Patents by Inventor Yukio Hamaji

Yukio Hamaji 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: 6769160
    Abstract: A process for manufacturing an electronic part having a ceramic body and an outer electrode form on the surface of the body, the outer electrode including a plurality of layers and having a Sn plating layer as the outermost layer. The Sn plating layer having an average crystal grain size of about 1 &mgr;m or less is formed on a Ni or Ni alloy by electroplating in a plating bath having a pH of about 3 to 10.
    Type: Grant
    Filed: March 5, 2002
    Date of Patent: August 3, 2004
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Shoichi Higuchi, Tatsuo Kunishi, Yukio Hamaji
  • Patent number: 6500327
    Abstract: An Sn—Bi alloy plating bath has a pH about 2.0 to 9.0 and comprises Bi3+ ions, Sn2+ ions, complexing agent (I) and complexing agent (II). Complexing agent (I) can be (a) aliphatic dicarboxylic acids having alkyl groups of 1-3 carbon atoms, (b) aliphatic hydroxymonocarboxylic acids having alkyl groups of 1-3 carbon atoms, (c) aliphatic hydroxypolycarboxylic acids having alkyl groups of 1-4 carbon atoms, (d) monosaccharides, polyhydroxycarboxylic acids produced by partially oxidizing the monosaccharides, and their cyclic ester compounds, and (e) condensed phosphoric acids. Complexing Agent (II) can be (s) ethylenediamineteraacetic acid (EDTA), (t) nitrilotriacetic acid (NTA), and (u) trans-1,2-cyclohexanediaminetetraacetic acid (CyDTA).
    Type: Grant
    Filed: February 3, 2000
    Date of Patent: December 31, 2002
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Junichi Saitoh, Tatsuo Kunishi, Yukio Hamaji
  • Patent number: 6489257
    Abstract: A dielectric ceramic material containing BaTiO3 as a primary component and a rare earth element as an additional component, wherein the material satisfies the relation 0.7≦M/N so as to make the density of the rare earth metal uniform between crystal grains, and the material satisfies the relation 0.8≦L/M so as to make the density of the rare earth metal uniform in a crystal grain. In these relations, M represents the number of crystal grains satisfying the relation 0.5≦Di/D; N represents the number of crystal grains constituting the ceramic material; and L represents the number of crystal grains satisfying the relations 0.5≦Di/D and Si/Di≦0.3, wherein Di represents the mean density of the rare earth element in an arbitrary crystal grain i, D represents the mean density of the rare earth element in the entirety of the ceramic material, and Si represents the standard deviation of the density of the rare earth element in the crystal grain i.
    Type: Grant
    Filed: August 18, 2000
    Date of Patent: December 3, 2002
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Takashi Hiramatsu, Jun Ikeda, Hiroyuki Wada, Yukio Hamaji
  • Publication number: 20020135972
    Abstract: An electronic part comprises a body and an outer electrode formed on the surface of the body, the outer electrode comprising a plurality of layers and having a Sn plating layer as the outermost layer. The Sn plating layer has an average crystal grain size of about 1 &mgr;m or less.
    Type: Application
    Filed: March 5, 2002
    Publication date: September 26, 2002
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Shoichi Higuchi, Tatsuo Kunishi, Yukio Hamaji
  • Patent number: 6416603
    Abstract: Disclosed is a monolithic ceramic capacitor composed of plural dielectric ceramic layers made of a ceramic material comprising strontium titanate and bismuth oxide or the like, plural inner electrodes made of a base metal material comprising nickel or a nickel alloy, which are laminated via the dielectric ceramic layer to produce the electrostatic capacity of the capacitor, and outer electrodes as electrically connected with the inner electrodes. Each dielectric ceramic layer in the capacitor contains a reduction inhibitor, for example aMO+bMnO2+cB2O3+(100−a−b−c)SiO2 (where M is at least one of Mg, Sr, Ca and Ba; and a, b and c each are, in % by mol, 10≦a≦60, 5≦b≦20 and 20≦c≦35). In producing the capacitor, the laminate of dielectric ceramic layers may be fired in a neutral or reducing atmosphere without being reduced.
