JPH1167602A - Capacitor and manufacturing method thereof - Google Patents

Abstract

(57) Abstract: An object of the present invention is to provide a capacitor using a conductive polymer having high dielectric breakdown voltage and excellent high-frequency characteristics as an electrolyte, and a method for manufacturing the same. SOLUTION: The present invention provides a pair of electrodes 12, 17 and the like provided facing each other, and a dielectric layer 1 provided between the electrodes.
And at least one of the electrodes has a conductive polymer layer 15 obtained by polymerizing a polymerizable monomer, and the conductive polymer layer is formed of a conductive polymer fine particle 14 or A capacitor whose thickness is increased by adding a cross-linked polyacrylic acid or a salt thereof, and a method of manufacturing a capacitor which provides such a capacitor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a solid electrolytic capacitor using a conductive polymer layer as a solid electrolyte.

[0002]

2. Description of the Related Art Recently, with the digitization of electrical equipment, the capacitors used therein have low impedance in the high frequency range, and there is an increasing demand for smaller and larger capacitors.

[0003] In order to answer those requests, 7,7,8,
A solid electrolytic capacitor using an organic semiconductor such as 8-tetracyanoquinodimethane (TCNQ) salt as a solid electrolyte is disclosed in JP-A-58-17609.

Further, Japanese Patent Application Laid-Open No. Sho 60-244017 discloses a polymer obtained by polymerizing a polymerizable monomer such as pyrrole or furan to obtain a conductive polymer, which is used as a solid electrolyte.

Further, after forming a dielectric comprising an electrodeposited polyimide thin film on an etched aluminum foil, a conductive polymer layer is sequentially formed by chemical polymerization and electrolytic polymerization to form a large capacity film capacitor as an electrode. (Proceedings of the 58th Annual Meeting of the Institute of Electrical Chemistry, pp. 251-252 (1991)).

[0006]

Although various types of capacitors are used as described above, solid electrolytic capacitors using an organic semiconductor such as a TCNQ salt have high-frequency characteristics superior to those using manganese dioxide. On the other hand, the loss coefficient and high-frequency impedance do not show ideal characteristics due to the increase in specific resistance when applying the organic semiconductor and the weak adhesion to the anode foil. .

When the conductive polymer layer is made of a solid electrolyte, the frequency characteristics, temperature characteristics, life characteristics, etc. are excellent.

In order to form the conductive polymer layer on the anode valve metal as described above, a chemical oxidation polymerization method using a polymerizable monomer solution and an oxidizing agent solution, and a solution containing a polymerizable monomer and a supporting electrolyte are used. Electrolytic polymerization method.

However, particularly in the case of the chemical oxidation polymerization method, the conductive polymer layer is less likely to adhere to the outer surface than the deep part of the electrode pores, and it is difficult to obtain a sufficient electrolyte layer thickness. There is a problem that the dielectric breakdown voltage is lower than that of a conventional solid electrolytic capacitor using manganese dioxide as an electrolyte.

An object of the present invention is to solve the above-mentioned technical problems, and an object of the present invention is to easily obtain a solid electrolytic capacitor having a high dielectric breakdown voltage using a conductive polymer as an electrolyte.

[0011]

SUMMARY OF THE INVENTION The present invention comprises a pair of electrodes provided to face each other and a dielectric layer provided between the electrodes, at least one of the electrodes being formed by polymerizing a polymerizable monomer. The conductive polymer layer thus obtained has a thickness that is increased by adding conductive polymer fine particles or cross-linked polyacrylic acid or a salt thereof in advance before the polymerization. Capacitor
This is a method for manufacturing a capacitor that provides such a capacitor.

