Optical Glass Composition for High Refractive Index
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Solution Overview
Problem
The challenge is to develop an optical glass with a high refractive index and low dispersion, specifically within the range of 1.78-1.95 and Abbe number of 32-50, without using GeO2 to prevent devitrification, while maintaining cost-effectiveness and improving glass stability.
Innovation Solution
The optical glass composition includes 1-20% Si4+, 25-60% B3+, 10-40% La3+, 0-15% Y3+, with a total of La3+, Y3+, Gd3+, and Yb3+ being 20-55%, and specific ratios of other cations to achieve the desired refractive index and Abbe number, ensuring stability and low dispersion without GeO2.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If more ingredients with high refractive index are given to glass in the formulation system, then the refractive index and Abbe number are improved, but the glass stability is reduced and the glass devitrifies in the manufacturing process
Solution Approach 1:
The patent applies parameter changes by precisely controlling the composition ratios of multiple oxide components. Specifically, it limits B2O3 to 25-60% and SiO2 to 10-40%, while controlling rare earth oxides (La2O3, Y2O3, Gd2O3, Yb2O3) at 10-40% each. The patent also introduces small amounts of Nb2O5 (0-15%), TiO2 (0-10%), Ta2O5 (0-10%), and WO3 (0-5%) to fine-tune the refractive index and Abbe number while maintaining glass stability through these constrained parameter ranges.
Solution Approach 2:
The patent creates a composite glass formulation by combining multiple oxide components with complementary functions. The base network formers (B2O3, SiO2) provide structural stability, while rare earth oxides (La2O3, Y2O3, Gd2O3, Yb2O3) contribute to high refractive index and low dispersion. Additional metal oxides (Nb2O5, TiO2, Ta2O5, WO3) are incorporated as modifiers to adjust optical properties without compromising glass stability, creating a multi-component composite system where each ingredient serves a specific function.
2Reliability
If the content of B2O3 and SiO2 as network formers is higher, then the glass stability is improved, but the refractive index nd of the optical glass is reduced
Solution Approach 1:
The patent applies parameter changes by optimizing the balance between network formers and optical modifiers. It sets B2O3 at 25-60% and SiO2 at 10-40% to maintain glass stability, while simultaneously introducing rare earth oxides (La2O3, Y2O3, Gd2O3, Yb2O3) at controlled levels of 10-40% each to achieve high refractive index (nd=1.78-1.95) and low dispersion (Abbe number vd=32-50). This parameter optimization allows the patent to overcome the traditional trade-off between stability and optical performance.
Solution Approach 2:
The patent introduces intermediary components (Nb2O5, TiO2, Ta2O5, WO3) that act as mediators between the network formers (B2O3, SiO2) and rare earth oxides. These intermediaries help integrate the different components, allowing the network formers to provide stability while the rare earth oxides enhance optical properties. The intermediaries facilitate compatibility between components with different functions, enabling the simultaneous achievement of high refractive index and glass stability.
3Measurement precision
If GeO2 is introduced to improve refractive index, then the optical properties are improved, but the cost of the raw material increases
Solution Approach 1:
The patent replaces expensive GeO2 with more cost-effective rare earth oxides (La2O3, Y2O3, Gd2O3, Yb2O3) and common metal oxides (Nb2O5, TiO2, Ta2O5, WO3). These alternative materials achieve the same high refractive index (nd=1.78-1.95) and low dispersion (Abbe number vd=32-50) properties at lower cost. The patent eliminates GeO2 entirely, using economical alternatives that provide comparable or superior optical performance.
Solution Approach 2:
The patent changes the compositional parameters by substituting the GeO2-based formulation with a rare earth oxide-based formulation. Instead of relying on GeO2 to achieve high refractive index, the patent uses controlled combinations of La2O3 (10-40%), Y2O3 (0-15%), Gd2O3 (0-10%), and Yb2O3 (0-10%), along with small amounts of Nb2O5, TiO2, Ta2O5, and WO3. This parameter change from GeO2 to rare earth oxides maintains optical performance while reducing material cost.
Data Source
AI summary
An optical glass with high refractive index and low dispersion, having refractive index nd of 1.78-1.95, Abbe number νd of 32-50, and contains no GeO2, so it is not easily devitrified. An optical glass, represented by cation %, including: 1-20% of Si4+; 25-60% of B3+; 10-40% of La3+; 0-15% of Y3+; 0-20% of Nb5+; 0-15% of Ti4+; 0-10% of Ta5+; 0-5% of W6+; 0-15% of Zr4+; 0-10% of Zn2+; 0-10% of Bi3+. An optical glass with excellent transmittance, an optical glass preform and an optical element formed by the above optical glass. The optical element made by the above optical glass and the above glass preform or optical element blank, such as lens, can be used for optical systems.