FR2780338A1 - METHOD FOR MANUFACTURING CHIP CARDS PROVIDED WITH SURFACE FILMS - Google Patents

Abstract

The invention relates to a method of manufacturing a card comprising, on the one hand, a card body (2) comprising an outer layer (4, 7) coated with a surface film (8, 9). According to the invention, this method is characterized in that it comprises the following steps according to which: the surface film (8, 9) is pierced with through holes (14); - The outer layer (4, 7) is coated with said surface film (8, 9) pierced with holes (14); and- hot-rolled an assembly comprising the surface film (8, 9) and the outer layer (4, 7) coated with said film (8, 9). The invention applies in particular to the manufacture of contactless smart cards.

Description

METHOD FOR MANUFACTURING CHIP CARDS

PROVIDED WITH SURFACE FILMS

  The invention relates to a method of manufacturing smart cards provided with surface films usually designated by the English term "overlays". The function of smart cards is to identify their holder and to secure data relating, in particular, to electronic transactions carried out by said holder, or else, to rights to which

the latter can claim.

  These are portable objects comprising, on the one hand, a card body and, on the other hand, an electronic component with integrated circuit or chip. The card body is plastic and consists of one or more layers. The outer layers of said body are advantageously coated with generally transparent surface films. Thanks to these films, the card has a beautiful shine appearance and the printed patterns of the

  card bodies are protected from damage they may suffer.

  The electronic component is a silicon chip on which a circuit is integrated which defines functional assemblies, such as memory assemblies, for example of the RAM, ROM or EEPROM type, or, in the case of so-called microprocessor cards, a unit.

central processing unit (CPU).

  The electronic component is incorporated into the body of the card. To this end, it is sometimes previously integrated into the electronic module.

  transferred to a cavity in the card body.

  The electronic component is moreover capable of being connected to the terminals of an antenna. In this case, the card has a contactless operating mode and the data it exchanges with the outside environment are capable of being transmitted by electromagnetic coupling between the antenna of the card and the antenna of an associated reader. . In the case where the electronic component is not connected to the terminals of an antenna, the data transmission

  on the other hand necessarily takes place by means of electrical contacts.

  Different processes are known for manufacturing smart cards.

  Some methods propose hot colamination of an assembly comprising the different layers intended to form the card body, the surface films and the chip possibly integrated within an electronic module and / or connected to the terminals of an antenna. To this end, pressure forces are applied to the above-mentioned assembly so that, at a temperature of the order of

   C, the layers and films are welded.

  However, these methods have certain disadvantages due to the fact that, during colamination, air bubbles are sometimes

  trapped between the surface films and the layers they cover.

  This results in certain apparent defects on the surface of the card body and, in particular, the formation of blisters or areas of contrasting brightness. Considering the above, an objective problem which the invention proposes to solve is to avoid apparent defects on the surface of the

  cards with surface films.

  The solution of the invention to this problem relates to a method of manufacturing a card comprising a card body, said card body comprising an outer layer coated with a surface film characterized in that it comprises the steps following which the surface film is drilled through holes; the outer layer (4, 7) is coated with said surface film pierced with holes; and a set comprising said film is hot-rolled

  surface and the outer layer coated with said film.

  Thus, the air bubbles trapped between the outer layer and the surface film escape through the holes. The manufactured card does not have

  then no appearance defects due to said air bubbles.

  Advantageously, the holes have an average diameter of between 0.2 and 1.4 mm, in particular of the order of 0.8 mm. Thus, the holes heal during the colamination step and the

  finished card has no holes.

  Advantageously, 0.1 to 2.5% of the surface of the film, preferably of the order of 0.5% of this surface, is pierced with

1 0 holes.

