JP5920634B2 - Printed board - Google Patents

Description

  The present invention relates to a printed circuit board on which a heat generating component is mounted and a heat dissipation structure for the heat generating component.

  2. Description of the Related Art Conventionally, in a printed circuit board used in an electric junction box of an automobile, for example, as described in Japanese Patent Application Laid-Open No. 2005-260159 (Patent Document 1), when a heat generating component is mounted on the printed circuit board, a heat radiating conductor is used. A pattern is disposed on a large area of a printed circuit board. In addition, since the grounding conductor is required to reduce resistance and improve heat dissipation, the grounding conductor is often provided so as to cover a wide area of the surface of the printed circuit board also serving as a heat dissipation conductor pattern.

  However, when the heat dissipating conductor pattern and the grounding conductor are set in a wide range on the printed circuit board as described above, the usable range of the printed circuit board is narrowed, and the design flexibility is reduced. In particular, in response to the recent demands for miniaturization and space saving, the space for disposing the heat dissipating conductor pattern has been limited, and there has been a problem that setting of the heat dissipating conductor pattern is becoming difficult. .

  In order to improve this point, for example, it is conceivable to increase the thickness of the copper foil of the ground pattern. However, this is not a preferable solution in terms of an increase in cost and difficulty in fine processing. Further, for example, it is also possible to newly attach a heat dissipating fin-shaped heat dissipating component to an electronic component that is a heating element, such as a circuit board described in Japanese Patent Application Laid-Open No. 2006-156503 (Patent Document 2). However, this is not a preferable solution from the viewpoint of cost and workability.

JP 2005-260159 A JP 2006-156503 A

  The present invention has been made in the background of the above-mentioned circumstances, and its solution is to provide a printed circuit board having a novel structure that can improve the heat dissipation effect without increasing the conductive pattern for heat dissipation. There is to do.

  Hereinafter, embodiments of the present invention made to solve the above-described problems will be described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible.

  According to a first aspect of the present invention, in a printed board on which a heat generating component is mounted, a board connector having a plurality of connection terminals is mounted, and the heat generating component is connected to a heat radiating conductor pattern. On the other hand, the plurality of connection terminals of the board connector include a heat radiation dummy terminal that is connected to the heat radiation conductor pattern but is not connected to the mating connector terminal.

  According to this aspect, the connection terminal is used as a heat radiation dummy terminal by using the connection terminal that is not connected to the mating connector terminal in the board connector and connecting the connection terminal to the heat radiation conductor pattern connected to the heat generating component. It is possible to provide a completely new heat dissipating structure that can be realized. Since the heat radiation dummy terminal is connected to the heat radiation conductor pattern, the heat radiation effect can be improved by utilizing the heat radiation performance of the heat radiation dummy terminal (connection terminal). The arrangement area can be reduced, and the space efficiency of the printed circuit board can be improved at the same time.

  In particular, since the heat dissipation structure of this aspect can be realized simply by using the connection terminals of the board connector mounted on the printed circuit board as dummy terminals for heat dissipation, it can be handled with existing equipment, increasing costs, deteriorating workability, etc. The problem does not occur. Note that the heat radiation dummy terminal may be provided exclusively for the board connector, but the board connector often generates a so-called empty terminal that is unused. Therefore, by using an unused board terminal as a dummy terminal for heat dissipation, it is possible to further reduce costs and improve space efficiency.

  Also, the number of dummy terminals for heat dissipation can be arbitrarily set according to the empty space, the number of unused terminals, required heat dissipation characteristics, and the like, and may be one or plural.

  According to a second aspect of the present invention, in the one described in the first aspect, the plurality of connection terminals of the board connector include a grounding terminal, and the grounding terminal serves as the heat dissipating conductor pattern. By being connected, the heat dissipating conductor pattern is used as a grounding conductor.

  According to this aspect, since the wide grounding conductor can be configured using the heat dissipating conductor pattern set relatively wide, the impedance of the grounding conductor can be advantageously reduced, and noise countermeasures can be achieved. The stability and the like can be advantageously ensured.

  A third aspect of the present invention is the one described in the first or second aspect, wherein the heat radiation dummy terminal includes a metal having a heat radiation property equal to or higher than copper. Is.

  According to this aspect, since the dummy terminal for heat dissipation is configured to include a metal having a heat dissipation property equal to or higher than copper, a high heat dissipation effect utilizing the heat dissipation effect of these metals can be obtained, Further reduction of the heat dissipating conductor pattern can be achieved. In addition, since the heat radiation dummy terminal is not connected to the mating connector terminal, the strength is not required so much. For this reason, it is possible to use silver, which is softer than copper but has higher heat dissipation, with an emphasis on heat dissipation.

  According to a fourth aspect of the present invention, in the one described in any one of the first to third aspects, the heat generating component and the board connector are disposed adjacent to each other without interposing another mounting component therebetween. It is what has been.

