JP2018142055A - Heat sink, circuit board and radio communication apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently dissipate heat from a heat source included in a radio communication apparatus.SOLUTION: A heat sink is provided on a circuit board formed with an antenna and a ground pattern which is used to operate the antenna with a predetermined property and is adjacent to a circumference of a surface formed by the antenna excluding one direction. The heat sink is thermally connected to a heat source on the circuit board and at least partially faces a surface formed by the ground pattern.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a technology for radiating heat generated in a heat source included in a wireless communication device.

  With the progress of miniaturization of wireless communication devices, miniaturization of antennas is required. In portable wireless communication devices such as mobile phones and smartphones, an antenna is often mounted inside a housing. Therefore, an antenna that can be formed on a circuit board (hereinafter referred to as “pattern antenna”) has been developed.

  Examples of techniques related to pattern antennas are disclosed in Patent Documents 1 to 5. The antennas of Patent Documents 1 to 5 can be formed on a circuit board. However, the antennas of Patent Documents 1 to 5 occupy an area that cannot be ignored on the circuit board.

  An example of a technique for downsizing an antenna element in a pattern antenna is disclosed in Patent Document 6. In the printed circuit board of Patent Document 6, the conductor pattern on the printed circuit board forms a split ring resonator. In the printed circuit board of Patent Document 6, the split ring resonator is formed at an intermediate portion of a certain side of the printed circuit board, and is surrounded by a ground pattern in three directions where the certain side does not exist.

  Hereinafter, an antenna including a split ring resonator formed as a conductor pattern on a circuit board is referred to as a “micro split ring antenna”.

JP 2013-121004 A JP 2011-151560 A JP 2009-194783 A JP 2008-124617 A JP 2007-082037 A WO2014 / 132519

  With the progress of miniaturization and higher functionality of wireless communication devices, heat generation in heat sources such as processors and power supply ICs (Integrated Circuits) included in the wireless communication devices has increased. In portable wireless communication devices such as mobile phones and smartphones, heat is often released by natural cooling using a heat sink or the like without using a blower fan or the like. Therefore, in the wireless communication device, the efficiency of heat dissipation is a problem.

  However, in the techniques of Patent Documents 1 to 6, in the heat radiation from the heat source included in the wireless communication device, the antenna characteristics on the front surface side and the back surface side of the circuit substrate facing the surface formed by the antenna on the circuit substrate are Since it has an effect, a heat sink cannot be installed. In the techniques of Patent Documents 1 to 6, the antenna portion on the circuit board is not effectively used as a heat diffusion destination. Therefore, the techniques of Patent Documents 1 to 6 have a problem that the efficiency of heat dissipation is insufficient.

  The present invention has been made in view of the above-described problems, and has as its main object to improve the efficiency of heat radiation from a heat source included in a wireless communication device.

  In one embodiment of the present invention, the heat sink is provided on a circuit board on which an antenna and a ground pattern adjacent to each other except for one direction are formed around a surface formed by the antenna, which is used to operate the antenna with predetermined characteristics. A heat sink, which is thermally connected to a heat source on the circuit board and faces at least a part of the surface on which the ground pattern is formed.

  In one embodiment of the present invention, a circuit board includes an antenna, a ground pattern adjacent to the surface formed by the antenna except for one direction, a heat source, and a heat source. And a heat sink that is connected to each other and that faces at least a portion of the ground pattern.

  In one embodiment of the present invention, a wireless communication device includes an antenna, a ground pattern adjacent to the surface formed by the antenna except for one direction, a heat source, and a heat source. A heat sink that is thermally connected and that faces at least a part of the surface on which the ground pattern is formed is provided.

  ADVANTAGE OF THE INVENTION According to this invention, there exists an effect that the thermal radiation from the heat source contained in a radio | wireless communication apparatus can be made efficient.

