Heat plate and electronic device

Abstract

The present disclosure discloses a kind of vapor chamber and electronic equipment, belong to heat dissipation technical field.The vapor chamber includes shell, first capillary structure and working substance;First capillary structure and working substance are located in shell, and the area of the projection of first capillary structure on the first inner surface of shell is less than the area of first inner surface, there is cavity in shell, and the working substance in liquid state is located in first capillary structure, and the working substance in gaseous state is located in cavity;The area in shell includes first area and second area, first capillary structure includes the first part located in first area and the second part located in second area, second part includes stem structure and branch structure, branch structure includes at least one branch, and each branch is in contact with stem structure or close to stem structure.By using the present disclosure, liquid working substance in second area can be absorbed in first capillary structure as much as possible, to avoid the ice formation of liquid working substance not absorbed at low temperature, and to avoid the bulging of shell.

Description

Technical Field

[0001] This disclosure relates to the field of heat dissipation technology, and in particular to a heat spreader and electronic device. Background Technology

[0002] Heat sinks are widely used in electronic devices, especially high-performance and high-capacity electronic devices, such as laptops, tablets and servers.

[0003] As electronic devices become increasingly thinner, heat spreaders also need to become thinner. However, as the thickness of the heat spreader decreases, its shell wall is prone to bulging, which affects the heat source in contact with the heat spreader. Summary of the Invention

[0004] This disclosure provides a heat spreader and an electronic device, which can solve the problem in related technologies where the heat spreader's shell wall is prone to bulging as the thickness decreases. The technical solution is as follows:

[0005] In a first aspect, a heat spreader is provided, the heat spreader comprising a shell, a first capillary structure, and a working fluid; both the first capillary structure and the working fluid are located in the shell, and the area of ​​the projection of the first capillary structure onto a first inner surface of the shell is smaller than the area of ​​the first inner surface, so that a cavity can be formed inside the shell; the working fluid is converted between a gaseous state and a liquid state, and the liquid working fluid is located in the first capillary structure, while the gaseous working fluid is located in the cavity;

[0006] The area within the shell includes a first area and a second area, wherein the first area corresponds to the area where the heat source is located, and the second area is different from the first area. The first capillary structure includes a first part located in the first area and a second part located in the second area. The second part includes a main structure and a branch structure. The main structure is connected to the first part, and the branch structure corresponds to the area where the cold source is located and includes at least one branch. Each branch is in contact with or close to the main structure.

[0007] The first region corresponds to the heat source. For example, when the heat spreader dissipates heat from the heat source, the outer surface of the heat spreader's shell wall in the first region contacts the outer surface of the heat source so that the heat generated when the heat source is working is transferred to the shell wall located in the first region.

[0008] The second region is different from the first region. For example, the second region can be a region corresponding to a cold source, such as a region adjacent to a cold source, which can be a fan.

[0009] In this context, branches and trunk structures are in contact, for example, branches and trunk structures are connected; branches and trunk structures are close to each other, for example, branches and trunk structures are not connected; the two can be parallel or non-parallel and form an angle.

[0010] The scheme disclosed herein includes a first capillary structure in the second part of the second region, comprising a main structure and branch structures, with the branch structures further comprising at least one branch. This allows the liquid working fluid in the second region to be adsorbed into the first capillary structure as much as possible, preventing unabsorbed liquid working fluid from freezing at low temperatures. Once there is no freezing within the heat spreader in a low-temperature environment, the heat spreader shell will not bulge, keeping the heat spreader flat and thus not affecting the heat source in contact with the heat spreader.

[0011] For example, if the branch structure corresponds to the area where the cold source is located, then the branch structure includes at least one branch, which can adsorb the liquid working fluid corresponding to the area where the cold source is located into the first capillary structure as much as possible, so as to prevent the unabsorbed liquid working fluid from freezing at low temperature.

[0012] In one possible implementation, each branch includes at least two sub-branches, and each sub-branch is connected to its parent branch.

[0013] In the scheme shown in this disclosure, each branch can form at least two sub-branches through forking. The more sub-branches and branches there are, the larger the area occupied by the first capillary structure in the second region, and thus the liquid working fluid in the second region can be adsorbed into the first capillary structure as much as possible.

[0014] In one possible implementation, the capillary diameter of the second portion located in the second region is larger than the capillary diameter of the first portion located in the first region.

[0015] Among them, for capillary structures, the smaller the capillary pore size, the greater the capillary force, and the easier it is to adsorb liquid working fluid. However, the smaller the capillary pore size, the greater the backflow resistance of liquid working fluid in the capillary structure, the lower the permeability of the capillary structure, and the less likely the liquid working fluid is to backflow.

[0016] The scheme disclosed herein features a first part with smaller capillary pores, resulting in greater capillary force. This greater capillary force facilitates the adsorption of liquid working fluid, ensuring timely replenishment of the liquid working fluid in the first region. Conversely, the second part has larger capillary pores, leading to higher permeability. This higher permeability reduces the resistance to liquid return, allowing the liquid working fluid to flow back into the first region more easily, thus replenishing it promptly. Once the liquid working fluid in the first region is replenished in a timely manner, a situation where no liquid working fluid is available for evaporation is avoided, ensuring a constant supply of evaporable liquid working fluid in the first region and thereby enhancing the heat dissipation effect of the heat spreader.

[0017] In one possible implementation, on the surface of the first inner surface located within the first region, the projected area of ​​the first portion is greater than the non-projected area, and the non-projected area is greater than zero.

[0018] If the non-projected area is greater than zero, it means that the first part does not completely occupy the surface of the first inner surface in the first region. If the non-projected area is equal to zero, it means that the first part completely occupies the surface of the first inner surface in the first region.

[0019] In one possible implementation, the projected area of ​​the first portion on the surface of the first inner surface located within the first region is equal to the area of ​​the surface of the first portion on the first inner surface located within the first region.

[0020] Wherein, the projected area of ​​the first part on the surface of the first inner surface located in the first region is equal to the area of ​​the surface of the first part on the first inner surface located in the first region, indicating that the non-projected area is equal to zero.

[0021] For example, if the first capillary structure is located directly on the first inner surface, then the area of ​​the first inner surface covered by the first part in the first region is greater than the area not covered by the first part.

[0022] In this way, the first part of the first capillary structure occupies a relatively large area in the first region, which can store a large amount of liquid working fluid. This ensures that the liquid working fluid in the first region is always in a relatively full state, thus avoiding the situation where there is no liquid working fluid available for evaporation in the first region, thereby enhancing the heat dissipation effect of the heat exchanger.

[0023] In addition, for the surface of the first inner surface located in the first region, the projected area of ​​the first part on it is larger than the non-projected area, which makes the area occupied by the first part in the first region relatively large, thereby increasing the adsorption area of ​​the first part for adsorbing liquid working fluid in the first region and also helping to increase the amount of liquid working fluid adsorbed by the first capillary structure in the first region.

[0024] In one possible implementation, the second region corresponds to a cold source, and there are multiple second regions, each containing the second part.

[0025] The solution disclosed herein can transfer the heat absorbed in the first region to multiple second regions for heat dissipation by circulating the working fluid within the shell, thereby enhancing the heat dissipation effect of the heat spreader on the heat source.

[0026] In one possible implementation, the heat spreader includes at least two first capillary structures;

[0027] The first portions of the at least two first capillary structures are all located in the first region, and the second portions of each first capillary structure are respectively located in a second region.

