JP2009099753A - Heat sink - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat sink whose production is easy at low-cost and has high production efficiency, the heat sink excelling in heat liberation and decreasing electromagnetic noise release. <P>SOLUTION: The heat sink has: two or more heat radiating fins 2a to 2h that are individually prepared by processing metal plates; a heat transmission substrate 3 that comes in contact with a heating element 6; and adhesion layers 5a to 5d set between the heat radiating fins and heat transmission substrate to join them with an adhesive, wherein the adhesion layers are electrically insulating and highly thermally conductive. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a heat sink that is a heat radiating body for dissipating heat generated from electric parts such as various electronic devices, and more particularly to a heat sink in which a heat radiating fin and a heat transfer substrate are separated.

  In recent years, various electronic components have become increasingly denser and smaller in size, and the amount of heat generated per unit area generated from these electronic components has increased. Heat sinks that dissipate the heat are also becoming more sophisticated. Is now required. In addition, electrical components that are becoming smaller and lighter are required to have better performance and lighter weight. As such a heat sink, there is a heat sink by a metal extrusion technique. However, it is difficult to manufacture a large heat sink, and it is difficult to manufacture fins having a complicated structure. Also, thin fins are difficult to extrude, and it is difficult to deal with electrical parts that are becoming lighter. Furthermore, the extrusion method heat sink has a high die and is difficult to apply to various types of electrical products.

  Further, heat sinks made of corrugated fins manufactured by bending metal thin plates are also employed (Japanese Patent Laid-Open Nos. 8-130274 and 8-320194). Since the corrugated fin has a hermetically sealed portion at the upper part (on the opposite side when the heat transfer substrate side is the bottom plate), the air heated by the fin is not easily removed and the heat dissipation is not good. Further, since the corrugated fin has a constant shape, there is a problem that the area of the joint surface with the heat transfer substrate cannot be freely taken.

  A heat radiating fin having a U-shaped heat radiating fin is also known (Japanese Patent Application No. 10-126075). In this case, a large number of U-shaped fins are stacked, and heat transfer resistance is generated in each overlapped portion, so heat transfer efficiency is not good. A fin having a structure in which a thin plate is punched into a U-shape is also known as a heat radiating fin (Japanese Patent Laid-Open No. 2003-174129). Therefore, the heat transfer efficiency is poor.

On the other hand, when electromagnetic noise generated inside the electronic component propagates to the heat sink, there is a problem that the heat sink functions as an antenna and emits electromagnetic noise to the outside. In particular, the generation of electromagnetic noise tends to increase as the operating frequency of LSIs and memories that are electronic components increases. And electromagnetic noise causes interference not only in other electronic devices but also in its own electronic devices, and is susceptible to failures such as malfunctions.
For this reason, techniques for interposing a sheet that absorbs electromagnetic noise between the electronic component and the heat sink have been developed (Japanese Patent Application Laid-Open No. 2004-22738, Japanese Patent Application Laid-Open No. 2006-310812). In addition, a technique for Faraday shielding electromagnetic radiation from a microprocessor using a heat sink connected to a ground plane has been reported (Japanese Patent Laid-Open No. 11-260976).
Furthermore, a heat sink device is disclosed in which a high heat-conducting radiating fin and a high-resistance radiating fin are mixed on a base portion in contact with a high heat generating element (Japanese Patent Laid-Open No. 2002-305273). According to this apparatus, since the intensity of electromagnetic noise is proportional to the current, the radiated electromagnetic field level at the high-resistance radiating fin is lowered, and the antenna efficiency is lowered as a whole.

JP-A-8-320194 (page 1-2, FIG. 1). JP-A-8-130274 (page 1-2, FIG. 1). Japanese Patent Laid-Open No. 10-126075 (page 1-2, FIG. 1). Japanese Patent Laying-Open No. 2003-174129 (page 1-2, FIG. 1). JP 2004-22738 A JP 2006-310812 A JP-A-11-260976 JP 2002-305273 A

  However, in the case of the techniques described in Patent Documents 5 to 7, since the fins and the base portion of the heat sink are integrally formed, there are problems in manufacturing as described above. Also, in the case of the technique described in Patent Document 8, since the high heat-transfer radiating fin is integrally formed with the base portion, there is a problem in manufacturing as described above, and the high-resistance radiating fin is replaced with the high heat-transfer radiating fin. It must be manufactured from another material, further reducing productivity.

