Identification matter
US4500116A · kind A · utility
41Cited by
9References
7Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 14, 1980 |
| Grant date | Feb 19, 1985 |
| Priority date | — |
| Expiry date | Jul 14, 2000 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S428/916
- WIPO fieldOther consumer goods
- WIPO sectorOther fields
Abstract
A credential, such as a passport or an identification card, is provided, for example by impregnation or coating, with a phosphorescent composition which includes at least two phosphorescence activators which exhibit different emission characteristics both with respect to wavelength and lifetime so that, when the composition is irradiated, the initial afterglow changes color, for example from green to blue.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.