Glasses arm design

Abstract

An arm of a head-mountable display may include an arm tip, an arm hinge, and a housing. The housing may include a first surface and a second surface opposite the first surface, wherein the housing defines an interior volume spanning between the arm tip and the arm hinge. The arm of the head-mountable display may also include a printed circuit board (PCB) positioned inside the interior volume, a heat source attached to the PCB, and a thermal path inside the interior volume. In some cases, the thermal path inside the interior volume is directed from the heat source through the first surface and the arm hinge and towards the ambient environment.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 366,530, filed on June 16, 2022, and entitled “GLASSES ARM DESIGN,” the entire disclosure of which is hereby incorporated by reference. Technical Field

[0003] The described embodiments generally relate to eyeglass arms. More specifically, embodiments of the invention relate to managing thermal energy of electronic eyeglasses. Background Art

[0004] Thermal ergonomics is a challenge for eyewear electronics (e.g., head-mountable electronics). Specifically, thermal ergonomics is an increasing challenge as eyewear electronics are designed with reduced form factors, which often pulls thermal components closer to the user, which can increase user discomfort. Thus, improvements are needed to reduce the amount of heat transferred to the user. Additionally, improvements are needed to reduce component (e.g., battery) degradation caused by increased internal temperatures. Summary of the invention

[0005] One aspect of the present disclosure relates to an arm of a head-mounted display, the arm comprising an arm tip, an arm hinge, and a housing. The housing may include a first surface and a second surface opposite the first surface, wherein the housing defines an internal volume spanning between the arm tip and the arm hinge. The arm of the head-mounted display may also include a printed circuit board (PCB) positioned inside the internal volume, a heat source attached to the PCB, and a thermal path inside the internal volume. In some cases, the thermal path inside the internal volume is directed from the heat source through the first surface and the arm hinge and toward the surrounding environment.

[0006] In some examples, the arm of the head-mountable display includes a base connecting the PCB to the arm hinge, wherein the thermal path is directed from the heat source through the PCB, through the base, through the arm hinge, and toward the surrounding environment. Additionally or alternatively, the arm of the head-mountable display includes a thermal interface material and a heat diffuser material positioned above the heat source and the PCB. According to some examples, the thermal path can be directed from the heat source through the thermal interface material, through the heat diffuser material, through the first surface, and toward the surrounding environment.

[0007] In one or more examples, the first surface and the heat source define an air gap within the internal volume. In this example, the thermal path can be directed from the heat source through the air gap, through the first surface, and toward the surrounding environment. Additionally, in some examples, the heat source is positioned closer to the first surface than the second surface. Furthermore, in some examples, the heat source is oriented toward the first surface.

[0008] The arm of the head-mountable display may include various components. For example, the arm of the head-mountable display may include a battery positioned between the PCB and the second surface, wherein the PCB, the battery, and the second surface are spatially separated by corresponding air gaps.

[0009] Another aspect of the present disclosure relates to a head-mounted device. In some examples, the head-mounted device may include a display, an arm housing connected to the display, and an arm subassembly disposed in the arm housing. In a specific example, the arm housing includes a heat dissipation surface oriented toward the surrounding environment. In addition, in some examples, the arm subassembly may include a base, a PCB attached to the base, and a system-on-chip (SoC) mounted on the PCB and oriented toward the heat dissipation surface.

[0010] In one or more examples, the arm housing includes a seamless one-piece housing defining an interior volume between an arm tip and an arm hinge, wherein the arm hinge connects the arm subassembly to the display. Additionally, in some examples, the arm housing includes an assembly access to the interior volume, wherein the assembly access can be positioned proximate to the arm hinge.

[0011] In some examples, a portion of the heat dissipation surface inside the arm housing includes a thermal liner adjacent to the arm subassembly. In some cases, the thermal liner draws heat away from the arm assembly and directs it toward the heat dissipation surface.

[0012] In one or more examples, the arm subassembly further comprises a thermal insulator disposed between the PCB and a surface of the arm housing opposite the heat dissipation surface. Additionally or alternatively, the arm subassembly further comprises a thermal interface material and an epoxy molding compound.

[0013] Another aspect of the present disclosure relates to a heat flow device for an augmented reality (AR) glasses arm. In some examples, the heat flow device for the AR glasses arm includes a PCB, a heat source attached to the PCB, and at least one of a heat interface material or a heat diffuser material positioned above the heat source and the PCB.

[0014] In one or more examples, the heat flow device of the AR glasses arm includes a heat dissipation surface oriented toward the surrounding environment, the heat diffuser material lining the inner portion of the heat dissipation surface, and the heat interface material positioned between the heat diffuser material and the heat source. Additionally or alternatively, the heat flow device of the AR glasses arm may include an arm hinge and a base, which thermally connects the PCB, the heat interface material, the heat diffuser material and the arm hinge. In some examples, the first portion of the epoxy resin molding compound is positioned between the heat interface material and the heat source and the PCB. In addition, in some examples, the second portion of the epoxy resin molding compound is positioned between the PCB and the surface opposite to the heat dissipation surface. In one or more examples, an insulator is positioned between the second portion of the epoxy resin molding compound and the surface.

[0015] In one or more examples of the heat flow device, at least one of the heat interface material or the heat diffuser material directs heat energy away from the heat source and toward the surrounding environment via at least one of natural conduction or unforced convection. In a specific example, the heat flow device also includes a heat dissipation surface, wherein the heat diffuser material includes at least one of a pitch-based carbon fiber material, a graphite material, or a copper material lined on the heat dissipation surface. In some examples, the heat dissipation surface spans between the arm tip and the arm hinge, wherein the heat diffuser material diffuses the heat load from the heat source onto the heat dissipation surface. In some examples, the heat flow device also includes a heat path away from the heat source, across the fibers of the pitch-based carbon fiber material, and toward the surrounding environment to reach the heat dissipation surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] The present disclosure will be readily understood through the following detailed description in conjunction with the accompanying drawings, in which like reference numerals represent like structural elements, and in which:

[0017] Figure 1 to Figure 2 Illustrated is a top view of an example of a head-mountable display worn on a user's head.