  An object of the present invention is to provide a heat sink that is simple to manufacture, low in cost, high in production efficiency, excellent in heat dissipation, and reduced in emission of electromagnetic noise.

The present invention has been made to achieve the above object, and the heat sink of the present invention has the following characteristics. The present invention provides a plurality of heat dissipating fins each individually processing a metal plate, a heat transfer substrate in contact with a heating element, and an adhesive that is interposed between the heat dissipating fins and the heat transfer substrate to bond them together. And a heat sink.
In the present invention, the adhesive layer is preferably electrically insulating and highly thermally conductive.
In the present invention, the adhesive layer is preferably electrically insulating and radio wave absorbing.

  The present invention provides a heat sink with good heat dissipation. A heat sink, also called a heat sink or radiator, is a component that is attached to a machine or electrical component that generates heat, and is intended to lower the temperature of the heating element by radiating heat. It has the structure where the fin which is a body is attached to the heat-transfer board | substrate.

  The heat transfer substrate is a metal plate that serves to transfer heat of the heating element to the fins while being bonded to the heat radiating fins to fix the fins. The heat transfer substrate does not necessarily have to be a flat surface, and can take a curved surface or other shapes along the structure of the surface of the heating element. The material of the heat transfer substrate is preferably made of a metal having good heat transfer properties such as aluminum or an alloy thereof, copper or an alloy thereof.

  The heating element is an electrical component that generates heat when used, such as a semiconductor element such as a CPU or LED, or a lamp such as a halogen lamp, and the heat sink of the present invention generates heat by dissipating the heat of these heating elements by the radiation fins. The purpose is to suppress the temperature rise of the body.

The heat dissipating fins of the present invention are characterized by individually processing metal plates. If it does in this way, even if a radiating fin is complicated shape, processing will be easy, manufacture will become simple and low cost. In the present invention, since the heat radiation fin and the heat transfer substrate are bonded and fixed via an adhesive layer, the heat radiation fin can be easily attached, and the degree of freedom of the position of the heat radiation fin is high and the production is simple. In addition, a heat sink with good heat dissipation can be obtained.
When the adhesive layer is electrically insulating, the heat transfer substrate and the heat radiating fin are electrically separated. Therefore, even if electromagnetic noise generated in the electronic component (heating element) is transmitted to the heat transfer board, the noise is not transmitted to the heat radiation fins thereon, and the heat sink does not function as an antenna. In this case, even if the electromagnetic noise absorbing layer is not prepared separately from the heat sink as in the prior art, the productivity can be increased by using the adhesive layer used for adhering the radiating fin also as the electromagnetic noise absorbing layer (or blocking layer). In addition, since an extra electromagnetic noise absorbing layer is not interposed between the heating element and the heat transfer substrate, heat transfer from the heating element to the heat sink is improved. Further, when the adhesive layer has high thermal conductivity, heat transfer from the heat transfer substrate to the heat radiating fins can be ensured.
In addition, when the adhesive layer is radio wave absorbing, the electromagnetic noise is absorbed by the adhesive layer, so even if the electromagnetic noise generated in the electronic component (heating element) is transmitted to the heat transfer board, it is transmitted to the heat radiating fins thereon. The antenna efficiency of the heat sink is reduced.

In the present invention, the radiating fin is a U-shaped fin formed by bending a single metal plate into a U-shape, or an L-shaped fin formed by bending a single metal plate into an L-shape. It is preferable that a bottom plate which is a closed portion of the U-shaped fin or a back side surface of the bottom plate of the L-shaped fin is bonded to the heat transfer substrate.
If it does in this way, while improving productivity, since an upper part is an open structure, it can be set as the structure where the escape of the air heated by the heated side wall is favorable.

  When the adhesive layer is electrically insulating and has high thermal conductivity, it is preferable that the thermal conductive filler and the resin binder are the main components. When the adhesive layer is electrically insulating and radio wave absorbing, it is preferable that the main component is ferrite powder, a thermally conductive filler, and a resin binder.

