Flexible Display Insulating Layer Cutouts
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Solution Overview
Problem
Flexible display devices face issues with cracking in the insulating layer and short circuits between wires due to bending, which can lead to display defects.
Innovation Solution
A flexible display device design featuring a flexible substrate with a bending area that includes an insulating layer with cutouts having inclined lateral walls, where the width of the walls is equal to or greater than the depth of the cutout, and wires are formed along the surface shape of the insulating layer, preventing cracking and short circuits through isotropic etching using an etching paste.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the insulating layer is made continuous and complete to ensure electrical insulation, then insulation performance is improved, but cracking occurs during bending due to stress concentration
Solution Approach 1:
The insulating layer is segmented by forming cutouts that extend from the first surface toward the second surface. These cutouts divide the continuous insulating layer into multiple segments, allowing each segment to independently accommodate bending stress without causing cracks that would compromise the entire insulation system. The cutouts create a flexible structure that maintains electrical insulation while enabling deformation.
Solution Approach 2:
The insulating layer is designed with non-uniform structure: regions with cutouts are provided in areas subject to bending stress, while other regions maintain continuous insulation. This local differentiation allows the structure to have both flexibility where needed and continuous insulation where electrical isolation is critical, resolving the contradiction between insulation integrity and bend resistance.
2Ease of manufacture
If wires are formed in straight lines to simplify manufacturing, then manufacturing ease is improved, but short circuits occur during bending due to wire deformation
Solution Approach 1:
The wire configuration is changed from static straight lines to dynamic curved paths that follow the surface topology of the insulating layer. The wires are formed to extend along the first surface, into the cutouts, and along the second surface, creating a flexible layout that can accommodate bending deformation without causing short circuits between adjacent wires.
3Manufacturing precision
If cutouts with vertical lateral walls are formed to simplify etching, then manufacturing precision is improved, but stress concentration occurs at the corners during bending
Solution Approach 1:
The cutouts are designed with asymmetric tapered geometry where the lateral walls are inclined rather than vertical. The inclination angle is configured to gradually reduce from the first surface toward the second surface, creating a shape that distributes bending stress more evenly along the cutout walls and avoids stress concentration at sharp corners, thereby improving crack resistance.
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
Effectively prevents cracking in the insulating layer and short circuits between wires during bending, enhancing the reliability and durability of the flexible display device.
Implementation Method 1
The at least one cutout may be formed by isotropic etching using an etching paste
Data Source
AI summary
A flexible display device includes: a flexible substrate including a bending area; an insulating layer formed on the flexible substrate and including at least one cutout formed to correspond to the bending area; and a plurality of wires formed along a surface shape of the insulating layer in the bending area. The at least one cutout may include an inclined lateral wall, and a width of the inclined lateral wall may be equal to or greater than a depth of the cutout.