A spark plug is provided which includes a hollow cylindrical center electrode disposed inside a metal shell and a ground electrode joined to the metal shell. The ground electrode has an inner peripheral surface facing an outer peripheral surface of the center electrode. At least one of the outer periphery of the center electrode and the inner periphery of the ground electrode has formed therein at least one recess whose ends lies in a center-to-ground electrode facing region where the outer peripheral surface of the center electrode faces the inner peripheral surface of the ground electrode in a radial direction of the center electrode. This decreases voltage required by the spark plug to achieve discharge.

An ignition plug for an internal combustion engine includes an electrode protrusion that protrudes from an electrode base material of a ground electrode toward a discharge gap. The electrode protrusion has a base part that is integrated with the electrode base material and a cover part that is joined to the base part and faces the discharge gap. The base part has an end surface facing a protrusion direction of the base part and a side peripheral surface. An outer edge of the end surface has a curved surface. The cover part is formed from a precious metal or a precious metal alloy having a lower linear expansion coefficient than that of a material for forming the base part and covers at least a part of the side peripheral surface and the end surface of the base part. While the ignition plug is attached to an internal combustion engine and the electrode protrusion is heated and then cooled, a projection is formed on an outer surface of a portion covering the side peripheral surface of the base part.

The present invention is a spark gap capable of integrating into multiple layer semiconductor substrate packaging. The initial gap in the spark gap is solid and it can be converted into air, meaning gaseous, and the air gap is achieved by having the gap initially be filled with a solid and then running a voltage through the spark gap so that the gap explodes and the solid is replaced by an air cavity. The spark gap may be formed by initially electroplating electrodes through a dry film-based process, and then, to further close the gap between electrodes, beyond the practical limits of dry film, pigtail plating may be used. This pigtail plating may expand the electrodes and thus reduce the gap distance.

The present invention is a spark gap capable of integrating into multiple layer semiconductor substrate packaging. The initial gap in the spark gap is solid and it can be converted into air, meaning gaseous, and the air gap is achieved by having the gap initially be filled with a solid and then running a voltage through the spark gap so that the gap explodes and the solid is replaced by an air cavity. The spark gap may be formed by initially electroplating electrodes through a dry film-based process, and then, to further close the gap between electrodes, beyond the practical limits of dry film, pigtail plating may be used. This pigtail plating may expand the electrodes and thus reduce the gap distance.

An ESD protective device includes an element assembly with a hollow portion that includes inner surfaces including a first inner surface, a second inner surface, and a third inner surface inclined to a Z direction in a cross section including the Z direction. Accordingly, a surface area of the inner surfaces of the hollow portion is increased, the heat load on an auxiliary discharge electrode is reduced, and the deterioration of the auxiliary discharge electrode is significantly reduced or prevented.

An ESD protective device includes an element assembly with a hollow portion that includes inner surfaces including a first inner surface, a second inner surface, and a third inner surface inclined to a Z direction in a cross section including the Z direction. Accordingly, a surface area of the inner surfaces of the hollow portion is increased, the heat load on an auxiliary discharge electrode is reduced, and the deterioration of the auxiliary discharge electrode is significantly reduced or prevented.

An arrester and a method for producing an arrester are disclosed. In an embodiment the method includes providing at least three green layers, wherein each layer includes at least one green sheet, introducing at least one hole into a first layer and applying an electrically conductive material for forming inner electrodes to a second layer and a third layer. The method further includes laminating the layers to form a green stack, wherein the first layer is arranged between the second layer and the third layer, separating the green stack into individual components and compacting the individual components, wherein laminating the layers and compacting the individual components are effected in a single temperature process by co-firing.

An arrester and a method for producing an arrester are disclosed. In an embodiment the method includes providing at least three green layers, wherein each layer includes at least one green sheet, introducing at least one hole into a first layer and applying an electrically conductive material for forming inner electrodes to a second layer and a third layer. The method further includes laminating the layers to form a green stack, wherein the first layer is arranged between the second layer and the third layer, separating the green stack into individual components and compacting the individual components, wherein laminating the layers and compacting the individual components are effected in a single temperature process by co-firing.

An arrester comprising a plurality of layers arranged one above another and comprising a cavity is specified, wherein the cavity extends through at least two of the layers and wherein electrodes adjoining the cavity are arranged between said two layers. Furthermore, a method for manufacturing an arrester is specified.

An arrester comprising a plurality of layers arranged one above another and comprising a cavity is specified, wherein the cavity extends through at least two of the layers and wherein electrodes adjoining the cavity are arranged between said two layers. Furthermore, a method for manufacturing an arrester is specified.