Method and device for identifying documents
US4211918A · kind A · utility
108Cited by
10References
15Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 6, 1978 |
| Grant date | Jul 8, 1980 |
| Priority date | — |
| Expiry date | Jun 6, 1998 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S283/904
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A method and device for identifying documents. A multiplicity of machine-readable markings which characteristically modify incident light by diffraction or refraction are applied to the documents, and selected markings are then cancelled out, the remaining markings representing coded information. The markings are of at least two different kinds causing different modification of incident light, and are arranged in a characteristic configuration on the documents. Information about said configuration is stored in an identification device to permit checking of the remaining markings.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.