| 摘要 |
PURPOSE:To reduce the size of optical system and to simplify the adjustment, by providing a mirror which can rotate and move to scan the laser beam to either one of tracking direction or tangential direction whichever the objective lens does not move along. CONSTITUTION:In an optical reproduction system 13, the beam emitted from a laser beam source 14 is linearly polarized and guided to a linearly polarized beam splitter 16 through a diffraction grating 15. The transmissive light is guided to 1/4 wavelength board 18 through a collimater lens 17, and then guided to a movable mirror 19 with being circularly polarized. The mirror 19 is rotated and moved to the direction of arrow Ta so that the laser beam can be scanned to the tangential direction, and the reflected laser beam is projected on an information recording surface 23 of an optical disc 22 through an objective lens 21. The lens 21 can be moved focusing direction and tracking direction Tr. And the laser beam reflected on the recording surface 23 is received by a photoelectric converting element 25. In this way, the optical system 13 can be made small in size and easy in adjustment. |
