Patents by Inventor Tomokazu Ishikura
Tomokazu Ishikura 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: 20230280296Abstract: A sensor including a micro-bridge structure, wherein the micro-bridge structure comprises a concave geometry, a first electrode on a surface of the micro-bridge structure, a second electrode on the surface of the micro-bridge structure, and a chemical sensing material coupled to the micro-bridge structure overlying the first electrode and the second electrode and exposed to an environment. The chemical sensing material overlays the first electrode and the second electrode and is within the concave geometry of the micro-bridge structure such that the chemical sensing material settles into the concave geometry of the micro-bridge structure during fabrication of the sensor, and wherein the chemical sensing material has an electrical resistance responsive to a concentration of gas in the environment.Type: ApplicationFiled: February 28, 2023Publication date: September 7, 2023Applicant: TDK CORPORATIONInventors: Nishit GOEL, Stephen BART, Raitaro MASAOKA, Kazutaka FUJITA, Tomokazu ISHIKURA
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Patent number: 11626222Abstract: A ferrite sintered magnet 100 comprises M-type ferrite crystal grains 4 and multiple-crystal grain boundaries 6b surrounded by three or more of the M-type ferrite crystal grains 4. The ferrite sintered magnet 100 contains at least Fe, Ca, B, and Si, and contains 0.005 to 0.9 mass % of B in terms of B2O3. The multiple-crystal grain boundaries 6b contain Si and Ca, and in a case where the molar ratio of Ca to Si in the multiple-crystal grain boundaries 6b is represented by (Ca/Si)G, the following formula is satisfied. 0.1<(Ca/Si)G<0.Type: GrantFiled: October 14, 2020Date of Patent: April 11, 2023Assignee: TDK CorporationInventors: Yoshitaka Murakawa, Hiroyuki Morita, Masanori Ikeda, Shogo Muroya, Tomokazu Ishikura
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Patent number: 11600412Abstract: A ferrite sintered magnet 100 comprises M-type ferrite crystal grains 4 and multiple-crystal grain boundaries 6b surrounded by three or more of the M-type ferrite crystal grains 4. The ferrite sintered magnet 100 contains at least Fe, Ca, B, and Si, and contains 0.005 to 0.9 mass % of B in terms of B2O3. The multiple-crystal grain boundaries 6b contain Si and Ca, and in a case where the molar ratio of Ca to Si in the multiple-crystal grain boundaries 6b is represented by (Ca/Si)G, the following formula is satisfied. 0.1<(Ca/Si)G<0.Type: GrantFiled: October 14, 2020Date of Patent: March 7, 2023Assignee: TDK CorporationInventors: Yoshitaka Murakawa, Hiroyuki Morita, Masanori Ikeda, Shogo Muroya, Tomokazu Ishikura
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Patent number: 11488752Abstract: The present invention provides a ferrite sintered magnet comprising ferrite crystal grains having a hexagonal structure, wherein the ferrite sintered magnet comprises metallic elements at an atomic ratio represented by formula (1). In formula (1), R is at least one element selected from the group consisting of Bi and rare-earth elements, and R comprises at least La. In formula (1), w, x, z and m satisfy formulae (2) to (5). The above-mentioned ferrite sintered magnet further has a coefficient of variation of a size of the crystal grains in a section parallel to a c axis of less than 45%. Ca1-w-xRwSrxFezCom??(1) 0.360?w?0.420??(2) 0.110?x?0.173??(3) 8.51?z?9.71??(4) 0.208?m?0.Type: GrantFiled: September 21, 2020Date of Patent: November 1, 2022Assignee: TDK CorporationInventors: Tomokazu Ishikura, Masanori Ikeda, Yoshitaka Murakawa, Hiroyuki Morita, Shogo Muroya
