JP5272918B2 - Board device - Google Patents

Description

  The present invention relates to a board device including an external connection land that is brought into contact with an external connection conductor plate having a spring property.

  2. Description of the Related Art Conventionally, there is a substrate device on which an electrical component is mounted, in which an external connection land made of a conductor pattern is provided on a substrate and the external connection land is connected to an external circuit terminal. In this device, a wire is soldered to the external circuit terminal and the external connection land so that they are conductively connected.

However, in this case, one end and the other end of the wire must be soldered to the external circuit terminal and the external connection land, respectively, and this soldering operation is very troublesome.
As an improvement measure against this, one end of an external connection conductor plate made of a metal conductor plate having a spring property is connected to the external circuit terminal, and the other end side of the external connection conductor plate is used for the external connection of the substrate. There is a configuration in which the land is brought into contact with the land with the spring force (for example, Patent Document 1).

JP 10-149862 A

According to the configuration in which the external connection conductor plate having the spring property is brought into contact with the external connection land of the substrate in a pressure contact state with a spring force, the trouble of wire soldering is eliminated, but the conductor of the external connection land Since the pattern is exposed, the problem of oxidative corrosion remains and there is a risk of poor conduction between the land and the external connection conductor plate.
In order to improve this, it is considered to form a solder layer on the surface of the conductor pattern, but in this case, if the number of solder layer forming facilities and forming steps increases, there is a problem that the manufacturing cost increases.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a substrate device that can prevent oxidative corrosion of a land conductor pattern and suppress an increase in manufacturing cost.

  The present invention has been made by paying attention to the following points. The present inventor examined various soldering methods for forming a solder layer on the surface of the land conductor pattern. That is, as a technique for soldering to a substrate, a technique of manually using a soldering iron is generally known, but it takes time to form a solder layer manually. Takes and is not practical.

As another soldering technique, there is an industrial technique, which is roughly classified into reflow soldering and flow soldering.
The reflow soldering is a technique in which a solder paste (which is made by adding a flux to solder powder to have an appropriate viscosity) is printed on a substrate, electric components are placed on the solder paste, and heat is applied to melt the solder. .

  In addition, the flow solder has one surface of the substrate as an electric component placement surface and the other surface as a flow solder surface, and a terminal hole portion penetrating from the electric component placement surface to the flow solder surface is formed in the substrate, The electrical component is placed on the electrical component placement surface of the substrate, and the terminal of the electrical component is passed through the terminal hole, and in this state, the flow solder surface of the substrate is melted in the solder bath. This is a technique of soldering by immersing it in the surface layer of the solder.

  In order to form a solder layer on a land conductor pattern for external connection by the reflow soldering method, it is necessary to produce a printed pattern of solder paste having the same shape as the pattern on the land conductor pattern. Therefore, it is troublesome to set the shape of the printed pattern, and there is also the trouble of redesigning the entire printed pattern in which the printed pattern for forming the solder layer is added to the main circuit printed pattern. There is also a problem that the solder layer formed by heating and cooling the paste is easily peeled off.

  On the other hand, in the case of the method such as the flow solder, the molten solder in the solder bath is only immersed in the flow solder surface of the substrate, and the land formed on the electric component placement surface opposite to the flow solder surface is left as it is. The solder layer cannot be formed on the conductor pattern.

  Therefore, the present inventor has sought whether or not the molten solder in the solder bath can be guided to the electric component placement surface opposite to the flow solder surface, and as a result, the substrate is placed in the land conductor pattern region. It has been found that a solder layer can be formed on the surface of the land conductor pattern by forming a through-hole having such a size that the molten solder penetrates from the arrangement surface to the flow solder surface and can penetrate by capillary action.

