Abstract:
A standard size smart card has a flat support with a slot in the support to define the boundary of a minicard attached to the support by lugs. Each lug has two types of grooves opposite each other so they provide sufficient resistance to bending and flexing. One of the grooves is configured so it starts to crack when the minicard is purposely subject to pressure.

Description:
This disclosure is based upon, and claims priority from, French Patent Application No. 98/01370, filed Jan. 22, 1998, and International Application No. PCT/FR99/00052, the contents of which are incorporated herein by reference. 
     BACKGROUND OF THE INVENTION 
     The present invention relates to a standardized integrated circuit contact card, also usually referred to as a smart card. 
     The invention more particularly relates to a standardized smart card which can be transformed irreversibly into a standardized mini smart card. 
     The invention thus relates to a standardized integrated-circuit contact card of the type having a support in the form of a rectangular plate delimited by two long longitudinal edges and two short transverse edges, front and rear, which carries at least one electronic microcircuit and whose reverse face has a series of contact areas, arranged close to the front transverse edge of the card, for the electrical connection of the microcircuit to an operating circuit belonging to a device having for example a connector in which the card is fitted so that its contact areas cooperate with contact blades on the connector, and of the type having a slot with a substantially rectangular contour formed in the support, around a portion including the microcircuit and the series of contact areas, in order to delimit a detachable standardized minicard which is connected to the card support by several lugs, produced in one piece with the support, which extend between the internal edges of the cutout formed by the slot in the card and the facing edges of the minicard which are roughly parallel to the edges of the card. 
     According to such a known design, which is for example illustrated in the document EP-Bl-0.521.778, it is possible to simply transform the card, or a large card known as an SIM card, whose format is in accordance with the international standards GSM 11.11 and ISO 7816, into a standardized mini SIM card, whose dimensions are also defined by the international standard GSM 11.11, by detaching the latter from the card by breaking the lugs or connecting bridges, this rupture being able to be effected notably manually by pressing the minicard overall in a vertical direction perpendicular to the overall plane of the card. 
     This known design makes it possible to supply the card “complete” to a user, that is to say of course without detaching the minicard, to enable him to use the chip with a card in one or other of the two formats (card or minicard) according to the receiving apparatus in which he has to insert the card. 
     The product manufactured and supplied to the users must, in addition to the standards mentioned above defining the design and geometry of the two types of card, comply with other parameters and requirements. 
     Each of the two cards must in particular be able to meet, in accordance with the ISO standard, mechanical strength tests including notably repeated bending/torsion cycles, without there being any visual or functional degradation of the chip, the module incorporating the chip and inserted in the card support, or the plastic body of the card forming the support proper. 
     These mechanical constraints must in particular be withstood by the large card, as well as of course by the minicard. 
     For practical reasons, it is desirable for the minicard to be able to be detached easily from the body of the large card by a manual operation, without using any specific tool and without impairing the functioning and subsequent reliability of the minicard thus obtained. 
     It is desirable to improve the structure of the card in order in particular to facilitate still further the manual separation, whilst guaranteeing resistance to bending/torsion in accordance with the ISO standard. 
     Provision is for example made for the use of more fragile chips or modules in the future and, in this case, it is preferable not to have any risks, even insignificant, of damaging the chip or module. 
     In addition, one or the other of the two cards must be able to be used without presenting problems of insertion or extraction of the card into or from its receiving device, and particularly in the connector, more particularly when a card is introduced into the connector in a direction substantially parallel to its overall plane with its transverse insertion edge corresponding, in the case of the large card, to its front transverse edge adjacent to the contact areas for connection of the chip and, in the case of the minicard, to one or other of its two parallel opposite transverse edges. 
     It is also desirable, in particular when the large-format card is used, for the cutout slot, and/or complementary grooves constituting incipient breaks in the connecting lugs, not to damage the elastic contact blades of the connector because of its repeated passage opposite the free contact ends of the contact blades of the connector during repeated operations of inserting and extracting the card. 
     SUMMARY OF THE INVENTION 
     In order to remedy the drawbacks which have just been mentioned and to satisfy the different requirements for reliability of the cards and connectors, the invention proposes a card of the type mentioned above, characterized in that each lug has two types of groove opposite each other, shaped so as to be sufficiently resistant to bending/torsion forces in accordance with a standard, one of the grooves however also being shaped so as to more easily initiate a crack by intentional manual pressure on the minicard. 