With the above structure, a capacitor having a high dielectric breakdown voltage and excellent high-frequency characteristics and using a conductive polymer as an electrolyte can be easily obtained.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention according to claim 1 comprises a pair of electrodes provided to face each other, and a dielectric layer provided between the electrodes, wherein at least one of the electrodes is a polymerizable monomer. A conductive polymer layer obtained by polymerizing the conductive polymer layer, and the conductive polymer layer has a thickness by adding conductive polymer fine particles or cross-linked polyacrylic acid or a salt thereof in advance before the polymerization. Is an increased capacitor.

With this configuration, a capacitor having a high dielectric breakdown voltage and excellent high-frequency characteristics and using a conductive polymer as an electrolyte is obtained.

Here, the thickness of the conductive polymer layer is preferably at least 10 μm.

According to this configuration, not only the withstand voltage is improved but also the loss and the impedance are set to excellent values. In particular, when a conductive polymer layer is formed by chemical oxidative polymerization, it is possible to substantially prevent colloidal carbon from penetrating the conductive polymer layer and reaching the dielectric surface, so that dielectric breakdown occurs. A capacitor with a high voltage can be obtained.

It is preferable that the conductive polymer of the conductive polymer layer is polypyrrole, polythiophene, or polyaniline because of its high electric conductivity.

More specifically, as polythiophene,
3,4-ethylenedioxythiophene is exemplified.

It is preferable that the conductive polymer of the conductive polymer fine particles is polypyrrole, polythiophene, or polyaniline because of its high electric conductivity.

Here, more specifically, polythiophene includes 3,4-ethylenedioxythiophene.

As described in claim 5, it is also preferable that the conductive polymer of the conductive polymer layer and the conductive polymer of the conductive polymer fine particles are of the same type because of the simplicity of the structure.

The dielectric layer may be an oxide film of a valve metal, and the valve metal is preferably tantalum or aluminum. .

As the valve metal, for example, niobium, titanium, etc. may be used. In the case of tantalum or aluminum, more specifically, fine powdered porous tantalum sintered body, etched aluminum Foil may be used.

Further, as described in claim 8, the dielectric layer may be a polymer layer, and as in claim 9, the polymer of the polymer layer is preferably polyimide.

As described above, when the polymer layer is used as the dielectric, the polarity observed in the case of the oxide film of the valve metal is eliminated, and a bipolar capacitor is obtained.

Further, when a thin polymer layer is formed on, for example, an etched aluminum foil, a film capacitor having a significantly small size and a large capacity can be realized as compared with the prior art.

According to a tenth aspect of the present invention, a step of arranging a pair of electrodes facing each other, a step of arranging a dielectric film between the electrodes, and a step of forming a conductive polymer layer on at least one of the electrodes. Forming a conductive polymer layer, wherein the step of forming the conductive polymer layer is a method of manufacturing a capacitor including a step of adding conductive polymer fine particles or cross-linked polyacrylic acid or a salt thereof.

With this configuration, a capacitor having a high dielectric breakdown voltage and excellent high-frequency characteristics and using a conductive polymer as an electrolyte is provided.

Here, it is ensured that the step of forming the conductive polymer is a chemical oxidative polymerization step using a polymerizable monomer solution and an oxidizing agent solution. It is suitable because of its properties and simplicity.

In addition, as described in claim 12, the conductive polymer fine particles can be contained in at least one of a polymerizable monomer solution and an oxidizing agent solution, and in any case, the conductive polymer fine particles are contained in the conductive polymer layer. Provide an added capacitor.

The conductive polymer fine particles are attached to the surface of the dielectric, and the thickness of the conductive polymer layer formed by chemical oxidative polymerization can be easily increased by the action.

Further, the average particle diameter of the conductive polymer fine particles to be used is determined in order to reduce the variation in the thickness of the conductive polymer layer formed by chemical oxidation polymerization and to obtain desired high-frequency characteristics. It is desirable to use one of 1 μm or less.

According to a twelfth aspect of the present invention, the conductive polymer particles are arranged on the surface of the dielectric by adding the conductive polymer particles to at least one of the polymerizable monomer solution and the oxidizing agent solution. Things.

