Heat dissipation features, electronic devices incorporating heat dissipation features, and methods of making heat dissipation features

Electronic devices incorporating a heat dissipation feature include an enclosure, and at least one heat-generating component positioned within the enclosure. The heat dissipation feature is sufficiently coupled to the at least one heat-generating component to facilitate conductive heat transfer from the heat-generating component. The heat dissipation feature includes a plurality of protrusions exposed externally to the enclosure. A thermally insulating material may be disposed on at least a tip portion of at least some of the protrusions. The thermally insulating material is selected to provide a touch temperature that is below a predetermined threshold. In some instances, the thermally insulating material can provide such a touch temperature by selecting the material to include properties for thermal conductivity (k), density (ρ), and specific heat (Cp) such that the product of k*ρ*Cp results in a value less than a product of k*ρ*Cp for human skin.

BACKGROUND

Various features disclosed herein pertain generally to electronic devices, and at least some features pertain to devices and methods for facilitating heat dissipation for electronic devices.

As handheld and portable electronic devices increase in capability and functionality, the electronics within the devices must provide improved computational performance levels. In order to achieve these higher computational performance levels, such electronic devices must dissipate increasing amounts of energy in the form of heat. Due to the compact size of typical devices, this energy can rapidly heat the device, causing discomfort or even injury to the user who is touching the device (e.g., with hands, face, body).

Human skin can be sensitive to the heat dissipated by the device surface. Conventionally, electronic thermal management systems employ multiple temperature sensors to monitor and manage the overall temperature of the device. When the temperature becomes excessive, software and/or hardware may restrict (e.g., throttle down) the overall performance of the device by reducing the computational performance of the integrated circuits. Because of the sensitivity of human skin to the heat dissipated by the device surface, the thermal management typically starts restricting the device (processor) performance once the temperature of the enclosure reaches about 45° C. This restriction can become a major limitation to performance. For example, the frame rate of graphics or video may be restricted, the speed of computation and/or responsiveness of an application may be restricted, etc.

Another conventional solution to thermal management involves fan-forced active cooling to improve heat transfer, but this option is limited in practicality and is expensive. Fan forced cooling systems can result in increased power consumption to energize the forced air, and may also increase the size of the device housing, noise, and reliability. Air cooling is also limited by the small form factor of many portable electronic devices.

SUMMARY

Various features facilitate heat dissipation in electronic devices, such as portable electronic devices. One aspect provides electronic devices including an enclosure and at least one heat-generating component positioned within the enclosure. A heat dissipation feature is thermally coupled to the one or more heat-generating components to facilitate conductive heat transfer from the heat-generating component. The heat dissipation component includes a plurality of protrusions exposed externally to the enclosure, and a thermally insulating material disposed on at least a tip portion of at least some of the plurality of protrusions. The thermally insulating material may be selected to provide a touch temperature that is below a predetermined threshold.

According to at least one further aspect, heat dissipation features are provide, which are adapted for use in electronic devices. Such heat dissipation features can include a base adapted to facilitate conductive heat transfer from a heat-generating component. A plurality of protrusions may extend from the base, where the protrusions are adapted for exposure external to an enclosure of an electronic device. A thermally insulating material may be disposed on at least a tip portion of at least some protrusions of the plurality of protrusions. The thermally insulating material may be selected to comprise respective values for properties of thermal conductivity (k), density (ρ), and specific heat (Cp) such that a product of these values (k*ρ*Cp) is less than a product of values for the same properties k*ρ*Cpfor human skin

In yet further aspects, methods of making electronic devices are included. According to at least one example, such methods may include forming a base and a plurality of protrusions extending from the base. A thermally insulating material may be disposed on at least a tip portion of at least some of the protrusions. The thermally insulating material may comprise respective values for properties of thermal conductivity (k), density (ρ), and specific heat (Cp) such that a product of these values (k*ρ*Cp) is less than a product of values for the same properties k*ρ*Cpfor human skin. The base may be disposed in relation to at least one heat-generating component so as to facilitate conductive heat transfer from the heat-generating component to the base and the plurality of protrusions.

According to further aspects, electronic devices are provided, where the electronic devices include means for conductively transferring heat from a heat-generating component positioned within an enclosure to an environment external to the enclosure. Means are also included for providing a touch temperature that is below a predetermined threshold.

