DE102007037293A1 - Radio frequency identification transponder's magnetic field screening apparatus for e.g. living area, has strips of screening material that has anisotropic permeability, where increased permeability is provided in current flow direction - Google Patents

Abstract

The apparatus has a flat antenna structure (8) with conductor tracks for conducting current in a direction of current flow in an area section (a). Strips (5) of a highly permeable screening material are applied to another area section (b) or a carrier (4) such that the strips are oriented with respect to one another in a preset manner, where the sections are arranged parallel to each other. The screening material has an anisotropic permeability, where an increased permeability is provided in the direction of current flow in a direction of the tracks of the former section of the structure. An independent claim is also included for a method for producing screening of a magnetic field of a radio frequency identification transponder.

Description

The The invention relates to a device for magnetic field shielding of a RFID transponders, and a method for producing a magnetic field shield an RFID transponder, as well as the use of a device for magnetic field shielding of an RFID transponder according to the generic terms of the claims 1, 2, 16, 17 and 31, respectively.

The Use of transponders, in particular of RFID transponders (radio-frequency identification transponders), has already prevailed in countless areas of life and work. Due to the nature of RFID transponders, below as well simply called transponders, via electromagnetic Fields contactless to record, process and process information again, they can be particularly advantageous Way to help reduce so-called media breaks, so gaps between the real physical world on the one hand and the digital world of information processing. In particular, their use involves automatic identification procedures in the foreground, which contribute to business or business technical processes, security relevant processes and also to improve general identification processes. typically, For example, such transponders are used for real-time identification Supply chains and in logistics processes of trading companies, the Pharmaceutical industry, the automotive industry and other manufacturing companies used and support the control and the process specific production and logistics processes. typically, transponders are mounted on packaging, pallets and containers, so that they are easily accessible and can be addressed quickly can.

The RFID technology is typically based on having serial numbers or codes on a microchip integrated in a transponder are stored, with the microchip both as electronic Data memory, as well as used for signal processing can. The serial numbers or the codes can be about about wireless communication are read out by means of magnetic fields. For this purpose, first a transponder antenna by resonance activated by an external magnetic field. The transponder is changing the received signal in a predetermined manner and then gives again a magnetic field, or changes the irradiated so that external resonators in a reader this Can detect field and thus the readout of information allow. Thereby the coupling of reader and transponder takes place comparable to the principle of loosely coupled transformer instead. The data transmission by means of magnetic field is typically carried out in the HF range. Modern RFID technology also allows several RFID transponder read simultaneously and fully automatically, without a direct line of sight between a reader and must pass the RFID transponder. Likewise, the RFID technology allows an application in adverse environments, such as using transponders in Objects are embedded, and thus of direct environmental influences not be directly influenced. Compared to bar code scanners for example, reading is also about a larger one Distance possible, with additional information stored and modified on an RFID transponder can and do so a very flexible and dynamic identification process enable.

Become However, such RFID transponder on metallically conductive surfaces used as underground, the functionality of this Devices sometimes drastically reduced, since it due to the used Magnetic fields for communication between transponder and reader for inducing eddy currents in the metallic material and sometimes also comes in the antenna structure and thereby the electrical excitation of the transponder antenna not with sufficient Energy can be done. By injecting a magnetic Alternating field namely in the metal surfaces induced such electrical eddy currents, which after the Lenz'schen In turn, usually induce a changing magnetic field, which counteracts the incident magnetic field. As a result, the resulting magnetic field becomes so strongly weakened on the metallic surface, that a sufficient energy supply of the transponder and a Data transfer will be impossible. additionally it comes through the metallic surface in the case of a direct contact with the electrically conductive transponder, or even at an approach to the same, to one significant detuning of the resonant frequency of the transponder, thereby either a renewed vote of the reader on the changed resonance frequency becomes necessary, or But other precautions must be taken to as usual fixed preset resonant frequencies communication between Reader and transponder.

In order to remedy such problems, among other things, mechanical spacers are used in conjunction with transponders on a metallic surface, which attach the transponder in a raised position over the metallic material. Although this ensures the functionality of the transponder, the structure can sometimes represent a significant limitation due to the resulting height of the transponder and spacer. Distances of a few centimeters are not uncommon for such spacers. In addition, the Manufacturing costs for such spacers far exceed the costs for the actual transponder and therefore let this technology for many processes in which high volumes are used, appear unattractive.

About that There are also thin plastic-bonded ferrite films for magnetic field shield use. The production of such However, ferrite foil places high demands on homogeneity of the composite material and therefore results in relatively high costs for the production. After lamination of this typically viscoplastic, brittle material made of ferrite and Plastic creates a stiff and barely bendable label with a Total height of typically at least one millimeter. Due to the stiffness, the device can only work on flat surfaces be attached. In addition, limit high production costs and the thickness of the entire device the application spectrum of this Magnetic field shielding on.

In the DE 100 17 142 A1 a self-adhesive data exchange label is described, which provides a transmitting and receiving device such as a transponder antenna, wherein also an erectable section is provided, by means of which the antenna can be brought into a position perpendicular to a metallic surface. With this positioning of the antenna, the data exchange on metallic surfaces is indeed improved, but a disadvantage results in turn a large average antenna distance from the metallic surface and a low mechanical stability of the data exchange label.