[0034] As described in claim 13, the method may further include a step of preparing conductive polymer fine particles by polymerizing a polymerizable monomer.
Provide conductive polymer fine particles reliably.

Here, as described in claim 14, the polymerizable monomer is preferably at least one selected from pyrrole, thiophene, aniline and derivatives thereof.

It is also preferable to use a polymerizable monomer solution in which polyacrylic acid, an alkali metal salt thereof or an ammonium salt thereof coexists. Provided is a capacitor added to a conductive polymer layer.

More specifically, water is preferably used as a solvent for the monomer solution, and the thickening action of polyacrylic acid or its alkali metal or ammonium salt causes the capacitor element to be immersed in the polymerizable monomer solution and then oxidized. When a conductive polymer layer is formed by immersion in an oxidizing agent solution to cause a chemical oxidative polymerization reaction, diffusion of monomer molecules in the oxidizing agent solution is suppressed, so that efficient and easy dielectric A conductive polymer layer can be formed on the body surface.

In this case, by setting the concentration of polyacrylic acid or its alkali metal or ammonium salt as an insulator to be 0.1 wt% or more and 0.3 wt% or less,
A decrease in the electrical conductivity of the formed conductive polymer layer can be substantially eliminated, so that it is possible to avoid adverse effects on the capacitor characteristics.

Here, the polymerizable monomer in the polymerizable monomer solution is preferably at least one selected from the group consisting of pyrrole, thiophene, aniline and derivatives thereof.

As described in claim 17, the oxidizing agent solution preferably contains a compound containing a transition metal ion, or persulfuric acid or a salt thereof.

More specifically, iron (III), copper (II), molybdenum (VI), chromium (VII), manganese (VII) and the like can be used as the transition metal ion. For example, lithium salts, sodium salts, potassium salts, ammonium salts and the like can be used.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. (Embodiment 1) FIG. 1 is a sectional view of a capacitor according to the present embodiment.

In FIG. 1, reference numeral 11 denotes an anode lead,
Reference numeral 12 denotes an anode valve metal serving as an anode of the capacitor, which is made of, for example, tantalum or aluminum.

[0044] Also, 13 is a dielectric coating as a dielectric layer of the capacitor, in response to an anode valve metal 12, Ta ₂ O ₅
Alternatively, it is composed of Al ₂ O ₃ .

Reference numeral 14 denotes polymer fine particles. The polymer fine particles 14 are, for example, pyro-polymers obtained by chemical oxidative polymerization using a polymerizable monomer solution and an oxidizing agent solution.
Conductive polymer containing thiophene, aniline or a derivative thereof as a repeating unit, having an average particle size of 0.5 μm
Crushed into polymer fine particles.

Reference numeral 15 denotes a conductive polymer layer obtained by chemical oxidation polymerization, for example, pyrrole, thiophene,
It contains aniline or a derivative thereof as a repeating unit.

Reference numeral 16 denotes a carbon paint film, reference numeral 17 denotes a silver paint film serving as a cathode of a capacitor, and reference numeral 18 denotes a cathode lead. Here, the carbon paint film 16 is for improving the adhesion between the conductive polymer layer 15 and the silver paint film 17.

Of course, the above configuration is a typical example, and it is possible to use another material or manufacturing method that can realize the same function.

Hereinafter, the structure and manufacturing method of such a capacitor will be described more specifically with reference to FIG.

First, an anode valve metal 12 (size (mm): a rectangular parallelepiped tantalum sintered body with an anode lead 11 attached thereto:
Length 3, Height 3.8, Width 1.4, CV product 30,000μFV /
g) was anodized with a 0.5% aqueous phosphoric acid solution at about 90 ° C. for 60 minutes at an applied voltage of 42 V to form a dielectric film 13.

