Electrowetting Display Filling Apparatus for Uniform Ink Distribution
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Solution Overview
Problem
Current electrowetting display device filling methods are plagued by slow filling speed, poor uniformity, ink wastage, and difficulties in mass production due to the need for precise control of air-ink interfaces in electrolyte solutions, which are challenging to stabilize, especially for larger displays.
Innovation Solution
A drying-wetting separated filling method where a non-polar solution is filled into pixel grids on a lower substrate in air, followed by immediate coverage with a polar solution using a scraper with a liquid filling channel, allowing for faster and more uniform filling without the need for electrolyte solutions, and an accompanying apparatus featuring a cofferdam and scraper for peripherally sealed filling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional liquid-separation filling method is used to fill non-polar solution in polar electrolyte solution environment, then uniform filling can be achieved, but filling speed becomes extremely slow (0.1-0.5 mm/s) and mass production is difficult
Solution Approach 1:
The patent divides the filling process into two separate stages: first filling the non-polar solution in air environment, then filling the polar solution to cover it. This segmentation allows each filling operation to occur in its optimal environment, achieving both high speed and uniformity without the constraints of traditional single-step electrolyte-based methods
Solution Approach 2:
The patent introduces air as an intermediary medium for the first filling stage. By using air instead of polar electrolyte solution as the filling medium for the non-polar solution, the method eliminates the slow interface control requirements while maintaining filling uniformity through the subsequent polar solution coverage
2Ease of manufacture
If vertical immersion filling method is used, then filling can be completed, but large amount of polar electrolyte solution is required and filling speed is slow (0.5 mm/s)
Solution Approach 1:
The patent extracts the non-polar solution filling process from the polar electrolyte solution environment. By taking out the first filling stage from the electrolyte environment and performing it in air, the method dramatically reduces electrolyte solution consumption while maintaining manufacturing feasibility through the subsequent coverage step
3Manufacturing precision
If Liquavista liquid-separation filling method is used with air bubble and non-polar solution ratio control, then uniform filling is achieved, but process complexity increases and mass production becomes difficult
Solution Approach 1:
The patent employs a scraper that automatically controls the filling process. The scraper's movement and the liquid filling channel work together to self-regulate the non-polar solution distribution and subsequent polar solution coverage, eliminating the need for complex air bubble ratio control systems while maintaining filling uniformity
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
This method achieves a significantly faster filling speed of up to 6 cm/s with improved uniformity and reduced ink consumption, making it suitable for industrial-scale production and reducing costs associated with using expensive ionic liquids.
Implementation Method 1
a non-polar solution 5 is filled into pixel grids on a lower substrate of an electrowetting display device, in air
Implementation Method 2
two immiscible polar solution 4 and non-polar solution 5 filled in a sealed cavity
Implementation Method 3
two immiscible polar solution 4 and non-polar solution 5 filled in a sealed cavity
Implementation Method 4
a polar solution 4 is filled at a side of the scraper where the non-polar solution 5 is already filled, such that the polar solution 4 can immediately cover the non-polar solution 5
Implementation Method 5
An electrowetting display device uses an electrowetting principle to change a wettability of an electrolyte solution on a surface of a hydrophobic insulating layer by applying a voltage
Implementation Method 6
a hydrophobicity of a material of the pixel wall 6 is lower than the hydrophobicity of the hydrophobic insulating layer 7, a wettability of the polar solution 4 is different from a wettability of the non-polar solution 5 on the surface of the pixel wall 6
Data Source
AI summary
Disclosed is a drying-wetting separated filling method and a filling apparatus for an electrowetting display device. The filling method comprises filling a non-polar solution into pixel grids on a lower substrate of an electrowetting display device in air, and filling a polar solution to immediately cover the non-polar solution filled after filling the non-polar solution into the pixel grids. Compared with filling the non-polar solution into the polar solution, directly filling the non-polar solution in air has better filling uniformity, easier operation and control. With the method, the fillings of the polar solution and the non-polar solution are easy, having a higher filling efficiency, and no air bubble residue.