Combined Illumination and Imaging System for Thermal Processing
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Solution Overview
Problem
Current thermal processing systems face challenges in effectively illuminating and imaging substrates during thermal processing, particularly in achieving precise control over light distribution and thermal emission imaging.
Innovation Solution
A combined illumination and imaging system is developed, comprising a light source, optical train, and wavelength beam splitter, which focuses light into a defined geometrical pattern on the substrate and redirects thermal emission wavelengths for imaging, using monochromatic light sources, antireflective coatings, and polarization-rotation elements to manage light polarization and minimize backreflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a narrow elongated beam is used to illuminate the substrate during thermal processing, then the illumination precision is improved, but the system complexity increases due to the need for precise optical arrangement and translation mechanism control
Solution Approach 1:
The system separates illumination and imaging functions into distinct optical paths. The illumination system uses a laser source with cylindrical lens array to create a line pattern, while the imaging system uses a separate detector path with its own optics, allowing independent optimization of each function without increasing overall system complexity
Solution Approach 2:
The optical arrangement serves dual purposes: it shapes the illumination beam into a narrow elongated pattern for precise thermal processing, and simultaneously enables imaging of the substrate surface through the same optical path by capturing reflected or emitted light, thereby reducing the need for separate complex systems
2Productivity
If the illumination system operates continuously during substrate processing, then the productivity is improved, but the risk of light source damage from backreflection increases
Solution Approach 1:
An optical isolator is introduced as an intermediary component in the optical path between the laser source and the substrate. This device allows light to pass through in the forward direction while blocking any backreflected light from reaching the laser source, thus protecting the light source from damage during continuous operation
Solution Approach 2:
The system captures backreflected light that would otherwise damage the source and redirects it through the optical isolator to a beam dump or absorber. By converting the harmful backreflection into a controlled energy dissipation path, the system protects the light source while maintaining continuous operation capability
3Use of energy by moving object
If the optical elements are coated to minimize reflection at the illumination wavelength, then the illumination effectiveness is improved, but the imaging capability at thermal emission wavelengths is reduced
Solution Approach 1:
Different regions of the optical path are assigned different coating characteristics. Optical elements in the illumination path are coated for minimal reflection at the laser wavelength, while elements in the imaging path or with broader spectral response are optimized for thermal emission wavelengths, allowing each region to perform its specific function effectively
Solution Approach 2:
The system uses optical elements with coatings that have wavelength-dependent properties. By selecting materials and coating thicknesses that create different reflectivity/transmissivity characteristics at different wavelengths, the system achieves high illumination effectiveness at the laser wavelength while maintaining sufficient imaging capability at thermal emission wavelengths
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 system enhances the precision and effectiveness of thermal processing by providing a controlled illumination pattern and imaging of thermal emissions, improving substrate processing outcomes through optimized light management and reduced risk of light source damage.
Implementation Method 1
The wavelength beam splitter is adapted to transmit light of a first wavelength and to redirect light of a second wavelength
Implementation Method 2
The optical train has elements configured to focus light from the light source into a defined geometrical pattern on the surface
Implementation Method 3
the emission wavelength generated by thermal excitation of the surface by the focused geometrical pattern
Implementation Method 4
At least some of the optical elements may sometimes include an antireflective coating that is antireflective at the first wavelength and at the second wavelength
Implementation Method 5
The polarization-rotation element is adapted to change the specified linear polarization of light incident on the polarization-rotation element to a circular polarization
Implementation Method 6
The isolation beamsplitter is adapted to transmit light of a specified linear polarization and to redirect light not of the specified linear polarization from the optical path
Data Source
AI summary
An illumination system has a light source, an optical train, and a wavelength beam splitter. The optical train focuses light from the light source into a defined geometrical pattern on a surface. The wavelength beam splitter transmits light of a first wavelength and redirects light of a second wavelength. One of these wavelengths is included by the light from the light source, while the other is an emission wavelength generated by thermal excitation of the surface by the focused geometrical pattern.