Patent Description:
When a form factor of the electronic speaker device is reduced, heat generated from electronic devices of the electronic speaker device can result in a thermal runaway condition that damages the electronic devices. To manage the heat generated from the electronic devices, a passive thermal-control system may be used. However, multiple challenges are presented regarding the design and architecture of an efficient and effective passive thermal-control system that prevents the thermal runaway condition while maintaining the reduced form factor.

<CIT> relates to a design for a compact home assistant with combined acoustic waveguide and heat sink. <CIT> relates to passive radiator cooling for electronic devices.

This document describes a passive thermal-control system that can be integrated into an electronic speaker device and associated electronic speaker devices. The passive thermal-control system uses an architecture that combines heat spreaders and thermal interface materials (TIMs) to transfer heat from heat-generating electronic devices of the electronic speaker device to a housing component of the electronic speaker device. The housing component dissipates the heat to prevent a thermal runaway condition.

The details of one or more implementations are set forth in the accompanying drawings and the following description. Other features and advantages will be apparent from the description, the drawings, and the claims. This summary is provided to introduce subject matter that is further described in the detailed description. Accordingly, a reader should not consider the summary to describe essential features nor limit the scope of the claimed subject matter.

The details of one or more aspects of a passive thermal-control system for an electronic speaker device and associated electronic speaker devices are described below. The use of the same reference numbers in different instances in the figures and drawings may indicate like elements.

This document describes a passive thermal-control system that can be integrated into an electronic speaker device and associated electronic speaker devices. The passive thermal-control system uses an architecture that combines heat spreaders and thermal interface materials to transfer heat from heat-generating electronic devices of the electronic speaker device to a housing component of the electronic speaker device. The housing component then dissipates the heat to prevent a thermal runaway condition.

Heat transfer, in general, is energy that is in transit due to a temperature difference. If one or more temperature differences exist across devices of a system, such as the electronic speaker device, heat (e.g., energy in Joules) will transfer from higher temperature zones to lower temperature zones to reduce the temperature differences. There are several mechanisms for heat transfer across the devices of the system to minimize temperature differences, including convection, radiation, and conduction.

Convection, or heat transfer from a surface due to movement of molecules within fluids such as gases and liquids, may be quantified by equation (<NUM>) below: <MAT>.

For equation (<NUM>), qconv represents a rate of heat transfer from a surface through convection (e.g., in Joules per second or Watts (W)), h represents a convection heat transfer coefficient (e.g., in W per meter squared (W/m<NUM>)), Ts represents a temperature of a surface (e.g., in Kelvin (K) or degrees Celsius (°C)), and T∞ represents a temperature of a fluid (e.g., in K or °C) to which the surface is exposed. The term A represents an area of a surface (e.g., in m<NUM>).

Radiation, or heat transfer from a surface through electromagnetic radiation, may be quantified by equation (<NUM>) below: <MAT>.

For equation (<NUM>), qrad represents a rate of heat transfer through radiation (e.g., in W), ε represents emissivity (dimensionless), σ represents the Stefen-Boltzmann constant (e.g., σ = <NUM> × <NUM>- <NUM> W/(m<NUM>·K<NUM>)), Ts represents a temperature of a surface (e.g., in K or °C), and Tsurr represents a temperature of surroundings of the surface (e.g., in K or °C). The term A represents an area of the surface (e.g., in m<NUM>).

Conduction, or heat transfer through a solid body through atomic and molecular activity, may be quantified by equation (<NUM>) below: <MAT>.

For equation (<NUM>), qcond represents a rate of heat transfer in a solid material through conduction (e.g., in W), k represents a thermal conductivity of the solid material (e.g., in W/(m·K)), and dT/dx represents a temperature gradient through the solid material (e.g., in K/m or °C/m). The term A represents a cross-sectional area of the solid material (e.g., in m<NUM>).

