Patents by Inventor Masatada Yodogawa

Masatada Yodogawa 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: 6432325
    Abstract: An electron-emitting electrode for discharge lamps etc. uses an electron-emitting material which contains a first metal component selected from Ba, Sr and Ca and a second metal component selected from Ta, Zr, Nb, Ti and Hf and also contains oxynitride perovskite. The electron-emitting material has restrained evaporation during electric discharge and a high resistance to ion sputtering.
    Type: Grant
    Filed: March 2, 2000
    Date of Patent: August 13, 2002
    Assignee: TDK Corporation
    Inventors: Munemitsu Hamada, Akira Takeishi, Makoto Takahashi, Dai Matsuoka, Masatada Yodogawa, Hiraku Harada
  • Patent number: 6383416
    Abstract: An electron-emitting material contains a first metal component selected from Ba, Sr and Ca and a second metal component selected from Ta, Zr, Nb, Ti and Hf and also contains oxynitride perovskite. The electron-emitting material has improved electron emission characteristics, restrained evaporation at elevated temperatures, and minimized consumption by ion sputtering. The electron-emitting material is prepared by firing a metal component-containing raw material disposed in proximity to carbon in a nitrogen gas-containing atmosphere to thereby create oxynitride perovskite.
    Type: Grant
    Filed: March 2, 2000
    Date of Patent: May 7, 2002
    Assignee: TDK Corporation
    Inventors: Munemitsu Hamada, Akira Takeishi, Makoto Takahashi, Dai Matsuoka, Masatada Yodogawa, Hiraku Harada
  • Patent number: 6218928
    Abstract: The PTC thermistor material of the invention comprises a matrix phase and electrically conductive phases substantially uniformly dispersed in the matrix phase, said conductive phases having a resistivity lower than that of the matrix phase, and has a resistivity changing sharply in the vicinity of the melting point of the conductive phases. The matrix phase is made up of any one of a polycrystalline ceramic material, a glass-polycrystalline ceramic composite material, a glass, a crystallized glass, and a polymer material, and the conductive phases are made up of a metal containing bismuth as a main component. It is thus possible to achieve a PTC thermistor material which can be controlled in terms of various properties such as the temperature at which PTCR property becomes available and the rate of resistivity change and so can be applied to circuit parts through which large currents pass in a normal operation state.
    Type: Grant
    Filed: May 8, 1998
    Date of Patent: April 17, 2001
    Assignees: TDK Corporation
    Inventors: Masuo Okada, Takahiro Sawaguchi, Masatada Yodogawa, Dai Matsuoka
  • Patent number: 6140906
    Abstract: A resistive temperature sensor is constituted by an insulating body mainly composed of alumina; and a temperature sensing resistor mainly composed of a conductive material containing a metal silicide. The insulating body and the temperature sensing resistor are laminated and sintered to form a lamination sintered body in which a resistance circuit is formed.
    Type: Grant
    Filed: November 10, 1997
    Date of Patent: October 31, 2000
    Assignee: TDK Corporation
    Inventors: Nobuo Kaihara, Minoru Ogasawara, Masatada Yodogawa
  • Patent number: 5773158
    Abstract: The invention provides a rapid temperature rise heater element comprising an exothermic section (1) and a lead section (2), the exothermic section (1) comprising an exothermic section conductor of ceramic material which includes at least four stacked exothermic section conductive layers (1a) with an exothermic section insulating layer (1c) of ceramic material interposed therebetween and connections (1b) each for connecting adjacent exothermic section conductive layers (1a). The lead section (2) includes first and second lead section conductive layers (2a and 2b) electrically connected to the uppermost and lowermost exothermic section conductive layers (1a), respectively, the first and second lead section conductive layers (2a and 2b) being stacked with a lead section insulating layer (2c) of ceramic material interposed therebetween. A durable rapid temperature rise heater element can be efficiently fabricated at low cost while maintaining heater performance.
