Patents by Inventor Kenji Sakane

Kenji Sakane 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: 11264155
    Abstract: An object of the present invention is to provide a magnetic powder having a narrow particle size distribution of epsilon-type iron oxide particles, and another object is to provide magnetic powder suitable for magnetic recording medium by improving particle size distribution, and provide epsilon-type iron oxide magnetic particles and related technologies in which a number average particle diameter of major diameters (D50) is 10 to 20 nm, a 90% cumulative particle diameter (D90) is 30 nm or less, and a geometric standard deviation (?g) of major diameters is 1.45 or less, which are obtained by TEM observation.
    Type: Grant
    Filed: September 29, 2017
    Date of Patent: March 1, 2022
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Kazuhiro Yamaga, Tetsuya Kawahito, Toshihiko Ueyama, Kenji Sakane
  • Publication number: 20210300779
    Abstract: [Problem] To provide a method for producing iron based oxide magnetic powder that has a narrow particle size distribution and a small content of fine particles that do not contribute to the magnetic recording characteristics, and consequently has a narrow coercive force distribution and is suitable for the enhancement of the recording density of the magnetic recording medium. [Solution] ?-Type iron based oxide magnetic powder is obtained by a wet method, then a tetraalkylammonium salt as a surface modifier is added to a slurry containing the magnetic powder to make a concentration of 0.009 mol/kg or more and 1.0 mol/kg or less, and simultaneously to make pH of 11 or more and 14 or less, and the slurry is subjected to a dispersion treatment and then classified, so as to provide iron based oxide magnetic powder having a narrow particle size distribution and a narrow coercive force distribution.
    Type: Application
    Filed: March 26, 2019
    Publication date: September 30, 2021
    Inventors: Shin-ichi OHKOSHI, Asuka NAMAI, Kenji SAKANE, Tetsuya KAWAHITO
  • Patent number: 11097956
    Abstract: A surface-modified iron-based oxide magnetic particle powder has good solid-liquid separation property in the production process, has good dispersibility in a coating material for forming a coating-type magnetic recording medium, has good orientation property, and has a small elution amount of a water-soluble alkali metal, and to provide a method for producing the surface-modified iron-based oxide magnetic particle powder. The surface-modified iron-based oxide magnetic particle powder can be obtained by neutralizing a solution containing dissolved therein a trivalent iron ion and an ion of the metal, by which the part of Fe sites is to be substituted, with an alkali aqueous solution, so as to provide a precursor, coating a silicon oxide on the precursor, heating the precursor to provide e-type iron-based oxide magnetic powder, and adhering a hydroxide or a hydrous oxide of one kind or two kinds of Al and Y thereto.
    Type: Grant
    Filed: March 11, 2016
    Date of Patent: August 24, 2021
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Kenji Sakane, Tetsuya Kawahito
  • Patent number: 10919778
    Abstract: A method for making iron-based oxide magnetic particle powders having particular peak intensity and diffraction intensities, comprising neutralizing an aqueous solution containing a trivalent iron ion, alone or with a substituting metal (M), a step of adding hydroxycarboxylic acid to the neutralized solution to create a second solution including the hydroxycarboxylic acid D, another neutralizing step for the second solution, a coating step of silicon oxide coating iron oxyhydroxide with or without the substituted metal element found in the second neutralized solution, and heating the coated iron oxyhydroxide with or without the substituted metal element to form a silicon oxide coated iron oxide with or without the substituted metal element. After the second neutralization step, there is no water washing. As a result, the molar ratio D/(Fe+M) is between 0.125 and 1.0 and the silicon oxide coating can be uniform and the formation reaction of the hydroxide is not retarded.
