JP6978828B2 - Heat dissipation structure of electronic devices and electronic devices - Google Patents

Description

The present invention relates to an electronic device for efficiently dissipating heat in an electronic device provided with a high heat generating body in a narrow region and realizing miniaturization, and a technique for the heat dissipation structure thereof.

In recent years, in order to reduce the size of electronic devices, modularization of electronic components housed in the electronic devices has been progressing. Modularization does not require the process of arranging individual small electronic components on a substrate, and has the advantage of facilitating the manufacture of electronic devices. However, since the heat-generating components are integrated in the module, the amount of heat generated inside becomes large, and at the same time, the path for releasing heat to the outside is limited, and there is a problem that the heat generated inside is not properly processed. Further, since problems of thermal damage such as malfunction and breakage are likely to occur due to the influence of mutual heat generated from a plurality of electronic components in the housing, a method for efficiently dissipating heat in a limited space is required.

Generally, heat dissipation methods for electronic devices include a method of forcibly generating an air flow by installing a fan to release heat, a method of arranging a heat sink in a heat source to promote heat dissipation, and a fan and heat sink. Many heat dissipation methods that combine the above are adopted. For example, Patent Document 1 shows a cooling device in which a heat sink is arranged on a communication LSI. Further, Patent Document 2 discloses a cooler for electronic components that dissipates heat generated by electronic components by using a heat sink and an electric fan.

Japanese Unexamined Patent Publication No. 2015-50262 Japanese Unexamined Patent Publication No. 2002-64171

The above-mentioned Patent Document 1 provides a certain solution regarding both heat dissipation of a communication LSI and miniaturization of a cooling device. However, although the surface temperature of an LSI or the like, which is a heat source, can be lowered, there may be a problem that the temperature of the surface of the housing rises because the heat is discharged into the housing of the electronic device. Further, in Patent Document 2, since an electric fan is used in addition to the heat sink, it does not provide a solution to the miniaturization of the electronic device.

Since the fan can forcibly create an air flow inside the electronic device and cool the inside, it can be installed relatively without being restricted by the installation location and the shape of the heat source like a heat sink, but electronic. Not only did the device become larger, but there were also problems such as noise generation and maintenance. Further, since dust and the like are wound up in the electronic device, there is also a problem that a malfunction occurs due to the dust.

Therefore, in the present invention, in an electronic device such as a media converter, even if a plurality of electronic components serving as heat sources are placed in a housing, the heat source can be cooled in a narrow space by efficiently dissipating heat by natural air cooling. To provide a heat dissipation structure for an electronic device and an electronic device that does not cause heat damage while achieving a compact heat dissipation structure.

In order to solve the above problems, the first aspect of the present invention is a housing having a bottom surface, an upper surface provided with fins as a first heat sink and a hole leading to the inside of the housing, and side surfaces. And, in the first heat source where the upper surface is arranged close to the area where the hole of the first heat sink is not provided in the housing, and in the area where the hole exists in the upper space which is arranged adjacent to the first heat source in the housing. A heat dissipation structure consisting of a housing having a second heat source to be arranged, an electronic device including a bottom surface, a top surface provided with fins as a first heat sink and a hole leading to the inside of the housing, and side surfaces. Therefore, the first heat source is arranged in the housing with the upper surface close to the area where the hole of the first heat sink is not provided, and the second heat source is arranged adjacent to the first heat source in the housing in the upper space. Provided is a heat sink structure of an electronic device configured to be placed in an area where a hole exists.

Further, the second invention has a second heat sink arranged in the housing close to the upper surface of the second heat source so that the upper surface of the second heat sink is separated from the upper surface provided with the hole. Provided are the arranged electronic device according to claim 1 and the heat dissipation structure of the electronic device according to claim 9.

Further, in the third invention, the volume of the housing is 100 cubic centimeters or less, the first heat source is in the range of 1.0 watt to 2.5 watts, and the second heat source is 5.0 watts to 7. Provided is the heat dissipation structure of the electronic device according to claim 1 or 2 and the electronic device according to claim 9 or 10, which is in the range of 0 watts.

The fourth invention is the electronic device according to claim 1 to 3 and the electronic device according to claim 9 to 11, wherein the side surface and / or the bottom surface of the housing is provided with a hole leading to the inside of the housing for natural air cooling. Provides a heat dissipation structure for electronic devices.

The fifth aspect of the invention is described in any one of claims 1 to 4, wherein the upper surface portion of the first heat sink is thicker than the other constituent portions of the housing and has a relatively large heat capacity. The heat dissipation structure of the electronic device of the above and the electronic device according to any one of claims 9 to 12 is provided.

A sixth aspect of the present invention provides the electronic device according to claim 5 and the heat dissipation structure of the electronic device according to claim 13, wherein the thick component portion is provided with a hole in a part thereof.

The electronic device according to any one of claims 1 to 6, wherein the first heat source is an external input / output terminal circuit structure module including a power amplifier, and the second heat source is a communication LSI. And the heat dissipation structure of the electronic device according to any one of claims 9 to 14.

Further, in the eighth invention, a chip component is planted on the back surface side of the printed circuit board on which the second heat source is arranged, and the heat radiation sheet comes into contact with the bottom surface so that the planted chip component is embedded. A heat dissipation structure for an electronic device according to any one of claims 1 to 7 and an electronic device according to any one of claims 9 to 15 is provided.

Due to the electronic device of the present invention and the heat dissipation structure of the electronic device, in an electronic device such as a media converter, even if a plurality of electronic components that serve as a large heat source are installed in the housing, heat is efficiently dissipated by natural air cooling while reducing the size. It is possible to prevent the problem of heat damage such as malfunction and breakage. Furthermore, since it does not use an electric fan, it is clean without raising dust, etc., maintenance is easy, and it is possible to extend the service life and reduce noise.

Overall perspective view showing an example of the electronic device and its heat dissipation structure in Examples 1 and 7. Full perspective exploded view showing an example of the electronic device and its heat dissipation structure in the first embodiment. A plan view and a cross-sectional view showing an example of the electronic device and its heat dissipation structure in the first embodiment. A plan view and a cross-sectional view showing an example of the electronic device and its heat dissipation structure in the first embodiment. A plan view and a cross-sectional view showing an example of the electronic device and its heat dissipation structure in the first embodiment. A plan view and a cross-sectional view showing an example of the electronic device and its heat dissipation structure in the first embodiment. A plan view and a cross-sectional view showing an example of the electronic device and its heat dissipation structure in the first embodiment. Full perspective exploded view showing an example of the electronic device and its heat dissipation structure in the second embodiment. A plan view and a cross-sectional view showing an example of the electronic device and its heat dissipation structure in the second embodiment. Full perspective exploded view showing an example of the electronic device and its heat dissipation structure in Example 4. Overall perspective view and cross-sectional view showing an example of the electronic device and its heat dissipation structure in the fourth embodiment. An overall perspective view of the housing and a cross-sectional view of the electronic device showing an example of the electronic device and its heat dissipation structure in the fourth embodiment. Cross-sectional view showing an example of an electronic device and its heat dissipation structure in Example 4. A plan view and a cross-sectional view showing an example of the housing of the electronic device and its heat dissipation structure according to the fifth embodiment. Overall perspective view showing an example of the electronic device and its heat dissipation structure according to the sixth embodiment. Sectional drawing which shows an example of the electronic device and the heat dissipation structure thereof in Example 6. Sectional drawing which shows an example of the electronic device and the heat dissipation structure thereof in Example 8. Full perspective exploded view showing an example of the electronic device and its heat dissipation structure in Example 8.