This device was prepared by mixing polypyrrole fine particles (5% by weight) having an average particle diameter of 0.5 μm and a pyrrole monomer (1 m
ol / l) for 7 minutes, followed by 15 minutes in an oxidizing aqueous solution containing 0.222 mol / l of ferric sulfate hydrate to perform chemical oxidative polymerization. And drying at 105 ° C. for 5 minutes.

By repeating this operation 12 times, the polypyrrole fine particles 14 are formed inside and on the surface of the anode valve metal 12.
The conductive polymer layer 15 of polypyrrole containing was formed.

Here, the polypyrrole fine particles used had the same composition as that used when the polypyrrole layer of the conductive polymer layer 15 was formed, and were prepared at 25 ° C. using a polymerization solution.
It is produced by polymerizing for an hour and then pulverized.

Next, a carbon paint film 16 and subsequently a silver paint film 17 are formed by an ordinary method.
7 is provided with a cathode lead 18 and aging is performed with an applied voltage of 1
The operation was carried out at 3 V, and a total of 10 solid electrolytic capacitors were obtained by covering with a resin.

The average capacitance, loss coefficient, impedance, withstand voltage, and film thickness 19 of the thinnest portion of the polypyrrole layer of the obtained capacitor are shown in Table 1 below.

[0056]

[Table 1]

Comparative Example 1 In this comparative example, ten solid electrolytic capacitors were produced in the same manner as in Embodiment 1 except that no polypyrrole fine particles were contained.

The capacity, loss coefficient, impedance, withstand voltage and film thickness of the polypyrrole layer of this capacitor are shown in Table 1 above.

From the comparison between Embodiment 1 and Comparative Example 1 shown in Table 1, by adding polypyrrole fine particles, a polypyrrole layer about twice as thick was formed at the same number of polymerization repetitions. It can be seen that the withstand voltage has been improved.

That is, it can be understood that the effect of effectively increasing the thickness of the conductive polymer layer clearly improves the withstand voltage.

When a capacitor having a polypyrrole layer formed in the same manner as in Embodiment 1 except that a pyrrole monomer solution containing no polypyrrole fine particles was used, the film thickness was approximately the same as that in Embodiment 1. The number of polymerization repetitions required to form a polypyrrole layer was 48. From this, the effect of reducing the number of times of polymerization repeated required for forming a polypyrrole layer having a desired thickness by using a polymerization solution to which conductive polymer fine particles are added is also apparent.

(Embodiment 2) In this embodiment, 10 solid electrolytic cells are used in the same manner as in Embodiment 1 except that polypyrrole fine particles having an average particle diameter of 1 μm (A) and 3 μm (B) are used. Complete the capacitor, Embodiment 1
The same evaluation was performed.

The results are shown in the above (Table 1). In Table 1, when fine particles having an average particle size of 1 μm were used,
The same result as in the case of 0.5 μm was obtained. In the case of the fine particles of 3 μm, the withstand voltage was the same as that of the first embodiment. However, since the coating thickness of polypyrrole was excessively large, the loss coefficient was large. And degradation of impedance was observed.

Here, when examined in more detail, from the comparison between Embodiment 1 and Comparative Example 1, in order to improve the withstand voltage, the thickness of the polypyrrole layer needs to be a certain value or more. Further, when compared with Embodiment 2, if the balance between the loss coefficient and the impedance is also considered,
It is considered that there is an optimum range of the thickness of the polypyrrole layer that is equal to or less than a certain value.

Then, the thickness of the polypyrrole layer was changed by variously changing the average particle diameter of the added polypyrrole fine particles, and the withstand voltage, loss coefficient and impedance were measured in the same manner as in the first embodiment. It was concluded that the film thickness was preferably from 10 μm to 20 μm. Here, the average particle diameter of the added polypyrrole fine particles corresponding to this film thickness is 0.3 μm or more and 1 μm.
m or less.