     According to other characteristics of the invention: 
     the card has three connecting lugs including a first lug extending longitudinally from the front transverse edge of the minicard adjacent to the front transverse edge of the card, whose width is at least equal to the width of the series of contact areas arranged close to the front transverse edge of the minicard, and opposing second and third lugs which each extend transversely from a longitudinal edge of the minicard, 
     the second and third lugs are aligned transversely and are situated close to the series of contact areas; 
     the second and third aligned lugs are situated approximately 17 mm from the transverse edge of the minicard from which the first lug extends; 
     the width of the first lug is approximately 11 mm; 
     the width of the second and third lugs is approximately 1.2 mm; 
     each of the lugs has, at least on its front face or reverse face, a groove parallel to the edge of the minicard from which the lug extends so as to constitute a portion with a reduced thickness constituting an incipient break in the lug; 
     the first lug has, at least on its front face or reverse face, a groove which, in cross-section, has a V-shaped profile, one leg of which, adjacent to the edge of the minicard, extends perpendicularly to the overall plane of the card; 
     the first lug has two identical aligned opposing grooves formed in the front face and reverse face; 
     each of the second and third lugs has, at least on its front face or reverse face, a groove which, in cross-section, has a V-shaped profile, one leg of which, adjacent to the edge of the minicard, extends perpendicularly to the overall plane of the card; 
     each of the second and third lugs has, at least on its front face or reverse face, a groove which, in cross-section, has a profile substantially in the shape of a trapezium, one edge of which, adjacent to the edge of the minicard, extends perpendicularly to the overall plane of the card and whose small base, belonging to the bottom of the groove, lies with an inclination with respect to the overall plane of the card; 
     each of the second and third lugs has two opposing aligned grooves, on its front face a V-shaped groove and on its reverse face a groove substantially in the shape of a trapezium. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Other characteristics and advantages of the invention will emerge from a reading of the following detailed description, for an understanding of which reference will be made to the accompanying drawings, in which: 
     FIG. 1 is a plan view of a card according to the teachings of the invention; 
     FIG. 2 is a view similar to that of FIG. 1 on which the part of the card including the minicard has been depicted to a larger scale; 
     FIGS. 3 and 4 are views in section along the lines  3 — 3  and  4 — 4  in FIG. 2; 
     FIG. 5 is a view to a larger scale of the detail D 5  in FIG. 3; 
     FIG. 6 is a partial view in cross-section along the line  6 — 6  in FIG. 5; 
     FIG. 7 is a view to a larger scale of the detail D 7  in FIG. 4; 
     FIG. 8 is a partial view in cross-section along the line  8 — 8  in FIG. 7; 
     FIG. 9 is a plan view of another card according to the teachings of the invention; 
     FIG. 10 is a partial view in cross-section along the line  10 — 10  in FIG. 9; 
     FIG. 11 is a plan view of another card according to the teachings of the invention; and 
    
    
     DETAILED DESCRIPTION 
     FIG. 12 is a partial view in cross-section along the line  12 — 12  in FIG.  11 . 
     FIG. 1 depicts a standardized card C, of a known general design, which is a smart card consisting essentially of a body  10  in the form of a rectangular sheet with rounded corners, which is generally made from plastics material and which incorporates an electronic microcircuit (not shown) associated with the support  10  in accordance with any one of the known techniques, for example in the form of a module plugged into the support  10 . 
     The face  12  of the card C visible in FIG. 1 is the front face of the card, which has a zone  14  in which six or eight areas  16 , or pins, are arranged for the electrical connection of the electronic microcircuit to an operating circuit by means of an electrical connector (not shown) belonging for example to a read-write device. 
     The areas  16  are disposed in a standardized design and extend roughly parallel to each other and aligned in pairs in the general longitudinal direction of the card, that is to say in the direction parallel to the two parallel opposing longitudinal edges  18  and  20  of the support  10 . 
     In accordance with the standard, the zone  14  including the series of areas  16  is arranged close to a transverse edge  22  of the support  10 , which is referred to here as the front transverse edge with reference to the normal direction of insertion of the card C, from rear to front, into a connector. 
     The support  10  is also delimited by an opposite rear transverse edge  24  parallel to the front transverse edge  22  and perpendicular to the two longitudinal edges  18  and  20 . 
