Patent ID: 8335136
Filing Date: 2012-12-18
Classification: G11B

Abstract:
1. An optical pickup apparatus including: a first laser unit including a first light source for emitting a first laser beam; a second laser unit including a second light source for emitting a second laser beam whose wavelength is longer than that of the first laser beam, and a third light source for emitting a third laser beam whose wavelength is longer than those of the first and second laser beams; and a photo detecting device including a first photo detector for receiving the first and second laser beams, and a second photo detector for receiving the third laser beam, in which the first, second and third laser beams selectively emitted from the light sources of the first and second laser units are guided to a common optical path by a beam splitter, and are thus guided to various information recording media fit for the laser beams, wherein the first photo detector provided in the photo detecting device comprises: a first light receiving region for receiving a zero-order beam which is produced by diffracting one of the laser beams; a second light receiving region, located adjacent to the first light receiving region, for receiving a plus first-order beam which is produced by the diffraction; and a third light receiving region, located adjacent to the first light receiving region and opposed to the second light receiving region, for receiving a minus first-order beam which is produced by the diffraction, wherein a light-reception prohibiting area for rejecting reception of the laser beam is provided in a corner portion of each of the second and third light receiving regions, which is closer to the first light receiving region.