SHEET MATERIAL AND SHEET MATERIAL AUTHENTICITY CHECKING METHOD Russian patent published in 2003 - IPC

FIELD: sheet material used for manufacture of banknotes, securities, credit cards, labels or package for goods. SUBSTANCE: sheet material comprises authenticity agent made in the form of fibers of amorphous magnetically soft material, said fiber being distributed in sheet material mass. Length, width, thickness or diameter of amorphous magnetically soft material or magnetic moment values are selected in accordance with predetermined distribution function values. Length of fibers is within the range of 0.5-32 mm, width is within the range of 30-400 microns, thickness is within the range of 0.3-30 microns, and diameter is within the range of 3-400 microns. Fibers are uniformly distributed in material mass at density of 20-20х10³ g/t. Fibers are manufactured from magnetically soft magnetostrictive alloy. Fibers are manufactured from amorphous magnetically soft material of Fe-Co-Ni, Fe-Ni-B, Co-Mn-Si-B systems. Method involves moving sheet material having authenticity agent through magnetic field; registering signal response amplitude from each fiber of amorphous magnetically soft material; evaluating sheet material authenticity extent by determining distribution function of signal response amplitude. Sheet material authenticity is evaluated by shape of curve of integral and/or differential function of signal response amplitude distribution. EFFECT: increased efficiency by eliminating possibility of counterfeit, simplified authenticity proving and reduced production costs. 9 cl, 6 dwg, 2 tbl