Authentication of documents and articles by moiré patterns
US7194105B2 · kind B2 · utility
Inventors
Key dates
| Filing date | Oct 16, 2002 |
| Grant date | Mar 20, 2007 |
| Priority date | — |
| Expiry date | Mar 15, 2025 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG07D7/207
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
The present invention relies on the moiré patterns generated when superposing a base layer made of base band patterns and a revealing line grating (revealing layer). The produced moiré patterns comprise an enlargement and a transformation of the individual patterns located within the base bands. Base bands and revealing line gratings may be rectilinear or curvilinear. When translating or rotating the revealing line grating on top of the base layer, the produced moiré patterns evolve smoothly, i.e. they may be smoothly shifted, sheared, and possibly be subject to further transformations. Base band patterns may incorporate any combination of shapes, intensities and colors, such as letter, digits, text, symbols, ornaments, logos, country emblems, etc. . . . . They therefore offer great possibilities for creating security documents and valuable articles taking advantage of the higher imaging capabilities of original imaging and printing systems, compared with the possibilities of the reproduction systems available to potential counterfeiters. Since the revealing line grating reflects a relatively high percentage of the incident light, the moiré patterns are easily apparent in reflectiv…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.