JP5869282B2 - Electrical connector - Google Patents

Description

  The present invention relates to an electrical connector that is surface-mounted on a circuit board.

  In general, a solder paste printing method is used as a technique for mounting an electrical connector on a circuit board. In this solder paste printing method, a metal mask having a plurality of openings with the same pitch as a plurality of conductive pads formed on a circuit board is used. In the solder paste printing method, the opening of the metal mask is aligned with the conductive pad on the circuit board, the metal mask is placed on the circuit board, and cream solder is applied from the metal mask. Thereby, cream solder is printed on the conductive pad on the circuit board through the opening. When mounting the electrical connector, the metal mask is removed from the circuit board, the board connection part of the electrical terminal of the electrical connector is placed on the printed cream solder, and the board connection part is soldered to the conductive pad by reflow soldering. To do.

By the way, in recent years, along with miniaturization of electronic devices, there is a demand for miniaturization and high density of electrical connectors, and there is a demand for narrow pitch between board connection portions in a plurality of electrical terminals.
However, the method of mounting the electrical connector on the circuit board using the solder paste printing method described above has a limit in narrowing the pitch between the board connecting portions. For example, when the pitch between the board connection portions is smaller than 0.35 mm, the cream solder cannot be appropriately printed on the plurality of conductive pads formed on the circuit board. The reason for this is that when the pitch between the substrate connection portions becomes narrow, the pitch of the conductive pads on which the cream solder is printed becomes narrow and the width of the conductive pads also becomes small. Correspondingly, the pitch and width of the openings of the metal mask are also reduced. Then, after applying the cream solder from the metal mask, when the metal mask is removed from the circuit board, the cream solder adheres to the opening of the metal mask, and the solder cream is not properly printed on the conductive pad. Because there is.

On the other hand, there is a method in which solder is attached to the electrical terminal side in advance when the board connection portion of the electrical terminal in the electrical connector is soldered to the conductive pad on the circuit board. According to this method, it is possible to cope with a narrow pitch between the substrate connecting portions.
As a conventional method of attaching solder to the electrical terminal side in advance of this type, for example, a technique shown in FIG. 7 is known (see Patent Document 1). FIG. 7 is a schematic diagram of an electrical connector in a state in which solder balls are attached to a board connection portion of a conventional electrical terminal.

As shown in FIG. 7, in the electrical connector 101, a solder ball 130 is attached to the board connection portion 121 of the electrical terminal 120 attached to the housing 110. The solder ball 130 is formed of a spherical body having a diameter larger than the width of the board connecting portion 121. When the solder ball 130 is attached to the board connecting portion 121, first, the solid solder ball 130 is placed on the lower surface of the board connecting portion 121 with the lower surface facing up. Next, the solder ball 130 is once melted by reflow soldering and then solidified to be fixed to the lower surface of the board connecting portion 121. During the reflow soldering, the spherical solder ball 130 is positioned in the recess 111 formed in the housing 110, and the position is maintained. Otherwise, the spherical solder balls 130 will fall off the lower surface of the board connecting portion 121.
Then, the solder balls 130 are soldered by reflow soldering to conductive pads provided on a circuit board (not shown).

JP 2008-300365 A

However, the electrical connector 101 shown in FIG. 7 has the following problems.
That is, in Patent Document 1, no consideration is given to how the shape or the like of the solder balls 130 is made when the pitch between the board connection portions 121 of the electrical terminals 120 is narrowed.

When the solder ball is formed of a spherical body having a diameter larger than the width of the board connecting portion as in the electrical connector 101 shown in FIG. 7, it is formed on a structure such as a housing during reflow soldering to the board connecting portion. It is necessary to hold the position of the solder ball with the recessed portion. If this is not done, the spherical solder balls will fall off the connection surface of the board connection portion. However, if the solder balls are held in the recesses formed in the structure such as the housing as described above, the soldered portion cannot be inspected from the outside of the housing after the board connecting portion is soldered to the circuit board. There is.
Therefore, in order to be able to inspect the soldered part from the outside of the housing, the diameter of the spherical body is made smaller than the width of the board connecting part so that it is not necessary to hold the solder ball during reflow soldering. It can be considered that it is placed on the surface and fixed by reflow soldering.

