JPH0779057A - Circuit board - Google Patents

Abstract

PURPOSE:To obviate the process to turn a board when mounting jumper wires on a board to cut down the manufacture cost by extending the land on the wire insertion side to the jumper end climping side. CONSTITUTION:This board is provided with the first through hole 23 where the land 22 to connect with a wiring pattern 28 on surface side is exposed in the vicinity of its opening on surface side. This is further provided with the second through hole 25 where the land 24 to connect with a wiring pattern 29 on the rear side is exposed in the vicinity of its opening on rear side. Next, each end of a jumper wire 27 is inserted into the first through hole 23 and the second through hole 25 respectively and then bent to form a center 27a and bent part 27b and 27c, and the tip of the turn 27c is positioned below the second land 24b. Next, cream solders 30 and 31 are applied to cover the openings of the first and second through holes 23 and 25 from the surface side of the board 26 so as to solder them by reflow. At this time, the cream solder 30 melts to connect the land 22 with the wire 27, and the cream solder 31 melts to flow to its rear side, along the wire 27, and enters between the bent part 27c and the land 24b so as to connect the land 24 with the wire 27.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit board having a base member having wiring patterns electrically connected by jumper wires on its front and back surfaces.

[0002]

2. Description of the Related Art As electronic devices have become multifunctional in recent years, each wiring pattern formed on the front and back surfaces of a circuit board has been densified.

Such wiring patterns may be connected to each other by jumper wires inserted through the circuit board.

Conventionally, a circuit board having this type of wiring pattern and jumper wires is constructed as shown in FIG.

This will be described with reference to FIG. 1. In FIG. 1, the circuit board indicated by reference numeral 1 has a first through hole 3 in which a land 2 is exposed at the peripheral edge of the front side and a land 4 in which a land 4 is exposed at the peripheral edge of the back side. The base member 6 has two through holes 5, and the jumper wire 7 soldered to both lands 2 and 4 of the base member 6 and inserted through the through holes 3 and 5 and folded back. .

Further, reference numerals 8 and 9 in the figure denote each land 2, respectively.
4 is a solder (cream solder) for electrically connecting the jumper wire 7 to the wire 4.

The base members 6 are provided on both lands 2 and 4, respectively.
Wiring patterns 10 formed on one side surface and the other side surface,
11 is connected.

The front side opening peripheral edge and the back side opening peripheral edge of each through-hole 3, 5 have jumper wires 7 for the base member 6.
In the mounted state, they are located on the wire central portion 7a side and the wire folded portions 7b and 7c side, respectively.

In the circuit board 1 thus constructed, in order to mount the jumper wires 7 on the lands 2 and 4 of the base member 6 by soldering, the respective ends of the jumper wires 7 are connected to the first through holes 3 and the second through holes 3. It is inserted through the through-hole 5 and folded back, and then the cream solder 8 is applied to the land 2 as shown in FIG. 4 (A), after which the base member 6 is inverted as shown in FIG. 4 (B). The solder paste 9 is applied to the land 4, and the base member 6 is housed in a reflow oven (not shown).

[0010]

By the way, in this type of circuit board, the solder 8, 9 for each land 2, 4 is used.
Since the coating is applied from each pattern side of the base member 6, it is necessary to include a step of reversing the base member 6 in manufacturing the circuit board 1. As a result, there is a problem in that the number of manufacturing steps increases and the cost increases.

The present invention has been made in view of the above circumstances, and the step of inverting the base member at the time of manufacturing the board can be eliminated, and thus the manufacturing cost can be reduced. Is provided.

[0012]

A circuit board according to the present invention has a land exposed on the front opening edge of the first through hole and a land on the wire insertion side of lands exposed on the back opening edge of the second through hole. The jumper wire is extended on the folded side.

[0013]

In the present invention, when the reflow soldering is performed, the first
The applied solder on the peripheral edge of the front side opening of the through hole and the second through hole is melted, and the molten solder on one side of the molten solder connects the land and the jumper wire exposed on the peripheral edge of the front side opening of the second through hole. At the same time, the jumper wire is connected to the land including the extending portion exposed at the back side opening peripheral edge of the second through hole by the molten solder on the other side flowing along the jumper wire passing through the second through hole.

[0014]

Embodiments of the present invention will be described in detail below with reference to embodiments shown in the drawings.

1A and 1B are a vertical sectional view and a bottom view showing a circuit board according to the present invention.

In FIG. 1, reference numeral 21 denotes a circuit board used in, for example, a 3.5-inch micro-floppy disk device, which has a first through hole (hereinafter, referred to as "first bare hole") in which a land 22 is exposed at a peripheral edge of a front side opening. ".")
23 and a base member 26 having a second through hole (hereinafter, referred to as “second bare hole”) 25 in which the land 24 is exposed at the periphery of the back side opening, and both lands 22, 2 of the base member 26.
4 is soldered and mounted on both of the bare holes 23 and 25.
And a jumper wire 27 formed by folding back.

On the base member 26 of the circuit board 21, a wiring pattern 28 on the front surface side and a wiring pattern 29 on the back surface side which are respectively connected to the lands 22 and 24 are formed.

On the other hand, the jumper wires 27 of the circuit board 21 are respectively positioned on the front side opening peripheral edge side of the first bare hole 23 and the back side opening peripheral edge side of the second bare hole 25 in a wire mounted state on the base member 6. A wire central portion 27a and wire folding portions 27b and 27c are provided.

