Patent Publication Number: US-2021195799-A1

Title: Vapor chamber

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This non-provisional application claims priority under 35 U.S.C. § 119(a) on Patent Application No(s). 201911340537.1 filed in China, P.R.C. on Dec. 23, 2019, the entire contents of which are hereby incorporated by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a vapor chamber, more particularly to a vapor chamber having multiple forms of capillary structures. 
     BACKGROUND 
     A vapor chamber and a heat pipe can be applied to dissipate heat. Thermal conduction of a heat pipe occurs in one dimension while thermal conduction of a vapor chamber occurs in two dimensions. Therefore, the vapor chamber is more effective in heat dissipation. Generally, the vapor chamber includes a chamber body and a capillary structure, the chamber body has a chamber for accommodating cooling fluid, and the capillary structure is distributed in the chamber. The chamber body contains an evaporation area and a condensation area. The cooling fluid absorbs heat and is vaporized in the evaporation area. And the vaporized cooling fluid is condensed in the condensation area and then returned to the evaporation area via the capillary structure to form a circulation. 
     However, with the increasing demand for lightweight and small electronic products, some vapor chambers are in an irregular shape to avoid structural interference with nearby electrical components. This shape of vapor chamber inevitably has a narrow portion, where the narrow portion has a small cross-section for the distribution of the capillary structure so that the cooling fluid is often stuck in this area and unable to complete the circulation, especially when the vapor chamber is placed vertically. 
     SUMMARY 
     The present disclosure provides a vapor chamber that has an improved ability to circulate cooling fluid. 
     According to one aspect of the present disclosure, a vapor chamber is configured to accommodate a cooling fluid. The vapor chamber includes a first cover, a second cover, a first capillary structure, and a second capillary structure. The second cover and the first cover are attached to each other to form a chamber therebetween. The chamber is configured to accommodate the cooling fluid. The first capillary structure is located in the chamber and stacked on the first cover. The second capillary structure is located in the chamber and stacked on the first capillary structure. The second capillary structure is different from the first capillary structure, and a projection of the second capillary structure onto the first cover is smaller than a projection of the first capillary structure onto the first cover. 
     According to another aspect of the present disclosure, a vapor chamber is configured to accommodate a cooling fluid. The vapor chamber includes a first cover, a second cover, a first capillary structure, and a second capillary structure. The second cover and the first cover are attached to each other to form a chamber therebetween. The chamber is configured to accommodate the cooling fluid. The first capillary structure is located in the chamber and stacked on the first cover. The second capillary structure is located in the chamber and stacked on the first capillary structure. The second capillary structure has a capability of transmitting the cooling fluid stronger than that of the first capillary structure. 
     According to the vapor chamber discussed above, when the vapor chamber is placed vertically and the evaporation area is located higher than the condensation area, or when the evaporation area and the condensation area have a relative long distance inbetween, the condensed cooling fluid in the condensation area still can be transmitted back to the evaporation area with the help of the second capillary structure and the first capillary structure to complete the circulation. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present disclosure will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only and thus are not intending to limit the present disclosure and wherein: 
         FIG. 1  is a perspective view of a vapor chamber according to a first embodiment of the present disclosure; 
         FIG. 2  is another perspective view of the vapor chamber in  FIG. 1 ; 
         FIG. 3  is a plan view showing that the vapor chamber in  FIG. 1  without the second cover; 
         FIG. 4  is a cross-sectional view of the vapor chamber in  FIG. 1 ; 
         FIG. 5  is a cross-sectional view of a vapor chamber according to a second embodiment of the present disclosure; 
         FIG. 6  is a plan view showing that a vapor chamber without a second cover according to a third embodiment of the present disclosure; 
         FIG. 7  is a plan view showing that a vapor chamber without a second cover according to a fourth embodiment of the present disclosure; 
         FIG. 8  is a plan view showing that a vapor chamber without a second cover according to a fifth embodiment of the present disclosure; 
         FIG. 9  is a plan view showing that a vapor chamber without a second cover according to a sixth embodiment of the present disclosure; 
         FIG. 10  is a plan view showing that a vapor chamber without a second cover according to a seventh embodiment of the present disclosure; 
         FIG. 11  is a plan view showing that a vapor chamber without a second cover according to an eighth embodiment of the present disclosure; 
         FIG. 12  is a plan view showing that a vapor chamber without a second cover according to a ninth embodiment of the present disclosure; 
         FIG. 13  is a plan view showing that a vapor chamber without a second cover according to a tenth embodiment of the present disclosure; 
         FIG. 14  is a plan view showing that a vapor chamber without a second cover according to an eleventh embodiment of the present disclosure; and 
         FIG. 15  is a plan view showing that a vapor chamber without a second cover according to a twelfth embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In the following detailed description, for purposes of explanation, numerous specific details are set forth in order to provide a thorough understanding of the disclosed embodiments. It will be apparent, however, that one or more embodiments may be practiced without these specific details. In other instances, well-known structures and devices are schematically shown in order to simplify the drawing. 