However, when the diameter of the spherical body is made smaller than the width of the board connecting portion in this way, when the pitch between the board connecting portions is narrowed, the width of the board connecting portion is reduced accordingly. For this reason, the diameter of the spherical solder ball fixed to the board connecting portion is also reduced. When the diameter of the solder ball is reduced, the volume of the solder ball is reduced, and there is a problem that the amount of solder is insufficient with respect to the amount of solder necessary for connection.
Accordingly, the present invention has been made in view of the above-described problems, and the object thereof is to enable a narrow pitch between board connection portions, which cannot be handled by a method of supplying solder to the circuit board side in advance. An object of the present invention is to provide an electrical connector that can secure the amount of solder necessary for connection even if the pitch between board connection portions is narrowed and the width of the board connection portion is reduced.

  To achieve the above object, an electrical connector according to claim 1 of the present invention is an electrical connector that includes a housing and electrical terminals attached to the housing and is surface-mounted on a circuit board, The electrical terminal has a board connecting portion soldered to the circuit board, and the board connecting portion is formed in a rectangular plate shape extending in the longitudinal direction and the width direction, and has a surface facing the circuit board. In the electrical connector in which the solder structure is provided on the surface and the solder structure is soldered to the circuit board by reflow soldering, the solder structure faces the circuit board. Formed in a three-dimensional shape having an elliptical shape when viewed from the circuit board side of the surface, the major axis direction of the elliptical shape being arranged in the longitudinal direction of the substrate connecting portion, and the minor axis direction of the elliptical shape There is disposed in the width direction of the board connecting portion, the major axis of the elliptical shape of the solder structure is characterized by greater than the width of the board connecting portion.

Furthermore, the electrical connector according to claim 2 of the present invention is the electrical connector according to claim 1 , wherein the solder structure is fixedly attached to a surface of the board connecting portion facing the circuit board. It is characterized by solder wetting.
In addition, an electrical connector according to a third aspect of the present invention is the electrical connector according to the first or second aspect , wherein a portion of the board connecting portion where the solder structure is provided is viewed from a plane side of the housing. And projecting outward from the housing.

  According to the electrical connector of the present invention, the board connecting portion is formed in a rectangular plate shape extending in the longitudinal direction and the width direction, and has a surface facing the circuit board. A solder structure is provided on this surface, and the solder structure is soldered to the circuit board by reflow soldering. For this reason, since the solder structure is provided in advance on the surface facing the circuit board of the board connecting portion on the electric connector side, the pitch between the board connecting portions cannot be reduced by the method of supplying solder to the circuit board side in advance. Can be made possible.

  The solder structure is formed in a three-dimensional shape having an elliptical shape when viewed from the circuit board side of the surface facing the circuit board. At the same time, the major axis direction of the ellipse is arranged in the longitudinal direction of the board connection part, the minor axis direction of the ellipse is arranged in the width direction of the board connection part, and the ellipse major axis of the solder structure is the width of the board connection part. Bigger than. For this reason, the volume of the solder structure is larger than the volume of the hemispherical solder ball when the diameter is the same as the width of the board connection portion. It is possible to increase the amount of solder by the hemispherical solder balls in the case of the same. Therefore, even if the pitch between the board connection portions is narrowed and the width of the board connection portion is narrowed, a sufficient amount of solder can be supplied with respect to the width compared to the hemispherical body, and the amount of solder necessary for connection Can be secured.

The principal part of 1st Embodiment of the electrical connector which concerns on this invention is shown, (A) is a left view, (B) is a front view, (C) is a bottom view. It is a fragmentary perspective view which shows the board | substrate connection part of the electrical terminal used for the electrical connector shown in FIG. 1 with a solder structure. The principal part of the modification of an electrical connector is shown, (A) is a left view, (B) is a front view, (C) is a bottom view. It is explanatory drawing for demonstrating an example of the mounting method to the circuit board of the electrical connector shown in FIG. 1A and 1B illustrate another example of a method for mounting the electrical connector shown in FIG. 1 on a circuit board, in which FIG. 1A is an explanatory diagram of a method for transferring flux to the surface of a solder structure, and FIG. It is explanatory drawing of the mounting method to the circuit board of the electrical connector by which the flux was transcribe | transferred on the surface. It is a left view of the principal part of 2nd Embodiment of the electrical connector which concerns on this invention. It is a schematic diagram of an electrical connector in a state where a solder ball is attached to a board connection portion of an electrical terminal of a conventional example.

