High Refractive Index Thin Glass via BaO-TiO2-Nb2O5 Composition
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Solution Overview
Problem
Conventional optical glasses with high refractive indexes are not suitable for flat glass manufacturing methods due to their tendency to crystallization and chemical composition requirements, leading to processability issues and suboptimal surface conditions when trying to produce thin glasses with high refractive indexes.
Innovation Solution
Development of thin glasses with refractive indexes greater than 1.60, produced using flat glass manufacturing methods such as down draw and overflow fusion, which incorporate specific chemical compositions like BaO, TiO2, and SiO2 to balance refractive index and crystallization resistance, resulting in fire-polished surfaces with low roughness and improved chemical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If conventional optical glasses with high refractive indexes are used, then refractive index is improved, but tendency to crystallization increases and processability deteriorates
Solution Approach 1:
The patent changes the chemical composition parameters of the glass, specifically limiting TiO2 to 13-30 wt%, Nb2O5 to 2-20 wt%, and BaO to 5-14.5 wt%, while adjusting SiO2 to 25-50 wt%. This parameter optimization balances refractive index enhancement with crystallization resistance, allowing the glass to achieve nd>1.60 while maintaining stability during flat glass manufacturing processes.
Solution Approach 2:
The patent creates a composite glass system combining multiple oxide components (SiO2, B2O3, TiO2, Nb2O5, BaO, and alkali metal oxides) in specific proportions. This composite formulation synergistically achieves high refractive index through TiO2 and Nb2O5 while SiO2 and B2O3 provide structural stability and crystallization resistance, resolving the contradiction between optical performance and processability.
2Ease of manufacture
If conventional optical glasses are produced using flat glass manufacturing methods, then production cost is reduced, but surface quality deteriorates due to poor processability
Solution Approach 1:
The patent optimizes chemical composition parameters to enable successful flat glass manufacturing. By adjusting the glass formula to include specific ranges of TiO2 (13-30%), Nb2O5 (2-20%), and BaO (5-14.5%), the glass achieves appropriate melting characteristics, viscosity profile, and surface tension, allowing it to be processed by conventional flat glass methods while maintaining excellent surface quality with fire-polished finish and low roughness.
Solution Approach 2:
The patent converts the potential harm of high refractive index components (which typically cause poor processability) into benefit by carefully controlling their concentrations. The optimized formulation allows the high-refractive-index oxides to enhance optical performance while their controlled amounts prevent processing defects, turning what would be a harmful composition into a beneficial, manufacturable glass system.
3Illumination intensity
If high amounts of lead oxide are added to achieve high refractive indexes, then refractive index is improved, but ecological compatibility and economic efficiency deteriorate
Solution Approach 1:
The patent extracts and eliminates lead oxide from the glass composition entirely, replacing it with environmentally friendly alternative oxides. By using TiO2, Nb2O5, and BaO in optimized proportions, the patent achieves high refractive index (nd>1.60) without lead, thereby improving ecological compatibility and economic efficiency while maintaining optical performance.
Solution Approach 2:
The patent changes the chemical composition by substituting lead oxide with alternative oxide combinations. The specific parameter ranges of TiO2 (13-30%), Nb2O5 (2-20%), and BaO (5-14.5%) are optimized to achieve the refractive index enhancement previously provided by lead, but with improved ecological and economic characteristics suitable for modern manufacturing.
Data Source
AI summary
Glass sheets with high refractive indexes (nd), layer composite assemblies including the glass sheets, methods for manufacturing the glass sheets, and methods of using the glass sheets are all provided. The glass sheets can be processed in a glass sheet manufacturing process and nevertheless have the optical properties of a classical optical glass. The glass sheets of the are highly transparent, resistant to crystallization, chemically resistant and highly refractive. The glass sheets have a viscosity-temperature behavior that is adapted to the manufacturing procedure with glass sheet manufacturing processes.