[0018] Figure 3 A cross-sectional top view of an example arm of a head mountable display is illustrated.

[0019] Figure 4 A cross-sectional top view of an example arm of a head mountable display is illustrated.

[0020] Figure 5 A cross-sectional top view of an example arm of a head mountable display is illustrated.

[0021] Figure 6 A cross-sectional top view of an example arm of a head mountable display is illustrated.

[0022] Figure 7Experimental results of implementing the thermal path during test operations are illustrated. DETAILED DESCRIPTION

[0023] The following description is not intended to limit the examples to a preferred embodiment. On the contrary, the following description is intended to cover substitutions, modifications and equivalents that may be included in the essence and scope of the examples defined by the appended claims. Reference will now be made specifically to the representative examples illustrated in the accompanying drawings.

[0024] The following disclosure relates to a head-mountable display. Examples of head-mountable displays may include virtual reality or augmented reality devices having optical components. In the case of an augmented reality device, optical glasses may be worn on a user's head such that the optical lenses and / or optical displays are located in front of the user's eyes. In another example, a virtual reality device may be worn on a user's head such that a display screen is located in front of the user's eyes.

[0025] In a specific example, a head-mounted display includes a display for presenting visualizations, an arm housing (or shell) connected to the display, and an arm subassembly inserted into the interior of the arm housing. The arm housing can interface with the user to fix the display in an appropriate position (e.g., in front of the user's eyes). In one example, the arm housing extends from the arm tip to the arm hinge. The arm tip can be positioned behind the user's ear. The arm hinge can be connected to the display hinge for rotatably connecting the arm housing to the display.

[0026] The arm subassembly may include various components for operating the head-mounted display. Example components of the arm subassembly include a microphone, a speaker, a battery, a printed circuit board (PCB), a system on a chip, etc. Other example components of the arm subassembly include a base and a hinge connection. As will be discussed below, the arm subassembly may include additional or alternative components (e.g., heat-related components).

[0027] The operation of the head-mountable display generates heat. For example, when the system-on-chip (SoC) performs operations to generate visualization via the display, the system-on-chip architecture inside the arm housing can generate heat. The disclosed devices and apparatuses direct this heat in a predetermined manner.

[0028] For example, the head-mounted display of the present disclosure directs heat away from the user, resulting in an improved user experience in at least some cases. In practice, conventional arm designs of electronic glasses suffer from undesirable heat transfer to the skin of the user wearing the electronic glasses (e.g., around the user's temple or ear area). This undesirable heat transfer may be particularly severe during computationally intensive operations or longer operating durations of conventional electronic glasses. In contrast, the head-mounted display of the present disclosure can improve the user experience by predictably directing thermal energy away from the user and toward the surrounding environment.

[0029] As another example of thermal guidance, a head-mounted display can be designed to direct heat away from device components. To illustrate, a head-mounted display can direct heat away from a battery inside an arm housing. In more detail, battery life in a system can decrease over time due to exposure to increased temperature levels. Therefore, a head-mounted display can extend the battery life of the head-mounted display by reducing heat exposure to the battery. In this way, the head-mounted display can increase the life of the battery and other temperature-sensitive components.

[0030] The head-mounted display can direct heat in a variety of different ways. In some examples, the head-mounted display includes one or more of a base, a hinge, an air gap, an insulating material, a thermal interface material, a heat diffuser material, a heat sink, etc. to direct heat in a predetermined manner. It should be understood that the head-mounted display can utilize various different combinations, configurations, and arrangements of such components (or designs) to provide desired thermal ergonomics. In a specific example, the head-mounted display includes a specific combination of the foregoing to provide a specific thermal path (e.g., away from the user or device components). As an example, the head-mounted display includes a thermal path that travels from a heat source mounted to the PCB, through the world-facing surface of the arm housing, and toward the surrounding environment.

[0031] The following will refer to Figures 1 to 7 To discuss these examples and other examples. However, those skilled in the art will readily appreciate that the detailed description of these figures given herein is for illustrative purposes only and should not be construed as limiting. In addition, as used herein, a system, method, article, component, feature, or sub-feature comprising at least one of a first option, a second option, or a third option should be understood to refer to a system, method, article, component, feature, or sub-feature that may include one of each listed option (e.g., only one first option, only one second option, only one third option), multiple of a single listed option (e.g., two or more first options), two options at the same time (e.g., one first option and one second option), or a combination thereof (e.g., two first options and one second option).

[0032] Figure 1 to Figure 2 A top view of an example of a head-mountable display 100 worn on a user's head 101 is illustrated. The head-mountable display 100 may include a display 102 (e.g., one or more optical lenses or display screens in front of the user's eyes). The display 102 may include a display for presenting an augmented reality visualization, a virtual reality visualization, or other suitable visualization.

[0033] The head-mounted display 100 may also include one or more arms 104, 106 or bands. The arms 104, 106 are connected to the display 102 and extend distally toward the back of the head 101. The arms 104, 106 are configured to fix the display 102 in a certain position relative to the head 101 (e.g., so that the display 102 is maintained in front of the user's eyes). For example, the fixed arms 104, 106 extend above the user's ears 103. In some examples, the arms 104, 106 are placed on the user's ears 103 to fix the head-mounted display 100 via friction between the arms 104, 106 and the head 101. Additionally or alternatively, the arms 104, 106 may be placed against the head 101. For example, the arms 104, 106 may apply relative pressure to the sides of the head 101 to fix the head-mounted display 100 to the head 101. Additionally, the arms 104 , 106 may be attached to a strap or other securing feature that secures the circumference or majority of the head mountable display to the head 101 .

[0034] The terms “proximal” and “distal” may be used to refer to the location of various components of the devices described herein relative to the display 102 of the head mountable display 100. The orientation of the “proximal” and “distal” directions relative to the devices described herein is in the Figure 1 Shown in.

