OA20916A - Machine-readable polymer security threads. - Google Patents

Abstract

A method and associated system for authentication, including irradiating an item including a polymer security thread including a polymer material and a doping material within the polymer material and configured to produce a radiation spectrum in response to the irradiating, the doping material capable of absorbing, scattering, or emitting radiation, and detecting the produced radiation spectrum to confirm the presence of the polymer security thread.

Description

PCT INTERNATIONAL APPLICATION

FOR

MACH1NE-READABEE POLYMER SECURITY THREADS

CROSS-REFERENCE TO RELATED APPLICATIONS

The application is a PCT international application, which daims priority to U.S. patent application Ser. No. 16/848,930, filed April 15, 2020.

TECH1CAL FIELD

The présent invention relates generally to products, apparatuses, and methods in which items include polymer security threads containing doping materials, the doping materials being détectable through radiation spectra generated in response to incident radiation.

BACKGROUND OF THE INVENTION

Counterfeiting is a growing concern and, as a resuit, secure instruments such as banknotes typically hâve three levels of authendcation. Level I authenticatîon is for public uses and is typically in the form of an optical effect, such as optically variable ink or security threads with optical characteristics that are relatively unique and difficult to duplîcate. These Level I authenticatîon features include holographie threads and lentîcular lens array security threads. Paper banknotes hâve included Level I authenticatîon features in the form of watermarks.

Similar to Level J authenticatîon features, Level 11 authenticatîon features are typically known to the public and commercial banks, and include features such as magnetics and fluorescent and phosphorescent înks, which can be read by simple sensors commonly used in ATMs and bill acceptors.

Level III securîty features are machine readable features and are more sophîsticated than Level II authentication features. Level TII securîty features are typically not known to the public 5 and commercial banks and are used to protect against threats from state-sponsored counterfeiters and other well-funded organizations. The covert Level III authentication features are typically either in the form of inks or other features embedded in the substrate of the banknotes.

Over the last two décades, polymer banknotes hâve gradually been gaining market share in the banknote industry, with over thirty countries using polymer substrates including materials 10 such as bîaxially oriented polypropylene (BOPP). The use of polymer substrates has been primarily restricted to lower dénominations, as most of the Level III securîty features that hâve been employed within paper banknote substrates are not available or suitable for use with polymer banknotes.

Additionally, securîty threads are used as security features in banknotes, high value 15 documents, and government documents in many countries as well as in product labels and some fabrics. Security threads may be embedded within the banknote or windowed in an alternating manner between being on and within the banknote. Security threads typically hâve widths ranging from one millîmeter to one centimeter.

Security threads are used in ail of the top five dénominations of United States (US) currency 20 and may émit spécifie phosphorescence or fluorescence under ultraviolet (UV) excitation. Security threads can also carry de-metalized printing, which may be read under ambient light when the banknote or substrate is examined in transmission.

Securîty threads can hâve different constructions ranging from a simple fiat strip of a polymer, such as polyethylene terephthalate (PET) or BOPP, having a thickness ranging from 5-50 microns with de-metallization and a phosphor layer or as a sandwich structure including two more layers containing various coatings. There are other variants for securîty threads that include optical 5 refractive and diffractive structures to create an optical variability when viewed from different angles. Such a securîty thread is used in the US $100 banknote.

The présent invention concems securîty features in the form of a machine readable technology for use with polymer securîty threads in banknotes, including banknotes containing polymer-based substrates.

SUMMARY OF THE INVENTION

In general, in one aspect, the invention features a method for authentication, including irradiating an item including a polymer securîty thread including a polymer material and a doping material within the polymer material and configured to produce a radiation spectrum in response 15 to the irradiating, the doping material capable of absorbîng, scattering, or emitting radiation, and detecting the produced radiation spectrum to confirm the presence of the polymer securîty thread.

