公开(公告)号：US06257488B1

公开(公告)日：2001-07-10

申请号：US09308819

申请日：1999-07-02

申请人： Paul Robertson ,  John Fisher ,  Jon Burrell

发明人： Paul Robertson ,  John Fisher ,  Jon Burrell

IPC分类号： G06K708

CPC分类号： G07F7/086 ,  G06K7/084 ,  G07D7/04

摘要： Apparatus for detecting the presence of magnetic elongated particles in a substrate, the base material of the substrate having magnetic properties substantially differing from the corresponding magnetic properties of the elongated particles. The elongated particles have such a long and thin form that their demagnetization factor N is smaller than {fraction (1/250)}, they have a diameter smaller than 30 micrometer, and they a magnetic saturation field greater than 100 A/m. Apparatus includes an emitter which emits an electromagnetic source signal of one or more particular base frequencies to the substrate (e.g., so that any magnetic elongated particles present go into a non-linear part of a B-H curve for at least part of cycle of the source signal). Apparatus also includes a detector that detects an electromagnetic detection signal emanating from the substrate for examining the detection signal for the presence of particular higher harmonics of the base frequencies or of any linear combination of the base frequencies or of the harmonics, particular higher harmonics being indicative of the presence of the magnetic elongated particles.

摘要翻译： 用于检测衬底中磁性细长颗粒的存在的装置，该衬底的基底材料具有与细长颗粒的相应磁性能基本上不同的磁性能。 细长的颗粒具有这样的长而薄的形式，使其退磁系数N小于{分数（1/250）}，它们具有小于30微米的直径，并且它们的磁饱和场大于100A / m。 设备包括发射器，其向衬底发射一个或多个特定基本频率的电磁源信号（例如，使得存在的任何磁性细长颗粒进入BH曲线的非线性部分，用于源的至少一部分周期 信号）。 装置还包括检测器，其检测从衬底发出的电磁检测信号，以检查检测信号是否存在基频的特定高次谐波或基频或谐波的任何线性组合，特定高次谐波表示 磁性细长颗粒的存在。

公开(公告)号：US06598793B1

公开(公告)日：2003-07-29

申请号：US09308566

申请日：1999-06-30

申请人： John Fisher ,  Paul Robertson ,  Jon Burrell ,  David Cross

发明人： John Fisher ,  Paul Robertson ,  Jon Burrell ,  David Cross

IPC分类号： G06K708

CPC分类号： G07F7/086 ,  G06K7/084 ,  G07D7/04

摘要： A method for checking the authenticity of a security article of the type containing magnetic particles having a magnetic saturation field Hs being greater than 100 A/m. The method includes the following steps: (a) generating an alternating field of one or more fundamental frequencies; (b) subjecting an article to be detected to the field; (c) detecting a detection signal emanating from the article to be detected; and (d) examining the detection signal for the presence of any particular higher harmonics of the fundamental frequencies or of any linear combination of the fundamental frequencies and of the harmonics, the particular harmonics or the linear combination being indicative of the presence of the magnetic particles. The method is applied at point of transaction locations, where the article to be detected is brought into close proximity with a sensor.

摘要翻译： 一种用于检查包含磁饱和磁场Hs大于100A / m的磁性颗粒的类型的安全物品的真实性的方法。 该方法包括以下步骤：（a）产生一个或多个基本频率的交变场; （b）将物品检测到田地; （c）检测从待检测物品发出的检测信号; 和（d）检查检测信号是否存在基频的任何特定较高次谐波或基频和谐波的任何线性组合，特定谐波或线性组合表示磁性颗粒的存在 。 该方法应用于交易位置处，其中要检测的物品与传感器紧密接近。