WO2003047028A1

WO2003047028A1 - Detection or identification resonant antenna and method for making same

Info

Publication number: WO2003047028A1
Application number: PCT/FR2002/004133
Authority: WO
Inventors: Tony Bernard
Original assignee: Pygmalyon
Priority date: 2001-11-30
Filing date: 2002-12-02
Publication date: 2003-06-05
Also published as: BR0206786A; FR2833109B1; FR2833109A1; NO20033380L; ZA200305695B; NO20033380D0; AU2002361360A1

Abstract

The invention concerns an antenna comprising at least one coil (3) consisting of at least an electrically conductive wire (10) fixed on a substantially planar or layered support (2). The fixing of the wire on the support is at least point-shaped and produced with mechanical means (11) which ensure positive transverse immobilization of the wire relative to the support.

Description

Resonant detection or identification antenna and its production method -_

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

The invention also relates to the technical field of antennas resonant by themselves as used for detection in anti-theft systems in particular.

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

In the above field, a patent EP-0 753 180 proposed to produce the transponder unit and more particularly the thin antenna by depositing an electrically conductive wire on a substrate and ensuring an at least punctual connection of the wire on the substrate by bonding or spot melting of the substrate. Such an embodiment is particularly suitable for the manufacture of smart cards, insofar as the substrate, on which the antenna and the chip are fixed, is substantially rigid and is found to be hot-melt.

However, this process described by patent EP-0 753 180, for the installation of wires of very small section on rigid hot-melt supports, is in no case suitable for the realization of antenna for transponder on flat or flat supports with an electrical conductor of large section.

Furthermore, the process recommended by patent EP-0 753 180 requires the use of complex and expensive equipment, the damping of which significantly increases the cost of manufacturing the antennas. The need therefore appears to have a method for manufacturing a thin antenna for a transponder which is suitable for placing on flexible or flat supports as well as on thin flat supports, 'antenna for transponder and which has a low cost of implementation. In order to achieve this objective, the invention relates to a method for setting up a thin antenna on a support of the type consisting in producing at least one turn constituted by at least one electrically conductive wire, attached to the support and fixed on the latter. According to the invention, this manufacturing process is characterized in that it consists in ensuring the maintenance of the wire on the support with mechanical holding means which are attached to the support and which ensure at least punctual maintenance of the wire with a positive transverse immobilization of the wire relative to the support.

The invention also relates to a thin antenna for transponder of the type comprising at least one turn constituted by at least one electrically conductive wire, fixed on a substantially flat or flat support. According to the invention, this antenna, of small thickness for transponder, is characterized in that the maintenance of the wire on the support is at least punctual 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 must be understood as opposed to the fixing recommended by patent EP-0 753 180, which is carried out by bonding or adhesion. Within the meaning of the invention, the maintenance or positive transverse immobilization implements mechanical connection means which form an obstacle to a displacement of the conductive wire transversely to its core or to its main direction but which does not necessarily prevent a axial translational movement of the wire relative to the support and therefore allows expansion.

In a preferred embodiment, the means for mechanically holding the wire on the support press the wire against the support so as to slow down any movements of axial translation of the wire relative to the support.

According to a characteristic of the invention, the mechanical holding means, of the wire on the support, consist of a series of immobilizing through passages, arranged in a drawing corresponding to the shape of the turn and the continuous conducting wire is disposed in the passages being located alternately on one or the other of the two faces of the support.

According to another preferred characteristic of the invention, the conductive wire is held on one side of the support with attached mechanical holding means. According to the invention, these added mechanical holding means can be produced in any suitable manner. So according to a form of embodiment, the conductive wire is held by bridges or the like, secured to the support and pressing the conductive wire against the support.

The bridges can be, for example, constituted by heat-sealed strips on the support or even by staples or the like, engaged in the support, straddling the wire and arranged throughout the latter.

According to a preferred embodiment of the invention, the conductive thread is sewn onto the support. The sewing of the conductive wire, constituting the turn of the thin antenna, can then be carried out in any suitable manner.

According to an alternative embodiment, the conductive thread constitutes one of the two threads of a two-thread seam. The establishment of the thread, constituting the turn of the antenna, can then be carried out by means of a traditional sewing machine, the bobbin thread then being constituted by the conducting thread, while the needle thread is constituted by a textile thread or not, of any suitable nature.

