US20100108297A1

US20100108297A1 - Heat Pipe and Making Method Thereof

Info

Publication number: US20100108297A1
Application number: US12/596,490
Authority: US
Inventors: Jen-Shyan Chen
Original assignee: NeoBulb Technologies Inc
Current assignee: NeoBulb Technologies Inc
Priority date: 2007-04-28
Filing date: 2007-04-28
Publication date: 2010-05-06
Also published as: WO2008131587A1

Abstract

A heat pipe and the method thereof are provided. The heat pipe (1) comprises a pipe body (12), a cavity (14) and a porous capillary diversion layer (18). The pipe body (12) has a first open (122) and a third open (124), and the cavity (14) has a second open (142). The first open (122) and the second open (142) are bonded together, and the third open (124) is sealed to form the heat pipe (1). The heat pipe comprises working liquid in it. The sectional area of the cavity (14) is larger than that of the pipe body (12). And the cavity (14) has a planar end (144).

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention generally relates to a heat pipe and making method thereof, and more particularly, to a heat pipe applied to a light emitting diode (LED) for heat dissipating and making method thereof
2. Description of the Prior Art
With the vigorous development of technology, many electrical products have unsolved heat-dissipating problems. For example, when the central processing unit (CPU) of the computer operates, it will generate a lot of heat. Once the heat can not be removed, the operation of the system will be seriously affected. The heat pipe plays important role in the heat-dissipating part of the CPU of the computer. Especially, when the usage space of the electrical apparatus gradually becomes smaller, the heat-dissipating device which can efficiently dissipate heat and fully use the space to dissipate heat becomes more important.
The conventional heat pipe heat-dissipating is always using a metallic block material, wherein a heat plane is formed on the metallic block material by staggering a plurality of heat pipes. However, the heat generated by the electric component located upon the heat plane needs to be transmitted to the heat pipes indirectly through the metallic block material, therefore, the heat-dissipating efficiency of this heat-dissipating mechanism will be limited to the physical property of the metallic block material, and difficult to be improved. If the electric component is directly located on the heat pipe (since the diameter of the heat pipe is limited in a general electric apparatus), the heat pipe can not load a larger electric component or a group of electric components. Using the vapor chamber can directly solve the narrow deposing area problem, however, extra device is needed to dissipate the heat from the electric component, such as a heat-dissipating fin. And, the deposing space needed for the above-mentioned vapor chamber and its heat-dissipating fin is still too larger to the electric apparatus only having a smaller space.
Accordingly, the invention is to provide a heat pipe having different cross-section areas and making method thereof to provide an effective and rapid heat-dissipating mechanism for the electric component with larger heat area or a group of electric components to solve the problems mentioned above.

