Replaceable electronic component with durable heat dissipation

Abstract

A system for thermal control of an optical module includes a thermally conductive interface having a polymer matrix and a thermally conductive particulate filler dispersed in the polymer matrix. The thermally conductive interface is positioned at a heat dissipating surface of the optical module and spaced from an exterior edge by a predetermined dimension. The system further includes a frame having a heat sinking surface that is configured to removably receive the optical module therein with the thermally conductive interface in contact with the heat sinking surface.

Description

2024P00344REPLACEABLE ELECTRONIC COMPONENT WITH DURABLE HEAT DISSIPATIONFIELD

[0001] The present invention relates to heat-generating replaceable electronic components generally, and more particularly to abrasion-resistant thermally conductive pads or films used in connection with the electronic components to reduce thermal impedance between the electronic device and a heat sink positioned for thermal contact with the thermally conductive pad when the replaceable electronic component is installed in a host device.BACKGROUND

[0002] Dissipating heat from heat-generating electronic components presents a continuing challenge for component manufacturers and system operators. Reliably dissipating heat over the course of operating lifetimes of electronic components, particularly for replaceable components that undergo significant abrasion during repeated installation and removal procedures, is an even greater challenge due to the damage that can be incurred to thermal transmission materials disposed at the surfaces exposed to abrading forces in use.

[0003] Example replaceable components include optical transceivers, such as a C-form-factor pluggable (CFP) optical transceiver, and a small form-factor pluggable (SFP) optical transceiver that can be installed in or removed from a modular host system. Such optical transceivers are “pluggable” in that they may be inserted and removed from the host device or system without removing power from the host device or system. The pluggable transceivers are typically received at receptacles defined by respective frames of the host system.

[0004] In order to prevent heat accumulation in the pluggable electronic components, heat sinking structures may be used in connection with the system receptacles to assist in dissipating heat from the electronic components. In typical embodiments, the heat sinking devices are in thermal contact with the components when installed in the receptacle so that heat may be conductively dissipated from the2024P00344component. The efficiency of the conductive heat transfer from the electronic component is limited in large part by the thermal impedance of the interface between the electronic component and the heat sinking structure. A common factor in the thermal impedance of interfaces between the heat-generating electronic component and the heat sinking structure is non-contact portions of the interface, wherein heat transfer by conduction is limited to only the portions of the contact region where the respective surfaces of the electronic component and the heat sinking structure actually make contact. Often, the contacting surfaces are metal and have unevenness that, combined with the surface rigidity, prevents widespread physical contact between the surfaces.

[0005] A known technique for reducing the thermal impedance at an interface between metal surfaces is to position a compliant or conformable thermally conductive material, such as a paste, gel, film, or pad at the interface. The most effective thermal interfaces are typically those which are most conformable to increase total contact surface area or conductive heat transfer. Such conformable thermal interface materials, while effective in static applications, cannot withstand the abrasion forces incurred in a dynamic setting, such as pluggable components, in which the heat generating device is repeatedly slid into and out from a receptacle in abrasive contact with the frame of the host system. As a result, the thermal interface material tends to degrade over a period of time due to the repeated installation and removal of the component. Degradation of the thermal interface material leads to an increase in thermal impedance to the transfer of heat from the electronic component to the heat sinking structure associated with the host system.

[0006] A need therefore exists for a durable thermal interface between a replaceable electronic component and a heat sinking structure of the host system.SUMMARY

[0007] A system for thermal control of an optic module having a heat-dissipating surface bound by an edge includes a thermally conductive interface having a first sheet and a second sheet. The first sheet extends between a first major surface and a second major surface, and includes a first non-silicone resin matrix and thermally conductive particulate filler dispersed in the first non-silicone resin matrix, wherein the thermally2024P00344conductive particulate filler comprises at least 50 wt.% of the first sheet. The second sheet is disposed at the first major surface of the first sheet, and the second sheet includes a second non-silicone resin matrix, wherein the second sheet is substantially free of thermally conductive particulate filler. The thermally conductive interface is disposed at the heat-dissipating surface of the optic module, and the thermally conductive interface has a thickness of between 0.01 and 3 mm. The system further includes a frame having a heat sinking surface and a receptacle that is configured to removably receive the optic module therein with the thermally conductive interface in contact with the heat sinking surface.

[0008] In some embodiments, the first resin matrix and the second resin matrix each include acrylic-based polymers, and the thermally conductive particulate filler is selected from at least one of boron nitride and graphite.

[0009] In some embodiments, the edge includes a front edge extending between a first end and a second end, and first and second substantially parallel side edges, with the first side edge extending from the first end, and the second side edge extending from the second end, wherein the optic module is receivable within the receptacle with the front edge oriented toward an interior end of the receptacle.