[0035] like Figure 2 As shown, the head mountable display 100 includes an arm member 202 disposed within the arms 104, 106. The arm member 202 may include a variety of different components. In a specific example, the arm member 202 includes electronic components for operating the head mountable display 100. For purposes of illustration, the arm member 202 includes a microphone, a speaker, a battery, a printed circuit board (PCB), a system on a chip, etc. It should be understood that such components may generate visualizations for presentation via the display 102. The arm member 202 may also include structural components, such as a base or a hinge connection. In addition, as will be discussed below, the arm member 202 may include heat-related components to conduct heat. Reference Figure 2 Additional details on heat dissipation are provided.

[0036] like Figure 2 As shown, the head mountable display 100 generates heat 204. The generation of heat 204 or thermal energy may occur as part of normal operation of the head mountable display 100. For example, the head mountable display 100 generates heat 204 in response to the arm member 202 processing computer executable instructions to generate a visualization presented via the arm member 202.

[0037] Despite such heat generation, the head-mountable display 100 can dissipate the heat 204 toward the surrounding environment 206. The surrounding environment 206 refers to the area surrounding the user (e.g., the head 101). In one example, such directional heat dissipation away from the head 101 can contribute to an improved user experience. For example, the head-mountable display 100 can dissipate the heat 204 via the outward-facing surface 208 of the arms 104, 106 oriented toward the surrounding environment 206. In doing so, the head-mountable display 100 can reduce the heat dissipated through the inward-facing surface 210 of the arms 104, 106 oriented toward the head 101. This reduced heat dissipation through the inward-facing surface 210 is particularly useful because the inward-facing surface 210 can be in close contact or close proximity with the head 101. Therefore, the head-mountable display 100 can reduce exposure to uncomfortable temperature levels of the head 101.

[0038] Although in Figure 2 204 in directions relative to certain components of the arm component 202. In fact, as will be discussed below with respect to subsequent figures, the head mountable display 100 can dissipate heat in directions (or along thermal paths) that reduce thermal exposure to temperature sensitive components (such as a battery).

[0039] Figure 1 to Figure 2 Any of the features, components, and / or parts shown (including their arrangements and configurations) may be included alone or in any combination in any other examples of devices, features, components, and parts shown in other figures described herein. Similarly, any of the features, components, and / or parts shown or described with reference to other figures (including their arrangements and configurations) may be included alone or in any combination in any other examples of devices, features, components, and parts shown in other figures described herein. Figure 1 to Figure 2 Examples of devices, features, components and parts are shown below. Figure 3 Further details are provided on the structural configuration of the arms that direct thermal energy away from sensitive components and / or a user.

[0040] Figure 3 A cross-sectional top view of an example arm 300 for a head-mounted display is illustrated. The arm 300 may be similar to the one described above with respect to Figure 1 to Figure 2 The arms 104, 106 discussed are identical or similar.

[0041] As shown, the arm 300 includes a housing 302. As used herein, the term "housing" or "housing" refers to the main body portion of the arm 300. In some examples, the housing 302 defines an outer shell or surface profile of the arm 300. Specifically, the housing 302 may include a first surface 306 oriented toward the surrounding environment 206 and a second surface 308 oriented toward the user's head 101. The first surface 306 and the second surface 308 may extend at least partially between the arm tip 310 and the arm hinge 312. In some cases, the first surface 306 and the second surface 308 span the entire distance between the arm tip 310 and the arm hinge 312.

[0042] As used herein, the term "arm tip" refers to an end region of the arm 300, as defined by the housing 302. The arm tip 310 can be positioned behind the ear of the user. Additionally or alternatively, the arm tip 310 can be pressed against the user's head 101 for securing a head-mountable display. The arm tip 310 is positioned opposite another end region of the arm 300 that is adjacent or connected to the arm hinge 312.

[0043] Additionally, as used herein, the term "arm hinge" refers to the connection between the arm 300 and the display 102 ( Figure 1 to Figure 2 Further details about the arm hinge 312 will be discussed below.

[0044] In some examples, the housing 302 comprises a unitary housing. For example, the first surface 306 and the second surface 308 form an integral or combined body. To illustrate one example, the first surface 306 and the second surface 308 may be combined, matched, or joined together so that the housing 302 forms a single shell. As another example, the first surface 306 and the second surface 308 refer to discrete portions, sides, or regions of the otherwise non-discrete entire body of the arm 300. It should be understood that forming the housing 302 may be achieved in a variety of different ways (e.g., casting, injection molding, three-dimensional printing, machining, etc.).

[0045] In addition, the housing 302 may include a variety of different materials. In some examples, the housing 302 includes a metal material. For example, the housing 302 may include one or more base metals, such as titanium, stainless steel, tungsten, cobalt, aluminum, copper, lead, nickel, tin, zinc, gold, silver, etc. Additionally or alternatively, in some examples, the housing 302 may include materials other than metals. For example, the housing 302 may include a polymer material, a carbon fiber material, a glass material, etc. Combinations of the foregoing materials are also contemplated herein. For example, in addition to one or more coatings, the housing 302 may be composed of one or more base materials.

[0046] Further Figure 3As shown, the housing 302 can define an assembly inlet 314 into an interior volume 316 within the arm 300. The assembly inlet 314 can be positioned in a number of different locations along the arm 300. For example, as illustrated, the assembly inlet 314 is positioned near the arm hinge 312. As an alternative example, the assembly inlet 314 can be positioned at the arm tip 310. In yet another example, the assembly inlet 314 can be positioned between the arm tip 310 and the arm hinge 312. In some examples, the size and shape of the assembly inlet 314 can be designed to allow the arm subassembly 304 to be inserted into the interior volume 316.

[0047] As used herein, the term "arm subassembly" refers to components inside the arm 300. In certain examples, the arm subassembly 304 can include components assembled together as a unit for insertion into the housing 302. In some examples, the arm subassembly 304 includes a base 318, a printed circuit board (PCB) 320, and a system on a chip (SoC) 322. Each will be discussed in turn.

