FR3050140A1 - SAFETY DOCUMENT WITH LASER PRINTING THROUGH OPAQUE INK - Google Patents

Abstract

The invention relates to a security document, comprising a multilayer complex (9) formed by at least four layers (1,2,6,5), namely in order from the outside of the document, an upper layer transparent lens (1), an intermediate layer (2) transparent, an inner layer (6) transparent and sensitive to a laser beam to allow the laser inscription of a code or an image (7). ) in this layer (6), and a layer (5) opaque to visible light, characterized in that said transparent intermediate layer (2) comprises at least one printed area (3) with an ink opaque to visible light but leaving passing said laser beam without altering the ink of said printed area (3).

Description

FIELD OF THE INVENTION The invention relates to the field of security documents such as contactless or contactless smart cards, or plastic cards, even without a chip. , in particular those in formats known as ID1 (credit card format), ID2 which corresponds to twice ID1 (format of French national identity cards), and ID3 (format of passports). To simplify the presentation, the term "card" or "document" will be used equivalently to designate all the cards or documents of the aforementioned type.

State of the art:

Most smart cards or other known security documents have a generally multilayered card body, having at least one layer of opaque material whose surface corresponds to the total area of the document or card. This allows to hide in the body of the document or card any microelectronic components such as a chip, one or more antennas etc. It also allows to present a maximum area of card or document that can be the subject of a graphic personalization, namely the printing of information relating to the holder or the use of the card or document.

Some of the known cards have a transparent window in all the layers, which makes it possible to see by transparency a security pattern printed on one of the inner layers of the card.

One of the problems posed by existing security documents, in particular by transparent window cards, is that it is possible to cut out and remove the security reason, or the transparent window including the security information that may be engraved there, for report it in another document which is otherwise a counterfeit document.

In addition, known window cards often suffer from an aesthetic problem, because at the window, a slight creep of the layers of the lamination process can give the edge of the window a blurred and non-uniform appearance.

Cards are also known whose pattern or security code is hidden behind an ink pad. But the inks used are thermochromic inks which are applied using various printing processes (offset, flexographic, screen printing, flexible typography) and very thin layer, of the order of 4 to 6 micrometers. Because of their fineness, these layers are not very opaque, so that it remains possible to see the security code or pattern with the naked eye, possibly using a low light.

OBJECTS OF THE INVENTION: The general object of the invention is to propose a new security document structure, in particular of a smart card or a chipless card, capable of solving the disadvantages of known multilayer cards or documents, in particular those provided. a transparent window and a security pattern disposed within said window. The invention will be described more particularly in the context of a form factor corresponding to that of a chip card in ISO 7816-1 format, also called ID1 format, but it is quite clear that it applies to other formats and other types of security documents. The invention is more particularly intended to provide a multilayer card capable of providing enhanced protection of the security data etched inside the layers, and to make it much more difficult to take a code or security reason for the reporter. in another card.

Another object of the invention is to provide a map provided with a window, capable of creating, for certain modes of observation, a visual break with the rest of the map. In addition, this visual break should preferably be of such a nature as to reinforce the card's resistance to counterfeiting by making it possible to integrate security reasons of 1st, 2nd, and 3rd levels.

In this respect, it is recalled that security levels of security elements are classified on several levels.

A security element is said to be level 1 if it is visible to the naked eye in ambient light.

A security element is said to be level 2 if it is not detectable to the naked eye and if its detection requires a simple exterior detection tool, such as a 365nm UV lamp, or a magnifying glass x8.

A security element is said to level 3 if it is not detectable to the naked eye and if its detection requires a microscope or very specific equipment called laboratory.

Concretely, the invention therefore relates to a security document, possibly provided with a window transparent to light during a normal observation, and comprising one or more solid areas or ink blocks printed opaque to visible light, and through however, it is possible to write laser information in a layer under the printed solid area.

OBJECT OF THE INVENTION The object of the invention is therefore a security document, comprising a multilayer complex formed by at least four layers, namely in order from the outside of the document, a protective upper layer. transparent to visible light, an intermediate layer also transparent, an inner layer also transparent and sensitive to a laser beam to allow the laser inscription of a code or an image in this layer, and a layer opaque to light visible, characterized in that said transparent intermediate layer comprises at least one printed area with an ink opaque to visible light but passing said laser beam without altering the ink of said printed area.

Preferably, said ink-filled printed area is located on the upper face of the transparent intermediate layer, in contact with the upper protective layer.

Advantageously, said code or said security image is laser-inscribed in an area of the inner layer under said printed area, facing it. This makes it possible to hide all or part of the code or image in direct view.

