JP2009295812A - Electronic component mounting substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the occurrence of faults of an electronic component mounting substrate, such as the occurrence of a pin hole in a joint part, due to expansion of air in an through-hole in an electronic component mounting substrate wherein the lower end of an electronic component is brought into close contact with a circuit board and the lead terminal 12 of the electronic component and the through-hole of the circuit board are electrically connected. <P>SOLUTION: The electronic component mounting substrate 1 wherein the mounting surface 3 of a circuit board 21 and the lower end 13 of an electronic component 11 are brought into close contact with each other to cover the mounting surface side of the through-hole 24 with the electronic component 11, includes a communication path 2 enabling air to flow into and out of an end on the mounting surface side of the through-hole 24. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electronic component mounting board for soldering an electronic component to a circuit board.

In a circuit board such as a printed wiring board, an electronic component is mounted by fitting a lead terminal of the electronic component into a through hole formed on the circuit board, and the through hole and the terminal wiring are fixed by soldering or the like ( For example, see Patent Document 1 below). As shown in Patent Document 1, the lower end portion of an electronic component is generally attached separately from a circuit board.
JP 2006-278930 A

  However, if the lead terminal and the through hole are joined by separating the lower end of the electronic component from the mounting surface of the circuit board, if the electronic component has a certain amount of weight, a load or vibration is applied to the joint, and the joint is cracked. As a result, bonding reliability may be reduced.

  On the other hand, if the lower end of the electronic component is mounted in close contact with the mounting surface in order to reduce the load or vibration on the joint, the air escape path in the through hole is blocked. As a result, when soldering or the like is performed from the surface opposite to the contact surface, the air in the through hole expands, and there is a risk that the joint reliability may be reduced due to the occurrence of cracks or pinholes in the joint portion. It was.

  The present invention has been made in view of the above problems, and provides an electronic component mounting board capable of improving the bonding reliability between a through hole and a lead terminal.

  According to the first aspect of the present invention, a circuit board including a conductive layer serving as a wiring pattern, a register layer that covers the conductive layer with an insulating material, and a through hole that is electrically connected to the conductive layer is electrically joined to the through hole. In an electronic component mounting circuit including a lead terminal protruding downward, the mounting surface of the circuit board and the lower end of the electronic component are in close contact, and the electronic component covers the mounting surface side of the through hole. Thus, a communication path through which air can flow in and out is formed at the end of the through hole on the mounting surface side.

  According to the present invention, the air expanded in the through hole can be discharged through the communication path. As a result, the solder joint reliability due to the occurrence of pinholes can be improved.

  In the invention according to claim 2, the communication path is formed by being sandwiched between a groove portion and a lower end portion formed on the circuit board on the mounting surface side, and one end of the communication path communicates with the through hole, The other end is located outside the outer edge of the lower end portion.

  According to the present invention, since the groove portion communicates directly with the through hole, the air expanded in the through hole can be efficiently diffused to the outside.

  In the invention described in claim 3, the lead terminal protrudes from the recess surrounded by the lower end portion, and the communication path is formed by being sandwiched between the groove portion and the lower end portion formed on the circuit board on the mounting surface side. One end of the passage is located inside the inner edge of the lower end portion, and the other end of the communication passage is located outside the outer edge of the lower end portion.

  According to the present invention, one end of the communication path is located inside the inner edge of the lower end, and the other end of the communication path is located outside the outer edge of the lower end, so that the distance of the communication path is minimized. can do.

  In the invention according to claim 4, the communication path is formed by the convex portion provided on the circuit board on the mounting surface side being in close contact with the lower end portion and forming a gap between the lower end portion and the circuit board. It is characterized by that.

  According to the present invention, by providing the convex portion on the surface of the mounting surface, the gap is formed between the lower end portion and the mounting surface. For this reason, a communicating path can be formed flexibly and easily even in a structure in which a groove portion cannot be formed in a register layer or a conductive layer.

  The invention according to claim 5 is characterized in that the convex portion is formed from a silk print layer.

  According to the present invention, since the convex portion is formed by the silk print layer generally used for the circuit board, the convex portion can be formed easily and at low cost.

  According to a sixth aspect of the present invention, the lead terminal protrudes from the recess surrounded by the lower end portion, and the communication path is at a position facing the recess and is formed by penetrating from one surface of the circuit board to the other surface. It is characterized by that.

