Identity document with fluorescent pattern

Abstract

The invention relates to an identity document 10 formed by assembling at least three substrates, the substrates being laminated together, the three substrates being constituted respectively by an opaque white substrate, a first transparent substrate 16 and a second transparent substrate 18, the second substrate 18 being sandwiched between the opaque white substrate 20 and the first substrate 16, the first and second substrates 16, 18 being constituted by polymer materials, with a thickness of between 50 µm and 300 µm, a color pattern 24 with a surface area smaller than that of the substrates, the color pattern 24 being delimited by a color contour 26 and being positioned at the interface of the two transparent substrates 16, 18.The second transparent substrate 18 forms a diffusion layer and the document further comprises a fluorescent pattern 12 produced by printing a fluorescent ink sensitive to Ultra-Violet radiation, the fluorescent pattern 12 being deposited at the interface of the first and second substrates 16, 18, under the color printing pattern, and the fluorescent pattern 12 having a fluorescent contour 22 of which at least a portion extends beyond the contour 26 of the color pattern 24. [Fig. 1].

Description

Title of the invention: Identity document with fluorescent pattern

[0001] The invention relates to identity documents forming a laminated assembly consisting of several polymer substrates. The invention particularly relates to identity documents in which at least one of the substrates accommodates materials having fluorescent effects sensitive to certain light radiation such as ultraviolet radiation.

[0002] It is known from the prior art to use inks having fluorescent properties, that is to say inks capable of emitting in the visible spectrum from a light source in the UV wavelength spectrum. These inks are used in many fields including identity documents. These inks become visible and brighter when exposed to radiation in the ultraviolet wavelength spectrum. Often these inks are invisible in the visible wavelength spectrum, but they can also be white or colored in the visible radiation spectrum.

[0003] Document EP3685311 describes a document support comprising authentication means formed by encrypted security images formed by a fluorescent ink that can be revealed by a specific tool emitting a determined illumination. The security images are captured under illumination such as ultraviolet radiation under which the fluorescent ink forming the secure image is luminescent. The encrypted data can be included in the image or in the bibliographic data of the document and are revealed under exposure to the ultraviolet radiation.

[0004] The invention aims at a new use of inks having fluorescent properties. More particularly, it aims at producing a fluorescent pattern making it possible to highlight an image different from the pattern printed with fluorescent ink. It is therefore a question of using the fluorescent properties to highlight an image distinct from the fluorescent pattern itself.

[0005] For this purpose, the invention relates to an identity document formed by the assembly of at least three substrates, each having the same surface, the substrates being laminated together, the three substrates being constituted respectively by an opaque white substrate, a first transparent substrate and a second transparent substrate, the second substrate being sandwiched between the opaque white substrate and the first substrate, the first and second substrates being constituted by polymer materials, with a thickness of between 50 μm and 300 μm, the document comprising a color pattern with a surface area smaller than that of the substrates, the color pattern being delimited by a color contour and being positioned at the interface of the two transparent substrates, the color pattern (24) being formed by a matrix of sub-pixels (28a, 28b, 28c) each having a different color, and the first and / or second transparent substrate (16, 18) being sensitive to IR laser radiation (YAG), and the first substrate (16) comprising selectively blackened areas above the matrix of sub-pixels (28a, 28b, 28c) so as to extinguish certain color sub-pixels so as to generate a personalized color pattern, the second transparent substrate forms a diffusion layer, and the document further comprises a fluorescent pattern produced by printing a fluorescent ink sensitive to Ultra-Violet radiation, the fluorescent pattern being deposited at the interface of the first and second substrates, under the color printing pattern, and the fluorescent pattern having a fluorescent contour of which at least a portion extends beyond the contour of the color pattern.

[0006] Thanks to these provisions, an identity document or a card according to the invention comprises a fluorescent ink associated with a structure making it possible to improve the visual rendering of the fluorescent effect of the ink. The ink, thanks to its fluorescent properties, will absorb the incident UV light radiation to restore it in the form of fluorescent light giving a brilliant effect. The association of this ink with a specific structure of the card body, in particular with the substrate forming a diffusion layer, has the consequence of improving the brilliance effects and thus of highlighting the color pattern located opposite the fluorescent ink.

[0007] According to other characteristics: the outline of the fluorescent pattern represents a homothety by enlargement of the outline of the color pattern, the UV-sensitive ink is a fluorescent white ink, the document further comprises a third and fourth transparent substrate assembled on the side opposite the first and second substrate, the opaque layer is opaque under ambient lighting in the visible and ultraviolet wavelengths.

