Patent Publication Number: US-2023144108-A1

Title: Vapor chamber device

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a divisional application of and claims the priority benefit of U.S. application Ser. No. 16/782,020, filed on Feb. 4, 2020, which claims the priority benefit of Taiwan application serial no. 108145459, filed on Dec. 12, 2019. The entirety of each of the above-mentioned patent applications is hereby incorporated by reference herein and made a part of this specification. 
    
    
     BACKGROUND 
     Technical Field 
     The disclosure relates to a vapor chamber device, and in particular, to a high-efficacy vapor chamber device. 
     Description of Related Art 
     A vapor chamber is a common heat sink. The vapor chamber mainly includes a flat sealed casing, a capillary tissue formed in the flat sealed casing, and working fluid filling the flat sealed casing. The flat sealed casing contacts a heat source, e.g., a central processing unit (CPU), and dissipates heat for the heat source through a vapor-liquid phase change of the working fluid in the vapor chamber. How to improve heat dissipation capacity of the vapor chamber is to be researched in the field. 
     SUMMARY 
     The disclosure provides a vapor chamber device having a favorable heat dissipation effect. 
     A vapor chamber device provided in one embodiment of the disclosure includes working fluid and is adapted to be thermally coupled to a heat source. The vapor chamber device includes a first casing and a second casing. The first casing includes a first plate, a first capillary structure at an inner surface of the first plate, and a first lateral wall protruding from the inner surface and surrounding the first capillary structure, where the heat source is adapted to be in contact with an outer surface of the first plate. The second casing is stacked on the first casing and includes a second plate, a plurality of supporting posts protruding from the second plate, and a second lateral wall protruding from the second plate and surrounding the supporting posts, where a plurality of vapor channels are formed between the supporting posts. The supporting posts face towards the first capillary structure, and the first lateral wall is connected to the second lateral wall. The vapor chamber device further includes a second capillary structure and a third capillary structure. The second capillary structure is disposed between the first capillary structure and the supporting posts of the second casing. The third capillary structure is disposed in an area which is at the inner surface of the first plate and corresponds to the heat source. 
     In an embodiment of the disclosure, the first capillary structure includes a plurality of trenches formed between a plurality of protruding bars, and an area which is in the trenches and corresponds to the heat source is filled with the third capillary structure. 
     In an embodiment of the disclosure, the second capillary structure is a mesh structure woven by a plurality of wires and includes a plurality of holes, and the holes corresponding to the heat source and the trenches of the first capillary structure are filled with the third capillary structure. 
     In an embodiment of the disclosure, the second capillary structure has an opening corresponding to the heat source, and the opening and the trenches of first capillary structure are filled with the third capillary structure. 
     In an embodiment of the disclosure, the first plate has a cavity corresponding to the heat source, the first capillary structure is located outside the cavity, and the cavity is filled with the third capillary structure. 
     In an embodiment of the disclosure, the second capillary structure is a mesh structure woven by a plurality of wires and includes a plurality of holes, and the holes corresponding to the heat source are filled with the third capillary structure. 
     In an embodiment of the disclosure, the second capillary structure has an opening corresponding to the heat source, and the opening is filled with the third capillary structure. 
     In an embodiment of the disclosure, the supporting posts are evenly distributed on the second plate, and a cross-shaped vapor flow channel is formed between the supporting posts. 
     In an embodiment of the disclosure, the supporting posts include a plurality of first supporting posts and a plurality of second supporting posts, a shape of the first supporting post is different from the shape of the second supporting post, the first supporting posts are disposed corresponding to the heat source, and the second supporting posts are located beside the first supporting posts and extend along an axial direction. A cross-shaped vapor flow channel is formed between the supporting posts. 
     In an embodiment of the disclosure, one portion of the supporting posts is disposed corresponding to the heat source, the other portion of the supporting posts is radially arranged around the one portion of the supporting posts as a center, and a cross-shaped vapor flow channel is formed between the supporting posts. 
