GB2567178A

GB2567178A - Improvements in and relating to security documentation

Info

Publication number: GB2567178A
Application number: GB1716224.9A
Authority: GB
Inventors: David Reynolds Neill
Original assignee: Inovink Ltd
Current assignee: Inovink Ltd
Priority date: 2017-10-05
Filing date: 2017-10-05
Publication date: 2019-04-10
Also published as: GB201716224D0

Abstract

A detector 1 for verifying the authenticity of an article 200, wherein the article carries an ink composition 210 which exhibits non-uniform absorption of radiation in the infra-red range, comprising: an infra-red transmitter to transmit two wavelengths of IR light, a receiver to receive the response of the transmitted light upon returning from the article and a processor to measure and calculate the difference between the amplitudes of the received signals and to indicate authenticity if the amplitude difference is above a predefined threshold. The difference between the two received signals may involve subtraction (and returning the modulus of the result) or forming a ratio of the two signals. The threshold may be based on a percentage difference between the signals. The detector may be designed for handheld use, may have an audio 10, visual 20, 30 or haptic feedback device for indicating authentication.

Description

The present invention relates to a device for detecting a security feature associated with an item. It particularly relates to a security feature applied to or incorporated into a banknote or similar item of value. More particularly, it relates to a handheld detector for use, typically, by a retailer to verify the authenticity of a banknote.

Banknotes are routinely provided with one or more security features to deter counterfeiters and to enable recipients of the banknotes to verify their authenticity, or otherwise. Such features typically include watermarks, embossing, intaglio printing, microprinting or holograms. These techniques are visible to the human eye and are relatively easy to check. However, hidden security features, invisible to the human eye, are increasingly used and provide additional security. Such features include printing onto the banknote with a specialised ink which is only visible under light of a certain wavelength e.g. ultraviolet.

In the Applicant’s co-pending application WO2016/135452, details of an improved security printing article and method.

In essence, the co-pending application WO2016/135452 discloses an ink which exhibits a particular response to infra-red radiation. Specifically, the ink exhibits non-uniform absorption behaviour when exposed to infra-red radiation of different, defined, frequencies. In particular, it discloses an ink which exhibits a first absorption at a first wavelength and a second, different, absorption at a second wavelength.

It is an aim of embodiments of the present invention to provide a detector for authenticating an article broadly as described in WO2016/135452.

According to the present invention there is provided an apparatus and method as set forth in the appended claims. Other features of the invention will be apparent from the dependent claims, and the description which follows.

According to a first aspect of the invention, there is provided a detector for verifying the authenticity of an article, wherein the article carries an ink composition which exhibits nonuniform absorption of radiation in the infra-red range, wherein the detector comprises: an infrared transmitter arranged to transmit a first signal at a first wavelength and to transmit a second signal at a second wavelength; an infra-red receiver arranged to receive first and second received signals in response to the first and second transmitted signals, respectively; a processor arranged to measure the amplitude of the first and second received signals and to calculate the difference between them; the processor being further arranged to indicate the authenticity of the article if the calculated difference exceeds a predefined threshold.

Suitably, a further threshold may be employed such that in order to be judged as authentic, the calculated difference must exceed a first threshold and be below a second threshold i.e. the calculated difference must fall within a defined range. This can prevent the occurrence of false positives, where a received signal overloads the infra-red receiver, for instance.

Suitably, the processor is arranged to calculate the difference between the first and second received signals by subtracting the amplitude of the first received signal from the amplitude of the second received signal and comparing the calculated result with the predefined threshold.

Suitably, the processor is arranged to compare the modulus of the calculated result with the predefined threshold.

Suitably, the processor is arranged to calculate the difference between the first and second received signals by calculating a ratio of the first and second received signals and comparing the calculated result with the predefined threshold.

Suitably, the predefined threshold corresponds to a predefined percentage difference between the amplitudes of the first and second received signals.

Suitably, the infra-red transmitter comprises first and second emitters for transmitting the first and second signals respectively.

Suitably, the first emitter is operable to transmit at the first wavelength and the second emitter is operable to transmit at the second wavelength.

Suitably, the first wavelength is in the range 750nm - 850nm and the second wavelength is in the range 950nm - 1000nm.

