Flexible OLED Composite Barrier Layer Stress Reduction
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Solution Overview
Problem
The manufacturing of flexible organic light emitting apparatuses faces challenges in maintaining barrier layer characteristics and reducing substrate stress, especially at high temperatures, which affects the stability and longevity of the devices due to differences in thermal expansion coefficients and the high water vapor transmission rates of conventional plastic substrates.
Innovation Solution
A composite barrier layer is implemented, comprising a first inorganic layer, a polyimide layer formed using a dry process such as thermal evaporation or PECVD, and a second inorganic layer, with specific monomers like perylenetetracarboxylic dianhydride and diaminododecane, and an encapsulation layer with a similar structure, to enhance stability and prevent moisture and oxygen penetration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional plastic substrate is used for flexible display devices, then flexibility is achieved, but the substrate exhibits high water vapor transmission rates and cannot maintain barrier layer characteristics at high temperatures
Solution Approach 1:
The patent employs a composite barrier layer structure consisting of alternating organic and inorganic layers. The organic layers (polyimide or acrylic resin) provide flexibility and stress buffering, while the inorganic layers (such as aluminum oxide, silicon oxide, or silicon nitride) provide low water vapor transmission rates and thermal stability. This composite structure maintains barrier characteristics at high temperatures while preserving substrate flexibility.
2Reliability
If a barrier layer is formed on a plastic substrate, then water vapor transmission is reduced, but substrate stress increases due to differences in thermal expansion coefficients
Solution Approach 1:
The patent controls the thickness parameters of individual layers within specific ranges (organic layer: 1-100 nm, inorganic layer: 1-50 nm) to optimize the balance between barrier performance and stress management. By adjusting these dimensional parameters, the composite structure achieves low water vapor transmission while minimizing substrate stress through proper layer thickness distribution.
Solution Approach 2:
The multi-layer composite structure with alternating organic and inorganic materials provides differential thermal expansion buffering. The organic layers have higher thermal expansion coefficients that match plastic substrates better, while inorganic layers provide barrier function, creating a gradient structure that reduces overall substrate stress.
3Manufacturing precision
If a dry process is used to form the polyimide layer, then manufacturing precision and thickness control are improved, but process complexity increases
Solution Approach 1:
The patent replaces conventional wet chemical deposition processes with dry deposition techniques such as chemical vapor deposition (CVD) or atomic layer deposition (ALD). These dry processes enable precise thickness control at the nanometer scale through vapor-phase reactions, eliminating the need for liquid chemicals and post-processing drying steps, thereby improving manufacturing precision while streamlining the overall process.
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 solution maintains barrier layer characteristics and reduces substrate stress, improving the manufacturing stability of organic light emitting apparatuses by using a dry process for polyimide formation, allowing for precise thickness adjustment and high step coverage, thus extending the device's lifetime and enabling mass production.
Implementation Method 1
depositing a monomer via a technique selected from a group consisting of a thermal evaporation technique, a plasma enhanced chemical vapor deposition (PECVD) technique and an atomic layer deposition (ALD) technique
Implementation Method 2
depositing a monomer via a technique selected from a group consisting of a thermal evaporation technique, a plasma enhanced chemical vapor deposition (PECVD) technique and an atomic layer deposition (ALD) technique
Implementation Method 3
depositing a monomer via a technique selected from a group consisting of a thermal evaporation technique, a plasma enhanced chemical vapor deposition (PECVD) technique and an atomic layer deposition (ALD) technique
Implementation Method 4
heating the monomer
Data Source
AI summary
An organic light emitting apparatus and a method of manufacturing the organic light emitting apparatus. According to the organic light emitting apparatus and the method of manufacturing the organic light emitting apparatus, the characteristics of a barrier layer are maintained and a stress of a substrate is reduced, even at a high temperature, thereby increasing the manufacturing stability of the organic light emitting apparatus.