[0008] The invention also relates to a method for verifying an identity document, this method comprising a first step of exposing the identity document to ultraviolet radiation, then a second step of reading the color pattern, and a third step of comparing the color pattern with another piece of data on the identity document.

[0009] The present invention will be described with reference to the appended figures in which

[0010] [Fig-1] represents a sectional view of the invention,

[0011] [Fig. 1b] represents a sectional view of the identity document illuminated under radiation and a schematic representation of the path of the light rays

[0012] [Fig.2] represents a front view of a document with fluorescent ink under UV lighting,

[0013] [Fig.3] represents the document of [Fig.2] pre-personalized with the creation of a color pattern,

[0014] [Fig.4] represents the document of [Fig.3] in which the color pattern is personalized

[0015] In the representation of the drawings, scales and proportions are not respected in order to increase the clarity of the figures. Furthermore, in the figures listed above, similar features may have the same reference.

[0016] The identity document according to the invention may be an identity card, a driving license, a bank card, a credit card, an identity card, an official document in the form of a booklet, such as a passport. These identity documents are linked to the holder of the document and may be used to verify the identity of their holder or to carry out an action, such as a transaction, in the name of the holder of the document.

[0017] Typically, these identity documents comprise a flat body delimiting an upper face and a lower face having a surface area specified by established standards, such as the ID-1 format specified in ISO7810 having the dimensions 85.60mm*53.98mm. The body is formed by one or more layers of PC (polycarbonate), PVC, PET, PETf, PETg or any other polymer material traditionally used in identity documents or any combination of these materials. Typically, one face of the identity document has a first portrait such as an official photo of the document holder, this first portrait complying with certain specific government regulations.

[0018] As can be seen in the figures, the identity document 10 according to the invention comprises a fluorescent ink. Fluorescent inks have particular properties depending on the light projected onto their surface. When light strikes a fluorescent ink, some of the incident light rays, in particular ultraviolet rays, are absorbed by the fluorescent ink and are restored as brighter visible radiation. It is thus possible to obtain brightness effects using fluorescent inks.

[0019] [Fig. 2] illustrates a fluorescent pattern 12 printed with a white fluorescent ink. This fluorescent pattern 12 is visible to the user under ambient light, i.e. the visible radiation spectrum. The ink of the fluorescent pattern 12 is chosen to be white in the visible range. When Ultra-Violet radiation is applied to the fluorescent pattern 12, part of the radiation is absorbed and, in return, the ink of the fluorescent pattern 12 emits a light ray in the visible spectrum, this light ray being brighter. The ink of the fluorescent pattern 12 shown in [Fig.2] is chosen to be white so as to have a higher brightness. In fact, white reflects a large part of the light radiation into the visible, which gives a more brilliant effect.

[0020] The invention relates to the particular association of the pattern 12 with white fluorescent ink with a particular structure 14 of an identity document 10, a schematic view of which, in section, is shown in [Fig. 1]. This specific structure 14 allows the ink of the fluorescent pattern 12 to be exposed to a greater quantity of light radiation, and consequently to absorb, in absolute value, a greater quantity, and thus to emit a more intense, i.e. brighter, fluorescent light.

[0021] The structure 14 of the identity document 10 comprises at least three polymer substrates 16, 18, 20, as visible in [Fig.l]. The polymers usually used are ABS, Polycarbonate, PVC or PET and its derivatives PETg and PETf. The three substrates 16, 18, 20 are assembled by lamination, that is to say under pressure and at high temperature, so that a fusion of the materials at the interface of the substrates 16, 18, 20 allows adhesion of the substrates 16, 18, 20 to each other. The three substrates 16, 18, 20 have the same surface corresponding to the dimensions ID-1, that is to say 85.60mm*53.98mm specified in the standard ISO / IEC 7810:2003 “identification cards - physical characteristics”.

[0022] The three substrates of the invention consist respectively of a first 16 and a second 18 transparent substrates and an opaque substrate 20 of white color. The white opaque substrate 20 is opaque under ambient light, under normal lighting conditions in the visible and ultraviolet wavelengths. The second transparent substrate 18 is positioned between the white opaque substrate 20 and the first transparent substrate 16. The first and second substrates have a thickness of between 50 pm and 300 pm, preferably between 100 pm and 200 pm. The first and second substrates are transparent, that is to say that light passes through them and this light is also diffused in the thickness of the first and second substrates 16, 18.

