JPH0298912A - Metallized film capacitor - Google Patents

Abstract

PURPOSE:To stabilize a characteristic of a capacitor by a method wherein, in a layer part not contributing to formation of a capacitance, a metallized film is used as a film which does not contribute to the capacitance in order to increase a mechanical connection strength between an end part of the layer part and a flame-sprayed metal electrode. CONSTITUTION:Layer parts 6, 7 not contributing to formation of a capacitance are constituted while they are laminated and united on both sides in a laminate direction of a layer part 1 contributing to formation of the capacitance in such a way that, in a metallized film 11 where a metal film 9 is evaporated and formed as one face of a dielectric film 8 and, in addition, a margin 10 is formed for dielectric isolation between electrodes, the margin is situated substantially in an identical position in the laminate direction. Accordingly, the metal film 9 on the dielectric film 8 does not contribute to formation of the capacitance. When the metallized film 11 is used as a reinforcement film, a mechanical connection strength between end parts of both layer parts of a laminate and flame-sprayed metal electrodes is increased; a characteristic of a capacitor can be stabilized.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention This invention relates to metallized film capacitors.

BACKGROUND OF THE INVENTION First, an example of a conventional metallized film capacitor will be described with reference to FIG.

In FIG. 4, 41 is a layer portion that contributes to the formation of capacitance, and as shown in FIG. 4 (bl), a dielectric film 42
A metal film 43 is deposited on top of the metal film 43, and a non-metallic part (hereinafter referred to as margin) is formed to form capacitance thereon.
Metalized films 45 having 44 formed thereon are alternately laminated and integrated such that the odd numbered films are located on one edge side and the even numbered films are located on the other edge side.

46.47 is a layer portion that does not contribute to capacitance formation,
Films 48 that do not have a metal film are laminated and integrated on both sides of the layer portion 41 that contributes to the formation of capacitance in the lamination direction.

Reference numerals 49 and 50 designate sprayed metal electrodes, which are formed on both end faces of the laminate so as to be connected to every other metal film 43 of the layer portion 41 that contributes to the formation of capacitance.

In such a metallized film capacitor, the electrical contact between the metal film 43 and the sprayed metal electrodes 49 and 50 is more likely to be unstable near the outermost layer in the stacking direction than in the middle layer. Therefore, if the outermost layer is used as a layer that contributes to capacitance formation in order to stabilize the electrical contact state, the dielectric loss tangent characteristic near the outermost layer becomes unstable, and the dielectric loss tangent of the entire capacitor element becomes unstable. Characteristics and even capacitance accuracy deteriorate.

For this reason, conventionally, layer parts 46 and 47 in which films 48 on which no metal film is deposited are laminated on both sides of the layer part 41 that contributes to the formation of capacitance as described above, and A lacquered film coated with a lacquer layer was integrally laminated on both sides of the layer portion 41 contributing to the formation of capacitance, thereby protecting and reinforcing the layer portion 41.

Problems to be Solved by the Invention However, when a film without a metal film or a lacquered film is used as a reinforcing film, when metal is thermally sprayed on the end face of the laminate, the metallized film becomes 8I.
Compared to the intermediate layer portion 41 with the II layer, in the layer portions 46 and 47 where films without a metal film are laminated, the degree of penetration of the solvent metal into the entire layer is lower. This is because the sprayed metal has a strong bond with the vapor-deposited metal film 43 on the metallized film 45, so the sprayed metal easily penetrates between the layers in the intermediate layer portion 41, resulting in a strong surface contact state. On the other hand, in the layer portions 46 and 47 that do not have a vapor-deposited metal film, it is difficult for the sprayed metal to penetrate between the layers.

In this way, the portions 46 on both sides of the capacitor element in the stacking direction
．． 47, the mechanical contact strength with the sprayed metal electrode 49.50 is very weak compared to the intermediate layer portion 41;
This causes a problem in that the mechanical contact strength of the capacitor element as a whole decreases.

In addition to the above-mentioned problems, capacitor elements are constructed by laminating two films with different heat shrinkage rates: a metallized film with a metal film and a film without a metal film, so aging treatment and soldering are difficult. When thermal treatment such as bonding is applied, stress is generated inside the capacitor element, which may cause characteristic deterioration.

In view of the above problems, the present invention improves the mechanical strength of the capacitor element as a whole by increasing the mechanical contact with the sprayed metal electrode even in layer portions that do not contribute to capacitance formation.
Another object of the present invention is to provide a metallized film capacitor having a structure that does not generate stress even when subjected to thermal treatment.

Means for Solving the Problems The metallized film capacitor of the present invention includes a first metallized film laminate portion forming a capacitance, and a first metalized film laminate portion forming a capacitance.
A laminate consisting of second and third metallized film laminate parts that do not contribute to capacitance formation, which are integrated on both sides of the metallized film laminate part in the lamination direction, and this laminate. The second and third metallized film laminated portions are composed of a plurality of metalized films in which a non-metalized portion is formed to electrically isolate the electrodes. and the metallized films are laminated so that the non-metalized portions are located at approximately the same position.

Effect: With this configuration, the metallized film capacitor of the present invention allows the sprayed metal to easily come into contact with the vapor-deposited metal on the metallized film, so that it penetrates between the metallized film layers and comes into surface contact with the vapor-deposited electrode. Therefore, it is possible to strengthen the mechanical connection strength of the sprayed metal electrode even in the laminated portion of the metallized film that does not contribute to the formation of capacitance. Furthermore, since all layers are made of the same metallized film and have a single thermal shrinkage rate, there is no possibility of internal stress occurring even when heat is applied.