[0010] In some embodiments, the thermally conductive interface is spaced from the edge by at least 0.2 cm. In some embodiments, the thermally conductive interface is spaced from the edge by between 0.5 - 1 cm.

[0011] In some embodiments, the thermally conductive interface is spaced from the front edge by between 0.5 - 1 cm. In some embodiments, the thermally conductive interface is spaced from the first and second side edges by between 0.5 - 1 cm.

[0012] In some embodiments, the thermally conductive interface exhibits a thermal conductivity of at least 5 W / m*K.

[0013] In some embodiments, the thermally conductive interface has a thickness of between 0.1 and 0.5 mm.

[0014] A system for thermal control of an optic module having a heat-dissipating surface bound by an edge, wherein the system includes a thermally conductive interface including a polymer matrix and thermally conductive particulate filler dispersed in the polymer matrix, the thermally conductive interface being disposed at the heat2024P00344dissipating surface of the optic module, and spaced from the edge by at least 0.2 cm. The system further includes a frame having a heat sinking surface and a receptacle that is configured to removably receive the optic module therein with the thermally conductive interface in contact with the heat sinking surface.

[0015] In some embodiments, the edge incudes a front edge extending between a first end and a second end, and first and second substantially parallel side edges, with the first side edge extending from the first end, and the second side edge extending from the second end, wherein the optic module is receivable within the receptacle with the front edge oriented toward an interior end of the receptacle.

[0016] In some embodiments, the optic module is receivable with slidable contact between the thermally conductive interface and the heat sinking surface.

[0017] In some embodiments, the thermally conductive interface is spaced from the edge by between 0.5 - 1 cm. In some embodiments, the thermally conductive interface is spaced from the front edge by between 0.5 - 1 cm. In some embodiments, the thermally conductive interface is spaced from the first and second side edges by between 0.5 - 1 cm.

[0018] In some embodiments, the thermally conductive interface has a thickness of less than 1 mm. In some embodiments, the thermally conductive interface has a thickness of between 0.1 and 0.5 mm.

[0019] In some embodiments, the thermally conductive interface exhibits a thermal conductivity of at least 10 W / m*K.

[0020] In some embodiments, the optic module is an optical transceiver.

[0021] In some embodiments, the polymer matrix is selected from a non-silicone material.BRIEF DESCRIPTION OF THE DRAWINGS

[0022] FIG. 1 is a schematic cross-sectional view of a system of the present invention, with a replaceable electronic component being installed into a receptacle of a host device.2024P00344

[0023] FIG. 2 is a schematic cross-sectional view of a system of the present invention, with the replaceable electronic component installed into the receptacle of the host device.

[0024] FIG. 3 is a schematic cross-sectional view of a thermally conductive interface usable in a system of the present invention.

[0025] FIG. 4 is a schematic top view of a replaceable electronic component usable in a system of the present invention.

[0026] FIG. 5 is a schematic illustration of a testing apparatus for testing heat transfer durability for replaceable electronic components.DETAILED DESCRIPTION

[0027] A system as described herein supports a replaceable electronic component that is adapted to interact with a host device when installed at the host device. The replaceable electronic component is installed with, and removed from, the host device, typically through a slidable engagement and disengagement with a heat sinking surface associated with the host device. The heat sinking surface is typically positioned with respect to a receptacle of the host device so that installation of the electronic component into the receptacle places the electronic component into thermal contact with the heat sinking surface. Preferably, the thermal contact is established by a thermal interface between the electronic component and the heat sinking surface. The thermal interface may preferably be an abrasion resistant and cohesive body in the form of a pad, film, or coating adhered to a heat dissipating surface of the electronic component. Installation of the replaceable electronic component into the receptacle therefore establishes a thermal dissipation pathway from the heat dissipating surface of the electronic component, through the thermal interface, to the heat sinking surface of the host system.

[0028] As used herein, “host device” and “host system” is intended to mean a computer or computing device, network device, signal transmitter, signal receiver, switch, data storage device, subsystem, or the like.

[0029] As used herein, the terms “electronic component”, “component”, and “’module” are intended to mean any device that is adapted to cooperate with the host2024P00344system to perform a function, and may include a component that processes, receives, and / or transmits signals or communication with the host system. Examples include a receiver, a transceiver, a transmitter, a switch, a chip, an integrated circuit, or the like. It is contemplated that the electronic component may generate heat in its operation.Electronic component heat sources may include, for example, a processor, memory, a power supply, a power converter, a light emitting diode, and a laser emitting diode.

