DOCUMENT SECURITY METHOD AND DEVICE INVOLVING THE GENERATION OF MULTIPLE IMAGES

摘要

The invention relates to a novel document security and authentication system based on a transparent element on which more than one image appears depending on the manner in which said element is viewed. The system is based on cells or sheets of liquid crystal doped with one or more dichroic dyes. The images obtained with the aid of a polarizer can be printed onto a very thin (µm or 10 tens of a µm) sheet of polymer material; said images may also be in greyscale or in colour. There is no need to apply electrical signals during the production or use thereof.