| 摘要 |
<P>PROBLEM TO BE SOLVED: To restrain the offset of a TE signal and realize precise tracking control in a simple configuration. <P>SOLUTION: Light emitted from a light source 22 is diffracted into one main beam M and two sub-beams S1 and S2, and the sub-beams S1 and S2 are made incident on an objective lens 26 at a critical angle θ and converges on an optical recording medium 21. The critical angle θ is fixed so that maximum values of wave front aberrations (Wm) of the sub-beams S1 and S2, generated by the convergence by the objective lens 26 on the optical recording medium 21, are larger than 1/4 of the wavelength (λ) of the light emitted from the light source 22 (Wm≥λ/4). In such an optical pickup device 20, a good TE signal whose offset is restrained in a tracking servo can be obtained, since sub-beam spots are formed largely distorting so that they straddle a plurality of track grooves and lands. <P>COPYRIGHT: (C)2004,JPO |
