WO2015040027A1

WO2015040027A1 - Method and device for manufacturing a chip card, and chip card obtained by said method

Info

Publication number: WO2015040027A1
Application number: PCT/EP2014/069722
Authority: WO
Inventors: Jeremy Renouard; Georges Cogno; Alexis Froger; Thierry Jager
Original assignee: Gemalto S.A.
Priority date: 2013-09-18
Filing date: 2014-09-16
Publication date: 2015-03-26
Also published as: EP2851848A1

Abstract

The smart card according to the invention is manufactured by injection moulding plastic material in a mould comprising a shearing assembly comprising a punch (41) and a die (42) that slide in the opposite walls (31, 32) respectively of the mould, in a sliding direction that is orthogonal to the overall plan. The card is at least partially sheared in the attaching zones (40) between a card body in a first format (3) and a card body (4) in a second smaller format, by simultaneously displacing the die and the punch, between which the card body (4) is held, in one direction and then in the opposite direction to bring the card body (4) in the second format back to its initial position in relation to the card body (3). Application particularly for the manufacturing of multi-format smart cards.

Description

METHOD AND DEVICE FOR MANUFACTURING A CHIP CARD, AND CHIP CARD

OBTAINED BY SAID METHOD

This invention relates to a new method for manufacturing smart cards, in particular those designed for use in mobile telephones. It also relates to a new device for implementing the method, and a smart card made using the method. The smart cards concerned by the invention are particularly subscriber identification modules, known as SIM cards. SIM cards are designed to be incorporated into mobile telephones. SIM cards exist in several standardised formats defined by the form factors UICC (Universal Integrated Circuit Card) 2FF, 3FF or 4FF. Miniaturisation and increases in the functions of mobile telephones have led to the formats of SIM cards becoming smaller and smaller. Thus, the form factor 2FF (25 x 15 mm) gave way to 3FF (15 x 12 mm) and then to 4FF, which is even smaller.

Typically, a SIM card comprises (a) a card body, commonly made by injection moulding, and (b) an integrated circuit chip fixed to that card body. The card body substantially takes the shape of a fine rectangular parallelepiped. Generally, for manufacturing and marketing 2FF, 3FF and 4FF card formats, the smaller card body is encompassed within a perimeter that corresponds to a larger format, generally the format that is immediately greater. Thus, typically, a SIM card may be manufactured and marketed in IFF format, corresponding to the credit card format, with a body encompassing a min-SIM card in 2FF format, which can encompass a micro-SIM card in 3FF format etc., like the card represented in figure 1, which is then called a multi- format card. The microchip is of course fixed to the smallest card, in a slot that is hollowed out in the thickness of the card.

To use the SIM card, depending on the format required by the device into which the card is to be inserted, the user detaches the card in the required format from the larger card body. In order to make the detachment process as easy as possible, the perimeter of each format is marked by a dotted line which weakens the material of the card body in order to facilitate the separation between the required card format and the larger card body, while holding the said card bodies together adequately till they are deliberately detached by the user. A first way of forming dotted lines is to form a groove that goes through the whole thickness of the larger card body and demarcates the perimeter of the smaller card. That groove is a through groove but is discontinuous, so as to leave attaching tabs, typically three, to hold the smaller card body on the larger card body, and additionally, the thickness of the tabs is reduced, and they all contain a break line aimed at facilitating the subsequent detachment of the smaller card, typically a mini-SIM card, so that it can be detached from the remainder of the card body and incorporated into mobile telephones that accept the mini-SIM card format. A conventional method for making these dotted lines is the moulding method, where the card is injection moulded and the recess designed for accommodating the microchip, the dotted lines with the attaching tabs and the break lines of the tabs are made during the moulding process, by using moulds with mobile cores, moved towards the inside of the mould just after the plastic material is injected in the mould, when the plastic material is not yet solidified. The use of such cores makes it possible to directly make thinner material zones such as said tabs and their break lines while moulding. This manufacturing method makes it possible to manufacture cards for a lower cost, as it makes it possible to mould the perimeter of the SIM card, the recess for the microchip, the attaching tabs and the break lines in a single operation.

The method is commonly used to make dotted lines, for example between the IFF and 2FF formats, but is not suitable for small formats and even less so for multi- format cards, typically between 3FF and 4FF, because the small distances between the different dotted lines make it impossible to form dotted lines through the total thickness of the card, which require a certain minimum width between such lines. Other methods are used for making such dotted lines.

