Patent · US Expired

Security document voiding system

US6186404A · kind A · utility

135Cited by
21References
16Claims
0Family size

Assignee

Inventors

Key dates

Filing dateJun 2, 1998
Grant dateFeb 13, 2001
Priority date
Expiry dateJun 2, 2018

Classification

  • Technology area (CPC A)Human Necessities
  • CPC primaryA63F2250/287
  • WIPO fieldFurniture, games
  • WIPO sectorOther fields

Abstract

The present invention is a system for voiding a security document. The system voids a security document by supplying heat to a localized area of a specially configured security document. According to the invention, conductive material is formed on a document so that at least one relatively higher resistance section is formed on the document. When a voltage is supplied to the document, a relatively high amount of heat is supplied to the document about the area of the relatively higher resistance section. Heat-sensitive material may be formed about the location of the relatively higher resistance section such that the heat sensitive material becomes visible or changes color when a voltage is supplied to the document.

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