Identification and authentication using liquid crystal material markings

Identification and Authentication using marking by liquid crystal materials

OlAVRonti

Field of the invention

The present invention relates to machine readable marking for the recognition, identification and authentication of individual articles. The marking is performed with a liquid crystal material which is applied to a substrate using various known information printing techniques. The marking can be detected and / or identified by passive detection means, such as optical filters under ηοη-polarized (ambient) light, or else with lighting in polarized light. The marking is applied in the form of inscriptions, such as for example a bar code with one or two dimensions, a matrix code or other inscriptions of the same kind.

Antecedents

We use different suffer from particular like cigarettes.

consumption.

of the invention today of "Tracking" systems in branches of industry. Many industri.es counterfeit or misappropriate products, in the area of ​​mass-produced items drinks, perfumes, medicines, CDs and DVDs and other types of products from

Counterfeiting and diversion of products is facilitated by batch processing rather than item by item. This type of processing makes it easy to introduce counterfeit or diverted products into the logistics chain. Producers and retailers would like to be able to distinguish their original products from such counterfeit or diverted (parallel imported) products at the item level.

MY

32259Β1 individual put up for sale.

The underlying technical problem has been addressed in the prior art by individually marking each item for sale that enters the supply chain. The prior art markings have been chosen in such a way that they cannot be photocopied, that is to say that concealed markings, invisible to the naked eye or for the photocopier have been used.

In the context of the present invention, a “hidden” marking is any marking or security element which cannot be identified with the naked eye, but whose authentication depends on any detection or reading device, as an optical filter or an electronic authentication device.

In the “Apparent” context of the present invention, a marking any marking or security element on which the authentication does not depend on any detection or reading device identified with the naked eye.

that is to say who can be

In the context of the present invention, “Color” is used to designate a return of light (electromagnetic radiation) with any spectral selectivity by an illuminated object, whether in the visible, infrared or UV range of the electromagnetic spectrum (this is i.e. in the whole wavelength range from 200 to 2500 nm).

The term "visible" is used to refer to a property that can be detected with the naked eye; “detectable” is used for a property which can be detected by an optical device, but not necessarily with the naked eye, and “invisible”

<img file="MA32259B1_D0001.tif" />

<img file="MA32259B1_D0002.tif" />

32259Β1 for a property that cannot be detected with the naked eye. In particular, the term “visible color” corresponds to a return of light with spectral selectivity in the range of wavelengths ranging from 400 to 700 nm, which is detectable with the naked eye.

A first type of individual mark, used to prevent counterfeiting and misappropriation, is disclosed in US Patents 5,569,317, US 5,502,304, US 5,542,971 and US 5,525,798. According to these documents, a bar code is applied. on the article using an ink not detectable in visible light (wavelength 400-700 nm) but which becomes visible when illuminated with UV light (wavelength 200 to 700 nm).

380 nm).

A second type of individual marking is disclosed in US Patents 5,611,958 and US 5,766,324. According to these documents, a bar code is applied to the commercial article using an ink not detectable in visible light, but which can be detected when illuminated with infrared light (wavelength 800 to 1600 nm).

Another type of individual marking, using ink, is disclosed in US Patents 5,360,628 and US 6,612,494. This marking must be simultaneously illuminated with UV and IR light in order to be detected.

Another type of individual marking is based on inks containing upconverting phosphors as described in US Pat. No. 5,698,397.

All the markings mentioned in the cited prior art are concealed markings, which are completely invisible to the eye.

ΜΑ 32259Β1 nu. Reading such hidden markings requires a corresponding detection or reading device capable of detecting or reading the mark. Which can be an inconvenience at the retail center or point of sale where a suitable reading device may not always be available.

Visible markings comprising optically variable elements, for example comprising colors depending on the viewing angle, have been proposed in the prior art as means of authentication for "the man in the street". Among these markings we note the holograms (see Rudolf L. Van Renesee, “Optical Document Security”, 2 ح ”ج ed. 1998, chapter 10), optical thin-film safety devices (idem, chapter 13) and liquid crystal safety devices (idem, chapter 14).

Cholesteric liquid crystals are particularly useful as safety devices. When illuminated with white light, the structure of cholesteric liquid crystals reflects light of a given color which depends on the material in question and which generally varies with the viewing angle and the temperature of the device. The cholesteric material itself is colorless and the observed color is due only to a physical effect of reflection by

the cholesteric helical structure adopted by the liquid crystal material at a given temperature (see JL Fergason, Molecular Crystals, Vol. 1, PP. 293-307 (1966)).

In particular liquid crystal materials, cholesteric liquid crystal polymers (CLCPs), the cholesteric helical structure is "frozen" to a state given by polymerization and therefore rendered insensitive to temperature.

AT

MY

32259Β1 ذح the cholesteric liquid crystal material is applied to a dark or black background, its reflection color is easily visible to the naked eye because the light transmitted by the cholesteric material is largely absorbed by the background, so that the residual light diffused by the background does not modify the perception of the specific reflection of the cholesteric material. By carefully choosing the background color, it is therefore possible to improve the visibility of such an apparent marking.

On a light or white background, the color of the reflection of the cholesteric liquid crystal material is almost invisible due to the superposition of the self-reflection of the cholesteric material and the intense scattering from the background. However, one can still identify the cholesteric liquid crystal material using a circular polarization filter because the material selectively reflects only one of two possible components of circularly polarized light, depending on the chirality of its crystal structure.

Patents ΕΡ-Β1,381,520 and ΕΡ-Α1-1,681,586 relate to birefringent marking and a method for applying it in the form of a liquid crystal layer comprising a non-uniform pattern of regions of different thicknesses. The coating, or layer, of liquid crystals applied to a reflective substrate can create a hidden image which is invisible in ηοη-polarized light but which is made visible in polarized light using a polarizing filter.

US Patent 5,678,863 relates to means of identifying valuable documents which have a paper or polymer region, said region having characteristics of.

X

MY

32259Β1 transparency or translucency - A liquid crystal material is applied to this region to produce an optical effect which differs when viewed in transmission or reflection. The liquid crystal material is in the form

It should be at room temperature and must be enclosed in a containing medium, such as microcapsules, in order to be suitable for use in a printing process such as gravure, roll, spray or inkjet printing. The imprinted liquid crystal region may be in the form of a pattern, for example a bar code. The pattern can be verified by observing, with the eye or with an apparatus, the polarization states of regions having left or right helix liquid crystal shapes.

by letterpress, screen printing and

US Patent 5,789,147 relates to polymerizable ligament crystal monomer coating compositions which can be applied by conventional printing processes such as rotogravure, flexographic, offset, ink printing. Printing inks can be used to produce marking and security inscriptions which are invisible to the human eye. The markings can be detected by their circular polarization or by the angular dependence of their reflected color. Τ5

US Patent 6,899,824 relates to a process for printing or coating a substrate with a multilayer made of a liquid crystal composition and at least one non-liquid crystal layer. The process and the printed substrate serve to produce counterfeit proof articles. The preferred methods for applying these prints or coatings are screen printing, planographic printing.

flexographic and typographic.

