OA16616A - Identification and authentication using liquid crystal material markings. - Google Patents

Identification and authentication using liquid crystal material markings. Download PDF

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Publication number
OA16616A
OA16616A OA1201000332 OA16616A OA 16616 A OA16616 A OA 16616A OA 1201000332 OA1201000332 OA 1201000332 OA 16616 A OA16616 A OA 16616A
Authority
OA
OAPI
Prior art keywords
marking
daims
item
code
liquid crystal
Prior art date
Application number
OA1201000332
Inventor
Xavier Marguerettaz
Frédéric Gremaud
Aurélien COMMEUREUC
Vickie Aboutanos
Thomas Tiller
Olivier Rozumek
Original Assignee
Sicpa Holding Sa
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
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Application filed by Sicpa Holding Sa filed Critical Sicpa Holding Sa
Publication of OA16616A publication Critical patent/OA16616A/en

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Abstract

The present invention relates to a marking of polymeric liquid crystal material having determined optical characteristics allowing its authentication and reading by a machine and its authentication by the human eye. The marking is applied onto an item, good or article by a variable information printing process. The marking is in the form of indicia representing a unique code which allows for an easy authentication by the human eye and a secure tracking and tracing of the marked item, good or article throughout its life cycle.

Description

Material Markings
Field of the Invention
The présent invention relates to a machine readable marking for the récognition, identification and authentication of individual J teins. The marking is made of liquid crystal material, which is app.lied to a substrate by known variable information printing techniques. The marking is détectable and/or identifiable by passive detecting means, e.g. optical filters under unpolarized (ambient) light, as well. as by illumination with polarized light. The marking is applied in the form of indicia, such as a one- or two-dimensional bar code, a matrix code, or the like.
Background of the Invention
Track and Trace Systems are current.l.y used in different fields of industry. Many industries su f i er from counterfelt or diverted products, in particular in the field of mass-produced items such as beverages, perfumes, pharmaceutical drugs, cigarettes, CDs/DVDs, as well as other ki.nd of consumables.
Counterfeiting and market diversion are f acil.itated if the mass products are handled on a lot base, rather than on an individual. item base. Counterfeit or diverted products are in such case easi.ly introduced into the supply chain. Producers and retailer.s would like to be i.n a position to distinguish their original products from such counterfeit or diverted (parai le I. imported) products at the level oï: the individual unit which can be so.ld.
The underlying technica l probl.em has boen addressed in the art through an individual marking of each sell.abie item introduced into t:he supply chain. The markings of the pri.or art were
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chosen in such a way that they were not susceptible toJ » photocopying, i.e. preferably covert markings were used, whichi are not visible to the unaided eye or the photocopying» machine.i ri i A Covert marking, in the context of the présent invention,J is any marking or seçurity element, which cannot bet
I authent.icated by the unaided eye, but which, for' t
authentication, dépends on a detecting or reading device of J 1
any kind, such as ah optical filter or an electronic
authentication eguipment. >
An Overt marking, in the context of the présent invention, f » « i
is any marking or seçurity element. which, for authentication, 1
does not dépend on a detecting or reading device; i.e. which <
can be authenticated by the unaided eye.
Color in the context of the présent invention is used to, designate any spectrally sélective return of light (electromagnetic radiation) from an illuminated object, be it *’ in the visible, the infrared or in the UV range of theî » electromagnetic spectrum (i.e. in the whole wavelength rangei from 200nm to 2500nm).
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The term visible is used to indicate that a property can be , revealed by the unaided eye; détectable is used for a’ property that can be revealed by an optical instrument, though’ not necessarily by the unaided eye, and invisible is used» for a property that cannot be detected by the unaided eye. In
K partîcular, the term visible color means a spectrally * t sélective return of light in the wavelength range from 400nm;
to 700nm, which is détectable bÿ the unaided eye.
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A first type of individual markings, useful to prevent counterfeit and diversion, is disclosed in US 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 onto the item, using an ink which is not détectable under light of the visible spectrum (400-700nm wavelength) but which becomes visible when illuminated with light of the UV spectrum (200-380nm wavelength).
A second type of individual markings is disclosed in US 5,611,958 and US 5,766,324. According to these documents, a marking is applied onto a commercial good, using an ink which is not détectable in the visible spectrum, but which can be detected through illumination with light of the infrared spectrum (800-1600nm wavelength).
Yet; another type of individual markings, applied through an ink, is disclosed in US 5,360,628 and US 6,612,494. This marking needs to be illuminated jointly with UV- and IR-light to be revealed.
Still another type of individual marking relies on inks comprising up-converting phosphors such as described in US 5, 698,397.
Ail of the markings mentioned in the cited prior art are covert markings, which are completely invisible to the unaided human eye. The reading of such covert markings dépends on a corresponding detecting or reading device, able to detect or read the marking. This can be a disadvantage at the retail center or at the po.int-of-sale, where an appropriate reading device may not always be available.
Overt markings comprising optically variable features, e.g.
exhibiting viewing-angle dépendent color, hâve been proposed
in the art as authentication means for the person in the
street. Among these are the holograms (cf. Rudolf L. van
Renesse, Optical Document Security 2nd ed., 1998, chapter
10), the optical thin film security devices (idem, chapter 13) and the liquid crystal security devices (idem, chapter 14).
Particularly useful as security devices are the cholesteric liquid crystals. When illuminated with white light, the cholesteric liquid crystal structure reflects light of a determined color, which dépends on the material in question and generally varies with the angle of observation and the device température. The cholesteric material itself is colorless and the observed color is only due to a physical. reflection effect at the cholesteric helical structure adopted at a g.iven température by the liquid crystal material. (cf. J.L Fergason, Molecular Crystals, Vol. 1, pp. 293-307 (1966)). In particular liquid crystal materials, the cholesteric liquid crystal polymers (CLCPs), the cholesteric helical structure is frozen in a determined state through polymerization, and thus rendered temperature-independent.
If the cholesteric liquid crystal material is applied on a dark or black background, its reflection color is highly apparent to the unaided eye, because the light transmitted by the cholesteric material is largely absorbed by the background, so that the residual backscattering from the background does not disturb the perception of the cholesteric material's own reflection. A careful choice of the background color can thus contribute tô the visibility of such an overt marking.
On a clear or white background the reflection color of the cholesteric liquid crystal material is virtually invisible due to the superposition of the cholesteric material's own reflection with the strong backscattering from the background. The cholesteric liquid crystal material can, however, always be identified with the help of a circular polarization filter because it selectively reflects only one of the two possible circular polarized light components, in accordance with its chiral helical structure.
EP-B1-1 381 520 and EP-A1-1 681 586 refer to a biréfringent marking and a method of applying the same in the form of a liquid crystal layer having a non-uniform pattern of régions of different thickness. The applied liquid crystal coating or layer may provide for a hidden image on a reflective substrate, which is invisible when viewed under unpolarized light but rendered visible under polarized light or with the help of a polarization filter.
US 5,678,863 refers to means for the identification of documents of value which include a paper or polymer région, said région having a transparent and translucent characteristic. A liquid crystal material is applied to the région to produce an optical effect, which differs when viewed in transmitted and reflected light. The liquid crystal material is in liquid form at room température and must be enclosed in a containing means such as microcapsules, in order to be used in a printing process such as gravure, roller, spray or ink-jet printing. The printed liquid crystal région can be in the form of a pattern, for example a bar code. The pattern can be verified by Visual or machine inspection of the polarization states of the areas having left-handed and righthanded liquid crystal forms.
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US 5,798,147 refers to coating compositions of polymerizable liqu.id crystaJ. monomers which can be applied by conventional printing processes, such as letterpress, rotogravure, flexographic, offset, screen, and ink-jet printing. The printing inks can be used to produce markings and security inscriptions which are invisible to the human eye. The markings can be detected by their ci.rcular polarization or their angle dépendent reflection color.