[0023] According to the invention, the pattern 12 produced with fluorescent ink is positioned at the interface of the first and second transparent substrates 16, 18. As indicated above, it is recalled that a fluorescent ink has absorption properties. A color pattern 24 is also positioned at the interface of the first and second substrates 16, 18.

[0024] Thanks to this arrangement, the light rays are dispersed in the structure, as shown schematically in [Fig.lb]. In fact, the light rays in the UV radiation spectrum, coming from an external source, arrive at the structure 14 of the identity document and pass through the first substrate 16 where they are transmitted by diffraction. When the incident UV radiation strikes the first transparent substrate 16, the ray is transmitted through this first substrate 16 with a propagation direction deflected by refraction.

[0025] Certain rays having passed through the first substrate 16 reach the fluorescent pattern 12. The UV rays strike the fluorescent pattern 12 and are then absorbed by the fluorescent pattern 12 which returns them in the form of visible radiation giving the fluorescent ink a brighter appearance.

[0026] Then the ray continues its movement and enters a new medium constituted by the second transparent substrate 18. The light ray forms a wave which propagates in the thickness of the second substrate. The ray passes through the thickness of this second substrate 18 with a propagation direction modified by refraction. Furthermore, simultaneously with the transmission phenomenon, the light ray undergoes a diffusion phenomenon in the thickness of the second transparent substrate 18. A portion of the light ray is diffused in the thickness of the second transparent substrate 18.

[0027] Then the rays strike the white opaque layer which absorbs a small part of the radiation and reflects a large part of it.

[0028] The light rays reflected by the white opaque layer pass through the second transparent substrate 18 again, in a direction opposite to the forward direction, and are diffused in this propagation medium formed by the second transparent substrate 18. This makes it possible to distribute the UV light rays in the second substrate, until they reach the fluorescent pattern 12. The UV rays are then absorbed again by the fluorescent pattern 12 and are restored in fluorescent form.

[0029] It follows from the above description that the fluorescent pattern 12 receives both the UV radiation arriving directly from the external UV radiation emission source and also the UV rays diffused in the second substrate 18 in different directions. The fluorescent pattern 12 thus absorbs UV rays directed towards it and coming from different directions, which gives it a greater emission of fluorescent light energy.

[0030] The opaque substrate 20 is chosen to be white so as to reflect a large part of the rays, only a small part being absorbed. In addition, thanks to the diffusion of the light arriving in the second substrate, the entire surface of the opaque substrate 20 is struck by the diffused rays, and therefore reflects these rays from its entire surface, thus giving a brighter background. In addition, the UV light rays transmitted and diffused in the direction of the fluorescent pattern 12 are then absorbed by the latter and restored by the fluorescent pattern 12 itself in the form of brighter visible radiation.

[0031] Similarly, when the document is subjected to radiation in the visible spectrum, the visible radiation passes through the first and second transparent substrates 16, 18, a portion of the radiation is transmitted through the first and second transparent substrates 16, 18 and another portion of the visible radiation is diffused in the thickness of the first and second substrates. This allows the user to view the different colors of the color pattern 24.

[0032] When the visible rays strike the interface formed by the opaque white substrate 20 and the second transparent substrate 18, each ray is then reflected. Indeed, at this interface, a material is chosen capable of reflecting the incident radiation as much as possible. For this purpose, a white color will be chosen, this color not absorbing or absorbing little of the incident light rays, and having a high reflection coefficient. The reflected visible rays then propagate in the first transparent substrate 16 by diffusion and by refraction. These arrangements allow the user to view the color pattern 24 in a less darkened manner. Indeed, the white opaque layer makes it possible to provide a lighter and less gray tint for the color pattern 24.

[0033] The fluorescent pattern 12 is formed by a uniform and solid deposition of the fluorescent ink and is delimited by a first contour 22. The fluorescent pattern 12 has a uniform and continuous white color, of sufficient thickness to be opaque under ambient light. The ink of the fluorescent pattern 12 is deposited to a thickness of approximately 30 μm, and the white shade is chosen so that the fluorescent pattern 12 is opaque under normal lighting conditions in the visible range.