[0028] The scheme disclosed herein has multiple first capillary structures, which enable the arrangement of a second part in each second region.

[0029] In one possible implementation, the first portions of the at least two first capillary structures have overlapping portions in a direction parallel to the first inner surface.

[0030] For example, the first portions of two first capillary structures that are positioned opposite each other have overlapping portions in the first region and in a direction parallel to the first inner surface.

[0031] The scheme disclosed herein features two first capillary structures with overlapping first portions positioned opposite each other. This design facilitates, on the one hand, ensuring that the projected area of ​​the first capillary structure on the surface of the first inner surface within the first region is greater than the non-projected area, thereby increasing the storage capacity of the liquid working fluid within the first region. On the other hand, it allows for the arrangement of a larger number of first capillary structures within the limited space of the heat exchanger.

[0032] In one possible implementation, the first portions of the at least two first capillary structures are spaced apart in a direction parallel to the first inner surface.

[0033] For example, two overlapping first parts are close together but do not touch.

[0034] The scheme shown in this disclosure has multiple first parts located in the first region that are close to each other and spaced apart without contacting each other, which can increase the heat dissipation area in the first region. This is because the liquid working fluid generally evaporates on the outer surface of the first part. Since the multiple first parts do not contact each other, the area of ​​the outer surface in the first region is increased, thus increasing the heat dissipation area in the first region.

[0035] In one possible implementation, a gap exists between the first capillary structure and the second inner surface of the housing, the second inner surface being a surface positioned opposite to the first inner surface.

[0036] The solution disclosed herein has a relatively large thermal resistance in the gap, so the heat transfer between the first capillary structure and the shell wall where the second inner surface is located is relatively weak, and the temperature on the shell wall where the second inner surface is located is not very high. Therefore, the temperature difference between the shell wall where the second inner surface is located and the outer shell of the electronic device is relatively small. Consequently, the user will not feel heat when in contact with the outer shell of the electronic device, thereby enhancing the user's experience of using the electronic device.

[0037] In one possible implementation, the heat spreader further includes a second capillary structure;

[0038] The second capillary structure completely covers the first inner surface. For example, the projected area of ​​the second capillary structure on the first inner surface is equal to the area of ​​the first inner surface.

[0039] The first capillary structure is located on the surface of the second capillary structure, and is a liquid working fluid located in both the first and second capillary structures.

[0040] In the scheme disclosed herein, the first capillary structure can be strip-shaped, and the second capillary structure can be sheet-shaped. The area occupied by the second capillary structure is larger than that occupied by the first capillary structure. Therefore, the liquid working medium adsorbed in the second capillary structure is more than that adsorbed in the first capillary structure. Moreover, the second capillary structure is closer to the heat source. Thus, the second capillary structure can serve as the main heat dissipation structure of the heat spreader, while the first capillary structure serves as an auxiliary heat dissipation structure for the heat spreader. This can enhance the heat dissipation effect of the heat spreader.

[0041] In one possible implementation, the capillary pore diameter of the portion of the second capillary structure in the second region is larger than the capillary pore diameter of the portion in the first region.

[0042] The solution disclosed herein balances the capillary force and permeability of the second capillary structure by having a small capillary pore size in the first region and a large capillary pore size in the second region, thereby enabling the second capillary structure to have a larger capillary force in the first region and a larger permeability in the second region.

[0043] In this way, the liquid working fluid adsorbed by the second capillary structure in the second region can be more easily returned to the first region, and the liquid working fluid can be more easily adsorbed in the first region.

[0044] In one possible implementation, the capillary pore size of the first capillary structure is different from that of the second capillary structure.

[0045] In order to further balance capillary force and permeability, the capillary pore sizes of the first capillary structure and the second capillary structure can be different, as shown in this disclosure.

[0046] For example, the capillary pore size of the first capillary structure can be larger than that of the second capillary structure. Or, for another example, the capillary pore size of the first capillary structure can be smaller than that of the second capillary structure.

[0047] In one possible implementation, the second capillary structure is made of foamed metal.

[0048] Among them, foamed metal can be foamed copper.

[0049] The scheme disclosed herein uses foamed metal as a multi-layered stacked structure. Accordingly, as an example, the material of the first capillary structure can be foamed metal (such as foamed copper). During fabrication, different pore-forming agents can be selected to achieve different capillary pore sizes at different locations within the first capillary structure. For instance, when processing the first capillary structure using foamed metal, a pore-forming agent with a smaller pore size can be selected to process the first part, while a pore-forming agent with a larger pore size can be selected to process the second part. Thus, the capillary pore size of the first part of the processed first capillary structure is smaller than that of the second part.

[0050] In one possible implementation, the first capillary structure is made of foamed metal (such as foamed copper).

[0051] The solution disclosed herein can also be made of foamed metal (such as foamed copper). During fabrication, a second capillary structure comprising both large and small capillary pore sizes can be created using pore-forming agents with varying pore sizes, thereby achieving a portion of the second capillary structure in the second region having a larger capillary pore size than the portion in the first region.

[0052] In one possible implementation, the first capillary structure is a multi-layered stacked structure.

[0053] In one possible implementation, the second capillary structure is a multi-layered stacked structure.

[0054] In one possible implementation, the multi-layer stacked structure is a pre-formed multi-layer stacked structure.

[0055] The solution disclosed herein involves pre-forming the multi-layer stacked structure before processing the heat spreader, and then cutting it into the required shape based on the dimensions of the heat spreader.

[0056] In one possible implementation, the multi-layer stacked structure is processed by one of the following methods: calendering, screen printing, 3D printing, and electroplating.

[0057] Secondly, a heat spreader is also provided, the heat spreader comprising a shell, a first capillary structure, a working fluid, and a third capillary structure; the first capillary structure, the working fluid, and the third capillary structure are all located in the shell, and the area of ​​the projection of the first capillary structure onto the first inner surface of the shell is smaller than the area of ​​the first inner surface; the shell has a cavity; the working fluid switches between a gaseous state and a liquid state, and the liquid working fluid is located in the first capillary structure and the third capillary structure, while the gaseous working fluid is located in the cavity;

[0058] The area within the housing includes a first area and a second area. The first area corresponds to the area where the heat source is located. The second area is different from the first area. The first capillary structure includes a first part and a second part. The first part is located in the first area. The second part and the third capillary structure are both located in the second area, and the second part and the third capillary structure are in contact with or close to each other.

[0059] The scheme disclosed herein includes not only a second part of the first capillary structure but also a third capillary structure within the second region. The capillary structure occupies a large area in the second region, allowing the liquid working fluid within the second region to be adsorbed into the first capillary structure as much as possible, preventing unabsorbed liquid working fluid from freezing at low temperatures. Once there is no freezing within the heat spreader in a low-temperature environment, the heat spreader shell will not bulge, keeping the heat spreader flat and thus not affecting the heat source in contact with the heat spreader.

[0060] In one possible implementation, the heat spreader further includes a second capillary structure;

[0061] The second capillary structure completely covers the first inner surface, and both the first capillary structure and the third capillary structure are located on the surface of the second capillary structure. The liquid working fluid is located in the first capillary structure, the second capillary structure, and the third capillary structure.