In instances of heat transfer from one physical body to another, through one or more of a convection heat-transfer mechanism, a radiation heat-transfer mechanism, or a conduction heat-transfer mechanism, the physical bodies may be in thermal contact. In some instances, this can include direct physical contact between the bodies or a material (e.g., a TIM) located between the bodies, enabling conduction-based heat transfer between the bodies. In other instances, this can include an air gap between the bodies that enables convection-based and/or radiation-based heat transfer between the bodies.

An electronic speaker device may include a passive thermal-control system that transfers heat using one or more of the heat-transfer mechanisms described above. In general, and in accordance with equations (<NUM>) and (<NUM>), rates and/or quantities of heat transfer can be varied by increasing or decreasing surface areas for convection and/or radiation within the electronic speaker device (e.g., increasing or decreasing surface areas of heat spreaders). In accordance with equation (<NUM>) and within the passive thermal-control system, rates and/or quantities of heat transfer can also be varied by introducing, between surfaces, one or more TIMs that have a high thermal conductivity.

Through conduction, convection, and/or radiation heat-transfer mechanisms, as described and quantified by equations (<NUM>) - (<NUM>) above, the passive thermal-control system may transfer heat originating from heat-generating electronic devices within the electronic speaker device to an interior surface of a housing component of the electronic speaker device. An exterior surface of the housing component may then dissipate the heat to an external environment through convection and/or radiation, effective to prevent a thermal runaway condition.

While features and concepts of the described passive thermal-control system for an electronic speaker device and associated electronic speaker devices can be implemented in any number of different environments and devices, aspects are described in the context of the following examples.

<FIG> illustrates an example operating environment <NUM> and an exploded view of an example electronic speaker device <NUM> having a passive thermal-control system <NUM>. In some instances, the electronic speaker device <NUM> may wirelessly connect to a wireless local area network (WLAN) using a wireless communication protocol (e.g., IEEE <NUM> (Wi-Fi)). Applications available through the electronic speaker device <NUM> and/or the WLAN (e.g., a remote cloud-computing application or service) may support a variety of functions, such as streaming audio (e.g., music, news, podcasts, sports) or interacting with a virtual assistant to perform tasks (e.g., search the Internet, schedule events and alarms, control home automation, control internet-of-things (IoT) devices).

The electronic speaker device <NUM> includes several elements, including a housing component <NUM>, an acoustic waveguide <NUM>, and a PCB <NUM>. The housing component <NUM> may form a portion of an oblate spheroid and, in some instances, include a substantially planar base. The acoustic waveguide <NUM> may be substantially planar and generally elliptical in shape. The PCB <NUM> may be substantially planar and generally elliptical in shape.

The housing component <NUM> may be perforated and include openings through which audio waves can travel (e.g., audio waves originating internally from a speaker of the electronic speaker device <NUM> or originating externally from a user of the electronic speaker device <NUM>). The housing component <NUM> may include a plastic material and be formed, for example, using plastic injection molding techniques. The acoustic waveguide <NUM> may guide the audio waves to a microphone and from the speaker within the electronic speaker device <NUM>. In some instances, the acoustic waveguide <NUM> may include a plastic material.

The PCB <NUM> may be formed, for example, using a glass-fiber-reinforced epoxy material (e.g., FR4). In some instances, the PCB <NUM> may include a single layer of electrically conductive traces and be a single-layer board. In other instances, the PCB <NUM> may be a multi-layer board that includes multiple layers of electrically conductive traces that are separated by layers of a dielectric material.

Multiple heat-generating electronic devices may be mounted to the PCB <NUM> and connected to the electrically conductive traces using surface mount and/or through-hole solder techniques. Example heat-generating electronic devices mounted to the PCB <NUM> include an SoC IC device, one or more memory devices, and audio-amplifier inductors. In some instances, each of the one or more memory devices may be a double data-rate random access (DDR DRAM) memory device. The multiple heat-generating electronic devices may further be mounted onto opposite surfaces of the PCB <NUM> (e.g., the SoC IC device and the memory IC devices may be mounted to a first surface of the PCB <NUM>, while the audio-amplifier inductors may be mounted to a second, opposite surface of the PCB <NUM>). In some instances, the PCB <NUM> may also include an electromagnetic interference (EMI) shield that surrounds heat-generating electronic devices such as the SoC IC device and the IC memory IC devices.

