KR100554096B1 - A heat sink having a liquid - Google Patents

Abstract

The present invention relates to a heat sink fixed to an electronic component for dissipating heat from the electronic component or device, and more particularly, a heat sink in which a liquid is embedded in a space formed between the heat absorbing member and the heat dissipating member. The heat source is attached to the outer surface of the heat absorbing member, and the inner surface is circular or polygonal in succession at a predetermined interval so as to increase the boiling speed of the liquid contained in the space to double the heat diffusion. A plurality of protrusions are formed, one side of the heat dissipating member is opposed to the heat absorbing member, and the other side is characterized in that the heat dissipation fin is attached.

Accordingly, it is possible to quickly and efficiently heat the electronic components having a high heat generation.

      Heat Sink, Projection, Heat Dissipation, Cooling, Heat Sink

Description

A heat sink having a liquid

1 is a cross-sectional view of a conventional air-cooled heat sink.

2 is a cross-sectional view of a conventional liquid-embedded heat sink.

Figure 3 is a perspective view of the liquid embedded heat sink of the present invention.

Figure 4 is a front view showing a state in which protrusions are formed on the inner surface of the heat absorbing member of the present invention.

5 is a cross-sectional view of a liquid embedded heat sink of the present invention.

Figure 6 is a perspective view of one embodiment of a liquid-containing heat sink of the present invention.

7 is a schematic view of the experimental apparatus of the present invention.

8 is a schematic view of an experimental apparatus of the present invention.

Figure 9 is a perspective view showing the numerical value of the projection formed on the heat absorbing member according to the experiment of the present invention.

Figure 10 is a photograph showing the boiling surface when the heat flux according to the experiment of the present invention 90W.

Figure 11 is a photograph showing the boiling surface when the heat flux according to the experiment of the present invention 180W.

Figure 12 is a schematic diagram of the projection of the heat sink according to the experiment of the present invention.

Figure 13 is a distribution of the surface temperature of each type according to the experiment of the present invention.

14 is a diagram showing each type of surface thermal image according to the experiment of the present invention.

Figure 15 is a schematic diagram of the projection according to the experiment of the present invention.

16 is a heat resistance distribution diagram according to the heat flux of each type according to the experiment of the present invention.

Figure 17 is a view showing the thermal image of each type when the heat flux is 90W according to the experiment of the present invention.

18 is a view showing each type of thermal image when the heat flux is 180W according to the experiment of the present invention.

19 is a view showing each type of thermal image when the heat flux is 270W according to the experiment of the present invention.

20 is a view showing the thermal image of each type when the heat flux is 360W according to the experiment of the present invention.

