JPH05152738A - Connection method of printed wiring board - Google Patents

Abstract

PURPOSE:To connect printed wiring boards, with high density at a low cost. CONSTITUTION:The respective connection lands 1a of through holes 8 formed in a first printed board 2 and a second printed board 3 are mutually superposed, thereby forming a continuous through hole 8. A conductive pin 5 shorter than the total length L of the through hole 8 is inserted into the continuous through hole 8. The tip single side of the conductive pin 5 is fixed to the connection land 1a by using solder 6, thereby electrically connecting the first and the second printed wiring boards 2, 3. The part which is electrically connected as the result of fixation of the solder 6 is sealed by using noncoductive material 7.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of connecting printed wiring boards.

[0002]

2. Description of the Related Art A conventional printed wiring board connection method is shown in FIG.
And FIG. 4 will be described.

In FIG. 3, in the conventional printed wiring board connecting method, a through hole 8 is formed in an overlapping portion of the first and second printed wiring boards 2 and 3, and copper or the like is formed on the inner wall surface of the through hole 8. The metal plating 9 is applied to electrically connect the first and second printed wiring boards 2 and 3 to each other.

Another conventional connection method shown in FIG.
The connection lands 1a of the through holes 8 formed on the first and second printed wiring boards 2 and 3 are overlapped with each other, and the conductive pin 10 longer than the total length L of the continuous through holes 8 formed by this overlap is formed. It is inserted into the continuous through hole 8.

After that, both ends of the conductive pin 10 and both sides of the opening end of the through hole 8 are fixed by solder 6 to electrically connect the superposed first and second printed wiring boards 2 and 3 to each other. Is.

[0006]

However, according to the conventional through-hole connection method by metal plating as shown in FIG. 3, when the printed wiring board is manufactured, the first and second
Since the process of electrically connecting the printed wiring boards 2 and 3 to each other becomes complicated, there is a problem that the manufacturing cost becomes high.

In the conventional connecting method using conductive pins as shown in FIG. 4, since the conductive pins 10 are longer than the total length L of the continuous through holes 8, they are fixed to both ends of the conductive pins 10. There is a problem that the solder 6 is exposed on both sides of the opening end of the continuous through hole 8 and the printed wiring board cannot be connected to both sides of the same area.

Therefore, an object of the present invention is to provide a method of connecting printed wiring boards, which enables the printed wiring boards to be connected at low cost and with high density.

[0009]

In order to achieve the above object, the present invention is a method of connecting at least two printed wiring boards having wiring patterns, wherein a through formed on each printed wiring board. Printed wiring boards superposed by overlapping connecting lands of holes and inserting conductive pins shorter than the total length of continuous through holes formed by this superposition into the continuous through holes and soldering Is electrically connected.

Further, it is characterized in that a portion electrically connected by the soldering is sealed with a non-conductive material.

[0011]

By inserting a conductive pin shorter than the entire length of the through hole into a continuous through hole formed by overlapping the connecting lands, one side of the opening end of the through hole in which the conductive pin is inserted is inserted. The printed wiring board can be connected to both surfaces of the same area without exposing the solder.

Further, since the conductive pin is simply inserted into the continuous through hole and soldered, the connection can be made at a low cost.

Further, the non-conductive material which seals the portion which is conductively connected by soldering increases the connection strength and improves the connection reliability.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a printed wiring board connecting method according to the present invention (hereinafter referred to as the present method) will be described in detail below with reference to FIGS. 1 and 2.

In FIGS. 1 and 2, three printed wiring boards on which the wiring pattern 1 is formed are connected by this method, and one of the three first printed wiring boards 2 is
It is a 4-layer printed wiring board having a thickness of 1.6 mm, and the other two second and third printed wiring boards 3 and 4 are single-sided flexible printed wiring boards.

Here, through holes 8 for inserting pins are formed in each of the first, second and third printed wiring boards 2, 3 and 4.
Are formed on both sides of the opening end of the through hole 8 of the first printed wiring board 2 and on one side of the opening end of the through hole 8 of the second and third printed wiring boards 3 and 4, the connection land 1 is formed.
a is formed integrally with the wiring pattern 1.

The connecting land 1a has a diameter of φ1.3.
mm, the through hole 8 is formed with a diameter of φ0.8 mm, and the inner wall surface of the through hole 8 of the first printed wiring board 2 is plated with a metal 9 so as to be integrated with the connection land 1a.

