JPH07192966A - Ceramic capacitor - Google Patents

Abstract

PURPOSE:To provide a ceramic capacitor in which the influence of a physical stress applied to a laminated ceramic capacitor can be reduced as far as possible after being mounted on a circuit board, in which damage due to a crack, an exfoliation or the like is not caused in the laminated capacitor and whose reliability is high. CONSTITUTION:A plurality of chip ceramic capacitors 1 in which external electrodes 2, 3 have been formed on both end parts are juxtaposed so as to be adjacent by making their directions uniform. The adjacent external electrodes 2, 3 are connected electrically by a flexible conductive resin 7. Adjacent parts in which the external electrodes 2, 3 are not installed are connected mechanically by a flexible insulating resin 8. The external electrodes 2 which have been formed of a solderable material out of the opposite external electrodes 2, 3 are situated in mutually diagonal positions.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a chip type ceramic capacitor which is directly soldered to a circuit board.

[0002]

2. Description of the Related Art With the miniaturization and high speed digitalization of electronic equipment, there is a strong demand for miniaturization and high speed digitalization of electronic parts used in these electronic equipment. Therefore, also in capacitors which are typical of electronic parts, chip-type ceramic capacitors using a ceramic dielectric, for example, chip-type multilayer ceramic capacitors which are small and have a large capacity and excellent in high frequency characteristics are often used.

This chip type monolithic ceramic capacitor has a multi-layer dielectric ceramic body composed of a plurality of dielectric ceramic layers and a plurality of internal electrode layers laminated on each other via the dielectric ceramic layers. External electrodes are formed that are connected to predetermined ones of the internal electrodes.
The mounting on the circuit board is performed by directly joining the external electrodes 2 of the chip type monolithic ceramic capacitor 1 and the conductor portions 6 of the circuit board 5 with solder 4 as shown in FIG.

[0004]

Such a chip-type monolithic ceramic capacitor is not flexible because its main constituent material is ceramic. Therefore, the mounted ceramic capacitor is easily affected by physical stress such as expansion and contraction of the circuit board due to bending and thermal stress, and cracks C and the like occur as shown in FIG. 5 to damage the ceramic capacitor. There was an occasion. This kind of destruction is a chip type ceramic capacitor instead of a tantalum electrolytic capacitor or an aluminum electrolytic capacitor.
This often occurred when a large-capacity, large-sized chip type multilayer ceramic capacitor was used by taking advantage of high frequency characteristics and non-polarity.

As measures against this, it has been attempted to reduce the amount of solder used when soldering to a circuit board as much as possible to suppress the stress applied to the chip type multilayer ceramic capacitor through the solder. However, this method is difficult to maintain a constant amount of solder with good reproducibility during mass production. On the other hand, if the amount of solder is too small, the adhesion may be insufficient and the reliability of the connection may worsen. Not a good solution.

Therefore, an object of the present invention is to minimize the effect of physical stress applied to a chip type ceramic capacitor after mounting on a circuit board, and to prevent damages such as cracks and peeling, and to improve reliability. It is to provide a ceramic capacitor having high performance.

[0007]

In order to achieve the above object, the ceramic capacitor of the present invention has a plurality of chip-type ceramic capacitors having external electrodes formed at both ends thereof, which are arranged side by side in the same direction. The adjacent external electrodes are electrically connected with a conductive resin having flexibility,
Adjacent parts not provided with external electrodes were mechanically joined with a flexible insulating resin, and the external electrodes formed of a material with solder among the opposing external electrodes were positioned diagonally to each other. It is characterized by

[0008]

The ceramic capacitor of the present invention is formed by adjoining a plurality of ceramic capacitors adjacent to each other with a flexible resin, and the external electrodes soldered to the circuit board are:
It is formed so as to be positioned diagonally to each other in the joined ceramic capacitors. Therefore, after mounting on the circuit board, even if the ceramic capacitor is stressed through the soldered part due to deflection of the circuit board, thermal stress, etc., the flexible resin part to which the ceramic capacitor is bonded is deformed and the stress is reduced. Will be alleviated.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the ceramic capacitor of the present invention will be described below with reference to the drawings by taking a chip type monolithic ceramic capacitor as an example. 1 is a perspective view showing a first embodiment, and FIG. 2 is a perspective view showing a state in which the ceramic capacitor of the first embodiment of FIG. 1 is mounted on a circuit board by soldering.

The ceramic capacitor of this embodiment has a structure in which two chip type monolithic ceramic capacitors are adhered to each other. That is, in FIG. 1, 1 is a chip type multilayer ceramic capacitor which is arranged in parallel with each other in the same direction, 2 is an external electrode with solder applied and baked with an electrode paste containing Ag as a main component, and 3 is Pd or the like. It is an external electrode that does not have solder applied and baked with the main component paste. Reference numeral 7 denotes an epoxy-based conductive resin having Ag as a main component and having flexibility, and external electrodes 2 adjacent to each other of two chip type monolithic ceramic capacitors 1.
And the external electrode 3 are joined and electrically connected. Reference numeral 8 denotes an epoxy-based flexible insulating resin, which mechanically joins the two chip type monolithic ceramic capacitors 1.

