Color Filter Substrate Wells and Channels for Uniform Ink Thickness
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Solution Overview
Problem
The existing inkjet printing method for forming color filter layers often results in uneven thickness due to the coffee stain effect, where solvent evaporation rates differ between areas in contact with and not in contact with the light blocking layer, leading to non-uniform color filter layers.
Innovation Solution
A color filter substrate is fabricated with a light blocking layer featuring wells and channels that allow color ink to flow uniformly, connecting openings and forming a matrix of color layers with varying colors, ensuring even thickness by spraying ink onto both substrate openings and light blocking layer channels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If color ink is sprayed onto the substrate through openings in the light blocking layer, then the color filter layer is formed, but the thickness becomes uneven due to the coffee stain effect
Solution Approach 1:
The light blocking layer is segmented into multiple wells with channels connecting them, creating a structured pattern that divides the ink deposition area into controlled segments. This segmentation allows uniform ink distribution through the channels while preventing the coffee stain effect that occurs in continuous areas.
Solution Approach 2:
Different regions of the light blocking layer are given different properties: wells provide enclosed spaces for controlled ink deposition, while channels provide pathways for uniform ink flow. This local differentiation of structure and function ensures uniform thickness by controlling where and how ink is deposited in each local region.
2Ease of manufacture
If openings are formed through the light blocking layer for inkjet printing, then color ink can be sprayed, but uneven evaporation occurs between areas in contact with and not in contact with the light blocking layer
Solution Approach 1:
The light blocking layer is segmented into multiple wells with channels connecting them, creating a structured pattern that divides the ink deposition area into controlled segments. This segmentation allows uniform ink distribution through the channels while preventing the coffee stain effect that occurs in continuous areas.
Solution Approach 2:
Different regions of the light blocking layer are given different properties: wells provide enclosed spaces for controlled ink deposition, while channels provide pathways for uniform ink flow. This local differentiation of structure and function ensures uniform thickness by controlling where and how ink is deposited in each local region.
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 approach ensures a uniform thickness of the color filter layer by allowing the solvent to evaporate consistently across the substrate, eliminating the coffee stain effect and improving layer uniformity.
Implementation Method 1
When the color ink 4 having a volatile solvent is cured, a portion of the color ink 4 making contact with the light blocking layer 2 evaporates more quickly than a portion of the color ink 4 that does not make contact with the light blocking layer 2
Implementation Method 2
The coffee stain effect reveals that during drying of a liquid, the interaction of surface tension and evaporation may cause an uneven distribution of material left behind
Data Source
AI summary
A color filter substrate comprising a substrate, a light blocking layer on the substrate having a plurality of wells with bottoms that contact the substrate, and a plurality of channels between the wells, and a color layer material which fills the wells and channels.