The present invention relates in particular to a security element (1) for a valuable document, which comprises an array (R) of at least two contiguous or adjacent lines (2, 2′, 2″), at least one of these lines (2) being raised and having two opposing and at least partially inclined sides (20, 21) that each originate along one of the longitudinal and opposing edges (200, 210) of the line (2), characterised by the fact that the two opposing inclined flanks (20, 21) meet at a single, uninterrupted, sinuous junction area (22), that extends in the longitudinal direction of the line (2), the sides (20, 21) having no discontinuities or interruptions at least in the longitudinal direction.

An identification patch having a pattern of plasmonic resonance elements may be used to ensure that an article is counterfeit-proof. The identification patch is formed by laser-induced superplasticity to create a distinctive pattern of resonance elements that each contain a plurality of nanostructures. When the identification patch is irradiated, the pattern of resonance elements produces a unique spectral response that is associated only with the counterfeit-proof article. The counterfeit-proof article may be a metal component or an integrated circuit. The resonant absorption of the plasmonic resonance elements may be measured to verify the authenticity of the article before use of the article.

An identification patch having a pattern of plasmonic resonance elements may be used to ensure that an article is counterfeit-proof. The identification patch is formed by laser-induced superplasticity to create a distinctive pattern of resonance elements that each contain a plurality of nanostructures. When the identification patch is irradiated, the pattern of resonance elements produces a unique spectral response that is associated only with the counterfeit-proof article. The counterfeit-proof article may be a metal component or an integrated circuit. The resonant absorption of the plasmonic resonance elements may be measured to verify the authenticity of the article before use of the article.

Disclosed is an optical film of a double-sided structure, comprising: a body which comprises a polymer, having a first surface and a second surface opposite to each other; an accommodation mechanism provided on the first surface and the second surface; and a filler filled in the accommodation mechanism for forming a graphic structure, wherein the upper surface of the filler is just flush with the first surface and the second surface respectively to form a plane structure; or, the upper surface of the filler is lower than the first surface and the second surface respectively to form a sag structure; the body comprising the accommodation mechanism is an integral structure; the polymer comprises a thermosetting resin, a photocurable resin or a mixture of the thermosetting resin and the photocurable resin. The present application provides the optical film, so as to advantageously reduce a thickness of a film.

Disclosed is an optical film of a double-sided structure, comprising: a body which comprises a polymer, having a first surface and a second surface opposite to each other; an accommodation mechanism provided on the first surface and the second surface; and a filler filled in the accommodation mechanism for forming a graphic structure, wherein the upper surface of the filler is just flush with the first surface and the second surface respectively to form a plane structure; or, the upper surface of the filler is lower than the first surface and the second surface respectively to form a sag structure; the body comprising the accommodation mechanism is an integral structure; the polymer comprises a thermosetting resin, a photocurable resin or a mixture of the thermosetting resin and the photocurable resin. The present application provides the optical film, so as to advantageously reduce a thickness of a film.

An optical device including: a colour shifting layer that exhibits different colours dependent on the angle of incidence of incident light; first and second arrays of at least partially transparent microstructures covering at least part of the layer, configured to modify angle of light to generate a first optically variable effect, wherein: the first array is arranged as a set of image elements that cooperate to exhibit a first image, and the second is arranged to exhibit a second image, wherein the elements of the first array are interlaced with those of the second, and, the microstructures have at least one face that reflects incident light, whereby the first array is configured so, when viewed along a first viewing direction the device exhibits the first image, and the second is configured so, when viewed along a second direction the device exhibits the second image. Also, methods of manufacturing the device.

An optical security element made of a refractive transparent or partially transparent optical material and comprising an optical assembly of a caustic layer having a light-redirecting surface with a relief pattern of given depth and a focal length f.sub.C and an adjacent lens element of focal length f.sub.L configured to redirect incident light received from a point-like light source through it and to form a projected image containing a caustic pattern directly on a retina of an observer. A marked object, as well as a method of visually authenticating an object, and use of optical security elements for authenticating or securing against counterfeiting are also disclosed.

An optical security element made of a refractive transparent or partially transparent optical material and comprising an optical assembly of a caustic layer having a light-redirecting surface with a relief pattern of given depth and a focal length f.sub.C and an adjacent lens element of focal length f.sub.L configured to redirect incident light received from a point-like light source through it and to form a projected image containing a caustic pattern directly on a retina of an observer. A marked object, as well as a method of visually authenticating an object, and use of optical security elements for authenticating or securing against counterfeiting are also disclosed.

A data carrier with a cover layer, a base layer, and an information layer arrangement. The information layer arrangement includes at least a first information layer and a second information layer arranged after the first information layer along an extension direction. The first information layer and the second information layer have different optical properties, and the information layer arrangement has an unmodified region and at least one modified region, the at least one modified region having at least one recess extending at least partially into the first information layer along the extension direction. The at least one modified region is configured to reflect incident electromagnetic waves whereby a first reflection spectrum is generated, the unmodified region is configured to reflect said incident electromagnetic waves whereby a second reflection spectrum is generated, the first reflection spectrum being different from the second reflection spectrum.

A data carrier with a cover layer, a base layer, and an information layer arrangement. The information layer arrangement includes at least a first information layer and a second information layer arranged after the first information layer along an extension direction. The first information layer and the second information layer have different optical properties, and the information layer arrangement has an unmodified region and at least one modified region, the at least one modified region having at least one recess extending at least partially into the first information layer along the extension direction. The at least one modified region is configured to reflect incident electromagnetic waves whereby a first reflection spectrum is generated, the unmodified region is configured to reflect said incident electromagnetic waves whereby a second reflection spectrum is generated, the first reflection spectrum being different from the second reflection spectrum.