Patents by Inventor Akifumi Tosa

Akifumi Tosa 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).

  • Publication number: 20050269287
    Abstract: A multilayer electronic component including a multilayer ceramic capacitor is disclosed, which includes a laminate of dielectric layers and internal electrodes disposed on the dielectric layers; at least one via-conductor penetrating the dielectric layers and connecting to the internal electrodes; and at least one external terminal formed on an outer surface of the laminate and connecting to an end of the via-conductor, wherein the external terminal includes a lower bump formed on the outer surface of the laminate and an upper bump formed on the lower bump, and a diameter of the upper bump is smaller than that of the lower bump.
    Type: Application
    Filed: June 6, 2005
    Publication date: December 8, 2005
    Inventors: Yasuhiro Tsujimura, Akifumi Tosa, Motonobu Kurahashi, Manabu Sato
  • Publication number: 20050122662
    Abstract: A laminated ceramic capacitor 10 divided into a first laminate 11, a second laminate 12, a third laminate 13, and a fourth laminate 14. The first laminate 11 includes a ceramic layer 15 serving as a dielectric layer. The ceramic layer 15 is thicker than a ceramic layer 17 sandwiched between internal electrodes 16a in the second laminate 12 or the fourth laminate 14, and thinner than 20 times the thickness of the ceramic layer 17. The third laminate 13 includes dielectric layers, which serve as the ceramic layers 17, and has a thickness of 5% of the total thickness of the second laminate 12 and the fourth laminate 14. Accordingly, the third laminate 13 achieves the function of absorbing an electrode-induced thickness differential. Also, by means of regulating the thickness of the first laminate 11, portions of via electrodes 18 that extend without being electrically connected to the internal electrodes 16b can be shortened.
    Type: Application
    Filed: December 6, 2004
    Publication date: June 9, 2005
    Inventors: Kazuhiro Hayashi, Akifumi Tosa, Motohiko Sato, Jun Otsuka, Manabu Sato
  • Publication number: 20050051253
    Abstract: A method for producing a ceramic substrate which employs a cofiring process using restraint sheets in which a second ceramic green sheet 7 is laminated on a green ceramic substrate 30 so as to cover surface conductors 32 of the green ceramic substrate 30, the second ceramic green sheet 7 subsequently being integrated with the green ceramic substrate 30. Restraint sheets 9, which are not sintered at a sintering temperature at which the green ceramic substrate 30 is sintered, are laminated on corresponding opposite sides of the green ceramic substrate 30 so as to restrain the green ceramic substrate 30 together with the second ceramic green sheet 7. The second ceramic green sheet 7 and the green ceramic substrate 30 are fired at a temperature at which the second ceramic green sheet 7 and the green ceramic substrate 30 are integrally sintered, whereas the restraint sheets 9 are not sintered, to thereby yield a ceramic substrate 40.
    Type: Application
    Filed: September 8, 2004
    Publication date: March 10, 2005
    Inventors: Akifumi Tosa, Jun Otsuka, Manabu Sato, Hisahito Kashima
  • Patent number: 6844284
    Abstract: A dielectric porcelain composition comprising Ba, Nd, Pr, Bi, Ti and at least one of Na and K and satisfying a condition that when the composition is expressed by composition formula: BaO—aNdO3/2—bPrO11/6—cBiO3/2—dTiO2—eAO1/2, wherein A is at least one of Na and K, and a, b, c, d and e represent a molar ratio, a, b, c, d and e are in respective ranges of 1.5?a?2.6, 0.02?b?1.00, 0.2?c?0.6, 4.5?d?5.5 and 0.02?e?0.30.
    Type: Grant
    Filed: November 12, 2002
    Date of Patent: January 18, 2005
    Assignee: NGK Spark Plug Co., Ltd.
    Inventors: Akifumi Tosa, Jun Otsuka, Manabu Sato
  • Publication number: 20030119657
    Abstract: A dielectric porcelain composition comprising Ba, Nd, Pr, Bi, Ti and at least one of Na and K and satisfying a condition that when the composition is expressed by composition formula: BaO-aNdO3/2-bPrO11/6-cBiO3/2-dTiO2-eAO1/2, wherein A is at least one of Na and K, and a, b, c, d and e represent a molar ratio, a, b, c, d and e are in respective ranges of 1.5≦a≦2.6, 0.02≦b≦1.00, 0.2≦c≦0.6, 4.5≦d≦5.5 and 0.02≦e≦0.30.
    Type: Application
    Filed: November 12, 2002
    Publication date: June 26, 2003
    Applicant: NGK SPARK PLUG CO., LTD.
