The present invention relates to thermal management. More specifically, the present invention relates to thermal management of connectors, including, for example, electrical connectors and modular optical connectors such as optical couplers and optical transceivers, using metamaterials.
A connector's temperature must be controlled to ensure that the connector functions correctly. This is true if the connector is, for example, an electrical connector or an optical module such as an optical coupler or an optical transceiver, and can be achieved using proper thermal management. For example, in some applications with no forced air, a power connector's temperature should be controlled to less than about 30° C. above ambient temperature.
A terminal and a socket of a power connector can be used to transmit power. The terminal is located on a first substrate, and a socket is located on a second substrate. The terminal and the socket of the power connector can be mated together to transmit power between the first and second substrates. The socket includes socket contacts within an insulating housing, and the terminal includes terminal contacts with an insulating housing. When the socket and terminals are mated, corresponding socket contacts and terminal contacts are engaged with each to allow power to be transmitted between the first and second substrates.
Resistive heat is generated when electrical power is transmitted through the terminal and a socket of a connector system. This heat can lead to increasing temperatures. If the temperature of the connectors increases beyond a limit, then the connector system can malfunction or become degraded.
To overcome the problems described above, preferred embodiments of the present invention use metamaterials to provide better thermal management in connectors, including, for example, electrical connectors or an optical module such as an optical coupler and an optical transceiver.
According to a preferred embodiment of the present invention, an electrical connector can include an electrically insulated housing, an electrically conductive contact included in the electrically insulating housing, and metamaterial thermally connected to one of the electrically insulating housing or the electrically conductive contact. The metamaterial thermally cools the electrical connector or the contact.
According to a preferred embodiment of the present invention, an electrical connector can include an electrically insulated housing, an electrically conductive contact carried by the electrically insulating housing, an electrically conductive shield, and metamaterial thermally connected to one of the electrically insulating housing or the electrically conductive contact or the electrically conductive shield. The metamaterial thermally cools the electrical connector or the contact.
The metamaterial preferably reduces unwanted heat by approximately 5° C.-10° C. The metamaterial preferably reduces unwanted heat by approximately 5° C.-10° C. when the electrical connector is exposed to an air velocity of 200-800 feet/minute. The metamaterial preferably reduces unwanted heat by approximately 5° C.-15° C. at 3.5 Watts, approximately 5° C.-15° C. at 7 Watts, and approximately 7° C.-15° C. at 12 Watts.
Preferably, the electrical connector is cooler with respect to an identical electrical connector devoid of the metamaterial when operated at the same current and/or power, and ambient temperature. A thermal interface material is preferably directly adjacent to at least one surface of the metamaterial. The metamaterial preferably includes an array of surface holes.
According to a preferred embodiment of the present invention, a connector can include a thermal metamaterial. The thermal metamaterial provides heat flow paths from inside the connector to outside of the connector or converts heat into radiation.
Preferably, the connector is an electrical connector, a power connector, or an optical module. The thermal metamaterial preferably includes an anisotropic composite in which high thermal conductivity fibers or asymmetric particles are included in a low thermal conductivity matrix to provide the heat flow paths. The thermal metamaterial preferably converts heat into resin-transparent radiation, i.e., radiation that is not absorbed by resin and does not heat the resin. A thermal interface material is preferably directly adjacent to at least one surface of the thermal metamaterial. The thermal metamaterial preferably includes an array of surface holes.
According to a preferred embodiment of the present invention, a cage assembly can include a cage that receives a transceiver, a heatsink connected to the cage, and metamaterial thermally connected to one of the cage or the heatsink. The metamaterial thermally cools the transceiver when the transceiver is plugged into the cage.
A thermal interface material is preferably directly adjacent to at least one surface of the metamaterial. The metamaterial preferably includes an array of surface holes.
According to a preferred embodiment of the present invention, a transceiver assembly can include the cage assembly and a transceiver plugged into the cage.
Preferably, the transceiver includes a vertical-cavity surface-emitting laser (VCSEL), and the metamaterial maintains a temperature of the VCSEL between approximately −40° C. and 125° C. The metamaterial preferably includes an array of surface holes.
According to a preferred embodiment of the present invention, a connector includes a housing, an electrical contact in the housing, and a metamaterial thermally connected to the electrical contact.
The connector preferably includes a thermal interface material located between the electrical contact and the metamaterial, a thermal interface material located between the housing and the metamaterial, or both a first thermal interface material located between the electrical contact and the metamaterial and a second thermal interface material located between the housing and the metamaterial. The metamaterial preferably includes an array of surface holes.
The above and other features, elements, characteristics, steps, and advantages of the present invention will become more apparent from the following detailed description of preferred embodiments of the present invention with reference to the attached drawings.
A metamaterial includes any material engineered to produce properties that do not occur naturally. Metamaterials are discussed in U.S. Patent Application Publication No. 2017/0237300; Dede et al., “Thermal Metamaterials for Heat Flow Control in Electronics,” Journal of Electronic Packaging, vol. 140, March 2018, pp. 010904-1 to 010904-10; and Biehs et al., “Nanoscale radiative heat transfer and its applications,” Infrared Radiation, InTech, Feb. 10, 2012, 27 pages. The entire contents of these three references are hereby incorporated by reference in their entirety for all purposes, as if fully set forth herein. Metamaterials can be made from assemblies of multiple elements fashioned from composite materials such as metals or plastics and can derive their properties not from the properties of the base materials, but from their structures. Metamaterials can include composite media with nanoscale features, patterns, or elements.
