JPH10267571A - Plate type heat pipe and cooling structure using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently cool an element to be cooled even when the heights of a plurality of mounted elements to be cooled are different, or even when the heat flow velocities of the elements to be cooled are different by arranging protruding parts conforming to distances between a plate type heat pipe and the elements to be cooled which are confronted with the plate type heat pipe. SOLUTION: On the lower side of a plate type heat pipe 10, elements 20, 21, 22 to be cooled such as semi-conductor elements are mounted on a print substrate 30. The heights of the elements 20, 21, 22 to be cooled from the print substrate 50 are different, and the plate type heat pipe 10 is provided so as to be confronted with the substrate on which the elements 20, 21, 22 to be cooled are mounted. Then, on the heat pipe 10, protruding parts 13 are arranged conforming to the distances to the confronted elements 20, 21, 22 to be cooled, and the elements 20, 21, 22 to be cooled are thermally brought into contact with one plate type heat pipe 10. Also, the contact between the elements 20, 21, 22 to be cooled and the plate type heat pipe 10 may directly come into contact, or may be brought into contact by inserting a heat transmitting sheet, or heat transmitting grease, etc.

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 and a cooling structure for a cooled element such as a semiconductor element using the same.

[0002]

2. Description of the Related Art Electronic components such as semiconductor elements mounted on various devices such as personal computers and electric and electronic devices such as electric power equipment are inevitable to generate a certain amount of heat by their use. It is becoming a technical issue. As a method of cooling an electric / electronic element requiring cooling (hereinafter referred to as a cooled element), for example, a fan is attached to a device,
Representatively known are a method of lowering the temperature of the air in the equipment housing, a method of particularly cooling the element to be cooled by attaching a cooling body to the element to be cooled, and the like.

As a cooling body attached to the element to be cooled, a plate made of a material having excellent heat conductivity such as a copper material or an aluminum material is used. It is more effective to attach a heat dissipating fin to such a plate or to use a plate and a fin integrally formed (by casting or forging). This type of cooling body is sometimes called a heat sink or the like.

In recent years, as a cooling body attached to an element to be cooled, a heat pipe is attached to a cooling body having a heat pipe structure or a plate material having excellent heat conductivity, such as a copper material or an aluminum material, instead of a mere heat conductive metal material. Is proposed and put to practical use.

The heat pipe has a sealed cavity, and heat is transferred by phase transformation and movement of the working fluid contained in the cavity. Of course, some heat is transferred by conducting heat through a container (container) constituting the heat pipe. However, the heat pipe is a heat transfer device mainly intended to perform a heat transfer operation by a working fluid.

[0006] The operation of the heat pipe is briefly described as follows. That is, on the heat absorbing side of the heat pipe, the working fluid evaporates due to heat transmitted through the material of the container (container) constituting the heat pipe, and the vapor moves to the heat radiation side of the heat pipe. On the heat radiation side, the vapor of the working fluid is cooled and returns to the liquid state again. Then, the working fluid that has returned to the liquid phase moves (recirculates) to the heat absorbing side again. Heat is transferred by such phase transformation and movement of the working fluid.

In the case of a gravity type heat pipe, the working fluid which has been brought into a liquid phase state by phase transformation moves (refluxes) to the heat absorbing side by gravity or capillary action. In this case, the heat absorption side may be disposed below the heat radiation side.

[0008] The working fluid in the heat pipe is usually
Water, an aqueous solution, alcohol, and other organic solvents are used. As a special application, mercury may be used as a working fluid. As described above, since the heat pipe utilizes the action such as phase transformation of the working fluid inside, the heat pipe is manufactured so as to minimize mixing of gases and the like other than the working fluid into the sealed interior. . Such contaminants are usually air (air) mixed during the production or carbon dioxide dissolved in the working fluid.

In addition to a typical round pipe shape, a heat pipe shape of a flat type has recently attracted attention. The flat type heat pipe has advantages such as easy contact with a cooled element such as a semiconductor element over a large area due to its shape.

As such a flat heat pipe, 2
There have been proposed ones in which two flat plates are joined by welding or the like so that a cavity is formed between them, or one in which two flat plates partially coated with a release agent are joined and then expanded to form a cavity. ing.

[0011]

As a method of cooling a semiconductor element or the like (cooled element) mounted on a printed circuit board by using a heat pipe, for example, a heat pipe is arranged above the mounting surface side of the printed circuit board. Then, there is a method of contacting with a semiconductor element to be cooled. In this case, the heat pipe and the semiconductor element may be brought into contact with each other via heat transfer grease or the like.