  Thus, the shrinkages due to the polymerization of the film and the scarring are not sufficient to cause defects in the appearance of the card. The invention will be better understood on reading the nonlimiting description of the examples of implementation which will follow, written with reference to the attached drawings, in which: FIG. 1A shows, in cross section, a smart card with contacts; FIG. 1B shows, in cross section, a contactless smart card; FIG. 2 illustrates, in cross section, a step of colamination of a contactless card according to the method of the invention; FIG. 3A shows, in cross section and in enlarged view, a surface film intended for the implementation of the method of the invention; FIG. 3B shows, in cross section and in enlarged view, a surface film of a card obtained according to the method of the invention; and FIG. 4 shows, in cross section, the manner in which the surface films are fixed in the assembly intended for colamination

according to the method of the invention.

  The method of the invention is intended for the manufacture of smart cards 1 of the type of those shown in FIGS. 1A and 1B. Such smart cards 1 are standardized objects as defined in particular in ISO standards 7810, 7816 and 14443, the content of which is integrated into the present description, by reference citation. They are in particular in the form of rectangular and portable rectangular parallelepipeds whose dimensions are of the order of 85 mm in length, 54 mm in width and

760 mm thick.

  Smart cards 1 consist of a card body 2 within

  of which an electronic component is integrated 3.

  The card body 2 consists of one or more layers 4, 5, 6, 7, thermoplastic or thermosetting, for example, consisting of acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC), polyethylene terephthalate ( PET), polycarbonate (PC) or

polymethylmethacrylate (PMMA).

  The outer layer or layers 4, 7 of said card body 2 are generally printed. They are also coated with films 8, 9 of

  thin transparent surfaces, generally around 50> rm.

  As for layers 4, 5, 6, 7 of the card body 2, the films 8, 9 are thermoplastic or thermosetting, for example made of acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC), polyethylene terephthalate (PET), polycarbonate (PC) or polymethylmethacrylate (PMMA). These films 8, 9 can be

transparent or printed.

  The electronic component 3 is a chip possibly integrated within a module 10 and possibly connected to the terminals of a

antenna 11 of card 1.

  The contact card shown in FIG. 1A comprises a body 2 of

card and module 10.

  The card body 2 has four plastic layers 4, 5, 6, 7, two outer layers 4, 7 and two sublayers 5, 6, the two layers

  4, 7 external being each coated with a film 8, 9 of PVC surface.

  Layers 4, 5, 6, 7 are thermoplastic from PVC or PC.

  The module 10 is incorporated into the card body 2. It comprises an integrated circuit chip 3, of which contact pads are connected, by conductive wires 12, to contact pads 13 flush with the

body surface 2.

  The contactless card shown in FIG. 1B has a body 2

card and chip 3.

  The card body 2 has four plastic layers 4, 5, 6, 7, two outer layers 4, 7 and two sublayers 5, 6 as well as two films 8, 9. The layers 4, 7 are thermoplastic layers of PC with a thickness of the order of 150 mm. The sublayer 5 is a thermoplastic layer of PVC with a thickness of the order of 190 μm and the sublayer 6 is a thermoplastic layer of PVC with a thickness of the order of 300 gm. Films 8, 9, which cover layers 4, 7

  are transparent and have a thickness of the order of 50 μm.

  The chip 3 is connected, by its active face provided with protuberances, to terminals of the antenna 11 screen-printed on the surface

  of the sublayer 5. It is embedded in the sublayer 6.

  For the manufacture of a card according to the method of the invention and, in particular, for the manufacture of the contactless card shown in the

  FIG. 1B, we proceed in different stages.

  In a preliminary step, the films 8, 9 are pierced with through holes 14. As is more particularly shown in the figure

  3A, these holes 14 are substantially cylindrical of revolution.

  However, they can have the appearance of slots or more generally of any cuts. The average diameter of said holes 14, advantageously between 0.2 and 1.4 mm, is for example of the order of 0.8 mm. The average spacing between these holes 14, advantageously between 2 and 20 mm, is for example of the order of 10 mm. Also, 0.1 to 2.5%, in particular 0.5% of the surface of the films 8, 9 is pierced with holes 14. It will be noted that the means intended for drilling the holes 14 may consist of a roller provided with needles of the desired diameter, this roller being passed over strips of

  films for large-scale drilling.

