Patent ID: 6996050

Claim:
An optical pickup apparatus for reading and recording information on a recording medium, the apparatus comprising: a laser beam source; a laser beam selecting means adapted to selectively pass and block a laser beam in accordance with a polarization plane of the laser beam; an objective lens; a polarization plane rotating means disposed between the laser beam selecting means and the objective lens, and adapted to rotate a polarization plane; and a photo-detector adapted to detect a reflected laser beam from two types of recording media having respective recording densities different from each other, wherein the laser beam selecting means is a super-resolution cut-off filter comprising a light-transmissible substrate, and a polarizing filter film made of a dielectric multi-layer, formed at a central portion of a side surface of the light-transmissible substrate, and adapted to selectively pass and block a laser beam in accordance with a polarization plane of the laser beam.