    Type: Grant
    Filed: December 16, 1998
    Date of Patent: July 9, 2002
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Toshiki Nishiyama, Yukio Hamaji
  • Patent number: 6411495
    Abstract: The present invention provides a dielectric ceramic composition whose electrostatic capacity has an excellently low temperature dependence; which can be fired in a reducing atmosphere; and which is advantageously used in a laminated ceramic capacitor having an internal electrode formed of a base metal such as nickel or nickel alloy. The dielectric ceramic composition is represented by the following formula: {Ba1-xCaxO}mTiO2+&agr;MgO+&bgr;MnO, wherein 0.001≦&agr;≦0.05; 0.001≦&bgr;≦0.025; 1.000<m≦1.035; and 0.02≦x≦0.15.
    Type: Grant
    Filed: February 2, 2001
    Date of Patent: June 25, 2002
    Assignee: Murata Manufacturing Co. Ltd.
    Inventors: Nobuyuki Wada, Jun Ikeda, Takashi Hiramatsu, Yukio Hamaji
  • Patent number: 6383323
    Abstract: A dielectric ceramic which exhibits small variation in dielectric constant, allows use of a base metal, can be fired in a reducing atmosphere and which is suitable for constituting a dielectric ceramic layer for, e.g., a laminated ceramic capacitor is obtained by firing barium titanate powder in which the c-axis/a-axis ratio in the perovskite structure is about 1.000 or more and less than about 1.003 and the amount of OH groups in the crystal lattice is about 2.0 wt. % or less. The barium titanate powder starting material preferably has a maximum particle size of about 0.3 &mgr;m or less and an average particle size of about 0.05-0.15 &mgr;m. Each particle of the barium titanate powder preferably comprises a low-crystallinity portion and a high-crystallinity portion, the diameter of the low-crystallinity portion being about 0.5 times or more the particle size of the powder.
    Type: Grant
    Filed: August 23, 2001
    Date of Patent: May 7, 2002
    Assignee: Murata Manufacturing Corp. Ltd.
    Inventors: Nobuyuki Wada, Takashi Hiramatsu, Jun Ikeda, Yukio Hamaji
  • Patent number: 6373683
    Abstract: An electronic part includes a body and an outer electrode formed on the surface of the body, the outer electrode comprising a plurality of layers and having a Sn plating layer as the outermost layer. The Sn plating layer has an average crystal grain size of about 1 &mgr;m or less.
    Type: Grant
    Filed: October 6, 2000
    Date of Patent: April 16, 2002
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Shoichi Higuchi, Tatsuo Kunishi, Yukio Hamaji
  • Publication number: 20020020483
    Abstract: A dielectric ceramic which exhibits small variation in dielectric constant, allows use of a base metal, can be fired in a reducing atmosphere and which is suitable for constituting a dielectric ceramic layer for, e.g., a laminated ceramic capacitor is obtained by firing barium titanate powder in which the c-axis/a-axis ratio in the perovskite structure is about 1.000 or more and less than about 1.003 and the amount of OH groups in the crystal lattice is about 2.0 wt. % or less. The barium titanate powder starting material preferably has a maximum particle size of about 0.3 &mgr;m or less and an average particle size of about 0.05-0.15 &mgr;m. Each particle of the barium titanate powder preferably comprises a low-crystallinity portion and a high-crystallinity portion, the diameter of the low-crystallinity portion being about 0.5 times or more the particle size of the powder.
    Type: Application
    Filed: August 23, 2001
    Publication date: February 21, 2002
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Nobuyuki Wada, Takashi Hiramatsu, Jun Ikeda, Yukio Hamaji
  • Publication number: 20010036896
    Abstract: The present invention provides a dielectric ceramic composition whose electrostatic capacity has an excellently low temperature dependence; which can be fired in a reducing atmosphere; and which is advantageously used in a laminated ceramic capacitor having an internal electrode formed of a base metal such as nickel or nickel alloy. The dielectric ceramic composition is represented by the following formula: {Ba1-xCaxO}mTiO2+&agr;MgO+&bgr;MnO, wherein 0.001≦&agr;≦0.05; 0.001≦&bgr;≦0.025; 1.000<m≦1.035; and 0.02≦x≦0.15.
    Type: Application
    Filed: February 2, 2001
    Publication date: November 1, 2001
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Nobuyuki Wada, Jun Ikeda, Takashi Hiramatsu, Yukio Hamaji
  • Patent number: 6303529
    Abstract: A dielectric ceramic which exhibits small variation in dielectric constant, allows use of a base metal, can be fired in a reducing atmosphere and which is suitable for constituting a dielectric ceramic layer for, e.g., a laminated ceramic capacitor is obtained by firing barium titanate powder in which the c-axis/a-axis ratio in the perovskite structure is about 1.000 or more and less than about 1.003 and the amount of OH groups in the crystal lattice is about 2.0 wt. % or less. The barium titanate powder starting material preferably has a maximum particle size of about 0.3 &mgr;m or less and an average particle size of about 0.05-0.15 &mgr;m. Each particle of the barium titanate powder preferably comprises a low-crystallinity portion and a high-crystallinity portion, the diameter of the low-crystallinity portion being about 0.5 times or more the particle size of the powder.