Now, both lands 2 on this circuit board 21
The land 24 on the jumper wire insertion side of 2, 24 is
An annular first land portion 24a exposed at the back side opening peripheral edge of the second bare hole 25 and a wire folding portion (tip) side of the jumper wire 27 extending to the first land portion 24a so that the land width becomes closer to the tip. It is configured by the smaller second land portion 24b.

The tip of the second land portion 24b of the land 24 is formed in an arc shape, and the distance from the tip of the arc portion to the center of the second through hole 25 is set to 1.75 mm. There is.

The outer diameters of the first land portion 24a of the land 24 and the land 22 are set to 2.0 mm.

The diameters of the first bare hole 23 and the second bare hole 25 are set to 1.0 mm, and the outer diameter of the jumper wire 27 is 0.6 mm.
Has been set to the dimensions of.

Reference numerals 30 and 31 in the drawing are cream solders for electrically connecting the jumper wires 27 to the lands 22 and 24.

Next, the procedure for manufacturing the circuit board in this embodiment will be described with reference to FIGS.

First, as shown in FIG.
The wiring pattern 28 on the front side and the wiring pattern 2 on the back side
9 is formed, and both wiring patterns 28 and 29 are formed.
Of the land 22 connected to the wiring pattern 28 on the front surface side
The first bare hole 22 exposed at the peripheral edge of the front opening and the second bare hole 25 exposed at the peripheral edge of the rear opening of the land 24 connected to the wiring pattern 29 on the rear surface side are provided.

Next, as shown in FIG. 3B, the wire ends of the jumper wire 27 are connected to the first bare hole 23 and the second bare hole 23, respectively.
The wire central portion 27a and the wire folded portions 27b and 27c are formed by inserting the wire into the bare hole 25 and folding it back.

At this time, both wire folding portions 27b, 2
Of the wire 7c, the tip of the wire return portion 27c has a land 2
4 is located below the second land portion 24b.

Thereafter, as shown in FIG. 3C, the cream solder 3 is applied to the base member 26 from the surface side (land 22 side).
0 and 31 are applied so as to cover the openings of the first bare hole 23 and the second bare hole 25.

Then, as shown in FIG. 7D, the jumper wire 27 is soldered to the lands 22 and 24 by accommodating the base member 26 with the jumper wire in a reflow furnace (not shown).

At this time, the cream solder 30 is melted to connect the land 22 and the jumper wire 27, and the cream solder 31 is melted and inserted into the second bare hole 25. The base member 26 is inserted along the heated jumper wire 27. Flows from the front surface side to the back surface side, enters between the wire folded portion 27c and the second land portion 24b, and connects the land 24 and the jumper wire 27.

That is, the jumper wires 27 are connected to the lands 22 and 24 on each side by applying the cream solders 30 and 31 to only one side surface of the base member 26.

In this way, the circuit board 21 in this embodiment can be manufactured.

Therefore, in this embodiment, the step of reversing the base member 26, which is conventionally required when manufacturing a substrate (solder application), is not required, and the number of manufacturing steps can be reduced.

In this embodiment, an example in which it is applied to a circuit board of a 3.5-inch micro-floppy disk device has been shown, but the present invention is not limited to this, and a circuit board of other electronic equipment. The same can be applied to the embodiment.

Further, the shape and external dimensions of the land 24 in the present invention are not particularly limited to those in the above-mentioned embodiment, and can be appropriately changed according to the length and outer diameter of the wire folded portions 27b and 27c of the jumper wire 27. Of course.

[0036]

As described above, according to the present invention, the land on the wire insertion side of the lands exposed on the front opening edge of the first through hole and the land on the wire insertion side of the lands exposed on the back opening edge of the second through hole are jumpered. Since the wire is extended on the turn-back side, the solder applied to the front edge of each of the first through hole and the second through hole is melted at the time of reflow soldering, and one of these molten solders is melted solder. The land and the jumper wire exposed on the front side opening peripheral edge of the first through hole are connected by, and the back side opening peripheral edge of the second through hole is formed by the other side molten solder flowing along the jumper wire inserted through the second through hole. The land including the extended portion exposed to the outside and the jumper wire are connected.

Therefore, the step of reversing the base member, which is conventionally required when manufacturing the circuit board, becomes unnecessary, so that the number of manufacturing steps can be reduced and the cost can be reduced.

[Brief description of drawings]

1A and 1B are a cross-sectional view and a bottom view showing a circuit board according to the present invention.

2A to 2D are cross-sectional views similarly shown for explaining the procedure for manufacturing a circuit board according to the present invention.

3A and 3B are a plan view and a bottom view showing a conventional circuit board.

4A and 4B are cross-sectional views shown for explaining a conventional procedure for manufacturing a circuit board.

[Explanation of symbols]

 21 ... Circuit board 22 ... Land 23 ... 1st bare hole 24 ... Land 24a ... 1st land part 24b ... 2nd land part 25 ... 2nd bare hole 26 ... Base member 27 ... Jumper wire 27a ... Wire center part 27b, 27c ... Wire Folded portion 28, 29 ... Wiring pattern 30, 31 ... Cream solder

Claims (1)

[Claims] 1. A base member having a first through hole in which a land is exposed at a peripheral edge of a front side opening and a second through hole in which a land is exposed at a peripheral edge of a back side opening, and soldering to both lands of the base member and the through holes. A circuit board provided with a jumper wire formed by folding back through a hole, wherein a land on the wire insertion side of the lands extends on the folding back side of the jumper wire.