초록 ▼

New heat spreaders are proposed to connect high power, high heat generating electronic devices to their downstream heat dissipating cooling components. First, the spreaders distribute the high heat flux over a wider surface area, thus reducing the flux to levels more easily handled by the downstream

New heat spreaders are proposed to connect high power, high heat generating electronic devices to their downstream heat dissipating cooling components. First, the spreaders distribute the high heat flux over a wider surface area, thus reducing the flux to levels more easily handled by the downstream cooling system. Second, the spreaders incorporate flexible columns or elements to join the electronic devices to the main body of the spreader, so as to negate the undesirable effects of CTE mismatch. Columns with a higher standoff distance between the components are more flexible than a direct flat interface attachment between the heat source and the heat sink, and will have less chance of delaminating. Several embodiments are proposed and can be used in appropriate situations. The heat spreaders can be helpful in harsh environments and in high heat generating applications, such as spacecraft, satellites, as well as land locked high power computer systems.

대표청구항 ▼

1. A multi-level heat spreader, for transferring heat from a primary heat source, generating a certain amount of heat, exiting from a primary heat source heat exit area, with a certain heat source heat flux, to a final heat dissipating device, wherein a) said heat source heat flux is larger that the

1. A multi-level heat spreader, for transferring heat from a primary heat source, generating a certain amount of heat, exiting from a primary heat source heat exit area, with a certain heat source heat flux, to a final heat dissipating device, wherein a) said heat source heat flux is larger that the heat flux that can be tolerated by said final heat dissipating device,b) said multi-level heat spreader comprising:c) a first level heat spreader unit and second level heat spreader unit, whereind) said first level heat spreader unit comprises a number of first heat conducting elongated elements and a first heat conducting platform;e) said second level heat spreader unit comprising a number of second heat conducting elongated elements and a second heat conducting platform;f) each one of said first heat conducting elongated elements having a foot, attached to and thermally engaging said primary heat source at the primary heat source heat exit area, and a head, at the opposite end of the elongated element, attached to and thermally engaging said first heat conducting platform;g) each one of said second heat conducting elongated elements having a foot attached to and thermally engaging said first heat conducting platform, and a head, at the opposite end of the elongated element, attached to and thermally engaging said second heat conducting platform; whereinh) the heat is transmitted from the primary heat source heat exit area through the first heat conducting elongated elements of the first level heat spreader unit to the first heat conducting platform, and subsequently the heat is transferred from said first heat conducting platform through the second heat conducting elongated elements of said second level heat spreader unit to the second level heat conducting platform, thusi) said first heat conducting platform is acting as the heat source for the second level heat spreader unit, and whereinj) a heat exit surface area of said first heat conducting platform is larger than the surface area of the primary heat source heat exit area, resulting in that the heat flux at the surface of the first heat conducting platform is smaller than the heat flux at the primary heat source heat exit area, and whereink) a heat exit surface area of said second heat conducting platform is larger yet than the surface area of the first heat conducting platform, resulting in that the heat flux at the surface of the second heat conduction platform is smaller yet than the heat flux at the surface area of the first heat conducting platform, thusl) said multi-level heat spreader providing a greater reduction of the heat flux at the surface area of the second heat conducting platform compared to the heat flux at the primary heat source heat exit area, whereinm) said heat flux at the surface area of the second heat conducting platform is considerably smaller than the heat flux at the primary heat source heat exit area, and is better adapted to engage said final heat dissipating device, compared to the heat flux at the primary heat source heat exit area. 2. A multi-level heat spreader, as in claim 1, wherein the elongated elements of at least one of the first and second heat spreader units are parallel to each other. 3. A multi-level heat spreader, as in claim 1, wherein the elongated elements of at least one of the first and second heat spreader units are shaped to be spreading out, fanning out, from the small area of the heat source, to the larger area of the platform, whereinthe elongated element at the center is perpendicular to the heat source, and the outwardly elongated elements are inclined on a certain angle with respect to the heat source, whereinthe angle gets larger as the elongated elements get further away from the center. 4. A multi-level heat spreader, as in claim 1, wherein each one of the heat conducting elongated elements, of at least one of the first and second heat spreader units has various cross sectional areas along the length of the elongated elements, wherein the cross sectional area of the elongated elements is smaller near the foot of the elongated elements than the cross sectional area of the elongated elements near the head of the elongated elements. 5. A multi-level heat spreader, as in claim 1, wherein gaps between the elongated elements of at least one of the first and second heat spreader units are uniform in size, wherein the elongated elements have a narrow cross-section near the foot of elongated elements, near the heat source and have a larger cross-section near the head of the elongated elements, near the platform. 6. A multi-level heat spreader, as in claim 1, wherein the elongated elements of at least one of the first and second heat spreader units are curvilinear. 7. A multi-level heat spreader, as in claim 1, wherein the elongated elements of at least one of the first and second heat spreader units are parallel nested. 8. A multi-level heat spreader, as in claim 1, wherein the elongated elements of at least one of the first and second heat spreader units are shaped so that the foot of every elongated element is shaped to have a tip of the foot perpendicular to the surface that said tip is attached to, and the head of every elongated element is shaped to have a tip of the head perpendicular to the surface that said tip is attached to. 9. A multi-level heat spreader, as in claim 1, wherein the elongated elements of at least one of the first and second heat spreader units are shaped so that a tip of the foot of every elongated element is beveled, so that the surface of said beveled tip is along a plane, parallel to the surface of the heat source exit surface area, where said respective foot will be attached to. 10. A multi-level heat spreader, as in claim 1, wherein at least of the first and second elongated elements are made of flexible curvilinear wires, strings, or fibers, including heat conductive carbon fibers, or nano fibers. 