Permanent magnet assemblies for generating concave field lines and process for creating optical effect coating therewith (inverse rolling bar)
US9659696B2 · kind B2 · utility
1Cited by
10References
8Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 13, 2014 |
| Grant date | May 23, 2017 |
| Priority date | — |
| Expiry date | Jun 13, 2034 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01F7/0247
- WIPO fieldSurface technology, coating
- WIPO sectorChemistry
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 magnetic-field-generating devices which produce positively curved magnetic field lines in a concave fashion. The invention also relates to the use of these magnetic-field-generating devices for producing optical effect layers OEL which exhibit the optical impression of a positive rolling bar effect and to processes using these magnetic-field-generating devices, e.g. in the field of document security.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.