EP3548298A1

EP3548298A1 - Two security features that together form a third security feature

Info

Publication number: EP3548298A1
Application number: EP17808469.5A
Authority: EP
Inventors: Frédéric Beauchet; Michel Blanc
Original assignee: Banque de France
Current assignee: Banque de France
Priority date: 2016-12-02
Filing date: 2017-12-04
Publication date: 2019-10-09
Anticipated expiration: 2037-12-04
Also published as: FR3059594B1; CA3045099A1; MY195594A; MX2019006335A; AU2017367204A1; EP3548298B1; WO2018100203A1; FR3059594A1; PL3548298T3; CA3045099C; AU2017367204B2

Abstract

The invention concerns a set of N security features (105, 106, 110), each security feature forming, alone, an authentication feature different to those formed by the other security features, the different security features being shaped such that, when the N security features are superimposed, they together form an N+1th authentication feature (112) unrelated to the N other authentication features (107, 108, 111) each formed respectively by one of the N security features.

Description

TWO SECURITY SIGNS FORMING JOINTLY ONE

THIRD SECURITY SIGN

The invention relates to a set of at least two safety signs. The invention relates in particular, although not exclusively, to a set of two security signs to protect a security document such as a banknote or an identity document or a bank card.

BACKGROUND OF THE INVENTION In the field of security documents, and in particular banknotes, it is known to secure the document with the aid of one or more security signs.

It is thus common to equip a bank note with a security sign in two parts, a first part being inserted on the first face of the note and a second part being inserted on the second face of the note.

Thus when we look at the first face of the note in reflection (that is to say, by lighting the first side without illumination of the second face of the note) we observe the first part of the security sign. If we look at the second face of the note in reflection (that is to say by lighting the second side without illumination of the first face of the note), we observe the second part of the security sign. On the other hand if we study one of the faces of the ticket by transmission (that is to say with a main lighting of the unseen side and a secondary lighting of the studied side), the two parts of the security sign will be visible by superposition due to the low opacity of the note paper. It is thus possible to observe the security sign in its entirety.

Typically euro banknotes include such security features to form the digital value of the banknote. This type of security sign has the advantage of offering a good level of security since the two parts of the security sign must be properly placed on the two different faces of the bill so that they can be combined with each other. of security. In addition, this type of security sign is relatively simple to recognize by the general public who does not need special equipment to detect a fraudulent ticket.

Unfortunately, with technological advances, more and more powerful machines are available on the market and diverted by counterfeiters to fraudulently reproduce tickets. Even if these machines do not allow an identical reproduction of this type of security sign, they still allow a more than correct reproduction that can deceive many people of the general public.

OBJECT OF THE INVENTION

An object of the invention is to provide a set of security signs further complicating fraudulent reproduction of these security signs.

BRIEF DESCRIPTION OF THE INVENTION To this end, the invention proposes a set of N security signs, N being at least two, each security sign forming only an authentication mark different from those formed by the other signs of security. security, the various security signs being designed to form jointly N superimposed security signs, an N + l - th authentication mark unrelated to the other N authentication marks each formed respectively by one of the N signs of security.

In this way, not only the signs each form an authentication mark but the simple superimposition of the different signs forms another mark. additional authentication that is difficult to reproduce since it bears no relation to the other authentication marks and can not be linked to any security sign taken in isolation.

In particular, the N + 1 - th authentication mark is different from a simple combination of the other authentication marks such as a juxtaposition, a filling, a complement of the other authentication marks between them.

In this way, with N signs of security we manage to recreate at least N + 1 authentication marks which makes the whole very safe.

It is thus noted that the N + 1-th authentication mark exists only by the superposition of the various security signs and is therefore not related to any tangible element which makes it all the more difficult to reproduce.

Advantageously, it is also relatively simple for the general public to detect a counterfeit since it is sufficient to superimpose the security signs (for example by looking through transmission security assembly or by putting together the security signs ) to ensure the existence of the N + l-th authentication mark attesting the validity of the set.

In particular, the set comprises at least two security signs, a first security sign forming only a first authentication mark and a second security sign forming only a second authentication mark, different from the first mark of security. authentication, the two security signs being conformed to form jointly by superimposing at least the two security signs, a third authentication mark unrelated to the first authentication mark and the second authentication mark. In particular, each authentication mark forms only a locatable image having a full meaning.

The authentication mark can thus be an alphanumeric sign, a drawing, a geometrical figure, a bar code ...

In particular, at least two security signs are carried by the same object.

In particular, at least one of the security signs is arranged on the first main face of the object and at least one of the other security signs is arranged on the second main face of the object, the two signs being arranged in the same portion of the object.

In particular, at least two of the security signs are arranged on the same main face of the object, a folding of the object allowing a superposition of the two security signs.

