JPH0276287A - Printed wiring board - Google Patents

Abstract

PURPOSE:To allow a cut slit to be short-circuited securely and prevent improper soldering at the cut slit part by providing a hole for inserting a lead leg of electronic component or a pin-shaped lead wire at the cut slit. CONSTITUTION:A printed wiring board 11 is provided with a soldering land 15 with a cut slit 16 at a specified wiring pattern 13. This cut slit 16 allows the soldering land 15 to be separated into lands 15a, 15a, thus cutting the wiring pattern 13. Also, a pin-shaped lead wire 19 is inserted into a parts insertion hole 18 on the printed wiring board 11 from the fitting surface on the side of the main unit of electronic circuit component. Then, by performing soldering while the pin-shaped lead wire 19 is being inserted through the hole 18 for inserting components, soldering protuberance adhered to each land 15a, 15b separated by the cutting slit 16 positively constitutes bridges through the pin- shaped lead wire 19. It prevents improper soldering of the cut slit 16.

Description

Detailed Description of the Invention [Object of the Invention] (Industrial Field of Application) The present invention provides a printed wiring board in which cutting slits for circuit testing are formed on predetermined soldering lands. This article relates to a printed wiring board in which lands can be reliably soldered.

(Prior Art) In recent years, in the manufacturing process of printed wiring boards for electronic devices, circuit blocks for each function are mounted on one main printed wiring board to simplify assembly work.

However, if most of the circuits of a device are mounted on the main printed wiring board in this way, even if only one circuit block is defective, all circuit blocks on the main printed wiring board will be energized and the defect will be detected during the inspection process. The location must be discovered. Furthermore, if power is supplied to all circuit blocks, it is often difficult to find defective locations.

Therefore, in conventional printed wiring boards, soldering lands with cutting slits are provided here and there in the wiring pattern.
For this soldering, the cutting slits of the lands are usually short-circuited with solder, and if a defect is found in the board during the inspection process, the solder shorting the cutting slits is removed so that each circuit block can be checked. I have to.

That is, FIG. 6 is an explanatory diagram of a conventional printed wiring board. This printed wiring board 1 includes electronic circuit components with lead legs 2.2...
・Align the main body side of the lead leg 2a to one side, and insert the component insertion hole (not shown) into the side to be used.

2a... is prominent. Then, on the other side, a wiring pattern 3 made of a copper foil conductor is formed. The wiring pattern 3 is covered with a solder resist 4, but the lead legs 2a,
The protruding periphery of 2a... is provided with soldering lands 5, 5... that are not covered with the solder resist 4. Of these soldering lands 5, 5, the soldering land 5 shown within 1 circle P has a cutting slit 6 that partially cuts the wiring pattern 3, as shown in FIGS. 7 and 8. 7 is a plan view of the printed wiring board 1 shown in FIG. 6 as viewed from the wiring pattern side, and FIG. 8 is a plan view of the inside of the circle in FIG. 6. In this way, the soldering land 5 having the cutting slit 6 is a land 5a which is separated by the cutting slit 6 at the -C portion.

5a.

For soldering with such a cutting slit 6, the land 5 is soldered by a flow soldering method, for example,
As shown in FIG. 9, the land 5a.

58 is short-circuited with solder 7.

If the board is defective, the solder at the cutting slit 6 is removed and each circuit block is checked. Having such a cutting slit 6 makes it possible to check the circuit without forcibly cutting the wiring pattern 3, making it extremely convenient, for example, during repair.

However, recently, as shown in FIG. 10, a defect has frequently occurred in which the solder 7 does not reliably short-circuit the cutting slit 6.

The reason for this kind of soldering failure is that the area of the soldering land 5 becomes narrow due to high density soldering, and the solder is only deposited flatly on the soldering land 5, which reliably shorts the cutting slit 6. The reason for this is that it is not possible to secure a sufficient amount of solder.

For example, in the flow soldering shown in FIG. 11, by moving the printed wiring board 1 in the direction of the arrow, the semi-solid solution 8 is soldered to the lands 5, 5, .
..., but the soldering is done on land 5.
If the area of the solder is small and the cutting slit 6 is provided in the center, the solder 7 may be separated into the soldering lands 5a, 5a, as shown in FIG. 12(a). As shown in FIG. 12(b), one land has a large amount of solder, but the other land has less, resulting in poor soldering.

This means that when the printed wiring board 1 separates from the solder melting surface during flow soldering, the soldering surface with the cutting slit 6 is soldered at the land 5, and the solder cutting angle α (
(see FIG. 11) is small.

Furthermore, if the length direction of the cutting slit 6 coincides with the moving direction of the printed wiring board 1 or is perpendicular to the direction of movement of the printed wiring board 1, defects as shown in Fig. 12 will occur due to the solder cutting angle α. .

In order to prevent defects in such soldering, it is conceivable to reduce the width of the cutting slit 6.

However, if the size is reduced beyond a certain limit, it becomes difficult to remove the solder.

In addition, it is possible to consider the direction of the cutting slit 6 in consideration of the direction of movement during soldering so that the flow of solder does not match the direction of the cutting slit 6 or be at right angles to the direction of the cutting slit 6. Since chip components are soldered on the surface of the board 1, it is difficult to uniformly flow the solder to the lands in all soldering operations.