     In an embodiment of the disclosure, the supporting posts include a plurality of rectangular posts, a plurality of conical posts, a plurality of trapezoidal posts, a plurality of cylinders, or a plurality of irregular posts. 
     In an embodiment of the disclosure, the first capillary structure includes a plurality of trenches, and at least some of the trenches are radially arranged. 
     In an embodiment of the disclosure, the third capillary structure includes metal powders or non-woven metal wool. 
     Based on the above, for the vapor chamber device of the disclosure, in addition to the first capillary structure and the second capillary structure disposed between the first casing and the second casing to improve heat dissipation efficiency, the third capillary structure is further disposed in an area which is at the inner surface of the first plate and corresponds to the heat source. With the third capillary structure, the liquid disposed in the vapor chamber device may be subject to a greater capillary force, the trenches that are in the first capillary structure and that are covered by the second capillary structure have lower flow resistance, and the liquid may be more quickly supplemented to the area corresponding to the heat source, so as to improve the anti-drying capability of the area. Therefore, a sufficient amount of liquid may be maintained in the area for phase changes, and the drying tendency in the area may be reduced. Thereby, the vapor chamber device provided in one or more embodiments of the disclosure may have a better heat dissipation effect. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1 A  is a schematic diagram of an appearance of a vapor chamber device according to an embodiment of the disclosure. 
         FIG.  1 B  is a schematic cross-sectional view of the vapor chamber device taken along line A-A of  FIG.  1 A . 
         FIG.  1 C  is a schematic cross-sectional view of the vapor chamber device taken along line B-B of  FIG.  1 A . 
         FIG.  1 D  is a schematic diagram of an inner surface of a second casing of the vapor chamber device of  FIG.  1 A . 
         FIG.  1 E  is a schematic cross-sectional view of a vapor chamber device according to another embodiment of the disclosure. 
         FIG.  2 A  and  FIG.  2 B  are schematic diagrams of a second casing of a plurality of vapor chamber devices according to other embodiments of the disclosure. 
         FIG.  2 C  is a schematic diagram of an inner surface of a first casing of a vapor chamber device according to other embodiments of the disclosure. 
         FIG.  3    is a schematic diagram of a vapor chamber device according to another embodiment of the disclosure. 
         FIG.  4    is a schematic diagram of a vapor chamber device according to another embodiment of the disclosure. 
         FIG.  5    is a schematic diagram of a vapor chamber device according to another embodiment of the disclosure. 
     
    
    
     DESCRIPTION OF THE EMBODIMENTS 
       FIG.  1 A  is a schematic diagram of an appearance of a vapor chamber device according to an embodiment of the disclosure. However, the shape of the appearance is not limited to a square plate shape and may be any shape.  FIG.  1 B  is a schematic cross-sectional view of the vapor chamber device taken along line A-A of  FIG.  1 A .  FIG.  1 C  is a schematic cross-sectional view of the vapor chamber device taken along line B-B of  FIG.  1 A . 
     With reference to  FIG.  1 A  to  FIG.  1 C , a vapor chamber device  100  of the present embodiment is adapted to be thermally coupled to a heat source  10  ( FIG.  1 B ). The heat source  10  is, for example, a central processing unit of a main board, but the heat source  10  may also be other chips, and the type and quantity of heat sources  10  are not limited thereto. The vapor chamber device  100  includes a first casing  110  and a second casing  120 . As shown in  FIG.  1 B , the first casing  110  includes a first plate  111 , a first capillary structure  113  at an inner surface  1112  of the first plate  111 , and a first lateral wall  117  protruding from the inner surface  1112  and surrounding the first capillary structure  113 . The heat source  10  is adapted to be in contact with an outer surface  1114  of the first casing of the first plate  111 , and heat energy generated by the heat source  10  is transferred to the vapor chamber device  100 . 
