JPH09260205A - Laminated capacitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laminated capacitor which enables an inside electrode formation position to be readily recognized from the outside. SOLUTION: A laminated capacitor is comprised of an element assembly 33 which is formed by laminating and baking a dielectric layer and an inside electrode 32 alternately and a pair of outside electrodes 34 connecting the inside electrode 32 in parallel alternately in both end parts of the element assembly 33, and has a discolored part 34a wherein the outside electrode 34 in a part in contact with an end part of the inside electrode 32 in an edge face of the element assembly 33 is discolored corresponding to a formation position of the inside electrode 32. Since a formation position of the inside electrode 32 can be readily recognized from an outside, lamination irregularity, etc., of the inside electrode 32 can be readily detected and the inside electrode 32 out of position can be readily recognized even in a capacitor wherein the inside electrode 32 is positioned one-sidedly.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer capacitor, and more particularly to a small multilayer capacitor.

[0002]

2. Description of the Related Art FIGS. 2 to 4 show a conventional multilayer capacitor. 2 is an exploded perspective view, FIG. 3 is a plan view, and FIG.
3 is a sectional view taken along line AA of FIG.

[0003] In the drawing, reference numeral 10 denotes a multilayer capacitor in which a dielectric body 13 formed by alternately laminating dielectric layers 11 and internal electrodes 12 and internal electrodes are alternately connected in parallel at both ends of the dielectric body 13. And a pair of external electrodes 14.

Each internal electrode 12 is alternately connected to the external electrode 14 at one end or the other end thereof.

[0005] The dielectric layer 11 is formed of a ceramic sintered body on a rectangular sheet, and the ceramic sintered body is formed of a dielectric ceramic material containing, for example, barium titanate as a main component.

The internal electrode 12 is made of a metal thin film obtained by sintering a metal paste.
A material containing a precious metal material such as Ag or Pd as a main component is used. The external electrode 14 is also formed of the same material as the internal electrode 12, and the surface is plated with solder to improve solder wettability.

[0007]

However, in the above-mentioned conventional multilayer capacitor, the formation position of the internal electrode 12 cannot be discriminated from the outside, and the internal electrode 12 is misaligned as shown in FIG. Was hard to find.
In addition, as shown in FIG.
In order to suppress the generation of stray capacitance between the conductor pattern 21 on the upper surface of the internal electrode 12 and the internal electrode 12, a capacitor in which the internal electrode 12 is biased to the upper layer portion may be manufactured. In the case of such a capacitor, the internal electrode 12 It was very troublesome to identify the bias of.

In view of the above problems, it is an object of the present invention to provide a multilayer capacitor in which the internal electrode formation position can be easily recognized from the outside.

[0009]

In order to achieve the above object, the present invention provides, in claim 1, a substantially rectangular parallelepiped element body in which dielectric layers and internal electrode layers are alternately laminated, and the element body. A multilayer capacitor, which comprises a pair of external electrodes in which internal electrodes formed on the internal electrode layers are alternately connected in parallel so as to cover the end faces at both ends of a body, and which are in contact with the internal electrode ends. We propose a multilayer capacitor in which the external electrodes that are discolored change color corresponding to the positions where the internal electrodes are formed.

According to the multilayer capacitor, since the external electrode in contact with the end of the internal electrode is discolored corresponding to the formation position of the internal electrode, the formation position of the internal electrode can be easily recognized from the outside. be able to.

According to a second aspect of the present invention, a substantially rectangular parallelepiped element body is formed by alternately laminating dielectric layers and internal electrode layers, and the internal electrode layer is formed so as to cover the end faces at both ends of the element body. A multilayer capacitor comprising a pair of external electrodes in which the internal electrodes formed in the above are alternately connected in parallel, the end portions of the internal electrodes projecting outward from the end surface of the element body, and Proposed is a multilayer capacitor in which the electrode is formed by projecting a portion corresponding to the projecting portion of the internal electrode.

