Patents by Inventor Eiichi Asada

Eiichi Asada 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: 6060165
    Abstract: A metal powder having a vitreous thin layer on at least a part of the surface thereof wherein the amount of the vitreous thin layer is preferably 0.01 to 50% by weight based on the metal powder without the vitreous thin layer. The metal powder is prepared by a process comprising the steps of: bringing a solution comprising a heat-decomposable metal compound to fine droplets; and heating the droplets to a temperature above the decomposition temperature of the metal compound, wherein a precursor of an oxide, heat-decomposable to produce a vitreous material which, together with the metal, does not form a solid solution, is added to the solution and the vitreous material is deposited, upon the heating, in the vicinity of the surface of the metal powder. The powder is useful for the preparation of a thick film paste used in a multilayer ceramic electronic component or substrate, since it has an excellent oxidation resistance during storage, in a conductor paste, and during firing of the paste.
    Type: Grant
    Filed: September 23, 1997
    Date of Patent: May 9, 2000
    Assignee: Shoei Chemical Inc.
    Inventors: Eiichi Asada, Yuji Akimoto, Fumiyuki Shimizu, Kazuro Nagashima
  • Patent number: 6007743
    Abstract: A nickel powder having at at least part of the surface thereof a layer of a composite oxide represented by the formula: A.sub.x B.sub.y O.sub.(x+2y), wherein A stands for at least one element selected from the group consisting of Ca, Sr and Ba; B stands for at least one element selected from the group consisting of Ti and Zr; and x and y represent numbers satisfying the formula: 0.5.ltoreq.y/x.ltoreq.4.5). The nickel powder may further contains at least one selected from among boron oxide, aluminum oxide and silicon oxide. The nickel powder is produced by spray pyrolyzing a solution of thermal decomposable starting compounds of nickel and additive elements and the resultant powder is suitable for use in a thick-film conductor paste having a sintering-starting temperature close to that of ceramic layers and a shrinkage behavior close to that of a ceramic without detriment to the conductivity and electric properties thereof.
    Type: Grant
    Filed: February 17, 1998
    Date of Patent: December 28, 1999
    Assignee: Shoei Chemical, Inc.
    Inventors: Eiichi Asada, Yuji Akimoto, Kazuro Nagashima, Hiroshi Yoshida, Yiyi Ma
  • Patent number: 5964918
    Abstract: A process for preparing a metal powder, comprising the steps of: bringing a solution comprising at least one metal salt to fine droplets; and heating the droplets to a temperature above the decomposition temperature of the metal salt, wherein at least one compound which is heat-decomposable to produce a metal, a semimetal or an oxide of the metal or semimetal capable of remaining unmelted upon heating at the heat temperature is added to the solution and at least one selected from the group consisting of the metal, semimetal and oxide is heat-segregated in the vicinity of the surface of the metal powder. The resultant metal powder has a uniform particle size and good dispersibility without fusing or aggregation and is useful for the preparation of thick film pastes used in electronic circuits or components.
    Type: Grant
    Filed: September 23, 1997
    Date of Patent: October 12, 1999
    Assignee: Shoei Chemical Inc.
    Inventors: Eiichi Asada, Yuji Akimoto, Kazuro Nagashima, Mineto Iwasaki
  • Patent number: 5871840
    Abstract: A nickel powder having a composite oxide layer comprising lanthanum and nickel and, optionally an oxide of chromium, on at least a part of the surface thereof. The nickel powder is produced by a process comprising the steps of: bringing a solution comprising at least one heat-decomposable nickel compound and at least one heat-decomposable lanthanum compound and, optionally, at least one heat-decomposable chromium compound, to fine droplets; and heating the droplets at a temperature above the decomposition temperatures of these compounds to prepare a nickel powder and, at the same time, to deposit a composite oxide layer comprising lanthanum and nickel and, when present, chromium oxide, in the vicinity of the surface of the nickel powder.
    Type: Grant
    Filed: September 23, 1997
    Date of Patent: February 16, 1999
    Assignee: Shoei Chemical Inc.
    Inventors: Eiichi Asada, Yuji Akimoto, Kazuro Nagashima
  • Patent number: 5763339
    Abstract: A lead-free insulating glass composition comprises (A) 50 to 85 wt. % of a glass comprising, on a weight basis, 28 to 38% of SiO.sub.2, 4 to 10% of B.sub.2 O.sub.3, 8 to 16% of Al.sub.2 O.sub.3, 15 to 23% of MgO, 1 to 12% of CaO, 3 to 9% of BaO, 8 to 16% of ZnO, and 3 to 8% of ZrO.sub.2 ; and (B) 50 to 15 wt. % of at least one filler selected from the group consisting of alumina and zircon. When using this glass composition as an insulating layer of a thick-film multilayer circuit board, there can be obtained a highly reliable thick-film multilayer circuit board in which the warpage of the substrate and leakage current are greatly reduced and the withstand voltage is highly improved.