On the other hand, the conductive pin 5 inserted into the through hole 8 has a length of 1.2 mm and a pin diameter of 0.4 mm.
mm.

Hereinafter, as one embodiment of the present method, first and second embodiments in which the first, second and third printed wiring boards are electrically connected will be described.

First, in the first embodiment, the connection lands 1a of the through holes 8 formed in the first and second printed wiring boards 2 and 3 are overlapped with each other, and the continuous through holes formed by this overlap are formed. A conductive pin 5 shorter than the total length L of 8 is inserted into the continuous through hole 8.

Next, solder 6 is applied to the connection lands 1a of the second printed wiring board 3 to fix one end of the conductive pin 5 at one end, and the first and second printed wiring boards 2 and 3 are electrically connected to each other. Connecting.

Further, the third printed wiring board 4 is conductively connected to the opposite side of the same area of the first printed wiring board 2 to which the second printed wiring board 3 is conductively connected in the same manner as the above method.

On the other hand, in the second embodiment, similarly to the first embodiment, after the first, second and third printed wiring boards 2, 3 and 4 are electrically connected, the portions which are electrically connected by the solder 6 are not connected. An epoxy resin, which is one of the conductive materials 7, is applied.

The conductive pin 5 is preferably preliminarily solder-plated at its tip, the pin diameter is preferably about 50% of the through hole diameter, and the length is the length shown in the following formula. Is desirable.

Length of conductive pin = length of through hole on pin insertion side +
Length of through hole on opposite side of pin insertion × 0.75 or more In the method of the first embodiment, continuous through hole 8 is formed.
By inserting the conductive pin 5 shorter than the total length L into the through hole 8, the solder 6 is not exposed on the opposite side of the through hole 8 into which the conductive pin 5 is inserted. , The third printed wiring boards 3 and 4 can be connected, and the printed wiring boards can be connected at high density.

Further, since the conductive pin 5 is simply inserted into the continuous through hole 8 and soldered, the connection can be made at a low cost.

Further, in the method of the second embodiment, in addition to the effect of the first embodiment, the non-conductive material which seals the portion electrically connected by soldering increases the connection strength and improves the connection reliability.

Table 1 compares the mounting densities of the connecting portions according to this comparative example and the first embodiment with the conventional connecting method shown in FIG. 4 as a comparative example. As is clear from this table 1,
It is understood that this method has a much higher packaging density than the conventional method.

[0029]

[Table 1]

[0030]

As is apparent from the above description, according to the printed wiring board connecting method of the present invention, the conductive pin shorter than the entire length of the continuous through hole is inserted into the continuous through hole. Since the solder is not exposed on the opposite side of the through hole into which the conductive pin is inserted, the printed wiring boards can be connected to both surfaces of the same area, and the printed wiring boards can be connected at high density.

Further, since the conductive pins are simply inserted into the continuous through holes and soldered, the connection can be made at a low cost.

Further, in addition to the above-mentioned effects, the non-conductive material for sealing the portion which is conductively connected by soldering increases the connection strength and improves the connection reliability.

[Brief description of drawings]

FIG. 1 is a plan view showing a connection state of printed wiring boards connected by this method.

FIG. 2 is a sectional view of AA ′ in FIG.

FIG. 3 is a cross-sectional view showing a connected state of printed wiring boards connected by a conventional method.

FIG. 4 is a cross-sectional view showing a connected state of printed wiring boards connected by another conventional method.

[Explanation of symbols]

 1 Wiring Pattern 1a Connection Land 2 First Printed Wiring Board 3 Second Printed Wiring Board 4 Third Printed Wiring Board 5 Conductive Pin 6 Solder 7 Non-Conductive Material 8 Through Hole 9 Metal Plating 10 Conductive Pin L Total Length of Through Hole

Claims (2)

[Claims] 1. At least two wiring patterns are formed.
A method for connecting one or more printed wiring boards, in which the connecting lands of the through holes formed on each printed wiring board are overlapped, and the conductive land is shorter than the total length of the continuous through holes formed by this overlapping. A method for connecting printed wiring boards, comprising inserting pins into the continuous through holes and soldering the printed wiring boards so that the stacked printed wiring boards are electrically connected to each other. 2. The method for connecting a printed wiring board according to claim 1, wherein a portion electrically connected by soldering is sealed with a non-conductive material.