Security document with a transparent window

Abstract

Security document comprising a body composed of at least two transparent plastic substrates (12a, 12b) and delimited by edges (16) forming a substantially rectangular surface comprising four corners, at least one of the substrates (12a, 12b) receiving a printing layer (20) opaque in the visible range and applied to the edges (16) of the document (10), the printing layer (20) delimiting a peripheral portion (24) at least partially devoid of printing forming a set of lines bordering a secure area (27) containing security information, the peripheral portion (24) having a smaller unprinted dimension of between 100µm and 500µm, such that the plastic substrates (12) are in direct contact and assembled in the peripheral portion (24). Figure 7 [Fig. 7]

Description

Title of the invention: Security document with a transparent window

[0001] The invention relates to the field of security documents such as contact or contactless smart cards, or even chipless cards, made of a plastic material, and which may have different formats specified in standards (to be specified). By way of example, these formats are called ID1 (bank card format), ID2, which is twice the size of ID1 (French national identity card format), and ID3 (passport format).

[0002] The invention relates particularly to security documents comprising a printing layer possibly forming one or more transparent windows.

[0003] Prior art is known for security documents incorporating windows by cutting a cavity in a printed card body and then inserting a transparent insert into the cavity. Patent EP3389963 describes such a security document, and in particular the manufacturing process used to produce it on mass production lines. Inserting a transparent insert or disc remains a costly and complex process due to the difficulty of automatically inserting said insert.

[0004] It is also known in the prior art (US 10909334) to create a window by filling a cavity, previously cut in an opaque central layer, with a plastic material obtained by deforming two transparent substrates positioned below and above the central layer. The deformation of the substrates is caused by the application of high pressure and temperature during lamination. When the glass transition temperature is reached, the plastic material becomes viscous and fills the cavity formed in the opaque substrate. Upon cooling, the plastic material returns to a solid state and thus forms the transparent window of the security document.

[0005] However, this solution has the disadvantage of leaving, on the surface of the document, a mark corresponding to the area of ​​the transparent window, in particular a mark of the area of ​​flow of the material.

[0006] It is also known in the prior art to create transparent windows by producing an area without printing. For this purpose, a transparent substrate is applied, onto which a printing layer is deposited. The printing layer is applied to the entire surface of the substrate, except for a delimited area to form the window. This substrate is then bonded with one or more other layers. transparent, allows to form a security document opaque in the area where the printing layer is deposited and transparent in the area delimiting the window.

[0007] However, this solution has a major drawback when the plastic substrate is made of polycarbonate. Indeed, polycarbonate has very weak adhesion properties with other materials. Thus, after laminating a polycarbonate substrate with another polycarbonate substrate covered with a printing layer, the adhesion properties at the interface between the printed layer and the polycarbonate substrate remain weak.

[0008] To date, there is no ink compatible with polycarbonate that guarantees perfect cohesion between the polycarbonate layers and the ink of the printing layer. It is therefore necessary to limit the ink coverage to a maximum of 30-40% of the substrate surface to avoid the risk of delamination due to a lack of cohesion between the layers, or to seal the card 30 with 3mm transparent edges 32 to secure and protect the elements of identity documents, as illustrated in [Fig. 1]. However, this latter option restricts the possibilities for designs, compatibility with security features such as laser engraving, other printing methods, or hologram insertion, and does not meet customer requirements.

[0009] There are therefore one or more drawbacks to using prior art solutions when the security document must be viewed as opaque except for the window area. The ink printing then implies a 100% coverage rate, leading to a risk of delamination at the interface between the ink and the polycarbonate substrate. This, in turn, creates a significant risk of fraud and compromises the security document's durability. It is then possible to attack the document from its edges and recover security features.

[0010] The invention proposes to remedy this drawback.

[0011] To this end, the invention proposes a security document comprising a body composed of at least two transparent plastic substrates and delimited by edges forming a substantially rectangular surface comprising four corners, at least one of the substrates receiving an opaque printing layer in the visible range and applied up to the edges of the document, the printing layer delimiting a peripheral part at least partially devoid of printing forming a set of lines bordering a secure area containing security information, the peripheral part having a smaller dimension devoid of printing between 100pm and 500pm, so that the plastic substrates are in direct contact and assembled in the peripheral part.

