OLED Array Substrate Pixel Defining Layer Ink Overflow Prevention
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Solution Overview
Problem
Existing inkjet printing technologies face challenges in producing high-resolution OLED panels due to ink overflow, which causes undesirable color mixing between pixel units, especially when dealing with small-sized pixel units.
Innovation Solution
The array substrate design features a pixel defining portion with a hydrophobic layer on one side and a hydrophilic layer on the other, with varying heights and widths to prevent ink overflow, allowing for precise ink dispensing and separation of sub-pixels, enabling efficient inkjet printing of high-resolution OLED panels without color contamination.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If conventional inkjet printing is used to deposit organic material ink, then material cost is reduced, but ink overflow occurs causing color mixing between adjacent pixel units
Solution Approach 1:
The pixel defining layer is segmented into multiple layers (first pixel defining layer and second pixel defining layer) with different heights, creating distinct containment zones for ink in different pixel regions. This segmentation prevents ink overflow from spreading to adjacent pixel units while maintaining cost-effective inkjet printing.
Solution Approach 2:
Different regions of the pixel defining layer are given different heights and properties - the first pixel defining layer has a first height for containing ink in specific areas, while the second pixel defining layer has a second height for other areas. This local differentiation of structural properties enables precise ink containment in each pixel unit.
2Manufacturing precision
If pixel unit size is reduced to increase resolution, then display quality improves, but ink overflow risk increases causing color contamination
Solution Approach 1:
The solution moves from two-dimensional planar containment to three-dimensional stepped containment by creating pixel defining layers with different heights. This vertical dimension addition provides enhanced ink containment capability within the same planar footprint, enabling smaller pixel units with reliable ink containment.
Solution Approach 2:
The pixel defining layers are formed beforehand to create predetermined containment structures with different heights. These pre-formed structures act as barriers that prevent ink overflow before it can cause color contamination, providing a cushioning effect against potential printing errors.
3Ease of manufacture
If single-layer pixel defining structure is used, then manufacturing process is simple, but ink overflow cannot be effectively prevented
Solution Approach 1:
The pixel defining structure is divided into multiple layers with different heights, where the first pixel defining layer and second pixel defining layer work together to provide comprehensive ink containment. This segmentation enables effective overflow prevention while maintaining manufacturing feasibility through sequential layer formation.
Solution Approach 2:
The pixel defining structure uses composite construction with multiple layers having different properties and heights. This composite approach combines the advantages of different layer configurations to achieve both effective ink containment and manufacturing practicality.
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 allows for high-resolution OLED panel production with reduced risk of ink overflow and color contamination, improving the efficiency of the inkjet printing process and ensuring uniformity within sub-pixel units.
Implementation Method 1
each of the first pixel defining portion and the second pixel defining portion may comprise a hydrophobic layer and a hydrophilic layer
Implementation Method 2
each of the first pixel defining portion and the second pixel defining portion may comprise a hydrophobic layer and a hydrophilic layer
Implementation Method 3
A largest height of the first pixel defining portion may be lower than a largest height of the second pixel defining portion
Data Source
AI summary
The present disclosure generally relates to display technologies, and in particular, to an array substrate, a method of fabricating array substrate, a display panel including the array substrate, and a display device including the display panel. The array substrate includes a substrate; a plurality of sub-pixel units provided on the substrate, each sub-pixel unit including a pair of sub-pixels; a first pixel defining portion provided between the pair of sub-pixels in a sub-pixel unit; a second pixel defining portion provided between a pair of adjacent sub-pixel units. The height of the first pixel defining portion is lower than the height of the second pixel defining portion.