JP2000111281A - Planar heat pipe and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a thin planar heat pipe with a large area at a low cost. SOLUTION: In a planer heat pipe 10 in which closed operating liquid passages 6 are filled with operating liquid L and the steam S of the operating liquid, grooves 5 of deformed section composed of shallow groove parts 3 and deep groove parts 4 are formed on a metallic flat plate 1. The groove forming surface of the metallic flat plate 1 is connected to a metallic flat plate 2 for a cover and the grooves 5 of deformed section are filled with the operating liquid L and the steam S of the operating liquid to form the operating liquid passages 6.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a planar heat pipe and a method of manufacturing the same, and more particularly to a thin, large-area planar heat pipe used for a heat sink for a semiconductor device such as a CPU for a personal computer and the like, and a method of manufacturing the same. It is about the method.

[0002]

2. Description of the Related Art Conventional planar heat pipes include the following.

As shown in FIGS. 14A and 14B,
A sealing portion 72 is provided at one end of the metal tube, and a working fluid filling nozzle 7 is provided at the other end.
After forming a cylindrical heat pipe having a flat heat pipe 71, a flat heat pipe 71 is formed by pressing or the like so that a part of the outer wall surface of the pipe becomes a parallel plane. Books (6 in FIG. 14)
A planar heat pipe formed by joining the heat collecting plates 74 side by side.

As shown in FIGS. 15A and 15B,
The flat porous tube 81 is extruded using aluminum (or an aluminum alloy) which is easy to process, and a sealing material 82 is provided at one end of the flat porous tube 81 and a working fluid sealing nozzle 84 is provided at the other end via a header member 83. A flat heat pipe attached.

As shown in FIGS. 16A and 16B,
Using a container material 94 having a meandering channel 91 made of a material such as aluminum or copper using a roll bonding method,
A planar heat pipe in which one end of a meandering flow path 91 is sealed with a sealing material 92 and a working liquid sealing nozzle 93 is attached to the other end.

[0006]

However, the above-mentioned flat heat pipes have the following problems.

The flat heat pipe 71 has an aspect ratio (width / thickness) of the flat heat pipe 71 from the relationship between the vapor pressure of the working fluid and the strength of the flat wall of the flat heat pipe 71.
Therefore, only a narrow flat heat pipe 71 can be manufactured, and when a large-area planar heat pipe is to be manufactured, a large number of flat heat pipes 71 must be used. . In most industrial applications, at least one surface of the flat heat pipe needs to be smooth. However, even if many flat heat pipes 71 are arranged, a smooth surface cannot be obtained. It has to be joined to the heat plate 74), which causes a problem that the production cost of the flat heat pipe is increased.

The flat heat pipe has a limitation on the minimum thickness and the maximum width of the collectible heat pipe 81 that can be produced due to the restriction of the extrusion processing apparatus, and also requires time and effort to process the end of the collective heat pipe 81. However, there has been a problem that the production cost rises.

[0009] The flat heat pipe has been put to practical use as a soaking material for refrigerators using aluminum as a material.
Since it is difficult to form a thin working liquid flow path as the meandering flow path 91, the thickness of the container material 94 is increased, which is not suitable for cooling a small member such as a semiconductor element. In addition, the meandering channel 91
Has a disadvantage that the wicking force is small due to the smooth inner surface, and operation in the horizontal state to the top heat state cannot be expected. Here, a similar heat pipe made of copper is also manufactured, but is also not suitable for cooling a semiconductor element because of its large size and weight.

Accordingly, an object of the present invention is to solve the above-mentioned problems and provide a method for manufacturing a thin, large-area planar heat pipe at low cost.

[0011]

According to a first aspect of the present invention, there is provided a flat heat pipe filled with a working fluid and a working fluid vapor in a closed working fluid flow path. A deformed cross-sectional groove consisting of a shallow groove portion and a deep groove portion is formed on a flat plate, and the groove forming surface of the metal flat plate is joined to the cover metal flat plate, and the above-mentioned deformed cross-sectional groove is filled with the working fluid and the vapor of the working fluid. The working fluid flow path.