DETAILED DESCRIPTION

The illustrations presented herein are, in some instances, not actual views of any particular protrusions, heat dissipation features or electronic devices, but are merely idealized representations which are employed to describe various aspects relating to the present disclosure. Additionally, elements common between figures may retain the same numerical designation.

Overview

Electronic devices including a heat dissipation feature are presented, where the heat dissipation feature is adapted to facilitate the conductive transfer of heat from a heat-generating component within an enclosure of the electronic device to an environment external to the enclosure. The heat dissipation feature includes a thermally insulating material disposed on a surface of a plurality of protrusions to protect a user of the electronic device from discomfort and/or injury that may be caused by the temperature of the heat dissipation feature that is exposed to the environment external to the enclosure. The thermally insulating material is selected to provide a touch temperature that is below a predetermined threshold. In some instances, the thermally insulating material can provide such a touch temperature by selecting the material to include properties for thermal conductivity (k), density (ρ), and specific heat (Cp) such that the product of k*ρ*Cpresults in a value less than a product of k*ρ*Cpfor human skin.

Electronic Devices

Various aspects of the present disclosure include electronic devices adapted to facilitate the transfer of heat from internal components to an area external to the electronic device. Referring toFIG. 1, an isometric view of an electronic device100is shown according to at least one example. As illustrated, the electronic device100includes an enclosure102and a heat dissipation feature104.

According to at least one feature, the electronic device100can be adapted for portability. That is, the electronic device100may be a portable and/or handheld electronic device, although the electronic device may also be at least substantially stationary according to various embodiments.FIG. 8is a block diagram illustrating some examples of electronic devices. InFIG. 8, an electronic device is shown as a mobile telephone802, a portable computer804, and a fixed location remote unit806in a wireless local loop system. As shown, the electronic devices can communicate with each other either directly or by way of one or more relay devices808. Referring again toFIG. 1, by way of example and not limitation, the electronic device100may be implemented as a mobile phone, a smart phone, a session initiation protocol (SIP) phone, a laptop, a notebook, a netbook, a smartbook, an ultrabook, a tablet, an e-book reader, a personal digital assistant (PDA), a global positioning system (GPS) device, a navigation device, a multimedia device, a video device, a music player, an entertainment unit, a set-top box, a fixed location data unit such as a meter reading equipment, a camera, a game console, or any other electronic device that may come into contact with a user's skin when used. Although various examples of electronic devices are illustrated and/or described herein, the disclosure is not limited to these examples. Aspects of the present disclosure may be suitably employed in any electronic device which is adapted to come into contact with a user's skin during use. The electronic device100may also include other features that are not shown, such as a user interface (e.g., touch screen, display, keyboard, mouse), an input interface for connecting one or more input devices, an output interface for connecting one or more output devices, etc.

The enclosure102is sized and shaped to house one or more electronic components of the electronic device100. For instance, the enclosure102may be configured to at least substantially enclose one or more electronic components. The enclosure102can be formed of any of a plurality of suitable materials, or combination of materials. For example, the enclosure102may be formed from a metal or metal alloy, a polymer, glass, as well as any other suitable material, or any combination of materials.

The heat dissipation feature104, which may also be characterized as a heat dissipation component, can be disposed at one or more different sides of the enclosure102. The heat dissipation feature104may be disposed to form an entire surface of the enclosure102(e.g., an entire surface of the back side opposite a display, an entire side surface, etc.), or the heat dissipation feature104may be disposed at only a portion of a surface of the enclosure102. The specific size and shape of the heat dissipation feature104can vary according to the particular implementation and varying design requirements.

Generally speaking, one or more heat dissipation features104are exposed at an outer surface106of the enclosure102. In at least some examples, at least a portion of a heat dissipation feature104may be exposed through an aperture (e.g., the aperture206inFIG. 2) formed in a portion of the enclosure102. In one or more other examples, a heat dissipation feature104may be integrally formed with the enclosure and exposed at the outer surface106thereof.