※ Explanation of code about main part of drawing ※

1000: heatsink

100: heat dissipation member 110: cooling fins

200: heat absorbing member 210: protrusion

220: injection hole 230: air hole

300: space 400: liquid

500: heating element

The present invention relates to a heat sink that is fixed to the electronic component for dissipating heat from the electronic component or the device, and more particularly, is formed at a predetermined interval on the inner surface of the heat absorbing member to which the heat source is attached. The present invention relates to a liquid-embedded heat sink in which a plurality of protrusions are formed so as to increase the boiling speed of the embedded liquid to double the thermal diffusion.
In general, the performance of portable and desktop computers has been improved to the performance of large computers in the 1980s. As the development of high-speed CPU (Central Processing Unit 0 and high-integrated memory devices), the power consumption of electronic products is increased and thermal interference between components Due to this, the internal heat generation was increasing rapidly.
Electrical components such as semiconductor devices mounted in the above-mentioned various electric devices have high integration degree and high output, and the reliability of electronic products due to the increase in heat generation has been emerging as a new problem.
Therefore, the cooling of electric parts having heat generating portions has become an important technical problem, and the improvement of the cooling technique has attracted attention. As a method of preventing overheating of electrical parts requiring such cooling, a natural convection or forced convection using a heat sink has been mainly used.
The heat sink is manufactured by extruding or machining in a fin shape using a material having good thermal conductivity such as aluminum and copper in order to increase the heat transfer area with a cooling medium (air, water, etc.). Therefore, it is mainly attached to high heat generation electronic products to increase the cooling efficiency.
1 shows a coupling structure of a conventional heat sink as described above, a circuit board, a heat generating element 2 provided on the circuit board, a base 3a in close contact with at least one surface of the heat generating element, and An aluminum heat sink 3 composed of a plurality of heat dissipation fins 3b provided at a predetermined interval on an outer side surface of the base 3a; It consisted of a fastener assay 4 for stably fixing the heat sink to a circuit board.
Here, the heat sink 3 is formed by forming the molten metal into the molding space of the extrusion mold and molded into the base 3a and the heat dissipation fins 3b, or in a state in which the base 3a and the heat dissipation fins 3b are separately provided. It consisted of the press-fit type which fixes each heat sink fin to the base 3a using an adhesive agent.
However, the above-described conventional heat sink 3 emits heat generated from the heating element to the outside depending on the unit surface area according to the thickness of each base 3a and the heat dissipation fins 3b, the number, size, and spacing of the heat dissipation fins. Because of the structure, there was a problem that the thermal conductivity of each base and the heat sink fin of the heat sink, thermal diffusion rate and the amount of emission is fundamentally limited.
Therefore, much attention has been paid to heat pipes using liquids due to the limited space for installing heat sinks and increasing heat generation.
Heatpipe technology has been established and grown over the last 50 years since Grover at Los Almos Laboratories in the United States published its first findings in 1952. Since the 1980s, heat pipe technology has continued to be achieved not only in the extreme sectors, but also in the technical and commercial sectors in the field of electrical and electronics, by realizing high efficiency cooling devices with features such as small size, low thermal resistance, various structures, safety, long life and low maintenance cost. It was continuing to develop.
As another conventional technique for reflecting the above-mentioned trend and solving the conventional problems, it is well represented in Japanese Patent Application Laid-open No. Hei 11-317482 "heatsink".
2 is a view illustrating a coupling structure of the heat sink of Japanese Patent Laid-Open No. 11-317482, wherein the heat absorbing member 20 mounted on the heat generating element 21, the container portion, and the heat dissipation fin portion 31 are combined. The formed heat dissipation member 30, the space part 50 formed by the combination of the heat absorbing member 20 and the heat dissipation member 30, and a predetermined working liquid 40 accommodated in the space part were included.
The technique shown in Japanese Patent Laid-Open No. 11-317482 is based on the phase change caused by the boiling of the working liquid 40 enclosed in the space 50 and the movement of the working liquid in the space 50. By carrying out the transport of heat, there was an advantage to cool the electrical components more efficiently than the conventional heat sink, but there were the following problems.
First of all, the factors affecting the boiling of the working liquid are factors such as pressure, surface condition, non-condensing gas, wettability, etc., and the factors affect each other, and the surface shape most affects boiling. .
However, according to the related art, the wall surface of the space in which the working liquid 40 is accommodated, that is, the inner surface of the heat absorbing member 20 and the heat radiating member 30 is composed of a base plate.
Therefore, the heat sink provided with the flat surface as described above has a high heat resistance that prevents heat conduction when the heat flux is changed (for example, 90w-360w), and the heat absorbing member 20 and the heat radiating member 30 Since the surface temperature deviation (the lower the better the thermal spreading performance) of the inner surface of the) is severe, there is a problem that the heat diffusion decreases with the increase of the heat flux, and the size of the local heat source is large.

The present invention is to solve the above problems, a plurality of protrusions are formed on the inner surface of the heat absorbing member to which the heat source is attached at regular intervals to increase the boiling speed of the liquid contained in the space portion to double the heat diffusion. It aims to do it.
In addition, the object of the present invention is to reduce heat resistance of the heat sink by improving the heat spreading and to efficiently move heat.
In addition, an object of the present invention is to enable a rapid discharge of heat generated from a heating element provided in a corresponding device without increasing the size of various compact electronic devices such as a mobile phone or a PDA.