The EP 1 594 082 A1 describes an assembly and method for attaching a transponder element to an article, such as a metallic surface, with an expansion or shrink-wrapped label affixed between the surface and the transponder. Subsequently, the expansion or shrink film is activated by the supply of heat or UV light, wherein the distance between the transponder and surface can adjust advantageously, so as to result in the reduction of eddy currents on a metallic surface and an improved reading of the transponder is enabled , The device described, however, again characterized by a relatively large height, and also assumes that no mechanical forces act on the label. In addition, activation by heat or UV light may cause deterioration and damage to the object to which the label has been applied.

In the DE 101 49 126 A1 For example, a device for shielding a transponder and a method for producing a corresponding shield are described. The shielding is made possible using small, preferably 300 .mu.m.times.50 .mu.m.times.10 .mu.m, sized particles which are embedded in a liquid matrix and aligned in a magnetic constant field. The orientation is such that the particles run parallel to a magnetic field induced by the transponder. The shield is preferably applied by printing on a surface, wherein finally the curing of the printing structures takes place. The overall process is complex and results in a brittle and limited flexible shielding. Due to the printing process, the application is usually reduced to flat surfaces or makes a relatively complicated printing process necessary. The always parallel orientation of the particles to the induced transponder magnetic field lines requires complex magnetization units for complex antenna geometries to generate complex magnetic fields. In addition, highly accurate alignment during the lamination process to connect the transponder and shield is required to achieve parallelism between the magnetically-induced transponder field and the aligned particles, thereby significantly hindering mass production and, consequently, increasing the cost of a final product.

The present invention is based on the object, a device according to the DE 101 49 126 A1 To further develop this and to describe an even more efficient magnetic field shielding of materials that are easy to handle, which also has a structure that allows the easier alignment of magnetic field shielding and antenna structure. In addition, a method for producing such a magnetic field shield to be shown and a use of such a device will be described.

These The object is achieved by a device, a method and a use solved according to claims 1, 2, 16, 17 and 31, respectively.

In particular, the object is achieved by a device for magnetic field shielding of an RFID transponder with respect to a substrate comprising on a first surface portion at least one flat antenna structure, the conductor tracks for conducting current in a current flow direction and having an application-specific extent, wherein the device 2. surface portion or support comprises on which strip of high-permeability shielding material are applied in a predetermined manner aligned with each other, wherein the second surface portion is arranged parallel to the first surface portion, wherein the high-permeability shielding material has an anisotropic permeability, and wherein an increased permeability is provided in the current flow direction of substantial portions of the antenna structure.

Farther The object is achieved by a device for magnetic field shielding an RFID transponder solved, which on a 1st surface section comprises at least one flat antenna structure, the conductor tracks for conducting current in a current flow direction and an application specific one Expansion, wherein the device has a 2nd surface section or carrier comprises on which strip of a highly permeable Shielding material aligned in a predetermined manner to each other are applied, wherein the second surface portion to the 1. surface portion is arranged in parallel, wherein the Strip aligned in substantial sections parallel to each other and by clearances between longitudinal edges of the strips are spaced, wherein the longitudinal edges of the strips in the current flow direction, in particular in the direction of the conductor tracks essential portions of the antenna structure are provided.

Farther The object is achieved by a method for producing a magnetic field shield an RFID transponder solved, which on a 1st surface section comprises at least one flat antenna structure, the conductor tracks for conducting current in a current flow direction and an application specific one Has expansion, the method providing a 2. surface section or carrier comprises, on which strip of a high-permeability shielding material in a predetermined Are applied aligned with each other, wherein the second surface portion is arranged parallel to the 1st surface section, wherein the highly permeable shielding material with an anisotropic permeability is made, wherein the shielding material so relative is aligned with the antenna structure, that an increased permeability in the current flow direction, in particular in the direction of the conductor tracks essential sections of the antenna structure results.

Farther The object is achieved by a method for producing a magnetic field shield an RFID transponder solved, which on a 1st surface section comprises at least one flat antenna structure, the conductor tracks for conducting current in a current flow direction and an application specific one Has expansion, the method providing a 2. surface section or carrier comprises, on which strip of a high-permeability shielding material in a predetermined Are applied aligned with each other, wherein the second surface portion is arranged parallel to the 1st surface section, wherein the strips in substantial sections aligned parallel to each other and by clearances between longitudinal edges of the strips be spaced, with the longitudinal edges of the strips in the current flow direction, in particular in the direction of the interconnects essential Sections of the antenna structure are provided.

henceforth The object is achieved by a use of a device for magnetic field shielding an RFID transponder solved according to one of the claims 1 to 13, to reduce by eddy current losses caused Functional losses of the RFID transponder.

One essential point of the invention is that the magnetic field shield a high permeability shielding material in strips comprising have an anisotropic permeability, wherein an increased Permeability in the current flow direction of essential sections the antenna structure is provided. Due to the stripe shape of the Shielding material will not only eddy currents and the Consequently, induced magnetic fields suppressed, which in the Inserting the transponder in the magnetic field of a reader in the electrically conductive surface approximately a metallic object are generated, but also eddy currents, through the magnetic field of the reader in the strip self-induced. Another essential point exists in that the strips of high-permeability shielding material are aligned parallel to each other in essential sections and the longitudinal edges of the strips in the current flow direction, in particular in the direction of the tracks of essential sections the antenna structure are aligned. As a result, irradiated magnetic fields very advantageous distracted by the parallel structure of the strips, So also contribute to a reduction of eddy currents but they are also able to do so because of their geometric Shape and arrangement of the re-magnetization losses under irradiation to influence a magnetic alternating field.

