| 摘要 |
PURPOSE:To prevent significant information from being dissipated by providing a laser output control means which controls the output of a laser based on the output of a first light detecting means, a second light detecting means which monitors the strength of a laser beam, and a stopping means for the laser output control means based on the output of the detecting means. CONSTITUTION:Recording/reproduction is performed by irradiating an information carrier 5 with the laser beam emitted from the laser 1 by an optical head. Also, the strength of the laser beam is monitored by the first light detecting means 8, and the output of the laser 1 is controlled based on the output of the first light detecting means 8. Furthermore, the strength of the laser beam is monitored by the second light detecting means 10, and it is compared with a reference power source 11 by a comparator 12, and the output of the laser output control means 9 is stopped by a switch 13 based on the output of the second light detecting means 10. Thereby, it is possible to stop the radiation of the laser beam before information on the disk 5 is impaired due to the occurrence of abnormality in reproduction and the increment of the output of the laser beam. |
