US20040244865A1 - Smart label - Google Patents

Abstract

A smart label device having at least one textile backing, at least one flexible wire-like and/or thread-like electrical conductor, which is arranged on or in the textile backing and has at least one connection point for an electronic component, and at least one electronic component, which is electrically connected to the connection point of the conductor.

Description

CROSS-REFERENCE TO RELATED APPLICATION
• This application is a continuation of International Patent Application Serial No. PCT/EP02/12577, filed Nov. 11, 2002, which published in German on May 22, 2003 as WO 03/042911, and is incorporated herein by reference in its entirety.[0001]
FIELD OF THE INVENTION
• The invention relates to a device with an electronic component in a textile surrounding and to a method for producing the device.[0002]
BACKGROUND OF THE INVENTION
• “Smart labels”, as they are known, will in future become highly significant in the textiles sector in respect of the logistics of the production process, sales and the care for or cleaning of textiles. For example, smart labels may be provided with contactlessly scannable transponder systems (known as RFID tags), by means of which for example textile-specific information can be retrieved. Examples of preferred application areas for textiles provided with such tags are appropriate labeling of rented laundry, laundry in laundry establishments or stock keeping. Of particular significance in this connection is that the “smart label” is resistant to the production and cleaning processes usually used for textiles and also withstands use of the textiles for their intended purposes. If the textiles labeled in this way are items of clothing, they should also not detract from their comfort when they are being worn or used.[0003]
• Conventional “smart labels” typically comprise a small silicon chip which contains a processor, a device for data transmission (for example a modulator) and a limited memory for receiving specific data. Also provided is an integrated coil, which together with a capacitor and the silicon chip forms an oscillating circuit, the resonant frequency of which is tuned to a specific frequency. Typical frequencies used are 13.56 MHz and also 135 kHz. The coil, which is an electrical conductor loop with one or more turns, is brought into the alternating magnetic field of a transmitting antenna for the reading process of the contactless transponder system, so that an inductive coupling between the transmitter and the antenna coil of the “smart label” is set up. The alternating magnetic field has the effect of inducing an electrical voltage in the coil, which is used in rectified form for the voltage supplied to an integrated transponder circuit (transponder IC or RFID chip). For commonly used frequencies and permissible field strengths, loop areas of approximately 25 cm[0004]²and 1 to 10 coil turns are customary.
• Such a conventional “smart label” is represented in FIG. 4. The[0005]coil100 comprisesmetallic conductor tracks102 applied to a thin film of plastic (not visible in FIG. 4) in a planar arrangement with a spiral structure. Themetallic conductor tracks102 may either be printed on or etched out by a lithographic step and a subsequent etching process from a film coated for example with copper. The structuring process is typically followed by electrochemical reinforcement of theconductor tracks102 to achieve a low series resistance of thecoil100. The transponder IC104 (known as the RFID chip) is brought into electrical contact on one side of thecoil100. On the rear side of the film there is a metal bridge (not represented in FIG. 4), through which electrical contact has to be established in order to realize a connection between the two ends of the coil and thechip104.
• Adverse aspects of such conventional “smart labels” are the complex structuring process and the high series resistance of the coil, which results in poor quality of the resonant oscillating circuit. Furthermore, the planar coil requires a relatively large area, since the coil turns have to be arranged next to one another. However, it is particularly disadvantageous that the coil has to be applied to a backing film which is relatively rigid and poorly suited for textile applications. Such a coil which is applied to a backing film represents a foreign body in textile applications, which in particular reduces the wearing comfort of an item of clothing. Moreover, conventional film-based coil systems are not stable over long periods of time in textile applications, since they can only withstand to a limited extent the loads typically occurring (for example stretching, folding, ironing, washing cycles, changes in temperature and exposure to moisture). Furthermore, such a “smart label” can be seen and/or felt, which may be detrimental, in particular for uses in items of clothing, and hinders use as a guard against forgery and/or theft, for example in high-quality brand-name articles of clothing.[0006]
• The prior art also discloses the use of contactless transponder systems for “smart labels” in which the transponder IC is accommodated in a coin-shaped hard plastic disk, in which the antenna coil is also located. Such conventional systems are even worse than the film-based systems described at the beginning for being embedded in textile surroundings.[0007]