0110 Housing 0111, 0121, 1411, 1511 Bottom surface 0112, 0212, 1512 Top surface 0113, 0213, 1513 Side surface 0214, 0314, 1514 Top surface hole 1515 Survey surface hole 1516 Bottom surface hole 0217, 0317 First heat sink on the top surface of the housing Area 0218,0318 Area where the hole on the upper surface of the housing exists 0319 Screw 1
0320 screw 2
0221, 0321, 1521 1st heat source 0222, 0322, 1422, 1522 2nd heat source 0223, 0323, 1523 1st heat sink 0224, 0324, 1524 Fins 1525 2nd heat sink 0330 Plate 0331, 1531 Heat sink 1
1532 Heat dissipation sheet 2
1433, 1533 Heat dissipation sheet 3
0141 External I / O Terminal Circuit Structure Module 0142 Communication LSI
0143, 1543 Printed circuit board 1444 Chip parts 0145, 0245, 0345, 1545 Slot 0246 Slot top hole 0147 Cable insertion slot 0148 Cable insertion slot

Hereinafter, embodiments of each invention will be described. The present invention is not limited to these embodiments, and can be implemented in various forms without departing from the gist thereof. The relationship between the following examples and the claims is as follows. The first embodiment mainly describes claims 1 and 9. 2 is mainly for claims 2 and 10, Example 3 is mainly for claims 3 and 11, Example 4 is mainly for claims 4 and 12, and Example 5 is. Mainly regarding claims 5 and 13, Example 6 mainly regarding claims 6 and 14, Example 7 mainly regarding claims 7 and 15, and Example 8 mainly regarding claims 8. 16 and the like will be described.

<Concept of Example 1>

As the electronic device in the first embodiment, a media converter device will be described as an example, but it can also be applied to other electronic devices. As shown in the conceptual diagram of FIG. 1, the media converter device in this embodiment includes an external input / output terminal circuit structure module (0141) including a power amplifier on a printed circuit board (0143) in a housing and a communication LSI (0142). ) Is provided. The external input / output terminal circuit structure module is housed in the slot (0145). It has an SFP + cable insertion slot (0147) from the front right side of the housing and a UTP or STP cable insertion port (0148) from the front left side of the housing. The housing (0110) shown by the broken line in FIG. 1 is composed of a bottom surface (0111), a top surface (0112), and a side surface (0113). Although the description is simplified in FIG. 1, many electronic components such as integrated circuits and chip components are installed on the upper surface and the lower surface of the printed circuit board in addition to the external input / output terminal circuit structure module and the communication LSI. ..

FIG. 2 is a full-scale perspective exploded view showing an example of the electronic device and its heat dissipation structure in the first embodiment, and is a conceptual diagram showing an example of a case where the components of the electronic device in the present invention are installed on a printed circuit board. A first heat source (0221), which is an external input / output terminal circuit structure module, and a second heat source (0222), which is a communication LSI, are installed adjacent to each other on a printed circuit board above the bottom surface of the housing. In FIG. 2, the first heat source is drawn so as to point to the slot (0245) for accommodating the external input / output terminal circuit structure module, but in reality, the internal external input / output terminal circuit structure module is used. It points to. The upper surface of the housing is provided with fins (0224) as a first heat sink (0223) and holes (0214) leading to the inside of the housing. In FIG. 2, the first heat sink on the upper surface of the housing is shown in a shaded pattern, and the heat sink is composed of a plate portion and fins as a base. Further, in FIG. 2, a region (0217) in which the hole of the first heat sink is not provided and a region (0218) in which the hole (0214) is present are shown by being surrounded by a broken line.

3A to 3C are conceptual diagrams showing an example of the electronic device and its heat dissipation structure according to the first embodiment. 3A (a) is a plan view of the electronic device, and FIG. 3A (b) is a cross-sectional view taken along the line AA'of the electronic device. The direction of movement is indicated by an arrow. The first heat source (0321) is arranged in the housing so that the upper surface thereof is close to the region region (0317) in which the hole of the first heat sink (0323) is not provided. FIG. 3A (b) shows an example in which the external input / output terminal circuit structure module, which is the first heat source, is housed in the slot (0345). It is desirable to use an integrally molded product for the upper surface portion as the first heat sink. For example, as shown in FIG. 3A (a), screws 1 (0319) and screws 2 (0320) are used on the upper surface other than the first heat sink. It is fixed to the portion, and both can form the upper surface of the housing.

The heat generated by the first heat source is naturally dissipated directly from the surface of the fin (0324) of the first heat sink (0323) on the upper surface of the housing to the outside of the housing. In FIG. 3A (b), the plate portion (0330) of the first heat sink is covered with a wavy line, but in general, in a heat sink having such fins, the heat transferred from the heat source is received by the plate portion of the heat sink. , It is configured to cool by discharging from the fin surface with a large surface area.

When the first heat sink is arranged in the housing, a space corresponding to the volume is required in the housing, but in the present invention, the first heat sink in contact with the first heat source is a part of the upper surface of the housing, so that it is large in the housing. Does not require space. Therefore, the height of the housing can be lowered, and as a result, the electronic device can be miniaturized. In this embodiment, a heat dissipation sheet 1 (0331) is arranged between the first heat sink and the first heat source in order to improve heat transfer, and an example is shown in which the first heat sink and the first heat source are brought into close contact with each other. It is preferable to install a heat dissipation sheet as described above.

FIG. 3B is an example in which the thickness of the region where the hole is present on the upper surface of the embodiment of FIG. 3A is set to the wall thickness, and other configurations are the same as those of FIG. 3A. As a part including a portion on the upper surface as the first heat sink and a portion having a hole, for example, a component in which both are integrally molded can be used. FIG. 3C shows an example of the fixing method. The shaded portion of FIG. 3C (a) is a portion that cannot be seen from the upper surface of the integrated component including the first heat sink. 3C (b) is a cross-sectional view taken along the line AA', and FIG. 3C (c) shows a cross-sectional view taken along the line B-B'. As shown, it can be fixed with screw 1 (0319) and screw 2 (0320). However, it is also possible to use a method such as welding or the use of an adhesive as a method of joining the integrally molded part including the first heat sink and the upper surface portion of another housing, and the method is not limited to screwing.

The second heat source (0322) is arranged adjacent to the first heat source in the housing and is arranged in a region (0318) where a hole exists in the upper space. As shown in (b) of FIGS. 3A and 3B, the heat generated by the second heat source is naturally dissipated to the upper surface space of the second heat source, and further, at a position facing the second heat source from the upper surface space of the second heat source. The heat is naturally dissipated to the outside of the housing through the hole at the top of the housing provided. The second heat source is an electronic component having a lower height than the first heat source due to its structure. Therefore, a space can be provided between the second heat source arranged adjacent to the first heat source and the upper part of the housing. Since the warmed air has a low density and therefore has the property of rising, the heat discharged from the second heat source rises inside the housing and further rises to the outside of the housing through the holes provided on the upper surface of the housing. do. The second heat source can be naturally dissipated by this air flow.

