Photoresist Patterning for High-Resolution OLED Pixel Definition
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Solution Overview
Problem
Existing methods for manufacturing light-emitting display devices face challenges in forming high-resolution displays with accurate color separation between adjacent pixels, leading to potential color mixing and reduced display quality due to the flow of light-emitting solutions during the formation of hole injection, hole transport, and light-emitting layers.
Innovation Solution
A method involving the use of photoresist patterns and a lift-off process to precisely form and remove layers on specific pixel areas, combined with tilting the substrate to control solution distribution and prevent unwanted layer formation on adjacent pixels, ensuring accurate color separation and high-resolution display.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If light-emitting solution is applied to form layers on pixels, then the light-emitting layers are formed, but the solution flows to adjacent pixels causing color mixing
Solution Approach 1:
A photoresist pattern is formed on the substrate before applying the light-emitting solution. This photoresist pattern serves as a protective layer that prevents the solution from flowing onto adjacent pixels, thereby preventing color mixing while allowing the light-emitting layers to be formed on the intended pixels
Solution Approach 2:
The photoresist pattern acts as an intermediary protective layer between the light-emitting solution and the adjacent pixels. It selectively allows the solution to be applied only to the desired pixel areas while blocking the solution from reaching adjacent pixels, thus preventing color mixing
2Manufacturing precision
If photoresist pattern is used to prevent solution flow, then color mixing is prevented, but the manufacturing process becomes more complex
Solution Approach 1:
The photoresist pattern is formed using a printing method that automatically defines the pixel boundaries and protects adjacent pixels during the light-emitting layer formation process. The pattern serves multiple functions: it acts as a mask during solution application and is subsequently removed through a lift-off process, integrating protection and patterning in a single systematic approach
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 enhances display quality by preventing color mixing and enabling the production of high-resolution light-emitting display devices with improved pixel accuracy and color separation.
Implementation Method 1
The removing of the first photoresist pattern may be performed using a lift-off process.
Implementation Method 2
The forming of the light-emitting layer may include ejecting a light-emitting solution onto the first electrode of each of the first pixels and then drying the ejected light-emitting solution
Implementation Method 3
The forming of the light-emitting layer may include ejecting a light-emitting solution onto the first electrodes of some of the first pixels and tilting the substrate to cause the light-emitting solution to flow onto the first electrode of other ones of the first pixels
Data Source
AI summary
Provided is a method of manufacturing a light-emitting display device. The method of manufacturing a light-emitting display device may comprise: forming a first electrode on a substrate, the substrate having a plurality of first pixel areas and a plurality of second pixel areas, the first electrode being formed in each of the first and second pixel areas such that corresponding first and second pixels are formed; forming a pixel defining layer on the substrate, the pixel defining layer having an opening exposing the first electrode of each of the first and second pixels; forming a first photoresist pattern on the pixel defining layer, the first photoresist pattern having a first pattern opening exposing the first electrode of each of the first pixels; forming a light-emitting layer on the first electrode exposed through the first pattern opening; and removing the first photoresist pattern.