Titanium-Doped Quartz Glass UV Absorption and Defect Control
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Solution Overview
Problem
Conventional titanium-containing quartz glass for UV applications suffers from defects such as air bubbles, foreign matter inclusions, and impurity-related absorption, which affect its purity, transmittance, and strain resistance, especially in large-sized products.
Innovation Solution
The development of titanium-containing quartz glass with a controlled titanium concentration between 10 ppm and 500 ppm, an OH group concentration between 10 ppm and 350 ppm, and minimal impurities, achieved through a method involving chemical vapor deposition and subsequent heat treatments under controlled atmospheres.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If natural materials such as crystal powder are subjected to electrical melting or oxyhydrogen melting to produce titanium-containing quartz glass, then UV absorption capability is achieved, but air bubbles and foreign matter inclusions are generated, increasing defect rates and making it difficult to produce large-sized products
Solution Approach 1:
The patent changes the production method from conventional melting to chemical vapor deposition, and adjusts key parameters including titanium concentration (10-500 ppm), OH group concentration (10-350 ppm), and impurity levels (Fe, Cu ≤ 50 ppb each). These parameter changes enable UV absorption capability while eliminating air bubbles and foreign matter inclusions, achieving defect-free large-sized quartz glass products
Solution Approach 2:
The patent employs chemical vapor deposition in a controlled inert atmosphere to produce quartz glass, preventing contamination and bubble formation. The process uses high-purity reactants and maintains controlled atmospheric conditions throughout production, ensuring the resulting glass contains no air bubbles or foreign matter inclusions while achieving the required UV absorption properties
2Reliability
If conventional melting methods are used to produce titanium-containing quartz glass, then UV absorption is achieved, but impurity metals such as iron and copper are present in high concentrations, causing absorption in the 230-260 nm wavelength range and deteriorating light transmittance
Solution Approach 1:
The patent fundamentally changes the production approach from melting to chemical vapor deposition, and strictly controls impurity parameters by using high-purity starting materials and controlled processing conditions. The resulting quartz glass contains Fe and Cu at ≤50 ppb each, eliminating impurity-related absorption in the 230-260 nm range while maintaining excellent UV absorption through controlled titanium doping at 10-500 ppm
Solution Approach 2:
The patent extracts and removes impurity metals from the quartz glass system by employing chemical vapor deposition with high-purity reactants. This method inherently excludes contamination from crucibles and atmospheric sources that plague conventional melting, achieving ultra-low impurity levels (Fe, Cu ≤ 50 ppb) that eliminate harmful absorption bands
3Volume of moving object
If large-sized quartz glass tubes with outer diameter of 50 mm or more and wall thickness of 5 mm are produced using conventional methods, then the required size for increased lamp output is achieved, but the presence of air bubbles and foreign matter inclusions creates external appearance defects
Solution Approach 1:
The patent changes from conventional melting to chemical vapor deposition, enabling production of large-sized quartz glass (outer diameter ≥50 mm, wall thickness ≥5 mm) with uniformly distributed titanium (10-500 ppm) and controlled OH groups (10-350 ppm). This method produces defect-free large products by eliminating bubble and inclusion formation mechanisms inherent in melting processes
Solution Approach 2:
The patent performs preliminary purification by using chemical vapor deposition to build up the quartz glass structure layer by layer from high-purity vapor phase reactants. This preliminary formation process inherently excludes bubbles and inclusions before they can form, ensuring external appearance quality in large-sized products without requiring subsequent defect removal
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 quartz glass with excellent UV absorption, high purity, reduced strain, and minimal defects, enabling its use in large, thick-walled products for UV-blocking applications without significant reductions in transmittance.
Implementation Method 1
titanium-containing quartz glass having excellent UV absorption... for the purpose of absorbing UV radiation at wavelengths shorter than 254 nm or 365 nm
Implementation Method 2
a method for producing same comprises: a titanium doping step in which a porous quartz glass parent material produced by chemical vapor deposition is introduced
Implementation Method 3
the porous quartz glass parent material after the titanium doping step is subjected to a heating treatment under an oxygen-containing atmosphere
Data Source
AI summary
Provided is a titanium-containing quartz glass having excellent UV absorption. The quartz glass absorbs ultraviolet rays having a wavelength of 250 nm or less, ozone generation-related adverse effects on the human body, are prevented, a decrease in transmittance of the quartz glass in the range from near-ultraviolet to visible light due to being colored when irradiated with ultraviolet rays does not occur, absorption build-up or lamp burst-inducing deformation build-up, which is caused by a structural change in the quartz glass that occurs in the range of 200-300 nm when irradiated with ultraviolet rays, is suppressed, and a decrease in transmittance at intended wavelength ranges does not occur even when exposed to ultraviolet rays. The titanium-containing quartz glass having excellent UV absorption is colorless, wherein the average concentration of titanium is 10-500 ppm, the concentration of OH group is 10-350 ppm.