WO2015097400A1

WO2015097400A1 - Electronic device, such as a card, comprising contact means arranged in hairpins and process for manufacturing such a device

Info

Publication number: WO2015097400A1
Application number: PCT/FR2014/053517
Authority: WO
Inventors: Elodie GRAGNIC; Ahmed Ali; Mathieu GARCON
Original assignee: Oberthur Technologies
Priority date: 2013-12-23
Filing date: 2014-12-22
Publication date: 2015-07-02
Also published as: FR3015733A1; FR3015733B1

Abstract

The invention relates to an electronic device designed to communicate by contact and at distance via the antenna (12) connected electrically to the microcircuit by way of a contact means, at each of its ends. At least one contact means (26a, 26b) consists of a wire arranged to form a hairpin defining consecutive lines (32) directed alternatively in opposite directions, the lines being connected to each other by a bend, the contact means (26) comprising a portion lying flush with the bottom of the cavity and an embedded portion comprising at least one first bend (34) arranged outside of the cavity, the module being fastened in the cavity by means of a conductive anisotropic adhesive designed to connect electrically the contact pads of the module to the contact means.

Description

Electronic device, such as a card, comprising contact means arranged in laces and method of manufacturing such a device

The invention relates to an electrical device in the field of microcircuit cards.

More particularly, the invention relates to electronic devices such as microcircuit cards and more particularly to dual cards comprising at least one module provided with copper or other material contacts adapted to come into physical contact with probes of a terminal, and a antenna adapted to communicate with a remote terminal.

Such a microcircuit card generally comprises a module comprising a microcircuit, a card body comprising a cavity adapted to receive the module, an antenna formed of a conductive wire embedded in the card body, the antenna being electrically connected to the microcircuit by via a contact means made flush with the bottom of the cavity.

The present invention is particularly concerned with improving the electrical connection between the antenna and the microcircuit. More particularly, the invention relates to an electronic device comprising contact communication means and remote communication means, the device comprising a body comprising a cavity comprising a bottom and adapted to receive a module, the module being adapted to communicate by contact and comprising a microcircuit, an antenna adapted to communicate remotely and formed of a conductive wire extending between two ends, the antenna being electrically connected to the microcircuit via a contact means, to each of its ends.

It is known from document EP 1 021 792 to produce a contact means by arranging a conducting wire according to a zigzag shape so that the zigzag portion provides a contact area for electrically connecting the module contacts. For this purpose the zigzag portion opens into a well formed in the cavity made in the card body. The zigzag portion opening at the bottom of the well is disposed substantially opposite the module studs dedicated to the antenna. These pads are made on the inner face of the module and are connected to the microcircuit. A conductive element, such as a polymer bump, provides the electrical connection between the zigzag portion and the pad of the module. It is also known from US 20130075134 a contact means having a coil-shaped wire, that is to say a sinuous shape so that the coil develops while moving away, in every point, from the end of the antenna.

It has been sought a solution to improve the mechanical attachment of the module in the card body.

For this purpose, the present invention proposes a microcircuit device of the type described above and in which at least one contact means consists of a wire electrically connected to one end of the antenna, and arranged so that the wire develops. from the end of the antenna by drawing a lace defining consecutive lines directed alternately in opposite directions, and being further away from the end of the antenna than the line preceding it and the lines being interconnected by a detour, the contact means having a flush portion at the bottom of the cavity and an embedded portion having at least a first detour disposed outside the cavity, the module being fixed in the cavity by means of a conductive anisotropic adhesive adapted to connect electrically the contact pads of the module to the contact means.

Thanks to these provisions the electrical connection zone is also an adhesion zone between the module and the card body, which ensures a larger surface for fixing the module in the card body and improves the durability of the card. it faces external constraints, such as mechanical stress, temperature and humidity.

In addition at least one detour orienting the wire in a first direction is embedded in the card body thus preventing the contact between the cutter and said detour, and thus reducing the risk of cutting the detour. Moreover, thanks to these provisions, the milling cutter firstly produces the distal lines of the end of the antenna, that is to say the peripheral lines, thus reducing the risk of cutting the proximal lines embedded in the map body, whatever the direction of arrival of the antenna.

