JPS6365698A - Method of connecting boards - Google Patents

Abstract

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

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a joining method for joining or bonding a flexible substrate to another flexible substrate or a rigid substrate.

[Conventional technology]

When a flexible board (FPC board) and a rigid board (paper phenol board, etc.) are bonded, conventionally, as shown in FIG. There is a method of aligning the holes of a flexible board 3 having holes provided with solder lands 1, overlapping them, and soldering and joining two solder lands 1.2 through the holes, or as shown in Fig. 4. As shown, a method is used in which holes with soldering lands 2 and 1 are provided around the periphery of both the rigid board 4 and the flexible board 3, the holes of both are aligned and overlapped, and the lead wires 17 of the components are passed through and soldered. It is.

Incidentally, related methods for joining such flexible substrates and rigid substrates include, for example, Japanese Patent Application Laid-Open No. 1983-1999.
No. 250695 is known.

[Problem that the invention seeks to solve]

In such a conventional technique, when the flexible substrate 3 and the rigid substrate 4 are bonded by the method shown in FIG.
If 5 is mixed in, it not only causes poor contact between the substrates and poor conduction, but also causes poor /M soldering and peeling.

Furthermore, if the component leads 17 are used for bonding using the method shown in FIG. 4, electrical contact will be better than in the case shown in FIG. There is a problem in that not only the packaging density is lower than that, but also the degree of freedom in the position of the soldered part is reduced depending on the size of the components.

An object of the present invention is to provide a method for bonding boards together, which makes it possible to use a surface mounting method and reduce soldering defects.

[Means for solving problems]

In order to achieve the above object, the present invention provides a soldered land on a part of the edge of a hole formed on the flexible substrate side where the two overlap when joining a flexible substrate and a rigid substrate, and Are they positioned so that the soldered land provided on the board does not cover the entire hole in the flexible board?

Alternatively, set the shape of the soldering lands so that the two soldering lands are soldered through the holes.

The two substrates are not limited to the case of a flexible substrate and a rigid substrate, but can be similarly applied to the case of bonding flexible substrates together.

[Effect]

Because soldering land is not provided all around the hole on the flexible board, and the soldering land on the rigid board is shifted horizontally from the hole, air bubbles, etc. that get into the soldered area are removed from the hole. Since the solder is not trapped in the solder pad and comes out through the misalignment between the hole and the soldering land, poor soldering can be prevented.

Furthermore, since no holes are provided on one of the substrates, the area of the substrate can be used effectively, and the mounting density of components can be increased.

〔Example〕

Hereinafter, one embodiment of the present invention will be described with reference to FIG. The soldering land 10 of the flexible board is formed in a three-moon shape on a part of the edge of the hole as shown in FIG. As shown in (a) and (b), the soldering lands 2 are overlapped and soldered so as not to cover the entire hole. The state after soldering is shown in Figures 2(a) and (b).

Air bubbles and the like in the soldered portion 5 can escape in the direction of the arrow shown in FIG. 2(b), thereby preventing soldering defects.

Further, when the present invention is used, there is no need to make holes on the rigid substrate 4 side, so it is possible to increase the mounting density on the rigid substrate 4 side by surface mounting.

Although this embodiment is an example of bonding a flexible substrate and a rigid substrate, the same effect can be obtained by the same method when bonding flexible substrates together.

〔Effect of the invention〕

According to the present invention, soldering defects are prevented, so the efficiency of board manufacturing is improved. According to the applicant's experimental results, the defect rate decreased from about 20 when the present invention was not used to about 2% when the present invention was used.

As described above, by using the present invention, it is possible to almost eliminate the inclusion of air bubbles, etc. in the bonding of flexible substrates, significantly reduce soldering defects, and almost eliminate the need for a correction process. It also reduces thermal deterioration of parts, increases reliability, and reduces costs by improving productivity.
It has great industrial value.

[Brief explanation of drawings]

Figures 1(a) and 1(b) show the joint surfaces of a flexible board and a rigid board before soldering to explain an embodiment of the present invention. (a
It is a sectional view taken along the line A-A' of i. Figure 2 (ω, (b) is a top view of the main part showing the bonding surface between the flexible board and the rigid board after soldering, and a sectional view taken along the line A-X in (a). Figures 3 and 4 are It is a cross-sectional view of the bonding surface of a flexible board and a rigid board to explain the conventional method. 1.10 Soldering land on the flexible board side, 2
．． 20...Rigid board side soldered land, 3...
Flexible board, 4... Rigid board, 5... Solder, 15...
・Public foam, 17...Parts lead.

Claims (1)

[Claims] 1 When joining flexible boards together or a flexible board and a rigid board, make a hole in one flexible board, provide a soldered land on a part of the edge of this hole, and connect the soldered land of the other board to the above hole. A board bonding method characterized in that the boards are arranged in a staggered manner so as not to block the entire board, and soldering is performed between the soldering lands on both boards.