Patents by Inventor Yasuhiro Nabika
Yasuhiro Nabika 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: 9530547Abstract: A laminated PTC thermistor element that includes a ceramic substrate including a plurality of ceramic layers, a plurality of internal electrodes within the ceramic substrate, and external electrodes on the surface of the ceramic substrate that provide electrical conduction to the internal electrodes. The ceramic substrate is 0.3 [?m] or more and 1.2 [?m] or less in average porcelain grain size. Furthermore, the relative density of the ceramic substrate has a lower limit of 70 [%], and an upper limit of ?6.43d+97.83 [%] when the average porcelain grain size is denoted by d.Type: GrantFiled: December 10, 2014Date of Patent: December 27, 2016Assignee: MURATA MANUFACTURING CO., LTD.Inventors: Wataru Aoto, Yumin Saigo, Hayato Katsu, Yasuhiro Nabika
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Publication number: 20150091690Abstract: A laminated PTC thermistor element that includes a ceramic substrate including a plurality of ceramic layers, a plurality of internal electrodes within the ceramic substrate, and external electrodes on the surface of the ceramic substrate that provide electrical conduction to the internal electrodes. The ceramic substrate is 0.3 [?m] or more and 1.2 [?m] or less in average porcelain grain size. Furthermore, the relative density of the ceramic substrate has a lower limit of 70 [%], and an upper limit of ?6.43d+97.83 [%] when the average porcelain grain size is denoted by d.Type: ApplicationFiled: December 10, 2014Publication date: April 2, 2015Inventors: Wataru Aoto, Yumin Saigo, Hayato Katsu, Yasuhiro Nabika
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Publication number: 20140247107Abstract: A barium titanate semiconductor ceramic with positive resistance-temperature characteristics, which is represented by the general formula: BaTiO3, wherein a Ti site is partially substituted with Zr, and a content ratio of Zr falls within the range of 0.14 to 0.88 mol %, and a PTC thermistor using the same.Type: ApplicationFiled: April 23, 2014Publication date: September 4, 2014Applicant: MURATA MANUFACTURING CO., LTD.Inventors: Wataru Aoto, Hayato Katsu, Yasuhiro Nabika
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Patent number: 8187506Abstract: A barium titanate-based semiconductor ceramic composition which can be used for PTC thermistors for temperature sensors and which has characteristics, including a linear characteristic, advantageous for such PTC thermistors and a barium titanate-based semiconductor ceramic device. The barium titanate-based semiconductor ceramic composition is represented by the formula (Ba(1-v-w)MevSrw)TixO3+ySiO2, wherein Me is at least one of Er, Sm, Ce, and La, 0.001?v?0.005, 0.42?w?0.49, 0.99?x?1.03, and 0.002?y?0.030.Type: GrantFiled: November 23, 2011Date of Patent: May 29, 2012Assignee: Murata Manufacturing Co., Ltd.Inventors: Yoichi Kawase, Syunsuke Okuda, Yuichi Hirata, Yasuhiro Nabika
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Publication number: 20120068127Abstract: A barium titanate-based semiconductor ceramic composition which can be used for PTC thermistors for temperature sensors and which has characteristics, including a linear characteristic, advantageous for such PTC thermistors and a barium titanate-based semiconductor ceramic device. The barium titanate-based semiconductor ceramic composition is represented by the formula (Ba(1?v?w)MevSrw)TixO3+ySiO2, wherein Me is at least one of Er, Sm, Ce, and La, 0.001?v?0.005, 0.42?w?0.49, 0.99?x?1.03, and 0.002?y?0.030.Type: ApplicationFiled: November 23, 2011Publication date: March 22, 2012Applicant: MURATA MANUFACTURING CO., LTD.Inventors: Yoichi Kawase, Syunsuke Okuda, Yuichi Hirata, Yasuhiro Nabika
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Publication number: 20040027229Abstract: In a semiconductive ceramic which has a positive resistance temperature characteristic and is used as a degaussing thermistor element, the current attenuation characteristic is slowly changed without increasing the size of the element by setting a resistance temperature coefficient &agr; in the range of from about 10 to 17.Type: ApplicationFiled: May 30, 2003Publication date: February 12, 2004Inventors: Yasuhiro Nabika, Mitsugu Takada, Hiroki Tanaka, Yoshinori Kitamura
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Patent number: 6522238Abstract: A semiconductor ceramic contains erbium as a semiconducting agent in primary components of barium titanate, strontium titanate, lead titanate and calcium titanate, with the average grain diameter of the semiconductor ceramic exceeding about 5 &mgr;m but not exceeding about 14 &mgr;m. Further, the semiconductor ceramic contains as additives a compound containing Er with the Er being more than about 0.10 mol but no more than about 0.33 mol, a compound containing Mn with the Mn being about 0.01 mol or more but no more than about 0.03 mol, and a compound containing Si with the Si being about 1.0 mol or more but no more than about 5.0 mol, per 100 mol of the primary component. Thus, a semiconductor ceramic and positive-temperature-coefficient thermistor can be provided with high-flash-breakdown capability, excellent results in ON-OFF application tests and few irregularities in resistance values.Type: GrantFiled: July 11, 2001Date of Patent: February 18, 2003Assignee: Murata Manufacturing Co. Ltd.Inventors: Yoshitaka Nagao, Yasuhiro Nabika, Toshiharu Hirota
