Optical safety element and system for visualising hidden information
US7738173B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 16, 2004 |
| Grant date | Jun 15, 2010 |
| Priority date | — |
| Expiry date | Feb 10, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B5/1819
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
The invention concerns an optical security element and a system for visualising items of concealed information comprising such an optical security element. The optical security element has a substrate layer in which a relief structure defined by relief parameters, in particular relief shape, relief depth, spatial frequency and azimuth angle, is shaped in the surface region defined by an X-axis and a Y-axis, for producing an optically perceptible effect. One or more of the relief parameters defining the relief structure are varied in the surface region in accordance with a parameter variation function. The surface region is divided into one or more pattern regions and a background region. One or more of the relief parameters defining the relief structure are varied in the one or more pattern regions in accordance with a parameter variation function which is phase-displaced in relation to the parameter variation function of the background region. There is further provided a verification element which has a verification grating which is defined by a periodic transmission function and whose period corresponds to the period of the parameter variation function.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.