SUMMARY OF THE INVENTION
• In view of the stated disadvantages of the prior art, it is an object of the invention to provide a device, in particular a “smart label”, which can be integrated well in a textile surrounding and withstands the loads occurring therein. It is also an object of the invention to provide a corresponding method for producing such a device.[0008]
• This object is achieved by a device and a method according to the independent claims. Preferred embodiments are the subject of the dependent claims.[0009]
• According to the invention, a device, in particular a “smart label” for textiles, comprises at least one textile backing, at least one flexible wire-like and/or thread-like electrical conductor, which has at least one connection point for an electronic component, and at least one electronic component, which is electrically connected to the connection point of the conductor, wherein the conductor is arranged on or in the textile backing.[0010]
• According to the invention, the conductor, which may be for example a spiral-shaped antenna coil of a transponder system, is flexible and is of a wire-like and/or thread-like form. These flexible properties of the conductor allow it to be arranged directly in or on a textile backing. As a difference from known “smart labels”, the device according to the invention does not represent a foreign body in a textile surrounding, since neither a backing film nor a hard housing has to be used. A device according to the invention consequently has considerably improved wearing comfort and also more advantageous loading properties in comparison with the conventional “smart labels” explained at the beginning.[0011]
• The textile backing is preferably a woven fabric. A woven fabric is understood here as meaning a textile fabric made up of two systems of threads, crossing in particular at right angles, which are referred to—as usual—as warp and weft. The warp lies in the longitudinal direction of the weaving process, while the weft direction extends transversely to the weaving direction. The textile backing may be, for example, a portion of woven fabric which, together with the conductor or conductors arranged on or in it, can be applied for example to a textile to be labeled. Alternatively, the textile backing may also be the textile itself that is to be provided with a device according to the invention.[0012]
• According to a preferred embodiment of the invention, the woven fabric has at least one electrically conductive weft and/or warp thread and the conductor comprises at least one electrically conductive weft and/or warp thread of the woven fabric. In this case, the conductor is arranged in the textile backing and itself represents part of the woven fabric of which the textile backing consists. As a result of the fact that the conductor, which may be for example an antenna coil for a transponder IC, is a component part of the textile backing itself, such a device according to the invention can be embedded particularly well in a textile surrounding.[0013]
• The conductor preferably comprises at least one electrically conductive weft thread and at least one electrically conductive warp thread, which are connected electrically conductively to one another at their crossing point. For example, in a simple woven textile structure, two wiring levels which extend perpendicularly to one another and are independent of one another may be provided by corresponding electrically conductive weft and warp threads, which can specifically be electrically connected to one another at their crossing points. The contacting process of a weft thread with a warp thread at their crossing point may take place for example by means of a stamp or a roller, in particular by a fusing, soldering or adhesive-bonding operation. Consequently, suitable electrical connections of warp and weft threads can be used to produce a complex path of the electrical conductor in the woven fabric in a simple way.[0014]
• The conductor preferably comprises a multiplicity of electrically conductive weft and warp threads, some of which are connected electrically conductively at their crossing points in such a way that the conductor forms an electrically conductive coil. Such a coil arranged in the textile backing typically has a rectangular spiral form and represents a planar conductor arrangement. The electrically conductive weft or warp threads are preferably surrounded by an insulating sheathing, so that undesired short-circuits at weft and warp crossing points can be avoided in a simple way. The choice of a suitable point-contacting pattern of warp and weft threads allows the problem of “back-wiring”, occurring in the case of conventional, film-based planar coils, to be solved in a simple way without a bridge. Although, as in the prior art, a substantially planar conductor arrangement is consequently concerned, unlike in the case of film-based coils no bridge is necessary for returning the contact inside the coil to the outer contact (or vice versa).[0015]
