OPTICAL DISK DEVICE SETTABLE TO OPTIMUM POWER

摘要

PURPOSE:To securely and unequivocally set lowermost power by detecting peak power and the lower limit power of bias power and then detecting optimum power for an optical disk device. CONSTITUTION:A drive control circuit 9 gives the instruction of the retrieval of an evaluation track to a retrieval circuit 5 by the instruction from a start circuit 19. A reproduction signal from the evaluation track is guided to an unrecorded part detector 4 and a demodulator 3 through an amplifier 2 from a photodetector 1. A reproduced signal propriety judgement circuit 6 judges a recording signal recorded by optimum peak power and optimum bias power. Either peak power or bias power is fixed and it is gradually (dX and dY) reduced from the other high power-side so as to detect minimum lower limit power by which the recording signal is accepted by the reproduced signal propriety judgement circuit 6. Thus, optimum peak power can be detected even if peak power fluctuates in a real use state in spite of the type of a recording medium.