[0034] The identity document 10 according to the invention further comprises the color pattern 24 printed on the white fluorescent pattern 12. As visible in [Fig. 3], this pattern is made up of a matrix of pixels 28 formed of sub-pixels 28a, 28b, 28c each having three different colors. It could be considered any other form of image or color pattern 24, such as a face or a coat of arms of a country. The color pattern 24 is produced inside the contour 22 of the fluorescent pattern 12. The fluorescent pattern 12 and consequently the color pattern 24 has a surface area smaller than the surface area of ​​the identity document. Preferably, the contour 26 of the color pattern 24 is similar to that of the fluorescent pattern 12, in a larger proportion. Preferably the contour 22 of the fluorescent pattern 12 represents a homothety by enlargement of the contour 26 of the color pattern 24.

[0035] Thanks to the arrangement of the structure 14 described above and the fluorescent pattern 12, the color pattern 24 will benefit from the luminosity emitted by the fluorescent pattern 12 and thus the colors of the color pattern 24 will appear more intense and less dark.

[0036] The invention is of particular interest for the color images generated from the color matrix of [Fig. 3] whose pixels 28 are partially extinguished or hidden by a blackening 30 produced above a zone of the matrix so as to form a personalized color pattern 24bis shown schematically in [Fig. 4].

[0037] The blackening 30 above the color pattern 24 forming the matrix is ​​obtained in the thickness of the first transparent substrate 16, as shown in [Fig.l]. For this purpose, the first transparent substrate 16 is doped so that this first substrate 16 is sensitive to a particular radiation and blackens at the location where a radiation strikes the first substrate 16. More specifically, this second radiation is an Infra-Red IR radiation, emitted by a YAG type laser.

[0038] Indeed, it is known from documents EP2580065 and EP2681053 to print on a support a matrix of pixels composed of color sub-pixels and to form gray levels, or blackening, by laser carbonization in a laserizable layer located opposite the matrix of pixels, so as to reveal a personalized color image which is difficult to falsify or reproduce.

[0039] The invention uses the method described in the previously cited patents in order to carbonize the thickness of the first substrate 16. For this purpose, the first substrate 16 is formed from a doped polymer material to be sensitive to the IR radiation of the laser radiation emitted by a YAG type laser.

[0040] According to a variant embodiment not illustrated, the blackening of zones opposite the sub-pixels can be carried out under the sub-pixels, that is to say in the thickness of the second substrate. It is then possible to generate color images from the color matrix whose pixels are partially extinguished by a blackening carried out below a zone of the matrix so as to form a personalized color pattern. For this purpose the second transparent substrate is doped so that this second substrate is sensitive to the second infrared radiation IR, emitted by a YAG type laser, and blackens at the location where radiation strikes the second substrate.

[0041] According to another variant, not shown in the figures, the first substrate as well as the second substrate are doped so as to be sensitive to infrared radiation. It is then possible to blacken areas below and above the pixels so as to generate a color image.

[0042] From the arrangement of pixels 28, these pixels 28 themselves comprising a plurality of colored sub-pixels 28a, 28b, 28c, and from the blackening zone 30 above the selected sub-pixels 28a, 28b, 28c, it is possible to modify the relative colorimetric contribution of the sub-pixels 28a, 28b, 28c with respect to each other in at least part of the pixels 28.

[0043] The modification of the colorimetric contribution (or weight) of sub-pixels 28a, 28b, 28c with respect to the neighboring sub-pixels 28a, 28b, 28c in the pixels 28 corresponding allows to reveal a personalized color image or pattern 24bis, from the combination of the pixel arrangement 28 and the blackout zones 30.

[0044] The embodiment illustrated in [Fig.4] aims to form an image forming a face of the document holder. But it may be entirely possible to generate another image such as a coat of arms of a country, or even a numerical value.

[0045] The image obtained by the selective carbonization of areas corresponding to sub-pixels 28a, 28b, 28c of color makes it possible to generate a visual effect where the user will see a color image appear. However, the blackening 30 of the pixels 28 tends to darken the image. The invention makes it possible to make the image obtained brighter and more vivid by adding the fluorescent pattern 12. Indeed, when the latter is illuminated by UV radiation, it will emit a brighter and more vivid white which will itself illuminate the color image generated by the technology described further on.

[0046] In order to benefit as much as possible from the lighting effect of the fluorescent pattern 12, the white fluorescent pattern 12 has an outline 22 similar to that of the color pattern 24. Preferably, the outline 22 extends beyond the color pattern 24 over its entire circumference. Preferably, the outline 22 of the fluorescent pattern 12 represents a homothety by enlargement of the outline 26 of the color pattern 24, and the center of the fluorescent pattern 12 is superimposed on the center of the color pattern 24. This latter arrangement has the advantage of creating a halo effect of brightness around the color pattern 24.

