Patent · US Expired

Invisible, machine-detectable security marking, production of the security marking, and security system comprising this security marking

US7401817B2 · kind B2 · utility

5Cited by

20References

12Claims

0Family size

Assignee

SICPA HOLDING SA · CH

Inventors

Christoph Muller-Rees · Pullach, DE
Jurgen Kupfer · Berlin, DE
Horst Leigeber · Oberhaching, DE
Georg Schwalb · Birkenfeld, DE

Key dates

Filing date	Nov 19, 2002
Grant date	Jul 22, 2008
Priority date	—
Expiry date	Aug 21, 2025

Classification

Technology area (CPC G)Physics
CPC primaryG06K7/12
WIPO fieldComputer technology
WIPO sectorElectrical engineering

Abstract

The invention relates to a security marking whose level of proof against forgery is greater than that of known security markings, comprising liquid-crystalline material with chiral phase, wherein the security marking is imperceptible to the eye and the properties of the liquid-crystalline material with chiral phase can be detected with the aid of detection systems.

Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.