JP2018129463A - Printed circuit board and printed circuit device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a printed circuit board in which a sufficient current capacity is ensured in a through hole.SOLUTION: A printed circuit board 1 includes a printed wiring board 10 and a current reinforcing member 20 for reinforcing a current capacity of a through hole. The current reinforcing member 20 includes a hollow cylindrical main body portion 21 loosely fitted into the through hole 12 of the printed wiring board 10 with a gap therebetween and an engaging portion 22 protruding from the main body portion 21 and is connected and fixed to a circuit pattern 11 formed on the front and back surfaces of the printed circuit board 1.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a printed circuit board and a printed circuit device having a structure for reinforcing a current capacity of a through hole.

  In recent years, a so-called strong electric circuit (for example, a power supply circuit) in which a large current flows and a so-called weak electric circuit (for example, an LSI) in which signal control is performed on the same substrate due to cost reduction related to the substrate and components. There is a need to implement. The printed circuit board dedicated to the high-power circuit is designed to increase the current capacity in the entire board including the through-hole portion. However, the cost of the printed circuit board itself and the manufacturing cost thereof are increased accordingly. On the other hand, the printed circuit board used in the weak electric circuit is less expensive than the printed circuit board dedicated to the high electric circuit, but the current capacity for mounting the high electric circuit may not be sufficient. In particular, there is a problem in that a sufficient current capacity cannot be secured in the through holes connecting the circuit patterns.

  Specifically, in Patent Document 1, as a general circuit board manufacturing method, a through hole is formed in an insulating resin substrate on which a copper foil is laminated, and a plating film is formed on the inner wall of the through hole and the copper foil. A forming technique is disclosed (see FIGS. 1A to 1D). The plating thickness of the inner wall of the through hole formed by such a method is about several tens of μm, which is not sufficient as a current capacity when a high-power circuit is mounted.

  In view of this, for example, as shown in Patent Document 1, it is conceivable to fill a through hole with a conductive paste to reinforce the current capacity in the through hole portion (see FIGS. 1E to 1F). .

JP 2001-111188 A

  However, when a conductive paste is filled in a through hole, a terminal of an electronic component cannot be inserted into the through hole. Therefore, it is necessary to prepare a through hole for inserting the terminal separately from the one for filling the conductive paste, and there is a problem that the substrate area becomes large. Furthermore, there is also a problem that it is necessary to perform the process of filling the conductive paste separately from the mounting process of electronic components and the like.

  In view of the above problems, an object of the present invention is to solve the above-described problems and provide a printed circuit board in which a current capacity in a through hole is sufficiently secured.

  In one aspect of the present invention, the printed circuit board includes a printed wiring board having a circuit pattern formed on the front and back surfaces and a through hole penetrating in the thickness direction of the board, and a gap between the through hole of the printed wiring board. A hollow cylindrical main body portion that is loosely fitted with a gap, and a locking portion that protrudes from one end portion of the main body portion in the substrate thickness direction along the surface of the printed wiring board. A current reinforcing member, wherein the engaging portion is connected and fixed to a circuit pattern on the surface side of the printed wiring board by a conductive connecting member, and the other end portion of the main body portion is electrically conductive. It is characterized in that it is connected and fixed to the circuit pattern on the back surface side of the printed wiring board by a conductive connecting member.

  Here, in the “through hole”, a through hole in which a conductive film (for example, a plating film) is formed on the inner wall, and a base material of the substrate is exposed as it is without a conductive film formed on the inner wall. And so-called non-through-holes.

  In the printed circuit board according to the above aspect, a hollow cylindrical current reinforcing member provided with a gap between the inner wall of the through hole is attached to the through hole, and the reinforcing member and the circuit pattern are connected and fixed. . Therefore, it is possible to insert a terminal such as an electronic component into the hollow portion. As in the technique disclosed in Patent Document 1, a through hole for inserting a terminal is separated from a through hole for reinforcing current capacity. There is no need to provide it. Therefore, it is possible to prevent the substrate area from increasing due to the reinforcement of the current capacity.