    Type: Grant
    Filed: July 26, 2016
    Date of Patent: February 16, 2021
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Kenji Sakane, Tetsuya Kawahito
  • Patent number: 10622127
    Abstract: An iron-based oxide magnetic particle powder has a narrow particle size distribution a small content of fine particles that do not contribute to magnetic recording characteristics, and a narrow coercive force distribution, to enhance magnetic recording medium density. Neutralizing an aqueous solution containing a trivalent iron ion and an ion of the metal substituting a part of the Fe sites by adding an alkali to make pH of 1.5 or more and 2.5 or less, adding a hydroxycarboxylic acid, and further neutralizing by adding an alkali to make pH of 8.0 or more and 9.0 or less are performed at 5° C. or more and 25° C. or less. A formed iron oxyhydroxide precipitate containing the substituting metal element is rinsed with water, then coated with silicon oxide, and then heated thereby providing e-type iron-based oxide magnetic particle powder. The rinsed precipitate may be subjected to a hydrothermal treatment.
    Type: Grant
    Filed: December 28, 2015
    Date of Patent: April 14, 2020
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Kenji Sakane, Tetsuya Kawahito
  • Patent number: 10504548
    Abstract: An e-type iron-based oxide magnetic particle powder has narrow particle size distribution and has a low content of fine particles which do not contribute to magnetic recording characteristics. As a result, a narrow coercive force distribution is achieved and the powder is suitable for increasing recording density of a magnetic recording medium. The powder containing substituting metal elements can be obtained by: adding an alkali to an aqueous solution containing trivalent iron ions and ions of the metals for partially substituting Fe sites to neutralize the aqueous solution to a pH of 1.5 to 2.5; then adding a hydroxycarboxylic acid; further adding the alkali to neutralize the aqueous solution to a pH of 8.0 to 9.0; washing with water a precipitation of an iron oxyhydroxide containing the substituting metal elements produced; and coating the iron oxyhydroxide containing the substituting metal elements with a silicon oxide and heating the resultant.
    Type: Grant
    Filed: September 17, 2015
    Date of Patent: December 10, 2019
    Assignee: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Kenji Sakane, Tetsuya Kawahito
  • Publication number: 20190228889
    Abstract: An object of the present invention is to provide a magnetic powder having a narrow particle size distribution of epsilon-type iron oxide particles, and another object is to provide magnetic powder suitable for magnetic recording medium by improving particle size distribution, and provide epsilon-type iron oxide magnetic particles and related technologies in which a number average particle diameter of major diameters (D50) is 10 to 20 nm, a 90% cumulative particle diameter (D90) is 30 nm or less, and a geometric standard deviation (?g) of major diameters is 1.45 or less, which are obtained by TEM observation.
    Type: Application
    Filed: September 29, 2017
    Publication date: July 25, 2019
    Applicant: DOWA ELECTRONICS MATERIALS CO., LTD.
    Inventors: Kazuhiro YAMAGA, Tetsuya KAWAHITO, Toshihiko UEYAMA, Kenji SAKANE
  • Publication number: 20180208479
    Abstract: To provide iron-based oxide magnetic particle powder that has a narrow particle size distribution and a small content of fine particles that do not contribute to the magnetic recording characteristics, which result in a narrow coercive force distribution, and is suitable for the enhancement of the recording density of the magnetic recording medium, and a method for producing the same. An alkali is added to an aqueous solution containing a trivalent iron ion and an ion of the metal substituting a part of Fe sites to neutralize the aqueous solution to pH of 1.0 or more and 3.0 or less; a hydroxycarboxylic acid D is added in an amount providing a molar ratio D/Fe with respect to the amount of the trivalent iron ion or a molar ratio (D/(Fe+M)) with respect to the total amount of the trivalent iron ion and the ion of the metal M in the case where the substituting metal ion is contained of 0.125 or more and 1.0 or less; an alkali is further added to neutralize to pH of 7.0 or more and 10.
    Type: Application
    Filed: July 26, 2016
    Publication date: July 26, 2018
    Inventors: Kenji SAKANE, Tetsuya KAWAHITO
  • Publication number: 20180033528
    Abstract: A surface-modified iron-based oxide magnetic particle powder has good solid-liquid separation property in the production process, has good dispersibility in a coating material for forming a coating-type magnetic recording medium, has good orientation property, and has a small elution amount of a water-soluble alkali metal, and to provide a method for producing the surface-modified iron-based oxide magnetic particle powder. The surface-modified iron-based oxide magnetic particle powder can be obtained by neutralizing a solution containing dissolved therein a trivalent iron ion and an ion of the metal, by which the part of Fe sites is to be substituted, with an alkali aqueous solution, so as to provide a precursor, coating a silicon oxide on the precursor, heating the precursor to provide e-type iron-based oxide magnetic powder, and adhering a hydroxide or a hydrous oxide of one kind or two kinds of Al and Y thereto.
