US20130032324A1

US20130032324A1 - Thermal solution with spring-loaded interface

Info

Publication number: US20130032324A1
Application number: US13/478,328
Authority: US
Inventors: Russell W. Aldridge; Richard G. Baldwin, Jr.; Jeremy P. O'Rarden; Nathan G. Coon; Dennis Vance Toth
Original assignee: Individual
Current assignee: National Instruments Corp
Priority date: 2011-08-03
Filing date: 2012-05-23
Publication date: 2013-02-07

Abstract

Thermal solution systems including a heat sink and a spreader plate mounted to the heat sink via one or more springs. Thermal gap filler provides a thermal interface between the heat sink and the spreader plate. The one or more springs provide contact force between the heat spreader plate and a component to be cooled, while accommodating dimensional variation, such as manufacturing tolerance or assembly tolerance related variation.

Description

This application claims benefit of priority to U.S. Provisional Patent Application No. 61/514,610, filed Aug. 3, 2011. The preceding provisional application is incorporated herein by reference in its entirety.

BACKGROUND

1. Technical Field
This disclosure relates to the field of thermal solutions, and more particularly to heat sinks for use in cooling high energy density, thermally sensitive components.
2. Description of the Related Art
Heat sinks may be used for cooling thermally-sensitive, high energy density components by providing a means for transferring generated heat away from those components. Examples of high energy density components include processors, chipsets, and field-programmable-gate-arrays (FPGAs).
A thermal solution system may include a gap pad disposed between a heat sink and a heat-generating component to facilitate heat transfer between the heat-generating component and the heat sink. Reducing the thickness of the gap pad, and/or increasing compression that the gap pad experiences may reduce the thermal resistance within the thermal solution system.
High energy density components may be connected to printed circuit boards (PCBs) using solder connections. Applying excessive pressures to such PCB-mounted components (e.g., to compress a gap pad disposed between a heat sink and a PCB-mounted component) may damage the PCB and/or the solder joints used to mount the component to the PCB.

SUMMARY

Various embodiments of a thermal solution are presented below.
In one embodiment, an apparatus may include a heat sink, heat sink spreader plate, and a first thermally conductive filler material. The heat spreader plate may be mounted to the heat sink using one or more springs, and the first thermally conductive filler material may be disposed between the heat sink and the heat spreader plate. Some embodiments of the apparatus may be configured to transfer heat from a component to be cooled, where transferring the heat includes interfacing with the component to be cooled via the heat spreader plate, and where the interfacing includes the heat spreader plate receiving force via the component to be cooled, where the received force causes compression of the one or more springs.
In some embodiments, receiving the force from the component includes receiving the force from the component via a second thermally conductive filler material that is disposed between the component and the heat spreader plate. Various embodiments may have a second thermally conductive filler material that includes a thermal gap pad.
Particular embodiments of the present disclosure may include a first thermally conductive filler material that includes a thermally conductive liquid gap filling material. In other exemplary embodiments, the first thermally conductive filler material may include a thermal gap pad.
In some embodiments, the one or more springs may include one or more wave springs. In various embodiments, the one or more the wave springs may have an inner circumference and an outer circumference, and the first thermally conductive filler material may be disposed between the heat sink and the heat spreader plate, within the inner circumferences of the one or more wave springs.
In some embodiments, the one or more springs may include one or more coil springs. Some embodiments may include one or more leaf springs as part of the one or more springs.
In one embodiment, a thermal solution device may include a main body, an interface plate, one or more springs mounting the interface plate to the main body, and a thermally conductive filler material disposed between the main body and the interface plate. In some cases, the thermal solution device may be configured to transfer heat from a component to be cooled by interfacing, using the interface plate, with the component to be cooled. Such interfacing may cause compression of the one or more springs.
One embodiment of a thermal solution device may include a heat sink, a plurality of heat spreader plates mounted to the heat sink respectively using one or more springs, one or more thermally conductive filler materials disposed between the heat sink and individual ones of the plurality of heat spreader plates. In some cases, the thermal solution device may be configured to mount to a system that includes a plurality of components to be cooled. Mounting to the system may cause the individual ones of the plurality of heat spreader plates to respectively interface with individual ones of the plurality of component to be cooled.
In some embodiments, the interfacing may include individual ones of the plurality of heat spreader plates respectively receiving pressure from the individual ones of the plurality of components to be cooled. Such receiving of pressure may cause compression of the respective one or more springs.
In various embodiments, the individual ones of the plurality of components to be cooled may include a processor. In some embodiments, the individual ones of the plurality of components to be cooled include a printed circuit board.
Some embodiments of the present disclosure may include a particular one of the plurality of heat spreader plates that is configured to remove heat generated by processors by interfacing with a first side of the printed circuit board. The first side may be opposite of a second side of the printed circuit board, where the second side may have the processor mounted thereon.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description makes reference to the accompanying drawings, which are now briefly described.

