Patent ID: 7911922

Claim:
An optical-integrated unit for reading and/or writing information from/onto an optical record medium, comprising: a light source emitting a light beam of a first wavelength and a light beam of a second wavelength different from said first wavelength to said optical record medium; a first grating diffracting the light beams of said first and second wavelengths reflected by said optical record medium; a second grating passing the light beam of said first wavelength coming from said first grating, and diffracting the light beam of said second wavelength coming from said first grating; and a light receiving element receiving, on a common region, the light beam of said first wavelength passed through said second grating and the light beam of said second wavelength diffracted by said second grating, wherein said second grating causes a 0th diffracted beam of the light beam of said first wavelength to epi-illuminate a light receiver of said light receiving element, does not cause ±1st diffracted beams of the light beam of said first wavelength to epi-illuminate the light receiver of said light receiving element, causes a +1st diffracted beam of the light beams of said second wavelength to epi-illuminate the light receiver of said light receiving element and does not cause 0th and −1st diffracted beams of the light beam of said second wavelength to epi-illuminate the light receiver of said light receiving element.