According to other characteristics

the detour has a width and the interval between two lines connected by a detour is less than the width of the detour;

- The first detour directs the wire in a first direction, and wherein the device comprises at least one second detour directing the wire to a second direction opposite to the first direction and disposed outside the cavity;

each line extends in at least two different directions;

all the detours of a contact means are disposed outside the cavity beyond the edge delimiting in the cavity, on either side of the end of the antenna wire; the lines are curved and have a U shape;

the lines have a U shape at right angles;

the interval measured between the lines in the first direction is less than the interval measured between the lines in the second direction;

the lines of a contact means have a substantially similar shape to each other;

the contact means is formed by the wire of the antenna;

- The device is a bank format card, whose dimensions are 85mm * 54mm * 0.76mm;

the cavity has a step delimiting an upper cavity and a lower cavity, the step being adapted to receiving in support the module comprising the anisotropic adhesive, and wherein the contact means has a portion formed flush over the entire width of the step, the other portion being embedded in the card body beyond the cavity.

The invention also relates to a method of manufacturing a card comprising the following steps: continuously depositing on the plastic layer a wire to successively form a first contact means, at least two turns forming the antenna and a second contact means, the contact means being constituted by a wire electrically connected to one end of the antenna 12, and arranged so that the wire develops from the end of the antenna, located in outside the cavity beyond a first edge delimiting it, by drawing a lace defining consecutive lines directed alternately in the opposite direction, each line being further from the end of the antenna than the line preceding it and being connected to it by a detour, lamination of at least several layers of plastics with the layer comprising the wire, machining in the body of a cavity perpendicular to the contact means so as to make at least two lines of the contact means, so that the contact means comprises a portion flush with the bottom of the cavity and a portion embedded with at least a first detour disposed outside the cavity, deposits an anisotropic adhesive on the module, insertion, in the cavity, of a module comprising contact pads so that the contact pads are facing the contact means, application of a compression so as to electrically connect the contact means to contact pads of the module.

According to a variant, during the machining step, the cutter is moved so as to first machine the peripheral lines of the contact means. The present invention will be better understood on reading the following description made with reference to the appended figures in which:

FIG. 1 is a schematic view of a card according to the present invention,

FIG. 2 represents a detail view of FIG. 1

FIG. 3 represents an alternative embodiment of the device according to the invention,

FIG. 4 represents a detailed view of a second embodiment of the invention,

FIG. 5 illustrates a third embodiment of the invention;

FIG. 6 is an exploded view of the device according to the invention.

The following description is made on the basis of the accompanying drawings which are taken by way of example and are in no way limiting.

The present invention is in the field of electronic devices and more particularly microcircuit cards having at least one antenna 12. The present invention addresses the problem of the electrical connection of the microcircuit with an antenna 12 embedded in the body 14 of the card.

Microcircuit cards are commonly used as a bank card, identity card, loyalty card, social insurance card or as a telephone subscription card.

The card 10 comprises a body 14 formed of a thin plastic plate, for example PVC, or a polycarbonate plate. Its thickness is negligible compared to its dimensions in width and length. The shape, thickness and outer contour of the plastic plate is defined by the ID-1 standard specified in ISO / IEC 7810. Such a card has the dimensions 85mm * 54mm * 0.76mm. Such a body 14 is made by any method, for example by hot rolling of plastic layers. The layers have various functions. Thus, a central inner layer or substrate may be a structural layer giving the body 14 and the card its rigidity. Intermediate layers, on both sides of the substrate, may comprise inscriptions or decorations with an informative or decorative function. External layers, advantageously transparent, complete the stacking and provide surface protection of the more internal layers.

It is known to make a microcircuit card by assembling a module comprising a microcircuit on its inner face in the body 14 of plastic. The microcircuit includes a microcontroller and memory. This memory is secure in that it can only be accessed via the microcontroller.

A cavity 16 is formed in the body 14 of the card. It is delimited by four substantially perpendicular edges. It is adapted to accommodate the module on which the microcircuit is mounted. It is performed in accordance with the specifications of the ISO / IEC 7816 standard which defines the position of the module accommodated in the cavity 16 with respect to the longitudinal and lateral edges 18 of the card.

The microcircuit is adapted to interact with a reader or an external terminal. This can be done with or without contact. The communication can be in contact and the module then comprises a contact plate electrically connected to the microcircuit, disposed on the outer surface of the module so as to end up on the surface of the card, where it can be in contact with probes. a reader. The communication can also be contactless. An antenna 12 is then electrically connected to the microcircuit. A reader then comprises a homologous antenna 12 adapted to exchange with the antenna 12 of the card. The microcircuit can offer both interface modes, with and without contact. It is then called dual and includes a contact plate and an antenna 12. Such an antenna 12 is formed of a winding having several turns. The antenna 12 is unwound and embedded or deposited on an inner layer then covered by the other layers and then laminated with these layers

