WO2016164044A1

WO2016164044A1 - Thermal couplers

Info

Publication number: WO2016164044A1
Application number: PCT/US2015/025405
Authority: WO
Inventors: David A Moore; Cl YANG; Kent E BIGGS
Original assignee: Hewlett Packard Development Co LP
Current assignee: Hewlett Packard Development Co LP
Priority date: 2015-04-10
Filing date: 2015-04-10
Publication date: 2016-10-13
Anticipated expiration: 2017-10-10

Abstract

In examples provided herein, a thermal coupler for electronic device with a heat management system includes a thermal baseplate and a corresponding heat transfer element. The thermal baseplate element include engagement rails coupled to a baseplate element. The engagement rails are disposed parallel and at a distance to one another. The baseplate element can also include a screw boss with a through-hole positioned between the engagement rails. The thermal transfer element can be disposed between the engagement rails and coupled to the baseplate element by a screw disposed through the screw boss.

Description

THERMAL COUPLERS

BACKGROUND

[0001] Electronic components, from computer processors to radio transmitters, generate heat during operation. Such heat can build up and potentially damage or degrade the performance of an electronic component and neighboring electronic components. For example, the heat generated by a computer processor in a particular computing device, such as a smart phone, tablet computer, laptop computer, or the like, can damage the memory, power system, display, or other components of the computing device. To avoid potential performance degradation or component damage, electronic devices often include various heat management components, such as heat sinks, heat pipes, fans, and the like.

BRIEF DESCRIPTION OF THE DRAWINGS

[0002] FIG. 1A depicts a perspective view of an example thermal baseplate.

[0003] FIG. 1 B depicts an example thermal baseplate with a through-hole to accommodate an electronic component.

[0004] FIG. 1C depicts an example thermal baseplate with a cutout to accommodate an electronic component.

[0005] FIG.2 depicts an example thermal baseplate and an example corresponding thermal transfer element.

[0006] FIG. 3 depicts assembly of an example thermal baseplate and an example corresponding thermal transfer element.

[0007] FIG.4 depicts an example thermal transfer element coupled to a liquid filled radiator.

[0008] FIG. 5 is a flowchart of an example method of assembling an electronic device having a thermal baseplate and a corresponding thermal transfer element. DETAILED DESCRIPTION

[0009] The present disclosure broadly discloses apparatuses and methods for assembling heat management systems in electronic devices, such as tablet computers, smart phones, laptop computers, or similar devices. In various implementations, the apparatus includes a two-part coupling mechanism for thermally coupling a heat source, such as a computer processor or other electronic component, to a heat management device, such as a heat sink or radiator, that is attached to or integrated into the exterior housing of an electronic device. For example, the heat management device can include a liquid filled radiator that is integrated into the back housing of a tablet computer to efficiently dissipate heat to the surrounding environment.

[0010] To ensure thermal coupling between the two-parts of the coupling mechanism, pressure perpendicular to the coupling surfaces can be applied. In various implementations, the pressure is applied by coupling inclined planes of one part of the coupling mechanism with correspondingly inclined planes of the second part of the coupling mechanism, such that when the two parts are moved in a plane parallel to the coupling surfaces, the coupling surfaces are pressed or wedged together with a compressive force. In some implementations, the pressure to engage the corresponding inclined planes can be supplied by a screw or bolt that pulls or pushes the two parts relative to one another in a direction parallel to the coupling surfaces. In one particular implementation, a spring element can be disposed between the screw and the two parts of the coupling mechanism to limit the force with which the inclined planes engage one another, and, consequently, the force with which the coupling surfaces are pressed together. Use of the spring to limit the coupling force can protect the components of the electronic devices, such as the processor, the externally exposed heat management device, the

motherboard, and the like, from strain or damage.

[0011] To simplify the exterior of the housing, the screw that exerts the force to engage the two parts of the coupling mechanism can be accessed through a single hole in the exterior surface of the housing. In some examples, the screw access hole can be included in a surface of the housing so as to not interfere with the externally exposed heat management element in another surface of the housing. Accordingly, holes in the externally exposed heat management element integrated into the housing of the electronic device can be reduced or eliminated.