The board device according to claim 1, which has been made in consideration of the above investigation results, has the board as an electrical component placement surface, the other side as a flow soldering surface, and terminals of the electrical component between the both sides as the electrical component. It has a structure having a terminal through-hole portion that penetrates from the arrangement surface to the flow solder surface, and the electric component is arranged on the electric component arrangement surface, and the terminal penetrates the terminal insertion hole portion and is flow soldered on the flow solder surface. The land for external connection is formed on the electric component placement surface of the substrate and the land conductor pattern region of the substrate is formed in the land conductor pattern region, and the substrate is connected to the flow solder from the electric component arrangement surface. A through-hole having a size that allows molten solder to penetrate into the surface by capillarity, and the land is formed by the flow solder and passes through the through-hole from the flow solder surface. Consist of a solder layer formed on the conductor pattern surface, further wherein the through hole is a plurality of regions of the conductor pattern for the land, both without the oval or elliptical, the longitudinal direction of the through hole in the respective It is characterized in that it is formed so that the ends of the two are close to each other .

  According to the substrate device of this configuration, when the terminals of the electrical component are flow soldered, the molten flow solder rises from the flow solder surface of the substrate through the through hole by capillary action, and the land conductor pattern The solder layer is formed on the surface of the land conductor pattern. In this way, a solder layer can be formed on the land conductor pattern when a terminal of an electrical component is soldered with a simple configuration such as forming a through hole, thereby suppressing an increase in manufacturing cost and a land conductor. Oxidative corrosion of the pattern can be prevented. Moreover, since the solder layer is fixed not only to the land conductor pattern but also from the surface of the land conductor pattern to the inside of the through hole, there is an effect that the solder layer is hardly peeled off from the land conductor pattern.

In this case, there are a plurality of the through holes in the area of the land conductor pattern, all of which are oval or elliptical, and are formed so that the end portions in the longitudinal direction of the respective through holes approach each other . . According to this, the molten solder that has lifted the through hole in the flow solder process is reliably formed as a solder layer on the surface of the land conductor pattern.

  That is, when the through hole has an elliptical shape or an elliptical shape, the molten solder that has moved up the through hole tends to overflow from the portion of the elliptical shape or the elliptical shape having a small curvature radius, that is, the end portion, onto the land conductor pattern. Therefore, according to the second aspect in which the end portions of the plurality of through-holes having an oval shape or an elliptic shape approach each other, the solder overflowing between the approaching both end portions extends toward the other end portion and is securely coupled. As a result, the molten solder that has raised the through-holes in the flow solder process is surely formed as a solder layer not only on the land conductor pattern surface but also on the land conductor pattern surface between the through-holes.

1 is a vertical side view of an external connection land portion of a board device according to a first embodiment of the present invention. A perspective view seen from above with the substrate device incorporated in the case A perspective view of the board device and the external connection terminal as seen from below. Perspective view of the external connection land as seen from below The perspective view of the board | substrate shown in the state before electrical component arrangement | positioning and solder layer formation Perspective view of land conductor pattern The perspective view of the board | substrate shown in the state before electrical component arrangement | positioning and solder layer formation Diagram for explaining flow soldering process Perspective view of external connection land after flow soldering FIG. 4 equivalent view showing the second embodiment of the present invention 1 equivalent diagram 7 equivalent diagram

  Hereinafter, a first embodiment of the present invention will be described with reference to FIGS. In FIG. 2, a substrate device housing portion 3 is formed in the case 2 of the electronic device 1, and the substrate device 4 is disposed in the substrate device housing portion 3 from above. An external connection conductor 5 having a spring property is attached to the case 2, and an external connection land 12 provided in the board device 4 when the board device 4 is housed in the board device housing portion 3. (Described later) comes into contact with the external connection conductor 5 in a pressure contact state.

  The said board | substrate apparatus 4 is demonstrated. 1 to 4, the substrate 6 of the substrate device 4 has one surface as an electric component placement surface 6a and the other surface as a flow solder surface 6b. And in this board | substrate 6, the terminal through-hole part 9 and 10 which penetrates the terminals 7a and 8a of the electrical components 7 and 8 from the said electrical component arrangement | positioning surface 6a to the flow solder surface 6b between the said both surfaces 6a and 6b (FIG. 5). Reference). Although not shown, terminal land portions to be soldered to the terminals 7a and 8a of the electrical components 7 and 8 are formed on the flow solder surface 6b side of the terminal through-hole portions 9 and 10.

