| 摘要 |
An optical pickup apparatus according to an embodiment of the invention includes two or more light sources (21, 23, 121, 123, 125), an objective lens (31) which condenses the light beam having the predetermined wavelength output from each of the light sources to a recording layer of a recording medium, and captures a light beam reflected on the recording layer of the recording medium, a polarization control element (39) arranged between the light sources and the objective lens, to optimize directions of polarization of the light beam having the predetermined wavelength output from the light source and the light beam reflected on the recording layer of the recording medium, in accordance with the wavelength thereof, on the basis of a voltage to be applied, a photodetector (43) which receives the reflected light beam captured by the objective lens and outputs a predetermined signal, and a polarization control circuit (6) which varies the direction of polarization set by the polarization control element, in accordance with the output of the photodetector.
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