| 摘要 |
<P>PROBLEM TO BE SOLVED: To control a laser output in forming a pit in real time. <P>SOLUTION: At recording the optical disk, return light receiving signals E, F of a sub-beam 16b are added by an adding amplifier 34 to obtain E+F. A level of E+F in forming the pit is subjected to sample-and-hold to a sample- hold circuit 36, and the level of E+F at the pit non-forming time is subjected to sample-and-hold to a sample-hold circuit 37. The difference α-β between an average value α of the sample-hold value of E+F in forming the pit and an average value β of the sample-hold value of E+F at the pit non-forming time is obtained by a subtraction circuit 40. The deviation between a reference value α<SB>0</SB>-β<SB>0</SB>of α-β being set on a reference value setting circuit 44 and the obtained value of α-β is obtained by a comparator 48. By a laser output control circuit 50, an output of the laser beam in forming the pit is increased/ decreased by a laser output control circuit 50 so as to negate this deviation. <P>COPYRIGHT: (C)2003,JPO |