     The other face  13  forming the reverse face of the card (see FIG. 3) is parallel to the front face  12 , these two faces determining the standardized thickness of the card C, which is between 0.68 and 0.84 mm and preferably between 0.80 and 0.84 mm. 
     According to a known design, the support  10  has a slot F with a substantially rectangular contour and which extends roughly around a portion of the body  10  of the card C which includes the electronic microcircuit and the zone  14  including the series of electrical connection areas  16 . 
     The slot F thus delimits on the inside a standardized minicard MC with a substantially rectangular contour, which is delimited by two parallel and opposite longitudinal edges  26  and  28  which are respectively parallel and adjacent to the longitudinal edges  18  and  20  of the card C. 
     The minicard MC is also delimited by a first transverse edge  30 , here referred to as the front transverse edge, which is parallel and adjacent to the front transverse edge  22  of the card C. 
     Finally, the minicard MC is also delimited by another rear transverse edge  32  opposite and parallel to the front transverse edge  30 , which is an edge having a chamfer  34  formed in the front face  12  of the support  10  and which is connected to the longitudinal edge  28  by a cant  36 , with standardized shape and dimensions, in order to constitute a means of determining the direction of insertion or fitting of the minicard MC in a connector. 
     The function of the chamfer is to prevent any catching of the minicard against the components of a mobile telephone, when it is being removed from it. This is because some mobiles have elastic means which have a tendency to press the minicard against the connector and to lift the end  32  of the minicard out of the overall plane of the card. The chamfer can be produced by compressing the material of the card by means of an appropriate tool. 
     The slot F can be produced according to a known technique, using for example a cutting tool/punch and a complementary die, or by producing it by cutting by means of a pressurized water jet or a laser beam. 
     The cutting of the slot F is incomplete, that is to say, according to a known general design, lugs or bridges are left which connect the minicard MC to the body  10  of the card C in order to constitute a “bi-standard” assembly enabling the end user to use the large-format card C or the minicard MC, according to the application, such an option being in particular necessary when the card contains data relating to a subscription to a telephone communication network to which connection is made by portable handsets which, according to the manufacturer, use the two types of card. 
     The connecting lugs are produced in one piece, that is to say they are formed from portions of the support  10  which are not cut when the slot F is produced. 
     In accordance with the teachings of the invention, the connecting lugs are three in number and are distributed in an arrangement which will now be described in more detail, notably with reference to FIG.  2 . 
     The first lug B 1  extends longitudinally, towards the left looking at FIG. 2, from the front transverse edge  30  of the minicard MC which is adjacent to the zone  14 , in the direction of the front transverse edge  22  of the card C. 
     In accordance with the teachings of the invention, the first lug B 1  is a lug of great width L 1 , for example approximately 11 mm, which is greater than the width L 2  representing the width and passage of the contact blades of a connector with respect to the zone  14  carrying the electrical connection areas  16 . In addition, the lug B 1  extends at least opposite this zone so that there is no portion of slot F between the front transverse edge  22  of the card C and the zone  14  in order to prevent damaging the contacts of a connector by the passage of a portion of slot F over the free ends of the contact of the connector. 
     In addition, the first lug B 1  of great width L 1  confers mechanical properties on the card C and on the minicard MC enabling them to resist, in association with the other lugs, the torsion and bending forces mentioned previously. 
     The other two lugs for connecting the minicard MC to the card C are, in the embodiment illustrated in the figures, two identical and opposite lugs B 2  and B 3 . 
     The first lug B 2  extends transversely from the longitudinal edge  26  of the minicard MC in the direction of the longitudinal edge  18  of the card C. 
     In the same way, the third lug B 3  extends transversely from the longitudinal edge of the minicard MC in the direction of the longitudinal edge  20  of the card C. 
     The second and third lugs B 2  and B 3  are aligned in the same transverse direction and are situated close to the zone  14 , that is to say their mean transverse axis, corresponding to the section line  4 — 4  of FIG. 2, is situated at a distance from the front transverse edge  30  of the minicard MC of approximately 17 mm. 
     In accordance with the teachings of the invention, there is no other connecting lug, and there is in particular no connecting lug extending from the rear transverse edge  32  of the minicard MC to connect it to the support  10  of the card C, which is particularly advantageous in so far as this edge often constitutes the edge for insertion of the minicard into a connector, which thus has no burr which might impair correct positioning of the minicard with respect to the connector and might damage the contact blades on the latter. 
