| 摘要 |
PROBLEM TO BE SOLVED: To obtain a laser driving control circuit which drives a laser diode for recording and reproduction and which has a simple circuit constitution. SOLUTION: This circuit is provided with a first current source 192 outputting a first current value regulating the maximum output level of a laser diode 18 at the time of recording, a high frequency oscillation circuit 196 outputting a high frequency current, a switching circuit turning the oscillation of the circuit 196 on/off and a second current source 194 outputting a second current regulating the minimum output level of the laser diode 18 at the time of recording so that widths of the laser oscillation threshold current of the diode 18 and the second current value become narrower than the width of the half crest value of the high frequency current. Then, at the time of reproduction, the reading of information from an optical disk is performed by driving the laser diode 18 while superposing the high frequency current on the minimum output level of the second current source when the oscillation circuit 196 is turned on by the switching circuit and at the time of recording, information are written on the disk by modulatingly driving the diodes 18 with the first and the second current values in a state in which the high frequency oscillator circuit is turned off by the switching circuit. |
