OLED Emission Layer Mixed Host Deposition
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Solution Overview
Problem
Conventional organic light emitting display devices face challenges in controlling thickness and increasing manufacturing costs due to multilayer structures, which also lead to higher defect rates and complexity in microcavity and stack structures.
Innovation Solution
The use of a substrate with subpixels featuring an emission layer composed of a first host layer, a mixed layer made of a combination of first and second host materials and a dopant material, and a second host layer, where the thickness of each layer can be controlled to achieve a microcavity structure with reduced lamination and mask processes, utilizing a source deposition unit to deposit these layers in a single pass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a multilayer structure is used to achieve microcavity and stack structures, then light emission efficiency and color coordinates are improved, but manufacturing cost increases due to increased amount of materials and thickness
Solution Approach 1:
The patent combines multiple host materials (first host material and second host material) into a single mixed layer, eliminating the need for separate first host layer and second host layer. This merging reduces the total amount of materials required while maintaining the microcavity structure's light emission efficiency through the optimized mixed composition of host materials and dopant.
2Illumination intensity
If a multilayer structure is used to achieve microcavity and stack structures, then light emission efficiency and color coordinates are improved, but manufacturing cost increases due to increased number of processes and equipment
Solution Approach 1:
The patent merges the deposition processes for first host layer, second host layer, and dopant layer into a single process step where all components are deposited simultaneously to form the mixed layer. This reduces the number of deposition processes and eliminates the need for additional equipment chambers, thereby improving ease of manufacture while maintaining light emission efficiency.
3Illumination intensity
If a multilayer structure is used to achieve microcavity and stack structures, then light emission efficiency and color coordinates are improved, but defect rates increase due to increased number of fine metal masks
Solution Approach 1:
The patent combines the formation of first host layer, second host layer, and dopant layer into a single mixed layer deposition step, which reduces the number of fine metal masks required. This merging of layers into one deposition process minimizes the opportunities for defects that would otherwise occur during multiple separate deposition steps, thereby improving reliability while maintaining the optical performance.
4Manufacturing precision
If a multilayer structure is used to achieve microcavity structure, then thickness control becomes possible, but device complexity increases
Solution Approach 1:
The patent merges multiple layers (first host layer, second host layer, dopant layer) into a single mixed layer with controlled composition. This approach maintains the thickness control necessary for microcavity structure through precise control of the mixed layer's thickness and composition ratios, while simultaneously reducing device complexity by eliminating the need for multiple separate layer structures.
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 simplifies thickness control, reduces manufacturing costs, minimizes defect rates, and enhances light emission efficiency, power efficiency, and lifespan by using a smaller lamination structure and optimizing the deposition process.
Implementation Method 1
in the forming of the emission layer, a source deposition unit provided with first and second host sources respectively containing the first and second host materials and a dopant source containing the dopant material is used, and in the forming of the emission layer, deposition is performed
Data Source
AI summary
The present invention has been made in an effort to provide an organic light emitting display device comprising: a substrate; and subpixels formed on the substrate, each of the subpixels comprising an emission layer consisting of a first host layer made of a first host material, a mixed layer made of the first host material, a dopant material, and a second material, and a second host layer made of the second host material.