The present invention relates to compositions, comprising platelet-shaped transition metal particles, wherein the number mean diameter of the platelet-shaped transition metal particles, present in the composition, is in the range of 15 nm to 1000 nm and the number mean thickness of the platelet-shaped transition metal particles, present in the composition, is in the range of 2 to 40 nm, the transition metal is selected from silver, copper, gold and palladium and the platelet-shaped transition metal particles bear a surface modifying agent of formula A-(CHR.sup.9).sub.r—R.sup.10 (V), wherein if r is 1, A is a C.sub.1-C.sub.25alkyl group substituted with one, or more fluorine atoms; a C.sub.2-C.sub.25alkenyl substituted with one, or more fluorine atoms; a C.sub.2-C.sub.25alkynyl group substituted with one, or more fluorine atoms; a C.sub.3-C.sub.20cycloalkyl group substituted with one, or more fluorine atoms; or a C.sub.6-C.sub.24aryl group substituted with one, or more fluorine atoms, CF.sub.3 or —O—CF.sub.3 groups; if r is 0, A is a C.sub.6-C.sub.24aryl group substituted with one, or more fluorine atoms, CF.sub.3 or —O—CF.sub.3 groups; or a C.sub.7-C.sub.24aralkyl group substituted with one, or more fluorine atoms, CF.sub.3 or —O—CF.sub.3 groups;

R.sup.9 is H, or a C.sub.1-C.sub.4alkyl group; and R.sup.10 is a thiol group, or an amino group.

Surface modification with fluorinated thiols/amines allows to tune the surface properties of silver nanoplatelets in such a way, as to, on the one hand, make them dispersible and colloidally stable in the finished printing ink system, and on the other hand, allow them to migrate to the substrate and print surfaces upon drying of the solvent in the printed layer.

Provided are a highly versatile counterfeit-preventive optical element applicable to both the banknote field and the ID field and an information medium including the optical element. A counterfeit-preventive optical element (1) of an embodiment includes a first layer (2), second layer (3), and a third layer (6) that are stacked in this order. A relief structure (R) is provided between the first layer (2) and the second layer (3), the first layer (2) includes a first region (4) and a second region (5), the first region (4) totally reflects incident light incident from the first layer (2) due to at least one of the angle of a face of the relief structure (R) and the refractive index ratio of the first layer (2) and the second layer (3), and the second region (5) transmits or refracts at least some of incident light incident from the first layer (2) due to one of the angle of a face of the relief structure (R) and the refractive index ratio of the first layer (2) and the second layer (3). The transparency of the second region (5) is higher than the transparency of the first region (4) only when the optical element is observed from the first layer (2) at a particular angle.

The disclosure relates to the technical field of secure identification document, specifically to a method for producing a secure identification document with a color portrait and a secure identification document thereof. The method comprises: etching identity information on the substrate of the data surface of document by laser, and the identity information comprises a black-and-white portrait and text information; printing a color portrait in a blank space of the substrate with color ink to obtain a personalized data surface, and the color portrait is an enlargement of the black-and-white portrait in equal proportion; and printing a transparent protective layer with a transparent varnish on the upper surface of the personalized data surface, wherein the protective layer covers the color portrait.

The present invention is directed to an anti-counterfeiting device comprising a first sensor configured to undergo a first user perceptible change in response to a first biologically produced stimulus that emanates directly from a biological source; and a second sensor configured to undergo a second user perceptible change in response to a second biologically produced stimulus that emanates directly from the biological source. The second biologically produced stimulus is different than the first biologically produced stimulus.

The present invention is directed to an anti-counterfeiting device comprising a first sensor configured to undergo a first user perceptible change in response to a first biologically produced stimulus that emanates directly from a biological source; and a second sensor configured to undergo a second user perceptible change in response to a second biologically produced stimulus that emanates directly from the biological source. The second biologically produced stimulus is different than the first biologically produced stimulus.

A security device and method of making thereof. The security device includes a colour shifting element that exhibits different colours dependent on the angle of incidence of light impinging upon the colour shifting element, and; an at least partially transparent light control layer covering at least a part of the colour shifting element and including a surface relief adapted to modify the angle of light incident upon the light control layer, wherein; the light control layer includes at least first and second functional regions having different refractive indices such that light incident upon the first functional region impinges upon the colour shifting element at a first angle of incidence, and light incident upon the second functional region impinges upon the colour shifting element at a second, different, angle of incidence.

A security device and method of making thereof. The security device includes a colour shifting element that exhibits different colours dependent on the angle of incidence of light impinging upon the colour shifting element, and; an at least partially transparent light control layer covering at least a part of the colour shifting element and including a surface relief adapted to modify the angle of light incident upon the light control layer, wherein; the light control layer includes at least first and second functional regions having different refractive indices such that light incident upon the first functional region impinges upon the colour shifting element at a first angle of incidence, and light incident upon the second functional region impinges upon the colour shifting element at a second, different, angle of incidence.

The present invention relates to a security device comprising a colloidal crystal which exhibits excellent visibility and is also easily manufactured. The security device, according to the present invention, comprises: a substrate; a groove part formed on the substrate; a colloidal crystal positioned in the groove part; and an aging film. The security device, according to the present invention, exhibits excellent security and visibility, and thus may be used for securities, credit cards, security cards, anti-forgery products, etc.

The invention relates to a method for producing a decorative element DE and uses of a decorative element DE produced in this way.

A polarizing layer PS which functions as an analyzer is applied to a transparent optical carrier material TM and a transparent optical functional layer FS is applied to the other side as an image-forming layer BS which consists of an optically anisotropic material OAM.

By spatially structuring the functional layer FS in an image-forming manner, a targeted location-dependent dependency of material properties of the optically anisotropic material OAM is created for producing the image-forming layer BS in the form of an image motif BM.

One or several decorative elements DE produced according to the invention can each be introduced into a light field of a lighting device BV in a desired shape, size and quantity and having settable image motifs BM (image structures) and being disposed at different spatial distances and being freely disposable.

Furthermore, in terms of a device, the decorative element produced according to the invention is intended to be used as an architectural element for creating light-optical effects in the exterior area of buildings, as a design element for interior design or for object design.

The invention relates to a method for producing a decorative element DE and uses of a decorative element DE produced in this way.

A polarizing layer PS which functions as an analyzer is applied to a transparent optical carrier material TM and a transparent optical functional layer FS is applied to the other side as an image-forming layer BS which consists of an optically anisotropic material OAM.

By spatially structuring the functional layer FS in an image-forming manner, a targeted location-dependent dependency of material properties of the optically anisotropic material OAM is created for producing the image-forming layer BS in the form of an image motif BM.

One or several decorative elements DE produced according to the invention can each be introduced into a light field of a lighting device BV in a desired shape, size and quantity and having settable image motifs BM (image structures) and being disposed at different spatial distances and being freely disposable.

Furthermore, in terms of a device, the decorative element produced according to the invention is intended to be used as an architectural element for creating light-optical effects in the exterior area of buildings, as a design element for interior design or for object design.