     As can be seen in particular in FIG. 2, the second and third lugs B 2  and B 3  are lugs with a reduced width L 3 , which is for example approximately 1.2 mm. 
     In the example illustrated in the Figures, the three lugs B 1  to B 3  are lugs each delimited by two parallel and opposite edges, of longitudinal orientation in the case of the first lug B 1 , and of transverse orientation in the case of the second and third lugs B 2  and B 3 . 
     According to another aspect of the invention, means are provided for facilitating the breaking of the connecting lugs by manual operation with a view to detaching the minicard MC from the card C. 
     In accordance with the invention, the means constituting incipient breaks for the connecting lugs are grooves with particular profiles and dimensions. 
     With regard to the first lug B 1 , the front face  12  and reverse face  13  of the lug each have a groove  40 ,  42  which are opposite and aligned and each of which is shaped in cross-section, as can be seen in particular in FIGS. 3 and 5, with a substantially V-shaped profile. 
     More particularly, each groove  40 ,  42  has a vertical arm or edge  44 ,  46  which extends vertically perpendicular to the plane of the front face  12  and reverse face  13 , whilst the other edges or arms  48  and  49  are inclined in the direction of the card C, forming an acute angle with the edge  44 ,  46 , for example of approximately 300. The depths of the grooves  40  and  42  are preferably equal but they could be different and for example equal respectively to 0.42 and 0.30 mm in the case of a 0.82 mm thick card. Preferably, the apex of the groove is broken by a flat with a width of approximately 0.02 mm or in a substantially equivalent manner by a rounded part with a radius of curvature of approximately 0.01 mm. The residual section between the grooves depends on the thickness of the card and the nature of the material making up the support. The above values are given for a card made of injection-moulded ABS or ABS-HR (high temperature) and correspond to a residual section of approximately 0.10 mm. These values would however be substantially valid for cards obtained from another injection moulded material and with similar mechanical properties. 
     The grooves are produced by marking by means of a punch (not depicted in the figures) whose depth of penetration determines the depth of the grooves. 
     As can be seen in particular in FIG. 2, the grooves forming an incipient break  40  and  42  extend over the entire width L 1  of the lug  91 . 
     A description will now be given of the grooves forming an incipient break for the second and third lugs B 2  and B 3 . 
     In the example illustrated in the figures, the grooves  50  formed in the front face  12  of the lugs B 2  and B 3  are not identical to the grooves  52  formed in the reverse face  13 . They are on the other hand identical in pairs, that is to say the two grooves  50  formed in the front face  12  are identical, just like the two grooves  52  formed in the reverse face  13 . 
     As can be seen in particular in FIG. 2, the width of the grooves  50  is less than the total width L 3  of the first and second lugs B 2  and  33 . The same applies to the width of the grooves  52 . 
     The grooves  52  forming an incipient break which are formed in the rear face  13  are of a similar design to the grooves  40  and  42  formed in the first lug B 1 , that is to say each has a profile substantially in a V shape with an edge  54  perpendicular to the overall plane of the card C and an inclined edge  56 . The angle of the V is here for example 25° and the depth of the grooves  52  is 0.10 mm. The grooves preferably have a rounded corner at their end (at the apex of the V). By virtue of this rounded part, the initiation and propagation of cracks during the bending and torsion tests in accordance with the aforementioned ISO standard are limited. This  15  rounded part has in the example in particular a radius of curvature of around 0.01 mm. 
     On the other hand, the groove is sufficiently profiled to permit an incipient break by an intentional manual pressure acting on the minicard in the direction in particular from the front face to the reverse face. 
     The grooves  50  have a different profile substantially in the shape of a trapezium, illustrated notably in FIG.  7 . 
     Thus each groove  50  is delimited by a base  58  slightly inclined with respect to the front face  12  and to the overall plane of the card C, for example by an angle of 10°, which corresponds to the small base  58  of the trapezium, the latter also being delimited by a large side  60 , aligned with the edge  54  of the groove  52  opposite, which extends perpendicularly to the plane of the front face  12  and to the overall plane of the large card and, on the other hand, by a small side  62  which is inclined, the first side  60  being adjacent to the minicard MC whilst the inclined (or rather slightly rounded) side  62  extends in the direction of the body of the card C. The sides  60  and  62  are connected to the base  58  by fillets with a radius of approximately 0.05 mm. As can be seen in FIG. 8, the grooves  52  and  50  have a width L 4  which is for example equal to 0.40 mm whilst the width L 3  of the lugs B 2  and B 3  is equal to approximately 1.2 mm. The width of the groove  50  for its part is equal to approximately 0.22 mm. 