FIG. 1 illustrates one embodiment of the present disclosure. In the depicted embodiment, a spring-mounted heat spreader plate is used in providing an interface between a heat sink and a component to be cooled. The depicted heat sink includes fins for dissipating heat.

FIG. 2 illustrates an exemplary embodiment of the present thermal solution. In the depicted embodiment, an interface between a heat sink and a component to be cooled is implemented using a plurality of springs and shoulder screws. As shown, a system back panel may be used as a heat sink for dissipating heat.

FIG. 3 depicts an embodiment of the present disclosure in which a wave spring is used in mounting a heat spreader plate. The heat spreader plate is used in providing an interface between a heat sink and a processor.

FIG. 4 illustrates the heat spreader plate, wave spring, and heat sink of the embodiment depicted in FIG. 3. Components to be cooled (e.g., processor, PCB) are not depicted in this figure.

FIG. 5 shows a thermal solution that includes several heat spreader plates that may be used for providing interfaces between one heat sink and several components to be cooled.

FIG. 6 illustrates an exemplary embodiment in which a heat spreader plate includes features that may interface with a PCB, as well as with a processor mounted on the PCB.

FIG. 7 depicts one embodiment of the present disclosure configured such that the heat spreader plate may interface with a printed circuit board having a processor (or other heat-generating component) mounted on an opposite side of the PCB. Such configurations may be useful in cases where it is not feasible to interface directly to the heat-generating component.

Specific embodiments are shown by way of example in the drawings, and will be described herein in detail. It should be understood, however, that the drawings and detailed description are not intended to limit the claims to the particular embodiments disclosed, even where only a single embodiment is described with respect to a particular feature. On the contrary, the intention is to cover all modifications, equivalents and alternatives that would be apparent to a person skilled in the art having the benefit of this disclosure. Examples of features provided in the disclosure are intended to be illustrative rather than restrictive unless stated otherwise.
The headings used herein are for organizational purposes only and are not meant to be used to limit the scope of the description. As used throughout this application, the word “may” is used in a permissive sense (i.e., meaning having the potential to), rather than the mandatory sense (i.e., meaning must). The words “include,” “including,” and “includes” indicate open-ended relationships and therefore mean including, but not limited to. Similarly, the words “have,” “having,” and “has” also indicated open-ended relationships, and thus mean having, but not limited to. The terms “first,” “second,” “third,” and so forth as used herein are used as labels for nouns that they precede, and do not imply any type of ordering (e.g., spatial, temporal, logical, etc.) unless such an ordering is otherwise explicitly indicated. For example, a “third heat spreader plate” receiving force does not preclude scenarios in which a “fourth heat spreader plate” receives force prior to, or simultaneously to, the third heat spreader plate, unless otherwise specified. Similarly, a “second” feature does not require that a “first” feature be implemented prior to the “second” feature, unless otherwise specified.
Various components may be described as “configured to” perform a task or tasks. In such contexts, “configured to” is a broad recitation generally meaning “having structure that” performs the task or tasks during operation. As such, the component can be configured to perform the task even when the component is not currently performing that task (e.g., a spring may be configured to compress due to received force, even when that force is not being received). In some contexts, “configured to” may be a broad recitation of structure generally meaning “having circuitry that” performs the task or tasks during operation. As such, the component can be configured to perform the task even when the component is not currently on. In general, the circuitry that forms the structure corresponding to “configured to” may include hardware circuits.
Various components may be described as performing a task or tasks, for convenience in the description. Such descriptions should be interpreted as including the phrase “configured to.” Reciting a component that is configured to perform one or more tasks is expressly intended not to invoke 35 U.S.C. §112, paragraph six, interpretation for that component.
The scope of the present disclosure includes any feature or combination of features disclosed herein (either explicitly or implicitly), or any generalization thereof, whether or not it mitigates any or all of the problems addressed herein. Accordingly, new claims may be formulated during prosecution of this application (or an application claiming priority thereto) to any such combination of features. In particular, with reference to the appended claims, features from dependent claims may be combined with those of the independent claims and features from respective independent claims may be combined in any appropriate manner and not merely in the specific combinations enumerated in the appended claims.