(Embodiment 3) In the present embodiment, instead of polypyrrole fine particles, the particles obtained by chemical oxidation polymerization were used.
Ten solid electrolytic capacitors were produced in the same manner as in Embodiment 1 except that poly (3,4-ethylenedioxythiophene) (A) and polyaniline (B) each having an average particle diameter of 1 μm were used. The same evaluation as in Embodiment 1 was performed.

The results are shown in the above (Table 1). From Table 1, it can be understood that a thick polypyrrole layer was formed and the withstand voltage was improved irrespective of the type of the conductive polymer fine particles added.

Also in this embodiment, the withstand voltage, loss coefficient and impedance were measured in the same manner as in the first embodiment by changing the average particle size of the added polythiophene and the like in various ways to change the thickness of the polypyrrole layer. As a result, it was concluded that the thickness of the polypyrrole layer was preferably from 10 μm to 20 μm. Here, the average particle diameter of the added fine particles corresponding to this film thickness is 0.3 μm or more and 1 μm or more.
μm or less.

(Embodiment 4) In the present embodiment, 10 electrodes are used under the same conditions as in Embodiment 1 except that the following etched aluminum foil electrode is used in place of the tantalum sintered body of Embodiment 1. Was completed, and the same characteristics were evaluated. The results are shown in the above (Table 1).

The specific method of manufacturing the aluminum electrode foil is as follows. First, a polyimide tape 7 having a width of 1 mm is stuck on both sides so as to partition a 4 × 10 mm aluminum etched foil into portions of 3 mm and 6 mm.

Next, the 4 × 3 aluminum etched foil 1
The anode lead of 4 mm was attached, and a 4 × 6 mm portion of the aluminum-etched foil was subjected to anodic oxidation using a 3% aqueous solution of ammonium adipate at about 70 ° C. to form an oxide film dielectric layer.

Here, this configuration is regarded as a capacitor,
When the volume in the chemical conversion solution was measured, it was 4.7 μF.

(Comparative Example 2) In this comparative example, 10 parts were prepared in the same manner as in Embodiment 4 except that no polypyrrole fine particles were contained.
Each solid electrolytic capacitor was manufactured.

The capacity, loss coefficient, impedance, withstand voltage and film thickness of the polypyrrole layer of this capacitor are shown in Table 1 above.

Embodiment 4 and Comparative Example 2 in (Table 1)
From the comparison with, even when using aluminum electrode foil,
It is clear that by adding the polypyrrole fine particles, a thick polypyrrole layer was formed at the same number of polymerization repetitions, and the withstand voltage was improved reflecting the formation.

Further, even when an aluminum electrode foil is used, the average particle size of polythiophene or the like to be added is changed variously to change the thickness of the polypyrrole layer.
When the withstand voltage, the loss coefficient and the impedance were measured in the same manner as described above, the thickness of the polypyrrole layer was 10 μm or more and
It has been concluded that it is preferable that the diameter is not more than μm. Again, the average particle size of the added fine particles corresponding to this film thickness was 0.3 μm or more and 1 μm or less.

(Embodiment 5) In the present embodiment, instead of forming an oxide film dielectric in the structure of Embodiment 4, after applying polyamic acid by electrodeposition, about 2
A total of 10 capacitors were manufactured under substantially the same conditions as in Embodiment 4 except that an electrode formed by heating and curing at 50 ° C. and having a polyimide dielectric layer formed of a polyimide thin film having a thickness of 0.1 μm was used. did.

These were evaluated in the same manner as in the fourth embodiment, and the results are shown in the above (Table 1).

(Comparative Example 3) In this comparative example, except that no polypyrrole fine particles were contained, the same procedure as in Embodiment 5 was repeated.
Each capacitor was manufactured.

The capacity, loss coefficient, impedance, withstand voltage and film thickness of the polypyrrole layer of this capacitor are shown in Table 1 above.

From the comparison with Embodiment 5 in Table 1, by adding the polypyrrole fine particles, a thick polypyrrole layer was formed with the same number of polymerization repetitions.
It is clear that the withstand voltage has been improved to reflect this.

