| 摘要 |
An apparatus for verifying, under ambient lighting conditions, the authenticity of an optical security mark on an item, the mark comprising a luminescent material which absorbs light within a first predetermined range of wavelengths and emits luminescence within a plurality of other predetermined wavelength ranges with a predetermined characteristic time response. The apparatus distinguishes the luminescence of the mark from fluorescence the item may have by distinguishing the slower luminescence decay rate of the security mark from the faster decay rate of the inherent fluorescence. The apparatus comprises an optical arrangement, having an illumination assembly and a luminescence detector assembly, and a signal processor assembly, all contained in a single housing. The illumination assembly and the luminescence detector assembly have a common focusing lens and are arranged along a common axis to illuminate the security mark and to detect emitted light from the security mark in a retro-reflective manner.
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