| 摘要 |
PURPOSE:To decrease the fault rate of an optical disk storage device by using a laser beam source for recording as an alternative laser beam source for eras ing in the case of fault such as disabling or lowering the output of a laser beam source for erasing. CONSTITUTION:When a laser beam source 1E for erasing breaks down, a control ler 15 detects the quality abnormality of a reproducing signal and a fault detec tion circuit 14 detects the fault of the beam source 1E. With this detection, the circuit 14 outputs a fault laser designation signal ORS to a switching circuit 12 and simultaneously outputs a fault detection signal ODS to the controller 15. According to the signal ORS, the circuit 12 cancels connection between a laser driving circuit 11E for erasing and the controller 15 and regards the driving instruction of the beam source 1E as the driving instruction of a beam source 1W. On the other hand, an operation sequence is changed by the input of the signal ODS in the controller 15, and a switch control signal CTL is transmitted to the circuit 12. Thus, the fault rate of the optical disk storage device is reduced. |