According to a second aspect of the present invention, there is provided the planar heat pipe according to the first aspect, wherein a plurality of the irregular cross-sectional grooves are not formed in communication with an end face of the flat metal plate, and a plurality of the grooves are formed.

According to a third aspect of the present invention, the deep groove portion of the irregularly shaped cross-sectional groove is a vapor flow path for flowing the vapor of the working fluid, and the shallow groove portion is a liquid flow path for flowing the working fluid. A planar heat pipe according to claim 1 or 2.

According to the above configuration, it is possible to obtain a thin, large-area planar heat pipe having a large wicking force, that is, having a working fluid flow path having a capillary action. Further, this planar heat pipe does not require a specific working fluid sealing portion.

According to a fourth aspect of the present invention, there is provided a flat heat pipe according to the second or third aspect, wherein the metal flat plate is formed with a connection groove for connecting the above-mentioned grooves having different shapes.

According to the above configuration, the temperature distribution of the planar heat pipe is further reduced.

According to a fifth aspect of the present invention, there is provided a method for manufacturing a flat heat pipe filled with a working fluid and a vapor of the working fluid in a closed working fluid flow path, wherein the irregularly shaped groove having a shallow groove portion and a deep groove portion is provided. The groove forming surface of the formed flat metal plate and the flat metal plate for the cover are opposed to each other at a predetermined interval, and then, in a working fluid vapor atmosphere of a predetermined density, the temperature of both metal flat plates is equal to or higher than the saturation temperature of the working fluid vapor. While maintaining the temperature, the two metal flat plates are brought close to and in contact with each other, and the joining surfaces are joined together metallically to form the working fluid flow path and simultaneously fill the working fluid flow path with the working fluid and the working fluid vapor. Is what you do.

According to a sixth aspect of the present invention, a joining metal layer is uniformly formed in advance on opposite surfaces of the two metal flat plates, and a joining metal projection is formed on at least one of the surfaces. 6. The method for manufacturing a planar heat pipe according to claim 5, wherein said gap is formed by forming or by interposing metal particles for bonding between said layers.

According to a seventh aspect of the present invention, the two metal plates are opposed to each other while maintaining the distance therebetween, and a pressure is applied in a direction in which the two metal plates approach each other, and the two metal plates are joined in a saturated atmosphere of a working liquid vapor having a predetermined density. The method for manufacturing a flat heat pipe according to claim 5 or 6, wherein the joining surface is metallically joined by heating to a temperature not lower than the melting point to melt the joining metal.

According to an eighth aspect of the present invention, the two metal flat plates are opposed to each other while maintaining the distance therebetween, and pressure is applied in a direction in which the two metal flat plates approach to each other, and ultrasonic waves are applied to the two metal flat plates in a saturated atmosphere of a working liquid vapor having a predetermined density. The method according to claim 5 or 6, wherein the joining surface is metallically joined.

According to the above-described manufacturing method, a thin, large-area planar heat pipe having a working fluid flow path having a capillary action can be manufactured easily and at low cost.

[0022]

Embodiments of the present invention will be described below.

As shown in FIG. 13, in a heat pipe having a fine working fluid flow path 61 having a triangular cross section, a capillary phenomenon occurs near each apex of the working fluid flow path 61 and the working fluid flow path 6
The vicinity of each vertex of 1 becomes a liquid flow path 62 through which the working liquid L flows, and the central part of the working liquid flow path 61 becomes a steam flow path 63 through which the working liquid vapor S flows, and can be operated as a heat pipe. Such a heat pipe has been proposed by Grover and is generally known as a "micro heat pipe".

The present inventors have made use of the principle of operation of this micro heat pipe to arrive at the invention of a planar heat pipe having a capillary action and in which a liquid flow path and a vapor flow path are clearly separated. .

FIG. 1 shows a cross-sectional view of the planar heat pipe of the present invention, and FIGS. 3 to 6 show examples of top views of the planar heat pipe of the present invention. Here, FIG.
It is a principal part enlarged view of (a).

