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"Multilayer Ceramic Capacitor, Dielectric Ceramic, Multilayer Ceramic Electronic Component, and Method for Manufacturing Multilayer Ceramic...

February 6, 2014



"Multilayer Ceramic Capacitor, Dielectric Ceramic, Multilayer Ceramic Electronic Component, and Method for Manufacturing Multilayer Ceramic Capacitor" in Patent Application Approval Process

By a News Reporter-Staff News Editor at Politics & Government Week -- A patent application by the inventors Suzuki, Shoichiro (Nagaokakyo-shi, JP); Banno, Koichi (Nagaokakyo-shi, JP); Kanzaki, Taisuke (Nagaokakyo-shi, JP); Shiota, Akihiro (Nagaokakyo-shi, JP), filed on September 19, 2013, was made available online on January 23, 2014, according to news reporting originating from Washington, D.C., by VerticalNews correspondents.

This patent application is assigned to Murata Manufacturing Co., Ltd.

The following quote was obtained by the news editors from the background information supplied by the inventors: "With reference to FIG. 1, a multilayer ceramic capacitor 1, a representative example of a multilayer ceramic electronic component according to the present invention, will be described first.

"Multilayer ceramic capacitor 1 includes a multilayer body 2 which is formed from a plurality of laminated ceramic layers 3 and a plurality of internal electrodes 4 and 5 each formed along an interface between ceramic layers 3.

"A first external electrode 8 and a second external electrode 9 are formed at mutually different positions on an outer surface of multilayer body 2. In the multilayer ceramic capacitor 1 illustrated in FIG. 1, first external electrode 8 and second external electrode 9 are formed respectively on opposing end surfaces 6 and 7 of multilayer body 2. Internal electrode 4 includes a plurality of first internal electrodes 4 which are electrically connected to first external electrode 8 and internal electrode 5 includes a plurality of second internal electrodes 5 which are electrically connected to second external electrode 9. First internal electrodes 4 and second internal electrodes 5 are disposed alternately in the lamination direction. If necessary, a surface of external electrode 8 is coated with a first plating layer 10 and a second plating layer 12, and a surface of external electrode 9 is coated with a first plating layer 11 and a second plating layer 13.

"In recent years, a capacitor that has flat capacitance characteristics from a low temperature to a high temperature exceeding 150.degree. C. has been required, especially in the field of automobiles.

"Conventionally, a calcium titanate ceramic is known as such dielectric ceramic having the flat capacitance characteristics. For example, PTD 1 discloses a dielectric ceramic containing calcium titanate at 0 to 45%, Al.sub.2O.sub.3 and SiO.sub.2 at a total amount of 2 to 20%, at least one of MnO, Cr.sub.2O.sub.3, Fe.sub.2O.sub.3, CoO and NiO at a total amount of 0.1 to 1.0%, and the remainder being magnesium titanate at 50% or more."

In addition to the background information obtained for this patent application, VerticalNews journalists also obtained the inventors' summary information for this patent application: "Technical Problem

"The dielectric ceramic disclosed in PTD 1 has the problem of a low dielectric constant, notwithstanding the flat capacitance characteristics.

"The present invention has been accomplished in view of the aforementioned problem, and it is therefore an object of the present invention to provide a dielectric ceramic having flat capacitance characteristics and a high dielectric constant, and a multilayer ceramic electronic component using the dielectric ceramic.

"Solution to Problem

"A multilayer ceramic capacitor of the present invention includes a multilayer body having a plurality of laminated dielectric ceramic layers and a plurality of internal electrodes each formed along an interface between the dielectric ceramic layers, and a plurality of external electrodes formed on an outer surface of the multilayer body and electrically connected with the internal electrodes. The composition of the multilayer body includes any bismuth layered compound containing Sr, Bi and Ti, a bismuth layered compound containing Sr, Bi and Nb, and a bismuth layered compound containing Ca, Bi and Ti as a primary ingredient, Bi and at least one of Cu, Ba, Zn and Li, and satisfies such the condition that if the Ti content is 400 molar parts or the Nb content is 200 molar parts, then (Bi content-Ti content) or (Bi content-Nb content) is equal to or greater than 1 molar part and less than 7.5 molar parts and the total content of Cu, Ba, Zn and Li is equal to or greater than 1 molar part and less than 10 molar parts.

