Patents by Inventor Seishiro Yamakawa

Seishiro Yamakawa 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).

  • Glass fiber forming composition, glass fibers obtained from the composition and substrate for circuit board including the glass fibers as reinforcing material
    Patent number: 5407872
    Abstract: A glass fiber forming composition exhibits a remarkably high dielectric constant .epsilon..sub..GAMMA. as well as superior chemical resistance, yet it is readily spun into glass fibers. The composition is characterized to show a devitrification temperature which is lower than a spinning temperature at which the glass composition exhibits a viscosity of 10.sup.2.5 poise, so as to be readily spun into corresponding glass fibers. The composition consists essentially of 40 to 65 mol % of SiO.sub.2 ; 20 to 45 mol % of at least one component selected from the group consisting of MgO, CaO, SrO and BaO; 5 to 25 mol % of at least one component selected from the group consisting of TiO.sub.2 and ZrO.sub.2 ; and 0.5 to 15 mol % of NbO.sub.5/2 as calculated from an incorporated amount of Nb.sub.2 O.sub.5. Alternately, the composition consist essentially of 40 to 65 mol % of SiO.sub.
    Type: Grant
    Filed: November 8, 1993
    Date of Patent: April 18, 1995
    Assignees: Matsushita Electric Works Ltd., Nippon Electric Glass Co. Ltd.
    Inventors: Kiyotaka Komori, Seishiro Yamakawa, Shigeru Yamamoto, Jun Naka, Tadashi Kokubo
  • Substrate for circuit board including the glass fibers as reinforcing material
    Patent number: 5334645
    Abstract: A glass fiber forming composition exhibits a remarkably high dielectric constant .epsilon..sub.r as well as superior chemical resistance, yet it is readily spun into glass fibers. The composition is characterized to show a devitrification temperature which is lower than a spinning temperature at which the glass composition exhibits a viscosity of 10.sup.2.5 poise, so as to be readily spun into corresponding glass fibers. The composition consists essentially of 40 to 65 mol % of SiO.sub.2 ; 20 to 45 mol % of at least one component selected from the group consisting of MgO, CaO, SrO and BaO; 5 to 25 mol % of at least one component selected from the group consisting of TiO.sub.2 and ZrO.sub.2 ; and 0.5 to 15 mol % of NbO.sub.5/2 as calculated from an incorporated amount of Nb.sub.2 O.sub.5. Alternately, the composition consist essentially of 40 to 65 mol % of SiO.sub.
    Type: Grant
    Filed: November 8, 1993
    Date of Patent: August 2, 1994
    Assignees: Matsushita Electric Works, Ltd., Nippon Electric Glass Co., Ltd.
    Inventors: Kiyotaka Komori, Seishiro Yamakawa, Shigeru Yamamoto, Jun Naka, Tadashi Kokubo
  • Glass fiber forming composition, glass fibers obtained from the composition and substrate for circuit board including the glass fibers as reinforcing material
    Patent number: 5284807
    Abstract: A glass fiber forming composition exhibits a remarkably high dielectric constant .epsilon..sub.r as well as superior chemical resistance, yet it is readily spun into glass fibers. The composition is characterized to show a devitrification temperature which is lower than a spinning temperature at which the glass composition exhibits a viscosity of 10.sup.2.5 poise, so as to be readily spun into corresponding glass fibers. The composition consists essentially of 40 to 65 mol % of SiO.sub.2 ; 20 to 45 mol % of at least one component selected from the group consisting of MgO, CaO, SrO and BaO; 5 to 25 mol % of at least one component selected from the group consisting of TiO.sub.2 and ZrO.sub.2 ; and 0.5 to 15 mol % of NbO.sub.5/2 as calculated from an incorporated amount of Nb.sub.2 O.sub.5. Alternately, the composition consist essentially of 40 to 65 mol % of SiO.sub.
    Type: Grant
    Filed: February 7, 1992
    Date of Patent: February 8, 1994
    Assignees: Matsushita Electric Works, Ltd., Nippon Electric Glass Co., Ltd.
    Inventors: Kiyotaka Komori, Seishiro Yamakawa, Shigeru Yamamoto, Jun Naka, Tadashi Kukubo
  • Composite dielectric and printed-circuit use substrate utilizing the same
    Patent number: 5275878
    Abstract: A composite dielectric is formed with a matrix synthetic resin and particulate porous, inorganic dielectric dispersed in the matrix synthetic resin. The dielectric constant of this composite dielectric can be thereby elevated effectively without enlarging the dissipation factor (tan .delta.) of the composite dielectric.
    Type: Grant
    Filed: January 31, 1991
    Date of Patent: January 4, 1994
    Assignees: Matsushita Electric Works, Ltd., Sakai Chemical Industry Co., Ltd.
    Inventors: Seishiro Yamakawa, Michimasa Tsuzaki, Kiyotaka Komori, Satoshi Fujiki, Akiyoshi Nozue, Kazunobu Abe, Masashi Aoki