Optical Glass Composition for High Refractive Index and Low Specific Gravity
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Solution Overview
Problem
There is a demand for optical glass with a high refractive index and low specific gravity, as existing high-refractive-index optical glasses have specific gravities that are too high for use in augmented reality devices like goggle-type display devices.
Innovation Solution
The development of optical glass with specific compositions, including refractive index nd of 1.950 or more, P2O5 between 10.0 to 40.0 mass %, TiO2 between 5.0 to 40.0 mass %, Nb2O5 between 20.0 to 60.0 mass %, Bi2O3 20.0 mass % or less, total Al2O3 and SiO2 2.0 mass % or less, total Li2O, Na2O, and K2O 5.0 mass % or less, and total ZnO, SrO, and BaO 0.01 to 12.0 mass %, which balances refractive index and specific gravity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high-refractive-index optical glass containing Ti and Nb is used, then the refractive index is improved, but the specific gravity becomes too large
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios of multiple oxides in the glass. Specifically, it limits TiO2 to 5-40 mass%, Nb2O5 to 20-60 mass%, and introduces P2O5 at 10-40 mass%, while constraining other components like Bi2O3 to 20 mass% or less and ZnO+SrO+BaO to 0.01-12.0 mass%. This compositional parameter optimization achieves a refractive index of 1.950 or more while maintaining specific gravity at 4.20 or less, resolving the contradiction between high refractive index and low specific gravity
Solution Approach 2:
The patent creates a composite glass material system combining multiple oxide components with specific functional roles. TiO2 and Nb2O5 provide high refractive index, P2O5 contributes to network formation and lowers specific gravity, Bi2O3 enhances refractive index within limits, and ZnO/SrO/BaO improve chemical durability. This multi-component composite approach allows simultaneous optimization of refractive index and specific gravity that cannot be achieved with single-component glasses
2Weight of moving object
If the specific gravity is reduced while maintaining high refractive index, then the weight is improved, but the thermal stability and chemical durability may be compromised
Solution Approach 1:
The patent uses parameter changes to optimize the balance between specific gravity and material stability. By controlling P2O5 at 10-40 mass% and limiting Bi2O3 to 20 mass% or less, the glass achieves low specific gravity while maintaining thermal stability. The constrained amounts of ZnO, SrO, and BaO (total 0.01-12.0 mass%) further ensure chemical durability without significantly increasing specific gravity, resolving the contradiction between weight reduction and reliability maintenance
Data Source
AI summary
Provided is optical glass in which a refractive index nd is 1.950 or more, an amount of P2O5 is 10.0 to 40.0 mass %, an amount of TiO2 is 5.0 to 40.0 mass %, an amount of Nb2O5 is 20.0 to 60.0 mass %, an amount of Bi2O3 is 20.0 mass % or less, a total amount of Al2O3 and SiO2 [Al2O3+SiO2] is 2.0 mass % or less, a total amount of Li2O, Na2O, and K2O [Li2O+Na2O+K2O] is 5.0 mass % or less, and a total amount of ZnO, SrO, and BaO [ZnO+SrO+BaO] is 0.01 to 12.0 mass %.