OPTICAL PROTECTIVE DEVICE AND METHOD FOR ITS MANUFACTURING Russian patent published in 2023 - IPC B42D25/328 

FIELD: computer technology.

SUBSTANCE: invention relates to visually observable and/or machine-readable security elements based on multicolour relief-carrying holograms exhibiting diffraction-interference effects in combination with metallized elements observed “peek-a-boo”. Claimed multilayer protective device with a topological spatial areaψ (x, y) comprises security features that provide visually visible and invisible, but machine-readable security information for identifying authenticity and is placed on a temporary substrate in the form of a carrier film with a separating layer and two spatially aligned optical elements with sub-regions ζ (x, y) and χ (x,y) within the general area ψ (x, y). In this case, the optical element ζ (x, y) is made in the form of a image-based demetallized flat and smooth surface of a thermoplastic linear polymer layer, uniform in thickness, transparent to the light, deposited over the entire area ψ (x, y) of a security device, whereas another metallized holographic relief-structured optical element χ (x, y), spatially aligned with the optical element ζ (x, y) is located on the rest of the surface of the same thermoplastic layer within the region ψ (x, y) of the protective device, but on its holographic relief-structured section (sub-region) with a metal layer deposited on top of it, whereas the optical element itself χ (x, y) includes at least several metallized subsections, where each of the specified subsections of the optical element χ (x, y) has a metal surface consisting of two different non-ferrous metals 1 and 2, differing in the spectra of reflection and transmission, and spaced apart within one specified subsection. The thickness of the non-ferrous metals of these metallized layers of the optical element χ (x, y) is in the range from 10 to 100 nm, and the high-precision spatial alignment of the metallized-demetallized subregions ζ (x, y) and χ (x, y) located in a single micro-demetallized stencil ψ (x, y) of the protective device is carried out with an accuracy of about 5 μm. Spatial alignment of fragments of the same image made on layers of different metals was carried out without mutual overlap, transverse shifts and breaks with an alignment accuracy within 2-5 μm.

EFFECT: increased registration accuracy up to about 5 µm and increased security features for both visually readable and machine-readable verification of the security element, in particular on its both sides.

5 cl, 3 dwg