However, the number of semiconductor elements mounted on a printed circuit board is not limited to one. There may be a plurality of elements that require cooling, but these semiconductor elements are not necessarily all of the same shape, and the amount of heat generated is usually not constant. Therefore, in the case of a mere flat plate heat pipe, it is necessary to cool them, and it is difficult to bring all of the semiconductor elements into contact with one flat plate heat pipe.

Therefore, a method of preparing a plurality of heat pipes and bringing the heat pipes into contact with each element can be considered. However, in such a method (form), there is a problem in the space around the printed circuit board and a plurality of heat pipes. There are many problems in terms of cost using a heat pipe.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances. The plate-type heat pipe of the present invention is a plate-type heat pipe provided to face a substrate on which a plurality of elements to be cooled are mounted, and the plate-type heat pipe is arranged according to a distance between the element and the element to be cooled. A predetermined convex portion is provided. Further, a plate-type heat pipe provided to face a substrate on which a plurality of elements to be cooled are mounted, wherein a container wall of the plate-type heat pipe on a side opposite to the element to be cooled is opposed to the cooling target. A plate-type heat pipe in a form formed into a convex shape according to the distance from the element may be used.

Further, in the above-mentioned plate type heat pipe,
One or more meshes may be provided inside. In addition, it is preferable that a mesh or a heat transfer metal body is provided in at least a part of the inside of the convex portion along a direction in which the plate-shaped heat pipe and the element to be cooled face each other. The mesh in this case may be in a wound form.

In addition, a support may be provided inside the projection in a direction in which the plate-type heat pipe and the element to be cooled face each other. Instead of the support, or in combination, an embossed portion is provided on the side of the plate-type heat pipe facing the element to be cooled or the container wall on the side facing the element to be cooled,
The embossed portion may be joined to the facing container wall.

The present invention also proposes a cooling structure using a plate-type heat pipe in which the projections of the plate-type heat pipe and the element to be cooled are thermally connected.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a view for explaining a plate type heat pipe of the present invention and a cooling structure using the same.
FIG. 1A is a partial sectional view thereof. On the lower side of the plate-shaped heat pipe 10 in the drawing, elements 20, 21, and 22 to be cooled, such as semiconductor elements, are mounted on a printed circuit board 30 (FIG. 1A). Incidentally, in this example, the number of elements to be cooled is three, but is not limited to this. Reference numeral 23 in the figure denotes the elements to be cooled 20, 21, 22
Is the lead.

The heights of the cooled elements 20, 21, and 22 from the printed circuit board 30 are different from each other. The plate-type heat pipe 10 is provided facing a substrate on which the elements to be cooled 20, 21, and 22 are mounted. The plate-shaped heat pipe 10 has opposing elements to be cooled 20, 21, 22.
A predetermined convex portion 13 is provided in accordance with the distance from. Therefore, even if the cooled elements 20, 21, 22 have different heights, the cooled elements 20, 21, 22 can be brought into thermal contact with one plate-type heat pipe 10.

The elements 20, 21, and 22 to be cooled and the plate-type heat pipe 10 may be in direct contact with each other.
The contact may be made by interposing a heat transfer sheet or heat transfer grease. Alternatively, they may be joined by solder or the like. The heat transmitted from the elements to be cooled 20, 21, 22 to the plate-type heat pipe 10 is generally radiated through the fins 31. In FIG. 1, heat transfer sheets, heat transfer grease, and the like existing between the cooled elements 20, 21, and 22 and the plate-type heat pipe 10 are not shown.

FIG. 1A is a planer heat pipe 10 of FIG.
It is explanatory drawing which shows the assembling situation. The upper plate 110 and the lower plate 111 provided with the convex portions 130, 131, and 132 are joined to assemble the container 11 shown in FIG. The cavity 12 shown in FIG. 1A is formed between the upper plate 110 and the lower plate 111. It is desirable that the upper plate 110, the lower plate 111, and the like constituting the plate-type heat pipe 10 be made of a copper material or an aluminum material having excellent thermal conductivity. Although omitted in FIG. 1A, a working fluid is appropriately accommodated in the hollow portion 12. The working fluid may be selected in consideration of compatibility with the material of the content 11 and the like. For example, water, alternative Freon, florinate, etc. can be applied. Further, the hollow portion 1 is formed so that the phase change of evaporation and condensation of the working fluid is easily performed.
The inside of 2 is cleaned, vacuum degassed, and the like.

