JPS6116684Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a composite capacitor, and particularly to a solid electrolytic capacitor with improved impedance characteristics.

For example, in a conventional solid electrolytic capacitor, as shown in Fig. 1, a capacitor element 1 is made by press-molding metal powder having a valve action such as tantalum, niobium, or aluminum into a cylindrical shape or the like, and a valve action is applied in advance to the capacitor element 1. The metal wire is buried as the anode lead B, and is then led out by welding or the like. Next, the capacitor element is sintered in a high vacuum at a temperature of around 2000°C, and then a dielectric layer of an oxide film is formed on the porous surface by anodizing using a phosphoric acid aqueous bath. Next, apply manganese salt such as manganese nitrate to the surface at a temperature of 250.
It is thermally decomposed in a constant temperature furnace at around ℃ to form a manganese dioxide layer. Next, it is immersed in a graphite solution at room temperature and fired at a temperature of around 200°C, and then a silver paste consisting mainly of silver fine particles is applied by immersion. Furthermore, the cathode lead is pulled out by immersing it in molten solder or the like.

However, with such conventional means, (a) since the solid electrolytic capacitor element is a porous material, the equivalent series resistance from the surface of the dielectric layer to the solder layer becomes large, and the impedance value does not depend on the frequency, that is, the impedance value at the resonant frequency. is 0.5Ω~
The value is 1Ω. For this reason frequency 1MHz ~ 10M
The response in the Hz band deteriorated, and the logic circuit was unable to completely absorb power supply noise, causing malfunctions.

(b) 0.1 as an improvement measure for the solid electrolytic capacitor in (a)
Measures have been taken to mount a ceramic capacitor with a capacitance on the order of .mu.F in parallel with a solid electrolytic capacitor, but such conventional means have the disadvantage of increasing the number of steps during mounting and increasing the mounting area.

(c) In many of the solid electrolytic capacitors mentioned above, a metal wire such as nickel that can be joined to the lead wire planted on the capacitor element A is welded, and the cathode lead wire 6 is taken out from the solder surface in the same direction, and then the resin case is The exterior of the capacitor element A is either inserted into the capacitor element A and injected with a resin such as epoxy, or covered around the capacitor element A with a resin dip or the like. However, with this conventional means, it is difficult to maintain a constant distance between the positive and negative lead wires, and a large number of man-hours are required when mounting on a printed circuit board or the like.

As an improvement over these conventional means, a method of fixing the terminal board 3 by passing it through a lead wire is often taken, but this does not improve the impedance characteristics.

It is an object of the present invention to provide a capacitor that overcomes the drawbacks of the prior art.

According to the present invention, an electrode lead layer is formed around a metal anode body having a valve action through an oxide film layer and a semiconductor layer, and a valve metal wire of the same type is led out to a capacitor element connected to a cathode lead wire. A multilayer chip type ceramic capacitor element is connected as a second capacitor between the first capacitor element and the anode and cathode lead wires of the first capacitor, and
A composite capacitor is obtained in which the lead wires of the capacitor are maintained at a constant distance and are covered with a resin plate.

Embodiments of the present invention will be described below with reference to FIGS. 2a, b, 3 a, b, 4 a, b, and 5.

Reference numeral 1 in the figure is the first capacitor, and a tantalum solid electrolytic capacitor with a rating of 36V1μF is used. The first capacitor 1 is made of tantalum powder of approximately 5000CV (capacitance (μF) x anodizing voltage)/gr and has a width of 4mm.
×Molded to 1mm thick × 1.8mm high, with 0.3 mm in the center
A tantalum anode lead wire 4 of φ was implanted, and the element was sintered for 30 minutes in a high-temperature vacuum furnace at a temperature of 1900°C, and each layer of oxide film, manganese dioxide, graphite, silver paste, and solder was sequentially applied using known methods. Form in layers. Figure 6A shows the impedance characteristics of this element when a soldered nickel wire is attached.

Next, code 2 is based on barium titanate.
A second capacitor was formed with a low equivalent series resistance multilayer chip ceramic capacitor rated at 50 V and 0.1 μF, with a distance between lead wires of 5 mm, a width of 5 mm, and a thickness of 1.5 mm. The impedance characteristics of this second capacitor element 2 are shown in FIG. 6B.

Next, a second capacitor 2 (FIGS. 2 to 4
(see figure) with solder 7, and
The impedance characteristic after the resin plate 8 is applied inside is shown in FIG. 6c.

As mentioned above, the composite capacitor according to the present invention has a frequency of 1M.
A composite capacitor that can significantly improve the impedance of a tantalum solid electrolytic capacitor from Hz to 10 MHz, and also allows a ceramic capacitor to fit within the external dimensions of a conventional solid electrolytic capacitor, has a great effect.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an example of a conventional solid electrolytic capacitor, FIGS. A top view and a side view, FIG. 5 is a sectional view showing one embodiment of the composite capacitor of the present invention, and FIG. 6 is an impedance characteristic diagram, in which both the vertical and horizontal axes are logarithmic axes. DESCRIPTION OF SYMBOLS 1... First capacitor element, 2... Second capacitor element, 3... Terminal plate, 4... Anode lead wire, 5... Anode lead wire, 6... Cathode lead wire, 7... Solder , 8...resin, 9...exterior case.

Claims (1)

[Scope of utility model registration request] A first capacitor element and a second capacitor element are housed in the same container, and a pair of lead wires of the first capacitor element are connected to electrodes of the second capacitor element and drawn out. In the composite capacitor, the first capacitor element is a solid electrolytic capacitor, and the second capacitor element is a multilayer chip-type ceramic capacitor having a notch or hole that maintains a constant distance between the pair of lead wires. Composite capacitor with special features.