Optical pick-up device with error detection using p-wave

Abstract

An optical pick-up device capable of accurately detecting focus errors, tracking errors, magneto-optic signals and pit signals recorded on an optical disc by use of a dichotomous hologram and decreasing the number of optical elements used, thereby achieving a lightness and an improvement in reading rate. The optical pick-up device includes a laser transmission and receipt error detecting unit for detecting an error present at the optical disc, based on size of reproduced beams corresponding to a part of P-wave components of beams reflected depending on optical information recorded on the optical disc, a polarized-beam splitting unit for reflecting all of beams emerging from the collimator lens while being S-polarized and a part of beams emerging from the collimator lens while being P-polarized, and transmitting the remaining part of the P-polarized beams to focus them onto the optical disc via information record/reproduction processing unit, the polarized-beam splitting unit also serving to transmit and reflect beams reflected by the optical disc, and an optical information reading unit for reading the information recorded on the optical disc, based on signals respectively indicative of the sum of and the difference between all the S-wave components and the part of P-wave components of the beams received from the polarized-beam splitting unit.