Patent Application
20100089804
1. Field of the Invention
The present invention concerns a method for authenticating objects or substances using chemical marking or tracing. It applies more particularly but not exclusively to the fight against counterfeiting, to automatic sorting and also to make quality control and to have traceability of materials comprising recycled materials.
2. Description of the Prior Art
As a general rule, numerous objects or substances whether in transit or on sale are identified by means of a bar code. With this code it is possible to define products but it is not sufficient for their authentication i.e. for certifying after analysis that the object or substance is indeed the one defined by the bar code.
In an attempt to solve this problem, methods integrating a chemical marker into objects or substances have been developed. However, it is necessary to have recourse to laboratories to perform analyses and detect counterfeited products: this procedure is far too time-consuming and laborious.
As for the solution which consists of developing analytical equipment specific to each product, this solution is not economically viable.
The object of the invention is to solve these drawbacks by proposing that only one apparatus is used for a multiplicity of products.
For this purpose, it proposes an authentication method for different objects or substances to be identified, comprising at least the two following successive phases:
In this method, the spectrophotometric analysis phase may comprise the following steps:
Advantageously, the determination of the spectrum zones to be analysed, and of the different parameters allocated to each of these zones, may be made by the system using the identification data. This solution provides improved reliability of results and considerably reduces the required power of processing means.
The parameters relating to the presence or absence of markers in the allocated combination and used for determining an identification and/or authentication code particularly comprise:
To increase the number of possible combinations, different concentrations of markers may be used to obtain rays of different intensity.
Also, to overcome any optical factors likely to disturb the reading and subsequent spectrophotometric analysis, the invention proposes two measures which may be used separately or in combination.
The first measure consists of servo-controlling the light intensity emitted by the light radiation generator in relation to the difference between the value of the light intensity detected over a predetermined frequency range that is not affected by the presence of the markers, and a predetermined set value.
The second measure consists of incorporating in the object and/or substance one or more calibration markers used by the computer system for correction or calibration purposes so as to overcome noise derived for example from the composition of the substance or object, from variations in positioning such as angle of incidence and distance to the object, or from transparent matter surrounding this substance or object.
These two measures prove to be essential when several intensity levels are used as parameters.
According to one variant, chemical marking may be made via a label, an insert or any other medium containing the marker or markers.
Advantageously, this label may comprise a reflective zone coated with a transparent layer containing markers. With this solution it is possible to conduct reflection spectrophotometry which considerably reduces energy losses.
The authentication data may comprise the combination of chosen markers, the wavelengths of characteristic rays, their intensity, possible fluorescence time . . . .
It is therefore not necessary to cover all wavelengths, it is sufficient to analyse the ranges of values corresponding to the expected rays which are identified using the identification code in order to verify their presence or absence without taking into account the zones located outside these ranges.
To conduct authentication, the operator performing the analysis does not need to know the theoretical identity of the object or substance since it is provided by the bar code directly to the computer system performing data comparison.
Reading of identification code as well as authentication code can be done simultaneously at several levels with the manufacturer signature and an identification of the type or the grade of the material.
Said method may be used in the fight against counterfeiting, but may also be applied to automatic sorting. For example, when recycling plastic, it could be considered to use a combination of markers per type of plastic or per grade of plastic enabling subsequent sorting per type or per grade once authentication has been carried out.
In this method the coding and identifying steps can be coupled to pattern recognition step.
Furthermore, it can be useful to code several types of information concerning a substance or an object, for instance its composition, its recycling process, its maker . . . . There is as well the problem of black or strongly coloured substances or objects which are relatively frequent.
Coloration is due to the presence within the substance of colored pigments, notably carbon black, in variable proportions. Carbon black is used as a protective agent against radiations, mainly UV radiation, in outdoor applications or as a stabilizing and strengthening agent. Its action mainly consists of absorbing the radiations received by the substance which may cause degradations of the polymeric chains. However, it also has the property of absorbing radiations which may be notably emitted in the visible spectrum by the substance making up the object and/or the markers incorporated in the substance, which explains its dark or black color. The result of this is that excitation by a light source does not cause any spectral emission allowing easy extraction of information relating to the substance with very small concentrations of markers if it is strongly colored or black.
It is therefore an aim of the invention to solve these problems thanks to a method for identifying and authenticating substances or objects independently of their colours and with very low concentrations of markers, by proposing a method comprising the following steps:
The method consists of subjecting a substance or an object to a combination of different excitation vectors and not only to a light excitation. The excitation vectors may be applied either simultaneously or sequentially.
Advantageously, the method may be preceded by a phase comprising:
In this preliminary phase, at least one marker is selected which may be incorporated into substances, for example plastic materials, at a very low concentration, each marker Si having a response Ri,j to an excitation vector Vj. Each marker does not have to respond to each excitation vector, it is sufficient that it responds to at least one excitation vector.
