Patents by Inventor Munemitsu Hamada
Munemitsu Hamada 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: 6432325Abstract: 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: GrantFiled: March 2, 2000Date of Patent: August 13, 2002Assignee: TDK CorporationInventors: Munemitsu Hamada, Akira Takeishi, Makoto Takahashi, Dai Matsuoka, Masatada Yodogawa, Hiraku Harada
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Patent number: 6383416Abstract: 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: GrantFiled: March 2, 2000Date of Patent: May 7, 2002Assignee: TDK CorporationInventors: Munemitsu Hamada, Akira Takeishi, Makoto Takahashi, Dai Matsuoka, Masatada Yodogawa, Hiraku Harada
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Patent number: 6172453Abstract: The present invention provides an electrode for a ceramic electrode fluorescent discharge lamp; an electrode material for a discharge lamp, which has high electron flow density, high thermal shock resistance, and reduced deterioration due to sputtering; and also a method for manufacturing the same. The invention makes it possible to reduce the tube diameter of the ceramic electrode fluorescent discharge lamp. An electrode material for a discharge lamp is obtained from a first component of 0.5 to 1.5 mols of BaO, CaO or SrO, a second component of 0.05 to less than 0.3 mols or more than 0.7 to 0.95 mols of ZrO2 or TiO2, and a third component of 0.025 to less than 0.3 mols of V2O5, Nb2O5, Ta2O5, Sc2O3, Y2O3, La2O3, Dy2O3, or Ho2O3, or 0.05 to less than 0.15 mols or more than 0.35 to 0.95 mols of HfO2, CrO3, MoO3 or WO3. This electrode material is granulated and is turned into a massive, granular, or porous electrode material.Type: GrantFiled: November 17, 1994Date of Patent: January 9, 2001Assignee: TDK CorporationInventors: Munemitsu Hamada, Masaru Fukuda, Haruo Taguchi, Shoichi Iwaya, Hiroaki Abe
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Patent number: 5982088Abstract: A ceramic cathode fluorescent discharge lamp is provided including a pair of electrodes, a bulb plated with a fluorescent body on an inner surface of same, at least one of said pair of electrodes being a ceramic cathode having a bottomed cylindrical housing including an electron emission material of an aggregate type porous structure of conductive oxide having a first component consisting of at least one of Ba, Sr, and Ca, a second component consisting of at least one of Zr and Ti, and a third component consisting of at least one of Ta and Nb, said aggregate type porous structure having a surface plated with a conductive or semiconductive layer of at least one of carbide, nitride and oxide of Ta or Nb, rare gas being sealed in said bulb, and sealing pressure of said rare gas being in the range between 10 Torr and 170 Torr.Type: GrantFiled: November 13, 1997Date of Patent: November 9, 1999Assignee: TDK CorporationInventors: Munemitsu Hamada, Akira Takeishi, Haruo Taguchi, Takeshi Masuda, Yasutoshi Yamaguchi
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Patent number: 5793276Abstract: An organic PTC thermistor having a positive temperature coefficient of resistivity, which comprises a PTC composition comprising an organic polymer having dispersed therein a conductive substance, and at least one pair of electrodes, wherein the conductive substance is tungsten carbide powder; or the electrodes each comprise a metal mesh and a metal layer.Type: GrantFiled: July 17, 1996Date of Patent: August 11, 1998Assignee: TDK CorporationInventors: Hisanao Tosaka, Minoru Takaya, Shigeru Moriya, Hisashi Kobuke, Munemitsu Hamada
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Patent number: 5091820Abstract: A ceramic piezoelectric, includes a thick core formed of a sintered ceramic material, and a pair of electrodes formed on opposing end faces of the core, wherein the electrodes are a reduced form of the ceramic material of the core. The electrodes may also be a reduced layer of an oxide formed on the ceramic material of the core.Type: GrantFiled: November 3, 1989Date of Patent: February 25, 1992Assignee: TDK CorporationInventors: Shouichi Iwaya, Munemitsu Hamada, Hitoshi Masumura
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Patent number: 5084426Abstract: A semiconductive ceramic composition capable of permitting its resistance-temperature characteristics and resistance to be controlled as desired and a firing temperature of the composition to be lowered to a degree sufficient to facilitate the mass-production at a low cost. The composition contains a main component consisting of SrO, PbO and TiO.sub.2 and is subjected to firing in an oxidizing atmosphere. The composition may contain at least one of SiO.sub.2 and M as a minor component. A variation in amount of the main and minor components permits characteristics and properties of the composition to be varied as desired.Type: GrantFiled: July 13, 1989Date of Patent: January 28, 1992Assignee: TDK CorporationInventors: Shoichi Iwaya, Hitoshi Masumura, Haruo Taguchi, Munemitsu Hamada, Tomohiro Sogabe, Shigeya Takahashi, Hiroyuki Satoh
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Patent number: 4987515Abstract: A ceramic capacitor, includes a thick core formed of a sintered ceramic material, and a pair of electrodes formed on opposing end faces of the core, wherein the electrodes are a reduced form of the ceramic material of the core. The electrodes may also be a reduced layer of an oxide formed on the ceramic material of the core.Type: GrantFiled: November 3, 1989Date of Patent: January 22, 1991Assignee: TDK CorporationInventors: Shouichi Iwaya, Munemitsu Hamada, Hitoshi Masumura
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Patent number: 4808883Abstract: A discharge lamp device includes a tube, and a cathode disposed in said tube and made of a valence-compensated semiconductor ceramic material, or a forcibly reduced semiconductor ceramic material, or a valence-compensated and forcibly reduced semiconductor ceramic material. Since the cathode does not include an electron-emitting material, but uses a semiconductor ceramic material, no vapor is produced by the cathode and also the cathode does not react with mercury vapor filled in the tube. Therefore, the discharge lamp device has improved characteristics such as greater heat resistance, better chemical resistance, and improved discharge characteristics. The discharge lamp device is less costly because the semiconductor ceramic material used as the cathode is inexpensive.Type: GrantFiled: March 22, 1988Date of Patent: February 28, 1989Assignee: TDK CorporationInventors: Shouichi Iwaya, Hitoshi Masumura, Munemitsu Hamada