US 6,899,824 refers to a process for printing or coating a substrate with a multilayer of a liquid-crystalline composition and at least one non-liquid-crystalline coating. The process and the printed substrate are useful for producing a counterfeit-proof marking of articles. Preferred methods for applying such printing or coating are screen printing, planographic printing, flexograhic, and letterpress printing.
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None of the markings disclosed in the prior art does, however, provide a solution to the technical problem underlying track & trace applications, wherein, in addition to a machinereadable individual coding of items with a counterfeitresistant security marking, an easy authentication of the marking by the una.ided eye is required.
Track & Trace applications are known in the art for e.g., postal services, wherein each mail piece is individually marked and followed throughout its delivery chain. Barcodes,
such as lD-barcodes, stacked 10-barcodes, 2D-barcodes or
matrix-codes, are most often used as the marking and
identification means.
No particular effort is devoted to authentication aspects in
the case of the said postal markings, given that the mail piece is handled service-internally by the mailing company throughout the entire . delivery chain, so that no authentication is needed. Postal Track & Trace applications are merely focused on the identification of the mail piece.
Authentication aspects are, however, of crucial importance in retail applications, where there is a potential risk of substitution of the original goods by counterfeit or diverted ones. For this reason, Track & Trace applications in this field must be combined with at least one security element, able to certify the authenticity of the marked good as an original one.
In the following, Secure Track & Trace means the combination of a Track & Trace application, which allows for the identification of an individual item, with at least one security element, which additionaLly allows for the authentication of the said item as being genuine.
Technical problem
For Secure Track & Trace applications, where a good in open circulation must be marked individually as to its authenticity and identity, and followed throughout its life cycle or for a spécifie përiod of time, e.g. for liability reasons, there is a need for a marking which is i) uniquely coded, so as to be identifiable ii) machine-readable, iii) copy (counterfeit) résistant, iv) authenticate-ab.le by eye by a human user, and v) authenticate-able by a machine. For particular applications it is furthermore désirable that part of the marking is invisible to the unaided human eye.
Summary of the Invention the case of the said postal markings, given that the mail piece is handled service-internally by the mailing company throughout the entire delivery chain, so that no authentication is needed. Postal Track & Trace applications are merely focused on the identification of the mail piece.
Authentication aspects are, however, of crucial importance in retail applications, where there is a potentiel risk of substitution of the original goods by counterfeit or diverted ohes. For this reason, Track & Trace applications in this field must be combined with at least one security element, able to certify the authenticity of the marked good as an original one.
In the following, Secure Track & Trace means the combination of a Track & Trace application, which allows for the identification of an individual item, with at least. one security element, which additionally allows for the authentication of the said item as being genuine.
Technical problem
For Secure Track & Trace applications, where a good in open circulation must be marked individually as to its authenticity and identity, and followed throughout its life cycle or for a spécifie period of time, e.g. for liability reasons, there is . a need for a marking which is i) uniquely coded, so as to be identifiable ii) machine-readab.l.e, iii) copy (counterfeit) résistant, iv) authenticate-able by eye by a human user, and v) authenticate-able by a machine. For particular applications it is furthermore désirable that part of the marking is invisible to the unaided human eye.
Summary of the Invention
The marking of the présent invention, for the secure tracking or tracing of an item or article, comprises a polymeric liquid crystal material having determined optical characteristics, which allow for its authentication and reading by a machine, as well as its authentication by the human eye. The marking is produced on a substrate by a variable information printing process in the form of indicia representing a unique code, which allows for .its identification. The marking is further preferably laid out such that part of it is invisible to the unaided human eye.
The marking of the présent invention is applied on items or articles such as value documents, banknotes, passports, identity documents, driving licenses, official permissions, access documents, stamps, tax stamps and banderoles, transportation tickets, event tickets, packaging, spare parts, and consumer goods, the marking, either directly - applied indirectly - applied to a label labels, foils, which thus carry to their surface - or applied to their surface.
The polymeric liquid crystal material is preferably of the cholesteric (i.e. twisted nematic) type; for certain applications, nematic (biréfringent) liquid crystal material may also be used.
The polymeric liquid crystal material of the marking can either be présent as a liquid crystal material polymerized on the surface of a substrate, or alternatively consist of pigment flakes of a liquid crystal. polymer, comprised in a coating composition applied on a substrate.
Said substrate can be any type of substrate, woven or nonwoven, in particular it can be paper, cardboard, wood, glass, ceramic, métal, plastic, textile, leather, etc.; the substrate may be coated or uncoated, or comprise a sealed or a nonsealed surface.
The polymer.ic liquid crystal material of the marking preferably comprises further security materials, which are présent to increase its résistance towards counterfeiting. These security materials are selected from the group consisting of the inorganic luminescent compounds, the organic luminescent compounds, the IR-absorbers, the magnetic materials, the forensic markers, and combinations thereof.
Said security material can be présent as a mere admixture, or, according to the nature of the security material, also as a co-polymerized component of the liquid crystal pigment, of the liquid crystal precursor composition, or of the ink binder. In particular, organic security materials comprising an acrylic or vinylic functionality are easily co-polymerized into a corresponding main polymer. Alternatively, the security « material may be grafted, i.e. chemically linked, onto a preexisting polymer chain.
The substrate, representing the background on which the liquid crystal material is applied, can be of any color; a white background being a preferred option for realizing a marking ' which is invisible to the. unaided eye in the sense that no visible color is observed. A metallic reflecting background is a further prefebred option, in particular in the case of a nematic (biréfringent) liquid crystal material. The substrate may in general be selected from the group consisting of * reflecting substrates, colored substrates, and transparent substrates.
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For enabling an easy authentication by a human user, it is preferred that at least part of the background on which the liquid crystal material is applied has a contrasting color, . such as red, green, blue or black, which, in combination with 5 the liquid crystal marking, allows to perceive a visible color and an angle-dependent color change by the unaided eye.
Said substrate is thus preferably a patterned substrate, f
comprising at least two different.Ly colored surface areas, each selected from the group of white surface areas, black surface areas, visibly colored surface areas, reflecting surface areas, transparent surface areas and combinations thereof. It is thus évident to the skilled in the art that the substrate surface carrying the liquid crystal material can hâve two or more colored areas underneath the liquid crystal material.
The substrate surface, on which the liquid crystal material is applied, can furthermore carry indicia, which may be of any « 20 form or color, such as a pattern., an image, a logo, a text, a
ID- or 2D-barcode or a matrix code, etc. The said indicia can be applied by any method of printing or coating.
The substrate can furthermore carry at least one security «
element selected from the group of inorganic luminescent compounds, organic luminescent compounds, IR-absorbers, magnetic materials, and forensic markers or combinations thereof. The security element can be présent in the form of indicia on the substrate surface or be incorporated (embedded) 30 in the substrate itself.
The polymeric liquid crystal material is-preferably présent in the form of indicia, such as a text or a code. Preferred
- - Il indicia are chosen from the group comprising 1-dimensional, stacked 1-dimensional, and 2-dimensional barcodes. Current barcode symbologies hâve been disclosed by Bob Williams in Understanding Barcoding, Pira International Ltd., 2004 (ISBN 1 85802 917 1)
The liquid crystal marking of the présent invention is preferably produced by applying a liquid crystal precursor composition to a substrate and hardening the composition in ' the ordered liquid crystal state. The said precursor composition comprises reactive monomers or oligomers of at least one nematic liquid crystal compound. The reactive monomers or oligomers are preferably UV-cure-able; in this case the applied composition is UV-cured and also comprises a photoinitiator System, as known to the skilled person.
The ordered liquid crystal state dépends upon the presence of a chiral dopant. Nematic liquid crystals without chiral dopant arrange in a molecular texture which is characterized by its biréfringence. Nematic precursors are known from EP-A-0 216 712, EP-B-0 847 432, and US-B-6,589,445.
