EA044693B1 - SECURITY MARKING, METHOD AND DEVICE FOR READING SECURITY MARKINGS, SECURITY DOCUMENT MARKED WITH SECURITY MARKINGS, AND METHOD AND SYSTEM FOR VERIFICATION OF SAID SECURITY DOCUMENT - Google Patents

Description

Field of technology to which the invention relates

The present invention relates to the field of magnetically induced layers, methods and devices for reading a magnetically induced layer, as well as methods and systems for verifying and authenticating documents containing magnetically induced layers, wherein said magnetically induced layer contains oriented magnetic or magnetizable particles pigment.

Prerequisites for creating the invention

It is known in the art to use paints, compositions, coatings or layers containing oriented magnetic or magnetizable pigment particles, in particular also optically variable magnetic or magnetizable pigment particles, to obtain security elements in the form of magnetically induced markings, for example in the field of security documents . Coatings or layers containing oriented magnetic or magnetizable pigment particles are disclosed, for example, in US 2570856, US 3676273, US 3791864, US 5630877 and US 5364689. Coatings or layers containing oriented magnetic color changing pigment particles that result in eye-catching optical effects used to protect security documents are disclosed in WO 2002/090002 A2 and WO 2005/002866 A1.

Magnetic or magnetizable pigment particles in printing inks or coatings allow the creation of magnetically induced layers, patterns and/or designs by applying an appropriate magnetic field to ensure local orientation of the magnetic or magnetizable pigment particles in the uncured coating, followed by hardening of the latter. As a result, a stationary magnetically induced layer, pattern or design is obtained. Materials and techniques for orienting magnetic or magnetizable pigment particles in coating compositions are disclosed in US 2,418,479; US 2570856; US 3791864, DE 2006848-A, US 3676273, US 5364689, US 6103361, EP 0406667 B1; US 2002/0160194; US 2004/70062297; US 2004/0009308; EP 0710508 A1; WO 2002/09002 A2; WO 2003/000801 A2; WO 2005/002866 A1; WO 2006/061301 A1; these documents are incorporated herein by reference. Thus, it is possible to obtain magnetically induced layers that are highly resistant to counterfeiting. The magnetically induced layers thus obtained create an angular reflection profile that is substantially asymmetric with respect to the normal to the substrate on which they are deposited. This is unusual and differs from the classical nature of specular or Lambertian reflection/scattering.

Security features, for example for security documents, can be broadly divided into hidden security features on the one hand and explicit security features on the other hand. The protection provided by covert features is based on the concept that such features are difficult to detect and typically require specialized equipment and knowledge to detect, while overt features are based on the concept of being easily detected by the naked human senses, e.g. the features may be visible and/or tactilely detectable and still be difficult to manufacture and/or copy. Magnetically induced layers are typically used as explicit (or layer 1) security features that must provide direct and unambiguous human authentication without any external device or tool. However, the effectiveness of explicit security features depends to a large extent on their easy recognition as security features, since most users, and especially those who have no prior knowledge of the security features of the document or object protected by them, will only then actually perform a security check based on on the specified protective feature, if they really know about their existence and nature.

Even though the security level of magnetically induced layers is high in terms of copy resistance, the average consumer could potentially be confused as to what exact effect should be observed for a particular explicit security feature on a given product. In particular, a specular reflection hologram (a low-security, low-cost security element) creating such a pattern or logo may lead to misinterpretation of authenticity by an untrained consumer, as it will also create an angularly dependent reflection pattern.

In recent years, many authentication methods have emerged using a portable (pocket) device, such as a smartphone. Most of these methods rely on the imaging capabilities of a smartphone camera to extract geometric or topological information at a resolution below that of the human eye, such as the method disclosed in WO 0225599 A1, or beyond the human ability to extract signals very close to noise, or interpret subtle variations in the colors or shapes of the printed pattern, as disclosed in WO 2013071960 A1. These methods have the advantage of extracting encoded information for identification, but on the downside, they require high-resolution printing and/or magnifying optics attached to the smartphone camera.

Other authentication methods have been developed that are applicable to low-quality printed features.

- 1 044693 resolution, which are based on colorimetric analysis of the security feature, as disclosed in US 2011190920, based on holograms, or a technology such as, for example, SICPASMART™, disclosed in WO 2015052318 A1, which analyzes the color changing properties of optically varying patterns , measured during augmented reality, accompanied by the azimuthal displacement of the smartphone around the figure. These methods rely on moving the smartphone camera relative to the tag, which is difficult to achieve. Moreover, they are dependent on external lighting and are therefore very sensitive to ambient lighting conditions (e.g. direct sunlight, dark environments or highly unbalanced lighting).

Other methods have been proposed for authenticating features having an angular dependence of reflection intensity, such as randomly oriented flakes, as disclosed in WO 2012/136902 A1 and US 20140224879, micromirror, diffraction features, such as holograms or embossed three-dimensional structures, as disclosed in documents WO 2015/193152 A1 or US 2016378061. They are based on two angular camera positions to take snapshots of two images, which are then analyzed.

There remains the challenge of controlling both the smartphone camera and the sample illumination to obtain reproducible measurements of the reflectance of the security feature. Smartphone cameras typically use automatic exposure and focus algorithms that are tailored to the typical use of the camera (such as landscape or portrait photography), but such algorithms are not tailored to image highly reflective markings with magnetically induced layers. Illumination of the security feature may be due to ambient indoor or outdoor lighting, which is typically unknown and difficult to control, and may prevent reliable detection of specific security features of magnetically induced layers, such as angular reflectance.

Accordingly, currently known smartphone-based authentication methods have several disadvantages, including the following: they require high-resolution printing of microstructures; and/or they rely on complex smartphone movements to reveal color, and/or they are not reliable due to the limited information available to accurately authenticate the exact angular relationship.

Therefore, it is desirable to offer the public, and perhaps also relevant inspectors, an improved, accurate and reliable technical solution that is resistant to ambient light distortion, does not rely on high-resolution printing or complicated smartphone movement, and avoids difficult to operate and unintuitive inclined or azimuthal position or complex rotational motion.

In particular, there is a need for an authentication method and apparatus that can uniquely distinguish a given magnetically induced layer from another layer, or from another overt security feature created using other methods, as well as from simulations based on other technology that attempt imitate or simulate the effect, but reproduces the security feature or topology of the logo and has some angular dependence of the reflection intensity.

It is well known to authorize a user's access to a given service (eg, a website) over a communications network (eg, Internet or local communications) to allow the user to carry out certain transactions (eg, financial transactions on the user's bank account). Typically, the user must verify his or her identity using a cryptographic key and/or password to submit a request to the authority managing access: only if the password and/or key are correct is full access to the service authorized. However, the level of trust in such access is quite low, since the password or key may be stolen, or the user may be registered (for example, on a website or its controlling authority) under a false identity. Thus, there is a need to increase the level of trust in personal access credentials.

On the other hand, it is well known to use secure government-issued identification documents (such as ID cards or passports) to confirm the owner's identity to a controlling agent (for example, at the front desk) and then to gain access to certain services (or to a building). In this case, the agent will monitor some of the security markings that are difficult to forge, provided in the owner's identification document, perhaps check the similarity of the owner's face with the biometric data and/or photograph of the individual, and then, i.e., when the agent has obtained a sufficient level of confidence in the identity specified owner, the specified agent allows the owner to carry out certain authorized transactions. For example, WO 2014/160582 A1 discloses a method that includes the steps of: creating an association on a mobile device between a government-issued user identification document and a payment method; receiving on the mobile device the presentation of the user's government-issued identification document to support the payment request; verifying whether the government-issued identification document presented is valid identification

- 2,044,693 users; and in response to confirmation of presentation of government-issued identification, making payment using the specified payment method. A government-issued identification document may contain printed text, magnetic media, and a barcode.

An authentication method applicable to protected documents is also known, which is disclosed in US 2007/170248 A1. Said authentication method involves the reader capturing an image of the cardholder's face. Facial recognition software processes the image to create a hash function. The same reader is used to decode the digital watermark and/or barcode. The digital watermark (and/or barcode) includes an associated facial recognition hash function. If the hashes match, the identity and the identity document are authenticated.

The purpose of the present invention is to eliminate the need for prior identity verification through an agent and to provide any user with direct access to online services provided by a private or public operator, while providing the operator with a high level of trust in the user's true identity (and therefore true transaction rights). ).

It is therefore an object of the present invention to provide a method for authenticating a magnetically induced layer used as an overt security feature printed on or affixed to a substrate (such as a label, product or document) using a portable device, preferably a smartphone, to overcome the disadvantages of the prior art. .

It is yet another object of the present invention to provide a portable device, preferably a smartphone, for authenticating a magnetically induced layer deposited on a substrate, which is easy to control, has good immunity to ambient light variability and is highly resistant to imitation and easily distinguishes other reflective marks with angular addiction.

It is yet another object of the present invention to provide a method and system for both verifying the contents of a document and authenticating said document marked with a magnetically induced layer according to the present invention.

It is yet another object of the present invention to provide a suitable non-transitory computer readable medium containing portions of computer code or instructions executable by a processor to enable a portable device equipped with a light source and an image sensor to perform the sensing, decoding and authentication methods as described herein.

Brief description of the invention

According to one aspect, the present invention relates to a security marking (100) comprising a flat substrate (110);

a magnetically induced layer (120) of material containing magnetically oriented reflective plate-like magnetic or magnetizable pigment particles, wherein the magnetically induced layer (120) is deposited on a substrate (110) and contains a first zone (120a), wherein the flat edges of said magnetically oriented reflective lamellar magnetic or magnetizable pigment particles oriented in a first direction, and a second zone (120b) different from the first zone (120a), wherein the flat faces of said magnetically oriented reflective lamellar magnetic or magnetizable pigment particles are oriented in a second direction different from the first direction , wherein the plate-like particles in the first zone (120a) have flat faces with an elevation angle γ1 relative to the substrate plane (110) and the plate-like particles in the second zone (120b) have flat faces with an elevation angle γ ₂ relative to the substrate plane (110), each acute angle flat edges relative to the plane of the substrate (110) is in the range from about 5 to about 25°;

a machine-readable marking (130) comprising a reference pattern (133) and a code pattern (134) representing encoded data, the machine-readable marking (130) being respectively applied either to the top edge (121) of the magnetically induced layer (120) or to a substrate (110) between said substrate and a rear edge (122) of the magnetically induced layer (120), with a first region (134a) of the code pattern (134) located in front of the first region (120a), and the remaining second region (134b) of the code pattern ( 134) is located in front of the second zone (120b).

In the above security marking (100):

a) said pigment particles may contain:

a magnetic metal selected from the group consisting of cobalt, iron, gadolinium and nickel; a magnetic alloy of iron, chromium, manganese, cobalt, nickel or a mixture of two or more of them; magnetic oxide of chromium, manganese, cobalt, iron, nickel or a mixture of two or more of them; or a mixture of two or more of them; or

- 3 044693

b) The code pattern may be any of a 1D barcode, a stacked 1D barcode, a 2D barcode, and a 3D barcode.

The first zone (120a) and the second zone (120b) of the magnetically induced layer (120) may belong to the same layer of material. Alternatively, the first zone (120a) and the second zone (120b) of the magnetically induced layer (120) may respectively belong to the first sublayer and the adjacent second sublayer forming the magnetically induced layer (120) (by adjacent is meant that the first and second sublayers may be in direct contact or can be separated).

In the above security marking (100), a machine-readable marking (130) may be applied to the top edge (121) of the magnetically induced layer (120) and encoded with dark characters, and a dark primer layer (140) may be applied to the substrate (110), and a rear face (122) of the magnetically induced layer (120) may be applied to the top face (141) of a dark primer layer (140).

According to another embodiment of the security marking (100), a machine-readable marking (130) may be applied to the top edge (121) of the magnetically induced layer (120) and encoded with light characters, and a dark undercoat layer (140), preferably a black undercoat, may be applied onto the substrate (110), and a back face (122) of the magnetically induced layer (120) may be applied to the top face (141) of the dark primer layer (140).

In the aforementioned security marking (110), a machine-readable marking (130) may be applied to the substrate (110) and encoded with dark characters.

According to another aspect, the present invention relates to a method for reading and decoding the above-mentioned security markings (100) using a portable device (200) equipped with a light source (201) configured to supply light, an image generator (202) and a processor equipped with a memory and configured to with the ability to carry out image processing and decoding operations, including the stages of placing a protective marking (100) within the field of view of the image former (202);

illuminating the security marking (100) with light supplied by the light source (201);

obtaining a first digital image of the security marking (100) by the image generator (202) at a first viewing angle Θ1 associated with the first elevation angle γ1, and storing the obtained first digital image in memory;

obtaining a second digital image of the security marking (100) by the image generator (202) at a second viewing angle θ ₂ associated with a second elevation angle γ ₂ , and storing the resulting second digital image in memory;

generating, by processing the image by a processor, a composite digital image of the code pattern (134) from the stored first digital image and the stored second digital image by aligning with respect to the reference pattern (133) detected in the first digital image and the second digital image, the first part of the code pattern (134 ) corresponding to the first code pattern region (134a) detected on the first digital image, and the second code pattern region (134b) corresponding to the second code pattern region (134b) detected on the second digital image, and storing the resulting composite digital image in a memory;

the processor reading and decoding a code pattern (134) from the stored composite digital image.

The present invention also relates to a portable device (200) for reading and decoding the above-mentioned security marking (100), comprising a light source (201) configured to supply light;

an image generator (202) and a processor equipped with a memory and configured to carry out the steps of the above-mentioned method of reading and decoding a security marking (100) on digital images of said security marking (100) obtained by the image generator (202).

An additional aspect of the present invention relates to a security document (150) issued by an authorized body to the user and containing: a security marking (100) according to the present invention applied to the security document (150), with data encoded in a code pattern (134) of the security marking (100 ) contain digital identification data corresponding to the user, and a digital signature of the specified digital identification data of the user, and the digital signature provided by the authorized body is obtained by signing the digital identification data of the user with a cryptographic key.

