| 摘要 |
An optical pickup device is equipped with a diffraction element ( 8 ) that includes liquid crystal, two transparent electrodes sandwiching the liquid crystal, and a liquid crystal control portion ( 21 ) with electrodes connected electrically to the transparent electrode for controlling a voltage to be applied between the two transparent electrodes. The diffraction element ( 8 ) is provided with two types of diffraction areas ( 19 ) and ( 20 ). Each of the diffraction areas ( 19 ) and ( 20 ) generate predetermined diffracted light only from one of different wavelengths of light beams. The transparent electrodes of the diffraction areas ( 19 ) and ( 20 ) that are patterned are connected electrically to different electrodes ( 22 c) and ( 22 a), respectively.
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