| 摘要 |
<P>PROBLEM TO BE SOLVED: To detect accurately only aberration arising on a forward path of light proceeding to an optical recording medium without being affected by aberration arising on a backward path returning from the optical recording medium, and to realize good aberration correction based on the detected result. <P>SOLUTION: In an optical recording medium driving device, a diffraction optical element 225 is disposed on an optical path extending from a light source 212 to an objective lens 220 in order to branch luminous flux into a main luminous flux and a pair of sub-luminous-fluxes. Each sub-luminous-flux has fixed aberration having polarity being inverse to each other, and forms a pair of sub-spots at a position being separated from the main spot on a signal recording layer of an optical disk 102. Aberration detection is performed on the basis of diffraction intensity distribution in the reflected luminous flux of the pair of sub-luminous-fluxes from the optical disk 102, and aberration correction is performed by generating aberration being of inverse polarity and the same kind as aberration detected by an aberration correction element 228. <P>COPYRIGHT: (C)2004,JPO&NCIPI |