In any of the direction along one side of the heat transfer substrate and the direction along the side orthogonal to the one side, it is preferable that a plurality of the radiation fins are arranged apart from each other.
When the radiating fins extend continuously along one side of the heat transfer board or a side perpendicular thereto, the antenna length becomes longer and the resonance frequency of the electromagnetic noise becomes smaller. It becomes easy to receive. Therefore, if a plurality of radiating fins are arranged apart from each other, the antenna length of each radiating fin can be shortened, and the resonance frequency of electromagnetic noise can be shifted to the high frequency side to cause malfunction of electronic equipment. Can be reduced.
At this time, if the adhesive layer has electrical insulation, the radiating fins are electrically separated from each other. Therefore, it is not necessary to take another electrical insulation of the radiating fins by another method, and productivity is also improved. No damage.

  According to the present invention, it is possible to obtain a heat sink that is simple to manufacture, low in cost, high in production efficiency, excellent in heat dissipation, and reduced in emission of electromagnetic noise.

Hereinafter, the present invention will be described based on embodiments shown in the drawings. FIG. 1 is a perspective view showing an example of a heat sink manufactured by the present invention. The heat sink 1 has U-shaped fins 2 a, 2 b, 2 c, 2 d,... 2 h formed by bending a single metal thin plate into a U-shape, and the interval between the open portions of the side faces in a certain direction. Open and arranged in parallel. The heat transfer substrate 3 and the back side surface 8 of the bottom plate 4 of the fin closed portion are joined by the first adhesive layer 5. A heating element 6 is tightly bonded to the heat transfer substrate 3. In the present invention, a plurality of U-shaped fins 2a, 2b, 2c and 2d are arranged in parallel at intervals, and the side walls 7a-1, 7a-2, 7b-1 of these U-shaped fins are arranged. 7b-2, 7c-1, 7c-2, 7d-1, and 7d-2 are arranged in parallel.
More specifically, the U-shaped fins 2 a to 2 d are arranged side by side in the 3 s direction along the horizontal side of the heat transfer substrate 3 with the side walls separated from each other. In addition, in the 3t direction along the vertical side of the heat transfer substrate 3, U-shaped fins 2e to 2h are arranged in parallel with the U-shaped fins 2a to 2d in parallel with the U-shaped cross sections being separated from each other. . Accordingly, the side walls 7a-1, 7a-2, 7b-1, 7b-2, 7c-1, 7c-2, 7d-1, and 7d-2 of the plurality of U-shaped fins 2e to 2h are also arranged in parallel. ing.
The first adhesive layers 5a to 5d are formed in a stripe shape along the 3t direction of the heat transfer substrate 3, and the U-shaped fins 2a and 2e are separated on the first adhesive layer 5a as described above. Are arranged. Similarly, the corresponding two U-shaped fins are also spaced apart from each other in the first adhesive layers 5b to 5d.

  The bonding by the first adhesive layer 5 does not require a high temperature that can cause distortion of the heat transfer substrate, and does not apply excessive force to the heat transfer substrate and the heat radiating fins and does not distort the material. Even if is heated, it becomes a stable heat transfer substrate or heat radiation fin. Adhesive bonding can be performed by a method in which an adhesive layer made of an inorganic or organic material having adhesiveness is provided on the bonding surface, or a tape-like adhesive such as an adhesive tape.

In the first invention of the present invention, such a first adhesive layer is electrically insulating and has high thermal conductivity.
The first adhesive layer can be formed by blending an inorganic or organic adhesive serving as a binder and a heat conductive filler. As the organic adhesive layer, a heat conductive adhesive or a class of adhesives called heat transfer cement is used. As the main component of the organic adhesive, silicone-based, epoxy-based, acrylic-based, and urethane-based resins that can withstand high temperatures of 120 ° C. to 150 ° C. are preferably used. Carbon black, graphite, titanium oxide or the like may be added to adjust the dielectric constant of the adhesive layer, and various auxiliary agents may be added.

As the thermally conductive filler, ceramic powders such as boron nitride, aluminum nitride, silicon nitride, aluminum oxide, zinc oxide, silicon oxide, magnesium oxide, ferrite, and silicon carbide, which are electrically insulating materials, carbon black, graphite Carbon powder such as diamond, powder in a fibrous form, and the like can be used, and one or more of these may be appropriately added to the binder. The particle size of the heat conductive filler is not particularly limited, but it may be preferably about 5 to 30 μm.
When the particle size of the thermally conductive filler is less than 5 μm, the thermal conductivity tends to decrease. On the other hand, as the particle size of the thermally conductive filler increases, the thermal conductivity improves, but in order to improve the thermal conductivity of the entire adhesive layer, the layer is made thinner and the adhesive and the adherend (heat transfer substrate, heat dissipation) It is more effective to improve the adhesion to the fin). From such a point, when the particle size of the thermally conductive filler exceeds 30 μm, the thickness of the adhesive layer becomes thick, the adhesiveness is lowered, and the thermal conductivity of the entire layer may be deteriorated.

