Flexible Substrate Protective Assembly for Impact Resistance
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Solution Overview
Problem
Touch panels in electronic devices face challenges in durability, particularly in anti-drop and anti-impact design, as existing solutions like sapphire substrates are prone to cracking and lack flexibility.
Innovation Solution
A protective assembly comprising a cover plate, a transparent polymer buffer layer with high light transmittance and Poisson's ratio, and a flexible substrate doped with inorganic compounds like graphene, which provides elasticity and high Young's coefficient, along with a composite touch electrode pattern layer to maintain touch functionality and reduce impedance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If sapphire substrate is used to increase hardness and wear resistance, then impact resistance is improved, but flexibility is lost and cracks occur
Solution Approach 1:
The patent replaces the rigid sapphire substrate with a flexible substrate that has high Young's modulus (1-10 GPa) and incorporates inorganic compounds such as graphene (100-1000 ppm). This flexible substrate maintains structural integrity under impact while providing necessary flexibility, resolving the contradiction between impact resistance and flexibility that plagues traditional sapphire-based solutions.
Solution Approach 2:
The patent creates a composite structure combining organic buffer layer materials (polymer, epoxy, polyimide) with inorganic compounds (graphene, diamond). This composite approach achieves both the hardness and wear resistance of inorganic materials and the flexibility of organic materials, simultaneously improving impact resistance while maintaining adaptability.
2Strength
If buffer layer thickness is increased to improve impact absorption, then impact resistance is improved, but light transmittance decreases
Solution Approach 1:
The patent optimizes the buffer layer thickness to a specific range (3-15 μm) that balances impact absorption capability with light transmittance requirements. Additionally, the buffer layer is designed with high Poisson's ratio (>0.4) and high elongation (200-1600%) to maximize impact absorption efficiency within the constrained thickness, maintaining >85% light transmittance while providing adequate impact protection.
3Reliability
If Young's coefficient of flexible substrate is increased to improve impact resistance, then durability is improved, but manufacturing complexity increases
Solution Approach 1:
The patent specifies a targeted Young's modulus range (1-10 GPa) for the flexible substrate, which is high enough to provide durability and impact resistance but low enough to maintain flexibility and manufacturability. This parameter optimization ensures the substrate can be processed using conventional flexible substrate manufacturing techniques while achieving the desired mechanical properties.
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 effectively resists impacts, maintains touch functionality, and increases touch refresh rate by combining the elasticity of the buffer layer with the high Young's coefficient of the flexible substrate, while the composite touch electrode reduces impedance.
Implementation Method 1
The buffer layer has a Poisson's ratio greater than about 0.4 and an elongation ranging from about 200% to about 1600%, enabling it to absorb impact energy through elastic deformation
Implementation Method 2
The buffer layer has a Poisson's ratio greater than about 0.4, which characterizes its elastic deformation behavior under stress
Implementation Method 3
The flexible substrate has a thickness ranging from about 3 μm to about 10 μm and a Young's coefficient ranging from about 1 GPa to about 10 GPa, enabling it to resist impact forces while maintaining flexibility
Implementation Method 4
The flexible substrate is doped with an inorganic compound, including graphene, diamond, or a mixture thereof, with graphene oxide ranging from about 100 ppm to about 1000 ppm, which enhances its mechanical properties
Data Source
AI summary
A protective assembly includes a cover plate, a buffer layer, and a flexible substrate. The buffer layer is disposed on the cover plate and made of transparent polymer. The buffer layer has a light transmittance greater than about 85%, a thickness ranging from about 3 μm to about 15 μm, and a Poisson's ratio greater than about 0.4. The flexible substrate is disposed on the buffer layer and doped with an inorganic compound. The flexible substrate has a thickness ranging from about 3 μm to about 10 μm and a Young's coefficient ranging from about 1 GPa to about 10 GPa.