| 摘要 |
PURPOSE: To miniaturize a device and to reduce a cost by providing first, second polarization separating means instead of a conventional beam splitter, and a Wollaston prism. CONSTITUTION: The first polarization separating means 12 is provided on one surface of a base material 41 arranged between a light source 11 and an objective lens 13, and separates a light beam from the light source 11 and a return light beam from a recording surface of a magneto-optical recording medium MO through the objective lens 13 in the radial direction of the magneto-optical recording medium MO. The second polarization separating means 14 is provided on the other surface of the base material 41, and separates the return light beam separated by the first polarization separating means 12 to three light beams of zero-order diffracted light and±1st-order diffracted light to send them to respective parts 15a, 15b of a photodetector 15. The photodetector 15 detects a focusing error signal based on respective output signals of the separated light receiving surfaces 15a, 15b on which the zero-order light is made incident, and further, detects a tracking error signal by a difference of the signals based on two pieces of light beams by the±1st-order light. Thus, the first, second polarization separating means are constituted integrally.
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