[0030] FIGS. 1 and 2 depict schematic cross-sectional views of an example system 10. A replaceable module 12 is illustrated as being installable along direction arrow 13 into a receptacle 14 of host device 16. The host device 16 includes a frame 18 defining the receptacle 14 having an interior end 15. FIG. 2 illustrates system 10 with replaceable module 12 installed at receptacle 14 of frame 18. In some embodiments, replaceable module 12 is an optical module that is used in high-bandwidth data communication applications. The optical module may be replaceable, in that the module is hot-swappable with the respective data communication system. The optical module typically has an electrical interface on the side that connects to the inside of the communications system, and an optical interface on the side that communicatively connects through a fiber optic cable. Replaceable module 12 is illustrated with a communications cable 3, such as a fiber optic cable.

[0031] Replaceable module 12 may be an optical transceiver that is capable of both transmitting and receiving data, wherein system 10 is a network communications device. The optical transceiver is preferably removably pluggable into the network communications device. A variety of form factors are conventionally used for such optical transceivers, and are contemplated as being useful as replaceable module 12.

[0032] Replaceable module 12 may include a heat source 5 that generates heat during the operation of replaceable module 12. Generally, the heat source 5 is mounted to a support 4. A non-limiting example of the support 4 is a printed circuit board (PCB). In this illustration, the heat source 5 is surface mounted onto the support 4. Heat generated from the heat source 5 is radiated by one or both of conduction and convection to a heat-dissipating surface 7 of replaceable module 12. It is contemplated that heat generated by replaceable module 12 may be transferred to portions of replaceable module 12 in addition to heat-dissipating surface 7, but for the purposes of2024P00344this description, heat dissipation is directed through heat-dissipating surface 7 to frame 18 of host device 16 through a thermally conductive interface 30.

[0033] A heat sinking surface 22 is associated with frame 18 of host device 16. The heat sinking surface 22 may be a portion of frame 18, or may be of a body thermally coupled to frame 18. In some embodiments, heat sinking surface 22 is an integral feature of frame 18, constructed of highly thermally conductive materials, such as metals, metal alloys, and the like. Frame 18 may comprise a heat sink structure that includes a plate portion 23 and heat dissipation fins or pins 24 to maximize the surface area from which to dissipate heat to a cooling medium in contact with the heat dissipation fins or pins 24, such as ambient air. At least heat sinking surface 22, and preferably at least the portion of frame 18 between heat sinking surface 22 and the heat dissipation fins or pins 24 may be a highly thermally conductive material, examples of which include aluminum and copper.

[0034] A thermally conductive interface 30 is preferably disposed at the heat dissipating surface 22 of the replaceable module 12 to define a thermal dissipation pathway wherein heat from the replaceable module 12 is most efficiently transferred to heat sinking surface 22 through the thermally conductive interface 30. As shown in FIG.2, the thermally conductive interface 30 may be applied to heat-dissipating surface 7 so that the thermally conductive interface 30 is in contact with heat sinking surface 22 of frame 18 when replaceable module 12 is received in receptacle 14. Such contact facilitates efficient heat transfer from the thermally conductive interface 30 to heat dissipating surface 22.

[0035] Generally, when replaceable module 12 is installed into receptacle 14 of host device 16, the thermally conductive interface 30 is thermally coupled to heatdissipating surface 7, preferably in direct physical contact therewith. The thermally conductive interface 30 is therefore positioned at an intersection between replaceable module 12 and heat sinking surface 22 of frame 18. In this manner, replaceable module 12 can become thermally coupled to heat sinking surface 22 via the thermally conductive interface 30.

[0036] The thermally conductive interface 30 is preferably abrasion-resistant for durability in applications as described herein with replaceable module 12 being2024P00344repeatedly installed and removed from the receptacle 14 of host device 16. The replaceable module 12 is typically installed and removed with sliding physical contact between the thermally conductive interface 30 and heat sinking surface 22. Accordingly, damage to the thermally conductive interface as a result of such repeated installations and removals can significantly increase the thermal impedance at the interface between heat-dissipating surface 7 of replaceable module 12 and heat sinking surface 22.Therefore, it is important that the thermally conductive interface 30 be fabricated and arranged in a manner to limit or avoid damage as a consequence of the repeated installations and removals of replaceable module 12 during its lifetime.

[0037] The thermally conductive interface 30 is preferably formed from one or more polymer-forming resins and one or more thermally conductive particulate fillers dispersed in the polymer matrix. Polymer resin compositions may be chosen to have desired mechanical and thermal properties. Example polymer resin materials include epoxies, acrylates, and polyurethanes. A particular example polymer resin material is an acrylic rubber or acrylic resin. In some embodiments, the base material may be a mixture of components such as resin combined with a plasticizer material.

