JPH09260204A - 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: This device 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. Upper and lower surfaces 33a of the element assembly 33 parallel to the inside electrode 32 are formed into a rough surface and a laminated capacitor 30 whose side surface 33b is formed into a bright surface is constituted. Since a plane direction of the inside electrode 32 can be thereby readily recognized from the outside, the mounting state of a capacitor on a circuit board can be discriminated even when it is used for a high-frequency circuit and a desired electrostatic capacity can be obtained.

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 plane direction or the formation position of the internal electrode 12 cannot be discriminated from the outside, and when it is used in a high frequency circuit, in particular, a circuit board is formed. The capacitance of the capacitor may vary greatly depending on the mounting state of the capacitor, that is, the multilayer capacitor 10 so that the circuit board 20 and the internal electrode 12 are parallel to each other as shown in FIG.
Stray capacitance is generated between them when mounted, and when the multilayer capacitor 10 is mounted so that the circuit board 20 and the internal electrode 12 are vertical as shown in FIG. It is different from the above.

Therefore, the capacitance obtained varies depending on how the multilayer capacitor 10 is mounted on the circuit board 20.

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

[0010]

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 comprising a pair of external electrodes, which are alternately connected in parallel to the internal electrodes formed on the internal electrode layers so as to cover the end faces at both ends of the body, and are substantially parallel to the internal electrode faces. A multilayer capacitor is proposed in which the upper and lower surfaces of the element body are formed as rough surfaces, and the side surfaces of the element body that are substantially perpendicular to the internal electrode surface are formed as glossy surfaces.

According to the multilayer capacitor, the upper and lower surfaces of the element body substantially parallel to the inner electrode surface are formed as rough surfaces, and the side surfaces of the element body substantially perpendicular to the inner electrode surface are formed as glossy surfaces. Therefore, the plane direction of the internal electrode can be recognized by the surface roughness of the upper and lower surfaces and the side surfaces of the element body.

According to a second aspect of the present invention, in the multilayer capacitor according to the first aspect, the external electrode of the other external electrode is formed so that a position corresponding to a center layer of the internal electrode on the side surface of the element body is substantially an apex. We propose a multilayer capacitor formed so as to project in the electrode direction.

According to the multilayer capacitor, the external electrode is formed so as to project toward the other external electrode so that the position corresponding to the center layer of the internal electrode on the side surface of the element body is substantially the apex. The shape of the external electrode also allows the upper and lower surfaces of the element body to be distinguished from the side surfaces, and this also allows the planar direction of the internal electrode to be recognized.

According to a third 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 are alternately connected in parallel to each other, the internal capacitor being opposed to at least an internal electrode side edge portion of at least a side surface of the element body substantially perpendicular to the internal electrode surface. We propose a multilayer capacitor in which the part to be formed is on the glossy surface.

According to the multilayer capacitor, the side surface of the element body that is substantially perpendicular to the internal electrode surface has the glossy surface at the portion facing the internal electrode side edge portion. The formation position can be recognized.

According to a fourth aspect of the present invention, in the multilayer capacitor according to the third aspect, the external electrode is formed with a protrusion protruding toward the other external electrode on a glossy side surface of the element body. To propose.

According to the multilayer capacitor, since the external electrode is provided with the protruding portion protruding toward the other external electrode on the glossy surface of the side surface of the element body, the planar direction and the forming position of the internal electrode are also formed by this. Can be recognized.

[0018]

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 partially cutaway plan view thereof. In the figure, reference numeral 30 denotes a multilayer capacitor, which includes an element body 33 in which dielectric layers 31 and internal electrodes 32 are alternately laminated, and internal electrodes 32 at both ends of the element body 33.
And a pair of external electrodes 34 that are alternately connected in parallel.

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, the upper and lower surfaces 33a of the element body 33 are formed to be rough surfaces, the side surfaces 33b are formed to be glossy surfaces, and the external electrodes 34 are formed on the side surfaces 33b of the element body 33 at the internal electrodes 3.
A protruding portion 34a protruding toward the other external electrode is formed so that the position corresponding to the second center layer is substantially the apex. Thereby, the upper and lower surfaces 33a and the side surfaces 33 of the element body 33
The plane direction of the internal electrode 32 can be recognized by the surface roughness of b and the shape of the external electrode 34.

