JP2000035294A - Plate type heat pipe and cooling structure using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain performance of certain degree in a top heat mode by extending a wick member partly brought into contact with a heat radiating side main surface wall along a heat transfer block to a heat absorbing side main surface wall, and forming an end of the member brought into contact with the heat absorbing side main surface wall in a substantially flatly aligned state. SOLUTION: In the case that the plate type heat pipe 10 is inverted or largely inclined a circulation of a condensed working fluid by its gravity operation cannot be expected. In such a case, a wick member 30 is extended to a heat absorbing side main surface wall 1000 along the block 20, and the condensed fluid is circulated by a capillarity of the member 30. Further, since an end of the member 30 is brought into contact with the wall 1000 in the state that it is substantially flatly aligned, the fluid moved by the capillarity is more effectively arrived at the wall 1000.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plate-type heat pipe suitable for cooling electric and electronic parts such as semiconductor elements and a cooling structure using the same.

[0002]

2. Description of the Related Art Electric and electronic components such as semiconductor elements mounted on various devices such as personal computers and electric and electronic devices such as electric power equipment generate a certain amount of heat when used. If the temperature of such an electric / electronic component rises excessively, its performance is reduced or its life is shortened. In recent years, the miniaturization of electric devices represented by personal computers and the like has been progressing, and attention has been paid to a technology for cooling electric and electronic components mounted thereon.

[0003] Electric and electronic elements that require cooling are hereinafter referred to as parts to be cooled. As a method of cooling the component to be cooled, for example, an air-cooled type, that is, a fan or the like is attached to a housing of an electric device mounted thereon and an atmosphere in the housing is cooled to prevent an excessive rise in temperature of the component to be cooled. Methods are known. This method is particularly effective for relatively large electric equipment.

In addition to the air-cooling method described above, in recent years, a method of connecting a heat sink or a fin to a component to be cooled and dissipating heat via the heat sink has become effective. In some cases, a heat pipe is interposed between the heat sink or the fin and the component to be cooled. There is also known a technique in which an electric fan blows the heat sink, the fins, and the like to achieve higher cooling efficiency.

[0005] Here, the heat pipe will be described slightly. The heat pipe has a sealed cavity, and heat is transferred by phase transformation and movement of the working fluid contained in the cavity. There is also a heat transfer that conducts heat in a container (container) that constitutes a heat pipe, but usually, it is relatively small compared to the heat transfer described above.

[0006] The operation of the heat pipe is briefly described as follows. Taking a rod-shaped heat pipe as an example, a heating component (component to be cooled) is connected near one end thereof, and a fin for heat dissipation is attached near the other end. In the part to which the component to be cooled is attached (referred to as a heat absorbing part, a heat absorbing side, etc.), the working fluid evaporates due to the heat transmitted through the thick part of the container, and the vapor is attached to the fin (the heat radiation part). Part, called the heat dissipation side). Then, the vapor returns to the liquid phase again, and the heat is generally released to the outside via the fins. In this way, heat is transferred from the heat absorbing side to the heat radiating side.

[0007] In order to perform continuous heat transfer, the working fluid that has returned to the liquid phase state on the heat radiation side must be moved (refluxed) again to the heat absorption side. In the case of a gravity type heat pipe, the heat absorption side may be located below the heat radiation side (this form is called bottom heat). In this case, the working fluid in a liquid phase state due to the phase transformation is recirculated by gravity. However, when the heat-absorbing side is not located below the heat-radiating side (such a form is called top heat), a wick is placed in the cavity, or a minute groove is provided on the inner wall of the cavity, and a capillary action is used. It is necessary to devise such that the working fluid returns.

The shape of the heat pipe has been attracting attention in recent years, in addition to a typical round pipe shape, a plate-shaped heat pipe. Plate-type heat pipes are sometimes called flat-type heat pipes or flat-type heat pipes.However, this plate-type heat pipe is easy to contact with a cooled element such as a semiconductor element over a wide area due to its shape. There are advantages.

[0009]

The plate type heat pipe is
There is an advantage that it can be brought into contact with the component to be cooled on its wide main surface. Even in the case of using a plate-type heat pipe, it is desirable to use it in the bottom heat mode in order to further ensure the recirculation of the working fluid, as in the case of a round pipe-shaped heat pipe. Therefore, as a desirable mounting structure, the plate-type heat pipe is arranged so that one main surface thereof faces downward, a component to be cooled contacts the lower main surface, and a heat sink is attached to the other upper main surface. Structure is conceivable. In this case, the bottom heat mode is provided since the lower main surface portion is on the heat absorbing side and the upper main surface portion to which the heat sink is attached is on the heat radiation side.

However, in recent years, miniaturization of computers and the like has progressed, and electric and electronic devices on which components to be cooled are mounted have been expanded from stationary to portable. In particular, in the case of a small computer or the like, it may be assumed that the computer is used at an angle. Under such circumstances, a plate-type heat pipe capable of maintaining a certain level of performance even in the top heat mode has been demanded.