  According to the present invention, since the communication path is formed on the mounting surface facing the recess, the communication path serving as an air outflow inlet is formed without reducing the contact area between the lower end and the electronic component. Therefore, stable electronic components can be mounted on the circuit board.

(Example 1)
1A is a side view and FIG. 2B is a bottom view of an electronic component 11 (electrolytic capacitor) according to a first embodiment of the present invention, and FIG. 2 is a top view of a circuit board 21 according to the first embodiment of the present invention. FIG. 3 shows a longitudinal sectional view of the electronic component mounting board 1 according to the first embodiment of the present invention. The longitudinal sectional view of FIG. 3 is a view as seen from a plane that passes through a pair of through holes and is perpendicular to the paper surface.

  The electronic component mounting board 1 mainly includes an electronic component 11 and a circuit board 21.

  A lead terminal 12 protrudes from the electronic component 11. In the case of FIG. 1, the lead terminal 12 protrudes from the lower end portion 13 of the electronic component 11. Here, when the electronic component 11 is mounted on the circuit board 21, the lower end 13 has a role of supporting the electronic component 11 by being in close contact with the circuit board 21, but a portion that is not in close contact is also included in the lower end 13. . Examples of the electronic component 11 used in the present invention include an electrolytic capacitor. The electronic component 11 is particularly effective when the electronic component 11 is so heavy that the lead terminal 12 cannot support the electronic component 11 when the bottom of the electronic component 11 is placed away from the circuit board 21. This is because if the configuration of the present invention is used, the weight of the electronic component 11 can be supported not only by the lead terminals but also by the lower end portion 13 and the communication path 2 can escape air. As a result, it is possible to prevent the occurrence of cracks and pinholes in the joint portion 5 joined by the solder of the lead terminal 12 and the through hole 24 by the weight of the electronic component 11 or air sealed in the through hole.

  The circuit board 21 includes a conductive layer 22 serving as a wiring pattern and a register layer 23 that covers the conductive layer 22 with an insulating material. The circuit board 21 is electrically connected to the conductive layer 22 and penetrates from one surface of the circuit board 21 to the other surface direction. A through-hole 24 is provided. The circuit board 21 has a groove 25 that communicates with the through hole 24. The through hole 24 is provided at a position where the lead terminal 12 of the electronic component 11 is electrically connected by soldering or the like.

  In the electronic component mounting board 1, the mounting surface 3 of the circuit board 21 and the lower end portion 13 of the electronic component 11 are in close contact, and the electronic component 11 is mounted so as to cover the mounting surface side of the through hole 24. Here, the mounting surface 3 is an upper surface portion of the circuit board that is in close contact with the lower end portion 3 of the electronic component 11 when the electronic component 11 is mounted on the circuit board 21. The lead terminal 12 and the through hole 24 are electrically and physically joined by the joining portion 5. As a joining method, for example, there is soldering, and the through hole 24 and the lead terminal 12 are joined by solder in a state where the lead terminal 12 led out from the electronic part of the electronic component 11 is attached to the through hole 24 of the circuit board 21. It is formed by doing. Soldering is to join a metal or an electronic component 11 by melting solder with heat.

  The electronic component mounting substrate 1 forms a communication path 2 through which air can flow in and out of the end of the through hole 24 on the mounting surface side. The communication path 2 is formed by being sandwiched between the groove 25 formed on the circuit board on the mounting surface side and the lower end 13 of the electronic component 11. When the lower end portion 13 of the electronic component 11 is in close contact with the mounting surface 3 of the circuit board 21, the groove portion 25 becomes the side surface and the bottom surface of the communication path 2, and the lower end portion 13 becomes the upper surface of the communication path 2. One end 26 of the communication path 2 communicates with the through hole 24, and the other end 27 of the communication path 2 is located outside the outer edge 29 of the lower end portion 13 of the electronic component 11. As a result, even if soldering is performed from the opposite side of the mounting surface 3 and the air in the through hole 24 expands, the air flows out from the communication path 2. Therefore, it is possible to prevent a situation in which pinholes are generated in the solder or a substrate is damaged due to the expansion of air.

  The communication path 2 can be formed by removing the conductive layer 22 made of copper foil or the like and the register layer 23 made of an insulating material in a portion where the bottom of the electronic component and the circuit board 21 overlap each other.