It is a three-plane figure which shows an example of a structure of the radio | wireless communication apparatus in the 1st Embodiment of this invention. It is a perspective view which shows an example of a structure of the heat sink contained in the radio | wireless communication apparatus in the 1st Embodiment of this invention. It is a three-view figure which shows the structure of the radio | wireless communication apparatus which is a comparison object for comparing with this embodiment. It is a perspective view which shows the structure of the heat sink contained in the radio | wireless communication apparatus which is a comparison object for comparing with this embodiment. It is the figure which simulated the temperature distribution of the radio | wireless communication apparatus in the 1st Embodiment of this invention, and the radio | wireless communication apparatus of a comparison object. It is a table | surface which shows the simulation result of the temperature of the radio | wireless communication apparatus in the 1st Embodiment of this invention, and the radio | wireless communication apparatus of a comparison object. It is a perspective view which shows an example of the structure of the heat sink contained in the modification of the radio | wireless communication apparatus in the 1st Embodiment of this invention. It is a double view which shows an example of a structure of the radio | wireless communication apparatus in the 2nd Embodiment of this invention. It is a perspective view which shows an example of a structure of the heat sink contained in the radio | wireless communication apparatus in the 2nd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings, equivalent components are denoted by the same reference numerals, and description thereof will be omitted as appropriate.
(First embodiment)
A configuration in the present embodiment will be described.

  FIG. 1 is a three-view diagram illustrating an example of a configuration of a wireless communication apparatus according to the first embodiment of the present invention. More specifically, the upper diagram is a top view of components existing on the upper surface of the circuit board included in the wireless communication device as seen transparently from above. The middle diagram is a top view of the components existing on the bottom surface of the circuit board included in the wireless communication device as seen transparently from above. Further, the lower drawing is a side view of the components included in the wireless communication device as seen transparently from the side.

  The wireless communication device 400 in the present embodiment is, for example, a mobile phone, a smartphone, a tablet terminal, a notebook PC, a television, or a camera having a wireless communication function. The wireless communication device 400 includes a circuit board 300 and a heat sink 100.

  The circuit board 300 includes an antenna 200, a ground pattern 330, and a heat source.

  The antenna 200 is formed on the circuit board 300 as a conductor pattern (pattern antenna). In order for the antenna 200 to operate with predetermined characteristics, a ground pattern needs to be formed around the surface formed by the antenna 200 except for one direction. The antenna 200 is, for example, a micro split ring antenna. In FIG. 1, an antenna 200 is a portion where a C-shaped conductor pattern (split ring) is formed. In the micro split ring antenna, the conductor pattern forming the split ring resonator may be multilayered. The antenna 200 is formed, for example, at an intermediate portion of the side 360 of the circuit board 300.

  The ground pattern 330 is formed on the upper surface side of the circuit board 300 in regions adjacent to the antenna 200 on both sides of the antenna 200 and inside the circuit board 300. The ground pattern 330 may be electrically connected to another ground pattern or a housing.

  The heat source is a heat source mounted on the circuit board 300. The heat source is, for example, the processor 310 or the power supply IC 320. Hereinafter, an example in which the heat sink 100 radiates heat from the processor 310 that is a main heat source will be described. However, the heat radiated by the heat sink 100 according to the present embodiment is not limited to the processor 310.

  The heat sink 100 radiates the heat conducted from the heat source to the surroundings. A heat conductive sheet 110 may be inserted between the heat sink 100 and the heat source. The heat sink 100 may be thermally connected to the ground pattern 330, another ground pattern, or the housing.

  FIG. 2 is a perspective view showing an example of the configuration of the heat sink included in the wireless communication apparatus according to the first embodiment of the present invention. More specifically, FIG. 2 is a perspective view of the heat sink 100 as viewed obliquely from above.

  When the heat sink 100 is installed on the circuit board 300, the heat sink 100 is parallel to the circuit board 300 at a part of the position on the surface side of the circuit board 300, which is adjacent to both sides of the antenna 200 and faces the surface formed by the ground pattern 330. Has a plate part 150 installed on the surface. The plate portion 150 does not have a plate portion (a notch portion 190 is formed) at a position on the surface side of the circuit board 300 that faces the surface formed by the antenna 200 when installed on the circuit board 300.

