Display Substrate Ink Injection Surface Energy Control
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Solution Overview
Problem
Existing display substrate manufacturing processes face challenges in achieving the required surface energy properties for pixel definition layers, leading to issues with ink material flatness and planarization, resulting in thin ink thickness and increased difficulty in subsequent layer formation.
Innovation Solution
A display substrate with a pixel definition layer and a functional medium layer having distinct surface energy portions, where the side surfaces have a higher surface energy than the top surface, and a body material layer with a rough bottom surface, allowing for increased ink thickness and improved planarization, achieved through photo-grafting of lyophilic monomers on lyophobic polymers and dry-etching to create a rough surface.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the pixel definition layer has uniform surface energy, then the manufacturing process is simple, but the ink material cannot be kept flat and the ink thickness becomes thin
Solution Approach 1:
The pixel definition layer is modified to have different surface energy characteristics in different regions: the side surfaces have high surface energy to attract and hold ink material, while the top surface has low surface energy to prevent ink overflow and maintain flatness. This local differentiation resolves the contradiction between manufacturing simplicity and ink quality.
Solution Approach 2:
The functional medium layer is segmented into two distinct portions: a first portion covering the side surfaces of subpixel openings with high surface energy, and a second portion covering the top surface of the pixel definition layer with low surface energy. This segmentation allows each portion to perform its specific function independently, achieving both thick ink deposition and flat ink surface.
2Quantity of substance
If more ink material is used to improve color gamut, then the optical performance improves, but the ink overflows the pixel definition layer
Solution Approach 1:
By creating localized differences in surface energy within the pixel definition layer, the invention allows different regions to serve different purposes: side surfaces with high surface energy accommodate more ink material for improved color gamut, while the top surface with low surface energy maintains ink flatness and prevents overflow.
3Quantity of substance
If the ink thickness is increased to improve color gamut, then the optical performance improves, but the planarization difficulty increases
Solution Approach 1:
The invention creates a pixel definition layer with spatially varying surface energy properties that naturally guide the ink to form a thick yet flat structure. The high surface energy side surfaces enable thick ink deposition, while the low surface energy top surface ensures flat ink formation, thereby improving color gamut without increasing planarization difficulty.
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 solution enables thicker ink-type display patterns in subpixel openings, reducing planarization difficulties and enhancing optical performance by allowing more ink material to be used without overflowing, resulting in improved color gamut and light conversion efficiency.
Implementation Method 1
Both of the first and second portions include a lyophobic polymer photo-grafted with a lyophilic monomer material, and a grafting ratio of the first portion is greater than a grafting ratio of the second portion
Implementation Method 2
A portion of the body material layer covering the bottom of the subpixel opening serves as a third portion, and a surface of the third portion away from the base substrate is a rough surface. The rough surface has a roughness in a range from 2 μm to 10 μm
Data Source
AI summary
The disclosure provides a display substrate, a manufacturing method thereof and a display device. The display substrate has a plurality of subpixel regions. The display substrate includes a base substrate and a pixel definition layer on the base substrate. The pixel definition layer defines a plurality of subpixel openings and each of the subpixel openings occupies one subpixel region. The display substrate further includes a functional medium layer on a side of the pixel definition layer away from the base substrate. The functional medium layer includes a first portion covering side surfaces of the subpixel opening and a second portion covering a top surface of the pixel definition layer. In the same subpixel region, surface energy of the first portion is greater than surface energy of the second portion.