FR3061406A1 - PROCESS FOR PRODUCING A CENTRAL LAYER OF A MICROCIRCUIT CARD - Google Patents

Abstract

In order to form a central microcircuit card layer 21 comprising an electronic module formed of a support 25 carrying at least one electronic component, this module is formed, on the one hand, and, on the other hand, a frame having an opening that can receive this module by presenting a few projecting zones 14 of its inner contour which have a reduced thickness, the module is fixed to these areas of reduced thickness and the space between this module and the frame is filled with a resin. This frame is formed by joining a first partial frame 11 comprising these zones 14 and whose thickness is that of these zones, with a second frame 15 surrounding these areas in particular protruding.

Description

© Holder (s): OBERTHUR TECHNOLOGIES Limited company.

o Extension request (s):

(® Agent (s): SANTARELLI.

(54) METHOD FOR MANUFACTURING A CENTRAL LAYER OF A MICROCIRCUIT CARD.

FR 3061406 - A1 (57) f _or forming a core layer 21 of a microcircuit card comprising an electronic module formed by a support 25 carrying at least one electronic component is formed, on the one hand, this module and, on the other hand, a frame having an opening capable of receiving this module by presenting a few protruding zones 14 of its internal contour which have a reduced thickness, the module is fixed to these zones of reduced thickness and a resin is filled in. space between this module and the frame. This frame is formed by securing a first partial frame 11 comprising these areas 14 and the thickness of which is that of these areas, with a second frame 15 in particular surrounding these projecting areas.

The invention relates to a method of manufacturing a body intended to constitute a central layer of a card and incorporating at least one electronic component (the term "inlay" or "prelam" is sometimes spoken).

Since the technique of forming a card body provided with a cavity and inserting a small module in the cavity, various other techniques have been developed, including in particular that of producing a printed circuit support provided on at least one of its faces of electronic components and of fixing such a printed circuit support in a frame surrounding an opening receiving this printed circuit and defining the thickness of the future central layer of smart card.

Such a technique is notably described in documents WO - 2007/147727 and WO - 2007/147729.

To ensure good fixing of the printed circuit support provided with its components in the frame, it is thus conventional to give the frame an internal contour capable of surrounding the external contour of the printed circuit except in a few zones of this internal contour which come in protruding towards the outer contour, applying pressure to these protruding areas making it possible to reduce the thickness thereof by a distance at least equal to the thickness of the printed circuit support on which the components are mounted, then fix this printed circuit support to the frame using an adhesive located between these areas of reduced thickness and peripheral areas of the printed circuit.

In fact, the fact that the internal contour protrudes from the external contour simply means that there are, between these contours, overlapping zones perpendicular to the plane of their largest dimensions; this is how it covers in particular the case where the external contour has a simple shape, such as a rectangle, and where the internal contour has a similar shape, only slightly larger, except that it has protuberances towards the interior of the opening, or even the case where the internal contour has a simple shape and protrusions are formed on the contour of the printed circuit; there may be a combination of these two cases; the protrusions may be more or less significant, which may in particular be an elongated strip along one side of the external contour, or of the internal coast. However, a simple case consists in providing the internal outline of the frame with a small number (for example between two and five) small triangular growths.

In practice, we start by depositing glue (or any other adhesive material allowing a later fixing between the printed circuit and the frame) on an area of a starting plate in which we cut the internal opening of the frame, according to the internal contour comprising the zones which must project from the external contour of the printed circuit.

We continue with a step consisting in locally crushing the frame, only these projecting areas so as to reduce the thickness.

The electronic module consisting of the printed circuit support provided with its components is then put in place (unless it has already been put in place and the crushing has been caused by pressure from peripheral zones of this printed circuit support ), and we activate the glue (or the adhesive material used).

The spaces remaining between the printed microcircuit and the frame are then filled with an appropriate resin until a body of constant thickness is obtained; this step can be followed by a lamination step, between two rollers, to guarantee both the consistency of the thickness of the central card layer and the good cohesion of the various components of this central card layer.

There may then be stages of covering the card (fixing of cover and / or protection layers, or formation of magnetic tracks, or generation of visual effects, in particular) to form a complete smart card.