    Type: Application
    Filed: March 11, 2016
    Publication date: February 1, 2018
    Inventors: Kenji SAKANE, Tetsuya KAWAHITO
  • Publication number: 20180005737
    Abstract: An iron-based oxide magnetic particle powder has a narrow particle size distribution a small content of fine particles that do not contribute to magnetic recording characteristics, and a narrow coercive force distribution, to enhance magnetic recording medium density. Neutralizing an aqueous solution containing a trivalent iron ion and an ion of the metal substituting a part of the Fe sites by adding an alkali to make pH of 1.5 or more and 2.5 or less, adding a hydroxycarboxylic acid, and further neutralizing by adding an alkali to make pH of 8.0 or more and 9.0 or less are performed at 5° C. or more and 25° C. or less. A formed iron oxyhydroxide precipitate containing the substituting metal element is rinsed with water, then coated with silicon oxide, and then heated thereby providing e-type iron-based oxide magnetic particle powder. The rinsed precipitate may be subjected to a hydrothermal treatment.
    Type: Application
    Filed: December 28, 2015
    Publication date: January 4, 2018
    Inventors: Kenji SAKANE, Tetsuya KAWAHITO
  • Publication number: 20170287516
    Abstract: An e-type iron-based oxide magnetic particle powder has narrow particle size distribution and has a low content of fine particles which do not contribute to magnetic recording characteristics. As a result, a narrow coercive force distribution is achieved and the powder is suitable for increasing recording density of a magnetic recording medium. The powder containing substituting metal elements can be obtained by: adding an alkali to an aqueous solution containing trivalent iron ions and ions of the metals for partially substituting Fe sites to neutralize the aqueous solution to a pH of 1.5 to 2.5; then adding a hydroxycarboxylic acid; further adding the alkali to neutralize the aqueous solution to a pH of 8.0 to 9.0; washing with water a precipitation of an iron oxyhydroxide containing the substituting metal elements produced; and coating the iron oxyhydroxide containing the substituting metal elements with a silicon oxide and heating the resultant.
    Type: Application
    Filed: September 17, 2015
    Publication date: October 5, 2017
    Inventors: Kenji SAKANE, Tetsuya KAWAHITO
  • Patent number: 9683168
    Abstract: To reduce impurity contents of carbon and oxygen not contributing to light emission, then suppress deterioration of emission intensity of a phosphor, and improve emission efficiency of this phosphor. Therefore, there is provided a firing method of nitride or oxynitride phosphors, wherein a crucible 11 made of nitride is used as a firing container, and firing is performed, with this crucible covered with a lid (container 10), to manufacture the phosphor. The phosphor is expressed by a general composition formula MABOoN3-2/3O:Z in which element M is one or more kinds of elements having bivalent valency, element A is one or more kinds of elements having tervalent valency, element B is one or more kinds of elements having tetravalent valency, O is oxygen, N is nitrogen, and element Z is an activating agent, satisfying o?0.
    Type: Grant
    Filed: September 7, 2007
    Date of Patent: June 20, 2017
    Assignees: NICHIA CORPORATION, CITIZEN ELECTRONICS CO., LTD.
    Inventors: Masahiro Gotoh, Kenji Sakane
  • Patent number: 8475682
    Abstract: To provide a phosphor for manufacturing an one chip type LED illumination, etc, by combining a near ultraviolet/ultraviolet LED and a blue LED, and having an excellent emission efficiency including luminance. The phosphor is given as a general composition formula expressed by MmAaBbOoNn:Z, (where element M is one or more kinds of elements having bivalent valency, element A is one or more kinds of elements having tervalent valency, element B is one or more kinds of elements having tetravalent valency, O is oxygen, N is nitrogen, and element Z is one or more kinds of elements acting as an activator.), satisfying a=(1+x)×m, b=(4?x)×m, o=x×m, n=(7?x)×m, 0?x?1, wherein when excited by light in a wavelength range from 300 nm to 500 nm, the phosphor has an emission spectrum with a peak wavelength in a range from 500 nm to 620 nm.