As shown in FIGS. 1 (a) and 1 (b), a flat heat pipe 10 of the present invention has a flat metal plate 1 having a smooth surface.
A grooved surface 5 having a shallow groove portion 3 and a deep groove portion 4 is formed on one surface thereof, and a cover plate (metal plate for cover) 2 having a smooth surface is joined to the groove forming surface of the metal plate 1 to form a groove having a deformed cross section. The closed space formed by the cover 5 and the cover plate 2 is a working fluid flow path 6 for filling the working fluid L and the working fluid vapor S.

As a constituent material of the metal flat plate 1 and the cover plate 2, for example, copper and the like can be cited, but there is no particular limitation.

The modified cross-sectional groove 5 is formed so as not to communicate with the end face of the metal flat plate 1, that is, so that a part of the modified cross-sectional groove 5 does not face the end face of the metal flat plate 1.
The number of the grooves is arbitrary (five in FIG. 1A). The space formed by the deep groove portion 4 of the modified cross-sectional groove 5 and the cover plate 2 serves as a steam flow path for flowing the working fluid vapor S, and the space surrounded by the shallow groove portion 3 and the cover plate 2 stores the working fluid L. It becomes a liquid flow path for flowing. In addition, the method of forming the irregular cross-sectional groove 5 is not particularly limited.

Further, each of the modified cross-sectional grooves 5 is connected by a modified cross-section connecting groove (not shown), and as shown in FIG. The channel 8 may be used.

Further, at least one shallow groove portion 3 of the modified cross-sectional groove 5 may be provided along the longitudinal direction of the deep groove portion 4, and the cross-sectional shapes of the shallow groove portion 3 and the deep groove portion 4 are not particularly limited. .

Further, the working fluid flow path 6 (irregular sectional groove 5)
May be linear, curved linear, concentric, or radial as shown in FIGS. 3 to 6, and is not particularly limited.

That is, the planar heat pipe 1 of the present invention
According to No. 0, the closed space formed by the irregular cross-sectional groove 5 formed in the metal flat plate 1 and the cover plate 2 is used as the working fluid flow path 6, so that the wicking force is large, and the thin and large-area flat heat You can get a pipe.

The hydraulic fluid L sealed in the hydraulic fluid flow path 6
Since the working fluid vapor S is simultaneously sealed when the working fluid flow path 6 is formed, it is not necessary to provide a specific working fluid sealing portion in the working fluid flow path 6.

Furthermore, even though the respective working fluid passages 6 are independent of each other, the temperature distribution in the plane of the planar heat pipe 10 is small, but the respective working fluid passages 6 are connected by the connection passages 7. The temperature distribution can be further reduced by forming the integrated hydraulic fluid channel 8.

Furthermore, the flat heat pipe 1 of the present invention
After the production of No. 0, the flat heat pipe 10 can be subjected to bending or boring.

Next, an apparatus used for manufacturing the flat heat pipe of the present invention will be described.

FIG. 9 is a schematic view showing an example of a flat heat pipe manufacturing apparatus of the present invention, and FIG. 10 is a partially enlarged view of FIG.
Shown in

As shown in FIGS. 9 and 10, the apparatus for manufacturing a flat heat pipe according to the present invention comprises an upper heating / cooling plate 2
1, a lower heating / cooling plate 22 provided opposite to the upper heating / cooling plate 21, and an entire upper heating / cooling plate 22, and a lower heating / cooling plate 2
It mainly comprises an inverted deep dish-shaped upper structure 25 detachably mounted on the upper surface 2 and a pressurizing device 26 provided integrally with the upper structure 25. Here, the upper structure 2
A space surrounded by the lower heating / cooling plate 22 and the lower heating / cooling plate 22 forms a chamber 27.

The upper heating / cooling plate 21 is supported by the upper structure 25 via a bellows 28, and is provided to be vertically movable. Heat medium circulation channels 23 and 2 are provided in the upper heating / cooling plate 21 and the lower heating / cooling plate 22.
4 are formed.