Implémentations of the invention may include one or more of the following features. The produced radiation spectrum may be a spectral signature distinct from a spectrum of the 20 irradiating. The method may further include detecting the spectral signature in the produced radiation spectrum, and determining a code associated with the spectral signature. The method may further include comparing the determined code to a reference code, and providing an indication of authenticity if the determined code matches the reference code. The spectral signature may be an absorption or scattering pattern in the produced radiation spectrum. The produced radiation spectrum may include visible light or non-visible electromagnetic radiation. The doping material may be capable of absorbing, scattering, or emitting radiation at a plurality of spécifie wavelengths to produce the spectral signature. The absorbed, scattered, or emitted 5 radiation at the plurality of spécifie wavelengths may hâve difièrent intensifies at each of the plurality of spécifie wavelengths.

The polymer security thread may hâve a thickness of 5 to 70 microns. The polymer security thread may be disposed in or on a substrate. The substrate may be a paper substrate or a composite polymer-paper substrate. The polymer security thread may be a single layer within 10 the substrate, may be disposed between two layers, or may be wîndowed in the substrate in an alternating manner. The polymer security thread may be disposed between two layers, and each of the two layers may include a phosphor. The item may be currency.

In general, in another aspect, the invention features a system for authentication, including a radiation source for irradiating an item including a polymer security thread including a polymer 15 material and a doping material within the polymer material and configured to produce a radiation spectrum in response to the irradiating, the doping material capable of absorbing, scattering, or emitting radiation, and a sensor configured to detect the produced radiation spectrum to confirm the presence of the polymer security thread.

Implémentations of the invention may include one or more of the following features. The 20 polymer security thread may hâve a thickness of 5 to 70 microns The polymer security thread may be disposed in or on a substrate. The substrate may be a paper substrate or a composite polymer-paper substrate. The polymer security thread may be a single layer within the substrate, may be disposed between two layers, or may be windowed in the substrate in an alternating manner. The polymer security thread may be disposed between two layers, and each of the two layers may include a phosphor. The sensor may include an imaging device of a smartphone or a tablet.

BRI EF DESCRIPTION OF THE FIGURES

Figure l shows an exemplary authentication system in accordance with embodiments of the invention;

Figure 2 shows an exemplary System that may be employed to authenticate an item using the method of the présent invention; and

Figure 3 shows an exemplary screen shot of a software application that may be utilized on a smartphone for authenticating an item in accordance with the présent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The présent invention provides for products, apparatuses, and methods relatîng to items embedded with polymer security threads having doping materials therein or thereon, and authentication Systems and methods using the doped polymer security threads. The doped polymer security threads may be used, e.g., for authenticating secure items, instruments or documents, such as banknotes or currency. In one embodiment of the présent invention, the doped polymer security thread is embedded in a sub strate and configured as a machine-readable security feature that absorbs or emits, i.e., produces, spécifie radiation in response to irradiating the substrate from a radiation source, which may be part of an authentication and détection device.

A polymer security thread employed in the présent invention may be composed of a polytneric material, including but not limited to polyester or polypropylene, e.g., BOPP. The polymer security thread, as used m, e.g., banknotes or cunency, may be approximately 5 to 70 microns in thickness.

Doping materials may be nanometer and micrometer materials added to the polymeric material. The doping materials may be added to the polymeric material during extrusion. The doping materials may be added to or loaded in the polymeric material at 0.01-10% loadings by weight The doping materials may be inorganics, organics, semiconductor and nanostructures exhibiting ex ci ton, phonon polariton and plasmonic modes, and particularly those that can survive the extrusion températures of the polymeric material. The doping materials may optionally be selected to be well matched to the index of refraction of the polymeric material and to maintain the clarity and transparency of the polymeric material. Additionally, the dopcd polymer security thread may be embedded in a scattering substrate, e.g., paper, such that the clarity or haze of the doped polymer security thread is not critical, unlike embodiments in which the security thread is disposed in a windowed région of the substrate, e.g., banknotes containing polymer-based substrates.

