Thermal Management System for Portable Electronic Devices - Patent application

Abstract

To provide a thermal management system for a portable electronic device.SOLUTION: A wearable electronic device is disclosed. The device can include a support structure, and an electronic component disposed in or on the support structure. A heat exchanger element can be thermally coupled to the electronic component, and the heat exchanger element includes a fluid inlet port and a fluid outlet port. A first conduit can be fluidly connected to the fluid inlet port of the heat exchanger, and the first conduit is configured to transmit liquid to the heat exchanger at a first temperature. A second conduit can be fluidly connected to the fluid outlet port of the heat exchanger, and the second conduit is configured to transmit liquid at a second temperature different from the first temperature so as to be away from the heat exchanger.SELECTED DRAWING: None

Description

[Technical field]

[0001] (Priority Claim) This application claims the benefit of priority under 35 U.S.C. § 119(e) to U.S. Provisional Application No. 62 / 853,613, filed May 28, 2019. The entire disclosure of each of these priority documents is incorporated herein by reference.

[0002] The present invention relates to thermal management systems for portable electronic devices. [Background technology]

[0003] In various types of portable electronic devices, it can be difficult to adequately dissipate heat generated by on-board electronics, power supplies (e.g., batteries), or other electronic components that act as heat sources. It can be desirable to improve the dissipation of heat within electronic devices.

[0004] For example, in some embodiments, modern computing and display technology has facilitated the development of systems for virtual reality and / or augmented reality experiences, where digitally reproduced images or portions thereof are presented to a user in a manner in which they appear or may be perceived as being real. Virtual reality, or "VR", scenarios typically involve the presentation of digital or virtual image information without transparency to other actual real-world visual input, while augmented reality, or "AR", scenarios typically involve the presentation of digital or virtual image information as an extension to the visualization of the real world around the user.

[0005] Some VR or AR systems may include portable electronic devices that may be subject to thermal loads that may be uncomfortable for the user or that may damage components of the system. Thus, there remains a continuing need for improved thermal solutions for portable (e.g., wearable) electronic devices, including those used in conjunction with VR or AR systems. Summary of the Invention [Means for solving the problem]

[0006] Various embodiments disclosed herein relate to thermal management systems for wearable or portable electronic devices, such as for wearable VR or AR systems. Various types of wearable electronic devices include processors and other components that generate heat. Such heat generation can increase the temperature of the electronic device, which can cause discomfort to a user and / or can adversely affect the operation of the electronic device. Various embodiments disclosed herein include thermal management systems that include a liquid cooling apparatus, including liquid conduits, and a heat exchanger configured to remove heat from the device to improve the user experience and / or device operation.

[0007] In one embodiment, a wearable electronic device is disclosed. The wearable electronic device may include a support structure. The wearable electronic device may include an electronic component disposed in or on the support structure. The wearable electronic device may include a heat exchanger element thermally coupled to the electronic component, the heat exchanger element including a fluid inlet port and a fluid outlet port. The wearable electronic device may include a first conduit fluidly connected to the fluid inlet port of the heat exchanger, the first conduit configured to transfer a liquid at a first temperature to the heat exchanger. The wearable electronic device may include a second conduit fluidly connected to the fluid outlet port of the heat exchanger, the second conduit configured to transfer a liquid at a second temperature different from the first temperature away from the heat exchanger.

[0008] In another embodiment, a cooling system for a portable device is disclosed. The cooling system can include a heat generating element and a heat transfer system. The heat transfer system can include a heat exchanger disposed adjacent to the heat generating element, a radiator, a fan disposed adjacent to the radiator, a heat transfer circuit in fluid communication with the heat exchanger and the radiator, and a pump in fluid communication with the heat transfer circuit. The cooling system can include a motor having an output shaft coupled to at least one of the fan and the pump.

