JPS6314458Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a thin rectangular tantalum capacitor pellet.

In order to meet the trend toward thinner electronic devices, the electronic components used in the circuits are also required to be thinner. In order to make capacitors thinner,
Ceramic capacitors and tantalum solid electrolytic capacitors are so-called chip-type capacitors in which lead terminals are not drawn out. Among these, ceramic capacitors are used in the field of small capacitances of 0.1 μF or less, and tantalum capacitors are used for capacitances of 0.1 μF or more. Tantalum capacitors are made by press-forming high-purity fine tantalum powder with embedded tantalum wire, then sintering it in a vacuum atmosphere to create a porous sintered body, which is then coated with an oxide film. Furthermore, a tantalum solid electrolytic capacitor is manufactured by covering the capacitor with manganese dioxide, coating it with colloidal carbon and silver paste, and connecting the cathode terminal.

In conventional tantalum pellets, when molding tantalum wire 1 and tantalum powder 2, in order to maintain mechanical strength, when forming pellets 3 in a cylindrical shape, the tantalum wire 1 is formed into a cylindrical shape, as shown in Fig. 1. In the case of a rectangular pellet 4 disposed at the center, the tantalum wire 1 was formed so as to be covered with tantalum powder 2 while maintaining a certain thickness.

The tantalum capacitor pellets of the present invention are molded to a thickness that is approximately the same as or less than the thickness of the tantalum wire in order to make the molded product as thin as possible.

The embodiments of the present invention will be explained based on the drawings: 1
0 is a tantalum capacitor pellet, and tantalum powder is formed into a rectangular shape 11. The diameter D of the tantalum wire 12 is the same as or slightly larger than the thickness T of the molded body 11, and when molded, the thickness T of the molded body 11 is
becomes the same as As shown in FIG. 3, the tantalum wire 12 is exposed 12A on the surface of the molded body 11. It is characterized in that it is not completely buried in the powder 2 like the conventional tantalum wire 1. Such tantalum pellets 10 generally have low mechanical strength and are difficult to work with in subsequent steps. The present inventor discovered that a capacitor that is comparable to conventional capacitors can be obtained if the conditions described below are satisfied.

The relationship between the molded body 11 formed from the powder of the present invention and the tantalum wire 12 will be explained using the cross-sectional view of FIG. 4. The buried length A of the tantalum wire 12 is 1/4 It is necessary that it is within the range of <A3/4B and that C>3D for the width C of the molded body.

By making the capacitor pellets with the above-mentioned structure, the present invention has made it possible to use tantalum solid electrolytic capacitors instead of ceramic capacitors as thin capacitors. It is now possible to increase the capacitance of several tens of μF, which was previously difficult, and this will greatly contribute to making electronic devices thinner.

[Brief explanation of the drawing]

Figure 1 is a perspective view of a conventional cylindrical pellet, Figure 2 is a perspective view of a conventional cylindrical pellet;
The figure is a perspective view of a square pellet, FIG. 3 is a perspective view of the square pellet of the present invention, FIG. 4 is a sectional view, and FIG. 5 is a side view. In the drawing, 10 is tantalum pellets, 11
1 is a molded body, and 12 is a tantalum wire.

Claims (1)

[Scope of utility model registration request] In tantalum solid electrolytic capacitor pellets, which are made by vacuum sintering a compact made by embedding tantalum wire and molding tantalum powder into a rectangular shape, the diameter of the tantalum wire is equal to or slightly larger than the thickness of the compact, and the length of the compact is In contrast, the buried length of tantalum wire is 1/4 or more and 3/4
A rectangular tantalum capacitor pellet, characterized in that the width of the formed body is at least three times the diameter of the tantalum wire.