Enhanced Wicks for Thermal Ground Planes

Abstract

A thermal ground plane is disclosed that includes one or more flattened or flattened and deformed mesh disposed within a cavity formed between a top casing and bottom casing. The flattened and deformed mesh, for example, may be created by compressing or flattening mesh such that the pores in the mesh are at least three times smaller than the pores in the mesh prior to flattening. The deformation can be formed to create a plurality of out of plane pillars in the mesh.

That which is claimed: 
     
         1 . A thermal ground plane comprising:
 a bottom casing;   a top casing, wherein an outer periphery of the bottom casing and an outer periphery of the top casing are bonded to each other to form a hermetic seal, wherein the bottom casing and the top casing form a cavity;   a working fluid disposed within the cavity; and   a flattened mesh disposed in the cavity on an inner surface of the bottom casing for liquid transport, wherein the flattened mesh comprises a plurality of openings that have a dimension that is at least three times smaller than the size of the openings prior to flattening.   
     
     
         2 . The thermal ground plane according to  claim 1 , wherein the flattened mesh comprises a woven mesh that has been flattened. 
     
     
         3 . The thermal ground plane according to  claim 1 , wherein an outer periphery of the flattened mesh is bonded between the outer periphery of the bottom casing and the outer periphery of the top casing form a hermetic seal. 
     
     
         4 . The thermal ground plane according to  claim 1 , wherein the flattened mesh comprises a plurality of woven wires that are bonded together. 
     
     
         5 . The thermal ground plane according to  claim 1 , further comprising a plurality of porous particles disposed within the plurality of openings of the flattened mesh. 
     
     
         6 . The thermal ground plane according to  claim 1 , wherein the flattened mesh comprises of a plurality of flattened mesh layers. 
     
     
         7 . The thermal ground plane according to  claim 1 , wherein the flattened mesh has been deformed to include a plurality of pillars for liquid transport that are formed in a pattern in the flattened mesh. 
     
     
         8 . The thermal ground plane according to  claim 1 , wherein the bottom casing comprises a plurality of pillars, and wherein the flattened mesh is bonded with a top of the plurality of pillars. 
     
     
         9 . The thermal ground plane according to  claim 1 , wherein at least a portion of the flattened mesh is surface treated with micro/nano-structures that improve heat transfer. 
     
     
         10 . The thermal ground plane according to  claim 1 , wherein at least a portion of the flattened mesh is surface coated with a low-temperature metal that improves diffusion bonding. 
     
     
         11 . The thermal ground plane according to  claim 1 , wherein at least a portion of the flattened mesh is surface coated with a copper layer with <1 1 1>crystal orientation for enhanced diffusion bonding. 
     
     
         12 . The thermal ground plane according to  claim 1 , wherein the flattened mesh comprises a solid copper sheet with a plurality of openings where the plurality of openings were etched, laser drilled, electroplated, or electroless plated into the solid copper sheet. 
     
     
         13 . The thermal ground plane according to  claim 1 , wherein a bond between the bottom casing and the top casing comprises a single, continuous bond. 
     
     
         14 . The thermal ground plane according to  claim 1 , wherein the flattened mesh comprises a plurality of wires comprising copper, stainless steel, glass, or metal-coated polymer. 
     
     
         15 . The thermal ground plane according to  claim 1 , wherein the flattened mesh is fabricated by hot works, cold works, thermocompression, thermosonic, ultrasonic, laser welding, sintering, diffusion bonding, or electrical welding. 
     
     
         16 . The thermal ground plane according to  claim 1 , wherein the flattened mesh comprises a lower flattened mesh layer, an upper flattened mesh layer, and a middle mesh layer that is not flattened and is sandwiched between the upper mesh layer and the lower mesh layer, wherein the upper mesh layer is a flattened mesh to prevent vapor penetration into the middle mesh. 
     
     
         17 . The thermal ground plane according to  claim 16 , wherein the flattened mesh comprises an artery liquid channel. 
     
     
         18 . The thermal ground plane according to  claim 16 , wherein the flattened mesh comprises a plurality of mesh layers including multiple liquid transport layers. 
     
     
         19 . The thermal ground plane according to  claim 16 , wherein the lower mesh is coupled with a fourth mesh for liquid transport, wherein the fourth mesh includes a plurality of openings and the lower mesh includes a plurality of openings having a substantially similar dimension. 
     
     
         20 . A thermal ground plane comprising:
 a bottom casing;   a top casing, wherein an outer periphery of the bottom casing and an outer periphery of the top casing are bonded to each other to form a hermetic seal, wherein the bottom casing and the top casing form a cavity;   a working fluid disposed within the cavity;   a flattened mesh comprising a lower flattened mesh layer, an upper flattened mesh layer, and a middle mesh layer sandwiched between the upper mesh layer and the lower mesh layer, wherein the flattened mesh is disposed in the cavity on an inner surface of the bottom casing, wherein each of the lower flattened mesh layer and an upper flattened mesh layer comprises a plurality of openings that have a dimension that is at least three times smaller than the size of the openings prior to flattening.   
     
     
         21 . The thermal ground plane according to  claim 20 , wherein an outer periphery of the flattened mesh is bonded between the outer periphery of the bottom casing and the outer periphery of the top casing form a hermetic seal. 
     
     
         22 . A thermal ground plane comprising:
 a bottom casing;   a top casing, wherein an outer periphery of the bottom casing and an outer periphery of the top casing are bonded to each other to form a hermetic seal, wherein the bottom casing and the top casing form a cavity;   a working fluid disposed within the cavity;   a flattened mesh disposed in the cavity on an inner surface of the bottom casing, the flattened mesh comprises a plurality of openings that have a dimension of about 1-20 um and the flattened mesh has a thickness of about 5-20 um.   
     
     
         23 . The thermal ground plane according to  claim 22 , wherein the flattened mesh comprises a woven mesh that has been pressed to form the flattened mesh, wherein the woven mesh has a plurality of pores that have a dimension more than three times larger than a dimension of the plurality of openings. 
     
     
         24 . The thermal ground plane according to  claim 22 , wherein an outer periphery of the flattened mesh is bonded between the outer periphery of the bottom casing and the outer periphery of the top casing form a hermetic seal. 
     
     
         25 . The thermal ground plane according to  claim 22 , wherein the flattened mesh comprises a plurality of longitudinal wires and a plurality of latitudinal wires that are bonded together where the plurality of longitudinal wires and a plurality of latitudinal wires cross each other.