DIFFRACTIVE PROCEDURE DETERMINING NUMBER OF MAIN CHARACTERISTICS OF CLOTH AND CLOTH-LIKE MATERIALS Russian patent published in 2003 - IPC

FIELD: test of geometric characteristics of cloths and cloth-like materials. SUBSTANCE: diffractive procedure determining number of main characteristics of cloths and cloth- like materials includes fixing of specimen, illumination of specimen with parallel cophasal coherent light beam of laser perpendicular to cloth surface and observation of diffraction pattern on screen positioned behind tested specimen, subsequent analysis of diffraction pattern with measurement of angle ϕ contained between horizontal and vertical axes which is used to evaluate geometric properties of tested specimen. Analysis of diffraction patterns of cloths and cloth-like materials manufactured by process of weaving from fibers or fiber-like materials is realized with additional measurement of average distances between horizontal and vertical axes by which width d and length D of repeat are found by formulas where λ is length of wave of light source; R is distance from specimen to observation screen, with additional isolation of central horizontal and vertical axes passing through center of illumination spot of laser light on specimen with subsequent measurement of amplitudes of diffraction maxima located along central axes by which judgment on widths a₁,.....a_m, of pores included in repeat by width and on height b₁,.....b_n, of pores included in repeat by height is made by formulas, diameters of fibers and fiber-like materials located in direction a of production of cloth and cloth-like materials and in direction b perpendicular to production direction are evaluated by measured values of width a₁,.....a_m, of pores included in repeat by width and by measured values of height b₁,.....b_n, of pores included in repeat by height and by values d and D with the help of formulas. Parting of fibers and fiber-like materials along direction perpendicular to direction of production ΔD is estimated by decrease of value of average distance between adjacent vertical rows of diffraction maxima. Parting of fibers and fiber-like materials along direction of production Δd is judged by decrease of value of average distance between adjacent horizontal rows of diffraction maxima. Local thickening of fibers and fiber-like materials placed in direction of production and in direction perpendicular to it and disturbance in weaving are detected by change of values of intensity of first two maxima lying correspondingly on central horizontal and vertical rows. Skewness of cloth and cloth-like materials in direction perpendicular to direction of production is evaluated by measured value of angle ϕ of deviation of rows of diffraction maxima from vertical, skewness of cloth and cloth-like materials along direction of production is evaluated by angle ψ. of deviation of rows of diffraction maxima from horizontal. EFFECT: enhanced accuracy of measurement of geometric characteristics of cloths and cloth-like materials. 2 cl, 6 dwg