JPH04109691A - Connecting structure of printed wiring board - Google Patents

Abstract

PURPOSE:To connect by soldering at low cost and improve reliability at a soldering part by a method wherein soldering is performed in such a condition that a comblike part is deformed at a gentle angle of 45 deg. or less and fixed to other printed boards with a elasticity. CONSTITUTION:A tip of a comblike part 3 of a flexible printed board 1 is inserted into a slit 8 provided in the vicinity of a resist eliminating part 7 which is a land for connecting in a rigid printed board 5. Next, the comblike part 3 is deformed at a gentle angle of almost 45 deg. or less so as to project at least in an edge 8a on the lower side within the slit 8 and is fixed to the rigid printed board with elasticity. Then, in these conditions, a soldering swollen part 9 is soldered to connect to patterns 2, 6 electrically. Accordingly, a soldering deposited area can sufficiently be secured and soldering operations become easy. Thus, a connecting structure with high reliability at low costs can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a connection structure for printed wiring boards, and particularly to a connection structure by soldering between a flexible printed circuit board and another printed circuit board.

[Prior Art] Conventionally, when connecting a flexible printed circuit board and a rigid printed circuit board by soldering, for example, Figs.
As shown in the figure, the flexible printed circuit board 30 and the rigid printed circuit board 31 are stacked vertically, and the plurality of comb-tooth-shaped portions 32 of the flexible printed circuit board 30 are positioned in the resist print removal section 33 of the rigid printed circuit board 31 using a pin 39.
The flexible printed circuit board 30 and the rigid printed circuit board 31 are electrically connected on a plane by aligning the printed circuit boards 30 and 31 and forming solder mounds 34 by applying solder to the surface portions.

In the same figure, 35 is a copper foil pattern on a flexible printed circuit board, 36 is a cover film on a flexible printed circuit board, 37 is a copper foil pattern on a hard board, 3
8 is a resist printing section on a hard substrate, and 40 is a fixing screw.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional technology, if the flexible printed circuit board 30 is a copper-clad single-sided flexible board with only the front side, electrical connection must be made only with the solder mounds on the front surface. Therefore, there is a problem in that the solder welding area cannot be secured unless the area of the resist print removal section 33 on the hard printed circuit board 31 side is made large.

Furthermore, since there is no copper foil on the base film side of the flexible printed circuit board 30, no solder connection is made between the opposing surfaces. As a result, an unstable gap 41 is created between the overlapping parts of the flexible printed circuit board 30 and the rigid printed circuit board Fi 31 where they are not connected, so soldering is likely to cause connection failures in the parts due to environmental changes, external stress, etc. There was a problem. In addition, by making the flexible printed circuit board 30 a double-sided copper-clad board, providing copper foil on the opposite surfaces on the back side, and soldering the resist removed part on the hard printed circuit board 31 side, the gap that occurs between the two boards can be reduced. Although there is a method to improve the reliability of soldering by burying it, another problem arises in that the process of making the flexible printed circuit board 30 double-sided and adding the solder plating process to the hard printed circuit board 31 results in a large increase in cost.

The present invention aims to solve the above problems. That is, the present invention provides a connection structure for a printed wiring board that can secure a sufficient solder welding area, improve workability and reliability during soldering, and avoid an increase in cost. The purpose is to provide

[Means for Solving the Problems] In order to achieve the above object, the present invention has a plurality of comb-shaped connecting portions in a part of a flexible printed circuit board,
In a connection structure in which a comb-shaped portion and an exposed copper foil land portion of another printed circuit board are connected by soldering with the base film surface of the flexible printed circuit board facing the pattern surface side of another printed circuit board and overlapped, The other printed circuit board has a slit provided near the land portion, and the comb-shaped portion of the flexible printed circuit board is inserted into the slit and abuts at least the lower edge portion of the slit, Moreover, the soldering is performed while the comb-shaped portion is deformed at a gentle angle of approximately 45 degrees or less and is elastically fixed to the other printed circuit board, and the two printed circuit boards are connected. It is assumed that

[Function] According to the present invention, a slit is provided in the vicinity of the land portion of another printed circuit board, and the comb-shaped portion of the flexible printed circuit board is inserted into the slit and comes into contact with at least the lower edge portion of the slit. As shown, the comb-shaped part is deformed at a gentle angle of approximately 45 degrees or less, and soldering is performed while it is elastically fixed to another printed circuit board, so a sufficient solder welding area is secured. Soldering is an easy process, and a highly reliable connection structure can be obtained at low cost.

[Embodiment] FIG. 1 is a plan view showing a first embodiment of the present invention, and FIG. 2 is an enlarged sectional view thereof.

= In Fig. A substrate, 6 is a pattern wired on the substrate 5, 7 is a resist removal section, 8 is a slit to be described later, 9 is a solder mound electrically connecting the patterns 2 and 6, and 10 is the flexible plate. a positioning pin for aligning the comb-shaped portion 3 of the printed circuit board 1 and the resist removal portion 7 of the rigid printed circuit board 5; reference numeral 11 denotes a fixing screw for fixing the flexible printed circuit board 1 and the rigid printed circuit board 5 after positioning; Reference numeral 12 denotes a housing to which two substrates 1.5 are fixed.

The slit 8 is provided near the land portion of the hard printed circuit board 5, and the comb-shaped portion 3 is inserted into the slit 8.

