DEVICE

DESCRIPTION This invention relates to secure documents comprising a radiofrequency identification device, and particularly secure documents comprising a radiofrequency identification device with reinforced protection of the said radiofrequency identification device. Contactless radiofrequency identification (RFID) devices are increasingly used to make documents secure, particularly by incorporating these RFID devices inside the document itself. A contactless RFID device is a device made up of an antenna and a chip connected to the terminals of the antenna. The chip is generally not powered and receives power through electromagnetic coupling between the antenna of the reader and the antenna of the RFID device; information is exchanged between the RFID device and the reader, particularly information stored in the chip, for example relating to the identification of the holder of the document or other types of information relating to the document on which the device is placed.

Thus, secure documents such as passports for example may incorporate RFID devices for identifying the holder of the document. In the case of a passport, the memory of the chip contains information such as the identity of the holder of the passport, their country of origin, their nationality, the visas of the different countries visited, entry dates, movement restrictions, biometric data etc.

The RFID device is generally manufactured independently from the document and is then incorporated by gluing between the cover and the bottom of the first page, for example, of the passport. The RFID device comprising the antenna and the chip connected to each other is then integrated into a substrate made of paper, plastic or other material (commonly called 'inlay'). Such documents are flexible documents and are subjected to twisting and bending stresses that can be withstood by the RFID device inserted in them without damage, providing the said stresses merely curve the document and the substrate. However, if the stresses are too great, the document is not sufficiently flexible and the curve can turn into a break or fold that can damage the RFID device. That is even more true when the document takes the form of a book like a passport, and thus has a more rigid binding system that can result in much easier folding or breaking if the bend is perpendicular to the said binding .

Thus, one of the aims of the invention is to provide a secure document comprising a radlofrequency identification device allowing improved protection of the said radlofrequency identification device if it is bent. Th is i nvention th us rel ates to a secu re d ocu ment co m prisi ng a su bstrate i nteg rati ng a rad lofreq uency identification device, the said substrate comprising at least one slot.

According to one aspect of the invention, the said at least one slot is made by incising the substrate close to the radlofrequency identification device.

According to another aspect of the invention, the length of the said at least one slot is greater than or equal to the size of the radlofrequency identification device.

According to another aspect of the invention, the length of the said at least one slot is smaller than the size of the radlofrequency identification device.

According to another aspect of the invention, the said at least one stress relief slot has the shape of a curve around the radlofrequency identification device. According to another aspect of the invention, the secure document takes the form of a booklet with a hinge.

According to another aspect of the invention, the stress relief means are located between the hinge and the radiofrequency identification device.

According to another aspect of the invention, the secure document is an electronic passport. Other characteristics and benefits of the invention will become clearer in the description below, provided as an illustrative and non-limitative example, and the attached drawings, where:

- figures la and lb are schematic representations of the behaviour of the secure document depending on the bending stresses applied to it,

- figures 2a and 2b are schematic representations of the top view of the behaviour of the bend of a secure document with and without the subject of the invention,

- figure 3 is a schematic representation of a sectional view of a secure document according to the invention .

Identical elements in the different drawings have identical reference numbers. Figures la and l b show the behaviour of a secure document 1 that takes the form of a booklet, depending on the bending stresses. The secure document 1 is supported by two pins 3 and pressure is applied by pin 4.

In figure la, the pressure applied by the pin 4 is less than the deformation tolerance of the secure document 1 and the document merely bends.

In figure lb, the pressure applied by the pin 4 is greater than the deformation tolerance of the secure document 1 and the document breaks or folds 5. A fold 5 may also be formed by the repeated application of pressure below the deformation tolerance of the secure document 1. Figure 2a shows the effect of such a fold 5 if the secure document 1 takes the form of a booklet, with a hinge 9.

The fact that the secure document 1 has a hinge 9 reduces its tolerance to deformation in the case of bending stresses perpendicular to the said hinge 9, resulting more easily in a fold 5.

If the secure document 1 has a contactless radiofrequency identification device (RFID device) 11 ; 13, integrated into a substrate 7 well known to the person of the art, the fold 5 could go through the antenna 11 or the electronic chip 13 and damage them or even cut the antenna 11 and put the RFID device 11 ; 13 out of order.

An example of a secure document 1 may be an electronic passport that uses the technology of RFID devices integrated into the cover to store data on the processor of the said electronic passport.

Figure 2b shows a secure document 1 similar to that presented in figure 2a, that is in the form of a booklet with a hinge 9 and an RFID device 11 ; 13 integrated into a substrate 7.

The secure document 1 here has at least one slot 15 on the substrate 7 that makes it possible to relieve the stresses applied by the fold 5 and thus divert the fold 5 to protect the RFID device.

The slot 15 is preferentially made by incising the substrate 7 near the RFID device 11 ; 13. Figure 3 illustrates this case, showing a sectional view of a schematic representation of a secure document 1 such as an electronic passport, with a substrate 7 integrating an RFID device 11 ; 13 and a slot 15 made in the said substrate 7, and a cover 17.

The slot 15 may be of several types; it may go through the substrate 7 entirely or only represent a reduction in the thickness of the said substrate 7 that is sufficient to make up an area of weakness in which the fold 5 can be guided . The slot 15 may also be continuous over its entire length or only be made up of a series of small dotted incisions that make up an area of weakness in which the fold 5 can be guided . In order to protect the RFID device 11; 13, the slot 15 may particularly be placed between the hinge 9 and the RFID device 11; 13 since the said hinge 9 is the portion of the secure document 1 with the least tolerance to deformation and is thus the most liable to give rise to a fold 5. In order to divert the fold 5 more effectively, the sl ot 15 may preferentially have a curved shape around the RFID device 11; 13 as shown in figure 2b and in order to protect the said RFID device 11; 13 most effectively, the length of the said stress relief slot 15 may preferentially be greater than or equal to the size of the RFID device 11; 13. The size of the RFID device 11; 13 means both its length or its width.

Of course, the length of the slot 15 may also be smaller than the size of the RFID device 11; 13, for example when the RFID device is located close to the edges of the secure document 1 perpendicular to the hinge 9 and where it is necessary to divert a fold 5 only over a small length in order to protect the said RFID device 11; 13.

The slot 15 may also have shapes different from that of the curve shown in figure 2b. For example, the said slot 15 may also be straight, parallel or oblique in relation to the RFID device 11; 13 or have a break angle over its length demarcating two portions each directed on one side of the said RFID device 11; 13.

Further, any one secure document 1 may contain one or more slots 15 arranged parallel to each other.

Thus, it can be seen that the secure document with at least one slot makes it possible to divert a fold around an RFID device to protect the RFID device, where the said fold would otherwise have damaged the said RFID device and put it out of order.