Cards are also known in which the dotted lines and the recess for the microchip are made by machining or applying another method for the removal of material, using appropriate tools such as laser beams, high-pressure jet etc. The making of dotted lines by punching is also known. According to that last technique, tools with cutting blades shaped to correspond to the shape of the perimeter of the required card are used, and the blades are made to penetrate into the material of the card, which is first prepared by moulding in the form of a plate of plastic material with the final thickness of the card, while leaving, at least in certain zones of the dotted line, material that is thick enough to hold the card in the larger card body and weak enough to allow the material to break in said zones when the card is deliberately detached. This method makes it possible to obtain a dotted line and break lines that are finer than with the moulding method. Further, thanks to the fineness of the dotted lines, a SIM card can be put back into its slot after it has been detached by breaking the break lines, as the mere fitting of the card in its slot offers sufficient holding. This method is used to make dotted lines in the 3FF and 4Ff formats on multi-format cards combining the 2FF/3FF/4FF formats, for example.

However, the method is costly, approximately three times as much as the moulding method, because it particularly makes it necessary to rework the card after the first moulding operation and to use precise tools that provide the exact material thicknesses remaining after punching, which are approximately 100 micrometres.

Further, whether in that last case or in the case of manufacturing by moulding, the breaking of material at the break lines or dotted lines may leave ragged edges in the material or burrs that are harmful for the subsequent insertion of the card in the device into which it is to be inserted. The need to leave physical attachments, in the form of zones with residual material or membranes to join the SIM card to the larger card body results in the need for force to break the physical attachments, with a risk of damage to the microchip placed in the card.

The discontinuity of the surface of a larger card, constituted by the presence of the break lines of a card body of a smaller format, particularly when a through groove determines the perimeter of that smaller card, can create problems while inserting the larger card in a device, when the contacts of that device catch or lock in the hollows formed by said grooves or break lines.

This invention is aimed at remedying the problems identified above, and particularly at proposing cards, particularly multi-format cards, for a lower cost. In particular, it is aimed at precisely creating dotted lines for making such lines that are very close to each other, as is the case for example between the 3FF and 4FF formats. It is also aimed at avoiding any burrs that may remain at the perimeter of a card after it is detached from a larger card body. It is also aimed at simplifying the manufacturing of such cards, particular by making it possible to mould the card and create the break lines in a single operation, which would thus be faster and more economical. Lastly, it is aimed at allowing the making of multi-format cards by moulding with no additional punching operation. With those objectives in mind, the invention relates to a method for manufacturing a smart card comprising a card body in a first format encompassing a card body in a second format smaller than the first one, co-planar with the card body in the first format, wherein the perimeter of the card body in the second format is defined by a predetermined shape line and the card body in the second format is attached to the card body in the first format in a plurality of attaching zones located on said line; the card is manufactured by injection moulding of plastic material according to the method.

According to the invention, the method is characterised in that after the mould is filled and before the plastic material solidifies, the card is subjected to at least partial shearing in said attaching zones by displacing the whole card body in the second format in relation to the card body in the first format in a direction orthogonal to the overall plane of the card, followed by displacement in the reverse direction to bring the card body in the second format to its initial position, particularly in the same plane as the card body in the first format.

The invention thus makes it possible to make smart cards in different formats, particularly multi-format cards, using a moulding method with no additional punching steps.

The time of said shearing depends particularly on the type of plastic material, its fluidity and thus the temperature of the part.

Typically, shearing is carried out after the temperature of the injected plastic material drops below the vitreous transition temperature of said plastic material. Thus, the plastic molecules at the shearing line are broken, but no spurs or other surface discontinuities are created at the line. At the shearing line, shearing is carried out at a temperature that is still high and capable of forming an interface between the edges of the card in the second format and the card in the first format, which extends orthogonally with the overall plane of the card. The result at that interface, particularly because of the differences in shrinkage of the material as it cools, is a sort of tight fit that can hold the card in the second format in the card in the first format that surrounds it due to the friction resulting from such a tight fit, while allowing the subsequent detachment of the card in the second format with card extraction force that is sufficient to overcome said friction. That force can be controlled by the choice of the time when the shearing is carried out, by the amplitude of the displacement leading to shearing, by the displacement speed and the pressure applied, and by the allowance between the punch and the die used for shearing. That force can thus be low enough to avoid any risk of the microchip being destroyed.

