Inkjet Printed OLED Functional Layer Solvent Gradient
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Solution Overview
Problem
Inkjet printing of OLEDs results in non-uniform film thickness due to uneven solvent vaporization, leading to unsatisfactory display performance and the need for a virtual pixel layer that complicates encapsulation and frame thickness.
Innovation Solution
Control the solvent amount on the substrate by increasing it from the middle to the periphery of the ink layer, allowing for uniform solvent evaporation and omitting the virtual pixel layer to achieve a narrow frame.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the solution is printed on the display area by inkjet printing and the solvent is evaporated, then the film is formed, but the film thickness becomes non-uniform due to uneven solvent vaporization speed between middle and periphery portions
Solution Approach 1:
The patent applies local quality by printing different amounts of solvent at different positions within the display area. Specifically, the solvent amount is increased from the middle portion toward the periphery portion, creating a gradient distribution. This compensates for the faster evaporation rate at the periphery, ensuring uniform solvent concentration and film thickness across the entire display area after evaporation.
2Stability of the object's composition
If a virtual pixel layer is formed around the display area to extend the saturation area, then the solvent gas concentration becomes even, but the encapsulation area must be disposed around the virtual pixel layer, increasing the frame thickness
Solution Approach 1:
The patent extracts and eliminates the virtual pixel layer from the structure by directly controlling the solvent distribution within the display area through inkjet printing. By adjusting the solvent amount at different positions, the patent achieves uniform solvent gas concentration without requiring the additional virtual pixel layer, thereby removing the need for extended encapsulation areas and reducing frame thickness.
3Stability of the object's composition
If the solvent amount is increased at the periphery of the ink layer, then the solvent concentration becomes more uniform, but the total solvent amount increases
Solution Approach 1:
The patent applies parameter changes by modifying the solvent distribution pattern from a uniform amount to a gradient amount based on position. The solvent amount is systematically increased from the middle to the periphery, creating a controlled non-uniform distribution that compensates for evaporation differences. This optimized distribution achieves uniform concentration without excessive total solvent usage.
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 method ensures uniform film thickness and luminescence performance while enabling the production of narrow-frame OLED devices by maintaining even solvent concentration and volatilization rates across the display area.
Implementation Method 1
the solvent in a solution is evaporated by an evaporation process to form a film
Implementation Method 2
the shorter a distance between a middle portion of the substrate and a location where a solvent gas is volatilized, the higher a concentration of the solvent gas
Data Source
AI summary
The disclosure provides a method of manufacturing a display panel and a method of manufacturing a functional layer thereof. The method of manufacturing the functional layer includes following steps: forming an ink layer on a display area of a substrate by inkjet printing, wherein the ink layer includes a solute and a solvent configured to dissolve the solute, different positions of the ink layer have same amount of the solute, and an amount of the solvent in a periphery of the ink layer is greater than an amount of the solvent in a middle portion of the ink layer; and evaporating the solvent in the ink layer to form the functional layer with uniform thickness.