In particular, N is at least three. In particular, the at least three security signs are printed using inks having at least one absorption / excitation wavelength common to the three security signs, the third sign being further in an ink exhibiting at least one absorption / excitation wavelength of its own and to which the other two safety signs do not react.

In particular, at least one of the security signs is displayed on a device with a screen and at least one other security element is carried by an object.

In particular, at least one of the security signs carried by the object is in an ink different from those of the rest of the object.

In particular, at least one of the security signs is in an ink visible in the light of day. In particular, at least one first security sign is printed using an ink comprising a first absorption / excitation wavelength and a second absorption / excitation wavelength, and at least one second security sign is printed on the at least one first security sign in an ink comprising the first absorption / excitation wavelength and a third absorption / excitation wavelength different from the second wavelength absorption / excitation.

In particular, the at least one first security sign and the at least one second security sign are printed with inks reissuing different colors so that the N + 1-th authentication mark appears in a panel color scheme comprising a color resulting from the combination of said colors of the at least one first security sign and the at least one second security sign.

Other features and advantages of the invention will emerge on reading the following description of particular non-limiting embodiments of the invention.

DESCRIPTION OF THE FIGURES

The invention will be better understood in the light of the description which follows with reference to the figures of the appended drawings among which:

FIG. 1 is a very schematic sectional view of a document comprising an assembly according to a first embodiment of the invention,

FIG. 2 is a view from above of the document illustrated in FIG. 1 and studied by reflection,

FIG. 3 is a view from below of the document illustrated in FIG. 1 and studied by reflection, FIG. 4 is a view from above or from below of the document illustrated in FIG. 1 and studied by transmission,

FIG. 5 is a very schematic sectional view of a document comprising an assembly according to a second embodiment of the invention as well as a representation of the various security signs studied in reflection and in transmission,

FIG. 6 is a very schematic sectional view of a document comprising an assembly according to a third embodiment of the invention as well as a representation of the various security signs studied in reflection and in transmission,

FIG. 7 is a very diagrammatic view from above of a document comprising an assembly according to a fourth embodiment of the invention before and after folding of the document,

FIG. 8 is a very diagrammatic view of a document and a device provided with a screen comprising an assembly according to a fifth embodiment of the invention,

FIGS. 9a to 9c are very schematic views from above of an object comprising an assembly according to a sixth embodiment of the invention according to different lighting of the object.

DETAILED DESCRIPTION OF EMBODIMENTS OF

THE INVENTION

With reference to FIGS. 1 to 4, according to a first embodiment of the invention, a document 1, such as a security document (banknote, identity card, passport, bank card, etc.) or a document another type of document (lottery ticket ...) comprises a support 2 carrying a security assembly according to the first embodiment of the invention. In the present embodiment, the same document 1 carries the security assembly and thus here two security signs.

In particular, the support 2 is shaped so that a first main face 3 of the support 2 carries the first safety sign 5 and so that the second main face 4, opposite the first main face 3, bears the second sign 6. The two security signs 5, 6 are here arranged to be located in the same area of the support 2. Thus, the two security signs 5, 6 are naturally superimposed on each other (well only separated by the thickness of the support 2).

The support 2 is here shaped to allow both a study in reflection of the two main faces 3, 4 and at the same time a study in transmission of each of said faces. A support 2 like that used in the banknotes is for example appropriate. The support 2 is for example paper or polymeric material.

Preferably, at the area of the support 2 carrying the two security signs 5, 6, the support 2 is adapted to be more transparent than in the rest of the support 2 to further improve the transmission study. Typically, a zone can be made more mechanically transparent by locally reducing the thickness of the support 2 (by a watermark technique, by calendering, etc.) or chemically by means of a varnish, a ink or solution at the time of forming the support 2 or once the support 2 created.

It is also possible to adapt the printing density of the inks to obtain a more transparent zone than in the rest of the support 2.

Moreover, the print density of the inks can be adapted so that one of the faces of the document 7 is darker than the other. In this way, this makes it possible to observe with identical or almost identical the least dark face, in reflection the sign carried by said face and in transmission the sign carried by the darkest face.

Here the security signs 5, 6 are here printed in other inks than those used for the rest of the support 2.

This makes it easier to observe the different authentication marks.

Typically, the security signs 5, 6 are printed in inks having a high contrast with those used for the rest of the support 2 to facilitate the study in reflection, said inks being otherwise relatively opaque to facilitate the study in transmission. Inks are here inks visible in the light of day.

Thus, as can be seen in FIG. 2, when one observes the first main face 3 in reflection, the first authentication mark 7 formed by the first security sign 5 is clearly visible. For example, the first authentication mark 7 includes a scientific formula (E = MC ² ) and a drawing (a flash).

If we observe the second main face 4 in reflection, as shown in Figure 3, the second authentication mark 8 formed by the second security sign 6 is also clearly visible. For example, the second authentication mark 8 has a word (Einstein).

