Patent ID: 7099085
Filing Date: 2006-08-29
Classification: G11B

Abstract:
1. An optical pick-up apparatus comprising: a light source for emitting laser light in two wavebands; a light-receiving element for receiving laser light which is emitted from the light source and is reflected by an optical recording medium; and a diffraction grating having polarization characteristics between the light source and the optical recording medium by which the laser light emitted from the light source and being incident is transmitted without diffraction when a polarization direction for the laser light is equal to a predetermined first polarization direction and also by which the laser light emitted from the light source and being incident is diffracted when a polarization direction for the laser light is equal to a predetermined second polarization direction, the optical pick-up apparatus performing at least one of processes for reading information of the optical recording medium and recording information on the optical recording medium by irradiating the optical recording medium by the laser light emitted from the light source on the optical recording medium, and the polarization directions of the laser lights in the two wavebands being orthogonal with each other on a position on which the laser light is incident on the diffraction grating, wherein the light source emits the first and second polarization directional laser lights which are parallel to each other, and a half wavelength plate is arranged between the diffraction grating and the light source so as not to have an effect on a polarization direction for the second polarization directional laser light and so as to change a polarization direction for the first polarization directional laser light.