In the ceramic capacitor thus formed, the external electrodes 2 to which the solder is attached are located diagonally to each other. Therefore, when mounting on the circuit board,
As shown in FIG. 5, only the external electrodes 2 to which the solder is attached, which are diagonally positioned, are soldered to the conductor portion 6 of the circuit board 5.
Moreover, the mounted ceramic capacitors are made up of the conductive resin 7 having flexibility in the two monolithic ceramic capacitors 1.
Also, since the insulating resin 8 having flexibility is bonded, the solder 4 is deformed due to bending of the circuit board 5 or thermal stress.
Even if a stress is applied via, the portions of the conductive resin 7 having flexibility and the insulating resin 8 having flexibility are easily deformed, and the stress is relieved. Therefore, there is no fear that the ceramic capacitor will not be able to withstand stress and cracks or peeling will occur.

The external electrode material of the chip type monolithic ceramic capacitor is not limited to the above embodiment. For example, as an external electrode to which solder is attached, Cu which is conventionally known as an external electrode of a laminated ceramic capacitor is used.
Electrodes, Ni (lower layer) -Sn (upper layer) plated electrodes, solder plated electrodes, or the like can be used. As the external electrode without solder, a Ni-based electrode or a baked electrode containing Ag as a main component and a large amount of glass frit added thereto can be used.

Further, the conductive resin for electrically connecting the external electrodes of the chip type multilayer ceramic capacitor or the insulating resin for bonding the chip type multilayer ceramic capacitor is not limited to the above embodiment. For example,
As the conductive resin having flexibility, Cu or the like can be used as the conductive component in addition to Ag, and the silicon resin or the like can be used as the resin component. Further, as the flexible insulating resin, a silicone resin or the like can be used as well.

Further, the number and direction of the chip type laminated ceramic capacitors to be bonded are not limited to those in the above embodiment, but can be appropriately designed according to the electrostatic capacitance of the ceramic capacitor, the application and the like. Another embodiment will be described below.

FIG. 3 shows a second embodiment, in which three chip type monolithic ceramic capacitors are superposed and joined in the direction of thinness. Since the other parts are the same as those in FIG. 1 which is the first embodiment, the same reference numerals are given and the description thereof will be omitted. Further, FIG. 4 shows a third embodiment in which four chip type monolithic ceramic capacitors are joined. Since the other parts are the same as those in FIG. 1 which is the first embodiment, the same reference numerals are given and the description thereof will be omitted.

In the above embodiments, the case of the chip type multilayer ceramic capacitor as the ceramic capacitor has been described, but the present invention is not limited to this, and is widely applied to the case of a chip type ceramic capacitor. It goes without saying that the effect can be obtained.

[0017]

As is apparent from the above description, according to the ceramic capacitor of the present invention, after being mounted on the circuit board, the ceramic capacitor is subjected to stress through the soldered portion due to the deflection of the board, thermal stress, or the like. Even
It is possible to prevent the stress from being relieved at the flexible resin portion to which the ceramic capacitor is joined and the ceramic capacitor from being damaged such as cracks. Therefore, a highly reliable ceramic capacitor can be obtained.

Further, this effect is particularly remarkable when applied to a large-capacity, large-sized ceramic capacitor as a substitute for the tantalum electrolytic capacitor or the aluminum electrolytic capacitor.

[Brief description of drawings]

FIG. 1 is a perspective view showing a first embodiment of a ceramic capacitor of the present invention.

FIG. 2 is a perspective view showing a state where the ceramic capacitor of the first embodiment is soldered and mounted on a circuit board.

FIG. 3 is a perspective view showing a second embodiment of the ceramic capacitor of the present invention.

FIG. 4 is a perspective view showing a third embodiment of the ceramic capacitor of the present invention.

FIG. 5 is a perspective view showing a state in which a conventional ceramic capacitor is mounted by soldering on a circuit board.

[Explanation of symbols]

 1 Chip Type Multilayer Ceramic Capacitor 2 External Electrode with Solder 3 External Electrode without Solder 4 Solder 5 Circuit Board 6 Conductor of Circuit Board 7 Flexible Conductive Resin 8 Flexible Insulating Resin

Claims (1)

[Claims] 1. A plurality of chip type ceramic capacitors having external electrodes formed on both ends thereof are arranged side by side in the same direction, and the adjacent external electrodes are electrically connected by a conductive resin having flexibility. Connected to each other, and the adjacent parts where no external electrodes are provided are mechanically joined with a flexible insulating resin. A ceramic capacitor characterized by being located at.