JP2001267772A - Heat dissipation structure of electronic components - Google Patents

Abstract

(57) [Problem] To provide a heat dissipation structure for an electronic component with an improved heat dissipation effect. A high-frequency power amplifier is housed in a housing, and the housing is joined to a heat radiating member via a meandering thin-tube heat pipe. The housing 16 may generate a gap C due to thermal distortion during cutting, but due to deformation of the heat pipe 20 due to compression during mounting, the heat pipe 20
Changes to a shape following the shape of the gap C, the gap C is eliminated, and the heat pipe 20 is in close contact with the warped groove 16d over the entire surface in the Y direction. The soft plating 22 coated on the outer surface of the heat pipe 20 is softened and deformed by pressure bonding and flows, thereby closing the gap C more reliably.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat dissipation structure for electronic components.

[0002]

2. Description of the Related Art In recent years, digitalization, broadband, and large capacity of electronic devices such as information devices, mobile communication devices, and broadcast devices have been developed. Along with this, it is required to mount a large number of semiconductor elements also in a high power signal portion in order to respond to demands for higher integration of circuits of electronic components used in these electronic devices and lower distortion of signal amplifiers. . In this case, downsizing of the electronic device is inevitable, and therefore, it is necessary to efficiently remove the heat generated from the semiconductor element by using a small radiator.

[0003] In particular, in the information society in the future, further expansion of the use of mobile communication (CDMA) is expected. In this case, the power amplification section of the base station is required to reduce signal linearity and reduce distortion. Power efficiency is very poor because it is used in areas with large backoffs. For this reason, the amount of heat generated from the power amplifying unit is so large as to be incomparable with the conventional one, and there is a greater need to provide an efficient heat dissipation structure.

As a heat radiating structure for these electronic components, a finned heat radiating member made of a material having good thermal conductivity is usually provided in close contact with the electronic components.

For example, in the case of the high-frequency power amplifier 9 used as the power amplifier of the above-described base station, as an example,
It is configured as shown in FIGS.

A high-frequency signal input from the coaxial connector 8a receives a semiconductor element (F) via an impedance conversion circuit, a bias circuit and the like (not shown) mounted on the circuit board 1a.
ET) 2a and amplified to a predetermined level. The amplified signal is branched by a distribution circuit (not shown) mounted on the circuit board 1b, and is divided into semiconductor elements (FETs) 2 respectively.
b, 2c and amplified to a predetermined level. The amplified signal is combined by a combining circuit (not shown) mounted on the circuit board 1c and transmitted to an antenna (not shown) via the coaxial connector 8b and a coaxial cable (not shown).

The high-frequency power amplifier 9 generates a large amount of heat in the last two semiconductor elements 2b and 2c during operation. Further, heat is also generated in the semiconductor element 2a which is the last driving stage, and these semiconductor elements 2a to 2a are generated.
c, the total amount of heat generated locally and concentrated is most of the total heat generation in the high-frequency power amplifier 9, for example, 9
Occupies about 0%.

In order to remove the generated heat, the circuit boards 1a to 1c on which the semiconductor elements 2a to 2c and the like are mounted are housed in a housing 3 made of a material such as an aluminum alloy having good thermal conductivity. You. In this case, since the three circuit boards 1a to 1c are arranged in a plane, the housing 3
Are formed in a box shape having a large area of the bottom surface 3a. The housing 3 is provided with a heat conductive member, for example, a silicon compound 4 applied to the outside of the bottom surface 3a, and a heat radiating member 5 provided with a large number of fins 5a. And the semiconductor element 2
The heat generated from a to 2c and the like is radiated from the heat radiation member 5 through the housing 3.