[0009] Details of one or more implementations of the subject matter described herein are set forth in the accompanying drawings and the description below. Other features, aspects, and advantages will become apparent from the description, drawings, and claims. Neither this summary nor the following detailed description purports to define or limit the scope of the inventive subject matter. The present invention provides, for example, the following: (Item 1) A wearable electronic device, comprising: A support structure; an electronic component disposed within or on the support structure; a heat exchanger element thermally coupled to the electronic component, the heat exchanger element including a fluid inlet port and a fluid outlet port; a first conduit fluidly connected to a fluid inlet port of the heat exchanger, the first conduit configured to transfer a liquid at a first temperature to the heat exchanger; a second conduit fluidly connected to a fluid outlet port of the heat exchanger, the second conduit configured to convey a liquid at a second temperature, different from the first temperature, away from the heat exchanger; A wearable electronic device comprising: (Item 2) 2. The wearable electronic device of claim 1, further comprising a pump in fluid communication with the first conduit and / or the second conduit. (Item 3) Item 3. The wearable electronic device of item 2, wherein the pump comprises a regenerative pump. (Item 4) 3. The wearable electronic device of claim 2, wherein the pump comprises at least one of a piezoelectric pump and a centrifugal pump. (Item 5) 5. The wearable electronic device of any one of claims 2-4, further comprising a motor configured to drive the pump. (Item 6) Item 6. The wearable electronic device of item 5, wherein the motor comprises a pancake motor. (Item 7) 7. The wearable electronic device of any one of claims 1-6, wherein the liquid comprises water and propylene glycol. (Item 8) 8. The wearable electronic device of any one of claims 1-7, further comprising an accumulator configured to reduce the amount of air in the liquid. (Item 9) 9. The wearable electronic device of claim 8, wherein the accumulator comprises a container configured to hold at least a portion of the liquid thermally conductive medium and a closure device configured to remain at a top level of the liquid thermally conductive medium regardless of the volume of the thermally conductive medium. (Item 10) 10. The wearable electronic device of claim 9, wherein the accumulator comprises a pressure regulator. (Item 11) 10. The wearable electronic device of claim 9, wherein the accumulator comprises a pressure chamber. (Item 12) 10. The wearable electronic device of item 9, further comprising a spring coupled to the closure device to maintain the closure device at a top level of the liquid thermally conductive medium. (Item 13) The wearable electronic device according to any one of claims 1 to 12, further comprising a radiator in fluid communication with the first conduit or the second conduit, the radiator having fins such that heat in the liquid is conducted from the liquid to the radiator and heat in the radiator is conducted from the radiator to air surrounding the radiator. Item 14. The wearable electronic device of item 13, further comprising a one-way valve in fluid communication with the accumulator. (Item 15) the electronic component is a first electronic component, the heat exchanger is a first heat exchanger, and the wearable electronic device further comprises: a second electronic component; and A second heat exchanger; a third conduit, the third conduit fluidly connected to a fluid inlet port of the second heat exchanger, the third conduit configured to transfer a liquid at a third temperature to the second heat exchanger; a fourth conduit fluidly connected to a fluid outlet port of the second heat exchanger, the fourth conduit configured to convey a liquid at a fourth temperature, different from the third temperature, away from the second heat exchanger; Item 15. The wearable electronic device of any one of items 1-14, comprising: (Item 16) Item 16. The wearable electronic device of item 15, wherein the first and second conduits are fluidly connected to first and second ports of a radiator, and the third and fourth conduits are fluidly connected to third and fourth ports of the radiator. (Item 17) Item 16. The wearable electronic device of item 15, wherein the third conduit provides fluid communication between a fluid inlet port of the second heat exchanger and a second fluid outlet port of the first heat exchanger. (Item 18) Item 18. The wearable electronic device of item 17, wherein the fourth conduit provides fluid communication between a fluid outlet port of the second heat exchanger and a second fluid inlet port of the first heat exchanger. (Item 19) 19. The wearable electronic device of any one of items 17-18, further comprising a fifth conduit extending between a second fluid outlet port of the second heat exchanger and a second fluid inlet port of the second heat exchanger. (Item 20) 20. The wearable electronic device of any one of claims 1-19, wherein the first and second conduits extend between the first heat exchanger and a radiator. (Item 21) 1. A cooling system for a portable device, comprising: A heat generating element; 1. A heat transfer system comprising: a heat exchanger disposed adjacent to the heat generating element; A radiator, a fan disposed adjacent to the radiator; a heat transfer circuit in fluid communication with the heat exchanger and the radiator; a pump in fluid communication with the heat transfer circuit; a heat transfer system comprising: a motor having an output shaft coupled to at least one of the fan and the pump; A cooling system comprising: (Item 22) 22. The cooling system of claim 21, wherein the output shaft of the motor is coupled to the fan and the pump and rotates the fan to generate airflow across the radiator and simultaneously rotates the pump to move liquid through the heat exchanger and the radiator. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 depicts an illustration of an augmented reality scenario involving a virtual reality object and a physical object viewed by a person.

[0011] [Figure 2A] 2A-2D diagrammatically illustrate an example of a wearable system, according to various embodiments. [Figure 2B] 2A-2D diagrammatically illustrate an example of a wearable system, according to various embodiments. [Figure 2C] 2A-2D diagrammatically illustrate an example of a wearable system, according to various embodiments. [Figure 2D] 2A-2D diagrammatically illustrate an example of a wearable system, according to various embodiments.

[0012] [Figure 3A] 3A-3C illustrate head-mounted components and local processing and data modules, according to various embodiments. [Figure 3B] 3A-3C illustrate head-mounted components and local processing and data modules, according to various embodiments. [Figure 3C] 3A-3C illustrate head-mounted components and local processing and data modules, according to various embodiments.

[0013] [Figure 4] FIG. 4 is a schematic system view of a thermal management system, according to one embodiment.

[0014] [Diagram 5] FIG. 5 is a schematic system view of a thermal management system according to another embodiment.

[0015] [Figure 6] FIG. 6 is a schematic diagram of the accumulator shown in FIG.

[0016] [Figure 7]FIG. 7 is a schematic diagram showing a portion of a thermal management system that is used to fill the system with a cooling liquid, according to various embodiments.

[0017] Throughout the drawings, reference numbers may be reused to indicate correspondence between referenced elements. The drawings are provided to illustrate example embodiments described herein and are not intended to limit the scope of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Various embodiments disclosed herein relate to portable (e.g., wearable) electronic devices. For example, in FIG. 1, an augmented reality scene 4 is depicted in which a user of the AR technology sees a real-world park-like setting 6 featuring people, trees, buildings in the background, and a concrete platform 1120. In addition to these items, the user of the AR technology also perceives that he or she "sees" a robotic figure 1110 standing on the real-world platform 1120 and a flying cartoon-like avatar character 2 that appears to be an anthropomorphic bumblebee, although these elements 2, 1110 do not exist in the real world. At least the elements 2, 1110 can be provided to the user, at least in part, by the portable (e.g., wearable) electronic device disclosed herein. In conclusion, the human visual perception system is very complex, making it difficult to produce VR or AR technology that promotes a comfortable, natural-feeling, and rich presentation of virtual image elements among other virtual or real-world image elements.

[0019] For example, a head-mounted AR display (or helmet-mounted display or smart glasses) is typically at least loosely coupled to a user's head and may therefore move as the user's head moves. When movement of the user's head is detected by the display system, the displayed data can be updated to account for the change in head pose.

[0020] As an example, when a user wearing a head mounted display views a virtual representation of a three-dimensional (3-D) object on the display and walks around the area in which the 3-D object appears, the 3-D object can be re-rendered for each viewpoint, giving the user the perception that they are walking around objects that occupy real space. When a head mounted display is used to present multiple objects (e.g., a rich virtual world) in a virtual space, measurements of head pose (e.g., the location and orientation of the user's head) can be used to re-render the scene to match the user's dynamically changing head location and orientation, providing an increased sense of immersion in the virtual space.

