Heat diffusing device and method of producing the same

Abstract

A heat diffusing device includes first and second metallic thin plates that are alternately laminated to each other, and that are joined along with an upper sealing metallic thin plate and a lower sealing metallic thin plate by diffusion joining so as to form a sealed space in an interior defined by the first and second thin plates and the upper and lower sealing metallic thin plates. A C-shaped groove defined by a steep wall face is formed at a wall face defining the sealed space due to a difference (Δw) between the dimensions of the first metallic thin plates and the dimensions of the second metallic thin plates.

1 . A heat diffusing device comprising:
 first metallic thin plates and second metallic thin plates, dimensions of the first metallic thin plates being different from dimensions of the second metallic thin plates;   an upper sealing metallic thin plate; and   a lower sealing metallic thin plate,   wherein the first and second metallic thin plates are alternately laminated to each other, and are joined along with the upper and lower sealing metallic plates by diffusion joining so that a sealed space is formed in an interior defined by the first and second metallic thin plates and the upper and lower sealing metallic plates,   wherein a groove defined by a steep wall face is formed at a wall face defining the sealed space due to the difference between the dimensions of the first and second metallic thin plates, and   wherein a liquid is sealed in the groove under reduced pressure in an initial state.   
   
   
       2 . The heat diffusing device according to  claim 1 , wherein the sealed space is rectangular,
 wherein the groove communicates with an entire periphery of the sealed space, and   wherein one end portion side of the sealed space in a longitudinal direction is an evaporation portion, and the other end portion side of the sealed space in the longitudinal direction is a heat-exhausting portion.   
   
   
       3 . The heat diffusing device according to  claim 2 , wherein a plurality of the rectangular sealed spaces are disposed in parallel. 
   
   
       4 . The heat diffusing device according to  claim 1 , wherein the first and second metallic thin plates each have a plurality of radiating portions communicating with respective peripheral portions from respective central portions of the first and second metallic thin plates,
 wherein a radiating-portion pattern of each first metallic thin plate differs from a radiating-portion pattern of each second metallic thin plate,   wherein a flow path for a return liquid is disposed between the radiating portions of the metallic thin plates of one type that are laminated to each other so that the metallic thin plates of the one type are disposed on both sides of the metallic thin plates of the other type, and   wherein each central portion is the evaporation portion, and each peripheral portion is the heat-exhausting portion.   
   
   
       5 . The heat diffusing device according to  claim 1 , wherein the first and second metallic thin plates and the sealing metallic thin plates are formed of a same material. 
   
   
       6 . A method of producing a heat diffusing device comprising the steps of:
 alternately laminating first and second metallic thin plates to each other, and disposing sealing metallic thin plates at a top side and a bottom side of the laminated first and second metallic thin plates, dimensions of the first metallic thin plates being different from dimensions of the second metallic thin plates;   forming an integrated laminated body by subjecting the first and second metallic thin plates and the sealing metallic thin plates to diffusion bonding, forming a sealed space in an interior of the laminated body, and forming a groove at a wall face of the sealed space due to the difference between the dimensions of the first and second metallic thin plates, the groove being defined by a steep wall face; and   sealing a liquid in the groove in an initial state in which pressure in the sealed space is reduced.   
   
   
       7 . The method of producing the heat diffusing device according to  claim 6 , wherein thin plates each having a rectangular opening and a peripheral portion at the opening are used as the first and second metallic thin plates, the peripheral portions having different widths,
 wherein thin plates having areas allowing the openings to be closed are used as the upper and lower sealing metallic thin plates, and   wherein the groove communicating with an entire periphery of the sealed space, formed by the openings, is formed.   
   
   
       8 . The method of producing the heat diffusing device according to  claim 7 , wherein thin plates each having a plurality rectangular openings disposed in parallel are used as the first and second metallic thin plates. 
   
   
       9 . The method of producing the heat diffusing device according to  claim 6 , wherein thin plates each having a plurality of radiating portions communicating with a peripheral portion from a central portion, and each having an opening between the radiating portions, are used as the first and second metallic thin plates, patterns of the radiating portions of the thin plates differing from each other,
 wherein the sealed space is formed by the openings, and   wherein the groove is formed at the central portion and the peripheral portion of each thin plate.   
   
   
       10 . The heat diffusing device according to  claim 6 , wherein the first and second metallic thin plates and the sealing metallic thin plates are formed of thin plates of a same material.