Patents by Inventor Atsuhito Matsukawa

Atsuhito Matsukawa 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).

  • Patent number: 10593453
    Abstract: A magnetic sheet comprises, by vol. %, Fe—Si—Al alloy flat powder: 36% or more. The Fe—Si—Al alloy flat powder comprises, by wt %, 9.3%?Si?9.7%, 5.7%?Al?6.1%, and remaining Fe. The Fe—Si—Al alloy flat powder has: an aspect ratio in a range of 20 or more and 50 or less; a 50% particle size D50 in a range of 50 ?m or more and 100 ?m or less; and a coercivity Hc of 60 A/m or less. The magnetic sheet has a temperature characteristic of permeability ?? measured at 1 MHz exhibiting a maximum value in a range of 0° C. or more and 40° C. or less.
    Type: Grant
    Filed: July 24, 2017
    Date of Patent: March 17, 2020
    Assignee: TDK CORPORATION
    Inventors: Atsuhito Matsukawa, Yoshihiro Honjo, Mitsuhiro Matsuhashi
  • Publication number: 20180025821
    Abstract: A magnetic sheet comprises, by vol. %, Fe—Si—Al alloy flat powder: 36% or more. The Fe—Si—Al alloy flat powder comprises, by wt %, 9.3%?Si?9.7%, 5.7%?Al?6.1%, and remaining Fe. The Fe—Si—Al alloy flat powder has: an aspect ratio in a range of 20 or more and 50 or less; a 50% particle size D50 in a range of 50 ?m or more and 100 ?m or less; and a coercivity Hc of 60 A/m or less. The magnetic sheet has a temperature characteristic of permeability ?? measured at 1 MHz exhibiting a maximum value in a range of 0° C. or more and 40° C. or less.
    Type: Application
    Filed: July 24, 2017
    Publication date: January 25, 2018
    Applicant: TDK CORPORATION
    Inventors: Atsuhito MATSUKAWA, Yoshihiro HONJO, Mitsuhiro MATSUHASHI
  • Patent number: 8038808
    Abstract: A flat soft magnetic material to be used for a noise-suppressing magnetic sheet, wherein the 50% particle size D50 (?m), coercive force Hc (A/m) and bulk density BD (Mg/m3) of the flat soft magnetic material satisfy the following formula (1). D50/(HC×BD)?1.
    Type: Grant
    Filed: April 20, 2009
    Date of Patent: October 18, 2011
    Assignee: TDK Corporation
    Inventors: Atsuhito Matsukawa, Katsuhiko Wakayama, Hideharu Moru, Naoyoshi Sato, Yoshihito Hirai, Toshihisa Murayoshi
  • Patent number: 7799147
    Abstract: The performance index ??×Q of a magnetic core member, in which an Fe—Si—Cr alloy is used, is further improved. A flaky soft magnetic metal powder, which is used in a magnetic core member for an RFID antenna comprising the above flaky soft magnetic metal powder and a binder, wherein it is composed of an Fe—Si—Cr alloy having an Ms (saturation magnetization)/Hc (coercive force) of 0.8 to 1.5 (mT/Am?1) in an applied magnetic field of 398 kA/m. In the present invention, it is preferable that the flaky soft magnetic metal powder consists of 7 to 23 at % of Si, 15 at % or less of Cr (excluding 0), and the balance being Fe and inevitable impurities, and that it has a weight-average particle size D50 of 5 to 30 ?m and an average thickness of 0.1 to 1 ?m.
    Type: Grant
    Filed: March 15, 2007
    Date of Patent: September 21, 2010
    Assignee: TDK Corporation
    Inventors: Atsuhito Matsukawa, Katsuhiko Wakayama, Yoshihito Hirai
  • Publication number: 20090267017
    Abstract: A flat soft magnetic material to be used for a noise-suppressing magnetic sheet, wherein the 50% particle size D50 (?m), coercive force Hc (A/m) and bulk density BD (Mg/m3) of the flat soft magnetic material satisfy the following formula (1). D50/(HC×BD)?1.