ΜΑ 32259Β1

٦

However, none of the markings set forth in the prior art address the technical problem underlying "tracking" applications where there is a need, not only for individual machine-readable item coding with security marking. ! 'counterfeit proof, but also an easy authentication of the marking with the eye

“Tracking” applications are known in the prior art, for example in the postal services, in which each piece of mail is individually marked and monitored throughout its delivery chain. The most widely used means of marking and identification are bar codes such as ID bar codes, stacked ID bar codes, 2D bar codes or matrix codes.

No effort is made on the authentication aspects in the case of said postal marking, insofar as, as the piece of mail is processed internally by the postal company throughout the delivery chain, no authentication is not required - Postal "tracking" applications are simply focused on

Identification of the Mail Piece However, authentication aspects are of critical importance in retail applications where there is a potential risk of the original items being replaced with counterfeit or diverted items. Therefore, "Tracking" applications in this field must also be combined with at least one security element capable of certifying the authenticity of the article marked as being an original product.

/ i

ΜΑ 32259Β1

In the following, the expression "Secure Tracking" applies to a combination of a "Tracking" application, which allows the identification of an individual item, with at least one security feature which furthermore allows to determine the authenticity of said article.

Technical problem

For “Secure Tracking” applications, in which a commodity in open circulation must be individually marked with respect to its authenticity and identity and tracked throughout its lifespan or for a specific period of time, by For example, for reasons of liability, it is necessary to have a marking which is i) uniquely coded, to be identifiable, ii) machine-readable, iii) non-copiable (proof against counterfeiting), iv) authenticated by the naked eye by a user and V) authenticated by a machine. For some applications it is further desirable that a portion of the marking be invisible to the naked eye.

Summary of the invention

The marking of the present invention, for the secure tracking of an article or an object, comprises a polymeric liquid crystal material having given optical characteristics, allowing its authentication and reading by a machine as well as its authentication by the user. human eye. The carried out on a substrate by a marking process is printing variable information in the form of inscriptions representing a unique code allowing its identification. In addition, the marking is preferably designed such that part of said marking is invisible to the naked eye.

ΜΑ 32259Β1;

The marking of the present invention is applied to articles or objects such as valuable documents, banknotes, passports, identity documents, driving licenses, official authorizations, access documents, stamps, fiscal stamps and banners, transport tickets, event tickets, labels, sheets, packaging, spare parts and consumer products, which therefore bear this marking either directly, applied to their surface, or indirectly, applies on a label itself applied to their surface.

The polymeric liquid crystal material is preferably of the cholesteric (i.e., helical nematic) type; it is also possible to use a nematic ligid crystal (birefrinqent) material for certain applications.

The polymeric liquid crystal material of the mark may be present either as a polymerized liquid crystal material on the surface of a substrate or as pigment flakes of a ligate crystal polymer within a composition of the polymer. coating applied to a substrate.

Said substrate may be any type of substrate, woven or woven, and it may in particular be made of paper, cardboard, wood, glass, ceramic, metal, plastic, textile, leather, etc. ; the substrate may be coated or uncoated or comprise a sealed or non-sealed surface.

The polymeric liquid crystal material of the marking preferably contains other security materials which are present in order to improve its resistance to counterfeiting. These

ΜΑ 32259Β1 safety materials are selected from a group comprising inorganic luminescent compounds, organic luminescent compounds, IR absorbers, materials

<td>magnetic.</td><td>the</td><td>markers</td><td>forensic</td><td>and their</td>

<td>5 combinations.</td><td></td><td></td><td></td><td></td>

<td>Said material</td><td>of</td><td>security can</td><td>to be present</td><td>as simple</td>

<td>additive, or.</td><td colspan="2">according to nature</td><td>material</td><td>of security.</td>

also as an οο-polymerized component of the liquid crystal pigment, the composition of the liquid crystal precursor or the ink binder. In particular, security materials comprising an acrylic or vinyl function are easily co-polymerized into a corresponding main polymer. The security material can also be grafted, that is to say chemically bonded, to a pre-existing polymer chain.

The substrate, which represents the background on which the liquid crystal material is applied can be any color; the preferred option being a white background to achieve a marking invisible to the naked eye in the sense that no visible color is observed. Another preferred option is a reflective metallic background, particularly in the case of a nematic (birefringent) liquid crystal material - In general, the substrate can be selected from a group comprising reflective, colored and transparent substrates.

To facilitate authentication by a human user, it is preferred that at least a portion of the background on which the liquid crystal material is applied has a contrasting color, for example red, green, blue or black, which in combination with the crystal marking. liquids, makes it possible to perceive with the naked eye a visible color and a change of color in

<img file="MA32259B1_D0003.tif" />

<img file="MA32259B1_D0004.tif" />

32259Β1 depending on the viewing angle.

Said substrate is therefore preferably a patterned substrate comprising at least two areas of different colors, each chosen from the group of white, black, visibly colored, reflective, transparent areas and their combinations. It is therefore obvious to those skilled in the art that the surface of the substrate carrying the liquid crystal material may have two or more colored areas below the liquid crystal material.

The surface of the substrate on which the liquid crystal material is applied, may furthermore bear inscriptions which may be of any shape or color, such as a pattern, logo, text, ID or 2D bar code, a matrix code, etc. Said inscriptions can be applied by any printing or coating process.

The substrate can also carry at least one security element selected from the group comprising inorganic luminescent compounds, organic luminescent compounds, LR absorbers, magnetic materials and forensic markers and combinations thereof. The security element may be present as inscriptions on the surface of the substrate or embedded (inserted) into the substrate itself.

The polymeric liquid crystal material is preferably present in the form of inscriptions, such as text or a bar code. Preferred entries are selected from a group consisting of one-dimensional, one-dimensional stacked, and two-dimensional bar codes. Symbologies of common bar codes have been discussed in

<img file="MA32259B1_D0005.tif" />

32259Β1

Understanding Barcoding, Pira International Ltd., 2004 (ISBN

85802 917 1)

The liquid crystal marking of the present invention is preferably produced by applying a liquid crystal precursor composition to a substrate and curing the composition to attain the ordered liquid crystal state. Said precursor composition comprises reactive monomers or oligomers of at least one nematic liquid crystal compound. The reactive monomers and oligomers are preferably UV curable; in this case the composition applied is UV cured and also comprises a photoinitiator system, as the expert knows. The ordered liquid crystal state depends on the presence of a chiral dopant. The nematic liquid crystals without chiral dopant adopt a molecular texture which is characterized by its birefringence. Nematic precursors are known from patents Α-0-0 216 712, Β-0-0 847 432 and US-B20 6 589 445.

To produce a cholesteric (i.e., helical nematic) liquid crystal polymer said precursor composition must also include a chiral dopant. Said dopant can be chosen from derivatives of isosorbides and isomannides and of their mixtures, as disclosed in patents ΕΡ-Β-0 847 '432, GB-A-2 330 139 and US-B 6 589 445. Isosorbides are known to induce a right helix and isomannids are known to induce a left helix.