The antenna 12 comprises at least one, generally two, end 24a, 24b which must be electrically connected with the microcircuit via contact pads disposed on the inner face of the module, and themselves connected to the microcontroller by wires conductors. A contact means 26a, 26b makes it possible to make an electrical contact between an end 24a, 24b of the antenna 12 and the microcircuit via the contact pad. For this at least a portion of the contact means 26a, 26b opens into the cavity 16 from an edge 36a, 36b located in the vicinity of the end of the antenna 24a, 24b and is flush with the bottom of the cavity. The contact means 26 is thus at least partially accessible for making an electrical connection. The contact means 26a, 26b and the contact pad of the module are arranged facing so as to obtain a large electrical connection area. A conductive adhesive (referenced 27 in Figure 6 described below) is deposited between the contact means 26 and the contact pad to provide the electrical connection.

The realization of the cavity, for example by milling, at the same time as it forms the cavity 16 able to accommodate a module, will make accessible a part of the contact means. In addition, advantageously, this operation can prepare said contact means 26a, 26b by stripping it on the surface in order to rid it of a possible sheath of insulating material.

As visible in the accompanying figures, the cavity 16 has a step 28 defining an upper cavity 16a and a lower cavity 16b deeper. The upper face of the step 28 forms the bottom of the upper cavity 16a and is adapted to receive the module in support. The contact means are made flush with the bottom of the upper cavity 16a and arranged vis-à-vis the contact pads of the module. The contact means consist of a wire which extends the wire of the antenna 12 and is arranged in a particular arrangement which will be detailed in the following description. The extension of the antenna 12 ensures a continuity of the electrical connection between the antenna 12 and the contact means. According to a preferred embodiment, the contact means are constituted by the wire of the antenna 12.

The contact means 26a, 26b extends between a first end merged with the end 24a, 24b of the antenna 12 and a second free end 25a, 25b, in a particular pattern. The wire of the contact means 26a, 26b is arranged to extend the wire of the antenna and lead into the cavity from an edge 36a, 36b delimiting the cavity 16. As can be seen in the accompanying figures, the wire presents a yaw pattern, that is to say that the yarn is deposited so as to draw a set of consecutive lines 32 directed alternately in the opposite direction. In addition, each line 32b is further from the end 24a, 24b of the antenna 12 than the line 32a preceding it. Two lines 32a, 32b consecutive are interconnected by a detour 34, formed by the turn that the wire draws to guide the consecutive line 32b to a direction opposite to the first direction of the line preceding 32a. Each line 32b is made in a pattern substantially similar to the preceding line 32a.

At least one detour 34, orienting the wire in a first direction, is disposed outside the cavity beyond the edge 36a, 36b situated in the vicinity of the end of the antenna and from which the wire of the contact means terminates in the cavity .

The contact means 26 is made so that at least one detour 34 directing the wire towards the second direction is also disposed outside the cavity, beyond the edge 36a, 36b from which the wire ends in the cavity.

According to a preferred embodiment, all the detours 34 orienting the line in a first direction and the detours 34 orienting the lines 32 in the second direction are arranged outside the cavity 16 and are embedded in the body 14 of the card. Advantageously, the detours 34 are disposed on either side of the end 24a, 24b of the antenna, beyond the edge 36a, 36b. As shown, a portion of the contact means 26 is flush with the surface of the upper cavity 16a and another portion of the contact means 26 including the detours 34 is embedded in the body 14 in the extension of said surface.

The fact of drowning a part of the contact means 26a, 26b in the body 14 protects all the detours 34 and thus avoid tearing them.

In Figures 1 to 4 attached, showing a preferred embodiment, each line extends in at least two different directions, that is to say is not rectilinear. The lines 32 extend in two substantially perpendicular directions and have a U-shaped curved shape (FIG. 4) or a U-shaped shape at right angles (FIGS. 1 to 3), that is to say formed from lines 32 arranged perpendicularly .

A line 32b has a length greater than the line 32a preceding it and is disposed further from the end 24a, 24b of the antenna 12. It follows that each line opening into the cavity 16 is circumscribed by the edge 36a, 36b delimiting the cavity 16 beyond which are embedded the detours 34 and the line which is consecutive thereto, except the distal line of the end 24a, 24b of the antenna 12.

It emerges from the above provisions that, irrespective of the direction of arrival of the cutter on the contact means 26 in the plane in which the contact means opens, the latter will first machine the most peripheral lines 32b. remote from the end 24a, 24b of the antenna 12, thereby considerably reducing the risk of tearing lines 32a located near the end 24a, 24b of the antenna 12. These provisions thus guarantee a better card production rate for which the electrical connection between the antenna 12 and the contact means 26a, 26b is effective.