In general, the PCB <NUM> (including the multiple heat-generating electronic devices) may be considered an electronic subassembly of the electronic speaker device <NUM>. While the electronic speaker device <NUM> is operating, the multiple heat-generating electronic devices may generate heat that, if not dissipated quickly, can damage the electronic speaker device <NUM>.

This damaging situation, referred to as a thermal runaway condition, can have destructive impacts to the electronic speaker device <NUM> that include, for example, delamination of the PCB <NUM> and/or shortened life of devices of the electronic speaker device <NUM> (e.g., the SoC IC device, the memory IC devices, the audio-amplifier inductors, Wi-Fi devices, communication interfaces). In some instances, an operating temperature of the electronic speaker device <NUM> may exceed a prescribed temperature threshold, causing the electronic speaker device <NUM> to simply shut down (e.g., a thermocouple or other temperature sensing device may provide feedback to a processor or temperature-control unit of the electronic speaker device <NUM> and cause a thermal shut down).

To prevent the thermal runaway condition, the electronic speaker device <NUM> includes the passive thermal-control system <NUM> (e.g., a thermal-control system that is absent of active devices such as a powered fan, a powered pump exchanging fluids, and so on). The passive thermal-control system <NUM> includes multiple features, such as a first heat spreader <NUM> (e.g., a heat spreader in thermal contact with the housing component <NUM>), a second heat spreader <NUM> (e.g., a heat spreader in thermal contact with components populating the PCB <NUM>), and a third heat spreader <NUM> (e.g., a heat spreader in thermal contact with the acoustic waveguide <NUM>). The passive thermal-control system <NUM> may also include one or more TIMs that are located between surfaces of the heat-generating electronic devices and other elements of the passive thermal-control system <NUM> to provide a thermally conductive path, reduce air gaps, and lessen thermal resistance. Assembly techniques can integrate elements of the passive thermal-control system <NUM> of the electronic speaker device <NUM> to maintain a desired form factor and provide a desired thermal performance (e.g., a desired thermal response or temperature profile while the electronic speaker device <NUM> is operating).

The elements of the passive thermal-control system <NUM>, through a combination of heat-transfer mechanisms internal to the electronic speaker device <NUM> (e.g., conduction, convection, radiation), may transfer an internal heat load <NUM> (e.g., qi in W) from heat-generating electronic devices of the electronic speaker device <NUM> to the housing component <NUM> for dissipation to the surrounding operating environment <NUM> (e.g., dissipated using radiation and/or convection heat-transfer mechanisms).

In one example instance, the passive thermal-control system <NUM> may prevent a thermal runaway condition as the electronic speaker device <NUM> operates under the internal heat load <NUM> corresponding to a system power of up to <NUM> W. In this first example instance, a temperature (e.g., an ambient temperature) of the surrounding operating environment <NUM> may be approximately <NUM> and the passive thermal-control system <NUM> may spread, transfer, and dissipate heat to maintain a first temperature profile (e.g., a first temperature profile of heat-generating electronic devices of the electronic speaker device <NUM>) that is less than approximately <NUM>.

In another example instance, the passive thermal-control system <NUM> may prevent thermal runaway as the electronic speaker device <NUM> operates under another internal heat load <NUM> corresponding to a system power of up to <NUM> W. In this second example instance, a temperature (e.g., an ambient temperature) of the surrounding operating environment <NUM> may be approximately <NUM> and the passive thermal-control system <NUM> may spread, transfer, and dissipate heat to maintain a second temperature profile (e.g., a second temperature profile of heat-generating electronic devices of the electronic speaker device <NUM>) that is less than approximately <NUM>.

<FIG> illustrates a magnified view <NUM> of features included in the passive thermal-control system <NUM> of <FIG>. The magnified view <NUM> includes the first heat spreader <NUM>, the second heat spreader <NUM>, and the third heat spreader <NUM>. The third heat spreader <NUM> is foldable along a portion of a perimeter of an acoustic waveguide (e.g., the acoustic waveguide <NUM> of <FIG>) and is illustrated in an unfolded (e.g., flattened) view.

