JPH06268350A - Printed wiring circuit device - Google Patents

Abstract

PURPOSE:To prevent formation of solder bridge due to excess solder or insufficient soldering strength due to insufficient solder when solder lands are soldered while crossing two printed wiring boards. CONSTITUTION:Two printed wiring boards 1, 2 are crossed perpendicularly to arrange a plurality of lands of both boards while abutting each other with the tip part of the solder land 20 being set narrower than the width thereof. This arrangement suppresses bulging of solder thus restraining solder bridge. In case of insufficient solder, thickness of solder increases in the tilting direction of the printed board 2 thus restraining breakage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring circuit device having an improved solder land for a printed wiring board.

[0002]

2. Description of the Related Art FIG. 13 shows a conventional example. In the figure, reference numeral 1 denotes a first printed wiring board, and a second printed wiring board 2 is attached to a slit hole 5 at right angles. 3 is a soldering land continuously arranged in parallel on the second printed wiring board 2, and 4 is a soldering land continuously arranged on the first printed wiring board 1 so as to abut against the soldering land 3. It is configured.

Next, the soldering lands 3 and 4 abutted against each other
I will explain about the soldering. 14 is a view A in FIG.
The state of the butt land viewed from the side is shown, 5 is a slit hole, 5a is a slit, and is a gap between the soldering land 3 and the slit hole 5. FIG. 15 shows a state as viewed from the direction B in FIG. 13 after performing appropriate soldering.
Is a solder, and when properly soldered, the shape is as shown in the figure, and the first printed wiring board 1 and the second printed wiring board 2 are connected. A resist layer 7 is printed with resist ink on portions of the printed wiring boards 1 and 2 which are not to be soldered to prevent soldering.

FIG. 16 shows a state in which continuous butted lands are connected by soldering. The soldering iron 100 is sequentially attached from the end, but the left end shows an appropriate amount of soldered state.
When the amount of solder is large, solder swelling occurs due to the surface tension of the solder such as 8 and 9. Also, if the lands with excessive amount of solder continue, solder blisters 10 and 11 will be generated, and the next solder blisters 12 and 13 will be generated before the solder of the solder blisters 11 cools and solidifies. They are connected by molten solder and become a solder bridge due to surface tension.

On the other hand, FIG. 17 shows a case in which the soldering lands are arranged in a displaced manner, and if soldering is carried out in the same manner as described above, a proper amount of soldering will result in solder blisters 14, but the amount of soldering will be large. If there is too much solder blisters 15, 16, 17,
18, the blisters generated in FIG. 17 are closer to the land 3 and the adjacent land 4 than the solder blisters in FIG. 16, resulting in a condition in which a solder bridge is more likely to occur. Prone.

FIG. 18 shows a soldering state in which the amount of solder is too small.
Shown in. FIG. 19 shows a cross section taken along the line EE of FIG. 18, in which the central portion of the portion to which the solder 6 is connected is thinly spread as shown in the drawing, and the second printed wiring board 2 is broken in the falling direction. The shape is easy to do.

Next, as shown in FIG. 20, the second printed wiring board 2
If the slit hole 5 is larger than the plate thickness of
If the lands 3 and 4 are excessively soldered, the solder dripping 19 may occur and short-circuit with other patterns and the back surface pattern may occur.

As an example of forming an electronic circuit using orthogonal printed wiring boards, there is one disclosed in Japanese Utility Model Laid-Open No. 4-68579. This land portion has a structure similar to that of the conventional example. However, the purpose of the connection is that the connection by soldering is better than the connection by the connector, and the contact characteristics can be prevented.

[0009]

Since the conventional printed wiring board having a butt structure has the land structure as described above, it is necessary to pay attention to the amount of solder and solder it so as not to cause dripping of solder or bridging. However, there is a problem in that it takes a lot of time and work, and there are many corrections, and it is difficult to find a dripping from the outside by visual inspection.

