FR3142123A1 - Security document comprising a perforated metal layer adjacent to at least part of one face of a matrix of colored sub-pixels and manufacturing method. - Google Patents

Abstract

Security document comprising a perforated metal layer adjacent to at least part of one face of a matrix of colored sub-pixels and manufacturing method. The invention relates to a security document comprising a stack of layers comprising a matrix of colored sub-pixels, a metallic layer adjacent to at least part of one face of the matrix of colored sub-pixels, in which the metallic layer comprises perforations next to sub-pixels of the matrix of colored sub-pixels. Figure for abstract: Fig. 2a.

Description

Security document comprising a perforated metal layer adjacent to at least part of one face of a matrix of colored sub-pixels and manufacturing method.

The invention relates to the field of security documents, and in particular security documents on or within which images can be observed. The invention applies non-exclusively to physical identity documents, such as a passport, an identity card, a driving license, a residence permit, etc.

The identity market today requires increasingly secure physical identity documents (also known as identity documents or security documents). This market concerns very diverse documents, such as identity cards, passports, access badges, driving licenses, etc., which can be presented in different formats (cards, booklets, etc.).

Security documents must be authenticated easily and quickly. They must also be difficult to counterfeit (if possible unfalsifiable), in the face of the latest counterfeiting techniques.

Security documents usually feature colorful images, for example photographs of the faces of a security document holder.

Colored imaging techniques for secure identity documents use arrays of colored subpixels (e.g. with Red-Green-Blue subpixels or Cyan-Magenta-Yellow subpixels) and techniques for blackening a layer which will mask portions of sub-pixels to obtain pixels of a desired color.

For example, it is known to use laserizable layers, as described in the prior document FR 2 972 553 in which a laserizable layer overcomes a matrix of colored sub-pixels.

By laserizable, we mean that the application of a laser beam to the layer (generally called laserization) generates visible gray levels by carbonization in this layer. As an indication, a laserizable layer can be a transparent polycarbonate layer and can include additives sensitive to the passage of a laser beam because this beam causes them to carbonize. Such a laserizable layer will be blackened or at least partially grayed throughout its thickness depending on the power of the laser since the additives sensitive to the passage of a laser beam are distributed uniformly throughout the thickness of the layer.

The color image formation techniques used today, such as those using laserable layers, particularly in secure identity documents, do not always make it possible to obtain satisfactory visual rendering quality. Problems particularly arise when the imaging techniques used are limited in their ability to produce certain colors. In other words, the color gamut (variety of achievable colors) of known color image formation techniques is sometimes limited.

There is a need for security documents with colored images that have a less limited color gamut.

For this purpose, the present invention proposes a security document comprising a stack of layers comprising a matrix of colored subpixels (SB, SM, SJ), a metallic layer adjacent to at least part of one face of the matrix of colored sub-pixels, in which the metal layer has perforations facing sub-pixels of the matrix of colored sub-pixels.

Thus, the invention proposes to use a metal layer which is perforated to reveal certain colored sub-pixels. It is thus possible to form pixels of the image with colored sub-pixels under or on which a metallic layer is deposited and colored sub-pixels under or on which the metallic layer is perforated, which makes it possible to have a gamut of expanded color, and especially brighter colors.

In certain embodiments, said metal layer comprising perforations is located only in a first window of said document

In this way, it is possible to make only one part of the image brighter. This advantageously makes it possible not to modify the color rendering outside the window, compared to a usual rendering of the document, which is important when said document is a security document.

In certain embodiments, said metal layer is positioned above the matrix of colored subpixels.

In certain embodiments, said metal layer is positioned below the matrix of colored subpixels.

In this way, it is possible to choose the desired rendering on the front or rear side of the document, the position of the metal layer on the front or rear side giving a different rendering in terms of brightness and contrast.

In some embodiments, the metal layer is positioned above the pixel array in one or more document windows and below the pixel array in one or more document windows.

In certain embodiments, the image displayed in said window comprises at least part of an image displayed on a second window of said document, said second window being located on an area of said document not including said perforated metal layer.

This is particularly advantageous when the document represents an identity document. Indeed, the image represented in the window can be the face of the document holder and it is particularly advantageous to print the face in a window whose color gamut is widened so as to better distinguish the details. On the other hand, displaying an image with a wider gamut makes it more difficult to falsify the document as this image includes more details.

In certain embodiments, it can be envisaged to represent information other than the face, for example personal identification information of the holder of the document, such as his marital status or information relating to the document, such as a registration number. .

In certain embodiments, it can also be envisaged to represent in the window part of the information present in another area of the document, by changing their orientation, for example by rotating this information.

In certain embodiments, said metal layer is previously partially demetallized so as to adhere to the layer(s) in which it is inserted.

This advantageously allows the layers to be sealed together more strongly because the insertion of a metal layer between two layers, such as polycarbonate for example, weakens the adhesion of the two polycarbonate layers to each other. Demetallizing part of the metal layer, even minimally, makes it possible to improve the assembly of the layers and thus the lifespan of the document over time.

In certain embodiments, said perforated metal layer is perforated so that the image displayed in said first window presents a different visual rendering depending on whether said document is illuminated from the front side or from the rear side.

The invention also relates to a method of manufacturing a security document in which a matrix of colored sub-pixels is assembled with a metal layer, adjacent to at least part of one face of the matrix of colored sub-pixels, the method further comprising forming performances through said metal layer facing sub-pixels of the matrix of colored sub-pixels.

Other characteristics and advantages of the present invention will emerge from the description given below, with reference to the appended drawings which illustrate examples of embodiment devoid of any limiting character. In the figures:

There represents a top view of a security document according to one embodiment of the invention,

There is a sectional view of security documents before perforation, according to an example,

There is a sectional view of security documents before perforation, according to an example,

There is a sectional view of security documents before perforation, according to an example,

There is a sectional view of security documents before perforation, according to an example,

There is a sectional view of the document of the after perforation,

There is a sectional view of the document of the after perforation,

There illustrates the phenomenon observed when observing the document according to certain embodiments,

There illustrates the phenomenon observed when observing the document according to certain embodiments,

There illustrates the phenomenon observed when observing the document according to certain embodiments,

There illustrates the phenomenon observed when observing the document according to certain embodiments,

There is a top view of the matrix of colored sub-pixels according to a first example,

There is a top view of the matrix of colored subpixels according to a second example.

We will now describe security documents comprising both a matrix of colored sub-pixels and a metallic layer, with a color gamut improved at least in terms of brightness on at least part of the security document.

The images formed by these subpixels are customizable images, which may be different for each document, and which may be specific to each document user.

The documents described here may be physical identity documents such as a passport, an identity card, a driving license, a residence permit, etc. In fact, the documents described here may be associated with a user, and the colored images that will be obtained may be images of the users' faces.

On the , there is shown a top view of a security document D according to one embodiment of the present disclosure. Document D includes general information, in particular information relating to the type of document, a reference or identification of the document and also personal information relating to the bearer of the document. In order to improve the security of the document D, a window F includes information whose brightness and contrast are different from the brightness and contrast of the other areas of the document D. Preferably, the contrast and brightness of the information present in window F are improved for a human eye.

According to certain embodiments, the window F includes information visible from both sides of the document D. This can be made possible by the presence of transparent layers above and below the window F. According to certain embodiments, the visual rendering of this information is different depending on whether we observe the document from its front side or its rear side.

According to certain embodiments, the window F may include information not present on other parts of the document F.

According to certain embodiments, the window F can include or include part of the information present on the document D.

According to certain embodiments, this window F can also include part of the information present on the document D in a modified manner, for example with a rotation. or on a different scale. This information can be, for example, the face of the bearer of document D, or personal data, such as his marital status, for example his date of birth, his place of birth, physical distinctive signs, etc.

According to certain embodiments, several windows F may be present on the document D. These windows may include different information in each window (or in one or more windows) or the same information in each window (or in one or more windows). showing different contrast or brightness in multiple windows.

Figures 2 to 5 illustrate embodiments in which sectional views of the document D illustrate how a different visual rendering is obtained in the window(s) F.

In Figures 2a and 2b, there is schematically represented a document 100, respectively 100' obtained by the assembly of different layers, which may have been implemented by means of lamination. Documents 100 or 100' may be a representation of document D of the .

The document 100 or 100' particularly comprises a matrix of colored sub-pixels 101, for example a transparent or opaque layer on which colored elements have been printed which each form colored sub-pixels. Here, the matrix of colored sub-pixels includes sub-pixels having three possible colors, cyan sub-pixels SB, magenta sub-pixels SM, and yellow sub-pixels SJ. Here we find the three colors of the color model well known to those skilled in the art under the Anglo-Saxon acronym CMY (“Cyan Magenta Yellow”). The invention is not limited to this color model and can also use a model such as the RGB model (“Red Green Blue” in English, i.e. Red, Green, Blue). Of course, we can use other color triplets that differ from CMY and RGB.