The above-mentioned internal electrodes 32 are 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, 15% by weight of an organic binder was added to the raw material powder of the dielectric, 50% by weight of water was further added, and these were put in a ball mill and thoroughly mixed,
A slurry of a dielectric ceramic raw material was prepared.

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 printed 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.

By using a cutter that rotates at high speed during this cutting, the side surface of the laminated chip (element) becomes a glossy surface.

Next, this laminated chip is placed in a furnace capable of firing in an atmosphere and heated to 600 ° C. in the atmosphere to burn the organic binder, and then the atmosphere of the furnace is set 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 where the internal electrodes are exposed and dried. When this conductive paste is applied, the side surface of the sintered body chip (element body) is a glossy surface, so the conductive paste spreads on this glossy surface, and the external electrode is the internal electrode on the side surface of the element body. Is formed so as to protrude toward the other external electrode so that the position corresponding to the center layer of the above becomes substantially the apex.

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 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 above-mentioned multilayer capacitor, the upper and lower surfaces 33a of the element body 33 substantially parallel to the plane of the internal electrode 32 are formed as rough surfaces, and the side surface 33b of the element body 33 substantially perpendicular to the internal electrode surface is a glossy surface. Is formed on the internal electrode 3 due to the surface roughness of the upper and lower surfaces 33a and the side surfaces 33b of the element body 33.
Two plane directions can be recognized. As a result, even when the multilayer capacitor 30 is used in a high frequency circuit, the mounting state of the capacitor on the circuit board can be identified and a desired capacitance can be obtained.

Further, since the external electrode 34 is formed so as to project toward the other external electrode so that the position corresponding to the center layer of the internal electrode 32 on the side surface 33b of the element body 33 becomes substantially the vertex, this external electrode is formed. The shape of 34 also allows the upper and lower surfaces 33a and the side surfaces 33b of the element body 33 to be distinguished, and the plane direction of the internal electrode 32 can be recognized very easily.

Further, as shown in the side sectional view of FIG.
Since it is possible to form a short portion of the external electrode 34 that is parallel to the plane of the internal electrode 32 without reducing the contact area between the element body 33 and the external electrode 34 and maintaining a high degree of adhesion between them, It is possible to reduce the stray capacitance generated during the period.

Needless to say, the same effect can be obtained even if the external electrode 34 has the same shape as the conventional one.

Next, a second embodiment of the present invention will be described. FIG. 9 is an external perspective view showing the multilayer capacitor of the second embodiment, and FIG. 10 is a side 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. Further, the difference between the first embodiment and the second embodiment is that only the portion of the side surface 33b of the element body 33 facing the side edge portion of the internal electrode 32 is formed into a glossy surface and the external electrode 34 is formed. Is the side surface 33b of the element body 33.
In the glossy surface, a protruding portion 34a protruding toward the other external electrode is formed.

That is, by cutting so that the element body side surface 33b is formed at a position such that the distance from the side edge portion of the internal electrode 32 is within a predetermined value at the time of manufacture,
As shown in, the pressure P1 applied to the side surface at the position corresponding to the side edge portion of the internal electrode 32 is larger than the pressure P2 applied to the other portion of the side surface 33b. As a result, only the portion of the element body side surface 33b facing the side edge portion of the internal electrode 32 becomes a glossy surface.

During production, when 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, the glossy surface of the side surface of the sintered body chip (element body) is applied. The conductive paste spreads in the area where is, and the external electrode is the side surface 3 of the element body 33.
3b, the protruding portion 34 protrudes toward the other external electrode.
a is formed.

According to the multilayer capacitor having the above-described structure, the side surface 3 of the element body 33 that is substantially perpendicular to the plane of the internal electrode 32.
In 3b, since the portion facing the side edge of the internal electrode 32 is formed into a glossy surface, the internal electrode 32
It is possible to recognize the plane direction and the formation position of. As a result, even when the multilayer capacitor 30 is used in a high frequency circuit, the mounting state of the capacitor on the circuit board can be identified and a desired capacitance can be obtained.