The present invention has been made in order to solve the above-mentioned problems, and an object thereof is to suppress the occurrence of solder bridge and solder dripping and to improve work efficiency.

[0011]

In the printed wiring circuit device according to the present invention, at least one printed wiring board among two printed wiring boards arranged so that a plurality of soldering lands on both sides abut each other. The width of a portion of the wiring board to which the solder is attached to the soldering land is narrowed in the vicinity of the abutting portion of the soldering land.

Further, the second printed wiring board is fitted in the slit hole of the first printed wiring board, and the position of the tip of the soldering land of the first printed wiring board is set from the end surface of the slit hole. The first printed wiring board and the first printed wiring board are formed so as to be spaced apart from each other, and the width of a portion of the first printed wiring board to which the solder is attached is narrowed in the vicinity of the abutting portion of the soldering land.

Further, the width of the soldering land is narrowed near the abutting portion of the soldering land.

Further, a resist layer is formed on the soldering land so that a portion to be soldered in the vicinity of the abutting portion of the soldering land becomes narrow.

[0015]

In the printed wiring circuit device according to the present invention, the width of the portion to be soldered to the soldering land is narrowed in the vicinity of the abutting portion of the soldering land, so that the soldering land is soldered to the adjacent soldering land. Does not cause a bridge.

Further, since the tip of the soldering land is provided at a position distant from the end face of the slit, a bridge is not formed between the soldering land and an adjacent soldering land, and the solder does not drip into the slit.

Further, since the shape of the soldering portion of the soldering land is made narrow by using the resist layer, the tip portion is narrowed, so that the occurrence of a bridge between the adjacent soldering lands is prevented.

[0018]

EXAMPLES Example 1. An embodiment of the present invention will be described below with reference to the drawings. In FIG. 1, the first printed wiring board 1
The second printed wiring board 2 is attached orthogonally to the slit hole 5. 3 is a continuous soldering land on the second printed wiring board 2 side, and 20 is a continuous soldering land on the first printed wiring board 1 side, which is arranged so as to abut against the soldering land 3.

FIG. 2 is a view seen from the arrow C of FIG. As for the land shape of the soldering land 20, the side extending to the slit hole 5 is tapered as shown in the drawing, and the apex thereof is in contact with the end surface of the slit hole 5. Next, the soldering of the lands 3 and 20 will be described. FIG. 3 is a view of the case where appropriate soldering is performed, as seen from the arrow D of FIG. 1. The solder 6 has a shape as shown in the drawing, and the first printed wiring board 1 and the second printed wiring board The connection with the plate 2 is made.

FIG. 4 shows a state in which continuous butted lands are soldered. The soldering iron 100 is used in order from the end. When the left end shows an appropriate amount of soldering, the solder amount is 21 and 22. Such solder blisters occur. or,
If the land with a large amount of solder continues, solder blisters 23 and 24 occur, and if the next 25 and 26 solder blisters occur before the solder blisters 24 cool and solidify, the solder blisters 24,
It is connected to the soldering iron 100 and the solder blister 25 with the molten solder. However, since the length of the parallel portion of the adjacent lands is short by the amount of the land constriction 27, the solder swelling due to the surface tension of the solder is suppressed to be small, and a solder bridge is unlikely to be formed.

On the other hand, FIG. 5 shows a case where the abutting lands are displaced from each other, and the solder swell 14 at the left end if the appropriate amount of solder is applied, but the length of the parallel portion of the adjacent lands due to the land constriction 27. Because of the short structure, even if the solder blisters 32 occur, the solder blisters 33 are suppressed in the adjacent lands, and even if the lands 3 and the adjacent lands 4 are close to each other, it is difficult to induce the solder bridge. Next, FIG. 6 shows the case where the amount of solder is too small. FIG. 7 shows F of FIG.
-F cross section, the shape of the solder at the center of the connecting portion gathers in the center of the land like the solder bulge 34 due to the land constriction 35 and the surface tension of the solder, so the thickness of the center of the land increases and the second print With respect to the direction in which the wiring board 2 falls,
It is formed into a shape that is difficult to break.

