Classifications

• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N21/87—Investigating jewels
• • A—HUMAN NECESSITIES
  • A44—HABERDASHERY; JEWELLERY
  • A44C—PERSONAL ADORNMENTS, e.g. JEWELLERY; COINS
  • A44C27/00—Making jewellery or other personal adornments
  • A44C27/001—Materials for manufacturing jewellery
  • A44C27/005—Coating layers for jewellery
  • A44C27/007—Non-metallic coatings
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
  • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
  • G01N21/64—Fluorescence; Phosphorescence
  • G01N21/6408—Fluorescence; Phosphorescence with measurement of decay time, time resolved fluorescence
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V20/00—Scenes; Scene-specific elements
  • G06V20/60—Type of objects
  • G06V20/66—Trinkets, e.g. shirt buttons or jewellery items
• • G—PHYSICS
  • G06—COMPUTING; CALCULATING OR COUNTING
  • G06V—IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING
  • G06V20/00—Scenes; Scene-specific elements
  • G06V20/80—Recognising image objects characterised by unique random patterns
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
  • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
  • G01N21/64—Fluorescence; Phosphorescence
  • G01N21/6428—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
  • G01N2021/6439—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" with indicators, stains, dyes, tags, labels, marks
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/62—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light
  • G01N21/63—Systems in which the material investigated is excited whereby it emits light or causes a change in wavelength of the incident light optically excited
  • G01N21/64—Fluorescence; Phosphorescence
  • G01N21/6428—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes"
  • G01N2021/6439—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" with indicators, stains, dyes, tags, labels, marks
  • G01N2021/6441—Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" with indicators, stains, dyes, tags, labels, marks with two or more labels
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
  • G01N21/84—Systems specially adapted for particular applications
  • G01N21/8422—Investigating thin films, e.g. matrix isolation method
  • G01N2021/8427—Coatings

Definitions

• Pearls used in jewelery are organo-carbonated biogenic concretions secreted by the mantle of molluscs. Pearlescent pearls are produced by bivalve molluscs either in freshwater or in seawater. There are 1) fine pearls - very rare on the market - formed without any human intervention, and 2) cultured pearls produced by grafting. outer mantle epithelium fragment with or without nucleus implantation. The production of cultured pearls concerns
• the thickness of mother-of-pearl produced around the nucleus is sufficient to allow harvesting.
• This thickness of mother-of-pearl is most often greater than 0.4 mm and for Tahitian pearls always greater than 0.8 mm (X-ray inspection). The pearls can therefore be marketed.
• the pearl jewelry market is estimated at $ 5 billion (10% of the global jewelery market), and there is strong competition between the various producing countries (Japan, Australia, French Polynesia, China) and finally, that processes of fitness, coloring, bleaching or even imitation develop, it is of extreme economic and strategic interest 1) to be able to control and guarantee the geographical origin, 2) to control and guarantee a quality based on commercial criteria (color, orient, luster, shapes, dimensions) and 3) to avoid any quality fraud, counterfeiting or treatment (artificial coloring by chemical agents, polishing ).
• Pearl pearls are fragile objects, luxury and whose external appearance is the main criterion of quality, actions on the surface such as laser engraving are difficult, and requires more individual marking delicate, long and expensive. It is also necessary not to modify the external optical appearance (orient and color) criterion on which is based partly the value of a pearl.
• the labeling of the nucleus before grafting either by a marker opaque to X-rays, or by another chemical marker, although infalsifiable and permanent since under the nacrière layer, this process also involves a long, complex and expensive individual marking.
• the present invention aims to satisfy at least one of the following objectives:
• the invention concerns first and foremost a method for marking a solid comprising at least one mother-of-pearl coating, said process comprising immersing said solid in an aqueous solution comprising a tracer. photoluminescent in the presence of said solid, for a time sufficient to obtain the fixing of said photoluminescent tracer to the mother-of-pearl coating.
• said solid is a pearly pearl, for example a pearl of culture, preferably produced by a pearl oyster, for example of the species Pinctada margaritifera.
• a plurality of solids are immersed simultaneously in the same bath of said aqueous solution, for example at least one hundred cultured pearls.
• Said tracer is preferably incorporated on the surface layer of the pearlescent coating to a thickness not exceeding 20 ⁇ , preferably at most 10 ⁇ .
