Abstract: A method for securing a document (1), and a secure document (1) including a data medium (2) and an optical security component (3). The medium (2) includes a first surface (12) and a second surface (13). The optical component (3) includes an element (21) for generating optical effects and an adhesive element (5) adhering to the first surface (21) of the medium (2). Customization data (16,17,18,19,20) are written on the secure document (1). The secure document (1) also includes an additional sealing component (4) including adhesive element (10) adhering to the second surface (13) of the medium (2), the medium (2) including at least one perforation (14, 15) arranged so that the optical (3) and additional (4) components are bonded to each other through the perforation (14, 15).

Abstract: A method of preparing an optical security component having a metallic appearance and having a diffraction grating. The method includes the following steps: preparing a transparent polyester film; depositing a stamping layer, into which the hologram producer has pressed the appropriate microstructures; stamping; vacuum depositing a fine layer of a dielectric material having a high optical index; coating or printing at least one layer of translucent coloured varnish; and vacuum depositing a layer of aluminium. An optical security component thus produced is also disclosed.

Abstract: Methods and adhesive labels useful in marking products or documents by applying these to substrates. A mark such as a barcode, photograph or characters are formed directly on the substrate and the adhesive label is applied over it. The adhesive label includes a concealing film layer which is transparent to a first wavelength outside the visible region, a diffractive optical mark with a transparent reflective layer and an adhesive layer. The first wavelength may be infrared allowing the underlying mark to be read by an IR laser. The adhesive labels are formed as to allow them to be continuously separated from a temporary detachment layer, thereby exposing the adhesive layer, and affixed to the document.

Abstract: A method for marking articles or documents by placing on a substrate (1) a multi-layer optical complex consisting of an identifying portion (2, 7) such as bar codes, a photograph or characters, and an authenticating portion consisting of a diffracting optical mark, said portions being arranged one on top of the other in such a way that they cannot be separated without destroying the authenticating portion. A protected document is also disclosed which comprises an indivisible stack consisting of a printed portion (2, 7) forming an identifier read by reflection in a first wavelength band, and coated with a lacquer (5) that is opaque in the visible spectrum and has a transmission window including said first wavelength band, as well as a transparent reflective layer (4) forming a diffracting optical mark. A marking system for carrying out the method, and a device for checking said article or document, are also disclosed.