[0048] The term "base" refers to one or more components connected to the arm hinge 312. In certain examples, the base 318 is configured to bear loads from one or more components mounted thereto. In some examples, the base 318 transfers or distributes this load to the arm hinge 312. Additionally, as will be discussed below, the base 318 can include thermally conductive properties for heat transfer.

[0049] The base 318 can include a variety of different materials. In some examples, the base 318 includes a metallic material. For example, the base 318 includes one or more base metals, such as titanium, stainless steel, tungsten, cobalt, aluminum, copper, lead, nickel, tin, zinc, gold, silver, etc. Additionally or alternatively, in some examples, the base 318 includes a material other than a metal. For example, the base 318 includes a polymer material, a carbon fiber material, a diamond material, a graphite material, a silicon carbide material, etc. Combinations of the foregoing materials are also contemplated herein. For example, a portion of the base 318 connected to the hinge may include a metallic material, and another portion of the base 318 may include a polymer material (e.g., Figure 6 shown).

[0050] The term "PCB" or "printed circuit board" refers to a logical assembly that includes electronic components. PCB 320 includes electrical connectors and circuits for mounting various components, including SoC 322. PCB 320 may also transfer power from a power source (e.g., a battery, Figure 3320 is a main logic board (not shown) relayed to mounted electrical components. In some examples, PCB 320 is a main logic board. PCB 320 can be a rigid board (e.g., composed of a glass epoxy resin compound). In some examples, PCB 320 is a multi-layer PCB (e.g., a laminated sandwich structure of conductive layers and insulating layers). In some examples, PCB 320 is flexible (e.g., having a flexible circuit made of polyimide). In some examples, PCB 320 includes reinforcements added via lamination or pressure-sensitive adhesives.

[0051] The terms "SoC," "system on chip," or "heat source" refer to an electronic chip that generates heat energy during operation. In some examples, SoC 322 may include a microchip to generate (e.g., drive) the heat generated by the display 102 ( Figure 1 to Figure 2 322). It should be understood that the thermal energy or heat generated by the SoC 322 may become greater over the duration of use. Similarly, the thermal energy or heat generated by the SoC 322 may become greater when performing more data-intensive operations (e.g., for more complex or high-fidelity visualizations).

[0052] like Figure 3 As shown, heat from SoC 322 generally flows in direction 324 toward the surrounding environment 206 and away from the user's head 101. As discussed above, this heat flow has various advantages. In order to guide the heat flow in direction 324, arm 300 can implement a variety of different methods. In some examples, arm 300 implements at least one of natural conduction or unforced convection to create a thermal path for dissipating heat. In some examples, arm 300 implements both natural conduction and unforced convection to create a thermal path for dissipating heat.

[0053] As used herein, the term "thermal path" refers to heat flow. A thermal path may be exemplified as linear or direct. However, a thermal path is not limited to such a flow path. In fact, as a function of the thermal properties of a given medium (whether solid, liquid or gas), a thermal path may be linear or curved (e.g., non-linear). In addition, a thermal path is not limited to two-dimensional space. It should be understood that the thermal path of the present disclosure includes a three-dimensional thermal path that passes through a given volume.

[0054] The term "natural conduction" refers to heat transfer via conductively connected components. The term "unforced convection" refers to free or natural convection, in which air movement is caused by natural buoyancy due to density changes caused by changes in thermal temperature in the air. Unforced convection is distinguished from forced convection, in which a fluid (e.g., air) is forced to flow by an internal source such as a fan (through agitation) or a pump to produce artificially induced convection.

[0055] For illustration, the thermal path 328 is directed from the SoC 322, through the air gap 326 (e.g., via non-forced convection), through the first surface 306, and toward the ambient environment 206. The size and formation of the distance between the first surface 306 and the SoC 322 defining the air gap 326 can be designed to provide desired thermal ergonomics. For example, the air gap 326 can be reduced to create a smaller thermal resistance between the SoC 322 and the first surface 306. Additionally, the air gap 326 can be increased to ensure that the SoC 322 is mechanically decoupled from the housing 302 (e.g., so that the SoC 322 is not subjected to external loads applied to the arm 300). It should therefore be understood that the air gap 326 is not limited to a constant distance between the first surface 306 and the SoC 322. In fact, the air gap 326 may be smaller in some areas of the arm 300 and larger in other areas.

[0056] In some examples, air gap 326 includes about 0.2 millimeter (mm) gap to about 10 mm gap. In some examples, air gap 326 includes about 0.2 mm gap to about 1 mm gap. In a specific example, air gap 326 includes about 0.4 mm gap to about 0.5 mm gap.

[0057] Other thermal paths are also contemplated herein. For example, thermal path 330 can be directed from SoC 322, through PCB 320, through base 318, through arm hinge 312, and toward ambient environment 206. Although thermal path 330 does not utilize air gap 326, thermal path 330 corresponds to a conduction path between components in direct contact. Specifically, thermal path 330 utilizes the thermal conductivity of PCB 320, base 318, and arm hinge 312 to transfer heat toward ambient environment 206. Therefore, in one or more examples, thermal path 330 (as a conduction path) transfers heat from SoC 322, through PCB 320, and through arm hinge 312. The thermal conductivity properties of these components can be adjusted or optimized to provide desired thermal ergonomics.

[0058] Furthermore, it should be understood that heat transfer using the base 318 and the arm hinge 312 is not limited to natural conduction. For example, another heat path may be directed from the SoC 322, through the air gap 326 (via unforced convection), through the base 318, through the arm hinge 312, and toward the ambient environment 206. Further, the following description of Figures 4 to 5 Discussion of Additional Thermal Paths Thus, arm 300 may utilize multiple different thermal paths as desired.

[0059] In some examples, arm 300 implements a single thermal path. In other examples, arm 300 implements a combination of multiple thermal paths. The combination of thermal paths can be designed to dissipate a certain ratio of thermal energy. For example, a thermal path can be designed to distribute a larger amount of thermal energy than another thermal path. For illustration but only one example, thermal path 328 can distribute 80% of the heat load to the surrounding environment 206, and thermal path 330 can distribute 10% of the heat load to the surrounding environment 206 (and 10% can not be distributed by any thermal path). These ratios of thermal paths 328, 330 can be reversed (i.e., vice versa), modified or adjusted to achieve desired thermal ergonomics. In fact, surface area, thermal conductivity, etc. can be modified to provide a specific ratio of thermal energy distribution between thermal paths. In other examples, each thermal path is designed to distribute an equal amount of thermal energy to the surrounding environment 206.

