JP2000216565A - Connection structure to chassis ground of circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a connection structure to the chassis ground of a circuit board in which inconvenience of clogging an insertion hole with solder is eliminated while preventing occurrence of non-soldered part. SOLUTION: A connection structure to the chassis ground of a circuit board comprises an insertion hole 2 for fixing screw, a ground pattern 1 surrounding the insertion hole 2 and a solder resist 5 provided on the ground pattern 1 wherein a ring-like resist punching part 10 surrounding the insertion hole 2 is provided in the solder resist 5 on the ground pattern 1 and one or more of resist bridge part 11 is formed at least a part of the ring-like resist punching part 10 in the circumferential direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a connection structure between a circuit board and a chassis ground.

[0002]

2. Description of the Related Art FIGS. 5 and 6 show examples of a conventional structure for connecting a circuit board to a chassis ground. FIG. 5 is a plan view from the solder surface before flowing into the solder bath, and FIG. 6 is a cross-sectional view taken along line BB of FIG. 5 after flowing through the solder bath. In both figures, reference numeral 3 denotes a circuit board having a signal ground pattern 1 and an insertion hole 2, and reference numeral 4 denotes a chassis ground for fixing and grounding the circuit board 3. Generally, such a circuit board 3
In an electronic device in which the signal ground pattern 1 on the circuit board 3 and the chassis ground 4 are electrically connected for the purpose of stabilizing the operation of the circuit board 3 and reducing radiation noise, in an electronic device in which the chassis ground 4 is fixed. It is required to connect to

In the case of the above prior art, the structure of such a chassis ground connection portion (hereinafter referred to as a CG connection portion) 9 is formed on the side of the base material 8 constituting the circuit board 3 facing the chassis ground 4. In the vicinity, a signal ground pattern 1 made of a solid copper foil pattern is provided, and a part of the solder resist 5 covering the upper surface thereof is removed in a ring shape, so that a ring-shaped resist removal portion 10 surrounding the insertion hole 2 is removed. It is formed by exposing the signal ground pattern 1 in a ring shape concentric with the insertion hole 2. Then, by flowing (immersing) this into the solder tank,
The solder 6 is raised above the solder resist 5 as shown in FIG. 6, a fixing screw 7 is passed through the insertion hole 2, and a screw is screwed to the chassis ground 4 to perform connection.

However, when removing the solder resist 5, as shown in FIG. 5, the solder resist 5 is removed in a circular shape with the insertion hole 2 as the center, and the ring-shaped resist removal portion 10 is simply removed.
In some cases, when the solder bath is flowed, there is a problem that not only the ring-shaped resist removal portion 10 but also the insertion hole 2 is filled with the solder 6. In such a case, the insertion hole A step of removing the solder 6 from 2 has additionally occurred. Also, when a dedicated jig is prepared and the solder 6 is removed from the insertion hole 2, there are problems such as an increase in jig manufacturing cost and an increase in the number of steps.

On the other hand, as shown in FIG. 7, there is also a grounding structure in which the signal ground pattern 1 of the circuit board 3 is made a solid pattern, the solder resist 5 is not provided on the signal ground pattern 1, and the signal ground pattern 1 is screwed to the chassis ground 4. Previously employed. However, if the CG connection portion 9 is formed into a solid pattern and is not entirely covered with the solder resist 5 and flows into the solder bath, the solder 6 may be excessively raised at the CG connection portion, or the insertion hole 2 may be soldered as shown in FIG. 6 easily fills up.

Therefore, in order to improve this, as shown in FIG. 9, a diagonal (about 45 °) stripe portion, that is, a stripe resist 51 is formed on the solid pattern of the CG connection portion 9 with the solder resist 5. A method is employed in which the signal ground pattern 1 exposed between the stripe resists 51 is soldered. The reason for forming the stripe resist 51 is to prevent the solder 6 from rising too much when flowing into the solder bath and to realize a reliable connection with the chassis ground 4 due to the presence of the stripe resist 51.

