JPS6115576B2 - - Google Patents

Description

[Detailed description of the invention]

It is well known that in recent years, with the conversion of various electronic circuits to ICs and substrates, the modularization of each component has been rapidly progressing. For this reason, capacitors are also being required to be made smaller and more chipped, and various inventions and ideas have been made. The present invention relates to a compact, long-life, and highly reliable capacitor that meets these demands. Since capacitors such as general aluminum electrolytic capacitors use liquid or paste electrolytes or impregnating agents (hereinafter referred to as impregnating liquids), their airtightness is an important point in maintaining their characteristics. Currently, various methods of sealing capacitors that are commonly used include a method in which the sealing portion is sealed using an elastic sealing material such as rubber, and a method in which the capacitor is filled with resin or the like. However, these methods have problems during the manufacturing process, such as the adhesiveness being reduced due to leakage of the impregnating liquid during the resin curing, which impairs the sealing performance, and the problem that the sealing material such as rubber and the impregnating liquid or the resin Because the impregnating liquid comes into direct contact with the rubber and resin, during long-term reliability tests, the airtightness of the sealing part deteriorates due to the elution of corrosive substances from the rubber and resin and aging.
Problems arise when characteristics deteriorate after 3,000 to 5,000 hours. SUMMARY OF THE INVENTION The present invention aims to eliminate the above-mentioned drawbacks, provide a chip-type capacitor that can be made into a small external shape, and can be manufactured at low cost. Hereinafter, the present invention will be explained with reference to the embodiments shown in FIGS. A metal plate 1 made of aluminum or the like is coated with corrosive material such as polyethylene, polypropylene, polyamide (for example, nylon, a trade name of DuPont), polytetrafluoroethylene (for example, Teflon, a trade name of DuPont), etc., in order to avoid direct contact with the metal plate 1. The capacitor element is housed in a box-shaped case formed by drawing a plate laminated with a neutral plastic resin layer 2 so that the inner surface faces the resin layer side, and the edge of the case is connected to a drawer lead plate 5. It is welded together with the lid by high frequency heating or other thermocompression bonding to block leakage of the impregnating liquid. Figure 1 shows a case in which the above-mentioned metal plate that houses a capacitor element is laminated with resin, and the lid is flat and the case is drawn into a box shape. Figure 2 shows a case in which the lid and the case are formed at one end. Figure 3 shows a capacitor element that is integrally formed so as to be folded back, and the capacitor element is housed in a case as described above, and the edge of the case is welded and sealed together with the drawer lead plate 5 and the lid. is a perspective view, and b is a cross-sectional view. FIG. 4 shows a completed product in which terminals 6 are welded and connected to the lead plate 5 of the above-mentioned sealed capacitor element, and then molded with heat-resistant exterior resin 7. The chip capacitor of the present invention is constructed as described above, and compared to conventional products, it has a double-sealed structure, has a resin-molded exterior, and has excellent heat resistance, and its characteristics are extremely stable. A high degree of reliability can be obtained. Since the internal element structure can be freely selected such as a wound type or a laminated type, electrical characteristics such as impedance characteristics can be improved. The structure is made by drawing a laminated plate of the above-mentioned metal and non-corrosive plastic resin, and is then covered with resin, so any shape such as a rectangular parallelepiped or disk can be designed, and it can be made into modules such as ICs and printed circuit boards. can be easily realized. By processing the capacitor element into a laminated structure through the above-described free selection of the element structure, the space inside the case can be used more effectively and the capacitor element can be extremely miniaturized. The inside of the metal is laminated with a non-corrosive plastic resin layer such as polyethylene, polypropylene, nylon, or Teflon.
Impregnating liquid will not adhere and cause corrosion. Assembly is easy because the above-mentioned plastic resin layer is welded to seal the capacitor element.
Automation is easy and airtightness can be ensured. Since the outside of the capacitor case is made of metal such as aluminum, by drawing out the metal plate in contact with the metal part of the case, the capacitor can be electrically shielded from the outside and the heat dissipation effect can be further enhanced. Next, regarding electrolytic capacitors with a rating of 50WV and 1μF, a conventional product and a product of the present invention were manufactured, and the results of comparing the external dimensions and electrical characteristics are shown in the table, and the impedance frequency characteristics are shown in Figure 5. Figure 6 shows the life characteristics.

[Table] As a result, the product of the present invention is small and has a low impedance value at high frequencies.In the high temperature load life of 85℃, the conventional product failed the standard after 4000 hours and the test was discontinued, but the product of the present invention has a lifespan of 5000 hours. It can be seen that it is stable over time. As described above, the present invention can provide an extremely small and inexpensive chip capacitor with excellent electrical characteristics, and is of great industrial and practical value.

[Brief explanation of the drawing]

Figures 1 and 2 show examples of the chip-type capacitor case according to the present invention, where A is a perspective view, B is a cross-sectional view, and Figure 3 shows a capacitor element housed in the case of Figure 2. , A is a perspective view, B is a sectional view, FIG. 4 is a molded state of the capacitor shown in FIG. 3, A is a sectional view, B is a perspective view, FIG. 5 is a frequency-impedance characteristic diagram, and FIG. It is a high temperature load life characteristic diagram. 1: metal plate, 2: resin layer, 3: electrode foil, 4: electrolytic paper, 5: drawer lead plate, 6: terminal, 7: exterior resin.

Claims (1)

[Claims] 1. A capacitor element is placed in a case made by laminating a plastic resin layer 2 such as polyethylene, polypropylene, polyamide, polytetrafluoroethylene, etc. on a metal plate 1 such as aluminum and drawing the plate so that the inner surface is on the resin layer 2 side. A chip-type capacitor is housed, the edge of the case is welded and sealed via a lead plate 5, and then the chip-shaped capacitor is packaged with resin.