The invention relates to the use of one or more compounds of the 4-bora-3a,4a-diaza-s-indacene family for the preparation of a security element for a product, in particular a document, said security element comprising a polymer and said compound(s) being incorporated in said polymer, and to a method for ensuring the security of a product, in particular that of a document.

The invention relates to the use of one or more compounds of the 4-bora-3a,4a-diaza-s-indacene family for the preparation of a security element for a product, in particular a document, said security element comprising a polymer and said compound(s) being incorporated in said polymer, and to a method for ensuring the security of a product, in particular that of a document.

A secure item including a first optical structure and a second optical structure, or an assembly comprising a secure item and another object. The first optical structure including a plurality of blocks and being one of a revealing screen and a combined image. The second optical structure being the other one. Each of the combined image blocks being made up of a plurality of interlaced images. The combined image or each combined image block including a periodic alternation of interlaced image elements. The elements of the interlaced images of a single interlaced image being the same color, but a different color from that of the other interlaced images. At least two blocks of the first optical structure each allowing the observation of a revealed image in each block of a first optical structure, showing different proportions of the interlaced images.

Improving the adhesion of a laminate on a plastic card where the laminate overlays a print receptor layer. The size of the laminate is made larger than the print receptor layer so that at least a portion of the perimeter edge of the laminate extends beyond the perimeter edge of the print receptor layer so that the portion of the perimeter edge is adhered or otherwise bonded directly to the surface of the plastic identification document substrate or to other material of or on the plastic identification document substrate other than the print receptor layer. This increases the difficulty in picking the edges of the laminate loose and peeling the laminate from the print receptor layer and from the plastic identification document substrate.

Improving the adhesion of a laminate on a plastic card where the laminate overlays a print receptor layer. The size of the laminate is made larger than the print receptor layer so that at least a portion of the perimeter edge of the laminate extends beyond the perimeter edge of the print receptor layer so that the portion of the perimeter edge is adhered or otherwise bonded directly to the surface of the plastic identification document substrate or to other material of or on the plastic identification document substrate other than the print receptor layer. This increases the difficulty in picking the edges of the laminate loose and peeling the laminate from the print receptor layer and from the plastic identification document substrate.

A security element comprising a first and a second pattern formed in or on a substrate is described, the first pattern (105; 205) being formed by discrete elements (105a-105g; 205a-205c) of a first material that are distributed over a first region (101) of the substrate (100; 200), the second pattern (106; 206) being formed by discrete elements (106a-106i; 206a-206c) of a second material that are distributed over a second region (102) of the substrate (100; 200), said second material being different from said first material, said first and second regions of the substrate overlapping, wherein the discrete elements of at least one of the first and second patterns are distributed randomly, a part of the discrete elements of the first pattern (105; 205) overlap with a part of the discrete elements of said second pattern (106; 206), and the security element is defined by the first pattern (105; 205), the second pattern (106; 206) and a third pattern (107; 207) associated with the overlap of some or all of the discrete elements of said first and second patterns.

Forming a 3D image using a lenticular structure includes a carrier layer having an arrangement of color sub-pixels and a lenticular array comprising convergent lenses facing the sub-pixels. A method includes performing visual inspection of the lenticular structure, during which sub-pixels viewable through the lenses are detected for a plurality of viewing directions; determining, based on the color of the sub-pixels detected for each viewing direction, grayscale levels required to reveal M images viewable through the lenticular array in the M viewing directions, respectively; and customizing the sub-pixel arrangement, during which the grayscale levels are engraved facing the sub-pixels in the carrier layer by focus of laser radiation through the lenses.

A security feature is presented for a security or value document. The security feature comprises a zinc sulfide luminophore in the form of particles. The zinc sulfide luminophore has the general chemical formula ZnS:Cu.sub.x, M.sub.y, X.sub.z; here, M represents one or more elements from a group comprising the chemical elements Co, In and Ni; X represents one or more elements from a group comprising the halides F, Cl, Br and I; and the following applies: 0<x<0.002 and 0::; y<0.00015 and 0::; z<0.00050. The particles each have cubic phase portions and hexagonal phase portions. When excited by an electrical field, the zinc sulfide luminophore emits a first radiation in the range of the light spectrum between 580 nm and 780 nm. When excited by heating the luminophore to a temperature between 100? C. and 150? C., the zinc sulfide luminophore emits a second radiation in the light spectrum.

A security feature is presented for a security or value document. The security feature comprises a zinc sulfide luminophore in the form of particles. The zinc sulfide luminophore has the general chemical formula ZnS:Cu.sub.x, M.sub.y, X.sub.z; here, M represents one or more elements from a group comprising the chemical elements Co, In and Ni; X represents one or more elements from a group comprising the halides F, Cl, Br and I; and the following applies: 0<x<0.002 and 0::; y<0.00015 and 0::; z<0.00050. The particles each have cubic phase portions and hexagonal phase portions. When excited by an electrical field, the zinc sulfide luminophore emits a first radiation in the range of the light spectrum between 580 nm and 780 nm. When excited by heating the luminophore to a temperature between 100? C. and 150? C., the zinc sulfide luminophore emits a second radiation in the light spectrum.

A security marking has a physically unclonable function (PUF) wherein the PUF includes a disordered multilayer photonic crystal structure having an electromagnetic transmission and/or reflection spectrum and/or spectra upon receipt of electromagnetic radiation within a photonic bandgap region of the structure that is unique to the structure.