DETECTION METHOD OF ASTIGMATISM QUANTITY OF OPTICAL DISK RECORDING AND REPRODUCING APPARATUS, AND ASTIGMATISM CORRECTING METHOD

摘要

PROBLEM TO BE SOLVED: To provide a detecting method of astigmatism quantity of an optical disk recording and reproducing apparatus, in which the recording operation of a signal is performed with a laser beam emitted from a laser diode incorporated in an optical pickup.;SOLUTION: A first spot diameter being a spot diameter of a signal track direction is detected, by comparing RF signal levels obtained by reproducing pits which are recorded in an optical disk and of which the length is different for each change of the defocus values of a focus servo; while a second spot diameter being a spot diameter of a right angle direction for the signal track is detected by comparing the RF signal levels of reproduced signals obtained from the optical disk, in a state in which the tracking servo is made an non-operating state; and the quantity of astigmatism is detected based on a first defocus value being the minimum defocus value of a first spot diameter and a second defocus value being the minimum defocus value of a second spot diameter.;COPYRIGHT: (C)2006,JPO&NCIPI