Suitably, the infra-red receiver comprises a single detector arranged to receive the first and second received signals in response to the first and second transmitted signals, respectively.

Suitably, the infra-red receiver is one of: a photodiode; a phototransistor; a CCD IC; and a CMOS detector IC.

Suitably, the first and second transmit signals are in the form of a pulse train comprising a plurality of‘on’ and ‘off pulses.

Suitably, the detector is handheld and is arranged to be brought into close proximity to the article by a user.

Suitably, the detector comprises a visual indicator, operable in at least two states, to indicate whether the article has been verified as authentic or not.

Suitably, the detector comprises an audio output device, operable to output at least two different sound output signals, to indicate whether the article has been verified as authentic or not.

Suitably, the detector comprises a haptic feedback device, operable to indicate whether the article has been verified as authentic or not.

Suitably, the detector comprises an interface for connection to an external device.

Suitably, the interface is arranged to connect to one or more of: an external processing device for updating software or firmware provided in the detector; an external processing device arranged to download stored data from the detector; and a charging device for charging an internal battery of the detector.

According to a second aspect of the invention, there is provided a method of verifying the authenticity of an article, wherein the article carries an ink composition which exhibits nonuniform absorption of radiation in the infra-red range, comprising the steps of: directing at the article, radiation at a first wavelength and measuring an amplitude of a first reflected signal; directing at the article, radiation at a second wavelength and measuring an amplitude of second reflected signal; calculating a difference between the amplitudes of the first and second reflected signals; and indicating the authenticity of the article if the calculated difference exceeds a predefined threshold.

According to a third aspect of the present invention, there is provided a kit comprising the detector according to the first aspect and further comprising a sample article, selectively printed with an ink composition which exhibits non-uniform absorption of radiation in the infrared range.

Although a few preferred embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims.

Fora better understanding of the invention, and to show how embodiments of the same may be carried into effect, reference will now be made, by way of example only, to the accompanying diagrammatic drawings in which:

Figure 1 shows a schematic block diagram of certain elements of a detector according to an embodiment of the present invention;

Figure 2 shows a conceptual representation of a detector according to an embodiment of the present invention; and

Figure 3 shows a flowchart setting out certain steps in a method of operation of a detector according to an embodiment of the invention.

Figure 1 shows a schematic block diagram of certain functional units which make up a detector according to an embodiment of the invention.

The detector 1 is contained in a handheld housing, (shown conceptually in Figure 2), and includes several functional units. At the heart of the detector 1 is a processing unit 100 which controls the operation of the device. The processing unit may be an off the shelf microprocessor or microcontroller or it may be a custom IC, such as an ASIC or other form of programmable logic device. The processing unit 100 is operable to run program code, which is stored in memory 110. Memory 110 may comprise a permanent store and a transient store, where the permanent store is for storing program code and other data such as calibration data, and the transient store is working memory for use by the processing unit 100 during normal operation of the device.

Power is provided to the detector 1 from an internal power source 120. The internal power source is a rechargeable battery, preferably of the Lithium-ion type, which has a relatively high charge capacity and so can provide relatively long periods of use between charges. Alternatively, the internal power source may be a replaceable battery. In a further embodiment, the detector 1 may be powered from an external power source.

The power source 120 provides all power to all functional units in the detector. The internal power source may be recharged via interface 160, which will be described later.

The processing unit 100 is connected to an infra-red transmitter 130 which is operable to transmit radiation in the infra-red range. In particular, it is operable to transmit radiation at two specific wavelengths. There is provided a separate emitter for each of the two wavelengths, with each emitter being tuned or otherwise arranged to operate at each of the specific wavelengths. In a preferred embodiment each emitter is a Light Emitting Diode (LED), with one arranged to transmit in the range 780nm - 850nm and the other arranged to transmit in the range 950nm to 1000nm.

The processing unit 100 is further connected an infra-red receiver 140. The infra-red receiver is arranged to receive signals in response to the signals transmitted from the infra-red transmitter 130, which are reflected back from the target substrate. The infra-red receiver 140, in a preferred embodiment, is a single photo-diode operable to have an equal response to signals received at the two separate transmit wavelengths. It is preferably a photo-diode. It may alternatively be a phototransistor, a CCD IC, or a CMOS detector IC.

