Patents by Inventor Takashi Fukaumi

Takashi Fukaumi 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: 6352564
    Abstract: The present invention provides an electrically conductive polymer layer of a solid electrolytic capacitor, the electrically conductive polymer layer coating a dielectric layer coating an anode with an anode lead which projects outwardly from the anode through the dielectric layer, and the electrically conductive polymer layer being separated by the dielectric layer from the anode lead, wherein the electrically conductive polymer layer has a thicker portion than a remaining portion thereof and the thicker portion extends at least in the vicinity of the anode lead, and the thicker portion is bounded with the remaining portion so that a sloped-boundary loop between the thicker portion and the remaining portion extends to be parallel to a flat plane vertical to a direction along which the anode lead projects through the dielectric layer, whereby the thicker portion continuously extends in a closer side to the anode lead than the remaining portion.
    Type: Grant
    Filed: September 8, 2000
    Date of Patent: March 5, 2002
    Assignee: NEC Corporation
    Inventors: Kenji Araki, Takashi Fukaumi, Yuji Aoki, Kenichi Takahashi
  • Patent number: 6229689
    Abstract: A solid electrolyte capacitor having a solid electrolyte layer that is formed of a polymeric product layer of a polymerizable monomer. The polymeric product layer is doped with an organic sulfonic acid selected from the group consisting of an aromatic polysulfonic acid, an organic sulfonic acid having a hydroxy group, an organic sulfonic acid having a carboxyl group, an alicyclic sulfonic acid, and a benzoquinone sulfonic acid.
    Type: Grant
    Filed: July 16, 1997
    Date of Patent: May 8, 2001
    Assignee: NEC Corporation
    Inventors: Atsushi Kobayashi, Takashi Fukaumi, Tomohide Date
  • Patent number: 6219223
    Abstract: In a solid electrolyte capacitor including a solid electrolyte implemented by a conducting polymer produced by the chemical oxidative polymerization of a polymerization system containing a monomer, a cation serving as an oxidizer, and an anion serving as a dopant, the polymerization system contains the anion in a stoichiometrically excessive amount relative to the cation. The conductivity of a conducting polymer included in the capacitor is prevented from being deteriorated in a high temperature atmosphere, so that a desirable ESR is preserved during 125° C. heat test. In addition, a conductive high polymer layer having an extremely desirable film property is formed. This successfully prevents stresses ascribable to the expansion and contraction of a seal resin from being transferred to the capacitor during heat test, and thereby protects LC and ESR from deterioration.
    Type: Grant
    Filed: September 24, 1998
    Date of Patent: April 17, 2001
    Assignee: NEC Corporation
    Inventors: Atsushi Kobayashi, Kenji Araki, Takashi Fukaumi
  • Patent number: 6215651
    Abstract: A multilayer structure in a solid electrolyte capacitor. The multilayer structure extends over a pore and a peripheral surface in the vicinity of the pore in a porous surface. The multilayer structure includes a dielectric layer having a first part extending on an inner surface of the pore and a second part extending on an outer surface of the peripheral surface; a first coupling layer extending on the first part of the dielectric layer; a first conductive polymer layer extending on the first coupling layer; a second coupling layer extending on at least the second part of the dielectric layer; and a second conductive polymer layer extending on the second coupling layer so that the second conductive polymer layer extends at least over the peripheral surface.
    Type: Grant
    Filed: February 2, 1999
    Date of Patent: April 10, 2001
    Assignee: NEC Corporation
    Inventors: Daisuke Takada, Takashi Fukaumi, Kenji Araki, Yuji Aoki, Kenichi Takahashi
  • Patent number: 6212064
    Abstract: The object of the present invention is to provide a solid electrolytic capacitor which can prevent an oxidation degradation of a solid electrolyte caused by heat stress and the like during packaging, which has low an ESR, and a production method of the same; in order to achieve this object, the solid electrolytic capacitor of the present invention includes in order an anode, a dielectric coat, a solid electrolyte layer, and a conductive paste layer, with a conductive polymer is used as the solid electrolyte, wherein the conductive paste layer contains acrylic resins and cellulose resins as a binder, and the thickness of the conductive paste layer is in a range of 20 to 40 &mgr;m.
    Type: Grant
    Filed: April 8, 1999
    Date of Patent: April 3, 2001
    Assignee: NEC Corporation
    Inventors: Yuji Aoki, Kennji Araki, Takashi Fukaumi, Kennichi Takahashi, Daisuke Takada
  • Patent number: 6210450
    Abstract: In a method of making a solid electrolytic capacitor using an oxide film of an electrochemical valve metal as the dielectric and having, as solid electrolytes, first and second conducting polymer layers formed successively on the oxide film, the first and second conducting polymer layers are formed by chemical oxidative polymerization processes using an oxidizing agent, and the first conducting polymer layer (3) is formed from a compound having a lower reaction rate than the compound used to form the second conducting polymer layer (4). According to this method, there can be obtained solid electrolytic capacitors having high heat resistance and showing an improvement in capacitance appearance factor and frequency characteristics.
