Synthetic Quartz Glass Flame Profile for Higher SiO2 Deposition

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Solution Overview

Problem

Existing processes for producing synthetic quartz glass suffer from low deposition efficiency of silicon-containing starting materials, leading to high manufacturing costs.

Innovation Solution

A process involving a targetless synthesis flame with a specific luminous intensity ratio and controlled air number is used to deposit SiO2 particles, optimizing the deposition efficiency by maintaining a laminar flame shape and increasing residence time on the deposition surface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If conventional deposition processes are used, then deposition efficiency is insufficient, but manufacturing costs increase

Engineering Contradiction:

Improvedeposition efficiencyVSAvoidmanufacturing costs

Core Design Contradiction:

ProductivityVSEase of manufacture

Solution Approach 1:

The patent applies parameter changes by optimizing the flame characteristics (luminous intensity ratio FWHM_vert/FWHM_hori > 10), oxygen supply (air number ≤ 1.0), and burner geometry to achieve superior deposition efficiency. These parameter optimizations enable complete silicon conversion to SiO2 while maintaining cost-effective manufacturing processes.

Inventive Principle:

Principle #35Parameter changes

2Productivity

If silicon-containing starting material is not fully converted, then deposition efficiency is low, but material loss increases

Engineering Contradiction:

Improvedeposition efficiencyVSAvoidsilicon material loss

Core Design Contradiction:

ProductivityVSLoss of substance

Solution Approach 1:

The patent employs strong oxidation conditions by supplying oxygen at an air number ≤ 1.0 (sub-stoichiometric or stoichiometric conditions) in the flame, ensuring complete conversion of silicon from the organosilicon starting compound to SiO2. This accelerated oxidation eliminates unconverted silicon material, maximizing deposition efficiency and minimizing material loss.

Inventive Principle:

Principle #38Strong oxidants (Accelerated oxidation)

3Productivity

If flame shape is not optimized, then residence time is insufficient, but deposition efficiency decreases

Engineering Contradiction:

Improvedeposition efficiencyVSAvoidresidence time

Core Design Contradiction:

ProductivityVSDuration of action of moving object

Solution Approach 1:

The patent utilizes asymmetric flame shape characteristics by maintaining a luminous intensity ratio FWHM_vert/FWHM_hori > 10, creating an elongated vertical flame profile. This asymmetric geometry increases the residence time of SiO2 particles in the deposition zone, allowing complete conversion and deposition while improving overall deposition efficiency.

Inventive Principle:

Principle #4Asymmetry

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 process achieves improved deposition efficiency, resulting in reduced manufacturing costs for synthetic fused silica by enhancing the quotient of deposited SiO2 weight to the maximum theoretical SiO2 amount.

Implementation Method 1

the feedstock vapor is burned in a flame in the presence of oxygen and is converted to SiO2 soot particles by oxidation

Methodology Applied

Scientific EffectOxidation: Oxidation

Implementation Method 2

converted to SiO2 soot particles by oxidation and/or by hydrolysis

Methodology Applied

Scientific EffectHydrolysis: Hydrolysis

Implementation Method 3

depositing the SiO2 soot particles resulting from process step (2) on a deposition surface to form a soot body

Methodology Applied

Scientific EffectDeposition: Deposition (physical)

Implementation Method 4

drying and vitrifying the soot body resulting from process step (3) to form synthetic fused silica

Methodology Applied

Scientific EffectVitrification: Vitrification

Data Source

PatentEP4015469B1Method for the manufacture of synthetic quartz glass

Publication Date: 2025.12.03 HERAEUS QUARZGLAS GMBH & CO KG

Figure 1

AI summary

Described is a method of producing synthetic fused silica in which the synthetic flame used in the method has a ratio of the Full Width at Half Maximum (FWHMvert) vertical luminous intensity to the Full Width at Half Maximum (FWHMhori) horizontal luminous intensity greater than 10 in a targetless state, the luminous intensities being measured in candela/mm2.