JPH1093249A - Heat-radiating structure of printed wiring board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain high density mounting of a printed wiring board, and to provide the heat-radiating structure of a light weight printed wiring board, having superior heat-radiating property. SOLUTION: A printed wiring board is composed of outer layer patterns 111 to be used for soldering of an electric part 3, an internal heat-transmitting layer 13 provided inside a substrate 2 and a via-hole 121 with which an outerlayer and the internal heat-transmitting layer are connected, and the printed wiring board 7 is fixed to an apparatus housing by a metal fitting 14 which penetrates the substrate 2. An electric insulating material 4 is interposingly provided between the outerlayer pattern 111, the metal fixing means 14 and a apparatus housing 5. The heat generated by the electronic part 3 is dissipated through the outerlayer pattern, the via-hole, the internal heat-transmitting layer and the metal fixing means toward the apparatus housing. It is desirable that the internal heat-transmitting layer be connected to be cross-section a through- hole 16, provided on the side face of the substrate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat dissipation structure for a printed wiring board having excellent heat dissipation.

[0002]

2. Description of the Related Art Conventionally, as a printed wiring board, for example,
As shown in FIG. 4, there is an electronic component 92 fixed on an outer layer pattern 971 provided on the surface of a substrate 91.
The electronic component 92 includes a terminal 94 connected to the electronic component 92.
Are connected to the outer layer pattern 930 by soldering.

The electronic component 92 is mounted on the surface of the substrate 91 by inserting a screw 961 into a mounting hole 95 passing through the electronic component 92 and the substrate 91 and fastening the other surface of the substrate 91 with a nut 962. Fixed. The heat generated from the electronic component 92 is transmitted to the outer layer pattern 971 and the comb-shaped heat sink 972 provided on the surface of the substrate 91, and is mainly radiated outward from the tip 973 of the heat sink 972.

[0004]

By the way, in the above-mentioned conventional printed wiring board, it is required that the heat dissipation be improved with an increase in the amount of electricity used by the electronic components 92. In order to obtain high heat dissipation, the heat sink 972 needs to be provided over a wide area. However, the heat sink 97 provided over a large area
2, the area where the outer layer pattern can be formed on the substrate surface is reduced. For this reason, increasing the area of the heat sink impedes high-density wiring and high-density mounting on the substrate surface.

The heat sink 972 is of a comb tooth shape, and its tip protrudes above the substrate 91. Therefore, the thickness of the heat sink is increased by the height of the comb teeth, thereby increasing the overall thickness of the printed wiring board. In addition, since the heat sink 972 is generally made of copper having good heat conductivity, the heat sink 972 is heavy, which hinders the weight reduction of the printed wiring board.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has as its object to provide a light-weight heat-dissipating structure for a printed-wiring board capable of realizing high-density mounting of a printed-wiring board and having excellent heat-dissipating properties. .

[0007]

According to a first aspect of the present invention, an outer layer pattern for soldering an electronic component, an inner heat transfer layer provided inside a substrate, and a space between the outer layer pattern and the inner heat transfer layer are provided. A printed wiring board having a via hole to be connected thereto, and a device housing fixed by a metal fixing tool penetrating the substrate, and an electrical connection between the outer layer pattern and the metal fixing device and the device housing. Insulating material is provided, and heat generated from the electronic component is radiated to the device housing via the outer layer pattern, the via hole, the internal heat transfer layer, and the metal fixture. This is a characteristic heat dissipation structure of a printed wiring board.

The operation and effect of the present invention will be described.
The printed wiring board of the present invention uses heat generated from electronic components to
Transfer to the outer layer pattern and then to the internal heat transfer layer via holes. The internal heat transfer layer is
Conducts heat to the metal fixture that penetrates the substrate. The heat transmitted to the metal fixture is transmitted to the device housing, where it is radiated.

Further, the equipment housing generally has a larger surface area than the printed wiring board. Therefore, the device housing not only functions as a housing, but also functions as a good heat radiating material and efficiently dissipates heat. Therefore,
The heat radiation member such as the heat sink shown in the conventional example is unnecessary. Therefore, a large mounting area can be secured by the area required for the heat radiating member, and high-density mounting of the outer layer pattern, electronic components, and the like is possible. Also, the weight and size of the printed wiring board can be reduced by an amount corresponding to the removal of the heat sink.

Also, between the outer layer pattern and the metal fixture,
An electrical insulating material is interposed between the outer layer pattern and the device housing. Therefore, only heat transfer is performed during these periods, and electrical insulation is ensured. In addition, the internal heat transfer layer not only functions as a heat conduction path, but also, for example,
It can play various roles such as a grounding pattern and a power supply pattern.

Next, it is preferable that the internal heat transfer layer is connected to a cross-sectional through hole provided on a side surface of the substrate. Thus, the heat transmitted to the internal heat transfer layer can be dissipated outward not only from the metal fixture and the device housing, but also from the cross-sectional through holes provided on the side surface of the substrate.

It is preferable that the metal fixture is a screw that is screwed into a screw hole provided in an equipment housing. Thus, the printed wiring board can be easily and reliably fixed to the device housing. In addition, as the electric insulating material, for example, an insulating material having good heat conductivity such as a plum can be used.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A heat radiation structure for a printed wiring board according to an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the printed wiring board 7 of this embodiment includes an outer layer pattern 111 provided on the surface of the substrate 2 for soldering the electronic components 3, an internal heat transfer layer 13 provided inside the substrate 2, Outer layer pattern 111 and inner heat transfer layer 13
And a via hole 121 connecting between the two.
The printed wiring board 7 includes a metal fixture 14 penetrating the substrate 2.
, Is fixed to the device housing 5.

