| 摘要 |
<p>A detection device comprising a longitudinally extending hollow body (7) having a light input position (11) located transversely between the ends thereof, one end comprising an output or viewing window end (10) and the other end comprising an output/input window end (12). Light transmissive fibres are provided to connect between the light input position (11) and the output/input window end (12) and between such output/input window end (12) and the viewing window end (10). Means (17, 18) are provided to facilitate varying the angle of incidence of light rays impinging on the fibres (21) located at the light input position (11) so as to facilitate focusing the length of focus of light rays emitted from the fibres (22) at the output portion at the output/input window end (12) to be reflected back to the fibres (23) of the input portion at the output/input window end (12).</p> |