Next, as shown in FIG. 8, when excessive soldering is performed when the slit 5a is provided, the area of the copper foil at the land end of the soldering land 20 is extremely limited, so that the sagging of 19 Is hard to progress. In FIG. 2, good landing results were obtained with a land length of 4.5 mm, a radon width length of 2 mm, a land tip angle of 60 °, and a distance between adjacent lands of 2 mm (land pitch 3 mm).

Example 2. FIG. 9 shows an end portion of the soldering land of the first printed wiring board 1. The soldering land 36 of the copper foil does not have a tapered tip portion, and a resist layer 37 formed on the upper side of the soldering land 36. Is tapered as shown in the figure. That is, the soldering land 36
Make sure that the tip of the soldered part of is tapered.
The soldering land 36 has no resist layer,
The resist layer is formed around it. This has the feature that the peel strength of the copper foil does not decrease.

Example 3. 10 shows a soldering land 38 arranged with the end portion of the soldering land separated from the slit hole 5 by a gap 39, and FIG. 11 shows a sectional view of FIG. Even when the amount of solder is excessive, the gap 39 exists, so that the sagging is further suppressed as shown in the figure. Particularly, in the case of manufacturing by flow soldering, when the width of the gap 39 is not more than the distance between the adjacent lands, proper soldering can be obtained.

Actually, the land width is 2 mm, the tip width is 1 mm,
Good soldering results were obtained with a clearance of 0.5 mm and a gap between adjacent lands of 1 mm. When the slit 5a is small, a good soldering result is obtained even when the gap 39 is zero.

Example 4. FIG. 12 shows a butt land 40.
The end is not formed in a taper shape but is formed in an arc shape, and this embodiment also has the same effect due to the land constriction of the end as in the first embodiment.

Example 5. In the above embodiment, the present invention is the first
Although it is applied to the soldering land of the printed wiring board, it may be applied to the soldering land of the second printed wiring board. Further, it may be applied to both the first and second printed wiring boards.

Further, soldering lands having narrowed tips may be alternately provided on both printed wiring boards. For example, the soldering lands whose tip portions are narrowed are the soldering lands of the first printed wiring board 1, 3, 5. ... The second printed wiring board is provided in the second, 2, 4, 6, ...
It may be provided second. Also, 1, 2, 4,
.., and 3, 4, 6, 7, ..., may be combined. That is, it can be applied to any combination.

Example 6. In the above embodiment, the first printed wiring board and the second printed wiring board are orthogonal (angle 90 degrees).
However, the angle may be 60 degrees or 45 degrees instead of 90 degrees. That is, the present invention can be applied to a device in which two printed wiring boards are arranged so that their surfaces intersect. For example, when a memory such as a ROM or a RAM in the main body of the personal computer is added, the child printed wiring board may be attached at an angle of about 45 degrees with respect to the parent printed wiring board. In this case, a connector is usually connected, but the present invention can be applied to soldering. This has the advantage that the space inside the computer, which is limited in height, can be used effectively.

Example 7. In the above embodiment, the first printed wiring board is provided with the slit hole and the second printed wiring board is fitted in the slit hole, but the present invention can be applied to the case where there is no slit hole. That is, you may arrange | position so that one printed wiring board may abut another printed wiring board. That is, not only the cross shape, but also the T-shaped, G-shaped, L-shaped, and the like, the board surfaces of the two printed wiring boards may intersect.

[0031]

As described above, according to the present invention, the width of the portion to be soldered to the soldering land is narrow near the abutting portion of the soldering land, so that the soldering connection can be made. This has the effect of preventing the induction of solder bridge defects when performing, and also suppressing the induction of solder bridge defects due to the positional deviation between lands. Further, even when the amount of solder is too small, it is possible to form a solder shape that is unlikely to break in the tilt direction of the printed wiring board.
Further, even if there is a gap between the wiring boards, there is an effect that the solder dripping can be prevented.

