JPH01115114A - Wound type capacitor - Google Patents

Abstract

PURPOSE:To form a non-inductive wound type capacitor by a method where in a plurality of electrode thin-film pairs are arranged and wound vertically zigzag, holding a dielectric thin-film, electrode loading-out sections shaped to electrode thin-films at both winding ends are connected to the outside, and used as one electrode leading- out sections, and electrode leading-out sections formed to electrode thin-films at the center are employed as the other electrode leading-out sections. CONSTITUTION:A plurality of at least one dielectric thin films 11 and electrode thin- film pairs 12a-12d, 13a-13c oppositely faced, holding the dielectric thin films 11 are mutually disposed zigzag in the direction of winding and wound. The electrode thin-films 12a, 12d at winding-start ends and winding finish ends in the electrode thin-film pairs 12a-12d,13a-13c are brought to the same potential by external connection and used as one electrode leading-out sections, and the electrode thin-films 13b at the center are employed as the other electrode leading-out sections. Consequently, currents applied to a capacitor flow from the electrode thin-films at both winding ends to the electrode thin-films at the center or from the electrode thin-films at the center to the electrode thin-films at both winding ends through a formed series capacitance. Accordingly, induced magnetic fields are offset, and the generation of induced reactance can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to wound capacitors used in relatively high voltage circuits.

2. Description of the Related Art] Wound capacitors are widely used as I-structure capacitors, in which a strip-shaped electrode material and a dielectric material are stacked one on top of the other. In this type of capacitor, the electrode material is metal foil such as aluminum with strip-shaped slits,
A strip-shaped film is used that is made of a dielectric film such as paper or plastic with aluminum or zinc vapor-deposited on it. On the other hand, as dielectric materials, paper and plastic films are used either in China or in combination.

When this wound type capacitor is used in a circuit that requires a relatively high voltage, it is common to connect a plurality of capacitors in series externally to achieve an allowable withstand voltage as a whole. However, as a matter of course, such a capacitor has a large shape. On the other hand, a method of forming a plurality of capacitors in one capacitor element by devising the winding structure has been considered. Generally, such a structure is called a horizontal staggered configuration or a vertical staggered configuration depending on the method of combination. Although this staggered configuration winding capacitor has a high allowable withstand voltage,
Its feature is that its shape can be made relatively small. In addition, especially in the case of a wound capacitor with a vertically staggered configuration, the electrode length in the winding direction becomes longer because the unit capacitors are formed in series in the winding direction, and the inductive reactance that occurs when used in a high frequency circuit increases. can no longer be ignored.

As an example of a conventional wound capacitor with a staggered configuration, a three-stage series capacitor with a vertical staggered configuration is shown in Figure 3 (a) and (b).
Shown below. In FIG. 3(a), electrode thin films 2a, 2b and electrodes i[3a, 3b are arranged to face each other with dielectric 1 in between. Electrode W! 12a, 2b and 3a, 3b
G;t, and 1cv-gin 4 are arranged. Here, the total capacitance is a capacitance IC1 made up of electrodes 2b and 3b facing each other with the same dielectric 1 in between, a capacitance ff1c2 made up of facing electrodes 3a and 2b, and a capacitance ff1c2 made up of facing electrodes M film 2a. Three capacitors of capacitor ff1c3 consisting of and 3a are connected in series. Here, the electrode group rIA2
Reference character a is the electrode i1 film at the start end of winding, and electrode thin film 3b is the electrode thin film at the end end of winding, which protrude from opposite side ends of the dielectric 1 and serve as electrode extraction parts. In a wound capacitor formed with this arrangement,
The applied external voltage is the electrode group! 12a and 3b, the voltage applied to dielectric 1 is C1, 02, and 03.
As a result, the pressure is divided by three capacitances, C1 and 02
When formed so that C3 and C3 are the same, the allowable withstand voltage of the dielectric 1 is -3/3 of the applied external voltage. FIG. 3(b) shows a wound type capacitor formed by winding the capacitor in the state shown in FIG. 3(a) above around a winding core 5.

Problems to be Solved by the Invention However, in the wound type capacitor having the above structure, the electrode membranes 2b and 3a are not electrode lead-out portions, so when a voltage is applied to the electrode membranes 2a and 3b, the capacitance ff101~C3
becomes a conductive path connecting the electrode thin films 2a and 3b through the
Furthermore, because they are wound, they produce inductive reactance when used in an AC circuit. Particularly in high frequency circuits, this induced component becomes larger than the capacitor's original capacitance, making it undesirable as a capacitor.

