JP2017216271A - Electronic device and heat dissipation structure of electronic device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve such a problem that, if a plurality of heat sources generating high heat are provided at a high density, there is the case where heat cannot be sufficiently dissipated when a common heat dissipation path is used.SOLUTION: In an electronic device and a heat dissipation structure of an electronic device, a different heat dissipation path for each heat source is used. Specifically, a first heat dissipation path is provided so that heat of a first heat source (0321) is mainly released to the outside of a housing from a surface of fins (0324), as the first heat sink (0323), provided on the upper surface of the housing, the first heat source being disposed while the upper surface thereof is in proximity to an area where holes of the first heat sink are not provided; and a second heat dissipation path is provided so that heat of a second heat source (0322) disposed in proximity to the first heat source is mainly released through holes (0314) provided on the upper surface of the housing by natural convection in the housing.SELECTED DRAWING: Figure 3A

Description

  The present invention relates to an electronic device for efficiently radiating heat and realizing miniaturization in an electronic device having a high heating element in a narrow region, and a technology of the heat dissipation structure.

  In recent years, in order to reduce the size of electronic devices, modularization of electronic components housed in electronic devices has been progressing. Modularization does not require a step of arranging individual small electronic components on a substrate, and thus has an advantage that it is easy to manufacture an electronic device. However, since the heat generating components are integrated in the module, the amount of heat generated inside increases, and at the same time, the path for releasing the heat to the outside is limited, which causes a problem that the heat generated inside is difficult to be appropriately processed. Furthermore, since the problem of thermal failure such as malfunction or damage is likely to occur due to the mutual heat generated from a plurality of electronic components in the housing, a method for efficiently radiating heat in a limited space is required.

  Generally, heat dissipation methods for electronic devices include a method of releasing heat by forcibly creating an air flow by installing a fan, a method of promoting heat dissipation by arranging a heat sink in a heat source, and a fan and heat sink. Many heat dissipation methods are used. For example, Patent Document 1 discloses a cooling device in which a heat sink is arranged on a communication LSI. Patent Document 2 discloses a cooler for electronic components that radiates heat generated by the electronic components using a heat sink and an electric fan.

Japanese Patent Laying-Open No. 2015-50262 JP 2002-64171 A

  The above-mentioned Patent Document 1 provides a certain solution for both the heat radiation of the communication LSI and the downsizing of the cooling device. However, although the surface temperature of LSI, which is a heat source, can be lowered, there is a problem that the temperature of the housing surface rises because the heat is discharged into the housing of the electronic device. Moreover, in patent document 2, since the electric fan is used in addition to the heat sink, no solution is given for downsizing of the electronic device.

  Fans can forcibly cause an air flow in the electronic device and cool the inside, so that the fan can be installed with relatively no restrictions due to the location of the heat source or the shape of the heat source. In addition to the increase in size of the device, there were problems such as noise generation and maintenance. Further, since dust and the like are wound up in the electronic device, there is a problem that malfunction due to dust occurs.

  Therefore, in the present invention, even in electronic devices such as media converters, even if multiple electronic components that serve as heat sources are placed in the housing, it is possible to cool the heat sources in a narrow space by efficiently radiating heat with natural air cooling. An electronic device and a heat dissipation structure for an electronic device that do not cause thermal failure while providing a compact heat dissipation structure are provided.

  In order to solve the above problems, among the present inventions, a first invention is a housing having a bottom surface, a top surface provided with a fin as a first heat sink and a hole communicating with the inside of the housing, and a side surface. A first heat source disposed on the upper surface in the housing close to a region where the hole of the first heat sink is not provided, and a region disposed adjacent to the first heat source in the housing and having a hole in the upper space. An electronic device comprising a second heat source, a bottom surface, a top surface provided with a fin serving as a first heat sink and a hole leading to the inside of the housing, and a heat dissipation structure comprising a housing having a side surface The upper surface of the first heat source is disposed in the housing in the vicinity of the area where the hole of the first heat sink is not provided, and the second heat source is disposed adjacent to the first heat source in the upper space in the housing. Place it in the area where the hole exists Providing the heat radiation structure of an electronic device configured.

  Moreover, 2nd invention has a 2nd heat sink arrange | positioned close to the upper surface of a 2nd heat source within a housing | casing, and the upper surface of this 2nd heat sink is spaced apart from the upper surface in which the hole is provided. The electronic device according to claim 1 and the electronic device heat dissipation structure according to claim 9 are provided.

  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 watts to 2.5 watts, and the second heat source is in the range of 5.0 watts to 7. An electronic device according to claim 1 or 2 and a heat dissipation structure for an electronic device according to claim 9 or 10 which are in the range of 0 watt.

  The fourth aspect of the present invention is the electronic device according to any one of claims 1 to 3, and the electronic device according to any one of claims 9 to 11, wherein a hole leading to the inside of the casing for natural air cooling is provided on a side surface and / or a bottom surface of the casing. Provided is a heat dissipation structure for an electronic device.

  In addition, according to a fifth aspect of the present invention, the upper surface portion as the first heat sink is thicker than the other components of the housing and has a relatively large heat capacity. A heat dissipation structure for an electronic device according to any one of claims 9 to 12 is provided.

  The sixth aspect of the 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 constituent portion is provided with a hole in a part thereof.

  7. The electronic device according to claim 1, 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 as described in any one of Claim 9 to 14 is provided.

