Optical data element including a diffraction zone with a multiplicity of diffraction gratings
US5811775A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 5, 1995 |
| Grant date | Sep 22, 1998 |
| Priority date | — |
| Expiry date | Dec 5, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K2019/0629
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An optical data element includes a plurality of diffraction zones wherein each zone contains a multiplicity of diffraction gratings. These zones may be illuminated and the resultant one or more diffracted beams detected to provide a signature for the element consisting of a series of discrete signature signals each generated by the plurality of zones and each including portions or relatively different intensities. At least one of the diffraction zones has a segment thereof modified whereby to discernibly alter at least one of the discrete signature signals of the signature and to thereby form a data segment of the optical data element.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.