Improvements in security documents and substrates therefor

摘要

A substrate for producing security documents such as banknotes, cheques and passports which are required to provide a high degree of security against imitation comprises a first layer (16) of biaxially oriented polymeric film laminated together with a second layer (15) of biaxially oriented polymeric film with a metallic layer (18) between, and a third layer (14) of biaxially oriented polymeric film laminated to the second layer with a partially metallised metallic layer (19) therebetween, the metal in each metallic layer being the same or visually similar. At least one metallic layer may provide an electrically conductive path along the width or length of the substrate. A magnetic material may be present between two metallic layers. A layer of polarising material or a dichroic coating may be present on the surfaces of the substrate.