Phosphate Optical Glass Mold Press Molding Devitrification
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Solution Overview
Problem
Conventional optical glasses for mold press molding face challenges such as high glass-transition and liquidus temperatures, leading to difficulties in quality control, prolonged processing times, and devitrification, especially when using glasses with high ZnO content, which compromises low dispersibility essential for chromatic aberration correction.
Innovation Solution
A phosphate glass composition with specific ranges of B2O3, P2O5, Al2O3, Li2O, MgO, CaO, SrO, BaO, Na2O, K2O, ZnO, Y2O3, Gd2O3, and La2O3 is developed, optimizing refractive index, dispersion, glass-transition temperature, and devitrification resistance to enhance moldability and chromatic aberration correction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional optical glass with high ZnO content is used to reduce glass-transition temperature, then moldability is improved, but dispersibility deteriorates compromising chromatic aberration correction
Solution Approach 1:
The patent changes the chemical composition parameters by limiting ZnO to 12% or less and introducing specific amounts of B2O3 (10-25%), P2O5 (30-60%), and rare earth oxides. This parameter adjustment resolves the contradiction by achieving low glass-transition temperature (≤530°C) through B2O3 and P2O5 while maintaining low dispersibility through the balanced composition and rare earth oxide additions.
Solution Approach 2:
The patent creates a composite glass system combining multiple oxide components (B2O3, P2O5, Al2O3, rare earth oxides, and limited ZnO) to achieve properties that individual components cannot provide alone. The synergistic combination allows simultaneous achievement of low melting temperature, low dispersibility, and good moldability.
2Manufacturing precision
If glass with high glass-transition temperature is used, then optical quality is maintained, but processing time increases and quality control becomes difficult
Solution Approach 1:
The patent changes the glass composition parameters to include B2O3 (10-25%) and P2O5 (30-60%) which significantly lower the glass-transition temperature to ≤530°C. This enables faster processing and better quality control while maintaining optical quality through the balanced composition and controlled ZnO content (≤12%).
3Stability of the object's composition
If glass with high liquidus temperature is used for hot-molding, then structural stability is improved, but devitrification occurs during molding
Solution Approach 1:
The patent adjusts the composition parameters by limiting ZnO to ≤12% and adding specific amounts of B2O3, P2O5, and rare earth oxides. This creates a glass composition with liquidus temperature ≤1000°C that prevents devitrification during hot-molding while maintaining structural stability through the balanced multi-component system.
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 a refractive index of 1.56-1.61, Abbe's number of 63-70, glass-transition temperature ≤530°C, and liquidus temperature ≤1000°C, ensuring ease of molding, preventing devitrification, and maintaining optical quality, making it suitable for mold press molding and hot-molding of preforms.
Implementation Method 1
glass-transition temperature (Tg) of raw materials are higher
Implementation Method 2
liquidus temperature (Tl) of glass is high
Implementation Method 3
in case that the liquidus temperature (Tl) of glass is high, devitrification tend to occur during molding
Data Source
AI summary
Provided is optical glass which is suitable for mold press molding. Optical glass according to the present invention is characterized by containing, in weight%, 10-25% of B2O3, 30-60% of P2O5, 0-5% of Al2O3, 0.1-10% of Li2O, 0-15% of SrO, 10-50% of BaO, 0-12% of ZnO, 0-5% of Y2O3 and 0-5% of Gd2O3, while not containing La2O3.