[0038] Advantageously, in some embodiments, the base material of the thermally conductive interface 30 may be free or substantially free of silicones or other siloxane-based polymers which are known to exhibit degradation, outgassing, and other undesirable properties at high temperature. For the purposes hereof, the term “nonsilicone” means a material that is free or substantially free of silicone.

[0039] The filler material may include inorganic particulate filler, and, in some embodiments, anisotropically oriented particles. The thermally conductive filler particles may be preferentially oriented along a primary direction through a thickness of the thermally conductive interface 30 to promote thermal conduction through the interface along the primary direction.

[0040] In some embodiments, the particulate filler is an inorganic filler selected from the group consisting of aluminum oxide, diamond, clay, aluminosilicate, aluminum nitride, boron nitride, aluminum oxide, aluminum nitride, magnesium oxide, zinc oxide, silicon carbide, silicon dioxide, beryllium oxide, antimony oxide, graphite, and combinations thereof. In a specific embodiment of the formulation, the inorganic2024P00344particulate filler is aluminum nitride. In another embodiment, the filler is selected from the group consisting of carbon nanotubes, graphene, fullerene, boron nitride, and graphite.

[0041] The thermally conductive interface 30 may exhibit a thermal conductivity of at least about 1 W / m*K, more preferably at least about 5 W / m*K, and more preferably at least 10 W / m*K, with the thermal conductivity measured through a thickness of the thermally conductive interface 30. In some embodiments, the thermal conductivity through the thickness is at least 20 W / m*K, 40 W / m*K, 60 W / m*K, 80 W / m*K, 100 W / m*K, or more, as measured using the ASTM standard D5470 known in the art.

[0042] An example thermally conductive interface 30 is described in U.S. Patent Nos. 11,326,843; 11,441,855; and 12,130,095, the contents of which being incorporated herein by reference in their entireties.

[0043] Referring to FIG. 3, an example thermally conducive interface 30 is shown disposed at heat-dissipating surface 7. The thermally conductive interface 30 is formed as a pad, sheet, or film 32. In the illustrated embodiment, the thermally conductive interface 30 includes a first sheet 32a extending between a first major surface 34 and a second major surface 36, and a second sheet 32b disposed at first major surface 34 of first sheet 32a and applied to heat-dissipating surface 7. The combination of the first and second sheets 32a, 32b form the pad, sheet, or film 32, with a thickness “T” measured substantially perpendicularly to second major surface 36 along a primary direction 38. The thickness dimension “T” is measured between a contact surface 33 of second sheet 32b in contact with heat-dissipating surface 7, and second major surface 36 of first sheet 32a. Although a flat pad 32 is shown, it will be apparent to one skilled in the art that other shapes may be used, such as a curved sheet, or a sheet cut to custom shape and dimensions as desirable for a given application. In some embodiments, thickness “T” may be at least 0.01 mm, at least 0.05 mm, or at least 0.1 mm. In some embodiments, thickness “T” may be between 0.01 mm and 5 mm, between 0.01 mm and 3 mm, between 0.05 and 2 mm, between 0.1 and 1 mm, or between 0.1 and 0.5 mm.

[0044] An aspect of the invention is the prevention or reduction of damaged sustained to thermally conductive interface 30 over the course of repeated installations2024P00344into and removals from receptacle 14 of host device 16. This object is particularly challenging for thermally conductive interfaces 30 having a thickness “T” of at least 0.01 mm. Typical thermal interfaces uses in optical transceivers have a thickness of less than 0.01 mm. The greater thickness of the present thermally conductive interface 30 is therefore subjected to larger abrading forces and higher risk of catching on edges of the host device 16 than conventional thermal interfaces. Accordingly, the thermally conductive interface 30 of the invention is preferably specifically adapted to limit abrading and / or disrupting forces sustained during insertion / pull cycles of the replaceable module 12 with respect to host system 16.

[0045] Applicants have surprisingly found that thermally conductive interfaces with certain compositional combinations can reduce surface friction while maintaining good thermal conductivity properties. The surface friction reduction establishes an abrasion resistance that limits damage to the thermally conductive interface when subjected to abrading forces like repeated installations into and removals from receptacle 14 of the host device 16. In some embodiments, the thermally conductive interface 30 includes a non-silicone resin matrix with thermally conductive particulate filler dispersed in the non-silicone resin matrix, wherein the thermally conducive particulate filler is selected from boron nitride, graphite, and combinations thereof. In some embodiments, one or both of the boron nitride and graphite thermally conductive particulate filler is platelet-shaped. In some embodiments, one or both of the boron nitride and graphite thermally conductive particulate filler has an aspect ratio of at least 1.5, at least 1.8, at least 2.0, or at least 2.5.