여기서 T_h, T_out 는 히터온도와 외기온도이며 Q는 열유속, n은 총 온도 측정지점을 나타낸다.
도 13은 흡열부재(200)의 온도분포를 나타낸다. 온도는 모두 외기온도를 차감한 것이다. 현재 널리 사용되고 있는 종래의 기술은 솔리드 베이스 플레이트(solid base plate) 히트싱크(1000)의 히터 표면온도가 Type1(Type2)보다 약 14℃(12℃) 높은 것을 볼 수 있다. 이것은 Type1, Type2에서 내부의 FC-72의 비등으로 인해 스프레딩 저항이 감소하였기 때문이다.
[표 1]
열저항과 표면 온도편차
base plate Type1 Type2 R 0.405 0.311 0.324 σ 3.2377 1.9704 1.9906
표 1은 각 경우의 열저항과 종래의 솔리드 베이스 플레이트의 표면 온도편차를 정리하여 나타낸 것이다. Type1(Type2)의 열저항이 종래의 솔리드 베이스 플레이트 보다 약 23%(20%) 낮은 것을 알 수 있다. 베이스 표면 온도편차는 열 스프레딩 성능을 나타낸다. 베이스 표면 온도편차는 Type1과 Type2가 종래의 솔리드 베이스 플레이트 보다 약 38% 더 낮은 것을 알 수 있다.
스프레딩 성능을 알아보기 위해 표면의 열화상 이미지를 비교하여 도 14에 나타내었다. Type2의 표면의 온도분포가 종래의 솔리드 베이스 플레이트 보다 약 20 ～ 30% 낮은 결과를 보였다. 또한 Type2 보다 Type1이 더 좋은 성능을 보였다.
앞선 결과를 바탕으로 실제 80watt급 이동통신 함체에 쓰이는 히트싱크(1000)에 적용하였다. 아래의 표 2는 제작한 히트싱크(1000)의 치수를 나타낸다. Type1은 종래의 히트싱크(1000)(solid base plate)이며, Type2는 본 발명에 따른 히트싱크로서, 도 15와 같이, 돌기의 가로의 길이가 1mm 이고, 돌기 사이의 간격은 1mm 인 것이다.
실험은 동일한 외기조건에서 수행하였으며 열유속을 90 ～ 450w로 증가시키면서 수행하였다. FC-72의 충진량은 약 200ml로 일정하게 유지하였다.
[표 2]
L W H t S b Type1 400 450 80 1.5 9.5 15.5 Type2 400 450 80 1.5 9.5 24
Type1과 Type2를 열유속을 변화시키면서 열저항을 비교하여 도 16에 나타내었다. Q=90W인 경우에는 Type1이 Type2보다 낮은 열저항을 보인다. 이것은 내부 FC-72가 비등하지 않고 오히려 열확산을 방해하기 때문이다. 열유속이 증가함에 따라 Type2가 Type1보다 더 낮은 열저항을 나타내며 평균적으로 약 9.3% 더 낮은 것을 알 수 있다.
이는 앞선 결과와 같이 FC-72가 비등하면서 열확산을 증가시키기 때문이다.
도 17 내지 도 20에 도시된 바와 같이, 열유속에 따른 종래의 솔리드 베이스 플레이트와 본 발명의 흡열부재(200) 표면의 열화상이미지이다. Q=90W인 경우, 도 17과 같이, Type1의 종래의 솔리드 베이스 플레이트의 온도 분포가 Type2보다 균일하며 국부열원의 크기가 더 작은 것을 볼 수 있다. 이는 Type2에서 액체(400)가 비등하지 않고 열확산을 오히려 억제하기 때문이다, 그러나 열유속이 증가함에 따라(도 18 내지 도 20) 내부의 작동 액체(400)가 비등하고 열확산을 증가시켜 Type2의 온도분포가 Type1보다 균일하고 국부열원의 크기가 더 작은 것을 볼 수 있다.
결과적으로 열유속이 증가함에 따라 본 발명에 따른 돌기(210)를 구비한 히트싱크(1000)인 Type2가 점점 종래의 솔리드 베이스 플레이트인 Type1보다 낮은 열저항을 나타내며 평균적으로 약 9.3% 낮은 것을 알 수 있었다.
본 발명은 상기한 실시 예에 한정되지 않고, 이하의 특허청구범위에서 청구하는 바와 같이 본 발명의 요지를 벗어남 없이 당해 발명이 속하는 분야에서 통상의 지식을 가진 자라면 누구든지 다양한 변경 실시가 가능한 범위 까지 본 발명의 기술적 정신이 있다고 할 것이다.The present invention for achieving the above object is a heat sink in which a liquid is embedded in the space formed between the heat absorbing member and the heat radiating member, the heat source is attached to the outer surface of the heat absorbing member, the inner surface is embedded in the space portion In order to increase the boiling rate of the liquid to double the heat diffusion, a plurality of projections having a flat or circular cross-section is formed continuously at predetermined intervals, one side of the heat dissipating member is opposed to the heat absorbing member, the other side It is characterized in that the heat radiation fin is attached.
Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.
As shown in FIG. 3, the liquid-embedded heat sink 1000 has a heat absorbing member 200, a heat dissipating member 100, a body consisting of a heat absorbing member 200 and a heat dissipating member 100, a protrusion 210, and a heat dissipating fin ( And 110).
The heat absorbing member 200, the heat dissipating member 100, the protrusion 210, and the heat dissipation fin 110 of the heat sink 1000 have thermal conductivity such as aluminum and copper to increase the heat transfer area with the cooling medium (air, water). It is manufactured by extrusion or machining with good materials.
The heat absorbing member 200 is a heat source is attached to the outer surface, a plurality of protrusions 210 are formed on the inner surface, is combined with the heat radiation member 100 to be described later to form a space 300 therein.
The heat source attached to the outside of the heat absorbing member 200 preferably includes a heat generating element 500 such as an electronic component installed on a circuit board.
In addition, the inner surface of the heat absorbing member 200 is formed with a penetrating injection hole 220 to inject or discharge the liquid 400 into the space portion 300, the liquid 400 to the space portion 300 When the air in the space 300 is injected, or when the liquid 400 is injected, the air hole 230 is formed so that the air can be discharged for sealing the space 300.
The protrusion 210 is formed on the inner surface of the heat absorbing member 200 and is continuously formed at predetermined intervals so as to increase the boiling speed to double the thermal diffusion and reduce the thermal resistance.
When the projection 210 is described in more detail, the projection 210 may be formed in a circular cross section or a polygon, and may be continuously formed up, down, left, or right at predetermined intervals, or may be alternately formed up, down, left, and right. Preferably the planar cross section is formed in a square.
