| 摘要 |
PROBLEM TO BE SOLVED: To perform a correct failure prediction concerning the life of a semiconductor laser by calculating a laser life time based on the optimum power obtained in a trial write processing and issuing a warning when the life time exceeds a threshold value. SOLUTION: A cumulative time when an effective power equivalent to a read power is emitted is calculated by reading data (1) of a laser-ON time with a warning judging block 15 in a memory block. Also, a cumulative time when an effective power equivalent to a recording power is emitted is calculated by reading data (2) of the number of write blocks similarly and a cumulative time when an effective power equivalent to an erasing power is emitted is calculated by reading data (3) of the number of erasure blocks similarly. Then, light emitting cumulative times corresponding to the data (2), (3) are weighted with coefficients in oreder to be converted into a lifetime to become an effective time and the effective time is stored to be summed up with an effective time when the normal reproducing power of a reproducing time and a seek time or the like and the summed effective times are compared with the threshold value set for judging a warning. |
