Contactor for thin plastic card

0001The present invention relates to an electrical contactor for a thin plastic card, such as a microcircuit card.

0002In the field of microcircuit cards, it is advantageous to place an electric contactor in the thickness of a thin plastic support card in order to be able to control a function. This electric switch is typically actuated by a support, for example digital, on a determined area of ​​the thin plastic card.

0003It is known to make an electric contactor in a thin plastic card by means of an insert incorporated in said thin plastic card, as one of the constituent layers, assembled by rolling. Given the conditions of pressure and rolling temperature, it is difficult to roll clean and safe such inserts. Moreover, such an embodiment leads most often to an electric contactor appearing in overthickness and therefore visible and unveiling the presence of such an electrical contactor and its location, which is to be avoided for security reasons. The document "<patcit id="pcit0001" dnum="FR2949639A1"><text>FR 2 949 639 A1</text></patcit>"discloses an electrical contactor and its manufacturing method according to the preamble of claim 1 and 9.

0004The present invention overcomes these various disadvantages by providing an electric switch incorporated after the rolling step, in a thin plastic card and substantially invisible manner.

0005The subject of the invention is an electrical contactor for a thin plastic card comprising two terminals and a conducting element able to move relatively so as to occupy a first position where the two terminals are isolated, or a second position where the conductive element carries out a contact between the two terminals, the two terminals being secured to an elastically deformable membrane, to allow movement from the first position to the second position under the effect of a support and an automatic opposite movement, when said support ceases.

0006According to the invention, the conductive element comprises a capsule, substantially hemispherical, whose concavity faces the two terminals.

0007According to another characteristic of the invention, the capsule is disposed in a cavity made in the thickness of the thin plastic card and the elastically deformable membrane closes the cavity.

0008According to another characteristic of the invention, the axis of the capsule is substantially perpendicular to the elastically deformable membrane.

0009According to another characteristic of the invention, the terminals are arranged, relatively to the axis of the capsule, substantially symmetrically to one another.

0010According to another characteristic of the invention, the capsule is shaped such that a height, measured between the top of the capsule and the right of a terminal, is greater than a height of a terminal relative to the elastically deformable membrane.

0011According to another characteristic of the invention, the capsule is elastic and can take a free form in the absence of support and a shape compressed under the effect of a support.

0012According to another characteristic of the invention, a height, measured between the top of the capsule and the right of a terminal, is less than a height of a terminal relative to the elastically deformable membrane, when the capsule is in its shape. compressed.

0013According to another characteristic of the invention, the capsule comprises a nipple at its top.

0014The invention also relates to a method for manufacturing a contactor for a thin plastic card comprising the following steps: machining a cavity in the thickness of the thin plastic card, depositing a conductive element in the cavity, making two terminals in an elastically deformable membrane by positive or negative etching, closing the cavity by placing and bonding the elastically deformable membrane.

0015According to another characteristic of this method, the conductive element comprises a substantially hemispherical capsule whose concavity faces the two terminals.

0016According to another characteristic of the invention, the capsule is shaped such that a height, measured between the top of the capsule and the right of a terminal, is greater than a height of a terminal relative to the elastically deformable membrane.

0017According to another characteristic of the invention, the capsule is elastic and can take a free form in the absence of support and a compressed form under the effect of a support.

0018According to another characteristic of the invention, a height, measured between the top of the capsule and the right of a terminal, is less than a height of a terminal relative to the elastically deformable membrane, when the capsule is in its shape. compressed.

0019According to another characteristic of the invention, the capsule comprises a nipple at its top.

