Measuring birefringence of filament yarns

摘要

A process is for the automatic and contact-free measuring of the birefringence of filament yarns in small spaces and uses a laser light source to determine thread difference and diameter at the same time. The filaments (18) to be measured are subjected to laser radiation via a polarisation-maintaining photo-conductive cable (4). The directly bent light is transmitted via a miniature objective (6) to an optic cable (7) and led on from there to a computer through a CCD line (8) as a minimum distance from dia. determination.