    Type: Grant
    Filed: January 10, 1997
    Date of Patent: June 9, 1998
    Assignee: Shoei Chemical Inc.
    Inventors: Eiichi Asada, Tetsuya Tanaka
  • Patent number: 5645765
    Abstract: A nontoxic lead-free conductive paste comprising (a) a lead-free glass frit having a crystallization temperature of 700.degree.-870.degree. C. and consisting essentially of, by weight %, 20-38% of SiO.sub.2, 5.5-13.5% of B.sub.2 O.sub.3, 8-15.5% of Al.sub.2 O.sub.3, 4-19% of CaO, 20-29% of ZnO, 0-6% of ZrO.sub.2, 4-16% of TiO.sub.2 and 0.1-3.8% of MoO.sub.3 ; (b) finely divided particles of electrically conductive material; (c) at least one inorganic additive selected from the group consisting of bismuth oxide, zinc oxide-containing containing oxide material, manganese oxide, copper oxide and molybdenum oxide; and (d) an organic medium. The nontoxic conductive paste is free from environmental and health problems and results in conductors having excellent solderability, solder leach resistance, adhesion strength and electrical properties, both on ceramic substrates such as alumina or on dielectric bodies.
    Type: Grant
    Filed: May 22, 1996
    Date of Patent: July 8, 1997
    Assignee: Shoei Chemical Inc.
    Inventors: Eiichi Asada, Tetsuya Tanaka
  • Patent number: 5420744
    Abstract: A multilayered ceramic capacitor having internal electrodes comprising a substantially single-crystal metallic powder as a conductor, the powder having been produced by spraying a solution containing at least one metal salt to form droplets and heating the droplets to a temperature higher than the decomposition temperature of the metal salt and the melting point of the metal. When the metal salt forms an oxide at a temperature not higher than the melting point of the metal, the droplets are heated to a temperature higher than the decomposition temperature of the oxide. The multilayered capacitor is free from generated cracks in the ceramic material.
    Type: Grant
    Filed: September 21, 1993
    Date of Patent: May 30, 1995
    Assignee: Shoei Chemical Inc.
    Inventors: Eiichi Asada, Kazurou Nagashima
  • Patent number: 5402305
    Abstract: An oxidation-resistant palladium powder containing one or more alkaline earth metal elements in a total amount of at least 0.005% by weight relative to Pd. The palladium powder is useful as a conductive component of a thick-film conductive paste and the resultant conductive paste can provide internal electrodes to a multilayered ceramic capacitor with minimized structural defects such as cracks or delamination. The palladium powder is produced by spraying a palladium salt solution containing one or more alkaline earth metal elements to form droplets and heating the droplets to a temperature of at least 1000.degree. C. The preferred amount of the alkaline earth metal elements in the Pd powder is from 0.005 to 0.1% by weight relative to Pd and the preferred alkaline earth metal elements are one or more elements selected from the group consisting of Mg, Ca, Sr and Ba.
    Type: Grant
    Filed: November 29, 1993
    Date of Patent: March 28, 1995
    Assignee: Shoei Chemical Inc.
    Inventors: Eiichi Asada, Yuji Akimoto, Shinichi Ono, Kazurou Nagashima, Mineto Iwasaki, Masayuki Maekawa
  • Patent number: 4986933
    Abstract: A resistor composition comprising at least one electrically conductive powder selected from the group consisting of (a) tin oxide power and (b) powder resulting from heat treatment of tin oxide and tantalum oxide, a glass frit and double oxide of tantalum dispersed in an organic vehicle. In the resistor composition, the mixing amount of the double oxide of tantalum is preferably 30 parts by weight or less with respect to 100 parts by weight of the sum of the electrically conductive powder and the glass frit. The resistor composition provides highly reproducible thick film resistors having superior properties and high stability over a wide range of resistance by addition of the tantalum double oxides.
    Type: Grant
    Filed: March 21, 1990
    Date of Patent: January 22, 1991
    Assignee: Shoei Chemical Inc.