[0009]

However, in the case of the conventional high-frequency power amplifier 9 described above, the heat generated from the semiconductor elements 2a to 2c having a relatively narrow plane is mainly due to the relatively large plane. After being thermally conducted (heat-diffused) to the entire case 3 having the above, heat is transferred to the heat radiating member 5 at each part of the plane of the case 3, and the remaining heat is transmitted to each part of the plane of the case 3. After the heat is directly transmitted to the heat dissipating member 5, the heat dissipating (heat diffusing) is performed on the entire heat dissipating member 5 having a relatively large flat surface. Heat is dissipated through. Therefore, heat conduction (heat diffusion) inside the casing 3 or the heat radiating member 5 having a relatively large flat surface is not sufficiently performed, and there is a problem that the performance of the heat radiating member 5 is not sufficiently brought out.

In addition, the above-mentioned conventional high-frequency power amplifier 9
In the case of, the casing 3 is formed into a box shape by cutting a thick plate material made of an aluminum alloy, and a concave portion 3b for accommodating the circuit boards 1a to 1c is formed therein. During cutting, thermal stress remains due to the difference in cooling rate between the inner surface and the outer surface of the thick plate material, and after the processing, when the thermal stress is released, the outer surface contracts and warps,
There may be a gap C between the bottom surface 3a of the housing 3 and the top surface of the heat radiating member 5 (see FIG. 4). This gap C becomes a contact heat resistance (a heat transfer resistance existing at a contact portion between members),
Further inhibits the heat dissipation effect.

The present invention has been made in view of the above problems, and has as its object to provide a heat dissipation structure for an electronic component having an improved heat dissipation effect.

[0012]

According to the present invention, there is provided a heat radiating structure for an electronic component, wherein the electronic component is housed in a housing having at least one surface made of a good heat conductive material, and a heat radiating member is provided outside the one surface. In the heat radiating structure of the electronic component that radiates heat generated from the electronic component from the heat radiating member through the housing, a heat pipe including a meandering thin tube is provided between the housing and the heat radiating member. The heat pipe is crimped between the housing and the heat radiating member and is deformed flat (the invention according to claim 1).

Accordingly, when heat generated from a heat source such as a semiconductor element having a narrow flat surface of the electronic component is diffused on the flat surface of the housing, and the heat distribution on the flat surface is biased,
By providing a heat pipe consisting of a meandering thin tube between the housing and the heat dissipating member, the work medium of the heat pipe flows with the bias of the heat distribution as a driving source, and the heat is uniformly and efficiently diffused throughout the heat pipe. Therefore, heat is uniformly and efficiently transmitted to each part on the plane of the heat radiating member via the heat pipe, and the function of the heat radiating member can be sufficiently exhibited to obtain a good heat radiating effect. In addition, since the heat pipe closely follows the shape of the gap between the housing and the heat dissipating member, the contact heat resistance portion that was present as a gap between the members is eliminated, and the heat transfer is further improved. Is achieved.

In this case, the heat pipe composed of the meandering thin tube is mainly composed of a turn portion and a straight tube portion, and the turn portion is formed to have a smaller diameter than the straight tube portion.
Invention), the distance between adjacent straight pipe portions via the turn portion can be reduced while securing a predetermined radius of curvature necessary for preventing deformation and the like of the turn portion. The straight pipe portions are surely in close contact with each other and are aligned, the contact heat resistance portion is eliminated, and a better heat transfer effect can be obtained.

[0015] In this case, the heat pipe formed of the meandering thin tube is provided wider than an electronic component accommodating portion of the housing formed to house the electronic component. When the expansion portion is further formed corresponding to the wide portion of the heat pipe (the invention according to claim 5),
More preferred. Here, the term “wide” refers to both the case where the width is wide in two opposing directions and the case where the width is wide in all four directions.

Further, in this case, a spacer member is provided between the housing and the heat radiating member for adjusting a deformation amount of the heat pipe formed of the meandering thin tube by crimping (the invention according to claim 6). ), The amount of deformation of the heat pipe can be adjusted to a desired value, which is preferable. Further, when assembling the housing to the heat radiating member, there is no possibility that the meandering thin tube heat pipe is crushed by mistake, for example, by excessively tightening the fastening member. Here, the spacer member may be provided as a member that is exceptionally independent of the housing or the like, or may be provided as a part of the housing or the like.