In a preferred embodiment, the two separate emitters which make up the transmitter 130 are configured such that reflections from a target which does not include the ink which exhibits non-uniform IR absorption, such as an inauthentic article or even a blank piece of paper, are equal when received at the IR receiver 140. This may require each emitter to be provided with a different operating power. The possibly different operating powers are stored as configuration data. In this way, any deviation from an equal response to transmissions of each wavelength may be measured and used as a basis to determine if the target article is authentic or not.

Alternatively, the two emitters may be configured with the same operating power, producing possibly different measures responses in the IR receiver. The processing of the received signals would then take into account this inherent difference when comparing the magnitude of the received signals.

The processing unit 100 is connected to an output unit 150, which is operable to provide indications to a user of the result of an authentication procedure. The output unit comprises a visual indicator and an audio indicator. One or both of these may be used to provide a visual or audible indication of the result of the authentication.

The visual indicator comprises a pair of LEDs 20, 30 (as shown in Figure 3). One LED 20 is green and indicates a successful authentication (i.e. the article being authenticated is genuine) and the other LED 30 is red and indicates an unsuccessful authentication (i.e. the article being authenticated is not genuine or suspect).

The pair of LEDs 20, 30 may be replaced with a single device operable to illuminate red or green.

The audio indicator 10 is a small speaker, buzzer or other audio device which creates a first tone or sound associated with a successful authentication and a second tone or sound associated with an unsuccessful authentication.

The processor 100 is connected to interface unit 160, which allows the device 1 to be connected to an external device for various purposes. The external device may be an external data processing device, such as a desktop or laptop computer or tablet device. It may also be a charger for charging the internal power source 120. The interface may use any commonly available connector and standard. A suitable interface standard is USB and the device may be equipped with a suitable connector for receiving a cable for onward connection to the external device. Alternatively, another form of connector, including a custom connector, may be used.

When connected to the charger, perhaps at the end of a working day, the internal power source 120 is recharged, ready for use in a wireless fashion. When connected to an external data processing device, the device 1 may be set up or monitored by use of a custom application running on the external data processing device. The custom application can also set up the operation of the device so that user preferences for the output unit 150 can be assigned as required.

The custom application can also monitor and collect data on the operation of the device 1. For instance, the number of successful or unsuccessful authentication operation performed in a given time can be monitored. This may provide an indication that a particular device is malfunctioning and/or needs re-calibrating.

Figure 2 shows a representation of the device 1, in use, authenticating an article 200. The device 1 is a handheld device having a housing in which is situated all the circuitry of the device. Externally, there are a number of items which enable the device to be used in a straightforward, intuitive manner.

In use the device 1 is introduced to the article 200 to be authenticated. This may be a banknote or other document or article. On the article, there will be one or more particular areas 210 which have been printed with the ink described previously, which has the specific infra-red absorption properties described. It will not generally be possible to tell with the naked eye where on the article the area 210 is located and so the user will require some information on where to position the device 1. On a banknote, for instance, the area 210 may be located consistently in a certain part of a face, in a number or other easily located feature.

The device 1 is then located on or very near the area 210 so that the face 50 of the device is touching or very nearly touching the area 210. The infra-red transmitter 130 and receiver 140 are housed inside the detector body and signals from and to them pass through the face 50.

The user then operates the control 40 which commences the authentication procedure, as described in relation to Figure 3. The control 40 is a simple switch which powers up the device and commences the authentication procedure.

If the result of the authentication is positive and the article 200 is genuine, then green LED 20 is illuminated and a ‘success’ tone is generated and played from speaker 10. If, conversely, authentication is negative, then red LED 30 is illuminated and a ‘failure’ tone is generated and played from speaker 10. The device may additionally include a haptic feedback device, such as a vibrating element. The vibrating element may be operable to vibrate if the article is judged to be authentic or it may have two vibration patterns, each associate with success or failure.

More detail of the authentication procedure is provided in connection with Figure 3 which shows a detailed flowchart, setting out a mode of operation of the device 1 in normal use.

Operation begins as S100 when a user picks up the device 1, positions it on or near the area 210 of the article 200 and operates switch 40.

