JPS6129533B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved method of manufacturing a multilayer film capacitor. Conventionally, a multilayer film capacitor mainly consists of a dielectric material 1 such as a polyester film and a metal such as aluminum deposited on it to form an internal electrode 3, and then this is laminated to form a metallized long-band dielectric material. An external terminal electrode 4 is formed on both end faces of the laminated part by metal spraying and cut into a predetermined width using a cutting machine, and an electrode margin 2 is provided on both sides of the internal electrode 3. As shown in FIG. 2, there is also a structure that does not have electrode margins 2 on both sides of internal electrodes 3. However, the former has electrode margins 2 on both side surfaces, which limits the capacitance that can be obtained per unit volume, and also has the drawback that the capacitance varies due to mask displacement and scattering during metal spraying of the internal electrodes. In the latter case, the dielectric layer is thin, and when cutting both side surfaces, the internal electrode partially wraps around the side dielectric, resulting in a short circuit or edge discharge between the opposing electrodes on both sides, which causes the capacitor to function as a capacitor. The problem was that it was unreliable. The present invention improves the above-mentioned drawbacks and provides a method for manufacturing a multilayer film capacitor that has a large acquired capacitance per unit volume, small variations in capacitance, and is highly reliable. That is, after alternately stacking and fusing organic films with internal electrodes provided on the entire surface except for one end located on the opposing electrode side, external terminals are attached to the exposed portions of the opposing internal electrodes of the stack. In a laminated element provided with electrodes, the entire surface of the laminated element is covered with wax, resin, etc. that can be dissolved and removed with an organic solvent, and then the laminated element is cut into multiple pieces at right angles to the external terminal electrodes, and the exposed both sides are cut. A part of the internal electrode is chemically dissolved and removed along the surface part to form an internal electrode margin on both side parts, and if necessary, the side part is coated with insulating resin to further improve reliability. It is characterized by being coated by heating or by heating. The present invention will be described below with reference to embodiments shown in FIGS. 3 to 7. As shown in FIG. 5, an internal electrode 6 is formed by vapor-depositing aluminum metal on the entire surface of one side of the long dielectric material 5 made of polyester film except for one end, and the electrodes are laminated and bonded together by heat pressing. become
Thereafter, external terminal electrodes 7 are formed on both end faces of the laminated portion by metal spraying. Thereafter, as shown in FIG.
Then, the laminate was cut into multiple pieces in the a-a' direction perpendicular to the external terminal electrode 7, and immersed in the dilute acid solution shown in the table for 5 minutes, 10 minutes, 20 minutes, and 40 minutes, respectively. , then wash thoroughly with water, and finally apply adhesive 8.
was removed by washing with an organic solvent such as trichlorethylene to obtain a multilayer film capacitor as shown in FIG. Further, in order to improve the reliability of the capacitor, a resin was applied to both side surfaces 10 of the multilayer film capacitor shown in FIG. 3 to cover both sides, thereby obtaining the multilayer film capacitor shown in FIG. 4. In FIG. 4, numeral 10 indicates a resin as a covering material. Also, instead of applying resin, both side surfaces may be sealed by thermocompression bonding. The internal electrode is melted from the side of the multilayer capacitor element, and the internal electrode margin formed thereby varies depending on the concentration of the solution, temperature, and immersion time.The results are as shown in Figure 8. The degree of electrode margin can be set by time or solution concentration.

[Table] Also, in the above example, the internal electrodes were thermally sprayed with aluminum, but metals other than aluminum or laminated using foil have similar effects, and dilute acid solution A similar effect can be obtained with nitric acid, sulfuric acid, phosphoric acid, or iron chloride solution. By the method of the present invention described above, mass production is easy and production efficiency can be improved. The side electrode margin is reduced, and the acquired capacitance per unit volume is large.
A small, large-capacity capacitor can be obtained. Capacity variations due to internal electrode mask misalignment, bleeding, etc. are reduced. Capacitance can be adjusted, improving capacitance yield during manufacturing. It has many effects such as the ability to obtain a highly reliable multilayer film capacitor, and is useful industrially and practically.

[Brief explanation of the drawing]

1 and 2 are respectively cutaway perspective views of essential parts of a conventional multilayer film capacitor, FIG. 3 is an embodiment of the multilayer film capacitor of the present invention, and FIG. 4 is a cross-sectional view of the multilayer film capacitor of the present invention. In other embodiments, A is a cutaway perspective view of essential parts of a multilayer film capacitor, B is a sectional view taken along b-c of A, and FIGS. FIG. 8, a perspective view illustrating an example of the manufacturing process, is a correlation diagram between the type of dilute acid solution, concentration, immersion time, and internal electrode dissolution depth. 2, 11: internal electrode margin, 3, 6: internal electrode, 4, 7: external terminal electrode, 5: long strip dielectric,
8: Adhesive agent, 9: Side part, 10: Resin.

Claims (1)

[Claims] 1. After alternately laminating and fusing organic films in which internal electrodes are provided on the entire surface of the organic film except for one end located on the opposing electrode side, the opposing internal electrodes of the laminate are exposed. In a laminated element in which an external terminal electrode is provided on a portion, the entire surface of the laminated element is covered with wax, resin, etc. that can be dissolved and removed with an organic solvent, and then the laminated element is cut into a plurality of pieces, and the exposed side surfaces are covered with wax, resin, etc. 1. A method of manufacturing a multilayer film capacitor, comprising: chemically dissolving and removing a portion of the internal electrode along the line, and forming internal electrode margins on both side surfaces. 2. The method of manufacturing a multilayer film capacitor according to claim 1, wherein both side surfaces on which the internal electrode margins are formed are coated with an insulating resin. 3. The method of manufacturing a multilayer film capacitor according to claim 1, wherein both side surfaces on which the internal electrode margins are formed are coated with heat.