Patents Assigned to MIDS Magnetische Informations-und Daten-Systeme GmbH
  • Patent number: 4694148
    Abstract: In an access card having coded material which comprises a plurality of markings which under infrared radiation appear on an infrared receiver, it is provided in accordance with the invention in order to prevent counterfeiting that a continuous and transparent plastic foil or film blank (4), at least on a portion of its surface, has a layer (4a) that is not transparent to visible light and is transparent to infrared light; together with a substrate (5), the blank embodies a laminate which on its inside carries a photosensitive layer (7) covered by a layer that is transparent to infrared light. The markings (21-23) appear as a negative or positive on the photosensitive layer (7) as the result of exposure of the plastic foil or film blank (4) to light.
    Type: Grant
    Filed: July 5, 1985
    Date of Patent: September 15, 1987
    Assignee: MIDS Magnetische Informations-und Daten-Systeme GmbH
    Inventors: Erwin Diekemper, Dieter Kastrup