In the above configuration, the tip of the comb-shaped portion 3, which is a terminal for connection to the rigid printed circuit board 5 of the flexible printed circuit board 1, is inserted into the slit 8 near the resist removed portion 7, which is a connection land of the rigid printed circuit board 5. insert. Then, the positioning holes of the flexible printed circuit board 1 are aligned with the positioning bins 10 provided in the casing 12, and the flexible printed circuit board 1 is fixed with the fixing screws 11. In this state, as shown in FIG. 2, the comb-shaped portion 3 of the flexible printed circuit board 1 is arranged so that its tip end touches the lower edge 8a of the slit 8. Due to the elastic force of the printed circuit board 1 to return to a flat surface and the force for fixing the fixing screws 11 onto the substrate, the printed circuit board 1 elastically abuts against the edge portion 8a of the slit 8, forming a gentle slope and being fixed. By forming this connection part into a toothed shape, the elastic force of the flexible printed circuit board 1 is adjusted when it abuts against the edge 8a in the slit 8, making it easier to form a gentle slope. In this way, solder is applied to the tooth-shaped portion 3 and the resist removed portion 7 of the flexible printed circuit board 1 to connect them.

In the solder connection between the gentle slope part of the comb-tooth shaped part 3 and the resist removed part 7 obtained in this way, the solder welding area of each board is smaller than that of the conventional connection structure.
The area of the connecting portion on the surfaces of the two substrates can be made small by ensuring the same area. Furthermore, since the comb-shaped portion 3 is elastically fixed to the hard printed circuit board 5, it is possible to eliminate gaps that may remain unstable during solder welding between the flexible printed circuit board 1 and the hard printed circuit board 5. It is possible to prevent deterioration in reliability due to soldering such as peeling.

FIG. 3 is a plan view showing a second embodiment of the present invention, and FIG. 4 is an enlarged sectional view thereof.

In this second embodiment, the flexible printed circuit board has two comb-shaped connecting portions, and the rigid printed circuit board side is also inserted into two slits, thereby eliminating the need for fixing means such as screws. .

3 and 4, 15 is a flexible printed circuit board, 16 is a wiring pattern, 17a and 17b are two comb-shaped parts, 18 is a cover film, 19 is a rigid printed circuit board, and 20 is the rigid printed circuit board. The patterns 19, 21a and 21b are the two comb-shaped portions 17.
Rigid printed circuit board 19 provided corresponding to a and 17b
resist removal section 22a.

22b are two slits 23a, 2 provided at positions corresponding to the two comb-shaped portions 17a, 17b;
3b is a solder mound on each of the comb tooth-shaped portions 17a and 17b, and 24 is a positioning bottle.

In this second embodiment as well, similarly to the first embodiment described above, the comb-shaped portion 17a of the flexible printed circuit board 15 is
, 17b is a resist removal section 21a for soldering the hard printed circuit board 19.

The side substrates 15 and 19 are inserted into the slits 22a and 22b provided near 21b, and the side substrates 15 and 19 are positioned using the positioning pins 24. In this state, as shown in Figure 4,
Comb tooth shaped portion 17a.

17b are the edge portions 2 of the slits 22a and 22b, respectively.
2c and 22d elastically. In this state,
Since the comb tooth-shaped portions 17a and 17b are in contact with the slits 22a and 22b almost symmetrically with respect to the positioning pin 24, the flexible printed circuit board 15 is held on the hard printed circuit board 19 by the elastic force of the board work 5. has been done. Therefore, even if the flexible printed circuit board 15 and the rigid printed circuit board 19 are not fixed to the housing by the fixing bus as in the first embodiment described above, the comb-shaped portions 17a and 17b of the flexible printed circuit board 15 can be elastically held. It is possible.

[Effects of the Invention] As explained above, according to the present invention, a slit is provided near the land portion of another printed circuit board, and
The comb-shaped portion of the flexible printed circuit board is inserted into the slit and comes into contact with at least the lower edge portion of the slit, and the comb-shaped portion is deformed at a gentle angle of about 45 degrees or less and becomes elastic. Since soldering is performed while the solder is fixed to the other printed circuit board, the total area of the solder connection portion on the board can be reduced while securing the solder welding area on the two printed circuit boards. . In addition, since the elasticity of the comb-shaped portion allows it to be elastically fixed to the edge portion in the slit of another printed circuit board, the workability during soldering is improved, and solder connection is possible at low cost. This has the effect of improving the reliability of the unit.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a first embodiment of the present invention, FIG. 2 is an enlarged sectional view of FIG. 1, FIG. 3 is a plan view showing a second embodiment of the present invention, and FIG. 3 is an enlarged sectional view of FIG. 3, FIG. 5 is a plan view showing an example of the conventional technology, FIG. 6 is an enlarged sectional view of FIG. 5, and FIG. 7 is a perspective view of FIG. 5. 1...Flexible printed circuit board 3...Comb tooth shaped part 5... Rigid printed circuit board 7
...Resist removal part 8...Slit 8a...Edge part 9...Solder mound part and 4 others Fig. 1 Fig. 3 Fig. 2 Fig. Fig.

Claims (1)

[Scope of Claims] 1. A flexible printed circuit board having a plurality of comb-shaped connecting portions in a part thereof, and stacked with the base film surface of the flexible printed circuit board facing the pattern surface side of another printed circuit board. A connection structure in which a comb-tooth-shaped portion and an exposed copper foil land portion of another printed circuit board are connected by soldering includes a slit provided in the vicinity of the land portion of the other printed circuit board, and the slit is provided with the The comb-shaped portion of the flexible printed circuit board is inserted and abuts at least the lower edge portion of the slit, and the comb-shaped portion is deformed at a gentle angle of about 45° or less to elastically move the flexible printed circuit board. A connection structure for a printed wiring board, characterized in that the two printed circuit boards are connected by soldering while being fixed to the printed circuit board. 2. The printed wiring board connection structure according to claim 1, wherein the other printed circuit board is a rigid printed board.