Patents by Inventor Hideaki Niimi

Hideaki Niimi 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).

  • Publication number: 20040189437
    Abstract: A positive temperature coefficient thermistor has a non-heating portion which is not heated when a voltage is applied between first and second internal electrodes. The non-heating portion is provided in the approximate center of the positive temperature coefficient thermistor and is arranged to extend along a direction that is substantially perpendicular to a lamination direction of the positive temperature coefficient thermistor. The non-heating portion is arranged at least in the approximate center in the lamination direction of the portion of the laminate where the first and the second internal electrodes are arranged. Thus, a hot spot is reliably prevented from occurring inside the laminate when voltage is applied. As a result, the withstand voltage property is greatly improved. The non-heating portion may include a cavity provided in at least one thermistor layer or an opening or cut portion provided in the internal electrode.
    Type: Application
    Filed: March 16, 2004
    Publication date: September 30, 2004
    Applicant: Murata Manufacturing Co., Ltd
    Inventors: Kenjiro Mihara, Hideaki Niimi
  • Patent number: 6791163
    Abstract: A chip electronic component including a ceramic element and terminal electrodes with metal coating thereon formed on the surface of the ceramic element. A glass layer is formed on a part of the surface of the ceramic element where the terminal electrodes are not formed. A glass material for the glass layer contains at least two species of alkali metal elements selected from Li, Na and K, and the total amount of the alkali metal elements is greater than or equal to 20 atomic percent of the total amount of elements except oxygen contained in the glass material.
    Type: Grant
    Filed: September 9, 2003
    Date of Patent: September 14, 2004
    Assignee: Murata Manufacturing Co. Ltd.
    Inventors: Atsushi Kishimoto, Hideaki Niimi, Akira Ando
  • Publication number: 20040140595
    Abstract: A multilayer thermistor with a positive temperature coefficient is manufactured by step 41 of forming a green laminate having thermistor green layers and internal electrode layers, step 42 of heat-treating this laminate at a temperature in the range of from 80 to less than 300° C., step 43 of performing dry-barrel polishing for the heat-treated green laminate, step 44 of forming external electrode films on respective end surfaces of this laminate, and step 45 of firing this laminate together with the individual electrode films. According to this method, a highly reliable multilayer thermistor with a positive temperature coefficient can be stably manufactured.
    Type: Application
    Filed: November 6, 2003
    Publication date: July 22, 2004
    Inventors: Kenjiro Mihara, Atsushi Kishimoto, Hideaki Niimi
  • Publication number: 20040084132
    Abstract: A laminated type semiconductor ceramic element is provided with good PTC characteristics, low room temperature resistance value and improved withstand voltage of 15V or higher. Semiconductor ceramic layers made from a semiconductor ceramic containing barium titanate as the main component and the element nickel at about 0.2 mol % or less (excluding 0 mol %), and internal electrode layers are superimposed alternately, and an external electrode is formed so as to be connected electrically with the internal electrode layers. The production method comprises the steps of obtaining a laminated product of semiconductor material layers containing a barium titanate as the main component and about 0.
    Type: Application
    Filed: October 27, 2003
    Publication date: May 6, 2004
    Applicant: Murata Manufacturing Co., Ltd.
    Inventor: Hideaki Niimi
  • Publication number: 20040048052
    Abstract: A chip electronic component including a ceramic element and terminal electrodes with metal coating thereon formed on the surface of the ceramic element. A glass layer is formed on a part of the surface of the ceramic element where the terminal electrodes are not formed. A glass material for the glass layer contains at least two species of alkali metal elements selected from Li, Na and K, and the total amount of the alkali metal elements is greater than or equal to 20 atomic percent of the total amount of elements except oxygen contained in the glass material.
    Type: Application
    Filed: September 9, 2003
    Publication date: March 11, 2004
    Inventors: Atsushi Kishimoto, Hideaki Niimi, Akira Ando
  • Publication number: 20040033629
    Abstract: A method of producing a laminated PTC thermistor involves alternately laminating electroconductive pastes to form internal electrodes and ceramic green sheets to form semiconductor ceramic layers with a positive resistance-temperature characteristic to form a laminate, firing the laminate to form a ceramic piece, and forming external electrodes on both of the end-faces of the ceramic piece, and heat-treating the ceramic piece having the external electrodes formed thereon at a temperature between about 60° C. and 200° C.
