| 摘要 |
<p>In a system to identify a substance eg a type of plastic in a recycling system, a sample 22 is illuminated with ultraviolet light 24 and the induced fluorescence is detected. An image relating to the intensity of the detected fluorescence is stored and compared to reference data to allow the substance to be identified. The plastic may be impregnated with a plurality of fluorescent tracers to produce a characteristic fluorescence for that plastic type. Also disclosed (figure 7) is a filter comprising a plurality of mirrors arranged on a circular frame which mirrors are transparent to particular wavelengths and reflective to others to create a beam having a predetermined spectral characteristics and an output direction that is rotated with respect to the input direction.</p> |