For producing a cholesteric (i.e. twisted nematic) liquid crystal polymer, the said precursor composition must also comprise a chiral dopant. Said dopant may be chosen from the dérivatives of isosorbides and isomannides and mixtures thereof; as known from EP-B-0 847 432, GB-A-2 330 139, and USB 6,589,445. Isosorbides are known to induce a right helical twist, whereas isomannides are known to induce a left helical twist. ,
Said dopant induces a helical structure in the nematic liquid crystal compound, characterized by a helical pitch of the e’ 'i . < -*.·»· ti’r. i c* Μ (ΜίΛίί'ίι..**-»ir. *4 .Tt »..Γ. IU <
ii order of the wavelength of visible light, leading to light reflection at determined wavelengths, and hence to the appearance of interférence color, as well as of angledépendent color shift. The reflected light from cholesteric 5 liquid crystal phases is circularly polarized (either lefthanded or right-handed), according to the rotation sense of the cholesteric helical twist.
The marking of the présent invention is produced by applying 10 the liquid crystal precursor composition to a substrate and subsequently hardening the said composition on the substrate. The hardening is preferably performed by subjecting the applied composition to irradiation with UV-light, which induces a polymerization of the reactive monomers or oligomers 15 to form a liquid crystal polymer. The molecular ordering of the liquid crystal is thereby retained, i.e. the nematic or cholesteric texture is fixed in the state which was présent during the irradiation. In the case of cholesteric liquid crystal material, the helical pitch, and herewith the optical 20 properties, such as the reflection color and the angledependent color shift remain thus fixed.
A method for marking an item or article comprises thus the steps of providirig a suitable item or article to be marked, 25 and applying at least one polymeric liquid crystal material in * the form of .indicia representing a unique code by a variable information printing process onto the said item or article. In particular, the unique code represented by the said indicia may be an encrypted information, and the method may comprise 30 the step of encrypting the said information.
The said liquid crystal precursor composition can be applied to a substrate by any coating or printing technique.
Preferably the composition is applied by a variable information printing process, such as laser printing or inkjet printing of the continuous or of the drop-on-demand type. , Said variable information printing method allows for the unique coding of the marking for each printed item.
For application by laser printing the liquid crystal polymer pigment flakes can be incorporated into a toner composition. To this aim, the liquid crystal polymer pigment particles are added in a ratio ranging from 1 wt% to 50 wt% to a toner composition comprising a binder resin and optionally, additives such as, charge control agents or waxes.
Said binder resin présent in a ratio ranging from 45 wt% to 95 wt%, is composed of thermoplastic polymers such as polyamides, polyolefines, polyuréthanes, vinyl resins, epoxides, styrene butadiene, styrene acrylate copolymers or polyester resins, and has a glass transitions température Tg in the range of 40°C to 120°C, preferably 60°C to 70°C, and an average polymer , particle size lying in the range of 2-30pm depending on the desired resolution of the printed image. The liquid crystal polymer pigment flakes may be encapsulated in said binder resin.
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Optionally, the liquid crystal polymer pigment flakes, incorporated in a toner composition as described above, can be added to a liquid carrier in a ratio ranging from 5 wt% to 60 wt%, thus forming a liquid developer, which can then be used as a liquid toner, as known to the skilled person. Preferred liquid carriers are aliphatic hydrocarbons, alicyclic ' hydrocarbons or polysiloxanes. Amongst them, paraffin solvents and isoparaffin solvents are preferred.
For application by ink-jet printing, the composition also comprises an organic solvent, in order to adjust the viscosity value of the composition to be compatible with the chosen printing process, as known to the skilled person.
For application by continuous ink-jet printing, the composition also comprises a conducting agent (sait), which must be soluble in thé composition used. Such conducting agent , is needed as technical requirement of this printing process, as known to the skilled person.
In an alternative embodiment, the liquid crystal marking of the présent invention is produced by applying to a substrate a « coating composition comprising liquid crystal polymer pigment flakes in a suitable binder.
The said liquid crystal pigment polymer flakes are preferably of cholesteric liquid crystal polymer, exhibiting light reflection at determined wavelengths (interférence color), as well as angle-dependent color shift. Such pigments are known to the skilled person from WO 2008/000755 Al (and related documents), EP 1 213 338 Bl; EP 0 685 749 Bl; DE 199 22 158 Al; EP 0 601 483 Al; DE 44 18 490 Al; EP 0 887 398 Bl, W02006/063926, US 5,211,877, US 5,362,315, and US 6,423,246.
Suitable binders can be Chosen from the vinylic resins, acrylic resins, styrene-maleic anhydride copolymer resins, polyacetal resins, polyester resins, fatty acid modified polyester resins and the mixtures thereof. The binder may further be chosen from the UV curing monomers and oligomers, such as acrylates, vinyl ethers, epoxides and combinations thereof.
The marking is preferably applied by ink-jet printing. For a reliable printing and acceptable print quality, the ink-jet equipment used must hâve a sufficiently large orifice (nozzle) diameter. The nozzle diameter should be at Ieast 10 times the mean diameter of the liquid crystal pigment polymer flakes. For example, for a mean flake diameter of 25 μιη the nozzle diameter should be at Ieast 250 pm. Systems providing said characteristics are valve-jet printers, a particular form of drop-on-demand ink-jet printers.
In general, the method for authenticating an item or article carrying a marking according to the présent invention comprises the steps of a) providing an item or article carrying a marking according to the présent invention, b) illuminating the marking on said item or article with at Ieast one quality of light from at Ieast one light source, c) detecting the said marking's optical characteristics through the sensing of light reflected by the marking, d) determining the item's or article's authenticity from the detected optical characteristics of the marking.
The marking of the présent invention can be authenticated according to a first method by simple visual inspection under ambient light. To this aim, the background, on which the liquid crystal material is applied, must provide sufficient optical contrast, so as to allow the human observer to perceive the reflected color and the color shift of the liquid crystal material. Depending on the background, part of the marking may remain vi rtual.ly invi sible to the unaided eye.
In a second method, the marking is authenticated under ambient light with the help of a passive detecting means such as an optical filter. A preferred such passive detecting means is a left-handed or a right-handed circular polarizing filter, or a juxtaposition of both. This allows determining the rotation sense of the helical pitch of the cholesteric liquid crystal material by determining the polarization state of the light reflected by the said material. Optionally, the polarization filter can be combined with color filters, in order to reduce the spectral bandwidth to the spectral reflection band of the liquid crystal material, and hence to reduce background contributions. More than one optical filter may be used in conj unction.
Ih a third method, the marking is authenticated with the help of circular polarized light from at least one polarized light source. The liquid crystal material refleçts differently light of different circular polarization; hence materials of left and of right helical pitch can be distinguished by their respective response to circularly polarized light. The illumination of the marking by the polarized light source, as well as the observation of the reflected light from the marking, may optionally be performed through a color filter. More than one polarized light sources may be used in conjunction.
In a fourth method, the marking is authenticated with the help of an electro-optical authentication device. In a first embodiment, said device comprises at least one photocell, in combination with a circular polarization filter and/or with a circular polarized light source. In another embodiment said device comprises an electro-optic caméra, such as a linear CCD ’ sensor array, a 2-dimensional CCD image sensor array, a linear CMOS image sensor array, or a 2-dimensiona.l CMOS image sensor array, in combination with a circular polarization filter and/or with a circular polarized light source.
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Optionally, the circular polarization filter or the circular polarized light. source in the above embodiments can be combined with côlor filters, to select a particular spectral domain and to enhance the contrast ratio of the light reflected from the liquid crystal material to the light reflected from the background.
The circular polarization filters can generally also be replaced by an electro-optic polarization switch. Such device is known in the art, e.g. from DE 102 11 310 B4, and allows to select one or the other circular polarization state by an applied corresponding voltage.
In ail cases of cholesteric liquid crystal materials, the marking of the présent invention is authenticated by verifying one or more of its characteristic properties, namely the circular polarization state and/or the viewing-angle dépendent color of the reflected light from the marking. The polarized light source or the polarized light détection equipment or both may be chosen to operate in the visible, the infrared, or the UV région of the electromagnetic spectrum, or in a combination of these, according to the optical characteristics of the marking.