Said dopant induces a helical structure in the nematic liquid crystal compound, characterized by a pitch of the order of the wavelength of visible light, which

<img file="MA32259B1_D0006.tif" />

MY;

32259Β1 causes light to be reflected at determined wavelengths and thus an appearance of interference colors as well as a color change depending on the viewing angle. The light reflected by phases of cholesteric ligid crystals is circularly polarized (left or right) depending on the direction of rotation of the cholesteric helix.

The marking of the present invention is produced by applying the liquid crystal precursor composition to a substrate and then curing said composition on the substrate. Curing is preferably effected by subjecting the applied composition to UV light irradiation which induces polymerization of the reactive monomers and oligomers to form a ligated crystal polymer. The molecular order of the ligid crystal is maintained in this way, i.e. without the nematous texture or

<td>cholesteric</td><td>is</td><td>fixed</td><td>in the state</td><td>present during</td>

<td>!'irradiation.</td><td>In</td><td>the case</td><td>from material to</td><td>liquid crystal</td>

<td>20 cholesteric.</td><td>the</td><td>no 1</td><td>'propeller and with</td><td>him properties</td>

<td>optics like</td><td>the</td><td>color</td><td>reflection and</td><td>the change of</td>

color according to the viewing angle thus remain fixed.

A method for labeling an article or an object therefore comprises the steps of providing an article or an object suitable for being marked and applying at least one polymeric liquid crystal material in the form of inscriptions representing a unique code by a method of labeling. printing of variable information on said article or object. In particular, the unique code represented by said entry may be encrypted information and the method may comprise the step of encrypting said information.

<img file="MA32259B1_D0007.tif" />

ΜΑ 32259Β1

Said liquid crystal precursor composition can be applied to a substrate by any coating or printing technique. The composition is preferably applied by a variable information printing process, [such as continuous type laser or inkjet printing or ؛ drop-on-demand. Said variable إ information printing process allows the marking of each ؛ 'to be coded in a unique way. printed item. إ

For laser printing application, the liquid crystal polymer pigment flakes can be incorporated into the toner composition. For this purpose, the liquid crystal polymer pigment particles are added in a ratio of from 1% to 50% by weight to a toner composition containing a binder resin and, optionally, additives such as charge control agents or waxes.

Said binder resin, present in a ratio ranging from 45% to إ

95% by weight, is composed of thermoplastic polymers like ؛ polyamides, polyolefins, polyurethanes, vinyl resins, epoxies, styrene-butadiene and styrene-acrylate copolymers, or polyester resins, and إ it has a glass transition temperature Tg ranging from 40 إ to 12O٠C, from preferably 60 to oc, and an average polymer particle size between 2 and 30 µm depending on the resolution desired for the printed image. Liquid crystal polymer pigment flakes may be encapsulated in said binder resin.

إ

Optionally, the pigment flakes of liquid crystal polymers incorporated in a toner composition described above can be added to a liquid carrier.

ΜΑ 32259Β1 in a ratio of 5% to 60% by weight, thereby forming a liquid developer, which can then serve as a liquid toner, as the expert knows. Preferred liquid carriers are aliphatic hydrocarbons, alicyclic hydrocarbons and polysiloxanes. Among them, paraffinic or isoparaffinic solvents are preferred.

For application by inkjet printing, the composition also contains an organic solvent to adjust the value of the viscosity of the composition so that it is compatible with the chosen printing process, as is known to the expert. إ

For application by continuous inkjet printing, the composition also contains a conductive agent (a salt) which must be soluble in the composition used. Such a “conductive agent” meets the technical need necessary for the printing process, as the expert knows.

In another embodiment, the crystal marquaqe ؛ The liquids of the present invention are produced by applying to a substrate a coating composition containing إ flakes of liquid crystal polymer pigment in a suitable binder.

Said liquid crystal pigment polymer flakes ؛ are preferably made of liquid crystal polymer ؛ cholesteric, having a light reflection at determined wavelengths (interference color), as well as a color varying according to the viewing angle. Such ; pigments are known to the expert from the patents wo

<td> ؛200</td><td> 1/000755</td><td>Al (</td><td>and</td><td>related documents).</td><td>EP 1</td><td> 213</td><td> 338</td><td>Bl;</td><td>EP 0</td>

<td> 685</td><td>749 B1;</td><td>OF</td><td> 199</td><td>22,158 A1; EP 0 601</td><td> 483</td><td>Al;</td><td>OF</td><td> 44 18</td><td> 490</td>

<td>Al;</td><td>EP 0 887</td><td> 398</td><td>Bl</td><td>, W02006 / 063926, US 5</td><td> 211</td><td> ¾11 ,</td><td>US</td><td> 5 362</td><td> 315</td>

م

MY

32259Β1 and US 6,423,246.

Suitable binders can be chosen from vinyl resins, acrylic resins, styrene-maleic anhydrous copolymer resins, polyacetal resins, polyester resins, polyester resins modified with fatty acids and mixtures thereof. The binder can also be chosen from UV curable monomers and oligomers such as acrylates, vinyl ethers, epoxies and their combinations.

The marking is preferably carried out by inkjet printing. To obtain reliable printing and acceptable print quality, the inkjet apparatus must have a sufficiently large orifice (nozzle) diameter. The diameter of the nozzle should be at least 10 times the average diameter of the liquid crystal pigment polymer flakes. For example, for an average flake diameter of 25 µm, the diameter of the nozzle should be at least 250 µm. Systems having said characteristics are valve-jet printers, a particular form of drop-on-demand inkjet printers.

In general, the method for authenticating an article or an object bearing a marking according to the present invention comprises the steps of a) providing an article or an object bearing a marking according to the present invention, b) illuminating the marking on said article or object with at least one quality of light coming from at least one light source, c) detecting the optical characteristics of said marking by detecting the light reflected by the marking, d) determining the authenticity of the article or the object from the detected optical characteristics of the marking.

/

32259Β1

The marking of the present invention can be authenticated according to a first method by simple visual inspection under ambient lighting. For this purpose, the background to which the liquid crystal material is applied must provide sufficient optical contrast to enable the human observer to detect the reflected color and the color change of the liquid crystal material. Depending on the background, part of the marking may remain almost invisible to the naked eye.

<td>In</td><td>a</td><td>second</td><td>process, the</td><td>marking</td><td>is</td><td>authenticated under</td>

<td>lighted up</td><td>rage</td><td>ambient</td><td>with the help of</td><td>'a way</td><td>of</td><td>passive detection</td>

<td>as</td><td>a</td><td>filtered</td><td>optical. A</td><td>such way</td><td>of</td><td>passive detection</td>

preferred is a right circular filter or one thus determining the direction left circular polarization or juxtaposition of the two. The pitch of the helix of the cholesteric liquid crystal material can be rotated by determining the polarization state of the light reflected from said material. Optionally, the polarization filter can be combined with color filters to reduce the spectral bandwidth to the reflection spectral width of the liquid crystal material, and thereby reduce background contributions. You can use more than one optical filter at a time.