The amplitude of the displacement of the card in the second format in relation to the card in the first format is preferably located between 25 and 100% of the thickness of the card; that amplitude also depends on the nature and properties of the plastic material and other moulding parameters, particularly the temperature during injection and the cooling conditions. Said attaching zones may be discontinuous along the line defining the perimeter of the card in the second format, in which case through grooves are formed along that line between said attaching zones.

In a preferred arrangement, said attaching zones extend continuously over the entire perimeter of the card. The smaller card is then held in the larger card over its entire perimeter, and there is no discontinuity of surface at the separating line, over the entire length of the line.

The invention also relates to an injection mould for manufacturing a smart card using the aforementioned method, where the mould comprises a slot extending in the overall plane with dimensions corresponding to the dimensions of the largest card to make. According to the invention, the mould comprises at least one shearing assembly comprising a punch and a die that slide respectively in the opposite walls of the mould, in a sliding direction orthogonal with the overall plane, wherein a flat front of the punch and a flat front of the die extend in parallel with dimensions identical to the dimensions of the smaller card, and the mould comprises means to control the displacement of the die and punch arranged to simultaneously displace the die and punch along said sliding direction while keeping a constant distance between said flat fronts, equal to the thickness of the smaller card and so generally equal to the distance between the opposite walls of the mould.

In one alternative embodiment, for making multi-format cards, the mould comprises several associated punch and die assemblies that can slide respectively inside each other. Thus, a first assembly comprising a punch and a die sliding directly in the walls of the mould may be dedicated to shearing along the line corresponding to the perimeter of a 2FF card and a second assembly comprising a punch and a die sliding in the punch and the die respectively of the first assembly, dedicated to shear along the line corresponding to the perimeter of a card in 3FF format.

The invention also relates to a smart card obtained using the aforementioned method, comprising a card body in a first format encompassing a card body in a second format smaller than the first one, co-planar with the card body in the first format, wherein the perimeter of the card body in the second format is defined by a predetermined shape line and the card body in the second format is attached to the card body in the first format in a plurality of attaching zones located on said line. The card according to the invention is characterised in that it has an interface between the edges of the card in the second format and the card in the first format that extends orthogonally to the overall plane of the card, wherein said edges are smooth, without any breaking roughness or jagged edges that necessarily remain after the detachment of cards made using earlier methods, where there is necessarily a tear break in the attaching zones during detachment.

It must also be noted that the card according to the invention has a surface that is visually continuous, with no relief at the dotted line.

As with punched cards, a SIM card according to the invention may be put back in its slot in the card body in the larger format after it has been extracted from it. One advantage of the invention is that in such a case, the card remains held in place as it is held before it is extracted, by being in edge-to-edge contact with its slot in the larger card, over the entire thickness of the card. Comparatively, in the case of punched cards, the contact obtained after the card is reinserted is only made on the small thickness of the dotted zones remaining between the punches during punching, and thus with a holding capacity that is far weaker than with this invention.

Other characteristics and benefits will appear in the description below of a card according to the invention, and the method and the device for manufacturing the card.

Reference will be made to the attached drawings, where:

- figure 1 is a view of a multi-format card according to the invention,

- figures 2 to 4 are schematic illustrations of the manufacturing mould and the successive stages of the method according to the invention,

- figure 5 is a detailed cross- sectional view of the attaching zone of a card made by punching - figure 6 is a similar comparative view, in the case of this invention

- figure 7 is a sectional view of the principle of the tooling used to make a multi-format card. The card represented in figure 1 is a multi-format smart card comprising a first larger card body 1 in the IFF credit card format, demarcated by its perimeter cl and incorporating a SIM card with a card body 2 in the 2FF or mini-SIM format, demarcated by a dotted line c2. In its turn, that card body in 2FF format incorporates a card body in 3FF or micro-SIM format, demarcated by a dotted line c3, which in turn incorporates a card body in 4FF or nano-SIM format, demarcated by a dotted line c4, which carries the electronic module 9 placed in a recessed slot 21 formed in the last card body.

The perimeters of the different card bodies are represented by a fine line for demarcating them, but it must be understood that there is in fact virtually no card surface discontinuity between the surfaces of the different card bodies, as can be seen in the details of figure 6.