[0062] In the scheme disclosed herein, the first and third capillary structures can be strip-shaped, and the second capillary structure can be sheet-shaped. The area occupied by the second capillary structure is greater than the sum of the areas occupied by the first and third capillary structures. Therefore, the liquid working medium adsorbed in the second capillary structure is greater than that adsorbed in the first and third capillary structures. Moreover, the second capillary structure is closer to the heat source. Thus, the second capillary structure can serve as the main heat dissipation structure of the heat spreader, while the first and third capillary structures serve as auxiliary heat dissipation structures for the heat spreader. This enhances the heat dissipation effect of the heat spreader.

[0063] Thirdly, an electronic device is also provided, the electronic device including a heat source and a heat spreader as described in the first or second aspect, wherein a first shell wall of the heat spreader is in contact with the heat source at a position corresponding to the first region, and the first shell wall is the shell wall corresponding to the first inner surface.

[0064] The shell wall corresponding to the first inner surface can be, for example, the shell wall where the first inner surface is located.

[0065] As described above, the vapor chamber of this electronic device has a first capillary structure in the second part of the second region, comprising a main structure and branch structures. The branch structures further include at least one branch. This allows the liquid working fluid in the second region to be adsorbed into the first capillary structure as much as possible, preventing unabsorbed liquid working fluid from freezing at low temperatures. Once there is no freezing within the vapor chamber at low temperatures, the vapor chamber shell will not bulge, keeping the vapor chamber flat and thus not affecting the heat source in contact with it.

[0066] For example, if the branch structure corresponds to the area where the cold source is located, then the branch structure includes at least one branch, which can adsorb the liquid working fluid corresponding to the area where the cold source is located into the first capillary structure as much as possible, so as to prevent the unabsorbed liquid working fluid from freezing at low temperature.

[0067] In addition, since the second part of the first capillary structure in the second region includes the main structure and the branch structure, and the branch structure includes at least one branch, the area occupied by the first capillary structure in the second region can be increased, and the adsorption range of the first capillary structure in the second region can be increased. In this way, it can adsorb liquid working fluid at more or even all positions in the second region, which will further reduce or even eliminate the unadsorbed liquid working fluid in the second region.

[0068] In addition, the first capillary structure adsorbs a large amount of liquid working fluid in the second region, so the liquid working fluid can be replenished to the first region in a timely manner, avoiding the situation where there is no liquid working fluid available for evaporation in the first region, so that the first region always has evaporable liquid working fluid, thereby improving the heat dissipation effect of the heat spreader. Attached Figure Description

[0069] Figure 1 This is a schematic diagram of the cross-section of a heat spreader along the thickness direction provided in this disclosure;

[0070] Figure 2 This is a top view schematic diagram of a heat spreader provided in this disclosure;

[0071] Figure 3 This is a schematic diagram of a first capillary structure located in a shell, as provided in this disclosure;

[0072] Figure 4 This is a schematic diagram showing the relationship between the main structure and branches of the second part of a first capillary structure provided in this disclosure;

[0073] Figure 5 This is a schematic diagram showing the relationship between the main structure and branches of the second part of a first capillary structure provided in this disclosure;

[0074] Figure 6 This is a schematic diagram showing the relationship between the main structure and branches of the second part of a first capillary structure provided in this disclosure;

[0075] Figure 7 This is a schematic diagram showing the relationship between the main structure and branches of the second part of a first capillary structure provided in this disclosure;

[0076] Figure 8 This is a schematic diagram showing the relationship between the main structure and branches of the second part of a first capillary structure provided in this disclosure;

[0077] Figure 9 This is a schematic diagram of a first capillary structure located in a shell, as provided in this disclosure;

[0078] Figure 10 This is a schematic diagram of a first capillary structure and a second capillary structure located in a shell, as provided in this disclosure;

[0079] Figure 11 This is a schematic diagram of the cross-section of a heat spreader along the thickness direction provided in this disclosure;

[0080] Figure 12 This is a schematic diagram of a structure provided in this disclosure, in which a first capillary structure, a third capillary structure, and a second capillary structure are located in a shell.

[0081] Explanation of reference numerals in the attached figures

[0082] 1. Shell; 10. Cavity; 11. First region; 12. Second region; 13. Top cover; 14. Base; 2. First capillary structure; 21. First part; 22. Second part; 221. Main structure; 222. Branch structure; 223. Branch; 224. Sub-branch; 3. Second capillary structure; 4. Third capillary structure. Detailed Implementation

[0083] While the description of this disclosure is presented in conjunction with some embodiments, this does not mean that the features of this application are limited to this embodiment. On the contrary, the purpose of describing the application in conjunction with embodiments is to cover other options or modifications that may arise based on the claims of this disclosure. To provide a thorough understanding of this disclosure, numerous specific details will be included in the following description. This disclosure may also be implemented without using these details. Furthermore, to avoid confusion or obscuring the focus of this disclosure, some specific details will be omitted in the description. It should be noted that, unless otherwise specified, the embodiments and features described in this disclosure can be combined with each other.

[0084] This embodiment provides a vapor chamber (VC), also known as a heat spreader, which mainly includes a shell, a capillary structure, and a working fluid. The shell includes a top cover and a base, which are fixed together to form a sealed vacuum chamber. The capillary structure and the working fluid are both located in the vacuum chamber.

[0085] Among them, capillary structure is a fine structure that exhibits capillary phenomena, which include the phenomenon of wetting liquid rising in a capillary tube and the phenomenon of non-wetting liquid falling in a capillary tube.

[0086] The working medium, for example, can be water.

[0087] In the vacuum chamber of the shell, the working fluid undergoes a phase change at a relatively low temperature. For example, the liquid working fluid can evaporate at a lower temperature and transform into a gaseous working fluid. The gaseous working fluid can condense when cooled and transform into a liquid working fluid.

[0088] In this process, the capillary structure uses capillary action to adsorb the liquid working fluid into it, and the capillary structure does not completely occupy the vacuum chamber, so that there is a cavity in the vacuum chamber, in which the gaseous working fluid can flow.

[0089] Based on the above-mentioned structural features of the heat exchanger, the principle of the heat exchanger for heat source dissipation can be as follows: the first area of ​​the heat exchanger is in contact with the heat source. When the heat source is working, a large amount of heat is generated. The heat is transferred from the heat source to the first area of ​​the heat exchanger, causing the liquid working fluid in the capillary structure to evaporate and transform into a gaseous working fluid. This phase change process can absorb a large amount of heat and dissipate heat for the heat source. Since the liquid working fluid evaporates, the first area can be called the evaporation zone.

[0090] The gaseous working fluid generated in the first region of the heat exchanger flows in the cavity. When the gaseous working fluid flows to the relatively cool second region, it will condense into a liquid in the second region. This phase change process releases heat, releasing the heat absorbed in the first region into the second region. Since the liquid working fluid condenses in the second region, it can be called the condensation zone.

[0091] The liquid working fluid generated in the second region of the heat exchanger is adsorbed in the capillary structure and flows back to the first region through the capillary effect of the capillary structure.

[0092] The above process is repeated continuously in the heat spreader to dissipate heat from the heat source.

[0093] Among them, heat spreaders are widely used in electronic devices, such as mobile phones, laptops and tablets, to dissipate heat from heat sources in electronic devices, such as chips.

