Optical reader with power isolation
US5233171A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Sep 13, 1990 |
| Grant date | Aug 3, 1993 |
| Priority date | — |
| Expiry date | Sep 13, 2010 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06K2207/1016
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
A optical reader for scanning optical marks from a substrate. The reader employs a novel optical geometry to eliminate undesirable specular reflections from entering the optical detection system. A stage area is provided for receiving the substrate, the stage having a window through which an incident beam of light passes at an oblique angle with respect to the window. A retrocollection system is used to return reflections from the substrate to the optical assembly. By directing the beam at an oblique angle with respect to the window, specular reflections are not collected in the retrocollection system and thus are not received by the optical detection system. The invention also utilizes a permanent magnet, direct current motor for controlling a scanning mirror, and further has a motor control circuit for preventing the introduction of electrical noise from the motor during the scan. A sensor may be provided to detect the presence of the card on the stage and provide "on demand" scanning.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.