Using a conductive sheet that includes graphene for thermal conductivity and for grounding

In some examples, a computing device may include a set of components (e.g., processor, memory, and the like) and a conductive sheet (or cable). The conductive sheet (or cable) may include a first graphene layer to dissipate at least a portion of heat generated by a component (e.g., the processor) of the first set of components and a second graphene layer that is used as an electrical ground by signals communicated between a first component and a second component of the set of components. The computing device may include a single housing or a first housing (with a first display device) attached to a second housing (with a second display device) by one or more hinges.

BACKGROUND OF THE INVENTION

Field of the Invention

This invention relates generally to computing devices and, more particularly, to using one or more graphene sheets in the computing device to provide both thermal conductivity (e.g., dissipating heat by transferring the heat from heat generating components) and a ground. For example, graphene, when purified an appropriate amount or doped with other materials, may provide superior conductivity to metals commonly used for a ground, such as copper alloy, steel alloy, or other metal alloys.

Description of the Related Art

While the form factor of computing devices, such as laptops, tablets, and phones, continues to get smaller (including thinner), the thermal characteristics (e.g., heat generation) of central processing units (CPUs) remains about the same. Thermal solutions to dissipate heat generated by components, such as the CPU, while maintaining or reducing the form factor may be difficult to achieve, particular as consumers and enterprises demand greater CPU performance (e.g., faster clock speed, more processing cores, and the like), which typically causes more heat to be generated. In addition, modern computing devices may use an architecture in which the majority of the heat-generating components (e.g., CPU, graphics processing unit (GPU), memory, solid state drive (SSD), and the like) are located in a small area relative to the size of the computing devices. Without a thermal solution that can (1) dissipate thermal energy while keeping the chassis of the computing device cool and (2) prevent CPU performance from being throttled, the size (including thickness) of the computing device may remain relatively large (e.g., thick), unsuitable for modern applications, and uncompetitive in the marketplace.

SUMMARY OF THE INVENTION

This Summary provides a simplified form of concepts that are further described below in the Detailed Description. This Summary is not intended to identify key or essential features and should therefore not be used for determining or limiting the scope of the claimed subject matter.

In some examples, a computing device may include a set of components (e.g., processor, memory, and the like) and a conductive sheet (or cable). The conductive sheet (or cable) may include a first graphene layer to dissipate at least a portion of heat generated by a component (e.g., the processor) of the first set of components and a second graphene layer that is used as an electrical ground by signals communicated between a first component and a second component of the set of components. The computing device may include a single housing or a first housing (with a first display device) attached to a second housing (with a second display device) by one or more hinges.

DETAILED DESCRIPTION

The systems and techniques described herein use a conductive sheet (or cable) that is both thermally conductive and electrically conductive. By using the conductive sheet (or cable), two separate layers, e.g., a heat dissipation layer and a ground layer, can be combined, thereby enabling the thickness of the computing device to be reduced. For example, a computing device may use passive cooling, e.g., a fan may not be used to force air onto components for cooling. The advantage of passive cooling (as compared to using a fan) is that the amount of noise generated may be lower and heated air may not exit the computing device. The thermally conductivity may be used to dissipate heat caused by heat-generating components in a computing device. For example, the heat-generating components may be located in one portion of the computing device and the conductive sheet (or cable) may transfer the heat to another (e.g., cooler) portion of the computing device where the heat can be dissipated. The electrical conductivity may be used to provide an electrical ground for signals (e.g., data signals, power signals, and the like) being transmitted between components of the computing device. The conductive sheet (or cable) may be used in laptops, phones, tablets, desktop, 2-in-1 (e.g., a tablet head that can be attached to or detached from a base), or other types of computing device to provide both thermal conductivity and an electrical ground.

The conductive sheet (or cable) may be used in a computing device with two housings that are coupled to each other by a hinge. One of the housings may include computing components (e.g., typically found on a motherboard), such as central processing unit (CPU), a graphics processing (GPU), memory, and the like.

One or more of the components housed in the computing device may be in contact with a vapor chamber. A vapor chamber is a hollow cylinder (or other sealed shape) that includes a small amount of a liquid in a vacuum. The vapor chamber may be made using a metal alloy, such as copper alloy. When heat is present at one end of the vapor chamber, the heat may cause the liquid to vaporize. The vaporized liquid may condense back to a liquid at another (e.g., cooler) end of the vapor chamber. The vapor chamber may be used to cool one or more components, such as, for example, the CPU, the GPU, the memory devices, and the like.

The conductive sheet (or cable) may be in contact with the vapor chamber that is located in a first portion of the computing device that houses heat-generating components (e.g., CPU, GPU, memory, or the like). The conductive sheet may conduct heat from the first set of components (e.g., via the contact with the vapor chamber) to a second portion of the computing device where the heat is more easily dissipated (e.g., because a second set of components housed in the second portion generates less heat than the first set of components).