• The conductor preferably has two connection points, which form the coil connections and are electrically connected to the electronic component. The connection points of the conductor may be, for example, weft and/or warp threads, which are connected to contact areas of the electronic component, for example by a soldering or adhesive-bonding step.[0016]
• The electrically conductive weft and/or warp thread is preferably an electrically conductive yarn which comprises electrically insulating fibers and at least one metal wire embedded or spun therein. Alternatively, the electrically conductive weft and/or warp thread may also directly comprise a thin metal wire, for example a copper wire. Such metal wires, possibly spun with insulating fibers, are more robust and flexible than conductor tracks printed onto a film. Moreover, metal filaments or wires which are specifically surface-treated for the special surrounding conditions of textiles can be advantageously produced. In particular in comparison with coils produced by printing processes, metal wires generally have a higher electrical conductivity.[0017]
• A further advantage in comparison with coils structured by etching processes on films is also the lower metal consumption when metal wires are used. This is so because, in production of conductor tracks by an etching process, a large part of the metal layer has to be removed for the definition of the metal track and must be recovered from the etching solution, causing costs to be incurred. If, for example, the conductor is designed as a spiral coil for an antenna coil of a transponder IC, a coil with comparable inductance but considerably increased quality can be produced by the invention. The metal wire preferably has an electrically insulating sheathing.[0018]
• According to a further preferred embodiment, the conductor is not arranged in the textile backing but on the same. The conductor preferably has for this purpose a metal wire, which in particular has an electrically insulating sheathing.[0019]
• The conductor is preferably an electrically conductive yarn which comprises electrically insulating fibers and at least one metal wire embedded or spun therein. Although such a conductor is more voluminous due to the additional textile thread, it is also given a stronger textile character. When it is connected to the electronic component, it must be ensured in this case that the textile thread (which is not electrically conductive) does not disturb the contacting with respect to the metal wire.[0020]
• The conductor is preferably connected to the textile backing by an adhesive bond. In particular, the textile backing may be coated with an adhesive, for example a hot-melt adhesive, which is preferably made possible by ironing the conductor on. If the conductor is an electrically conductive yarn, it may be additionally provided, if appropriate, with an adhesive, for example in that it is impregnated with adhesive.[0021]
• The conductor may be an electrically conductive coil, which has for example been wound spirally around a hollow body and placed and fixed on the textile backing.[0022]
• A second textile backing may advantageously be arranged on the first textile backing in such a way that the conductor is embedded between the backings. This assembly of two textile backings with an electrical conductor arranged between permits particularly efficient mechanical protection of the conductor and a high load-bearing capacity of the device according to the invention. The electronic component is also advantageously arranged between the two textile backings.[0023]
• The electronic component may be an integrated circuit (IC), in particular a transponder IC (known as an RFID chip). In connection with a conductor, which represents a spiral, electrically conductive coil, this is a way of creating a contactlessly readable transponder system which can be integrated in a textile surrounding in an outstanding way.[0024]
• The electronic component is preferably embedded in an insulator and attached to the textile backing. A waterproof and soft material is expediently used for the insulator.[0025]
• According to the invention, a method for producing a device, in particular a device described above, comprises the steps of:[0026]
• providing at least one textile backing, on or in which at least one flexible wire-like and/or thread-like electrical conductor is arranged, the conductor having at least one connection point for an electronic component; and[0027]
• electrically connecting the connection point of the conductor to at least one electronic component.[0028]
• The textile backing is preferably a woven fabric and the conductor preferably has a multiplicity of electrically conductive weft and warp threads, the method comprising the step of electrically connecting at least one weft thread to a warp thread at their crossing point. Alternatively, the conductor may be connected to the textile backing by an adhesive bond.[0029]
• Compared with conventional “smart labels”, a device according to the invention has the following advantages.[0030]
• The electrical conductivity of a metal wire used in the electrically conductive wire-like and/or thread-like conductor is higher than that of conventionally used conductor tracks on plastic films. This is manifested for example in a higher quality of an antenna coil which can be formed by the conductor.[0031]
