| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup device which smoothly suppresses an influence by stray light, can easily discriminate a recording layer and can suppress the deterioration of a detection signal due to a positional deviation of a sensor. <P>SOLUTION: A spectroscopic element 118 has diffraction regions 118a0 to 118h0, and 118a1 to 118h1. A diffraction direction is set in each of the diffraction regions. A sensor part arranged on a light receiving surface of a photodetector 120 is irradiated with only signal light of BD light passing through the diffraction regions 118a0 to 118h0, but the signal light does not irradiate gaps of the sensor part. This makes it easy to discriminate each recording layer in a disk having a plurality of recording layers. In addition, the focal position of a laser beam can be quickly adjusted to a targeted recording layer because an S-shaped curve by each recording layer is properly formed. Further, when a positional deviation occurs in the sensor part, it is difficult for an output signal of the sensor part to deteriorate. <P>COPYRIGHT: (C)2012,JPO&INPIT |
