Patents by Inventor Hidefumi Fujita
Hidefumi Fujita 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: 20240132368Abstract: A powder contains a niobium complex and lithium, an amount of niobium being 25 mass % or more and 75 mass % or less, a proportion of niobium in metal elements of the powder is 0.775 or more and 0.950 or less in terms of mass ratio. When the powder is dissolved in 8 times its mass of water at 25° C., a niobium content contained in a filtrate thereof is 80 mass % or more of an amount of niobium contained in the powder before dissolution. The powder is obtained by mixing a niobium compound, a lithium compound, an alkali, hydrogen peroxide, and water to obtain an aqueous solution containing a niobium complex and lithium and then drying the solution at a temperature equal to or lower than a decomposition temperature of the niobium complex. The powder is suitable for preparing a lithium niobate precursor solution for coating positive electrode active material particles.Type: ApplicationFiled: March 16, 2022Publication date: April 25, 2024Inventors: Masahiro YOSHIDA, Hidefumi FUJITA, Koji TANOUE
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Publication number: 20230051009Abstract: Provided is a lithium-containing oxide precursor solution for coating an electrode active material that is capable of improving the coverage of a coating layer that is formed by applying the lithium-containing oxide precursor solution to the surface of powder of the electrode active material and king it, and that is easy to handle in a normal atmosphere because a solution composed mainly of water is used as a solvent. The lithium-containing oxide precursor solution for coating an electrode active material includes Li in an amount of 0.1 mass % or more and 5.0 mass % or less, at least one element selected from Nb, F, Fe, P, Ta, V, Ge, B, Al, Ti, Si, W, Zr, Mo, S, Cl, Br, and I in an amount of 0.05 mass % or more and 35 mass % or less, and water in an amount of 60 mass % or more and 98.4 mass % or less. The value of absorbance of the solution at a wavelength of 660 nm is 0.1 or less, and the value of surface energy thereof is 72 mN/m or less.Type: ApplicationFiled: August 1, 2022Publication date: February 16, 2023Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Masahiro YOSHIDA, Hidefumi FUJITA, Koji TANOUE, Kazuki MURAISHI, Masaru KUBOTA, Yuki ISHIGAKI
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Publication number: 20230045543Abstract: Provided are a coated active material having excellent properties that can reduce the reaction resistance of a battery, and a method for producing a coated active material that can achieve both a high processing speed and high processing quality. The method for producing a coated active material includes: mixing an electrode active material and a coating solution containing Li and an element M and having a surface energy of 72 mN/m or less to prepare a slurry; and drying the slurry in an air flow and thereby causing a Li-containing oxide to adhere to at least a portion of the surface of the electrode active material, to obtain a coated active material, where the element M is at least one element selected from Nb, F, Fe, P, Ta, V, Ge, B, Al, Ti, Si, W, Zr, Mo, S, Cl, Br, and I.Type: ApplicationFiled: July 25, 2022Publication date: February 9, 2023Applicants: DOWA ELECTRONICS MATERIALS CO., LTD., TOYOTA JIDOSHA KABUSHIKI KAISHAInventors: Kazuki MURAISHI, Masaru KUBOTA, Yuki ISHIGAKI, Masahiro YOSHIDA, Hidefumi FUJITA, Koji TANOUE
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Publication number: 20220392676Abstract: A silicon oxide-coated soft magnetic powder, in which the ratio of a volume-based cumulative 50% particle diameter D50 (HE) according to a dry laser diffraction particle size distribution analysis to the same particle diameter D50 (MT) according to a wet laser diffraction particle size distribution analysis is 0.7 or more, and a coverage ratio R defined by R=Si×100/(Si+M) (Si and M are molar fractions of Si and elements constituting the soft magnetic powder) is 70% or more is obtained by subjecting a slurry containing a soft magnetic powder containing 20 mass % or more of iron and a hydrolysate of a silicon alkoxide to a dispersion treatment when the surface of the soft magnetic powder is coated with the hydrolysate in a mixed solvent of water and an organic substance. The powder has good insulation/dispersibility properties and a high filling factor during molding.Type: ApplicationFiled: November 19, 2020Publication date: December 8, 2022Inventors: Hidefumi FUJITA, Koji TANOUE, Keisuke YAMADA, Tetsuya KAWAHITO
