The invention relates to the field of the protection of security documents such as for example banknotes and identity documents against counterfeit and illegal reproduction. In particular, the invention relates to optical effect layers (OEL) showing a viewing-angle dependent optical effect, devices and processes for producing said OEL and items carrying said OEL, as well as uses of said optical effect layers as an anti-counterfeit means on documents. The OEL comprises a plurality of non-spherical magnetic or magnetizable particles, which are dispersed in a coating composition comprising a binder material, wherein in at least a loop-shaped area of the OEL at least a part of the plurality of non-spherical magnetic or magnetizable particles are oriented such that their longest axis is substantially parallel to the plane of the OEL, and wherein, in a cross-section perpendicular to the OEL and extending from the center of the central area, the longest axis of the oriented particles present in the loop-shaped area forming the impression of the loop-shaped body follow a tangent of either a negatively curved or a positively curved part of a hypothetical ellipse or circle.

Method and device for self-regulated flux transfer from a source of magnetic energy into one or more ferromagnetic work pieces, wherein a plurality of magnets, each having at least one N-S pole pair defining a magnetization axis, are disposed in a medium having a first relative permeability, the magnets being arranged in an array in which gaps of predetermined distance are maintained between neighboring magnets in the array and in which the magnetization axes of the magnets are oriented such that immediately neighboring magnets face one another with opposite polarities, such arrangement representing a magnetic tank circuit in which internal flux paths through the medium exist between neighboring magnets and magnetic flux access portals are defined between oppositely polarized pole pieces of such neighboring magnets, and wherein at least one working circuit is created which has a reluctance that is lower than that of the magnetic tank circuit by bringing one or more of the magnetic flux access portals into close vicinity to or contact with a surface of a ferromagnetic body having a second relative permeability that is higher than the first relative permeability, whereby a limit of effective flux transfer from the magnetic tank circuit into the working circuit will be reached when the work piece approaches magnetic saturation and the reluctance of the work circuit substantially equals the reluctance of the tank circuit.

A magnet apparatus for generating a high gradient and/or high strength magnetic field, comprises: two permanent magnets (2, 4) located side-by-side with oppositely oriented magnetic field polarities and end surfaces of opposite polarities next to one another, wherein the magnetic anisotropy of the magnets exceeds the magnetic induction of the material of the magnets; and a mask (6) or masks (6) on a first end of each of the adjacent permanent magnets (2, 4), the mask(s) 6 comprising a non-retentive material covering adjacent end surfaces of the two permanent magnets (2, 4) with a gap (8) along a joining line between the two permanent magnets (2, 4) to form a zone of high-gradient magnetic field above the joining line; wherein the mask(s) (6) are embedded within the magnets (2, 4) and/or have a varying thickness and wherein the mask(s) (6) each have a maximum thickness greater than a tenth of the thickness of the respective magnet (2, 4).

A circulator is provided, comprising, first second and third conductors forming three equally spaced junctions and a permanent magnet configured to apply a shaped bias magnetic field to a ferrite resonator in operable communication with the first, second, and third conductors. The permanent magnet comprises a substantially planar monolithic structure having defined thereon at least first and second substantially concentric regions having first and second respective magnetic field strength levels, wherein the second magnetic field strength level is lower than the first magnetic field strength level. The first and second magnetic field strength levels are configured to cooperate to shape an external bias magnetic field of the permanent magnet to counteract at least a portion of a demagnetizing effect resulting from of an overall shape of the ferrite resonator, to achieve a substantially uniform internal magnetic bias within at least a portion of the ferrite resonator.

A magnet array (400) includes multiple magnet (411-420) rings and a frame. The multiple magnet rings are positioned along a longitudinal axis and coaxially with the longitudinal axis, wherein at least two of the magnet rings include mixed-phase magnet rings (411, 413) that are phase-dissimilar. The multiple magnet rings are configured to jointly generate a magnetic field along a direction parallel to the longitudinal axis of at least a given level of uniformity inside a predefined inner volume (430). The frame is configured to fixedly hold the multiple magnet rings in place.

A magnet array (700) includes multiple magnet rings (711-720) and a frame. The multiple magnet rings are positioned along a longitudinal axis and coaxially with the longitudinal axis, wherein at least one (712, 713, 719) of the magnet rings possesses rotational symmetry and has both a finite component of magnetization along an azimuthal (θ) coordinate, and a finite magnetization in a longitudinal-radial plane. The multiple magnet rings configured to jointly generate a magnetic field along a direction parallel to the longitudinal axis. The frame is configured to fixedly hold the multiple magnet rings in place.

This invention relates to apparatus for creating a magnetic field to propel a magnetic device within a diverse media including biological matrices, tissues, organs, animals and humans. In one embodiment, a cylindrical dual Halbach array provides a uniform magnetic field with a settable field direction. Another embodiment provides support and orientation apparatus for a controlled-gradient conical magnet to achieve a full 4π steradian solid angle coverage around the specimen.

The present disclosure provides a stellarator magnet based on cubic permanent magnet blocks and an arrangement optimization method thereof. For the characteristic that a three-dimensional magnet coil of a stellarator is complex in structure, the present disclosure provides the stellarator magnet based on the cubic permanent magnet blocks with uniform magnetization, same magnetization and same size; the magnetization directions of the cubic permanent magnet blocks are defined in a limited number of fixed alternative directions; the magnetic field configuration of the stellarator is generated by dipole magnetic fields provided by the permanent magnet blocks and planar coils, so that the device complexity of the stellarator is reduced, and the difficulty and cost of the machining and installation of the magnet are reduced. The shape of the permanent magnet blocks can be replaced by other regular shapes, and the permanent magnet is still formed by the permanent magnet blocks with same shape, same size, uniform magnetization and same magnetization. For the magnet, the present disclosure provides a magnet arrangement optimization method of ‘local compensation’ and related optimization strategies of ‘threshold truncation,’ ‘global fine tuning,’ etc., for meeting different optimization requirements on accuracy of the magnetic fields, usage qualities of magnets, etc., and a magnetic field meeting designing requirements can be obtained.

An organizer for a plurality of metallic objects has a nonmetallic housing and a magnetic core. The nonmetallic housing has opposing top and bottom external surfaces. A ridge projects from a periphery of the top external surface. The magnetic core attracts metal towards the geometric center of the top external surface and towards the ridge at the periphery of the top external surface. In some implementations, portions of the magnetic field attract metal in the directions: (i) perpendicular to the geometric center of the top external surface; (ii) outward from the geometric center of the top external surface; and (iii) toward the ridge on the top external surface. Implementations have the magnetic core with a square cross section and north and south poles separated by a distance substantially less than the width of the substantially square cross section, and with its magnetic field in the shape of a torus.

A plural magnet arrangement of a matrix of rows and columns having an altered magnet field alignment of a plurality of the magnets in a matrix comprising rows and columns of magnets in such a manner that there are at times a co-existing combination of changing attractive and repelling magnetic field regions all throughout the coil winding volume, reducing the counter electromotive force (voltage) during electrically connecting a load to the coil winding terminals and extends the time duration of the output voltage waveform and this is accomplished wherein the rotational torque required to rotate the centre magnet through the coil of which it is centred within is reduced.