The marking of the présent invention can be identified by reading the indicia . it represents and by subsequently correlating the information so retrieved from the marking with information stored in a data base. In a particular embodiment, the information represented by the indicia of the marking is encrypted, and said identification comprises the step of decrypting said information. Preferably, the indicia are read by an electro-optic caméra, such as a CCD- or a CMOS-image r· sensor array.
In general, the method for ident.ifying an item or article carrying a marking according to the présent invention comprises the steps of a) providing an item or article carrying a marking according to the présent invention, b) illuminating the marking on said item or article with at least . one quality of light from at least one light source, c) reading the indicia represented by the marking, deriving corresponding information, d) correlating the information retrieved from the indicia of the marking with information stored in a data base, e) obtaining confirmation or déniai concerning the item's or articles identity.
The identification of an item or article carrying a marking according to the présent invention can be performed with the same reading equipment configuration or assembly which is used for the authentication.
In a first embodiment the said indicia are represented by a 1dimensional or a 2-dimensional barcode, and the image retrieved by the electro-optic caméra in digital form is analÿzed using a corresponding algorithm. The information contained in the barcode is retrieved, if necessary, decrypted, and compared with information stored in a data base, hereby identifying the item, and optionally updating the data base with supplementary information, e.g. about the item's history. The caméra may be part of a reading device equipped with own communication capabilities, or part of a communication device, such as a mobile phone, the retrieval of the information taking place using the mobile phone's internai resources. The data base may be either located in the communication device (built-in or exchangeable memory) , or on an external server reached via a communication network.
In a second embodiment the said indicia are represented by an alphanumeric code, and the image retrieved by the electrooptic caméra (reading device) in digital form is analyzed using a corresponding optical character récognition (OCR) · algorithm. The information contained in the code is retrieved and compared with information stored in a data base, hereby identifying the item, and optionally updating the data base. As in the first embodiment, the data base may be either located in the reading device (built-in or exchangeable « memory), or on an external server reached via a communication network. The alphanumeric code can be printed using a standard font or a spécial machine identifiable font. Alternatively, the alphanumeric code can be visually read and either sent via a communication System (e.g. Internet or SMS) to a data center for validation or checked against data provided with the item ' in form of a label, reference mark or another alphanumeric code.
The marking of the présent invention, made of polymeric liquid crystal material having determined optical characteristics, can be used for -the secure tracking and tracing of items, articles or goods with an individualized, counterfeitresistant code for the secure tracking and tracing of said items, articles or goods.
The application of an individualized code onto a good or item requires a variable information printing process. A preferred variable information printing process in the context of the présent invention is chosen from the group of continuous inkjet printing and drop-on-demand ink-jet printing; these printing processes allow for a rapid, non-contact application of said individualized code onto any kind of surfaces. Said individualized code allows the identification of each single item at a later stage of its life cycle.
In order to prevent the substitution of the original item by a counterfeit carrying a copy of said individualized code, said individualized code must be counterfeit-resistant. Counterfeit résistance can be provided through a particular security material having particular physical, preferably optical, properties; the said material can be either constitutive or incorporated in the marking. The particular security material can be a polymeric liquid crystal material having determined optical characteristics, or an additive selected from the group of the inorganic luminescent compounds, the organic luminescent compounds, the IR-absorbers, the magnetic materials, the forensic markers, and combinations thereof.
The marking of the présent invention can be used on items or articles, such as value documents, banknotes, passports, identity documents, driving licenses, official permissions, access documents, stamps, tax stamps and banderoles (in , particular for tobacco products and alcoholic beverages), transportation tickets, event tickets, labels, foils, packaging (in particular for pharmaceutical products), and in general for marking spare parts and consumer goods (in particular to address liability issues).
The marking of the présent invention, applied to items, goods, or articles is suitable for use in the secure tracking and tracing of such marked items, goods or articles. Such secure tracking and tracing of an item or article comprises noteworthy the first commutable steps of a) applying a marking according to the invention to the item or article to be «
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f traced; and b) storing information related to the marked item or article in a data base; as well as the second commutable steps of c) authent.icating the item or article according to the authentication method disclosed herein; and d) identifying the item or article, according to the identification method disclosed herein, using the information previously stored in the data base. Optionally the data base may hereby be updated with new information éléments related to the item or article.
The code applied to the item or good représente digital information, which is stored in a data base, in order to identify the item or good at a later stage. Said code may be encrypted, so as to protect the information it contains upon transmission from and to the data base. Said data base can be part of a data base management system. Ail kind of encryption algorithme are suitable, e.g. a public-private key of the RSA type.
Said data base may be a local, data base, integrated into the authentication device. Alternative!y, it may be a remote data * base, linked to the authentication device through a wired or wireless connection. A local data base may also be updated regularly from a remote server.
In a further aspect, the présent invention provides for the application of the individual marking by a variableinformation printing process. Preferred is ink-jet printing, either using the continuous ink-jet, or the drop-on-demand (DOD) ink-jet or valve-jet printing process. Industrial inkjet printers, commonly used for numbering and coding applications on cond.itioning .Unes and printing presses, are particularly suitable. Preferred ink-jet printers are single nozz.le continuous ink-jet printers (also called raster or multi level deflected printers) and drop-on-demand ink-jet, in particular valve-jet, printers.
To provide for an entirely covert and machine readable marking, nematic liquid crystal materials are used. To provide for an overt or semi-covert and machine readable marking, cholesteric or chiral-nematic liquid crystal materials are used.
Description of the Drawings
For a more complété understanding of the présent invention reference is made to the detailed description of the invention and the attached drawings.
Fig.l schematically depicts a cardboard packaging, e.g. a pharmaceutical packaging, carrying représentative markings a),
b) , c) according to the invention, which are printed with liquid crystal material at different locations on said cardboard packaging:
a) shows a Data Matrix code on a particularly dark colored background, e.g. a black background;
b) shows a Data Matrix code on a background of mixed color, e.g. having dark and 1jght colored parts;
c) shows a Data Matrix code on a white background.
Fig. 2 shows images captured from an ECC200 data matrix code printed with UV-cured liquid crystal (LC) material on coated cardboard:
a) LC Data Matrix code retrieved from a black background, under right-circular polarized white light illumination, having a right-circular polarizing filter in front of the CMOS caméra.
b) LC Data Matrix code retrieved from a black/white background, under right-circular polarized white light illumination, having a right-circular polarizing filter in front of the CMOS caméra.
c) LC Data Matrix code retri eved from a black/white background, under right-circular polarized white light illumination, having no filter in front of the CMOS caméra.
d) LC Data Matrix code retrieved from a black/white background, under unpolarized white light illumination, having no filter in front of the CMOS caméra.
DetaJ-led. Description of the Invention
In a first embodiment, the marking of the présent invention is made of a liquid crystal precursor material, which is applied in a liquid state to the surface of a substrate, and thereupon polymerized (cured) in the ordered liquid crystal state by irradiation with UV light or with électron beam radiation, as known by the skilled in the art.
The liquid crystal material applied in this embodiment is thus 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 are from the' group of bisacrylates such as benzoic acid 4-[4-[(l-oxo-2-propenyl)oxy] butoxy]~l,4phenylene ester, benzoic acid 4-[4-[(l-oxo-2-propenyl)oxy] butoxy]-, 2methyl-1,4-phenylene ester, benzoic acid- - 4-[4-[ (l-oxo-2-propenyl)oxy] hexoxy]-, 2methyl-1,4-phenylene ester, benzoic acid 4-[4-[ (l-oxo-2-propenyl)oxy] butoxycarboxy]1,4-phenylene ester, benzoic acid 4-[4-[(l-oxo-2-propenyl)oxy] butoxycarboxy]-, 2-methyl-l,4-phenylene ester, and the combinations thereof.
The nematic liquid crystal monomer or oligomer may be présent in the precursor material in a range of 10% to 100% by weight.
In case the curing is performed by UV radiation, the precursor material comprises at least one photoinitiator system comprising at least one photoinitiator and optionally a stabilizer. Suitable photoinitators can be chosen from the group of Irgacure (e.g. Irgacure 369, 651, 907 or 1300),
Genomer (e.g. BP/EPD) or other free radical inducers.