In a third method, the tag is authenticated using circularly polarized light from at least one polarized light source. The liquid crystal material reflects light of different circular polarization differently; it is therefore possible to distinguish materials having a left or right pitch heel from their respective response to circularly polarized light. Optionally, the marking can be illuminated by the source of

ΜΑ 32259Β1 polarized light and observe the light reflected from the marking, through a color filter. More than one polarized light source can be used at a time.

In a fourth method, the marking is authenticated using an electro-optical authentication device. In a first embodiment, said device comprises at least one photocell, combined with a circular polarization filter and / or a circularly polarized light source. In another embodiment, said apparatus comprises an electro-optical camera, such as a linear array of CCD sensors, a two-dimensional array of CCD image sensors, a linear array of CMOS image sensors or a two-dimensional array of image sensors. 'CMOS images, combined with a circular polarized filter and / or with a circularly polarized light source.

Optionally, the circularly polarized filter or the circularly polarized light source of the previous embodiments can be combined with color filters to select a particular spectral range and to improve the contrast ratio between the light reflected from the material to. liquid crystal and that reflected from the bottom.

In general, circular polarization filters can also be replaced by an electro-optical switch of

<td>polarization. We</td><td>know a</td><td>Phone</td><td colspan="2">apparatus</td><td>in! 'art.</td><td>by</td>

<td>example from</td><td>DE patent</td><td> 102</td><td> 11 310</td><td>Β4,</td><td>and it allows</td><td>of</td>

<td>30 select! 'A</td><td>Or other</td><td>of</td><td>states</td><td>of</td><td>polarization</td><td>in</td>

applying a corresponding voltage. ئ

In all cases of liquid crystal materials

ΜΑ 32259Β1

19

إ cholesteric, the labeling of the present invention is

إ authenticated by checking one or more of its properties

characteristics, which are the state of circular polarization

؛ and / or the color variation depending on the viewing angle

5 of the light reflected by the marking. The polarized light source or polarized light detection device or

م both can be chosen to work in

؛ the visible, infrared or UV region of the spectrum

٢ electromagnetic or in a combination of these regions, in

10 depending on the optical characteristics of the marking. [

The tag of the present invention can be identified by reading the inscriptions it represents and then relating the information thus retrieved from the tag to the information.

: ؛ 15 stored in a database. In a mode of

particular achievement, the information represented by

inscriptions of the marking are encrypted and said identification comprises the step of decrypting said information. Of

؛ preferences, entries are read by a camera

20 electro-optical as a network of CCD imaqes sensors or

CMOS.

In general, the process for identifying an item or:

؛ an object bearing a marking according to the present invention

25 comprises the steps of a) providing an article or object bearing a marking according to the present invention, b) illuminating

marking on said article or object with at least one:

quality of light coming from at least one light source, c)

؛ read the inscriptions represented by the marking and

؛ 30 deduce the corresponding information, d) relate the information

retrieved from the inscriptions of the marking to the information recorded in a database, e) obtain the confirmation or denial of the identity of the article or of

<img file="MA32259B1_D0008.tif" />

MY

32259Β1! 'Object.

The identification of an article or of an object and bearing a marking according to the present invention can be carried out with the same configuration or assembly of reading devices as those used for the authentication.

In a first embodiment, said inscriptions are represented by a one-dimensional or two-dimensional bar code and the image recovered by the electro-optical camera in digital form is analyzed with a corresponding algorithm. The information contained in the barcode is retrieved, decrypted if necessary, and compared to the information stored in a database, thus identifying the item and, optionally, updating the database with additional information, for example! the story of the article. The camera can form part of a reading device equipped with its own means of communication or form part of a communication device, such as a portable telephone, the retrieval of the information being carried out using the internal resources of the portable telephone. The database can be located either in the communication device (integrated or exchangeable memory), or, on an external server reached by a communication network.

In a second embodiment, said inscriptions are represented by an alphanumeric code and the image recovered by the electro-optical camera (reading apparatus) in digital form is analyzed with an optical character recognition (OCR) algorithm. The information is retrieved and in a database contained in the stored information the code is compared with data.

<img file="MA32259B1_D0009.tif" />

ΜΑ 32259Β1 thus identifying the article and possibly updating the database. As in the first embodiment,;

the database can be located either in the reading device (integrated or exchangeable memory), or on an external server reached by a communication network. The alphanumeric code can be printed with a standard font or a special machine identifiable font. Or, the alphanumeric code can be read visually and either sent by a communication system (eg Internet or SMS) to a data center to be valid or compared to data supplied with the article in the form of an article. label, reference mark or other alphanumeric code. ج

The marking of the present invention, made of ؛ material Polymeric liquid crystals having determined optical characteristics can be used for the secure tracking of articles, objects or goods with an individualized code, resistant to counterfeiting for the secure tracking of said articles, objects or goods.

Applying an individualized code to a commodity or item requires a variable information printing process. A preferred method of variable information printing in the context of the present invention is selected i from the group consisting of continuous inkjet printing and إ

Drop-on-demand inkjet printing; these printing processes allow rapid, non-contact application;

of said individualized code on surfaces of any type. Said individualized code makes it possible to identify [each individual article at a following stage of its life cycle.

To prevent the exchange of the original article by a

<img file="MA32259B1_D0010.tif" />

ΜΑ 32259Β1 counterfeit bearing a copy of said individualized code, said individualized code must resist counterfeiting. The resistance to counterfeiting can be provided by a particular security material having particular physical, preferably optical, properties; said material can either form part of the marking or be incorporated therein. The particular security material may be a polymeric liquid crystal material having determined optical characteristics, or an additive selected from the group consisting of inorganic luminescent compounds, organic luminescent compounds, IR absorbers, magnetic materials, medical markers. legal and their combinations The marking of the present invention can be used on objects or articles such as valuable documents, banknotes, passports, driving, authorizations identity documents, official's licenses, access documents, stamps, fiscal stamps and banners (in particular for 20 tobacco products and alcoholic beverages), transport tickets, event tickets, labels, sheets , packaging (in particular for pharmaceutical products) and in general! to mark out spare parts and consumer products (in particular with regard to the 25 questions of liability).

The marqueaqe of the present invention, applied to articles, goods or objects, can be used for the secure tracking of such marked articles, goods or objects. Such secure tracking of an article or an object notably comprises the first interchangeable steps of a) applying a marking according to the invention to the article or object to be tracked; and b) record the information about the article

<img file="MA32259B1_D0011.tif" />

ΜΑ 32259Β1 or object marked in a database; as well as the second interchangeable steps of c) authenticating the article or the object according to the authentication method set out here; and d) identifying the article or object, according to the identification method set forth herein, using the information previously stored in the database. Optionally, the database can be updated during these steps with new pieces of information relating to the article or object.