Here, as in all other parts, parallelism is supposed to be one purely local, punctual parallelism can be understood. Consequently, it is also possible to speak of parallelism, if the strips have no straight side edges. In this one used sense can also parallelity, for example between wavy lines or circle segments occur when the Spacing between the side edges of two adjacent and spaced strips is constant, so the tangents on the side edge lines of two Strip an equal one in each next point Have slope.

It is described a magnetic field shield, which is intended to deflect the magnetic primary and possible secondary fields by means of a highly permeable material or attenuate, so that the weakening of the magnetic field on the surface of a metallically conductive material is reduced or even prevented. The orientation of the anisotropy of the permeability of the shielding material, or the orientation of the strips of the shielding material is such that the magnetic primary field is deflected such that the induced by the deflected magnetic primary field electric fields are perpendicular to essential portions of the antenna structure and thus the flow of current in the antenna structure, which takes place in a direction perpendicular thereto, can not affect. Likewise, the secondary magnetic field is partially deflected in such a way that no significant attenuation of the incident primary magnetic field can occur.

at A first embodiment of the invention is the strips essentially aligned parallel to each other and through open spaces spaced between longitudinal edges of the strips. Such Alignment of the strips allows geometric relative to create clear structures that facilitate alignment an adapted antenna structure allowed. Also allow the free spaces, high-permeability shielding material in comparison to save to a full-surface embodiment and still have a good shielding effect. This material saving is mainly in the production of high volumes the magnetic field shield economically extremely important. Far more decisive, however, is that the strips themselves for Suppression of electrical eddy currents, for example contribute from electrically conductive Ab schungsungsmaterialien.

As well The stripes can still be bundled Have effect with respect to the magnetic field, such as when the irradiated magnetic field of a reader is not vertical on the surface of the stripes, but at an angle. Above all, this effect also affects the Correction losses, which upon irradiation of a magnetic Alternating field are caused in the shielding material.

A Further advantageous embodiment of the device for Magnetic field shielding is characterized in that the shielding material a has electrical conductivity which is less than that of a substrate on which the magnetic field shield is applied can be. Consequently, in the shielding material compared to the ground, for example a metal surface, only in limited extent eddy currents occur and a corresponding Counter field are generated. The electrical conductivity of the shielding material can also be very low, with the Result that the eddy currents suppressed even further can be.

A further advantageous embodiment of the device for Magnetic field shielding is characterized in that the shielding material a having electrical conductivity lower than that Conductivity of the material of the antenna structure is. hereby is causing the eddy current losses in the shielding material themselves be kept low and no too large losses or lead to a weakening of the magnetic fields. In addition, possible detunings of the resonance frequency reduces the antenna structure of the transponder, which thereby can show that the strips as additional capacity the antenna structure of the transponder and a change cause the resonance frequency. Such frequency detuning are usually either by additional electronic Fixed components that are interconnected with the transponder, or by inserting another external, not interconnected Capacity, about in the carrier on which strip and transponders are arranged together. Such corrections to a small extent typically in each Case to be carried out to detune the transponder resonant frequency to fix the stripes. Although the shielding material of the strips can be electrically conductive, this feature closes the It does not mean that its conductivity is less than the conductivity of the material of the antenna structure is.

Farther it is possible that the shielding material iron, nickel, Cobalt, gadolinium, compounds of the substance group of garnets, such as Yttrium-aluminum compounds, alloys of these substances or samarium or amorphous metals. But they are also conceivable other ferromagnetic metals, substances and compounds as shielding material with similarly high permeability properties. These substances and compounds, or mixtures of these, which are characterized by a high absolute magnetic permeability can distinguish be used advantageously for an increased Permeability of the shielding material of the magnetization shield to ensure. Because these substances or compounds to handle industrially widespread materials They cost-effective production of the strips of the shielding material. Accordingly, the shielding material can be industrially made into a large size Scale produced materials are obtained in whose Make yourself a simple, easy to control process can serve.

In a preferred embodiment, the shielding material may comprise a soft-magnetic metal with low remagnetization losses, in particular a μ-metal. μ-metal are metal Lische materials, which are characterized both by a high permeability and by their soft magnetic properties. Such a soft magnetic material offers the advantages that the energy losses in the magnetic reversal in an alternating magnetic field compared to a normal metal or a hard magnetic metal are significantly reduced. Magnetization losses usually occur due to the work which a magnetic field has to perform in order to remagnetize the residual magnetization in a magnetized material, that is to say by the magnetization losses. By reducing the magnetization losses in the shielding material of the strips, for example, it is possible to use magnetic fields of lesser intensity for communication between the transponder and the reader, or to increase the range for effective communication between the transponder and the reader for the same intensity.

