Patent ID: 7643396

Claim:
An output voltage adjusting method for laser power monitoring adopted in an optical disk recording and reproducing apparatus, wherein the optical disk recording and reproducing apparatus comprises an optical pickup including a laser diode for emitting laser light, a laser power monitor circuit including a photodiode for monitoring a laser power of the laser diode, the laser power monitor circuit for converting into a voltage a current flowing through the photodiode that receives part of the laser light emitted from the laser diode, and then outputting the voltage thus obtained, and a laser drive control circuit for keeping the laser power of the laser diode constant by making constant an output voltage of the laser power monitor circuit, the optical pick up for optically writing and reading information to and from an optical disk, the output voltage adjusting method for laser power monitoring comprising: a first step of inputting a pulse signal having a predetermined frequency from an outside to a pulse input terminal used by the laser drive control circuit at a time of recording, and causing the laser diode to pulse-emit light by using a channel used by the laser drive control circuit at a time of recording light emission; and a second step of monitoring an output pulse of the laser power monitor circuit with a signal waveform measuring apparatus, and adjusting an amplitude of the output pulse so that an offset in the output pulse of the laser power monitor circuit is cancelled.