Each doping material may exhibit a unique absorptive or scattering property or signature in the spectrum of incident radiation transmitted through the polymeric material in the région from the far infrared to the long ultraviolet. In particular, the doping materials selectively absorb or scatter incident radiation at spécifie wavelengths. By combining spécifie absorption or scattering features of varions doping materials, codes for authenti cation of the security thread and associated items, e.g., banknotes, may be created, including in the form of patterned spectra with notches or other nonuniform features, i.e., absorption or scattering patterns.

In addition, the doping materials may include materials such as phosphors and narrow-band rare-earth and transition métal compounds that émit radiation of a particular wavelength, upon

excitation by radiation transmitted directly or laterally through the thread, such as in waveguide modes in the substrate initiated by scattering. The émission features of such doping materials may be combined with the absorption or scattering features of the doping materials to create patterned spectra for the authentication codes. The doping materials may be selected to be index matched with the polymeric material. Alternatively, the doping materials may be selected not lobe index matched with the polymeric material to allow for scattering of radiation transmitted through the polymeric material, which may optionally include being at sufficiently low concentrations to maintain the clarity and transparency of the polymeric material, such as with a transparent or colorless polymers, e g., BOPP.

The dopcd polymer security thread may be embedded in any industry-acceptable substrate, including paper substrates and composite polymer-paper substrates. The substrate may be covered with an opacity layer to allow for both contrast printing and discharge of static charges. Alternatively, the substrate may include a clear area or window free from opacity, as is often the case in higher dénomination banknotes containing polymer-based substrates. The opacity layer 15 ofthe banknote, either alone or in combination with the area free from opacity, may fonction as the analog of paper banknote watermark for banknotes containing polymer-based substrates. In one embodiment of the présent invention, the doped polymer security thread includes metallized aluminum thereon. The doped polymer security thread may be disposed in the substrate in any industry-acceptable configuration, including but not limited to a single layer, a sandwiched 20 layering (including phosphor-based layers disposed on one or both sides), a windowed arrangement, and the like.

In one embodiment of the présent invention, the security thread with doping material embedded therein may be configured to contribute to the functioning of the substrate as a waveguide for radiation transmitted by or through the thread, i.e., through total internai refiection between the upper and lower surfaces of the polymer layer. In particular, the combination of the substrate and the security thread is configured as a planar dielectric waveguide capable of transmitting electromagnetic radiation laterally through the polymer layer in a waveguide mode between the upper and lower surfaces. Incident radiation may enter the thread on or in the substrate through extemal coupling at the upper or lower surface of the polymer layer followed by internai scattering. Such scattering mediated waveguide coupling is an alternative mode for radiation to enter the planar waveguide ofthe thread compared to directing the radiation through an edge ofthe thread. The same mode of scattering can result in external coupling and may be used to découplé radiation transmitted through the substrate containing the security thread for détection. Upon détection, i.e., through decoupling after waveguide transmission, the spectrum of radiation may be detected or analyzed, încluding for patterns such as notches resulting from narrow-band absorption by the doping material.

The process of authenticaîing an item such as a banknote încluding a security thread as described herein may be perfbrmed using apparatus capable of generating incident radiation for transmission by or through the thread and detecting radiation transmitted by or through the thread. Such authenti cation may be performed on high-speed transport mechanisms, such as those used to process currency at a rate of 40 banknotes per second.

Exemplary embodiments of the présent invention are generally directed to devices, apparatus, Systems, and methods for authentication using doped polymer security threads. Specifically, exemplary embodiments of the présent invention use detecting/sensing mechanisms that may be used to authenti cate items încluding a doped polymer security thread. Although the exemplary embodiments of the présent invention are primarily described with respect to authentication and/or preventing counterfeiting, it is not limited thereto, and it should be noted that the exemplary doped polymer security thread may be used to encode other types of information for other applications. Further, the exemplary embodiments of the présent invention may be used in conjunction with other authentication measures, e.g., holograms, watermarks, 5 and magnetic encoding.

