JPH06231998A - Film capacitor - Google Patents

Abstract

PURPOSE:To provide a film capacitor capable of being higher voltage resistance and small-sized by a method wherein a longitudinal margin in the longitudinal direction and a lateral margin in the width direction are formed in a thin film electrode of vapor deposited film and a margin part is formed on two sides of the vapor deposited film constituting two symmetrical end surfaces other than the contact surface CONSTITUTION:An aluminum thin film 20 part is formed in a polyethylene terephthalate film 19 as a metal thin film electrode by a vacuum vapor deposited method. A region between the aluminum thin film 20 part is partitioned with a longitudinal margin (electrode surface margin) 21 of width 0.2mm or more in the longitudinal D direction (in the electrode surface direction) and a lateral margin (end surface margin) 22 of width 0.2mm or more in the width C direction (in the cutoff surface direction). By using the thus-made vapor deposited film with margins, it is possible to obtain a vapor deposited film constituting a lamination capacitor having the aluminum thin film 20 part; the longitudinal margin 21 part; the aluminum thin film 20 part having a specific shape by cutting off the lateral margin part; and the longitudinal and lateral margins.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a film capacitor which is one of electronic parts, and has a structure of an electric circuit,
Electric equipment for noise prevention of power circuit, starting of motor, etc.
It is often used in the field of equipment.

[0002]

2. Description of the Related Art In recent years, electric and electronic circuits have been remarkably developed and are widely used in various fields regardless of consumer and industrial fields. The electronic parts that make up these electric and electronic circuits are required to have unique characteristics according to the purpose of use. Recently, in order to realize small size of electrical products as well as reliability and safety for the characteristics, downsizing of electronic parts has been achieved. Is required.

The miniaturization of electronic parts has been promoted along with the progress of miniaturization of light weight, thinness and shortness mainly in consumer audio, video equipment and information equipment. In particular, IC-related products have contributed to miniaturization by increasing the degree of integration year by year. Generally, when attempting to downsize electric appliances and equipment, even if some parts are downsized, the purpose cannot be achieved.Therefore, small size and high safety are required even for individual parts, and in recent years resistors, coils, capacitors, etc. Has been miniaturized mainly for electronic circuits.

However, in recent years, there has been a demand for miniaturization of electronic and electric parts used in the industrial field. Among these, there are demands for changes in industrial film capacitors. One of the required changes in the film capacitor is improvement in safety and miniaturization of the shape like other electronic parts.

Most of the film capacitors that have been proposed and supplied so far are mostly of the winding type and the laminating type. There are two winding methods, one that uses a metal foil and the other that uses a metal thin film for the counter electrode.The structure is such that the electrode part and the polymer film that is a dielectric are wound alternately to form a capacitor element. In the laminated method, the capacitor element is formed by alternately laminating the electrode parts and the dielectric.

FIG. 6 (a) shows an example of a conventional winding type film capacitor. A metal thin film electrode 1 formed by a vacuum deposition method on the surface of a long polymer film 2 and a vapor deposition film having a margin portion 2a where the metal thin film electrode 1 is not formed, and a long polymer film 4 of the same shape. A vapor deposition film having a metal thin film electrode 3 formed on the surface by a vacuum vapor deposition method and a margin portion 4a where the metal thin film electrode 3 is not formed is arranged such that the margin portions 2a and 4a are in opposite positions. The two capacitors are wound in a set so that both ends thereof are aligned to form a capacitor element 5. After this,
6 layers of metallikon (metal sprayed) on both ends of the metal thin film electrode 1
The metallicon portion is formed so as to be in contact with the capacitor, and the capacitor is formed by using this metallikon portion as an external lead electrode. 7 is a lead wire. FIG. 6B shows an element configuration diagram of the capacitor shown in FIG.

FIG. 7 shows an example of a laminated type film capacitor. Capacitor element 10 formed by stacking
Metallicon 11 treatment is applied to the opposite ends of the lead wire 1
2 is provided.

FIG. 8 shows an example of the structure of the capacitor shown in FIG.
In FIG. 8, the metal thin film electrode 13 and the margin portion 14a
The vapor-deposited film 14 having the above and the vapor-deposited film 16 having the metal thin film electrode 15 and the margin portion 16a are laminated so that the margin portions 14a and 16a are in opposite directions to provide the metallikon layers 17 and 18.

FIGS. 9 (a) and 9 (b) are schematic views from the directions A and B in FIG. In FIG. 9 (a),
Metal thin film electrodes 13 and 15 on polymer films 14 and 16
Has a thin film formed on both ends in the width direction. On the other hand, FIG.
In (b), the metal thin film electrodes 13 and 15 do not have the metal thin film electrodes formed at one end with margin portions 14a and 16a. The metal thin film electrodes 13 and 14 are provided with metallikon layers 17 and 18 after the left and right margin portions 14a and 16a are laminated alternately.

[0010]

However, in the conventionally proposed winding type film capacitors, the film withstand voltage cannot be increased due to the distortion at the beginning of the vapor deposition film and the distortion of the film due to winding. Has to be designed to be low, and because of this, the film thickness has become thick and miniaturization cannot be promoted.

