JPH04788A - Pattern shape of printed circuit board - Google Patents

Abstract

PURPOSE:To improve solder absorbing effect, to roughen a check pin mounting accuracy of a board checker and to easily manufacture the checker by increas ing the area of part of a plurality of land patterns disposed in close contact larger than the other land pattern. CONSTITUTION:Land patterns 5, 6 are increased in area larger than the other land patterns 2, 3, 4, 7, 8, 9. The patterns 5, 6 are increased larger than the others. Thus, if a solder iron is moved from above to below by a manual opera tion, or if a solder layer is caulked from above to below, excessive solder can be absorbed by the patterns 5, 6, thereby alleviating a solder bridge generation between lands. Its absorbing effect is larger than so-called sacrificing pattern, and a check pin mounting accuracy can be roughened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pattern shape of a printed wiring board.

[Conventional technology]

In conventional printed wiring boards, a pattern called a sacrificial pattern is placed near a plurality of densely arranged land patterns, and the sacrificial pattern absorbs excess solder to prevent solder bridges from occurring during component mounting. There are known methods to reduce this.

[Problem to be solved by the invention]

However, the above-mentioned disposable pattern used in the conventional method is isolated and insulated from other patterns including the land pattern, so the effect of absorbing excess solder is
In the case of manual soldering, there is some effect, but in the case of automatic soldering tank or flow soldering tank, there is an extra process of licking the solder at the end, but the effect is not as expected. There was a point. Due to the movement of the soldering iron or the final licking process of the solder bath, the excess solder adhering to each land pattern is sequentially moved from one land pattern to another, and is finally absorbed by the above-mentioned discard pattern.
This is because the last discarded pattern is difficult to move because it is insulated and isolated from other patterns.

In addition, creating a separate discarded pattern requires a lot of time and effort when designing a pattern, especially when components are mounted at a high density and the patterns are crowded together. There was a problem in that it required

The present invention aims to solve the above problems. In other words, the present invention has a greater solder absorption effect than the conventional discarded pattern, and also makes it possible to roughen the check pin attachment accuracy of the board checker, making it easier to manufacture the checker, thereby making it possible to improve the quality of printed wiring boards for a while. The purpose is to provide a pattern shape.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides land patterns of a printed wiring board in which a plurality of land patterns are densely arranged.
It is assumed that some of the land patterns have a larger area than other land patterns.

[For production]

According to the present invention, some of the land patterns among the densely arranged land patterns have a larger area than the other land patterns, so the large area of the land pattern absorbs excess solder. It is possible to ensure this and save time and effort when designing a printed wiring board. In addition, in order to check for defects in a printed wiring board, it is necessary to bring a check pin attached to a checker, which is an inspection tool, into contact with a pattern to be checked for continuity. Naturally, the larger the pattern to be brought into contact, the rougher the check pin mounting accuracy is required, and by making some land patterns larger than most land patterns, there is also the effect of making it easier to create checkers.

〔Example〕

FIG. 1 shows a first embodiment of the invention.

That is, the figure shows the pattern of the pudding and the wiring board. Here, it is assumed that eight bins of flat package ICs are mounted, and the ICs are mounted at mounting position 1 indicated by the broken line. 2, 3, 4, 5, 6.
7, 8, and 9 are land patterns for soldering and connecting the electrode bins of the ICs to be mounted, and the land patterns are connected to other land patterns or wiring patterns;
The connection state differs depending on the circuit that implements the pattern, and is not related to the gist of the present invention, so a description thereof will be omitted here.

As shown in FIG. 1, the land pattern 5.6 has a larger area than the other land patterns 2, 3, 4, 7, and 8.9.

In this way, by making the land patterns 5 and 6 larger than the others, if the soldering iron is moved manually from the top to the bottom in the figure, or if the solder bath licking process is performed from the top to the bottom, the excess The land pattern 5.6 can absorb the solder, and the occurrence of solder bridges between the lands can be reduced. Further, as described above, the absorbing effect is greater than that of the conventional so-called throwaway pattern, and the accuracy of the check pin attachment can be made rougher.

FIG. 2 shows a second embodiment of the invention.

In this second embodiment as well, as in FIG. 1, it is assumed that eight bins of flat package ICs are mounted, and the ICs are mounted on the mounting apparatus 10 shown by the broken line.

Also 11.12゜13.14, 15, 16, 17.18
is a land pattern for soldering the electrodes of the IC, and is the same as in the case of FIG.

In FIG. 2, the land pattern 1214.15.1
7 is larger than the others, and the effect of these larger land patterns is that of land patterns 5 and 5 in Figure 1.
This is the same as 6.7, but since the number of larger land patterns has been increased, the solder absorption and checker creation are even easier than in FIG. 1.

FIG. 3 shows an example of the shape of a sharp land pattern. In other words, the shape of the land pattern to be enlarged is
Naturally, it is preferable to use a material that can easily absorb solder, and for this purpose, land patterns 19 and 20 in FIG. 3 can be considered. If the land pattern 19 in FIG. 3 is replaced by the land pattern 12.17 in FIG. 2, and the land pattern 20 in FIG. 3 is replaced by the land pattern 14.15 in FIG. 2, the effect of solder absorption will be increased. . The reason for this is that in manual soldering, the soldering iron is moved from top to bottom with respect to the land pattern shown in FIG. Alternatively, in the licking step in the solder bath, if the licking is performed from top to bottom, excess solder will accumulate in the wide lower part of each of the land patterns 19 and 20.

In the above embodiment, an 8-pin flat package IC is used.
However, it is possible to implement the present invention with respect to parts having other shapes. In addition, many shapes of the land pattern other than the above-mentioned embodiments can be considered. Furthermore, the present invention can be practiced without being limited to the type or material of the printed wiring board.

(Effects of the Invention) As explained above, according to the present invention, some land patterns of a printed wiring board have a larger area than other land patterns, and are isolated from other patterns like a discarded pattern. Because it is not a traditional pattern, it is possible to obtain a greater solder absorption effect than the discarded pattern used in the past, and it is also possible to make the check bin mounting accuracy of the board checker rougher, making it easier to manufacture the checker. effective.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing the first embodiment of the present invention, FIG. 2 is an explanatory diagram also showing the second embodiment, and FIG. 3 is an explanatory diagram showing an example of the shape of an enlarged land pattern. be. 1... Mounting position 2.3.4... Land pattern 5.6... Large area runt pattern 7.8.9.
...Runt pattern 10...Mounting position 11...Land pattern 1
2...Land pattern 13 with large area...Land pattern 14.15...Land pattern 16 with large area...
・Land pattern 17...Runt pattern with large area 18...Land pattern 19.20...Land pattern with large area Figure 1 Figure 2 Figure 3 Other 4 people

Claims (1)

[Scope of Claims] 1. A land pattern of a printed wiring board in which a plurality of land patterns are densely arranged, in which some of the land patterns have a larger area than other land patterns. The pattern shape of the printed wiring board. 2 The area of the land pattern that has a large area is
It absorbs excess solder during component mounting and reduces the installation accuracy of checker contact pins.
2. The pattern shape of a printed wiring board according to claim 1, which has a size that allows either one of them.