Hereinafter, a first embodiment of an electrical connector according to the present invention will be described with reference to FIGS.
The electrical connector 1 shown in FIG. 1 is surface-mounted on a circuit board 50 (see FIG. 4). The housing 10 and a plurality (FIGS. 1A, 1B, 1C) show only one. ) Electrical terminal 20.
Here, the housing 10 is formed by molding an insulating synthetic resin, and has a substantially rectangular shape.

  As shown in FIG. 5, the plurality of electrical terminals 20 are attached at a predetermined pitch (for example, a pitch of 0.3 mm) in a line along the longitudinal direction of the housing 10. Each electrical terminal 20 includes a fixed portion 20a fixed to the housing 10 and a board connecting portion 21 extending from the fixed portion 20a. Each electrical terminal 20 is formed by punching and bending a conductive metal plate. As shown in FIG. 1A, the fixing portion 20 a of each electrical terminal 20 extends downward from the inside of the housing 10 and protrudes downward from the bottom surface of the housing 10. Each board connection portion 21 is bent by approximately 90 ° from the lower end of the fixed portion 20 a in a direction orthogonal to the longitudinal direction of the housing 10. Each board connecting portion 21 protrudes outward (right side in FIG. 1A) from the end wall 11 of the housing 10 when viewed from the plane side of the housing 10 (upper surface side in FIG. 1A). Each board connecting portion 21 is soldered to a conductive pad 51 (see FIG. 4) formed on the circuit board 50.

Here, each board connection portion 21 has a longitudinal direction of a terminal indicated by an arrow XX in FIG. 1C (a direction perpendicular to the longitudinal direction of the housing 10 described above) and an arrow YY perpendicular to the longitudinal direction. Are formed in a rectangular plate shape extending in the width direction of the terminal (longitudinal direction of the housing 10). Each board connection portion 21 has a lower surface 22 and an upper surface 23 as shown in FIGS. The lower surface 22 of the board connecting portion 21, as shown in FIG. 4, to face the circuit board 50, constituting the "circuit board facing the surface" as defined in the claims.

  In addition, a solder structure 30 is provided on the lower surface 22 of the board connecting portion 21 as shown in FIGS. 1 (A), (B), (C) and FIG. As will be described later, the solder structure 30 is soldered to the conductive pads 51 on the circuit board 50 by reflow soldering. The solder structure 30 is formed in a three-dimensional shape having an elliptical shape as shown in FIG. 1C when viewed from the circuit board 50 side, that is, the lower side of the lower surface 22. Here, the “elliptical shape” includes, in addition to the regular elliptical shape, a so-called saddle shape that partially has a linear portion. The solder structure 30 is arranged such that the major axis direction of the ellipse is in the longitudinal direction indicated by the arrow XX of the board connecting portion 21, and the minor axis direction of the ellipse is indicated by the arrow YY of the board connecting portion 21. It is arranged in the width direction. The major axis of the elliptical shape of the solder structure 30 is larger than the width of the board connection portion 21. The elliptical minor axis of the solder structure 30 is substantially the same as the width of the board connecting portion 21. Furthermore, the solder structure 30 is affinity-fixed on the lower surface 22 of the substrate connection portion 21 to establish solder wetting, and a fillet 31 is formed.

  Here, the solder structure 30 is formed in a so-called dome shape having an elliptical shape when viewed from the circuit board 50 side of the lower surface 22, and the major axis of the elliptical shape of the solder structure 30 is larger than the width of the board connecting portion 21. Is also getting bigger. For this reason, as shown in FIGS. 1A, 1B, 1C, hemispherical solder balls 40 having the same diameter as the width of the board connecting portion 21 (FIGS. The volume is larger by the amount indicated by the arrow a than (B) and (C) by the broken line). Therefore, by making the solder structure 30 into a three-dimensional shape having the elliptical shape as described above, the amount of solder is larger than that in the case of the hemispherical solder ball 40 in the case where the diameter is the same as the width of the board connection portion 21. Can be more.