A bellows 30a is provided at one end of the heat medium circulation passage 23.
The heat medium pipe 30 and the heat medium supply line 33a provided with
A heat medium supply line 33b is connected to one end of the heat medium circulation passage 24, and the heat medium supply lines 33a and 33b are integrated into one heat medium supply line 33 on the way. One end of a low-temperature heating medium supply line 34 and one end of a high-temperature heating medium supply line 35 are connected to the integrated heating medium supply line 33. The other end of the low-temperature heat medium supply line 34 is a low-temperature heat medium N
_The low-temperature heating medium tank filled with _L is connected, and the other end of the high-temperature heating medium supply line 35 is connected to the high-temperature heating medium tank 32 filled with the high-temperature heating medium _NH .

Here, the low-temperature heating medium supply line 34 and the high-temperature heating medium supply line 35 are provided with a pump and a valve, respectively. The low-temperature heat medium tank 31 includes a heater and a cooling unit (for example, a cooling coil), and the high-temperature heat medium tank 32 includes a heater.

At the other end of the heat medium circulation channel 23, a heat medium pipe 36 having a bellows 36a and a heat medium recovery line 37
a is a heat medium recovery line 37 at the other end of the heat medium circulation flow path 24.
b is connected, and the heat medium recovery lines 37a and 37b are integrated into one heat medium recovery line 37 on the way. One end of a low-temperature heat medium recovery line 38 and one end of a high-temperature heat medium recovery line 39 are connected to the heat medium recovery line 37 via a switching valve. The other end of the low-temperature heat medium recovery line 38 is connected to the low-temperature heat medium tank 31, and the other end of the high-temperature heat medium recovery line 39 is connected to the high-temperature heat medium tank 32.

The lower heating / cooling plate 22 has a supply hole 41 and an exhaust hole 42 whose one end faces the chamber 27.

The other end of the supply hole 41 is connected to a working fluid supply line 44.
The working fluid supply line 44 is connected to the working fluid tank 43. The other end of the exhaust hole 42 is connected to an exhaust line 45, and the exhaust line 45 branches from the middle into three lines: a vacuum line 46, a hydraulic fluid recovery line 48, and an atmosphere release line 50. . A vacuum pump 47 is provided in the evacuation line 46, and a hydraulic fluid recovery line 48 is connected to a hydraulic fluid recovery tank 49.

Here, a valve is provided for each of the working fluid supply line 44, the evacuation line 46, the working fluid recovery line 48, and the atmosphere release line 50.

Next, the manufacturing method of the present invention will be described.

A cover plate (for example, a metal copper plate) 2 faces a groove forming surface of a metal flat plate (for example, a metal copper plate) 1 having a modified cross-sectional groove 5 formed on one side thereof.

More specifically, as shown in FIG. 10, soldering is performed in advance on a portion of the metal plate 1 to be joined except for the deformed cross-sectional groove 5 and on the entire surface of the cover plate 2 facing the metal plate 1. (For example, Sn-3.5Ag solder) or the like, and a bonding metal layer 51 is formed by means of plating or the like.
In a state where spacers 52 made of particles (or protrusions) of a joining metal material are appropriately arranged between both surfaces, the spacers 52 are sandwiched between the upper heating / cooling plate 21 and the lower heating / cooling plate 22 and set in the chamber 27. .

Here, the low-temperature heat medium (approximately 40) is supplied from the low-temperature heat medium tank 31 and the high-temperature heat medium tank 32 to the heat medium circulation passages 23 and 24 of the heating / cooling plates 21 and 22 via the respective lines.
0K (127 ° C)) N _L and high-temperature heat carrier (about 520K
(247 ° C.)) By circulating and supplying _NH , the temperature of both the heating and cooling plates 21 and 22 can be adjusted. At this time, the low-temperature heat medium _NL is circulated through the heat medium circulation passages 23 and 24. The heating and cooling plates 21 and 22 are supplied and the temperature of the working fluid vapor (for example, Freon R-114) S is filled (about 400 ° C.).
K).

