ZA200305695B

ZA200305695B - Detection or identification resonant antenna and method for making same.

Info

Publication number: ZA200305695B
Application number: ZA200305695A
Authority: ZA
Inventors: Tony Bernard
Original assignee: Pygmalyon
Priority date: 2001-11-30
Filing date: 2003-07-23
Publication date: 2004-02-23
Also published as: WO2003047028A1; FR2833109A1; FR2833109B1; AU2002361360A1; NO20033380L; NO20033380D0; BR0206786A

Description

CL ~ +2003/08965

Resonant antenna for detection or identification and its production method

The present invention relates to the technical field of thin resonant antennas for transponder units generally including at least one electronic chip associated with the antenna.

The invention also relates to the technical field of resonant antennas per se, as used for detection especially in antitheft systems.

Such transponder units are, for example, used in the field of contactless identification

In the above field, a Patent EP-0 753 180 proposes to produce the transponder unit, and the thin antenna especially, by depositing an electrically conductive wire on a substrate and by making an at least point-like connection of the wire on the substrate by adhesively bonding or melting the substrate in a point-like fashion. Such an embodiment is particularly suitable for the manufacture of chip cards, insofar as the substrate on which the antenna and the chip are fixed is substantially rigid and is thermally meltable.

However, this method described by Patent

EP-0 753 180 for fitting wires with a very small cross section on thermally meltable rigid supports is by no means suitable for producing an antenna for a transponder on supports which are flat or in the form of layers with a conductive electrical wire of large cross section.

Furthermore, the method advocated by Patent

EP-0 753 180 entails the use of a complex and expensive material, the price of which substantially increases the manufacturing cost of the antennas.

There hence appears to be a need to provide a method for manufacturing a thin antenna for a transponder which is suitable for fitting an antenna wire for a transponder on supports which are flexible or in the form of layers, as well as on thin flat supports, and which has a low operational cost.

In order to achieve this object, the invention relates to a method for fitting a thin antenna on a support, of the type consisting in producing at least one turn consisting of at least one electrically conductive wire, which is put on the support and fixed on the latter. According to the invention, this manufacturing method is characterized in that it consists in holding the wire on the support with mechanical holding means which are put on the support and which ensure at least point-like holding of the wire with positive transverse immobilization of the wire with respect to the support.

The invention also relates to a thin antenna for a transponder, of the type comprising at least one turn consisting of at least one electrically conductive wire, fixed on a support which is substantially flat or in the form of a layer. According to the invention, this thin antenna for a transponder is characterized in that the holding of the wire on the support is at least point-like and carried out by holding means which ensure positive transverse immobilization of the wire with respect to the support.

According to the invention, the positive transverse immobilization should be understood by contrast to the fixing advocated by Patent EP-0 753 180, which is carried out by adhesive bonding or adhesion. In the context of the invention, the holding or positive transverse immobilization employs mechanical connection means which form an obstacle against displacement of the conductive wire transversely to its core or to its principal direction, but which do not necessarily prevent an axial translation movement of the wire with respect to the support, and which therefore allow expansion.

In a preferred embodiment, the means for mechanically holding the wire on the support press the wire against the support so as to brake possible axial

® WO 03/047028 - 3 =~ PCT/FR02/04133 translation movements of the wire with respect to the support.

According to one characteristic of the invention, the means for mechanically holding the wire on the support consist of a series of immobilizing through passages, which are arranged according to a pattern corresponding to the shape of the turn, and the continuous conductive wire is arranged in the passages while being located alternately on one or other of the two faces of the support.

According to another preferred characteristic of the invention, the conductive wire is held on only one face of the support with attached mechanical holding means.

According to the invention, these attached mechanical holding means may be produced in any suitable ways. For instance, according to one embodiment, the conductive wire is held by straps or the like, which are secured to the support and press the conductive wire against the support.

The straps may, for example, consist of strips thermally bonded on the support or, alternatively, staples or the like which are engaged in the support, straddling the wire and arranged along the latter.

According to a preferred embodiment of the invention, the conductive wire is stitched on the support. The stitching of the conductive wire that constitutes the turn of the thin antenna may then be carried out in any suitable ways.

According to an alternative embodiment, the conductive wire constitutes one of the two threads of a seam with two threads. The wire that constitutes the turn of the antenna may then be fitted by means of a traditional sewing machine, the bobbin thread then consisting of the conductive wire while the needle thread consists of a textile thread or a non-textile thread of any suitable type.

According to another embodiment of fitting the : conductive wire by stitching, the latter is immobilized

0) WO 03/047028 - 4 - PCT/FR02/04133 on its support by a zigzag seam, the stitches of which are arranged alternately on either side of the conductive wire. Depending on the pitch chosen for producing the zigzag seam, a kind of textile sheath is hence produced around the antenna wire. It should be noted that this way of stitching the antenna wire on the support makes it possible to preserve a degree of freedom in axial translation for the antenna wire, so that the risks of tearing due to deformation of the support are reduced.

