JPH0684689A - Multilayer capacitor - Google Patents

Abstract

PURPOSE:To suppress fluctuation of capacity at the time of muss-production by providing fine stripe electrodes for suppressing difference in equipotential distribution caused by the difference in position and number of first and second inner electrodes. CONSTITUTION:First inner electrode 2 is formed wider than a second inner electrode 3. Fine stripe electrodes 8 are arranged on the opposite sides of the second inner electrode 3 on same imaginary plane as the second inner electrode 3. The fine stripe electrodes 8 are then connected with an outer electrode 7 connected with the inner electrode 3 while being arranged to be aligned substantially with the side edge of the inner electrode 2 when viewed from the direction normal to the imaginary plane. This constitution suppresses difference in equipotential distribution caused by the difference in position and number of the first and second inner electrodes 2, 3 thus suppressing fluctuation in the capacity of multilayer capacitor at the time of mass-production.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer capacitor having an odd number of internal electrodes.

[0002]

2. Description of the Related Art In a multilayer capacitor, one of a pair of internal electrodes facing each other may be formed with a narrow width in order to prevent a capacitance change due to a pattern shift of the internal electrodes. 12
13 and 14 show a multilayer capacitor of this type. In FIGS. 12 and 13, the first internal electrode 2 provided in the porcelain dielectric 1 is formed wider than the second internal electrode 3. In this example, two wide first internal electrodes 2 are provided and connected to the first external electrodes 5 on the first side surface 4 of the dielectric 1, respectively. The narrow second internal electrode 3 is connected to the second external electrode 7 on the second side surface 6. If the multilayer capacitor is configured in this way, even if a slight pattern shift occurs between the first internal electrode 2 and the second internal electrode 3 during lamination, the first internal electrode 2 and the second internal electrode 3 The area facing each other can be kept constant, and the capacitance does not change.

[0003]

By the way, when a multilayer capacitor as shown in FIG. 12 is mass-produced so as to save material, two types of multilayer capacitors shown in FIGS. 13 and 14 are produced. Since the multilayer capacitor of FIG. 14 is composed of one wide internal electrode 2 and two narrow internal electrodes 3, the equipotential distribution curve between the electrodes is different from that of FIG. As a result, the capacitance values of the two types of multilayer capacitors shown in FIGS. 13 and 14 differ. When the number of laminated internal electrodes is even, the above problem does not occur, but it is necessary to make the number of laminated layers odd because of the required capacity and size.

The reason why the two types of multilayer capacitors shown in FIGS. 13 and 14 are produced will be described below. When manufacturing a multilayer capacitor, a conductive layer pattern for the first internal electrode 2 and a conductive layer pattern for the second internal electrode 3 are formed on the same green sheet using the same screen. It is common to print at the same time. By printing in this way, it is possible to make the first and second internal electrodes 2, 3 have the same thickness and the like, and suppress variations in capacitance. First
And a method of printing the second internal electrodes 2 and 3 at the same time, if a multilayer capacitor having only the structure of FIG.
There is one more green sheet with the second internal electrode 3,
Become uneconomical. Further, if a multilayer capacitor having only the structure of FIG. 14 is manufactured, only one green sheet of the first internal electrode 2 is left, which is uneconomical. Therefore, if all the green sheets are used, the 2
Types of multilayer capacitors arise.

An object of the present invention is to provide a multilayer capacitor which can suppress the variation in capacitance between the two types of multilayer capacitors shown in FIGS. 13 and 14.

[0006]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a dielectric having first and second side surfaces facing each other and an odd number of three or more parallel to each other inside the dielectric. An odd number of internal electrodes respectively provided on the virtual plane of the first internal electrode and a first internal electrode formed on the first side surface and connected to an odd-numbered first internal electrode of the odd number of internal electrodes.
Of the external electrodes and a second external electrode formed on the second side surface and connected to an even-numbered second internal electrode of the odd-numbered internal electrodes. One internal electrode of the first internal electrode and the second internal electrode is formed wider than the other internal electrode, and is located laterally of the other internal electrode in the same virtual plane as the other internal electrode. Strip electrodes are disposed on both sides of the strip electrode, the strip electrode is connected to an external electrode to which the other internal electrode is connected, and the strip electrode is viewed from a direction perpendicular to the virtual plane. The present invention relates to a multilayer capacitor, which is arranged so as to substantially coincide with a side edge of the one internal electrode.

