| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical head device capable of accurately tracing a track by preventing incidence of reflected light from an information recording layer which is not a recording/reproducing object on a light receiving part when an optical disk having a plurality of information recording layers is recorded and reproduced, and an optical disk device. <P>SOLUTION: The optical head device includes an objective lens condensing a laser beam on the optical disk, a photodetector 209 detecting the reflected light of the laser beam condensed on the optical disk, and a diffraction element 207 which is disposed between the objective lens and the photodetector 209 and makes the diffracted light of the reflected light from the information recording layer of the recording/reproducing object among information recording layers of the optical disk be incident on a predetermined light receiving element arranged on the receiving surface of the photodetector 209. The diffraction element 207 is divided into a plurality of optical areas 301 to 308, and is arranged so that diffracted light from an optical area not including the center part of an optical axis among the plurality of optical areas is made incident on the predetermined light receiving element, and stray light of any other layers is made not incident on the predetermined light receiving element. <P>COPYRIGHT: (C)2010,JPO&INPIT |