According to another form of installation of the conducting wire by sewing, the latter is immobilized on its support by a zigzag seam whose points are arranged alternately on either side of the conducting wire. According to the adopted step, for the realization of the zigzag seam, a kind of textile sheath is thus produced around the antenna wire. It should be noted that this mode of sewing, of 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 rupture, following a deformation of the support , are reduced. Furthermore, the maintenance of the antenna wire, by the mechanical holding means according to the invention, has the advantage of allowing the use of conductive wires of large diameter. According to the invention, the conductive wire, constituting the antenna turns, may be of any suitable nature, single or multi-strand, having an insulating sheath or not. According to one embodiment of the invention, the conducting wire is placed in relation to a transponder electronic chip. Thus, the conductive wire can then be electrically connected to the electronic chip or simply associated with the latter, within the framework of an electromagnetic coupling between the conductive wire, constituting the antenna, and an antenna integrated into the chip in itself. even. According to the invention, the antenna support can be of any suitable nature such as for example a textile tablecloth or not, a sheet of paper, a woven tablecloth, a fabric or even a knitted textile.

Thus, the antenna support, according to the invention, can constitute a part of a garment or even of a cover for covering a piece of furniture or a seat.

According to another embodiment of the invention, the antenna support forms at least part of an identification bib of the type of those used in the context of sports competitions. Various other characteristics of the invention emerge from the description below, made with reference to the drawings which illustrate various nonlimiting embodiments of a thin antenna for transponder, according to the invention.

Figure 1 is a schematic plan view of an antenna according to the invention integrated into a sports identification bib.

Figure 2 is a section along line 11-11 of Figure 1, illustrating a first form of mechanical maintenance, by sewing, of the conductive wire on the antenna support.

FIG. 3 is a partial view from above of a variant for holding the antenna wire by sewing on its support as illustrated in FIG. 2.

Figure 4 is a partial view of another mode of sewing the antenna wire on its support.

FIG. 5 is a partial section along the line V-V in FIG. 4.

Figures 6 to 8 illustrate different forms of attachment of the conductive wire constituting the antenna according to the invention.

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

Figure 10 is a section along line X-X of Figure 9.

In the context of a preferred but not exclusive application, the invention provides for integrating a resonant antenna 1, of small thickness, into an identification bib 2 for sports competition. The bib forming the support 2 of the antenna can be made of any suitable material and preferably of flexible material, such as for example a nonwoven material, a film of synthetic material or even of fabric. Thus, according to the example illustrated, the antenna 1 comprises three turns, of generally rectangular shape, 3, 4, 5. Of course, according to the invention, the antenna resonant 1 could only include a single turn. According to the example illustrated, the antenna 1 is intended to constitute a supply and transmission antenna for a transponder chip 7 also fixed on the support 2. Such a chip 7 does not come within the scope of the present invention and is widely known to those skilled in the art. As an indication, it may be recalled that such transponder chips operate on a frequency of approximately 13.56 Mz and are marketed by Companies such as PHILIPS or INSIDE, under different trade names. Of course, the resonant antenna according to the invention can be used at other frequencies. The resonant antenna 1, within the meaning of the invention, can be qualified as thin in so far as the surface 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.

In accordance with an essential characteristic of the invention, the maintenance of the conductive wire 10, constituting the antenna 1, is carried out by using means 11 for mechanically maintaining the wire 10 on the support constituting the bib 2.

According to the example illustrated, the bib 2 is made of a material, in a sheet, nonwoven, capable of being sewn. Thus, according to this example and as shown in FIG. 2, the conducting wire 10 is directly sewn onto the support 2. This sewing is carried out, according to a pattern corresponding to the shape of the antenna, by means of a sewing machine the bobbin thread of which consists of the conductive thread 10, while the needle thread 11 consists of a thread of any suitable material. The wire 11 then forms the means for immobilizing or mechanically holding the wire on its substrate. According to the example of FIG. 2, the tension applied to the conductive threads is substantially equal to that applied to the textile thread, so that the latter have a substantially symmetrical shape. On the other hand, in the example of FIG. 3, the tension applied to the conductive thread 10, during its sewing, is greater than that applied to the textile thread 11, so that the conductive thread 10 is not deformed by the textile thread 11.

According to the invention, the immobilization, on the support 2, of the conducting wire 10 constituting the loops or turns of the antenna 1, is not necessarily carried out by direct sewing of the conducting wire 10. Thus, FIGS. 4 and 5 illustrate another method of attachment, by sewing, according to which the conducting wire 10 is held by means of a seam in a zigzag 15, the different points or stitches 16 of which extend on either side of the conductive wire 10 which then constitutes the pass wire. This zigzag stitching 15 is carried out with two threads 17, 18 textile or synthetic. Such maintenance by overcasting also makes it possible, depending on the stitching pitch selected, to produce a sort of sheath made up of wires 17, 18 around the conductive wire 10. Furthermore, the method of holding the antenna wire, on the support 2, according to the invention, by sewing, has the advantage of not altering the mechanical qualities of the support, in particular the flexibility of the latter. In addition, the antenna wire can be sewn with a simple and inexpensive sewing machine, so that it is possible to obtain products such as, for example, single-use bibs.