  In the present invention, no conductive filler is added to the adhesive layer in order to provide insulation to the adhesive layer. Examples of the conductive filler include metals having good thermal conductivity such as copper, nickel, silver, gold, and aluminum, and alloys thereof.

In the first invention of the present invention, the electric conductivity (volume resistivity) of the first adhesive layer can be preferably 1 × 10 ⁹ Ω · cm or more, more preferably 1 × 10 ¹⁵ Ω · cm. This can be done. If the electrical conductivity is less than 1 × 10 ⁹ Ω · cm, electromagnetic noise from the heat transfer substrate cannot be blocked, and electromagnetic noise may be transmitted to the heat radiating fins and emitted to the outside.
The thermal conductivity can be about 0.8 to 3.0 W / m · ° C. When the thermal conductivity is less than 0.8 W / m · ° C., heat from the heat transfer substrate is hardly transmitted to the heat radiating fins, and the heat radiating effect may be lowered. In order to produce a product having a thermal conductivity exceeding 3.0 W / m · ° C., it is necessary to increase the blending amount of the thermally conductive filler, but the amount of the binder in the adhesive layer decreases accordingly, The strength may decrease.
In addition, what is necessary is just to adjust the mixture ratio of a binder and a heat conductive filler so that the electrical conductivity and heat conductivity of a 1st contact bonding layer may become the said range.

The second invention of the present invention is the same as the first invention except that a second adhesive layer that is electrically insulating and has high magnetic permeability is used instead of the first adhesive layer. The second adhesive layer can be formed by blending an inorganic or organic adhesive serving as a binder and a soft magnetic filler. As the organic adhesive layer, the one used in the first invention can be used.
As the soft magnetic filler, powders of various soft magnetic (high magnetic permeability) materials can be used. In order to provide insulation to the second adhesive layer, a high magnetic permeability metal (alloy) having electrical conductivity is used. Do not use. These metals (alloys) include permalloy (Fe-Ni alloy), supermalloy (Fe-Ni-Mo alloy), sendust (Fe-Si-Al alloy), soft ferrite, alpalm (Fe-Al alloy), permin bar. (Ni-Cr-Fe alloy) and isopalm (Ni-Cu-Fe alloy).

  On the other hand, a ferrite powder, which is a soft magnetic material, mixed with a heat conductive filler and further mixed with a binder is excellent in insulating properties and exhibits high magnetic permeability. The particle size of the ferrite powder is not particularly limited, but may be about 1 to 30 μm. When the particle size of the ferrite powder is less than 1 μm, the radio wave absorption rate tends to decrease. On the other hand, when the particle size of the ferrite powder exceeds 30 μm, the same problem as when the particle size of the heat conductive filler exceeds 30 μm may occur.

The soft magnetic material ferrite (soft ferrite) temporarily becomes a magnet by an external magnetic field. For example, iron, nickel, cobalt, and zinc-based soft ferrite can be preferably used.
As the heat conductive filler, the heat conductive filler used in the first adhesive layer can be used, and the first adhesive layer is also characterized in that no conductive filler is added to the adhesive layer in order to provide insulation to the adhesive layer. It is the same.

In the second invention of the present invention, the electrical conductivity (volume resistivity) of the second adhesive layer is preferably 1 × 10 ⁹ Ω · cm or more, more preferably 1 × 10 ¹¹ Ω · cm or more. Can do. If the electrical conductivity is less than 1 × 10 ⁹ Ω · cm, electromagnetic noise from the heat transfer substrate cannot be blocked, and electromagnetic noise may be transmitted to the heat radiating fins and emitted to the outside.
Further, as the magnetic permeability of the second adhesive layer, the real part of the complex relative permeability in the frequency band of 100 MHz to 3 GHz is preferably 2 or more (more preferably 4 or more), and the imaginary part of the complex relative permeability is preferred. Can be 0.4 or more (more preferably 0.8 or more). If the real part of the complex relative permeability in the frequency band of 100 MHz to 3 GHz is less than 2 or the imaginary part of the complex relative permeability is less than 0.4, the action of attenuating electromagnetic waves due to the permeability loss is reduced, and the heat transfer substrate The electromagnetic noise from the air cannot be cut off, and the electromagnetic noise may be transmitted to the heat radiating fins and emitted to the outside.