In general, each of the respective heat spreaders may each include one or more materials with high thermal-conduction properties. Example materials include graphite sheet materials, copper foil materials, and so on.

<FIG> illustrates details <NUM> of the housing component <NUM> and an example TIM <NUM> that may be used as part of a passive thermal-control system (e.g., the passive thermal-control system <NUM> of <FIG>). The housing component <NUM>, as illustrated in <FIG>, may form a portion of a generally oblate spheroid shell, and in some instances may generally be symmetrical about a central axis <NUM>.

As illustrated, the passive thermal-control system may include a TIM <NUM> located planar region <NUM> of the housing component <NUM> (e.g., located in a planar region corresponding to the first heat spreader <NUM> of <FIG> and <FIG>). The planar region <NUM>, in general, is orthogonal to the central axis <NUM>. In some instances, different portions of the TIM <NUM> may be in thermal contact with heat-generating devices mounted to a PCB (e.g., audio-amplifier inductors mounted to the PCB <NUM> of <FIG>).

Some examples of the TIM <NUM> include a thermally conductive gel or grease material, a thermally conductive foam material, or a thermal pad. In general, the use of the TIM <NUM> may reduce air gaps and/or bond line gaps while providing a thermal conduction path between the heat-generating devices and the housing component <NUM>.

In some instances, elements of an electronic speaker device (e.g., the electronic speaker device <NUM> of <FIG>) may be located proximate to the housing component <NUM> in one or more planes that are orthogonal about the central axis <NUM>. For example, an acoustic waveguide and a PCB (e.g., the acoustic waveguide <NUM> and the PCB <NUM> of <FIG>) may be located proximate to the housing component <NUM> in parallel planes that are orthogonal to the central axis <NUM>.

<FIG> illustrates details <NUM> of example heat spreaders that spread and transfer heat to the housing component <NUM>. The heat spreaders may include the first heat spreader <NUM> and the second heat spreader <NUM>.

The first heat spreader <NUM> may include a graphite material and/or a copper material. The first heat spreader <NUM> may be fixed to, and in thermal contact with, an interior surface of the housing component <NUM>. The first heat spreader <NUM> may, in general, be shaped like a segment of a ring having an exterior radius and an interior radius. Additionally, and when fixed to the interior surface of the housing component <NUM>, the first heat spreader <NUM> may conform to a curvature of the interior surface of the housing component <NUM>. The first heat spreader <NUM> may spread and transfer heat (e.g., heat from the heat-generating devices of the PCB <NUM> of <FIG>) to the interior surface of the housing component <NUM> for eventual dissipation through an exterior surface of the housing component <NUM>.

The second heat spreader <NUM> may include a graphite material and/or a copper material. The second heat spreader <NUM> is in thermal contact with one or more IC devices that may be mounted to a PCB (e.g., the PCB <NUM> of <FIG>). The second heat spreader <NUM> may also be in thermal contact with the interior surface of the housing component <NUM>.

The second heat spreader <NUM> includes a first portion <NUM> that traverses across surface profiles of the IC devices and is in thermal contact with surfaces of the IC devices. The first portion <NUM> may, in general, be shaped like a segment of a ring having an exterior radius and an interior radius. When fixed to the interior surface of the housing component <NUM>, the first portion <NUM> may conform to a curvature of the interior surface of the housing component <NUM>. In some instances, a TIM may be located between the first portion <NUM> and the IC devices to enhance thermal conductivity. In some instances, the first portion <NUM> may include a polyethylene terephthalate (PET) film material that is attached to surfaces of the first portion <NUM>.

The second heat spreader <NUM> also includes a second portion <NUM> that is in thermal contact with the interior surface of the housing component <NUM>. The second portion <NUM> may, in general, be rectangular in shape. The second heat spreader <NUM> may spread and transfer heat from the IC devices to the interior surface of the housing component <NUM> for eventual dissipation to a surrounding environment. In some instances, the second portion <NUM> may include an aluminum foil material that is attached to surfaces of the second portion <NUM>.