The code applied to the article or object represents digital information which is stored in a database to identify the article or object at a later stage. Said code may be encrypted to protect the information it contains during transfer to and from the database. Said database can form part of a database management system. All types of encryption algorithms are suitable, for example a public-private key of the RSA type.

Said database can be a local database, integrated into the authentication device. Or, it can be a remote database, linked to the authentication device by a wired or wireless connection. It is also possible to regularly update a local database from a remote server.

In another aspect, the present invention relates to the application of the individual marking by a method of printing variable information. Inkjet printing is preferred printing, with either continuous inkjet, drop-on-demand (DOD) or valve-jet inkjet printing process. Industrial jet printers

<img file="MA32259B1_D0012.tif" />

ΜΑ 32259Β1 ink commonly used for numbering and coding applications on packaging lines and printing presses are particularly suitable. Preferred inkjet printers are continuous single nozzle inkjet printers (also referred to as raster or multi-level printers) and drop-on-demand inkjet printers, particularly valve-jet printers.

To achieve fully concealed machine-readable marking, nematic liquid crystal materials are used. To achieve visible or semi-concealed and machine-readable marking, cholesteric or chiral-nematic liquid crystal materials are used.

Description of Figures

In order to better understand the present invention, reference is made to the detailed description of the invention and the accompanying figures.

Fig. 1 schematically shows a cardboard package, for example a pharmaceutical package, bearing representative markings a), b), c) according to the invention, which are imprinted with liquid crystal material at different places on said package. carton:

a) has a Data Matrix code on a particularly dark color background, for example a black background;

b) presents a Data Matrix code on a background of mixed colors, for example comprising parts of dark and light colors;

c) presents a Data Matrix code on a white background.

Fig. 2 shows Images captured of a data matrix code

ECC200 printed with hardened Liquid Crystal (LC) material

ΜΑ 32259Β1 UV on a coated cardboard:

a) Data Matrix LC code recovered from a black background under right circular polarized light with a right circular polarization filter in front of the CMOS camera.

b) Data Matrix LC code recovered from a black / white background under right circular polarized white light with a right circular polarization filter in front of the CMOS camera.

c) Data Matrix LC code recovered from a black / white background under right circular polarized white light without filter in front of the CMOS camera.

d) Data Matrix LC code recovered from a black / white background under unpolarized white light without filter in front of the CMOS camera.

Detailed description of the invention

<td>In one</td><td>first</td><td>fashion</td><td>of</td><td>realization, the</td><td>mark of</td><td>the</td>

<td>present</td><td>invention</td><td>is</td><td>fact</td><td>with a material</td><td>precursor</td><td>at</td>

<td>crystals</td><td>liquids</td><td>who</td><td>is</td><td>applied to the state</td><td>liquid on</td><td>the</td>

<td>20 surface</td><td colspan="2">a substrate</td><td colspan="3">before being polymerized (hardened)</td><td>in</td>

the liquid crystal state ordered by UV light irradiation or by electron beam irradiation, as known to those skilled in the art.

The liquid crystal material applied in this embodiment is therefore a monomeric or oligomeric precursor of a liquid crystal polymer. Said precursor comprises at least one nematic liquid crystal monomer or oligomer, said monomer or oligomer having polymerizable groups. Suitable nematic liquid crystal monomers or oligomers belong to the group of bisacrylates such as

4- [4 - [(1-Oxo-2-propeny!) Oxy] butoxy] -1.4 / acid ester

ΜΑ 32259Β1 Benzoic phenylene.

4- [4 - [(1-Oxo-2-propeny!) Oxy] butoxy] - 2methyl -1, 4-phenylene benzoic acid ester.

4- [4 - [(1-Oxo-2-propeny!) Oxy] hexoxy] - methyl-1,4-phenylene benzoic acid ester.

4- [4 - [(Ι-οχο-2-propeenyl) oxy] butoxycarboxy] -1,4-phenylene benzoic acid ester.

4- [4 - [(1-Oxo-2-propeny!) Oxy] butoxycarboxy] -2-methyl-1,4-phenylene benzoic acid ester, and combinations thereof.

The nematic liquid crystal monomer or oligomer can be present in the precursor material in a range of 10% to 100% by weight.

In the case where the curing is carried out by UV radiation, the precursor material contains at least one photoinitiator system containing at least one photoinitiator and, optionally, a stabilizer. Suitable photoinitiators can be selected from the group consisting of Irgacure (eg Irgacure 369, 651, 907 or 1300), Genomer (eg ΒΡ / EPD) or other free radical initiators.

Suitable stabilizers are Florstab UV-1 made by Kromachem and Genorad 16 made by Rahn.

The photoinitiator can be present in the precursor material in a range of 0.5% to 5% by weight.

To obtain cholesteric phases (that is to say nematic with a helix), said precursor also contains at least one chiral dopant (chiral inducer). Suitable chiral dopants include isomannide derivatives and

<img file="MA32259B1_D0013.tif" />

ΜΑ 32259Β1 of isosorbide, as

(3R, 3aR, 6R, 6aR) -hexahydrofuro [3, 2-b] furan-3,6-diyl bis (4- (acryJoyJoxyethoxy) benzoate), (3R, 3aR, 6R, 6aR) -hexahydrofuro [3 , 2-b] furan-3,6-diyl bis (4- (acryJoyJoxybutoxy) benzoate), إ

I (3R, 3aR, 6R, 6aR) -hexahydrofuro [3,2-b] furan-3,6-diyi ٤ bis (4- (acryloyloxybutoxy) -2-methyibenzoate),

I (3R, 3aR, 6R, 6aR) -hexahydrofuro [3,2-b] furan-3, 6-diyJ bis (4- (acryJoyJoxybutoxy) -3-methoxybenzoate),

I (3R, 3aR, 6R, 6aR) -hexahydrofuro [3,2-b] furan-3, 6-diyl bis (4- (4 '- (acryJoyJoxybutoxy) benzoyJoxy) -3methoxybenzoate),

I (3R, 3aR, 6R, 6aR) -hexahydrofuro [3,2-b] furan-3,6-diyJ bJs (4- (acryJoyloxy) -2-methyJbenzoate), إ

I (3R, 3aR, 6R, 6aR) -hexahydrofuro [3,2-b] furan-3, 6-diyJ bJs (4- (acryJoyJoxy) -3-methyJbenzoate), ؛

I (3R, 3aR, 6R, 6aR) -hexahydrofuro [3,2-b] furan-3, 6-diyJ bJs (4- (4- (acryJoyJoxy) butoxy) be nzoate),

I (3R, 3aR, 6R, 6aR) -hexahydrofuro [3,2-b] furan-3, 6-diyJ ٠ ؛ bJs (4- (acryJoyJoxy) -3,5-dimethyJbenzoate),

I (3R, 3aR, 6R, 6aR) -hexahydrofuro [3,2-b] furan-3, 6-diyJ bJs (4- (4- (acryJoyJoxy) benzoyJoxy) benzoate), إ le (3R, 3aR, 6R, 6aR) -hexahydrofuro [3,2-b] furan-3,6-diyJ اً bis (4- (4- (4- (acryJoyJoxy) butoxy) benzoyJoxy) benzoate), \

