JPH05266936A - Connecting structure for lead comb and printed board - Google Patents

Abstract

PURPOSE:To prevent electrical improper contact by improving strength of connecting a lead comb to a printed board (child board). CONSTITUTION:A lead comb 4 comprises a U-shaped fitting part, formed of an upper surface part 4a of opening a hole 5, side surface part 4b and a lower surface part 4c, and a connecting part 4d connected to the lower surface part 4c and soldered to a conductor 11 of a parent board 10. A child board 1 is fitted to the U-shaped fitting part of the lead comb 4, and in a condition that the hole 5 is filled with paste-state solder 6, a conductor 2 is soldered to the lead comb 4. A part between an end face of the child board 1 and the lead comb 4 is charged with a conductive bonding agent 7 or insulating bonding agent 8. In the lead comb 4, a length B of the lower surface part 4c is set so as to be two times or more the length A of the upper surface part 4a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in electronic equipment, and is a lead comb for joining a lead comb to a printed board which is a child board in order to mount a printed board such as a hybrid circuit board as a child board on a parent board. And a printed circuit board joint structure.

[0002]

2. Description of the Related Art Conventionally, there is a method of using a comb terminal as a typical example of a method for connecting a child board and a parent board.
In this method, the lead comb terminal of the child board on which the surface-mounted component is mounted is inserted into the hole of the parent board in the form of lead through and mounted. Among them, the child board having a plurality of rows of terminals does not fall down like the child board having one row of terminals. In addition, a plurality of components are surface-mounted on a child board and a plurality of components are arranged, or a plurality of components are stacked and used.

FIG. 5 shows a conventional joint structure between a lead comb and a printed circuit board. In FIG. 5, 21 is a parent board, 22 is a conductor formed on the parent board 21, 23 is a lead comb, 24,
28 and 29 are solders, 25 is a sub-board, 26 is a sub-board 25
, A chip part, 30 is a hole for inserting the lead comb 23, and 31 is a void. This conventional lead comb and printed circuit board joint structure is often used in a hybrid circuit board without resin molding.
The conductor 26 is formed and the chip component 27 is soldered. Further, the child board 25 is fitted between the upper terminal 23a and the lower terminal 23b of the lead comb 23 (fitting portion), and the conductor 26 and the upper terminal 23a are manually joined with the solder 29. This is because it is difficult to apply the generalized methods of dip soldering and reflow soldering to the lead comb section. And Leadcom 2
3 is inserted into the hole 30 of the parent board 21, and the conductor 2 of the parent board 21 is inserted.
It is joined to 2 with solder 24.

[0004]

However, according to the above-mentioned conventional structure, in the fitting portions (23a, 23b),
Due to shock during transportation or after storage of equipment, the upper terminal 23
In many cases, the spring property of a and the lower terminal 23b was deteriorated, and poor contact between the soldered upper terminal 23a and the conductor 26 was caused.

Further, the end face of the child board 25 and the lead comb 2
3 is not fixedly connected, has no adhesive strength, and has a void 31. This is because the end surface of the child board 25 becomes a rough surface due to processing such as punching, shearing, and routing. Therefore, the end surface of the child board 25 and the lead comb 2 are formed.
That is, a gap is created between the two and 3. Even if the end surface of the child substrate 25 is plated, voids and blisters are generated, the adhesiveness between the plating layer and the end surface tends to be brittle, and an uneconomical thickness is only required.

In order to increase the adhesive strength between the child board 25 and the lead comb 23, the lower terminal 23b is attached to the child board 25.
When soldered to the upper terminal 23 due to the heating environment
The solder joint of a is loosened. An object of the present invention is to provide a joint structure between a lead comb and a printed circuit board, which can improve the joint strength between the lead comb and the printed circuit board (child board) and prevent electrical contact failure.

[0007]

According to a first aspect of the present invention, there is provided a joining structure of a lead comb and a printed circuit board, wherein a pair of lead combs each having a U-shaped fitting portion including an upper surface portion, a side surface portion and a lower surface portion are used. The lead comb's mating parts are fitted to the opposite ends of the printed circuit board, and the adhesive is filled between the printed circuit board end and the side surface of the lead comb. At least one of the parts is soldered to the conductor of the printed circuit board.

According to a second aspect of the present invention, there is provided a joint structure between a lead comb and a printed circuit board, wherein in the joint structure between the lead comb and the printed circuit board according to the first aspect, a hole is provided in at least one of an upper surface portion and a lower surface portion of the lead comb. It is characterized in that the paste-like solder stored in the hole is diffused between the conductor and at least one of the upper surface portion and the lower surface portion where the hole is provided for soldering.

According to a third aspect of the present invention, there is provided a joint structure between a lead comb and a printed circuit board, wherein the length of the lower surface of the lead comb is twice as long as that of the upper surface. The above is characterized.

