Method and device for checking authenticity of a security element
AssigneeGiesecke & Devrient GmbH
InventorsKarlheinz Mayer, Reinhard Plaschka, Georg Depta
Life of this patent
Estimating the term…
Abstract
The invention relates to a method, in which from two images of a security element, which are recorded with right-handed and left-handed circularly polarizing filters, a differential image is produced, on the basis of which the authenticity of the security element is tested, and an apparatus for carrying out the method.
Claims32
Method for authenticity testing a security element on the basis of liquid-crystalline materials, the security element having at least one marking with circularly polarizing material, comprising the steps
- filtering the light impinging on the security element or the light reflected by it by means of a first circular polarizer for a first polarization direction and recording a first image of the security element,
- filtering the light impinging on the security element or the light reflected by it by means of a second circular polarizer for a second polarization direction and recording a second image of the security element,
- determining a differential image from the first and second image,
- deriving a statement about the authenticity of the security element on the basis of the differential image.
Apparatus for authenticity testing a security element on the basis of liquid-crystalline materials, the security element having at least one marking with circularly polarizing material and the apparatus comprising the following components
- at least one left-handed circular and one right-handed circular polarizer,
- at least one image recording apparatus for recording one or several image(s) of the security element,
- means for determining a differential image.
Dependencies are inferred from the claim text.