<Structure of Example 1>
Again, the configuration of this embodiment will be described with reference to FIG. The "electronic device" of the present invention has a bottom surface (0211), a top surface (0212) provided with fins (0224) as a first heat sink (0223), and a hole (0214) leading to the inside of the housing, and a side surface (0212). 0213), a first heat source (0221) whose upper surface is arranged close to a region (0217) where a hole for a first heat sink is not provided in the housing, and a first heat source in the housing. It is composed of a second heat source (0222) arranged adjacent to the region (0218) in which a hole exists in the upper space.

Further, the "heat dissipation structure of the electronic device" of the present invention will be described with reference to FIG. From a housing having a bottom surface (0211), a top surface (0212) provided with fins (0224) as a first heat sink (0223) and a hole (0214) leading to the inside of the housing, and a side surface (0213). In this heat dissipation structure, the first heat source (0221) is arranged in the housing with the upper surface close to the region (0217) where the hole of the first heat sink is not provided, and the second heat source (0222) is arranged in the housing. Is arranged adjacent to the first heat source and is arranged in a region (0218) where a hole exists in the upper space. Hereinafter, each configuration will be described.

The "housing" has a bottom surface, an upper surface provided with fins as a first heat sink and a hole leading to the inside of the housing, and side surfaces. The housing is a box that serves as the outer shell of an electronic device, and is configured to accommodate a substrate inside. The housing of FIG. 2 is a box having rectangular side surfaces and bottom surfaces, but is not limited thereto. However, a shape that does not fit the purpose of miniaturization is not preferable. As the material forming the housing, SECC (electrogalvanized steel plate) and aluminum, which are resistant to rust, are often used, but other metals and resins may also be used. In this embodiment, SECC and aluminum are used.
A printed circuit board is placed above the "bottom". A printed circuit board is an electronic board for mounting a large number of electronic components, and mounts various electronic circuits composed of these electronic components. The "side surface" is a surface in contact with the upper surface and the bottom surface, and has a role of supporting the upper surface.

The "upper surface" is provided with fins as a first heat sink and is provided with a hole leading to the inside of the housing. The "fins" are provided as a first heat sink. The fins form a first heat sink together with a base plate, and project from the plate toward the upper surface of the housing. The shape of the plate is not particularly limited as long as it is long, and may be elliptical or the like. The heat sink generally receives heat from a heating element at the plate portion and dissipates heat from the fin surface.

It is desirable that the area occupied by the plate of the first heat sink is larger than the area of the upper surface of the first heat source. However, if it is too wide, it will hinder the miniaturization of electronic devices. Therefore, it is preferable that the size is at least the same as or larger than the region on the upper surface of the first heat source. Further, the contact surface between the first heat source and the plate does not have to be a horizontal plane, and may be inclined as long as it is in contact with the first heat source.

In this embodiment, the plate has a thickness of about 2 mm, a width of about 17 mm, a length of about 67 mm, and a fin height of about 3 mm. The upper surface portion as the first heat sink will be described in detail in Example 5, but it is preferable that the upper surface portion is thicker than the other constituent portions of the housing. As shown in FIG. 2, in the present embodiment, the region of the first heat sink is wider behind the upper surface of the first heat source in the longitudinal direction.

In FIGS. 1 to 15, plate-shaped straight fins are shown as fins, and the fins are arranged in parallel with each other in the longitudinal direction of the first heat source. The shape of the first heat sink is not limited to the plate-shaped straight fins, and may be, for example, a plurality of columnar pin fins from the viewpoint of enhancing heat dissipation. When pin fins are used, they can be arranged not only in the longitudinal direction of the first heat source but also in a matrix or a staggered pattern. The fins and plate can be integrally molded from the same material as the plate by extrusion. Further, the fins and plates may be formed by cutting, drawing, or the like, and the processing method is not limited.

Aluminum and aluminum alloys are preferably used as the material constituting the heat sink, but other metal materials having high thermal conductivity such as copper and iron can also be used. Further, it is preferable to perform alumite treatment, painting, etc. in order to improve the heat dissipation effect and corrosion resistance and turn left. In this embodiment, an aluminum heat sink in which a plate and fins are integrally molded and anodized is used as the first heat sink.

The "first heat source" is arranged in the housing with its upper surface close to the area of the first heat sink. Further, the heat dissipation structure of the electronic device of the present invention is configured such that the first heat source is arranged in the housing so that the upper surface thereof is close to the region of the first heat sink. "Arranged in close proximity" means that the area occupied by the first heat source and the area of the first heat sink are close to each other or are in contact with each other to the extent that they affect each other. It is not an exclusion. "Arrangement" means arranging and fixing in a predetermined position.
Explaining with reference to FIG. 2, the first heat source (0221) is an external input / output terminal circuit structure module inserted and arranged in a case such as a slot (0245). The purpose of storing in the slot is to shield the internal circuit board from the influence of electromagnetic waves and the like, and to protect parts vulnerable to vibration from impacts and the like. A space is configured in the front portion of the slot in the longitudinal direction so that an external input / output terminal can be inserted. Further, in this embodiment, 12 substantially circular holes (0246) having a diameter of about 2 mm are provided on the upper surface of the slot.

FIG. 4A is a conceptual diagram showing an example of the electronic device and its heat dissipation structure according to the first embodiment. 4A (a) is a plan view of the electronic device, FIG. 4A (b) is a cross-sectional view taken along the line A-A'of the electronic device, and FIG. 4A (c) is a cross-sectional view taken along the line BB'of the electronic device. be. The arrow in the figure shows an example of the direction in which heat is transferred in the first embodiment. The heat generated by the first heat source is transferred to the heat radiating sheet (0431) in contact with the slot through the upper surface of the slot (0445), and the heat radiated from the substantially circular hole (0446) on the upper surface of the slot. There are two ways of transmitting to the heat dissipation sheet. Then, heat is transferred from the heat dissipation sheet to the plate portion (0430) of the first heat sink, and heat is dissipated from the fin surface to the outside of the housing.

Although FIG. 4A shows an example in which the first heat source is not in contact with the slot, the first heat source may be in contact with the slot. Further, since the heat radiating sheet is elastic, it can be arranged in contact with the first heat source and the slot for accommodating the first heat source so that the heat radiating sheet is embedded in the substantially circular hole on the upper surface of the slot. An insertion port (0447) for an SFP + cable is arranged in front of the first heat source.

As shown in FIG. 4A (b), of the area of the first heat sink on the upper surface, the portion surrounded by the broken line in FIGS. It occupies the area that is not close to the first heat source. Most of the heat generated by the first heat source is transferred to the plate above the first heat source and then released from the upper fin surface to the outside of the housing. Then, as shown in FIG. 4A (b), a part of the heat transferred to the plate is also transmitted to the rear in the longitudinal direction of the plate and is discharged to the outside of the housing from the fins on the upper portion thereof, so that the heat can be dissipated more efficiently. Further, although not shown in detail in FIG. 4A (b), electronic components that can be heat sources are arranged in the housing in addition to the first heat source and the second heat source, although the calorific value is not so high. For example, as shown in FIG. 4A (b), the heat generated by the electronic component 1 (0461) and the electronic component 2 (0462) can be transferred to the first heat sink and released to the outside of the housing.