    Inventors: Eiichi Asada, Mikio Yamazoe, Shigeru Matsumura
  • Patent number: 4752442
    Abstract: A bonding wire for use in semiconductor devices which consists essentially of 0.0003 to 0.01 wt. % of barium and the balance gold, the gold purity of said bonding wire being at least 99.99%. The bonding wire may further contain at least one element selected from the group consisting of 0.0005 to 0.005 wt. % of aluminum, 0.0001 to 0.003 wt. % of calcium, 0.0005 to 0.005 wt. % of silver and 0.0005 to 0.005 wt. % of palladium. The total content of the elements and barium in the bonding wire should not exceed 0.01 wt. % based on the weight of the bonding wire so that the gold purity of the bonding wire is at least 99.99%. The use of the additive elements improve the mechanical strength and wire-bondability, making the bonding wire highly suitable for use in wire bonding of semiconductor elements, especially for high-speed bonding.
    Type: Grant
    Filed: July 16, 1987
    Date of Patent: June 21, 1988
    Assignee: Shoei Chemical Inc.
    Inventors: Eiichi Asada, Kazuo Yokoyama, Masahiro Yata, Kenichi Hirano
  • Patent number: 4574055
    Abstract: A resistor composition comprising conductive particles, a glass frit and a vehicle in which RuO.sub.2 particles coated with a polynary oxide of Bi and/or Pb and Ru are employed and, by using the surface-coated RuO.sub.2, the composition can provide readily a improved resistor having a advantageous combination of properties, particularly a very small absolute TCR and high voltage stability throughout a wide resistance range. The produced resistor can be successfully laser-trimmed without adversely affecting the properties thereof.
    Type: Grant
    Filed: December 12, 1984
    Date of Patent: March 4, 1986
    Assignee: Shoei Chemical Inc.
    Inventors: Eiichi Asada, Toshio Inokuma, Mikio Yamazoe
  • Patent number: 4439352
    Abstract: Resistor compositions are disclosed which comprise: (a) ruthenium oxide; (b) glass; (c) at least one metal oxide selected from the group consisting of lanthanum oxide, neodymium oxide, praseodymium oxide and samarium oxide; and (d) an organic vehicle. Resistors are produced using this composition by firing a resistor film comprising ruthenium oxide, glass and at least one metal oxide selected from the group consisting of lanthanum oxide, neodymium oxide, praseodymium oxide and samarium oxide onto an electrically insulating substrate. The use of the metal oxides in the resistor compositions surprisingly improve the TCR (temperature coefficient of resistance) particularly in high resistance ranges, and brings the TCR close to zero. In addition to the effect of improving the TCR, the metal oxides increase resistance and improve noise and VCR (voltage coefficient of resistance) properties.
    Type: Grant
    Filed: December 1, 1982
    Date of Patent: March 27, 1984
    Assignee: Shoei Chemical Inc.
    Inventors: Eiichi Asada, Toshio Inokuma, Hiroyuku Saito
  • Patent number: 4293839
    Abstract: A thick film resistor comprising a resistive film element comprising 100 parts by weight of RuO.sub.2 and glass and 0.1 to 15 parts by weight of Au, electrodes containing not less than 50 weight percent of Ag therein connected to the terminal portions of the resistive film element, and an insulating substrate on which the resistive film element and the electrodes are formed.
    Type: Grant
    Filed: March 12, 1980
    Date of Patent: October 6, 1981
    Assignee: Shoei Chemical Incorporated
    Inventors: Eiichi Asada, Toshio Inokuma, Isao Egawa
  • Patent number: 4080210
    Abstract: A method and apparatus for preparing uniformly-sized particles wherein a first liquid reactant is chemically reacted with a second liquid reactant to form precipitated particles of substantially uniform particle size which comprises forming substantially uniformly-sized droplets of one of said reactants and directing said droplets against the falling flow of the other of said reactants.
    Type: Grant
    Filed: December 8, 1975
    Date of Patent: March 21, 1978
    Assignee: Shoei Chemical Incorporated
    Inventors: Eiichi Asada, Hiromu Sasaki, Toshio Matsuhashi
  • Patent number: 4051074
    Abstract: A resistor composition and process for making the same which comprises a conductive material, a glass frit and a vehicle therefor or a conductive material, a glass frit, an insulating or semiconductive metal oxide and a vehicle therefor, the weight ratio of said conductive material, said glass frit and said metal oxide, when the latter is present, being maintained substantially constant, wherein the resistance value of said composition is established by varying the total surface area of said conductive material, and said glass frit and, when applicable, said metal oxide, without changing the temperature coefficient of resistance of said composition.
    Type: Grant
    Filed: October 29, 1975
    Date of Patent: September 27, 1977
    Assignee: Shoei Kagaku Kogyo Kabushiki Kaisha
    Inventor: Eiichi Asada