Optical Glass Composition for High Refractive Index and Devitrification Resistance
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Solution Overview
Problem
High refractive index and low dispersion optical glasses are prone to devitrification and difficult to mass produce due to the crystallization issues caused by high lanthanide oxide content, which complicates the production process.
Innovation Solution
The optical glass composition is optimized by controlling the content and ratio of La2O3, Gd2O3, and Ta2O5 in the B—La—Zr—Ta formula system, along with other components like B2O3, SiO2, ZrO2, and TiO2, to achieve a refractive index greater than 1.87 and an Abbe number greater than 38.0, while maintaining a lower upper crystallization temperature and improving devitrification resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If more lanthanide oxides are introduced to improve refractive index, then the refractive index increases, but the glass becomes prone to crystallization and devitrification, raising upper crystallization temperature and complicating mass production
Solution Approach 1:
The patent optimizes the content proportions of lanthanide oxides (La2O3, Gd2O3, Y2O3, Yb2O3) within specific ranges (50-75% total) and controls the weight ratio of La2O3 to Gd2O3 (1.28-1.625), while adjusting Ta2O5 content (0.5-10%) to achieve the desired refractive index (nd>1.87) and Abbe number (vd>38.0) without excessive crystallization temperature increase
Solution Approach 2:
The patent creates a composite glass system combining B2O3, SiO2, ZrO2, TiO2, and multiple lanthanide oxides with Ta2O5, where each component contributes specific properties. This composite formulation achieves high refractive index and low dispersion while maintaining glass forming ability and controlling upper crystallization temperature below 1350°C
2Illumination intensity
If more lanthanide oxides are introduced to improve refractive index, then the refractive index increases, but the upper crystallization temperature increases, making the glass easier to crystallize
Solution Approach 1:
The patent carefully controls the total content of lanthanide oxides (50-75%) and the specific ratio of La2O3 to Gd2O3 (1.28-1.625), combined with Ta2O5 content (0.5-10%), to achieve refractive index nd>1.87 while keeping upper crystallization temperature below 1350°C, preventing excessive crystallization tendency
3Illumination intensity
If the glass formula is optimized for high refractive index and low dispersion, then optical performance improves, but devitrification resistance decreases
Solution Approach 1:
The patent formulates a composite glass system with B2O3 (5-25%), SiO2 (0.5-15%), ZrO2 (1-15%), TiO2 (0.5-10%), and controlled lanthanide oxides with Ta2O5 (0.5-10%), where the synergistic interaction among components achieves high refractive index (nd>1.87) and low dispersion (vd>38.0) while maintaining devitrification resistance through appropriate composition balance
Data Source
AI summary
Disclosed are optical glass, a glass preform or an optical element made therefrom the same and an optical instrument. The optical glass is calculated by a mass percentage content relative to a total mass of glass converted by an oxide, and the optical glass includes: B2O3: 5˜25%, SiO2: 0.5˜15%, ZrO2: 1˜15%, TiO2: 0˜10%, Ta2O5: 0.5˜10%, and La2O3, Gd2O3, Y2O3 and Yb2O3 of which the sum is 50˜75%, and Nb2O5 is not contained, a weight ratio of La2O3 to Gd2O3, i.e., La2O3/Gd2O3, is 1.28˜1.625.