OLED Micro Lens Overcoat Light Extraction
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Solution Overview
Problem
Organic light-emitting diode (OLED) display devices face reduced light extraction efficiency due to total internal reflection at interfaces between components, leading to decreased luminance and increased power consumption.
Innovation Solution
Incorporating micro lenses in the overcoat layer of OLED display devices, specifically arranged in the emission areas of sub-pixels with varying configurations to redirect and extract light that would otherwise be lost, including a flat portion for outermost sub-pixels to prevent electrical short circuits and bright spot defects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If micro lenses are added to improve light extraction efficiency, then luminance increases, but device complexity increases
Solution Approach 1:
The micro lenses are integrated into the existing overcoat layer structure, merging the light extraction function with the protective coating layer. This eliminates the need for separate light extraction components, thereby improving luminance without proportionally increasing device complexity.
Solution Approach 2:
The micro lenses introduce a three-dimensional refractive structure into the otherwise planar overcoat layer. By utilizing optical refraction through curved surfaces, the patent extracts light that would otherwise be trapped by total internal reflection, thereby enhancing luminance through geometric optimization rather than adding complex functional components.
2Loss of energy
If micro lenses are placed in all emission areas, then light extraction efficiency improves, but risk of electrical short circuits and bright spot defects increases
Solution Approach 1:
The patent applies micro lenses selectively in specific regions of the emission area rather than uniformly across all areas. By removing micro lenses from certain outermost regions where they would cause electrical short circuits or bright spot defects, the design optimizes light extraction efficiency in safe zones while maintaining electrical reliability in critical areas.
Solution Approach 2:
The emission area is segmented into regions where micro lenses are appropriate and regions where they should be removed. This segmentation allows the patent to optimize light extraction in inner emission areas while preventing electrical failures at the boundaries, thereby balancing energy efficiency with system reliability.
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
Enhances light extraction efficiency, improves luminance, and reduces power consumption by effectively redirecting internally reflected light, while preventing electrical short circuits and bright spot defects through strategic micro lens placement.
Implementation Method 1
if some light is not emitted to the outside due to total internal reflection at the interface between the components
Implementation Method 2
Incorporating micro lenses in the overcoat layer of OLED display devices, specifically arranged in the emission areas of sub-pixels with varying configurations to redirect and extract light
Data Source
AI summary
An organic light-emitting diode display device can include a display area, a non-display area outside the display area, a plurality of sub-pixels in the display area, each sub-pixel having an emission area and a non-emission area, and an overcoat layer including a plurality of micro lenses in the emission area of each sub-pixel. For an outermost sub-pixel among the plurality of sub-pixels, the overcoat layer has a first flat portion where some micro lenses are removed from the emission area.