JPH02192709A - Manufacture of laminated film capacitor - Google Patents

Abstract

PURPOSE:To manufacture a high quality capacitor by removing shortcircuited parts of sectional surfaces making insulation gap between the sectional surfaces by a method wherein the metallic layers on two laminated sectional surfaces formed on unit capacitors by cutting off and dividing processes are etched away. CONSTITUTION:Metallized plastic films 3 comprising high molecular films 1 on whose one side aluminum thin films 2 are evaporated are laminated while zinc layers 4 are provided on both sides of the plastic films 3 so as to form a base capacitor 5. This base capacitor 5 is cut off by a rotary saw 7 to be divided into unit capacitors 6. Then, the metallic layers on the sectional surface 8 can be removed by etching away the laminated sectional surface 8 of the capacitors 6. Through these procedures, the sufficient insulation gap can be left between the metallic layers in opposite polarities in the sectional surface while removing the shortcircuited parts on the sectional surface to assure high quality of the capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method of manufacturing a multilayer film capacitor that is widely used in electrical and electronic equipment.

BACKGROUND OF THE INVENTION Conventionally, this type of laminated film capacitor consists of a metalized plastic film 3 in which a thin film 2 of a metal such as aluminum or zinc is deposited on a polymer film 1 such as polyethylene terephthalate or polycarbonate, as shown in FIG.
are stacked, and a zinc layer 4 is formed on both opposing sides by lick thermal spraying for electrode extraction to form a base capacitor 5,
A method has been adopted in which unit capacitors 6 are obtained by cutting and dividing unit capacitors 6 from this base capacitor 5 using a cutting blade 7 such as a rotary saw blade.

The unit capacitor 6 of the multilayer film capacitor produced by such cutting and division has two laminated cut surfaces 8 produced by the cutting and division.

At this laminated cut surface 8, metal layers of opposite polarity adhere or face each other in close proximity, i.e. at a distance not exceeding the thickness of the dielectric layer (polymer film 1), for example 2 to 5 μm. are doing.

When a voltage is applied to such a unit capacitor 6, the insulation resistance decreases due to short circuit or creeping discharge.

Therefore, conventionally, as shown in FIG. 5, a high voltage higher than the voltage at which this unit capacitor 6 is used is applied between the electrodes 1o and io which are in contact with the zinc layers 4 on both sides by a high frequency power source 9. , a method has been adopted in which the metal layer at the laminated cut surface 8 is burned away.

Problems to be Solved by the Invention In such a conventional method, if there is a short-circuited part on the cut surface 8 of the laminated layer, the insulation cannot be restored, and even if a high voltage is applied, the part that was not causing the problem is short-circuited. There is a problem that burnout may cause a decrease in insulation resistance and an increase in dielectric voltage contact.

The present invention solves these problems, and aims to manufacture a multilayer film capacitor that improves the insulation properties and other quality of the multilayer film capacitor, improves manufacturing yield, and allows manufacturing of inexpensive products. The purpose is to provide a method.

Means for Solving the Problems In order to solve the above-mentioned problems, the method for manufacturing a multilayer film capacitor of the present invention involves removing the metal layer on the cut surface of the multilayer film produced in the unit capacitor by cutting and dividing, by etching treatment using plasma. It is characterized by doing.

Effect In the above configuration, by applying etching treatment between both laminated cut surfaces of the unit capacitor, it is possible to remove or crush the metal layer from the surface of the laminated cut surface to several μm inside. A sufficient insulation distance can be maintained between metal layers of opposite polarity in
In addition, it is possible to remove short circuits on the laminated cut surface, and since no voltage is applied between the electrodes of the unit capacitor, there is no risk of burning out anything other than the metal layer on the laminated cut surface, resulting in a decrease in insulation resistance and an increase in dielectric construction time. It never brings.

