Optical Fibre Diameter Analyser Calibration for Bimodal Cashmere Histogram Profiling
Calibrate OFDA optical thresholds and medullated density adjustments under IWTO-47 to accurately deconvolve bimodal cashmere histograms and verify coarse hair mass.
Diffraction Halo
Optical Pattern
Circular light patterns generated by the scattering of coherent light around individual fiber profiles provide the basis for laser-based diameter measurement. Observing the diffraction halo allows optical instruments to calculate average fiber thickness in wool samples. This automated method replaces manual projection microscope scanning in high-throughput testing laboratories and accelerates the commercial certification of raw fiber lots.
Measurement Mechanism
Light beams from a helium-neon laser scatter at angles inversely proportional to the width of the fibers they encounter. The resulting diffraction halo presents alternating light and dark bands on a sensor array. Processing software interprets these band spacings to generate a complete micron distribution profile for the scanned sample.
System Configuration
Proper alignment of the lens array ensures the light pattern remains focused on the sensor surface. Dust particles or oil residues on the fiber slide can distort the diffraction halo, leading to false thickness readings. Cleanliness protocols are mandatory during sample preparation to maintain instrument calibration.
Analytical Boundary
Highly irregular fiber cross-sections can disrupt the symmetry of the projected rings. Although the diffraction halo method works for round fibers like wool, it loses accuracy when applied to flat or highly hollow synthetic structures. Alternative optical methods are required for non-circular fiber geometries.