Turning toFIG. 2, a cross-sectioned elevation view is shown taken at section A-A inFIG. 1according to at least one example where a heat dissipation feature104ais exposed through an aperture206in the enclosure102. As illustrated, the enclosure102is a distinct structure from the heat dissipation feature104a. In some examples, the heat dissipation feature104acan be abutted to the enclosure102with a plurality of protrusions204exposed through the aperture206. In other examples, the heat dissipation feature104acan be positioned proximate to the enclosure102, without necessarily touching the enclosure. In such instances, one or more additional structures may be positioned between the heat dissipation feature104aand the enclosure102, so long as the plurality of protrusions204are exposed through the aperture206.

Turning toFIG. 3, a cross sectioned elevation view is shown taken at section A-A inFIG. 1according to at least one example where a heat dissipation feature104bis integral to the enclosure102. As illustrated, the heat dissipation feature104bcan be formed integrally with the enclosure102and exposed to an external environment.

Turning toFIG. 7, a cross sectioned elevation view is shown taken at section A-A inFIG. 1according to at least one example where a heat dissipation feature104cis integral with a package702of a heat-generating component202. As illustrated, the heat dissipation feature104ccan be integrally incorporated with a package702for the heat-generating component202. In such examples, the packaging702which includes the heat dissipation feature104ccan be exposed through an aperture of an enclosure (e.g., as illustrated inFIG. 2), or the packaging702can be formed integral to an enclosure (e.g., as illustrated inFIG. 3.

Referring toFIGS. 2,3, and7, various features will be described relating to one or more examples of heat dissipation features104of the present disclosure, where a heat dissipation feature104may comprise the structures of104a,104band/or104c, but are not so limited. The heat dissipation feature104is configured to facilitate conductive heat transfer from one or more heat-generating components202inside the enclosure102to the environment external to the enclosure102, where such heat energy can be dissipated at least by convection to the external environment. The heat dissipation feature104may, in some examples, be configured as a heat sink.

As illustrated inFIGS. 2,3, and7, the heat dissipation feature104is thermally coupled with a heat-generating component202. As used herein, the term “thermally coupled” refers to a coupling (e.g., mechanical or otherwise) that facilitates heat transfer from the heat-generating component202to the heat dissipation feature104. A heat-generating component202may include any electronic and/or mechanical component within the enclosure102that generates heat. In at least some examples, the heat-generating component202may be one or more integrated circuits, such as a central processing unit (CPU) and/or a graphics processing unit (CPU). In other examples, the heat-generating component202may be one or more analog components such as power amplifiers, power converters, thermoelectric Peltier device, and/or photon emitting sources. Although the illustrated examples show the heat-generating component202with a smaller footprint than the heat dissipation feature104, other examples may employ a heat-generating component with a footprint that is equal to or larger than a footprint of the heat dissipation feature104.

Generally speaking, the heat dissipation feature104is sufficiently coupled to the heat-generating component202to facilitate conductive heat transfer from the heat-generating component202. In some examples, the heat dissipation feature104is thermally coupled to the heat-generating component202by being positioned adjacent to the heat-generating component202. In other examples, the heat-generating component202is thermally coupled to the heat dissipation feature104by being laterally offset from the heat dissipation feature104(not shown) and coupled via a thermally conductive strip, sheet, pipe, and/or some other suitable means. In still other examples, the heat dissipation feature104(e.g., heat dissipation feature104c) is thermally coupled to the heat-generation component202by being formed integral to a component packaging. In further examples (not shown), the heat dissipation feature104is thermally coupled to the heat-generating component202by being positioned with one or more other thermal-conductive elements positioned between the heat dissipation feature104and the heat-generating component202. In one such example, the heat generating component may comprise a flip chip including an active face (i.e. a first side) and a substrate (i.e. an opposing second side), where the substrate is coupled to the heat dissipation feature104. The active face of such a flip chip may generate heat on its own and/or may experience heat due to its exposure to heat dissipated through a second integrated circuit coupled to the flip chip's active face. In this example, the flip chip (i.e. the heat generating component202) may be thermally coupled to the heat dissipation feature104through the substrate, which substrate may include thermally conductive vias disposed therein. In all of the various examples, heat from the heat-generating component202is conductively transferred from the heat-generating component202to the heat dissipation feature104. In any or all examples, other functional elements such as RF shielding, conformal coating and/or temperature sensors may be applied between or adjacent to the heat-generation component202and the heat dissipation feature104.