SUMMARY OF THE INVENTION

A scope of the present invention is to provide a heat pipe and making method thereof.
Another scope of the present invention is to provide a heat pipe having different cross-section areas applied to a light emitting diode (LED) for heat dissipating and making method thereof.
The heat pipe of the invention is applied to a light emitting diode (LED) for heat dissipating. The heat pipe comprises a tube, a chamber, and a porous capillary diversion layer. The tube has a first open, and the diameter of the tube is smaller than 10 mm. The chamber has a second open, and the second open and the first open are tight joined together to form a sealed space via the tube and the chamber. The porous capillary diversion layer is formed in the tube and the chamber. Wherein, the sealed space contains a working fluid, and a cross-section area of the chamber is larger than a cross-section area of the tube.
In an embodiment, the tube and the chamber are formed in one piece. In another embodiment, the chamber is formed by a concave and an upper cover. The upper cover is engaged with the concave and the upper cover has the second open. The concave can be made through a process of powder metallurgy, stamping, injection molding, casting, or machining. In an embodiment, the chamber has a flat end for deposing a general electric component.
In an embodiment, the porous capillary diversion layer is made by sintering a copper powder, a nickel powder, a silver powder, a metallic powder plated with copper, nickel, silver, or other similar metallic powders.
In another embodiment, the porous capillary diversion layer comprises a metallic pellet layer and a metallic net body. The metallic pellet layer is formed on the inner wall of the tube and the inner wall of the chamber by sintering, and the metallic net body is disposed upon the metallic pellet layer.
In another embodiment, the porous capillary diversion layer comprises a wavy carped metal cloth and a flat metal net fabric layer. Besides, the wavy carped metal cloth is spread on the inner wall of the tube and the inner wall of the chamber, and the flat metal net fabric layer is disposed on the wavy carped metal cloth, wherein the wavy carped of the wavy carped metal cloth is in a form of triangle, rectangle, trapezium, or wave.
In another embodiment, the porous capillary diversion layer comprises a plurality of tiny notches formed on the inner wall of the tube and the inner wall of the chamber.
In another embodiment, the porous capillary diversion layer comprises a plurality of tiny notches and a metallic sintered layer, the tiny notches are formed on the inner wall of the chamber, and the metallic sintered layer is formed on the inner wall of the tube and the metallic sintered layer is welded with the tiny notches.
The heat pipe making method of the invention comprises the steps of: (a) providing a tube having a first open and a third open; (b) providing a chamber having a second open; (c) tightly joining the first open of the tube and the second open of the chamber together to form a semi-finished heat pipe; (d) vacuuming the semi-finished heat pipe; and (e) sealing the third open. Wherein the inner wall of the semi-finished heat pipe comprises a porous capillary diversion layer; the semi-finished heat pipe contains a working fluid; the cross-section area of the chamber is larger than the cross-section area of the tube. And, the working fluid is poured into the semi-finished heat pipe before or after step (d) is performed. Additionally, in the step (c), the tight joining is performed through a process of welding, soldering, machine fastening, or gluing.
The step (b) of the heat pipe making method of the invention can comprise the steps of: providing a concave; providing an upper cover having the second open; and engaging the upper cover and the concave to form the chamber. The concave can be made through a process of powder metallurgy, stamping, injection molding, casting, or machining. And, a first sintered metal layer can be formed on the concave, a second sintered metal layer can be formed on the upper cover, and the first sintered metal layer is engaged with the second sintered metal layer. Or, a plurality of first tiny notches is formed on the concave, a plurality of second tiny notches is formed on the upper cover, and the plurality of first tiny notches is engaged with the plurality second of tiny notches. Then, the porous capillary diversion layer is formed when the concave and the tube are engaged.
In an embodiment, a sintered metallic powder layer is formed on the inner wall of the chamber. The porous capillary diversion layer is formed by the following steps of: interposing a center pillar into the semi-finished heat pipe from the third open and the center pillar is approximately tightly against the sintered metallic powder layer; filling a first metallic powder between the center pillar and the semi-finished heat pipe; performing a sintering process to make the first metallic powder and the metallic powder mutually welded to form the porous capillary diversion layer; and getting the center pillar out of the semi-finished heat pipe.
In another embodiment, the inner wall of the chamber has a plurality of tiny notches. The porous capillary diversion layer is formed by the following steps of: interposing a center pillar into the semi-finished heat pipe from the third open and the center pillar is approximately tightly against the plurality of tiny notches; filling a second metallic powder between the center pillar and the semi-finished heat pipe;
performing a sintering process to make the second metallic powder and the plurality of tiny notches mutually welded to form the porous capillary diversion layer; and getting the center pillar from the semi-finished heat pipe. By the way, in the two above-mentioned embodiments, the first metallic powder or the second metallic powder is a copper powder, a nickel powder, a silver powder, a metallic powder plated with copper, nickel, silver metal powder, or other metallic powders.
In another embodiment, a machining process is used to make the plurality of tiny notches on the inner wall of the tube and the inner wall of the chamber to form the porous capillary diversion layer.
In another embodiment, the porous capillary diversion layer is formed by the following steps of: sintering a plurality of metallic pellets on the inner wall of the tube and the inner wall of the chamber; and disposing a metallic net body on the plurality of metallic pellets to form the porous capillary diversion layer.
In another embodiment, the porous capillary diversion layer is formed by the following steps of: laying a wavy carped metal cloth on the inner wall of the tube and the inner wall of the chamber; and disposing a flat metal net fabric layer on the wavy carped metal cloth to form the porous capillary diversion layer.
Another heat pipe making method of the invention comprises the steps of: (A) providing a first tube having an open and a closed end; (B) shrinking the neck of the first tube to form a chamber and a second tube, and the chamber and the second tube are mutually through, wherein the chamber comprises the closed end, the second comprises the open; (C) vacuuming the chamber and the second tube; and (D) sealing the open. Wherein, the inner wall of the chamber and the inner wall of the second tube comprise a porous capillary diversion layer; the chamber and the second tube contain a working fluid; a cross-section area of the chamber is larger than the cross-section area of the second tube. Wherein step (B) is operated in a temperature range from 400° C. to 600° C.
In an embodiment, after step (A) is performed, the porous capillary diversion layer is formed on the inner wall of the first tube. The porous capillary diversion layer is formed by the following steps of: disposing a first metallic powder into the first tube; interposing a center pillar into the first tube from the open and the center pillar is approximately tightly against on the first metallic powder; filling a second metallic powder between the center pillar and the inner wall of the first tube; performing a sintering process to make the first metallic powder and the second metallic powder mutually welded to form the porous capillary diversion layer; and getting the center pillar out of the first tube.
Accordingly, the invention is to provide a heat pipe having different cross-section areas and making method thereof to provide an effective and rapid heat-dissipating mechanism for the electric component, with larger heat area or a group of electric components, disposed on the flat end of the heat pipe.
The objective of the present invention will no doubt become obvious to those of ordinary skill in the art after reading the following detailed description of the preferred embodiment, which is illustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE APPENDED DRAWINGS