  Furthermore, since the current reinforcing member is loosely fitted in the through hole, the current reinforcing member can be removed from the printed circuit board before and after the connection between the current reinforcing member and the circuit pattern, and it is attached to the same through hole again. Or can be replaced with other through holes. Thereby, according to arrangement | positioning etc. of components, the current capacity concerning a desired through hole can be reinforced afterwards. By enabling such selective reinforcement of current capacity, versatility can be improved and the substrate cost can be reduced.

  A conductive film may be formed on the inner wall of the through hole, and a slit extending along the substrate thickness direction may be formed in the main body portion of the current reinforcing member.

  By providing a slit in the main part of the current reinforcing member, for example, when the fluidity at the time of connecting and fixing the connecting member is high, such as molten solder, the connecting member is easily guided into the through hole along the slit. Become. Thereby, connection stability and connection strength between the conductive film on the inner wall of the through hole and the conductive connection member can be increased.

  The other end portion of the current reinforcing member may protrude outward in the substrate thickness direction from the back surface of the printed wiring board.

  According to this configuration, the reliability of connection between the current reinforcing member and the circuit pattern can be increased, and the connection area can be increased, so that the effect of reinforcing the current capacity can be increased. Moreover, the connection state of a reinforcement member and a circuit pattern can be confirmed visually.

  The engaging portion of the current reinforcing member may have a flat surface on the side opposite to the side facing the circuit pattern.

  According to this configuration, the locking portion has a flat surface on the side opposite to the side facing the circuit pattern, that is, on the outer side in the board thickness direction when the current reinforcing member is mounted on the printed wiring board. The current reinforcing member can be arranged using the same general-purpose mounting apparatus as the component. This eliminates the need to introduce new equipment. On the other hand, for example, when filling the through hole with the conductive paste, a dedicated device for filling the conductive paste is required in addition to the existing production equipment, and the filling process is a separate process from the component mounting. It takes time and effort.

  The latching portion of the current reinforcing member has a plurality of latching portions extending in different directions along the surface of the printed wiring board from one end of the main body, and the plurality of latching portions are conductive. It may be connected and fixed to a circuit pattern on the surface side of the printed wiring board by a connecting member.

  According to this configuration, since the reinforcing member is connected to the circuit pattern at a plurality of different positions, the effect of reinforcing the current capacity and the connection stability can be further improved.

  The locking portion of the current reinforcing member includes a base portion extending toward the outside of the main body portion, and at least one branch portion extending from the base portion in a direction intersecting with the extending direction of the base portion. It is good as well.

  According to this configuration, for example, the length of the side of the current reinforcing member in contact with the circuit pattern can be increased, that is, the connection length by the connecting member at the boundary portion between the circuit pattern and the current reinforcing member is ensured. Can do. Thereby, the connection strength and connection stability of a connection member can be improved more.

  According to the present invention, since the current capacity is reinforced by the current reinforcing member loosely fitted in the through hole of the printed wiring board, the current capacity of the desired through hole can be increased afterwards. Furthermore, the substrate area is not increased by reinforcing the current capacity.

It is a top view showing a schematic structure of a printed circuit device concerning this embodiment. It is a schematic sectional drawing in the XX line of FIG. It is a perspective view which shows schematic structure of an electric current reinforcement member. It is a figure for demonstrating the manufacturing process of the printed circuit device which concerns on this embodiment.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. The following description of the preferred embodiments is merely exemplary in nature and is in no way intended to limit the invention, its application, or its application.

  FIG. 1 is a plan view showing a schematic configuration of a printed circuit device A according to the present embodiment. FIG. 2 is a schematic sectional view taken along line XX of FIG.

  The printed circuit device A includes a printed circuit board 1 and electronic components 30 such as ICs and passive elements mounted on the printed circuit board 1. FIG. 1 shows an example in which the electronic component 30 is mounted on the surface of the printed circuit board 1. In addition, the electronic component 30 may be mounted on one side of the front and back surfaces of the printed circuit board, or may be mounted on both sides. In the present disclosure, the printed circuit device A indicates a state in which the electronic component 30 or the like is mounted on the printed circuit board 1.