And the protrusion 210 is formed in the range of 0.5 to 5mm in length and width, the interval between the protrusions 210 is formed in the range of 0.5 to 5mm, the height of the protrusion 210 is in the range of 0.5 to 5mm Is formed in, the interval between the top of the protrusion 210 and the inner surface of the heat dissipation member 100 is to be formed in the range of 0.5mm or less.
Accordingly, the upper end of the protrusion 210 and the inner surface of the heat dissipation member 100 may be in contact with each other to allow the liquid 400 to boil between the protrusion 210 and the protrusion 210.
The protrusion 210 has a horizontal length and a vertical length of 1 mm, a distance between the protrusions 210 is 1 mm, and a height of the protrusion 210 is 2 mm, based on the experimental results described later, and an upper end of the protrusion 210. And the interval between the inner surface of the heat dissipation member 100 is preferably formed in the range of 0.1mm to 0.2mm.
In addition, the protrusion 210 has a length of 2 mm in length and width, and a distance between the protrusions 210 is 2 mm, and a height of the protrusion 210 is formed at 2 mm, and the upper end of the protrusion 210 and the heat dissipation member 100. The distance between the inner surface of the c) is preferably formed in the range of 0.1 mm to 0.2 mm.
In addition, the protrusion 210 has a length of 1 mm in length and width, and a distance between the protrusions 210 is 3 mm, and a height of the protrusion 210 is formed at 2 mm, and the top of the protrusion 210 and the heat dissipation member 100. The distance between the inner surface of the c) is preferably formed in the range of 0.1 mm to 0.2 mm.
In addition, the projections 212, as shown in Figure 6, the flat cross-section is formed in a rectangular, may be formed to be continuous to the left and right, and may also be alternately arranged in the longitudinal direction.
The protrusion 210 is formed by cutting a plane using a cutting machine.
In addition, the numerical value of the protrusion 210 as described above is to perform a performance test through the experiment described later.
One side of the heat dissipation member 100 is formed to face the heat absorbing member, and the other side of the heat dissipation fin 110 is fixed.
Referring to the fixing method, the edge portion of the heat radiating member 100 and the heat absorbing member 200 in the state in which the heat absorbing member 200 is aligned on the edge of the heat radiating member 100, the adhesive, soldering Sealing by welding, or the like, is fixed and coupled using bolts or screws using fastening holes 240 formed at the edges of the heat absorbing member 200 and the heat dissipating member 100.
Therefore, in the state in which the heat dissipation member 100 and the heat absorbing member 200 are combined, a space part 300 is formed inside the heat absorbing member 200 and the heat dissipation member 100, and the space part 300 is disposed in the space part 300. The liquid 400 having a predetermined boiling point is injected into the inside to prevent the heat generating element 500 from being leaked to the outside by the thermal pressure.
The liquid 400 may be in the form of a mixture of water, oil, alcohol mixture, polymer liquid material or conductive solid particles, preferably using FC-72.
The FC-72 is chemically stable, has an insulating property, and has a relatively low boiling (also referred to as boiling, a phenomenon in which vaporization occurs from inside the liquid 400). It is a good working liquid.
Therefore, the space 300 serves to transport heat by a phase change such as a liquid phase from the liquid phase to the gas phase and the gas phase by boiling of the liquid 400 introduced into the space 300.
Accordingly, while the air in the space 300 is discharged to the outside through the air hole 230 formed on the heat absorbing member 200, a predetermined amount of the liquid 400 is introduced into the space 300 through the injection hole 220. After the injection, the air hole 230 and the injection hole 220 are sealed using an adhesive or welding, and the space 300 is in a vacuum state.
Due to the vacuum of the space 300 as described above, it is possible to prevent distortion and damage of the main body by boiling and to use the device semi-permanently.