11. A multi-level heat spreader, as in claim 1, wherein the platform of at least one of the first and second heat spreader units is thicker near its center and gets thinner as it gets closer to outside edges of the platform. 12. A multi-level heat spreader, as in claim 1, wherein each of the individual elements of the first and second heat spreader units is made of its respective individual material, having its respective physical properties and individual coefficient of thermal expansion (CTE) and its individual shapes and dimensions and wherein the first and second elongated elements are flexible enough to absorb and to accommodate any changes and differences in shapes and dimensions between the individual elements, due to changes in their temperatures and due to their respective original shapes and dimensions and coefficient of thermal expansion. 13. A multi-level heat spreader, as in claim 1, wherein the elongated elements of at least one of the first and second heat spreader units, and the platform to which these elongated elements are attached, are all created out of one single piece of material. 14. A multi-level heat spreader, as in claim 1, wherein the first and second heat conducting platforms of the heat spreader units have a rim, including an elevated ledge along the edges of the platform top surface, to help in containing any molten joining material used to join the elongated elements, when the first and second elongated elements get attached to their respective first and second heat conducting platforms, wherein the joining material is in a liquid state at any time during the joining process. 15. A multi-level heat spreader, as in claim 1, wherein the multi-level heat spreader comprises more than two levels of heat spreaders. 16. A multi-level heat spreader, as in claim 1, wherein the platform of at least one of the first and second heat spreader units comprises at least one extension, wherein at least one more heat spreader unit is attached to said extension. 17. A multi-level heat spreader, as in claim 16, wherein said extension is a flexible heat pipe. 18. A multi-level heat spreader, as in claim 16, wherein at least one of the first and second heat conducting platforms is supported by support means, which are anchored on to rigid bases, wherein said support means are designed to accommodate and to allow for free movements of the individual heat spreader elements. 19. A multi-level heat spreader, as in claim 1, wherein the elongated elements of at least one of the first and second heat spreader units are distributed along the surface of their respective heat conducting platforms in a distribution pattern, in one of the following group of patterns, comprising a rectangular pattern, a circular pattern, an hexagonal pattern, a triangular pattern, a radial pattern, and a linear pattern. 20. A multi-level heat spreader, as in claim 1, wherein tips of the feet of the elongated elements of at least one of the first and second heat spreader units are having a smaller cross-section than the cross-section along a length of the elongated elements, to facilitate the attachment of the elongated elements to their respective heat source and wherein the heat exit surface of the respective heat source is shaped to have individual recesses, forming individual pockets, each one of said pockets being shaped to receive one respective elongated element mounted on top of said recess. 21. A multi-level heat spreader, as in claim 20, wherein the pockets comprise anchor elements, wherein each one of said anchor elements is made of a material, which can be easily attached to both the elongated elements and to the pockets, and whereinsaid anchor elements act as isolated islands and are not touching any of the neighboring anchor elements, so that said island will not be affected by temperature variations and by their coefficient of thermal expansion (CTE), and wherein said islands can be located in a distribution pattern from the group comprising a rectangular pattern, a circular pattern, an hexagonal pattern, a triangular pattern, and a radial pattern, a linear pattern, and wherein said islands pattern matches the distribution pattern of the respective elongated elements which will be attached to said islands. 22. A multi-level heat spreader, as in claim 1, wherein one of the first and second heat conducting platforms is constructed to comprise at least one cooling device, wherein said cooling device utilizes the heat pipe cooling methods and principles, and wherein said cooling device is a heat pipe or vapor chamber, embedded in said platform. 23. A multi-level heat spreader, as in claim 22, wherein said cooling device is in the form of a vapor chamber, comprising wicking features, made of sintered material, wherein said sintered material is deposited onto inside wall surfaces of the vapor chamber, and at least one mound, said mound made of sintered material is provided within the vapor chamber, so that said mound would increase the rate of heat transfer of said vapor chamber, and wherein said vapor chamber allows additional fins to be attached to outside walls surfaces, so as to dispense heat outside the vapor chamber. 24. A multi-level heat spreader, as in claim 1, wherein the fist elongated elements are shaped to be curvilinear and parallel nested and oriented in a first orientation direction, and wherein the second elongated elements are also shaped to be curvilinear and parallel nested, and are oriented in a second orientation direction, whereinthe second orientation direction is in a different orientation direction from the first orientation direction, so as to provide a certain degree of flexibility between the primary heat source and the final heat dissipating device, said certain degree of flexibility provides multi-directional degrees of freedom. 25. A multi-level heat spreader, as in claim 10, wherein the elongated elements are joined to their respective heat source and platform, by soldering or gluing, and wherein said elongated elements have a coating along their length, except for the foot and the head of said elongated elements, so that the coating material would not interfere with the process of joining said elongated elements to their respective heat source or platform. 26. A multi-level heat spreader, as in claim 22, wherein the vapor chamber comprises a serpentine coil, allowing certain coolant to flow through the serpentine coil, to enhance the cooling effect of the vapor chamber. 27. A multi-level heat spreader, as in claim 1, wherein at least one of the first level and second level heat spreader units comprises a flexible sleeve, wherein said flexible sleeve surrounds and encapsulates the first and second elongated elements, and a heat conductive fluid filler is inserted within the flexible sleeve, between the first, second heat conducting platforms and upper stage platforms and around the elongated elements, to further enhance the effectiveness of the heat spreader units. 28. A multi-level heat spreader, as in claim 1, wherein at least one of the heat spreader units comprises a flexible sleeve, wherein said sleeve contains a heat conducting gel-like material, wherein said gel-like material totally removes and replaces the elongated elements, to provide a greater amount of flexibility between the primary heat source and the final heat dissipating device, and wherein support means are provided to support the first level and second level heat spreader units, between the primary heat source and the final heat dissipating device.