Silicon Carbide Mirror Manufacturing with Thermal Spray Silicon Coating

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Solution Overview

Problem

Traditional Silicon Carbide scanning or optical mirror manufacturing is hindered by high costs and time consumption due to the material's extreme mechanical hardness, making it difficult to achieve industrially required flatness and surface quality, which limits reflective performance and requires multiple polishing stages and uncertain optical coating compatibility.

Innovation Solution

The method involves isostatic pressing and sintering of Silicon Carbide powder using an engineered stamp, followed by bonding an alternative material like Silicon, and using thermal spray processes to deposit and polish this layer for achieving high-quality surface finishes, reducing manufacturing time and cost, and enhancing surface roughness and coating compatibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If Silicon Carbide powder is pre-pressed and sintered to manufacture scanning or optical mirrors, then the mirrors achieve the required structural strength and form, but the manufacturing process becomes significantly expensive and time consuming due to the material's extreme mechanical hardness

Engineering Contradiction:
Improvesurface flatnessVSAvoidmanufacturing time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The invention applies preliminary action by pre-forming the mirror substrate using isostatic pressing and sintering to achieve the required structural strength and basic form before applying the optical surface layer. This separates the structural formation process from the optical surface finishing process, allowing each to be optimized independently.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention uses composite materials by combining Silicon Carbide substrate with a deposited layer of Silicon or alternative material. The Silicon Carbide provides structural strength and form, while the deposited Silicon layer provides the polishable optical surface, creating a composite structure that overcomes the limitations of pure Silicon Carbide.

Inventive Principle:
Principle #40Composite materials

2Manufacturing precision

If Silicon Carbide is directly polished to achieve industrially required flatness, then the surface quality improves, but the process becomes significantly expensive and difficult due to the material's extreme mechanical hardness

Engineering Contradiction:
Improvesurface flatnessVSAvoidpolishing difficulty
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The invention introduces an intermediary material layer (Silicon or alternative material) deposited on the Silicon Carbide substrate. This intermediary layer serves as a mediator that can be easily polished to achieve the required optical flatness, while the underlying Silicon Carbide substrate maintains its structural strength without needing to be directly polished.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The deposited Silicon layer acts as a disposable sacrificial layer that is easier and cheaper to polish than the Silicon Carbide substrate. This layer can be removed or polished away after serving its purpose of enabling achievable surface flatness, reducing the overall manufacturing cost and difficulty.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Manufacturing precision

If multiple lapping and polishing stages are used on Silicon Carbide to achieve required surface quality, then the surface flatness improves, but the polishing material wear and consumption increases significantly along with greater polishing times

Engineering Contradiction:
Improvesurface flatnessVSAvoidpolishing material wear
Core Design Contradiction:
Manufacturing precisionVSLoss of substance

Solution Approach 1:

The deposited Silicon layer serves as an intermediary that is softer and more easily polished than Silicon Carbide. This intermediary layer absorbs the polishing action, reducing wear on polishing materials while still achieving the required surface flatness through standard polishing procedures.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Manufacturing precision

If Silicon Carbide mirrors are polished to achieve surface quality of Ra < 3 micrometers, then the reflective performance improves, but the surface structure limitations may still restrict optical coating compatibility and performance

Engineering Contradiction:
Improvesurface roughnessVSAvoidoptical coating compatibility
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The composite structure of Silicon Carbide substrate with deposited Silicon layer provides both the required surface roughness (Ra < 3 micrometers) for reflective performance and a surface composition (Silicon) that is known to be compatible with optical coatings, ensuring reliable coating adhesion and performance.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The invention changes the surface material parameter from pure Silicon Carbide to a deposited Silicon or alternative material layer. This parameter change maintains the required surface roughness for optical performance while improving the chemical compatibility with optical coatings, as Silicon surfaces are well-established substrates for optical coating deposition.

Inventive Principle:
Principle #35Parameter changes

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 manufacturing time and cost, improves surface quality to Ra < 3 micrometers, and ensures compatibility with optical coatings, enhancing the reflective performance of Silicon Carbide mirrors by using known materials and processes.

Implementation Method 1

using thermal spray processes to deposit and polish this layer

Methodology Applied
Scientific EffectThermal spray: Plasma Spray

Implementation Method 2

isostatic pressing and sintering of Silicon Carbide powder

Methodology Applied
Scientific EffectIsostatic pressing: Hot Isostatic Pressing

Implementation Method 3

isostatic pressing and sintering of Silicon Carbide powder

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP2191321B1Method of manufacturing and processing silicon carbide scanning and optical mirrors
Publication Date: 2012.12.19 MERSEN DEUTLAND HLDG
  • EP2191321B1 patent drawingFigure 1
  • EP2191321B1 patent drawingFigure 2~3
  • EP2191321B1 patent drawingFigure 4~5

AI summary

The invention relates to a method of Silicon Carbide scanning or optical mirror production. In order to reduce the costs for manufacturing a scanning or optical mirror, according to the present invention, Silicon Carbide powder is pressed or stamped or isostatically pressed using an engineered stamp or tool to form the shape and structure of a scanning or optical mirror which is then in this embodiment sintered to provide a surface that will become the face surface of said scanning or optical mirror that is then coated or bonded with a suitably thick layer of in this embodiment Silicon material deposited by a thermal spray process onto said face surface of said scanning or optical mirror that is then polished to achieve the desired surface quality and/or roughness and/or flatness and then optical coated using coating technologies and materials to coat said face surface that will then become the reflective surface with suitable high reflective optical coatings specific to the wavelength or wavelengths that the finished Silicon Carbide scanning or optical mirrors will be used to reflect in final application/s.