Patent ID: 7126899
Filing Date: 2006-10-24
Classification: G11B

Abstract:
1. An optical recording medium handling device comprising: an objective lens unit focusing a spot of light onto an optical data-recording medium having a plurality of data-recording layers; a driving unit moving the objective lens unit in the direction of the optical axis to move the focal point of the spot of light between the plurality of data-recording layers; a spherical aberration correcting unit correcting the spherical aberration occurring in transparent cover layers provided for each data-recording layer and having different thicknesses; a reflected-light detecting unit detecting the spot of light reflected by the optical data-recording medium; and a control unit switching between acceleration and deceleration of the driving unit based on the rate of change of a reflected-light intensity signal detected by the reflected-light detecting unit, when an interlayer movement is performed, the interlayer movement being the movement of the focal point of the spot of light from one data-recording layer to another data-recording layer, wherein the objective lens unit includes a two-group objective lens with high numerical aperture.