    Inventors: Akifumi Tosa, Jun Otsuka, Manabu Sato
  • Publication number: 20030109374
    Abstract: A dielectric ceramic material is represented by the following compositional formula, (100-a)[Bau{(ZnvCo1-v)wNbx}O&dgr;1]-a[MyTa2O&dgr;2], where M represents at least one species selected from K, Na, and Li. In one method, the dielectric material is produced by mixing raw material powders such that proportions by mol of component metals simultaneously satisfy the relations, 0.5≦a≦25; 0.98≦u 23 1.03; 0≦v≦1; 0.274 ≦w≦0.374; 0.646≦x ≦0.696; 0.5≦y≦2.5; and 0.8≦z≦1.2. The method further includes subjecting the resultant mixture to primary pulverization; calcining the resultant powder at 1,100-1,300° C., followed by wet secondary pulverization; drying the resultant paste; granulating; molding the resultant granules to thereby yield a compact; and firing the compact in air advantageously at 1,400-1,600° C.
    Type: Application
    Filed: July 15, 2002
    Publication date: June 12, 2003
    Inventors: Takashi Oba, Masahiko Matsumiya, Akifumi Tosa, Kazuhisa Itakura
  • Patent number: 6569796
    Abstract: The present invention is directed to a dielectric ceramic composition exhibiting a high unloaded quality factor and a small variation thereof. The dielectric ceramic composition of the invention containing Ba, Zn, and Ta, contains 100 parts by weight of a predominant component represented by xBaO—yZnO—(½)zTa2O5 (x, y, and z represent compositional proportions by mol and satisfy x+y+z=1), wherein x, y, and z fall within a quadrilateral region formed by connecting points A (x=0.503, y=0.152, z=0.345), B (x=0.497, y=0.158, z=0.345), C (x=0.503, y=0.162, z=0.335), and D (x=0.497, y=0.168, z=0.335) (sides AB, BD, DC, and CA being included) as shown in FIG. 1; 0.2-1.6 parts by weight K as reduced to K2O; and 0.7-8 parts by weight Ta as reduced to Ta2O5, wherein the ratio by weight of K to Ta falls within the range of 0.185-0.4.
    Type: Grant
    Filed: January 7, 2002
    Date of Patent: May 27, 2003
    Assignee: NGK Spark Plug Co., Ltd.
    Inventors: Kazuhisa Itakura, Takashi Oba, Akifumi Tosa, Kazushige Obayashi
  • Publication number: 20030050179
    Abstract: The present invention is directed to a dielectric ceramic composition exhibiting a high unloaded quality factor and a small variation thereof. The dielectric ceramic composition of the invention containing Ba, Zn, and Ta, contains 100 parts by weight of a predominant component represented by xBaO-yZnO-(½)zTa2O5 (x, y, and z represent compositional proportions by mol and satisfy x+y+z=1), wherein x, y, and z fall within a quadrilateral region formed by connecting points A (x=0.503, y=0.152, z=0.345), B (x=0.497, y=0.158, z=0.345), C (x=0.503, y=0.162, z=0.335), and D (x=0.497, y=0.168, z=0.335) (sides AB, BD, DC, and CA being included) as shown in FIG. 1; 0.2-1.6 parts by weight K as reduced to K2O; and 0.7-8 parts by weight Ta as reduced to Ta2O5, wherein the ratio by weight of K to Ta falls within the range of 0.185-0.4.
    Type: Application
    Filed: January 7, 2002
    Publication date: March 13, 2003
    Inventors: Kazuhisa Itakura, Takashi Oba, Akifumi Tosa, Kazushige Obayashi
  • Patent number: 6117806
    Abstract: Dielectric materials are disclosed that are based on BaO--ZnO--Ta.sub.2 O.sub.5 represented by the formula Ba(Zn.sub.1/3 Ta.sub.2/3)O.sub.3. Ba has been partly replaced by K and either Zn or Ta has been replaced by at least one element selected from Mg, Zr, Ga, Ni, Nb, Sn. The dielectric materials have a relatively high permittivity, a small absolute value of the temperature coefficient of resonance frequency, and a high unloaded quality factor. A method for producing the dielectric materials is also disclosed which includes mixing given amounts of starting materials, such as, for example, BaCO.sub.3, ZnO, Ta.sub.2 O.sub.5, K.sub.2 CO.sub.3, MgCO.sub.3, SnO.sub.2 or ZrO.sub.2, compacting the mixture to produce a compact, sintering the compact in an oxidizing atmosphere such as, for example, air, at 1,400 and 1,600.degree. C., more preferably at 1,550 to 1,600.degree. C. for 2 hours, and then heating the sintered compact at a temperature lower than the sintering temperature by from 50 to 250.degree. C., e.g.
    Type: Grant
    Filed: October 24, 1997
    Date of Patent: September 12, 2000
    Assignee: NGK Spark Plug Co., Ltd.
    Inventors: Hitoshi Yokoi, Akifumi Tosa, Kazushige Ohbayashi