As illustrated in Figure 4, the interval between each line is constant. It is for example equal to the width of the detour. In order to provide the largest density of conductive material possible, it is desired a layout of the lines 32a, 32b successive as close as possible. Thus, by way of indication, always with a sheathed copper wire having a useful cross section with a diameter of between 120 μm and 200 μm, preferably 145 μm, the interval 38 between two lines is as small as possible and at least less than 200 μm. These arrangements are particularly advantageous when an anisotropic adhesive is used to fix the module in the cavity and simultaneously make the electrical connection. Indeed such an adhesive has conductive particles in one direction, it is necessary to ensure a sufficient connection surface between the particles of the adhesive and the wire forming the connection means.

According to an alternative embodiment illustrated in FIGS. 1 to 3, the lines 32 have a U-shape at right angles. These arrangements have the advantage of being able to deposit the antenna 12 more easily and more precisely. In addition, these provisions make it possible to easily and precisely modify the interval 38 between each line 32a, 32b. According to a preferred variant of the invention, the gap 38 is narrowed between the lines 32a, 32b accessible from the bottom of the cavity and intended to receive the conductive material, such as an anisotropic adhesive, allowing the connection to the contact pad microcircuit.

The interval 38 measured between the lines 32a, 32b which extend in a first direction has a width e2 smaller than the interval 38 measured in the second direction, of width el. With these provisions, it is possible to deposit a greater amount of conductive wire on the width 1 of the step 28, ensuring a larger electrical contact area.

As an indication, for a cavity 16 having dimensions of 13.2 x 12 mm, the lower cavity 16b has dimensions of 8.5 x 8.5mm, centered on the cavity, the contact means 26a, 26b is flush with the entire width 1 of the step 28. Thus the accessible contact means 26 advantageously covers a sufficient surface to ensure good electrical contact, even if only the other part is disposed beyond the cavity. This advantageously makes it possible to perform the machining which makes the contact means 26 appear and superficially strip in a single milling pass, which is preferable, in order to limit the risk of tearing off.

According to an alternative embodiment not shown, the lines extend in two substantially perpendicular directions and have an L shape. The first detour orients the wire in a first direction, and the second detour directs the wire towards a second direction opposite to the first one. direction and is disposed outside the cavity beyond a distinct edge, here perpendicular to the edge from which opens the wire in the cavity.

The present invention also proposes the advantage of producing two contact means by continuously depositing a wire forming the first contact means, the antenna 12 and the second contact means, without the risk of crisscrossing the wire. Thanks to these provisions, the two contact means extend in the same plane in which the machining cutter is moved during the production of the cavity. The flatness of the contact means reduce the risk of cutting the wire forming the contact means. The contact means are made symmetrical with respect to a median plane of the cavity.

According to an embodiment illustrated in FIG. contact means is constituted by the lines 32 flush with the bottom of the upper cavity and detours 34 embedded, the lines being arranged so that the interval 38 between them has a width e2 less than the width e3 of a detour 34. These provisions impose to offset detours relative to each other as shown in Figure 5 attached.

The method comprises the following steps. The first contact means 26a, the antenna 12 formed of several turns 22 and the second contact means 26b are embedded in a plastic layer according to methods known to those skilled in the art. The card body 14 is then manufactured by laminating the plastic layer in which the antenna 12 and the other plastic layers constituting the card are embedded. The contact means are disposed in a plane coinciding with the bottom of the upper cavity 16a so as to come flush with the bottom of the upper cavity 16a after the machining step.

Advantageously, during the machining step, the cutter is moved so as to first machine the peripheral lines of the contact means.

The method further comprises a machining operation to realize the cavity. The machining makes it possible to remove the plastic layer covering the contact means, and expose the copper wire forming the contact. The machining is therefore precise enough to remove the plastic sheath covering the copper wire and an upper portion of the copper wire. Preferably 25% to 75% of the yarn is machined in section so as to obtain the largest contact area possible. The diameter of the wire being 145μιη, it will be understood that the machining must be performed in a very limited window. The next step is to set up the module in the cavity 16 provided for this purpose. The module has a rim covered with an anisotropic adhesive and which will bear against the rim of the upper cavity. After compressing the module against the edge of the upper cavity 16a, the contact pads of the module are electrically connected to the contact means.

Today, the current machining process has precise adjustment parameters (depth, speed, direction) with a tolerance of 40μπι or even ΙΟΟμηι. The performance of the current machines, does not allow to obtain a better precision.