[0094] As electronic devices become increasingly thinner, heat spreaders are also becoming thinner. However, reducing the thickness of heat spreaders will face at least the following problems:

[0095] First, the reduced cross-section of the capillary structure increases the resistance to the return flow of the liquid working fluid from the second region to the first region. This causes a large amount of liquid working fluid to accumulate in the second region, resulting in a supersaturated state of the capillary structure there. Unabsorbed liquid working fluid will remain in the second region, and this unabsorbed fluid will freeze at low temperatures, such as in winter. Furthermore, the increased volume of the solid working fluid compared to the liquid, combined with the smaller space of the vapor chamber in the heat spreader, will cause bulging on the outer surface of the heat spreader. Since the outer surface of the heat spreader is in contact with the heat source, this bulging could potentially damage the heat source.

[0096] Secondly, because a large amount of liquid working fluid accumulates in the second region, less liquid working fluid will flow back to the first region. This could lead to the complete evaporation of the liquid working fluid in the first region, causing the circulation of the working fluid in the vacuum chamber to be interrupted and reducing the heat dissipation effect of the heat spreader.

[0097] The heat spreader shown in this embodiment can improve the phenomenon of liquid working fluid accumulation in the second region and improve the heat dissipation effect of the heat spreader.

[0098] like Figure 1 As shown, the heat exchanger includes a shell 1, a first capillary structure 2, and a working fluid, both of which are located within the shell 1. For details on the structure of the shell 1, please refer to [link to relevant documentation]. Figure 1 As shown, it includes an upper cover 13 and a base 14. The upper cover 13 covers the side wall of the base 14 to form a sealed chamber. Then, the sealed chamber is evacuated to form a vacuum chamber.

[0099] In order to form a cavity in the shell 1 for the flow of gaseous working fluid, such as Figure 1 As shown, the area of ​​the projection of the first capillary structure 2 onto the first inner surface a of the housing 1 is smaller than the area of ​​the first inner surface a. The first inner surface a can be the inner surface of a wall of the housing 1, for example, the inner surface of the top cover 13 or the inner surface of the base 14. Figure 1 As shown, the inner surface of the base 14 can be referred to as the first inner surface a, and the inner surface of the top cover 13 can be referred to as the second inner surface b.

[0100] In this way, since the area of ​​the orthographic projection of the first capillary structure 2 on the first inner surface a is smaller than the area of ​​the first inner surface a, a cavity 10 can be formed between the outer surface of the first capillary structure 2 and the inner surface of the shell 1, and the working fluid in the gaseous state can flow in the cavity 10.

[0101] Furthermore, the working fluid undergoes a transformation between a gaseous and a liquid state within the shell 1, allowing both gaseous and liquid working fluids to coexist. The liquid working fluid can reside within the first capillary structure 2, for example, flowing within the first capillary structure 2 by capillary force. The gaseous working fluid can reside within the cavity 10, for example, flowing within the cavity 10.

[0102] See Figure 2 As shown, the area within the casing 1 may include a first region 11 and a second region 12, wherein the first region 11 corresponds to the area where the heat source is located, and the second region 12 is a region different from the first region 11. Figure 2 This is a top view of the vapor chamber structure.

[0103] For example, the second region 12 can be the region corresponding to the cold source, or it can be any region other than the first region 11. For ease of explanation, the second region 12 can be used as an example, with the second region 12 corresponding to the cold source.

[0104] It should be noted that the first region 11 of the heat spreader corresponding to the heat source means that, in application, the position of the first region 11 of the heat spreader is opposite to the position of the heat source. For example, the outer surface of the heat spreader is in close contact with the outer surface of the heat source at the position corresponding to the first region 11. The second region 12 of the heat spreader corresponding to the cold source can mean that, in application, the second region 12 of the heat spreader is adjacent to the cold source, for example, adjacent to a fan.

[0105] In order to use the first capillary structure 2 to return the liquid working medium in the second region 12 to the first region 11, the first capillary structure 2 includes a first part 21 and a second part 22, wherein the first part 21 is located in the first region 11 and the second part 22 is located in the second region 12. The first part 21 and the second part 22 are connected, so that the second part 22 located in the second region 12 can return the adsorbed liquid working medium to the first part 21 located in the first region 11.

[0106] In order to adsorb the liquid working fluid in the second region 12 into the first capillary structure 2 as much as possible, correspondingly, such as Figure 3 As shown, the second part 22 of the first capillary structure 2 located within the second region 12 may include a main structure 221 and a branch structure 222. As described above, the second region 12 may correspond to the region where the cold source is located, and therefore, the main structure 221 and the branch structure 222 may correspond to the region where the cold source is located.

[0107] Since a large portion of the first capillary structure 2 is located within the second region 12, the liquid working fluid within the second region 12 can be adsorbed into the first capillary structure 2 as much as possible, thus preventing the unabsorbed liquid working fluid from freezing at low temperatures.

[0108] In addition, since a large portion of the first capillary structure 2 is located within the second region 12, the area occupied by the first capillary structure 2 within the second region 12 can be increased, thereby increasing the adsorption range of the first capillary structure 2 for adsorbing liquid working fluid within the second region 12. This allows it to adsorb liquid working fluid at more locations within the second region 12, which will further reduce the amount of unadsorbed liquid working fluid within the second region 12.

[0109] In addition, the first capillary structure 2 adsorbs a large amount of liquid working fluid in the second region 12, so that the liquid working fluid can be replenished to the first region 11 in time, avoiding the situation where there is no liquid working fluid available for evaporation in the first region 11, thereby improving the heat dissipation effect of the heat exchange plate.

[0110] In order to ensure that the liquid working fluid adsorbed by the main structure 221 and the branch structure 222 located in the second region 12 can flow back to the first part 21 located in the first region 11, the main structure 221 is connected to the first part 21, and the liquid working fluid adsorbed by the branch structure 222 can flow to the main structure 221. In this way, the liquid working fluid adsorbed by the main structure 221 can flow to the first part 21.

[0111] To ensure that the liquid working fluid adsorbed by the branch structure 222 can be returned to the main structure 221, one possible approach is to refer to... Figure 3 As shown, branch structure 222 can contact the main structure 221. Alternatively, refer to... Figure 4 As shown, the branch structure 222 is close to the main structure 221, so that part or all of the branch structure 222 is located within the adsorption range of the main structure 221, so that the main structure 221 can adsorb the liquid in the branch structure 222.

[0112] In this configuration, branch structure 222 is in contact with the main structure 221, meaning that branch structure 222 is connected to the main structure 221. Branch structure 222 is also close to the main structure 221, meaning that branch structure 222 and main structure 221 are not connected and have a gap between them. For example, the strip-shaped branch structure 222 and the strip-shaped main structure 221 can be parallel or... Figure 4 An angle is shown.

[0113] Regarding the proximity of branch structure 222 to trunk structure 221, for example, Figure 4 As shown, the branch structure 222 is closest to the main structure 221 at position A, satisfying the condition that position A of the branch structure 222 is within the adsorption range of the main structure 221, so that the liquid working fluid adsorbed by the branch structure 222 can be adsorbed by the main structure 221.

[0114] In one example, branch structure 222 includes at least one branch. For example, as... Figure 3 As shown, branch structure 222 includes a branch 223. For example, as... Figures 4 to 6 As shown, branch structure 222 includes two branches 223. For example, as... Figure 7 and Figure 8 As shown, branch structure 222 includes two or more branches 223. See also Figures 3 to 8 As shown, each branch 223 is in contact with or close to the main structure 221.

