Patents by Inventor Jean-Francois Letard
Jean-Francois Letard has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Publication number: 20240124719Abstract: A method for producing a photoluminescent composition and the composition obtained, in particular form granular photoluminescent compounds, chosen in particular, and not exclusively, from the following families, based on an inorganic matrix and a doping ion, the photoluminescent composition being intended to be introduced with at least one filler into a transparent matrix. The method comprises a preparation step of: —choosing a first photoluminescent compound PH1 with a particle size range comprising a peak centered on a value P1 corresponding to a particle diameter D1, —choosing at least one second photoluminescent compound PH2 with a particle size range comprising a peak centered on a value P2 corresponding to a particle diameter D2, —choosing the diameter D2 equal to the maximum measurement M1 of the volumetric space V1 freed by the presence of at least four juxtaposed particles of diameter D1.Type: ApplicationFiled: December 13, 2019Publication date: April 18, 2024Inventor: Jean-François LETARD
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Patent number: 9594264Abstract: An electrical device in provided having two electrodes separated from one another, wherein one temperature controlled electronic spin-state transition particle is in direct contact with each of the two electrodes, the particle being of the ionic type and containing a transition metal bearing a cationic charge.Type: GrantFiled: February 7, 2012Date of Patent: March 14, 2017Assignee: Centre National de la Recherche Scientifique—CNRS-Inventors: Jean-François Letard, Céline Etrillard, Bernard Doudin, Vina Faramarzi, Jean-François Dayen
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Patent number: 9193203Abstract: The invention relates to a treatment for printing a surface with an ink that includes a compound that exhibits a change of electronic spin state as a function of temperature, imparting optical properties such that the ink is visible in a temperature range that includes an ambient temperature of around 20° C. and is transparent in the visible spectrum when the ink is brought to a temperature above said range and then brought back down to a temperature within the range.Type: GrantFiled: July 21, 2011Date of Patent: November 24, 2015Assignee: Centre National de la Recherche Scientifique—CNRSInventor: Jean-Francois Letard
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Patent number: 8963106Abstract: A method is provided for the thermal photoswitching of spin-transition compounds from the low-spin state to the high-spin state, including at least one step of exposing the material to a non-polarized laser beam which is at room temperature, and the wavelength of which is in the infrared range and the power of which is 1 mW·cm?2 to 1 W·cm?2. The method may be used for the temporary or permanent marking of materials including particles of at least one spin-transition compound including an iron(II) and triazole ligand compound.Type: GrantFiled: July 20, 2011Date of Patent: February 24, 2015Assignee: Centre National de la Recherche ScientifiqueInventors: Jean-Francois Letard, Eric Freysz
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Patent number: 8753743Abstract: The invention relates to a material composed of nanoparticles essentially comprising a spin transition compound. The compound corresponds to the formula [ ( Fe 1 - y ? M y ? L 3 ) w ? L 3 ] [ X 2 x ? ( 1 - z x ? ) ? Y 2 ? ? z x ? ] w in which L represents a 1,2,4-triazole ligand carrying an R substituent on the nitrogen in the 4 position; X is an anion having the valency x, 1?x?2; Y is an anion other than X having the valency x?, 1?x??2; R is an alkyl group or an R1R2N— group in which R1 and R2 represent, each independently of the other, H or an alkyl radical; M is a metal having a 3d4, 3d5, 3d6 or 3d7 configuration, other than Fe; 0?y?1; 0?z?2; 3?w?1500. Applications: thermochromic pigment, data storage, optical limiters, contrast agent.Type: GrantFiled: September 14, 2012Date of Patent: June 17, 2014Assignee: Centre National de la Recherche ScientifiqueInventors: Jean-Francois Letard, Olivier Nguyen, Nathalie Daro