[0021] In an AR system, head pose detection or calculation can facilitate the display system rendering virtual objects so that they appear to occupy space in the real world in a manner that makes sense to the user. In addition, detection of the position and / or orientation of a real object, such as a handheld device (which may also be referred to as a "totem"), a tactile device, or other real physical object in conjunction with the user's head or the AR system, can also facilitate the display system presenting display information to the user and allowing the user to effectively interact with certain aspects of the AR system. As the user's head moves around in the real world, virtual objects can be re-rendered as a function of head pose so that the virtual objects appear to remain stable relative to the real world. At least for AR applications, placement of virtual objects in spatial conjunction with physical objects (e.g., presented to appear spatially proximate to the physical objects in two or three dimensions) may not be a trivial issue. For example, head movement can significantly complicate placement of virtual objects from the perspective of the surrounding environment. This applies whether the viewpoint is captured as an image of the surrounding environment and then projected or displayed to the end user, or whether the end user directly perceives the viewpoint of the surrounding environment. For example, head movement is likely to change the end user's field of view, which will likely require updates to where various virtual objects are displayed in the end user's field of view. In addition, head movements may occur in a wide variety of ranges and speeds. Head movement speed may vary not only between different head movements, but also within or across the range of a single head movement. For example, head movement speed may initially increase (e.g., linearly or nonlinearly) from a starting point, decrease as an end point is reached, and obtain a maximum speed at some location between the start and end points of the head movement. High speed head movements may exceed the capabilities of even a particular display or projection technology, rendering an image that appears to the end user as uniform and / or smooth motion.

[0022] Head tracking accuracy and latency (e.g., the time that elapses between when a user moves their head and when an image is updated and displayed to the user) are challenges for VR and AR systems. In particular, for display systems that fill a substantial portion of the user's field of view with virtual elements, it is advantageous if the head tracking accuracy is high and the overall system latency from the initial detection of head movement to the update of the light delivered by the display to the user's visual system is very low. If the latency is high, the system may create a user perception scenario that introduces a mismatch between the user's vestibular and visual sensory systems, leading to motion sickness or 3D sickness. If the system latency is high, the apparent location of virtual objects may appear unstable during fast head movements.

[0023] In addition to head-mounted display systems, other display systems can also benefit from accurate and low-latency head pose detection. These include head-tracked display systems, where the display is not attached to the user's body, but is mounted, for example, on a wall or other surface. The head-tracked display can act like a window onto a scene, and as the user moves their head relative to the "window," the scene is re-rendered to match the user's changing viewpoint. Other systems include head-mounted projection systems, where the head-mounted display projects light onto the real world.

[0024] In addition, the AR system may be designed to interact with the user to provide a realistic augmented reality experience. For example, multiple users may play a ball game with a virtual ball and / or other virtual objects. One user may "catch" the virtual ball and throw it back to another user. In another embodiment, a first user may be provided with a totem (e.g., an actual bat communicatively coupled to the AR system) to hit the virtual ball. In other embodiments, a virtual user interface may be presented to the AR user to allow the user to select one of many options. The user may use a totem, a tactile device, a wearable component, or simply touch a virtual screen and interact with the system.

[0025] Detecting the pose and orientation of a user's head, and the physical location of real objects in space, allows an AR system to display virtual content in an effective and enjoyable manner. However, these capabilities, while important for an AR system, are difficult to achieve. In other words, an AR system must recognize the physical location of real objects (e.g., the user's head, a totem, a tactile device, a wearable component, the user's hand, etc.) and correlate the physical coordinates of the real objects to virtual coordinates corresponding to one or more virtual objects displayed to the user. This generally requires highly accurate sensors and sensor recognition systems that track the position and orientation of one or more objects at a fast rate. Current approaches do not perform localization at a satisfactory speed or accuracy standard.

[0026] Thus, there is a need for better localization systems in the context of AR and VR devices. Furthermore, the sustained and / or high speed movement of a user may introduce various other problems into the electrical, thermal, and / or mechanical systems of such AR and / or VR devices. In addition, the use of processors and other heat-generating components may be uncomfortable for the user or may otherwise reduce the performance of the system. For example, the processor and other heat sources may be located within a headset close to the user's skin, which may create discomfort for the user during operation of the system. Thus, it may be important to provide improved thermal management systems for AR and VR devices.

[0027] 2A-2D, several general component options are illustrated. In the detailed description section that follows the discussion of FIGs. 2A-2D, various systems, subsystems, and components are presented to address the objective of providing a high quality and comfortable perceived display system for human VR and / or AR.

[0028] As shown in FIG. 2A, an AR system user 60 is depicted wearing a head-mounted component 58 featuring a frame 64 structure coupled to a display system 62 positioned in front of the user's eyes. A speaker 66 is coupled to the frame 64 in the depicted configuration and positioned adjacent to the user's ear canal (in one embodiment, another speaker, not shown, is positioned adjacent to the user's other ear canal to provide stereo / shapeable sound control). The display 62 is operably coupled 68, such as by wired leads or wireless connectivity, to a local processing and data module 70, which may be mounted in a variety of configurations, such as fixedly attached to the frame 64, fixedly attached to a helmet or hat 80 as shown in the embodiment of FIG. 2B, built into headphones, removably attached to a torso 82 of the user 60 in a backpack-style configuration as shown in the embodiment of FIG. 2C, or removably attached to a waist 84 of the user 60 in a belt-style configuration as shown in the embodiment of FIG. 2D.

[0029] The local processing and data module 70 may comprise a power efficient processor or controller and digital memory, such as flash memory, both of which may be utilized to aid in the processing, caching, and storage of a) data captured from sensors, such as image capture devices (such as cameras), microphones, inertial measurement units, accelerometers, compasses, GPS units, wireless devices, and / or gyroscopes, which may be operatively coupled to the frame 64, and / or b) data that may be obtained and / or processed using the remote processing module 72 and / or remote data repository 74, possibly for processing or retrieval and subsequent passage to the display 62. The local processing and data module 70 may be operatively coupled 76, 78 to the remote processing module 72 and remote data repository 74, such as via wired or wireless communication links, such that the remote modules 72, 74 are operatively coupled to each other and available as resources to the local processing and data module 70.