In addition, the laminated type film capacitor has a structure in which distortion of the film is extremely small, so that the withstand voltage of the film can be designed to be high, which is advantageous for downsizing, but an electrode having a metallikon on four sides other than the laminating direction. Since the vapor deposition electrodes are arranged with the film sandwiched between the two surfaces other than the extraction surface, this portion has a relatively low withstand voltage, and since discharge between electrodes occurs at a low voltage, further high withstand voltage and further miniaturization are promoted. There was a problem that I could not do it.

The present invention solves the above-mentioned conventional problems, and an object of the present invention is to provide a film capacitor capable of high withstand voltage and miniaturization.

[0013]

In order to achieve this object, the film capacitor of the present invention forms a horizontal margin in the width direction in addition to a normal vertical margin in the longitudinal direction on a thin film electrode of a vapor-deposited film and makes contact with a metallikon. A margin portion is formed on two sides of a vapor-deposited film that constitutes two opposite end surfaces other than the surfaces.

[0014]

With the above structure, the obtained laminated type film capacitor has margin portions formed at both ends of the laminated thin film electrodes other than the metallikon contact end. Since the voltage becomes high and a stable capacitor can be obtained, and the potential gradient with respect to the thickness of the film used for the dielectric can be designed to be high, the film thickness can be made thin and the film capacitor can be miniaturized.

[0015]

EXAMPLES The detailed contents of the present invention will be described below with reference to examples.

1, 3 and 4 show an embodiment of the present invention. FIG. 1 shows a vapor deposition film having metal thin film electrodes having vertical and horizontal margins used in the present invention. Length (D direction) 5000m, Width (C direction) 250m
m, 9 μm thick polyethylene terephthalate (hereinafter P
An aluminum thin film 20 portion is formed as a metal thin film electrode on the ET) film 19 by vacuum deposition. The space between the aluminum thin films 20 is divided by a vertical margin (electrode surface margin) 21 having a width of 3 mm in the longitudinal D direction (electrode surface direction) and a lateral margin (end surface margin) 22 having a width of 2 mm in the width C direction (cutting surface direction). Has been.

The vertical and horizontal margins 21 and 22 are formed by masking with tape and oil during vapor deposition, or by laser beam or burn-off after vapor deposition.
The aluminum thin film 20 portion, the vertical margin 21 portion, and the horizontal margin 22 portion are cut by using the vapor deposition film with the margin thus produced, so that the aluminum thin film 20 portion having a predetermined shape and the vertical and horizontal margins are provided. The vapor-deposited film that constitutes the multilayer capacitor is obtained.

The vapor-deposited film cutting point for obtaining the vapor-deposited film forming the above-mentioned laminated capacitor is shown in FIG. 5 where the center G, G'of the vertical margin 21 and the center I of the distance L between the vertical margins G, G'are cut. To do. At this time G-
The distance between G'is L, and the distance between GI and G'-I is L / 2. Next, the centers H and H'of the lateral margin 22 are cut. The distance between H-H 'is W. By cutting in this way, vapor-deposited films of E and F are obtained.

FIG. 2A shows a vapor deposition film E, and FIG. 2B shows a vapor deposition film F. The three sides of the aluminum thin film 20 portion of the vapor deposition film E have a vertical margin 21 and a horizontal margin 2
2 is present, 25 is a cut surface of the vertical margin 21, 23 is a cut surface of the horizontal margin 22, and 24 is the aluminum thin film 20.
It is a cut surface of a part. Further, there are vertical margins 21 and horizontal margins 22 on three sides of the aluminum thin film 20 portion of the vapor deposition film F, 27 is a cut surface of the vertical margin 21, 23 is a cut surface of the horizontal margin 22 portion, and 26 is the aluminum thin film 2.
It is a cut surface of the 0 part.

In order to obtain a laminated capacitor element, the vapor-deposited films E and F obtained as described above are alternately cut surfaces 25 and 26, cut surfaces 24 and 27, and cut surfaces 23 are joined together. The layers are stacked so that the capacitance of the capacitor to be obtained is obtained.

FIG. 3 shows an external view of the multilayer capacitor of the present invention without an outer casing. Hexahedral upper surface 28 in the stacking direction
The lower surface 29 is a film on which the vapor deposition electrode is not formed, and the protective layer 30 is formed on the lower surface 29. In addition, one of the other four surfaces is a metallikon 3 as an electrode for drawing out an external electrode.
1 is formed. The other pair of facing surfaces is a cut surface 33, and an end surface margin (lateral margin 22) of the present invention for improving the withstand voltage of the cut surface is provided on the cut surface 33. FIG. 4 shows a device configuration diagram of FIG.

FIG. 5A (cross-sectional schematic view of FIG. 4 viewed from the J direction) and (b) (cross-sectional schematic view of FIG. 4 viewed from the K direction) are schematic structural views of the multilayer capacitor of the present invention. .