The terminals 7a and 8a of the electric components 7 and 8 are arranged on the electric component arrangement surface 6a of the substrate 6, and the terminals 7a and 8a are penetrated by the terminal through-hole portions 9 and 10 and protruded from the flow solder surface 6b. The projecting end portion is soldered to the terminal land portion by flow solder described later.
Further, in the substrate 6, a closed loop GND conductor pattern 11 is formed on the electrical component placement surface 6 a so as to surround the terminal through-hole portions 9 and 10. An external connection land 12 is formed on the GND conductor pattern 11.

  As shown in FIGS. 1 to 6, the external connection land 12 includes a land conductor pattern 13, through holes 14 </ b> A and 14 </ b> B, and a solder layer 15. As shown in FIGS. 5 and 6, the land conductor pattern 13 is formed integrally with the GND conductor pattern 11, and in this case, the first land pattern portion 13a and the first land pattern portion 13a each having a substantially oval shape are formed. 2 land pattern portions 13b, and a connection pattern portion 13c that connects the land pattern portions 13a and 13b.

  The through hole 14A penetrates the substrate 6 from the electrical component placement surface 6a to the flow solder surface 6b in the first land pattern portion 13a region in the land conductor pattern 13 region of the substrate 6. Is formed. Further, the through hole 14B also penetrates the substrate 6 from the electric component placement surface 6a to the flow solder surface 6b in the second land pattern portion 13b region of the land conductor pattern 13 region of the substrate 6. Is formed.

  As shown in FIG. 6, these through holes 14A and 14B are all oval and formed so that the end portions 14A1 and 14B1 in the longitudinal direction of the respective through holes 14A and 14B approach each other. Furthermore, these through holes 14A and 14B are formed in a size (width dimension) that allows molten solder to enter by capillary action.

  The solder layer 15 is made of flow solder described later, and is formed on the surface of the land conductor pattern 13 from the flow solder surface 6 through the through holes 14A and 14B.

  Here, a procedure for soldering the terminals 7a and 8a of the electrical components 7 and 8 and forming the solder layer 15 will be described. As shown in FIG. 5, the electric component placement surface 6a of the substrate 6 is directed upward, and as shown in FIG. 7, each of the electric components 7, 8 is inserted into the terminal through holes 9, 10 of the electric component placement surface 6a. The electric components 7 and 8 are arranged on the electric component arrangement surface 6a in a form in which the terminals 7a and 8a are penetrated. In this state, as shown in FIG. 8, a flow soldering process is performed. In this flow soldering process, the flow solder surface 6b of the substrate 6 is immersed in a molten flow solder 16 accommodated in a flow solder bath (not shown).

  As a result, the terminals 7 a and 8 a protruding from the flow solder surface 6 b in the electrical components 7 and 8 are soldered to the terminal land portion (not shown) by the flow solder 16. At the same time, the molten flow solder 16 rises from the flow solder surface 6a of the substrate 6 through the through holes 14A and 14B by capillarity, and from the upper end openings of the through holes 14A and 14B onto the land conductor pattern 13 surface. Overflow and spread.

  In this case, since the through holes 14A and 14B have an oval shape, the molten solder that has moved up the through holes 14A and 14B has a conductor pattern for land from a portion of the oval with a small radius of curvature, that is, from the end portions 14A1, 14A2, 14B1, and 14B2. It is easy to overflow on 13th. Since the end portions 14A1 and 14B1 of the oval through holes 14A and 14B approach each other, the solder 16 overflowing between the approaching both end portions 14A1 and 14B1 joins the pattern 13c to the other end side. It extends and comes to join securely. Further, the melt flow solder 16 overflows from the side end portions of the through holes 14A and 14B extending in the longitudinal direction, and spreads on the first land pattern 13a and the second land pattern 13b. The flow solder 16 is cooled and solidified to form the solder layer 15 on the surface of the land conductor pattern 13. A solder filling portion 15a integrated with the solder layer 15 is formed in the through holes 14A and 14B.

