JPH0763045B2 - Capacitor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a capacitor having a polymer material layer as a dielectric and having a high capacity and good frequency characteristics.

[Conventional technology]

A conventional film capacitor is formed by vapor-depositing a metal such as aluminum on an ultra-thin film and then winding it in multiple layers.

On the other hand, the conventional electrolytic capacitor has a foil, rod,
An oxide film provided on the surface of a sintered body or the like is formed as a dielectric.

[Problems to be solved by the invention]

In the case of the above-mentioned film capacitor, it is extremely difficult to manufacture a film having a thickness of 2 μm or less at a low price due to the problem of the strength of the ultra-thin film. Becomes

On the other hand, electrolytic capacitors, when using a liquid electrolyte,
The high frequency characteristics are worse than the film capacitor, and when a solid electrolyte is used, the withstand voltage is worse than the film capacitor. In addition, electrolytic capacitors have the disadvantage that they are not suitable for certain applications due to their polarity.

[Means for solving problems]

The present inventor, as a result of diligent research to solve such problems, as a result, a metal foil, a metal rod, a metal sintered body or the like having pores or voids created for the purpose of increasing the surface area is formed on the surface. A polymeric material is formed as a dielectric layer along with a semiconductor layer containing lead dioxide on the dielectric layer to provide high capacity, good high frequency performance, high breakdown voltage, and inexpensive non-polar capacitor. As a result, they have found that they can be manufactured and have completed the present invention.

The metal used in the present invention may be any metal as long as it can form a foil, a rod, a sintered body or the like. It may also be an alloy. Examples thereof include aluminum, iron, nickel, tantalum, copper, niobium, tin, zinc and lead, but it goes without saying that they are not necessarily limited to these.

The method of forming pores or voids in such a metal for the purpose of increasing the surface area is as follows.
For example, by etching, in the case of sintered metal,
It can be produced by sintering itself. The size of pores, the depth, and the volume of voids can be changed by the etching method, sintering pressure, temperature, etc.
A polymer material layer described later is introduced along such pores or voids.

As an etching method, for example, in the case of aluminum, an electrolytic etching method of applying a direct current or an alternating current may be used.

The polymer substance used in the present invention may be any as long as it has a performance as a dielectric, and examples thereof include fluororesin, alkyd resin, acrylic resin, ester resin such as polyethylene terephthalate, and vinyl resin. Examples thereof include, but are not limited to, xylylene resin and phenol resin.

Examples of the method for introducing such a polymer substance into the above-described metal pores or spaces include, for example, a method of introducing a monomer in a gaseous state or a liquid state and polymerizing it, or a method of dissolving the polymer substance in an appropriate solvent and introducing it. And a method of melting and introducing the polymer substance itself. The polymeric material described above adheres to the surface of the metal and acts as a dielectric layer. In this case, it is necessary to consider the introduction method or the diameter of the pores so that the polymer substance does not block the pores or voids of the metal, and the conditions and the like are determined by preliminary experiments.

In the present invention, the lead dioxide-containing semiconductor layer formed on the polymer layer is preferably a lead dioxide layer or a semiconductor layer containing lead dioxide and lead sulfate as main components. Examples of the method of introducing the semiconductor layer onto the polymer material layer having pores or voids include a method of melting and introducing the semiconductor, a method of producing the semiconductor on the polymer material layer, and the like. this house,
A method of producing a semiconductor on a polymer material layer is preferable, and a method of producing a semiconductor proposed by the present inventors in Japanese Patent Application No. 60-193185 by a chemical deposition method is particularly preferable.

Further, a conductor layer may be provided on the semiconductor layer to improve electrical contact with the lead wire. As the conductor layer, for example, solidification of the conductive paste, plating, metal deposition,
It can be formed by forming a heat-resistant conductive resin film or the like. As the conductive paste, silver paste, copper paste, aluminum paste, carbon paste, nickel paste and the like are preferable, but these may be used alone or in combination of two or more. If two or more are used, they may be mixed or stacked as separate layers. After applying the conductive paste, leave it in the air or heat it to solidify. Examples of the plating include nickel plating, copper plating, silver plating, aluminum plating and the like. Further, examples of the vapor deposition metal include aluminum, nickel, copper, silver and the like.

The capacitor of the present invention having the above-described configuration can be used as a capacitor product for various applications by, for example, a resin mold, a resin case, an outer case made of metal, a resin dipping, an outer case such as a laminated film.

