Organic EL Panel with Segmented Hole-Transporting Layers
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Solution Overview
Problem
Existing organic electroluminescent (EL) devices face challenges in achieving low power consumption and extended lifespan for mobile applications, requiring increased luminous efficiency and reduced drive voltage, while also needing cost reduction for competition with liquid crystal displays.
Innovation Solution
A full-color organic electroluminescent panel with red, green, and blue pixels that share a common hole-injecting layer and have distinct hole-transporting layers, optimized for each color, enhancing luminous efficiency and temporal stability through interference effects and the use of phosphorescent materials for reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a common hole-injecting layer is used for all color pixels, then manufacturing complexity is reduced and cost is decreased, but achieving optimal luminous efficiency and temporal stability for each color becomes more difficult
Solution Approach 1:
The hole-transporting layer is segmented into color-specific sections (red, green, blue) with different materials or thicknesses, while the hole-injecting layer remains common. This segmentation allows each color pixel to have optimized hole transport properties without requiring separate hole-injecting layers, thus maintaining manufacturing simplicity while achieving color-specific temporal stability.
Solution Approach 2:
Different regions of the hole-transporting layer are given different local qualities (materials or thicknesses) matched to each color pixel's requirements. The red pixel region has hole-transporting properties optimized for red emission, green for green, and blue for blue, while sharing the common hole-injecting layer structure.
2Device complexity
If color filters are used to produce full-color images, then device structure is simplified, but light loss increases and luminance decreases
Solution Approach 1:
Instead of using white light emission with color filters (which blocks most light), the patent inverts the approach by using direct color emission from the organic EL devices themselves. Each pixel emits its primary color directly through optimized hole-transporting layers, eliminating the need for color filters and maximizing luminance while simplifying the overall device structure.
3Use of energy by moving object
If drive voltage is reduced to lower power consumption, then energy efficiency improves, but device life time and reliability may be affected
Solution Approach 1:
The patent changes material parameters (hole-transporting layer materials and thicknesses) to optimize hole injection and transport efficiency. This allows the device to operate at lower drive voltages with sufficient current efficiency, reducing power consumption while maintaining stable operation and extending device lifetime through improved material selection and layer optimization.
4Reliability
If separate hole-transporting layers are used for each color pixel, then luminous efficiency and temporal stability for each color are optimized, but manufacturing complexity and cost increase
Solution Approach 1:
The patent merges the hole-injecting layer into a single common structure for all color pixels, while maintaining separate optimized hole-transporting layer sections for each color. This combining approach reduces the total number of layers and manufacturing steps compared to having completely separate structures for each color, while still achieving color-specific optimization for luminous efficiency and temporal stability.
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
The solution achieves low power consumption and excellent temporal stability in light emission for all color pixels, extending device lifespan and reducing costs, while maintaining high luminance and efficiency.
Implementation Method 1
Organic EL devices emit light when supplied with current from a power supply disposed outside a display region where the devices are arranged
Implementation Method 2
the use of phosphorescent materials for reduced power consumption
Data Source
AI summary
A full-color organic electroluminescent panel has red (R), green (G), and blue (B) color pixels that independently emit light. The organic electroluminescent panel includes a hole-injecting layer common to the red (R), green (G), and blue (B) color pixels and a plurality of hole-transporting layers. The hole-transporting layer in at least one of the red (R), green (G), or blue (B) color pixels differs from a corresponding hole-transporting layer in the remaining pixels.