  When the solder layer 15 of the board device 4 that has been subjected to the flow soldering process as described above faces downward and is accommodated in the board device accommodation portion 3 of the case 2 as shown in FIG. 2, the solder layer of the external connection land 12 is disposed. 15 abuts against the external connection conductor 5 and pushes it down. Thereby, the external connection land 5 is elastically deformed and press-contacted with the external connection land 12 by its own spring force.

  At this time, as shown in FIG. 4, the external connection conductor 5 contacts (contacts) a portion 12a (a portion of the connecting pattern 13c) between the end portions of the through holes 14A and 14B in the external connection land 12. The shape and length are set in advance so that the portion is indicated by 5a).

  As described above, according to the present embodiment, the substrate 6 on which the terminals 7a and 8a of the electrical components 7 and 8 are soldered by flow soldering is used as the substrate, and the land for the land provided on the electrical component placement surface 6a of the substrate 6 The solder layer 15 can be formed on the land conductor pattern 13 when the terminals 7a and 8a of the electrical components 7 and 8 are soldered with a simple configuration in which the through holes 14A and 14B are formed in the conductor pattern 13 region. Therefore, the oxidative corrosion of the land conductor pattern 13 can be prevented, and an increase in manufacturing cost can be suppressed. Moreover, since the solder layer 15 is fixed not only to the land conductor pattern 13 but also from the surface of the land conductor pattern 13 to the through holes 14A and 14B, the solder layer 13 is formed from the land conductor pattern 13. There is also an effect that it is difficult to peel off.

  Further, according to the present embodiment, there are a plurality of the through holes 14A and 14B in the area of the land conductor pattern 13, each of which has an oval shape, and the end portions in the longitudinal direction of the respective through holes 14A and 14B. 14A1 and 14B1 are formed so as to be close to each other, so that the molten solder that has risen through the through holes 14A and 14B in the flow soldering process is surely formed as the solder layer 15 on the surface of the connecting pattern 13c between the through holes 14A and 14B. Can do.

  That is, when the through holes 14A and 14B have the above-described oval shape, the molten solder that has moved up the through holes 14A and 14B has a small radius of curvature, that is, ends 14A1, 14A2, 14B1, and 14B2. It tends to overflow on the pattern 13. Therefore, according to the present embodiment in which the end portions 14A1 and 14B1 of the plurality of oval through holes 14A and 14B approach each other, the solder overflowing between the approaching both end portions 14A1 and 14B1 moves toward the opposite end portion. As a result, the molten solder that has risen through the through holes 14A and 14B in the flow solder process is surely formed as the solder layer 15 on the connecting pattern 13c between the through holes 14A and 14B. become. After that, the molten solder spreads on the surface of the first land pattern 13a around the through hole 14A and the second land pattern 13b around the through hole 14B, and the solder layer 15 is formed on the entire surface of the land conductor pattern 13. .

  When the solder layer 15 is formed by overflowing the flow solder 16 over the land conductor pattern 13 via the through holes 14A and 14B, the molten solder is cooled and solidified in the through holes 14A and 14B. There may be a shrinkage (dent) in the solder. For this reason, if the external connection conductor plate 5 is brought into contact only with the through holes 14A and 14B in the external connection land 12, contact reliability may be low and conduction may be uncertain.

  In this regard, according to the present embodiment, the external connection conductor plate 5 is connected to the external connection land 12 at the portion 12a between the adjacent end portions 14A1 and 14B1 of the through holes 14A and 14B, that is, the portion having no shrinkage. Since it is configured to be in contact with the external connection land 12, reliable conduction between the external connection land 12 and the external connection conductor plate 5 can be achieved. Moreover, since the solder layer 15 of the portion 12 a is on the substrate 6, the solder layer 15 is not depressed due to the spring force (pressure contact force) of the external connection conductor plate 5.