As shown inFIGS. 2,3, and7, the heat dissipation feature104includes a plurality of protrusions204coupled to a base208, and extending generally away from the heat-generating component202. The protrusions204are exposed externally to the enclosure102to increase the surface area at the outer surface106of the enclosure102. That is, the protrusions204are exposed to an environment external to the enclosure102, and generally form at least a portion of the outer surface106of the enclosure102. As shown in the example inFIG. 2, the heat dissipation feature104can be exposed through an aperture206formed in the enclosure102. In other examples, such as the example shown inFIG. 3, the heat dissipation feature104can be formed integrally with the enclosure102and exposed to an external environment.

Each of the protrusions204may be formed by a plurality of fins (also identifiable by element204) extending from the base208that is conductively coupled with the heat-generating component202to facilitate the conductive heat transfer from the heat-generating component202. Each of the protrusions204is separated from the other protrusions204by a plurality of depressions210located between each of the plurality of protrusions.

The protrusions204may comprise any of a plurality of sizes and shapes. For instance, the protrusions204may be formed with a rectangular cross-section (as shown), a triangular cross-section, an ovate cross-section, or other cross-sectional shape, as well as combinations of different shapes. Similarly, the depressions210may be formed with any of a plurality of cross-sectional shapes, such as rectangular (as shown), triangular, ovate, or other shapes, as well as combinations of different shapes. According to at least some examples, the protrusions204can be formed to extend across the entire heat dissipation feature104. For instance,FIG. 4is an enlarged isometric view of a heat dissipation feature104showing protrusions204that extend across the length ‘L’ of the heat dissipation feature104. In other examples, the protrusions204may be formed to only extend a portion of the width of the heat dissipation feature104. For instance,FIG. 5illustrates an enlarged isometric view of a heat dissipation feature104including protrusions204configured as posts (or pins). According to various examples, the protrusions204implemented as posts may be configured with any of a variety of shapes, including circular posts (as shown), square posts, rectangular posts, pyramid-shaped posts, elliptical posts, etc. as well as any combination of differently shaped posts.

Referring again toFIGS. 2,3, and7, the protrusions204can be configured to extend about equal to the enclosure102in at least some examples. For instance, in various examples the protrusions204are sized and shaped to extend a distance equal to an outside surface of the enclosure102. In other examples, the protrusions204can be configured to extend a distance less than the outside surface of the enclosure102. For example, the protrusions204can be sized and shaped to be depressed below the outside surface of the enclosure102, so that there is little or no contact with a user's skin. In still other examples, the protrusions204can be configured to protrude beyond the outside surface of the enclosure102. In yet further examples, as depicted inFIG. 9, the protrusions204may be configured to extend different distances, so that some protrusions204extend a further distance than other protrusions204. In other words, the heat dissipation feature104can be formed with at least some longer protrusions204and at least some shorter protrusions204. According to at least one feature, the protrusions204can be generally sized and shaped such that the heat dissipation feature104does not significantly increase the size (e.g., the thickness) of the enclosure102and can be implemented with relatively small (e.g., thin) enclosures102.

According to a feature, the heat dissipation feature104further includes a thermally insulating material214disposed on at least a tip portion of at least some of the plurality of protrusions204. Generally speaking, the thermally insulating material214is a material selected to protect the user of the electronic device100from discomfort and/or injury (e.g., burns) that may be caused by the relatively high temperature of the heat dissipation feature104that is exposed to the environment external to the enclosure102. Accordingly, the thermally insulating material214is positioned on at least the surface or surfaces that may come into contact with a user's skin, which surface is generally referred to herein as the tip portion of the protrusions204. Accordingly, the thermally insulating material214can be disposed on at least a relatively small surface of the protrusions204. The portion of a protrusion204including the tip portion may vary depending on the particular orientation (e.g., horizontal and/or vertical orientation) of the protrusions204.

The portions of the protrusions204that do not have a thermally insulating material214disposed thereon may include areas that are small enough to protect the user from exposure to the relatively high temperature of the heat dissipation feature104. Those areas of the protrusions204that are at least substantially free from the thermally insulating material214(e.g., side surfaces of the protrusions204) can facilitate heat dissipation to the external environment.