[0060] The arm subassembly 304 can be arranged in a variety of different ways within the arm 300 to provide these or other thermal paths. For example, in some examples, the SoC 322 is positioned closer to the first surface 306 than the second surface 308. In some implementations, the SoC 322 is positioned as far away from the second surface 308 as possible (or as close to the first surface 306 as possible without coupling). Some example distances between the SoC 322 and the first surface 306 are discussed above with respect to the air gap 326.

[0061] As an additional example, the SoC 322 can be oriented toward the first surface 306. In other words, the SoC 322 can be mounted to the PCB 320 such that the SoC 322 is positioned between the first surface 306 and the PCB 320. In this example, the PCB 320 can be positioned between the SoC 322 and the second surface 308.

[0062] The position and configuration of the arm subassembly 304 can also help reduce undesirable heat paths. For example, by positioning the SoC 322 closer to the first surface 306 than the second surface 308, the arm 300 can transfer (or distribute) a greater heat load to the surrounding environment 206 rather than to the user's head 101. Similarly, by orienting the SoC 322 toward the first surface 306 (as opposed to the second surface 308), the arm 300 can transfer (or distribute) a greater heat load to the surrounding environment 206 rather than to the head 101.

[0063] Figure 3Any of the features, components, and / or parts shown (including arrangements and configurations thereof) may be included alone or in any combination in any other examples of devices, features, components, and parts shown in other figures described herein. Similarly, any of the features, components, and / or parts shown or described with reference to other figures (including arrangements and configurations thereof) may be included alone or in any combination in any other examples of devices, features, components, and parts shown in other figures described herein. Figure 3 Examples of devices, features, components and parts are shown below. Figure 4 Further details of example arm configurations and their heat dissipation designs are provided.

[0064] Figure 4 A cross-sectional top view of an example arm 400 for a head-mounted display is illustrated. The arm 400 may be similar to the one described above with respect to Figure 1 to Figure 2 The arms 104, 106 discussed are identical or similar.

[0065] As shown in the figure, arm 400 includes Figure 3 The first surface 306 and the second surface 308 of the present invention define the housing 302. In addition, the arm 400 includes an arm subassembly 402, which includes the arm subassembly also described above with respect to Figure 3 PCB 320 and SoC 322 discussed. In addition, although not in Figure 4 , the arm 400 spans between the arm tip and the arm hinge, as described above with respect to Figure 3 The arm tip 310 and arm hinge 312 are similarly described.

[0066] However, with Figure 3 Instead, arm subassembly 402 includes (or interfaces with) one or more optional components, such as thermal interface material 404, heat spreader 406, or element 408. Each will be discussed in turn.

[0067] As used herein, the term "thermal interface material" refers to a material inserted between components or surfaces to enhance the thermal connection between the components or surfaces. Examples of thermal interface material 404 include thermal epoxy, thermal paste, thermal adhesive, thermal gap filler, thermal pad, thermal tape, phase change material, or thermal conductive coating (e.g., metal coating, diamond coating, etc.). In one or more examples, thermal interface material 404 can conform to the shape of arm 400. Further, when arm subassembly 402 (e.g., via Figure 3 When the assembly inlet 314 (shown) is inserted into the housing 302, the thermal interface material 404 can adjust, move, mold, or conform along the installation path.

[0068] like Figure 4As shown, thermal interface material 404 can be positioned above SoC 322 and PCB 320. For example, SoC 322 is sandwiched between thermal interface material 404 and PCB 320. In some examples, thermal interface material 404 encapsulates surface areas of SoC 322 that are not mounted to PCB 320 (e.g., all unmounted surfaces of SoC 322). In certain examples, thermal interface material 404 abuts (i.e., directly contacts) at least one surface of SoC 322. Additionally or alternatively, thermal interface material 404 abuts at least one surface of PCB 320. In other examples, an air gap or intervening material is positioned between thermal interface material 404 and SoC 322 or PCB 320.

[0069] Thermal interfacing material 404 may include a variety of different thicknesses. As with other components or designs, the thickness of thermal interfacing material 404 does not have to be a constant value. In practice, space and thermal tradeoffs may affect certain portions of thermal interfacing material 404 in arm assembly 402 having a greater thickness or a lesser thickness. In some examples, thermal interfacing material 404 includes a thickness of about 0.2 mm to about 1 mm. In certain examples, thermal interfacing material 404 includes a thickness of less than about 0.5 mm. For example, in a particular example, thermal interfacing material 404 includes a thickness of about 0.3 mm to about 0.5 mm.

[0070] In some examples, the arm subassembly 402 can interface with a heat spreader 406. As used herein, the term "heat spreader" refers to a material that transfers or distributes heat from a hotter source to a cooler source. In some examples, the heat spreader 406 is a thermally conductive element that disperses or diffuses thermal energy from the arm subassembly 402 across a surface area of ​​the heat spreader 406. In this manner, the heat spreader 406 can more effectively distribute the heat load across the first surface 306. For example, in one or more examples, the heat spreader 406 is lined with an interior portion of the first surface 306 such that the heat spreader 406 and the first surface 306 are in direct contact.

[0071] It should be understood that the heat spreader 406 may be lined along the interior portion of the first surface 306 at a particular time during the assembly process. For example, in some examples, the heat spreader 406 may be lined at (e.g., via Figure 3 The heat spreader 406 is applied to the interior portion of the first surface 306 before the arm subassembly 402 is inserted into the housing 302 (see the assembly inlet 314 shown). In some implementations, lining the first surface 306 with the heat spreader 406 before inserting the arm subassembly 402 can facilitate better application of the heat spreader 406 (e.g., more uniform spreading, fewer missed areas, etc.). Alternatively, the heat spreader 406 is applied to the interior portion of the first surface 306 after the arm assembly 402 is inserted into the housing 302.

