| 摘要 |
PROBLEM TO BE SOLVED: To obtain a control circuit by which the intensity of a read beam can be stabilized even when the speed of a write operation is increased. SOLUTION: A light-intensity monitoring part 14 detects the light intensity of the beam of a semiconductor laser 12 which makes a write beam and a read beam irradiate an optical disk, and it outputs a monitoring signal (a). A sample-pulse(SP) generation part 16 outputs read-output sample pulses (RS pulsed) (b) within the irradiation period of the read beam. A pulse processing part 32 generates delay sample pulses which delay the RS pulses (b) for a prescribed time, and it AND-processes the RS pulses (b) and the delay sample pulses so as to be output as new RS pulses b with reference to a read output S/H part 18. The read output S/H part 8 responds to the RS pulses bnew, and it samples and holds the monitoring signal (a). A read-beam control part 22 controls the light intensity of the read beam so as to become a predetermined reference intensity (g) on the basis of the sampled and held monitoring signal (a). |
