FOCUS CONTROL DEVICE AND METHOD, AND FOCUS CONTROL PROGRAM

摘要

A focus control device and method and focus control program for stable focusing even if the defocus of an optical pickup is large. The focus control device is provided with an actuator drive section (56) for controlling the drive of a two-axis actuator (43) so as to focus an objective lens (42) according to an electric signal from the optical pickup (4), a defocus setting section (53) for setting a defocus value used as a reference for the difference between the focal point of the objective lens (42) and the operating point, and a defocus changing section (54) for changing the defocus value to a preset one or zero.