     As shown in  FIG.  1 B  and  FIG.  1 C , the first capillary structure  113  includes a plurality of trenches  114  formed between a plurality of protruding bars  112 . More specifically, the protruding bars  112  protrude from the inner surface  1112  of the first plate, so that trenches  114  are defined between two adjacent protruding bars  112 . The design of the first capillary structure  113  using the trenches  114  may provide a smaller flow resistance. In the present embodiment, a width of the trench  114  is, for example, between 50 μm and 200 μm, and a depth of the trench  114  is, for example, between 50 μm and 200 μm, but the width and the depth of the trench  114  are not limited thereto. However, capillary force of a simple open trench is insufficient, and the simple open trench is not suitable for a non-horizontal vapor chamber device working against gravity. However, if a second capillary structure  130  is covered with a layer of mesh, it may not only maintain the advantage of low flow resistance of the trench, but also significantly improve capillary force, so that the vapor chamber device is adapted to be placed against gravity. If non-woven metal wool or metal powders with stronger capillary force are further added to the capillary structure near the heat source  10 , the capillary force there may further be enhanced, and the anti-drying capability may be improved. 
     Therefore, as shown in  FIG.  1 B , the vapor chamber device  100  further includes a second capillary structure  130  and a third capillary structure  140  disposed near the corresponding heat source  10 . The second capillary structure  130  is disposed between the first capillary structure  113  and supporting posts  122 , to cover the first capillary structure  113  and strengthen the capillary and channel functions of the first capillary structure  113 . The third capillary structure  140  is only disposed in the capillary structure near a position corresponding to the heat source  10 , and does not block a path through which liquid passes when flowing back. 
     In addition, in the present embodiment, the first plate  111  and the protruding bars  112  are integrally formed, and such a design may have a relatively simple structure. Since there is no thermal contact resistance between the first plate  111  and the protruding bars  112  (that is, between the first plate  111  and the trenches  114 ), the heat transfer effect is better. 
     The second casing  120  is stacked on the first casing  110  and includes a second plate  121 , a plurality of supporting posts  122  protruding from the second plate  121 , and a second lateral wall  128  protruding from the second plate  121  and surrounding the supporting posts  122 . In the present embodiment, the supporting posts  122  are flush with the second lateral wall  128 , but a relationship between the supporting posts  122  and the second lateral wall  128  is not limited thereto. 
       FIG.  1 D  is a schematic diagram of an inner surface of a second casing of the vapor chamber device of  FIG.  1 A . With reference to  FIG.  1 D , in the present embodiment, shapes of the supporting posts  122  are uniformly and evenly distributed on the inner surface of the second plate  121 , and a plurality of vapor channels  124  is formed between the supporting posts  122 . 
     The supporting posts  122  are, for example, square posts, but in other embodiments, the supporting posts  122  may also be rectangular posts, cylinders, elliptical posts, polygonal posts, tapered posts, irregular posts, or/and a combination thereof. Shapes and forms of distribution of the supporting posts  122  are not limited thereto. The supporting posts  122  are integrally formed with the second plate  121 , but may alternatively be joined through other manners such as welding and depositing. 
       FIG.  1 E  is a schematic cross-sectional view of a vapor chamber device according to another embodiment of the disclosure. Cross-sectional shapes of supporting posts  122 ′ of a vapor chamber device  100 ′ are inverted trapezoids, and therefore a cross-sectional shape of a constructed vapor channel  124 ′ is trapezoidal. In other embodiments, the supporting posts  122 ′ include a plurality of rectangular posts, a plurality of conical posts, a plurality of trapezoidal posts, a plurality of cylinders, or a plurality of irregular posts. Therefore, the cross-sectional shapes of the supporting posts  122 ′ may be triangles, arcs, or other shapes. Similarly, the cross-sectional shape of the vapor channel  124 ′ may be a triangle, an arc, or other shapes. 
     Returning to  FIG.  1 B , in the present embodiment, the supporting posts  122  face the first capillary structure  113 . In addition, in the present embodiment, the first casing  110  and the second casing  120  are, for example, two metal casings, and the first lateral wall  117  is engaged with the second lateral wall  128  to provide favorable structural strength. A manner in which the first lateral wall  117  and the second lateral wall  128  is, for example, diffusion bonding or brazing, which should however not be construed as a limitation in the disclosure. 
