| 摘要 |
<P>PROBLEM TO BE SOLVED: To secure good characteristics for a light receiving element when a plurality of laser beams different in wavelength are used. <P>SOLUTION: A light emitting element 9 having a plurality of emission points 9a to 9c for emitting laser beams different in wavelength according to a type of a disk recording medium 100, and a light receiving element 14 having a light receiving surface for receiving the return light of a laser beam emitted from the light emitting element and reflected on the disk recording medium are provided. The light receiving elements are moved to positions in which the laser beams of wavelengths reflected on the disk recording medium are made incident on the light receiving surface. <P>COPYRIGHT: (C)2006,JPO&NCIPI |
