| 摘要 |
PURPOSE:To heighten the luminance of the luminous flux of a light projecting device, by providing a light intercepting section provided with an opening section which leads the light of a discharge tube to a projection lens. CONSTITUTION:The surface of a discharge tube 1 is coated with a thin film of a conductive metal 5 formed by vapor deposition and a slit section 5a which leads rays of light emitted from the discharge tube 1 to a projection lens 4 is provided on the side of the discharge tube 1 facing the projection lens 4. When a trigger voltage is impressed across a terminal 6 for trigger, the metal 5 works as a trigger electrode. As a result, the distance between the discharge tube 1 and the slit section 5a which leads the light of the tube 1 to the lens 4 disappears and the light emitted from the discharge tube 1 does not drop in luminance. When such light projecting device is used as a distance detector, the intensity of illumination of a distance measuring object can be raised and the distance measuring capacity can be improved. Moreover, if the discharge tube 1 is made to have such a surface that can reflect rays of light, the surface also acts as a reflector and the luminance of the luminous flux emitted from the slit section 5a is further raised. |