However, this technique has certain drawbacks:

- Cutting by stamping the internal opening of the frame can, if the tool becomes worn, leave material threads remaining, the removal of which involves an additional deburring step (which we nevertheless seek to avoid for reasons of production rate)

- The final thickness of the crushed areas depends on the initial thickness, which can vary from one plate to another, due to the manufacturing tolerances on this thickness,

- The crushing of the protruding areas can cause the material to creep laterally until local thicknesses appear, along the internal outline of the frame

- The material, once crushed, can "re-inflate" or regain a little of its initial thickness (this can in particular be the case with PVC) when we cannot really control this phenomenon.

These drawbacks can induce defects, such as surface irregularities of the central layer of the final card or internal stresses which can disturb the mechanical strength of this layer (in the case of local excess thicknesses), or defects in connection between the support to printed circuit and the frame (when the crushing is slightly higher than that which is necessary).

There is therefore a need to be able to better control the reproducibility of the formation of protruding areas of reduced thickness.

To this end, the invention provides a method of manufacturing at least one central layer of a microcircuit card, this central layer comprising an electronic module formed by a printed circuit support provided on at least one of its faces with at least an electronic component according to which:

* on the one hand, this electronic module is formed with an external contour determined by the external contour of the printed circuit and, on the other hand, a frame of constant thickness having, inside a future external contour of card, an opening delimited by an internal contour capable of surrounding the external contour of the printed circuit except in a few zones of this internal contour which project towards the inside of the opening, these few zones having a reduced thickness compared to the constant thickness of this frame outside these areas, * these areas of reduced thickness are fixed with respect to that of the frame to areas facing the periphery of the printed circuit support, and * we fill with a resin l space remaining between this electronic module and this frame so as to define a body having the thickness of this frame, characterized in that the frame is formed in two separate parts adapted to be superimposed s, namely a first partial frame having a first opening delimited by said internal contour of the frame and a thickness equal to said reduced thickness, and a second partial frame having a second opening delimited by a second internal contour surrounding the opening of the first frame partial as well as said projecting zones, these two separate parts then being joined, the cumulative thickness of the first and second partial frames thus joined determining the constant thickness of said frame.

Thanks to the invention, the reduced thickness of the projecting zones depends only on that of the first partial frame (it no longer depends on the training methods, by cutting in practice, on the opening of this first partial frame) and it there is no risk of local excess thickness in an area of reduced thickness; moreover, the delimitation of the outline of these projecting zones being made over a thickness less than the thickness of the complete frame, the risk of material threads is very reduced. Finally, it is no longer necessary to provide localized compression tools.

The cumulative thickness of the first and second partial frames thus assembled may be different from the sum of the thicknesses of the partial frames, and depend on the existence, or not, of a layer of adhesive between these frames and / or of a possible mechanical treatment (for example by passing between lamination rollers) provided to complete the joining step.

Preferably:

- The second internal contour of the second partial frame runs along the first internal contour of the first partial frame while bypassing the zones that this first internal contour of the first partial frame projects in relation to the external contour of the module; this amounts to reproducing precisely the usual geometry of the frames,

- The thickness of the first partial frame is chosen between 50% and 75% of that of the frame, which amounts to saying that the second frame has a thickness of 25% to 50% of the frame (to the thickness near a possible layer of adhesive between these partial frames), which amounts to saying that the invention makes it possible to avoid the consequences of a compression of at least 25% and being able to go up to 50%, one delimits the external contour a central smart card layer in said body so that it surrounds the internal contour of the frame; that is to say that we find in the central layer of a finished card at least part of the frame; the determination of the outer contour of the central layer can only take place at a later stage (several days or weeks after), when the central layer is used to make complete maps.

the electronic module is fixed to the zones of reduced thickness before joining the first and second partial frames, which amounts to taking advantage of the fact that the frame is in two parts (the fixing operation is simplified for reasons of access in the precise fixing zone, in particular), the resin is deposited on a reference surface before positioning the first partial frame on this same reference surface; thus the pressure, even limited, applied for the positioning of the first partial frame contributes to forcing the resin to fill all the interstices well, to secure the partial frames, a layer of filling resin is deposited on the first partial frame before there position the second partial frame; the fact that it is necessary to secure the two partial frames therefore does not imply implementing a product other than those which are available for the conventional process, defined in the abovementioned documents, the projecting zones have a triangle shape pointing towards inside the opening of the frame, which contributes to easily define areas for fixing to the electronic module, the projecting areas are in a number between 2 and 5, terminals included, which constitutes a good compromise simplicity / solidity (the more the number exceeds 3, the more there is a risk of hyperstatism), the first and second partial frames are part of plates each having the same number of openings, which allows collective production, the body obtained after the filling step with resin, forming a plurality of central layers of smart card, then being cut in due time, possibly on another production line, s elon said external card contours, in several individual cards the resin is thermosetting, for example of a two-component type; it can in particular be a resin forming a polyurethane, or polymerizing by thermal effect, or by application of UV, etc.

