| 摘要 |
When performing recording/reproduction of information for a given recording layer of an optical disc having three recording layers, influences of reflected light from other recording layers are reduced or removed, thus making it possible to obtain a more stable RF signal or focus error signal. An optical pickup device includes a light source, a collimator lens, an objective lens, a photodetector, and a light shielding member. Among the recording layers of the optical disc, a first layer and a second layer adjoining each other are disposed in the order of the first layer and second layer from near the objective lens. The light shielding member is disposed at a position satisfying the condition d>d1 to block a part of reflected light from the second layer when light is converged on the first layer, where d is an optical path length from the photodetector to the light shielding member; and d1 is a distance from the photodetector to a position at which reflected light from the second layer becomes focused between the collimator lens and the photodetector.
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