[0047] The identity document 10 may comprise other layers on the side opposite the white substrate. According to a particular embodiment, the identity document 10 further comprises a third 34 and fourth 36 transparent substrates assembled on the side opposite the first and second substrates. It is thus possible to form an identity document 10 symmetrical in its thickness and to add on each side of the document color images illuminated by a fluorescent ink when it is under UV radiation.

[0048] The identity document 10 described above finds its use in a verification method which will make it possible to verify the authenticity or integrity of the identity document 10.

[0049] The verification method comprises the following steps. In a first step, the identity document 10 is exposed to ultraviolet radiation emitted by an external light source. In a second step, a reading device or a user will read the identity document 10 by a machine or by a user will read the readable data on the document and more particularly the color image generated by the matrix and the blackened areas, this color image being highlighted and lightened by the fluorescent radiation of the fluorescent pattern 12. A third step of the method consists of comparing the color image obtained with another piece of data from the identity document 10.

[0050] By way of example, the personalized color pattern 24bis represents the face of the holder of the document. This pattern is obtained from a photographed image of the holder, this image then being broken down into color pixels 28. Image processing software associates each color pixel with a contribution value of the sub-pixels 28a, 28b, 28c forming the matrix. These sub-pixels are for example black, yellow and magenta in color. This contribution value will make it possible to identify which sub-pixels 28a, 28b, 28c must be extinguished by blackening 30 of the first substrate 16 and which sub-pixels 28a, 28b, 28c must contribute to the generation of the personalized color pattern 24bis. Then, the selective blackening step 30 is carried out as described above, to generate the personalized color pattern 24bis.

[0051] This generated 24bis personalized color pattern forms a small secondary portrait, the brightness and color intensity of which is improved under ultraviolet lighting thanks to the arrangement of the document according to the invention.

[0052] The identity document 10 also includes a main portrait of the identity holder. It is then possible to compare, during a third step of the verification method, the personalized color pattern 24 read with the main image of the identity document 10. If the personalized color pattern 24bis and the main image represent the same face, the document is then considered valid.

Claims

Claims

1. Identity document (10) formed by assembling at least three substrates, each having the same surface, the substrates being laminated together, the three substrates being constituted respectively by an opaque white substrate, a first transparent substrate (16) and a second transparent substrate (18), the second substrate (18) being sandwiched between the opaque white substrate (20) and the first substrate (16), the first and second substrates (16, 18) being constituted by polymer materials, with a thickness of between 50 pm and 300 pm, the document comprising a color pattern (24) with a surface area smaller than that of the substrates, the color pattern (24) being delimited by a color contour (26) and being positioned at the interface of the two transparent substrates (16, 18), the color pattern (24) being formed by a matrix of sub-pixels (28a, 28b, 28c) each having a color different, and the first and / or the second substrate (16,18) transparent being sensitive to IR laser radiation (YAG), and the first substrate (16) comprising selectively blackened areas above the sub-pixel matrix (28a, 28b, 28c) so as to extinguish certain color sub-pixels so as to generate a personalized color pattern the second transparent substrate (18) forms a diffusion layer and in that the document further comprises a fluorescent pattern (12) produced by printing a fluorescent ink sensitive to Ultra-Violet radiation, the fluorescent pattern (12) being deposited at the interface of the first and second substrates (16, 18), under the color printing pattern, and the fluorescent pattern (12) having a fluorescent contour (22) of which at least a portion extends beyond the contour (26) of the color pattern (24).,

2. Identity document (10) according to claim 1, in which the contour (22) of the fluorescent pattern (12) represents a homothety by enlargement of the contour (26) of the color pattern (24).

3. An identity document (10) according to any preceding claim, wherein the UV-sensitive ink is a fluorescent white ink.

4. Identity document (10) according to one of the preceding claims, further comprising a third and fourth transparent substrate assembled on the side opposite the first and second substrate.

5. Identity document (10) according to one of the preceding claims, in which the opaque substrate (20) is opaque under ambient lighting in the visible and ultraviolet wavelengths.

6. Method for verifying an identity document (10) according to one of the preceding claims, comprising a first step of exposing the identity document (10) to ultraviolet radiation, then a second step of reading the personalized color pattern (24bis), and a third step of comparing the color pattern (24) with another data item of the identity document (10)

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