However, if we observe one of the two main faces in transmission (for example by looking at the first main face 3), the two security signs 5, 6 are visible by superposition of one another.

Because of their superposition, the two security signs 5, 6 then draw a third authentication mark 9 unrelated to the first mark. Authentication 7 and the second authentication mark 8.

We thus note that with two security signs 5, 6 we manage to create three authentication marks. In addition, the third authentication mark 9 is particularly difficult to reproduce because it exists only by the superposition of the two security signs 5, 6 and can not be connected to any security sign 5, 6 taken isolation.

As can be seen in FIG. 4, the third authentication mark 9 is here a drawing (schematizing electrons gravitating around a nucleus).

There is thus a document 1 secured in an effective manner and the detection of a fraudulent reproduction is very simple by simple study by transmission.

In fact, the security package is based on the following general principle.

We create an image M (also called mask) randomly composed here of black and white pixels, thus having no meaning. We also create an image S (also called secret image) of the same size as the image M, also composed of black and white pixels, and representing something (a drawing, a geometric figure ...). Then we create an image C (also called encrypted image) using a logical operator "or exclusive" between the image M and the image S. The image C then has no meaning.

It then suffices to print the image C and the image M on different transparent sheets and then to superpose said sheets so that an unveiled image D, corresponding to the image S but with less contrast, appears at the level of the superposition of the images C and M. Indeed, the superposition of the images C and M amounts to making a logical operator "or" between the image C and the image M which thus makes it possible to display the image D.

In the present invention, however, it is always sought to have authentication marks that is to say images having a meaning.

For this purpose, the security assembly is here manufactured as follows.

We first choose the three images II, 12, 13 which will correspond to the final respectively to the first authentication mark 7, the second authentication mark 8 and the third authentication mark 9. Thus the three images I1 , 12, 13 each have a meaning but the three images II, 12, 13 have no relation to each other. The images I1, 12, 13 are all of identical size, each pixel of each image being either black or white. The images I1, 12, 13 thus have a high contrast and there is a 100% contrast between the black and white pixels of these images.

The images I1, 12, 13 are then processed in the following manner.

First, the first image II is broken down into a mask M1, each pixel of which in fact forms a matrix of size 2 * 2. In this way, the mask M1 is not the same size as the first image II.

For a white pixel of the first image II, a so-called white pixel is created in the mask M1, that is to say a pixel whose matrix comprises two white zones and two black zones. A so-called white pixel in the mask M1 is composed of 50% white areas. In order to create a mask, the distribution of the black and white areas in the pixel is performed randomly. A so-called white pixel in the mask M1 is therefore randomly chosen from the following possibilities:

In the same way, for a black pixel of the first image II, a so-called black pixel is created in the mask M1, ie a pixel comprising a white zone and three black zones. A pixel said black in the mask M1 is composed of 75% black areas. Similarly, the distribution of the black and white areas in the pixel is performed randomly. A black pixel in the mask M1 is therefore randomly selected from the following possibilities:

Thus a mask M1 is obtained, since it is randomly constructed at its pixels, which however forms the first authentication mark 7, that is to say an image that can be identified in itself, since the pixels of the matrix M1 are defined from image II. In fact, the mask M1 forming the first authentication mark 7 (ie the scientific formula E = MC ² and the flash) is identical to the image II but has just a lower contrast than the image II since the pixels Ml mask blanks are 50% white, and the black M M pixels are 75% black.

Then the second image 12 is broken down into an encrypted image C2, each pixel of which in fact forms a matrix of size 2 * 2. The second image 12 and the encrypted image C2 therefore do not have the same size.

In the same way as for the mask M1, a so-called white pixel in the encrypted image C2 is a pixel comprising two white zones and two black zones so that a so-called white pixel in the encrypted image C2 is composed at 50% white areas. As for a so-called black pixel in the encrypted image C2, it is a pixel comprising three zones black and a white area is a pixel composed of 75% black areas.

However, unlike the mask M1, the distribution of the black and white areas within each pixel of the encrypted image C2 is not chosen randomly.

Indeed, the encrypted image C2 must first correspond to the second image 12 to form the second authentication mark 8 (here the word Einstein). In this way, if a pixel is black in the second image 12, the corresponding pixel of the encrypted image C2 must also be a so-called black pixel and if a pixel is white in the second image 12, the corresponding pixel in the image encrypted C2 must also be a so-called white pixel.

Furthermore, the encrypted image C2 must also be shaped so that the superposition of the mask M1 and the encrypted image C2 forms the third authentication mark 9 linked to the third image 13.