  When the electronic component 11 has a pair of lead terminals 12, the circuit board 21 is also provided with a pair of through holes 24. In such a case, it is desirable to provide the communication path 2 on substantially the same straight line as the through hole 24. For example, when a pair of through-holes 2 is formed and a straight line connecting the pair of through-holes 2 and a straight line connecting the pair of through-holes are formed so as to intersect substantially vertically when viewed from above, This is because the mounting of the electronic component 11 on the circuit board is not stable, and the mounting of the electronic component is difficult to stabilize.

  Further, it is preferable to provide the communication path 2 at a location where the distance between the through hole 24 and the outer edge 29 of the lower end surface 13 is the shortest. It is because the distance of the communication path 2 can be shortened and the inflow / outflow amount of air can be increased.

(Example 2)
4A is a side view and FIG. 5B is a bottom view of the electronic component 11 (electrolytic capacitor) according to the second embodiment of the present invention, and FIG. 5 is a top view of the circuit board 21 according to the second embodiment of the present invention. 6 shows a longitudinal sectional view of the electronic component mounting board 1 according to the second embodiment of the present invention. The longitudinal cross-sectional view of FIG. 6 is a view seen from a plane that passes through a pair of through holes and is perpendicular to the paper surface.

  As for the electronic component 11, the sleeve of the exterior material which consists of vinyl etc. is used as the exterior of the electronic component 11 (electrolytic capacitor), and the outer periphery of the bottom face in the electronic component 11 is covered with the sleeve. Therefore, the sleeve portion 14 on the bottom surface of the electronic component 11 becomes the lower end portion 13, and the lead terminal 12 protrudes from the concave portion 15 surrounded by the lower end portion 13 (sleeve portion 14).

  In the communication path 2 formed in the circuit board 21, one end 26 is located inside the inner edge 28 of the lower end portion 13, and the other end 27 is located outside the outer edge 29 of the lower end portion 13. Unlike the case of the first embodiment, since the gap portion 4 is formed between the protrusion 17 of the lead terminal 12 and the mounting surface 3, one end 26 of the groove 25 serving as the communication path 2 is the inner edge 28 of the lower end portion 13. If it is formed so as to be located on the inner side and the other end 27 to be located on the outer side of the outer edge 29 of the lower end portion 13, sufficient air can escape to the outside of the gap portion 4. Even when the lead terminal 12 protrudes from the recess 15, the groove 25 (communication path 2) may be formed so as to communicate from the through hole 24 to the outside of the outer edge 29 as in the first embodiment.

(Example 3)
FIG. 7 shows a top view of a circuit board according to Embodiment 3 of the present invention, and FIG. 8 shows a longitudinal sectional view of the electronic component mounting board 1 according to Embodiment 3 of the present invention. The longitudinal cross-sectional view of FIG. 8 is a view seen from a plane that passes through a pair of through holes and is perpendicular to the paper surface. The electronic component 11 used in the third embodiment may be the electronic component 11 in which the lead terminal 12 protrudes from the lower end portion 13 as shown in FIG. 1, or the electronic component 11 in which the lead terminal 12 protrudes from the recess 15 as shown in FIG. .

  The circuit board 21 according to the third embodiment has a convex portion 30 provided on the circuit board on the mounting surface side, and the lower end portion 13 and the convex portion 30 are brought into close contact with each other so that the lower end portion 13 and the circuit board 21 A gap 4 is generated between them. The gap 4 serves as the communication passage 2 and allows air to flow in and out. As a method of forming the convex portion 30, for example, a method using a silk print layer can be considered. Silk printing is generally used to display a position where the electronic component 11 is attached, and can be easily and easily manufactured by forming the protrusion 30 by using silk printing generally used for the circuit board 21. .

(Example 4)
FIG. 9 is a top view of the circuit board 21 according to the fourth embodiment of the present invention, and FIG. 10 is a vertical cross-sectional view of the electronic circuit mounting board according to the fourth embodiment of the present invention. The longitudinal cross-sectional view of FIG. 10 is a view seen from a plane that passes through a pair of through holes and is perpendicular to the paper surface. The electronic component 11 used in Example 4 is the same as that shown in FIG. The communication path 2 formed in the electronic component mounting substrate 1 is in a position facing the recess 16, and the communication path 2 penetrates from one surface of the circuit board 21 to the other surface. The through hole 24 and the communication path 2 are connected via a hollow portion formed between the recess 15 of the electronic component 11 and the circuit board 21, and the air in the through hole 24 flows out to the outside through the communication path 2. The

(Example 5)
FIG. 11 shows a top view of a circuit board 21 according to the fifth embodiment of the present invention. The fifth embodiment is a modification of the fourth embodiment. Similar to the fourth embodiment, the electronic component uses a lead terminal protruding from the recess. The communication path in the electronic component mounting circuit is at a position facing the recess and is formed so as to penetrate from one surface of the circuit board to the other surface.

