Patents by Inventor Shinobu Fujiwara

Shinobu Fujiwara 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: 4854936
    Abstract: A semiconductive ceramic composition capable of exhibiting excellent electrical and physical characteristics sufficient to be used for a boundary-layer type semiconductive ceramic capacitor and such a capacitor capable of being increased in dielectric constant and insulation resistance and exhibiting excellent solderability and tensile strength of electrodes. The composition includes a SrTiO.sub.3 base material and an additive for semiconductivity consisting of Y.sub.2 O.sub.3 and Nb.sub.2 O.sub.5. The Y.sub.2 O.sub.3 and Nb.sub.2 O.sub.5 each are present in an amount of 0.1 to 0.4 mol % based on the composition. The capacitor includes a semiconductive ceramic body formed of the composition, a first conductive layer formed on each of both surfaces of the body and a second conductive layer formed on the first conductive layer. A process for manufacturing the capacitor is also provided.
    Type: Grant
    Filed: November 15, 1988
    Date of Patent: August 8, 1989
    Assignee: TDK Corporation
    Inventors: Shuichi Ono, Shuichi Itagaki, Masahiro Yahagi, Kiyoshi Furukawa, Shinobu Fujiwara, Yasunobu Oikawa
  • Patent number: 4799127
    Abstract: A semiconductive ceramic composition capable of exhibiting excellent electrical and physical characteristics sufficient to be used for a boundary-layer type semiconductive ceramic capacitor and such a capacitor capable of being increased in dielectric constant and insulation resistance and exhibiting excellent solderability and tensile strength of electrodes. The composition includes a SrTiO.sub.3 base material and an additive for semiconductivity consisting of Y.sub.2 O.sub.3 and Nb.sub.2 O.sub.5. The Y.sub.2 O.sub.3 and Nb.sub.2 O.sub.5 each are present in an amount of 0.1 to 0.4 mol % based on the composition. The capacitor includes a semiconductive ceramic body formed of the composition, a first conductive layer formed on each of both surfaces of the body and a second conductive layer formed on the first conductive layer. A process for manufacturing the capacitor is also provided.
    Type: Grant
    Filed: July 29, 1987
    Date of Patent: January 17, 1989
    Assignee: TDK Corporation
    Inventors: Shuichi Ono, Shuichi Itagaki, Masahiro Yahagi, Kiyoshi Furukawa, Shinobu Fujiwara, Yasunobu Oikawa
  • Patent number: 4692422
    Abstract: A high dielectric porcelain composition having, as a main component, a Pb(Mg 1/3, Nb 2/3)O.sub.3 -PbTiO.sub.3 -Pb(Mn 1/3, Nb 2/3)O.sub.3 system including 95 mol. % of Pb(Mg 1/3, Nb 2/3)O.sub.3, 5 mol. % of PbTiO.sub.3 and 0.5 weight % of Pb(Mn 1/3, Nb 2/3)O.sub.3, and, in addition, a sub-component including PbO and ZnO. Such a dielectric porcelain is capable of being sintered at a temperature lower than 1000.degree. C. A method of reducing the sintering temperature of such a high dielectric porcelain composition, is also provided.
    Type: Grant
    Filed: May 2, 1986
    Date of Patent: September 8, 1987
    Assignee: TDK Corporation
    Inventors: Shinobu Fujiwara, Atsushi Satoh, Tetsuya Hattori, Junichi Sutoh
  • Patent number: 4447549
    Abstract: A D-E hysteresis loop of ferroelectrics known in the art has a square shape when the ferroelectrics are a BaTiO.sub.3 single crystal. Such ferroelectrics are used as a non-linear dielectric element of, for example a pulse generating device. The non-linear dielectric element according to the present invention consists of a polycrystal, which is mainly composed of BaTiO.sub.3 and has the chemical composition expressed by the formula A.sub.y B.sub.z O.sub.3, wherein the molar ratio of y/z ranges from 0.92 to 0.99. The non-linearity is excellent and the temperature dependence of the A.sub.y B.sub.z O.sub.3 composition is considerably low.