Note that the minor axis of the elliptical shape of the solder structure 30 may be larger than the width of the board connecting portion 21 as in the modification shown in FIGS. 3 (A), (B), and (C). The elliptical minor axis of the solder structure 30 is such that the volume of the solder structure 30 is larger than the volume of the hemispherical solder ball 40 when the diameter is the same as the width of the board connection portion 21. The width may be smaller than the width of the board connecting portion 21.
Further, as shown in FIG. 1A, the portion where the solder structure 30 of the board connecting portion 21 is provided protrudes outward from the housing 10 when viewed from the plane side of the housing 10. In addition, there is no structure around the solder structure 30 that holds the solder structure 30 in the middle of fixing the solder structure 30 onto the board connection portion 21.

Next, a method for fixing the solder structure 30 onto the lower surface 22 of the board connecting portion 21 will be described.
First, a solid spherical solder ball having a diameter larger than the width of the board connection portion 21 is prepared, and the solder ball is discharged toward the lower surface 22 of the board connection portion 21. Next, before the solder ball lands on the lower surface 22 of the substrate connection portion 21, the solder ball is melted by irradiation of energy such as laser light, and the molten solder ball is landed on the lower surface 22. As a result, the melted solder balls are solidified and are firmly fixed to the lower surface 22, and the solder structure 30 is fixed on the lower surface 22.

  Note that the method of fixing the solder structure 30 on the lower surface 22 of the substrate connection portion 21 is not limited to this method. For example, the melted solder is ejected from a position separated from the lower surface 22 of the substrate connection part 21 as a spherical droplet having a diameter larger than the width of the substrate connection part 21 and landed on the lower surface 22. Also good. Alternatively, the solder structure 30 may be fixed on the lower surface 22 by applying cream solder on the lower surface 22 of the substrate connection portion 21 and then melting and then solidifying the cream solder.

Next, a method for mounting the electrical connector 1 on the circuit board 50 will be described with reference to FIG.
First, the circuit board 50 will be described. As shown in FIG. 4, a plurality of conductive pads 51 are formed on the circuit board 50 at the same pitch as the board connection portion 21 in the electrical connector 1.
Then, when mounting the electrical connector 1 on the circuit board 50, only the flux 32 is printed on the conductive pad 51 by a metal mask printing method or other methods. At this time, not only the flux 32 but also solder paste containing flux may be printed on the conductive pad 51. In this case, since the amount of solder is insufficient with only the solder paste, it is effective to provide the solder structure 30 on the lower surface 22 of the board connection portion 21.

Next, the electrical connector 1 in which the solder structure 30 is fixed on the lower surface 22 of the board connection portion 21 is placed on the circuit board 50 so that the solder structure 30 is positioned on the flux 32 as shown in FIG. To do.
The solder structure 30 is soldered to the conductive pads 51 on the circuit board 50 by reflow soldering. Thereby, the electrical connector 1 is mounted on the circuit board 50.
The method of mounting the electrical connector 1 on the circuit board 50 is not limited to this method, and may be the method shown in FIGS.

In this method, as shown in FIG. 5A, a jig 60 having a liquid flux 32 therein is prepared. The jig 60 is for accurately controlling the thickness (depth) of the liquid film of the flux 32.
When the electrical connector 1 is mounted on the circuit board 50, first, as shown in FIG. 5A, the solder structure 30 fixed to the lower surface 22 of the board connection portion 21 is immersed in the flux 32 of the jig 60. To do. Then, the electrical connector 1 is pulled up together with the solder structure 30. Thereby, an appropriate amount of flux 32 is transferred to the surface of the solder structure 30.

Next, as shown in FIG. 5B, the electrical connector 1 is placed on the circuit board 50 so that the solder structure 30 is positioned on the conductive pad 51 together with the flux 32.
The solder structure 30 is soldered to the conductive pads 51 on the circuit board 50 by reflow soldering. Thereby, the electrical connector 1 is mounted on the circuit board 50.