[0030] In one embodiment, remote processing module 72 may comprise one or more relatively powerful processors or controllers configured to analyze and process data and / or image information. In one embodiment, remote data repository 74 may comprise a relatively large digital data storage facility, which may be available through the Internet or other networking configurations in a "cloud" resource configuration. In one embodiment, all data may be stored and all calculations may be performed in the local processing and data module, allowing for fully autonomous use from any remote module.

[0031] 3A and 3B illustrate one embodiment of the head-mounted component 58A and the local processing and data module 70. FIG. 3A also illustrates a handheld controller 71 configured to operate the system during an AR or VR experience. FIG. 3C is a schematic perspective cross-sectional view of the component 58A shown in FIG. 3B. Unless otherwise noted, the features of FIG. 3A may be identical to or generally similar to similarly numbered components of FIGS. 1-2D. The device shown in FIGS. 3A-3B illustrates the Magic Leap One system, sold by Magic Leap, Inc. (Planation, Florida). However, the embodiments disclosed herein can be used with any type of portable (e.g., wearable) electronic device. The frame 64A of the head-mounted component 58A may be part of a support structure 101. The support structure 101 may include one or more cavities 59 therein. Various types of electronic components, power supplies, and other devices may be mounted on or within the support structure 101, for example, within one or more cavities 59. As described herein, these devices on or within the support structure 101 may generate heat, e.g., act as a heat source. The heat generated by these devices may be uncomfortable for a user or may otherwise adversely affect the operation of the system. Thus, there remains a continuing need for improved heat dissipation techniques for the head-mounted components 58A. Similarly, in various embodiments, the electronic components of the local processing and data module 70 may also generate heat, which may be uncomfortable for a user or may otherwise adversely affect the operation of the system. The embodiments disclosed herein may thus be used to improve heat dissipation within the head-mounted components 58A, the local processing and data module 70, or both. Indeed, the embodiments disclosed herein may be used for any suitable type of portable (e.g., wearable) electronic device. (Example of a thermal management system)

[0032] 4 is a schematic system view of a thermal management system 100, according to one embodiment. The thermal management system 100 can be disposed in or on the support structure 101 of the head-mounted component 58 or 58A. For example, in some embodiments, the thermal management system 100 can be disposed in one or more cavities 59 of the enclosure 101. In other embodiments, the thermal management system 100 can be disposed in or on the local processing and data module 70, in or on the handheld controller 71, and / or on any other suitable type of portable (e.g., wearable) electronic device. As discussed above, various heat sources (electronic components 102a, 102b, etc.) can be disposed in or on the support structure 101, for example, in one or more cavities 59. The electronic components 102a, 102b generate heat, which can cause user discomfort or otherwise adversely affect system performance. The electronic components 102a, 102b can be any type of component or device that generates heat. For example, the electronic components 102a, 102b may comprise a processor, an optical emitter (e.g., a light emitting diode, or LED), a projector, a power supply, or any other type of component that generates heat. Although two electronic components 102a, 102b are shown in FIG. 4, it should be understood that any number of electronic components may be coupled to the support structure 101.

[0033] To transfer heat away from the electronic components 102a, 102b, the electronic components 102a, 102b can be thermally coupled with corresponding first and second heat exchanger elements 103a, 103b. For example, the electronic component 102a can be thermally attached to the first heat exchanger element 103a using a thermally conductive medium such as a thermal adhesive (e.g., a thermal interface material, or TIM). The electronic component 102b can be thermally attached to the second heat exchanger element 103b using a thermally conductive medium (such as a TIM). The first and second heat exchangers 103a, 103b can include a cavity structure or chamber configured to conduct heat from the electronic components 102a, 102b to a liquid cooling system that transfers heat away from the electronic components 102a, 102b and the heat exchangers 103a, 103b. For example, in various embodiments, the first and second heat exchangers 103a, 103b may include internal geometries, such as wound channels, cavities, or pins, configured to increase or maximize the area of ​​heat transfer between the fluids.

[0034] As shown in FIG. 4, the first and second heat exchangers 103a, 103b can be in fluid communication with a heat-collecting radiator 106 configured to dissipate thermal energy collected by the heat exchangers 103a, 103b to an outside environment (e.g., ambient air). In some embodiments, the heat-collecting radiator 106 can be positioned on the support structure 101 such that, when worn, it is located at or near the back side of the user's head. The first conduit 104a can fluidly connect the first fluid inlet port 105a of the first heat exchanger 103a to a corresponding first port 114a of the heat-collecting radiator 106. The conduits 104a, 104b can be disposed in or on the enclosure 101, for example, in one or more cavities 59, in some embodiments. In other embodiments, the conduits 104a, 104b can be at least partially exposed to the outside environment. The second conduit 104b can fluidly connect the first fluid outlet port 105b of the first heat exchanger 103a to a corresponding second port 114b of the thermal collector radiator 106. The third conduit 104c can fluidly connect the first fluid inlet port 105c of the second heat exchanger 103b to a corresponding third port 114c of the thermal collector radiator 106. The fourth conduit 104d can fluidly connect the first fluid outlet port 105d of the second heat exchanger 103b to a corresponding fourth port 114d of the thermal collector radiator 106.

[0035] The heat-collecting radiator 106 may comprise an internal pipe or conduit configured to conduct the collected heat from the first and second heat exchanger elements 103a, 103b to an outside environment, e.g., air. For example, the heat-collecting radiator 106 may comprise a number of pins or fins 115 that increase the surface area exposed to the air, thereby improving heat dissipation to the outside environment (e.g., using openings in the support structure 101). The heat-collecting radiator 106 may also include a fill port 107a and a vent 107b. The heat-collecting radiator 106 may be filled with a cooling fluid or coolant by supplying the cooling fluid to the fill port 107a. The vent 107b (which may comprise a one-way vent in some embodiments) may be configured to allow air to escape from the heat-collecting radiator 106 during filling. After the radiator 106 is filled with cooling fluid, the fill port 107a and the vent 107b can be sealed or otherwise closed. As discussed below in connection with FIGS. 5-6 , accumulators can also be provided along the fluid paths of the system to prevent gas or bubbles from forming in the cooling liquid. In some embodiments, a fan 116 can be provided to accelerate airflow across the fins 115 to improve heat dissipation away from the heat collecting radiator 106. In various embodiments, the fan 116 can be provided in or on the enclosure 101, for example, in one or more cavities 59. In some embodiments, air can flow through an intake port into the cavity 59 and transfer heat away from the components through an outlet port. In other embodiments, a fan may not be provided in the thermal management system 100. In some embodiments, the heat collecting radiator 106 or portions thereof (e.g., the fins 115 of the radiator 106) can be oriented away from the user's body (e.g., away from the user's head) so that heat can be conducted away from the user. In various embodiments, the fins 115 can be exposed to ambient air to enhance cooling.In some embodiments, the portion of the thermal management system opposite the fins 115 , such as the support block 119 , can be selected to insulate the user's body from the heat collected by the radiator 106 .

