JPH088140A - Dc high-voltage capacitor - Google Patents

Abstract

PURPOSE:To provide a small-sized economic DC high-voltage capacitor having an improved charge-discharge characteristic, in the DC high-voltage capacitor having the structure wherein a plurality of capacitors are connected in series with each other inside one capacitor element. CONSTITUTION:The capacitor element of a DC high-voltage capacitor is configured by the double winding of plastic films 1, 6. The plastic film 1 is the one wherein deposition film electrodes 2 and aluminium foils 4 are provided respectively and its Izod impact strength is not larger than 1000kg-cm/m and its flexural strength is not larger than 1000kg/cm<2>. The plastic film 6 is the one wherein its Izod impact strength is not smaller than 1000kg-cm/mm and its flexural strength is not smaller than 1000kg/cm<2>.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a DC high voltage capacitor used in a high voltage section of a CRT display device or a flyback transformer of a television receiver.

[0002]

2. Description of the Related Art FIGS. 3A and 3B show a conventional capacitor. Conventionally, a DC high-voltage capacitor of this type has a pair of metallized films in which an electrode vapor deposition film 2 is formed on a pair of plastic films 1 forming a dielectric and gap insulating portions 3 are provided at predetermined intervals in the longitudinal direction. , The vapor deposition film electrodes 2 are arranged so as to face each other and wound, and aluminum foils 4 are arranged at the electrode positions of the winding start and the winding end, and the electrodes are drawn out to connect a plurality of capacitors in series in one element. It has been configured. The pair of plastic films 1 has an Izod impact strength represented by a polypropylene film (hereinafter abbreviated as PP) of 1000 kg · cm / m.
A combination of plastic films of m or less and a bending strength of 1000 kg / cm ² or less has been adopted. In addition, a combination of plastic films having an Izod impact strength of 1000 kg · cm / mm or more and a bending strength of 1000 kg / cm ² or more, which is represented by polyethylene terephthalate (hereinafter abbreviated as PET), was adopted as a pair of plastic films. .

Further, when a capacitor made of a combination of PP is used in a high voltage circuit such as a CRT display device, a resistor is connected in series with the capacitor in order to protect the capacitor from a voltage and a current caused by a transient phenomenon during discharge in a cathode ray tube. . In the figure, 5 is a lead.

[0004]

However, in general, in the manufacturing process of a capacitor, vacuum heating aging is performed to stabilize its quality, but when it is wound around a pair of plastic films constituting a dielectric using PP,
Due to the heat shrinkage of the PP film during vacuum heating, the edge stress of the aluminum foil 4 of FIG. 3 which is an electrode portion is concentrated on the facing vapor deposition film electrode 2 and the vapor deposition film electrode 2 is broken as shown in FIG. A high resistance portion is generated in the area, and the current capacity of the cross section of the vapor deposition film electrode 2 in the winding direction decreases. Therefore, when the protective resistor is removed from the capacitor having the above-mentioned structure, a large current flows due to a transient phenomenon at the time of discharge in the tube, and the locally high resistance portion of the vapor deposition film electrode 2 is melted down in the width direction of the plastic film 1 to remove the capacitor. I was worried if I was destroyed.

In order to prevent this destruction, it is necessary to increase the mechanical strength by increasing the thickness of the plastic film 1 serving as a dielectric in the above-mentioned capacitor, or to reduce the thickness of the aluminum foil 4. When the thickness of the film 1 is increased, the material cost becomes high, which is uneconomical, and the volume of the capacitor is greatly increased, which restricts the miniaturization of the equipment used.

Further, if the thickness of the aluminum foil 4 is reduced, the yield at the time of winding the capacitor is extremely reduced and wrinkles are formed, which causes a problem with the quality of the capacitor. Furthermore, when PET is used for the pair of plastic films 1 forming the dielectric, the edge stress of the aluminum foil 4 does not occur unlike the case of PP, and the locally high resistance part of the vapor deposition film electrodes 2 facing each other does not occur. Therefore, the current capacity does not decrease, and even if a large current flows due to a transient phenomenon at the time of in-tube discharge, the vapor deposition film electrode 2 does not melt down, but the PET film has a pressure resistance at the same film thickness as PP, It has the drawback of being inferior in moisture resistance. Therefore, in order to obtain the same level of pressure resistance and moisture resistance as the PP film, it is necessary to increase the film thickness or dip the element end face with resin, which results in higher material costs than PP and the resin on the element end face. It was not economical because the dip man-hours increased. The present invention has been made in consideration of the above conventional problems, and an object of the present invention is to provide a DC high-voltage capacitor having good charge / discharge characteristics, small size, and economical.

[0007]

In order to solve the above problems, the present invention provides a plastic film which constitutes an element,
A film with an Izod impact strength of 1000 kg · cm / mm or less and a bending strength of 1000 kg / cm ² or less and a film with an Izod impact strength of 1000 kg · cm / mm or more and a bending strength of 1000 kg / cm ² or more are used. Then, the vapor deposition film electrode is provided on one side of each film, and the aluminum foil is provided on the former film side for winding, or the vapor deposition film electrode and the aluminum foil are provided on both sides of the latter film for winding with the former film attached. It will be rotated.

[0008]

With the above structure, no stress is applied to the vapor-deposited film electrodes facing the edge of the aluminum foil, the current capacity of the vapor-deposited film electrodes is not reduced, and there is no fusing breakage. For this reason, the protection resistor is not required, and not only the size of the flyback transformer can be reduced, but also the man-hours for mounting the protection resistor are reduced, which leads to cost reduction and can supply an economical DC high voltage capacitor.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. In addition, the same reference numerals are given to those having the same functions as those of the conventional capacitor, and the description thereof is omitted.