The heat of the elements to be cooled 20, 21, and 22 is generally radiated to the outside through the fins 31. As shown in FIG. 3, a fan 310 may be attached to make the heat radiation more efficient. .

FIG. 2 is an explanatory view showing another example of the plate-type heat pipe of the present invention. In the plate-type heat pipe 10 shown in FIG. 1, the hollow portion 12 has a shape almost following the outer shape of the container 11, but as shown in FIG. It may not have a shape that follows.

The plate-type heat pipe shown in FIG. 1 does not have a mesh or the like in its hollow portion 12, but as shown in FIG.
When 0 is arranged, an improvement in performance due to the capillary action can be expected. The mesh usually refers to a mesh-like sheet, but it is preferable that the mesh 40 is appropriately drawn or cut so that the mesh sheet is arranged along the convex portion provided on the lower wall of the container 11 as much as possible. .

In the plate-type heat pipe 10 of FIG. 4, the mesh 40 is provided only on the lower wall side of the container 11, but as shown in FIG. You may. By doing so, the area of the heat radiating portion (condensing portion) as the heat pipe is substantially increased, and further improvement in performance can be expected. In order to hold the mesh 400 on the upper wall side of the container 11, for example, the mesh 400 may be joined to the container 11. As a joining method, a resistance welding method can be easily applied. Alternatively, the mesh sheet may be rolled so that a part of the mesh contacts the upper wall side of the container 11 by the spring force of the mesh itself.

FIG. 6 shows two forms of mesh with the cavity 12.
It shows an example provided inside. In this example, in addition to the mesh 40, a mesh 41 having a shape rising from the projection in the thickness direction of the plate-type heat pipe is provided. As shown in FIG. 7, the mesh 41 is formed by rolling a mesh sheet into a spiral shape. When this mesh 41 is joined to the lower wall or the upper wall of the container 11, the thermal resistance between them is desirably reduced. At this time, the spiral mesh 4
It is preferable to provide a cut or the like at the lower or upper part of 1 to increase the joint area with the lower or upper wall of the container 11.

As described above, the mesh 41 rising from the convex portion in the thickness direction of the plate-type heat pipe is the element having the largest heat flow rate among the elements 20, 21, and 22 to be cooled (in this example, for example, the element to be cooled). It is particularly desirable to provide the element 21 at a portion where the heat flow rate is the largest. This is because the provision of the mesh 41 substantially increases the surface area of the evaporating portion for evaporating the working fluid by receiving the heat of the element to be cooled 21.

FIG. 8A shows a structure in which, in addition to the mesh 52, a heat-transfer metal body 53 having a shape rising from the projection in the thickness direction of the plate-type heat pipe is provided. The shape of the heat transfer metal body 53 is arbitrary, for example, as shown in FIG.
It is preferable that the surface of the heat transfer metal body 53 has an uneven surface as shown in FIG. The heat transfer metal body 53 is preferably joined to the lower and upper walls of the container 50 by brazing, welding, or the like. This heat transfer column 53
Is preferably provided on the convex portion corresponding to the element having the largest heat flow rate among the elements to be cooled. By providing the heat transfer column 53,
The surface area of the evaporation portion is substantially increased.

By the way, in the operation of the plate-type heat pipe, the internal pressure rises due to the evaporation of the working fluid inside. At this time, it tends to swell in the thickness direction of the plate mold. Therefore,
In order to suppress deformation of the container of the plate-type heat pipe due to an increase in the internal pressure, a support 63 as shown in FIG. 9 may be provided. The support 63 is joined to the upper and lower container walls of the plate-shaped heat pipe, and functions as a support for suppressing swelling.

Alternatively, as shown in FIG.
0 is provided with an embossed portion 700 by embossing,
This may be used as a support. These supports 6
3 and the emboss 700 may be used in combination.

FIG. 11 shows a rolled mesh sheet having the function of a column. It should be noted that the mesh 41 in the example of FIG. 6 and the heat transfer metal body 53 in FIG. 8 can also have the function of a support by joining them to the upper and lower container walls.

FIG. 12 is a plan view illustrating an example of a mesh provided in the plate-type heat pipe of the present invention. In the mesh 9 of this example, in addition to the sheet-like mesh sheet 92,
In the vicinity of the center, a spiral mesh 91 that rises toward the front of the figure is cut, and near the upper left and lower right, a cut is made in a part of the sheet-like mesh 92, and the cut is raised to the front of the figure. A mesh rising portion 90 having a bent form is provided.