[0036] Additionally, a pump and a motor driving the pump may also be provided (not shown in FIG. 4), as described and illustrated below in connection with FIG. 6. The motor may be activated by suitable electronics to drive the pump, which in turn may drive the liquid through the conduits 104a-104d and the heat exchanger elements 103a, 103b. In some embodiments, the output shaft of the motor may be coupled to the fan 116 and the pump to rotate the fan 116 to generate airflow across the radiator 106 and simultaneously rotate the pump to move the liquid through the heat exchanger 103a or 103b and the radiator 106. In some embodiments, a clutch or switching mechanism may be provided such that the system may drive the fan 116 and the pump separately when the fan 116 and the pump share a common motor shaft and motor. In some embodiments, the fan 116 and the pump may each have an associated motor to drive the fan 116 and the pump separately. Additionally, in some embodiments, the radiator 106 may include an active cooling sink, such as active or forced airflow, over an extended surface area (eg, fins or pins).

[0037] The thermal management system 100 shown in FIG. 4 is an example of a balanced thermal system. For example, as shown in FIG. 4, a first thermal path 117a (e.g., including conduits 104a, 104b) can transfer heat from a first heat exchanger element 103a to a heat collecting radiator 106. A second thermal path 117b (e.g., including conduits 104c, 104d) can transfer heat from a second heat exchanger element 103b to a heat collecting radiator 106. In FIG. 4, the first and second thermal paths 117a, 117b are at least partially, and in some cases, completely, thermally independent or isolated from each other. The path 117b can be at least independent from the path 117a between the radiator 106 and the heat exchanger element to which it and each of them are respectively coupled. This can provide the advantage of allowing the amount of heat to be removed from each electronic component 102a, 102b to be addressed independently. For example, in FIG. 4, the amount of heat collected by the first heat exchanger element 103a and conducted to the radiator 106 may be independent of the amount of heat collected by the second heat exchanger element 103b and conducted to the radiator 106.

[0038] During operation, a pump (not shown in FIG. 4, see FIG. 5) can drive a liquid (e.g., a coolant) within the thermal management system 100 along a first conduit 104a to a first heat exchanger element 103a via a first fluid inlet 105a. The liquid can be routed within the first heat exchanger element 103a to a second conduit 104b via a first fluid outlet 105a (and any additional conduits or tubing within the first heat exchanger element 103a). Thus, a cold, i.e., cryogenic, liquid can be supplied at a first temperature to the first heat exchanger element 103a along the first conduit 104a. Heat generated by the electronic component 102a (which can act as a heat source) can increase the temperature of the liquid to a second temperature above the first temperature. It should be understood that while the heat source in FIG. 4 includes electronic components 102a, in other embodiments the heat source can comprise any other suitable device or system that generates unwanted thermal energy. The resulting warm, i.e., hot, liquid at the second temperature can be transferred along the second conduit 104b away from the first heat exchanger element 103a to the heat collector radiator 106. The cooling liquid can comprise any suitable type of coolant, including, for example, a solution comprising water and propylene glycol. The pump in the thermal management system 100 can be integrated, either physically or functionally, into the heat collector radiator 106. For example, the pump can be housed in the support block 119 in one embodiment, or can be housed separately, as illustrated in connection with the system 200 discussed below.

[0039] Similarly, the pump discussed above (or another pump) can drive a liquid (e.g., a coolant) along the third conduit 104c to the second heat exchanger element 103b via the fluid inlet 105c of the second heat exchanger element 103b. The liquid can be routed within the second heat exchanger element 103b to the fourth conduit 104d via the fluid outlet 105d (and any additional conduits or tubing within the second heat exchanger element 103b). Thus, a cold, i.e., cryogenic, liquid at a first temperature can be supplied along the third conduit 104c to the second heat exchanger element 103b. Heat generated by the electronic component 102b (which can act as a heat source) can increase the temperature of the liquid to a second temperature above the first temperature. The resulting warm, or hot, liquid at the second temperature can be conducted away from the second heat exchanger element 103b and along the fourth conduit 104d to the heat collecting radiator 106.

[0040] Warm or hot liquid at a second temperature may pass through one or more conduits in the thermal collecting radiator 106. Thermal energy from the warm or hot liquid may be conducted to and from the fins 115 of the radiator 106 to the air. As discussed above, in some embodiments, the fan 116 may enhance the dissipation of heat from the fins 115 by accelerating the airflow across the fins 115.

[0041] Beneficially, the thermal management system 100 shown in FIG. 4 can substantially reduce temperatures to maintain user comfort and system performance. For example, the thermal management system 100 can maintain the surface temperature of the head-mounted components 58, 58A at a level below a predetermined maximum temperature threshold. In some embodiments, the surface temperature of the head-mounted components 58, 58A can be maintained at least 10° C. below the predetermined maximum temperature threshold. In some embodiments, the surface temperature of the head-mounted components 58, 58A can be maintained at least 12° C. below the predetermined maximum temperature threshold. In some embodiments, the surface temperature of the head-mounted components 58, 58A can be maintained at least 18° C. below the predetermined maximum temperature threshold, for example, when the system 100 includes a fan to improve heat dissipation. Thus, in various embodiments, the surface temperature of the head-mounted components 58, 58A can be maintained at a temperature within a range of 10° C. to 25° C. below the predetermined maximum threshold temperature. In some embodiments, the thermal management system 100 can reduce the temperature to a temperature slightly above ambient temperature, for example, 1° C. to 5° C. above ambient temperature (e.g., room temperature). In various embodiments, the thermal management system 100 can be configured to dissipate approximately equal thermal energy to the thermal energy produced by the heat-generating components (components 102a, 102b, etc.) such that the thermal loop is close to or nearly energy neutral.

