| 摘要 |
PURPOSE:To reduce a recording routine such as detection/display and judgement of laser hit at the recording of optical disc and also the end of recording at point of time of generation by comparing an output of a photodetector receiving an optical output of a part from a recording light source at an optional level. CONSTITUTION:Luminous flux irradiated from a recording light source 1 passes through an optical modulator 2 and a modulator 2 and information is recorded on a recording medium 5 by an optical system 4. Simultaneously, a part of the luminous flux is extracted by a beam splitter 6 and received by a photodetector 7. The level of an output E0 of the photodetector 7 is decreased when a hit is generated. This E0 is applied to a (-) input of a comparator 8, and a level dividing the E0 by resistors R1, R2 and R3 is applied to a (+) input through an integration circuit comprising R4, C where the time constant is set sufficiently larger than the hit time. An output of the comparator 8 is fed to a counter 10 to display the frequency of hits on a display element 11 and inform generation of hit by a buzzer 14. |