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Publication number: 20190240735Abstract: [Problem] In the production of silver nanowires, the necessarily amount of the silver-containing liquid is decreased, and the yield of long silver nanowires is improved. [Solution] A method for producing silver nanowires, including adding a silver-containing liquid to an alcohol solvent having dissolved therein a chloride, a bromide, an aluminum salt, an alkali metal hydroxide, and an organic protective agent, so as to perform reduction deposition of silver in a wire form in the alcohol solvent, the silver-containing liquid to be added having dissolved therein a silver compound in a silver concentration of from 3.5 to 32.0 mol/L. The silver-containing liquid used is preferably a water-containing solvent having a mass proportion of water of from 4.0 to 100.0%.Type: ApplicationFiled: October 25, 2017Publication date: August 8, 2019Inventors: Kimitaka SATO, Hidefumi FUJITA
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Patent number: 10350679Abstract: In a fine silver particle dispersing solution wherein 30 to 75% by weight of fine silver particles, which are coated with an organic acid having a carbon number of 5 to 8 or a derivative thereof and which have an average particle diameter of 1 to 100 nm, are dispersed in a water-based dispersion medium which is a solvent containing water as a main component, the fine silver particle dispersing solution containing ammonia and nitric acid, there is added 0.15 to 0.6% by weight of a surface regulating agent, which preferably contains a polyether-modified polydimethylsiloxane and a polyoxyethylene alkyl ether or a polyether, or 0.005 to 0.6% by weight of an antifoaming agent which is preferably a silicone antifoaming agent.Type: GrantFiled: May 12, 2015Date of Patent: July 16, 2019Assignee: Dowa Electronics Materials Co., Ltd.Inventors: Yu Murano, Hidefumi Fujita, Daisuke Itoh, Shuji Yamashita, Daiki Yoshihara
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Publication number: 20180077798Abstract: To provide a copper electroconductive film formed on a paper substrate, the copper electroconductive film being considerably improved in weather resistance and electroconductivity. The problem can be achieved by an electroconductive film formed by pressing a sintered electroconductive film formed by sintering copper particles in a coating film containing copper powder on a paper substrate along with the substrate, the electroconductive film having an area ratio of copper occupying on a cross section of the electroconductive film in parallel to a thickness direction thereof of 82.0% or more. The electroconductive film can be produced by pressing, for example, by roll press to from 90 to 190° C., after light sintering.Type: ApplicationFiled: December 16, 2015Publication date: March 15, 2018Inventors: Hidefumi FUJITA, Shuji KANEDA, Daisuke ITOH
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Publication number: 20170362455Abstract: After there is prepared a conductive paste which contains fine copper particles having an average particle diameter of 1 to 100 nm, each of the fine copper particles being coated with an azole compound, such as benzotriazole, coarse copper particles having an average particle diameter of 0.Type: ApplicationFiled: January 6, 2016Publication date: December 21, 2017Applicant: Dowa Electronics Materials Co., Ltd.Inventors: Hidefumi Fujita, Shuji Kaneda, Yu Murano, Daisuke Itoh
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Patent number: 9732236Abstract: After there is prepared a conductive paste which contains fine copper particles having an average particle diameter of 1 to 100 nm, each of the fine copper particles being coated with an azole compound, coarse copper particles having an average particle diameter of 0.3 to 20 ?m, a glycol solvent, such as ethylene glycol, and at least one of a polyvinylpyrrolidone (PVP) resin and a polyvinyl butyral (PVB) resin and wherein the total amount of the fine copper particles and the coarse copper particles is 50 to 90% by weight, the weight ratio of the fine copper particles to the coarse copper particles being in the range of from 1:9 to 5:5, the conductive paste thus prepared is applied on a substrate by screen printing to be preliminary-fired by vacuum drying, and then, fired with light irradiation by irradiating with light having a wavelength of 200 to 800 nm at a pulse period of 500 to 2000 ?s and a pulse voltage of 1600 to 3800 V to form a conductive film on the substrate.Type: GrantFiled: December 5, 2014Date of Patent: August 15, 2017Assignee: Dowa Electronics Materials Co., Ltd.Inventors: Shuji Kaneda, Hidefumi Fujita, Daisuke Itoh
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Publication number: 20170087633Abstract: In a fine silver particle dispersing solution wherein 30 to 75% by weight of fine silver particles, which are coated with an organic acid having a carbon number of 5 to 8 or a derivative thereof and which have an average particle diameter of 1 to 100 nm, are dispersed in a water-based dispersion medium which is a solvent containing water as a main component, the fine silver particle dispersing solution containing ammonia and nitric acid, there is added 0.15 to 0.6% by weight of a surface regulating agent, which preferably contains a polyether-modified polydimethylsiloxane and a polyoxyethylene alkyl ether or a polyether, or 0.005 to 0.6% by weight of an antifoaming agent which is preferably a silicone antifoaming agent.Type: ApplicationFiled: May 12, 2015Publication date: March 30, 2017Inventors: Yu Murano, Hidefumi Fujita, Daisuke Itoh, Shuji Yamashita, Daiki Yoshihara
