OLED Insulating Layer Refractive Index Total Reflection
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Solution Overview
Problem
OLED display devices suffer from significant light loss due to total reflection at interfaces between different media, resulting in low light output efficiency, with internal quantum efficiency being limited to 20% even with 100% internal quantum efficiency.
Innovation Solution
Incorporating an insulating layer with a refractive index greater than the pixel-defined layer between the light-emitting layer and the pixel-defined layer, which is curved or has microplanes to achieve total reflection and improve light output efficiency, and manufacturing this structure using materials like Ti2O3, TiO2, or ZnSe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If light beam is transmitted from light-emitting layer through pixel-defined layer to outside, then display function is achieved, but total reflection at interface between pixel-defined layer and air causes significant light loss
Solution Approach 1:
An insulating layer with higher refractive index (such as Ti2O3, TiO2, or ZnSe) is introduced between the light-emitting layer and pixel-defined layer. This intermediary layer creates favorable refractive index conditions that enable total reflection of light beams at the interface between the insulating layer and pixel-defined layer, thereby improving light output efficiency while maintaining display function.
Solution Approach 2:
The patent changes the refractive index parameter by introducing an insulating layer with refractive index greater than that of the pixel-defined layer. This parameter change transforms the optical characteristics at the interface, enabling total reflection and significantly reducing light loss in the display device.
2Illumination intensity
If insulating layer with higher refractive index is added to achieve total reflection, then light output efficiency is improved, but device structure becomes more complex
Solution Approach 1:
The insulating layer serves multiple functions simultaneously: it provides electrical insulation between the light-emitting layer and pixel-defined layer, and it creates the refractive index difference necessary for total reflection. This multi-functionality improves light output efficiency without requiring additional dedicated components, thereby limiting the increase in device complexity.
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 solution significantly enhances light output efficiency by totally reflecting light beams at the interface between the insulating and pixel-defined layers, allowing more light to be transmitted to the cathode layer for display, thereby improving external quantum efficiency.
Implementation Method 1
total reflection will occur at an interface between the pixel-defined layer 103 and air due to a significant difference between refractive indices of the pixel-defined layer 103 and air
Implementation Method 2
The light beam is refracted when it passes from one medium into another medium
Data Source
AI summary
The present disclosure provides an OLED display device and its manufacturing method. The OLED display device includes an anode layer, a cathode layer, and a pixel-defined layer and a light-emitting layer both arranged between the anode layer and the cathode layer. The pixel-defined layer is provided with an opening, and the light-emitting layer is arranged in the opening. An insulating layer having a refractive index greater than that of the pixel-defined layer is arranged between the light-emitting layer and the pixel-defined layer.