    Type: Grant
    Filed: March 22, 1983
    Date of Patent: May 8, 1984
    Assignee: TDK Kabushiki Kaisha
    Inventors: Sho Masujima, Masahide Shibuya, Iwaya Shoichi, Kenichi Umeda, Yasunobu Oikawa, Hisao Abe, Yoshifumi Midori, Shinobu Fujiwara, Nobuaki Kikuchi
  • Patent number: 4428661
    Abstract: A magnetic brush developing device for developing an electrostatic latent image formed on a charge retaining member includes a housing for containing developer, a developing sleeve arranged rotatably in the housing, a plurality of magnets interior of the developing sleeve, a doctor blade for regulating a thickness of a developer layer formed on a circumferential surface of the developing sleeve by a magnetic flux of the magnets, and a magnetic material fixed on an internal surface of the housing and downstream of the doctor blade as viewed from the direction of the rotation of the developing sleeve. The magnetic material extends in the direction of the width of the developing sleeve, is spaced from the circumferential surface of the developing sleeve, and is positioned opposite to at least one of the magnets arranged in the developing sleeve.
    Type: Grant
    Filed: February 12, 1982
    Date of Patent: January 31, 1984
    Assignee: Konishiroku Photo Industry Co., Ltd.
    Inventors: Keiji Masuda, Shinobu Fujiwara, Kenichi Matsumoto
  • Patent number: 4363088
    Abstract: The invention provides a novel electric power source unit such as a high-speed pulse power source unit built with a pulse-forming circuit and a DC electric power source unit built with a high-frequency voltage-multipler rectifying circuit having high performance in comparison with conventional units. The inventive unit comprises, as a part of the circuit, at least one ceramic capacitor composed of a ceramic dielectric body made of a strontium titanate-based composition unlike the conventional ones in the prior art comprising barium titanate-based ceramic capacitors. Four classes of the preferred compositions are disclosed each containing strontium titanate as the principal component.
    Type: Grant
    Filed: January 8, 1981
    Date of Patent: December 7, 1982
    Assignee: TDK Electronics Co., Ltd.
    Inventors: Hirotaka Yamamoto, Minoru Obara, Shinobu Fujiwara
  • Patent number: 4287075
    Abstract: A novel ceramic composition exhibiting a solid solution structure of Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3 -Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3 -Pb(Mg.sub.1/2 W.sub.1/2)O.sub.3, can be sintered at a low sintering temperature; have a high insulation resistance; have a relatively high dielectric constant in the high dielectric type ceramic dielectrics, and; have a low dielectric loss.A particular amount of the additives, i.e., Pb-(Mn.sub.2/3 W.sub.1/3)O.sub.3, Pb(Mb.sub.1/2 W.sub.1/2)O.sub.3 Pb(Mn.sub.1/2 Nb.sub.2/3)O.sub.3, MnO, Pb(Mn.sub.1/3 Ta.sub.2/3)O.sub.3, Li.sub.2 O, Cr.sub.2 O.sub.3 and CeO.sub.2, is added into the composition mentioned above.
    Type: Grant
    Filed: April 16, 1979
    Date of Patent: September 1, 1981
    Assignee: TDK Electronics Co., Ltd.
    Inventors: Shinobu Fujiwara, Kiyoshi Furukawa, Nobuaki Kikuchi, Osamu Iizawa, Hitoshi Tanaka, Hisayoshi Ueoka
  • Patent number: 4265668
    Abstract: A basic ceramic composition of high dielectric constant type ceramic composition comprises from 68.67 to 69.19% of PbO, from 3.67 to 4.09% of MgO, from 24.17 to 26.99% of Nb.sub.2 O.sub.5 and from 0.25 to 2.97% of TiO.sub.2, all percentages being by weight. Modified composition may comprise additive of Pb(Mn.sub.2/3 W.sub.1/3)O.sub.3, Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3, Pb(Mn.sub.1/3 Ta.sub.2/3)O.sub.3, Pb(Mn.sub.1/2 W.sub.1/2)O.sub.3, MnO, and MgO. Modified composition may comprise Ba, Sr and Ca, which replace Pb of the basic ceramic composition. In a modified composition, the content of B site elements may be larger than that of A site element of an ABO.sub.3 crystal of the high dielectric constant type ceramic composition. A high dielectric constant, low dielectric loss, low temperature dependence of capacitance, high insulation resistance and a low sintering temperature are provided by the ceramic compositions of the present invention.
    Type: Grant
    Filed: October 29, 1979
    Date of Patent: May 5, 1981
    Assignee: TDK Electronics Co., Ltd.