[0010]

According to the structure of the present invention, the U-shaped fitting portions of the pair of lead combs are fitted to the opposite end portions of the printed circuit board, and the end portions of the printed circuit board and the side surface portions of the lead comb are connected. By filling an adhesive between the lead combs and solder-bonding at least one of the upper surface and the lower surface of the lead comb to the conductor of the printed circuit board, the bonding strength between the lead comb and the printed circuit board is improved, and Electrical contact failure can be prevented.

A hole is provided in at least one of the upper surface and the lower surface of the lead comb, and the paste-like solder stored in the hole is diffused between the conductor and at least one of the upper surface and the lower surface provided with the hole. By performing the solder bonding, the bonding strength between the lead comb and the printed board is further improved, and the electrical contact failure between the conductor and the lead comb can be further prevented.

Further, by making the length of the lower surface of the lead comb more than twice the length of the upper surface, the contact distance between the lead comb and the lower surface of the printed circuit board can be effectively lengthened and vibration durability can be improved. It is possible to increase the number, and it is possible to further prevent poor electrical contact between the conductor and the lead comb.

[0013]

【Example】

[First Embodiment] A first embodiment of the present invention will be described with reference to FIG. FIG. 1 (a) is a sectional view showing a joint structure between a lead comb and a printed circuit board according to the first embodiment of the present invention.
FIG. 1B is a plan view of the child board in FIG. In FIG. 1, 1 is a child board (printed board), 2 is a conductor formed on the child board 1, 3 is a component joined to the conductor 2 with solder 9, 4 is a lead comb, 5 is a hole for injecting solder 6, 7 is a conductive adhesive, 8 is an insulating adhesive, 10 is a parent substrate, 11
Is a conductor formed on the parent substrate 10, and 12 is solder.

The sub-board 1 is made of, for example, paper phenol, paper epoxy, glass cloth epoxy, aramide non-woven cloth epoxy, glass, ceramic or the like, and conductors 2 are formed on both sides (or one side) as XY planes. Conductor 2
Is formed of copper foil, copper plating, silver / palladium paste, copper paste, or the like, and multi-layer plating of nickel, gold, silver or the like, or through-hole plating can also be adopted. Part 3
Are chip capacitors, molded transistors, flat pack ICs, chip coils, and the like. The child board 1
The end surface of the is an irregular surface due to the protrusion of glass fibers and the obstacle to dissolution in the plating bath.

The lead comb 4 has an upper surface 4 having a hole 5 formed therein.
a, a U-shaped fitting portion composed of the side surface portion 4b and the lower surface portion 4c, and a connection connecting portion 4d connected to the lower surface portion 4c and soldered to the conductor 11 of the parent board 10. Lead com 4
In order to bond the child board 1 and the child board 1, a conductive adhesive 7 or an insulating adhesive 8 is applied to the end surface of the child board 1 in advance.
The sub-board 1 is fitted into the fitting portions (4a, 4b, 4c) of the two lead combs 4, and the conductor 5 and the lead comb 4 are reflowed in a state where the holes 5 of the upper surface portion 4a are filled with the paste-like solder 6. Solder. At this time, the solder 6 spreads between the conductor 2 and the upper surface portion 4a of the lead comb 4 by the creep action to form a wide area joint portion. After that, the conductive adhesive 7 or the insulating adhesive 8 is cured and fixed at 150 ° C. or lower.

Further, the lead comb 4 fitted with the child board 1
The connection between the parent board 10 and the parent board 10 is made by connecting the connecting portion 4 of the lead comb 4.
d is inserted into the hole 13 of the parent substrate 10, and the tip end is connected to the conductor 11 with the solder 12. As described above, according to this embodiment, when the lead comb 4 and the child board 1 are joined, the child board 1 is fitted in the U-shaped fitting portion of the lead comb 4, and the end face of the child board 1 and the lead comb 1 are joined together. 4 is filled with a conductive adhesive 7 or an insulating adhesive 8, so that the bonding strength between the lead comb 4 and the child board 1 is increased and the electrical contact between the conductor 2 and the lead comb 4 is poor. In addition, it is possible to prevent foreign matter from entering between the end surface of the child board 1 and the lead comb 4.

Further, by reflow soldering the conductor 2 and the lead comb 4 with the holes 5 filled with the paste-like solder 6, the solder joint area is increased. Therefore, the bonding strength is further increased, and the electrical contact failure between the conductor 2 and the lead comb 4 can be further prevented. The solder joint area is 10 times or more the joint area when the peripheral portion of the electrode is surrounded by solder, which is a conventional technique, and therefore the joint strength is 10 times or more. The shape of the hole 5 may be circular, square, or cut, and the cross-sectional shape may be mortar-like to change the fluidity of the paste-like solder 6.

The lead comb 4 is set so that the length B of the lower surface 4c is at least twice the length A of the upper surface 4a. This means that if the length B is less than twice the length A,
The vibration transmitted from the lower part of the child board 1 makes it easier to loosen the fitting between the lead comb 4 and the child board 1. However, by setting the length B to be at least twice the length A, the lead comb 4 and the child board 1 can be loosened. It is possible to effectively lengthen the contact distance between the lower surface of No. 1 and the lower surface and increase the vibration durability.