  According to this aspect, the distance between the heat-generating component connected to the heat-dissipating conductor pattern and the heat-dissipating dummy terminal can be shortened by bringing the heat-generating component and the board connector close to each other. The effect can be utilized more advantageously.

  In the present invention, by using a connection terminal that is not connected to the mating connector terminal in the board connector, the connection terminal can be used as a heat dissipation dummy terminal by connecting the connection terminal to the heat dissipation conductor pattern connected to the heat generating component. Thus, it is possible to provide a completely new heat dissipation structure that has never existed. Therefore, the heat dissipation effect can be improved, and the arrangement area of the heat dissipating conductor pattern can be reduced correspondingly. Therefore, the space efficiency of the printed circuit board can be improved at the same time. And since it can implement | achieve only by utilizing the connection terminal of a board | substrate connector as a dummy terminal for heat radiation, it can respond with the existing equipment, and problems, such as a cost increase and workability deterioration, do not generate | occur | produce.

The top view of the printed circuit board as one embodiment of the present invention. The bottom view of the printed circuit board shown in FIG. The III-III cross-sectional enlarged view of FIG. The IV-IV cross-sectional enlarged view of FIG.

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

  First, the printed circuit board 10 as one Embodiment of this invention is shown in FIGS. The printed circuit board 10 includes a substantially rectangular flat plate-shaped insulating substrate 12 made of a known insulating material such as a glass epoxy resin, solid patterns 18 and 20 that are conductor patterns provided on the front surface 14 and the back surface 16 thereof, and wiring. The pattern 22 is configured to include a via hole 24 and a through hole 26 that connect the conductor patterns provided on the front surface 14 and the back surface 16 to each other. On the conductor pattern, an integrated circuit 28, which is an electronic component, a chip capacitor 30, a chip resistor 32, an electrolytic capacitor 34, and a board connector 36 are mounted. In order to facilitate understanding, in FIGS. 1 and 2, the electronic component and the board connector 36 are drawn with phantom lines, whereas in FIGS. 1 to 4, solder is not shown. Further, in the following description, “upper” refers to the upper side in FIG. 1, “lower” refers to the lower side in FIG. 1, and “left” refers to the left in FIG. 1, and “right” refers to the right in FIG. To say better.

  As shown in FIG. 1, the solid patterns 18 and 20, which are conductive patterns for heat dissipation, are conductor patterns formed so as to cover the front surface 14 and the back surface 16 of the printed circuit board 10 with a considerably larger area than the wiring pattern 22. It is usually connected to a power source, ground, or wiring for a large current circuit, and is used for reducing resistance and improving heat dissipation. Further, for the solid patterns 18 and 20, a copper foil having a nominal thickness of 35 μm or 70 μm is usually used, but a thicker copper foil having a nominal thickness of 210 μm may be used. This copper foil thickness is arbitrarily set according to the standard of the wiring pattern 22 which is a conductor pattern excluding the solid patterns 18 and 20 such as a desired current value. Further, the solid patterns 18 and 20 are connected to each other by a large number of via holes 24 penetrating the printed board 10. The via hole 24 has a structure in which a conductor such as solder is embedded in the hole, and the solid patterns 18 and 20 are connected to each other with low resistance. As described above, in this embodiment, the front surface 14 and the back surface 16 of the printed circuit board 10 are provided with the solid patterns 18 and 20 having substantially the same shape and connected to each other, so that either the front surface 14 or the back surface 16 can be connected. Compared to the case where it is provided only on one surface, it is expected that the effect will be approximately doubled for the reduction of resistance and the improvement of heat dissipation.

  On one side 38 of the solid pattern 18 provided on the surface 14 of the printed board 10, an integrated circuit 28 that is a heat generating component is mounted. More specifically, the integrated circuit 28 is configured to include an integrated circuit body 40 and a plurality of surface mounting terminals 42, and the back surface of the integrated circuit body 40 is substantially as shown in FIG. A ground electrode 44 is provided over the entire surface. The ground electrode 44 is connected to one side 38 of the solid pattern 18 by soldering. Thereby, the heat generated in the integrated circuit 28 can be efficiently released onto the solid pattern 18 through the ground electrode 44 having a large area provided on the back surface. A plurality of thermal gap portions 46 are formed around the solid pattern 18 to which the integrated circuit body 40 is soldered. The thermal gap 46 is provided to prevent a problem that soldering becomes difficult due to heat spreading to the solid pattern 18 around the integrated circuit body 40 and escaping during soldering. . In addition, as shown in FIG. 3, the plurality of surface mounting terminals 42 provided on the integrated circuit 28 protrude in a crank shape vertically outward from the right side surface of the integrated circuit body 40. The tip portion of the wiring pattern 22 is placed on a pad portion 48 provided on the wiring pattern 22. As shown in FIG. 1, the pad portion 48 is wider than the wiring pattern 22, and is configured with an area sufficient for mounting the surface mounting terminals 42. The surface mounting terminals 42 are connected to the wiring pattern 22 by being soldered to the pad portions 48.

