Flexible Substrate With Elastic Modulus Gradient for Display Reliability
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Solution Overview
Problem
Traditional flexible display screens experience electrical failure and poor performance when bent due to excessive strain on the bending zone, leading to fracture and operational issues.
Innovation Solution
A flexible substrate with distinct bending and non-bending zones, where the elastic modulus of the bending zone is lower than the non-bending zone, allowing the neutral layer to shift and reduce strain on the display unit, thereby improving the screen's operational reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the flexible substrate has uniform elastic modulus throughout, then the structure is simple and easy to manufacture, but the strain on the display unit during bending is excessive causing fracture and electrical failure
Solution Approach 1:
The flexible substrate is designed with different elastic moduli in different regions: the bending zone has a lower elastic modulus (first elastic modulus) while the non-bending zone has a higher elastic modulus (second elastic modulus). This local differentiation allows the bending zone to flex more easily during screen bending, reducing strain on the display unit, while the non-bending zone maintains structural stability. The substrate thus has non-uniform material properties optimized for different functional requirements.
2Reliability
If the elastic modulus of the bending zone is reduced to move the neutral layer away from the flexible substrate, then the strain on the display unit is reduced, but the manufacturing precision and material selection become more challenging
Solution Approach 1:
The patent changes the elastic modulus parameter of the flexible substrate material in different regions. The bending zone uses material with a first elastic modulus specifically selected to be lower than the second elastic modulus of the non-bending zone. This parameter change enables the neutral layer to shift position during bending, moving it away from the flexible substrate surface and into the substrate thickness, thereby reducing the strain experienced by the display unit bonded to the substrate surface.
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 flexible substrate design effectively reduces strain on the display unit during bending, enhancing the mechanical reliability and probability of correct operation by distributing stress more evenly, thus preventing electrical failures.
Implementation Method 1
An elastic modulus of the first bending zone of the flexible substrate is less than an elastic modulus of the non-bending zone. When the flexible display screen is bent in the first bending zone, since the elastic modulus of the flexible substrate in the first bending zone is less than the elastic modulus in the non-bending zone, such that the neutral layer of the first bending zone can be moved toward the side away from the flexible substrate
Data Source
AI summary
The present disclosure relates to a flexible substrate and a flexible display screen. The flexible substrate includes a first bending zone and a non-bending zone. An elastic modulus of the flexible substrate in the first bending zone is smaller than the elastic modulus in the non-bending zone. When the flexible display screen is bent in the first bending zone, since the elastic modulus of the flexible substrate in the first bending zone is smaller than the elastic modulus in the non-bending zone, such that the neutral layer of the first bending zone moves toward a side away from the flexible substrate, thereby reducing the strain on the display unit located on the side of the first bending area, avoiding the breakage of the metal trace and improving the probability of correct operation of the screen.