Patent ID: 6163512
Filing Date: 2000-12-19
Classification: G11B

Abstract:
A focus jump control apparatus of a multi-layer recording medium having at least two recording layers, comprising:a focus driving unit that moves an object lens vertically with respect to the recording layers in response to a request for a change of a vertical focus position for the multi-recording medium;a level holder for responding to an output of the focus driving unit to prevent further vertical movement of the object lens and to maintain an object lens driving voltage for a fixed time when the object lens reaches a position corresponding to the request for the change of a vertical focus position;an adder that receives a signal outputted from the level holder and a focus error signal outputted from an object lens driving coil after the vertical movement of the object lens is prevented by the level holder, and that outputs a signal of operation result thereof; anda servo controller that controls the vertical position of the object lens with respect to the recording layers in accordance with the signal of operation result thereof.