In a further preferred embodiment comprises Shielding material nano-crystalline structures. Nanocrystalline Structures can sometimes be characterized by very high absolute Distinguish permeabilities, where the permeability numbers sometimes well above 100,000. In addition, have crystalline Structures a preferred geometric direction, which identify an and align permeability.

In In an advantageous embodiment, the strips are flexible formed and have a thickness of less than 500 microns, preferably less than 100 .mu.m, in particular less than 50 μm, on. Through a flexible execution of Strips will also apply the strips on surfaces supports, which are not flat, but about a curvature exhibit. In addition, mechanical damage reduces the strip, or by their flexibility their mechanical strength can be increased, for example unforeseen force effects on the shielding material occur. By the intended thickness of the strips is granted that the transponder is not in a substantially raised position over the surface is arranged on which the transponder is attached together with the magnetic field shield. This can especially prove to be advantageous if the space limited for the devices for magnetic field shielding is.

A alternative embodiment may further be characterized that the strips in several, separated by insulator layers on top of each other are arranged. This makes it possible, the magnetic field shield even increase and even more effective magnetic field shielding to ensure by an additive shielding effect of multiple layers. The data transmission can thus be carried out more effectively, or over a longer range.

Farther For example, the carrier may be made of a substantially electrically non-conductive Material exist. The carrier thus has electrical insulating properties, which can be particularly advantageous for example, when the carrier is electrically conductive Antenna structure is in contact to short circuits or Suppress moods of the resonant frequency of the antenna structure, or to minimize.

Further it is possible for the wearer to be the inlay of a transponder is trained. This allows for safe and secure Storage of the transponder and also allows without Complications a fast and clear connection of the transponder with the inlay.

In a preferred embodiment is the carrier with the transponder attached to it in plastic, paper or Including film laminate, preferably at least one Insulator layer provided between the carrier and transponder is. The inclusion in plastic, paper or foil laminate allows the production of whole transponder magnetic field shielding units which for a good against external influences are protected, which also by appropriate shaping can be made to suit any spatial Requirements are adjusted.

The Device for magnetic field shielding can also be characterized that a surface portion, which of the Strip is taken on the 2nd surface section, at least as big as the first area section is and covers this. Such a device ensures a As complete as possible shielding of the transponder antenna structure and thus causes a surface best possible Magnetic shielding.

In a further advantageous embodiment, the device may be designed such that the transponder operates in the RF frequency range, in particular at 13.56 MHz. Such a transponder has the great advantage, in comparison to the similarly manufactured transponders operating in the LF range (low frequency range) at 135 kHz, that the antenna structure for inductive coupling with the reader requires far fewer antenna turns, thus resulting in significant space savings Has. By contrast, in transponders operating in the UHF frequency ranges of 868 MHz, 915 MHz and 2.45 GHz and 5.8 GHz, the coupling between the reader and the transponder does not take place via magnetic but via electromagnetic coupling. However, such UHF transponders are not universally applicable, since your permitted working frequencies differ strongly regionally. Products that could easily be identified, for example, in one country via an 868 MHz transponder, may not be identified in another country at 868 MHz because the allowed frequency ranges of the electromagnetic radiation used do not match the resonant frequency of the antenna structure of the transponder , However, if the transponder used is an RF transponder, then it can be read out universally and independently of its location since only energy in the form of magnetic waves is required for its readout and the designated frequency range is internationally permitted and standardized.

The Method for producing a magnetic field shield may be in a preferred embodiment characterized that the strips are aligned substantially parallel to one another and by clearances between longitudinal edges of the strips be spaced. Such alignment of the strips allows it is to create geometrically relatively clear structures, which one allow easier alignment of the antenna structure.

A furthermore advantageous embodiment of the method for producing a magnetic field shield is characterized from that the shielding material has an electrical conductivity which is lower than that of a substrate on which the magnetic field shield can be applied. Consequently, you can in the shielding material, for example in the form parallel strip is present, compared to the ground, for example a metal surface, only to a limited extent eddy currents occur and a corresponding opposing field are generated. The electric Conductivity of the shielding material may as well be low, with the result that the eddy currents are still can be further suppressed.

As well The stripes can still be bundled Have effect with respect to the magnetic field, such as when the irradiated magnetic field of a reader is not vertical on the surface of the strip invades, but in one Angle. Above all, this effect also affects the re-magnetization losses which, upon irradiation of an alternating magnetic field in caused the shielding material.

In an alternative embodiment of the method the strips by etching a full-surface shielding material produced. This also ensures that again the strips industrially in a short time with a well controllable process can be produced in high volumes. In addition, this method also allows compliance very accurate Specifications for the dimensions, or rendering of very fine structures, if used in conjunction with him a lithographic process which enables excellent optical resolution.