According to the multilayer capacitor, the end portions of the internal electrodes project outward from the end surfaces of the element body, and the external electrodes are formed so that the portions corresponding to the projecting portions of the internal electrodes project. Therefore, the formation position of the internal electrode can be easily recognized.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is an external perspective view showing a multilayer capacitor of a first embodiment of the present invention, and FIG. 7 is a side sectional view thereof. In the figure, reference numeral 30 denotes a multilayer capacitor, which is an element body 3 in which dielectric layers 31 and internal electrodes 32 are alternately laminated.
3 and a pair of external electrodes 34 in which the internal electrodes 32 are alternately connected in parallel at both ends of the element body 33.

The dielectric layer 31 is made of a rectangular sheet-shaped ceramic sintered body, and the sintered body is made of a dielectric ceramic material formed by firing a green sheet containing barium titanate as a main component, for example.

Each of the pair of internal electrodes 32 adjacent to each other through the dielectric layer 31 is rectangular, and the internal electrodes 32 are
The long side of is substantially perpendicular to the external electrode 34. In addition, the widths of the internal electrodes 32 are formed equal to each other.

Further, on the end face of the element body 33, as shown in FIG. 1, the external electrode 34 in a portion in contact with the end portion of the internal electrode 32 is discolored to a color different from the other portions.
a, the position where the internal electrode 32 is formed can be recognized from the outside.

The above-mentioned internal electrode 32 is made of a metal thin film obtained by sintering a thin film of a conductive paste, and as the conductive paste, for example, one containing palladium powder as a main component is used. The external electrode 34 is made of a material mainly containing silver (Ag). By thus selecting the metal components of the internal electrode 32 and the external electrode 34 to predetermined ones, diffusion occurs between the metal of the internal electrode 32 and the metal of the external electrode 34 when the external electrode is formed, and Metals intermingle between the end portion and the external electrode 34 in contact therewith, causing discoloration. In addition to this, as a combination of metals that cause such discoloration, nickel (Ni) is used as the internal electrode 32 and copper (C) is used as the external electrode 34.
Combinations using u) are possible.

This multilayer capacitor was manufactured as follows. First, an organic binder was added to the dielectric raw material powder.
% By weight, and further 50% by weight of water, and these were put into a ball mill and mixed well to prepare a slurry of a dielectric ceramic raw material.

Next, after putting this slurry in a vacuum defoamer to defoam it, put it in a reverse roll coater to form a thin film of this slurry on a polyester film,
This thin film is dried by heating to 100 ° C. on a polyester film, punched out, and 10 cm square, about 2 mm thick.
A green sheet of 0 μm was obtained.

On the other hand, 10 g of palladium powder having an average particle size of 1.5 μm and 0.9 g of ethyl cellulose dissolved in 9.1 g of butyl carbitol were placed in a stirrer.
By stirring for 10 hours, a conductive paste for an internal electrode was obtained.

After that, the above-mentioned internal electrode pattern
Using each of the screens having zero, a pattern of the internal electrode made of the conductive paste was printed on one surface of the green sheet, and dried.

Next, a plurality of green sheets were laminated with the printing surface facing upward, and further, unprinted green sheets were laminated on the upper and lower surfaces of this laminate. Then
This laminate was pressed at a temperature of about 50 ° C. by applying a pressure of about 40 tons in the thickness direction. Thereafter, the laminate was cut into a lattice to obtain about 50 laminated chips.

Next, this laminated chip is placed in a furnace capable of firing in an atmosphere, heated to 600 ° C. in the atmosphere to fire the organic binder, and then the atmosphere of the oven is set to the atmosphere in the atmosphere to heat the laminated chip. The temperature was maintained at 600 ° C. to 1150 ° C. (maximum temperature), which is the firing temperature, for 3 hours. After this, 1
The temperature was lowered to 600 ° C. at a rate of 00 ° C./hr and cooled to room temperature to obtain a sintered body chip.

Next, a conductive paste composed of silver, glass frit and vehicle is applied to the end surface of the sintered body chip from which the internal electrodes are exposed and dried. At this time, diffusion occurs between the internal electrode and the portion of the external electrode that contacts the internal electrode.