[0012] FIG. 1 A depicts a perspective view of one part of an example two- part thermal coupling mechanism, according to various implementations of the present disclosure. Part 100, also referred to herein as a "thermal baseplate", can include or be made up of any thermally conductive material, such as metal, thermally conductive plastics, thermally conductive resins, and the like.

[0013] Thermal baseplate 100 can be dimensioned and include features to fasten to any internal structure of an electronic device. For example, thermal baseplate 100 can include a baseplate element 111 that can be coupled to an internal structure using fasteners (e.g., screws, rivets, tabs, etc.) disposed in through-holes 109. Accordingly, the through-holes 109 can be dimensioned and arranged within the baseplate element 111 to match up with

corresponding elements in the interior of an electronic device. For example, the through-holes 109 can be arranged and dimensioned to match up with corresponding threaded holes, unthreaded holes, standoffs, pegs, tabs, or clips included in an internal circuit board or other internal element of the electronic device housing. In some implementations, the through-holes 109 can accommodate fasteners for attaching the thermal baseplate 100 directly to a circuit board or electronic component of the electronic device. Such fasteners can include screws, bolts, rivets, clips, snaps, and the like.

[0014] In various implementations, the bottom surface (not shown) of the thermal baseplate 100 can be thermally coupled to a heat source element, such as a heat producing electronic component or power source (e.g., a power supply, an inverter, a transformer, a battery, a general purpose computer processor, a system-on-chip, an application-specific integrated circuit or "ASIC", etc.). In some implementations, the bottom surface of the baseplate element 111 can be coupled to a heat sink element that is in turn coupled to a heat source element. All such heat producing electronic components or correspondingly coupled heat sinks are referred to herein generally as "heat source elements". Accordingly, the bottom surface of the baseplate element 111 can be thermally coupled to the heat source element by direct physical contact or through an intermediate substance or structure. For example, the bottom surface of the baseplate element 111 can be thermally coupled to the heat source element by a thermally conductive lubricant, such as oil, grease, gel, liquid, or the like. As used herein, two elements are thermally coupled with one another when a path for conducting heat from one element to another is created. For example, two elements can be thermally coupled when thermally conductive, also referred to as heat conductive, materials are placed in direct physical contact with one another. In some implementations, thermally coupled elements may be stacked or chained together to create a thermally conductive path from one element to another element through one or more intermediate elements.

[0015] In various examples, the force that thermally couples the bottom surface of the baseplate element 111 to a heat source element can be achieved by various types of fasteners or couplers. For example, the force to thermally couple the bottom surface of baseplate element 111 can be provided by screws disposed in through-holes 109 that engage threaded holes in or around the heat source element. As used herein, thermal coupling can be achieved by direct physical contact between parts or by an indirect contact through another thermally conductive component or substance.

[0016] As shown in FIG. 1 A, the top surface 120 of the base plate element of the baseplate element 111 can include or be coupled to engagement rails 108. The engagement rails 108 can be dimensioned, arranged, and separated from one another according the size, dimensions, and/or configuration of a corresponding thermal transport element described herein. Accordingly, the engagement rails 108 can include a riser element of a particular height to separate the top platform element 105 away from the top surface 120 of the baseplate element so that the inclined surface 107 is disposed at a distance from the top surface 120 of the baseplate element 111 to accommodate a corresponding inclined surface of a thermal transfer element. For example, engagement rails 108 can include an L -shaped extrusion in which the platform element 105 is thinner or thicker on one side or the other. As shown, the difference in the thickness of the platform element 105 can provide for the slope of the inclined surface 107. The slope of the inclined surface 107 can be dimensioned and arranged relative to the top surface 120 of the baseplate element 111 to match inclined surfaces on a corresponding thermal transfer element.

