The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Aug. 03, 1993
Filed:
Sep. 13, 1990
Dwight G Baldwin, Austin, TX (US);
Minnesota Mining and Manufacturing Company, St. Paul, MN (US);
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.