  Here, according to the electrical connector 1 according to the present embodiment, the board connecting portion 21 is formed in a rectangular plate shape extending in the longitudinal direction and the width direction, and has a lower surface 22, that is, a surface facing the circuit board 50. . A solder structure 30 is provided on the lower surface 22, and the solder structure 30 is soldered to the circuit board by reflow soldering. For this reason, since the solder structure 30 is provided in advance on the surface 22 facing the circuit board of the board connecting portion 21 on the electrical connector 1 side, the method of supplying solder to the circuit board side in advance cannot cope with the board connecting portion 21. It is possible to reduce the pitch between.

  The solder structure 30 is formed in a three-dimensional shape having an elliptical shape when viewed from the circuit board 50 side of the lower surface 22, the major axis direction of the elliptical shape is arranged in the longitudinal direction of the substrate connection portion 21, and the elliptical short shape is formed. The radial direction is arranged in the width direction of the board connecting portion 21. The major axis of the elliptical shape of the solder structure 30 is larger than the width of the board connection portion 21. For this reason, as described above, the volume of the solder structure 30 is larger than the volume of the hemispherical solder balls 40 when the diameter is the same as the width of the board connection portion 21, and the amount of solder by the solder structure 30 It is possible to increase the solder amount by the hemispherical solder balls 40 when the diameter is the same as the width of the board connection portion 21. Therefore, even if the pitch between the board connection portions 21 is narrowed and the width of the board connection portion 21 is narrowed, a sufficient amount of solder can be supplied with respect to the width compared to the hemispherical body, which is necessary for the connection. The amount of solder can be secured.

Further, according to the electrical connector 1 according to the present embodiment, the solder structure 30 is affinity-fixed on the lower surface 22 of the board connecting portion 21, that is, the surface facing the circuit board 50, and solder wetting is established. A fillet 31 is formed. For this reason, even if the pitch between the board connection parts 21 is narrowed and the gap between the board connection parts 21 is reduced, solder bridges between adjacent board connection parts 21 can be suppressed.
Furthermore, as described above, since the solder bridge between the adjacent substrate connection portions 21 can be suppressed, the solder resist for suppressing the solder bridge between the conductive pads 51 even if the pitch between the conductive pads 51 is narrowed. There is no need to provide.

  Further, the portion of the board connection portion 21 provided with the solder structure 30 protrudes outward from the housing 10 when viewed from the plane side of the housing 10. In addition, there is no structure around the solder structure 30 that holds the solder structure 30 in the middle of fixing the solder structure 30 onto the board connection portion 21. Thereby, after mounting the electrical connector 1 on the circuit board 50, the soldered portion can be inspected from the outside of the housing 10.

Next, a second embodiment of the electrical connector according to the present invention will be described with reference to FIG. In FIG. 6, the same members as those of the electrical connector shown in FIG.
The electrical connector 1 shown in FIG. 6 has the same basic configuration as the electrical connector 1 shown in FIG. 1, but differs in the number and shape of the solder structures 30 provided on the lower surface 22 of the board connection portion 21.

That is, in the electrical connector 1 shown in FIG. 6, there are a plurality of (two in the present embodiment) hemispherical solder structures 30 having the same diameter as the width of the board connection portion 21, and the lower surface of the board connection portion 21. 22 is provided. The plurality of solder structures 30 are arranged along the longitudinal direction of the board connecting portion 21. The solder structure 30 may be a spherical body or another shape instead of a hemispherical body, and the diameter may be larger or smaller than the width of the board connection portion 21.
As described above, a plurality of solder structures 30 are provided, and the plurality of solder structures 30 are arranged along the longitudinal direction of the board connecting portion. Thereby, even if the pitch between the board connection parts 21 is narrowed and the width of the board connection part 21 is reduced, a sufficient amount of solder can be supplied with respect to the width, and the amount of solder necessary for connection can be secured.

  Also in the electrical connector 1 shown in FIG. 6, the board connecting portion 21 is formed in a rectangular plate shape extending in the longitudinal direction and the width direction, and has a lower surface 22, that is, a surface facing the circuit board 50. A plurality of solder structures 30 are provided on the lower surface 22, and the plurality of solder structures 30 are soldered to the circuit board by reflow soldering. For this reason, since the solder structure 30 is provided in advance on the surface 22 facing the circuit board of the board connecting portion 21 on the electrical connector 1 side, the method of supplying solder to the circuit board side in advance cannot cope with the board connecting portion 21. It is possible to reduce the pitch between.