[0115] As an example, such as Figure 3As shown, the branch structure 222 includes a branch, wherein the main structure 221 and the branch structure 222 can be strip-shaped and can be located side by side within the second region 12. For example, the main structure 221 and the branch structure 222 can be arranged side by side along the width direction of the main structure 221. The main structure 221 and the branch structure 222 can be in contact or have a gap between them.

[0116] As an example, such as Figure 5 and Figure 6 As shown, the main structure 221 is strip-shaped, and the branches 223 of the branch structure 222 can be formed by the main structure 221 undergoing at least one fork near its end.

[0117] For example, such as Figure 5 As shown, the main structure 221 branches once near its end, forming two branches 223. For example, as... Figure 6 As shown, the main structure 221 branches once near the end, forming two branches 223, and each branch 223 branches once more to form two sub-branches 224.

[0118] Therefore, branch 223 may include at least two sub-branches 224, and each sub-branch 224 and its parent branch 223 may be connected or close to each other.

[0119] As an example, such as Figure 7 and Figure 8 As shown, the main structure 221 is strip-shaped, and at least one branch 223 of the branch structure 222 can be located on the side of the main structure 221 along the width direction.

[0120] For example, refer to Figure 7 As shown, multiple branches 223 can be arranged on one side of the main structure 221 along its width direction, and these multiple branches 223 may not contact each other. For example, as... Figure 7 As shown, multiple branches 223 are arranged on both the first and second sides of the main structure 221 along the width direction. For example, as... Figure 8 As shown, the main structure 221 has multiple branches 223 on its side along the width direction, and the branches 223 located on the same side can contact each other.

[0121] In this embodiment, the formation method of at least one branch 223 of the branch structure 222 and its positional relationship relative to the trunk structure 221 are not specifically limited.

[0122] In one example, the parameters affecting the flow of the liquid working fluid in the first capillary structure 2 mainly include the capillary force and permeability of the first capillary structure 2. The greater the capillary force, the better the adsorption effect of the first capillary structure 2, and the easier it is to adsorb the liquid working fluid into it. The higher the permeability, the smaller the backflow resistance of the liquid working fluid in the first capillary structure 2, and the easier it is for it to flow back into the first region 11.

[0123] Both capillary force and permeability are related to the capillary pore size of the first capillary structure 2. For example, the smaller the capillary pore size, the greater the capillary force, but the lower the permeability.

[0124] Therefore, in order to balance the capillary force and permeability of the first capillary structure 2, the capillary pore size of the first part 21 in the first region 11 can be relatively small to increase the capillary force, while the capillary pore size of the second part 22 in the second region 12 can be relatively large to increase the permeability.

[0125] Therefore, the capillary pore diameter of the second part 22 of the first capillary structure 2 can be larger than the capillary pore diameter of the first part 21.

[0126] In this way, the first part 21, with its greater capillary force, more easily adsorbs the liquid working fluid, thus replenishing the liquid working fluid in the first region 11 in a timely manner. Meanwhile, the second part 22, with its greater permeability, reduces the resistance to liquid return, making it easier for the liquid working fluid to flow back into the first region 11, replenishing it promptly. Once the liquid working fluid in the first region 11 is replenished in a timely manner, a situation where there is no liquid working fluid available for evaporation in the first region 11 can be avoided, ensuring that there is always evaporable liquid working fluid in the first region 11, thereby enhancing the heat dissipation effect of the heat spreader.

[0127] In one example, in a scheme where the first region 11 corresponds to a heat source and the second region 12 corresponds to a cold source, there is a transition region between the first region 11 and the second region 12. The transition region can also be called an adiabatic region. In this case, a part of the first capillary structure 2 is also located in the transition region. The capillary pore size of the third part of the first capillary structure 2 in the transition region can also be relatively large to improve the permeability, reduce the return resistance of the liquid working fluid, and replenish the liquid working fluid to the first region 11 in a timely manner.

[0128] For example, the capillary pore size of the portion of the first capillary structure 2 in the transition region can be equal to the capillary pore size of the second portion 22 of the second region 12, both of which are larger than the capillary pore size of the first portion 21 of the first region 11.

[0129] In one example, in order to replenish the liquid working fluid adsorbed by the first capillary structure 2 in the second region to the first region 11 in a timely manner, the third part of the first capillary structure 2 in the transition region can be relatively wide to reduce the backflow resistance of the liquid working fluid, so that the liquid working fluid adsorbed by the first capillary structure 2 in the second region 12 can more easily pass through the transition region and flow back to the first region 11.

[0130] In one example, the liquid working medium adsorbed by the first capillary structure 2 in the first region 11 can also be increased to ensure that the liquid working medium in the first region 11 is sufficient. Accordingly, the first inner surface a includes the surface located in the first region 11 and the surface located in the second region 12. For the surface located in the first region 11, the projected area of ​​the first part 21 on it is greater than the non-projected area, and the non-projected area is greater than or equal to zero.

[0131] If the non-projected area is greater than zero, it means that the first part 21 does not completely occupy the surface of the first inner surface a in the first region 11. If the non-projected area is equal to zero, it means that the first part 21 completely occupies the surface of the first inner surface a in the first region 11.

[0132] For example, if the first capillary structure 2 is located directly on the first inner surface a, then the area of ​​the first inner surface a within the first region 11 covered by the first part 21 is greater than the area not covered by the first part 21.

[0133] In this way, the first capillary structure 2 occupies a relatively large area in the first part 21 of the first region 11, which can store a large amount of liquid working fluid. This ensures that the liquid working fluid in the first region 11 is always in a relatively full state, thereby avoiding the situation where there is no liquid working fluid available for evaporation in the first region 11, and thus enhancing the heat dissipation effect of the heat exchange plate.

[0134] In addition, for the surface of the first inner surface a located in the first region 11, the projected area of ​​the first part 21 on it is larger than the non-projected area, which makes the area occupied by the first part 21 in the first region 11 relatively large, thereby increasing the adsorption area of ​​the first part 21 in the first region 11 for adsorbing liquid working fluid, and also helping to increase the amount of liquid working fluid adsorbed by the first capillary structure 2 in the first region 11.

[0135] In one example, for the surface of the first inner surface a located within the first region 11, the projected area of ​​the first part 21 on it is greater than the non-projected area. One implementation is to make the width of the first part 21 located within the first region 11 wider, that is, to widen the width of the first part 21.

[0136] Another implementation could be to arrange sub-parts around the first part 21, for example, on the side of the first part 21 along its width. The first part 21 and the sub-parts can be in contact or close to each other. If they are close, the liquid working fluid adsorbed by the first part 21 can flow into the sub-parts, allowing the sub-parts to draw liquid working fluid from the second part 22 using the first part 21 as a reference.

[0137] Another implementation method is to have multiple first capillary structures 2, with the first part 21 of each first capillary structure 2 located within the first region 11. This can also increase the area occupied by the first part 21 within the first region 11.

[0138] In one example, in order to enhance the heat dissipation effect of the heat exchanger on the heat source, multiple regions of the heat exchanger are usually associated with the cold source. Accordingly, there can be multiple second regions 12 corresponding to the cold source. The second part 22 of the first capillary structure 2 can be arranged in each second region 12. In this way, by circulating the working fluid in the shell, the heat absorbed in the first region can be transferred to multiple second regions 12 for heat dissipation.

