Desensitizable self-contained record material useful for security documents and the like
US4873219A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 15, 1988 |
| Grant date | Oct 10, 1989 |
| Priority date | — |
| Expiry date | Nov 15, 2008 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S428/913
- WIPO fieldTextile and paper machines
- WIPO sectorMechanical engineering
Abstract
An improved self-contained record material having tamper resistance through an indicator quality is disclosed. The self-contained record material of the invention is suitable for forming a visible mark with a focussed means of pressure application such as a stylus, needle, or pen and which mark can then later be in part fixed by unfocussed light. The self-contained record material comprises a substrate on which is coated two sets of microcapsules only one of which is made photosensitive to change in viscosity upon exposure to actinic radiation, and the first of which are conventional microcapsules. The color formers in each of the sets of microcapsules are selected to express a different observed color. Original markings, for example, could be black (combination of the orange and blue color formers). After exposure to actinic radiation desensitizing the blue color former containing capsules, subsequent markings are orange indicating the aspect of the subsequence in time.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.