[0017] The example thermal baseplate 100 can include a screw boss 110. In the particular example shown, the screw boss 110 is coupled to the top surface 120 of baseplate element 111 and includes a through-hole 115. In other implementations, the screw boss can be disposed on or coupled to another surface, such as the back edge, of the thermal baseplate 100. Again, as with the dimensions and arrangement of the other elements of the thermal baseplate 100, the size, position, orientation, and other physical attributes of the screw boss 110, such as the size of the through-hole 115, can correspond to the configuration of a corresponding thermal transfer element. For example, for a thermal transfer element having a threaded hole of a particular diameter and thread count disposed in the middle of its mass, the screw boss 110 can be positioned, as shown, centered between the engagement rails 108 with a correspondingly sized diameter through-hole 115.

[0018] FIG. 1 B depicts another example thermal baseplate 101. Thermal baseplate 101 includes features similar to those described above in reference to thermal baseplate 100 depicted in FIG. 1A. In addition, the example thermal baseplate 101 includes a baseplate element 111 having a cutout 121 in the top surface 120. The cutout 121 can be dimensioned to accommodate a heat source element 123, such as the integrated circuit shown. As described herein, the heat source element 123 can include a general purpose or specialized processor, an ASIC, a memory, a communication module, and the like.

[0019] In some implementations, the cutout 121 is a hole through the baseplate element 111 extending from top surface 120 to the bottom surface. In such implementations, the thermal baseplate 101 can be disposed around the heat source element 123. In other implementations, the cutout 121 can include a recessed region that extends only partially from the top surface 120 toward the bottom surface of the thermal baseplate 101. For example, the cutout region 121 can include a depression or indentation and through-holes to accommodate the electrical leads of the heat source element 123. In such implementations, the bottom surface of the recessed region of the cutout 121 can make thermal contact with a bottom surface of the heat source element 123. Accordingly, the thermal baseplate 101 can conduct heat away from the bottom surface of the heat source element 123.

[0020] FIG. 1C depicts another example thermal baseplate 102. Example thermal baseplate 102 baseplate element 111 can include a U-shaped cutout 122. The U-shaped cutout 122 can include an absence of a thermally conductive material of which some or all of the baseplate element 111 is composed.

[0021] While example thermal baseplates 100, 101 , and 102, include two engagement rails 108, other base plates according to other implementations of the present disclosure can include more or fewer than two engagement rails 108. For example, a thermal baseplate can include a single T-shaped engagement rail having a platform surface and inclined surface that extends off both sides of a unitary riser element. Such T-shaped engagement rails can correspond to a T-shaped slot with inclined surfaces in a heat transfer element

[0022] FIG. 2 depicts components of an example two-part thermal coupling mechanism, according to various examples of the present disclosure. As shown, the example thermal coupling mechanism can include a thermal transfer element 200 and a thermal baseplate 100. Each of the thermal transfer element 200 and the thermal baseplate 100 can be individual unitary structures. For example, thermal baseplate 200 and thermal transfer element 100 can be cast or milled as unitary structures from a thermally conductive material.

[0023] As described herein, the baseplate element 111 of thermal baseplate 100 can include a top surface 120 that includes a thermally conductive material. On either side of the top surface 120, the thermal baseplate can include L-shaped engagement rails 108. The L-shaped engagement rails 108 can include a platform element 105 disposed at a distance from the top surface 120 by a riser element 106. The platform elements 105 of each engagement rail 108 can extend inward and/or toward one another (e.g., toward a region above the top surface 120)

[0024] On a surface proximate to the top surface 120 (e.g., the bottom surface of the platform element 105), the platform elements 150 can include inclined surfaces 107. The signs and magnitudes of the slope of inclined surfaces 107 can correspond (e.g., match) to the signs and magnitudes of the slope of inclined surfaces 207 on the thermal transfer element 200. Similarly, the widths of the inclined surfaces 107 and 207 can be dimensioned to match one another. Similarly, the external width W 235A of the thermal transfer element 200 can be dimensioned to match or fit the internal width W 235B between the internal surfaces of the riser elements 106 of the thermal baseplate 100. For example, the widths W 235A and W 235B can to be dimensioned to allow for the thermal transfer element 200 to slide into the thermal baseplate 100 between riser elements 106. The lengths of the thermal transfer element 200 and the thermal baseplate, N 230 and L 240, can be equal or unequal.

