Patent ID: 8462596

Claim:
An optical pickup device for performing recording or reproduction of information by converging light onto an optical disc having three recording layers, the optical pickup device comprising: a light source for emitting light; a collimator lens for converting the light emitted from the light source into substantially parallel light; an objective lens for converging the light having been converted to the substantially parallel light onto the optical disc; a photodetector for receiving reflected light from the optical disc via the collimator lens; and a light shielding member provided in an optical path between the collimator lens and the photodetector for blocking a part of the reflected light and transmitting the rest, wherein, from near the objective lens, the optical disc includes the first layer, the second layer, and a third layer; the light shielding member is disposed at a position satisfying the condition d>d 1 to block a part of reflected light from the second layer when the light is converged on the first layer, where d is an optical path length from the photodetector to the light shielding member; and d 1 is a distance from the detector to a position at which reflected light from the second layer becomes focused between the collimator lens and the photodetector; and the light shielding member is disposed at a position satisfying the condition d≧ 2 ×d 1 ×d 2 /(d 1 +d 2 ) when the light is converged by the objective lens onto the second layer, where d 2 is a distance from the detector to a position at which reflected light from the third layer becomes focused between the collimator lens and the photodetector.