Abstract:
The invention concerns a method of manufacturing a module intended to create a portable object with chip and antenna. The portable object comprises an antenna and a chip placed on an insulating substrate. The antenna comprises a plurality of turns. The method comprises a first step in which an insulating substrate with at least one side is provided. The method is characterised in that it further comprises a second step in which an individual housing opening in the said side is made for each of the said turns and a third step in which said antenna comprising a plurality of turns is made by placing a conducting material in each individual housing.

Description:
FIELD OF THE INVENTION 
   This invention concerns a method of manufacturing a module intended to create a portable object with chip and antenna including an antenna and a chip placed on an insulating substrate, a method of manufacturing a batch of n modules for portable objects with chip and antenna, a method of creating a portable object with chip and antenna, and a module intended to create a portable object with chip and antenna, and a portable object with chip and antenna. 
   Such portable objects may, in particular, be cards or phone cards, but also security labels or tags. 
   Such cards with chip and antenna are intended to load or download information by radio transmission of data between an antenna placed in the card body and a fixed transmitter/receiver located nearby. Such labels are, for example, intended to be affixed to products on sale to prevent theft. 
   BACKGROUND OF THE INVENTION 
   Methods of manufacturing such portable objects, especially cards, are known, for example in document U.S. Pat. No. 6,088,230, in which the antenna, consisting of a conducting wire, is first connected by one end to a contact on a chip placed on a substrate, then placed on the substrate with a wire guide and insertion means which are moved bi-axially across the surface of the substrate (along X and Y axes). When the antenna follows a meandering path, connection points are necessary at each change of direction. 
   To make these connection points, the insertion means must be lowered along a Z-axis and the conducting wire is temporarily pressed against the surface of the substrate and then pressed and thermally welded in the substrate. Lastly, the second end is connected to another contact of the chip, and the substrate and its components can then be covered by a protective layer. 
   The steps involved in producing a card with chip and antenna are difficult, especially when the antenna is not straight. 
   In addition, the antenna is not held in place before being covered with the protective layer, making it impossible to guarantee its position. 
   The European patent application published under number EP 0 841 634 concerns a method of manufacturing an integrated circuit card comprising an antenna comprising at least one turn in which a unique housing is made to contain said antenna. 
   The U.S. Patent published under U.S. Pat. No. 6,021,949 concerns a gaming token comprising an electronic identification element and an antenna. The antenna may comprise a plurality of turns which are placed in a unique housing. 
   By placing an antenna comprising a plurality of turns in a unique housing there is some disadvantages. During, for example, an injection step following a positioning step in which the antenna is placed in the unique housing, the position of the turns can namely vary, thus modifying the geometry of the antenna. By modifying the geometry of the antenna, there is a risk that the operating frequency of the portable object can be less precisely defined. So the portable object obtained by such a method can be less reliable. 
   SUMMARY OF THE INVENTION 
   One purpose of the invention is to propose a method which enable to obtain a more reliable portable object. 
   According to an aspect of the invention, a method of manufacturing a module intended to create a portable object with chip and antenna. The portable object comprises an antenna and a chip placed on an insulating substrate. The antenna comprises a plurality of turns. The method comprises a first step in which an insulating substrate with at least one side is provided. The method is characterised in that it further comprises:
         a second step in which an individual housing opening in the said side is made for each of the said turns;   a third step in which said antenna comprising a plurality of turns is made by placing a conducting material in each individual housing.       

   By first making a plurality of individual housings and then by placing each turn of the antenna in a different individual housing, the insulation between the different turns is better. Furthermore the geometry of the antenna is more precisely defined. In particular there is a little risk that the different turns moves during the manufacturing process. The cross-section of the turns, their geometric shape, the distance between them is for example more precisely defined. By thus defining more precisely the geometry of the antenna, the wavelength and operating frequency of the portable object can be more precisely defined in a specific range. This range corresponds thus better to that of the fixed ad hoc transmitters/receivers. So the method according to the invention enables to obtain portable object which are more reliable. 
   Advantageously, the individual housing can be produced by machining or by laser. 
   Advantageously, the substrate includes a thermoplastic and the said housing can then be made by hot pressing or moulding. 
   These modes of realisation of the housing are easy to implement and provide in particular an easy way of making any shape of housing, which means in addition that numerous possibilities are available concerning the type of antenna. 
   In particular the type of material employed for the antenna contribute to define a precise wavelength and operating frequency in the same range as that of the fixed ad hoc transmitters/receivers. Generally the antenna consists of a conducting material, which in this case can be made from a conducting wire or a conducting paste, depending on the chosen housing. 
   The turns forming the antenna may have a circular cross-section when a conducting wire is used, for example, and may be wound in various geometries. 
   Advantageously, the said antenna and the said connections are realised simultaneously. 
   The connections between the antenna and the chip can be made by direct contacts, each end of the antenna then being physically connected according to known techniques to a respective connector on the chip. The connections can also be made without contact, in this case the chip includes an inductor and the antenna includes an induction coil which interacts with the chip inductor. 
