Chemically Strengthened Foldable Ribbon for Small Bend Radius
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Solution Overview
Problem
Conventional foldable displays and protective covers suffer from poor impact and/or puncture resistance, particularly in achieving small minimum bend radii, and/or puncture resistance, particularly in achieving small minimum bend radii, and/or puncture resistance, particularly in achieving small minimum bend radii, and/or puncture resistance, particularly in achieving small minimum bend radii, and/or puncture resistance, particularly in achieving small minimum bend radii, and/or puncture resistance, particularly in achieving small minimum bend radii, and/or puncture resistance, particularly in achieving good impact and/or puncture resistance, particularly in achieving small minimum bend radii, and/or puncture resistance, particularly in achieving small minimum bend radii, and/or puncture resistance, particularly in achieving large maximum bend radii, and/or puncture resistance, especially in developing foldable apparatuses with low minimum bend radii and good impact and puncture resistance.
Innovation Solution
The foldable apparatus and ribbons comprise a foldable substrate with a central portion attaching a first portion to a second portion, featuring a central tensile stress region between first and second compressive stress regions, providing a central maximum tensile stress greater than the first and second maximum tensile stresses, and a central thickness less than the substrate thickness, enabling small minimum bend radii while maintaining good impact and puncture resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If plastic displays and covers are made with small minimum bend radii, then foldability is improved, but impact and puncture resistance deteriorates
Solution Approach 1:
The patent applies chemical strengthening to modify the physical parameters of the glass substrate, creating compressive stress regions that fundamentally change the material's mechanical properties. This allows the glass to achieve both small bend radii and high impact resistance by altering its internal stress state rather than changing its physical dimensions
Solution Approach 2:
The patent creates a composite stress structure within the glass substrate by forming multiple compressive stress regions through chemical strengthening. This composite arrangement of stress zones (first compressive region, second compressive region, and central tensile region) provides both flexibility and strength simultaneously
2Shape
If ultra-thin glass-based sheets are used to achieve small minimum bend radii, then foldability is improved, but impact and puncture resistance deteriorates
Solution Approach 1:
The patent uses chemical strengthening to change the stress parameters of the ultra-thin glass substrate, creating compressive stress regions that compensate for the reduced thickness. This allows ultra-thin glass (75 μm or less) to maintain high impact and puncture resistance despite its thinness by introducing internal compressive stresses that prevent crack propagation
Solution Approach 2:
The patent applies local quality by creating specific compressive stress regions at particular locations on the glass substrate (first and second compressive stress regions with depths of 1-10 μm from opposite surfaces). These localized stress zones provide targeted protection against impact and puncture while maintaining overall thinness for foldability
3Strength
If thicker glass-based sheets are used to improve impact and puncture resistance, then strength is improved, but minimum bend radius increases
Solution Approach 1:
The patent applies chemical strengthening to create compressive stress regions that fundamentally change the mechanical behavior of the glass. This stress modification allows relatively thin glass substrates (10-200 μm) to achieve high impact and puncture resistance comparable to much thicker glass, while maintaining small bend radii for foldability
4Shape
If strengthened ribbons with small minimum bend radii are used, then foldability is improved, but impact and puncture resistance deteriorates
Solution Approach 1:
The patent applies chemical strengthening to modify the stress parameters of the ribbon substrate, creating compressive stress regions that enable both small bend radii and high impact resistance. The chemical strengthening process changes the physical state of the glass, allowing it to flex tightly while resisting impact forces
Solution Approach 2:
The patent creates a composite stress structure within the ribbon by forming multiple compressive stress regions through chemical strengthening. This arrangement of stress zones provides both the flexibility needed for small bend radii and the strength needed for impact and puncture 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
The solution achieves low energy fractures, good folding performance, and good impact and puncture resistance, as evidenced by good pen drop performance, and provides small minimum bend radii, particularly in achieving small minimum bend radii, and/or puncture resistance, particularly in achieving small minimum bend radii, and/or puncture resistance, by reducing (e.g., avoiding) stress concentrations and damage along the bend length of the ribbon at or near its minimum bend radius, and/or puncture resistance, particularly in achieving small minimum bend radii, and/or puncture resistance, by reducing (e.g., avoiding) stress concentrations and damage, especially in achieving small minimum bend radii and good impact and puncture resistance.
Implementation Method 1
low energy fractures may be the result of the reduced thickness of the central portion, which stores less energy for a given maximum tensile stress than a thicker glass portion would
Implementation Method 2
The central portion can comprise a first central compressive stress region extending to a first central depth of compression from the first major surface and a second central compressive stress region extending to a second central depth of compression from the second major surface
Data Source
AI summary
Foldable apparatus can comprise a foldable substrate comprising a substrate thickness and a central portion positioned between a first portion and a second portion. The central portion can comprise a central thickness less than the substrate thickness. A first maximum tensile stress of a first tensile stress region in the first portion and a second maximum tensile stress of the second tensile stress region in the second portion can be less than a third maximum tensile stress of a central tensile stress region in the central portion. Ribbons can comprise a ribbon thickness and a central portion positioned between a first portion and a second portion. The central portion can comprise a first central compressive stress region and a second central compressive stress region. In some embodiments, methods of processing a ribbon can comprise masking the first portion, masking the second portion, and chemically strengthening the central portion.