Electrowetting Surface Cleaning Device Resonant Droplet Removal
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Solution Overview
Problem
Existing surface cleaning technologies are inefficient in removing liquid droplets from surfaces, particularly on inclined or complex geometries, and struggle to effectively manage fine droplets due to limitations in voltage control and frequency resonance.
Innovation Solution
A surface cleaning device utilizing an electrowetting element with a substrate, electrodes, and a dielectric layer, controlled by a power source that supplies alternating-current (AC) power at specific frequencies and voltages to resonate and vibrate droplets, optimizing their removal by detecting resonant frequencies and adjusting voltage levels to expand the electric field's range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional cleaning methods are used, then the cleaning process is simple, but the efficiency of removing liquid droplets is low
Solution Approach 1:
The patent applies mechanical vibration by using AC electrowetting to induce resonant vibration in liquid droplets. The alternating electric field causes the droplet to oscillate at its resonant frequency, generating mechanical energy that overcomes pinning forces and friction, enabling efficient droplet removal from surfaces including fine droplets that conventional methods cannot effectively clean.
2Productivity
If voltage is increased to remove fine droplets, then cleaning effectiveness improves, but energy consumption increases
Solution Approach 1:
The patent employs parameter changes by dynamically adjusting the AC voltage frequency to match the resonant frequency of the droplet. Instead of continuously applying high voltage, the system sweeps through frequencies to identify and excite the droplet's natural resonance mode, thereby achieving effective droplet removal at lower energy levels by exploiting the droplet's inherent vibrational characteristics.
Solution Approach 2:
The patent utilizes periodic action by applying AC voltage at the droplet's resonant frequency. The alternating electric field periodically excites the droplet, building up vibrational amplitude through resonance. This periodic excitation is more energy-efficient than continuous high-voltage application because it leverages the droplet's natural oscillation cycle, progressively amplifying motion with minimal energy input.
3Productivity
If AC electrowetting is applied, then droplet vibration and removal efficiency improves, but control complexity increases
Solution Approach 1:
The patent implements feedback control by monitoring the droplet's response to applied AC voltage and adjusting the frequency accordingly. The system detects the droplet's resonant frequency through its vibrational response and automatically tunes the AC electrowetting frequency to match, ensuring optimal droplet excitation. This feedback mechanism simplifies control by allowing the system to self-adjust rather than requiring precise pre-programmed frequency sequences.
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 device efficiently removes liquid droplets by resonating them at optimal frequencies and voltages, ensuring quick and thorough cleaning, including fine droplets, by maximizing mechanical energy and reducing friction, thus enhancing surface cleanliness.
Implementation Method 1
when an electric field is applied to a liquid, particularly a liquid in the form of a droplet, placed on a solid, the contact angle and surface tension of the fluid with respect to the solid change. This behavior is defined as the electrowetting effect or phenomenon.
Implementation Method 2
a periodic change of an electrostatic force generated at the electrodes
Implementation Method 3
supplying a first AC power having a predetermined first frequency and a predetermined first voltage to the electrodes during a first time period to vibrate a droplet on the surface of the object by a periodic change of an electrostatic force generated at the electrodes, wherein the first frequency is set as a resonant frequency of the liquid droplet
Data Source
Figure 1
Figure 2(a)~2(c)
Figure 3
AI summary
A device (100) for cleaning an object (O) surface, including a substrate (110) provided on the object surface, a plurality of electrodes (120) provided on the substrate (110), a dielectric layer (130) provided on the substrate (110) to cover the electrodes (120), and a control device (400) supplying an alternating-current (AC) power to the electrodes (120) including supplying a first AC power having a predetermined first frequency and a predetermined first voltage to the electrodes (120) during a first time period to vibrate a droplet (D) on the surface of the object (O) by a periodic change of an electrostatic force generated at the electrodes (120), the first frequency being set to the resonant frequency of the liquid droplet (D).