Light Emitting Display Nano-Layer Light Extraction
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Solution Overview
Problem
In light emitting displays, about 50% of generated light is trapped due to optical wavelength formation between high refractive index transparent conductive layers and emission layers, leading to reduced light emission towards the user, and existing solutions fail to efficiently address this issue while maintaining low manufacturing costs and power consumption.
Innovation Solution
A light emitting display structure incorporating a nano-layer with indium-tin-oxide or indium-zinc-oxide nano-particles and a reflective layer under the anode electrode, which enhances light extraction efficiency without additional nano-material forming processes, allowing for higher luminance with reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If transparent conductive layers with high refractive index are used for anode and cathode electrodes, then electrical conductivity and transparency are improved, but light extraction efficiency deteriorates due to optical wavelength formation and total internal reflection
Solution Approach 1:
A reflective layer is introduced as an intermediary component between the emission layer and the transparent conductive cathode electrode. This reflective layer serves as a mediator that redirects trapped light waves away from the high refractive index interface, preventing total internal reflection while maintaining the electrical and optical properties of the transparent conductive electrodes.
Solution Approach 2:
The cathode electrode structure is segmented into multiple functional layers: a transparent conductive layer for electrical conductivity and transparency, and a separate reflective layer for light management. This segmentation allows each layer to optimize its specific function without compromising the others, resolving the contradiction between maintaining high refractive index benefits and reducing light trapping.
2Ease of manufacture
If conventional flat electrode structures are used, then manufacturing is simple, but light extraction efficiency is poor due to total internal reflection at glass-air interface
Solution Approach 1:
The reflective layer is merged with the existing electrode structure, combining light reflection functionality with the cathode electrode assembly. This integration approach enhances light extraction efficiency without requiring separate manufacturing processes or additional complex steps, maintaining ease of manufacture while improving optical performance.
3Loss of energy
If light extraction efficiency is improved by reducing refractive index differences, then light emission increases, but electrical conductivity of transparent conductive layers must be compromised
Solution Approach 1:
The reflective layer acts as an intermediary that enables light extraction enhancement without requiring changes to the transparent conductive layers' refractive indices or material compositions. This mediator approach allows the transparent conductive layers to maintain their optimal electrical conductivity and transparency properties while the reflective layer handles the light management function.
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 proposed structure significantly improves light extraction efficiency, reduces manufacturing costs, and achieves higher luminance with lower power consumption by uniformly distributing nano-structures across the display.
Implementation Method 1
a reflective layer between the buffer layer and the anode electrode
Implementation Method 2
a nano layer on the buffer layer; the nano layer includes: first nano-particles having a first size; and second nano-particles having a second size smaller than the first size
Data Source
AI summary
The present disclosure relates to a light emitting display in which the light extracting efficiency is improved by using nano patterns (or nano particles). A light emitting display includes a substrate including a first pixel and a second pixel. The light emitting display includes a buffer layer on the substrate. The light emitting display includes a nano layer on the buffer layer. The light emitting display includes an anode electrode on the nano layer. The light emitting display includes a reflective layer between the buffer layer and the anode electrode.