<FIG> illustrates details <NUM> of an example structure used to transfer heat from electronic devices mounted on a printed circuit board to an acoustic waveguide. The example structure may include the PCB <NUM> of <FIG>, the acoustic waveguide <NUM> of <FIG>, the second heat spreader <NUM> of <FIG>, the third heat spreader <NUM> of <FIG>, and an EMI shield (e.g., an EMI shield <NUM>).

As illustrated in the top view of <FIG>, the EMI shield <NUM> is attached to the PCB <NUM> (e.g., epoxied to the PCB <NUM>). Furthermore, the EMI shield <NUM> has an interior perimeter that surrounds at least one IC device mounted to the PCB <NUM> (e.g., an SoC IC device <NUM> and one or more memory IC device(s) <NUM>, hidden and "under" the second heat spreader <NUM>). The EMI shield <NUM>, in general, absorbs electromagnetic interferences in proximity of the SoC IC device <NUM> and the memory IC device(s) <NUM>.

Examples of materials that may be used to fabricate the EMI shield <NUM> include aluminum, copper, nickel, and stainless steel. In some instances, selection of the material used to fabricate the EMI shield <NUM> may account for a thermal conductivity property of the material.

The bottom view of <FIG> includes section-view A-A. Section-view A-A illustrates a cross-section of the structure in a region corresponding to the EMI shield <NUM>. Section-view A-A also incorporates a portion of the acoustic waveguide <NUM> (not illustrated in the top view). A bottom surface of the acoustic waveguide <NUM> includes portions of the third heat spreader <NUM>. The third heat spreader <NUM> may include a graphite material and/or a copper material.

As illustrated in section-view A-A, the structure includes the PCB <NUM>, an IC device mounted to the PCB <NUM> (e.g., the SoC IC device <NUM>), and an EMI shield <NUM> (e.g., an interior perimeter of the EMI shield <NUM>) is surrounding the SoC IC device <NUM>. Also, as illustrated in section view A-A, a first TIM (e.g., TIM <NUM>) is located between the SoC IC device <NUM> and a portion of the third heat spreader <NUM>. A second TIM (e.g., TIM <NUM>) is located between the EMI shield <NUM> and another portion of the third heat spreader <NUM>.

In the context of <FIG>, the first TIM <NUM> or the second TIM <NUM> may include combinations of a thermally conductive foam material, a thermally conductive gel material, or a thermally conductive grease material. As an example, in one instance, the first TIM <NUM> may include a thermally conductive grease material or thermally conductive gel material, while the second TIM <NUM> may include a thermally conductive foam material. As another example, the first TIM <NUM> may include a thermally conductive grease material or thermally conductive gel material, while the second TIM <NUM> may include a thermally conductive foam material.

Different combinations of TIMs are possible while assembling the structure of <FIG>. In some instances, the structure of <FIG> may also include a pressure-sensitive adhesive (PSA). For example, a PSA may coat exterior surfaces of the first TIM <NUM> if the first TIM <NUM> includes a thermally conductive foam material.

In some instances, and as also illustrated in <FIG>, the PCB <NUM> may be a double-sided PCB that is populated with heat-generating devices on opposite surfaces. For example, while the SoC IC device <NUM> is mounted to a first surface <NUM> of the PCB <NUM>, one or more audio-amplifier inductor(s) <NUM> may be mounted to a second surface <NUM> that is opposite the first surface <NUM>. A portion of a TIM (e.g., a portion of the TIM <NUM> of <FIG>) may be located between the devices on the second surface <NUM> of the PCB <NUM> (e.g., the one or more audio-amplifier inductor(s) <NUM>) and another surface (e.g., a surface of the first heat spreader <NUM> of <FIG>).

Furthermore, <FIG> illustrates a possible arrangement of the acoustic waveguide <NUM> relative to the PCB <NUM>. For example, and as illustrated, the first surface <NUM> onto which the SoC IC device <NUM> is populated faces the acoustic waveguide <NUM>.