Also in the film capacitor using polyimide as the dielectric as described above, the average particle size of the polypyrrole to be added is changed variously to change the film thickness of the polypyrrole layer. , Loss coefficient and impedance were measured, and it was concluded that the thickness of the polypyrrole layer was preferably from 10 μm to 20 μm. Again, the average particle size of the added fine particles corresponding to this film thickness was 0.3 μm or more and 1 μm or less.

The capacitor manufactured here does not show the polarity seen in the electrolytic capacitor, and can be used as a non-polar capacitor.

Further, here, only one electrode is formed of a conductive polymer layer, but a conductive polymer layer can also be used for the other electrode.

(Embodiment 6) In this embodiment, polypyrrole fine particles (5 wt%) were added to a solution containing 3,4-ethylenedioxythiophene: ethanol: n-butyl alcohol = 1: 2: 2 (weight ratio). %) And an n-butanol oxidizing agent solution containing 50% of ferric p-toluenesulfonate was prepared in the same manner as in Embodiment 1 except that a monomer solution containing 50% of ferric p-toluenesulfonate was prepared. The same evaluation as in Example 1 was performed.

The number of polymerization repetitions required to form a 10 μm-thick poly (3,4-ethylenedioxythiophene) was 11 times.

The results are shown in the above (Table 1). (Comparative Example 4) In this comparative example, ten capacitors were produced in the same manner as in Embodiment 6 except that polypyrrole fine particles were not included.

The capacity, loss coefficient, impedance, withstand voltage and film thickness of the polythiophene layer of this capacitor are shown in the above-mentioned (Table 1).

Embodiment 6 and Comparative Example 4 in Table 1
From the comparison with the above, it is clear that by adding the polypyrrole fine particles, a thick polythiophene layer is formed at the same number of polymerization repetitions, and the withstand voltage is improved reflecting the formation.

In the system without adding the polypyrrole fine particles, the number of times of polymerization required for forming a 10 μm-thick polythiophene layer was 45 times. It is also evident that the number of polymerizations required for can be greatly reduced.

Even when the conductive polymer layer is made of polythiophene, the average particle size of the polypyrrole to be added is changed variously to change the thickness of the polythiophene layer. When the voltage, the loss coefficient, and the impedance were measured, it was concluded that the thickness of the polythiophene layer was preferably 10 μm or more and 20 μm or less. Again, the average particle size of the added fine particles corresponding to this film thickness was 0.3 μm or more and 1 μm or less.

(Embodiment 7) In this embodiment, in Embodiment 1, an aniline monomer is used instead of a pyrrole monomer, and ammonium persulfate is replaced with 0.4 mol / l instead of ferric sulfate. Ten solid electrolytic capacitors were completed in the same manner as in Embodiment 1 except that acetone was used as the poor solvent, and the same evaluation as in Embodiment 1 was performed. The results were shown in Table 1 above. Indicated.

The number of times of polymerization required for forming a 10 μm-thick polyaniline layer was 18 times.

Comparative Example 5 For comparison, ten capacitors were produced in the same manner as in Embodiment 7 except that polypyrrole fine particles were not included.

The capacitance, loss coefficient, impedance, withstand voltage and film thickness of the polyaniline layer of this capacitor are shown in Table 1 above.

Embodiment 6 and Comparative Example 5 in Table 1
It is clear from the comparison with that that by adding the polypyrrole fine particles, a thick polyaniline layer was formed at the same number of polymerization repetitions, and the withstand voltage was improved reflecting this.

In the system without adding polypyrrole fine particles, the number of times of polymerization required for forming a 10 μm-thick polyaniline layer is 125 times. In the case of polyaniline, the film thickness is particularly difficult to grow, Thus, it is apparent that the number of polymerizations required for forming a film thickness necessary for improving the withstand voltage can be significantly reduced.