The conductive sheet (or cable) may include one or more layers of thermally conductive materials, such as graphite, copper, aluminum, another type of material, or any combination thereof. In some cases, such as when the computing device includes a first housing connected to a second housing by one or more hinges, the conductive sheet (or cable) may include three portions, e.g., a first portion in the first housing, a second portion in the second housing, and a third portion that thermally connects the first portion to the second portion. The third portion of the conductive sheet may be sufficient flexible to enable the first housing to be placed at an angle (e.g., preferably between about 0 to about 180 degrees or between about 0 to about 360 degrees) relative to the second housing. The third portion of the conductive sheet may be capable of thermally conducting heat from a warmer housing to a cooler housing while the first housing is placed at an angle relative to the second housing. In addition, the third portion of the conductive sheet may be designed to be repeatedly flexed (e.g., articulated) without breaking (or other damage) for an expected life of the computing device. In some cases, the third portion of the conductive sheet may be placed inside the one or more hinges that are used to couple the first housing to the second housing of the computing device. For example, by using a conductive sheet made of graphene, a flexible material, the conductive sheet can be used for both housings by threading the conductive sheet through hollowed out hinges. In some cases, a portion of the conductive sheet may protrude outside the first housing and the second housing around the hinge area. In such cases, the exposed conductive sheet may be protected using a cover made out of leather, plastic, cloth, or other flexible material with insulating properties.

By using a conductive sheet, the temperature difference between two portions (or two housings) of the computing device may be reduced to less than a pre-determined threshold (e.g., preferably less than 6 degrees Fahrenheit and more preferably less than 4 degrees Fahrenheit). For example, the temperature difference between two different portions of the computing device may be reduced to a level that does not cause users to become concerned. Furthermore, a conductive sheet that spans both housings of a computing device may distribute the thermal load across both sides (e.g., housings), approximately doubling the surface area used for thermal dissipation. By increasing thermal dissipation using a conductive sheet, components that use more power may be used in the design of the computing device. The increased thermal dissipation may enable the computing device to support computational components that consume more power (e.g., thereby generating more heat), such as a CPU with more cores, a CPU with a faster clock speed, a more powerful (e.g., more pipelines, faster clock speed, or the like) GPU, more memory, a faster memory, or any combination thereof.

The conductive sheet includes one or more graphene layers to enable the conductive sheet to be used for cooling (e.g., thermal dissipation) and an electrical ground (e.g., signaling ground reference). For example, the conductive sheet may include a conductive layer (e.g., a metal alloy, such as copper alloy) that is “sandwiched” between two layers of graphene. The graphene layers may be used as (i) a continuous reference plane for signal integrity and (ii) ground coupling for noise suppression. The graphene reference planes may be in contact with a thermal solution (e.g., vapor chamber) on either side to enable heat transfer between the two ends of the sheet.

Thus, a conductive sheet (or cable) having at least one graphene layer may be placed in a computing device. For example, the conductive sheet (or cable) may be placed in a first housing, a second housing, and across a gap between the two housings. A cover may be used to protect the portion of the conductive sheet that is exposed (e.g., across the gap between the two housings). The conductive sheet may attach to a heat dissipation device, such as a vapor chamber, that is attached to heat generating components (e.g., CPU, GPU, memory, and the like) in a first housing. The conductive sheet may draw heat from the vapor chamber in the first housing and spread and dissipate the heat at a second housing. The conductive sheet may use a flexible, thermally conductive material, such as graphene to enable the first housing to flex and be placed at different angles relative to the second housing. The conductive sheet may have electrical characteristics that enable the conductive sheet (or cable) to be used as a ground. For example, a conductive layer of the conductive sheet (or cable) may be comprised of a metal alloy (e.g., copper alloy) may be used to communicate signals while the graphene layer(s) of the conductive sheet may be used as an electrical ground for the signals. The signals may include data signals (e.g., including video data, audio data, files, and the like), power signals, and other electrical or electronic signals communicated in a computing device. Examples of how a conductive sheet (or cable) may be used in a computing device are provided below.

As a first example, a computing device may include a set of components (e.g., processor, memory, and the like) and a conductive sheet. The conductive sheet may include (i) a first graphene layer to dissipate at least a portion of heat generated by a component of the first set of components and (ii) a second graphene layer that is used as an electrical ground by signals communicated between a first component and a second component of the set of components. For example, the signals communicated between the first component and the second component may include a data signal or a power signal. The first layer of graphene may be in contact with a heat sink (e.g., a vapor chamber) attached to at least one component of the set of components. The conductive sheet may include a conductive layer to transmit the signals communicated between the first component and the second component. The conductive sheet may include one or more openings through which a cable is routed to contact one of (i) the conductive layer, (ii) the first graphene layer, or (iii) the second graphene layer. In some cases, the conductive sheet may include a routing layer through which one or more cables may be routed.

