| 摘要 |
PROBLEM TO BE SOLVED: To prevent beforehand occurrence of functional difficulties (errors) or the like associated with the deterioration in the characteristics caused by double refraction of an optical disk. SOLUTION: In an information processor (47), the peak level of an HF signal obtained by an optical pickup (OPU) when the pickup is located within the inner circumference of an optical disk (DISC) is set as a reference level (I_TOP(in)) and the amount of double refraction (X) of the disk is estimated from the reference level and the peak level of the HF signal (I_TOP(out)) that is measured when the pickup is located at outer circumferential position that is beforehand determined. When the estimated amount (X) is equal to or greater than a preset amount of double refraction, the information processor (47) discriminates the fact that it is the effect caused by the double refraction of the optical disk due to the stress induced by the rotation of the disk and correction is made. COPYRIGHT: (C)2004,JPO&NCIPI
|