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Publication number: 20220324721Abstract: A sensing material for detecting hydrogen sulfide capable of detecting hydrogen sulfide even having a low concentration, a hydrogen sulfide-sensitive layer containing the sensing material for detecting hydrogen sulfide, and a metal oxide semiconductor-type gas sensor having the hydrogen sulfide-sensitive layer are provided. The sensing material for detecting hydrogen sulfide includes CuFe2O4-type complex oxide (W). The CuFe2O4-type complex oxide (W) contains, as a main component (W1), 35.0 to 49.5 mol % of iron oxide in terms of Fe2O3 and 50.5 to 65 mol % of copper oxide in terms of CuO, and an average particle diameter of particles is 3 ?m or less.Type: ApplicationFiled: February 23, 2022Publication date: October 13, 2022Applicant: TDK CORPORATIONInventors: Tomokazu ISHIKURA, Raitaro MASAOKA
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Publication number: 20210118598Abstract: A ferrite sintered magnet 100 comprises M-type ferrite crystal grains 4 and multiple-crystal grain boundaries 6b surrounded by three or more of the M-type ferrite crystal grains 4. The ferrite sintered magnet 100 contains at least Fe, Ca, B, and Si, and contains 0.005 to 0.9 mass % of B in terms of B2O3. The multiple-crystal grain boundaries 6b contain Si and Ca, and in a case where the molar ratio of Ca to Si in the multiple-crystal grain boundaries 6b is represented by (Ca/Si)G, the following formula is satisfied. 0.1<(Ca/Si)G<0.Type: ApplicationFiled: October 14, 2020Publication date: April 22, 2021Applicant: TDK CorporationInventors: Yoshitaka MURAKAWA, Hiroyuki MORITA, Masanori IKEDA, Shogo MUROYA, Tomokazu ISHIKURA
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Publication number: 20210090768Abstract: The present invention provides a ferrite sintered magnet comprising ferrite crystal grains having a hexagonal structure, wherein the ferrite sintered magnet comprises metallic elements at an atomic ratio represented by formula (1). In formula (1), R is at least one element selected from the group consisting of Bi and rare-earth elements, and R comprises at least La. In formula (1), w, x, z and m satisfy formulae (2) to (5). The above-mentioned ferrite sintered magnet further has a coefficient of variation of a size of the crystal grains in a section parallel to a c axis of less than 45%. Ca1-w-xRwSrxFezCom??(1) 0.360?w=0.420??(2) 0.110?x?0.173??(3) 8.51?z?9.71??(4) 0.208?m?0.Type: ApplicationFiled: September 21, 2020Publication date: March 25, 2021Applicant: TDK CorporationInventors: Tomokazu ISHIKURA, Masanori IKEDA, Yoshitaka MURAKAWA, Hiroyuki MORITA, Shogo MUROYA
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Patent number: 9793608Abstract: An object is to provide a ferrite composition suitable for an antenna element with a long communication distance in a high-frequency band (for example, 13.56 MHz), a ferrite plate formed of the ferrite composition, a magnetic member for an antenna element formed of the ferrite plate, and an antenna element provided with a member for an antenna element. A ferrite composition, wherein: main components contain, with Fe2O3 conversion, 45.0-49.5 mol % of iron oxide, with CuO conversion, 4.0-16.0 mol % of copper oxide, with ZnO conversion, 19.0-25.0 mol % of zinc oxide, a remaining portion is constituted by nickel oxide, an inevitable impurity is removed with respect to the main components, and as accessory components, with TiO2 conversion, 0.5-2 weight % of titanium oxide, with CoO conversion, 0.35-2 weight % of cobalt oxide are contained.Type: GrantFiled: November 26, 2014Date of Patent: October 17, 2017Assignee: TDK CORPORATIONInventors: Tomokazu Ishikura, Shin Takane, Norizumi Asano, Kosuke Kunitsuka
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Patent number: 9424968Abstract: A magnetic material for antennas including: an M-type hexagonal ferrite represented by the following general formula (1) as a main phase, MA.Fe12-x.MBx.O19 (wherein MA is at least one kind selected from the group consisting of Sr and Ba, MB is MC or MD, MC is at least one kind selected from the group consisting of Al, Cr, Sc and In, MD is an equivalent mixture of at least one kind selected from the group consisting of Ti, Sn and Zr and at least one kind selected from the group consisting of Ni, Zn, Mn, Mg, Cu and Co, X is a number from 1 to 5), and an average crystal particle diameter is equal to or greater than 5 ?m.Type: GrantFiled: January 17, 2012Date of Patent: August 23, 2016Assignee: TDK CORPORATIONInventors: Tomokazu Ishikura, Michihiro Muramoto, Akihiro Harada, Katsumi Kawasaki, Tomofumi Kuroda
