JPS61119024A - Laminated 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 electronic equipment, electrical equipment, etc.

Conventional configurations and their problems In recent years, the use of electronic components as chips has been remarkable due to advances in packaging technology. In addition, chip components are often used for mounting consumer devices and industrial devices due to their advantages such as high mounting productivity and high mounting density, which allows devices to be made smaller.

There is a strong demand for film capacitors, which are one of the electronic components, to be made into chips for the reasons mentioned above, but the dielectric materials originally used in film capacitors are organic films such as polyethylene terate film, polypropylene film,
These are polycarbonate fill films and polystyrene films, which have lower heat resistance than other parts and are not used for mounting chip parts.Soldering methods such as soldering dip and reflow soldering are used for printed circuit boards. If the dielectric film shrinks or melts due to heat when mounting the capacitor, or if there is moisture inside the capacitor element.

There was also the inconvenience that the rapid heating during mounting caused the moisture to expand rapidly, causing the element to swell and the exterior to crack.

These factors delayed the development of film capacitors into chips.

A conventional multilayer capacitor will be explained below with reference to FIG. FIG. 2 shows a cross-sectional view of a conventional multilayer capacitor. Electrodes (2) are provided by vacuum-depositing aluminum on both sides of a polyethylene terephthalate film (1) used as a dielectric, and a single layer of lacquer (3) made of solvent-coated polycarbonate resin is provided on this L, and these processes are performed. is used as an element film (A), and 100 layers of this element film (A) are laminated. Further, a layer (3) of lacquer coated with polycarbonate resin in a solvent is provided on both sides of the polyethylene terephthalate film (1) as described above, and this is used as a protective film CB), and this protective film (B) is laminated as shown in Figure 2. Several tens of layers are provided below F of the film (A). A metallicon layer (4) sprayed with zinc is provided on both end faces of the thus laminated films (A) and (B), and a lead wire (5) is further attached to the metallicon layer (4).
4) and epoxy resin outside Fj (6
) will be established.

50 multilayer capacitors configured in this way were heated to 210°C.
When dipped for 10 seconds in a solder dip bath,
The average value of the capacitance change was 120%, and when 10 of them were disassembled, the protective film (B) and the element film (A) were shrunk and peeled off from the metallicon. As described above, the above structure and materials have problems such as a change in capacitance due to thermal shrinkage of the element film (A) or an increase in dielectric loss tangent due to poor contact with the metallicon layer.

Purpose of the Invention In view of the above-mentioned problems, the present invention provides a capacitor that reduces the thermal shrinkage of the element film when the capacitor element is exposed to high temperatures, reduces capacitance change, and ensures reliable contact between the metallcon and the electrode. It is something to do.

Structure of the Invention In order to achieve the above object, it is thought that the best method is to use a dielectric film and coating dielectric that can withstand the heat during mounting. There are few suitable materials. In addition, even if the capacitor is made of materials that can withstand heat, problems such as swelling of the element will occur if the capacitor is constructed as described above. In order to reduce heat shrinkage of the element film and protective film or bulge of the element, a holder is provided on both sides or in the center of the element configured as in the conventional example, which is carved by the heat during mounting and does not shrink due to heat. When the element film or the protective film shrinks due to heat during mounting such as solder dip or flow soldering, and attempts to shrink in the direction perpendicular to the thickness of the element film, the holder The present invention attempts to control this and suppress the thermal shrinkage of the element film or protective film, thereby eliminating the inconveniences seen in the conventional examples.

DESCRIPTION OF THE EMBODIMENTS An embodiment of the present invention will be described below with reference to FIG. FIG. 1 shows a cross section of a multilayer capacitor in one embodiment of the present invention. 100 pieces of element film (A) similar to the conventional example
The holding body (C) of the present invention, in which both surfaces of a polyimide film (7) are coated with an epoxy resin (8), is placed on top and bottom of the laminated layer in 1ONvX layer.

