US20140246176A1

US20140246176A1 - Heat dissipation structure

Info

Publication number: US20140246176A1
Application number: US13/784,743
Authority: US
Inventors: Hsiu-Wei Yang
Original assignee: Asia Vital Components Co Ltd
Current assignee: Asia Vital Components Co Ltd
Priority date: 2013-03-04
Filing date: 2013-03-04
Publication date: 2014-09-04

Abstract

A heat dissipation structure includes a main body. The main body has a chamber. The chamber has an evaporation section, a condensation section, a first backflow section and a second backflow section. The evaporation section and the condensation section and the first and second backflow sections communicate with each other. A junction between the first and second backflow sections is coated with a heat insulation coating. A working fluid is filled in the chamber. By means of the heat insulation coating, the heat leakage between the evaporation section and the condensation section can be avoided. In this case, the vapor-liquid circulation of the working fluid in the heat dissipation structure can be continuously successfully performed.

Description

BACKGROUND OF THE INVENTION

1. Field of the Invention
The present invention relates generally to a heat dissipation structure, and more particularly to a heat dissipation structure capable of avoiding heat leakage in the heat dissipation structure so as to ensure stable vapor-liquid circulation of the working fluid in the heat dissipation structure.
2. Description of the Related Art
There is a trend to develop thinner and thinner electronic apparatuses nowadays. The ultra-thin electronic apparatus includes miniaturized components. The heat generated by the miniaturized components of the electronic apparatus has become a major obstacle to having better performance of the electronic apparatus and system. Even if the semiconductors forming the electronic component have been more and more miniaturized, the electronic apparatus is still required to have high performance.
The miniaturization of the semiconductors will lead to increase of thermal flux. The challenge to cooling the product due to increase of thermal flux exceeds the challenge simply caused by increase of total heat. This is because the increase of thermal flux will lead to overheating at different times with respect to different sizes and may cause malfunction or even burnout of the electronic apparatus.
In order to solve the problem of narrow heat dissipation space of the conventional technique, a vapor chamber (VC) is generally positioned on the chip as a heat sink. In order to increase the capillarity limit, capillary structures such as copper posts, sintered coatings, sintered posts and foamed posts are disposed in the vapor chamber as support structures and backflow passages. However, such structures are only applicable to the micro-vapor chamber with thinner upper and lower walls (under 1.5 mm).
The vapor chamber serves to face-to-face vertically transfer heat. Generally, the heat is transferred from one plane face to the other plane face. The vapor chamber advantageously has larger heat transfer area and is able to quickly transfer the heat. However, the vapor chamber has a critical shortcoming that it can hardly transfer the heat to a remote end for dissipating the heat. In the case that the heat is not dissipated in time, the heat will accumulate around the heat source.
Moreover, in order to achieve the object of thinning the vapor chamber more, the loop heat pipe technique is applied to the vapor chamber. The opposite sides of two thin copper sheets are respectively formed with micro-flow passages to form the evaporation section and the condensation section and the backflow sections. A working fluid is filled in the chamber to perform vapor-liquid circulation. The most often seen problem of the loop heat pipe is heat leakage. This problem is more likely to happen in the narrower flow passages. This will hinder the condensed working fluid from flowing back to the evaporation section and cause cease of the vapor-liquid circulation of the working fluid in the vapor chamber. Eventually, the vapor chamber will lose its heat transfer function.

SUMMARY OF THE INVENTION

It is therefore a primary object of the present invention to provide an ultra-thin heat dissipation structure, which is capable of avoiding heat leakage so as to enhance heat dissipation performance.
To achieve the above and other objects, the heat dissipation structure of the present invention includes a main body. The main body has a chamber. The chamber has an evaporation section, a condensation section, a first backflow section and a second backflow section. The evaporation section and the condensation section and the first and second backflow sections communicate with each other. A junction between the first and second backflow sections is coated with a heat insulation coating. A working fluid is filled in the chamber. By means of the heat insulation coating, the heat leakage between the evaporation section and the condensation section can be avoided. In this case, the vapor-liquid circulation of the working fluid in the heat dissipation structure can be continuously successfully performed.
The heat dissipation structure of the present invention is applied to a narrow site with limited space. The heat dissipation structure is ultra-thin and is capable of avoiding heat leakage in the heat dissipation structure so as to enhance heat transfer effect of the heat dissipation structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The structure and the technical means adopted by the present invention to achieve the above and other objects can be best understood by referring to the following detailed description of the preferred embodiments and the accompanying drawings, wherein:

FIG. 1 is a perspective view of a first embodiment of the heat dissipation structure of the present invention;

FIG. 2 is a sectional view taken along line A-A of FIG. 1;

FIG. 3 is a sectional view taken along line A-A of FIG. 1;

FIG. 4 is a sectional view taken along line B-B of FIG. 1;

FIG. 5 is a perspective exploded view of a second embodiment of the heat dissipation structure of the present invention; and

