Field activated security articles including polymer dispersed liquid crystals, and including micro-encapsulated field affected materials
US6259506A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 23, 1998 |
| Grant date | Jul 10, 2001 |
| Priority date | — |
| Expiry date | Jun 23, 2018 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S283/901
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
In a first aspect this invention provides a security article comprising an electrically actuated optical switch comprised of a liquid crystal material. In one embodiment the liquid crystal material is disposed in a layer of polymer dispersed liquid crystal material. In a second embodiment the liquid crystal material is micro-encapsulated with an orientable dye. In a second aspect this invention provides a document or currency that comprises a paper matrix that includes at least one security article, i.e. a security thread. In a third aspect this invention provides a device for verifying an authenticity of a document or currency of a type that includes at least one security article, i.e. at least one security thread. The at least one security thread includes the liquid crystal material having a visual characteristic that is switched between two states as a function of a presence or absence of an electric field between first and second electrodes. In one embodiment the device for verifying the authenticity of the document or the currency includes an external pump source for generating a stimulated emission the at least one security article disposed within the document or currency. In…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.