| 摘要 |
PROBLEM TO BE SOLVED: To start a focus servo operation by preventing a focus servo operation from being started due to the erroneous detection of reflection on the surface of an optical disk, thereby accurately detecting the position of a signal recording surface. SOLUTION: A control means 20 is provided with: a first identification signal generation means 25 for comparing a focus error signal with a first threshold value with a first threshold value to generate a first identification signal; a second identification signal generation means 26 for comparing a total light amount signal with a second threshold value to generate a second identification signal; and a third identification signal generation means 33 for generating a third identification signal based on the first and second driving voltages of an actuator positioned within a predetermined range from the surface of the optical disk and a signal recording surface. In the falling edge of the first identification signal after the rising of the third identification signal and the rising of the second identification signal, a signal supplied to an actuator driving means 21 is switched from a focus pull-in signal to a focus error signal. COPYRIGHT: (C)2007,JPO&INPIT
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