| 摘要 |
<P>PROBLEM TO BE SOLVED: To enhance the reproduction accuracy of information from an optical disk. <P>SOLUTION: This optical disk device first adjusts a distance between the focal point of a reference light beam and the focal point of an information light beam to a substantially equal distance to the depth of a target position, when a pull-in operation is performed; calculates a focus error signal and a sum signal, while making an objective lens reciprocate in a focal direction; and can start focus control, in an appropriate state where the focus error signal draws a S-shaped curve with sufficient amplitude, by starting the focus control, on the basis of the focus error signal, when a trigger signal generated on the basis of the sum signal goes into a low level. <P>COPYRIGHT: (C)2010,JPO&INPIT |
