| 摘要 |
PURPOSE:To miniaturize a device by arranging a converging lens, a cylindrical lens and a polarized beam splitter on the optical axis of reflected light from a recording medium and arranging respective two-divided photodetectors in the bus direction of the cylindrical lens and its rectangular direction. CONSTITUTION:The converging lens 6 and the cylindrical lens 7 are arranged on the optical axis of reflected light from the recording medium and the polarized light beam splitter 8 for dividing light flux into two polarized components intersecting orthogonally with each is arranged on the back of both the lenses 6, 7. The two-divided photodetectors, one of them allows the dividing direction of photodetecting elements to almost coincide with the bus direction of the lens 7 and the other allows that to almost coincident with the direction intersecting orthogonally with the bus direction are arranged on symmetrical positions between respective focuses based upon the lenses 6, 7 on respective optical axes divided by the splitter 8. Divided outputs from the photodetectors 9, 10 are computed by a computing element 11 to detect a recording signal and a servo signal. Since the number of components can be reduced, the device can be miniaturized.
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