary to the conventional art, a visible pattern is formed by a group of dummy pits formed on the other recording face different from the information recording face, and a pattern of large character can be indicated clearly, for example. |
