OLED Display Panel Green EBL Layout for Stable Charge Balance
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Solution Overview
Problem
Conventional OLED display devices face inefficiencies and reduced service life due to changes in the ratio of n-type to p-type host materials during evaporation deposition, leading to poor energy transfer and increased manufacturing costs from requiring separate chambers and fine metal masks for electron blocking and light emitting layers.
Innovation Solution
A display panel design using a p-type green light host material for the electron blocking layer, deposited in a single evaporation chamber with a fine metal mask, allowing for controlled mixing ratios and simplified manufacturing by eliminating the need for additional chambers and masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a red light premixed material is subjected to evaporation deposition process, then the light emitting layer can be formed, but the ratio of n-type host material to p-type host material changes as evaporation time goes by, resulting in low efficiency and shorter service life
Solution Approach 1:
The electron blocking layer is segmented into different material compositions for different sub-pixel regions. The green sub-pixel region uses p-type green light host material while other regions use conventional materials, allowing each region to be optimized independently for its specific function and color requirements
Solution Approach 2:
Different material types are applied to different locations based on local requirements. The green sub-pixel region specifically uses p-type host material to match the energy levels of green light emitting materials, while other regions use materials optimized for their respective colors and functions
2Manufacturing precision
If separate chambers and fine metal masks are used for depositing electron blocking layer and light emitting layer, then proper material deposition can be achieved, but manufacturing steps increase and production costs increase
Solution Approach 1:
The electron blocking layer and light emitting layer deposition processes are merged into a single evaporation chamber operation. By using a single fine metal mask with appropriately designed patterns, both layers can be deposited sequentially without requiring chamber evacuation and repositioning, thereby simplifying the manufacturing process
Solution Approach 2:
A single fine metal mask is designed to serve multiple functions: it defines the pattern for the electron blocking layer during its deposition, and subsequently serves as a template or barrier during the light emitting layer deposition in the same chamber, eliminating the need for separate masking operations
3Ease of manufacture
If conventional electron blocking layer materials are used, then the layer can be deposited, but the HOMO energy level is poorly matched with p-type host material, causing potential energy barrier to electron/hole migration and degradation of device performance
Solution Approach 1:
The HOMO energy level parameter of the electron blocking layer material is changed by selecting p-type green light host material instead of conventional materials. This parameter change ensures better energy level matching with the p-type host material in the green sub-pixel region, eliminating potential energy barriers for charge carrier migration
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 stabilizes the charge carrier balance, enhances device performance, and reduces production costs by maintaining consistent material ratios and simplifying the manufacturing process.
Implementation Method 1
when the red light premixed material is subjected to a evaporation deposition process
Data Source
AI summary
A display panel and manufacturing method thereof are provided. The display panel includes a substrate, a first electrode, a hole injection layer, a hole transport layer, an electron blocking layer, an organic electroluminescent layer, a hole blocking layer, an electron transport layer, an electron injection layer, and a second electrode arranged sequentially. The electron blocking layer corresponding to a green sub-pixel region of the organic electroluminescent layer is made of a p-type green light host material. Accordingly, the present invention effectively simplifies a manufacturing process, adjusts and balances charge carriers, and improves device performance.