0020Other characteristics, details and advantages of the invention will emerge more clearly from the detailed description given below as an indication in relation to drawings in which:<ul><li>the <figref idref="f0001">figure 1</figref>, respectively <figref idref="f0001">figure 2</figref>, shows, in sectional view, an electric contactor according to a first embodiment, in the open position, respectively in the closed position,</li><li>the <figref idref="f0002">figure 3</figref> represents, in sectional view, an electric contactor according to a second embodiment, in the open position,</li><li>the <figref idref="f0002">figure 4</figref> represents, in a sectional view, the electrical contactor of the <figref idref="f0002">figure 3</figref>in a first closed position,</li><li>the <figref idref="f0003">figure 5</figref> represents, in a sectional view, the electrical contactor of the <figref idref="f0002">figure 3</figref>in a second closed position,</li><li>the <figref idref="f0004">figure 6</figref>, respectively <figref idref="f0004">figure 7</figref>, shows, in profile cutaway view, an electric contactor according to a third embodiment, in the open position, respectively in the closed position.</li></ul>

0021It may be useful to have an electrical contactor 1 in a thin plastic card 10. A thin plastic card 10 designates a card made of plastic, substantially flat, and whose dimensions in the plane are of the order of a few tens of millimeters for a thickness of the order of a millimeter. Such a thin plastic card 10 can serve as a support for a microcircuit card. Such a thin plastic card 10 is for example defined by the ISO 7810 standard. Such a microcircuit card can be used as a bank card, identity card or telephone subscription card or any other equivalent application.

0022An electric switch 1 can in such a frame serve to control a function. The electric switch 1 can thus, for example, make an opening / closing of an antenna loop. Thus said antenna loop is activated when the electric switch 1 is closed. In the case of a microcircuit, such an antenna loop can be used to supply energy to said microcircuit by induction. Such a power supply makes it possible to "wake up" the microcircuit which can then begin the execution of its resident program. The presence of an electric switch 1 to control this power function ensures that the microcircuit is activated voluntarily and not as soon as it is within range of an induction power supply.

0023An electrical contactor 1 can still be interfaced with a microcircuit to which it then provides a logical state information, a function of the open or closed position of the electric switch 1. Such a state, can thus allow, from the outside, to modify the progress of the microcircuit program. It is still possible to have several such electrical contactors 1 on the same card 10.

0024Such an electric contactor 1 typically comprises two terminals 2 making it possible to connect it, as a dipole, to an electric circuit and a means of selectively making or not making an electrical contact between these two terminals 2, so as to selectively open or close said circuit electric. This means can, according to a type of contactor, comprise a conductive element 3. The terminals 2 and said conductive element 3 are able to move relative to each other between two positions 11, 12. In a first position 11 , where the electric switch 1 is said to be open, the two terminals 2 are electrically isolated. In a second position 12, where the electric contactor 1 is said to be closed, the conductive element 3 makes an electrical contact between the two terminals 2, which are then electrically connected.

0025According to an embodiment more particularly illustrated in the <figref idref="f0001">figure 1</figref> in open position 11 and at the <figref idref="f0001">figure 2</figref> in the closed position 12, the electric contactor 1 is characterized in that the two terminals 2 are integral with an elastically deformable membrane 4.

0026This elastically deformable membrane 4 is for example made of plastic. This advantageously makes it possible to provide electrical isolation between the two terminals 2.

0027Such a plastics material can also advantageously produce a deformability characteristic which thus allows movement from the first position 11, illustrated in FIG. <figref idref="f0001">figure 1</figref>, to the second position 12, illustrated in the <figref idref="f0001">figure 2</figref>. This displacement allows a mobilization of the terminals 2 which can come into simultaneous contact with the conductive element 3, and thus make the electrical contact between the two terminals 2.

0028The deformability of said membrane 4 is still advantageously elastic so that it can spontaneously return to a rest position.

0029A rest position is for example illustrated at the <figref idref="f0001">figure 1</figref> where it corresponds to an open position 11. A support 13 applied to the membrane 4, in cooperation with a free space 5 under said membrane 4, allows deformation of the membrane 4 to reach a closed position 12 of the <figref idref="f0001">figure 2</figref>, bringing the two terminals 2 in contact with the conductive element 3. The membrane 4 being elastic, spontaneously and automatically returns to the rest position 11 when the support 13 ceases.

0030It is thus realized an electric contactor 1 monostable, opened by default, also called normally open.

0031The support 13 effecting the deformation of the membrane 4 and the change of position of the contactor 1 is made by any means or tool. However, it is advantageously sized to be realized with a finger.

