JPS5834997A - Method of connecting both-side printed circuit board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in the electrical connection method of copper foil sections on both sides of a double-sided printed wiring board. The object of the present invention is to provide a method for electrically connecting parts.

Conventionally, in the connection method of this type of double-sided printed wiring board, copper foil portions are attached to both sides of the board 1, as shown in FIG.

There was a structure in which plating 3 was applied to the inner peripheral surface of the through hole to connect the copper foil parts on both sides. This method is suitable for industrial equipment that uses all high-quality materials for the substrate 1 and requires countless plating processes on one board, and has cost advantages, but it is suitable for use in consumer products such as television receivers, etc. The substrate materials used for this purpose (paper-based phenolic resin laminate, paper-based epoxy resin laminate, etc.) have the drawback that the plating 3 breaks due to expansion or contraction due to heat or the like of the substrate 1. Also, Metsuki 3
The processing cost was high and it was an economically unreasonable method.

On the other hand, as a conventional example for consumer equipment, as shown in FIG. 2, a grommet 6 made of yellow 3, copper or the like is inserted into a through hole 6 of a board 4 and soldered to form a double-sided copper foil portion 7.
．． There was something that electrically connected 8. This method requires a lot of work on both ends of the dowel 6.

Further, in soldering, electrical connection is made by passing the solder through the entire solder dip bath and rising from the bottom to the top, but there is a risk that the copper foil portions 7 and 8 on one side may cause a connection failure.

Figure 3 uses a cylindrical eyelet 9 with a broken part, but it makes full use of the capillary phenomenon, and although the soldering properties are better, the eyelet 9 still expands and contracts due to temperature changes. disconnection occurred due to not doing so. Furthermore, due to the mechanical processing involved when inserting this eyelet 9 into the through hole 6, the eyelet 9 is required to have a height of 4X or more for a material thickness of about 1% of the substrate 4, which becomes an obstacle to miniaturizing the entire device. was. As a method to solve all of the above-mentioned drawbacks, as shown in FIG.
A jumper formed at 1.121 and inserted into this through hole 11.12? There is a fM13 that connects the copper foil parts on both sides so that it can follow the expansion and contraction of the thickness of the board 1o due to temperature changes, but it requires a large area, resulting in high costs, and the soldering part doubles. There were drawbacks.

The present invention eliminates all of the above drawbacks, and an embodiment of the present invention will be described below with reference to all the drawings.

FIG. 6 shows a cross-sectional view of an example of a printed wiring board used in the present invention. Copper foil parts 61, 52' (
6, with a through hole 63 penetrating through the center thereof. The inner peripheral surface of this through hole 63 can be plated or a through hole pin (eyelet of various shapes) can be fully inserted.

Both copper foil portions 51 and 52 are electrically connected using a rubber-based conductive adhesive having plasticity.

An embodiment of the present invention will be described using FIG. 6.

The figure shows copper foil portions 61.5 formed on both sides of the insulating substrate 60.
2? : Through-holes 53 and 53' are formed.

The sectional view shows a state in which one of the through holes 63 remains as it is and the lead terminal eoa'l of the electrical component 6o is inserted into the other through hole 63'. The latter example is the same as the electrical component insertion state of a general printed wiring board.

Figure B shows the double-sided printed wiring board in the inserted state, which has been soldered around the through hole 63 and through hole 53' by applying a general half-finishing process.

By performing the solder dip treatment in this way, the through holes 53
lower copper foil portion 62. Solder 61 can be attached to the lower copper foil portion 62 and the lead pusher 60& on the side of the through hole 53', and the lower copper foil portion 62 and the lead terminal 601L can be electrically connected by the solder 61. can. After this, as shown in FIG. Lead terminal 601L
By applying conductive adhesive 62 having plasticity to the through holes 63 including 'i' from the upper copper foil part 61 side, the conductive adhesive 62 enters into the through holes 63 and solder. 61 and the conductive adhesive 62 are electrically connected, and the upper copper foil part 61 and the lead terminal 60 & are electrically connected by the conductive adhesive 62 on the side of the through hole 53', whereby the upper copper foil part 61 An electrical connection between the lower copper foil portion 62 and the lower copper foil portion 62 is established.

As explained above, according to the present invention, a single-sided printed wiring board is provided with through holes that penetrate through the copper foil portions on both sides.

The lower copper foil part is soldered using a solder dip tank, etc., and the upper copper foil part is completely coated with a plastic conductive adhesive so that it enters the through hole, thereby removing the solder and conductive adhesive. By electrically connecting all the copper foil parts on both sides through the double-sided printed wiring board, there is no need for plating or through-hole pins. Since this can be absorbed by the conductive adhesive, the electrical connection is ensured and the reliability is improved without causing any cracks or damage due to the deformation of the insulating substrate.

[Brief Description of the Drawings] Fig. 1, Fig. 2, Fig. 3, and Fig. 4 are diagrams for explaining the connection method of double-sided printed wiring boards in the conventional example, respectively, and Fig. 6 is a double-sided printed wiring board used in the present invention. FIGS. 6A, 6B, and 6C are cross-sectional views showing the structure of a printed wiring board. FIGS. 60... Insulating substrate, 61... Upper copper foil part, 62... Lower copper foil part, 53.53'...
...Through hole, 80...Electric component, 80a...
...Lead terminal, 61...Solder, 62...
...A conductive adhesive with plasticity.

Claims (2)

[Claims] (1) A printed wiring board with copper foil parts formed on both sides is provided, and a through hole is bored through the copper foil parts on both sides of the board, =
On the other copper foil side, solder is connected using a solder dip tank, etc. From the other copper foil side, a conductive adhesive with plasticity is applied to the other copper foil part and the through hole. A method for connecting a double-sided printed wiring board, comprising electrically connecting copper foil parts on both sides through solder on the foil part side and the conductive adhesive having plasticity. (2) Lead terminals of electrical components are inserted into the through holes. Solder connects this lead terminal and one copper foil part. Plasticity 'f of connecting the lead terminal and the other copper foil part:
2. The method for connecting double-sided printed wiring boards according to claim 1, wherein the copper foil portions on both sides are electrically connected through the conductive adhesive and the lead terminal.