| 摘要 |
PURPOSE:To attain the miniaturization, light weight, and low cost of a light pickup device. CONSTITUTION:Glass plates 14 and 15 arranged to be inclined to an optical axis are provided between a semiconductor laser 11 and a condenser optical system composed of a collimate lens 12 and an objective lens 13. A 1/2 wave length plate or a polarizing plate 18 is provided between the semiconductor laser 11 and the glass plate 14. The polarizing direction of the emitted light of the semiconductor laser 11 is adjusted by the 1/2 wave length plate or the polarizing plate 18. The emitted light radiated from the semiconductor laser 11 is condensed on an optical disk 20 by the condenser optical system. A reflected light from the optical disk 20 is condensed by the condenser optical system, reflected by the glass plates 14, 15, and received by photodetectors 21, 22 through photodetecting elements 31, 32. A data reading signal, tracking error signal, and focusing error signal are prepared based on the output signals of the photodetectors 21, 22. |
