| 摘要 |
An optical pickup according to the present invention includes: a light source 1d for irradiating an optical disk 4 with light; a lens 3 for converging the light onto the optical disk 4; a photodetector 1c having a plurality of detection regions 1cf, 1ct for detecting light which is reflected from a signal surface of the optical disk 4 and converting the light into an electrical signal; a hologram element 1a having a hologram region 1b for guiding the reflected light to the photodetector 1c; and a light-shielding plate 2 for blocking at least a portion of light transmitted through a region of the hologram element 1a other than the hologram region 1b. The light-shielding plate 2 includes a light shielding portion 2b for blocking light, and an aperture 2a for allowing the light to be transmitted therethrough. The aperture 2b is present, above an upper face of the hologram element 1a, in a region including the hologram region 1b, and a center position of the aperture 2b is shifted from a center position of the hologram region 1b.
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