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

  Due to the electronic device and the heat dissipation structure of the electronic device according to the present invention, in an electronic device such as a media converter, even if a plurality of electronic components serving as a somewhat large heat source are installed in the housing, it is efficiently radiated by natural air cooling while achieving downsizing. It is possible to prevent thermal troubles such as malfunctions and damages. Furthermore, since an electric fan is not used, it is clean without raising dust and the like, maintenance is easy, and a long life and a low noise can be achieved.

Overall perspective view showing an example of an electronic device and its heat dissipation structure in Example 1 and Example 7 FIG. 3 is an entire perspective exploded view illustrating an example of an electronic device and a heat dissipation structure thereof in the first embodiment. The top view and sectional drawing which show an example of the electronic device in Example 1, and its heat dissipation structure The top view and sectional drawing which show an example of the electronic device in Example 1, and its heat dissipation structure The top view and sectional drawing which show an example of the electronic device in Example 1, and its heat dissipation structure The top view and sectional drawing which show an example of the electronic device in Example 1, and its heat dissipation structure The top view and sectional drawing which show an example of the electronic device in Example 1, and its heat dissipation structure Full perspective exploded view showing an example of an electronic device and its heat dissipation structure in Example 2 The top view and sectional drawing which show an example of the electronic device in Example 2, and its heat dissipation structure Full perspective exploded view showing an example of an electronic device and its heat dissipation structure in Example 4 Overall perspective view and cross-sectional view showing an example of an electronic device and its heat dissipation structure in Example 4 The whole perspective view of the housing | casing which shows an example of the electronic device in Example 4, and its heat dissipation structure, and sectional drawing of an electronic device Sectional drawing which shows an example of the electronic device in Example 4, and its heat dissipation structure The top view and sectional drawing which show an example of the housing | casing of the electronic device in Example 5, and its heat dissipation structure Overall perspective view showing an example of an electronic device and its heat dissipation structure in Example 6 Sectional drawing which shows an example of the electronic device in Example 6, and its heat dissipation structure Sectional drawing which shows an example of the electronic device in Example 8, and its heat dissipation structure Exploded view of whole surface showing an example of an electronic device and a heat dissipation structure thereof in Example 8

0110 Housing 0111,0211,1411,1511 Bottom surface 0112,0212,1512 Top surface 0113,0213,1513 Side surface 0214,0314,1514 Top surface hole 1515 Surface measurement hole 1516 Bottom surface hole 0217,0317 First heat sink on top surface of housing Area 0218, 0318 Area where holes on the upper surface of the housing exist 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 Fin 1525 2nd heat sink 0330 Plate 0331, 1531 Heat dissipation sheet 1
1532 Heat Dissipation Sheet 2
1433, 1533 Heat dissipation sheet 3
0141 External input / output terminal circuit structure module 0142 Communication LSI
0143, 1543 Printed circuit board 1444 Chip component 0145, 0245, 0345, 1545 Slot 0246 Hole on top of slot 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 scope of the invention. The relationship between the following examples and the claims is as follows. In the first embodiment, claims 1 and 9 will be mainly described. Example 2 is mainly related to claims 2 and 10, etc., Example 3 is mainly related to claims 3 and 11, etc., Example 4 is mainly related to claims 4 and 12, etc., and Example 5 is Mainly claims 5 and 13, etc., Example 6 is mainly related to claims 6 and 14, etc., Example 7 is mainly related to claims 7 and 15, etc., and Example 8 is mainly claimed. And 16 will be described.

<Concept of Example 1>

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

  FIG. 2 is an entire perspective exploded view illustrating an example of the electronic device and the heat dissipation structure thereof in the first embodiment, and is a conceptual diagram illustrating an example in which components of the electronic device according to the present invention are installed on a printed board. A first heat source (0221) that is an external input / output terminal circuit structure module and a second heat source (0222) that is a communication LSI are disposed adjacent to each other on a printed circuit board above the bottom surface of the housing. In FIG. 2, the first heat source is depicted as pointing to the slot (0245) for housing the external input / output terminal circuit structure module. It is what you point to. The upper surface of the housing is provided with fins (0224) as first heat sinks (0223) and holes (0214) communicating with 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, but the heat sink is composed of a plate portion and a fin serving as a base. In FIG. 2, a region (0217) where the hole of the first heat sink is not provided and a region (0218) where the hole (0214) exists are respectively surrounded by broken lines.

  3A to 3C are conceptual diagrams illustrating an example of the electronic device and the heat dissipation structure thereof 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 heat generated in the first heat source and the second heat source in Example 1 is shown in FIG. The direction of movement is indicated by an arrow. The first heat source (0321) is arranged close to the region (0317) where the upper surface of the first heat sink (0323) is not provided in the housing. 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) The upper surface of the housing can be constituted by both of them.

  The heat generated in the first heat source is naturally radiated 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 shown covered with a wavy line. Generally, in a heat sink having such fins, the heat transferred from the heat source is received by the plate portion of the heat sink. The cooling is performed by discharging from the fin surface having a large surface area.

  When the first heat sink is disposed in the housing, a space corresponding to the volume of the first heat sink is required in the housing. However, in the present invention, the first heat sink that is in contact with the first heat source is a part of the upper surface of the housing. Does not require space. Therefore, the height of the housing can be reduced, and as a result, the electronic device can be miniaturized. In this embodiment, in order to improve heat transfer, an example is shown in which a heat radiation sheet 1 (0331) is disposed between the first heat sink and the first heat source, and the first heat sink and the first heat source are in close contact. It is preferable to install a heat dissipation sheet.

