JPH08186360A - Printed wiring board - Google Patents

Abstract

PURPOSE: To increase solder attached to the lead of an electronic part in volume when the lead is made to pass through a molten solder tank so as to surely connect the lead to a conductive foil pattern by a method wherein a bridging-preventing solder- attached resist layer provided with a circular or elliptical cutout corresponding to a land is formed overlapping a first solder-attached resist layer. CONSTITUTION: When a part lead connecting land 5 is made to pass through a molten solder tank, solder is attached to a part lead 8 inserted into a part insertion hole 2 and the land 5. When the land 5 is made to pass through the molten solder tank, solder 9 is moved towards a part lead 8 by the action of its surface tension basing on a first solder-attached resist layer 3 formed around the land 5 and a bridging- preventing solder-attached resist layer 4 which is provided with a circular or elliptical cutout corresponding to the land 5 and formed overlapping the first solder-attached resist layer 3, and solder attached to both the part lead 8 and the part connecting main land 5 can be secured large enough in volume, so that the lead 8 and the land 5 are enhanced in soldering strength between them. Therefore, the connection of the lead 8 of an electrical part or the like with the lead connecting land 5 is improved in strength.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a printed wiring board provided with a plurality of conductive foils for connecting electronic parts by soldering or the like.

[0002]

2. Description of the Related Art Dip soldering is performed as an example of means for connecting electronic parts and the like to a printed wiring board by soldering. In this method, a lead of an electronic component is inserted into an insertion hole of a printed wiring board, immersed in a molten solder bath, and the conductive foil pattern of the printed wiring board and the lead are automatically soldered.

A conventional printed wiring board will be described below with reference to FIGS. 9, 10 and 11. As shown in FIGS. 9 and 10, in the conventional printed wiring board, the conductive foil pattern 34 is provided on the surface of the substrate 31, and the conductive foil pattern 3 is formed.
A component connecting land 32 is formed on the surface 4, and a component inserting hole 33 is formed in the component connecting land 32.

FIG. 11 shows a state after the lead 36 of the electronic component 35 is inserted into the component insertion hole 33 of the substrate 31 and dipped in a molten solder bath (not shown). Some of the solder 37 in the molten solder bath adheres to the component connecting lands 32 of the substrate 31, but the amount of solder adhered to the leads 36 and the component connecting lands 32 (corresponding to the length l ₀ ) is not sufficiently secured. , The strength of soldering between the lead 36 and the solder 37 is insufficient, and the solder 37
Since only the strength of the component lead connecting land 32 is strong, the lead 36 may be disengaged from the solder 37 by a slight impact, resulting in lack of reliability.

For this reason, after passing through the solder bath in order to secure the strength, the amount of solder is added manually by a worker or automatically soldered by a robot, or the amount of solder adhered is secured by the use of eyelets. Means are used.

[0006]

As described above, in the conventional configuration, it takes time and labor in the process, and especially in the case of manual work, the operator forgets to add the amount of solder to a specific location due to mistakes or omission of instructions. Therefore, there is a problem as a means for improving the reliability of soldering.

The present invention solves the above-mentioned conventional problems by increasing the amount of solder adhering to the periphery of the leads of an electronic component when passing through a molten solder bath, so that the leads of the electronic component and the conductive foil pattern are It is an object of the present invention to provide a user-friendly printed wiring board that ensures reliable connection.

[0008]

To achieve this object, the first means of the printed wiring board of the present invention is to attach a component formed by a conductive foil to the surface of the substrate, or a circular shape for component lead connection. On an oval land, a component insertion hole for inserting a component lead provided inside the land, a first layer of soldering resistance layer formed around the land, and a first layer of soldering resistance layer And a bridge-preventing soldering resistance layer having a circular or oval cutout formed on the land.

The second means of the printed wiring board of the present invention is to provide a circular or oval land for component lead connection for mounting a component formed of a conductive foil on the surface of the substrate, and the inside of the land. The component insertion hole for inserting the provided component lead, the first-layer soldering resistance layer formed around the land, and the first-layer soldering resistance layer are overlapped with each other to form the land. A soldering resistance layer for preventing bridging in which a circular or oval notch is formed on the land, and the land is a circular or oval main land portion centered on the component insertion hole; and the main land portion. And the bridging prevention soldering resistance layer is formed so as to have a circular or elliptical sub-land portion that is in contact with the main land portion and is smaller than the size of the main land portion.

The third means of the printed wiring board according to the present invention is a component insertion hole for inserting a plurality of component leads provided at a constant interval on the substrate, and a conductive foil centered on the component insertion hole. A plurality of formed circular or oval lands for connecting component leads, a first-layer soldering resistance layer formed around the lands, and a first layer of soldering-resistive layer And a bridge resistance soldering resistance layer in which a circular or oval cutout is formed on the land, the land being a circular or oval main land centered on the component insertion hole. And a sub-land portion that is in contact with the main land portion and has a circular shape or an oval shape that is equal to or smaller than the size of the main land portion, and the sub-land portion is located at a position where the adjacent main land portions are closest to each other. Form the soldering resistance layer for bridging prevention so that it is not provided. It become one.

