Evaporative Cooling Mechanism for Handheld Devices
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Solution Overview
Problem
Handheld electronic devices face challenges in maintaining surface temperature at or below skin temperature during extended high power operation due to insufficient natural convection cooling, which can impact device performance.
Innovation Solution
An evaporative cooling mechanism is integrated into the device, utilizing temperature-sensitive polymers in liquid retaining structures that absorb and evaporate water based on temperature, enhancing cooling capacity when natural convection is insufficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If natural convection is used to dissipate heat, then the device structure remains simple, but the cooling capacity is insufficient to maintain surface temperature below skin temperature during extended high power operation
Solution Approach 1:
The patent utilizes the phase transition of water from liquid to vapor through evaporation to provide cooling. The evaporative cooling mechanism employs water reservoirs that release water vapor to absorb heat from the device surface, leveraging the latent heat of vaporization to effectively cool the device during high power operation without requiring complex mechanical cooling systems.
Solution Approach 2:
The patent employs a water-based hydraulic cooling system where water is stored in reservoirs and delivered to cooling regions on the device surface. The water circulation and delivery mechanism uses capillary action and gravity to move water through channels and structures, providing a passive cooling solution that doesn't require complex pumps or mechanical components.
2Power
If natural convection cooling is relied upon, then the device maintains simplicity, but the power envelope is limited due to insufficient cooling capacity
Solution Approach 1:
The evaporative cooling mechanism provides enhanced cooling capacity by utilizing water evaporation, enabling the device to sustain higher power levels for extended periods. The phase transition from liquid to vapor absorbs significant heat energy, allowing the device to maintain acceptable surface temperatures even during high power operation that would otherwise be unsustainable with natural convection alone.
3Productivity
If high power operation is maintained, then device performance is optimized, but surface temperature exceeds skin temperature without additional cooling
Solution Approach 1:
The evaporative cooling mechanism activates during high power operation to remove excess heat through water evaporation. The water vapor generated absorbs heat from the device surface, maintaining temperatures below skin temperature thresholds and enabling sustained high performance without thermal throttling or performance reduction.
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 evaporative cooling mechanism effectively maintains surface temperature at or below skin temperature during extended high power operations, allowing for increased power envelope and extended usage without reducing device performance.
Implementation Method 1
the temperature sensitive polymer is hydrophilic and absorbs liquid from atmosphere surrounding the electronic device to store the absorbed liquid in the plurality of liquid retaining structures when the temperature of the second surface is below the threshold temperature
Implementation Method 2
the temperature sensitive polymer is hydrophobic and repels the liquid stored in the plurality of liquid retaining structures when the temperature of the second surface exceeds the threshold temperature
Implementation Method 3
the evaporative cooling mechanism evaporates the liquid stored in the plurality of liquid retaining structures to the atmosphere surrounding the electronic device, when the temperature of the second surface exceeds the threshold temperature
Implementation Method 4
The heat sink distributes heat generated from the at least one IC across the second surface of the electronic device to maintain temperature of the first surface and the second surface of the electronic device below a threshold temperature
Data Source
AI summary
An apparatus and method of the disclosure provides a cooling mechanism for a handheld electronic device. The cooling mechanism includes a heat sink and an evaporative cooling mechanism. The evaporative cooling mechanism includes liquid retaining structures. The liquid retaining structures are located in proximity to the at least one IC of the handheld electronic device. Each liquid retaining structure is coated with a temperature sensitive polymer that act as hydrophilic when the temperature of the surface of the handheld electronic device is below a threshold temperature. To maintain the temperature of the surface of the handheld electronic device below the threshold temperature, the temperature sensitive polymer act as hydrophobic and evaporates the liquid stored in the liquid retaining structures to the atmosphere surrounding the handheld electronic device when the temperature of the surface of the electronic device is above the threshold temperature.