At step S110, the infra-red transmitter 130 transmits a pulse train at the first wavelength λ1, which is preferably 850nm. The pulse train takes the form of a series of on pulses of approximately 100ps duration, each separated by an off period of approximately 60 ps duration. Suitably, 20 pulses are transmitted in each cycle.

At step S120, the infra-red receiver 140 is operable to receive signals in response to the transmission of step S110. Although shown in sequence, in practice, the receiver 140 is operable simultaneously with the transmitter to receive signals immediately in response to the transmission. The receiver 140 is physically located so that it does not receive any direct radiation from the transmitter 130 and only receives signals reflected from the article 200.

At step S130, the infra-red transmitter 130 transmits a pulse train at the second wavelength λ2, which is preferably 950nm. The pulse train takes the form of a series of on pulses of approximately 100ps duration, each separated by an off period of approximately 60 ps duration. Suitably, 20 pulses are transmitted in each cycle.

At step S140, the infra-red receiver 140 is operable to receive signals in response to the transmission of step S130. Although shown in sequence, in practice, the receiver 140 is operable simultaneously with the transmitter to receive signals immediately in response to the transmission.

At step S150, the processing unit 100 is operable to calculate a ratio ofthe amplitudes ofthe signals received in steps S120 and S140. Since the degree of absorption ofthe area 210 is non-uniform, it is expected that in a genuine article, the signals received in response to transmissions at the two wavelengths λ1 and λ2, for the same transmit power will be different in a deterministic manner. As such, the processing unit is able to calculate the ratio ofthe two received amplitude values. By calculating a ratio in this way, the absolute values of the received signals is unimportant. However, in an alternative embodiment, it may be preferred to use absolute values. In this case, the processing unit 100 is operable to calculate a difference between the two values. It may further take the modulus of this value to ensure a positive result is always obtained.

At step S160, the calculated ratio is compared with a predetermined threshold. The threshold is determined to provide a sufficient degree of confidence that the article 200 is genuine. For instance, the threshold may be determined such that the difference between the first and second received signals is greater than 10%. In other words, the amplitude of the second received signal must be at least 1,1xthe amplitude ofthe first received signal in order for the article to be judged authentic.

If the threshold is met or exceeded, then flow passes to S170, where the green LED 20 is illuminated and a success tone is generated and played.

However, if the threshold is not met, then flow passes to S180, where the red LED 30 is illuminated and a failure tone is generated and played.

After either of steps S170 or S180, the operation terminates at S190 and awaits recommencement as required.

Embodiments of the invention allow the authenticity or otherwise of an article to be tested in a straightforward and intuitive manner which provides an easily understood binary result - authentic or suspect. If the result is authentic, then a user can take whatever further steps may be necessary. In a typical retail setting, the banknote in question can be accepted and the transaction can be completed. If the banknote is found to be suspect, then it may be declined and further steps may be taken.

Since, typically, only a portion 210 of the article 200 is printed with the ink composition which exhibits non-uniform infra-red absorption, a small amount of user training is required so that the user knows where on the article to position the device 1 in use. In order to familiarise users with the operation of the device, it may be supplied with one or more sample articles, selectively printed with the ink composition which exhibits non-uniform infra-red absorption, to allow the users to experiment with the operation of the device and familiarise themselves with the process, without having to use actual banknotes.

At least some of the example embodiments described herein may be constructed, partially or wholly, using dedicated special-purpose hardware. Terms such as ‘component’, ‘module’ or ‘unit’ used herein may include, but are not limited to, a hardware device, such as circuitry in the form of discrete or integrated components, a Field Programmable Gate Array (FPGA) or Application Specific Integrated Circuit (ASIC), which performs certain tasks or provides the associated functionality. In some embodiments, the described elements may be configured to reside on a tangible, persistent, addressable storage medium and may be configured to execute on one or more processors. These functional elements may in some embodiments include, by way of example, components, such as software components, objectoriented software components, class components and task components, processes, functions, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuitry, data, databases, data structures, tables, arrays, and variables. Although the example embodiments have been described with reference to the components, modules and units discussed herein, such functional elements may be combined into fewer elements or separated into additional elements. Various combinations of optional features have been described herein, and it will be appreciated that described features may be combined in any suitable combination. In particular, the features of any one example embodiment may be combined with features of any other embodiment, as appropriate, except where such combinations are mutually exclusive. Throughout this specification, the term “comprising” or “comprises” means including the component(s) specified but not to the exclusion of the presence of others.

Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or steps are mutually exclusive.

Each feature disclosed in this specification (including any accompanying claims, abstract and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or 10 similar features.

The invention is not restricted to the details of the foregoing embodiments). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, 15 or any novel combination, of the steps of any method or process so disclosed.

Claims

1. A detector for verifying the authenticity of an article, wherein the article carries an ink composition which exhibits non-uniform absorption of radiation in the infra-red range, wherein the detector comprises:

an infra-red transmitter arranged to transmit a first signal at a first wavelength and to transmit a second signal at a second wavelength;

an infra-red receiver arranged to receive first and second received signals in response to the first and second transmitted signals, respectively;

a processor arranged to measure the amplitude of the first and second received signals and to calculate the difference between them;

the processor being further arranged to indicate the authenticity of the article if the calculated difference exceeds a predefined threshold.

2. The detector as claimed in claim 1, wherein the processor is arranged to calculate the difference between the first and second received signals by subtracting the amplitude of the first received signal from the amplitude of the second received signal and comparing the calculated result with the predefined threshold.

3. The detector as claimed in claim 2 wherein the processor is arranged to compare the modulus of the calculated result with the predefined threshold.

4. The detector as claimed in claim 1, wherein the processor is arranged to calculate the difference between the first and second received signals by calculating a ratio of the first and second received signals and comparing the calculated result with the predefined threshold.

5. The detector as claimed in claim 4 wherein the predefined threshold corresponds to a predefined percentage difference between the amplitudes of the first and second received signals.

6. The detector as claimed in any preceding claim wherein the infra-red transmitter comprises first and second emitters for transmitting the first and second signals respectively.

7. The detector as claimed in claim 6 wherein the first emitter is operable to transmit at the first wavelength and the second emitter is operable to transmit at the second wavelength.

8. The detector as claimed in any preceding claim wherein the first wavelength is in the range 750nm - 850nm and the second wavelength is in the range 950nm - 1000nm.

9 The detector as claimed in any preceding claim wherein the infra-red receiver comprises a single detector arranged to receive the first and second received signals in response to the first and second transmitted signals, respectively.

10. The detector as claimed in claim 9 wherein the infra-red receiver is one of: a photodiode; a phototransistor; a CCD IC; and a CMOS detector IC.

11. The detector as claimed in any preceding claim wherein the first and second transmit signals are in the form of a pulse train comprising a plurality of‘on’ and ‘off pulses.

12. The detector as claimed in any preceding claim wherein the detector is handheld and is arranged to be brought into close proximity to the article by a user.

13. The detector as claimed in any preceding claim wherein the detector comprises a visual indicator, operable in at least two states, to indicate whether the article has been verified as authentic or not.

14. The detector as claimed in any preceding claim wherein the detector comprises an audio output device, operable to output at least two different sound output signals, to indicate whether the article has been verified as authentic or not.

15. The detector as claimed in any preceding claim wherein the detector comprises a haptic feedback device, operable to indicate whether the article has been verified as authentic or not.

16. The detector as claimed in any preceding claim comprising an interface for connection to an external device.

17. The detector as claimed in claim 16 wherein the interface is arranged to connect to one or more of: an external processing device for updating software or firmware provided in the detector; an external processing device arranged to download stored data from the detector; and a charging device for charging an internal battery of the detector.

18. A method of verifying the authenticity of an article, wherein the article carries an ink composition which exhibits non-uniform absorption of radiation in the infra-red range, comprising the steps of:

directing at the article, radiation at a first wavelength and measuring an amplitude of a first reflected signal;

5 directing at the article, radiation at a second wavelength and measuring an amplitude of second reflected signal;

calculating a difference between the amplitudes of the first and second reflected signals; and

10 indicating the authenticity of the article if the calculated difference exceeds a predefined threshold.

19. A kit comprising the detector according to any of claims 1 to 17 and further comprising a sample article, selectively printed with an ink composition which exhibits non-uniform 15 absorption of radiation in the infra-red range.