Murata Manufacturing Co., Ltd.

Atsushi Kishimoto

Hideaki Niimi

Akinori Nakayama

Hayato Katsu

Takuo Wakaoka

Kenjirou Mihara

Masato Goto

Naoaki Abe

Osamu Chikagawa

Tatsuhiro Numoto

Akira Ando

Hiroshi Nishikawa

Haruhiko Ikeda

Kenjiro Mihara

Norikazu Kume

Masahiro Kodama

Mitsutoshi Kawamoto

Tadamasa Miura

Takahiro Takada

Shuichi Kawata

Hideaki Nimi

Masato Inaoka

Wataru Aoto

Takashi Shimizu

Masatoshi Kakue

Takumi Masaki

A multilayer circuit board includes a board body including insulator layers stacked upon each other, a first land pattern at the board body to mount a passive component, a second land pattern at the board body to mount an active component, and a heat-dissipation layer between the insulator layers and extending along main surfaces of the insulator layers. The heat-dissipation layer includes a hole extending therethrough in a stacking direction of the insulator layers. In a plan view from the stacking direction, an outer edge of the hole of the heat-dissipation layer is on an outer side of the first land pattern, or overlaps the first land pattern.

Multilayer circuit board and electronic-component mount multilayer board

A multilayer wiring substrate according to the present invention includes a dielectric base body, a signal line in or on the dielectric base body, a ground conductor in the dielectric base body, and a graphite sheet in the dielectric base body. The dielectric base body is a laminate including dielectric sheets stacked on top of each other. The ground conductor and the signal line face each other in a stacking direction of the dielectric sheets. The ground conductor overlaps the signal line when viewed in plan in the stacking direction. The graphite sheet and the signal line face each other in the stacking direction without the signal line being located between the graphite sheet and the ground conductor. An upper surface of the graphite sheet is coplanar with an upper surface of the ground conductor or is located below the upper surface of the ground conductor.

Multilayer wiring substrate

A vapor chamber that includes a housing having a first sheet and a second sheet facing each other, wherein at least a part of an outer edge of the housing has a step shape in which an end portion of the second sheet is positioned inside an end portion of the first sheet, and the housing has a bonded portion inside the end portion of the second sheet where the first sheet and the second sheet are bonded to each other; a protective film covering a boundary between the end portion of the second sheet and the first sheet at the step shape; a working fluid enclosed in the housing, and a wick on an inner wall surface of the first sheet or the second sheet.

Vapor chamber

A vapor chamber that includes a housing, a wick structure joined to a major inside surface of the housing, and a working liquid enclosed inside the housing. The wick structure is joined to the housing at a joint portion within a joint region, and a proportion of a total area of the joint portion within the joint region to an area of the joint region is 50% or less.

A vapor chamber includes a housing including first and second sheets that face each other and that include respective outer edge portions joined to each other, supports that support the first and second sheets from inside and that are disposed therebetween, and a hydraulic fluid enclosed in the housing. The first and second sheets do not include an angled portion having an angle of about 90&#xb0; or less between a joint and a support nearest to the joint. The expression 0.02&#x2264;b/a&#x2264;0.3 is satisfied, where a is a distance from an outer edge of the outermost support to an inner edge of the joint between the first and second sheets, and b is a distance between the first and second sheets at the outer edge of the outermost support.

A vapor chamber that includes a housing composed of a first sheet and a second sheet facing each other and having outer edge portions thereof joined to each other to define an internal space, the second sheet having a plurality of projecting portions on an inner surface thereof that faces the internal space; a pillar between the first sheet and the second sheet and supporting them from the internal space; a wick arranged in the housing, and a working fluid enclosed in the housing. A first flow path and a second flow path are formed in the internal space, and a cross-sectional area of the second flow path is larger than a cross-sectional area of the first flow path.

A sheet-shaped heat pipe includes a sheet-shaped container, a wick sealed in the container, and a working fluid sealed in the container, the sheet-shaped container including a first metal sheet and a second metal sheet, the first metal sheet and the second metal sheet being superposed in direct contact with each other at a peripheral edge portion, and the sheet-shaped container having a thickness of about 0.5 mm or less, and a thin heat dissipating plate that includes the sheet-shaped heat pipe.

Sheet-shaped heat pipe

A semiconductor ceramic and a positive-coefficient characteristic thermistor are provided which have a stable PTC characteristic, a high double point, and a wide operating temperature range. The semiconductor ceramic contains, as a main component, a barium titanate-based composition having a perovskite structure expressed by a general formula ABO. Out of 100 mol % of the Ti, an amount in a range of 0.05 mol % or more to 0.3 mol % or less of Ti is replaced with W as a semiconductor forming agent, the ratio m of A sites mainly to B sites is 0.99&#x2266;m&#x2266;1.002, and an actually-measured sintered density is 70% or more and 90% or less of the theoretical sintered density. In the positive-coefficient characteristic thermistor, a component body is formed of the semiconductor ceramic.