FIG. 1 illustrates a cross-sectional view of the not-finished heat pipe of a first preferred embodiment.

FIG. 2A illustrates a cross-sectional view of a semi-finished heat pipe of the first preferred embodiment.

FIG. 2B illustrates a cross-sectional view that a center pillar is interposed into the semi-finished heat pipe of the first preferred embodiment.

FIG. 2C illustrates a cross-sectional view that a first metallic powder is filled between the center pillar and the semi-finished heat pipe of the first preferred embodiment.

FIG. 2D illustrates a cross-sectional view of a semi-finished heat pipe of the first preferred embodiment.

FIG. 2E illustrates a cross-sectional view of the heat pipe of the first preferred embodiment.

FIG. 3A illustrates a partial cross-sectional view of a first open of the heat pipe and a second open of the heat pipe of an embodiment.

FIG. 3B illustrates a partial cross-sectional view that a first open of the heat pipe and a second open of the heat pipe are engaged of the embodiment.

FIG. 3C illustrates a partial cross-sectional view that a first open of the heat pipe and a second open of the heat pipe of an embodiment.

FIG. 3D illustrates a partial cross-sectional view that a first open of the heat pipe and a second open of the heat pipe are engaged of the embodiment.

FIG. 3E illustrates a cross-sectional view of the chamber of the heat pipe of the above-mentioned embodiment.

FIG. 4A illustrates a cross-sectional view of a semi-finished heat pipe of a second preferred embodiment.

FIG. 4B illustrates a cross-sectional view that a center pillar is interposed into the semi-finished heat pipe of the second preferred embodiment.

FIG. 4C illustrates a cross-sectional view that a second metallic powder is filled between the center pillar and the semi-finished heat pipe of the second preferred embodiment.

FIG. 4D illustrates a cross-sectional view of the heat pipe of the second preferred embodiment.

FIG. 4E illustrates a cross-sectional view that the heat pipe has not finished of an embodiment.

FIG. 4F illustrates a cross-sectional view that the heat pipe has not finished of the embodiment.

FIG. 4G illustrates a cross-sectional view of the heat pipe of the embodiment.

FIG. 4H illustrates a cross-sectional view of the chamber of the heat pipe of the above-mentioned embodiment.

FIG. 5 illustrates a cross-sectional view of the heat pipe of a third preferred embodiment.

FIG. 6 illustrates a cross-sectional view of the heat pipe of a fourth preferred embodiment.

FIG. 7 illustrates a cross-sectional view of the heat pipe of a fifth preferred embodiment.

FIG. 8A illustrates a cross-sectional view of a first tube of the heat pipe of a sixth preferred embodiment.

FIG. 8B illustrates a cross-sectional view that after the first tube is shrank the neck of the sixth preferred embodiment.

FIG. 8C illustrates a cross-sectional view of the heat pipe of the sixth preferred embodiment.

FIG. 8D illustrates a cross-sectional view that a first metallic powder is filled into the first tube of the sixth preferred embodiment.

FIG. 8E illustrates a cross-sectional view that the center pillar is interposed into the first tube of the sixth preferred embodiment.

FIG. 8F illustrates a cross-sectional view that a second metallic powder between the center pillar and the first tube of the sixth preferred embodiment.

FIG. 8G illustrates a cross-sectional view of the first tube of the sixth preferred embodiment.

