| 摘要 |
PROBLEM TO BE SOLVED: To perform good information signal writing/reading with respect to an optical recording medium even when aberration is generated by the manufacturing error, the secular change or the temperature change of each optical component or the optical recording medium. SOLUTION: As luminous flux emitting means for emitting plural luminous fluxes different in the amount of aberration to an optical disk 50, a light source 21, a diffraction optical element 23 and an objective lens 25 are included. As signal quality detecting means for detecting the quality of a reproducing signal obtained from the optical disk 50 by each luminous flux, a photodetector 28, and a control circuit are provided. |
