Flexible Display Substrate Metal Interlayer Against PI Peeling
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Solution Overview
Problem
The reliability of flexible display devices is reduced due to the separation of the double-layer polyimide (PI) structure, where the binding force between the inorganic water vapor barrier layer and the upper layer PI is weaker than that between the inorganic and lower layer PI, leading to peeling issues under high temperature and humidity conditions.
Innovation Solution
Incorporating a metal layer between the inorganic barrier layer and the second organic layer, using materials like aluminum, silver, nickel, magnesium, or molybdenum, to enhance the bonding force and prevent separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a double-layer polyimide structure with an inorganic barrier layer is used, then water vapor barrier function is provided, but bonding force between the inorganic barrier layer and the upper layer PI is weak leading to peeling
Solution Approach 1:
A metal layer is introduced as an intermediary between the inorganic barrier layer and the second organic layer. The metal layer serves as a mediator that enhances bonding force between these two layers, preventing peeling and separation under high temperature and humidity conditions while maintaining the water vapor barrier function of the inorganic layer.
Solution Approach 2:
The flexible substrate employs a composite multi-layer structure consisting of first organic layer, inorganic barrier layer, metal layer, and second organic layer. This composite structure combines the water vapor barrier properties of the inorganic layer with the bonding enhancement properties of the metal layer and the flexibility of the organic layers, resolving the contradiction between barrier function and bonding strength.
2Adaptability or versatility
If double-layer polyimide structure is used to provide flexibility, then bending capability is achieved, but bonding reliability deteriorates due to weak adhesion between layers
Solution Approach 1:
The metal layer acts as an intermediary that enhances interlayer bonding while maintaining flexibility. It provides strong adhesion between the inorganic barrier layer and the second organic layer, preventing delamination during bending operations while allowing the substrate to maintain its bending capability.
Solution Approach 2:
The metal layer performs multiple functions simultaneously: it enhances bonding force between layers, provides electrical conductivity pathways, and maintains mechanical flexibility. This multi-functionality allows the substrate to achieve both bending capability and bonding reliability without compromise.
Data Source
AI summary
A flexible substrate, including: a first organic layer, an inorganic barrier layer, a metal layer and a second organic layer which are stacked in sequence, and the metal layer is for improving binding force between the inorganic barrier layer and the second organic layer. According to embodiments of the present disclosure, the metal layer is provided between the inorganic barrier layer and the second organic layer, so as to improve bonding force between the inorganic barrier layer and the second organic layer, prevent the second organic layer from peeling off from the inorganic barrier layer, and further improve reliability of a flexible display device.