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.

To provide a hologram, a light-transmissive reflector plate, a screen, and a projection system capable of achieving high transparency and allowing a projected image to be brightly and clearly reflected and observed.

A hologram 1 has a relief part, wherein the hologram 1 reflects a given white light incident thereon at a given angle from one side, while transmits a given white light incident thereon at a given angle from the other side, and diffraction efficiency for transmitted light and diffraction efficiency for reflected light differ from each other.

An identification medium can be used in an opening label, clearly show signs of it having been opened, and also have a superior authenticity-confirming function. The identification medium has a structure including, in the following order as seen from the side of observation: an optical function layer that generates a color shift, a separation layer that is partially formed, a printed layer, and an adhesive layer, in which when an adhesive strength between the adhesive layer and an adherend is set to be Xa, an adhesive strength between the adhesive layer and the printed layer is set to be Xb, and an adhesive strength at a portion in which the separation layer is laminated between the optical function layer and the printed layer is set to be Xc, the adhesive strength of each part is set to satisfy Xa>Xb>Xc or Xb>Xa>Xc.

The present invention relates to complex security elements based on recording materials for optical elements with refractive index modulation, in particular, holograms, which are subsequently coated with specific metallic nano-shaped metal particles, a method for their manufacture, in particular on a paper or on a plastic substrate and a security product obtainable using the security element. A further aspect of the invention is the use of such a security element for the prevention of counterfeit or reproduction of a document of value.

Exemplary systems that may reduce or eliminate the visibility of a boundary between the displaying portions of the system and the non-displaying portions of the system are disclosed. An exemplary system includes a display screen including a plurality of pixels forming a first periodic structure and a frame surrounding at least a portion of the display screen. The frame may include a holographic structure having a second periodic structure. The first pitch of the first periodic structure may be within 0.5 percent to 20 percent of the second pitch of the second periodic structure.

The present invention relates to a security document and/or document of value with a hologram in a visually changeable window as a novel security element, and also to a method for producing the same.

A display device includes an optical sensor configured to image a user eye, an image source configured to provide image light, a holographic film including a plurality of holograms, and a controller. Each hologram is recorded with a same reference beam but recorded differently so as to differently diffract image light received from the light source. The controller is configured to determine, via the optical sensor, a position of the user eye, and adjust, based on the determined position of the user eye, a state of the holographic film such that a particular hologram of the plurality of holograms diffracts image light to the position of the user eye.

In the specification and drawings, a collinear holographic storage medium is described and shown with a recording layer, wherein the lateral linear thermal expansion coefficient of the recording layer is substantially the same as the linear thermal expansion coefficient of the material of the recording layer.

Provided is a photopolymer composition that may exhibit low volume shrinkage during holographic recording and may prevent a photosensitive dye from remaining unbleached after holographic recording.

Systems, articles, and methods that integrate photopolymer film with eyeglass lenses are described. One or more hologram(s) may be recorded into/onto the photopolymer film to enable the lens to be used as a transparent holographic combiner in a wearable heads-up display employing an image source, such as a microdisplay or a scanning laser projector. The methods of integrating photopolymer film with eyeglass lenses include: positioning photopolymer film in a lens mold and casting the lens around the photopolymer film; sandwiching photopolymer film in between two portions of a lens; applying photopolymer film to a concave surface of a lens; and/or affixing a planar carrier (with photopolymer film thereon) to two points across a length of a concave surface of a lens. Respective lenses manufactured/adapted by each of these processes are also described.