[0025] FIG. 3 illustrates the insertion of an example thermal transfer element 200 into the thermal baseplate 100. The thermal transfer element 200 can include or be made up of a thermally conductive material. Accordingly, the thermal transfer element 200 can conduct heat from the thermal baseplate 100 and/or any other component with which is in thermal conductive contact.

[0026] When inserted into the thermal baseplate 100, the bottom surface 220 of the thermal transfer element 200 moves parallel to the surface 120. Simultaneously, inclined surfaces 207 and 107 engage one another. Based on the slope of the inclined surfaces 207 and 107, the bottom surface 220 is pressed against the top surface 120. The normal force exerted by surfaces 220 and 120 on one another can increase with the degree to which the thermal transfer element 200 is inserted into the thermal baseplate. The normal forces on surfaces 220 and 120 can create a thermal interface between the thermal baseplate 100 and thermal transfer element 200.

Similarly, in thermal base plates, such as 101 and 102, in which the associated heat source element 123 sits at or above surface 120, such as in example thermal base plates 101 and 102, the bottom surface 220 of the thermal transfer element 200 can contact the top surface of the heat source element 123 and/or top surface 120 of the thermal baseplate. Accordingly, the bottom surface 220 can be thermally coupled directly to the top surface of the heat source element 123.

I0027J Once the thermal transfer element 220 is inserted sufficiently far into the thermal baseplate 100, the thermal connection between the two elements can be fastened by inserting a screw 180 into the through-hole 115 of the screw boss 110 to engage the correspondingly threaded hole 185, The force exerted on the thermal transfer element 200 by the screw 180 and screw boss 1 10 can maintain a force such that the corresponding inclined surfaces 107 and 207 cause the bottom surface 220 to be pressed against the top surface 120, and/or the top surface of the heat source element 123, to ensure thermal contact. In some implementations, the force transferred by the screw to the surfaces 120 and 220 can be limited by using a screw 180 that will fully insert into hole 185 (e.g., bottom-out) and including a spring around the screw 180 between the head of the screw and the screw boss, !n such implementations, the force can be limited by the characteristics of the spring, thus protecting other components to which the thermal transfer element 200 and the thermal baseplate 100 are coupled from mechanical stress or strain.

[0028] As described herein, the thermal connection between the thermal transfer element 200 and the thermal baseplate 100 can be used to thermally couple a heat source element 123 to an externally exposed heat management element in an electronic device. For example, FIG. 4 depicts the heat transfer element 200 coupled to a liquid filled radiator 300 that can be included in an external surface of a housing of an electronic device. In the example shown, the liquid filled radiator 300 can include a heat conductive materia! 320 having multiple liquid filled channels 350, through which a cooling fluid can be circulated to dissipate heat. In such implementations, the surface 325 (e.g., the bottom surface of the liquid filled radiator 300} can be exposed to the air on the outside of an electronic device. For example, the surface 325 can make up a portion of the back surface of the housing of a tablet computer. [0029] In various implementations, to avoid mechanical fasteners, the surface opposite the bottom surface 220 of the transfer element 200 can be adhered to a surface of the liquid filled radiator 300 that will face the interior of the electronic device. Adhering the thermal transfer element 200 to the interior surface of the liquid filled radiator 300 can include coupling the thermal transfer element 200 to the surface using a thermally conductive adhesive or welding the two elements together.

[0030] In implementations in which the liquid filled radiator 300 is included into the exterior housing of an electronic device, the electronic device can be assembled and held together by the thermal transfer element 200 being coupled to the thermal baseplate 100 as described herein. Accordingly, at least some portion of the electronic device can be assembled using two separate subassemblies. One subassembly of the electronic device can include the thermal baseplate 100 and the heat source element 123 and the other electronic components to which it is coupled. In some implementations, the thermal baseplate 100 and the heat source element 123 can also be coupled to another part of the housing of the electronic device (e.g., a front facing portion of the housing). Another subassembly of the electronic device can include a housing that includes the liquid filled radiator 300 (e.g., the back panel of the housing) and the thermal transfer element 200. The two subassemblies can be joined by inserting the thermal transfer element 200 into the thermal baseplate 100. In one example assembly process, the subassembly that includes the thermal transfer element 200 can be moved in a direction parallel to the bottom surface 220 and top surface 120 of the thermal baseplate 100 in the other subassembly to engage the corresponding inclined surfaces 107 and 207. The insertion of the thermal transfer element 200 into the thermal baseplate 100 can create a thermal and structural connection between the two subassemblies. Accordingly, the thermal connection between the thermal transfer element 200 and the thermal baseplate 100 can create a thermal coupling between the liquid filled radiator 300 and a heat source element 123.

