Security paper with authenticity features in the form of luminescing substances

US4451530A · kind A · utility

Assignee

• GAO Gesellschaft für Automation und organisation mbH · DE

Inventors

• Wittich Kaule · Grafing, DE
• Gerhard Schwenk · Puchheim, DE
• Gerhard Stenzel · Germering, DE

Key dates

• Filing date: Oct 23, 1981
• Grant date: May 29, 1984
• Expiry date: Oct 23, 2001

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31996
• WIPO field: Control
• WIPO sector: Instruments

Abstract

Security papers with luminescing authenticity features worked into them or printed on them. The authenticity features used consist of a luminophore and one or more absorbing materials by which the emission and/or the excitation spectrum of the luminophore is changed in detectable fashion. The dyestuff can be present as an admixture to the luminophore, as a coating of a luminophore layer or as a coating on luminophore powder grains. For checking the authenticity of documents the emission spectrum of the luminophore is not used but the change generated by the technology used in the emission or excitation spectra.