The subpixels are arranged according to a matrix which will be described in more detail with reference to the or to the . It can nevertheless be noted that a PM pattern of three sub-pixels SB, SM, and SJ is repeated several times in the section visible in Figures 2a to 5d.

The documents 100 and 100' also optionally include a transparent layer 103, for example made of polycarbonate, as well as a transparent layer 104, for example made of polycarbonate. These two layers can be protective layers. The transparency of these protective layers makes it possible to observe the 100 or 100' document from its front side or its rear side while viewing information present on one or the other side.

On the , a metal layer 102 was assembled above the matrix of colored sub-pixels.

On the , a metal layer 102 has been assembled below the matrix of colored sub-pixels.

This layer can be chosen so that perforations can be formed in this layer easily, for example by application of a laser beam with a given wavelength called perforation wavelength.

This layer 102 may consist of an opaque reflective metallic film, this metallic film being able for example to be produced by deposition of a metallic ink.

Thus, the present disclosure relates to a security document comprising a stack of layers comprising a matrix of colored sub-pixels, a metallic layer adjacent to at least part of one face of the matrix of colored sub-pixels, in which the layer metallic has perforations facing sub-pixels of the matrix of colored sub-pixels.

In Figures 3a and 3b, there is schematically represented a document 1000, respectively 1000' obtained by the assembly of different layers, which may have been implemented by means of lamination. Documents 100 or 100' may be a representation of document D of the .

The documents 1000 and 1000' differ respectively from the documents 100 and 100' in that the metal layer 102' is positioned on or under a part, or window, of the document 1000 or 1000' and does not cover the entire matrix of colored subpixels 101. According to certain embodiments, this metal layer 102' can be deposited on or under several parts or windows of document D.

Figures 4a and 4b show the document 1000' after a step in which perforations are formed in the metal layer 102' has been implemented. This step may include the application of a laser beam at the perforation wavelength. It should be noted that Figures 4a and 4b relate to documents 1000 and 1000', i.e. to the positioning of the metal layer on part of the sub-pixel matrix as represented by Figures 3a and 3b but of course this also applies to documents 100 and 100' as shown in Figures 2a and 2b.

At this stage, we note that certain patterns of colored sub-pixels are associated with different perforations. From left to right on the , we observe :

- A metallic layer present above a yellow sub-pixel SJ, above a yellow sub-pixel SJ and an adjacent Magenta sub-pixel SM, then above a yellow sub-pixel SJ and an adjacent Magenta SM subpixel.

From left to right on the , we observe :

- A metallic layer present below a yellow sub-pixel SJ, below a yellow sub-pixel SJ and an adjacent Magenta sub-pixel SM, then below a yellow sub-pixel SJ and an adjacent Magenta SM subpixel.

The presence of this metallic layer above or below certain colored sub-pixels makes it possible to accentuate the brightness and contrast of the image formed by the colored sub-pixels. A colored image appears when looking at the 1000 or 1000' document, with brighter colors than in the techniques according to the prior art. It can be noted that the combination of patterns and perforations forms image pixels, but, as will be described below, we call pixels those obtained after the optional laserization step. We understand that the combination of the perforated metal layer 102' makes it possible to obtain a very wide color gamut, in particular for the brightest colors.

This is explained with reference to Figures 5a to 5d. We do not detail here the effect of lighting on the portions of documents 1000 or 1000' which are not included in window F because the metal layer 102, respectively 102' is not present on these portions.

There represents a sectional view of the security document 1000 when illuminated from its rear side.

The rear face of the document 1000 is exposed to a light source and more particularly the window F. The metal layer 102' present above the first yellow sub-pixel of the window F, starting from the left, blocks the transmission of the light from the back side to the front side of the document. Thus, the yellow component is no longer present in the pixel displayed on the front face and the combination of the adjacent cyan and magenta subpixels gives a blue color whose luminance and contrast are accentuated compared to the prior art or by compared to pixels located outside the window F.

The metal layer 102' present above the second yellow sub-pixel starting from the left of the window F and the magenta sub-pixel adjacent to its left, blocks the transmission of light from the rear face to the front face of the document. Thus, the yellow and magenta components are no longer present in the pixel displayed on the front face and the combination of the adjacent cyan and yellow sub-pixels gives a green color whose luminance and contrast are accentuated compared to the prior art or compared to the pixels located outside the window F. This is also accentuated by the presence of the metallic layer above the magenta sub-pixel located to the right of the window.

