| 摘要 |
<p>A diffusor for use with a traffic sign or the like which displays an illuminated symbol has a central opaque zone (10) adapted to reduce light transmission through the portion of the symbol on and adjacent to the optical axis of the sign, a second opaque zone (11) on the inner face of the diffusor adapted to transmit more light than the central portion and a third opaque zone (12) on the outer face of the diffusor adapted to transmit more light than the central zone. The second and third zones are not necessarily being in alignment and the third zone may transmit more light than the second zone.</p> |
