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Identification card with a visible authenticity feature and a method of manufacturing said card

  • US 4,766,026 A
  • Filed: 10/15/1986
  • Issued: 08/23/1988
  • Est. Priority Date: 10/15/1985
  • Status: Expired due to Term
First Claim
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1. An identification card containing a plurality of synthetic layers in which information is provided by means of a laser beam, said information being visible in the form of changes in the optical properties of the synthetic material due to irreversible changes in the material caused by the laser beam, characterized in thatat least a first and a second layer have transparent areas which overlap,the first layer and the second layer have the property of changing visibly when exposed to the laser beam, this change being caused only as of certain intensity values and the particular intensity value required herefor being lower for the first layer than for the second layer,a first piece of information is provided in the first layer,a second piece of information is provided in the second layer, which is identical or is part of the first piece of information and is provided simultaneously with the first piece of information so that the second peice of information is present substantially congruent to the first piece of information in the recording direction, and in that the information in the first and second layers is provided by the beam in such a way as to be visible, either overlapping or singly, depending on the viewing angle, its appearance varying in accordance with the viewing angle.

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