Foldable Glass Cover Modules with Impact Resistance
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Solution Overview
Problem
Flexible electronic devices face challenges in achieving optimal optical transparency, thermal stability, fatigue resistance, and puncture resistance, especially when folded, due to the limitations of traditional materials like metal foils and polymeric foils, and the complex stress states in glass-containing modules lead to delamination and cohesive failures.
Innovation Solution
The development of foldable electronic device modules with a glass-containing cover element, optimized through control of material properties, thicknesses, adhesives, and interlayers, which include a glass layer with compressive stress regions and tailored elastic moduli to enhance impact resistance, bending resistance, and puncture resistance, allowing for easier folding and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If glass substrates are manufactured to very low thickness levels (150 μm) to achieve flexibility, then flexibility and thinness are improved, but fatigue resistance and mechanical reliability upon bending deteriorate
Solution Approach 1:
The patent employs a composite structure consisting of a glass substrate combined with a polymeric foil layer and adhesive layers. This composite construction allows the glass to provide optical transparency and thermal stability while the polymeric foil contributes flexibility and fatigue resistance, resolving the contradiction between thinness and mechanical reliability
Solution Approach 2:
The patent optimizes the thickness parameters of multiple layers including the glass substrate, polymeric foil, and adhesive layers. By carefully controlling these thickness parameters, the module achieves both flexibility for folding and sufficient mechanical strength to prevent fatigue failure during repeated bending cycles
2Adaptability or versatility
If multiple layers and adhesives are added to create glass-containing modules with electronic components, then functionality and integration are improved, but stress concentration and susceptibility to delamination failure increase
Solution Approach 1:
The patent uses adhesives with optimized mechanical properties that create a homogeneous stress distribution across the interface between layers. The adhesive composition and thickness are carefully controlled to ensure uniform bonding, reducing stress concentration points that would lead to delamination failure
Solution Approach 2:
The patent employs a multi-layer composite structure where each layer (glass substrate, polymeric foil, adhesives, electronic components) is specifically designed and selected to complement the others. The composite construction allows stress management across the entire module, preventing delamination while maintaining functional integration
3Ease of operation
If traditional polymeric foils are used for flexibility, then ease of bending and impact resistance are improved, but optical transparency and thermal stability deteriorate
Solution Approach 1:
The patent creates a composite structure where a glass substrate provides superior optical transparency and thermal stability, while a polymeric foil layer contributes flexibility and ease of bending. The combination allows the module to achieve properties that neither material could provide alone
4Ease of manufacture
If traditional polymeric foils are used for flexibility, then low cost and impact resistance are improved, but thermal stability and hermeticity deteriorate
Solution Approach 1:
The patent combines a glass substrate with superior thermal stability and hermeticity properties with a polymeric foil layer that provides cost-effectiveness and impact resistance. This composite approach allows the module to achieve thermal performance comparable to glass while maintaining cost advantages through the use of polymeric 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 provides enhanced impact resistance, reduced tensile stresses, and increased bending resistance, leading to improved mechanical reliability and manufacturability of foldable electronic devices, enabling them to withstand small bend radii and puncture without delamination or cohesive failures.
Implementation Method 1
a glass-containing cover element (50), optimized through control of material properties, thicknesses, adhesives, and interlayers, which include a glass layer with compressive stress regions
Implementation Method 2
optimized through control of material properties, thicknesses, adhesives, and interlayers
Implementation Method 3
flexible electronic device substrate (60)... allowing for easier folding and reliability
Implementation Method 4
The solution provides enhanced impact resistance, reduced tensile stresses, and increased bending resistance
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A foldable electronic device module includes: a glass-containing cover element having a thickness from about (25) µm to about (200) µm, an elastic modulus from about (20) to (140) GPa, and first and second primary surfaces; a stack comprising: (a) an interlayer having an elastic modulus from about (0.01) to (10) GPa and a thickness from about 50 to (200) µm, and (b) a flexible substrate having a thickness from about (100) to (200) µm; and a first adhesive joining the stack to the cover element, and comprising an elastic modulus from about (0.001) to (10) GPa and a thickness from about (5) to (25) µm. Further, the module comprises an impact resistance characterized by tensile stresses of less than about (4100) MPa and less than about (8300) MPa at the first and second primary surfaces of the cover element, respectively, upon an impact in a Pen Drop Test.