Composite Bendable Elements for Crease-Resistant Foldable Displays
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Solution Overview
Problem
Existing bendable and foldable electronic devices face challenges in achieving a combination of sufficient bendability and mechanical resistance, particularly in maintaining shape stability and minimizing creases and delamination due to deformation from folding/unfolding processes.
Innovation Solution
A bendable element with specific thickness, width, and length, capable of bending to a radius of 5.0 mm without failure, featuring reduced persistent deformation of up to 3.0 mm and deformation recovery time of less than 10 hours, composed of a glass layer and polymer layers with creep resistance, and optionally non-polymer layers to enhance mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the bendable element is made thinner to achieve smaller bending radius, then bendability is improved, but mechanical strength and resistance to impact deteriorate
Solution Approach 1:
The patent employs a composite structure consisting of multiple layers including glass layers, polymer layers, and adhesive layers. This composite material approach allows the bendable element to achieve both high bendability (bending radius of 5.0 mm) and mechanical strength by combining materials with complementary properties - the glass provides rigidity and strength while the polymer layers provide flexibility and creep resistance.
2Adaptability or versatility
If the element is bent frequently to enable folding functionality, then adaptability is improved, but persistent deformation and creases increase
Solution Approach 1:
The patent optimizes specific material parameters including the thickness of each layer (glass layer: 0.1-0.5 mm, polymer layer: 0.01-0.1 mm), the creep resistance values (G' > 100 MPa, G'' < 10 MPa), and the total thickness (0.1-0.5 mm) to achieve a balance between folding capability and shape stability, minimizing persistent deformation after repeated bending cycles.
Solution Approach 2:
The multi-layer composite structure with specifically selected materials provides resistance to persistent deformation and crease formation. The polymer layers with high creep resistance and the adhesive layers work together to maintain shape stability while allowing frequent folding operations.
3Ease of operation
If the element is made more flexible to reduce bending radius, then ease of operation is improved, but resistance to impact and mechanical failure deteriorates
Solution Approach 1:
The composite structure combines flexible polymer layers with more rigid glass layers and adhesive layers in specific thickness ratios. This allows the element to be bent to a radius of 5.0 mm while maintaining resistance to impact and mechanical failure through the synergistic properties of the composite materials.
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 solution ensures minimal crease and delamination, rapid deformation recovery, and mechanical stability, allowing the element to maintain its original shape quickly after stress release, suitable for use in foldable displays and electronic devices.
Implementation Method 1
the polymer layers have a creep resistance of at least 0.70
Implementation Method 2
the element has reduced persistent deformation characterized by a total persistent deformation a0 of not more than 3.0 mm and a deformation recovery time b1 of less than 10 hours after bending
Data Source
AI summary
The present disclosure relates to bendable elements. The bendable elements can be used in display covers for electronic devices such as smart phones. The elements have reduced delayed elastic deformation or creep when released from the influence of persistent mechanical stresses, e.g. unfolded from a folded position. The present disclosure also relates to covers for color filters, filter printed electronics, sensors for touch control panels, fingerprint sensors, mobile electronic devices, bendable/foldable displays that include the bendable elements as substrates, or other applications where a combination of high chemical stability, temperature stability, low gas permeability, flexibility, high strength, low thickness and premium cosmetic appearance is necessary. Besides consumer and industrial electronics the present disclosure could also be used for protection applications in industrial production or metrology.