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

  The second heat source (0322) is disposed adjacent to the first heat source in the housing and is disposed in a region (0318) where a hole exists in the upper space. As shown in FIGS. 3A and 3B, the heat generated by the second heat source is naturally radiated to the upper surface space of the second heat source, and is further moved from the upper surface space of the second heat source to the position facing the second heat source. Natural heat is radiated to the outside of the housing through a hole in the upper portion of the housing. The second heat source is an electronic component whose height is lower than that of the first heat source. Therefore, a space can be provided between the second heat source disposed adjacent to the first heat source and the upper portion of the housing. Since warmed air has the property of rising due to its low density, the heat exhausted from the second heat source rises inside the housing and then rises outside the housing through a hole provided on the top surface of the housing. To do. The second heat source can be naturally radiated by this air flow.

<Configuration of Example 1>
Again, the configuration of this embodiment will be described with reference to FIG. The “electronic device” of the present invention includes a bottom surface (0211), a top surface (0212) provided with a fin (0224) as a first heat sink (0223) and a hole (0214) communicating with the inside of the housing, 0213), a first heat source (0221) disposed on the upper surface of the housing in the vicinity of the region (0217) where the hole of the first heat sink is not provided, and the first heat source in the housing And a second heat source (0222) disposed in a region (0218) disposed adjacent to and having a hole in the upper space.

  The “electronic device heat dissipation structure” 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 a fin (0224) as a first heat sink (0223) and a hole (0214) communicating with the inside of the housing, and a side surface (0213) In the heat dissipation structure, the first heat source (0221) is disposed in the housing with the upper surface close to the area (0217) where the hole of the first heat sink is not provided, and the second heat source (0222) 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, a top surface provided with a fin as a first heat sink and a hole communicating with the inside of the housing, and a side surface. The housing is a box serving as an outer shell of the electronic device, and is configured to be able to store a substrate therein. The case of FIG. 2 is a box having a rectangular side surface and bottom surface, but is not limited thereto. However, a shape not suitable for the purpose of downsizing is not preferable. As the material forming the casing, SECC (electrogalvanized steel sheet) and aluminum which are not easily rusted are frequently used, but other metals and resins may be used. In this embodiment, SECC and aluminum are used.
A printed circuit board is disposed on the “bottom surface”. The printed circuit board is an electronic board on which a large number of electronic components are mounted, and on which various electronic circuits constituted by these electronic components are mounted. 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 a hole as a first heat sink and a hole communicating with the inside of the housing. The “fin” is provided as a first heat sink. The fin constitutes a first heat sink together with the base plate, and protrudes 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. The heat sink generally receives heat from the heating element at the plate portion and radiates heat from the fin surface.

  The area occupied by the plate of the first heat sink is preferably wider than the area of the upper surface of the first heat source. However, if it is too wide, miniaturization of the electronic device will be hindered. Therefore, it is preferable that it is at least as large as the area of the upper surface of the first heat source. Further, the contact surface between the first heat source and the plate does not need to be a horizontal surface, 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. Although the upper surface portion as the first heat sink will be described in detail in Example 5, it is preferable that the upper surface portion is thicker than the other components of the housing. As shown in FIG. 2, in the present embodiment, the region of the first heat sink is configured to be wider rearward in the longitudinal direction than the upper surface of the first heat source.

  1 to 15, plate-like straight fins are shown as fins, and the fins are arranged in parallel to each other in the longitudinal direction of the first heat source. The shape of the first heat sink is not limited to a plate-like straight fin, and may be, for example, a plurality of cylindrical pin fins from the viewpoint of improving 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 fin and the plate can be integrally formed of the same material as the plate by extrusion. Moreover, a fin and a plate may be formed by cutting, drawing, etc., and do not limit a processing method.

  As a material constituting the heat sink, aluminum and an aluminum alloy are preferably used, but other metal materials having high thermal conductivity such as copper and iron can also be used. Furthermore, it is preferable to perform alumite treatment, painting, etc. in order to improve the heat dissipation effect and corrosion resistance. In this embodiment, an alumite-treated aluminum heat sink integrally formed with a plate and fins is used as the first heat sink.

The “first heat source” is disposed in the casing so that the upper surface thereof is close to the region of the first heat sink. In addition, the heat dissipation structure for an electronic device of the present invention is configured such that the first heat source is disposed in the housing so that the upper surface 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 so as to affect each other. It is not excluded. “Arrangement” refers to arranging and fixing at a predetermined position.
Referring to FIG. 2, the first heat source (0221) is an external input / output terminal circuit structure module arranged by being inserted 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 or the like, and to protect the parts that are vulnerable to vibration from impacts. A space is formed at the front portion of the slot in the longitudinal direction so that an external input / output terminal can be inserted. In this embodiment, twelve 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 illustrating an example of an electronic device and a heat dissipation structure thereof in the first embodiment. 4A (a) is a plan view of the electronic device, FIG. 4A (b) is an AA ′ cross-sectional view of the electronic device, and FIG. 4A (c) is a BB ′ cross-sectional view of the electronic device. is there. The arrow in the figure shows an example of the direction in which heat is transmitted in the first embodiment. The heat generated in the first heat source is transmitted through the upper surface of the slot (0445) to the heat radiating sheet (0431) in contact with the slot and the heat radiated from the substantially circular hole (0446) on the upper surface of the slot. There are two ways of transmission to the heat dissipation sheet. Then, heat is transmitted from the heat radiation sheet to the plate portion (0430) of the first heat sink, and is radiated from the fin surface to the outside of the casing.

  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, the heat radiating sheet can be disposed in contact with the first heat source and the slot that houses the first heat source so that the heat radiating sheet is embedded in a substantially circular hole on the upper surface of the slot. An SFP + cable insertion slot (0447) is arranged in front of the first heat source.