• A loss of material, which is inherently involved in the production process of a conventional antenna coil, does not occur in the case of a production method according to the invention.[0032]
• If the conductor is to be used in the form of a coil, a device according to the invention allows the coil connections to be led out without “back-wiring” with a bridge, as was necessary in the case of conventional coils.[0033]
• By contrast with conventional devices, no substrate film on which the otherwise customary thick-film processes were applied is necessary.[0034]
• The production method according to the invention can be reeled off from spindles in a highly parallel manner.[0035]
• The “textile label” can be outstandingly incorporated in a textile surrounding and can be comfortably worn, washed and ironed.[0036]
• If a washing or manufacturer label is used as the backing for the conductor, no additional textile backing is necessary.[0037]
BRIEF DESCRIPTION OF THE DRAWINGS
• The invention is described below by way of example with reference to preferred exemplary embodiments on the basis of accompanying drawings, in which:[0038]
• FIG. 1([0039]a) shows a schematic representation of an endless fabric strip, in which thread-like conductors are incorporated in the warp direction and with a specific repeat in the weft direction
• FIG. 1([0040]b) shows a schematic representation of a detail from the fabric strip shown in FIG. 1(a), the thread-like conductor forming by means of local contacting points an electrically conductive coil;
• FIG. 2([0041]a)-(d)shows schematic representations of a method for contacting a wire-like or thread-like conductor at contact areas of an electronic component;
• FIG. 3 shows schematic representations of the electronic component contacted and cast in an insulator; and[0042]
• FIG. 4 shows a conventional “smart label” with a metal track coil on a film base.[0043]
DETAILED DESCRIPTION OF THE PREFERRED MODE OF THE INVENTION
• Schematically shown in FIG. 1([0044]a) is an endless fabric strip in which wire-like or thread-like conductors10 have been woven, for example on a loom for narrow fabrics. These electrically conductive threads extend both in the warp direction Wa (longitudinal direction) and with a specific repeat in the weft direction We (transverse direction). Such an arrangement may also be produced two-dimensionally on a loom for sheet-like fabrics. Each of theconductors10 indicated by a black line may comprise one or more conductive threads. Theconductors10 may also be yarns, in the case of which a thin metal wire is spun with at least one insulating fiber, for example a synthetic fiber. Alternatively, a thin metal wire may also be used directly as the wire-like conductor.
• Represented in FIG. 1([0045]b) is a detail from the endless strip shown in FIG. 1(a). The electrically conductive weft andwarp threads10 running over one another can be connected at the crossing points by suitable local contactingpoints12, which are schematically represented in FIG. 1(b) as black dots. The contacting points12 of the individualelectrical conductors10 may be embossed by a die or a roller, in particular by fusing, soldering or adhesive bonding of themetallic conductors10. In FIG. 1(b), the contactingpoints12 form a spiral conductor, which has a planar coil structure. For better illustration of the electrical conduction path, the coil is emphasized in FIG. 1(b) by a dashed line.
• Accordingly, the 4×5 contacting[0046]points12 respectively connect two conductor tracks to one another, i.e. in each case a weft thread to awarp thread10, so that a spiral current path is formed through the woven fabric. An additional contactingpoint14 allows the current path to be led out from the interior of the coil without a bridge being necessary, as in the prior art, as a “back-wiring means”. The pieces of theconductors10 protruding laterally beyond the coil have no effect, since their ends are open and no current can flow. If desired, the edges of the woven fabric may be additionally insulated, which can take place for example by encapsulation using casting or fusing techniques. Furthermore, portions of line which are not required can optionally be severed by a knife or a punch. At connection points of theconductor10, which in this case represent the connections of the electrically conductive coil, a transponder IC (RFID chip) is connected.
• In the case of the embodiment just described of a device according to the invention, the[0047]conductor10 is arranged in the textile backing, in which electrically conductive weft or warp threads of the textile backing comprising a woven fabric are used asconductors10. However, it is alternatively possible as it were to form the conductor from a thin, flexible, wire-like and/or thread-like material which is electrically conductive. In a subsequent production step, such a conductor is arranged on the textile backing, for example by means of an adhesive step. A thin coil wire, for example a copper wire, which is sheathed with silver and insulating varnish, as also produced and used for conventional coils and transformers, is suitable in particular for such a conductor.
