Quartz Glass Optical Component Drawing with Homogeneous Handle

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Solution Overview

Problem

Conventional methods for drawing quartz glass optical components often result in waveguide distortions and waste due to non-uniform temperature and viscosity distribution, leading to poor clad-to-core ratios and increased core eccentricity, as the glass handle and preform have different thermal properties and radial geometries, causing the outer cladding glass to flow faster than the inner core glass.

Innovation Solution

A system and method where the glass handle and glass body have matching square cut ends with a uniform radial geometry, ensuring a uniform temperature and viscosity distribution, allowing the core and cladding glasses to flow at equal rates, maintaining the necessary clad-to-core ratio and reducing distortions by using a glass handle with an outer diameter between 50% and 110% of the glass body's diameter, and heating to temperatures between 500°C to 2300°C.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the glass handle is made with smaller outer diameter and inferior quality glass to reduce costs, then manufacturing cost is reduced, but waveguide distortions occur and manufacturing precision deteriorates

Engineering Contradiction:
Improvemanufacturing costVSAvoidwaveguide distortion
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The glass handle is made with the same outer diameter as the glass body and uses the same quality glass material. This homogeneity ensures uniform thermal properties and radial geometry throughout the entire structure, preventing waveguide distortions while maintaining manufacturing precision.

Inventive Principle:
Principle #33Homogeneity

2Manufacturing precision

If the draw is terminated early to avoid drawing distorted end glass, then waveguide quality is maintained, but glass waste increases and productivity decreases

Engineering Contradiction:
Improvewaveguide qualityVSAvoidglass utilization
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

By making the glass handle identical in diameter and material quality to the glass body, the entire length of the coaxial arrangement can be drawn without quality degradation. This eliminates the need to terminate the draw early, maximizing glass utilization and productivity while maintaining waveguide quality throughout.

Inventive Principle:
Principle #33Homogeneity

3Ease of manufacture

If the glass handle has different thermal properties and radial geometry than the glass body, then ease of manufacture is improved, but temperature and viscosity distribution uniformity deteriorates

Engineering Contradiction:
Improveglass handle fabricationVSAvoidtemperature distribution uniformity
Core Design Contradiction:
Ease of manufactureVSStability of the object's composition

Solution Approach 1:

The glass handle is designed with identical outer diameter and material composition to the glass body, creating uniform radial geometry and thermal properties throughout. This homogeneity ensures even temperature and viscosity distribution during the drawing process, preventing distortion while maintaining manufacturability.

Inventive Principle:
Principle #33Homogeneity

4Productivity

If the outer cladding glass flows faster than the inner core glass due to non-uniform viscosity, then drawing speed is increased, but clad-to-core ratio precision deteriorates

Engineering Contradiction:
Improvedrawing speedVSAvoidclad-to-core ratio
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

By ensuring the glass handle has the same diameter and material properties as the glass body, uniform viscosity is maintained throughout the structure during heating. This prevents differential flow rates between outer cladding and inner core glass, maintaining precise clad-to-core ratios while allowing efficient drawing speeds.

Inventive Principle:
Principle #33Homogeneity

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 significantly reduces waveguide distortions, increases yield to 95% or more, and minimizes scrap rates, ensuring the produced optical fibers have acceptable clad-to-core ratios, mode field diameters, and core eccentricity within required tolerances.

Implementation Method 1

the glass handle and glass body have matching square cut ends with a uniform radial geometry, ensuring a uniform temperature and viscosity distribution, allowing the core and cladding glasses to flow at equal rates, maintaining the necessary clad-to-core ratio and reducing distortions by using a glass handle with an outer diameter between 50% and 110% of the glass body's diameter, and heating to temperatures between 500°C to 2300°C

Methodology Applied
Scientific EffectThermal heating: Heating

Implementation Method 2

the heated inner and central portion of the glass that contains the fiber core flows axially downwardly (e.g., by gravity or externally applied drawing or holding forces) at a different rate than the heated outer cladding glass due to radially non-uniform temperature and viscosity distribution within the glass body

Methodology Applied
Scientific EffectGravitational flow: Gravitation

Implementation Method 3

This length is often comparable to the length of the heat zone of the draw furnace (e.g., typically 10 to 20 cm) and typically similar to the diameter of the glass component being drawn due to the desirable efficiency of radiative heat exchange or transfer between the glass component and the draw furnace

Methodology Applied
Scientific EffectRadiative heat transfer: Thermal Radiation

Data Source

PatentEP3180293B1Method for forming a quartz glass optical component and system
Publication Date: 2021.01.20 HERAEUS QUARTZ NORTH AMERICA LLC
  • EP3180293B1 patent drawingFigure 1
  • EP3180293B1 patent drawingFigure 2A~2B
  • EP3180293B1 patent drawingFigure 3A~3B

AI summary

A method of producing a quartz glass optical component is provided. The method includes providing a cylindrical quartz glass body made of core rod glass and cladding glass. The quartz glass body has a square cut first end having a first outer diameter. The method further includes providing a glass handle having a first end and an opposing square cut second end having a second outer diameter which is between 50% and 110% of the first outer diameter; attaching the square cut end of the glass handle to that of the quartz glass body; and using the glass handle to guide the quartz glass body through a draw furnace. A distortion in a clad-to- core ratio proximate the interface of the cylindrical quartz glass body and the glass handle is less than 5%.