| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup and a playing back device for an optical disk with which a focus error signal is obtained with high precision. SOLUTION: Diffracted light beams having predetermined diffraction angles Θ1 and Θ2, respectively, are generated by making light beams which have a first wavelength λ1 and a second wavelength λ2, respectively, which are emitted from light sources 1a and 1b, respectively, and reflected on signal recording face of an optical disk, incident on a diffraction grating 9, and the light receiving face of a photodetector is arranged on the intersection of the optical axes of the diffracted light beams, thus the light beam having the first wavelength λ1 and the light beam having the second wavelength λ2 are made incident on a photodetector 10. |