Another aspect of the present invention relates to a method for verifying the above-mentioned security document (150) of a user using the above-mentioned portable device (200), further equipped with a communication unit configured to send and receive data via a communication network (CN) to an authority server (S), connected to a database (DB) storing

- 4 044693 a cryptographic key and a corresponding decryption key, said method comprising the steps of placing a security marking (100) within the field of view of the image generator (202);

illuminating the security marking (100) of the protected document (150) with a light source (201);

obtaining a first digital image of the illuminated security marking (100) by the image generator (202) at a first viewing angle Θ1 associated with the first elevation angle γ1, and storing the obtained first digital image in a memory;

obtaining a second digital image of the illuminated security marking (100) by the image generator (202) at a second viewing angle θ ₂ associated with a second elevation angle γ ₂ , and storing the resulting second digital image in memory;

generating, by image processing by an image processor, a composite digital image of a code pattern (134) from a stored first digital image and a stored second digital image by aligning, with respect to a reference pattern (133) detected in the first digital image and the second digital image, a first part of the code pattern (134), corresponding to a first code pattern region (134a) detected on the first digital image, and a second code pattern region (134) corresponding to a second code pattern region (134b) detected on the second digital image;

reading and decoding the code pattern (134) from the composite digital image and extracting from the decoded code pattern data (134) the user identification data and the digital signature of the specified user identification data, using image processing and decoding operations of the processor, and storing the extracted user identification data and digital signatures in memory;

sending a first message (M1) containing the extracted user identification data and digital signature stored in memory by the communication unit to the server (S);

decrypting at the server (S) the extracted digital signature received in the first message (M1) from the portable device (200) using the decryption key stored in the database (DB), and checking the match of the extracted user identification data received in the first message ( M1), with the received extracted digital signature; and if a match, sending back to the portable device (200) a server message (SM) indicating successful verification of the user's identity.

In an embodiment, the above-mentioned method of verifying a security document (150) may include, before the step of sending back a server message (SM) to the portable device (200), the preliminary steps of:

illuminating the magnetically induced layer (120) with a light source (201) and obtaining a plurality of digital images of the illuminated magnetically induced layer (120) by an imager (202), the imager (202) being positioned for each other digital image at a corresponding different viewing angle θ relative to said magnetically induced layer (120), by moving the imager relative to the magnetically induced layer (120) parallel to the plane of the substrate (110);

for each acquired digital image, calculating by the processor, respectively, the corresponding intensity I of light reflected by the magnetically induced layer (120) and collected by the image former (202) at the corresponding viewing angle θ, and storing the calculated values of the reflected light intensity and the corresponding viewing angles to obtain the corresponding curve Ι(Θ) of the intensity of reflected light;

sending the communication unit a second message (M2) to the server (S) via the communication network (CN), containing the received reflected light intensity curve Ι(Θ);

comparison on the server (S) of the reflected light intensity curve Ι(Θ) received in the second message (M2) with the reference reflected light intensity curve I _re f(θ) for the specified magnetically induced layer (120) stored in the database (DB) ;

determining at the server (S) the authenticity of the magnetically induced layer (120) based on the result of the comparison, and, in the case of determining the magnetically induced layer (120) as genuine, sending back to the portable device (200) a server message (SM) about successful verification identification of the user together with an indication that the security mark (120) is genuine, and sending by the server (S) over the communication network (CN) a server authorization message (SAM) to the user's communication device containing access data allowing the user to access the service . The user's communication device may be a portable device (200).

According to an alternative embodiment, the above-mentioned method of verifying the protected document (150) may include, in the case of delivery by the server (S) of a server message (SM) about the successful verification of the user's identification data, the additional steps:

illuminating the magnetically induced layer (120) with a light source (201) and obtaining a plurality of digital images of the illuminated magnetically induced layer (120) by an image former (202), wherein the image former (202) is placed for each other digital image under the corresponding an excellent viewing angle θ relative to the specified magnetically induced layer (120), by moving the image former (202) relative to the magnetically induced layer (120) parallel to the plane of the substrate (110);

for each acquired digital image, calculating by the processor, respectively, the corresponding intensity I of light reflected by the magnetically induced layer (120) and collected by the imager (202) at the corresponding viewing angle θ, and determining using the calculated values of the reflected light intensity and the corresponding viewing angles the corresponding curve Ι(Θ) of the intensity of reflected light;

comparing, by the processor, the reflected light intensity curve Ι(Θ) with a reference reflected light intensity curve I _re f(θ) for said magnetically induced layer (120) stored in the memory;

determining the authenticity of the magnetically induced layer (120) based on the comparison result, and, in the case of determining the magnetically induced layer (120) as genuine, sending a message (M) about the authenticity of the protective layer to the server (S) by the communication unit via the communication network (CN). markings (100); and in the event that the server (S) receives a message (M) from a portable device about the authenticity of the security marking (100), the server (S) sends back via the communication network (CN) a server authorization message (SAM) to the user’s communication device containing access data , allowing the user to access the service. The user's communication device may be a portable device (200).

A further aspect of the present invention relates to a system for verifying a security document (150) according to the present invention issued by an authority to a user, the system comprising an authority server (S) connected to a database (DB) and configured to send and receive data over a network communications (CN);

a portable device (200) according to the present invention for reading and decoding a security marking (100) according to the present invention applied to a security document (150) containing a light source (201) configured to supply light;

image generator (202);

a communication unit configured to send and receive data via a communication network (CN) to a server (S); and a processor equipped with a memory and configured to perform image processing and decoding operations for carrying out the steps of the above-mentioned method of reading and decoding the security marking (100) on digital images of said security marking obtained by the image generator (202);

wherein the server (S) and the portable device (200) are additionally configured to carry out steps of a method for verifying a user's protected document (150) by illuminating the security marking (100) of the protected document (150) with a light source (201), wherein the security marking (100) is within the field of view of the image former (202);

obtaining a first digital image of the illuminated security marking (100) by the image generator (202) at a first viewing angle Θ1 associated with the first elevation angle γ1, and storing the obtained first digital image in a memory;

obtaining a second digital image of the illuminated security marking (100) by the image generator (202) at a second viewing angle θ ₂ associated with a second elevation angle γ ₂ , and storing the resulting second digital image in memory;

generating, by processing the image by a processor, a composite digital image of the code pattern (134) from the stored first digital image and the stored second digital image by aligning with respect to the reference pattern (133) detected in the first digital image and the second digital image, the first part of the code pattern (134 ), corresponding to the first region (134a) of the code pattern (134) detected in the first digital image, and the second region of the code pattern (134) corresponding to the second region (134b) of the code pattern (134) detected in the second digital image;

reading and decoding the pattern (134) from the composite digital image, and extracting from the decoded pattern data (134) the user identification data and the digital signature of said user identification data, by image processing and decoding operations of the processor, and storing the extracted user identification data and digital signature in memory;

sending a first message (M1) containing the extracted user identification data and digital signature stored in memory by the communication unit to the server (S);

decryption on the server (S) of the extracted digital signature received in the first message (M1)

- 6 044693 from the portable device (200), using the decryption key stored in the database (DB), and checking that the extracted user identification data received in the first message (M1) matches the received extracted digital signature; and if a match, sending back to the portable device (200) a server message (SM) indicating successful verification of the user's identity.

The first embodiment of the above-mentioned system for verifying a security document (150) according to the present invention issued by an authorized body to a user, wherein the server (S) is further configured to send data via a communication network (CN) to the user's communication device; and the server (S) and the portable device (200) are further configured to perform, before the step of sending back a server message (SM) to the portable device, the preliminary steps of:

illuminating the magnetically induced layer (120) with a light source and obtaining a plurality of digital images of the illuminated magnetically induced layer (120) by an imager (202), the imager (202) being positioned for each other digital image at a corresponding different viewing angle θ relative to the specified magnetically -induced layer (120), by moving the image former (202) relative to the magnetically induced layer (120) parallel to the plane of the substrate (110);

for each acquired digital image, calculating by the processor, respectively, the corresponding intensity I of light reflected by the magnetically induced layer (120) and collected by the image former (202) at the corresponding viewing angle θ, and storing the calculated values of the reflected light intensity and the corresponding viewing angles to obtain the corresponding curve Ι(Θ) of the intensity of reflected light;

sending the communication unit a second message (M2) to the server (S) via the communication network (CN), containing the received reflected light intensity curve Ι(Θ);

comparison on the server (S) of the reflected light intensity curve Ι(Θ) received in the second message (M2) with the reference reflected light intensity curve I _re f(θ) for the specified magnetically induced layer (120) stored in the database (DB) ;

determining on the server (S) the authenticity of the magnetically induced layer (120) based on the comparison result and in the case of determining the magnetically induced layer (120) as genuine, sending back to the portable device (200) a server message (SM) about the successful verification of identification data the user along with an indication that the security mark (100) is genuine, and the server (S) sending over the communication network (CN) a server authorization message (SAM) to the user's communication device containing access data allowing the user to access the service.

A second embodiment of the above-mentioned system for verifying a security document (150) according to the present invention issued by an authorized body to a user, wherein the server (S) is further configured to send data via a communication network (CN) to the user's communication device; and the server (S) and the portable device (200) are further configured to carry out the following steps, in the event of delivery by the server (S) of a server message (SM) about successful verification of the user's identification data:

illuminating the magnetically induced layer (120) with a light source and obtaining a plurality of digital images of the illuminated magnetically induced layer (120) by an imager (202), the imager (202) being positioned for each other digital image at a corresponding different viewing angle θ relative to the specified magnetically -induced layer (120), by moving the image former (202) relative to the magnetically induced layer (120) parallel to the plane of the substrate (110);

for each acquired digital image, calculating by the processor, respectively, the corresponding intensity I of light reflected by the magnetically induced layer (120) and collected by the imager (202) at the corresponding viewing angle θ, and determining using the calculated values of the reflected light intensity and the corresponding viewing angles the corresponding curve Ι(Θ) of the intensity of reflected light;

comparing, by the processor, the reflected light intensity curve Ι(Θ) with a reference reflected light intensity curve I _re f(θ) for said magnetically induced layer (120) stored in the memory;

determining the authenticity of the magnetically induced layer (120) based on the comparison result, and, in the case of determining the magnetically induced layer (120) as genuine, sending a message (M) about the authenticity of the protective layer to the server (S) by the communication unit via the communication network (CN). markings (100); and in the event that the server (S) receives a message (M) from a portable device (200) about the authenticity of the security marking (100), the server (S) sends back via the communication network (CN) a server authorization message (SAM) to a user communication device containing access data allowing the user to access the service.

The present invention will now be described more fully with reference to the accompanying drawings, in which like numerals represent like elements in the different figures and which illustrate, but are not limited to, the essential aspects and features of the present invention.

Brief description of the figures

In fig. 1 schematically illustrates a plate-like pigment particle using Cartesian axes (X, Y, Z) attached to a (substantially flat) face of the particle.

In fig. 2A is a schematic illustration of a magnetically induced layer (120) according to an embodiment of the present invention comprising two zones (120a, 120b) in which magnetically oriented reflective platelet magnetic or magnetizable pigment particles have different orientations relative to the plane of the back face (122) of the magnetically induced induced layer (120): the first area (120a) with reflective platelet pigment particles has a first elevation angle γ1 and the second area (120b) with reflective platelet pigment particles has a second elevation angle _γ2 .

In fig. 2B schematically illustrates the magnetically induced layer (120) of FIG. 1 in cross section containing magnetically oriented platelet magnetic or magnetizable pigment particles in a single layer of material deposited on a flat substrate (110). The magnetically induced layer (120) contains two distinct zones (120a, 120b) in one layer (120) in which the reflective pigment particles have different elevation angles γ1 and _γ2 .

In fig. 2C schematically illustrates cross sections of a magnetically induced layer (120) according to an embodiment of the present invention comprising magnetically oriented platelet magnetic or magnetizable pigment particles in two layers on a flat substrate (110). The magnetically induced layer (120) contains two zones, wherein the first zone (120a) is a first layer of material containing magnetically oriented reflective platelet magnetic or magnetizable pigment particles with a first elevation angle γ1, and the second zone (120b) is a second a layer of material containing magnetically oriented reflective plate-like magnetic or magnetizable pigment particles with a second elevation angle γ ₂ , wherein the first and second layers have adjacent edges.

In fig. 3 schematically illustrates a componentized security marking (100) in perspective according to an embodiment of the present invention, comprising a flat substrate (110), a magnetically induced layer (120) having two zones (120a) and (120b) with distinct orientations of their magnetically oriented reflective plate-like magnetic or magnetizable pigment particles, with a top edge (121) and a back edge (122), and a machine-readable marking (130), with a top edge (131) and a back edge (132), wherein said machine-readable marking (130) partially overlaps magnetically induced layer (120).

In fig. 4A schematically illustrates a cross-sectional view of a security marking (100) comprising a flat substrate (110), a magnetically induced layer (120) with two zones applied to the substrate, and a machine-readable marking (130) printed on a top edge (121) magnetically induced layer, with the machine-readable marking (130) partially overlapping the magnetically induced layer (120).

In fig. 4B schematically illustrates a cross-section of a security marking (100) comprising a flat substrate (110), a dark primer (140) with a top edge (141) and a back edge (142), a magnetically induced layer (120) with two zones applied to a substrate, and a machine-readable marking (130), wherein said dark primer has a back edge (142) applied to the top edge of the substrate (110), and a back edge (122) of the magnetically induced layer (120) is applied to the top edge (141) dark primer, and the machine-readable marking (130) partially covers the magnetically induced layer (120).

In fig. 4C schematically illustrates a cross-sectional view of a security marking (100) comprising a planar substrate (110), a magnetically induced layer (120), and a machine-readable marking (130), wherein the machine-readable marking (130) is printed on the top edge of the substrate (110), and a rear edge (122) of the magnetically induced layer (120) is applied to the upper edge (131) of the machine-readable marking (130), and the machine-readable marking (130) partially overlaps the magnetically induced layer (120).

In fig. 5A illustrates a top view of an example of a machine readable code (130) in the form of a small QR code with a reference pattern (133) for placing the code pattern (134) during decoding operations, and a first region above the first magnetically induced layer zone (120a) and a second region above the second zone (120b) of the magnetically induced layer (shown in Fig. 3).

In fig. 5B illustrates a top view of an example of a machine readable code (130) in the form of a large QR code with a reference pattern (133) for placing the code pattern (134) during decoding operations, and a first area above the first magnetically induced zone (120a). layer and a second region above the second magnetically induced layer zone (120b) (shown in FIG. 3).

In fig. 5C illustrates a top view of an example computer readable code (130) in the form of a DataMatrix with an L-shaped reference pattern (133) for positioning the code pattern (134) during decoding operations, and a first region (134a) above the first magnetically induced zone (120a) layer and a second region (134b) above the second magnetically induced layer region (120b) (shown in FIG. 2).

In fig. 6A-B illustrate a handheld device (200) capturing images of a security marking (100) comprising a magnetically induced layer (120) with two zones (120a) and (120b) at two different viewing angles Θ1 and _θ2 , while illuminating the first and the second zones (120a) and (120b) are shown as (210a) respectively (210b), and the reflected light from the first and second zones is shown as (220a) respectively (220b).

In fig. 7 is a schematic flow diagram illustrating a method (700) for extracting encoded data from the machine-readable marking (130) of FIG. 5A.

In fig. 8A-B illustrate flowcharts of position estimation of two methods (800a) and (800b) for reading and decoding the security marking (100) according to the present invention by an imager of a portable device.

In fig. 9 illustrates an example of a security document (150) according to the present invention, that is, a user identity card issued by an authorized body.