Further, in the heat dissipation structure for an electronic component according to the present invention, instead of the heat pipe comprising the meandering thin tube,
A plurality of heat pipes may be provided in parallel (the invention according to claim 2).

In the heat radiating structure for an electronic component according to the present invention, at least a part of the heat pipe is previously coated with a soft solder before being attached between the housing and the heat radiating member. The invention according to claim 3),
When the heat pipe is pressed between the housing and the heat dissipating member, the soft solder is softened and deformed and flows, and the gap as the contact heat resistance portion is more reliably eliminated, and the heat soldering member is disposed between the housing and the heat dissipating member. A good heat transfer effect can be obtained.
Here, the soft solder refers to a solder metal having a softening point in the range of 93 to 183 ° C.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of a heat dissipation structure for an electronic component according to the present invention (hereinafter, referred to as an embodiment).
This will be described below with reference to the drawings, taking the high-frequency power amplifier described in the conventional example as an example of an electronic component.
Note that, for the same components as those in the conventional example, duplicate description may be omitted.

FIG. 5 is a plan view of the high-frequency power amplifier, FIG. 6 is a cross-sectional view of the high-frequency power amplifier, FIG. 7 is a right side view of the high-frequency power amplifier, and FIG. This will be described with reference to a plan view of the meandering thin tube heat pipe.

The high frequency power amplifier 10 includes a circuit board 12a
To 12c, semiconductor elements (FETs) 14a to 14c, and circuits (not shown) mounted on the circuit boards 12a to 12c.
It is connected to the coaxial connector 11a and the like (see FIG. 5). As described in the conventional example, in the high-frequency power amplifier 10, during operation, the semiconductor elements 14a to 14c are main heat sources.

As the heat dissipation structure, as in the conventional example, the housing 1
6 and a heat dissipating member 18 are provided.
A heat pipe (heat transfer cushion plate: hereinafter simply referred to as a heat pipe) 20 composed of a meandering thin tube is provided between the housing 16 and the heat radiation member 18.

The housing 16 has a recess 16 a as an electronic component housing for housing the high-frequency power amplifier 10, which is formed in accordance with the shape of the high-frequency power amplifier 10. A plurality of projecting portions 16b are formed in a part of the concave portion 16a, and the projecting portions 16b are in close contact with the semiconductor elements 14a to 14c,
6 (Z1 direction) above the circuit boards 12a to 12c.
Adhesion between the semiconductor elements 14a to 14c arranged in a floating state and the housing 16 is ensured. Further, unlike the conventional example, wide portions (extended portions) 16h having a width ΔW are provided on both sides in the Y direction in FIG. Then, the housing 16
A groove 16d having a width W2 larger than the width W1 of the concave portion 16a is formed outside the bottom surface (bottom portion) 16c, that is, on the side opposite to the side where the concave portion 16a is formed (see FIGS. 6 and 7). . In FIG. 6, reference numeral 17 denotes the circuit board 1.
3 shows a lid of a housing 16 for closing 2a to 12c and semiconductor elements 14a to 14c.

The housing 16 configured as described above is made of, for example, a thick plate material (material) made of a material having good thermal conductivity such as an aluminum alloy, and is formed by cutting.
a and a groove 16d are provided, and are formed in a substantially box shape.

The heat dissipating member 18 is provided with a large number of fins 18a in the same manner as described in the conventional example, and is formed using an aluminum material in this case (see FIG. 7).

The heat pipe 20 has 16 straight pipe sections (cushion heat transfer pipe sections) 20a and adjacent straight pipe sections 20a,
20b, a curved tubular turn (bend) connecting 20a
These end portions E1 and E2 are connected by a header portion 20c to form a circulation line (see FIG. 8). The header portion 20c is provided with an introduction port 20d for introducing a working medium into the heat pipe 20. As described above, the wide portion 16h is attached to the housing 16.
Is provided, the width W2 of the groove 16e is formed large, so that the heat pipe 20 housed in the groove 16e is connected to the high-frequency power amplifier 10 as described later.
Regardless of the plane dimensions of FIG. 8, the one having a large width in the Y direction in FIG. 8 can be used, and the heat radiation efficiency can be improved. In this case, the width may be increased in the X direction instead of the Y direction or together with the Y direction.