• said photoluminescent tracer is chosen from those detectable by time resolved fluorescence in the presence of mother-of-pearl. Typically, it may be a rare earth ion, for example, a lanthanide. Among the lanthanides, said tracer may be chosen from Gd, Dy, Lu, Yb, Sm, Ho, Eu, Tb, Nd, Er, or mixtures thereof, for example a combination of Gd and Eu. In a particular embodiment, said aqueous solution comprises a combination of at least two photoluminescent tracers, which may be present in the same concentration or in different concentrations. The invention relates naturally to the solid comprising a nacre coating marked according to the marking method of the invention.
• the invention relates in particular to a pearlescent pearl comprising at least one tracer or a combination of photoluminescent tracers on the surface layer of the nacrière layer, for example to a thickness of at most 20 ⁇ of said surface layer, preferably at most 10 ⁇ , said photoluminescent tracer being detectable vis-à-vis the natural photoluminescence said pearl pearl.
• Said pearlescent pearl according to the invention comprises in particular a photoluminescent tracer which may be chosen from a rare earth ion, preferably a lanthanide, for example gadolinium, europium or their mixtures.
• a photoluminescent tracer which may be chosen from a rare earth ion, preferably a lanthanide, for example gadolinium, europium or their mixtures.
• the invention also relates to a method for identifying a labeled solid according to the invention or a pearlescent pearl according to the invention, characterized in that it comprises the time-resolved fluorescence detection of the photoluminescent tracer (s). .
• the identification method according to the invention is characterized in that it further comprises the detection of the absolute or relative amounts of a combination of photoluminescent tracers.
• Another aspect of the invention relates to the detection means suitable for implementing the identification method as defined above.
• These detection means may comprise, for example, a time resolved fluorescence detector and signal analysis means in order to identify the presence of the photoluminescent tracer (s) in the labeled solid or pearl pearl.
• the invention also relates to the use of detection means above, for tracing and / or identification of the origin of production and / or the quality of a pearly pearl.
• P.4.4.4.4. of. marking of a solid comprising. at least one mother-of-pearl coating
• the marking method according to the invention judiciously uses the particular structure of the mother-of-pearl, an organomineral hybrid matrix to fix photoluminescent elements thereupon detectable by appropriate means.
• the invention relates to a method of marking a solid comprising at least one mother-of-pearl coating, said process comprising immersing said solid in an aqueous solution comprising a photoluminescent tracer in the presence of said solid, during a sufficient time to obtain the fixation of said photoluminescent tracer within the mother-of-pearl coating.
• the solid comprising a rey of. nacre
• the marking process is applicable to any solid as it has an outer layer or a coating of nacre.
• Mother-of-pearl is the lining of some mollusc shells, composed of crystals of aragonite and conchyoline, with iridescent reflections. It is a product used for decoration, marquetry, making jewels or buttons.
• the mother-of-pearl is formed more precisely by the regular superposition of layers of conchyoline, aragonite crystals as well as traces of water and various ions whose particular disposition causes an interference of the luminous radiations giving it its iridescent aspect.
• the conchyoline is present in very small quantity in mother-of-pearl (about 4 to 6%) and determine its structuring by serving as "cement" with the crystals of aragonite (which represent 90% of the nacre).
• the mother-of-pearl thus consists of stacked small crystals of aragonite 500 nm thick, separated by a very thin layer (approximately 50 nm) of protein which ensures the toughness of the whole.
• the mother-of-pearl layer or coating on the solid to be marked according to the process of the invention is preferably of a thickness of at least 20 ⁇ , or even at least 100 ⁇ , for example at least 500 ⁇ .
• the solid is preferably spherical, with an average diameter preferably of between 1 and 20 mm, in general between 2 and 12 mm.
• a more particularly preferred application of the marking method according to the invention concerns the marking of pearlescent pearls.
• the marking process is suitable for all types of pearls, whether natural pearls or cultured pearls.
• the labeling process is carried out on a pearl of culture, produced by a pearl oyster, for example of the species Pinctada margaritifera, and in particular the oyster Pinctada margaritifera var. Cumingui who lives in French Polynesia and who allows the production of Tahitian pearls.
• the method is simple to implement: it consists in immersing the solid comprising the mother-of-pearl coating in an aqueous solution comprising at least one photoluminescent tracer, for a time sufficient to obtain the attachment of said photoluminescent tracer to the mother-of-pearl coating.