The third authentication mark 9 corresponds here to the unveiled image D3. The unveiled image D3 is such that each pixel actually forms a matrix of size 2 * 2. The third image 13 {which corresponds to the secret image) and the unveiled image D3 therefore do not have the same size. On the other hand, a so-called white pixel in the unveiled image D3 is a pixel comprising a white zone and three black zones so that a so-called white pixel in the unveiled image D3 is composed of 75% black areas. As for a pixel said to be black in the unveiled image D3, it is a pixel comprising four black zones, ie a pixel composed of 100% black areas.

Moreover, it is recalled that the superposition of the mask M1 and the encrypted image C2 corresponds to the logical operator "or" that is to say that: for a superimposed black and white pixel of the mask M1 and the encrypted image C2 (or vice versa), the corresponding pixel of the unveiled image D3 will be black,

for two superimposed black pixels of the mask M1 and the encrypted image C2, the corresponding pixel of the unveiled image D3 will be black, and

for two superimposed white pixels of the mask M1 and the encrypted image C2, the corresponding pixel of the unveiled image D3 will be white.

The encrypted image C2 must therefore be constructed according to the following rules:

- 12 gives C2

13 gives D3

- C2 OR Ml = D3

For example, for a black pixel of 13, a white pixel of 12 and a white pixel of M1 (linked to II), there are six possible combinations (12, 13, M1) since M1 is randomly chosen and the pixels of 13 and 12 are respectively 100% and 100% black white (the dimensions of the ^pixels' shown is not met thereafter):

being reminded that a black pixel of 13 corresponds to a so-called black pixel of D3 composed of 100% black areas, we must have:

D3

and furthermore, since the pixel of 12 considered is white, the corresponding pixel of C2 must be called white so that necessarily C2 can be chosen only from the six possibilities below:

Therefore, in order to respect the above three rules, for each possible pixel shape of M1, there is only one possible pixel shape for C2 among the six possible so that the pixel of D3 is 100% black as indicated herein. above to know:

According to another example, for a black pixel of 13, a black pixel of 12 and a white pixel of M1 (linked to II), there are six possibilities of combination (12, 13, M1) since Ml is randomly chosen and the pixels of 13 and 12 are 100% black both (the dimensions of the pixels represented are not respected later):

Being reminded that a black pixel of 13 corresponds to a so-called black pixel of D3 composed of 100% black areas, one must also have:

On the other hand, since the pixel of 12 considered is black, the corresponding pixel of C2 must be said black so that necessarily C2 can be chosen only from the four possibilities below:

Therefore, in order to respect the three aforementioned rules, for each possible pixel shape of M1 there are only two possible pixel shapes for C2 among the four possible ones namely:

In this case, one selects randomly the shape of the pixel of C2 among the two possible ones.

For all the possible combinations (12, 13, M1), there is thus one or more possible pixel forms for C2 which makes it possible to respect the three rules mentioned above.

The encrypted image C2 which forms the second authentication mark, that is to say an image that is identifiable in itself, is thus constructed, since the pixels of the encrypted image C2 are defined from the image 12 In fact, the encrypted image C2 forming the second authentication mark is identical to the image 12 but just has a lower contrast than the image 12 since the so-called white pixels of the encrypted image C2 are formed at 50. % of white areas and so-called black pixels of the encrypted image C2 are formed at 75% of black areas.

In this way, it remains only to print the encrypted image C2 and the mask M1 on the respective faces of the support 2 to form respectively the first mark Authentication 7 and the second authentication mark 8.

In use, by superimposing the two brands ^r authentication 7, 8 (either the encrypted image and the mask Ml C2), that is to say, looking at the transmission, we obtain the unveiled picture S3. In fact, the unveiled image S3, which is also the third authentication mark 9, is identical to the image 13 but only has a less significant contrast than the image 13 since the white pixels of the unveiled image D3 are formed at 25% of white areas and the black pixels of the unveiled image D3 are formed at 100% black areas.

Note that the images represented in the various figures of the present application are diagrammatic since they do not represent (for questions of visibility) the less important contrast of the mask M1 and the encrypted image C2 vis-à-vis the initial images , or the less important contrast of the unveiled image S3 with the corresponding initial image on the one hand or with the mask M1 and the encrypted image C2 on the other hand.

With reference to FIG. 5, a second embodiment of the invention will now be described.

The second embodiment is here identical to the first embodiment, with the difference that the security assembly comprises a third security sign 110 arranged inside the support 102.

In particular, the support 102 is shaped so that the third security sign 110 is arranged in the same area of the support 102 as the other two security signs 105, 106. Thus, the three security signs 105, 106, 110 are naturally superimposed (but not contiguous by the thickness of the support). Alternatively, the signs are arranged so that at least two of the three signs are contiguous (for example by making two separate films each carrying a security sign and by subsequent joining of said films).