According to the invention, the layers of the document are made of polycarbonate, and said ink is also based on polycarbonate, which allows it to integrate better with its support layer during the lamination of the layers. In addition, the ink has the property of being transparent to certain laser beams.

Preferably, said laser inscription is then performed using a laser, in particular a YAG laser of 1064 nanometers wavelength.

When the security document is in the form of a card in ISO 7816-1 format, the upper protective layer will have a thickness between 50pm and 100pm, the transparent intermediate layer that carries the opaque printed area will have a thickness between 150pm and 300pm, the transparent inner layer that receives the laser inscription will have a thickness between 50pm and maximum 100pm, and the opaque layer will complement and have a thickness between 430pm and 340pm.

According to the invention, said ink is printed by screen printing and not by offset or other printing methods, and it has a thickness of between 9 and 40 microns, ensuring high opacity to visible light, while allowing no damage. the laser beam, which makes it possible to personalize the cards or documents with codes or security information at the last manufacturing stage.

According to one embodiment, this opaque layer comprises a window filled with a material transparent to visible light, said window being disposed under an area of the inner layer printed with said transparent laser ink.

Preferably, the area printed with the ink pad has a non-printed, ink-free, unprinted resist area so as to define a first area of the opaque layer window that is visible to the naked eye since outside the document. In this way, it is possible to provide the security document with a security code or security image printed with a laser beam on the transparent inner layer and located partly in the area of the reserve so as to be visible from the outside, and partly under the printed area with the laser-transparent ink but out of the area of the reserve, so that part of the code or image is visible to the naked eye from the outside of the document, but another part remains invisible to the naked eye.

According to an even more advanced variant of the invention, the security document comprises, on either side of said opaque layer, two stackings of layers each constituted, in order starting from the outside of the document, by a transparent upper layer of protection transparent to visible light, a transparent intermediate layer provided with one or more zones printed with an opaque ink with visible light but transparent for a laser beam, and a transparent inner layer sensitive to a laser beam for allow the laser inscription of a code or an image in this layer.

In this way, the security document will comprise two opaque ink blocks on either side of the opaque layer, and two complementary laser inscriptions under the respective blocks. This structure will be even more difficult to counterfeit since it multiplies the layers provided with specific elements, namely an opaque layer with a particular window, delimited in part by a specific ink pad on each side of the opaque layer, and a specific laser marking in distinct transparent layers on each side of the opaque layer.

Of course, the security document according to the invention is in any format adapted to the needs, in particular in the form of a card in the format called ID1, or in the form of a card in the format called ID2, or in the form of a passport booklet in the so-called ID3 format.

In addition, the laser-transparent ink can be either monochrome, or multi chrome. The invention also relates to a method of manufacturing a security document as described above, comprising steps of assembling by rolling or gluing a set of transparent or opaque layers superimposed, based on polycarbonate, characterized in that it comprises: a step consisting, prior to assembling the layers, to print on at least one area of a transparent intermediate layer, an ink block opaque to visible light but transparent to a laser beam; a step consisting, subsequent to the assembly of the layers, in registering with a laser beam passing through said ink, a security information or an image, in a transparent inner layer located, with respect to the outside, under said transparent intermediate layer. The invention will be better understood on reading the description with the aid of the drawings, in which: FIG. 1 represents an exploded perspective view of a first embodiment of the card according to the invention; - Figure 2 shows a cross-sectional view of a card according to Figure 1; FIG. 3 represents a plan view of a card according to FIG. 1. Detailed description:

Referring to FIG. 1, there is shown a card structure composed of a multilayer complex 9, which comprises on the one hand several layers 1, 2, 6 of transparent plastics material, some of which, like the inner layer 6, can react with a laser beam to reveal black or half-gray markings, in a manner known per se. The multilayer complex 9 also comprises a layer 5 opaque to visible light.

The outer transparent layers 1 are layers also called "overlay", which have a simple role of mechanical protection of the underlying layers against scratches and others.

The intermediate layer 2 is essentially transparent, but partially printed, preferably on its upper face in contact with the outer layer 1, with a block or flat of an ink which has the particularity of being opaque to visible light, but sufficiently transparent to certain laser beams, to be able to write a laser code or image in an inner layer (relative to the outer layers 1) through this layer, without damaging or interfering with the printed block 3.

The inner layer 6 of the complex 9 is a transparent layer that has a laser-inscribed security code or image in an area of this inner layer 6 located under said printed area 3, so that the code or image 7 registered by laser is next to the printed area 3.