A fourth means of the printed wiring board according to the present invention is to arrange a plurality of lands arranged on the surface of the substrate at equal intervals in a circular shape or an oval shape for connecting component leads for mounting components formed of a conductive foil. A component insertion hole for inserting a component lead provided in the center of the land, a first layer of soldering resistance layer formed around the land, and a first layer of soldering resistance layer A bridge resistance soldering resistance layer formed by stacking and forming a circular or oval cutout on the land, the land being a circular or oval main centered on the component insertion hole. The bridging preventing soldered resistance layer is formed so as to have a land portion and a sub-land portion that is in contact with the main land portion and has a circular shape or an oval shape that is smaller than or equal to the size of the main land portion, and the adjoining The sub land is diagonally above the part insertion hole. It is obtained by arranged with a predetermined distance.

[0012]

In the first means, when the land for connecting the component lead is passed through the molten solder bath, the solder is attached to the component lead and the land inserted in the component insertion hole. When passing through this molten solder bath, the first layer of soldering resistance layer formed around the land and the solder resistance layer formed on top of it are formed to form a circular or oval notch on the land to prevent bridging. Due to the soldering resistance layer, the solder moves from the periphery of the land where the component lead is inserted to the component lead side, and the solder adhesion amount increases.

In the second means, when the solder is attached to the main land portion and the sub land portion which are formed of the soldering resistance layer for bridging prevention and have a circular shape or an oval shape, the shape is larger than that of the main land portion. The surface tension of the solder acts on the sub-land portion having a small size, and the solder moves in the lead direction, increasing the amount of solder adhesion.

Further, in the third means, when solder is attached to the main land portion and the sub land portion formed in a circular or oval shape by the bridging prevention soldering resistance layer, a connector, an IC or the like is attached. When the component insertion holes are provided at regular intervals, the solder bridge does not occur because the sub-land portion is not provided at the position where the adjacent main land portions are closest to each other. From the lead side to the lead side, and the amount of attached solder increases.

In the fourth means, if there are many components to be mounted on the board, the component insertion holes will be very adjacent to each other in the vertical and horizontal directions. However, the sub land is diagonally above the component insertion hole. In addition, by arranging with a certain distance, solder bridge does not occur between adjacent lands even when passing through the molten solder bath, and the solder moves to the lead side due to the existence of the sub-land portion, and solder adhesion The amount increases.

[0016]

Embodiments of the present invention will be described below with reference to the drawings.

(Embodiment 1) As shown in FIGS. 1 and 2, 1
Is a conductive foil pattern made of copper foil or the like bonded to the substrate 6,
2 is a component insertion hole formed in the land 5 for connecting component leads, 3 is a first soldering resistance layer (hereinafter referred to as solder resist) formed around the land 5, 4 is on the solder resist 3 Is a soldering resistance layer (hereinafter referred to as a double mask) for preventing bridging, which has a notch on the land 5 formed by being overlapped with each other. The land 5 is in contact with the circular main land portion 5a centered on the component insertion hole 2 formed by the double mask 4 and the main land portion 5a.
It is formed by a combination with a circular sub-land portion 5b having a diameter smaller than a. Further, 6 is a substrate.

With respect to the printed wiring board having the above structure, the relationship between the respective constituent elements will be described with reference to FIG. The leads 8 of the electronic component 7 are inserted into the component insertion holes 2 of the board 6, and when passing through a molten solder bath (not shown), the solder adheres to the component leads 8 and the lands 5, but the solder of the double mask 4 is removed. Due to the shape formed by the notch, the solder 9 moves to the component lead 8 side by the action of the surface tension of the solder itself, and a sufficient amount of solder is secured in the component lead 8 and the main land portion 5a for connecting the component. The adhesion strength can be increased.

Although the conductive foil pattern of the land 5 is an elliptical shape in FIG. 1, it may be a circular shape. Also, double mask 4
The shape of the land 5 formed by the above is a circular main land portion 5a and a circular sub land portion 5b.
Any combination of oval and oval may be used.

(Second Embodiment) A second embodiment of the present invention will be described below with reference to FIGS. 3 and 4. As shown,
The sub land portions 5b are arranged in a straight line with the component insertion hole 2 as the center. It should be noted that d ₁ and d ₂ indicate intersections of the main land portion 5a and the sub land portion 5b.