Example Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of an apparatus used in a method for manufacturing a multilayer film capacitor according to an embodiment of the present invention. The unit capacitor processed by the apparatus shown in FIG. 1 is similar to that shown in FIG. 2 above. That is, the unit capacitor 6 uses a polyethylene terephthalate film with a thickness of 5 μm as the polymer film 1, and a plurality of metallized plastic films 3 with a thin aluminum film 2 deposited on one side of the polymer film 1 (in FIG. 4 layers) are laminated and zinc layers 4, 4 are formed on opposite sides to draw out the electrodes to form a base capacitor 5, and this base capacitor 5 is turned into a unit capacitor 6 having a predetermined capacity by a rotating saw blade 7. It is cut and divided. 6a is called the opposing width.

As shown in FIG. 1, the unit capacitor 6 is constructed on the lower side of a pair of parallel flat plate molds 12 and 12 which are arranged vertically at a predetermined interval inside an etching processing apparatus 11 maintained in a vacuum state. , one of the laminated cut surfaces 8.8 is placed in contact with the parallel plate electrode 12.12, and a high frequency power source 13 is applied to the parallel plate electrode 12.12.
．． A high frequency voltage of 56 M) tz was applied, chlorine gas 14 was introduced at l Torr, and the current density I W/
Etching was performed for 1 hour using cffl. As a result, the oxide film covering the surface of the thin film 2 of vapor-deposited metal (aluminum) is removed by the ion collision of the plasma generated between the electrodes, and then the aluminum undergoes a chemical reaction with the chlorine atoms in the plasma and is removed. . Note that an arrow 15 indicates exhaust. In this embodiment, since one laminated cut surface 8 of the unit capacitor 6 was placed closely on the parallel flat plate AI 12, the other laminated cut surface 8 was also subjected to the cut surface treatment alternately.

FIG. 3 shows the change in insulation resistance distribution of the unit capacitor of the multilayer film capacitor before and after plasma etching treatment in the above embodiment.

In other words, the distribution of insulation resistance of the unit capacitor before processing immediately after cutting and dividing is 10% from that in the short circuit state.
It has a wide distribution up to 5 MΩ. When a group of unit capacitors having such an insulation resistance distribution were subjected to the etching treatment according to the embodiment, the insulation resistance of all unit capacitors became 10' MΩ or more.

Figures 4 (a), (b), and (c) compare the electrical characteristics of a unit capacitor when a voltage application process using a conventional method and an etching process according to the above example were performed on a multilayer film capacitor. (a) is the withstand voltage, (b) is the insulation resistance, and (C) is the dielectric loss tangent. As a result, a unit capacitor having excellent electrical properties can be obtained, and in particular, the withstand voltage is significantly improved.

Effects of the Invention As described above, according to the method for manufacturing a multilayer film capacitor of the present invention, electrical properties such as insulation resistance, etc.
Multilayer film capacitor products of extremely high quality can be obtained, and the yield of electrical characteristics during manufacturing is also significantly improved, making it possible to provide high quality and inexpensive products to the market.

[Brief explanation of the drawing]

FIG. 1 is a schematic sectional view of an apparatus used in a method for manufacturing a multilayer film capacitor according to an embodiment of the present invention, FIG. 2 is a perspective view showing the cutting process of a unit capacitor of a multilayer film capacitor, and FIG. Figures 4 fa), (b), and fc) showing the electrical characteristics of the multilayer film capacitor before and after the processing of the above embodiment of the present invention are the multilayer films obtained in the above embodiment and the conventional example. FIG. 5, which is a diagram showing the electrical characteristics of a capacitor, is a schematic perspective view showing a conventional method. 3... Metallized plastic film, 5... Base capacitor, 6... Unit capacitor, 8... Laminated cut surface, 11... Etching processing device. Agent Yoshihiro Morimoto Figure 7 Figure 5 Figure 5 - Mother] Type 2! ? − Kamo Toichi is here.

Claims (1)

[Claims] 1. A multilayer structure characterized in that metallized plastic films are stacked to form a base capacitor, the base capacitor is cut and divided into unit capacitors, and each of the two laminated cut surfaces formed on the unit capacitor is subjected to an etching process using plasma. Method of manufacturing type film capacitor.