The heat dissipation fins 110 are attached to the other side (outside) of the heat dissipation member to quickly dissipate heat generated from the main body into the air, and a plurality of slots are spaced a predetermined distance from the other side of the heat dissipation member 100. Are attached in parallel.
Therefore, the heat dissipation fin 110 increases the heat dissipation rate by increasing the heat dissipation area per unit area of the heat absorbing member.
In addition, the heat dissipation fins 110 are dug into the indentation grooves on the other side of the heat dissipation member 100 and a conductive adhesive mixed with a curing agent such as aluminum powder is adhered to the heat dissipation fins 110 to be inserted into the indentation grooves and fixed.
In addition, the heat dissipation fins 110 may have a plurality of slots arranged in parallel to the left and right, and the heat dissipation fins 110 having a circular cross section or a circular cross section may be provided at regular intervals in a horizontal direction.
Hereinafter, the operation principle of the present invention will be described.
As shown in FIG. 5, when the heat applied from the heat generating element 500 (heat source) is applied to the heat absorbing member 200 of the main body, the liquid 400 in the space 300 becomes boiled, and the liquid 400 ) Evaporates and releases heat, and the vapor of the liquid 400 is cooled again to return to the liquid 400 state. Therefore, the liquid 400 returned to the liquid 400 again is refluxed again, and heat is moved to the heat radiating fin 110 of the heat radiating member 100 by the phase change of the liquid 400. Heat radiation efficiently.
At this time, the inner surface of the liquid 400 and the heat absorbing member 200 and the surface of the liquid 400 are increased by the plurality of protrusions 210 formed on the inner surface of the heat absorbing member 200 of the main body, and the space portion ( By increasing the boiling speed of the liquid 400 contained in the 300, the effect of doubling the thermal diffusion and lowering the thermal resistance is obtained.
In addition, it lowers the standard deviation of the temperature of the inner surface of the heat absorbing member 200, and has an effect of improving the thermal spreading performance.
Hereinafter, an experiment on the action and effect of the protrusion 210 formed on the inner surface of the heat absorbing member 200 of the present invention was carried out.
First, the apparatus for the characteristic test of the heat sink 1000 according to the present invention is provided, which will be described.
7 to 8 are schematic diagrams of an experimental apparatus according to the present invention.
The cartridge heater was mounted on a square aluminum block (30 mm × 30 mm) to change the heat flux. An acrylic box (300 mm × 340 mm × 300 mm) was mounted to the back of the heat sink (1000) base to minimize heat loss.
Ten T-Type thermocouples were installed on the surface of the heat sink 1000 to measure thermal performance, and an ultraviolet image camera (Model: NEC TH7100) was used to measure the temperature distribution.
In all cases, the experiment was carried out for one day by removing the non-condensable gas (air) using a vacuum pump. In addition, the FC-72 filling amount was kept constant in all cases during the experiment. When the base surface temperature was changed by ± 0.1 ° C for 10 minutes, it was considered as a steady state, and after reaching the steady state, the temperature data was stored in a computer through a data logger.
First, the experiment was performed by changing the surface shape most affecting the boiling of the liquid 400 injected into the space 300 of the heat sink 1000.
8 shows the heat sink 1000 and the boiling surface shape used in the experiment. In order to observe boiling, acrylic was installed on the front surface of the heat absorbing member 200, and a heating element 500 and a local heat generating member were installed on the rear surface. In addition, the heat flux of the heating element 500 was maintained at 90W ~ 360W.
As shown in FIG. 9, Type1 is a flat surface having an inner surface of the space part 300 as in the conventional heat sink 1000 (hereinafter, referred to as a solid base plate), and Type2 is a protrusion 210. Is formed in a rectangular cross-section, but is formed to be continuous to the left and right, the length of the horizontal of the protrusion 210 is 1mm, the length of the vertical coincides with the length of the heat absorbing member 200, and the continuous protrusion (left and right) The spacing between 210 is formed to be 1mm.
And Type3 is a flat cross-section of the projection 210 is formed in a square, is formed so as to be continuous in the up, down, left and right at a predetermined interval, the horizontal length of the projection 210 is 2mm, the interval between the projections 210 It is 2mm, Type4 is formed with a projection 210 is formed in a rectangular, continuous up, down, left and right at a predetermined interval, the horizontal length of the projection 210 is 1mm, the interval between the projections 210 1mm.
The height of the protrusion 210 is all formed in 2mm, the interval between the upper end and the inner surface of the heat dissipation member 100 is formed of 0.1mm or 0.2mm.
First, the boiling surface at 90W of heat flux is shown in FIG. Type 1 and 3 can be seen that no boiling occurs, and type 2 and 4 can be seen that the boiling is active.
11 is a boiling surface photograph at a heat flux of 180W. Boiling occurs in all cases starting from 180W, while Type 4 shows the most active boiling.
The results indicated that the filling amount of the same liquid 400 was maintained, and Type 4 showed the most active boiling at the same heat flux.
Next, a thermal performance test of the heat sink 1000 was performed.
Based on the above results, the heat sink 1000 was manufactured as shown in FIG. 12. Thermal resistance and solid base plate temperature standard deviation were used for thermal performance comparison. Each definition is as follows.
First of all, the conventional heat sink is a solid base plate, and the heat sink according to the present invention is Type1, 2, as shown in Fig. 12, and the type1 has a horizontal and vertical length of the projections of 3 mm and the interval between the projections. Is 1mm, Type2 is the length and width of the projections are 2mm and the distance between the projections is also 2mm.
[Equation 1]

