BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood in the text below together with the following drawings:
FIG. 1 shows a first embodiment of a card according the invention
FIG. 2 shows a first state of the manufacture of the card of the FIG. 1
FIG. 3 shows a second state of the manufacture of the card of the FIG. 1
FIG. 4 shows a third state of the manufacture of the card of the FIG. 1
FIG. 5 shows a second embodiment of a card according the invention
FIG. 6 shows a detail of the embodiment of FIG. 2
FIG. 7 shows a third embodiment of a card according the invention
FIG. 8 shows a fourth embodiment of a card according the invention and
FIG. 9 shows a fifth embodiment of a card according the invention
DETAILED DESCRIPTION OF THE INVENTION
To start with, one manufactures an ISO card with Printed or Wire Embedded antenna by using a standard process.
In the antenna design of FIG. 1, one just separates one of the tracks from the others. The antenna can be manufacture by any technique known in the art as wire embedding, printing, etching, etc. In the embodiment illustrated in FIG. 1 to 4, the antenna is made with a wire embedded wire 6, for example of copper with an insulation coating 7.
FIG. 2 shows a detail of the card of the FIG. 1 before the manufacture of the switch.
Then, as shown in FIG. 3, one mills a cavity 8 in the card by using a standard milling process as for chip embedding for contact cards or dual interface cards. This milling operation (by the manufacture of the secondary cavity 9) cuts the track (e.g. wire) of the antenna which leads to an open circuit.
Of course, any milling process can be used. Important is that the wire forming the antenna is cut and that a part of the two extremities 5′ and 5″ of the wire are stripped in the cavity. One can manufacture a simple cavity (i.e. without secondary cavity 9) deep enough to cut the wire. In such a case, the conductive interfaces between the core of the wires and the elasto-resistive correspond to the parts of the side wall of the cavity occupied by the wires. Preferably, such a cavity would be conical, to present larger interface surfaces of the wires.
Then, as shown in FIG. 4, one places into this milled area a material 10 which has the characteristics of being conductive under pressure. Basically when one presses (12) on it, it closes the open circuit and then the card is readable since the antenna is fully functional.
Preferably, the cavity 8 is not totally filled with the elasto-resistive material 10 to avoid unwanted action of the switch.
An insulation cover layer (not represented) could be put over the upper surface of the material 10, in order to avoid any resistive interference of the antenna with the finger of the user when pressing on the switch.
FIG. 5 shows a similar embodiment to FIG. 1, in which the antenna design is slightly different. One makes a narrow bend resulting in the two close parallel wires shown in a more detailed manner in FIG. 6. The wire is stripped during the milling operation of the main cavity 8, and the tip of the bend is cut during the milling of the secondary cavity 9, resulting in the two stripped wire extremities 5′ and 5″ in the cavity 8.
Once again, the cavities 8 and 9 are (partially) filled with an ER (or QTC) material. FIGS. 7-9 show different embodiments of the invention, where the antenna is not cut during the milling, but presents contact extremities 15′ and 15″ from the beginning. The common idea of these embodiments is to connect these extremities with an elasto-resistive switch.
FIG. 7 shows a contact and contactless card according the invention. The main design and manufacture process is identical to the one known in the art, for example from EP 0 671 705. One significant difference is that the two columns between the contact pads 14 of the chip module 13 and the contact extremities 15′ and 15″ of the antenna 4 are filled with an elasto-resistive material 10. Pressing on the chip module 13 makes the material 10 conductive and allows the card to be read. The module 13 as to be fixed in a movable manner in the cavity. This could be achieved for example by using a elastic filler 16 as fixing mean, allowing the pressure of a finger on the chip module to be transmitted (at least partially) to elasto-resistive material 10.
FIG. 8 illustrates the manufacture of an antenna bridge (as known in the art) including a switch according the invention. In the prior art, in particular for printed antenna, one has to create a bridge over the antenna loops in order to close the circuit formed by the antenna 4 and the chip module 13. In this embodiment of the present invention, an insulating layer 17 is first applied to cover and to isolate the antenna loops 4. Then, an elasto-resistive material 10 is applied over the bridge isolation layer 17, in order to connect the two contact extremities 15′ and 15″ of the antenna.
FIG. 9 shows another embodiment of the invention. The elasto-resistive material can be from the beginning integrated in a recess 20 formed in the core support layer 18 of the card inlay. The elasto-resistive material 10 is placed in the core layer from the beginning of the manufacture process to avoid the milling step (with the antenna in the card core). The antenna is then manufactured as an open circuit with two free extremities 15′ and 15″ placed on the material 10. The material fills a through hole of the core layer and the two antenna parts are placed on each side of the core layer. It is of course possible to have both antenna parts on the same side of the layer.
LIST OF NUMERAL REFERENCES
1 card
2 switch
3 chip module
4 antenna
5 antenna wire before milling
5′, 5″ extremities of antenna wire
6 core of antenna wire
7 isolation of antenna wire
8 main milled cavity
9 secondary milled cavity
10 elasto-resistive material
11 unfilled part of the cavity
12 pressure action on the switch (with finger)
13 chip module (contact and contactless type)
14 contact pads of the module
15′,15″ contact extremities of the antenna
16 fixing elastic material
17 bridge isolation layer
18 core support layer of a card inlay
20 cavity in support layer
Patent Application
20070290051