    Type: Application
    Filed: April 20, 2009
    Publication date: October 29, 2009
    Applicant: TDK Corporation
    Inventors: Atsuhito Matsukawa, Katsuhiko Wakayama, Hideharu Moro, Naoyoshi Sato, Yoshihito Hirai, Toshihisa Murayoshi
  • Patent number: 7378036
    Abstract: A ferrite material of the present invention is configured such that 0.05 to 1.0 wt % of bismuth oxide in terms of Bi2O3, 0.5 to 3.0 wt % of tin oxide in terms of SnO2, and 30 to 5000 wt ppm of chromium oxide in terms of Cr2O3 are added to a predetermined main component mixture composition. Therefore, it is possible to achieve an improvement in DC bias characteristics, an improvement in temperature characteristics of initial magnetic permeability, and an improvement in resistivity and further achieve an improvement in burned body strength, particularly in burned body flexural strength (bending strength).
    Type: Grant
    Filed: October 26, 2005
    Date of Patent: May 27, 2008
    Assignee: TDK Corporation
    Inventors: Ryuichi Wada, Takuya Aoki, Atsuhito Matsukawa, Kensaku Asakura
  • Publication number: 20070221297
    Abstract: The performance index ??×Q of a magnetic core member, in which an Fe—Si—Cr alloy is used, is further improved. A flaky soft magnetic metal powder, which is used in a magnetic core member for an RFID antenna comprising the above flaky soft magnetic metal powder and a binder, wherein it is composed of an Fe—Si—Cr alloy having an Ms (saturation magnetization)/Hc (coercive force) of 0.8 to 1.5 (mT/Am?1) in an applied magnetic field of 398 kA/m. In the present invention, it is preferable that the flaky soft magnetic metal powder consists of 7 to 23 at % of Si, 15 at % or less of Cr (excluding 0), and the balance being Fe and inevitable impurities, and that it has a weight-average particle size D50 of 5 to 30 ?m and an average thickness of 0.1 to 1 ?m.
    Type: Application
    Filed: March 15, 2007
    Publication date: September 27, 2007
    Applicant: TDK CORPORATION
    Inventors: Atsuhito Matsukawa, Katsuhiko Wakayama, Yoshihito Hirai
  • Publication number: 20060116283
    Abstract: A ferrite material of the present invention is configured such that 0.05 to 1.0 wt % of bismuth oxide in terms of Bi2O3, 0.5 to 3.0 wt % of tin oxide in terms of SnO2, and 30 to 5000 wt ppm of chromium oxide in terms of Cr2O3 are added to a predetermined main component mixture composition. Therefore, it is possible to achieve an improvement in DC bias characteristics, an improvement in temperature characteristics of initial magnetic permeability, and an improvement in resistivity and further achieve an improvement in burned body strength, particularly in burned body flexural strength (bending strength).
    Type: Application
    Filed: October 26, 2005
    Publication date: June 1, 2006
    Applicant: TDK Corporation
    Inventors: Ryuichi Wada, Takuya Aoki, Atsuhito Matsukawa, Kensaku Asakura
  • Patent number: 5498361
    Abstract: For the purpose of improving the initial magnetic permeability of manganese-zinc system ferrite in the high-frequency band of 10 kHz to 500 kHz, a manganese-zinc system ferrite comprising 50-56 mol % of Fe.sub.2 O.sub.3, 22-39 mol % of MnO, and 8-25 mol % of ZnO is fired after adding thereto up to 800 ppm calculated as Bi.sub.2 O.sub.3 of a bismuth oxide component and up to 1,200 ppm calculated as MoO.sub.3 of a molybdenum oxide component in admixture. It has an average grain diameter of from 5 to 50 .mu.m.
    Type: Grant
    Filed: August 8, 1994
    Date of Patent: March 12, 1996
    Assignee: TDK Corporation
    Inventors: Atsuhito Matsukawa, Shoji Inoue