| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical pickup device enabling reproduction of recording information of two types of recording mediums each having a different recording density, by using one only laser diode (wavelength 780 nm). SOLUTION: Between a laser light source 2 and a beam splitter 9, there is installed a liquid crystal element 33 as a means for rotating a plane of polarization. A light beam emitted from the laser light source 2 passes through the liquid crystal element 33 and the beam splitter 9 and parallelized by a collimator lens 14. This parallelized light is made incident on a first light beam selecting means 3 and reflected on a first reflection area 4 which is a flat face, or on a second reflection area 7 which is a recessed face, and this reflected light is made to enter a super-resolution shielding means 31 as a second light beam selecting means. The light beam passed through this second means is made incident on an objective lens 6 and converged on a recording face by the objective lens 6. The selection of the reflection area in the first light beam selecting means is determined by the operation mode of the liquid crystal element 33. |
