PROTECTIVE ELEMENT WITH TWO-DIMENSIONAL PERIODIC COLOUR-FILTERING GRATING Russian patent published in 2017 - IPC G02B5/20 G02F1/01 

FIELD: safety.

SUBSTANCE: protective element for valuable document, which includes a colour-filtering grating. Grating has connected highly refractive metal base layer (3), which defines plane of grating. Above base layer (3) there are protrusions with highly refractive, metal surface elements (5), which form two-dimensional regular pattern (6) and extend in parallel to plane of grating and are spaced apart from base layer (3) by intermediate dielectric (4) at a distance which is greater than thickness of base layer (3) and surface elements (5). Regular pattern (6) in at least two directions, extending parallel to plane of grating, has periodicity (p₁, p₂) from 100 nm to 800 nm, preferably from 200 nm to 500 nm.

EFFECT: technical result consists in creation of protective element with two-dimensional periodic colour-filtering grating, which, on one hand, has good colour-filtering properties, and on other hand, simple method of printing.

12 cl, 15 dwg, 1 tbl