JPS62203315A - 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 capacitor using a dielectric film used in electronic equipment and electrical equipment.

2. Description of the Related Art In recent years, efforts have been made to make electronic and electrical equipment multi-functional and miniaturized, and the electronic components used therein are becoming lighter, thinner, shorter and smaller. A typical example is chip technology. Therefore, the surface mounting method, which is different from the conventional method for mounting components on printed circuit boards that constitute circuits, has rapidly progressed. In this method, all parts are fixed on one or both sides of the board with adhesive or cream solder, and soldered by passing them through a solder bath or high-temperature furnace. Therefore, the component body is directly exposed to high temperatures, and the temperature applied to the component body is much higher than that of a conventional lead-equipped component in which only the lead wires are immersed in a solder bath. For example, in the case of a T-film capacitor, the internal temperature of the capacitor when only the lead wires are soldered with conventional leads is 100 to 130.
℃, whereas the internal temperature of a chip film capacitor is 210 to 240℃, which is about 100℃ higher. In addition, in order to miniaturize the equipment, we use methods to reduce the space inside the equipment and increase the density of the board structure, so when using it, the heat generated by active electronic components (ICs, transistors, diodes, etc.) is reduced. If there is a cage inside the equipment, the temperature will rise.

As described above, chip components are being used in harsher conditions in terms of temperature than conventional leaded components.

Film capacitors have conventionally used films such as polyethylene terephthalate (hereinafter referred to as PET) and polyglopylene (hereinafter referred to as PP) as dielectric materials, but these had difficulties in terms of heat resistance, so a new plastic film with excellent heat resistance was used. The material has come to be desired.

Recently, polyphenylene sulfate (hereinafter referred to as PPS) has been developed as a heat-resistant dielectric film material, and PETS
It has superior heat resistance compared to PP, and also has superior electrical properties, which is one of the major characteristics of film capacitors.
In particular, it has come to be widely used in chip capacitors.

Hereinafter, the conventional capacitor as described above will be explained with reference to the drawings. Figure 4 shows metallized PPS,
FIG. 2 is a film configuration diagram of a y-ilm capacitor. Electrodes are provided by vacuum deposition on the surface of the PPRPP film on one side that forms the dielectric, and non-metalized PP is provided on the other dielectric.
S films are used, which are wound together or laminated, and hot press molded to ensure adhesion between film layers and to stabilize mechanical and electrical properties. In Figure 4,
1 indicates double-sided metallized PPS film, 2 indicates non-metallized PPS film
A PS film is shown. Further, 3 indicates an electrode, which is formed by vacuum deposition. Note that FIG. 4 shows an example in which the average surface roughness of both surfaces of the PPS film is extremely small.

The operation of the capacitor configured as above will be explained below. First, when a voltage is applied to both electrodes formed by vacuum evaporation via an external electrode such as an electrode plate or sprayed metal, charge is accumulated in the dielectric PPS film sandwiched between the electrodes, and the capacitor Play the role. At this time, the material of the electrodes formed by vacuum evaporation is generally aluminum metal, and the thickness is often set to around 400 mm. Aluminum metal C or below AI! )
It is inferior to other metals in terms of corrosion and electrolytic corrosion caused by water, and moreover, when the thickness is only around 400λ, it is necessary to devise ways to use it and form a film. As far as the film formation method is concerned, it may be possible to improve adhesion to the dielectric film and limit corrosion and electrolytic corrosion to only the electrode surface.

Problems to be Solved by the Invention However, like the PP film, the PPS film is a nonpolar material, and its adhesion to the Al electrode film is weak. In particular, when the average surface roughness of both surfaces of the PPS film in a capacitor having the above structure is made very small, corrosion and electrolytic corrosion due to the penetration of water rapidly progress. Due to the low average surface roughness, the AI! formed on the film! The electrode film is only formed on the surface of the film and has almost no mechanical strength. In the case of PP and PET, even if the average surface roughness is small in this way, the film can be partially melted by the high-temperature A11 particles during vacuum deposition, so mechanical strength can be ensured. However, PPS film is a heat-resistant material, and it is difficult to melt the film surface and ensure mechanical strength.

In view of the above problems, the present invention provides a capacitor with improved moisture resistance by increasing the adhesion strength of the A/electrode film.

Means for solving interlayer points To achieve this objective, the capacitor of the invention is made of PP
The average surface roughness of both surfaces of the S film is 0.04 μm or more.

For production The effect of this configuration will be explained below.

In other words, the average surface roughness of both surfaces of the PPS film is 0,
When an Al electrode film of less than 0.04 μm is used to form a capacitor by vacuum evaporation, a significant deterioration in moisture resistance is observed. This is because the mechanical strength of the film and the Al electrode film could not be obtained, and corrosion and electrolytic corrosion due to moisture entering from the outside progressed simultaneously from the interface with the film and from both sides of the electrode surface.

