Functional Layer Ink Particle Control for OLED Yield
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Solution Overview
Problem
The challenge in manufacturing organic electro-luminescence elements is the inclusion of foreign particles in the ink, which leads to defects in the functional layers, particularly when the pixel size becomes finer, resulting in reduced yield and luminescent performance.
Innovation Solution
Developing an ink for forming functional layers with controlled particle sizes, where the number of particles 0.5 μm or more is limited to 7 or less in 10 ml, and using a method to select and filter the ink with a suitable filter hole diameter based on particle size measurements to minimize defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the pixel size is reduced to achieve finer display, then the resolution is improved, but the impact of foreign particles increases leading to more defects
Solution Approach 1:
The patent applies preliminary action by filtering the ink solution before the coating process to remove foreign particles. The filtering step is performed in advance on the luminescence ink composition to ensure that when the ink is later applied to form fine-pixel layers, foreign particles are already removed, preventing defects in the final high-resolution display.
2Reliability
If conventional filtering methods are used, then some particles are removed, but the number of particles 0.5 μm or more remains too high for fine pixels
Solution Approach 1:
The patent applies parameter changes by specifying precise filtering parameters: the ink must be filtered to reduce particles of 0.5 μm or more to 5 or fewer per 10 ml. This quantitative parameter control ensures that the filtering process achieves the necessary level of cleanliness for fine-pixel manufacturing, transforming the vague concept of 'particle removal' into a measurable and controllable parameter.
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 enables the formation of thin film layers with reduced defects, improving the yield and luminescent performance of organic electro-luminescence elements by ensuring minimal foreign particles, thus enhancing the manufacturing process efficiency.
Implementation Method 1
a method of manufacturing an ink for forming a functional layer which is used when any thin film layer among functional layers consisting of a plurality of thin film layers is formed, including measuring the size and the number of particles included in the ink for forming a functional layer per unit volume after mixing, selecting a hole diameter of a filter based on a result of the measuring, and filtering the ink for forming a functional layer using a filter having a hole diameter selected in the selecting
Data Source
AI summary
An ink for forming a functional layer, which is used when any thin film layer among functional layers consisting of a plurality of thin film layers is formed, includes a functional layer forming material and a solvent for dissolving the functional layer forming material, and in which the number of particles of 0.5 μm or more is 7 or less in 10 ml of the ink for forming a functional layer.