As a second example, a computing device may include a first housing coupled to a second housing by one or more hinges and a conductive sheet. The first housing may be used to house a first display device and a first set of components. A heat sink may be in contact with at least a first component of the first set of components. The second housing may include a second display device and a second set of components. The conductive sheet may include (i) a first graphene layer to dissipate at least a portion of heat generated by the first set of components and (ii) a second graphene layer that is used as an electrical ground by signals communicated between a first component of the first set of components and a second component of the second set of components. For example, the signals communicated between the first component and the second component may include a data signal, a power signal, or another type of electrical or electronic signal. The first layer of graphene may be in contact with a heat sink attached to at least one component of the first set of components. The first graphene layer, the second graphene layer, or both may be doped using at least one of potassium nitrate (KNO3), lithium (Li), or gold(III) chloride (AuCl3). The conductive sheet may include a conductive layer to transmit the signals communicated between the first component and the second component. The conductive sheet may include one or more openings through which a cable is routed to contact one of: (i) the conductive layer, (ii) the first graphene layer, or (iii) the second graphene layer. In some cases, the conductive sheet may include a routing layer through which one or more cables may be routed.

As a third example, a computing device may include a set of components (e.g., a central processing unit (CPU)) and a cable that includes (i) a conductor to communicate signals between a first component and a second component of the set of components and (ii) a graphene layer to dissipate at least a portion of heat generated by the CPU. The signals communicated between the first component and the second component may include a data signal or a power signal. In some cases, the graphene layer may, in addition to providing heat dissipation, provide an electrical ground to the signals communicated between the first component and the second component. In other cases, the cable may include a second graphene layer to electrically ground the signals communicated between the first component and the second component. The graphene layer is doped using at least one of potassium nitrate (KNO3), lithium (Li), or gold(III) chloride (AuCl3). The computing device may include a single housing or two housings in which a first housing (with a first display device) is attached to a second housing (with a second display device) by one or more binges.

FIG. 1is a block diagram of an architecture of a computing device according to some embodiments. In some implementations, the computing device100may include two (or more) housings while in other implementations the computing device100may include a single housing (e.g., a tablet form factor). As illustrated inFIG. 1, the computing device100may include a first housing102coupled to a second housing104via one or more hinges106. The hinges106may enable the two housings102,104to be positioned at different angles relative to each other in different orientations (e.g., various vertical orientations and various horizontal orientations). Of course, additional housings may be attached via additional hinges to create a computing device with multiple housings. In a single housing computing device, the hinges106may be absent and the components of the computing device100may be located in a single housing (e.g., the first housing102).

A first display device108may be located in the first housing102and, in some cases (e.g., in a dual-display device), a second display device110may be located in the second housing104. A first portion of the components of the computing device100may be located in the first housing102(e.g., behind the first display device108) while a remaining portion of the components of the computing device100may be located in the second housing104(e.g., behind the second display device110). For example, as illustrated inFIG. 1, the components located in the first housing102may include at least one central processing unit (CPU)112, a graphics process unit (GPU)114, and a memory (e.g., computer-readable media)116. The GPU114may be integrated into the CPU112or may be a separate device from the GPU114. In some cases, a computer motherboard that includes the CPU112, the memory116, and the like may be located in the first housing102.

The CPU112may communicate input/output (I/O) signals118via multiple I/O post120. The I/O ports120may include video ports (e.g., a video graphics adapter (VGA) port, a digital video interface (DVI) port, a high definition media interface (HDMI) port, a ThunderBolt® port, or the like), audio ports (e.g., microphone jack, headphone jack, and the like), data ports (e.g., universal serial bus (USB) ports compliant with USB 2.0, USB 3.0, and the like), communication ports (e.g., Ethernet and the like), another type of port, or any combination thereof. In some cases, the computing device100may include at least one digital signal processing (DSP) processor to perform audio (and video) signal processing. The GPU114may provide two or more lanes of embedded DisplayPort (eDP) output124that are sent to the first display device108in the first housing102and two or more lanes of DisplayPort (DP) output126that are sent (e.g., wirelessly or via a cable) to the second display device110in the second housing104.

A first data bus128in the first housing102and a second data bus130in the second housing104may distribute data among the various components of the computing device100. For example, the data buses128,130may distribute data from the I/O signals118, the I/O ports120, a first set of sensors146, a second set of sensors148, and additional components144. For example, the data buses128,130may distribute data by receiving data from a component of the computing device100and transmitting the data to one or more of the other components of the computing device100.