In the most current case, a marker Si responds to the excitation vector Vi and there are as many substances as there are excitation vectors. However two markers may respond to the same excitation vector provided that their responses are distinct, for example in fluorescence, at different wavelengths. The number of markers used in a substance may therefore be larger than the number of excitation vectors. Conversely, the number of markers may be less than the number of excitation vectors in the case when one or more markers would respond to different excitation vectors. Multiplication of the excitation vectors has the benefit of allowing resorting to wider families of substances and therefore broadening the coding ability of the method.
The very small concentration used for the markers is essential:
The markers may be embedded into the bulk or positioned at the surface, for example by impregnation (for example in a textile, a tincture . . . ), by coating (varnish, paint coating, spraying) on various supports, for example aircraft metal parts, whether this be on the whole of the surface or punctually (screen-printing, brush plating) or as marked labels either partly visible or not. Advantageously, this coating may comprise a reflecting area covered with a transparent layer containing markers. With this technique, it is thereby possible to carry out spectrophotometry by reflection which considerably reduces the energy losses.
As the responses of the markers to the different excitation vectors are known, it is possible to elaborate a correspondence table between combinations of markers and therefore responses to excitations and information provided for the substances in which they will be incorporated. For example, if three substances S1, S2 and S3 and two excitation vectors V1 and V2 are used and if:
More generally, the use of n marking substances in a material (n≧1), subject to p excitation vectors (p≧2), in order to obtain r responses (r≧n*p) enables a correspondence table to be constructed with 2r−1 inputs, and therefore to be coded with as many pieces of information relating to the substance.
This may therefore result in a great possibility of coding information relating to a substance or to an object incorporating these substances by multiplying the excitation vectors and the markers.
In the step for determining information relating to said substance or to said object:
The excitations to which the substance is subject cause one or more responses. These responses are matched with the correspondence table between expected responses and information concerning the substance, which for example enables identification of this substance. If no response is obtained, or if the obtained response does not appear in the correspondence table, it will not be possible to allocate information concerning the substance.
In a step for elaborating the correspondence table, it is possible to only take into account the presence or the absence of a marker response to the excitation vectors, and/or the intensity of a marker response, for example as a plurality of response thresholds.
The spontaneous emission of a selected marker in the absence of any excitation vector may also be taken into account, for example in the form of spontaneous emission of electromagnetic radiation or particles, either neutral or charged particles, notably in the case of radioactivity, or of emission of molecules, notably odorous molecules.
Advantageously, in the detection step, it is possible to take into account the emission of the material under the effect of the excitation vectors, notably for correcting the obtained responses, for example for subtracting background noise.
A large number of excitation vectors may be contemplated:
Advantageously, the provided responses from the markers and the obtained responses are selected from the list comprising:
As indicated above, these responses are remotely detectable.
Advantageously:
Yttrium vanadate doped with europium, excited between 230 and 390 nm, i.e. in the near UV, used alone or in combination with other markers, provides a response centered on 610-620 nm which may exploited in black or strongly colored substances.
When a black or strongly colored substance is excited in the near UV, a relatively large background noise is observed, which requires signal processing, for example in order to form a baseline, so as to extract and quantify the responses. When yttrium vanadate doped with europium is used in combination with another marker, one of them may be used as a calibration, one then operates differentially.
With the method, it is possible to collect one or more pieces of information relating to a substance or an object, for example a chemical property, notably its chemical composition and therefore identify the material being examined or its quality (type, grade). The information may also relate to the manufacturing of the substance or of the object, for example the identity of its manufacturer, its location or its manufacturing date . . . .
Thus, a transition is performed from simple identification of a material or of an object to its authentication, i.e. the possibility of distinguishing an authentic object from a non-authorized copy, for example within the scope of the struggle against counterfeiting.
By its generality, the method is applicable to any types of substances, notably black or strongly colored substances, which absorb a large range of radiations.
In the case of an excitation by a light beam, the identification data may comprise the combination of selected markers, the wavelength of the characteristic radiation lines, their intensity, the duration of possible fluorescence . . . .
Thus, it is unnecessary to observe all the wavelengths emitted by the substance, it is sufficient to analyze the ranges of values corresponding to the lines provided in the correspondence table, stored in memory beforehand, in order to check their presence or their absence without being concerned with the zones located outside these lines.
The identification code may result from a combination of markers and may consist in a binary number, the binary figures of which each correspond to the presence or the absence of a marker.
In the case of an identification with view to recycling substances, the use of this combination of markers may be contemplated in order to code the type or the grade of substances, for example plastic materials, which enables them to be sorted per type or per grade once identification is achieved. The code may also relate:
By extension, by combining several excitation vectors and markers it is possible to obtain several pieces of information of different nature on a material, for example the authentication of one or more actors during the life cycle of a substance or of an object (manufacturer, distributor, owner . . . ); for this purpose, it is sufficient that the substance incorporated into the object has been marked beforehand depending on one or more actors involved in the life cycle of a substance or of an object and not only on its composition.
The method is applied to the identification of any type of substance, notably substances with any more or less dark coloration; it is particularly applicable to the identification of colored or black substances.