Also in the electrical connector 1 shown in FIG. 6, the solder structure 30 is affinity-fixed on the lower surface 22 of the board connecting portion 21, that is, the surface facing the circuit board 50, and solder wetting is established, and the fillet 31 Is formed. For this reason, even if the pitch between the board connection parts 21 is narrowed and the gap between the board connection parts 21 is reduced, solder bridges between adjacent board connection parts 21 can be suppressed.
Furthermore, since the solder bridge between the adjacent substrate connection portions 21 can be suppressed, it is not necessary to provide a solder resist for suppressing the solder bridge between the conductive pads 51 even if the pitch between the conductive pads 51 is narrowed. .

  Further, the portion of the board connection portion 21 provided with the solder structure 30 protrudes outward from the housing 10 when viewed from the plane side of the housing 10. In addition, there is no structure around the solder structure 30 that holds the solder structure 30 in the middle of fixing the solder structure 30 onto the board connection portion 21. Thereby, after mounting the electrical connector 1 on the circuit board 50, the soldered portion can be inspected from the outside of the housing 10.

  A method for fixing the plurality of solder structures 30 on the lower surface 22 of the board connecting portion 21 will be described below. For example, a plurality of solder structures 30 having a diameter equal to or smaller than the width of the board connecting portion 21 first. The solid solder balls are discharged toward the lower surface 22 of the board connecting portion 21. Next, before the solid solder ball lands on the substrate 22, the solid solder ball is melted by irradiation of energy such as laser light, and the melted solder ball is landed on the lower surface 22. This method is preferred. Further, a plurality of molten spherical solder droplets having a diameter equal to or smaller than the width of the board connection portion 21 are discharged from a position away from the lower surface 22 of the board connection portion 21 by a certain distance. A method of landing on the lower surface 22 may be used.

As mentioned above, although embodiment of this invention has been described, this invention is not limited to this, A various change and improvement can be performed.
For example, if the solder structure 30 is provided on the lower surface 22 of the board connecting portion 21, that is, the surface facing the circuit board 50, the solder structure 30 is not necessarily fixed on the surface and solder wetting is established. It does not have to be. In this case, it is preferable that the solder structure 30 is fixed to the board connection portion 21 with a mechanical structure such as an uneven shape or an adhesive.

Further, the portion of the board connection portion 21 provided with the solder structure 30 is not necessarily required to protrude outward from the housing 10 when viewed from the plane of the housing 10.
Further, when the portion of the board connection portion 21 provided with the solder structure 30 is projected outward from the housing 10 when viewed from the plane side of the housing 10, the board connection portion 21 is moved from the lower end of the fixing portion 20a to the housing 10. It is not always necessary to bend approximately 90 ° in the direction orthogonal to the longitudinal direction of the film.

DESCRIPTION OF SYMBOLS 1 Electrical connector 10 Housing 20 Electrical terminal 21 Board connection part 22 Lower surface (surface facing a circuit board)
30 Solder structure 31 Fillet 50 Circuit board

Claims (3)

An electrical connector comprising a housing and an electrical terminal attached to the housing, wherein the electrical terminal is surface-mounted on a circuit board, the electrical terminal having a board connection portion solder-connected to the circuit board, The board connecting portion is formed in a rectangular plate shape extending in the longitudinal direction and the width direction, and has a surface facing the circuit board, and a solder structure is provided on the surface, and the solder structure In an electrical connector that is soldered to the circuit board by reflow soldering,
The solder structure is formed in a three-dimensional shape having an elliptical shape when viewed from the circuit board side of the surface facing the circuit board, and the major axis direction of the elliptical shape is arranged in the longitudinal direction of the board connecting portion, The ellipse-shaped minor axis direction is arranged in the width direction of the board connecting portion, and the ellipse-shaped major axis of the solder structure is larger than the width of the board connecting portion. The solder structure, electrical connector according to claim 1, wherein the solder wetting and friendly affixed to the board connecting portion of the circuit board facing the on the surface is satisfied. 3. The electrical connector according to claim 1, wherein a portion of the board connecting portion on which the solder structure is provided protrudes outward from the housing when viewed from a plane side of the housing.

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