I (3R, 3aR, 6R, 6aR) -hexahydrofuro [3,2-b] furan-3, 6-dJyJ ؛ bJs (4- (4- (4- (acryJoyJoxy) butoxy) benzoyJoxy) -3- ة methoxybenzoate, ج

I (3R, 3aR, 6S, 6aR) -hexahydrofuro (3,2-b] furan-3, 6-dJyJ إ bis (4- (acryJoyJoxyethoxy) benzoate), اً

I (3R, 3aR, 6S, 6aR) -hexahydrofuro [3,2-b] furan-3,6-diyJ إ bis (4- (acryJoyJoxybutoxy) benzoate),

I (3R, 3aR, 6S, 6aR) -hexahydrofuro [3,2-b] furan-3,6-diyJ bJs (4- اً (acryJoyJoxybutoxy) -2-méthyJbenzoate), إ

<img file="MA32259B1_D0014.tif" />

ΜΑ 32259Β1 le (3R, 3aR, 6S, 6aR) -hexahydrofuro [3,2-b] furan-3,6-diyl bis (4- (acryloylo xybutoxy) - 3-methoxybenzoate), (3R, 3aR, 6S, 6aR ) -hexahydrofuro [3,2-b] furan-3,6-diyl ي bis (4- (4 '- (acryloyloxybutoxy) benzoyloxy) -3-' methoxybenzoate), (3R, 3aR, 6S, 6aR) -hexahydrofuro [3,2-b] furan-3,6-diyl bis (4- (acryloyloxy) -2-methylbenzoate), (3R, 3aR, 6S, 6aR) -hexahydrofuro [3,2-b] furan-3, 6-diyl bis (4 (acryloyloxy) -3-methylbenzoate), ؛ the (3R, 3aR, 6S, 6aR) -hexahydrofuro [3,2-b] furan-3,6-diyl ؛ bis (4- (4- (acryloyloxy) butoxy) benzoate), [(3R, 3aR, 6S, 6aR) -hexahydrofuro [3,2-b] furan-3,6-diyl ؛ bis (4- (acryloyloxy) -3,5-dimethylbenzoate), إ le 3R, 3aR, 6S, 6aR) -hexahydrofuro [3,2-b] furan-3,6-diyl bis (4 (4- (acryloyloxy) benzoyloxy) benzoate), ؛ (3R, 3aR, 6S, 6aR) -hexahydrofuro [3,2-b] furan-3,6-diyl bis (4- (4- (4- (acryloyloxy) butoxy) benzoyloxy) benzoate) and ؛ ' (3R, 3aR, 6S, 6aR) -hexahydrofuro [3,2-b] furan-3,6-diyl إ bis (4- (4- (4- (4- (acryloyloxy) butoxy) benzoyloxy) -3- ؛ methoxybenzoate) , and their combinations. ز ι٦

The chiral dopant can be present in the precursor material أ in a range of 0.1% to 25% by weight.

ئ

The marking is preferably applied by inkjet printing, either continuous inkjet type or drop-on-demand inkjet, preferably by single-nozzle / raster printing, or valve-jet . To be applied by inkjet printing, the composition must further contain a solvent in order to adjust its viscosity to the low values ​​required by said printing process. Typical viscosity values ​​for inkjet printing inks range from 4 to 30 mPa.s at 25 ° C. Solvents that can be used

<img file="MA32259B1_D0015.tif" />

ΜΑ 32259Β1 are selected from the group of low viscosity, low polar and aprotic organic solvents such as methyl ethyl ketone (MEK), acetone, ethyl acetate, ethyl 3 ethoxypropionate or toluene. Chlorinated solvents such as dichloromethane, trichloromethane or trichlorethylene are technically suitable, but are not desirable in printing inks because of their toxicity.

The solvent is present in the inkjet precursor material in a range of 10% to 95% by weight, typically 55% to 85%.

In the case of continuous inkjet printing, the precursor material also contains a dissolved conductive agent, typically a salt, such as lithium nitrate, lithium perchlorate, tetrabutylammonium chloride, or tetrabutylammonium tetrafluoroborate.

The salt is present in a concentration range from 0.1% to 5% by weight.

The precursor material may preferably further contain security materials which are present in low or moderate concentrations in order to improve the resistance of the marking to counterfeiting. These security materials are selected from a group comprising inorganic luminescent compounds, organic luminescent compounds, IR absorbers, magnetic materials, forensic markers, and combinations thereof. The concentration ranges are from 0.01% to 5% for luminescent compounds, from 0.1% to 10% for IR absorbers or magnetic materials and from 0.001% to 1% for materials of

<img file="MA32259B1_D0016.tif" />

forensic markers.

The preferred cholesteric liquid crystal precursor material for carrying out the present invention using an inkjet printing apparatus comprises a mixture of at least one nematic compound and at least one chiral inducing compound, an organic solvent and a photoinitiator.

Said nematic compound is preferably of acrylic or bis-acrylic type as disclosed in brevets-Α-0 216 712, ΕΡ-Β-0 847 432 and US-B-6 589 445 which are included here as references. The preferred amount of nematic compound present in the cholesteric liquid crystal precursor mixture is from about 10% by weight to about 60%, preferably from about 10% by weight to about 45%.

Preferred chiral inducers are selected from isosorbide and isomannide derivatives, set forth in ΕΡ-Β-0 739 403, GB-A-2330139 and US-B-6,589,445, which are included herein. as references. The amount of chiral inducer present in the cholesteric liquid crystal precursor mixture is from about 0.1% by weight to about 25%, preferably from about 0.5% by weight to about 15%.

The liquid crystal precursor material for producing a marking according to the present invention may further contain dyes, pigments, coloring agents, diluents, conductive salts, surfactant compounds, surface adhesion promoters, wetting agents, antifoaming agents and agents. of dispersion.

The marking of the present invention is preferably applied in the form of inscriptions representing a code to

32259Β1 bars or a unique one-dimensional matrix code, stacks one-dimensional or two-dimensional. The symbology is preferably selected from the symbols used in the retail industry for the marking of commercial products.

These symbologies are internationally recognized standards and the corresponding reading and decoding algorithms are known and implemented in commercially available devices.

Appropriate one-dimensional and one-dimensional stacked barcode symbologies are known to experts and are available under such symbology names: Plessey,

UPC, Codabar, Code 25 - Non-interleaved 2 of 5, Code 25 Interleaved 2 of 5, Code 39, Code 93, Code 128, Code 128Α,

Code 128Β, Code 128C, Code 11, CPC Binary, DUN 14, EAN 2, EAN 5, EAN 8, EAN 13, GSl-128 (previously known as UCC / EAN128), EAN 128, ucc 128, GSI DataBar previously Reduced Space Symbology (RSS), ITF-14, Pharmacode, PLANET, POSTNET, OneCode,

MSI, PostBar, RM4SCC / KIX, or Telepen.