The third security sign 110 is here shaped to form a fourth authentication mark 111 in reflection (for example an apple) unrelated to the first authentication mark 107, the second authentication mark 108 and the third mark of authentication. authentication 109 which is formed by the superposition of the first security sign 105 and the second security sign 106 alone (respectively the E = MC ² formula plus flash, the set of electrons and the nucleus and a symbol "false" ). Thus, when one observes the first main face 103 in reflection, the first authentication mark 107 formed by the first security sign 105 is clearly visible.

If one observes the second main face 104 in reflection, the second authentication mark 108 formed by the second security sign 106 is also clearly visible.

On the other hand, if one observes one of the two main faces in transmission (for example by looking at the first main face 103), the three security signs

105, 106, 110 are visible by superposition. Because of their superposition, the three security signs 105, 106, 110 then draw a fifth authentication mark 112 (here a star) unrelated to the first authentication mark 107, the second authentication mark 108, the third authentication mark 109 and the fourth authentication mark 111.

It is thus noted that with three security signs 105,

106, 110 we manage to create five authentication marks. In addition, the fifth authentication mark 112 proves particularly difficult to reproduce since it exists only by the superposition of the three signs of security and can not be linked to any security sign taken in isolation.

In this embodiment, the mask / image encrypted / unveiled image principle is applied to the first authentication mark 107, to the second authentication mark 108 and to the fifth authentication mark 112 but via three safety signs 105, 106, 110.

Advantageously, if a person attempts to copy the document by scanner, it will scan both sides of the ticket and thus scan the authentication marks 107, 108 but without being able to scan the fourth authentication mark 111 which is inaccessible. In this way, once the fraudulent document has been created, when we look by transmission at the level of the reproduction of the authentication marks 107, 108, we will see the symbol "false" indicating that the ticket has been reproduced fraudulently.

Such a document 101 is therefore particularly well protected.

Optionally, the three security signs 105, 106, 110 are printed in inks having at least one absorption / excitation wavelength common to the three security signs. The third security sign 111 is also printed in inks also having at least one absorption / excitation wavelength different from those of the two other security signs.

For example, the three security signs 105, 106, 110 are all visible in daylight and the third security sign 110 is furthermore the only one to be visible in infrared light.

In this way, depending on the lighting, one can visualize in turn the different brands This makes the 101 document particularly secure.

Many variations are possible here.

The third authentication mark 109 may thus not exist. The superposition of the first authentication mark 107 and the second authentication mark 108 then gives no authentication mark (whether interpretable or not). However, this is not a problem for obtaining the fifth authentication mark 112.

Alternatively, the third security sign 110 is shaped so that the fourth authentication mark 111 is related to the third authentication mark 109 which is formed by the superposition of the first security sign 105 and the second security sign. 106.

With reference to FIG. 6, a third embodiment of the invention will now be described.

The third embodiment is here identical to the second embodiment, with the difference that the fourth authentication mark 213 is not interpretable without any figurative sign. On the other hand, the first security sign 205 and the second security sign 206 are also conformed so that the superposition of these only two security signs 205, 206 does not form a third interpretable authentication mark. As well as the third security sign 210, the superimposition of the first security sign 205 and the second security sign 206 thus form a third non-interpretable authentication mark 214 without any figurative sign (for questions of visibility the marks of authentication 213 and 214 are represented by a white square but are actually formed by a point cloud forming a more opaque area than is shown). On the other hand, the three security signs 205, 206, 210 are always shaped to form together by superposition a fifth authentication mark 212 unrelated to the first authentication mark 207, the second authentication mark 208, the fourth mark of authentication 213 and here the third authentication mark 214.

Thus, when one observes the first main face 203 in reflection, the first authentication mark 207 formed by the first security sign 205 is clearly visible (here the formula E = MC ^Z and lightning).

If one observes the second main face 204 in reflection, the second authentication mark 208 formed by the second security sign 206 is also clearly visible (here the electrons gravitating around the core).

On the other hand, if one of the two main transmission faces is observed (for example by looking at the first main face 203), the three security signs 205, 206, 210 are visible by superposition. Because of their superposition, the three security signs 205, 206, 210 then draw the fifth authentication mark 212 (here a star) unrelated to the first authentication mark 207, the second authentication mark 208, the fourth authentication mark 213 and also irrelevant here with the third authentication mark 214.

In this embodiment, the principle mask / image encrypted / unveiled image is applied to the first authentication mark 207, the second authentication mark 208 and the fifth authentication mark 212 but through three safety signs 205, 206, 210.

This makes the fraudulent reproduction of the document 201 even more complex. We note that with three security signs 205, 206, 210 we manage to create five authentication marks. In addition, the fifth authentication mark 212 is particularly difficult to reproduce since it exists only by the superposition of the three security signs 205, 206, 210 and can not be connected to any security sign 205, 206, 210 taken in isolation.