Where T _{h and} T _out are the heater temperature and the outside temperature, Q is the heat flux, and n is the total temperature measurement point.
13 illustrates a temperature distribution of the heat absorbing member 200. All the temperatures are subtracted from the outside temperature. The prior art, which is currently widely used, can be seen that the heater surface temperature of the solid base plate heat sink 1000 is about 14 ° C. (12 ° C.) higher than Type 1 (Type 2). This is because the spreading resistance of Type 1 and Type 2 decreased due to the boiling of the internal FC-72.
TABLE 1
Heat Resistance and Surface Temperature Deviation
base plate Type1 Type2 R 0.405 0.311 0.324 σ 3.2377 1.9704 1.9906
Table 1 summarizes the thermal resistance in each case and the surface temperature deviation of the conventional solid base plate. It can be seen that the thermal resistance of Type 1 (Type 2) is about 23% (20%) lower than that of the conventional solid base plate. Base surface temperature deviations indicate heat spreading performance. The base surface temperature deviation can be seen that Type 1 and Type 2 are about 38% lower than conventional solid base plates.
In order to examine the spreading performance, thermal images of the surfaces were compared and shown in FIG. 14. The surface temperature distribution of Type2 surface was about 20-30% lower than that of the conventional solid base plate. Also, Type1 showed better performance than Type2.
Based on the previous results, it was applied to the heat sink (1000) used in the actual 80watt class mobile communication enclosure. Table 2 below shows the dimensions of the manufactured heat sink 1000. Type 1 is a conventional heat sink 1000 (solid base plate), Type 2 is a heat sink according to the present invention, as shown in Figure 15, the horizontal length of the projection is 1mm, the interval between the projections is 1mm.
The experiment was carried out under the same ambient conditions and the heat flux was increased to 90 ~ 450w. The filling amount of FC-72 was kept constant at about 200 ml.
TABLE 2
L W H t S b Type1 400 450 80 1.5 9.5 15.5 Type2 400 450 80 1.5 9.5 24
Type 1 and Type 2 are shown in FIG. 16 by comparing the thermal resistance while changing the heat flux. When Q = 90W, Type1 shows lower thermal resistance than Type2. This is because the internal FC-72 does not boil, but rather prevents thermal diffusion. As the heat flux increases, Type2 shows lower thermal resistance than Type1, which is about 9.3% lower on average.
This is because FC-72, as shown in the previous results, increases thermal diffusion as it boils.
As shown in Figure 17 to 20, the thermal image of the conventional solid base plate according to the heat flux and the surface of the heat absorbing member 200 of the present invention. When Q = 90W, as shown in FIG. 17, it can be seen that the temperature distribution of the conventional solid base plate of Type 1 is more uniform than that of Type 2 and the size of the local heat source is smaller. This is because the liquid 400 does not boil in Type2 and rather suppresses thermal diffusion, but as the heat flux increases (FIGS. 18-20), the working liquid 400 inside boils and increases the thermal diffusion, thereby increasing the temperature distribution of Type2. Is uniform than Type1 and the size of local heat source is smaller.
As a result, as the heat flux increased, the heat sink 1000 having the protrusion 210 according to the present invention was found to have a lower heat resistance than the conventional solid base plate Type 1, which was about 9.3% lower on average. .
The present invention is not limited to the above-described embodiments, and various changes can be made by those skilled in the art to which the present invention pertains without departing from the gist of the present invention as claimed in the following claims. Until the technical spirit of the present invention will be said.