However, in the method in which the stripe resist 51 is provided on the solid copper foil pattern as shown in FIG. 9, since the copper foil to which the solder 6 is attached is recessed from the solder resist 5, the solder resist as shown in FIG. There is a drawback that a portion 61 with a mark and a portion without solder (a portion in an unsoldered state) 62 appear in a mixed state, and the soldering is likely to be incomplete. The unsoldered state means that the portion is not connected to the chassis ground 4 structurally.

[0008]

SUMMARY OF THE INVENTION It is an object of the present invention to eliminate the problem that the insertion hole for passing the fixing screw is closed by solder at the time of soldering, and to eliminate the occurrence of an unsoldered portion. It is an object of the present invention to provide a connection structure between a circuit board and a chassis ground.

[0009]

Means for Solving the Problems In order to achieve the above object, an invention according to claim 1 of the present application is directed to an insertion hole for a fixing screw, a ground pattern provided so as to surround the insertion hole, and a ground pattern provided on the ground pattern. A connection structure with a chassis ground of a circuit board provided with a solder resist provided on the ground pattern, wherein the solder resist on the ground pattern is provided with a ring-shaped resist removing portion surrounding the insertion hole, and the ring-shaped resist removing portion is provided. Characterized in that one or more cross-linking portions in which a resist exists are formed in at least a part of the circumferential direction.

According to the structure for connecting the circuit board to the chassis ground of the present invention, the solder resist is removed in a circular shape, and the removal of the solder resist is cut at one or two places (cross-linking of the resist). There is no problem that the insertion hole is filled with solder when flowing through the solder bath. This is presumably because the force relationship of the surface tension is lost.

According to a second aspect of the present invention, in the connection structure for connecting a circuit board to a chassis ground according to the first aspect, the bridging portion is located to face the diametrical direction of the insertion hole. As described above, an even number is provided. With such a number and arrangement of the bridge portions, it is possible to more reliably avoid the problem that the insertion holes are filled with the solder when flowing the solder bath.

According to a third aspect of the present invention, there is provided a connection structure of a circuit board having a through hole for a fixing screw and a ground pattern provided so as to surround the through hole, with a chassis ground. The ground pattern is formed as a stripe pattern composed of a plurality of stripes. In this embodiment, since the copper foil to which the solder is attached is exposed, there is obtained an advantage that an unsoldered portion hardly occurs when the copper foil is poured into the solder bath. Also, since the pattern is a stripe, it is possible to prevent the solder from rising too much.

According to a fourth aspect of the present invention, in the connection structure for connecting a circuit board to a chassis ground according to the third aspect, the stripe has an outer side than the insertion hole in a direction in which the stripe extends. A connection pattern portion is provided for connecting stripe portions that are isolated from each other. Since this connection pattern portion functions as a pattern for eliminating a floating pattern (isolated pattern), connection to the chassis ground can be ensured without waste.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the present invention. FIG. 1 is a plan view from the solder surface of the circuit board before flowing into the solder tank, and FIG. 2 is a cross-sectional view of the circuit board taken along line AA of FIG. 1 after flowing into the solder tank.

In both figures, reference numeral 3 indicates a circuit board, and reference numeral 4
Is a chassis ground which is a mating member to which the circuit board 3 is fixed and grounded. The circuit board 3 has a chassis ground 4
The CG connection portion 9 is provided with an insertion hole 2 for inserting the fixing screw 7. On both sides of the circuit board 3, ground patterns 1 made of a solid copper foil pattern are provided so as to surround the through holes 2.
The solder resist 5 is provided on the ground pattern 1 on the side of the base material 8 facing the chassis ground 4.

Further, the signal ground pattern 1
A ring-shaped resist removal portion 10 surrounding the insertion hole 2 is formed by removing a part of the solder resist 5 covering the upper surface of the solder resist 5 in a ring shape. Therefore,
The signal ground pattern 1 is exposed in the resist removal portion 10 in a ring shape concentric with the insertion hole 2.