That figure 6 represents an enlargement of the cross-section of the attaching zone between the card body 4 comprising the slot 49 for the electronic module and the larger card body 3. It can be seen that the surfaces 12 and 13 of the opposite sides of the card body 4 are exactly co-planar with the surfaces 14 and 15 respectively of the card body 3. Further, the facing edges 16 and 17 of the two card bodies are orthogonal to the surfaces 14, 15, 16 and 17 and uniform and free of roughness, extending parallel to one another. The two edges, 16 and 17, are therefore in contact over the entire thickness 'e' of the card. A small allowance is symbolically represented between the two edges, but it must be understood that as explained above, there is in fact at that interface a tight fit resulting from the manufacturing method according to the invention, the value of which is controlled with the difference in material shrinkage of the two card bodies 3 and 4 and the fit between the punch and the die.

For comparison, figure 5 represents the corresponding interface between the card bodies 3' and 4' of a card where the dotted lines have been made by punching. It can be seen easily that in that case, there are at the interface two zones 27 and 28 with a sloping side, resulting from the necessarily bevelled shape of the blades of the punching tools and an attachment 25 in plastic material that remains between those two zones to attach the two card bodies 3' and 4' to each other before the card in 4FF format with the card body 4' is detached from the card body 3' by breaking the attachment 25 in order to be used in a device.

That comparison clearly brings out the differences between a card according to the invention visible in figure 6 and a card obtained by punching using the prior art, visible in figure 5. Further, the surface discontinuities resulting from the presence of sloping slides in the case of the card according to the prior art can be seen, and are absent in the card according to the invention. Even further, it can be easily understood that after the card bodies are detached, the edge of the card body 4 will be perfectly smooth, while the edge of the card body 4' will have a burr or traces of tearing of the material resulting from the break of the attachment 25.

In figures 2 to 4, the mould according to the invention is represented schematically, with only the part concerned by the invention, it being understood that the other parts of the mould are identical to injection moulds according to the known art. The mould comprises two walls 31, 32 that between them determine a chamber with dimensions corresponding to the card body in the larger format, commonly the IFF format. In the description in this example, it will be considered for the purposes of simplification that a SIM card body 4 is being made in a larger card body 3, it being understood that could apply to the formation of a body in 4FF format in a 3FF body or a 3FF format in a 2FF format or a 4FF format in a 2FF format etc. The mould comprises a shearing assembly comprising two elements that will be called the punch 41 and the die 42, it being understood that as part of this invention, there is no relative displacement of said punch 41 in relation to said die 42 during the step when the method is implemented, but, as will be seen below, only the simultaneous displacement of the punch and the die in relation to the fixed walls 31 and 32 of the mould. The slot 49 of the electronic module may be made by using an independent core, in a manner known in itself; in the case of this invention, such a core would slide in the punch 41. However, in a specific step prior to that of the implementation of the method according to the invention, the punch 41 may be used as the mobile core to form the slot 49 for the electronic module. In that case, the punch and the die come together during that preliminary stage carried out when the mould is filled; after that, in the shearing step according to the invention, the punch and the die move together. In the example of figures 2 to 4, the punch 41 is mounted to slide in the wall of the mould 31 and the die 42 slides in the wall of the mould 32. The side 421 of the die is flat, with a shape corresponding to the shape of the card body 4. The front end 412 of the punch comprises a flat surface 411 with an external shape also corresponding to the shape of the card body 4 and a boss 413 acting as a mobile core for making the slot 49 as explained above. The penetration of the punch to form the slot 49 may be carried out after injecting the plastic material in the mould.

Figure 2 represents the punch 41 and the die 42 in the position taken up after that prior step of die penetration. In that position, the side 421 of the die is substantially flush with the surface of the lower wall 32 of the mould and the surface 411 of the punch is just flush with the surface of the upper wall 31.

In accordance with the invention, from that position and just after the temperature of the plastic material drops below the vitreous transition temperature of said plastic material, the die 42 and the punch 41 are simultaneously made to slide in relation to the walls of the mould, as illustrated in figure 3, then they are immediately brought back to their initial position as illustrated in figure 4. During those two movements, the distance between the punch and the die remains constant.