According to another aspect, the invention relates to a product obtained by the process, namely a central layer of microcircuit card comprising a microcircuit module formed by a printed circuit support provided on at least one of its faces with electronic components and a frame surrounding this module having a thickness at least equal to that of this electronic module by having an opening delimited by an internal contour capable of surrounding the external contour of the printed circuit support except in a few zones of this internal contour which come in protruding towards the inside of the opening, these few zones having a reduced thickness compared to the constant thickness of this frame outside these zones, the printed circuit support being fixed to these portions of reduced thickness and the space between this electronic module and this frame being filled with a resin, characterized in that this frame is formed by a first partial frame a having a first opening delimited by said internal contour of the frame and a thickness equal to said reduced thickness, and a second partial frame having a second opening delimited by a second internal contour surrounding the opening of the first partial frame as well as said projecting zones, the cumulative thickness of the first and second partial frames assembled together defining the constant thickness of said frame.

Objects, characteristics and advantages of the invention appear from the following description, given by way of nonlimiting illustrative example, with reference to the appended drawings in which:

FIG. 1 is an exploded perspective view of a frame according to the invention, intended for the manufacture of at least the central part of a microcircuit card,

- Figure 2 is a perspective view of a plate formed of a plurality of frames according to Figure 1,

FIG. 3 is a sectional view of a microcircuit card, in section along line A-A in FIG. 1,

- Figure 4 is a sectional view of an electronic module intended to be integrated into a frame according to Figure 1 to form a card according to Figure 3,

FIG. 5 is a sectional view of this electronic module assembled to a first part of the frame, according to a first step of manufacturing the card of FIG. 3,

- Figure 6 is a sectional view of this electronic module assembled to the frame, during a second manufacturing step and

- Figure 7 is a sectional view of this electronic module assembled to the frame, in a final step of manufacturing the card.

FIG. 1 shows, in exploded perspective, a frame 10 intended to surround an electronic module intended to form the electronic part of a future card; this frame comprises a first partial frame 11 surmounted by a second partial frame 12.

The first partial frame 11 has a constant thickness e1 and has an opening 13 delimited by a generally rectangular outline; however, this outline has a small number of areas projecting towards the inside of the opening, noted 14.

These projecting zones 14 are here in the form of a triangle, which corresponds to a geometric shape which is simple to define.

Their number is small in the sense that it is in practice between 2 and 5 (limits included); a number of 2 seems a minimum for the positioning that this partial frame is required to provide with respect to an electronic module intended to be fixed to this frame, while a number greater than 5 seems to no longer have any real utility for such positioning.

In the example shown, there are three projections 14, one of which is approximately in the middle of the side of the abovementioned rectangular shape, while the other two projections are arranged on the adjacent sides, close to the side without projections; but many variations are also possible.

The second partial frame 12 is intended, during the manufacture of a microcircuit card, or at least during the manufacture of an inlay (the term "prelam" is also used) intended to form the middle layer d '' such a card, to be superimposed on the first partial frame 11 and to be fixed to it by any suitable means, such as glue or any other adhesive material, or even by welding (taking advantage of the fact that, in practice, the constituent materials frames are fusible, allowing reciprocal welding by localized heat supply).

This second partial frame 12 has a constant thickness e2 and also includes an opening, denoted 15, delimited by a contour in practice similar to that of the opening 13, except that there are no projecting zones coming from cover the projections 14. This shape is therefore, here, exactly rectangular.

The outline of the opening 15 may be identical in dimensions to that of the opening 14 but may also have slightly larger dimensions, for example between 100% and 110% of those of the opening 14 (in the case shown here of a polygonal shape, some of the dimensions can be equal, therefore to 100%, of those of the opening 14). It is however preferable that the dimensions of the opening 15 is not too large vis-à-vis the opening 13 (there is no particular interest in that there remains a large space between the contour of the frame and the electronic module intended to be integrated into the frame formed by the frames 11 and 12).