[0042] Moreover, the thermal management system 100 can advantageously be provided in a small form factor suitable for use in portable (eg, wearable) electronic devices.

[0043] Figure 5 is a schematic system view of a thermal management system 200 according to another embodiment. Unless otherwise noted, the components of Figure 5 may generally be similar to or identical to similarly numbered components of Figure 4, with reference numbers incremented by 100 relative to the reference numbers of Figure 4. For example, similar to Figure 4, the thermal management system 200 of Figure 5 may include a liquid cooling system configured to conduct thermal energy away from a heat source, such as electronic components 202a, 202b. However, unlike the embodiment of Figure 4, which illustrates a balanced thermal system, the embodiment of Figure 5 illustrates a non-balanced thermal system.

[0044] As shown in FIG. 5, the first and second heat paths 217a, 217b may not be independent or isolated from each other. Rather, as shown in FIG. 5, the heat paths 217a, 217b may be in series with each other such that some heat energy collected from the first heat exchanger element 203a may be conducted to the second heat exchanger element 203b via the second heat path 217b. Similarly, some heat energy from the second heat exchanger element 203b may be conducted back to the first heat exchanger element 203a by the second heat path 217b. Beneficially, in various embodiments, the unbalanced system 200 shown in FIG. 5 may be preferred in situations where the heat load is not symmetrical. In the unbalanced system 200 of FIG. 5, for example, the cooling liquid may be routed first to the heat exchanger 203a coupled to the larger heat load and then to the second heat exchanger 203b before being conducted to the radiator 206. In contrast, for a balanced load, in which the heat load of each heat source (eg, each component 102a / 202a, 102b / 202b) is approximately the same, it may be desirable to utilize the balanced system 100 of FIG.

[0045] The system 200 shown in FIG. 5 can include a pump 209 driven by a motor 218. The pump 209 can comprise any suitable type of pump, such as a regenerative pump. In other embodiments, a piezoelectric pump or a centrifugal pump can be used. The motor 218 can comprise any suitable type of motor. In some embodiments, for example, the motor 218 can comprise a pancake type motor, which can be relatively thin to fit within the small form factor of the support structure 101. In some embodiments, the output shaft of the motor 218 is coupled to the fan 216 and the pump 209 and can rotate the fan 216 to generate airflow across the radiator 206 and simultaneously rotate the pump 209 to move liquid through the heat exchanger 203a or 203b and the radiator 206. In some embodiments, a clutch mechanism or switching mechanism can be provided such that the system can drive the fan 216 and the pump 209 separately when the fan 216 and the pump 209 share a common motor shaft and motor 218. In some embodiments, the fan 216 and pump 209 may each have an associated motor to drive the fan 216 and pump 209 separately. The pump 209 can drive liquid to the accumulator 208, which is configured to regulate the pressure of the cooling liquid, maintain a proper liquid volume, and avoid air pockets created by liquid evaporation during thermal cycling. As discussed in FIG. 6 below, the accumulator 208 can control (e.g., reduce or eliminate) the amount of air that results from the evaporation of the coolant liquid. For example, as discussed below, a pressure regulator or other device can be used to compress the liquid and avoid any voids or voids created due to evaporation.

[0046] The liquid (which may be relatively warm or hot) can be conducted to the heat-collecting radiator 206. Thermal energy from the liquid can be dissipated to the environment using fins 215. In various embodiments, internal structures (e.g., baffles) within the radiator 206 can further increase the surface area to improve heat dissipation. As discussed above, in some embodiments, a fan 216 can be used to accelerate the airflow to improve heat dissipation. In other embodiments, a fan may not be provided. Similar to FIG. 4, a fill port 207a and a vent 207b can be provided. Once the heat is dissipated by the heat-collecting radiator 206, the relatively cool liquid can be conducted along the first conduit 204a to the first fluid inlet 205a of the first heat exchanger element 203a. At least a portion of the thermal energy from the electronic component 202a can be conducted from the first heat exchanger element 203a to the cooling liquid to increase the temperature of the liquid. The liquid can then be transferred along the third conduit 204c to the second heat exchanger element 203b. The liquid in the third conduit 204c transferred away from the first heat exchanger 203a may be warmer than the liquid transferred along the first conduit 204a to the heat exchanger 203a, but the increase in temperature may be relatively slight, such that the liquid entering the second heat exchanger element 203b from the third conduit 204c is relatively cooler.

[0047] Thermal energy from the electronic component 202b may be transferred to the liquid, for example increasing the temperature of the liquid. The liquid passing from the third conduit 204c into the second heat exchanger element 203b may exit the second heat exchanger from the fluid outlet port and may enter the fifth conduit 204e, which loops back into the fluid inlet port element of the second heat exchanger 203b. The liquid may be transferred away from the second heat exchanger element 203b via the fourth conduit 204d. The liquid in the fourth conduit may be warmer than the liquid transferred to the second heat exchanger element 203b by the third conduit 204c in light of the thermal energy transferred to the liquid by the second heat exchanger element 203b. The liquid may re-enter the first heat exchanger element 203a via the second thermal path 217b. Thermal energy from the electronic component 202a and the first heat exchanger element 203a may further increase the temperature of the liquid. The resulting warm, i.e., hot liquid may be transferred back to the heat collecting radiator 206 by the second conduit 204b. The hot liquid may be at least partially cooled by the radiator 206 before passing through the pump 209 and the accumulator 208. The liquid may additionally be cooled by the radiator 206 after passing through the pump 209 and the accumulator 208.