[0031] According to various implementations of the present disclosure, the coupling of the thermal transfer element 200 to the thermal baseplate 100 can provide for a reliable thermal coupling between the heat source element 123 and the liquid filled radiator 300, or other heat management elements, without fasteners extending through the exterior surface of the heat management element toward the heat source element 123. Accordingly, various

implementations allow for externally exposed heat management elements, such as liquid filled radiator 300, to be exposed on the exterior or included in the housing of electronic device without externally exposed mechanical fasteners, such as screws, rivets, bolts, and the like. Instead, the force that exerts the normal force between the thermally conductive surfaces 220 and 120 of the thermal transfer element 200 and the thermal baseplate 100 can be provided by the lateral force provided by screw 180 that is translated into a transverse force by the corresponding inclined services 107 and 207. The screw 180 can be exposed to the exterior of the housing through a solitary hole on the edge of the housing of the electronic device along with other ports (e.g., data ports, charging ports, etc.) and openings (e.g., speaker holes, headphone jacks, microphone holes, etc.) in the housing.

[0032] FIG. 5 is a flowchart of a method 500 for assembling an electronic device that includes a thermal transfer element 200 and a thermal baseplate 100. The can include using the thermal transfer element 200 and the thermal baseplate 100 to establish a thermal connection between an externally exposed heat management element and an internal heat source element. As shown, method 500 can begin at box 510 in which a thermal transfer element 200 coupled to an externally exposed heat management element is positioned relative to a thermal baseplate 100 coupled to a heat source element 123. Positioning the thermal transfer element 200 relative to the thermal baseplate 100 can include aligning corresponding inclined planes for coupling.

[0033] As described herein, an externally exposed heat management element, such as liquid filled radiator 300, can be included in the exterior housing of an electronic device. Similarly, the heat source element 123 can include any electronic component of the electronic device, such as a computer processor, memory, radio transceiver, and the like. In such implementations, the heat source element can be coupled to a circuit board (e.g., a motherboard) disposed within a portion of the housing of the electronic device. Accordingly, positioning the thermal transfer element 200 relative to the thermal baseplate 100 can include positioning a back section of the housing, having the externally exposed heat management element and the thermal transfer element 200, in a parallel but offset position relative to a front section of the housing that includes the thermal baseplate 100 and heat source element 123. In this position, the interface surfaces (e.g., surfaces 220 and 120) of the thermal transfer element 200 and the thermal baseplate 100 can be parallel and approximately coplanar, but offset from one another.

[0034] At box 520, the thermal transfer element 200, along with the externally exposed heat management element, can be moved, or slid, in a direction parallel to the interface surfaces to engage the corresponding inclined surfaces 207 and 107 on the thermal transfer element 200 and the thermal baseplate 100 to thermally couple the heat source element 123 with the externally exposed heat management element.

[0035] In related implementations, the method 500 can also include inserting a screw 180 through a hole in an exterior surface of the housing of the electronic device and the through-hole 115 in the screw boss 110 to engage the corresponding threaded hole 185 in the thermal transfer element 200. The screw 180 can then be torqued to exert force parallel to the interface surfaces so that the inclined surfaces 207 and 107 exert a force on one another that is transferred as a force normal to the interface surfaces to create a thermal coupling. In some implementations, the interface surfaces can be lubricated with a heat conductive gel, oil, grease, or the like to facilitate easy insertion of the thermal transfer element 200 into the thermal baseplate 100 and/or create a good thermal connection.