  The printed circuit board 1 has a printed wiring board 10 having circuit patterns 11 formed on the front and back surfaces and having through-holes 12 penetrating in the thickness direction of the board, and a current reinforcing member for reinforcing the current capacity of the through-holes 12. 20. In the present disclosure, the printed wiring board 10 refers to a board on which circuit patterns 11 are formed on the front and back surfaces and through holes 12 are formed in the board thickness direction. As shown in FIG. 4A, the printed wiring board 10 does not have the solder plating film 10c formed on the circuit pattern 11 and the inner wall of the through hole 12, that is, the non-through hole as the through hole 12. 4 and the printed wiring board on which the plating film 10c is formed on the circuit pattern 11 and the inner wall of the through hole 12 as shown in FIG. 4B. The printed circuit board 1 refers to a board in which the current reinforcing member 20 is inserted into some or all through holes of the printed wiring board 10 and the current reinforcing member 20 and the circuit pattern 11 are soldered. (See FIG. 4C).

  As shown in FIG. 2, the printed wiring board 10 has a laminated structure in which wiring layers 10a and insulating layers 10b are alternately laminated. FIG. 2 shows an example of a printed wiring board 10 having a four-layer structure. The wiring layer 10a is formed of, for example, copper foil, and the circuit pattern 11 is formed in each wiring layer 10a by etching or the like. In addition, the number of layers of the printed wiring board 10 and the material of the insulating layer and the wiring layer are not particularly limited.

  The printed wiring board 10 is formed with a plurality of through holes 12 for connecting circuit patterns 11 of different wiring layers 10a to each other. A plating film 10 c is formed continuously and integrally on the circuit pattern 11 on the front and back surfaces of the printed wiring board 10 and on the inner wall of the through hole 12. Circuit patterns 11 of different wiring layers 10a are connected to each other by the plating film 10c. 2 and 4 show an example in which the circuit pattern 11 on the front surface of the substrate and the circuit pattern 11 on the back surface of the substrate are connected by the plating film 10c by the plating film 10c. The thickness of copper foil and the plating film 10c is not specifically limited, What is necessary is just to have a thickness comparable as a prior art. Specifically, it is about 15-40 micrometers, for example. For convenience of explanation, in FIG. 1, the front surface in the direction orthogonal to the paper surface is the front surface, and the back surface in the direction orthogonal to the paper surface is not illustrated. Similarly, in FIGS. 2 and 4, the upper surface of the drawing is the front surface, and the lower surface of the drawing is the back surface. However, since the front and back of the printed wiring board 10 and the printed circuit board 1 are not particularly limited in the present disclosure, the front and back may be reversed, and the same effect can be obtained.

  A conductive current reinforcing member 20 is attached to a desired through hole 12 selected from the plurality of through holes 12 from the viewpoint of reinforcing the current capacity. The current reinforcing member 20 includes a hollow cylindrical main body 21 loosely fitted in the through hole 12 with a gap, and one end in the longitudinal direction (substrate thickness direction) of the main body 21 from the circumferential direction outward. And a locking portion 22 that protrudes integrally. Here, “to be loosely fitted” means to be fitted with a play (interval) between the through hole 12 and the main body portion 21 of the current reinforcing member 20. The size of the gap is not particularly limited as long as the circuit pattern 11 and the main body 21 can be soldered.

  As shown in FIG. 3, the main body portion 21 of the current reinforcing member 20 has a hollow cylindrical shape, and the outer diameter in plan view is slightly smaller than the hole diameter of the through hole 12. Thereby, the current reinforcing member 20 is loosely fitted in the through hole 12 with a gap. Further, the current reinforcing member 20 can be attached later to the printed wiring board 10 created by a general-purpose device. That is, the current capacity of the desired through hole 12 can be reinforced afterwards. 2 and 3, 21 a indicates a hollow portion of the main body portion 21.

  In addition, since the shape of the general through hole 12 is circular in a plan view, the shape of the main body portion 21 is assumed to be a hollow cylindrical shape in FIG. 3, but the shape of the main body portion is not particularly limited. For example, you may change according to the shape of a through hole. That is, the term “cylindrical shape” is a concept including a cylindrical shape having a hollow portion 21a and a polygonal shape or an elliptic shape in addition to a cylindrical shape.