[0048] In some embodiments, the electronic component 202a may generate more heat (or be hotter) than the electronic component 202b. Thermally coupling the hotter component 202a to the first upstream heat exchanger element 203a may improve heat dissipation because more thermal energy may be removed by the first heat exchanger element 203a than by the second heat exchanger element 203b, which may allow the system 200 to cool both the first and second components 202a, 202b in an effective manner. Similarly, if the VR or AR device is configured to select the electronic component 202a or 202b to be used, or to select the relative processing loads for the electronic components 202a, 202b, the system 200 may be configured to apply a higher processing load on the component 202a than the component 202b because thermal energy may be dissipated more efficiently by the first heat exchanger element 203a than by the second heat exchanger element 203b. In some embodiments, the first upstream heat exchanger element 203a can be made smaller (or can be made to remove less heat) than the second heat exchanger element 203b, such that each heat exchanger element 203a, 203b can be configured to remove approximately the same amount of heat energy (or a predetermined relative amount of heat energy). In other embodiments, the heat exchanger elements 203a, 203b can have approximately the same heat dissipation capacity or size.

[0049] 6 is a schematic diagram of the accumulator 208 of FIG. 5. Although shown in FIG. 6, the accumulator 208 can also be used with the system 100 shown in FIG. 4. When the thermal management system 100 or 200 is placed in the support structure 101 of the head-mounted component 58, 58A, the user may move so that air bubbles may be displaced from the liquid. Additionally, heating of the liquid inside the system 100 or 200 may lead to evaporation and further displacement of air or gas. It may be desirable to limit or control (e.g., prevent) the amount of air passing through the system 100 or 200.

[0050] The accumulator 208 of FIG. 6 can include a pressure chamber 210 through which liquid is transferred from a pump 209. A cap 212 can be slidably engaged with the pressure chamber 210 using a spring 211 or other deformable element. The accumulator 208 can include a valve 213, such as a one-way vent or valve, that allows air to enter the accumulator 208 but does not allow air to escape. As the liquid evaporates or as air or gas is otherwise displaced from the liquid, air from the outside environment enters the valve 213 and compresses the liquid and air with the cap 212 to compensate for any voids or gaps resulting from the evaporation or displacement. In various embodiments, the amount of evaporation of the liquid can be measured to predict when the device 208 should be serviced.

[0051] FIG. 7 is a schematic diagram showing a portion of a thermal management system 300 used to fill the system 300 with cooling liquid, according to various embodiments. Unless otherwise noted, the components of FIG. 7 may generally be similar to or identical to similarly numbered components of FIG. 5, with reference numbers incremented by 100 relative to the reference numbers of FIG. 5. For example, similar to FIG. 5, the system 300 may include an accumulator 308, which may include a reservoir and pressure chamber, a pump 309, and a radiator 306. A first valve V1 may selectively control the flow of liquid to the accumulator 308. A second valve V2 may selectively control the flow of liquid to the pump 309. A third valve V3 may selectively control the flow of liquid between the accumulator 308 and the pump 309.

[0052] In various embodiments, the thermal management system 300 (and / or the system 100, 200) can be filled with cooling liquid by placing the first and second valves V1, V2 in an open configuration and placing the third valve V3 in a closed configuration. The coolant liquid can be supplied through the second valve V2 into the pump 309 via a fill port (similar to the fill port 107a, 207a). The vent (similar to the vent 107b, 207b) can be immersed in an open reservoir that is filled with coolant. The pressure of the coolant liquid being supplied to the system 300 can push air out through the vent. The third valve V3 can be opened to allow liquid to pass between the accumulator 308 and the pump 309, and additional coolant liquid can be added as desired. To test the system 300, the first and second valves V1, V2 can be closed and the pump 309 can be activated to start the system 300. If air bubbles are observed or if the pump 309 suffers from cavitation, additional liquid can be supplied as described herein. (Additional Considerations)

[0053] Any process, method, and algorithm described herein and / or depicted in the accompanying figures may be embodied in code modules executed by one or more physical computing systems, hardware computer processors, application-specific circuits, and / or electronic hardware configured to execute specific and particular computer instructions, and thereby fully or partially automated. For example, a computing system may include a general-purpose computer (e.g., a server) or a special-purpose computer programmed with specific computer instructions, special-purpose circuits, etc. The code modules may be compiled and linked into an executable program, installed in a dynamic link library, or written in an interpreted programming language. In some implementations, certain operations and methods may be performed by circuitry specific to a given function.

[0054] Furthermore, certain implementations of the functionality of the present disclosure may be sufficiently mathematically, computationally, or technically complex that special purpose hardware (utilizing appropriate specialized executable instructions) or one or more physical computing devices may be required to implement the functionality, e.g., due to the amount or complexity of the calculations involved, or to provide results in substantially real-time. For example, a video may contain many frames, each frame may have millions of pixels, and specifically programmed computer hardware may be required to process the video data to provide the desired image processing task or application in a commercially reasonable amount of time.

[0055] The code modules or any type of data may be stored on any type of non-transitory computer readable medium, such as physical computer storage devices, including hard drives, solid state memory, random access memory (RAM), read only memory (ROM), optical disks, volatile or non-volatile storage devices, combinations of the same, and / or the like. The methods and modules (or data) may also be transmitted as data signals (e.g., as part of a carrier wave or other analog or digital propagated signal) generated over a variety of computer readable transmission media, including wireless-based and wired / cable-based media, and may take a variety of forms (e.g., as part of a single or multiplexed analog signal, or as multiple discrete digital packets or frames). The results of the disclosed processes or process steps may be stored persistently or otherwise in any type of non-transitory tangible computer storage device, or communicated via a computer readable transmission medium.

[0056] Any process, block, state, step, or functionality in the flow diagrams described herein and / or depicted in the accompanying figures should be understood as potentially representing a code module, segment, or portion of code that includes one or more executable instructions for implementing a specific function (e.g., logical or arithmetic) or step in the process. Various processes, blocks, states, steps, or functionality can be combined, rearranged, added to, removed from, modified, or otherwise altered from the illustrative examples provided herein. In some embodiments, additional or different computing systems or code modules may perform some or all of the functionality described herein. The methods and processes described herein are also not limited to any particular sequence, and the blocks, steps, or states associated therewith can be performed in other sequences as appropriate, e.g., serially, in parallel, or in some other manner. Tasks or events can be added to or removed from the disclosed exemplary embodiments. Furthermore, the separation of various system components in the implementations described herein is for illustrative purposes and should not be understood as requiring such separation in all implementations. It should be understood that the described program components, methods, and systems may generally be integrated together in a single computer product or packaged into multiple computer products. Many implementation variations are possible.

