JP2000133545A - Laminated ceramic chip capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrain discharging from front surfaces as well as side surfaces and provide a small-sized laminated ceramic chip capacitor of high capacity and high breakdown voltage. SOLUTION: To the basic structure, where a plurality of internal electrodes 1a to 1e and a plurality of dielectrics layers 2a to 2h are laminated alternately, a pair of supplementary electrodes 6a, 6b are additionally provided in parallel, having predetermined gaps G1, G2 on the side of internal terminals positioned as the outermost layer of internal electrodes 1a to 1e for controlling the surface discharge and supplementary electrodes 7a, 7b, 8a, 8b positioned in a pair on both ends which are closer to the outside than the internal electrodes 1a to 1e. These supplementary electrodes for controlling discharges are electrically connected with other external electrodes by pairs.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer ceramic capacitor having a small size, a high capacity, and a high withstand voltage for a microcomputer and other various electronic devices.

[0002]

2. Description of the Related Art Generally, a multilayer ceramic capacitor is shown in FIG.
As shown by a plurality of opposed internal electrodes 10a to 10f
And with a dielectric layer 11a~11f by stacked multiple alternately to form the capacitor element _{C 1,} the internal electrodes 10
a~10f sequentially staggered by another external electrodes 12 and 13 electrically connected to it is formed by providing the external electrodes 12 and 13 on both ends of the ceramic element _{C 1.}

In the multilayer ceramic capacitor, the area of the internal electrodes 10a to 10f is large and the dielectric layers 11a to 10f are large.
The smaller the thickness of a to 11f, the larger the capacity. However, when a thin dielectric layer 11a to 11f is used for high voltage, dielectric breakdown may occur due to concentration of an electric field at an electrode end.

[0004] may be increased the distance d ₁ of the voltage mutual opposed to achieve the high voltage, but the capacitor element C
_If the polarities of the internal electrodes 10a and 10e closest to the surface of the _first pattern are opposite to the polarities of the land patterns, surface discharge is likely to occur. This is avoided by displaying polarity capacitor element C _1, handling of time of component mounting is cumbersome.

[0005] Alternatively, the closest internal electrode 10a on the surface of the capacitor element _{C 1,} 10f and the capacitor element C
May increase the distance d ₂ between the _first surface, it can not be correspond to the size reduction in this.

[0006] Therefore the problem to solve, by a pair of electrodes parallel spaced phase inner end a predetermined gap G ₃ as shown in Figure 9, a plurality of connecting external electrodes 20 and 21 electrically separate The internal electrodes 22a, 22b to 25a, 25b and the internal electrodes 22 without being electrically connected to the external electrodes 20, 21.
a, 22b~25a, the internal electrode 26a~26c which faces the inner end of 25b, and a dielectric layer 27a~27h by stacked multiple alternately is proposed laminated ceramic capacitors to form a capacitor element _{C 2} (Shinkai Kaisho 5
No. 4-5755).

The multilayer ceramic capacitor can withstand a high voltage because the voltage is shared by the capacitors connected in series. However, in order to obtain a capacitance equivalent to that of the configuration shown in FIG. Must be formed more than twice.

[0008] In addition, an internal electrode 30a~30e and, pairs of parallel spaced phase inner end a predetermined gap _{G 4} electrode a plurality of opposed, as shown in Figure 10, the internal electrodes 30a~3
Auxiliary electrode 31 for controlling surface discharge located at the outermost layer
a, 31b, 32a, 32b and dielectric layers 33a-33
and h into a plurality alternately stacking a plurality to form a capacitor element C _3, each electrode is different multilayer ceramic capacitor to external electrodes 34 and 35 electrically connected is known (Journal of Technical Disclosure: Branch number 90-18959).

In the multilayer ceramic capacitor, auxiliary electrodes 31a, 31b, 32a, 32b for controlling surface discharge are provided.
However, even if the surface discharge can be suppressed, the side discharge cannot be suppressed.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to provide a multilayer ceramic capacitor which can suppress a discharge on a side surface as well as a discharge on a surface, and can be formed into a small, high-capacity, high-withstand voltage capacitor.

[0011]

In a multilayer ceramic capacitor according to a first aspect of the present invention, a plurality of internal electrodes and a plurality of dielectric layers facing each other are alternately laminated to form a capacitor element. It has a basic structure in which the internal electrodes are sequentially and alternately electrically connected to another external electrode and the external electrodes are provided at both ends of the ceramic element, and a pair of electrodes that are parallel to each other with a predetermined gap on the inner end side, An auxiliary electrode for surface discharge control located on the outermost layer of the internal electrode, and auxiliary electrodes for side discharge control located on both sides in pairs outside of the internal electrode and the auxiliary electrode for surface discharge control are added. Each of the auxiliary electrodes for controlling discharge is electrically connected to another external electrode for each pair.

In the multilayer ceramic capacitor according to a second aspect of the present invention, the auxiliary electrode for controlling side discharge is provided at least in correspondence with the internal electrode.

In the multilayer ceramic capacitor according to a third aspect of the present invention, the auxiliary electrode for controlling side discharge is provided in correspondence with the internal electrode and the auxiliary electrode for controlling the surface.