Next, the valve of the vacuum line 46 is opened, and the vacuum pump 47 is operated to evacuate the inside of the chamber 27 through the exhaust hole 42. Then, vacuum line 4
After closing the valve of No. 6, the valve of the working fluid supply line 44 is opened, and the working fluid vapor S having a predetermined density is injected into the chamber 27 through the supply hole 41. afterwards,
After the inside of the chamber 27 is saturated with the working fluid vapor S, the valve of the working fluid supply line 44 is closed.

Next, the heat medium circulating and supplied to the heat medium circulation channels 23 and 24 is switched from the low-temperature heat medium _NL to the high-temperature heat medium _NH .
The temperature of the two heating / cooling plates 21 and 22 is raised to the melting temperature of the joining metal (about 520 K), and the upper heating / cooling plate 21 is pressed in the direction of the lower heating / cooling plate 22 so that the metal flat plate 1 is pressed. Then, the cover plate 2 is pressed to melt the joining metal layer 51 and the spacer 52 on the joining surface of the two plates 1 and 2. Thereby, the joining surfaces of the two plates 1 and 2 are tightly joined to form the respective working fluid passages 6 inside the two plates 1 and 2, and the working fluid vapor S is formed in the respective working fluid passages 6. You are trapped.

Thereafter, the heat medium circulated to the heat medium circulation channels 23 and 24 is switched from the high-temperature heat medium _NH to the low-temperature heat medium _NL , and the heating / cooling plates 21 and 22 are cooled and melted. The flattened heat pipe 10 is obtained by solidifying the joined metal. As a result, each of the working fluid passages 6 sealed inside the plates 1 and 2 is formed. The hydraulic fluid vapor S sealed in each hydraulic fluid flow path 6 condenses into a hydraulic fluid L and a hydraulic fluid vapor S.

Next, the valve of the hydraulic fluid recovery line 48 is opened, and the hydraulic fluid vapor S is supplied to the hydraulic fluid recovery tank 49 through the exhaust hole 42, the exhaust line 45, and the hydraulic fluid recovery line 48.
To be collected. At this time, the hydraulic fluid vapor S is cooled by the cooling means in the hydraulic fluid recovery tank 49, collected as the hydraulic fluid L, and reused in the hydraulic fluid tank 43.

Next, after closing the valve of the working fluid recovery line 48, the valve of the atmosphere release line 50 is opened to inject the atmosphere (outside air) into the chamber 27.

Finally, the upper structure 25 and the upper heating / cooling plate 21 are removed, and the flat heat pipe 10 is taken out.

Here, the encapsulation rate of the working fluid L in the working fluid flow path 6 (the ratio of the volume of the working fluid L to the total volume of the working fluid flow path 6) depends on the working fluid L when the heat pipe 10 is formed. It can be easily adjusted by the vapor density (temperature function) of L. FIG. 7 shows the relationship between the liquid and vapor densities ρ ′, ρ ″ and the temperature and the relationship between the pressure and the temperature in the saturated state of the Freon R-114 used as the working liquid L of the planar heat pipe 10 of the present invention.

As shown in FIG. 7, both heating / cooling plates 21 and
Assuming that the density of the saturated liquid when the temperature of the sample 22 is the normal temperature T ₁ is ρ ₁ ′, and the density of the saturated vapor when the temperatures of the heating and cooling plates 21 and 22 are raised to T ₂ is ρ ₂ ″, the density After the working fluid vapor S of ρ ₂ ″ is sealed in the working fluid flow path 6, the entire temperature is reduced to T
When cooling to _1, most of the hydraulic fluid steam S of the working fluid flow path 6 is the working fluid L and the saturated hydraulic fluid steam S of the density [rho ₁ "of the density [rho ₁ 'condensed. Therefore, hydraulic fluid The enclosing rate of the working fluid L in the flow path 6 is as follows: ψ (%) = (ρ ₂ ″ / ρ ₁ ′) × 100

FIG. 8 shows the relationship between the working fluid filling rate and the temperature.

