Patents by Inventor Nobuyoshi Fujikawa

Nobuyoshi Fujikawa 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: 11887783
    Abstract: A capacitor according to an embodiment of the present disclosure is provided with a capacitor body in which a plurality of dielectric layers and a plurality of internal electrode layers are alternately laminated. The dielectric layers each includes crystal particles, grain boundaries and metal particles. An average particle size of the metal particles is smaller than an average particle size of the crystal particles and larger than an average width of interfacial grain boundaries among the grain boundaries. Observation of the longitudinal cross section of the dielectric layer shows that the metal particles are distributed along the width direction and the thickness direction of the dielectric layer.
    Type: Grant
    Filed: January 17, 2020
    Date of Patent: January 30, 2024
    Assignee: KYOCERA CORPORATION
    Inventors: Maiko Nagayoshi, Nobuyoshi Fujikawa
  • Publication number: 20230187141
    Abstract: A capacitor includes a stack and an external electrode located on a surface of the stack. The stack includes dielectric layers and internal electrode layers alternately stacked on one another. The stack further includes intermediate layers each between a dielectric layer and an internal electrode layer. The intermediate layers contain a dielectric component of the dielectric layers and a conductive component of the internal electrode layers. Each intermediate layer has a concentration gradient in which a concentration of the conductive component decreases from a portion adjacent to the internal electrode layer to a portion adjacent to the dielectric layer.
    Type: Application
    Filed: May 7, 2021
    Publication date: June 15, 2023
    Applicant: KYOCERA Corporation
    Inventors: Nobuyoshi FUJIKAWA, Kiyoshi MATSUBARA
  • Publication number: 20220344099
    Abstract: A capacitor includes a capacitor body including a plurality of dielectric layers and a plurality of internal electrode layers being stacked alternately. The plurality of dielectric layers mainly include crystal grains containing barium titanate as a main component. The plurality of dielectric layers contain magnesium, a rare earth element, and manganese. The plurality of dielectric layers include oxide grains containing at least one of the magnesium, the rare earth element, or the manganese as a single element.
    Type: Application
    Filed: September 10, 2020
    Publication date: October 27, 2022
    Applicant: KYOCERA Corporation
    Inventors: Toshiki OKAZAKI, Nobuyoshi FUJIKAWA
  • Publication number: 20220084749
    Abstract: A capacitor according to an embodiment of the present disclosure is provided with a capacitor body in which a plurality of dielectric layers and a plurality of internal electrode layers are alternately laminated. The dielectric layers each includes crystal particles, grain boundaries and metal particles. An average particle size of the metal particles is smaller than an average particle size of the crystal particles and larger than an average width of interfacial grain boundaries among the grain boundaries. Observation of the longitudinal cross section of the dielectric layer shows that the metal particles are distributed along the width direction and the thickness direction of the dielectric layer.
    Type: Application
    Filed: January 17, 2020
    Publication date: March 17, 2022
    Applicant: KYOCERA Corporation
    Inventors: Maiko NAGAYOSHI, Nobuyoshi FUJIKAWA
  • Patent number: 5650368
    Abstract: A dielectric ceramic composition used for a ceramic capacitor for temperature compensation, a resonator and the like. The dielectric ceramic composition comprises a composite oxide containing, as metal elements, main components of (i) barium, (ii) rare earth elements such as neodymium (Nd) or Nd and Sm in combination, and (iii) elements of the Group IV of periodic table such as titanium (Ti) or Ti and Zr or Sn in combination, and an assistant component of manganese, wherein the main components comprise from 7.5 to 16.25 mol % of a barium oxide, from 16.75 to 23.75 mol % of an oxide of rare earth element, and from 67 to 71.66 mol % of an oxide of element of the Group IV reckoned as a molar composition of the ternary-component-based oxide, the manganese component is contained in an amount of from 0.01 to 0.5% by weight reckoned as MnCO.sub.3 with respect to the main components, and sodium component which is an impurity is contained in an amount of not larger than 0.
