Touch Control Panel Concave-Convex Structures for Foldable Displays
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Solution Overview
Problem
Flexible touch control display panels face issues such as bubbles, cracking, and layer separation when folded due to stress between film layers, which is exacerbated by increasing the thickness of the optically clear adhesive layer to enhance adhesion, thereby compromising the panel's resilience.
Innovation Solution
Incorporating concave-convex fine structures on the surfaces of the touch control panel and flexible substrate, bonded with an optically clear adhesive layer, which increases adhesion and reduces stress, preventing bubbles and layer separation while maintaining resilience.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the thickness of the optically clear adhesive layer is increased to enhance adhesion between film layers, then the adhesion is improved, but the overall resilience property of the flexible touch control display panel deteriorates
Solution Approach 1:
The invention introduces concave-convex fine structures at specific locations on the film layers (particularly on the TSP and adjacent films) to create localized adhesion enhancement zones. This allows the adhesive function to be concentrated where needed without requiring a uniformly thick OCA layer throughout, thereby maintaining the panel's overall flexibility and resilience while achieving sufficient adhesion at critical interfaces.
Solution Approach 2:
Instead of increasing adhesion by adding thickness in the vertical dimension (thicker OCA layer), the invention transitions to a surface topology approach by creating concave-convex fine structures. This dimensional shift from volumetric thickening to surface feature engineering enables adhesion enhancement without compromising the panel's bending resilience.
2Stress or pressure
If the thickness of the optically clear adhesive layer is increased to reduce stress on the cover film, then the stress received by the cover film is reduced, but the overall resilience property deteriorates
Solution Approach 1:
The concave-convex fine structures create localized stress distribution zones that reduce peak stresses on the cover film during bending. By concentrating adhesion and stress management functions at specific surface locations rather than distributing them uniformly through increased OCA thickness, the panel maintains both stress reduction and resilience.
Solution Approach 2:
The invention changes the physical parameters of the adhesive interface by introducing surface topography (concave-convex structures with specific dimensions: convex portions with diameter 1-10 μm, depth 0.5-5 μm). This parameter change enables effective stress management without requiring increased adhesive layer thickness, thereby preserving panel resilience.
3Device complexity
If conventional flat film layers are used in the flexible display panel, then the structure is simple, but bubbles, cracking, and layer separation occur when folded due to stress between film layers
Solution Approach 1:
Rather than making the entire film structure complex, the invention applies concave-convex fine structures only at specific locations on the film layers where adhesion is critical. This localized approach improves bending resistance and prevents defects like bubbles and layer separation while maintaining relative structural simplicity elsewhere in the panel.
Solution Approach 2:
The invention addresses reliability issues by transitioning from flat two-dimensional film interfaces to three-dimensional concave-convex surfaces. This dimensional enhancement creates mechanical interlocking and increased surface area for adhesion, preventing bubbles, cracking, and layer separation during folding without significantly complicating the overall device structure.
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 concave-convex fine structures enhance the bending resistance of foldable display modules by improving adhesion and reducing stress, effectively preventing issues like bubbles and cracking, while maintaining the overall resilience of the panel.
Implementation Method 1
at least one surface of the touch control panel has a plurality of concave-convex fine structures... the concave-convex fine structures enhance the bending resistance of foldable display modules by improving adhesion
Implementation Method 2
the display panel and one surface of the touch control panel having the concave-convex fine structures are bonded by an optically clear adhesive layer
Data Source
AI summary
There is provided a display apparatus and a production method thereof. The display apparatus has a touch control panel and a display panel, wherein at least one surface of the touch control panel has a plurality of concave-convex fine structures, and wherein the touch control panel is on a light-emitting side of the display panel. The touch control panel may have: a flexible substrate having a plurality of concave-convex fine structures on at least one surface; and a touch control electrode having at least one part formed on one or more concave-convex fine structures of the flexible substrate.