[0011]

SUMMARY OF THE INVENTION In view of the above circumstances, the present invention has been made to develop a plate type heat pipe capable of maintaining excellent performance even in a top heat mode. The plate type heat pipe of the present invention is a plate type heat pipe having a plate type container, and a heat transfer block in contact with a heat absorbing side main surface wall of the plate type heat pipe is provided in a hollow portion thereof, and the plate type heat pipe is further provided. A wick member that partially contacts the heat-radiation-side main surface wall of the pipe extends to the heat-absorption-side main surface wall along the heat transfer block, and a tip end of the wick member that contacts the heat-absorption-side main surface wall is substantially flat. It is in a state.

It is particularly desirable that the wick member is made of a material having excellent heat conductivity. Further, it is proposed that a part of the wick member is disposed along the heat radiation side main surface wall, or that the wick member is in contact with or joined to the heat transfer block.

One or more convex portions are formed on the heat absorbing side main surface wall of the container, and the component to be cooled, which is to be cooled, is thermally connected to the convex portions. There is also. In this case, the heat transfer block may be provided at the convex portion.

As a cooling structure using the plate-type heat pipe of the present invention, the above-described plate-type heat pipe is disposed opposite to a substrate on which a component to be cooled is mounted, and the component to be cooled is attached to the plate-type heat pipe. A cooling structure with a thermally connected configuration is proposed.

[0015]

FIG. 1 is an explanatory view schematically showing an example of a plate-type heat pipe of the present invention and an example of a cooling structure using the same. The board 401 is assumed to be a printed board or the like, on which the component to be cooled 40 such as a semiconductor element is mounted. Reference numeral 400 in the figure indicates a lead.

As shown in FIG. 1A, a plate-type heat pipe 10 is arranged so as to be in contact with the upper surface of the component 40 to be cooled. The component to be cooled 40 and the plate-type heat pipe 10
In addition to direct contact, heat contact grease or the like may be interposed as necessary to make contact. In some cases, these may be joined by soldering or the like. The material of the container 100 constituting the plate-type heat pipe 10 is not particularly limited. However, it is desirable to use a material having excellent thermal conductivity such as a copper material or an aluminum material in terms of the thermal performance of the plate-type heat pipe 10. JIS standard C1020 as copper material,
Aluminum materials such as C1100 are also JIS standard A1100, A3000 series, A5000 series, A600
0 series and the like.

An appropriate amount of working fluid (not shown) is accommodated in the hollow portion 101 of the plate-type heat pipe 10. Examples of the working fluid include water, alternative Freon, ammonia, alcohol, acetone, and the like.

In the cavity 101, the part to be cooled 40
The heat transfer block 20 is disposed at a position corresponding to a portion connected to the plate-type heat pipe 10. The heat transfer block 20 is in contact with both a wall constituting the lower main surface of the container 100 (heat absorbing side main surface wall 1000) and a wall constituting the upper main surface (radiating side main surface wall 1001). The heat transfer block 20 may be metal-joined to the main surface wall by soldering, brazing, or the like. Heat transfer block 2
It is desirable to join 0 to the inner wall because the thermal resistance between them becomes smaller.

In the hollow portion 101, the wick member 30 is provided.
Is provided. The wick member 30 is arranged along the heat radiation side main surface wall 1001. The wick member 30 extends to the heat absorbing side main surface wall 1000 along the heat transfer block 20, and its tip is shown in FIG.
As shown in the schematic enlarged view of FIG.
Are cut into a substantially flat state. Since the wick member 30 is usually formed by laminating a metal mesh or the like, the tip of the wick member 30 is likely to be uneven with severe irregularities. In the present invention, the tips are aligned so as to be substantially flat.

In the vertical arrangement as shown in FIG. 1, when the component to be cooled 40 such as a semiconductor device is operated, and when the temperature of the component to be cooled 40 rises with the operation, the heat of the component to be cooled 40 becomes heat. By the operation of the pipe, the heat is transmitted to the main surface wall on the upper surface side of the plate type heat pipe 10, that is, the heat radiation side main surface wall 1001. The working fluid condensed by radiating heat on the heat-radiation-side main surface wall 1001 moves (recirculates) toward the heat-absorption-side main surface wall 1000 on the lower surface side by gravity or the like. However, when the plate-type heat pipe 10 is in an inverted or greatly inclined state, it is not possible to expect the condensed working fluid to return by gravity.

In such a case, the working fluid condensed by the capillary action of the wick member 30 returns.
In the present invention, since the tip of the wick member 30 is in contact with the heat absorbing side main surface wall 1000 of the hollow portion 101 in a substantially flat state, the working fluid displaced by the capillary action is more reliably transferred to the heat absorbing side main surface. It reaches the face wall 1000. Therefore, the recirculation operation of the working fluid in the top heat mode is more reliably maintained.

FIG. 2 shows a plate-type heat pipe 1 in a case where the lower main surface wall of the container 110 is deformed to provide projections 112 and 113 corresponding to the heights of the components 410 and 412 to be cooled.
FIG. The heat transfer block 21 is disposed in the hollow portion 111 where the component to be cooled 411 contacts. Also in this example, the wick member 31 is installed similarly to the example of FIG. That is, the tips of the wick members 31 extending to the lower main surface wall along the heat transfer block 21 are aligned so as to be substantially flat, so that the wick members 31 reliably contact the lower main surface wall. . Reference numeral 42 in the figure,
43 indicates a lead and a substrate, respectively. It was also confirmed that the recirculation of the working fluid in the top heat mode operated more reliably in the plate heat pipe 11.