In fig. 10 illustrates the method for verifying a protected document according to FIG. 9 according to the present invention.

In fig. 11 illustrates a system for verifying a security document according to the method illustrated in FIG. 9.

In fig. 12A-B illustrate a method of producing a magnetically induced layer (120) on a substrate (110), said layer (120) comprising biaxially oriented reflective plate-like magnetic or magnetizable pigment particles.

In fig. 13 illustrates a method of producing a magnetically induced layer (120) on a substrate (110), said layer (120) comprising uniaxially oriented reflective plate-like magnetic or magnetizable pigment particles.

In fig. 14A-D show photographs of security markings (100) where magnetically induced layers (120) are produced using the method and apparatus shown in FIG. 12-13.

Detailed description

To interpret the meaning of the terms discussed in the description and set forth in the claims, the following definitions should be used.

As used herein, the term at least one is intended to mean one or more, such as one, or two, or three.

As used herein, the term approximately means that the specified amount or value may have a specific defined value or some other value adjacent to it. In general, the term approximate, which denotes a specific value, is intended to indicate a range within ±5% of the value. As one example, the phrase approximately 100 denotes a range of 100 ± 5, i.e., a range of 95 to 105. In general, when using the term approximately, it would be expected that similar results or effects according to the present invention could be obtained within a range of ±5 % of the specified value.

As used herein, the term and/or means that either all or only one of the elements of a specified group may be present. For example, A and/or B would mean only A or only B, or both A and B. In the case of only A, the term also covers the possibility of the absence of B, i.e. only A and not B.

The terms containing and including as used herein are non-exclusive and subject to change. Thus, for example, a mixture containing/including compound A may contain other compounds in addition to A. However, the terms containing and including also cover, as in their particular embodiment, the more restrictive meanings consisting essentially of and consisting of, so that, for example, a mixture containing A, B and optionally C may also (substantially) consist of A and B or (mostly) consist of A, B and C.

The security marking (100) described herein comprises a flat substrate (110), which is preferably selected from the group consisting of paper or other fibrous materials (including woven and non-woven fibrous materials), such as cellulose, materials containing paper; glasses, metals, ceramics, plastics and polymers, metallized plastics or polymers, composite materials and mixtures or combinations of two or more of them. Typical paper, paper-like or other fibrous materials are made from a variety of fibers, including, but not limited to, manila hemp, cotton fiber, flax fiber, wood pulp and mixtures thereof. However, according to another embodiment, the substrate (110) may be based on plastics and polymers, metallized plastics or polymers, composite materials and

- 9 044693 mixtures or combinations of two or more of them. Suitable examples of plastics and polymers include polyolefins such as polyethylene (PE) and polypropylene (PP), including biaxially oriented polypropylene (BOPP), polyamides, polyesters such as poly(ethylene terephthalate) (PET), poly(1,4- butylene terephthalate) (PBT), poly(ethylene-2,6-naphthoate) (PEN) and polyvinyl chloride (PVC). High velocity air ejection molded olefin fibers, such as those sold under the trade name Tyvek®, can also be used as the support. Typical examples of metallized plastics or polymers include plastics or polymer materials described above herein, on the surface of which metal is continuously or discontinuously located. Typical examples of metals include, but are not limited to, aluminum (Al), chromium (Cr), copper (Cu), gold (Au), silver (Ag), alloys thereof, and combinations of two or more of the foregoing metals. Metallization of the plastic or polymeric materials described herein above may be accomplished by an electrodeposition process, a high-vacuum coating process, or a sputtering process. Typical examples of composite materials include, but are not limited to, multilayer structures or laminates of paper and at least one plastic or polymeric material, such as those described herein above, as well as plastic and/or polymeric fibers embedded in a paper-like or fibrous material, such as described above in this document. Of course, the substrate may contain additional additives known to those skilled in the art, such as fillers, sizing agents, brighteners, processing aids, reinforcing agents or wet strength agents, etc.

According to an embodiment of the present invention, the security marking (100), for example, as illustrated in FIG. 2 comprises a magnetically induced layer (120) made of a material containing a plurality of the described magnetically oriented reflective plate-like magnetic or magnetizable pigment particles, said pigment particles being fixed or immobilized (fixed/immobilized) in position and orientation in the material.

As shown in FIG. 1 and unlike needle-shaped pigment particles, which can be considered as one-dimensional particles, platelet pigment particles are quasi two-dimensional particles due to the large aspect ratio of their sizes. A lamellar pigment particle can be viewed as a two-dimensional structure where the dimensions along the X and Y axes are substantially greater than the Z dimension (ie thickness). Flake-like pigment particles are also referred to in the art as flattened particles or flakes.

Oriented reflective platelet magnetic or magnetizable pigment particles, due to their flat shape, have anisotropic reflectivity. As used herein, the term anisotropic reflectivity means that the fraction of incident radiation at a first angle that is reflected by a particle in some direction of view (second angle) depends on the orientation of the particles, i.e., that a change in the orientation of the particle with respect to the first angle can lead to different amounts of reflection in the viewing direction. Preferably, the reflective platelet magnetic or magnetizable pigment particles described herein have anisotropic reflectivity with respect to incident electromagnetic radiation in parts or all of the wavelength range from about 400 nm to about 1000 nm (i.e., wavelengths in the range from visible to near-IR), more preferably from about 400 to about 700 nm (ie, in the visible range), such that a change in the orientation of a particle causes the particle to change its reflectance in a particular direction. Thus, even if the intrinsic reflectance per unit surface area (for example, per µm ² ) is the same over the entire surface of a plate-like particle, due to its shape, the reflectivity of the particle is anisotropic, since the apparent area of the particle depends on the direction from which it is viewed. As is known to one skilled in the art, the reflective platelet magnetic or magnetizable pigment particles described herein differ from conventional pigments in that the conventional pigment particles have the same color and reflectivity, regardless of particle orientation, whereas magnetic or magnetizable The pigment particles described herein have either reflectivity, color, or both, which depends on the orientation of the particles within the layer material. The plate-like pigment particles, initially randomly distributed within the layer of material, were oriented by applying a strong (uniform) magnetic field through the layer, and then fixed/immobilized in position by subsequent solidification of the layer material. The flat faces of the plate-like pigment particles are then preferably oriented in the (uniaxial) direction of the applied magnetic field according to a statistical distribution with a sharp peak (eg, like a Gaussian). The pigment particles are thus statistically oriented and have their flat faces with a corresponding elevation angle relative to the layer plane. The angle between two planes is, by definition, the angle between the vectors normal to the corresponding planes, as well as the angle between the two straight lines of the corresponding windows that are perpendicular to the (straight) line at the intersection of the two planes. In this case, a straight line along the flat face of the oriented pigment particle (essentially according to the statistical distribution) is aligned with the direction of orientation of the pigment

- 10 044693 pigment particles. The full width at half maximum (FWHM) of this statistical distribution allows one to estimate the corresponding standard deviation for the orientation of the planar faces relative to the direction of the magnetic field lines. Thus, the normal direction to the face of the (uniaxially) oriented lamellar pigment particle may have an angle of inclination about the uniaxial orientation direction, which in practice is less than 30°. To have better relative orientation of the faces of different pigment particles (i.e., to reduce the angle of inclination and thus have better relative parallelism of the faces), a second magnetic field is applied (before solidification), the lines of which are oriented in a second direction (for example, along the axis Y shown in Fig. 1): With this biaxial orientation of the pigment particle faces, the above standard deviation is greatly reduced and the pigment particle faces are (statistically) parallel to each other, but still oriented in a given direction corresponding to the elevation angle. In preferred embodiments of the present invention, a biaxial magnetically induced layer is used, in which the edges of the pigment particles in each zone of the magnetically induced layer are biaxially oriented.

Suitable examples of platelet magnetic or magnetizable pigment particles include, but are not limited to, pigment particles containing a magnetic metal selected from the group consisting of cobalt (Co), iron (Fe) and nickel (Ni); a magnetic alloy of iron, manganese, cobalt, nickel or a mixture of two or more of them; magnetic oxide of chromium, manganese, cobalt, iron, nickel or a mixture of two or more of them; or a mixture of two or more of them. The term magnetic in relation to metals, alloys and oxides refers to ferromagnetic or ferrimagnetic metals, alloys and oxides. Magnetic oxides of chromium, manganese, cobalt, iron, nickel, or mixtures of two or more of these may be pure or mixed oxides. Examples of magnetic oxides include, but are not limited to, iron oxides such as hematite (Fe ₂ O ₃ ), magnetite (Fe ₃ O ₄ ), chromium dioxide (CrO2), magnetic ferrites (MFe ₂ O ₄ ), magnetic spinels (MR2O4), magnetic hexaferrites (MFe ₁₂ O ₁₉ ), magnetic orthoferrites (RFeO ₃ ), magnetic garnets M ₃ R ₂ (AO ₄ ) ₃ , where M is a divalent metal, R is a trivalent metal, and A is a tetravalent metal.

Other examples of platelet, magnetic or magnetizable pigment particles include, but are not limited to, pigment particles comprising a magnetic layer M made of one or more magnetic metals such as cobalt (Co), iron (Fe) or nickel (Ni); as well as a magnetic alloy of iron, cobalt or nickel, wherein said magnetic or magnetizable pigment particles may be multilayer structures containing one or more additional layers. Preferably, the one or more additional layers are layers A independently made from one or more materials selected from the group consisting of metal fluorides such as magnesium fluoride (MgF ₂ ), silicon oxide (SiO), silicon dioxide (SiO ₂ ), titanium oxide (TiO ₂ ) and aluminum oxide (Al ₂ O ₃ ), more preferably silicon dioxide (SiO ₂ ); or layers B independently made from one or more materials selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective metals and reflective metal alloys, and more preferably selected from the group consisting of aluminum (Al) , chromium (Cr) and nickel (Ni), and even more preferably aluminum (Al); or a combination of one or more A layers, such as those described herein above, and one or more B layers, such as those described above herein. Typical examples of lamellar magnetic or magnetizable pigment particles that are multilayer structures described hereinabove include, but are not limited to, A/M multilayer structures, A/M/A multilayer structures, A/M/B multilayer structures, A/B multilayer structures /M/A, multilayer structures A/B/M/B, multilayer structures A/B/M/B/A, multilayer structures B/M, multilayer structures B/M/B, multilayer structures B/A/M/A , B/A/M/B multilayer structures, B/A/M/B/A/ multilayer structures, wherein the A layers, the magnetic layers M and the B layers are selected from those described above herein.

In one embodiment, at least a portion of the preferred lamellar, magnetic, or magnetizable particles are formed by lamellar optically variable magnetic or magnetizable pigment particles. Optically variable pigments refer to a pigment having a change in brightness or a combination of a change in brightness and a change in hue. In one embodiment, at least a portion of the platelet, magnetic, or magnetizable particles are formed by particles having a metallic color, more preferably a silver color or a gold color.

Preferably, the platelet, magnetic or magnetizable pigment particles are selected from the group consisting of magnetic thin film interference pigment particles, magnetic cholesteric liquid crystal pigment particles, interference coated pigment particles containing magnetic material, and mixtures of two or more of them.

Magnetic thin film interference pigment particles are known to those skilled in the art and are disclosed, for example, in US Pat. No. 4,838,648; WO 2002/073250 A2; EP 0686675 B1; WO 2003/000801 A2; US 6838166; WO 2007/131833 A1; EP 2402401 B1; WO 2019/103937 A1; WO 2020/006286 A1 and the documents referred to therein. Preferably, the magnetic thin film interference pigment particles are pigment particles having a five-layer Fabry-Perot structure, and/or pigment particles having a six-layer Fabry-Perot structure, and/or pigment particles having a seven-layer Fabry-Perot structure, and /or pigment particles having a multilayer structure combining one or more multilayer Fabry-Perot structures.

Preferred five-layer Fabry-Perot structures consist of absorber/dielectric/reflector/dielectric/absorber multilayer structures, wherein the reflector and/or absorber is also a magnetic layer, preferably the reflector and/or absorber is a magnetic layer containing nickel, iron and/or or cobalt, and/or a magnetic alloy containing nickel, iron and/or cobalt, and/or a magnetic oxide containing nickel (Ni), iron (Fe) and/or cobalt (Co).

Preferred six-layer Fabry-Perot structures consist of: absorber/dielectric/reflector/magnetic material/dielectric/absorber multilayer structures.

Preferred seven-layer Fabry-Perot structures consist of: absorber/dielectric/reflector/magnetic material/reflector/dielectric/absorber multilayer structures, such as those disclosed in US 4,838,648.

Preferred pigment particles having a multilayer structure combining one or more Fabry-Perot structures are those described in WO 2019/103937 A1 and consisting of combinations of at least two Fabry-Perot structures, wherein said two Fabry-Perot structures independently contain a reflective layer, a dielectric layer, and an absorbing layer, wherein each of the reflective and/or absorbent layer independently may comprise one or more magnetic materials, and/or wherein the magnetic layer is a laminated material between the two structures. WO 2020/006/286 A1 and EP 3587500 A1 disclose further preferred pigment particles having a multi-layer structure.

Preferably, the reflective layers described herein are independently made from one or more materials selected from the group consisting of metals and metal alloys, preferably selected from the group consisting of reflective metals and reflective metal alloys, more preferably selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), gold (Au), platinum (Pt), tin (Sn), titanium (Ti), palladium (Pd), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni) and alloys thereof, even more preferably selected from the group consisting of aluminum (Al), chromium (Cr), nickel (Ni) and alloys thereof, and even more preferably aluminum (Al). Preferably, the dielectric layers are independently made of one or more materials selected from the group consisting of metal fluorides such as magnesium fluoride (MgF2), aluminum fluoride ( _AlF3 ), cerium fluoride ( _CeF3 ), lanthanum fluoride ( _LaF3 ), sodium aluminum fluorides (for example, Na ₃ AlF ₆ ), neodymium fluoride (NdF ₃ ), samarium fluoride (SmF ₃ ), barium fluoride (BaF ₂ ), calcium fluoride (CaF ₂ ), lithium fluoride (LiF), as well as metal oxides, such as silicon oxide (SiO), silicon dioxide (SiO ₂ ), titanium oxide (TiO ₂ ), aluminum oxide (Al ₂ O ₃ ), more preferably selected from the group consisting of magnesium fluoride (MgF ₂ ) and silicon dioxide (SiO ₂ ) and even more preferably magnesium fluoride (MgF ₂ ). Preferably, the absorbent layers are independently made of one or more materials selected from the group consisting of aluminum (Al), silver (Ag), copper (Cu), palladium (Pd), platinum (Pt), titanium (Ti), vanadium ( V), iron (Fe), tin (Sn), tungsten (W), molybdenum (Mo), rhodium (Rh), niobium (Nb), chromium (Cr), nickel (Ni), oxides of these metals, sulfides of these metals , carbides of these metals, as well as alloys of these metals, more preferably selected from the group consisting of chromium (Cr), nickel (Ni), oxides of these metals and alloys of these metals, and even more preferably selected from the group consisting of chromium (Cr ), nickel (Ni) and alloys of these metals. Preferably, the magnetic layer contains nickel (Ni), iron (Fe) and/or cobalt (Co) and/or a magnetic alloy containing nickel (Ni), iron (Fe) and/or cobalt (Co); and/or a magnetic oxide containing nickel (Ni), iron (Fe) and/or cobalt (Co).

