Polarimeter for Crystallographic Orientation Imaging
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Solution Overview
Problem
Current techniques for crystallographic orientation imaging, such as EBSD, are destructive, time-consuming, and limited by small image sizes, making it impractical to verify macrozones or microtexture regions in industrial metal parts, which are crucial for assessing failure probabilities.
Innovation Solution
A polarimeter with multiple independent tunable channels uses controlled electromagnetic radiation and polarization modulators to produce orientation images by mapping polarized reflectivity to crystal orientation, enabling faster, less destructive, and more accurate imaging of crystallographic structures across larger areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If EBSD is used for crystallographic orientation imaging, then complete crystallographic structure including orientation can be obtained, but the technique is destructive and requires careful sample preparation
Solution Approach 1:
The patent replaces the mechanical/electronic EBSD system with an optical polarimeter system that uses polarized light to measure crystallographic orientation. This substitution eliminates the need for vacuum chambers, electron beams, and destructive sample preparation while achieving comparable orientation measurement accuracy through optical polarization analysis
Solution Approach 2:
The invention changes the measurement parameter from electron diffraction patterns to polarized light reflectivity characteristics. By measuring how polarized light reflects from crystal surfaces at different orientations, the system derives crystallographic information without the harmful effects of electron beam exposure and sample destruction
2Measurement precision
If EBSD is used for crystallographic imaging, then crystal orientation can be revealed, but data acquisition times are long and increase linearly with the number of image pixels
Solution Approach 1:
The patent employs periodic modulation of polarizer and analyzer orientations to systematically采集 polarization data at multiple angles. This periodic scanning approach, combined with parallel pixel array detection, enables complete polarization state measurement at each pixel without sequential scanning, dramatically reducing acquisition time while maintaining orientation imaging precision
Solution Approach 2:
The invention adds the polarization state dimension to the spatial imaging measurement. By measuring not just intensity but the full polarization state (amplitude and orientation) of reflected light, the system extracts crystal orientation information from polarization characteristics rather than relying on time-consuming diffraction pattern analysis
3Measurement precision
If EBSD is used for crystallographic orientation imaging, then grain sizes and shapes can be measured, but the field-of-view is limited to small areas that do not exceed ten millimeters on a side
Solution Approach 1:
The patent creates a multi-functional optical system that can simultaneously measure crystal orientation, grain size, and macrozone characteristics across large areas. The polarimeter uses standard optical components and visible light to achieve universal applicability to various crystal structures and orientations without the geometric limitations of electron beam systems
Solution Approach 2:
The invention transitions from the limited electron beam interaction volume to optical wavelengths that can traverse and reflect from much larger sample areas. By using polarized light instead of electron beams, the system achieves macroscopic field-of-view capability while maintaining microscopic resolution through optical focusing and polarization analysis
4Ease of operation
If conventional polarized-light microscopy is used, then grain sizes and shapes can be imaged, but accurate crystal orientation within grains cannot be provided
Solution Approach 1:
The patent introduces polarization state analysis as an intermediary measurement between simple light intensity detection and complex diffraction pattern analysis. By measuring the amplitude and orientation of polarized light reflected from crystal surfaces, the system derives crystal orientation information with accuracy comparable to EBSD while maintaining the operational simplicity of optical microscopy
Solution Approach 2:
The invention changes the measured parameter from simple light intensity to the full polarization state (amplitude and orientation) of reflected light. This parameter change enables extraction of crystal orientation information that was previously inaccessible to conventional polarized-light microscopy, achieving accurate orientation measurement while preserving ease of operation
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 allows for efficient and accurate crystallographic orientation imaging of industrial parts, overcoming the limitations of existing methods by providing unique and efficient mapping of crystal orientations with fewer images, accommodating diverse physical effects, and enabling the application of macrozone models to larger areas.
Implementation Method 1
A first polarization modulator is positioned in the path preceding the sample and the first polarization modulator is configured to switch serially among multiple independent settings
Implementation Method 2
An electromagnetic-radiation collector is positioned to direct electromagnetic radiation reflected from or transmitted by the sample to a second polarization modulator
Implementation Method 3
The second polarization modulator is configured to switch serially among multiple independent settings
Implementation Method 4
The imaging detector is positioned to receive electromagnetic radiation from the sample transmitted through the second polarization modulator, wherein the imaging detector comprises pixels and produces a set of images
Implementation Method 5
the processor is configured to execute a classification algorithm stored in the memory that maps the set of spatially registered images to one or more material orientation images by mapping a set of values for each detector pixel corresponding to the set of spatially registered images to a value of material orientation at each pixel coordinate using a model
Data Source
AI summary
A polarimeter and a method of analyzing and imaging microstructural material orientation of a polished reflective sample are disclosed. The polarimeter, which is a partial Mueller-matrix polarimeter (pMMP), accesses multiple independent polarization channels by employing two independent polarization modulators configured to switch serially among multiple independent settings, wherein the combination of the settings of the first and second polarization modulators defines an independent polarization channel, and wherein an imaging detector produces a set of polarization images that are synchronized with the channels formed by the polarization modulators; and wherein a processor connected with a memory executes a classification algorithm stored in the memory that maps the set of polarization images to one or more material orientation images by mapping the set of values for each detector pixel corresponding to the set of polarization images to a value of material orientation at each pixel coordinate using a model. The invention can thereby create material microstructural orientation images of diverse anisotropic materials, for instance polymer domains, fiber bundles or plys, and crystalline grains.