Suitable stabilizers are Florstab UV-1 supplied by Kromachem, and Genorad 16 supplied by Rahn.
The photoinitiator may be présent in the precursor material in a range of 0.5% to 5% by weight.
For obtaining cholesteric (i.e. twisted nematic) phases, said precursor further comprises at least one chiral dopant (chiral inducer). Suitable chiral dopants comprise the dérivatives of isomannide and of isosorbide, such as (3R, 3aR,6R,6aR)-hexahydrofuro[3, 2-b]furan-3,6-diyl bis(4(acryloyloxyethoxy)benzoate) , (3R, 3aR, 6R,6aR)-hexahydrofuro[3,2-b]furan-3,6-diyl bis(4(acryloyloxybutoxy)benzoate), (3R, 3aR, 6R,6aR)-hexahydrofuro[3,2-b]furan-3,6-diyl bis(4(acryloyloxybutoxy)-2-methylbenzoate), (3R, 3aR, 6R,6aR)-hexahydrofuro[3,2-b]furan-3,6-diyl bis(4(acryloyloxybutoxy)-3-methoxybenzoate), (3R, 3aR, 6R,6aR)-hexahydrofuro[3,2-b]furan-3,6-diyl bis(416616 ¢4' -(acryloyloxybutoxy)benzoyloxy)-3-methoxybenzoate), (3R, 3aR,6R,6aR)-hexahydrofuro[3, 2-b]furan-3,6-diyl bis(4(acryloyloxy)-2-methylbenzoate) , (3R, 3aR, 6R,6aR)-hexahydrofuro[3, 2-b]furan-3,6-diyl bis(4(acryloyloxy)-3-methylbenzoate) , (3R,3aR,6R,6aR)-hexahydrofuro[3,2-b]furan-3,6-diyl bis(4(4-(acryloyloxy)butoxy)benzoate) , (3R, 3aR, 6R, 6aR) -hexahydrofuro [3,2-b] furan-3, 6-diyl bis (4(acryloyloxy)-3,5-dimethylbenzoate) , (3R, 3aR, 6R,6aR)-hexahydrofuro[3,2-b]furan-3,6-diyl bis (4(4-(acryloyloxy)benzoyloxy)benzoate) , (3R, 3aR, 6R,6aR)-hexahydrofuro[3,2-bJfuran-3,6-diyl bis(4(4-(4-(acryloyloxy)butoxy)benzoyloxy)benzoate), (3R,3aR,6R,6aR)-hexahydrofuro[3,2-b]furan-3,6-diyl bis(4(4-(4-(acryloyloxy)butoxy)benzoyloxy)-3-methoxybenzoate, (3R, 3aR, 6S,6aR)-hexahydrofuro[3, 2-b]furan-3,6-diyl bis(4(acryloyloxyethoxy)benzoate) , (3R, 3aR, 6S,6aR)-hexahydrofuro[3, 2-b]furan-3,6-diyl bis(4(acryloyloxybutoxy)benzoate), (3R, 3aR, 6S,6aR)-hexahydrofuro[3, 2-b]furan-3,6-diyl bis(4(acryloyloxybutoxy)-2-methylbenzoate), (3R, 3aR, 6S, 6aR)-hexahydrofuro[3, 2-b]furan-3,6-diyl bis(4(acryloyloxybutoxy)-3-methoxybenzoate), (3R, 3aR, 6S,6aR)-hexahydrofuro[3, 2-b]furan-3,6-diyl 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) , (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), (3R, 3aR,6S,6aR)-hexahydrofuro[3,2-b]furan-3,6-diyl bis(4(4-(acryioyloxy)benzoyloxy)benzoate), (3R, 3aR,63,6aR)-hexahydrofuro[3, 2-b] furan-3,6-diyl bis (4(4-(4-(acryioyloxy)butoxy)benzoyloxy)benzoate) and (3R, 3aR, 6S,6aR)-hexahydrofuro[3,2-b]furan-3,6-diyl bis(4(4-(4-(acryioyloxy)butoxy)benzoyloxy)-3-methoxybenzoate) , and combinations thereof.
The chiral dopant may be présent in the precursor material in a range of 0.1% to .25% by weight.
The marking is preferably applied by ink-jet printing, either of the continuous ink-jet or of the drop-on-demand ink-jet type, preferably by single nozzle/ raster or by valve-jet printing. For application by ink-jet printing, the composition must further contain a solvent, in order to adjust its viscosity to the low values required by the said printing processes. Typical viscosity values for ink-jet printing inks are in the range of 4 to 30 mPa.s at 25°C. Solvents, which can be used are chosen from the group of the low-vi.scosity, slightly polar and .aprotic organic solvents, such as methylethyl-ketone (MEK), acetone, ethylacetate, ethyl 3ethoxypropionate or toluene. Chlorinated solvents like dichloromethane, trichloromethane or trichloroethylene are technically suitable, but not désirable in printing inks because of their toxicity.
The solvent is comprised in the ink-jet precursor material in a range of 10% to 95%, typically 55% to 85% by weight.
In the case of continuous ink-jet printing, the precursor material also comprises a dissolved conducting agent, typically a sait, such as lithium nitrate, lithium perchlorate, tetrabutylammonium chloride or tetrabutylammonium tetrafluoroborate.
The sait is présent in a concentration range of 0.1 to 5% by weight.
The precursor material preferably may further comprise security materials, which are présent in low to moderate concentration, in order to increase the résistance of the marking towards counterfeiting. These security materials are selected from the group consisting of the inorganic luminescent compounds, the organic luminescent compounds, the IR-absorbers, the magnetic materials, the forensic markers, and combinations thereof. Concentration ranges are 0.01% to 5% for luminescent compounds, 0.1% to 10% for IR-absorbers or magnetic materials, and 0.001% to 1% for forensic marker materials.
The preferred cholesteric liquid crystal precursor material for carrying out the présent invention using ink-jet printing equipment comprises a mixture of at least one nematic compound, at least one chiral inducer compound, an organic solvent, and a photoinitiator.
Said nematic compound is preferably of the acrylic- or bisacrylic type as disclosed in EP-A-0 216 712 and EP-B-0 847
432, US-B-6,589, 445, which are herein included by reference.
The preferred amount of the nematic compound présent in the cholesteric liquid crystal precursor mixture is from about 10 wt% to about 60 wt%, more preferably from about 10 wt% to about 45 wt%.
The preferred chiral inducers are selected from the dérivatives of isosorbide and isomannide, disclosed in EP-B-0 739 403, GB-A-2 330 139, and US-B-6,589,445, which are herein included by reference. The amount of the chiral inducer présent in the cholesteric liquid crystal precursor mixture ranges from. about 0.1 wt% to about 25 wt%, preferably from about 0.5 wt% to about 15 wt%.
The liquid crystal precursor material for producing a marking according to the présent invention may further comprise dyes, 10 pigments, coloring agents, diluents, conducting salts, surface-active compounds, surface adhesion promoters, wetting agents, defoamers, and dispersing agents.
The marking of the présent invention is preferably applied in the form of indicia representing a unique 1-dimensional, a stacked 1-dimensional, or a 2-dimensional barcode or matrix code. The symbology is preferably chosen among those used in the retail industry for the marking of commercial goods. These symbologies are internationally recognized standards, and the 20 corresponding reading and decoding algorithme are known and implemented in comme.rcially available devices.
Suitable 1-dimensiona.l and stacked l-dimensional barcode symbologies are known to the skilled person and available under symbology names such as Plessey, U.P.C., Codabar, Code
- Non-interleaved 2 of 5, Code 25 - Interleaved 2 of 5, Code 39, Code 93, Code 128, Code 128A, Code 128B, Code 128C, Code 11, CPC Binary, DUN 14, EAN 2, EAN 5, EAN 8, EAN 13, GS1128 (formerly known as UCC/EAN-128) , EAN 128, UCC 128, GSI
DataBar formerly Reduced Space Symbology (RSS), ITF-14, Pharmacode, PLANET, POSTNET, OneCode, MSI, PostBar, RM4SCC / KIX, or Telepen.