In this embodiment, the lower surface portion 4c of the lead comb 4 is not soldered to the child board 1, but like the upper surface portion 4a, a hole is formed in the lower surface portion 4c to form a lower surface of the child board 1. The conductor 2 may be soldered. At this time, the upper surface portion 4a and the lower surface portion 4c can be simultaneously solder reflow bonded. [Second, Third, and Fourth Embodiments] A second embodiment of the present invention is shown in FIG. 2, a third embodiment is shown in FIG. 3, and a fourth embodiment is shown in FIG.
Shown in. 2 to 4, parts corresponding to those in FIG. 1 are designated by the same reference numerals. The parent board is not shown.

The lead combs and the printed circuit boards shown in FIGS.
1 is different from the embodiment shown in FIG. 1 in that the connecting method with the parent board is a surface mounting type, and other configurations are the same as those in the embodiment shown in FIG. In the embodiment shown in FIG. 2, the lead comb 14 is bent in two steps at an angle of 90.degree.

In the embodiment shown in FIG. 3, the lead comb 15 is bent by 180 ° on the lower surface of the child board 1 to shorten the distance between the child board 1 and the parent board (not shown). In the embodiment shown in FIG. 4, the lead comb 16 is bent in four steps at an angle of 45 ° from the lower surface portion or the connecting / connecting portion,
Elasticity is given to mechanically float the child board 1 from a parent board (not shown).

In each of the embodiments shown in FIGS.
As a matter of course, the same effect as the embodiment of FIG. 1 is obtained.

[0023]

According to the joint structure of the lead comb and the printed circuit board of the present invention, the U-shaped fitting portions of the pair of lead combs are fitted to the opposite end portions of the printed circuit board, respectively. By filling an adhesive between the side surface of the lead comb and the side surface of the lead comb, and soldering at least one of the upper surface and the lower surface of the lead comb to the conductor of the printed circuit board,
The bonding strength between the lead comb and the printed circuit board is improved, and the electrical contact failure between the conductor and the lead comb can be prevented, and foreign matter is prevented from entering between the printed circuit board and the mating part of the lead comb. can do.

A hole is provided in at least one of the upper surface and the lower surface of the lead comb, and the paste-like solder stored in the hole is diffused between the conductor and at least one of the upper surface and the lower surface provided with the hole. By performing the solder bonding, the bonding strength between the lead comb and the printed board is further improved, and the electrical contact failure between the conductor and the lead comb can be further prevented.

Further, by making the length of the lower surface of the lead comb more than twice the length of the upper surface, the contact distance between the lead comb and the lower surface of the printed circuit board is effectively lengthened, and vibration durability is improved. It is possible to increase the number, and it is possible to further prevent poor electrical contact between the conductor and the lead comb.

[Brief description of drawings]

1A is a sectional view showing a joint structure between a lead comb and a printed circuit board according to a first embodiment of the present invention, and FIG. 1B is a plan view of a daughter board in FIG. 1A.

FIG. 2 is a sectional view showing a joint structure between a lead comb and a printed circuit board according to a second embodiment of the present invention.

FIG. 3 is a cross-sectional view showing a joint structure between a lead comb and a printed board according to a third embodiment of the present invention.

FIG. 4 is a sectional view showing a joint structure between a lead comb and a printed circuit board according to a fourth embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a conventional joint structure between a lead comb and a printed circuit board.

[Explanation of symbols]

 1 Substrate (printed circuit board) 2 Conductor 4,14,15,16 Lead comb 4a Upper surface part 4b Side surface part 4c Lower surface part 5 Hole 6 Solder 7 Conductive adhesive 8 Insulating adhesive A Upper surface length B Lower surface part Length of

Claims (3)

[Claims] 1. A pair of lead combs each having a U-shaped fitting portion including an upper surface portion, a side surface portion, and a lower surface portion are used, and the fitting portions of the pair of lead combs are fitted to opposite end portions of a printed circuit board. And a lead obtained by filling an adhesive between the end portion of the printed circuit board and the side surface portion of the lead comb and solder-bonding at least one of the upper surface portion and the lower surface portion of the lead comb to the conductor of the printed circuit board. Bonding structure of comb and printed circuit board. 2. A lead comb is provided with a hole in at least one of an upper surface portion and a lower surface portion, and paste-like solder stored in the hole is provided between the conductor and at least one of the upper surface portion and the lower surface portion provided with the hole. The lead comb and printed circuit board joining structure according to claim 1, wherein the lead comb and the printed circuit board are soldered by being diffused into the substrate. 3. The joint structure of a lead comb and a printed circuit board according to claim 1, wherein the length of the lower surface of the lead comb is at least twice the length of the upper surface.