     Please refer to  FIG. 1  to  FIG. 4 , wherein  FIG. 1  is a perspective view of a vapor chamber according to a first embodiment of the present disclosure,  FIG. 2  is another perspective view of the vapor chamber in  FIG. 1 ,  FIG. 3  is a plan view showing that the vapor chamber in  FIG. 1  without the second cover, and  FIG. 4  is a cross-sectional view of the vapor chamber in  FIG. 1 . 
     This embodiment provides a vapor chamber  10  configured to accommodate a cooling fluid (not shown). The vapor chamber  10  includes a first cover  100 , a second cover  200 , a first capillary structure  300 , and a second capillary structure  400 . 
     The first cover  100  and the second cover  200  are made of, for example, oxygen-free copper, silicon-containing copper alloy, or phosphorous copper alloy. The second cover  200  and the first cover  100  are attached to each other to form a chamber S therebetween. The cooling fluid is accommodated in the chamber S. 
     In this embodiment, the vapor chamber  10  may further include a plurality of supporting posts  270 . The supporting posts  270  are in physical contact with the first cover  100  and the second cover  200 . The supporting posts  270  are able to maintain the gap between the first cover  100  and the second cover  200  and to strengthen the structural strength of the vapor chamber  10 . 
     In this embodiment, the vapor chamber  10  further includes a hollow part  500 . The hollow part  500  is, for example, a through hole formed on the first cover  100  and the second cover  200 , but the hollow part  500  does not affect the airtightness of the chamber S. Specifically, there are an outer seal part  250  and an inner seal part  260  provided along the contours of the first cover  100  and the second cover  200 , where the outer seal part  250  goes along the outer edges of the first cover  100  and the second cover  200 , and the inner seal part  260  goes along the contour of the hollow part  500 . Note that the contours of the outer seal part  250  and the inner seal part  260  may be in irregular shapes to avoid structural interference with nearby electrical components (not shown), but the present disclosure is not limited thereto. In some embodiments, the outer seal part and the inner seal part in irregular shapes may have a zigzag structure, a curved structure or an uneven structure. In some other embodiments, the contours of the outer seal part and the inner seal part may be in a regular shape, such as rectangle, oval, or circle. 
     In this embodiment, the chamber S has an evaporation area A 1  and a condensation area A 2 . As shown, due to the existence of the hollow part  500  and the irregular shape, the condensation area A 2  is narrower than the evaporation area A 1  (W 2  is smaller than W 1 ). 
     In this embodiment, the first cover  100  has a contact surface  110  corresponding to the evaporation area A 1 . The contact surface  110  is configured to be in thermal contact with a heat source (not shown). 
