Layered Bendable Glass with Sliding Interface
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Solution Overview
Problem
Conventional flexible glass materials lack suitable fatigue resistance and mechanical reliability upon bending, making them unsuitable for flexible substrate and display applications in electronic devices, which require puncture resistance, thermal stability, and optical transparency.
Innovation Solution
A layered glass article composed of ultra-thin glass layers that mimic a monolithic layer in puncture resistance but can bend to a tight radius, with anti-frictive coatings allowing the layers to slide past each other, maintaining structural integrity and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single ultra-thin glass layer is used, then the glass can bend to a tight radius, but the puncture resistance is insufficient
Solution Approach 1:
The glass structure is divided into multiple ultra-thin glass layers (each 15-100 micrometers thick) stacked together. Each individual layer maintains the ability to bend to tight radii, while the stack of multiple layers collectively provides enhanced puncture resistance through distributed structural support and energy absorption across layers.
Solution Approach 2:
The invention creates a composite glass structure by stacking multiple ultra-thin glass layers with intermediate bonding layers. This composite structure combines the flexibility of individual thin layers with the strength of a multi-layer assembly, achieving both tight bend radius capability and high puncture resistance that neither single-layer configuration could achieve alone.
2Strength
If multiple glass layers are stacked, then the puncture resistance increases, but the ability to bend to tight radius decreases
Solution Approach 1:
The intermediate layers between glass layers have locally optimized properties: they provide sufficient bonding strength to maintain structural integrity during bending, while simultaneously having low friction characteristics that allow layers to slide relative to each other. This local differentiation enables the stack to bend to tight radii while maintaining puncture resistance.
Solution Approach 2:
The glass layer stack is designed with dynamic characteristics where layers can slide past each other during bending operations. The intermediate bonding layers allow controlled relative motion between glass layers, enabling the structure to adapt its configuration during bending while maintaining overall structural integrity and puncture resistance.
3Ease of operation
If glass layers are allowed to slide during bending, then the bend radius can be tighter, but the structural integrity may be compromised
Solution Approach 1:
Intermediate bonding layers serve as mediators between adjacent glass layers. These intermediate layers provide controlled adhesion that maintains structural integrity while allowing sliding motion during bending. The intermediate layers transfer and distribute stresses uniformly across the stack, preventing stress concentration that could compromise structural integrity during tight bending operations.
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 layered glass structure provides enhanced puncture resistance, higher surface hardness, improved chemical durability, and resistance to warping with bend, while maintaining the ability to bend to a tight radius, surpassing the limitations of single ultra-thin glass layers and monolithic glass of similar thickness.
Implementation Method 1
Anti-friction coatings and/or materials between the ultra-thin glass layers allow the ultra-thin glass layers to slide past each other during bending
Data Source
AI summary
A glass article having a first glass layer, a second glass layer disposed adjacent to the first glass layer, and an interface slidably coupling the first glass layer to the second glass layer. The interface has a thickness of from 2 nm to 500 nm. The glass article is characterized by: (a) an absence of failure when the article is held at a parallel plate separation distance of 10 mm for 60 minutes at 25° C. and 50% relative humidity; (b) a puncture resistance of greater than about 6 kgf when the second glass layer is supported by (i) a 50 μm thick pressure-sensitive adhesive having an elastic modulus of less than 1 GPa and (ii) an approximately 100 μm thick polyethylene terephthalate layer having an elastic modulus of less than 10 GPa, and the first glass layer is loaded with a tungsten carbide ball having a 1 mm diameter.