| 摘要 |
PURPOSE:To eliminate useless power consumption and to reproduce both of a normal disk and an SR disk. CONSTITUTION:An information signal is reproduced from both of an optical disk (normal disk) forming a reflection layer on a transparent substrate forming a phase pit and the optical disk (SR disk) forming material layer changing reflectance in accordance with temperature on the transparent substrate forming the phase pit. The linear recording density of the SR disk is defined as (m) times of the same of the normal disk. By the sub code of read-in of the optical disk 31, the kind of the disk is discriminated. When the disk is normal one, the power of a laser beam source 32 is reduced, further, the disk is reproduced by the disk rotation of a high linear velocity. Thus, the useless power consumption is prevented. When the disk is SR one, the power of the laser beam source 32 is increased, further, the disk is reproduced by the disk rotation of a low linear velocity (1/m times of normal disk). In such a case, the disk is reproduced at the same transfer rate as the same of the normal disk at the time of reproducing, further, an ultra-high resolution reproduction in company with the partial solution of the material layer is performed. |