If the magnetic thin film interference pigment particles containing a seven-layer Fabry-Perot structure are preferred, it is particularly preferable that the magnetic thin film interference pigment particles contain a seven-layer Fabry-Perot absorber/dielectric/reflector/magnetic material/reflector/dielectric/absorber structure consisting of multilayer structure Cr/MgF ₂ /Al/Ni/Al/MgF ₂ /Cr.

The magnetic thin film interference pigment particles described herein may be multi-layer pigment particles that are considered safe for human health and the environment and are based on, for example, five-layer Fabry-Perot structures, six-layer Fabry-Perot structures and seven-layer Fabry-Perot structures. Feather, wherein said pigment particles contain one or more magnetic layers containing a magnetic alloy having an essentially nickel-free composition comprising from about 40 wt.% to about 90 wt.% iron, from about 10 wt.% to about 50 wt. % chromium and from about 0 wt.% to about 30 wt.% aluminum. Typical examples of multi-layer pigment particles that are considered safe for human health and the environment can be found in EP 2402401 B1, the contents of which are incorporated herein by reference in their entirety.

Suitable magnetic cholesteric liquid crystal pigment particles exhibiting

- 12 044693 optically variable characteristics include, but are not limited to, magnetic single-layer cholesteric liquid crystal pigment particles and magnetic multi-layer cholesteric liquid crystal pigment particles. Such pigment particles are disclosed, for example, in WO 2006/063926 A1, US 6582781 and US 6531221. WO 2006/063926 A1 discloses monolayers and pigment particles derived from them with increased gloss and color change properties, as well as additional special properties , such as magnetizability. The disclosed monolayers and pigment particles, which are obtained from them by grinding said monolayers, include three-dimensionally cross-linked cholesteric liquid crystal mixture and magnetic nanoparticles. US 6,582,781 and US 6,410,130 disclose lamellar cholesteric multilayer pigment particles that contain the sequence A1/B/A2, wherein A1 and A2 may be identical or different from each other and each contains at least one cholesteric layer and B is an intermediate layer that absorbs all or some of the light transmitted by layers A1 and A2 and provides magnetic properties to said intermediate layer. US 6,531,221 discloses lamellar cholesteric multilayer pigment particles that contain the sequence A/B and optionally C, where A and C are absorbent layers containing pigment particles imparting magnetic properties and B is a cholesteric layer.

Suitable interference coating pigment particles containing one or more magnetic materials include, but are not limited to, structures consisting of a support selected from the group consisting of a core coated with one or more layers, wherein at least one of the core or one or more layers has magnetic properties. For example, suitable interference coating pigment particles comprise a core made of a magnetic material such as those described above, wherein said core is coated with one or more layers made of one or more metal oxides, or they have a structure consisting of a core, made of synthetic or natural mica, layered silicates (for example, talc, kaolin and sericite), glasses (for example, borosilicates), silicon dioxides (SiO ₂ ), aluminum oxides (Al ₂ O ₃ ), titanium oxides (TiO ₂ ), graphites and mixtures of two or more of them. Moreover, one or more additional layers, such as coloring layers, may be present.

The d50 size of the platelet, magnetic, or magnetizable pigment particles described herein is preferably from about 2 μm to about 50 μm (as measured by direct optical granulometry).

The surface of the platelet magnetic or magnetizable pigment particles described herein may be treated to protect them from any damage that may occur in the coating composition and coating layer and/or to facilitate their incorporation into said coating composition and a coating layer; Typically, corrosion inhibitors and/or wetting agents can be used.

The magnetically induced layer (120) described herein is produced by a method comprising the steps of a) applying a coating composition containing reflective platelet magnetic or magnetizable pigment particles described herein; b) exposing the coating composition to the magnetic field of a magnetic field generating device to orient at least a portion of the reflective platelet magnetic or magnetizable pigment particles, and c) solidifying the coating composition to fix the reflective platelet magnetic or magnetizable pigment particles in their positions, and orientations.

Preferably, the coating composition described herein contains reflective platelet magnetic or magnetizable pigment particles described herein dispersed in a binder material, wherein said reflective platelet magnetic or magnetizable pigment particles are present in an amount of from about 2 wt.% to about 40 wt.%, more preferably from about 4 wt.% to about 30 wt.%, the weight percentage being calculated based on the total weight of the coating composition containing the binder material, reflective platelet magnetic or magnetizable pigment particles and other optional components of the composition for covering. The coating composition described herein may further contain one or more color components selected from the group consisting of organic pigment particles, inorganic pigment particles, as well as organic colorants and/or one or more additives. The latter include, without limitation, compounds and materials that are used to adjust the physical, rheological and chemical parameters of the coating composition, such as viscosity (for example, solvents, thickeners and surfactants), consistency (for example, anti-settling agents, fillers and plasticizers), foaming properties (e.g. antifoams), lubricating properties (waxes, oils), UV resistance (photostabilizers), adhesive properties, antistatic properties, storage stability (polymerization inhibitors), etc. Additives described in this document , may be present in the coating composition in amounts and forms known in the art, including so-called nanomaterials in which at least one of the additive sizes is in the range of 1-1000 nm.

- 13 044693

The application step a) described in the previous paragraph is carried out by means of a printing process, preferably selected from the group consisting of screen printing, rotary gravure printing and flexographic printing. These processes are well known to one skilled in the art and are described, for example, in Printing Technology, JM Adams and PA Dolin, Delmar Thomson Learning, ^5th edition, pages 293, 332 and 352. While a coating composition containing reflective plate magnetic or magnetizable pigment particles described herein are still wet or soft enough to allow said pigment particles therein to move and rotate (i.e., while the coating composition is in the first state), the coating composition is subjected to a magnetic field to achieving particle orientation. The step of magnetically aligning the reflective plate-like magnetic or magnetizable pigment particles involves the step of exposing the applied coating composition, while it is wet (i.e., still liquid and not very viscous), to a specific magnetic field generated by a magnetic field generating device, aligning the reflective lamellar magnetic or magnetizable pigment particles along magnetic field lines to form an orientation pattern.

Subsequently, partially or concurrently with application of the coating composition, the reflective platelet magnetic or magnetizable pigment particles are oriented by using an external magnetic field to orient them according to the desired orientation pattern. The orientation pattern thus obtained may be any pattern except a random orientation pattern and except a pattern in which the magnetic axis of the reflective plate-like magnetic or magnetizable pigment particles is oriented to be parallel or perpendicular to the layer (120).

Methods for producing the magnetically induced layer (120) described herein include, partly simultaneously with step b) or after step b), step c) hardening the coating composition to fix the partially reflective plate-like magnetic or magnetizable pigment particles in their positions. and orientations in the required pattern for the formation of a magnetically induced layer, with the transformation of the coating composition into the second state. By this fixation a hard coating or hard layer is formed. The term curing refers to processes involving drying or setting, reacting, curing, cross-linking or polymerizing binder components in an applied coating composition, including an optional cross-linking agent, an optional polymerization initiator, and optional additional additives such that a substantially solid material is formed. , which sticks to the surface. As mentioned herein, the curing step c) can be carried out using different means or processes, depending on the materials contained in the coating composition, which also contains reflective platelet magnetic or magnetizable pigment particles. The curing step can generally be any step in which the viscosity of the coating composition is increased such that a substantially solid material is formed that is adhered to the load-bearing surface. The solidification step may include a physical process based on evaporation of a volatile component, such as a solvent, and/or evaporation of water (ie, physical drying). In this case, you can use hot air, infrared radiation, or a combination of hot air and infrared radiation. Alternatively, the curing process may involve a chemical reaction such as curing, polymerizing or cross-linking of the binder and optional starter compounds and/or optional cross-linking compounds contained in the coating composition. Such chemical reaction may be initiated by heat or IR radiation as described above for physical curing processes, but may preferably involve chemical reaction initiation by radiation, including but not limited to ultraviolet-visible curing (hereinafter referred to herein). as UV-visible curing) and electron beam curing (electron beam curing), oxypolymerization (oxidative reticulation, typically caused by the combined action of oxygen and one or more catalysts, preferably selected from the group consisting of cobalt-containing catalysts, vanadium-containing catalysts, zirconium-containing catalysts, bismuth-containing catalysts and manganese-containing catalysts); cross-linking reactions or any combination thereof. Radiation curing is particularly preferred and UV/Vis curing is even more preferred as these technologies advantageously result in very fast curing processes and therefore significantly reduce the turnaround time for any document containing magnetically induced layers described in this document. Additionally, radiation curing has the advantage of providing an almost immediate increase in viscosity of the coating composition upon exposure to curing radiation, thereby minimizing any further particle movement. As a consequence, any loss of information after the magnetic orientation step can generally be avoided. Particularly preferred is radiation curing by photopolymerization under

- 14 044693 exposure to actinic light having a component with a wavelength in the UV and visible part of the electromagnetic spectrum. UV-visible curing equipment may include a continuous or pulsed laser (eg, GaN), a high power light-emitting diode (LED) lamp, or an arc lamp such as a medium-pressure mercury arc (MPMA), or a lamp with a discharge in metal vapors as a source of actinic radiation.

If a primer (140), preferably a dark primer and more preferably a black primer, is present between the substrate (110) and the magnetically induced layer (120), the step of applying and curing the primer composition is carried out before obtaining said magnetically induced layer (120). The primer composition described herein can be applied by a variety of coating processes, preferably selected from the group consisting of inkjet printing processes, offset printing processes, flexographic printing processes, gravure printing processes, screen printing processes, pad printing processes and roller coating.

The magnetically induced layers (120) described herein comprise (at least) two zones (see FIG. 2A), with the first zone (120a) containing magnetically oriented reflective plate-like magnetic or magnetizable pigment particles having planar edges oriented in the first direction, and having a first elevation angle γ1 relative to the substrate (110), corresponding to the angle between said flat faces and the plane of the substrate (110), and a second zone (120b), different from the first zone (120a), contains magnetically oriented reflective plate-like magnetic or magnetizable pigment particles having flat edges oriented in a second direction different from the first direction, and having a second elevation angle γ ₂ relative to the substrate (110), corresponding to the angle between said flat edges and the plane of the substrate (110). To have a definition of elevation angles in two zones of the magnetically induced layer that is consistent with a general counterclockwise rotation direction corresponding to some given right-handed orthonormal triad defined on the reference plane (top face) of the substrate (for example, with the x and y axes lying in the plane, and the z axis oriented outward), the elevation angle γ1 of the flat face of the pigment particle in the first zone is the angle between the plane of the substrate and the plane of the face, measured counterclockwise, i.e. for positive rotation about the straight line L1 of the intersection of the flat face and the reference plane (from the reference plane to the flat face), while the elevation angle γ2 of the flat face of the pigment particle in the second zone is the angle between the substrate plane and the plane of the face, still measured counterclockwise , but this time for a positive rotation around a straight coincident line obtained by rotating in the reference plane the straight line L ₂ of the intersection of the flat face and the reference plane, aligning it with the line L1. This method of determining elevation angles in two distinct particle orientation zones allows for unambiguous comparison of elevation angles and orientation directions. In each zone of the magnetically induced layer (120), in accordance with experimental tests carried out in accordance with the present invention, the acute angles of the flat edges relative to the plane of the substrate (110) are preferably in the range of from about 5° to about 25°. In addition, as a result of these experimental tests, two distinct orientation directions of the flat edges in the two zones (120a) and (120b) are preferably located at an angle of at least 30° so as to have an acceptable contrast between the two zones when viewing the illuminated security marking (100) at two viewing angles, respectively, corresponding to the best reflection of light from the first zone and the second zone. In the example shown in FIG. 2, in which in each zone (120a, 120b) the edges of the pigment particles are substantially parallel to each other (i.e., the normals to the edges in each zone are substantially parallel, see Fig. 2A), the first elevation angle γ1, when measured in a counterclockwise direction, as defined above, has a value that is in the range from about 5° to about 25° (5°<γ1<25°), preferably from about 5° to about 20° (5°<γ1< 20°), and the second elevation angle γ ₂ , when measured in a counterclockwise direction as described above, has a value in the range from about 155° to about 175° (155°<γ ₂ <175°), more preferably from about 160° to approximately 175° (160° <γ ₂ <175°). Thus, the acute angle formed by the edges of the pigment particles in the second zone (120b) of the induced magnetic layer (120), i.e. the angle complementary to the elevation angle γ ₂ is thus in the range from about 5° (as 180°-175°=5°) to about 25° (as 180°-155°=25°).

In the embodiment shown in FIG. 2B, the magnetically induced layer (120) contains magnetically oriented platelet-like magnetic or magnetizable pigment particles in a single layer of material deposited on a flat substrate (110). In the embodiment shown in FIG. 2C, the magnetically induced layer (120) contains two distinct sublayers, respectively forming two zones (120a) and (120b), wherein the first sublayer and the second sublayer are adjacent, i.e. have adjacent edges that form a common boundary. According to another embodiment (not shown in FIG. 2C), two distinct sublayers, respectively forming two zones (120a) and (120b), are spaced apart from each other.

Instead of using a magnetically induced layer containing magnetically oriented reflective plate-like magnetic or magnetizable pigment particles with the elevation angles described herein, a diffractive, reflective, refractive microstructure, such as, for example, a diffraction grating, can be used, as well as layers containing a microlens or a micromirror structure, wherein said structure comprises micromirrors whose edges have certain elevation angles described herein.

According to the present invention, as illustrated in FIG. 3-5, a machine-readable marking (130), in the form of a two-dimensional bar code, including a reference pattern (133) and a code pattern (134) representing encoded data, is applied either to the top edge (121) of the magnetically induced layer (120) or to a substrate (110) between said substrate (110) and a rear edge (122) of the magnetically induced layer (120), with a first code pattern region (134a) located in front of the first region (120a), and the remaining second code pattern region (134b) 134) is located in front of the second zone (120b). The reference pattern (133) is used to accurately position the code pattern (134) during the image processing operation of reading and decoding the machine-readable marking (130). In fig. 5B illustrates an embodiment with a QR code and its characteristic reference pattern (133) of three squares. In fig. 5C illustrates an embodiment of the DataMatrix code with its L-like reference pattern (133). Other machine-readable code formats (eg, dot matrix) can be used for the present invention with their reference patterns. It is also possible to use machine-readable markings, in which the reference pattern is marked separately from the code pattern in an area external to the magnetically induced layer (but still must be in the reader's field of view when reading the machine-readable markings).