In the first embodiment, the through holes 14A and 14B are formed in an oval shape, but may be formed in an oval shape.
Next, a second embodiment of the present invention will be described with reference to FIGS. In the second embodiment, the land conductor pattern 21 of the external connection land 20 has a substantially square shape, and three through holes 22A, 22B, and 22C are formed in the area of the land conductor pattern 21. Yes. These through-holes 22A, 22B, and 22C are all oval, and the through-holes 22A, 22B, and 22C are formed so that the edges extending in the longitudinal direction are close to each other in a substantially parallel manner.

  The solder layer 23 of the external connection land 20 is also formed on the surface of the land conductor pattern 21 by the aforementioned flow soldering process. In this flow soldering process, the molten solder that has risen through the oval through holes 22A, 22B, and 22C tends to overflow from the end portions of the through holes 22A, 22B, and 22C as described above. It overflows also from the edge part extended in the longitudinal direction of through-hole 22A, 22B, 22C. In this case, in the second embodiment, the through holes 22A, 22B, and 22C are formed so that the edges extending in the longitudinal direction are close to each other in a substantially parallel manner, so that the adjacent through holes 22A, 22B, and 22C are adjacent to each other. It is possible to form a wide range of solder layers 23 by bonding the solder between the respective edges, and therefore, it is suitable when the land conductor pattern 21 is to be formed widely as in this embodiment.

In the second embodiment, the external connection conductor plate 5 is brought into contact with the external connection land 20 in a form straddling the plurality of through holes 22A, 22B, and 22C. According to this configuration, the external connection conductor plate 5 can be reliably brought into contact with the solder layer 23 of the portions 20a, 20b between the plurality of through holes 22A, 22B, 22C that are not thinned in the external connection land 20. In addition, since the solder layer 23 of the portions 20a and 20b is on the substrate 6, the solder layer 23 is not depressed due to the spring force of the external connection conductor plate 5, and generally in the second embodiment. In addition, reliable conduction between the external connection land 20 and the external connection conductor plate 5 can be achieved.
The present invention is not limited to the above-described embodiments, and can be implemented with various modifications such as a configuration in which one through hole is provided.

  In the drawings, 1 is an electronic device, 2 is a case, 3 is a board housing portion, 4 is a board device, 5 is an external connection conductor, 6 is a board, 6a is an electric component placement surface, 6b is a flow solder surface, and 7 and 8 are Electrical components, 7a and 8a are terminals, 9, 10 are terminal through holes, 11 is a GND conductor pattern, 12 is an external connection land, 13 is a land conductor pattern, 14A and 14B are through holes, 15 is a solder layer, 20 is an external connection land, 21 is a land conductor pattern, 22A, 22B, and 22C are through holes, and 23 is a solder layer.

Claims (1)

A board device having an external connection land on which electrical components are mounted and in contact with an external connection conductor plate,
The substrate has a structure including a terminal through-hole portion through which one side is an electrical component placement surface and the other side is a flow solder surface, and a terminal of the electrical component is passed between the both sides from the electrical component placement surface to the flow solder surface.
The electrical component is disposed on the electrical component placement surface, and the terminal is flow soldered on the flow solder surface through the terminal insertion hole,
The external connection land,
A land conductor pattern formed on the electrical component placement surface of the substrate;
A through hole formed in the conductor pattern region for the land of the substrate, and having a size sufficient to penetrate the substrate from the electric component placement surface to the flow solder surface and allow molten solder to enter by capillary action;
A solder layer formed on the surface of the land conductor pattern through the through-hole from the flow solder surface and configured by the flow solder;
Further, the through hole has a plurality in the region of the land conductor pattern, each of which has an oval shape or an oval shape, and is formed so that end portions in the longitudinal direction of the respective through holes are close to each other. A substrate device.

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