QLED Display Panel Scattering Layer for Top-Emission Light Extraction
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Solution Overview
Problem
In QLED display products, top emission structures with metal thin film electrodes suffer from low transmissivity and complex light extraction efficiency due to microcavity effects, limiting light emergent efficiency.
Innovation Solution
A display panel design featuring a transparent second electrode and a scattering layer with a rough surface (RMS roughness of 50 nm to 200 nm) is used, enhancing light emergent efficiency by scattering and refracting light, and a two-layer electrode structure with a high-transmissivity third electrode is implemented to reduce resistance and improve performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a metal thin film electrode is used in a top emission QLED structure, then the electrode provides good electrical conductivity, but the transmissivity is low and light extraction efficiency is reduced due to microcavity effects
Solution Approach 1:
The patent extracts the light extraction function from the metal electrode by introducing a separate scattering layer. The metal electrode is replaced with a transparent electrode, and the scattering layer is added to handle light extraction, thereby resolving the conflict between electrical conductivity and light transmission.
Solution Approach 2:
The scattering layer acts as an intermediary between the transparent electrode and the external environment. It mediates the light extraction process by scattering light effectively while allowing the transparent electrode to maintain its electrical function without optical interference.
2Ease of manufacture
If a smooth surface is used on the scattering layer, then the manufacturing process is simpler, but total reflection occurs and light extraction efficiency is limited
Solution Approach 1:
The patent applies surface curvature by creating a rough surface with controlled RMS roughness (50-200 nm). This microscopic curvature scattering centers throughout the scattering layer, transforming the smooth planar surface into one with effective light scattering capability while maintaining manufacturing feasibility.
Solution Approach 2:
The patent changes the surface parameter by controlling the RMS roughness within a specific range (50-200 nm). This parameter optimization ensures effective light scattering without excessive manufacturing complexity, balancing optical performance with ease of fabrication.
3Loss of energy
If a transparent electrode is used instead of a metal thin film, then transmissivity is improved, but electrode resistance increases
Solution Approach 1:
The patent employs a composite electrode structure combining transparent conductive oxide (TCO) materials with metal nanoparticles or multi-layer configurations. This composite approach maintains high transmissivity while improving electrical conductivity through the synergistic combination of materials with complementary properties.
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 significantly increases light emergent efficiency and display effect by preventing total reflection and enhancing refraction, while maintaining high transmissivity and reducing electrode resistance.
Implementation Method 1
A display panel design featuring a transparent second electrode and a scattering layer with a rough surface (RMS roughness of 50 nm to 200 nm) is used, enhancing light emergent efficiency by scattering and refracting light
Implementation Method 2
enhancing light emergent efficiency by scattering and refracting light
Data Source
AI summary
The present disclosure relates to a display panel, a method for preparing the same and a display device. The display panel includes a first electrode, a light emitting structure, a second electrode and a scattering layer stacked in sequence. The second electrode is a transparent electrode. One side of the scattering layer away from the second electrode is configured as a light emergent side. The surface of the one side of the scattering layer away from the second electrode is a rough surface, and the RMS of the roughness of the rough surface ranges from 50 nm to 200 nm.