   An other object of this invention is to propose a method of manufacturing a batch of n modules for portable objects with chip and antenna each comprising an antenna comprising a plurality of turns and a chip placed on an insulating substrate. 
   This objective is reached due to the fact that a plate is provided on which n areas are defined each including an insulating substrate each of which comprises at least one side, that a plurality of individual housing opening in each of the said sides is made, said individual housings intended to contain separately each turn of an antenna and, that an antenna comprising a plurality of turns is made by placing a conducting material in each of the said individual housings. 
   This method can be used to produce the modules in medium or even long series production runs. All the housings can, for example, be produced in one step, then all the antennas are made, etc. In particular, this enables the various steps of the method to be carried out on different stations. 
   An other object of this invention is to improve a method of creating a portable object with chip and antenna. 
   This objective is achieved due to the fact that said portable object with chip and antenna is made from a module comprising a chip, an antenna comprising a plurality of turns, a substrate in which a plurality of individual housings is made to individually contain the turns. 
   When the substrate includes advantageously a thermoplastic, at least one layer of thermoplastic can be placed on the said module and the assembly formed by the said module and the said layer of thermoplastic can be hot rolled or the said substrate can be placed in a mould and a thermoplastic material can be injected in the said mould. 
   These two techniques can be used to produce by polymerisation strong bonds between the thermoplastic substrate and the thermoplastic material added to create the portable object with chip and antenna. Thus, after treatment, the substrate is completely buried in the body of the portable object and its physical shape is no longer visible. The rolling or moulding temperatures are low enough to avoid damage to the module, in particular to the electronic components it includes. 
   Advantageously, an additional form forming a cover can also be placed over the individual housings of the said module to create the portable object with chip and antenna. 
   This method is especially useful when using a batch of n modules as mentioned above and a single additional form is placed over the entire plate to close each housing. 
   With the present invention it is still possible to propose a method for creating simultaneously n portable objects with chip and antenna each including an antenna and a chip. This is possible due to the fact that the said portable object with chip and antenna is made from the batch of n modules obtained according to the above-mentioned method. 
   Advantageously, the n portable objects with chip and antenna can be produced using methods similar to those described previously. In particular, they can be obtained by moulding or hot rolling, when the plate includes advantageously a thermoplastic or with a cover. The assembly so formed, including the plate and the modules, is then cut into n portable objects with chip and antenna. 
   An other object of this invention is to improve a module intended to create a portable object with chip and antenna comprising an antenna and a chip placed on an insulating substrate, said antenna comprising a plurality of turns. 
   This object is reached due to the fact that the module comprises an insulating substrate comprising at least one side, a plurality of individual housings opening in said side, that each individual housing comprises a turn of said antenna, said turn being made of a conducting material. 
   These modules form the main part of the body of a portable object with chip and antenna in which they are fitted simply, for example, according to one of the previously described methods. 
   These modules can be obtained according to any of the above-mentioned methods. In particular, they can be made individually or in a plate cut afterwards. 
   An other object of this invention is to improve a portable object with chip and antenna comprising a chip and an antenna. 
   This object is reached due to the fact that the portable object with chip and antenna comprises a module obtained according to any of the previously described methods. 
   The invention will be clearly understood and its advantages will appear on reading the detailed description below, of modes of realisation represented as non-limiting examples. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The description refers to the attached drawings, on which: 
       FIG. 1  is a plan view of a substrate, 
       FIG. 2  is a plan view of a module including a substrate, an antenna and chip, 
       FIGS. 3A and 3B , are cross-sections according to line III—III of  FIG. 2  each illustrating a variant of the module, 
       FIG. 4  is a plan view of a plate including several modules, 
       FIG. 5  is a cross-section of the module of  FIG. 3A  placed in a mould, 
       FIG. 6  is a cross-section of a portable object, in particular a card with chip and antenna, 
       FIG. 7  is a cross-section of the module of  FIG. 3B  ready for hot rolling, and 
       FIG. 8  is a cross-section of the module on which a cover is placed. 
   

   DETAILED DESCRIPTION 
     FIG. 1  shows a substrate  10 , preferably of thermoplastic in which, on one of the sides  10 ′, individual open housings  12  has been produced intended to contain an antenna made from conducting material not represented. These housings  12  can be obtained, for example, by machining, laser or moulding. The substrate  10  may also include a housing intended to contain a chip. 
     FIG. 2  illustrates a module  24  including the substrate  10  on which a chip  18  has been placed and an antenna  20  which has been placed in the individual open housings  12 . 
   The connections between the antenna  20  and the chip  18  may occur by induction when the antenna  20  includes a coil and the chip  18  includes an inductor or by direct contacts.  FIG. 2  shows the antenna  20  which includes a first end  20 ′ connected to a first contact  18 ′ on the chip  18  and a second end  20 ″ connected to a second contact  18 ″. Since the mode of realisation of these connections  18 ′,  20 ′,  18 ″,  20 ″ by direct contacts is known, it is not described in this invention. Advantageously, means  22  are used to hold the antenna  20  in the housing  12 . These means  22  may be adhesive material or a special coating which is applied in the individual housings to make sure that the antenna  20  fitted afterwards is held firmly. 