DETAILED DESCRIPTION OF EMBODIMENTS

This specification includes references to “one embodiment” or “an embodiment.” The appearances of the phrases “in one embodiment” or “in an embodiment” do not necessarily refer to the same embodiment. Particular features, structures, or characteristics may be combined in any suitable manner consistent with this disclosure.
Turning to FIGS. 1-7, some embodiments of the present disclosure may include heat spreader plate 130 that may be mounted to heat sink 110 using one or more springs. The one or more springs (spring 120) may in some cases include a wave spring (see FIGS. 3-5). In some embodiments, the one or more springs may additionally or alternately include other types of springs, or combinations of springs (e.g. coil springs, leaf springs, cantilever springs, foam, formed sheet metal structures, molded plastic structures). As illustrated in FIG. 2, in some cases, spring 120 may be configured to be disposed over fastener 125 that couples heat spreader plate 130 to heat sink 110 (which in the depicted embodiment is a back panel). In various embodiments, spring 120 may include any structure and/or material that outputs force in response to compression and/or elongation.
Spring 120 may serve to apply force against heat spreader plate 130, holding heat spreader plate 130 against component to be cooled 210 (e.g., CPU, GPU, FPGA, portion of PCB) at an optimal minimum bond line thickness, between heat spreader plate 130 and the component 210, for thermally conductive filler material 150.
Thermally-conductive gap filler material 140 may in some cases be used between heat sink 110 and heat spreader plate 130 to provide desirable thermal conductivity, while providing for adjustment in location of heat spreader plate 130 relative to heat sink 110 and/or relative to component 210 (e.g., via variation in compression of spring 120). Such adjustability in the heat spreader plate location may accommodate dimensional variations, such as variations resulting from manufacturing tolerance and/or assembly tolerance stack up.
In some embodiments, a thermally conductive liquid-dispensed gap filling material may be used as the gap filler material 140 between heat sink 110 and heat spreader plate 130. In some embodiments, high thermal performance liquid-dispensed gap filling materials that cure to a low modulus elastomer may be used as gap filler material 140. In some embodiments, a thermal gap filler that includes a silicone gel may be used as gap filler material 140. In various embodiments, a high thermal-performance gap-filling pad or putty may be used as gap filler material 140.
For example, a particular embodiment may include gap filler material 140 comprising and/or formed from a thermally-conductive liquid gap filler having a relatively low viscosity (100,000 to 200,000 cps) prior to curing. Subsequent to curing, a compliant material may be formed for gap filler material 140 that is similar to typical gap pad, but having a higher thermal conductivity. Such a liquid gap filler that flows during assembly may provide for desirable thermal conductivity, while avoiding excessive contact force on the component 210's die, and/or strain in surrounding and supporting structures, such as a printed circuit board (PCB 220). Once cured, the compliant thermal material in this embodiment of gap filler material 140 may in some cases further act as a damper to restrain movement of heat spreader plate 130 during possible vibration on the system.
A same or different thermally-conductive filler material may be used as filler 150 between heat spreader plate 130 and the component to be cooled 210 (e.g., at a side or surface of heat spreader plate 130 that is opposite of heat sink 110) in various embodiments of the present disclosure. For example, filler 150 may include thermal grease or phase change materials to improve the thermal interface between heat spreader plate 130 and component 210. In some embodiments, filler 150 may include a thermal gap pad, epoxy, or liquid gap filler. In particular embodiments, various thermally-conductive materials that may be implemented with a thin bond line may be well-suited for use as, or as part of, filler 150.
In some embodiments, the one or more springs (spring 120) may be selected or designed to provide sufficient contact force to maintain heat spreader plate 130 in contact with component 210 at design shock levels, without exceeding maximum allowable forces applied to component 210 (e.g., forces at the component's die or solder joints).