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Publication number: 20150180128Abstract: An object is to provide a ferrite composition suitable for an antenna element with a long communication distance in a high-frequency band (for example, 13.56 MHz), a ferrite plate formed of the ferrite composition, a magnetic member for an antenna element formed of the ferrite plate, and an antenna element provided with a member for an antenna element. A ferrite composition, wherein: main components contain, with Fe2O3 conversion, 45.0-49.5 mol % of iron oxide, with CuO conversion, 4.0-16.0 mol % of copper oxide, with ZnO conversion, 19.0-25.0 mol % of zinc oxide, a remaining portion is constituted by nickel oxide, an inevitable impurity is removed with respect to the main components, and as accessory components, with TiO2 conversion, 0.5-2 weight % of titanium oxide, with CuO conversion, 0.35-2 weight % of cobalt oxide are contained.Type: ApplicationFiled: November 26, 2014Publication date: June 25, 2015Inventors: Tomokazu ISHIKURA, Shin TAKANE, Norizumi ASANO, Kosuke KUNITSUKA
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Publication number: 20120229354Abstract: A magnetic material for antennas including: an M-type hexagonal ferrite represented by the following general formula (1) as a main phase, MA.Fe12-x.MBx.O19 (wherein MA is at least one kind selected from the group consisting of Sr and Ba, MB is MC or MD, MC is at least one kind selected from the group consisting of Al, Cr, Sc and In, MD is an equivalent mixture of at least one kind selected from the group consisting of Ti, Sn and Zr and at least one kind selected from the group consisting of Ni, Zn, Mn, Mg, Cu and Co, X is a number from 1 to 5), and an average crystal particle diameter is equal to or greater than 5 ?m.Type: ApplicationFiled: January 17, 2012Publication date: September 13, 2012Applicant: TDK CORPORATIONInventors: Tomokazu ISHIKURA, Michihiro MURAMOTO, Akihiro HARADA, Katsumi KAWASAKI, Tomofumi KURODA
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Patent number: 8252124Abstract: The present invention provides a powder magnetic core low in the loss and high in the saturation magnetic flux density and a method for manufacturing the same. More specifically, the present invention provides a powder magnetic core that comprises a soft magnetic metal powder having an average particle size (D50) of 0.5 to 5 ?m, a half width of diffraction peak in a <110> direction of ?-Fe as measured by X-ray powder diffraction of 0.2 to 5.0°, and an Fe content of 97.0% by mass or more, the core having an oxygen content of 2.0% by mass or more.Type: GrantFiled: March 11, 2011Date of Patent: August 28, 2012Assignee: TDK CorporationInventors: Masahito Koeda, Tomofumi Kuroda, Tomokazu Ishikura, Akihiro Harada, Hiroyuki Ono, Osamu Kido, Satoko Ueda
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Patent number: 8158018Abstract: The ferrite sintered body of the present invention contains main components consisting of 52 to 54 mol % Fe2O3, 35 to 42 mol % MnO and 6 to 11 mol % ZnO as oxide equivalents and additives including Co, Ti, Si and Ca in specified amounts, and has a temperature at which the power loss is a minimal value (bottom temperature) of higher than 120° C. in a magnetic field with an excitation magnetic flux density of 200 mT and a frequency of 100 kHz, and a power loss of 350 kW/m3 or less at the bottom temperature.Type: GrantFiled: March 23, 2009Date of Patent: April 17, 2012Assignee: TDK CorporationInventors: Isao Nakahata, Tomokazu Ishikura, Takuya Aoki