[0139] For example, see Figure 2 As shown, there are two second regions 12, which are located on opposite sides of the first region 11.

[0140] Of course, there can be more second regions 12. For ease of explanation, this embodiment can be illustrated with two second regions 12.

[0141] In one example, multiple second parts 22 may belong to the same capillary structure, for example, such as Figure 3 As shown, the first capillary structure 2 includes a plurality of second portions 22, wherein the number of second portions 22 may be equal to the number of second regions 12.

[0142] In another example, multiple second parts 22 may also belong to different capillary structures, for example, see reference Figure 9 As shown, there are at least two first capillary structures 2. The first part 21 of each of the at least two first capillary structures 2 is located in the first region 11, while the second part 22 of each first capillary structure 2 is located in a second region 12.

[0143] For example, such as Figure 9As shown, there are two second regions 12 and two first capillary structures 2. The first part 21 of both first capillary structures 2 is located in the first region 11, while the second part 22 of one first capillary structure 2 is located in one second region 12, and the second part 22 of the other first capillary structure 2 is located in the other second region 12.

[0144] In one example, the first portions 21 of two first capillary structures 2 that are positioned opposite each other may have overlapping portions within a first region 11 and in a direction parallel to the first inner surface a.

[0145] For example, the first portions 21 of two first capillary structures 2 that are positioned opposite each other have overlapping portions along the width direction of the first portions 21.

[0146] The first portions 21 of the two opposing first capillary structures 2 have overlapping portions. On the one hand, this facilitates the realization that the projected area of ​​the first capillary structure 2 on the surface of the first inner surface a within the first region 11 is larger than the non-projected area, thereby increasing the storage capacity of the liquid working fluid within the first region 11. On the other hand, it facilitates the arrangement of a larger number of first capillary structures 2 within the limited space of the heat exchanger plate.

[0147] In one example, the two overlapping first portions 21 described above can be in contact or close to each other. For example, as Figure 9 As shown, the two first parts 21 are close to each other.

[0148] For example, at least two first portions 21 of the first capillary structure 2 are spaced apart in a direction parallel to the first inner surface a.

[0149] In one example, refer to Figure 9 As shown, multiple first parts 21 located in the first region 11 are arranged at intervals, close to each other but not in contact, which can increase the heat dissipation area in the first region 11. This is because the liquid working fluid generally evaporates on the outer surface of the first part 21. The multiple first parts 21 do not contact each other, which increases the area of ​​the outer surface in the first region 11, thus increasing the heat dissipation area in the first region 11.

[0150] Similarly, by arranging at least one sub-part near the first part 21, the heat dissipation area within the first region 11 can be increased if adjacent sub-parts do not contact each other and the sub-parts do not contact the first part 21.

[0151] In one example, the first capillary structure 2 can be a multi-layered stacked structure, for example, it can be a pre-formed multi-layered stacked structure.

[0152] Among them, the multi-layer stacked structure can increase the number of capillaries in the capillary structure. The more capillaries there are, the greater the adsorption capacity of the capillary structure. Therefore, the first capillary structure 2 adopts a multi-layer stacked structure, which can increase its adsorption capacity.

[0153] Pre-forming means that the multi-layer stacked structure is pre-processed before the heat spreader is processed, and then cut into the required shape based on the size of the heat spreader.

[0154] In one example, multi-layered stacked structures can be achieved through processing methods such as calendering, screen printing, 3D printing, and electroplating.

[0155] Foamed metal is a multi-layered stacked structure, such as foamed copper. Accordingly, in one example, the material of the first capillary structure 2 can be foamed metal. During fabrication, different pore-forming agents can be used to achieve different capillary pore sizes at different locations in the first capillary structure 2. For example, when using foamed metal to process the first capillary structure 2, a pore-forming agent with a smaller pore size can be used to process the first part 21, and a pore-forming agent with a larger pore size can be used to process the second part 22. In this way, the capillary pore size of the first part 21 of the processed first capillary structure 2 is smaller than that of the second part 22.

[0156] Of course, the first capillary structure 2 can also be a multi-layer stacked structure formed by metal mesh (such as copper mesh), a multi-layer stacked structure formed by woven filaments of metal material, a multi-layer stacked structure formed by sintering metal powder (such as copper powder), or a stacked structure formed by metal powder paste (such as copper powder paste).

[0157] In one example, a heat spreader is arranged in an electronic device. The outer surface of the shell wall containing the first inner surface a of the housing is typically in contact with the outer surface of the heat source, while the outer surface of the shell wall containing the second inner surface b of the housing is typically closer to the outer casing of the electronic device, such as the bottom shell. The first inner surface a and the second inner surface b of the housing 1 are positioned opposite each other. To reduce heat transfer between the heat spreader and the outer casing and improve the user experience, a gap may be present between the first capillary structure 2 and the second inner surface b of the housing 1. (See [reference needed]). Figure 10 As shown.

[0158] In this way, because the thermal resistance in the gap is relatively large, the heat transfer between the first capillary structure 2 and the shell wall where the second inner surface b is located is relatively weak, and the temperature on the shell wall where the second inner surface b is located is not very high. Therefore, the temperature difference between the shell wall where the second inner surface b is located and the outer shell of the electronic device is relatively small. Consequently, the user will not feel heat when in contact with the outer shell of the electronic device, thereby enhancing the user experience of using the electronic device.

[0159] The above is a description of the characteristics of the first capillary structure 2 of the heat spreader.

[0160] In another example, to enhance the heat dissipation effect of the vapor chamber, correspondingly, such as Figure 10 and Figure 11 As shown, the heat spreader may further include a second capillary structure 3, which is located on the first inner surface a, and the projected area of ​​the second capillary structure 3 on the first inner surface a is equal to the area of ​​the first inner surface a, that is, the second capillary structure 3 completely covers the first inner surface a. Figure 10 In the diagram, the mesh-filled portion is a schematic representation of the second capillary structure 3 located on the first inner surface a.

[0161] The first capillary structure 2 is located on the surface of the second capillary structure 3, and the liquid working fluid can flow in the first capillary structure 2 and the second capillary structure 3.

[0162] In one example, such as Figure 10 As shown, the first capillary structure 2 can be strip-shaped, and the second capillary structure 3 can be sheet-shaped. The area occupied by the second capillary structure 3 is larger than that occupied by the first capillary structure 2. Therefore, the liquid working medium adsorbed in the second capillary structure 3 is more than that adsorbed in the first capillary structure 2. Moreover, the second capillary structure 3 is closer to the heat source. Therefore, the second capillary structure 3 can serve as the main heat dissipation structure of the heat spreader, while the first capillary structure 2 serves as an auxiliary heat dissipation structure of the heat spreader.

[0163] It should be noted that in the scheme where the heat spreader includes the second capillary structure 3, the first inner surface a is located on the surface of the first region 11, and the projected area of ​​the first part 21 on it is greater than the non-projected area, and the non-projected area is not zero.