The heat spreader plate 130 may be fabricated using various materials that are suitable for providing thermal conductivity (e.g., aluminum, copper). In some embodiments, heat spreader plate 130 may include various thermal solution features, such as, for example, integrated heat pipe, vapor chamber, etc. Some embodiments may include heat spreader plates 130 that are configured to interface with printed circuit board (e.g., PCB 220) for purposes of cooling an area of the printed circuit board that is near a heat-generating component, or other component to be cooled. For example, FIG. 7 depicts an embodiment in which heat spreader plate 130 interfaces with PCB 220 via filler 150, thereby removing heat from PCB 220 in an area that may otherwise experience elevated temperatures due to heat generated by component 210 (e.g., a processor) that is mounted on the opposite side of PCB 220 from heat spreader plate 130. Particular embodiments may also include heat spreader plates 130 that are configured to interface with a system board to provide proper orientation (e.g., gap spacing) with respect to a component 210 (e.g., CPU, GPU) mounted on the system board. See FIG. 6.
The heat sink 110 may also be fabricated using various materials that are suitable for providing thermal conductivity (e.g., aluminum, copper). The heat sink material may in some instances be the same as the heat spreader plate material. In other cases, the heat sink 110 and the heat spreader plate 130 may be of differing materials. Various embodiments of heat sink 110 may include various thermal solution features, such as, for example, fins, integrated heat pipe, vapor chamber, water cooling, etc.
Various embodiments of the present disclosure may include a heat sink 110 configured with a plurality of heat spreader plates 130 for interfacing with a plurality of components to be cooled. Such an embodiment may provide a single thermal solution for a plurality of components that are mounted on a single board or system, without requiring individual mounting locations on the board or system corresponding to each component to be cooled. For example, a system board may have heat-generating components including a CPU, GPU, and FPGA that each require cooling. In the exemplary system, compact design requirements may preclude providing mounting locations (e.g., locations for screws, clips, or standoffs) at the system board near the three components, thereby preventing the mounting of individual heat sinks to each of the three components and applying contact force to each. Various ones of the present embodiments may include a single, common heat sink 110 that mounts to the system board, and that also interfaces and provides contact force to each of the three components. In such a way, the need for individual heat sink mounting locations near the components to be cooled may be removed in favor of common heat sink mounting locations that may be located distant from the particular components to be cooled. For example, FIG. 5 depicts fastener locations 510 at the periphery of heat sink 110. These fastener locations 510 may be used to mount heat sink 110 to a system board or other structure, at locations that are relatively distant to the locations of the components to be cooled. In the depicted embodiments, heat spreader plates 130 may be mounted to heat sink 110 using fasteners 125 at fastener locations 520, which are relatively near to the components to be cooled.
FIG. 5 further illustrates an embodiment that includes springs 120 that are wave springs disposed between the heat spreader plates and the heat sink. As depicted, a single wave spring may correspond to the size of the heat spreader plate, and gap filler material 140 may be disposed within an inner circumference of the wave spring 120. Gap filler material 140 may in some cases also be disposed exterior to an outer circumference of the wave spring 120 (e.g., between wave spring 120 and features corresponding to a profile for the heat spreader plate). For example, FIGS. 3 and 4 illustrate embodiments in which heat sink 110 includes locating and retaining features, where gap filler material 140 is disposed within an inner circumference of wave spring 120, as well as outside of the outer circumference of wave spring 120. Other embodiments may include springs 120 comprising more than one wave spring, or one or more other types of springs, with gap filler material 140 appropriately disposed to provide thermal conductivity between the heat sink 110 and the spreader plate(s) 130.
Although the embodiments above have been described in considerable detail, numerous variations and modifications will become apparent to those skilled in the art once the above disclosure is fully appreciated. It is intended that the following claims be interpreted to embrace all such variations and modifications.