That to-and-fro movement carried out while the temperature of the plastic material contained in the mould drops below the vitreous temperature transition leads to a break, which is at least partial, in the fibres of the plastic material at the perimeter 40 of the card body 4, acting as a shear but without completely detaching the card body 4 from the card body 3 and by bringing back, at the end of the movement, the card body 4 to its initial position in relation to the card body 3.

In this example, the displacement travel of the die and the punch is approximately a quarter of the thickness of the card, but it may be typically located between 25 and 100% of the thickness of the card body.

As an example, for manufacturing a card in ABS (acrylonitrile butadiene styrene), shearing is carried when the temperature of the plastic material is approximately 80 to 150°C and the common travel of the punch and the die is approximately half the thickness of the card, or approximately 400 micrometres. Figure 7 illustrates the implementation of the method according to the invention in the case of the making of a card with two formats. In this case, the mould comprises two coaxial shearing assemblies that slide one in the other, namely a first assembly similar to that described in the previous example, capable of forming the dotted line of a smaller card, for example 4FF, and the slot of the microchip, and the first assembly is mounted to slide in a second assembly comprising a tubular die 52 and a tubular punch 51, with external dimensions corresponding to the dimensions of the larger card body, for example 3FF, which slide in the walls 31, 32 of the mould. By displacing each of the assemblies successively, or simultaneously but in opposite directions, the shearing operation according to the invention is carried out both for cutting the 4FF format and the 3FF format.

Of course, the description above can be applied to other formats or other card format combinations.

Even though it is indicated in the previous examples that the surfaces of the punches and dies are co-planar with the surfaces of the walls of the mould, which is the case when the different card bodies have the same thickness, a card according to the invention could of course be made where the thicknesses of the different formats are different, in which case the surfaces in question would not be co-planar, but the principle of the invention would remain the same as can be easily understood by a person of the art.

Claims

1. A method for manufacturing a smart card comprising a card body (3) in a first format encompassing a card body (4) in a second format smaller than the first one, wherein the perimeter (c4, c3 etc.) of the card body in the second format is defined by a predetermined shape line and the card body in the second format is attached to the card body in the first format in a plurality of attaching zones located on said line; the card is manufactured by injection moulding of plastic material according to the method,

characterised in that after the mould is filled and before the plastic material solidifies, the card is subjected to at least partial shearing in said attaching zones (40) by displacing the whole card body (3) in the second format in relation to the card body (4) in the first format in a direction orthogonal to the overall plane of the card, followed by displacement in the reverse direction to bring the card body in the second format back to its initial position.

2. A method according to claim 1, characterised in that shearing is carried out after the temperature of the injected plastic material drops below the vitreous transition temperature of said plastic material.

3. A method according to any of the foregoing claims, characterised in that the amplitude of the displacement of the card in the second format in relation to the card in the first format is located between 25 and 100% of the thickness of the card

4. A method according to any of the foregoing claims, characterised in that said attaching zones extend continuously over the entire perimeter of the card in the second format.

5. An injection mould for making a smart card, comprising a slot extending in an overall plan and with dimensions corresponding to the dimensions of the larger card to be made, characterised in that the mould comprises at least one shearing assembly comprising a punch (41) and a die (42) that slide respectively in the opposite walls (31, 32) of the mould, in a sliding direction orthogonal with the overall plane, wherein a flat front (411) of the punch and a flat front (421) of the die extend in parallel with dimensions identical to the dimensions of a smaller card, and the mould comprises means to control the displacement of the die and punch arranged to simultaneously displace the die and punch along said sliding direction while keeping a constant distance between said flat fronts, equal to the thickness of the smaller card.

6. An injection mould according to claim 5, characterised in that it comprises several assemblies (41, 42; 51, 52) of associated dies and punches that slide respectively inside each other.

7. A smart card comprising a card body (4) in a first format encompassing a card body (3) in a second format that is smaller than the first, wherein the perimeter (c3, c4) of the card body in the second format is defined by a predetermined shape line and the card body in the second format is attached to the card body in the first format in a plurality of attaching zones located on said line, characterised in that it has an interface between the edges (16, 17) of the card in the second format and the card in the first format in said attaching zones, which extends orthogonally in relation to the overall plane of the card, wherein said edges are smooth, free of breaking roughness or jagged edges.

8. A smart card according to claim 7, characterised in that it has a continuous surface with no relief at the dotted lines.

9. A smart card according to claim 7, characterised in that it is made of plastic material, particularly ABS.