     The first capillary structure  300  and the second capillary structure  400  are located in the chamber S. The first capillary structure  300  is stacked on the first cover  100 , and the second capillary structure  400  is stacked on the first capillary structure  300 . The second capillary structure  400  is different from the first capillary structure  300 . An orthogonal projection of the second capillary structure  400  onto the first cover  100  is smaller than that of the first capillary structure  300  onto the first cover  100 . The orthogonal projection is also known as the orthographic projection. Note that the orthogonal projections are projected along the same direction perpendicular to the surface of the first cover  100 . Note that the orthogonal projection is for the purpose of description and is not intended to limit the present disclosure. In some embodiments, the relationship between the first capillary structure  300  and the second capillary structure  400  can be described using their oblique projections, where the oblique projections are projected along the same direction which is at an acute or obtuse angle to the surface of the first cover  100 . 
     In this embodiment, the first capillary structure  300  is made of, for example, a metal mesh, and the second capillary structure  400  is made from, for example, sintered powder, however, the present disclosure is not limited thereto. The first capillary structure  300  and the second capillary structure  400  may be made of different materials. In one embodiment, the first capillary structure  300  is made of gold, and the second capillary structure  400  is made of copper. In another embodiment, the first capillary structure  300  and the second capillary structure  400  are made of different alloys. In addition, the first capillary structure  300  and the second capillary structure  400  may be different in the form of capillary. In one embodiment, the first capillary structure  300  may be in one form of having groove structure, mesh structure, fiber structure, or sintered powder structure, and the second capillary structure  400  may be in another form of having groove structure, mesh structure, fiber structure, or sintered powder structure. The first capillary structure  300  and the second capillary structure  400  may be in the same type but have different pore sizes; in one embodiment, the first capillary structure  300  and the second capillary structure  400  are in the form having mesh structure, but the pores of the first capillary structure  300  are larger than that of the second capillary structure  400 . 
     In this embodiment, as shown, the first capillary structure  300  is distributed throughout the chamber S, and the second capillary structure  400  is distributed in part of the chamber S. One side of the second capillary structure  400  is located in the condensation area A 2  and another side of the second capillary structure  400  extends towards the evaporation area A 1 . However, the distributions of the first capillary structure  300  and the second capillary structure  400  in the chamber S are not restricted; in some embodiments, the first capillary structure may also be merely distributed in part of the chamber S as long as the orthogonal projection of the second capillary structure onto the first cover is smaller than that of the first capillary structure onto the first cover. 
     In this embodiment, the orthogonal projection of the second capillary structure  400  onto the first cover  100  does not overlap with the contact surface  110 , where the range of the contact surface  110  on the first cover  100  is illustrated as the area C. Specifically, the second capillary structure  400  is in a ring-shape and has a first curved section  410 , a second curved section  420 , and two extension sections  430 . The first curved section  410  and the second curved section  420  are located opposite to each other. The first curved section  410  is located in the condensation area A 2 , and at least part of the second curved section  420  is located in the evaporation area A 1 . An orthogonal projection of the second curved section  420  onto the first cover  100  is located out of and substantially located next to the area C of the contact surface  110  of the first cover  100 . The extension sections  430  are located opposite to each other. The extension sections  430  are respectively located between and connected to the first curved section  410  and the second curved section  420 . In such an arrangement, the cooling fluid in the condensation area A 2  will be transmitted to a place near the contact surface  110  in the evaporation area A 1  via the second capillary structure  400  and then be transmitted to the contact surface  110  in the evaporation area A 1  via the first capillary structure  300 . 
     In this embodiment, the second capillary structure  400  is in a ring-shape and located at the periphery of the hollow part  500 . In other words, the second capillary structure  400  surrounds the hollow part  500 . In addition, the second capillary structure  400  is located close to an attachment surface  260 ′ of the inner seal part  260  but is located away from an attachment surface  250 ′ of the outer seal part  250 . As shown, the distance between the second capillary structure  400  and the attachment surface  260 ′ is smaller than the distance between the second capillary structure  400  and the attachment surface  250 ′. Such an arrangement of the second capillary structure  400  in the chamber S makes the chamber S has a large available room for the vaporized cooling fluid to flow, ensuring the flowing of the cooling fluid in the chamber S. 
