| 摘要 |
<p>Apparatus for detecting the presence of a modifier ingredient, such as an UV stabiliser, in a substrate surface, for instance of PVC, includes a UV generator (12) which produces UV radiation which is directed to a desired area (22) of the substrate surface (16). An image of the desired area of the surface is formed by a lens (23) at an image plane on a detector (26) which is arranged to detect the fluorescent radiation produced by the substrate surface. The detector (26) generates a signal in response to the fluorescent radiation incident thereon which is representative of the degree to which the substrate surface has been modified. <IMAGE></p> |