According to the liquid-embedded heat sink of the present invention according to the above configuration, a plurality of protrusions are formed on the inner surface of the heat absorbing member to which the heat source is attached at regular intervals, thereby increasing the boiling speed of the liquid contained in the space portion to double the thermal diffusion. It is effective.
In addition, the projections have an effect of lowering the heat resistance of the heat sink to improve heat spreading, thereby effectively moving heat.
In addition, there is an effect that can quickly discharge the heat generated from the heating element provided in the device without increasing the size of various compact electronic devices, such as a mobile phone or PDA.

Claims (5)

delete In a heat sink in which a liquid is embedded in a space formed between a heat absorbing member and a heat radiating member, A heat source is attached to an outer surface of the heat absorbing member, and a plurality of flat cross sections are circular or polygonal in succession at predetermined intervals so as to increase the boiling rate of the liquid contained in the space part and to double the heat diffusion. Protrusions are formed, The heat dissipation member is a liquid-containing heat sink, characterized in that one side is opposed to the heat absorbing member, the other side is attached to the heat radiation fin. The method of claim 2, The protrusions are continuously formed up, down, left and right, and the length of the horizontal and vertical is 0.5 ~ 5mm, The interval between the projections is 0.5 to 5mm, The height of the protrusion is 0.5 to 5mm, The gap between the upper end of the projection and the inner surface of the heat dissipation member is a liquid-containing heat sink, characterized in that less than 0.5mm. The method of claim 2, The projections A flat cross-section is formed in a rectangular, liquid-containing heat sink, characterized in that formed in succession left and right. The method according to any one of claims 2 to 4, Inside the heat absorbing member A through hole is formed to inject or discharge the liquid into the space part, When the liquid is injected into the space portion, the air in the space portion is discharged, or a liquid-embedded heat sink characterized in that the through-hole air hole is formed so as to discharge the air for sealing the space portion.

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