In the multilayer ceramic capacitor according to a fourth aspect of the present invention, an auxiliary electrode for controlling side discharge is provided for each electrode in at least two layers.

The multilayer ceramic capacitor according to claim 5 of the present invention is constituted by adding a dielectric layer laminated only with an auxiliary electrode for controlling side discharge.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the accompanying drawings, FIGS. 1A and 1B show a basic embodiment of a multilayer ceramic capacitor according to the present invention. Internal electrodes 1a-1e and dielectric layer 2a
To 2e are alternately laminated in plural to form a capacitor element C
Is formed, and the internal electrodes 1a to 1e are sequentially and alternately electrically connected to other external electrodes 3 and 4, so that the external electrodes 3 and 4 are provided at both ends of the ceramic element C.

The dielectric layers 2a to 2e are dielectric sheets. The internal electrodes 1a to 1e are formed by printing a conductive paste such as nickel on the surface of the dielectric sheet. Are laminated and fired, whereby the internal electrodes 1a to 1e and the dielectric layers 2a to 2e are formed.
Are alternately arranged as capacitor elements C.

The external electrodes 3 and 4 are formed by applying and baking a conductive paste such as copper as a base electrode, and depositing a nickel electrolytic plating film and an electrolytic plating film of nickel, tin or an alloy thereof. .

[0019] In addition to its basic structure, the electrode pairs of parallel inner end in spaced phase a predetermined gap G ₁ as shown in FIG. 1a, a surface discharge control located on the outermost layer of the internal electrode 1a~1e Auxiliary electrodes 5a, 5b, 6a, 6b are
To 2h.

Auxiliary electrodes 5a, 5 for controlling the surface discharge
b, 6a, along with 6b, the electrode pairs of parallel inner end in spaced phase a predetermined gap G ₂ as shown in 1b, the internal electrodes 1
a, 1b and side discharge control auxiliary electrodes 7a, 7b, 8a, 8b located on both sides in pairs outside of the surface discharge control auxiliary electrodes (not shown) are laminated on the dielectric layer 2a. It is provided.

Auxiliary electrodes 7a, 7 for controlling side discharge
b, 8a and 8b are the same dielectric layers 2 as the internal electrodes 1a to 1e.
a, and a conductive paste such as nickel or the like, including the auxiliary electrodes 5a, 5b, 6a, and 6b for controlling surface discharge, is formed on the dielectric sheet in the same manner as the internal electrodes 1a to 1e described above. It is formed by printing. Also,
A capacitor element C is formed by laminating a dielectric sheet on which these electrodes are formed in a predetermined layer.

In the capacitor element C, as shown in FIG. 2, auxiliary electrodes 7a, 7c to 7f, 8f for controlling side discharge.
a, 8c to 8f (only one side of each pair is shown) are provided corresponding to at least the internal electrodes 1a to 1e. Further, as shown in FIGS. 1A and 1B, an auxiliary electrode 5 for controlling surface discharge is provided.
a, 5b, 6a, 6b and auxiliary electrodes 7 for controlling side discharge
Each of the pairs a to 7f and 8a to 8f is electrically connected to the external electrodes 3 and 4 individually.

In the multilayer ceramic capacitor configured as described above, the distributed capacitance is controlled by the auxiliary electrode 5 for controlling surface discharge.
It can be reduced not only by a, 5b, 6a and 6b, but also by auxiliary electrodes 7a to 7f and 8a to 8f for side discharge control. Therefore, the internal electrodes 1a to 1e and the dielectric layers 2a to 2e
2e and a basic structure in which a plurality of 2e are alternately stacked, a small-sized and high-capacity one can be configured, and a discharge generated from the internal electrodes 1a to 1e can be suppressed, so that a high-voltage one can be configured.

When the discharge withstand voltage of the multilayer ceramic capacitor was measured, as shown in the graph of FIG. 3, it was 1500 to 2000 V for the conventional product A of FIG. 9 and 2500 to 3000 V for the conventional product B of FIG. In contrast, the product of the present invention exhibited an extremely high withstand voltage of 3500 to 4000 V.

The auxiliary electrode for controlling side discharge is the internal electrode 1a.
In addition to those corresponding to .about.1e, those corresponding to auxiliary electrodes 5a and 5b for surface discharge control as shown in FIG.
7i, 8h, 8i, auxiliary electrodes 5 for controlling surface discharge
a and 5b can be provided on the same surface of the dielectric layer 2i.

Auxiliary electrodes 7h, 7 for controlling side discharge
i, 8h and 8i are auxiliary electrodes 5a and 5b for controlling surface discharge.
Therefore, the side discharge can be more effectively suppressed.

As shown in FIG. 5, only the auxiliary electrodes 7j, 7k, 8j, 8k for controlling the side discharge can be provided on the surface of the dielectric layer 2j.

The auxiliary electrode for controlling the lateral discharge is provided on the surface of the dielectric layer different from the internal electrode and the auxiliary electrode for controlling the surface discharge, and as shown in FIG.
1e, the auxiliary electrodes 5a and 6a for controlling surface discharge can be laminated between different layers.