[0164] This is because, as mentioned above, a non-projected area greater than zero indicates that the first part 21 does not completely occupy the surface of the second capillary structure 3 in the first region 11, while a non-projected area equal to zero indicates that the first part 21 completely occupies the surface of the second capillary structure 3 in the first region 11. If the first part 21 occupies the entire position of the second capillary structure 3 within the first region 11, then the heat from the heat source will first be transferred to the shell wall where the first inner surface a is located, then to the second capillary structure 3, then to the first capillary structure 2, and then dissipate heat outwards. The heat dissipation path is relatively long, which will reduce the effectiveness of heat dissipation for the heat source. Therefore, in the scheme with the second capillary structure 3, the projected area of ​​the first capillary structure 2 on the surface of the first inner surface a within the first region 11 is smaller than the area of ​​the surface of the first inner surface a within the first region 11. That is, the first part 21 does not completely cover the surface of the second capillary structure 3 within the first region 11.

[0165] In one example, the second capillary structure 3 may include different capillary pore sizes. For example, the capillary pore size of the portion of the second capillary structure 3 within the second region 12 is larger than the capillary pore size of the portion within the first region 11.

[0166] By having a small capillary pore size in the first region 11 and a large capillary pore size in the second region 12, the capillary force and permeability of the second capillary structure 3 can be balanced, so that the second capillary structure 3 has a large capillary force in the first region 11 and a large permeability in the second region 12.

[0167] In this way, the liquid working fluid adsorbed by the second capillary structure 3 in the second region 12 can be more easily returned to the first region 11, and the liquid working fluid can be more easily adsorbed in the first region 11.

[0168] In one example, to further balance capillary force and permeability, the capillary pore sizes of the first capillary structure 2 and the second capillary structure 3 may also be different.

[0169] For example, the capillary pore size of the first capillary structure 2 can be larger than that of the second capillary structure 3. As an example, the second capillary structure 3 can be made of a large-mesh metal mesh (such as a copper mesh), and the first capillary structure 2 can be made of a coarse metal mesh (such as a copper mesh), wherein the larger the mesh size, the smaller the capillary pore size.

[0170] For example, the capillary pore size of the first capillary structure 2 can be smaller than the capillary pore size of the second capillary structure 3.

[0171] In one example, as described above, the first capillary structure 2 can be a multi-layer stacked structure, and the second capillary structure 3 can also be a multi-layer stacked structure, for example, it can be a pre-formed multi-layer stacked structure.

[0172] The processing method for the stacked structure is similar to that described above, and will not be listed here again.

[0173] Similarly, the material of the second capillary structure 3 can also be foamed metal, such as foamed copper. In the manufacturing process, it can also be processed into a second capillary structure 3 including large capillary pore diameters and small capillary pore diameters by using pore-forming agents with different pore sizes, so that the capillary pore diameter of the portion of the second capillary structure 3 in the second region 12 is larger than the capillary pore diameter of the portion in the first region 11.

[0174] Of course, the second capillary structure 3 can also be a multi-layered stacked structure formed by metal mesh (such as copper mesh), a multi-layered stacked structure formed by woven filaments of metal material, a multi-layered stacked structure formed by sintering metal powder (such as copper powder), or a stacked structure formed by metal powder paste (such as copper powder paste).

[0175] Based on the above, one structure of the heat spreader may include a first capillary structure located on the first inner surface a of the housing 1. Another structure of the heat spreader may include a first capillary structure and a second capillary structure, wherein the second capillary structure is sheet-like and laid on the first inner surface a, and the area of ​​the second capillary structure is equal to the area of ​​the first inner surface a; the first capillary structure is strip-like and located on the surface of the second capillary structure.

[0176] Taking the latter structure of the vapor chamber as an example, in the process of dissipating heat from the heat source, the liquid working fluid adsorbed by the first and second capillary structures in the first region undergoes a phase change upon heating, evaporating into a gaseous working fluid. The gaseous working fluid flows to the second region, where it cools and condenses back into a liquid working fluid. The liquid working fluid is then adsorbed by the first and second capillary structures in the second region and, under the action of capillary force, flows back into the first and second capillary structures in the first region, awaiting another phase change and evaporation to become a gaseous working fluid. This cycle continues, dissipating heat from the heat source.

[0177] In this embodiment, the second part of the first capillary structure within the second region includes a main structure and a branch structure, with the branch structure including at least one branch. This allows the liquid working fluid within the second region to be adsorbed into the first capillary structure as much as possible, preventing unabsorbed liquid working fluid from freezing at low temperatures. Once there is no freezing within the heat spreader in a low-temperature environment, the heat spreader shell will not bulge, keeping the heat spreader flat and thus not affecting the heat source in contact with the heat spreader.

[0178] For example, if the branch structure corresponds to the area where the cold source is located, then the branch structure includes at least one branch, which can adsorb the liquid working fluid corresponding to the area where the cold source is located into the first capillary structure as much as possible, so as to prevent the unabsorbed liquid working fluid from freezing at low temperature.

[0179] In addition, since the second part of the first capillary structure in the second region includes the main structure and the branch structure, and the branch structure includes at least one branch, the area occupied by the first capillary structure in the second region can be increased, and the adsorption range of the first capillary structure in the second region can be increased. In this way, it can adsorb liquid working fluid at more or even all positions in the second region, which will further reduce or even eliminate the unadsorbed liquid working fluid in the second region.

[0180] In addition, the first capillary structure adsorbs a large amount of liquid working fluid in the second region, so the liquid working fluid can be replenished to the first region in a timely manner, avoiding the situation where there is no liquid working fluid available for evaporation in the first region, so that the first region always has evaporable liquid working fluid, thereby improving the heat dissipation effect of the heat spreader.

[0181] This embodiment also provides a heat spreader, such as Figure 12 As shown, the heat spreader also includes a shell 1, a first capillary structure 2, and a working fluid. In addition, it also includes a third capillary structure 4. The first capillary structure 2, the working fluid, and the third capillary structure 4 are all located in the shell 1. The area of ​​the projection of the first capillary structure 2 on the first inner surface a of the shell 1 is smaller than the area of ​​the first inner surface a, so that a cavity 10 can be formed inside the shell 1. The working fluid in liquid state is located in the first capillary structure 2 and the third capillary structure 4, and the working fluid in gaseous state is located in the cavity 10.

[0182] The area inside the shell 1 includes a first region 11 and a second region 12. The first region 11 corresponds to the heat source, and the second region 12 is different from the first region 11. The first capillary structure 2 includes a first part 21 located in the first region 11 and a second part 22 located in the second region 12. The third capillary structure 4 is located in the second region 12 and is used to flow the adsorbed liquid working fluid to the first region 11.

[0183] In one example, the structure of the housing 1 can be referred to the above description, and will not be repeated here. The features of the first capillary structure 2 can be as follows: Figure 12 The structural features shown can also possess the features of the first capillary structure 2 described above.

[0184] like Figure 12 As shown, the second region not only contains the second part of the first capillary structure but also a third capillary structure. The capillary structure occupies a large area in the second region, which allows the liquid working fluid in the second region to be adsorbed into the first capillary structure as much as possible, preventing the unabsorbed liquid working fluid from freezing at low temperatures. Once there is no freezing inside the heat spreader in a low-temperature environment, the shell of the heat spreader will not bulge, keeping the heat spreader flat and thus not affecting the heat source in contact with the heat spreader.

[0185] In one example, the third capillary structure and the second part are in contact or close proximity, so that the liquid working fluid adsorbed by the third capillary structure can flow back to the first part in the first region through the second part.