DETAILED DESCRIPTION OF THE INVENTION

Please refer to FIG. 1. FIG. 1 illustrates a cross-sectional view of the not-finished heat pipe 1 according to a first preferred embodiment of the invention. The heat pipe 1 includes a tube 12 and a chamber 14. The tube 12 has a first open 122 and a third open 124. The chamber 14 has a second open 142 and a flat end 144. The cross-section area of the chamber 14 is larger than the cross-section area of the tube 12. Wherein, the cross-section area of the chamber 14 means the cross-section area near the flat end 144. The diameter of the tube 12 is smaller than 10 mm.
The second open 142 of the chamber 14 and the first open 122 of the tube 12 are tightly joined together to form a semi-finished heat pipe 16, as shown in FIG. 2A. The tight joining can be performed through a process of welding, soldering, machine fastening, or gluing.
According to the first preferred embodiment, a sintered metallic powder layer 182 has been formed on the inner wall of the chamber 14, as shown in FIG. 2A. After the tight joining is performed, a center pillar C1 is interposed into the semi-finished heat pipe 16 from the third open 124, and the center pillar C1 is approximately tightly against the sintered metallic powder layer, as shown in FIG. 2B. Then, a first metallic powder 184 is filled between the center pillar C1 and the semi-finished heat pipe 16, as shown in FIG. 2C. The first metallic powder 184 can be a copper powder, a nickel powder, a silver powder, a metallic powder plated with copper, nickel, silver, or other similar metallic powders.
Next, a sintering process is performed to make the first metallic powder 184 and the sintered metallic powder 182 mutually welded to form a porous capillary diversion layer 18. At last, the center pillar C1 is gotten out of the semi-finished heat pipe 16, as shown in FIG. 2D. Before the third open 124 is sealed, it needs to vacuum the semi-finished heat pipe 16 and pour a working fluid L1 into the semi-finished heat pipe 16. The sequences of pouring the working fluid L1 and vacuuming the gas can be exchanged. The third open 124 can be shrunk before vacuuming, so that the following sealing can be smoothly performed. Finally, after the third open 14 is sealed, the heat pipe 1 is finished, as shown in FIG. 2E.
By the way, the tight joining should avoid over-damaging the porous capillary diversion layer. In the first preferred embodiment, the second open 124 of the chamber has no sintered metallic powder layer 182 (please refer to FIG. 2A). Therefore, during the tight joining process, the damage to the sintered metallic powder layer 182 is unnecessary to be considered, and a general welding process or a general soldering process can be used. However, it should be still noted, after the tight joining, the inner wall of the chamber 14 and the inner wall of the tube 12 should keep joining smoothly, so that the following first metallic powder 184 can be smoothly sintered, and the first metallic powder 184 and the sintered metallic powder 182 can be mutually welded to form the porous capillary diversion layer 18.
In addition, if the second open 142 of the chamber 14 has the sintered metallic powder 182, the used joining process or the using condition will be limited. For example, it is not suitable to directly use a welding process or a soldering process in this case. However, if the joining is well-designed, the welding process or the soldering process can be used. Please refer to FIG. 3A. FIG. 3A illustrates a partial cross-sectional schematic diagram of the first open 122 and the second open 142 according to an embodiment. The first open 122 includes a joining plane 1222 and a welding portion 1224. The second open 142 includes a joining plane 1422 and a welding portion 1424. The joining planes 1222 and 1442 are tightly cohered to each other. The joining planes 1222 and 1442 are both inclined planes. After the joining planes 1222 and 1442 are cohered, the welding portions 1224 and 1424 will form a concave to provide the filling material welding. After the tight joining is finished, only the welding portions 1224 and 1424 are affected to be filled with a welding material P thereon, the joining planes 1222 and 1442 are not affected, so that the inner wall of the chamber 14 and the inner wall of the tube 12 can be still smoothly connected, and the sintered metallic powder 182 of the second open 142 of the chamber 14 can not be damaged, as shown in FIG. 3B.
Furthermore, please refer to FIG. 3C. FIG. 3C illustrates a partial cross-sectional view of the first open 122 and the second open 142 according to another embodiment. The first open 122 includes a joining plane 1222 and a welding portion 1224. The second open 142 includes a joining plane 1422 and a welding portion 1424. The joining planes 1222 and 1442 both comprise a protrusion 1224 a, 1424 a and a concave 1224 b, 1424 b. After the joining planes 1222 and 1442 are cohered, the joining planes 1222 and 1442 are tightly cohered to each other, the protrusions 1224 a, 1424 a are mutually weld through a heating process or a soldering process, and the concaves 1224 b and 1424 b are fully filled. After the tight joining is finished, only the welding portions 1224 and 1424 are affected, the joining planes 1222 and 1442 are not affected, so that the inner wall of the chamber 14 and the inner wall of the tube 12 can be still smoothly connected, and the sintered metallic powder 182 of the second open 142 of the chamber 14 will not be damaged, as shown in FIG. 3D. The dotted line circles in FIG. 3D show the soldering regions of the welding portions 1224 and 1424. Of course, if the first open 122 and the second open 142 are joined by a screw thread locking method, the above-mentioned effects due to heat will not exist. But the sealing effect of the tight joining should be noticed.