There represents a sectional view of the security document 1000 when illuminated from its front face.

The front face of the document 1000 is exposed to a light source and more particularly the window F. The metal layer 102' present above the first and second yellow sub-pixels of the window F prevents the light from reaching these sub-pixels. -yellow pixels. Thus, the combination of the cyan and magenta sub-pixels located between these two yellow sub-pixels gives a pixel whose brightness is modified by this non-reflection of the light on the yellow sub-pixels framing them and gives a blue brightness with levels of gray, NVG, the presence of gray being due to the gray color of the metallic layer present on the adjacent yellow sub-pixels.

The metal layer 102' present above the second and third yellow sub-pixels starting from the left of the window F and the magenta sub-pixel adjacent to its left, prevents light from reaching these magenta sub-pixels. Thus the combination of the cyan and yellow sub-pixels located between these two magenta sub-pixels gives a pixel whose brightness is modified by this non-reflection of the light on the magenta sub-pixels framing them and gives a green brightness with levels of gray, NVG, the presence of gray being due to the gray color of the metallic layer present on the adjacent yellow sub-pixels.

We thus see that the presence of the metallic layer above the yellow or magenta sub-pixel (it would be the same if the sub-layer was located on one or more cyan sub-pixels) makes it possible to obtain a luminous rendering different depending on whether the document is illuminated by its front side or its rear side, making the reproduction of such a document more complex and thus improving its robustness in terms of security.

There represents a sectional view of the security document 1000' when illuminated from its rear side.

The rear face of the document 1000' is exposed to a light source and more particularly the window F.

The metal layer 102' present below the first yellow sub-pixel of window F, starting from the left, blocks the transmission of light from the rear side to the front side of the document. Thus, the yellow component is no longer present in the pixel displayed on the front face and the combination of the adjacent cyan and magenta subpixels gives a blue color whose luminance and contrast are accentuated compared to the prior art or by compared to pixels located outside the window F.

The metal layer 102' present below the second yellow sub-pixel starting from the left of the window F and the magenta sub-pixel adjacent to its left, blocks the transmission of light from the rear face to the front face of the document. Thus, the yellow and magenta components are no longer present in the pixel displayed on the front face and the combination of the adjacent cyan and yellow sub-pixels gives a green color whose luminance and contrast are accentuated compared to the prior art or compared to the pixels located outside the window F. This is also accentuated by the presence of the metallic layer above the magenta sub-pixel located to the right of the window. The color rendering of Figures 5a and 5c is the same.

There represents a sectional view of the security document 1000' when illuminated from its front face.

The front face of the document 1000' is exposed to a light source and more particularly the window F.

The metal layer 102' present below the first yellow sub-pixel of window F, starting from the left, increases the reflection of the yellow sub-pixel because the light can no longer pass through the yellow sub-pixel. The adjacent sub-pixel on the right lets light pass through (because layer 102' is perforated under the magenta sub-pixel) and thus we observe a predominance of the yellow color compared to the other sub-pixels. Thus, the color observed is a yellow whose luminance and contrast are accentuated compared to the prior art or compared to the pixels located outside the window F.

The metal layer 102' present below the second yellow sub-pixel starting from the left of the window F and the magenta sub-pixel adjacent to its left, increases the reflection of these two pixels because the light can no longer pass through. through these two subpixels. These two yellow and magenta sub-pixels being surrounded by blue sub-pixels under which the layer 102' is perforated, these two blue sub-pixels let the light pass. Thus, the yellow and magenta components have increased reflectivity compared to the adjacent blue sub-pixels and thus, we observe a predominance of the red color (combination of yellow and magenta). Thus, the color observed is a red whose luminance and contrast are accentuated compared to the prior art or compared to the pixels located outside the window F.

The metal layer 102' present below the third magenta sub-pixel starting from the left of the window F, increases the reflection of this sub-pixel because the light can no longer pass through. This is accentuated by the fact that layer 102' is perforated under the yellow sub-pixel adjacent to the left of the magenta sub-pixel. Thus, the color observed is a magenta whose luminance and contrast are accentuated compared to the prior art or compared to the pixels located outside the window F.

The examples in Figures 5a to 5d illustrate that the perforated metal layer advantageously makes it possible to obtain modified colors and in particular contrast and accentuated brightness. Thus, this perforated metal layer makes it possible to widen the color gamut obtained by the sub-pixel matrix in the absence of the perforated metal layer.