[0036] These and other variations, modifications, additions, and improvements may fall within the scope of the appended claims(s). As used in the description herein and throughout the claims that follow, "a", "an", and "the" includes plural references unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of "in" includes "in" and "on" unless the context clearly dictates otherwise. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and/or all of the elements of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and/or elements are mutually exclusive.

Claims

Claims What is claimed is:

1. A thermal coupler, comprising:

a baseplate element;

a first engagement rail coupled to the baseplate element;

a second engagement rail coupled to the baseplate element and disposed at distance to and parallel to the first engagement rail;

a screw boss comprising a through-hole and coupled to the baseplate element between the first engagement rail and the second engagement rail; and

a thermal transfer element disposed between the first engagement rail and the second engagement and coupled to the baseplate element by a screw disposed through the screw boss.

2. The thermal coupler of claim 1 , wherein the first engagement rail comprises a first riser element and a first platform element, the first platform element coupled to the first riser element at a first distance from the baseplate element and extending toward the second engagement rail, the second engagement rail comprises a second riser element and a second platform element, the second platform element coupled to the second riser element at a second distance from the baseplate element and extending toward the first engagement rail.

3. The thermal coupler of claim 1 , further comprising a liquid filled radiator coupled to the thermal transfer element.

4. The thermal coupler of claim 3, wherein the liquid filled radiator element comprises at least part of a housing for an electronic device.

5. The thermal coupler of claim 1 , wherein the first engagement rail and the second engagement rail comprise inclined surfaces that correspond to inclined surfaces on the thermal transfer element that cause a first surface on the baseplate element to be pressed against a second surface on the thermal transfer element when the thermal transfer element is pushed in a direction parallel to the first surface on the baseplate element and the second surface on the thermal transfer element.

6. The thermal coupler of claim 5, wherein the first surface on the thermal baseplate and the second surface on the thermal transfer element are thermally coupled by a thermally conductive lubricant.

7. The thermal coupler of claim 1 , wherein the baseplate element comprises a cutout to accommodate a heat source element, and the thermal transfer element is disposed to make thermally conductive contact with the heat source element.

8. The thermal coupler of claim 1 , wherein the baseplate element, the first engagement rail, and the second engagement rail are formed as a single unitary structure and comprise a thermally conductive material.

9. A computing device, comprising:

a housing comprising an externally exposed heat management element;

a heat source element coupled to the housing;

a baseplate element coupled to the heat source element;

a first engagement rail coupled to the baseplate element;

a second engagement rail coupled to the baseplate element and disposed at a distance to and parallel to the first engagement rail; and

a thermal transfer element thermally coupled to the heat source element by the first engagement rail and the second engagement rail and thermally coupled to the externally exposed heat management element.

10. The apparatus of claim 9, wherein the heat source element comprises an integrated circuit.

11. The computing device of claim 9, wherein the first engagement rail and the second engagement rail comprise inclined surfaces that correspond to inclined surfaces on the thermal transfer element that cause a first surface on the baseplate element to press against a second surface on the thermal transfer element when a force is applied to the thermal transfer element in a direction parallel to the first surface on the baseplate element and the second surface on the thermal transfer element.

12. The computing device of claim 9, wherein the heat source element is a processor.

13. A method comprising:

positioning a thermal transfer element of a thermal coupler coupled to an externally exposed heat management element of a first section of a housing relative to a thermal baseplate coupled to a heat source element disposed in a second section of the housing in alignment for coupling; and sliding the thermal transfer element in a direction parallel to an interface between the thermal baseplate and the heat source element to engage corresponding inclined surfaces on the thermal transfer element and the thermal baseplate to thermally couple the heat source element with the externally exposed heat management element.

14. The method of claim 13, further comprising

inserting a screw through an hole in an exterior surface of the first section or second section of the housing, the hole being aligned with a screw boss coupled to the thermal baseplate; and

securing the thermal transfer element to the thermal baseplate with the screw to exert a force in the direction parallel to the interface that causes compressive force between the corresponding inclined surfaces.

15. The method of claim 13. further comprising applying a thermally

conductive lubricant to the thermal baseplate or the thermal transfer element.