    Type: Application
    Filed: August 13, 2003
    Publication date: February 19, 2004
    Inventors: Kenjirou Mihara, Atsushi Kishimoto, Hideaki Niimi
  • 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: 6538318
    Abstract: A semiconductor ceramic for thermistors contains zinc oxide and titanium oxide as main components and a predetermined content of manganese. Also, a chip-type thermistor including the semiconductor ceramic is provided. By adding manganese, the resistance-temperature characteristic is controllable in the range of positive temperature coefficient to negative temperature coefficient. Also, by adding nickel, the resistivity is controllable. As a result, a thermistor material which provides a series of semiconductor ceramics having various resistivities and various B constants in a low range, for example 0 to 1,000 K, is available.
    Type: Grant
    Filed: December 14, 2001
    Date of Patent: March 25, 2003
    Assignee: Murata Manufacturing, Co., Ltd.
    Inventors: Kenji Nagareda, Kenjirou Mihara, Hideaki Niimi, Yuichi Takaoka
  • 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: 20020121696
    Abstract: A semiconductor ceramic for thermistors contains zinc oxide and titanium oxide as main components and a predetermined content of manganese. Also, a chip-type thermistor including the semiconductor ceramic is provided. By adding manganese, the resistance-temperature characteristic is controllable in the range of positive temperature coefficient to negative temperature coefficient. Also, by adding nickel, the resistivity is controllable. As a result, a thermistor material which provides a series of semiconductor ceramics having various resistivities and various B constants in a low range, for example 0 to 1,000 K, is available.
    Type: Application
    Filed: December 14, 2001
    Publication date: September 5, 2002
    Applicant: Murata Manufacturing Co., Ltd.
    Inventors: Kenji Nagareda, Kenjirou Mihara, Hideaki Niimi, Yuichi Takaoka
  • 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
  • Patent number: 6359327
    Abstract: A monolithic electronic element is fabricated from a semiconducting ceramic, which element can be produced through firing at 1000° C. or lower and exhibits a satisfactory PTC characteristic even when the element is produced through reoxidation at low temperature. The monolithic electronic element 1 includes a sintered laminate 3 formed of alternatingly stacked semiconducting ceramic layers 5 and internal electrode layers 7, and external electrodes 9 formed on the sintered laminate, wherein the semiconducting ceramic layers 5 comprise sintered barium titanate containing boron oxide; an oxide of at least one metal selected from among barium, strontium, calcium, lead, yttrium and a rare earth element; the boron oxide being incorporated in an amount, as reduced to atomic boron (B), satisfying the following relationships: 0.001≦B/&bgr;≦0.50 and 0.5≦B/(&agr;−&bgr;)≦10.
    Type: Grant
    Filed: March 1, 2000
    Date of Patent: March 19, 2002
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Hideaki Niimi, Tatsuya Matsunaga
  • Patent number: 6271538
    Abstract: A high-frequency detecting element that can detect a temperature increase in an instant due to high-frequency wave absorption using semiconducting ceramic with positive resistance-temperature characteristics. The ceramic is composed mainly of barium titanate. A high-frequency heater incorporating the high-frequency detecting element is also disclosed. In the high-frequency detecting element, electrodes are provided on one main surface of semiconducting ceramic 1 with positive resistance-temperature characteristics and leads 3a and 3b are soldered to the electrodes 2a and 2b.
    Type: Grant
    Filed: November 26, 1997
    Date of Patent: August 7, 2001
    Assignee: Murata Manufacturing Co., Ltd.
    Inventors: Hideaki Niimi, Yuichi Takaoka
  • 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: 20010003370
    Abstract: A high-frequency detecting element that can detect a temperature increase in an instant due to high-frequency wave absorption using semiconducting ceramic with positive resistance-temperature characteristics. The ceramic is composed mainly of barium titanate. A high-frequency heater incorporating the high-frequency detecting element is also disclosed. In the high-frequency detecting element, electrodes are provided on one main surface of semiconducting ceramic 1 with positive resistance-temperature characteristics and leads 3a and 3b are soldered to the electrodes 2a and 2b.
    Type: Application
    Filed: November 26, 1997
    Publication date: June 14, 2001
    Inventors: HIDEAKI NIIMI, YUICHI TAKAOKA
  • 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