| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical pickup device capable of reproducing optical recording mediums having different thicknesses by making the optical path length from a first light source to a condenser lens larger than the optical path length from a second light source to the condenser lens. SOLUTION: A light source 1 and a light source 2 are arranged so that the optical path length from the light source 1 to a condenser lens 5 is longer than the optical path length from the light source 2 to the condenser lens 5 and scattered lights outputted from the light sources 1, 2 are respectively converged to the focus P1 and the focus P2 on optical recording mediums which are not shown in the figure via a diffraction grating for tripartition 3 and a transmission type hologram element 4. The reflected lights of the focus P1 and the focus P2 are respectively detected by a photodetector 6 and a photodetector 7 via the condenser lens 5 and the transmission type hologram element 4. Thus, the optical pickup device capable of reproducing optical recording mediums having different thicknesses is obtained. |
