The invention relates to a security feature for safeguarding value documents, comprising particles which are composed of at least two different, spatially separate solid homogeneous phases, wherein each of the phases is detectable and identifiable in a spatially resolved manner by means of a spatially resolving analytical method that is adapted for resolving down to the single-particle level.

The invention relates to a method for the production of a multilayer body, in particular a security element, comprising the following steps:

a) producing a metal layer on a substrate;
b) partial demetalization of the metal layer to form a first item of optical information in a first area of the multilayer body;
c) applying a partial lacquer layer in a second area of the multilayer body to form a second item of optical information, wherein the partial lacquer layer extends at least partially beyond the metal layer;
d) structuring the partial metal layer in the second area using the partial lacquer layer as mask.

The invention further relates to a multilayer body produced in this way.

The invention relates to a method for the production of a multilayer body, in particular a security element, comprising the following steps:

a) producing a metal layer on a substrate;
b) partial demetalization of the metal layer to form a first item of optical information in a first area of the multilayer body;
c) applying a partial lacquer layer in a second area of the multilayer body to form a second item of optical information, wherein the partial lacquer layer extends at least partially beyond the metal layer;
d) structuring the partial metal layer in the second area using the partial lacquer layer as mask.

The invention further relates to a multilayer body produced in this way.

A method for authenticating a security mark containing a photochromic compound can provide higher security performance. The method comprises a process of irradiating a security mark containing a photochromic compound with excitation light, a process of acquiring first security information on a time-dependent change in the absorption spectrum and/or reflection spectrum of the security mark after the irradiation with excitation light, and a process of checking the acquired first security information against previously acquired first security information on the security mark. In this method, the security mark preferably contains two or more photochromic compounds different from one another in color development and/or in quenching rate after the color development in a photochromic reaction.

A method for authenticating a security mark containing a photochromic compound can provide higher security performance. The method comprises a process of irradiating a security mark containing a photochromic compound with excitation light, a process of acquiring first security information on a time-dependent change in the absorption spectrum and/or reflection spectrum of the security mark after the irradiation with excitation light, and a process of checking the acquired first security information against previously acquired first security information on the security mark. In this method, the security mark preferably contains two or more photochromic compounds different from one another in color development and/or in quenching rate after the color development in a photochromic reaction.

A method for preparing three-dimensional perovskite nanopixels of a digital display is provided. The method includes steps of preparing precursor ink by mixing methylammonium halide and lead halide and adding them into another mixture, adding the precursor ink into a nanopipette, placing the nanopipette with the precursor ink above a silicon substrate and apart from the silicon substrate by a certain distance, configuring the nanopipette to come into contact with the Si substrate such that a portion of the precursor ink having an interface surface of a shape of a meniscus is formed between the nanopipette and the silicon substrate, performing rapid evaporation of the portion of the precursor ink to facilitate crystallization of perovskite, moving the nanopipette upwardly at a constant speed such that the crystallization of perovskite proceeds upwardly, and terminating the crystallization of perovskite to generate a freestanding nanopixel for emitting light.

A data carrier in card form includes a card body, which has a first card surface, a second card surface, and a peripheral border. The peripheral border connects the first card surface to the second card surface. The peripheral border also has a first border portion with at least one cutout, with at least one cutout being at least partially filled with a color material, in order in this way to provide a color effect for the first border portion. A method is provided for producing a data carrier in card form.

A data carrier in card form includes a card body, which has a first card surface, a second card surface, and a peripheral border. The peripheral border connects the first card surface to the second card surface. The peripheral border also has a first border portion with at least one cutout, with at least one cutout being at least partially filled with a color material, in order in this way to provide a color effect for the first border portion. A method is provided for producing a data carrier in card form.

A thermal inkjet ink for industrial printing applications includes a primary solvent that includes at least a short chain alcohol, a tackifier that includes a terpene phenolic resin, one or more cosolvents that include at least an ester or a ketone, and a colorant that includes a pigment, a dye, or a combination thereof. The thermal inkjet ink may optionally include other components including, but not limited to, additional tackifiers or resins, one or more surfactants, a lubricant, and a security taggant.

A thermal inkjet ink for industrial printing applications includes a primary solvent that includes at least a short chain alcohol, a tackifier that includes a terpene phenolic resin, one or more cosolvents that include at least an ester or a ketone, and a colorant that includes a pigment, a dye, or a combination thereof. The thermal inkjet ink may optionally include other components including, but not limited to, additional tackifiers or resins, one or more surfactants, a lubricant, and a security taggant.