    Type: Grant
    Filed: October 24, 2011
    Date of Patent: July 2, 2013
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Akira Nagatomi, Kenji Sakane, Tomoya Yamada
  • Patent number: 8441180
    Abstract: A phosphor having an excitation band relative to lights in the wide range of wavelengths from ultraviolet to visible light, and having an emission spectrum in the red range and so on, with a wide half value width, and an LED and a light source using the phosphor and emitting white and other color lights with good color rendering properties are provided. Powdered raw materials of Ca3N2 (2N), CaO (2N), AlN (3N), Si3N4 (3N), and Eu2O3 (3N) are prepared, and the respective raw materials are mixed to have a mole ratio of the respective elements of Ca:Al:Si:Eu=0.985:1:1:0.015. The mixed raw materials are fired at 1000° C. or higher in an inert atmosphere for three hours, and thereafter pulverized to obtain a phosphor having a composition of CaAlSiN2.83O0.25:Eu, which is one example of the phosphor satisfying the above described object.
    Type: Grant
    Filed: January 3, 2011
    Date of Patent: May 14, 2013
    Assignees: Dowa Electronics Materials Co., Ltd., Nichia Corporation
    Inventors: Akira Nagatomi, Masahiro Gotoh, Kenji Sakane, Shuji Yamashita
  • Patent number: 8372309
    Abstract: To provide a phosphor having an emission spectrum with a broad peak in a range from green color to yellow color, having a broad and flat excitation band capable of using lights of broad range from near ultraviolet/ultraviolet to blue lights as excitation lights, and having excellent emission efficiency and luminance. The problem is solved by providing the phosphor expressed by a general composition formula MmAaBbOoNn:Z (where element M is one or more kinds of elements having bivalent valency, element A is one or more kinds of elements having tervalent valency, element B is one or more kinds of elements having tetravalent valency, O is oxygen, N is nitrogen, and element Z is one or more kinds of elements acting as the activator), satisfying 4.0<(a+b)/m<7.0, a/m?0.5, b/a>2.5, n>o, n=2/3m+a+4/3b?2/3o, and having an emission spectrum with a peak wavelength of 500 nm to 650 nm when excited by light in a wavelength range from 300 nm to 500 nm.
    Type: Grant
    Filed: October 26, 2010
    Date of Patent: February 12, 2013
    Assignee: Mitsubishi Chemical Corporation
    Inventors: Akira Nagatomi, Kenji Sakane
  • Publication number: 20130026908
    Abstract: Provided is the phosphor expressed by a general composition formula MmAaBbOoNn:Z (where element M is one or more kinds of elements having bivalent valency, element A is one or more kinds of elements having tervalent valency, element B is one or more kinds of elements having tetravalent valency, O is oxygen, N is nitrogen, and element Z is one or more kinds of activators.), satisfying 4.0<(a+b)/m<7.0, a/m?0.5, b/a>2.5, n>o, n=2/3m+a+4/3b?2/3o, and having an emission spectrum with a peak wavelength of 500 nm to 650 nm when excited by light in a wavelength range from 300 nm to 500 nm.
    Type: Application
    Filed: September 14, 2012
    Publication date: January 31, 2013
    Applicant: Mitsubishi Chemical Corporation
    Inventors: Akira NAGATOMI, Kenji Sakane
  • Patent number: RE44162
    Abstract: To provide a phosphor for an electron beam excitation with a small deterioration in an emission efficiency and capable of maintaining a high luminance, even when an excitation density of an electron beam for a phosphor excitation is increased. As raw materials, Ca3N2(2N), AlN(3N), Si3N4(3N), and Eu2O3(3N) are prepared, and the raw materials thus prepared are measured and mixed, so that a molar ratio of each element becomes (Ca+Eu):Al:Si=1:1:1. Then, the mixture thus obtained is maintained and fired for at 1500° C. for 3 hours, and thereafter crushed, to manufacture the phosphor having a composition formula Ca0.985SiAlN3:Eu0.015.