It should be mentioned that in the above-mentioned embodiment, the chamber 14 can include a concave 146 and an upper cover 148. The concave 146 includes the flat end 144 and the upper cover 148 includes the second open 142. A first sintered metal layer 1822 is formed on the concave 146. A second sintered metal layer 1824 is formed on the upper cover 148. The upper cover 148 and the concave 146 are engaged to form the chamber 14, and the sintered metallic powder layer 182 is formed by the first sintered metal layer 1822 and the second sintered metal layer 1824. Additionally, the casing body of the concave 146 itself can be made through a process of powder metallurgy, stamping, injection molding, casting, or machining.
Please refer to FIG. 4A. FIG. 4A illustrates a cross-sectional view of the not-finished heat pipe 2 according to a second preferred embodiment. The making method of the heat pipe 2 is approximately same with the heat pipe 1 of the first preferred embodiment, so it will no longer be explained again here. Then, the forming method of the porous capillary diversion layer 28 of the heat pipe 2 will be introduced in detail.
As shown in FIG. 4A, the inner wall of the chamber 24 of the heat pipe 2 has a plurality of tiny notches 282. A center pillar C2 is interposed into a semi-finished heat pipe 26 from the third open 224 of the tube 22 of the heat pipe 2, and the center pillar C2 is approximately tightly against the plurality of tiny notches 282, as shown in FIG. 4B. Then, a second metallic powder is filled between the center pillar C2 and the semi-finished heat pipe 26, as shown in FIG. 4C. Next, a sintering process is performed to make the second metallic powder 284 and the plurality of tiny notches 282 mutually welded to form the porous capillary diversion layer 28. Finally, the center pillar C2 is gotten out of the semi-finished heat pipe 26. And, the heat pipe 2 is formed after sealing the third open 224, as shown in FIG. 4D.
By the way, the outer diameter of the center pillar C2 is not limited by one, namely the center pillar C2 may have different outer diameters. Please refer to FIG. 4E. FIG. 4E illustrates a cross-sectional view of the not-finished heat pipe 2′ according to an embodiment. Compared to the second preferred embodiment, the plurality of tiny notches 282′ of the chamber 24′ of the heat pipe 2′ shows the same inner diameter with the tube 22′ of the heat pipe 2′, therefore, the center pillar having only one outer diameter will not be tight against the plurality of tiny notches 282′ and has a space existed between the center pillar and the semi-finished heat pipe 26′ of the heat pipe 2′ to contain the following added metallic powder. Under this condition, a center pillar C2′ must have different outer diameters, so that one part of the center pillar C2′ can be tightly against the plurality of tiny notches 282′ and there will be a space existed between the center pillar C2′ and the heat pipe 2′ to contain the following added second metallic powder 284′. In the following sintering process, the second metallic powder 284′ and the plurality of tiny notches 282′ are mutually welded to form a porous capillary diversion layer 28′, as shown in FIG. 4F. After sealing the semi-finished heat pipe 26′, heat pipe 2′ will be formed, as shown in FIG. 4G.
It should be mentioned that in the above-mentioned embodiment, the chamber 24 and 24′ can include a concave 246 and an upper cover 248. The upper cover 248 includes the second open 242 of the chamber 24. A plurality of first tiny notches 2822 is formed on the concave 246. A plurality of second tiny notches 2824 is formed on the upper cover 248. The concave 246 and the upper cover 248 are engaged together to form the chamber 24, 24′, and the plurality of first tiny notches 2822 and the plurality of second tiny notches 2824 form the plurality of tiny notches 282, as shown in FIG. 4H. Additionally, the casing body of the concave 246 itself can be made through a process of powder metallurgy, stamping, injection molding, casting, or machining.
Please refer to FIG. 5. FIG. 5 illustrates a cross-sectional view of the heat pipe 3 according to a third preferred embodiment. The making method of the heat pipe 3 is approximately same with the heat pipe 1 of the first preferred embodiment, so it will no longer be explained again here. Then, the forming method of the porous capillary diversion layer 38 of the heat pipe 3 will be introduced in detail. The porous capillary diversion layer 38 is formed through a machining process to make the plurality of tiny notches 38 on the inner wall of the tube 32 of the heat pipe 3 and the inner wall of the chamber 34 of the heat pipe 3. For example, the plurality of tiny notches 38 can be formed on the inner wall of the semi-finished heat pipe by directly cutting via a knife. By the way, in an embodiment, since the chamber of the semi-finished heat pipe already has the plurality of tiny notches, after the tight joining is performed, the only thing needed to do is to generate the plurality of tiny notches on the other portions of the semi-finished heat pipe to form a porous capillary diversion layer. However, the connection between these two sets of tiny notches should be noticed. This chamber is always found in the combined chamber, such as a chamber assembled by a concave and an upper cover.
