Electrowetting Display Color Filter Thickness Variation
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Solution Overview
Problem
Electrowetting display apparatuses face challenges in improving color reproducibility without compromising brightness, particularly due to crosstalk and cell gap issues.
Innovation Solution
The design includes a first and second substrate with a fluid layer and a color filter on the second substrate, where the color filter thickness varies to reduce cell gap, and the black fluid layer's height exceeds the shortest distance to the substrate, minimizing crosstalk and enhancing brightness by optimizing light reflection and transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a uniform thickness color filter is used, then the manufacturing process is simple, but color reproducibility is poor and crosstalk occurs
Solution Approach 1:
The color filter is designed with non-uniform thickness, being thicker at the pixel edges and thinner at the center. This local variation in thickness compensates for light leakage at edges, improving color reproducibility and reducing crosstalk between adjacent pixels while maintaining overall manufacturing feasibility.
2Manufacturing precision
If the cell gap is reduced to reduce crosstalk, then color reproducibility improves, but brightness is compromised
Solution Approach 1:
The color filter's non-uniform thickness distribution allows the device to maintain a larger overall cell gap for brightness while locally addressing crosstalk at pixel edges. The thicker edges reduce light leakage without requiring a complete reduction of the cell gap, thus preserving brightness.
Solution Approach 2:
Instead of reducing the cell gap (one-dimensional solution), the invention addresses crosstalk by modifying the color filter thickness distribution (another dimension). This approach reduces crosstalk through optical path control rather than geometric confinement, preserving brightness.
3Manufacturing precision
If the color filter thickness is increased to improve color reproducibility, then manufacturing cost increases due to material usage
Solution Approach 1:
The color filter uses increased thickness only where needed (at pixel edges) rather than uniformly across the entire filter area. This localized material distribution achieves improved color reproducibility and crosstalk reduction while minimizing overall material consumption and manufacturing cost.
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 configuration improves color reproducibility by up to 30% and reduces manufacturing costs through efficient use of materials while maintaining brightness across gray-scale levels.
Implementation Method 1
An electrowetting display apparatus displays images using an electrowetting phenomenon that causes the movement or deformation of fluid by applying a voltage to the fluid in order to change the surface tension of the fluid.
Implementation Method 2
enhancing brightness by optimizing light reflection and transmission
Data Source
AI summary
An electrowetting display apparatus includes a first substrate including a first electrode that receives a gray-scale voltage and a second electrode insulated from the first electrode and receiving a reference voltage, a second substrate, a fluid layer, and a color filter. The color filter has a first thickness in an area corresponding to the first electrode and a second thickness in an area corresponding to the second electrode, and the first thickness is larger than the second thickness. Accordingly, a cell gap of the electrowetting display apparatus is reduced, and color reproducibility of the electrowetting display apparatus is improved without sacrificing brightness.