| 摘要 |
<p>[Problem] To provide an optical pickup device capable of suppressing deterioration of a detection signal due to the shift of an objective lens while smoothly suppressing an effect due to stray light. [Solution] A spectroscopic element (H2) has diffractive regions H2a to H2g. Laser beams incident to the diffractive regions H2a to H2f are diffracted into directions Da, Vb, Vc, Dd, Vf, and Vg respectively. A laser beam incident to the diffractive region H2g is diffracted so as not to irradiate the sensor section of a photoelectric detector. The diffractive region H2g is configured such that the vertical length (y3) becomes larger than the horizontal length (x). Hereby, the irradiation region of reflected light from a recording layer focused on the light receiving surface of the photoelectric detector is not likely to overlap the irradiation region of reflected light from other recording layers. Thus, it becomes difficult for signal light and stray light to interfere with each other, whereby the deterioration of a detection signal in the sensor section can be suppressed.</p> |