The second housing104may include a remaining portion of the components of the computing device100. In some cases, the components in the second housing104may be located behind the second display device110. In a single housing computing device, the second display device110may not be present. The second housing104may include the additional components144(e.g., keyboard, touchpad, trackball, speaker, microphone, Wi-Fi antenna, Bluetooth antenna, Zigbee Antenna, cellular antenna, and the like), the second set of sensors148, a power input150(e.g., alternating current (AC) or direct current (DC) input), a charger152, and a battery154. The battery charger152may be used as a power source to provide power instead of (or in addition to) the battery154when the battery154is depleted or inoperable. In some cases, data cables may run through the hinges106to connect the components of the computing device100located in the first housing102with the components of the computing device100located in the second housing104. In other cases, a first wireless transceiver in the first housing102and a second wireless transceiver in the second housing104may provide wireless communications between (1) the components of the computing device100located in the first housing102and (2) the components of the computing device100located in the second housing104. The first set of sensors146and the second sensors152may include one or more of a touch-screen sensor, an accelerometer, a gyroscope, an electronic compass (e-compass), a barometer, a magnetometer, a proximity sensor, a light sensor, an imaging sensor (e.g., a camera), a fingerprint sensor, a global positioning satellite (GPS) sensor, another type of sensor, or any combination thereof.

One or more of the components, such as, for example, the CPU112, the GPU114, or the memory116, may be in contact with a heat sink, such as, a vapor chamber156. The vapor chamber156is a hollow cylinder, cube, or other sealed shape that includes a small amount of a liquid in a vacuum. The vapor chamber156may be made from a metal (or a metal alloy), such as copper (or a copper alloy). When heat is present at one end of the vapor chamber156, the heat may cause the liquid to vaporize. The vaporized liquid may condense back to a liquid at another (e.g., cooler) end of the vapor chamber156. The vapor chamber156may be used to cool the CPU112when the GPU114is integrated into the CPU112. The vapor chamber156may be located in whichever of the housings102,104is used to house the components generating a relatively large amount of heat. For example, as illustrated inFIG. 1, the vapor chamber156may be housed in the first housing102to cool the CPU112and the GPU114.

A conductive sheet158may be in contact with the vapor chamber156. The conductive sheet158may conduct heat from heat generating components (e.g., one or more of CPU112, GPU114, memory116), via contact with the vapor chamber156, to the second housing104, where the heat is more easily dissipated because components (e.g., battery154) housed in the second housing104may generate less heat than the components in the first housing102. Thus, the conductive sheet158may span both the first housing102and the second housing104and may draw heat from components in one housing (e.g., the first housing102) and dissipate the heat in another housing (e.g., the second housing104).

The conductive sheet158may include one or more layers of thermally conductive materials, such as graphite, copper, aluminum, another type of material, or any combination thereof. In a dual housing computing device, the conductive sheet158may include 3 portions, e.g., a first portion in the first housing102, a second portion in the second housing104, and a third portion that thermally connects the first portion to the second portion. The third portion of the conductive sheet158may be sufficient flexible to enable the first housing102to be placed at an angle (e.g., preferably between about 0 to about 180 degrees or between about 0 to about 360 degrees) relative to the second housing104. The third portion of the conductive sheet158may be capable of thermally conducting heat from the warmer housing (e.g., the first housing102) to the cooler housing (e.g., the second housing104) while enabling the first housing102to be placed at different angles relative to the second housing104. In addition, the third portion of the conductive sheet158may be designed to be repeatedly flexed (e.g., articulated) without breaking (or other damage) for an expected life of the computing device100. In some cases, the third portion of the conductive sheet158may be placed inside the one or more hinges106when the hinges106are fairly long and cover more than 50% of the length of the computing device100. The conductive sheet158may be made of a flexible material, such as graphene, enabling a single graphene sheet to be used for both housings102,104.

In some cases, when the hinges are fairly long, the conductive sheet158may be threaded through hollow hinges106. In other cases, when the hinges are fairly small, a portion of the conductive sheet158may protrude outside the first housing102and the second housing104. In such cases, the exposed conductive sheet158(e.g., graphene sheet or other material) may be protected using a cover made out of leather, plastic, cloth, or other flexible material with insulating properties.

By using the conductive sheet158that spans both housings102,104, the temperature difference between the two housings of the computing device100may be reduced to less than a pre-determined threshold (e.g., preferably less than 6 degrees Fahrenheit and more preferably less than 4 degrees Fahrenheit). For example, the temperature difference between the two sides of the computing device100may be reduced to a level that does not cause users to become sufficiently concerned to call customer service. Furthermore, the conductive sheet158may distribute the thermal load across both housings102,104, approximately doubling the surface area available for thermal dissipation. By increasing thermal dissipation using the conductive sheet158, components that use more power may be used in the design of the computing device100. The increased thermal dissipation may enable the computing device100to support computational components that consume more power (e.g., thereby generating more heat). For example, the conductive sheet158may enable the computing device100to support the CPU112with more cores and/or a faster clock speed, a more powerful (e.g., more pipelines, faster clock speed, or the like) GPU114, more memory116, a faster memory116, or any combination thereof. In addition, the conductive sheet158may be used as an electrical ground for signals transmitted among the various components of the computing device100.

