| 摘要 |
A method of producing a security document or device comprising a substrate (2) and an optically variable device in the form of a polarisation pattern, the method comprising the step of:
exposing an area of a surface (3,12,25,35,45) on one side of the substrate to a patterned laser beam bearing the pattern of the desired polarisation pattern which produces the polarisation pattern in said surface (3,12,25,35,45). In one embodiment, the patterned laser beam causes photo-polymerisation of said surface (3,12,25,35,45) to produce the polarisation pattern. In another embodiment, the patterned laser beam ablates selected portions of the surface (3,12,25,35,45) to form the polarisation pattern. |