In FIGS. 4, 5 (a) and 5 (b),
On one side of the 9 μm-thick PET film 19, the end face margins 35 and 36 having a width of 1.0 mm and the width 1.
An electrode surface margin 37 of 5 mm was formed. On the other hand, an aluminum thin film 3 formed by a vacuum deposition method on one surface of a PET film 19 having a thickness of 9 μm and having the same outer dimensions as a pair.
On the three sides of 9, the end face margin 40 of the cut surface with a width of 1.0 mm,
41 and an electrode surface margin 42 having a width of 1.5 mm were formed.
As shown in FIG. 5A, these two kinds of vapor-deposited films were laminated on each other so that the end face margins 35 and 40, 36 and 41 of the cut surface overlap. The number of laminated layers was changed according to the capacity of the capacitor. The external extraction electrodes are shown in FIGS.
As shown in (b), the electrode 38 was formed for the aluminum thin film 34, and the electrode 43 was formed for the aluminum thin film 39 by metallikon. After the lead wire 32 was attached to the capacitor element thus formed, the capacitor element was put in a plastic case, and the space between the case and the capacitor element was filled with resin to make an exterior.

In the description of the embodiments of the present invention, the polymer film forming the vapor-deposited electrode was a PET film. However, in addition to the PET film, a polymer film such as polypropylene, polyethylene naphthalate or polyphenylene sulfide should be used. You can Further, zinc can be used as the vapor-deposited metal in addition to aluminum, and the shape, thickness and dimensions are not limited to those in the above embodiment.

[0025]

With this structure, the withstand voltage of the capacitor is improved. Table 1 shows the withstand voltage with and without the end face margin.

[0026]

[Table 1]

As shown in (Table 1), by providing the end face margin of the present invention, the withstand voltage was greatly improved as compared with the case where there was no end face margin.

9 μm when the end face margin width is 0.2 mm
600V to 2 by using thick PET film
It increased to 000V. When the end face margin was 1.0 mm, a withstand voltage of 3000 V was obtained. This improvement in withstand voltage is not limited to PET having a thickness of 9 μm, and the same withstand voltage improvement effect was obtained with any film thickness and with films other than PET. As a result, the withstand voltage targeted by the present invention can be obtained when the width of the end face margin is approximately 0.2 mm or more.

As described above, the withstand voltage is close to the withstand voltage of the film itself, and by making full use of the film characteristics as an insulator, 1. It has the same capacity and voltage as compared with the wound type. When trying to obtain a film capacitor, the potential gradient of the polymer film can be increased, so that the film thickness is reduced to 30-50.
% Can also reduce volume.

2. In comparison with a multilayer capacitor, it is possible to provide a capacitor having a withstand voltage several times higher than that of a capacitor having the same capacity and volume.

3. Since the capacitor has a high withstand voltage, high safety can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a vapor deposition film having a margin in a longitudinal (longitudinal) direction and a lateral (width) direction of a film used for a film capacitor in one embodiment of the present invention.

2A is an explanatory diagram of an E portion of FIG. 1; FIG. 2B is an explanatory diagram of an F portion of FIG.

FIG. 3 is an external view of a laminated type film capacitor of the present invention.

FIG. 4 is a configuration diagram of an element in which an end surface margin is provided on a cut surface of the present invention.

5 (a) Schematic view of the cross section viewed from the J direction in FIG. 4 (b) Schematic view of the cross section viewed from the K direction in FIG.

FIG. 6A is an external configuration diagram of a conventional winding type film capacitor element. FIG. 6B is an element configuration diagram of a conventional winding type film capacitor.

FIG. 7 is an external view of a conventional laminated type film capacitor.

FIG. 8 is a schematic configuration diagram of a conventional laminated type film capacitor element.

9A is a schematic view of a cross section viewed from the direction A of FIG. 8B is a schematic view of a cross section viewed from the direction B of FIG.

[Explanation of symbols]

19 Film 20, 34, 39 Aluminum thin film 21, 37, 42 Vertical margin (electrode surface margin) 22, 35, 36, 40, 41 Horizontal margin (end surface margin) 23, 24, 25, 26, 27, 33 Cut surface 28 Upper surface 29 Lower surface 30 Protective layer 31 Metallicon 32 Lead wire 38, 43 Electrode

Front page continuation (72) Inventor Kiyuki Sugiura 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A hexahedral film capacitor comprising a stack of metallized films obtained by vapor-depositing a metal thin film on a polymer film as a dielectric, wherein the capacitor has no metal vapor-deposited thin film on the upper and lower surfaces in the stacking direction. Of the four side edges of the metallized film having a molecular film disposed thereon and forming the other four sides by lamination, one side has a metal vapor deposition thin film to serve as an external extraction electrode portion, and the other three sides. Is a margin portion without a metal vapor-deposited thin film, and the metallized film is laminated such that the external extraction electrode portions are opposite to the metallized film in the laminating direction. 2. The polymer film is polypropylene,
The film capacitor according to claim 1, which is polyethylene terephthalate, polyethylene naphthalate or polyphenylene sulfide. 3. The film capacitor according to claim 1, wherein a margin width of the end face where the metal thin film is not formed up to the end is 0.2 mm or more.