According to another embodiment more particularly illustrated in FIG. 6, the conducting wire 10 is immobilized or maintained by means of staples 20 arranged astride the conducting wire 10. Such staples can be of any suitable nature. Similarly, instead of staples, it could be envisaged to make bridges or punctual ligatures around the conductive wire 10, through the support 2.

According to the example illustrated in FIG. 7, the conductive wire 10 is held on the support 2 in a sheath 25 attached to said support 2. The edges 26 of the sheath 25 are fixed to the support by any suitable means such as for example by heat sealing or ultrasonic welding. It could also be envisaged to sew the sheath 25 on the support 2.

FIG. 8 illustrates yet another mode of immobilization of the wire 10 on the support 2. According to this embodiment, there is arranged, in the support 2, a series of passages 30 passing through in a pattern reproducing the general 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 and the other faces of the support 2.

Figures 9 and 10 illustrate another form of mechanical support of the conductor 10, by means of bridges 35 made in the support

2 and defined by two parallel slots 36 in which the conductor 10 has passed successively, so that it is then immobilized by pinching.

It should be noted that the methods of maintenance provided by the invention have the advantage of not altering the flexibility qualities of the support used. In addition, according to the examples illustrated, the support used has a substantially planar shape. However, as part of example but not exclusively, of holding by sewing, it is possible to integrate or make the antenna for transponder directly on a textile element of a garment, for example, a sleeve or other. In the same way, the antenna can be produced in car seat or furniture covers or any other support such as, for example, postal bags or bags for packaging products for which it is necessary to ensure traceability.

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 can be used alone or in combination with a passive component to constitute a simple resonant antenna of the type used in detection in anti-theft systems for example.

Of course, the invention is not limited to the examples described above and various modifications can be made without departing from its scope.

Claims

1. A thin resonant detection or identification antenna, of the type comprising at least one turn (3) constituted by 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 punctual and produced by mechanical means (11), which ensure positive transverse immobilization of the wire relative to the support.

2. Antenna according to claim 1, characterized in that: - the support (2) has a series of through passages (30) for immobilizing the wire (10), arranged in a pattern corresponding to the shape of the turn,

- And the conductive wire (10) passes through the passages (30) being located alternately on one of the two faces of the support (2).

3. Antenna according to claim 1, characterized in that the conductive wire (10) is fixed on one side of the support with attached mechanical fixing means (11, 20, 17, 18).

4. Antenna according to one of claims 1 to 3, characterized in that the conductive wire (10) is fixed by bridges (35) or the like, integral with the support and pressing the conductive wire against the support.

5. Antenna according to claim 3, characterized in that the conductive fi is fixed by staples (20) or the like on the support.

6. Antenna according to claim 3, characterized in that the conductive fi (10) is sewn on the support.

7. Antenna according to claim 6, characterized in that the conductive fi (10) constitutes one of the two threads of a two-threaded seam.

8. Antenna according to claim 6, characterized in that the conductive fi is immobilized on the support by a zigzag seam (15) whose points (16) are arranged alternately on either side of the conductive fi (10).

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

10. Antenna according to one of claims 1 to 9, characterized in that the conductive wire (10) is placed in relation to a transponder electronic chip (7).

11. Antenna according to claim 10, characterized in that the conductive wire (10) is electrically connected to the electronic chip (7).

12. Antenna according to one of claims 1 to 11, characterized in that the support (2) comprises a textile sheet.

13. Antenna according to one of claims 1 to 12, characterized in that the support (2) forms part of a garment.

14. Antenna according to one of claims 1 to 12, characterized in that the support (2) forms at least part of an identification bib.

15. An antenna according to one of claims 1 to 14, characterized in that the support 2 is substantially planar or in sheet form.

16. Method for manufacturing a thin antenna for transponder on a support, of the type consisting in producing at least one turn consisting of at least one electrically conductive wire attached to the support and fixed on the latter, characterized in that '' it consists in securing the wire (10) on the support (2) with fixing means (11, 17, 18, 20, 25) which are attached to the support and which ensure at least punctual fixing of the wire (10) with positive transverse immobilization of the wire relative to the support.

17. The manufacturing method according to claim 16, characterized in that it consists in sewing the conductive wire (10) on the support (2).