The four 1,2,6,5 layers of the complex 9 are made of polycarbonate, and the ink of the printed area 3 is also based on polycarbonate, which ensures a better homogeneity of the product. The inscription in the transparent inner layer 6 by means of a laser beam is preferably carried out using a YAG laser of 1064 nanometers in wavelength, commonly used for the laser marking of plastic products. The YAG 1064 nanometer laser is commonly used for black or grayscale engraving on polycarbonate or brown on PVC, so the process is easy to master. The ink of the printed area 3 is printed by screen printing and has a thickness of between 9 and 40 microns, which gives it a high degree of opacification with respect to visible light. It can be monochrome, or polychrome.

In a more evolved version, corresponding to the figures, and which combines multiple advantages, the document according to the invention comprises, a central opaque layer 5, and on both sides of the opaque layer 5, two sets of transparent layers 1 , 2.6 as described above.

When the opaque central layer 5 comprises a window 4, it is useful for the printed areas 3 to be opposite the window 4. In order to avoid problems of flatness defect on the finished product, the window 4 is filled with a transparent material of the same thickness as the opaque layer 5.

The printed zone 3 situated opposite the window 4 comprises one or more reserves 8, devoid of ink, which make it possible to see the information (code or image) 7 inscribed with the laser, at the level of the reserves, in the transparent inner layers 6.

Another advantage of the reserves 8 is to be able to visually delineate very clearly, a portion of the window 4, whose contours possibly irregular due to the manufacturing process, will then be invisible.

It is also conceivable to give reserves 8, by a simple screen printing process, any form specific to the manufacturer of the card, or the intended application. It may be a logo, or any safety graphics, which will eventually visually complement the laser printed information 7 in the transparent inner layers 6.

In addition, it is possible to judiciously place the reserves 8 of the ink pads 3 of two layers 2 superimposed, facing one another, in order to see the same information 7 laser engraved from each side of the document. Alternatively, the reserves 8 of two superimposed ink blocks 3 may be offset relative to one another to allow differentiated information to be seen according to the viewing side of the document. This allows a very large number of combinations of viewing or masking of laser burned security information in the inner layers 6.

For example, a piece of information 7 may be located partly in the zone of the reserve 8 so as to be visible from the outside, and partly situated outside the reserve 8 and masked under the printed area 3 with the opaque ink. But many other combinations are possible.

The thicknesses of the layers are exaggerated in the figures for the sake of clarity. They may vary according to the needs of the construction of the security document. When the document will be a standardized map, the layers will be chosen to obtain contact or contactless smart cards compatible with the dimensions of the ISO 7816-1 standard (card thickness ranging from 680 micrometers to 840 micrometers).

Advantages of the invention: The invention achieves the goals set. In particular, it makes it possible to propose a security document, in particular a smart card, which is particularly difficult to counterfeit. In particular, depending on the lighting conditions, the reserve 8 catches the eye and allows the development of visible or hidden security elements.

In addition, the flat ink 3 can hide the contours of the main window 4, which are often irregular due to a certain creep of the rolling process of the layers.

Thanks to the special ink of solids, it is possible to laser engrave through solid colors in the personalization phase of texts and patterns 7 to make them non-visible and therefore not falsifiable.

In addition, it is possible to modulate the sizes of the reserves by an ink printing process by screen printing, and not with cutting tools that leave traces. The realization of a window according to the needs in shape and size on the part of the customer is facilitated.

Moreover, it is possible to mark part of a security code 7 in a first layer 6 from a first face of the document, and another part of the code 7 (or another code) is written in another layer 6 from the second side, which makes the reproduction of a falsified card even more difficult.

It is also possible to diversify the security uses, depending on the number of ink pads, windows, and their respective locations. Thus, it would be possible to have on a layer 2 several printed areas 3, some without reserve to hide a first security information 7, and some with a reserve 8 to reveal other security information, and the various security information 7 can be correlated or complementary to enhance the overall safety of the product.

In addition, the entire structure being polycarbonate, including the ink, it fuses with the polycarbonate adjacent layers during lamination for more cohesion of the whole.

Thanks to the reserve 8 arranged in the printed ink zone, it is possible to infinitely customize the appearance (size, shape) of an underlying main window 4. In addition, the method is independent of the document format, and applies to all types of documents and to various and varied uses.

