| 摘要 |
<P>PROBLEM TO BE SOLVED: To quickly and highly accurately discriminate a recording layer on which the converged beam of an optical pickup head is focused in recording/reproducing of a multilayer optical disk. <P>SOLUTION: A diffraction optical element 3 divides a light from a light source 1 to generate optical beams corresponding to at least the number of information recording layers of an optical disk 7 so that the interval of optical beams in an optical axis direction is the same as the information recording layer interval of the optical disk 7, and light receiving components 12a and 12b individually receive the return lights of optical beams. Then, based on received light levels detected by the light receiving components 9, 12a and 12b, the information recording layer on which a main beam is focused is discriminated. <P>COPYRIGHT: (C)2008,JPO&INPIT |