InFIG. 1, the first set of components of the computing device100shown as being located in the first housing102and the remaining set of components shown as located in the second housing104are purely for illustration purposes. Depending on the implementation, different components of the computing device100may be housed in one or both of the housings102,104. For example, when the computing device100is designed for graphics processing, the GPU114and supporting hardware (e.g., graphics support chips, graphics memory, and the like) may be housed in the second housing104. As another example, in some cases, the ports120may be located in the first housing102, in the second housing104, or split between the two housings102,104. As a further example, the battery154may include multiple power cells, with a portion of the power cells located in the first housing102and zero or more of the power cells located in the second housing104. In some cases, which components of the computing device100are located in each of the housings102,104may be determined based on the thermal characteristics of the components. For example, the components may be distributed between the housings102,104by grouping components that generate the most heat into the same housing, and using the conductive sheet158to cool that housing. In addition, while the computing device100is illustrated as having two display devices108,110, in some cases the computing device100may have a single display device, e.g., when the computing device100is configured as a tablet (e.g., all components in a single housing) or a laptop computing device (e.g., with a display in the first housing and input devices, such as a keyboard and touchpad, in the second housing).

Software instructions implementing an operating system and one or more applications, including at least one application capable of receiving stylus input, may be stored in the memory116. The software instructions may be executed by the CPU112, by the DSP processor, or any combination thereof.

Thus, a conductive sheet comprised of a single sheet may span a first housing, a second housing, and a gap between the two housings. The conductive sheet may have one or more layers of material, including an electrically and thermally conductive material, such as graphene. A cover may be used to protect the portion of the conductive sheet that is exposed (e.g., across the gap between the two housings). The conductive sheet may attach to a vapor chamber that is coupled to heat generating components (e.g., CPU, GPU, memory, and the like) in a first housing. The conductive sheet may draw heat from the vapor chamber in the first housing and dissipate the heat in a second housing. The conductive sheet may use a flexible, thermally and electrically conductive material, such as graphene, to enable the first housing to flex and be placed at different angles relative to the second housing. Of course, in a single housing computing device, the conductive sheet may be located in a single housing. The graphene layer(s) of the conductive sheet may be used as an electrical ground to enable transmitting signals (data signals, power signals, and the like) between the various components of the computing device100.

FIG. 2is a block diagram illustrating different orientations of a dual-housing computing device (e.g., the computing device100ofFIG. 1) according to some embodiments. The computing device100may include two housings102,104. One or both of the housings102,104may include a display device. In some cases, one of the housings102,104may include a display device and the other housing may include one or more input devices, such as a keyboard, trackpad, and the like.

The computing device100may be displayed in a vertical (e.g., portrait) orientation202or a horizontal (e.g., landscape) orientation204. For example, in the vertical orientation202, the first housing102may be on one side (e.g., the left side or the right side), the second housing104may be on another side (e.g., the right side or the left side), and the hinge106may join the first housing102to the second housing104. Additional examples of the vertical orientation202are illustrated inFIG. 3. In the horizontal orientation204, the first housing102may be located at the top (or the bottom) of the computing device100with the hinge106in the middle and the second housing104may be located at the bottom (or the top) of the computing device100. Additional examples of the horizontal orientation204are illustrated inFIG. 4.

FIG. 3is a block diagram illustrating different vertical orientations of a dual-housing computing device according to some embodiments. Additional examples of the vertical orientation202may include a book orientation302and a vertical tablet orientation304. For example, in a first book orientation302(1), the first housing102may be on the left and the second housing104may be on the right. Alternately, in a second book orientation302(2), the second housing104may be on the left and the first housing102may be on the right.

In the vertical tablet orientation304, the first housing102may be on the left and the second housing104may be on the right. In a first vertical tablet orientation304(1), the first housing102may be facing a user and the second housing104may be rotated approximately 360 degrees to face away from the user. In a second vertical tablet orientation304(2), the second housing104may be facing the user while the first housing102may rotated approximately 360 degrees to face away from the user.

FIG. 4is a block diagram illustrating different horizontal orientations of a dual-housing computing device according to some embodiments. Additional examples of the horizontal orientation204may include a tent orientation402, a presentation orientation404, a horizontal tablet orientation406, and a clamshell orientation408.

In402(1), the first housing102may be at the top facing the user while the second housing104may be at the bottom facing away from the user. In402(2), the second housing104may be at the top facing the user and the first housing102may be at the bottom facing away from the user.

