| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device that can increase a spot diameter of each of three laser beams each having different wavelengths on a light-receiving surface of a photodetector when the three laser beams are emitted from one semiconductor laser.SOLUTION: A semiconductor laser 101 houses light emission parts 101a, 101b, 101c in the same package, and emit BD light, DVD light and CD light in the same direction. A DOE 109 matches an optical axis of the BD light to an optical axis of the DVD light so that the BD light having the largest numerical aperture and the DVD light having the second largest numerical aperture are superimposed on a photodetector 111. This increases the size of a sensor of the photodetector 111 to thereby increase spot diameters of laser beams. |