In a normal heat pipe, the working fluid L
Is about 10 to 30%, for example, T
₁ 300K (27 ° C.), when 15% of [psi, as shown in FIG. 8, enclosed temperature T ₂ of the hydraulic fluid steam S is about 400K
(127 ° C.). At this time, the vapor pressure of the working fluid vapor S is about 2.4M as shown in FIG.
Pa and relatively low pressure.

The metal joining of the two plates 1 and 2 needs to be performed at a temperature lower than the decomposition temperature of the working fluid L. When copper is used as the material of the two plates 1 and 2, the metal joining method of the two plates 1 and 2 is as follows. Soldering method (for example, Sn-3.5Ag or Sn-35P
b), a Sn diffusion bonding method using pure Sn, an ultrasonic pressure welding method, or a combination thereof (for example, an ultrasonic pressure welding method with a bonding metal interposed) can be used. .

As the working fluid L, chlorofluorocarbon, perfluorocarbon, methanol or the like can be used.

In the method of manufacturing a flat heat pipe of the present invention, copper is used as a material for the metal flat plate 1 and the cover plate 2, and Sn-3.5Ag is used as a material for the bonding metal layer 51 and the spacer 52. Although CFC R-114 is used as the working fluid L as the solder, the combination is not particularly limited. The working fluid L is not thermally decomposed at the joining temperature of the two plates 1 and 2, Can be joined air-tight over a wide range, there is no generation of non-condensable gas or corrosion during use as the planar heat pipe 10, and the vapor pressure of the working fluid vapor S in the operating temperature range of the planar heat pipe 10 is high. Any combination that satisfies conditions such as the non-flammability of the working fluid L may be used.

That is, according to the method for manufacturing a planar heat pipe of the present invention, the formation of the working fluid flow path 6 and the working fluid flow path 6
Since the working fluid L and the working fluid vapor S are simultaneously sealed in the inside, the manufacturing process is simplified, and the manufacturing cost can be reduced.

When the maximum value of the operating temperature of the flat heat pipe 10 is 373 K (100 ° C.), Freon R-
The saturated vapor pressure of 114 is about 1.5, as shown in FIG.
Since the pressure is MPa, the thickness of the cover plate 2 can be reduced by reducing the width of the working liquid flow path 6, and the thickness of the planar heat pipe 10 can be reduced.

Further, at the time when the working fluid vapor S is sealed, there is almost no pressure difference between the inside and outside of each working fluid flow path 6 (the flow of the working fluid vapor S is not generated). Does not affect.

Further, the working fluid vapor S in the vicinity of the joint surface between the two plates 1 and 2 has the joining temperature of the working fluid vapor S
Is higher than the saturation temperature of the substrate, and is in a “dry steam” state.
, It does not adversely affect metal bonding.

Next, another embodiment of the present invention will be described.

FIG. 2 shows a cross-sectional view of a planar heat pipe according to another embodiment. The same members as those in FIG. 1 are denoted by the same reference numerals.

The flat heat pipe 10 of the present invention is shown in FIG.
As shown in FIG. 5, a metal plate 1 having a smooth surface was formed with a modified cross-sectional groove 5 consisting of a shallow groove 3 and a deep groove 4 on one surface.

On the other hand, as shown in FIG. 2, the flat heat pipe 11 according to the present embodiment has a deformed cross-sectional groove 5 comprising a shallow groove 3 and a deep groove 4 on both sides of a flat metal plate 1 having a smooth surface. Are formed on both sides of the metal flat plate 1, and the lid plates 2a and 2b having smooth surfaces are joined to each other, and the irregularly shaped groove 5 and the lid plates 2a and 2b are formed.
The space enclosed by is defined as a working fluid flow path 6 for enclosing a working fluid (not shown) and a working fluid vapor (not shown).

It is needless to say that the flat heat pipe 11 of the present embodiment also exerts the same effect as the flat heat pipe 10 of the present invention, and a new heat transfer capability (heat dispersibility) is further improved. It is effective.

