Optical Glass Composition for Devitrification Resistance
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Solution Overview
Problem
High-refractive-index optical glasses face challenges in maintaining devitrification resistance both in the molten state and during reheating, with existing glasses either excelling in one aspect but failing in the other, leading to potential devitrification issues in optical elements.
Innovation Solution
An optical glass composition comprising 15-37% B2O3 and SiO2, 15-45% TiO2, Nb2O5, and ZrO2, with specific mass ratios and additional oxides, ensuring a refractive index of 1.78-1.84 and Abbe's number of 26-32, which stabilizes the glass against devitrification by controlling liquidus and glass transition temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If the glass composition is optimized for high refractive index, then the refractive index increases, but the devitrification resistance in molten state deteriorates
Solution Approach 1:
The patent applies parameter changes by precisely controlling the chemical composition ratios of multiple oxides (B2O3, SiO2, TiO2, Nb2O5, ZrO2, BaO, SrO, CaO, MgO, K2O, Na2O, Li2O) within specific ranges. This composition optimization achieves a refractive index of 1.70 or more while maintaining devitrification resistance in the molten state, resolving the contradiction between high refractive index and devitrification resistance.
2Illumination intensity
If the glass composition is optimized for high refractive index, then the refractive index increases, but the devitrification resistance during reheating deteriorates
Solution Approach 1:
The patent uses parameter changes by adjusting the specific content ranges of network formers (B2O3, SiO2), high-refractive-index oxides (TiO2, Nb2O5, ZrO2), and network modifiers (BaO, SrO, CaO, MgO, K2O, Na2O, Li2O). This compositional parameter optimization achieves both high refractive index (1.70 or more) and excellent devitrification resistance during reheating, as evidenced by a large separation between liquidus temperature (1000-1150°C) and processing temperature.
3Ease of manufacture
If conventional glass compositions are used, then manufacturing is simpler, but both devitrification resistances cannot be improved simultaneously
Solution Approach 1:
The patent applies composite materials by creating a multi-component glass system that combines network formers (B2O3, SiO2), high-refractive-index oxides (TiO2, Nb2O5, ZrO2), and network modifiers (BaO, SrO, CaO, MgO, K2O, Na2O, Li2O) in specific proportions. This composite composition achieves both high refractive index and dual devitrification resistance, overcoming the limitations of conventional single-component or simpler glass systems.
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 glass exhibits excellent devitrification resistance in both molten and reheated states, facilitating the production of high-quality, transparent optical elements with improved thermal stability and optical properties.
Implementation Method 1
the glass may be undesirably devitrified while the molten glass is quenched and molded. Further, if only the devitrification resistance at the time of molding the glass from the molten state is excellent but devitrification resistance at the time of reheating, softening and molding a glass material
Data Source
AI summary
Provided are an optical glass with a high refractive index which has excellent devitrification resistance both in a molten state and during reheating, and a glass material for press molding and an optical element which are comprised of the optical glass. This optical glass includes, in mass %, 15-37% of B2O3 and SiO2 in total, 15-45% of TiO2, Nb2O5 and ZrO2 in total, and 12-40% of BaO, SrO, CaO, MgO, K2O, Na2O and Li2O in total, has a mass ratio (B2O3/(B2O3+SiO2)) of 0.15 or more, a mass ratio (TiO2/(TiO2+Nb2O5+ZrO2)) of 0.01 to 0.8, a mass ratio ((BaO+SrO+CaO)/(BaO+SrO+CaO+MgO+K2O+Na2O+Li2O)) of 0.4 or more, and a mass ratio ((K2O+Na2O+Li2O)/(BaO+SrO+CaO+MgO+K2O+Na2O+Li2O)) of 0.1 or more, substantially does not include PbO, and has a refractive index nd of 1.78-1.84, and an Abbe's number νd of 26-32.