Patent ID: 6373388
Filing Date: 2002-04-16
Classification: G01V,G06Q,G08B,Y10T

Abstract:
A method of identifying individual articles or classes of articles by means of data characteristic of the articles, which method is characterized by applying to each article a magnetic tag or marker carrying a predetermined arrangement of magnetic elements unique to that article or to that article and others sharing the same characteristic, said magnetic tag or marker being susceptible to interrogation by the steps of: (1) applying a magnetic field to an interrogation zone where the magnetic element(s) is or are located, or is or are expected to be located, such that there exists within said interrogation zone a magnetic field comprising a first region at which the component of the magnetic field resolved in a first direction is zero, and being characterized in that within regions contiguous with said first region the component of the magnetic field resolved in said first direction is sufficient to saturate the, or a part of the element(s); (2) causing relative movement between said magnetic field and said magnetic element(s); and (3) detecting the magnetic response of the magnetic element(s) during said relative movement to generate a response indicative of the magnetic properties of the tag or marker and hence indicative of the price and/or the nature of the article carrying the magnetic tag or marker.