    Type: Grant
    Filed: July 26, 2000
    Date of Patent: April 3, 2001
    Assignee: NEC Corporation
    Inventors: Takashi Fukaumi, Kenji Araki, Satoshi Arai, Yuji Aoki, Kenichi Takahashi
  • Patent number: 6154358
    Abstract: In a method of making a solid electrolytic capacitor using an oxide film of an electrochemical valve metal as the dielectric and having, as solid electrolytes, first and second conducting polymer layers formed successively on the oxide film, the first and second conducting polymer layers are formed by chemical oxidative polymerization processes using an oxidizing agent, and the first conducting polymer layer (3) is formed from a compound having a lower reaction rate than the compound used to form the second conducting polymer layer (4).
    Type: Grant
    Filed: July 23, 1998
    Date of Patent: November 28, 2000
    Assignee: NEC Corporation
    Inventors: Takashi Fukaumi, Kenji Araki, Satoshi Arai, Yuji Aoki, Kenichi Takahashi
  • Patent number: 6151205
    Abstract: A solid electrolytic capacitor using a conducting polymer to be formed by chemical oxidative polymerization as a solid electrolyte, the capacitor having: a capacitor element which includes a conducting polymer layer with a thickness of 0.02 .mu.m or greater at its central part. A method for making the solid electrolytic capacitor, having the steps of: providing at least two kinds of solutions with different oxidizing-agent concentrations; and adjusting the thickness of a conducting polymer layer at central part of a capacitor element to be 0.02 .mu.m or greater by using first a solution with a lowest oxidizing-agent concentration of the solutions and subsequently a solution with a next lowest oxidizing-agent concentration of the solutions.
    Type: Grant
    Filed: September 9, 1998
    Date of Patent: November 21, 2000
    Assignee: NEC Corporation
    Inventors: Atsushi Kobayashi, Kenji Araki, Takashi Fukaumi
  • Patent number: 6128180
    Abstract: An electrically conductive polymer layer of a solid electrolytic capacitor that coats a dielectric layer that coats an anode. An anode lead projects outwardly from the anode through the dielectric layer, and the electrically conductive polymer layer is separated by the dielectric layer form the anode lead. The electrically conductive polymer layer has a thicker portion than a remaining portion thereof and the thicker portion extends at least in the vicinity of the anode lead, and the thicker portion is bounded with the remaining portion so that a sloped-boundary loop between the thicker portion and the remaining portion extends to be parallel to a flat plane perpendicular to a direction along which the anode lead projects through the dielectric layer, whereby the thicker portion continuously extends close to the anode lead than the remaining portion.
    Type: Grant
    Filed: December 4, 1998
    Date of Patent: October 3, 2000
    Assignee: NEC Corporation
    Inventors: Kenji Araki, Takashi Fukaumi, Yuji Aoki, Kenichi Takahashi
  • Patent number: 6110235
    Abstract: A fabrication method of a solid electrolytic capacitor is provided, which decreases the leakage current of a solid electrolytic capacitor without deterioration of ESR. This method is comprised of the steps (a) to (e). In the step (a), a capacitor body is formed by a valve metal, the body serving as an anode of the capacitor. In the step (b), an oxide layer of the valve metal is formed to cover a surface of the capacitor body by anodic oxidation, the oxide layer serving as a dielectric of the capacitor. In the step (c), a layer of an organic conducting polymer is formed on the oxide layer, the layer of the organic conducting polymer serving as a solid electrolyte of the capacitor. In the step (d), the capacitor body with the oxide layer and the layer of the organic conducting polymer is immersed in a reoxidation solution, the reoxidation solution containing a mixture of water and alcohol or a mixture of water and ketone as a solvent.
    Type: Grant
    Filed: August 31, 1998
    Date of Patent: August 29, 2000
    Assignee: NEC Corporation
    Inventors: Kenji Araki, Satoshi Arai, Yuuji Aoki, Kenichi Takahashi, Takashi Fukaumi
  • Patent number: 6110234
    Abstract: In a method of manufacturing a solid electrolytic capacitor, an oxide film as a dielectric layer is formed on a surface of a sintered body formed from a valve action metal and having an anode lead. A solid electrolytic layer essentially consisting of a conductive polymer is formed on the dielectric layer. In the step of forming the solid electrolytic layer, the sintered body having the dielectric layer is dipped in an oxidant solution, and the oxidant solution on the surface of the extracted sintered body is evaporated. Then, the sintered body is dipped in a monomer solution prepared by dissolving a conductive polymeric monomer in a solution in which the oxidant is not dissolved, and the monomer solution on the surface of the extracted sintered body is evaporated to form the conductive polymer layer.
