| 摘要 |
PURPOSE:To contrive miniaturization and thin formation of the device by fixing an optical part, changing only a laser convergent beam in its direction by a mirror and accessing directly in the radial direction of a disk. CONSTITUTION:A beam from a relay lens 14 is changed in its direction by approximate 90 deg. by a galvanomirror 16, and is afterward transmitted through a condenser lens 17 and changed again in its direction by a draw prism 18, and then its spot is formed on the disk 19. Now, since the galvanomirror 16 is constituted to be capable of changing its angle by a electromagnetic means or a piezoelectric means, the tip of the laser beam can widely be swung on the disk in the radial direction. Thus, focusing of the laser spot is performed by single-axial driving of the relay lens 14 and the tracking is by changing of the angle of the galvanomirror 16, and then only the tip part of the laser is widely swung on the disk. By this method, since even a movable part is suppressed to a min., and can be installed in the fixed optical part, high speed access of light in itself as the light itself is emitted into the air is feasible in a compact device. |