Auxiliary electrodes 7h, 7 for controlling side discharge
j, 8h and 8j are auxiliary electrodes 5a and 6 for controlling surface discharge.
The capacitor element C can be stacked outside the surface of the capacitor element C near the surface side. This can further effectively prevent dielectric breakdown due to concentration of an electric field at the electrode end.

As shown in FIG. 7, the auxiliary electrode for controlling the side discharge corresponds to the internal electrodes 1a to 1e, and the dielectric layer 2j provided with only the auxiliary electrodes 7j and 8j for controlling the side discharge shown in FIG. Can be laminated between predetermined layers in at least two layers.

When the side discharge control auxiliary electrode is provided, the side discharge is controlled by a plurality of side discharge control auxiliary electrodes 7.
Since j and 8j can be shared, the side discharge can be more effectively suppressed together with the surface discharge.

[0032]

As described above, according to the multilayer ceramic capacitor of the present invention, the basic structure of alternately laminating a plurality of internal electrodes and dielectric layers can be reduced to a small size and high capacity. A pair of electrodes that are parallel to each other with the gap between them on the inner end side, and a pair of electrodes that are located on the outermost layer of the internal electrodes and that are more outward than the internal electrodes and the auxiliary electrodes for surface discharge control. By adding auxiliary electrodes for side discharge control located on both sides, the distributed capacitance can be reduced not only by the auxiliary electrodes for surface discharge control but also by the auxiliary electrodes for side discharge control. Can be effectively suppressed and a high breakdown voltage device can be configured.

[Brief description of the drawings]

FIG. 1a is an explanatory view showing a multilayer ceramic capacitor according to the present invention in a side sectional view.

FIG. 1B is an explanatory view showing an example of a dielectric layer constituting the multilayer ceramic capacitor of FIG. 1A in a plane.

FIG. 2 is an explanatory view showing a cross section of the multilayer ceramic capacitor of FIG. 1;

FIG. 3 is a graph showing discharge withstand voltages of a multilayer ceramic capacitor according to the present invention and a conventional example.

FIG. 4 is an explanatory view showing another example of a dielectric layer constituting the multilayer ceramic capacitor of FIG. 1A in a plane.

FIG. 5 is an explanatory view showing, in a plane, still another example of a dielectric layer included in the multilayer ceramic capacitor of FIG. 1A.

FIG. 6 is an explanatory view showing a cross-sectional view of a multilayer ceramic capacitor according to another example of the present invention.

FIG. 7 is an explanatory diagram showing a cross-sectional view of a multilayer ceramic capacitor according to still another example of the present invention.

FIG. 8 is an explanatory diagram showing a side view of a multilayer ceramic capacitor according to a conventional example.

FIG. 9 is an explanatory view showing a side view of a multilayer ceramic capacitor according to another example of the related art.

FIG. 10 is an explanatory view showing a side cross section of a multilayer ceramic capacitor according to still another conventional example.

[Explanation of symbols]

C Capacitor element 1a-1e Internal electrode 2a-2h Dielectric layer 3,4 External electrode 5a, 5b External electrode 6a, 6b for surface discharge control External electrode 7a, 7b External electrode for side discharge control 8a , 8b Gap between the inner ends of the outer electrodes G ₁ , G ₂ for controlling the side discharge

Continued on the front page F-term (reference) 5E001 AB03 AC07 AC09 AF00 AF06 AH01 AH09 AJ01 5E082 AA01 AB03 BC35 EE04 EE23 EE35 FG06 FG26 FG54 GG10 GG11 GG26 GG28 HH43 JJ03 JJ05 JJ12 JJ21 JJ23 KK01 MM01

Claims (5)

[Claims] 1. A capacitor element is formed by alternately laminating a plurality of opposing internal electrodes and a plurality of dielectric layers to form a capacitor element, and sequentially connecting the internal electrodes to another external electrode alternately and electrically. A basic structure in which electrodes are provided at both ends of the ceramic element, a pair of electrodes parallel to each other with a predetermined gap on the inner end side, and an auxiliary electrode for surface discharge control located on the outermost layer of the internal electrode;
An internal electrode and auxiliary electrodes for side surface discharge control located on both sides in pairs outside of the auxiliary electrode for surface discharge control are added, and each auxiliary electrode for discharge control is a separate external electrode for each pair. A multilayer ceramic capacitor characterized by being electrically connected to a multilayer ceramic capacitor. 2. The multilayer ceramic capacitor according to claim 1, wherein said side discharge control auxiliary electrode is provided corresponding to at least an internal electrode. 3. The multilayer ceramic capacitor according to claim 1, wherein the auxiliary electrode for controlling the side discharge is provided in correspondence with the internal electrode and the auxiliary electrode for controlling the surface. 4. The multilayer ceramic capacitor according to claim 2, wherein the auxiliary electrodes for controlling the side discharge are provided corresponding to at least two layers for each electrode. 5. A method according to claim 2, further comprising the step of adding a dielectric layer laminated only with the auxiliary electrode for controlling the side discharge.
5. The multilayer ceramic capacitor according to any one of 4.