Patent ID: 6917571

Claim:
An optical disk drive comprising: an optical pickup for emitting a laser to an optical disk as a recording medium, and signal processing a reflected light from the optical disk; a servo error signal generation means for generating a servo error signal of a focusing and tracking servo system from the reflected light; an offset detection means for detecting an offset, which occurs in the servo error signal due to defocusing or detracking of an objective lens in the optical pickup, and obtaining an offset adjustment value for canceling the offset; an offset adjustment means for adding the offset adjustment value to the servo system to cancel the offset of the servo system, which is detected by said offset detection means; a gain adjustment means for adjusting the gain of the servo system; a laser power switching means for changing the power of the laser emitted from the optical pickup; a command means for outputting an offset adjustment command, a gain adjustment command, and a laser power switching command to said offset adjustment means, said gain adjustment means, and said laser power adjustment means, respectively; a storage means for holding an offset adjustment value, a gain adjustment value, and a laser power, which are to be set in said offset adjustment means, said gain adjustment means, and said laser power adjustment means, respectively; and a driving means for receiving the servo error signal, and outputting a driving signal for controlling said optical pickup, wherein a first gain adjustment value and a first offset adjustment value to be set in the servo system are stored in said storage means, when the laser power emitted from said optical pickup is a first laser power, wherein a second gain adjustment value to be set in the servo system when a second laser power is emitted from said optical pickup is obtained by arithmetic operation on the basis of the first gain adjustment value, the second gain adjustment value is set in said gain adjustment means, and a second offset adjustment value for canceling an offset which occurs in the servo system is obtained, and then, the second laser power, gain adjustment value, and offset adjustment value are stored in said storage means, and wherein when the first laser power is switched to the second laser power during the actual operation, switching of the laser power and switching from the first gain adjustment value and offset adjustment value to the second gain adjustment value and offset adjustment value are carried out simultaneously.