    Type: Grant
    Filed: July 26, 1996
    Date of Patent: July 22, 1997
    Assignee: Kyocera Corporation
    Inventors: Yuji Tateishi, Akihiro Kaneuchi, Nobuyoshi Fujikawa
  • Patent number: 5650367
    Abstract: A dielectric ceramic composition containing, per 100 parts by weight of BaTiO.sub.3, at least either one of Nb.sub.2 O.sub.5 or Ta.sub.2 O.sub.5 in an amount of from 0.8 to 3.5 parts by weight, MgO in an amount of from 0.06 to 0.7 parts by weight, oxides of rare earth elements in an amount of from 0.005 to 0.520 parts by weight, and MnO in an amount of from 0.01 to 0.30 parts by weight in the form of MnCO.sub.3, the molar ratio of MgO to either Nb.sub.2 O.sub.5 or Ta.sub.2 O.sub.5 being from 0.5 to 2.2. The dielectric ceramic composition has a dielectric constant of not smaller than 2500, is fired at a temperature of not higher than 1300.degree. C., exhibits a change of capacitance depending upon the temperature satisfying X7R of the IEA Standards, a dielectric loss of not larger than 2.5%, a small voltage dependence, and an insulation resistance of not smaller than 10.sup.4 M.OMEGA., and is suited as a material for producing ceramic capacitors and resonators.
    Type: Grant
    Filed: October 19, 1995
    Date of Patent: July 22, 1997
    Assignee: Kyocera Corporation
    Inventors: Nobuyoshi Fujikawa, Yoshihiro Fujioka, Yasushi Yamakuchi, Shin-ichi Osawa, Hiroshi Ojima
  • Patent number: 5616528
    Abstract: A dielectric ceramic composition comprising main components represented by a composition formula on the weight basis, aMgO.multidot.bCaO.multidot.cTiO.sub.2, wherein a, b and c satisfy the following relationships, 25.ltoreq.a.ltoreq.35, 0.3.ltoreq.b.ltoreq.7, 60.ltoreq.c.ltoreq.70, a+b+c=100, blended with a boron-containing compound in an amount of from 3 to 20 parts by weight reckoned as B.sub.2 O.sub.3 and an alkali metal-containing compound in an amount of from 1 to 12 parts by weight reckoned as the alkali metal carbonate per 100 parts by weight of the main components, as well as a multilayer resonator made of said composition, and a filter using said resonator. The ceramic composition can be fired together with a conductor metal such as Ag or Cu at a relatively low temperature of 900.degree. to 1050.degree. C., exhibits large dielectric constant and Q-value, and a relatively small temperature coefficient .tau.f, lending itself well for use as a material for high-frequency electronic parts.
    Type: Grant
    Filed: November 29, 1995
    Date of Patent: April 1, 1997
    Assignee: Kyocera Corporation
    Inventors: Hirofumi Toda, Shinjiro Shimo, Nobuyoshi Fujikawa, Shinji Isoyama, Kouichi Maruta
  • Patent number: 5504044
    Abstract: A dielectric ceramic composition for high-frequency applications comprising a composite oxide containing at least Ba, Zn and W as metal elements. When the composition formula of the composite oxide is expressed in the form of molar ratios of the metal oxides, the molar ratios of the metal oxides lie within particular ranges. The ceramic composition exhibits a high dielectric constant and a large Q-value in high-frequency regions.
