Security document having a security thread embedded therein and methods for producing and testing the authenticity of the security document

US4756557A · kind A · utility

Assignee

• GAO Gesellschaft für Automation und organisation mbH · DE

Inventors

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

Key dates

• Filing date: Dec 23, 1985
• Grant date: Jul 12, 1988
• Expiry date: Dec 23, 2005

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y10S428/915
• WIPO field: Control
• WIPO sector: Instruments

Abstract

In order to increase the protection of security documents such as ban notes, etc., against forgery, security threads are embedded in the document which have at least two areas extending in the longitudinal direction of the thread and differing in their physical properties. The thread is preferably a coextruded multicomponent synthetic thread whose individual components contain additives such as dyes or fluorescent substances and/or particles having electrical or magnetic properties. The testing of the authenticity of the security thread is directed toward the presence of these additives and their mutual geometrical distribution in certain areas of the security thread.