OLED Refraction Inducing Layer for Light Extraction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Organic light emitting diode (OLED) display devices suffer from low light extraction efficiency due to total reflection and absorption by anode electrodes and substrates, resulting in significant light being trapped inside the device, and the use of micro lens arrays or low index grids often leads to non-emission areas and ghosting phenomena.
Innovation Solution
The OLED display device incorporates a refractive index structure with a first insulating layer, a refraction inducing layer, and a second insulating layer, along with electrodes, featuring convex and concave parts to optimize light refraction and reduce total reflection, thereby enhancing light extraction efficiency and minimizing non-emission areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a micro lens array is formed on the overcoat layer to improve light extraction efficiency, then light extraction efficiency is improved, but a large quantity of light is still locked in the diode and the quantity of light extracted to the outside is small
Solution Approach 1:
The patent divides the light extraction function into multiple components: the micro lens array segments the light paths, while the refraction inducing layer with convex and concave parts further segments and redirects light. This multi-level segmentation allows light to be extracted more effectively through different mechanisms working in combination.
Solution Approach 2:
The patent introduces a new dimensional approach by adding the refraction inducing layer with three-dimensional convex and concave structures between the micro lens array and the organic light emitting layer. This additional dimensional element creates new light extraction pathways that were not available with the micro lens array alone.
2Loss of energy
If a plurality of low index grid patterns are disposed on the anode electrode to improve light extraction efficiency, then light extraction efficiency is improved, but non-emission areas are generated and blurring and ghost phenomena are observed
Solution Approach 1:
The patent extracts the refraction function from the anode electrode by placing the refraction inducing layer with convex and concave parts in a different location within the device structure. This separates the light extraction function from the electrode, eliminating the creation of non-emission areas while maintaining improved light extraction efficiency.
Solution Approach 2:
The refraction inducing layer acts as an intermediary between the micro lens array and the organic light emitting layer, providing a mediation mechanism for light extraction that avoids the direct pattern formation on the anode electrode. This intermediary layer enables light extraction improvement without creating the harmful non-emission areas and optical defects.
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 increases the number of times light is incident on micro lenses, improves light extraction efficiency, and extends the lifespan of the OLED by reducing trapped light, while eliminating the need for low reflective index patterns that cause non-emission areas.
Implementation Method 1
a refraction inducing layer disposed on the first insulating layer and having a second refractive index... When light is incident on the second insulating layer at an angle larger than a critical angle for total reflection, the light may be incident onto the second insulating layer more than once via the refraction inducing layer
Implementation Method 2
the second insulating layer, the first electrode, the organic light emitting layer, and the second electrode include a plurality of convex parts and a plurality of concave parts
Data Source
AI summary
An organic light emitting diode display device is provided. The organic light emitting diode display device includes a first insulating layer disposed on a substrate and having a first refractive index, a refraction inducing layer disposed on the first insulating layer having a second refractive index, a second insulating layer disposed on the refraction inducing layer and having a third refractive index, a first electrode disposed on the second insulating layer and having a fourth refractive index, and an organic light emitting layer and a second electrode disposed on the first electrode. The second insulating layer, the first electrode, the organic light emitting layer, and the second electrode include a plurality of convex parts and a plurality of concave parts.