Even when the conductive polymer layer is made of polyaniline, the average particle size of the polypyrrole to be added is changed variously to change the thickness of the polyaniline layer. When the voltage, loss coefficient and impedance were measured, the thickness of the polyaniline layer was
It has been concluded that it is preferable that the thickness be 10 μm or more and 20 μm or less. Again, the average particle size of the added fine particles corresponding to this film thickness was 0.3 μm or more and 1 μm or less.

(Embodiment 8) In this embodiment, instead of adding the polypyrrole fine particles to the monomer solution in Embodiment 1, 0.1% by weight of a cross-linked polyacrylic acid salt (manufactured by Wako Pure Chemical Industries, Ltd .: Hibiswaco) is used. % Except that
Ten solid electrolytic capacitors were completed in the same manner as in the first embodiment, and the same evaluation as in the first embodiment was performed. The results are shown in Table 1 above.

The number of times of polymerization required for forming a 10 μm-thick polypyrrole layer was 12 times.

(Embodiment 9) In this embodiment, ten capacitors were manufactured in the same manner as in Embodiment 8, except that the concentration of the crosslinked polyacrylate was changed to 0.3%. The same evaluation as in the first embodiment was performed, and the results are shown in the above (Table 1).

Comparative Example 6 For comparison, ten capacitors were manufactured in the same manner as in Embodiment 8 except that the concentration of the cross-linked polyacrylate was changed to 0.5%. The same evaluation as in Example 1 was performed, and the results were compared with those in Table 1 above.
It was shown to.

In Table 1, when compared with Embodiments 8, 9 and Comparative Example 6, first, by adding a cross-linkable polyacrylate, the formation of a polyporol layer having a large film thickness is reduced and polymerization is repeated. It was clarified that a capacitor with high withstand voltage can be obtained by reflecting the change.

Further, when the cross-linked polyacrylate is 0.3
%, A capacitor having a high withstand voltage equivalent to that of 0.1% in both loss coefficient and impedance can be obtained. However, in the case of 0.5%, deterioration of the loss coefficient and impedance is observed. .

That is, also in this case, in order to improve the withstand voltage, the thickness of the polypyrrole layer needs to be a certain value or more. Further, when compared with the second embodiment, the loss coefficient and the impedance From the viewpoint of balance, it is considered that there is an optimum range of the film thickness of the polypyrrole layer which is equal to or less than a certain value.

Therefore, when the concentration of the added cross-linked polyacrylate was changed variously to change the thickness of the polypyrrole layer and the withstand voltage, loss coefficient and impedance were measured in the same manner as in Embodiment 1, polypyrrole was measured. It was concluded that the thickness of the layer is preferably from 10 μm to 20 μm. Here, the concentration of the added cross-linked polyacrylate corresponding to this film thickness is 0.1 wt% or more and 0.3 wt% or less.
Since it is essentially an insulator, exceeding this range is considered to cause further deterioration of the loss coefficient and the impedance in the layer in which it is compounded.

In the first, second, fourth and fifth embodiments,
In the above, the conductive polymer particles to be added and the conductive polymer layer polymerized and formed in situ are described in the case of polypyrrole obtained from the same composition or obtained.Of course, those obtained from other compositions are used. It may be used, and furthermore, polythiophene, polyaniline, or the like may be used.

In the third, sixth and seventh embodiments, the specific case where the fine particles of the conductive polymer and the conductive polymer layer are different from each other has been described. However, if the combination of polypyrrole, polythiophene and polyaniline is used. I don't care.

Further, in the above-described first to seventh embodiments, the case where the fine particles of the conductive polymer to be added are dispersed in the monomer solution has been described. However, the fine particles may be dispersed in the oxidizing agent solution or divided into two. The same effect can be obtained by adding and dispersing.

Further, in Embodiments 8 and 9 described above, a cross-linked polyacrylic acid salt has been described. However, a polymerizable monomer solution in which polyacrylic acid, an alkali metal salt thereof, or an ammonium salt thereof coexists is used. A similar result can be obtained.