Semiconductor ceramic and positive-coefficient characteristic thermistor

A semiconductor ceramic includes a BaTiO-based composition, as a main component, having a perovskite structure represented by general formula ABO, wherein part of Ba constituting the A site is replaced with Na, Bi, Ca, and a rare-earth element having an ionic radius smaller than that of the Na; the content of the rare-earth element when the total number of moles of the elements constituting the A site is 1 mole is 0.0005 to 0.015 on a molar basis; and the content of the Ca when the total number of moles of the elements constituting the A site is 1 mole is 0.05 to 0.20 (preferably 0.125 or more and 0.175 or less) on a molar basis. A PTC thermistor includes a component bodyformed of the semiconductor ceramic. Accordingly, high reliability is achieved even if an alkali metal element is present.

Semiconductor ceramic and positive temperature coefficient thermistor

A semiconductor ceramic includes a BaTiO-based composition, as a main component, having a perovskite structure represented by general formula ABO. The molar ratio m between the A site and the B site satisfies 1.001&#x2266;m&#x2266;1.01. Part of Ba constituting the A site is replaced with Bi, Ca, a rare-earth element, and Na. The molar content of the Ca when the total number of moles of the elements constituting the A site is 1 mole is 0.05 to 0.20 (preferably 0.125 to 0.175). A PTC thermistor includes a component body formed of the semiconductor ceramic. Accordingly, there is provided a lead-free semiconductor ceramic that substantially does not contain lead and that has desired PTC characteristics and high reliability.

A semiconductor ceramic includes a BaTiO-based composition, as a main component, having a perovskite structure represented by general formula ABO. Part of Ba constituting an A site is replaced with at least an alkali metal element, Bi, and a rare-earth element, and the molar ratio m between the A site and a B site is 0.990&#x2266;m&#x2266;0.999 (preferably 0.990&#x2266;m&#x2266;0.995). Preferably, part of the Ba is replaced with Ca, and the content of the Ca when the total number of moles of the elements constituting the A site is 1 mole is 0.042 to 0.20 (preferably 0.125 to 0.175) on a molar basis. A PTC thermistor includes a component body formed of the semiconductor ceramic. Accordingly, there are provided satisfactory rise characteristics even if an alkali metal element is present.

A semiconductor ceramic includes a BaTiO-based composition, as a main component, having a perovskite structure represented by general formula ABO. Part of the A site Ba is replaced with an alkali metal element, Bi, Ca, Sr, and a rare-earth element. When the molar amounts of Ca and Sr are x and y, respectively, and the total number of moles of the elements constituting the A site is 1 mole, 0.05&#x2266;x&#x2266;0.20, 0.02&#x2266;y&#x2266;0.12, and 2x+5y&#x2266;0.7. A PTC thermistor includes a component body formed of the semiconductor ceramic. Even when an alkali metal element and Bi are present, there is provided a lead-free semiconductor ceramic with high reliability in which the surface discoloration is not caused and the degradation of resistance over time can be suppressed even after the application of an electric current for a long time.

A multilayer positive temperature coefficient thermistor includes a ceramic body having semiconductor ceramic layers and internal electrodes, the semiconductor ceramic layers being mainly composed of BaTiOand containing semiconductor-forming agents, the semiconductor ceramic layers and the internal electrodes being alternately stacked, and the outermost layers of the ceramic body being formed of the semiconductor ceramic layers. The outermost layers serve as protective layers. The semiconductor ceramic layers arranged between the internal electrodesandserve as effective layers. The protective layers contain a semiconductor-forming agent having a larger ionic radius than that of a semiconductor-forming agent contained in the effective layers. The protective layers have a lower porosity than that of the effective layers.

Multilayer positive temperature coefficient thermistor

A multilayer thermistor with a positive temperature coefficient is manufactured by stepof forming a green laminate having thermistor green layers and internal electrode layers, stepof heat-treating this laminate at a temperature in the range of from 80 to less than 300&#xb0; C., stepof performing dry-barrel polishing for the heat-treated green laminate, stepof forming external electrode films on respective end surfaces of this laminate, and stepof 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.

Method for manufacturing multilayer ceramic electronic component

A multilayer positive temperature coefficient thermistor that has semiconductor ceramic layers containing a BaTiO-based ceramic material as a primary component, and at least one element selected from the group consisting of Eu, Gd, Tb, Dy, Y, Ho, Er, and Tm as a semiconductor dopant in the range of 0.1 to 0.5 molar parts with respect to 100 molar parts of Ti. The ratio of the Ba site to the Ti site is in the range of 0.998 to 1.006. Accordingly, even when the semiconductor ceramic layers have a low actual-measured sintered density in the range of 65% to 90% of a theoretical sintered density, a multilayer positive temperature coefficient thermistor having a sufficiently high rate of resistance change and a high rising coefficient of resistance at the Curie temperature or more can be realized.

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Nagaokakyo, Japan

Atsushi Kishimoto