A method of forming a security device includes: a holographic image layer, diffusion element, and barrier layer. A region of the barrier layer includes a heat-transformable material. The method further includes selectively applying heat at a plurality of positions within the region of the barrier layer, in accordance with a predetermined pattern, so as to modify the heat-transformable material such that the region of the barrier layer is selectively rendered passable to the diffusible substance at each of the plurality of positions, thereby permitting diffusion of the diffusible substance between the regions of the diffusion element and the holographic image layer such that, at a plurality of positions within the region of the holographic image layer and corresponding to the predetermined pattern, the volume hologram is dimensionally modified so as to become viewable in a second observable colour, different from the first observable colour.

In a first aspect, a multilayer film includes a holographic image layer, a first heat-shrinkable layer and a first adhesive layer between the holographic image layer and the first heat-shrinkable layer. In a second aspect, an authentication label includes a holographic image layer, a first heat-shrinkable layer, a first adhesive layer between the holographic image layer and the first heat-shrinkable layer, and a back adhesive layer.

A main object of the present invention is to provide a method of producing a volume hologram laminate which can regenerate a hologram image in an arbitrary wavelength by a simple process. To attain the object, the present invention provides a method of producing a volume hologram laminate using a volume hologram forming substrate which comprises: a substrate, a volume hologram layer formed on the substrate and containing a photopolymerizable material, a resin layer, formed on the substrate so as to contact to the volume hologram layer, containing a resin and a polymerizable compound, characterized in that the producing method comprises processes of: a hologram recording process to record a volume hologram to the volume hologram layer, a substance transit process of transiting the polymerizable compound to the volume hologram layer, and an after-treatment process of polymerizing the polymerizable compound.

Systems, devices, and methods for controlled hologram playback shifting are described. The playback of a hologram may be shifted to a longer wavelength by diffusing donor material into the hologram in a controlled manner. A hologram may include a set of fringes, holographic recording medium and donor material. An apparatus to controllable shift playback angle of a hologram can include a hologram film holder, donor film holder, one or more light sources, light sensor, and curing lamp. A method may include monitoring playback light until an amount of playback shift occurs, and in response fixing a piece of hologram film and physically de-coupling a donor film therefrom.

When coating a document surface (3) having relief-like information (1) carrying personal data, for example, with a monomer-containing liquid UV adhesive (4) across the entire surface and then laminating thereon a volume hologram (2), the varying adhesive thicknesses between the volume hologram and the document surface resulting from the relief cause differentiated swelling and thereby a differentiated color shift of the hologram. After the desired color shift is achieved, the UV adhesive (4) is completely cured. In this way, individual holographic information is obtained, which is located exactly above the relief-like information of the document. With this method, holographic overlays comprising personal data and a passport picture can be produced, and it is possible to link defined optical document information to the hologram in an accurately positioned manner, so that information is visible both non-diffractively and, from a different viewing angle, holographically in a different color.

The invention pertains in a first aspect to a multilayer film that includes a frangible holographic image layer and an adhesive layer adjacent to a side of the holographic image layer; and, an additional temporary support layer that is adjacent a side of the holographic image layer that is opposite the adhesive layer, and provides integrity to the multilayer film. The additional temporary support layer can be a polyester film that is removable from the multilayer film at 10 gram per inch peel strength; or, can be a heat-shrinkable film that is removable from the multilayer film with the application of heat. After application of the multilayer film to a substrate, the holographic image layer forms an exterior surface of the multilayer film. In a second aspect, the invention pertains to an authentication label of the multilayer film for attachment to a substrate, wherein a side of the adhesive layer that is opposite the holographic image layer contacts the substrate, and the holographic image layer forms an exterior surface of the label.

We describe a window assembly comprising: a window pane comprising a glass or plastic sheet; and a layer of holographic recording medium attached to said glass or plastic sheet; wherein said layer of holographic recording medium has recorded within the medium a volume hologram configured to direct light incident onto said glass or plastic sheet to propagate within a thickness of said glass or plastic sheet. In embodiments the volume hologram is fabricated by recording a transmission hologram and shrinking the recorded hologram to convert the transmission hologram to an edge-directing hologram configured to direct light in a direction to be totally internally reflected within the window pane, for example at greater than 40, 50, 60, 70, 75 or 80 to a normal to the surface of the hologram.

A main object of the present invention is to provide a method of producing a volume hologram laminate which can regenerate a hologram image in an arbitrary wavelength by a simple process. To attain the object, the present invention provides a method of producing a volume hologram laminate using a volume hologram forming substrate which comprises: a substrate, a volume hologram layer formed on the substrate and containing a photopolymerizable material, a resin layer, formed on the substrate so as to contact to the volume hologram layer, containing a resin and a polymerizable compound, characterized in that the producing method comprises processes of: a hologram recording process to record a volume hologram to the volume hologram layer, a substance transit process of transiting the polymerizable compound to the volume hologram layer, and an after-treatment process of polymerizing the polymerizable compound.