    Type: Grant
    Filed: November 10, 1994
    Date of Patent: April 2, 1996
    Assignee: Kyocera Corporation
    Inventors: Yoshihiro Okawa, Seiichiro Hirahara, Nobuyoshi Fujikawa
  • Patent number: 5432135
    Abstract: A dielectric ceramic composition for high frequency-use comprising a composition (A) containing at least Ba, Mg and W as metal elements represented by a composition formula expressed in a mole ratio of these metal elements, xBaO.yMgO.zWO.sub.3, in which x, y and z satisfy the following relation40.ltoreq.x.ltoreq.60,13.ltoreq.y.ltoreq.40,20.ltoreq.z.ltoreq.30, andx+y+z=100,and at least one element (B) selected from Group 3a elements and Group 4a elements in the periodic table, Sn, Mn and Ca. A ceramic molded product composed of this composition has a high dielectric constant and a high Q value in a high frequency region of at least 10 GHz but also has a temperature coefficient (.tau.f) of a resonance frequency which is not shifted too much to a negative side and has a suitable value. Accordingly, the composition may be preferably used as a resonator and a dielectric substrate material for MIC in a high frequency region of a microwave or a millimeter wave.
    Type: Grant
    Filed: December 16, 1993
    Date of Patent: July 11, 1995
    Assignee: Kyocera Corporation
    Inventors: Seiichi Hirahara, Nobuyoshi Fujikawa, Tsuguo Koyasu, Sumie Koyasu
  • Patent number: 5376603
    Abstract: In a dielectric ceramic composed of a La.sub.2 O.sub.3 -CaO-TiO.sub.2 -MgO type or a BaO-Nd.sub.2 O.sub.3 -TiO.sub.2 type, the oxygen vacancy concentration of the ceramic is controlled below 7.times.10.sup.18 /cm.sup.3 by, for example, annealing the mixture after firing, or heat-treating the mixture after firing. The Q value of the dielectric ceramic can be markedly increased. In addition, ceramics having stable properties can be produced. Thus, the dielectric ceramics can fully cope with high frequencies and large electrification.
    Type: Grant
    Filed: April 28, 1994
    Date of Patent: December 27, 1994
    Assignee: Kyocera Corporation
    Inventors: Seiichiro Hirahara, Nobuyoshi Fujikawa
  • Patent number: 5356844
    Abstract: A dielectric ceramic composition which contains a rare earth element (Ln), Al, Ca and Ti as metal elements and which when these components are expressed in terms of a mole ratio as aLn.sub.2 O.sub.x.bAl.sub.2 O.sub.3. cCaO.dTiO.sub.2, the values of a, b, c, d and x satisfy a+b+c+d=1, 0.056.ltoreq.a.ltoreq.0.214, 0.056.ltoreq.b.ltoreq.0.214, 0.286.ltoreq.c.ltoreq.0.500, 0.230.ltoreq.d.ltoreq.0.470, and 3.ltoreq.x.ltoreq.4. The dielectric having the above composition is disposed between a pair of input and output terminals to constitute a dielectric resonator. The dielectric ceramic composition exhibits such dielectric properties as a large dielectric constant at high frequencies, a large Q-value and a small temperature coefficient of resonance frequency. Satisfactory properties are exhibited when the dielectric ceramic composition is used for a resonator or as a material of circuit board for high-frequency applications.
    Type: Grant
    Filed: June 23, 1993
    Date of Patent: October 18, 1994
    Assignee: Kyocera Corporation
    Inventors: Seiichiro Hirahara, Nobuyoshi Fujikawa, Shinichi Enami, Toyomi Nishi
  • Patent number: 5268341
    Abstract: A dielectric material for high frequency having a composition formula xBaO.yMgO.zWO.sub.3, a composition formula xSrO.yMgO.zWO.sub.3 or a composition formula xBaO.yMgO.zWO.sub.3.wTaO.sub.5/2 wherein x, y, z and w have a specified relationship. It has a high inductivity and a high Q value in a high frequency region especially a microwave and a milliwave.
