Patent ID: 7002892
Filing Date: 2006-02-21
Classification: G11B

Abstract:
1. An optical pickup apparatus, comprising: a laser beam source; a polarization plane rotating means adapted to rotate a polarization plane of light emitted from the laser beam source; a first light-selection means adapted to select light from the polarization plane rotating means according to a polarization plane of the light, the first light-selection means includes a reflection mirror composed of a plano-concave lens whose flat side has a polarization filter film adapted to selectively transmit or reflect light according to an angle of the polarization plane of the light, and whose concave side has a reflection film adapted to reflect the light irrespective of the angle of the polarization plane of the light; a second light-selection means adapted to select light from the first light-selection means, the second light-selection means is a super-resolution cut-off filter configured such that a polarization filter film of a dielectric multi-layer film is formed on a transparent substrate; an objective lens adapted to converge light from the second light-selection means onto a surface of a recording medium of two types having respective recording densities; and a photodetector adapted to detect light reflected from the recording medium, wherein the laser beam source is applicable to a wavelength only suitable for a recording medium of less recording density between the two types of recording medium.