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Patent number: 9537202Abstract: A silver particle dispersing solution, which contains 50-70% by weight of silver particles having an average particle diameter of 20 nm or less, is applied on a substrate by the flexographic printing, and then, calcined to produce a booster antenna wherein a silver conductive film, which contains 10-50% by volume of a sintered body of the silver particles and which has a volume resistivity of 3-100 ??·cm, a surface resistivity of 0.5?/? or less and a thickness of 1-6 ?m, is formed on the substrate. Thus, there is provided a booster antenna which has excellent electrical characteristics and flexibility and which can be inexpensively mass-produced.Type: GrantFiled: February 1, 2013Date of Patent: January 3, 2017Assignee: Dowa Electronics Materials Co. Ltd.Inventors: Daisuke Itoh, Hidefumi Fujita, Yu Murano, Shinichi Konno
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Publication number: 20160346838Abstract: A copper particle dispersing solution obtained by dispersing fine copper particles having an average particle diameter of 1 to 100 nm, each of the fine copper particles being coated with an azole compound, such as benzotriazole, and coarse copper particles having an average particle diameter of 0.3 to 20 ?m in a dispersing medium, such as ethylene glycol, so as to cause the total amount of the fine copper particles and coarse copper particles to be 50 to 90% by weight and so as to cause the ratio of the weight of the fine copper particles to the weight of the coarse copper particles to be in the range of from 1:9 to 5:5, is applied on a substrate by screen printing or flexographic printing to be preliminary-fired with vacuum drying, and then, fired with light irradiation by irradiating light having a wavelength of 200 to 800 nm at a pulse period of 100 to 3000 ?m and a pulse voltage of 1600 to 3600 V, to form a conductive film on the substrate.Type: ApplicationFiled: October 31, 2014Publication date: December 1, 2016Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.Inventors: Hidefumi Fujita, Shuji Kaneda, Daisuke Itoh
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Publication number: 20160312043Abstract: After there is prepared a conductive paste which contains fine copper particles having an average particle diameter of 1 to 100 nm, each of the fine copper particles being coated with an azole compound, coarse copper particles having an average particle diameter of 0.3 to 20 ?m, a glycol solvent, such as ethylene glycol, and at least one of a polyvinylpyrrolidone (PVP) resin and a polyvinyl butyral (PVB) resin and wherein the total amount of the fine copper particles and the coarse copper particles is 50 to 90% by weight, the weight ratio of the fine copper particles to the coarse copper particles being in the range of from 1:9 to 5:5, the conductive paste thus prepared is applied on a substrate by screen printing to be preliminary-fired by vacuum drying, and then, fired with light irradiation by irradiating with light having a wavelength of 200 to 800 nm at a pulse period of 500 to 2000 ?s and a pulse voltage of 1600 to 3800 V to form a conductive film on the substrate.Type: ApplicationFiled: December 5, 2014Publication date: October 27, 2016Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.Inventors: Shuji Kaneda, Hidefumi Fujita, Daisuke Itoh
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Patent number: 9248504Abstract: There are provided a copper powder for conductive paste, which comprises monodisperse and spherical fine copper particles having a sharp particle size distribution and containing no coarse particles and which can form a thinner electrode film while avoiding a bad influence on electric characteristics thereof, and a method for stably producing such a copper powder for conductive paste. After copper is complexed by adding a complexing agent to an aqueous solution containing copper while blowing air into the solution, the blowing of air is stopped, and then, a reducing agent is added to the solution to deposit copper particles by reduction.Type: GrantFiled: September 12, 2011Date of Patent: February 2, 2016Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.Inventors: Yuki Kaneshiro, Shinichi Suenaga, Hidefumi Fujita, Minoru Kishida