[0012] Thanks to these arrangements, the documents have a printed layer over their entire surface except for a peripheral part, such as a strip A very thin, unprinted strip, also called a groove, embedded within the printed design, allows contact between the two plastic substrates. This ensures a more robust bond between the different substrates that make up the document and prevents separation of the document's layers. Furthermore, this very thin strip allows for a greater variety of designs and compatibility with security features such as laser engraving, other printing methods, or hologram insertion, thus meeting customer requirements.

[0013] According to other characteristics:

[0014] the peripheral part is completely devoid of printing; the peripheral part is partially devoid of printing by the formation of unprinted striations separated by printed edges; the striations and the edges have roughly the same smallest dimension; the secure area bordered by the peripheral part represents 90% of the document's surface area; the secure area bordered by the peripheral part represents less than a quarter of the surface of the document and includes a security element such as an engraved portrait, a printed portrait, a diffractive element; the thickness of the printing layer being between 5pm and 50pm; the peripheral area without printing forms a continuous pattern forming a loop on the surface of the document or a continuous pattern between two edges of the document; the peripheral area without printing forms a discontinuous pattern; the discontinuous pattern is formed by the association of four peripheral zones, each formed in the vicinity of the four corners of the document and extending substantially parallel to the edges; the printing layer delimits an area without printing so as to create a transparent window in the security document; The plastic substrates are polycarbonate substrates.

[0015] [Fig-1] [Fig.1] represents a safety document according to the prior art,

[0016] [Fig.2] Fig.2 represents a front view of a safety document according to the invention,

[0017] [Fig.3] Figure [Fig.3] represents a cross-sectional view of a safety document according to the invention,

[0018] [Fig.4] Figure [Fig.4] shows a detailed view of a safety document according to the invention following an attempted delamination,

[0019] [Fig.5] Figure [Fig.5] represents a curve illustrating the force applied during the delamination of a document according to the invention, up to the point of breakage,

[0020] [Fig. 6a] and [Fig. 6b] Figures 6a and 6b represent two examples of patterns from a safety document produced according to the invention.

[0021] [Fig.7] Figure [Fig.7] represents a document according to a variant of the invention,

[0022] [Fig.8] The [Fig.8] represents a document according to another variant of the invention.

[0023] The invention relates to identity documents 10 and more particularly to ID-1 format documents corresponding to the format of a smart card as specified in ISO7816-1, as illustrated in [Fig. 2]. The invention also applies to other formats such as that of a plastic page integrated into a passport.

[0024] These documents 10 are used to receive data relating to the identity of individuals and are therefore susceptible to being fragmented in order to recover their security features or to create fraudulent security documents. This involves, in particular, separating the layers that make up the document in order to recover security features for insertion into counterfeit documents. It is therefore important that the reproduction or falsification of this type of document remains very difficult, if not impossible.

[0025] The documents are generally made up of several (at least two) plastic substrates assembled together after a lamination step in which the substrates are pressed between two lamination plates at high temperature, for example 200°C. [Fig. 3] illustrates a safety document 10 made up of two plastic substrates 12a, 12b, preferably polycarbonate.

[0026] The two substrates 12a, 12b are assembled to form document 10, which has a first outer face 14a and a second outer face 14b opposite the first outer face 14a. In the following description, the first and second faces 14a, 14b will be referred to respectively as the upper face 14a and the lower face 14b of document 10, according to the conventional observation of these documents 10. Document 10 is further defined by four edges 16 having a thickness equal to that of document 10 and extending between the upper face 14a and the lower face 14b. The edges 16 have a very thin thickness, less than 1 mm, and together define the contour 18 of document 10. Document 10, and consequently the two substrates 12a, 12b, have the same contour 18.The contour is defined during cutting by the following manufacturing process: the plastic substrates 12a, 12b are first assembled together to form an intermediate product of several substrates 12a, 12b, this intermediate product is then cut to the desired format to obtain the final document 10 of contour 18.