After that, this was baked in air at a temperature of 800 ° C. for 15 minutes to form a pair of external electrodes by providing a silver electrode layer, and the above-mentioned laminated capacitor was obtained.

According to the above-mentioned multilayer capacitor, the external electrode 34, which is in contact with the end portion of the internal electrode 32, has the discolored portion 34a which is discolored corresponding to the position where the internal electrode 32 is formed. Since the formation position of the internal electrode 32 can be easily recognized from the above, it is possible to easily find the stacking deviation of the internal electrode 32 and the like.
Even in the multilayer capacitor in which the bias is uneven, the bias of the internal electrode 32 can be easily identified.

Next, a second embodiment of the present invention will be described. FIG. 8 is an external perspective view showing the multilayer capacitor of the second embodiment, and FIG. 9 is a side sectional view thereof. In the figure, the same components as those of the first embodiment described above are designated by the same reference numerals, and the description thereof will be omitted. In addition, the first embodiment and the second
The difference from the above embodiment is that the end portion of the internal electrode 32 is formed so as to project outward from the end surface of the element body 33, and the external electrode 34 of the portion that corresponds to this protruding state and contacts the external electrode 34. Is formed so as to project.

That is, the external electrode formed on the protruding portion of the internal electrode 32 by forming the external electrode 34 on the end portion of the internal electrode 32 protruding outward from the end surface of the element body 33. 34 is also in a protruding state, and a protruding portion 34b is formed.

Further, in order to project the end portion of the internal electrode 32 to the outside of the end surface of the element body 33, the contraction rate of the dielectric layer 31 constituting the element body 33 at the time of firing and the contraction rate of the internal electrode 32 are set. By making them different, the ends of the internal electrodes 32 can be easily formed in a protruding state.

The above-mentioned internal electrode 32 is made of a metal thin film obtained by sintering a thin film of a conductive paste, and as the conductive paste, for example, one containing palladium powder as a main component is used. The external electrode 34 is also made of the same material as the internal electrode 32.

This multilayer capacitor was manufactured as follows. First, an organic binder was added to the dielectric raw material powder.
% By weight, and further 50% by weight of water, and these were put into a ball mill and mixed well to prepare a slurry of a dielectric ceramic raw material.

Next, after putting this slurry in a vacuum defoamer to defoam it, put it in a reverse roll coater to form a thin film of this slurry on the polyester film,
This thin film is dried by heating to 100 ° C. on a polyester film, punched out, and 10 cm square, about 2 mm thick.
A green sheet of 0 μm was obtained.

On the other hand, 10 g of palladium powder having an average particle diameter of 1.5 μm and 0.9 g of ethyl cellulose dissolved in 9.1 g of butyl carbitol were placed in a stirrer,
By stirring for 10 hours, a conductive paste for an internal electrode was obtained.

After that, the internal electrode pattern described above is applied to 5
Using each of the screens having zero, a pattern of the internal electrode made of the conductive paste was printed on one surface of the green sheet, and dried.

Next, a plurality of green sheets were laminated with the printing surface facing upward, and further, unprinted green sheets were laminated on the upper and lower surfaces of this laminate. Then
This laminate was pressed at a temperature of about 50 ° C. by applying a pressure of about 40 tons in the thickness direction. Thereafter, the laminate was cut into a lattice to obtain about 50 laminated chips.

Next, this laminated chip is placed in a furnace capable of firing in an atmosphere and heated to 600 ° C. in the atmosphere to fire the organic binder, and thereafter, the atmosphere of the furnace is set to the atmosphere in the atmosphere to heat the laminated chip. The temperature was maintained at 600 ° C. to 1150 ° C. (maximum temperature), which is the firing temperature, for 3 hours. After this, 1
The temperature was lowered to 600 ° C. at a rate of 00 ° C./hr and cooled to room temperature to obtain a sintered body chip.

