Orell Fussli Sicherheitsdruck Ag

Dieter Sauter

Sylvain Chosson

Martin Eichenberger

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. A second pattern is arranged on said second surface. The first and the second pattern each comprise a plurality of pixels with at least three different gray levels visible from a macroscopic perspective. The first and second pattern cover only gray levels in a range between 20% black and 80% black, in particular between 35% black and 65% black. The first pattern is inverted with respect to the second pattern.

Security device for security document

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.

A method for verifying the authenticity of a security document by means of a camera-equipped cellphone comprises steps of acquiring a transmission mode image and a reflection mode image of the security document. Transmitted light through a plurality of perforations in a substrate of the security document is evaluated by means of the cellphone. Then, a relative positioning of the perforations with respect to a printed security features is determined, and the security document is considered 'authentic' if the determined positions and the acquired images substantially correspond to pre-stored 'templates' for the security document. The perforations are structured such that they are not visible to the naked eye of a human observer which makes it harder to counterfeit the security document.

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Dietikon, Switzerland

Dieter Sauter