Patent ID: 6721244
Filing Date: 2004-04-13
Classification: G11B

Abstract:
A focusing servo pull-in apparatus involving an objective lens for converging light beams emitted from a light source on a data storage medium, and a focusing actuator transferring said objective lens in a direction of optical axis, a focusing servo pull-in operation being effected by driving said objective lens in the direction of optical axis, comprising:a means for outputting a focusing search control signal that transfers a position of focusing point in said light beams up to a position wherein a focusing servo operation of said storage medium can be made; a means for outputting a focusing jump control signal that transfers said position of focusing point in the light beams from a substrate surface of said storage medium to a recording film surface; a means for outputting a focusing servo control signal that allows said position of focusing point in the light beams to follow the substrate surface or the recording film surface of said storage medium; a control means for controlling a focusing servo pull-in operation by switching said focusing search control signal, said focusing jump control signal, and said focusing servo control signal to select a signal to be applied to said focusing actuator; and said control means searching a position of focusing on a substrate surface by means of said focusing search control signal, whereby a focusing servo is pulled in a substrate surface of said storage medium, and then, the position of focusing point in the light beams is transferred to the recording film surface of said storage medium to effect the focusing servo pull-in operation.