[0186] In one example, the heat spreader may further include a second capillary structure 3, wherein the characteristics of the second capillary structure 3 are as described above. Figure 12 As shown, the second capillary structure 3 is located on the first inner surface a, and the projected area of ​​the second capillary structure 3 on the first inner surface a is equal to the area of ​​the first inner surface a, that is, the second capillary structure 3 covers the entire area of ​​the first inner surface a. Figure 12 In the diagram, the mesh-filled portion is a schematic representation of the second capillary structure 3 located on the first inner surface a.

[0187] The first capillary structure 2 and the third capillary structure 4 are both located on the surface of the second capillary structure 3, and the liquid working fluid can flow in the first capillary structure 2, the third capillary structure 4 and the second capillary structure 3.

[0188] The features of the second capillary structure 3 can be found above, and will not be repeated here.

[0189] This embodiment also provides an electronic device, which may be a mobile phone, a laptop computer, or a tablet computer, etc. The electronic device includes a heat source and the aforementioned heat spreader. The outer surface of the first shell wall of the heat spreader is in contact with the outer surface of the heat source at a position corresponding to the first region. The first shell wall is the shell wall corresponding to the first inner surface a, for example, the shell wall where the first inner surface is located.

[0190] In one example, thermal interface materials (TIM) can also be filled between the first shell wall of the heat spreader and the heat source to eliminate the contact gap between the heat spreader and the heat source, enhance the heat transfer between the two, and improve the heat dissipation effect for the heat source.

[0191] In one example, the electronic device may also include a cold source, which may be a fan, and a second area of ​​the heat spreader may be adjacent to the fan to absorb the heat released by condensation in the second area through air cooling.

[0192] As described above, the vapor chamber of this electronic device has a first capillary structure in the second part of the second region, comprising a main structure and branch structures. The branch structures further include at least one branch. This allows the liquid working fluid in the second region to be adsorbed into the first capillary structure as much as possible, preventing unabsorbed liquid working fluid from freezing at low temperatures. Once there is no freezing within the vapor chamber at low temperatures, the vapor chamber shell will not bulge, keeping the vapor chamber flat and thus not affecting the heat source in contact with it.

[0193] For example, if the branch structure corresponds to the area where the cold source is located, then the branch structure includes at least one branch, which can adsorb the liquid working fluid corresponding to the area where the cold source is located into the first capillary structure as much as possible, so as to prevent the unabsorbed liquid working fluid from freezing at low temperature.

[0194] In addition, since the second part of the first capillary structure in the second region includes the main structure and the branch structure, and the branch structure includes at least one branch, the area occupied by the first capillary structure in the second region can be increased, and the adsorption range of the first capillary structure in the second region can be increased. In this way, it can adsorb liquid working fluid at more or even all positions in the second region, which will further reduce or even eliminate the unadsorbed liquid working fluid in the second region.

[0195] In addition, the first capillary structure adsorbs a large amount of liquid working fluid in the second region, so the liquid working fluid can be replenished to the first region in a timely manner, avoiding the situation where there is no liquid working fluid available for evaporation in the first region, so that the first region always has evaporable liquid working fluid, thereby improving the heat dissipation effect of the heat spreader.

[0196] The above description is only one embodiment of this disclosure and is not intended to limit this disclosure. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this disclosure should be included within the protection scope of this disclosure.

Claims

1. A vapor chamber, characterized by, The heat plate comprises a shell (1), a first capillary structure (2) and a working medium; The first capillary structure (2) and the working medium are located in the shell (1), and the area of the projection of the first capillary structure (2) on the first inner surface (a) of the shell (1) is smaller than the area of the first inner surface (a), the shell (1) has a cavity (10) therein, the working medium is converted between gaseous and liquid states, and the working medium in liquid state is located in the first capillary structure (2), and the working medium in gaseous state is located in the cavity (10); The area in the shell (1) comprises a first area (11) and a second area (12), the first area (11) is a region corresponding to a heat source, the second area (12) is different from the first area (11), the first capillary structure (2) comprises a first part (21) located in the first area (11) and a second part (22) located in the second area (12), the second part (22) comprises a trunk structure (221) and a branch structure (222), the trunk structure (221) is connected with the first part (21), the branch structure (222) corresponds to a region where a cold source is located, and the branch structure (222) comprises at least one branch (223), each branch (223) is in contact with or close to the trunk structure (221).

2. The vapor chamber of claim 1, wherein Each branch (223) comprises at least two sub-branches (224), and each sub-branch (224) is connected with the branch (223) to which the sub-branch (224) belongs.

3. The vapor chamber of claim 1, wherein The capillary pore diameter of the second part (22) located in the second area (12) is greater than the capillary pore diameter of the first part (21) located in the first area (11).

4. The vapor chamber of claim 1, wherein On the surface of the first inner surface (a) located in the first area (11), the projected area of the first part (21) is greater than the non-projected area, and the non-projected area is greater than zero.

5. The vapor chamber according to any one of claims 1 to 3, wherein The projected area of the first part (21) on the surface of the first inner surface (a) located in the first area (11) is equal to the area of the surface of the first inner surface (a) located in the first area (11).

6. The vapor chamber of claim 1, wherein The number of the second areas (12) is multiple, and the second part (22) is arranged in each second area (12).

7. The vapor chamber of claim 6, wherein The heat plate comprises at least two first capillary structures (2); The first parts (21) of the at least two first capillary structures (2) are located in the first area (11), and the second parts (22) of the first capillary structures (2) are respectively located in the second areas (12).

8. The vapor chamber of claim 7, wherein The first parts (21) of the at least two first capillary structures (2) have an overlapping part in the direction parallel to the first inner surface (a).

9. The vapor chamber of claim 7, wherein The first parts (21) of the at least two first capillary structures (2) are arranged in a spaced manner in the direction parallel to the first inner surface (a).

10. The vapor chamber of claim 1, wherein The first capillary structure (2) and a second inner surface (b) of the housing (1) have a gap, the second inner surface (b) is an inner surface opposite to the first inner surface (a).

11. The vapor chamber of any one of claims 1-4, or 6-10, wherein: The vapor chamber further comprises a second capillary structure (3); The second capillary structure (3) completely covers the first inner surface (a); The first capillary structure (2) is located on the surface of the second capillary structure (3), and the working medium in liquid state is located in the first capillary structure (2) and the second capillary structure (3).

12. The vapor chamber of claim 11, wherein, The capillary pore diameter of the part of the second capillary structure (3) in the second region (12) is greater than the capillary pore diameter of the part in the first region (11).

13. The vapor chamber of claim 11, wherein, The capillary pore diameter of the first capillary structure (2) is different from the capillary pore diameter of the second capillary structure (3).

14. The vapor chamber of claim 11, wherein, The material of the second capillary structure (3) is foam metal.

15. The vapor chamber of claim 1, wherein, The material of the first capillary structure (2) is foam metal.

16. The vapor chamber of claim 1, wherein The first capillary structure (2) is a multi-layer stacked structure.

17. The vapor chamber of claim 11, wherein, The second capillary structure (3) is a multi-layer stacked structure.

18. The vapor chamber of claim 16, wherein, The multi-layer stacked structure is preformed.

19. The vapor chamber of claim 16, wherein, The processing mode of the multi-layer stacked structure is one of calendering, silk printing, 3D printing and electroplating.

20. An electronic device, comprising: The electronic device comprises a heat source and the vapor chamber of any one of claims 1 to 19, a first housing wall of the vapor chamber is in contact with the heat source at a position corresponding to the first region (11), and the first housing wall is a housing wall corresponding to the first inner surface (a).

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