[0046] In some embodiments, first sheet 32a may include a first non-silicone resin matrix and thermally conductive particulate filler dispersed in the first non-silicone resin matrix. The first non-silicone resin matrix may include an acrylic-based polymer. The thermally conductive particulate filler may be included in the non-silicone resin matrix in an amount of at least 50 wt.% of the first sheet 32a. In some embodiments, the thermally conductive particulate filler may be included in the non-silicone resin matrix in an amount of at least 60 wt.% of the first sheet 32a. In some embodiments, the thermally conductive particulate filler may be included in the non-silicone resin matrix in an amount of at least 70 wt.% of the first sheet 32a. In some embodiments, the2024P00344thermally conductive particulate filler may be included in the non-silicone resin matrix in an amount of at least 80 wt.% of the first sheet 32a. In some embodiments, the thermally conductive particulate filler may be included in the non-silicone resin matrix in an amount of at least 90 wt.% of the first sheet 32a. In some embodiments, the thermally conductive particulate filler may be included in the non-silicone resin matrix in an amount of at least 95 wt.% of the first sheet 32a.

[0047] In some embodiments, second sheet 32b may include a second non-silicone resin matrix, wherein the second sheet is substantially free of thermally conductive particulate filler. The second non-silicone resin matrix may include an acrylicbased polymer. In some embodiments, the second non-silicone resin matrix may be selected for its compatibility with the first non-silicone resin matrix. In some embodiments, the second non-silicone resin matrix may be the same as the first non-silicone resin matrix. In some embodiments, the first resin matrix and the second resin matrix each include acrylic-based polymers. In some embodiments, the second non-silicone resin matrix may comprise an acrylic-based pressure-sensitive adhesive.

[0048] FIG. 4 is a schematic top view of the replaceable module 12, illustrating thermally conductive interface 30 disposed at heat-dissipating surface 7. Applicants have determined that specific placement of the thermally conductive interface 30 at heat dissipating-surface 7, and particularly the position of thermally conductive interface 30 relative to edge 40, significantly affects the thermal performance of thermally conductive interface 30 over it lifetime usage of repeated installations into and removals from receptacle 14 of host device 16. As described above, abrasion of the thermally conductive interface can physically damage the interface pad or film, which disrupts good thermal pathways through the interface, and results in increased thermal impedance across the interface. Applicants have discovered that a specific arrangement of a thermal interface pad or film with good adhesion to the heat-dissipating surface 7 can dramatically improve the durability of thermal transfer performance.

[0049] As illustrated in FIG. 4, the heat-dissipating surface 7 is bound by edge 40, which includes a front edge 40a that extends between a first end 42 and a second end 44. Edge 40 further includes a first side edge 40b and a second side edge 40c, wherein the first side edge 40b extends from the first end 42 away from front edge 40a,2024P00344and the second side edge 40c extends from the second end 44 away from front edge 40b. In the illustrated embodiment, first and second side edges 40b, 40c extend from respective first and second ends 42, 44 substantially in parallel. The replaceable module 12 is receivable within receptacle 14 of host device 16 with the front edge 40a oriented

[0050] Thermally conductive interface 30 is preferably disposed at heatdissipating surface 7 of replaceable module 12 in a position that is spaced from the edge 40. For the purposes hereof, being “spaced from the edge” is intended to mean that a boundary zone 46 is established between the edge 40 and the thermally conductive interface 30. In some embodiments, the boundary zone 46 is only heatdissipating surface 7 between the edge 40 and the thermally conductive interface 30. In some embodiments, heat-dissipating surface 7 at the boundary zone 46 is substantially planar, extending along a plane from the edge 40 and along contact surface 33 of thermally conductive interface 30. Heat-dissipating surface 7 may extend along the plane in juxtaposition with the contact surface 33 throughout an entire surface area of contact surface 33.

[0051] It has been found that a particular spacing from the edge 40 provides the benefit of substantially reducing degradation of the thermally conductive interface 30 during repeated insertion / pull cycles of the replaceable module 12 in receptacle 14 of host device 16. Such spacing minimizes abrasion damage inflicted upon the thermally conductive interface 30 during installation of the replaceable module 12 into and removal from receptacle 14, while maintaining good heat dissipation from heatdissipating surface 7. In that respect, the spacing dimensions described herein are considered to be critical to the successful operation of the thermally conductive interface 30. If the spacing is too small, the thermally conductive interface is damaged during the insertion / pull cycles of the replaceable module 12 in receptacle 14, thereby leading to substantially increased thermal impedance across the thermally conductive interface. If the spacing is too large, then the capacity for thermal transmission through the interface is diminished because too much area of heat-dissipating surface 7 is not covered by the thermally conductive interface 30. In some embodiments, therefore, thermally conductive interface 30 may be disposed at heat-dissipating surface 7 of replaceable2024P00344module 12 in a position that is spaced from the edge 40 by at least 0.2 cm. In some embodiments, thermally conductive interface 30 is spaced from the edge 40 by at least 0.3 cm. In some embodiments, thermally conductive interface 30 is spaced from the edge 40 by at least 0.4 cm. In some embodiments, thermally conductive interface 30 is spaced from the edge by at least 0.5 cm. In some embodiments, the thermally conductive interface 30 is spaced from the edge by between 0.5 - 1 cm.

