MEMS Cooling Element Cavities for Compact Active Heat Dissipation
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Solution Overview
Problem
Current cooling solutions for computing devices, such as fans and passive heat spreaders, are inadequate for effectively managing heat in both mobile and larger devices like smartphones and laptops, leading to performance throttling due to insufficient heat dissipation and space/power constraints.
Innovation Solution
A micro-electro-mechanical system (MEMS) cooling system with a centrally anchored cooling element featuring a cantilevered arm and cavities, driven by piezoelectric actuation, which generates high-speed fluid flow to efficiently dissipate heat from heat-generating structures within limited spaces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If active cooling devices such as fans are used, then heat dissipation capability is improved, but device size and power consumption increase
Solution Approach 1:
The patent employs ultrasonic vibration of a diaphragm membrane to generate acoustic waves that drive fluid flow through the cooling system. The diaphragm vibrates at ultrasonic frequencies (20-100 kHz) to create pressure variations that propel coolant through channels and over heat-generating components, eliminating the need for traditional rotating fans while achieving effective heat dissipation in a compact form factor
Solution Approach 2:
The invention uses acoustic pressure waves generated by ultrasonic vibration to move fluid through the cooling system. The acoustic field creates regions of high and low pressure that drive coolant flow through channels and across heat sinks, replacing mechanical fan-driven airflow with acoustic field-driven fluid motion, thereby reducing device size and power consumption while maintaining cooling effectiveness
2Volume of moving object
If passive cooling devices such as heat spreaders are used, then device size is reduced, but heat dissipation capability becomes insufficient
Solution Approach 1:
The patent introduces ultrasonic vibration to actively drive fluid flow through the cooling system, transforming a passive heat spreader into an active cooling device. The vibrating diaphragm creates acoustic waves that pump coolant through channels and enhance convective heat transfer, providing sufficient heat dissipation capability while maintaining a compact device size suitable for mobile computing devices
Solution Approach 2:
The ultrasonic vibration system is integrated directly into the heat spreader structure, allowing the same component to both spread heat passively through conduction and actively drive fluid flow through acoustic waves. This self-service approach eliminates the need for separate active cooling components, maintaining compact size while achieving adequate heat dissipation
3Temperature
If cooling solutions are incorporated into mobile devices, then heat dissipation is improved, but space and power constraints are violated
Solution Approach 1:
The patent combines the heat spreader and ultrasonic vibration source into a single integrated cooling system. The diaphragm that spreads heat thermally also serves as the vibration source that generates acoustic waves for fluid propulsion. This merging of functions eliminates the need for separate active cooling components, achieving effective heat dissipation within the strict space constraints of mobile devices
Solution Approach 2:
The diaphragm structure serves multiple functions simultaneously: it acts as a thermal conduction path for heat spreading, a vibration source for generating acoustic waves, and a fluid drive mechanism for propelling coolant flow. This multi-functionality allows the cooling system to achieve effective heat dissipation while occupying minimal space and consuming low power, making it suitable for mobile computing devices
4Temperature
If traditional fan-based cooling is used, then heat dissipation is adequate, but power consumption increases
Solution Approach 1:
The patent replaces the mechanical fan system with an acoustic field-based fluid drive system. Instead of using electrical motors to rotate fan blades, the invention uses ultrasonic piezoelectric actuators to generate acoustic waves that drive fluid flow. This substitution eliminates mechanical friction and motor losses, significantly reducing power consumption while maintaining adequate heat dissipation capability
Solution Approach 2:
The ultrasonic diaphragm vibrates at high frequencies (20-100 kHz) to create periodic pressure variations that drive fluid flow through the cooling system. This high-frequency periodic action creates efficient acoustic pumping with minimal energy input, as the rapid oscillations generate sufficient pressure differentials to move coolant through channels and enhance convective heat transfer without requiring large amounts of power
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 MEMS cooling system enhances heat transfer efficiency, allowing for higher processor speeds and longer operation times without throttling, while being compact and power-efficient, suitable for use in mobile devices and other space-constrained applications.
Implementation Method 1
driven by piezoelectric actuation
Implementation Method 2
generates high-speed fluid flow
Implementation Method 3
efficiently dissipate heat from heat-generating structures
Implementation Method 4
enhances heat transfer efficiency
Data Source
AI summary
A cooling system including a support structure and a cooling element is described. The cooling element has a thickness and includes an anchored region and a cantilevered arm. The anchored region is coupled to and supported by the support structure. The cantilevered arm extends outward from the anchored region. The cantilevered arm includes at least one cavity therein. The at least one cavity has a depth of at least one-third and not more than three-fourths of the thickness of the cooling element. The cooling element is configured to undergo vibrational motion when actuated to drive a fluid for cooling a heat-generating structure.