OLED Bottom Electrode Thickness Segmentation for Angular Color Shift
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Solution Overview
Problem
Conventional OLED devices with micro-cavity structures suffer from reduced light emission efficiency and color shift issues when viewed from different angles due to the reflective metal layer, which affects the consistency of light intensity and wavelength.
Innovation Solution
The implementation of a bottom electrode with a thinner first portion and a thicker second portion in the organic electroluminescent multi-layer structure, creating distinct micro-cavity portions that provide wavelength shifts in different directions, thereby mitigating the micro-cavity effect and balancing color shift while increasing light intensity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a reflective metal layer is used in the OLED structure, then light emission efficiency is improved, but color shift occurs when viewed from different angles
Solution Approach 1:
The reflective electrode is segmented into multiple regions with different thicknesses (thinner first portion and thicker second portion) to create distinct micro-cavity portions. This segmentation allows different regions to compensate for each other's color shift, maintaining color consistency across various viewing angles while preserving light emission efficiency.
Solution Approach 2:
Different portions of the reflective electrode are given different local qualities (thicknesses) to serve different functions. The thinner first portion and thicker second portion create different optical path lengths that compensate for angular color shifts, allowing the structure to maintain both high reflectivity and color stability.
2Illumination intensity
If a micro-cavity structure is implemented, then emission is enhanced at a specific wavelength, but light intensity and wavelength vary at different viewing angles
Solution Approach 1:
The micro-cavity structure is segmented into multiple portions with different thicknesses, creating a distribution of optical resonances. This allows the structure to maintain enhanced emission intensity while reducing the angular dependence of wavelength, as different segments compensate for each other's angular color shifts.
Solution Approach 2:
The reflective electrode employs an asymmetric thickness profile (thinner first portion and thicker second portion) rather than a uniform thickness. This asymmetry creates complementary micro-cavity effects that balance out color shifts when viewed from different angles, maintaining both emission intensity and color consistency.
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 enhances light emission efficiency and maintains color consistency across various viewing angles by adjusting the proportion of the thicker second portion in the emission area, ensuring a closer alignment with pure white light within the color saturation range.
Implementation Method 1
In the micro-cavity structure, the emitting light may induce constructive and destructive interferences to enhance emission at a specific wavelength
Data Source
AI summary
An organic electroluminescent device is provided. The organic electroluminescent device includes an array substrate having a white sub-pixel region and an organic electro-luminescent multi-layer structure is disposed on the white sub-pixel region of the array substrate. The organic electro-luminescent multi-layer structure comprises a bottom electrode. The bottom electrode has a thinner first portion and a thicker second portion for providing a wavelength shift of light in different directions.