| 摘要 |
<p>An apparatus for indicating if a security document comprising one or more specified characteristics, said apparatus comprising an effect sensing device responsive to a spontaneous and/or stimulated effect influenced by: a property of at least one reference layer in a multilayer polymer film substrate of said security document; and a location of said at least one reference layer relative to other layers within said multilayer polymer film substrate. The effect sensing device is arranged to output, to a processor of the apparatus, a sensed effect profile representative of said spontaneous and/or stimulated effect as sensed. The processor derives a first data profile from the sensed effect profile, compares the first data profile with a second data profile representative of a specified effect profile and produces an authentication signal representative of a match or otherwise between the data profiles. The apparatus may be operable to determine the thickness of the reference layer and the depth of the reference layer in the substrate. The reference layer may comprise a taggant and the apparatus is able to determine whether the taggant is contained within a layer of the multilayer film substrate or within a surface coating of the film substrate.</p> |
