| 摘要 |
<p>The traffic lights are contained in a single casing having a translucid front face. The casing contains at least three different coloured electrical light sources. Each light source is formed from a luminescent tube coloured red, orange or green. The tubes have the form of a loop whose ends are closed near to each other. The red tube surrounds the orange tube and the oranged tube surrounds the green tube. The system can also have three additional tubes which can be substituted fro each of the principal tubes. The additional tubes are connected in parallel with the corresponding principle tubes.</p> |