     In the present embodiment, the first capillary structure  113  is slightly lower than the first lateral wall  117 , and when the second capillary structure  130  is approximately flush with the first lateral wall  117  when being disposed on the first capillary structure  113 , so that when the first lateral wall  117  is engaged with the second lateral wall  128 , the supporting posts  122  may abut against the second capillary structure  130 . Definitely, in other embodiments, the foregoing height relationship is not limited thereto. 
     It should be noted that, in the present embodiment, an appropriate amount of working fluid g such as water fills inner space surrounded by the first casing  110  and the second casing  120 , but the type of the working fluid g is not limited thereto. For example, the working fluid g flows in the trench  114  of the first capillary structure  113  of the first casing  110  in a form of liquid. The working fluid g absorbs heat in an area close to the heat source  10  and evaporates into vapor. 
     Therefore, in the present embodiment, the supporting posts  122  abut against the second capillary structure  130 , and may support the second plate  121 , which may effectively prevent the first casing  110 , the second casing  120 , and the vapor channel  124  from being collapsed during evacuating. In addition, when the working fluid g is condensed into liquid from vapor, the working fluid g may also flow down along a lateral wall of the supporting post  122 . In other words, the supporting posts  122  may also serve as a structure for guiding the working fluid g (liquid) to flow down. 
     In the present embodiment, the second capillary structure  130  is a mesh structure woven by a plurality of wires  132 , such as a copper mesh. Definitely, in other embodiments, the second capillary structure  130  may also be a non-woven mesh or a porous metal foam capillary structure, and the form of the second capillary structure  130  is not limited thereto. 
     It is worth mentioning that in  FIG.  1 B , since the second capillary structure  130  is disposed on the trenches  114  of the first capillary structure  113 , tops of the trenches  114  of the first capillary structure  113  are covered by the second capillary structure  130 . However, a similar capillary structure is formed in a direction (a direction of emitting or injecting into the drawing surface) in which the trenches  114  extend, and the structure may enable the working fluid g in the trenches  114  to resist gravity and allow the vapor chamber device  100  to complete thermal cycle well under a non-horizontal condition. 
     In addition, in the present embodiment, the third capillary structure  140  is disposed in an area that is at the inner surface  1112  of the first plate  111  and that corresponds to the heat source  10 . In particular, in the present embodiment, since the trenches  114  of the first capillary structure  113  are evenly distributed on the first plate  111 , some (especially a central trench) of the trenches  114  correspond to the area that is on the first plate  111  and that corresponds to the heat source  10 . Therefore, in the present embodiment, an area that is in the trenches  114  and corresponds to the heat source  10  is filled with the third capillary structure  140 . 
     As shown in  FIG.  1 C , the second capillary structure  130  includes a plurality of holes  134 . It should be noted that, in a cross section of  FIG.  1 B , wires  132  of the second capillary structure  130  are just cut, and the holes  134  cannot be seen. In a cross section of  FIG.  1 C , a relationship between the wires  132  of the second capillary structure  130  and the holes  134  may be observed. In addition, the cross section of  FIG.  1 C  is just cut along one of the trenches  114  of the first capillary structure  113 , and the protruding bars  112  cannot be seen in this section. The supporting posts  122  of the second casing  120  are not cut in  FIG.  1 C , and only the vapor channel  124  is shown. 
     The holes  134  corresponding to the heat source  10  are filled with the third capillary structure  140 . In the present embodiment, a sintered capillary structure is taken as an example of the third capillary structure  140 . For example, metal powders are sintered in a local area of the trenches  114  and the holes  134 . Definitely, in other embodiments, the form of the third capillary structure  140  is not limited thereto. In addition, in an embodiment that is not illustrated, the second capillary structure  130  may also be a metal foam layer with a large number of holes inside, and the holes of the metal foam layer and the trenches  114  of the first capillary structure  113  are filled with the third capillary structure  140  (metal powders). 