     In addition, as shown in  FIG. 4 , in this embodiment, the second capillary structure  400  is spaced apart from the second cover  200 . That is, the second capillary structure  400  is not in directly thermally conductive contact with the second cover  200 . 
     When the vapor chamber  10  is placed vertically and the evaporation area A 1  is located higher than the condensation area A 2 , or when the evaporation area A 1  and the condensation area A 2  have a relative long distance inbetween, the condensed cooling fluid in the condensation area A 2  still can be transmitted back to the evaporation area A 1  with the help of the second capillary structure  400  and the first capillary structure  300  to complete the circulation 
     In this embodiment, the vapor chamber  10  may be manufactured by the following steps: firstly, the first capillary structure  300  is sintered on the first cover  100 ; then, the second capillary structure  400  being pre-sintered is stacked on the first capillary structure  300 ; then, the first cover  100  and the second cover  200  are soldered to each other. Note that the second capillary structure  400  is not necessary to be pre-sintered; in some embodiments, the second capillary structure may be produced by placing capillary material on the first capillary structure and sintering it. 
     In the above embodiment, the second capillary structure  400  is spaced apart from the second cover  200 , but the present disclosure is not limited thereto. Please refer to  FIG. 5 , which is a cross-sectional view of a vapor chamber according to a second embodiment of the present disclosure. Note that only the main differences between the following embodiments and the previous embodiment will be described hereinafter. And the same numbers refer to the same or similar features. In this embodiment, the second capillary structure  400   a  is in thermal contact with the second cover  200  so as to enhance the heat exchange efficiency. 
     In the above embodiments, the second capillary structure  400  is located close to the attachment surface  260 ′ of the inner seal part  260 . However, the present disclosure is not limited thereto. Please refer to  FIG. 6 , which is a plan view showing that a vapor chamber without a second cover according to a third embodiment of the present disclosure. In this embodiment, the second capillary structure  400   b  is located close to the attachment surface  250 ′ of the outer seal part  250  (shown in  FIG. 1 ). Such an arrangement of the second capillary structure  400   b  in the chamber S makes the chamber S has a large available room for the vaporized cooling fluid to flow, ensuring the flowing of the cooling fluid in the chamber S. 
     In the above embodiments, the orthogonal projection of the second capillary structure  400  onto the first cover  100  is located out of the area C of the contact surface  110  of the first cover  100 . However, the present disclosure is not limited thereto. Please refer to  FIG. 7 , which is a plan view showing that a vapor chamber without a second cover according to a fourth embodiment of the present disclosure. In this embedment, part of the orthogonal projection of the second capillary structure  400   c  onto the first cover  100  is located in the area C of the contact surface  110  of the first cover  100 . Specifically, the second capillary structure  400   c  is in a ring-shape and has a first curved section  410   c,  a second curved section  420   c,  two extension sections  430   c,  and a bridge section  440   c.  The first curved section  410   c  and the second curved section  420   c  are located opposite to each other. The first curved section  410   c  is located in the condensation area A 2 , and at least part of the second curved section  420   c  is located in the evaporation area A 1 . An orthogonal projection of the second curved section  420   c  onto the first cover  100  is located out of the area C of the contact surface  110  of the first cover  100 . The extension sections  430   c  are located opposite to each other. The extension sections  430   c  are respectively located between and connected to the first curved section  410   c  and the second curved section  420   c . One end of the bridge section  440   c  is connected to the second curved section  420   c,  and an orthogonal projection of another end of the bridge section  440   c  onto the first cover  100  is located in the area C of the contact surface  110  of the first cover  100 . In such an arrangement, the cooling fluid in the condensation area A 2  will be transmitted to the contact surface  110  in the evaporation area A 1  via the second capillary structure  400   c.    