Alternatively, only the third security sign 210 or only the superposition of the first security sign 205 and the second security sign 206 will not form an interpretable authentication mark.

Alternatively, the third authentication mark 214 may not exist. The superposition of the first authentication mark 207 and the second authentication mark 208 then gives no authentication mark (whether interpretable or not). However, this is not a problem for obtaining the fifth authentication mark 212.

Referring to Figure 7, a fourth embodiment will now be described. This embodiment is identical to the first embodiment except that the second security sign 308 is arranged in a window 315 formed in the support 302 so that the second security sign 308 is visible on both sides of the support 302. by reflection. The window 315 is arranged in another area of the support 302 than the one where the first security sign 305 is located.

Thus, when we observe the first main face in reflection, the first authentication mark 307 formed by the first security sign 305 is clearly visible (here the sign @). Furthermore, the second authentication mark 308 formed by the second security sign 306 is also visible (here a gear). If we observe the second main face in reflection, the second authentication mark 308 formed by the second security sign 306 is also visible because of the window 315. The first authentication mark 307 is however not visible. by reflection.

If we now come to fold the support 302 so as to place the window 315 against the first security sign 305, the two security signs 305, 306 are then superimposed and we can then observe by reflection the third mark d 309 authentication (here the letter A).

Alternatively, one can also define the various security signs so that if the carrier 302 is folded this time to put the first security sign 305 on the window 315, a fourth authentication mark other than the third authentication mark then be visible at the level of the superposition of the two security signs.

It is thus noted that with two security signs 305, 306 we manage to create at least three authentication marks. In addition, the third authentication mark 309 (and possibly the fourth authentication mark) is particularly difficult to reproduce since it only exists by superimposing the two security signs 305, 306 and can not be connected to any security sign 305, 306 taken alone.

In replacement or in complement, one can have a different number of security signs printed on the first face of the document 301 and on which one can come to overlay the security sign 306 carried by the window 315 to form other marks of authentication and / or we can have different windows each carrying a security sign to form other authentication marks when the window 315 is affixed to the first security sign 305 or other security signs formed on the first face of the document 301.

Referring to Figure 8, a fifth embodiment will now be described.

While in the other embodiments, the set of security signs was carried by the same document, in the fifth embodiment, the first security sign 405 is still carried by the document 401 but the second security sign 406 is displayed on the screen 417 of a device 416. The device 416 is here a mobile phone.

Thus, when we observe the first main face of the document 401 in reflection, the first authentication mark 407 formed by the first security sign 405 is clearly visible (here the sign €).

If we look at the screen 417, the second authentication mark 408 formed by the second security sign 406 is also visible (here a star).

If we now affix the document 401 against the screen 416 so as to superimpose the first security sign 405 and the second security sign 406, the two security signs 405, 406 are then superimposed and we can then observe the third authentication mark (not shown here).

Preferably, in order to simplify the work of the user, the apparatus 416 is part of an overlay device including a camera 421 connected to the apparatus 416 for measuring the relative position of the document 401 on the screen 417. From the data provided by the camera 421, the apparatus 416 automatically repositions the second security sign 406 to be arranged under the first security sign 405. Preferably, the camera 421 is integrated in the camera 416. The camera 421 is thus the camera of the mobile phone.

In order to facilitate the task of the camera 421, the device comprises a tracking system 418 of the position of the document 401 on the screen 417. The tracking system here comprises a plate 419 arranged on the apparatus 416. The plate 419 comprises for example snap means 416 device to be easily removable. The plate 419 is here arranged at the end of the camera 416 at the camera 421, the plate 419 extending substantially perpendicular to the apparatus 416.

The plate 419 further includes a mirror 420 arranged at the upper end of the plate 419 so as to overlie the camera 421. The mirror 420 is arranged so that the measurement field of the camera 421 (centered on a viewing direction A) passes through said mirror 420 and is further arranged to reflect the screen 417 of the apparatus 416 in the measurement field of the camera. In this way, the camera 421 can view the screen 417 via the mirror 420. From the images reflected on the mirror 420, the camera 421 transmits the corresponding images of the position of the document 401 on the screen 417 to the apparatus 416 which allows the apparatus 416 to determine the relative position of the first security sign 405 and to position the second security sign 406 accordingly.

The mirror 420 is here arranged to reflect the entire surface of the screen 417 in the measurement field of the camera.

Thus with two security signs 405, 406 we manage to create three authentication marks. In addition, the third authentication mark is particularly difficult to reproduce since it exists only by the superposition of the two security signs 405, 406 and can not be connected to any security sign 405, 406 taken in isolation.

With reference to FIGS. 9a to 9c, a sixth embodiment according to the invention will now be described. It has already been seen in the previous embodiments that the third authentication mark was detectable by superposition of the two security signs in many different ways, for example by study by transmission, by folding ... Any other means to reveal the third mark Authentication is possible within the scope of the present invention.

