JPS6317447B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrode pellet used for detecting electrical signals generated from a living body or measuring electrochemical properties.

Porous silver-silver chloride electrode pellets, which are made by compression molding a powder mixture of silver and silver chloride, are generally considered to have the best properties as electrodes for detecting low-level electrical signals from the skin surface of living organisms. .
FIG. 1 is a cross-sectional view showing the state in which this electrode pellet is used. An electrode pellet 1 made of a silver-silver chloride compression molded body has a specimen-facing surface 2 on one side. A lead wire 3 made of, for example, a copper wire or a silver-plated copper wire for deriving an electric signal to the other side is connected by a suitable connecting material 4, and the part other than the specimen facing surface 2 is connected to an electrically insulating resin 5. It is molded with. Then, an electrolytic solution is attached to the specimen-facing surface 2 of the electrode pellet 1,
It is attached to a specimen and captures the weak voltage of the living body.

Methods for connecting the lead wire to the electrode pellet include soldering with solder, brazing with metal solder, adhesion with conductive paste, and spot welding, among which spot welding is the most stable method. It has excellent properties and is widely used. For example, the conventional electrode pellet 1 made of a silver-silver chloride porous compression molded body shown in FIG. will occur. Furthermore, as the silver chloride composition of the pellet increases, it becomes more difficult to connect the lead wire, and a higher connection temperature is required to decompose the silver chloride and change the composition, making it difficult to obtain an electrode lead with stable characteristics. Furthermore, the electrolytic solution adhering to the specimen facing surface 2 penetrates into the electrode pellet of the porous body, reaches the connection part, and elutes the metal used as the connection material, making the electrode potential unstable during measurement and increasing accuracy. There is a major drawback that makes measurement impossible.

To compensate for these shortcomings, an electrode pellet has been proposed in which a silver plate 11 is compressed and bonded to one side of a silver-silver chloride porous compression molded body 1, and a lead wire is connected to this silver plate, as shown in Fig. 2B. has been done. in this case,
The silver plate 11 reinforces the mechanical strength, facilitates the connection of the lead wires, and acts as a barrier against electrolyte penetration, so the above-mentioned drawbacks are considerably improved, but silver-silver chloride porous compression molding The proportion of silver chloride in the body is 5%
If this value is exceeded, the bonding strength of the silver plate will be insufficient, and when a lead wire is connected to the silver plate by spot welding, heat will be generated due to the high electrical resistance of the silver-silver chloride porous compression molded body, and silver chloride will be generated. There are still problems that need to be solved, such as easy disassembly of the weld and difficulty in obtaining a clean welded appearance.

The present invention has been made in view of the above points.
The figure shows a cross-sectional view of the electrode pellet of the present invention. 1 is, for example, a silver-silver chloride porous compression molded body compression molded into a disk shape, which is inserted into a silver coating body 12 which is deep drawn to have a circular cross section, and then the silver coating body 1
Press molding is performed so that the bending allowance 12' of the end edge of 2 is bent inward. In this way, the silver-silver chloride porous compression molded body 1 is made of a coating made of silver which is rich in toughness and has good thermal conductivity and electrical conductivity. 12 and integrally molded. A lead wire is then spot welded to the silver coating 12.

With this structure, the mechanical strength of the electrode pellet of the present invention is greatly improved, and the bonding strength between the porous compression molded silver-silver chloride body and the silver coated body can also be sufficiently secured. Furthermore, the heat generated when connecting the lead wires is dissipated by silver, which has good heat dissipation properties, and the current circuit from the welding electrode is mainly formed in the outer silver layer with low electrical resistance, suppressing heat generation, which prevents the decomposition of silver chloride. This can be prevented and the composition can be stabilized.
Further, as in the conventional case, the silver layer serves as a barrier to infiltration of electrolyte.

As explained above, the electrode pellet of the present invention eliminates the drawbacks of the conventional electrode pellets, provides stable characteristics over a long period of time, and guarantees a long lifespan, and has great practical effects.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the state in which the electrode pellet is used, and FIGS. 2A and 2B are sectional views showing the structure of a conventional electrode pellet. FIG. 3 is a sectional view showing the structure of the electrode pellet of the present invention. DESCRIPTION OF SYMBOLS 1... Silver-silver chloride porous compression molded body, 2... Specimen facing surface, 3... Lead wire, 11... Silver plate, 12
...Silver coating, 12'...bending allowance.

Claims (1)

[Claims] 1 In an electrode pellet consisting of a silver-silver chloride porous compression molded body 1 having a specimen-facing surface 2 on one side,
It is characterized in that the outer periphery of the silver-silver chloride porous compression-molded body 1 is integrally molded with the specimen-facing surface 2 left intact and tightly surrounded by a coating 12 made of silver with good thermal conductivity and electrical conductivity. Electrode pellet.