  The electrical connection between the lead terminal 12 and the through hole 24 is performed by jet soldering in which jet solder that blows upward from the jet solder layer is brought into contact with the lower surface of the circuit board 21, and the jet solder adheres to the circuit board 21. When the solder contact surface 31 is provided, the communication path is formed between the solder contact surface 31 and the inner edge 28 of the lower end portion 13. When jet soldering is performed, if the communication path 2 is formed on the solder contact surface 31, the communication path 2 is blocked by the solder. Therefore, in order to prevent such a situation, the solder contact surface 31 and the inner edge 28 of the lower end portion 13 A communication passage 2 is formed between them. Specifically, the place where the distance between the through hole and the through hole 24 is the longest is ideal. As shown in FIG. 4, when two or more through holes 24 are formed in the recess 15, it is desirable to provide a through hole at a position where the distance between the through hole and the nearest through hole 24 is maximum.

It is (a) side view and (b) bottom view of the electronic component (electrolytic capacitor) which concerns on Example 1 of this invention. It is a top view of the circuit board concerning Example 1 of the present invention. It is a longitudinal cross-sectional view of the electronic component mounting circuit which concerns on Example 1 of this invention. It is (a) side view and (b) bottom view of the electronic component (electrolytic capacitor) which concerns on Example 2 of this invention. It is a top view of the circuit board concerning Example 2 of the present invention. It is a longitudinal cross-sectional view of the electronic component mounting circuit which concerns on Example 2 of this invention. It is a top view of the circuit board concerning Example 3 of the present invention. It is a longitudinal cross-sectional view of the electronic component mounting circuit which concerns on Example 3 of this invention. It is a top view of the circuit board concerning Example 4 of the present invention. It is a longitudinal section of an electronic circuit mounting board concerning Example 4 of the present invention. It is a top view of the circuit board concerning Example 5 of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic component mounting board 2 Communication path 3 Mounting surface 4 Gap part 5 Joint part 11 Electronic component 12 Lead terminal 13 Lower end part 14 Sleeve part 16 Recessed part 17 Projection origin 21 Circuit board 22 Conductive layer 23 Register layer 24 Through hole 25 Groove part 26 One end 27 Other end 28 Inner edge 29 Outer edge 30 Convex part 31 Solder bonding surface

Claims (6)

A circuit board including a conductive layer serving as a wiring pattern, a register layer covering the conductive layer with an insulating material, and a through hole electrically connected to the conductive layer, and a lead terminal electrically connected to the through hole are provided below An electronic component mounting circuit comprising:
The mounting surface of the circuit board and the lower end portion of the electronic component are in close contact, and the electronic component covers the mounting surface side of the through hole, and air is attached to the end portion of the through hole on the mounting surface side. An electronic component mounting board characterized in that a communication path capable of flowing in and out is formed.   The communication path is formed by being sandwiched between a groove formed on the circuit board on the mounting surface side and the lower end, and one end of the communication path communicates with the through hole, and the other end of the communication path The electronic component mounting board according to claim 1, wherein the electronic component mounting board is positioned outside an outer edge of the lower end portion.   The lead terminal protrudes from a recess surrounded by the lower end, and the communication path is formed by being sandwiched between a groove formed on the circuit board on the mounting surface side and the lower end, 2. The electronic component mounting board according to claim 1, wherein one end is located inside an inner edge of the lower end portion, and the other end of the communication path is located outside an outer edge of the lower end portion.   The communication path is formed such that a convex portion provided on the circuit board on the mounting surface side is in close contact with the lower end portion, and a gap is formed between the lower end portion and the circuit board. The electronic component mounting board according to claim 1, wherein   The electronic component mounting board according to claim 4, wherein the convex portion is formed of a silk print layer. The lead terminal protrudes from a recess surrounded by the lower end,
The electronic component mounting board according to claim 1, wherein the communication path is located at a position facing the concave portion and is formed by penetrating from one surface of the circuit board to the other surface.

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