The present invention solves the above-mentioned problems, and aims to provide a wound capacitor that has a vertically staggered configuration and does not generate inductive reactance.

Means for Solving the Problems In order to solve the above problems, the wound capacitor of the present invention has a plurality of electrode thin film pairs arranged and wound in a vertically staggered manner with a dielectric sandwiched between the electrodes. In addition to the conventional electrode y# film at the start end of winding and the electrode thin film at the end of winding, take-out parts are also provided in the center electrode thin film, and among these three electrode take-out parts, the electrodes of the electrode thin films at both winding ends are provided. The lead-out part is externally connected to serve as one electrode lead-out part of the completed capacitor, and the electrode lead-out part of the central electrode thin film is used as the other electrode lead-out part.

Operation In the above configuration, the current applied to the capacitor passes through the formed series capacitance from the electrode thin films at both winding ends to the central electrode IWi, or from the central electrode N film to the electrode thin films at both winding ends. As a result, the directions of current swirl in the central electrode thin film and the electrode thin films at both winding ends are opposite to each other, and the directions of the magnetic fields induced on both sides are also mutually opposite.As a result,
It can cancel out the induced magnetic field and eliminate inductive reactance, and is non-inductive in any high-voltage, high-frequency circuit.

EXAMPLE An example of the present invention will be described below based on the drawings. 1st
Figures (a) and (b) show a wound capacitor according to an embodiment of the present invention, in which (a) is a perspective view of tRN before winding, and (b) is a schematic perspective view after winding. In FIG. 1(a), electrode films 12a, 12 are arranged in the winding direction with the dielectric film 11 in between.
b, 12c, and 12d are also opposed to the electrodes 1rIi! 13a, 13b, and 13c are arranged and stacked in a staggered manner with an inter-thin film margin 14 and an outer margin 15, respectively. This is then wound around a winding core 16 as shown in FIG. 1(b) to form a wound capacitor A. In this winding state, among the electrode thin films, the electrode thin film 12a at the beginning of winding and the electrode thin film 12d at the end of winding are connected externally and become one electrode extraction part of the completed capacitor. The electrode membrane 13b corresponding to the English part serves as the other electrode extraction part. In a wound type capacitor having such a structure, for example, when a high frequency current is applied from the central electrode lead-out portion of the thin film electrode 13b, the applied current is partially transferred from the electrode thin film 13b to the electrode via the capacitors ff1c11a, Cl2a, and C13a. It passes through the thin films 12b and 13a, reaches the electrode film 12a, and exits to the external circuit of the capacitor. On the other hand, the remaining current flows from the electrode WI film 13b to the capacitors Qjlb and Cl2b.

It reaches the electrode thin film 12d via Q13b, the electrode thin films 12c and 13c, and joins the current coming out from the electrode thin film 12a in an external circuit. At this time, by adjusting the length of the electrode base film so that the capacitance of both paths becomes equal, the current flowing through both paths can be made the same.

In addition, since the electrode 'S films of both these paths are arranged on the same dielectric material and are wound in the same direction,
The directions of current flowing in both paths are opposite to each other. On the other hand, the inductive reactance generally induced in a wound capacitor is caused by a thin wound conductive electrode, II! This is due to the current flowing through. Therefore, in the wound capacitor of this embodiment shown in FIG. 1(b) above, since the same current flows in the same capacitor in mutually opposite directions, the directions of the magnetic fields induced in both directions are also mutually opposite. Overall, the induced magnetic field in the capacitor is canceled out,
As a result, no inductive reactance occurs. Although the explanation has been given here assuming that power is supplied from the central electrode thin film, the same result can of course be obtained even if power is supplied from the electrode thin films on both winding ends.

The above embodiment will be explained in detail below. That is,
In FIG. 1(A), the dielectric thin film 11 is made of polyethylene terephthalate having a width of 20 μl and a thickness of 36 μl.