It is preferable that the first heat sink and the first heat source or the case (for example, a slot) that houses the first heat sink and the first heat source and the first heat source are brought into close contact with each other by a heat radiating sheet or the like to improve heat transfer. There are various ways to improve the efficiency of heat transfer between the first heat sink and the first heat source or the case (for example, a slot) containing the first heat sink and the first heat source and the first heat source. There is a method of indirectly reducing the heat transfer resistance of both by the adhesive force of the heat dissipation sheet itself, or a method of using grease, double-sided adhesive tape and adhesive on the pressure-bonding surface of the heat dissipation sheet, the first heat sink and the first heat source. be. When using a grease having a high heat transfer efficiency, a double-sided adhesive tape having a high heat transfer efficiency, and an adhesive having a high heat transfer efficiency, it is necessary to pay attention to their heat conductivity. That is, the material is selected so that either transfer or heat conduction does not become another bottleneck. There is also a method of putting a foot on the printed circuit board from the first heat sink and fixing it with a screw. In this embodiment, as shown in FIGS. 3A, 3B (0331) and 4 (0431), an adhesive heat dissipation sheet made of an acrylic material is arranged between the first heat sink and the first heat source to improve heat transfer. I'm letting you.

The heat dissipation sheet is installed by crimping between the first heat source and the first heat sink that require heat dissipation. There are several reasons why the first heat sink is not placed directly on the first heat source and the case (eg, slot) that houses the first heat source. First, even if hard objects are brought into close contact with each other, they do not come into close contact with each other completely, and it is difficult to efficiently transfer heat between the first heat source, which is an electronic component, and the first heat sink. However, if a soft material is sandwiched between the two, the two can be indirectly brought into close contact with each other to enhance heat transfer. Secondly, it is necessary to avoid the situation where the impact received by the first heat sink (upper surface of the housing) is transmitted to the electronic components and damages the electronic components, but if a soft material is sandwiched between the two, the first heat sink receives it. The impact is not directly transmitted to the electronic component, and the electronic component can be protected from the impact.

The material of the heat radiating sheet is preferably soft, adhesive, and has high thermal conductivity. Generally, acrylic and silicon materials are often used. In addition, graphite or the like can be used. In this embodiment, an example is shown in which a heat dissipation sheet having a width of 14 mm and a depth of 41 mm and a thickness of 1.5 mm made of an acrylic material is used.

To explain again with reference to FIG. 2, the "second heat source" (0222) is arranged adjacent to the first heat source (0221) in the housing and is arranged in the region (0218) where the hole (0214) exists in the upper space. do. In FIG. 2, the area where the hole exists is shown by being surrounded by a broken line.
Further, the heat dissipation structure of the electronic device of the present invention is configured such that the second heat source is arranged adjacent to the first heat source in the housing and is arranged in the region where the hole exists in the upper space. The present invention is characterized in that the first heat source and the second heat source are arranged adjacent to each other.
"Adjacently arranged" means that the area occupied by the first heat source and the area occupied by the second heat source are arranged close to each other, but other electronic components are arranged between the two areas. It does not exclude, but includes the placement of other electronic components between the two regions. Further, in the present invention, specifically, it is "adjacent" that they are arranged at positions where they are mutually affected by heat, that is, they are arranged in a space inside the housing within a distance of 10% or less of the width of the housing. And are arranged. "

FIG. 4B is a conceptual diagram showing an example of the electronic device and its heat dissipation structure according to the first embodiment. FIG. 4B (b) is a plan view of the electronic device. 4A (a) is a cross-sectional view taken along the line AA'of the electronic device, and FIG. 4A (c) is a cross-sectional view taken along the line BB'of the electronic device. The arrow in the figure shows an example of the direction in which heat is transferred in the first embodiment. The heat source of the second heat source (0422) is, for example, the second heat source is an electronic component in which a communication LSI is housed in a case, and due to its characteristics, the heat generation amount in the central portion is higher than that in the end portion. The purpose of putting it in the case is the same as the reason why the external input / output terminal circuit structure module of the first heat source is put in the slot. Further, an insertion port (0448) for a UTP or STP cable is arranged adjacent to the second heat source.

The "hole" (0414) leads into the housing. The hole is an opening formed in the housing. Since the second heat source is arranged in the region where the hole exists in the upper space, the heat discharged by the second heat source is discharged from the hole existing in the upper space of the second heat source. As shown in FIGS. 4A and 4B, the area of the hole arranged on the upper surface of the housing facing the second heat source preferably overlaps the area occupied by the second heat source in the vertical direction, and the second heat source is preferably formed. It is desirable that it is wider than the area occupied by. However, it should be noted that if it is too wide, it cannot be miniaturized. The size of the hole is preferably such that the air flow is not obstructed. However, if it is too large, the strength of the housing will be lowered, and dust and other debris will easily enter, which is not preferable. Therefore, the size of the hole in the upper part of the housing is preferably 1 to 3 mm in width and 5 mm to 15 mm in length. It is preferable that the distance between the holes is about the same as or twice the width of the holes. The shape of the hole is preferably a substantially rectangular shape or an elliptical shape, but the shape is not limited to a substantially square shape or a substantially circular shape.

In this embodiment, as shown in FIG. 4B (a), substantially rectangular holes having a width of 2 mm and a length of 10 mm are formed at positions on the upper surface of the housing facing the second heat source at intervals of 2 mm in the lateral direction. Three rows are arranged at intervals of 2 mm in the longitudinal direction. Of the regions with holes on the upper surface of the housing, the region in the front in the longitudinal direction (0451) almost coincides with the region occupied by the second heat source in the vertical direction, so that most of the heat generated by the second heat source is this. Emitted from the area. On the other hand, the electronic components arranged rearward in the longitudinal direction can also serve as a heat source, although the number of electronic components is smaller than that of the first heat source and the second heat source. The region (0452) rearward in the longitudinal direction also contributes to heat dissipation of a part of the second heat source, but it also contributes to heat dissipation of the electronic component 3 (0463) and the electronic component 4 (0464) arranged in the rearward direction in the longitudinal direction. It is useful.

<Effect of Example 1>
According to the first embodiment, as shown in FIGS. 4A and 4B, first, the heat generated in the first heat source (0421) is the upper surface of the housing provided with fins (0424) as the first heat sink. The heat is naturally dissipated directly to the outside of the housing through the fins. Second, the heat generated by the second heat source rises to the upper part of the second heat source (0422) and is discharged to the outside through a hole (0414) on the upper surface of the housing provided at a position facing the second heat source. .. Here, in the space where heat is released from each heat source, the first heat source is outside the housing, the second heat source is inside the housing, and the space where heat is released is different. The fins of the first heat sink are in contact with the air outside the housing, and most of the heat generated by the first heat source is transmitted to the plate portion of the first heat sink via the heat dissipation sheet 1 (0431) and further discharged from the fin surface. The first heat source emits almost no heat to the space inside the housing.

Since the heat generated by the second heat source is released by the updraft generated by the temperature difference of the air generated in the upper part of the second heat source, it is easily affected by a slight air flow. However, there is almost no heat dissipation from the first heat source to the inside of the housing, and the structure is such that airflow due to other heat sources is unlikely to occur. By adopting such a heat dissipation structure, it is possible to dissipate the heat generated by the first heat source and the second heat source from the narrow housing to the outside.

The electronic device of Example 1 and the heat dissipation structure of the electronic device make it possible to dissipate heat generated by the first heat source and the second heat source in a narrow space without using a device such as a cooling fan. Heat dissipation can be realized and the size of the electronic device can be reduced.