[0072]

[Example] Length 150mm, width 50mm, thickness 1.1m
At m, a deformed cross-section groove having a convex cross-section is formed on one surface of a metal flat plate made of a hard copper plate, and a joining metal layer is formed using Sn-3.5Ag solder at portions other than the deformed cross-section groove portion of the groove forming surface. . In addition, the length of 150 mm, the width of 50 mm, the thickness of 0.4 mm, S over the entire joining surface of the lid plate made of a hard copper plate
A bonding metal layer is formed using n-3.5Ag solder.

A spacer having a diameter of 1 mm and made of Sn-3.5Ag solder particles was interposed between the groove forming surface of the metal flat plate and the joining metal layer forming surface of the lid plate, and the flat surface shown in FIG. Both heating and cooling plates 21 and 2 of the heat pipe manufacturing apparatus
Set between two.

Thereafter, the flat heat pipe producing apparatus having a length of 150 mm, a width of 50 mm and a thickness of about 1.5 mm was operated by using the fluorocarbon R-114 as a working fluid and operating the flat heat pipe manufacturing apparatus in the above-described procedure. Make it.

The flat heat pipe manufactured in this manner is subjected to bending to obtain a curved heat pipe 55 as shown in FIGS. 11 (a) and 11 (b). A circuit board (not shown) is formed at one end of the curved heat pipe 55 on the side of the lid plate 2.

Thereafter, as shown in FIGS. 12A and 12B, a circuit board (not shown) formed on one end (left side in FIG. 12) of the curved heat pipe 55 on the side of the cover plate 2. A plurality of semiconductor elements 56 having different calorific values are mounted thereon, and a cooling device (for example, a radiation fin) 57 is provided on the other end side (right side in FIG. 12) to manufacture a semiconductor module 58.

This semiconductor module 58 has a curved heat pipe 55 although the heat radiation amount of each semiconductor element 56 is different.
By the action of each working fluid flow path (not shown) formed inside, the entire body can be kept at a substantially uniform temperature by equalizing the temperature. In addition, since the curved heat pipe 55 can be formed with a through hole or a screw hole between the respective working liquid flow paths, each semiconductor element 56 and the cooling device 57 can be easily fixed.

[0078]

In summary, according to the present invention, the following excellent effects are exhibited.

(1) Since the working fluid flow path is a closed space formed by the irregular cross-sectional groove formed in the metal flat plate and the cover plate, a wicking force is large, a thin, large-area planar heat pipe is obtained. be able to.

(2) Since the formation of the working fluid flow path and the sealing of the working fluid and the working fluid vapor into the working fluid flow path are performed simultaneously, the manufacturing process is simplified and the manufacturing cost can be reduced. .

[Brief description of the drawings]

FIG. 1A is a cross-sectional view of a planar heat pipe of the present invention, and FIG. 1B is an enlarged view of a main part of FIG. 1A.

FIG. 2 is a cross-sectional view of a planar heat pipe according to another embodiment.

FIG. 3 is an example of a top view of the planar heat pipe of the present invention.

FIG. 4 is an example of a top view of the planar heat pipe of the present invention.

FIG. 5 is an example of a top view of the planar heat pipe of the present invention.

FIG. 6 is an example of a top view of the planar heat pipe of the present invention.

FIG. 7 is a diagram showing the relationship between the density of liquid and vapor ρ ′, ρ ″ and temperature and the relationship between pressure and temperature in the saturated state of Freon R-114 used as the working fluid of the planar heat pipe of the present invention.

FIG. 8 is a diagram showing the relationship between the working fluid filling rate and temperature.

FIG. 9 is a schematic view showing an example of the apparatus for manufacturing a planar heat pipe of the present invention.

FIG. 10 is a partially enlarged view of FIG. 9;

FIG. 11 (a) is a front view of a flat heat pipe of the present invention obtained by bending the heat pipe.
FIG. 12B is a view as seen in the direction of arrow D in FIG.