  On the other hand, as shown in FIG. 1, a board connector 36 having a plurality of connection terminals 52 is mounted on the other side 50 of the solid pattern 18 provided on the surface 14 of the printed board 10. Yes. More specifically, the board connector 36 has eight connection terminals 52, of which three connection terminals 52 are inserted into the through holes 26 provided on the solid pattern 18, while the remaining Five connection terminals 52 are inserted into the through holes 26 provided outside the area of the solid pattern 18. Then, by soldering the connection terminals 52 to the through holes 26, the three connection terminals 52 are connected to the solid pattern 18, and two of the remaining five connection terminals 52 are connected to the through hole 26. The wiring pattern 22 is connected. As shown in FIGS. 1 and 2, a plurality of thermal gap portions 53 are also formed in the peripheral portion of the through hole 26 to be soldered to the solid patterns 18 and 20. The thermal gap portion 53 is also provided to prevent the problem that soldering becomes difficult due to heat spreading to the solid patterns 18 and 20 around the through hole 26 and escaping during soldering. is there.

  As shown in FIGS. 1 and 4, among the four connection terminals 52a, 52b, 52c, 52d provided on the right side of the board connector 36, the upper three connection terminals 52a, 52b in FIG. , 52 c are connected to the solid pattern 18, while the lowermost connection terminal 52 d is connected to the wiring pattern 22. As shown in FIG. 1, the board connector 36 has a substantially rectangular parallelepiped shape extending in the vertical direction, and eight connection terminal accommodating portions 54 corresponding to the eight connection terminals 52 are provided in substantially the same shape. ing. As shown in FIG. 3, the connection terminal accommodating portion 54 has a substantially bottomed cylindrical shape that opens to one side. The left and right end portions of the bottom portion 56 of the board connector 36 have leg portions 58 projecting downward, and the leg portions 58 abut against the surface 14 of the printed board 10 when mounted on the printed board 10. So that it can be stably fixed. The connection terminal 52 has a rod shape with both ends tapered, and one side 60 is accommodated so as not to protrude from the opening side of the connection terminal accommodation part 54, while the other side 62 is for the substrate. The bottom portion 56 of the connector 36 is inserted into the through hole 26 of the printed board 10. The board connector 36 is integrally formed by injection molding or the like by molding the connection terminal 52 with a synthetic resin such as polypropylene (PP) or polyamide (PA). The connection terminal 52 is made of, for example, copper or a copper alloy.

  As shown in FIG. 4, one of the connection terminals 52a, 52b, and 52c connected to the solid pattern 18 is connected to the other connector terminal 64 from one side 60 to one connection terminal 52a. The remaining two connection terminals 52b and 52c are heat radiation dummy terminals to which the counterpart connector terminal 64 is not connected. The mating connector terminal 64 is a metal cylinder in which a grounding electric wire 66 is crimped and fixed on one side, and is fixed by fitting the opening 68 into the connection terminal 52a accommodated in the connection terminal accommodating portion 54. Connected. In the present embodiment, the connection terminal 52a of the board connector 36 is a grounding terminal, and the grounding terminal is connected to the solid pattern 18 which is a heat dissipating conductor pattern. It has come to be used as. Further, a mating connector terminal 72 connected to the power supply wire 70 is connected from one side 60 to the connection terminal 52d.

  As shown in FIG. 1, the integrated circuit 28 and the board connector 36 are arranged adjacent to each other, but no other mounting parts are interposed therebetween. As shown in FIGS. 1 and 2, the chip capacitor 30, the chip resistor 32, and the electrolytic capacitor 34, which are electronic components other than the integrated circuit 28, are all pad portions 48 provided in the wiring pattern 22. It has a structure in which both end portions are placed on the top, and is connected to the wiring pattern 22 by being soldered to the pad portion 48. The chip resistor 32 is connected to the wiring pattern 22 provided on the back surface 16 of the printed circuit board 10. For example, the same chip resistor 32 is provided and the number of chip resistors 32 is selected. It is possible to make adjustments so that desired circuit performance is obtained.

  Finally, an example of a soldering method for the printed circuit board 10 having such a configuration will be briefly described. First, solder is printed on the conductor pattern on the surface 14 of the printed board 10 to be soldered, and the integrated circuit 28, the chip capacitor 30, and the electrolytic capacitor 34 are placed on the solder. Then, soldering is performed by melting the solder by a reflow method. Next, the chip resistor 32 mounted on the back surface 16 is fixed at a predetermined position with an adhesive. Further, the board connector 36 is inserted into the through hole 26 and fixed. In this state, the front surface 14 of the printed circuit board 10 is used as a component mounting surface, the back surface 16 is used as a soldering surface, solder is filled into the through holes 26 by a flow method, and the connection terminals 52 and the solid patterns 18 and 20 are soldered. The chip resistor 32 and the pad portion 48 of the wiring pattern 22 are soldered. The soldering is completed by the above operation.

