Tdk Corporation

Ryuichi Tanaka

Hiroyuki Sato

Goro Takeuchi

Yo Saito

Makoto Numata

Osamu Taguchi

Hitoshi Tanaka

Tadashi Ogasawara

Mikikazu Takehana

A multilayer chip varistor is provided as one capable of suppressing production of cracks and thereby preventing a connection failure between an internal electrode and a through-hole conductor. An internal electrodeis so configured as to be curved toward a direction of penetration of a through holein a connection portionthereof to a through-hole conductor. By this configuration, a region T sandwiched between a curved surfaceof the connection portionand the through-hole conductoris formed in a varistor layernear the connection portion. In this region T, a metal concentration thereof becomes higher because of diffusion of metal of the internal electrodeand the through-hole conductorinto the varistor layer, and therefore, after completion of firing, the region T has an intermediate contraction percentage between that of the internal electrodeand through-hole conductorand that of the other region of the varistor layer. This permits the region T to relax stress near the connection portionwhere the internal electrode, through-hole conductor, and varistor layerare congested so as to readily produce cracks.

Multilayer chip varistor

An aggregate substrate has a first varistor part, a second varistor part, and a heat dissipation layer. The first varistor part includes a first varistor element layer to exhibit nonlinear voltage-current characteristics, and a plurality of first internal electrodes juxtaposed in the first varistor element layer. The second varistor part includes a second varistor element layer to exhibit nonlinear voltage-current characteristics, and a plurality of second internal electrodes juxtaposed in the second varistor element layer. The heat dissipation layer is located between the first and second varistor parts and is in contact with the first and second varistor parts.

Aggregate substrate, production method of aggregate substrate, and varistor

A varistor having a favorable heat-dissipating property is provided. In the varistor, a composite part having a favorable heat-dissipating property formed by a composite material composed of ZnO and Ag is arranged between main faces of a varistor matrix. Therefore, the heat transmitted from a semiconductor light-emitting device to a varistor part through an outer electrode can rapidly be transferred toward a main face on the opposite side through the composite part. In this varistor, side faces excluding inner side faces are exposed at side faces of the varistor matrix. Such a structure yields a favorable heat-dissipating property.

Varistor

A first varistor section includes a first face of an element body, and a third face facing the first face. The first varistor section has a first varistor element body, a first varistor electrode electrically connected to a first external electrode, and a second varistor electrode electrically connected to a second external electrode. A heat radiation section has a first heat radiation portion kept in contact with the third face of the first varistor section and electrically connected to the first and third external electrodes, a second heat radiation portion kept in contact with the third face of the first varistor section and electrically connected to the second and fourth external electrodes, and an insulating layer located between the first heat radiation portion and the second heat radiation portion and electrically insulating the first heat radiation portion and the second heat radiation portion from each other. The first heat radiation portion and the second heat radiation portion contain a metal.

In a varistor, a heat radiating portion contains the same components as ZnO that is the main component of a varistor element body, as metal oxides, thereby, the structural components of the varistor element body and the heat radiating portion are caused to be common. During firing, Ag contained in the heat radiating portion diffuses into the grain boundaries of ZnO, near the interface between surfaces of the heat radiating portion and the varistor element body. Consequently, in the varistor, cracks hardly occur between the varistor portion and the heat radiating portion during firing (or during binder removal), thereby, ensuring sufficient bonding strength between the varistor portion and the heat radiating portion. Therefore, heat conducted to the varistor portion is radiated efficiently conducting through electrically conducted paths formed in the heat radiating portion from the surface facing the varistor element body to other three surfaces of the heat radiating portion.

Varistor and light emitting device

A multilayer chip varistor is provided as one having excellent heat radiation performance. A thickness between a first principal faceand an outermost internal electrode layerA is smaller than a thickness between an internal electrode layerand the outermost internal electrode layerA, and because of this configuration, heat generated from a bottom face of a semiconductor light emitting device LEis efficiently transferred to the outermost internal electrode layerA having a high thermal conductivity. Furthermore, in the multilayer chip varistor Vof an electronic component EC, the outermost internal electrode layerA has a first internal electrodeelectrically connected to a first connection electrodeand a first terminal electrodethrough first through-hole conductors, and a second internal electrodeelectrically connected to a second connection electrodeand a second terminal electrodethrough second through-hole conductors. Because of this configuration, heat H generated from the semiconductor light emitting device LEis transferred to both the first internal electrodeand the second internal electrode, so as to be transferred to the first through-hole conductorsand the second through-hole conductors. This leads to well-balanced transfer of heat to the first through-hole conductorsand the second through-hole conductors

Multilayer chip varistor and electronic component

A semiconductor electronic part includes a semiconductor ceramic substrate and at least one internal electrode. The internal electrode is disposed inside the semiconductor ceramic substrate and includes an end led out to an end edge of the semiconductor ceramic substrate and at least one cutout region. It is preferable that the internal electrode has a plurality of the cutout regions. Further preferably, the plurality of the cutout regions are arranged to be distanced from one another in a direction of width of the semiconductor ceramic substrate.

Semiconductor electronic part

A laminate type varistor has at least one pair of first and second inner electrodes and a varistor layer. The at least one pair of first and second electrodes and the varistor layer are laminated. A first outer electrode and a second outer electrode electrically are connected to the first inner electrode and the second inner electrode, respectively. In the laminate type varistor, the first inner electrode and the first inner electrode are separated by a predetermined distance from the outer electrode so that the first inner electrode has no electrode surface facing to an electrode surface of the second inner electrode.

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Tokyo, Japan

Ryuichi Tanaka