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).
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Patent number: 11887783Abstract: 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: GrantFiled: January 17, 2020Date of Patent: January 30, 2024Assignee: KYOCERA CORPORATIONInventors: Maiko Nagayoshi, Nobuyoshi Fujikawa
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Publication number: 20230187141Abstract: 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: ApplicationFiled: May 7, 2021Publication date: June 15, 2023Applicant: KYOCERA CorporationInventors: Nobuyoshi FUJIKAWA, Kiyoshi MATSUBARA
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Publication number: 20220344099Abstract: 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: ApplicationFiled: September 10, 2020Publication date: October 27, 2022Applicant: KYOCERA CorporationInventors: Toshiki OKAZAKI, Nobuyoshi FUJIKAWA
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Publication number: 20220084749Abstract: 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: ApplicationFiled: January 17, 2020Publication date: March 17, 2022Applicant: KYOCERA CorporationInventors: Maiko NAGAYOSHI, Nobuyoshi FUJIKAWA
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Patent number: 5650368Abstract: 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: GrantFiled: July 26, 1996Date of Patent: July 22, 1997Assignee: Kyocera CorporationInventors: Yuji Tateishi, Akihiro Kaneuchi, Nobuyoshi Fujikawa
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Patent number: 5650367Abstract: 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: GrantFiled: October 19, 1995Date of Patent: July 22, 1997Assignee: Kyocera CorporationInventors: Nobuyoshi Fujikawa, Yoshihiro Fujioka, Yasushi Yamakuchi, Shin-ichi Osawa, Hiroshi Ojima
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Patent number: 5616528Abstract: 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: GrantFiled: November 29, 1995Date of Patent: April 1, 1997Assignee: Kyocera CorporationInventors: Hirofumi Toda, Shinjiro Shimo, Nobuyoshi Fujikawa, Shinji Isoyama, Kouichi Maruta
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Patent number: 5504044Abstract: 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: GrantFiled: November 10, 1994Date of Patent: April 2, 1996Assignee: Kyocera CorporationInventors: Yoshihiro Okawa, Seiichiro Hirahara, Nobuyoshi Fujikawa
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Patent number: 5432135Abstract: 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: GrantFiled: December 16, 1993Date of Patent: July 11, 1995Assignee: Kyocera CorporationInventors: Seiichi Hirahara, Nobuyoshi Fujikawa, Tsuguo Koyasu, Sumie Koyasu
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Patent number: 5376603Abstract: 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: GrantFiled: April 28, 1994Date of Patent: December 27, 1994Assignee: Kyocera CorporationInventors: Seiichiro Hirahara, Nobuyoshi Fujikawa
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Patent number: 5356844Abstract: 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: GrantFiled: June 23, 1993Date of Patent: October 18, 1994Assignee: Kyocera CorporationInventors: Seiichiro Hirahara, Nobuyoshi Fujikawa, Shinichi Enami, Toyomi Nishi
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Patent number: 5268341Abstract: 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: GrantFiled: October 29, 1992Date of Patent: December 7, 1993Assignee: Kyocera CorporationInventors: Shigeji Koyasu, Djuniadi A. Sagala, Shinji Nambu, Hidenori Miyata, Seiichiro Hirahara, Nobuyoshi Fujikawa, Gentaro Kaji
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Patent number: 5198395Abstract: 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: GrantFiled: April 26, 1991Date of Patent: March 30, 1993Assignee: Kyocera CorporationInventors: Hideki Utaki, Toyomi Nishi, Nobuyoshi Fujikawa
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Patent number: 5065275Abstract: 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: GrantFiled: September 27, 1990Date of Patent: November 12, 1991Assignee: Kyocera CorporationInventors: Teruya Fujisaki, Katsuhiko Onitsuka, Yoshihiro Fujioka, Nobuyoshi Fujikawa, Masakazu Yasui, Akira Hashimoto
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Patent number: 4701827Abstract: 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: GrantFiled: February 10, 1986Date of Patent: October 20, 1987Assignee: Kyocera CorporationInventors: Nobuyoshi Fujikawa, Syuichi Kawaminami, Nobuo Yokoe
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Patent number: 4628404Abstract: 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: GrantFiled: January 9, 1986Date of Patent: December 9, 1986Assignee: Kyocera CorporationInventors: Nobuo Yokoe, Takashi Okawa, Nobuyoshi Fujikawa, Kazuyoshi Yamashita