Optical Glass Composition for Devitrification Resistance
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Solution Overview
Problem
High refractive index, high dispersion glasses used in optical elements often devitrify during the reheat press molding process due to low thermal stability, making them unsuitable for producing bonded lenses.
Innovation Solution
A high refractive index, high dispersion optical glass with a specific composition that includes SiO2, B2O3, GeO2, Li2O, Na2O, K2O, CaO, SrO, BaO, TiO2, Nb2O5, and WO3, offering improved thermal stability and resistance to devitrification, allowing for successful reheat press molding without devitrification.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Illumination intensity
If high refractive index, high dispersion glass is used in reheat press molding, then optical performance is improved, but thermal stability deteriorates causing devitrification
Solution Approach 1:
The patent modifies the chemical composition parameters of the glass by adjusting the content ranges of specific oxides (SiO2: 2-37%, B2O3: 0-25%, TiO2: 15-55%, Nb2O5: 0-20%, WO3: 0-20%, and metal oxide: 0.1-5%) to achieve a balance between high refractive index (1.82-2.00) and thermal stability that prevents devitrification during reheat press molding
Solution Approach 2:
The patent creates a composite glass material that combines multiple oxide components in specific proportions, forming a complex glass system that simultaneously achieves high refractive index, high dispersion (Abbé number 20-30), and sufficient thermal stability for reheat press molding processes
2Ease of manufacture
If precision mold press molding method is used, then manufacturing cost is reduced, but bonding precision deteriorates
Solution Approach 1:
The patent performs preliminary polishing of the bonding surfaces to spherical convex and concave shapes before the press molding process, ensuring that when the molded articles are bonded together, the surfaces align precisely without requiring post-molding grinding or polishing, thus achieving both cost efficiency and bonding precision
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 optical glass provides high thermal stability, preventing devitrification during reheat press molding and enabling the production of bonded lenses with enhanced functionality and compactness in optical systems.
Implementation Method 1
a high refractive index, high dispersion optical glass that has good thermal stability such that it does not devitrify even in the reheat pressing method
Data Source
AI summary
An aspect of the present invention relates to an optical glass, which comprises, denoted as weight percent, 2 to 37 percent of SiO2, 0 to 25 percent of B2O3, 0 to 10 percent of GeO2, 18 to 55 percent of a combined content of Li2O, Na2O, K2O, CaO, SrO, and BaO, and 27 to 55 percent of a combined content of TiO2, Nb2O5, and WO3, wherein the weight ratio of SiO2 content relative to a combined content of SiO2 and B2O3 ranges from 0.1 to 1, a weight ratio of the Li2O content to a combined content of Li2O, Na2O, K2O, CaO, SrO, and BaO ranges from 0 to 0.4, and a weight ratio of TiO2 content relative to a combined content of TiO2, Nb2O5, and WO3 ranges from 0.35 to 1, with a refractive index nd of 1.860 to 1.990 and an Abbé number νd of 21 to 29.