Advantageously, it can be envisaged to represent in the window F, an image or information already contained in another part of the document 1000 or 1000'. Indeed, when the document 1000 (or 1000') is an identity document, this document generally includes, on a surface V of the document, an image representative of the face of the holder of the document.

It may be desired to reproduce, in a window F of dimension smaller than the surface V, this image with a greater color gamut. The present disclosure can advantageously allow this reproduction. The presence of this portrait in window F improves the security of the document by making it more difficult to forge. Furthermore, as illustrated in Figures 5a to 5d, the rendering of colors being different in transmission or reflection of light on the document, this falsification is made even more complex.

It may also be desired to represent in this window F, an image or information already represented in one or more parts of the document, with for example a rotation of this information in the window F relative to their orientation in the other part of the document. document.

In some embodiments, the metal layer may be located above the pixel array in one or more document windows and below the pixel array in one or more document windows. This makes it possible to further improve the security of the document, by making its production more complex.

In order to improve the adhesion of the metal layer with adjacent layers, and for example adjacent polycarbonate layers, the metal layer can be partially demetalized beforehand in order to promote adhesion of the layers and make the document more resistant. . A demetallization of around 2% of the metal layer may be sufficient to achieve this goal.

Furthermore, we note that the transparency of the protective layers 103 and 104 in the different embodiments illustrated above can allow visualization of the information contained in the window(s) F on both sides of the document. As illustrated previously, we see that the visual rendering can also be different depending on whether we observe the document from its front side or its back side. The presence of transparent layers below and above the assembly formed by the matrix of pixels and the metal layer allows this visual rendering. The presence of transparent layers on the other parts of the document or on all other parts of the document is optional, at least on both sides. When the window includes a part, modified or not, of content reproduced on another part of the document, then it is necessary that this other part is visible and that the document therefore also includes a transparent layer at this part so that this content is visible by observing at least one of the two sides of the document.

On the , we have shown a top view of a first example of the matrix of colored subpixels 101.

Here, colored lines are aligned in groups of three colors, i.e. three lines.

On the , we have shown a top view of a second example of the matrix of colored sub-pixels 101.

Here, colored subpixels are arranged in the form of a mosaic by alternating cyan, magenta and yellow subpixels in each row and column.

Other examples of sub-pixel matrix are of course possible in the context of the present disclosure.

The arrangement examples in Figures 6 and 7 are given as an example of an arrangement representation of the sub-pixel matrix and can be used in the sub-pixel matrices shown in Figures 1 to 5.

Claims (13)

Security document comprising a stack of layers comprising a matrix of colored sub-pixels (SB, SM, SJ), a metallic layer adjacent to at least part of one face of the matrix of colored sub-pixels, in which the layer metallic has perforations facing sub-pixels of the matrix of colored sub-pixels. Document according to claim 1 wherein said metal layer comprising perforations is located only in a first window of said document. Document according to one of the preceding claims in which said metal layer is positioned above the matrix of colored sub-pixels. Document according to one of the preceding claims in which said metal layer is positioned below the matrix of colored sub-pixels. Document according to one of claims 2 to 4 in which the image displayed in said window comprises at least part of an image displayed on a second window of said document, said second window being located on an area of said document not including said perforated metal layer. Document according to one of the preceding claims in which said metallic layer is previously partially demetallized so as to adhere to the layer(s) between which it is inserted. Document according to one of the preceding claims in which said perforated metal layer is perforated so that the image displayed in said first window presents a different visual rendering depending on whether said document is illuminated from the front side or from the rear side. Method of manufacturing a security document in which a matrix of colored sub-pixels is assembled with a metal layer, adjacent to at least part of one face of the matrix of colored sub-pixels, the method further comprising: formation of perforations through said metal layer facing sub-pixels of the matrix of colored sub-pixels. Manufacturing method according to claim 8 in which said metal layer is assembled only in a window of said document. Manufacturing method according to one of claims 8 or 9 in which said metal layer is positioned above the matrix of colored sub-pixels. Manufacturing method according to one of claims 8 or 9 in which said metal layer is positioned below the matrix of colored sub-pixels. Manufacturing method according to one of claims 8 to 11 in which said metallic layer is previously partially demetallized so as to adhere to the layer(s) in which it is inserted. Manufacturing method according to one of claims 8 to 12 in which the formation of perforations is obtained by laserization of the metal layer.