Hyperspectral Crystallinity Mapping of Polymer Coatings
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Solution Overview
Problem
Current methods for measuring the degree of crystallinity of polymer coatings on metallic substrates are hindered by factors like humidity, substrate chattering, and light exposure, which degrade the coating and limit precision, especially when attempting to map crystallinity across the full width of the coating.
Innovation Solution
A method using a polychromatic light source in the infrared domain and a hyperspectral camera to measure light intensity at specific wavelengths, both impacted and unaffected by crystallinity, allowing for precise determination and mapping of crystallinity across the full width of the coating without degrading it, using a ratio of absorbances to estimate crystallinity and convert to a degree of crystallinity map.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Raman spectroscopy is used to measure crystallinity degree, then non-destructive measurement is achieved, but measurement precision deteriorates due to lighting source heating and degradation of the coating
Solution Approach 1:
The patent changes the measurement parameter from Raman spectroscopy (which uses high-energy light that degrades the coating) to infrared reflectance spectroscopy. This parameter change allows measurement of crystallinity through molecular vibrations in the infrared domain without causing photo-degradation, thus maintaining both non-destructive measurement and high precision
Solution Approach 2:
The patent introduces an intermediary approach by measuring the reflectance of infrared light instead of directly measuring Raman scattering. This intermediary method avoids the harmful heating effect while still providing information about the crystalline structure through characteristic infrared absorption bands
2Reliability
If Raman spectroscopy is used to measure crystallinity degree, then non-destructive measurement is achieved, but measurement precision deteriorates due to environmental factors like humidity and substrate chattering
Solution Approach 1:
The patent uses feedback by measuring the reflectance at multiple wavelengths and using ratio calculations to compensate for environmental variations. The system continuously monitors and adjusts measurements to account for humidity and substrate movement effects, maintaining precision under varying conditions
3Productivity
If single spot measurement is used, then measurement time is reduced, but measurement coverage deteriorates as only a single spot along the substrate coating width is determined
Solution Approach 1:
The patent transitions from single-point measurement to full-width area measurement by using a line-of-sight infrared reflectance measurement approach. This dimensional change allows simultaneous measurement across the entire coating width while maintaining fast measurement speed, effectively adding spatial coverage without sacrificing productivity
4Measurement precision
If infrared lighting is used to illuminate the coating, then measurement of crystallinity is enabled, but coating degradation occurs favouring formation of crystalline phase
Solution Approach 1:
The patent changes the lighting parameter from visible light (used in Raman spectroscopy) to infrared light. This parameter change enables measurement of crystallinity through infrared reflectance without causing photo-degradation, as infrared photons have lower energy and do not induce chemical bond breaking that would alter the coating composition
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
Enables precise, non-destructive measurement of crystallinity across the full width of polymer coatings on metallic substrates, unaffected by operating conditions like humidity and lighting, with improved resolution compared to existing techniques.
Implementation Method 1
lighting a transversal area of said polymer coating (1) encompassing its full width W, with a polychromatic light including wavelengths in the infrared domain
Implementation Method 2
measuring with at least one hyperspectral camera (3), the light intensity S impacted,λ α at a predetermined wavelength λα impacted by the degree of crystallinity... after reflection on said moving metallic substrate (2)
Implementation Method 3
measuring with at least one hyperspectral camera (3), the light intensity S impacted,λ α at a predetermined wavelength λα impacted by the degree of crystallinity... determining at least an impacted absorbance A imp , using said light intensity S impacted,λ α
Data Source
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AI summary
The present invention relates to a method and a measuring equipment of the degree of crystallinity of a polymer coating on a metallic substrate using a hyperspectral camera as well as representing or mapping said degree of crystallinity. An equipment for online measurement of crystallinity of polymers, according to the present invention comprising at least one hyperspectral camera, at least one lighting source, a polymer layer deposited on a substrate and means to convey said substrate, the lighting source and the hyperspectral camera being set-up in specular reflection towards said polymer layer.