In404(1), the first housing102may be at the top facing the user and the second housing104may be at the bottom facing down. In404(2) the second housing104may be at the top facing the user and the first housing102may be at the bottom facing down.

In406(1), the first housing102may be at the top facing the user and the second housing104may be at the bottom facing down (e.g., away from the user). In406(2), the second housing104may be at the top facing the user and the first housing102may be at the bottom facing down (e.g., away from the user).

In408(1), the first housing102may be at the top facing the user and the second housing104may be at the bottom facing the user (e.g., in a position where traditionally, a keyboard is located in a laptop). In408(1), in some cases, a QWERTY-based keyboard may be displayed on the second housing104and used to receive keyboard input. In408(2), the second housing104may be at the top facing the user and the first housing102may be at the bottom facing the user (e.g., in a position where traditionally, a keyboard is located in a laptop). In408(2), in some cases, a QWERTY-based keyboard may be displayed on the first housing102and used to receive keyboard input.

FIG. 5is a block diagram500illustrating a thermally and electrically conductive sheet of a computing device according to some embodiments. The conductive sheet158may be placed across the back of one or more of the housings102,104of the computing device100ofFIG. 1. For example, the conductive sheet158may have a length and width that is less than the length and width of one or more of the housings102,104. The conductive sheet158may be in contact with the vapor chamber156(or another type of heat sink used by one or more components housed in the first housing102).

If the hinges106are fairly small (e.g., a sum of the length of all the hinges106is less than 50% of the length of the longest side of one of the housings102,104), then the conductive sheet158may be a single sheet spanning both housings102,104, as illustrated inFIG. 5. A small portion of the conductive sheet158that spans the two housings102,104may be external to the computing device100. A spreader cover502that is made from a flexible material, such as leather, plastic, cloth, or the like, that is capable of insulating heat may be used to protect the exposed portion of the thermal spreader.

If the hinges106are not small (e.g., a sum of the length of all the hinges106is greater than or equal to 50% of the length of the longest side of one of the housings102,104), then the conductive sheet158may be a single sheet spanning both housings102,104, and the portion of the thermal spreader158that spans the two housings102,104may be threaded through openings (e.g., conduits) in the hinges106, and the spreader cover502may not be used.

The conductive sheet158may be electrically conductive for use as an electrical ground for communicating signals between components of the computing device102. Graphene has a conductivity of about 1×108Siemens per meter (S/m) while copper has a conductivity of about 6×107 (S/m). In some cases, impurities introduced during the manufacturing process may cause graphene to have a lower conductivity than 1×108 S/m, but this can be offset by doping the graphene, e.g., using potassium nitrate (KNO3), Lithium (Li), gold chloride (AuCl3), or other materials. In other cases, impurities may be removed from the graphene, using techniques such as, for example, centrifugation, filtration, precipitation, or decantation, to increase the electrical conductivity of graphene. Thus, graphene can be manufactured with similar or better electrical conductivity than copper, silver, annealed copper, gold, aluminum, and other metals.

FIG. 6is a block diagram600illustrating layers of a thermally and electrically conductive sheet according to some embodiments. For example, the conductive sheet158ofFIG. 1may include one or more layers, such as, for example, a first graphene layer602, a coverlay604, a conductive layer606, an insulation layer608, and a second graphene layer610.

One of the graphene layers602,610may be used for thermal conductivity (e.g., heat dissipation) while the other of the graphene layers602,610may be used for electrical conductivity (e.g., signal ground). For example, the graphene layer602may be used for thermal conductivity while the graphene layer610may be used for electrical conductivity. Alternately, the graphene layer610may be used for thermal conductivity while the graphene layer602may be used for electrical conductivity. The coverlay604may be a cover (e.g., a film) used to encapsulate and protect the inner layers606,608,610. The coverlay604may be flexible to enable the coverlay604to withstand being bent back and forth when passing through a hinge. The conductive layer606may be used to transmit signals and may be comprised of a conductor, such as, for example, copper, silver, aluminum, gold, or another type of metal or metal alloy.

One or more openings612, such as opening612(1) to612(N) (where N>1), may run vertically in the conductive sheet158to enable cables to be electrically connect to the conductive layer606and to whichever of the graphene layers602,610is being used as an electrical ground. For example, a cable614(1) may be routed through a shallow opening, such as the first representative opening612(1), to enable the cable614(1) to be connected to the conductive layer606(e.g., to transmit one or more signals or provide an electrical ground). A cable614(N) may be routed through a deeper opening, such as the second representative opening612(N), to enable the cable614(N) to be connected to the second graphene layer610(e.g., to transmit one or more signals or provide an electrical ground).