As shown in FIG. 1, the capacitor element is
Izod impact strength of 1000k on a plastic film
g · cm / mm or less and bending strength of 1000 kg /
cm ² PP films represented by the following plastic films
Film 1 and Izod impact strength is 1000 kg · cm
/ Mm or more and bending strength of 1000 kg / cm²Since
PET film represented by the above plastic film
It is configured by winding using 6.

In the winding structure of the PP film 1 and the PET film 6 described above, due to the characteristics of each film, the stress applied to the vapor deposition film electrode 2 facing the edge portion of the aluminum foil 4 provided on each film is generated. Moreover, since the current capacity at the time of discharge is secured, there is no fusing breakage.

FIG. 2 shows the results of a charge / discharge test at DC 30 kV between the product of this example and a conventional capacitor at 1500 pF designed so that 10 unit capacitors are connected in series. 20 μm of PP film 1 was used for one film of the product of the present example and the conventional product, PET film 6 of 20 μm was used for the other film of the present example, and the same PP film was used for the conventional product.

Here, in the conventional capacitor, a local high resistance portion is generated due to the stress applied to the vapor-deposited film metal 2 where the edge portion of the aluminum foil 4 is opposed, and the current capacity of this portion is lowered to cause the fusing and breaking. I was worried if I was destroyed.
However, in the capacitor of this example, the locally high resistance portion of the deposited film metal 2 due to the stress at the edge portion of the aluminum foil 4 did not occur, and the capacitor was not destroyed. From these results, it can be seen that the charge and discharge characteristics of the capacitor of this example are at an extremely high level as compared with the conventional capacitor.

Further, the volume ratio of the capacitor of this embodiment is 100: 65 when the PP film thickness of the conventional capacitor is 30 μm so as to have the same charge / discharge characteristics as the capacitor of this embodiment. Capacitors can be made smaller than before.

Further, since the conventional capacitor has a PP film thickness of 30 μm so as to have the same charge / discharge characteristics as the capacitor of this embodiment and the direct material cost of the capacitor of this embodiment is 100: 68. It was found that the capacitor of this example was economical.

[0016]

As is apparent from the above description of the embodiments, according to the present invention, the plastic film constituting the capacitor element has an Izod impact strength of 1000 kg · cm /
mm or more and bending strength of 1000 kg / cm ² or more of film and Izod impact strength of 1000 kg · cm
/ Mm or less and a flexural strength of 1000 kg / cm ² or less, the charge and discharge characteristics can be improved, and a safe and economical capacitor can be provided.

[Brief description of drawings]

1A and 1B are cross-sectional views of a capacitor according to the present invention.

FIG. 2 is a graph showing the results of charge and discharge tests at a DC of 30 kV for a capacitor of one example according to the present invention and a conventional capacitor.

3A and 3B are cross-sectional views of a conventional capacitor, respectively.

FIG. 4 is a sectional view of an aluminum foil edge portion of a conventional capacitor.

[Explanation of symbols]

 1 PP film 2 Evaporated film electrode 3 Gap insulating part 4 Aluminum foil 5 Lead 6 PET film

Claims (2)

[Claims] 1. A vapor deposition film electrode is formed on one surface of a plastic film, and the vapor deposition film electrode is opposed to a pair of single-sided metallized films provided with a plurality of gap insulating portions at predetermined intervals in the longitudinal direction. To be wound simultaneously, or vapor-deposited film electrodes are formed on both sides of a plastic film, and the vapor-deposited film electrodes are provided with a plurality of gap insulating portions at predetermined intervals in the longitudinal direction at different positions from the respective surfaces. DC high-voltage capacitor with a structure in which a plurality of capacitors are connected in series within one element by winding a synthetic film and a plastic film at the same time, arranging aluminum foil at the electrode positions at the beginning and end of the winding and pulling out the electrodes The Izod impact strength (JIS K6745 72) is 1000 kg on the single-sided metallized film on the side where the aluminum foil is arranged.
-Cm / mm or less and bending strength (ISO-R17
8) uses a plastic film of 1000 kg / cm ² or less, and uses a plastic film having an Izod impact strength of 1000 kg · cm / mm or more and a bending strength of 1000 kg / cm ² or more for the opposing one-sided metallized film. Characteristic DC high voltage capacitor. 2. A vapor-deposited film electrode is formed on one surface of a plastic film, and the vapor-deposited film electrode faces a pair of single-sided metallized films provided with a plurality of gap insulating portions at predetermined intervals in the longitudinal direction. To be wound simultaneously, or vapor-deposited film electrodes are formed on both sides of a plastic film, and the vapor-deposited film electrodes are provided with a plurality of gap insulating portions at predetermined intervals in the longitudinal direction at different positions from the respective surfaces. DC high-voltage capacitor with a structure in which a plurality of capacitors are connected in series within one element by winding a synthetic film and a plastic film at the same time, arranging aluminum foil at the electrode positions at the beginning and end of the winding and pulling out the electrodes , The Izod impact strength (JIS K6747572) of the double-sided metallized film constituting the device is 1000 kg · cm /
mm or more and bending strength (ISO-R178) is 10
Using a plastic film of 00 kg / cm ² or more,
A direct current high voltage capacitor, which is obtained by winding a plastic film having an Izod impact strength of 1000 kg · cm / mm or less and a bending strength of 1000 kg / cm ² or less on a plastic film which is wound at the same time.