| 摘要 |
PURPOSE:To facilitate tracking servo at the time of writing by confining the total thickness of a light absorption layer and other layer formed between the front surface of a light-transmissive substrate formed with guide grooves and a light reflection layer to a specific value or below. CONSTITUTION:The light absorption layer 2, the light reflection layer 3 and a protective layer 4 are successively laminated on the light transmissive substrate 1 formed with the guide grooves 1a for tracking servo on the front surface. The total of the thicknesses of the light absorption layer 2 formed between the front surface of the substrate 1 and the light reflection layer 3 and the other layer is confined to <=2mum. Since pits and the guide grooves 1a are included in the focal depth in this way, the focus servo and tracking servo are facilitated. |
