Abstract:
A display panel assembly comprises a transflective holographic screen, i.e., a transparent screen that reflects light from a projection system, comprising at least a volume hologram, a first protective element and a second protective element, each arranged in contact with the volume hologram such that the volume hologram is sandwiched between the first protective element and the second protective element. The display panel assembly further comprises a projection system focusing an image on the volume hologram comprising at least projection optics, mounting means arranged to fixedly mount the projection system relatively to the transflective holographic screen. The volume hologram comprises a plurality of diffractive patterns disposed in sequence across the volume hologram, each of the plurality of diffractive patterns being configured to diffuse the light rays from the projection system in a determined direction corresponding to the specific diffractive pattern and oriented towards a position of an intended eye of a user wearing the display panel assembly.
Abstract:
The invention relates to a method for producing a security element having a holographic layer in which a hologram is arranged, characterized by at least the following steps: a) providing the holographic layer; b) exposing the holographic layer at least in sections via a master hologram to produce a hologram copy in the holographic layer; c) printing the holographic layer at least in sections with an ink, forming a printed feature, wherein the ink comprises the melt of a dye or a colorless component or a solvent and a dye dissolved therein or a colorless component dissolved therein; d) fixing the exposed holographic layer to produce the hologram in the holographic layer, wherein the printed feature and the hologram are arranged in the holographic layer such that the printed feature and the hologram overlap at least in sections. The invention further relates to a security feature which is produced or can be produced by said method.
Abstract:
The subject matter described herein includes a curved VPH grating with tilted fringes and spectrographs, both retroreflective and transmissive, that use such gratings. A VPH grating according to the subject matter described herein includes a first curved surface for receiving light to be diffracted. The grating includes an interior region having tilted fringes to diffract light that passes through the first surface. The grating further includes a second curved surface bounding the interior region on a side opposite the first surface and for passing light diffracted by the fringes.
Abstract:
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.
Abstract:
A method of making a hologram (10) includes recording a first hologram in a holographic recording medium (14) at a first deformation ratio; changing the first deformation ratio to a second deformation ratio that is different from the first deformation ratio; and recording a second hologram in the holographic recording medium (14) at the second deformation ratio to form a recorded holographic medium.
Abstract:
We propose a method of detecting the presence of certain chemical and biochemical substances by virtue of the fact that they are, or have attached to them, either a dye molecule which acts as a photosensitizer for a holographic recording or erasing process, or another essential molecular component of the holographic recording material such as a monomer or a free radical generator. The recording or erasing process utilizes a photopolymer system consisting of a monomer and a crosslinking monomer, a free radical generator, a photosensitizer and, additionally, a polymeric binder when dry formulations are required. Applications are broad ranging. Examples in diagnostics, printing, security, and environmental monitoring are given.
Abstract:
The present invention relates to a method and apparatus for producing a hologram, in particular a dot matrix volume hologram. A holographic recording system (1) comprises a source of optical radiation (7), a transparent or partially transparent holographic recording medium 6 and an optical system (10). The recording medium (6) has a first side (25), a second side (26) and a recording volume (36), the second side (26) being opposite to said first side (25) and the recording volume (36) being between said sides (25, 26). The recording medium (6) is positioned between the source of optical radiation (7) and the optical system (10) so that the first side (25) is presented towards the source of optical radiation (7) and the second side (26) is presented towards the optical system. The source (7) is arranged to project incident optical radiation (20) onto the first side (25) and through the recording volume (36) towards the optical system (10). The optical system (10) is arranged to redirect (32) the optical radiation back onto said second side (26) and into the recording volume (36) so that said incident (20) and redirected (32) optical radiation intersect within the recording volume (36) at an obtuse angle (34) to create an interference pattern (38) from which a holographic recording may be made.
Abstract:
A holographic storage media for storing digital data in the form of an interference grating is provided which includes a plurality of slabs of photorefractive material (72) arranged in a stack, with one edge thereof comprising an incident face (74). A data beam (39) having data superimposed thereon and a reference beam (38) are input to the face (74) to record a holographic image of the data in one of the slabs (72). Each of the slabs has a plurality of adjacent storage regions formed therein. The data and reference beams are disposed in a plane perpendicular to both the face (74) and the side (75) of the slabs (72), such that the reference beam (38) is confined within the slab (72) for all angles of the reference beam (38).
Abstract:
Methods and systems for presensitizing film, including causing a presensitization effect on a region of a film, the presensitization effect, as a function of time, exhibiting a presensitization effect peak after a peak time from an initiation of the presensitization effect, and exposing, after a delay time, substantially the same region of the film to a spectrum of information-containing electromagnetic radiation, the presensitization effect at the delay time being substantially equal to the presensitization effect peak.