  Further, the main body portion 21 is formed with a slit 21b extending over the entire longitudinal direction. By forming such a slit 21b, the solder is easily guided into the through hole 12, and the contact area between the current reinforcing member 20 and the plating film 10c formed on the inner wall of the through hole 12 can be increased. Specifically, for example, when the current reinforcing member 20 is attached to the through hole and then soldered from the back side of the printed wiring board 10 by the flow soldering method, the solder is easily guided into the through hole. Thereby, the connection strength and connection stability between the plating film 10c in the through hole 12 and the current reinforcing member 20 can be enhanced.

  For example, when the current reinforcing member 20 is attached from the surface side of the printed wiring board 10, the locking portion 22 of the current reinforcing member 20 contacts the surface of the printed wiring board 10. This prevents the current reinforcing member 20 from falling off the printed wiring board 10 when the current reinforcing member 20 and the circuit pattern 11 are soldered. After making the above contact state, the locking portion 22 is soldered to the circuit pattern 11. That is, the locking portion 22 may be configured to be locked to the printed wiring board 10 and to be connected and fixed to the circuit pattern 11, and the specific shape is not particularly limited. However, the locking portion 22 is a flat plate from the viewpoint of securing the contact area with the circuit pattern 11 to increase the connection stability and enabling mounting with a general-purpose suction-type component mounting device. desirable. If the latching portion 22 is a flat plate, the latching portion can be adsorbed by the component mounting apparatus, and the current reinforcing member 20 can be attached to the through hole 12. FIGS. 3A to 3C show variations of the configuration of the current reinforcing member 20 having the flat locking portion 22.

  FIG. 3A shows an example in which the locking portion 22 is formed of a rectangular flat plate. FIG. 3B shows an example in which the locking portion 22 is configured by three rectangular flat plates extending in different directions. In FIG.3 (c), the latching | locking part 22 is divided into the base part 22a extended toward the outer side of the main-body part 21, and the some branch part extended and branched from the base part 22a in the direction orthogonal to the direction where the base part 22a is extended. 22b. With such a configuration, the contact portion between the side surrounding the outer periphery of the locking portion 22 and the solder can be increased, so that the soldering is improved and the connection strength between the current reinforcing member 20 and the circuit pattern 11 is improved. And connection stability can be improved. Further, for example, when the current reinforcing member 20 is formed by molding from a flat plate, the current reinforcing member 20 can be realized by folding, and there is a merit that the creation ease is high.

  For example, the locking portion 22 may be composed of two or four or more flat plates, or it may be a circular flat plate. Further, in FIG. 3C, the number of branch portions may be at least one, and the branching direction is not limited to the orthogonal direction. Moreover, you may replace each latching | locking part 22 of FIG.3 (b) with the latching | locking part of FIG.3 (c).

  Further, as shown in FIGS. 3A to 3C, the entire front side of the locking portion 22 does not need to be a flat surface, and if a part of the front side of the locking portion 22 is a flat surface, a general-purpose mounting device is used. The same effect can be obtained. For example, the locking portion 22 may have a rising portion having a shape that rises in the substrate thickness direction at the peripheral portion.

  Further, for example, the locking portion 22 may have a flange shape that extends from the front side end portion of the main body portion toward the outer side in the circumferential direction along the surface of the substrate. Moreover, the latching | locking part 22 may be a rod-shaped thing of a cross-sectional circle or a cross-section rectangle, for example. Then, for example, in the rod-shaped locking portion 22 having a circular cross section, a part of the front side may be cut off in a direction along the substrate surface, and a flat surface may be formed on the front side of the locking portion 22.

  Returning to FIG. 2, the electronic component 30 mounted on the surface of the printed circuit board 1 will be described. As described above, the electronic component 30 can be mounted on either the front or back surface of the printed circuit board 1. The electronic component 30 is attached so that the terminal 31 is inserted through the through hole 12 using a general-purpose mounting device. Here, in the through hole 12 to which the current reinforcing member 20 is attached, the terminal 31 of the electronic component 30 is inserted into the hollow portion 21a of the main body portion 21 of the current reinforcing member 20 and soldered.

