| 摘要 |
PURPOSE:To attain miniaturization and light weight of the titled device by providing the 1st face reflecting the light in the direction of a recording medium and the 2nd face splitting the light transmitted through the recording medium into two to an optical element and forming a step to the 2nd face. CONSTITUTION:A light source 2, light receiving elements 3, 4 receiving the light transmitted through a recording medium and the optical element 5 arranged in an optical path from the light source 2 up to the light receiving elements 3, 4, directing the light irradiated from the light source 2 in the direction of the recording medium and directing the light through the recording medium in the direction of the photodetectors 3, 4 are provided. Then the optical element 5 is provided with the 1st face 52 reflecting the light irradiated from the light source 2 in the direction of the recording medium and the 2nd face 51 splitting the light through the recording medium into two, the step 53 is formed between one part and the other part on the 2nd face 51 so as to control both the tracking and focusing with simple constitution. Then number of components is decreased, the constitution is simplified and miniaturization and light weight are attained.
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