[0057] The process, method, and system may be implemented in a network (or distributed) computing environment. Network environments include enterprise-wide computer networks, intranets, local area networks (LANs), wide area networks (WANs), personal area networks (PANs), cloud computing networks, crowdsourced computing networks, the Internet, and the World Wide Web. The network may be a wired or wireless network or any other type of communication network.

[0058] The present invention includes methods that may be implemented using subject devices. The methods may include the act of providing such a suitable device. Such provision may be implemented by an end user. In other words, the act of "providing" merely requires the end user to obtain, access, approach, locate, configure, activate, power on, or otherwise act to provide the device required in the subject method. The methods recited herein may occur in any sequence of the recited events and the recited sequence of events that is logically possible.

[0059] The systems and methods of the present disclosure each have several innovative aspects, none of which is solely responsible for or required for the desirable attributes disclosed herein. The various features and processes described above may be used independently of one another or may be combined in various ways. All possible combinations and subcombinations are intended to fall within the scope of the present disclosure. Various modifications of the implementations described in the present disclosure may be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other implementations without departing from the spirit or scope of the present disclosure. Thus, the claims are not intended to be limited to the implementations shown herein, but should be accorded the widest scope consistent with the present disclosure, the principles, and novel features disclosed herein.

[0060] Certain features described herein in the context of separate implementations can also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation can also be implemented separately in multiple implementations or in any suitable subcombination. Furthermore, although features may be described above as acting in a combination and may even be initially claimed as such, one or more features from the claimed combination may in some cases be deleted from the combination and the claimed combination may be directed to a subcombination or variation of the subcombination. No single feature or group of features is required or essential to every embodiment.

[0061] In particular, conditional statements used herein, such as "can," "could," "might," "may," "eg," and the like, are generally intended to convey that certain embodiments include certain features, elements, and / or steps, while other embodiments do not, unless specifically stated otherwise or understood otherwise within the context as used. Thus, such conditional statements are generally not intended to agree that features, elements, and / or steps are in any way required for one or more embodiments, or that one or more embodiments necessarily include logic for determining whether those features, elements, and / or steps should be included or performed in any particular embodiment, with or without authorial input or prompting. The terms "comprising," "including," "having," and the like, are synonymous and used inclusively in a non-limiting manner and do not exclude additional elements, features, acts, operations, etc. Also, the term "or" is used in its inclusive sense (and not its exclusive sense), thus, for example, when used to connect a list of elements, the term "or" means one, some, or all of the elements in the list. In addition, the articles "a," "an," and "the," as used in this application and the appended claims, unless otherwise specified, should be interpreted to mean "one or more" or "at least one." Except as specifically defined herein, all technical and scientific terms used herein should be given the broadest possible commonly understood meaning while maintaining the validity of the claims.

[0062] As used herein, a phrase referring to "at least one of" a list of items refers to any combination of those items, including single elements. As an example, "at least one of A, B, or C" is intended to cover A, B, C, A and B, A and C, B and C, and A, B, and C. Transitive phrases such as "at least one of X, Y, and Z" are generally understood differently in the context in which they are used to convey that an item, term, etc. may be at least one of X, Y, or Z, unless specifically stated otherwise. Thus, such transitive phrases are generally not intended to suggest that an embodiment requires that at least one of X, at least one of Y, and at least one of Z, respectively, be present.

[0063] Similarly, although operations may be depicted in the figures in a particular order, it should be appreciated that such operations need not be performed in the particular order depicted, or in sequential order, or that all of the depicted operations need not be performed to achieve desirable results. Additionally, the figures may diagrammatically depict one or more exemplary processes in the form of a flow chart. However, other operations not depicted may be incorporated within the diagrammatically depicted exemplary methods and processes. For example, one or more additional operations may be performed before, after, simultaneously with, or during any of the depicted operations. Additionally, operations may be rearranged or reordered in other implementations. In some circumstances, multitasking and parallel processing may be advantageous. Additionally, the separation of various system components in the implementations described above should not be understood as requiring such separation in all implementations, and it should be understood that the described program components and systems may generally be integrated together in a single software product or packaged in multiple software products. Additionally, other implementations are within the scope of the following claims. In some cases, the actions recited in the claims may be performed in a different order and still achieve desirable results.

Claims

1. 1. A cooling system for a portable device, comprising: A heat generating element; 1. A heat transfer system comprising: a heat exchanger disposed adjacent to the heat generating element; A radiator, a fan disposed adjacent to the radiator; a heat transfer circuit in fluid communication with the heat exchanger and the radiator; a pump in fluid communication with the heat transfer circuit; a heat transfer system comprising: a motor having an output shaft coupled to at least one of the fan and the pump; an accumulator configured to reduce an amount of air in a liquid in the heat transfer circuit, the accumulator comprising: a container configured to hold at least a portion of the liquid; a closure device configured to remain at a top level of liquid regardless of the volume of said liquid medium; a spring coupled to the closure device for maintaining the closure device at a top level of the liquid; Accumulators and A cooling system comprising:

2. 2. The cooling system of claim 1, wherein the output shaft of the motor is coupled to the fan and the pump to rotate the fan to generate airflow across the radiator and simultaneously rotate the pump to move liquid through the heat exchanger and the radiator.

3. The cooling system of claim 2 , wherein the liquid comprises water and propylene glycol.

4. The cooling system of claim 1 , wherein the pump comprises a regenerative pump.

5. The cooling system of claim 1 , wherein the pump comprises a piezoelectric pump.

6. The cooling system of claim 1 , wherein the pump comprises a centrifugal pump.

7. The cooling system of claim 1 , wherein the motor comprises a pancake motor.

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