OLED Micro Lens Recesses Redirect Light to Prevent Leakage
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Solution Overview
Problem
Organic light emitting diode (OLED) display devices suffer from low light extraction efficiency due to total reflection and absorption by the anode electrode and substrate, resulting in significant light loss, with existing solutions like micro lens arrays and micro lenses failing to adequately address this issue and often causing light leakage.
Innovation Solution
The OLED display device incorporates a polarizing plate, a substrate with an overcoating layer featuring micro lenses with recesses and protrusions, and a reflective pattern positioned within the recesses, which redirects light incident at angles greater than the total reflection threshold to enhance light extraction and prevent light leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a micro lens array or micro lens is introduced to improve light extraction efficiency, then light extraction efficiency is improved, but light leakage occurs and reflectivity increases
Solution Approach 1:
The overcoating layer is designed with different local structures: micro lenses in emission areas for light extraction enhancement, and recesses in non-emission areas for light blocking. This local differentiation allows each region to perform its specific function optimally without causing light leakage or increased reflectivity.
Solution Approach 2:
The overcoating layer is segmented into multiple functional regions: emission areas with micro lenses for light extraction, non-emission areas with recesses for light blocking, and reflective patterns in recesses to redirect oblique light. This segmentation enables precise control of light paths in different areas.
2Loss of energy
If light is redirected at angles greater than total reflection threshold, then light extraction efficiency is improved, but light may reach adjacent pixels causing light leakage
Solution Approach 1:
The recesses act as intermediary structures between the micro lenses in emission areas and adjacent pixels. They provide a physical barrier and light-blocking region that prevents obliquely redirected light from reaching adjacent pixels, while still allowing effective light extraction from the intended emission areas.
Solution Approach 2:
The reflective patterns disposed in the recesses convert potentially harmful oblique light that would cause light leakage into beneficially redirected light that is reflected back toward the emission area or absorbed by the reflective pattern, thereby preventing light leakage while maintaining extraction efficiency.
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
This configuration significantly improves light extraction efficiency by redirecting light that would otherwise be lost, reducing external reflectivity and preventing light leakage, thereby enhancing the overall brightness and efficiency of the OLED display.
Implementation Method 1
redirects light incident at angles greater than the total reflection threshold
Implementation Method 2
micro lenses with recesses and protrusions
Data Source
AI summary
Provided is an organic light emitting diode display device. The organic light emitting diode display device includes a polarizing plate, a substrate disposed on the polarizing plate, an overcoating layer disposed on the substrate and including a plurality of micro lenses, and a first electrode, an organic emission layer, and a second electrode of an organic emission element which is disposed on the overcoating layer, in which the micro lens includes a plurality of recesses and a wall surrounding the recesses and a reflective pattern is disposed in an area corresponding to the recess.