By using the conductive sheet158, (i) one or more layers of polyethylene terephthalate (PET), or Other thermoplastic polymer resin of the polyester family, may be eliminated, direct assembly of the conductive sheet158to circuit boards may be simplified, the heat spreading material in the conductive sheet158may be contiguous, the openings612may be used to connect cables (e.g., wires) in multiple locations, and an additional layer may be added for cable routing. For example, a routing layer616that sits on top of the first grapheme layer602may be used to route and hold in place the cables616(1) to616(N) in the computing device100.

FIG. 7is a block diagram illustrating a cross-sectional view of a thermally and electrically conductive cable700according to some embodiments. For example, the cable700may be used to communicate signals between the various components of the computing device100ofFIG. 1, including between the first housing102and the second housing104. The cable700may be run through conduits include the hinges106. The cable700may be used instead of or in addition to the conductive sheet158ofFIG. 1.

The cable700may include multiple layers, such as, for example, a conductor702, a first insulator704, a first graphene layer706, a second insulator708, a second graphene layer710, and a third insulator712. The conductor702may be used to transmit signals and may be comprised of, for example, copper, silver, aluminum, gold, or another type of metal or metal alloy. The insulators704,708,712may comprise a material that is electrically insulating, thermally insulating, or both. For example, the insulators704,708,712may comprise polyethylene, polytetrafluoroethylene (PTFE), or another similar type of insulator.

In some cases, the graphene layer706may provide both an electrical ground and thermal conductivity (e.g., to transfer heat from heat-generating components to areas of the computing device where the heat can dissipate). In other cases, the graphene layer706may provide an electrical ground while a second graphene layer710may provide thermal conductivity. For example, the second graphene layer710may be placed around the second insulator708. In some cases, an additional third insulator layer712may be placed around the second graphene layer710.

FIG. 8illustrates an example configuration of the computing device100ofFIG. 1that can be used to implement the systems and techniques described herein. The computing device100may include one or more processors802(e.g., the CPU112and the GPU114ofFIG. 1), the memory116, communication interfaces806(e.g., including the I/O ports120), the display devices108,110, other input/output (I/O) devices810(e.g., keyboard, trackball, and the like, such as the additional components144), and one or more mass storage devices812(e.g., including the memory116), configured to communicate with each other, such as via one or more system buses814(e.g., including the data bus128,130) or other suitable connections. While a single system bus is illustrated for ease of understanding, it should be understood that the system buses814may include multiple buses, such as a memory device bus, a storage device bus (e.g., serial ATA (SATA) and the like), data buses (e.g., universal serial bus (USB) and the like), video signal buses (e.g., ThunderBolt®, DVI, HDMI, and the like), power buses, etc.

The processors802are one or more hardware devices that may include a single processing unit or a number of processing units, all of which may include single or multiple computing units or multiple cores. The processors802may include the GPU114integrated into the CPU112or the GPU114may be a separate processor device from the CPU112. The processors802may be implemented as one or more microprocessors, microcomputers, microcontrollers, digital signal processors, central processing units, graphics processing units, state machines, logic circuitries, and/or any devices that manipulate signals based on operational instructions. Among other capabilities, the processors802may be configured to fetch and execute computer-readable instructions stored in the memory116, mass storage devices812, or other computer-readable media.

Memory116and mass storage devices812are examples of computer storage media (e.g., memory storage devices) for storing instructions that can be executed by the processors802to perform the various functions described herein. For example, memory116may include both volatile memory and non-volatile memory (e.g., RAM, ROM, or the like) devices. Further, mass storage devices812may include hard disk drives, solid-state drives, removable media, including external and removable drives, memory cards, flash memory, floppy disks, optical disks (e.g., CD, DVD), a storage array, a network attached storage, a storage area network, or the like. Both memory116and mass storage devices812may be collectively referred to as memory or computer storage media herein, and may be any type of non-transitory media capable of storing computer-readable, processor-executable program instructions as computer program code that can be executed by the processors802as a particular machine configured for carrying out the operations and functions described in the implementations herein.

The computing device100may also include one or more communication interfaces806for exchanging data via a network. The communication interfaces806can facilitate communications within a wide variety of networks and protocol types, including wired networks (e.g., Ethernet, DOCSIS, DSL, Fiber, USB etc.) and wireless networks (e.g., WLAN, GSM, CDMA, 802.11, Bluetooth, Wireless USB, ZigBee, cellular, satellite, etc.), the Internet and the like. Communication interfaces806can also provide communication with external storage, such as a storage array, network attached storage, storage area network, the cloud storage232, or the like.

The display devices108,110may be located in the housings102,104, respectively, and may be are connected using one or more hinges (e.g., the hinges106ofFIG. 1). The hinges may enable each display device to be placed at an angle relative to the other display device. For example, the display devices108,110may be used for displaying information and images to users. Other I/O devices810may be devices that receive various inputs from a user and provide various outputs to the user, and may include a keyboard, a touchpad, a mouse, a printer, audio input/output devices, and so forth.