The machine-readable markings (130) described herein can be produced by any suitable method, including printing processes (particularly inkjet printing), etching and ablation techniques (particularly laser etching or burning), embossing techniques, etc.

In fig. 3 is an exploded view of a security marking (100) according to an embodiment of the present invention comprising a flat substrate (110), a magnetically induced layer (120) having two zones (120a) and (120b) with distinct orientations of their magnetically oriented reflective platelet magnetic or magnetizable pigment particles , with a top edge (121) and a back edge (122), and a machine-readable marking (130) in the form of a QR code, with a top edge (131) and a back edge (132), wherein said machine-readable marking (130) partially overlaps magnetically -induced layer (120). Here, a machine-readable marking (130) is applied on top of a magnetically induced layer (120) deposited on a substrate (110). The first region (134a) of the code pattern (134) is located in front of the first zone (120a), and the second region (134b) of the code pattern (134) is located in front of the second zone (120b). The effect of the present invention is that it is necessary to obtain two distinct images of the machine-readable marking (130) from two distinct viewing angles in order to obtain the complete encoded data from the encoding pattern, the viewing angles respectively corresponding to the elevation angles and orientations of the pigment particles in the two zones (120a) and (120b). Indeed, due to the difference in light reflectance of the two zones (120a) and (120b) of the magnetically induced layer (120), when displayed at one viewing angle, only one part of the displayed code pattern can be reliably detected, i.e. part of the code pattern corresponding to the area of the code pattern, which is located in front of the magnetically induced layer zone, providing the best contrast (at the correct viewing angle, corresponding to the elevation angle of the pigment particle faces in the specified zone, since the elevation angle of the pigment particle faces sets the viewing angle at which the specular reflection light from the face is maximum for a given position of the light source). Thus, it is not possible to obtain the required contrast for detecting encoded data simultaneously, from the same viewing angle, for both regions (134a) and (134b) of the code pattern (134). To reliably detect complete encoded data, it is necessary to first obtain two images of the machine-readable marking (130) from two different viewing angles adapted to the respective elevation angles of the edges of the pigment particles in the first zone (120a) and the second zone (120b) of the magnetically induced layer (120) to obtain in each image only the corresponding part of the code pattern (130) that can be reliably detected, and secondly, to reconstruct the image of the complete code pattern from these two acquired images to reassemble the two detected parts of the code pattern. Reconstruction requires the use of a mapped reference pattern (133) to have a common reference position element in the two images to accurately reassemble the two detected parts and reconstruct the decoded image of the complete code pattern (130). In the event that such recovery is possible, this implicitly means that the mapping operations were performed in accordance with a very specific security marking structure, and thus the security marking (100) is most likely genuine: this is another advantage of the present invention.

- 16 044693

In fig. 4A-C illustrate various embodiments of the security marking (100) according to the present invention. In the example of FIG. 4A, which shows the security marking (100) in cross section, the magnetically induced layer (120) applied to the substrate (110), and the machine readable marking (130) applied to the top edge (121) of the magnetically induced (mono)layer (120 ), with the machine-readable marking (130) partially covering the magnetically induced layer (120).

In the example of FIG. 4B, which shows the security marking (100) in cross section, a dark primer (140) (preferably a black primer) is located between the substrate (110) and the magnetically induced layer (120): the back edge (142) of the dark primer (140) is applied to the top edge of the substrate (110), and the back edge (122) of the magnetically induced layer (120) is applied to the top edge (141) of the dark primer, with machine-readable markings (130), possibly encoded with either light characters or dark characters, partially overlapping the magnetic induced layer (120).

In the example of FIG. 4C, which shows the security marking (100) in cross section, the machine readable marking (130) is applied to the top edge of the substrate (110), preferably encoded with dark characters, and the rear edge (122) of the magnetically induced layer (120) is applied to the top edge (131) machine-readable marking (130), wherein the machine-readable marking (130) partially overlaps the magnetically induced layer (120).

As explained above, in order to read and decode the two-zone magnetically induced layer (120), it is necessary to obtain (at least) two images of the security marking (100). According to the present invention, the method for reading and decoding security markings (100) uses a portable device (200), as illustrated in FIG. 6 (e.g., a smartphone), equipped with a light source (201) for supplying light, preferably in the visible or near-IR spectrum (i.e., for wavelengths from 400 nm to 1000 nm), an imager (202) for obtaining digital images (e.g. , smartphone camera) and a processor (not shown) equipped with a memory (not shown) and configured to perform image processing and decoding operations, the method comprising the steps of:

(i) illuminating the security marking (100) located within the field of view of the image former (202) with light supplied by the light source (201). For example, the light source is the LED (light emitting diode) flash of a smartphone, which is adjacent to the image sensor (smartphone camera);

(ii) obtaining a first digital image of the security marking (100) by the image generator (202) at a first viewing angle Θ1 associated with a first elevation angle γ1 of the pigment particles in the first zone (120a) of the magnetically induced layer (120), and storing the resulting first digital images in memory. In the above smartphone example, when the image sensor is positioned very close to the (quasi-point) light source, the viewing angle Θ1 at which the intensity of light reflected by the faces of the pigment particles in the first zone (120a) maximum corresponds to the position of the image sensor substantially in the direction normal to the edges of the pigment particles in the first zone (120a). At this viewing angle Θ1, only the part of the code pattern (134) that is applied to the first zone (120a) of the magnetically induced layer (120) can be reliably read (with good contrast) in the first digital image, while the part of the code pattern (134) that applied to the second zone (120b) of the magnetically induced layer (120), does not reflect a sufficient amount of light (Θ1 is not adapted to the elevation angle γ ₂ );

(iii) obtaining a second digital image of the security marking (100) by the imager (202) at a second viewing angle Θ2 associated with a second elevation angle γ2 of the pigment particles in the second zone (120b) of the magnetically induced layer (120), and storing the resulting second digital images in memory. In the above example of a smartphone, the image sensor of which is located very close to the (quasi-point) light source, the viewing angle Θ2 at which the intensity of the light reflected by the faces of the pigment particles in the second zone (120b) maximum corresponds to the position of the image sensor substantially in the direction normal to the edges of the pigment particles in the second zone (120b). At this viewing angle Θ2, only the part of the code pattern (134) that is applied to the second zone (120b) of the magnetically induced layer (120) can be reliably read (with good contrast) in the second digital image, while the part of the code pattern (134) which is applied to the first zone (120a) of the magnetically induced layer (120), does not reflect a sufficient amount of light (θ ₂ is not adapted to the elevation angle γ ₁ );

(iv) generating, by image processing by an image processor, a composite digital image (i.e., a reconstructed digital image) of a code pattern (134) from the stored first digital image and the stored second digital image by registration with respect to a reference pattern (133) (detected in the first digital image and second digital image) a first code pattern portion (134) corresponding to a first code pattern region (134a) detected in the first digital image, and a second code pattern portion (134) corresponding to a second code pattern region (134b) detected in the second digital image , And

- 17 044693 saving the resulting composite digital image in memory. In this case, the first part of the code pattern (134) is a part of the code pattern in the first region (134a), which is applied to the upper edge (121) of the first zone (120a) of the magnetically induced layer (120), and the second part of the code pattern (134 ) is a part of the code pattern in the second region (134b), which is applied to the upper edge (121) of the second zone (120b) of the magnetically induced layer (120);

(v) the processor reading and decoding the code pattern (134) from the stored composite digital image, i.e. from a reconstructed digital image of the complete code pattern, in which two regions of the code pattern can be simultaneously and reliably detected and decoded.

As explained above, the only way to reliably detect and decode the machine-readable marking (130) is to obtain two images, respectively, of the first region (134a) and the second region (134b) of the code pattern (134) from two viewing angles tailored to the specific orientations of magnetically oriented reflective plate-like magnetic or magnetizable pigment particles in the first zone (120a) and the second zone (120b) of the magnetically induced layer (120). The fact that the machine-readable marking of the security marking (100) can be decoded means that the structure of the magnetically induced layer (120) with two zones has been confirmed, and the viewing angles correspond to the correct elevation angles (i.e., the correct orientation) of the faces of the pigment particles in the two zones (120a) and (120b). Thus, the ability to decode the machine-readable marking (130) constitutes the first level of authentication of the security marking (100).

According to the present invention, an additional level of authentication of the security marking (100) can be achieved through greater use of the properties of the security marking material (100) itself. This can be done by acquiring multiple digital images of the security markings at different viewing angles θ _i (i=1,...,N) while moving the imager (202) of the portable device (200) over (and parallel to) the security markings (100) and forming from the obtained digital images and for each zone of the magnetically induced layer the corresponding curve I(θ _i ) (i=1,...,N) of the intensity I of light reflected from the specified zone at the specified different viewing angles, when illuminating the protective marking source (201) of light. Each Ι(Θ) curve allows a more detailed analysis of the reflectance (since intensity is a function of reflectance) of magnetically oriented reflective platelet magnetic or magnetizable pigment particles in the corresponding zone of the magnetically induced layer (120). In particular, the exact shape of the reflectance curve R(θ) ~ Ι(Θ) (R(θ) is the average reflectance), characterizing the nature and orientation of the pigment particles, as well as the material of the induced layer for the area under consideration, and showing the peak characteristic shape around The viewing angle values associated with the elevation angle of the pigment particles in this area can be compared with the reflectance reference curve R _re f(θ) ~ I _re f(θ) (known to the security marking authority) to decide whether the the shapes of two curves to a sufficient extent, based on the criterion of similarity of the curves. For example, curves can be compared using correlation. Another method is to perform linear regression to estimate the linear relationship between the measured and reference curve and estimate how close the slope gets to unity and how close to unity the goodness of fit gets. Preferably, each curve Ι(Θ) is obtained from the measured average intensities I of light reflected from the corresponding zone. This represents a strict verification of the authenticity of the structure of the security marking material and thus also verification of the authenticity of the encoded data in the machine-readable security marking. Another advantage of the present invention, which also facilitates the authentication of security markings, is the type of movement of the imager over the security marking that must be performed to properly obtain multiple digital images of the machine-readable markings according to the relative locations of the pigment particles in different zones of the magnetically induced layer. For example, in the case of the magnetically induced layer shown in FIG. 2, the orientation directions of the pigment particles in the first zone (120a) and the second zone (120b) are within a plane perpendicular to the plane of the substrate (110), the relative translational movement of the image former (202) and the security marking (100) (along the direction enclosed in limits of the specified perpendicular plane) is necessary to obtain multiple digital images to obtain the reflectance curve Ι(Θ). However, with a different design of two (or more) zones of orientation of the pigment particles of the magnetically induced layer (for example, with orientation directions at an angle of less than 180° or more than 180°), the relative movement will correspond to rotational movement. Preferably, the reflectance curve Ι(Θ) is obtained from the measured average intensities I. However, other metrics can be used to authenticate security markings. Additional embodiments may include authentication algorithms based on a neural network classifier or machine learning that are capable of distinguishing authentic intensity profiles (or other measured or extracted features such as dispersion profile or image entropy, etc.) from those that are are not authentic.

- 18 044693

As an example of an equivalent method for authenticating security markings, instead of measuring the (possibly averaged) light intensity reflected by the magnetically induced layer for a reflectance curve, machine learning can be applied to the above-mentioned set of digital images of security markings taken at different viewing angles θ _i ( i=1,...,N). This method includes the following three stages: feature extraction, model training and selection, and prediction.

As for the feature extraction stage, the imager returns a series of RGB images ^I( ^, where θ _min <θ<θ _mαx . If necessary, only the region of interest (RoI) around the security marking can be preserved by cropping the images. These images can be linearized and converted to scale gray (as described in R. C. Gonzalez, T. E. Woods, Digital Image Processing, fourth edition, Pearsons, 2017) However, separate processing of color channels is also possible.

For each image, one or more f(θ) metric functions are calculated. A detailed description of image metrics applied to images can be found in the above-mentioned book by R.C. Gonzales and T.E. Woods. Metrics can be calculated either directly from image intensity or from a transform such as the discrete Fourier transform (DFT) or discrete wavelet transform (DWT). Some useful metrics that can be used include mean, standard deviation, and entropy. Depending on the metric used, it may be necessary to scale it by the average intensity of the reference adjacent RoI (this operation compensates for variable imager exposure time and any changes in tag irradiation).

To ensure that all measurements have the same scale, metrics should be evaluated on a single angle sampling grid. These angles must be symmetrical relative to the normal to the sample. We can denote this uniform mesh as Θ=[Θ ₁ ,...Θ _ν ], where N represents the number of corners (for example, N=21). In practice, scanning at evenly spaced angles is not always possible and interpolation of metrics may be required. At the end of the scanning procedure, a feature vector x ^T = [f(θ ₁ )f(θ ₁ )...f(θ _N )]=[x ₁ x ₁ ...x _N ] is obtained. By further performing M scans on different security markings to account for their variability, a data set X ^T =[x1...xM] of size NxM is created.

Regarding the training and model selection phase, general machine learning methods for classification and detection are described in S. M. Bishop, Pattern Recognition and Machine Learning, Springer, 2009. In this case, the authentication problem comes down to distinguishing genuine feature vectors from fakes or attacks . However, while genuine feature vectors are known and available, others are either unknown or rare. Thus, direct training of a two-class classifier is not possible. As described in O. Mazhelis, One-Class Classifiers: A Review and Analysis of Suitability in the Context of Mobile Masquerader Detection, South African Computer Journal, col. 36, pp. 29-48, 2006, it can be shown that authentication is equivalent to one-class classification. In this scenario, classifier models rely only on ground truth feature vectors to learn their parameters and decision boundaries. Among them, support vector data description (SVDD), ν-Support Vector Classification (νSVC), Gaussian Mixture Models (GMM) and deep learning models are of practical interest. (deep-learning models), such as Autoencoders. The choice of model is dictated by its performance during training and is also limited by its complexity. For equivalent characteristics, simpler models are preferable.

Before training the model, the data set X is preprocessed as shown in the figure below and the following steps are carried out:

Sample cleaning:

Defective samples, such as those that are saturated or with missing features, are discarded. Normalization of samples.

Feature vectors are normalized to unit energy.

Standardization of features:

The mean value of the features μ(θ _d ) and the standard deviation of the features σ(θd ) are estimated and removed by feature.

Detrending samples:

Low-order polynomial trends of fixed order p are estimated for each sample and removed.

Reduced symptoms:

Correlations between features are removed, and the dimension of the problem is reduced. In this case, for example, the reduction can be from N=21 to K=3-5. Lower-dimensional optimization problems converge faster and make verification easier. This stage is carried out through principal component analysis (PCA) (see the book See Bishop, Pattern Recognition and Machine Learning, Springer, 2009), which creates a vector subspace V=[v1...v _K ], size NxK. After PCA, the data set X is projected onto the subspace V, which results in a reduced feature data set X' ^T = [x'1...x' _N ],

- 19 044693 size KxN. This data set is used to train the parameters Θ of possible one-class classification models. Finally, the best candidate remains for prediction.