[0007]

FUNCTION AND EFFECT The strip electrode according to the present invention has the function of reducing the difference in equipotential distribution due to the difference in position and number between the first internal electrode and the second internal electrode. For this reason,
It is possible to reduce variations in capacity during mass production.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a multilayer capacitor according to an embodiment of the present invention and a manufacturing method thereof will be described with reference to FIGS.
Similar to the conventional multilayer capacitor of FIG. 12, the multilayer capacitor shown in FIGS. 1 to 6 has a porcelain dielectric 1, two wide first internal electrodes 2 and one narrow second second electrode. Internal electrode 3
And first and second external electrodes 5 and 7 provided on the first and second side surfaces 4 and 6 facing each other.

The three (odd number) internal electrodes 2 and 3 are the first virtual plane on the line AA in FIG. 2, the second virtual plane on the line BB, and the third on the line CC. Are arranged on the virtual plane and. The first, second, and third virtual planes are parallel to each other and also to both main surfaces of the rectangular parallelepiped dielectric 1. 3, 4, and 5 show patterns of the internal electrodes 2, 3 on the first, second, and third virtual planes.

The first internal electrode 2 of the first virtual plane of the line AA and the third virtual plane of the line C-C, that is, the odd-numbered virtual plane is formed in a rectangular shape, and the first wide electrode is wide. It has a width W1. The second internal electrode 3 of the second virtual plane of the line B-B, that is, the even-numbered virtual plane is formed in a rectangular shape and has a narrow second width W2. As is clear from FIG.
The internal electrode 2 and the third internal electrode 3 are arranged so as to have an overlapping portion when viewed from the direction perpendicular to the virtual plane, and both sides of the overlapping area (capacitor effective area) of the second internal electrode 3 The edges are contained within the first inner electrode 2. Therefore, even if the second internal electrode 3 is slightly displaced in the width direction on the virtual plane, it is prevented from protruding from the facing region of the first internal electrode 2, and the capacitance does not change.

However, if the structure is simply a combination of the wide first internal electrode 2 and the narrow second internal electrode 3, FIG.
3 and the variation in capacitance due to the difference in the configuration of FIG. 14 cannot be eliminated. Therefore, in this embodiment, a pair of strip electrodes 8 are provided in parallel to both side edges of the second inner electrode 3 having a small width. The width W3 between the outer edges of the pair of strip electrodes 8 is set to be substantially the same as the width W1 of the first inner electrode 2. Therefore, when the first and second internal electrodes 2 and 3 are ideally stacked, a pair of strip electrodes 8 are formed on both side edges of the first internal electrode 2 as shown in FIG. It is arranged. The strip electrode 8 is the same as the narrow second internal electrode 3 in the second
Is connected to the external electrode 7. Therefore, a correction electric field distribution can be obtained between the strip electrode 8 and the first internal electrode 2. However, the strip electrode 8 is an extremely thin electrode,
Since this area is minute, the electrostatic capacitance based on the facing of the first internal electrode 2 is extremely small. A space (an electrodeless region) larger than the width of the strip electrode 8 and larger than the pattern deviation in the width direction generated during normal capacitor manufacturing is provided between the strip electrode 8 and the narrow second inner electrode 3. Has been. Therefore, the capacitance hardly changes even if the pattern displacement in the width direction of the first and second internal electrodes 2 and 3 occurs.

The strip electrode 8 has a function of eliminating the variation in the capacitance of the capacitors having the two types of structures shown in FIGS. 6 and 7 during mass production of the capacitors. FIG. 6 shows a structure corresponding to FIGS. 2 to 5, which corresponds to FIG. 13 of the related art, and FIG. 7 corresponds to FIG. 14 of the related art. In FIG. 7, a second internal electrode 3 having a narrow width is arranged vertically with a first internal electrode 2 having a wide width, together with a strip electrode 8. As described above, when the green sheet is effectively used, both the capacitors shown in FIGS. 6 and 7 can be obtained. However, the strip electrode 8
Are arranged on both sides of the second inner electrode 3 having a narrow width, the electric field distributions on both side edges of the first and second inner electrodes 2 and 3 are substantially the same, and FIG. The difference in capacitance between the capacitors of No. 7 is reduced.