In the above structure, the tall electronic component 10
8 is inserted into the component insertion hole 2 of the board 6, and when passing through a molten solder bath (not shown), the solder adheres to the component lead 8 and the land 5, but is formed by the double mask 4. By this, the surface tension action of the solder itself acts on the solder 9, and the solder moves in the P ₀ direction from the sub land portion 5b to the main land portion 5a, and the intersections d ₁ and d _{2 of the} main land portion 5a and the sub land portion 5b. Therefore, the amount of solder attached to each outer portion is reduced, but the amount of solder attached to the component lead 8 side is increased.

Further, after the tall electronic component 10 is mounted, if there is a possibility that some load is applied in the A or A'direction due to its structure, as in this embodiment, B is used.
In the −B ′ direction, the soldering strength is improved due to the existence of the sub-land portion 5b, which is effective for the applied load.

In FIG. 3, the conductive foil pattern 1 forming the land 5 has an elliptical shape, but it may have a circular shape. Further, although the main land 5a and the sub-land portion 5b formed by the double mask 4 are circular and circular in shape, they may be any combination of circular and oval, or oval and oval.

(Embodiment 3) A third embodiment of the present invention will be described below with reference to FIGS. In this example, the lands 5 are arranged in parallel with each other at a pitch of Xp, and the sub-land portions 5b are arranged at regular intervals of 90 degrees except for the position where the adjacent main land portions 5a are closest to each other. There is. In addition,
dx ₁ and dx ₂ indicate the intersections of the main land portion 5a and the sub land portion 5b.

In the above structure, the lead 8 of the electronic component 7
Is inserted into the component insertion hole 2 of the substrate 6, and the solder (not shown) in the molten solder bath adheres to the leads 8 of the electronic component 7 when passing through the molten solder bath (not shown). , The main land portion 5a formed by the notch of the double mask 4
And the sub-land portion 5b causes the surface tension of the solder to act,
The solder moves from the sub land portion 5b in the P ₁ direction. Then, the intersection d of the main land portion 5a and the sub land portion 5b
Although the amount of solder attached to the outer portions of x ₁ and dx ₂ is smaller than that of x ₁ and dx ₂ , the amount of solder attached to the component leads 8 is increased.

Further, when mounting and soldering a component having a narrow component insertion hole pitch adjacent to the component insertion hole 2, for example, a microcomputer, if the sub land portion 5b is provided inside the adjacent pitch, the sub land portion 5b is provided. If they come too close to each other and pass through the molten solder layer, a solder bridge easily occurs between adjacent lands. Therefore, if the auxiliary land 5b is not provided at the position where the adjacent main land portions 5a are closest to each other as in the present embodiment, but is provided in the direction in which there is no adjacent land, a solder bridge does not occur and the solder adhesion amount Is secured, and soldering strength is improved.

In FIG. 5, the sub-land portion 5b is 90 °.
I placed them at intervals, but it doesn't matter. Further, the shapes of the main land portion 5a and the sub land portion 5b formed by the notches of the double mask 4 may be any combination of a circle and an ellipse, or an oval and an ellipse.

(Fourth Embodiment) A fourth embodiment of the present invention will be described below with reference to FIGS. 7 and 8. In this example, a large number of lands 5 are arranged close to each other at a horizontal pitch Xc and a vertical pitch Yc, and the sub land portion 5b has a component insertion hole 2a.
On the other hand, they are arranged diagonally and at a predetermined distance.

FIG. 7 shows a state in which the component insertion holes 2 are adjacent to each other in the horizontal direction and the vertical direction, and the pitch Xc in the horizontal direction is shown.
(X _A -x _B), when the vertical pitch Yc (y _A -y _B) is the same, 45 ° inclined relative to a vertical line through the auxiliary land part 5b formed by the notches of the double mask 4 parts insertion hole 2 , By providing at four positions at 90 ° pitch, the solder moves toward the main land portion 5a by the action of the surface tension and increases the solder adhesion amount, as described in FIG. 6 of the third embodiment. As a result, the adhesive strength between the component lead 8 and the land 5 is improved.

FIG. 8 shows the shape of only the main land portion 5a and the sub-land portion 5b formed by the notches of the double mask 4. The distances A, A ', C, C'from the center of the component insertion hole 2 to the adjacent main lands and the diagonal distances B, B'of the sub lands 5b are both sufficiently insulated. It is possible to ensure dripping and soldering strength.

In this embodiment, the shape of the main land portion 5a and the sub land portion 5b formed by the double mask 4 is a combination of a circle and a circle.
Any combination of oval and oval may be used.

[0032]

As is apparent from the above description, in the structure of claim 1 of the present invention, the component lead connection land is a circular or elliptical notch formed on the land when passing through the molten solder bath. Due to the double mask having the solder, the solder moves from the periphery of the land where the component lead is inserted to the component lead side, and the solder adhesion amount increases. Therefore, it is possible to realize a user-friendly printed wiring board that strengthens the connection between the lead of the electronic component or the like and the land for lead connection.