  The heat sink 100 further includes a plate part 140 and a side part 130. The plate part 140 is thermally connected to a heat source. The plate part 150 and the plate part 140 constitute the plate part 120. The side surface portion 130 may have a function of fixing the circuit board 300 to the housing of the wireless communication device 400.

  In the above description, the configuration in which the heat sink 100 has the plate portion on the front surface side of the circuit board 300 has been described. However, the heat sink 100 has the same plate portion and cutout portion on the lower surface side of the circuit board 300 as those on the upper surface side. You may have.

  The operation in this embodiment will be described. Specifically, the result of the temperature simulation in the wireless communication device 400 and the wireless communication device to be compared will be described.

  In the temperature simulation, the wireless communication apparatus 400 has the configuration shown in FIGS.

  FIG. 3 is a three-view diagram illustrating a configuration of a wireless communication apparatus that is a comparison target for comparison with the present embodiment. More specifically, the upper diagram is a top view of components existing on the upper surface of the circuit board included in the wireless communication device as seen transparently from above. The middle diagram is a top view of the components existing on the bottom surface of the circuit board included in the wireless communication device as seen transparently from above. Further, the lower drawing is a side view of the components included in the wireless communication device as seen transparently from the side.

  A wireless communication device 409 that is a comparison target includes a circuit board 309 and a heat sink 109.

  The circuit board 309 includes an antenna 209 and a heat source.

  The antenna 209 is formed on the circuit board 309 as a conductor pattern (pattern antenna).

  The antenna 209 includes the side 360 of the circuit board 309 as a boundary, and occupies the entire short side direction of the circuit board 309.

  The heat sources are the processor 310 and the power supply IC 320 mounted on the circuit board 309.

  FIG. 4 is a perspective view illustrating a configuration of the heat sink 109 included in the wireless communication apparatus 409 that is a comparison target for comparison with the present embodiment. More specifically, FIG. 4 is a perspective view of the heat sink 109 as viewed obliquely from above.

  The heat sink 109 includes a plate portion 129 and a side surface portion 139. The plate portion 129 exists on the upper surface side of the circuit board 309 and is thermally connected to the processor 310 that is a heat source. The plate part 129 has the same shape as the plate part 140 of the wireless communication device 400. The side surface portion 139 has the same shape as the side surface portion 130 of the wireless communication apparatus 400. However, the heat sink 109 does not have a plate portion at a position facing the surface formed by the antenna 209 when installed on the circuit board 309. This is because the plate portion of the heat sink 109 cannot be installed on the front surface side and the back surface side of the circuit board 309 facing the surface formed by the antenna 209 because the characteristics of the antenna 209 are affected. That is, since the heat sink 109 has a smaller surface area than the heat sink 100, the heat dissipation efficiency is lower than that of the heat sink 100.

  Other configurations of the wireless communication device 409 are the same as the configurations of the wireless communication device 400 illustrated in FIGS. 1 and 2.

  The simulation conditions in the temperature simulation are as follows.

  The antenna 200 is a micro split ring antenna. The size of the antenna 200 is 10 mm in length and 14 mm in width.

  The antenna 209 is an inverted L antenna. The antenna 209 has substantially the same characteristics and performance as the antenna 200. The size of the antenna 209 is 20 mm in length and 30.8 mm in width.

  The thermal conductivity is 10 W / m · K for the processor 310, 398 W / m · K for the circuit boards 300 and 309 (copper pattern portion), 236 W / m · K for the heat sinks 100 and 109 (aluminum), and the thermal conduction sheet 110. Is 2 W / m · K.

  It is assumed that the heat generation amount of the processor 310 is 1.78 W and the heat generation amount of the power supply IC is 0.8 W.

  The ambient temperature of the wireless communication devices 400 and 409 is 40 degrees C.

  FIG. 5 is a diagram simulating temperature distributions of the wireless communication apparatus 400 and the comparison-target wireless communication apparatus 409 according to the first embodiment of the present invention. The left figure shows the surface temperature distribution of the wireless communication apparatus 400, and the right figure shows the surface temperature distribution of the wireless communication apparatus 409. The left and right diagrams are perspective views of the casing as viewed from below (the side where the power supply IC 320 is located), in which differences in temperature on the casing surfaces of the wireless communication apparatuses 400 and 409 are represented by differences in shading. The right front side of the housing is the side where the antenna is installed.

