LAS Crystallized Glass Tinting Reduction via Ion Control
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Solution Overview
Problem
Conventional methods for producing LAS-based crystallized glasses result in tinting issues, particularly yellowish tinting, which compromises transparency and brightness, and there is a need for a less tinted glass with improved whiteness and transparency.
Innovation Solution
The use of rare earth elements and actinoid elements, such as Sc, Y, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, and U, with controlled concentrations of V and Cr, along with Y, to reduce tinting and enhance whiteness and transparency in LAS-based crystallizable and crystallized glasses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If As2O3 or Sb2O3 is used as a fining agent, then a large amount of fining gas is produced during melting, but the glass and environment are contaminated due to high toxicity
Solution Approach 1:
The patent extracts and eliminates the harmful fining agents As2O3 and Sb2O3 from the glass composition, replacing them with non-toxic alternatives that do not cause environmental contamination while maintaining fining efficiency
Solution Approach 2:
The patent uses SnO2 as a replaceable fining agent that can be effectively removed through reduction treatment, serving as a temporary substance that fulfills the fining function during melting but can be eliminated in the final product
2Object-affected harmful factors
If SnO2 is used as a fining agent, then environmental contamination is avoided, but the crystallized glass takes on a more yellowish tint due to TiO2, Fe2O3 and other components
Solution Approach 1:
The patent extracts and removes the harmful yellowish tint caused by SnO2 through reduction treatment, eliminating the adverse effect while preserving the beneficial environmental safety aspect of using SnO2 as a fining agent
Solution Approach 2:
The patent converts the harmful yellowish tinting effect of SnO2 into a beneficial outcome by applying reduction treatment that transforms the colored Sn4+ ions into colorless or lightly colored Sn2+ ions, thereby turning a disadvantage into an advantage
3Illumination intensity
If TiO2 content is reduced to remedy tinting, then yellowish tinting is decreased, but the optimal firing temperature range is narrowed and the amount of crystal nuclei produced is reduced
Solution Approach 1:
The patent introduces ZrO2 as an intermediary substance that compensates for the reduced TiO2 content, serving as a substitute nucleating agent that maintains crystal nucleus formation while allowing TiO2 to be reduced for improved transparency
4Manufacturing precision
If ZrO2 content is increased to make up for shortage in crystal nuclei production, then the amount of crystal nuclei is increased, but coarse crystals concurrently precipitate making the glass cloudy
Solution Approach 1:
The patent changes the concentration parameters of both ZrO2 and SnO2 to optimal levels, where ZrO2 is sufficient to provide crystal nuclei but SnO2 reduction treatment prevents excessive coarse crystal formation, achieving a balance between nucleation and transparency
Solution Approach 2:
The patent implements a feedback mechanism through reduction treatment that monitors and corrects the crystal growth process, preventing coarse crystal formation by reducing colored ions that would otherwise promote excessive crystal growth and cloudiness
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
This approach results in a less tinted LAS-based crystallized glass with high whiteness and transparency, suitable for various applications, including front windows and high-technology substrates, by effectively managing the content of transition metals, rare earth elements, and actinoid elements during the glass production process.
Implementation Method 1
The use of rare earth elements and actinoid elements, such as Sc, Y, La, Ce, Pr, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, and U, with controlled concentrations of V and Cr, along with Y, to reduce tinting and enhance whiteness and transparency
Implementation Method 2
it is necessary to melt a glass batch at high temperatures above 1400° C.
Implementation Method 3
by appropriately controlling the heat treatment condition in a crystallization step, the type of crystals to be precipitated in a LAS-based crystallized glass can be controlled
Data Source
AI summary
An object of the present invention is to provide a less tinted LAS system crystallized glass. In the present invention, a content of each of V and Cr in the LAS system crystallized glass is 0 to 3 ppm and a content of each of Sc, La, Ce, Pr, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, Lu, Ac, Th, Pa, and U is 0 to 10 ppm.