| 摘要 |
An attachment for a light unit, which attachment comprises light-detecting means adapted to generate an output signal corresponding to the intensity of light incident thereon, and adjustable attaching means for removably attaching said attachment to an existing light unit such that the light detecting means are positioned within a beam of light emitted by the light unit when operated and are adapted to detect light that is directed towards the light unit, said attaching means being adjustable to allow the attachment to be selectively fitted to a range of different existing light units. Particularly, said light sensing means are adapted to sense light from the light unit that is retro-reflected back towards the light unit. |
