Discrimination medium and discrimination method therefor
US7879415B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 2005 |
| Grant date | Feb 1, 2011 |
| Priority date | — |
| Expiry date | May 18, 2028 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03H2250/41
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A thermosensitive ink layer 102 is composed of a thermochromic material which changes from black to a transparent state and is formed on a substrate 101 made from a PET film by heating. A cholesteric liquid crystal layer 103 on which a hologram 105 of an appropriate form is formed on the cholesteric liquid crystal layer is mounted thereon. At ordinary temperature, the thermosensitive ink layer 102 exhibits a property of light absorption and a property of selective reflection and a color shifting of the cholesteric liquid crystal layer 103 are observed. The thermosensitive ink layer 102 becomes transparent by heating and the figure 104 on the substrate 101 is also visible. The determination of the authenticity thereof is performed by utilizing the change of view. Therefore, the anticounterfeiting effects are superior to those of the discrimination techniques using conventional techniques, and this enables articles to be distinguished easily and reliably.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.