[0052] The thermally conductive interface 30 may be spaced from the front edge 40a by at least 0.2 cm to define a front boundary zone 46a having a dimension “Si” of at least 0.2 cm. The front boundary zone 46a is defined between the front edge 40a, the first side edge 40b, the second side edge 40c, and the thermally conductive interface 30. In some embodiments the thermally conductive interface 30 may be spaced from the front edge 40a by at least 0.3 cm to define a front boundary zone 46a having a dimension “Si” of at least 0.3cm. In some embodiments, the thermally conductive interface 30 may be spaced from the front edge 40a by at least 0.4 cm to define a front boundary zone 46a having a dimension “Si” of at least 0.4 cm. In some embodiments, the thermally conductive interface 30 may be spaced from the front edge 40a by at least 0.5 cm to define a front boundary zone 46a having a dimension “Si” of at least 0.5 cm. In some embodiments, the thermally conductive interface 30 may be spaced from the front edge 40a by between 0.5 - 1 cm to define a front boundary zone 46a having a dimension “Si” of between 0.5 - 1 cm.

[0053] The thermally conductive interface 30 may be spaced from the first side edge 40b by at least 0.2 cm to define a first side boundary zone 46b having a dimension “S2” of at least 0.2 cm. The first side boundary zone 46b is defined between the front edge 40a, the first side edge 40b, a rear delineation line 40d, and the thermally conductive interface 30. In some embodiments the thermally conductive interface 30 may be spaced from the first side edge 40b by at least 0.3 cm to define a first side boundary zone 46b having a dimension “S2” of at least 0.3cm. In some embodiments, the thermally conductive interface 30 may be spaced from the first side edge 40b by at least 0.4 cm to define a first side boundary zone 46b having a dimension “S2” of at least 0.4 cm. In some embodiments, the thermally conductive interface 30 may be spaced from the first side edge 40b by at least 0.5 cm to define a first side boundary zone 46b2024P00344having a dimension “S2” of at least 0.5 cm. In some embodiments, the thermally conductive interface 30 may be spaced from the first side edge 40b by between 0.5 - 1 cm to define a first side boundary zone 46b having a dimension “S2” of between 0.5 - 1 cm.

[0054] The thermally conductive interface 30 may be spaced from the second side edge 40c by at least 0.2 cm to define a second side boundary zone 46c having a dimension “S3” of at least 0.2 cm. The second side boundary zone 46c is defined between the front edge 40a, the second side edge 40c, a rear delineation line 40d, and the thermally conductive interface 30. In some embodiments, the thermally conductive interface 30 may be spaced from the second side edge 40c by at least 0.3 cm to define a second side edge boundary zone 46c having a dimension “S3” of at least 0.3 cm. In some embodiments, the thermally conductive interface 30 may be spaced from the second side edge 40c by at least 0.4 cm to define a second side boundary zone 46c having a dimension “S3” of at least 0.4 cm. In some embodiments, the thermally conductive interface 30 may be spaced from the second side edge 40c by at least 0.5 cm to define a second side boundary zone 46c having a dimension “S3” of at least 0.5 cm. In some embodiments, the thermally conductive interface 30 may be spaced from the second side edge 40c by between 0.5 - 1 cm to define a second side boundary zone 46c having a dimension “S3” of between 0.5 - 1 cm.

[0055] The thermally conductive interface 30 may be spaced from each of the front edge 40a, and the first and second side edges 40b, 40c by at least 0.2 cm, 0.3 cm, 0.4 cm, or 0.5 cm. In some embodiments, the thermally conductive interface 30 may be spaced from each of the front edge 40a, and the first and second side edges by between 0.5 - 1 cm.Thermal Performance Testing

