JPS6024199B2 - Current-carrying body for plating - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for applying live current to the conductive pattern when plating various metals on the surface of the conductive pattern formed on an insulating substrate such as a printed circuit board. The present invention relates to the structure of a current-carrying body for plating.

Conventionally, so-called printed circuit boards, which are made by forming various electrical circuits, fixed contacts for push-plow switches, and other conductive patterns on the surface of an insulating substrate, are designed to provide corrosion resistance to the conductive patterns or to facilitate soldering. They are plated with various metals such as nickel, gold, silver, palladium, and solder for purposes such as protection.

In this plating process, the printed circuit board is generally immersed in a plating bath, and the conductive pattern is used as a cathode to electrically connect the board to conduct electricity. Generally, the following three methods are used for this process. There is. That is, as shown in FIG. 1, the first method is to form a conductive pattern 2 on the surface of an insulating substrate 1 at the same time as a dedicated conductive pattern 3 for plating. This is a method in which electricity is applied through this dedicated energizing pattern 3 during processing, and after the plating process, the insulating substrate 1 is cut along the broken line C to remove the dedicated energizing pattern 3. As shown in FIG. 2, this is a method in which a conductive pattern 2 is formed on the surface of an insulating substrate 1, and then a lead wire 4 for plating is connected to the pattern to conduct electricity. As shown in FIG. 3, a current carrying body 5 made of a conductive elastomer or a metal plate is crimped onto the conductive pattern 2 in place of the IJ cord wire in FIG. 2, and current is passed through this current carrying body. . However, in the method of providing the first dedicated energizing pattern described above, a cutting process is added after the plating process, so this method cannot be applied at all to circuit boards with metal cores, and it also requires burrs during cutting. However, in the second method, the lead wires 4 for each conductive pattern may be damaged.
In addition to having to attach the lead wire 4, the lead wire 4 also has to be removed again after the plating process, which is troublesome.

On the other hand, in the method using the current-carrying body 5 made of the third metal plate conductive elastomer, electricity can be passed by simply crimping the conductor 5 onto the conductive pattern 2, which is an economical method suitable for mass production. However, since the conductive pattern 2 is normally formed slightly protruding from the surface of the substrate 1, the plating liquid tends to enter the crimping surface.
Furthermore, since the contact area of each conductive pattern with the conductor 5 varies, simply pressing the conductor 5 against the conductive pattern makes it difficult to obtain an even contact state with each conductive pattern, and in some cases may cause poor contact. As a result, there is a problem in that the flow to each conductive pattern becomes uneven, and non-uniform plating tends to occur. When the printed circuit board is strongly crimped, the printed circuit board may be cracked or deformed, and the conductive pattern 2 may be cut. The present invention relates to the structure of a new and improved conductor used in the third method described above, in which a concave portion is provided on one surface of a molded body made of a block-like or plate-like insulating elastomer. It is characterized in that a molded body made of a conductive elastomer having a hardness greater than that of the insulating elastomer is embedded and integrated in the recess.

The present invention will be explained in detail below based on FIGS. 4 to 1 of the accompanying drawings.

First, FIG. 4 shows a typical embodiment of the current-carrying body for plating according to the present invention, and FIG. plan view of the surface,
Figures b and c are cross-sectional views taken along line bb and c-c in figure a, respectively, and the conductor 10 consists of an insulating elastomer molded body 11 and a conductive elastomer embedded therein. A connecting electrode 13 is integrally bonded to the molded body 12 and electrically connected to the molded body 12.

The insulating elastomer molded body 11 according to the present invention is made of gastrointestinal rubber, various synthetic rubbers, or thermoplastic synthetic resin having flexibility and elasticity. It is made by dispersing various conductivity-imparting agents such as powder, metal powder, and metal-plated glass beads, and has a specific resistance of about 10-5 to 1 pi.

Further, the connection electrode 13 is constituted by a plate or foil made of a metal material that has low electrical resistance and excellent corrosion resistance. In the present invention, it is essential to provide a hardness difference between the insulating elastomer molded body 11 and the conductive elastomer molded body 12. When the printed circuit board is crimped to the surface and subjected to plating treatment by being energized in a plating chamber, the flexibility and elasticity of the insulating elastomer molded body 11 around the conductive elastomer molded body 12
The thickness of the conductive pattern formed slightly protruding from the surface of the printed circuit board is absorbed to prevent the plating liquid from entering the crimped surface between the conductor 10 and the substrate, especially the crimped surface of the conductive crab rubber molded body. In order to achieve this objective, the hardness of the insulating elastomer molded body 11 in the current carrying body 10 of the present invention is 20 to 7 of the rubber hardness specified in JIS.
On the other hand, the hardness of the conductive elastomer is 40o ~ 90o
o, and the difference in hardness between the two must be between 100 and 500.

