OLED Light-Extraction Substrate with Porous Scattering Layer
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Solution Overview
Problem
Organic light-emitting devices (OLEDs) suffer from low light extraction efficiency, with only about 20% of generated light being emitted due to inherent structural limitations, necessitating improved internal light extraction methods to utilize the remaining 80% of lost light.
Innovation Solution
A light extraction substrate comprising a base substrate with a porous light-scattering layer and a planarization layer, where scattering structures are formed by infiltrating a second material into the light-scattering layer to fill at least 5% of the holes, creating voids and varying refractive indices to enhance light scattering.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If an internal light extraction layer is used to extract light lost in optical waveguide mode, then light extraction efficiency is improved, but device complexity increases due to additional layer structure
Solution Approach 1:
The patent combines the light scattering function and planarization function into a single integrated layer structure. The planarization layer is formed to have a refractive index different from the light-scattering layer, creating scattering structures at the interface without requiring separate components. This merging reduces device complexity while maintaining high light extraction efficiency.
Solution Approach 2:
The planarization layer serves multiple functions: it provides surface planarization for subsequent electrode layer formation and simultaneously acts as a light scattering element through its refractive index difference with the light-scattering layer. This multi-functionality eliminates the need for additional dedicated scattering structures, reducing overall device complexity.
2Productivity
If scattering structures are formed by infiltrating material into light-scattering layer holes, then light scattering is enhanced, but manufacturing precision requirements increase
Solution Approach 1:
The patent utilizes a porous light-scattering layer with pre-formed holes as a template for creating scattering structures. The infiltration process fills these existing pores with a different material, creating refractive index variations that enhance light scattering. This approach leverages the inherent porosity rather than requiring precise fabrication of complex scattering structures.
Solution Approach 2:
The infiltration process automatically forms scattering structures by utilizing the capillary action and self-assembly of the second material into the porous structure. The process self-regulates to fill the holes uniformly without requiring complex external control mechanisms, reducing manufacturing precision requirements while achieving consistent light scattering enhancement.
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 enhances light extraction efficiency by maximizing the scattering of light, achieving 1.9 to 2.3 times the efficiency of existing methods, with uniform distribution of scattering structures and voids improving the formation of electrode layers.
Implementation Method 1
a porous light-scattering layer formed on the base substrate, including a first material, and having a plurality of holes formed therein
Implementation Method 2
a plurality of scattering structures including the second material, and formed by the second material infiltrated from the planarization layer into the light-scattering layer
Implementation Method 3
at least a part of the plurality of scattering structures has voids formed therein
Data Source
AI summary
Various aspects of an OLED and related methods of manufacturing are provided, wherein a light extraction substrate of an OLED includes a base substrate; a porous light-scattering layer, including a first material, and having a plurality of holes formed therein; a planarization layer formed on the light-scattering layer, and including a second material; and a plurality of scattering structures including the second material, and formed by the second material infiltrated from the planarization layer into the light-scattering layer to fill at least a part of the plurality of holes, the scattering structures including a plurality of second scattering structures.