Metameric security devices using an active material
US10011140B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 3, 2011 |
| Grant date | Jul 3, 2018 |
| Priority date | — |
| Expiry date | May 26, 2035 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02F1/1506
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
An integrated security structure is provided employing an external source of energy to change the appearance of the structure rendering the structure more challenging to duplicate due to its complexity. The security structure includes a substrate forming part of a bank note, identification document, or other security device; an active device within the substrate changing color between at least two colors wherein a color of the substrate surrounding the active device matches one of the at least two colors to form a metameric device. At least one Interference Security Image Structure (ISIS) is configured to be metameric with a bleached state of the active device and is therefore invisible at normal incidence. Another ISIS is metameric with the colored state of the electrochromic device and consequently becomes invisible during coloration. When the whole device is tilted, both ISIS's change color while the rest of the device essentially remains the same.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.