The thermal conductivity of the second adhesive layer can be about 0.8 to 3.0 W / m · ° C., and the reason is the same as that of the first adhesive layer.
What is necessary is just to adjust the mixture ratio of a ferrite powder and a heat conductive filler so that the electrical conductivity and magnetic permeability of a contact bonding layer may become the said range.

The radiating fin 2 is a U-shaped fin formed by bending a single metal plate into a U-shape, or an L-shaped fin formed by bending a single metal plate into an L-shape. It is preferable that a bottom plate which is a closed portion of the L-shaped fin or a back side surface of the bottom plate of the L-shaped fin is bonded to the heat transfer substrate.
For example, in the embodiment of FIG. 1, the heat radiating fins are U-shaped fins. The U-shaped fin is a heat radiating fin having a structure in which a single metal plate is bent into a U-shape. In the heat sink according to the embodiment of the present invention, a plurality of U-shaped fins are arranged in parallel in a certain direction at intervals, and the heat transfer substrate and the back side surface of the bottom plate which is a closed portion of the fins are joined. Thus, by having a U-shaped shape, a fin can be easily manufactured from a thin plate structure, and a thin and lightweight fin can be manufactured. Furthermore, since the U-shaped fin has a wide bottom, a large bonding area with the heat transfer substrate can be obtained. Moreover, since the upper part is an open shape, the dissipating property of the air heated by the fins is improved.

In any of the direction along one side of the heat transfer substrate 3 and the direction along the side orthogonal to the one side, it is preferable that a plurality of heat radiation fins are arranged apart from each other.
When the radiating fins extend continuously along one side of the heat transfer board or a side perpendicular thereto, the antenna length becomes longer and the resonance frequency of the electromagnetic noise becomes smaller. It becomes easy to receive. Therefore, if a plurality of radiating fins are arranged apart from each other, the antenna length of each radiating fin can be shortened, and the resonance frequency of electromagnetic noise can be shifted to the high frequency side to cause malfunction of electronic equipment. Can be reduced.
For example, in the embodiment of FIG. 1, a plurality of U-shaped fins 2 a to 2 d are arranged side by side in the 3 s direction along the horizontal side of the heat transfer substrate 3 with the side walls separated from each other. In addition, in the 3t direction along the vertical side of the heat transfer substrate 3, two U-shaped fins 2a, 2e (or 2b, 2f, etc.) are arranged side by side with their U-shaped cross sections separated from each other. Here, when the sidewalls of the two U-shaped fins 2a, 2e (or 2b, 2f, etc.) are positioned in parallel and on the same plane, the air flow is improved and the heat dissipation effect is improved.
What is necessary is just to design suitably the vertical and horizontal dimension of each radiation fin so that an antenna length may not become too long according to the characteristic of an electronic device.

  One metal plate constituting the U-shaped fin is made of a metal having good heat conductivity such as aluminum or an alloy thereof, copper or an alloy thereof. The thickness d of the thin plate is preferably 0.05 mm to 2 mm, more preferably 0.1 mm to 1.0 mm, and most preferably 0.15 mm to 0.3 mm. As the thickness increased, the amount of air passing between them decreased, and when it was too thin, the temperature at the tip of the fin decreased, and experimental results showed that these ranges were preferable. The width w of the bottom plate of the U-shaped fin is preferably 2 mm to 15 mm, more preferably 3 mm to 10 mm, and most preferably 4 mm to 7 mm. The optimum value of the fin interval is determined according to the height of the fin and the length of the fin. However, since it is better to have a larger number of fins, the experimental results show that these ranges are preferable. The height h of the U-shaped fin is preferably 5 mm to 50 mm, more preferably 10 mm to 40 mm, and most preferably 15 mm to 30 mm. The height of the fin is limited in terms of structure, and if it is too high or too low, the thermal efficiency is poor, and these ranges are desirable as a result of experiments. The interval p between the side walls of the U-shaped fins arranged in parallel is preferably 2 mm to 15 mm, more preferably 3 mm to 10 mm, and most preferably 4 mm to 7 mm. These are also for the same reason as in the case of the width w of the bottom plate of the fin. As described above, these ranges are ranges in which it is confirmed that the heat dissipation effect is large as a result of experiments. The length and width of the heat sink as a whole are determined by the amount of heat to be radiated, heat dissipation performance such as an allowable temperature rise, and the space allocated to the heat sink in terms of the dimensions of the heating element and the device design.