<FIG> illustrates details <NUM> of an example heat spreader that may be part of the acoustic waveguide <NUM>. The heat spreader may be the third heat spreader <NUM> of <FIG>.

As illustrated by <FIG>, the acoustic waveguide <NUM> is assembled into the housing component <NUM>. The third heat spreader <NUM> may include graphite and/or copper materials that are foldable along a portion of a perimeter of the acoustic waveguide. The third heat spreader <NUM> includes a first portion <NUM>, a second portion <NUM>, and a third portion <NUM>. In aspects, the first portion <NUM> and the second portion <NUM> are each connected to the third portion <NUM>, and the first portion <NUM> is not connected to the second portion <NUM>. Further, a first flexible area connecting the first portion <NUM> to the third portion <NUM> may be proximate to a second flexible area connecting the second portion <NUM> to the third portion <NUM>. However, the first portion <NUM> and the second portion <NUM> may be located at any suitable location around the perimeter of the third portion <NUM>.

Folding and attaching the third heat spreader <NUM> to the acoustic waveguide <NUM> may include folding the different portions (e.g., first portion <NUM>, second portion <NUM>) of the third heat spreader <NUM> around different axes and attaching folded and unfolded portions to opposite surfaces of the acoustic waveguide <NUM>. As an example, the first portion <NUM> may fold around a first folding-axis <NUM> while the second portion <NUM> may fold around a second folding-axis <NUM>. Continuing, the first portion <NUM> (e.g., folded) and the second portion <NUM> (e.g., folded) attach to a surface of the acoustic waveguide <NUM>, while the third portion <NUM> (e.g., unfolded) attaches to an opposite surface of the acoustic waveguide <NUM>. The folding of the first portion <NUM> about the first folding-axis <NUM> and the second portion <NUM> about second folding-axis <NUM> effectuate a folding of the third heat spreader <NUM> about a portion <NUM> of a perimeter of the acoustic waveguide <NUM>. Respective shapes of the first portion <NUM>, second portion <NUM>, and third portion <NUM> may include multiple radiuses and/or holes to avoid interferences with features that may be present in regions of attachment to the surfaces of the acoustic waveguide <NUM>.

Attaching the portions of the third heat spreader <NUM> (e.g., the first portion <NUM>, the second portion <NUM>, the third portion <NUM>) to the acoustic waveguide <NUM> may include using an epoxy material, a PSA material, and so on. After attachment, the first portion <NUM> and the second portion <NUM> share an overlapping region <NUM>.

In general, the example of the third heat spreader <NUM> of <FIG> can be referred to as a "double-flap" configuration. The double-flap configuration of <FIG> affords a substantially round shape of the acoustic waveguide <NUM>, reducing tooling setups and manufacturing costs of the acoustic waveguide <NUM>. In this instance, the round shape of the acoustic waveguide <NUM> also increases available surface area of the acoustic waveguide <NUM> in comparison to other potential shapes of the acoustic waveguide <NUM> (e.g., other shapes of the acoustic waveguide <NUM> may include a truncated radius or a square edge). This increase in available surface area improves heat transfer performance (conduction, convection, radiation) of the third heat spreader <NUM> attached to the acoustic waveguide <NUM>.

The third heat spreader <NUM> of <FIG> may also include features such as one or more wings (e.g., wing <NUM>, illustrated as a dashed line) that extend beyond a perimeter of the acoustic waveguide <NUM> and that are in thermal contact with an interior surface of the housing component <NUM>. Fabricating the third heat spreader <NUM> to include selective materials can, in some instances, tune heat transfer performance of the third heat spreader <NUM> (e.g., fabricating the third heat spreader <NUM> to include a material with high emissivity (ε) properties can improve thermal radiation performance of the third heat spreader <NUM>).

Through such a combination of the aforementioned elements, the third heat spreader <NUM> of <FIG> can spread and transfer heat generated by IC devices (e.g., the SoC IC device <NUM> and the memory IC device(s) <NUM> of <FIG>) to the housing component <NUM> for eventual dissipation external to the electronic speaker device <NUM> (e.g., dissipation through convection). The dissipation of the heat will prevent thermal runaway of heat-generating electronic devices of the electronic speaker device <NUM>.

