| 摘要 |
<p>The beacon is used for maritime hazard warning and has a beam of twinkling light provided by a continuously lit lamp. This light source (S) is surrounded by a rotating lens (5) of suitably translucent material. The lens has a curved inner face (2) which does not refract the light rays. The outer face (3d) of the lens has a number of convex faces (6) around its circumference, these being in pairs alternately angled outwards and inwards. The light is refracted into individual parallel beams, corresponding to the number of convex faces, the difference between the refracted and non-refracted angles providing the obscured period.</p> |
