Security paper with authenticity features

US4446204A · 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 1, 1984
• Expiry date: Oct 23, 2001

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10T428/31703
• WIPO field: Control
• WIPO sector: Instruments

Abstract

Security paper with authenticity characteristics embodied therein or printed thereon which are both ferrimagnetic and also only slightly absorbed in the infrared spectral region. The presence of both properties at the same position on the security paper is tested, wherein both tests can preferably be carried out simultaneously. Materials which show this rare combination of properties are some ferrites, ferrimagnetic garnet compounds and the so-called green ferromagnetic compounds.