  As shown in FIG. 4A (b), in the region of the first heat sink on the upper surface, the portion surrounded by the broken line in FIGS. 4A (a) and 4 (b) has a larger area in the longitudinal direction rearward than above the first heat source. It is also provided in a region 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 transmitted to the plate is also transmitted to the rear in the longitudinal direction of the plate and is released from the fins on the upper portion thereof, so that heat can be radiated more efficiently. Although not shown in detail in FIG. 4A (b), an electronic component that can be a heat source is arranged in the casing, although the amount of heat generated is not so high other than the first heat source and the second heat source. For example, as shown in FIG. 4A (b), heat generated by the electronic component 1 (0461) and the electronic component 2 (0462) can be transmitted to the first heat sink and released outside the housing.

  It is preferable that the first heat sink and the first heat source or the first heat sink, the first heat source, and the case (for example, a slot) housing the first heat source are closely attached with a heat radiating sheet to improve heat transfer. There are various methods for increasing the efficiency of heat transfer between the first heat sink and the first heat source or between the first heat sink and the first heat source and a case (for example, a slot) housing the first heat source. There is a method of indirectly reducing the heat transfer resistance of both of them by the adhesive force of the heat radiating sheet itself, or a method of using grease, a double-sided adhesive tape and an adhesive on the pressure bonding surface of the heat radiating sheet, the first heat sink and the first heat source is there. 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, attention should be paid to these heat conductivities. That is, the material is selected so that either transfer or heat conduction does not become another bottleneck. There is also a method of fixing a screw by dropping a foot from the first heat sink onto the printed circuit board. In this embodiment, as shown in FIGS. 3A, B (0331) and FIG. 4 (0431), an acrylic heat-sensitive adhesive sheet is disposed between the first heat sink and the first heat source to improve heat transfer. I am letting.

  The heat dissipating sheet is installed by crimping between a first heat source that needs to dissipate heat and a first heat sink. 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 are not completely brought into close contact with each other, and heat transfer is not easily performed between the first heat source and the first heat sink, which are electronic components. However, if a soft material is sandwiched between the two, they can be brought into intimate contact with each other to enhance heat transfer. Secondly, the shock received by the first heat sink (the upper surface of the housing) must be transmitted to the electronic component and damage the electronic component. However, if a soft material is sandwiched between the two, the first heat sink has received it. The impact is not directly transmitted to the electronic component, and the electronic component can be protected from the impact.

  A material for the heat-dissipating sheet is preferably soft, sticky, and high in thermal conductivity. In general, acrylic and silicon materials are often used. In addition, graphite or the like can be used. In the present embodiment, an example in which a heat radiation sheet of acrylic material having a width of 14 mm and a depth of 41 mm and an acrylic material is used is shown.

Referring again to FIG. 2, the “second heat source” (0222) is disposed in the region (0218) adjacent to the first heat source (0221) in the housing and having the hole (0214) in the upper space. To do. In FIG. 2, a region where a hole exists is surrounded by a broken line.
The heat dissipation structure for an electronic device according to the present invention is configured such that the second heat source is disposed adjacent to the first heat source in the housing and is disposed in a 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 disposed adjacent to each other.
“Arranged adjacent” 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 is not excluded and includes that other electronic components are arranged between the two regions. Further, in the present invention, specifically, it is determined that “adjacent to each other” is to be arranged at a position where they are affected by heat, that is, to be arranged in a space in the case with a distance within 10% of the width of the case. Are arranged ".

  FIG. 4B is a conceptual diagram illustrating an example of an electronic device and a heat dissipation structure thereof in 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 arrows in the figure show an example of the direction in which heat is transmitted in the first embodiment. The heat source of the second heat source (0422) is, for example, an electronic component in which a communication LSI is housed in a case, and the heat generation amount at the center portion is higher than the end portion due to its characteristics. The purpose of housing in the case is the same as the reason for housing the external input / output terminal circuit structure module of the first heat source in the slot. Further, an insertion port (0448) for a UTP or STP cable is arranged adjacent to the second heat source.

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

  In this embodiment, as shown in FIG. 4B (a), a substantially rectangular hole having a width of 2 mm and a length of 10 mm is formed at a position on the upper surface of the housing facing the second heat source, and spaced by 2 mm in the lateral direction. Three rows are arranged at intervals of 2 mm in the longitudinal direction. Of the region where the holes on the upper surface of the housing are present, the region (0451) forward in the longitudinal direction substantially 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. Released from the area. On the other hand, although the electronic component arrange | positioned at a longitudinal direction back is few compared with a 1st heat source and a 2nd heat source, it can become a heat source. The region (0452) on the rear side in the longitudinal direction contributes to the heat radiation of a part of the second heat source, but also on the heat radiation of the electronic component 3 (0463) and the electronic component 4 (0464) arranged on the rear side 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 by the first heat source (0421) is generated from the upper surface of the housing provided with the fins (0424) as the first heat sink. Natural heat is radiated directly from the outside 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 released to the outside through a hole (0414) on the upper surface of the housing provided at a position facing the second heat source. . Here, the space in which heat is released from each heat source is such that the first heat source is outside the housing and the second heat source is inside the housing, and the spaces from which heat is released are 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 transferred to the plate portion of the first heat sink via the heat dissipation sheet 1 (0431), and further released from the fin surface. In addition, the first heat source hardly exhausts heat to the space in the housing.