[0056] Abrasion resistance and durability of the thermally conductive interface 30 in the arrangement of the present invention were tested through a thermal performance, comparing thermal impedance (°C / W) before and after a series of insertion / pull cycles of the replaceable module 12 in a receptacle 14 or a host device 16. The test apparatus used the body of a QSFP-DD optical transceiver from FS, Inc. and a compatible cage2024P00344forming a receptacle mimicking a receptacle of a data communications switch. A cooling fan was operated at a speed of 5 ft3 / min to direct a moving air stream over the cooling fins associated with the cage. As illustrated in the schematic FIG. 5, to the undersurface 8 of the optical transceiver body 12 was secured a first Watlow Ultramic Heater, CER-1-01-00334, (“HEATER 1”), having a power of 12.2W, and a second Watlow Ultramic Heater, CER-1 -01 -00334, (“HEATER 2”), having a power of 7.8W, for a total output of 20W. Each of the heaters were secured to the undersurface 8 with Loctite® Ablestik 2902, cured for 2 hours at 65 °C. Each of the heaters contained thermocouples to measure the temperature at the undersurface 8, which is considered to be the same temperature as that of heat-dissipating surface 7 because undersurface 8 and heatdissipating surface 7 are opposed surfaces of a steel sheet forming the top of the optical transceiver body.

[0057] A Control Sample was provided without a thermally conductive interface pad or film at heat-dissipating surface 7 of the test apparatus. Test Sample 1 was prepared by applying a first thermally conductive interface (“TIM 1”) to the heatdissipating surface 7 of the test apparatus, spaced from each of the front edge and first and second side edges by 0.5 cm. TIM 1 had a thickness of 0.3 mm. Test Sample 2 was prepared by applying a second thermally conductive interface (“TIM 2”) to the heatdissipating surface 7 of the test apparatus, spaced from each of the front edge and first and second side edges by 0.5 cm. TIM 2 had a thickness of 0.3 mm.TIM 1 Composition

[0058] The thermally conductive interface of TIM 1 was formed as a two-layer or two-sheet acrylic pad. The first layer / sheet was a Henkel TGP 40000SF silicone-free Gap Pad, and the second layer / sheet of TIM 1 comprised the UV-curable acrylic polymer resin used in the first layer / sheet, without particulate filler. The second layer / sheet was applied to a thickness of between 1-10 pm.

[0059] The TIM 1 was applied with the second layer / sheet in contact with the heat dissipating surface of the test apparatus.2024P00344TIM 2 Composition

[0060] The thermally conductive interface of TIM 2 was formed as a two-layer or two-sheet acrylic pad. The first layer / sheet was a Henkel TGP 18000SF silicone-free Gap Pad, and the second layer / sheet of TIM 2 comprised the UV-curable acrylic polymer resin used in the first layer / sheet, without particulate filler.

[0061] The second layer / sheet was applied to a thickness of between 1-10 pm.

[0062] The TIM 2 was applied with the second layer / sheet in contact with the heat dissipating surface of the test apparatus.Test Procedure

[0063] Heaters 1 and 2 were energized to their operating power, and the thermocouples measured the temperature after 7 minutes. Measurements were taken at 0 insertion / pull (IP), and after trials of 10 IP, 20 IP, 50 IP, and 100 IP. The term “insertion / pull” means a single cycle of: a full insertion of the test optical transceiver into the receptacle of the cage; and a full removal of the test optical transceiver from the receptacle of the cage. For example, “10 IP” means a trial of ten consecutive insertion / pulls.EXAMPLES

[0064] The following samples were tested for thermal performance. The values given in the tables are the readings from the heater thermocouples, as well as a calculated thermal impedance.EXAMPLE 1

[0065] The test apparatus with TIM 1 provided superior thermal conductivity to the Control sample that relied on metal-to-metal contact between the heat dissipating surface of the replaceable module and the heat sinking surface of the host device. The2024P00344thermally conductive interface of TIM 1 resulted in a 10.8 °C and 7.3 °C reduction of temperature at the thermocouples.EXAMPLE 2

[0066] The test apparatus with TIM 2 provided superior thermal conductivity to the Control sample that relied on metal-to-metal contact between the heat dissipating surface of the replaceable module and the heat sinking surface of the host device. The thermally conductive interface of TIM 2 resulted in a 12.8 °C and 8.7 °C reduction of temperature at the thermocouples.EXAMPLE 3

[0067] The test apparatus with TIM 2 provided superior thermal conductivity to the Control sample that relied on metal-to-metal contact between the heat dissipating surface of the replaceable module and the heat sinking surface of the host device. The test apparatus with TIM 2 also demonstrated stable thermal performance over the course of up to 100 IP. Only slight performance degradation was noted over 100 IP.2024P00344EXAMPLE 4

[0068] The test apparatus with TIM 1 provided superior thermal conductivity to the Control sample that relied on metal-to-metal contact between the heat dissipating surface of the replaceable module and the heat sinking surface of the host device. The test apparatus with TIM 1 also demonstrated stable thermal performance over the course of up to 100 IP.Abrasion Resistance Testing