• fixation is meant a fixation of the tracer to the solid stable over time.
• the fixing of the photoluminescent tracer is particularly resistant to different types of washes and / or pearlescent pearl treatments (as described in examples), such as gentle washing with bleach, soap, sweat, water and alcohol.
• the association can also resist the natural friction of the skin or the textile.
• the fixing of the tracer is not resistant to polishing by mechanical abrasion, affecting the surface layer of the pearly pearl.
• One of the advantages of the process according to the invention is that it makes it possible to simultaneously mark a large number of solids, for example a large number of pearlescent pearls.
• a plurality of solids for example at least 100 pearlescent pearls, or several hundred pearlescent pearls are immersed in a bath of a solution containing the photoluminescent tracer (s) used (s). ) for their marking.
• the conditions for bringing the photoluminescent tracer into contact with the mother-of-pearl are such that said tracer is fixed on the surface layer of the pearlescent coating to a thickness not exceeding 20 ⁇ , preferably at most 10 ⁇ .
• said tracer remains on the surface layer of the pearlescent coating.
• the marking When applied to the marking of the beads, the marking then does not resist mechanical abrasion (polishing) of the pearl, which generally eliminates a surface layer of at least 10 ⁇ , and the marking process thus makes it possible to guarantee that the pearls do not not polished.
• the choice of the photoluminescent tracer is free, but guided on the one hand by the adsorption or penetration properties for its attachment to the nacre coating and on the other hand by its photoluminescence properties for its detection.
• photoluminescent tracer any element, small molecule, macromolecule, metal or organometallic complex, or composition, for emitting a photoluminescent signal alone, or in combination with a natural constituent of the nacre.
• the photoluminescent signal emitted by the tracer after attachment to the surface layer of the mother-of-pearl must be detectable with respect to the natural photoluminescent signal possibly emitted by the nacre of the said solid, for example, the pearl.
• detectable it is intended to be able to identify their presence or not in the solid (for example the pearl) beyond a certain concentration and even if possible to quantify their concentration as soon as they are present in the medium.
• the "photoluminescent tracer” has the property of absorbing light energy (excitation light) and of slowly returning it in the form of fluorescent or phosphorescent light (emission light) within a certain time period. preferably greater than 100 ns, and preferably greater than 1 ⁇ 8.
• photoluminescent tracers that may be used, it is possible to choose, for example, those detectable by time-resolved fluorescence in the presence of mother-of-pearl.
• These photoluminescent tracers may be chosen from rare earth semiconductors, oxides, fluorides or vanadates, organic photoluminescent molecules (for example tetracycline or calcein), transition metal ions or rare earth ions. linked or not to complexing molecules and / or molecules to improve their absorption and their mixtures and / or alloys.
• these may be rare earth ions, for example, lanthanides.
• said photoluminescent tracer is a lanthanide selected from Gd, Dy, Lu, Yb, Sm, Ho, Eu, Tb, Nd, Er, or mixtures thereof, for example a combination of gadolinium and europium.
• the marking solution is a lanthanide selected from Gd, Dy, Lu, Yb, Sm, Ho, Eu, Tb, Nd, Er, or mixtures thereof, for example a combination of gadolinium and europium.
• one or more photoluminescent tracers are immersed in a marking solution.
• the labeling solution comprises at least one photoluminescent tracer, or a combination of at least two photoluminescent tracers, with identical or different concentrations.
• the product thus labeled for example, the pearl thus marked, will emit a specific signal, depending on the type of photoluminescent tracer used, its concentration in the aqueous solution, and the immersion time in the aqueous solution.
• This specific signature can be used for example to code certain information related to the pearl, including its quality and / or its geographical origin.
• the pH of the solution is adapted to promote the marking and to avoid degradation of the product to be marked, for example pearlescent pearls.
• a pH of between 5 and 6 will be chosen.
• said labeling solution comprises a combination of distinct lanthanides.
• the metals of the lanthanide series include atomic number elements from 57 (lanthanum) to 71 (lutetium).
• a photoluminescent tracer for the labeling method according to the invention a lanthanide selected from Gd, Dy, Lu, Yb, Sm, Ho, Eu, Tb, Nd, Er will be used. , or mixtures thereof, for example at least Gd and Eu.
