JPH0566951U - Monolithic ceramic capacitors - Google Patents

Abstract

(57) [Summary] [Purpose] Moisture resistance is greatly improved, which in turn improves long-term reliability. A structure in which an electrode layer 1 made of a conductor and a dielectric layer 2 made of a ceramic are alternately laminated, and each electrode layer is alternately connected to the external electrodes 3 on both end surfaces, wherein the surface layer of the electrode layer Since it has the protective electrode layer 4 which is located on the same outer surface of the outside, is connected to both external electrodes, and is separated in the middle part, most of the moisture invading from the outside is blocked by the protective electrode layer. To do.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a laminated ceramic capacitor.

[0002]

[Prior Art]

 As shown in FIG. 2, a monolithic ceramic capacitor mass-produced as one of the typical passive components used in electronic equipment has an electrode layer 21 made of a conductor such as silver and palladium and a barium titanate-titanium oxide-based one. And the dielectric layers 22 made of ceramic are alternately laminated, and the electrode layers 21 are alternately connected to the external electrodes 23 made of a conductor such as silver on both end surfaces.

In this multilayer ceramic capacitor, after a paste-like electrode material made of platinum, palladium, silver, or the like is printed on the surface of a dielectric sheet made of ceramic, the dielectric sheets are stacked in multiple layers, pressed and fired, In addition, it is manufactured by forming external electrodes whose main component is silver palladium, etc. on both end faces, and in terms of an equivalent circuit, multiple capacitors are connected in parallel.

[0004]

[Problems to be solved by the device]

 In this conventional monolithic ceramic capacitor, the thickness of the dielectric layer is made as thin as possible in order to obtain the smallest possible size and large capacity. Currently mass-produced products are of the level of 15 to 30 μm, and those of the 10 μm level have already been put into practical use. The chip type monolithic ceramic capacitors, which are used in the largest amount, have a bare structure with no exterior resin.

[0007] Thus, the multilayer ceramic capacitor has been able to obtain considerable quality and reliability by performing sufficient quality control in manufacturing, but it has not yet been obtained with complete reliability. . The biggest problems are insulation deterioration and short circuits that occur over time during use.

The decrease in insulation resistance and the short circuit are caused by defects in the ceramic sheet that is the dielectric layer.

That is, the defects penetrating the dielectric layer interposed between the opposing electrode layers are generated by the action of the moisture invading from the surface layer and the movement of the electrode material by the DC voltage between the electrode layers. is there. The most typical phenomenon is migration of silver or palladium.

The above-mentioned decrease in insulation resistance and the like often occurs between the outermost electrode layers because all the moisture penetrates from the surface layer.

Therefore, an object of the present invention is to provide a monolithic ceramic capacitor having a significantly improved moisture resistance and a high long-term reliability.

[0010]

[Means for Solving the Problems]

 The monolithic ceramic capacitor of the present invention is a monolithic ceramic capacitor in which electrode layers made of a conductor and dielectric layers made of ceramic are alternately laminated, and each electrode layer is alternately connected to external electrodes on both end faces. The protective electrode layer is provided outside the surface layer of the electrode layer in the same plane, is connected to both external electrodes, and is separated at an intermediate portion.

[0011]

[Action]

 In the above means, most of the moisture that has entered from the outside is blocked by the protective electrode layer.

[0012]

【Example】

 Next, the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a monolithic ceramic capacitor according to an embodiment of the present invention.

In this monolithic ceramic capacitor, an electrode layer 1 made of a conductor such as silver or palladium and a dielectric layer 2 made of barium titanate or titanium oxide based ceramic are alternately laminated, and each electrode layer 1 is It has a structure in which the protective electrode layers 4 are alternately connected to the outer electrodes 3 on both end surfaces made of a conductor such as silver, and the protective electrode layers 4 are provided in the same plane outside the upper and lower surface layers of the electrode layer 1. The protective electrode layer 4 is connected to both external electrodes 3 and is separated at an intermediate portion.

The protective electrode layer 4 is formed by shifting the stacking position from the inner electrode layer 1 by 1/2. Therefore, it can be manufactured extremely easily.

[0016]

[Effect of the device]

 As described above, according to the monolithic ceramic capacitor of the present invention, most of the moisture invading from the outside is blocked by the protective electrode layer, so that the electrode tip of the surface layer, which has conventionally been the cause of the deterioration of insulation resistance. It is possible to significantly reduce the formation of conductive paths in the portion, significantly improve the moisture resistance, and, in turn, the long-term reliability can be extremely enhanced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a monolithic ceramic capacitor according to an embodiment of the present invention.

FIG. 2 is a sectional view of a conventional monolithic ceramic capacitor.

[Explanation of symbols]

 1 Electrode Layer 2 Dielectric Layer 3 External Electrode 4 Protective Electrode Layer

Claims (1)

[Scope of utility model registration request] 1. A multilayer ceramic capacitor in which electrode layers made of conductors and dielectric layers made of ceramics are alternately laminated, and each electrode layer is alternately connected to external electrodes on both end surfaces of the electrode layer. A monolithic ceramic capacitor, characterized in that it comprises a protective electrode layer located outside the layer in the same plane, connected to both external electrodes and separated at an intermediate part.