OLED Substrate Grooves for Uniform Inkjet Printing
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Solution Overview
Problem
Inkjet printing of organic light-emitting display substrates faces challenges with non-uniform film formation due to varying solvent volatilization rates across the display area, leading to inconsistencies in film thickness and density, resulting in swatch mura and reduced image quality.
Innovation Solution
A pixel defining layer with crisscrossing dams and grooves is used to create frame-shaped areas that accommodate a solvent with the same material as the ink, ensuring consistent ambient conditions for inkjet printing, which improves the uniformity of film formation by matching volatilization speeds across the display area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If the inkjet head repeatedly sweeps on a large-sized panel for multiple times, then the entire panel can be printed, but the organic solvent in pixel units at different positions volatilizes at different speeds causing non-uniform film formation and swatch mura
Solution Approach 1:
The pixel defining layer with grooves is formed in advance before inkjet printing. The grooves are pre-configured to accommodate solvent and regulate volatilization, creating a controlled environment that compensates for position-dependent volatilization differences during the printing process.
Solution Approach 2:
The pixel defining layer introduces local structural variations through grooves at different positions. Each groove is locally optimized to accommodate solvent and regulate volatilization rate, creating position-specific micro-environments that compensate for the overall non-uniform volatilization across the large display area.
2Reliability
If a pixel defining layer is added to prevent ink overflow, then ink can be contained in pixel areas, but the complex dam structure creates inconsistent ambient conditions for solvent volatilization
Solution Approach 1:
The pixel defining layer incorporates grooves with specific local geometries that create position-dependent solvent accommodation capabilities. Each groove is locally optimized to regulate volatilization rate, transforming the pixel defining layer from a simple containment structure into an active uniformity-control device.
Solution Approach 2:
The groove depth, width, and shape are optimized to change the volatilization parameters of the organic solvent. By adjusting the groove dimensions, the solvent volatilization rate can be regulated to compensate for position-dependent environmental differences, achieving uniform film formation.
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 enhances the uniformity of the film layer and display brightness by maintaining consistent solvent ambience and volatilization rates, reducing swatch mura and improving the overall image quality.
Implementation Method 1
the groove is used for accommodating a solvent when forming an organic light-emitting element by inkjet printing
Data Source
AI summary
Disclosed is an organic light-emitting display substrate, including a substrate and a pixel defining layer on the substrate which includes a plurality of dams crisscrossing in a display area of the substrate to define a plurality of pixel units and define the boundary of the display area, wherein the pixel defining layer further includes a groove arranged on a top surface of each dam, the grooves at least define one frame-shaped area, at least one pixel unit is arranged in each frame-shaped area, and the grooves are used for accommodating a solvent when forming an organic light-emitting element by inkjet printing. Also disclosed is a manufacturing method of an organic light-emitting display substrate and a display device. The present invention can improve the film forming effect of a film layer formed on the substrate, so that the brightness of a display image of the display device is more uniform.