A diffractive security device is disclosed including at least a first diffractive structure defined in a carrier layer. The first diffractive structure is an on-axis diffractive zone plate structure of a continuously curved surface configured such that when the device is illuminated by on-axis light a first diffraction pattern generated by the first diffractive structure can be viewed from at least a first side of the device at substantially all viewing angles, the first diffraction pattern exhibiting a reference point or reference line relative to which other features of the first diffraction pattern appear to move when the viewing angle is changed.

A security document, including: a polymer substrate; at least one print layer disposed on one or both sides of the polymer substrate; and a security feature including an image area embodied within the polymer substrate and at least partially covered by the at least one print layer, wherein the security feature is an optical security feature formed in the image area.

This disclosure relates to counterfeit detection and deterrence using advanced signal processing technology including steganographic embedding and digital watermarking. Digital watermark can be used on consumer products, labels, logos, hang tags, stickers and other objects to provide counterfeit detection mechanisms.

The present invention is related to the filed of optically variable security elements comprising a region based on a single cured ink comprising a cholesteric liquid crystal polymer, said region having at least two, preferably at least three, patterns exhibiting, at at least one viewing angle, a different CIE (1976) color index parameter and/or a different position of the selective reflection band for protecting security documents against counterfeiting and/or illegal reproduction. In particular, the present invention relates to processes for manufacturing said features, when the processes comprises the steps of a) applying on a substrate by a rotogravure process with the use of a gravure cylinder having at least two, preferably at least three, different engravings a single cholesteric liquid crystal precursor composition, b) heating the applied composition to bring said composition to a cholesteric liquid crystal state, and c) curing the composition so as to form the region based on a single cured ink comprising a cholesteric liquid crystal polymer.

A security device is provided, comprising: a colour shifting element that exhibits different wavelengths of light at different viewing angles, and; an at least partially transparent light control layer covering at least a part of the colourshifting element and comprising a surface relief adapted to modify the angle of light from the colour shifting element, wherein; a first region of the light control layer comprises a first optical characteristic, whereby light at a first viewing angle from the first region of the light control layer is perceived to have a resultant optical effect that is the resultant of the wavelength of light exhibited at that viewing angle due to the combination of the colour shifting element and the surface relief of the light control layer, and the first optical characteristic, and; a second region of the light control layer either: (i) is substantially colourless such that light at the first viewing angle from the second region is perceived to have a resultant optical effect exhibited at that viewing angle due to the combination of the colour shifting element and the surface relief of the light control layer, or; (ii) comprises a second optical characteristic different from the first optical characteristic, whereby light at the first viewing angle from the second region of the light control layer is perceived to have a resultant optical effect that is the resultant of the wavelength of light exhibited at that viewing angle due to the combination of the colour shifting element and the surface relief of the light control layer, and the second optical characteristic. Methods of manufacture thereof are also disclosed.

Disclosed herein is a method for forming a surface relief microstructure, including the steps of A) applying a curable composition to at least a portion of the frontside of the paper substrate, B) contacting at least a portion of the curable composition with surface relief microstructure, C) curing the composition by using at least one UV lamp which is arranged on the backside of the paper substrate, and D) depositing a metallic layer, and optionally a layer of a transparent high refractive index material, on at least a portion of the cured composition, wherein the UV lamp has an emission peak in a UV-A range of 320 nm to 400 nm and additionally in a near VIS range of 400 nm to 450 nm, the curable composition comprises a photoinitiator which absorbs in the UV-A range and also in the near VIS range.

The present invention relates to a method for creating a hidden pattern on a substrate, wherein a liquid treatment composition comprising at least one acid is deposited by inkjet printing onto a substrate, which comprises at least one external surface comprising a salifiable alkaline or alkaline earth compound.

A security device includes: a substrate having a reflective surface; and a printed array of elements on a substantially flat area of the substrate. Each element is formed of a first material which is at least semi-transparent and a second material, the materials having different optical characteristics. Each element has a raised surface profile relative to the substrate including at least first and second sides sloping from the top of the element to at least respective edges of the element, at which the sides meet a substantially flat base surface of the element parallel to the substrate. The sides have different orientations and each lie at an acute angle to the substrate normal. Under illumination away from the substrate normal, when viewed from first and second viewing angles the element appears to have respectively substantially the optical characteristics of the first and second materials.

A security device is disclosed, including: a substrate having opposing first and second surfaces; on the first surface of the substrate, a surface relief structure formed of one or more cured, at least semi-transparent material(s); and on the second surface of the substrate, a print layer. In at least a first region of the security device in at least part of which the substrate is transparent or translucent, the surface relief structure and the print layer are each defined in accordance with a common image and are in alignment with one another, the surface relief structure exhibiting a first set of feature(s) of the common image and the print layer exhibiting a second set of feature(s) of the common image. The common image is exhibited by the surface relief structure and the print layer in combination with one another and the surface relief structure provides tactility to the common image.

A method of making a multi-layered film includes depositing thin film layers onto a first side of a double-sided transparent substrate. The thin film layers are transparent, and two adjacent layers of said plurality of thin film layers have different refractive indices. One or more absorbers are deposited at an interface formed between two of the thin film layers that are adjacent to one another, or formed by the first side of the substrate and one of the thin film layers. The absorbers absorb selected wavelengths of incident light and reflect part of the incident light after inducing a phase shift. The location of the interface is selected to provide desired wavelengths of absorbed and reflected light. The multi-layered film has a first appearance when viewed from the first side of the substrate and a second appearance when viewed from the second side of the substrate.