At the time of this firing, the end portions of the internal electrodes 32 can be projected outward from the end faces of the sintered body chips (element body 33) due to the difference in shrinkage between the dielectric layer and the internal electrodes.

Next, a conductive paste composed of silver, glass frit and vehicle is applied to the end surface of the sintered body chip where the internal electrodes are exposed and dried. At this time, the protruding portion of the internal electrode has a shape corresponding to this.

After that, this is baked in the atmosphere at a temperature of 800 ° C. for 15 minutes to form a silver electrode layer, and copper is further deposited thereon by electroless plating, and Pb-is formed on the silver electrode layer by electroplating. Providing a Sn solder layer to form a pair of external electrodes,
The multilayer capacitor described above was obtained.

According to the multilayer capacitor having the above-described structure, the end portion of the internal electrode 32 projects outward from the end surface of the element body 33, and the external electrode 34 is formed such that the portion corresponding to the projecting portion of the internal electrode 32 projects. Since it is possible to easily recognize the formation position of the internal electrode 32 from the outside, it is possible to easily find the stacking deviation of the internal electrode 32, etc., and in the capacitor in which the internal electrode 32 is biased. Can also easily identify the deviation of the internal electrodes 32.

These embodiments are merely examples, and the present invention is not limited to these.

[0042]

As described above, according to the multilayer capacitor of the first aspect of the present invention, the external electrode in contact with the end of the internal electrode is discolored corresponding to the position where the internal electrode is formed. Therefore, it is possible to easily recognize the formation position of the internal electrode from the outside, so that it is possible to easily find the stacking deviation of the internal electrode and the unevenness of the internal electrode even in a capacitor in which the internal electrode is biased. It can be easily identified.

Further, according to the multilayer capacitor of claim 2, the end portion of the internal electrode is projected outward from the end face of the element body, and the external electrode is formed by projecting a portion corresponding to the protruding portion of the internal electrode. Since it is possible to easily recognize the formation position of the internal electrode from the outside, it is possible to easily find the stacking deviation of the internal electrode, and also in the capacitor in which the internal electrode is biased, Bias can be easily identified.

[Brief description of drawings]

FIG. 1 is an external perspective view showing a multilayer capacitor according to a first embodiment of the present invention.

FIG. 2 is an exploded perspective view showing a conventional multilayer capacitor.

FIG. 3 is a cross-sectional plan view showing a conventional multilayer capacitor.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a diagram illustrating a problem in a conventional example.

FIG. 6 is a diagram illustrating a problem in a conventional example.

FIG. 7 is a side sectional view showing the multilayer capacitor according to the first embodiment of the present invention.

FIG. 8 is an external perspective view showing a multilayer capacitor according to a second embodiment of the present invention.

FIG. 9 is a side sectional view showing a multilayer capacitor according to a second embodiment of the present invention.

[Explanation of symbols]

30 ... Multilayer capacitor, 31 ... Dielectric layer, 32 ... Internal electrode, 33 ... Element body, 33a ... Recessed portion, 34 ... External electrode, 34
a ... discolored portion, 34b ... protruding portion.

Claims (2)

[Claims] 1. A substantially rectangular parallelepiped element body in which dielectric layers and internal electrode layers are alternately laminated, and an interior formed in the internal electrode layer so as to cover the end faces at both ends of the element body. A multilayer capacitor comprising a pair of external electrodes in which electrodes are alternately connected in parallel, wherein the external electrode in contact with the internal electrode end is discolored corresponding to the position where the internal electrode is formed. A multilayer capacitor characterized in that 2. A substantially rectangular parallelepiped element body formed by alternately laminating dielectric layers and internal electrode layers, and an interior formed in the internal electrode layer so as to cover the end faces at both ends of the element body. A multilayer capacitor comprising a pair of external electrodes in which electrodes are alternately connected in parallel, wherein an end of the internal electrode projects outward from an end surface of the element body, and the external electrode is the internal electrode. A multilayer capacitor, wherein a portion corresponding to the protruding portion of is formed so as to protrude.