The computer storage media, such as memory116and mass storage devices812, may be used to store software and data. For example, the computer storage media may be used to store an operating system816of the computing device100and software applications818. The memory116may also be used to store data820.

In some implementations, one or more of the computing components, such as the CPU112, the GPU114, or the memory116, may be in contact with a heat sink, such as the vapor chamber156. The vapor chamber156may be located in whichever housing is used to house components that generate the most amount of heat. For example, the vapor chamber156may be housed in the same housing as the CPU112.

The conductive sheet158(or the cable700) may be in contact with the vapor chamber156. The conductive sheet158(or the cable700) may conduct heat from heat generating components (e.g., CPU112, GPU114, or memory116), via contact with the vapor chamber156, to a second housing, where the heat is more easily dissipated because components in the second housing may generate less heat than the primary heat generating components (e.g. the housing that includes the CPU112). Thus, in a computing device with two housings, the conductive sheet158(or the cable700) may span both the first housing and the second housing and may draw heat from components in one housing and dissipate the heat in another housing. In a computing device with a single housing, the conductive sheet158(or the cable700) may draw heat from components in one area of the housing and dissipate the heat in another area of the housing.

The conductive sheet158may include one or more layers of a thermally and electrically conductive material, such as graphite/graphene to provide thermal cooling and an electrical ground. In addition, the conductive sheet158may include an electrically conductive layer that includes a metal alloy comprising copper, aluminum, another type of material, or any combination thereof. The electrically conductive layer may be used to communicate signals between different components of the computing device100. The conductive sheet158may use at least 3 portions, e.g., a first portion in the first housing, a second portion in the second housing, and a third portion that thermally connects the first portion to the second portion. The third portion of the conductive sheet158may be sufficient flexible to enable the first housing to be placed at an angle (e.g., preferably between about 0 to about 180 degrees or between about 0 to about 360 degrees) relative to the second housing. The third portion of the conductive sheet158may be capable of thermally conducting heat from the warmer housing to the cooler housing while enabling the first housing to be placed at different angles relative to the second housing. In addition, the third portion of the conductive sheet158may be designed to be repeatedly flexed (e.g., articulated) without breaking (or other damage) for an expected life of the computing device100. In some cases, the third portion of the conductive sheet158may be placed inside the one or more hinges. The conductive sheet158may be made of a flexible material, such as graphene, enabling a single graphene sheet to be used for both housings.

In some cases, when the hinges are fairly long, the conductive sheet158may be threaded through conduits in the hinges. In other cases, when the hinges are fairly small, a portion of the conductive sheet158may protrude outside the housings. In such cases, the exposed conductive sheet158(e.g., graphene sheet or other material) may be protected using a cover made out of leather, plastic, cloth, or other flexible material with insulating properties.

By using the conductive sheet158(or cable700) that spans both housings, the temperature difference between the two housings of the computing device100may be reduced to less than a pre-determined threshold (e.g., preferably less than 6 degrees Fahrenheit and more preferably less than 4 degrees Fahrenheit). For example, the temperature difference between the two sides of the computing device100may be reduced to a level that does not cause users to become sufficiently concerned to call customer service. Furthermore, the conductive sheet158(or cable700) may distribute the thermal load across both housings, approximately doubling the surface area available for thermal dissipation. By increasing thermal dissipation using the conductive sheet158(or cable700), components that use more power may be used in the design of the computing device100. The increased thermal dissipation may enable the computing device100to support computational components that consume more power (e.g., thereby generating more heat). For example, the conductive sheet158(or cable700) may enable the computing device100to support the CPU112with more cores and/or a faster clock speed, a more powerful (e.g., more pipelines, faster clock speed, or the like) GPU114, more memory116, a faster memory116, or any combination thereof.

The conductive sheet158(or cable700) may use one or more graphene layers to provide an electrical ground in addition to thermal conductivity. Graphene (or a graphene composite such as doped graphene) may be used as both a thermal solution and a signaling ground reference, thereby reducing the thickness of computing devices. Signals may be “sandwiched” between two layers of graphene to provide a continuous reference plane (for signal integrity) and ground coupling (for noise suppression). The graphene also provides a thermal solution to enable heat transfer between the two ends of the cable700or the conductive sheet158. Using graphene may provide several benefits, including reducing duplicate layers of plastic (e.g., polyethylene terephthalate or similar) material, simplifying assembly by enabling the conductive sheet158(or cable700) to be attached directly to circuit boards, providing a contiguous (e.g., uninterrupted) surface for thermal spreading, enabling connectors to be applied in multiple locations of the conductive sheet158(or cable700), and enabling one or more layers for cable routing to be added.