Optical effect layers showing a viewing angle dependent optical effect, processes and devices for their production, items carrying an optical effect layer, and uses thereof
US9849713B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 20, 2013 |
| Grant date | Dec 26, 2017 |
| Priority date | — |
| Expiry date | Dec 25, 2033 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/24273
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
The invention relates to the field of the protection of security documents such as for example banknotes and identity documents against counterfeit and illegal reproduction. In particular, the invention relates to optical effect layers (OEL) showing a viewing-angle dependent optical effect, devices and processes for producing said OEL and items carrying said OEL, as well as uses of said optical effect layers as an anti-counterfeit means on documents. The OEL comprises a plurality of non-spherical magnetic or magnetizable particles, which are dispersed in a coating composition comprising a binder material, the OEL comprising two or more loop-shaped areas, being nested around a common central area that is surrounded by the innermost loop-shaped area, wherein, in each of the loop-shaped areas, at least a part of the plurality of non-spherical magnetic or magnetizable particles are oriented such that, in a cross-section perpendicular to the OEL layer and extending from the center of the central area to the outer boundary of the outermost loop-shaped area, the longest axis of the particles in each of the cross-sectional areas of the looped-shaped areas follow a tangent of either a negat…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.