     This groove is shaped so as to resist the bending/torsion forces imposed by the aforementioned ISO standard, and this more so than the groove  52 . This is because its rounded and open shape is more resistant to the initiation of a crack than that of the groove  52 , which has an acute shape and ends in a small radius of curvature of for example 0.01 mm, as opposed to the groove  50  whose deepest end has for example a radius of curvature greater than 0.05 mm. 
     The presence of a radius of curvature at the end of the groove  52  is particularly justified in order to attenuate the tendency of this groove to initiate a crack during bending/torsion tests. 
     A slight inclination of the base  58  of the groove  50 , for example of 10 degrees, creates a zone situated closest to the end of the groove  52 . In this way a zone  69  where a crack is initiated or arrives is obtained, facilitating the breaking of the lug along a line joining the edges  60  and  54 . 
     Likewise, it can be seen in FIG. 8 that the groove  50  is more splayed than the groove  52 , this again for the purpose of being less sensitive to an incipient crack compared with the groove  52 . 
     Thus according to the invention the card is characterized in that it has lugs for connecting the minicard to the large card with a particular shape, each lug having two types of grooves opposite each other formed so as to be sufficiently resistant to the bending/torsion forces according to the ISO standard, one of the grooves however also being formed so as more easily to initiate a crack by intentional manual pressure on the minicard. Thus, if needed, the manual effecting of the breaking is controlled as close as possible to the minicard, whilst complying with the standardized contour of the minicard. 
     Where necessary, it is possible to have a single lug of this type connecting the minicard to the large card and sized so as to fulfill the mechanical function of several lugs. 
     Where the removal of the minicard is not required, it is possible to have a large-format card in accordance with the ISO standard both with regard to the dimensions and the properties of mechanical strength. 
     In accordance with another embodiment illustrated in FIG. 9, the lug B 1  is produced as two lugs B 4 , B 5  spaced apart, situated notably close to the corners  70 ,  71  of the minicard. These lugs can have grooves whose cross-section is substantially in accordance with that of the lug B 1  (FIG.  5 ). 
     The advantage of a construction with two lugs is to make it possible to keep the minicard substantially in one plane in spite of a curvature of the card in its width. In this way a probable tendency of the lug B 1  to have an incipient crack from the corners  70 ,  71  is avoided. 
     It is however preferred to have lugs B 4 , B 5  in conformity with the lugs B 2 , B 3  in order to increase the resistance to the bending/torsion forces. 
     Alternatively, in order to have the least deformation on the minicard, it may be envisaged having a single lug with a structure substantially in accordance in particular with that of B 1  but less wide, and centered on the longitudinal median of the minicard. Preferably this central lug can be in accordance with B 4 , B 5  and sized so as to fulfil the required function. 
     The additional function of the lug B 1 , which is to facilitate the passage of resilient connector blades, can be achieved in two other different ways. 
     The first is illustrated in FIGS. 9 and 10, by chamfers which attenuate the discontinuity caused by the slot F. The chamfers are provided at the level of the passage of these resilient blades in the case of significant discontinuity. In the example, a chamfer ( 72 ,  73 ) is provided respectively on each side of the slot F. 
     As a variant, the above function is achieved in accordance with FIGS. 11 and 12. Between the two lugs B 4 , B 5  there is a slot  74  passing through the card equivalent to the slot F but narrower. It can result from a shearing operation effected by blades or by punch and die. 
     Also as a variant, the slot F can be produced in accordance with the notch  74  in FIG. 12 over the entire contour of the minicard with the exception of the lugs. 
     The invention is not limited to the embodiment which has just been described. 
     Without departing from the scope of the invention, but preserving the principle of the invention, it is of course possible to modify the dimensions, position and number of the different lugs slightly, as well as the profiles and dimensions of the grooves. 
     In all cases, the design in accordance with the teachings of the invention makes it possible to meet the criteria of mechanical strength of the card without separation of the minicard, permits manual separation of the minicard MC without leaving any harmful burrs, and makes it possible to prevent premature wear on the connectors in particular when it is the large card as a whole which is used.