Furthermore, the holding of the antenna wire by the mechanical holding means according to the invention has the advantage of allowing the use of conductive wires with a large cross section. According to the invention, the conductive wire constituting the antenna turn or turns may be of any suitable type: singly or multiply stranded, with or without an insulating sheath.

According to one embodiment, the conductive wire is positioned in relation to an electronic transponder chip. Hence, the conductive wire may then be electrically connected to the electronic chip, or simply associated with the latter in the scope of electromagnetic coupling between the conductive wire constituting the antenna and an antenna integrated with the chip per se.

According to the invention, the support of the antenna may be of any suitable type, for example a layer of textile or non-textile, a sheet of paper, a woven layer, a fabric or alternatively a knitted textile.

Hence, the support of the antenna according to the invention may constitute a part of a garment, or alternatively a cover fitted on a piece of furniture or a seat.

According to another embodiment of the invention, the support of the antenna forms at least part of an identifying shirt number, such as those used in the scope of sports competitions.

® WO 03/047028 - 5 - PCT/FR02/04133

Various other characteristics of the invention will become apparent from the following description, given with reference to the drawings which illustrate various nonlimiting embodiments of a thin antenna for a transponder according to the invention.

Figure 1 is a schematic plan view of an antenna according to the invention integrated in an identifying sports shirt number.

Figure 2 is a section on the line II-II in

Figure 1 illustrating a first form of mechanical holding the conductive wire on the support of the antenna by stitching.

Figure 3 is a partial top view of a variant of holding the conductive wire by stitching on its support, as illustrated in Figure 2.

Figure 4 is a partial view of another way of stitching the antenna wire on its support.

Figure 5 is a partial view on the line V-V in

Figure 4.

Figures 6 to 8 illustrate various forms of fixing the conductive wire constituting the antenna according to the invention.

Figure 9 is a top view of another way of fixing a conductive wire constituting the antenna.

Figure 10 is a section on the line of X-X in

Figure 9.

In the scope of a preferred but not exclusive application, the invention proposes to integrate a thin resonant antenna 1 in an identifying shirt number 2 for a sports competition. The shirt number forming the support 2 of the antenna may be made of any suitable material and preferably a flexible material, for example a nonwoven material, a film of synthetic material or alternatively a fabric.

Hence, according to the example that is illustrated, the antenna 1 has three turns of rectangular overall shape 3, 4, 5. According to the invention, of course, the resonant antenna 1 could comprise only a single turn. According to the example

® WO 03/047028 - 6 - PCT/FR02/04133 that is illustrated, the antenna 1 is intended to constitute a feed and transmission antenna for a transponder chip 1, which is also fixed on the support 2. Such a chip 7 does not fall within the scope of the present invention and is well known to the person skilled in the art. As an indication, it may be recalled that that such transponder chips operate at a frequency of about 13,56 MHz and are marketed under various brand names by companies such as PHILIPS or

INSIDE. Of course, the resonant antenna according to the invention may be used at other frequencies.

The resonant antenna 1 in the context of the invention may be referred to as thin insofar as the surface area of its turns is very much greater than the thickness of the antenna, which corresponds substantially to the sum of the diameter of the wire and the thickness of the support 2.

According to an essential characteristic of the invention, the conductive wire 10 constituting the antenna 1 is held by using means 11 for mechanically holding the wire 10 on the support constituting the shirt number 2.

According to the example that is illustrated, the shirt number 2 is made of a nonwoven material in layer form capable of being stitched. For instance, according to this example and as shown by Figure 2, the conductive wire 10 is stitched directly on the support 2. This seam is produced according to a pattern corresponding to the shape of the antenna, by means of a sewing machine whose bobbin thread consists of the conductive wire 10, while the needle thread 11 consists of a thread of any suitable material. The thread 11 then forms the means of immobilizing or mechanically holding the wire on its substrate. According to the example of Figure 2, the tension applied to the conductive wires is substantially equal to that applied to the textile thread, so that they have a substantially symmetrical shape. In the example of

Figure 3, conversely, the tension applied to the conductive wire 10 when it is being stitched is greater than that applied to the textile thread 11, so that the conductive wire 10 is not deformed by the textile thread 11.

According to the invention, the immobilization of the conductive wire 10 constituting the loops or turns of the antenna 1 on the support 2 is not necessarily carried out by direct stitching of the conductive wire 10.

For instance, Figures 4 and 5 illustrate another way of stitched fixing, according to which the conductive wire 10 is held by means of a zigzag seam 15, the various stitches or needle holes 16 of which extend on either side of the conductive wire 10, which then constitutes the running thread. This zigzag seam 15 is made with two textile or synthetic threads 17, 18. Such holding by overstitching furthermore makes it possible, depending on the chosen sewing pitch, to produce a kind of sheath consisting of the threads 17, 18 around the conductive wire 10. Furthermore, the way of holding the antenna wire on the support 2 by stitching according to the invention has the advantage of not degrading the mechanical qualities of the support, in particular the flexibility of the latter.

In addition, the stitching of the antenna wire may be carried out with a simple sewing machine and inexpensively, so that it is possible to obtain products such as, for example, single-use shirt numbers.

