Display Substrate Pixel Definition Layer Ink Drying Uniformity
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Solution Overview
Problem
Ink-jet printing on display substrates results in non-uniform ink drying speeds between the edge and interior of the substrate, leading to uneven morphology of the organic functional layer and subsequent display brightness issues in organic light-emitting display devices.
Innovation Solution
A display substrate with a pixel definition layer comprising a display pixel definition region and an assistant pixel definition region, where the assistant pixel definition region has larger opening areas than the display pixel definition region, arranged in a matrix configuration to balance ink drying speeds through proportional ink amounts in each pixel definition unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If ink-jet printing is performed on the display substrate, then the organic functional layer is formed, but the ink drying speed becomes non-uniform between edge and interior regions, resulting in uneven morphology
Solution Approach 1:
The patent applies local quality by differentiating the opening areas of pixel definition units based on their location. Display pixel definition units in the interior region have larger opening areas to maintain slower drying speed, while assistant pixel definition units in the peripheral region have smaller opening areas to achieve faster drying speed. This localized differentiation ensures uniform ink drying across the entire substrate, resolving the contradiction between manufacturing precision and display reliability.
2Manufacturing precision
If the pixel definition layer covers the entire substrate including peripheral area, then ink drying uniformity is improved, but the bezel space increases
Solution Approach 1:
The patent applies parameter changes by modifying the opening area parameter of pixel definition units based on their spatial location. By adjusting this critical parameter - larger for display pixels, smaller for assistant pixels - the system achieves uniform ink drying speed across different regions without requiring uniform coverage throughout the entire substrate, thus reducing bezel space while maintaining manufacturing precision.
Solution Approach 2:
The patent implements local quality by creating different types of pixel definition units with different opening areas in different regions. The assistant pixel definition units in the peripheral area have smaller opening areas compared to display pixel definition units, allowing the peripheral region to dry faster and match the interior drying speed, thereby achieving uniformity without expanding the overall substrate area or bezel space.
3Manufacturing precision
If assistant pixel definition units with larger opening areas are added in the peripheral region, then ink drying speed uniformity is achieved, but the device complexity increases
Solution Approach 1:
The patent applies universality by designing assistant pixel definition units that, while having different opening areas, perform the same fundamental function as display pixel definition units - defining regions for organic functional material deposition. This multi-functional approach allows the same structural element to serve different purposes (display vs. drying rate control) without significantly increasing device complexity, as the basic unit structure remains the same.
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
The solution achieves uniform morphology of the organic functional layer, improving display uniformity and reducing bezel space, simplifying fabrication, and saving costs by balancing ink drying speeds and reducing vapor pressure differences.
Implementation Method 1
non-uniform ink drying speeds between the edge and interior of the substrate, leading to uneven morphology of the organic functional layer
Data Source
AI summary
A display substrate and preparation method thereof, an ink-jet printing method and a display device are provided. The display substrate includes a display area, a peripheral area, and a pixel definition layer; the pixel definition layer including: a display pixel definition region and an assistant pixel definition region surrounding the display pixel definition region; the display pixel definition region includes a plurality of first pixel definition units; the assistant pixel definition region includes a plurality of second pixel definition units, and opening areas of the second pixel definition units are respectively greater than those of the first pixel definition units; the display pixel definition region is in the display area, the assistant pixel definition region is in the peripheral area, the plurality of first pixel definition units is configured to form display pixels, and the plurality of second pixel definition units is configured to form assistant pixels.