Patents by Inventor Yasuo Wakahata
Yasuo Wakahata 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: 6260258Abstract: A method for manufacturing varistor by which a varistor having a high plating resistance and a high moisture resistance is manufactured by selectively forming a compact high-resistance layer having a uniform thickness on the surface of a varistor element. In the method, the varistor element (1) is first formed by alternately laminating ceramic sheets (1a) mainly of a zinc oxide and internal electrodes (2) upon one another, and then, Ag electrode paste which becomes external electrodes (3) is applied to both end faces of the element (1). Then, after the element (1) is sintered through heat treatment, the element (1) is buried in SiO2 or a mixture (5) containing SiO2 and the element (1) is heat-treated for 5-10 minutes at 600-950° C. in the air or in an oxygen atmosphere.Type: GrantFiled: November 10, 1998Date of Patent: July 17, 2001Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hideaki Tokunaga, Miho Higashitani, Yasuo Wakahata
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Patent number: 6090435Abstract: The electronic component of the present invention includes: an element having an internal electrode therein; an external electrode formed on an end portion of the element where an end face of the internal electrode is exposed; and a protection layer formed on the entire surface of the element except for the end portion of the element, wherein the protection layer is made of a metal oxide.Type: GrantFiled: September 15, 1998Date of Patent: July 18, 2000Assignee: Matsushita Electric Industrial Co., LtdInventors: Iwao Ueno, Yasuo Wakahata
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Patent number: 6027338Abstract: A furnace for manufacturing ceramics is disclosed. The furnace contains a cylindrical heat resistant container, a furnace body for heating the cylindrical heat resistant container, and driving means for driving the cylindrical heat resistant container. The cylindrical heat resistant container rotates about a central shaft. At the same time, a first end and alternately a second end of the cylindrical heat resistant container are raised and lowered periodically, thus creating a seesaw motion while any material contained in the cylindrical heat resistant container is fired by the furnace body.Type: GrantFiled: October 22, 1997Date of Patent: February 22, 2000Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hideyuki Okinaka, Yasuo Wakahata, Toru Fukada
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Patent number: 5866196Abstract: The electronic component of the present invention includes: an element having an internal electrode therein; an external electrode formed on an end portion of the element where an end face of the internal electrode is exposed; and a protection layer formed on the entire surface of the element except for the end portion of the element, wherein the protection layer is made of a metal oxide.Type: GrantFiled: March 6, 1997Date of Patent: February 2, 1999Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Iwao Ueno, Yasuo Wakahata
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Patent number: 5762862Abstract: The invention is directed to a method of firing ceramics and a furnace for manufacturing ceramics. Ceramic forms are first fired in a cylindrical heat resistant container in a furnace core tube by using a lateral tubular furnace to increase their mechanical strength. Then, the container is rotated while the ceramic forms are fired further in a predetermined temperature region, which includes a maximum temperature. In this manner the ceramic forms are heated in a uniform state, both thermally and atmospherically, while receiving moderate impact by rotation, and defective appearance and fluctuations in the characteristics of the ceramics are suppressed. In particular, the container is rotated within a temperature region which is higher than the temperature used to start increasing the mechanical strength of the ceramic forms. Further, the ceramic forms can be packed into the container at a higher rate during the rotation portion of the process than during the first firing.Type: GrantFiled: November 7, 1996Date of Patent: June 9, 1998Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hideyuki Okinaka, Yasuo Wakahata, Toru Fukada
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Patent number: 5750264Abstract: The electronic component of the present invention includes: an element having an internal electrode therein; an external electrode formed on an end portion of the element where an end face of the internal electrode is exposed; and a protection layer formed on the entire surface of the element except for the end portion of the element, wherein the protection layer is made of a metal oxide.Type: GrantFiled: October 16, 1995Date of Patent: May 12, 1998Assignee: Matsushita Electric Industrial Co., Inc.Inventors: Iwao Ueno, Yasuo Wakahata