According to another embodiment more particularly illustrated in Figure 6, the conductive wire 10 is immobilized or held by means of staples 20 arranged straddling the conductive wire 10. Such staples may be of any suitable type. Instead of staples, it might likewise be envisaged to produce straps or ties in point form around the conductive wire 10, through the support 2.

According to the example illustrated in Figure 7, the conductive wire 10 is held on the support 2 in a sheath 25 put on said support 2. The edges 26 of the sheath 25 are fixed on the support by any suitable means, for example by heat welding or alternatively ultrasonic welding. It might also be envisaged to stitch the sheath 25 on the support 2.

Figure 8 illustrates yet another way of immobilizing the wire 10 on the support 2. According to this embodiment, a series of through passages 30 are formed in the support 2 according to a pattern reproducing the overall shape of the turn constituting the antenna 1. The conductor 10 is then passed successively through the various passages 30 while being located alternately on one face of the support 2 and the other.

Figures 9 and 10 illustrate another way of mechanically holding the conductor 10 by means of straps 35, which are produced in the support 2 and are defined by two parallel slits 36 through which the conductor 10 is successively passed, so that it is then immobilized by clamping.

It should be noted that the ways of holding provided by the invention have the advantage of not degrading the flexibility qualities of the support which is used. Furthermore, according to the examples that are illustrated, the support which is used has a substantially flat shape. However, in the context of holding by stitching, for example but not exclusively, it is possible to integrate or produce the antenna for a transponder directly on a textile element of a garment, for example a sleeve or the like. In the same way, the antenna may be produced in automobile-seat or furniture covers or any other supports, for example postal sacks or bags for packaging products for which traceability needs to be ensured.

In the examples described above, the resonant antenna according to the invention is presented in association with a transponder. However, the antenna according to the invention may be used on its own, or in association with a passive component in order to

® WO 03/047028 - 9 - PCT/FR02/04133 form a simple resonant antenna of the type used for detection in antitheft systems, for example.

The invention is not limited to the examples described above, of course, and various modifications may be made to it without departing from the scope thereof.

Claims

® WO 03/047028 - 10 - PCT/FR02/04133 CLAIMS

1. A thin resonant antenna for detection Or identification, of the type comprising at least one turn (3) consisting of at least one electrically conductive wire (10) fixed on a support (2), characterized in that the fixing of the wire on the support is at least point-like and carried out by mechanical means (11) which ensure positive transverse immobilization of the wire with respect to the support.

2. The antenna as claimed in claim 1, characterized in that: - the support (2) has a series of through passages for immobilizing the wire (10), which are arranged according to a pattern corresponding to the shape of the turn, - and the conductive wire (10) passes through the passages (3) while being located alternately on one of the two faces of the support (2).

3. The antenna as claimed in claim 1, characterized in that the conductive wire (10) is fixed on only one face of the support with attached mechanical fixing means (11, 20, 17, 18).

4. The antenna as claimed in one of claims 1 to 3, characterized in that the conductive wire (10) is fixed by straps (35) or the like, which are secured to the support and press the conductive wire against the support.

5. The antenna as claimed in claim 3, characterized in that the conductive wire is fixed on the support by staples (20) or the like.

6. The antenna as claimed in claim 3, characterized in that the conductive wire (10) is stitched on the support.

7. The antenna as claimed in claim 6, characterized in that the conductive wire (10) constitutes one of the two threads of a seam with two threads.

8. The antenna as claimed in claim 6, characterized in that the conductive wire is immobilized on the support by a zigzag seam (15), the stitches (16) of which are arranged alternately on either side of the conductive wire (10).

9. The antenna as claimed in one of claims 1 to 8, characterized in that the conductive wire (10) is covered with an insulating sheath.

10. The antenna as claimed in one of claims 1 to 9, characterized in that the conductive wire (10) is positioned in relation to an electronic transponder chip (7).

11. The antenna as claimed in claim 10, characterized in that the conductive wire (10) is electrically connected to the electronic chip (7).

12. The antenna as claimed in one of claims 1 to 11, characterized in that the support (2) comprises a layer of textile.

13. The antenna as claimed in one of claims 1 to 12, characterized in that the support (2) forms a part of a garment.

14. The antenna as claimed in one of claims 1 to 12, characterized in that the support (2) forms at least part of an identifying shirt number.

15. The antenna as claimed in one of claims 1 to 14, characterized in that the support 2 is substantially flat or in the form of a layer.

16. A method for manufacturing a thin antenna for a transponder on a support, of the type consisting in producing at least one turn consisting of at least one electrically conductive wire, which is put on the support and fixed on the latter, characterized in that it consists in fixing the wire (10) on the support (2) with fixing means (11, 17, 18, 20, 25) which are put on the support and which ensure at least point-like fixing of the wire (10) with positive transverse immobilization of the wire with respect to the support.

® WO 03/047028 - 12 - PCT/FR02/04133

17. The manufacturing method as claimed in claim 16, characterized in that it consists in stitching the conductive wire (10) on the support (2).