[0069] Abrasion resistance of the thermally conductive interface 30 in the arrangement of the present invention was tested through a peel force study, comparing peel force (g) of various compositions for a thermally conductive interface. Samples were tested on an Imass SP-2100 peel tester set to a 5kg cell at a test speed of 12 inches / min. Comparative samples were prepared, with comparison sample 1 (Comp 1) being a Henkel TGP HC5000 fiber-reinforced silicone pad, comparison sample 2 (Comp 2) being a Henkel TGP 10000ULM silicone pad, and comparison sample 3 (Comp 3) being a Henkel microTIM 1028 silicone pad. The table below captures peel force of each of the five samples.2024P00344

[0070] The peel testing clearly demonstrated that the thermally conductive interface compositions of TIM 1 and TIM 2, incorporating non-silicone resin matrices with boron nitride and / or graphite particulate filler, exhibit substantially lower peel force than the silicone-based, alumina-filled counterparts represented by Comp 1, Comp 2, and Comp 3.

Claims

2024P00344What is claimed is:

1. A system for thermal control of an optical module having a heat-dissipating surface bound by an edge, the system comprising:a thermally conductive interface comprising:a first sheet extending between a first major surface and a second major surface, the first sheet comprising a first non-silicone resin matrix and thermally conductive particulate filler dispersed in the first non-silicone resin matrix, the thermally conductive particulate filler comprising at least 50 wt.% of the first sheet; anda second sheet disposed at the first major surface of the first sheet, the second sheet comprising a second non-silicone resin matrix, wherein the second sheet is substantially free of thermally conductive particulate filler, whereinthe thermally conductive interface is disposed at the heat-dissipating surface of the optical module, and has a thickness of between 0.01 and 3 mm; anda frame having a heat sink surface and a receptacle that is configured to removably receive the optical module therein with the thermally conductive interface in contact with the heat sink surface.

2. The system as in Claim 1 wherein the first resin matrix and the second resin matrix each include acrylic-based polymers, and the thermally conductive particulate filler is selected from at least one of boron nitride and graphite.

3. The system as in Claim 1 wherein the edge includes a front edge extending between a first end and a second end, and first and second substantially parallel side edges, with the first side edge extending from the first end, and the second side edge extending from the second end, wherein the optical module is receivable within the receptacle with the front edge oriented toward an interior end of the receptacle.

4. The system as in Claim 3 wherein the thermally conductive interface is spaced from the edge by at least 0.2 cm.

5. The system as in Claim 4 wherein the thermally conductive interface is spaced from the edge by between 0.5 - 1 cm.

6. The system as in Claim 5 wherein the thermally conductive interface is spaced from the front edge by between 0.5 - 1 cm.2024P003447. The system as in Claim 6 wherein the thermally conductive interface is spaced from the first and second side edges by between 0.5 - 1 cm.

8. The system as in Claim 1 wherein the thermally conductive interface exhibits a thermal conductivity of at least 5 W / m*K.

9. The system as in Claim 1 wherein the thermally conductive interface has a thickness of between 0.1 and 0.5 mm.

10. A system for thermal control of an optical module having a heat-dissipating surface bound by an edge, the system comprising:a thermally conductive interface comprising a polymer matrix and thermally conductive particulate filler dispersed in the polymer matrix, the thermally conductive interface being disposed at the heat-dissipating surface of the optical module, and spaced from the edge by at least 0.2 cm; anda frame having a heat sinking surface and a receptacle that is configured to removably receive the optical module therein with the thermally conductive interface in contact with the heat sinking surface.

11. The system as in Claim 10 wherein the edge includes a front edge extending between a first end and a second end, and first and second substantially parallel side edges, with the first side edge extending from the first end, and the second side edge extending from the second end, wherein the optical module is receivable within the receptacle with the front edge oriented toward an interior end of the receptacle.

12. The system as in Claim 11 wherein the optical module is receivable in the receptacle with slidable contact between the thermally conductive interface and the heat sinking surface.

13. The system as in Claim 12 wherein the thermally conductive interface is spaced from the edge by between 0.5 - 1 cm.

14. The system as in Claim 13 wherein the thermally conductive interface is spaced from the front edge by between 0.5 - 1 cm.

15. The system as in Claim 14 wherein the thermally conductive interface is spaced from the first and second side edges by between 0.5 - 1 cm.

16. The system as in Claim 10 wherein the thermally conductive interface has a thickness of at least 0.1 mm.2024P0034417. The system as in Claim 16 wherein the thermally conductive interface has a thickness of between 0.1 and 0.5 mm.

18. The system as in Claim 17 wherein the thermally conductive interface exhibits a thermal conductivity of at least 10 W / m*K.

19. The system as in Claim 18 wherein the optical module is an optical transceiver.

20. The system as in Claim 10 wherein the polymer matrix is selected from a nonsilicone material.

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