Information carriers with diffraction structures
US5886798A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 17, 1996 |
| Grant date | Mar 23, 1999 |
| Priority date | — |
| Expiry date | Jun 17, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03H2250/36
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An information carrier has at least one diffraction pattern which is formed from microscopically fine relief structures and which, upon being illuminated with coherent light, produces in two spatially separate directions, a first and a second image of an object. The images can be rendered visible on a screen or analysed by means of photodetectors. The two images have strong-light and/or weak-light picture elements and includes a symmetry insofar as a weak-light picture element of the second image can be associated with a strong-light picture element of the first image and vice-versa. Such information carriers are suitable as security elements for documents of all kinds such as, for example, banknotes, passes, identity cards, credit cards, etc., wherein at least a part of the security information is not visible under incoherent illumination conditions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.