| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical pickup which has a diffraction element to obtain diffraction light and can obtain desired diffraction light for optical beams of various wavelengths by using only one diffraction element without producing unnecessary diffraction light when optical beams of various wavelengths pass. <P>SOLUTION: The diffraction element 8 in this optical pickup system has liquid crystals, transparent electrodes sandwiching them, electrodes electrically connected to those transparent electrodes, and a liquid crystal controller 21 to control the voltage to be applied to those two transparent electrodes. The diffraction element 8 has two kinds of diffraction areas 19, 20 each producing predetermined diffraction light only for its optical beam different in wavelength, respectively. The pattern formed with transparent electrodes of the diffraction areas 19, 20 are connected to different electrodes 22c, 22a respectively. <P>COPYRIGHT: (C)2007,JPO&INPIT |
