| 摘要 |
PROBLEM TO BE SOLVED: To stably conduct recording and reproduction by performing a first trial emission before an information recording medium is inserted, storing signals detected by an optical detector in a state where the reflected light beams from the medium are not detected by the detector, performing a second trial emission after the insertion of the medium, storing the detected signals corresponding to the reflected light beams detected by the detector and adjusting the light quantity on the basis of the values of the detected signals. SOLUTION: The first trial emission is conducted while an optical card is not inserted into the device. A constant current source 54 supplies currents to a semiconductor laser (an LD chip) 22 on the basis of the output of a D/A converter 53, the LD 22 is made to emit light, an MPU 3 gradually raises the output of the converter 53 and the setting value DH of the converter 53 is recorded when it is discriminated that the output of a monitor 33 reaches a target value A0. The second trial emission is conducted after the card is inserted. The MPU 3 sets the value DH to the converter 53 and the output A1 of the monitor 33 obtained through an I/V converter 51 and an A/D converter 52 is recorded. Then, driving is conducted so that the output of the monitor 33 becomes A1. |
