Electronic identification system

摘要

An electronic identification system for reading a pre-defined identifier code. A preferred application provides a credit card sized "identifier" which includes an array of electrical inductors, some of which are electrically connected in a selected pattern to define the identifier code. The identifier may be positioned closely proximate to a substantially identical inductor array included in a "reader" so that each identifier inductor is centered over a corresponding reader inductor. An alternating current is applied to each reader inductor in turn to induce an electromagnetic field in the region surrounding the driven inductor. The electromagnetic field so produced induces a voltage across the identifier inductor centered over the driven reader inductor. If that identifier inductor is electrically connected to another identifier inductor(s) a current will flow in the other inductor(s) and a second electromagnetic field will be generated in the region(s) surrounding the connected inductor(s). The second electromagnetic field induces a voltage across reader inductor(s) centered under the connected inductor(s). Each reader inductor is separately sensed. If a current output signal is sensed at reader inductor(s) other than the driven inductor, it may be assumed that identifier inductor(s) corresponding to the driven inductor and to the reader inductor(s) at which an output signal is sensed have been electrically connected. A master control device may thus determine the identifier code by noting those identifier inductors which are electrically connected.