Transparent Moisture Absorption Layer for OLED Sealing
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Solution Overview
Problem
Existing organic electroluminescent devices face challenges with moisture permeation, leading to device deterioration, high manufacturing costs, and limited light extraction due to complex sealing processes and opaque desiccants, which result in a short lifespan and reduced light transmission.
Innovation Solution
An organic electroluminescent device with a transparent moisture absorption layer formed using a sealing substrate and a sealing layer composed of a cohesion layer, a transparent polymer layer, and a transparent nanoporous membrane, applied via an attaching method to prevent contamination and outgasing, ensuring a firm sealed structure and effective light extraction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a liquid phase type transparent moisture absorption material is filled in a glass cap and heat treated to form a coating layer, then moisture absorption function is achieved, but side portions of the sealing layer are contaminated and outgasing occurs during heat treating, weakening bonding force between sealant and sealing substrate
Solution Approach 1:
The patent applies a transparent moisture absorption material in sol state (a precursor state) before heat treatment, rather than applying liquid phase material and then heat treating. This preliminary application in sol state prevents contamination of side portions during the process, as the sol state material can be precisely deposited and then converted to the functional coating through controlled heat treatment in a furnace without causing outgasing issues.
Solution Approach 2:
The patent changes the physical state parameter of the moisture absorption material from liquid phase to sol state. This parameter change allows the material to be applied in a controlled manner that prevents side portion contamination, and then transformed into the functional transparent coating through heat treatment, resolving the contradiction between achieving moisture absorption function and preventing manufacturing defects.
2Reliability
If a liquid phase type transparent moisture absorption material is heat treated to form a coating layer, then moisture absorption function is achieved, but outgasing occurs during heat treating, weakening bonding force between sealant and sealing substrate
Solution Approach 1:
The patent applies the moisture absorption material in sol state before heat treatment, which allows for precise deposition and controlled transformation. This preliminary action in sol state prevents outgasing during heat treatment that would otherwise weaken the bonding force between sealant and sealing substrate, while still achieving the desired moisture absorption function through the subsequent controlled firing process.
Solution Approach 2:
By changing the application state from liquid phase to sol state, the patent enables a controlled parameter transformation during heat treatment that avoids outgasing. This parameter change ensures that the bonding force between sealant and sealing substrate is maintained while still achieving the moisture absorption function through the sol-to-coating transformation.
3Strength
If conventional sealing methods with metallic can or glass cap are used, then structural firmness is achieved, but total thickness of substrates increases and substrate cannot be used for front light emission
Solution Approach 1:
The patent replaces conventional thick metallic cans or glass caps with a thin film transparent sealing layer formed by applying and heat treating a transparent moisture absorption material in sol state. This thin film structure maintains the necessary sealing function and structural firmness while being transparent, enabling front light emission. The sol state application method ensures precise deposition of this thin protective layer.
4Illumination intensity
If etched glass is used for sealing, then transparency is achieved, but structural weakness makes it easily impaired by external impact
Solution Approach 1:
The patent creates a composite structure by forming a transparent moisture absorption coating layer on the sealing substrate. This composite structure combines the transparency of the base glass with the enhanced protective properties of the fired sol-derived coating layer, resulting in a sealing structure that maintains transparency while gaining improved resistance to external impact.
Solution Approach 2:
The patent applies a thin film transparent moisture absorption coating on the sealing substrate through sol state deposition and heat treatment. This thin film layer provides additional protective functionality that enhances the mechanical strength and impact resistance of the transparent sealing structure without compromising its transparency or light emission capabilities.
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 provides a longer lifespan and improved light extraction efficiency through the transparent moisture absorption layer, maintaining high light transmittance and luminance stability over time, while reducing manufacturing costs and enhancing the device's durability against external impacts.
Implementation Method 1
a transparent moisture absorption layer formed using an attaching method
Implementation Method 2
effective light extraction through a sealing substrate
Data Source
AI summary
An organic electroluminescent device and a method of preparing the same are provided. The organic electroluminescent device includes a sealing layer which is formed on a sealing substrate, and which includes a cohesion layer, a transparent polymer layer, and a transparent moisture absorption layer. Since the transparent moisture absorption layer of the organic electroluminescent device is provided to a sealing substrate using an attaching method, the organic electroluminescent device has an improved life span property due to a firm sealed structure and better light extraction efficiency due to the transparent moisture absorption layer below the sealing substrate.