    Type: Grant
    Filed: December 27, 1995
    Date of Patent: June 30, 1998
    Assignee: TDK Corporation
    Inventors: Kentaro Sawamura, Etsuo Mitsuhashi, Masaru Nanao, Nobuyuki Miki, Masahiro Kitajima, Masatada Yodogawa
  • Patent number: 5756215
    Abstract: A rectangular plate shaped rapid temperature rise heater element includes a sintered insulating ceramic layer, an exothermic section, and first and second lead layers for applying voltage across the exothermic section to develop heat. Typically the sintered insulating ceramic layer, exothermic section, and lead layers are formed of ceramic compositions composed mainly of an identical insulating component in the form of a metal oxide, typically Al.sub.2 O.sub.3 and an identical conductive component in the form of a metal silicide and/or carbide, typically MoSi.sub.2, blended in different ratios for the respective layers. The heater element is easy and inexpensive to manufacture, capable of rapid heating, and durable.
    Type: Grant
    Filed: July 20, 1994
    Date of Patent: May 26, 1998
    Assignee: TDK Corporation
    Inventors: Kentaro Sawamura, Nobuyuki Miki, Masahiro Kitajima, Etsuo Mitsuhashi, Masatada Yodogawa, Shinichi Sato, Akio Okamura, Ryoichi Kondo
  • Patent number: 5707583
    Abstract: In preparing a zinc oxide base varistor in the form of a sintered body which itself has a voltage-dependent nonlinear resistance, firing is done in an atmosphere containing at least 60% of oxygen at or above the temperature at which additives form a liquid phase, and thereafter the sintered body is heat treated in an atmosphere containing at least 10% of oxygen at a temperature of 600.degree. to 1,000.degree. C. There is obtained a zinc oxide base varistor having a high energy handling capability, a high nonlinearity index .alpha., and satisfactory load life characteristics such as a humid load life.
    Type: Grant
    Filed: May 19, 1995
    Date of Patent: January 13, 1998
    Assignee: TDK Corporation
    Inventor: Masatada Yodogawa
  • Patent number: 5640136
    Abstract: The invention provides a voltage-dependent nonlinear resistor porcelain in the form of a ZnO system sintered body comprising zinc oxide as a major component and at least one of rare earth element oxides, cobalt oxide, chromium oxide, at least one of Group IIIb element oxides, at least one of Group Ia element oxides, 0.01 to 2 atom % calculated as Ca of calcium oxide, and 0.001 to 0.5 atom % calculated as Si of silicon oxide as subordinate components, the atomic ratio of calcium to silicon (Ca/Si) ranging from 0.2 to 20. With the atomic ratio of calcium to silicon (Ca/Si) set between 0.2 and 20, preferably between 2 and 6, the element has a significantly increased load life at high temperature and humidity. The element experiences less deterioration of the asymmetry of its volt-ampere characteristic between different directions of DC conduction. If magnesium oxide is added to the composition in an amount of 0.
    Type: Grant
    Filed: June 9, 1994
    Date of Patent: June 17, 1997
    Assignee: TDK Corporation
    Inventors: Masatada Yodogawa, Toshiyuki Yamazaki, Hitomi Naitou, Masahito Furukawa, Dai Matsuoka
  • Patent number: 4320379
    Abstract: A voltage non-linear resistor comprises a sintered body of a ceramic composition comprising zinc oxide at a ratio of 99.88 to 84.88 mol % as ZnO; a praseodymium oxide component at a ratio of 0.01 to 0.035 mol % as Pr.sub.2 O.sub.3 and a lanthanum oxide component at a ratio of 0.01 to 0.035 mol % as La.sub.2 O.sub.3 and a cobalt oxide component at a ratio of 0.1 to 15 mol % as CoO and a specific additional component selected from chromium oxide, boron oxide, silicon oxide, titanium oxide, tin oxide, zirconium oxide, niobium oxide, tantalum oxide, tungsten oxide and germanium oxide at a ratio of 0.0001 to 0.05 mol %.
    Type: Grant
    Filed: September 8, 1980
    Date of Patent: March 16, 1982
    Assignee: TDK Electronics Co., Ltd.
