OPTICAL METHOD OF CONTROLLING THREAD TWISTING Russian patent published in 2012 - IPC G01N21/21 

FIELD: physics.

SUBSTANCE: analysed thread is illuminated with plane-polarised light whose polarisation plane is turned about the axis of the light beam with frequency ω, and the light scattering anisotropy coefficient is calculated using the formula where is the amplitude of the alternating component of light flux which varies with frequency 2ω and is scattered back in a solid angle directed in a plane which coincides with the direction of the thread; is the amplitude of variable component of light flux which varies with the same frequency and is scattered in the same solid angle and at the same angle to the direction of incidence of light, but lying in a perpendicular plane, and the twisting value of the thread is determined from the known relationship between the anisotropy coefficient and the twisting value.

EFFECT: high sensitivity owing to selection from light flux from the illuminated part of the analysed thread and subsequent measurement of only its polarised part.

3 dwg