The ring-shaped resist removal portion 10 has one or more cross-linking portions 11 in which a resist is present, at least in a part in the circumferential direction. In other words,
At least a part of the resist removal portion 10 in the ring circumferential direction is cut by the bridge portion 11. In this embodiment, four bridging portions 11 are arranged diametrically opposed to the insertion holes 2, whereby the four bridging portions 11 are equally divided into four resist-removed portion segments 12, which are arranged symmetrically as a whole. I have.

When the solder resist 5 is removed in a circular shape as described above, the removal of the solder resist 5 is cut by a plurality of cross-linking portions 11 (resist is applied). 6 does not cause the problem of filling. It is considered that this is because the surface tension of the solder 6 acting so as to cover the insertion hole 2 is reduced by the presence of the bridging portion 11 and the direction in which the solder acts is changed.

Accordingly, in an electronic device in which the circuit board 3 having the signal ground pattern 1 and the insertion hole 2 and the chassis ground 4 for fixing the circuit board 3 are incorporated, the operation of the circuit board 3 is stabilized and the radiation noise is reduced. To
The signal ground pattern 1 on the circuit board 3 can be satisfactorily connected to the chassis ground 4 by the fixing screw 7.

Next, FIGS. 3 and 4 show another embodiment of the present invention. FIG. 3 is a plan view from the solder surface of the circuit board before flowing into the solder tank, and FIG. 4 is a cross-sectional view of the circuit board after flowing into the solder tank.

In this embodiment, the CG connecting portion 9 of the circuit board 3 is connected to the chassis ground of the circuit board having the insertion hole 2 for the fixing screw 7 and the ground pattern 1 provided so as to surround the insertion hole 2. In the connection structure described above, the ground pattern 1 is formed as a stripe pattern composed of a plurality of stripes 13. That is, the CG of the circuit board 3
The signal ground pattern 1 in the connecting portion 9 is formed by stripes 13 of a striped pattern, and the solder resist 5 is not provided on the signal ground pattern 1 of the striped pattern.

According to the above configuration, since the copper foil to which the solder 6 is attached is exposed, when the copper foil flows into the solder bath,
No unsoldered portion 62 as shown in FIG.
That is, as shown in FIG. 4, the solder 6 is formed on each stripe 13 at a height exceeding the thickness of the solder resist 5 or lower. Moreover, since the signal ground pattern 1 has a stripe pattern composed of a plurality of stripes 13, it is possible to prevent the solder from rising too much.
In addition, even if the solder 6 is formed on each stripe 13 in a state smaller than the thickness of the solder resist 5, the ground connection is not affected. The reason is that the surface size of the CG connection portion 9 is equal to the top surface of the mounting projection of the chassis ground 4 (for example, 8 m
This is because the top surface of the mounting projection of the chassis ground 4 fits within the area of the CG connection portion 9.

Next, of the stripes 13, stripe portions (isolated stripe portions) 14 which are isolated in portions extending outside the insertion holes 2 in the extending direction thereof are provided in a direction intersecting with the stripe portions. Are connected to each other by the connection pattern unit 15. Due to the presence of the connection pattern portion 15, the isolated stripe portion 14 is no longer an isolated floating pattern. Therefore, the connection between the stripe 13 and the chassis ground 4 can be ensured without waste.

In the above embodiment, the solder resist 5 is not applied on the signal ground pattern 1. However, the solder resist 5 may be applied only between the patterns of the stripes 13 forming the stripe pattern. it can.

[0025]

As described above, according to the present invention,
Even when a part of the signal ground pattern is removed from the solder resist and flowed into the solder bath, the insertion hole is not filled with solder. For this reason, a step of removing solder from the insertion hole and a dedicated jig are not required. In addition, it is possible to prevent the connection strength from deteriorating due to the excessive removal of the solder, which occurs when the solder is removed. Furthermore, the occurrence of the unsoldered portion can be eliminated. Moreover, no additional cost is required to provide the structure of the present invention.

[Brief description of the drawings]

FIG. 1 is a partial plan view of a circuit board before flowing into a solder bath according to one embodiment of the present invention as viewed from a solder surface.

FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, showing a circuit board and a chassis ground after flowing into a solder bath according to one embodiment of the present invention.

FIG. 3 is a partial plan view of a circuit board before flowing into a solder bath according to another embodiment of the present invention, as viewed from a solder surface.

FIG. 4 is a cross-sectional view of a circuit board after flowing into a solder bath according to another embodiment of the present invention.

FIG. 5 is a partial plan view of a circuit board before flowing a conventional solder bath viewed from a solder surface.

FIG. 6 is a sectional view taken along the line BB of FIG. 5 showing a circuit board and a chassis ground after flowing a conventional solder bath.

FIG. 7 is a partial plan view of a conventional circuit board viewed from a solder surface.

8 is a cross-sectional view showing a state after the conventional circuit board of FIG. 7 has flowed into a solder bath.

FIG. 9 is a partial plan view of a conventional circuit board viewed from a solder surface.

FIG. 10 is a cross-sectional view showing a state after the conventional circuit board of FIG. 8 has been poured into a solder bath.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Signal ground pattern 2 Insertion hole 3 Circuit board 4 Chassis ground 5 Solder resist 6 Solder 7 Fixing screw 8 Base material 9 CG connection part 10 Resist removal part 11 Bridge part 12 Resist removal part segment 13 Stripe (striped pattern) 14 Isolated stripe part 15 Connecting pattern part 51 Stripe resist 61 Solder attached part 62 Unsoldered part

────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission Date] January 11, 2000 (2000.1.1)
1)

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Claims

[Correction method] Change

[Correction contents]

[Claims]

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] 0009

[Correction method] Change

[Correction contents]

[0009]

Means for Solving the Problems In order to achieve the above object, an invention according to claim 1 of the present application is directed to an insertion hole for a fixing screw, a ground pattern provided so as to surround the insertion hole, and a ground pattern provided on the ground pattern. a connecting structure between the chassis ground of the circuit board having a solder resist provided on the previous term of the ring-shaped resist vent portion surrounding the through hole in the solder resist on the ground pattern
Solder resist left at the periphery of the insertion hole
And at least one or more cross-linking portions in which a resist is present are formed on at least a part of the ring-shaped resist removal portion in the circumferential direction.

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0012

[Correction method] Change

[Correction contents]

According to a third aspect of the present invention, there is provided a connection structure of a circuit board having a through hole for a fixing screw and a ground pattern provided so as to surround the through hole, with a chassis ground. The perimeter of the insertion hole is
The ground pattern is formed without a ground pattern, and the ground pattern is formed as a stripe pattern composed of a plurality of stripes. In this embodiment, since the copper foil to which the solder is attached is exposed, there is obtained an advantage that an unsoldered portion hardly occurs when the copper foil is poured into the solder bath. Also, since the pattern is a stripe, it is possible to prevent the solder from rising too much.

Claims (4)

[Claims] 1. A connection structure with a chassis ground of a circuit board including an insertion hole for a fixing screw, a ground pattern surrounding the insertion hole, and a solder resist provided on the ground pattern. A ring-shaped resist removal portion surrounding the insertion hole is provided in the solder resist on the ground pattern, and one or more cross-linking portions in which a resist exists are formed on at least a part of the ring-shaped resist removal portion in the circumferential direction. A connection structure for connecting a circuit board to a chassis ground. 2. The connection structure according to claim 1, wherein an even number of the bridge portions are provided so as to face each other in the diameter direction of the insertion hole. 3. A connection structure with a chassis ground of a circuit board having a through hole for a fixing screw and a ground pattern provided so as to surround the through hole, wherein the ground pattern comprises a plurality of stripes. A connection structure with a chassis ground of a circuit board, which is formed as a stripe pattern. 4. The stripe according to claim 3, wherein the stripe is provided with a connection pattern portion that connects stripe portions that are isolated in a portion outside the insertion hole in a direction in which the stripe extends. Connection structure with the chassis ground of the circuit board to be used.