Furthermore, 30 layers of protective films (B) similar to those shown in the conventional example are provided above and below. A metallicon layer (4) sprayed with zinc is provided on both end faces of the laminated structure, a lead wire (5) is further welded to the metallicon layer, and an epoxy resin sheath (6) is provided on the outside of these layers.

When 50 multilayer capacitors configured in this way were dipped in a solder dipping bath at 210°C for 10 seconds, the average capacitance change was 12%, and the dielectric loss tangent also remained unchanged, ensuring reliable contact between the metallcon and the opposing @pole. It turned out to be.

Note that if the heat-resistant holder is not insulating, both metallization contacts will be electrically connected, resulting in a short circuit. Therefore, holding pair (C)
must be insulating 4-1. In addition, it is better to use a film-like holder (C) for capacitor processing, but the film-like holder (C) does not have the mechanical strength to regulate the spacing between metallic condensates, although it depends on the thickness6.On the other hand, the film thickness By increasing the thickness of the holder (C), the mechanical strength increases and the effectiveness of the holder (C) increases.However, as the thickness of the holder (C) increases, the volumetric proportion of the holder (C) in the element decreases. becomes larger, and the element shape becomes larger. Therefore, in the present invention, the mechanical strength of the holder ((1) is increased by coating an insulating film with an adhesive as a holder, laminating it in the same way as the element film, and then bonding the adhesive with heat. If such a method is adopted, the holder also has the effect of acting as a protective film.Although it is possible to use the holder and the protective film together in this way, this is not the only option.

Furthermore, the holder needs to have high heat resistance so that it does not shrink due to heat during mounting by firmly holding the element as described above, and maintains the spacing between the metal contacts. Therefore, thermoplastic films and adhesives have low heat resistance and cannot achieve the purpose. The effect of the holder can be obtained by using a thermosetting insulating film and adhesive as in the examples. Furthermore, for example, if either the insulating film or the adhesive is not heat resistant, the effect will be low. In the examples, a polyimide film is used as the insulating film, and an epoxy resin is used as the adhesive, but the invention is not limited to this.

As described above, according to this embodiment, by providing the heat-resistant holder in the element, when the capacitor is heated, the thermal shrinkage of the element film or the protective film is reduced,
It is possible to suppress changes in capacitor characteristics such as reducing capacitance changes, and improve solder heat resistance of the capacitor.

Further, in this embodiment, the holders are provided on both sides of the element film, that is, on a part of the protective film, but the same effect can be obtained even if the holders are provided on any part of the element, and the holders are not limited to being provided on both sides. Furthermore, it has the effect of suppressing swelling of the element due to rapid heating during mounting when the element contains moisture.

Effects of the Invention According to the present invention. By providing a holder in a part of the thickness direction of the element film of the capacitor, the holder regulates the spacing of the metallization and reduces the heat shrinkage of the protective film and element film that tend to shrink due to heat during mounting. Characteristic changes, especially capacitance changes, tan δ
Reduces changes in

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a multilayer capacitor according to the present invention, and FIG. 2 is a sectional view of a conventional multilayer capacitor. (1)... Polyethylene terephthalate film (dielectric), (2)... Electrode, (3)... Single layer of lacquer, (4)... Metallicon layer, (5)... Lead wire,
(6)...Epoxy resin exterior, (7)...Polyimide film, (8)...Epoxy resin, (A)...
Element film, (B)...protective film. (C)... Holder agent Yoshihiro Morimoto Figure 1

Claims (1)

[Scope of Claims] 1. A laminated capacitor in which a holder is provided in a part of the capacitor in the film thickness direction in which metallized plastic films are laminated to maintain the element shape during heating. 2. The multilayer capacitor according to claim 1, wherein the holder is made of two different materials, at least one of which is a flexible material. 3. The multilayer capacitor according to claim 2, wherein the two different materials of the holder are an insulating film and an adhesive. 4. The multilayer capacitor according to claim 3, wherein the insulating film and adhesive are thermosetting resins.