When the average surface roughness is 0.04 μm or more, the adhesion area with the A4 electrode film increases and the mechanical strength is significantly improved. Therefore, corrosion and electrolytic corrosion caused by moisture entering from the outside are limited to only the electrode surface, and the rate of corrosion can be stopped to less than 10%, thereby improving moisture resistance.

EXAMPLE An example of the present invention will be described below with reference to the drawings.

FIG. 1 shows a film configuration diagram of a capacitor in an embodiment of the present invention. Reference numeral 11 denotes a dielectric PPS film, which is constructed by forming stain electrodes on both surfaces of this PPS film 11 by vacuum deposition, and overlapping it with a non-metalized PPS film 12 on the other side. 13 indicates an electrode.

The operation of the capacitor configured as above will be explained below. When a voltage is applied to both electrodes 13 via an external electrode such as an electrode plate or sprayed metal, this electrode 13
pps, y ilm 11,1 as a dielectric sandwiched between
Charge is accumulated in 2.

The average surface roughness of both surfaces of the PPS films 11 and 12 used at this time is 0.04 μm or more, and the moisture resistance can be improved.

As described above, according to this embodiment, PPS as a dielectric material
Average surface roughness of both surfaces of film 11.12 'io, 0
Moisture resistance can be improved by setting the thickness to 4 μm or more. Next, a second embodiment of the present invention will be described with reference to the drawings. FIG. 2 shows a film configuration diagram of a capacitor in a second embodiment of the present invention. Reference numeral 11 denotes a dielectric PPS film, and a stain electrode is formed on one side of each PPS film 11 by vacuum deposition. 13 indicates an electrode. In this example, the only difference is the method of forming the electrodes.
There is no difference in operation and effect from Fig. 1.

The effect of the configuration of the present invention will be explained with reference to the drawings.

Figure 3 shows the results of the humidity test, where the vertical axis shows the difference (rate of change) between the capacitance before the test and the capacitance after the test, and the horizontal axis shows the P
It represents the average surface roughness of both surfaces of the PS film. The test conditions were a temperature of 60°C, a relative humidity of 96°C, and a time of 780°C.
It's time. As a result, the average surface roughness 'io, 04μ
It can be seen that when an AA electrode film is formed by vacuum evaporation on a film set to less than m, the capacitance changes significantly. Generally, the capacitance change after a humidity test is +1.0% due to the dielectric constant of water, since the film itself has the property of absorbing water.
It is distributed from 0 to +1.6 t. However, the results for less than 0.04 μm show a large variation in the negative direction (one direction).

This phenomenon means that corrosion and electrolytic corrosion of the pAl electrode progressed due to moisture, and the electrode no longer functioned as an electrode. Moreover, since the adhesive force between the film and the Ae electrode film is weak, corrosion and electrolytic corrosion proceed simultaneously from both sides of the film interface and the electrode surface, and the rate of corrosion is accelerated.

When the average surface roughness is 0.04 μm or more, the adhesion surface area with the Ad electrode film increases, so that the mechanical adhesion strength is increased, and the moisture resistance becomes stable in its flat form.

From the above, in order to improve the moisture resistance properties, it is necessary to set the average surface roughness of both surfaces of the PPS film to 0.04 μm or more.

Effects of the Invention As described above, the present invention can be used as a dielectric film for pps'
4, and by setting the average surface roughness of both surfaces of the PPS film to 0.04 μm or more, the moisture resistance can be improved and stabilized, which has great practical effects.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram of a capacitor according to an embodiment of the present invention;
FIG. 2 is a block diagram of a capacitor according to another embodiment of the present invention, FIG. 3 is a characteristic diagram of the capacitor of the present invention, and FIG. 4 is a block diagram of a conventional capacitor. 11...Metalized PPS film, 12...
...Non-metalized PPS film, 13... Electrode. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
Figure 11...4 mu vPPs? Fig. 2 to υ Fig. 3 (Moisture resistance test starting fruit (6θ'eβ'3.'?/-175
0Hz & overload 0.62 6.64 17J
4 11.08 el, 1 average Australia 1 ■ Milk 01 #1] Figure 4

Claims (3)

[Claims] (1) A capacitor characterized in that polyphenylene sulfide is used as a capacitor dielectric film, and the average surface roughness of both surfaces of the polyphenylene sulfide film is 0.04 μm or more. (2) Combine double-sided metallized film and non-metalized film,
The capacitor according to claim 1, characterized in that the capacitor is wound or laminated. (3) The capacitor according to claim 1, characterized in that a single-sided metallized film and a single-sided metalized film are combined and wound or laminated.