| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device and an optical disk device, wherein linearlity of a focus error signal is high, even for an optical disk having a plurality of layers of information recording surfaces. <P>SOLUTION: This optical pickup device is provided with a laser light source 1, a hologram 3, having a focus region 23 and tracking region 24, an objective lens 6, and a photodetector 4 having focus and tracking photodetection parts 4a and 4b, respectively. In the hologram 3, the inside of the boundary virtual line 20 of a predetermined shape smaller than the outer periphery of the hologram 3 with O as the center of the hologram is set as a focus region 23, and the outside of the boundary virtual line 20 is set as a tracking region 24. <P>COPYRIGHT: (C)2008,JPO&INPIT |