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Patent number: 8709599Abstract: A material is composed of at least one spin transition compound that corresponds to the formula Fe1-mMm(R-Trz)3XbYc (I) in which M is a metal having a 3d4, 3d5, 3d6 or 3d7 configuration, other than Fe; 0?m?1; R-Trz represents a 1,2,4-triazole ligand carrying an R substituent on the nitrogen in the 4 position; R is an alkyl group or an R1R2N— group in which R1 and R2 represent, each independently of the other, H or an alkyl radical; X represents at least one noncoloring monovalent or divalent anion; Y represents at least one anion which has a coloring group; and b and c are chosen so that the electrical neutrality of the compound (I) is adhered to. A process for the preparation of this material and to its use as thermochromic pigment, as support for data storage or as optical limiter.Type: GrantFiled: June 11, 2008Date of Patent: April 29, 2014Assignee: Centre National de la Recherche ScientifiqueInventors: Jean-François Letard, Nathalie Daro, Sandie Auffret
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Publication number: 20130306936Abstract: An electrical device in provided having two electrodes separated from one another, wherein one temperature controlled electronic spin-state transition particle is in direct contact with each of the two electrodes, the particle being of the ionic type and containing a transition metal bearing a cationic charge.Type: ApplicationFiled: February 7, 2012Publication date: November 21, 2013Applicant: Centre National De La Recherche Scientifique - CNRS -Inventors: Jean-Francois Letard, Celine Etrillard, Bernard Doudin, Vina Faramarzi, Jean-Francois Dayen
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Publication number: 20130214179Abstract: A method is provided for the thermal photoswitching of spin-transition compounds from the low-spin state to the high-spin state, including at least one step of exposing the material to a non-polarised laser beam which is at room temperature, and the wavelength of which is in the infrared range and the power of which is 1 mW.cm?2 to 1 W.cm?2. The method may be used for the temporary or permanent marking of materials including particles of at least one spin-transition compound including an iron(II) and triazole ligand compound.Type: ApplicationFiled: July 20, 2011Publication date: August 22, 2013Applicant: CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUEInventors: Jean-Francois Letard, Eric Freysz
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Publication number: 20130127947Abstract: The invention relates to a treatment for printing a surface with an ink that comprises a compound that exhibits a change of electronic spin state as a function of temperature, imparting optical properties such that the ink is visible in a temperature range that includes an ambient temperature of around 20° C. and is transparent in the visible spectrum when the ink is brought to a temperature above said range and then brought back down to a temperature within the range.Type: ApplicationFiled: July 21, 2011Publication date: May 23, 2013Applicant: CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUE-CNRSInventor: Jean-Francois Letard
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Publication number: 20130011680Abstract: The invention relates to a material composed of nanoparticles essentially comprising a spin transition compound. The compound corresponds to the formula [ ( Fe 1 - y ? M y ? L 3 ) w ? L 3 ] [ X 2 x ? ( 1 - z x ? ) ? Y 2 ? ? z x ? ] w in which L represents a 1,2,4-triazole ligand carrying an R substituent on the nitrogen in the 4 position; X is an anion having the valency x, 1?x?2; Y is an anion other than X having the valency x?, 1?x??2; R is an alkyl group or an R1R2N— group in which R1 and R2 represent, each independently of the other, H or an alkyl radical; M is a metal having a 3d4, 3d5, 3d6 or 3d7 configuration, other than Fe; 0?y?1; 0?z?2; 3?w?1500. Applications: thermochromic pigment, data storage, optical limiters, contrast agent.Type: ApplicationFiled: September 14, 2012Publication date: January 10, 2013Applicant: Centre National De La Recherche ScientifiqueInventors: Jean-François LETARD, Olivier NGUYEN, Nathalie DARO