FIG. 12A is a top view of a semiconductor device or the like mounted on the curved heat pipe of FIG. 11;
FIG. 12B is a view as seen in the direction of arrow E in FIG.

FIG. 13 is a cross-sectional view of the micro heat pipe.

14 (a) is a top view of a conventional planar heat pipe, and FIG. 14 (b) is a sectional view taken on line A- of FIG. 14 (a).
FIG. 3 is a sectional view taken along line A.

FIG. 15 (a) is a top view of a conventional planar heat pipe, and FIG. 15 (b) is a sectional view taken along line B- of FIG. 15 (a).
It is a B sectional view.

FIG. 16 (a) is a top view of a conventional planar heat pipe, and FIG. 16 (b) is a sectional view taken along line CC of FIG. 16 (a).
It is a line sectional view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Metal flat plate 2 Cover plate (cover metal flat plate) 3 Shallow groove part 4 Deep groove part 5 Irregular cross-section groove 6 Working fluid channel 10, 11 Planar heat pipe 51 Joining metal layer (joining metal layer) 52 Spacer (projection or Particles) L Hydraulic fluid S Hydraulic fluid vapor (Hydraulic fluid vapor)

Claims (8)

[Claims] 1. A flat heat pipe filled with a working fluid and a vapor of the working fluid in a closed working fluid flow path, wherein a deformed cross-sectional groove including a shallow groove portion and a deep groove portion is formed in a metal flat plate.
A flat heat, wherein the groove forming surface of the metal flat plate and the cover metal flat plate are joined together, and the working fluid and the vapor of the working fluid are sealed in the irregular cross-sectional groove to form the working fluid flow path. pipe. 2. The flat heat pipe according to claim 1, wherein a plurality of said irregular cross-sectional grooves are not formed in communication with an end face of said flat metal plate, and a plurality of said grooves are formed. 3. The method according to claim 1, wherein the deep groove portion of the irregular cross-sectional groove is a vapor flow path for flowing the vapor of the working fluid, and the shallow groove portion is a liquid flow path for flowing the working fluid. Item 2. A planar heat pipe according to item 2. 4. The metal flat plate is formed with an irregular cross-section connecting groove for connecting the respective irregular cross-sectional grooves to each other.
Or the planar heat pipe according to claim 3. 5. A method of manufacturing a flat heat pipe filled with a working fluid and a vapor of the working fluid in a closed working fluid flow path, wherein a flat metal plate having a deformed cross-sectional groove including a shallow groove and a deep groove is formed. The groove forming surface and the cover metal flat plate are opposed to each other at a predetermined interval, and then the temperature of both metal flat plates is maintained at a temperature equal to or higher than the saturation temperature of the hydraulic liquid vapor in a hydraulic liquid vapor atmosphere of a predetermined density. The two metal flat plates are brought close to and in contact with each other, and the joining surfaces are metallically joined to simultaneously form the working fluid flow path and enclose the working fluid and the working fluid vapor in the working fluid flow path. Of manufacturing a flat heat pipe. 6. A method according to claim 1, wherein said two metal flat plates have opposite surfaces.
The bonding metal layer is formed uniformly, and the bonding metal protrusion is formed on at least one of the surfaces, or the bonding metal particles are interposed between the layers to provide the spacing. A method for manufacturing a planar heat pipe according to claim 5. 7. A pressure is applied in a direction in which the two metal plates approach each other while maintaining the above-mentioned interval, and the two metal plates are brought to a temperature higher than the melting point of the joining metal in a saturated atmosphere of a working liquid vapor having a predetermined density. The heating is performed to melt the joining metal and to join the joining surface metallically.
The manufacturing method of the planar heat pipe of the description. 8. A pressure is applied in a direction in which the two metal flat plates approach each other while maintaining the above-mentioned interval, and ultrasonic waves are applied to the two metal flat plates in a saturated atmosphere of a working liquid vapor of a predetermined density to thereby form the bonding surface. The method for producing a planar heat pipe according to claim 5 or 6, wherein the metal is joined metallically.