  The length of the terminal 31 of the electronic component 30 is not particularly limited. However, the end portion of the terminal 31 of the electronic component 30 is inserted in the direction of insertion of the back surface of the printed wiring board 10 and the current reinforcing member 20 when soldering from the viewpoint of securing the connection strength of soldering and improving the connection stability. It is preferable to protrude from the end on the back side (lower side in FIG. 2).

  Next, a method for manufacturing the printed circuit device A will be described in detail with reference to FIG.

  First, a printed wiring board 10 having four wiring layers 10a as shown in FIG. 4B is prepared. As shown in FIG. 4A, the printed wiring board 10 has through holes 12 formed by drilling or laser processing on the board on which the four wiring layers 10a are formed. It is obtained by forming a plating film 10 c on the circuit pattern 11 and on the inner wall of the through hole 12. The through holes 12 may all have the same hole diameter, or some of them may be different. For example, the hole diameters of all the through holes 12 may be sized so that the current reinforcing member 20 can be loosely fitted with a gap. Further, compared to the through hole 12 in which the current reinforcing member 20 may be inserted, the hole diameter of the through hole 12 arranged at other locations is made small so that at least the terminal of the electronic component can be inserted. It may be. FIG. 1 shows an example in which the size of the through hole 12 into which the current reinforcing member 20 is inserted is slightly different from the size of the other through holes 12.

  Next, the current reinforcing member 20 is inserted from the front side or the back side into the desired through hole 12 for which the current capacity is to be reinforced, and the circuit pattern 11 and the engaging portion 22 formed on the front surface in the insertion direction are soldered. Attach. FIG. 4C shows an example in which the current reinforcing member 20 is inserted from the front side of the printed wiring board 10 and the locking portion 22 is soldered to the circuit pattern 11 on the surface of the printed wiring board 10. The soldering method is not particularly limited. For example, the solder can be fixed to the circuit pattern 11 by a reflow soldering method using cream solder as a conductive connecting member. The conductive connecting member is not limited to solder, and other connecting members may be used, and the same applies to other descriptions in the embodiment.

  Next, as shown in FIG. 4D, the terminal 31 of the electronic component 30 is inserted from the front side in the insertion direction of the current reinforcing member 20 through the hollow portion 21a of the main body 21 of the current reinforcing member 20, and soldering is performed. Attach. The soldering method is not particularly limited, and for example, it can be connected and fixed to the circuit pattern 11 by a flow soldering method using a heating tank in which solder is melted and accommodated. In this way, the printed circuit device A can be obtained.

  As described above, the printed circuit board 1 and the printed circuit device A according to the present embodiment attach the current reinforcing member 20 to the through hole 12 of the printed wiring board 10 and solder the current reinforcing member 20 to the circuit pattern 11. By doing so, the current capacity is reinforced. With such a configuration, it is possible to reinforce the current capacity of the desired through-hole 12 with respect to the printed wiring board 10 created using a general-purpose device and without a special process. become able to. Thereby, the printed circuit board 1 and the printed circuit device A in which a desired current capacity is secured can be obtained while suppressing an increase in the cost of the board itself and the board manufacturing cost. Further, since the location for reinforcing the current capacity can be selected after the completion of the production of the printed wiring board 10, a single printed wiring board can be applied to a plurality of printed circuit devices A having different specifications, thereby improving versatility. Can do. Furthermore, since the place where the current capacity is reinforced can be changed even after the printed circuit board 1 is completed once, it is not necessary to remake the entire printed circuit board when there is a design change.

  In the above embodiment, the plating film 10c is formed on the circuit pattern 11 of the printed wiring board 10 and on the inner wall of the through hole 12. However, the through hole (so-called non-hole) in which the plating film 10c is not formed is described. The technique of the present disclosure can also be applied to the printed wiring board 10 in which the through holes are formed, and the same effect can be obtained.

