JPS6015143B2 - capacitor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to electrolytic capacitors used in electrical circuits, particularly audio equipment, and other case-housed capacitors.

In recent years, electronic components used in audio systems, such as capacitors, have been designed with a focus on electrical characteristics.However, with the development of audio technology, not only electrical characteristics but also It is well known that emphasis has been placed on the evaluation of sound quality.

Under these circumstances, capacitors housed in cases, such as electrolytic capacitors in particular, are electronic components that have a lot of room for improvement because they greatly affect the sound quality of audio equipment due to differences in components, structure, etc. In a conventional electrolytic capacitor, as shown in Fig. 1, an external lead terminal 1 is connected to an anode foil and a cathode foil by crimping or the like, and then the capacitor element 2 is formed by winding the anode foil and the cathode foil through electrolytic paper. death,
Next, the element 2 was impregnated with an electrolytic solution, a sealing body 3 made of rubber or the like was attached, and the element 2 was inserted into a case 4 made of aluminum or the like, and the open part of the case 4 was wrapped and sealed.

However, when a high frequency current is passed through such an electrolytic capacitor, in general, in the case of a metal case such as aluminum, an extremely small loop current is generated due to the magnetic flux caused by winding the aluminum electrode of the capacitor element, although it is not as strong as with magnetic metal. Occurs at the bottom of a metal capacitor case. Regarding sound quality in audio technology, it is well known that this loop current is a major cause of sound quality distortion. Therefore, in order to eliminate this loop current, the bottom of the cylindrical metal capacitor case is eliminated and a cylindrical metal pipe is used with the bottom made of rubber bake or resin, or the bottom is made of rubber bake or resin instead of a metal case. Cases made of non-conductive materials are currently being used, but they are currently faced with many obstacles, such as an increase in man-hours and the inability to use existing equipment. Furthermore, with conventional electrolytic capacitors housed in cases made of non-conductive materials such as glass or polypropylene resin,
After applying the paste to the capacitor element and applying the rated voltage to the electrodes of the element, we measured the potential difference between the top lead extraction side and the bottom side of the element. The potential is high and a potential difference of several mV to several hV may occur, and since these materials are dielectrics, dielectric loss occurs due to the alternating current electric field caused by the capacitor elements housed therein.

Due to the potential difference and loss of power inside the case, when a capacitor is used in an audio amplifier, the resolution of the reproduced sound will be reduced.
Difficulties arose in terms of the degree of separation of instruments, etc. The present invention solves these conventional problems, and provides a capacitor that reduces or eliminates loop current, suppresses dielectric loss, and eliminates potential difference inside the case by forming a carbon powder layer on the inner surface of the case. With the goal. The present invention will be described below with reference to an embodiment of an electrolytic capacitor shown in FIG.
A capacitor element 12 is formed by connecting external lead terminals 11 to the anode foil and the cathode foil by a method such as curling, and winding or laminating them with electrolytic paper interposed therebetween.

[〇- Also, a carbon powder layer 15 of polycrystalline graphite powder is uniformly formed in advance on the inner surface of the bottomed cylindrical aluminum case 14.

The capacitor element 12 is housed in the case 14, and the opening of the case is sealed with cotton wrapping.

By configuring as described above, the capacitor element 12
The magnetic flux generated perpendicularly to the bottom surface of the capacitor case 14 is prevented by the paramagnetism of the carbon powder layer 15 on the bottom surface of the capacitor case 14, and its path is bent instead of permeating vertically. The resulting loop current decreases or disappears, presumably because the carbon powder layer 15 acts as an electrostatic shield.

In the above embodiment, the carbon powder layer on the inner surface of the case 14 is
In the figure, it is formed on a part of the case, but it may be formed on the entire surface or only a small part such as the bottom. Furthermore, the carbon powder layer formed on the inner surface of the case is not limited to polycrystalline graphite powder, but may also be a layer of carbon powder such as acetylene black, carbon black, or activated carbon. There is. This is because when carbons such as graphite are ground, carbon-carbon bonds are broken, causing a large change in magnetic susceptibility and inducing paramagnetism. Furthermore, by subjecting the various ground carbons to a heat treatment of 400 to 700 qo, a large difference in magnetic receptivity occurs and the effect is further improved.
Next, FIG. 3 shows distortion factor characteristics of the capacitor of the above embodiment and a conventional capacitor (both rated at 50 WV, 1000 F).

In Fig. 3, the capacitor of this example is small, and (b) is the conventional product.As is clear from the figure, the capacitor of this example
It can be seen that the distortion rate at 0 KHZ is significantly improved, and there is a remarkable effect. In addition, as shown in Fig. 4, the capacitor of this embodiment was used as a coupling capacitor between the preamplifier 16 and the main amplifier 17 of an audio system, and as a result, it was found to be more intelligent and playable compared to the conventional capacitor. It has been demonstrated that the sound quality is excellent in terms of scale image power and sound quality. FIG. 5 shows another embodiment,
The case 14 shows an electrolytic capacitor made of polypropylene resin.

Components with the same reference numerals as in FIG. 2 have the same functions. In this embodiment, since the graphite carbon powder layer 15 formed on the inner surface of the case 14 exhibits appropriate conductivity, the potential difference within the case 14 is eliminated, the potential is made uniform, and power transfer loss is also suppressed. This improves capacitor characteristics.

When the capacitor of this embodiment and the conventional electrolytic capacitor with a polypropylene resin case are used in the circuit shown in Figure 4, and the difference in intelligence is compared, It has been demonstrated that it has excellent characteristics in terms of sound quality.

As described above, the present invention forms a carbon powder layer on the inner surface of the case, so the characteristics of the carbon powder layer, such as magnetism, conductivity, and appropriate electrical resistance, reduce and eliminate loop current, suppress dielectric loss, It is possible to eliminate the potential difference on the inner surface of the case, and improve the characteristics of the capacitor itself. Moreover, in this configuration, it is sufficient to simply form a carbon powder layer on the inner surface of the case, so there is no need to make any major changes to the conventional capacitor manufacturing process, and productivity is also excellent. In the embodiments of the present invention, only the case of a Hakurin capacitor has been described, but if the characteristics of carbon powder and its effect on the case are taken into account, the capacitors to be housed in the case, such as wound type, laminated type, porcelain, etc. It can be widely applied to various condensers regardless of their case materials.

[Brief explanation of the drawing]

Fig. 1 is a cross-sectional view of a conventional electrolytic capacitor, Fig. 2 is a cross-sectional view of an aluminum case electrolytic capacitor according to an embodiment of the present invention, Fig. 3 is a distortion factor characteristic diagram of the above embodiment, and Fig. 4 is a diagram of the same implementation as above. FIG. 5 is a circuit diagram showing an example of a characteristic testing device, and a sectional view of a resin case electrolytic capacitor according to another embodiment of the present invention. 12... Capacitor element, 14... Capacitor case, 15... Carbon powder layer. Figure 1 Figure 2 Figure 3 Figure 4 Figure 5

Claims (1)

[Claims] 1. A capacitor characterized in that a carbon powder layer is formed on at least the bottom of the inner surface of a case that houses a capacitor element.