| 摘要 |
PURPOSE:To prevent the track formed newly on the disc from being crossed or laminated on the track formed with recording in advance, by automatical control the recording light source and the driving unit for the light source according to the signal reproduced from the disc. CONSTITUTION:The light L from the semiconductor laser 101 of the recording and reproduction optical unit 10 is focussed into a fine diameter, radiated on the optical recording disc 11, recorded and reproduced, and the light power of the light source is set for the power at signal reproduction and signal recording, the power at reproduction is irradiated in advance to the signal recording section of the disc 11, the reflection light of disc is detected at the photodetector 105 to detect the presence of the envelope of the reproducing signal, and if the reproduced light is in crossing with the track pre recorded or is abnormally close to it, the envelope signal is output according to the part, and control is made at the semiconductor laser driving circuit 20 based on the envelope signal. |