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Patent number: 6455454Abstract: Provided is a semiconductor ceramic and a semiconductor ceramic element each having a room temperature specific resistance of 3 &OHgr;·cm or lower and a resistance temperature characteristic of 9%/° C. or more. The semiconductor ceramic is characterized in that the ratio R1/(R1+R2), in which R1 is the transgranular resistance value of the crystal particles and R2 is the intergranular resistance value of the crystal particles and R1+R2 is the overall resistance value representing the sum of R1 and R2, is about 0.35 to 0.85.Type: GrantFiled: April 28, 2000Date of Patent: September 24, 2002Assignee: Murata Manufacturing Co. Ltd.Inventors: Yasuhiro Nabika, Tetsukazu Okamoto, Toshiharu Hirota
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Patent number: 6432558Abstract: A semiconductor ceramic device comprises a body composed of a semiconductor ceramic having a positive resistance-temperature coefficient primarily composed of barium titanate and electrodes provided on the body, in which the resistance-temperature coefficient is 9%/° C. or more, resistivity is 3.5 ∩·cm or less, and withstand voltage is 50 V/mm or more. As the semiconductor ceramic forming the body provided in a thermistor having positive resistance-temperature characteristics, a semiconductor ceramic having a positive resistance-temperature coefficient is used, in which the semiconductor ceramic has an average particle diameter of about 7 to 12 &mgr;m and comprises barium titanate as a major component and sodium in an amount of about 70 ppm or less on a weight basis.Type: GrantFiled: August 8, 2000Date of Patent: August 13, 2002Assignee: Murata Manufacturing Co. Ltd.Inventors: Yasuhiro Nabika, Tetsukazu Okamoto, Toshiharu Hirota, Yoshitaka Nagao
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Patent number: 6362521Abstract: A semiconductor ceramic composed of barium titanate, lead titanate, strontium titanate, and calcium titanate as primary components, includes samarium oxide as a semiconductor-forming agent in the primary components, and the average diameter of crystalline particles of the semiconductor ceramic is about 7 to 12 &mgr;m. The semiconductor ceramic has a resistivity at room temperature not greater than 3.5 &OHgr;cm, a withstand voltage not less than 50 V/mm, a resistance-temperature coefficient &agr;10-100 not less than 9%/°C. and also has less variability of resistance.Type: GrantFiled: October 27, 1999Date of Patent: March 26, 2002Assignee: Murata Manufacturing Co., Ltd.Inventors: Yasuhiro Nabika, Tetsukazu Okamoto, Toshiharu Hirota, Noriyuki Yamamoto
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Publication number: 20020027492Abstract: A semiconductor ceramic contains erbium as a semiconducting agent in primary components of barium titanate, strontium titanate, lead titanate and calcium titanate, with the average grain diameter of the semiconductor ceramic exceeding about 5 &mgr;m but not exceeding about 14 &mgr;m. Further, the semiconductor ceramic contains as additives a compound containing Er with the Er being more than about 0.10 mol but no more than about 0.33 mol, a compound containing Mn with the Mn being about 0.01 mol or more but no more than about 0.03 mol, and a compound containing Si with the Si being about 1.0 mol or more but no more than about 5.0 mol, per 100 mol of the primary component. Thus, a semiconductor ceramic and positive-temperature-coefficient thermistor can be provided with high-flash-breakdown capability, excellent results in ON-OFF application tests and few irregularities in resistance values.Type: ApplicationFiled: July 11, 2001Publication date: March 7, 2002Applicant: Murata manufacturing Co., Ltd.Inventors: Yoshitaka Nagao, Yasuhiro Nabika, Toshiharu Hirota
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Patent number: 6346496Abstract: A ceramic for the PTC thermistor having a resistivity at room temperature of 5 &OHgr;·cm or less, static withstanding voltage of 60 V/mm or more and temperature resistance coefficient of 9.0 %/° C., having small dispersion of the resistance, is composed of principal components of about 30 to 97 mol % of BaTiO3, about 1 to 50 mol % of PbTiO3, about 1 to 30 mol % of SrTiO3 and about 1 to 25 mol % of CaTiO3 (the total content of them being 100 mol %), as well as about 0.1 to 0.3 mole of Sm, about 0.01 to 0.03 mole of Mn and 0 to about 2.0 mole of Si relative to 100 moles of the principal components, the composite material being preferably heat-treated in an oxidative atmosphere after being fired in a reducing or neutral atmosphere for obtaining the ceramic.Type: GrantFiled: July 23, 1999Date of Patent: February 12, 2002Assignee: Murata Manufacturing Co., Ltd.Inventors: Yasuhiro Nabika, Tetsukazu Okamoto, Toshiharu Hirota, Noriyuki Yamamoto