The electrodes 1Jl112b, 12c, 13a, and 13c arranged on both sides of the PET film were made of aluminum foil with a width of 10 cm and a thickness of 7 μm, and an outer margin 15 of 5 rMl on both sides of the dielectric thin film 11 was provided. , and were further stacked so as to face each other for a required length and to be arranged in a staggered manner with an inter-stage margin 14 in between. Also, electrode thin 1 [112
a.

12d is made of aluminum foil with a width of 2011 mm, a thin margin 14 is provided on both sides of the electrode films 12b and 12c, and both electrode films 12b and 12c are provided with a thin margin 14 from the side edge Ha on the same side of the dielectric thin film 11.
The electrode thin film 13b has a width of 20 mm.
gs! of the dielectric thin film 11 on the opposite side from the electrode thin films 12a and 12d. 511 was arranged and stacked so as to protrude from llb. This laminate and another dielectric thin film were wound around a winding core 16 to form a wound capacitor 8 shown in FIG. 1(b). In FIG. 1(b), the protruding electrode thin films 12a and 12d are combined with the side surface A1 of the wound capacitor A to form one electrode of the capacitor, or the protruding electrode film 1
The protruding portion of 3b was also pushed into the other side surface A2 of the wound capacitor A to serve as the other electrode. After attaching lead wires to these electrodes, the entire structure was molded with IWi.

FIG. 2 shows another embodiment, in which conductive material is deposited on both sides of a dielectric film in a staggered manner so as to face each other, and the film is wound. That is, the dielectric thin film 21
Polypropylene (PP) is used for this dielectric thin film 2.
1 (a) using aluminum as the ffi conductive material on both sides of the substrate.

An electrode thin film was formed by providing an inter-thin film margin 24 and an outer margin 25 so as to have the same pattern as in Example (b). Of these electrodes ina, as shown in FIG.
The tab 27 is placed on the electrode [123b] with the tab 27 on the side of the electrode i1 films 22a and 22d.
6a and 26b protruding from the side end 21b on the opposite side and overlapped, and wound around the winding core together with another dielectric thin film.
A wound capacitor (not shown) similar to that shown in Figure (b) was formed. Further, as in the above embodiment, the tab 26a
, connect the protruding parts of 26b to the lead wire,
Further, the tab 27 was also connected to another lead wire, and then the whole was molded with resin.

The effects of both of the above embodiments will be explained in comparison with the conventional example shown in FIGS. 3(a) and 3(b). Figure 3 (a).

In the conventional wound capacitor with a vertical staggered configuration shown in (b), the electrode extraction portion is the electrode 1 film row 2a.

The electrode thin films 2a, 3b at both winding ends of 3a, 2b, 3b, the current supplied from one of the electrode thin films flows out from the other electrode, so the electrode thin film array is wound in one direction. In a wound capacitor, a swirling current occurs and a unidirectional magnetic field is generated, resulting in an inductive actance. This inductive reactance is S! Is the voltage applied low frequency? In the case of l voltage, this is hardly a problem as the value is extremely small compared to the capacitor's inherent capacitive reactance, but in the case of high frequency voltage, the inductive reactance exceeds the capacitive reactance and the circuit constant becomes undecided.

On the other hand, in the wound type capacitor according to the embodiment of the present invention shown in FIGS. 1(a) and 1(b), the electrode thin film arrays 12a, 13a, 12b, 13b, t2c are arranged as described above.

The electrode thin film 13b at the center of 13c and j2d and the electrode 1 films t2a and 12d at both winding ends of the electrode thin film array serve as electrode extraction parts, and the electrode thin film 11:! Since 12a and 12d are connected externally and become the same electrode, for example, the current supplied from the electrode thin film 13b is transferred to the electrode i1 film 13b-12.
b -13a -12a path and electrode 111113a
-12cm 13c -12cj It flows through two paths and flows out to the outside. Moreover, these electrode thin film arrays are made of the same dielectric material III! ! 111 and are wound in the same direction, the direction of current flow is opposite to each other in each path, and the direction of the magnetic field induced by each swirling current is also opposite.
If the electrode thin film array is formed so that the current and number of turns in both paths are the same, the magnetic field induced in the wound capacitor as a whole can be canceled out, and as a result, inductive reactance is eliminated.

