Contactless IC-card with an antenna made from a conductive polymer

p0001The present invention relates to an IC card.

p0002There are known integrated circuit cards called contactless card comprising a plastic card body, an integrated circuit fixed in a cavity of the card body, and an antenna extending over a face of the card body and connected to the integrated circuit . It is known to make the antenna by depositing a conductive polymer, in particular by screen printing.

p0003In all known contactless cards is provided to cover the integrated circuit and the antenna by a covering sheet which ensures maintenance of the integrated circuit in the cavity of the card body and a protection of the antenna and its connection with the pads of the integrated circuit.

p0004The introduction of the cover sheet is generally carried out by hot rolling. To reduce the cost of manufacture is generally provided to simultaneously perform multiple cards by implanting more integrated circuits on a single plastic sheet and then simultaneously performing the antennas associated with each integrated circuit. A cover sheet is then placed on the plate thus obtained and the whole is placed in a lamination press where the board and the cover sheet associated are heated and pressurized. The assembly obtained is then cut to separate the different cards.

p0005Despite the economy achieved by the simultaneous production of multiple cards, the introduction of a cover sheet remains very expensive due to the significant investment represents a laminating press and the relatively long duration (about 20 minutes) of the rolling operation of the cover sheet to the card body. In addition, the cover sheet rolling process represents a bottleneck with respect to the other steps of manufacture of a card and is an obstacle to high production rates.

p0006Furthermore competition ever increasing implies an ongoing search for cost reduction while the requirements for reliable operation of the cards is increasing.

p0007card manufacturers are continually faced with looking for two conflicting goals of lowering the manufacturing cost and the maintenance of a sufficient quality of the products obtained.

p0008According to the invention there is provided an IC card comprising a card body, an integrated circuit fixed in a cavity of the card body, a conductive polymer antenna extending on a face of the card body and connected to the integrated circuit, and a resin layer covering the integrated circuit and at least a portion of the next adjacent card body to the integrated circuit.

p0009Thus, the deposition of the protective resin may be carried out continuously, for example by sérigra phy, this operation is carried out at low cost while ensuring the protection of at least the area of the map that is most likely to be causing a shutdown of the card. Thus a satisfactory compromise between looking for a lower cost and maintaining good reliability.

p0010Note that in the case of an antenna with small dimensions, or in the case of a stacked antenna to the integrated circuit, conducting a resin layer on the integrated circuit and the part of the card body immediately adjacent, possible to cover all the elements forming the sensitive part of the IC card so that one obtains a cost reduction without any loss of reliability over existing systems.

p0011According to an advantageous version of the invention the integrated circuit has a thickness less than 120 microns and is disposed substantially in the vicinity of a neutral axis of the card in vertical alignment with the resin layer. And the very small thickness of the integrated circuit gives it great flexibility minimizing stress upon bending of the card, and its arrangement in the vicinity of the neutral axis of the card still reduces stress in particular in the vicinity of edge of the integrated circuit where there is a greater risk of breaking the antenna, so that this advantageous embodiment of the invention further increases the reliability without increasing the cost of the IC card.

p0012Other characteristics and advantages of the invention will appear on reading the following description of a particular embodiment not limiting the invention in connection with the attached single figure which is a sectional view map without contact of the invention.

p0013Referring to the figure, the contactless card according to the invention comprises in a manner known per se a 1 card body of plastic, an integrated circuit 2 fixed in a cavity of the card body, for example by pressing hot the integrated circuit in the card body, and an antenna 3 extending on a face of the card body and connected to the integrated circuit. In known manner the integrated circuit flush with one of the faces of the card body and the antenna 3 is for example formed as a series of turns of conductive polymer deposited by silkscreen printing on the face of the card body 1 flush by the integrated circuit 2.

p0014According to the invention the contactless card comprises a resin layer 4 covers the integrated circuit 2 and at least a portion of the card body immediately adjacent the integrated circuit.

p0015According to an advantageous aspect of the invention, the integrated circuit 2 has a small thickness, preferably less than about 120 microns and is disposed substantially in the vicinity of the neutral axis of the card in vertical alignment with the resin layer 4, symbolized by a dashed late in Figure 1. This minimizes the stresses to which the integrated circuit, especially the connections of the integrated circuit with the antenna, are subject in the introduction of the contactless card according to the invention on an object.

p0016Naturally, the invention is not limited to the embodiment described and can be devised alternative embodiments within the scope of the invention as defined by the claims.

p0017In particular, although the invention has been illustrated in connection with a card in which the resin layer 4 does not totally covers the antenna 3, it can provide a resin layer 4 completely covering the entire integrated circuit - antenna, or even all of the corresponding face of the card body.

p0018Although the invention has been illustrated with respect to a contactless card comprising an inductive antenna, the antenna may also be a capacitive coupling element or coupling element for a contactless transmission signals.