<Concept of Example 2>
FIG. 5 is a full perspective exploded view showing an example of the electronic device and its heat dissipation structure according to the second embodiment of the present invention, and is a conceptual diagram showing an example when the components of the electronic device according to the second embodiment are installed on the printed circuit board. be. The electronic device of the second embodiment and the heat dissipation structure of the electronic device are different from the first embodiment in that the electronic device and the electronic device of the first embodiment are used, and a second heat sink (0525) and a heat dissipation sheet 2 (0532) are provided. ing. That is, the second embodiment is characterized in that the second heat sink arranged close to the upper surface of the second heat source is arranged so as to be separated from the upper surface of the housing provided with the hole.

For example, it is conceivable to dissipate the heat generated by the second heat source by using a heat sink provided on the upper surface of the housing as in the case of the first heat source. However, since the second heat source is a component having a low height due to its nature, some medium is required to transfer the heat to the heat sink on the upper surface of the housing. It is possible to use a metal plate such as a copper plate with high thermal conductivity or a heat dissipation sheet as a medium, but those media require a certain height inside the housing, which makes the weight of the electronic device heavy and costs. There can also be a problem of rising. Therefore, in this embodiment, the second heat sink is arranged close to the second heat source, the heat generated by the second heat source is naturally dissipated to the upper surface of the second heat source via the second heat source, and further, the upper surface of the housing is further provided. It was configured to be discharged from the hole of. The present invention is characterized in that two heat sinks are arranged in different spaces and two heat dissipation paths are provided. Hereinafter, it will be described with reference to FIG.

FIG. 6A is a conceptual diagram showing an example of the electronic device and its heat dissipation structure according to the first embodiment. 6A (b) is a plan view of the electronic device, FIG. 6A (a) is a cross-sectional view taken along the line A-A'of the electronic device, and FIG. 6A (c) is a cross-sectional view taken along the line BB'of the electronic device. be. The arrow in the figure shows an example of the direction in which heat is transferred in the embodiment. Since the second heat sink (0625) is provided in the second embodiment, the heat dissipation path of the heat generated in the second heat source is different from that of the first embodiment. The heat generated by the second heat source is released from the fin surface to the upper space of the second heat source via the heat dissipation sheet 2 (0632) and the plate of the second heat sink adjacent to the second heat source, and further second. Natural heat is radiated to the outside of the housing through a hole (0614) at the top of the housing provided at a position facing the heat source.

In this embodiment, as shown in FIG. 6B (a), substantially rectangular holes having a width of 2 mm and a length of 10 mm are formed at positions on the upper surface of the housing facing the second heat source and the second heat sink, at intervals of 2 mm in the lateral direction. 5 rows are arranged, and 3 rows are arranged with an interval of 2 mm in the longitudinal direction. Of the area with holes on the upper surface of the housing, the area in front of the longitudinal direction (0651) almost coincides with the area occupied by the second heat source and the second heat sink in the vertical direction, so that the heat generated by the second heat source is generated. Most is emitted from this area. The region (0652) rearward in the longitudinal direction has the same configuration as that of the first embodiment and is omitted.

<Structure of Example 2>
In the electronic device of the second embodiment and the heat dissipation structure of the electronic device, the "second heat sink" is arranged close to the upper surface of the second heat source in the housing, and the second heat sink has a hole in the upper surface of the second heat sink. Is arranged so as to be separated from the upper surface of the housing provided with.

In the second heat sink arranged close to the second heat source, heat is transferred from the second heat source to the plate of the second heat sink and further discharged from the fin surface. At the second heat sink, natural convection of air occurs. Natural convection is a flow that occurs only due to the buoyancy caused by the temperature difference of the fluid, in the absence of factors such as a fan that cause the flow.

In this embodiment, since the second heat sink and the housing are arranged so as to be separated from each other, natural convection generated by the second heat sink causes natural heat dissipation from the upper surface of the housing provided with a hole on the upper surface of the second heat sink. Will be done. For example, the distance between the tip of the fin of the second heat sink and the housing in this embodiment is about 6 mm. The state where the second heat sink and the housing are in contact with each other is not preferable because it hinders the generation of natural convection. In addition, heat is transferred from the fins to the first heat sink on the upper surface of the housing at the contact portion, and the total amount of heat that must be dissipated by the first heat sink becomes excessive, so that the heat generated by the first heat source and the second heat source is sufficiently generated. It is not preferable because it cannot be processed.

In the second embodiment, two heat sinks are configured, and the second heat sink is arranged inside the housing, whereas the fins of the first heat sink are in contact with the air outside the housing, and thus are shown in FIG. As described above, the spaces where natural convection occurs are different, and the respective airflows are not affected by each other. In the case of natural air cooling, a slight air flow affects convection and makes cooling difficult, but the second heat sink dissipates heat from the fin surface inside the housing, and the fins of the first heat sink dissipate heat outside the housing. The heat sink structure of the electronic device makes it possible to process the heat generated by the first heat source and the second heat source in a narrow space.

Since the configuration of the second heat sink is the same as that of the first heat sink of the first embodiment, the description thereof will be omitted. However, if the fin pitch is too narrow, natural convection is unlikely to occur and heat is trapped. Therefore, it is preferable that the fin pitch is wide enough to easily cause heat transfer. In this embodiment, a 6 × 6 pin fin is used as the second heat sink, and the plate has a width and depth of about 21 mm, a thickness of about 1.5 mm, and a fin height of about 3.5 mm, and is made of aluminum. I am using the one that has been anodized.

It is preferable that the second heat sink and the second heat source are brought into close contact with each other by a heat radiating sheet or the like as in the case of the first heat sink and the first heat source of the first embodiment to improve heat transfer. In this embodiment, an example is shown in which a heat dissipation sheet having a width of 21 mm and a depth of 21 mm and a thickness of 1 mm made of an acrylic material is used. Other configurations including the heat radiating sheet are the same as those in the first embodiment and are omitted.

<Effect of Example 2>
The second heat sink is arranged in the housing close to the upper surface of the second heat source, and the upper surface of the second heat sink is arranged so as to be separated from the upper surface of the housing provided with the hole, as shown in FIG. As described above, the heat generated by the second heat source is transferred to the plate of the second heat sink adjacent to the second heat source, the heat of the plate is released from the fin surface to the upper space of the second heat source, and further, the position facing the second heat source. The heat is naturally dissipated to the outside of the housing through the hole at the top of the housing provided in. The arrangement of the second heat sink promotes heat transfer of the heat generated by the second heat source to the upper part of the second heat source, and as a result, heat dissipation to the outside of the housing is promoted.

<Concept of Example 3>
The heat dissipation structure of the electronic device and the electronic device of the third embodiment is based on the heat dissipation structure of the electronic device and the electronic device of the first embodiment or the second embodiment, the volume of the housing is 100 cubic centimeters or less, and the first heat source. Is in the range of 1.0 watts to 2.5 watts and the second heat source is in the range of 5.0 watts to 7.0 watts.

<Structure of Example 3>
In the electronic device of Example 3 and the heat dissipation structure of the electronic device, the volume of the housing is 100 cubic centimeters or less, the first heat source is in the range of 1.0 to 2.5 watts, and the second heat source is 5. It is characterized by a range of 0.0 watts to 7.0 watts. The volume is preferably 100 cubic centimeters or less. More preferably, it is 75 cubic centimeters or less. The size of the housing of Example 3 is, for example, 50 mm in width, 74 mm in length, 20 mm in height, and the volume is 74 cubic centimeters.