  Specifically, the current reinforcing member 20 may be mounted on the printed wiring board 10 of FIG. 4A, and the same effect is obtained. In the manufacturing method of the printed circuit device A in this case, first, the printed wiring board 10 shown in FIG. Next, the current reinforcing member 20 is inserted from the front side or the back side into the desired through hole 12 for which the current capacity is to be reinforced, and the circuit pattern 11 and the engaging portion 22 formed on the front surface in the insertion direction are soldered. Attach. Further, the terminal 31 of the electronic component 30 is inserted through the hollow portion 21a of the main body portion 21 of the current reinforcing member 20 from the front side in the insertion direction of the current reinforcing member 20 (the front side in FIG. 4). 20 is soldered to the circuit pattern 11 formed on the back side in the insertion direction of the printed wiring board 10 (the back side in FIG. 4). That is, the printed circuit device A can be manufactured by performing the same steps as those in FIGS. 4C and 4D after FIG.

  FIG. 1 shows an example in which different types of current reinforcing members 20 are mounted on the same printed wiring board 10, but even if a common current reinforcing member 20 is mounted on the entire printed wiring board 10. Good. By using the current reinforcing member 20 in common, the labor of the operation is reduced and the part cost can be reduced.

  1 and 3 show an example in which the slit 21b is formed in the main body 21 of the current reinforcing member 20, but a sufficient current capacity can be obtained even if the slit 21b is not formed in the main body 21. The reinforcing effect is obtained.

  The present invention is extremely useful because the current capacity of a desired through hole can be increased afterwards.

A printed circuit device 1 printed circuit board 10 printed wiring board 11 circuit pattern 12 through hole 20 current reinforcing member 21 body part 21b slit 22 locking part 22a base part 22b branch part 30 electronic component 31 terminal

Claims (7)

A printed wiring board in which a circuit pattern is formed on the front and back surfaces and a through hole penetrating in the board thickness direction is formed;
A hollow cylindrical main body part loosely fitted in a through hole of the printed wiring board with a gap, and projecting from one end of the main body part in the board thickness direction along the surface of the printed wiring board A conductive current reinforcing member having a locking portion;
In the current reinforcing member, the locking portion is connected and fixed to a circuit pattern on the surface side of the printed wiring board by a conductive connecting member, and the other end portion of the main body portion is connected to the printed circuit board by a conductive connecting member. A printed circuit board, wherein the printed circuit board is fixedly connected to a circuit pattern on the back side of the wiring board. The printed circuit board according to claim 1,
A conductive film is formed on the inner wall of the through hole,
The printed circuit board according to claim 1, wherein a slit extending along a thickness direction of the board is formed in the main body of the current reinforcing member. The printed circuit board according to claim 1 or 2,
The printed circuit board according to claim 1, wherein the other end portion of the current reinforcing member protrudes outward in the substrate thickness direction from the back surface of the printed wiring board. The printed circuit board according to any one of claims 1 to 3,
The printed circuit board according to claim 1, wherein the engaging portion of the current reinforcing member has a flat surface on a side opposite to the side facing the circuit pattern. The printed circuit board according to any one of claims 1 to 4,
The latching portion of the current reinforcing member has a plurality of latching portions extending in different directions along the surface of the printed wiring board from one end of the main body, and the plurality of latching portions are conductive. A printed circuit board, wherein the printed circuit board is connected and fixed to a circuit pattern on the surface side of the printed wiring board by a connecting member. The printed circuit board according to any one of claims 1 to 5,
The locking portion of the current reinforcing member includes a base portion extending toward the outside of the main body portion, and at least one branch portion extending from the base portion in a direction intersecting with the extending direction of the base portion. A printed circuit board. A printed circuit device in which an electronic component is mounted on at least a surface of the printed circuit board according to any one of claims 1 to 6,
The terminal of the electronic component is inserted so that the tip protrudes from the back surface of the printed circuit board through the hollow portion of the main body of the current reinforcing member,
A printed circuit device, wherein the other end of the main body of the current reinforcing member, the circuit pattern on the back side of the printed wiring board, and the terminals of the electronic component are connected and fixed by a conductive connecting member.

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