  As shown in FIG. 5, the temperature near the antenna 200 in the wireless communication device 400 is higher than the temperature near the antenna 209 in the wireless communication device 409. On the other hand, the temperature of the casing excluding the vicinity of the antenna 200 in the wireless communication apparatus 400 is lower than the temperature of the casing excluding the vicinity of the antenna 209 in the wireless communication apparatus 409.

  FIG. 6 is a table showing simulation results of temperatures on the housing surface and the like of the wireless communication device 400 according to the first embodiment of the present invention and the wireless communication device 409 to be compared.

  As shown in FIG. 6, the surface temperature of the processor 310 in the wireless communication device 400 is 3.6 degrees C lower than the surface temperature of the processor 310 in the wireless communication device 409. In addition, the temperature of the top and bottom surfaces of the housing in the wireless communication device 400 is 2.7 degrees C lower than the temperature of the top and bottom surfaces of the housing in the wireless communication device 409. Further, the temperature of the lower bottom surface of the housing in the wireless communication device 400 is 0.9 degrees C lower than the temperature of the lower bottom surface of the housing in the wireless communication device 409.

  As described above, in the wireless communication device 400 according to the present embodiment, the heat sink 100 has the plate portion 150 facing the surface formed by the ground pattern 330 adjacent to the antenna 200 on the surface side of the circuit board 300. That is, the heat sink 100 in the present embodiment has a larger amount of heat radiated from the heat sink than the case where the plate portion 150 is not provided. That is, the temperature in the high temperature part of the wireless communication device 400 is further lowered. Therefore, the wireless communication device 400 according to the present embodiment has an effect that the heat radiation from the heat source included in the wireless communication device 400 can be made efficient.

  FIG. 7 is a perspective view showing an example of the configuration of the heat sink included in the modification of the wireless communication device according to the first embodiment of the present invention.

  In the heat sink 101 in this modification, the side surface portion 131 extends to the side of the antenna 200, and the surface area is increased. That is, the heat sink 101 has a larger amount of heat radiated from the heat sink than the heat sink 100. That is, the temperature in the high temperature part of the wireless communication device 400 is lower than when the heat sink 100 is used. Therefore, the heat sink 101 in the present modification has an effect that the heat dissipation efficiency from the heat source included in the wireless communication device is higher than that of the heat sink 100.

In the above description, the case where the antenna 200 is a pattern antenna has been described. However, the antenna 200 in the present embodiment has the same effect as when the antenna 200 is a pattern antenna even if the antenna 200 is a chip antenna.
(Second Embodiment)
Next, a second embodiment of the present invention based on the first embodiment of the present invention will be described. In this embodiment, the heat sink radiates heat to the ground pattern on the back side of the circuit board.

  A configuration in the present embodiment will be described.

  FIG. 8 is a two-view diagram illustrating an example of the configuration of the wireless communication device according to the second embodiment of the present invention. More specifically, the upper diagram is a top view of the components present on the lower surface of the circuit board included in the wireless communication device as seen transparently from above. Further, the lower drawing is a side view of the components included in the wireless communication device as seen transparently from the side.

  The wireless communication device 405 in the present embodiment includes a circuit board 305 and a heat sink 105.

  The circuit board 305 includes an antenna 200, a ground pattern 330, a ground pattern 335, and a heat source.

  The ground pattern 335 is formed on the lower surface side of the circuit board 305 in a region adjacent to the antenna 200 on both sides of the antenna 200 and inside the substrate and extending to the vicinity of the power supply IC 320.

  The heat sink 105 dissipates the heat conducted from the heat source to the ground pattern 335 as well. That is, the heat sink 105 is thermally connected to the heat source and the ground pattern 335. A heat conductive sheet 110 may be inserted between the heat sink 105 and the heat source and ground pattern 335. The heat sink 105 may be thermally connected to another ground pattern or a casing.

  FIG. 9 is a perspective view showing an example of the configuration of the heat sink 105 included in the wireless communication device 405 according to the second embodiment of the present invention. More specifically, FIG. 9 is a perspective view of the heat sink 105 as viewed obliquely from below.