Claims

1. An apparatus, comprising:

a heat sink;

a heat spreader plate mounted to the heat sink using one or more springs; and

a first thermally conductive filler material disposed between the heat sink and the heat spreader plate;

wherein the apparatus is configured to transfer heat from a component to be cooled, wherein transferring the heat includes interfacing with the component to be cooled via the heat spreader plate, and wherein the interfacing includes the heat spreader plate receiving force via the component to be cooled, wherein the received force causes compression of the one or more springs.

2. The apparatus of claim 1, wherein the receiving the force from the component includes receiving the force from the component via a second thermally conductive filler material disposed between the component and the heat spreader plate.

3. The apparatus of claim 2, wherein the second thermally conductive filler material includes a thermal gap pad.

4. The apparatus of claim 1, wherein the first thermally conductive filler material includes a thermally conductive liquid gap filling material.

5. The apparatus of claim 1, wherein the first thermally conductive filler material includes a thermal gap pad.

6. The apparatus of claim 1, wherein the one or more springs includes a wave spring.

7. The apparatus of claim 6, wherein the wave spring has an inner circumference and an outer circumference, and wherein the first thermally conductive filler material disposed between the heat sink and the heat spreader plate is disposed within the inner circumference of the wave spring.

8. The apparatus of claim 1, wherein the one or more springs includes one or more coil springs.

9. The apparatus of claim 1, wherein the one or more springs includes one or more leaf springs.

10. A thermal solution device, comprising:

a main body;

an interface plate;

one or more springs mounting the interface plate to the main body; and

a thermally conductive filler material disposed between the main body and the interface plate;

wherein the thermal solution device is configured to transfer heat from a component to be cooled by interfacing, using the interface plate, with the component to be cooled, and wherein the interfacing causes compression of the one or more springs.

11. The thermal solution device of claim 10, wherein the thermally conductive filler material includes a thermal gap pad.

12. The thermal solution device of claim 10, wherein the thermally conductive filler material includes a thermally conductive liquid gap filling material.

13. The thermal solution device of claim 10, wherein the one or more springs includes a wave spring.

14. The thermal solution device of claim 10, further comprising:

an additional thermally conductive filler material disposed between the component and the heat spreader plate.

15. The thermal solution device of claim 14, wherein the additional thermally conductive filler material includes a thermal gap pad.

16. A thermal solution device, comprising:

a heat sink;

a plurality of heat spreader plates mounted to the heat sink respectively using one or more springs; and

one or more thermally conductive filler materials disposed between the heat sink and individual ones of the plurality of heat spreader plates;

wherein the thermal solution device is configured to mount to a system that includes a plurality of components to be cooled, wherein mounting to the system causes the individual ones of the plurality of heat spreader plates to respectively interface with individual ones of the plurality of component to be cooled.

17. The thermal solution device of claim 16, wherein the interfacing includes the individual ones of the plurality of heat spreader plates respectively receiving pressure from the individual ones of the plurality of components to be cooled to cause compression of the respective one or more springs.

18. The thermal solution device of claim 17, wherein the individual ones of the plurality of components to be cooled include a processor.

19. The thermal solution device of claim 17, wherein the individual ones of the plurality of components to be cooled include a printed circuit board.

20. The thermal solution device of claim 19,

wherein a particular one of the plurality of heat spreader plates is configured to interface with a first side of the printed circuit board;

wherein the first side is opposite of a second side of the printed circuit board, the second side having a processor mounted thereon; and

wherein the particular one of the plurality of heat spreader plates is configured to remove heat generated by the processor.