As for the prediction stage, it performs data cleaning, sample normalization, feature standardization, detrending, subspace projection, and model decision function calculation based on the data set. Finally, after feature reduction, a classifier decision function with the learned parameters is computed using subspace projection (see also I. GoodFellow, Y. Bengio, A. Courville, Deep Learning, MIT Press, 2016).

In an exemplary embodiment of the above method based on a reflectance curve Ι(Θ) related to an example of a machine-readable QR code marking (130) (see FIGS. 3 and 5A), wherein overlapping the magnetically induced layer (120) and The machine-readable marking (130) is chosen to preserve the detectability of the code pattern (133) and the clock (thus the code pattern (134) can always be detected, although not necessarily decoded, from any viewing angle). A QR code is a well-known standardized symbology, graphically composed in such a way that the following three basic operations can be performed on the features or graphic elements derived from the QR code image:

1) Code layout using a specific graphical execution (reference figure (133)), which is reliably and accurately detected using suitable image processing algorithms.

2) Extracting the sampling grid and module size from a sequence of alternating dark and bright modules (the clocks are visible in Fig. 5A) arranged along one or more lines in two orthogonal directions.

3) Data, encoding mode and error correction area are contained in the QR code in other areas of FIG. 5A (on the right edge). Data is encoded as light and dark units in a specific area of the symbol according to a specific encoding algorithm.

The machine-readable code (130) of the security marking (100) is read and decoded by a portable device (200) comprising a light source (201) configured to supply light;

image generator (202) (camera), configured to obtain digital images of security markings (100); and a processor equipped with a memory and configured to implement the steps of the above method on digital images of the security markings (100) obtained by the image generator (202).

As illustrated in FIG. 7, by means of the decoding method (700) the first sequence of digital images of the security marking (100) is obtained (701) from different viewing angles of the image generator (202) relative to the security marking (100): the viewing angles are close to the first viewing angle Θ1 (which is associated with elevation angle γ1 of pigment particles in the first zone (120a) of the magnetically induced layer). The positions of the image sensor relative to the machine-readable markings (130) are estimated (702) using the acquired digital image sequence in a manner described below (in this context, the combination of position and orientation is referred to as object position in computer vision). The imager positions are checked against various acceptance criteria: for example, for 15°±3° relative to the normal to the substrate (110), it is checked whether the digital image from the sequence (703) is sharp enough. For example, checking Weber contrast, Michelson root mean square contrast. If the digital image in question is not received (703, H, i.e. no), the next digital image in the sequence is considered (701). If one position meets the acceptance criteria, the digital image corresponding to that position is processed further (703, D, i.e. Yes). This digital image is then corrected for perspective distortion and resampled using the specified resolution (704). Using imager position information and a priori knowledge of the location of the magnetically induced layer (120) in the security marking design, a mask can be constructed to preserve only that portion of the digital image where the first magnetically induced layer zone is currently located (705).

The same processing is repeated for the imager (202) at various viewing angles close to the second viewing angle θ ₂ (706-710). The second viewing angle θ ₂ is a viewing angle associated with the elevation angle γ ₂ of the pigment particles in the second zone (120b) of the magnetically induced layer (120).

The digital image obtained at step (704), after masking at step (705), and the digital image obtained at step (709), after masking at step (710), are combined at step (711) to form the resulting composite digital Images. The composite digital image obtained at step (711) is then decoded at step (712) using a decoder (including error correction) and the code pattern data contents are extracted (134). Combining two digital images at step (711) can be achieved using known processing algorithms

- 20 044693 digital images that stitch two digital images and adjust contrast and intensity throughout machine-readable markings. Another possibility is to perform the following operations on two digital images A and B of the security marking (100), respectively taken at viewing angles close to Θ1 and Θ2, as indicated above, and placing a partial code pattern from image A (corresponding to the first part of the code pattern (134)), and constructing a sampling grid using standard code detection methods;

generating a binary representation B1 of a partial code pattern of image A;

placing a partial code pattern from image B (corresponding to the second part of the code pattern (134)), and constructing a sampling grid using standard code detection methods;

generating a binary representation B2 of the partial code pattern of image B;

combining the resulting binary representations B1 and B2 of the code patterns of images A and B by applying a Truth table to each corresponding module of the binary representations (i.e., the black module in B1 and the black module in B2 give the black module of the combined binary representation CB, the white module in B1 and a white module in B2 gives a white module in SV, a black (respectively white) module in B1 and a white (respectively black) module in B2 give a white module in SV); and a standard code error correction algorithm is applied to the resulting combined binary representation of the CB (full) code pattern to eliminate potential errors that may be present, and an error-free composite digital image of the code pattern is obtained (134).

Estimation of the position of the imager (202) can be performed using several known methods. Two of them are respectively schematically illustrated in FIG. 8A and FIG. 8B.

One possible position estimation method is as follows (see FIG. 8A): a machine-readable marking (130) is applied to a flat surface, the resulting digital image sequence (801) is sent to a commercially available planar extraction library (802) (such as, for example, Vuforia, ARCore or ARKit). This library returns the estimated position of the imager relative to the plane of the applied machine-readable marking (803).

Another possible position estimation method is as follows (see FIG. 8B) (coordinate tags, such as CCTag, can be added to the security marking if the reference pattern is not suitable for position estimation): the acquired digital image (804) is processed (via conventional image processing) to extract information about the graphical execution (i.e., the location of the reference pattern) (805) and detect (806) the reference pattern (133) using a known pattern mapping or a specific detector to the type of marking (in this case, a QR code) , for example, CCTag, ARTag, ARToolKit tag, etc., and provides position estimation (807) using the detected location of the reference pattern, for example, using the SolvePnP program from the OpenCV library (see, for example, the article by V. Lepetit and al ., An accurate o(n) solution to the pnp problem International Journal of Computer Vision, 81(2), pp. 155-166, 2009). However, many other position estimation methods are known to one skilled in the art.

Other types of machine-readable markings may be used to implement the present invention, such as a DataMatrix with an L-shaped reference pattern (see FIG. 5C).

In fig. 9 shows an example of a secure document (150) according to the present invention, in this case a John Doe user ID card with printed identification data (151) indicating the user's name, address, and date of birth. This security document was issued to the user by an authorized body, and this authorized body applied a security mark (100) to the document. The code pattern (134) of the machine-readable marking (130) of the security marking (100) contains an encoded digital identification of the user (in this case corresponding to the printed identification) and a digital signature of this digital identification. The digital signature is provided by the authority and is obtained using a cryptographic key (stored in the authority's database along with the corresponding decryption key). The security marking (100) corresponds to the marking shown in FIG. 5C (i.e. two-dimensional barcode DataMatrix GS1). Depending on the data storage capacity of the machine-readable marking, additional identification data (eg, biometric data of the user, in some cases a photograph of the user) may be encoded in the code pattern (130).

In fig. 10 is a flowchart of the method for verifying the protected document shown in FIG. 9, controller. This method of verifying a security document (150) by a controller using a portable device (200), as shown in FIG. 6, additionally equipped with a communication unit, configured to send and receive data via the communication network (CN) to the server (S) of the authorized body, connected to the database (DB) (see also Fig. 11), in which the cryptograph is stored. 044693 a physical key K used to digitally sign the encoded data in the code pattern (134) together with the corresponding decryption key K', the method comprising the steps (see also FIG. 6):

(1000) placement (by the controller) of protective markings (100) on the protected document (150) within the field of view of the image generator (202) of the portable device (200);

(1001) illuminating the security marking (100) of the protected document (150) with a light source (201) of the portable device (200);

(1002) obtaining a first digital image of the illuminated magnetically induced layer (120) by the imager (202) at a first viewing angle Θ1 associated with a first elevation angle γ1 of magnetically oriented reflective plate-like magnetic or magnetizable pigment particles in a first zone (120a) of said magnetically -induced layer (120), and storing the resulting first digital image in memory;

(1003) obtaining a second digital image of the illuminated magnetically induced layer (120) by the imager (202) at a second viewing angle θ ₂ associated with a second elevation angle γ ₂ of magnetically oriented reflective plate-like magnetic or magnetizable pigment particles in a second zone (120b) said magnetically induced layer (120), and storing the resulting second digital image in memory;

(1004) generating, by image processing by an image processor, a composite digital image of a code pattern (134) from the stored first digital image and the stored second digital image by registration with respect to a reference pattern (133) (in this case an L-shaped DataMatrix) detected in the first digital image and a second digital image, a first pattern portion (134) that corresponds to a first pattern pattern region (134a) detected in the first digital image, and a second pattern pattern portion (134) that corresponds to a second pattern pattern region (134b) (134), found in the second digital image;

(1005) reading and decoding the code pattern (134) from the received composite digital image, and extracting the user identification data UID and the digital signature UIDS of the specified user identification data from the decoded pattern data, using image processing and decoding operations of the processor, and storing the extracted identification data user data UID and digital signature UIDS in memory;

(1006) sending a first message (M1) containing the extracted user identification data UID and digital signature UIDS stored in the memory by the communication unit to the server (S);

(1007) decrypting at the server (S) the extracted digital signature UIDS received in the first message (M1) from the portable device (200) using the decryption key K' stored in the database (DB), and checking the match of the extracted user identification data UIDs received in the first message (M1), with the extracted UIDS digital signature decrypted;

(1008) in case of a match, send back to the portable device (200) a server message (SM) about the successful verification of the user identification data and (1009) in the case of a discrepancy between the extracted user identification data UID received in the first message (M1) and the decrypted extracted digitally signing the UIDS, sending back to the portable device (200) a server alert (SALM) about unsuccessful verification of the user's identification data.

If a server-side alert (SALM) is received by the portable device (200), the controller using the portable device is informed that the security document is not genuine and, for example, can take action against the user who issued the counterfeit security document.

A system configured to perform the above operations to enable a controller to verify a user's security document (as shown in FIG. 9) is illustrated schematically in FIG. 11. The view shows the server (S) of the authorized body that issued the protected document (150) to the user, connected to a database (DB) in which the cryptographic key K and its corresponding decryption key K' are stored. The controller handheld device (200) is a smartphone. In this case, a server message (SM) is displayed on the smartphone screen indicating successful verification of the protected document (for example, OK information is displayed).

The above-mentioned method for verifying a user's security document according to the present invention and the corresponding system for performing the operations necessary to carry out said verification may have some variations including deep authentication of security markings. In particular, when the verification method is used to provide the user with access to some online service (for example, a banking transaction, online registration, online payment, etc.).

In an embodiment of the first variant of the verification method, a user is considered with

- 22 044693 by a suitably programmed smartphone (eg, by downloading a suitable image processing and decoding application to run on the smartphone), which also performs the same operations as the handheld device (200) of the present invention, as shown in FIG. 6. The smartphone is equipped with a communication unit configured to send and receive data via a communication network (CN) to the server (S) of the authorized body that issued the identity card to the user corresponding to the security document (150) shown in FIG. 9. The server(s) are connected to a database (DB) storing a cryptographic key K used to digitally sign the encoded data in the code pattern (134) of the machine-readable marking (130) of the security marking (100) applied to the identity card, along with the corresponding decryption key K'. The following steps are carried out:

(1200) placement (by the user) of a protective marking (100) on a protected document (150) within the field of view of the image generator (202) of a smartphone (200);

(1201) illuminating the security marking (100) of the security document (150) with a light source (201) of the smartphone (200), wherein the illumination is obtained by the flash light of the user's smartphone;

(1202) obtaining (by the user) a first digital image of the illuminated magnetically induced layer (120) by the imager (202) at a first viewing angle Θ1 associated with a first elevation angle γ1 of magnetically oriented reflective plate-like magnetic or magnetizable pigment particles in a first zone (120a) of said magnetically induced layer (120), and storing the resulting first digital image in the smartphone’s memory;

(1203) obtaining (by the user) a second digital image of the illuminated magnetically induced layer (120) by the imager (202) at a second viewing angle θ ₂ associated with a second elevation angle γ ₂ of magnetically oriented reflective plate-like magnetic or magnetizable pigment particles in a second zone (120b ) the specified magnetically induced layer (120), and storing the resulting second digital image in the memory of the smartphone;

(1204) generating, by image processing by the smartphone processor, a composite digital image of the code pattern (134) from the stored first digital image and the stored second digital image by registration with respect to a reference pattern (133) (L-shaped DataMatrix) detected in the first digital image and a second digital image, a first pattern portion (134) that corresponds to a first pattern pattern region (134a) detected in the first digital image, and a second pattern pattern portion (134) that corresponds to a second pattern pattern region (134b) (134), found in the second digital image;

(1205) reading and decoding the code pattern (134) from the received composite digital image, and extracting from the decoded code pattern data the user identification data UID and the digital signature UIDS of the specified user identification data, through image processing and decoding operations of the processor of the smartphone, and storing the extracted user identification data UID and digital signature UIDS in the smartphone memory;

(1206) sending a first message (M1) containing the extracted user identification data UID and digital signature UIDS stored in the memory by the smartphone communication unit (200) to the server (S);

(1207) decrypting at the server (S) the extracted digital signature UIDS received in the first message (M1) from the smartphone (200) using the decryption key K' stored in the database, and checking the match of the extracted user identification data UID received in the first message (M1), with the extracted UIDS digital signature decrypted;

(1208) illuminating the magnetically induced layer (120) with a light source (201) and obtaining a plurality of digital images, for example ten images, of the illuminated magnetically induced layer (120) by an imager (202), the imager (202) being positioned for each other digital image at a corresponding different viewing angle θ relative to said magnetically induced layer (120), by moving the imager (202) relative to the magnetically induced layer (120) parallel to the plane of the substrate (110) (this is the movement, in this case displacement, of the imager smartphone is carried out by the user);

(1209) for each received digital image, the smartphone processor calculates, respectively, the corresponding average intensity I of light reflected by the magnetically induced layer (120) and collected by the image former (202) at the corresponding viewing angle θ, and stores (in the smartphone memory) the calculated average reflected light intensity values and corresponding viewing angles to obtain the corresponding reflected light intensity curve Ι(θ);

(1210) the communication unit of the smartphone (200) sending a second message (M2) to the server (S) via the communication network (CN) containing the received reflected light intensity curve Ι(θ);

- 23 044693 (1211) comparison on the server (S) of the curve Ι(θ) of the intensity of reflected light, received in the second message (M2), with the reference curve Iref(θ) of the intensity of reflected light for the specified magnetically induced layer (120), stored in the database data (DB);

(1212) determining at the server (S) the authenticity of the magnetically induced layer (120) based on the comparison result;

(1213) if the magnetically induced layer (120) is determined to be genuine, sending back to the smartphone (200) a server message (SM') indicating successful verification of the user's identity along with an indication that the security marking (100) is genuine, and sending by the server (S) via the communication network (CN) a server authorization message (SAM) to the user's smartphone (200) containing access data allowing the user to access the online service (for example, a password for online registration); and (1214) if the extracted user identification UID received in the first message (M1) does not match the decrypted extracted digital signature UIDS, or the magnetically induced layer (120) is determined to be fake, sending back to the smartphone (200) a server alert ( SALM) about unsuccessful verification of user identification data.

