Phase-change-type heat spreader, flow-path structure, electronic apparatus,and method of producing a phase-change-type heat spreader

Abstract

[Object] To provide a phase-change-type heat spreader, a flow-path structure, an electronic apparatus including the phase-change-type heat spreader, a flow-path structure used therein, and the like that are capable of improving a thermal efficiency by a phase change and lowering a thermal resistance. [Solving Means] Capillary boards ( 401 to 404 ) in which a plurality of openings ( 408 ) penetrating the capillary boards are formed on a wall surface constituting grooves ( 405 ) in a longitudinal direction of the grooves ( 405 ), are laminated while each being rotated 90 degrees to be deviated within an X-Y plane so that the grooves ( 405 ) of those layers extend in mutually-orthogonal directions, and the plurality of openings ( 408 ) function as a part of a vapor-phase flow path through which a vapor refrigerant evaporated by heat received by a heat-receiving plate circulates.

1 . A phase-change-type heat spreader to diffuse heat using a phase change of a working fluid, the phase-change-type heat spreader comprising:
 a container including a heat-receiving side and a heat-radiating side opposed to the heat-receiving side;   a plurality of flow paths provided in the container and laminated in a direction extending from the heat-receiving side to the heat-radiating side, each of the plurality of flow paths including a wall surface to cause the working fluid in a liquid phase to circulate by a capillary force; and   a vapor-phase flow path, including an opening, to cause the working fluid in a vapor phase evaporated by heat received on the heat-receiving side to circulate so that the working fluid in the vapor phase moves toward the heat-radiating side via the opening, the opening penetrating the wall surface so that the plurality of flow paths are brought in communication with one another.   
     
     
         2 . The phase-change-type heat spreader according to  claim 1 ,
 wherein the vapor-phase flow path includes a condensation area to condense the working fluid in the vapor phase, the condensation area being interposed between the heat-radiating side and the plurality of flow paths and being in communication with the plurality of flow paths via the opening.   
     
     
         3 . The phase-change-type heat spreader according to  claim 2 , further comprising
 a return flow path through which to return the working fluid in the liquid phase, that has been condensed in the condensation area, to the plurality of flow paths.   
     
     
         4 . The phase-change-type heat spreader according to  claim 2 ,
 wherein the condensation area includes:
 a first flow-path layer including a plurality of first condensation flow paths to cause the working fluid to circulate in a first direction, and 
 a second flow-path layer including a plurality of second condensation flow paths to cause the working fluid to circulate in a second direction different from the first direction and are in communication with the plurality of first condensation flow paths, the second flow-path layer being a layer different from the first flow-path layer in the direction extending from the heat-receiving side to the heat-radiating side. 
   
     
     
         5 . The phase-change-type heat spreader according to  claim 1 ,
 wherein the plurality of flow paths include
 a first flow-path layer including a plurality of first flow paths to cause the working fluid to circulate in a first direction, and 
 a second flow-path layer that includes a second flow path to cause the working fluid to circulate in a second direction different from the first direction and that is a layer different from the first flow-path layer in the direction extending from the heat-receiving side to the heat-radiating side. 
   
     
     
         6 . The phase-change-type heat spreader according to  claim 1 ,
 wherein the opening of the vapor-phase flow path is one of a plurality of openings and the plurality of openings are arranged in the direction in which the plurality of flow paths are laminated.   
     
     
         7 . The phase-change-type heat spreader according to  claim 1 ,
 wherein the container includes, on the heat-receiving side,
 an inlet for the working fluid, 
 an injection path that is in communication with at least one of the plurality of flow paths and the inlet, and 
 a press area to which to apply a pressure on the heat-receiving side and to block the injection path after the working fluid is injected into the plurality of flow paths via the inlet and the injection path, 
   wherein the phase-change-type heat spreader further comprises:
 a columnar portion erected in the direction in which the plurality of flow paths are laminated at a position corresponding to the press area. 
   
     
     
         8 . The phase-change-type heat spreader according to  claim 1 ,
 wherein the container includes, on the heat-radiating side,
 an inlet for the working fluid, 
 an injection path that is in communication with at least one of the plurality of flow paths and the inlet, and 
 a press area to which to apply a pressure on the heat-radiating side and to block the injection path after the working fluid is injected into the plurality of flow paths via the inlet and the injection path, 
   wherein the phase-change-type heat spreader further comprises
 a columnar portion erected in the direction in which the plurality of flow paths are laminated at a position corresponding to the press area. 
   
     
     
         9 . The phase-change-type heat spreader according to  claim 1 ,
 wherein a height of the plurality of flow paths in the direction in which the plurality of flow paths are laminated is 10 to 50 μm.   
     
