| 摘要 |
PROBLEM TO BE SOLVED: To realize reductions in power consumption and a data error rate by discriminating kinds of a plurality of recording mediums, selecting a laser light source having a corresponding wavelength and adjusting a laser oscillating voltage of the light source in accordance with the wavelength. SOLUTION: Kinds of optical disks 407 are discriminated by differences in a starting point of a data region. At this time, a semiconductor laser 101 having a wavelength of 635 nm is used. An oscillation switch 119a is turned on so that at power supply 115 is connected to the semiconductor laser 101. An optical head including a reflection system 103, multi-foci hologram optics 104, a half mirror 105, and a sensor 106 is moved to a starting point of a recording region of the optical disk 407. A signal detecting circuit 110 detects a reproduced signal from an output of the sensor 106. A binary data of an output of a binarizing circuit 111 is processed by a data detecting circuit 112 to detect a reproduced data. At this time, when the data can be normally reproduced by the data detecting circuit 112, a wavelength selection circuit 113 judges that the optical disk is a DVD and outputs a discrimination signal 107 to a power supply control circuit 108 to select either the semiconductor laser 101 or a semiconductor laser 102. |