  The shape of the U-shaped fin of the present invention is not necessarily limited to that in which the side wall rises at a right angle from the bottom. In the rising portion of the U-shaped fin toward the open portion, the side wall may be once reduced in the width direction from the bottom plate of the closed portion and then risen toward the open portion. By adopting such a shape, the heat transfer area from the heat transfer substrate at the bottom can be increased, and the heat of the heat transfer substrate can be easily transferred to the fins.

  As another shape of the U-shaped fin of the present invention, a structure in which a thin metal plate on the side wall is bent at the apex of the side wall of the U-shaped fin can be taken. By adopting such a structure, the height of the fin is limited, but it is suitable when it is desired to increase the surface area of the fin. It is preferable that the direction of bending is the same for all side walls. The angle of bending is preferably 1 degree or more and less than 90 degrees, more preferably 10 degrees or more and 60 degrees or less.

  In the heat sink according to the embodiment of the present invention, a plurality of U-shaped fins are arranged in parallel in a certain direction at intervals on the heat transfer substrate, and the back side surface of the bottom plate of the closed portion is joined to the heat transfer substrate. It is characterized by that. When the heating element is a flat plate, the heat transfer substrate of the present invention is also a flat plate along the heating element. The side walls of the plurality of U-shaped fins are arranged in parallel with the plurality of side walls of the U-shaped fins. By arranging in parallel in this way, the flow of air heated by the fins is directed in a certain direction, and the convection effect is improved. As described above, it is desirable that the side wall intervals between the plurality of U-shaped fins are uniform on the side walls arranged in parallel with a space therebetween. This is because the heat transfer substrate can be uniformly cooled.

  If the heat transfer from the heating element is not uniform and is locally high in the heat transfer board, increase the number of U-shaped fins in that part and close the side wall spacing in that part. You can also. By doing so, the heat sink as a whole can be cooled uniformly.

  When the heating element is a curved surface, the heat transfer substrate of the present invention is also preferably curved along the heating element. The plurality of U-shaped fins can be arranged in the normal direction of the curved surface of the heat transfer substrate. As a result, the air flow heated by the fins is evenly dissipated toward the entire curved surface, and the convection effect is improved. In this case, the U-shaped fins are opened so as to spread slightly outward, and a plurality of side walls of the U-shaped fins are arranged in the normal direction of the curved surface of the heat transfer substrate. The convection effect of the air heated by the radiating fin is further improved.

  The U-shaped fin and the heat transfer substrate in the present invention are preferably surface-treated with a heat-resistant black paint such as black alumite treatment. This is because the heat dissipation coefficient is increased by the black surface treatment.

  According to the embodiment of the present invention, it is possible to provide a heat sink having a large heat dissipation effect despite being thin and lightweight. In addition, the heat sink according to the embodiment of the present invention has a structure in which heat radiation fins are formed of parallel side walls of thin metal plates and the upper part has an open structure, so that air heated by the heated side walls can be easily removed. Can do. Moreover, since the heat sink which concerns on embodiment of this invention is a structure which can take the joining area of a heat-transfer board | substrate and a radiation fin large, it can be set as the heat sink with the sufficient heat-transfer efficiency from a heat-transfer board | substrate to a radiation fin. In addition, the heat sink according to the embodiment of the present invention is a U-shaped heat dissipation fin with a simple structure, and since it has a simple structure, manufacturing is easy and cost is low. Further, in the present invention, when the heat transfer substrate and the heat radiating fin are bonded, an adhesive is used to bond the heat transfer substrate so as not to cause processing strain or thermal distortion, thereby generating the heating element and the heat transfer substrate. It becomes a heat sink with good adhesion. Further, in the embodiment of the present invention, the heat transfer substrate and the U-shaped fins are adhesive-bonded, so that workability when a large number of fins are bonded to the heat transfer substrate is good. Further, in the heat sink according to the embodiment of the present invention, the height of the fin and the interval between the parallel portions can be freely set, so that the heat sink corresponding to various electric devices can be easily manufactured. Moreover, since the heat sink according to the embodiment of the present invention can be configured to increase the area of the bottom plate without changing the surface area of the fin, the heat transfer area is increased and the thermal resistance is reduced. Further, even when the heating element is a curved surface, it becomes a heat radiating fin along that, and in that case, it can be a fin with good heat radiating efficiency.