An advantage that the opening 15 may not be exactly identical to the opening 14 (without the projections) is that it is possible to provide the same frame serving as a second partial frame for several shapes and dimensions (similar but not identical) first partial frame; in addition, the manufacturing tolerances of this second partial frame can be reduced.

In a variant not shown, the difference between the contours of the first and second partial frames can be located in the corners of the openings; thus, the contour of the opening 13 can in particular have a rectangular shape with very rounded corners, so as to leave material under the well defined corners of the opening 15. In addition, the difference between these contours of the first and second partial frames may not be as limited as in FIG. 1 and may in particular be constituted by zones extending over the whole of certain sides of the rectangular shape.

In addition, the general shape of the openings 13 and 15 is here rectangular but may, as a variant, depending on the format of the electronic module to be integrated, be a little more complex, for example polygonal (in particular with 5 to 10 sides, for example an octagon, i.e. a rectangle with cut corners), or be rounded (circular or elliptical), or any other shape.

These first and second partial frames are here represented as having a well-defined external contour, of rectangular shape, but this is not necessarily the case in practice because, to allow high production rates, it is possible to provide these frames in large plates, each plate having a plurality of openings; FIG. 2 thus represents the superposition of two plates 16 and 17 in which two pluralities of openings identical to the openings 13 and 14 of FIG. 1 are provided, no delimitation being yet materialized between the various frames (the outline of the frames of Figure 1 is delimited by dashed lines in this Figure 2, which is only a virtual delimitation).

Of course, a network of two-dimensional openings can be provided in each of the plates 16 and 17 in FIG. 2.

The partial frames of FIG. 1 make it possible to form a card, a section of which is presented in FIG. 3.

The order of the partial frames is reversed there in the sense that the first partial frame 11 is here above the second partial frame 12.

More precisely, this card is formed of a central layer denoted 21, sandwiched between two layers 22 and 23, and formed of the frame constituted by the partial frames 11 and 12 in the volume of which an electronic module 24 is integrated.

This module comprises a support 25, the external contour of which is close to that of the opening of the frame, in the sense that this internal contour can enter completely into the internal contour of the second partial frame 12, being larger than the internal contour of the first partial frame 11, so as to be able to come, through some of its peripheral zones, opposite the projections 14 of the first partial frame.

This electronic module 24 comprises, here on the same side of the support, various electronic components designated under the reference 26.

The face of the support 25 is at least approximately in the same plane as the face of the partial frame 12 which is opposite to the partial frame 11. As for the cumulative thickness of the partial frames 11 and 12 is less than the maximum thickness of the electronic module . The volume existing in the frame between the electronic module and the edges of the openings of these frames is filled with a filling material, in practice consisting of a resin 28.

The resin is advantageously a thermosetting resin; it can be a two-component resin, in particular in the case of a polyurethane resin; it can also be a resin polymerizing under a thermal or radiative effect (for example under the effect of UV rays).

The advantage of such a resin as a filling material is that, in practice, such a resin tends to wet the surfaces of the partial frames 11 and 12, to the point of creeping at the interface existing between them so as to contribute to their joining after solidification. This creep phenomenon at the interface between the partial frames occurs all the more easily as these partial frames are made of conventional materials in the field of smart cards, in particular PET or polycarbonate, even PVC, ABS. etc.

The module is fixed to the frame, in zones here designated by the reference 30. They may be localized zones for welding the material constituting the module and the material constituting the projections 14. As a variant, they may be points glue (or any other adhesive material). These fixing points make it possible to guarantee correct positioning of the module in the frame as soon as the resin is put in place.

It can be noted that, in the example shown, the support 25 of the electronic module 24 has substantially the same thickness as the second partial frame 12; this contributes to ensuring that the free face of the support is in line with the free surface of the second partial frame 12 when this support is in abutment against the projections 14 of the first partial frame 11.

Alternatively, the module has components on both sides of the support, in which case, to ensure that the module is entirely contained in the thickness of the body formed by the frame, the second partial frame must have a thickness equal to the sum of the thickness of the support and the maximum thickness of the components mounted on the face considered.

It is understood, however, that, for reasons of minimizing the overall thickness, it is advantageous to mount all the electronic components on the same side of the support (provided that this is possible).

The manufacture of such a body is shown diagrammatically in FIGS. 4 to 7.

This manufacturing involves having first and second partial frames 11 and 12, on the one hand (as in FIG. 1) and electronic modules 24, on the other hand, as shown in FIG. 4.

