| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical head device capable of reducing low-frequency noise at the time of reproducing a super resolution optical disk including a small recording mark lower than a diffraction limit and improving quality of a reproduction signal. <P>SOLUTION: A photodetector 27 of an optical head divice 10 includes a first light receiving surface comprised of a plurality of light receiving elements for receiving a peripheral portion of a return light beam, and a second light receiving surface comprised of a light receiving element for receiving a center portion of the return light beam. The plurality of light receiving elements of the first light receiving surface are disposed at asymmetrical positions with respect to an intersection of two orthogonal division lines on a four-part light receiving surface used in astigmatism method for performing focus control of an objective lens 5 or corresponding division lines, and a center of the return light beam is adjusted to the intersection of the division lines. <P>COPYRIGHT: (C)2012,JPO&INPIT |
