Drive device and method for controlling the same

A drive device, comprising:

• an optical pickup, including:
• a light source;
• an objective lens which converges light from the light source onto an optical disc;
• a drive section which drives the objective lens so as to control focus onto the optical disc;
• and
• a photodetector section which detects light reflected from the optical disc;
• a generation section which generates, based on an optical signal detected by the photodetector section, balance information which represents deviation in a photodetector pattern on the photodetector section in the tangential direction of the optical disc;
• an FE obtaining section which obtains, based on the optical signal detected by the photodetector section, an FE signal which represents an amount of focus deviation of the objective lens relative to the optical disc;
• a TE obtaining section which obtains, based on the optical signal detected by the photodetector section, a TE signal which represents an amount of tracking deviation of the objective lens relative to the optical disc;
• a storage section which previously stores therein relation information which represents relation of a signal difference between the FE signal and the TE signal, at the time of a predetermined operation of the optical pickup, with respect to the balance information;
• and
• a control section which controls the drive section, wherein
• at the time of the predetermined operation of the optical pickup, the control section controls the drive section using the generated balance information, the obtained TE signal, and the previously stored relation information, thereby to adjust the focus of the objective lens.