FIG. 8 and FIG. 9 show in principle an example of a method of manufacturing the capacitors of FIGS. A slurry made of a porcelain material and an organic binder is made, and a long green sheet (unfired porcelain sheet) 10 is made from this slurry by a doctor blade method or the like, and a conductive paste is formed on the green sheet 10 using a screen. By applying, conductive layers 2a, 3a, 8a corresponding to the first and second internal electrodes 2, 3 and the strip electrode 8 are formed. Printing of the conductive paste in the section from P1 to P3 in FIG. 8 is performed simultaneously using one screen. Thereby, the conductive layer 2a,
3a, 8a can be formed uniformly. After this printing is completed, the conductive layers 2a, 3a, 8 having the same pattern as P1 to P3 are formed in the area after P3 using the same screen.
a is repeatedly formed. After printing, P1, P2
, P3 to cut the green sheet 10. As a result, a plurality of first green sheets 11 having the first inner electrode conductive layer 2a and a plurality of second green sheets having the second inner electrode conductive layer 3a and the strip electrode conductive layer 8a are formed. can get.

Next, as shown in FIG. 9, the first and second green sheets 11 and 12 are laminated and the cover green sheet 13 is laminated, and this is pressure-bonded and cut at a position indicated by a broken line. A molded body (raw chip) is obtained, and this is fired, and finally the external electrodes 5 and 7 are formed. When laminated as shown in FIG. 9, the laminated capacitor having the structure shown in FIG. 6 is obtained. Figure 9
Then, while there are two first green sheets 11,
The number of the second green sheets 12 is one. In FIG. 8, the first
Also, since the second green sheets 11 and 12 are formed at the same time, one second green sheet 12 is left. In order to prevent the excess of the second green sheet 12, the capacitor having the laminated structure shown in FIG. 7 is also manufactured.

[0015]

MODIFICATION The present invention is not limited to the above-mentioned embodiments, and the following modifications are possible. (1) As shown in FIG. 10, the narrow second internal electrode 3 and the strip electrode 8 are connected to each other in the vicinity of the external electrode 7 to improve the reliability of connection of the strip electrode 8 to the external electrode 7. Can be improved. (2) As shown in FIG. 11, the second internal electrode 3 having a narrow width is used.
A narrow connecting region 15 may be provided between the effective electrode region 14 and the external electrode 7 so that the projection of the tip 16 of the first internal electrode 2 crosses the connecting region 15. In this case, even if the first and second internal electrodes 2 and 3 are displaced in the left-right direction in FIG. 11, there is little change in the area where they face each other, so there is little change in capacitance. (3) The present invention can be applied to the case where an odd number of first and second internal electrodes 2 and 3 larger than 3 is stacked.

[Brief description of drawings]

FIG. 1 is a perspective view showing a multilayer capacitor of an example.

FIG. 2 is a central vertical cross-sectional view of the capacitor of FIG.

3 is a cross-sectional view taken along the line AA of FIG.

FIG. 4 is a sectional view taken along line BB in FIG.

5 is a cross-sectional view taken along line CC of FIG.

6 is a cross-sectional view taken along the line DD of FIG.

FIG. 7 shows a case where the stacking order of the internal electrodes of FIG. 6 is changed.
It is sectional drawing shown similarly to.

8 is a plan view showing a green sheet having a pattern of a conductive layer for manufacturing the capacitor of FIG.

9 is a cross-sectional view showing a stack of green sheets for manufacturing the capacitor of FIG.

FIG. 10 is a cross-sectional view showing a pattern of internal electrodes of a modified example similar to FIG.

FIG. 11 is a cross-sectional view showing a pattern of internal electrodes of another modified example similar to FIG.

FIG. 12 is a cross-sectional view showing a conventional multilayer capacitor similar to FIG.

13 is a cross-sectional view of a portion corresponding to line EE in FIG.

14 is a cross-sectional view showing a structure in which the stacking order of the internal electrodes of FIG. 13 is changed, similar to FIG.

[Explanation of symbols]

 2 1st internal electrode 3 2nd internal electrode 4 Strip electrode

Claims (1)

[Claims] 1. A dielectric having first and second side surfaces facing each other, and an odd number of internal electrodes provided on three or more odd virtual planes parallel to each other inside the dielectric, respectively. A first external electrode formed on the first side surface and connected to an odd-numbered first internal electrode of the odd-numbered internal electrodes; and an odd-numbered first external electrode formed on the second side surface. A multilayer capacitor having a second outer electrode connected to an even-numbered second inner electrode of the inner electrodes, wherein one of the first inner electrode and the second inner electrode The electrode is formed wider than the other internal electrode, the strip electrodes are arranged on both sides of the other internal electrode in the same virtual plane as the other internal electrode, and the strip electrode is the other of the other internal electrodes. Connected to the external electrode to which the internal electrode is connected The thin strip electrode is arranged so as to substantially coincide with a side edge of the one internal electrode when viewed from a direction perpendicular to the virtual plane.