The full-surface shielding material can in another preferred embodiment of the carrier in a roll-to-roll process. Roll-to-roll Processes are common industrial processes, which in turn the production of large numbers of magnetic field shields allow. Suitable carrier substances are, for example organic foils or paper. The generation of the stripes takes place typically in a next process step, which such as lithographic or printing techniques, such as screen printing, stencil printing, Pad printing or transfer printing, used. This can be done in standard procedures the generation of arbitrary arrangements of strips executed which are in any direction to the full-surface Shielding material can be arranged. A printing process also offers even the advantage of short set-up times, so high flexibility for design changes with low tooling costs and the presence a broad infrastructure for roll-to-roll processing. Before production of the strips, the full-surface shielding material printed with a pattern that reflects the arrangement of the stripes. If these are already connected to the carrier is the carrier provided with a protective varnish. After hardening the protective varnish, which, for example, by heat convection, electromagnetic radiation or by moisture can, passes through the printed full-surface shielding material various etching and cleaning baths, in which the actual production of the strips takes place. This would be also conceivable that the protective lacquer used later than Lamination adhesive and / or electrical insulator can serve.

alternative For this, the procedure may include that the strips through a machining, mechanical shaping process are produced. in this connection would be, for example, cutting or milling processes lead, which allow a material removal and Strip as well in the industrially necessary quantities can produce. In addition, by machining processes practically all materials workable.

Still alternatively, the strips are made by a non-chip mechanical forming process. Rolling or stamping processes, which are mainly used for the processing of soft shielding materials, are to be expected for this purpose. By means of well controllable industrial rolling processes is also the thickness of the produced strips easily up to thicknesses of a few microns and even smaller thicknesses possible. This makes it possible to manufacture mechanically very thin layers of shielding materials, which consequently can be used extremely advantageously in the production of magnetic field shields of extremely small thicknesses with very low material costs.

moreover The strips can be removed by a wet-chemical method getting produced. Wet chemical processes have the advantage that with them layers of extremely small thicknesses directly can be applied to a support and moreover, there may not be any special connection of carriers and strip is needed for a firm connection. Furthermore wet-chemical processes are relatively easy even with simple means to produce complex stripe structures. Moreover, you can They are also advantageous with further application steps for the production the stripes are combined. So it is conceivable, for example to carry out a wet-chemical method in a magnetic directional field, so as to produce the strips in one process step and an anisotropy of the permeability of the shielding material bring about.

When Another alternative is also conceivable that the stripes by physical or chemically depositing the shielding material on the support getting produced. Even such methods allow the direct connection of carrier and strip, as well as the Production of strips, very small thickness approximately from the gas phase out. Since it is about the deposition process CVD (Chemical Vapor Deposition) or PVD (Physical Vapor Deposition) by industrial is widely used in addition to a procedure guarantee high conformity of the generated deposits For example, you can strip easily with these methods produced inexpensively in large quantities become.

In A preferred embodiment of the method is the Anisotropy of the permeability of the high permeability material induced or amplified by means of a magnetic directional field. This method also allows mixtures of substances or particles with intrinsic anisotropy of permeability for production to use the strip, which is about initially suspended present, according to their magnetic permeability be aligned and then aligned in Position can be fixed in position. This is about the Use of resins conceivable in which suspended ferrite particles are and after alignment by means of a magnetic directional field by heat or light of certain wavelength ranges be cured. A production would be conceivable the strip by printing techniques.

In an alternative embodiment, the fixation takes place the strip on the support by means of an adhesive or a paint. Such fixatives are cheap and easy available, so allow a relatively inexpensive In addition, manufacturing process, which is still easy to control is.

Further It is also possible that the carrier after fixing the strip on it is connected to the transponder. This procedure allows for example, to produce a magnetic field shield separately, thus partially independent of the antenna structures of the Transponders and distribute as a self-contained product.

alternative this is also possible that the carrier before the Fixing the strips on it is connected to the transponder. This method of production would be used approximately then if the unit is made of strips, carrier and transponders as a whole in a manufacturing process and to be distributed.

It is furthermore conceivable that the connection of transponder and device for magnetic field shielding by means of folding, laminating or a Encapsulation process takes place. These procedures in turn allow to apply relatively simple standard procedures, such as those for The production of check cards are known to be a unit of transponder and magnetic field shielding, which in protected Form is present.

Further Embodiments of the invention will become apparent from the dependent claims.

following the invention will be described by means of exemplary embodiments, which are explained in more detail with reference to the figure. Hereby show:

1 a first embodiment of the invention in supervision,

2 the first embodiment of the invention in a plan view with a transversely mounted transponder of rectangular geometry,

3 a section along the line III-III off 2 .

4 a second embodiment of the invention in top view with a superficially mounted transponder, which from the 2 is comparable,

5 a third embodiment of the invention in top view with a superficially mounted transponder, which from 2 and 4 is comparable,

6 a fourth embodiment of the invention in top view with a superficially mounted transponder, which from 2 . 4 and 5 is comparable,

7 a fifth embodiment of the invention in top view with a superficially mounted transponder, which from 2 . 4 . 5 and 6 is comparable,

8th a sixth embodiment of the invention in plan view with a superficially mounted transponder, which from 2 . 4 . 5 . 6 and 7 is comparable,

9 a seventh embodiment of the invention in plan view with a superficially mounted transponder of round geometry;
In the following description, the same reference numerals are used for identical or identically acting parts.

1 shows a rectangular magnetic field shield 1 , whose longitudinal extent is greater than the transverse extent. The rectangular shape is made by the carrier 4 defines on which the stripes 5 are applied from the magnetic field shielding material. The Stripes 5 have even a rectangular shape such that their flat longitudinal extent is significantly greater than their transverse extent. In total there are six stripes 5 arranged parallel to each other. Between the strips 5 are each uniform free spaces 6 , The Stripes 5 are further arranged so that they are completely within the surface portion of the carrier 4 lie. Other possible cover layers over the strip 5 or insulating layers between the strips 5 and the carrier 4 are not shown here.

