Flexible Display Substrate Barrier Stack for Moisture and Stress Control
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Solution Overview
Problem
Conventional glass substrates for flexible displays are prone to breakage and lack flexibility, while plastic substrates have high moisture and oxygen penetration issues, making them unsuitable for high-temperature processes and durable, flexible display applications.
Innovation Solution
A substrate with a plastic substrate having a glass transition temperature between 350° C. to 500° C., combined with a multi-layer barrier layer composed of alternately stacked silicon oxide and silicon nitride layers, providing excellent oxygen and moisture blocking characteristics and suitable film stress for flexible display devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a conventional glass substrate is used for flexible displays, then the display can be thin and light, but the substrate is prone to breakage and lacks flexibility
Solution Approach 1:
The patent uses a composite structure consisting of a plastic substrate combined with a multi-layer barrier layer (alternating silicon oxide and silicon nitride layers). This composite material approach allows the substrate to maintain flexibility and light weight while the barrier layers provide the necessary protection against moisture and oxygen penetration, resolving the contradiction between using lightweight plastic and ensuring durability.
2Adaptability or versatility
If a plastic substrate is used for flexible displays, then the substrate has flexibility and can be bent, but the substrate has high moisture and oxygen penetration
Solution Approach 1:
The patent combines a flexible plastic substrate with a multi-layer barrier structure consisting of alternating silicon oxide and silicon nitride layers. The plastic substrate provides the necessary flexibility and adaptability, while the barrier layers collectively block moisture and oxygen penetration, thus resolving the contradiction between flexibility and protection against harmful factors.
Solution Approach 2:
The barrier layer structure employs a nested multi-layer configuration where silicon oxide and silicon nitride layers are alternately stacked. Each layer嵌套 within the overall barrier structure, with the silicon nitride layers providing tensile stress to compensate for compressive stress in silicon oxide layers, creating a nested protective system that maintains flexibility while blocking harmful factors.
3Adaptability or versatility
If a plastic substrate is used for flexible displays, then the substrate can be flexible, but it is not suitable for high temperature processes
Solution Approach 1:
The patent uses a composite structure where the plastic substrate is combined with a multi-layer barrier system. The barrier layers, particularly the silicon nitride layers, provide thermal stability and protect the plastic substrate during high-temperature manufacturing processes, enabling the flexible substrate to withstand temperatures that would otherwise degrade the plastic material.
4Object-affected harmful factors
If a multi-layer barrier layer with alternating silicon oxide and silicon nitride layers is used, then oxygen and moisture blocking characteristics are excellent, but the device complexity increases
Solution Approach 1:
The patent employs a nested multi-layer structure where silicon oxide and silicon nitride layers are alternately stacked in a repeating pattern. This nested configuration allows each layer to serve multiple functions: silicon oxide provides compressive stress and moisture barrier, while silicon nitride provides tensile stress compensation and oxygen barrier. The nested structure achieves excellent blocking characteristics while maintaining a relatively compact and manufacturable design.
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 enables the creation of a thin, flexible display substrate that is resistant to moisture and oxygen penetration, maintaining stability during high-temperature processes and ensuring the longevity of electronic devices like thin film transistors without causing stress-related defects.
Implementation Method 1
a barrier layer disposed on the plastic substrate, having a multi-layer structure, wherein at least one silicon oxide layer and at least one silicon nitride layer are alternately stacked on each other, and having a film stress from about −200 MPa to about 200 MPa due to the at least one silicon oxide layer and the at least one silicon nitride layer
Implementation Method 2
having a film stress from about −200 MPa to about 200 MPa due to the at least one silicon oxide layer and the at least one silicon nitride layer
Data Source
AI summary
A substrate for a flexible display is disclosed. The substrate has a film stress range that does not affect an electronic device such as a thin film transistor, and includes a barrier layer having excellent oxygen and moisture blocking characteristics, and a method of manufacturing the substrate. The substrate includes: a plastic substrate having a glass transition temperature from about 350° C. to about 500° C.; and a barrier layer disposed on the plastic substrate, having a multi-layer structure, wherein at least one silicon oxide layer and at least one silicon nitride layer are alternately stacked on each other, and having a film stress from about −200 MPa to about 200 MPa due to the at least one silicon oxide layer and the at least one silicon nitride layer.