JP2008205073A - Ceramic capacitor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the breakage of a ceramic capacitor and the occurrence of short circuit. <P>SOLUTION: The ceramic capacitor includes a lamination 3 made by alternately laminating dielectrics 1 and inner electrodes 2, and a pair of external electrodes 4 and 5 which are disposed to extend at least from both end faces to the mounting surface of the lamination 3 and are connected alternately to the inner electrodes 2. The lamination 3 and the pair of external electrodes 4 and 5 are almost flush with each other on the mounting surface. Inner electrodes 2ba and 2bb of an inner electrode pair 2b that is at least at the outermost position in the lamination direction of the lamination 3 do not overlap the external electrodes 5 and 4 that are not electrically connected to the pair of inner electrodes 2ba and 2bb, respectively, in a view from the lamination direction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a ceramic capacitor used in electronic equipment and the like.

  The configuration of a conventional ceramic capacitor will be described.

  FIG. 5 is a cross-sectional view of a conventional ceramic capacitor. In FIG. 5, a pair of external electrodes 14 are formed on both end surfaces of a laminated body 13 formed by alternately laminating internal electrodes 11 and dielectric layers 12, and the internal electrodes 11 are formed of the pair of external electrodes. 14 and the ceramic capacitor 15 are electrically connected alternately.

  Due to the recent miniaturization of electronic devices, ceramic capacitors are also required to be miniaturized. In the case of downsizing the ceramic capacitor 15 described above, a method of thinning the dielectric layer 12, the internal electrode 11, and the external electrode 14 can be considered. However, when the size is simply reduced by this method, the printed circuit board or the like is used. When mounting, the ceramic capacitor may be damaged.

  That is, the step between the laminated body 13 and the external electrode 14 is not lost even if the external electrode 14 is thinned, and the strength is reduced by thinning the laminated body. The capacitor may be damaged.

  Here, at least the external electrode on the mounting surface is pushed into the laminated body side so that the external electrode and the laminated body are flush with each other, so that the above-described step can be eliminated, so that the damage can be reduced.

Patent Document 1 is known as prior art document information related to the invention of the present application.
JP 2006-332601 A

  However, when the external electrode on the mounting surface is pushed into the laminated body, the distance between the electrodes of the internal electrode portion that overlaps the external electrode when viewed from the stacking direction becomes narrow, and as a result, there is a problem that short-circuiting easily occurs.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to reduce the occurrence of a short circuit while reducing breakage of a ceramic capacitor.

  In order to achieve this object, the present invention provides a laminate in which dielectrics and internal electrodes are alternately laminated, and a pair of external electrodes provided alternately from at least both end faces to the mounting surface of the laminate and connected to the internal electrodes. In the ceramic capacitor having an electrode, the laminate and the pair of external electrodes are substantially flush with each other on the mounting surface, and each of the pair of internal electrodes at least at the outermost position in the stacking direction of the laminate, Each of the pair of internal electrodes and each of the external electrodes that are not electrically connected do not overlap each other when viewed from the stacking direction.

  According to the configuration of the present invention, since the laminate and the pair of external electrodes are substantially flush with each other on the mounting surface, a step between the laminate and the external electrode on the mounting surface can be suppressed. Breakage of the ceramic capacitor due to mechanical stress can be reduced.

  In addition, each of the pair of internal electrodes at least at the outermost position in the stacking direction of the stacked body and each of the external electrodes that are not electrically connected to the pair of internal electrodes at the outermost position do not overlap each other when viewed from the stacking direction. By doing so, the occurrence of a short circuit can be suppressed.

  In other words, when the external electrode on the mounting surface is pushed into the laminate as in the conventional configuration, the distance between the electrodes of the internal electrode that overlaps the external electrode as viewed from the stacking direction becomes narrow, and a short circuit occurs in this portion. Although it was easy to generate | occur | produce, according to the structure of this invention, since the internal electrode part in which this distance between electrodes becomes narrow is lost, generation | occurrence | production of a short circuit can be suppressed.

  Hereinafter, a ceramic capacitor of the present invention will be described with reference to an embodiment and drawings.

  FIG. 1 is a perspective view of a ceramic capacitor of the present invention, FIG. 2 is a sectional view thereof, and FIG. 3 is an exploded perspective view of the laminate.

  1 to 3, a dielectric 3 and internal electrodes 2 are alternately laminated to constitute a laminate 3. External electrodes 4 and 5 are formed on both end surfaces of the laminate 3, and the internal electrodes 2 are electrically connected to the external electrodes 4 and 5 alternately. The external electrodes 4 and 5 and the laminated body 3 are substantially flush with each other on the mounting surface (in this embodiment, the surface facing the mounting surface).

  In addition, the pair of inner electrodes 2b at the outermost position in the stacking direction is formed shorter in the longitudinal direction than the pair of inner electrodes 2a positioned at the center in the stacking direction, so that the pair of inner electrodes 2b at the outermost position. The external electrodes that are electrically connected to the external electrodes (electrically non-connected external electrodes) facing each other are not overlapped when viewed from the stacking direction. That is, in FIG. 2, line A indicates a line drawn from the end of the external electrode 5 in the stacking direction, and the internal electrode 2ba that is not connected to the external electrode 5 among the pair of internal electrodes 2b at the outermost position is the A Form so as not to cross the line. The same applies to the other internal electrode 2bb.

