Diffractive security element
US7144617B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | May 31, 2002 |
| Grant date | Dec 5, 2006 |
| Priority date | — |
| Expiry date | Feb 22, 2023 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31678
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A security element (2) comprising a reflective, optically variable surface pattern (3) which is embedded in a layer composite of plastic material and which can be visually recognized from predetermined observation directions is formed from a mosaic of optically active surface elements (13). In the mosaic of the surface pattern (3) at least two of the mosaic surfaces (11; 12) of the surface pattern (3) are arranged substantially adjacent and have microscopically fine light-diffractive relief structures (4). The spatial frequencies of the relief structures in the mosaic surfaces (11; 12) are of values from predetermined spatial frequency ranges in such a way that, in the case of illumination beams which are incident obliquely relative to a normal onto the plane of the layer composite, the relief structures of the mosaic surfaces (11; 12) deflect visible monochromatic light parallel to the normal (32). The relief structures of the mosaic surfaces (11; 12) differ only in respect of spatial frequency, the difference in the spatial frequencies in the adjacent mosaic surfaces (11; 12) being at most 40 lines/mm.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.