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Publication number: 20100178511Abstract: The invention relates to a material composed of at least one spin transition compound. The compound corresponds to the formula Fe1-mMm(R-Trz)3XbYc (I) in which M is a metal having a 3d4, 3d5, 3d6 or 3d7 configuration, other than Fe; 0?m?1; R-Trz represents a 1,2,4-triazole ligand carrying an R substituent on the nitrogen in the 4 position; R is an alkyl group or an R1R2N-group in which R1 and R2 represent, each independently of the other, H or an alkyl radical; X represents at least one noncoloring monovalent or divalent anion; Y represents at least one anion which has a coloring group; and b and c are chosen so that the electrical neutrality of the compound (I) is adhered to. The invention also relates to the process for the preparation of the material and to its use as thermo-chromic pigment, as support for data storage or as optical limiter.Type: ApplicationFiled: June 11, 2008Publication date: July 15, 2010Applicant: CENTRE NATIONAL DE LA RECHERCHE SCIENTIFIQUEInventors: Jean-Francois Letard, Nathalie Daro, Sandie Auffret
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Patent number: 7638831Abstract: A molecular memory including a substrate made of silicon; a set of condensers, each condenser including two conductive layers constituting armatures of the condensers and between which is placed a dielectric layer; and a connector to provide electric contacts with external circuits, wherein the dielectric layer comprises at least partially a polymer containing triazole derivatives, a spin transition phenomenon support material or a spin transition molecular complex; and a method for manufacturing a molecular memory including covering a substrate with a conductive layer; coating a dielectric material on the conductive layer; covering the dielectric material with the conductive layer; impregnating by immersion a buffer in an inking solution of hexadecanethiol; drying and washing the impregnated buffer; creating a protective monolayer on the conductive layer by application of the impregnated, dried and washed buffer; and creating a chemical etching on the sample.Type: GrantFiled: August 29, 2002Date of Patent: December 29, 2009Assignee: Centre National de la Recherche Scientifique - CNRSInventors: Azzedine Bousseksou, Christophe Vieu, Jean-Francois Letard, Philippe Demont, Jean-Pierre Tuchagues, Laurent Malaquin, Jerôme Menegotto, Lionel Salmon
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Publication number: 20080311401Abstract: The invention relates to a material composed of nanoparticles essentially comprising a spin transition compound. The compound corresponds to the formula [(Fe1-yMyL3)wL3][X2/x(1-z/x?)Y2z/x?]w in which L represents a 1,2,4-triazole ligand carrying an R substituent on the nitrogen in the 4 position; X is an anion having the valency x, 1?x?2; Y is an anion other than X having the valency x?, 1?x??2; R is an alkyl group or an R1R2N— group in which R1 and R2 represent, each independently of the other, H or an alkyl radical; M is a metal having a 3d4, 3d5, 3d6 or 3d7 configuration, other than Fe; 0?y?1; 0?z?2; 3?w?1500. Applications: thermochromic pigment, data storage, optical limiters, contrast agent.Type: ApplicationFiled: December 5, 2006Publication date: December 18, 2008Inventors: Jean-Francois Letard, Olivier Nguyen, Nathalie Daro
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Publication number: 20050161728Abstract: A molecular memory including a substrate made of silicon; a set of condensers, each condenser including two conductive layers constituting armatures of the condensers and between which is placed a dielectric layer; and a connector to provide electric contacts with external circuits, wherein the dielectric layer comprises at least partially a polymer containing triazole derivatives, a spin transition phenomenon support material or a spin transition molecular complex; and a method for manufacturing a molecular memory including covering a substrate with a conductive layer; coating a dielectric material on the conductive layer; covering the dielectric material with the conductive layer; impregnating by immersion a buffer in an inking solution of hexadecanethiol; drying and washing the impregnated buffer; creating a protective monolayer on the conductive layer by application of the impregnated, dried and washed buffer; and creating a chemical etching on the sample.Type: ApplicationFiled: August 29, 2002Publication date: July 28, 2005Applicant: Centre National de la Recherche Scientifique-CNRSInventors: Azzedine Bousseksou, Christophe Vieu, Jean-Francois Letard, Philippe Demont, Jean-Pierre Tuchagues, Laurent Malaquin, Jerome Menegotto, Lionel Salmon