In examples where the protrusions204are configured to extend different lengths (some longer protrusions204and some shorter protrusion204), the thermally insulating material214may be disposed on at least the tip portions of those protrusions204extending a sufficient length to come into contact with a user's skin as depicted inFIG. 9. However, the protrusions204that extend a shorter length such that the shorter protrusions204will not come into contact with the user's skin may not have any thermally insulating material214disposed thereon as also depicted inFIG. 9. In some examples, the thermally insulating material214can also be disposed over one or more portions of an outside surface of the enclosure102.

The thermally insulating material214employed in various examples of the present disclosure can be selected to provide a touch temperature that is equal to, or below some predetermined threshold. In at least some examples, the predetermined threshold may be about 45° C. In other examples, the predetermined threshold may be a temperature less than, or equal to about 60° C. This predetermined threshold can be associated with a predefined power dissipation value from one or more heat-generating components202of the electronic device100and/or for a given temperature at the outer surfaces106of the heat dissipation feature104. For example, the thermally insulating material214can be selected to provide a touch temperature that is equal to, or below the predetermined threshold, when the temperature at the outer surfaces106of the heat dissipation feature104falls in a range from about 175° C. and below (e.g., between about 0° C. and about 175° C.).

The touch temperature refers to the actual temperature felt by the user's skin, as opposed to the measured temperature at the outer surfaces of the heat dissipation feature104. Touch temperature (T(touch) or Ttouch) can be described mathematically by the equation

The portion of the equation expressed by k*ρ*Cprepresent values for thermal conductivity (k), density (ρ), and specific heat (Cp) being multiplied together.

The variable (k*ρ*Cp) skin refers to the value of k*ρ*Cpfor human skin. According to at least one example, human skin can be characterized as having a thermal conductivity (k) of about 0.2 W/(m*K), a density (ρ) of about 1,000 kg/m3, and a specific heat (Cp) of about 2,500 J/(kg*K). Accordingly, the product of k*ρ*Cpfor human skin is about 500,000 (J*W)/(m4*K2).

The variable T(skin) (or Tskin) refers to the temperature of human skin. This temperature can be characterized as about 36.6° C. for at least some examples.

The variable (k*ρ*Cp) insulation refers to the value of k*ρ*Cpfor the thermally insulating material214.

The variable T(surface) (or Tsurface) refers to the temperature at the outer surfaces106of the heat dissipation feature104. This temperature is often a result of the junction temperature of the heat-generating component202, as a result of the power dissipation of the heat-generating component202. Accordingly, this temperature may be calculated and/or measured according to the various design constraints of the electronic device100. According to the above equation, the touch temperature can result in a value that is lower than the measured temperature at the outer surfaces of the heat dissipation feature104(Tsurface).

In some examples, attaining a touch temperature at or below the predetermined threshold may be accomplished by selecting a thermally insulating material214that has properties for thermal conductivity (k), density (ρ), and specific heat (Cp) which, when multiplied together (k*ρ*Cp), result in a value that is less than the same product for human skin. As noted above, the product of k*ρ*Cpfor human skin may be determined to be about 500,000 (J*W)/(m4*K2). The thermally insulating material214can therefore be selected to comprise a value for k*ρ*Cpthat is less than about 500,000 (J*W)/(m4*K2).

By way of example and not limitation, the thermally insulating material214may comprise a silicone rubber, polypropylene, high density polyethylene, polyurethane, and microcellular polymer foams. According to at least some examples, the thermally insulating material214may generally be of a light and insulative material.

Conventional electronic devices do not include a heat dissipation feature as described herein. Instead, the enclosure of most conventional electronic devices simply includes a relatively flat surface. As internal electronic components dissipate heat, the conventional enclosure typically heats up and the junction temperature for one or more internal electronic components may need to be controlled to avoid damage to the internal electronic component and/or to avoid discomfort or injury to the skin of the user. In such conventional electronic devices, the heat at the outer surface of the enclosure is primarily dissipated by convective heat transfer, and is therefore limited by the surface area of the enclosure. By employing a heat dissipation feature104, the protrusions204increase the surface area at the outer surface106of the enclosure102, resulting in improved heat dissipation.