Figure 1 shows an exemplary System 100 in accordance with embodiments of the présent invention. As shown in Figure 1, System 100 may include a radiation/excitation source 102,asensor 104, and a substrate 106 having a doped security thread 107. Radiation/excitation source 102 may be any source supplying radiation 108, such as, e.g., visible light, ultraviolet 10 radiation, radio waves, or microwaves, which is to be absorbed and/or scattered by the doped security thread 107. The doped security thread 107 may produce radiation 110 in the same wavelength range or a different wavelength range.

Sensor 104 may include any detecting, sensing, imaging, or scanning device that is able to receive, image or measure the spectrum of the radiation produced by the doped security I5 thread substrate 107, such as a photometer or a digital caméra.

According to certain exemplary embodiments of the présent invention, radiation/excitation source 102 may include the flash of a digital caméra, and sensor 104 may include the optical components and sensors of the digital caméra. In one exemplary embodiment, the radiation/excitation source 102 may include the light source of a smartphone 20 or tablet caméra, e.g., Apple iPhone, Apple iPad, Samsung Galaxy or other Android devices, and sensor 104 may include the caméra of the smartphone or tablet.

Sub strate 106 having doped security thread 107 may be included in labels and may be attached or affixed to any product or item, e.g., tax stamps, apparel, currency, or footwear, for which authentication may be désirable.

Figure 2 shows an exemplary System 200 that may be employed to authenticate an item including a substrate with doped security thread described herein. For example, System 200 includes a computing device 202, which may include radiation/excitation source 102 and sensor ] 04. Computing device 202 may be any computing device that incorporâtes a radiation/excitation source 102 and sensor 104, such as a smartphone, a tablet, or a personal data assistant (PDA). Altemativeiy, radiation/excitation source 102 and sensor I04 may be stand- alone devices that operate independent of a computing device. As described herein, the radiation/excitation source 102 may irradiate a doped security thread, and sensor 104 may measure the radiation produced by the doped security thread, including a spectral signature. In embodiments in which the produced radiation is a spectral signature, the spectral signature may be distinct from an irradiation spectrum associated with a radiation/excitation source, e.g., radiation/excitation source 102. The computing device 202 may détermine a code corresponding to the measured spectral signature of the radiation produced by the doped security thread. The processing of the measured spectral signature to détermine the code may be performed by a remote computing device. Subsequently, the code or the measured spectral signature may be compared to a database of reference codes or spectral signatures. The database of reference codes may be stored locally on the scanning, imaging, or sensing device or remotely on a separate computing device.

As shown in Figure 2, to complété the authentication, the computing device 202 may compare the code or the measured spectral intensifies to the reference codes or spectral signature stored in a database 204. Although Figure 2 illustrâtes this coin pari son being performed via a network 206 to a remote database 204, other embodiments contem plate database 204 being local to computing device 202.

Further, in some embodiments, the item being authenticated may include an identifying label, such as, e.g., a barcode, a QR code, or a magnetic code, to enable corrélation of the code or the measured spectratothe item being authenticated. In aparticular embodiment where computing device 202 is a smartphone or tablet, the transmission via the network 206 may be performed over a cellular data connection or a WÎ-FÎ connection. Altematively, this can be performed with a wired connection or any other wired or wireless data transport mechanism.

In certain embodiments of the présent invention where a computing device, such as a smartphone or tablet, is utilized for authenticating an item, a software application may be used to simplify the authenticatîon process. Figure 3 shows a smartphone with an exemplary screen shot of a software application that may be utilized for authenticating an item. The exemplary application may be configured to be executed on any mobile platform, such as Apple's iOS or

Google's Android mobile operating system. When the application is run, the software application may provide instructions to a user ou properly irradiating or exciting the doped security thread and scanning, imaging, and/or detecting the spectrum produced from the doped security thread. Once the irradiating and scanning of the doped security thread is complété, the application may facilitate comparison of the measured spectral signature or the measured code 20 with a database that stores certain reference codes or spectral signatures to authenticate the item. Further, the application may provide a message or other indicator informing the user of the resuit of the authenticatîon. For example, the application may provide a text, graphical, or other visual indicator on the screen of the smartphone showing the results of the authenticatîon.