  By configuring the internal electrodes in this way, the distance between the electrodes of the internal electrode portion that overlaps with the external electrode when viewed from the stacking direction can be secured to the same level as the distance between the electrodes of the internal electrode portion that does not overlap with the external electrode, As a result, occurrence of a short circuit can be suppressed.

  That is, the ceramic capacitor of the present invention is characterized in that the distance between the electrodes of the internal electrode is constant between the portion that overlaps the external electrode and the portion that does not overlap when viewed from the stacking direction.

  As described above, the ceramic capacitor of the present invention includes a laminated body in which dielectrics and internal electrodes are alternately laminated, and a pair of external electrodes provided alternately from at least both end faces to the mounting surface of the laminated body and connected to the internal electrodes. In the ceramic capacitor having an electrode, the stacked body and the pair of external electrodes are substantially flush with each other on a mounting surface, and one of at least the outermost pair of internal electrodes in the stacking direction of the stacked body. An internal electrode and an external electrode that is not connected to one internal electrode are not overlapped when viewed from the stacking direction, and the other internal electrode of the pair of internal electrodes at the outermost position is not connected to the other internal electrode The external electrodes are configured not to overlap each other when viewed from the stacking direction.

  As a method for manufacturing the ceramic capacitor 6 of the present invention, a conventional manufacturing method can be used. That is, a ceramic green sheet and internal electrodes are alternately laminated to form a pre-fired laminate. At this time, as shown in FIG. 3, the pattern of the internal electrode 2 may be changed between the internal electrode 2b at the outermost position and the internal electrode 2a at the non-outermost position.

  As shown in FIG. 2, in the pre-fired laminate produced with such an internal electrode configuration, a step B caused by the outermost internal electrode 2 b is formed by pressing during lamination. Therefore, an external electrode is formed using this step B. That is, the step B is formed so as to be filled with an electrode paste from both end faces to the mounting surface of the laminate before firing so as to become external electrodes after firing, and is dried. Thereby, the laminate and the external electrode can be substantially flush with each other on the mounting surface. As a result, the step between the laminate and the external electrode is suppressed, so that damage to the ceramic capacitor due to mechanical stress during mounting can be reduced.

  Moreover, you may press the laminated body in which the external electrode was formed in the lamination direction as needed before baking. Thereby, a laminated body and an external electrode can be made more flush with a mounting surface.

  Next, the laminated body in which the external electrode is formed can be fired to obtain the ceramic capacitor of the present invention.

  As described above, the production of the ceramic capacitor of the present invention does not require use of a new manufacturing apparatus, and a conventional manufacturing apparatus can be used. In addition, conventional materials can be used for each material used in each configuration.

  As another embodiment, as shown in FIG. 4, it is also possible to provide a waste electrode 7 not connected to the external electrodes 4 and 5 on the outer side (stacking direction side) of the outermost internal electrode 2b. It is. By providing the discarded electrode 7 in this manner, the stacked body and the external electrode are flush with each other on the mounting surface while keeping the distance between the internal electrodes constant between the portion overlapping the external electrode and the portion not overlapping when viewed from the stacking direction. can do. Also, in the manufacturing method, the electrode pattern can be changed and discarded as the electrode 7 without adding a new process, and there is an advantage that it can be carried out easily.

  In the above-described embodiment, the configuration in which the pair of internal electrodes at the outermost position is shortened in the longitudinal direction has been described. However, the internal electrode having such a configuration is not limited to the outermost position, but immediately The pair of internal electrodes located in the inner layer can also be configured similarly. 2 and 3, the pair of inner electrodes at the outermost position and the pair of internal electrodes located immediately in the inner layer are shortened in the longitudinal direction, and the pair of inner electrodes at the outermost position are shortened in the longitudinal direction in FIG. 4. did. What is necessary is just to set the number of the internal electrodes of such a structure suitably according to the thickness of an external electrode, the thickness of an internal electrode, and the thickness of a dielectric material.

  The present invention is characterized by improved mechanical stress resistance and short-circuit resistance, and is useful for electronic devices and the like.

The perspective view of the ceramic capacitor in one embodiment of this invention Cross section Exploded perspective view of the same laminate Cross section Cross-sectional view of a conventional ceramic capacitor

Explanation of symbols

1 Dielectric 2, 2a, 2b, 2ba, 2bb Internal electrode 3 Laminate 4, 5 External electrode 6 Ceramic capacitor 7 Discarded electrode

Claims (1)

In a ceramic capacitor having a laminate in which dielectrics and internal electrodes are alternately laminated, and a pair of external electrodes that are provided from at least both end faces of the laminate to the mounting surface and are alternately connected to the internal electrodes, the laminate and The pair of external electrodes are substantially flush with each other on the mounting surface, and are electrically unconnected to each of the pair of internal electrodes at least at the outermost position in the stacking direction of the stacked body. A ceramic capacitor characterized in that each of the external electrodes of the ceramic capacitor does not overlap when viewed from the stacking direction.

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