[0027] As stated above, document 10 has a format specific to identity documents, namely a bank card or passport format. Document 10, and consequently the two substrates before lamination, each therefore have a contour 18 delimiting a rectangular surface and formed by four sides connected to each other by four corners respectively.

[0028] Generally, at least one of the two substrates 12a receives a printing layer 20, for example, an ink or a varnish, which forms a decorative pattern or personalization data relating to the cardholder. This printing layer 20 is located at the interface of the two plastic substrates 12a, 12b, after lamination of the security document, as illustrated in Figures 2 and 3. This printing layer 20 is deposited on the substrate 12a by printing techniques known to those skilled in the art, namely inkjet printing, offset printing, or screen printing. The color of the printing layer 20 is chosen according to the pre-selected pattern, and the density of pigments coloring the ink is determined in advance according to the desired opacity and hue.

[0029] The printing layer 20 is applied over an entire surface of the substrate 12a, that is to say up to the contour (or edges) of said substrate 12a, with the exception of an area intended to form a transparent window 22, in association with the other substrates 12b of the document 10, and with the exception of a peripheral part 24 which will be described in more detail in the rest of the description.

[0030] The printing layer 20 has a very thin thickness of 5 to 50 µm. Despite its thinness, the printing layer 20 provides sufficient opacity so that a user cannot see through it under ambient lighting. The printing layer 20, deposited using techniques mastered by those skilled in the art, allows for the creation of varied shapes and graphics with great freedom at a lower cost. This simple and inexpensive window 22 fabrication technique offers a considerable advantage compared to the cutting and insertion of a transparent insert technique described earlier.

[0031] The unprinted area forming the transparent window 22 allows the user to observe different information. This could be, for example, a pattern engraved in the thickness of the transparent window 22, such as a secondary portrait, or a hologram, positioned between two substrates and whose color varies according to the lighting to which the document 10 is subjected.

[0032] However, depending on the nature of the ink in the printing layer 20, there are adhesion incompatibilities with plastic substrates 12a, 12b, and particularly with polycarbonate substrates 12a, 12b. To date, no ink is known that allows strong and durable adhesion to a polycarbonate substrate. This creates a real security risk for the documents 10, which can then be separated into several elements and subsequently reused in fraudulent documents.

[0033] The invention aims to remedy this problem by providing a peripheral portion 24 that is partially or totally unprinted. To this end, the peripheral portion 24, at least partially unprinted, forms a set of lines bordering a secure area containing security information. Thus, the plastic substrates 12 are in direct contact and assembled within the peripheral portion 24 that borders said secure area.

[0034] The peripheral part has a smaller dimension without printing, between 100 and 500 µm. This smaller dimension is, for example, the width of a narrow strip.

[0035] In this peripheral part 24, the two substrates are in contact and bonded by chemical and physical adhesion after the lamination step.

[0036] Indeed, during lamination, the plastic substrates 12a, 12b undergo a temperature increase above the glass transition temperature. Their state is then modified such that the surface material of one substrate 12a softens and exhibits fusion and adhesion properties with the other surface of the second substrate 12b, which has undergone the same transformations. In this case, when two polycarbonate substrates 12a, 12b are laminated together, the surfaces at the interface of the two substrates 12a, 12b undergo a transformation sufficient to create strong material cohesion between the two substrates 12a, 12b. This cohesion is present over the entire peripheral area 24, making it very difficult to separate the two substrates 12a, 12b without damaging them.

[0037] This effect is demonstrated by the diagram in [Fig. 4] and by the curve in [Fig. 5] illustrating the mechanical behavior of the elements constituting the security document in [Fig. 2]. When a malicious user attempts to separate the substrates 12a, 12b from the document 10, the adhesion force of the printing layer 20 is less than that which would cause the removed substrate to break. It is therefore possible to begin separating the first substrate 12a from the second substrate 12b covered by the printing layer 20. This is illustrated by the first part of the curve in [Fig. 5], representing a substantially constant and low pull-out force. However, in the peripheral part 24, which is unprinted, the force required to separate the substrates 12a, 12b increases sharply, as illustrated in [Fig. 5] by the abrupt increase in the curve, forming a peak representing the force required to separate the two substrates at the peripheral part 24.This separation force, which is an elastic tensile force applied to substrate 12a, increases until it reaches the breaking point of the polycarbonate substrate 12a.