[Brief description of drawings]

FIG. 1 is a perspective view of a printed wiring board according to a first embodiment of the present invention.

FIG. 2 is a plan view of FIG.

FIG. 3 is a side view of FIG. 1 after soldering.

FIG. 4 is a plan view showing the blisters after soldering in FIG. 1.

5 is a plan view showing the blister after soldering in FIG. 1. FIG.

FIG. 6 is a side view in the case where the amount of solder in FIG. 1 is too small.

7 is a sectional view taken along line FF of FIG.

FIG. 8 is a side view showing the dripping of the solder in FIG.

FIG. 9 is a plan view of a printed wiring board according to a second embodiment of the present invention.

FIG. 10 is a plan view of a printed wiring board according to Embodiment 3 of the present invention.

FIG. 11 is a side view showing the dripping of the solder of FIG.

FIG. 12 is a plan view of Embodiment 4 of the present invention.

FIG. 13 is a perspective view of a conventional printed wiring board.

FIG. 14 is a plan view of FIG.

FIG. 15 is a side view of FIG. 13 after soldering.

FIG. 16 is a plan view showing a swell of soldering shown in FIG.

FIG. 17 is a plan view showing the blisters for soldering in FIG. 16.

FIG. 18 is a side view when the amount of solder in FIG. 13 is too small.

19 is a cross-sectional view taken along line EE of FIG.

FIG. 20 is a side view showing the drooping of the soldering of FIG. 13.

[Explanation of symbols]

1 1st printed wiring board 2 2nd printed wiring board 3,4 Soldering land 5 Slit hole 5a Slit 6 Solder 7 Resist layer 8,9,10,11,12,13 Solder blister 14,15,16,17 , 18 Solder blisters 19 Solder drops 20 Soldering lands 21, 22, 23, 24, 25, 26 Solder blisters 27 Land necks 28, 29, 30, 31, 31, 32, 33, 34 Solder blisters 35 Land necks 36 Soldering lands 37 Resist layer 38 Soldering land 39 Gap 40 Solder blister 100 Soldering iron

[Procedure amendment]

[Submission date] January 11, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0022

[Correction method] Change

[Correction content]

Next, as shown in FIG. 8, when excessive soldering is performed when the slit 5a is provided, the area of the copper foil at the land end of the soldering land 20 is extremely limited, so that the sagging of 19 Is hard to progress. In FIG. 2, good soldering results are obtained with a land length of 4.5 mm, a land width length of 2 mm, a land tip angle of 60 degrees, and a gap between adjacent lands of 2 mm (land pitch: 3 mm).

Claims (4)

[Claims] 1. Two printed wiring boards each having a plurality of soldering lands are arranged such that the soldering lands abut each other, and the abutting soldering lands are connected to each other by soldering. In this configuration, the width of a portion to be soldered to at least one soldering land of the two printed wiring boards is formed so as to be narrow in the vicinity of the abutting portion of the soldering land. And printed wiring circuit device. 2. A slit hole is formed in a first printed wiring board, a second printed wiring board is fitted into this slit hole, and a plurality of soldering lands of both of these printed wiring boards project from each other. In a printed wiring circuit which is arranged so as to be aligned with each other and solders the abutted soldering lands to each other, the tip of the soldering land of the first printed wiring board is separated from the end surface of the slit hole. The printed wiring circuit is characterized in that the width of the portion to be soldered to the soldering land of the first printed wiring board is narrowed near the abutting portion of the soldering land. apparatus. 3. The printed wiring circuit device according to claim 1, wherein the width of the soldering land is narrowed in the vicinity of the abutting portion of the soldering land. 4. The resist layer is formed on the soldering land so that a portion to be soldered in the vicinity of the abutting portion of the soldering land is narrowed. The printed wiring circuit device according to.