Patents by Inventor Mitsutoshi Kawamoto

Mitsutoshi Kawamoto 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: 6838117
    Abstract: A method for producing a lead ferroelectric film having high relative dielectric constant and low dielectric loss by a hydrothermal process is disclosed. The method includes the step of hydrothermally forming a ferroelectric layer on a substrate, followed by the step of hydrothermally treating the resulting film in an aqueous solution having a pH of about 5 to 7.
    Type: Grant
    Filed: January 17, 2003
    Date of Patent: January 4, 2005
    Assignee: Murata Manufacturing Co., Ltd.
    Inventor: Mitsutoshi Kawamoto
  • Patent number: 6791179
    Abstract: A monolithic semiconducting ceramic electronic component includes barium titanate-based semiconducting ceramic layers and internal electrode layers alternately deposited, and external electrodes electrically connected to the internal electrode layers. The semiconducting ceramic layers contain ceramic particles having an average particle size of about 1 &mgr;m or less and the average number of ceramic particles per layer in the direction perpendicular to the semiconductor layers is about 10 or more. The internal electrode layers are preferably composed of a nickel-based metal.
    Type: Grant
    Filed: May 29, 2003
    Date of Patent: September 14, 2004
    Assignee: Murata Manufacturing Co., Ltd.
    Inventor: Mitsutoshi Kawamoto
  • Patent number: 6680527
    Abstract: A monolithic semiconducting ceramic electronic component includes barium titanate-based semiconducting ceramic layers and internal electrode layers alternately deposited, and external electrodes electrically connected to the internal electrode layers. The semiconducting ceramic layers contain ceramic particles having an average particle size of about 1 &mgr;m or less and the average number of ceramic particles per layer in the direction perpendicular to the semiconductor layers is about 10 or more. The internal electrode layers are preferably composed of a nickel-based metal.
    Type: Grant
    Filed: October 25, 1999
    Date of Patent: January 20, 2004
    Assignee: Murata Manufacturing Co. Ltd.
    Inventor: Mitsutoshi Kawamoto
  • Publication number: 20030205803
    Abstract: A monolithic semiconducting ceramic electronic component includes barium titanate-based semiconducting ceramic layers and internal electrode layers alternately deposited, and external electrodes electrically connected to the internal electrode layers. The semiconducting ceramic layers contain ceramic particles having an average particle size of about 1 &mgr;m or less and the average number of ceramic particles per layer in the direction perpendicular to the semiconductor layers is about 10 or more. The internal electrode layers are preferably composed of a nickel-based metal.
    Type: Application
    Filed: May 29, 2003
    Publication date: November 6, 2003
    Applicant: Murata Manufacturing Co., Ltd.
    Inventor: Mitsutoshi Kawamoto
  • Publication number: 20030143333
    Abstract: A method for producing a lead ferroelectric film having high relative dielectric constant and low dielectric loss by a hydrothermal process is disclosed. The method includes the step of hydrothermally forming a ferroelectric layer on a substrate, followed by the step of hydrothermally treating the resulting film in an aqueous solution having a pH of about 5 to 7.
    Type: Application
    Filed: January 17, 2003
    Publication date: July 31, 2003
    Inventor: Mitsutoshi Kawamoto
  • Patent number: 6544443
    Abstract: The semiconducting ceramic material of the present invention containing BaTiO3 and having a positive temperature coefficient of resistance is endowed with high withstand voltage. In the semiconducting ceramic material, a boundary temperature defined at the boundary between a first temperature range and a second temperature range is 180° C. or more (e.g., 370° C.) higher than the Curie temperature, wherein the first temperature range is higher than the Curie temperature and the ceramic material has a positive temperature coefficient of resistance in the range, and the second temperature range is higher than the first temperature range and the ceramic material has a negative temperature coefficient of resistance in the range.
    Type: Grant
    Filed: December 5, 2000
    Date of Patent: April 8, 2003
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Hideaki Niimi, Akira Ando, Mitsutoshi Kawamoto, Masahiro Kodama
  • Patent number: 6542067
    Abstract: A compact and low resistance laminated semiconductor ceramic device which is provided with a positive resistance-temperature characteristic and has a broad resistance-change range and a high breakdown voltage in addition to ohmic contact between semiconductor ceramic layers and internal electrodes is provided. A doped barium titanate semiconductor ceramic having an average particle diameter of not more than about 1.0 &mgr;m, a c/a axis ratio of not less than about 1.005, and a barium site/titanium site ratio from about 0.99 to 1.01, in which a donor element, such as lanthanum (La), is used.
    Type: Grant
    Filed: May 22, 2000
    Date of Patent: April 1, 2003
    Assignee: Murata Manufacturing Co., Ltd.
