| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical pickup without the need of supplying a power source for liquid crystal rotary driving from the side of a reproducing device by impressing a positive/negative voltage after to a means for rotating a plane of polarization. SOLUTION: A laser beam with wavelength of 635nm emitted from a semiconductor laser 1 is passed through a unit 2 for rotating the plane of polarization and a diffraction grating 9, with a half of the beam reflected by a half mirror 4, then turned to parallel beams by a collimator lens 5, and made incident on an objective lens 6 through a polarization selection unit 3. The laser beam through the objective lens 6 is converged, passed through a substrate 7, and emitted to a signal recording surface 7a. The laser beam reflected by the signal recording surface 7a is then returned through the substrate 7, objective lens 6, polarization selection unit 3, and collimator lens 5; so that the half of the beam is transmitted by the half mirror 4, with the signal detected by an optical detector 8. |
