IMPROVEMENTS IN SUBSTRATES

摘要

THE PRESENT INVENTION RELATES TO IMPROVEMENTS IN SECURITY DEVICES THAT CAN BE USED IN VARYING SHAPES AND SIZES FOR VARIOUS AUTHENTICATING OR SECURITY APPLICATIONS, PARTICULARLY AN OPTICALLY VARIABLE SECURITY DEVICE UTILI SING LIQUID CRYSTAL MATERIALS. THE SECURITY DEVICE COMPRISES A LIQUID CRYSTAL LAYER (11), AN AT LEAST PARTIALLY ABSORBING LAYER (12) ADJACENT AT LEAST A PART OF ONE SIDE OF THE LIQUID CRYSTAL LAYER (11), AND AT LEAST ONE CUSTOMISING REGION (13) WHICH IS ADJACENT AT LEAST A PART OF AN OPPOSITE SIDE OF THE LIQUID CRYSTAL LAYER (11) TO THE ABSORBING LAYER (12) IN SELECTED REGIONS. THE AT LEAST ONE CUSTOMISING REGION (13) MODIFIES THE COLOUR SHIFTING PROPERTIES OF THE LIQUID CRYSTAL LAYER (11) SUCH THAT AT LEAST TWO CONTRASTING OPTICALLY VARIABLE REGIONS ARE PROVIDED BY THE REGIONS COVERED BY THE AT LEAST ONE CUSTOMISING REGION AND REGIONS NOT COVERED BY THE AT LEAST ONE CUSTOMISING REGION.