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Patent number: 5592140Abstract: The varistor element contains zinc-oxide as a main constituent and at least bismuth and antimony as accessory constituents. The content of bismuth in the form of Bi.sub.2 O.sub.3 is in a range from about 0.1 to 4.0 mol % and the content of antimony in the form of Sb.sub.2 O.sub.3 constitutes a mol-ratio of Sb.sub.2 O.sub.3 /Bi.sub.2 O.sub.3 less than or equal to about 1.0 mol %. These materials are mixed thoroughly and are pressed into a compact. After coating both sides of the compact with Ag or Ag--Pd paste, the compact and its electrodes are sintered simultaneously at a temperature of about 800.degree. C. to 960.degree. C.Type: GrantFiled: September 29, 1994Date of Patent: January 7, 1997Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hideaki Tokunaga, Yasuo Wakahata, Naoki Mutoh
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Patent number: 5520759Abstract: The present invention relates to a method for manufacture of ceramic parts used for protecting semiconductor devices such as IC, LSI, etc. against anomalous high voltages such as noise, pulse, static electricity, etc. and the object of the present invention is to provide ceramic parts capable of removing or restraining high-frequency noises on signal lines by reducing the impedance of the devices.In order to attain the above object, according to the present invention, a pulse voltage of 50 kV in maximum value which requires a time of 200 nanoseconds or less for reaching the maximum value from an initial value and a time of 1 microsecond or less for returning to the initial value through the maximum value and which has an energy of 0.5 joule or lower is applied at least once between the electrodes (2).Type: GrantFiled: April 20, 1994Date of Patent: May 28, 1996Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Keiichi Noi, Iwao Ueno, Yoichi Ogoshi, Yasuo Wakahata
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Patent number: 5268006Abstract: A method for manufacturing semiconductor-type laminated ceramic capacitors with a grain boundary-insulated structure including the steps of calcinating starting material of mixed powder in air or in nitrogen atmosphere after grinding, mixing and drying the mixed powder; forming raw sheets; printing a pattern of inner electrode paste on the surface of the raw sheets; calcinating the laminated body in air; sintering the laminated raw sheets in reducing atmosphere or in nitrogen atmosphere after calcination; re-oxidizing in air after sintering; and covering the edges of sintered ceramic sheets with outer electrode paste and baking after re-oxidation, terminals of inner electrodes being exposed to the edges, wherein: the starting material of mixed powder comprises a material of the composition Sr.sub.(1-x) Ba.sub.x TiO.sub.3 containing excess Ti to make a final molecular ratio of Ti to Sr.sub.(1-x) Ba.sub.x in the range of 0.95.ltoreq. Sr.sub.(1-x)Ba.sub.x /Ti< 1.00 (where x is in the range of 0< x.ltoreq.Type: GrantFiled: July 28, 1992Date of Patent: December 7, 1993Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Iwao Ueno, Yasuo Wakahata, Kimio Kobayashi, Kaori Okamoto, Akihiro Takami
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Patent number: 5208727Abstract: The present invention provides a semiconductor-type laminated ceramic capacitor with a grain boundary-insulated structure made of Sr.sub.(1-x) Ca.sub.x TiO.sub.3 as a main component, comprising the functions of a conventional capacitor which absorbs low voltage noises and high frequency noises, and a varistor when high voltage noises and electrostatic charges invade, wherein simultaneous sintering of the materials of ceramic capacitor together with the materials of inner electrodes was made possible in the manufacturing process. Besides, material to be made semiconductive is added to the main component of Sr.sub.(1-x) Ca.sub.x TiO.sub.3 excess in Ti, the materials of Mn-Si, which are converted to MnO.sub.2 and SiO.sub.2 in the sintering process, are also added to the main component.Type: GrantFiled: August 5, 1991Date of Patent: May 4, 1993Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Kaori Okamoto, Yasuo Wakahata, Iwao Ueno
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Patent number: 5166759Abstract: The present invention provides a semiconductor-type laminated ceramic capacitor with a grain boundary-insulated structure made of Sr.sub.(1-x) Ba.sub.x TiO.sub.3 as a main component, comprising the functions of a conventional capacitor which absorbs low voltage noises and high frequency noises, and a varistor when high voltage noises and electrostatic charges invade, wherein simultaneous sintering of the materials of ceramic capacitor together with the materials of inner electrodes was made possible in the manufacturing process. Besides a material to be made semiconductive is added to the main component of Sr.sub.(1-x) Ba.sub.x TiO.sub.3 with excess Ti, the materials of Mn-Si, which are converted to MnO.sub.2 and SiO.sub.2 in the sintering process, are also added to the main component.Type: GrantFiled: September 28, 1990Date of Patent: November 24, 1992Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Iwao Ueno, Yasuo Wakahata, Kimio Kobayashi, Kaori Shiraishi, Akihiro Takami
