| 摘要 |
In an optical disc including a discoid optical-disc substrate and a coating film formed on the optical-disc substrate, the optical-disc substrate includes a first region including the innermost periphery thereof and having a projection formed on the whole of the first region, and a second region located outside of the first region. The coating layer is formed on the second region. Before the coating film is formed, the thickness of the optical-disc substrate at the first region is greater than the thickness of the optical-disc substrate at the second region. After the coating film is formed, the total thickness of the optical-disc substrate at the second region and the coating film is greater than the thickness of the optical-disc substrate at the first region. |