     
         10 . The phase-change-type heat spreader according to  claim 1 , further comprising:
 a first structural member constituting the plurality of flow paths; and   a second structural member constituting the vapor-phase flow path,   wherein at least one of the container, the first structural member, and the second structural member is formed of copper.   
     
     
         11 . A phase-change-type heat spreader to diffuse heat using a phase change of a working fluid, the phase-change-type heat spreader comprising:
 a heat-receiving plate;   a heat-radiating plate opposed to the heat-receiving plate;   a plurality of first boards that each include a first groove to cause the working fluid in a liquid phase to circulate by a capillary force and an opening penetrating the first board so that the first grooves are brought in communication with one another so as to cause the working fluid in a vapor phase evaporated by heat received by the heat-receiving plate to circulate via the opening, the plurality of first boards being laminated in a direction extending from the heat-receiving plate to the heat-radiating plate; and   a second board that includes a second groove to cause the working fluid in the vapor phase that has passed through the opening to circulate and that is provided between the heat-radiating plate and the plurality of first boards.   
     
     
         12 . The phase-change-type heat spreader according to  claim 11 ,
 wherein the second groove penetrates the second board in the direction in which the plurality of first boards are laminated.   
     
     
         13 . The phase-change-type heat spreader according to  claim 11 ,
 wherein the second board includes a return hole to return the working fluid in the liquid phase that has passed through the second groove to be condensed to the plurality of flow paths.   
     
     
         14 . The phase-change-type heat spreader according to  claim 11 ,
 wherein the second board is one of a plurality of second boards, and at least one of the plurality of second boards includes a return hole to return the working fluid in the liquid phase that has passed through the second groove to be condensed to the plurality of flow paths.   
     
     
         15 . The phase-change-type heat spreader according to  claim 11 ,
 wherein a depth of the first grooves is 10 to 50 μm.   
     
     
         16 . The phase-change-type heat spreader according to  claim 11 ,
 wherein the plurality of first boards are each formed of copper.   
     
     
         17 . The phase-change-type heat spreader according to  claim 16 ,
 wherein at least one of the heat-receiving plate, the heat-radiating plate, and the second board is formed of copper.   
     
     
         18 . A flow-path structure used in a phase-change-type heat spreader to diffuse heat received by a heat-receiving plate using a phase change of a working fluid and that includes the heat-receiving plate, a heat-radiating plate opposed to the heat-receiving plate, and a board including a groove that causes the working fluid in a vapor phase evaporated by the heat received by the heat-receiving plate to circulate, the flow-path structure being laminated between the heat-receiving plate and the board, the flow-path structure comprising:
 a plurality of ribs extending within a plane between the heat-receiving plate and the heat-radiating plate; and   a wall surface, that includes an opening penetrating the flow-path structure, to cause the working fluid in the vapor phase to circulate so that the working fluid in the vapor phase moves toward the heat-radiating plate, and to cause the working fluid in a liquid phase to circulate by a capillary force, the wall surface being provided between the plurality of ribs.   
     
     
         19 . An electronic apparatus, comprising:
 a heat source; and   a phase-change-type heat spreader including
 a working fluid, 
 a container including a heat-receiving side to receive heat from the heat source and a heat-radiating side opposed to the heat-receiving side, 
 a plurality of flow paths provided in the container and laminated in a direction extending from the heat-receiving side to the heat-radiating side, each of the plurality of flow paths including a wall surface that causes the working fluid in a liquid phase to circulate by a capillary force, and 
 a vapor-phase flow path, including an opening, to cause the working fluid in a vapor phase evaporated by the heat received on the heat-receiving side to circulate so that the working fluid in the vapor phase moves toward the heat-radiating side via the opening, the opening penetrating the wall surface so that the plurality of flow paths are brought in communication with one another. 
   
     
     
         20 . A method of producing a phase-change-type heat spreader, the method comprising:
 laminating a heat-receiving plate, a plurality of boards each including a groove for causing a working fluid to circulate, and a heat-radiating plate such that the plurality of boards are interposed between the heat-receiving plate and the heat-radiating plate;   diffusion-bonding the heat-receiving plate, the plurality of boards, and the heat-radiating plate that have been laminated to form a flow path of the working fluid that corresponds to the grooves;   injecting the working fluid into the grooves via an injection path for the working fluid, the injection path being formed on the heat-receiving plate or the heat-radiating plate and in communication with the flow path; and   sealing, after the injection of the working fluid, an inside of the flow path by blocking the injection path before connecting a heat source to the heat-receiving plate by reflow.