| 摘要 |
PURPOSE:To attain miniaturization, light weight, and low cost of an optical pickup device. CONSTITUTION:A grating element 14 arranged to be inclined to an optical axis is provided between a semiconductor laser 11, and a condenser optical system constituted of a collimate lens 12 and an objective lens 13. A grating 16 is formed on a transparent substrate 15 in the grating element 14. Radiating light emitted from the semiconductor laser 11 is condensed on an optical disk 20 by the condenser optical system. Reflected light from the optical disk 20 is condensed by the condenser optical system while one part is reflected by the transparent substrate 15, received by a photodetector 21, the other part is diffracted by the grating 16, and received by a photodetector 22. A data reading signal, tracking error signal, and focusing error signal are prepared based on the output signals of the photodetectors 21 and 22. |