  FIG. 2 shows a cross-sectional view of an example of a U-shaped fin according to an embodiment of the present invention. The U-shaped fins 2a, 2b, 2c,... Shown in this figure are formed from the bottom plates 4a, 4b, 4c,... To the side walls 7a-1, 7a-2, 7b-1, 7b-2, 7c- 1, 7 c-2,... Stand upward at a right angle, and the upper part is open. The plurality of U-shaped fins 2 are desirably arranged in parallel with a constant interval p. The U-shaped fin 2 has a fin thickness d. The thickness of the fin means the thickness of the side walls 7a and 7b, and the bottom plate 4 is usually the same, but the thickness of the bottom plate can be changed. The distance q between the side walls 7a-1 and 7a-2 of the U-shaped fin 2 is preferably substantially equal to the interval p at which the plurality of U-shaped fins are arranged in parallel. The width w of the back side surface 8 of the bottom plate 4 joined to the heat transfer substrate 3 is substantially equal to q + 2d in this figure.

  FIG. 3 is a sectional view showing another example of the U-shaped fin according to the embodiment of the present invention. A case is shown in which the rising portion of the side wall of the U-shaped fin from the bottom plate toward the open portion includes a side wall that rises after being reduced in the width direction from the bottom plate of the closed portion. FIG. A shows a case where the side walls 13a and 13b rise from the bottom plate 12 of the U-shaped fin 11 to the inside at an angle α. In FIG. B, an example in which the rising angle α from the bottom plate 15 of the U-shaped fin 14 to the inside of the side walls 16a and 16b is close to zero is included in the present invention. In these drawings, the width w to be joined to the heat transfer substrate on the back side of the bottom plates 12 and 15 is w> q + 2d. Even with such a structure, the heat transfer width w can be increased while keeping the distance p between the sidewalls of adjacent U-shaped fins constant, so that the heat transfer area can be increased and the heat transfer efficiency can be improved. It was.

  FIG. 4 is a sectional view showing another example of the U-shaped fin according to the embodiment of the present invention. When using the U-shaped fins of the present invention, the height of the heat sink may be limited due to the limitations on the size of the device. In such a case, there is a case where it is desired to reduce the height without changing the surface area of the fin as a heat sink of the heat sink so much. As such an application example, a case where a sheet metal is bent at the apexes of the side walls 22a and 22b of the U-shaped fin 21 is illustrated. The direction of bending is preferably bent in a certain direction as shown in FIG. A structure in which the side walls 26a and 26b of the U-shaped fin 25 face outward from the inside (FIG. B) or inwardly can also be adopted.

  FIG. 5 is a sectional view showing an example of the heat sink 31 when the heat transfer substrate is a curved surface. This is a case where the heating element 32 has a curved surface and the heat transfer substrate 33 has a curved surface. The back side of the bottom plates 35a, 35b, 35c, 35d, ... of the U-shaped fins 34a, 34b, 34c, 34d, ... are transmitted by the adhesive layers 36a, 36b, 36c, 36d, ... Bonded to the thermal substrate 33. In this figure, the side walls 37a-1, 37a-2, 37b-1, 37b-2, 37c-1, 37c-2, 37d-1, 37d-2,. The case of standing in the direction perpendicular to the base 35 is illustrated. Further, center lines a, b, c, d,... Between the sidewalls of these U-shaped fins are arranged in the normal direction of the curved surface of the heat transfer substrate 32.

  FIG. 6 is a sectional view showing a heat sink 41 which is another example in the case where the heat transfer substrate is a curved surface. This is a case where the heating element 42 has a curved surface and the heat transfer substrate 43 has a curved surface. The back side of the U-shaped fins 44a, 44b, 44c, 44d,... With the open part opened to the outside is the adhesive layer 46a, 46b, 46c, and the back side of the bottom plates 45a, 45b, 45c, 45d,. It is joined to the heat transfer substrate 43 by 46d,. Each of the U-shaped fin side walls 47a-1, 47a-2, 47b-1, 47b-2, 47c-1, 47c-2, 47d-1, 47d-2,. Are arranged in the normal direction of the curved surface. 5 and 6 show the case where the surface of the heat transfer substrate has a semicircular curved surface, other curved surfaces such as a cylinder and an ellipse may be used.

