| 摘要 |
PURPOSE:To prevent adhesion of dust to an objective lens by fixing a shutter such that the objective lens is exposed only when a semiconductor laser is emitting light. CONSTITUTION:An objective lens driver comprises an objective lens 1, a shutter 6, a magnet 7, a stopper 8 and a pin 9, where a coil 11 is fixed in parallel with the axis of the pin 9. The shutter 6 is moved by means of the magnet 7 and current supply to the coil 11, where the shutter 6 is blocked of its motion in one direction by means of the stopper 8. When a semiconductor laser 3 is emitting light, current is fed to the coil 11 of the shutter 6 so that the shutter 6 rotates in a plane orthogonal to the optical axis of the objective lens 1 and the rotation of the shutter 6 is regulated by means of the stopper 8. When the semiconductor laser 3 stops emission of light, current supply to the coil 11 is interrupted to reset the shutter 6. According to the constitution, dust is prevented from adhering to the objective lens 1. |