Please refer to FIG. 6. FIG. 6 illustrates a cross-sectional view of the heat pipe 4 according to a fourth preferred embodiment. The making method of the heat pipe 4 is approximately the same with the heat pipe 1 of the first preferred embodiment, so it will no longer be explained again here. Then, the forming method of the porous capillary diversion layer 48 of the heat pipe 4 will be introduced in detail. Firstly, a plurality of metallic pellets 482 is sintered on the inner wall of the tube 42 of the heat pipe 4 and the inner wall of the chamber 44 of the heat pipe 4. Then, a metallic net body 484 is disposed on the plurality of metallic pellets 482 to form the porous capillary diversion layer 48. By the way, the plurality of metallic pellets 482 can be sintered on the inner wall of the tube 42 and the inner wall of the chamber 44 respectively.
Please refer to FIG. 7. FIG.7 illustrates a cross-sectional view of the heat pipe 5 according to a fifth preferred embodiment. The making method of the heat pipe 5 is approximately the same with the heat pipe 1 of the first preferred embodiment, so it will no longer be explained again here. Then, the forming method of a porous capillary diversion layer 58 of the heat pipe 5 will be introduced in detail. Firstly, a wavy carped metal cloth 582 is laid on the inner wall of the tube 52 of the heat pipe 5 and the inner wall of the chamber 54 of the heat pipe 5. Then, a flat metal net fabric layer 584 is disposed on the wavy carped metal cloth 582 to form the porous capillary diversion layer 58. Wherein, the wavy carped of the wavy carped metal cloth 582 can be in a form of triangle, rectangle, trapezium, or wave.
Please refer to FIG. 8. FIG. 8 illustrates a cross-sectional view of the first tube 62 of the heat pipe 6 according to a sixth preferred embodiment. The first tube 62 has an open 622 and a closed end 624. The closed end 624 is flat. The first tube 62 has larger inner diameter, so that the following neck-shrinking process can be smoothly performed. And, because it is the tube wall of the first tube 62 shrunk by the shrinking neck process, and the tube wall will become thicker after the neck-shirking process, the wall thickness of the closed end 624 of the first tube 62, in general applications, will be thicker than that before the neck-shirking process, so that a uniform wall thickness can be obtained after the neck-shirking process. But it is not limited to this.
Next, a chamber 626 and a second tube 628 are formed by shrinking the neck of the first tube 62, and the chamber 626 and the second tube 628 are mutually through, as shown in FIG. 8B. The chamber 626 includes the closed end 624, and the second tube 628 includes the open 622. A cross-section area of the chamber 626 is larger than a cross-section area of the second tube 628. The cross-section area of the chamber 626 means the cross-section area of the closed end. In addition, the chamber 626 and the inner wall of the second tube 628 include a porous capillary diversion layer 64.
Then, the chamber 626 and the second tube 628 are vacuumed, and a working fluid L2 is poured into the chamber 626 and the second tube 628 respectively. Finally, the open 622 is sealed. Wherein, the sequence of the pouring the working fluid L2 step and the vacuuming the gas step can be exchanged. After the open 622 is sealed, the heat pipe 6 is finished, as shown in FIG. 8C.
According to the sixth preferred embodiment, the shrunk neck is heated in a temperature range from 400° C. to 600° C., or the shrunk neck is heated in a temperature range from the recrystallization temperature of the first tube 62 to the temperature that about 200° C. over the recrystallization temperature. Additionally, the porous capillary diversion layer 64 is formed on the inner wall of the first tube 62 before the neck-shrinking by the following steps of: disposing a first metallic powder 642 into the first tube 62, as shown in FIG. 8D; interposing a center pillar C3 into the first tube 62 from the open 622 and the center pillar C3 is approximately tightly against on the first metallic powder 642, as shown in FIG. 8E; filling a second metallic powder 644 between the center pillar C3 and the inner wall of the first tube 62; performing a sintering process to make the first metallic powder 642 and the second metallic powder 644 mutually welded to form the porous capillary diversion layer 64; and getting the center pillar C3 out of the first tube 62, as shown in FIG. 8G.
In the above-mentioned embodiment, the tube and the chamber are joined in a symmetrical method. In practical applications, the tube and the chamber can be also joined in an unsymmetrical method. For example, the tube can be connected to the edge of the chamber to meet different space limitations.
To sum up, the invention provides a heat pipe having different cross-section areas and making method thereof to provide an effective and rapid heat-dissipating mechanism for the electric component, with larger heat area or a group of electric components, disposed on the flat end of the heat pipe.
Although the present invention has been illustrated and described with reference to the preferred embodiment thereof, it should be understood that it is in no way limited to the details of such embodiment but is capable of numerous modifications within the scope of the appended claims.