  Since the heat generated by the second heat source is released by the rising air flow generated by the temperature difference of the air generated at the upper part of the second heat source, it is easily affected by a slight air flow. However, there is almost no heat radiation from the first heat source to the inside of the housing, and an air flow from other heat sources is hardly generated. By adopting such a heat dissipation structure, it is possible to radiate the heat generated by the first heat source and the second heat source from the narrow housing to the outside.

  The electronic device and the heat dissipation structure of the electronic device of Example 1 can radiate the 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 electronic device can be downsized.

<Concept of Example 2>
FIG. 5 is an overall perspective exploded view illustrating an example of an electronic device and a heat dissipation structure thereof according to the second embodiment of the present invention, and is a conceptual diagram illustrating an example when components of the electronic device according to the second embodiment are installed on a printed board. is there. The electronic device of Example 2 and the heat dissipation structure of the electronic device differ from Example 1 in that the second heat sink (0525) and the heat dissipation sheet 2 (0532) are provided based on the electronic device and electronic device of Example 1. 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 holes.

  For example, a method of dissipating the heat generated by the second heat source using a heat sink provided on the upper surface of the housing similarly to the first heat source is also conceivable. However, since the second heat source is a component having a low height by nature, some medium is required to transfer the heat to the heat sink on the upper surface of the housing. Although it is possible to use a metal plate such as a copper plate with high thermal conductivity or a heat-dissipating sheet as a medium, such a medium requires a certain amount of height in the housing, which increases the weight of the electronic device and the cost. There may be a problem in that Therefore, in this embodiment, the second heat sink is disposed close to the second heat source, the heat generated by the second heat source is naturally radiated to the upper surface of the second heat source via the second heat sink, and the upper surface of the housing It was set as the structure discharged | emitted from a hole. The present invention is characterized in that two heat sinks are arranged in different spaces and have two heat dissipation paths. Hereinafter, a description will be given with reference to FIG.

  FIG. 6A is a conceptual diagram illustrating an example of an electronic device and a heat dissipation structure thereof in the first embodiment. 6A (b) is a plan view of the electronic device, FIG. 6A (a) is an AA ′ sectional view of the electronic device, and FIG. 6A (c) is a BB ′ sectional view of the electronic device. is there. The arrow in the figure shows an example of the direction in which heat is transmitted in the embodiment. In the second embodiment, since the second heat sink (0625) is provided, the heat radiation path of the heat generated in the first heat source is different from that in the first embodiment. The heat generated in the second heat source is released from the fin surface to the upper space of the second heat source through the heat radiating sheet 2 (0632) and the plate of the second heat sink adjacent to the second heat source. Natural heat is radiated to the outside of the housing through a hole (0614) in the upper portion of the housing provided at a position facing the heat source.

  In this embodiment, as shown in FIG. 6B (a), a substantially rectangular hole having a width of 2 mm and a length of 10 mm is formed at a position of 2 mm in the lateral direction at the position of the upper surface of the casing facing the second heat source and the second heat sink. 5 rows and 3 rows at 2 mm intervals in the longitudinal direction. Of the region where the hole on the upper surface of the housing exists, the region (0651) forward in the longitudinal direction substantially coincides with the region occupied by the second heat source and the second heat sink, so that the heat generated by the second heat source is the same. Most is released from this area. Since the region behind the longitudinal direction (0652) has the same configuration as that of the first embodiment, the description thereof is omitted.

<Configuration of Example 2>
In the electronic device and the heat dissipation structure of the electronic device according to the second embodiment, the “second heat sink” is disposed in the housing in the vicinity of the upper surface of the second heat source, and the upper surface of the second heat sink is a hole. Is arranged so as to be separated from the upper surface of the casing in which the is provided.

  In the second heat sink disposed close to the second heat source, heat is transferred from the second heat source to the plate of the second heat sink, and is further released from the fin surface. In the second heat sink, natural convection of air occurs. Natural convection is a flow generated only by buoyancy caused by a temperature difference between fluids in a state where there is no factor that causes a flow such as a fan.

  In this embodiment, since the second heat sink and the casing are arranged so as to be separated from each other, the natural convection generated in the second heat sink causes natural heat dissipation from the upper surface of the casing in which the hole on the upper surface of the second heat sink is provided. Is 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. It is not preferable that the second heat sink and the housing are in contact with each other because natural convection is prevented from occurring. In addition, heat transfer from the fin to the first heat sink on the upper surface of the housing occurs at the contact portion, and the total amount of heat that must be dissipated by the first heat sink becomes excessive, and the heat generated by the first heat source and the second heat source is sufficiently generated. Since it becomes impossible to process, it is not preferable.

  In the second embodiment, two heat sinks are configured. The second heat sink is disposed in the housing, whereas the fins of the first heat sink are in contact with the air outside the housing. Thus, 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 it difficult to cool, but the second heat sink radiates heat from the fin surface inside the housing, and the first heat sink fin radiates heat outside the housing. The heat dissipation 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, description thereof is omitted. However, if the fin pitch is too narrow, natural convection hardly occurs and heat is trapped. Therefore, it is preferable that the fin pitch is wide enough to cause heat transfer. In this embodiment, a 6 × 6 pin fin is used as the second heat sink, 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. Is used with alumite treatment.

  The second heat sink and the second heat source are preferably adhered to each other with a heat radiating sheet or the like in the same manner as the first heat sink and the first heat source of Example 1 to improve heat transfer. In the present embodiment, an example in which a heat radiation sheet having a width of 21 mm and a depth of 21 mm and an acrylic material of 1 mm thickness is used is shown. Other configurations including the heat dissipation sheet are the same as those in the first embodiment, and thus the description thereof is omitted.

