Elastic Support Columns in Foldable Touch Displays
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Solution Overview
Problem
Current foldable touch control display devices face issues with optically clear adhesive (OCA) deformation due to repeated folding, which is difficult to recover, leading to stress concentration and crease formation, and the existing solutions struggle to maintain effective viscosity and gap filling without causing bubble generation.
Innovation Solution
The implementation of elastic support columns made of organic transparent materials, uniformly distributed on the foldable region, with an adhesive filled around them, where the height of each column varies based on stress magnitude, ensuring optimal folding and adhesion to maintain the display's appearance before and after folding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the thickness of OCA is reduced to improve crease recovery, then the crease recovery is improved, but the OCA cannot effectively fill gap differences between layers and cannot maintain good viscosity
Solution Approach 1:
The patent applies local quality by creating varying thickness regions within the OCA layer. The OCA is applied with different thicknesses in different areas: thinner in regions requiring flexibility and crease recovery, and thicker in regions requiring gap filling and structural stability. This spatial variation in thickness allows the single OCA layer to simultaneously satisfy both the crease recovery requirement and the gap filling/viscosity requirement.
2Shape
If the thickness of OCA is reduced to improve crease recovery, then the crease recovery is improved, but bubble generation risk increases
Solution Approach 1:
The patent uses local quality to address bubble generation by strategically varying OCA thickness. In areas prone to bubble formation during folding, the OCA is applied with optimized thickness that balances flexibility and air entrapment prevention. This localized thickness control reduces bubble generation risk while preserving crease recovery capability.
3Reliability
If OCA thickness is increased to improve gap filling, then the gap filling is improved, but the recovery time increases to at least a few hours
Solution Approach 1:
The patent resolves this contradiction by applying OCA with locally optimized thickness. In regions where gap filling is critical, the OCA is applied thicker to ensure proper adhesion and gap filling. In regions where rapid recovery is needed, the OCA is applied thinner to enable faster elastic recovery. This spatial differentiation allows the system to achieve both effective gap filling and reduced recovery time.
4Reliability
If OCA thickness is increased to maintain viscosity, then the viscosity is maintained, but the crease formation and stress concentration worsen
Solution Approach 1:
The patent applies local quality by varying OCA thickness to balance viscosity maintenance and crease prevention. In areas requiring strong adhesion and viscosity, the OCA is applied thicker. In areas prone to crease formation and stress concentration, the OCA is applied thinner to reduce the deforming force while maintaining sufficient viscosity for adhesion through the optimized thickness distribution.
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
This solution prevents non-recoverable adhesive deformation and ensures a flexible foldable touch control display by providing support and firm adhesion, reducing crease formation and maintaining the display's integrity during repeated folding.
Implementation Method 1
the supporting pillar structures comprises elastic support columns distributed on the foldable region
Implementation Method 2
an adhesive filled around the elastic support columns
Data Source
AI summary
The present disclosure provides a display device, including elastic support columns formed on a foldable region of a touch control sensing layer and an adhesive filled around the elastic support columns; the height of the elastic support columns varies with the magnitude of the stress, and the thickness of the adhesive is controlled by adjusting the height and the density of the elastic support columns to ensure the best folding results. It is possible to maintain the product appearance without apparent changes before and after folding to avoid the adhesive deformation which is not recoverable due to the much thick adhesive and a repeated folding, and realize a flexible foldable touch control display.