     In the above embodiments, the second capillary structure is in a ring-shape. However, the present disclosure is not limited thereto. Please refer to  FIG. 8  and  FIG. 9 , wherein  FIG. 8  is a plan view showing that a vapor chamber without a second cover according to a fifth embodiment of the present disclosure, and  FIG. 9  is a plan view showing that a vapor chamber without a second cover according to a sixth embodiment of the present disclosure. As shown in  FIG. 8 , in this embodiment, the second capillary structure  400   d  is in a U-shape and has a curved section  460   d  and two extension sections  470   d.  The curved section  460   d  is located in the condensation area A 2 . The extension sections  470   d  are located opposite to each other. The extension sections  470   d  are respectively connected to two opposite ends of the curved section  460   d  and extend towards the evaporation area A 1 . An orthogonal projection of an end of each of the extension sections  470   d  located away from the curved section  460   d  onto the first cover  100  is located in the area C of the contact surface  110  of the first cover  100 . As shown in  FIG. 9 , the second capillary structure  400   e  is in a U-shape and has a curved section  460   e  and two extension sections  470   e.  The curved section  460   e  is located in the condensation area A 2 . The extension sections  470   e  are located opposite to each other. The extension sections  470   e  are respectively connected to two opposite ends of the curved section  460   e  and extend towards the evaporation area A 1 . An orthogonal projection of an end of each of the extension sections  470   e  located away from the curved section  460   e  onto the first cover  100  is located out of and substantially located next to the area C of the contact surface  110  of the first cover  100 . 
     In the above embodiments, the vapor chamber  10  has a hollow part  500  (shown in  FIG. 1 ). However, the present disclosure is not limited thereto. Please refer to  FIG. 10 , which is a plan view showing that a vapor chamber without a second cover according to a seventh embodiment of the present disclosure. In this embodiment, the orthogonal projection of the second capillary structure  400   f  onto the first cover  100   f  is located out of and substantially located next to the area C of the contact surface  110  of the first cover  100   f . Specifically, the second capillary structure  400   f  is in a ring-shape and has a first curved section  410   f,  a second curved section  420   f,  and two extension sections  430   f.  The first curved section  410   f  and the second curved section  420   f  are located opposite to each other. The first curved section  410   f  is located in the condensation area A 2 , and the second curved section  420   f  is located next to the evaporation area A 1 . An orthogonal projection of the second curved section  420   f  onto the first cover  100   f  is located out of and substantially located next to the area C of the contact surface  110  of the first cover  100   f.  The extension sections  430   f  are located opposite to each other. The extension sections  430   f  are respectively located between and connected to the first curved section  410   f  and the second curved section  420   f.  In such an arrangement, the cooling fluid in the condensation area A 2  will be transmitted to a place near the contact surface  110  in the evaporation area A 1  via the second capillary structure  400   f  and then be transmitted to the contact surface  110  in the evaporation area A 1  via the first capillary structure  300 . 
     Please refer to  FIG. 11 , which is a plan view showing that a vapor chamber without a second cover according to an eighth embodiment of the present disclosure. 
     In this embodiment, the second capillary structure  400   g  is located close to the attachment surface  250 ′ of the outer seal part  250  (shown in  FIG. 1 ). Such an arrangement of the second capillary structure  400   g  in the chamber S makes the chamber S has a large available room for the vaporized cooling fluid to flow, ensuring the flowing of the cooling fluid in the chamber S. 
     Please refer to  FIG. 12 , which is a plan view showing that a vapor chamber without a second cover according to a ninth embodiment of the present disclosure. 