[0038] It therefore becomes impossible to separate the two polycarbonate substrates 12a, 12b intact, because this operation results in the irreversible tearing of at least one of the two substrates 12a, 12b in the peripheral part 24 lacking printing. The two substrates 12a, 12b are then rendered unusable for falsifying or manufacturing a fraudulent document.

[0039] In order to prevent the separation (or peeling) of the substrates constituting a document, it is important that this peripheral part 24 extends between one or more edges 16 of the document and the secure area to be protected, close to the secure area to be protected.

[0040] According to a first embodiment illustrated in Figures 2, 6a and 6b, the peripheral part 24 is formed of at least four peripheral zones 24a, 24b, 24c, 24d, each formed in the vicinity of the four corners of the document 10 and extending substantially parallel to the sides of the document 10. The four peripheral zones 24a, 24b, 24c, 24d are arranged near the four corners of the card to ensure strong adhesion between the plastic layers at the corners, which are likely to be a delamination initiation zone of the different substrates 12a, 12b constituting the document 10. The peripheral part is made very thin, between 100 µm and 500 µm, and is barely perceptible to the naked eye for an observer and, moreover, leaves a majority of the surface of the substrate 12a, 12b available for the printing layer 20.

[0041] Each of the four peripheral zones 24a, 24b, 24c, 24d is positioned near a corner, at a distance of less than 5% of the length of the side forming the corner. This has the advantage of ensuring that the substrates 12a, 12b cannot be separated beyond this distance. Thus, the central part of document 10, forming the secure zone, is preserved due to the seal between the plastic substrates 12a, 12b at the level of the peripheral part 24, particularly at the level of the peripheral zones 24a, 24b, 24c, 24d. It is not possible for a fraudster to access the security features positioned in this central part forming the secure zone from the edge of document 10.

[0042] In Figures 2 and 3, the peripheral portion 24 forms a continuous pattern represented by the four interconnected peripheral zones 24a, 24b, 24c, 24d. These four peripheral zones are positioned near the four corners of the board to ensure strong adhesion between the plastic substrates at the corners, which are susceptible to delamination initiation zones in the different layers of the board.

[0043] The peripheral part 24 without printing 20 can have different shapes which will be described below.

[0044] According to a first embodiment, illustrated by Figures 2 to 6 and 8, the peripheral part 24 is completely devoid of printing. Adhesion between the plastic substrates 12a, 12b is thus achieved over the entire length and width of the peripheral part 24. This can be a continuous line parallel to the edges of the document as seen in [Fig.2].

[0045] According to a second embodiment, illustrated in [Fig. 7], the peripheral portion 24 is partially unprinted by the formation of unprinted striations 26 separated by printed edges 28. The smallest unprinted dimension is then formed by the width of the striations 26 and is between 100 µm and 500 µm. Adhesion between the two substrates is thus achieved over the combined surfaces of the striations 26. Advantageously, the striations 26 and the edges 28 have substantially the same smallest dimension, so that adhesion between the substrates occurs over at least half the surface area of ​​the peripheral portion. [Fig. 7] illustrates a peripheral portion 24 partially unprinted extending to the edges 16 of the document 10. This embodiment has the advantage of being aesthetically pleasing and providing continuity with the printing in the central area of ​​the card.Furthermore, this method is relatively easy to implement because printing is a process that allows for the creation of numerous designs without great technical difficulty.

[0046] According to an alternative embodiment shown in Figures 2, 6a, 6b, the secure area bordered by the peripheral portion covers 90% of the document's surface. In these alternative embodiments, the peripheral portion 24 extends near the edges 16 of the document 10, or even to the edges 16 of the document 10. As explained previously, the central portion of the document 10, forming the secure area, is protected by the seal between the plastic substrates 12a, 12b at the level of the peripheral portion 24. Therefore, it is not possible for a fraudster to access the security features located in this central portion.