    Type: Grant
    Filed: July 23, 1998
    Date of Patent: August 29, 2000
    Assignee: NEC Corporation
    Inventors: Koji Sakata, Toshihiko Nishiyama, Takashi Fukaumi, Satoshi Arai
  • Patent number: 6086642
    Abstract: A fabrication method of a solid electrolytic capacitor is provided, which decreases the necessary repetition number of adhesion steps of an oxidizing agent and a monomer of a conducting polymer to a dielectric of the capacitor while keeping the coverage ratio at a satisfactorily high level. A capacitor body with an oxide layer is first immersed into an oxidizer solution at a room temperature under an atmospheric pressure. The oxidizer solution has a viscosity ranging from 100 to 500 cp at room temperature under the atmospheric pressure. Then, the oxidizer solution adhered to the oxide layer is dried to remove a solvent of the adhered solution and to leave the oxidizing agent on the oxide layer. The oxidizing agent left on the oxide layer is in solid phase at room temperature under the atmospheric pressure. The capacitor body with the oxide layer is immersed into a monomer of a conducting polymer.
    Type: Grant
    Filed: November 20, 1997
    Date of Patent: July 11, 2000
    Assignee: NEC Corporation
    Inventors: Takashi Fukaumi, Tomohide Date, Atushi Kobayashi
  • Patent number: 5986046
    Abstract: An oxidant solution for synthesizing a heat-resistant electroconductive polymer, composed of a solution of a non-protonic organic solvent and an oxidant of the organic compound iron salt expressed by the following formula:Fe.sup.3+O [(X)L--(M)m--(Y.sup.-)n]pH.sup.
    Type: Grant
    Filed: March 9, 1998
    Date of Patent: November 16, 1999
    Assignee: NEC Corporation
    Inventors: Toshihiko Nishiyama, Takashi Fukaumi, Atushi Kobayashi, Masashi Ohi, Yoshihiko Saiki, Kazuaki Fukushima, Tomitaro Hara, Shinji Takeoka, Kimihisa Yamamoto, Eishun Tuchida
  • Patent number: 5972052
    Abstract: A fabrication method of a solid electrolytic capacitor is provided, which is able to form the surface irregularity of a conductive polymer layer serving as a solid electrolyte with good controllability and good stability. A capacitor body is formed by a valve metal. The body serves as an anode of the capacity. An oxide layer is formed to cover the surface of the capacitor body. The oxide layer serves as a dielectric of the capacitor. A first conductive polymer layer is formed on the oxide layer. The first conductive polymer layer serves as a part of a solid electrolyte of the capacitor. A powder of a conductive polymer is deposited on the first conductive polymer layer by spraying a fluid containing the powder on the first conductive polymer. A second conductive polymer layer is formed on the first conductive polymer layer to cover the deposited powder. The surface of the second conductive polymer layer has irregularities corresponding to the deposited powder.
    Type: Grant
    Filed: May 30, 1997
    Date of Patent: October 26, 1999
    Assignee: NEC Corporation
    Inventors: Atsushi Kobayashi, Takashi Fukaumi, Tomohide Date, Masashi Ooi
  • Patent number: 5959832
    Abstract: A heat resistant derivative conductive polymer containing nitrogen atoms exclusively in units of polyaniline or a derivative thereof contains a sulfonic acid compound as a dopant, and the percentage of sulfonic acid groups per recurring unit of the polyaniline or derivative thereof is set to 28 to 40%. Also, a solid electrolytic capacitor uses a solid electrolyte of polyaniline or derivative thereof containing a sulfonic acid compound as a dopant, wherein the percentage of sulfonic acid groups per recurring unit of polyaniline or derivative thereof is set to 28 to 40%. In this selected range of the concentration of the dopant, the conductivity and the pyrolysis commencement temperature characteristics are excellent.
    Type: Grant
    Filed: February 28, 1997
    Date of Patent: September 28, 1999
    Assignee: NEC Corporation
    Inventors: Atsushi Kobayashi, Takashi Fukaumi, Kosuke Amano, Hitoshi Ishikawa, Masaharu Satoh
  • Patent number: 5951721
    Abstract: A thick layer of polyaniline is evenly and efficiently deposited on the surface as well as the edges of an anode porous metal. A porous film-forming metal or porous valve metal is immersed in an anilinum protonic salt solution of a high temperature and a high concentration, thereafter, anilinum protonic salt crystals are deposited on the surface of the porous metal by cooling the porous metal to or below the dissolution temperature of the solution, and the porous metal is immersed in an oxidant solution.