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Patent number: 5166859Abstract: A laminated semiconductor ceramic capacitor with a grain boundary-insulated structure comprises a semiconductor ceramic block with a grain boundary-insulated structure, a plurality of Ni inner electrodes and outer electrodes, wherein the Ni inner electrodes are obtained from a paste containing a powder prepared by solubilizing at least one compound containing an atom selected from the group consisting of Li, Na and K into Ni or an Ni containing compound; the Ni inner electrodes are placed in a substantially parallel manner within the ceramic block to reach to the corresponding opposite edges of the ceramic block alternatively one by one; and the outer electrodes are electrically connected to the corresponding edges of the inner electrodes, respectively.Type: GrantFiled: December 20, 1991Date of Patent: November 24, 1992Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Iwao Ueno, Yasuo Wakahata, Kimio Kobayashi, Kaori Shiraishi, Akihiro Takami, Youichi Ogoshi
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Patent number: 5075818Abstract: A semiconductor-type laminated ceramic capacitor with a grain boundary-insulated structure made of SrTiO.sub.3 as the main component, comprising the functions of a conventional capacitor which absorbs low voltage noises and high frequency noises, and a varistor when high voltage noises and electrostatic charges invade, wherein simultaneous sintering of the materials of the ceramic capacitor together with the materials of inner electrodes has been made possible in the manufacturing process. A material to be made semiconducting is added to the main component of SrTiO.sub.3 with an excess in Ti, the materials of Mn--Si, which are converted to MnO.sub.2 and SiO.sub.2 in the sintering process are also added to the main component.Type: GrantFiled: September 28, 1990Date of Patent: December 24, 1991Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Iwao Ueno, Yasuo Wakahata, Kimio Kobayashi, Kaori Okamoto, Akihiro Takami
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Patent number: 4874227Abstract: A large number of liquid crystal display devices is formed on a single plane, each of the liquid crystal display devices being formed by arranging liquid crystal between transparent substrates which allow light from a light source to pass through. Display portions of the respective liquid crystal display devices are covered by a masking member (23) and a light guide which is formed of light guide devices, one or more of which being provided for each of said liquid crystal display devices, and junctions between the liquid crystal display devices are also covered by the light guide. With this structure, when the light guides are formed such that the junctions between the plurality of liquid crystal display devices are also covered, lattice-like non-display lines do not appear, thereby providing substantially visually uniform brightness throughout the entire screen of the large-sized liquid crystal display and improving the entire image.Type: GrantFiled: February 9, 1988Date of Patent: October 17, 1989Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hideki Matsukawa, Takeshi Masuyama, Minoru Hirota, Yasuo Wakahata, Masahiro Itoh, Shinji Harada
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Patent number: 4490015Abstract: The present invention provides a liquid crystal color display panel of improved positive contrast by utilizing the so-called Guest-Host effect.Type: GrantFiled: May 25, 1982Date of Patent: December 25, 1984Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Hiroshi Kawarada, Toshio Tatsumichi, Yasuo Wakahata, Mitsuyoshi Hamanaka, Tamotsu Kajitani
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Patent number: 4428909Abstract: The present invention relates to an environmental condition sensor which is used to detect temperature etc., which sensor comprises an environmental condition sensor proper (1, 3,or 7), and a gas permeable structure (2 or 5) comprising .gamma.-MnO.sub.2, (Zn--Mn--FeO.sub.x) , and mAl.sub.2 O.sub.3.nCaO as the main composition thereof or an enamel layer (9) comprising .gamma.-MnO.sub.2, (Zn--Mn--FeOx), (.alpha.-Al.sub.2 O.sub.3.zeorite), and frit as the main composition thereof, which structure or layer surrounds the environmental condition sensor proper, so that carbon in oily smake and uncombustion gas striking the structure burns to prevent the oily smake and carbon from adhering to the environmental condition sensor proper (1, 3 or 7), whereby the degradation of the characteristics of the environmental condition sensor proper is avoided.Type: GrantFiled: August 19, 1981Date of Patent: January 31, 1984Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Tomohiro Yashiki, Fumio Hosomi, Yasuo Wakahata, Atsushi Nishino, Kiyotaka Wasa, Masazumi Katase
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Patent number: 4045374Abstract: A voltage-dependent resistor (varistor) of the bulk type comprising a sintered body consisting essentially of, as a main constituent, ZnO and additives of various metal oxides and further containing an additive of at least one of Al.sub.2 O.sub.3, In.sub.2 O.sub.3 Ga.sub.2 O.sub.3 provide much improved characteristics, especially superior limiting voltage ratio, surge resistance and life of the varistor.Type: GrantFiled: October 10, 1975Date of Patent: August 30, 1977Assignee: Matsushita Electric Industrial Co., Ltd.Inventors: Masahiro Nagasawa, Yasuo Wakahata, Kensuke Kuchiba, Kunio Nishi, Hiroshi Abe