For instance, in one example a conventional electronic device having an internal component operating at a particular power level such that the internal component is dissipating 3 watts (W) was found to have a junction temperature of 64.1° Celsius (C) and a temperature of 62.4° C. at the outer surface of the device enclosure, in the case of natural convection at the outer surface. By incorporating a heat dissipation feature104according to aspects of the present disclosure, a similarly configured internal component operating at the same power level where it is dissipating 3 watts was found to result in a junction temperature of just 44.3° C. and a temperature of 43.6° C. at the outer surfaces106of the heat dissipation feature104of the enclosure102, in the case of natural convection. As shown by this example, the junction temperature is significantly decreased, enabling the heat-generating component202to dissipate greater amounts of power, and the temperature at the outer surface is also significantly decreased.

This improved heat dissipation enables heat-generating components202to operate more efficiently and at higher power levels, but does not necessarily protect the user's skin from discomfort and/or injury (e.g., burns). Accordingly, the selection of the thermally insulating material214can result in even farther protection to the user, and can enable a heat generating component to dissipate significantly greater amounts of power without causing discomfort and/or injury to the user's skin.

In at least one example, the thermally insulating material211is a fiber glass material having a value for k*ρ*Cpof about 3,005 (J*W)/(m4*K2). By incorporating this value into the touch temperature equation above, the touch temperature is equal to about Tskin*0.928+Tsurface*0.072. As noted in the example set forth above for a heat-generating component202dissipating about 3 watts, the outer surfaces106of the heat dissipation feature104was measured at 43.6° C. Furthermore, the temperature for human skin can be estimated at about 36.6° C. Using these values in the present example, the resulting touch temperature is about 37.1° C. Therefore, although the measured temperature at the outer surfaces106of the heat dissipation feature104is 43.6° C., the temperature felt by the user's skin is only about 37.1° C. In addition, significant increases of the junction temperature, resulting in an increase to the temperature at the outer surfaces106will have only a small effect to the touch temperature. For instance, an increase in the temperature a the outer surfaces106to 100° C. will only increase the touch temperature to about 41.2° C. In examples where the predetermined threshold is 45° C., the touch temperature of about 41.2° C. is still within the predetermined threshold. Thus, an electronic device100can employ high performance internal components that use significant amounts of power and dissipate enough heat to increase the temperature at the outer surfaces106of the heat dissipation feature104to temperatures as high as 100° C. without exceeding the threshold value of 45° C.

It will be apparent to a person of ordinary skill in the art that selecting the thermally insulating material214to be a material just having a low value for thermal conductivity is not sufficient to significantly reduce the touch temperature. For instance, a cement plaster material may exhibit a relatively low thermal conductivity of just 0.7 W/(m*K), but the product of k*ρ*Cpfor cement plaster is about 1.456×106(J*W)/(m4*K2). Using this value in the equation for touch temperature for the previous example results in a touch temperature of about 41° C., which is a relatively small reduction from the 43.6° C. of the measured temperature at the outer surfaces106. Furthermore, an increase in the temperature at the outer surfaces106to 100° C. results in an increase of the touch temperature to about 76.6° C., which may cause significant discomfort and/or injury to a user's skin.

According to another feature, by selecting the thermally insulating material214according to its values for the properties of thermal conductivity (k), density (ρ), and specific heat (Cp), the thermally insulating material214is further adapted to protect a user's skin against power surges. Such a power surge may cause an increase in the junction temperature and the temperature at the outer surfaces106. However, the thermally insulating material214is adapted to facilitate a touch temperature that is increased only slightly by such a power surge.

Methods of making Electronic Devices with Heat Dissipation Features

Various aspects of the present disclosure also relate to methods of making electronic devices with heat dissipation features.FIG. 6is a flow diagram illustrating at least one example of a method of making an electronic device, such as the electronic device100, including a heat dissipation feature. Referring toFIGS. 2,3,6, and7, a base208is formed and a plurality of protrusions204are formed extending therefrom, at step602. According to various implementations, the protrusions204can be formed to extend across the entire base208of a heat dissipation feature104(as illustrated inFIG. 4) and/or as a plurality of posts (as illustrated inFIG. 5).

The base208and the protrusions204can be formed as an integral unit, or the protrusions201can be formed separately, and subsequently coupled to the base208. According to various implementations, the base208and protrusions204can be formed by extrusion, machining, casting, molding, or other manufacturing means, as well as combinations thereof.