    Type: Grant
    Filed: April 17, 1997
    Date of Patent: September 14, 1999
    Assignee: NEC Corporation
    Inventors: Atsushi Kobayashi, Hiroshi Yageta, Tomohide Date, Takashi Fukaumi
  • Patent number: 5951840
    Abstract: The solid electrolytic capacitor comprises a sealed capacitor element having, as a solid electrolyte layer, a heat resistant conductive layer formed on a dielectric oxide film. The heat resistant conducting polymer layer contains water, and the capacitor element inside is substantially oxygen-free. A cathode conductive layer is provided on the capacitor element and then both an external cathode lead and an external anode lead are mounted on the capacitor element. Water is supplied to the conducting polymer layer of the capacitor element such that the conducting polymer layer inside contains water. The capacitor element is then sealed such that water is held within the heat resistant conducting polymer layer and that the capacitor element inside is substantially oxygen-free. The step of supplying water is carried out by dipping the heat resistant conducting polymer layer in water or heavy water or exposed to water-containing inert gas.
    Type: Grant
    Filed: December 28, 1995
    Date of Patent: September 14, 1999
    Assignee: NEC Corporation
    Inventors: Takashi Fukaumi, Toshihiko Nishiyama, Atsushi Kobayashi, Masashi Ohi, Eishun Tsuchida, Kumihisa Yamamoto, Shinji Takeoka, Yoshitaka Fujishima
  • Patent number: 5694287
    Abstract: The solid electrolytic capacitor disclosed has a conducting polymer as a solid electrolyte and an antioxidant contained substantially only in a layer disposed in the neighborhood of a surface of the conducting polymer. The antioxidant serves to block the progress of oxidation of organic materials. A capacitor element with conducting polymer not containing the antioxidant is first prepared and this capacitor element is then dipped in a solution containing the antioxidant. Thus, the antioxidant at high concentration is caused to be introduced into the conducting polymer so as to be contained substantially only in a layer disposed in the neighborhood of the surface of the conducting polymer. Since the antioxidant can be introduced by merely dipping the capacitor element in the antioxidant solution, the method can be applied widely to capacitors irrespective of the process of conducting polymer formation.
    Type: Grant
    Filed: August 30, 1995
    Date of Patent: December 2, 1997
    Assignee: NEC Corporation
    Inventors: Toshihiko Nishiyama, Takashi Fukaumi, Satoshi Arai, Hiromichi Taniguchi, Atsushi Kobayashi
  • Patent number: 5621608
    Abstract: In a solid electrolytic capacitor which employs a conducting polymer as the solid electrolyte, a first solid electrolytic layer (3) consisting of a sole conducting polymer is formed by chemical polymerization on an oxide film (2) formed on the surface of an anode body (1). Next, a second solid electrolytic layer (4) consisting of a conducting polymer containing fine powder, obtained by chemical polymerization using a solution in which fine powder is dispersed in a reaction solution for chemical polymerization, is formed on the first solid electrolytic layer (3). The fine powder is harder than the conducting polymer. With this arrangement, it is possible to prevent the application of a stress to the oxide film (2) by the solid electrolytic layer (4) consisting of a conducting polymer containing fine powder even if there is generated a stress at the time of curing of a molded resin (8).
    Type: Grant
    Filed: November 24, 1995
    Date of Patent: April 15, 1997
    Assignee: NEC Corporation
    Inventors: Satoshi Arai, Takashi Fukaumi, Toshihiko Nishiyama, Hiromichi Taniguchi, Atsushi Kobayashi
  • Patent number: 5586000
    Abstract: The present invention provides a solid electrolytic capacitor comprising a metal having a dielectric oxide film formed thereon, a conductive polymer compound layer formed on said dielectric oxide film, a conductive paste layer formed on said conductive polymer compound layer, a molded resin sheathing having all of the above members buried therein, and a pair of electrodes connected to said metal and said conductive paste layer, respectively, in which capacitor an antioxidant is scattered, in the form of particles, in at least one of said conductive polymer compound layer, said conductive paste layer and the interface between the conductive polymer compound layer and the conductive paste layer; and a process for production of said capacitor.
    Type: Grant
    Filed: December 21, 1994
    Date of Patent: December 17, 1996
    Assignee: NEC Corporation
    Inventors: Koji Sakata, Maki Minamoto, Takashi Fukaumi, Toshihiko Nishiyama, Satoshi Arai, Hiromichi Taniguchi