Method and apparatus for leading-in focus servo by moving the objective lens toward the recording surface at two different speeds

摘要

A focus servo lead-in method is implemented where the focus servo loop is first in an open state. An objective lens located at a position separated by a predetermined distance from the recording surface of a disk is first moved toward the recording surface at a high velocity. At a predetermined time, the moving velocity is decreased to a lower velocity and the focus servo loop is brought to a closed state based on the level of the focus error signal obtained while the objective lens is moving at the lower velocity.