OLED Base Substrate with Gradient Polymer Light Outcoupling Layer
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Solution Overview
Problem
Conventional top-emission type OLEDs have low light outcoupling efficiencies, with approximately 80% of emitted light being lost due to trapping in surface plasmon polariton and waveguide modes, and existing surface corrugation techniques are expensive and unsuitable for generating regular patterns, leading to pixel blurring effects.
Innovation Solution
A base substrate with a light outcoupling layer featuring a corrugated surface formed by a polymer material with a gradient distribution, where the hydrophobic polymer content decreases and hydrophilic cross-linking density increases from the corrugated surface to the support substrate, enhancing light extraction and reducing pixel blurring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional surface corrugation techniques are used to improve light extraction, then light outcoupling efficiency is improved, but manufacturing cost increases and pixel blurring occurs
Solution Approach 1:
The patent applies local quality by creating a light outcoupling layer with a gradient distribution of polymer material density. The layer has higher polymer concentration near the corrugated surface and lower concentration toward the support substrate, allowing different regions to serve different functions: the surface region extracts light effectively while the deeper regions maintain structural integrity and prevent pixel blurring.
Solution Approach 2:
The patent uses composite materials by combining polymer materials with specific refractive indices in a gradient distribution within the light outcoupling layer. This composite structure with varying material composition enables simultaneous optimization of light extraction efficiency and manufacturing feasibility, avoiding the need for expensive conventional corrugation techniques.
2Loss of energy
If surface corrugation is introduced to enhance light extraction, then light outcoupling efficiency improves, but pixel definition precision deteriorates due to pixel blurring
Solution Approach 1:
The gradient distribution of polymer material creates local quality variations where the surface region optimizes light extraction while deeper regions maintain sharp pixel boundaries. The decreasing polymer concentration toward the substrate prevents excessive light scattering that would cause pixel blurring.
Solution Approach 2:
The patent transitions from two-dimensional surface corrugation to a three-dimensional gradient structure within the light outcoupling layer. This volumetric gradient in polymer concentration provides an additional dimension for controlling light extraction while maintaining pixel definition, avoiding the pixel blurring associated with conventional surface-only approaches.
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
Significantly increases light outcoupling efficiency and external quantum efficiency while reducing surface plasmon polariton loss and pixel blurring, achieving enhanced image brightness and reduced power consumption.
Implementation Method 1
a light outcoupling layer on the support substrate for enhancing light outcoupling efficiency of an organic light emitting display substrate
Implementation Method 2
approximately 80% of emitted light being lost due to trapping in surface plasmon polariton and waveguide modes
Implementation Method 3
the polymer material comprises a hydrophobic polymer material having a gradient distribution such that a content of the hydrophobic polymer material decreases in the direction from the corrugated surface to the support substrate
Data Source
Figure 1
Figure 2~3
Figure 4A~4B
AI summary
An organic light emitting diode base substrate (100) includes a support substrate (101) and a light outcoupling layer (102) on the support substrate (101) for enhancing light outcoupling efficiency of an organic light emitting display substrate, the light outcoupling layer (102) having a corrugated surface (20) on a side of the light outcoupling layer (102) distal to the support substrate (101). The light outcoupling layer (102) includes a polymer material having a gradient distribution in a direction from the corrugated surface (20) to the support substrate (101).