Blue OLED Non-Resonant Structure for Color Gamut and Process Margin
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Solution Overview
Problem
Current non-resonance structures in OLEDs fail to achieve high color characteristics for blue light-emitting devices, particularly in large displays, due to limitations in process margins and optical interference.
Innovation Solution
A blue light-emitting device with a non-resonant structure using a reflective electrode and a transmission electrode, featuring an intermediate layer with a blue light-emitting layer, where the distance between the reflective electrode and the light-emitting zone is adjusted to dissipate unnecessary light through destructive interference, enhancing color characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If a resonance structure is used in OLED to improve color characteristics, then color gamut and peak intensity are improved, but the process margin becomes extremely narrow (1%) making manufacturing difficult
Solution Approach 1:
The patent extracts and eliminates the resonance structure from the OLED device, removing the cavity formed by reflective electrodes and organic layers that caused the narrow process margin. By taking out the resonance mechanism, the device achieves color characteristics through alternative means (micro-cavity structure with specific optical path length) that are less sensitive to manufacturing variations.
Solution Approach 2:
The patent changes the optical parameters of the device by introducing a specific micro-cavity structure with controlled optical path length (L = (2n+1)λ/4). This parameter change allows the device to achieve resonance-like color enhancement without the stringent thickness control requirements of conventional resonance structures, thereby improving both color characteristics and process margin.
2Illumination intensity
If micro-cavity technology is used to increase color characteristics, then color gamut is improved, but the aperture ratio and device complexity increase
Solution Approach 1:
The patent merges the micro-cavity structure with the existing OLED architecture by integrating the reflective electrode and organic layers into a unified optical path length control system. This merging allows the device to achieve color enhancement through the combined optical path length (L) rather than requiring separate, complex cavity structures, thereby improving color gamut while managing device complexity.
Solution Approach 2:
The patent makes the organic layers and reflective electrodes serve dual functions: as functional components for electroluminescence and as optical elements for micro-cavity resonance. This multi-functionality eliminates the need for additional dedicated cavity structures, improving color gamut without proportionally increasing device complexity and aperture ratio.
3Measurement precision
If resonance structure is used to achieve high color characteristics, then FWHM is reduced and peak intensity is increased, but the thickness control requirement becomes extremely strict
Solution Approach 1:
The patent introduces an intermediary optical path length parameter (L) that mediates between the physical thickness of layers and the optical resonance condition. By controlling the optical path length rather than individual layer thicknesses, the device achieves narrow FWHM and high peak intensity while reducing the strictness of thickness control requirements through this intermediary parameter.
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 excellent color reproducibility and luminance characteristics, meeting sRGB blue standards, with improved manufacturing efficiency and reduced process complexity, enabling mass production of high-quality OLEDs.
Implementation Method 1
The organic light-emitting layer has a functional thin film form and is disposed between the anode and the cathode. In the OLED, a hole and an electron are injected into the organic light-emitting layer respectively from the anode and the cathode where they combine to form an exciton, which emits light.
Implementation Method 2
a reflective electrode facing the transparent electrode... dissipating light reflected at the reflective electrode
Data Source
AI summary
A blue light-emitting device, and an organic light-emitting display including the blue light-emitting device, has a non-resonance structure including a blue light-emitting layer between a reflective electrode and a transparent electrode, and thus has an excellent process margin, an excellent luminance characteristic even in a wide optical viewing angle, and a high color reproduction satisfying an sRGB blue standard.