| 摘要 |
An illumination device comprising an elongate rod (10) or strip of transluce nt material located within a tube (11) to define a gas space (12) therebetween, the rod having a disrupted surface by way of undulation (13) or striation (17), and a light source located at one or both ends of the device to cause light travelling along the rod to exit transversely to its axis. Primary diffusion occurs within the rod by total internal reflection. Secondary diffusion occurs within the gas space, and a substantially uniform light output is generated by the surrounding tube. For longer lengths of rod the striation may be increased within a central region (21, 22) thus to ensure uniforimity of light output throughout the length. If required, a beam of light may be generated by providing a reflector (15, 16) within the gas spac e (12).
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