| 摘要 |
PROBLEM TO BE SOLVED: To provide a small optical head device having a small number of parts and capable of performing stable recording/reproducing even when a recording medium has large birefringence in the optical head device used for an optical information recording/reproducing device, etc. SOLUTION: A liquid crystal azimuth rotator 51 is provided between a condenser lens 6 and a 1/4λ wavelength plate 4. The liquid crystal azimuth rotator 51 is designed to be a liquid crystal element whose azimuth rotating angle in the polarizing direction changes from 0 deg. to 90 deg. in accordance with the amount of voltage when a voltage is applied on transparent electrodes stuck to both surfaces. By changing the voltage applied on the liquid crystal azimuth rotator 51 according to the amount of birefringency of a disk 7 to be recorded/ reproduced, a light quantity transmitted through a polarizing beam splitter 3 is made to be maximum and high reliability to the recording/reproduction of a signal is obtained. |