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Publication number: 20110227679Abstract: The present invention provides a powder magnetic core low in the loss and high in the saturation magnetic flux density and a method for manufacturing the same. More specifically, the present invention provides a powder magnetic core that comprises a soft magnetic metal powder having an average particle size (D50) of 0.5 to 5 ?m, a half width of diffraction peak in a <110> direction of ?-Fe as measured by X-ray powder diffraction of 0.2 to 5.0°, and an Fe content of 97.0% by mass or more, the core having an oxygen content of 2.0% by mass or more.Type: ApplicationFiled: March 11, 2011Publication date: September 22, 2011Applicant: TDK CORPORATIONInventors: Masahito KOEDA, Tomofumi KURODA, Tomokazu ISHIKURA, Akihiro HARADA, Hiroyuki ONO, Osamu KIDO, Satoko UEDA
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Publication number: 20090242827Abstract: The ferrite sintered body of the present invention contains main components consisting of 52 to 54 mol % Fe2O3, 35 to 42 mol % MnO and 6 to 11 mol % ZnO as oxide equivalents and additives including Co, Ti, Si and Ca in specified amounts, and has a temperature at which the power loss is a minimal value (bottom temperature) of higher than 120° C. in a magnetic field with an excitation magnetic flux density of 200 mT and a frequency of 100 kHz, and a power loss of 350 kW/m3 or less at the bottom temperature.Type: ApplicationFiled: March 23, 2009Publication date: October 1, 2009Applicant: TDK CorporationInventors: Isao NAKAHATA, Tomokazu Ishikura, Takuya Aoki
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Patent number: 7540972Abstract: For the purpose of providing a Mn—Zn based ferrite material that is small in magnetic field degradation in high frequency bands of 1 MHz or more, the Mn—Zn based ferrite material includes: as main constituents, Fe2O3: 53 to 56 mol %, ZnO: 7 mol % or less (inclusive of 0 mol %), and the balance: MnO; and as additives, Co: 0.15 to 0.65% by weight in terms of Co3O4, Si: 0.01 to 0.045% by weight in terms of SiO2 and Ca: 0.05 to 0.40% by weight in terms of CaCO3; wherein the ? value (the cation defect amount) defined in the present specification satisfies the relation 3×10?3???7×10?3; and the mean grain size is larger than 8 ?m and 15 ?m or less.Type: GrantFiled: January 23, 2007Date of Patent: June 2, 2009Assignee: TDK CorporationInventors: Tomokazu Ishikura, Shinichi Sakano, Masahiko Watanabe
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Publication number: 20070228319Abstract: For the purpose of providing a Mn—Zn based ferrite material that is small in magnetic field degradation in high frequency bands of 1 MHz or more, the Mn—Zn based ferrite material includes: as main constituents, Fe2O3: 53 to 56 mol %, ZnO: 7 mol % or less (inclusive of 0 mol %), and the balance: MnO; and as additives, Co: 0.15 to 0.65% by weight in terms of Co3O4, Si: 0.01 to 0.045% by weight in terms of SiO2 and Ca: 0.05 to 0.40% by weight in terms of CaCO3; wherein the ? value (the cation defect amount) defined in the present specification satisfies the relation 3×10?3???7×10?3; and the mean grain size is larger than 8 ?m and 15 ?m or less.Type: ApplicationFiled: January 23, 2007Publication date: October 4, 2007Applicant: TDK CORPORATIONInventors: Tomokazu Ishikura, Shinichi Sakano, Masahiko Watanabe
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Publication number: 20070205390Abstract: For the purpose of providing a Mn—Zn based ferrite material that is small in loss in high frequency bands of 1 MHz or more and in the vicinity of 100° C., the Mn—Zn based ferrite material includes: as main constituents, Fe2O3: 53 to 56 mol %, ZnO: 7 mol % or less (inclusive of 0 mol %), and the balance: MnO; and as additives, Co: 0.15 to 0.65% by weight in terms of CoO, Si: 0.01 to 0.045% by weight in terms of SiO2 and Ca: 0.05 to 0.40% by weight in terms of CaCO3; wherein the 6 value (the cation defect amount) defined in the present specification defined in the present specification.Type: ApplicationFiled: February 6, 2007Publication date: September 6, 2007Applicant: TDK CORPORATIONInventors: Tomokazu Ishikura, Shinichi Sakano, Isao Nakahata, Masahiko Watanabe