Token such as credit or identification card and an apparatus for testing the token or card

摘要

A security document such as a credit card or the like has material adapted to be optically scanned arranged along a line in the document. A modulating structure such as a document paper thickness is disposed within the document so as to be positioned between the line and an optically scanning, light sensing device. Accordingly, light emitting material in the line of the card upon being scanned will have the light thereof modulated so as to produce a reproducible authenticating variable when said line is scanned by the light sensing device.