(Problem to be Solved by the Invention) With the recent high-density mounting technology, the area of the soldering land 5 has become smaller, and the cutting slit 6 can be reliably short-circuited by the solder. There is a tendency for the probability of being For this reason, when checking the circuit of printed wiring board 1 after soldering, it is necessary to check whether or not the lands 5 are securely soldered in the case of soldering with cutting slits 6.

Furthermore, when a soldering defect is discovered, it must be corrected manually, which is time consuming and also causes defects, resulting in a decline in both quality and cost.

The object of the present invention is to eliminate the above-mentioned problems, to provide a printed wiring board in which the cutting slits are reliably short-circuited, and the soldering of the cutting slit portions does not require inspection for defects.

[Structure of the Invention (Means for Solving the Problems)] The present invention provides a printed wiring board in which a soldering land is provided with a cutting slit for forming a portion of a wiring pattern, and a lead leg of an electronic component is provided in the cutting slit.

Alternatively, it is characterized by providing a hole into which a bottle-shaped lead wire is inserted.

(Function) When a printed wiring board with such a configuration is soldered with, for example, a pin-shaped lead wire inserted into the component insertion hole, the soldering effect is the same as when soldering the lead legs of ordinary electronic components. is the condition, and the solder mounds attached to the lands separated by the cutting slits reliably form a bridge via the bottle-shaped lead wires. This prevents defective soldering of the cutting slit.

(Example) The present invention will be explained below with reference to illustrated embodiments.

FIG. 1 is a plan view showing an embodiment of a printed wiring board according to the present invention.

In FIG. 1, reference numeral 11 indicates a printed wiring board according to the present invention. This printed wiring board 11 is provided with a soldering land 15 having a cutting slit 16 in a predetermined wiring pattern 13 . The cutting slit 16 divides the soldering land 15 into lands 15a and 15a, thereby dividing the wiring pattern 13. In this embodiment, a component insertion hole 18 is formed in the center of the cutting slit 16 and in the center of the soldering land 15.

In the printed wiring board 11 having the above structure, as shown in FIG. 2, the bottle-shaped lead wire 19 is inserted into the component insertion hole 18 from the mounting surface of the electronic circuit component on the main body side. In this case, the bottle-shaped lead wire 19 is made of a rod-shaped metal wire cut to a predetermined length.
The part protruding from the mounting surface on the main body side is crushed to prevent the handle from falling out of the component insertion hole 18.

Next, the printed wiring board 11 of FIG. 2 is soldered by flow soldering as shown in FIG. 3. According to FIG. 3, since the bottle-shaped lead wire 19 exists in the land 15 of the soldering having the cutting slit 16, the flow of the semi-solid solution 20 is dammed up by this. For this reason,
The solder break angle α in the solder land 15 in the case of FIG. 3 is larger than the solder break angle in the case of FIG. As a result, the amount of solder on each land 15a increases, and the solder adheres to the bottle-shaped lead wire 19 reliably. In this way, like the lead leg portions of other electronic components, a bridge is formed via the bottle-shaped lead wire 19, as shown in FIG.

Correct soldering will form a structure as shown in FIG.

The effect of such soldering is that the diameter of the component insertion hole 18, that is, the bottle-shaped lead wire 19, is smaller than the width of the cutting slit 16.
This can be improved by increasing the diameter of the

Therefore, according to the printed wiring board to which the present invention is applied, it is not necessary to check the soldering of the lands when soldering has the cutting slits 16. Also, inspection of the board.

In the case of repair, the solder on the cutting slit 16 can be easily removed by simply handling the bottle-shaped lead wire 19, allowing conventional inspection and repair to be performed. When inspection and repair are completed, the bottle-shaped lead wire 19 may be inserted into the component insertion hole 18 again and soldered.

Further, according to the present invention, the direction of the cutting slit can be freely determined, and the soldering may be performed using a hollow gold R conductor, a conductor pin used in a connector, or a connector type.

[Effects of the Invention] As explained above, according to the present invention, the soldering of the cutting slit is ensured, an inspection process for this is unnecessary, and there is an effect of providing a high-quality, fixed-cost printed wiring board.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing an embodiment of a printed wiring board according to the present invention, FIG. 2 is an explanatory diagram illustrating the soldering state of the embodiment shown in FIG. FIGS. 4 and 5 are explanatory diagrams explaining the soldering process according to the present invention. FIG. 6 is a side view showing a conventional printed wiring board, and FIG. 7 is a diagram showing the cutting slit. 8 is an explanatory diagram illustrating the cross-sectional state of FIG. 7, FIGS. 9 and 10 are plan views showing the conventional soldering state, and FIG. 11 is a plan view showing the conventional soldering state. 12 is an explanatory diagram for explaining the soldering method of FIG. 11, and the soldering method shown in FIG. 11...Printed wiring board, 13...Wiring pattern, 14
... Solder resistor, 15 ... Soldering is land, 16
... Cutting slit, 18 ... Component insertion hole, 19
...Bottle-shaped lead wire. Figure 1 Figure 2 Figure 3 Figure 5 Figure 10 Figure 11 (a)
(b) Figure 12

Claims (1)

[Scope of Claims] A printed wiring board in which a soldering land is provided with a cutting slit that bisects a wiring pattern, wherein the cutting slit is provided with a hole into which a lead leg of an electronic component or a pin-shaped lead wire is inserted. Characteristic printed wiring board.