Glass Composition for Foldable Display Substrate Flexibility
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Solution Overview
Problem
Existing glass substrates used in display devices, particularly in foldable devices, face challenges in balancing thinness for bending stress relief and strength to withstand external impacts, leading to potential creasing and brittleness issues.
Innovation Solution
A glass composition with specific ratios of SiO2, Al2O3, Na2O, K2O, and RO, along with optional Li2O, is formulated to achieve a low Young's modulus, enabling a glass substrate with a thickness of 30-60 μm, thermal expansion coefficient of 90-200*10−7/K, and Young's modulus of 45-70 GPa, enhancing flexibility and impact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the glass substrate is made thinner to alleviate bending stress in foldable devices, then flexibility is improved, but strength to withstand external impacts deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the glass substrate by incorporating specific amounts of PbO (5-20 wt%), MgO (3-15 wt%), CaO (5-20 wt%), and other oxides in controlled ratios. This compositional parameter adjustment reduces the Young's modulus to 45-70 GPa while maintaining adequate strength, enabling the glass to be thinner (30-60 μm) without sacrificing impact resistance.
2Weight of moving object
If the glass substrate is made thinner to reduce bending stress, then portability is improved, but brittleness increases leading to creasing issues
Solution Approach 1:
The patent creates a composite glass material system combining multiple oxide components (PbO, MgO, CaO, Al2O3, SiO2, B2O3, etc.) in specific proportions. This composite composition achieves a balanced mechanical property profile where the Young's modulus is reduced to 45-70 GPa, preventing crease formation in thin (30-60 μm) substrates while maintaining overall structural reliability for portable applications.
Data Source
AI summary
A glass composition includes 55 mol % to 70 mol % of SiO2, 0 mol % to 10 mol % of Al2O3, 5 mol % to 20 mol % of Na2O, 5 mol % to 20 mol % of K2O, and 0 mol % to 15 mol % of RO, wherein R includes at least one selected from among Pb, Mg, Ca, Ba, and Sr.