The above-described plate-type heat pipe of the present invention facilitates thermal connection with a plurality of elements to be cooled, each of which has a different mounting height, and realizes an effective cooling structure with space efficiency and the like. . In addition, by appropriately providing a mesh, elements to be cooled having different heat values can be efficiently cooled. The mesh can also contribute to improving the pressure resistance of the plate-type heat pipe of the present invention. In addition, by appropriately providing the pillars in the plate-type heat pipe of the present invention, the area of the evaporating section can be increased, or the pressure resistance can be increased.

[0034]

As described above, the plate-type heat pipe of the present invention is suitable for cooling a plurality of elements to be cooled, and when the height of the plurality of elements to be cooled is different from each other. Even when the heat velocities of the respective cooled elements are different, these efficient cooling structures can be realized.

[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 an example of a cooling structure using the same. (A) is a partial cross-sectional view, and (A) is a plate-shaped heat pipe 1 of (A).
It is explanatory drawing which shows the assembly situation of No. 0.

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

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

FIG. 5 is an explanatory view showing another example of the plate-type heat pipe according to the present invention and a cooling structure using the same.

FIG. 6 is an explanatory view showing another example of the plate type heat pipe according to the present invention and a cooling structure using the same.

FIG. 7 is an explanatory diagram showing a mesh 41 of FIG. 5;

FIG. 8A is an explanatory view showing another example of the plate-type heat pipe according to the present invention. (A) is the heat transfer column 53 of (A).
FIG.

FIG. 9 is an explanatory view showing another example of the plate-type heat pipe according to the present invention.

FIG. 10 is an explanatory view showing another example of the plate-type heat pipe according to the present invention.

FIG. 11 is an explanatory view showing another example of the plate-type heat pipe according to the present invention.

FIG. 12 is an explanatory view showing an example of a mesh provided inside the plate-type heat pipe of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Plate heat pipe 11 Container 110 Upper plate 111 Lower plate 12 Cavity part 13 Convex part 130, 131, 132 Convex part 133 Convex part 15 Container 16 Cavity part 17 Plate type heat pipe 20, 21, 22 Element to be cooled 23 Lead 30 Printed circuit board 31 Fin 310 Fan 40 Mesh 400 Mesh 41 Mesh 5 Plate heat pipe 50 Container 51 Cavity 52 Mesh 53 Heat transfer metal body 6 Plate heat pipe 60 Container 61 Cavity 62 Mesh 63 Support 7 Plate heat pipe 70 Container 700 Embossed part 71 Hollow part 72 Mesh 8 Plate heat pipe 80 Container 81 Hollow part 82 Mesh 83 Mesh 9 Mesh 90 Mesh rising part 91 Mesh 92 Mesh sheet

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Masanori Ikeda 2-6-1 Marunouchi, Chiyoda-ku, Tokyo Inside Furukawa Electric Co., Ltd.

Claims (8)

[Claims] 1. A plate-type heat pipe provided to face a substrate on which a plurality of elements to be cooled are mounted, wherein the plate-type heat pipe has a predetermined convex portion according to a distance between the element and the element to be cooled. , A plate-type heat pipe. 2. A plate-type heat pipe provided to face a substrate on which a plurality of elements to be cooled are mounted, wherein a container wall of the plate-type heat pipe on a side facing the element to be cooled faces. A plate-shaped heat pipe formed into a convex shape according to a distance from the element to be cooled. 3. A mesh is provided on at least a part of the inside of the projection along a direction in which the plate-shaped heat pipe and the element to be cooled oppose each other.
The plate-shaped heat pipe as described. 4. The plate-type heat pipe according to claim 3, wherein the mesh provided inside the convex portion has a winding form. 5. The plate mold according to claim 1, wherein a heat transfer metal body is provided inside the convex portion in a direction in which the plate heat pipe and the element to be cooled oppose each other. heat pipe. 6. The plate-type heat pipe according to claim 1, wherein a support is provided inside the convex portion in a direction in which the plate-type heat pipe and the element to be cooled face each other. . 7. An embossed portion is provided on a side of the plate-shaped heat pipe facing the element to be cooled or on a side of the container wall facing the element to be cooled, and the embossed portion is joined to the facing container wall. Item 7. A plate-type heat pipe according to any one of Items 1 to 6. 8. The plate-type heat pipe according to claim 1, wherein the projection and the element to be cooled are thermally connected.
Cooling structure using plate heat pipe.