     As shown in  FIG.  1 C , the outer surface  1114  (marked in  FIG.  1 B ) of the first casing  110  of the vapor chamber device  100  is in contact with the heat source  10 , heat generated by the heat source  10  is transferred to the first casing  110 . An area that is of the vapor chamber device  100  and that corresponds to the heat source  10  is referred to as an evaporation area. In the evaporation area, the liquid in the trenches  114  absorbs heat and vaporizes into vapor. The working fluid g (vapor) flows upward to the vapor channel  124  of the second casing  120  and diffuse into an internal vapor cavity of the second casing  120 , further condenses into a liquid in the condensing area (for example, the outer surface  129  of the second casing of the vapor chamber plate, or a selected area of the outer surface  1114  of the first casing that is not in contact with the heat source  10 ) of the vapor chamber plate, and the heat is discharged from the vapor chamber device  100 . The condensed working fluid g (liquid) flows down to the trench  114  of the first casing  110  and flows through the trench  114  to the third capillary structure  140  to complete a cycle. 
     It is worth mentioning that, in the present embodiment, the trenches  114  of the first capillary structure  113  and the holes  134  of the second capillary structure  130  in the evaporation area are filled with the third capillary structure  140 . Since the third capillary structure  140  provides strong capillary force, the working fluid g may be easily sucked into the evaporation area, to avoid a case that the vaporized liquid in the evaporation area cannot be supplemented in time, thereby providing good anti-drying capability. In addition, the trenches  114  of the first capillary structure  113  and the holes  134  of the second capillary structure  130  are not provided with a third capillary structure  140  outside an area corresponding to the heat source  10 , so that a low flow resistance may be maintained. 
     In this way, the foregoing design of the vapor chamber device  100  may greatly increase the maximum heat dissipation amount without increasing the thickness (the thickness of the first capillary structure  113  and the second capillary structure  130  may be maintained), and may be applied to a thin device. Through testing, in comparison with the vapor chamber without the third capillary structure  140 , the maximum heat dissipation amount of the vapor chamber device  100  of the present embodiment may be increased by at least  50 %, so that the vapor chamber device has improved performance. 
     The working fluid evaporates in the capillary structure close to the heat source, and the formed vapor passes through the cross-shaped vapor flow channel formed between the plurality of supporting posts of the second plate, diffuses to the vapor cavity inside the entire vapor chamber, and further condenses into a liquid in the condensing area of the vapor chamber, and the heat is discharged from the vapor chamber device. The condensed liquid passes through the capillary structure below, flows back to the area near the heat source, and evaporates, to complete a thermal cycle. Since the third capillary structure corresponding to the heat source area has stronger capillary force, and the trenches that are in the first capillary structure and that are covered by the second capillary structure have both lower flow resistance and stronger capillary force, the three capillary structures are properly matched, so that the working fluid may flow back to the evaporation area near the heat source more quickly, and the evaporation area of the vapor chamber device is less easier to dry out and has more favorable heat dissipation efficiency. 
     A vapor chamber device in another pattern or a second casing thereof is described below. Same or similar elements as the previous embodiment are denoted by same or similar symbols. The descriptions thereof are omitted herein, and only main differences are described. 
       FIG.  2 A  and  FIG.  2 B  are schematic diagrams of a second casing of a plurality of vapor chamber devices according to other embodiments of the disclosure. With reference to  FIG.  2 A  first, a main difference between the second casing  120   a  of  FIG.  2 A  and the second casing  120  of  FIG.  1 D  is that, in the present embodiment, these supporting posts include a plurality of first supporting posts  122   a  and a plurality of second supporting posts  123 , and a shape of the first supporting post  122   a  is different from a shape of the second supporting post  123 . The first supporting posts  122   a  are disposed corresponding to the heat source  10 , and the second supporting posts  123  are located beside the first supporting posts  122   a  and extend along an axial direction A 1 . 
     In the present embodiment, the second casing  120   a  is provided with densely populated first supporting posts  122   a  corresponding to the heat source  10 , so as to provide good structural strength. The second supporting posts  123  are disposed on both sides of the first supporting posts  122   a  and extend along the axial direction A 1  to guide a flow direction of the working fluid g (vapor). 