• In order for example to produce an antenna coil for a transponder IC, such a thin coil wire is preferably wound around a hollow body, on which the beginning and end of the wire are firmly clamped by means of a holding device. Immediately thereafter, the beginning and end of the wire are attached in an electrically conducting manner to the transponder IC, as described in detail later. Subsequently, the transponder IC may be sealed with a drop of insulating, wash-resistant and temperature-resistant plastic and subsequently placed on the textile backing, which has been coated for example with hot-melt adhesive for textiles, by stripping it from the winding device. The transponder IC with the coil is fixed on the textile backing by brief heating and application of pressure. The textile backing with the “smart label” created in this way can subsequently be ironed into a textile and assume its function. After the operation of ironing it onto the textile, which may be for example an item of clothing or an item of laundry, the coil with the transponder IC is protected from both sides by woven textile fabric and no longer needs any additional encapsulation.[0048]
• It is likewise possible to wind the coil from a textile thread in which a metal wire has been spun. Although the coil is rather more voluminous as a result, it has a stronger textile character. When it is connected to the chip, it must be ensured in this case that the textile thread does not disturb the contacting with respect to the metal wire. If appropriate, it is even possible to impregnate the thread with the textile adhesive and to realize the connection of the individual conductors to one another and to the textile backing by the thread.[0049]
• Coil wires have proven to be particularly suitable for the thin metal wires used, for example the coil wire TW-D with a diameter of 40 μm from the company Elektro-Feindraht AG, Eschholzmatt, Switzerland. This copper wire is silver-coated and provided with a polyamide insulating varnish. It has been specifically tested for textile applications and proven to be washable and also resistant to dry cleaning and temperatures of up to 100° C.[0050]
• In order to produce an inductance corresponding to a conventional “smart label” according to FIG. 4, such a wire is preferably wound up on a winding device. The winding device may be, for example, a cuboidal body with an edge length of 2.7 cm or a round cylinder with a diameter of 3.04 cm, onto which seven turns of the copper wire are wound. The winding device has two clamps, by which the beginning and end of the wire can be fixed.[0051]
• On the winding device itself, the transponder IC is brought into electrical contact with the ends of the wire, which is represented in FIGS.[0052]2(a) to (d). This advantageously takes place by a low-meltingsolder paste20 being printed onto thecontact areas18 of thetransponder IC16—as represented in FIG. 2(b). Thesolder paste20 may comprise for example solder balls and a flux. PbAgSn is suitable in particular as the solder. Thereafter, the connection points of theconductor10 are arranged on thecontact areas18 prepared in this way of thetransponder IC16 and locally heated, for example by means of a gas flame, a laser or an electric arc, until the solder melts and bonds with thewire10. Theconductor10 used has an insulatingsheathing22, which is removed by the heat effect (schematically represented by a lightning symbol in FIG. 2(c)). During the positioning and connecting operation, theconductor10 is held by means of holdingclamps24 in relation to thecontact areas18 covered with solder paste. The result of the electrical and mechanical fixing by the heating operation is schematically represented in FIG. 2(d).
• The transponder IC contacted in this way is subsequently encapsulated by applying to it a drop of sealing[0053]compound26, which makes the chip resistant to washing and ironing and mechanically protects it. A waterproof and soft insulator is particularly suitable for the sealingcompound26. Thewound coil wire10 with thetransponder IC16 prepared in this way is stripped from the winding device and placed onto a textile backing, which is preferably coated with a layer of hot-melt adhesive for textiles. The loosely wound coil with the chip is fixed on the textile backing by brief heating and application of pressure. The preferred device according to the invention prepared in this way can then be ironed onto an item of clothing or some other textile. The coil with the transponder IC is then protected on both sides by textile and withstands even relatively great mechanical loads. The conductor used, preferably a coil wire, is so flexible that it can be adapted well to the woven fabric and cannot be snapped off by bending.
• It is particularly preferred for the device according to the invention to be placed in a manufacturer or material label flap which has already been attached to the item of clothing and coated on its inner surfaces with textile adhesive. The coil with the transponder IC can be fixed in the label flap by an operation in which heat and pressure are applied.[0054]

