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:
Feb. 17, 1998
Filed:
Jun. 24, 1994
Louis H Liang, Los Altos, CA (US);
Angstrom Technologies, Inc., Florence, KY (US);
Abstract
An authentication system combines a source of ultraviolet light (and optionally a scanning mechanism) with apparatus for capturing and recognizing either graphic images or characters or both, where the graphic images and/or characters have been previously made with fluorescent substances that may be invisible under ordinary visible light, but are rendered detectable by the ultraviolet light. As in conventional optical character recognition (OCR), the characters may be conventional alphanumeric characters readable by human readers once they are made visible. The authentication system has a housing enclosing its optical path, a source of UV light, a detector for detecting graphic images or characters, conversion of the detector signal to digital form, a memory storing predetermined indicia, recognition logic, and indicating means. The system may also include a scanning mechanism and optical filters to select predetermined wavelengths of fluorescent light. The detector may be capable of detecting both fluorescent images and normal visible images, and the authentication system may incorporate switching mechanisms to allow multiplexed acquisition of fluorescent and normally visible images. The authentication system can operate in conjunction with a process for marking articles with indicia selected from a predetermined set of graphic images and characters readable by optical character recognition and/or by image comparison. That process can include printing fluorescent graphic images or characters in registration with (or with predetermined offset from) visible images or characters or indicia printed with substances fluorescent at different wavelengths. The recognition logic of the authentication system can include comparison of fluorescent and visible images or two different fluorescent images with each other. Pairs of indicia to be recognized and/or compared may be arranged to constitute a stereogram or other arrangement for first-order authentication by a human observer.