FIG. 6 is a perspective assembled view of the second embodiment of the heat dissipation structure of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Please refer to FIGS. 1, 2, 3 and 4. FIG. 1 is a perspective view of a first embodiment of the heat dissipation structure of the present invention. FIG. 2 is a sectional view taken along line A-A of FIG. 1. FIG. 3 is a sectional view taken along line A-A of FIG. 1. FIG. 4 is a sectional view taken along line B-B of FIG. 1. According to the first embodiment, the heat dissipation structure of the present invention includes a main body 1.
The main body 1 has a chamber 11 having an evaporation section 111, a condensation section 112, a first backflow section 113 and a second backflow section 114. The evaporation section 111 and the condensation section 112 and the first and second backflow sections 113, 114 communicate with each other. A junction between the first and second backflow sections 113, 114 is coated with a heat insulation coating 2. A working fluid 3 is filled in the chamber 11.
To speak more specifically, the chamber 11 of the main body has a first side 11 a and a second side 11 b. The evaporation section 111 and the first backflow section 113 on the first side 11 a have multiple channels. The condensation section 112 and the second backflow section 114 have multiple flow ways. The evaporation section 111 and the condensation section 112 on the second side 11 b have multiple flow ways. The first and second sides 11 a, 11 b correspond to each other. The evaporation section 111 and the condensation section 112 and the first and second backflow sections 113, 114 together define the chamber 11.
The first backflow section 113 is disposed on two adjacent sides of the evaporation section 111. The second backflow section 114 is disposed on two adjacent sides of the condensation section 112.
After the working fluid 3 in the evaporation section 111 is heated and converted from liquid phase into vapor phase, the working fluid 3 spreads to the condensation section 112. Then the working fluid 3 is cooled and converted from vapor phase into liquid phase in the condensation section 112. Thereafter, the working fluid 3 flows back to the evaporation section 111 through the second backflow section 114 on two sides of the condensation section 112 and through the first backflow section 113 on two sides of the evaporation section 111 in communication with the first backflow section 113.
The present invention is characterized in that the junction between the first and second backflow sections 113, 114 or a section adjacent to the junction is coated with the heat insulation coating 2 to avoid heat leakage.
Please now refer to FIGS. 5 and 6. FIG. 5 is a perspective exploded view of a second embodiment of the heat dissipation structure of the present invention. FIG. 6 is a perspective assembled view of the second embodiment of the heat dissipation structure of the present invention. The second embodiment is partially identical to the first embodiment in structure and thus will not be repeatedly described hereinafter. The second embodiment is different from the first embodiment in that the main body 1 has an upper cover 11 c and a lower cover 11 d. The evaporation section 111 and the first backflow section 113 on the lower cover 11 d have multiple channels. The condensation section 112 and the second backflow section 114 have multiple flow ways. The evaporation section 111 and the condensation section 112 on the upper cover 11 c have multiple flow ways. The upper and lower covers 11 c, 11 d are correspondingly mated with each other. The evaporation section 111 and the condensation section 112 and the first and second backflow sections 113, 114 together define the chamber 11. The upper and lower covers 11 c, 11 d are connected with each other by means of diffusion bonding.
The heat insulation coating 2 of the first and second embodiments is made of a material selected from a group consisting of ceramic material and stainless steel material.
In the present invention, the vapor-liquid circulation technique of the loop heat pipe is applied to the ultra-thin vapor chamber heat dissipation structure. The main shortcoming of the conventional loop heat pipe is heat leakage. This will make it impossible for the condensed working fluid to flow back to the evaporation section. To overcome this shortcoming, the junction between the backflow section of the condensation section and the backflow section of the evaporation section is coated with a heat insulation coating to avoid heat leakage. In this case, the vapor-liquid circulation of the working fluid in the vapor chamber can be successfully continuously performed.
The first and second embodiments of the present invention can avoid heat leakage inside the heat dissipation structure so that it is ensured that the vapor-liquid circulation of the working fluid in the heat dissipation structure can be stably performed.
The present invention has been described with the above embodiments thereof and it is understood that many changes and modifications in the above embodiments can be carried out without departing from the scope and the spirit of the invention that is intended to be limited only by the appended claims.

Claims

What is claimed is:

1. A heat dissipation structure comprising a main body, the main body having a chamber, the chamber having an evaporation section, a condensation section, a first backflow section and a second backflow section, the evaporation section and the condensation section and the first and second backflow sections communicating with each other, a junction between the first and second backflow sections being coated with a heat insulation coating, a working fluid being filled in the chamber.

2. The heat dissipation structure as claimed in claim 1, wherein the first backflow section is disposed on two adjacent sides of the evaporation section, while the second backflow section is disposed on two adjacent sides of the condensation section.

3. The heat dissipation structure as claimed in claim 1, wherein the heat insulation coating is made of a material selected from a group consisting of ceramic material and stainless steel material.

4. The heat dissipation structure as claimed in claim 1, wherein the main body has an upper cover and a lower cover, the evaporation section and the first backflow section on the lower cover having multiple channels, the condensation section and the second backflow section having multiple flow ways, the evaporation section and the condensation section on the upper cover having multiple flow ways, the upper and lower covers being correspondingly mated with each other, the evaporation section and the condensation section and the first and second backflow sections together defining the chamber.

5. The heat dissipation structure as claimed in claim 4, wherein the upper and lower covers are connected with each other by means of diffusion bonding.

6. The heat dissipation structure as claimed in claim 1, wherein the chamber has a first side and a second side, the evaporation section and the first backflow section on the first side having multiple channels, the condensation section and the second backflow section having multiple flow ways, the evaporation section and the condensation section on the second side having multiple flow ways, the first and second sides corresponding to each other, the evaporation section and the condensation section and the first and second backflow sections together defining the chamber.