JP2003023237A - Printed board device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure reliability of connection between a lead and a wiring pattern by preventing stripping of solder and a land. SOLUTION: A solder coat f is provided to cover the inner circumferential surface at the tubular part a1 of a land a and the upper and lower surfaces at the flange part a2 and solder e for connecting a lead wire L is provided on the inner circumferential surface at the tubular part f1 of the solder coat f and on the upper and lower surfaces at the flange part a2. Since the outside diameter at a projecting part e1 is set smaller than the outside diameter at the flange part f2 on the upper and lower surface sides of the solder coat f, the projecting part e1 of the solder e does not function to raise the flange part f2 thus preventing easy stripping.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed circuit board device, and more particularly to a structure for preventing separation between a land and a wiring pattern.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 3 to 6, in order to solder a lead wire L of an electronic mounting component M such as a resistor and a capacitor to a through hole C of a printed circuit board b using a solder e, Usually, flow soldering is performed with lead-free solder. The electrical connection between the lead wire L and the wiring pattern g on the surface of the printed board b is performed via the solder e. In each drawing, in a conventional printed circuit board device, a land having a cylindrical portion a1 covering the inner peripheral surface of a through hole C provided on a printed circuit board b and a flange portion a2 covering upper and lower surfaces near the through hole. (Copper-eye part) a,
The lead wire L of the electronic mounting component M provided so as to penetrate the cylindrical portion a1 of the land a, and the solder that is welded in the land a and has the protruding portion e1 protruding to the upper and lower surface sides. e and.

In the figure, d is a resist applied on the surface side of the wiring pattern g. Conventionally, the outer periphery of the protruding portion e1 is regulated by the resist d as described above, but the outer periphery of the protruding portion e1 corresponds to the joint a3 between the outer periphery of the flange portion a2 of the land a and the wiring pattern g. It is configured as follows.

[0004]

However, conventionally, immediately after soldering, the outer periphery of the solder protruding portion e1 is separated from the joint a3 as shown in FIG. 5, resulting in poor electrical connection with the wiring pattern g. As shown in FIG. 6, the flange portion a2 is caused to contract due to the contraction of the protruding portion e1.
When it is pulled in one direction, the flange portion a2 and the wiring pattern g are peeled off to generate a peeled portion t, which causes a problem that electrical connection is deteriorated. It is considered that this is because a specific metal element is biased or remains unhardened in a stage where the solder is cooled and hardened immediately after soldering, and the shrinkage of the printed circuit board b occurs at the same time as the shrinkage of the solder. To be

The present invention has been made to solve the above-mentioned problems, and eliminates the electrical connection failure between the solder and the wiring pattern and the electrical connection failure between the land and the wiring pattern, thereby improving reliability. It will increase

[Means for Solving the Problems]

According to a first aspect of the present invention, there is provided a land covering the inner peripheral surface of the through hole provided on the printed circuit board and the upper and lower surfaces in the vicinity of the through hole, and an electronic mounting component provided so as to penetrate the land. Of the lead wire and the solder that is welded in the land and is applied so as to protrude to the upper and lower surface sides, a solder covering the inner peripheral surface and the upper and lower surfaces of the land. A coat is provided, and the solder is applied to the inner peripheral surface of the solder coat and above,
It is arranged on the lower surface.

In the invention according to claim 2, the outer diameters on the upper and lower surface sides of the solder coat are set to be smaller than the outer diameters on the upper and lower surface sides of the land, and the upper and lower surfaces of the solder are set. The outer diameter on the side was set smaller than the outer diameter on the upper and lower surfaces of the solder coat.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiment 1. 1 and 2 are sectional views showing an embodiment of a printed circuit board device according to the present invention, and the same parts as those in FIGS. 3 to 6 are designated by the same reference numerals. In each drawing, in the printed circuit board device, the land a
A solder coat f covering the inner peripheral surface of the cylindrical portion a1 and the upper and lower surfaces of the flange portion a2 is provided, and the solder e is applied to the inner peripheral surface of the cylindrical portion f1 of the solder coat f and the upper and lower portions of the flange portion f2. It was provided on the surface so that the lead wire L was connected. Here, the outer diameter of the flange portion f2 of the solder coat f is set to be smaller than the outer diameter of the flange portion a2 of the land a, and the outer circumference is stepped, and the upper and lower surface sides of the solder e are The outer diameter of the protruding portion e1 is set to be smaller than the outer diameter of the flange portion f2 on the upper and lower surface sides of the solder coat f.

In this case, as a component of the solder coat f, a lead-free solder component (Sn, Ag, Cu) is used.
The resist d is applied for prevention of moisture resistance and insulation, and a rosin-based resin film photosensitive resist is used. After applying the resist d, the solder coat f is applied.
By applying the solder coat f, the solder e and the solder coat f have the same solder component, so that the solderability is improved and the solder joint strength can be increased. Further, heat stress on the copper foil portion of the wiring pattern can be reduced, rust on the copper foil portion can be prevented, and solderability can be improved. According to the above configuration, the protruding portion e of the solder e
Even when 1 tries to shrink, since the solder e and the solder coat f have the same solder component, the bonding strength is high because of good integration, and the outside diameter of the protruding portion e1 is small, so that the protrusion of the solder e The portion e1 does not act to lift the flange portion f2 and does not peel off more easily.

Even if the flange portion f2 tries to contract, the outer periphery of the flange portion f2 is the flange portion a2 of the land a.
Since the outer diameter is smaller than the outer diameter, the force for peeling the flange portion a2 is weak, so that the flange portion a2 is unlikely to be separated from the wiring pattern g. Therefore, the conventional peeling portion does not occur. Therefore, the reliability of the electrical connection between the land a and the wiring pattern g, the electrical connection between the land a and the solder coat f, and the electrical connection between the solder coat f and the solder e can be ensured for a long period of time.

[0011]

As described above, since the solder coat covering the inner peripheral surface and the upper and lower surfaces of the land is provided and the solder is provided on the inner peripheral surface and the upper and lower surfaces of the solder coat, The peeling of the solder and the land can be prevented, and the reliability of electrical connection can be improved.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

FIG. 2 is a sectional view showing a main part of an embodiment of the present invention.

FIG. 3 is a cross-sectional view showing an example of a conventional printed circuit board device.

FIG. 4 is a sectional view showing a main part of an example of a conventional printed circuit board device.

FIG. 5 is a cross-sectional view illustrating a problem of a conventional printed circuit board device.

FIG. 6 is a cross-sectional view illustrating a problem of a conventional printed circuit board device.

[Explanation of symbols]

a land, a1 cylinder part, a2 flange part, b printed circuit board, c through hole, d resist, e solder, e1 protruding part, g wiring pattern, f solder coat, f2 flange part.

Claims (2)

[Claims] 1. A land covering an inner peripheral surface of a through hole provided on a printed circuit board and upper and lower surfaces near the through hole, a lead wire of an electronic mounting component provided so as to penetrate the land, and the land. In a printed circuit board device provided with solder which is welded inside and is applied so as to protrude to the upper and lower surface sides, a solder coat is provided to cover the inner peripheral surface of the land and the upper and lower surfaces, and A printed circuit board device characterized in that the solder coat is adhered to the inner peripheral surface and the upper and lower surfaces. 2. The outer diameters of the upper and lower surface sides of the solder coat are set smaller than the outer diameters of the upper and lower surfaces of the land, and the outer diameters of the upper and lower surface sides of the solder are on the solder coat. The printed circuit board device according to claim 1, wherein the outer diameter is set smaller than the outer diameter of the lower surface side.