As a working medium of the heat pipe 20, for example, water is used. In this case, the pressure is reduced to maintain the gas-liquid mixed state in the sealed state. Therefore, liquid water (liquid working medium) in contact with the high-temperature side is vaporized by receiving heat, while water vapor (gaseous working medium) in contact with the low-temperature side is liquefied by releasing heat. And
Heat is transmitted between the upper and lower portions (Z direction) of the heat pipe 20 in FIG. At this time, if there is a bias in the heat distribution on the high temperature side plane of the heat pipe 20, this bias in the heat distribution becomes a driving source, for example, water located at the high temperature point vaporizes and moves to the low temperature point side. 8 (for example, flows in the direction of the arrow in FIG. 8), and the heat is uniformly and rapidly diffused over the entire surface of the heat pipe 20 in the X and Y directions in FIG. When the heat distribution on the flat surface on the high temperature side of the heat pipe 20 is uniform, that is, when the temperature is made uniform at each part of the flat surface, the flow of water on the flat surface stops. Then, heat is uniformly and efficiently released from each part of the entire surface of the heat pipe 20. In addition, in FIG. 8, for convenience of explanation, water is schematically (pictorially) shown to flow in one direction of the arrow and circulate in the heat pipe 20. It flows in both directions at each part. However, in this case, if the end of the heat pipe is closed, the flow of water near the end becomes insufficient, so that the circulation structure as described above is preferable.

The heat pipe 20 constructed as described above
Has good thermal conductivity and excellent extensibility, for example,
For example, using a pipe made of aluminum and having a diameter of about 1 to 2 mmφ, the adjacent straight pipe portions 20a are formed so as to be aligned. At this time, turn part 20
b is formed by processing and bending the diameter to about 0.5 to 1.0 mmφ so that the adjacent straight pipe portions 20a and 20a are closely aligned. In addition,
The thickness of the heat pipe 20 is, for example, about 0.1 mm.

A housing 16 accommodating the high-frequency power amplifier 10
A method of attaching the heat pipe 20 and the heat radiating member 18 to the above will be described below.

When the heat pipe 20 is attached, the outer surface of the straight pipe portion 20a has a softening point of, for example, 117 ° C.
Is covered with a soft solder 22 such as an In-Sn based solder, and a soft solder 22 is provided between adjacent straight pipe portions 20a, 20a.
It is joined by. Here, the soft solder 22 is made of In-
The softening point is not limited to the Sn type and any other material having a softening point in the range of 93 to 183 ° C can be suitably used.

Then, the meandering thin tube heat pipe is positioned and arranged at a predetermined position on the upper surface of the heat dissipating member 18 with the heat dissipating member 18 disposed in advance (see FIG. 8). Next, the housing 16 is positioned and arranged so that the heat pipe 20 is accommodated in the groove 16 d of the housing 16. Finally, the housing 16 and the heat radiating member 18 are fixed with the heat pipe 20 sandwiched therebetween by a method such as bolting (see FIGS. 6 and 7).

At this time, the side wall 16e of the groove 16d functions as a spacer member. That is, the height H of the side wall 16e is formed smaller than the original dimension D1 of the diameter D of the heat pipe 20. Therefore, when the housing 16 and the heat radiation member 20 are fixed, the heat pipe 20 is crimped. Then, it deforms flat so that the diameter D becomes the same dimension as the height H. Therefore, by appropriately changing the height H of the side wall 16e, the amount of change in the diameter D of the heat pipe 20 can be easily adjusted to a desired value. Further, when the housing 16 and the heat radiating member 20 are fixed by a method such as bolting, there is no possibility that the heat pipe 20 is crushed due to excessive tightening by mistake.