<FIG> illustrates details <NUM> of another example heat spreader that may be part of the acoustic waveguide <NUM>. The heat spreader may be the third heat spreader <NUM> of <FIG>.

As illustrated by <FIG>, the acoustic waveguide <NUM> is assembled into the housing component <NUM>. The third heat spreader <NUM> may include foldable graphite and/or copper materials. The third heat spreader <NUM> may include a first portion <NUM> and a second portion <NUM>.

In the context of <FIG>, attaching the third heat spreader <NUM> to the acoustic waveguide <NUM> may include folding portions of the third heat spreader <NUM> around an axis and attaching different portions of the third heat spreader <NUM> to opposite surfaces of the acoustic waveguide <NUM>. As an example, the first portion <NUM> may fold around folding-axis <NUM>. The folding of the third heat spreader <NUM> about the folding-axis <NUM> effectuates a folding of the third heat spreader <NUM> about a portion <NUM> of a perimeter of the acoustic waveguide <NUM>.

Continuing, the first portion <NUM> may attach to a surface of the acoustic waveguide <NUM>, while the second portion <NUM> may attach to an opposite surface of the acoustic waveguide <NUM>. Attaching the portions of the third heat spreader <NUM> (e.g., the first portion <NUM> and the second portion <NUM>) to the acoustic waveguide <NUM> may include using an epoxy material, a PSA material, and so on. Respective shapes of the first portion <NUM> and the second portion <NUM> may include multiple radiuses and/or holes to avoid interferences with features that may be present in regions of attachment to the surfaces of the acoustic waveguide <NUM>.

In general, the example of the third heat spreader <NUM> of <FIG> can be referred to as a "single-flap" configuration (e.g., a single-flap folded about the folding-axis <NUM>). The single-flap configuration of <FIG> may be desirable in instances where a reduction in cost of the third heat spreader <NUM> is desirable over costs and/or performance considerations with respect to the acoustic waveguide <NUM>.

The third heat spreader <NUM> of <FIG> may also include features such as one or more wings (e.g., wing <NUM>, illustrated as a dashed line) that extend beyond a perimeter of the acoustic waveguide <NUM> and that are in thermal contact with an interior surface of the housing component <NUM> to improve heat transfer from the acoustic waveguide <NUM> to the interior surface of the housing component <NUM>. Depending on materials of the third heat spreader <NUM>, the third heat spreader <NUM> may also be tuned to improve radiation (e.g., a material with high emissivity (ε) properties may be chosen).

Through such a combination of the aforementioned elements, the third heat spreader <NUM> spreads and transfers heat generated by IC devices (e.g., the SoC IC device <NUM> and the memory IC device(s) <NUM> of <FIG>) to the housing component <NUM> for eventual dissipation. The dissipation of the heat can contribute to preventing a thermal runaway condition.

Claim 1:
An electronic speaker device (<NUM>) comprising:
a housing component (<NUM>);
an acoustic waveguide (<NUM>), the acoustic waveguide (<NUM>) generally planar;
a printed circuit board (<NUM>) including at least one integrated circuit device (<NUM>, <NUM>), the printed circuit board (<NUM>) generally planar; and
a passive thermal-control system (<NUM>) to transfer heat generated by the at least one integrated circuit device (<NUM>, <NUM>) to the housing component (<NUM>), the passive thermal-control system (<NUM>) comprising:
a first heat spreader (<NUM>) in thermal contact with the printed circuit board (<NUM>);
a second heat spreader (<NUM>) in thermal contact with the at least one integrated circuit device (<NUM>, <NUM>); and
a third heat spreader (<NUM>) in thermal contact with the acoustic waveguide (<NUM>), the third heat spreader (<NUM>) foldable along a portion (<NUM>; <NUM>) of a perimeter of the acoustic waveguide (<NUM>) to enable the third heat spreader (<NUM>) to be in thermal contact with two opposing surfaces/sides of the acoustic waveguide (<NUM>).