Magnetic marker having switching section for use in electronic article surveillance systems
First Claim
1. A marker adapted for use in an electronic article surveillance system said marker having a substantially sheet-like configuration and comprising a magnetic construction having at least one switching section and flux collectors proximate to each end of each switching section, wherein said construction comprises pieces of magnetic material in which the overall length and width respectively are not greater than 3.2 cm and(a) wherein each of said switching sections(i) is formed of a piece of low coercive force, high permeability material;
- (ii) has a minimum width at which the cross-sectional area is in the range of 0.003-0.03 mm2, and(iii) has a length normal to the minimum width not greater than twenty times that width and less than 2.0 cm, the terminal ends of said length being further defined by points at which the width parallel to said minimum width is no longer less than five times the minimum width, and(b) wherein each of said flux collectors(i) is formed of co-planar sections of sheet-like material having a low coercive force and high permeability, and(ii) has a width not less than ten times the minimum width of any switching section.
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Accused Products
Abstract
A magnetic marker for use with electronic article surveillance systems in which a very high order harmonic response is obtained with postage-stamp sized pieces of high permeability material shaped to have a narrow switching section within which flux is concentrated by larger sections on each end of the switching section, the concentrated flux being sufficient to result in a high harmonic response.
95 Citations
28 Claims
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1. A marker adapted for use in an electronic article surveillance system said marker having a substantially sheet-like configuration and comprising a magnetic construction having at least one switching section and flux collectors proximate to each end of each switching section, wherein said construction comprises pieces of magnetic material in which the overall length and width respectively are not greater than 3.2 cm and
(a) wherein each of said switching sections (i) is formed of a piece of low coercive force, high permeability material; -
(ii) has a minimum width at which the cross-sectional area is in the range of 0.003-0.03 mm2, and (iii) has a length normal to the minimum width not greater than twenty times that width and less than 2.0 cm, the terminal ends of said length being further defined by points at which the width parallel to said minimum width is no longer less than five times the minimum width, and (b) wherein each of said flux collectors (i) is formed of co-planar sections of sheet-like material having a low coercive force and high permeability, and (ii) has a width not less than ten times the minimum width of any switching section. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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- 10. A compact, two directionally responsive marker adapted for use in an electronic article surveillance system, said marker comprising at least two switching sections formed of at least one piece of low coerciye force, high permeability magnetic material, each switching section having a minimum width at which the cross-sectional area is in the range of 0.003 to 0.03 mm2 and a length extending normal to the width, wherein the length of each section extends in substantially different directions, and each of the switching sections has flux collectors of low coercive force, high permeability material proximate each end thereof.
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19. A method of making a magnetically responsive marker adapted for use in an electronic article surveillance system, said method comprising the steps of:
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(a) providing at least one switching section for said marker of at least one piece of low coercive force, high permeability material, each said switching section having a minimum width at which the cross-sectional area is in the range of 0.003 to 0.03 mm2 and having a length normal to the minimum width not greater than twenty times that width and less than 2.0 cm, the terminal ends of the length being further defined by points at which the width parallel to said minimum width is no longer less than five times the minimum width, and (b) providing flux collectors proximate to each end of each switching section of co-planar sections of sheet-like material having a low coercive force and high permeability, each said flux collector having a maximum width not less than ten times the minimum width of any switching section, wherein overall magnetic construction has a length and width not greater than 3.2 cm respectively. - View Dependent Claims (20, 21, 22, 23, 24, 25, 26, 27, 28)
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Specification