  According to the printed circuit board 10 having such a structure, the connection terminals 52b and 52c that are not connected to the counterpart connector terminal 64 are connected to the integrated circuit 28 that is a heat-generating component, and the solid patterns 18 and 20 that are the heat-dissipating conductor patterns. By connecting to, it is possible to provide a completely new heat dissipating structure that has never been used so that the connection terminals 52b and 52c can be used as heat dissipating dummy terminals. Moreover, since the connection terminals 52b and 52c are connected to the solid patterns 18 and 20, the heat dissipation effect can be improved by utilizing the heat dissipation of the connection terminals 52b and 52c. Therefore, the arrangement area of the solid patterns 18 and 20 can be reduced accordingly, and the space efficiency of the printed circuit board 10 can be improved at the same time.

  In particular, the heat dissipation structure of the present embodiment can be realized only by using the connection terminal 52 of the board connector 36 mounted on the printed board 10 as a heat dissipation dummy terminal. Therefore, existing equipment can be used, and problems such as cost increase and workability deterioration do not occur. In particular, in the present embodiment, since the unused connection terminals 52b and 52c are used as the heat radiation dummy terminals, the heat radiation dummy terminals can be provided without any additional components. Costs can be reduced and space efficiency can be improved. When there is no unused connection terminal 52, a heat radiation dummy terminal may be separately provided.

  In addition, since the grounding conductor can be configured by using a heat dissipating conductor pattern having a relatively large area, the impedance of the grounding conductor can be advantageously reduced, and noise countermeasure stability can be improved. It can be advantageously secured. Further, since the integrated circuit 28 that is a heat generating component and the board connector 36 are disposed close to each other, the distance between the integrated circuit 28 and the connection terminal 52 that are connected via the solid patterns 18 and 20 that are heat radiation conductor patterns can be shortened. Therefore, the high heat dissipation effect of the connection terminal 52 can be utilized more advantageously.

  As mentioned above, although one Embodiment of this invention has been described, this is an illustration to the last, Comprising: This invention is not limited at all by the specific description in this Embodiment.

  For example, in the present embodiment, the number of dummy terminals for heat dissipation is two, but can be arbitrarily set according to the empty space, the number of unused terminals, required heat dissipation characteristics, etc. There may be three or more.

  In the present embodiment, the solid patterns 18 and 20 constituting the heat-dissipating conductor pattern are provided on both the front surface 14 and the back surface 16 of the printed board 10. However, according to demands for downsizing or cost reduction. It can be set arbitrarily and may be provided only on one of the front surface 14 or the back surface 16 or may be provided on three or more layers of a multilayer wiring printed board having three or more layers.

  Further, in the present embodiment, the connection terminal 52 constituting the heat radiation dummy terminal is made of copper or the like, but gold having a heat radiation property as high as copper or a metal having a heat radiation property higher than copper is used. It may be configured to include. Thereby, since a further higher heat dissipation effect can be obtained, the solid patterns 18 and 20 constituting the heat dissipation conductor pattern can be further reduced. Moreover, since the heat radiation dummy terminal is not connected to the mating connector terminal 64, the strength is not so required. Therefore, silver, which is softer than copper but has high heat dissipation, can be used.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements and the like are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the present invention.

10: Printed circuit board, 18, 20: Solid pattern (conductor pattern for heat dissipation) (grounding conductor), 28: Integrated circuit (heat generating component), 36: Connector for board, 52: Connection terminal, 52a: Connection terminal (for grounding) Terminals), 52b, 52c: connection terminals (heat radiation dummy terminals), 64: mating connector terminals

Claims (4)

In a printed circuit board on which heat generating components are mounted,
A board connector with multiple connection terminals is mounted,
While the heat generating component is connected to the heat dissipating conductor pattern,
The printed circuit board, wherein the plurality of connection terminals of the board connector include a heat radiation dummy terminal that is connected to the heat radiation conductor pattern but is not connected to a counterpart connector terminal.   The plurality of connection terminals of the board connector include a grounding terminal, and the grounding terminal is connected to the heat dissipation conductor pattern, whereby the heat dissipation conductor pattern is used as a grounding conductor. The printed circuit board according to claim 1.   The printed circuit board according to claim 1, wherein the heat radiation dummy terminal includes a metal having a heat dissipation property equal to or higher than that of copper.   The printed circuit board according to any one of claims 1 to 3, wherein the heat generating component and the board connector are disposed adjacent to each other without interposing another mounting component therebetween.

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