    Inventors: Shinobu Fujiwara, Kiyoshi Furukawa, Nobuaki Kikuchi, Osamu Iizawa, Hitoshi Tanaka
  • Patent number: 4235635
    Abstract: A novel ceramic composition exhibiting a solid solution structure of Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 --Pb(ZrO.sub.3), can be sintered at a low sintering temperature; have a high insulation resistance; have a relatively high dielectric constant in the high dielectric type ceramic dielectrics; have a low dependence of dielectric constant upon temperature, and; have a low dielectric loss.A particular amount of the additives, i.e., MnO, Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3, Pb(Mn.sub.1/2 W.sub.1/2)O.sub.3, Pb(Mn.sub.2/3 W.sub.1/3)O.sub.3, Pb(Mn.sub.1/3 Ta.sub.2/3)O.sub.3, Cr.sub.2 O.sub.3 and CeO.sub.2, is added into the composition mentioned above.
    Type: Grant
    Filed: July 26, 1979
    Date of Patent: November 25, 1980
    Assignee: TDK Electronics Co., Inc.
    Inventors: Osamu Iizawa, Shinobu Fujiwara, Hisayoshi Ueoka, Kiyoshi Furukawa, Nobuaki Kikuchi, Hitoshi Tanaka
  • Patent number: 4216102
    Abstract: A novel ceramic composition exhibiting a solid solution structure of Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3 --Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3, can be sintered at a low sintering temperature; have a high insulation resistance; have a relatively high dielectric constant in the high dielectric type ceramic dielectrics, and; have a low dielectric loss.A particular amount of the additives, i.e., pb(Mn.sub.1/2 W.sub.1/2)O.sub.3, Pb(Mn.sub.1/3 Nb.sub.2/3)O.sub.3, MnO, Pb(Mn.sub.1/3 Ta.sub.2/3)O.sub.3 Li.sub.2 O, Cr.sub.2 O.sub.3 and CeO.sub.2, is added into the composition mentioned above.
    Type: Grant
    Filed: April 6, 1979
    Date of Patent: August 5, 1980
    Assignee: TDK Electronics Co., Ltd.
    Inventors: Kiyoshi Furukawa, Shinobu Fujiwara, Nobuaki Kikuchi, Osamu Iizawa, Hitoshi Tanaka, Hisayoshi Ueoka
  • Patent number: 4216103
    Abstract: A novel ceramic composition exhibiting a solid solution structure of Pb(Fe.sub.1/2 Nb.sub.178 )O.sub.3 -Pb(Mg.sub.1/3 Ta.sub.2/3)O.sub.3, can be sintered at a low sintering temperature; have a high insulation resistance; have a relatively high dielectric constant in the high dielectric type ceramic dielectrics, and; have a low dielectric loss.A particular amount of the additives, i.e., Pb(Mn.sub.1/2 W.sub.1/2)O.sub.3, Pb(Mn.sub.1/3 Nb.sub.170 )O.sub.3, MnO, Pb(Mn.sub.1/3 Ta.sub.170 )O.sub.3, Li.sub.2 O, Cr.sub.2 O.sub.3 and CeO.sub.2, is added into the composition mentioned above.
    Type: Grant
    Filed: April 6, 1979
    Date of Patent: August 5, 1980
    Assignee: TDK Electronics Co., Ltd.
    Inventors: Shinobu Fujiwara, Kiyoshi Furukawa, Nobuaki Kikuchi, Osamu Iizawa, Hitoshi Tanaka, Hisayoshi Ueoka
  • Patent number: 4119554
    Abstract: A ceramic dielectric composition is provided including 35 to 93.5% by weight of SrTiO.sub.3, 4 to 40% by weight of Bi.sub.2 O.sub.3, at least 2.5% but less than 60% by weight of TiO.sub.2, and 0.1 to 5.0% by weight, of an alkali metal oxide based on the total amount of SrTiO.sub.3, Bi.sub.2 O.sub.3 and TiO.sub.2. The ceramic dielectric composition has a high dielectric constant and low dielectric loss and exhibits reduced variations of dielectric constant and the dielectric loss with respect to variation of an applied voltage.
    Type: Grant
    Filed: August 10, 1977
    Date of Patent: October 10, 1978
    Assignee: TDK Electronics Co., Ltd.