Examples Examples of the metallized film capacitor according to the present invention will be described below with reference to the drawings.

[Embodiment 1] Figure 1 (al is a perspective view of the first embodiment of the present invention, and figure f is a perspective view of the first embodiment of the present invention.
b) is an exploded perspective view showing the laminated structure of the main part thereof.

In the figure, 1 is a layer portion that contributes to the formation of capacitance, and as shown in the figure (bl), a metal film 3 is deposited on one surface of the dielectric film 2, and further forms a capacitance thereon. As in the conventional example shown in FIG.
are laminated and integrated so that they are alternately located on opposite edge sides.

6.7 is a layer portion that does not contribute to the formation of capacitance, and a metal film 9 is formed by vapor deposition on one surface of the dielectric film 8;
Furthermore, a metallized film 11 is formed with a margin 10 for insulating and separating between electrodes, which will be described later.
As shown in FIG. 1, the layer portions 1 contributing to capacitance formation are laminated and integrated on both sides in the lamination direction so that the margins 10 are at substantially the same position in the lamination direction.

Due to this laminated state, the metal film 9 on the dielectric film 8 does not contribute to the formation of capacitance.

Denoted at 12 and 13 are sprayed metal electrodes, which are formed on the end faces of the laminated layer so as to be electrically connected to every other metal film 3 of the layer portion 1 that contributes to the formation of capacitance.

According to this embodiment, since the metallized film is used as the reinforcing film, the layer portions 46, 47 on both sides of the laminate
The mechanical connection strength between the end of the metal electrode and the sprayed metal electrode can be increased.

However, in this prior art example, since a metallized film with a narrow single margin is used as a reinforcing film, each monolayer of layer portions 46, 47 is very closely aligned in its machine position relative to each other. If the layers are not laminated with high precision, there is a risk that parasitic capacitance will occur in the misaligned portions.

Such constraints on position accuracy will be resolved in the following second and third embodiments.

[Embodiment 2] FIG. 2 (al is a perspective view of this embodiment, and FIG. 2 (bl is an exploded perspective view showing the laminated structure of the main part thereof.

The biggest difference between Example 2 and Example 1 is that the margin 2 of the layer portion 6.7 that does not contribute to the formation of capacitance is made wider.

With this structure, the first embodiment can prevent the generation of parasitic capacitance regardless of the positional accuracy in lamination.

[Embodiment 3] FIG. 3(a) is a perspective view of this embodiment, and FIG. 3(b) is an exploded perspective view showing the laminated structure of the main part.

Embodiment 3 differs from Embodiment 1.2 in that there are a plurality of margins 2 in the layer portions 6.7 that do not contribute to the formation of capacitance.

Since the metal film 9 of the layer portion 6.7 is provided with the margins 10 that divide the electrodes into a plurality of parts, as long as a sufficient distance is provided between the margins 10, even if the margin width is narrow, the embodiment 1 can prevent the generation of parasitic capacitance without requiring any precision.

Effects of the Invention According to the metallized film of the present invention, since the layer portion that does not contribute to capacitance formation is constructed using the metallized film as a film that does not contribute to capacitance, the end portion of this layer portion and the thermal spraying The mechanical contact strength with the metal electrode can be increased, and stable capacitor characteristics can be obtained. Furthermore, since the coefficients of thermal expansion of the film layers constituting the capacitor are substantially the same, no stress is generated inside the capacitor due to heat, and deterioration of characteristics can be reduced.

[Brief explanation of the drawing]

FIG. 1 (Al is a perspective view showing the structure of the first embodiment of the metallized film capacitor according to the present invention, and FIG. 1B is an exploded perspective view showing the laminated structure of the main part. 131 is a perspective view of a main part of a second embodiment of the metallized film capacitor according to the present invention, and FIG. 3(b) is an exploded perspective view showing the laminated structure of the main part. FIG. 4 (al) is a perspective view of the main parts of the third embodiment of the metallized film capacitor according to the third embodiment, and FIG. A perspective view of a main part showing an example (bl is an exploded perspective view showing a laminated structure of the main part. 1... Layer portion contributing to capacitance formation 2...
...Dielectric film, 3...Metal film, 4...
...Margin for forming capacitance, 5...
... Gold rR film, 6.7 ... Layer portion that does not contribute to capacitance formation, 8 ... Dielectric film, 9 ... Metal film, 10. ...margin, 11...gold III film. Name of agent: Patent attorney Shigetaka Awano and one other person

Claims (2)

[Claims] (1) A first metallized film laminated portion that forms capacitance, and a first metallized film laminated portion that does not contribute to capacitance formation and is integrated on both sides of the first metallized film laminated portion in the lamination direction. 2. A laminate comprising a third metallized film laminate portion and a pair of electrodes provided to the laminate, wherein the second and third metallized film laminate portions are It consists of multiple metalized films with non-metalized parts that provide electrical isolation between the electrodes.
The metallized film capacitor is characterized in that the metallized films are laminated so that their non-metalized portions are located at substantially the same position. (2) The metallized films of the second and third metallized film laminated portions have a plurality of non-metalized portions, and the metallized films are laminated so that the plurality of non-metalized portions overlap. A metallized film capacitor according to claim 1, characterized in that: