OPTICALLY VARIABLE SECURITY THREADS AND STRIPS Russian patent published in 2017 - IPC D21H21/42 G09F3/02 

FIELD: physics.

SUBSTANCE: security thread or strip comprises a) an optically variable layer giving a different colour perception at different viewing angles and made of an optically variable composition comprising from 2 to 40 wt % of optically variable pigments. The mentioned optically variable layer comprises one or more gaps in the form of signs or consists of signs made of an optically variable composition. Weight percentages are indicated based on the total weight of the optically variable composition; b) a permanent colour layer having a colour coinciding with the colour perception of the optically variable layer at the viewing angle and made of a permanent colour composition containing from 1 to 20 wt % of one or more colourants and/or from 0.1 to 45 wt % of inorganic pigments, organic pigments or mixtures thereof. The mentioned layer of permanent colour either contains one or more gaps in the form of signs, or consists of signs made of a permanent colour composition, wherein the weight percentages are indicated based on the total weight of the permanent colour composition; c) a holographic metal layer and d) a substrate; i) the holographic metal layer faces the substrate, ii) the permanent colour layer and the optically variable layer are disposed over the holographic metal layer, and iii) the permanent colour layer and/or the optically variable layer are facing/is facing the environment, and wherein the optically variable layer, the permanent colour layer and the holographic metal layer are at least partially co-visible from the side of the security thread or strip containing the optically variable layer and/or the permanent colour layer.

EFFECT: security threads or strips demonstrate a highly dynamic visual effect of motion when tilted.

15 cl, 8 dwg