As described in the conventional example, the center of the bottom surface 16 of the housing 16 in the width direction (Y direction in FIG. 9) is upward (Z1 direction) as shown in FIG. Contrary to the above, a gap C may be generated between the bottom surface and the upper surface of the heat radiating member.
The shape of the heat pipe 20 changes to follow the shape of the gap C, and the gap C is eliminated. That is, the heat pipe 20
In FIG. 9, the straight pipe portions 20a-1 at both ends in the Y direction have a diameter D greatly reduced as compared with the original dimension D1, while the straight pipe portions 20a-2 at the center portion in the Y direction are, for example, Since the diameter D hardly deforms to the same extent as the original dimension D1, the heat pipe 20 is in close contact with the warped groove 16d over the entire surface in the Y direction. At this time, the soft plating 22 coated on the outer surface of the heat pipe 20 is softened and deformed by pressure bonding and flows, thereby closing the gap C more reliably. As a result, the gap C, which has been the contact thermal resistance, is eliminated, and the housing 16, the heat pipe 20, and the heat radiating member 18 are tightly integrated.

According to the heat dissipation structure of the high-frequency power amplifier 10 according to the present embodiment configured as described above, when the high-frequency power amplifier 10 is used, the heat is intensively generated from the semiconductor elements 14a to 14c having a narrow plane. The heat that is generated is
6b, the light is transmitted to the housing 16 and diffuses into a wide flat surface of the housing 16. At this time, heat diffusion is insufficient and the
In the process in which the unevenness of the heat distribution is generated in the plane of the heat pipe, the water in the heat pipe 20 flows by changing the layer and the density by using the unevenness of the heat distribution as a driving source, and the heat is efficiently transmitted to the entire surface of the heat pipe 20. Is done.

The heat transmitted from the housing 16 to the heat pipe 20 is uniformly and efficiently transmitted to the entire surface of the heat radiating member 18 at each portion on the entire surface of the heat pipe 20. Then, heat is efficiently radiated from the fins 18 a provided on the entire surface of the heat radiating member 18, and the temperature rise of the high-frequency power amplifier 10 is suppressed.

The above-mentioned effects can be obtained by arranging a plurality of heat pipes in parallel, instead of the heat pipes 20 composed of the meandering thin tubes of the embodiment described above.

[0037]

According to the heat dissipating structure for an electronic component of the present invention, a heat pipe made of a meandering thin tube is provided between the heat dissipating member and the housing for accommodating the electronic component. It is crimped between the heat dissipating members and deforms flat,
According to the heat radiating structure for an electronic component according to the second aspect, since a plurality of heat pipes are provided in parallel instead of the heat pipe formed of the meandering thin tube, each of the heat radiating members on the plane of the heat radiating member is provided via the heat pipe. The heat is uniformly and efficiently transmitted to the parts, and the gap between the members is eliminated so that the heat can be transmitted well, and the function of the heat radiating member is sufficiently exhibited to obtain a good heat radiating effect. Can be.

According to the heat radiating structure for an electronic component of the present invention, at least a part of the heat pipe is coated with the soft solder before the heat pipe is mounted between the housing and the heat radiating member. The gap as the contact heat resistance portion is further eliminated, and a better heat transfer effect can be obtained between the housing and the heat radiating member.

Further, according to the heat radiation structure of the electronic component according to the fourth aspect, since the heat pipe formed of the meandering thin tube has the turn portion formed to have a smaller diameter than the straight tube portion, the straight tube portions are more reliably connected to each other. , The contact heat resistance portion is eliminated, and a better heat transfer effect can be obtained.

According to the fifth aspect of the present invention, the heat pipe made of the meandering thin tube is provided wider than the electronic component accommodating portion of the housing, and the housing is made wider than the width of the meandering thin tube heat pipe. This is more preferable because an extended portion is further formed corresponding to the portion.

According to the heat radiating structure for an electronic component of the present invention, a spacer member is provided between the housing and the heat radiating member for adjusting the amount of deformation of the heat pipe formed of the meandering thin tube by crimping. Therefore, the amount of deformation can be adjusted to a desired value, and there is no possibility of crushing the heat pipe, which is preferable.