  A pure aluminum plate (JISA1100) having a thickness of 0.2 mm, a width of 60 mm, and a length of 41.8 mm is bent at a right angle, the height h is 18 mm, the width w for joining to the heat transfer substrate is 5.6 mm, and between the side walls Six U-shaped fins having a distance q of 5.2 mm were manufactured. These U-shaped fins were black-anodized by surface treatment. A pure aluminum plate (JISA1100) having a thickness of 2 mm, a width of 60 mm, and a length of 60 mm was used as a heat transfer substrate, and black anodized by surface treatment. The distance p between the sidewalls of the six U-shaped fins adjacent to the six U-shaped fins on this heat transfer substrate is 5.2 mm, and the open side of the side faces in a certain direction as shown in FIG. Were arranged in parallel at intervals. The heat transfer substrate and these U-shaped fins are mainly epoxy resin, and Mn-Zn ferrite is blended as a heat conductive filler, and the heat conductivity when cured is 1.0 W / m ° C. One heat sink was manufactured by bonding with the above high thermal conductive adhesive. In this heat sink, a platinum ceramic heater was used as a heating element, and bonded with a heat conductive double-sided adhesive tape. The heat sink obtained had a thermal resistance of 4.8 ° C./W and very good heat conductivity.

  The heat sink manufactured by the present invention is used as an electric component that dissipates heat generated from various electronic devices and electric devices such as lamps.

The perspective view which shows the example of the heat sink which concerns on embodiment of this invention. Sectional drawing which shows the example of the U-shaped fin in this invention. Sectional drawing which shows the other example of the U-shaped fin in this invention. Sectional drawing which shows the other example of the U-shaped fin in this invention. Sectional drawing which shows the example of the heat sink which concerns on embodiment of this invention in case a heat-transfer board | substrate is a curved surface. Sectional drawing which shows the other example of the heat sink which concerns on embodiment of this invention in case a heat-transfer board | substrate is a curved surface.

Explanation of symbols

1: heat sink, 2: heat radiation fin (U-shaped fin), 3: heat transfer board, 4: bottom plate,
5: adhesive layer (first and second adhesive layers), 6: heating element, 7: side wall, 8: back side surface.
11: U-shaped fin, 12: Bottom plate, 13: Side wall,
14: U-shaped fin, 15: Bottom plate, 16: Side wall.
21: U-shaped fin, 22: Side wall,
25: U-shaped fin, 26: Side wall.
31: heat sink, 32: heating element, 33: heat transfer board,
34: U-shaped fin, 35: Bottom plate, 36: Adhesive layer, 37: Side wall.
41: heat sink, 42: heating element, 43: heat transfer board,
44: U-shaped fin, 44: Bottom plate, 45: Adhesive layer, 46: Side wall.

Claims (7)

A plurality of heat dissipating fins each individually processing a metal plate;
A heat transfer substrate in contact with the heating element;
A heat sink comprising an adhesive layer interposed between the heat radiation fin and the heat transfer substrate to bond them.   The heat sink according to claim 1, wherein the adhesive layer is electrically insulating and has high thermal conductivity.   The heat sink according to claim 1, wherein the adhesive layer is electrically insulating and radio wave absorbing.   The heat radiation fin is a U-shaped fin formed by bending a single metal plate into a U-shape, or an L-shaped fin formed by bending a single metal plate into an L-shape. The heat sink according to any one of claims 1 to 3, wherein a bottom plate which is a closed portion of the L-shaped fin or a back side surface of the bottom plate of the L-shaped fin is bonded to the heat transfer substrate.   The heat sink according to claim 2, wherein the adhesive layer includes a heat conductive filler and a resin binder as main components.   The heat sink according to claim 3, wherein the adhesive layer includes a ferrite powder, a thermally conductive filler, and a resin binder as main components.   The heat sink according to any one of claims 1 to 6, wherein a plurality of the radiation fins are arranged apart from each other in a direction along one side of the heat transfer substrate and a direction along a side orthogonal to the one side.

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