In an embodiment of the second verification method in which the reflectance curves Ι(θ) and I _ref (θ) are compared using the handheld device (200), still considering a user with a suitably programmed smartphone that also performs the same operations as the handheld device. a device (200) according to the present invention, as shown in FIG. 6. The smartphone is equipped with a communication unit configured to send and receive data via a communication network (CN) to the server (S) of the authorized body that issued the identity card to the user corresponding to the security document (150) shown in FIG. 9. The server(s) are connected to a database (DB) storing a cryptographic key K used to digitally sign the encoded data in the code pattern (134) of the machine-readable marking (130) of the security marking (100) applied to the identity card, along with the corresponding decryption key K'. The following steps are carried out:

(1300) placement (by the user) of a protective marking (100) on an identity card (150) within the field of view of the image generator (202) of a smartphone (200);

(1301) illuminating the security marking (100) of the security document (150) with a light source (201) of the smartphone (200), the illumination being obtained by the flash light of the user's smartphone;

(1302) obtaining (by the user taking pictures) a first digital image of the illuminated magnetically induced layer (120) by the imager (202) of the smartphone (200) at a first viewing angle Θ1 related to the first elevation angle γ1 of the magnetically oriented reflective plate magnetic or magnetizable pigment particles in the first zone (120a) of said magnetically induced layer (120), and storing the resulting first digital image in the memory of the smartphone;

(1303) obtaining (by the user) a second digital image of the illuminated magnetically induced layer (120) by the imager (202) at a second viewing angle θ ₂ associated with a second elevation angle γ ₂ of magnetically oriented reflective plate-like magnetic or magnetizable pigment particles in a second zone (120b ) the specified magnetically induced layer (120), and storing the resulting second digital image in the memory of the smartphone (200);

(1304) generating, by image processing by the smartphone processor, a composite digital image of a code pattern (134) from the stored first digital image and the stored second digital image by registration with respect to a reference pattern (133) (L-shaped DataMatrix) detected in the first digital image and the second digital image, a first part of a code pattern (134) that corresponds to a first region (134a) of a code pattern (134) detected in the first digital image, and a second part of a code pattern (134) that corresponds to a second region (134b) of a code pattern (134 ), detected in the second digital image;

(1305) reading and decoding the code pattern (134) from the received composite digital image, and extracting the specified user identification data from the decoded code pattern data UID and digital signature UIDS of the specified user identification data, using image processing and decoding operations of the smartphone processor (200), and storing the extracted user identification data UID and digital signature UIDS in the memory of the smartphone;

(1306) sending a first message (M1) containing the extracted user identification data UID and digital signature UIDS stored in memory by the smartphone communication unit (200) to the server (S);

(1307) decrypting at the server (S) the extracted digital signature UIDS received in the first message (M1) from the smartphone (200) using the decryption key K' stored in the database (DB) and checking the match of the extracted user identification data UID adopted in the first

- 24 044693 message (M1), with the extracted UIDS digital signature decrypted;

(1308) in case of a match, sending back to the smartphone (200) a server message (SM) about successful verification of the user’s identification data;

(1309) in the case of delivery by the server (S) of a server message (SM) about successful verification of the user’s identification data, illumination (by the user) of the magnetically induced layer (120) of the machine-readable marking (130) on the identity card (150) with a light source (201) and obtaining multiple digital images of the illuminated magnetically induced layer (120) by the imager (202) of the smartphone (200), and the imager (202) is placed for each other digital image at a corresponding different viewing angle θ relative to the specified magnetically induced layer (120), by moving the imager (202) relative to the magnetically induced layer (120) parallel to the plane of the substrate (in this case, the user moves the imager parallel to the security marking);

(1310) for each acquired digital image, the processor calculates, respectively, the corresponding average intensity I of light reflected by the magnetically induced layer (120) and collected by the imager (202) at the corresponding viewing angle θ, and determines using the calculated average values of the reflected light intensity and the corresponding viewing angles of the corresponding reflected light intensity curve I(0);

(1311) comparing, by the smartphone processor (200), the reflected light intensity curve I(0) with a reference reflected light intensity curve I _ref (0) for said magnetically induced layer (120) stored in the memory of the smartphone;

(1312) determining by the processor of the smartphone (200) the authenticity of the magnetically induced layer (120) based on the comparison result, and, in the case of determining the magnetically induced layer (120) as genuine, sending it to the server (S) by the communication unit of the smartphone via the communication network (CN), messages (M) about the authenticity of the security marking (100); and (1313) in the event that the server (S) receives a message (M) from a smartphone (200) about the authenticity of the security marking (100), the server (S) sends back via the communication network (CN) a server authorization message (SAM) to the smartphone ( 200) of the user, containing access data allowing the user to access the online service.

Examples of security markings

Examples E1 to E4 were carried out using a UV-visible screen printing ink according to the formula shown in the table and the first and second magnetic assemblies described hereinafter.

Table

Ingredients wt. % Epoxyacrylate oligomer (APpeh) 30.1 Trimethylolpropane triacrylate monomer (APpeh) 21.0 Tripropylene glycol diacrylate monomer (APpech) 21.5 Genorad 16 (Rahn) 1.1 Aerosil 200 (Evonik) 1.1 Speedcure TPO-L (Lambson) 2.2 Irgacure® 500 (IGM) 6.4 Genocure® EPD (Rahn) 2.2 BYK® 371 (BYK) 2.2 Tego Foamex N (Evonik) 2.2 magnetic pigment particles (*) 10.0

(*) 5-layer lamellar magnetic pigment particles having a metallic silver color and flake shape with a d ₅₀ diameter of approximately 19 µm and a thickness of approximately 1 µm, obtained from VIAVI Solutions, Santa Rosa, California.

Magnetic field generating device for biaxial orientation (Fig. 12A-B)

A magnetic assembly was used to biaxially orient the pigment particles. The magnetic assembly contained nine bar dipole magnets (M1-M9).

Each of the nine dipole bar magnets (M1-M9) had the following dimensions: 100 mm (L1)x10 mm (L2)x10 mm (L3). The device generating the magnetic field was built into a non-magnetic holder made of polyoxymethylene (POM) (not shown) with the following dimensions: 250 mm x 150 mm x 12 mm. Nine dipole bar magnets (M1-M9) were made of NdFeB N40.

Nine dipole bar magnets (M1-M9) were placed in a row at a distance (d1) of approximately 10 mm from each other, with the top surfaces of the nine dipole bar magnets (M1M9) being placed flush. Magnetic axis of each of the nine bar dipole magnets (M1-M9)

- 25 044693 was substantially parallel to the thickness (L3) of said magnets, with the magnetic direction of two adjacent magnets (M1-M9) pointing in the opposite direction (alternating magnetization). The magnetic field was essentially uniform and the magnetic field lines were essentially coplanar in one region A.

Device generating a magnetic field for uniaxial orientation (Fig. 13)

A device generating a magnetic field was used to uniaxially orient the pigment particles. The device generating the magnetic field contained two dipole bar magnets (M1, M2) and two pole pieces (P1, P2).

Each of the two dipole bar magnets (M1, M2) had the following dimensions: 40 mm (L1) x 40 mm (L2) x 10 mm (L3). Two dipole bar magnets (M1, M2) were made of NdFeB N42.

Two dipole bar magnets (M1, M2) were placed at a distance (d1) of approximately 40 mm from each other. The magnetic axis of each of the two bar dipole magnets (M1, M2) was substantially parallel to the length (L1) of the said magnets, and the magnetic direction of the two dipole bar magnets (M1, M2) pointed in the same direction.

Each of the two pole pieces (P1, P2) had the following dimensions: 60 mm (L4) x 0 mm (L5) x 3 mm (L6). The two pole pieces (P1, P2) were made of iron (ARMCO®).

Two dipole bar magnets (M1, M2) and two pole pieces (P1, P2) were placed so as to form a rectangular cuboid with a centered rectangular cuboid void, said void consisting of a region A in which the magnetic field was substantially uniform, and the magnetic field lines were substantially parallel to each other, so that the distance (d2) between the two pole pieces (P1, P2) was approximately 40 mm, i.e. the distance (d2) between the two pole pieces (P1, P2) was the length (L1) of the two dipole bar magnets (M1, M2). As shown in FIG. 13, the magnetic field was essentially uniform in region A.

E1 (Fig. 2, Fig. 12A-B, Fig. 14A)

The UV-visible curable screen printing ink from Table 1 was applied to a piece of black coated paper (45 mm x 60 mm) (110) to form a first coating layer (30 mm x 19 mm) (120a), wherein the said application step was carried out using a laboratory screen printing apparatus using a 90T screen to form a layer whose thickness was approximately 20 µm.

While the coating layer (120a) was still in a wet and not yet at least partially cured state, the substrate (110) was placed on top of the center of a support plate (300 mm x 40 mm x 1 mm) made of high density polyethylene (HDPE). The carrier plate carrying the substrate (110) was moved at a speed of approximately 10 cm/s adjacent to the magnetic field generating device (as illustrated in FIG. 12A), at a distance (d5) of approximately 20 mm between the surface of the magnetic field generating device facing to the substrate (110), and the nearest edge of the first coating layer (120a), and the height between said nearest edge of the first coating layer (120a) and the bottom surface of the magnetic field _generating device was half the length ( ^1/2 L1) of the dipole bar magnets ( M1-M9). The carrier plate carrying the substrate (110) was simultaneously moved at an angle a formed by the first coating layer (120a) and tangent to the magnetic field lines of the magnetic field generating device in the region A in which the magnetic field was uniform, and said angle a had value of approximately 20°, which allowed the particles to be oriented at an elevation angle of approximately 20°, which allowed the particles to be oriented at an elevation angle γ1 of approximately 20.

The first layer (120a) of the coating is at least partially cured to form a first zone (120a), said curing being carried out using a curing unit (UV LED lamp (FireFly 395 nm, 4 W/cm ² , from Phoseon)) located above the substrate path at a distance (d4) of approximately 15 mm for the center of the length (L1) of the dipole bar magnet (M1-M9), next to the space between the eighth and ninth dipole magnets (M8 and M9) and next to the ninth dipole bar magnet (M9 ) at a distance (d3) of approximately 10 mm.

UV-visible curable screen printing ink from Table. 1 was applied to a piece of black coated paper (110) to form a second coating layer (30 mm x 19 mm) (120b) adjacent (along the 19 mm edge) to the first zone (120a), using the same 90T laboratory screen printing apparatus. The resulting combined coating layers (120a and 120b) had a total surface area of 30 mm x 38 mm.

While the second coating layer (120b) was still in a wet and not yet at least partially cured state, the substrate (110) was placed on top of the center of a support plate (300 mm x 40 mm x 1 mm) made of high density polyethylene (HDPE). The carrier plate carrying the substrate (110) was moved at a speed of approximately 10 cm/s adjacent to the same magnetic field generating device (as illustrated in FIG. 12A-B) at the same distance (d5) of approximately 20 mm between the surface of the magnetic field generating device facing the substrate (110) and the nearest edge of the second coating layer (120b), and the height between said nearest edge of the second coating layer (120b) and the bottom surface of the magnetic field generating device was half the length ( ^1/2 L1) bar dipole magnets (M1-M9) _. The carrier plate carrying the substrate (110) was simultaneously moved at an angle a formed by the coating layer (120b) and tangent to the magnetic field lines of the magnetic field generating device in a region A in which the magnetic field was uniform, and said angle a was approximately 160°, which allowed the particles to be oriented at an elevation angle of approximately 160°, which allowed the particles to be oriented at an elevation angle γ ₂ of approximately 160°.

The second layer (120b) of the coating was at least partially cured to form a second zone (120b), said curing being carried out using a curing unit (UV LED lamp (FireFly 395 nm, 4 W/cm ² , from Phoseon)) located above the substrate path at a distance (d4) of approximately 15 mm for the center of the length (L1) of the dipole bar magnet (M1-M9), next to the space between the eighth and ninth dipole magnets (M8 and M9) and next to the ninth dipole bar magnet (M9 ) at a distance (d3) of approximately 10 mm to form a second zone (120b), which provided a magnetically induced image (120).

A QR code (25 mm x 25 mm) was inkjet printed on a magnetically induced image (120), so that the QR code was placed in the center of the specified layer (120), with black ink (Sicurajet SUV Black from Siegwerk) using a Konica Minolta print head (KM1024i). The inkjet printed QR code was at least partially cured with a mercury lamp (500 mJ/cm ² ).

The resulting sample of Example E1 is shown in FIG. 14A (left: viewing angle θ1+22°; right: viewing angle θ2-22°).

E2 (Fig. 2C, Fig. 13, Fig. 14B)

UV-visible curable screen printing ink from Table. 1 was applied to a piece of black coated paper (45 mm x 60 mm) (110) to form a first coating layer (30 mm x 19 mm) (120a), this application step was carried out using a laboratory screen printing device using a 90T screen to form a layer, the thickness of which was approximately 20 µm.

While the first layer (120a) of coating was still in a wet and not yet at least partially cured state, the substrate (110) was placed over the center of a support plate (300 mm x 40 mm x 1 mm) made of high density polyethylene (HDPE). A support plate carrying the substrate (110) was placed at the center of the void of the magnetic assembly, as illustrated in FIG. 13, at an angle a formed by the first coating layer (120a) and tangent to the magnetic field lines of the magnetic field generating device in the region A in which the magnetic field was uniform, the angle being approximately 8°, allowing the particles to be oriented at an angle elevation γ1 approximately 8°.

After approximately 1 second, the first coating layer (120a) was at least partially cured to form a first zone (120a), which curing was accomplished using a curing unit (UV LED lamp (FireFly 395 nm, 4 W/cm ² , from Phoseon), as illustrated in Fig. 13.

UV-visible curable screen printing ink from Table. 1 was applied to a piece of black coated paper (110) to form a second coating layer (30 mm x 19 mm) (120b) adjacent (along the 19 mm edge) to the first zone (120a), using the same 90T laboratory screen printing apparatus. The resulting combined coating layers (120a and 120b) had a total surface area of 30 mm x 38 mm.