    Type: Grant
    Filed: May 4, 2011
    Date of Patent: April 23, 2013
    Assignees: Dowa Electronics Materials Co., Ltd., Nichia Corporation
    Inventors: Masahiro Gotoh, Akira Nagatomi, Kenji Sakane, Shuji Yamashita
  • Patent number: RE44996
    Abstract: A phosphor including a main production phase of a phosphor expressed by a composition formula of MmAaBbOoNn:Zz (where an element M is one or more bivalent elements, an element A is one or more trivalent elements, an element B is one or more tetravalent elements, O is oxygen, N is nitrogen, an element Z is an activator, n=2/3m+a+4/3b?2/3o, m/(a+b)?1/2, (o+n)/(a+b)>4/3, wherein m=a=b=1 and o and n is not 0). A phosphor including 24 wt % to 30 wt % of Ca (calcium), 17 wt % to 21 wt % of Al (aluminum), 18 wt % to 22 wt % of Si (silicon), 1 wt % to 15 wt % of oxygen, 15 wt % to 33 wt % of nitrogen and 0.01 wt % to 10 wt % of Eu (europium), wherein an emission maximum in an emission spectrum is in a range of 600 nm to 660 nm; and wherein color chromaticity x of light emission is in a range of 0.5 to 0.7, and color chromaticity y of the light emission is in a range of 0.3 to 0.5.
    Type: Grant
    Filed: March 7, 2012
    Date of Patent: July 8, 2014
    Assignees: Nichia Corporation, Dowa Electronics Materials Co., Ltd.
    Inventors: Akira Nagatomi, Masahiro Gotoh, Kenji Sakane, Shuji Yamashita
  • Patent number: RE45502
    Abstract: To provide a phosphor having a broad emission spectrum with a peak in the range from yellow color to red color (wavelength from 570 nm to 620 nm), having a flat excitation band with large area on the long wavelength side from near ultraviolet/ultraviolet to green color (wavelength from 250 nm to 550 nm), and excellent in emission intensity and luminance, and a method of manufacturing the same, and also a light source such as white LED using the phosphor. As raw materials, Ca3N2(2N), AlN(3N), Si3N4(3N), and Eu2O3(3N) are prepared, and out of each raw material, 0.950/3 mol of Ca3N2, 2 mol of AlN, 4/3 mol of Si3N4, and 0.050/2 mol of Eu2O3 are weighed, and the raw materials thus weighed are mixed by using a mortar. The raw materials thus mixed are put in a BN crucible, and retained/fired for 3 hours at 1700° C. in a nitrogen atmosphere, and thereafter cooled from 1700° C. to 200° C., to thereby obtain the phosphor expressed by a composition formula Ca0.950Al2Si4O0.075N7.917:Eu0.050.
    Type: Grant
    Filed: March 7, 2012
    Date of Patent: May 5, 2015
    Assignees: Dowa Electronics Materials Co., Ltd., Nichia Corporation
    Inventors: Kenji Sakane, Akira Nagatomi
  • Patent number: RE45640
    Abstract: A phosphor, which has less reduction in emission efficiency and is capable of keeping high luminance even when density of an electron beam for exciting the phosphor increases, is provided. As raw materials, Ca3N2 (2N), AlN (3N), Si3N4 (3N), and Eu2O3 (3N) are prepared, and each of the raw materials is weighed so that a mole ratio of each element is, for example, (Ca+Eu):Al:Si=1:1:1, and mixed, then the mixture is held and fired at 1500° C. under the inert atmosphere for three hours, and thereafter ground to produce a phosphor having a composition formula of Ca0.985SiAlN3:Eu0.015.
    Type: Grant
    Filed: March 9, 2012
    Date of Patent: August 4, 2015
    Assignees: DOWA ELECTRONICS MATERIALS CO., LTD., NICHIA CORPORATION
    Inventors: Masahiro Gotoh, Akira Nagatomi, Kenji Sakane, Shuji Yamashita