摘要 |
<p>A banknote validation arranged to discriminate between real and false banknotes is described. The valuator comprises: a light source arranged to emit light in the non-visible spectrum onto a banknote being validated, the emitted light including an ultraviolet (1O nm to 400 nm) or intra red (800 run-1 00000 nm) wavelength of light; a broadband optical light sensor arranged to sense a relatively broad band of visible light spectrum wavelengths of light emitted by fluorescence from the banknote in response to the banknote being irradiated with the non-visible spectrum wavelengths of light; and an optical filter positioned between the banknote and the sensor and arranged to prevent illumination of the sensor with reflected or transmitted non-fluoresced light from the light source, the optical filter having a−3 db cut off point selected such that the light emitted from the light source, having a wavelength closest to the visible light spectrum wavelengths of light, is filtered.</p> |