While the second coating layer (120b) was still in a wet and not yet at least partially cured state, the substrate (110) was placed on top of the center of a support plate (300 mm x 40 mm x 1 mm) made of high density polyethylene (HDPE). A support plate carrying the substrate (110) and the second coating layer (120b) was placed in the center of the void of the magnetic assembly, as illustrated in FIG. 13, at an angle a formed by the second coating layer (120b) and tangent to the magnetic field lines of the magnetic field generating device in the region A in which the magnetic field was uniform, the angle being approximately 172°, allowing the particles to be oriented at an angle elevation γ ₂ approximately 172°.

After approximately 1 second, the second coating layer (120b) was at least partially cured to form a second zone (120b), which curing was accomplished using a curing unit (UV LED lamp (FireFly 395 nm, 4 W/cm ² , from Phoseon) with the formation of a second zone (120b), which provided a magnetically induced layer (120).

A QR code (25 mmx25 mm) was inkjet printed on a magnetically induced layer (120), such that the QR code was placed in the center of said layer (120) with black ink (Sicurajet SUV Black from Siegwerk) using a Konica Minolta print head ( KM1024i). The inkjet printed QR code was at least partially cured with a mercury lamp (500 mJ/cm ² ).

-

Claims (15)

The resulting sample of Example E2 is shown in FIG. 14V (left: viewing angle θ1+10°; right: viewing angle θ ₂ -10°). E3 and E4 (Fig. 2C, Fig. 12A-B, Fig. 13, Fig. 14C-D) A 10 mm x 10 mm piece of substrate (110) obtained in Example E1 or Example E2, carrying only the magnetically induced layer (120) (10 mm x 5 mm), was applied and adhered to a piece of white coated paper (50 mm x 50 mm). A QR code (25 mm x 25 mm) was inkjet printed on a magnetically induced layer (120), such that the inactive area of the QR code was placed on top of said layer (120) with black ink (Sicurajet SUV Black from Siegwerk) using a Konica Minolta print head (KM1024i), as illustrated in FIG. 14C and 14D. The inkjet printed QR code was at least partially cured with a mercury lamp (500 mJ/cm ² ). The resulting sample of Example E3 is shown in FIG. 14C (left: viewing angle θ1+22°; right: viewing angle θ ₂ -22°). The resulting sample E4 is shown in FIG. 14D (left: viewing angle θ1+10°; right: viewing angle θ ₂ -10°). The foregoing subject matter is to be considered illustrative and not limiting, and serves to provide a better understanding of the present invention as defined by the independent claims. CLAIM 1. Security marking (100), characterized in that it contains a flat substrate (110); a magnetically induced layer (120) of material containing magnetically oriented reflective plate-like magnetic or magnetizable pigment particles, wherein the magnetically induced layer is deposited on a substrate (110) and contains a first zone (120a), wherein the flat edges of said magnetically oriented reflective plate-like magnetic or magnetizable particles magnetizable pigment particles are oriented in a first direction, and a second zone (120b) different from the first zone (120a), wherein the flat faces of said magnetically oriented reflective plate-like magnetic or magnetizable pigment particles are oriented in a second direction different from the first direction, wherein the plate-like particles in the first zone (120a) have flat faces with an elevation angle γ1 relative to the substrate plane (110) and lamellar particles in the second zone (120b) have flat faces with an elevation angle γ ₂ relative to the substrate plane (110), each acute angle of the flat faces relative the plane of the substrate is in the range from about 5 to about 25°; a machine-readable marking (130) comprising a reference pattern (133) and a code pattern (134) representing encoded data, the machine-readable marking (130) being respectively applied either to the top edge (121) of the magnetically induced layer (120) or to a substrate (110) between said substrate and the rear edge (122) of the magnetically induced layer (120), wherein the first region (134a) of the code pattern (134) is located in front of the first zone (120a), and the remaining second region (134b) of the code pattern ( 134) is located in front of the second zone (120b). 2. Protective marking according to claim 1, characterized in that: a) said pigment particles contain a magnetic metal selected from the group consisting of cobalt, iron, gadolinium and nickel; a magnetic alloy of iron, chromium, manganese, cobalt, nickel or a mixture of two or more of them; magnetic oxide of chromium, manganese, cobalt, iron, nickel or a mixture of two or more of them; or a mixture of two or more of them; or b) The code pattern is any of a 1D barcode, a stacked 1D barcode, a 2D barcode, and a 3D barcode. 3. Security marking according to any one of claims 1 and 2, characterized in that the first zone (120a) and the second zone (120b) of the magnetically induced layer (120) belong to the same layer of material. 4. Security marking according to any one of claims 1 and 2, characterized in that the first zone (120a) and the second zone (120b) of the magnetically induced layer (120), respectively, belong to the first sublayer and the adjacent second sublayer, forming a magnetically induced induced layer (120). 5. Security marking according to any one of claims 1 to 4, characterized in that a machine-readable marking (130) is applied to the upper edge (121) of the magnetically induced layer (120) and encoded with dark symbols, and a dark primer layer (140) is applied to substrate (110), and the back face (122) of the magnetically induced layer (120) is applied to the top face (141) of the dark primer layer (140). 6. Security marking according to any one of claims 1 to 4, characterized in that a machine-readable marking (130) is applied to the upper edge (121) of the magnetically induced layer (120) and encoded with light characters, and a dark primer layer (140), preferably a black primer is applied to the substrate (110), and a back face (122) of the magnetically induced layer (120) is applied to the top face (141) of the dark primer layer (140). 7. Security marking according to any one of claims 1-4, characterized in that the marking is machine readable - 28 044693 (130) is applied to the substrate (110) and encoded with dark symbols. 8. A method for reading and decoding security markings (100) according to any one of claims 1 to 7 using a portable device (200) equipped with a light source (201) configured to supply light, an image former (202) and a processor equipped with a memory and configured to carry out image processing and decoding operations, including the steps of placing a protective marking (100) within the field of view of the image former (202); illuminating the security marking (100) with light supplied by the light source (201); obtaining a first digital image of the security marking (100) by the image generator (202) at a first viewing angle Θ1 associated with the first elevation angle γ1, and storing the obtained first digital image in memory; obtaining a second digital image of the security marking (100) by the image sensor at a second viewing angle θ ₂ associated with a second elevation angle γ ₂ , and storing the resulting second digital image in memory; generating, by image processing by an image processor, a composite digital image of a code pattern (134) from a stored first digital image and a stored second digital image by aligning, with respect to a reference pattern (133) detected in the first digital image and the second digital image, a first part of the code pattern (134), corresponding to a first code pattern area (134a) detected on the first digital image, and a second code pattern part (134) corresponding to a second code pattern area (134b) detected on the second digital image, and storing the resulting composite digital image in a memory; the processor reading and decoding a code pattern (134) from the stored composite digital image. 9. A portable device (200) for reading and decoding the security marking (100) according to any one of claims 1 to 7, comprising a light source (201) configured to supply light; an image generator (202) and a processor equipped with a memory, and configured to carry out the steps of illuminating the security marking (100) with light supplied by the light source (201); obtaining a first digital image of the security marking (100) by the image generator (202) at a first viewing angle Θ1 associated with the first elevation angle γ1, and storing the obtained first digital image in memory; obtaining a second digital image of the security marking (100) by the image sensor at a second viewing angle θ2 associated with a second elevation angle γ2, and storing the obtained second digital image in a memory; generating, by image processing by an image processor, a composite digital image of a code pattern (134) from a stored first digital image and a stored second digital image by aligning, with respect to a reference pattern (133) detected in the first digital image and the second digital image, a first part of the code pattern (134), corresponding to a first code pattern area (134a) detected on the first digital image, and a second code pattern part (134) corresponding to a second code pattern area (134b) detected on the second digital image, and storing the resulting composite digital image in a memory; the processor reading and decoding a code pattern (134) from the stored composite digital image. 10. A protected document (150), issued by an authorized body to the user, characterized in that it contains a security marking (100) according to any of claims 1-7, applied to the protected document (150), with encoded data in a code pattern (134 ) security markings (100) contain digital identification data corresponding to the user, and a digital signature of the specified digital identification data of the user, and the digital signature provided by the authorized body is obtained by signing the digital identification data of the user with a cryptographic key. 11. A method for verifying a user’s protected document (150) according to claim 10 using a portable device (200) according to claim 9, additionally equipped with a communication unit configured to send and receive data via the communication network (CN) to the authorized server (S) a body connected to a database (DB) storing a cryptographic key and a corresponding decryption key, including the steps of placing a security marking (100) within the field of view of the image generator (202); illuminating the security marking (100) of the protected document (150) with a light source (201); obtaining the first digital image of the illuminated security marking (100) by the former - 29 044693 (202) images at the first viewing angle Θ1 associated with the first elevation angle _уь and storing the resulting first digital image in memory; obtaining a second digital image of the illuminated security marking (100) by the image generator (202) at a second viewing angle θ ₂ associated with a second elevation angle γ ₂ , and storing the resulting second digital image in memory; generating, by image processing by an image processor, a composite digital image of a code pattern (134) from a stored first digital image and a stored second digital image by aligning, with respect to a reference pattern (133) detected in the first digital image and the second digital image, a first part of the code pattern (134), corresponding to a first code pattern region (134a) detected on the first digital image, and a second code pattern region (134) corresponding to a second code pattern region (134b) detected on the second digital image; reading and decoding the code pattern (134) from the composite digital image, and extracting from the decoded pattern data the user identification data and the digital signature of the specified user identification data, using image processing and decoding operations of the processor, and storing the extracted user identification data and the digital signature in memory; sending a first message (M1) containing the extracted user identification data and digital signature stored in memory by the communication unit (CN) to the server (S); decrypting at the server (S) the extracted digital signature received in the first message (M1) from the portable device (200) using the decryption key stored in the database (DB), and checking the match of the extracted user identification data received in the first message ( M1), with the received extracted digital signature; and in case of a match, sending back to the portable device (200) a server message (SM) indicating successful verification of the user's identity. 12. The method according to claim 11, including, before the step of sending back the server message to the portable device (200), the preliminary steps of: illuminating the magnetically induced layer (120) with a light source (201) and obtaining a plurality of digital images of the illuminated magnetically induced layer (120) by an imager (202), the imager (202) being positioned for each other digital image at a corresponding different viewing angle θ relative to said magnetically induced layer (120), by moving the image former (202) relative to the magnetically induced layer (120) parallel to the plane of the substrate (110); for each acquired digital image, the processor calculates, respectively, the corresponding light intensity I reflected by the magnetically induced layer (120) and collected by the image former (202) at the corresponding viewing angle θ, and stores the calculated values of the reflected light intensity and the corresponding viewing angles to obtain the corresponding curve Ι(Θ) intensity of reflected light; sending the communication unit a second message (M2) to the server (S) via the communication network (CN) containing the received reflected light intensity curve Ι(Θ); comparison on the server (S) of the reflected light intensity curve Ι(Θ) received in the second message (M2) with the reference reflected light intensity curve I _re f(θ) for the specified magnetically induced layer (120) stored in the database (DB) ; determining on the server (S) the authenticity of the magnetically induced layer (120) based on the comparison result and in the case of determining the magnetically induced layer (120) as genuine, sending back to the portable device (200) a server message (SM) about the successful verification of identification data the user along with an indication that the security mark (100) is genuine, and the server (S) sending over the communication network (CN) a server authorization message (SAM) to the user's communication device containing access data allowing the user to access the service. 13. The method according to claim 11, including in the case of delivery by the server (S) of a server message (SM) about successful verification of user identification data, additional steps: illuminating the magnetically induced layer (120) with a light source (201) and obtaining a plurality of digital images of the illuminated magnetically induced layer (120) by an imager (202), the imager (202) being positioned for each other digital image at a corresponding different viewing angle Θ relative to said magnetically induced layer (120), by moving the image former (202) relative to the magnetically induced layer (120) parallel to the plane of the substrate (110); for each obtained digital image, the processor calculates, respectively, the corresponding intensity I of light reflected by the magnetically induced layer (120) and collected by the image former (202) at the corresponding viewing angle Θ, and determines using the calculated values of the intensity of the reflected light and the corresponding viewing angles of the corresponding curve Ι(θ) of the reflected light intensity; comparing, by the processor, the reflected light intensity curve Ι(Θ) with a reference reflected light intensity curve I _ref (θ) for said magnetically induced layer (120) stored in the memory; determining the authenticity of the magnetically induced layer (120) based on the comparison result and in the case of determining the magnetically induced layer (120) as a genuine sending to the server (S) by the communication unit via the communication network (CN) of a message (M) about the authenticity of the security marking (100 ); and if the server (S) receives a message (M) from a portable device (200) about the authenticity of the security marking (100), the server (S) sends back via the communication network (CN) a server authorization message (SAM) to the user’s communication device containing access data allowing the user to access the service. 14. A system for verifying a protected document (150) according to claim 10, issued by an authorized body to a user, containing a server (S) of an authorized body connected to a database (DB) storing a cryptographic key and a corresponding decryption key, and configured to send and receiving data via communication network (CN); and a portable device (200) according to claim 9 for reading and decoding the security marking (100) according to any one of claims 1 to 7, applied to the security document (150), containing a light source (201) configured to supply light; image generator (202); a communication unit configured to send and receive data via a communication network (CN) to a server (S); and a processor equipped with a memory and configured to perform image processing and decoding operations and perform the steps of: illuminating the security marking (100) with light supplied by the light source (201); obtaining a first digital image of the security marking (100) by the image generator (202) at a first viewing angle Θ1 associated with the first elevation angle γ1, and storing the obtained first digital image in memory; obtaining a second digital image of the security marking (100) by the image sensor at a second viewing angle θ ₂ associated with a second elevation angle γ ₂ , and storing the resulting second digital image in memory; generating, by image processing by an image processor, a composite digital image of a code pattern (134) from a stored first digital image and a stored second digital image by aligning, with respect to a reference pattern (133) detected in the first digital image and the second digital image, a first part of the code pattern (134), corresponding to a first code pattern area (134a) detected on the first digital image, and a second code pattern part (134) corresponding to a second code pattern area (134b) detected on the second digital image, and storing the resulting composite digital image in a memory; the processor reading and decoding a code pattern (134) from the stored composite digital image; wherein the system is further configured to perform the steps of extracting from the decoded code pattern data a user identification data and a digital signature of said user identification data, using image processing and decoding operations of the processor, and storing the extracted user identification data and the digital signature in a memory; sending a first message (M1) containing the extracted user identification data and digital signature stored in memory by the communication unit (CN) to the server (S); decrypting at the server (S) the extracted digital signature received in the first message (M1) from the portable device (200) using the decryption key stored in the database (DB), and checking the match of the extracted user identification data received in the first message ( M1), with the received extracted digital signature; and in case of a match, sending back to the portable device (200) a server message (SM) indicating successful verification of the user's identity. 15. The system according to claim 14, characterized in that the server (S) is further configured to send data over a communication network (CN) to the user's communication device, and the server (S) and portable device (200) are further configured to carry out the steps of the method according to any one of claims 12 and 13, verification of the user’s protected document (150). -