Thus in this sixth particular embodiment of the invention, the security assembly is shaped so that the different authentication marks are studied only by reflection and without folding of the object 501 carrying the security assembly.

For this purpose, the two security signs are directly printed on each other in inks having both at least one common absorption / excitation wavelength and at least one wavelength. absorption / excitation different from that of the other ink. In this way, the third authentication mark is revealed when all the two security signs are illuminated in the field of their common absorption / excitation wavelength.

For example, the first safety sign is printed using a visible ink in daylight and under infra-red excitation for a wavelength around 800 nanometers. The second security sign is printed using a visible ink in daylight and under infra-red excitation for a wavelength around 900 nanometers. The two signs are printed on each other either directly on the object 501 or on a element reported on the object 501. The two signs are found and arranged on the same area of the object 501.

With reference to FIG. 9b, if the object 501 is illuminated under an infrared illumination centered on the wavelength of 800 nanometers, only the first security sign will react so as to reveal the first authentication mark 507 ( here a cross surrounded by a circle) which is visible in reflection.

With reference to FIG. 9c, if the object 501 is illuminated under infrared illumination centered on the wavelength of 900 nanometers, only the second security sign will react so as to reveal the second authentication mark 508 ( here a star) which is visible in reflection.

Finally, with reference to FIG. 9a, if the object 501 is illuminated in the visible, the two security signs will react so as to show, by superposition of the two security signs, the third authentication mark 509 (here a heart) which is therefore also visible in reflection.

Thus, in this embodiment, depending on the illumination with which the object 501 in reflection is studied, the first authentication mark 507, the second authentication mark 508 or the third authentication mark 509 appear.

We thus note that with two security signs we manage to create three authentication marks. In addition, the third authentication mark 509 is particularly difficult to reproduce since it exists only by the superposition of the two security signs and can not be connected to any security sign alone.

As a variant, it is of course possible to use other types of inks and we will thus be able to work with example in visible / ultraviolet or visible / ultraviolet / infra-red.

The invention is not limited to what has just been described, but on the contrary covers any variant within the scope defined by the claims.

Although here the assembly according to the invention is carried by the same document or by a document and an apparatus provided with a screen, this is not limiting and the assembly according to the invention may be worn from any other way. For example, the assembly according to the invention may be worn in part or in whole by another object than a document such as for example a token or a coin. The assembly according to the invention may be carried in part by a first object and partly by another second object reported on the first to show at least a third authentication mark. For example, the second object is a polarizing filter.

In particular, although here the security signs are directly printed on the support carrying them, the security signs can be formed directly on a dedicated base then reported itself on the support.

For example, the base may be a wire carrying at least one of the security signs, the security sign being inserted on the base before or after the arrangement of the base on the support. One or more safety signs will then be arranged in the support instead of being on one of the main faces of the support as described. The safety sign will for example be inserted into the support at a window formed in the support so that the wire is accessible from both sides of the support. The wire will then be shaped to allow a study in reflection and / or a study in transmission of said wire. Typically the wire may be in a multilayer film with interferential effects such as that described in the patent application FR 3,011,508 of the present applicant. Alternatively, the base may be a patch, a film of film such as a polymer film ... bearing at least one of the security signs, the security sign being inserted on the base before or after the arrangement of the base on the support.

The base may cover or fill a hole formed in the support to form a window so that the security sign is then accessible on both sides of the support. The base will then preferably, although not exclusively, shaped to allow study in reflection and / or transmission of said sign.

Of course at least one of the security signs may be arranged in one way on the support and at least one other security signs may be arranged in another way on the support: it will thus be possible to have a security sign arranged on a wire and a security sign arranged on a patch.

Moreover, although here the inks used are inks visible in the light of day, the inks used may in addition or in replacement be inks visible under other wavelengths typically under infra-red or ultraviolet. It is preferable that the inks are visible in the light of day when it is desired that a lambda user can easily detect a counterfeit or otherwise that the inks are invisible in the light of day to complicate a fraudulent reproduction of all of security.

Inks may be invisible in daylight and visible under ultraviolet or infrared excitation. The inks may be visible in daylight and fluorescent under ultraviolet or infrared excitation. We can also use inks re-emitting different colors on a first side of the support and on the second side of the support: so when will superimpose two security signs, the third authentication mark will appear in a color panel comprising the first color of the first authentication mark, the second color of the second authentication mark and in a third color resulting from the combination of the two colors. two colors to further complicate a fraudulent reproduction of the whole of the invention.

Although here the security signs are printed, it will be possible to form the security signs in a different way on the support or a base attached to the support, for example by embossing, by metallization, by metallization, etc.

Obviously, different techniques can be combined to create the same security sign and / or to create two different security signs.