<Effect of Example 2>
As shown in FIG. 6, the second heat sink is disposed in the casing close to the upper surface of the second heat source, and the upper surface of the second heat sink is separated from the upper surface of the casing in which the holes are provided. 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, and the heat of the plate is discharged from the fin surface to the upper space of the second heat source, and further, the position facing the second heat source. Natural heat is radiated to the outside of the housing through a hole in the upper portion of the housing. Due to the arrangement of the second heat sink, the heat generated in the second heat source is promoted to the upper part of the second heat source, and as a result, the heat radiation to the outside of the housing is promoted.

<Concept of Example 3>
The electronic device of Example 3 and the heat dissipation structure of the electronic device are based on the electronic device of Example 1 or Example 2 and the heat dissipation structure of the electronic device, 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.

<Configuration of Example 3>
In the electronic device and the heat dissipation structure of the electronic device of Example 3, 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 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 desirably 75 cubic centimeters or less. The size of the housing of Example 3 is, for example, a width of 50 mm, a length of 74 mm, a height of 20 mm, and a volume of 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 Example 1 and Example 2 and the heat dissipation structure of the electronic device.

<Effect of Example 3>
Even if the housing is small, a special heat dissipation structure is not required if the heat source is sufficiently small. On the other hand, even if a certain amount of heat source is large, if the casing is enlarged and the heat source is sufficiently separated, thermal failure is unlikely to occur. According to Example 3 based on the electronic device of Example 1 or Example 2 and 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 watt, it is possible to constitute an electronic device and a heat dissipation structure of the electronic device that do not cause thermal failure with a small size of 74 cubic centimeters.

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

FIG. 8 is a conceptual diagram of an overall perspective view (a) and a cross-sectional view (b) illustrating an example of an electronic device and a heat dissipation structure thereof according to the fourth embodiment. The direction in which the heat generated by the first heat source and the second heat source in Example 4 is transmitted is indicated by arrows. As shown in FIG. 8, air having a relatively low temperature flows in from the hole (0815) on the side surface of the casing, and the air heated by the heat source passes through the hole (0814) provided on the upper surface of the casing to the outside. Since the flow of being discharged occurs, natural heat dissipation of the electronic device can be performed more efficiently.
The

  FIG. 9 is a conceptual diagram of an entire perspective view of a casing and a cross-sectional view of the electronic device showing an example of the electronic device and the heat dissipation structure thereof in the fourth embodiment. The direction of heat transfer in Example 4 is indicated by arrows. FIG. 9A shows an example of the arrangement of the holes (0916) on the bottom surface of the housing. FIG. 9B is a cross-sectional view of a portion having a hole in the bottom surface. As shown in FIGS. 9A and 9B, air having a relatively low temperature passes through the hole in the bottom surface to the back surface side of the printed circuit board. Flows in and cools the back side of the printed circuit board. In addition, the air that flows in through the hole in the bottom surface rises through the gap between the printed circuit board and the side of the housing, and flows out of the housing through the hole in the top surface of the housing. It can be done more efficiently.

  FIG. 10 is a conceptual diagram of a cross-sectional view illustrating an example of an electronic device and its heat dissipation structure in Example 4. The direction in which heat is transferred when holes are provided in the surface measurement and bottom surface in Example 4 is indicated by arrows. By providing the hole (1015) on the side surface and the hole (1016) on the bottom surface, as shown in FIG. 10, air flows from the hole on the bottom surface and rises through the gap between the printed circuit board and the side surface of the housing. As a result, a good flow is produced in which the air flows in from the holes on the side surface and flows out from the holes on the upper surface of the housing to the outside of the housing, so that more efficient natural heat dissipation can be performed.

<Configuration of Example 4>
The electronic device of Example 4 and the heat dissipation structure of the electronic device are provided with holes that communicate with the inside of the case for natural air cooling on the side and / or bottom of the case. “Natural air cooling” refers to cooling in a non-winding state in which no wind is forcibly received from others, and cooling using forced air 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 that can withstand a certain amount of impact from the upper surface, it is not preferable that the shape that is too large or the region occupied by the hole is too wide. Since it is preferable to generate an air flow as shown in FIG. 8 and FIG. 10, the side hole is preferably a substantially oblong or oblong shape, and the width is about 0.5 to 2 mm. Is preferably about 10 to 15 mm. Moreover, in order to make it difficult for foreign matters, such as dust, to enter from the outside, the thickness 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. Furthermore, in order to promote heat dissipation, it is desirable to provide at a position close to the first heat source and the second heat source.

  The bottom surface is not subjected to a load such as the weight of the top surface, and dust and the like are less likely to enter. Therefore, the bottom surface can be provided without restrictions on the shape, size, number, and the like 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 if it is a vertically long substantially rectangular or substantially elliptical shape.

<Effect of Example 4>
By providing holes on the side surface and / or bottom surface of the casing that lead to the inside of the casing for natural air cooling, the heat generated in the first heat source and the second heat source is generated from the upper surface of the casing shown in the first to third embodiments. In addition to heat dissipation from the bottom, air with relatively low temperature flows in from the bottom hole and bottom hole, and a good flow of air flows out from the hole on the top surface of the housing to the outside of the housing. It is promoted and the heat dissipation action is further enhanced.

<Concept of Example 5>
The electronic device of Example 5 and the heat dissipation structure of the electronic device are based on the electronic device of Example 1 to 4 and the heat dissipation structure of the electronic device, and the upper surface portion as the first heat sink is more than the other components of the casing. Is also thick and has a relatively large heat capacity.

