| 摘要 |
PROBLEM TO BE SOLVED: To solve such a problem that tracking servo is released due to reduction in DPP signal amplitude during eccentricity of a disk, in a DPP method by three beams.SOLUTION: The optical pickup includes: a laser light source emitting a light beam; an light branching element branching the light beam to at least three light beams of 0 order light and ±primary order light; an objective lens converging three light beams on an optical disk; and a photodetector receiving three reflected light beams from the optical disk. The eccentricity signal is generated by subtraction processing of a push-pull signal generated from a light receiving region of the +primary order light and a push-pull signal generated from the light receiving region of -1st order light. |