Since this effect does not depend on the frequency of the applied alternating It voltage, it can be used as a non-inductive capacitor in any high frequency circuit. Furthermore, the vertically staggered configuration has the effect of dividing the applied voltage into series, and can be used in any high voltage circuit. As an example of a specific effect, a 60μH2 high frequency When a voltage was applied, the inductive reactance was 0.32 μH. On the other hand, in the embodiment shown in FIGS. 1(a) and 1(b), 6
It is a vertical staggered-wound capacitor, but in order to supply power to the center electrode, for example, the voltage is two 3-stage staggered wound capacitors connected in parallel, which is the same as the conventional type above. However, the inductive reactance when applying a high frequency voltage of 60 MHz was 0.08 μH. This glue actance of less than 0.1 μH is equivalent to 60 μH for a single-layer ceramic capacitor with lead wires of approximately the same length.
Judging from the fact that the inductive reactance when a high frequency voltage of μH2 was applied was 0.1 μH, this is considered to be the pure reactance of the electrode lead wire.

As described above, in the wound capacitor of the above embodiment, a high voltage withstand non-inductive capacitor can be easily manufactured, and it can replace ceramic capacitors that have conventionally been applied to high voltage and high frequency circuits. By taking advantage of the characteristics of film capacitors, it will be easy to improve the temperature dependence of capacitance and reduction of dielectric loss, which were drawbacks of conventional ceramic capacitors.

As mentioned above, the present invention relates to a wound capacitor having a vertically staggered configuration and a feature of electrode extraction portions, and the materials and shapes related thereto are not limited in any way to the above embodiments. . Further, in the above description of the present invention, only a three-stage staggered configuration was described, but the same effect can be obtained even with a structure with more stages than three stages.

Effects of the Invention As described above, in the wound capacitor of the present invention, the applied current is passed through the formed series capacitance from the electrode thin film at both wound ends to the central electrode thin film, or from the central electrode thin film to the central electrode thin film. Since the current flows from one membrane to the electrode 'am at both ends, the direction of current rotation is opposite between the center electrode # membrane and the electrode thin films at both ends, and the direction of the magnetic field induced on both sides is also opposite. They are opposite to each other, canceling out the induced magnetic field and causing no inductive reactance. In addition, it can be used as a non-inductive capacitor in any high-frequency circuit, and has a high withstand voltage, replacing the ceramic capacitors conventionally used in high-voltage and high-frequency circuits. It can be used as a capacitor with reduced dielectric loss.

[Brief explanation of the drawing]

1(a) and (b) show a wound capacitor according to an embodiment of the present invention, (a) is a schematic perspective view before winding, (b) is a schematic perspective view of W1 after winding, FIG. 2 is a schematic perspective view of a wound capacitor according to another embodiment of the present invention before winding, and FIG. 3 (A)
, (B) shows a conventional example, (A) is a schematic perspective view before winding, and (B) is a schematic perspective view after winding. 11, 21... dielectric thin film, 12a, 12b, 1
2c, 12d. 13a, 13b, 13G, 22a, 22b, 22G, 2
2d. 23a, 23k), 23c ・*7ff ultra-thin film. Agent Yoshihiro Morimoto

Claims (3)

[Claims] 1. At least one dielectric thin film and a plurality of electrode thin film pairs facing each other with the dielectric thin film in between are arranged in a staggered manner and wound in the winding direction, and among the plurality of electrode thin film pairs, A wound type capacitor in which the thin electrode films at the beginning and end of the winding are externally connected to have the same potential, and the thin electrode film in the center is used as the other electrode lead-out part. 2. Aluminum foil is used as the electrode thin film, and the foil at the electrode take-out part is made to protrude to opposite sides of both ends of the dielectric thin film at the electrode take-out parts at the start end, the end end of winding, and the central electrode take-out part. In addition to arranging
The wound capacitor according to claim 1, in which the foils at both ends of the winding protrude in the same direction in a wound state are overlapped to form the same electrode. 3. A vapor-deposited electrode thin film is formed by vapor-depositing a conductive substance on a dielectric thin film as an electrode thin film, and an aluminum foil or tab is placed on the vapor-deposited electrode thin film at the electrode extraction part, and the electrode is extracted from the winding start end and the winding end end. At the electrode extraction section and the central electrode extraction section, the dielectric thin film is attached so that it protrudes to opposite sides of both ends of the dielectric thin film, and the foils or tabs of both winding ends that protrude in the same direction in the wound state are overlapped to form the same electrode. A wound capacitor according to claim 1.