2 shows a magnetic field shield 1 , as already out 1 known, being on the magnetic field shield 1 a flat transponder 2 is arranged, consisting of an antenna structure 8th as well as a microchip 10 and an antenna bridge 11 consists. The antenna bridge 11 provides electrical contact between the end pieces of the antenna structure 8th ago. The planar transponder defines a first area section (a). The carrier itself defines a second area section (b). The tracks of the antenna structure 8th the transponder 2 are arranged in rectangular geometry, wherein the areal transverse dimension of the antenna structure 8th is smaller than its longitudinal extent. In an embodiment of the magnetic field shield according to the invention 1 with anisotropic permeability, the direction of increased permeability is parallel to the top-to-bottom longitudinal edges of the strips 5 and parallel to the visible surface. Alternatively, the direction of increased permeability may also be perpendicular to the longitudinal edges of the strips (FIG. 5 ), ie parallel to the left-to-right conductor tracks of the antenna structure ( 8th ). In this case, too, it is ensured that an increased permeability in the direction of the interconnects of essential sections of the antenna structure ( 8th ) is present. Which sections of the antenna structure ( 8th ) are considered to be essential, results primarily from the geometry of the antenna structure ( 8th ). In the present case of a rectangular antenna structure ( 8th ) are both the top-to-bottom traces and the left-to-right traces to the essential portions of the antenna structure ( 8th ).

The antenna structure 8th is with the microchip 10 connected such that after resonance excitation of the antenna structure 8th , whose end pieces via the antenna bridge 11 electrically connected, the microchip 10 can process an antenna signal. The antenna structure 8th is further formed as a coil, which allows an inductive coupling with an externally irradiated magnetic field. For this purpose, the antenna structure 8th arranged with a capacitance to a resonant circuit, the microchip 10 is tuned to the operating frequency of the resonant circuit and is powered by the excited resonant circuit with energy. The on the microchip 10 stored data can be transmitted and read, for example, by a damping modulation of the incident magnetic field. antenna structure 8th , Antenna bridge 11 and microchip 10 can be directly connected to the magnetic field shield, or via an insulating layer, which in 2 is not explicitly shown. Should a connection be provided without an insulating layer, then the shielding material of the strips 5 not be electrically conductive so as not to electrically short circuit the conductive antenna structure 8th manufacture. Alternatively to an insulating layer between the strips 5 and the antenna structure 8th One could also use an insulating layer, which only surrounds the antenna structure and thus makes an electrical contact to the outside impossible.

3 illustrates a cross section through the arrangement 2 along the line III-III with transponder 2 and magnetic field shielding 1 Similarly, in 3 the line II-II to the corresponding position of the view in 2 , In 3 is initially from bottom to top of the carrier 4 shown on which directly the stripes 5 made of magnetic field shielding material, with free spaces 6 are applied between them. About the strip 5 there is an insulator layer 7 , on which in turn the transponder is applied. In 3 are only the cross sections of the tracks of the antenna structure 8th shown. On the tracks of the An antenna structure 8th of the transponder 2 is a cover material 9 arranged, which the antenna structure 8th covering upwards. The connection of the individual layers is not shown further, but can be done directly via adhesive bonds, for example in the present case.

In In the present embodiment, the side edge portions are the entire assembly not by a filling or adhesive material completed, and form together with the other elements consequently not a complete unit. Yet would be such a filling or completion conceivable. In addition, it would also be conceivable that stabilizing elements or mold elements in the illustrated Layer sequence to be inserted, which application-specific Requirements for the arrangement bill. For example, lateral reinforcements in the layer sequence of the arrangement to be integrated with the arrangement to stabilize. Likewise, form elements could be integrated which maps the entire array to a specific surface topography to adjust.

4 illustrates a second embodiment of the magnetic field shield 1 being on the magnetic field shield 1 attached transponder 2 out 2 equivalent. The planar transponder again defines a first area section (a). The carrier in turn defines a second area section (b). The main difference between the illustrated magnetic field shielding 1 and those out 2 lies in the transverse arrangement of the strips 5 , which laterally with appropriate open spaces 6 are arranged in a parallel manner to each other. In the illustrated embodiment of the magnetic field shield 1 are a total of 10 strips 5 intended. Crucial in the present arrangement, however, is that if anisotropic permeability of the shielding material is provided, the increased permeability of the shielding material will not be solely along the longitudinal edges of the strips 5 and can run parallel to the visible surface. According to the invention, an increased permeability is then perpendicular to the longitudinal edges of the strips 5 provided parallel to the visible surfaces.

5 illustrates a third embodiment of the magnetic field shield 1 being on the magnetic field shield 1 attached transponder 2 again in the construction of the 2 equivalent. The main difference between the illustrated magnetic field shielding 1 and the off 2 or 4 lies in the wavy shape of the stripes 5 , which along with corresponding open spaces 6 in a parallel manner to each other on the carrier 4 are arranged. In the illustrated embodiment of 5 are in total 5 Strip provided, but which can be arbitrarily changed in number according to the invention. It is crucial to the present arrangement that, if an anisotropic permeability of the shielding material is provided, for a design according to the invention of the magnetic field shield 1 a direction of increased permeability not exclusive to the wave structure of the strips 5 may follow, but for example, essentially the orientation of the running from top to bottom interconnects of the antenna structure 8th follows.