    Inventor: Mitsutoshi Kawamoto
  • Publication number: 20030030192
    Abstract: A BaTiO3-type semiconducting ceramic material which has undergone firing in a reducing atmosphere and re-oxidation, wherein the relative density of the ceramic material after sintering is about 85-90%. A process for producing the semiconducting ceramic material of the present invention and a thermistor containing the semiconducting ceramic material are also disclosed.
    Type: Application
    Filed: September 18, 2002
    Publication date: February 13, 2003
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Hideaki Niimi, Akira Ando, Mitsutoshi Kawamoto, Masahiro Kodama
  • Publication number: 20030022784
    Abstract: The present invention provides barium titanate semiconductive ceramic having low specific resistance at room temperature and high withstand voltage, which fully satisfies the demand for enhancing withstand voltage. The average ceramic grain size of the barium titanate semiconductive ceramic is controlled to about 0.9 &mgr;m or less. By this control, the ceramic possesses low specific resistance at room temperature and high withstand voltage fully satisfying a recent demand for enhancing withstand voltage and may suitably used for applications such as controlling temperature and limiting current, or in exothermic devices for constant temperature. Accordingly, the barium titanate semiconductive ceramic enables an apparatus using the same to have enhanced performance and reduced size.
    Type: Application
    Filed: September 13, 2002
    Publication date: January 30, 2003
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Mitsutoshi Kawamoto, Hideaki Niimi, Ryouichi Urahara, Yukio Sakabe
  • Patent number: 6472339
    Abstract: The present invention provides barium titanate semiconductive ceramic having low specific resistance at room temperature and high withstand voltage, which fully satisfies the demand for enhancing withstand voltage. The average ceramic grain size of the barium titanate semiconductive ceramic is controlled to about 0.9 &mgr;m or less. By this control, the ceramic possesses low specific resistance at room temperature and high withstand voltage fully satisfying a recent demand for enhancing withstand voltage and may suitably used for applications such as controlling temperature and limiting current, or in exothermic devices for constant temperature. Accordingly, the barium titanate semiconductive ceramic enables an apparatus using the same to have enhanced performance and reduced size.
    Type: Grant
    Filed: September 18, 1998
    Date of Patent: October 29, 2002
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Mitsutoshi Kawamoto, Hideaki Niimi, Ryouichi Urahara, Yukio Sakabe
  • Publication number: 20020130318
    Abstract: A ceramic electronic component includes a component body having semiconductive ceramic layers and internal electrodes. The semiconductive ceramic layers and the internal electrodes are alternately laminated. The semiconductive ceramic layers have a relative density of about 90% or less and contain no sintering additives. The component body is provided with an external electrode on each side thereof. The ceramic electronic component has a low resistance and a high withstand voltage.
    Type: Application
    Filed: December 18, 2001
    Publication date: September 19, 2002
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Masahiro Kodama, Atsushi Kishimoto, Mitsutoshi Kawamoto, Hideaki Niimi, Akira Ando
  • Publication number: 20020105022
    Abstract: A monolithic semiconducting electronic component includes barium titanate-based semiconducting ceramic layers and internal electrode layers, which are alternately laminated, and external electrodes arranged to be electrically connected to the internal electrode layers. The ratio S/I of the thickness S of each of the semiconducting ceramic layers to the thickness I of each of the internal electrode layers is about 10 to about 50. Preferably, the internal electrode layers are composed of a nickel-based metal.
    Type: Application
    Filed: December 11, 2000
    Publication date: August 8, 2002
    Applicant: Murata Manufacturing Co., Ltd
    Inventors: Mitsutoshi Kawamoto, Hideaki Niimi, Masahiro Kodama, Atsushi Kishimoto
  • Patent number: 6376079
    Abstract: The present invention provides a semiconducting ceramic which possesses a dielectric strength of 800 V/mm or more and a specific resistance at room temperature of 100 &OHgr;·cm or less, the specific resistance at room temperature undergoing substantially no time-course change. The semiconducting ceramic is formed of a sintered semiconducting material containing barium titanate, wherein the average grain size of the semiconducting ceramic is about 1.0 &mgr;m or less and the relative spectral intensity ratio represented by BaCO3/BaO, which is determined by XPS at the surface of the ceramic, is 0.5 or less.
