| 摘要 |
<P>PROBLEM TO BE SOLVED: To accurately separate reflected light beams from the two recording layers of an optical disk. <P>SOLUTION: Return luminous fluxes containing a reflected light from a first recording layer and a reflected light from a second recording layer are made a converged light by a converging optical element 58, at least one photodetector PD is arranged between the converging position F1 of the reflected light of the first recording layer and the converging position F2 of the reflected light of the second recording layer contained in parts of the converged light, and the photodetector is provided with a light receiving part for receiving the reflected light from the first recording layer and a light receiving part for receiving the reflected light of the second recording layer. Thus, the reflected light beams from the first and second recording layers are individually obtained without any mutual interferences. That is, the reflected light beams from the two recording layers of the optical disk are accurately separated. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