The maximum power consumption of the first heat source is 2.5 W, and the maximum power consumption of the second heat source is 7.0 watts. With such a configuration, it is possible to implement the electronic device of the first embodiment and the second embodiment and the heat dissipation structure of the electronic device.

<Effect of Example 3>
Even if the housing is small, if the heat source is small enough, no special heat dissipation structure is required. On the other hand, even if the heat source is large to some extent, if the housing is made large and the heat sources are sufficiently separated, heat damage is less likely to occur. According to the electronic device of the first embodiment or the second embodiment and the third embodiment based on the heat dissipation structure of the electronic device, the maximum power consumption of the first heat source is 2.5 W, and the maximum power consumption of the second heat source is 7. Even if there is a heat source as large as 0 watts, it is possible to construct an electronic device having a small size of 74 cubic centimeters and a heat dissipation structure of the electronic device without causing thermal damage.

<Concept of Example 4>
FIG. 7 is a conceptual diagram showing a full-scale perspective exploded view showing an example of the electronic device and its heat dissipation structure in the fourth embodiment. The heat dissipation structure of the electronic device and the electronic device of the fourth embodiment is based on the heat dissipation structure of the electronic device and the electronic device of the first to third embodiments, and is a casing for natural air cooling on the side surface and / or the bottom surface of the housing. It is characterized by having a hole leading to the inside of the body. As shown in FIG. 6, a hole (0715) on the side surface and a hole (0716) on the bottom surface of the housing are provided for natural air cooling.

FIG. 8 is a conceptual diagram of an overall perspective view (a) and a cross-sectional view (b) showing an example of the electronic device and its heat dissipation structure in the fourth embodiment. The directions in which the heat generated by the first heat source and the second heat source in Example 4 are transmitted are indicated by arrows. As shown in FIG. 8, relatively low temperature air flows in from the hole (0815) on the side surface of the housing, and the air warmed by the heat source flows out from the hole (0814) provided on the upper surface of the housing. Since the flow of being discharged occurs, it is possible to more efficiently dissipate the natural heat of the electronic device.
To.

FIG. 9 is a conceptual diagram of an overall perspective view of the housing and a cross-sectional view of the electronic device showing an example of the electronic device and its heat dissipation structure in the fourth embodiment. The direction of heat transfer in Example 4 is indicated by an arrow. FIG. 9A shows an example of the arrangement of the holes (0916) on the bottom surface of the housing. FIG. 9 (b) is a cross-sectional view of a portion having a hole in the bottom surface, and as shown in FIGS. 9 (a) and 9 (b), air having a relatively low temperature on the back surface side of the printed circuit board through the hole in the bottom surface. Inflows and cools the back side of the printed circuit board. Further, the air flowing in from the hole on the bottom surface rises through the gap between the printed circuit board and the side surface of the housing, and is discharged to the outside of the housing through the hole on the top surface of the housing, which naturally dissipates heat from the electronic device. It can be done more efficiently.

FIG. 10 is a conceptual diagram of a cross-sectional view showing an example of the electronic device and its heat dissipation structure in the fourth embodiment. The direction in which heat is transferred when holes are provided in the measuring surface and the bottom surface in Example 4 are indicated by arrows. By providing the holes on the side surface (1015) and the holes on the bottom surface (1016), as shown in FIG. 10, air flows in from the holes on the bottom surface and rises through the gap between the printed circuit board and the side surface of the housing. It merges with the flow of air flowing in from the holes on the side surface, and a good flow is generated in which the air flows out from the holes on the upper surface of the housing to the outside of the housing, which makes it possible to perform more efficient natural heat dissipation.

<Structure of Example 4>
The electronic device of the fourth embodiment and the heat dissipation structure of the electronic device are provided with holes on the side surface and / or the bottom surface of the housing, which lead to the inside of the housing for natural air cooling. "Natural air cooling" refers to cooling in a windless state where wind is not forcibly received from others, and cooling using forced wind using a fan or the like is called forced air cooling.

Since the side surface has a function of maintaining the weight of the upper surface and the strength to withstand the impact from the upper surface to some extent, it is not preferable that the shape is too large or the area occupied by the hole is too wide. Since it is preferable to generate an air flow as shown in FIGS. 8 and 10, the holes on the side surfaces are preferably vertically long substantially rectangular or oblong, and the width is about 0.5 to 2 mm and the length is about 0.5 to 2 mm. Is preferably about 10 to 15 mm. Further, in order to prevent foreign matter such as dust from entering from the outside, it is preferably 1 mm or less. The distance between the holes is preferably about 2 to 5 times the width from the viewpoint of maintaining strength. Further, in order to promote heat dissipation, it is desirable to provide the heat source in a position close to the first heat source and the second heat source.

Since the bottom surface is not loaded with the weight of the top surface and dust is difficult to enter, the bottom surface can be provided without being restricted by the shape, size, number, etc. of the holes as compared with the side surface. However, since it is indispensable to maintain the strength of the housing and the whole, it is preferable that the width is about 1 to 3 mm and the length is about 8 to 15 mm in the case of a vertically long substantially rectangular or substantially elliptical shape.

<Effect of Example 4>
By providing holes leading to the inside of the housing for natural air cooling on the side surface and / or the bottom surface of the housing, the heat generated by the first heat source and the second heat source is transferred from the upper surface of the housing shown in Examples 1 to 3. In addition to the heat dissipation of, relatively low temperature air flows in from the holes on the bottom and the holes on the bottom, and a good air flow occurs that flows out from the holes on the top of the housing to the outside of the housing, and heat is dissipated by natural air cooling. It is promoted and the heat dissipation effect is further enhanced.

<Concept of Example 5>
The heat dissipation structure of the electronic device and the electronic device of the fifth embodiment is based on the heat dissipation structure of the electronic device and the electronic device of the first to fourth embodiments, and the upper surface portion as the first heat sink is from the other constituent parts of the housing. It is also characterized by its thick wall and relatively large heat capacity.

<Structure of Example 5>
FIG. 11 is a conceptual diagram showing an example of the housing of the electronic device and its heat dissipation structure according to the fifth embodiment. 11 (a) is a plan view of the electronic device, FIG. 11 (b) is a cross-sectional view taken along the line AA'of the electronic device, and FIG. 11 (c) shows a cross-sectional view taken along the line BB'of the electronic device. Is. As shown in FIGS. 13 and 13, in the electronic device and the heat dissipation structure of the electronic device according to the present embodiment, the upper surface portion as the first heat sink (1123) is the other constituent portion of the housing (FIG. 11 (b) and FIG. It is characterized by having a thicker wall and a relatively larger heat capacity than the shaded portion in (c).

In FIG. 11, the wall thickness of the upper surface portion of the first heat sink is, for example, about 5 mm, and the other constituent portions of the housing are about 1 mm. The first heat sink is composed of a plate and fins, and the wall thickness of the plate portion is about 2 mm. Comparing the plate portion excluding the fin portion with the other constituent parts of the housing, the wall thickness is doubled, so that the heat capacity is doubled if the same material is used. The upper surface of the first heat sink is thicker than the other components of the housing and has a relatively large heat capacity, which allows the plate to receive a large amount of heat from the first heat source. The heat received by the portion from the first heat source is released from the fins to the outside of the housing, so that heat dissipation can be promoted.