    Type: Grant
    Filed: March 30, 1999
    Date of Patent: April 23, 2002
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Mitsutoshi Kawamoto, Hideaki Niimi
  • Publication number: 20010008866
    Abstract: The present invention provides barium titanate semiconductive ceramic having low specific resistance at room temperature and high withstand voltage, which fully satisfies the demand for enhancing withstand voltage. The average ceramic grain size of the barium titanate semiconductive ceramic is controlled to about 0.9 &mgr;m or less. By this control, the ceramic possesses low specific resistance at room temperature and high withstand voltage fully satisfying a recent demand for enhancing withstand voltage and may suitably used for applications such as controlling temperature and limiting current, or in exothermic devices for constant temperature. Accordingly, the barium titanate semiconductive ceramic enables an apparatus using the same to have enhanced performance and reduced size.
    Type: Application
    Filed: September 18, 1998
    Publication date: July 19, 2001
    Inventors: MITSUTOSHI KAWAMOTO, HIDEAKI NIIMI, RYOUICHI URAHARA, YUKIO SAKABE
  • Publication number: 20010003361
    Abstract: The semiconducting ceramic material of the present invention containing BaTiO3 and having a positive temperature coefficient of resistance is endowed with high withstand voltage. In the semiconducting ceramic material, a boundary temperature defined at the boundary between a first temperature range and a second temperature range is 180° C. or more (e.g., 370° C.) higher than the Curie temperature, wherein the first temperature range is higher than the Curie temperature and the ceramic material has a positive temperature coefficient of resistance in the range, and the second temperature range is higher than the first temperature range and the ceramic material has a negative temperature coefficient of resistance in the range.
    Type: Application
    Filed: December 5, 2000
    Publication date: June 14, 2001
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Hideaki Niimi, Akira Ando, Mitsutoshi Kawamoto, Masahiro Kodama
  • Patent number: 6162752
    Abstract: The present invention provides barium titanate powder having a withstanding voltage of 800 V/mm or more and a specific resistance at room temperature of 100 .OMEGA..multidot.cm or less, the specific resistance at room temperature undergoing substantially no time-course change. Barium titanate of the powder of the present invention assumes a cubic crystal system. The powder has a particle size of about 0.1 .mu.m or less; the ratio represented by BaCO.sub.3 /BaO as obtained through XPS is about 0.42 or less; the lattice constant is about 0.4020 nm or more; and the ratio represented by Ba/Ti is about 0.988-0.995.
    Type: Grant
    Filed: May 11, 1999
    Date of Patent: December 19, 2000
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Mitsutoshi Kawamoto, Hideaki Niimi
  • Patent number: 6153931
    Abstract: The present invention provides a barium titanate-based semiconducting ceramic which exhibits excellent PTC characteristic and which can be fired at a temperature lower than 1000.degree. C. The present invention also provides an electronic element fabricated from the ceramic. The semiconducting ceramic contains, in a semiconducting sintered barium titanate; boron oxide; an oxide of at least one of barium, strontium, calcium, lead, yttrium and a rare earth element; and an optional oxide of at least one of titanium, tin, zirconium, niobium, tungsten and antimony in which the atomic boron is0.005.ltoreq.B/.beta..ltoreq.0.50 and1.0.ltoreq.B/(.alpha.-.beta.).ltoreq.4.0wherein .alpha. represents the total number of atoms of barium, strontium, calcium, lead, yttrium and rare earth element contained in the semiconducting ceramic, and .beta. represents the total number of atoms of titanium, tin, zirconium, niobium, tungsten and antimony contained in the semiconducting ceramic.
    Type: Grant
    Filed: March 4, 1999
    Date of Patent: November 28, 2000
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Hideaki Niimi, Mitsutoshi Kawamoto, Akinori Nakayama, Satoshi Ueno, Ryouichi Urahara
  • Patent number: 5733832
    Abstract: A dielectric ceramic composition composed mainly of lead magnesium-niobate ?Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3 !, strontium titanate ?SrTiO.sub.3 !, and lead titanate ?PbTiO.sub.3 !, characterized in that the molar ratio of said three major components is defined by?Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3 !.sub.x .multidot.?SrTiO.sub.3 !.sub.y .multidot.?PbTiO.sub.3 !.sub.z(where x+y+z=100 parts by mole, and each value of x, y, and z is on lines or within the area enclosed by lines passing through four points A (72, 10, 18), B (76, 5, 19), C (57, 5, 38), and D (48, 20, 32) in a triangular composition diagrams), and said three major components are supplemented by (Pb.sub.1-x Ba.sub.x) (Cu.sub.1/2 W.sub.1/2)O.sub.3 (where 0.ltoreq.x.ltoreq.1) in an amount less than about 5 parts by mole (excluding 0 part by mole) for 100 parts by mole of said major components. This dielectric ceramic composition can be sintered at low temperatures and has a high permittivity and a high mechanical strength.
    Type: Grant
    Filed: January 27, 1997
    Date of Patent: March 31, 1998
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Mitsutoshi Kawamoto, Yukio Hamaji