Some thermal metamaterials include structures that can manipulate heat flux. For example, thermal metamaterials can include an anisotropic composite that provides heat flow control by including thermally conductive paths in a heterogeneous material by orienting high thermal conductivity fibers or asymmetric particles in a preferred direction within a low thermal conductivity matrix. In such thermal metamaterials, heat tends to flow parallel to the axis of the fiber or particle, while heat flow normal to the axis of the fiber or particle is substantially reduced. For example, Al-based thermal metamaterials could be used as the metamaterial.
Some thermal metamaterials use a three-dimensional structure to convert thermal energy into radiation. Such thermal metamaterials do not rely on convection and conduction to provide thermal management. For example, nanoscale tungsten and hafnium oxide layers in a metamaterial can suppress the emission of one portion of the electromagnetic spectrum while enhancing emission in another portion of the electromagnetic spectrum. But, other materials and structures can also be used. For example, it is also possible to use a metamaterial with an array of surface holes. The dimensions and arrangement of the surface holes can be used to tune which electromagnetic emissions are suppressed and which electromagnetic emissions are enhanced. The surface holes can act as resonators such that changing the dimensions and arrangement of the surface holes changes the resonances of the holes. The converted radiation can be infrared radiation in a controlled spectrum and can be transparent to most resins. For example, the metamaterial can transmit infrared radiation that is transmitted through and that is not absorbed by the structure to which it is attached. Therefore, a housing or other resin-containing or glass-containing component of a connector are not heated by the radiation or are not substantially heated by the radiation in comparison to an identical connector without metamaterials that uses conduction and/or convection for thermal management.
Thermal metamaterials can be used to direct heat flux of a connector to improve the thermal properties of the connector. Adding thermal metamaterial to an existing connector can help cool the connector so that more current and/or power can be transmitted through the connector before a damaging heat level is reached. Discussed below is an example of a power connector that includes a terminal and a socket as shown in
The legs 120 can be engaged with through holes in a substrate (not shown), which is typically a printed circuit board (PCB) but could be any suitable substrate.
The legs 420 can be engaged with through holes in a substrate (not shown), which is typically a printed circuit board (PCB) but could be any suitable substrate.
Metamaterials can be added to the contacts of the power connector to improve the thermal properties of the power connector. The metamaterials can be applied to any surface of the contacts. As shown in
Any arrangement of metamaterials can be used, and it is possible that different metamaterials can be used in different locations of the terminal contact, the socket contact, and the insulating housing. When determining the location and selection of the metamaterials, the heat flow paths provided by the metamaterials can be considered. If the metamaterials convert heat into radiation, then the metamaterials can be placed such that emitted radiation is not re-absorbed by a nearby metamaterial or other connector structure. For example, the metamaterials 490 can be placed on the outside surfaces of the contacts, as shown in
The metamaterials can be applied in any suitable manner. For example, some metamaterials have a back coated with an adhesive, including, for example, a pressure-sensitive adhesive, that allows the metamaterials to be directly applied to the contacts. The metamaterials can be placed to provide thermally conductive paths so that heat can flow more easily from within the insulating housing to outside of the insulating housing, which improves the thermal properties of the power connector. Such an arrangement of metamaterials on the contacts of the power connector allow more current and/or power to be transmitted before reaching the 30° C. above ambient temperature level.
The metamaterial can reduce unwanted heat in an electrical connector by approximately 5° C.-15° C. at 3.5 Watts, approximately 5° C.-15° C. at 7 Watts, approximately 7° C.-15° C. at 12 Watts, or 5° C.-10° C., such as at a 30° C. temperature rise time, compared to an identical electrical connector without metamaterials. As shown in
As mentioned above, optical modules also generate heat that can be managed with metamaterials.
For example, metamaterials can be applied to the metal housing or shield of an optical module to direct heat away from the VCSEL and/or other temperature sensitive devices. The metal housing or shield of the optical module or transceiver can include an integrally formed heat sink that defined fins. In some applications, an optical transceiver is plugged into a metal cage on a substrate. In this case, metamaterials can be applied to the metal cage. Some metal cages can include a heatsink that is in contact with the optical transceiver. Metamaterials can be applied to the heatsink such that the metamaterials are located between the heatsink and the optical transceiver to assist heat transfer. It is also possible to apply metamaterials to a hole in the cage or to make the cage out of metamaterials so that the cage functions as a heatsink. It is also possible to make the heatsink out of metamaterials. In this way, the size of a heat sink can be reduced or the need for a heat sink can be eliminated.
A method to reduce heat in a heated element 10 can include a step of placing a metamaterial 12 on, adjacent to, or in a heat path created by the heated element 10. The method can further include a step of placing the metamaterial 12 on, adjacent to, or in a heat path created by the heated element such that the metamaterial 12 is not exposed to an outside environment, such as moving gas or air. The metamaterial can be only a single planar-shaped panel, any panel devoid of heat dissipating fins or studs, or any metamaterial that does not contain thermoplastic.
The surface holes can be made by using any suitable method, including reactive ion etching (RIE), photolithography, focused ion beam (FIB) processing, nanoimprinting process using molds, anisotropic anodic etching, etc.
It should be understood that the foregoing description is only illustrative of the present invention. Various alternatives and modifications can be devised by those skilled in the art without departing from the present invention. Accordingly, the present invention is intended to embrace all such alternatives, modifications, and variances that fall within the scope of the appended claims.
This application claims the benefit of U.S. Provisional Patent Application Nos. 62/668,663, filed May 8, 2018, and 62/669,832, filed May 10, 2018; which are all hereby incorporated by reference for all purposes as if fully set forth herein.
Filing Document | Filing Date | Country | Kind |
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PCT/US2019/070005 | 5/8/2019 | WO | 00 |
Number | Date | Country | |
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62668663 | May 2018 | US | |
62669832 | May 2018 | US |