• said labeling solution comprises the following photoluminescent tracers: Gd 3+ / Eu 2+ , Gd 3+ / Eu 3+ , Mn 2+ / Eu 3+ , Mn 2+ / Pb 2+ , Sm 2+ / Fe 3+ .
• said labeling solution comprises a combination of lanthanides chosen from: Gd, Dy, Sm, Eu, Tb, Nd, Er, for example a combination of Tb and Eu.
• concentrations of these lanthanides are example between 10 " 5 and 10 " 2 M in said marking solution.
• the lanthanides can be associated with complexing or chelating molecules either naturally present in the nacre or added to the marking solution.
• complexing molecules or "chelating agent” is meant any molecule capable of forming with a metal agent, a complex comprising at least two coordination bonds.
• a complexing agent having a coordination of at least 6, for example at least 8, and a dissociation constant of the complex, pKd, greater than 10 and preferably greater than 15, with a lanthanide, will be chosen. .
• dissociation constant pKd is understood to mean the measurement of the equilibrium between the ions in the complexed state by the ligands and those free dissociated in the solvent. Precisely, it is less the logarithm in the base of the dissociation product (- log (Kd)), defined as the equilibrium constant of the reaction which translates the transition from the complexed state to the ionic state.
• Such complexing agents are preferably polydentate chelating molecules chosen from families of polyamine-type polycarboxylic acid molecules and having a high potential number of coordination sites, preferably greater than 6, such as certain macrocycles.
• DOTA or 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid of the following formula, will be selected:
• each type of photoluminescent tracer is preferably characterized by the emission of one or more specific photoluminescence signals, by example of different transmission and / or excitation wavelengths. Examples of implementation of the marking method are described below, without being limiting. So marked such ⁇
• the invention thus relates to a pearlescent pearl, for example a pearl of culture, comprising at least one tracer or a combination of photoluminescent tracers on the surface layer of the nacrière layer, for example to a thickness of at most 20 ⁇ of said superficial layer, preferably at most 10 ⁇ , said photoluminescent tracer being detectable vis-à-vis the natural photoluminescence said pearl pearl.
• Said pearl according to the invention comprises in particular a photoluminescent tracer which may be chosen from a rare earth ion, preferably a lanthanide, for example gadolinium, europium or their mixtures.
• a photoluminescent tracer which may be chosen from a rare earth ion, preferably a lanthanide, for example gadolinium, europium or their mixtures.
• superficial pearl shell Preferably, it can be easily removed by polishing.
• the bead comprises less than 1 ppm of photoluminescent tracer.
• Procédé..4. [identification of a product.
• the invention also relates to a method for identifying a labeled solid according to the labeling method of the invention or a labeled pearl, characterized in that it comprises the time-resolved fluorescence detection of the photoluminescent tracers.
• the detection method must make it possible to identify the specific photoluminescent signal of the tracer (s) used for the marking.
• the method can detect the presence of a combination of photoluminescent tracers present on the labeled solid and / or pearl, and if appropriate, their absolute or relative amounts.
• the method includes
• the invention is based on the use of photoluminescent tracers capable of emitting (alone or in combination with other elements) a signal after at least 100 ns, preferably at least 1 ⁇ 8 after the end of the excitation pulse.
• the collection of light after at least 100 ns, preferably at least 1 ⁇ 8 after the end of the excitation pulse, thus makes it possible to discriminate between the light naturally emitted by mother-of-pearl and the photoluminescent tracers attached to the superficial layer of mother-of-pearl. .
• the invention therefore also relates to a device comprising the appropriate detection means for implementing the identification method of the labeled solid, or a bead according to the invention.
• This device comprises for example
• a transmitting device making it possible to send pulsed light onto the marked solid, for example the pearl, (preferably in the UV) for example with a frequency lower than 1 kHz,
• a receiver device for detecting the light emitted by the marked solid, for example the pearl, a receptacle or support for positioning the marked solid, for example a bead, said solid being preferably positioned at an angle less than 90 ° between the excitation source, the solid and the detector,
• a wavelength sorting or selection device for identifying the emitted light of interest (for example by filters, by monochromator (Czerny-Turner or other type) or by network),
• Such a device is preferably portable and / or ergonomic, so for example to be used by a non-specialist, for example a customs officer or a jeweler.
• the identification method and the devices according to the invention can advantageously be used to identify, for example, the origin of production and / or the quality of a product marked by the marking process of the invention, for example a pearl. pearly.