     In this embodiment, part of the orthogonal projection of the second capillary structure  400   h  onto the first cover  100   h  is located in the area C of the contact surface  110  of the first cover  100   h.  Specifically, the second capillary structure  400   h  is in a ring-shape and has a first curved section  410   h,  a second curved section  420   h,  two extension sections  430   h,  and a bridge section  440   h.  The first curved section  410   h  and the second curved section  420   h  are located opposite to each other. The first curved section  410   h  is located in the condensation area A 2 , and the second curved section  420   h  is located next to the evaporation area A 1 . An orthogonal projection of the second curved section  420   h  onto the first cover  100   h  is located out of the area C of the contact surface  110  of the first cover  100   h.  The extension sections  430   h  are located opposite to each other. The extension sections  430   h  are respectively located between and connected to the first curved section  410   h  and the second curved section  420   h.  One end of the bridge section  440   h  is connected to the second curved section  420   h,  and an orthogonal projection of another end of the bridge section  440   h  onto the first cover  100   h  is located in the area C of the contact surface  110  of the first cover  100   h.  In such an arrangement, the cooling fluid in the condensation area A 2  will be transmitted to the contact surface  110  in the evaporation area A 1  via the second capillary structure  400   h.    
     Please refer to  FIG. 13  and  FIG. 14 , wherein  FIG. 13  is a plan view showing that a vapor chamber without a second cover according to a tenth embodiment of the present disclosure, and  FIG. 14  is a plan view showing that a vapor chamber without a second cover according to an eleventh embodiment of the present disclosure. 
     As shown in  FIG. 13 , in this embodiment, the second capillary structure  400   i  is in a U-shape and has a curved section  460   i  and two extension sections  470   i.  The curved section  460   i  is located in the condensation area A 2 . The extension sections  470   i  are located opposite to each other. The extension sections  470   i  are respectively connected to two opposite ends of the curved section  460   i  and extend towards the evaporation area A 1 . An orthogonal projection of an end of each of the extension sections  470   i  located away from the curved section  460   i  onto the first cover  100   i  is located in the area C of the contact surface  110  of the first cover  100   i.  As shown in  FIG. 14 , the second capillary structure  400   j  is in a U-shape and has a curved section  460   j  and two extension sections  470   j.  The curved section  460   j  is located in the condensation area A 2 . The extension sections  470   j  are located opposite to each other. The extension sections  470   j  are respectively connected to two opposite ends of the curved section  460   j  and extend towards the evaporation area A 1 . An orthogonal projection of an end of each of the extension sections  470   j  located away from the curved section  460   j  onto the first cover  100   j  is located out of and substantially located next to the area C of the contact surface  110  of the first cover  100   j.    
     In the above embodiments, the extension sections are spaced apart from each other. However, the present disclosure is not limited thereto. Please refer to  FIG. 15 , which is a plan view showing that a vapor chamber without a second cover according to a twelfth embodiment of the present disclosure. In this embodiment, the extension sections  470   k  abut to each other. 
     Note that the distribution area of the second capillary structure  400  may greater than or equal to the distribution area of the first capillary structure  300  with the premise that the second capillary structure  400  has a capability of transmitting the cooling fluid stronger than that of the first capillary structure  300 . That is, the present disclosure is not limited to that the orthogonal projection of the second capillary structure  400  onto the first cover  100  is smaller than that of the first capillary structure  300  onto the first cover  100  with the premise stated above. Herein, the capability of transmitting the cooling fluid is proportional to the degree of capillary action. 
     In addition, in the above embodiments, the first capillary structure  300  is stacked on the first cover  100 . However, the present disclosure is not limited thereto. In some embodiments, the first capillary structure may be stacked on the second cover. 
     According to the vapor chamber discussed above, when the vapor chamber is placed vertically and the evaporation area is located higher than the condensation area, or when the evaporation area and the condensation area have a relative long distance inbetween, the condensed cooling fluid in the condensation area still can be transmitted back to the evaporation area with the help of the second capillary structure and the first capillary structure to complete the circulation. 
     The embodiments are chosen and described in order to best explain the principles of the present disclosure and its practical applications, to thereby enable others skilled in the art best utilize the present disclosure and various embodiments with various modifications as are suited to the particular use being contemplated. It is intended that the scope of the present disclosure is defined by the following claims and their equivalents.