Alternatively, the application may provide audible and/or tactile indicators conveying the results of the authenti cation.

The embodiments and examples above are illustrative, and many variations can be introduced to lhem without départi ng from the s pi rit of the disclosure or from the scope of the 5 appended daims. For example, éléments and/or features of different illustrative and exemplary embodiments herein may be combined with each other and/or substituted with each other within the scope of this disclosure. For a better understanding of the invention, its operating advantages and the spécifie objects attained by its uses, reference should be had to the accompanying drawîngs and descriptive matter in which there are îlhistrated exemplary 10 embodiments of the invention.

Claims (22)

1. I. A method for authenti cation, comprising:

   irradiating an item including a polymer security thread comprising a polymer material and a doping material within the polymer material and configured to produce a radiation spectrum in response to the irradiating, the doping material capable of absorbing, scattering, or emitting radiation; and detecting the produced radiation spectrum to confirm the presence of the polymer security th read.
2. 2. The method of claim 1, wherein the produced radiation spectrum is a spectral signature distinct from a spectrum of the irradiating.
3. 3. The method of claim 2, further comprising detecting the spectral signature in the produced radiation spectrum, and determining a code associated with the spectral signature.
4. 4. The method of claim 3, further comprising comparing the determined code to a reference code; and providing an indication of authenti ci ty if the determined code match es the reference code.
5. 5. The method of claim 2, wherein the spectral signature is an absorption or scattering pattern in the produced radiation spectrum.
6. 6. The method of claim 5, wherein the produced radiation spectrum includes visible light.
7. 7. The method of claim 5, wherein the produced radiation spectrum includes non-visible

   5 electromagnetic radiation.
8. 8. The method of claim 2, wherein the doping material is capable of absorbîng, scattering, or emittîng radiation at a plurality of spécifie wavelengths to produce the spectral signature.

   iO
9. 9. The method of claim 8, whereîn the absorbed, scattered, oremitted radiation at the plurality of spécifie wavelengths has different intensities at each of the plurality of spécifie wavelengths.
10. 10. The method of claim l, whereiri the polymer security thread has a thickness of 5 to 70 microns.
11. 11. The method of claim 1, wherein the polymer security thread is disposed in or on a sub strate.
12. 12. The method of claim 11, wherein the substrate is a paper substrate or a composite 20 polymer-paper substrate.
13. 13. The method of claîm 11, wherein the polymer security thread is a single layer within the substrate, is disposed between two layers, or is windowed in the substrate in an alternating m anner.
14. 14. The method of claim 13, wherein the polymer security thread is disposed between two layers, and wherein each of the two layers includes a phosphor.
15. 15. The method of claim 1, wherein the item is currency.
16. 16. A system for authenticatîon, comprising:

    a radiation source for irradiating an item including a polymer security thread comprising a polymer material and a doping material within the polymer material and configured to produce a radiation spectrum in response to the irradiating, the doping material capable of absorbing, scattering, or emitting radiation; and a sensor configured to detect die produced radiation spectrum to confirm the presence of the polymer security thread.
17. 17. The system of claim 16, wherein the polymer security thread has a thickness of 5 to 70 microns.
18. 18. The system of claim 16, wherein the polymer security thread is disposed in or on a substrate.
19. 19. The system of claim 18, wherein the substrate is a paper substrate or a composite polymer-paper substrate.
20. 20. The system of claim 18, wherein the polymer security thread is a single layer within the 5 substrate, is disposed between two layers, or is windowed in the substrate in an alternating manner.
21. 21. The system of claim 20, wherein the polymer security thread is disposed between two layers, and wherein each of the two layers includes a phosphor.
22. 22. The system of claim 16, wherein the sensor includes an imaging device of a smartphone or a tablet.