<Configuration of Example 5>
FIG. 11 is a conceptual diagram illustrating an example of a housing of an electronic device and a heat dissipation structure thereof according to the fifth embodiment. 11A is a plan view of the electronic device, FIG. 11B is a cross-sectional view taken along the line AA ′ of the electronic device, and FIG. 11C is a cross-sectional view taken along the line BB ′ of the electronic device. It is. As shown in FIG. 13 and FIG. 13, the electronic device and the heat dissipation structure of the electronic device according to the present example are such that the upper surface portion as the first heat sink (1123) is the other components of the casing (FIG. 11B and FIG. It is characterized in that it is thicker and has a relatively large heat capacity than the portion indicated by shading in (c).

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

<Effect of Example 5>
The upper surface portion as the first heat sink is thicker than the other components of the housing and has a relatively large heat capacity, so that efficient heat dissipation can be performed as described above. In addition, since the heat capacity of the upper surface portion of the housing is relatively larger than the other components of the housing, the upper surface portion of the housing can retain a lot of heat, so heat radiation from the upper surface becomes the mainstream. Therefore, it is possible to prevent heat from being trapped inside the housing, and to reduce the influence of the heat of the electronic components in the housing. Therefore, it is possible to provide an electronic device and a heat dissipation structure for the electronic device that do not cause a thermal failure with a small size.

<Concept of Example 6>
The electronic device of Example 6 and the heat dissipation structure of the electronic device are based on the electronic device of Example 5 and the heat dissipation structure of the electronic device, and the thick constituent parts are provided with fins as the first heat sink, and one of them. The part is provided with a hole.

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

  FIG. 13 is a conceptual diagram of a cross-sectional view illustrating an example of an electronic device and a heat dissipation structure thereof in Example 6, and FIG. 13A is a cross-sectional view of a portion provided with a hole, and FIG. FIG. 5 is a cross-sectional view of a portion where no hole is provided. The direction in which heat is transmitted in Example 6 is indicated by arrows. As shown in FIG. 13A, most of the heat generated in the first heat source is radiated from the fin surface of the first heat sink located on the upper surface of the first heat source. The heat generated by the second heat source is naturally radiated mainly from a 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 in the second heat source is also transmitted to the upper surface portion at a position facing the second heat source and not provided with a hole. The heat can be radiated 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 via the plate of the first heat sink, and can be further radiated from the fins. Further, part of the heat generated by the second heat source is transmitted to the plate of the first heat sink and can be further radiated from the fins.

<Effect of Example 6>
The electronic device of Example 6 and the heat dissipation structure of the electronic device are based on the electronic device of Example 5 and the heat dissipation structure of the electronic device, and the thick constituent parts are provided with fins as the first heat sink throughout. Further, heat radiation from the fin surface is added, and efficient heat radiation 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 electronic device of Examples 1 to 6 and the heat dissipation structure of the electronic device, 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.

<Configuration 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 the present 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. 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 for sending information to the outside, including a circuit. It is a structure. The “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.

  An electronic device generally has a large number of electronic components arranged on a substrate, but a special heat dissipation structure is not required if the housing is sufficiently large even if each electronic component generates heat. . However, increasing the size of the housing is contrary to the miniaturization generally required of electronic devices, and is difficult to accept in the electronic device market. A configuration in which electronic parts are box-shaped or modularized and accommodated in a case such as a slot can reduce the size of the entire product, rather than arranging individual parts on a substrate. Furthermore, there is an advantage that the manufacturing process becomes easy.

  However, boxing and modularization of electronic components means that 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 individual electronic components that are not modularized are cooled, the structure of the electronic device becomes complicated because it is necessary to construct a heat dissipation structure corresponding to each electronic component with a different size, shape, and amount of heat generated. Problem arises. In this regard, the present invention efficiently dissipates heat by constructing a heat radiation structure integrated by boxing or modularization, thereby enabling downsizing of the entire electronic device.

<Effect of Example 7>
The first heat source according to the present embodiment is an external input / output terminal circuit structure module including a power amplifier, the second heat source is an electronic device that is a communication LSI, and the heat dissipation structure of the electronic device is the same as that of the first to sixth embodiments. By using the heat dissipation structure of the device and the electronic device as a basis, it is possible to configure an electronic device and a heat dissipation structure of the electronic device that do not cause a thermal failure with a small size.

<Concept of Example 8>
The electronic device of Example 8 and the heat dissipation structure of the electronic device are based on the electronic device of Examples 1 to 7 and the heat dissipation structure of the electronic device, and chip parts are implanted on the back side of the printed board on which the second heat source is arranged. The heat-dissipating sheet is disposed in contact with the bottom surface so that the embedded chip component is embedded.

<Configuration of Example 8>
FIG. 14 is a conceptual diagram of a cross-sectional view illustrating an example of an electronic device and its heat dissipation structure in Example 8. The direction in which heat is transmitted in Example 8 is indicated by arrows. FIG. 14B is an enlarged view of a part of FIG. 14A including chip parts implanted on the back side of the printed circuit board. As shown in FIG. 14, chip parts (1444) are implanted on the back side of the printed circuit board (1443) on which the second heat source (1422) is arranged so that the implanted chip parts are embedded. The heat dissipation sheet 3 (1433) is disposed in contact with the bottom surface (1411) to improve heat transfer. Since the structure of the heat dissipation sheet is the same as that of the first embodiment, the description thereof is omitted. Chip parts are implanted on the back side of the printed circuit board on which the second heat source is arranged, and the chip parts can also serve as heat sources. In addition, it is necessary to release heat transferred from the second heat source through the printed circuit board to the outside of the housing. By disposing the heat dissipation sheet so that the chip component implanted 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 disposed, the printed circuit board from the chip component and the second heat source is arranged. The heat transmitted through the heat transfer sheet can be transmitted to the bottom surface using the heat radiating sheet as a medium.