• the invention could be implemented to certify the geographical origin and / or the quality of the cultured pearls, for example French Polynesia cultured pearls.
• a specific combination of photoluminescent tracers is used to encode the geographical origin and / or quality of the pearly pearl.
• the invention thus provides both the marking method for tracing and / or the identification of the production origin and / or the quality of the pearly pearl, and also the device for verifying / certifying the origin. and / or the quality of a pearl by identifying the presence of specific tracers.
• Figure 1 shows beads immersed simultaneously in the marking solution for the required time
• Figure 2 shows the rinsing phase of the marked beads
• Figure 3 shows the sample holder for laboratory detection of the individual marking of a pearl
• EXAMPLE 1 Method for labeling cultured pearls with Mn 2+ manganese ions
• a concentrated labeling solution of manganese ions is prepared so as to obtain a concentration of 50 g / l of MgCl 2 .
• the concentrated labeling solution of the simple manganese compound is diluted with distilled water in the necessary proportions, for example to obtain a final concentration of manganese ions of 0.1 g / l.
• the beads of the same batch are immersed simultaneously in the diluted manganese marking solution for a time ranging from 1 to 5 hours (depending on the marking solution and the size of the beads). During this time a gentle agitation is maintained.
• the pH is maintained at the required value, for example about 5.5.
• all the beads are rinsed with distilled water. After drying in dry air, the marking process is completed and the batch of beads is marked.
• a concentrated solution of samarium Sm 2+ ions is prepared so as to obtain a concentration of 100 g / l of SmCl 2 .
• the concentrated labeling solution of the simple samarium compound is diluted with distilled water in the necessary proportions, for example to obtain a final concentration of samarium ions of 0.1 g / l.
• the beads of the same batch are immersed simultaneously in the diluted samarium marking solution for a time ranging from 1 to 5 hours (depending on the marking solution and the size of the beads). During this time a gentle agitation is maintained. The pH is maintained at the required value, for example about 5.5. After the required time, all the beads are rinsed with distilled water. After drying in dry air, the marking process is completed and the batch of beads is marked.
• EXAMPLE 3 Process for labeling cultured pearls by a combination of rare earth ions europium Eu 3+ / samarium Sm 3+
• a mixed concentrated labeling solution of europium Eu 2 + / samarium Sm 2+ ions is prepared so as to obtain a concentration of 50 g / l of SmCl 2 and 50 g / l of EuCl 2 .
• the concentrated labeling solution of the mixed samarium / europium compound is diluted with distilled water in the necessary proportions, for example to obtain a concentration final samarium ion of 0.1 g / 1.
• the pearls of the same batch are immersed simultaneously in the diluted samarium / europium marking solution for a time ranging from 1 to 5 hours (depending on the marking solution and the size of the beads). During this time a gentle agitation maintained. The pH is maintained at the required value. After the required time, all the beads are rinsed with distilled water. After drying in dry air, the marking process is completed and the batch of beads is marked.
• the bead whose marking is to be determined is placed on a suitable sample holder so that the emission generated by incident light beam striking the bead can be received by the detector.
• the emission is analyzed spectrally using a spectrofluorimeter.
• the device is tuned to the required conditions with a repetition rate of 100 Hz.
• the excitation slot is set to 20 nm and the emission slot is set to 10 nm to obtain sufficient spectral resolution.
• the analysis is then started using the software controlling the spectrofluorimeter.
• a dedicated computer interface analyzes the transmitted signal and generates a simple answer that can report whether the pearl has been marked or not and whether the marking corresponds to a range of quality, a source, or other criteria defined beforehand.
• the marking process is resistant to different types of washing, such as gentle washing with bleach, soapy water, sweat, water and alcohol. It is resistant to natural friction on the skin or textile but not polishing (mechanical abrasion). Holding simple over time or following a continuous washing with water for several days, for example 30 days, has shown that no change in the signal was made. Aging with alcohol at 45 ° for 48 hours does not cause any significant modification of the signal. Washing with soapy water (5% detergent) for 48 hours at room temperature does not cause any signal modification as well as washing in a dishwasher-like automated system (cycle 2 hours at 45 ° C).

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Citations (8)

• 2014
  • 2014-01-10 FR FR1450186A patent/FR3016440B1/fr active Active
• 2015
  • 2015-01-09 WO PCT/FR2015/050047 patent/WO2015104509A1/fr active Application Filing

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