Furthermore, the implementation of the invention is simple, it does not require modifications of the production lines. Figure captions: 1. Transparent layer (overlay) 2. Transparent intermediate layer, printed 3. Opaque ink surface 4. Transparent window 5. Opaque layer 6. Transparent inner layer, sensitive to laser 7. Laser engraving 8. Reserve 9 Multilayer complex

Claims (14)

1 - Security document, comprising a multilayer complex (9) formed by at least four layers (1,2,6,5), namely in order from the outside of the document, a top layer of protection ( 1) transparent to visible light, an intermediate layer (2) transparent, an inner layer (6) transparent and sensitive to a laser beam to allow the laser inscription of a code or an image (7) in this layer (6), and a layer (5) opaque to visible light, characterized in that said transparent intermediate layer (2) comprises at least one printed area (3) with an ink opaque to visible light but passing through said beam laser without altering the ink of said printed area (3). 2 - Security document according to claim 1, characterized in that said printed area (3) is printed on the upper face of the transparent intermediate layer (2) in contact with the upper protective layer (1). 3 - Security document according to claim 1 or claim 2, characterized in that said transparent inner layer (6) comprises a code or security image registered by laser in an area of this layer under and next to of said printed area (3) of the intermediate layer (2). 4 - Document according to any one of the preceding claims, characterized in that the four layers (1,2,6,5) of the multilayer complex (9) are made of polycarbonate, and in that said ink is also based on polycarbonate . 5 - Document according to any one of the preceding claims, characterized in that said laser inscription (7) is performed using a YAG laser of 1064 nanometers wavelength. 6 - security document according to any one of the preceding claims, characterized in that said ink is printed by screen printing and has a thickness between 9 and 40 microns. 7 - Security document according to any one of the preceding claims, characterized in that said opaque layer (5) comprises a window (4) filled with a material transparent to visible light, said window (4) being disposed under a zone (3) the transparent intermediate layer (2) printed with said transparent laser ink. 8 - security document according to claim 7, characterized in that the printed area (3) located opposite the window (4) of said opaque layer (5) comprises a reserve (8) transparent and free of ink, delimiting a first area of the window (4) visible to the naked eye from outside the document, and a second area of the window (4) located under the ink and invisible to the naked eye. 9 - Security document according to claim 8, characterized in that it comprises a security code or a security image, printed (e) using a laser beam on the transparent inner layer (6), and located partly in the area of the reserve (8) so as to be visible from the outside, and partly under the printed area (3) with the laser-transparent ink, but out of the area of the reserve (8) so as to remain invisible to the naked eye from outside the document. 10 - Security document according to claim 9, characterized in that it comprises a security code or a security image, printed (e) using a laser beam on the transparent inner layer (6), and located partly in the area of the store (8) so as to be visible from the outside, and in that the transparent intermediate layer (2) has a first area (3) printed with said opaque ink, and a second area (3) printed with said opaque ink, said code or said security image being printed partly under said first printed area (3) and under said second printed area (3). 11 - Security document according to any one of the preceding claims, in the form of a map in ISO 7816-1 format, characterized in that the upper protective layer (1) has a thickness between 50pm and ΙΟΟμιτι, the transparent intermediate layer (2) which carries the opaque printed area (3) has a thickness between 150pm and 300pm, the transparent inner layer (6) which receives the laser inscription (7) has a thickness between 50pm and maximum 100pm, and the opaque layer (5) has a thickness between 340pm and 430pm. 12 - security document according to any one of claims 1 to 10, characterized in that it comprises, on either side of said layer (5) opaque, two stacks of layers each consisting, in order of from the outside of the document, by a protective upper layer (1) transparent to visible light, a transparent intermediate layer (2) provided with one or more zones (3) printed with an ink opaque to visible light but transparent for a laser beam, and an inner layer (6) transparent and sensitive to a laser beam to allow the laser inscription of a code or image (7) in this layer. 13 - Security document according to any one of the preceding claims, characterized in that it is in the form of a map format ID1 corresponding to ISO 7816-1, or in the form of a map in the so-called ID2 format corresponding to twice the format ID1, or in the form of a passport booklet in the so-called ID3 format. 14 - A method of manufacturing a security document according to any one of claims 1 to 13, comprising steps of assembling by rolling or gluing a set of transparent layers (1,2,6) and opaque (5) superposed, based on polycarbonate, characterized in that it comprises: a step consisting, prior to assembling the layers, to print on at least one area (3) of an intermediate layer (2), an opaque ink to light visible but transparent to a laser beam; a step consisting, after the assembling of the layers, in registering with a laser beam passing through said ink, a security information or an image, in a transparent inner layer (6) located, relative to the outside, under said transparent intermediate layer (2).