| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup apparatus by which both a focus error signal and a tracking error signal can be smoothly formed even if a track direction on a photodetector is not a direction forming an angle of 45° with respect to the deformation direction of a beam spot by astigmatism. <P>SOLUTION: When a swing angle α does not satisfy a relation of α=45° in an optical system in Fig. 2, for example, and as a result, the track direction on the photodetector 16 is not the direction forming the angle of 45° with respect to the deformation direction of the beam spot by astigmatism, division lines of a quadripartite sensor are made to approach the direction forming the angle of 45° to the deformation direction of the beam spot nearer than an intermediate direction between these two directions. Thereby, both the focus error signal and the tracking error signal (a push-pull signal) can be smoothly formed. <P>COPYRIGHT: (C)2007,JPO&INPIT |