The base208and the protrusions204can be formed from one or more materials adapted to facilitate the conduction of heat. For instance, the base208and the protrusions204may be formed of one or more materials having a relatively high value for thermal conductivity, such as a heat-conductive polymer, metal, metal alloy, composite, etc. In at least some non-limiting examples, the base208and the protrusions204may be formed of an aluminum alloy, copper, diamond (natural or synthetic), copper-tungsten pseudoalloy, silicon carbide in aluminum matrix (AlSiC), diamond in copper-silver alloy matrix (dymalloy), beryllium oxide in beryllium matrix (e-material), etc. In some examples, the base208and the protrusion204may be formed of different materials. For instance, the base208may be formed of a first material and the protrusion204may be formed of a second material.

In at least some implementations, the base208, and in some instances the protrusions204, can be formed as an integral part of an enclosure102and/or as an integral part of a package702for the heat-generating component202. In some instances, the base208can be coupled to an aperture206of an enclosure102. The protrusions204can be formed to extend a distance at least substantially equal to an outside surface of the enclosure102in some examples. In other examples, the protrusions204can be formed to be depressed below the outside surface of the enclosure102. In still other examples, the protrusions204can be formed to protrude beyond the outside surface of the enclosure102.

At step604, a thermally insulating material214is disposed on at least the tip portion of the plurality of protrusions. As discussed above, the thermally insulating material211can be selected to provide a touch temperature that is below a predetermined threshold, according to the touch temperature equation discussed above. In at least some examples, the thermally insulating material214can be selected to include properties for thermal conductivity (k), density (ρ), and specific heat (Cp) such that a product of values for these three properties (k*ρ*Cp) results in a value less than a product of values for the same properties (k*ρ*Cp) for human skin. In other words, the thermally insulating material214can be selected so that the product (k*ρ*Cp) for the thermally insulating material214is lower than the product of (k*ρ*Cp) for human skin.

The thermally insulating material214may be disposed on at least the tip portion of the plurality of protrusions204in any of a plurality of different operations. By way of example and not limitation, the thermally insulating material214can be disposed on at least the tip portion of the protrusions204by extruding the thermally insulating material214together with the protrusions204, by coupling the thermally insulating material214to at least the tips of the protrusions204, by depositing the thermally insulating material214on at least the tips of the protrusions204, etc. Some processes for disposing the thermally insulating material214on at least the tips of the protrusions204may include etching the thermally insulating material214away from areas (e.g., of the protrusions and/or of the enclosure) where the thermally insulating material214is not intended to remain.

At step606, the base208is coupled to at least one heat-generating component202to facilitate conductive heat transfer from the heat-generating component202to the base208and the plurality of protrusions204. As noted previously, the base208can be directly coupled to the heat-generating component202, formed integral to a package702of the heat-generating component, and/or one or more other thermal-conductive elements may be disposed between the base208and the heat-generating component202. In each instance, heat from the heat-generating component202is conductively transferred from the heat-generating component202to the base208and to the protrusions204.

According to an aspect, the base208and protrusions204, the thermally insulating material214, and the at least one heat-generating component202can be integrated into one or more electronic devices.

It is noted that, although the forgoing method is depicted as a flow diagram showing the various steps as a sequential process, at least some of the forgoing acts can be performed in another sequence, in parallel, or substantially concurrently. In addition, the order of the acts may be re-arranged. For a firmware and/or software implementation of one or more steps in the forgoing method, the processes may be implemented with modules (e.g., procedures, functions, and so on) that perform the functions described herein. Any machine-readable medium tangibly embodying instructions may be used in implementing the processes described herein. For example, software codes may be stored in a memory and executed by a processor unit. Memory may be implemented within the processor unit or external to the processor unit. As used herein the term “memory” refers to any type of long term, short term, volatile, nonvolatile, or other memory and is not to be limited to any particular type of memory or number of memories, or type of media upon which memory is stored.

The various features of the examples described herein can be implemented in different constructions and arrangements without departing from the scope of the disclosure. It should be noted that the forgoing embodiments are merely examples and are not to be construed as limiting the disclosure. The description of the examples is intended to be illustrative, and not to limit the scope of the claims. As such, the present teachings can be readily applied to other types of apparatuses and many alternatives, modifications, and variations will be apparent to those skilled in the art.