<Effect of Example 5>
The upper surface portion as the first heat sink is thicker than the other constituent portions of the housing and has a relatively large heat capacity, so that efficient heat dissipation can be performed as described above. Further, since the heat capacity of the upper surface portion of the housing is relatively larger than that of the other constituent parts of the housing, the upper surface portion of the housing can hold a large amount of heat, so that heat radiation from the upper surface becomes the mainstream. , It is possible to prevent heat from being trapped inside the housing, and it is possible to reduce the influence of heat on the electronic components inside the housing. Therefore, it is possible to provide an electronic device having a small size and not causing thermal damage, and a heat dissipation structure of the electronic device.

<Concept of Example 6>
The heat dissipation structure of the electronic device and the electronic device of the sixth embodiment is based on the heat dissipation structure of the electronic device and the electronic device of the fifth embodiment, and the thick component is provided with fins as a first heat sink as a whole. It is characterized in that a hole is provided in the portion.

<Structure of Example 6>
FIG. 12 is a conceptual diagram of an overall perspective view showing an example of the electronic device and its heat dissipation structure in the sixth embodiment. As shown in FIG. 12, in the electronic device and the heat dissipation structure of the electronic device according to the present embodiment, a hole (1214) is provided in a part of the upper surface portion as the first heat sink, which is thicker than the other constituent portions. There is. That is, the thick component is provided with fins (1224) as the first heat sink as a whole, and a hole is provided in a part thereof.

FIG. 13 is a conceptual diagram of a cross-sectional view showing an example of the electronic device and its heat dissipation structure in the sixth embodiment, and FIG. 13 (a) is a cross-sectional view of a portion provided with a hole, FIG. 13 (b). Is a cross-sectional view of a portion without holes. The direction in which heat is transferred in Example 6 is indicated by an arrow. As shown in FIG. 13A, most of the heat generated by the first heat source is dissipated from the fin surface of the first heat sink located on the upper surface of the first heat source. Further, the heat generated by the second heat source is naturally dissipated mainly from the hole (1314) provided in a part of the first heat sink. On the other hand, as shown in FIG. 13B, a part of the heat generated by the second heat source is transmitted to the upper surface portion at a position facing the second heat source and not provided with a hole. , Can be dissipated from the fin surface of the first heat sink.

In the part where the hole of the first heat sink is not provided, the following heat dissipation is also assumed. That is, a part of the heat generated in the first heat source is transmitted in the lateral direction above the second heat source through the plate of the first heat sink, and can be further dissipated from the fins. Further, a part of the heat generated by the second heat source can be transferred to the plate of the first heat sink and further dissipated from the fins.

<Effect of Example 6>
The heat dissipation structure of the electronic device and the electronic device of the sixth embodiment is based on the heat dissipation structure of the electronic device and the electronic device of the fifth embodiment, and the thick component is provided with fins as the first heat sink as a whole. , Heat dissipation from the fin surface is added, and efficient heat dissipation can be performed.

<Concept of Example 7>
The electronic device of Example 7 and the heat dissipation structure of the electronic device are based on the heat dissipation structure of the electronic devices and electronic devices of Examples 1 to 6, and the first heat source is an external input / output terminal circuit structure module including a power amplifier. The second heat source is a communication LSI.

<Structure of Example 7>
Example 7 will be described with reference to FIG. 1 again. As shown in FIG. 1, in the electronic device and the heat dissipation structure of the electronic device according to this embodiment, the first heat source is an external input / output terminal circuit structure module (0141) including a power amplifier, and the second heat source is for communication. It is LSI (0142).

The "external input / output terminal circuit structure module" is a module for configuring an input / output terminal for receiving information sent from the outside or sending information to the outside, and includes a circuit. It is a structure. A "communication LSI" is an integrated circuit for communication in which a large number of electronic components (elements) such as transistors, diodes, resistors, and capacitors are incorporated in one semiconductor chip, and is configured as a box-shaped component.

In an electronic device, a large number of electronic components are generally arranged on a substrate, but if the housing is sufficiently large even if each electronic component emits heat, a special heat dissipation structure is not required. .. However, increasing the size of the housing contradicts the miniaturization generally required for electronic devices, and is difficult to be accepted in the electronic device market. The configuration in which electronic components are box-shaped or modularized and stored in a case such as a slot can reduce the size of the entire product rather than arranging individual components on a substrate. Further, in the manufacturing process, there is an advantage that the manufacturing becomes easy.

However, in the case of boxing and modularization of electronic components, electronic components are integrated in a narrow area and the amount of heat is concentrated inside, so it is necessary to cool a large amount of heat concentrated in a certain part. There are challenges. On the other hand, when cooling individual non-modular electronic components, the structure of the electronic device becomes complicated because it is necessary to construct a heat dissipation structure corresponding to each electronic component having a different size, shape, and amount of heat generated. The problem arises. In that respect, the present invention efficiently dissipates heat by constructing a heat radiating structure that is integrated by boxing or modularization, and enables miniaturization of the entire electronic device.

<Effect of Example 7>
The first heat source according to this embodiment is an external input / output terminal circuit structure module including a power amplifier, and the second heat source is an electronic device for communication LSI. The heat dissipation structure of the electronic device is the electrons of Examples 1 to 6. By using the heat dissipation structure of the device and the electronic device as the basis, it is possible to configure the heat dissipation structure of the electronic device and the electronic device which are small in size and do not cause heat damage.

<Concept of Example 8>
The electronic device of Example 8 and the heat dissipation structure of the electronic device are based on the heat dissipation structure of the electronic devices and electronic devices of Examples 1 to 7, and chip parts are planted on the back surface side of the printed circuit board on which the second heat source is arranged. It is installed, and is characterized in that the heat dissipation sheet is arranged in contact with the bottom surface so that the planted chip parts are embedded.

<Structure of Example 8>
FIG. 14 is a conceptual diagram of a cross-sectional view showing an example of the electronic device and its heat dissipation structure in the eighth embodiment. The direction in which heat is transferred in Example 8 is indicated by an arrow. FIG. 14 (b) shows an enlarged part of FIG. 14 (a) including a chip component planted on the back surface side of the printed circuit board. As shown in FIG. 14, a chip component (1444) is planted on the back surface side of the printed circuit board (1443) on which the second heat source (1422) is arranged so that the planted chip component is embedded. The heat radiating sheet 3 (1433) is arranged in contact with the bottom surface (1411) to improve heat transfer. Since the configuration of the heat dissipation sheet is the same as that of the first embodiment, it will be omitted. Chip parts are planted on the back surface side of the printed circuit board on which the second heat source is arranged, and the chip parts can also be a heat source. Further, it is necessary to release the heat transferred from the second heat source via the printed circuit board to the outside of the housing. By arranging the heat dissipation sheet so that the chip component planted on the back surface of the printed circuit board is embedded between the back surface and the bottom surface of the printed circuit board on which the second heat source is arranged, the printed circuit board is connected to the chip component and the second heat source. The heat transferred through the heat dissipation sheet can be transferred to the bottom surface using the heat dissipation sheet as a medium.

When the heat radiating sheet is arranged, the heat generated by the chip parts is promptly transferred to the bottom surface of the housing in contact with the heat radiating sheet. Although the heat dissipation path of the heat transferred to the bottom surface is shown by a broken line arrow in FIG. 14A, the heat is dissipated from the surface of the housing while being conducted inside the housing. A part of it is transmitted from the housing to the first heat sink and radiated from the fin surface.