Claims

1. A heat pipe, applied to a light emitting diode (LED), the heat pipe comprising:

a tube having a first open, the diameter of the tube being smaller than a distance of 10 mm;

a chamber having a second open, the second open and the first open being tightly joined together to form a sealed space via the tube and the chamber; and

a porous capillary diversion layer, formed in the tube and the chamber;

wherein the sealed space contains a working fluid, and a cross-section area of the chamber is larger than a cross-section area of the tube.

2. The heat pipe of claim 1, wherein the tube and the chamber are formed in one piece.

3. The heat pipe of claim 1, wherein the chamber comprises a concave and an upper cover, and the upper cover is engaged with the concave and the upper cover has the second open.

4. The heat pipe of claim 3, wherein the concave is made through a process of powder metallurgy, stamping, injection molding, casting, or machining.

5. The heat pipe of claim 1, wherein the chamber has a flat end.

6. The heat pipe of claim 1, wherein the porous capillary diversion layer is made by sintering a copper powder, a nickel powder, a silver powder, a metallic powder plated with copper, nickel, silver, or other similar metallic powders.

7. The heat pipe of claim 1, wherein the porous capillary diversion layer comprises a metallic pellet layer and a metallic net body, the metallic pellet layer is formed on the inner wall of the tube and the inner wall of the chamber by sintering, and the metallic net body is disposed upon the metallic pellet layer.

8. The heat pipe of claim 1, wherein the porous capillary diversion layer comprises a wavy carped metal cloth and a flat metal net fabric layer, the wavy carped metal cloth is spread on the inner wall of the tube and the inner wall of the chamber, and the flat metal net fabric layer is disposed on the wavy carped metal cloth.

9. The heat pipe of claim 8, wherein the wavy carped of the wavy carped metal cloth is in a form of triangle, rectangle, trapezium or wave.

10. The heat pipe of claim 1, wherein the porous capillary diversion layer comprises a plurality of tiny notches formed on the inner wall of the tube and the inner wall of the chamber.

11. The heat pipe of claim 1, wherein the porous capillary diversion layer comprises a plurality of tiny notches and a metallic sintered layer, the tiny notches are formed on the inner wall of the chamber, and the metallic sintered layer is formed on the inner wall of the tube and the metallic sintered layer is welded with the tiny notches.

12. A method of making a heat pipe, comprising the steps of:

(a) providing a tube having a first open and a third open;

(b) providing a chamber having a second open;

(c) tightly joining the first open of the tube and the second open of the chamber together to form a semi-finished heat pipe;

(d) vacuuming the semi-finished heat pipe; and

(e) sealing the third open;

wherein the inner wall of the semi-finished heat pipe comprises a porous capillary diversion layer, the semi-finished heat pipe contains a working fluid, and the cross-section area of the chamber is larger than the cross-section area of the tube.

