DEVICE FOR THE OPTICAL IDENTIFICATION OF SECURITY MARKINGS CONSISTING OF A LIQUID-CRYSTAL MATERIAL

摘要

The invention relates to a device for verifying a security marking containing liquid-crystal material with a cholesteric reflection band. Said device illuminates the security marking by means of an illumination unit comprising one or more spectrally limited light sources and checks the light that is reflected or transmitted by the security marking for circular polarisation in a detection unit. Said device is characterised in that it contains no moving parts for identifying the circular polarisation, or for modifying the colour of the illumination unit.