   The antenna  20  may be obtained in several ways. In particular, it may be formed from a conducting wire  20   a , as shown on  FIG. 3A . The individual housings  12  thus avoid any short circuiting by contact between the various turns  14  of the antenna  20   a . The geometry of the antenna is also more precisely defined. In particular the distance between the different turns is more precisely defined. The cross-section of the individual housings  12   a  is preferably semi-circular. 
   The antenna  20  can also be made with a filling conducting resin  20   c .  FIG. 3B  shows an example of an individual housing  12   c  in which a filling conducting resin  20   c  has been applied. After polymerisation, the conducting resin  20   c  forms a solid conducting material similar to the conducting wire  20   a.    
   When the substrate  10  includes a chip  18  and an antenna  20  fitted in individual housings  12 , it will be referred to as a module  24 . This module  24  is then ready to be used to create a portable object, especially a card with chip and antenna. Preferably, apart from its thickness, the dimensions of the module  24  are similar to those of the card with chip and antenna for which it is intended (54×85 mm2 for a standard card). 
   When the module  24  is used to form another type of card, for example SIMM, care must be taken to place the antenna  20  and the chip  18  in the detachable area of the card support (approximately 15×25 mm2 for the standard SIMM cards) which is placed in the device for which it is intended (mobile telephone for example). 
   Generally in fact, the module  24  is placed in the useful area of the portable object which can be detached from a larger support intended, for example, to simplify its packaging and protect it before use. For the remainder of the description, we will concentrate on the special case of cards with chip and antenna. 
   The module  24  can be obtained in two different ways. 
   Firstly, the modules  24  can be produced individually, by placing a chip  18  on a substrate  10  in which individual housings  12  has been made (by machining, laser, moulding, hot pressing, etc.) and in which an antenna  20  of the above-mentioned type is placed. 
   Secondly, a batch  24 ′ of n modules  24  can be produced simultaneously on a plate  26  on which areas  28  are defined. In each of these areas  28 , individual open housings  12  are made according to any of the above-mentioned techniques, in which an antenna  20  comprising a plurality of turns and a chip  18  are placed. Each module  24  obtained can then be cut out giving the same shape as that obtained using the individual method or the plate  26  including the n modules  24  can be implemented in its entirety in the form of a batch of n cards with chip and antenna before being cut to the particular format of the card. 
   Several methods are available to integrate the module  24  In the body of a smartcard. These methods are the same when using a plate  26  including n modules  24 , to produce simultaneously a batch of n cards with chip and antenna. 
   When the module  24  used is a thermoplastic, to produce a card with chip and antenna, the module  24  can be placed in the bottom  30  of a mould  32  preferably made from two parts  32   a  and  32   b , the part  32   a  supporting for example the module  24 , as shown on  FIG. 5 . Thermoplastic material can then be injected through an opening  34  provided for this purpose in the part  32   b . The thermoplastic forming the substrate  10  will react with the thermoplastic material added to form strong bonds by polymerisation. After demoulding, a card with chip and antenna  36  is obtained, as shown on  FIG. 6 , in which the substrate  10  is no longer visible, since it is completely fused with the added thermoplastic material. The chip  18  and the antenna  20  are completely buried in the body of the smartcard  36 . 
   When the module used is a thermoplastic, the card with chip and antenna  36  can also be produced by hot rolling. In this case, as shown on  FIG. 7 , a thermoplastic sheet  38  is placed over the side  10 ′ of the substrate  10  including the antenna  20  and the chip  18  and the assembly is hot rolled between known rollers, not shown, so as to form the card with chip and antenna  36  in which the substrate  10  is no longer visible. Preferably, two thermoplastic sheets  38  and  40  are used between which the module  24  is placed. 
     FIG. 8  shows another method of producing cards with chip and antenna. The individual housings are closed by placing on the side  10 ′ of the substrate  10 , wholly or partially, an additional form  42  which has raised sections  44  formed on one of these sides intended to enter the individual housings  12   b . The additional form  42  constitutes a cover  42  which is held on the side  10 ′ by adhesive, thermal, mechanical means, etc., not described, so as to form a card with chip and antenna. 
   The methods employed to manufacture a card with chip and antenna  36  using the above-mentioned methods also apply to the manufacture of batches of n cards with chip and antenna  36 . In fact, the substrate  10  is replaced by the plate  26  including n modules  24  and the same steps as those described, specific to each method, are applied. Thus, an assembly is obtained from the plate  26  including a batch of cards with chip and antenna, which is simply cut out to obtain n cards with chip and antenna  36 . 
   As for the substrate  10 , when proceeding by moulding or hot rolling, the plate  26  is no longer visible in the assembly of cards with chip and antenna, since it is completely buried in the thermoplastic material added. Although both of these methods can be used with a plate  26  including several modules  24 , it is preferable to first cut out n modules  24  and to produce and realise n cards with chip and antenna  36  individually. The method with cover  42  is as easy to implement, whether for a module  24  or a plate  26  including the batch  24 ′ of n modules  24 .