    Inventor: Shinobu Fujiwara
  • Patent number: 4073846
    Abstract: An improved reduction-reoxidation type semiconducting ceramic capacitor and the method for producing the same are disclosed. The main components of the substrate of the capacitor are CaTiO.sub.3, SrTiO.sub.3 and Bi.sub.2 O.sub.3 .multidot.xTiO.sub.2. Said substrate also contains at least one member selected from the group consisting of manganese, cobalt, nickel, chromium, vanadium, niobium, tantalum, lanthanum and cerium ions in total amounts of 0.025 to 0.4% by weight. The capacitor according to the present invention excels, in the temperature independency of the capacitance and tan .delta., etc.
    Type: Grant
    Filed: February 3, 1976
    Date of Patent: February 14, 1978
    Assignee: TDK Electronics Co., Ltd.
    Inventors: Hitoshi Masumura, Shinobu Fujiwara, Hitoshi Tanaka
  • Patent number: 4058404
    Abstract: A sintered ceramic dielectric body is provided which exhibits a high dielectric constant as well as a low dielectric loss and almost no variation in the dielectric constant and the dielectric loss with respect to a wide variation of an applied high AC or DC voltage, respectively. The ceramic dielectric composition consists essentially, by weight, of approximately 18 to 70% of strontium titanate (SrTiO.sub.3), approximately 4 to 75% of barium titanate (BaTiO.sub.3), 2.5 to 17.4% of bismuth oxide (Bi.sub.2 O.sub.3) and 1.7 to approximately 20% of titanium oxide (TiO.sub.2); the ratio by mole of the titanium oxide (TiO.sub.2) to the bismuth oxide (Bi.sub.2 O.sub.3) being within the range from approximately 1 to 18.
    Type: Grant
    Filed: September 16, 1975
    Date of Patent: November 15, 1977
    Assignee: TDK Electronics Co., Ltd.
    Inventors: Shinobu Fujiwara, Hitoshi Tanaka
  • Patent number: 4017320
    Abstract: A ceramic dielectric composition is provided including 30 to 94% by mol of SrTiO.sub.3, 1 to 22% by mol of Bi.sub.2 O.sub.3 and 5 to 69% by mol of TiO.sub.2, and further including 0.1 to 20% by weight of MgO with respect to the total weight of the above-mentioned three compounds SrTiO.sub.3, Bi.sub.2 O.sub.3 and TiO.sub.2, whereby the ceramic dielectric composition has a high dielectric constant and a low dielectric loss and further the variations of the dielectric constant and the dielectric loss with respect to the variation of an applied voltage, are respectively, very small.
    Type: Grant
    Filed: November 19, 1975
    Date of Patent: April 12, 1977
    Assignee: TDK Electronics Company, Limited
    Inventors: Shinobu Fujiwara, Hitoshi Tanaka
  • Patent number: 4014707
    Abstract: A dielectric ceramic composition comprises as principle constituents, 86 - 99.6 mole % of barium titanate, 0.2 - 10 mole % of niobium pentaoxide and 0.2 - 4 mole % of cerium oxide.
    Type: Grant
    Filed: July 8, 1975
    Date of Patent: March 29, 1977
    Assignee: TDK Electronics Company, Limited
    Inventors: Hitoshi Tanaka, Hitoshi Masumura, Shinobu Fujiwara
  • Patent number: 3995300
    Abstract: An improved reduction-reoxidation type semiconducting ceramic capacitor and the method for producing the same are disclosed. The main components of the substrate of the capacitor are CaTiO.sub.3, SrTiO.sub.3 and Bi.sub.2 O.sub.3.xTiO.sub.2. Said substrate also contains at least one member selected from the group consisting of manganese, cobalt, nickel, chromium, vanadium, niobium, tantalum, lanthanum and cerium ions in total amounts of 0.025 to 0.4% by weight. The capacitor according to the present invention excels, in the temperature independency of the capacitance and tan .delta., etc.
    Type: Grant
    Filed: August 14, 1974
    Date of Patent: November 30, 1976
    Assignee: TDK Electronics Company, Limited
    Inventors: Hitoshi Masumura, Shinobu Fujiwara, Hitoshi Tanaka
  • Patent number: 3951873
    Abstract: A ceramic dielectric composition which comprises 22.5-45.2 wt. % SrO, 8.3-20.6 wt. % CaO, 29.3-80.8 wt. % TiO.sub.2, and 0.07-8.3 wt. % MgO as main components.
    Type: Grant
    Filed: August 2, 1974
    Date of Patent: April 20, 1976
    Assignee: TDK Electronics Company, Limited
    Inventors: Nobuaki Kikuchi, Tsunehiko Yoshioka, Kiyoshi Furukawa, Shinobu Fujiwara