Optical identification system and reader for reading optical gratings on a record medium
US4023010A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 8, 1975 |
| Grant date | May 10, 1977 |
| Priority date | — |
| Expiry date | Sep 8, 1995 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K7/10762
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An optical identification system including a reader for reading superimposed optical gratings on a record medium in which the reader has a grating plane and a radiant energy source for directing energy therefrom along an optical axis to the grating plane. Detectors are positioned in the reader to receive diffracted beams from the optical gratings on a record medium positioned at the grating plane. The reader also includes an optical imaging system having a concave lens for directing a zero order reflected beam which is displaced from the optical axis back to the grating plane to enable the resulting beams diffracted from the optical gratings to be received at the detectors whenever a record medium is displaced slightly from the grating plane.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.