| 摘要 |
In a focus control of an optical disk with a fast reproduction velocity and a large face deflection, the present invention can effect a mistakeless and reliable focus pull-in method. The present invention comprises: means for applying a braking signal to a focus actuator before closing a focus control loop; means for detecting a reversal of a relative velocity between an objective lens performing a focus search operation and an optical disk which effects an up-and-down motion due to the face deflection; and means for detecting the relative velocity between the objective lens and the optical disk from a focus error signal which is detected in each layer of a multi-layer disk. <IMAGE> |
