Organic Light-Emitting Display Light Control Layer
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Solution Overview
Problem
Organic light-emitting displays face efficiency issues due to light reflection at the interface between the anode and the substrate, resulting from refractive index differences, which reduces luminous efficacy.
Innovation Solution
Incorporating a light control layer structure with alternately stacked low and high refractive index layers between the anode and the substrate, which reduces refractive index differences and minimizes light reflection, thereby enhancing light transmission and efficacy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a light control layer structure with alternately stacked low and high refractive index layers is added between the anode and substrate, then light transmission efficiency is improved, but device complexity increases
Solution Approach 1:
A light control layer structure consisting of alternately stacked low refractive index layers and high refractive index layers is introduced as an intermediary between the anode and substrate. This multi-layer structure acts as an optical mediator that gradually transitions the refractive index, thereby reducing light reflection at the anode-substrate interface and improving light extraction efficiency.
Solution Approach 2:
The light control layer structure employs composite material design by stacking multiple layers with different refractive indices (low refractive index layers and high refractive index layers). This composite structure creates an optimized optical pathway that minimizes reflection losses while managing the added structural complexity through systematic material arrangement.
2Use of energy by moving object
If the light control layer structure is implemented, then luminous efficacy is improved, but manufacturing complexity increases
Solution Approach 1:
The light control layer structure is segmented into multiple discrete layers with alternating low and high refractive indices. This segmentation allows for systematic fabrication where each layer can be deposited separately using standard thin-film techniques, making the complex structure manageable in terms of manufacturing processes.
Solution Approach 2:
The invention utilizes parameter changes in refractive index by selecting materials with specific refractive index values for the alternating layers. By controlling this optical parameter across multiple layers, the structure achieves optimized light extraction and improved luminous efficacy while maintaining compatibility with existing manufacturing capabilities.
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 implementation of the light control layer structure significantly improves the luminous efficacy and brightness of blue and yellowish-green light emission by reducing light reflection at the anode-substrate interface, as demonstrated in test examples with increased brightness and efficiency compared to devices without this structure.
Implementation Method 1
light generated by the light-emitting layer is reflected at an interface between the anode and the substrate toward the cathode due to a refractive index difference therebetween
Implementation Method 2
a light control layer structure including at least one pair of an alternately stacked low refractive index layer and high refractive index layer
Data Source
AI summary
An organic light-emitting display device includes: a substrate, light-emitting elements on the substrate, and a light control layer structure between an anode of each of the light-emitting elements and the substrate, the light control layer structure including at least one pair of an alternately stacked low refractive index layer and high refractive index layer, a lowest high refractive index layer contacting an upper surface of the substrate.