The same thought is also in 6 illustrates which one to the antenna structure 8th oblique arrangement of the stripes 5 represents. Again, the in. Corresponds 6 shown transponder 2 the transponders shown above 2 out 2 . 4 and 5 , Also in the illustrated arrangement, for example, an increased permeability is primarily due to the alignment of the top-to-bottom interconnects of the antenna structure 8th of the transponder 2 oriented, if an anisotropic permeability of the shielding material is provided.

7 illustrates another possible embodiment of the magnetic field shield according to the invention 1 which has an L-shaped strip shape for the two outermost strips 5 , relative to the edge of the carrier 4 , provides. By such an arrangement can be ensured that the strips 5 are aligned parallel to each other in essential sections, wherein the longitudinal edges of the strips 5 in the current flow direction, in particular in the direction of the conductor tracks of essential sections of the antenna structure 8th run.

8th illustrates another variant of an embodiment of the magnetic field shield according to the invention 1 , In this embodiment, the stripes run 5 in such areas from top to bottom, in which also the conductor tracks of the antenna structure 8th have such a course. In the remaining areas, the stripes run 5 from left to right, where also the tracks of the antenna structure 8th have a gradient from left to right. Consequently, this arrangement also ensures that the strips 5 are aligned parallel to each other in essential sections, wherein the longitudinal edges of the strips 5 in the current flow direction, in particular in the direction of the conductor tracks of essential sections of the antenna structure 8th run.

An alternative overall geometry of a magnetic field shield according to the invention 1 is in 9 demonstrated. In the illustrated arrangement, the carrier 4 circular shaped. On the carrier 4 are ring segment-shaped strips 5 arranged concentrically, with constant free spaces 6 between these. A ring segment-shaped arrangement has in contrast to a purely annular arrangement, the advantage that an induced in the rings opposing field is prevented. In the illustrated arrangement are 4 strips 5 provided, the number of which can be changed as desired by a person skilled in the art. On the carrier 4 With stripes 5 is a substantially spiral, flat antenna structure 8th arranged with a microchip 10 to a transponder 2 is interconnected. Also in this geometry, the planar transponder again defines a first area section (a). The carrier in turn defines a second area section (b). If an anisotropic permeability of the shielding material is provided, in an embodiment according to the invention an increased permeability of the strips follows 5 essentially the conductor tracks of the antenna structure 8th ,

At It should be noted that all of the above Parts seen on their own and in any combination, in particular the details shown in the drawings as essential to the invention be claimed. Variations thereof are those skilled in the art common.

1

magnetic shielding

2

RFID transponder

4

carrier

5

strip

6

free space

7

insulator layer

8th

antenna structure

9

cover material

10

microchip

11

antenna bridge

a

1. surface section

b

Second surface section

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• DE 10017142 A1 [0007]
• EP 1594082 A1 [0008]
• - DE 10149126 A1 [0009, 0010]

Claims (31)

