| 摘要 |
PURPOSE:To avoid the sticking of the external dust, etc., to a convergent lens by providing a shutter as if it covers the convergent lens and opening and closing properly the shutter in accordance with the opening/closing signal. CONSTITUTION:The shutter 1 is properly opened/closed by the shutter opening/ closing signal. Thus the surface of the convergent lens is protected from the outside as long as the shutter 1 is kept closed. While the shutter 1 is opened by the opening/closing signals in the recording/reproducing mode of information. Then the light radiated from a light source is converged by the lens 5 and irradiates an information recording medium without causing such a case where the optical path is interrupted by the shutter 1. When the recording/reproducing mode of information is over, the shutter 1 is kept closed by the shutter opening/ closing signal. Thus the lens 5 is protected again from the outside to avoid the sticking of the dust, etc., to the lens 5. |
