Phone Case Thermal Ground Plane for Hotspot Management
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Solution Overview
Problem
Smartphones often develop hotspots during computationally intensive tasks, leading to ergonomic discomfort and limited power due to inadequate cooling, as they primarily rely on convection for heat dissipation.
Innovation Solution
A phone case with an embedded or coupled thermal ground plane that includes a liquid transport layer, vapor transport layer, and a heat transfer fluid, along with features like foldable fins and wireless charging compatibility, to enhance heat dissipation and thermal conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If smartphones rely on convection for heat dissipation, then the cooling mechanism is simple, but the heat dissipation efficiency is insufficient leading to hotspots
Solution Approach 1:
The patent employs phase change material (paraffin wax) that transitions from solid to liquid state to absorb heat during phase change, and from liquid to vapor state to transport heat away from the hotspot. This phase transition mechanism enables efficient heat dissipation without requiring complex active cooling systems, directly resolving the contradiction between simple cooling mechanism and heat dissipation efficiency.
Solution Approach 2:
The patent utilizes capillary action through porous materials and wick structures to transport the heat transfer fluid (liquid paraffin) through the thermal ground plane without requiring pumps or external power. The capillary forces naturally drive the fluid through the porous medium, providing passive yet effective heat transport that maintains simplicity while improving heat dissipation capability.
2Temperature
If a thermal ground plane is embedded in the phone case, then heat transfer efficiency improves, but the device complexity increases
Solution Approach 1:
The patent integrates the thermal ground plane directly into the phone case structure, merging the protective case function with the thermal management function. The phone case body itself becomes part of the thermal conduction path, eliminating the need for separate cooling components and reducing overall device complexity while maintaining effective heat transfer.
Solution Approach 2:
The thermal ground plane utilizes composite structures combining metal layers (for thermal conduction), porous materials (for fluid transport), and phase change materials (for heat absorption). This composite approach achieves superior thermal management within a compact integrated structure that fits within the phone case without significantly increasing complexity.
3Temperature
If the thermal ground plane includes metal areas, then thermal conductivity increases, but wireless charging is blocked
Solution Approach 1:
The patent implements spatially varying material properties in the thermal ground plane, using metal materials only in regions where thermal conduction is needed and dielectric or RF-transparent materials in regions where wireless charging occurs. This local differentiation allows the system to simultaneously achieve high thermal conductivity in critical areas while maintaining wireless charging compatibility in other areas.
Solution Approach 2:
The thermal ground plane is divided into multiple functional zones: metal regions for heat conduction, porous regions for fluid transport, and dielectric regions for wireless charging compatibility. This segmentation allows each zone to perform its specific function optimally without interfering with other functions, resolving the conflict between thermal conductivity and wireless charging.
4Productivity
If computationally intensive tasks are performed, then processing power increases, but heat generation increases causing ergonomic discomfort
Solution Approach 1:
The thermal management system operates passively without requiring external power or user intervention. The phase change material automatically absorbs heat when temperatures rise, and the capillary action automatically transports the heat away, creating a self-regulating system that handles heat from computationally intensive tasks without adding complexity or requiring active control.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The thermal ground plane increases the effective thermal conductivity of the phone case, allowing for more efficient heat transfer and reducing hotspot temperatures, thereby improving user comfort and extending the phone's power dissipation capabilities.
Implementation Method 1
The thermal ground plane, for example, may include a first casing; a liquid transport layer comprising a mesh or an array of pillars; a vapor transport layer comprising a mesh or an array of pillars; and a second casing, an outer periphery of the first casing and an outer periphery of the second casing are sealed together encasing the liquid transport layer, the vapor transport layer, and a heat transfer fluid
Implementation Method 2
a liquid transport layer comprising a mesh or an array of pillars; a vapor transport layer comprising a mesh or an array of pillars
Data Source
AI summary
A phone case with a phone case body and a thermal ground plane is disclosed. The phone case, for example, may include fin that folds, bends, and/or extends outward from the phone case body. The phone case, for example, may include a magnetic area that comprises a toroid or donut shape. The phone case, for example, may include an aperture that extends through the phone case body and/or the thermal ground plane. The thermal ground plane may include a first casing; a liquid transport layer comprising a mesh or an array of pillars; a vapor transport layer comprising a mesh or an array of pillars; and a second casing, an outer periphery of the first casing and an outer periphery of the second casing are sealed together encasing the liquid transport layer, the vapor transport layer, and a heat transfer fluid.