DOCUMENT SECURITY METHOD AND DEVICE INVOLVING THE GENERATION OF MULTIPLE IMAGES

摘要

A new system for security and document authentication is described. The system is based on a transparent element on which more than one image is shown, depending on the way the element is observed. The system is based on cells or sheets of liquid crystal doped with one or more dichroic dyes. The images are obtained by means of a polarizer, and can be printed on a very thin sheet (µm or tens of µm) of polymer material. Moreover, the images can show grayscales or colors. Electric signals are not required either on manufacturing or in regular use.