In a second step, it is possible, as described in particular in the documents WO - 2007/147727 and WO - 2007/147729 mentioned above, to assemble complete frames from the first and second partial frames of FIG. 1.

However, one can take advantage of the fact that these frames are in two parts in the following manner; it can be seen in FIG. 5 that the first partial frame 11 is positioned on a reference surface denoted 41 and that the module is positioned, head to tail, so as to come, at its periphery, bearing on the projections 14, the rest of the support being opposite the opening; the support 25 of the module is fixed to the first partial frame 11 at the location of these projections 14 (see references 30).

It is understood that the fixing of the support 25 to the first partial frame 11 can take place before the establishment of this partial frame against the reference surface (this can be easier), but that, depending on the fixing technique chosen, this fixing can also take place after this installation.

In order to facilitate the filling of the space situated between the reference surface 41 and the support 25 with its electronic components 26, it is advantageous to have already poured filling material 28 before positioning the first partial frame, or in in any case before positioning the module if it is not previously fixed to this first partial frame; however, as a variant, provision may be made to pour the filling resin after the elements 11 and 24 have been installed if there is sufficient space between the module and the first partial frame for this spill.

An advantage of putting filling material before putting the first partial frame in place on the reference surface is to guarantee good fixing of this frame to the reference surface when the latter is formed on a layer intended to be integral with the body 21 consisting of the future complete frame and the electronic module.

This is the case which is provided for in FIGS. 4 to 7 where the reference surface is formed by one face of an outer layer of a future microcircuit card which it is sought to manufacture.

In a subsequent phase, the second partial frame 12 is put in place, so that the support 25 is arranged in the opening of the latter (FIG. 6). This implementation is advantageously preceded by the deposition on the first partial frame of a thin layer of filling material for good connection between the two superimposed partial frames. As a variant, this deposition is carried out with an adhesive or another adhesive product distinct from the resin. But the implementation of a resin has the advantage of using only one product, for the joining and for the filling.

If one seeks to form only a middle layer of a future microcircuit card (it is then necessary to have chosen to avoid a joining of the first frame and of the filling material with the reference surface 41), the process s stop here.

If, on the other hand, it is sought to manufacture a complete microcircuit card, then a covering layer 23 whose thickness is chosen so as to make it possible to obtain a target thickness for the assembly obtained in FIG. 6 microcircuit card that we want to obtain.

This fixing can be obtained by means of a thin layer of resin deposited on the assembly of FIG. 6.

The assembly can then be subjected to a rolling treatment (shown diagrammatically by blanks of rollers 50 shown in dotted lines in FIG. 7) in order to bring the assembly to the desired thickness with as small a tolerance as possible.

The body of Figure 3 is thus obtained, to the nearest reversal.

The individualization of the cards, after possible steps of pre-personalization and / or personalization, is obtained by cutting the plates obtained by the process of FIGS. 4 to 7, in the desired format. Such plates may include several tens of future cards, or central layers of several tens of future cards (for example 24 in number).

This cutting can be done at the location of the dashed lines in FIG. 2, in which case each card comprises an electronic module and the frame formed by the partial frames 11 and 12.

As a variant, each contour of each card is at a non-zero distance from the contours of the adjacent cards, which makes it possible to give each card a contour which is not strictly complementary to the contour of the adjacent cards; the cards can then contain only part of the partial frames; we can even foresee that the frames are only used to position the electronic modules during the manufacturing process and that the cutting takes place inside the openings of the frames.

For example, the internal contour of the second partial frame 12 is similar to that of a card conforming to one of the formats defined by the ISO 7816 standard, however being a little bit smaller (for example by having dimensions which are smaller than those defined by the format considered from 1 to 3 mm).

If it is desired to form complete maps, the cover layers 22 and 23 can have a thickness of the order of 200 micrometers each, and the composition of the usual cover layers.

Otherwise, the surface 41 may consist of one face of a film intended to protect the layer 21 until it is integrated into a complete card; in such a case, the step in FIG. 7 can be limited to attaching to this layer 21 another protective film.

Such protective films can be made of Mylar® or PET in particular.

For example, the first partial frame has a thickness of between 50% and 75% of the frame formed by the two partial frames; thus, to obtain a central layer of 450 micrometers, one can choose a first frame of 300 micrometers thick and a second frame of 150 micrometers.