It was therefore sought a solution to improve the tear resistance of the antenna pad 12 during the machining step to prevent tearing of the wire and any break in connection between the antenna 12 and the microcircuit, while providing a reliable connection.

In Figure 6, there is shown by an exploded view a device according to the invention. The same references have been used to designate elements similar to those of the preceding figures.

As can be seen in this figure, an anisotropic conductive adhesive 27 is placed between the contact means 26 and a module 40. The anisotropic conductive adhesive 27 extends within the step, which makes it possible to obtain good fixation. mechanical.

Claims

1. Electronic device comprising means of contact communication and means of remote communication, the device comprising:

a body (14) comprising a cavity (16) comprising a bottom and adapted to accommodate a module,

the module being adapted to communicate by contact and comprising a microcircuit,

an antenna (12) adapted to communicate remotely and formed of a conductive wire extending between two ends (24a, 24b), the antenna (12) being electrically connected to the microcircuit via contact means , at each of its ends,

At least one contact means (26a, 26b) consists of a wire electrically connected to one end (24a, 24b) of the antenna (12), and arranged so that the wire extends from the end (24a, 24b) of the antenna (12) by drawing a yaw defining consecutive lines (32) directed alternately in opposite directions, and being further from the end (24a, 24b) of the antenna (12) than the line preceding it and the lines being connected together by a detour,

the contact means (26) comprising a part flush with the bottom of the cavity and a embedded part comprising at least a first detour (34) disposed outside the cavity,

characterized in that

the module is fixed in the cavity by means of a conductive anisotropic adhesive adapted to electrically connect the contact pads of the module to the contact means.

2. Device according to the preceding claim, in which the detour (34) has a width and the interval between two lines (32) connected by a detour is less than the width of the detour (34).

3. Device according to one of the preceding claims, in which the first detour orients the wire in a first direction, and in which the device comprises at least a second detour orienting the wire towards a second direction opposite the first direction and arranged outside of the cavity.

4. Electronic device according to one of the preceding claims, wherein each line (32) extends in at least two different directions.

5 Device according to the preceding claim in which all the detours (34) of a contact means are arranged outside the cavity beyond the edge (36) delimiting in the cavity (16), on either side of the end (24a, 24b) of the antenna wire (12).

6 Device according to one of the preceding claims, in which the lines (32) are curved and have a U shape.

7. Device according to one of the preceding claims, in which the lines (32) have a U shape at right angles.

8. Device according to one of claims 4 to 7, wherein the interval (38) measured between the lines (32) in the first direction is less than the interval (38) measured between the lines in the second direction.

9. Device according to one of the preceding claims, wherein the lines (32) of a contact means have a substantially similar shape to each other.

10. Device according to one of the preceding claims, wherein the contact means (26) is formed by the wire of the antenna (12).

11. Device according to one of the preceding claims, characterized in that it is a card (10) of bank format, the dimensions of which are 85mm * 54mm * 0.76mm.

12. Device according to one of the preceding claims, in which the cavity has a step (28) delimiting an upper cavity (16a) and a lower cavity (16b), the step (28) being adapted to receive in support the module comprising the anisotropic adhesive, and in which the contact means has a part made flush over the entire width (1) of the step, the other part being embedded in the card body beyond the cavity (16).

13. Method for manufacturing a card (10) according to one of the preceding claims, characterized in that it comprises the following steps:

- Continuously deposits a wire on the plastic layer to successively form a first contact means, at least two turns (22) forming the antenna (12) and a second contact means, the contact means (26) consisting of a wire electrically connected to one of the ends (24a, 24b) of the antenna 12, and arranged so that the wire develops from the end (24a, 24b) of the antenna ( 12), located outside the cavity beyond a first edge delimiting it, by drawing a lace defining consecutive lines (32) directed alternately in opposite directions, each line being further from the end (24a, 24b ) of the antenna (12) than the line preceding it and being connected to it by a detour,

- Lamination of at least several layers of plastics with the layer comprising the wire, Machining in the body of a cavity (16) perpendicular to the contact means so as to make accessible at least two lines (32) of the contact means, so that the contact means (26) comprises a part flush with the bottom of the cavity and an embedded part comprising at least one first detour (34) arranged outside the cavity

- Deposition of an anisotropic adhesive on the module,

- Insertion, into the cavity, of a module comprising contact pads so that the contact pads face the contact means (26),

application of compression so as to electrically connect the contact means (26) to the contact pads of the module.

14. Method according to the preceding claim, in which, during the machining step, the cutter is moved so as to first machine the peripheral lines of the contact means.