On the other hand, when the heat dissipation sheet is not arranged, the heat generated by the chip component is discharged in two ways. One is that the heat transferred to the bottom surface of the housing due to radiation or slight natural convection occurring in the narrow space on the back surface side of the printed circuit board is conducted inside the housing and released from the surface of the housing. A part of it can also be dissipated from the first heat sink on the upper surface of the housing. The other is a path that is released with the flow of air rising from the gap between the side surface of the housing and the printed circuit board to the upper part. Since both of these paths use air with low thermal conductivity as a medium, the speed of heat transfer and conduction is slower than when a heat dissipation sheet is arranged, and heat tends to stay in the lower part of the printed circuit board. By arranging the heat dissipation sheet as shown in this embodiment, the heat retention on the back surface side of the printed circuit board is eliminated.

Since the configuration of the heat radiating sheet is the same as that of the first embodiment, the heat radiating sheet is omitted. However, in this embodiment, an example is shown in which a heat radiating sheet having a width of 13 mm and a depth of 17 mm and a thickness of 2 mm made of an acrylic material is used. Since the heat generated in the central portion of the second heat source is concentrated, the heat dissipation sheet and the back surface side of the printed circuit board are in contact with each other at a position vertically below the central portion of the second heat source via the printed circuit board.

FIG. 15 is a full perspective exploded view showing an example of the electronic device and its heat dissipation structure in the eighth embodiment, and is a conceptual diagram showing an example of the configuration in the present invention. The housing has a bottom surface (1511), an upper surface (1512), and a side surface (1513). The upper surface of the housing is provided with fins (1524) as a first heat sink (1523). Although not shown in the figure, the upper surface portion as the first heat sink is thicker than the other constituent portions of the housing, and a hole (1514) is provided in a part thereof.

A first heat source (1521) and a second heat source (1522) are installed adjacent to each other on the surface side of the printed circuit board above the bottom surface of the housing. The first heat source is arranged in the housing close to the area where the hole of the first heat sink is not provided. It is preferable that the heat dissipation sheet 1 (1531) is provided between the first heat sink and the first heat source or between the first heat sink and the case (for example, a slot) for accommodating the first heat source and the first heat source. In FIG. 15, the first heat source is drawn so as to point to the slot (1545) for accommodating the external input / output terminal circuit structure module, but in reality, the internal external input / output terminal circuit structure module is used. It points to.

The second heat source has a second heat sink (1525) that is located in the area where the hole exists in the upper space, but is located close to the upper surface of the second heat source. The second heat sink is arranged so as to be separated from the upper surface where the hole is provided. It is preferable to provide a heat dissipation sheet 2 (1532) between the second heat source and the second heat sink. Although the back side of the printed circuit board on which the second heat source is arranged is not shown, chip parts are planted. The heat radiating sheet 3 (1533) is arranged in contact with the bottom surface so as to be in contact with the planted chip component so as to be embedded.

<Effect of Example 8>
Based on the electronic device of Examples 1 to 7 and the heat dissipation structure of the electronic device, heat is dissipated so that the chip component is embedded in the chip component planted on the back surface side of the printed circuit board on which the second heat source is arranged. By arranging the sheet in contact with the bottom surface, heat dissipation from the chip parts can be efficiently discharged, so that it is possible to construct an electronic device and an electronic device heat dissipation structure that are small in size and do not cause thermal damage. .. In addition, by sandwiching a heat dissipation sheet, which is a soft material, between the printed circuit board and the bottom surface, the impact received by the housing is not directly transmitted to the electronic components, and there is also the effect that the electronic components can be protected from the impact. ..

Claims (14)

A housing having a bottom surface, a top surface provided with fins as a first heat sink and a hole leading to the inside of the housing, and side surfaces.
A first heat source whose upper surface is placed close to the area where the hole of the first heat sink is not provided in the housing,
A second heat source arranged adjacent to the first heat source in the housing and arranged in the area where the hole exists in the upper space,
Consists of
The second heat source is an electronic component having a height lower than that of the first heat source, and is an electronic device provided with a space between the second heat source and the upper part of the housing.
The upper surface portion as the first heat sink is an electronic device that is thicker and has a relatively larger heat capacity than the other constituent portions of the housing. The first aspect of the present invention has a second heat sink arranged in the housing close to the upper surface of the second heat source, and the upper surface of the second heat sink is arranged so as to be separated from the upper surface provided with the hole. The electronic device described. The volume of the housing is 100 cubic centimeters or less, the calorific value of the first heat source is in the range of 1.0 watt to 2.5 watts, and the calorific value of the second heat source is 5.0 watts to 7 The electronic device according to claim 1 or 2, which is in the range of 0.0 watts.
The electronic device according to claim 1 or 2, wherein the heat radiating sheet is arranged in contact with the bottom surface so that the planted chip component is embedded. The electronic device according to any one of claims 1 to 3, wherein the side surface and / or the bottom surface of the housing is provided with a hole leading to the inside of the housing for natural air cooling. The electronic device according to any one of claims 1 to 4, wherein the thick-walled component portion is provided with the hole in a part thereof. The electronic device according to any one of claims 1 to 5, wherein the first heat source is an external input / output terminal circuit structure module including a power amplifier, and the second heat source is a communication LSI. The back surface side of the printed circuit board arranged in the second heat source is a chip component is implanted, claim 1, the heat dissipation sheet as a chip component that is implanted is implanted is disposed in contact with the bottom surface The electronic device according to any one of 6 to 6. It is a heat dissipation structure composed of a housing having a bottom surface, a top surface provided with fins as a first heat sink and a hole leading to the inside of the housing, and side surfaces.
Place the first heat source in the housing with the top surface close to the area of the first heat sink where no holes are provided.
The second heat source is arranged adjacent to the first heat source in the housing and is configured to be arranged in the area where the hole exists in the upper space .
The second heat source is an electronic component having a height lower than that of the first heat source, and is a heat dissipation structure of an electronic device configured so that a space is provided between the second heat source and the upper part of the housing. And
The upper surface portion as the first heat sink is a heat dissipation structure of an electronic device configured to be thicker than the other constituent parts of the housing and to have a relatively large heat capacity. It is a heat dissipation structure having a second heat sink arranged in the housing close to the upper surface of the second heat source, and the upper surface of the second heat sink is arranged away from the upper surface provided with the hole. The heat dissipation structure of the electronic device according to claim 8 , which is configured in the above. The volume of the housing is 100 cubic centimeters or less, the calorific value of the first heat source is in the range of 1.0 watt to 2.5 watts, and the calorific value of the second heat source is 5.0 watts to 7 The heat dissipation structure of the electronic device according to claim 8 or 9 , which is in the range of 0.0 watts. The heat dissipation structure of the electronic device according to any one of claims 8 to 10, wherein a hole leading to the inside of the housing for natural air cooling is provided on the side surface and / or the bottom surface of the housing. The heat dissipation structure of the electronic device according to any one of claims 8 to 11, wherein the thick component portion is configured so that the hole is provided in a part thereof. The heat dissipation structure of the electronic device according to any one of claims 8 to 12, wherein the first heat source is an external input / output terminal circuit structure module including a power amplifier, and the second heat source is a communication LSI. The back side of the printed circuit board on which the second heat source is arranged is configured to implant chip parts, and the heat dissipation sheet is arranged in contact with the bottom surface so that the implanted chip parts are embedded. The heat dissipation structure of the electronic device according to any one of claims 8 to 13.

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