Suitable 2-dimensional barcode symbologies are known to the skilled person and available under symbology names such as 3-DT, ArrayTag, Aztec Code, Small.Aztec Code, bCODE, Bullseye, Codablock, Code 1, Code, 16K, 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. This latter has a built-in error correction code and is defined in international standard ISO/CEI 16022:2006.
Suitable font types for optical character récognition (OCR) are known to the skilled person.
F.ig.l schematically shows a producL packaging having a * cholesteric liquid crystal marking of the présent invention. The marking is présent in the form of a ECC200 data matrix code on the surface of said packaging. Data Matrix ECC200 is a public domain symbology. The marking can be applied to any desired position on the packaging. Thus it can be présent wholly on a first background color (a) , or partially, « overlapping with a first background color and a second design color motive présent on the packaging (b) , or wholly be présent on a white or colorless région of the packaging (c) .
The reading device for reading the marking of the présent invention can be constructed on the basis of commercially available barcode readers, in particular on the basis of handheld CCD/CMOS-caméra reading equipment and reading stations used in the retail industry. In case of an appropriate matching of the marking with the available (narrow-band) illumination, said reading eqüipment may be directly enabled to read the liquid crystal codes.
In other cases, the reading device can be further adapted (enabled) so as to read the response of the spécifie security éléments implemented in the marking. Correspondingly adapted flat-bed scanners can also be used. CCD-camera based barcode readers are known to the skilled person and are produced by several industrial companies, such as AccuSort, Cognex, DVT, Microscan, Omron, Sick, RVSI, Keyence, etc.
Said adaptation of the reading device may comprise the implémentation of one or several optical filters chosen from the group of linear polarizing filters, right-circular polarizing filters, Left-circular polarizing filters, electrooptic polarization filters, wave-plates, and spectrally sélective color filters of any type, and combinations thereof. In a particular embodiment at Ieast two different optical filters are used. Said adaptation may further comprise the implémentation of one or several particular light sources chosen from the group of spectrally sélective (i.e. colored) light sources, linear polarized light sources, left- and right-circular polarized light sources, and combinations thereof.
The light sources, however, can be chosen from ambient light, incandescent light, laser diodes, light emitting diodes, and ail type of light sources having color filters. Said light sources may hâve an émission spectrum in the spectral domain of the visible light (400-700nm wavelength) , the near optical infrared (700-1100nm wavelength), the far optical infrared (1100-2500nm wavelength), or the UV (200-400nm wavelength) région of the electromagnetic spectrum.
3l
Said reading device is thus not only enabled to read the marking, but also to authenticate it as being made of the correct security material, i.e. comprising the required 5 security éléments. Said reading device delivers a digital information représentative of the code which has been read, and pointing towards an entry in a data base corresponding to the item carrying the said marking and code.
Said digital information may be compared with information stored in the reading device or may be exchanged between the reading device and an external data base; the exchange can take place in encrypted form, using e.g. a public/private encoding of the RSA type. Said exchange of information can 15 take place by ail kind of transmission means, e.g. wire-bound transmission, wireless radio link, infrared-link, etc... .
In the particular case where no chiral inducer is comprised i.n the precursor material, a nematic liquid crystal polymer is 20 obtained, Such polymer is usually characterized by biréfringence, i.e. the molécules in a printed layer are oriented in a prédominant direction, and the component of the refractive index along the molecular axes is different from the component of the refractive index orthogonal to the 25 molecular axes.
Such nematic liquid crystal polymer can serve as a security element, by using its biréfringent properties, in which case it acts as a wave plate, able to transform linear polarization 30 into circular polarization, or vice versa, at appropriate layer thickness. In case of a reflective substrate, the presence or absence of the applied liquid crystal polymer can then be revealed with the help of a linear polarizing filter placed on top of the marking ïn appropriate orientation. In case of a transmissive substrate, either a reflector or a second polarizing filter needs to be applied at the back side of the substrate in order to render the marking visible.
In a second embodiment, the marking of the présent invention consists of pigment flakes of a liquid crystal polymer; said pigment flakes being comprised in 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 Al, which is included by reference herein. A marking according to the présent invention comprising such a pigment exhibits at least two reflection bands in the 200nm to 2500nm wavelength range.
Cholesteric liquid crystal polymer (CLCP) pigments useful to carry out the présent invention are disclosed in EP 1 213 338 Bl; EP 0 '685 749 Bl; DE 199 22 158 Al;' EP 0 601 483 Al; DE 44 18 490 Al; EP 0 887 398 Bl, and W02006/063926. Reference is also made to US 5,211,877, to US 5,362,315 and to US 6,423,246. Such particles hâve a thickness of the order of 1 to 10 micrometers and a flake size of the order of 10 to 100 micrometers, and are obtained by comminuting a corresponding liquid crystal polymer film. The preferred flakes for use in the présent invention hâve a thickness in the range of 1 to 10 micrometers, and an average flake d.iameter in the range of 20 to 50 micrometers.
Said coating composition comprises at least one binder as a mandatory component; optionally, further pigments, dyes, extenders, additives, photoinitiators, etc. may be présent, as required by the application process and the substrate to be marked.
resins, resins, modified
Preferred binders are chosen from acrylic resins, styrene-maleic polyacetal polyester resins, polyester resins and UV the group of vinylic anhydride copolymer resins, fatty acid oligomers, such as mixtures thereof.
acrylates, vinyl curing monomers ethers, epoxides and and
Said coating composition may preferably comprise further security materials, which are présent in low to moderate concentration, in order to increase its résistance towards counterfeiting. These security materials are selected from the group consisting of the inorganic luminescent compounds, the organic luminescent compounds, the IR-absorbers, the magnetic materials, the forensic markers, and combinations thereof.
Typical concentration ranges are 0.01% to 5% for luminescent compounds, 0.1% to 10% for IR-absorbers or magnetic materials, and 0.001% to 1% for forensic marker materials.
To accommodate particular conditions, the coating composition for producing a marking according to the présent invention may further comprise dyes, pigments, coloring agents, diluents, conducting salts, surface-active compounds, surface adhesion promoters, wetting agents, defoaroers, and dispersing agents, as known in the art.
The authentication and identification of the liquid crystal marking according to the présent invention requires a light source and must be done in one of the following ways:
i) by illuminating the marking with circular or linear polarized light and detecting the marking's reflection;
ii) by illuminating the marking with unpolarized (e.g. ambient) Light and detecting the marking's reflection through a circular or linear pol.arizing filter, iii) by a combination of circular or linear polarized illumination and détection through a circular or linear polarizing filter.
The illumination of a marked item or article is thus performed by a light source chosen from unpolarized light sources, linear polarized light sources, left circular polarized light sources, and right circular polarized light sources.
In ail cases, détection may be performed by eye or with the help of electro-optic détection equipment, such as a photocell, or a CCD or CMOS caméra. The light sources and the détection may be made or chosen spectrally sélective through the use of particular light emitters and/or color filters. The 15 détection is preferably carried out in the visible région (400-700nm wavelength) of the electromagnetic spectrum.
In a particular embodiment the illumination of the marking for aut'henticating an item or article, is performed using at least 20 two different light sources selected from non-polarized (randomly polarized) light sources, linear polarized light sources, left circular polarized light sources, and right circular polarized light sources.
Fig.2 shows images taken from ECC200 Data matrix codes printed with liquid crystal material on coated cardboard. These images clearly illustrate the advantage of using the polarizing properties of the liquid crystal material marking for the reading of the printed code on a clear or structured 30 background. Most advantageous is a combination of polarized light for illumination and the use of a polarizing filter in front of the caméra. Ail images were taken with the same light source and with the same caméra settings, ail in black and white mode, and with or without polarizing filters before the light source and/or the caméra. The images were digitally treated for maximum contrast and optimum brightness.