The external electrode 34 has a side surface 3 of the element body 33.
Since the protruding portion 34a protruding toward the other external electrode is formed on the glossy surface of 3b, the upper and lower surfaces 3 of the element body 33 are formed.
Since 3a and the side surface 33b can be easily distinguished, the plane direction and formation position of the internal electrode 32 can be recognized very easily.

Needless to say, the same effect can be obtained even if the external electrode 34 has a shape without the protrusion 34a as in the conventional case.

The above-described first and second embodiments are examples, and the present invention is not limited to this.

[0042]

As described above, according to the multilayer capacitor of the first aspect of the present invention, the upper and lower surfaces of the element body substantially parallel to the internal electrode surface are formed as rough surfaces and are substantially perpendicular to the internal electrode surface. Since the side surface of the element body is formed into a glossy surface,
Since the planar direction of the internal electrodes can be recognized by the surface roughness of the upper and lower surfaces and the side surfaces of the element body, the mounting state of the capacitor on the circuit board can be identified even when used in a high frequency circuit, and the desired Capacitance can be obtained.

According to the multilayer capacitor of the second aspect, in addition to the above effects, the other external electrode is formed so that the position corresponding to the center layer of the internal electrode on the side surface of the element body is substantially the apex. Since the external electrodes are formed so as to project in the direction, it is possible to distinguish the upper and lower surfaces and the side surfaces of the element body by the shape of the external electrodes, and it is very easy to recognize the planar direction of the internal electrodes. can do.

Further, according to the multilayer capacitor of the third aspect, the side surface of the element body which is substantially perpendicular to the internal electrode surface has the glossy surface at the portion facing the internal electrode side edge portion. Since the planar direction and formation position of the internal electrode can be recognized, the mounting state of the capacitor on the circuit board can be identified even when used in a high frequency circuit, and a desired capacitance can be obtained.

Further, according to the multilayer capacitor of the fourth aspect, in addition to the above effects, the external electrode is provided with a protruding portion protruding toward the other external electrode on the glossy surface of the side surface of the element body. Therefore, since it is possible to distinguish the upper and lower surfaces of the element body from the side surfaces, it is possible to very easily recognize the plane direction and the formation position of the internal electrode.

[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 partially cutaway plan view showing the multilayer capacitor according to the first embodiment of the present invention.

FIG. 8 is a side sectional view showing the multilayer capacitor according to the first embodiment of the present invention.

FIG. 9 is an external perspective view showing a multilayer capacitor according to a second embodiment of the present invention.

FIG. 10 is a side view showing the multilayer capacitor of the second embodiment of the present invention.

FIG. 11 is a sectional view showing a multilayer capacitor of a second embodiment of the present invention.

[Explanation of symbols]

30 ... Multilayer capacitor, 31 ... Dielectric layer, 32 ... Internal electrode, 33 ... Element body, 33a ... Upper and lower surface, 33b ... Side surface, 34
... External electrodes, 34a ... Protrusions.

Claims (4)

[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 upper and lower surfaces of the element body substantially parallel to the internal electrode surface are formed into a rough surface, and the internal electrode surface is formed. A side face of the element body substantially perpendicular to the above is formed into a glossy surface, which is a multilayer capacitor. 2. The external electrode is formed so as to project in the direction of the other external electrode so that the position corresponding to the center layer of the internal electrode on the side surface of the element body is substantially the apex. The multilayer capacitor according to claim 1. 3. A substantially rectangular parallelepiped shaped 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 at least a portion of a side surface of the element body which is substantially perpendicular to the internal electrode surface and which faces the inner electrode side edge portion is a glossy surface. A multilayer capacitor, which is characterized by being formed in. 4. The multilayer capacitor according to claim 3, wherein the external electrode is formed with a protruding portion protruding toward the other external electrode on the glossy side surface of the element body.