| 摘要 |
An optical pickup apparatus is provided to reduce the number of components forming an optical path and minimize assembly clearance of relative displacement of each component since each component has multiple functions. An optical pickup apparatus comprises a light source(20), a diffraction-type polariscope(22), a collimator lens(26), a circular polarizer(28), an objective lens(30), a photodetector(36), a beam splitter(24), and a sensor lens(34). The light source generates light of different wavelengths. The diffraction-type polariscope diffracts the light from the light source to split the light, and selectively shifts polarization direction. The collimator lens makes the light from the polariscope into parallel light. The circular polarizer makes the light from the collimator lens polarized in circle. The objective lens receives the circularly polarized light and illuminates the light on a recording medium. The photodetector receives the light reflected from the recording medium to reproduce a signal recorded on the recording medium. The beam splitter is installed between the diffraction-type polariscope and the collimator lens for splitting incident light and transmitting toward the recording medium and photodetector. The sensor lens condenses the light transmitted by a disk(32) onto a photodetector in the form of a spot.
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