| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve tracking accuracy of a DPP system using a dual-wavelength laser. <P>SOLUTION: An optical pickup apparatus has: a laser source which selectively emits a first laser beam with a first wavelength and a second laser beam which is parallel to the first laser beam and has a second wavelength; a diffraction grating where a plurality of periodic structures having repetitive concavities and convexities in a direction optically corresponding to a tangential direction of an optical disk are joined so that phases are different from each other in a direction optically corresponding to a tracking direction of the optical disk, the diffraction grating generating a zeroth-order light and a ±first-order diffraction light by diffracting the first or second laser beam; an objective lens which focuses the generated zeroth-order light and ±first-order diffraction light on the same track of the optical disk; and a light detector to which reflective light of the focused zeroth-order light and the ±first-order diffraction light are radiated through the objective lens, and which generates a differential push-pull signal. A direction of a straight line which connects light-emitting spots of the first and second laser beams is inclined with respect to the direction optically corresponding to the tracking direction. <P>COPYRIGHT: (C)2010,JPO&INPIT |
