Patent ID: 7480228
Filing Date: 2009-01-20
Classification: G11B

Abstract:
1. An optical disc apparatus using an optical pickup, wherein the optical disc comprises a light source for outputting a first laser beam and a second laser beam each having a different wavelength corresponding to a first optical disc and a second optical disc each having a different specification, and a common optical system for allowing the first laser beam and the second laser beam to converge on the optical disc and guiding the reflected beam from the optical disc to one light receiving part; the optical system includes a diffraction optical element on which two diffraction gratings respectively for separating the first laser beam and the second laser beam into three beams of a main beam by 0 the diffraction optical element has two flat surfaces which are parallel to each other, and on the optical disc, the first diffraction grating is formed on one surface and the second first diffraction grating is formed on the other surface so that a direction in which a straight line binding +1