[0072] One or more different components of the arm subassembly 402 can interface with the heat spreader 406. In some examples, the thermal interface material 404 interfaces with the heat spreader 406. Additionally or alternatively, at least one of the SoC 322 or the PCB 320 interfaces with the heat spreader 406. In these or other examples, the interface with the heat spreader 406 can be direct, intimate contact. Alternatively, the interface with the heat spreader 406 can be a close interface, where the heat spreader 406 and the interface element are separated by an air gap or an intervening element (e.g., an epoxy molding compound).

[0073] Heat diffuser 406 may include various materials with high thermal conductivity. Examples of heat diffuser 406 include graphite, copper, aluminum, diamond, carbon fiber (e.g., pitch carbon fiber), etc. In the example of pitch carbon fiber, it should be understood that the fiber may be oriented in one or more predetermined directions. Similarly, the fiber may include one or more oriented fiber layers. The fiber layers may have the same or different fiber orientations. In some examples, heat transfer occurs faster in the direction in which the fibers are oriented. Therefore, in some examples, the fibers of heat diffuser 406 may be oriented parallel to first surface 306 to distribute heat load more evenly across heat diffuser 406. In at least some cases, this parallel orientation of the fibers helps to avoid local hot spots on first surface 306 of housing 302.

[0074] Heat diffuser 406 may also include various thicknesses. In some examples, the thickness of heat diffuser 406 is in the range of about 10 microns to about 500 microns. In a specific example, the thickness of heat diffuser 406 may be in the range of about 50 microns to about 300 microns. In some examples, heat diffuser 406 may include a thickness of about 100 microns. The thickness of heat diffuser 406 is not limited to a constant thickness value.

[0075] Optional element 408 may include one or more components or design configurations. In some examples, element 408 includes an air gap, a heat sink, or an insulating material. Additionally or alternatively, element 408 includes a battery, a speaker, a microphone, etc. In a specific example, element 408 includes a combination of the foregoing.

[0076] Utilizing one or more of the aforementioned components, the arm 400 can implement at least one thermal path to transfer thermal energy in a direction 324 toward the ambient environment 206 and away from the user's head 101. For purposes of illustration, the arrangement of the aforementioned components of the arm 400 forms an example thermal path or heat flow. Specifically, heat is drawn from the SoC 322 and the PCB 320 to the thermal interface material 404, to the heat spreader 406, to the first surface 306, and toward the ambient environment 206.

[0077] In another example thermal path that omits heat spreader 406, heat is drawn from SoC 322 to thermal interface material 404, to first surface 306, and toward ambient environment 206. In this example thermal path, at least two of SoC 322, thermal interface material 404, or first surface 306 are in direct contact to employ natural conduction heat transfer. Additionally or alternatively, there is at least one air gap between SoC 322, thermal interface material 404, or first surface 306 (to employ non-forced convection heat transfer).

[0078] In yet another example thermal path that omits the thermal interface material 404, heat is drawn from the SoC 322 to the heat spreader 406, to the first surface 306, and toward the ambient environment 206. In this example thermal path, at least two of the SoC 322, the heat spreader 406, or the first surface 306 are in direct contact for natural thermal conduction. Alternatively, there is at least one air gap between the SoC 322, the heat spreader 406, or the first surface 306 for unforced thermal convection.

[0079] Other thermal paths are also contemplated herein. For example, heat is drawn from PCB 320 to component 408 (which may include a heat sink). Although not aligned with direction 324, this thermal path may mitigate thermal energy dissipated through second surface 308.

[0080] Figure 4 Any of the features, components, and / or parts shown (including arrangements and configurations thereof) may be included alone or in any combination in any other examples of devices, features, components, and parts shown in other figures described herein. Similarly, any of the features, components, and / or parts shown or described with reference to other figures (including arrangements and configurations thereof) may be included alone or in any combination in any other examples of devices, features, components, and parts shown in other figures described herein. Figure 4 Examples of devices, features, components and parts are shown below. Figure 5 Alternative views of an example arm are described in detail.

[0081] Figure 5 A cross-sectional top view of an example arm 500 for a head-mounted display is illustrated. The arm 500 may be similar to the one described above with respect to Figures 1 to 4 The arms 104, 106 discussed are identical or similar.

[0082] As shown, the arm 500 includes an arm subassembly 502 disposed within the housing 302. Specifically, the arm subassembly 502 is adjacent to the heat spreader 406 lining the first surface 306 of the housing 302, as described above with respect to Figure 4 The arm 500 spans between an arm tip 310 to be positioned behind a user's ear and an arm hinge 312 to be positioned at or near a user's temple 514 .

[0083] Figure 5 Additional components not previously shown in the arm subassembly 502 are also shown. For example, in addition to the thermal interface material 404, the arm subassembly 502 also includes epoxy molding compound in the epoxy molding compound layer 504a, 504b. As used herein, the term "epoxy molding compound" refers to an encapsulant material for encapsulating electronic components. Example materials of epoxy molding compound include epoxy resin, hardener or curing agent, silicon dioxide, catalyst, filler, pigment, additive, etc. In some examples, the epoxy molding compound includes a low dielectric constant over a wide temperature range. In some examples, the epoxy molding compound has low ionic conductivity over a wide frequency range and at elevated temperatures. In some examples, the epoxy molding compound has a stable dielectric constant (e.g., up to 1.8GHz).

[0084] like Figure 5 , epoxy mold compound layer 504a may encapsulate SoC 322 and other electrical components 506 mounted to PCB 320. Epoxy mold compound layer 504b may cover the bottom surface of PCB 320.

[0085] Air gaps 506a, 506b are also defined within the arm subassembly 502. For example, the spatial distance between the epoxy molding compound layer 504b and the element 508 defines the air gap 506a. Likewise, the spatial distance between the element 508 and the second surface 308 of the housing 302 defines the air gap 506b. It should be appreciated that the air gaps 506a, 506b provide insulating properties, for example, to help reduce a heat path across the second surface 308 of the housing 302 toward the user's head 101.