0032The embodiment of the plastic membrane 4 advantageously makes it possible to integrate such a membrane 4 as an additional partial or complete layer of a thin plastic card 10.

0033This is particularly advantageous in that it is thus possible to completely confuse and align the membrane 4 with the external surface of the card 10. This advantageously makes it possible to make the electric switch 1 completely undetectable, at least visually, which adds to the security of the commanded function.

0034The membrane 4 may be made of any plastic material. Preferably, the polyethylene terephthalate PET is particularly adapted to the elastic deformability needs of the membrane 4. In addition, the PET assembles very well by gluing or welding with all the materials usually envisaged to make a thin plastic card. 10.

0035The two terminals 2 have any shape. They are preferably, relative to the membrane 4, slightly projecting in the direction of the conductive element 3.

0036The conductive element 3 is at least conductive between the two contact points 3b respectively with the two terminals 2. For this it can be made of metal material, covered plastic material, at least between the two contact points 3b with the two terminals 2 of a continuous conductor, such as, for example, an etched track or a metallization, either at the surface or in the mass of the element 3.

0037According to the invention, the conductive element comprises a substantially hemispherical capsule 3, whose concavity 3a faces the two terminals 2.

0038According to an advantageous embodiment, the conductive element 3 is disposed in a cavity 5 made in the thickness of the thin plastic card 10. The elastically deformable membrane 4 then serves as a closure and closes the cavity 5 while maintaining the conductive element 3 in place. The outer surface of the membrane 4 merges advantageously, in that it is aligned with or replaces, the outer surface of the thin plastic card 10.

0039Advantageously, the axis 7 of said capsule 3 is substantially perpendicular to the membrane 4.

0040Advantageously, the terminals 2 are arranged, relatively to the axis 7 of the capsule 3, substantially symmetrically to one another. Such an arrangement advantageously allows simultaneous contact of a first terminal 2 with the capsule 3 and a second terminal 2 with the capsule during a support 3.

0041For the same reasons, the capsule 3 is advantageously symmetrical. The axis 7 is then an axis of symmetry for said capsule 3.

0042According to a preferred embodiment, the capsule 3 has a shape of revolution about the axis 7. The axis 7 is then an axis of revolution for the capsule 3.

0043As illustrated in <figref idref="f0001">Figures 1 and 2</figref>capsule 3 does not necessarily occupy the entire height of cavity 5.

0044As illustrated in <figref idref="f0002">Figures 3, 4</figref> and <figref idref="f0003">5</figref>capsule 3 does not necessarily occupy the entire width of cavity 5.

0045In the two previous cases, in order to prevent any movement of the capsule 3, which may risk placing it in a position where it could no longer come into contact with the terminals 2, the capsule 3 can be fixed, for example by gluing, in the cavity 5.

0046According to an advantageous embodiment, the dimensions of the capsule 3 are substantially of the same order as the dimensions of the cavity 5, in order to avoid having to resort to such a fixation, while allowing a movement of the capsule 3, in a measure that does not jeopardize its function as a conductive element. 3. All the examples illustrated in <figref idref="f0001 f0002 f0003 f0004">Figures 1-7</figref> satisfy this requirement. Thus the step of placing the conductive element 3 in the cavity 5 is limited to a deposition of said conductive element 3.

0047According to another advantageous characteristic, more particularly illustrated with the embodiments of the <figref idref="f0002 f0003">figures 3-5</figref> and <figref idref="f0004">6-7</figref>the capsule 3 is shaped in a particular way. In this way, the capsule 3 has, at its top 6, a protuberance adapted to come into contact with the inner wall of the membrane 4. This protuberance has a dimension 8 measured in a direction parallel to the axis 7 greater than the height 9 of a terminal 2 in excess relative to said inner wall of the membrane 4. The height 8 is measured between a plane parallel to the inner wall of the membrane 4 passing through the top 6 of the capsule and a point 3b, at right of a terminal 2, where a terminal 2 comes into contact with the capsule 3.