Embodiments for implementing the invention are described below as non-limitative examples.
In the example in
It is to be noted that this type of analysis can also be made on objects whose substance so permits, or directly on the substance through its recipient.
In this example the identification and authentication device using the method of the invention comprises a spectrophotometer comprising:
As mentioned previously, the light source 4 is a source with wide frequency spectrum. It may consist of arc lamps (Xenon type) or of a light bulb generating a white light. Optionally, it may consist of a plurality of laser radiation sources specifically chosen in relation to the type of the chemical markers used, a mixer then being used to mix the different radiations emitted by these sources.
The lens 5 may for example consist of an achromatic doublet.
Evidently, the electric current generator 6 may also be used to supply the electronic circuits associated with the spectrophotometer.
In this example, the detector array 3 comprises a cell C located at a position of the spectrum that is not affected by the presence of chemical markers.
This cell C emits a detection signal applied (after amplification) to the input of a subtractor S whose second input receives a calibrated voltage VC. The output of this subtractor S is applied to a power amplifier AP which pilots the generator 6 so that the output of the subtractor S is maintained at a constant value, preferably equal to zero.
With this arrangement, it is ensured that the level of light intensity received by cell C is constant. This overcomes disturbances which may cause variations in the light intensity of the radiation transmitted through sample 8.
According to the invention, the light source is associated with a bar code reader 12 which emits light radiation (laser for example) in the direction of a bar code 11 carried by recipient 9. This reader 12 comprises a receiver enabling detection of the radiation reflected by the bar code. An electronic circuit processes the data received by this receiver and generates a digital signal representing this bar code to be sent to the electronic system E.
The electronic system comprises a processor P (indicated by the dashed line) associated with means for memorising a database of identification codes BC, a database of authentication codes BA and a management program for the various processing operations PG, and with display and signalling means AF.
This processor P is designed so as to conduct theoretical identification (block B1) of recipient 9 using the signal delivered by the bar code reader 12, from the database of identification codes BC. Once theoretical identification has been made, processor P determines the spectrum zones to be investigated (block B2). For this purpose, in addition to the readout identification code, it uses the corresponding authentication code by means of a correspondence table TC between the two databases BC, BA. The processor P then analyses (block B3) the spectrum zones previously determined through the signal provided by the detector array 3.
If a calibration marker is used, this signal may be corrected (block B4) before analysis using the digital signal produced by the detector corresponding to this calibration marker.
The processor P then determines (block B5) the detected authentication code which it compares (block B6) with the predetermined identification code. If there is agreement between these two codes, the processor emits a validation signal SV. If not, the processor emits an alarm signal SA.
The method of the invention used by the device illustrated
In this case, the dispersing element 1 is located on the axis of the reflected wave.
The method is the same as described above for the example in
The method is the same as described above for the example in
In addition, the use of a label free of any marker and optionally coated with a film or varnish used for applying markers may, when processing data, enable the elimination of corresponding signals and simplify analysis. The marked label then the blank label are irradiated after which, during data processing, the spectrum data of the blank label are subtracted from the spectrum data for the marked label.
When fluorescent markers are used, it can be considered to conduct a second measurement after a time δt to verify fluorescence time.
The tracers used may be organic or inorganic. They may contain rare earths such as dysprosium, europium, samarium, yttrium . . . .
Some markers used and their characteristics are given as examples in the table below.
They are commercially available from companies such as BASF, Bayer, Glowburg, Lambert Rivière, Phosphor Technology, Rhodia, SCPI, . . . .
It is to be noted that the markers are not limited to commercially available markers, they may be synthesized by total synthesis or derived from commercial markers.
It is seen:
Taking into account the lower intrinsic response of these substances in the red and near IR domain on the one hand and the uniformly low response of the black-pigmented substance, it is inferred therefrom that it may be advantageous to use markers which, after irradiation of the marked object or substance, emit radiations in a frequency band corresponding to red—near infrared.
Advantageously, markers will be selected which have a response in the range from 500 to 650 nm.
Taking into account the Stokes shift, the irradiation should take place in a range of smaller wavelengths, for example in the near UV, in the 220-380 nm range.
The markers used may be chemical, organic or mineral, or consist of nanoparticles. These may be products made on demand or commercial products.
For example, markers marketed by “Phosphor Technology Dyes” (registered trade name) may be used, the characteristics of which are the following:
These markers further have the advantage of exhibiting good thermal and chemical stability, as well as good UV-fastness.
In order to obtain signals with which the substance will be identified:
| Number | Date | Country | Kind |
|---|---|---|---|
| 0213718 | Oct 2002 | FR | national |
This application is a Continuation-in-Part of application Ser. No. 10/533,356 filed Apr. 29, 2005, which is National Stage of PCT/FR2003/003233, filed Oct. 29, 2003, which claim priority to French application No. 0213718, filed Oct. 29, 2002. The entire content of all three applications are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | 10533356 | Apr 2005 | US |
| Child | 12557774 | US |