[Brief description of the drawings]

FIG. 1 is a plan view of a high-frequency power amplifier and the like for describing a heat radiation structure of a conventional high-frequency power amplifier.

FIG. 2 is a cross-sectional view of a high-frequency power amplifier and the like taken along line II-II in FIG. 1 for explaining a heat radiation structure of the conventional high-frequency power amplifier.

FIG. 3 is a right side view of a high-frequency power amplifier and the like for describing a heat radiation structure of a conventional high-frequency power amplifier.

FIG. 4 is a cross-sectional view of a high-frequency power amplifier and the like on a line IV-IV in FIG. 1 for explaining a warped state of a housing in a heat radiation structure of a conventional high-frequency power amplifier.

FIG. 5 is a plan view of a high-frequency power amplifier and the like for describing a heat radiation structure of the high-frequency power amplifier according to the present embodiment.

FIG. 6 is a cross-sectional view of the high-frequency power amplifier and the like taken along line VI-VI in FIG. 5 for explaining a heat radiation structure of the high-frequency power amplifier according to the present embodiment.

FIG. 7 is a right side view of the high-frequency power amplifier and the like for describing a heat radiation structure of the high-frequency power amplifier according to the present embodiment.

FIG. 8 is a view for explaining a meandering thin-tube heat pipe in the heat dissipation structure of the high-frequency power amplifier according to the embodiment;
It is a top view of a meandering thin tube heat pipe.

FIG. 9 is a cross-sectional view of the high-frequency power amplifier and the like taken along line IX-IX in FIG. 5 for explaining a warped state of the housing in the heat dissipation structure of the high-frequency power amplifier according to the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 High frequency power amplifier 12a-12c Circuit board 14a-14c Semiconductor element 16 Housing 16e Spacer member 16h Wide part 18 Heat dissipation member 20 Heat pipe 20a Straight pipe part 20b Turn part

Claims (6)

[Claims] An electronic component is housed in a housing whose at least one surface is made of a material having good thermal conductivity, a heat radiating member is provided outside the one surface, and heat generated from the electronic component is transmitted through the housing through the housing. In the heat radiating structure of an electronic component that radiates heat from a heat radiating member, a heat pipe formed of a meandering thin tube is provided between the case and the heat radiating member, and the heat pipe is press-bonded between the case and the heat radiating member. A heat dissipating structure for an electronic component, wherein the heat dissipating structure is flattened and deformed. 2. An electronic component is housed in a housing whose at least one surface is made of a material having good thermal conductivity, a heat radiation member is provided outside the one surface, and heat generated from the electronic component is passed through the housing. In the heat radiating structure of the electronic component that radiates heat from the heat radiating member, a plurality of heat pipes are provided in parallel between the housing and the heat radiating member, and the heat pipe is press-bonded between the housing and the heat radiating member. A heat dissipating structure for an electronic component, wherein the heat dissipating structure is flattened and deformed. 3. The heat pipe according to claim 1, wherein at least a part of the heat pipe is coated with a soft solder before being attached between the housing and the heat radiating member. Heat dissipation structure for electronic components. 4. The heat pipe comprising the meandering thin tube,
2. The heat radiating structure for an electronic component according to claim 1, wherein the heat radiating structure is mainly composed of a turn portion and a straight tube portion, and the turn portion has a smaller diameter than the straight tube portion. 5. The heat pipe comprising the meandering thin tube,
The casing is formed wider than the electronic component accommodating portion of the casing formed to accommodate the electronic component, and the casing further forms an extension corresponding to a wide portion of the meandering thin tube heat pipe. 2. The heat radiating structure for an electronic component according to claim 1, wherein: 6. The electronic device according to claim 1, wherein a spacer member is provided between the housing and the heat radiating member to adjust a deformation amount of the heat pipe made of the meandering thin tube by crimping. Heat dissipation structure of parts.