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Publication number: 20010008867Abstract: A ceramic for the PTC thermistor having a resistivity at room temperature of 5 &OHgr;·cm or less, static withstanding voltage of 60 V/mm or more and temperature resistance coefficient of 9.0%/° C., having small dispersion of the resistance, is composed of principal components of about 30 to 97 mol % of BaTiO3, about 1 to 50 mol % of PbTiO3, about 1 to 30 mol % of SrTiO3 and about 1 to 25 mol % of CaTiO3 (the total content of them being 100 mol %), as well as about 0.1 to 0.3 mole of Sm, about 0.01 to 0.03 mole of Mn and 0 to about 2.0 mole of Si relative to 100 moles of the principal components, the composite material being preferably heat-treated in an oxidative atmosphere after being fired in a reducing or neutral atmosphere for obtaining the ceramic.Type: ApplicationFiled: July 23, 1999Publication date: July 19, 2001Inventors: YASUHIRO NABIKA, TETSUKAZU OKAMOTO, TOSHIHARU HIROTA, NORIYUKI YAMAMOTO
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Patent number: 6187707Abstract: A barium titanate-based semiconductive ceramic composition for facilitating miniaturization of thermistor devices by improving rush current resistance characteristics is provided. In the barium titanate-based semiconductive ceramic composition, a fraction of the Ba in BaTiO3 as the major component is replaced with 1 to 25 mole percent of Ca, 1 to 30 mole percent of Sr, and 1 to 50 mole percent of Pb; and wherein to 100 mole percent of the major component, the semiconductivity-imparting agent is added in an amount of 0.2 to 1.0 mole percent as a converted element content, and the additive comprises manganese oxide in an amount of 0.01 to 0.10 mole percent as a converted Mn content, silica in an amount of 0.5 to 5 mole percent as a converted SiO2 content, and magnesium oxide in an amount of 0.028 to 0.093 mole percent as a converted Mg content.Type: GrantFiled: May 20, 1999Date of Patent: February 13, 2001Assignee: Murata Manufacturing Co., Ltd.Inventors: Satoshi Kakihara, Toshiharu Hirota, Yasuhiro Nabika, Noriyuki Yamamoto
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Patent number: 6133821Abstract: A PTC thermistor has a disk-shaped main body with electrodes on its main surfaces which are facing mutually away from each other such that, during an initial period after a potential difference is applied between these electrodes, the side surface of the main body has an asymmetric temperature distribution between the electrodes in the direction normal to its main surfaces. The heat emission does not have a peak half-way between the electrodes in the direction of the thickness such that the thermistor has an improved resistance against flash pressure. This may be done by forming the electrodes in different sizes or by providing a non-uniform distribution in specific resistance to the main body such that the heat-emission peak is displaced from the center region between the two main surfaces of the main body.Type: GrantFiled: October 13, 1998Date of Patent: October 17, 2000Assignee: Murata Manufacturing Co., Ltd.Inventors: Yasuhiro Nabika, Takeo Haga
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Patent number: 5939972Abstract: A thermistor element with positive temperature characteristic (PTC) has a planar ceramic member with a positive temperature characteristic of which the thickness is greater at its peripheral part than at the center part, decreasing either gradually or in a stepwise manner. Protrusions may be formed along its periphery. A PTC thermistor is formed with electrodes formed on both main surfaces of such a PTC thermistor, each electrode having a lower-layer electrode all over a main surface and an upper-layer electrode on the lower-layer electrode. The upper-layer electrode has a smaller surface area than the lower-layer electrode such that a portion of the lower-surface electrode is exposed at the periphery. The upper-layer electrodes may be formed at the center parts of the main surfaces, exclusive of the peripheral parts or where the protrusions are formed. The lower-layer electrodes may be mostly of Ni and the upper-layer electrodes mainly of Ag.Type: GrantFiled: May 15, 1997Date of Patent: August 17, 1999Assignee: Murata Manufacturing Co., Ltd.Inventors: Yoshitaka Nagao, Toshiharu Hirota, Yasuhiro Nabika
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Patent number: 5733833Abstract: A semiconducting ceramic whose rush breakdown voltage is high and which hardly cracks during lamination is provided. In the semiconducting ceramic having a positive resistance-temperature characteristic, the ratio of intra-granular resistance of the crystal grains and inter-granular resistance between crystal grains which together determine the value of resistance of the semiconducting ceramic is set so that the intra-granular resistance is less than about 20% of the value of resistance of the semiconducting ceramic (not including 0%).Type: GrantFiled: December 27, 1996Date of Patent: March 31, 1998Assignee: Murata Manufacturing Co., Ltd.Inventors: Yoshiaki Abe, Takahiko Kawahara, Yasuhiro Nabika, Norimitsu Kito, Ryoichi Urahara