SECURITY DEVICE FOR SECURITY DOCUMENT

摘要

A security device for verifying an authenticity of a security document comprises an at least partially transparent substrate with a first surface and a second surface. A first pattern is arranged on the first surface. This first pattern is derivable using a first seed pattern. A second pattern is arranged on said second surface. This second pattern is derivable using the first seed pattern and using a second seed pattern. Transmittances and reflectivities of the first and second patterns are selected such that in a reflection viewing mode, only the first seed pattern is visible. In a transmission viewing mode, however, only the second seed pattern is visible.