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).
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Patent number: 6838117Abstract: 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: GrantFiled: January 17, 2003Date of Patent: January 4, 2005Assignee: Murata Manufacturing Co., Ltd.Inventor: Mitsutoshi Kawamoto
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Patent number: 6791179Abstract: 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: GrantFiled: May 29, 2003Date of Patent: September 14, 2004Assignee: Murata Manufacturing Co., Ltd.Inventor: Mitsutoshi Kawamoto
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Patent number: 6680527Abstract: 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: GrantFiled: October 25, 1999Date of Patent: January 20, 2004Assignee: Murata Manufacturing Co. Ltd.Inventor: Mitsutoshi Kawamoto
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Publication number: 20030205803Abstract: 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: ApplicationFiled: May 29, 2003Publication date: November 6, 2003Applicant: Murata Manufacturing Co., Ltd.Inventor: Mitsutoshi Kawamoto
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Publication number: 20030143333Abstract: 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: ApplicationFiled: January 17, 2003Publication date: July 31, 2003Inventor: Mitsutoshi Kawamoto
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Patent number: 6544443Abstract: 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: GrantFiled: December 5, 2000Date of Patent: April 8, 2003Assignee: Murata Manufacturing Co., Ltd.Inventors: Hideaki Niimi, Akira Ando, Mitsutoshi Kawamoto, Masahiro Kodama
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Patent number: 6542067Abstract: 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: GrantFiled: May 22, 2000Date of Patent: April 1, 2003Assignee: Murata Manufacturing Co., Ltd.Inventor: Mitsutoshi Kawamoto
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Publication number: 20030030192Abstract: 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: ApplicationFiled: September 18, 2002Publication date: February 13, 2003Applicant: Murata Manufacturing Co., Ltd.Inventors: Hideaki Niimi, Akira Ando, Mitsutoshi Kawamoto, Masahiro Kodama
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Publication number: 20030022784Abstract: 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: ApplicationFiled: September 13, 2002Publication date: January 30, 2003Applicant: Murata Manufacturing Co., Ltd.Inventors: Mitsutoshi Kawamoto, Hideaki Niimi, Ryouichi Urahara, Yukio Sakabe
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Patent number: 6472339Abstract: 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: GrantFiled: September 18, 1998Date of Patent: October 29, 2002Assignee: Murata Manufacturing Co., Ltd.Inventors: Mitsutoshi Kawamoto, Hideaki Niimi, Ryouichi Urahara, Yukio Sakabe
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Publication number: 20020130318Abstract: 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: ApplicationFiled: December 18, 2001Publication date: September 19, 2002Applicant: Murata Manufacturing Co., Ltd.Inventors: Masahiro Kodama, Atsushi Kishimoto, Mitsutoshi Kawamoto, Hideaki Niimi, Akira Ando
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Publication number: 20020105022Abstract: 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: ApplicationFiled: December 11, 2000Publication date: August 8, 2002Applicant: Murata Manufacturing Co., LtdInventors: Mitsutoshi Kawamoto, Hideaki Niimi, Masahiro Kodama, Atsushi Kishimoto
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Patent number: 6376079Abstract: 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: GrantFiled: March 30, 1999Date of Patent: April 23, 2002Assignee: Murata Manufacturing Co., Ltd.Inventors: Mitsutoshi Kawamoto, Hideaki Niimi
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Publication number: 20010008866Abstract: 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: ApplicationFiled: September 18, 1998Publication date: July 19, 2001Inventors: MITSUTOSHI KAWAMOTO, HIDEAKI NIIMI, RYOUICHI URAHARA, YUKIO SAKABE
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Publication number: 20010003361Abstract: 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: ApplicationFiled: December 5, 2000Publication date: June 14, 2001Applicant: Murata Manufacturing Co., Ltd.Inventors: Hideaki Niimi, Akira Ando, Mitsutoshi Kawamoto, Masahiro Kodama
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Patent number: 6162752Abstract: 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: GrantFiled: May 11, 1999Date of Patent: December 19, 2000Assignee: Murata Manufacturing Co., Ltd.Inventors: Mitsutoshi Kawamoto, Hideaki Niimi
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Patent number: 6153931Abstract: 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: GrantFiled: March 4, 1999Date of Patent: November 28, 2000Assignee: Murata Manufacturing Co., Ltd.Inventors: Hideaki Niimi, Mitsutoshi Kawamoto, Akinori Nakayama, Satoshi Ueno, Ryouichi Urahara
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Patent number: 5733832Abstract: 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: GrantFiled: January 27, 1997Date of Patent: March 31, 1998Assignee: Murata Manufacturing Co., Ltd.Inventors: Mitsutoshi Kawamoto, Yukio Hamaji