0048Thus, even in the case where the capsule 3 is not fixed in the cavity 5, and where its height is less than the depth of the cavity, which allows a certain vertical movement of the capsule 3 in the cavity 5, the protuberance formed at the top 6 of the capsule 3 is adapted to come into contact, along the axis 7, with the inner wall of the membrane 4, and before one of the terminals 2 come into contact at point 3b with the capsule 3. A contact at point 3b is not possible as long as the membrane 4 remains flat. Such contact between terminals 2 and capsule 3 requires at least one deformation of the elastically deformable membrane 4.

0049Such deformation of the membrane 4 can then be performed around the top 6 of the capsule 3, as illustrated in FIG. <figref idref="f0002">figure 4</figref>, in order to allow each of the terminals 2 to come into contact with the capsule 3 on each of its sides.

0050Such deformation of the membrane 4 can still, as illustrated in FIG. <figref idref="f0003">figure 5</figref>, accompanied by a deformation of the capsule 3, which thus contributes to facilitating the making of a contact between the two terminals 2 via the capsule 3.

0051According to an important characteristic of the present invention, the capsule 3 is elastically deformable. In contrast to the membrane 4 which is continuously deformable, the deformation of the capsule 3 is preferably bistable and comprises two preferred extreme shapes. A first form comprises a free form 14, stable, corresponding to a rest state of the capsule 3, is obtained in the absence of stress exerted on the capsule 3 and in particular in the absence of a support 13. A second form comprises a compressed form 15, corresponding to a constrained state of the capsule 3, is obtained under the effect of a support 13, typically in the direction of the axis 7.

0052Two examples, showing two corresponding free 14 and compressed forms of the same capsule 3, are presented compared to the <figref idref="f0003">figure 5</figref> and separately to <figref idref="f0004">Figures 6-7</figref>.

0053The advantages of a capsule 3 having a bistable deformation in two forms 14, 15 are multiple.

0054Given the thickness of the electric contactor 1, less than the thickness of a thin plastic card 10, of the order of a few millimeters, and preferably between 0.5 and 1 mm, it is difficult to perceive a movement of the membrane 4 under the effect of the support 13 exerted by a finger and therefore to know if the electric switch 1 is actually closed or not. On the other hand, a bistable deformable capsule 3 advantageously passes, relatively abruptly, under the effect of a support 13, from a free form 14 to a compressed form 15. This passage from a free form 14 to a compressed form 15 is accompanied by a shock, advantageously felt by a finger performing the support 13. Thus the capsule 3 contributes to produce a clear tactile sensation, informing by feedback effort,

0055According to the material constituting the capsule 3, typically made of metal, for example aluminum, but also of plastic material (then metallized to ensure the function of electrical conductor), the passage from a free form 14 to a compressed form 15 'still advantageously accompanies an audible' click '. Thus the capsule 3 contributes to producing a sound return, informing the actuation of the electric switch 1 and thus its effective state, here closed.

0056It may also be noted that during the reverse passage, from the compressed form 15 to the free form 14, the tactile feedback and the sound return are still present, and inform the non-actuation of the electric contactor 1 and thus of its effective state, here open.

0057Another advantage of a capsule 3 having a bistable deformation is its elasticity. Such a capsule 3 spontaneously returns to its free form 14 when the support 13 ceases. In doing so it accompanies and helps the membrane 4 in its movement back to its rest position.

0058According to an advantageous characteristic of the shape of the capsule 3, it has been seen that the height 8 measured between the apex 6 of the capsule 3 and at the right of a terminal 2, is advantageously greater than a height 9 of a terminal 2 relative to the elastically deformable membrane 4, in order to keep the terminals 2 away from the capsule 3 in the open position. This condition is advantageously achieved in the open position, the capsule 3 being in its free form 14.

0059According to an advantageous characteristic, when the capsule 3 passes into its compressed form 15, this condition is reversed, the height 8 'measured between the top 6 of the capsule 3 and at the right of a terminal 2, becoming advantageously less than the height 9 of a terminal 2 relative to the elastically deformable membrane 4, in this case to promote contact between the terminals 2 of the capsule 3 in the closed position. Also the deformation of the capsule 3 between two distinct and remote forms favors the change of position of the electric switch 1 between an open position and a closed position and vice versa. In other words the bistable deformation of the capsule 3 advantageously allows a retraction of the protuberance of the top 6 of the capsule 3 and the inversion of the protrusion condition.