  When the heat dissipating sheet is arranged, the heat generated by the chip component is quickly transmitted to the bottom surface of the housing in contact with the heat dissipating sheet. In FIG. 14A, the heat radiation path of the heat transmitted to the bottom surface is indicated by a broken arrow, and the heat is radiated from the surface of the housing while conducting in the housing. A part of the heat is transmitted from the housing to the first heat sink and is radiated from the fin surface.

  On the other hand, when the heat dissipation sheet is not disposed, the heat generated by the chip component is discharged through two paths. One is that heat transferred to the bottom surface of the housing by radiation or slight natural convection that occurs in a narrow space on the back side of the printed circuit board is conducted in the housing and released from the surface of the housing. A part of the heat can also be radiated from the first heat sink on the upper surface of the housing. The other is a path that is discharged along with the flow of air rising upward from the gap between the side surface of the housing and the printed board. 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 provided, and heat tends to stay at the bottom of the printed circuit board. By arranging the heat dissipation sheet as shown in the present embodiment, heat retention on the back side of the printed circuit board is eliminated.

  The configuration of the heat dissipation sheet is omitted because it is the same as that of the first embodiment, but in this embodiment, an example in which a heat dissipation sheet having a width of 13 mm and a depth of 17 mm and an acrylic material of 2 mm is used is shown. In the second heat source, heat generation at the central portion concentrates, so that the heat radiation sheet and the back 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 an entire perspective exploded view showing an example of an electronic device and a heat dissipation structure thereof in Example 8, and is a conceptual diagram showing an example of a 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 first heat sinks (1523). Although not shown in the drawing, the upper surface portion as the first heat sink is thicker than the other components 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 the surface side of the printed circuit board above the bottom surface of the housing. The first heat source is disposed in the vicinity of a region where the hole of the first heat sink is not provided in the housing. It is preferable that a heat radiating sheet 1 (1531) is provided between the first heat sink and the first heat source or between the first heat sink and the first heat source and a case (for example, a slot) for housing the first heat source. In FIG. 15, the first heat source is depicted as pointing to the slot (1545) for housing the external input / output terminal circuit structure module. It is what you point to.

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

<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 implanted on the back side of the printed circuit board on which the second heat source is arranged. By disposing the sheet in contact with the bottom surface, the heat radiation from the chip component can be efficiently discharged, so that it is possible to configure an electronic device and a heat dissipation structure of the electronic device that do not cause thermal failure with a small size. . In addition, by sandwiching a heat-dissipating 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 component, and the electronic component can be protected from the impact. .

Claims (16)

A housing having a bottom surface, a top surface provided with a fin as a first heat sink and a hole leading to the inside of the housing, and a side surface;
A first heat source disposed close to a region where the hole of the first heat sink is not provided on the upper surface in the housing;
A second heat source disposed in a region adjacent to the first heat source and disposed in an area in which the hole exists in the upper space;
An electronic device consisting of   A second heat sink disposed close to the upper surface of the second heat source in the housing, wherein the upper surface of the second heat sink is disposed so as to be separated from the upper surface provided with the hole. The electronic device described.   The volume of the enclosure is 100 cubic centimeters or less, 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. The electronic device according to claim 1 or 2.   The electronic device according to any one of claims 1 to 3, wherein a hole leading to the inside of the housing for natural air cooling is provided on a side surface and / or a bottom surface of the housing.   5. The electronic device according to claim 1, wherein a portion of the upper surface serving as the first heat sink is thicker than other components of the housing and has a relatively large heat capacity.   The electronic device according to claim 5, wherein the thick component portion is provided with the 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.   The chip part is planted on the back surface side of the printed circuit board on which the second heat source is disposed, and the heat dissipation sheet is disposed in contact with the bottom surface so that the implanted chip part is embedded. The electronic device according to any one of 7 to 7. A heat dissipating structure comprising a bottom surface, a top surface provided with a fin as a first heat sink and having a hole leading to the inside of the housing, and a side surface,
Arrange the first heat source in the housing close to the area where the hole of the first heat sink is not provided,
A heat dissipation structure for an electronic device configured to dispose a second heat source adjacent to the first heat source in a housing and disposed in a region where the hole exists in the upper space.   A heat dissipation structure having a second heat sink disposed in proximity to the upper surface of the second heat source in the housing, wherein the upper surface of the second heat sink is disposed away from the upper surface provided with the hole. The heat dissipation structure for an electronic device according to claim 9, which is configured as follows.   The volume of the enclosure is 100 cubic centimeters or less, 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. The heat dissipation structure for an electronic device according to claim 9 or 10.   The heat dissipation structure for an electronic device according to any one of claims 9 to 11, wherein holes are formed in a side surface and / or a bottom surface of the housing so as to communicate with the housing for natural air cooling.   13. The electronic device according to claim 9, wherein a portion of the upper surface as the first heat sink is thicker than other components of the housing and is configured to have a relatively large heat capacity. Heat dissipation structure.   The heat dissipation structure for an electronic device according to claim 13, wherein the thick component portion is configured such that the hole is provided in a part thereof.   15. The electronic device heat dissipation structure according to claim 9, 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 embedded chip parts are embedded. The heat dissipation structure for an electronic device according to any one of claims 9 to 15, which is configured as follows.

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