| 摘要 |
<P>PROBLEM TO BE SOLVED: To improve precision of tracking control by reducing interference fringes occurring on a spot projected on the light-receiving surface of a light-receiving means to the extent that the influence of the interference fringes can be neglected, while maintaining light use efficiency, without being influenced by a component provided in a light path through which a laser beam passes or causing a shift in a positional relation with the laser beam, even when the tracking control is performed to an optical disk that has a plurality of recording layers in a thickness direction. <P>SOLUTION: An optical pickup device includes: a light source 1 for emitting laser beam; an objective lens 5 condensing laser beam on an optical disk 101 that has a plurality of recording surfaces 101a, 101b; and an OEIC (Opto-Electronic Integrated Circuit) 7 for receiving reflection light from the optical disk 101. A phase modulation part 5a is provided to the almost center part of the surface opposing to the optical disk 101 of the objective lens 5, so that the phase of part of the reflection light passing through the phase modulation part 5a is made to differ from that of the reflection light which does not pass through the phase modulation part 5a. <P>COPYRIGHT: (C)2010,JPO&INPIT |