    Type: Grant
    Filed: October 29, 1992
    Date of Patent: December 7, 1993
    Assignee: Kyocera Corporation
    Inventors: Shigeji Koyasu, Djuniadi A. Sagala, Shinji Nambu, Hidenori Miyata, Seiichiro Hirahara, Nobuyoshi Fujikawa, Gentaro Kaji
  • Patent number: 5198395
    Abstract: A dielectric ceramic composition having a composition (mole %) expressed by the formula xMgO.yLa.sub.2 O.sub.3. xTiO.sub.2 wherein x, y and z are numerals that lie within a range surrounded by a line that couples the points a, b, c, d and e in FIG. 1. The composition can contain 0.01 to 3% by weight of MnO.sub.2 with respect to chief components consisting of the above three components. The composition can be effectively used as a resonator or a circuit board in the microwave frequency region.
    Type: Grant
    Filed: April 26, 1991
    Date of Patent: March 30, 1993
    Assignee: Kyocera Corporation
    Inventors: Hideki Utaki, Toyomi Nishi, Nobuyoshi Fujikawa
  • Patent number: 5065275
    Abstract: A multilayer substrate with inner capacitors comprising a dielectric layer sandwiched between upper and lower insulating layers, a couple of printed electrodes in desired patterns within the thickness of the dielectric layer so as to form each capacitor at the portion of the dielectric layer corresponding to the electrodes, and a couple of leading terminals on one surface of the insulating layer, which communicate with the electrodes, the multilayer substrate being characterized in that the dielectric layer is composed of a ceramic composition mainly comprising MTiO.sub.3 -based ceramics (M represents one or several of Ba, Ca, Mg, La, Sr and Nd) and the insulating layer is composed of a ceramic composition mainly comprising MgO-SiO.sub.2 -CaO-based ceramics, which is defined by an area surrounded by the lines connecting points A, B, C, D, E, F and G as shown in FIG. 1 and listed below, wherein X, Y and Z respectively represent weight percent values of MgO, SiO.sub.2 and CaO at points A, B, C, D, E, F and G.
    Type: Grant
    Filed: September 27, 1990
    Date of Patent: November 12, 1991
    Assignee: Kyocera Corporation
    Inventors: Teruya Fujisaki, Katsuhiko Onitsuka, Yoshihiro Fujioka, Nobuyoshi Fujikawa, Masakazu Yasui, Akira Hashimoto
  • Patent number: 4701827
    Abstract: Disclosed is a multilayer ceramic capacitor comprising internal electrodes composed of nickel and terminations composed of a composition comprising at least one member selected from nickel, cobalt and copper and a zinc borosilicate glass. A zinc borosilicate glass comprising 40 to 65 mole % of ZnO, 20 to 40 mole % of B.sub.2 O.sub.3 and 10 to 35 mole % of SiO.sub.2 is especially suitable as the glass component. The terminations are excellent in adhesion to the internal electrodes and adhesion to a dielectric body.
    Type: Grant
    Filed: February 10, 1986
    Date of Patent: October 20, 1987
    Assignee: Kyocera Corporation
    Inventors: Nobuyoshi Fujikawa, Syuichi Kawaminami, Nobuo Yokoe
  • Patent number: 4628404
    Abstract: A dielectric ceramic composition prepared by adding 0.1 to 1.3% of B.sub.2 O.sub.3, 1.0 to 3.0% of SiO.sub.2 and 0.5 to 3.0% of ZnO to a composition comprising 18.0 to 27.0% of BaTiO.sub.2, 31.6 to 36.3% of Nd.sub.2 O.sub.3, 27.6 to 35.5% of TiO.sub.2, 2.5 to 8.1% of Bi.sub.2 O.sub.3 and 5.6 to 9.0% of Pb.sub.3 O.sub.4, all percentages being by weight. This dielectric composition has a high dielectric constant and a temperature coefficient controlled within a narrow range and can be fired at relatively low temperatures. Because of these properties, it is used as a multilayer ceramic capacitor in combination with an electrode composed of an Ag-Pd alloy containing a major amount of Ag.
    Type: Grant
    Filed: January 9, 1986
    Date of Patent: December 9, 1986
    Assignee: Kyocera Corporation
    Inventors: Nobuo Yokoe, Takashi Okawa, Nobuyoshi Fujikawa, Kazuyoshi Yamashita