    Type: Grant
    Filed: January 20, 1999
    Date of Patent: October 16, 2001
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Nobuyuki Wada, Takashi Hiramatsu, Jun Ikeda, Yukio Hamaji
  • Patent number: 6295196
    Abstract: A monolithic ceramic electronic component includes a laminate including a plurality of ceramic layers obtained by sintering a ceramic raw material powder, and a plurality of internal electrodes located between the ceramic layers and obtained by sintering a metallic powder. The ceramic layers have a thickness of about 3 &mgr;m or less and are composed of ceramic grains having an average particle diameter of more than about 0.5 &mgr;m, the particle diameter of the ceramic grains in the thickness direction of the ceramic layers is smaller than the thickness of the ceramic layers, and the internal electrodes have a thickness of about 0.2 to 0.7 &mgr;m.
    Type: Grant
    Filed: July 6, 2000
    Date of Patent: September 25, 2001
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Yukio Hamaji, Nobuyuki Wada, Tsuyoshi Yamana, Takanori Nakamura
  • Publication number: 20010013388
    Abstract: A laminated ceramic electronic part such as a multilayer ceramic capacitor having a long mean life and an excellent reliability can be provided, even when the thicknesses of the ceramic layers are about 3 &mgr;m or less. For that purpose, the arithmetic mean roughness (Ra) of the interfaces between the internal electrodes and the ceramic layers is made to be about 200 nm or less, and the area rate of pores in a cross-sectional area of the ceramic layers is made to be about 1% or less. Preferably, the arithmetic mean roughness (Ra) of the surface of a ceramic green sheet used for obtaining the ceramic layers is made to be about 100 nm or less, and the internal electrodes are composed of metal films formed by a thin film forming method.
    Type: Application
    Filed: February 2, 2001
    Publication date: August 16, 2001
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Takaharu Miyazaki, Tsuyoshi Yamana, Yukio Hamaji
  • Patent number: 6243254
    Abstract: Provided is a highly reliable laminated ceramic capacitor in which decrease of dielectric constant under a high electric field is small and which satisfies the B-grade and X7R grade characteristics, using Ni for the inner electrodes, wherein the dielectric material contains about 0.2 to 5.0 parts by weight of Li2O—(Si, Ti)2—MO oxides (MO is at least one of the compounds of Al2O3 and ZrO2) or SiO2—TiO2—XO oxides (XO is at least one of the compounds of BaO, CaO, SrO, MgO, ZnO and MnO) relative to 100 parts by weight of a principal component represented by (Ba1−xCaxO)mTiO2+&agr;Re2O3+&bgr;MgO+&ggr;MnO (Re2O3 represents at least one of Y2O3, Gd2O3, Tb2O3, Dy2O3, Ho2O3, Er2O3 and Yb2O3).
    Type: Grant
    Filed: August 6, 1999
    Date of Patent: June 5, 2001
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Nobuyuki Wada, Masamitsu Shibata, Takashi Hiramatsu, Yukio Hamaji
  • Patent number: 6225250
    Abstract: The present invention provides a dielectric ceramic composition whose electrostatic capacity has an excellently low temperature dependence; which can be fired in a reducing atmosphere; and which is advantageously used in a laminated ceramic capacitor having an internal electrode formed of a base metal such as nickel or nickel alloy. The dielectric ceramic composition is represented by the following formula: {Ba1−xCaxO}mTiO2+&agr;MgO+&bgr;MnO, wherein 0.001≦&agr;≦0.05; 0.001≦&bgr;≦0.025; 1.000<m≦1.035; and 0.02≦x≦0.15.