Magnetic field shielding device ( 1 ) of an RFID transponder ( 2 ) with respect to a substrate, which on a first surface section (a) has at least one flat antenna structure ( 8th comprising conductor tracks for conducting current in a current flow direction and having an application-specific extension, the device comprising a second area section (b) or carrier ( 4 ) on which strip ( 5 ) are arranged in a predetermined manner aligned with each other, wherein the second surface portion (b) to the first surface portion (a) is arranged in parallel, characterized in that the highly permeable shielding material has an anisotropic permeability, wherein an increased permeability in the Current flow direction, in particular in the direction of the tracks of essential sections of the antenna structure ( 8th ) is provided. Magnetic field shielding device ( 1 ) of an RFID transponder ( 2 ), which on a first surface section (a) has at least one flat antenna structure ( 8th comprising conductor tracks for conducting current in a current flow direction and having an application-specific extension, the device comprising a second area section (b) or carrier ( 4 ) on which strip ( 5 ) of a high-permeability shielding material are arranged in a predetermined manner aligned with each other, wherein the second surface portion (b) to the first surface portion (a) is arranged in parallel, characterized in that the strips ( 5 ) are parallel aligned in essential sections and by free spaces ( 6 ) between longitudinal edges of the strips ( 5 ) are spaced, wherein the longitudinal edges of the strips ( 5 ) in the current flow direction, in particular in the direction of the conductor tracks of essential sections of the antenna structure ( 8th ) are provided. Device according to claim 1, characterized in that the strips ( 5 ) aligned substantially parallel to each other and by free spaces ( 6 ) between longitudinal edges of the strips ( 5 ) are spaced. Device according to one of claims 1 to 3, characterized in that the shielding material has an electrical conductivity which is lower than that of the substrate on which the magnetic field shield ( 1 ) is applied. Device according to one of claims 1 to 4, characterized in that the shielding material has an electrical conductivity which is less than the conductivity of the material of the antenna structure ( 8th ). Device according to one of claims 1 to 5, characterized in that the shielding material iron, Nickel, cobalt, gadolinium, compounds of the substance group of garnets, such as yttrium-aluminum compounds, alloys from the above Substances or samarium, as well as amorphous metals. Device according to one of claims 1 to 6, characterized in that the shielding material is a soft magnetic Metal with low core losses, in particular a μ metal, includes. Device according to one of claims 1 to 7, characterized in that the shielding material is nano-crystalline Structures includes. Device according to one of claims 1 to 8, characterized in that the strips ( 5 ) are flexible and have a thickness of less than 500 .mu.m, preferably less than 100 .mu.m, in particular less than 50 .mu.m. Device according to one of claims 1 to 9, characterized in that the strips ( 5 ) are arranged one above the other in a plurality of layers separated by insulator layers. Device according to one of claims 1 to 10, characterized in that the carrier ( 4 ) consists of a substantially electrically non-conductive material. Device according to one of claims 1 to 11, characterized in that the carrier ( 4 ) as an inlay of an RFID transponder ( 2 ) is trained. Device according to one of claims 1 to 12, characterized in that the carrier ( 4 ) with the RFID transponder ( 2 ) is enclosed in plastic, paper or film laminate, wherein preferably at least one insulator layer ( 7 ) between carriers ( 4 ) and RFID transponders ( 2 ) is provided. Device according to one of claims 1 to 13, characterized in that a surface portion which of the strips ( 5 ) on the second surface section (b) is at least as large as the first surface section (a) and this covered. Device according to one of claims 1 to 14, characterized in that the RFID transponder ( 2 ) operates in the RF frequency range, in particular at 13.56 MHz. Method for producing a magnetic field shield ( 1 ) of an RFID transponder ( 2 ) which on a first surface section (a) has at least one flat antenna structure ( 8th comprising conductor tracks for conducting current in a current flow direction and having an application-specific extent, the method comprising providing a second area section (b) or carrier ( 4 ) on which strip ( 5 ) of a high-permeability shielding material are arranged in a predetermined manner aligned with each other, wherein the second surface portion (b) to the first surface portion (a) is arranged in parallel, characterized in that the high-permeability shielding material is prepared with an anisotropic permeability, wherein the shielding material such relative to the antenna structure ( 8th ), that an increased permeability in the current flow direction, in particular in the direction of the tracks of essential portions of the antenna structure ( 8th ). Method for producing a magnetic field shield ( 1 ) of an RFID transponder ( 2 ), which on a first surface section (a) has at least one flat antenna structure ( 8th comprising conductor tracks for conducting current in a current flow direction and having an application-specific extent, the method comprising providing a second area section (b) or carrier ( 4 ) on which strip ( 5 ) of a high-permeability shielding material are arranged in a predetermined manner aligned with each other, wherein the second surface portion (b) to the first surface portion (a) is arranged in parallel, characterized in that the strips ( 5 ) are parallel aligned in essential sections and by free spaces ( 6 ) between longitudinal edges of the strips ( 5 ), the longitudinal edges of the strips ( 5 ) in the current flow direction, in particular in the direction of the conductor tracks of essential sections of the antenna structure ( 8th ). Method according to claim 16, characterized in that the strips ( 5 ) aligned substantially parallel to each other and by free spaces ( 6 ) between longitudinal edges of the strips ( 5 ) are spaced. Method according to one of claims 16 to 18, characterized in that the shielding material has an electrical conductivity which is lower than that of the substrate on which the magnetic field shielding (FIG. 1 ) is applied. Method according to one of claims 16 to 19, characterized in that the strips ( 5 ) are produced by etching a full-area shielding material. A method according to claim 20, characterized in that the full-surface shielding material on the carrier ( 4 ) is laminated in a roll-to-roll process. Method according to one of claims 16 to 19, characterized in that the strips ( 5 ) are produced by a machining mechanical molding process. Method according to one of claims 16 to 19, characterized in that the strips ( 5 ) are produced by a non-chip mechanical forming process. Method according to one of claims 16 to 19, characterized in that the strips ( 5 ) are prepared by a wet chemical process. Method according to one of claims 16 to 19, characterized in that the strips ( 5 by physically or chemically depositing the shielding material on the support ( 4 ) getting produced. Method according to one of claims 16 to 19, characterized in that an anisotropy of the permeability of the high permeability material by means of a magnetic directional field induced or amplified. Method according to one of claims 16 to 26, characterized in that the fixation of the strips ( 5 ) on the support ( 4 ) by means of an adhesive or a paint. Method according to one of claims 16 to 27, characterized in that the carrier ( 4 ) after fixing the strips ( 5 ) on it with the RFID transponder ( 2 ) is connected. Method according to one of claims 16 to 28, characterized in that the carrier ( 4 ) before fixing the strips ( 5 ) on it with the RFID transponder ( 2 ) is connected. Method according to one of Claims 16 to 29, characterized in that the connection of RFID transponders ( 2 ) and device for magnetic field shielding ( 1 ) by means of folding, laminating or an encapsulation process. Use of a device for magnetic field shielding ( 1 ) of an RFID transponder ( 2 ) according to one of claims 1 to 15, for reducing the loss of function caused by eddy current losses of the RFID transponder ( 2 ).