"A multilayer ceramic capacitor of the present invention includes a multilayer body having a plurality of laminated dielectric ceramic layers and a plurality of internal electrodes formed along an interface between the dielectric ceramic layers, and a plurality of external electrodes formed on an outer surface of the multilayer body and electrically connected with said internal electrodes. The composition of the multilayer body includes any bismuth layered compound containing Sr, Bi and Ti, a bismuth layered compound containing Sr, Bi and Nb, and a bismuth layered compound containing Ca, Bi and Ti as a primary ingredient, Bi and at least one of Cu, Ba, Zn and Li, and satisfies such the condition that if the Ti content is 400 molar parts or the Nb content is 200 molar parts when the multilayer body is dissolved in a solvent, then (Bi content-Ti content) or (Bi content-Nb content) is equal to or greater than 1 molar part and less than 7.5 molar parts and the total content of Cu, Ba, Zn and Li is equal to or greater than 1 molar part and less than 10 molar parts.

"It is preferable that in the multilayer ceramic capacitor of the present invention, the primary ingredient of the internal electrode is Al.

"A dielectric ceramic of the present invention includes any bismuth layered compound containing Sr, Bi and Ti, a bismuth layered compound containing Sr, Bi and Nb, and a bismuth layered compound containing Ca, Bi and Ti as a primary ingredient, Bi and at least one of Cu, Ba, Zn and Li; and satisfies such a condition that if the Ti content is 400 molar parts or the Nb content is 200 molar parts, then (Bi content-Ti content) or (Bi content-Nb content) is equal to or greater than 1 molar part and less than 7.5 molar parts and the total content of Cu, Ba, Zn and Li is equal to or greater than 1 molar part and less than 10 molar parts.

"The dielectric ceramic of the present invention can be used in a multilayer ceramic electronic component.

"It is preferable that in the dielectric ceramic electronic component of the present invention, the primary ingredient of the internal electrode is Al.

"A method for manufacturing the multi layer ceramic capacitor of the present invention includes the steps of: preparing primary ingredient powder including any bismuth layered compound containing Sr, Bi and Ti, a bismuth layered compound containing Sr, Bi and Nb, and a bismuth layered compound containing Ca, Bi and Ti as a primary ingredient; preparing at least one of Cu compound, Ba compound, Zn compound and Li compound; preparing Bi compound; blending the primary ingredient power, at least one of the Cu compound, the Ba compound, the Zn compound and the Li compound, and the Bi compound to offer a ceramic slurry; obtaining a ceramic green sheet from the ceramic slurry; laminating the ceramic green sheet and an internal electrode layer to offer a non-sintered multilayer body; and sintering the non-sintered multilayer body to offer a multilayer body with an internal electrode formed between dielectric layers. The multilayer body satisfies the condition that if the Ti content is 400 molar parts or the Nb content is 200 molar parts, then (Bi content-Ti content) or (Bi content-Nb content) is equal to or greater than 1 molar part and less than 7.5 molar parts and the total content of Cu, Ba, Zn and Li is equal to or greater than 1 molar part and less than 10 molar parts.

"Advantageous Effects of Invention

"According to the present invention, it is possible to provide a dielectric ceramic having flat capacitance characteristics and a high dielectric constant, contributing greatly to making a multilayer ceramic electronic component smaller in size and higher in performance.

BRIEF DESCRIPTION OF DRAWINGS

"FIG. 1 is a schematic view illustrating an example of a multilayer ceramic capacitor representing a multilayer ceramic electronic component of the present invention."

URL and more information on this patent application, see: Suzuki, Shoichiro; Banno, Koichi; Kanzaki, Taisuke; Shiota, Akihiro. Multilayer Ceramic Capacitor, Dielectric Ceramic, Multilayer Ceramic Electronic Component, and Method for Manufacturing Multilayer Ceramic Capacitor. Filed September 19, 2013 and posted January 23, 2014. Patent URL: http://appft.uspto.gov/netacgi/nph-Parser?Sect1=PTO2&Sect2=HITOFF&u=%2Fnetahtml%2FPTO%2Fsearch-adv.html&r=3904&p=79&f=G&l=50&d=PG01&S1=20140116.PD.&OS=PD/20140116&RS=PD/20140116

Keywords for this news article include: Murata Manufacturing Co. Ltd.

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Source: Politics & Government Week


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