Security devices
US4186943A · kind A · utility
75Cited by
3References
13Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Sep 23, 1977 |
| Grant date | Feb 5, 1980 |
| Priority date | — |
| Expiry date | Sep 23, 1997 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S283/904
- WIPO fieldControl
- WIPO sectorInstruments
Abstract
A sheet element, such as a banknote or other document of intrinsic value, incorporating an optical authenticating device comprising a thin film element, preferably in the form of a strip, or thread disposed within the thickness of the sheet element and having known characteristics of spectral reflectance and transmittance, and wherein in the region of a least part of the thin film element the sheet element is formed with a pair of superposed windows between which the thin film element extends so as to be visible through each window.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.