OLED Light-Shielding Layer for Uniform Inkjet Printing
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Solution Overview
Problem
Inkjet printing of Organic Light-Emitting Diodes (OLEDs) faces issues with non-uniform light emission due to edge warping of the organic layer, caused by poor contact between hydrophobic bank materials and hydrophilic OLED ink, leading to inhomogeneous distribution and light leakage.
Innovation Solution
A light-emitting panel is manufactured with a structure that includes an ITO substrate, a light-emitting layer with alternately arranged isolation dam bodies and light-emitting bodies, and a thin light-shielding layer on a cover glass, where the light-shielding bodies are designed to match the size and position of the edge warp, ensuring uniform light emission by shielding non-uniform areas with a thickness less than 1 μm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If hydrophobic bank materials are used to define the light-emitting area, then the bank layer can effectively contain the OLED ink, but the poor contact between hydrophobic bank materials and hydrophilic OLED ink causes the ink to roll into grooves and form inhomogeneous distribution
Solution Approach 1:
The patent introduces a self-assembled monolayer (SAM) as an intermediary substance between the hydrophobic bank material and hydrophilic OLED ink. The SAM modifies the surface energy of the bank material to create optimal wettability, allowing the ink to spread uniformly without rolling into grooves. This mediator resolves the incompatibility between hydrophobic banks and hydrophilic ink.
Solution Approach 2:
The patent changes the surface energy parameter of the bank material by coating it with a self-assembled monolayer. This parameter modification transforms the extreme hydrophobicity of the bank material into optimal wettability, enabling uniform ink distribution while maintaining the bank's structural function of defining the light-emitting area.
2Object-affected harmful factors
If a thick light-shielding layer is used to block light leakage from metallic circuits, then light leakage is prevented, but the viewing angle and display performance are significantly affected
Solution Approach 1:
The patent applies local quality by positioning light-shielding bodies only at specific locations where metallic circuits are present, rather than using a uniform thick shielding layer across the entire display. This localized approach blocks light leakage from circuits while preserving viewing angle brightness in the light-emitting areas.
Solution Approach 2:
The patent uses partial action by implementing thin light-shielding bodies with specific optical properties that provide sufficient shielding against light leakage from metallic circuits while allowing adequate light transmission for normal display viewing. The shielding is applied only where necessary rather than excessively across the entire panel.
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 approach effectively improves the uniformity of light emission in OLEDs produced by inkjet printing, preventing light leakage and maintaining a wide viewing angle without significantly affecting the display's performance.
Implementation Method 1
a light-shielding layer on a cover glass... the light-shielding bodies are designed to match the size and position of the edge warp, ensuring uniform light emission by shielding non-uniform areas
Implementation Method 2
when a current flows through organic materials, these organic materials will emit light
Data Source
AI summary
Related to is the field of light-emitting panel manufacture, and a light-emitting panel and a method for manufacturing the same are provided, which aim to improve uniformity of light emission of an Organic Light-Emitting Diode (OLED) manufactured by Inkjet Printing (IJP). The light-emitting panel sequentially comprises an ITO substrate, a light-emitting layer, a light-shielding layer, and a cover glass. The method comprises forming a multilayer structure sequentially including an ITO substrate, a light-emitting layer, a light-shielding layer, and a cover glass. According to a size of an edge warp of a light-emitting area of the OLED, a light-shielding layer is designed at a corresponding position of the light-emitting area on the cover glass, and a position of a non-uniform edge is subjected to light-shielding processing, so that the problem of non-uniform light emission caused by the edge warp of the organic light-emitting layer is solved. A display part can thus be uniformly showed, thereby effectively improving the uniformity of light emission of the OLED manufactured by IJP.