JPS62136012A - Film capacitor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a film capacitor used in equipment in general consumer and industrial fields.

Conventional technology In recent years, equipment has become smaller and smaller in both consumer and industrial applications.
On the other hand, there is a growing trend toward diversification of devices to meet various needs, and at the same time, electronic components such as film capacitors used in these devices are desired to become smaller.
There is a growing demand for products that can withstand various harsh conditions.

Conventional film capacitors simply consist of alternating planar dielectric sheets and metal electrodes, which are then wound to form a capacitor.0 Below, we will explain the conventional film capacitor as described above with reference to the drawings. 0 Figures 3 and 4 show cross sections of conventional film capacitors. Figure 3 shows a foil-type capacitor that uses metal foil for the metal electrode, and Figure 4 shows a capacitor that uses metal foil as a metal electrode on the surface of a dielectric sheet. FIG. 2 is a cross-sectional view of a metallized film capacitor on which a deposited electrode film is formed. In FIG. 3, 1 is a dielectric sheet;
2 is a metal foil, and 3 is a non-metallic part. In FIG. 4, 1 is a dielectric sheet, 2' is a deposited electrode film formed on the surface of the dielectric sheet 1, 3 is a nonmetallic part, and 4 is an electrode lead-out part.

The charge of the capacitor is transferred to a pair of metal foils 2-! which are opposed to each other with a dielectric sheet 1 in between! or on the metal electrodes of the deposited electrode film 21, at which time the pair of metal electrodes are mutually connected to the dielectric sheet 1.
and is insulated by the non-metallic part 3. The metal electrodes of the metal foil 2 and the deposited electrode film 21 are directly drawn out in the case of FIG. 3, and are drawn out outside through the electrode lead-out portion 4 in the case of FIG.

Problems to be Solved by the Invention However, in the above configuration, when an excessive voltage that far exceeds the capacitor's rating is instantaneously applied, instantaneous discharge occurs along the non-metallic part 3, and during discharge, The generated energy causes the insulation of the dielectric sheet 1 to deteriorate,
This has the problem of eventually leading to destruction of the capacitor. In response, there has been a desire to develop a capacitor with excellent withstand voltage against instantaneous excessive voltage.

In view of the above-mentioned problems, the present invention provides a film capacitor with improved withstand voltage against instantaneous excessive voltage by preventing discharge along the non-metallic portion.

Means for Solving the Problems In order to achieve this object, the film capacitor of the present invention has metal electrodes and dielectric notes whose ends extend to cover the end faces of the metal electrodes, which are arranged alternately. By extending the end of the dielectric trunk to cover the end face of the metal electrode, it is possible to prevent the discharge that would conventionally occur along the non-metallic part when an instantaneous excessive voltage is applied. become.

EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view of a base type film capacitor in a first embodiment of the present invention. In FIG. 1, 6 is a dielectric sheet, 6 is a metal electrode made of metal foil, and 7 is a non-metallic part. The dielectric sheet 5 extends to cover the end face of the metal electrode 6 and to be located below the metal electrode 6. The dielectric sheet used here is one-half the thickness of the dielectric sheet used in the conventional film capacitor shown in FIG. The arrangement of the non-metallic part 7 is based on the rated voltage of the capacitor,
It can be arbitrarily set in a range from 0 to the same range as the conventional one, depending on the target withstand voltage.

The operation of the film capacitor configured as above will be explained below.

When a normal voltage below the rated voltage is applied to the capacitor, charges are accumulated on the metal electrodes via one dielectric sheet 6 and another dielectric sheet extending from above. has been done. Even if an excessive voltage is momentarily applied due to the influence of external noise, in addition to the conventional insulation between the opposing metal electrodes 6 in the non-metallic part 7, the end faces of the metal electrodes 6 are covered with the dielectric sheet 6. Therefore, the dielectric strength is improved by the thickness of the dielectric sheet 5.

As described above, according to this embodiment, by covering the end face of the metal electrode 6, the withstand voltage against instantaneous excessive voltage is improved.

Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 is a cross-sectional view of a metallized film capacitor in a second embodiment of the present invention. In the same figure, 5
61 is a dielectric sheet, 61 is a metal electrode made of a deposited electrode film,
Reference numeral 7 denotes a non-metallic portion, which has the same structure as that shown in FIG. In the case of FIG. 2, since it is a metallized film capacitor, the electrodes are drawn out to the outside via the electrode lead-out portion 8.

In this embodiment, in order to ensure a contact area between the metal electrode 6' and the electrode lead-out part 8, the metal electrode 61 is continuously connected to the surface of the portion of the dielectric sheet 5 that covers the end surface of the other metal electrode. It is set up in

The withstand voltage of the metallized 7-ilm capacitor constructed as described above against instantaneous excess voltage is improved to the same extent as that of the embodiment shown in FIG. In addition, by extending the metal electrode 6t to the folded portion of the dielectric sheet 5, the contact area between the metal electrode 61 and the electrode lead-out portion 8 is increased, which improves resistance to electric shock. There is. “Effects of the Invention As described above, the present invention provides protection against instantaneous excessive voltage by arranging the end of the dielectric sheet to cover the end face of the metal electrode and to be located below the metal electrode. It can significantly improve pressure resistance, and its practical effects are significant.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of a foil-type film capacitor according to a first embodiment of the present invention, FIG. 2 is a cross-sectional view of a metallized film capacitor according to a second embodiment of the present invention, and FIG. Cross-sectional view of a type of film capacitor, No. 4
The figure is a cross-sectional view of a conventional metallized film capacitor. 6... Dielectric sheet, 6.6'... Metal electrode, 7... Non-metal part, 8... Electrode lead-out part. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (2)

[Claims] (1) Constructed by alternately arranging dielectric sheets made of an organic film and metal electrodes, so that the ends of the dielectric sheets cover the end surfaces of the metal electrodes and are located below the metal electrodes. A film capacitor characterized by being arranged in. (2) The metal electrode is composed of a deposited electrode film provided on the surface of the dielectric sheet, and this metal electrode is continuously provided on the surface of the portion of the dielectric sheet that covers the end surface of the other metal electrode. A film capacitor according to claim 1.