| 摘要 |
PURPOSE:To obtain a smooth reproducing signal by providing an optical system for taking out a reflected or transmission light from a magneto-optical recording medium, a beam splitter, a Babinet-Soleil compensator, a 1/2 wavelength plate, an analyzer, a photodetector, and a differential amplifier. CONSTITUTION:A laser light 1 is projected onto a recording medium 7 through a lens 2, a polarizer 3, a beam splitter 4, and a lens 6 of a driving device 5, a reflected luminous flux is split 4, and by a Babinet-Soleil compensator 8 and a 1/2 wavelength plate 9, the polarized state is controlled. As for the element 8, two pieces of wedges of a crystal for turning to the right and left are placed in a shape of parallel plates, a phase quantity is changed by sliding it in the uniaxial direction, and the polarized state which is made into an ellipse by a medium substrate, etc. can be returned to a linear polarized state. Subsequently, the signal component is brought to an amplitude division 10, condensed 11a,11b and detected 12a, 12b, and brought to a differential amplification 13, and thereafter, a disturbance of an envelope of a reproducing signal is smoothed by a prescribed filter 14, and the S/N can be raised.
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