The space between the outer layer pattern 111 and the metal fixture 14 and the space between the outer layer pattern 111 and the equipment housing 5 are:
An electric insulating material 4 is interposed. The electric insulating material 4 is an insulating material having good heat conductivity, such as a mound. The heat generated from the electronic component 3 is radiated to the device housing 5 via the outer layer pattern 111, the via hole 121, the internal heat transfer layer 13, and the metal fixture 14. The metal fixture 14 is a screw, is inserted into a fixing hole 125 penetrating the substrate 2, and is screwed to a nut 51 fixed to the device housing 5.

The internal heat transfer layer 13 is connected to the via holes 121 and 122 as shown in FIG. On the other hand, the internal heat transfer layer 13 is insulated from the fixing hole 125 into which the metal fixture 14 is inserted. Internal heat transfer layer 13
Is a solid pattern formed on almost the entire inside of the substrate 2 as shown in FIG. The internal heat transfer layer 13
It is connected to a cross-sectional through hole 16 provided on the side surface of the substrate 2.

As shown in FIG. 2, the outer layer pattern 111 provided on the surface of the substrate 2 has the electronic component 3 mounted thereon and the cross-section provided on the fixed portion of the metal fixture 14 on the substrate 2 and the side surface of the substrate 2. The through hole 16 is also connected.

As shown in FIG. 1, the printed wiring board 7 is provided with an outer layer pattern 112 on the substrate 2 on the side opposite to the side on which the outer layer pattern 111 is provided.
The terminals 36 provided on the electronic component 3 are connected by soldering to component terminal pads 114 provided at the end of the outer layer pattern 113 for signals.

Next, the operation and effect of this embodiment will be described. As shown in FIG. 1, the printed wiring board 7 of this embodiment transmits heat generated from the electronic component 3 to the outer layer pattern 111,
Then, the internal heat transfer layer 1 is formed by the via holes 121 and 122.
3 The internal heat transfer layer 13 transfers heat inside the substrate 2 to a metal fixture 14 penetrating the substrate 2. The heat transmitted to the metal fixture 14 is transmitted to the device housing 5, where it is radiated.

The device housing 5 generally has a larger surface area than the printed wiring board 7. Therefore, the device housing 5 does not only function as a housing,
It works as a good heat dissipating material and dissipates heat efficiently. Thus, according to the heat dissipation structure of the printed wiring board of this example,
The heat generated from the electronic component 3 can be efficiently radiated.

Therefore, the heat radiating member such as the heat sink shown in the conventional example is unnecessary. Therefore, a large mounting area can be secured by the area required for the heat radiating member, and high-density mounting of the outer layer pattern, electronic components, and the like is possible. Also, the weight and size of the printed wiring board can be reduced by an amount corresponding to the removal of the heat sink.

Further, since the internal heat transfer layer 13 has a solid pattern as shown in FIG. 3, it has a large heat transfer area and excellent heat transfer properties. Further, between the outer layer pattern 111 and the metal fixture 14, and between the outer layer pattern 111 and the device housing 5, the electric insulating material 4 is provided. for that reason,
During these periods, only heat transfer is performed and electrical insulation is ensured. Further, the internal heat transfer layer 13 is connected to a cross-sectional through hole 16 provided on the side surface of the substrate 2. Therefore, the heat transmitted to the internal heat transfer layer 13 can be radiated outward not only from the metal fixture and the device housing but also from the cross-sectional through hole 16.

[0022]

According to the present invention, it is possible to realize a high-density mounting of a printed wiring board, and to provide a light-weight heat-dissipating structure for a printed wiring board which is excellent in heat dissipation.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a printed wiring board cut along a line AA shown in FIG. 2;

FIG. 2 is a plan view of a printed wiring board according to the embodiment.

FIG. 3 is a sectional view of the printed wiring board taken along the line BB shown in FIG. 1;

FIG. 4 is a sectional view of a printed wiring board in a conventional example.

[Explanation of symbols]

 111-113. . . Outer layer pattern, 121, 122. . . Via holes, 125. . . 12. mounting holes, . . Internal heat transfer layer, 131. . . 13. inner layer pattern; . . Metal fixture, 16. . . 1. through-hole cross section, . . Substrate, 3. . . Electronic components, 4. . . 4. electrical insulation; . . Equipment housing, 7. . . Printed wiring board,

Claims (2)

[Claims] 1. A print having an outer layer pattern for soldering an electronic component, an inner heat transfer layer provided inside a substrate, and a via hole connecting between the outer layer pattern and the inner heat transfer layer. A wiring board and a device housing fixed by a metal fixture penetrating the substrate, and an electrical insulating material is interposed between the outer layer pattern and the metal fixture and the device housing. Wherein the heat generated from the electronic component is radiated to the equipment housing via the outer layer pattern, the via hole, the inner heat transfer layer, and the metal fixture. Construction. 2. The internal heat transfer layer according to claim 1,
A heat dissipating structure for a printed wiring board, wherein the heat dissipating structure is connected to a through hole provided on a side surface of a substrate.