     With reference to  FIG.  2 B , a main difference between the second casing  120 b of  FIG.  2 B  and the second casing  120   a  of  FIG.  2 A  is that, in the present embodiment, one portion (the first supporting posts  122   a ) of these supporting posts is disposed corresponding to the heat source  10 , and the other portion of the supporting posts (the second supporting posts  123 ,  125 , and  127 ) is radially arranged around the first supporting posts  122   a  as a center. Such a design may also well guide the flow direction of the working fluid g (vapor). 
       FIG.  2 C  is a schematic diagram of an inner surface of a first casing of a vapor chamber device according to other embodiments of the disclosure. With reference to  FIG.  2 C , in the present embodiment, the first casing  110 ″ has trenches  114 ,  112 ″,  115 ,  118 , and  119  with a plurality of different directions, and the trenches are radial to reduce the flow resistance and allow the condensed liquid to flow back quickly. The arrangement pattern of the trenches on the inner surface of the first casing is not limited to a radial pattern, and any arrangement pattern sufficient to guide the working fluid g (liquid) may be applicable. 
       FIG.  3    is a schematic diagram of a vapor chamber device according to another embodiment of the disclosure. With reference to  FIG.  3   , a main difference between a vapor chamber device  100   c  of  FIG.  3    and the vapor chamber device  100  of  FIG.  1 B  is that, in the present embodiment, a second capillary structure  130   c  has an opening  136  corresponding to a heat source  10 , and the entire opening  136  is filled with a third capillary structure  140 . In other words, in the present embodiment, the capillary structure that is in the evaporation area and that corresponds to the heat source  10  is mainly composed of the trenches  114  and the third capillary structure  140 . 
       FIG.  4    is a schematic diagram of a vapor chamber device according to another embodiment of the disclosure. With reference to  FIG.  4   , a main difference between a vapor chamber device  100 d of  FIG.  4    and the vapor chamber device  100  of  FIG.  1 B  is that, in the present embodiment, a first casing  110  has a cavity  116  corresponding to a heat source  10 , and a first capillary structure  113  is located outside the cavity  116 . The cavity  116  and the holes  134  (marked in  FIG.  1 C ) corresponding to the heat source  10  are filled with the third capillary structure  140 . In other words, in the present embodiment, the capillary structure that is in the evaporation area and that corresponds to the heat source  10  is mainly composed of the second capillary structure  130  and the third capillary structure  140 . 
       FIG.  5    is a schematic diagram of a vapor chamber device according to another embodiment of the disclosure. With reference to  FIG.  5   , a main difference between the vapor chamber device  100   e  of  FIG.  5    and the vapor chamber device  100   d  of  FIG.  4    is that, in the present embodiment, a second capillary structure  130   c  has an opening  136  corresponding to a heat source  10 , and the entire opening  136  is filled with a third capillary structure  140 . In other words, in the present embodiment, the capillary structure that is in the evaporation area and that corresponds to the heat source  10  is mainly composed of the third capillary structure  140 . 
     A contact surface of the first capillary structure and the second capillary structure may be sintered or bonded by thermocompression, and the third capillary structure between the first capillary structure and the second capillary structure may also be sintered to enhance the structural strength and heat-conducting performance. 
     Based on the above, for the vapor chamber device of the disclosure, in addition to the first capillary structure and the second capillary structure disposed between the first casing and the second casing to improve heat dissipation efficiency, the third capillary structure is further disposed in an area that is at the inner surface of the first plate and that corresponds to the heat source. With the third capillary structure, the liquid disposed in the vapor chamber device may be subject to greater capillary force and supplemented to the area more quickly, to improve the anti-drying capability of the area. Therefore, a sufficient amount of liquids may be maintained in the area for phase changes, and a probability that the vaporized liquid in the area cannot be supplemented to the area in time to cause excessive temperature rise of the heat source may be reduced. In this way, the vapor chamber device of the disclosure may exhibit better heat dissipation efficiency.