OPTICAL INFORMATION RECORDING MEDIUM EXAMINING METHOD, EXAMINING DEVICE, OPTICAL INFORMATION RECORDING MEDIUM, AND INFORMATION RECORDING METHOD

摘要

A method for inspecting an optical information storage medium includes the steps of: irradiating the storage medium with a laser beam and rotating the medium by a constant linear velocity control technique by reference to the radial location at which the laser beam forms a spot on the medium; changing the rotational velocities according to the radial location on the medium between at least two linear velocities that include a first linear velocity Lv1 and a second linear velocity Lv2 higher than the first linear velocity Lv1; generating a focus error signal and/or a tracking error signal based on the light reflected from the medium; performing a focus control and/or a tracking control on the laser beam that irradiates the medium based on the focus and/or tracking error signal(s); and passing the branched outputs of control loops for the focus and/or tracking error signal(s) through predetermined types of frequency band-elimination filters for the focus and/or tracking error signal(s) to obtain residual errors of the focus and/or tracking error signal(s) and comparing the residual errors to predetermined reference values.