[0086] In some examples, the size and shape of the air gaps 506a, 506b depends on the size and shape of the element 508. For example, in the case where the element 508 is a battery, the size of the air gaps 506a, 506b can be designed to accommodate the expansion of the battery during the charging cycle. In some examples, the air gaps 506a, 506b are about 2% to about 40% of the nominal thickness of the battery. In other examples, the air gaps 506a, 506b are about 5% to about 20% of the nominal thickness of the battery. In a specific example, the air gaps 506a, 506b are about 10% of the nominal thickness of the battery.

[0087] Arm subassembly 502 also includes element 508. Element 508 may include a variety of different components. For example, element 508 includes a heat sink or a vapor chamber. Additionally or alternatively, element 508 may include a battery, a speaker, a microphone, etc. In a specific example, element 508 may include a combination of the foregoing. In the case of a heat sink, element 508 can help reduce the thermal path across the second surface 308 of the housing 302 toward the user's head 101. In the case where element 508 is a battery, air gap 506a can help protect the battery from thermal degradation. Similarly, one or more thermal paths between thermally coupled components (illustrated via cross-hatched illustrations) can draw heat away from the battery in direction 324 to help extend battery life.

[0088] In addition, arm assembly 502 may include element 510. Element 510 may similarly include a number of different components such as element 508. For example, element 510 includes a heat sink. Additionally or alternatively, element 510 may include a battery, a speaker, a microphone, etc. In a specific example, element 510 may include a combination of the foregoing.

[0089] As further shown, the arm subassembly 502 can include an insulating material 512. As used herein, the term "insulating material" refers to a material that can provide thermal resistance. In at least some examples, the insulating material 512 helps mitigate thermal convection to the second surface 308 of the housing 302. Additionally, in some examples, the insulating material provides structural support to the element 508 without (or with insignificant) thermal conductivity from the base portion 318b and the arm hinge 312.

[0090] The foregoing elements just discussed can provide a number of different thermal paths, particularly thermal paths between thermally coupled components (illustrated via cross-hatched illustrations). In doing so, the arm 500 can draw heat away from the SoC 322 and in a direction 324 toward the ambient environment 206 (opposite to the user's head 101). Similarly, the thermal paths between the thermally coupled components can spread the heat from the SoC 322 across a larger surface area of ​​the first surface 306 to enhance heat dissipation toward the ambient environment 206.

[0091] In some examples, the base portion 318a is not thermally coupled to other components. For example, the base portion 318a may be composed of a non-thermally conductive material (e.g., a polymer material), while the base portion 318b may be composed of a thermally conductive material (e.g., a metal). In this way, the base portion 318a may provide structural support to temperature-sensitive components (such as element 510). In addition, in some examples, the form factor of the housing 302 may be reduced toward the arm tip 310. Moreover, the arm tip 310 may accommodate certain temperature-sensitive components. Therefore, in some examples, the components thermally coupled to the SoC 322 may be limited to the heat spreader 406 and the first surface 306 at the portion extending toward the arm tip 310 of the arm 500.

[0092] Figure 5 Any of the features, components, and / or parts shown (including arrangements and configurations thereof) may be included alone or in any combination in any other examples of devices, features, components, and parts shown in other figures described herein. Similarly, any of the features, components, and / or parts shown or described with reference to other figures (including arrangements and configurations thereof) may be included alone or in any combination in any other examples of devices, features, components, and parts shown in other figures described herein. Figure 5 Examples of devices, features, components and parts are shown below. Figure 6 A more detailed view of an example arm configuration with a guided heat path is discussed.

[0093] Figure 6 A cross-sectional top view of an example arm 600 for a head-mounted display is illustrated. The arm 600 may be similar to the one described above with respect to Figures 1 to 5 The arms 104, 106 discussed are identical or similar.

[0094] The arm 600 includes a specific exemplary arrangement of components within the scope of the present disclosure for dissipating heat in the direction 324 toward the ambient environment 206. As shown, the arm 600 includes a metal base portion 602 and a plastic base portion 604. The metal base portion 602 is attached to an inner portion of the first surface 306 of the housing 302 at a joint 606.

[0095] The arm 600 also includes a hinge connection 608 extending from the metal base portion 602. The hinge connection 608 and the hinge assembly 610 work together to provide a rotatable hinge joint for the arm 600 so that the arm 600 can be moved relative to the display 102 ( Figure 1 to Figure 2 608) rotates between an open position and a closed position. Disposed within the hinge connector 608 is a cable bundle 612 that passes through a cable channel defined by an inner wall of the hinge connector 608. According to one example, some heat or thermal energy can flow through the metal base portion 602, through the hinge assembly 610, and to other portions of the head mountable display to be dissipated away from the user.

[0096] In addition, the arm 600 includes a battery 614. The battery 614 may be positioned between the PCB 320 and the second surface 308. In addition to the power connection between the battery 614 and the PCB 320, an air gap surrounds the battery 614.

[0097] In addition, the arm 600 includes a speaker 616. The speaker 616 can be positioned near the arm tip 310 of the arm 600.

[0098] It should be appreciated that one or more of the thermal paths discussed above may be implemented in the arm 600. Specifically, heat from the SoC 322 in the arm 600 may be dissipated through the air gap above the SoC 322, through the first surface 306, and toward the ambient environment 206. Other thermal paths discussed above may also be implemented in the arm 600. For example, one or more thermal paths draw heat away from the battery 614 to improve battery life.

[0099] Figure 6 Any of the features, components, and / or parts shown (including their arrangements and configurations) may be included alone or in any combination in any other examples of devices, features, components, and parts shown in other figures described herein. Similarly, any of the features, components, and / or parts shown or described with reference to other figures (including their arrangements and configurations) may be included alone or in any combination in any other examples of devices, features, components, and parts shown in other figures described herein. Figure 6 Examples of devices, features, components and parts are shown below. Figure 7 Examples of heat dissipation results achieved using the present configuration are described in detail.

