Pixel Define Layer Preparation for Residue-Free OLED Pixels
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Solution Overview
Problem
Existing organic light emitting display devices face issues with residues causing dark spots and pixel shrinkage due to incomplete removal during the developing step, and high outgas levels leading to reduced luminance and lifetime, necessitating improved methods for forming pixel defining layers.
Innovation Solution
A method involving a photosensitive composition with optimized developing and post-baking steps, including specific temperature and time ranges, to minimize residues and outgas, using a photosensitive composition with inorganic and organic pigments, and a binder resin, to form a pixel defining layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If coloring patterns with organic pigments are used to achieve vivid colors, then color quality is improved, but outgas increases causing pixel shrinkage and dark spots
Solution Approach 1:
The patent optimizes the developing temperature and time parameters to precisely control the removal of photoresist while minimizing outgas generation. By setting developing temperature to 19-27°C and time to 30-90 seconds, the process achieves complete residue removal without excessive outgas that would cause pixel shrinkage
Solution Approach 2:
The patent implements a pre-baking step before the developing process to pre-treat the photoresist layer. This preliminary action prepares the photoresist for optimal developing performance, ensuring complete removal without requiring aggressive developing conditions that would generate harmful outgas
2Manufacturing precision
If developing time and temperature are increased to remove residues, then pixel cleanliness is improved, but outgas increases causing pixel shrinkage
Solution Approach 1:
The patent establishes specific parameter ranges for developing (19-27°C for 30-90 seconds) that optimize the balance between residue removal and outgas control. These precisely controlled parameters ensure complete pixel cleanliness while limiting outgas to 110 ppm or less, preventing pixel shrinkage
Solution Approach 2:
The patent uses outgas measurement as a feedback parameter to monitor and control the developing process. By measuring outgas levels during development, the process can be adjusted in real-time to maintain pixel cleanliness while preventing excessive outgas accumulation that would cause shrinkage
3Reliability
If post-baking temperature and time are increased to reduce outgas, then pixel shrinkage is prevented, but processing time and energy consumption increase
Solution Approach 1:
The patent implements pre-baking before developing to pre-treat the photoresist layer, reducing the outgas potential before the main developing process. This preliminary action allows for milder post-baking conditions, reducing both processing time and energy consumption while still preventing pixel shrinkage
Solution Approach 2:
The patent optimizes post-baking parameters (210-300°C for 30-120 minutes) to achieve the minimum effective treatment for outgas reduction. By finding the optimal parameter range, the process prevents pixel shrinkage while minimizing unnecessary processing time and energy consumption
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 method results in residue-free pixels and reduced outgas, enhancing display reliability and lifespan by minimizing dark spots and pixel shrinkage, while maintaining vivid colors.
Implementation Method 1
A method involving a photosensitive composition with optimized developing and post-baking steps
Implementation Method 2
the amount of outgas generated in the panel is 110 ppm or less
Data Source
AI summary
An object of the present disclosure is to improve display reliability and lifetime as well as vivid colors. When there remain residues in the washing part due to incomplete removal during the developing step, it can cause dark spots or pixel off due to the residues, and thus residue-free pixels can be formed by optimizing the temperature and time for developing. Additionally, when the amount of outgas in the panel after post-baking is 15 ppm or more, it may cause a reduction in luminance and lifetime due to pixel shrinkage. Therefore, in order to minimize the amount of outgas after completion of the post-baking process, the generation of outgas in the panel state can be minimized by generating sufficient fume in the post-baking step, in addition to forming clean pixels in the developing step.