In a preferred option, the liquid crystal marking of the présent invention ïs rendered visible under unpolarized (preferably ambient) Light by a passive detecting means such as a linear or a circuler polarizing filter. The marking can, however, also be identified and authenticated outside the visible spectrum (400-700nm wavelength), e.g. in the infrared région (700 to 2500nm wavelength) , preferably in the near optical infrared (700“1100nm wavelength), in the far optical infrared (1100-2500nm wavelength) or in the UV (200-400nm wavelength) région of the electromagnetic spectrum, given that t.he marking has a reflection band in these régions.
The cholesteric liquid crystal polymer is, by its nature, a spectrally sélective reflector whose reflection band can be tuned across part of the electromagnetic spectrum by an appropriate choice of its helical pitch. Said pitch noteworthy dépends on the ratio of nematic precursor material to chiral inducer compound in the liquid crystal precursor, and on the température of polymérisation. After polymerization, the helical pitch, and hence the reflection color of the material, remains fixed.
As known to the skilled person, low amounts of chiral inducer resuit in a low helical twisting and hence in a large helical pitch. Therefore, low amounts of the chiral inducer generate a reflection band of the resulting polymer at the long wavelength end of the spectrum, typically in the infrared or red région, whereas higher amounts of inducer generate a reflection band of the resulting polymer at the short wavelength end of the spectrum, typically in the blue or UV région.
Attention must also be paid tù the handedness of the chiral inducer, i.e. whether a determined inducer results in a left or in a r.ight helicaL pitch, resulting in respective opposite circuler polarization of the reflected light. Isomannide dérivatives are known to induce the reflection of left circular polarized light, whereas isosorbide dérivatives are known to induce the reflection of right circular polarized light.
«
Hereafter is given a typical example of a cholesteric liquid crystal polymer precursor composition, which can be applied by the continuous ink-jet printing process:
MEK 55.7 wt% benzoic acid 4-|4-[ {l-oxo-2-propenyl)oxy] butoxycarboxy]-, ·
2-methyl-l,4-phenylene ester 40.1 wt% (3R, 3aR, 6S,6aR)-hexahydrofuro[3,2-b]furan-3,6-diyl bis(4-
(acryloyloxybutoxy)benzoate) 1.70 wt%
Irgacure 907 1.30 wt%
LÏCJO4 1.20 wt%
The following example is a typical cholesteric liquid crystal polymer pigment composition, which can be applied by the valve-jet (drop-on-demand) ink-jet printing process:
Pioloform® BL18 5.0 wt%
MEK 64.6 wt%
Diethylene glycol 10.0 wt%
Ethanol - 8.0 wt%
LC polymer pigment 10.0 wt%
Byk®-430 1.5 wt%
Byk®-410
0.9 wt%
Pioloform® BL18 is a polyvinyl butyral resin with the CAS No. 63148-65-2 supplied by Wacker. Byk®-430 is a solution of modified urea supplied by Byk. Byk®-410 is a solution of high molecular urea modified polar polyamide supplied by Byk.
The following is an alternative example of a cholesteric liquid crystal polymer precursor composition, which can be applied by the valve-jet printing process:
MEK 83.0 wt% benzoic acid 4-[4-[(l-oxo-2-propenyl)oxy] butoxy]-, 2methyl-1,4-phenylene ester 14.7 wt% (3R, 3aR, 6S, 6aR) -hexahydrofuro [3, 2—b ] furan-3,6-diyl bis (4(acryloyloxybutoxy)benzoate) 1.50 wt%
Irgacure 907 0.8 wt%
Based on the indications and exemplary embodiments given hereinbefore, the skilled person is enabled to dérivé further embodiments of the présent invention.

Claims (5)

  1. Claims
    1. Marking for an item or article, said marking comprising polymcric liquid
    5 crystal material having determined optical charaeteriatics which allow for ite authentication and reading by a machine, as well as its authcntication by the human eye, the marking b oing characterized-in that it is produced on a substratc by a i
    variable information printing process selected from the group continuous ink-jet printing, drop-on-demand ink-jet printing, and laser printing, and has tho form of 10 indicia representing a unique code, allowing for its identification.
  2. 2. Markiiig according to claim 1;characterized in that at least part of the marking is invisible to the unaidedhuman eye.
    15 3. Marking according to one of the daims 1 to 2, wherein said polymeric liquid crystal material is a cholesteric liquid crystal material, exhibiting color and an angle- dépendent change of color.
    4. Marking according to claim. 3, wherein the cholesteric liquid crystal mate-
    20 rial has a reflection band in tho UV spectrnm corrcBponding to the 200 to 400nm wavelength range.
    5. Marking according to claim 3, wherein the cholesteric liquid crystal matériel has a reflection band in the visible spectrum corresponding to the 400 to
    25 700nm wavelength range. <
    6. Markmg according to claim 3, wherein the cholesteric j t!
    T
    Qi ii «, !·· i
    fi b |r' i' ii ?;
    r i J S ;
    liquid crystal material has a reflection band in the infrarcd spectrum corresponding to the 700 to 2500nm wavelength range, preferably in the infrarcd spectrum correspondingtothe700to IIOOnmwavelengthrange.
    5 7. Marking according to one of the daims 4 to 6, wherein. tho cholesteric liquid crystal material has a second reflection.band in the 200 to 2500nm wavelength range.
    8. Marking according to one of the daims 1 to 2, wherein said polymètre
    10 liquid crystal material is a neamatic liquid crystal material, exhibiting optical biréfringence.
    9. Marking according to one of the daims 1 to 8 , wherein said polymcric liquid crystal material comprises further security materials, selected from the
    15 group consisting of the inorganic luminescent compounds, the organio luminescent compounds, the IR-absorbers/the magnetic materials, and the forensic markers, and the combinations thereof.
    10. Marking according to one of thedaims 1 to 9, wherein said substrate is
    20 selected fiom tho group of reflecting substrates, colored substrates, and transpar-<j i eut substrates. »
    11. Marking according to one of the daims 1 to 9, wherein said substrate is a, pattemed substrate, comprising at least two different surface areas, each selectedJ
    25 from the group of white surface areas, black surface areas, colored surface areas,] reflecting surface areas, transparent surface areas and combinations thereof.
    «
    12. Marking according to one of the daims 1 to 9, wherein said substrate car- nes îndicia.
    13. Marking according to one of the daims 1 to 9, wherein said substrate cardes at least one security clément, selected from the group consisting of the inorganic luminescent compounds, the organic luminescent compounds, the IRabsorbers, the magnetic materials, the forensic markers and combinations thereof.
    5 '
    14. Marking according to daim 13, wherein said security élément is présent in the form of indicia.
    15. Marking according to one of the daims 1 to 14, wherein said substrate is 10 selected from the group consisting of the woven substrates, the non-woven substrates, the coated substrates, the papers, the cardboards, the wooden substrates, the glass substrates, the ccramic substrates, the métal substrates, the plastic substrates, the textiles, and the leathers,
    15 16. Marking according to one of the daims 1 to 15, wherein said indicia representing a unique code are chosen from the group of: 1 -dimcnsional barcodes, stacked 1-dimcnsional barcodes, and 2-dimcnsional barcodes,
    17. Marking according to daim 16, wherein said 1-dimcnsional barcode is
    20 selected from the group of Plessey, U. P. C.,
    Codabar, Code 25 - Non-interleaved 2 of 5, Code 25 - Interleaved 2 of 5 , Code
    39, Code 93, Code 128» Code 128A, Code 128B, Code 128C, Code 11, CPC Binary, DUN 14, EAN 2, EAN 5, EAN 8, EAN 13, GS1-128 (formerly known as UCC/EAN-128), EAN 128, UCC 128, GSI DataBar formerly Reduced Space
    25 Symbology (RSS), ΠΈ-14, Pharmacode, PLANET, POSTNET, OneCode, MSI, PostBar, RM4SCC / KIX, or Telepen.
    18. Marking according to daim.16, wherein said 2-dimensional barcode is selected from the group of 3 -DI, ArrayTag,
    30 Aztec Code, Small Aztec Code, bCODE, Bullseye, Codablock, Code I, Code, 16K, Code 49, Color code, CP Code, DataGlyph9, Datamatrix, Datastrip Code, •U·'
    4 16616 * - ... — 41 —=- —— _ * V
    ? i ;· t :
    &
    t' >>
    ?!
    f h
    II ’i» J; k .r » . i, 9 &
    Dot Code A, EZcode, High Capacity Color Baroode, HueCode, INTACTA. CODE, InterCode, MaxiCoda, mCodc, MiniCode, PDF417, Micro PDF417, PDMark, PapcrDisk, Optar, QR Code, Semacode, SmartCode, Snowflake Code, ShotCode, SuperCodc, Trillcode, UltraCode, VeriCode, VSCode, WatcrCode, and 5 ECC200.
