OLED Shadow Emission Layer Removal for Light Efficiency
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Solution Overview
Problem
The existing organic light emitting display apparatuses face challenges in controlling deposition processes, leading to limitations in improving light emission characteristics due to the formation of undesired shadow emission layers, which affect the efficiency of the organic emission layers.
Innovation Solution
The proposed solution involves an organic light emitting display apparatus with sub-pixels that include a shadow emission layer between the organic emission layer and the first electrode, where the organic emission layer contains a hole transport material, and a multi-layered hole transport layer, formed using an organic layer deposition apparatus with a specific deposition process that allows for non-uniform thickness and slanted sides, enhancing light emission efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a deposition mask is used to form intermediate layers including organic emission layer, then a predetermined pattern can be formed, but it is difficult to control the deposition process and form deposition films with good light emission characteristics
Solution Approach 1:
The patent extracts and removes the shadow emission layer that forms between the organic emission layer and the first electrode. This shadow emission layer is formed during the deposition process and causes abnormal light emission. By removing this harmful layer, the patent improves light emission characteristics while maintaining the deposition mask method for pattern formation.
Solution Approach 2:
The patent changes the deposition process parameters, specifically forming the organic emission layer with a controlled thickness of 50-200 nm and using specific deposition conditions to prevent excessive shadow emission layer formation. This parameter optimization allows good light emission characteristics to be achieved while maintaining pattern formation precision.
2Manufacturing precision
If shadow emission layer is formed during deposition process, then deposition pattern can be created, but abnormal light emission occurs and light emission efficiency is reduced
Solution Approach 1:
The patent converts the harmful shadow emission layer into a beneficial structure by controlling its thickness and composition. Instead of completely eliminating the shadow emission layer, the patent optimizes it to emit desirable light while preventing abnormal emission, thus converting a harmful effect into a useful one for improving overall light emission efficiency.
Solution Approach 2:
The patent applies different properties to different regions of the intermediate layer. The organic emission layer is formed with specific hole transport materials and thickness in regions where good light emission is needed, while the shadow emission layer is controlled or removed in regions where it causes abnormal emission. This local quality differentiation optimizes light emission efficiency while maintaining pattern formation.
3Ease of manufacture
If conventional deposition process is used to form intermediate layers, then manufacturing process can be completed, but light emission characteristics cannot be improved
Solution Approach 1:
The patent modifies deposition process parameters including organic emission layer thickness (50-200 nm), deposition rate, and temperature control to improve light emission characteristics while maintaining ease of manufacture. These parameter changes are integrated into the existing deposition process, allowing good light emission to be achieved without fundamentally changing the manufacturing workflow.
Solution Approach 2:
The patent uses composite materials in the organic emission layer, combining hole transport materials with specific emission materials to create an intermediate layer that provides both ease of deposition and improved light emission characteristics. This composite approach allows the manufacturing process to remain simple while achieving superior optical performance.
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 configuration improves the light emission efficiency of the organic light emitting display apparatus by reducing abnormal light emission from the shadow emission layer and optimizing the light emission characteristics of the red, green, and blue sub-pixels, while also reducing the driving voltage.
Implementation Method 1
When a voltage is applied to the first and second electrodes, the organic emission layer generates visible rays
Implementation Method 2
The intermediate layer may be formed by using an organic layer deposition apparatus
Data Source
AI summary
An organic light emitting display apparatus including a plurality of sub-pixels disposed on a substrate, wherein each of the sub-pixels includes: a first electrode formed on the substrate; an intermediate layer formed on the first electrode and including an organic emission layer; and a second electrode formed on the intermediate layer, wherein at least one sub-pixel for emitting light of a color among the sub-pixels includes a shadow emission layer for emitting light of different color between the organic emission layer and the first electrode, and the organic emission layer of the one sub-pixel includes a hole transport material.