Note that if there is no difference in hardness between the insulating elastomer molded body 11 and the conductive elastomer molded body 12 and the entire current-carrying body is relatively flexible, the current-carrying body may be crimped onto the printed circuit board surface. Even if it is possible to prevent the plating liquid from entering the crimped surface during the plating process, it is difficult to obtain a good electrical connection with the conductive pattern.On the other hand, when the entire current-carrying body is relatively hard, Even if a good electrical connection state is obtained between the conductive pattern and the conductive pattern, the function of preventing the plating liquid from entering the crimping surface (sealing function) is poor, and once the plating liquid does not enter the crimping surface of the conductive elastomer 12. If the plating is allowed, the plating is done on the crimped surface depending on the type of plating liquid, so the degree of freedom of the plating liquid is small, and it is difficult to obtain the desired performance for the conductive pattern, and furthermore, the plating layer may be defective. This results in various problems such as poor plating efficiency, poor plating efficiency, and deterioration of the plating solution.

Furthermore, the exposed surface (crimping surface) of the conductive elastomer molded body 2 in the current-carrying body 10' of the present invention does not need to be flush with the insulating elastomer molded body 11, as shown in FIGS. 1b and c. , as shown in FIG. 3D, may be slightly protruded, and in this case, the electrical connection to the conductive pattern on the printed circuit board can be improved. 5, 6, 7, 8, and 9 respectively illustrate plan views of the crimping surfaces in different embodiments of the current-carrying body for plating according to the present invention. As such, various shapes can be explored depending on the conductive pattern on the printed circuit board to which the current-carrying body of the present invention is to be attached.

Furthermore, FIG. 10 is a plan view showing a state in which, for example, the current-carrying body 10 as shown in FIG. 4 is crimped onto the printed circuit board 1 prior to the actual plating process.
FIG. 1 shows a state in which a current-carrying body 10 as shown in FIG. It is something that is administered. As explained above,
According to the current carrying body for plating of the present invention, when plating a conductive pattern on a printed circuit board, the current carrying body can be aligned with a predetermined position on the printed circuit board and simply crimped. By enabling electricity to flow and providing a hardness difference between the insulating elastomer molded body and the conductive elastomer molded body in this current-carrying body, a good electrical connection state of the conductive elastomer molded body to the conductive pattern is achieved. At the same time, it is possible to effectively prevent the plating liquid from entering the crimping surface between the conductor and the printed circuit board, particularly the crimping surface of the conductive elastomer molded body, so its practical value is extremely great.

[Brief explanation of drawings]

Figures 1 to 3 each illustrate a method of applying electricity when plating a conductive pattern on a printed circuit board according to the conventional method, and Figures 1 and 2 respectively The plan view and FIG. 3 are perspective views. FIG. 4 shows a typical embodiment of the current-carrying body according to the present invention, in which a is a plan view of its crimping surface, and b and c are views taken along the bb line and c-c line of a, respectively. Cross-sectional view d is a cross-sectional view showing another aspect of d. 5 to 9 each show the current-carrying body of the present invention, and are plan views of different embodiments. FIG. 10 and FIG. 11 are plan views showing different ways of using the current carrying body of the present invention. 1... Printed circuit board, 2... Conductive pattern, 3
... Dedicated current carrying pattern, 4... Current carrying lead wire, 5... Conductive elastomer or metal current carrying body, 10... Current carrying body of the present invention , 1 1
...Net-conforming elastomer molded body, 12...
... Conductive elastomer molded body, 13 ... Connection electrode. Figure 1 Figure 2 Figure 3 Blind drawing Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Books/Figure 1

Claims (1)

[Claims] 1. A recess is provided on one surface of a block- or plate-shaped molded product made of an insulating elastomer, and a molded product made of a conductive elastomer having a hardness greater than that of the insulating elastomer is embedded and integrated in the recessed part. Characteristics of the current-carrying body for plating.