Although here the authenticity marks cited are figures, drawings, words, mathematical formulas ... the authentication marks may be different. At least one of the authentication marks may thus comprise an authentication code for the medium or the object carrying it, such as for example a one - dimensional bar code, a two - dimensional bar code, a serial number, a SealgnOture code. (Trademark) ... Preferably, at least the authentication mark unveiled by superimposing the various security signs will include such an authentication code.

Although here it was said that the security assembly was made from images decomposed in mask / image encrypted / unveiled image whose pixels were matrices 2 * 2, it is understood that said matrices may be of different size eg 2 * 3 or 3 * 2, especially although not exclusively to create different levels of contrast or to allow overlapping more safety signs. The dies may also have other shapes than square or rectangular matrices and be for example of circular or hexagonal shape to reinforce the difficulty of fraudulent reproduction.

Although here we speak of black and white for the different pixels, this is not limiting and may have matrices composing different images, masks ... composed of pixels of other colors.

Moreover, although here the authentication marks are visible and controllable to the naked eye, it may be otherwise. It will thus be possible to use ultraviolet or infrared illumination to study at least one authentication mark or a polarizing filter (linear or circular).

In the case where one of the security signs is carried by one object and the other security sign is displayed on a device equipped with a screen, the device with a screen may include and / or be associated with other sensors than a camera to estimate the position of the object on the screen. For example in the case where the screen is touch, it can be directly the touch screen sensors that will determine the relative position of the object on the screen.

The device may be different from a mobile phone. The device may for example be a computer, a touch pad and generally any equipment with a screen.

Although here the sensor is integrated in the device, the sensor may be external and remote from the device. The sensor will then be connected to the device wired (for example by USB cable) or non-wired (for example by Bluetooth).

It will be possible to dispense with a tracking system, for example by equipping the apparatus with one or more stops so that the user can position the object in a predetermined manner.

The tracking system may have a different number of mirrors. As a variant or in addition, the tracking system may comprise other optical elements such as a mirror such as one or more optical fibers, one or more lenses.

The screen may be used to enhance the contrast of the third authentication mark and / or the second security sign.

Although here the second security sign displayed on the screen is fixed, there may be alternatively a second security sign that is regularly changed on the screen so that with the same first security sign affixed to it, the third authentication mark also changes regularly (with each change of the second security sign). We will thus have an evolution, a movement of the third authentication mark.

The device may be used to authenticate an object, the detection of a counterfeit can then come directly from the device through the possible observation of the third authentication mark by the camera of the device or may be left to the discretion of the user who will visualize the effects produced.

Claims

1. Set of N security signs (5,6; 105,106,110; 205,206,210; 305,306; 405,406), each security sign forming only an authentication mark different from those formed by the other security signs, the various security signs being formed to form, by superposition of the N security signs, an N + 1 - th authentication mark (9; 112; 212; 309; 509) unrelated to the N other authentication marks each formed respectively by one N security signs.

2. The assembly of claim 1, wherein at least two security signs are carried by the same object {5,6; 105, 106, 110; 205, 206, 210; 305.306).

An assembly according to claim 2, wherein at least one of the security signs (5,6; 105,106; 205,206) is arranged on the first major face of the object and at least the other security sign is arranged on the second main face of the object, the two signs being arranged in the same portion of the object.

4. An assembly according to claim 2 or claim 3, wherein at least two of the security signs (305, 306) are arranged on the same main face of the object, a folding of the object allowing a superposition of the two signs. of security.

5. An assembly according to one of the preceding claims, wherein N is at least equal to three.

An assembly according to claim 5, wherein the at least three security signs are printed using inks having at least one absorption / excitation wavelength common to the three security signs, the third sign of security being further in an ink having at least one wavelength its own absorption / excitation and to which the other two safety signs do not react.

7. An assembly according to one of the preceding claims, wherein at least one of the security signs (406) is displayed on a device (416) provided with a screen (417) and at least one other security sign (405) is carried by an object (401).

8. Assembly according to one of the preceding claims, wherein at least one of the security signs carried by an object is in an ink different from those of the rest of the object.

9. An assembly according to one of the preceding claims, wherein at least one of the security signs (5,6; 105,106,110; 205,206,210; 305,306; 405) is in an ink visible at the day light.

10. Assembly according to one of the preceding claims, wherein at least a first security sign is printed using an ink having a first wavelength of absorption / excitation and a second wavelength of absorption / excitation, and at least a second safety sign is printed on the at least one first safety sign in an ink having the first absorption / excitation wavelength and a third absorption wavelength / different excitation of the second wavelength of absorption / excitation.

11. An assembly according to one of the preceding claims, wherein the at least one first safety sign and the at least one second security sign are printed with inks reissuing different colors so that the third mark of authentication appears in a color panel comprising a color resulting from the combination of said colors of the at least one first security sign and the at least one second security sign.