The drawing shows a specific example of the capacitor of the present invention. In the drawing, reference numeral 1 is a metal foil such as aluminum that serves as one electrode. Pores 2 ... Are formed on the surface of the metal foil 1 by an etching method, and a polymer film 3 serving as a polymer dielectric layer is provided along the surface of the pores 2. Further, a semiconductor layer 4 serving as the other electrode is provided on the polymer film 3, and a conductor layer 5 is provided on the semiconductor layer 4. Then, the lead wires 6 and 7 are connected to the metal foil 1 and the conductor layer 5, respectively, and the whole are sealed with a synthetic resin 8 to form a capacitor product.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

(Example 1) Terminals are caulked and lead wires are connected, length 2 cm, width 1
Aluminum foil (thickness 90 μm) of cm was used as an anode, and the surface of the foil was electrochemically etched with direct current to a diameter of 2.
An aluminum foil having pores of 5 μm and a depth of 30 μm on the entire surface was obtained. Then, a resin solution obtained by adding 40 parts by weight of toluene to 60 parts by weight of a resol type phenol resin was applied to an aluminum foil and cured at 140 ° C. to form a polymer dielectric layer.
Subsequently, the aluminum foil on which the polymer dielectric was formed was immersed in a mixed solution of an aqueous solution of lead acetate trihydrate of 2 mol / mol and ammonium persulfate of 4 mol /, and reacted at 80 ° C. for 30 minutes. The lead dioxide semiconductor layer formed on the foil was thoroughly washed with water and then dried under reduced pressure at 100 ° C. Furthermore, after applying silver paste on this and taking out the terminal lead wire,
A resin was sealed to produce a capacitor.

(Example 2) Xylylene gas was introduced into an aluminum foil having the same pores as in Example 1 to carry out thermal polymerization. A semiconductor layer and a conductor layer were sequentially laminated on the resulting polymer dielectric in the same manner as in Example 1 to produce a capacitor.

Example 3 A solution prepared by dissolving 30 parts by weight of a copolymer of propylene hexafluoride and ethylene tetrafluoride was applied to an aluminum foil having the same pores as in Example 1 and dried under reduced pressure at 120 ° C. A semiconductor layer and a dielectric layer were laminated on the produced polymer dielectric in the same manner as in Example 1 to produce a capacitor.

(Example 4) The same operation as in Example 1 was performed on a sintered body of tantalum powder to manufacture a capacitor.

Comparative Example 1 Aluminum was vapor-deposited on an ultrathin film (10 μm thick) of polyvinylidene fluoride having a length of 18 cm and a width of 1 cm and folded into 9 sheets to obtain a metallized film capacitor. The bipolar terminals were taken out and then sealed with a resin.

Comparative Example 2 An aluminum foil similar to that in Example 1 was electrochemically treated in an aqueous solution of boric acid and ammonium borate to form an alumina dielectric layer. Further, an aluminum foil on which an alumina dielectric layer was not formed was used as a cathode, and a separator containing an ethylene glycol-ammonium adipate-based electrolytic solution was sandwiched to seal the resin, thereby producing an electrolytic capacitor.

For the various capacitors obtained in the examples and comparative examples, the capacitance, loss coefficient (tan δ), equivalent series resistance (ES
R), withstand voltage was measured. The results are shown in Table 1.

[Effects of the Invention] The capacitor of the present invention has the same volume as the metallized film capacitor, has a larger capacity and is less expensive, has a higher frequency performance than an electrolytic capacitor, has a higher breakdown voltage than a solid electrolytic capacitor, and has a polarity. High availability because it is not available.

[Brief description of drawings]

The drawing is a schematic sectional view showing a specific example of the capacitor of the present invention. 1 ... Metal foil, 3 ... Polymer film, 4 ... Semiconductor layer.

Claims (2)

[Claims] 1. A metal foil or a metal rod having pores on its surface is used as one electrode, a polymer substance layer provided in the pores is used as a dielectric, and lead dioxide provided on the polymer substance layer is included. A capacitor having a semiconductor layer as the other electrode. 2. A semiconductor layer containing lead dioxide, which is formed on one side of a sintered metal using a sintered metal as a dielectric, and a polymer material layer provided in a void in the sintered metal as a dielectric. A capacitor having the other electrode.