    19. Marking according to one of the daims 1 to 18, wherein the polymeric liquid crystal material is présent in the form of pigment flakes comprised in a suitable binder.
    20. Marking according to claim 19, wherein the binder is chosen from the group consisting of the vinylic resins, the acrylic resins, the styrene-malcic anhydride copolymer resins, the polyacetal resins, the polyester resins, the fatty acid modified polyester resins and the mixtures thereof.
    21. Marking according to claim 19, wherein the binder is choscn from the group consisting of the UV-cure-ablc monomers and oligomers of acrylatcs, vinyl ethers, epoxides and combinations thereof. · 20 22. Item or article cairying at least one marking according to one of the daims lto21.
    23, Item or article according to daim 22, wherein said item or article is choscn from the group of value documents, banknotes, passports, identity documents,
    25 driving licences, official permissions, access documents, stamps, tax stamps and banderoles, transportation tickets, event tickets, labels, foils, packaging, sparc parts, and consumer goods .
    24, Use of a marking according to onc of the daims 1 to 21 for traddng or t4 i
    P
    1 d fl ij «I fi
    30 tracing an item or artidè. 16616
    25. Use according to claim 24, wherein said item or article is chosen from the group of value documents, banknotes, passports, identity documents, driving licenses, official permissions, access documents, staœps, tax stamps and banderoles, transportation tickets, event tickets, labels, foils, packaging, sparo parts, and
    5 consumer goods.
    26. Method for producing a marking according to one of claims 1 to 21, said method comprising the steps of
    a) providing a substrat©;
    10 b) applying a liquid crystal precursor composition to said substrate, in the form of indicia;
    c) hardening the applied composition in the ordered liquid crystal state.
    27. Method according to claim 26, wherein the precursor composition com-
    15 prises UV-cure-ablc reactive monomers or oligomers, and the hardening of the applied composition takes place by UV-curing.
    t
    1' .
    28. Method for marking an item or article, said method comprising the steps of
    a) providing an item or article to be marked;
    20 b) applying at least one marking according to one of the claims 1 to 21 onto the said item or article,
    29. Method according to one of claims 26 to 28, wherein tire unique code represented by the indicia is an encrypted information, the method comprising the
    25 step of cncrypting said information.
    30. Method for authenticating an item or article, said method comprising the steps of
    a) providing an item or article cartying a marking according to one of the claims 1 30 to21;
    ί’ ι 4 i
    f * ? b 1’
    L
    1 i
    b) illuminuting the marking on said article or item with at least one quality of light from at least one light source;
    c) detecting the said marking'g determined optical cbaractcristics through the sensing of light reflected by the marking;
    5 d) determining the itcm's or artide's authentfcâty from the detected optical characteristics of the marking .
    31. Method according to claim 30, whereinthe marking comprises a cholesteric liquid crystal material, exhibiting spectrdly sdective, viewing angle-
    10 dépendent light reflection, the reflected light having a particular sense of circuler polarisation.
    32. Method according to one of daims 30 to 31, wherein said light source is a spcctrally sélective light source.
    33. Method according to claim 32, whereinsaid light source is chosen from the group of ambient light, incandescent light, laser diodes, light emitting diodes, and the light sources having color fîlters.
    20 34. Method accordingto one of daims 30 to 33, wherein the light source is chosen to émit in a spectral domain of the group consisting of the visible (400700nm wavelength) , the ncar optical infrared (700-1 lOOnrn wavelength) , the far optical infrared (1100-2500nm wavelength) and the UV (200-400nm wavelength) région of the clcctromagnetio speotrum.
    35. Method according to one of daims 30 to 34, wherein said illummating is perfoimcd by a light source chosen from the group consisting of the unpolarized, linear polarized, left cîrcular polarized, and right oircular polarized light sources.
  3. 3û 36. Method according to one of daims 30 to 35, wherein at least two different said light sources are used in conjunction.
    Η ii ,ί
    37. Method according to one of claim 3 0 to 36, wherein said dctccting is perfotmed using at least one optical filter chosen from the group consisting of the linear polarizing, left circular polarizing, right circuler polarizing filtera and the
  4. 5 clcctro-optic polarization switches.
    38. Method according to claim 37, wherein said optical filter is combined with a color filter.
  5. 10 39. Method according to one of daims 37 to 38, wherein at least two different said optical filtera are used in, conjunction.
    40. Method according to one of daims 30 to 39, wherein said detecting is performed by eye.
    41. Method according to one of daims 30 to 39, wherein said detecting is performed by an electro-optic détection equipment,
    42. Method according to daim 41, wherein said electro-optic detecting equip20 ment is chosen from the group consisting of the photocells, linear CCD image sensor arrays, 2- dimensional CCD image sensor arrays, linear CMOS image sensor arrays, 2 -dimensional CMOS image sensor arrays.
    43. Method for identifying an item or article, said method comprising the steps 25 of
    a) providing an item or artide carrymg a marking according to one of the daims 1 to 21;
    b) illuminating the marking on said artide ot item with at least one quality of light from at least one light source;
    30 c) reading the indicîa represented by the marking, deriving corresponding information;
    l
    Μ ‘ * :
    ; » ;4
    d) correlating the information retrieved from the indicia of the marking with information stored in a data base ;
    e) obtaining confirmation or déniai concerning the item's or article's identity.
    5 44. Method according to claim 44, comprising the further step of authenticating said item of article using the method according to one of daims 30 to 42,
    45. Method according to one of daims 43 to 44, wherein the indicia are read with the help of an. dectro-optic image sensor aixay.
    46. Method according to daims 45 wherein the dectro-optic image sensor array is chosen from the group co'nsisting of the lincar CCD image sensor arrays, 2 -dimensional CCD image sensor arrays, linear CMOS image sensor arrays, and 2 -dimensional CMOS image sensor arrays.
    47. Method according to one of daims 43 to 46, wherein information about the item or article is stored in ttwdatabase.
    1 :
    â:
    F!* U
    Ü i ;
    i
    48. Method according to one of daims 43 to 47, wherein the information ex-
    20 change with the database takes place in cncrypted form.
    a
    49. Method according to one of daims 43 to 48, wherein the unique code represented by the indicia of the markmg is cncrypted information, the method comprising the step of decrypting said information.
    50. Method for the secure trackîng or tracing of an item or article, using a · marking according to one of the daims 1 to 21, comprising the first commutable step s of
    a) applying a said marking to the item or article according to onc of the daims 26
    30 to29;
    b) storing information related to the marked item or artide in a data base;
    S' and the second commutable steps of
    c) authenticating the item or article according to one of the daims 30 to 42;
    d) identifyliig the item or artiole, according to one of the daims 43 to 49, using the information storcd in the data base;
    5 and the optional step of
    e) updating the data base with new information dements related to the item or article.
    51. Method according to claim 50, wherein said item or artîde is choscn from 10 thé group of value documents, banknotes, passports, identity documents, driving liccnses, official permissions, access documents, stamps, tax stamps and banderoles, transportation tickets, event tickets, labels, foils, packaging, pharmaceutical products, spare parts, and consumer goods.
OA1201000332 2008-04-02 2009-04-02 Identification and authentication using liquid crystal material markings. OA16616A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
IBPCT/IB2008/000785 2008-04-02

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Publication Number Publication Date
OA16616A true OA16616A (en) 2015-12-01

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