Patent ID: 8498189

Claim:
An optical pickup device, comprising: a laser source emitting a first laser beam having a first wavelength and a second laser beam having a second wavelength different from the first wavelength and projected in parallel with the first laser beam; an optical system for impinging the first and second laser beams onto an optical disk that is to be recorded or read; and a diffraction grating placed in an optical path of the first and second laser beams and configured to produce a zero-order laser beam and a ± first order laser beam from each of the first and second laser beams; wherein the diffraction grating includes a first diffraction grating region and a second diffraction grating region having a same pitch as the first diffraction grating region and being laterally offset from the first diffraction grating region, and at least one of the first and a second laser beams are diffracted by both of the first and second diffraction grating regions, and wherein the ± first order laser beam is offset from the zero-order laser beam by 1.5 tracks of a CD, 2.5 tracks of a DVD±R/RW and 1.5 tracks of a DVD-RAM.