JPH0353516Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a double-sided printed circuit board in which through-holes are not formed and has highly reliable solder adhesion.

[Prior art and problems to be solved by the invention] Conventional double-sided printed circuit boards include those shown in FIGS. 1A and 1B and FIG. 2. In the figure, 1 is a double-sided printed circuit board, 2 is a copper foil land formed on both sides of the double-sided printed circuit board 1, 7 is an electric component mounting hole for attaching the electric component 3 to the double-sided printed circuit board 1, and 8 is a through hole. It is.

In order to electrically connect the electric component 3 to the copper foil land 2 of this double-sided printed circuit board 1, the electric component 3
Insert the lead wire 4 into the electrical component mounting hole 7 and solder 5.
This is done by attaching. Thereby, the lead wire 4 is mechanically fixed and electrically connected to the copper foil land 2. At this time, the inside of the electrical component mounting hole 7 is filled with the solder 5 through the through hole 8,
firmly fixed.

Therefore, in this conventional example, it is necessary to form through holes in order to attach electrical components to the double-sided printed circuit board, and the first drawback is that the double-sided printed circuit board becomes expensive. Second, since the inside of the electrical component mounting hole is filled with solder, it is difficult to remove the electrical component once it is mounted for repair or replacement. Furthermore, when the lead wires of electrical components are long, soldering defects may occur.

Therefore, a device shown in FIG. 3 was developed that solved the above-mentioned drawbacks. Double-sided printed circuit board 1 shown in Figure 3
In this case, the through hole 8 for connecting both sides of the printed circuit board is not formed, and as shown in FIG.
It connects both sides of the At this time, there is a cavity 9 in the component mounting hole 7 which is not filled with the solder 5. In this example, since the through hole 8 is not formed, the double-sided printed circuit board 1 can be manufactured at low cost.
The electrical component 3 can be removed from the printed circuit board 1 even after the electrical component is attached.

However, as shown in FIG. 5, the solder 5 has a drawback that blowholes 6 occur with a very high probability, reducing the reliability of soldering.

[Purpose of the invention] The present invention was made to solve the above-mentioned drawbacks, and by preventing the occurrence of blowholes on double-sided printed circuit boards without through-holes, it is possible to attach electrical components by soldering. To provide a double-sided printed circuit board that facilitates subsequent removal of components and improves soldering reliability.

[Means for Solving the Problems] The present invention, which was made to achieve the above object, is to form a copper foil land on at least one side of a double-sided printed circuit board in the vicinity of the electrical component mounting hole without making contact with the mounting hole. It is characterized by what it did.

[Example] An example of the present invention is shown in FIGS. 6 and 7. In the drawings, the same members as in the conventional example are indicated by the same reference numerals.

The copper foil land 2 on the lower surface of the printed circuit board 1 shown in FIG. 6 has the same shape as the conventional copper foil land (FIG. 1b). However, the copper foil land 2 on the top surface is not in contact with the electrical component mounting hole 7, but is formed near the mounting hole 7, as shown in FIG.

To connect the electrical component 3 to the double-sided printed circuit board 1 by soldering, the lead wire 4 of the electrical component 3 is inserted into the electrical component mounting hole 7, and then the upper surface of the double-sided printed circuit board 1 is first soldered. However, since the shape of the copper foil land 2 on the top surface is formed near the electrical component mounting hole 7 without contacting it, the electrical component mounting hole 7
There is no possibility of occluding the ends of the

Next, the lower surface of the double-sided printed circuit board 1 is soldered to connect the lead wire 4 and the copper foil land 2. At this time, the generated gas escapes outward from the gap 18 of the electrical component mounting hole 7 on the upper surface of the double-sided printed circuit board 1 to which no solder is attached, so that no blowhole is generated and proper soldering is performed.

The shape of the copper foil land of the present invention is not limited to the shape shown in the embodiments, but may be any shape that does not completely block the electrical component mounting hole 7 with solder.
Further, such copper foil lands may be used on both sides of a double-sided printed circuit board.

[Effects] As described above, according to the present invention, since no through holes are formed, the board can be manufactured at low cost, and
It also becomes easier to remove electrical components after soldering.

Furthermore, since the copper foil land on at least one side of the double-sided board does not come into contact with the mounting hole, highly reliable soldering can be performed without blowholes.

Furthermore, since the copper foil lands are formed near the electrical component mounting holes, soldering can be performed reliably without causing soldering defects even if the leads of the electrical components are long. In addition, the copper foil lands that do not come into contact with the electrical component mounting holes are formed on the mounting surface of the electrical component body, so the lands can be soldered into the mounting holes without being constrained by the length of the electrical component lead wires. It can be formed in a position that does not cause occlusion.

[Brief explanation of the drawing]

Figure 1a is a diagram showing a conventional double-sided printed circuit board,
Figure 1b is a diagram showing the conventional copper foil land shape;
The figure shows the state of solder adhesion on the board shown in Fig. 1, Fig. 3 shows a conventional double-sided printed circuit board without through holes, and Figs.
FIG. 6 is a double-sided board according to an embodiment of the present invention, and FIG. 7 is a diagram showing the copper foil land shape of the board in FIG. 6. 1...Double-sided printed circuit board, 2...Copper foil land,
5...Solder, 7...Electric component mounting hole, 18...Gap.

Claims (1)

[Claims for Utility Model Registration] Electrical component mounting holes without through-holes are formed on the board, copper foil lands are formed on both sides of the board, and electrical parts are mounted in the electrical component mounting holes, and both sides of the board are provided with copper foil lands. In a double-sided printed circuit board in which the copper foil lands of the double-sided printed circuit board and the electric component are connected and fixed by soldering, the copper foil lands on the mounting surface of the electric component main body of the double-sided printed circuit board do not have a notch and are connected to the electric component. A double-sided printed circuit board characterized in that the printed circuit board is formed near the mounting hole without contacting the mounting hole.