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Publication number: 20150364814Abstract: There is provided a silver conductive film capable of inexpensively mass-producing conductive circuits, such as antennas for IC tags, which have excellent electrical characteristic and flexibility, by applying a silver particle dispersing solution, which contains 50-70% by weight of silver particles having a mean particle diameter of 20 nm or less, on a substrate by the flexographic printing, and then, calcining the silver particle dispersing solution to produce a silver conductive film, which contains 10-50% by volume of a sintered body of the silver particles and which has a volume resistivity of 3-100 ??·cm, a surface resistivity of 0.5?/? or less and a thickness of 1-6 ?m.Type: ApplicationFiled: February 1, 2013Publication date: December 17, 2015Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.Inventors: Hidefumi Fujita, Shinichi Konno, Kimitaka Sato, Toshihiko Ueyama
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Publication number: 20150102964Abstract: A silver particle dispersing solution, which contains 50-70% by weight of silver particles having an average particle diameter of 20 nm or less, is applied on a substrate by the flexographic printing, and then, calcined to produce a booster antenna wherein a silver conductive film, which contains 10-50% by volume of a sintered body of the silver particles and which has a volume resistivity of 3-100 ??·cm, a surface resistivity of 0.5?/? or less and a thickness of 1-6 ?m, is formed on the substrate. Thus, there is provided a booster antenna which has excellent electrical characteristics and flexibility and which can be inexpensively mass-produced.Type: ApplicationFiled: February 1, 2013Publication date: April 16, 2015Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.Inventors: Daisuke Itoh, Hidefumi Fujita, Yu Murano, Shinichi Konno
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Patent number: 8968824Abstract: A silver conductive film is formed on a substrate in a continuous roll-to-roll system by applying a fine silver particle dispersing solution, which contains 30 to 70 wt % of fine silver particles dispersed in a water based dispersing medium, to a halide, such as a chlorine compound, which is applied to the substrate, by flexographic printing, and thereafter, heating the substrate at 60 to 200° C. for 0.1 to 5 seconds in an infrared (IR) heating open, which is installed on the printing path, to carry out calcination.Type: GrantFiled: March 14, 2013Date of Patent: March 3, 2015Assignee: Dowa Electronics Materials Co., Ltd.Inventors: Michael A. Mastropietro, Kimitaka Sato, Hidefumi Fujita
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Publication number: 20140272118Abstract: A silver conductive film is formed on a substrate in a continuous roll-to-roll system by applying a fine silver particle dispersing solution, which contains 30 to 70 wt % of fine silver particles dispersed in a water based dispersing medium, to the substrate via a halide, such as a chlorine compound, which is applied to the substrate, by flexographic printing, and thereafter, heating the substrate at 60 to 200° C. for 0.1 to 5 seconds in an infrared (IR) heating open, which is installed on the printing path, to carry out calcination.Type: ApplicationFiled: March 14, 2013Publication date: September 18, 2014Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.Inventors: Michael A. Mastropietro, Kimitaka Sato, Hidefumi Fujita
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Publication number: 20140120359Abstract: [OBJECT] A composition of a metal nanoparticle is provided in which reproducibility in a method of producing a metal film with excellent low-temperature sinterable properties is improved. An article using the metal nanoparticle composition is also provided. [SOLVING MEANS] A composition of a metal nanoparticle that has a secondary aggregation diameter (median diameter) of 2.0 ?m or less as determined by disk centrifugal-type particle size measurement is used.Type: ApplicationFiled: March 17, 2011Publication date: May 1, 2014Applicant: DOWA Electronics Materials Co., Ltd.Inventors: Gregory A JABLONSKI, Michael A MASTROPIETRO, Kimitaka SATO, Satoru KURITA, Hidefumi FUJITA
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Patent number: 8673049Abstract: A silver nanoparticle composition is provided which is possible to be sintered through sintering at a low temperature in a short time and to form silver electro conductive film and wiring which is favorable for adhesion to a substrate and low in resistance, and articles using the same are provided. The silver nanoparticle composition is provided, wherein a main component of a solvent is water, a pH of the composition is within a range of 5.3 to 8.0, a silver nanoparticle included in the composition is protected by an organic acid or a derivative thereof, and the content of the organic acid or the derivative thereof with respect to silver is 2 to 20% by mass.Type: GrantFiled: August 27, 2010Date of Patent: March 18, 2014Assignees: DOWA Electronics Materials Co., Ltd., PChem Associates, Inc.Inventors: Gregory A. Jablonski, Michael A. Mastropietro, Kimitaka Sato, Hiromasa Miyoshi, Hidefumi Fujita