0060It is notable, however, that the change of position of the electric switch 1 between the open 11 and closed 12 positions does not necessarily coincide with the change in shape of the capsule 3. As illustrated in FIG. <figref idref="f0002">figure 4</figref> the deformability of the membrane 4 may be sufficient for the terminals 2 to come into contact with the capsule 3 again in its free form 14. However, even in this case the support 13 then causes a change of shape of the capsule 3. This shape change follows in this case the change of position of the electric switch 1. On the contrary, as illustrated in the <figref idref="f0003">figure 5</figref>, the change of shape of the capsule 3 to a compressed form 15 may be necessary for the establishment of a contact between the terminals 2 and the capsule 3. In this case, the change of shape of the capsule 3 precedes the change of position of the electric switch 1.

0061According to another advantageous characteristic, more particularly illustrated in the <figref idref="f0004">Figures 6 and 7</figref>, the capsule 3 comprises a stud 16 at its top 6. Such stud 16 reinforces the protuberance of said vertex 6 while limiting the extent in the plane of the card 10. Thus, such a stud 16 advantageously allows to achieve more easily the protuberance condition and its inversion. In the free form 14 said pin 16 facilitates the realization of the condition: the height 8, more particularly illustrated in the<figref idref="f0004">figure 6</figref>, is greater than the height 9. The pin 16 is located in the center of the capsule 3 and thus in the area where the support 13 is made. This favors the passage in compressed form 15. Thus, the pin 16 promotes reversal. of the protuberance condition. In the compressed form 15, the condition is reversed: the height 8 ', more particularly illustrated in FIG.<figref idref="f0004">figure 7</figref>, becomes lower than height 9.

0062Said stud 16, by accentuating the difference between the free form 14 and the compressed form 15, while ensuring the shape change in a smaller space in the plane of the card 10, advantageously allows the two terminals 2 to be brought closer together in the same plan and therefore one of the other. This contributes to making it possible to produce an electric contactor 1 of dimensions, in this same plane, very small, while maintaining a good separation between the two open positions 11 and 12 closed.

0063The present invention also relates to a method of manufacturing such an electrical conductor 1 for thin plastic card 10. This method comprises a first step of machining a cavity 5 in the thickness of a thin plastic card 10. The card thin plastic 10 is assumed to have previously been made in the usual manner by rolling different layers. Then, the cavity 5 is made by machining a cut, advantageously non-emerging, in the thickness of said thin plastic card 10. Such a procedure is particularly advantageous, in that it makes it possible to avoid resorting to an integrated insert during rolling. In doing so, it avoids the components of the electric contactor 1 to undergo the pressure and temperature constraints associated with the rolling operation.

0064Then, a conductive element 3 / a capsule 3 is put in place in the cavity 5. As discussed above, the conductive element 3 may, during this step, be glued or otherwise fixed by any means in the cavity 5. However, a conformation and dimensions of the conductive element 3 adapted to those of the cavity 5 may allow to leave the conductive element 3 free in the cavity 5 and thus avoid a fixing step.

0065In parallel the terminals 2 are made associated with an elastically deformable membrane 4. For this, an etching technique, those known in the field of manufacturing printed circuits, is advantageously used. Such etching may be positive: deposition of material corresponding to the terminals 2 or negative: removal of material does not correspond to the terminals 2. A plastic membrane 4 is adapted to receive such an etching. PET preferentially used supports such an etching.

0066The cavity 5, equipped with the conductive element 3 can then be closed by placing the elastically deformable membrane 4, the terminals 2 facing the cavity 5. Said membrane 4 is typically held in place by gluing, on all or part of the upper surface of the thin plastic card 10. As illustrated in the figures, a counterbore may be provided so that no difference in thickness appears on the outer surface of the thin plastic card 10.