FIELD: printing industry.
SUBSTANCE: invention relates to special types of printing. In the proposed sheet material, on each side of the plastic which is transparent to laser radiation, metal-coated diffraction gratings are placed opposite each other. These grates are simultaneously applied on the plastic layer by embossing and form on each of its opposite sides a recess of the diffraction grate which is deepened into the body of the plastic. Further, these grids are metallized, and one of them is coated with a layer of metallized foil. In proposed sheet material laser radiation pulses penetrating through metallized foil successively interact with two diffraction gratings, cause interference of beams reflected from diffraction gratings between them and metalized foil layer, as a result of which pairs of volumetric nanostructures are formed in channels formed by laser beams in metallized foil. When light material passes through sheet metal through channels in metallized foil, it is subjected to dispersion on non-demetallized sections of diffraction gratings and causes glow of pairs of volumetric nanostructures, making the luminous image visible in reflected light. In transmitted light, the same image is visible in form of transparent points owing to demetallized sections of diffraction gratings.
EFFECT: invention enables to obtain original images inside the disclosed sheet material for counterfeit protection of security papers and ID when exposed to laser radiation pulses.
3 cl, 2 dwg