Appropriate two-dimensional barcode symbologies are known to experts and are available under such symbology names: 3-DI, ArrayTag, Aztec Code,

Small Aztec Code, bCODE, Bullseye, Codablock, Code 1, Code

16Κ, Code 49, Color code, CP Code, DataGlyphs, Datamatrix, Datastrip Code, Dot Code A, EZcode, High Capacity Color Barcode, HueCode, INTACTA.CODE, InterCode, Maxicode, mCode, MiniCode, PDF417, Micro PDF417, PDMark, PaperDisk, Optar, QR Code, Semacode, SmartCode, Snowflake Code, ShotCode,

SuperCode, Trillcode, UltraCode, VeriCode, VSCode, WaterCode, and ECC200- The latter contains a built-in correction code and is defined by an international standard ISO / IEC 16022: 2006.

<img file="MA32259B1_D0017.tif" />

ΜΑ 32259Β1

Types of fonts suitable for optical character recognition (OCR) are known to those skilled in the art. 1 schematically shows a product package having cholesteric liquid crystal labeling of the present invention. The marking is present in the form of Data Matrix code ECC200 on the surface of said packaging. Data Matrix ECC200 is a public domain symbology. The marking can be applied to any location on the packaging. It can therefore be entirely on a first background color (a), or partially, partially covering a first background color and a second color pattern present on the packaging (b) or it can be entirely on a region. white or colorless from the packaging (c).

The reading apparatus for reading the marking of the present invention can be manufactured from barcode readers available on the market, in particular from portable reading apparatus with CCD / CMOS camera and reading stations. used in the retail trade. In the case where there is a good correspondence between the marking and the illumination available (narrow band), said reading apparatus can be made directly capable of reading the liquid crystal codes.

In other cases, the reading apparatus can be modified in order to be able to read the response of specific security elements made in the marking. Accordingly, modified flatbed scanners can also be used. CCD camera barcode scanners are known to experts and are manufactured by several industrial companies like AccuSort, Cognex, DVT, Microscan, Omron, Sick, RVSI, Keyence,

MY

32259Β1 etc.

Said modification of the reading apparatus may include the installation of one or more optical filters chosen from the group comprising linear polarization filters, right circular polarization filters, left circular polarization filters, electro polarization filters. -optics, quarter-wave plates and spectral selectivity color filters of any type and their combinations. In a particular embodiment, at least two different optical filters are used. Said modification may further comprise the installation of one or more particular light sources chosen from the group comprising spectrally selected light sources (i.e. colored), linearly polarized light sources, light sources. left or right circular polarized light and their combinations.

However, the light sources can be selected from ambient light, incandescent light, laser diodes, light emitting diodes and any light sources having color filters. Said light sources may have an emission spectrum in the

<td colspan="2">spectral domain vis</td><td colspan="2">ible (length d</td><td>' wave</td><td>of</td><td>400 to 700 nm).</td>

<td>infrared</td><td>close</td><td>(length</td><td>wave</td><td>of</td><td>Ί</td><td>at 1100 nm).</td>

<td>infrared</td><td>distant</td><td>(length</td><td>wave</td><td colspan="2">from 1100 to</td><td>2500 nm) or uv</td>

<td>(length</td><td>wave</td><td>from 200</td><td>at</td><td> 400</td><td>nm)</td><td>spectrum</td>

<td colspan="2">electromagnetic.</td><td></td><td></td><td></td><td></td><td></td>

Said reading device is therefore not only made capable of reading the marking but also of authenticating it as being made of good security material, that is to say comprising the required security elements. Said reading apparatus provides ./

MA 32259Β1 information and which directs corresponding to digital representative of the code which has been read towards an entry in a database an article bearing said marking and said code.

Said digital information can be compared to information stored in the reading apparatus or can be transferred between the reading apparatus and an external database; the transfer can be carried out in encrypted form using, for example, a public / private RSA type coding. Said information transfer may be effected by any type of transmission means, for example, by wire transmission, wireless radio link, infrared link, etc.

In the particular case where no chiral inducer is included in the precursor material, a nematic liquid crystal polymer is obtained. Such a polymer is generally characterized by birefringence, i.e. the molecules in the printed layer are oriented in a predominant direction and the refractive index component along the molecular axis. is different from the component of the refractive index perpendicular to the molecular axis.

Such a nematic liquid crystal polymer can serve as a security element, thanks to its birefringence properties, in which case it functions as a quarter-wave plate, capable of transforming linear polarization into circular polarization or vice versa for a layer thickness. appropriate. In the case of a reflective substrate, the presence or absence of the applied liquid crystal polymer can therefore be revealed with the aid of a polarization filter.

MY

32259Β1 linear place above the marking in the appropriate orientation. In the case of a substrate which transmits light, either a reflector or a second polarizing filter must be placed behind the substrate to make the marking visible.

In a second embodiment, the marking of the present invention consists of pigment flakes of a liquid crystal polymer; said primer flakes being incorporated into a coating composition applied to the surface of a substrate.

A preferred liquid crystal polymer pigment is of the type described in WO 2008/000755 A1 which is included herein by reference. A marking according to the present invention containing such a pigment has at least two reflection bands in the wavelength range from 200 to 2500 nm.

Cholesteric liquid crystal polymer (CLCP) pigments for carrying out the present invention are disclosed in EP 1 213 338 B1; EP 0 685 749 B1; DE 199 22 158 A1; EP 0 601 483 A1; DE 44 18 490 A1; EP 0 887 398 B1, and WO2006 / 063926. Reference is also made to US Patents 5,211-877, US 5,362,315 and US 6,423,246. Such particles have a thickness of the order of 1 to 10 micrometers and a flake size of the order of 10 to 100 microns and are obtained by fragmenting a corresponding liquid crystal polymer layer. Preferred flakes for use in the present invention have a thickness ranging from 1 to 10 micrometers and an average flake diameter ranging from 20 to 50 micrometers.

Said coating composition contains at least one binder

<img file="MA32259B1_D0018.tif" />

<img file="MA32259B1_D0019.tif" />

32259Β1 as a mandatory component; optionally other pigments, dyes, extenders, additives, photoinitiators, etc. may be present, depending on the needs of the application process and the substrate to be marked. Preferred binders are selected from the group comprising vinyl resins, acrylic resins, maleic styrenehydrous copolymer resins, polyacetal resins, polyester resins, polyester resins modified with fatty acids and UV curable monomers and oligomers, such as acrylates, vinyl ethers, epoxies and mixtures thereof.

Said coating composition may preferably contain other security materials which are present in low or moderate concentrations in order to improve its resistance to counterfeiting. These security materials are selected from a group comprising inorganic luminescent compounds, organic luminescent compounds, IR absorbers, magnetic materials, medicinal markers, and combinations thereof. Typical concentration ranges are 0.01% to 5% for luminescent compounds, 0.1% to 10% for LR absorbers or magnetic materials, and 0.001% to 1% for medical marker materials. .