    Type: Grant
    Filed: February 17, 1999
    Date of Patent: May 1, 2001
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Nobuyuki Wada, Jun Ikeda, Takashi Hiramatsu, Yukio Hamaji
  • Patent number: 6205015
    Abstract: A dielectric ceramic which exhibits an excellent electrostatic capacity-temperature characteristic; which allows use of a base metal such as nickel; which can be fired in a reducing atmosphere; and which is suitable for constituting a dielectric ceramic layer of a laminated ceramic electronic element such as a laminated ceramic capacitor; is obtained by firing barium titanate powder in which the c-axis/a-axis ratio in the perovskite structure is in the range of about 1.003 to 1.010 and the amount of OH groups in the crystal lattice is about 1 wt. % or less. The barium titanate powder a starting material preferably has a maximum particle size of about 0.5 &mgr;m or less and an average particle size of about 0.1-0.3 &mgr;m, and individual particles of the barium titanate powder comprise a low-crystallinity portion 21 and a high-crystallinity portion 23, with the diameter of the low-crystallinity portion being less than about 0.65 times the particle size of the powder.
    Type: Grant
    Filed: January 20, 1999
    Date of Patent: March 20, 2001
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Nobuyuki Wada, Jun Ikeda, Takashi Hiramatsu, Yukio Hamaji
  • Patent number: 6143109
    Abstract: A multilayer ceramic capacitor and a process for producing the same, which comprises dielectric ceramic layers, internal electrodes disposed between the dielectric ceramic layers, and an external electrode connected to the internal electrodes, the dielectric ceramic layers comprising barium titanate, a bismuth compound, and an anti-reducing agent, the internal electrodes comprising nickel or a nickel alloy.
    Type: Grant
    Filed: May 22, 1998
    Date of Patent: November 7, 2000
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Harunobu Sano, Yukio Hamaji
  • Patent number: 5879812
    Abstract: Disclosed is a monolithic ceramic capacitor composed of plural dielectric ceramic layers made of a ceramic material comprising strontium titanate and bismuth oxide or the like, plural inner electrodes made of a base metal material comprising nickel or a nickel alloy, which are laminated via the dielectric ceramic layer to produce the electrostatic capacity of the capacitor, and outer electrodes as electrically connected with the inner electrodes. Each dielectric ceramic layer in the capacitor contains a reduction inhibitor, for example aMO+bMnO.sub.2 +cB.sub.2 O.sub.3 +(100--a--b--c)SiO.sub.2 (where M is at least one of Mg, Sr, Ca and Ba; and a, b and c each are, in % by mol, 10.ltoreq.a.ltoreq.60, 5.ltoreq.b.ltoreq.20 and 20.ltoreq.c.ltoreq.35). In producing the capacitor, the laminate of dielectric ceramic layers may be fired in a neutral or reducing atmosphere without being reduced.
    Type: Grant
    Filed: June 4, 1996
    Date of Patent: March 9, 1999
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Toshiki Nishiyama, Yukio Hamaji
  • Patent number: 5853515
    Abstract: A multilayer ceramic capacitor and a process for producing the same, which comprises dielectric ceramic layers, internal electrodes disposed between the dielectric ceramic layers, and an external electrode connected to the internal electrodes, the dielectric ceramic layers comprising barium titanate, a bismuth compound, and an anti-reducing agent, the internal electrodes comprising nickel or a nickel alloy.
    Type: Grant
    Filed: March 26, 1996
    Date of Patent: December 29, 1998
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Harunobu Sano, Yukio Hamaji
  • Patent number: 5841626
    Abstract: A dielectric ceramic composition and a monolithic ceramic capacitor using same are provided. The dielectric ceramic composition includes a main component of barium titanate, scandium oxide, yttrium oxide, manganese oxide and nickel oxide, having the compositional formula:(1-.alpha.-.beta.){BaO}.sub.m.TiO.sub.2 +.alpha.M.sub.2 O.sub.3 +.beta.(Mn.sub.1-x Ni.sub.x)OwhereM.sub.2 O.sub.3 is at least one of Sc.sub.2 O.sub.3 and Y.sub.2 O.sub.3 ; 0.0025.ltoreq..alpha..ltoreq.0.020, 0.0025.ltoreq..beta..ltoreq.0.04, .beta./.alpha..ltoreq.4, 0.ltoreq.x<1.0, 1.000 <m.ltoreq.1.035, andmagnesium oxide in an amount of from about 0.5 to 3.0 mols in terms of MgO, and silicon oxide in an amount of from about 0.2 to 5.0 mols in terms of Si0.sub.2, relative to 100 mols of the main component.
    Type: Grant
    Filed: July 7, 1997
    Date of Patent: November 24, 1998
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Harunobu Sano, Hiroyuki Wada, Yukio Hamaji