[0111]

As described above, the present invention is particularly applicable to a capacitor in which a conductive polymer layer obtained by in situ chemical oxidative polymerization of a polymerizable monomer is used as an electrolyte or an electrode. By adding the conductive polymer fine particles or polyacrylic acid or a salt thereof obtained by the above to the polymerization solution, it is possible to easily form a conductive polymer layer having a film thickness of 10 μm or more. Thus, it is possible to realize a capacitor having a high potential and an excellent high-frequency characteristic.

[Brief description of the drawings]

FIG. 1 is a structural sectional view of a capacitor according to a first embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Anode lead 12 Anode valve metal 13 Dielectric film 14 Polymer fine particles 15 Conductive polymer layer 16 Carbon paint film 17 Silver paint film 18 Cathode lead 19 Thickness of thinnest part of solid electrolyte

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Yasuo Kudo 3-10-1 Higashi-Mita, Tama-ku, Kawasaki City, Kanagawa Prefecture Matsushita Giken Co., Ltd.

Claims (17)

[Claims] 1. A conductive polymer, comprising: a pair of electrodes provided to face each other; and a dielectric layer provided between the electrodes, wherein at least one of the electrodes is obtained by polymerizing a polymerizable monomer. A capacitor having a layer, wherein the thickness of the conductive polymer layer is increased by adding conductive polymer fine particles or cross-linked polyacrylic acid or a salt thereof before polymerization. 2. The capacitor according to claim 1, wherein the thickness of the conductive polymer layer is 10 μm or more. 3. The capacitor according to claim 1, wherein the conductive polymer of the conductive polymer layer is polypyrrole, polythiophene, or polyaniline. 4. The capacitor according to claim 1, wherein the conductive polymer of the conductive polymer fine particles is polypyrrole, polythiophene, or polyaniline. 5. The capacitor according to claim 3, wherein the conductive polymer of the conductive polymer layer and the conductive polymer of the conductive polymer fine particles are of the same type. 6. The capacitor according to claim 1, wherein the dielectric layer is an oxide film of a valve metal. 7. The capacitor according to claim 6, wherein the valve metal is tantalum or aluminum. 8. The capacitor according to claim 1, wherein the dielectric layer is a polymer layer. 9. The capacitor according to claim 8, wherein the polymer of the polymer layer is polyimide. 10. The method according to claim 1, further comprising: arranging a pair of electrodes facing each other, arranging a dielectric film between the electrodes, and forming a conductive polymer layer on at least one of the electrodes. The method for producing a capacitor, wherein the step of forming the conductive polymer layer includes a step of adding conductive polymer fine particles or cross-linked polyacrylic acid or a salt thereof. 11. The method for manufacturing a capacitor according to claim 10, wherein the step of forming the conductive polymer is a chemical oxidative polymerization step using a polymerizable monomer solution and an oxidizing agent solution. 12. The method according to claim 10, wherein the conductive polymer fine particles are contained in at least one of a polymerizable monomer solution and an oxidizing agent solution. 13. The method for manufacturing a capacitor according to claim 12, further comprising a step of preparing conductive polymer fine particles by polymerizing a polymerizable monomer. 14. The method according to claim 13, wherein the polymerizable monomer is at least one selected from pyrrole, thiophene, aniline and derivatives thereof. 15. The method for producing a capacitor according to claim 11, wherein a polymerizable monomer solution in which polyacrylic acid, an alkali metal salt thereof, or an ammonium salt thereof coexists. 16. The method for producing a capacitor according to claim 11, wherein the polymerizable monomer in the polymerizable monomer solution is at least one selected from pyrrole, thiophene, aniline, and derivatives thereof. 17. The oxidizing agent solution contains a compound containing a transition metal ion, or persulfuric acid or a salt thereof.
17. The method for manufacturing a capacitor according to any one of items 1 to 16.