According to the second aspect of the present invention, by providing the main land portion, even if a tall component of the component main body is attached and a load is applied to the component, the load is likely to be applied. Providing a printed wiring board that is easy to use without worrying about solder cracks, etc., because the amount of solder attached increases and the soldering strength is improved by aligning the direction of the sub-lands. You can

According to the third aspect of the present invention, when a plurality of component insertion holes are provided at regular intervals, the sub-land portions are provided at positions other than the positions where the adjacent main land portions are closest to each other. A solder bridge does not occur between the adjacent main lands even when the printed wiring board is passed through the tank, the solder joint strength is improved by the action of the sub-lands, and a highly reliable and easy-to-use printed wiring board can be provided.

Further, in the structure according to the fourth aspect, when the component insertion holes are provided adjacent to each other in the horizontal direction and the vertical direction, the sub-land portions are provided diagonally, and the sub-land portions are provided diagonally from the main. The amount of solder attached to the land portion is increased, and the solder joint strength between the component lead and the main land portion is improved. Further, a sufficient insulation distance from the component insertion hole is secured, and a highly reliable printed wiring board can be provided.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a printed wiring board according to a first embodiment of the present invention.

FIG. 2 is a cross-sectional view of the printed wiring board according to the first embodiment of the present invention when solder is attached when component leads are inserted.

FIG. 3 is a configuration diagram of a printed wiring board according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view of a printed wiring board according to a second embodiment of the present invention when solder is attached when a component lead is inserted.

FIG. 5 is a configuration diagram of a printed wiring board according to a third embodiment of the present invention.

FIG. 6 is a sectional view of a printed wiring board according to a third embodiment of the present invention in which solder is attached when component leads are inserted.

FIG. 7 is a configuration diagram of a printed wiring board according to a fourth embodiment of the present invention.

FIG. 8 is a diagram showing a state of a component connection land and an insulation distance of a printed wiring board according to a fourth embodiment of the present invention.

FIG. 9 is a configuration diagram of a conventional printed wiring board.

FIG. 10 is a configuration diagram of another conventional printed wiring board.

FIG. 11 is a cross-sectional view when solder is attached to a conventional printed wiring board when component leads are inserted.

[Explanation of symbols]

 1 Conductive Foil Pattern 2 Component Insertion Hole 3 Solder Resist 4 Double Mask 5 Land 5a Main Land 5b Sub Land 6 Substrate

Claims (4)

[Claims] 1. A circular or oval land for connecting component leads, which mounts a component formed of a conductive foil, on the surface of a substrate, and a component insertion hole for inserting a component lead provided inside the land, A bridge formed by stacking a first soldering resistance layer formed around a land on the first soldering resistance layer and forming a circular or oval cutout on the land. A printed wiring board having a protective soldering resistance layer. 2. A circular or oval land for connecting component leads for mounting a component formed of a conductive foil on a surface of a substrate, and a component insertion hole for inserting a component lead provided inside the land, A bridge formed by stacking a first soldering resistance layer formed around a land on the first soldering resistance layer and forming a circular or oval cutout on the land. A solder resistance layer for prevention, the land is a circular or oval main land portion centered on the component insertion hole, and is in contact with the main land portion, and less than or equal to the size of the main land portion. A printed wiring board formed by forming the bridging prevention soldering resistance layer so as to have a circular or oval sub-land. 3. A component insertion hole for inserting a plurality of component leads provided at a constant interval on a substrate, and a circular or oval shape for connecting component leads formed of a conductive foil centering on the component insertion hole. A plurality of lands, a first-layer soldering resistance layer formed around the lands, and a first or second soldering resistance layer are overlaid on each other to form a circular or oval shape. A bridge-preventing soldering resistance layer having a cutout formed therein, the land being a circular or oval main land portion having the component insertion hole as a center, and the main land portion being in contact with the main land portion; And a circular or oval sub-land portion having a size equal to or less than the size of the sub-land portion, and the sub-land portion is not provided at a position where the adjacent main land portions are closest to each other. A printed wiring board formed by forming. 4. A plurality of lands arranged at equal intervals in a circular shape or an oval shape for connecting component leads for mounting components formed of a conductive foil on the surface of a substrate, and component leads provided at the center of the lands. The component insertion hole to be inserted, the first layer of soldering resistance layer formed around the land, and the first layer of soldering resistance layer are overlapped with each other to form a circle or a long shape on the land. A bridge-preventing soldering resistance layer in which a circular cutout is formed, wherein the land is a circular or oval main land portion having the component insertion hole as a center, and the main land portion is in contact with the main land portion; The soldering resistance layer for bridging prevention is formed so as to have a circular or oval sub-land portion having a size equal to or smaller than the size of the land portion, and the adjacent sub-land portion is diagonal to the component insertion hole. Printed wiring board arranged with a certain distance above.