  When the heat sink 105 is installed on the circuit board 305, it is parallel to the circuit board 305 at a part of the position on the lower surface side of the circuit board 305 facing the surface formed by the ground pattern 335 adjacent to both sides of the antenna 200. It has a spring plate part 135 installed. The spring plate part 135 is in contact with the ground pattern 335 by elastic force and is thermally connected to the ground pattern 335. On the lower surface side of the heat sink 105, there is no plate portion at a position facing the surface formed by the antenna 200.

  Other configurations in the present embodiment are the same as those in the first embodiment.

  As described above, in the wireless communication apparatus 405 in the present embodiment, the heat sink 105 has the plate part 150 and the notch part 190 on the surface side of the circuit board 305. The heat sink 105 radiates heat to the ground pattern 335 adjacent to the antenna 200 on the back side of the circuit board 305. In the heat sink 105 in the present embodiment, since the spring plate portion 135 is in contact with the ground pattern 335, the amount of heat that can be radiated from the heat sink is larger than that in the heat sink 100 of the first embodiment. That is, the temperature in the high temperature part of the wireless communication device 405 is lower than the temperature in the high temperature part of the wireless communication device 400. Therefore, the heat sink 105 in this embodiment has an effect that the heat dissipation efficiency from the heat source included in the wireless communication device is higher.

  The present invention has been exemplarily described with the above-described embodiments and modifications thereof. However, the technical scope of the present invention is not limited to the scope described in the above-described embodiments and modifications thereof. It will be apparent to those skilled in the art that various modifications and improvements can be made to such embodiments. In such a case, new embodiments to which such changes or improvements are added can also be included in the technical scope of the present invention. This is clear from the matters described in the claims.

  INDUSTRIAL APPLICABILITY The present invention can be used in applications that improve the efficiency of heat dissipation in wireless communication devices such as mobile phones, smartphones, tablet terminals, notebook PCs, televisions, and cameras that have a wireless communication function.

100, 101, 105, 109 Heat sink 110 Thermal conductive sheet 120, 129 Plate portion 130, 131, 139 Side surface portion 135 Spring plate portion 140 Plate portion 150 Plate portion 190 Notch portion 200, 209 Antenna 300, 305, 309 Circuit board 310 Processor 320 Power IC
330, 335 Ground pattern 360 Side 400, 405, 409 Wireless communication apparatus

Claims (10)

  A heat sink provided on a circuit board on which an antenna and a ground pattern adjacent to each other except one direction are formed around a surface formed by the antenna, which is used to operate the antenna with predetermined characteristics, A heat sink which is thermally connected to an upper heat source and which faces at least a part of the surface formed by the ground pattern.   The heat sink according to claim 1, wherein a surface formed by the antenna and a surface forming the heat sink are not opposed to each other.   The heat sink according to claim 1, wherein the ground pattern is adjacent to both sides of the antenna and the inside of the substrate.   The heat sink as described in any one of Claim 1 to 3 which provided the member which contacts the said ground pattern.   The heat sink according to claim 4, wherein the member is a spring plate provided at a location facing a surface formed by the ground pattern. The heat sink according to any one of claims 1 to 5, wherein the antenna forms a split ring resonator. An antenna,
A ground pattern adjacent to the surface formed by the antenna except for one direction, which is used to operate the antenna in a predetermined characteristic;
A heat source,
A circuit board comprising: a heat sink which is thermally connected to the heat source and which faces at least a part of the surface formed by the ground pattern. The circuit board according to claim 7, wherein a surface formed by the antenna and a surface forming the heat sink are not opposed to each other. An antenna,
A ground pattern adjacent to the surface formed by the antenna except for one direction, which is used to operate the antenna in a predetermined characteristic;
A heat source,
A wireless communication apparatus comprising: a heat sink that is thermally connected to the heat source and that faces at least a part of the surface formed by the ground pattern. The wireless communication device according to claim 9, wherein a surface formed by the antenna and a surface forming the heat sink are not opposed to each other.

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