Display Device Charge Generation Layer Metal Work Function Optimization
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Solution Overview
Problem
Existing organic light emitting display devices face challenges in maintaining efficient display performance due to rising driving voltage and varying light emitting characteristics across different pixel areas, which affects display efficiency and speed.
Innovation Solution
The display device incorporates a base layer with distinct pixel areas emitting different lights, utilizing specific metals in charge generation layers and doping layers to optimize charge injection and transport, ensuring each light emitting stack operates within its designated light emitting range, thereby reducing driving voltage and enhancing display efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single charge generation layer material is used across all pixel areas, then device structure is simple, but display efficiency decreases due to mismatched characteristics across different light emitting ranges
Solution Approach 1:
The patent applies local quality by using different metal materials in charge generation layers for different pixel areas. Specifically, a first metal is used in the first pixel area and a second metal is used in the second pixel area, allowing each region to have optimized charge generation characteristics matched to its light emitting requirements, thereby improving display efficiency without excessive complexity
2Device complexity
If conventional organic light emitting elements are used, then device structure is simple, but driving voltage rises and display efficiency decreases
Solution Approach 1:
The patent applies parameter changes by carefully selecting metal materials with specific work function ranges for charge generation layers. The first metal has a work function of 1.7-3.2 eV and the second metal has a work function of 2.0-3.5 eV, optimizing charge injection and transport parameters to reduce driving voltage while improving display efficiency
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 allows for improved display efficiency by matching device characteristics with light emitting ranges, reducing driving voltage and preventing delays, enabling high-speed operation and efficient light emission across different pixel areas.
Implementation Method 1
the second metal has a work function equal to or greater than about 1.7 eV and equal to or smaller than about 3.2 eV
Data Source
AI summary
A display device including a base layer including a first pixel area configured to emit a first light therefrom and a second pixel area configured to emit a second light therefrom, a first electrode on the base layer, a second electrode on the first electrode and facing the first electrode, first light emitting stacks between the first and second electrodes and in the first pixel area, a first charge generation layer between the first light emitting stacks, second light emitting stacks between the first and second electrodes and in the second pixel area, and a second charge generation layer between the second light emitting stacks. The first charge generation layer includes a first metal, the second charge generation layer includes a second metal different from the first metal, and the second metal has a work function equal to or greater than 1.7 eV and equal to or smaller than 3.2 eV.