The example shown in FIG.
This is a plate-type heat pipe 12 in a case where the heat transfer blocks 22 to 24 are arranged at positions where the to-442 are connected. Others are the same as the example shown in FIG. Reference numerals 120 and 12 in the figure
Reference numerals 1 and 32 denote a container, a cavity, and a wick member, respectively, and reference numerals 45 and 46 denote a lead and a substrate, respectively. It was also confirmed that the recirculation of the working fluid in the top heat mode operated more reliably in the plate heat pipe 12.

In the examples shown in FIGS. 1 to 3 described above, when the wick members 30 to 32 are each formed of a mesh made of a material having excellent heat conductivity, the wick members 30 to 32 absorb heat from the plate-type heat pipes 10 to 12. Due to the contact with the portion, the evaporation area of the working fluid is substantially increased. Therefore, the heat transport performance of these plate-type heat pipes 10 to 12 is further enhanced.

FIG. 4 is an explanatory view showing an example of a cooling structure in which a heat sink 5 for promoting heat radiation is attached to the heat radiation side of the plate type heat pipe 13 of the present invention. By employing such a cooling structure, a cooling structure excellent in space and cooling performance is realized. Reference numerals 130, 131, 2 in the figure
Reference numerals 5 and 33 denote a container, a cavity, a heat transfer block, and a wick member, respectively, reference numerals 470 to 472 denote parts to be cooled, and reference numerals 48 and 49 denote leads and substrates, respectively.

[0026]

As described above, the plate-type heat pipe of the present invention can maintain excellent performance even in the top heat mode. For this reason, the cooling structure using the plate-type heat pipe of the present invention is used by tilting the device, for example, when applied to an electric or electronic device in which a component to be cooled such as a semiconductor element to be cooled is mounted. Even in the situation, it is possible to maintain some excellent cooling performance.

[Brief description of the drawings]

FIG. 1 is an explanatory diagram showing an example of a plate-type heat pipe according to the present invention and a cooling structure using the same.

FIG. 2 is an explanatory view showing an example of a plate-type heat pipe according to the present invention and a cooling structure using the same.

FIG. 3 is an explanatory view showing an example of a plate-type heat pipe according to the present invention and a cooling structure using the same.

FIG. 4 is an explanatory view showing an example of a plate-type heat pipe according to the present invention and a cooling structure using the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Plate-type heat pipe 100 Container 101 Hollow part 20 Heat transfer block 30 Wick member 40 Component to be cooled 400 Lead 401 Substrate 11 Plate type heat pipe 110 Container 111 Hollow part 21 Heat transfer block 31 Wick member 410 Component to be cooled 411 Component to be cooled 412 Component to be cooled 42 Lead 43 Board 12 Plate heat pipe 120 Container 121 Cavity 22 Heat transfer block 23 Heat transfer block 24 Heat transfer block 32 Wick member 440 Component to be cooled 441 Component to be cooled 442 Component to be cooled 45 Lead 46 Substrate 13 Plate heat pipe 130 Container 131 Cavity 25 Heat transfer block 33 Wick member 470 Component to be cooled 471 Component to be cooled 472 Component to be cooled 48 Lead 49 Board

 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Sho Jin Furukawa Electric Co., Ltd. 2-6-1 Marunouchi, Chiyoda-ku, Tokyo

Claims (7)

[Claims] 1. A plate-shaped heat pipe having a plate-shaped container, wherein a heat transfer block in contact with a heat-absorbing-side main surface wall of the plate-shaped heat pipe is provided in a hollow portion thereof, and a heat-dissipating side of the plate-shaped heat pipe is further provided. A wick member that partially contacts the main surface wall extends to the heat-absorbing main surface wall along the heat transfer block, and a tip portion of the wick member that contacts the heat-absorbing main surface wall is in a substantially flat state. There is a plate type heat pipe. 2. The plate-type heat pipe according to claim 1, wherein said wick member is made of a material having high thermal conductivity. 3. The plate-type heat pipe according to claim 1, wherein a part of the wick member is arranged along the heat-radiation-side main surface wall. 4. The plate-type heat pipe according to claim 1, wherein the wick member is in contact with or joined to the heat transfer block. 5. The heat absorbing side main surface wall of the container is formed with one or a plurality of projections, and a cooled component to be cooled is thermally connected to the projections. The plate-shaped heat pipe according to any one of claims 1 to 4. 6. The plate-type heat pipe according to claim 5, wherein the heat transfer block is provided at the convex portion. 7. The plate-type heat pipe according to claim 1, which is disposed opposite to a substrate on which the component to be cooled is mounted, and the component to be cooled is thermally attached to the plate-type heat pipe. A cooling structure using the plate-type heat pipe according to any one of claims 1 to 6, which is connected.