Low Refractive Thin Film for OLED Light Extraction
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Solution Overview
Problem
Active matrix type organic electro luminescence display panels face limitations in life span and light emission efficiency due to the use of high refractive insulating layers, which reduce light transmission and cause non-uniform brightness.
Innovation Solution
The implementation of a low refractive thin film, such as silica aerogel or silica gel, on the substrate to form an organic electro luminescence diode, allowing light to be emitted directly through the anode, thereby improving light emission efficiency and brightness uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If high refractive insulating layers are used in the display panel, then electrical insulation and device structure are improved, but light transmission and brightness uniformity deteriorate
Solution Approach 1:
The patent applies different refractive index materials to different regions: high refractive index materials (insulating layers) in non-light-emitting regions and low refractive index material (aerogel) in the light emission region. This local differentiation allows electrical insulation where needed while optimizing light transmission where light is emitted, resolving the contradiction between insulation reliability and brightness uniformity.
Solution Approach 2:
The aerogel layer acts as an intermediary between the substrate and the organic EL diode in the light emission region. This intermediary material with low refractive index (1.05-1.20) reduces optical refraction and improves light extraction efficiency, thereby enhancing brightness uniformity without compromising the electrical insulation provided by other insulating layers in the device structure.
2Device complexity
If conventional insulating layers are used, then device structure is simplified, but light emission efficiency is reduced
Solution Approach 1:
The patent changes the refractive index parameter of the thin film in the light emission region by using aerogel material with refractive index of 1.05-1.20, which is significantly lower than conventional insulating layers. This parameter change reduces optical refraction at interfaces and improves light extraction efficiency from the organic EL diode, thereby reducing energy loss without substantially complicating the device structure.
3Ease of manufacture
If standard thin films are used, then fabrication process is straightforward, but light transmission and brightness are limited
Solution Approach 1:
The patent employs a composite structure where aerogel material is integrated into the existing thin film stack in the light emission region. The aerogel can be deposited as a thin layer (50-500 nm) using conventional techniques, maintaining fabrication simplicity while the unique optical properties of aerogel (low refractive index, high porosity) significantly enhance light transmission and brightness.
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 approach enhances light emission efficiency by approximately 2.5 times and improves brightness and uniformity by allowing more light to be transmitted through the substrate, reducing refraction and dispersion.
Implementation Method 1
a low refractive thin film, such as silica aerogel or silica gel, on the substrate to form an organic electro luminescence diode, allowing light to be emitted directly through the anode, thereby improving light emission efficiency and brightness uniformity
Implementation Method 2
In the organic EL diode OLED, if an organic luminous material is supplied with a forward current, holes and electrons are moved to a light emission layer formed between a hole transport layer and an electron transport layer
Data Source
AI summary
An active matrix organic electro luminescence display panel device includes a substrate, at least one low refractive thin film formed on the substrate, and an organic electro luminescence diode formed on the low refractive thin film to selectively emit light. Also, a method of fabricating an active matrix organic electro luminescence display panel device includes the steps of forming at least one low refractive thin film on a substrate, and forming an organic electro luminescence diode on the low refractive thin film to selectively emit light.