To meet particular conditions, the coating composition serving to produce a marking according to the present invention may further contain dyes, pigments, coloring agents, diluents, conductive salts, surfactant compounds, surface adhesion promoters, wetting agents. , defoamers and dispersing agents, as is known in the art.

/

ΜΑ 32259Β1

Authentication and identification of the guide crystal marking according to the present invention requires a light source and must be performed in one of the following ways:

i) illuminating the marguage with circularly or linearly polarized light and detecting the reflection of the marking;

ii) by illuminating the marking with unpolarized light (e.g. ambient light) and detecting the reflection ؛ marking through a circularly polarized filter or ؛ linearly; ;

iii) with a combination of illumination in circularly and linearly polarized light إ and detection through a ؛ circular or linear polarization filter. ،

The illumination of a branded article or object is therefore carried out by a light source chosen from unpolarized light sources, linearly polarized light sources, left circular polarized light sources and polarized light sources. circular right.

In all cases, the detection can be carried out with the naked eye إ or using an electro-optical detection device such as ، a photocell or a CCD or CMOS camera. The light sources and detection can be rendered, or be, at ؛ spectral selection using light emitters ؛ particular and / or color filters. The detection is preferably carried out in the visible region (wavelength إ of 400 to 700 nm) of the electromagnetic spectrum. ؛

In a particular embodiment, the illumination of the marking to authenticate an article or an object is carried out using at least two light sources, /

<td colspan="2">different chosen</td><td>among</td><td>of</td><td colspan="2">light sources no</td>

<td>polarized</td><td>(polarized</td><td colspan="2">randomly),</td><td>of</td><td>light sources</td>

<td>polarized</td><td>linearly</td><td>,</td><td colspan="2">sources of</td><td>polarized light</td>

<td>circular</td><td>left and</td><td>of</td><td colspan="2">sources of</td><td>polarized light</td>

<td>circular</td><td>right.</td><td></td><td></td><td></td><td></td>

<td>Fig. 2</td><td>presents</td><td>pictures</td><td>of a</td><td>coded</td><td>Data Matrix ECC200</td>

printed with liquid crystal material on coated cardboard. These images clearly illustrate the advantage of using the polarization properties of labeling with a ؛ liquid crystal material for reading the code printed on a light background - or structure. The most&gt;

advantageous is that of polarized light for the illumination إ and the use of a polarizing filter in front of the camera.

All images were taken with the same light source and with the same camera settings, all in black and white mode, and with or without polarizing filters before the light source and / or the camera. The images have been digitally processed to achieve maximum contrast and optimum brightness.

In a preferred option, the liquid crystal labeling of the present invention is made visible under unpolarized light (preferably ambient light) by passive detection means such as a linear or circular polarized filter. However, the marking can also be identified and authenticated outside the visible spectrum إ (wavelength 400-700 nm), for example in the region إ

Infrared (wavelength 700 to 2500 nm), preferably إ in near infrared (wavelength 700 to 1100 nm), ي in far infrared (wavelength 1100 to 2500 nm) إ or in the UV region (200 to 400 nm) of the electromagnetic إ spectrum, it being understood that the marking has a band

<img file="MA32259B1_D0020.tif" />

ΜΑ 32259Β1 '

أ of reflection in these regions. ؛ l

The liquid crystal polymer is, by its nature, a spectral selectivity reflector whose reflection bands can be adjusted across part of the electromagnetic spectrum by an appropriate choice of its helix pitch. Said pitch depends in particular on the ratio between the nematic precursor material and the chiral inducing compound in the liquid crystal precursor and on the polymerization temperature. After polymerization, the pitch of the helix and therefore the color of reflection of the material remains fixed. [f

ح

As the experts know, small amounts of chiral inducer produce a low hesitancy and thus a large helical pitch. As a result, small amounts of chiral inducer produce a reflection band, in the resulting polymer, on the long wavelength side of the spectrum, typically in the infrared or red region, while large amounts of inducer produce a long wavelength side of the spectrum. Band ; reflection of the resulting polymer on the short wavelength إ side of the spectrum, typically in the blue or UV region. ئ ؛

We must also pay attention to the sense of chirality of, ؛ ! 'Inductor, ie if a predefined inductor gives a ؛;

propeller rotating left or right, which produce ؛ opposite circular polarizations of the reflected light. ؛

Isomannide derivatives are known to produce the reflection of left circular polarized light, while إ isosorbide drifts are known to produce the إ reflection of right circular polarized light.

I

In the following, a typical example of a إ liquid crystal polymer precursor composition is shown:

<img file="MA32259B1_D0021.tif" />

'MY

Cholesteric 32259Β1 which can be applied by continuous inkjet printing process.

MEK 55.7% by weight

4- [4 - [(Ι-οχο-2-propenyl) oxy] butoxycarboxy] 5 2-methyl-1,4-phenylene benzoic acid ester 40.1% by weight

R, 3aR, 6S, 6aR) -hexahydrofuro [3,2-b] furan-3,6-diyl bis (4 (acryloyloxybutoxy) benzoate) 1.70% by weight

Irgacure 907 1.30% by weight

LiC104 1.20% by weight

The following example is a typical cholesteric liquid crystal polymer pigment composition, which can be applied by the valve-jet (drip-on-demand) printing process:

<td>Pioloform®</td><td>BL18</td><td> 5,0</td><td> %</td><td>in</td><td>weight</td>

<td>MEK</td><td></td><td>نيه ة</td><td> %</td><td>in</td><td>weight</td>

<td>Diethylene</td><td>glycol</td><td> 10,0</td><td> %</td><td>in</td><td>weight</td>

<td>Ethanol</td><td></td><td> 8,0</td><td> %</td><td>in</td><td>weight</td>

<td>Pigment</td><td>LC polymer</td><td> 10,0</td><td> %</td><td>in</td><td>weight</td>

<td>Byk®-430</td><td></td><td> 1,5</td><td> %</td><td>in</td><td>weight</td>

<td>Byk®-410</td><td></td><td> 0,9</td><td> %</td><td>in</td><td>weight</td>

Pioloform® BL18 is a polyvinyl butyral resin with CAS RN 63148-65-2 manufactured by Wacker. Byk®-430 is a medium polar polyamide solution of high molecular weight modified urea manufactured by Byk. Byk®-410 is a modified urea solution manufactured by Byk.

The following is another example of a cholesteric liquid crystal polymer precursor composition, which can be applied by the valve-jet printing process:

MEK 83.0% by weight

<img file="MA32259B1_D0022.tif" />

ΜΑ 32259Β1

4- [4 - [(Τοχο-2-propenyl) oxy] butoxy] - 2methyl, 4-phenyiene benzoic acid ester 14.7% by weight (3R, 3aR, 6S, 6aR) -hexahydrofuro [3,2- b] furan-3,6-diyl bis (4 (acryloyloxybutoxy) benzoate) 1.50% by weight

Irgacure 907 0.8% by weight

From the indications and exemplary embodiments present in the foregoing, experts are able to derive other embodiments of the present invention.