    Inventor: Masatada Yodogawa
  • Patent number: 4306214
    Abstract: A novel non-linear resistance element or a varistor element is proposed which is a sintered body composed of a ternary oxide mixture comprising titanium dioxide as the base component, bismuth oxide and a third oxide component selected from the group consisting of oxides of tantalum, niobium and antimony admixed in limited proportions. The sintered body is prepared by subjecting the powder mixture obtained by admixing a solution containing tantalum, niobium or antimony with titanium dioxide and bismuth oxide to sintering following drying and calcination. The varistor element of the invention is stable in its performance and has a sufficiently high non-linearity index so that excellent noise suppressors are prepared with the varistor element to be useful in absorbing the noise voltages generated in various rotatory machines such as miniature motors.Further improvement in the above varistor element is proposed by adding a small amount of silicon dioxide to the ternary oxide mixtures.
    Type: Grant
    Filed: August 8, 1979
    Date of Patent: December 15, 1981
    Assignee: TDK Electronics Co., Ltd.
    Inventors: Susumu Miyabayashi, Masatada Yodogawa
  • Patent number: 4254070
    Abstract: A sintered body of a ceramic composition for voltage non-linear resistor is produced by sintering an oxide semiconductor composition comprising a main component of zinc oxide and a minor component at 1100.degree. to 1400.degree. C.; then maintaining the sintered body in an inert gas such as N.sub.2, Ar and so on having an oxygen content of 0.1 to 21 vol. % at the temperature lower than the sintering temperature for a specific time; changing the atmosphere into an inert gas having an oxygen content of lower than 0.02 vol. % at 800.degree. to 1200.degree. C.; and cooling it.
    Type: Grant
    Filed: October 30, 1979
    Date of Patent: March 3, 1981
    Assignee: TDK Electronics Company, Limited
    Inventors: Masatada Yodogawa, Matsuo Morisawa, Takashi Yamamoto, Katsunobu Okutani
  • Patent number: 4160748
    Abstract: A non-linear resistor comprises a sintered body of a ceramic composition which comprises 99.93 to 50 mole % of zinc oxide as ZnO; 0.01 to 10 mole % of a specific rare earth oxide as R.sub.2 O.sub.3 (R represents lanthanum, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium or lutetium) 0.01 to 10 mole % of an alkaline earth oxide as MO (M represents calcium, strontium or barium) and 0.05 to 30 mole % of cobalt oxide as CoO.
    Type: Grant
    Filed: December 23, 1977
    Date of Patent: July 10, 1979
    Assignee: TDK Electronics Co., Ltd.
    Inventors: Masatada Yodogawa, Susumu Miyabayashi, Yoshinari Yamashita, Takashi Yamamoto, Kohji Hayashi, Hisayoshi Ueoka
  • Patent number: 4077915
    Abstract: A non-linear resistor comprises a sintered body of a ceramic composition which comprises 99.94 to 80.0 mole % of zinc oxide as ZnO, 0.02 to 10.0 mole % of the specific rare earth oxide selected from the group consisting of oxides of cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, and lutetium as R.sub.2 O.sub.3, and 0.04 to 10 mole % of manganese oxide as MnO.
    Type: Grant
    Filed: September 2, 1976
    Date of Patent: March 7, 1978
    Assignee: TDK Electronics Co., Ltd.
    Inventors: Masatada Yodogawa, Susumu Miyabayashi, Yoshinari Yamashita, Takashi Yamamoto, Kohji Hayashi, Hisayoshi Ueoka
  • Patent number: 4022716
    Abstract: Semiconducting ceramics are produced by firing a semiconducting composition of the barium titanate type containing vanadium oxide in the amount of 0.001 to 0.5 wt%. A change in the specific resistance over the range of the temperature at which the positive temperature coefficient characteristic of resistivity (PTCR) is exhibited can be increased by as much as 10.sup.5 times and the specific resistance value at room temperature can be controlled at a desired value. By further adding silicon dioxide to the above composition in the amount of 0.05 to 1.5 wt% the above effects can be enhanced, especially the specific resistance at ambient temperature.
    Type: Grant
    Filed: February 17, 1976
    Date of Patent: May 10, 1977
    Assignee: TDK Electronics Company, Limited
    Inventors: Hisayoshi Ueoka, Masatada Yodogawa