| 摘要 |
PURPOSE:To set recording light power accurately at an optimal level by detecting temperature distribution at a light beam irradiating part of a magneto- optical recording medium indirectly and then setting a recording light power based on detection result. CONSTITUTION:Predetermined recording test area on a magneto-optical disc 1 is brought into erased state and an LD driver 18 is commanded to record a pit row in predetermined pattern with recording laser power. The recording light beam is reflected on a magnetic layer 3 and introduced to a reproducing optical system where it is detected through photosensors 13a, 13b. Thus detected signals are then subjected to differential detection through a differential amplifier 14 and reproduced as a magneto-optical signal while optical bits recorded for the purpose of test are reproduced simultaneously with recording. Thus obtained magneto-optical signal is then fed to a signal processing circuit 15 where the amplitude of signal is detected. A controller 17 takes in thus detected value and controls the LD driver 18 to vary the recording laser power in step thus detecting each magneto-optical signal with its laser power. |
