Abstract:
A magnetostrictive element for use in a magneto-mechanical marker has a resonant frequency characteristic that is at a minimum at a bias field level corresponding to the operating point of the magnetomechanical marker. The magnetostrictive element has a magnetomechanical coupling factor k in the range 0.28 to 0.4 at the operating point. The magnetostrictive element is formed by applying cross-field annealing to an iron-rich (Fe) amorphous metal alloy (100) ribbon (45 to 82 percent iron) which includes a total of from 2 to 17 percent of one or more of Mn, Mo, Nb, Cr, Hf, Zr, Ta, V. Cobalt (Co), nickel (Ni), boron, silicon and/or carbon may also be included. The metal alloy (100) may include one early transition element selected from the group consisting of Zr, Hf and Ta, and also a second early transition element selected from the group consisting of Mn, Mo, Nb, Cr, and V.
Abstract:
PROBLEM TO BE SOLVED: To provide a method and apparatus for an EAS system which utilizes a usable RF spectrum and a frequency-division marker. SOLUTION: The marker is provided with a first resonant circuit 402 with a first flattened coil 406 having a pair of terminals and a capacitor C1 connected to the pair of terminals and which generates a first resonant signal in response to an inquiry signal and a second resonant circuit 402 having a pair of terminals, a second flattened coil 408 a part of which is overlapped with a part of the first flattened coil and a non-linear capacitor D1 connected to the pair of terminals, which receives the first resonant signal and generates a second resonant signal having a second resonant frequency. COPYRIGHT: (C)2005,JPO&NCIPI
Abstract:
A self-biasing magnetostrictive element for use in a magnetomechanical EAS marker is a strip of amorphous alloy with crystalline particles of semi-hard or hard magnetic material distributed throughout the bulk of the amorphous alloy strip. The crystalline particles are magnetized to bias the amorphous alloy strip to resonate in response to an interrogation singal. The crystalline particles are formed by heat-treating the amorphous alloy strip at a temperature above the Curie temperature of the amorphous alloy in the presence of a longitudinal magnetic field. The alloy strip is then cross-field annealed at a temperature below the Curie temperature of the amorphous alloy to form a transverse anisotropy in the amorphous bulk of the alloy strip. A preferred alloy composition includes iron, cobalt, niobium, copper, boron and silicon.
Abstract:
The invention may include a novel composition for and/or processing of an active element for an EAS marker that achieves the same or better performance of existing materials while solving the problem of higher cost. It may include a magnetomechanical active element formed by planar strip of amorphous magnetostrictive alloy having a composition Fe a Ni b
Abstract:
A flat magnetomechanical electronic article surveillance marker is provided having a magnetostrictive resonator and a pair of bias magnets disposed on opposite sides and adjacent the resonator to bias the resonator with a magnetic field of a preselected field strength. The pair of bias magnets and the resonator are maintained substantially parallel and coplanar with each other to form a thin, flat EAS marker. During assembly of the marker, the bias magnets can be laterally adjustable to fine-tune the resonant frequency of the marker, and to compensate for material variability. Alternately, during assembly of the marker, the bias magnets can be adjustable in length to fine-tune the resonant frequency of the marker, and to compensate for material variability.
Abstract:
An electronic article surveillance and identification tag (1) and system is provided. The tag couples energy from a radiated energy source, which comprises first and second radiated signals. A mixing member (4) in the tag mixes the first and second signals to produce a sideband of the first signal, which is re-radiated by the tag. The mixing member is activated by a controller (6) that switches the mixing member into and out of the circuit according to a code stored within the controller that is associated with an article to be identified. As the mixing member is activated and deactivated, the sideband is radiated in a sequential manner according to the stored code. A receiver detects the sideband, and a decoder recovers the stored code according to the sequence of received sideband emissions from the tag.
Abstract:
A magnetostrictive element for use in an magnetomechanical marker has a resonant frequency characteristic that is at a minimum at a bias field level corresponding to the operation point of the magnetomechancial marker. The magnetostrictive element has a magnetomechanical coupling factor k in the range 0.28 to 0.4 at the operating point (26). The magnetostrictive element is formed by applying current-annealing to an iron-nickel-cobalt based amorphous metal ribbon, or by cross-field annealing an iron-nickel-cobalt alloy that includes a few percent chromium and/or niobium.
Abstract:
A bias element (10) for use in a magnetomechanical EAS marker is magnetized to saturation (14). Then the magnetic charge in the bias element is redistributed (16) by applying to the bias element a magnetic field having an AC ringdown characteristic. The redistribution of magnetic charge improves the stability of the bias element, so that the marker incorporating the bias element is less likely to have its resonant frequency shifted by exposure to a stray magnetic field.
Abstract:
An EAS marker has a paintable or printable bias magnet material (56), which is either directly painted onto the EAS marker (55,65) or first placed onto a substrate material (58), which is then placed into the EAS marker. The material includes a magnetic powder mixed with resin and solvent. This "bias paint" is then applied onto the EAS marker. The magnetic powder, resin, and solvent provide a very dense layer after drying, which has a magnetic material density that is usually lower than a rolled product, but is higher than that of the injection-molded magnet material. Printing the bias magnet allows nondeactivatable magnetomechanical EAS markers to be made using web-based mass production methods.
Abstract:
A magnetomechanical EAS marker (20) is formed of a housing (22, 24), a magnetostrictive active element (12) in the housing and a bias element (not separately shown) fixedly mounted on the housing. A central portion of the active element is secured to the housing to keep the active element from shifting in a longitudinal direction relative to the bias element and to keep ends of the active element spaced from the housing. The active element remains free to mechanically resonate in response to an EAS interrogation signal. The stable positioning of the active element prevents variations in the bias magnetic field due to shifting relative to the bias element, while keeping ends of the active element free from frictional damping due to mechanical loading from contact with the housing.