[0100] Figure 7 The experimental results of implementing a thermal path during a test operation according to one or more examples of the present disclosure are illustrated. During the experiment, the experimenter operated the worn head-mounted display and measured the surface temperature of the arm of the head-mounted display. The measured surfaces include a first surface 306 (i.e., an external, world-facing surface) and a second surface 308 (i.e., an internal, user-facing surface), both of which are discussed above.

[0101] Specifically, Figure 7 A graph 700 is illustrated, wherein the X-axis is defined as a function of “time” and the Y-axis is defined as a function of “temperature.” Among other things, the graph 700 includes a curve 702 indicating a temperature for the first surface 306. Furthermore, the graph 700 includes a curve 704 indicating a temperature for the second surface 308.

[0102] As evidenced by the graph 700, over time (i.e., as the head mountable display performs operations), the temperature of both the first surface 306 and the second surface 308 increases. However, the curves 702, 704 indicate that more of the heat load is dissipated through the first surface 306 than the second surface 308. That is, the second surface 308 adjacent to the user's head 101 remains cooler during operation of the head mountable display than the first surface 306, thereby increasing the comfort experienced by the user.

[0103] In some examples, the present systems and methods may collect and use data available from various sources that may be used to improve the delivery of invitation content or any other content that may be of interest to the user. In some examples, the collected data may include personal information data. The use of such personal information data should be collected, analyzed, disclosed, transmitted, stored, or otherwise used in accordance with well-established privacy policies and / or privacy practices and for lawful and reasonable purposes.

[0104] Although the specification includes specific nomenclature to provide a thorough understanding of the described embodiments, it will be apparent to those skilled in the art that these specific details are not required in order to practice the described embodiments. On the contrary, the foregoing descriptions of the specific embodiments described herein are presented for purposes of illustration and description and are not intended to be exhaustive or to limit the embodiments to the precise forms disclosed, and it will be apparent to those of ordinary skill in the art that many modifications and variations are possible in light of the above teachings.

Claims

1. An arm for a head-mounted display, comprising: Arm hinge; a housing connected to the arm hinge, the housing including a first surface and a second surface opposite the first surface, the housing defining an arm tip and an interior volume spanning between the arm tip and the arm hinge; a printed circuit board (PCB), the PCB positioned within the interior volume; a heat source attached to the PCB; a thermal interface material and a heat diffuser material disposed between the heat source and the first surface; as well as A thermal path is directed from the heat source, through the thermal interface material, through the heat spreader material, through the first surface, and toward an ambient environment.

2. The arm of the head-mountable display according to claim 1, further comprising: a base connecting the PCB to the arm hinge; as well as An additional heat path is directed from the heat source, through the PCB, through the base, through the arm hinge, and toward the ambient environment.

3. The arm of the head mountable display according to claim 1, further comprising a heat sink positioned between the PCB and the second surface; Wherein the heat sink and the PCB define an air gap within the interior volume.

4. The head mountable display arm of claim 3, further comprising an additional heat path directed from the heat source through the PCB, through the air gap, and to the heat sink. 5 . The head mountable display arm of claim 1 , wherein the heat source is positioned closer to the first surface than to the second surface.

6. The head mountable display arm of claim 1, wherein the heat source is oriented toward the first surface.

7. The arm of a head-mountable display according to claim 1, further comprising a battery positioned between the PCB and the second surface, wherein the PCB, the battery and the second surface are spatially separated by corresponding air gaps.

8. A head-mounted device comprising: monitor; an arm housing connected to the display, the arm housing including a heat dissipation surface oriented toward the surrounding environment; as well as An arm subassembly, the arm subassembly being arranged in the arm housing, the arm subassembly comprising: Base; a printed circuit board (PCB), the PCB attached to the base; and a system on a chip (SoC) mounted to the PCB and oriented toward the heat dissipation surface; an arm hinge connected to the arm subassembly; and A conductive path is provided from the SoC, through the PCB, and through the arm hinge.

9. The head mountable device according to claim 8, wherein the arm housing comprises: A unitary housing is connected to the arm hinge, the unitary housing defining an arm tip and an interior volume between the arm tip and the arm hinge.

10. The head mountable device of claim 9, wherein the arm housing defines a component access into the interior volume, the component access being positioned proximate to the arm hinge.

11. The head mountable device of claim 8, wherein the heat dissipation surface inside the arm housing comprises a thermal lining adjacent to the arm subassembly.

12. The head mountable device of claim 11, wherein the thermal lining draws heat away from the arm subassembly and toward the heat dissipation surface.

13. The head mountable device of claim 8, wherein the arm subassembly further comprises a thermal insulator disposed between the PCB and a surface of the arm housing opposite to the heat dissipation surface.

14. The head mountable device of claim 8, wherein the arm subassembly further comprises a thermal interface material and an epoxy molding compound.

15. A heat flow device for an augmented reality glasses arm, the heat flow device comprising: Printed circuit board (PCB); a heat source attached to the PCB; a heat dissipation surface oriented toward the surrounding environment, the heat dissipation surface extending from a proximal end to a distal end of the augmented reality glasses arm; as well as A heat spreader material is disposed adjacent to the heat source, the heat spreader material lining an interior portion of the heat dissipation surface between the proximal and distal ends.

16. The thermal flow device according to claim 15, further comprising: A thermal interface material is positioned between the heat spreader material and the heat source.

17. The heat flow device of claim 16, wherein at least one of the thermal interface material or the heat spreader material conducts thermal energy away from the heat source and to a surrounding environment via at least one of natural conduction or unforced convection.

18. The thermal flow device according to claim 15, The heat diffuser material includes at least one of a pitch-based carbon fiber material, a graphite material, or a copper material.

19. The heat flow device of claim 18, further comprising an insulator disposed adjacent to the heat source opposite the heat spreader material.

20. The thermal flow device according to claim 15, Wherein the heat spreader material spreads the heat load from the heat source onto the heat dissipation surface.

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