Permanent magnet assemblies to generate concave field lines and process to create optical effect coating with these (reverse scroll bar)

摘要

The invention relates to the field of security document protection, such as, for example, banknotes and identity documents against counterfeiting and illegal reproduction. In particular, the invention relates to magnetic field generating devices which produce positively curved concave positively curved magnetic field lines. The invention also relates to the use of these magnetic field generating devices to produce optical optical effect layers which exhibit the optical impression of a positive scrollbar effect and to processes using these magnetic field generating devices, for example in the field of document security.