Claims (20)

1. A device, in particular a smart label, comprising:

at least one textile backing, which is a woven fabric;

at least one flexible wire-like and/or thread-like electrical conductor arranged on or in the textile backing; and

at least one electronic component, which is electrically connected to a connection point of the conductor;

wherein the woven fabric has at least one electrically conductive weft and warp thread and the conductor comprises at least one electrically conductive weft and warp thread of the woven fabric, which are connected electrically conductively at their crossing point in such a way that the conductor forms an electrically conductive coil.

2. The device as claimed inclaim 1, wherein the conductor comprises a multiplicity of electrically conductive weft and warp threads, some of which are connected electrically conductively at their crossing points such that the conductor forms an electrically conductive coil.

3. The device as claimed inclaim 2, wherein the conductor has two connection points, which form coil connections and are electrically connected to the electronic component.

4. The device as claimed inclaim 1, wherein the electrically conductive weft and/or warp thread is an electrically conductive yarn which comprises electrically insulating fibers and at least one metal wire embedded therein.

5. The device as claimed inclaim 4, wherein the metal wire has an electrically insulating sheathing.

6. The device as claimed inclaim 1, wherein the conductor has at least one metal wire.

7. The device as claimed inclaim 6, wherein the metal wire has an electrically insulating sheathing.

8. The device as claimed inclaim 6, wherein the conductor is an electrically conductive yarn which comprises electrically insulating fibers and at least one metal wire embedded therein.

9. The device as claimed inclaim 6, wherein the conductor is connected to the textile backing by an adhesive bond.

10. The device as claimed inclaim 9, wherein the textile backing is coated with an adhesive.

11. The device as claimed inclaim 10, wherein the adhesive is a hot-melt adhesive.

12. The device as claimed inclaim 8, wherein the electrically conductive yarn is provided with an adhesive.

13. The device as claimed inclaim 6, wherein the conductor forms an electrically conductive coil.

14. The device as claimed inclaim 6, further comprising a second textile backing arranged on the first textile backing in such a way that the conductor is embedded between the backings.

15. The device as claimed inclaim 1, wherein the electronic component is an integrated circuit.

16. The device as claims inclaim 15, wherein the integrated circuit is a transponder integrated circuit.

17. The device as claimed inclaim 1, wherein the electronic component is embedded in an insulator and arranged on the textile backing.

18. A method for producing a device comprising the steps of:

providing at least one textile backing, on or in which at least one flexible wire-like and/or thread-like electrical conductor is arranged;

electrically connecting a connection point of the conductor to at least one electronic component;

wherein the textile backing is a woven fabric and the conductor has in each case at least one electrically conductive weft and warp thread; and

electrically connecting at least one weft thread to a warp thread at their crossing point, so that the conductor forms an electrically conductive coil.

19. The method as claimed inclaim 18, wherein the conductor has a plurality of electrically conductive weft and warp threads, and the method further comprises the step of electrically connecting at least a portion of the weft and warp threads at their crossing points, so that the conductor forms an electrically conductive coil.

20. The method as claimed inclaim 18, wherein the conductor is connected to the textile backing by an adhesive bond.

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