Patent ID: 7229679

Claim:
An optical disk comprising: a first substrate including a first surface on which a first record layer, a first non-recording region and a first ring-shaped projection are formed, the first non-recording region formed radially inward of the first record layer, and the first ring-shaped projection formed inside the first non-recording region; a second substrate including a second surface, which is different from the first surface, and on which a second record layer, a second non-recording region and a second ring-shaped projection are formed, the second non-recording region formed radially inward of the second record layer, and the second ring-shaped projection formed inside the second non-recording region; and a light-transmissive spacer layer, wherein the first and the second record layers are opposed to each other, the first and second ring-shaped projections are opposed to each other, and the light-transmissive spacer layer is filled in a gap between the first and second ring-shaped projections and in a gap between the first and second record layers.