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:
Sep. 18, 1990
Filed:
Aug. 01, 1988
Zvi Weinberger, Jerusalem, IL;
Prepaid Card Services, Inc., Pearl River, NY (US);
Abstract
A method of coding an optically-readable medium comprises: applying to the medium at least one coating of a heat-sensitive material to produce a specified combination of at least two optical changes as a function of time when heated to a predetermined temperature above ambient; heating the medium to the predetermined temperature; and sensing the optical changes undergone by the medium to determine whether the sensed changes match the specified combination. The method and apparatus are described particularly to an optically-readable medium wherein the heat-sensitive coating is in a plurality of windows formed in the medium, each window signifying a value element.