Printed document having a value and comprising a luminescent authenticity feature based on a host lattice

US6344261B1 · kind B1 · utility

Assignee

• GIESECKE & DEVRIENT GMBH · DE

Inventors

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

Key dates

• Filing date: Dec 6, 1999
• Grant date: Feb 5, 2002
• Expiry date: Dec 6, 2019

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31993
• WIPO field: Basic materials chemistry
• WIPO sector: Chemistry

Abstract

The invention concerns a printed valuable document with at least one authentication feature in the form of a luminescent substance based on a host lattice doped with at least one rare earth metal. The host lattice largely absorbs in the entire visible region of the spectrum, is excitable in large parts of the visible region of the spectrum and at least partially transparent in at least the wavelength range between 0.8 &mgr;m and 1.1 &mgr;m. In addition, the host lattice contains chromium as an absorptive substance in such a concentration that amplification of the emission by the luminescent substance takes place. The rare earth metal emits in the wavelength region between 0.8 &mgr;m and 1.1 &mgr;m.