Foldable Cover Structure With Blunted Glass Edges for Small Bend Radius
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Solution Overview
Problem
Conventional foldable displays and protective covers face challenges in achieving small minimum bend radii while maintaining good impact and puncture resistance, with glass-based substrates either having poor resistance or large bend radii, and plastic substrates lacking durability.
Innovation Solution
The foldable apparatus incorporates glass-based, ceramic-based, and polymer-based portions with compressive stress regions and blunted edges, along with a polymer-based portion to minimize stress concentrations and provide enhanced folding performance, impact resistance, and puncture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If glass-based substrates are used to provide good impact and puncture resistance, then durability is improved, but minimum bend radius increases (making folding difficult)
Solution Approach 1:
The glass-based substrate is divided into multiple discrete beads or particles rather than a continuous sheet. This segmentation allows the substrate to flex and conform to smaller bend radii while maintaining the impact and puncture resistance of glass material, as the individual beads can rearrange and compress during folding.
Solution Approach 2:
The patent uses a flexible polymer encapsulant material that surrounds and binds the glass beads together. This flexible matrix allows the rigid glass beads to be arranged in a configuration that can bend to small radii while the glass beads themselves provide the necessary durability and resistance to impact and puncture forces.
2Shape
If plastic substrates are used to achieve small minimum bend radii, then folding performance is improved, but impact and puncture resistance deteriorates
Solution Approach 1:
The patent creates a composite structure combining rigid glass beads with a flexible polymer matrix. The glass beads provide impact and puncture resistance, while the polymer encapsulant provides flexibility and enables small bend radii. This composite approach allows both requirements to be satisfied simultaneously by leveraging the complementary properties of the two materials.
3Shape
If ultra-thin glass-based sheets are used to enable small minimum bend radii, then folding performance is improved, but impact and puncture resistance deteriorates
Solution Approach 1:
Instead of using an ultra-thin continuous glass sheet which lacks strength, the patent segments the glass into discrete beads. This segmentation allows the use of glass material (which has excellent impact and puncture resistance) while the discrete bead structure enables flexibility and small bend radii that would be impossible with a thin continuous sheet.
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 enables foldable apparatus with effective bend radii of 1-20 mm, reduced stress concentrations, and improved durability, minimizing optical distortions and adhesion-based failures, while maintaining consistent properties across the interface.
Implementation Method 1
Providing a polymer-based portion contacting a surface area of the first portion and/or the second portion can reduce folding-induced stresses on a coating and/or substrate, for example, by shifting a neutral axis of the coating and/or substrate closer to the polymer-based portion than a mid-plane of the coating and/or substrate
Implementation Method 2
The first portion and/or the second portion can comprise glass-based portions and/or ceramic-based portions comprising one or more compressive stress regions, which can further provide increased impact resistance and/or increased puncture resistance
Implementation Method 3
A first edge surface of the first portion and a second edge surface of the second portion can comprise a blunted edge surface, which can minimize stress concentrations, for example, at an interface between the first portion and/or the second portion and the polymer-based portion
Implementation Method 4
the polymer-based portion and/or an adhesive layer (e.g., first, second, third) can comprise a refractive index that can substantially match (e.g., a magnitude of a difference of about 0.1 or less) a refractive index of the first portion and/or the second portion, which can minimize optical distortions
Data Source
AI summary
Foldable apparatus can comprise a first portion comprising a first edge surface defined between a first surface area and a second surface area opposite the first surface area. Foldable apparatus can comprise a second portion comprising a second edge surface defined between a third surface area and a fourth surface area opposite the third surface area. A polymer-based portion can be positioned between the first blunted edge surface and the second blunted edge surface. In some embodiments, the polymer-based portion can comprise a polymer thickness of about 50 micrometers or less measured from the second surface area and/or the first surface area. In some embodiments, the first edge surface and/or the second edge surface can comprise a blunted edge surface. In some embodiments, a coating can be disposed over the first portion, the second portion and the polymer-based portion.