It is important to note that the invention allows a large choice of material for the production of the first frame. Indeed, certain materials have a limited thickness (eg less than 300 μm) and therefore cannot be used in the manufacturing techniques of the prior art. Thanks to the invention, it is possible to produce the first frame in a material chosen from those which can only have a small thickness and having a necking close to that of the support of the microcircuit. The material with the lowest shrinkage is PETF (0.5 - 1%); however, the use of a PETF monolayer can only be envisaged for fine substrates, since there is no PETF layer greater than 300 μm at affordable costs.

* * *

Claims (12)

1. A method of manufacturing at least one central layer (21) of a microcircuit card, this central layer comprising an electronic module (24) formed by a printed circuit support (25) provided on at least one of its faces d '' at least one electronic component (26) according to which: * on the one hand, this electronic module (24) is formed with an external contour determined by the external contour of the printed circuit and, on the other hand, a frame of constant thickness having, inside a future external contour of the card, an opening (13, 15) delimited by an internal contour capable of surrounding the external contour of the printed circuit except in a few zones (14) of this internal contour which protrude towards the interior of the opening , these few zones having a reduced thickness compared to the constant thickness of this frame outside these zones, * these zones of reduced thickness compared to that of the frame are fixed to zones facing the periphery of the support to printed circuit (24), and * the space remaining between this electronic module (24) and this frame (11,12) is filled with a resin so as to define a body (21) having the thickness of this frame, characterized in that we form the frame in two pieces separated adapted to be superimposed, namely a first partial frame (11) having a first opening (13) delimited by said internal outline of the frame and a thickness (e1) equal to said reduced thickness, and a second partial frame (12) having a second opening (15) delimited by a second internal contour surrounding the opening (13) of the first partial frame as well as said projecting zones (14), these two separate parts then being joined, the cumulative thickness of the first and second frames partial thus joined defining the constant thickness of said frame 2. Method according to claim 1, according to which the second internal contour of the second partial frame (12) runs along the first internal contour of the first partial frame (11) while bypassing the zones (14) that this first internal contour of the first partial frame projecting from the external contour of the module. 3. Method according to claim 1 or claim 2, according to which the thickness of the first partial frame is chosen between 50% and 75% of that of the frame. 4. Method according to any one of claims 1 to 3, according to which the outer outline of the card is delimited in said body so that it surrounds the inner outline of the frame. 5. Method according to any one of claims 1 to 4, according to which the electronic module (24) is fixed to the areas of reduced thickness before securing the first and second partial frames (11,12). 6. Method according to any one of claims 1 to 5, according to which the resin is deposited on a reference surface (41) before positioning the first partial frame (11) on this same reference surface. 7. Method according to any one of claims 1 to 6, according to which, to secure the partial frames, a layer of filling resin is deposited on the first partial frame (11) before positioning the second partial frame (12 ). 8. Method according to any one of claims 1 to 7, according to which the projecting zones (14) have a triangle shape pointing towards the inside of the opening of the frame. 9. Method according to any one of claims 1 to 8 according to which the projecting zones (14) are in a number between 2 and 5, limits included. 10. Method according to any one of claims 1 to 9, according to which the first and second partial frames are part of plates each having the same number of openings, the body obtained after the step of filling with resin then being cut, according to said external card contours, into several individual cards. 11. Method according to any one of claims 1 to 10, wherein the resin is thermosetting. 12. Central layer of microcircuit card comprising a microcircuit module (24) formed by a printed circuit support (25) provided on at least one of its faces with electronic components (26) and a frame surrounding this module having a thickness at least equal to that of this electronic module by having an opening (13, 15) delimited by an internal contour capable of surrounding the external contour of the printed circuit support except in a few zones (14) of this internal contour which come in protruding towards the inside of the opening, these few zones (14) having a reduced thickness compared to the constant thickness of this frame outside these zones, the printed circuit support being fixed to these portions of reduced thickness and the space between this electronic module and this frame being filled with a resin, characterized in that this frame is formed by a first partial frame (11) having a first opening (13) delimited by led it internal contour of the frame and a thickness (e1) equal to said reduced thickness, and a second partial frame (12) having a second opening (15) delimited by a second internal contour surrounding the opening (13) of the first partial frame thus that said projecting zones (14), the cumulative thickness of the first and second partial frames assembled together being equal to the constant thickness of said frame. 1/2 41 /: 1 ______ 13 .22 28 26 14 A _ X __ /. __; / / 26 ___ \ 7 ' 21- ^ dHH · " Λ. j: _τ ... .... ...... 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