13. The method of the claim 12, wherein the chamber has a flat end.

14. The method of claim 12, wherein in step (c), the tight joining is performed through a process of welding, soldering, machine fastening, or gluing.

15. The method of claim 12, wherein the working fluid is poured into the semi-finished heat pipe before or after step (d) is performed.

16. The method of claim 12, wherein a sintered metallic powder layer is formed on the inner wall of the chamber, and the porous capillary diversion layer is formed by the following steps of:

interposing a center pillar into the semi-finished heat pipe from the third open and the center pillar being approximately tightly against the sintered metallic powder layer;

filling a first metallic powder between the center pillar and the semi-finished heat pipe;

performing a sintering process to make the first metallic powder and the metallic powder mutually welded to form the porous capillary diversion layer; and

getting the center pillar out of the semi-finished heat pipe.

17. The method of claim 12, wherein the inner wall of the chamber has a plurality of tiny notches, and the porous capillary diversion layer is formed by the following steps of:

interposing a center pillar into the semi-finished heat pipe from the third open and the center pillar being approximately tightly against the plurality of tiny notches;

filling a second metallic powder between the center pillar and the semi-finished heat pipe;

performing a sintering process to make the second metallic powder and the plurality of tiny notches mutually welded to form the porous capillary diversion layer; and

getting the center pillar out of the semi-finished heat pipe.

18. The method of claim 16 or 17, wherein the first metallic powder or the second metallic powder is a copper powder, a nickel powder, a silver powder, a metallic powder plated with copper, nickel, silver metal powder, or other metallic powders.

19. The method of claim 12, wherein the porous capillary diversion layer is formed by the following step of:

using a machining process to make the plurality of tiny notches on the inner wall of the tube and the inner wall of the chamber to form the porous capillary diversion layer.

20. The method of claim 12, wherein the porous capillary diversion layer is formed by the following steps of:

sintering a plurality of metallic pellets on the inner wall of the tube and the inner wall of the chamber; and

disposing a metallic net body on the plurality of metallic pellets to form the porous capillary diversion layer.

21. The method of claim 12, wherein the porous capillary diversion layer is formed by the following steps of:

laying a wavy carped metal cloth on the inner wall of the tube and the inner wall of the chamber; and

disposing a flat metal net fabric layer on the wavy carped metal cloth to form the porous capillary diversion layer.

22. The method of claim 12, wherein step (b) comprises the steps of:

providing a concave;

providing a upper cover, the upper cover has the second open; and

engaging the upper cover and the concave to form the chamber.

23. The method of claim 22, wherein a first sintered metal layer is formed on the concave, a second sintered metal layer is formed on the upper cover, and the first sintered metal layer is engaged with the second sintered metal layer.

24. The method of claim 22, wherein a plurality of first tiny notches is formed on the concave, a plurality of second tiny notches is formed on the upper cover, and the plurality of first tiny notches is engaged with the plurality second of tiny notches.

25. The method of claim 22, wherein the concave is made through a process of powder metallurgy, stamping, injection molding, casting, or machining.

26. A method of making a heat pipe, comprising the steps of:

(A) providing a first tube having an open and a closed end;

(B) shrinking the neck of the first tube to form a chamber and a second tube, the chamber and the second tube being mutually through, wherein the chamber comprises the closed end, and the second comprises the open;

(C) vacuuming the chamber and the second tube; and

(D) sealing the open;

wherein the inner wall of the chamber and the inner wall of the second tube comprise a porous capillary diversion layer, the chamber and the second tube contain a working fluid, a cross-section area of the chamber is larger than the cross-section area of the second tube.

27. The method of claim 26, wherein the closed end is flat.

28. The method of claim 26, wherein step (B) is operated in a temperature range from 400° C. to 600° C.

29. The method of claim 26, further comprising:

after step (A) is performed, forming the porous capillary diversion layer on the inner wall of the first tube.

30. The method of claim 29, wherein the porous capillary diversion layer is formed by the following steps of:

disposing a first metallic powder into the first tube;

interposing a center pillar into the first tube from the open and the center pillar being approximately tightly against on the first metallic powder;

filling a second metallic powder between the center pillar and the inner wall of the first tube;

performing a sintering process to make the first metallic powder and the second metallic powder mutually welded to form the porous capillary diversion layer; and

getting the center pillar out of the first tube.