  In another preliminary step, the chip 3 provided with protuberances 15 is transferred to the sublayer 5 on the surface of which the antenna 11 has been screen-printed or engraved. The chip 3, fixed to the sublayer 5 is then electrically connected to the terminals of said

antenna 11.

  Said preliminary steps having been carried out, the outer layer 4 is superimposed, the sublayer 5 carrying the chip 3, the sublayer 6, the outer layer 7 and the surface films 8, 9 so as to form a superimposed assembly that we place between plates 16, 17 parallel

  a pressing device (Figure 2).

  Because, in particular, of the thickness of the chip 3, the layers 4, 5, 6, 7 and films 8, 9 of the assembly placed in the pressing device are not strictly parallel. Air pockets therefore exist in the superimposed assembly and, in particular, between the films 8, 9 and the outer layers 4, 7 which do not adhere to said films 8, 9 at this stage

of the process of the invention.

  However, in a colamination step during which the plates 16, 17 of the pressing device are brought close to each other and brought, for example in an oven, to a temperature of the order of 120 C, the layers 4, 5, 6, 7 and films 8, 9 are welded to each other, the air pockets emptying through the through holes 14

  wide enough to allow air to escape.

  Under the effect of pressure and heat, the holes 14 heal, that is to say, fill up. This scarring is allowed because of a sufficiently small diameter of the holes 14. The card 1, then obtained after having been removed from the device

  pressing, has no appearance defect.

  In practice, for the mass production of smart cards, the colaminated assemblies have much larger dimensions than those of the cards and comprise several chips 3 (see FIGS. 2 and 4). Thus, it is possible to make several cards at the same time, after a step

  complementary cutting of colaminated assemblies.

  In this regard, it should be noted that the films 8, 9, which previously had to be stretched over the surface of the assemblies so as to minimize the formation of air pockets, are not necessarily stretched in the implementation of the invention. It is therefore possible to cover the layers to be laminated with a single film 8, 9 fixed, as shown in Figure 4, at the same end of the assembly. This unique film 8, 9 then covers, like a book cover,

the set of layers 4, 5, 6, 7.

  Of course, the method of the invention, described above with regard to the manufacture of a contactless card, applies to the manufacture of contact cards. Indeed, air bubbles are always present

  between layers and films before colamination.

  The method of the invention also applies to the manufacture of cards by colamination in the case where the modules or else the chips are not present in the colaminated assembly, but are carried over

in a later step.

Claims (6)

  1 - Method for manufacturing a card (1) comprising a card body (2), said card body (2) comprising an external layer (4, 7) coated with a surface film (8, 9), characterized in that it comprises the following stages according to which: - the surface film (8, 9) is drilled with through holes (14); - The outer layer (4, 7) is coated with said surface film (8, 9) pierced with holes (14); and - a set comprising the surface film is hot-rolled   (8, 9) and the outer layer (4, 7) coated with said film (8, 9).   2 - Method according to claim 1, characterized in that the card   further comprises an electronic component (3) with integrated circuit.   3 - Method according to claim 2, characterized in that the hot-rolled assembly further comprises the component electronic (3).   4 - Method according to one of claims 2 or 3, characterized in that   that the electronic component (3) is connected to terminals of a   antenna (11) for contactless operation of the card (1).   - Method according to one of the preceding claims, characterized   in that the holes (14) have an average diameter of between 0.2 and 1.4 mm, in particular of the order of 0.8 mm.   6 - Method according to one of the preceding claims, characterized   in that the mean distance between the holes (14) is between 2 and 20 mm, in particular of the order of 10 mm.   7 - Method according to one of the preceding claims, characterized   in that 0.1 to 2.5%, especially 0.5% of the film surface is pierced with holes (14).