[0047] In the embodiment illustrated in [Fig. 7], there are two secure areas 27a, 27b, each bordered by a peripheral portion. The first secure area 27a covers 90% of the document surface, and the second secure area 27b represents less than a quarter of the document surface and includes a security feature 29. In [Fig. 7], the security feature 29 is a printed portrait, but it could be an engraved portrait or a diffractive element.

[0048] According to another variant, the peripheral part 24 forms a continuous pattern such as a loop forming a closed loop visible on [Fig.2] or a continuous pattern between two edges 16 of document 10, as illustrated in [Fig.8].

[0049] Figures 6a and 6b represent two examples of graphics of peripheral parts 24 without printing of a document 10 produced according to the invention.

[0050] Unlike Figures 2 and 3, the embodiment examples in Figures 6a to 6b illustrate a discontinuous peripheral part 24 represented by the combination of four peripheral areas 24a, 24b, 24c, 24d separated from each other by printing areas and arranged near the four corners of the card to ensure a strong adhesion between the plastic layers at the corners which are susceptible to a delamination initiation zone of the different layers of the card. Each of the four peripheral zones 24a, 24b, 24c, 24d is positioned near a corner, at an equal distance of 5% of the length of the side forming the corner.

[0051] In Figure 6b, the four peripheral areas 24a, 24b, 24c, 24d form a figurative ornamental motif, for example the outline of a country.

[0052] In [Fig.6a], the four peripheral zones 24a, 24b, 24c, 24d form an abstract ornamental pattern; the four peripheral zones are grouped in pairs to form a partially discontinuous peripheral part 24.

[0053] The invention also relates to a method for manufacturing a security document. This method comprises the steps of providing at least two transparent substrates, such as polycarbonate substrates. Then, a printing step is carried out on one face of one of the two substrates by applying a printing layer delimiting a transparent peripheral area 24 and optionally a transparent window 22. The two substrates are then joined by lamination, so that the printing layer is located at the interface of the two substrates and that the two substrates can come into contact in the area of ​​the window and the peripheral area.

Claims

Demands

1. Security document comprising a body composed of at least two transparent plastic substrates (12a, 12b) and delimited by edges (16) forming a substantially rectangular surface comprising four corners, at least one of the substrates (12a, 12b) receiving a printing layer (20) opaque in the visible range and applied to the edges (16) of the document (10), The printing layer (20) delimiting a peripheral part (24) at least partially devoid of printing and forming a set of lines bordering a secure area (27) containing security information, the peripheral part (24) having a smaller unprinted dimension of between 100pm and 500pm, so that the plastic substrates (12) are in direct contact and assembled in the peripheral part (24).

2. Document according to the preceding claim, in which the peripheral part (24) is totally devoid of printing.

3. Document according to claim 1 in which the peripheral part (24) is partially devoid of printing by formation of unprinted striations (26) separated by printed edges (28).

4. Document according to the preceding claim, in which the striations (26) and the edges (28) have substantially the same smallest dimension.

5. Document according to any one of the preceding claims, wherein the secure area (27) bordered by the peripheral part (24) represents 90% of the surface of the document (10).

6. Document according to any one of the preceding claims, wherein the secure area (27) bordered by the peripheral part (24) represents less than one quarter of the surface of the document (10) and includes a security element (29) such as an engraved portrait, a printed portrait, a diffractive element.

7. Document according to any one of the preceding claims, wherein the thickness of the printing layer (20) is between 5pm and 50pm.

8. Document according to any one of the preceding claims, wherein the peripheral part (24) without printing forms a continuous pattern forming a loop on the surface of the document or a continuous pattern between two edges of the document.

9. Document according to any one of claims 1 to 7, wherein the peripheral part (24) without printing forms a discontinuous pattern.

10. Document according to the preceding claim, wherein the discontinuous pattern is formed by the association of four peripheral zones (24a, 24b, 24c, 24d) each formed in the vicinity of the four corners of the document (10) and extending substantially parallel to the edges (16).

11. Document according to any one of the preceding claims, wherein the printing layer (20) delimits an area devoid of printing so as to create a transparent window (22) in the security document.

12. Document according to any one of the preceding claims, wherein the plastic substrates (12a, 12b) are polycarbonate substrates.

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