Patent ID: 6256272
Filing Date: 2001-07-03
Classification: G11B

Abstract:
An optical pickup comprising:a first light source having an astigmatic difference and emitting a first laser beam of a first predetermined wavelength toward an optical disc;a second light source emitting a second laser beam of a second predetermined wavelength which is different from the first predetermined wavelength, toward the optical disc;a first beam splitter arranged on a path of the first laser beam emitted from the first light source having the astigmatic difference, for reflecting the first laser beam toward the optical disc;a second beam splitter disposed at one side of the first beam splitter such that it has a predetermined sloping angle, for reflecting the second laser beam emitted from the second light source toward the optical disc and for generating an astigmatism which can offset the astigmatic difference of the first light source when the first laser beam emitted from the first light source passes therethrough;a reflecting mirror for totally reflecting the second laser beam which is emitted from the second light source and reflected by the second beam splitter and the first laser beam which is emitted from the first light source and passes through the second beam splitter;a collimator lens for shaping the laser beams reflected by the reflecting mirror into parallel lights;an objective lens for spotting the parallel light beams shaped by the collimator lens onto the optical disc; anda photodiode arranged at the other side of the first beam splitter for detecting an error signal from the beams which are reflected from the optical disc.